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Sample records for hypotension marked diuresis

  1. Nociceptin/orphanin FQ (N/OFQ)-evoked bradycardia, hypotension, and diuresis are absent in N/OFQ peptide (NOP) receptor knockout mice.

    PubMed

    Burmeister, Melissa A; Ansonoff, Michael A; Pintar, John E; Kapusta, Daniel R

    2008-09-01

    Intracerebroventricular administration of the opioid-like peptide nociceptin/orphanin FQ (N/OFQ) produces bradycardia, hypotension, and diuresis in mice. We hypothesized that these responses are solely caused by selective activation of central N/OFQ peptide (NOP) receptors. To test this premise, we first examined whether i.c.v. N/OFQ produced dose-dependent diuretic and cardiovascular depressor responses in commercially available C57BL/6 mice. Next, using doses established in these studies, we examined the renal excretory and cardiovascular responses to i.c.v. N/OFQ in conscious transgenic NOP receptor knockout mice (NOP(-/-)). In metabolic studies, i.c.v. N/OFQ, but not saline vehicle, dose-dependently increased urine output (V) in NOP(+/+); this response was significant at 3 nmol (N/OFQ, V = 0.39 +/- 0.10 ml/2 h; saline, 0.08 +/- 0.05 ml/2 h). The N/OFQ-evoked diuresis was absent in littermate NOP(-/-) (N/OFQ, V = 0.06 +/- 0.06 ml/2 h; saline, 0.03 +/- 0.03 ml/2 h). There were no significant changes in urinary sodium or potassium excretion or free water clearance in either group. In telemetry studies, i.c.v. N/OFQ dose dependently lowered heart rate (HR) and mean arterial pressure (MAP). At 3 nmol N/OFQ, both HR and MAP were reduced in NOP(+/+) (peak DeltaHR = -217 +/- 31 bpm; peak DeltaMAP =-47 +/- 7 mm Hg) compared with saline (peak DeltaHR =-14 +/- 5 bpm; peak DeltaMAP = 2 +/- 3 mm Hg). These N/OFQ-evoked bradycardic and hypotensive responses were absent in NOP(-/-) (peak DeltaHR =-13 +/- 17 bpm; peak DeltaMAP =-2 +/- 4 mm Hg, respectively). Basal 24-h cardiovascular and renal excretory function were not different between NOP(-/-) and NOP(+/+) mice. These results establish that the bradycardia, hypotension and diuresis produced by centrally administered N/OFQ are mediated by selective activation of NOP receptors.

  2. Osmotic diuresis

    MedlinePlus

    ... page: //medlineplus.gov/ency/article/001266.htm Osmotic diuresis To use the sharing features on this page, please enable JavaScript. Osmotic diuresis is increased urination due to the presence of ...

  3. Spontaneous intracranial hypotension manifesting as a unilateral subdural hematoma with a marked midline shift.

    PubMed

    Inamasu, Joji; Moriya, Shigeta; Shibata, Junpei; Kumai, Tadashi; Hirose, Yuichi

    2015-01-01

    Spontaneous intracranial hypotension (SIH) is a syndrome in which hypovolemia of the cerebrospinal fluid (CSF) results in various symptoms. Although its prognosis is usually benign, cases with a rapid neurologic deterioration resulting in an altered mental status have been reported. One of the characteristic radiographic findings in such cases is the presence of bilateral accumulation of subdural fluid (hematoma/hygroma). When SIH-related subdural hematoma is present only unilaterally with a concomitant midline shift, making an accurate diagnosis may be challenging, and inadvertent hematoma evacuation may result in further neurologic deterioration. We report a 58-year-old woman with an altered mental status who had visited a local hospital and in whom a brain CT showed a unilateral subdural hematoma with a marked midline shift. She was referred to our department because of her neurologic deterioration after hematoma evacuation. A CT myelography revealed a massive CSF leakage in the entire thoracic epidural space. She made a full neurologic recovery following blood patch therapy. Our case is unique and educational because the suspicion for SIH as an underlying cause of subdural hematoma is warranted in nongeriatric patients not only with bilateral but also unilateral lesions. An immediate search for CSF leakage may be important in cases with failed hematoma evacuation surgery.

  4. Orthostatic Hypotension (Postural Hypotension)

    MedlinePlus

    ... while you're standing and will compare the measurements. Your doctor will diagnose orthostatic hypotension if you ... breathing: You breathe in deeply and push the air out through your lips, as if you were ...

  5. Orthostatic Hypotension

    MedlinePlus

    ... lightheadedness, blurred vision, and syncope (temporary loss of consciousness). × Definition Orthostatic hypotension is a sudden fall in ... lightheadedness, blurred vision, and syncope (temporary loss of consciousness). View Full Definition Treatment When orthostatic hypotension is ...

  6. A case of marked diuresis by combined dopamine and atrial natriuretic peptide administration without renal injury in acute decompensated heart failure.

    PubMed

    Kamiya, Masataka; Sato, Naoki; Akiya, Mai; Okazaki, Hirotake; Takahashi, Yasuhiro; Mizuno, Kyoichi

    2013-01-01

    Renal injury is an important factor for worsening outcome in acute decompensated heart failure (ADHF). An 81-year-old woman was admitted due to ADHF with dyspnea and mild peripheral edema. The patient was managed with intravenous administration of atrial natriuretic peptide (ANP) at a dose of 0.0125 μg/kg/minute, which did not control volume overload even at an increased dose of 0.025 μg/kg/minute. After a low dose of dopamine (DA) of 1.0 μg/kg/ minute was added, urine output increased markedly to 120 from 30 mL/hour. Furthermore, her heart rate decreased to 80-100 from 120 bpm and the congestion improved with a reduced brain natriuretic peptide level. Interestingly, the combination of ANP and DA therapy reduced serum creatinine as well as the levels of urinary liver-type fatty acid binding protein, a novel reno-tubular stress marker, by 98.9%, and an oxidative stress marker, urinary 8-hydroxydeoxyguanosine, by 88.2% from baseline levels. Thus, this ADHF patient, a nonresponder to ANP alone, improved without renal injury when administered combination therapy consisting of low doses of ANP and DA, suggesting that this combined therapy might be useful for better management of ADHF in patients without diuretic responses with ANP alone. Further prospective studies are warranted.

  7. Orthostatic hypotension

    NASA Technical Reports Server (NTRS)

    Grimm, J. J.

    1980-01-01

    Following a brief physiopathological review, orthostatic hypotension is classified into three groups: organic, functional and medication-dependent. The importance of etiological diagnosis, the use of objective tests and appropriate therapy, especially concerning the organic forms, is stressed.

  8. Mark.

    ERIC Educational Resources Information Center

    Lipman, Matthew; Smith, Theresa L., Ed.

    Mark is the central character in this story designed to help adolescents formulate a philosophy of values. The story is well suited for use in high school social studies courses and/or in philosophy or guidance units. Mark's thoughts and actions are reported as he interacts with his family, friends, acquaintances, and individuals of authority…

  9. Orthostatic hypotension

    NASA Technical Reports Server (NTRS)

    Ninet, J.

    1981-01-01

    Basic orientation of the article, by the leader of a group of medical researchers associated with hospitals in Lyon, France, is toward definition and classification. A table divides OH (orthostatic hypotension) according to physiopathological classification into sympathicotonic and asympathicotonic types and then each of these into primary and secondary with subdivisions. The figure sketches organization and functioning of the baroreflex arc. Applications to clinical study of circulatory reflexes, listing measurement tests and the biological study of hormonal regulation listing the appropriate kinds of studies. Data are not given.

  10. Surfactant therapy and spontaneous diuresis.

    PubMed

    Bhat, R; John, E; Diaz-Blanco, J; Ortega, R; Fornell, L; Vidyasagar, D

    1989-03-01

    The effect of artificial surfactant therapy on renal function and the onset of spontaneous diuresis was prospectively evaluated in 19 infants with hyaline membrane disease in a double-blind, controlled study. Twelve infants were in the surfactant group; seven infants received placebo (0.9% saline solution). There was no difference in the time of onset of spontaneous diuresis (as defined by output greater than or equal to 80% of intake). The glomerular filtration rate, determined by endogenous creatinine clearance, was also similar in the surfactant- and placebo-treated infants during the first 3 days of life. The fractional excretion of sodium was significantly higher in the placebo group at 24 hours and 36 hours. Infants in the placebo group had a higher negative sodium balance than those in the surfactant group. Ventilatory status improved significantly soon after surfactant treatment, as evidenced by improvement in the alveolar/arterial oxygen pressure ratio and by a lower mean airway pressure. These data suggest that ventilatory status can be improved without diuresis; the factors that regulate diuresis are multiple and not fully understood.

  11. [Hypotension from endocrine origin].

    PubMed

    Vantyghem, Marie-Christine; Douillard, Claire; Balavoine, Anne-Sophie

    2012-11-01

    Hypotension is defined by a low blood pressure either permanently or only in upright posture (orthostatic hypotension). In contrast to hypertension, there is no threshold defining hypotension. The occurrence of symptoms for systolic and diastolic measurements respectively below 90 and 60 mm Hg establishes the diagnosis. Every acute hypotensive event should suggest shock, adrenal failure or an iatrogenic cause. Chronic hypotension from endocrine origin may be linked to adrenal failure from adrenal or central origin, isolated hypoaldosteronism, pseudohypoaldosteronism, pheochromocytoma, neuro-endocrine tumors (carcinoïd syndrome) or diabetic dysautonomia. Hypotension related to hypoaldosteronism associates low blood sodium and above all high blood potassium levels. They are generally classified according to their primary (hyperreninism) or secondary (hyporeninism) adrenal origin. Isolated primary hypoaldosteronisms are rare in adults (intensive care unit, selective injury of the glomerulosa area) and in children (aldosterone synthase deficiency). Isolated secondary hypoaldosteronism is related to mellitus diabetes complicated with dysautonomia, kidney failure, age, iatrogenic factors, and HIV infections. In both cases, they can be associated to glucocorticoid insufficiency from primary adrenal origin (adrenal failure of various origins with hyperreninism, among which congenital 21 hydroxylase deficiency with salt loss) or from central origin (hypopituitarism with hypo-reninism). Pseudohypoaldosteronisms are linked to congenital (type 1 pseudohypoaldosteronism) or acquired states of resistance to aldosterone. Acquired salt losses from enteric (total colectomy with ileostomy) or renal (interstitial nephropathy, Bartter and Gitelman syndromes…) origin might be responsible for hypotension and are associated with hyperreninism-hyperaldosteronism. Hypotension is a rare manifestation of pheochromocytomas, especially during surgical removal when the patient has not been

  12. Sporadic hypokalemic paralysis caused by osmotic diuresis in diabetes mellitus.

    PubMed

    Vishnu, Venugopalan Y; Kattadimmal, Anoop; Rao, Suparna A; Kadhiravan, Tamilarasu

    2014-07-01

    A wide variety of neurological manifestations are known in patients with diabetes mellitus. We describe a 40-year-old man who presented with hypokalemic paralysis. On evaluation, we found that the cause of the hypokalemia was osmotic diuresis induced by marked hyperglycemia due to undiagnosed diabetes mellitus. The patient had an uneventful recovery with potassium replacement, followed by glycemic control with insulin. Barring a few instances of symptomatic hypokalemia in the setting of diabetic emergencies, to our knowledge uncomplicated hyperglycemia has not been reported to result in hypokalemic paralysis.

  13. What Causes Hypotension?

    MedlinePlus

    ... Related Topics Anemia Arrhythmia Cardiogenic Shock Heart Attack Heart Valve Disease Send a link to NHLBI to someone by ... hypotension, including: Heart conditions, such as heart attack , heart valve disease , bradycardia (a very low heart rate), and heart ...

  14. Living with Hypotension

    MedlinePlus

    ... Clinical Trials Links Related Topics Anemia Arrhythmia Cardiogenic Shock Heart Attack Heart Valve Disease Send a link ... about your blood pressure. Severe hypotension linked to shock is an emergency. Shock can lead to death ...

  15. Types of Hypotension

    MedlinePlus

    ... adults more often than people in other age groups. Children often outgrow NMH. Severe Hypotension Linked to Shock Shock is a life-threatening condition in which blood pressure drops so low that the brain, kidneys, and ...

  16. Effects of vasopressin administration on diuresis of water immersion in normal humans

    NASA Technical Reports Server (NTRS)

    Epstein, M.; Denunzio, A. G.; Loutzenhiser, R. D.

    1981-01-01

    The influence of vasopressin suppression on the diuresis encountered during water immersion is investigated in studies on normal humans immersed to the neck. Six hydrated male subjects were studied on two occasions while undergoing 6 h of immersion without or during the administration of aqueous vasopressin for the initial 4 h. Neck immersion is found to result in a significant increase in urinary flow rate beginning in the first hour and persisting throughout the immersion. The administration of vasopressin markedly attenuated the diuretic response throughout the period of infusion, while cessation of vasopressin administration during the final 2 h of immersion resulted in a marked offset of the antidiuresis. Results thus support the view that the suppression of antidiuretic hormone contributes to the immersion diuresis of hydrated subjects.

  17. Immersion diuresis without expected suppression of vasopressin

    NASA Technical Reports Server (NTRS)

    Keil, L. C.; Silver, J. E.; Wong, N.; Spaul, W. A.; Greenleaf, J. E.; Kravik, S. E.

    1984-01-01

    There is a shift of blood from the lower parts of the body to the thoracic circulation during bed rest, water immersion, and presumably during weightlessness. On earth, this central fluid shift is associated with a profound diuresis. However, the mechanism involved is not yet well understood. The present investigation is concerned with measurements regarding the plasma vasopressin, fluid, electrolyte, and plasma renin activity (PRA) responses in subjects with normal preimmersion plasma vasopressin (PVP) concentration. In the conducted experiments, PRA was suppressed significantly at 30 min of immersion and had declined by 74 percent by the end of the experiment. On the basis of previously obtained results, it appears that sodium excretion during immersion may be independent of aldosterone action. Experimental results indicate that PVP is not suppressed by water immersion in normally hydrated subjects and that other factors may be responsible for the diuresis.

  18. Causes of chronic orthostatic hypotension

    NASA Technical Reports Server (NTRS)

    Robertson, D.; Robertson, R. M.

    1994-01-01

    OBJECTIVE: To determine the frequency of various causes of orthostatic hypotension. DESIGN: Survey. SETTING: Tertiary referral center. PATIENTS: One hundred patients with moderate to severe orthostatic hypotension. RESULTS: Twenty-seven percent of the patients had primary autonomic failure, 35% had secondary autonomic failure, and 38% had hypotension without evidence of generalized autonomic degeneration. CONCLUSIONS: In a tertiary referral center, only a minority of patients with severe orthostatic hypotension will have Shy-Drager syndrome or Bradbury-Eggleston syndrome as their primary disease. Occasional patients who initially appear to have Bradbury-Eggleston syndrome ultimately prove to have Shy-Drager syndrome or paraneoplastic autonomic failure. Antidepressant drugs, even in low doses, remain a major overlooked cause of orthostatic hypotension.

  19. Norepinephrine-induced diuresis in chronically ethanol-treated rats

    SciTech Connect

    Pohorecky, L.A. )

    1989-01-01

    Previous research from this laboratory indicated that noradrenergic mechanisms might mediate ethanol diuresis. Experiments described here examined changes in sensitivity of noradrenergic mechanisms in animals chronically treated with ethanol. Norepinephrine hydrochloride (0-12 ug intracerebroventricularly) produced dose-dependent diuresis in control and ethanol treated rats on the first day of treatment. Tolerance to ethanol diuresis was present after 10 day of ethanol treatment. Lack of responsiveness to norepinephrine-induced diuresis was evident only on the 20th day of treatment in both the ethanol and dextrin-maltose groups of rats. These results indicate a temporal dissociation between the tolerance to ethanol-induced and norepinephrine-induced diuresis and suggest that norepinephrine may not play a primary role in the development of tolerance to the diuretic action of ethanol.

  20. Treatment of Post-SCI Hypotension

    ClinicalTrials.gov

    2017-01-13

    Spinal Cord Injury; Autonomic Dysreflexia; Orthostatic Hypotension; Baroreceptor Integrity; Sympathetic Integrity; Vagal Integrity; Hypotension; Cerebral Blood Flow; Blood Pressure; Venous Occlusion Plethysmography

  1. Hypotension in Severe Dimethoate Self-Poisoning

    PubMed Central

    Davies, James; Roberts, Darren; Eyer, Peter; Buckley, Nick; Eddleston, Michael

    2008-01-01

    Introduction Acute self-poisoning with the organophosphorus (OP) pesticide dimethoate has a human case fatality three-fold higher than poisoning with chlorpyrifos despite similar animal toxicity. The typical clinical presentation of severe dimethoate poisoning is quite distinct from that of chlorpyrifos and other OP pesticides: many patients present with hypotension that progresses to shock and death within 12–48 h post-ingestion. The pathophysiology of this syndrome is not clear. Case reports We present here three patients with proven severe dimethoate poisoning. Clinically, all had inappropriate peripheral vasodilatation and profound hypotension on presentation, which progressed despite treatment with atropine, i.v. fluids, pralidoxime chloride, and inotropes. All died 2.5–32 h post-admission. Continuous cardiac monitoring and quantification of troponin T provided little evidence for a primary cardiotoxic effect of dimethoate. Conclusion Severe dimethoate self-poisoning causes a syndrome characterized by marked hypotension with progression to distributive shock and death despite standard treatments. A lack of cardiotoxicity until just before death suggests that the mechanism is of OP-induced low systemic vascular resistance (SVR). Further invasive studies of cardiac function and SVR, and post-mortem histology, are required to better describe this syndrome and to establish the role of vasopressors and high-dose atropine in therapy. PMID:19003596

  2. Excess diuresis and natriuresis during acute sleep deprivation in healthy adults.

    PubMed

    Kamperis, Konstantinos; Hagstroem, Soren; Radvanska, Eva; Rittig, Soren; Djurhuus, Jens Christian

    2010-08-01

    The transition from wakefulness to sleep is associated with a pronounced decline in diuresis, a necessary physiological process that allows uninterrupted sleep. The aim of this study was to assess the effect of acute sleep deprivation (SD) on urine output and renal water, sodium, and solute handling in healthy young volunteers. Twenty young adults (10 male) were recruited for two 24-h studies under standardized dietary conditions. During one of the two admissions, subjects were deprived of sleep. Urine output, electrolyte excretions, and osmolar excretions were calculated. Activated renin, angiotensin II, aldosterone, arginine vasopressin, and atrial natriuretic peptide were measured in plasma, whereas prostaglandin E(2) and melatonin were measured in urine. SD markedly increased the diuresis and led to excess renal sodium excretion. The effect was more pronounced in men who shared significantly higher diuresis levels during SD compared with women. Renal water handling and arginine vasopressin levels remained unaltered during SD, but the circadian rhythm of the hormones of the renin-angiotensin-aldosterone system was significantly affected. Urinary melatonin and prostaglandin E(2) excretion levels were comparable between SD and baseline night. Hemodynamic changes were characterized by the attenuation of nocturnal blood pressure dipping and an increase in creatinine clearance. Acute deprivation of sleep induces natriuresis and osmotic diuresis, leading to excess nocturnal urine production, especially in men. Hemodynamic changes during SD may, through renal and hormonal processes, be responsible for these observations. Sleep architecture disturbances should be considered in clinical settings with nocturnal polyuria such as enuresis in children and nocturia in adults.

  3. Hypotensive Resuscitation among Trauma Patients

    PubMed Central

    Carrick, Matthew M.; Leonard, Jan; Slone, Denetta S.; Mains, Charles W.

    2016-01-01

    Hemorrhagic shock is a principal cause of death among trauma patients within the first 24 hours after injury. Optimal fluid resuscitation strategies have been examined for nearly a century, more recently with several randomized controlled trials. Hypotensive resuscitation, also called permissive hypotension, is a resuscitation strategy that uses limited fluids and blood products during the early stages of treatment for hemorrhagic shock. A lower-than-normal blood pressure is maintained until operative control of the bleeding can occur. The randomized controlled trials examining restricted fluid resuscitation have demonstrated that aggressive fluid resuscitation in the prehospital and hospital setting leads to more complications than hypotensive resuscitation, with disparate findings on the survival benefit. Since the populations studied in each randomized controlled trial are slightly different, as is the timing of intervention and targeted vitals, there is still a need for a large, multicenter trial that can examine the benefit of hypotensive resuscitation in both blunt and penetrating trauma patients. PMID:27595109

  4. [Orthostatic hypotension; that great unknown].

    PubMed

    Velilla-Zancada, S M; Prieto-Díaz, M A; Escobar-Cervantes, C; Manzano-Espinosa, L

    2016-11-16

    Orthostatic hypotension is an anomaly of growing interest in scientific research. Although certain neurogenic diseases are associated with this phenomenon, it can also be associated with non-neurological causes. Although orthostatic hypotension is defined by consensus as a decrease in the systolic blood pressure of at least 20mmHg, or a decrease in diastolic blood pressure of at least 10mmHg, within 3min of standing, the studies differ on how to diagnose it. Orthostatic hypotension is associated with certain cardiovascular risk factors and with drug treatment, but the results are contradictory. The purpose of this review is to update the knowledge about orthostatic hypotension and its treatment, as well as to propose a method to standardise its diagnosis.

  5. Primary neurogenic orthostatic hypotension

    PubMed Central

    Hughes, R. C.; Cartlidge, N. E. F.; Millac, P.

    1970-01-01

    Eight further cases of neurogenic orthostatic hypotension are described together with a necropsy study on one case. Three cases showed evidence of autonomic dysfunction in isolation, while in five cases this was accompanied by evidence of more diffuse central nervous system degeneration. (Parkinsonism, cerebellar ataxia, dementia, pyramidal signs, bulbar weakness, and muscular wasting were all seen in varying proportions.) The various clinical presentations, investigations, pathology, treatment, and prognosis are discussed. In the experience of the authors, when assessed, an abnormal Valsalva response is invariable, confirming the breakdown of the circulatory reflex. A normal vasopressor response is likewise invariable, eliminating an abnormality of blood vessels themselves, and confirming the lesion as neurogenic. The demonstration of loss of sweating to indirect body heating, which also is usual suggests that the defect is central or on the efferent side of the reflex and a normal pilo-erector response to acetylcholine confirms this as preganglionic. Emphasis is laid on the non-specificity of many accepted physiological tests in this disorder and on the delay in diagnosis consequent upon the variable presentation. PMID:5431725

  6. Sleep deprivation induces excess diuresis and natriuresis in healthy children.

    PubMed

    Mahler, B; Kamperis, K; Schroeder, M; Frøkiær, J; Djurhuus, J C; Rittig, S

    2012-01-15

    Urine production is reduced at night, allowing undisturbed sleep. This study was undertaken to show the effect of sleep deprivation (SD) on urine production in healthy children. Special focus was on gender and children at an age where enuresis is still prominent. Twenty healthy children (10 girls) underwent two 24-h studies, randomly assigned to either sleep or SD on the first study night. Diet and fluid intake were standardized. Blood samples were drawn every 4 h during daytime and every 2 h at night. Urine was fractionally collected. Blood pressure and heart rate were noninvasively monitored. Blood was analyzed for plasma antidiuretic hormone (AVP), atrial natriuretic peptide (ANP), angiotensin II, aldosterone, and renin. Urine was analyzed for aquaporin-2 and PGE(2). Successful SD was achieved in all participants with a minimum of 4 h 50 min, and full-night SD was obtained in 50% of the participants. During SD, both boys and girls produced markedly larger amounts of urine than during normal sleep (477 ± 145 vs. 291 ± 86 ml, P < 0.01). SD increased urinary excretion of sodium (0.17 ± 0.05 vs. 0.10 ± 0.03 mmol·kg(-1)·h(-1)) whereas solute-free water reabsorption remained unchanged. SD induced a significant fall in nighttime plasma AVP (P < 0.01), renin (P < 0.05), angiotensin II (P < 0.001), and aldosterone (P < 0.05) whereas plasma ANP levels remained uninfluenced (P = 0.807). Nighttime blood pressure and heart rate were significantly higher during SD (mean arterial pressure: 78.5 ± 8.0 vs. 74.7 ± 8.7 mmHg, P < 0.001). SD leads to natriuresis and excess diuresis in healthy children. The underlying mechanism could be a reduced nighttime dip in blood pressure and a decrease in renin-angiotensin-aldosterone system levels during sleep deprivation.

  7. Postprandial and Orthostatic Hypotension Treated by Sitagliptin in a Patient with Dementia with Lewy Bodies

    PubMed Central

    Saito, Yoshihiro; Ishikawa, Joji; Harada, Kazumasa

    2016-01-01

    Patient: Female, 78 Final Diagnosis: Dementia with Lewy body Symptoms: Dizziness • sycope Medication: — Clinical Procedure: — Specialty: Geriatrics Objective: Unusual setting of medical care Background: Postprandial hypotension, induced by an absorption of glucose from intestine, could be treated by acarbose; however, it was unclear whether dipeptidyl peptidase-4 inhibitor reduced postprandial hypotension. Case Report: A 78-year-old woman who had experienced episodes of dizziness and hypotension after eating was admitted to our hospital. During 24-hour ambulatory blood pressure monitoring, there were repeated episodes of marked postprandial hypotension; i.e., a significant systolic blood pressure reduction within two hours after eating (from ‒58 to ‒64 mm Hg after meals). The patient was diagnosed with dementia with Lewy bodies. The patient exhibited postprandial hyperglycemia and hypotension after a 75 g oral glucose tolerance test. After the administration of 25 mg sitagliptin, the patient’s postprandial and orthostatic hypotension was reduced remarkably. Moreover, her Mini-Mental State Examination score subsequently increased (from 22 to 25 points). Conclusions: The dipeptidyl peptidase-4 inhibitor sitagliptin can delay postprandial increases in glucose levels and hypotensive episodes, as well as sympathetic nervous system abnormalities and orthostatic hypotension. PMID:27885251

  8. Five years of data diuresis: what have WEH learned?

    PubMed

    Sullivan, Jennifer C; Pollock, Jennifer S

    2015-11-01

    This year represents the fifth annual Data Diuresis session of the Water and Electrolyte Homeostasis (WEH) section of the American Physiological Society (APS) at the 2015 Experimental Biology meeting. As opposed to taking a single organ approach to the study of physiology, the WEH section employs an integrative approach to encompass how the different organ systems interact to regulate numerous physiological and pathophysiological processes. The goal of this minireview is to highlight the broad spectrum of research themes that were presented over the first five years of Data Diuresis. Presentation topics include (but are not limited to) oxidative stress, inflammation, obesity, pregnancy, and hypertension spanning the brain, heart and vasculature, and kidney. WEH researchers continue to impact and help drive the direction of physiological research across multiple disciplines, leaving us excited to see what the next five years of Data Diuresis will bring.

  9. Hypotension Begins at 110 mm Hg: Redefining Hypotension With Data

    DTIC Science & Technology

    2007-08-19

    would have potentially spinal, cardiogenic , tension pneumothoraxes, causes of shock . So we did not specifically isolate or exclude that subset. So...appropriately powered studies of hemorrhagic shock . Key Words: Hypotension, Shock , Trauma, Base deficit, Systolic blood pres- sure, Mortality. J Trauma...LeDran in 1743 from his reflection of experiences treating gunshot wounds.1 In 1872, Gross defined the shock state as “a manifestation of the rude

  10. Euglycemic Diabetic Ketoacidosis with Persistent Diuresis Treated with Canagliflozin

    PubMed Central

    Adachi, Junichiro; Inaba, Yuusuke; Maki, Chisato

    2017-01-01

    Diabetic ketoacidosis is characterized by hyperglycemia, anion-gap acidosis, and increased plasma ketones. After the resolution of hyperglycemia, persistent diuresis is rare. We herein report the case of a 27-year-old Asian woman with type 2 diabetes who was treated with a sodium-glucose cotransporter 2 (SGLT2) inhibitor (canagliflozin) who developed euglycemic diabetic ketoacidosis and persistent diuresis in the absence of hyperglycemia. Physicians should consider euglycemic diabetic ketoacidosis in the differential diagnosis of patients treated with SGLT2 inhibitors. PMID:28090050

  11. Euglycemic Diabetic Ketoacidosis with Persistent Diuresis Treated with Canagliflozin.

    PubMed

    Adachi, Junichiro; Inaba, Yuusuke; Maki, Chisato

    2017-01-01

    Diabetic ketoacidosis is characterized by hyperglycemia, anion-gap acidosis, and increased plasma ketones. After the resolution of hyperglycemia, persistent diuresis is rare. We herein report the case of a 27-year-old Asian woman with type 2 diabetes who was treated with a sodium-glucose cotransporter 2 (SGLT2) inhibitor (canagliflozin) who developed euglycemic diabetic ketoacidosis and persistent diuresis in the absence of hyperglycemia. Physicians should consider euglycemic diabetic ketoacidosis in the differential diagnosis of patients treated with SGLT2 inhibitors.

  12. On the mechanisms of kappa-opioid-induced diuresis.

    PubMed Central

    Blackburn, T. P.; Borkowski, K. R.; Friend, J.; Rance, M. J.

    1986-01-01

    In conscious saline loaded rats, the kappa-opioid agonists tifluadom, U50488, and ethylketocyclazocine, given subcutaneously, induced a characteristic diuresis which could be antagonized by naloxone. Bilateral adrenal demedullation significantly reduced adrenal gland catecholamine content and plasma adrenaline levels, but did not significantly affect plasma corticosterone levels, indicating that the adrenal cortex remained both intact and functional. Seven days following bilateral adrenal demedullation, the subcutaneous administration of the kappa-agonists no longer induced diuresis. However, demedullation did not affect the diuretic response to frusemide or clonidine, nor did it affect the antidiuretic response induced by the mu-opioid agonists morphine and buprenorphine. Adrenal catecholamines do not appear to be involved in kappa-opioid-induced diuresis, since pretreatment with propranolol, prazosin and idazoxan did not affect the diuretic response in intact animals. The results indicate a link between the adrenal medulla and kappa-opioid-induced diuresis and suggest that a peripheral mechanism may also be involved in mediating this effect. PMID:3542107

  13. On the mechanism of L-DOPA-induced postural hypotension in the cat

    PubMed Central

    Dhasmana, K. M.; Spilker, B. A.

    1973-01-01

    1. The effects of L-DOPA on postural hypotension and carotid occlusion pressor effect were studied, mainly in cats; the recovery of the blood pressure upon tilting was used as a measure of postural hypotension. 2. L-DOPA (30 mg/kg) partially depressed the carotid occlusion pressor effect and caused some degree of postural hypotension, L-DOPA (100 mg/kg) had more marked effects; the responses returned to control after 90 to 150 minutes. L-DOPA itself caused a pressor response in all cats. 3. The dopa decarboxylase inhibitor N1-(DL-seryl)-N2-(2,3,4-trihydroxybenzyl) hydrazine (RO4-4602, 50 and 10 mg/kg) had no effect itself on the tilt response but completely prevented the effects of L-DOPA on the carotid occlusion pressor effect and postural hypotension. 4. After RO4-4602 (3 and 1 mg/kg), L-DOPA (100 mg/kg) caused a brief rise of blood pressure followed by a longer lasting fall in horizontally-orientated cats (i.e. `supine' hypotension). No postural hypotension was observed after L-DOPA under these conditions. 5. Noradrenaline elicited only small and transient effects on postural hypotension, but dopamine's effects were more marked and longer lasting. Pressor dose-response relationships for noradrenaline were the same before and after L-DOPA, as well as in cats pretreated with L-DOPA for 4 days. 6. In cats with kidneys and intestines removed, the tilt reflex was still present. Dose-response curves to L-DOPA were the same as in normal animals. RO4-4602 (3 mg/kg) prevented postural hypotension and block of the carotid occlusion pressor effect; supine hypotension was also observed after L-DOPA. 7. The recovery response to tilting in spinal cats was markedly depressed or absent unless the blood pressure was elevated by angiotensin, in which experiments L-DOPA depressed the recovery upon tilting (i.e. induced postural hypotension). 8. Blood pressure responses to tyramine were increased after 10 mg/kg of L-DOPA, but depressed after 100 mg/kg. The response to tyramine was

  14. Osmotic and osmotic-loop diuresis in brain surgery. Effects on plasma and CSF electrolytes and ion excretion.

    PubMed

    Schettini, A; Stahurski, B; Young, H F

    1982-05-01

    In 22 patients to be operated on for brain tumors or cerebral aneurysms, the effect of osmotic diuresis was compared with that of osmotic-loop diuresis on plasma and cerebrospinal fluid (CSF) electrolytes, and water and ion excretion. Mannitol or mannitol plus furosemide were used to reduce brain bulk. After treatment with thiopental and hyperventilation, patients received randomly a rapid infusion of mannitol (1.4 gm/kg), or mannitol (1.4 gm/kg) plus furosemide (0.3 mg/kg). Brain shrinkage was considerably greater and more consistent with mannitol plus furosemide than with mannitol alone. However, hyponatremia, hypokalemia, hypochloremia, and hyperosmolality were also more marked (p less than 0.05) with mannitol plus furosemide than with mannitol. The rate of water and ion excretion was even more striking. At 30 minutes after absorption of mannitol alone, water excretion peaked at 17 ml/min, and gradually decreased to 3.8 ml/min 70 minutes later. With mannitol plus furosemide, during an identical time course, initial water excretion was 30 ml/min, followed by a further rise to 42 ml/min and then a decline to 17 ml/min. At peak diuresis after mannitol, Na+ and Cl- excretion average 0.57 and 0.62 mEq/min, respectively. This compares with mean values of 3.7 and 4.12 mEq/min for Na+ and Cl-, respectively, after mannitol plus furosemide. Although optimum brain shrinkage is achieved with osmotic-loop diuresis, the rapid electrolyte depletion (Na+ and Cl-) must be corrected to avoid altered sensorium during the patients' postoperative course.

  15. Alternating Skew Deviation from Traumatic Intracranial Hypotension

    PubMed Central

    Moster, Stephen J.; Moster, Mark L.

    2014-01-01

    Abstract A 56-year-old woman developed progressive headache, mental status changes, and diplopia after trauma. She was diagnosed with alternating skew deviation caused by intracranial hypotension. This is the first case of alternating skew deviation reported from intracranial hypotension and perhaps a differential pressure between intracranial and intraspinal spaces plays a role in the development of these findings. PMID:27928294

  16. Orthostatic hypotension: epidemiology, pathophysiology and management

    NASA Technical Reports Server (NTRS)

    Jacob, G.; Robertson, D.

    1995-01-01

    Orthostatic hypotension is characterized by low upright blood pressure levels and symptoms of cerebral hypoperfusion. Whereas orthostatic hypotension is heterogeneous, correct pathophysiologic diagnosis is important because of therapeutic and prognostic considerations. Although therapy is not usually curative, it can be extraordinarily beneficial if it is individually tailored. Management of the Shy-Drager syndrome (multiple-system atrophy) remains a formidable challenge.

  17. Regulation of arterial pressure: role of pressure natriuresis and diuresis.

    PubMed

    Hall, J E; Guyton, A C; Coleman, T G; Mizelle, H L; Woods, L L

    1986-12-01

    The importance of the renal pressure natriuresis and diuresis mechanisms in long-term control of body fluid volumes and arterial pressure has been controversial and difficult to quantitate experimentally. Recent studies, however, have demonstrated that in several forms of chronic hypertension caused by aldosterone, angiotensin II (AngII), vasopressin, or norepinephrine and adrenocorticotropin, increased renal arterial pressure is essential for maintaining normal excretion of sodium and water in the face of reduced renal excretory capability. When renal arterial pressure was servo-controlled in these models of hypertension, sodium and water retention continued unabated, causing ascites, pulmonary edema, or even complete circulatory collapse within a few days. Apparently, other mechanisms for volume homeostasis, such as the various natriuretic and diuretic factors that have been postulated, are not sufficiently powerful to maintain fluid balance in the absence of increased renal arterial pressure when renal excretory function is reduced in these forms of hypertension. The intrarenal mechanisms responsible for pressure natriuresis and diuresis are not entirely clear, but they seem to involve small increases in glomerular filtration rate and filtered load as well as reductions in fractional reabsorption in proximal and distal tubules. During chronic disturbances of arterial pressure additional factors, especially changes in AngII and aldosterone formation, act to amplify the effectiveness of the basic renal pressure natriuresis and diuresis mechanisms in regulating arterial pressure and body fluid volumes.

  18. Guidance document for structured reporting of diuresis renography.

    PubMed

    Taylor, Andrew T; Blaufox, M Donald; De Palma, Diego; Dubovsky, Eva V; Erbaş, Belkis; Eskild-Jensen, Anni; Frøkiær, Jørgen; Issa, Muta M; Piepsz, Amy; Prigent, Alain

    2012-01-01

    This Guidance Document for structured reporting of diuresis renography in adults was developed by the International Scientific Committee of Radionuclides in Nephro-urology (ISCORN; http://www.iscorn.org). ISCORN chose diuresis renography for its first structured report Guidance Document because suspected obstruction is the most common reason for referral, most radionuclide renal studies are conducted at institutions that perform fewer than 3 studies per week, and a large percentage of studies are interpreted by physicians with limited training in nuclear medicine. Ten panelists were asked to categorize specific reporting elements as essential, recommended, optional (without sufficient data to support a higher ranking), and unnecessary (does not contribute to scan interpretation or quality assurance). The final document was developed through an iterative series of comments and questionnaires with a majority vote required to place an element in a specific category. The Guidance Document recommends a reporting structure organized into indications, clinical history, study procedure, findings and impression and specifies the elements considered essential or recommended in each category. The Guidance Document is not intended to be restrictive but, rather, to provide a basic structure and rationale so that the diuresis renography report will: (1) communicate the results to the referring physician in a clear and concise manner designed to optimize patient care; (2) contain the essential elements required to evaluate and interpret the study; (3) clearly document the technical components of the study necessary for accountability, quality assurance and reimbursement; and (4) encourage clinical research by facilitating better comparison and extrapolation of results between institutions.

  19. Droxidopa in neurogenic orthostatic hypotension

    PubMed Central

    Kaufmann, Horacio; Norcliffe-Kaufmann, Lucy; Palma, Jose-Alberto

    2015-01-01

    Neurogenic orthostatic hypotension (nOH) is a fall in blood pressure on standing due to reduced norepinephrine release from sympathetic nerve terminals. nOH is a feature of several neurological disorders that affect the autonomic nervous system, most notably Parkinson disease (PD), multiple system atrophy, pure autonomic failure and other autonomic neuropathies. Droxidopa, an orally active synthetic amino acid that is converted to norepinephrine by the enzyme aromatic L-amino acid decarboxylase (dopa-decarboxylase), was recently approved by the FDA for the short-term treatment of nOH. It is presumed to raise blood pressure by acting at the neurovascular junction to increase vascular tone. This review summarizes the pharmacological properties of droxidopa, its mechanism of action, and the efficacy and safety results of clinical trials. PMID:26092297

  20. Sympathoinhibition and hypotension in carotid sinus hypersensitivity

    NASA Technical Reports Server (NTRS)

    Smith, M. L.; Ellenbogen, K. A.; Eckberg, D. L.

    1992-01-01

    Carotid sinus reflex hypersensitivity is a known cause of syncope in humans. The condition is characterized by cardioinhibition and vasodepression, each to varying degrees. The extent and importance of sympathoinhibition has not been determined in patients with carotid sinus hypersensitivity. This study reports on the extent of sympathoinhibition measured directly directly during carotid massage with and without atrioventricular sequential pacing, in a patient with symptomatic carotid sinus reflex hypersensitivity. Carotid massage elicited asystole, hypotension and complete inhibition of muscle sympathetic nerve activity. Carotid massage during atrioventricular pacing produced similar sympathoinhibition, but with minimal hypotension. Therefore, sympathoinhibition did not contribute importantly to the hypotension during carotid massage in the supine position in this patient. Further investigations are required to elucidate the relation of sympathoinhibition to hypotension in patients with carotid sinus hypersensitivity in the upright position.

  1. [Orthostatic hypotension in the elderly].

    PubMed

    Ferrer-Gila, Teresa; Rízea, Cristian

    2013-03-16

    Orthostatic hypotension (OH) is defined as a decrease in systolic blood pressure of 20 mmHg, or a decrease in diastolic blood pressure of 10 mmHg within three minutes of standing. It results from an inadequate response to postural changes in blood pressure. Common symptoms include dizziness, light-headedness, blurred vision, weakness, fatigue, nausea, palpitations, sweating, head and neck ache, slow cognitive performance and transient loss of conscientiousness. OH is a common problem among elderly patients and its aetiology is diverse, including autonomic nervous system dysfunction, cardiac problems, medication side effects, ageing changes or transitory deregulation of blood volume. The instrumental diagnosis can be easily accomplished by the tilt-table test, with continuous monitoring of blood pressure and cardiac parameters. It is a non-invasive technique and needs minimal collaboration from the patient. In our experience, when reviewing 327 patients, aged over 40 years and examined because of clinical suspicion of OH, the prevalence thereof was 51% whereas if focused in subjects older than 70, OH was proven in 90% of the cases. The older the patients, the more frequently they presented general deterioration, neurological or cardiac problems as well as pharmacological side effects. Ruling out neurological or cardiac malfunction can drastically improve the prognosis with possible reversibility of symptoms. Some nonpharmacological and pharmacological approaches to improve management of OH and life quality are described for guidance.

  2. Orthostatic Hypotension: Mechanisms, Causes, Management

    PubMed Central

    Tomalia, Victoria A.

    2015-01-01

    Orthostatic hypotension (OH) occurs when mechanisms for the regulation of orthostatic BP control fails. Such regulation depends on the baroreflexes, normal blood volume, and defenses against excessive venous pooling. OH is common in the elderly and is associated with an increase in mortality rate. There are many causes of OH. Aging coupled with diseases such as diabetes and Parkinson's disease results in a prevalence of 10-30% in the elderly. These conditions cause baroreflex failure with resulting combination of OH, supine hypertension, and loss of diurnal variation of BP. The treatment of OH is imperfect since it is impossible to normalize standing BP without generating excessive supine hypertension. The practical goal is to improve standing BP so as to minimize symptoms and to improve standing time in order to be able to undertake orthostatic activities of daily living, without excessive supine hypertension. It is possible to achieve these goals with a combination of fludrocortisone, a pressor agent (midodrine or droxidopa), supplemented with procedures to improve orthostatic defenses during periods of increased orthostatic stress. Such procedures include water bolus treatment and physical countermaneuvers. We provide a pragmatic guide on patient education and the patient-orientated approach to the moment to moment management of OH. PMID:26174784

  3. [Role of prostaglandin E2 in regulation of urine excretion in saluresis, water and osmotic diuresis in rat].

    PubMed

    Bogolepova, A E; Shakhmatova, E I

    2004-11-01

    In the saluresis, water and osmotic diuresis were indicating an increase of prostaglandin E2 excretion and a correlation between this index and diuresis. Unselective blockade of cyclooxygenase by diclofenac-natrium leads to a decrease of diuresis in the observed types of urine-production in rats. Inhibition of inducible cyclooxygenase by celebrex didn't change the value of diuresis after water load or administration of osmotic agent, but decreased the diuretic effect of furosemide.

  4. Lysosphingolipid receptor-mediated diuresis and natriuresis in anaesthetized rats.

    PubMed

    Bischoff, A; Meyer Zu Heringdorf, D; Jakobs, K H; Michel, M C

    2001-04-01

    Lysosphingolipids such as sphingosine-1-phosphate (SPP) and sphingosylphosphorylcholine (SPPC) can act on specific G-protein-coupled receptors. Since SPP and SPPC cause renal vasoconstriction, we have investigated their effects on urine and electrolyte excretion in anaesthetized rats. Infusion of SPP (1 - 30 microg kg(-1) min(-1)) for up to 120 min dose-dependently but transiently (peak after 15 min, disappearance after 60 min) reduced renal blood flow without altering endogenous creatinine clearance. Nevertheless, infusion of SPP increased diuresis, natriuresis and calciuresis and, to a lesser extent, kaliuresis. These tubular lysosphingolipid effects developed more slowly (maximum after 60 - 90 min) and also abated more slowly upon lysosphingolipid washout than the renovascular effects. Infusion of SPPC, sphingosine and glucopsychosine (3 - 30 microg kg(-1) min(-1) each) caused little if any alterations in renal blood flow but also increased diuresis, natriuresis and calciuresis and, to a lesser extent, kaliuresis. Pretreatment with pertussis toxin (10 microg kg(-1) 3 days before the acute experiment) abolished the renovascular and tubular effects of 30 microg kg(-1) min(-1) SPP. These findings suggest that lysosphingolipids are a hitherto unrecognized class of endogenous modulators of renal function. SPP affects renovascular tone and tubular function via receptors coupled to G(i)-type G-proteins. SPPC, sphingosine and glucopsychosine mimic only the tubular effects of SPP, and hence may act on distinct sites.

  5. Sex differences in pressure diuresis/natriuresis in rabbits.

    PubMed

    Evans, R G; Stevenson, K M; Bergström, G; Denton, K M; Madden, A C; Gribben, R L; Weekes, S R; Anderson, W P

    2000-08-01

    We tested for sex-related differences in the pressure diuresis/natriuresis relationships in anaesthetized, renally denervated rabbits, using an extracorporeal circuit to perfuse the left kidney with the rabbit's own blood, through a series of step-wise increases in renal artery pressure (RAP) (from 65 to 130 mmHg). Urine flow, sodium excretion, and the fractional excretions of sodium and urine increased with increasing RAP, and were greater in male than in female rabbits at all levels of RAP-tested. However, these apparent sex-related differences in the acute pressure diuresis/natriuresis relationships were not reflected in alterations in chronic regulation of mean arterial pressure (MAP). Thus, in rabbits on a normal salt diet (0.85 g day(-1)), resting conscious MAP was significantly greater in males (87 +/- 3 mmHg) compared with females (77+/-1 mmHg). Chronically increasing daily salt intake to 4.98 g day(-1) for 28 days had no significant effect on resting conscious MAP in either sex. Thus, although our observations indicate sex differences, at least under the present experimental conditions, in the factors regulating extracellular fluid volume, these do not appear to have a major impact in setting the level of MAP in the long term.

  6. Hyperprolactinemia due to spontaneous intracranial hypotension.

    PubMed

    Schievink, Wouter I; Nuño, Miriam; Rozen, Todd D; Maya, M Marcel; Mamelak, Adam N; Carmichael, John; Bonert, Vivien S

    2015-05-01

    OBJECT Spontaneous intracranial hypotension is an increasingly recognized cause of headaches. Pituitary enlargement and brain sagging are common findings on MRI in patients with this disorder. The authors therefore investigated pituitary function in patients with spontaneous intracranial hypotension. METHODS Pituitary hormones were measured in a group of 42 consecutive patients with spontaneous intracranial hypotension. For patients with hyperprolactinemia, prolactin levels also were measured following treatment. Magnetic resonance imaging was performed prior to and following treatment. RESULTS The study group consisted of 27 women and 15 men with a mean age at onset of symptoms of 52.2 ± 10.7 years (mean ± SD; range 17-72 years). Hyperprolactinemia was detected in 10 patients (24%), ranging from 16 ng/ml to 96.6 ng/ml in men (normal range 3-14.7 ng/ml) and from 31.3 ng/ml to 102.5 ng/ml in women (normal range 3.8-23.2 ng/ml). In a multivariate analysis, only brain sagging on MRI was associated with hyperprolactinemia. Brain sagging was present in 60% of patients with hyperprolactinemia and in 19% of patients with normal prolactin levels (p = 0.02). Following successful treatment of the spontaneous intracranial hypotension, hyperprolactinemia resolved, along with normalization of brain MRI findings in all 10 patients. CONCLUSIONS Spontaneous intracranial hypotension is a previously undescribed cause of hyperprolactinemia. Brain sagging causing distortion of the pituitary stalk (stalk effect) may be responsible for the hyperprolactinemia.

  7. Studies on the adrenomedullary dependence of kappa-opioid agonist-induced diuresis in conscious rats.

    PubMed Central

    Borkowski, K. R.

    1989-01-01

    1. The dependence of kappa-opioid agonist-induced diuresis, upon an intact and functional adrenal medulla in conscious rats, was investigated in order to test the hypothesis that the diuresis is mediated by a blood-borne 'diuretic factor', of adrenomedullary origin, released by kappa-opioid receptor stimulation. 2. Confirming previous observations, adrenal demedullation significantly attenuated diuretic responses to the kappa-opioid agonists U50488H, ethylketocyclazocine (EKC) and tifluadom, but did not affect basal urine output, furosemide-induced diuresis or the antidiuretic response to the mu-opioid agonist, buprenorphine. Naloxone abolished U50488H-induced diuresis, confirming an involvement of opioid receptors. 3. Transfusion studies established that blood, from intact rats treated with U50488H, induced diuresis in intact and demedullated recipient rats, whether or not the recipients had been pretreated with naloxone. However, blood from demedullated rats treated with U50448H was unable to induce diuresis when administered to intact or demedullated recipients. 4. It is concluded that kappa-opioid agonist-induced diuresis is dependent upon an intact and functional adrenal medulla and appears to be mediated by a blood-borne 'diuretic factor' of adrenomedullary origin. PMID:2558758

  8. Genetics and molecular biology of hypotension

    NASA Technical Reports Server (NTRS)

    Robertson, D.

    1994-01-01

    Major strides in the molecular biology of essential hypertension are currently underway. This has tended to obscure the fact that a number of inherited disorders associated with low blood pressure exist and that these diseases may have milder and underrecognized phenotypes that contribute importantly to blood pressure variation in the general population. This review highlights some of the gene products that, if abnormal, could cause hypotension in some individuals. Diseases due to abnormalities in the catecholamine enzymes are discussed in detail. It is likely that genetic abnormalities with hypotensive phenotypes will be as interesting and diverse as those that give rise to hypertensive disorders.

  9. A C-terminal Aldehyde Analog of the Insect Kinins Inhibits Diuresis in the Housefly

    DTIC Science & Technology

    2006-09-21

    p e p t i d e s 2 8 ( 2 0 0 7 ) 1 4 6 – 1 5 2A C-terminal aldehyde analog of the insect kinins inhibits diuresis in the housefly Ronald J. Nachman a...secretion in crickets, but shows inhibition of both in vitro and in vivo diuresis in the housefly. R-LK-CHO reduced the total amount of urine voided over 3 h...to stimulate Malpighian tubule fluid secretion [2,25]. In the housefly, muscakinin has been implicated in the control of diuresis in response to

  10. Orthostatic Hypotension (Low Blood Pressure) and Parkinson's Disease

    MedlinePlus

    ... Impulsive Behaviors Orthostatic Hypotension (Low Blood Pressure) Pain Skeleton and Bone Health: Orthopedics and Parkinson’s Skin Changes ... Impulsive Behaviors Orthostatic Hypotension (Low Blood Pressure) Pain Skeleton and Bone Health: Orthopedics and Parkinson’s Skin Changes ...

  11. [MRI evaluation of cervicothoracic CSF hypotension].

    PubMed

    Maraval, A; Brugieres, P; Combes, C; Thomas, P; Blanc, R; Gaston, A

    2006-06-01

    We propose studying signs of cervicothoracic CSF hypotension by MRI. Axial T1-weighted GRE sequence with and without saturation bands positioned above and below the selected image plane, MR venography and MR Angiography with contrast administration are helpful to confirm the venous nature of the epidural thickening and to make the differential diagnosis with infectious or neoplastic epiduritis.

  12. RNAi-mediated gene knockdown and in vivo diuresis assay in adult female Aedes aegypti mosquitoes.

    PubMed

    Drake, Lisa L; Price, David P; Aguirre, Sarah E; Hansen, Immo A

    2012-07-14

    This video protocol demonstrates an effective technique to knockdown a particular gene in an insect and conduct a novel bioassay to measure excretion rate. This method can be used to obtain a better understanding of the process of diuresis in insects and is especially useful in the study of diuresis in blood-feeding arthropods that are able to take up huge amounts of liquid in a single blood meal. This RNAi-mediated gene knockdown combined with an in vivo diuresis assay was developed by the Hansen lab to study the effects of RNAi-mediated knockdown of aquaporin genes on Aedes aegypti mosquito diuresis. The protocol is setup in two parts: the first demonstration illustrates how to construct a simple mosquito injection device and how to prepare and inject dsRNA into the thorax of mosquitoes for RNAi-mediated gene knockdown. The second demonstration illustrates how to determine excretion rates in mosquitoes using an in vivo bioassay.

  13. Hypotension and hypovolemia during hemodialysis: is the usual suspect innocent?

    PubMed

    Berger, David; Takala, Jukka

    2016-06-09

    Hypotension during intermittent hemodialysis is common, and has been attributed to acute volume shifts, shifts in osmolarity, electrolyte imbalance, temperature changes, altered vasoregulation, and sheer hypovolemia. Although hypovolemia may intuitively seem a likely cause for hypotension in intensive care patients, its role in the pathogenesis of intradialytic hypotension may be overestimated.

  14. [Renal urodilatin secretion is associated with diuresis and natriuresis after spontaneous, supraventricular tachycardia].

    PubMed

    Kentsch, M; Kuhrmann, T; Drummer, C; Rodemerk, U; Gerzer, R; Müller-Esch, G

    1998-02-01

    Patients with paroxysmal supraventricular tachycardia (SVT) may have a polyuria after termination of tachycardia. There is increasing evidence that the renal peptide urodilatin (ANP (95-126))--and not plasma ANP (ANP (99-126))--is the member of the natriuretic peptide family mediating natriuresis and diuresis in man. In patients with SVT we, therefore, analyzed the relationship between diuresis, natriuresis, plasma ANP, urinary urodilatin excretion and renal excretion of cyclic GMP, the second messenger in the ANP system. During and after clinical presentation with spontaneously occurring SVT, two patients with AV-nodal and one patient with atrioventricular reentry tachycardia (heart rate 160 to 200 bpm) were studied. Urinary urodilatin excretion was correlated to diuresis (r = 0.73) and natriuresis (r = 0.93); similarly urinary cyclic GMP excretion was related to diuresis (r = 0.80) and natriuresis (r = 0.87; p < 0.001, respectively). In contrast, there was no significant correlation between plasma ANP concentrations and diuresis (r = 0.28, n.s.) or natriuresis (r = 0.11, n.s.). As an explorative analysis, stepwise multiple linear regression identified urinary urodilatin as the most important contributor to diuresis and natriuresis after SVT. These data on polyuria after spontaneous SVT further support the view that in man urodilatin is the member of the natriuretic peptide family participating in kidney physiology.

  15. Retrospective study to characterize post-obstructive diuresis in cats with urethral obstruction.

    PubMed

    Francis, Brenda J; Wells, Raegan J; Rao, Sangeeta; Hackett, Timothy B

    2010-08-01

    Urethral obstruction is a common medical emergency in cats. Frequency of post-obstruction diuresis in cats following resolution of urethral obstruction is unknown. The objective of this study was to document frequency and associated clinical features of post-obstruction diuresis in cats. The records of 32 cats undergoing 33 admissions to the Colorado State University Veterinary Hospital for urethral obstruction were reviewed. Signalment, admission blood values, fluid therapy, and urine output were recorded. Diuresis was defined as urine output greater than 2ml/kg/h. Post-obstructive diuresis occurred in 46% (13/28) of cats within the first 6h of treatment. Occurrence of post-obstructive diuresis was statistically more likely in cats with venous pH<7.35 on admission. Urine production following resolution of urethral obstruction should be monitored so that fluid therapy can be adjusted to the individual patient, as many cats will have a higher fluid requirement secondary to post-obstruction diuresis.

  16. Does training-induced orthostatic hypotension result from reduced carotid baroreflex responsiveness?

    NASA Technical Reports Server (NTRS)

    Pawelczyk, James A.; Raven, Peter B.

    1994-01-01

    As manned space travel has steadily increased in duration and sophistication, the answer to a simple, relevant question remains elusive. Does endurance exercise training - high intensity rhythmic activity, performed regularly for extended periods of time - alter the disposition to, or severity of, postflight orthostatic hypotension? Research results continue to provide different views; however, data are difficult to compare because of the following factors that vary between investigations: the type of orthostatic stress imposed (+Gz, lower body negative pressure (LBNP), head-up tilt); pretest perturbations used (exercise, heat exposure, head-down tilting, bed rest, water immersion, hypohydration, pharmacologically-induced diuresis); the length of the training program used in longitudinal investigations (days versus weeks versus months); the criteria used to define fitness; and the criteria used to define orthostatic tolerance. Generally, research results indicate that individuals engaged in aerobic exercise activities for a period of years have been reported to have reduced orthostatic tolerance compared to untrained control subjects, while the results of shorter term longitudinal studies remain equivocal. Such conclusions suggest that chronic athletic training programs reduce orthostatic tolerance, whereas relatively brief (days to weeks) training programs do not affect orthostatic tolerance to any significant degree (increase or decrease). A primary objective was established to identify the alterations in blood pressure control that contribute to training-induced orthostatic hypotension (TIOH). Although any aspect of blood pressure regulation is suspect, current research has been focused on the baroreceptor system. Reductions in carotid baroreflex responsiveness have been documented in exercise-trained rabbits, reportedly due to an inhibitory influence from cardiac afferent, presumably vagal, nerve fibers that is abolished with intrapericardiac denervation. The

  17. Stretch Marks

    MedlinePlus

    ... like during puberty), that person may get fine lines on the body called stretch marks. Stretch marks happen when the skin is pulled by rapid growth or stretching. Although the skin is usually fairly elastic, when it's overstretched, the normal production of collagen (the major protein that makes up ...

  18. A dynamic paracellular pathway serves diuresis in mosquito Malpighian tubules.

    PubMed

    Beyenbach, Klaus W

    2012-07-01

    Female mosquitoes gorge on vertebrate blood, a rich nutrient source for developing eggs, but gorging meals increase the risk of predation. Mosquitoes are quick to reduce the flight payload with a potent diuresis. Diuretic peptides of the insect kinin family induce a tenfold reduction in the paracellular resistance of Malpighian tubules and increase the paracellular permeation of Cl(-), the counterion of the transepithelial secretion of Na(+) and K(+). As a result, the transepithelial secretion of NaCl and KCl and water increases. Insect kinins signal the opening of the paracellular pathway via G protein-coupled receptors and the elevation of intracellular [Ca(2+)], which leads to the reorganization of the cytoskeleton associated with the septate junction (SJ). The reorganization may affect the septate junctional proteins that control the barrier and permselectivity properties of the paracellular pathway. The proteins involved in the embryonic formation of the SJ and in epithelial polarization are largely known for ectodermal epithelia, but the proteins that form and mediate the dynamic functions of the SJ in Malpighian tubules remain to be determined.

  19. Hemodilution, vasopressin suppression, and diuresis during water immersion in man

    NASA Technical Reports Server (NTRS)

    Greenleaf, J. E.; Keil, L. C.; Shvartz, E.

    1981-01-01

    The possible role of hemodilution in the early stages of water immersion in the suppression of antidiuretic hormone (vasopressin) and subsequent diuresis in man is investigated. Parameters characterizing hemodilution as well as water balance and intercompartmental fluid levels were measured before, during and after the immersion of ten subjects in a semireclining position in tap water up to their necks at 34.6 C for 8 hr. Results indicate that hemodilution and the suppression of vasopressin and plasma renin activity were present by the second hour of immersion, with the early hemodilution due to a slight increase in plasma volume with no change in plasma sodium or osmotic contents, even though urine volume and osmotic excretion rates increased significantly. Hyponatremia, hyposmotemia and plasma renin activity suppression are observed to continue to the end of immersion, resulting in final decreases of 15.6% in plasma volume, 18.8% in extracellular volume, 19.6% in interstitial volume and 10.7% in red cell volume. Findings suggest the transfer of hypotonic fluid into the vascular system, which contributes to vasopressin suppression observed during immersion.

  20. [Orthostatic hypotension: an unusual manifestation of pheochromocytoma].

    PubMed

    Tagle, Rodrigo; Acosta, Pamela; Valdés, Gloria

    2003-12-01

    Pheochromocytoma, though an uncommon cause of hypertension, can be a lethal condition. Because of this it is mandatory to diagnose it or rule it out in presence of suggestive symptoms. Typical symptoms are palpitations, sweating, severe headaches and hypertension. However, there are other suggestive symptoms of this dangerous endocrine entity, one of which is the orthostatic hypotension. We report the case of a 65 years old female patient with long standing hypertension in whom the pheochromocytoma was suspected after episodes of orthostatic hypotension. Although this manifestation was described almost fifty years ago, its frequency and pathophysiology has not yet been well established and fully elucidated. Moreover, it has meaningful implications in relation to preoperatory management and the timing of surgery.

  1. Severe bradycardia and prolonged hypotension in ciguatera.

    PubMed

    Chan, Thomas Yan Keung

    2013-06-01

    Ciguatera results when ciguatoxin-contaminated coral reef fish from tropical or subtropical waters are consumed. The clinical features that present in affected persons are mainly gastrointestinal, neurological, general, and much less commonly, cardiovascular. We report the case of a 50-year-old man who developed the characteristic combination of acute gastrointestinal and neurological symptoms after the consumption of an unidentified coral reef fish head. In addition to those symptoms, he developed dizziness, severe bradycardia (46 bpm) and prolonged hypotension, which required the administration of intravenous atropine and over three days of intravenous fluid replacement with dopamine infusion. Patients with ciguatera can develop severe bradycardia and prolonged hypotension. Physicians should recognise the possible cardiovascular complications of ciguatera and promptly initiate treatment with intravenous atropine, intravenous fluid replacement and inotropic therapy if such complications are observed.

  2. Marking Time

    ERIC Educational Resources Information Center

    Foster, Colin

    2011-01-01

    Teachers say that they would gladly teach a day in the classroom if at the end of the day they could leave and have no marking. There is a common staffroom perception that mathematics teachers have it easy when it comes to marking. In arts subjects, setting an essay can be a fairly straightforward matter--a one-line question may suffice--but…

  3. Effect of sertraline hydrochloride on dialysis hypotension.

    PubMed

    Dheenan, S; Venkatesan, J; Grubb, B P; Henrich, W L

    1998-04-01

    Hemodialysis hypotension (HH) is a very common disorder and has a multifactorial etiology. Autonomic dysfunction occurs in up to 50% of patients with end-stage renal disease (ESRD) and plays a key role in HH in some patients. Sertraline hydrochloride, a central nervous system serotonin reuptake inhibitor, has been shown to be an effective treatment of hypotension caused by autonomic dysfunction in disorders such as neurocardiogenic syncope and idiopathic orthostatic hypotension. This study sought to determine whether sertraline was effective in ameliorating HH. A retrospective chart analysis was performed that included nine consecutive patients (aged > or = 54 years, time on hemodialysis > or = 2.2 years) placed on sertraline (50 to 100 mg/d) for depression who also had HH (defined as prehemodialysis systolic blood pressure [SBP] < or = 100 mm Hg, > or = 40 mm Hg decrease in SBP during hemodialysis, SBP <90 mm Hg, any diastolic blood pressure <40 mm Hg, or a decrease in blood pressure-causing symptoms) before treatment with sertraline. The data from a 6-week pre-sertraline period were compared with the data from a 6-week sertraline period (defined as 6 weeks after drug begun). Blood pressure medications were unchanged during the trial period of sertraline. However, nadir mean arterial pressure recorded during a given dialysis session in the pre-sertraline period (55+/-4 mm Hg) was significantly lower than that recorded in the sertraline period (68+/-5 mm Hg; P < 0.05). In addition, the number of hypotensive episodes (same definition as HH) per dialysis session during the sertraline period was significantly lower than that during the pre-sertraline period (mean, 0.6+/-0.2 episodes per session v 1.4+/-0.3 episodes per session; P < 0.005). The number of therapeutic interventions required for hypotension during the sertraline period was also significantly less than that during the pre-sertraline period (mean, 1.7+/-0.8 interventions v 11.0+/-3.0 interventions; P < 0

  4. Effect of interactions between nitric oxide and angiotensin II on pressure diuresis and natriuresis.

    PubMed

    Madrid, M I; García-Salom, M; Tornel, J; De Gasparo, M; Fenoy, F J

    1997-11-01

    The present study examined the effect of an angiotensin II AT1 or AT2 receptor antagonist on the impairment of the pressure diuresis and natriuresis response produced by nitric oxide (NO) synthesis blockade. N omega-nitro-L-arginine methyl ester (L-NAME, 37 nmol.kg-1.min-1) lowered renal blood flow and reduced the slopes of the pressure diuresis and natriuresis responses by 44 and 40%, respectively. Blockade of AT1 receptors with valsartan increased slightly sodium and water excretion at low renal perfusion pressure (RPP). Blockade of AT2 receptors with PD-123319 had no effect on renal function. The administration of valsartan or PD-123319 to rats given L-NAME had no effect on the renal vasoconstriction induced by NO synthesis blockade. In addition, in rats given L-NAME, valsartan elevated baseline excretory values at all RPP studied, but it had no effect on the sensitivity of the pressure diuresis and natriuresis response. However, the administration of PD-123319 to L-NAME-pretreated rats shifted the slopes of the pressure diuresis and natriuresis responses toward control values, indicating that the impairment produced by NO synthesis blockade on pressure diuresis is dependent on the activation of AT2 angiotensin receptors.

  5. Medial prefrontal cortex acetylcholine injection-induced hypotension: the role of hindlimb vasodilation

    NASA Technical Reports Server (NTRS)

    Crippa, G. E.; Lewis, S. J.; Johnson, A. K.; Correa, F. M.

    2000-01-01

    The injection of acetylcholine (ACh) into the cingulate region of the medial prefrontal cortex (MPFC) causes a marked fall in arterial blood pressure which is not accompanied by changes in heart rate. The purpose of the present study was to investigate the hemodynamic basis for this stimulus-induced hypotension in Sprague-Dawley rats. The study was designed to determine whether a change in the vascular resistance of hindlimb, renal or mesenteric vascular beds contributes to the fall in arterial pressure in response to ACh injection into the cingulate cortex. Miniature pulsed-Doppler flow probes were used to measure changes in regional blood flow and vascular resistance. The results indicated that the hypotensive response was largely due to a consistent and marked vasodilation in the hindlimb vascular bed. On this basis, an additional experiment was then undertaken to determine the mechanisms that contribute to hindlimb vasodilation. The effect of interrupting the autonomic innervation of one leg on the hindlimb vasodilator response was tested. Unilateral transection of the lumbar sympathetic chain attenuated the cingulate ACh-induced vasodilation in the ipsilateral, but not in the contralateral hindlimb. These results suggest that the hypotensive response to cingulate cortex-ACh injection is caused by skeletal muscle vasodilation mediated by a sympathetic chain-related vasodilator system.

  6. Dopamine-resistant hypotension and severe retinopathy of prematurity

    PubMed Central

    Catenacci, Melissa; Miyagi, Shogo; Wickremasinghe, Andrea C.; Lucas, Sarah Scarpace; de Alba Campomanes, Alejandra G.; Good, William V.; Clyman, Ronald I.

    2013-01-01

    Objective To examine the relationship between the cause or severity of hypotension and the development of severe retinopathy of prematurity (sROP) (≥ stage 3 or stage 2 with plus disease in Zone I or II).. Study design Infants (<28 weeks’ gestation, n=242) were observed for hypotension and treated with a standardized hypotension-treatment protocol. Hypotension was classified as resulting from one of the following causes: (a) culture-positive infection and/or necrotizing enterocolitis, (b) PDA ligation, or (c) “idiopathic” (no cause identified other than prematurity), and as being either dopamine-responsive or dopamine-resistant. Cortisol levels were measured for infants with dopamine-resistant hypotension. Eye examinations were performed until the ROP resolved or the vasculature matured. Multivariable logistic regression analysis was performed to determine the relationship between the cause/severity of hypotension and sROP. Results Overall, 66% of infants developed hypotension (41% were dopamine-responsive and 25% were dopamine-resistant). sROP developed in 19% of infants. “Idiopathic” dopamine-resistant hypotension was the only cause significantly related to sROP. 66% of infants with dopamine-resistant hypotension had low serum cortisol (≤10 μg/dL). Low cortisol, in the presence of dopamine-resistant hypotension, was significantly associated with sROP and accounted for the relationship between “idiopathic” hypotension and sROP. When low cortisol was included in statistical models, other known risk factors, such as immature gestation, were no longer significantly related to sROP. Conclusion Low cortisol, in the presence of dopamine-resistant hypotension, has the greatest magnitude of association with sROP. PMID:23465406

  7. Pharmacology of Casimiroa edulis IV. Hypotensive effects of compounds isolated from methanolic extracts in rats and guinea pigs.

    PubMed

    Magos, G A; Vidrio, H; Reynolds, W F; Enríquez, R G

    1999-01-01

    Bioassay-directed fractionation of the methanolic extract of seeds of Casimiroa edulis led to the isolation of seven constituents with cardiovascular activity, namely the new compound synephrine acetonide and the known compounds N-monomethylhistamine, N,N-dimethylhistamine, proline, N-methylproline, gamma-aminobutyric acid and casimiroedine. In anesthetized rats, both histamine derivatives produced transient hypotension mediated via H1-histaminergic receptors and in the case of N,N-dimethylhistamine, via nitric oxide release. Synephrine acetonide produced transient hypertension and tachycardia, mediated via alpha- and alpha- and beta-adrenergic receptores, respectively. The chromatographic zone containing N-methyproline, proline and gamma-aminobutyric acid elicited marked and prolonged hypotension. Finally, casimiroedine did not modify the blood pressure of anesthetized rats, but lowered it persistently in anesthetized guinea pigs. It was concluded that hypotension produced by C. edulis is due to several active components. The immediate effect can be attributed to the histamine derivatives acting on H1-receptors. More prolonged hypotension would be produced by the mixture of amino acids through an unknown mechanism, as well as by casimiroedine, possibly by activation of H3-receptors. Hypotension is partially offset by synephrine acetonide through adrenergic mechanisms.

  8. Alanine increases blood pressure during hypotension

    NASA Technical Reports Server (NTRS)

    Conlay, L. A.; Maher, T. J.; Wurtman, R. J.

    1990-01-01

    The effect of L-alanine administration on blood pressure (BP) during haemorrhagic shock was investigated using anesthetized rats whose left carotid arteries were cannulated for BP measurement, blood removal, and drug administration. It was found that L-alanine, in doses of 10, 25, 50, 100, and 200 mg/kg, increased the systolic BP of hypotensive rats by 38 to 80 percent (while 100 mg/kg pyruvate increased BP by only 9.4 mmhg, not significantly different from saline). The results suggest that L-alanine might influence cardiovascular function.

  9. Orthostatic hypotension. Causes, evaluation, and management.

    PubMed Central

    Hollister, A S

    1992-01-01

    Chronic orthostatic hypotension is caused by a variety of disorders. Frequently patients withdraw from social interactions, are prone to adverse drug reactions and inappropriate diagnoses, and are bed-bound by the time of diagnosis. Applying basic principles of cardiovascular physiology and pharmacology usually permits these patients to lead active lives and to live longer. Much of the management is based on common sense and knowledge of the basic pathophysiology of the disorder and depends on thorough patient education and close monitoring of blood pressure in many of the activities of daily living. PMID:1475949

  10. Interactions between nitric oxide and renal nerves on pressure-diuresis and natriuresis.

    PubMed

    Madrid, M I; Salom, M G; Tornel, J; López, E; Fenoy, F J

    1998-09-01

    The present study examined the effect of renal denervation on the impairment of the pressure-diuresis response produced by nitric oxide synthesis blockade. The experiments were performed in Inactin-anesthetized Munich-Wistar rats. The animals with innervated kidneys had lower baseline values of renal blood flow, GFR, sodium excretion (UNaV), and urine flow (V) than rats with denervated kidneys. Also, renal denervation shifted pressure-diuresis and natriuresis toward lower pressures. A low dose of N(omega)-nitro-L-arginine methyl esther (NAME, 3.7 nmol/kg per min) reduced UNaV and the fractional excretion of sodium (FENa) and blunted pressure-natriuresis only in rats with innervated kidneys, whereas it had no effects in rats with denervated kidneys. A medium dose of NAME (37 nmol/kg per min) lowered FENa only in rats with innervated kidneys. The administration of NAME (37 nmol/kg per min) blunted pressure-diuresis and natriuresis in kidneys with or without the renal nerves, but the effect was more pronounced in rats with innervated kidneys. A high dose of NAME (3.7 micromol + 185 nmol/kg per min) increased UNaV and FENa only in rats with innervated kidneys, whereas it reduced GFR, V, UnaV, and FENa in rats with denervated kidneys. However, pressure-natriuresis and diuresis were blunted by this high dose of NAME independently of the presence or absence of renal nerves. These results demonstrate that renal nerves potentiate the renal effects of low doses of NAME on renal function and pressure-diuresis and natriuresis. However, high doses of NAME abolish pressure-diuresis independently of renal nerves, and the natriuretic effect of NAME in innervated kidneys may be attributed to reflex inhibition of sympathetic tone due to the rise in arterial pressure.

  11. Pathophysiology of the Cardiovascular System and Neonatal Hypotension.

    PubMed

    Shead, Sandra L

    2015-01-01

    Hypotension is common in low birth weight neonates and less common in term newborns and is associated with significant morbidity and mortality. Determining an adequate blood pressure in neonates remains challenging for the neonatal nurse because of the lack of agreed-upon norms. Values for determining norms for blood pressure at varying gestational and postnatal ages are based on empirical data. Understanding cardiovascular pathophysiology, potential causes of hypotension, and assessment of adequate perfusion in the neonatal population is important and can assist the neonatal nurse in the evaluation of effective blood pressure. This article reviews cardiovascular pathophysiology as it relates to blood pressure and discusses potential causes of hypotension in the term and preterm neonate. Variation in management of hypotension across centers is discussed. Underlying causes and pathophysiology of hypotension in the neonate are described.

  12. Bradykinin may be involved in neuropeptide Y-induced diuresis, natriuresis, and calciuresis.

    PubMed

    Bischoff, A; Rascher, W; Michel, M C

    1998-10-01

    Neuropeptide Y (NPY) can cause diuresis, natriuresis, and calciuresis in rats independently of the pressure-natriuresis mechanism (A. Bischoff and M. C. Michel. Pflügers Arch. 435: 443-453, 1998). Because this is seen in systemic but not intrarenal NPY infusion, we have investigated the possible mediator of tubular NPY effects in anesthetized rats. In the present study, infusion of NPY (2 micrograms . kg-1 . min-1) enhanced renovascular resistance by approximately 8 mmHg . ml-1 . min and enhanced urine and sodium excretion by approximately 450 microliter/15 min and approximately 60-85 micromol/15 min, respectively. Acute renal denervation did not alter renovascular or tubular NPY effects, indicating that a neuronally released mediator is not involved. Treatment with the angiotensin II-receptor antagonist losartan prevented the decline of the renovascular response with time but did not modify tubular NPY effects. The bradykinin B2-receptor antagonist icatibant accelerated the decline of the renovascular NPY effects with time; concomitantly, it attenuated NPY-induced diuresis and natriuresis and abolished NPY-induced calciuresis. The converting-enzyme inhibitor ramiprilat prevented the decline of the renovascular response with time; concomitantly, it magnified the NPY-induced diuresis, natriuresis, and calciuresis. We conclude that bradykinin may be involved in NPY-induced diuresis, natriuresis, and, in particular, calciuresis.

  13. Importance of Residual Water Permeability on the Excretion of Water during Water Diuresis in Rats

    PubMed Central

    Cheema-Dhadli, Surinder; Chong, Chee Keong; Kim, Namhee; Kamel, Kamel S

    2010-01-01

    When the concentration of sodium (Na+) in arterial plasma (PNa) declines sufficiently to inhibit the release of vasopressin, water will be excreted promptly when the vast majority of aquaporin 2 water channels (AQP2) have been removed from luminal membranes of late distal nephron segments. In this setting, the volume of filtrate delivered distally sets the upper limit on the magnitude of the water diuresis. Since there is an unknown volume of water reabsorbed in the late distal nephron, our objective was to provide a quantitative assessment of this parameter. Accordingly, rats were given a large oral water load, while minimizing non-osmotic stimuli for the release of vasopressin. The composition of plasma and urine were measured. The renal papilla was excised during the water diuresis to assess the osmotic driving force for water reabsorption in the inner medullary collecting duct. During water diuresis, the concentration of creatinine in the urine was 13-fold higher than in plasma, which implies that ~8% of filtered water was excreted. The papillary interstitial osmolality was 600 mOsm/L > the urine osmolality. Since 17% of filtered water is delivered to the earliest distal convoluted tubule micropuncture site, we conclude that half of the water delivered to the late distal nephron is reabsorbed downstream during water diuresis. The enormous osmotic driving force for the reabsorption of water in the inner medullary collecting duct may play a role in this reabsorption of water. Possible clinical implications are illustrated in the discussion of a case example. PMID:21468191

  14. Cardiac morphology and function in patients with and without residual diuresis on hemodialysis.

    PubMed

    Araujo, Salustiano; Lemes, Helton P; Cunha, Danny A; Queiroz, Vinicius S; Nascimento, Daniela D; Ferreira Filho, Sebastião Rodrigues

    2011-03-01

    In patients with chronic renal failure on hemodialysis, left ventricular hypertrophy is related to the increase in total peripheral vascular resistance and volume overload. The presence of residual diuresis enables greater control of the volemia of these. We evaluated the morpho-functional changes of the left ventricle in patients with chronic kidney disease on hemodyalisis treatment with and without residual diuresis. A total of 31 non diabetic patients were studied and they were divided into two groups: with residual diuresis (RD+) (n = 17) and without residual diuresis (RD-) (n = 14). In both groups, RD+ vs. RD-, using data from a Doppler echocardiogram differences were found, respectively, in the cardiac index (3.9 ± 0.2 vs. 3.0 ± 0.2 L/min/m²; p = 0.0056), systolic index (54 ± 2.9 vs. 45 ± 3.3 mL/b/m²; p = 0.04), end diastolic volume (141 ± 6.7 vs. 112 ± 7.6 mL; p = 0.008), end diastolic diameter (52 ± 0.7 vs. 48 ± 1.1 mm; p = 0.0072) and total peripheral resistance index (1121 ± 56 vs. 1529 ± 111 dyne.sec.cm-5; p = 0.001). RD+ had lower relative wall thickness than RD- (0.38 ± 0.01 vs. 0.45 ± 0.01; p = 0.0008). The ejection fraction and the left ventricular mass index were similar in both groups. The urinary 24-hour volume correlated with the relative wall thickness (r = -0.42; p = 0.0186) and with peripheral resistance index (r = -0.48; p = 0.0059). In conclusion, there were distinct ventricular geometric patterns and different functional performances between RD+ and RD- groups. The presence of residual diuresis can be responsible by these modifications in systolic function.

  15. Caffeine-induced diuresis and natriuresis is independent of renal tubular NHE3.

    PubMed

    Fenton, Robert A; Poulsen, Søren B; de la Mora Chavez, Samantha; Soleimani, Manoocher; Busslinger, Meinrad; Dominguez Rieg, Jessica A; Rieg, Timo

    2015-06-15

    Caffeine is one of the most widely consumed behavioral substances. We have previously shown that caffeine- and theophylline-induced inhibition of renal reabsorption causes diuresis and natriuresis, an effect that requires functional adenosine A1 receptors. In this study, we tested the hypothesis that blocking the Gi protein-coupled adenosine A1 receptor via the nonselective adenosine receptor antagonist caffeine changes Na(+)/H(+) exchanger isoform 3 (NHE3) localization and phosphorylation, resulting in diuresis and natriuresis. We generated tubulus-specific NHE3 knockout mice (Pax8-Cre), where NHE3 abundance in the S1, S2, and S3 segments of the proximal tubule was completely absent or severely reduced (>85%) in the thick ascending limb. Consumption of fluid and food, as well as glomerular filtration rate, were comparable in control or tubulus-specific NHE3 knockout mice under basal conditions, while urinary pH was significantly more alkaline without evidence for metabolic acidosis. Caffeine self-administration increased total fluid and food intake comparably between genotypes, without significant differences in consumption of caffeinated solution. Acute caffeine application via oral gavage elicited a diuresis and natriuresis that was comparable between control and tubulus-specific NHE3 knockout mice. The diuretic and natriuretic response was independent of changes in total NHE3 expression, phosphorylation of serine-552 and serine-605, or apical plasma membrane NHE3 localization. Although caffeine had no clear effect on localization of the basolateral Na(+)/bicarbonate cotransporter NBCe1, pretreatment with DIDS inhibited caffeine-induced diuresis and natriuresis. In summary, NHE3 is not required for caffeine-induced diuresis and natriuresis.

  16. Impact of water-induced diuresis on excretion profiles of ethanol, urinary creatinine, and urinary osmolality.

    PubMed

    Bendtsen, P; Jones, A W

    1999-01-01

    This article reports the impact of diuresis on urinary excretion of ethanol in seven healthy volunteers who drank 1000 mL of export beer (44 g ethanol) in 30 min and, 120 min later, ingested 500 or 1000 mL of water within 5 min. Urine was voided before drinking started and every 30-60 min for 360 min after the start of drinking. The concentration of ethanol in urine (UAC) was determined by headspace gas chromatography, the creatinine content was determined by Jaffe's method, and osmolality was measured by freezing point depression. Maximum diuresis coincided with the peak UAC and was reached 60-90 min after the end of drinking. The urinary creatinine and osmolality dropped appreciably after drinking beer, and the lowest values coincided with peak diuresis. Creatinine was < 0.2 g/L in 22% of urine specimens, and osmolality was < 200 mOsm/kg in 31% of specimens. Production of urine decreased as UAC entered the postabsorptive phase but increased again after the subjects drank water 120 min after alcohol consumption. The amount of ethanol recovered in urine was 681 mg (standard deviation [SD] 203 mg) corresponding to 1.5% (SD 0.46%) of the dose administered. The concentrations of ethanol in successive voids during the postabsorptive phase were not influenced after subjects drank 500 or 1000 mL of water although diuresis increased and urinary creatinine and osmolality decreased. Measuring UAC provides a reliable way to monitor recent drinking, and unlike the analysis of illicit drugs in urine, the concentrations of ethanol are not influenced by diuresis.

  17. Effects of bradykinin B2 receptor antagonism on the hypotensive effects of ACE inhibition.

    PubMed Central

    Bouaziz, H; Joulin, Y; Safar, M; Benetos, A

    1994-01-01

    1. The aim of this study was to determine the participation of endogenous bradykinin (BK) in the antihypertensive effects of the angiotensin converting enzyme inhibitor (ACEI), perindoprilat, in the spontaneously hypertensive rat (SHR) on different salt diets. 2. Conscious SHRs receiving either a low or a high NaCl diet were used in order to evaluate the respective roles of angiotensin II suppression and bradykinin stimulation in the acute hypotensive effects of perindoprilat. Two different B2 receptor antagonists (B 4146 and Hoe 140) were used after bolus administration of 7 mg kg-1 of the ACEI, perindoprilat. In separate animals, Hoe 140 was administered before the injection of perindoprilat. In other experiments, the effects of Hoe 140 on the hypotensive effects of the calcium antagonist, nicardipine, were tested. 3. The different NaCl diets had no effect on baseline blood pressure. Hoe 140 injection before ACE inhibition did not modify blood pressure. Perindoprilat caused more marked hypotension in the low salt-fed rats than in the high salt animals (P < 0.01). Administration of Hoe 140 or B4146 after perindoprilat significantly reduced the antihypertensive effects of perindoprilat in the different groups, but this effect was more pronounced in high salt-fed rats. However, in SHRs receiving Hoe 140 before perindoprilat, the antihypertensive effect of perindoprilat was completely abolished in both high or low salt diet rats. In separate experiments we confirmed that Hoe 140 did not affect the hypotensive efficacy of the calcium antagonist, nicardipine. 4. Our study shows that inhibition of endogenous bradykinin degradation participates in the acute antihypertensive effects of perindoprilat in SHRs. The role of bradykinin is more pronounced following exposure to a high salt diet i.e., when the renin-angiotensin system is suppressed.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7858859

  18. Discovery of novel selective hypotensive vasopressin peptides that exhibit little or no functional interactions with known oxytocin/vasopressin receptors

    PubMed Central

    Chan, W Y; Wo, N C; Stoev, S; Cheng, L L; Manning, M

    1998-01-01

    Arginine-vasopressin (VP) has both vasoconstricting and vasodilating action. We report here the discovery of four novel selective hypotensive VP analogues: d(CH2)5[D-Tyr(Et)2,Arg3,Val4]AVP; d(CH2)5[D-Tyr(Et)2,Lys3,Val4]AVP and their iodinatable Tyr-NH29 analogues.Bioassays in rats for activities characteristic of neurohypophysial peptides showed that the four VP peptides possessed little or no V1a, V2 or oxytocin (OT) receptor agonistic or antagonistic activities.In anaesthetized rats, these peptides (0.05–0.10 mg kg−1 i.v.) elicited a marked fall in arterial blood pressure.Blockade of cholinoceptors, adrenoceptors and bradykinin B2 receptors, and inhibition of prostaglandin synthesis had little effect on their vasodepressor action.Classical V1a, V2 and OT receptor antagonists did not block the vasodepressor response.L-NAME, 0.2 mg kg−1 min−1, markedly suppressed the hypotensive response to ACh but not the vasodepressor response to the hypotensive VP peptides. However, the duration of the vasodepressor response was shortened. Very high doses of L-NAME attenuated both the vasodepressor response and the duration of action.These findings indicate that the vasodepressor action of these VP peptides is independent of the peripheral autonomic, bradykinin and PG systems and is not mediated by the known classical OT/VP receptors. NO does not appear to have an important role in their vasodepressor action.The discovery of these novel VP peptides could lead to the development of new tools for the investigation of the complex cardiovascular actions of VP and the introduction of a new class of hypotensive agents. The two iodinatable hypotensive VP peptides could be radiolabelled as potential markers for the localization of the receptor system involved. PMID:9831918

  19. Effects of in vivo 'priming' on endotoxin-induced hypotension and tissue injury. The role of PAF and tumor necrosis factor.

    PubMed Central

    Sun, X. M.; Hsueh, W.; Torre-Amione, G.

    1990-01-01

    Exogenously administered tumor necrosis factor-alpha (TNF) and bacterial endotoxin (LPS) induce shock and tissue injury. Here, the authors studied the effect of endogenous TNF on LPS-induced hypotension and tissue injury and investigated the role of PAF in these responses. Rats were primed with intraperitoneal injection of zymosan 24 hours before, or Bacillus Calmette-Guérin (BCG) 12 to 15 days before intravenous injection of low dose (0.5 mg/kg) LPS. It was found that nonprimed animals showed mild hypotension and moderate leukopenia in response to LPS. In contrast, zymosanprimed rats developed shock and marked leukopenia, and more severe bowel injury than nonprimed rats. The authors then showed that, following LPS injection, zymosan-primed animals had higher TNF and platelet-activating factor (PAF) levels than nonprimed rats. Pretreatment of the animal with PAF antagonist, SRI 63-441, markedly ameliorated the hypotension and tissue injury. Interestingly, BCG-primed rats did not show aggravation of LPS-induced hypotension. Only TNF (but not PAF) level in these animals was increased. Thus, it appears that TNF release alone, without a sufficient increase in PAF, is incapable of causing severe hypotension. However, most of the BCG-primed animals showed tissue injury, which could be prevented by pretreatment with PAF antagonist. The authors discuss the possible mechanisms of this discrepancy between systemic and local responses in BCG-primed animals. Images Figure 3 PMID:2327475

  20. Bed Rest and Orthostatic-Hypotensive Intolerance

    NASA Technical Reports Server (NTRS)

    Schneider, Suzanne M.

    2000-01-01

    Orthostatic tolerance may be defined as the ability of humans to maintain cerebral perfusion and consciousness upon movement from a supine or sitting position to the upright posture; for example, subjects can stand suddenly or be tilted to the head-up body position. Similar but not identical physiological responses can be induced by positive G(sub Z) (head to foot) acceleration or exposure to lower body negative pressure (LBNP). The objective is to suddenly shift blood to the lower body to determine how effectively cardiovascular and neural-hormonal compensatory responses react to maintain blood pressure. In the most precise method for measuring tolerance, individuals would be stressed until they faint (syncope). However, the potential consequences and discomforts of such a test usually prohibit such a procedure so that few investigators actually induce syncope. In a more common approach, subjects are exposed to a given level of stress, for example, head-up tilt for 15 min, and any increases in heart rate or decreases in blood pressure are interpreted as indicators of progress toward syncope. Presumably, the greater the perturbation of heart rate and blood pressure, the closer to "tolerance," i.e., point of unconsciousness. Another more appropriate approach is to induce a progressively increasing hypotensive stress until pre-determined physiological responses or pre-syncopal symptoms appear. The physiological criteria may include a sudden drop in systolic blood pressure (greater than 25 mm/min), a sudden drop in heart rate (greater than 15 beats/min), or a systolic blood pressure less than 70 mmHg. The most common pre-syncopal symptoms include lightheadedness, stomach awareness or distress, feelings of warmth, tingly skin, and light to profuse sweating. Usually a combination of physiological responses and symptoms occurs such that, on different days, the tolerance time to the same orthostatic protocol is reproducible for a given individual. The assumption is that

  1. Genetic AVP deficiency abolishes cold-induced diuresis but does not attenuate cold-induced hypertension.

    PubMed

    Sun, Zhongjie

    2006-06-01

    Chronic cold exposure causes hypertension and diuresis. The aim of this study was to determine whether vasopressin (AVP) plays a role in cold-induced hypertension and diuresis. Two groups of Long-Evans (LE) and two groups of homozygous AVP-deficient Brattleboro (VD) rats were used. Blood pressure (BP) was not different among the four groups during a 2-wk control period at room temperature (25 degrees C, warm). After the control period, one LE group and one VD group were exposed to cold (5 degrees C); the remaining groups were kept at room temperature. BP and body weight were measured weekly during exposure to cold. Food intake, water intake, urine output, and urine osmolality were measured during weeks 1, 3, and 5 of cold exposure. At the end of week 5, all animals were killed and blood was collected for measurement of plasma AVP. Kidneys were removed for measurement of renal medulla V2 receptor mRNA and aquaporin-2 (AQP-2) protein expression. BP of LE and VD rats increased significantly by week 2 of cold exposure and reached a high level by week 5. BP elevations developed at approximately the same rate and to the same degree in LE and VD rats. AVP deficiency significantly increased urine output and solute-free water clearance and decreased urine osmolality. Chronic cold exposure increased urine output and solute-free water clearance and decreased urine osmolality in LE rats, indicating that cold exposure caused diuresis in LE rats. Cold exposure failed to affect these parameters in VD rats, suggesting that the AVP system is responsible for cold-induced diuresis. Cold exposure did not alter plasma AVP in LE rats. Renal medulla V2 receptor mRNA and AQP-2 protein expression levels were decreased significantly in the cold-exposed LE rats, suggesting that cold exposure inhibited renal V2 receptors and AVP-inducible AQP-2 water channels. We conclude that 1) AVP may not be involved in the pathogenesis of cold-induced hypertension, 2) the AVP system plays a critical role

  2. Cardiovascular effects of thyrotropin-releasing hormone in normotensive and hypotensive rats: role of rostral ventrolateral medulla.

    PubMed

    Yan, J; Chen, H; Liao, W; Lu, S

    1992-07-01

    To ascertain the central mechanism of the effects of thyrotropin-releasing hormone (TRH) on the cardiovascular system, we evaluated the effects of this neuropeptide on unit fires in the rostral ventro-lateral medulla (RVL), mean arterial pressure (MAP), and heart rate (HR) in normotensive and hypotensive rats. Intracerebroventricular injection (i.c.v.) of 10 micrograms TRH significantly increased MAP and HR in both normotensive and hypotensive rats. No similar effects were observed after saline injection. If electrolytic lesions of bilateral RVL were made, the cardiovascular effects of TRH i.c.v. failed to occur. TRH i.c.v. markedly increased the firing frequency of most units in the RVL. In particular, TRH i.c.v. increased the firing frequency of most units excitatory to a fall in MAP and decreased the firing frequency of most units inhibitory to a fall in MAP in normotensive rats. Moreover, a drop of MAP as low as 40 mmHg for 10 min resulted in an increase of the firing frequency of most units. The effect of TRH i.c.v. on the RVL units in the hypotensive rats was similar to that in the normotensive rats. Our findings suggest that TRH is able to intensify the cardiovascular activities and the RVL plays a key role in the effects of TRH on the cardiovascular system in both normotensive and hypotensive rats.

  3. What Are the Signs and Symptoms of Hypotension?

    MedlinePlus

    ... away after sitting down. Severe Hypotension Linked to Shock In shock , not enough blood and oxygen flow to the ... sleepiness, and confusion. In the earliest stages of shock, it may be hard to detect any signs ...

  4. Spontaneous Intracranial Hypotension Secondary to Lumbar Disc Herniation

    PubMed Central

    Kim, Kyoung-Tae

    2010-01-01

    Spontaneous intracranial hypotension is often idiopathic. We report on a patient presenting with symptomatic intracranial hypotension and pain radiating to the right leg caused by a transdural lumbar disc herniation. Magnetic resonance (MR) imaging of the brain revealed classic signs of intracranial hypotension, and an additional spinal MR confirmed a lumbar transdural herniated disc as the cause. The patient was treated with a partial hemilaminectomy and discectomy. We were able to find the source of cerebrospinal fluid leak, and packed it with epidural glue and gelfoam. Postoperatively, the patient's headache and log radiating pain resolved and there was no neurological deficit. Thus, in this case, lumbar disc herniation may have been a cause of spontaneous intracranial hypotension. PMID:20157378

  5. Clinical implications of delayed orthostatic hypotension

    PubMed Central

    Freeman, Roy

    2015-01-01

    Objective: To define the long-term outcome of delayed orthostatic hypotension (OH). Hypothesis: Delayed OH is an early and milder form of OH that progresses over time. Methods: We reviewed the medical records of 230 previously reported patients who completed autonomic testing at our center from January 1, 2002, through December 31, 2003. All available information on clinical diagnosis, mortality, medication use, and autonomic testing were extracted and included in the reported outcomes. Standard criteria were used to define OH and delayed OH. Results: Forty-eight individuals with delayed OH, 42 individuals with OH, and 75 controls had complete follow-up data. Fifty-four percent of individuals with delayed OH progressed to OH. Thirty-one percent of individuals with delayed OH developed an α-synucleinopathy. The 10-year mortality rate in individuals with delayed OH was 29%, in individuals with baseline OH was 64%, and in controls was 9%. The 10-year mortality of individuals who progressed to OH was 50%. Progression to OH was associated with developing an α-synucleinopathy, baseline diabetes, and abnormal baseline autonomic test results. Conclusion: Delayed OH frequently progresses to OH with a high associated mortality. PMID:26400576

  6. Cognitive performance in hypotensive persons with spinal cord injury

    PubMed Central

    Jegede, Adejoke B.; Rosado-Rivera, Dwindally; Bauman, William A.; Cardozo, Christopher P.; Sano, Mary; Moyer, Jeremy M.; Brooks, Monifa; Wecht, Jill Maria

    2010-01-01

    Background Due to sympathetic de-centralization, individuals with spinal cord injury (SCI), especially those with tetraplegia, often present with hypotension, worsened with upright posture. Several investigations in the non-SCI population have noted a relationship between chronic hypotension and deficits in memory, attention and processing speed and delayed reaction times. Objective To determine cognitive function in persons with SCI who were normotensive or hypotensive over a 24-h observation period while maintaining their routine activities. Methods Subjects included 20 individuals with chronic SCI (2–39 years), 13 with tetraplegia (C4–8) and 7 with paraplegia (T2–11). Individuals with hypotension were defined as having a mean 24-h systolic blood pressure (SBP) below 110 mmHg for males and 100 mmHg for females, and having spent ≥50% of the total time below these gender-specific thresholds. The cognitive battery used included assessment of memory (CVLT), attention and processing speed (Digit Span, Stroop word and color and Oral Trails A), language (COWAT) and executive function (Oral Trails B and Stroop color–word). Results Demographic parameters did not differ among the hypotensive and normotensive groups; the proportion of individuals with tetraplegia (82%) was higher in the hypotensive group. Memory was significantly impaired (P<0.05) and there was a trend toward slowed attention and processing speed (P<0.06) in the hypotensive compared to the normotensive group. Interpretation These preliminary data suggest that chronic hypotension in persons with SCI is associated with deficits in memory and possibly attention and processing speed, as previously reported in the non-SCI population. PMID:19842013

  7. Orthostatic hypotension as a manifestation of vitamin B12 deficiency.

    PubMed

    Ganjehei, Leila; Massumi, Ali; Razavi, Mehdi; Wilson, James M

    2012-01-01

    A 90-year-old woman with orthostatic hypotension and near-syncope was found to have a low-normal level of vitamin B(12) and no other medical findings that could explain her orthostasis. Her symptoms responded to vitamin B(12) replacement therapy. This case shows that vitamin B(12) deficiency can induce orthostatic hypotension and syncope that are correctable by vitamin B(12) replacement.

  8. Risk Factors for Hypotension in Urgently Intubated Burn Patients

    DTIC Science & Technology

    2012-01-01

    fold increase in the odds of death. The use of propofol for the induction of anesthesia for endotracheal intubation in critically ill burned patients...did not increase the odds of hypotension or death. In burn patients requiring emergent endotracheal intubation in the BICU, the care team should...01 DEC 2012 2. REPORT TYPE N/A 3. DATES COVERED - 4. TITLE AND SUBTITLE Risk factors for hypotension in urgently intubated burn patients 5a

  9. Forced diuresis with the RenalGuard system: impact on contrast induced acute kidney injury.

    PubMed

    Solomon, Richard

    2014-01-01

    Kidney injury following the administration of iodinated contrast media occurs particularly in patients with reduced kidney and cardiac function and when large doses of contrast are used. There is little compelling evidence that vasodilators and anti-oxidants prevent this injury. Most prevention trials have employed intravenous volume loading as a central strategy. However, the success of this approach depends upon maintaining euvolemia while producing a vigorous diuresis. A novel strategy for maintaining euvolemia and inducing a vigorous diuresis has been developed using the RenalGuard system. In this review; the mechanism of protective action is reviewed. The trials of the RenalGuard device are reviewed and future uses of the device are discussed.

  10. Evaluation of Polyuria: The Roles of Solute Loading and Water Diuresis.

    PubMed

    Bhasin, Bhavna; Velez, Juan Carlos Q

    2016-03-01

    Polyuria, defined as daily urine output in excess of 3.0 to 3.5L/d, can occur due to solute or water diuresis. Solute-induced polyuria can be seen in hospitalized patients after a high solute load from exogenous protein administration or following relief of urinary obstruction. Similar clinical scenarios are rarely encountered in the outpatient setting. We describe a case of polyuria due to high solute ingestion and excessive water intake leading to a mixed picture of solute and water diuresis. Restriction of the daily solute load and water intake resulted in complete resolution of polyuria. Determination of the daily excreted urinary osmoles may yield important clues to the cause of polyuria and should be included in the routine workup of polyuria.

  11. Osmotic diuresis-induced hypernatremia: better explained by solute-free water clearance or electrolyte-free water clearance?

    PubMed

    Popli, Subhash; Tzamaloukas, Antonios H; Ing, Todd S

    2014-01-01

    Hypernatremia may result from inadequate water intake, excessive water loss or a combination of the two. Osmotic diuresis leads to losses of both solute and water. The relationship between solute and water losses determines the resulting changes in serum osmolality and sodium concentration. Total solute loss is routinely higher than loss of water in osmotic diuresis. Theoretically, then, decreases in serum osmolality (and serum sodium concentration) should follow. In clinical situations of osmotic diuresis, however, reduction in osmolality can take place, but not reduction in serum sodium concentration. It is of note that serum sodium concentration changes are related to urinary losses of sodium and potassium but not to the loss of total solute. In osmotic diuresis, the combined loss of sodium and potassium per liter of urine is lower than the concurrent serum sodium level. Consequently, hypernatremia can ensue. A patient who presented with osmotic diuresis and hypernatremia is described here. In this patient, we have shown that electrolyte-free water clearance is a better index of the effect of osmotic diuresis on serum sodium concentration than the classic solute-free water clearance.

  12. Venlafaxine-Induced Orthostatic Hypotension in a Geriatric Patient

    PubMed Central

    Chikkaramanjegowda, Vidyashree; de Leon, Jose

    2013-01-01

    Venlafaxine is not usually associated with risk of orthostatic hypotension. A 65-year-old US Caucasian female taking 225 mg/day of venlafaxine extended-release developed symptomatic orthostatic hypotension. The systolic and diastolic blood pressure dropped by 25 and 18 mm Hg, respectively, from supine position to standing position within 3 minutes. The patient was otherwise healthy and the orthostatic hypotension resolved with venlafaxine discontinuation. This was a probable venlafaxine adverse drug reaction according to the Naranjo scale. This case contributes to the scarce literature that indicates that clinicians need to be aware that occasionally venlafaxine can induce clinically significant orthostatic hypotension, particularly in geriatric patients. Our patient did not have orthostatic hypotension when she was taking venlafaxine at 60 years of age in higher venlafaxine doses (300 mg/day) but developed this adverse drug reaction when venlafaxine was restarted at the geriatric age. This case indicates that a history of prior tolerance to venlafaxine does not guarantee tolerance after 65 years of age. If a clinician decides to use venlafaxine in geriatric patients, the clinician should warn the patient about the risk of orthostatic hypotension and consider very slow titration and low doses. PMID:23984153

  13. Antagonistic effects of atipamezole and yohimbine on xylazine-induced diuresis in healthy dogs.

    PubMed

    Talukder, Hasanuzzaman; Hikasa, Yoshiaki; Matsuu, Aya; Kawamura, Hiroe

    2009-05-01

    The aim of this study was to investigate and compare the antagonistic effects of atipamezole and yohimbine on xylazine-induced diuresis in healthy dogs. Five healthy male beagles were assigned to each of the 8 treatment groups in a randomized design at 1-week intervals in the same dog. One group was not medicated. The dogs in the other groups received 2 mg/kg xylazine intramuscularly (IM) and a treatment of saline (control), 50, 100 or 300 microg/kg of each atipamezole or yohimbine IM 0.5 hr later. Urine and blood samples were collected 11 times over the course of 24 hr. Urine volume, pH, specific gravity and creatinine values; osmolality, electrolyte and arginine vasopressin (AVP) values in both urine and plasma; and plasma atrial natriuretic peptide (ANP) concentration were measured. Both atipamezole and yohimbine antagonized xylazine-induced diuresis. The reversal effect of yohimbine was more potent, but not dose-dependent at the tested doses, in contrast with atipamezole. Both atipamezole and yohimbine exhibited similar potency in reversing the decreases in urine specific gravity, osmolality, creatinine, sodium and chloride concentrations and the increase in the plasma potassium concentration induced by xylazine. Both also inhibited xylazine-induced diuresis without significantly altering the hormonal profile in the dogs. A higher dose of atipamezole tended to increase the plasma ANP concentration. This may not be due only to actions mediated by alpha(2)-adrenoceptors. Both drugs can be used as antagonistic agents against xylazine-induced diuresis in healthy dogs.

  14. Effect of water temperature on diuresis-natriuresis: AVP, ANP, and urodilatin during immersion in men

    NASA Technical Reports Server (NTRS)

    Nakamitsu, S.; Sagawa, S.; Miki, K.; Wada, F.; Nagaya, K.; Keil, L. C.; Drummer, C.; Gerzer, R.; Greenleaf, J. E.; Hong, S. K.

    1994-01-01

    Effects of water temperature on diuresis, natriuresis, and associated endocrine responses during head-out immersion were studied in eight men during four 5-h experimental conditions: air control at 28 C and immersion at 34.5 C (thermoneutral (Tnt)), 36 C (above Tnt (aTnt)), and 32 C (below Tnt (bTnt). Esophageal temperature decreased by approximately 0.4 C in bTnt and increased by approximately 0.5 C in aTnt. Cardiac output increased by approximately 80% in aTnt and approximately 40% in bTnt while thoracic impedance, an index of central blood pooling, decreased by 7.5 ohms in bTnt (NS vs. Tnt) and 8.8 ohms in aTnt. Total peripheral resistance decreased at all temperatures (50% in aTnt, 20% in bTnt). Urine flow and Na(+) excretion increased by sixfold in bTnt and Tnt but by only threefold in aTnt. Creatinine clearance was unchanged while osmolal clearance (but not free water clearance) increased two-fold with all immersions. Plasma atrial natriuretic peptide (ANP), urinary urodilatin, and urinary guanosine 3',5'-cyclic monophosphate increased while plasma renin activity, aldosterone, and arginine vasopressin (AVP) decreased similarly at all temperatures. bTnt did not potentiate diuresis by selective attenuation of AVP. The overall natriuretic response exhibited a higher correlation with urodilatin than with ANP. Because diuresis and natriuresis were significantly attenuated in aTnt where central blood pooling was greater, we conclude that mechanisms other than the atrial stretch receptor reflex, i.e., urodilatin and effective arterial blood volume, may play more predominant roles in the mechanism of immersion-induced diuresis and natriuresis.

  15. Thienoquinolins exert diuresis by strongly inhibiting UT-A urea transporters.

    PubMed

    Ren, Huiwen; Wang, Yanhua; Xing, Yongning; Ran, Jianhua; Liu, Ming; Lei, Tianluo; Zhou, Hong; Li, Runtao; Sands, Jeff M; Yang, Baoxue

    2014-12-15

    Urea transporters (UT) play an important role in the urine concentration mechanism by mediating intrarenal urea recycling, suggesting that UT inhibitors could have therapeutic use as a novel class of diuretic. Recently, we found a thienoquinolin UT inhibitor, PU-14, that exhibited diuretic activity. The purpose of this study was to identify more potent UT inhibitors that strongly inhibit UT-A isoforms in the inner medullary collecting duct (IMCD). Efficient thienoquinolin UT inhibitors were identified by structure-activity relationship analysis. Urea transport inhibition activity was assayed in perfused rat terminal IMCDs. Diuretic activity of the compound was determined in rats and mice using metabolic cages. The results show that the compound PU-48 exhibited potent UT-A inhibition activity. The inhibition was 69.5% with an IC50 of 0.32 μM. PU-48 significantly inhibited urea transport in perfused rat terminal IMCDs. PU-48 caused significant diuresis in UT-B null mice, which indicates that UT-A is the target of PU-48. The diuresis caused by PU-48 did not change blood Na(+), K(+), or Cl(-) levels or nonurea solute excretion in rats and mice. No toxicity was detected in cells or animals treated with PU-48. The results indicate that thienoquinolin UT inhibitors induce a diuresis by inhibiting UT-A in the IMCD. This suggests that they may have the potential to be developed as a novel class of diuretics with fewer side effects than classical diuretics.

  16. Diuresis by intravenous administration of xanthurenic acid in rats, and inhibition by probenecid.

    PubMed

    Uwai, Yuichi; Nakashima, Yuta; Honjo, Emi; Kawasaki, Tatsuya; Nabekura, Tomohiro

    2014-01-01

    The conjugates with sulfate and glucoside of xanthurenic acid, a tryptophan metabolite, were reported to show natriuresis. Sulfotransferase for xanthurenic acid works in the renal proximal tubule to produce the sulfate of xanthurenic acid as well as the liver, and we recently found that xanthurenic acid is a substrate of renal organic anion transporter OAT1. The purpose of this study was to examine relationship between the transport by OAT1 and diuresis related with xanthurenic acid. Drug transport experiment using Xenopus laevis oocytes represented that probenecid inhibited xanthurenic acid uptake by rat OAT1 (rOAT1). Although no diuresis was recognized by the intravenous injection of xanthurenic acid as a bolus in rats, the addition of its infusion exhibited natriuresis. Simultaneous administration of probenecid significantly decreased the urine volume and excreted amounts of sodium into urine. These findings showed the diuresis by the xanthurenic acid administration, and it was probenecid-sensitive. The rOAT1-mediated transport of xanthurenic acid might, at least in part, contribute to its diuretic effect.

  17. Antagonistic effects of atipamezole, yohimbine and prazosin on medetomidine-induced diuresis in healthy cats.

    PubMed

    Murahata, Yusuke; Yamamoto, Asami; Miki, Yuya; Hikasa, Yoshiaki

    2014-03-01

    This study aimed to investigate and compare the antagonistic effects of atipamezole, yohimbine and prazosin on medetomidine-induced diuresis in healthy cats. Five cats were repeatedly used in each of the 9 groups. One group was not medicated. Cats in the other groups received 40 µg/kg medetomidine intramuscularly and saline (as the control), 160 µg/kg prazosin, or 40, 160 or 480 µg/kg atipamezole or yohimbine intravenously 0.5 hr later. Volume, pH and specific gravity of urine; plasma arginine vasopressin (AVP) level; and creatinine, osmolality and electrolyte levels in both urine and plasma were measured. Both atipamezole and yohimbine, but not prazosin, antagonized medetomidine-induced diuresis. The antidiuretic effect of atipamezole was more potent than that of yohimbine, but was not dose dependent, in contrast to the effect of yohimbine at the tested doses. Both atipamezole and yohimbine reversed medetomidine-induced decreases in both urine specific gravity and osmolality and increases in plasma osmolality and free-water clearance. Antidiuresis of either atipamezole or yohimbine was not related to the area under the curve for AVP level, although the highest dose of both atipamezole and yohimbine initially and temporarily increased plasma AVP levels, suggesting that this may partly influence the antidiuretic effects of both agents. The diuretic effect of medetomidine in cats may be mediated by α2-adrenoceptors, but not α1-adrenoceptors. Atipamezole and yohimbine can be used as antagonistic agents against medetomidine-induced diuresis in healthy cats.

  18. Effect of canagliflozin on blood pressure and adverse events related to osmotic diuresis and reduced intravascular volume in patients with type 2 diabetes mellitus.

    PubMed

    Weir, Matthew R; Januszewicz, Andrzej; Gilbert, Richard E; Vijapurkar, Ujjwala; Kline, Irina; Fung, Albert; Meininger, Gary

    2014-12-01

    ] and polyuria [increased urine frequency]) vs placebo (6.7%, 5.6%, and 0.8%). The incidence of intravascular volume reduction-related AEs (eg, orthostatic hypotension and postural dizziness) was low across groups (1.2%, 1.3%, and 1.1%). In summary, canagliflozin was associated with reduced BP in patients with T2DM across a range of baseline BPs, with increased incidence of AEs related to osmotic diuresis but not intravascular volume reduction.

  19. Induced hypotension during anesthesia with special reference to orthognathic surgery.

    PubMed Central

    Rodrigo, C.

    1995-01-01

    Since Gardner first used arteriotomy during anesthesia to improve visibility in the surgical field, various techniques and pharmacological agents have been tried for the same purpose. With reports documenting the spread of acquired immune deficiency syndrome through blood transfusions, prevention of homologous blood transfusions during surgery has also become a major concern. Induced hypotension has been used to reduce blood loss and thereby address both issues. In orthognathic surgery, induced hypotension during anesthesia has been used for similar reasons. It is recommended that hypotensive anesthesia be adjusted in relation to the patient's preoperative blood pressure rather than to a specific target pressure and be limited to that level necessary to reduce bleeding in the surgical field and in duration to that part of the surgical procedure deemed to benefit by it. A mean arterial blood pressure (MAP) 30% below a patient's usual MAP, with a minimum MAP of 50 mm Hg in ASA Class I patients and a MAP not less than 80 mm Hg in the elderly, is suggested to be clinically acceptable. Various pharmacological agents have been used for induced hypotension during orthognathic surgery. In addition, there are many drugs that have been used in other types of surgery that could be used in orthognathic surgery to induce hypotension. Recent reports using control groups do not show significant differences in morbidity and mortality attributable to induced hypotension during anesthesia. Appropriate patient evaluation and selection, proper positioning and monitoring, and adequate fluid therapy are stressed as important considerations in patients undergoing induced hypotension during orthognathic surgery. PMID:8934953

  20. [Prevention and treatment of hypotension during Caesarean delivery].

    PubMed

    Erler, Ines; Gogarten, Wiebke

    2007-03-01

    Regional anesthesia for Caesarean delivery is often accompanied by a reduction in maternal blood pressure. Maternal hypotension may lead to a reduction in uteroplacental blood flow with consecutive fetal acidosis. In order to avoid reductions in uteroplacental blood flow, tremendous research has been performed, showing that the avoidance of aortocaval compression, compression of the lower extremities, and prehydration with colloids are effective in reducing maternal hypotension. Further means include the recent introduction of low dose spinal anesthesia with a combination of small amounts of local anesthetics and opioids. Nevertheless, maternal hypotension is not always preventable and the use of vasopressors is still frequently required. Although ephedrine has been considered the vasopressor of choice over the last decades, current studies show that fetal acidosis is less frequently encountered with the use of phenylephrine, which should thus be considered as a first-line agent.

  1. Spontaneous intracranial hypotension syndrome: contribution of radioisotope cisternography.

    PubMed

    Suárez, J P; Domínguez, M L; Gómez, M A; Muñoz, J L

    Spontaneous intracranial hypotension is a clinical syndrome caused by a loss of cerebrospinal fluid volume, usually secondary to leaking through structural defects of the spinal dura mater. Radioisotope cisternography (RC) can confirm the diagnosis of spontaneous intracranial hypotension, especially in doubtful or atypical case presentations. A retrospective study was conducted on 8 patients who underwent RC because spontaneous intracranial hypotension was suspected, and they presented with atypical clinical manifestations and/or inconclusive findings in other imaging techniques. RC detected paradural extravasation of cerebrospinal fluid in 7 patients. Moreover, there was indirect evidence of cerebrospinal fluid leaks in all 8 patients (early appearance of radioactivity in the bladder, soft tissue uptake of radioisotope and/or reduction in the amount of radiotracer in the brain at 24hours). RC had a significant impact on the diagnosis of 6 patients, and on the therapeutic management of 4 patients.

  2. Refractory hypotension in a patient with Wernicke's encephalopathy.

    PubMed

    Wang, Shi; Hou, Xiaojun; Ding, Suju; Guan, Yangtai; Zhen, Huimin; Tu, Laihui; Qiu, Yiqing

    2012-01-01

    A 57-year-old male patient with gastric carcinoma underwent radical distal gastrectomy type II + Braun anastomosis, and received total parenteral nutrition for 10 days after surgery, followed by small amounts of semi-liquid nutrition for 3 days and liquid nutrition for 2 days. The patient developed refractory hypotension for more than 1 week in the early course of disease, and on Day 15 after surgery presented with characteristic signs of Wernicke's encephalopathy, including diplopia and mental confusion. The hypotension did not improve despite appropriate fluid replacement soon after admission. Treatment with moderate dose of thiamine for 3 months partly relieved ophthalmoplegia and confusion, but not Korsakoff syndrome. This extraordinary presentation with refractory hypotension and the unusual course of the disease encouraged us to present this case.

  3. Orthostatic hypotension in patients, bed rest subjects, and astronauts

    NASA Technical Reports Server (NTRS)

    Lathers, C. M.; Charles, J. B.

    1994-01-01

    Orthostatic hypotension after even short space flights has affected a significant number of astronauts. Given the need for astronauts to function at a high level of efficiency during and after their return from space, the application of pharmacologic and other treatments is strongly indicated. This report addresses the clinical problem of orthostatic hypotension and its treatments to ascertain whether pharmacologic or physiologic treatment may be useful in the prevention of orthostatic hypotension associated with space flight. Treatment of orthostatic hypotension in patients now includes increasing intravascular volume with high sodium intake and mineralocorticoids, or increasing vascular resistance through the use of drugs to stimulate alpha or block beta vascular receptors. Earlier treatment used oral sympathomimetic ephedrine hydrochloride alone or with "head-up" bed rest. Then long-acting adrenocortical steroid desoxycorticosterone preparations with high-salt diets were used to expand volume. Fludrocortisone was shown to prevent the orthostatic drop in blood pressure. The combination of the sympathomimetic amine hydroxyamphetamine and a monoamine oxidase inhibitor tranylcypromine has been used, as has indomethacin alone. Davies et al. used mineralocorticoids at low doses concomitantly with alpha-agonists to increase vasoconstrictor action. Schirger et al used tranylcypromine and methylphenidate with or without a Jobst elastic leotard garment or the alpha-adrenergic agonist midodrine (which stimulates both arterial and venous systems without direct central nervous system or cardiac effects). Vernikos et al established that the combination of fludrocortisone, dextroamphetamine, and atropine exhibited a beneficial effect on orthostatic hypotension induced by 7-day 6 degrees head-down bed rest (a model used to simulate the weightlessness of space flight). Thus, there are numerous drugs that, in combination with mechanical techniques, including lower body negative

  4. Midodrine as a Countermeasure for Post-Spaceflight Orthostatic Hypotension

    NASA Technical Reports Server (NTRS)

    Stenger, Michael B.; Stein, Sydney P.; Meck, Janice V.; Platts, Steven H.

    2008-01-01

    One possible mechanism for post-spaceflight orthostatic hypotension, which affects approximately 30% of astronauts after short duration shuttle missions, is inadequate norepinephrine release during upright posture. We performed a two phased study to determine the effectiveness of an alpha1-adrenergic agonist, midodrine, as a countermeasure to post-spaceflight orthostatic hypotension. The first phase of the study examined the landing day orthostatic responses of six veteran astronauts after oral midodrine (10 mg) administered on the ground within approximately two hours of wheel stop. One female crewmember exhibited orthostatic hypotension in a previous flight but not after midodrine. Five male crewmembers, who did not exhibit orthostatic hypotension during previous flights, also did not show signs of orthostatic hypotension after midodrine. Additionally, phase one showed that midodrine did not cause hypertension in these crewmembers. In the second phase of this study, midodrine is ingested inflight (near time of ignition, TIG) and orthostatic responses are determined immediately upon landing via an 80 degree head-up tilt test performed on the crew transport vehicle (CTV). Four of ten crewmembers have completed phase two of this study. Two crewmembers completed the landing day tilt tests, while two tests were ended early due to presyncopal symptoms. All subjects had decreased landing day stroke volumes and increased heart rates compared to preflight. Midodrine appears to have increased total peripheral resistance in one crewmember who was able to complete the landing day tilt test. The effectiveness of midodrine as a countermeasure to immediate post-spaceflight orthostatic hypotension has yet to be determined; interpretation is made more difficult due to low subject number and the lack of control subjects on the CTV.

  5. Antagonistic effects of atipamezole, yohimbine, and prazosin on xylazine-induced diuresis in clinically normal cats

    PubMed Central

    Murahata, Yusuke; Miki, Yuya; Hikasa, Yoshiaki

    2014-01-01

    This study aimed to investigate and compare the antagonistic effects of atipamezole, yohimbine, and prazosin on xylazine-induced diuresis in clinically normal cats. Five cats were repeatedly used in each of the 9 groups. One group was not medicated. Cats in the other groups received 2 mg/kg BW xylazine intramuscularly, and saline (as the control); 160 μg/kg BW prazosin; or 40, 160, or 480 μg/kg BW atipamezole or yohimbine intravenously 0.5 h later. Urine and blood samples were collected 10 times over 8 h. Urine volume, pH, and specific gravity; plasma arginine vasopressin (AVP) concentration; and creatinine, osmolality, and electrolyte values in both urine and plasma were measured. Both atipamezole and yohimbine antagonized xylazine-induced diuresis, but prazosin did not. The antidiuretic effect of atipamezole was more potent than that of yohimbine but not dose-dependent, in contrast to the effect of yohimbine at the tested doses. Both atipamezole and yohimbine reversed xylazine-induced decreases in both urine specific gravity and osmolality, and the increase in free water clearance. Glomerular filtration rate, osmolar clearance, and plasma electrolyte concentrations were not significantly altered. Antidiuresis of either atipamezole or yohimbine was not related to the area under the curve for AVP concentration, although the highest dose of both atipamezole and yohimbine increased plasma AVP concentration initially and temporarily, suggesting that this may in part influence antidiuretic effects of both agents. The diuretic effect of xylazine in cats may be mediated by α2-adrenoceptors but not α1-adrenoceptors. Atipamezole and yohimbine can be used as antagonistic agents against xylazine-induced diuresis in clinically normal cats. PMID:25356000

  6. Antagonistic effects of atipamezole, yohimbine, and prazosin on xylazine-induced diuresis in clinically normal cats.

    PubMed

    Murahata, Yusuke; Miki, Yuya; Hikasa, Yoshiaki

    2014-10-01

    This study aimed to investigate and compare the antagonistic effects of atipamezole, yohimbine, and prazosin on xylazine-induced diuresis in clinically normal cats. Five cats were repeatedly used in each of the 9 groups. One group was not medicated. Cats in the other groups received 2 mg/kg BW xylazine intramuscularly, and saline (as the control); 160 μg/kg BW prazosin; or 40, 160, or 480 μg/kg BW atipamezole or yohimbine intravenously 0.5 h later. Urine and blood samples were collected 10 times over 8 h. Urine volume, pH, and specific gravity; plasma arginine vasopressin (AVP) concentration; and creatinine, osmolality, and electrolyte values in both urine and plasma were measured. Both atipamezole and yohimbine antagonized xylazine-induced diuresis, but prazosin did not. The antidiuretic effect of atipamezole was more potent than that of yohimbine but not dose-dependent, in contrast to the effect of yohimbine at the tested doses. Both atipamezole and yohimbine reversed xylazine-induced decreases in both urine specific gravity and osmolality, and the increase in free water clearance. Glomerular filtration rate, osmolar clearance, and plasma electrolyte concentrations were not significantly altered. Antidiuresis of either atipamezole or yohimbine was not related to the area under the curve for AVP concentration, although the highest dose of both atipamezole and yohimbine increased plasma AVP concentration initially and temporarily, suggesting that this may in part influence antidiuretic effects of both agents. The diuretic effect of xylazine in cats may be mediated by α2-adrenoceptors but not α1-adrenoceptors. Atipamezole and yohimbine can be used as antagonistic agents against xylazine-induced diuresis in clinically normal cats.

  7. Function of cGMP-dependent protein kinase II in volume load-induced diuresis.

    PubMed

    Schramm, Andrea; Schinner, Elisabeth; Huettner, Johannes P; Kees, Frieder; Tauber, Philipp; Hofmann, Franz; Schlossmann, Jens

    2014-10-01

    Atrial natriuretic peptide (ANP)/cGMPs cause diuresis and natriuresis. Their downstream effectors beyond cGMP remain unclear. To elucidate a probable function of cGMP-dependent protein kinase II (cGKII), we investigated renal parameters in different conditions (basal, salt diets, starving, water load) using a genetically modified mouse model (cGKII-KO), but did not detect any striking differences between WT and cGKII-KO. Thus, cGKII is proposed to play only a marginal role in the adjustment of renal concentration ability to varying salt loads without water restriction or starving conditions. When WT mice were subjected to a volume load (performed by application of a 10-mM glucose solution (3% of BW) via feeding needle), they exhibited a potent diuresis. In contrast, urine volume was decreased significantly in cGKII-KO. We showed that AQP2 plasma membrane (PM) abundance was reduced for about 50% in WT upon volume load, therefore, this might be a main cause for the enhanced diuresis. In contrast, cGKII-KO mice almost completely failed to decrease AQP2-PM distribution. This significant difference between both genotypes is not induced by an altered p-Ser256-AQP2 phosphorylation, as phosphorylation at this site decreases similarly in WT and KO. Furthermore, sodium excretion was lowered in cGKII-KO mice during volume load. In summary, cGKII is only involved to a minor extent in the regulation of basal renal concentration ability. By contrast, cGKII-KO mice are not able to handle an acute volume load. Our results suggest that membrane insertion of AQP2 is inhibited by cGMP/cGKII.

  8. Pharmacologic options available to treat symptomatic intradialytic hypotension.

    PubMed

    Perazella, M A

    2001-10-01

    Treatment of symptomatic intradialytic hypotension (IDH) is a difficult task for the practicing nephrologist. Minimizing patient factors that precipitate IDH as well as dialysis procedure-related components that lower blood pressure are the initial approaches to this problem. However, despite these maneuvers, hypotension often persists in a group of high-risk patients. Pharmacologic interventions are often used to reduce IDH. Unfortunately, many of the available therapies are marginally effective and/or poorly tolerated. A few therapies appear to be efficacious and well tolerated-carnitine, sertraline, and midodrine. This article reviews the various pharmacologic therapies used for IDH and makes recommendations for treatment of this difficult problem.

  9. Recent advances in the treatment of orthostatic hypotension

    NASA Technical Reports Server (NTRS)

    Robertson, D.; Davis, T. L.

    1995-01-01

    Orthostatic hypotension is a fall in blood pressure on standing that causes symptoms of dizziness, visual changes, and discomfort in the head and neck. The goal of treatment is the improvement of the patient's functional capacity, rather than a target blood pressure. For treatment to be successful, it must be individualized. Non-pharmalogic interventions include carefully managed exercise, scheduled activities, and monitoring of the environmental temperature. Agents such as fludrocortisone, midodrine, and epoetin alfa offer successful pharmacologic interventions. Although these measures ease the symptoms of orthostatic hypotension, current approaches neither reverse nor stabilize the disease process in autonomic disorders.

  10. Acarbose improved severe postprandial hypotension in a patient with diabetes mellitus.

    PubMed

    Sasaki, E; Goda, K; Nagata, K; Kitaoka, H; Ohsawa, N; Hanafusa, T

    2001-01-01

    Postprandial hypotension (PPH) is defined as a decrease of systolic blood pressure by more than 20 mmHg after meals. Severe PPH is a troublesome diabetic complication, which has no established means of treatment. We encountered a patient who had diabetes mellitus complicated by severe PPH and attempted to treat this problem using several medications (octreotide, midodrine hydrochloride, and acarbose). A 58-year-old male with diabetic triopathy complained of orthostatic dizziness and vertigo after meals. The blood pressure was monitored for 24 h with an ambulatory blood pressure monitor, revealing that the systolic blood pressure decreased markedly after breakfast and dinner by 45 and 50 mmHg, respectively. PPH was not improved by a subcutaneous injection of octreotide. Administration of midodrine hydrochloride reduced the frequency of hypotensive episodes from twice to once daily, but the magnitude of the postprandial fall in blood pressure was still around 30 mmHg. After the patient started to receive acarbose therapy, the postprandial fall in blood pressure was diminished to 18 mmHg and his symptoms largely disappeared. For the treatment of PPH in diabetic patients, our experience suggests that it may be appropriate to try first on alpha-glucosidase inhibitor like acarbose.

  11. The role of nitric oxide in saline-induced natriuresis and diuresis in rats.

    PubMed

    Noonan, W T; Banks, R O

    1999-09-01

    This study was designed to determine to what extent nitric oxide (NO) mediates the natriuretic and diuretic responses to acute isotonic saline (0.9 gram % NaCl) volume expansion (SVE, 0.5 ml min-1 kg-1). Studies were performed on 49 pentobarbital anesthetized (65 mg/kg) female Sprague-Dawley rats with or without a NO synthase inhibitor, Nomega-nitro-L-arginine (LNA). Group 1 received saline at 27 microliter/min for 1 hr (baseline) and then SVE for 1 hr; Groups 2-4 received LNA at 10, 150, and 200 microgram kg-1 min-1, respectively, for 1 hr followed by LNA + SVE. To determine to what extent inhibition of NOS would reverse an ongoing SVE-induced natriuresis and diuresis, Group 5 was saline-volume-expanded for hours 1 and 2 whereas Group 6 was administered SVE during the first hour and then SVE + 150 microgram kg -1 min-1 LNA during the second hour. SVE caused a significant (P < 0.05) increase in the glomerular filtration rate (GFR) of Group 1 and the LNA-treated rats (Groups 2-4). This SVE-induced increase in the GFR occurred despite the fact that baseline GFR was significantly lower in the two groups of rats that were infused with the highest doses of LNA (Groups 3-4). SVE was also associated with similar increases in urine flow rate, sodium and potassium excretion, and total osmolar excretion in Groups 1-4. On the other hand, mean arterial pressure (MAP) was significantly higher in Group 2 during SVE + LNA and during the baseline as well as during the SVE periods in Groups 3-4; MAP was also significantly elevated in Group 6 during SVE + LNA. Thus, despite the fact that MAP was higher in LNA-treated rats, sodium and urine flow rates were the same as in Group 1 (i.e., there was no evidence of a pressure natriuresis or diuresis in these animals). Along these lines, there was a small but significant positive linear correlation coefficient (r = 0.41, P = 0.05) between sodium excretion values and corresponding MAP values in SVE control rats but not in Groups 3-4 during

  12. [Drinking water and urinary stones. Which drinking water and which modalities of diuresis?].

    PubMed

    Hubert, Jacques; Hubert, Claire; Jungers, Paul; Daudon, Michel; Hartemann, Philippe

    2002-09-01

    Urologists frequently advise a high fluid intake to their patients with calcium stones, but apart from this simple advice, they often have few convincing arguments. This article describes the various types of drinking water available in France (mineral water, spring water, tap water), the legislation concerning drinking water, and the ions that must be taken into account for long-term forced diuresis. After studying their composition and adapting the dietary advice (particularly concerning dairy foods) to this ionic composition, various types of water can be advised to patients, including tap water, most types of spring water, but not all mineral waters.

  13. High blood pressure and syncope: orthostatic hypotension as a link.

    PubMed

    Rafanelli, Martina; Ungar, Andrea

    2016-06-22

    The prevalence of hypertension increases with the age. Diagnostic criteria are the same as for the young, but in older adults isolated systolic hypertension is more frequent, due to loss of vascular compliance. Blood pressure should be measured on both sides in the seated position, moreover in the supine and upright position to detect orthostatic hypotension. Ambulatory blood pressure monitoring is useful to detect white coat hypertension and masked hypertension, to tailor the treatment and search for diurnal and nocturnal blood pressure pattern abnormalities. Given that frailty can affect the relationship between blood pressure and mortality, the clinician should properly evaluate and monitor physical performance and cognitive status, throughout specific tools, as the Fried Frailty Phenotype, aiming at a systolic blood pressure target between 130 and 150 mmHg. Before starting hypotensive drugs, a careful risk and benefits' evaluation should be performed given the high risk of hypertension and hypotension consequences and the frequent coexistence of orthostatic hypotension, which predisposes to syncope and falls.

  14. Central Methysergide Prevents Renal Sympathoinhibition and Bradycardia during Hypotensive Hemorrhage

    NASA Technical Reports Server (NTRS)

    Veelken, Roland; Johnson, Kim; Scrogin, Karie E.

    1998-01-01

    Central methysergide prevents renal sympathoinhibition and bradycardia during hypotensive hemorrhage. Mean arterial pressure (MAP), heart rate (HR), and renal sympathetic nerve activity (RSNA) were measured in conscious rats during either hemorrhage or cardiopulmonary receptor stimulation with phenylbiguanide (PBG) after intracerebroventricular injection of the 5-HT1/5-HT2-receptor antagonist, methysergide (40 microg). Progressive hemorrhage caused an initial rise (109 +/- 33%) followed by a fall in RSNA (-60 +/- 7%) and a fall in HR (-126 +/- 7 beats/min). Methysergide delayed the hypotension and prevented both the sympathoinhibitory and bradycardic responses to hemorrhage. Systemic 5-HT3-receptor blockade did not influence responses to hemorrhage. The PBG infusion caused transient depressor(-25 +/- 6 mmHg), bradycardic (-176 +/- 40 beats/min), and renal sympathostimulatory (182 +/-47% baseline) responses that were not affected by central methysergide (-20 +/- 6 mmHg, -162 +/- 18 beats/min, 227 +/- 46% baseline). These data indicate that a central serotonergic receptor-mediated component contributes to the sympathoinhibitory and bradycardic responses to hypotensive hemorrhage in conscious rats. Furthermore, the same central 5-HT-receptor populations involved in reflex responses to hypotensive hemorrhage probably do not mediate the sympathoinhibitory response to cardiopulmonary chemosensitive 5-HT3 receptors.

  15. Midodrine as a Countermeasure for Post-spaceflight Orthostatic Hypotension

    NASA Technical Reports Server (NTRS)

    Platts, Steven H.; Ziegler, Michael G.; Waters, Wendy W.; Meck, Janice V.

    2007-01-01

    Up to 30 % of astronauts exhibit post-spaceflight orthostatic hypotension due to inadequate norepinephrine release during upright posture following short duration spaceflight. We hypothesize that the (alpha)1-adrenergic agonist midodrine will be an effective countermeasure. This study is being conducted in 2 phases. The first phase is complete and consisted testing six short duration crew members. All of these subjects participated in preflight and postflight tilt testing on a control flight as well as on the test flights, where midodrine was administered after landing, 1 hour before testing. Hemodynamic variables were compared between the 2 flights. Midodrine improved stroke volume, cardiac output, systolic pressure and heart rate, without increasing vascular resistance. None of these subjects experienced orthostatic hypotension on landing day. Phase II is similar to phase I, except that midodrine is ingested in flight (near TIG) and the tilt test is performed immediately after landing on the CTV. One crewmember has completed phase II testing. This crewmember had no evidence of orthostatic hypotension or presyncope, four additional crewmembers have volunteered for this study. To date, midodrine has been shown to be a safe and effective countermeasure to post-spaceflight orthostatic hypotension.

  16. Intracranial hypotension: the nonspecific nature of MRI findings.

    PubMed

    Bruera, O C; Bonamico, L; Giglio, J A; Sinay, V; Leston, J A; Figuerola, M L

    2000-01-01

    We present three patients who complained of postural headache related to different types of intracranial hypotension: spontaneous or primary, and secondary, but presenting the same findings on brain magnetic resonance imaging. Diffuse pachymeningeal gadolinium enhancement supports the belief that the enhancement is a nonspecific meningeal reaction to low pressure.

  17. Hypotension does not alter the antinociceptive effect of nifedipine.

    PubMed

    Wong, C H; Wu, W H; Zbuzek, V K

    1998-01-01

    We explored the relationship between antinociceptive and hypotensive effects of nifedipine (NIF) injected intraperitoneally ( ip, 15 mg/kg) and epidurally (epi, 20 microM), as compared to verapamil (VER, 10 mg/kg ip) and nitroglycerin (NTG, 0.1 and 0.15 mg/kg ip). The systolic blood pressure (BP) and tail-flick (TF) latencies were measured simultaneously every 10 min for 2 hours and individual values of both measurements were correlated. The highest antinociceptive as well as hypotensive effects were both measured in the group receiving NIF epi., with the correlation coefficient r2=0.2878. Injected ip., NIF revealed similar antinociceptive effect, whereas the other studied drugs were not effective. As to the degree of hypotensive activity, NIF epi was followed by VER, NTG 0.1, NIF ip. and NTG 0.15. No significant correlation was found between BP and TF latencies in any group receiving the drugs. We concluded that the antinociceptive response, measured by the tail-flick technique, is independent of the hypotensive activity of the studied drugs, including NIF.

  18. Treatment of Idiopathic Intracranial Hypotension With Tea: A Case Report

    PubMed Central

    Petramfar, Peyman; Mohammadi, S. Saeed; Hosseinzadeh, Farideh

    2016-01-01

    Introduction The syndrome of spontaneous intracranial hypotension has been increasingly diagnosed since its discovery through magnetic resonance imaging (MRI). It is a rare syndrome that is due to the leakage of cerebrospinal fluid (CSF) from a tear in the dura and can occur at any age, even among adolescents, but is most frequently seen among females in late middle age. Case Presentation Here, we describe a 32-year-old woman with a two-month history of headaches and occasional nausea and vomiting (N/V). MRI without gadolinium was normal, but meningeal enhancement was seen in MRI with gadolinium. The lumbar puncture revealed a low opening pressure. Computed tomography myelography (CT myelography) showed no leakage; Therefore, idiopathic intracranial hypotension was diagnosed. Treatment was started using tea, and the patient’s headache got significantly better in about a day. Conclusions Conservative therapy, such as bed rest and caffeine treatment with eight cups of tea daily, yielded a significant improvement in our patient. Effectively, the patient constitutes a case of idiopathic intracranial hypotension due to undetectable CSF leakage or hyper-absorption, with good response to conservative management through tea-drinking. Further investigations with an appropriate sample size are needed in order to confirm this intervention in the treatment of idiopathic intracranial hypotension. PMID:27621920

  19. Acute Electrocardiographic ST Segment Elevation May Predict Hypotension in a Swine Model of Severe Cyanide Toxicity

    DTIC Science & Technology

    2012-04-21

    induced shock, 30 swine were anesthetized and monitored and then intoxicated with a continuous cyanide infusion until severe hypotension (50 % of...TOXICOLOGY INVESTIGATION Acute Electrocardiographic ST Segment ElevationMay Predict Hypotension in a Swine Model of Severe Cyanide Toxicity Tylan A...Toxicology 2012 Abstract Cyanide causes severe cardiac toxicity resulting in tachycardia, hypotension, and cardiac arrest; however, the clinical diagnosis can

  20. Prevention of supine hypotensive syndrome in pregnant women treated with transcranial magnetic stimulation.

    PubMed

    Kim, Deborah Rubin; Wang, Eileen

    2014-08-15

    In our studies of transcranial magnetic stimulation in pregnant women with major depressive disorder, two subjects had an episode of supine hypotensive syndrome and one subject had an episode of dizziness without hypotension. Prevention of the supine hypotensive syndrome in pregnant women receiving transcranial magnetic stimulation is described.

  1. Hypotensive effects of resistance exercises with blood flow restriction.

    PubMed

    Neto, Gabriel R; Sousa, Maria S C; Costa, Pablo B; Salles, Belmiro F; Novaes, Giovanni S; Novaes, Jefferson S

    2015-04-01

    The effects of low-intensity resistance exercise (RE) combined with blood flow restriction (BFR) on blood pressure (BP) are an important factor to be considered because of the acute responses imposed by training. The aim of this study was to compare the hypotensive effect of RE performed with and without BFR in normotensive young subjects. After 1 repetition maximum (1RM) tests, 24 men (21.79 ± 3.21 years; 1.72 ± 0.06 m; 69.49 ± 9.80 kg) performed the following 4 experimental protocols in a randomized order: (a) high-intensity RE at 80% of 1RM (HI), (b) low-intensity RE at 20% of 1RM (LI), (c) low-intensity RE at 20% of 1RM combined with partial BFR (LI + BFR), and (d) control. Analysis of systolic blood pressure (SBP) and diastolic blood pressure (DBP) was conducted over a 60-minute period. The 3 RE protocols resulted in hypotensive SBP (HI = -3.8%, LI = -3.3%, LI + BFR = -5.5%) responses during the 60 minutes (p ≤ 0.05). The LI + BFR protocol promoted hypotensive (-11.5%) responses in DBP during the 60 minutes (p ≤ 0.05), and both the HI and LI + BFR protocols resulted in mean blood pressure (MBP) hypotension between 30 (-7.0%, -7.7%) and 60 minutes (-3.6%, -8.8%), respectively. In conclusion, postexercise hypotension may occur after all 3 exercise protocols with greater reductions in SBP after HI and LI + BFR, in DBP after LI + BFR, and in MBP after HI and LI + BFR protocols.

  2. A pharmacokinetic/pharmacodynamic model capturing the time course of torasemide-induced diuresis in the dog.

    PubMed

    Paulin, A; Schneider, M; Dron, F; Woehrlé, F

    2016-12-01

    A pharmacokinetic/pharmacodynamic modelling approach was used to determine a dosage regimen which maximizes diuretic efficiency of torasemide in dogs. Kinetic profiles of plasma concentration, torasemide excretion rate in urine (TERU) and diuresis were investigated in 10 dogs after single oral administrations at 3 dose levels, 0.2, 0.8 and 1.6 mg/kg, and an intravenous injection of 0.2 mg/kg. Endogenous regulation was evidenced by a proteresis loop between TERU and diuresis. To describe the diuresis-time profile, TERU served as input into a turnover model with inhibition of loss of response, extended by a moderator acting on both loss and production of response. Estimated maximum inhibition of loss of response, Imax , was 0.984 showing that torasemide is an efficacious diuretic able to suppress almost total water reabsorption. A TERU50, value producing half of Imax , of 1.45 μg/kg/h was estimated from the model. Pharmacokinetic and pharmacodynamic parameters were used to simulate the torasemide dose-effect relationship after oral administration. Model predictions were in good agreement with diuresis measured in a validation study conducted in 10 dogs, which were administered oral doses of 0.15, 0.4, 0.75, 1.5 and 4.5 mg/kg for 5 days. Finally, oral dose associated with the highest daily diuretic efficiency was predicted to be 0.1 mg/kg.

  3. A case of isolated ACTH deficiency who developed autoimmune-mediated hypothyroidism and impaired water diuresis during glucocorticoid replacement therapy.

    PubMed

    Kageyama, Y

    2000-12-01

    A case of isolated ACTH deficiency who developed autoimmune-mediated hypothyroidism and still showed impaired water diuresis during glucocorticoid replacement therapy is reported. A 45-year-old woman was initially admitted for nausea, vomiting, and general malaise. Her serum sodium and plasma osmolality, ACTH and cortisol values were low, but her urine osmolality was high. Other pituitary hormone levels, thyroid hormone levels, and a computed tomogram of the pituitary gland were normal. The patient was treated with hydrocortisone and followed in the outpatient clinic; however, she was lost to follow up 18 months after admission. Three years later she presented with hypoglycemia and hyponatremia. Her serum or plasma ACTH, FT3, FT4, cortisol levels were low and her serum TSH level was high. Pituitary stimulation tests revealed a blunted response of ACTH to CRH and an exaggerated response of TSH to TRH. Plasma ADH was inappropriately high, and a water-loading test revealed impaired water diuresis and poor suppression of ADH. Although ADH was suppressed, impaired water diuresis was observed in the water loading test after hydrocortisone supplementation. Thyroxine supplementation completely normalized the water diuresis. Her outpatient clinic medical records revealed a gradual increase in TSH levels during follow up, indicating that she had developed hypothyroidism during glucocorticoid replacement therapy. The hyponatremia on the first admission was due to glucocorticoid deficiency, whereas the hyponatremia on the second admission was due to combined deficiencies of glucocorticoid and thyroid hormones.

  4. New optimized piperamide analogues with potent in vivo hypotensive properties.

    PubMed

    de Mattos Duarte, Carolina; Verli, Hugo; de Araújo-Júnior, João Xavier; de Medeiros, Isac Almeida; Barreiro, Eliezer J; Fraga, Carlos Alberto Manssour

    2004-12-01

    We describe herein the structural optimization of new piperamide analogues, designed from two natural prototypes, piperine 1 and piperdardine 2, obtained from Piper tuberculatum Jacq. (Piperaceae). Molecular modeling studies using semiempirical AM1 method were made in order to establish rational modifications to optimize them by molecular simplification. The targeted compounds (10) and (11) were respectively obtained using benzaldehyde (12) and para-anisaldehyde (13) as starting materials. 1H NMR spectra showed that the target compounds were diastereoselectively obtained as the (E)-isomer, the same geometry of the natural prototypes. These new synthetic amides presented significant hypotensive effects in cardiovascular essays using in vivo methodologies. Compound 11 (N-[5-(4'-methoxyphenyl)-2(E)-pentenoyl]thiomorpholine) showed a potency 10,000 times greater than its prototype 5, evidencing an optimization of the molecular architecture for this class of hypotensive drug candidates.

  5. Persistent orthostatic headache without intracranial hypotension: which treatment?

    PubMed

    Curone, M; Cecchini, A Proietti; Chiapparini, L; D'Amico, D

    2015-05-01

    Orthostatic headache can be the leading symptom of intracranial hypotension, however, not all orthostatic headaches are due to cerebrospinal fluid leaks and these forms can be a clinical problem, especially for treatment. Aim of this study was to review patients with persistent orthostatic headache in whom a detailed head and spinal MRI follow-up did not reveal any sign of intracranial hypotension and to evaluate which treatment can be considered the first choice. Patients admitted to our headache center for evaluation of persistent orthostatic headache and followed after first admission with clinical and neuroradiological controls were systematically reviewed. 11 patients (7 M, 4 F) followed in a period lasted from 10 months up to 2 years were studied. Six patients (54, 5 %) reported a MRI performed previously elsewhere with a suspect diagnosis of intracranial hypotension which was not confirmed at MRI at our hospital such as during the radiological follow-up. Three patients (27.2 %) had developed orthostatic headache short after a neck or head trauma with no evidence of neuroradiological pathological signs and two patients (18 %) had a previous history of psychiatric disorder. We administrated antidepressants in five patients, atypical neuroleptic in three patients, association of antidepressant and antipsychotic in one patient and muscle relaxants in two cases. All patients showed a certain improvement of headache in the weeks after introduction of the pharmacological treatment; six (54, 5 %) had pain relief during the follow-up and five (45, 5 %) were pain free at the last clinical control. We found out that patients with the best outcome were the ones treated with antidepressants. Persistent orthostatic headache without any neuroradiological sign of intracranial hypotension is a challenging problem for clinicians. Although the International Classification of Headache Disorders (ICHD-3 beta version) criteria suggests the possibility of epidural blood patch in

  6. [Case of ischemic heart disease resulting from persistent diuresis after giant ovarian tumor resection].

    PubMed

    Sata, Naho; Satoh, Masaaki; Seo, Norimasa

    2010-02-01

    A patient with a giant ovarian tumor weighing about 7 kg was successfully removed by operation. However, her ECG demonstrated ischemic changes after the operation. We report a case of ischemic heart disease due to persistent diuresis after giant ovarian tumor resection. A 75-year-old, 56.5 kg, 143.5 cm woman was admitted to our hospital for ovarian tumor resection. The preoperative ECG showed normal sinus rhythm and no ischemic changes. Both general anesthesia and epidural anesthesia were planed. An epidural catheter was inserted at T12-L1. Anesthesia was induced with propofol 100 mg, fentanyl 100 microg and vecuronium 8 mg under 100% oxygen inhalation. General anesthesia was maintained with sevoflurane while epidural anesthesia was achieved using 0.375% ropivacaine 6 ml. During the operation, blood pressure was 90-110/70-80 mmHg, with SaO2, 100% and heart rate, 70-80 beats x min(-1). The content of tumor was suctioned for 30 minutes. Surgery was successfully finished without any other incidence. After extubation, her ECG changed to atrial fibrillation from normal sinus rhythm and showed ST-T depression. And then her systolic blood pressure became 80 mmHg or below, but we found continued diuresis at about 10 ml x kg(-1) x hr(-1) for over 2 hr. The total of 7 unit vasopressin was intermittently given for vasoconstriction and antidiuresis. Her hemodynamic was immediately restored, and ECG turned to normal ST-T. The patient had uneventful postoperative recovery.

  7. Chronic intrarenal insulin replacement reverses diabetes mellitus-induced natriuresis and diuresis.

    PubMed

    Manhiani, M Marlina; Duggan, A Daniel; Wilson, Hunter; Brands, Michael W

    2012-02-01

    We showed recently that sustained natriuresis in type 1 diabetic dogs was attributed to the decrease in insulin rather than the hyperglycemia alone. The sodium-retaining action of insulin appeared to require hyperglycemia, and it completely reversed the diabetic natriuresis and diuresis. This study tested whether the sodium-retaining effect was attributed to direct intrarenal actions of insulin. Alloxan-treated dogs (D; n=7) were maintained normoglycemic using 24-h/d IV insulin replacement. After control measurements, IV insulin was decreased to begin a 6-day diabetic period. Blood glucose increased from 84±6 mg/dL to an average of 428 mg/dL on days 5 and 6, sodium excretion increased from 74±8 to 98±7 meq/d over the 6 days, and urine volume increased from 1645±83 to 2198±170 mL/d. Dir dogs (n=7) were subjected to the same diabetic regimen, but, in addition, insulin was infused continuously into the renal artery at 0.3 mU/kg per minute during the 6-day period. This did not affect plasma insulin. Blood glucose increased from 94±10 mg/dL to an average of 380 mg/dL on days 5 and 6, but sodium excretion averaged 76±5 and 69±8 meq/d during control and diabetes mellitus, respectively. The diuresis also was prevented. Glomerular filtration rate increased only in Dir dogs, and there was no change in mean arterial pressure in either group. This intrarenal insulin infusion had no effect on sodium or volume excretion in normal dogs. Intrarenal insulin replacement in diabetic dogs caused a sustained increase in tubular reabsorption that completely reversed diabetic natriuresis. Insulin plus glucose may work to prevent salt wasting in uncontrolled type 2 diabetes mellitus.

  8. Gastrin and D1 dopamine receptor interact to induce natriuresis and diuresis.

    PubMed

    Chen, Yue; Asico, Laureano D; Zheng, Shuo; Villar, Van Anthony M; He, Duofen; Zhou, Lin; Zeng, Chunyu; Jose, Pedro A

    2013-11-01

    Oral NaCl produces a greater natriuresis and diuresis than the intravenous infusion of the same amount of NaCl. Gastrin is the major gastrointestinal hormone taken up by renal proximal tubule (RPT) cells. We hypothesized that renal gastrin and dopamine receptors interact to synergistically increase sodium excretion, an impaired interaction of which may be involved in the pathogenesis of hypertension. In Wistar-Kyoto rats, infusion of gastrin induced natriuresis and diuresis, which was abrogated in the presence of a gastrin (cholecystokinin B receptor [CCKBR]; CI-988) or a D1-like receptor antagonist (SCH23390). Similarly, the natriuretic and diuretic effects of fenoldopam, a D1-like receptor agonist, were blocked by SCH23390, as well as by CI-988. However, the natriuretic effects of gastrin and fenoldopam were not observed in spontaneously hypertensive rats. The gastrin/D1-like receptor interaction was also confirmed in RPT cells. In RPT cells from Wistar-Kyoto but not spontaneously hypertensive rats, stimulation of either D1-like receptor or gastrin receptor inhibited Na(+)-K(+)-ATPase activity, an effect that was blocked in the presence of SCH23390 or CI-988. In RPT cells from Wistar-Kyoto and spontaneously hypertensive rats, CCKBR and D1 receptor coimmunoprecipitated, which was increased after stimulation of either D1 receptor or CCKBR in RPT cells from Wistar-Kyoto rats; stimulation of one receptor increased the RPT cell membrane expression of the other receptor, effects that were not observed in spontaneously hypertensive rats. These data suggest that there is a synergism between CCKBR and D1-like receptors to increase sodium excretion. An aberrant interaction between the renal CCK BR and D1-like receptors (eg, D1 receptor) may play a role in the pathogenesis of hypertension.

  9. Guancydine, a new hypotensive agent with complex action.

    PubMed

    Hărăgus, S T; Uza, G; Duncea, C

    1977-01-01

    Guancydine (1-cyano-3-tert-amylguanidine) lowered within normal limits the tensional values in an interval of four hours after its administration in eight out of nine hypertensive patients under experiment. The hypotensive effect of a single oral dose of 500-750 mg persists for about 6-7 hours after its administration. Guancydine does not impair the vasopressor response to angiotensin II but reduces the action of this peptide on the excretion of water, Na, K and Ca through urine. The hypotensive effect of Guancydine is associated with a decrease of platelet adhesiveness and an activation of fibrinolysis. In view of this fact, Guancydine might play a role in the prophylaxis of complications of arterial hypertension - atherosclerosis and trombosis. The increase of venous blood oxygenation after Guancydine could be attributed to the opening of arterio-venous shunts or to the reduction of tissular extraction of oxygen. Guancydine does not seem to be toxic. It produced, in some patients, slight headache and orthostatic hypotension, especially during the first hours after administration.

  10. Hemofiltration and Hemodiafiltration Reduce Intradialytic Hypotension in ESRD

    PubMed Central

    Altieri, Paolo; Andrulli, Simeone; Bolasco, Piergiorgio; Sau, Giovanna; Pedrini, Luciano A.; Basile, Carlo; David, Salvatore; Feriani, Mariano; Montagna, Giovanni; Di Iorio, Biagio Raffaele; Memoli, Bruno; Cravero, Raffaella; Battaglia, Giovanni; Zoccali, Carmine

    2010-01-01

    Symptomatic intradialytic hypotension is a common complication of hemodialysis (HD). The application of convective therapies to the outpatient setting may improve outcomes, including intradialytic hypotension. In this multicenter, open-label, randomized controlled study, we randomly assigned 146 long-term dialysis patients to HD (n = 70), online predilution hemofiltration (HF; n = 36), or online predilution hemodiafiltration (HDF; n = 40). The primary end point was the frequency of intradialytic symptomatic hypotension (ISH). Compared with the run-in period, the frequency of sessions with ISH during the evaluation period increased for HD (7.1 to 7.9%) and decreased for both HF (9.8 to 8.0%) and HDF (10.6 to 5.2%) (P < 0.001). Mean predialysis systolic BP increased by 4.2 mmHg among those who were assigned to HDF compared with decreases of 0.6 and 1.8 mmHg among those who were assigned to HD and HF, respectively (P = 0.038). Multivariate logistic regression demonstrated significant risk reductions in ISH for both HF (odds ratio 0.69; 95% confidence interval 0.51 to 0.92) and HDF (odds ratio 0.46, 95% confidence interval 0.33 to 0.63). There was a trend toward higher dropout for those who were assigned to HF (P = 0.107). In conclusion, compared with conventional HD, convective therapies (HDF and HF) reduce ISH in long-term dialysis patients. PMID:20813866

  11. Interaction with pyridoxal as a possible mechanism of hydralazine hypotension.

    PubMed

    Vidrio, H

    1990-01-01

    The mechanism by which the antihypertensive vasodilator hydralazine relaxes vascular smooth muscle is unknown. The drug interacts with pyridoxal and can produce B6 deficiency; it also inhibits a number of enzymes requiring pyridoxal as a cofactor, but there is no apparent relation between its enzymatic and blood pressure effects. To explore the possibility of a hydralazine-pyridoxal interaction at a nonenzymatic site, the acute hypotensive response to hydralazine was determined by tail cuff blood pressure (BP) measurements in conscious normotensive rats pretreated or not pretreated with pyridoxine. Other animals were pretreated with isoniazid, a drug also capable of reacting with pyridoxal. Responses to hydralazine were diminished by pyridoxine and enhanced by isoniazid; those to the vasodilator diazoxide or to the alpha-adrenergic blocker zolertine were unaffected by such pretreatments. The inhibitory effect of pyridoxine was absent when rats were pretreated with the calcium antagonists verapamil or cinnarizine. Hydralazine hypotension in anesthetized rats was also reduced by pyridoxal pretreatment. These results suggest that at least part of hydralazine-induced hypotension may be related to interaction with pyridoxal, possibly through interference with an effect of the vitamer on calcium and/or sodium transport into vascular smooth muscle.

  12. Low-Volume Intense Exercise Elicits Post-exercise Hypotension and Subsequent Hypervolemia, Irrespective of Which Limbs Are Exercised

    PubMed Central

    Graham, Matthew J.; Lucas, Samuel J. E.; Francois, Monique E.; Stavrianeas, Stasinos; Parr, Evelyn B.; Thomas, Kate N.; Cotter, James D.

    2016-01-01

    Introduction: Exercise reduces arterial and central venous blood pressures during recovery, which contributes to its valuable anti-hypertensive effects and to facilitating hypervolemia. Repeated sprint exercise potently improves metabolic function, but its cardiovascular effects (esp. hematological) are less well-characterized, as are effects of exercising upper versus lower limbs. The purposes of this study were to identify the acute (<24 h) profiles of arterial blood pressure and blood volume for (i) sprint intervals versus endurance exercise, and (ii) sprint intervals using arms versus legs. Methods: Twelve untrained males completed three cycling exercise trials; 50-min endurance (legs), and 5*30-s intervals using legs or arms, in randomized and counterbalanced sequence, at a standardized time of day with at least 8 days between trials. Arterial pressure, hemoglobin concentration and hematocrit were measured before, during and across 22 h after exercise, the first 3 h of which were seated rest. Results: The post-exercise hypotensive response was larger after leg intervals than endurance (AUC: 7540 ± 3853 vs. 3897 ± 2757 mm Hg·min, p = 0.049, 95% CI: 20 to 6764), whereas exercising different limbs elicited similar hypotension (arms: 6420 ± 3947 mm Hg·min, p = 0.48, CI: −1261 to 3896). In contrast, arterial pressure at 22 h was reduced after endurance but not after leg intervals (−8 ± 8 vs. 0 ± 7 mm Hg, p = 0.04, CI: 7 ± 7) or reliably after arm intervals (−4 ± 8 mm Hg, p = 0.18 vs. leg intervals). Regardless, plasma volume expansion at 22 h was similar between leg intervals and endurance (both +5 ± 5%; CI: −5 to 5%) and between leg and arm intervals (arms: +5 ± 7%, CI: −8 to 5%). Conclusions: These results emphasize the relative importance of central and/or systemic factors in post-exercise hypotension, and indicate that markedly diverse exercise profiles can induce substantive hypotension and subsequent hypervolemia. At least for endurance

  13. Marking nut anaphylaxis

    PubMed Central

    Kral, Anita Christine; Hayball, John; Smith, William B

    2016-01-01

    Marking nut Semecarpus anacardium, so-called because it contains a pigment that has been used in the past to mark fabrics, is a known cause of contact hypersensitivity. It may be ingested as an ingredient of some traditional Hindi foods. We describe the first reported case of anaphylaxis to marking nut. PMID:27489793

  14. The use of vasopressin in the setting of recalcitrant hypotension due to calcium channel blocker overdose.

    PubMed

    Kanagarajan, Karthikeyan; Marraffa, Jeanna M; Bouchard, Nicole C; Krishnan, Padmanabhan; Hoffman, Robert S; Stork, Christine M

    2007-01-01

    Treatment of hypotension caused by calcium channel blocker overdose (CCB) remains a challenge. We describe the successful use of vasopressin in two patients with massive CCB overdoses in whom hypotension was unresponsive to calcium, glucagon, insulin, and conventional vasopressor therapies. While various modes of treatments have been used to treat the hypotension of CCB overdose, this is the first report to our knowledge of the successful use of vasopressin in this clinical setting.

  15. GCF Mark IV development

    NASA Technical Reports Server (NTRS)

    Mortensen, L. O.

    1982-01-01

    The Mark IV ground communication facility (GCF) as it is implemented to support the network consolidation program is reviewed. Changes in the GCF are made in the area of increased capacity. Common carrier circuits are the medium for data transfer. The message multiplexing in the Mark IV era differs from the Mark III era, in that all multiplexing is done in a GCF computer under GCF software control, which is similar to the multiplexing currently done in the high speed data subsystem.

  16. Spontaneous Intracranial Hypotension: An Etiology for Consciousness Disorder and Coma.

    PubMed

    Collange, Olivier; Wolff, Valérie; Cebula, Hélène; Pradignac, Alain; Meyer, Alain; Kindo, Michel; Diemunsch, Pierre; Proust, François; Mertes, Paul-Michel; Kremer, Stéphane

    2016-11-15

    We report 3 cases of spontaneous intracranial hypotension (SIH) associated with consciousness disorder and coma. In patients, SIH was suspected on a computed tomography scan and diagnosed by cerebral magnetic resonance imaging (MRI). Spinal MRI confirmed cerebrospinal fluid leakage. SIH should be seen as an underestimated cause of consciousness disorder and coma, especially in patients with a history of orthostatic headache, spinal injury, or oculomotor signs. Computed tomography scans should be examined for signs of SIH before operating on patients with a spontaneous subdural hematoma. Brain and spine MRI should be performed when SIH is suspected. Our 3 patients have shown good recovery without any neurological sequelae.

  17. Spontaneous Intracranial Hypotension Associated with Kinetic Tremor and Ataxia

    PubMed Central

    Salazar, Richard

    2016-01-01

    Background Spontaneous intracranial hypotension (SIH) is a clinically variable syndrome caused by low cerebrospinal fluid (CSF) pressure due to a non-traumatic CSF leak. Phenomenology Shown This case describes a 68-year-old gentleman who presents with chronic and slightly progressive kinetic tremor of bilateral hands associated with gait ataxia and gait start hesitation. Educational Value This case underscores the importance of having a high index of suspicion for the diagnosis of SIH when encountering a patient presenting with late-onset progressive kinetic tremor and gait ataxia syndrome. PMID:27351232

  18. The Management of Orthostatic Hypotension in Parkinson’s Disease

    PubMed Central

    Sánchez-Ferro, Álvaro; Benito-León, Julián; Gómez-Esteban, Juan Carlos

    2013-01-01

    Orthostatic hypotension (OH) is a common and disabling symptom affecting Parkinson’s disease (PD) patients. We present the effect of the different therapies commonly used to manage PD on this clinical manifestation. For this purpose, we describe the relationship between OH and the current treatments employed in PD, such as L-DOPA, dopaminergic agonists, and continuous dopaminergic stimulation therapies. Additionally, we review the therapeutic measures that could be used to ameliorate OH. There are different approaches to deal with this manifestation, including pharmacological and non-pharmacological treatments, although none of them is specifically aimed for treating OH in PD. PMID:23772219

  19. Early experiences of vasodilators and hypotensive anesthesia in children.

    PubMed

    Brown, T C K

    2012-07-01

    The physiological application of OHMS LAW explains the basis of hypotensive anesthesia. V = IR translates into: Pressure = Flow × Resistance or Blood pressure = Cardiac Output × Peripheral Resistance. If peripheral resistance is reduced by a vasodilator such as sodium nitroprusside (a short acting, vascular smooth muscle relaxant) or phenoxybenzamine (a long acting α adrenoreceptor antagonist), blood pressure will fall and vasoconstriction and bleeding will be reduced. A less desirable alternative to lowering blood pressure could be to reduce cardiac output by suppressing myocardial contractility using a ß(1) adrenoceptor antagonist or an inhalational agent such as isoflurane.

  20. [Case of spontaneous intracranial hypotension associated with depressed consciousness].

    PubMed

    Kato, Takahiro; Nakagawa, Itsuo; Hidaka, Shozo; Okada, Yasunori; Kubo, Takashi; Okamura, Kenta

    2007-04-01

    We experienced a case of spontaneous intracranial hypotension (SIH) complicated with depressed consciousness after its treatment. A 56-year-old woman developed postural headache, and her MRI revealed bilateral chronic subdural hematoma (CSH). After treatment with epidural autolongous blood patch, her headache resolved completely. However, two days after, the patient developed depressed conciousness, and MRI showed brain sagging and downward brain displacement. After management with conservative treatment, including second epidural blood patch and hematoma drainage, the patient became alert and other symptoms resolved gradually. We demonstrated that caution should be taken for the management of SIH, especially in the case associated with CSH.

  1. Pathophysiological basis of orthostatic hypotension in autonomic failure

    NASA Technical Reports Server (NTRS)

    Smit, A. A.; Halliwill, J. R.; Low, P. A.; Wieling, W.

    1999-01-01

    In patients with autonomic failure orthostatic hypotension results from an impaired capacity to increase vascular resistance during standing. This fundamental defect leads to increased downward pooling of venous blood and a consequent reduction in stroke volume and cardiac output that exaggerates the orthostatic fall in blood pressure. The location of excessive venous blood pooling has not been established so far, but present data suggest that the abdominal compartment and perhaps leg skin vasculature are the most likely candidates. To improve the orthostatic tolerance in patients with autonomic failure, protective measures that reduce excessive orthostatic blood pooling have been developed and evaluated. These measures include physical counter-manoeuvres and abdominal compression.

  2. Pressure-natriuresis and -diuresis in transgenic rats harboring both human renin and human angiotensinogen genes.

    PubMed

    Dehmel, B; Mervaala, E; Lippoldt, A; Gross, V; Bohlender, J; Ganten, D; Luft, F C

    1998-12-01

    The hypertensive double transgenic rat harboring both the human renin and human angiotensinogen genes (dTGR) offers a unique opportunity to study the human renin-angiotensin system in an experimental animal model. Since nothing is known about the control of sodium and water excretion in these rats, this study was performed to compare pressure-natriuresis relationships in hypertensive dTGR and normotensive control rats harboring only the human renin gene (hREN), in order to determine how the pressure-natriuresis relationship is reset in hypertensive dTGR. To differentiate between extrinsic and intrinsic renal mechanisms, experiments were performed with and without renal denervation, and with and without infusions of vasopressin, norepinephrine, 17-OH-corticosterone, and aldosterone. Human and rat angiotensinogen and renin mRNA expression were also determined. In hREN without controlled renal function, urine flow and sodium excretion increased from 13 to 169 microl/min per g kidney wet weight (kwt) and from 1 to 30 micromol/min per g kwt, respectively, as renal perfusion pressure was increased from 67 to 135 mmHg. Renal blood flow (RBF) and GFR ranged between 3 to 7 and 0.9 to 1.5 ml/min per g kwt. In dTGR, pressure-natriuresis-diuresis relationships were shifted approximately 40 mmHg rightward. RBF was lower in dTGR than in hREN; GFR was not different. In dTGR with neurohormonal factors controlled, RBF was decreased and pressure-natriuresis-diuresis curves were not different compared to dTGR curves without these interventions. By light microscopy, the kidneys of these 6-wk-old dTGR and hREN rats were normal and indistinguishable. Both human and rat renin and angiotensinogen mRNA were expressed in the kidneys of dTGR. The two renin mRNA were decreased in dTGR, indicating a physiologic downregulation of renin gene expression by high BP. It is concluded that the renal pressure-natriuresis mechanism is reset toward higher pressure levels in dTGR and participates in the

  3. Pilot Study: Colostomy and Urine Collection Protocol for Investigating Potential Inciting Causes of Hen Diuresis Syndrome.

    PubMed

    Jones, Kelli; Turner, Bradley; Brandão, João; Hubbard, Sue Ann; Magee, Danny; Baughman, Brittany; Wills, Robert; Tully, Thomas

    2015-06-01

    Hen diuresis syndrome has emerged over the past 5 yr as a significant cause of mortality in the U.S. broiler breeder industry. The condition affects hens in production and is characterized by transient muscle weakness in the vent region, transient diuresis, and often urate deposits on the skin below the vent. Affected hens are often seen straining to lay an egg, which suggests oviduct contraction is also impaired. Related hen mortality, often reaching 1% or more a week, is believed to be primarily the result of male aggression of the vent region (Turner et al., "Investigating Causes of Excessive Urate Production in Broiler Breeder Hens Associated with Peritonitis and Cannibalism Mortality," Oral Presentation at The American Association of Avian Pathologists Annual Meeting, p. 139, 2010). The exact association between the cause of mortality and this syndrome is unknown, but it may be the consequence of transient partial to full oviduct prolapse, which predisposes or stimulates cannibalism and aggression. Based on unpublished work done prior to this study (Turner et al., ibid.), the evidence suggests the underlying problem is metabolic. We feel that urine collection and analysis is an essential component to understanding this condition. This study serves as a pilot study for future investigations that attempt to identify the nature and cause of the metabolic disturbance through paired urine and serum collection and analysis. For the purpose of this study, a small sample of 10 affected and 10 unaffected birds was used for sample collection. In order to collect pure urine, the birds were surgically colostomized. Colostomy did prove to be a useful means of collecting urine free of feces, and for the purposes of our study it yielded adequate urine samples for analysis. There were statistically relevant urine values observed. Affected birds had a higher presence of blood in the urine, a lower uric acid excretion rate (mg/hr), higher concentration (mEq/L) of urine Na+, and

  4. Effect of hemorrhage on cardiac output, vasopressin, aldosterone, and diuresis during immersion in men

    NASA Technical Reports Server (NTRS)

    Greenleaf, J. E.; Simanonok, K.; Bernauer, E. M.; Wade, C. E.; Keil, L. C.

    1992-01-01

    The purpose of this research was to test the hypotesis that a reduction in blood volume would attenuate or eliminate immersion-induced increases in cardiac output (Q(sub co)) and urine excretion, and to investigate accompanying vasoactive and fluid-electrolyte hormonal responses. Eight men (19-23 yr) were supine during a 2-hr control period in air, and then sat for 5-hr test periods in air at 20 C (dry control, DC); water at 34.5 C (wet control, WC); and water (34.5 C) after hemorrhage (WH) of 14.8 plus or minus 0.3 percent of their blood volume. Blood volume was -11.6 plus or minus 0.6 percent at immersion (time 0). Mean (bar-X hrs 1-5) Q(sub co) was unchanged in WC (5.3 plus or minus 0.01 l/min) and in WH (4.5 plus or minus 0.1 l/min), but decreased (P less than 0.05) in DC to 3.6 plus or minus 0.1 l/min. Mean urine excretion rates were 1.0 plus or minus 0.2 ml/min for DC and 1.1 plus or minus 0.2 ml/min for WH; both were lower (P less than 0.05) than that for WC of 2.0 plus or minus 0.4 ml/min. Plasma (Na+) and (Osm) were unchanged in all experiments. Mean plasma vasopressin (PVP) (bar-X hrs 1-5) was 1.1 plus or minus 0.1 pg/ml in WC, and higher (P less than 0.05) in DC (2.1 plus or minus 0.2 pg/ml)and WH (2.1 plus or minus 0.1 pg/ml); it was unchanged during air and water test periods. Thus, hemorrhage attenuated the immersion-induced increase in Q(sub co), eliminated the WC diuresis, maintained plasma renin activity and PVP at DC levels and did not change immersion-induced aldosterone suppression; the osmotic diuresis during control immersion is apparently not due to either aldosterone suppression or vasopressin suppression.

  5. Alpha-adrenoceptor antagonists and chemical sympathectomy exacerbate anaphylaxis-induced hypotension, but not portal hypertension, in anesthetized rats.

    PubMed

    Wang, Mofei; Tanida, Mamoru; Shibamoto, Toshishige; Kurata, Yasutaka

    2013-10-15

    Anaphylactic shock is sometimes life-threatening, and it is accompanied by hepatic venoconstriction in animals, which, in part, accounts for anaphylactic hypotension. Roles of norepinephrine and α-adrenoceptor in anaphylaxis-induced hypotension and portal hypertension were investigated in anesthetized ovalbumin-sensitized Sprague-Dawley rats. The sensitized rats were randomly allocated to the following pretreatment groups (n = 6/group): 1) control (nonpretreatment), 2) α1-adrenoceptor antagonist prazosin, 3) nonselective α-adrenoceptor antagonist phentolamine, 4) 6-hydroxydopamine-induced chemical sympathectomy, and 5) surgical hepatic sympathectomy. Anaphylactic shock was induced by an intravenous injection of the antigen. The systemic arterial pressure (SAP), central venous pressure (CVP), portal venous pressure (PVP), and portal venous blood flow (PBF) were measured, and splanchnic [Rspl: (SAP-PVP)/PBF] and portal venous [Rpv: (PVP-CVP)/PBF] resistances were determined. Separately, we measured efferent hepatic sympathetic nerve activity during anaphylaxis. In the control group, SAP markedly decreased, followed by a gradual recovery toward baseline. PVP and Rpv increased 3.2- and 23.3-fold, respectively, after antigen. Rspl decreased immediately, but only transiently, after antigen, and then increased 1.5-fold later than 10 min. The α-adrenoceptor antagonist pretreatment or chemical sympathectomy inhibited the late increase in Rspl and the SAP recovery. Pretreatment with α-adrenoceptor antagonists, or either chemical or surgical hepatic sympathectomy, did not affect the antigen-induced increase in Rpv. Hepatic sympathetic nerve activity did not significantly change after antigen. In conclusion, α-adrenoceptor antagonists and chemical sympathectomy exacerbate anaphylaxis-induced hypotension, but not portal hypertension, in anesthetized rats. Hepatic sympathetic nerves are not involved in anaphylactic portal hypertension.

  6. Neurogenic Hyperadrenergic Orthostatic Hypotension – A Newly-recognized Variant of Orthostatic Hypotension in Older Adults with Elevated Norepinephrine

    PubMed Central

    Mar, Philip L; Shibao, Cyndya A.; Garland, Emily M; Black, Bonnie K; Biaggioni, Italo; Diedrich, André; Paranjape, Sachin Y; Robertson, David; Raj, Satish R

    2015-01-01

    Patients with neurogenic orthostatic hypotension (OH) typically have impaired sympathetic nervous system tone and therefore low levels of upright plasma norepinephrine. We report a subset of patients who clinically have typical neurogenic OH but who paradoxically have elevated upright levels of plasma norepinephrine. We retrospectively studied 83 OH patients evaluated at the Vanderbilt Autonomic Dysfunction Center between August 2007 and May 2013. Based upon standing norepinephrine, patients were dichotomized into a hyperadrenergic orthostatic hypotension group (hyperOH: upright NE ≥3.55 nmol/L [600 pg/mL], n=19) or a non-hyperadrenergic orthostatic hypotension group (nOH: upright NE < 3.55 nmol/L [600 pg/mL], n=64). Medical history and data from autonomic testing, including the Valsalva maneuver (VM), were analyzed. HyperOH patients had profound orthostatic falls in blood pressure, but less severe than in nOH (change in SBP: −53±31 mmHg vs. −68±33 mmHg, P=0.050; change in DBP: −18±23 mmHg vs. −30±17 mmHg, P=0.01). The expected compensatory increase in standing heart rate was similarly blunted in both hyperOH and nOH groups (84±15 bpm vs. 82±14 bpm; P=0.6). HyperOH patients had less severe sympathetic failure as evidenced by smaller falls in DBP during phase 2 of VM, and a shorter VM phase 4 blood pressure recovery time (16.5±8.9 sec vs. 31.6±16.6 sec; P<0.001) than nOH patients. Neurogenic hyperOH patients have severe neurogenic orthostatic hypotension, but have less severe adrenergic dysfunction than nOH patients. Further work is required to understand if hyperOH patients will progress to nOH or if this represents a different disorder. PMID:25706983

  7. [Role of paraventricular nucleus in natriuresis and diuresis induced by volume expansion in rabbits].

    PubMed

    Zhang, B; Lin, M Z; Han, G C

    2000-02-01

    In sham-lesioned and paraventricular nucleus (PVN) lesioned rabbits, the peak increases of urine volume (UV) induced by volume expansion (VE) were 0.59+/-0.09 and 0.31+/-0.03 ml/min (P<0.01) respectively, whereas the peak increases of U(Na)V were respectively 66.76+/-6.74 and 36.05+/-3.44 micromol/min (P<0.01). No significant differences were found in the two increases induced by VE between rabbits with intact and those with sham-lesioned PVN. In rabbits with vagotomy there were no changes in the two increases after PVN lesion (P>0.05). In rabbits with renal denervation there was no significant change in natriuretic response after PVN lesion (P>0.05), but lesion of PVN significantly attenuated diuretic response (P<0.02). There were no significant differences in glomerular filtration rate (GFR) and renal plasma flow (RPF) before or after VE between the rabbits with intact and lesioned PVN (P>0.05). These results suggest that PVN is involved in the regulation of natriuresis and diuresis induced by VE, which are mediated by vagal afferent nerve, whereas the renal sympathetic efferent nerve may be involved in natriuretic response.

  8. The role of atrial natriuretic peptide (ANP) in cold-induced diuresis (CID)

    SciTech Connect

    Agnew, J.W.; Freund, B.J.; DuBose, D.A.; McKay, J.M.; Hashiro, G.M. Tripler Army Medical Center, Honolulu, HI )

    1991-03-11

    The hormonal control of cold-induced diuresis (CID) remains unresolved. This study investigated the role of ANP, plasma vasopressin (AVP), and aldosterone (ALDO) on CID. Four semi-nude men participated in a 210 min exposure to 15C and 29C air, on separate days. These subjects drank 300 mL of water and had an intravenous saline drip throughout both exposures to replace blood and insensible fluid losses. CID was observed in 15C but not in the 29C experiment, as indicated by a greater urine output. In 15C, atrial natriuretic peptide (ANP) increased after 90 min by 41% and remained elevated for 2 h relative to 29C. No differences were observed in AVP between 15C and 29C. In the 15C versus the 29C experiment, ALDO was approximately 37% lower at the pre, 15 and 90 min time periods. Mean arterial blood pressure was generally greater but only significant at 60 min during the 15C versus the 29C experiment. Urinary NA{sup +} excretion was elevated in 15C relative to 29C while no difference in K{sup +} excretion was observed. Although pressure effects may contribute, the observed natriuresis in the absence of a kaliuresis in the cold suggests a physiological role of ANP in CID.

  9. Dominant factors that govern pressure natriuresis in diuresis and antidiuresis: a mathematical model.

    PubMed

    Moss, Robert; Layton, Anita T

    2014-05-01

    We have developed a whole kidney model of the urine concentrating mechanism and renal autoregulation. The model represents the tubuloglomerular feedback (TGF) and myogenic mechanisms, which together affect the resistance of the afferent arteriole and thus glomerular filtration rate. TGF is activated by fluctuations in macula densa [Cl(-)] and the myogefnic mechanism by changes in hydrostatic pressure. The model was used to investigate the relative contributions of medullary blood flow autoregulation and inhibition of transport in the proximal convoluted tubule to pressure natriuresis in both diuresis and antidiuresis. The model predicts that medullary blood flow autoregulation, which only affects the interstitial solute composition in the model, has negligible influence on the rate of NaCl excretion. However, it exerts a significant effect on urine flow, particularly in the antidiuretic kidney. This suggests that interstitial washout has significant implications for the maintenance of hydration status but little direct bearing on salt excretion, and that medullary blood flow may only play a signaling role for stimulating a pressure-natriuresis response. Inhibited reabsorption in the model proximal convoluted tubule is capable of driving pressure natriuresis when the known actions of vasopressin on the collecting duct epithelium are taken into account.

  10. Posterior reversible encephalopathy syndrome in setting of postobstructive diuresis and persistent hypocalcemia.

    PubMed

    Gera, Dinesh N; Patil, Sachin B; Parikh, Mitul; Modi, Pranjal R; Kute, Vivek B; Trivedi, Hargovind L

    2012-01-01

    Posterior reversible encephalopathy syndrome (PRES) is a clinicoradiographic entity of heterogenous etiologies, which are grouped together because of similar findings on neuroimaging studies, associated with similar symptom complex of headache, vision loss, altered mentation, and seizures. In this report, we describe a case of PRES in setting of postobstructive diuresis in a 5-year-old male child, whose solitary functioning kidney was obstructed by a 1.6-cm radio-opaque stone, who after percutaneous nephrostomy (PCN) diversion developed persistent hypocalcemia which persisted despite maximum replacement by iv calcium gluconate drip, and the child developed repeated generalized tonic clonic convulsions and became unconscious for 4 days. Computerized tomography (CT) scan of the brain showed typical hypodensities in bilateral occipitoparietal regions suggesting PRES. Ultimately, over a period of 4 days, his hypocalcemia could be corrected and the child was neurologically normal on the 5th day. CT scan of the brain after a month was free of any hypodensities.

  11. Ultrawide-band electromagnetic pulses induced hypotension in rats.

    PubMed

    Lu, S T; Mathur, S P; Akyel, Y; Lee, J C

    The ultrawide-band (UWB) electromagnetic pulses are used as a new modality in radar technology. Biological effects of extremely high peak E-field, fast rise time, ultrashort pulse width, and ultrawide band have not been investigated heretofore due to the lack of animal exposure facilities. A new biological effects database is needed to establish personnel protection guidelines for these new type of radiofrequency radiation. Functional indices of the cardiovascular system (heart rate, systolic, mean, and diastolic pressures) were selected to represent biological end points that may be susceptible to the UWB radiation. A noninvasive tail-cuff photoelectric sensor sphygmomanometer was used. Male Wistar-Kyoto rats were subjected to sham exposure, 0.5-kHz (93 kV/m, 180 ps rise time, 1.00 ns pulse width, whole-body averaged specific absorption rate, SAR = 70 mW/kg) or a 1-kHz (85 kV/m, 200 ps rise time, 1.03 ns pulse width, SAR = 121 mW/kg) UWB fields in a tapered parallel plate GTEM cell for 6 min. Cardiovascular functions were evaluated from 45 min to 4 weeks after exposures. Significant decrease in arterial blood pressures (hypotension) was found. In contrast, heart rate was not altered by these exposures. The UWB radiation-induced hypotension was a robust, consistent, and persistent effect.

  12. Ultrawide-band electromagnetic pulses induced hypotension in rats.

    PubMed

    Lu, S T; Mathur, S P; Akyel, Y; Lee, J C

    1999-09-01

    The ultrawide-band (UWB) electromagnetic pulses are used as a new modality in radar technology. Biological effects of extremely high peak E-field, fast rise time, ultrashort pulse width, and ultrawide band have not been investigated heretofore due to the lack of animal exposure facilities. A new biological effects database is needed to establish personnel protection guidelines for these new type of radiofrequency radiation. Functional indices of the cardiovascular system (heart rate, systolic, mean, and diastolic pressures) were selected to represent biological end points that may be susceptible to the UWB radiation. A noninvasive tail-cuff photoelectric sensor sphygmomanometer was used. Male Wistar-Kyoto rats were subjected to sham exposure, 0.5-kHz (93 kV/m, 180 ps rise time, 1.00 ns pulse width, whole-body averaged specific absorption rate, SAR = 70 mW/kg) or a 1-kHz (85 kV/m, 200 ps rise time, 1.03 ns pulse width, SAR = 121 mW/kg) UWB fields in a tapered parallel plate GTEM cell for 6 min. Cardiovascular functions were evaluated from 45 min to 4 weeks after exposures. Significant decrease in arterial blood pressures (hypotension) was found. In contrast, heart rate was not altered by these exposures. The UWB radiation-induced hypotension was a robust, consistent, and persistent effect.

  13. [Intermittent focal cerebral ischemia in hypotension due to pacemaker syndrome].

    PubMed

    Hagendorff, A; Pizzulli, L; Dettmers, C; Block, A; Omran, H; Hartmann, A; Manz, M; Lüderitz, B

    1994-12-01

    A pacemaker syndrome manifested as transient sensoric aphasia in a 68-year-old woman with a VVI-pace-maker implanted after SA-block. The attack occurred during long-term blood pressure recording and Holter monitoring. Borderline hypotension was documented during ventricular pacing which induced a retrograde excitation of the atrium. Clinical investigations excluded any intracranial abnormality, any source of embolism or stenosis of extra- and intracranial cerebral arteries. Cerebral blood flow measurements revealed a significant increase during pacing at elevated heart rate. Therefore, a device for AV-sequential pacing was implanted and basic pacing rate was elevated. The present case report indicates that focal and not only global cerebral ischemia can be produced by an impairment of systemic hemodynamics due to hypotension and a pacemaker syndrome. Improvement of cerebral blood flow during pacing is an unexpected finding contrasting with the concept of autoregulation. In addition, pacemaker implantation should be discussed in patients with transient cerebral perfusion deficits if an improvement of cerebral blood flow is documented along with rising heart rate.

  14. Cortical blood flow in controlled hypotension as measured by thermal diffusion 1

    PubMed Central

    Carter, L. Philip; Atkinson, James R.

    1973-01-01

    A thermal diffusion flow probe which gave a continuous, dynamic, quantitative record of cortical blood flow (CBF) was used to assess CBF in experimental animals with controlled hypotension. Acute hypotension was produced by trimethaphan camsylate, halothane, and sodium nitroprusside. Halothane produced less reduction in CBF per drop in blood pressure than the other two agents. Images PMID:4772724

  15. Surgical treatment of cervical disc protrusion causing intracranial hypotension following chiropractic manipulation.

    PubMed

    Wilson, David; Steel, Timothy; Sutton, Ian

    2015-09-01

    We describe a woman with intracranial hypotension provoked by a combination of calcified disc protrusion and chiropractic manipulation who required surgical intervention for definitive treatment. Intracranial hypotension is a rare but increasingly well recognized cause of orthostatic headache that arises due to spinal cerebrospinal fluid leakage from meningeal diverticula or dural perforations.

  16. Marking: A Critical Alternative.

    ERIC Educational Resources Information Center

    Hull, Charles

    1984-01-01

    Having pupils critique their own work is an alternative to marking that is worthy of consideration. Pupil critique fosters in students a willingness to take responsibility for the quality of their work products. (RM)

  17. Ames Fellows Award - Mark

    NASA Video Gallery

    Dr. Hans Mark is a leading expert in the fields of aerospace design and national defense policy. From 1969 to 1977, he served as Director of the NASA Ames Research Center. During his tenure, Ames b...

  18. Mark IVA microprocessor support

    NASA Technical Reports Server (NTRS)

    Burford, A. L.

    1982-01-01

    The requirements and plans for the maintenance support of microprocessor-based controllers in the Deep Space Network Mark IVA System are discussed. Additional new interfaces and 16-bit processors have introduced problems not present in the Mark III System. The need for continuous training of maintenance personnel to maintain a level of expertise consistent with the sophistication of the required tools is also emphasized.

  19. Hypotensive and Angiotensin-Converting Enzyme Inhibitory Activities of Eisenia fetida Extract in Spontaneously Hypertensive Rats

    PubMed Central

    Mao, Shumei; Li, Chengde

    2015-01-01

    Objectives. This study aimed to investigate the antihypertensive effects of an Eisenia fetida extract (EFE) and its possible mechanisms in spontaneously hypertensive rats (SHR rats). Methods. Sixteen-week-old SHR rats and Wistar-Kyoto rats (WKY rats) were used in this study. Rats were, respectively, given EFE (EFE group), captopril (captopril group), or phosphate-buffered saline (PBS) (normal control group and SHR group) for 4 weeks. ACE inhibitory activity of EFE in vitro was determined. The systolic blood pressure (SBP) and diastolic blood pressure (DBP) were measured using a Rat Tail-Cuff Blood Pressure System. Levels of angiotensin II (Ang II), aldosterone (Ald), and 6-keto-prostaglandin F1 alpha (6-keto-PGF1α) in plasma were determined by radioimmunoassay, and serum nitric oxide (NO) concentration was measured by Griess reagent systems. Results. EFE had marked ACE inhibitory activity in vitro (IC50 = 2.5 mg/mL). After the 4-week drug management, SHR rats in EFE group and in captopril group had lower SBP and DBP, lower levels of Ang II and Ald, and higher levels of 6-keto-PGF1α and NO than the SHR rats in SHR group. Conclusion. These results indicate that EFE has hypotensive effects in SHR rats and its effects might be associated with its ACE inhibitory activity. PMID:26798397

  20. Spontaneous intracranial hypotension resulting from a thoracic osteophyte.

    PubMed

    Hung, Ling-Chien; Hsu, Yung-Chu

    2015-06-01

    We report a 34-year-old woman who presented with progressive postural headache and neck tightness over 1week. We confirmed the diagnosis of spontaneous intracranial hypotension (SIH) and spinal images showed a thoracic osteophyte caused the cerebrospinal fluid (CSF) leak. SIH caused by spinal CSF leak is generally thought to be a consequence of deficiency of the spinal meninges in conjunction with trivial trauma. Less commonly, spinal bony pathology can lead to SIH. We reviewed 13 reported patients with bony structural pathology related SIH. After two to three epidural blood patches, eight patients underwent surgery. They generally had good outcomes. In conclusion, even though surgical repair confers specific risks, it should be considered after repetitive failures of epidural blood patches. The long-term prognoses of surgical versus non-surgical patients warrants further investigation.

  1. Neurogenic orthostatic hypotension – management update and role of droxidopa

    PubMed Central

    Vijayan, Joy; Sharma, Vijay K

    2015-01-01

    Orthostatic hypotension (OH) is defined as a significant decrease in blood pressure (BP) during the first 3 minutes of standing or a head up on a tilt table. Symptoms of OH are highly variable, ranging from mild light-headedness to recurrent syncope. OH occurs due to dysfunction of one or more components of various complex mechanisms that interplay closely to maintain BP in a normal range during various physiological and associated disease states. Various biochemical and electrophysiological studies are often undertaken to assess the severity and etiology of OH. In addition to the lifestyle modifications, various medications that stimulate the adrenergic receptors or increase central blood volume are used in patients with OH. Droxidopa is a newer agent that increases the levels of norepinephrine in postganglionic sympathetic neurons. Management strategies for OH are presented, including the mechanism of action of droxidopa and various studies performed to assess its efficacy. PMID:26089676

  2. Early metabolic effects of hypotension on rat kidney.

    PubMed

    Freeman, D M; Chan, L; Yahaya, H; Holloway, P; Ross, B D

    1989-01-01

    Saturation-transfer phosphorus nuclear magnetic resonance (STNMR) has been applied to the rat kidney in vivo. The rate of renal metabolism determined by this method compares favorably with the renal oxygen consumption, assuming an ATP:oxygen ratio of 2. Hemorrhagic hypotension resulted in a 20% fall in renal blood flow and a significant fall in oxygen consumption. The rate of renal metabolism fell by 50%. This rate of ATP synthesis was below that required to maintain a normal [ATP], but renal [Pi] was not increased. When renal perfusion was reduced by 60%, intrarenal [Pi] rose. When [P1] was elevated, the method os STNMR no longer gave a reliable measure of the rate ATP synthesis, indicating that this new Pi pool was not in rapid chemical exchange with ATP. STNMR represents a useful noninvasive means of monitoring renal metabolic rate, with limitations due to insensitivity and the existence of multiple pools of intrarenal Pi.

  3. Pathophysiology and management of spontaneous intracranial hypotension--a review.

    PubMed

    Syed, Nadir Ali; Mirza, Farhan Arshad; Pabaney, Aqueel Hussain; Rameez-ul-Hassan

    2012-01-01

    Spontaneous Intracranial Hypotension is a syndrome involving reduced intracranial pressure secondary to a dural tear which occurs mostly due to connective tissue disorders such as Marfans Syndrome, and Ehler Danlos Syndrome. Patients with dural ectasias leading to CSF leakage into the subdural or epidural space classically present with orthostatic headaches and cranial nerve deficits mostly seen in cranial nerves V-VIII. Diagnosis of SIH is confirmed with the aid of neuroimaging modalities of which Cranial MR imaging is most widely used. SIH can be treated conservatively or with epidural blood patches which are now widely being used to repair dural tears, and their effectiveness is being recognized. Recently epidural injection of fibrin glue has also been used which has been found to be effective in certain patients.

  4. Effects of propranolol in a case of orthostatic hypotension.

    PubMed Central

    Brevetti, G; Chiariello, M; Lavecchia, G; Rengo, F

    1979-01-01

    In a hypertensive patient with orthostatic hypotension, the changes in several haemodynamic indices with respect to posture were evaluated. In the upright position, systemic blood pressure was reduced as compared with the supine position, and peripheral vasodilation was present, as shown by an increase in Jantsch's index of the impedance plethysmographic tracings. Systolic time intervals remained unchanged with changes in posture. Propranolol 10 mg intravenously brought the response to normal. In fact, after beta-blockade in the standing position the blood pressure remained unchanged and normal peripheral vasoconstriction was observed. Similar results were seen during atrial pacing at a constant heart rate of 130 beats/minute. In this patient, propranolol appears to normalise the response to the posture change, by restoring normal vasoconstriction in the upright position. PMID:426969

  5. Ibuprofen Can Induce Syndrome of Inappropriate Diuresis in Healthy Young Patients

    PubMed Central

    Roche, Céline; Ragot, Céline; Moalic, Jean-Luc; Simon, Fabrice; Oliver, Manuela

    2013-01-01

    A 30-year-old caucasian woman, without past medical history or known drug use, was admitted to the emergency department for persistent fever and arthralgias. The laboratory analysis showed moderate hypoosmolar hyponatremia (Na: 132 mmol/L, osmolality: 239 mOsm/L), normal sodium excretion (<20 mmol/L), and a high urinary osmolality (415 mOsm/L). Later, she deteriorated with seizures and deeper hyponatremia (Na: 113 mmol/L) and so was moved to the critical care unit. At first, no obvious aetiology was found, the patient was euvolemic, as she was well hydrated and lacked concerning findings of heart failure, renal disease, or liver cirrhosis. A syndrome of inappropriate diuresis (SIAD) was proposed, and corrective measures were started immediately to reduce her hyponatremia, including restriction of fluid intake. The administration of intravenous hypertonic saline solution permitted normal neurological status to be restored and corrected the sodium concentration but induced reversible acute renal failure. Further investigation revealed that the patient had ingested 8 g ibuprofen two days before admission. After other aetiologies were ruled out, drug-induced SIAD due to ibuprofen was the most likely diagnosis for this patient. SIAD-associated hyponatremia and acute renal failure are rare side effects of nonsteroidal anti-inflammatory drugs, particularly in young people. Therefore, this case may represent a unique case of NSAID-induced SIAD and highlight the need to obtain thorough medication histories and exclude all other potential causes in hyponatremic patients. PMID:23840216

  6. Pharmacognosy and hypotensive evaluation of Ficus exasperata Vahl (Moraceae) leaf.

    PubMed

    Ayinde, Buniyamin A; Omogbai, Eric K I; Amaechina, Fabian C

    2007-01-01

    There is already a literature report on the anti-ulcer effect of water extract of Ficus exasperata. Some communities in Edo and Delta States of Nigeria use the decoction of the leaf as hypotensive crude drug. Verification of this claim and also the microscopy and other pharmacognostic parameters which can be used to establish the identity of the leaf were carried out. The microscopy of the leaf powder revealed the presence of straight walled epidermal cells, cone or nail shaped trichomes or epidermal hairs, clustered or prismatic calcium oxalate crystals of varying dimensions. The percentage weight loss on drying was 9.84 +/- 0.08 whereas water and alcohol extractive values were 5.29 +/- 0.07 and 2.21 +/- 0.11, respectively. The ash value was 30.68 +/- 0.44 whereas the acid insoluble ash and water soluble ash values were 17.87 +/- 0.37 and 16.73 +/- 0.13, respectively. Preliminary phytochemistry of leaf showed that it contains tannins, flavonoids and saponins with no traces of alkaloids or anthraquinones. The water extract showed a dose related reduction in mean arterial blood pressure. At 10 mg/kg, a reduction of 16.6 +/- 1.1 mmHg was observed, whereas at 30 mg/kg, a fall in mean arterial pressure of 38.3 +/- 0.6 mmHg was obtained. The hypotensive effect of the extract was significantly reduced with a prior administration of 2.5 mg of either atropine or chlorpheniramine. This suggests the probable stimulation of muscarinic receptors in the heart or release of histamine into the circulatory system thereby causing the initial fall in blood pressure.

  7. Noise-induced compensation for postural hypotension in primary autonomic failure.

    PubMed

    Yamamoto, Yoshiharu; Hidaka, Ichiro; Iso-o, Noriko; Komai, Akira; Soma, Rika; Kwak, Shin

    2002-07-26

    Noise can have a beneficial effect on sensory neurological systems, enhancing detection of small afferent signals and thereby improve efferent neural responses. We hypothesized whether a similar mechanism would facilitate impaired neural transmission associated with neurological disease, and tested whether addition of external noise to baroreceptor signaling could improve blunted autonomic efferent responses to a postural challenge in patients with primary autonomic failure (PAF). Five PAF patients were tested, one in duplicate and another triplicate, for their transient responses of heart rate (measured from electrocardiographic RR intervals; RRIs) and systolic (SBP) and diastolic (DBP) blood pressures to either 30 degrees or 60 degrees head-up tilt, with and without continuous application of beat-to-beat Gaussian white noise to the carotid sinus baroreceptors. Also, the effects of noise were compared with those by a continuous positive pressure applied to the carotid sinus baroreceptors. The data were fit to a first order model to evaluate the speed (by the time constant; tau) and the magnitudes (by the steady state gains; Gs) of RRI and blood pressure responses. The PAF patients exhibited marked drops in SBP and DBP and a blunted increase in heart rate upon transition from a supine to a head-up position. Addition of noise, not the continuous positive pressure, to the arterial baroreceptors significantly (P<0.05) increased the G in RRI and diminished the Gs in SBP and DBP, though the time courses (taus) of both the RRI and blood pressure responses were unaffected. The addition of external noise to baroreceptor signaling ameliorated the marked postural hypotension seen in patients with PAF.

  8. Meetings with Mark Vishik

    NASA Astrophysics Data System (ADS)

    Kalikinskaya, E. I.

    2014-12-01

    Mark Iosifovich Vishik was my husband Vladimir Chepyzhov's advisor during his years as a student in the Faculty of Mechanics and Mathematics at Moscow State University, and afterwards they worked together for almost 30 years. This is why I knew him personally while not being a mathematician myself: we sometimes talked on the phone, and met during common trips and a few holidays. In his last years, after the death of his devoted wife who was also his best friend, my husband and I decided to visit Mark regularly in order to comfort him in his loneliness, and many other of his friends did the same. I can say without exaggeration that Mark loved to talk with me about everyday matters, to reminisce about his wife Asya Moiseevna, their friends and relatives, to tell stories of his youth and the wonderful encounters that had so enriched his life. We had the idea to write down our conversations and publish them as a book. Unfortunately, few such conversations lay ahead. The last one took place in January 2010. We did not write a book, but we did write an article [1], which was published in English in the form of an interview with Mark. The present article is based on our conversations with Mark. Here I will try to recount his memories about people who played an important role in his life.

  9. Aircraft vortex marking program

    NASA Technical Reports Server (NTRS)

    Pompa, M. F.

    1979-01-01

    A simple, reliable device for identifying atmospheric vortices, principally as generated by in-flight aircraft and with emphasis on the use of nonpolluting aerosols for marking by injection into such vortex (-ices) is presented. The refractive index and droplet size were determined from an analysis of aerosol optical and transport properties as the most significant parameters in effecting vortex optimum light scattering (for visual sighting) and visual persistency of at least 300 sec. The analysis also showed that a steam-ejected tetraethylene glycol aerosol with droplet size near 1 micron and refractive index of approximately 1.45 could be a promising candidate for vortex marking. A marking aerosol was successfully generated with the steam-tetraethylene glycol mixture from breadboard system hardware. A compact 25 lb/f thrust (nominal) H2O2 rocket chamber was the key component of the system which produced the required steam by catalytic decomposition of the supplied H2O2.

  10. The PCB mark

    SciTech Connect

    1994-12-01

    Polychlorinated biphenyls (PCBs) are a class of organic chemicals that had become widely used in industrial applications due to their practical physical and chemical properties. Historical uses of PCBs include dielectric fluids (used in utility transformers, capacitors, etc.), hydraulic fluids, and other applications requiring stable, fire-retardant materials. Due to findings that PCBs may cause adverse health effects and due to their persistence and accumulation in the environment. The Toxic Substances Control Act (TSCA), enacted on October 11, 1976, banned the manufacture of PCBs after 1978 [Section 6(e)]. The first PCB regulations, promulgated at 40 CFR Part 761, were finalized on February 17, 1978. These PCB regulations include requirements specifying disposal methods and marking (labeling) procedures, and controlling PCB use. To assist the Department of Energy (DOE) in its efforts to comply with the TSCA statute and implementing regulations, the Office of Environmental Guidance has prepared the document ``Guidance on the Management of Polychlorinated Biphenyls (PCBs).`` That document explains the requirements specified in the statute and regulations for managing PCBs including PCB use, storage, transport, and disposal. The requirements outlined at 40 CFR 761.40 through 761.45 specify marking requirements for most PCB items (i.e., any PCB Article, PCB Container, PCB Article Container, or PCB Equipment that contains PCBs). Most PCB items require PCB marks, which are defined as a descriptive name, instructions, cautions, or other information applied to PCB Items or other objects subject to these regulations. The marking regulations include requirements for PCB marks on PCB Items, storage areas, and temporary storage areas. This Information Brief supplements the PCB guidance document by responding to common questions concerning marking requirements for PCBs. It is one of a series of Information Briefs pertinent to PCB management issues.

  11. Hypotensive Response Magnitude and Duration in Hypertensives: Continuous and Interval Exercise

    PubMed Central

    de Carvalho, Raphael Santos Teodoro; Pires, Cássio Mascarenhas Robert; Junqueira, Gustavo Cardoso; Freitas, Dayana; Marchi-Alves, Leila Maria

    2015-01-01

    Background Although exercise training is known to promote post-exercise hypotension, there is currently no consistent argument about the effects of manipulating its various components (intensity, duration, rest periods, types of exercise, training methods) on the magnitude and duration of hypotensive response. Objective To compare the effect of continuous and interval exercises on hypotensive response magnitude and duration in hypertensive patients by using ambulatory blood pressure monitoring (ABPM). Methods The sample consisted of 20 elderly hypertensives. Each participant underwent three ABPM sessions: one control ABPM, without exercise; one ABPM after continuous exercise; and one ABPM after interval exercise. Systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), heart rate (HR) and double product (DP) were monitored to check post-exercise hypotension and for comparison between each ABPM. Results ABPM after continuous exercise and after interval exercise showed post-exercise hypotension and a significant reduction (p < 0.05) in SBP, DBP, MAP and DP for 20 hours as compared with control ABPM. Comparing ABPM after continuous and ABPM after interval exercise, a significant reduction (p < 0.05) in SBP, DBP, MAP and DP was observed in the latter. Conclusion Continuous and interval exercise trainings promote post-exercise hypotension with reduction in SBP, DBP, MAP and DP in the 20 hours following exercise. Interval exercise training causes greater post-exercise hypotension and lower cardiovascular overload as compared with continuous exercise. PMID:25517389

  12. Orthostatic hypotension, non-dipping and striatal dopamine in Parkinson disease.

    PubMed

    Oh, Yoon-Sang; Kim, Joong-Seok; Chung, Yong-An; You, Ie Ryung; Yang, Dong-Won; Chung, Sung-Woo; Park, Jeong-Wook; Kim, Yeong-In; Lee, Kwang-Soo

    2013-04-01

    Orthostatic hypotension and non-dipping are relatively common autonomic dysfunctions in patients with Parkinson disease (PD). These abnormalities have been thought to occur independently of striatal dopaminergic depletion; however, only little preliminary information is available. In this study, we investigated the association of neurocirculatory changes with striatal dopamine transporter status in 69 patients with early PD. Seventeen patients had orthostatic hypotension and 55 patients were non-dippers. A comparison between cases with and without orthostatic hypotension was insignificant for striatal dopamine transporter uptake. These insignificances continued in a comparison of dippers and non-dippers. These results suggest that sympathetic noradrenergic dysfunctions in PD are independent of striatal dopamine transporter depletion.

  13. [Prophylaxis and treatment of arterial hypotension during caesarean with spinal anaesthesia].

    PubMed

    Arias, J; Lacassie, H J

    2013-11-01

    Caesarean section is one of the most common surgical procedures worldwide. Arterial hypotension is the most prevalent adverse effect after spinal anaesthesia. Various methods have been used to prevent or treat hypotension. Since there is no treatment 100% effective by itself, a multimodal management is required to achieve an optimum balance and avoidance of hemodynamic imbalance. Strategies to avoid this side effect are analyzed on the basis of the best evidence available so far, summarized as mechanical factors, anesthetics, fluids and vasopressors. After spinal anaesthesia for caesarean section, the best strategy available for prevention of hypotension appears to be the combination of crystalloids along with an alpha 1 agonist vasopressor.

  14. Teaching with Mark Dion

    ERIC Educational Resources Information Center

    Fusaro, Joe

    2011-01-01

    Mark Dion creates sculptures, installations, and interactive environments that sometimes seem contrary to what one expects from visual artists. Remarkable curiosity cabinets and carefully arranged artifacts from specific places and time periods make up a large part of his work. His work does not neatly fit into traditional lessons about elements…

  15. Fathoming Mark Twain.

    ERIC Educational Resources Information Center

    Biggar, Joanna

    1988-01-01

    Relates the efforts of completing two collections of the works and papers of Mark Twain. Describes the combined efforts of the University of Iowa and the University of California to publish both a scholarly edition and a reader's edition devoted to Twain. (KO)

  16. Airbag bounce marks

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Looking east from the lander, the last few bounce marks as Pathfinder rolled to a stop on July 4 are visible in the soil in this image, taken by the Imager for Mars Pathfinder (IMP). The two most distant marks, identified by pointers in the image, consist of dark patches of disturbed soil. The three closest marks are clearly visible in the foreground, with one easily identifiable behind the Atmospheric Structure Instrument/Meteorology Package (ASI/MET) mast, is at right. The most distant positively identified bounce mark, indicated by the pointer at right, is approximately 11.3 meters (37 feet) from the lander.

    Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator. JPL is an operating division of the California Institute of Technology (Caltech).

  17. Little Jiffy, Mark IV

    ERIC Educational Resources Information Center

    Kaiser, Henry F.; Rice, John

    1974-01-01

    In this paper three changes and one new development for the method of exploratory factor analysis (a second generation Little Jiffy) developed by Kaiser are described. Following this short description a step-by-step computer algorithm of the revised method, dubbed Little Jiffy, Mark IV is presented. (MP)

  18. Rehab Mark. Participant's Workbook.

    ERIC Educational Resources Information Center

    Greenwood, Reed; And Others

    This manual is the employer-focused component workbook of a vocational rehabilitation program. Goals of the RehabMark approach include increased exposure of the rehabilitation agency in the local community, expanded contributions by the agency to community members, and services benefiting numerous clients simultaneously. The first half of the…

  19. Interview with Mark Ashwill

    ERIC Educational Resources Information Center

    Landsberger, Joe

    2006-01-01

    This article presents an interview with Mark Ashwill, Director of the Institute of International Education-Vietnam in Ha Noi, Vietnam, a branch of the Institute of International Education (IIE). In this interview, Ashwill talks about his work as Director of the Institute of International Education-Vietnam, the role that communications technology…

  20. Potential involvement of P2Y2 receptor in diuresis of postobstructive uropathy in rats.

    PubMed

    Zhang, Yue; Kohan, Donald E; Nelson, Raoul D; Carlson, Noel G; Kishore, Bellamkonda K

    2010-03-01

    AVP resistance of the medullary collecting duct (mCD) in postobstructive uropathy (POU) has been attributed to increased production of PGE2. P2Y2 receptor activation causes production of PGE2 by the mCD. We hypothesize that increased P2Y2 receptor expression and/or activity may contribute to the diuresis of POU. Sprague-Dawley rats were subjected to bilateral ureteral obstruction for 24 h followed by release (BUO/R, n = 17) or sham operation (SHM/O, n = 15) and euthanized after 1 wk or 12 days. BUO/R rats developed significant polydipsia, polyuria, urinary concentration defect, and increased urinary PGE2 and decreased aquaporin-2 protein abundance in the inner medulla compared with SHM/O rats. After BUO/R, the relative mRNA expression of P2Y2 and P2Y6 receptors was increased by 2.7- and 4.9-fold, respectively, without significant changes in mRNA expression of P2Y1 or P2Y4 receptor. This was associated with a significant 3.5-fold higher protein abundance of the P2Y2 receptor in BUO/R than SHM/O rats. When freshly isolated mCD fractions were challenged with different types of nucleotides (ATPgammaS, ADP, UTP, or UDP), BUO/R and SHM/O rats responded to only ATPgammaS and UTP and released PGE2, consistent with involvement of the P2Y2, but not P2Y6, receptor. ATPgammaS- or UTP-stimulated increases in PGE2 were much higher in BUO/R (3.20- and 2.28-fold, respectively, vs. vehicle controls) than SHM/O (1.68- and 1.30-fold, respectively, vs. vehicle controls) rats. In addition, there were significant 2.4- and 2.1-fold increases in relative mRNA expression of prostanoid EP1 and EP3 receptors, respectively, in the inner medulla of BUO/R vs. SHM/O rats. Taken together, these data suggest that increased production of PGE2 by the mCD in POU may be due to increased expression and activity of the P2Y2 receptor. Increased mRNA expression of EP1 and EP3 receptors in POU may also help accentuate PGE2-induced signaling in the mCD.

  1. Graded Compression Stockings Prevent Post-spaceflight Orthostatic Hypotension

    NASA Technical Reports Server (NTRS)

    Platts, S. H.; Brown, A. K.; Locke, J.; Stenger, M. B.

    2008-01-01

    Post-spaceflight orthostatic intolerance is characterized by hypotension and presyncope in 20-30% of returning astronauts. Previous data from our laboratory suggests that this is largely a result of decreased venous return. Currently, NASA astronauts wear an anti-gravity suit (AGS) which consists of inflatable air bladders over the calves, thighs and abdomen, which are typically pressurized from 0.5 to 1.5 PSI (27 to 78 mmHg). ISS crew members sometimes wear Russian Kentavr suits which consist of laced compression shorts and gaiters, providing 30 mmHg nominally. While these garments are effective during reentry, there are a number of drawbacks that make them impractical for postflight use. We studied the ability of commercially available, custom fit, graded compression stockings (Jobst, 55 mmHg at ankle to 6 mmHg at top of thigh, 25 mmHg mean compression) to prevent postflight orthostatic intolerance, hypothesizing that these garments would prevent orthostatic intolerance following short duration space flight. Crew members from a single Space Shuttle flight were tilted to 80 degrees for 10 min while wearing the stockings (n=5 males) upon arrival at the clinic (2 hrs after landing). Hemodynamic data were compared to data from all crewmembers tilted (without countermeasures) since return to flight (n=9). Two-way, repeated measures ANOVA, using the entire tilt time curve (0-10 min) show that systolic blood pressure (SBP, group effect p=0.008), stroke volume (SV, group effect p=0.003), and cardiac output (CO, group effect p=0.004) were higher in crewmembers who wore the Jobst stockings. A one-way ANOVA comparing the last minute standing also showed that SV (p=0.001) and CO (p less than 0.001) were higher and SBP tended to be higher (p=0.06) in Jobst subjects compared to controls. Control subjects had a higher rate of presyncope than Jobst subjects (3/9 vs 0/5) during the tilt on landing day. Orthostatic hypotension continues to present following spaceflight, despite

  2. Involvement of the renal kallikrein-kinin system in K(+)-induced diuresis and natriuresis in anesthetized rats.

    PubMed

    Suzuki, T; Katori, M; Fujita, T; Kumagai, Y; Majima, M

    2000-07-07

    Intravenous infusion of a high-K(+) solution (67.5 mM KCl, 67.5 mM NaCl) to anesthetized rats increased urine volume by 47.6% after 60 min, compared with infusion of a Na(+) solution (135 mM NaCl). This treatment also increased urinary excretion of Na(+) by 32.2%, in parallel with an increase in excretion of K(+) or Cl(-). Urinary excretion of kallikrein increased within 60 min after the start of K(+) infusion. A bradykinin B(2) receptor antagonist, 8-[3-[N-[(E)-3-(6-acetamidopyridin-3-yl)acryloylglycyl]-N-me thylamino ]-2,6-dichlorobenzyloxy]-2-methylquinoline (FR173657; 1.0 mg/kg, i.v. ), inhibited the K(+)-induced diuresis and natriuresis by 41.0% and 26.7%, respectively. These results indicate that K(+) load induces diuresis and natriuresis through the renal kallikrein-kinin system in rats.

  3. Mark Twain on phrenology.

    PubMed

    Stone, James L

    2003-12-01

    Mark Twain was a noted 19th century American writer and humorist. He often elaborated upon the personalities of his characters, and his observational skills reflected a strong interest in psychology. Similarly, he found an interest in phrenology, a pseudoscience that purported to characterize personality traits according to elevations or depressions on the head. Twain's style is clearly reflected in the interesting essay he wrote regarding his personal experience with phrenology.

  4. Exercise training hypotension - Implications for plasma volume, renin, and vasopressin

    NASA Technical Reports Server (NTRS)

    Greenleaf, J. E.; Sciaraffa, D.; Shvartz, E.; Keil, L. C.; Brock, P. J.

    1981-01-01

    The relation of changes in plasma volume, plasma renin activity and arginine vasopressin to changes in resting blood pressure during exercise training is investigated. Resting supine, sitting, and standing systolic and fifth-phase diastolic blood pressures were measured in ten men before and after an eight-day training period on a cycle ergometer in either a hot (39.8 C) or cool (23.8 C) environment, and compared with plasma volume, renin and vasopressin levels, heart rates, maximal oxygen uptakes, rectal temperatures and sweat rates. Following acclimatization, resting supine and sitting diastolic pressures are observed to decrease by 6 and 9 mm Hg, respectively, while no significant changes are found in the diastolic pressures of the control group or the systolic pressures of either group. Resting plasma volume is found to increase by 12.2% in the controls and by 17.6% after acclimatization following the exercise training. Results suggest that the resting hypotension produced is not attributable to changes in resting plasma volume, renin or vasopressin, although heat acclimatization, which leads to large decreases in plasma volume and increases in vasopressin and renin activity, may be useful in the treatment of hypertension.

  5. Spontaneous Intracranial Hypotension Presenting as a "Pseudo-Chiari 1

    PubMed Central

    Haider, Ali S; Sulhan, Suraj; Watson, Ian T; Leonard, Dean; Arrey, Eliel N; Nguyen, Phu; Layton, Kennith F

    2017-01-01

    Spontaneous intracranial hypotension (SIH) is classified as a decrease in cerebrospinal fluid (CSF) pressure secondary to a CSF leakage and consequent descent of the brain into the foramen magnum. Diagnosing SIH can be difficult due to its overlapping findings with Arnold-Chiari type 1 Malformation (CM1) where the cerebellar tonsils herniate into the foramen magnum. The similarity of both conditions calls for a more reliable imaging technique to localize the CSF leak which could narrow the differential diagnosis and aid in choosing the correct treatment. Here, we present a case of a 28-year-old female, ten weeks post-partum with symptoms similar to SIH. MRI of the brain was remarkable for tonsillar herniation below the foramen magnum. Literature was reviewed for additional neuroradiology techniques that would aid in narrowing our differential diagnosis. Interestingly, computed tomography-, digital subtraction-, and magnetic resonance myelography with intrathecal gadolinium are the preferred techniques for diagnosis of high flow and low flow CSF leaks, respectively. These modalities further aid in choosing the correct treatment while avoiding complications. Literature suggests that treatment for CM1 involves posterior fossa decompression, whereas the mainstay of treatment for SIH involves an epidural blood patch (EBP). Thus, our patient was treated with an EBP and recovered without complication. PMID:28357166

  6. Recent advances in orthostatic hypotension presenting orthostatic dizziness or vertigo.

    PubMed

    Kim, Hyun-Ah; Yi, Hyon-Ah; Lee, Hyung

    2015-11-01

    Orthostatic hypotension (OH), a proxy for sympathetic adrenergic failure, is the most incapacitating sign of autonomic failure. Orthostatic dizziness (OD) is known to be the most common symptom of OH. However, recent studies have demonstrated that 30-39 % of patients with OH experienced rotatory vertigo during upright posture (i.e., orthostatic vertigo, OV), which challenges the dogma that OH induces dizziness and not vertigo. A recent population-based study on spontaneously occurring OD across a wide age range showed that the one-year and lifetime prevalence of OD was 10.9 and 12.5 %, respectively. Approximately 83 % of patients with OD had at least one abnormal autonomic function test result. So far, 11 subtypes of OD have been proposed according to the pattern of autonomic dysfunction, and generalized autonomic failure of sympathetic adrenergic and parasympathetic cardiovagal functions was the most common type. Four different patterns of OH, such as classic, delayed, early, and transient type have been found in patients with OD. The head-up tilt test and Valsalva maneuver should be performed for a comprehensive evaluation of sympathetic adrenergic failure in patients with OD/OV. This review summarizes current advances in OH presenting OD/OV, with a particular focus on the autonomic dysfunction associated with OD.

  7. Hypotension and reduced catecholamines in neuropeptide Y transgenic rats.

    PubMed

    Michalkiewicz, Mieczyslaw; Knestaut, Kriss M; Bytchkova, Elena Yu; Michalkiewicz, Teresa

    2003-05-01

    The neurons that control blood pressure express neuropeptide Y. Administered centrally, this neuropeptide reduces blood pressure and anxiety, together with lowering sympathetic outflow. The generation of neuropeptide Y transgenic rats overexpressing this peptide, under its natural promoter, has allowed us to examine the role of endogenous neuropeptide Y in the long-term control of blood pressure by the sympathetic nervous system. This study tested a hypothesis that endogenous neuropeptide Y acts to reduce blood pressure and catecholamine release. Blood pressure was measured by radiotelemetry in conscious male transgenic and nontransgenic littermates (control). Novel cage with cold water and forced swimming were used as stressors. Catecholamines were determined in 24-hour urine (baseline) and plasma (cold water stress) by a radioenzymatic assay. Blood pressures in baseline and during the stresses were significantly reduced in the transgenic rats. The lower blood pressure was associated with reduced catecholamines, lower decrease in pressure after autonomic ganglionic blockade, and increased longevity. Data obtained through the use of this transgenic rat model support and extend the evidence for the previously postulated sympatholytic and hypotensive effects of neuropeptide Y and provide novel evidence for an important physiological role of endogenous peptide in blood pressure regulation. As indicated by the increased longevity of these rats, in long-term regulation, these buffering actions of neuropeptide Y may have important cardiovascular protective effects against sympathetic hyperexcitation.

  8. Orthostatic hypotension and subjective sleep quality in older people.

    PubMed

    McHugh, Joanna E; Fan, Chie W; Kenny, Rose Ann; Lawlor, Brian A

    2012-01-01

    Poor sleep quality and orthostatic hypotension are common complaints in an older population, and both are related to factors such as polypharmacy and depression. However, it is not known whether there is a direct association between the two. Our objective is to investigate a potential association between orthostatic blood pressure response and subjective sleep quality in older people. A within-subjects, cross-sectional design embedded in a larger longitudinal study design. Participants were recruited from the community to visit the TRIL clinic at St James's Hospital, where they underwent a structured medical and psychosocial assessment. A total of 505 community dwelling adults aged 60+ (321 females, mean age 72.44) were participated in this study. Orthostatic blood pressure responses were recorded during an active stand using Finometer equipment, and health-related factors such as pain ratings, co-morbidities, polypharmacy, timed up and go, Mini-Mental State Examination score, body mass index, as well as depression, anxiety, age and gender, were also recorded. Self-reported sleep quality was also assessed using the Pittsburgh Sleep Quality Index. The results showed that timed up and go, polypharmacy, depression, anxiety, gender and delayed recovery of blood pressure at orthostasis were associated with subjective poor sleep quality. There is an association between subjective sleep quality and delayed recovery of blood pressure at orthostasis, independent of mental health or polypharmacy effects, in older adults. This link may have implications for the management of sleep disorders in older people.

  9. A retrospective study to correlate breech presentation and enhanced risk of postspinal hypotension during cesarean delivery

    PubMed Central

    Jain, Anshul; Pandey, Shivali; Kumar, Roopesh; Sethi, Chavi; Sharma, Sanjya

    2015-01-01

    Background Subarachnoid blockade for cesarean section still poses a threat of profound hypotension and can result in unstable maternal and fetal hemodynamics. The correlation of fetal breech and vertex presentation with the occurrence of hypotension under spinal anesthesia is reviewed in this retrospective, double-blind study. Patients and methods The study was conducted on pregnant females scheduled for a lower segment cesarean section between January 2014 and December 2014. After applying inclusion criteria, 568 patients were recruited in the study out of which 363 had vertex and 184 patients had breech presentation. They were divided into two groups, Group I and Group II. The monitoring and therapeutic data (blood pressure, heart rate, arterial oxygen saturation, and dose of vasopressor/atropine) recovered from automated data analysis were analyzed retrospectively for prevalence of hypotension, bradycardia, and hypotension with bradycardia and nausea ± vomiting. Results Among Group I, prevalence of hypotension, bradycardia, and hypotension together with bradycardia was 152 (41.83%) patients, eight (2.20%) patients, and seven (1.92%) patients, respectively. In Group II, the prevalence of hypotension, bradycardia, and hypotension with bradycardia was 93 (50.5%) patients, five (2.71%) patients, and six (3.2%) patients, respectively. The difference between the two groups was statistically significant for hypotension. For Group I, 152 patients (41.87%) experienced one, 23 patients (6.33%) experienced two, and three patients (0.82%) experienced three episodes of hypotension. In Group II, 93 (50.5%), 19 (7.89%), and two (1.08%) patients experienced such episodes. The difference was significant with respect of one and two episodes. The prevalence of intraoperative nausea was 11.01% (40 patients) in Group I, whereas 11.41% (21 patients) in Group II. Intraoperative vomiting occurred in 19 patients (5.23%) of Group I and 14 patients (7.60%) of Group II. The height of the

  10. Progressively invalidating orthostatic hypotension: A common symptom for a challenging diagnosis

    PubMed Central

    Pelusi, Serena; Lombardi, Rosa; Airaghi, Lorena; Burdick, Larry; Rango, Mario; Penatti, Alessandra; Fargion, Silvia

    2016-01-01

    We discuss here an uncommon condition of neurogenic hypotension in the context of immunoglobulin light chain (amyloid light-chain) amyloidosis. The most serious feature was autonomic nervous system impairment, mainly characterized by severe refractory orthostatic hypotension, which became progressively invalidating, forcing the patient to bed. Moreover, since the systemic involvement of the disease, the patient presented also diarrhea, dysphagia, asthenia, peripheral edema because of gastrointestinal, and kidney dysfunction. Eventually, the massive myocardial depression and infiltration led to a fatal outcome. PMID:28255325

  11. Vascular contractile reactivity in hypotension due to reduced renal reabsorption of Na(+) and restricted dietary Na().

    PubMed

    Alshahrani, Saeed; Rapoport, Robert M; Soleimani, Manoocher

    2017-03-01

    Reduced renal Na(+) reabsorption along with restricted dietary Na(+) depletes intravascular plasma volume which can then result in hypotension. Whether hypotension occurs and the magnitude of hypotension depends in part on compensatory angiotensin II-mediated increased vascular resistance. We investigated whether the ability of vascular resistance to mitigate the hypotension was compromised by decreased contractile reactivity. In vitro reactivity was investigated in aorta from mouse models of reduced renal Na(+) reabsorption and restricted dietary Na(+) associated with considerable hypotension and renin-angiotensin system activation: (1) the Na(+)-Cl(-)-Co-transporter (NCC) knockout (KO) with Na(+) restricted diet (0.1%, 2 weeks) and (2) the relatively more severe pendrin (apical chloride/bicarbonate exchanger) and NCC double KO. Contractile sensitivity to KCl, phenylephrine, and/or U46619 remained unaltered in aorta from both models. Maximal KCl and phenylephrine contraction expressed as force/aorta length from NCC KO with Na(+)-restricted diet remained unaltered, while in pendrin/NCC double KO were reduced to 49 and 64%, respectively. Wet weight of aorta from NCC KO with Na(+)-restricted diet remained unaltered, while pendrin/NCC double KO was reduced to 67%, consistent with decreased medial width determined with Verhoeff-Van Gieson stain. These findings suggest that hypotension associated with severe intravascular volume depletion, as the result of decreased renal Na(+) reabsorption, may in part be due to decreased contractile reactivity as a consequence of reduced vascular hypertrophy.

  12. Minimal Marking: A Success Story

    ERIC Educational Resources Information Center

    McNeilly, Anne

    2014-01-01

    The minimal-marking project conducted in Ryerson's School of Journalism throughout 2012 and early 2013 resulted in significantly higher grammar scores in two first-year classes of minimally marked university students when compared to two traditionally marked classes. The "minimal-marking" concept (Haswell, 1983), which requires…

  13. Case Marking Strategies in Kope.

    ERIC Educational Resources Information Center

    Clifton, John

    Case marking strategies in Kope, a Papuan language of Papua New Guinea, are analyzed in light of previous claims that most Papuan languages have one strategy for marking core relations and another for marking peripheral relations. A brief grammatical overview illustrates how core and peripheral relations are marked in Kope, including nominal case…

  14. Mark 3 system overview

    NASA Technical Reports Server (NTRS)

    Clark, T. A.

    1980-01-01

    The Mark 3 very long baseline interferometry (VLBI) system, comprising a complete end to end VLBI system optimized for both high accuracy geodesy and radio astronomy, is described. The data flow, the data base handler system, and the field station component and configurations are briefly discussed. The use of mobile and transportable stations allows measurements to be taken from a large number of sites with relatively few sets of equipment. Fixed stations form a long term reference network for tying together the measurements with the mobile and transportable stations.

  15. Meropenem population pharmacokinetics in critically ill patients with septic shock and continuous renal replacement therapy: influence of residual diuresis on dose requirements.

    PubMed

    Ulldemolins, Marta; Soy, Dolors; Llaurado-Serra, Mireia; Vaquer, Sergi; Castro, Pedro; Rodríguez, Alejandro H; Pontes, Caridad; Calvo, Gonzalo; Torres, Antoni; Martín-Loeches, Ignacio

    2015-09-01

    Meropenem dosing in critically ill patients with septic shock and continuous renal replacement therapy (CRRT) is complex, with the recommended maintenance doses being 500 mg to 1,000 mg every 8 h (q8h) to every 12 h. This multicenter study aimed to describe the pharmacokinetics (PKs) of meropenem in this population to identify the sources of PK variability and to evaluate different dosing regimens to develop recommendations based on clinical parameters. Thirty patients with septic shock and CRRT receiving meropenem were enrolled (153 plasma samples were tested). A population PK model was developed with data from 24 patients and subsequently validated with data from 6 patients using NONMEM software (v.7.3). The final model was characterized by CL = 3.68 + 0.22 · (residual diuresis/100) and V = 33.00 · (weight/73)(2.07), where CL is total body clearance (in liters per hour), residual diuresis is the volume of residual diuresis (in milliliters per 24 h), and V is the apparent volume of distribution (in liters). CRRT intensity was not identified to be a CL modifier. Monte Carlo simulations showed that to maintain concentrations of the unbound fraction (fu ) of drug above the MIC of the bacteria for 40% of dosing interval T (referred to as 40% of the ƒ uT >MIC), a meropenem dose of 500 mg q8h as a bolus over 30 min would be sufficient regardless of the residual diuresis. If 100% of the ƒ uT >MIC was chosen as the target, oligoanuric patients would require 500 mg q8h as a bolus over 30 min for the treatment of susceptible bacteria (MIC < 2 mg/liter), while patients with preserved diuresis would require the same dose given as an infusion over 3 h. If bacteria with MICs close to the resistance breakpoint (2 to 4 mg/liter) were to be treated with meropenem, a dose of 500 mg every 6 h would be necessary: a bolus over 30 min for oligoanuric patients and an infusion over 3 h for patients with preserved diuresis. Our results suggest that residual diuresis may be an easy and

  16. Body water handling in response to hypertonic-saline induced diuresis in fasting northern elephant seal pups (Mirounga angustirostris)

    NASA Technical Reports Server (NTRS)

    Ortiz, Rudy M.; Wade, Charles E.; Ortiz, C. Leo

    2003-01-01

    During natural fasting conditions in postweaned northern elephant seal (NES) (Mirounga angustirostris) pups, urinary water loss is minimized and percent total body water (TBW) is maintained constant. However, following infusion of hypertonic saline, glomerular filtration rate (GFR) and urine output increased in fasting pups. Therefore, we quantified the magnitude of the hypernatremia-induced diuresis relative to the animal's total body water (TBW) pool and the percentage of filtered water reabsorbed. Following a 24 h control period, naturally fasting NES pups (n=7) were infused (4 ml min(-1)) with hypertonic saline (16.7%) at a dose of 3 mmol NaCl kg(-1) body mass. Total body water was estimated prior to infusion by tritium dilution, GFR was estimated by standard creatinine clearance, and urine output (V) was measured for 24 h during the control and post infusion periods. Percentage of filtered water reabsorbed was calculated as (1-(V/GFR))x100. Twenty-four hours following the infusion, GFR (control: 69+/-12 ml min(-1) and post-infusion: 118+/-19 ml min(-1); mean+/-S.E.) increased 77+/-28% above control and the percentage of filtered water reabsorbed was decreased 0.4+/-0.1%. The increase in urine output (control: 218+/-47 ml d(-1) and post-infusion: 883+/-92 ml d(-1)) accounted for 1.7+/-0.2% of the pups' TBW. The hypernatremia-induced diuresis was accompanied by the loss of body water indicating the lack of water retention. Although the 77% increase in GFR was only associated with a 0.4% decrease in the percentage of filtered water reabsorbed, this decrease was significant enough to result in a 4-fold increase in urine output. Despite the observed diuresis, fasting NES pups appear to possess an efficient water recycling mechanism requiring only a small percentage of body water to excrete an excess salt load. This water recycling mechanism may allow pups to avoid negative perturbations in body water as they initiate feeding in a marine environment following the

  17. 'Non-hypotensive' hypovolaemia reduces ascending aortic dimensions in humans

    NASA Technical Reports Server (NTRS)

    Taylor, J. A.; Halliwill, J. R.; Brown, T. E.; Hayano, J.; Eckberg, D. L.

    1995-01-01

    1. The notion that small, 'non-hypotensive' reductions of effective blood volume alter neither arterial pressure nor arterial baroreceptor activity is pervasive in the experimental literature. We tested two hypotheses: (a) that minute arterial pressure and cardiac autonomic outflow changes during hypovolaemia induced by lower body suction in humans are masked by alterations in breathing, and (b) that evidence for arterial baroreflex engagement might be obtained from measurements of thoracic aorta dimensions. 2. In two studies, responses to graded lower body suction at 0 (control), 5, 10, 15, 20 and 40 mmHg were examined in twelve and ten healthy young men, respectively. In the first, arterial pressure (photoplethysmograph), R-R interval, and respiratory sinus arrhythmia amplitude (complex demodulation) were measured during uncontrolled and controlled breathing (constant breathing frequency and tidal volume). In the second, cross-sectional areas of the ascending thoracic aorta were calculated from nuclear magnetic resonance images. 3. Lower body suction with controlled breathing resulted in an increased arterial pulse pressure at mild levels (5-20 mmHg; ANOVA, P < 0.05) and a decreased arterial pulse pressure at moderate levels (40 mmHg; ANOVA, P < 0.05). Both R-R intervals and respiratory sinus arrhythmia were negatively related to lower body suction level, whether group averages (general linear regression, r > 0.92) or individual subjects (orthogonal polynomials, 12 of 12 subjects) were assessed. 4. Aortic pulse area decreased progressively and significantly during mild lower body suction, with 47% of the total decline occurring by 5 mmHg. 5. These results suggest that small reductions of effective blood volume reduce aortic baroreceptive areas and trigger haemodynamic adjustments which are so efficient that alterations in arterial pressure escape detection by conventional means.

  18. Autoregulation of cerebral blood flow in orthostatic hypotension

    NASA Technical Reports Server (NTRS)

    Novak, V.; Novak, P.; Spies, J. M.; Low, P. A.

    1998-01-01

    BACKGROUND AND PURPOSE: We sought to evaluate cerebral autoregulation in patients with orthostatic hypotension (OH). METHODS: We studied 21 patients (aged 52 to 78 years) with neurogenic OH during 80 degrees head-up tilt. Blood flow velocities (BFV) from the middle cerebral artery were continuously monitored with transcranial Doppler sonography, as were heart rate, blood pressure (BP), cardiac output, stroke volume, CO2, total peripheral resistance, and cerebrovascular resistance. RESULTS: All OH patients had lower BP (P<.0001), BFV_diastolic (P<.05), CVR (P<.007), and TPR (P<.02) during head-up tilt than control subjects. In control subjects, no correlations between BFV and BP were found during head-up tilt, suggesting normal autoregulation. OH patients could be separated into those with normal or expanded autoregulation (OH_NA; n=16) and those with autoregulatory failure (OH_AF; n=5). The OH_NA group showed either no correlation between BFV and BP (n=8) or had a positive BFV/BP correlation (R2>.75) but with a flat slope. An expansion of the "autoregulated" range was seen in some patients. The OH_AF group was characterized by a profound fall in BFV in response to a small reduction in BP (mean deltaBP <40 mm Hg; R2>.75). CONCLUSIONS: The most common patterns of cerebral response to OH are autoregulatory failure with a flat flow-pressure relationship or intact autoregulation with an expanded autoregulated range. The least common pattern is autoregulatory failure with a steep flow-pressure relationship. Patients with patterns 1 and 2 have an enhanced capacity to cope with OH, while those with pattern 3 have reduced capacity.

  19. Ultrasonography-guided percutaneous nephrolithotomy with Chinese one-shot tract dilation technique based on stimulated diuresis: A report of 67 cases.

    PubMed

    Shi, Ying; Liang, Hua-Geng; Yang, Xiong; Hai, Bo; Wang, Liang; Xing, Yi-Fei; Ju, Wen; Zeng, Fu-Qing; Zhang, Xiao-Ping; Li, Wen-Cheng

    2016-12-01

    The safety and effectiveness of a novel Chinese one-shot dilation technique based on stimulated diuresis for percutaneous nephrolithotomy (PCNL) were investigated. After the feasibility of the Chinese one-shot dilation based on stimulated diuresis was verified by an animal study, this technique was applied in the clinical practice. A total of 67 patients in our department underwent the modified PCNL from July 2014 to June 2015. After the renal infundibulum was distended by stimulated diuresis, the kidney was punctured under the ultrasonographic guidance via the fornix of the target calyx. The working channel was dilated using a special designed pencil-shaped fascial dilator. The successful access rate, nephrostomy tract creation time, pre- and postoperative hemoglobin values and serum creatinine concentrations, stone-free rate and complications were recorded and analyzed. The renal infundibulum was successfully distended in all of the patients by the diuresis treatment. Under the ultrasonographic guidance, the successful access rate was 100% and the mean tract creation time was 2.0 min (range: 1.5-5.0 min). The stone-free rate right after surgery was 91.0%. Although the postoperative hemoglobin was significantly reduced (P<0.01), transfusion was not clinically necessary. There was no significant difference in serum creatinine concentrations before and after operation (P>0.05). No severe complication occurred during or after the PCNL. It was suggested that this Chinese one-shot dilation technique based on stimulated diuresis is an efficient and safe innovation for PCNL, and is even helpful for those patients with non-dilated pelvicaliceal systems.

  20. [Role of V1- and V2-receptors in mechanism of physiological paradox--an increase of reabsorption of the solute free water and simultaneous rise of diuresis].

    PubMed

    Kanashkina, T A; Kuznetsova, A A; Shakhmatova, E I; Natochin, Iu V

    2006-10-01

    In experiments on non-anesthetized rats with administration into stomach of water (5 ml/100 g body mass) direct correlation has been found between an increase of diuresis and excretion of solute free water (r = 0.98, p < 0.01), while after injection to these animals of 5 x 10(-11) M arginine-vasotocin - between an increase of diuresis and simultaneous rise reabsorption of solute free water (r = 0.8, p < 0.01). The rise of diuresis after the vasotocin injection is due to inhibition of sodium re- absorption, with the solute excretion fraction increasing from 2.6 +/- 0.2 % to 11.9 +/- 1.2, p < 0.001. A similar physiological paradox - an increase of diuresis with the simultaneous increase of reabsorption of solute free water - has been revealed at night hours in children with tendency for nocturnal enuresis (r = 0.64, p < 0.01). Mechanism responsible for this phenomenon consists in a rise of diuresis due to a decrease of sodium ion reabsorption in the ascending Henle loop limb. A problem is discussed of the homeostatic significance of a decrease of sodium reabsorption combined with an increase of solute-free water reabsorption; it is suggested that this phenomenon is based on a redistribution of reabsorption inside the nephron - a decrease of ion and water reabsorption in the initial parts of the nephron distal segment and an increase of solute free water reabsorption with the antidiuretic hormone-stimulated high osmotic permeability of terminal parts of renal tubules. An intraperitoneal injection of V1-anatagonist (OPC-21268) decreased the natriuretic component of response to arginine-vasotocin, while injection of V2-antagonist (OPC-31260) eliminated the antidiuretic component.

  1. Dynamic FDG PET/CT imaging with diuresis demonstrates an enterovesical fistula in a lymphoma patient with repeated colon diverticulitis.

    PubMed

    Kao, Pan-Fu; Ting, Wen-Chien; Hsiao, Pei-Ching; Kao, Yu-Lin; Chang, Pai-Jung; Lee, Jong-Kang

    2013-04-01

    A 43-year-old male patient with follicular B-cell lymphoma was referred for a FDG PET/CT scan due to severe left lower abdominal pain to rule out recurrent cancer. These FDG PET/CT images and previous FDG PET/CT images 5 months ago both revealed an air bubble in the urinary bladder on the CT images. He had a recurrent urinary tract infection history for 6 months. A list-mode dynamic data acquisition with diuresis intravenous injection revealed linear FDG activity extending from the upper-left portion of the bladder to a soft tissue mass in the lower-left pelvic region. An enterovesical fistula was confirmed by surgery.

  2. The Mark 3 Haploscope

    NASA Technical Reports Server (NTRS)

    Decker, T. A.; Williams, R. E.; Kuether, C. L.; Logar, N. D.; Wyman-Cornsweet, D.

    1975-01-01

    A computer-operated binocular vision testing device was developed as one part of a system designed for NASA to evaluate the visual function of astronauts during spaceflight. This particular device, called the Mark 3 Haploscope, employs semi-automated psychophysical test procedures to measure visual acuity, stereopsis, phoria, fixation disparity, refractive state and accommodation/convergence relationships. Test procedures are self-administered and can be used repeatedly without subject memorization. The Haploscope was designed as one module of the complete NASA Vision Testing System. However, it is capable of stand-alone operation. Moreover, the compactness and portability of the Haploscope make possible its use in a broad variety of testing environments.

  3. Diuresis and reduced urinary osmolality in rats produced by small-molecule UT-A-selective urea transport inhibitors

    PubMed Central

    Esteva-Font, Cristina; Cil, Onur; Phuan, Puay-Wah; Su, Tao; Lee, Sujin; Anderson, Marc O.; Verkman, A. S.

    2014-01-01

    Urea transport (UT) proteins of the UT-A class are expressed in epithelial cells in kidney tubules, where they are required for the formation of a concentrated urine by countercurrent multiplication. Here, using a recently developed high-throughput assay to identify UT-A inhibitors, a screen of 50,000 synthetic small molecules identified UT-A inhibitors of aryl-thiazole, γ-sultambenzosulfonamide, aminocarbonitrile butene, and 4-isoxazolamide chemical classes. Structure-activity analysis identified compounds that inhibited UT-A selectively by a noncompetitive mechanism with IC50 down to ∼1 μM. Molecular modeling identified putative inhibitor binding sites on rat UT-A. To test compound efficacy in rats, formulations and administration procedures were established to give therapeutic inhibitor concentrations in blood and urine. We found that intravenous administration of an indole thiazole or a γ-sultambenzosulfonamide at 20 mg/kg increased urine output by 3–5-fold and reduced urine osmolality by ∼2-fold compared to vehicle control rats, even under conditions of maximum antidiuresis produced by 1-deamino-8-d-arginine vasopressin (DDAVP). The diuresis was reversible and showed urea > salt excretion. The results provide proof of concept for the diuretic action of UT-A-selective inhibitors. UT-A inhibitors are first in their class salt-sparing diuretics with potential clinical indications in volume-overload edemas and high-vasopressin-associated hyponatremias.—Esteva-Font, C., Cil, O., Phuan, P.-W., Su, T., Lee, S., Anderson, M. O., Verkman, A. S. Diuresis and reduced urinary osmolality in rats produced by small-molecule UT-A-selective urea transport inhibitors. PMID:24843071

  4. Diuresis and natriuresis caused by activation of VR1-positive sensory nerves in renal pelvis of rats.

    PubMed

    Zhu, Yi; Wang, Youping; Wang, Donna H

    2005-10-01

    To test the hypothesis that activation of the vanilloid receptor 1 (VR1) expressed in sensory nerves innervating the renal pelvis leads to diuresis and natriuresis, a selective VR1 receptor agonist, capsaicin (2.4 nmol), or vehicle was perfused intravenously or into the left renal pelvis of anesthetized rats at a rate without changing renal perfusion pressure. Mean arterial pressure was not altered by capsaicin administered intravenously or into the renal pelvis. Capsaicin perfusion into the left renal pelvis but not intravenously caused significant increases in urine flow rate and urinary sodium excretion bilaterally in a dose-dependent manner, which were abolished by capsazepine, a selective VR1 receptor antagonist, given ipsilaterally to the renal pelvis or by ipsilateral renal denervation. Capsaicin given intravenously or into the left renal pelvis increased plasma calcitonin gene-related peptide levels to the same extent. Increased plasma calcitonin gene-related peptide levels induced by capsaicin (68.9+/-2.8 pg/mL) perfusion into the renal pelvis was prevented either by capsazepine (22.5+/-10.1 pg/mL) given ipsilaterally into the renal pelvis or by ipsilateral renal denervation (25.9+/-2.3 pg/mL). Taken together, our data show that unilateral activation of VR1-positive sensory nerves innervating the renal pelvis leads to bilateral diuresis and natriuresis via a mechanism that is independent of plasma calcitonin gene-related peptide levels. These data suggest that VR1-positive sensory nerves in the kidney enhance renal excretory function, a mechanism that may be critically involved in sodium and fluid homeostasis.

  5. Effect of P2X4 and P2X7 receptor antagonism on the pressure diuresis relationship in rats

    PubMed Central

    Menzies, Robert I.; Unwin, Robert J.; Dash, Ranjan K.; Beard, Daniel A.; Cowley Jr., Allen W.; Carlson, Brian E.; Mullins, John J.; Bailey, Matthew A.

    2013-01-01

    Reduced glomerular filtration, hypertension and renal microvascular injury are hallmarks of chronic kidney disease, which has a global prevalence of ~10%. We have shown previously that the Fischer (F344) rat has lower GFR than the Lewis rat, and is more susceptible to renal injury induced by hypertension. In the early stages this injury is limited to the pre-glomerular vasculature. We hypothesized that poor renal hemodynamic function and vulnerability to vascular injury are causally linked and genetically determined. In the present study, normotensive F344 rats had a blunted pressure diuresis relationship, compared with Lewis rats. A kidney microarray was then interrogated using the Endeavour enrichment tool to rank candidate genes for impaired blood pressure control. Two novel candidate genes, P2rx7 and P2rx4, were identified, having a 7− and 3− fold increased expression in F344 rats. Immunohistochemistry localized P2X4 and P2X7 receptor expression to the endothelium of the pre-glomerular vasculature. Expression of both receptors was also found in the renal tubule; however there was no difference in expression profile between strains. Brilliant Blue G (BBG), a relatively selective P2X7 antagonist suitable for use in vivo, was administered to both rat strains. In Lewis rats, BBG had no effect on blood pressure, but increased renal vascular resistance, consistent with inhibition of some basal vasodilatory tone. In F344 rats BBG caused a significant reduction in blood pressure and a decrease in renal vascular resistance, suggesting that P2X7 receptor activation may enhance vasoconstrictor tone in this rat strain. BBG also reduced the pressure diuresis threshold in F344 rats, but did not alter its slope. These preliminary findings suggest a physiological and potential pathophysiological role for P2X7 in controlling renal and/or systemic vascular function, which could in turn affect susceptibility to hypertension-related kidney damage. PMID:24187541

  6. Microinjection of glycine into the hypothalamic paraventricular nucleus produces diuresis, natriuresis, and inhibition of central sympathetic outflow.

    PubMed

    Krowicki, Zbigniew K; Kapusta, Daniel R

    2011-04-01

    Strychnine-sensitive glycine receptors and glycine-immunoreactive fibers are expressed in the hypothalamic paraventricular nucleus (PVN), yet the functional significance of this innervation is unclear. Therefore, these studies examined the changes in cardiovascular and renal function and renal sympathetic nerve activity (RSNA) produced by the microinjection of glycine (5 and 50 nmol) into the PVN of conscious Sprague-Dawley rats. Microinjection of glycine into, but not outside of, the PVN dose-dependently increased urine flow rate and urinary sodium excretion and decreased RSNA. At the higher dose, PVN glycine also decreased heart rate; neither 5 nor 50 nmol PVN glycine altered mean arterial pressure. The glycine (50 nmol)-evoked diuresis and natriuresis were abolished in rats continuously infused intravenously with [Arg(8)]-vasopressin. Furthermore, chronic bilateral renal denervation prevented the bradycardia and diuresis to PVN glycine and blunted the natriuresis. In other studies, unilateral PVN pretreatment with the glycine receptor antagonist strychnine (1.6 nmol) prevented the effects of PVN glycine (50 nmol) on heart rate, RSNA, and renal excretory function. When microinjected bilaterally, PVN strychnine (1.6 nmol per site) evoked a significant increase in heart rate and RSNA without altering renal excretory function. These findings demonstrate that in conscious rats glycine acts in the PVN to enhance the renal excretion of water and sodium and decrease central sympathetic outflow to the heart and kidneys. Although endogenous PVN glycine inputs elicit a tonic control of heart rate and RSNA, the renal excretory responses to PVN glycine seem to be caused primarily by the inhibition of arginine vasopressin secretion.

  7. Patterns of renal dopamine release to regulate diuresis and natriuresis during volume expansion. Role of renal monoamine-oxidase.

    PubMed

    de Luca Sarobe, Verónica; Di Ciano, Luis; Carranza, Andrea M; Levin, Gloria; Arrizurieta, Elvira E; Ibarra, Fernando R

    2010-01-01

    Diuretic and natriuretic effects of renal dopamine (DA) are well established. However, in volume expansion the pattern of renal DA release into urine (UDAV) and the role of enzymes involved in DA synthesis/degradation have not yet been defined. The objective was to determine the pattern of UDAV during volume expansion and to characterize the involvement of monoamine-oxidase (MAO) and aromatic amino-acid decarboxylase (AADC) in this response. In this study male Wistar rats were expanded with NaCl 0.9% at a rate of 5% BWt per hour. At the beginning of expansion three groups received a single drug injection as follows: C (vehicle, Control), IMAO (MAO inhibitor Pargyline, 20 mg/kg BWt, i.v.) and BNZ (AADC inhibitor Benserazide, 25 mg/kg BWt, i.v.). Results revealed that in C rats UDAV (ng/30 min/100g BWt) increased in the first 30 min expansion from 11.5 +/- 1.20 to 21.8 +/- 3.10 (p < 0.05) and decreased thereafter. IMAO showed a similar pattern but significantly higher than C at 30 min expansion (32.5 +/- 2.20, p < 0.05). IMAO greatly reduced MAO activity from 8.29 +/- 0.35 to 1.1 +/- 0.03 nmol/mg tissue/hour and significantly increased diuresis and natriuresis over controls. BNZ abolished the early UDAV peak to 3.2+/-0.72 (p < 0.01) and though, UDAV increased over C after 60 min expansion, natriuresis and diuresis were diminished by BNZ treatment. Results indicate that an increment in renal DA release into urine occurs early in expansion and in a peak-shaped way. In this response MAO plays a predominant role.

  8. Preoperative characteristics predicting intraoperative hypotension and hypertension among hypertensives and diabetics undergoing noncardiac surgery.

    PubMed Central

    Charlson, M E; MacKenzie, C R; Gold, J P; Ales, K L; Topkins, M; Shires, G T

    1990-01-01

    We prospectively studied patients with hypertension and diabetes undergoing elective noncardiac surgery with general anesthesia to test the hypothesis that patients at high risk for prognostically significant intraoperative hemodynamic instability could be identified by their preoperative characteristics. Specifically we hypothesized that patients with a low functional capacity, decreased plasma volume, or significant cardiac comorbidity would be at high risk for intraoperative hypotension and those with a history of severe hypertension would be at risk for intraoperative hypertension. Patients who had a preoperative mean arterial pressure (MAP) greater than or equal to 110, a walking distance of less than 400 m, or a plasma volume less than 3000 cc were at increased risk of intraoperative hypotension (i.e., more than 1 hour of greater than or equal to 20 mmHg decreases in the MAP). Hypotension was also more common among patients having intra-abdominal or vascular surgery, and among those who had operations longer than 2 hours. Patients older than 70 years or with a decreased plasma volume were at increased risk of having more than 15 minutes of intraoperative elevations of greater than or equal to 20 mmHg over the preoperative MAP in combination with intraoperative hypotension; this was also more common when surgery lasted more than 2 hours. Patients who had intraoperative hypotension tended to have an immediate decrease in MAP at the onset of anesthesia and were often purposefully maintained at MAPs less than their usual level during surgery with fentanyl and neuromuscular blocking agents. Patients who had intraoperative hyper/hypotension tended to have repeated elevations in MAP above their preoperative levels during the course of surgery, and such elevations precipitated interventions with neuromuscular blocking agents and/or fentanyl. Neither pattern was more common among patients who developed net intraoperative negative fluid balances. Both hypotension and

  9. Hypotension induced by the concomitant use of a calcium-channel blocker and clarithromycin

    PubMed Central

    Takeuchi, Sayako; Tsujimoto, Toshihide

    2017-01-01

    In the elderly, calcium-channel blockers are the first-line treatment for hypertension, and macrolides are commonly prescribed antibiotics. Here we report a 78-year-old man taking nifedipine, diltiazem and carvedilol who presented with persistent hypotension and bradycardia after clarithromycin was prescribed. He was diagnosed with drug-induced hypotension and treated with fluid resuscitation and vasoactive agents. His symptoms gradually improved. He was transferred out of the intensive care unit 3 days after hospitalisation. Combining calcium-channel blockers and clarithromycin can cause vasodilatory hypotension. The concomitant use of calcium-channel blockers and macrolide antibiotics increases the levels of calcium-channel blockers in the blood as they are metabolised by cytochrome P450 3A4 (CYP3A4), which is inhibited by macrolide antibiotics. Moreover, the addition of another calcium-channel blocker and a β blocker can lower cardiac output due to bradycardia and worsen hypotension. Therefore, it is important to consider drug interactions when the cause of hypotension is unknown. PMID:28069789

  10. Subclinical decelerations during developing hypotension in preterm fetal sheep after acute on chronic lipopolysaccharide exposure

    PubMed Central

    Lear, Christopher A.; Davidson, Joanne O.; Galinsky, Robert; Yuill, Caroline A.; Wassink, Guido; Booth, Lindsea C.; Drury, Paul P.; Bennet, Laura; Gunn, Alistair J.

    2015-01-01

    Subclinical (shallow) heart rate decelerations occur during neonatal sepsis, but there is limited information on their relationship with hypotension or whether they occur before birth. We examined whether subclinical decelerations, a fall in fetal heart rate (FHR) that remained above 100 bpm, were associated with hypotension in preterm fetal sheep exposed to lipopolysaccharide (LPS). Chronically-instrumented fetal sheep at 0.7 gestation received continuous low-dose LPS infusions (n = 15, 100 ng/kg over 24 h, followed by 250 ng/kg/24 h for 96 h) or saline (n = 8). Boluses of 1 μg LPS or saline were given at 48 and 72 h. FHR variability (FHRV) was calculated, and sample asymmetry was used to assess the severity and frequency of decelerations. Low-dose LPS infusion did not affect FHR. After the first LPS bolus, 7 fetuses remained normotensive, while 8 developed hypotension (a fall in mean arterial blood pressure of ≥5 mmHg). Developing hypotension was associated with subclinical decelerations, with a corresponding increase in sample asymmetry and FHRV (p < 0.05). The second LPS bolus was associated with similar but attenuated changes in FHR and blood pressure (p < 0.05). In conclusion, subclinical decelerations are not consistently seen during prenatal exposure to LPS, but may be a useful marker of developing inflammation-related hypotension before birth. PMID:26537688

  11. Delta- and kappa-opioid receptors in the caudal midline medulla mediate haemorrhage-evoked hypotension.

    PubMed

    Henderson, Luke A; Keay, Kevin A; Bandler, Richard

    2002-04-16

    In mammals blood loss can trigger, shock, an abrupt, life-threatening hypotension and bradycardia. In the halothane-anaesthetised rat this response is blocked by inactivation of a discrete, vasodepressor area in the caudal midline medulla (CMM). Haemorrhagic shock is blocked also by systemic or ventricular injections of the opioid antagonist, naloxone. This study investigated, in the halothane anaesthetised rat, the contribution of delta-, kappa- and mu-opioid receptors in the CMM vasodepressor region to haemorrhage-evoked shock (i.e. hypotension and bradycardia) and its recovery. It was found that microinjections into the CMM of the delta-opioid receptor antagonist, naltrindole delayed and attenuated the hypotension and bradycardia evoked by haemorrhage, but did not promote recompensation. In contrast, CMM microinjections of the kappa-opioid receptor antagonist, nor-binaltorphamine, although it did not alter haemorrhage-evoked hypotension and bradycardia, did lead to a rapid restoration of AP, but not HR. CMM microinjections of the mu-opioid receptor antagonist, CTAP had no effect on haemorrhage-evoked shock or recompensation. These data indicate that delta- and kappa- (but not mu-) opioid receptor-mediated events within the CMM contribute to the hypotension and bradycardia evoked by haemorrhage and the effectiveness of naloxone in reversing shock.

  12. Refractory Hypotension after Liver Allograft Reperfusion: A Case of Dynamic Left Ventricular Outflow Tract Obstruction

    PubMed Central

    Essandoh, Michael; Otey, Andrew Joseph; Dalia, Adam; Dewhirst, Elisabeth; Springer, Andrew; Henry, Mitchell

    2016-01-01

    Hypotension after reperfusion is a common occurrence during liver transplantation following the systemic release of cold, hyperkalemic, and acidic contents of the liver allograft. Moreover, the release of vasoactive metabolites such as inflammatory cytokines and free radicals from the liver and mesentery, compounded by the hepatic uptake of blood, may also cause a decrement in systemic perfusion pressures. Thus, the postreperfusion syndrome (PRS) can materialize if hypotension and fibrinolysis occur concomitantly within 5 min of reperfusion. Treatment of the PRS may require the administration of inotropes, vasopressors, and intravenous fluids to maintain hemodynamic stability. However, the occurrence of the PRS and its treatment with inotropes and calcium chloride may lead to dynamic left ventricular outflow tract obstruction (DLVOTO) precipitating refractory hypotension. Expedient diagnosis of DLVOTO with transesophageal echocardiography is extremely vital in order to avoid potential cardiovascular collapse during this critical period. PMID:26909349

  13. Blood Pressure Drop Prediction by using HRV Measurements in Orthostatic Hypotension.

    PubMed

    Sannino, Giovanna; Melillo, Paolo; Stranges, Saverio; De Pietro, Giuseppe; Pecchia, Leandro

    2015-11-01

    Orthostatic Hypotension is defined as a reduction of systolic and diastolic blood pressure within 3 minutes of standing, and may cause dizziness and loss of balance. Orthostatic Hypotension has been considered an important risk factor for falls since 1960. This paper presents a model to predict the systolic blood pressure drop due to orthostatic hypotension, relying on heart rate variability measurements extracted from 5 minute ECGs recorded before standing. This model was developed and validated with the leave-one-out cross-validation technique involving 10 healthy subjects, and finally tested with an additional 5 healthy subjects, whose data were not used during the training and cross-validation process. The results show that the model predicts correctly the systolic blood pressure drop in 80 % of all experiments, with an error rate below the measurement error of a sphygmomanometer digital device.

  14. A rare presentation of an ancient disease: scurvy presenting as orthostatic hypotension.

    PubMed

    Zipursky, Jonathan Samuel; Alhashemi, Ahmad; Juurlink, David

    2014-05-23

    A 49-year-old man presented to hospital with severe orthostatic hypotension, gingival dysplasia and a purpuric rash involving his extremities. The orthostatic hypotension failed to respond to fluids and, on the basis of physical examination and dietary history, the patient was given a preliminary diagnosis of scurvy (ascorbic acid deficiency). Serum ascorbic acid levels were undetectable and the orthostasis was resolved within 24 h of ascorbic acid replacement. The pathogenesis of orthostatic hypotension in the setting of scurvy appears to involve impaired catecholamine synthesis and attenuated vasomotor response to α-adrenergic stimulation. We believe that this case describes a rare presentation of scurvy and highlights a previously under-reported connection between scurvy and vasomotor instability.

  15. Risk Prediction for Acute Hypotensive Patients by Using Gap Constrained Sequential Contrast Patterns

    PubMed Central

    Ghosh, Shameek; Feng, Mengling; Nguyen, Hung; Li, Jinyan

    2014-01-01

    The development of acute hypotension in a critical care patient causes decreased tissue perfusion, which can lead to multiple organ failures. Existing systems that employ population level prognostic scores to stratify the risks of critical care patients based on hypotensive episodes are suboptimal in predicting impending critical conditions, or in directing an effective goal-oriented therapy. In this work, we propose a sequential pattern mining approach which target novel and informative sequential contrast patterns for the detection of hypotension episodes. Our results demonstrate the competitiveness of the approach, in terms of both prediction performance as well as knowledge interpretability. Hence, sequential patterns-based computational biomarkers can help comprehend unusual episodes in critical care patients ahead of time for early warning systems. Sequential patterns can thus aid in the development of a powerful critical care knowledge discovery framework for facilitating novel patient treatment plans. PMID:25954447

  16. Hypotensive effect of hydroxylamine, an endogenous nitric oxide donor and SSAO inhibitor.

    PubMed

    Vidrio, H; Medina, M

    2007-01-01

    The endogenous compound hydroxylamine relaxes vascular smooth muscle in vitro, apparently through conversion to the vasodilator factor nitric oxide, but its effect on blood pressure has not been characterized. We found that in the anesthetized rat the amine elicits dose-related hypotension when administered by continuous iv infusion. In experiments designed to explore the mechanism of this effect, hydroxylamine was compared with the nitric oxide donor nitroprusside and the direct-acting vasodilator hydralazine, using pretreatments known to modify diverse mechanisms of vasodilation. Hydroxylamine hypotension was enhanced by the SSAO inhibitor isoniazid and the SSAO substrate methylamine, a pattern shared by hydralazine. Responses were blocked by the guanylate cyclase inhibitor methylene blue and were increased by the nitric oxide synthase inhibitor L-NAME, a pattern shared by nitroprusside. It was concluded that hydroxylamine exerts hypotension partly through conversion to nitric oxide and partly by a "hydralazine-like" mechanism involving SSAO inhibition.

  17. Modulation of oxidative stress and microinflammatory status by colloids in refractory dialytic hypotension

    PubMed Central

    2011-01-01

    Background Intradialytic hypotension may adversely affect the outcome of chronic hemodialysis. Therapeutic albumin has powerful anti-oxidant and anti-inflammatory properties. We have recently shown that systematic colloid infusion during hemodialysis sessions improves hemodynamic parameters in most dialysis hypotension-prone patients unresponsive to usual of preventive measures. We postulated that frequent hypotensive episodes may lead to a noxious inflammatory response mediated by oxidative stress induced by ischemia-reperfusion. The aim of this study was therefore to analyze the effect of 20% albumin and 4% gelatin infusions on oxidative stress and microinflammatory status in hypotension-prone patients unresponsive to usual preventive measures. Methods Prospective cross-over study (lasting 20 weeks) of routine infusion of 200 ml of 20% albumin versus 200 ml of 4% gelatin in 10 patients with refractory intradialytic hypotension. We analyzed the effect of 20% albumin and 4% gelatin on microinflammatory status, oxidative stress, serum nitrite and nitrate levels by analysis of variance. Results A significant decrease in serum ceruloplasmin and serum C3 was observed during the albumin period (p < 0.05, repeated measure ANOVA). A significant decrease in serum hydrogen peroxide was seen during albumin and gelatin administration (p < 0.01, repeated measure ANOVA) and a very large decrease in serum lipid peroxides was observed during the albumin period only (p < 0.01, Friedman test). Serum lactoferrin, serum proinflammatory cytokines and serum nitrite and nitrate levels remained stable during the different periods of this pilot trial. Conclusions We conclude that the improvement in microinflammatory status observed during colloid infusion in hypotension-prone dialysis patients may be related to a decrease in ischemia-reperfusion of noble organs, together with a specific reduction in oxidative stress by albumin. Trial registration ISRCTN 20957055 PMID:22013952

  18. Coronary effects of endothelin-1 and vasopressin during acute hypotension in anesthetized goats.

    PubMed

    Fernández, Nuria; Martínez, Ma Angeles; García-Villalón, Angel Luis; Monge, Luis; Diéguez, Godofredo

    2005-06-10

    Coronary effects of endothelin-1 and vasopressin during acute hypotension, and the role of NO and prostanoids in these effects were examined in anesthetized goats. Left circumflex coronary artery flow was measured electromagnetically, and hypotension was induced by constriction of the caudal vena cava in animals non-treated (7 goats) or treated with the inhibitor of NO synthesis N(w)-nitro-L-arginine methyl esther (L-NAME, 5 goats), the cyclooxygenase inhibitor meclofenamate (5 goats) or both drugs (5 goats). Under normotension (22 goats), mean arterial pressure averaged 93 +/- 3 mm Hg and coronary vascular conductance (CVC) 0.37 +/- 0.025 ml/min/mm Hg. Endothelin-1 (0.01-0.3 nmol) and vasopressin (0.03-1 nmol), intracoronarily injected, dose-dependently decreased CVC by up to 56% for endothelin-1 and 40% for vasopressin. During hypotension in every condition tested, mean arterial pressure decreased to approximately 60 mm Hg, and CVC only decreased during hypotension pretreated with L-NAME (23%) or L-NAME + meclofenamate (34%). Under non-treated hypotension, the decreases in CVC by endothelin-1 were augmented approximately 1.5 fold, and those by vasopressin were not modified. This increase in CVR by endothelin-1 was not affected by L-NAME and was reversed by meclofenamate or L-NAME + meclofenamate. The coronary effects of vasopressin were not modified by any of these treatments. Therefore, acute hypotension increases the coronary vasoconstriction in response to endothelin-1 but not to vasopressin. This increased response to endothelin-1 may be related to both inhibition of NO release and release of vasoconstrictor prostanoids.

  19. [Hemodynamic mechanism of the hypotensive action of beta-phenyl-GABA esters (phenibut)].

    PubMed

    Tiurenkov, I N

    1983-01-01

    It was established in acute and chronic experiments on cats that phenibut ethers are 7-10 times more potent than phenibut itself as regards hypotensive activity and produce inconsistent effects on the cardio- and hemodynamics. Of these ethers, methyl ether of phenibut is the most powerful agent. It causes lasting hypotension when given in doses of 1/50 and 1/30 of the LD50 at the cost of a decrease in the general peripheral resistance. At the same time, apart from raising the blood inflow to the heart and cardiac output, the drug has a compensated adverse ino- and chronotropic action on the heart.

  20. Patients' choice of portable folding chairs to reduce symptoms of orthostatic hypotension

    NASA Technical Reports Server (NTRS)

    Smit, A. A.; Wieling, W.; Opfer-Gehrking, T. L.; van Emmerik-Levelt, H. M.; Low, P. A.

    1999-01-01

    Patients with neurogenic orthostatic hypotension may use portable folding chairs to prevent or reduce symptoms of low blood pressure. However, a concomitant movement disorder may limit the use of these chairs in daily living. In this prospective study, 13 patients with orthostatic hypotension, balance disturbance associated with motor disability, or both examined three commercially available portable folding chairs. A questionnaire was used to document the characteristics in chair design that were relevant for satisfactory use to these patients. Armrests, seat width, and an adjustable sitting height were found to be important features of a portable folding chair. One chair was selected by 11 of 13 patients to fit most needs.

  1. Cerebral vasospasm following intracranial hypotension caused by cerebrospinal fluid leak from an incidental lumbar durotomy. Case report.

    PubMed

    Chaves, Claudia; Freidberg, Stephen R; Lee, Grace; Zerris, Vasilios; Ries, Sarah; Chavali, Ram

    2005-01-01

    The authors report on the unusual case of a patient with intracranial hypotension following an incidental durotomy complicated by an extensive but reversible cerebral vasospasm. Despite the dural tear repair and correction of the intracranial hypotension, the vasospasm ran its course. The precise mechanism of the cerebral vasospasm in this patient is unclear.

  2. Severe hypotension related to high negative pressure suction drainage on a thoracic epidural drain during multilevel spinal fixation.

    PubMed

    Brahmbhatt, Anjalee; Hall, Nicholas D P; Bradley, William Pierre Litherland

    2013-11-15

    Hypotension or bradycardia or both related to intracranial hypotension after craniotomy has been reported in the literature. However, such reports are uncommon with thoracic epidural drains. We describe a case in which application of high negative pressure suction to a thoracic epidural drain caused a sudden decrease in arterial blood pressure.

  3. L-653,328: an ocular hypotensive agent with modest beta receptor blocking activity

    SciTech Connect

    Sugrue, M.F.; Gautheron, P.; Grove, J.; Mallorga, P.; Viader, M.P.; Baldwin, J.J.; Ponticello, G.S.; Varga, S.L.

    1988-05-01

    L-653,328 is the acetate ester of L-652,698 ((S)-3-tert-butylamino-1-(4-(2(hydroxy)ethyl)phenoxy)2-propanol). The penetration of L-652,698 into the albino rabbit eye was enhanced when the compound was instilled as its prodrug acetate ester. The instillation (one drop of 50 microliter) of 0.01, 0.05 and 0.1% solutions of L-653,328 significantly decreased in a dose-dependent manner the elevated intraocular pressure (IOP) of alpha-chymotrypsinized rabbits by 3.2, 4.7 and 6.1 mm Hg, respectively. A 0.01% solution of L-652,698 failed to significantly lower IOP, whereas this dose of timolol (3.8 mm Hg) and betaxolol (3.3 mm Hg) was effective. L-652,698 was active at 0.05% and 0.1%. Extraocular beta-adrenoceptor blockade was quantified in ganglion-blocked, conscious rabbits by determining effects on heart rate and blood pressure changes to i.v. isoproterenol (0.5 microgram/kg). Doses of timolol blocking isoproterenol-induced hypotension and tachycardia by 50% were 0.0065% and 0.03%, respectively. The corresponding doses for betaxolol were greater than 3% (43% inhibition) and 0.3%. Heart rate and blood pressure changes to isoproterenol were blocked by 18 and 36%, respectively, after the instillation of a 3% solution of L-653,328. The reduced propensity of L-653,328 for extraocular beta-adrenoceptor blockade stems from the modest affinity of L-652,698, its active moiety, for beta-adrenoceptors. The Ki values of L-652,698 for displacement of 125I-iodocyanopindolol binding to beta 1-(left ventricle) and beta 2-binding sites (iris + ciliary body) in the rabbit were 5.7 microM and 7.3 microM, respectively. In marked contrast, the corresponding values for timolol were 12 nM and 1.8 nM.

  4. Exogenous L-arginine attenuates the effects of angiotensin II on renal hemodynamics and the pressure natriuresis-diuresis relationship.

    PubMed

    Das, Satarupa; Mattson, David L

    2014-04-01

    Administration of exogenous L-arginine (L-Arg) attenuates angiotensin-II (AngII)-mediated hypertension and kidney disease in rats. The present study assessed renal hemodynamics and pressure diuresis-natriuresis in anaesthetized rats infused with vehicle, AngII (20 ng/kg per min i.v.) or AngII + L-Arg (300 μg/kg per min i.v.). Experiments in isolated aortic rings were carried out to assess L-Arg effects on the vasculature. Increasing renal perfusion pressure (RPP) from ~100 to 140 mmHg resulted in a nine- to tenfold increase in urine flow and sodium excretion rate in control animals. In comparison, AngII infusion significantly reduced renal blood flow (RBF) and glomerular filtration rate (GFR) by 40-42%, and blunted the pressure-dependent increase in urine flow and sodium excretion rate by 54-58% at elevated RPP. Supplementation of L-Arg reversed the vasoconstrictor effects of AngII and restored pressure-dependent diuresis to levels not significantly different from control rats. Dose-dependent contraction to AngII (10(-10) mol/L to 10(-7) mol/L) was observed with a maximal force equal to 27 ± 3% of the response to 10(-5) mol/L phenylephrine. Contraction to 10(-7) mol/L AngII was blunted by 75 ± 3% with 10(-4) mol/L L-Arg. The influence of L-Arg to blunt AngII-mediated contraction was eliminated by endothelial denudation or incubation with nitric oxide synthase inhibitors. Furthermore, the addition of 10(-3) mol/L cationic or neutral amino acids, which compete with L-Arg for cellular uptake, blocked the effect of L-Arg. Anionic amino acids did not influence the effects of L-Arg on AngII-mediated contraction. These studies show that L-Arg blunts AngII-mediated vascular contraction by an endothelial- and nitric oxide synthase-dependent mechanism involving cellular uptake of L-Arg.

  5. Changes of some amino acid concentrations in the medial vestibular nucleus of conscious rats following acute hypotension.

    PubMed

    Li, Xiang-Lan; An, Ying; Jin, Qing-Hua; Kim, Min Sun; Park, Byung Rim; Jin, Yuan-Zhe

    2010-06-14

    Microdialysis and high performance liquid chromatography (HPLC) were used to measure the changes of certain amino acids in the medial vestibular nucleus (MVN) of conscious rats in order to understand whether those amino acids are involved in the regulation of blood pressure. Acute hypotension was induced by infusing sodium nitroprusside (SNP) into the femoral vein. In the control group, glutamate (Glu) release increased, though gamma-aminobutyric acid (GABA) and taurine (Tau) release decreased in the MVN following acute hypotension. In the unilateral labyrinthectomy group, the levels of Glu, GABA, and Tau were unchanged in the ipsilateral MVN to the lesion following acute hypotension. Furthermore, in the contralateral MVN to the lesion, Glu release increased, and GABA and Tau release decreased following acute hypotension. These results suggest that SNP-induced acute hypotension can influence the activity of neurons in the MVN through afferent signals from peripheral vestibular receptors, and that certain amino acid transmitters in the MVN are involved in this process.

  6. Increased diuresis, renal vascular reactivity, and blood pressure levels in young rats fed high sodium, moderately high fructose, or their association: a comparative evaluation.

    PubMed

    Da Silva, Rita de Cássia Vilhena A F; de Souza, Priscila; da Silva-Santos, José Eduardo

    2016-12-01

    Excessive intakes of sodium or fructose have been described as risk factors for hypertension. We hypothesized that even a moderately high fructose diet (6% fructose), either alone or in combination with high sodium (4% NaCl), may impair diuresis and renal and systemic vascular reactivity, contributing to the onset of high blood pressure in rats. Male Wistar rats were fed chow containing 4% NaCl (HS), 6% fructose (MHF), or both 4% NaCl and 6% fructose (HSMHF) for 6 weeks and had their diuresis, plasma creatinine, vascular reactivity of perfused kidneys and systemic arterial pressure evaluated. We found no differences in augmented diuresis among animals given HS, MHF, or HSMHF diets. After 6 weeks both the HS and HSMHF groups had increased weight in their left kidneys, but only the HSMHF group showed augmented plasma creatinine. The effects of phenylephrine on renal vascular perfusion pressure were similarly enhanced in kidneys from the HS, MHF, and HSMHF groups, but not on the systemic arterial pressure. Although when evaluated in anesthetized rats, only the HSMHF group presented augmented blood pressure, evaluation in conscious animals revealed that both the MHF and HSMHF diets, but not the HS alone, were able to induce tachycardia and hypertension. In conclusion, a MHF diet containing 6% fructose was enough to render the renal vascular bed hyperreactive to phenylephrine and to induce both hypertension and tachycardia. The combination of 6% fructose with 4% NaCl led to plasma accumulation of creatinine and accelerated the development of tachycardia.

  7. The Mark III VLBI System

    NASA Technical Reports Server (NTRS)

    Rogers, A. E. E.; Whitney, A. R.; Levine, J. I.; Nesman, E. F.; Webber, J. C.; Hinteregger, H. F.

    1988-01-01

    Geodetic measurements have errors in centimeter range. Collection of three reports describes both equipment and results of some measurements taken with Mark III very-long-baseline interferometry (VLBI) system. Has demonstrated high accuracy over short baselines, where phase-delay measurements used. Advanced hardware, called Mark III A, developed to improve system performance and efficiency. Original Mark III hardware and III A subsystem upgrades developed as part of NASA Crustal Dynamics Project at Haystack Observatory.

  8. An Approach to Mark Arthropods for Mark Capture Type Research

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A series of studies were conducted to validate methods for marking a wide variety of arthropods with inexpensive proteins for mark-capture dispersal research. The markers tested included egg albumin protein in chicken egg whites and casein protein in bovine milk. The first study qualified the effec...

  9. Improving Marking Quality through a Taxonomy of Mark Schemes

    ERIC Educational Resources Information Center

    Ahmed, Ayesha; Pollitt, Alastair

    2011-01-01

    At the heart of most assessments lies a set of questions, and those who write them must achieve "two" things. Not only must they ensure that each question elicits the kind of performance that shows how "good" pupils are at the subject, but they must also ensure that each mark scheme gives more marks to those who are…

  10. Chronic elevation of IL-1β induces diuresis via a cyclooxygenase 2-mediated mechanism.

    PubMed

    Boesen, E I

    2013-07-15

    Chronic renal inflammation is an increasingly recognized phenomenon in multiple disease states, but the impact of specific cytokines on renal function is unclear. Previously, we found that 14-day interleukin-1β (IL-1β) infusion increased urine flow in mice. To determine the mechanism by which this occurs, the current study tested the possible involvement of three classical prodiuretic pathways. Chronic IL-1β infusion significantly increased urine flow (6.5 ± 1 ml/day at day 14 vs. 2.3 ± 0.3 ml/day in vehicle group; P < 0.05) and expression of cyclooxygenase (COX)-2, all three nitric oxide synthase (NOS) isoforms, and endothelin (ET)-1 in the kidney (P < 0.05 in all cases). Urinary prostaglandin E metabolite (PGEM) excretion was also significantly increased at day 14 of IL-1β infusion (1.21 ± 0.26 vs. 0.29 ± 0.06 ng/day in vehicle-infused mice; P = 0.001). The selective COX-2 inhibitor celecoxib markedly attenuated urinary PGEM excretion and abolished the diuretic response to chronic IL-1β infusion. In contrast, deletion of NOS3, or inhibition of NOS1 with L-VNIO, did not blunt the diuretic effect of IL-1β, nor did pharmacological blockade of endothelin ETA and ETB receptors with A-182086. Consistent with a primary effect on water transport, IL-1β infusion markedly reduced inner medullary aquaporin-2 expression (P < 0.05) and did not alter urinary Na⁺ or K⁺ excretion. These data indicate a critical role for COX-2 in mediating the effects of chronic IL-1β elevation on the kidney.

  11. Regional redistribution of blood flow in the external and internal carotid arteries during acute hypotension.

    PubMed

    Ogoh, Shigehiko; Lericollais, Romain; Hirasawa, Ai; Sakai, Sadayoshi; Normand, Hervé; Bailey, Damian M

    2014-05-15

    The present study examined to what extent an acute bout of hypotension influences blood flow in the external carotid artery (ECA) and the corresponding implications for blood flow regulation in the internal carotid artery (ICA). Nine healthy male participants were subjected to an abrupt decrease in arterial pressure via the thigh-cuff inflation-deflation technique. Duplex ultrasound was employed to measure beat-to-beat ECA and ICA blood flow. Compared with the baseline normotensive control, acute hypotension resulted in a heterogeneous blood flow response. ICA blood flow initially decreased following cuff release and then returned quickly to baseline levels. In contrast, the reduction in ECA blood flow persisted for 30 s following cuff release. Thus, the contribution of common carotid artery blood flow to the ECA circulation decreased during acute hypotension (-10 ± 4%, P < 0.001). This finding suggests that a preserved reduction in ECA blood flow, as well as dynamic cerebral autoregulation likely prevent a further decrease in intracranial blood flow during acute hypotension. The peripheral vasculature of the ECA may, thus, be considered an important vascular bed for intracranial cerebral blood flow regulation.

  12. Dynamic regulation of heart rate during acute hypotension: new insight into baroreflex function

    NASA Technical Reports Server (NTRS)

    Zhang, R.; Behbehani, K.; Crandall, C. G.; Zuckerman, J. H.; Levine, B. D.; Blomqvist, C. G. (Principal Investigator)

    2001-01-01

    To examine the dynamic properties of baroreflex function, we measured beat-to-beat changes in arterial blood pressure (ABP) and heart rate (HR) during acute hypotension induced by thigh cuff deflation in 10 healthy subjects under supine resting conditions and during progressive lower body negative pressure (LBNP). The quantitative, temporal relationship between ABP and HR was fitted by a second-order autoregressive (AR) model. The frequency response was evaluated by transfer function analysis. Results: HR changes during acute hypotension appear to be controlled by an ABP error signal between baseline and induced hypotension. The quantitative relationship between changes in ABP and HR is characterized by a second-order AR model with a pure time delay of 0.75 s containing low-pass filter properties. During LBNP, the change in HR/change in ABP during induced hypotension significantly decreased, as did the numerator coefficients of the AR model and transfer function gain. Conclusions: 1) Beat-to-beat HR responses to dynamic changes in ABP may be controlled by an error signal rather than directional changes in pressure, suggesting a "set point" mechanism in short-term ABP control. 2) The quantitative relationship between dynamic changes in ABP and HR can be described by a second-order AR model with a pure time delay. 3) The ability of the baroreflex to evoke a HR response to transient changes in pressure was reduced during LBNP, which was due primarily to a reduction of the static gain of the baroreflex.

  13. Histamine-Induced Hypotension Modified by H1 and H2 Antagonists.

    DTIC Science & Technology

    The hypotensive response of monkeys to exogenous histamine was measured when the histamine was given without antagonist, after chlorpheniramine (10...percent maximal response was: without antagonist, 0.115 micrograms/kg; after chlorpheniramine , 13.5 micrograms/kg; after chlorpheniramine and

  14. Essential Hypotension Is Accompanied by Deficits in Attention and Working Memory

    ERIC Educational Resources Information Center

    Duschek, Stefan; Matthias, Ellen; Schandry, Rainer

    2005-01-01

    In the present study, the authors investigated the relationship between low blood pressure (BP) and attentional performance through the application of a multidimensional diagnostic approach. The authors compared 40 subjects with essential hypotension (mean systolic BP = 97.6 mmHg) with 40 normotensive controls (mean systolic BP = 124.1 mmHg) using…

  15. Intraspinal hemorrhage in spontaneous intracranial hypotension: link to superficial siderosis? Report of 2 cases.

    PubMed

    Schievink, Wouter I; Wasserstein, Philip; Maya, M Marcel

    2016-03-01

    Spontaneous intracranial hypotension due to a spinal CSF leak has become a well-recognized cause of headaches, but such spinal CSF leaks also are found in approximately half of patients with superficial siderosis of the CNS. It has been hypothesized that friable vessels at the site of the spinal CSF leak are the likely source of chronic bleeding in these patients, but such an intraspinal hemorrhage has never been visualized. The authors report on 2 patients with spontaneous intracranial hypotension and intraspinal hemorrhage, offering support for this hypothesis. A 33-year-old man and a 62-year-old woman with spontaneous intracranial hypotension were found to have a hemorrhage within the ventral spinal CSF collection and within the thecal sac, respectively. Treatment consisted of microsurgical repair of a ventral dural tear in the first patient and epidural blood patching in the second patient. The authors suggest that spontaneous intracranial hypotension should be included in the differential diagnosis of spontaneous intraspinal hemorrhage, and that the intraspinal hemorrhage can account for the finding of superficial siderosis when the CSF leak remains untreated.

  16. Blood pressure lowering therapy in older people: Does it really cause postural hypotension or falls?

    PubMed

    Zia, Anam; Kamaruzzaman, Shahrul Bahyah; Tan, Maw Pin

    2015-03-01

    Hypertension is a highly prevalent condition among older people, but many physicians avoid aggressive treatment in this age group due to concerns about adverse effects such as orthostatic hypotension and falls. Orthostatic hypotension, which also increases in prevalence with increasing age, has been considered to be associated with antihypertensive therapy. Both orthostatic hypotension and antihypertensive medications are considered independent yet closely related predictors for falls among older people. The prescription of antihypertensive therapy among the elderly remains a long-standing controversy in geriatric medicine due to ongoing concerns about potential complications such as falls, despite conclusive evidence supporting the treatment of hypertension even among the very elderly. However, recent evidence suggests a dose-dependent relationship between blood pressure lowering therapy and falls among older individuals with preexisting risk factors for falls. In response to the spate of revisions in hypertension treatment targets for older patients in international guidelines and the recent evidence on antihypertensive therapy and falls, this review article examines the complex relationship between hypertension, antihypertensives, orthostatic hypotension, and falls among older patients.

  17. Intracranial hypotension in the setting of concurrent perineural cyst rupture and subarachnoid hemorrhage.

    PubMed

    Sivakumar, Walavan; Ravindra, Vijay M; Cutler, Aaron; Couldwell, William T

    2014-06-01

    Although most patients with intracranial hypotension typically present with headaches, the rest of the clinical spectrum is characteristically non-specific and often quite variable. In a patient with concurrent pathologies that can produce a similar clinical picture, a high index of suspicion must be maintained to achieve the correct diagnosis. The authors report a patient with intracranial hypotension in the setting of concurrent perineural cyst rupture and subarachnoid hemorrhage. A 63-year-old woman with a family history of ruptured intracranial aneurysms presented after a sudden thunderclap headache and was found to have diffuse subarachnoid hemorrhage. Imaging revealed anterior communicating and superior hypophyseal artery aneurysms. Following the uneventful clipping of both aneurysms, the patient experienced a delayed return to her neurological baseline. After it was noted that the patient had an improved neurological examination when she was placed supine, further investigation confirmed intracranial hypotension from perineural cyst rupture. The patient improved and returned to her neurological baseline after undergoing a high-volume blood patch and remained neurologically intact at postoperative follow-up. Although intracranial hypotension is known to be commonly associated with cerebrospinal fluid leak, its causal and temporal relationship with subarachnoid hemorrhage has yet to be elucidated.

  18. Effects of hemorrhagic hypotension on tyrosine concentrations in rat spinal cord and plasma

    NASA Technical Reports Server (NTRS)

    Conlay, L. A.; Maher, T. J.; Roberts, C. H.; Wurtman, R. J.

    1988-01-01

    Tyrosine is the precursor for catecholamine neurotransmitters. When catecholamine-containing neurons are physiologically active (as sympathoadrenal cells are in hypotension), tyrosine administration increases catecholamine synthesis and release. Since hypotension can alter plasma amino acid composition, the effects of an acute hypotensive insult on tyrosine concentrations in plasma and spinal cord were examined. Rats were cannulated and bled until the systolic blood pressure was 50 mmHg, or were kept normotensive for 1 h. Tyrosine and other large neutral amino acids (LNAA) known to compete with tyrosine for brain uptake were assayed in plasma and spinal cord. The rate at which intra-arterial (H-3)tyrosine disappeared from the plasma was also estimated in hemorrhaged and control rats. In plasma of hemorrhaged animals, both the tyrosine concentration and the tyrosine/LNAA ratio was elevated; moreover, the disappearance of (H-3)tyrosine was slowed. Tyrosine concentrations also increased in spinal cords of hemorrhaged-hypotensive rats when compared to normotensive controls. Changes in plasma amino acid patterns may thus influence spinal cord concentrations of amino acid precursors for neurotransmitters during the stress of hemorrhagic shock.

  19. Hypovolemia-induced Orthostatic Hypotension Relates To Hypo-sympathetic Responsiveness

    NASA Technical Reports Server (NTRS)

    Meck, Janice V.

    2007-01-01

    We report a new model which uses hypovolemia to force humans into a hemodynamic state that is similar to that after spaceflight. This model can be used to test candidate countermeasures for postflight orthostatic hypotension and to identify crewmembers who will be most susceptible to that symptom on landing day.

  20. Influence of population and exercise protocol characteristics on hemodynamic determinants of post-aerobic exercise hypotension.

    PubMed

    Brito, L C; Queiroz, A C C; Forjaz, C L M

    2014-08-01

    Due to differences in study populations and protocols, the hemodynamic determinants of post-aerobic exercise hypotension (PAEH) are controversial. This review analyzed the factors that might influence PAEH hemodynamic determinants, through a search on PubMed using the following key words: "postexercise" or "post-exercise" combined with "hypotension", "blood pressure", "cardiac output", and "peripheral vascular resistance", and "aerobic exercise" combined only with "blood pressure". Forty-seven studies were selected, and the following characteristics were analyzed: age, gender, training status, body mass index status, blood pressure status, exercise intensity, duration and mode (continuous or interval), time of day, and recovery position. Data analysis showed that 1) most postexercise hypotension cases are due to a reduction in systemic vascular resistance; 2) age, body mass index, and blood pressure status influence postexercise hemodynamics, favoring cardiac output decrease in elderly, overweight, and hypertensive subjects; 3) gender and training status do not have an isolated influence; 4) exercise duration, intensity, and mode also do not affect postexercise hemodynamics; 5) time of day might have an influence, but more data are needed; and 6) recovery in the supine position facilitates systemic vascular resistance decrease. In conclusion, many factors may influence postexercise hypotension hemodynamics, and future studies should directly address these specific influences because different combinations may explain the observed variability in postexercise hemodynamic studies.

  1. Caffeine-induced natriuresis and diuresis via blockade of hepatic adenosine-mediated sensory nerves and a hepatorenal reflex.

    PubMed

    Ming, Zhi; Lautt, W Wayne

    2010-11-01

    The hepatorenal reflex, activated by intrahepatic adenosine, is involved in the regulation of urine production in healthy rats and renal pathogenesis secondary to liver injury. Hepatic adenosine A1 receptors regulate the hepatorenal reflex. The aim of the present study was to evaluate whether caffeine mediates renal natriuresis and diuresis in healthy and diseased liver through this mechanism. Rats were anesthetized and instrumented to monitor systemic, hepatic, and renal circulation and urine production. Intrahepatic (intraportal but not intravenous) caffeine (5 mg·kg-1) increased urine flow (~82%) in healthy rats. This effect was abolished by liver denervation. Intraportal infusion of adenosine decreased urine production, and this response was abolished by intraportal but not intravenous caffeine. Liver injury was induced by intraperitoneal injection of thioacetamide (500 mg·kg-1), and functional assessment was performed 24 h later. Liver injury was associated with lower (~30%) glomerular filtration rate, lower (~18%) renal arterial blood flow, and lower urine production. Intraportal but not intravenous caffeine improved basal urine production and renal ability to increase urine production in response to saline overload. The liver-dependent diuretic effect of caffeine is consistent with the hypothesis for the adenosine-mediated mechanism of hepatorenal syndrome.

  2. Diuresis and reduced urinary osmolality in rats produced by small-molecule UT-A-selective urea transport inhibitors.

    PubMed

    Esteva-Font, Cristina; Cil, Onur; Phuan, Puay-Wah; Su, Tao; Lee, Sujin; Anderson, Marc O; Verkman, A S

    2014-09-01

    Urea transport (UT) proteins of the UT-A class are expressed in epithelial cells in kidney tubules, where they are required for the formation of a concentrated urine by countercurrent multiplication. Here, using a recently developed high-throughput assay to identify UT-A inhibitors, a screen of 50,000 synthetic small molecules identified UT-A inhibitors of aryl-thiazole, γ-sultambenzosulfonamide, aminocarbonitrile butene, and 4-isoxazolamide chemical classes. Structure-activity analysis identified compounds that inhibited UT-A selectively by a noncompetitive mechanism with IC50 down to ∼1 μM. Molecular modeling identified putative inhibitor binding sites on rat UT-A. To test compound efficacy in rats, formulations and administration procedures were established to give therapeutic inhibitor concentrations in blood and urine. We found that intravenous administration of an indole thiazole or a γ-sultambenzosulfonamide at 20 mg/kg increased urine output by 3-5-fold and reduced urine osmolality by ∼2-fold compared to vehicle control rats, even under conditions of maximum antidiuresis produced by 1-deamino-8-D-arginine vasopressin (DDAVP). The diuresis was reversible and showed urea > salt excretion. The results provide proof of concept for the diuretic action of UT-A-selective inhibitors. UT-A inhibitors are first in their class salt-sparing diuretics with potential clinical indications in volume-overload edemas and high-vasopressin-associated hyponatremias.

  3. Chloride channels in stellate cells are essential for uniquely high secretion rates in neuropeptide-stimulated Drosophila diuresis.

    PubMed

    Cabrero, Pablo; Terhzaz, Selim; Romero, Michael F; Davies, Shireen A; Blumenthal, Edward M; Dow, Julian A T

    2014-09-30

    Epithelia frequently segregate transport processes to specific cell types, presumably for improved efficiency and control. The molecular players underlying this functional specialization are of particular interest. In Drosophila, the renal (Malpighian) tubule displays the highest per-cell transport rates known and has two main secretory cell types, principal and stellate. Electrogenic cation transport is known to reside in the principal cells, whereas stellate cells control the anion conductance, but by an as-yet-undefined route. Here, we resolve this issue by showing that a plasma membrane chloride channel, encoded by ClC-a, is exclusively expressed in the stellate cell and is required for Drosophila kinin-mediated induction of diuresis and chloride shunt conductance, evidenced by chloride ion movement through the stellate cells, leading to depolarization of the transepithelial potential. By contrast, ClC-a knockdown had no impact on resting secretion levels. Knockdown of a second CLC gene showing highly abundant expression in adult Malpighian tubules, ClC-c, did not impact depolarization of transepithelial potential after kinin stimulation. Therefore, the diuretic action of kinin in Drosophila can be explained by an increase in ClC-a-mediated chloride conductance, over and above a resting fluid transport level that relies on other (ClC-a-independent) mechanisms or routes. This key segregation of cation and anion transport could explain the extraordinary fluid transport rates displayed by some epithelia.

  4. Opportunities for Web-based Drug Repositioning: Searching for Potential Antihypertensive Agents with Hypotension Adverse Events

    PubMed Central

    Wang, Kejian; Wan, Mei; Wang, Rui-Sheng

    2016-01-01

    Background Drug repositioning refers to the process of developing new indications for existing drugs. As a phenotypic indicator of drug response in humans, clinical side effects may provide straightforward signals and unique opportunities for drug repositioning. Objective We aimed to identify drugs frequently associated with hypotension adverse reactions (ie, the opposite condition of hypertension), which could be potential candidates as antihypertensive agents. Methods We systematically searched the electronic records of the US Food and Drug Administration (FDA) Adverse Event Reporting System (FAERS) through the openFDA platform to assess the association between hypotension incidence and antihypertensive therapeutic effect regarding a list of 683 drugs. Results Statistical analysis of FAERS data demonstrated that those drugs frequently co-occurring with hypotension events were more likely to have antihypertensive activity. Ranked by the statistical significance of frequent hypotension reporting, the well-known antihypertensive drugs were effectively distinguished from others (with an area under the receiver operating characteristic curve > 0.80 and a normalized discounted cumulative gain of 0.77). In addition, we found a series of antihypertensive agents (particularly drugs originally developed for treating nervous system diseases) among the drugs with top significant reporting, suggesting the good potential of Web-based and data-driven drug repositioning. Conclusions We found several candidate agents among the hypotension-related drugs on our list that may be redirected for lowering blood pressure. More important, we showed that a pharmacovigilance system could alternatively be used to identify antihypertensive agents and sustainably create opportunities for drug repositioning. PMID:27036325

  5. Effect of perturbations and a meal on superior mesenteric artery flow in patients with orthostatic hypotension

    NASA Technical Reports Server (NTRS)

    Fujimura, J.; Camilleri, M.; Low, P. A.; Novak, V.; Novak, P.; Opfer-Gehrking, T. L.

    1997-01-01

    Our aims were to evaluate to role of superior mesenteric blood flow in the pathophysiology of orthostatic hypotension in patients with generalized autonomic failure. METHODS: Twelve patients with symptomatic neurogenic orthostatic hypotension and 12 healthy controls underwent superior mesenteric artery flow measurements using Doppler ultrasonography during head-up tilt and tilt plus meal ingestion. Autonomic failure was assessed using standard tests of the function of the sympathetic adrenergic, cardiovagal and postganglionic sympathetic sudomotor function. RESULTS: Superior mesenteric flow volume and time-averaged velocity were similar in patients and controls at supine rest; however, responses to cold pressor test and upright tilt were attenuated (p < 0.05) in patients compared to controls. Head-up tilt after the meal evoked a profound fall of blood pressure and mesenteric blood flow in the patients; the reduction of mesenteric blood flow correlated (r = 0.89) with the fall of blood pressure in these patients, providing another manifestation of failed baroreflexes. We make the novel finding that the severity of postprandial orthostatic hypotension regressed negatively with the postprandial increase in mesenteric flow in patients with orthostatic hypotension. CONCLUSION: Mesenteric flow is under baroreflex control, which when defective, results in, or worsens orthostatic hypotension. Its large size and baroreflexivity renders it quantitatively important in the maintenance of postural normotension. The effects of orthostatic stress can be significantly attenuated by reducing the splanchnic-mesenteric volume increase in response to food. Evaluation of mesenteric flow in response to eating and head-up tilt provide important information on intra-abdominal sympathetic adrenergic function, and the ability of the patient to cope with orthostatic stress.

  6. Neurogenic orthostatic hypotension: a double-blind, placebo-controlled study with midodrine

    NASA Technical Reports Server (NTRS)

    Jankovic, J.; Gilden, J. L.; Hiner, B. C.; Kaufmann, H.; Brown, D. C.; Coghlan, C. H.; Rubin, M.; Fouad-Tarazi, F. M.

    1993-01-01

    PURPOSE: To investigate the efficacy and safety of midodrine for treatment of patients with orthostatic hypotension due to autonomic failure. PATIENTS: Ninety-seven patients with orthostatic hypotension were randomized in a 4-week, double-blinded, placebo-controlled study with a 1-week placebo run-in period. Patients ranged in age from 22 to 86 years (mean: 61 years). METHODS: After a 1-week run-in phase, either placebo or midodrine at a dose of 2.5 mg, 5 mg, or 10 mg was administered three times a day for 4 weeks. Both the placebo group and the 2.5-mg midodrine group received constant doses throughout the double-blind phase. The patients receiving 5 mg or 10 mg of midodrine were given doses that were increased at weekly intervals by 2.5-mg increments until the designated dose was reached. Efficacy evaluations were based on an improvement at 1-hour postdose in standing systolic blood pressure and in symptoms of orthostatic hypotension (syncope, dizziness/lightheadedness, weakness/fatigue, and low energy level). RESULTS: Midodrine (10 mg) increased standing systolic blood pressure by 22 mm Hg (28%, p < 0.001 versus placebo). Midodrine improved (p < 0.05) the following symptoms of orthostatic hypotension compared to placebo: dizziness/lightheadedness, weakness/fatigue, syncope, low energy level, impaired ability to stand, and feelings of depression. The overall side effects were mainly mild to moderate. One or more side effects were reported by 22% of the placebo group compared with 27% of the midodrine-treated group. Scalp pruritus/tingling, which was reported by 10 of 74 (13.5%) of the midodrine-treated patients, was most frequent. Other reported side effects included supine hypertension (8%) and feelings of urinary urgency (4%). CONCLUSION: We conclude that midodrine is an effective and well-tolerated treatment for moderate-to-severe orthostatic hypotension associated with autonomic failure.

  7. Optimizing the respiratory pump: harnessing inspiratory resistance to treat systemic hypotension.

    PubMed

    Convertino, Victor A; Ryan, Kathy L; Rickards, Caroline A; Glorsky, Steven L; Idris, Ahamed H; Yannopoulos, Demetris; Metzger, Anja; Lurie, Keith G

    2011-06-01

    We review the physiology and affects of inspiration through a low level of added resistance for the treatment of hypotension. Recent animal and clinical studies demonstrated that one of the body's natural response mechanisms to hypotension is to harness the respiratory pump to increase circulation. That finding is consistent with observations, in the 1960s, about the effect of lowering intrathoracic pressure on key physiological and hemodynamic variables. We describe studies that focused on the fundamental relationship between the generation of negative intrathoracic pressure during inspiration through a low level of resistance created by an impedance threshold device and the physiologic sequelae of a respiratory pump. A decrease in intrathoracic pressure during inspiration through a fixed resistance resulting in a pressure difference of 7 cm H(2)O has multiple physiological benefits, including: enhanced venous return and cardiac stroke volume, lower intracranial pressure, resetting of the cardiac baroreflex, elevated cerebral blood flow oscillations, increased tissue blood flow/pressure gradient, and maintenance of the integrity of the baroreflex-mediated coherence between arterial pressure and sympathetic nerve activity. While breathing has traditionally been thought primarily to provide gas exchange, studies of the mechanisms involved in animals and humans provide the physiological underpinnings for "the other side of breathing": to increase circulation to the heart and brain, especially in the setting of physiological stress. The existing results support the use of the intrathoracic pump to treat clinical conditions associated with hypotension, including orthostatic hypotension, hypotension during and after hemodialysis, hemorrhagic shock, heat stroke, septic shock, and cardiac arrest. Harnessing these fundamental mechanisms that control cardiopulmonary physiology provides new opportunities for respiratory therapists and others who have traditionally focused on

  8. Swash mark and grain flow

    USGS Publications Warehouse

    Sallenger,, Asbury H.

    1981-01-01

    Swash marks composed entirely of coarse sand are commonly found on coarse-sand beaches. These swash marks are 10 to 30 centimeters in width and a few millimeters to one centimeter in height. Previous observations, mostly on finer-sand beaches, indicate swash marks are seldom over a few millimeters in height and are commonly composed of material readily floated by surface tension (e.g., mica flakes and shell fragments). Swash marks composed of coarse sand have both fining seaward and fining with depth trends in grain size. Apparently, the leading margin of a wave upwash drives a highly concentrated flow of grains in which both grain size and grain velocity decrease with depth. Therefore, large grains are transported at greater velocities than are smaller grains. Thus, at the maximum advance of an upwash, a swash mark is deposited which has the observed fining seaward and fining with depth trends in grain size.

  9. Higher incidence of hypotension episodes in women during the sub-acute phase of ST elevation myocardial infarction and relationship to covariates

    PubMed Central

    Kala, Petr; Andrsova, Irena; Benesova, Klara; Holicka, Maria; Jarkovsky, Jiri; Hnatkova, Katerina; Koc, Lumir; Mikolaskova, Monika; Novakova, Tereza; Ondrus, Tomas; Privarova, Lenka; Spinar, Jindrich; Malik, Marek

    2017-01-01

    Objective The introduction of primary percutaneous coronary intervention (PPCI) has modified the profile of ST elevation myocardial infarction (STEMI) patients. Occurrence and prognostic significance of hypotension episodes are not known in PPCI treated STEMI patients. It is also not known whether and/or how the hypotension episodes correlate with the degree of myocardial damage and whether there are any sex differences. Methods Data of 293 consecutive STEMI patients (189 males) treated by PPCI and without cardiogenic shock were analyzed. Blood pressure was measured noninvasively. A hypotensive episode was defined as a systolic blood pressure below 90 mmHg over a period of at least 30 minutes. Results A hypotensive episode was observed in 92 patients (31.4%). Female sex was the strongest independent predictor of hypotension episodes (p < 0.0001), while there was no relationship to electrocardiographic STEMI localization. Hypotensive patients had significantly higher levels of troponin T and brain natriuretic peptide; hypotensive episodes were particularly frequent in women with increased troponin T. Treatment with angiotensin-converting enzyme inhibitor (ACEI), angiotensin receptor blocker (ARB) and betablockers was less frequent in hypotensive patients. After a mean 20-month follow-up, all-cause mortality did not differ between hypotensive patients and others. However, mortality in hypotensive patients who did not tolerate ACEI/ARB therapy was significantly higher compared to other hypotensive patients (p = 0.016). Conclusion Hypotension episodes are not uncommon in the sub-acute phase of contemporarily treated STEMI patients with a striking difference between sexes—female sex was the strongest independent predictor of hypotension episodes. Hypotensive episodes may lead to a delay in pharmacotherapy which influences prognosis. Higher incidence of hypotension in women could at least partially explain the sex-related differences in the use of cardiovascular

  10. Renal medullary ETB receptors produce diuresis and natriuresis via NOS1.

    PubMed

    Nakano, Daisuke; Pollock, Jennifer S; Pollock, David M

    2008-05-01

    Endothelin-1 (ET-1) plays an important role in the regulation of salt and water excretion in the kidney. Considerable in vitro evidence suggests that the renal medullary ET(B) receptor mediates ET-1-induced inhibition of electrolyte reabsorption by stimulating nitric oxide (NO) production. The present study was conducted to test the hypothesis that NO synthase 1 (NOS1) and protein kinase G (PKG) mediate the diuretic and natriuretic effects of ET(B) receptor stimulation in vivo. Infusion of the ET(B) receptor agonist sarafotoxin S6c (S6c: 0.45 microg x kg(-1) x h(-1)) in the renal medulla of anesthetized, male Sprague-Dawley rats markedly increased the urine flow (UV) and urinary sodium excretion (UNaV) by 67 and 120%, respectively. This was associated with an increase in medullary cGMP content but did not affect blood pressure. In addition, S6c-induced diuretic and natriuretic responses were absent in ET(B) receptor-deficient rats. Coinfusion of N(G)-propyl-l-arginine (10 microg x kg(-1) x h(-1)), a selective NOS1 inhibitor, suppressed S6c-induced increases in UV, UNaV, and medullary cGMP concentrations. Rp-8-Br-PET-cGMPS (10 microg x kg(-1) x h(-1)) or RQIKIWFQNRRMKWKK-LRK(5)H-amide (18 microg x kg(-1) x h(-1)), a PKG inhibitor, also inhibited S6c-induced increases in UV and UNaV. These results demonstrate that renal medullary ET(B) receptor activation induces diuretic and natriuretic responses through a NOS1, cGMP, and PKG pathway.

  11. Mark-specific hazard ratio model with missing multivariate marks.

    PubMed

    Juraska, Michal; Gilbert, Peter B

    2016-10-01

    An objective of randomized placebo-controlled preventive HIV vaccine efficacy (VE) trials is to assess the relationship between vaccine effects to prevent HIV acquisition and continuous genetic distances of the exposing HIVs to multiple HIV strains represented in the vaccine. The set of genetic distances, only observed in failures, is collectively termed the 'mark.' The objective has motivated a recent study of a multivariate mark-specific hazard ratio model in the competing risks failure time analysis framework. Marks of interest, however, are commonly subject to substantial missingness, largely due to rapid post-acquisition viral evolution. In this article, we investigate the mark-specific hazard ratio model with missing multivariate marks and develop two inferential procedures based on (i) inverse probability weighting (IPW) of the complete cases, and (ii) augmentation of the IPW estimating functions by leveraging auxiliary data predictive of the mark. Asymptotic properties and finite-sample performance of the inferential procedures are presented. This research also provides general inferential methods for semiparametric density ratio/biased sampling models with missing data. We apply the developed procedures to data from the HVTN 502 'Step' HIV VE trial.

  12. CE Marking - the Essential Requirements

    NASA Astrophysics Data System (ADS)

    Playle, Mervyn

    The European Union (EU) harmonisation project introduced the CE marking of products to enable the free, unhindered movement of goods throughout the European market. The CE mark replaced the EC mark in the mid 1990s and is fundamental to the New Approach Directives. When a product falls within the scope of a New Approach Directive the manufacturer must comply with the 'goal setting' essential requirements of the directive, to follow one of the conformity assessment procedures provided for, and to draw up the technical documentation specified. Although not mandatory, a manufacturer can choose to satisfy the essential requirements through the application of European harmonised standards.

  13. 49 CFR 172.304 - Marking requirements.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... SECURITY PLANS Marking § 172.304 Marking requirements. (a) The marking required in this subpart— (1) Must... labels or attachments; and (4) Must be located away from any other marking (such as advertising)...

  14. 19 CFR 134.21 - Special marking.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... COUNTRY OF ORIGIN MARKING Marking of Containers or Holders § 134.21 Special marking. This subpart includes only country of origin marking requirements and exceptions under section 304(b), Tariff Act of 1930,...

  15. Inflectional marking in Hungarian aphasics.

    PubMed

    MacWhinney, B; Osmán-Sági, J

    1991-08-01

    How do aphasics deal with the rich inflectional marking available in agglutinative languages like Hungarian? For the Hungarian noun alone, aphasics have to deal with over 15 basic case markings and dozens of possible combinations of these basic markings. Using the picture description task of MacWhinney and Bates (1978), this study examined the use of inflectional markings in nine Broca's and five Wernicke's aphasic speakers of Hungarian. The analysis focused on subject, direct object, indirect object, and locative nominal arguments. Compared to normals, both groups had a much higher rate of omission of all argument types. Subject ellipsis was particularly strong, as it is in normal Hungarian. There was a tendency for Broca's to omit the indirect object and for Wernicke's to omit the direct object. Across argument types, Wernicke's had a much higher level of pronoun usage than did Broca's. Broca's also showed a very high level of article omission. Compared to similar data reported by Slobin (this issue) for Turkish, the Hungarian aphasics showed an elevated level of omission of case markings. Addition errors were quite rare, but there were 14 substitutions of one case marking for another. These errors all involved the substitution of some close semantic competitor. There were no errors in the basic rules for vowel harmony or morpheme order. Overall the results paint a picture of a group of individuals whose grammatical abilities are damaged and noisy, but still largely functional. Neither the view of Broca's as agrammatic nor the view of Wernicke's as paragrammatic was strongly supported.

  16. Vhl deletion in renal epithelia causes HIF-1α-dependent, HIF-2α-independent angiogenesis and constitutive diuresis

    PubMed Central

    Schönenberger, Désirée; Rajski, Michal; Harlander, Sabine; Frew, Ian J.

    2016-01-01

    One of the earliest requirements for the formation of a solid tumor is the establishment of an adequate blood supply. Clear cell renal cell carcinomas (ccRCC) are highly vascularized tumors in which the earliest genetic event is most commonly the biallelic inactivation of the VHL tumor suppressor gene, leading to constitutive activation of the HIF-1α and HIF-2α transcription factors, which are known angiogenic factors. However it remains unclear whether either or both HIF-1α or HIF-2α stabilization in normal renal epithelial cells are necessary or sufficient for alterations in blood vessel formation. We show that renal epithelium-specific deletion of Vhl in mice causes increased medullary vascularization and that this phenotype is completely rescued by Hif1a co-deletion, but not by co-deletion of Hif2a. A physiological consequence of changes in the blood vessels of the vasa recta in Vhl-deficient mice is a diabetes insipidus phenotype of excretion of large amounts of highly diluted urine. This constitutive diuresis is fully compensated by increased water consumption and mice do not show any signs of dehydration, renal failure or salt wasting and blood electrolyte levels remain unchanged. Co-deletion of Hif1a, but not Hif2a, with Vhl, fully restored kidney morphology and function, correlating with the rescue of the vasculature. We hypothesize that the increased medullary vasculature alters salt uptake from the renal interstitium, resulting in a disruption of the osmotic gradient and impaired urinary concentration. Taken together, our study characterizes a new mouse model for a form of diabetes insipidus and non-obstructive hydronephrosis and provides new insights into the physiological and pathophysiological effects of HIF-1α stabilization on the vasculature in the kidney. PMID:27528422

  17. Vhl deletion in renal epithelia causes HIF-1α-dependent, HIF-2α-independent angiogenesis and constitutive diuresis.

    PubMed

    Schönenberger, Désirée; Rajski, Michal; Harlander, Sabine; Frew, Ian J

    2016-09-20

    One of the earliest requirements for the formation of a solid tumor is the establishment of an adequate blood supply. Clear cell renal cell carcinomas (ccRCC) are highly vascularized tumors in which the earliest genetic event is most commonly the biallelic inactivation of the VHL tumor suppressor gene, leading to constitutive activation of the HIF-1α and HIF-2α transcription factors, which are known angiogenic factors. However it remains unclear whether either or both HIF-1α or HIF-2α stabilization in normal renal epithelial cells are necessary or sufficient for alterations in blood vessel formation. We show that renal epithelium-specific deletion of Vhl in mice causes increased medullary vascularization and that this phenotype is completely rescued by Hif1a co-deletion, but not by co-deletion of Hif2a. A physiological consequence of changes in the blood vessels of the vasa recta in Vhl-deficient mice is a diabetes insipidus phenotype of excretion of large amounts of highly diluted urine. This constitutive diuresis is fully compensated by increased water consumption and mice do not show any signs of dehydration, renal failure or salt wasting and blood electrolyte levels remain unchanged. Co-deletion of Hif1a, but not Hif2a, with Vhl, fully restored kidney morphology and function, correlating with the rescue of the vasculature. We hypothesize that the increased medullary vasculature alters salt uptake from the renal interstitium, resulting in a disruption of the osmotic gradient and impaired urinary concentration. Taken together, our study characterizes a new mouse model for a form of diabetes insipidus and non-obstructive hydronephrosis and provides new insights into the physiological and pathophysiological effects of HIF-1α stabilization on the vasculature in the kidney.

  18. Pharmacologic inhibition of the renal outer medullary potassium channel causes diuresis and natriuresis in the absence of kaliuresis.

    PubMed

    Garcia, Maria L; Priest, Birgit T; Alonso-Galicia, Magdalena; Zhou, Xiaoyan; Felix, John P; Brochu, Richard M; Bailey, Timothy; Thomas-Fowlkes, Brande; Liu, Jessica; Swensen, Andrew; Pai, Lee-Yuh; Xiao, Jianying; Hernandez, Melba; Hoagland, Kimberly; Owens, Karen; Tang, Haifeng; de Jesus, Reynalda K; Roy, Sophie; Kaczorowski, Gregory J; Pasternak, Alexander

    2014-01-01

    The renal outer medullary potassium (ROMK) channel, which is located at the apical membrane of epithelial cells lining the thick ascending loop of Henle and cortical collecting duct, plays an important role in kidney physiology by regulating salt reabsorption. Loss-of-function mutations in the human ROMK channel are associated with antenatal type II Bartter's syndrome, an autosomal recessive life-threatening salt-wasting disorder with mild hypokalemia. Similar observations have been reported from studies with ROMK knockout mice and rats. It is noteworthy that heterozygous carriers of Kir1.1 mutations associated with antenatal Bartter's syndrome have reduced blood pressure and a decreased risk of developing hypertension by age 60. Although selective ROMK inhibitors would be expected to represent a new class of diuretics, this hypothesis has not been pharmacologically tested. Compound A [5-(2-(4-(2-(4-(1H-tetrazol-1-yl)phenyl)acetyl)piperazin-1-yl)ethyl)isobenzofuran-1(3H)-one)], a potent ROMK inhibitor with appropriate selectivity and characteristics for in vivo testing, has been identified. Compound A accesses the channel through the cytoplasmic side and binds to residues lining the pore within the transmembrane region below the selectivity filter. In normotensive rats and dogs, short-term oral administration of compound A caused concentration-dependent diuresis and natriuresis that were comparable to hydrochlorothiazide. Unlike hydrochlorothiazide, however, compound A did not cause any significant urinary potassium losses or changes in plasma electrolyte levels. These data indicate that pharmacologic inhibition of ROMK has the potential for affording diuretic/natriuretic efficacy similar to that of clinically used diuretics but without the dose-limiting hypokalemia associated with the use of loop and thiazide-like diuretics.

  19. [Relationship between regulation effect of salvia miltiorrhiza on AQP2 in kidney and promoting blood circulation and diuresis].

    PubMed

    Dong, Xiao-Jing; Guo, Liang-Feng; Yao, Rui; Xue, Song-Yan; Li, Feng

    2014-08-01

    Partial nature of "promoting blood circulation and dieresis" of Salvia Miltiorrhizain was initially demonstrated by investigating the regulation effect of AQP2 expression in kidney of trauma blood stasis model rats with the Salvia Miltiorrhizain so as to provide guidance for its clinical deployment of administration. Random allocation was taken to averagely divide 30 SD rats into two groups: 10 rats in normal group and 20 rats in blood stasis syndrome group. Trauma blood stasis rat model was established by quantitatively beating. Then the rat model group was divided into model group and salvia group. After 7 days of treatment, the rat kidney AQP2 expression was detected, the content of urine AQP2 was compared and the damaged local muscle and kidney pathological changes were observed by immunohistochemical method and western blot method. Compared with that of the normal group, rats in model group had inflammatory cells infiltration, blood stasis and edema of the injured local muscles and up-regulated AQP2 expression, decreasing urinary output, and kidney tissues blood stasis and edema (P < 0.05). On the other hand, compared with that of the model group, those parameters of rats in salvia group were all decreasing except urine output (P < 0.05). Such result indicated that Salvia Miltiorrhiza can reduce trauma blood stasis rat content of urine AQP2 and down-regulated AQP2 expression in kidney tissue, so as to reduce the reabsorption of water by renal tubular and increase urine output. The promoting blood circulation effect of Salvia Miltiorrhizain can alleviate the degree of the damaged tissue edema and encourage urine drainage. This therapy is closely related to the effect of regulating AQP2 in kidney by salvia, so the purpose of this study by verifying "promoting blood circulation and diuresis" as the mechanism for the regulation effect of the salvia on AQP2 expression.

  20. Hypotensive effect of the hydroalcoholic extract from Jacaranda mimosaefolia leaves in rats.

    PubMed

    Nicasio, Pilar; Meckes, Mariana

    2005-02-28

    Hypothermic and cardiovascular activities of the methanol extract of Jacaranda mimosaefolia leaves were tested. To evaluate the hypotensive properties, anesthetized rats were used and temperature, blood pressure, and cardiac frequency were recorded. In addition, the in vitro effect produced by the extract on induced contraction with norepinephrine (NE) in rat aorta rings was evaluated. The extract produced a significant hypothermic effect with a maximum at 2 h, an effect which was accompanied by hypotension and low cardiac frequency, physiological conditions that were again re-established to the following 2 h. In isolated aorta preparations norepinephrine antagonistic effect was not correlated with the presence of Ca2+, pD2 for NE was modified by the extract, an effect that could explain a blockade of the adrenergic receptors.

  1. Antioxidant and Vasodilator Activity of Ugni molinae Turcz. (Murtilla) and Its Modulatory Mechanism in Hypotensive Response

    PubMed Central

    Jofré, Ignacio; Pezoa, Cesar; Scheuermann, Erick; Rosalen, Pedro Luiz; Romero, Fernando

    2016-01-01

    Hypertension is a systemic condition with high morbidity and mortality rates worldwide, which poses an increased risk for cardiovascular diseases. In this study, we demonstrated the antioxidant and vasodilator activity of Ugni molinae Turcz. (Murtilla) fruit, a berry native to Chile and proposed models to explain its modulatory mechanism in hypotensive response. Murtilla fruits were cultivated in a germplasm bank and submitted to chemical and biological analyses. The phenolic compounds gallic acid, Catechin, Quercetin-3-β-D-glucoside, Myricetin, Quercetin, and Kaempferol were identified. Murtilla extract did not generate toxic effects on human endothelial cells and had significant antioxidant activity against ROS production, lipid peroxidation, and superoxide anion production. Furthermore, it showed dose-dependent vasodilator activity in aortic rings in the presence of endothelium, whose hypotensive mechanism is partially mediated by nitric oxide synthase/guanylate cyclase and large-conductance calcium-dependent potassium channels. Murtilla fruits might potentially have beneficial effects on the management of cardiovascular diseases. PMID:27688827

  2. An Unusual Case of Post-Traumatic Headache Complicated by Intracranial Hypotension

    PubMed Central

    Siavoshi, Sara; Dougherty, Carrie; Ailani, Jessica; Yadwadkar, Kaustubh; Berkowitz, Frank

    2016-01-01

    We present a case of post-traumatic headache complicated by intracranial hypotension resulting in an acquired Chiari malformation and myelopathy with syringomyelia. This constellation of findings suggest a possible series of events that started with a traumatic cerebral spinal fluid (CSF) leak, followed by descent of the cerebellar tonsils and disruption of CSF circulation that caused spinal cord swelling and syrinx. This unusual presentation of post-traumatic headache highlights the varying presentations and the potential sequelae of intracranial hypotension. In addition, the delayed onset of upper motor neuron symptoms along with initially normal head computerized tomography scan (CT) findings, beg the question of whether or not a post-traumatic headache warrants earlier magnetic resonance imaging (MRI). PMID:28036062

  3. Hypotensive but not normotensive haemorrhage increases tryptophan hydroxylase-2 mRNA in caudal midline medulla.

    PubMed

    Brown, Heidi J; Henderson, Luke A; Keay, Kevin A

    2006-05-08

    Severe blood loss triggers shock, a precipitous hypotension and bradycardia. The integrity of (i) neurons in the vasodepressor region of the caudal midline medulla and (ii) central 5-HT neurotransmission are critical for the expression of haemorrhagic shock. This study investigated whether progressive blood loss triggers altered synthesis of 5-HT in the vasodepressor region of the caudal midline medulla by measuring changes in relative expression levels of tryptophan hydroxylase 2 (TpH 2) mRNA, the rate-limiting enzyme in the synthesis of neuronal 5-HT. Hypotensive but not normotensive haemorrhage triggered a significant increase in TpH 2 mRNA in the vasodepressor region of the caudal midline medulla, identifying an important role for 5-HT-containing caudal midline medullary neurons in haemorrhagic shock.

  4. Unexplained hypotension and exertional dyspnea in a night-cycled peritoneal dialysis patient--a rare form of icodextrin hypersensitivity.

    PubMed

    Onuigbo, Macaulay A C

    2014-01-01

    In recent years, icodextrin 7.5% has been used in PD as an alternative to glucose to achieve sustained reliable ultrafiltration (UF) and clearance without adversely increasing glucose absorption. Icodextrin is generally well tolerated. The most commonly reported adverse events are cutaneous reactions. We report a rare form of hypersensitivity to icodextrin 7.5% that was accompanied by dyspnea and symptomatic hypotension, without increased UF to account for the observed hypotension. Icodextrin produces symptomatic hypotension in up to 40% of patients by a known mechanism of increased UF and corresponding weight loss. However, it can also produce symptomatic hypotension accompanied by several other systemic symptoms in a hypersensitivity reaction. Discontinuation of the icodextrin results in prompt resolution of those symptoms. Treating nephrologists must be aware of this rare form of icodextrin hypersensitivity.

  5. Noncardiogenic Pulmonary Edema after Amlodipine Overdose without Refractory Hypotension and Bradycardia

    PubMed Central

    Hedaiaty, M.; Eizadi-Mood, N.; Sabzghabaee, A. M.

    2015-01-01

    Amlodipine overdose can be life-threatening when manifesting as noncardiogenic pulmonary edema. Treatment remains challenging. We describe a case of noncardiogenic pulmonary edema without refractory hypotension and bradycardia after ingestion of 500 milligram amlodipine with suicidal intent. Mechanical ventilation, dexamethasone, atrovent HFA (ipratropium), pulmicort inhalation, and antibiotic therapy were used for the management. Length of hospital stay was 11 days. The patient was discharged with full recovery. PMID:26075111

  6. Nitric Oxide does not Contribute to the Hypotension of Heat Stroke

    DTIC Science & Technology

    2001-03-01

    instrumented for the measurement of arterial blood pressure , electrocardiogram, and temperature at four sites. Rats were exposed to EH (ambient...temperature, 40 6 1°C) until mean arterial blood pressure (MAP) decreased to 75 mmHg, which was arbitrarily defined as the induction of heatstroke. In...environmental heating; hyperthermia; heat stress; blood pressure HEATSTROKE IS A MEDICAL EMERGENCY characterized by profound hypotension, delirium

  7. A huge ovarian mucinous cystadenoma causing virilization, preterm labor, and persistent supine hypotensive syndrome during pregnancy

    PubMed Central

    Acar, Canan; Temizkan, Osman; Ozagari, Aysim; Gozukara, Ilay; Akyol, Atif

    2016-01-01

    Mucinous cystadenoma (MC) of the ovary is an unilateral, multilocular cystic benign epithelial tumor. Supposed to be hormone responsive, MC reaches huge sizes during pregnancy. Aortocaval compression is common during pregnancy, especially when the pregnant woman is in the supine position. However, the compression recovers with a change in position. The authors report the first case of a huge mucinous cystadenoma of the ovary complicating pregnancy and causing virilization, premature labor, and persistent supine hypotensive syndrome. PMID:27547742

  8. EFFICACY OF ATOMOXETINE VERSUS MIDODRINE FOR THE TREATMENT OF ORTHOSTATIC HYPOTENSION IN AUTONOMIC FAILURE

    PubMed Central

    Ramirez, Claudia E.; Okamoto, Luis E.; Arnold, Amy C.; Gamboa, Alfredo; Diedrich, André; Choi, Leena; Raj, Satish R.; Robertson, David; Biaggioni, Italo; Shibao, Cyndya A.

    2014-01-01

    The clinical presentation of autonomic failure is orthostatic hypotension. Severely affected patients require pharmacologic treatment to prevent pre-syncopal symptoms or frank syncope. We previously reported in a proof of concept study that pediatric doses of the norepinephrine transporter blockade, atomoxetine, increases blood pressure in autonomic failure patients with residual sympathetic activity compared with placebo. Given that the sympathetic nervous system is maximally activated in the upright position, we hypothesized that atomoxetine would be superior to midodrine, a direct vasoconstrictor, in improving upright blood pressure and orthostatic hypotension-related symptoms. To test this hypothesis, we compared the effect of acute atomoxetine versus midodrine on upright systolic blood pressure and orthostatic symptom scores in 65 patients with severe autonomic failure. There were no differences in seated systolic blood pressure (95% CI= −7.3 to 7.9, P=0.94) or seated diastolic blood pressure (95% CI= −3.4 to 4.2, P=0.83) between atomoxetine and midodrine. In contrast, atomoxetine produced a greater pressor response in upright systolic blood pressure (95% CI= 0.6 to 15, P=0.03) and upright diastolic blood pressure (95% CI=-0.05 to 8.3, P=0.05), compared with midodrine. Furthermore, atomoxetine (95% CI=0.1 to 0.8, P=0.02), but not midodrine (95% CI=-0.1 to 1.0, P=0.08), improved orthostatic hypotension-related symptoms as compared with placebo. The results of our study suggest that atomoxetine could be a superior therapeutic option than midodrine for the treatment of orthostatic hypotension in autonomic failure. PMID:25185131

  9. Centrally injected histamine increases posterior hypothalamic acetylcholine release in hemorrhage-hypotensive rats.

    PubMed

    Altinbas, Burcin; Yilmaz, Mustafa S; Savci, Vahide; Jochem, Jerzy; Yalcin, Murat

    2015-01-01

    Histamine, acting centrally as a neurotransmitter, evokes a reversal of hemorrhagic hypotension in rats due to the activation of the sympathetic and the renin-angiotensin systems as well as the release of arginine vasopressin and proopiomelanocortin-derived peptides. We demonstrated previously that central nicotinic cholinergic receptors are involved in the pressor effect of histamine. The aim of the present study was to examine influences of centrally administrated histamine on acetylcholine (ACh) release at the posterior hypothalamus-a region characterized by location of histaminergic and cholinergic neurons involved in the regulation of the sympathetic activity in the cardiovascular system-in hemorrhage-hypotensive anesthetized rats. Hemodynamic and microdialysis studies were carried out in Sprague-Dawley rats. Hemorrhagic hypotension was induced by withdrawal of a volume of 1.5 ml blood/100 g body weight over a period of 10 min. Acute hemorrhage led to a severe and long-lasting decrease in mean arterial pressure (MAP), heart rate (HR), and an increase in extracellular posterior hypothalamic ACh and choline (Ch) levels by 56% and 59%, respectively. Intracerebroventricularly (i.c.v.) administered histamine (50, 100, and 200 nmol) dose- and time-dependently increased MAP and HR and caused an additional rise in extracellular posterior hypothalamic ACh and Ch levels at the most by 102%, as compared to the control saline-treated group. Histamine H1 receptor antagonist chlorpheniramine (50 nmol; i.c.v.) completely blocked histamine-evoked hemodynamic and extracellular posterior hypothalamic ACh and Ch changes, whereas H2 and H3/H4 receptor blockers ranitidine (50 nmol; i.c.v.) and thioperamide (50 nmol; i.c.v.) had no effect. In conclusion, centrally administered histamine, acting via H1 receptors, increases ACh release at the posterior hypothalamus and causes a pressor and tachycardic response in hemorrhage-hypotensive anesthetized rats.

  10. Droxidopa and Reduced Falls in a Trial of Parkinson Disease Patients With Neurogenic Orthostatic Hypotension

    PubMed Central

    Hauser, Robert A.; Heritier, Stephane; Rowse, Gerald J.; Hewitt, L. Arthur; Isaacson, Stuart H.

    2016-01-01

    Objectives Droxidopa is a prodrug of norepinephrine indicated for the treatment of orthostatic dizziness, lightheadedness, or the “feeling that you are about to black out” in adult patients with symptomatic neurogenic orthostatic hypotension caused by primary autonomic failure including Parkinson disease (PD). The objective of this study was to compare fall rates in PD patients with symptomatic neurogenic orthostatic hypotension randomized to droxidopa or placebo. Methods Study NOH306 was a 10-week, phase 3, randomized, placebo-controlled, double-blind trial of droxidopa in PD patients with symptomatic neurogenic orthostatic hypotension that included assessments of falls as a key secondary end point. In this report, the principal analysis consisted of a comparison of the rate of patient-reported falls from randomization to end of study in droxidopa versus placebo groups. Results A total of 225 patients were randomized; 222 patients were included in the safety analyses, and 197 patients provided efficacy data and were included in the falls analyses. The 92 droxidopa patients reported 308 falls, and the 105 placebo patients reported 908 falls. In the droxidopa group, the fall rate was 0.4 falls per patient-week; in the placebo group, the rate was 1.05 falls per patient-week (prespecified Wilcoxon rank sum P = 0.704; post hoc Poisson-inverse Gaussian test P = 0.014), yielding a relative risk reduction of 77% using the Poisson-inverse Gaussian model. Fall-related injuries occurred in 16.7% of droxidopa-treated patients and 26.9% of placebo-treated patients. Conclusions Treatment with droxidopa appears to reduce falls in PD patients with symptomatic neurogenic orthostatic hypotension, but this finding must be confirmed. PMID:27332626

  11. Arterial hypotension and prerenal failure in an extremely preterm infant associated with oral sildenafil.

    PubMed

    Balasubramanian, H; Strunk, T; Kohan, R

    2015-06-01

    We report significant hypotension and prerenal failure in an extremely preterm infant following two doses of oral sildenafil that warranted discontinuation of the drug and treatment with inotropes. Blood pressure and urine output normalized after 24 h of withdrawal of the oral drug. Sildenafil should be used cautiously in extremely preterm infants early in the neonatal course, where there is limited data on its efficacy and safety.

  12. Adrenergic and prostanoid mechanisms in control of cerebral blood flow in hypotensive newborn pigs

    SciTech Connect

    Armstead, W.M.; Leffler, C.W.; Busija, D.W.; Beasley, D.G.; Mirro, R. )

    1988-04-01

    The interaction between adrenergic and prostanoid mechanisms in the control of cerebral hemodynamics in the conscious, hypotensive newborn pig was investigated. Pretreatment with the selective {alpha}{sub 1}- and {alpha}{sub 2}-adrenoceptor antagonists prazosin and yohimbine, respectively, had no effect on cerebral blood flow, calculated cerebral vascular resistance, or cerebral metabolic rate either before or after hemmorrhagic hypotension. Indomethacin treatment (5 mg/kg ia) of piglets following hemorrhage caused a significant decrease in blood flow to all brain regions within 20 min. This decrease in cerebral blood flow resulted from increased cerebral vascular resistances of 54 and 177%, 20 and 40 min after treatment, respectively. Cerebral oxygen consumption was reduced from 2.42 {+-} 0.28 to 1.45 {+-} 0.28 ml{center dot}100 g{sup {minus}1} and to 1.0 {+-} 0.28 ml{center dot}100 g{sup {minus}1}{center dot}min{sup {minus}1} 20 and 40 min after indomethacin, respectively, in hemorrhaged piglets. Decreases in cerebral blood flow and metabolic rate and increases in vascular resistance on treatment with indomethacin were the same as in animals pretreated with vehicle, prazosin, or yohimbine. These data are consistent with the hypothesis that the prostanoid system contributes to the maintenance of cerebral blood flow and cerebral metabolic rate during hypotension in the newborn, as reported previously. These data do not implicate removal of sympathetic modulation by prostanoids as a mechanism for indomethacin-induced cerebral vasoconstriction in hypotensive newborn piglets.

  13. Comparing prophylactic effect of phenylephrine and ephedrine on hypotension during spinal anesthesia for hip fracture surgery

    PubMed Central

    Abbasivash, Rahman; Sane, Shahryar; Golmohammadi, Mitra; Shokuhi, Shahram; Toosi, Fereshteh Danaye

    2016-01-01

    Background: Spinal anesthesia is an accepted technique in hip fracture surgery and prevention of this complication by sympathomimetic agents is of potential clinical significance. The aim of this study is to compare the effect of prophylactic phenylephrine versus ephedrine in the prevention of hypotension during spinal anesthesia in hip fracture surgery. Materials and Methods: Ninety-two patients undergoing hip fracture surgery with the American Society of Anesthesiologists I and II were randomized to receive prophylaxis with ephedrine or phenylephrine immediately before the spinal anesthesia. Patients in the ephedrine group received an intravenous (IV) bolus of 10 mg ephedrine, and patients in the phenylephrine group received an IV bolus of 50 μg phenylephrine. We recorded mean arterial pressure (MAP), systolic and diastolic blood pressure, heart rate every 3 min in the first 10 min and then every 5 min until 30 min after spinal anesthesia, nausea and vomiting, additional vasopressor, and atropine administration. Results: The frequency of hypotension was significantly lower in MAP, systolic and diastolic pressure in group phenylephrine in 3, 6, and 9 min after spinal anesthesia (P = 0.002, P = 0.001). There were no significant differences between two groups in heart rate at different time of study. In the phenylephrine group, lower additional vasopressor was used (8.7% and 23.9%) (P = 0.04). There were no significant differences between two groups in the use of atropine (P = 0.24), nausea and vomiting. Conclusion: At the doses of ephedrine and phenylephrine administered in this trial, phenylephrine was better to prevent hypotension during hip fracture surgery with spinal anesthesia. Higher frequency of hypotension was observed in the ephedrine group. PMID:27995106

  14. Endothelial cell tetrahydrobiopterin deficiency attenuates LPS-induced vascular dysfunction and hypotension.

    PubMed

    Chuaiphichai, Surawee; Starr, Anna; Nandi, Manasi; Channon, Keith M; McNeill, Eileen

    2016-02-01

    Overproduction of nitric oxide (NO) is thought to be a key mediator of the vascular dysfunction and severe hypotension in patients with endotoxaemia and septic shock. The contribution of NO produced directly in the vasculature by endothelial cells to the hypotension seen in these conditions, vs. the broader systemic increase in NO, is unclear. To determine the specific role of endothelium derived NO in lipopolysaccharide (LPS)-induced vascular dysfunction we administered LPS to mice deficient in endothelial cell tetrahydrobiopterin (BH4), the essential co-factor for NO production by NOS enzymes. Mice deficient in endothelial BH4 production, through loss of the essential biosynthesis enzyme Gch1 (Gch1(fl/fl)Tie2cre mice) received a 24hour challenge with LPS or saline control. In vivo LPS treatment increased vascular GTP cyclohydrolase and BH4 levels in aortas, lungs and hearts, but this increase was significantly attenuated in Gch1(fl/fl)Tie2cre mice, which were also partially protected from the LPS-induced hypotension. In isometric tension studies, in vivo LPS treatment reduced the vasoconstriction response and impaired endothelium-dependent and independent vasodilatations in mesenteric arteries from wild-type mice, but not in Gch1(fl/fl)Tie2cre mesenteric arteries. Ex vivo LPS treatment decreased vasoconstriction response to phenylephrine in aortic rings from wild-type and not in Gch1(fl/fl)Tie2cre mice, even in the context of significant eNOS and iNOS upregulation. These data provide direct evidence that endothelial cell NO has a significant contribution to LPS-induced vascular dysfunction and hypotension and may provide a novel therapeutic target for the treatment of systemic inflammation and patients with septic shock.

  15. Hypotension During Hospitalization for Acute Heart Failure Is Independently Associated With 30-Day Mortality: Findings from ASCEND-HF

    PubMed Central

    Patel, Priyesh A.; Heizer, Gretchen; O’Connor, Christopher M.; Schulte, Phillip J.; Dickstein, Kenneth; Ezekowitz, Justin A.; Armstrong, Paul W.; Hasselblad, Vic; Mills, Roger M.; McMurray, John J.; Starling, Randall C.; Wilson Tang, W. H.; Califf, Robert M.; Hernandez, Adrian F.

    2015-01-01

    Background Outcomes associated with episodes of hypotension while hospitalized are not well understood. Methods and Results Using data from ASCEND-HF, we assessed factors associated with inhospital hypotension and subsequent 30-day outcomes. Patients were classified as having symptomatic or asymptomatic hypotension. Multivariable logistic regression was used to determine factors associated with in-hospital hypotension, and Cox proportional hazards models were used to assess the association between hypotension and 30-day outcomes. We also tested for treatment interaction with nesiritide on 30-day outcomes and the association between inhospital hypotension and renal function at hospital discharge. Overall, 1555/7141 (21.8%) patients had an episode of hypotension, of which 73.1% were asymptomatic and 26.9% were symptomatic. Factors strongly associated with in-hospital hypotension included randomization to nesiritide (odds ratio [OR] 1.98, 95% confidence interval [CI] 1.76–2.23; p<0.001), chronic metolazone therapy (OR 1.74, 95% CI 1.17–2.60; p<0.001), and baseline orthopnea (OR 1.31, 95% CI 1.13–1.52; p=0.001) or S3 gallop (OR 1.21, 95% CI 1.06–1.40; p=0.006). In-hospital hypotension was associated with increased hazards of 30-day mortality (hazard ratio [HR] 2.03, 95% CI 1.57–2.61; p<0.001), 30-day heart failure (HF) hospitalization or mortality (HR 1.58, 95% CI 1.34–1.86; p<0.001), and 30-day all-cause hospitalization or mortality (HR 1.40, 95% CI 1.22–1.61; p<0.001). Nesiritide had no interaction on the relationship between hypotension and 30-day outcomes (interaction p=0.874 for death, p=0.908 for death/HF hospitalization, p=0.238 death/all-cause hospitalization). Conclusions Hypotension while hospitalized for acute decompensated HF is an independent risk factor for adverse 30-day outcomes, and its occurrence highlights the need for modified treatment strategies. Clinical Trial Registration URL: http://www.clinicaltrials.gov. Unique identifier: NCT

  16. A peptide released by pepsin from kininogen domain 1 is a potent blocker of ANP-mediated diuresis-natriuresis in the rat.

    PubMed

    Croxatto, H R; Silva, R; Figueroa, X; Albertini, R; Roblero, J; Boric, M P

    1997-10-01

    A 20-amino acid peptide, KYEIKEGDCPVQSGKTWQDC (PU-D1), released by pepsin hydrolysis of LMW kininogen domain 1 was tested for its ability to antagonize the diuretic and natriuretic effect of ANP(103-125) in anesthetized rats. A single dose of 10.8 or 21.6 pmol (25 or 50 ng) PU-D1 given intravenously or into the duodenal lumen suppressed the diuresis-natriuresis induced by 209 pmol (500 ng) ANP by 43% to 59% and 69% to 96%, respectively. None of the doses tested (2.16 to 432 pmol, 5 ng to 1 microg) modified systemic blood pressure. Strikingly, a single IV dose of 10.8 pmol PU-D1 blocked the action of ANP for more than 3 hours. ANP blockade by PU-D1 was annulled completely by the bradykinin (BK) B2 receptor inhibitor Hoe 140. On a molar basis, PU-D1 is more effective than BK and kinins of 15, 16, and 18 amino acids for blocking the ANP-mediated diuresis-natriuresis. As with BK and other kinins, the inhibitory effect of Pu-D1 on ANP is obtained only within a small range of picomol doses. A single dose of 2.16 or 4.32 pmol PU-D1 or 47 pmol (50 ng) BK is ineffective against ANP if injected alone. However, when both substances are administered concomitantly at these subthreshold doses, they totally suppress ANP-induced diuresis-natriuresis. These results raise the question of whether PU-D1, released from kininogen domain 1, either alone or associated with BK, may interact with ANP in the regulation of urinary water and electrolyte excretion in physiological and pathological conditions.

  17. Eukaliuric diuresis and natriuresis in response to the KATP channel blocker U37883A: micropuncture studies on the tubular site of action.

    PubMed

    Huang, D Y; Osswald, H; Vallon, V

    1999-08-01

    1. Systemic application of U37883A, a blocker of ATP sensitive potassium (KATP) channels, elicits diuresis and natriuresis without significantly altering urinary potassium excretion. 2. To elucidate tubular sites of action upstream to the distal nephron, micropuncture experiments were performed in nephrons with superficial glomeruli of anaesthetized Munich-Wistar-Frömter rats during systemic application of U37883A (1, 5 or 15 mg kg-1 i.v.). 3. The observed eukaliuric diuresis and natriuresis in response to U37883A at 15 mg kg-1 was accompanied by an increase in early distal tubular flow rate (VED) from 10 - 18 nl min(-1) reflecting a reduction in fractional reabsorption of fluid up to this site (FR-fluid) of 13%. The latter proposed an effect on water-permeable segments such as the proximal tubule which could fully account for the observed reduction in fractional reabsorption of Na+ up to the early distal tubule (FR-Na+) of 8% and the increase in early distal tubular Na+ concentration ([Na+]ED) from 35 - 51 mM whereas [K+]ED was left unaltered. 4. In comparison, furosemide (3 mg kg-1 i.v.), which acts in the water-impermeable thick ascending limb, elicited diuresis, natriuresis and kaliuresis which were associated with a fall in FR-Na+ of 10% with no change in FR-fluid, and a rise in [Na+]ED from 42 - 117 mM and [K+]ED from 1.2 - 5.7 mM with no change in VED. 5. Direct late proximal tubular fluid collections confirmed a significant inhibition of fluid reabsorption in proximal convoluted tubule in response to systemic application of U37883A. 6. These findings suggest that the diuretic and natriuretic effect upstream to the distal tubule in response to systemic application of U37883A involves actions on water-permeable segments such as the proximal convoluted tubule.

  18. Effects of Sacubitril/Valsartan (LCZ696) on Natriuresis, Diuresis, Blood Pressures, and NT-proBNP in Salt-Sensitive Hypertension.

    PubMed

    Wang, Tzung-Dau; Tan, Ru-San; Lee, Hae-Young; Ihm, Sang-Hyun; Rhee, Moo-Yong; Tomlinson, Brian; Pal, Parasar; Yang, Fan; Hirschhorn, Elizabeth; Prescott, Margaret F; Hinder, Markus; Langenickel, Thomas H

    2017-01-01

    Salt-sensitive hypertension (SSH) is characterized by impaired sodium excretion and subnormal vasodilatory response to salt loading. Sacubitril/valsartan (LCZ696) was hypothesized to increase natriuresis and diuresis and result in superior blood pressure control compared with valsartan in Asian patients with SSH. In this randomized, double-blind, crossover study, 72 patients with SSH received sacubitril/valsartan 400 mg and valsartan 320 mg once daily for 4 weeks each. SSH was diagnosed if the mean arterial pressure increased by ≥10% when patients switched from low (50 mmol/d) to high (320 mmol/d) sodium diet. The primary outcome was cumulative 6- and 24-hour sodium excretion after first dose administration. Compared with valsartan, sacubitril/valsartan was associated with a significant increase in natriuresis (adjusted treatment difference: 24.5 mmol/6 hours, 50.3 mmol/24 hours, both P<0.001) and diuresis (adjusted treatment difference: 291.2 mL/6 hours, P<0.001; 356.4 mL/24 hours, P=0.002) on day 1, but not on day 28, and greater reductions in office and ambulatory blood pressure on day 28. Despite morning dosing of both drugs, ambulatory blood pressure reductions were more pronounced at nighttime than at daytime or the 24-hour average. Compared with valsartan, sacubitril/valsartan significantly reduced N-terminal pro B-type natriuretic peptide levels on day 28 (adjusted treatment difference: -20%; P=0.001). Sacubitril/valsartan and valsartan were safe and well tolerated with no significant changes in body weight or serum sodium and potassium levels with either treatments. In conclusion, sacubitril/valsartan compared with valsartan was associated with short-term increases in natriuresis and diuresis, superior office and ambulatory blood pressure control, and significantly reduced N-terminal pro B-type natriuretic peptide levels in Asian patients with SSH.

  19. Green coffee bean extract and its metabolites have a hypotensive effect in spontaneously hypertensive rats.

    PubMed

    Suzuki, Atsushi; Kagawa, Daiji; Ochiai, Ryuji; Tokimitsu, Ichiro; Saito, Ikuo

    2002-01-01

    The effects of a water-soluble green coffee bean extract (GCE) on blood pressure were investigated using spontaneously hypertensive rats (SHR). There was a dose-dependent reduction in blood pressure after a single ingestion (180 to 720 mg/kg, p.o.) or long-term ingestion (0.25 to 1% diet for 6 weeks) of GCE. A single oral ingestion (50 to 200 mg/kg) of 5-caffeoylquinic acid (5-CQA), the major component of GCE, dose-dependently decreased blood pressure, suggesting that 5-CQA is involved in the hypotensive effect of GCE in SHR. Because significant increases in caffeic acid (CA) or ferulic acid (FA) were detected in plasma after oral ingestion of 5-CQA in SHR, these acids (2.5, 5,10 micromol/kg) were intravenously injected into SHR under anesthesia and the carotid arterial pressure was measured. Of the two components, FA had a stronger depressor effect than CA. The depressor effect of FA (50 mg/kg, p.o.) was attenuated by the concurrent injection of atropine sulfate (5 mg/kg, s.c.), suggesting that the hypotensive effect of FA in SHR might be mediated via the muscarinic acetylcholine receptors. These findings indicate that oral ingestion of GCE or 5-CQA decreases blood pressure in SHR, and that FA, which is a metabolite of 5-CQA, is a candidate hypotensive component.

  20. Hypotensive effect of angiotensin II after AT1-receptor blockade with losartan.

    PubMed

    Matys, T; Pawlak, R; Kucharewicz, I; Chabielska, E; Buczko, W

    2000-03-01

    Recent data suggest that hypotensive effect of losartan may not be attributed solely to AT1-receptor blockade, but also to excessive AT2 or other receptors stimulation by elevated angiotensin II and its derivative peptides. Therefore in the present study we examined the effect of angiotensin II on mean blood pressure after AT -receptor blockade with losartan. Male Wistar rats were anaesthetised and received injection of either losartan (30 mg/kg, 1 ml/kg, i.v.) or saline (the same volume and route) followed by bolus injection of angiotensin II (100, 300 or 1,000 ng/kg; 1 ml/kg, i.v.) or 1-hour infusion of angiotensin II (200 ng/kg/min; 2.5 ml/kg/h, i.v.). Control animals received saline instead. Angiotensin II, given either as the injection or the infusion, caused an evident increase in mean blood pressure (p ranged from 0.05 to 0.001 depending on the experimental group). Losartan caused a rapid drop in mean blood pressure and blunted the hypertensive effect of angiotensin II (p < 0.01). Moreover, in the losartan-pretreated animals the hypotensive phase was enhanced by the infusion, but not single injection of angiotensin II, which was most evident from the 30 th minute of observation (p < 0.05 vs control). In conclusion, hypotensive effect of losartan may be amplified by simultaneous increase in angiotensin II level, the situation observed during chronic AT1-receptor blockade.

  1. Painless Bilateral Visual Loss in A 33-Year-Old Woman With Severe Arterial Hypotension.

    PubMed

    Subirà, Olaia; Muñoz, Silvia; Sánchez, Juan José; Puyalto, Paloma; Lee, Andrew G

    2017-03-16

    A 32-year-old woman experienced dizziness and headache for 5 months. She also complained of painless, progressive bilateral visual loss for several weeks. Prior to developing the initial symptoms, she had an uncomplicated pregnancy except for dizziness and systemic hypotension during the first term. Fundus examination disclosed prominent retinal arteries, as well diffuse microaneurysms, widespread intraretinal hemorrhages, and hyperemic optic discs. Brain magnetic resonance imaging revealed multiple supratentorial white matter lesions suggestive of ischemic strokes. Initially she had severe systemic hypotension (41/17 mmHg). When reassessed, blood pressure was normal in the lower limbs, but there was severe hypotension in the upper limbs. An angio-computed tomography of the supraortic trunks showed occlusion of both primitive carotid arteries, both subclavian arteries and the right axilary and humeral arteries. Based on these findings, the diagnosis of Takayasu type I arteritis with ischemic retinopathy, and cerebrovascular disease was established. Bilateral retinal panphotocoagulation and aorta ti right carotid bypass were performed because of the severity of the ischemic lesions.

  2. Design, in vitro stability, and ocular hypotensive activity of t-butalone chemical delivery systems.

    PubMed

    Reddy, I K; Vaithiyalingam, S R; Khan, M A; Bodor, N S

    2001-08-01

    The objective of this work was to synthesize two bioreversible diacyl derivatives of t-butalone (chemical delivery systems), determine their chemical and in vitro stability, and investigate their potential use as topical antiglaucoma agents. The stability of these compounds was determined in isotonic phosphate buffers (pH range 5-8) and in selected biological media, including human whole blood, rabbit and rat blood, and the anterior segment tissues of rabbit. The ocular hypotensive activity of these compounds in unrestrained, normotensive albino rabbits was determined with a pneumatonometer. The two compounds were stable at lower pH. The stability decreased as the pH increased, suggesting their lability to base-catalyzed hydrolysis. These compounds exhibited significant differences in the hydrolytic rates in the whole blood among species examined (rat > rabbit > human). The observed rates of disappearance in different ocular tissues were indicative of relative enzyme activity in these media (iris-ciliary body > cornea > aqueous humor). The two compounds exhibited a significant ocular hypotensive activity (P < 0.01) at 2% dose level. The peak activity was found between 2 and 4 h, and the activity was maintained for 4.5 to 7 h. The dipivalyl derivative of t-butalone exhibited more pronounced decrease in intraocular pressure than that of diisovaleryl derivative. The present study suggests the possible use of diacyl derivatives of t-butalone as ocular hypotensive agents.

  3. Effect of hypotension and hyperosmolality on vasopressin and ACTH responses to hypoglycemia in conscious dogs.

    PubMed

    Raff, H; Papanek, P E; Cowley, A W

    1992-08-01

    The purpose of these studies was, first, to determine whether hypertonic saline (HS) infusion or nitroprusside (NiPr)-induced hypotension augments the vasopressin (AVP) and adrenocorticotropic hormone (ACTH) responses to insulin (Ins)-induced hypoglycemia and, second, to determine whether neurohypophysectomy could attenuate the augmentation. Conscious, male dogs (n = 8) underwent two different types of experiments. In the first, Ins was preceded by either a 30-min infusion of normal saline (control) or HS to raise plasma osmolality and AVP. HS augmented the AVP response but diminished the ACTH response to Ins. In the second group of experiments, Ins was preceded by a controlled decrease in mean arterial pressure using NiPr, which led to an increase in AVP and ACTH. The initial ACTH and AVP response to Ins was augmented by NiPr, but this early augmentation was not sustained. Neurohypophysectomy attenuated the early augmentation of the ACTH response to Ins by NiPr, but did not alter the final ACTH level achieved. We conclude that HS augmented the AVP but inhibited the ACTH response to Ins probably because of expansion of plasma volume. Concomitant hypotension led to an augmentation of the early but not sustained AVP and ACTH response to Ins. Neurohypophysectomy eliminated this augmentation, suggesting a role for AVP from the neural lobe in the early ACTH response to combined hypotension and Ins-induced hypoglycemia.

  4. Similar hypotensive responses to resistance exercise with and without blood flow restriction

    PubMed Central

    Moriggi, R; Mauro, HS Di; Dias, SC; Matos, JM; Camarço, NF; Neto, IV Sousa; Nascimento, DC; Tibana, RA; Assumpção, CO; Prestes, J; Urtado, CB

    2015-01-01

    Low intensity resistance exercise (RE) with blood flow restriction (BFR) has gained attention in the literature due to the beneficial effects on functional and morphological variables, similar to those observed during traditional RE without BFR, while the effects of BFR on post-exercise hypotension remain unclear. The aim of the present study was to compare the blood pressure (BP) response of trained normotensive individuals to RE with and without BFR. In this cross-over randomized trial, eight male subjects (23.8 ± 4 years, 74 ± 3 kg, 174 ± 4 cm) completed two exercise protocols: traditional RE (3 x 10 repetitions at 70% one-repetition maximum [1-RM]) and low intensity RE (3 x 15 repetitions at 20% 1-RM) with BFR. Blood pressure measurements were performed after 15 min of seated rest (0), immediately after and 10 min, 20 min, 30 min, 40 min, 50 min and 60 min after the experimental sessions. Similar hypotensive effects for systolic BP (SBP) were observed for both protocols (P < 0.05) after exercise, with no differences between groups (P > 0.05) and no statistically significant difference for diastolic BP (P > 0.05). These results suggest that in normotensive trained individuals, both traditional RE and RE with BFR induce hypotension for SBP, which is important to prevent cardiovascular disturbances. PMID:26681830

  5. Enalapril and atenolol in essential hypertension: attenuation of hypotensive effects in combination.

    PubMed

    Wing, L M; Chalmers, J P; West, M J; Russell, A E; Morris, M J; Cain, M D; Bune, A J; Southgate, D O

    1988-01-01

    In 16 patients with essential hypertension the effects of enalapril 20 mg once daily were compared with those of atenolol 50 mg once daily, with the two drugs in combination and with placebo using a double-blind cross-over design with allocation of treatment order by randomised Latin squares. For each patient there were four treatment phases, each of four weeks duration, which together comprised a 2 x 2 factorial experiment. All blood pressure parameters were reduced in the three active treatment phases compared to placebo (p less than 0.001). Supine blood pressures (group means) were 171/97 (placebo), 147/85 (enalapril), 154/84 (atenolol) and 144/78 (enalapril plus atenolol) (S.E.M. +/- 2/+/- 1-ANOVA), and standing blood pressures were 170/105 (placebo), 146/92 (enalapril), 154/92 (atenolol) and 147/86 (enalapril plus atenolol) (S.E.M. +/- 3/+/- 1). In the combination phase there was an additional hypotensive response but the potential fully additive effects of the two agents were attenuated by 30-50%. The mechanism of the attenuated hypotensive effect of the combined agents has not been determined. Plasma atrial natriuretic peptide (ANP) concentration was doubled in the presence of atenolol (P less than 0.01) suggesting that ANP may contribute to the hypotensive effect of the beta-blocker.

  6. 2-bromoethylamine, a suicide inhibitor of semicarbazide-sensitive amine oxidase, increases hydralazine hypotension in rats.

    PubMed

    Vidrio, Horacio; Medina, Martha

    2005-09-01

    Previous work has shown that inhibitors of the predominantly vascular enzyme semicarbazide-sensitive amine oxidase (SSAO) potentiate the hypotensive response to hydralazine, itself a SSAO inhibitor, in anesthetized rats. The present study was carried out to determine whether the recently described suicide SSAO inhibitor 2-bromoethylamine shares this effect. Hypotensive responses to hydralazine, 0.1 mg/kg IV, were obtained in chloralose-urethane-anesthetized rats, either unpretreated or receiving bromoethylamine at different doses and pretreatment intervals. Parallel experiments were run with semicarbazide, the prototypical hydrazine SSAO inhibitor. Both inhibitors potentiated hydralazine hypotension, bromoethylamine having a longer latency and a shorter duration of action than semicarbazide. High doses of bromoethylamine did not produce potentiation, a phenomenon attributed to SSAO inactivation by excess substrate and decreased formation by the enzyme of the inhibitor product. Experiments with combined administration of both inhibitors were also carried out. When semicarbazide was administered before bromoethylamine, potentiaton was prevented, apparently by a mechanism similar to the above; when it was given after the amine, potentiation was increased. This was attributed to enzyme inhibition by interaction with 2 different active sites. The charactertistics of hydralazine potentiation by bromoethylamine were considered compatible with the mechanism of SSAO inhibition by the amine.

  7. Use of an Impedance Threshold Device in Spontaneously Breathing Patients with Hypotension Secondary to Trauma: An Observational Cohort Feasibility Study

    DTIC Science & Technology

    2014-09-09

    hypotension due to multiple causes; the patients of primary interest experienced a traumatic injury. Upon determination of hypotension (systolic blood ...subjects treated, 29 (3 were excluded because of incomplete data sets and 3 patients treated with the ITDwere excluded because their blood pressure did not...and MAP as well as systolic and diastolic blood pressurewere improved. The patientswere not overresuscitatedwith this intervention.On the basis of

  8. N(G)-nitro-L-arginine methyl ester, but not methylene blue, attenuates anaphylactic hypotension in anesthetized mice.

    PubMed

    Takano, Hiromichi; Liu, Wei; Zhao, Zhansheng; Cui, Sen; Zhang, Wei; Shibamoto, Toshishige

    2007-07-01

    To clarify the role of NO in mouse anaphylactic hypotension, effects of a nitric oxide (NO) synthase inhibitor, N(G)-nitro-L-arginine methyl ester (L-NAME), on antigen-induced hypotension and portal hypertension were determined in anesthetized BALB/c mice. Systemic arterial pressure (Psa), central venous pressure (Pcv), and portal venous pressure (Ppv) were directly and simultaneously measured. Mice were first sensitized with ovalbumin, and then the injection of antigen was used to decrease Psa and increase Ppv. Pretreatment with L-NAME (1 mg/kg) attenuated this antigen-induced systemic hypotension, but not the increase in Ppv. The effect of inhibitors of soluble guanylate cyclase on anaphylactic hypotension were studied with either methylene blue (3.0 mg/kg) or 1H-[1,2,4]oxadiazole[4,3-a]quinoxalin-1-one (10 mg/kg). Neither modulated any antigen-induced changes. Furthermore, methylene blue did not improve systemic hypotension induced by Compound 48/80 (4.5 mg/kg), a mast cell degranulator, which can produce non-immunological anaphylactoid reactions. These data show in anesthetized BALB/c mice that L-NAME attenuated anaphylactic hypotension without affecting portal hypertension. This beneficial effect of L-NAME appears not to depend on the soluble guanylate cyclase pathway.

  9. Documentation and Treatment of Intraoperative Hypotension: Electronic Anesthesia Records versus Paper Anesthesia Records.

    PubMed

    Shear, Torin D; Deshur, Mark; Lapin, Brittany; Greenberg, Steven B; Murphy, Glenn S; Szokol, Joseph; Ujiki, Michael; Newmark, Rebecca; Benson, Jessica; Koress, Cody; Dwyer, Connor; Vender, Jeffery

    2017-05-01

    In this study, we examined anesthetic records before and after the implementation of an electronic anesthetic record documentation (AIMS) in a single surgical population. The purpose of this study was to identify any inconsistencies in anesthetic care based on handwritten documentation (paper) or AIMS. We hypothesized that the type of anesthetic record (paper or AIMS) would lead to differences in the documentation and management of hypotension. Consecutive patients who underwent esophageal surgery between 2009 and 2014 by a single surgeon were eligible for the study. Patients were grouped in to 'paper' or 'AIMS' based on the type of anesthetic record identified in the chart. Pertinent patient identifiers were removed and data collated after collection. Predetermined preoperative and intraoperative data variables were reviewed. Consecutive esophageal surgery patients (N = 189) between 2009 and 2014 were evaluated. 92 patients had an anesthetic record documented on paper and 97 using AIMS. The median number of unique blood pressure recordings was lower in the AIMS group (median (Q1,Q3) AIMS 30.0 (24.0, 39.0) vs. Paper 35.0 (28.5, 43.5), p < 0.01). However, the median number of hypotensive events (HTEs) was higher in the AIMS group (median (Q1,Q3) 8.0 (4.0, 18.0) vs. 4.0 (1.0, 10.5), p < 0.001), and the percentage of HTEs per blood pressure recording was higher in the AIMS group (30.4 ((Q1, Q3) (9.5, 60.9)% vs. 12.5 (2.4, 27.5)%), p < 0.01). Multivariable regression analysis identified independent predictors of HTEs. The incidence of HTEs was found to increase with AIMS (IRR = 1.88, p < 0.01). Preoperative systolic blood pressure, increased blood loss, and phenylephrine. A phenylephrine infusion was negatively associated with hypotensive events (IRR = 0.99, p = 0.03). We noted an increased incidence of HTEs associated with the institution of an AIMS. Despite this increase, no change in medical therapy for hypotension was seen. AIMS did not appear to

  10. GR-127935-sensitive mechanism mediating hypotension in anesthetized rats: are 5-HT5B receptors involved?

    PubMed

    Sánchez-Maldonado, Carolina; López-Sánchez, Pedro; Anguiano-Robledo, Liliana; Leopoldo, Marcello; Lacivita, Enza; Terrón, José A

    2015-04-01

    The 5-HT1B/1D receptor antagonist, GR-127935, inhibits hypotensive responses produced by the 5-HT1A, 5-HT1B/1D and 5-HT7 receptor agonist, and 5-HT5A/5B receptor ligand, 5-carboxamidotryptamine (5-CT), in rats. This work further characterized the above mechanism using more selective 5-HT1B and 5-HT1D receptor antagonists. Also, expression of 5-HT5A and 5-HT5B receptor mRNAs in blood vessels was searched by reverse transcription polymerase chain reaction. Decreases in diastolic blood pressure induced by 5-CT (0.001-10 μg/kg, intravenously) were analyzed in anesthetized rats that had received intravenous vehicle (1 mL/kg), SB-224289 (5-HT1B antagonist; 0.3 and 1.0 mg/kg), BRL15572 (5-HT1D antagonist; 0.3 and 1.0 mg/kg), SB-224289 + BRL15572 (0.3 mg/kg, each), or SB-224289 + BRL15572 (0.3 mg/kg, each) + GR-127935 (1 mg/kg). Because only the latter treatment inhibited 5-CT-induced hypotension, suggestive of a mechanism unrelated to 5-HT1B/1D receptors, the effects of antagonists/ligands at 5-HT5A (SB-699551, 1 mg/kg), 5-HT6 (SB-399885, 1 mg/kg), and 5-HT1B/1D/5A/5B/7 receptors (ergotamine, 0.1 mg/kg) on 5-CT-induced hypotension were tested. Interestingly, only ergotamine blocked 5-CT-induced responses; this effect closely paralleled that of SB-224289 + BRL-15572 + GR-127935. Neither did ergotamine nor GR-127935 inhibit hypotensive responses induced by the 5-HT7 receptor agonist, LP-44. Faint but clear bands corresponding to 5-HT5A and 5-HT5B receptor mRNAs in aorta and mesenteric arteries were detected. Results suggest that the GR-127935-sensitive mechanism mediating hypotension in rats is unrelated to 5-HT1B, 5-HT1D, 5-HT5A, 5-HT6, and 5-HT7 receptors. This mechanism, however, resembles putative 5-HT5B receptors.

  11. Pharmacological Evidence of α2-Adrenergic Receptors in the Hypotensive Effect of Platonia insignis Mart.

    PubMed Central

    Mendes, Marcelo Bezerra; da Silva-Filho, José Couras; Sabino, Carla Kelly Barroso; Arcanjo, Daniel Dias Rufino; Sousa, Cleyton Marcos Melo; Costa, Isabella Cristhina Gonçalves; Chaves, Mariana Helena; Oliveira, Rita de Cássia Meneses

    2014-01-01

    Abstract Platonia insignis Mart. (Clusiaceae) is a medicinal plant from the Brazilian Amazon region. The present study evaluated the biological potential of the ethanol extract (Pi-EtOH) and ethyl acetate fraction (Pi-EtOAc) of the P. insignis fruit shells on the cardiovascular system of rats. Pi-EtOH or Pi-EtOAc (12.5, 25, and 50 mg/kg) was administered intravenously in normotensive rats (260–300 g), and the mean arterial pressure and the heart rate were monitored. The Pi-EtOH induced hypotension (−11.56±0.89, −7.43±0.85, and −17.56±1.97 mmHg) followed by bradycardia in two highest doses (−8.89±3.62 and −15.79±1.83 beats/min) and Pi-EtOAc, at the same doses, induced hypotension (−11.2±1.03, −14.48±1.13, −29.89±2.67 mmHg) more intensively, followed by tachycardia at the dose 12.5 and 25 mg/kg (15.64±2.06, 19.31±1.92 beats/min) and bradycardia at a dose of 50 mg/kg (−9.98±7.33 beats/min). The hypotensive response from Pi-EtOAc was not attenuated when used in the pretreatment with L-NAME, verapamil, propranolol, and hexamethonium. However, when using yohimbine, the hypotensive effect was inhibited (−4.42±1.28 (P<.05), −3.29±0.99 (P<.05), 2.06±1.18 mmHg (P<.05); Student's t-test). Hence, the Pi-EtOAc seems to act similarly to the α2-adrenergic agonist in this hypotensive effect. PMID:25055183

  12. Lower limb-localized vascular phenomena explain initial orthostatic hypotension upon standing from squat.

    PubMed

    Tschakovsky, Michael E; Matusiak, Kristine; Vipond, Catherine; McVicar, Lisa

    2011-11-01

    The cause(s) of initial orthostatic hypotension (transient fall in blood pressure within 15 s upon active rising) have not been established. We tested the hypothesis that this hypotension is due to local vascular phenomena in contracting leg muscles from the brief effort of standing up. Seventeen young healthy subjects (2 male and 15 female, 22.5 ± 1.0 years) performed an active rise from resting squat after a 10-s squat, a 1-min squat, or a 5-min squat. Beat-by-beat arterial blood pressure, cardiac output, heart rate, and stroke volume (Finometer finger photoplethysmography) and right common femoral artery blood flow (Doppler and Echo ultrasound) were recorded. Data are means ± SE. Quiet standing before squat represented baseline. Peak increases in lower limb and total vascular conductance (ml·min(-1)·mmHg(-1)) upon standing were not different within squat conditions (10-s squat, 50.0 ± 12.4 vs. 44.3 ± 5.0; 1-min squat, 54.7 ± 9.2 vs. 50.5 ± 4.5; 5-min squat, 67.4 ± 13.7 vs. 58.8 ± 3.9; all P > 0.574). Mean arterial blood pressure (in mmHg) fell to a nadir well below standing baseline in all conditions despite increases in cardiac output. The hypotension predicted by the increase in leg vascular conductance accounted for this hypotension [observed vs. predicted (in mmHg): 10-s squat, -17.1 ± 2.1 vs. -18.3 ± 5.5; 1-min squat, -22.0 ± 3.8 vs. -25.3 ± 4.9; 5-min squat, -28.3 ± 4.0 vs. -29.2 ± 6.7]. We conclude that rapid contraction induced dilation in leg muscles with the effort of standing, along with a minor potential contribution of elevated lower limb arterio-venous pressure gradient, outstrips compensatory cardiac output responses and is the cause of initial orthostatic hypotension upon standing from squat.

  13. Keynote Address: Rev. Mark Massa

    ERIC Educational Resources Information Center

    Massa, Mark S.

    2011-01-01

    Rev. Mark S. Massa, S.J., is the dean and professor of Church history at the School of Theology and Ministry at Boston College. He was invited to give a keynote to begin the third Catholic Higher Education Collaborative Conference (CHEC), cosponsored by Boston College and Fordham University. Fr. Massa's address posed critical questions about…

  14. Early-Modern "Speech" Marks

    ERIC Educational Resources Information Center

    Blackburn, Nick

    2011-01-01

    This essay presents a revised history of the punctuation mark ["], drawn from the earliest communities who made it their own. By situating the development of ["] in its historical context, from first uses of the diple [diple] by the Greek scholar Aristarchus, it explains how it was the general applications which persisted into the sixteenth…

  15. EP Profiles Inventor Mark Sherron

    ERIC Educational Resources Information Center

    Williams, John M.

    2006-01-01

    This article profiles Mark Jerome Sherron, inventor of the ALLIES Line of electronic sensors for blind and visually-impaired people. Featuring the American Liquid Level Indicator electronic sensor (ALLI), Sherron's ALLIES product line also includes the Light Intensity Level Indicator (LILI), a multi-function electronic light sensor for electronic…

  16. Evidence for the involvement of central I1 imidazoline receptor in ethanol counteraction of clonidine hypotension in spontaneously hypertensive rats.

    PubMed

    El-Mas, M M; Abdel-Rahman, A A

    2001-09-01

    Our previous studies have shown that ethanol counteracts centrally mediated hypotensive responses to clonidine. In this study, we investigated the relative roles of central alpha2-adrenergic and I1 imidazoline receptors in the antagonistic ethanol-clonidine hemodynamic interaction. The effects of selective blockade of alpha2- or I1 receptor by 2-methoxyidazoxan and efaroxan, respectively, on the blood pressure and heart rate responses to clonidine and subsequent ethanol administration were evaluated in conscious spontaneously hypertensive rats. Intracisternal administration of clonidine (1.5 microg/kg) produced significant (30 mm Hg; p < 0.05) and sustained (at least 60 min) decreases in blood pressure and heart rate. Systemic ethanol (1 g/kg), administered 10 min after clonidine, counteracted the hypotensive response and restored blood pressure to the preclonidine levels. Treatment with 2-methoxyidazoxan (0.16 microg/kg, intracisternal) or efaroxan (0.45 microg/kg, intracisternal) produced similar attenuation of the hypotensive and bradycardic responses to clonidine. The ability of ethanol to counteract the hypotensive action of clonidine was significantly (p < 0.05) attenuated in rats pretreated with efaroxan. The pressor response to ethanol lasted only 10 min compared with at least 60 min in the absence of efaroxan. In contrast, ethanol counteraction of clonidine-evoked hypotension was not altered when alpha2-adrenoceptors were blocked by 2-methoxyidazoxan. These findings suggest that centrally mediated hypotensive and bradycardic effects of clonidine in conscious spontaneously hypertensive rats involve activation of both alpha2-adrenergic and I1 imidazoline receptors. Furthermore, the findings suggest the dependence of a fully expressed ethanol counteraction of the hypotensive action of clonidine on functional I1 receptor within the central nervous system.

  17. Early blood pressure, anti-hypotensive therapy and outcomes at 18 to 22 month corrected age in extremely preterm infants

    PubMed Central

    Batton, Beau; Li, Lei; Newman, Nancy S.; Das, Abhik; Watterberg, Kristi L.; Yoder, Bradley A.; Faix, Roger G.; Laughon, Matthew M.; Stoll, Barbara J.; Higgins, Rosemary D.; Walsh, Michele C.

    2016-01-01

    Objective Investigate relationships between early blood pressure (BP) changes, receipt of anti-hypotensive therapy, and 18 – 22 month corrected age (CA) outcomes for extremely preterm infants. Design Prospective observational study of infants 230/7 – 266/7 weeks gestational age (GA). Hourly BP values and anti-hypotensive therapy exposure in the first 24 hours were recorded. Four groups were defined: infants who did or did not receive anti-hypotensive therapy in whom BP did or did not rise at the expected rate (defined as an increase in the mean arterial BP of ≥5 mmHg/day). Random-intercept logistic modeling controlling for center clustering, GA, and illness severity was used to investigate the relationship between BP, anti-hypotensive therapies, and infant outcomes. Setting Sixteen academic centers of the Eunice Kennedy Shriver National Institute of Child Health and Human Development Neonatal Research Network. Main Outcome Measures Death or neurodevelopmental impairment / developmental delay (NIDD) at 18 – 22 months CA. Results Of 367 infants, 203 (55%) received an anti-hypotensive therapy, 272 (74%) survived to discharge, and 331 (90%) had a known outcome at 18 – 22 months CA. With logistic regression, there was an increased risk of death/NIDD with anti-hypotensive therapy versus no treatment (odds ratio: 1.836, 95% confidence interval: 1.092 – 3.086), but not NIDD alone (odds ratio: 1.53, 95% confidence interval: 0.708 – 3.307). Conclusion Independent of early BP changes, anti-hypotensive therapy exposure was associated with an increased risk of death/NIDD at 18 to 22 months CA when controlling for risk factors known to affect survival and neurodevelopment. PMID:26567120

  18. Effect of different phenylephrine bolus doses for treatment of hypotension during spinal anaesthesia in patients undergoing elective caesarean section.

    PubMed

    Mohta, M; Harisinghani, P; Sethi, A K; Agarwal, D

    2015-01-01

    The efficacy of phenylephrine might be improved by giving doses higher than that traditionally used (100 µg). This study compared the effects of three initial bolus doses of intravenous phenylephrine; 100 µg (group P100), 125 µg (group P125) and 150 µg (group P150), for the treatment of post-spinal hypotension in patients undergoing elective caesarean delivery. If hypotension was not corrected by this dose, additional boluses of 25 µg were given every minute. Further hypotensive episodes were treated with half the initial bolus dose, followed by 25 µg boluses, as required. Umbilical arterial and venous blood samples were obtained for blood gas analysis and Apgar scores recorded. One hundred and twenty subjects (40 per group) who developed post-spinal hypotension (75%) were included in this randomised, double blind trial. Although systolic blood pressure was higher at certain time-points after 150 µg phenylephrine, there were no statistically significant differences in the effectiveness of the first bolus of phenylephrine to treat hypotension (85%, 95% and 95% in groups P100, P125 and P150, respectively, P=0.215); the additional dose of phenylephrine after the first bolus (P=0.810); the number of additional boluses (P=0.318) or of hypotensive episodes (P=0.118). There were no significant differences in the number of patients developing reactive hypertension or bradycardia, in maternal side-effects or in neonatal outcomes. Although the study may have been underpowered, initial phenylephrine bolus doses of 100 µg, 125 µg and 150 µg did not significantly differ in efficacy to treat post-spinal hypotension in these patients.

  19. NG-methyl-L-arginine inhibits tumor necrosis factor-induced hypotension: implications for the involvement of nitric oxide.

    PubMed Central

    Kilbourn, R G; Gross, S S; Jubran, A; Adams, J; Griffith, O W; Levi, R; Lodato, R F

    1990-01-01

    Clinical assessment of the activity of tumor necrosis factor (TNF) against human cancer has been limited by a dose-dependent cardiovascular toxicity, most frequently hypotension. TNF is also thought to mediate the vascular collapse resulting from bacterial endotoxin. The present studies address the mechanism by which TNF causes hypotension and provide evidence for elevated production of nitric oxide, a potent vasodilator initially characterized as endothelium-derived relaxing factor. Nitric oxide is synthesized by several cell types, including endothelial cells and macrophages, from the guanidino nitrogen of L-arginine; the enzymatic pathway is competitively inhibited by NG-methyl-L-arginine. We found that hypotension induced in pentobarbital-anesthetized dogs by TNF (10 micrograms/kg, i.v., resulting in a fall in mean systemic arterial pressure from 124.7 +/- 7 to 62.0 +/- 22.9 mmHg; 1 mmHg = 133 Pa) was completely reversed within 2 min following administration of NG-methyl-L-arginine (4.4 mg/kg, i.v.). In contrast, NG-methyl-L-arginine failed to reverse the hypotensive response to an equivalent depressor dose of nitroglycerin, a compound that acts by forming nitric oxide by a nonenzymatic, arginine-independent mechanism. The effect of NG-methyl-L-arginine on TNF-induced hypotension was antagonized, and the hypotension restored, by administration of excess L-arginine (100 mg/kg, i.v.). Our findings suggest that excessive nitric oxide production mediates the hypotensive effect of TNF. PMID:2333306

  20. 40 CFR 761.45 - Marking formats.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... POLYCHLORINATED BIPHENYLS (PCBs) MANUFACTURING, PROCESSING, DISTRIBUTION IN COMMERCE, AND USE PROHIBITIONS Marking of PCBs and PCB Items § 761.45 Marking formats. The following formats shall be used for marking:...

  1. Laser marking of component parts

    SciTech Connect

    Gress, A.V. Jr.

    1983-01-01

    Permanent identification of components and subassemblies for traceability and historical purposes is essential for assemblies subject to long term storage. Marketing requirements run the gamut from simple functional alphanumerics for terminal or wire numbers to complex component identification involving program nomenclature, part number, manufacturer's code, serial number, data code, and lot or batch number. The wide range of opaque materials marked includes both ferrous and nonferrous materials, plastics, composites, and ceramics.

  2. Enhancement of the hypotensive effects of intrathecally injected endocannabinoids by the entourage compound palmitoylethanolamide.

    PubMed

    García, María del Carmen; Adler-Graschinsky, Edda; Celuch, Stella Maris

    2009-05-21

    The intrathecal (i.t.) injection of 50 and 100 nmol anandamide to urethane anesthetized rats induced a dose-dependent decrease in the mean blood pressure (-10.6+/-1.6 mmHg and -15.0+/-1.7 mmHg, respectively; n=6) whereas a lower dose of this endocannabinoid (25 nmol) was devoid of effect. Similar responses were obtained both with the non-metabolizable analog methanandamide and with the endocannabinoid N-arachidonoyldopamine. When the sub-effective dose (25 nmol) of each compound was co-injected with palmitoylethanolamide (100 nmol), significant decreases in the blood pressure were observed (-12.3+1.3 mmHg for anandamide; -12.1+/-0.8 mmHg for methanandamide; -12.1+/-0.8 mmHg for N-arachidonoyldopamine; n=4-6). Palmitoylethanolamide also enhanced the hypotensive responses to the 50 nmol-dose of both anandamide and methanandamide. The hypotensive response induced by co-administration of palmitoylethanolamide and 25 nmol anandamide was prevented both by the cannabinoid CB(1) receptor antagonist SR 144716A (20 nmol; i.t.) and by the vanilloid TRPV1 receptor antagonist capsazepine (20 nmol; i.t.) and enhanced by pretreatment with URB602 (3.5 nmol; i.t.), a putative inhibitor of palmitoylethanolamide degradation. These results suggest that in the spinal cord palmitoylethanolamide acts as an entourage compound for the hypotensive effects of i.t. administered endocannabinoids. The facilitative action of palmitoylethanolamide affects the vanilloid TRPV1 as well as the cannabinoid CB(1) receptor-mediated effects of endocannabinoids on the blood pressure control.

  3. Role of physical countermaneuvers in the management of orthostatic hypotension: efficacy and biofeedback augmentation

    NASA Technical Reports Server (NTRS)

    Bouvette, C. M.; McPhee, B. R.; Opfer-Gehrking, T. L.; Low, P. A.

    1996-01-01

    OBJECTIVE: To evaluate the efficacy of various physical countermaneuvers in reducing orthostatic hypotension and its associated symptoms and to assess the efficacy of biofeedback training in enhancing the effectiveness of physical countermaneuvers. MATERIAL AND METHODS: In nine study subjects with neurogenic orthostatic hypotension, four training sessions on physical countermaneuvers were performed after tilt-up, three with visual feedback on the effect of physical countermaneuvers on blood pressure and other cardiovascular variables. Blood pressure change and orthostatic symptoms during tilt-up were determined, as were the changes in total peripheral resistance, stroke index, and heart rate. RESULTS: The five female and four male patients had a mean age of 53 years and a mean duration of symptoms of 4.2 years. On an orthostatic symptom scale of 0 to 10, these patients had a mean symptom score of 7.3. The increment in systolic blood pressure was better for some maneuvers (such as leg crossing and a combination) than others (such as neck flexion and abdominal contraction). Three patterns of responses to biofeedback were found. Simple maneuvers such as squatting did not improve with training; visual feedback was needed for maneuvers such as thigh contraction, and performance declined without biofeedback; the third pattern, seen in maneuvers such as leg crossing, showed continued improvement with training, even without biofeedback. A survey at 3 to 4 months after training revealed continued use of physical maneuvers (3.8 +/- 3.1 per day), increased standing time with each episode of presyncopal symptoms (8.3 +/- 5.8 minutes), and continued global symptomatic improvement. Total peripheral resistance, but not heart rate or stroke index, showed significant regression with blood pressure improvement. CONCLUSION: Physical countermaneuvers are efficacious in reducing orthostatic hypotension, can be augmented by use of biofeedback, and may significantly improve the

  4. Population pharmacokinetics and haemodynamic effects of norepinephrine in hypotensive critically ill children

    PubMed Central

    Oualha, Mehdi; Tréluyer, Jean-Marc; Lesage, Fabrice; de Saint Blanquat, Laure; Dupic, Laurent; Hubert, Philippe; Spreux-Varoquaux, Odile; Urien, Saïk

    2014-01-01

    Aim The aim of the study was to investigate the pharmacokinetics and pharmacodynamics of norepinephrine in hypotensive critically ill children, including associated variability factors. Methods This was a prospective study in an 18-bed neonatal and paediatric intensive care unit. All children were aged less than 18 years, weighed more than 1500 g and required norepinephrine for systemic arterial hypotension. The pharmacokinetics and haemodynamic effects were described using the non-linear mixed effect modelling software MONOLIX. Results Norepinephrine dosing infusions ranging from 0.05 to 2 μg kg−1 min−1 were administered to 38 children whose weight ranged from 2 to 85 kg. A one compartment open model with linear elimination adequately described the norepinephrine concentration–time courses. Bodyweight (BW) was the main covariate influencing norepinephrine clearance (CL) and endogenous norepinephrine production rate (q0) via an allometric relationship: CL(BWi) = θCL × (BWi)3/4 and q0(BWi) = θq0 × (BWi)3/4. The increase in mean arterial pressure (MAP) as a function of norepinephrine concentration was well described using an Emax model. The effects of post-conceptional age (PCA) and number of organ dysfunctions were significant on basal MAP level (MAP0i = MAP0 × PCA/9i0.166) and on the maximal increase in MAP (32 mmHg and 12 mmHg for a number of organ dysfunctions ≤3 and ≥4, respectively). Conclusion The pharmacokinetics and haemodynamic effects of norepinephrine in hypotensive critically ill children highlight the between-subject variability which is related to the substantial role of age, BW and severity of illness. Taking into account these individual characteristics may help clinicians in determining an appropriate initial a priori dosing regimen. PMID:24802558

  5. Ocular hypotensive effects of a Rho-associated protein kinase inhibitor in rabbits

    PubMed Central

    Kamaruddin, Muhammad Irfan; Nakamura-Shibasaki, Momoko; Mizuno, Yu; Kiuchi, Yoshiaki

    2017-01-01

    Purpose Ripasudil is a novel Rho-associated protein kinase inhibitor that is used to treat ocular hypertension. However, the comparison of the intraocular pressure (IOP)-lowering effects between ripasudil alone and other ocular hypotensive drugs has not been studied thoroughly. The purpose of this study is to examine the ocular hypotensive effects of 0.4% ripasudil, 2% pilocarpine, 0.5% timolol and 0.1% dorzolamide in rabbits. We also studied the IOP changes when 0.4% ripasudil was combined with 2% pilocarpine, 0.5% timolol or 0.1% dorzolamide. Methods One drop of saline solution, 0.4% ripasudil, 0.5% timolol, 2% pilocarpine or 1% dorzolamide or a combination of these agents was applied topically to the left eyes of eight healthy albino rabbits. Posttreatment changes in the IOP of albino rabbits were monitored using a rebound tonometer over a 5-h time course. Changes in IOP after application of saline served as the control. One-way analysis of variance and Dunnett’s post hoc tests were used for statistical analyses. Results After topical instillation, 0.4% ripasudil resulted in significant decreases in IOP at 0.5 and 1 h compared with the control group. Treatment with timolol, pilocarpine or dorzolamide had no significant effect on IOP. Treatment with timolol, pilocarpine or dorzolamide in combination with ripasudil resulted in significant reductions in IOP at 1 h. However, none of these agents enhanced the IOP-lowering effects of ripasudil. Conclusion Ripasudil has stronger IOP-lowering effects than timolol, pilocarpine or dorzolamide hypotensive agents in our rabbit model. Addition of timolol, pilocarpine or dorzolamide did not enhance the IOP-lowering effects of ripasudil alone.

  6. Modulation of cardiac autonomic tone in non-hypotensive hypovolemia during blood donation.

    PubMed

    Yadav, Kavita; Singh, Akanksha; Jaryal, Ashok Kumar; Coshic, Poonam; Chatterjee, Kabita; Deepak, K K

    2016-08-02

    Non-hypotensive hypovolemia, observed during mild haemorrhage or blood donation leads to reflex readjustment of the cardiac autonomic tone. In the present study, the cardiac autonomic tone was quantified using heart rate and blood pressure variability during and after non-hypotensive hypovolemia of blood donation. 86 voluntary healthy male blood donors were recruited for the study (age 35 ± 9 years; weight 78 ± 12 kg; height 174 ± 6 cms). Continuous lead II ECG and beat-to-beat blood pressure was recorded before, during and after blood donation followed by offline time and frequency domain analysis of HRV and BPV. The overall heart rate variability (SDNN and total power) did not change during or after blood donation. However, there was a decrease in indices that represent the parasympathetic component (pNN50 %, SDSD and HF) while an increase was observed in sympathetic component (LF) along with an increase in sympathovagal balance (LF:HF ratio) during blood donation. These changes were sustained for the period immediately following blood donation. No fall of blood pressure was observed during the period of study. The blood pressure variability showed an increase in the SDNN, CoV and RMSSD time domain measures in the post donation period. These results suggest that mild hypovolemia produced by blood donation is non-hypotensive but is associated with significant changes in the autonomic tone. The increased blood pressure variability and heart rate changes that are seen only in the later part of donation period could be because of the progressive hypovolemia associated parasympathetic withdrawal and sympathetic activation that manifest during the course of blood donation.

  7. Comparison of Esmolol to Nitroglycerine in Controlling Hypotension During Nasal Surgery

    PubMed Central

    Guney, Ayla; Kaya, Fatma Nur; Yavascaoglu, Belgin; Gurbet, Alp; Selmi, Nazan Has; Kaya, Sener; Kutlay, Oya

    2012-01-01

    Objective: The aim of this study was to compare esmolol to nitroglycerine in terms of effectiveness in controlling hypotension during nasal surgery. Materials and Methods: After approval by our institutional Ethics Committee, 40 patients were recruited and randomized into two drug groups: esmolol (Group E) and nitroglycerine (Group N). In group E, a bolus dose of 500 μg/kg esmolol was administered over 30 sec followed by continuous administration at a dose of 25–300 μg/ kg/min to maintain systolic arterial pressure at 80 mmHg. In group N, nitroglycerine was administered at a dose of 0.5–2 μg/kg/min. Results: During the hypotensive period, systolic arterial pressure, diastolic arterial pressure, mean arterial pressure, and heart rate were decreased 24%, 33%, 27% and 35%, respectively, in group E (p<0.001, p<0.001, p<0.001, p<0.001) and were decreased 30%, 33%, 34% and 23%, respectively, in group N (p<0.001, p<0.001, p<0.001, p<0.001). The decrease in heart rate was higher in group E during the hypotensive period (p=0.048). During the recovery period, diastolic arterial pressure and heart rate were decreased 9% and 18%, respectively, in group E (p=0.044, p<0.001). Systolic arterial pressure, diastolic arterial pressure, and mean arterial pressure were decreased 7%, 3% and 7%, respectively, in group N (p=0.049, p=0.451, p=0.045). Conclusion: Esmolol provides hemodynamic stability and good surgical field visibility and should be considered as an alternative to nitroglycerine. PMID:25610218

  8. Hypotensive activity, toxicology and histopathology of opuntioside-I and methanolic extract of Opuntia dillenii.

    PubMed

    Saleem, Rubeena; Ahmad, Mohammad; Azmat, Aisha; Ahmad, Syed Iqbal; Faizi, Zareen; Abidi, Lubna; Faizi, Shaheen

    2005-10-01

    Methanolic extract of Opuntia dillenii cladodes and its pure compound alpha-pyrone glycoside, opuntioside-I showed potent hypotensive activity in normotensive rats. Both the extract and opuntioside-I showed comparable effect of 44-54% fall in Mean Arterial Blood Pressure (MABP) at the dose of 10 mg/kg. No mortality was observed in rats even at the doses of 1000 mg/kg/d and 900 mg/kg/d per oral of extract and opuntioside-I respectively. However, histopathology revealed adverse effects of high doses on liver and spleen of the experimental animals.

  9. [HFR aequilibrium can be an answer to malnutrition and hypotension in dialisys: case report].

    PubMed

    Corino, Isabella; Ria, Paolo; Pertica, Nicoletta; Zaza, Gianluigi; Lupo, Antonio

    2016-01-01

    The interdialytic hypotension is still the most frequent complication during the hemodialysis. A-HFR has dynamic profiles of ultrafiltration and conductivity of the dialysate that ensure a better refilling and reduce compliance during the dialysis treatment, furthermore reduce the amino acid loss and has a lower inflammatory effect. In our Center, we wanted to analyze the impact of this kind of dialysis on intradialytic tolerance and nutritional status in two malnourished patients with encouraging data on the use of AHFR in malnutrition and disequilibrium syndromes.

  10. Dopamine therapy does not affect cerebral autoregulation during hypotension in newborn piglets

    PubMed Central

    Hahn, Gitte Holst; Greisen, Gorm

    2017-01-01

    Background Hypotensive neonates who have been treated with dopamine have poorer neurodevelopmental outcome than those who have not been treated with dopamine. We speculate that dopamine stimulates adrenoceptors on cerebral arteries causing cerebral vasoconstriction. This vasoconstriction might lead to a rightward shift of the cerebral autoregulatory curve; consequently, infants treated with dopamine would have a higher risk of low cerebral blood flow at a blood pressure that is otherwise considered “safe”. Methods In anaesthetized piglets, perfusion of the brain, monitored with laser-doppler flowmetry, and cerebral venous saturation was measured at different levels of hypotension. Each piglet was studied in two phases: a phase with stepwise decreases in MAP and a phase with stepwise increases in MAP. We randomized the order of the two phases, whether dopamine was given in the first or second phase, and the infusion rate of dopamine (10, 25, or 40 μg/kg/min). In/deflation of a balloon catheter, placed in vena cava, induced different levels of hypotension. At each level of hypotension, fluctuations in MAP were induced by in/deflations of a balloon catheter in descending aorta. Results During measurements, PaCO2 and arterial saturation were stable. MAP levels ranged between 14 and 82 mmHg. Cerebral autoregulation (CA) capacity was calculated as the ratio between %-change in cerebrovascular resistance and %-change in MAP induced by the in/deflation of the arterial balloon. A breakpoint in CA capacity was identified at a MAP of 38±18 mmHg without dopamine and at 44±18, 31±14, and 24±14 mmHg with dopamine infusion rates of 10, 25, and 40 μg/kg/min (p = 0.057). Neither the index of steady-state cerebral perfusion nor cerebral venous saturation were affected by dopamine infusion. Conclusion Dopamine infusion tended to improve CA capacity at low blood pressures while an index of steady-state cerebral blood flow and cerebral venous saturation were unaffected by

  11. Preventing and treating orthostatic hypotension: As easy as A, B, C

    PubMed Central

    FIGUEROA, JUAN J.; BASFORD, JEFFREY R.; LOW, PHILLIP A.

    2010-01-01

    Orthostatic hypotension is a chronic, debilitating illness that is difficult to treat. The therapeutic goal is to improve postural symptoms, standing time, and function rather than to achieve upright normotension, which can lead to supine hypertension. Drug therapy alone is never adequate. Because orthostatic stress varies with circumstances during the day, a patient-oriented approach that emphasizes education and nonpharmacologic strategies is critical. We provide easy-to-remember management recommendations, using a combination of drug and non-drug treatments that have proven efficacious. PMID:20439562

  12. Morbidity and mortality of orthostatic hypotension: implications for management of cardiovascular disease.

    PubMed

    Benvenuto, Luke J; Krakoff, Lawrence R

    2011-02-01

    Orthostatic hypotension (OH) is the failure of cardiovascular reflexes to maintain blood pressure on standing from a supine or sitting position. Although OH may cause symptoms of dizziness or syncope, asymptomatic OH (AOH) is far more common and is an independent risk factor for mortality and cardiovascular disease (CVD). The prevalence of AOH increases with age, the presence of hypertension or diabetes and the use of antihypertensive or other medications. The implications of AOH for the treatment of CVD and hypertension are not well defined. This review provides an overview of the current information on this topic and recommends the more frequent assessment of OH in clinical practice and in future clinical trials.

  13. The use of antigravity suits in the treatment of idiopathic orthostatic hypotension

    NASA Technical Reports Server (NTRS)

    Landmark, K.; Kravik, S.

    1980-01-01

    Idiopathic orthostatic hypotension is an uncommon disease characterized by a drop in blood pressure when going from a recumbent to a standing position. Treatment by medication generally produces poor results. Three patients at the Royal Hospital in Oslo were treated with antigravity suits and all were able to maintain adequate blood pressures in the standing position. One patient improved dramatically and was able to take short walks while wearing the suit. The two other patients, however, felt that wearing the suits eventually became uncomfortable. This treatment represents a useful treatment alternative for intractable cases.

  14. Acute Radiation Hypotension in the Rabbit: a Model for the Human Radiation Shock Syndrome.

    NASA Astrophysics Data System (ADS)

    Makale, Milan Theodore

    This study has shown that total body irradiation (TBI) of immature (40 to 100 day old) rabbits leads to an acute fall in mean arterial pressure (MAP) 30 to 90 minutes after exposure, which takes no more than about three minutes, and often results in pressures which are less than 50% of the lowest pre-exposure MAP. This is termed acute cardiovascular collapse (ACC). ACC is often accompanied by ECG T-wave elevation, a sharp rise in ear temperature, labored breathing, pupillary constriction, bladder emptying, and loss of abdominal muscle tone. About 73% of 40 to 100 day rabbits exhibit ACC; the others and most older rabbits display gradual pressure reductions (deliberate hypotension) which may be profound, and which may be accompanied by the same changes associated with ACC. ACC and deliberate hypotension occurred in rabbits cannulated in the dorsal aorta, and in non-operated animals. The decline in MAP for all 40 to 100 day cannulated rabbits (deliberate and ACC responders) is 55.4%. The experiments described below only involved 40 to 100 day cannulated TBI rabbits. Heart region irradiation resulted in an average MAP decline of 29.1%, with 1/15 rabbits showing ACC. Heart shielding during TBI reduced the decline in MAP to 19%, with 1/10 rabbits experiencing ACC. These results imply that the heart region, which includes the heart, part of the lungs, neural receptors, roots of the systemic vessels, and the blood, is a sensitive target. Bilateral vagotomy reduced the decline in MAP to 24.9%, and abolished ACC. Atropine (6 mg/kg) reduced the frequency of ACC to 26%, and the decline in MAP to 41.4%. In 11/13 rabbits the voltage generated by left vagal transmission rose after TBI. The vagi appear to participate in radiation hypotension. Heart shielding together with bilateral vagotomy reduced the decline in MAP to only 9.9%, with no ACC responders. The mean right ventricular pressure (MRVP) rose after TBI in 8/10 rabbits. In animals which displayed either ACC or steep

  15. Postprandial Hypotension

    MedlinePlus

    ... to be retained and thus increase blood volume. Caffeine causes blood vessels to constrict. Caffeine should be taken only before breakfast so that ... and the person does not become tolerant of caffeine's effects. For people who have severe symptoms that ...

  16. 14 CFR 23.1555 - Control markings.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Control markings. 23.1555 Section 23.1555... Markings and Placards § 23.1555 Control markings. (a) Each cockpit control, other than primary flight controls and simple push button type starter switches, must be plainly marked as to its function and...

  17. 27 CFR 28.144 - Export marks.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Export marks. 28.144... § 28.144 Export marks. (a) General Requirement. In addition to the marks and brands required to be... brewer shall mark the word “Export” on each container or case of beer, or the words “Beer concentrate...

  18. 27 CFR 28.193 - Export marks.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Export marks. 28.193... Drawback Filing of Notice and Removal § 28.193 Export marks. In addition to the marks and brands required... chapter, the exporter shall mark the word “Export” on the Government side of each case or Government...

  19. 27 CFR 28.103 - Export marks.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Export marks. 28.103... Manufacturing Bonded Warehouse § 28.103 Export marks. (a) General. In addition to the marks and brands required... provisions of part 19 of this chapter, the proprietor shall mark the word “Export” on the Government side...

  20. 27 CFR 28.154 - Export marks.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Export marks. 28.154..., for Exportation or Transfer to a Foreign-Trade Zone § 28.154 Export marks. In addition to the marks... provisions of part 19 of this chapter, the proprietor shall mark the word “Export” on the Government side...

  1. A unique solar marking construct.

    PubMed

    Sofaer, A; Zinser, V; Sinclair, R M

    1979-10-19

    An assembly of stone slabs on an isolated butte in New Mexico collimates sunlight onto spiral petroglyphs carved on a cliff face. The light illuminates the spirals in a changing pattern throughout the year and marks the solstices and equinoxes with particular images. The assembly can also be used to observe lunar phenomena. It is unique in archeoastronomy in utilizing the changing height of the midday sun throughout the year rather than its rising and setting points. The construct appears to be the result of deliberate work of the Anasazi Indians, the builders of the great pueblos in the area.

  2. Carotid-cardiac baroreflex - Relaxation with orthostatic hypotension following simulated microgravity and implications for development of countermeasures

    NASA Technical Reports Server (NTRS)

    Convertino, Victor A.

    1991-01-01

    An examination has been made of the function of the human carotid-cardiac baroreflex (CCB) under the influence of simulated microgravity, varying states of vascular volume, and acute exercise. Results have been obtained which suggest that acute fluid replacement prior to reentry may not reverse the impaired baroreflex associated with postflight hypotension. It is also noted that one bout of maximal exercise increased baroreflex sensitivity and buffer capacity through 24 hrs post exercise; these baroreflex changes were the opposite of those following head-down bedrest. Contributions of reduced blood volume and impaired CCB function to orthostatic hypotension following microgravity appear to be separate and additive, so that maximal exercise and fluid replacement could be a potent countermeasure against postflight hypotension.

  3. Alkaloids in Erythrina by UPLC-ESI-MS and In Vivo Hypotensive Potential of Extractive Preparations

    PubMed Central

    Merlugo, Liara; Santos, Marí C.; Sant'Anna, Liane S.; Cordeiro, Everson W. F.; Batista, Luiz A. C.; Miotto, Silvia T. S.; Garcia, Cássia V.; Moreira, Cleci M.; Mendez, Andreas S. L.

    2015-01-01

    Erythrina species are used in popular medicine as sedative, anxiolytic, anti-inflammatory, and antihypertensive. In this work, we investigated the chemical composition of extracts obtained from leaves of E. falcata and E. crista-galli. The hypotensive potential of E. falcata and the mechanism of action were also studied. The extracts were obtained by maceration and infusion. The total content of phenolic compounds and flavonoids was estimated by spectrophotometric methods. The chemical constituents were studied performing a chromatographic analysis by UPLC-ESI-MS. For in vivo protocols, blood pressure and heart rate were measured by the invasive hemodynamic monitoring method. Different concentrations of extracts and drugs such as L-NAME, losartan, hexamethonium, and propranolol were administrated i.v. The results of total phenolic contents for E. falcata and E. crista-galli were 1.3193–1.4989 mgGAE/mL for maceration and 0.8771–0.9506 mgGAE/mL for infusion. In total flavonoids, the content was 7.7829–8.1976 mg RE/g for maceration and 9.3471–10.4765 RE mg/g for infusion. The chemical composition was based on alkaloids, suggesting the presence of erythristemine, 11β-methoxyglucoerysodine, erysothiopine, 11β-hydroxyerysodine-glucose, and 11-hydroxyerysotinone-rhamnoside. A potent dose-dependent hypotensive effect was observed for E. falcata, which may be related to the route of β-adrenergic receptors. PMID:26356581

  4. One hemodialysis patient with headache, blurred vision, and hypotension induced by pituitary prolactinoma.

    PubMed

    Dai, Wen-di; Liu, Wen-Hu; Zhang, Dong-Liang

    2012-08-01

    We reported a rare case of a dialysis patient coincident pituitary prolactinoma with calcification. A 55-year-old woman who had undergone hemodialysis for 8 years was admitted to the nephrology unit because of headache, blurred vision, and hypotension. Physical examination was normal; endocrinological examination demonstrated elevated serum levels of prolactin (> 4240 mIU/L), but other hormonal profiles, such as growth hormon, adrenocorticotropic hormone, thyroid stimulating hormone, free triiodothyronine, free thyroxine, follicle-stimulating hormone and luteinizing hormone, were absolutely or relatively lower. A cranial computed tomography (CT) suggested saddle area a high-density screenage with an anteroposterior diameter of 1.0 cm. A cerebral magnetic resonance scan confirmed the pituitary adenoma accompanied with calcification. Contrast-enhanced T1-weighted images revealed a less enhancing tumor, 14 mm wide round lesion with a high intensity signal. It enlarges the sella turcica, but the optic chiasma is not displaced. We suggest that in the differential diagnosis of any hemodialysis patient with severe headache, hypotension, and visual disturbances, this syndrome should be considered as prompt pituitary adenoma.

  5. Lisuride acts at multiple sites to induce ocular hypotension and mydriasis.

    PubMed

    Potter, D E; Ogidigben, M J; Chu, T C

    1998-11-01

    Topically unilaterally applied lisuride caused dose-related lowering of intraocular pressure in ipsilateral (treated) but not in contralateral eyes of normal rabbits. The ocular hypotensive response induced by lisuride was antagonized by pretreatment with metoclopramide, a dopamine receptor antagonist, and was partially reduced by local sympathetic denervation. In contrast to the unilateral effect on intraocular pressure, lisuride caused mydriasis in both eyes. Mydriasis was of greater magnitude and more sustained in normal eyes compared to sympathetically denervated eyes. Additional in vivo experiments demonstrated that lisuride caused dose-related suppression of neuronally initiated contractions of cat nictitating membrane. In in vitro experiments lisuride caused dose-related inhibition of norepinephrine release from isolated rabbit iris-ciliary bodies. Pretreatment with Bay K 8644, a calcium channel activator, did not attenuate lisuride-induced inhibition of norepinephrine release in isolated rabbit iris-ciliary bodies. Because lisuride pretreatment caused no change in isoproterenol-stimulated cAMP accumulation in isolated iris-ciliary bodies, suppression of adenylate cyclase was unlikely. It is concluded that the ocular hypotensive effect of lisuride results, in part, from activation of prejunctional dopaminergic receptors on peripheral sympathetic nerves in the anterior segment of the eye but may also involve antagonism on peripheral postjunctional alpha1 adrenoceptors as well. Bilateral increases in pupil diameter antagonized by metoclopramide suggest a stimulatory action of lisuride on dopamine receptors in the central nervous system.

  6. Reversible coma and Duret hemorrhage after intracranial hypotension from remote lumbar spine surgery: case report.

    PubMed

    Bonow, Robert H; Bales, James W; Morton, Ryan P; Levitt, Michael R; Zhang, Fangyi

    2016-03-01

    Intracranial hypotension is a rare condition caused by spontaneous or iatrogenic CSF leaks that alter normal CSF dynamics. Symptoms range from mild headaches to transtentorial herniation, coma, and death. Duret hemorrhages have been reported to occur in some patients with this condition and are traditionally believed to be associated with a poor neurological outcome. A 73-year-old man with a remote history of spinal fusion presented with syncope and was found to have small subdural hematomas on head CT studies. He was managed nonoperatively and discharged with a Glasgow Coma Scale score of 15, only to return 3 days later with obtundation, fixed downward gaze, anisocoria, and absent cranial nerve reflexes. A CT scan showed Duret hemorrhages and subtle enlargement of the subdural hematomas, though the hematomas remained too small to account for his poor clinical condition. Magnetic resonance imaging of the spine revealed a large lumbar pseudomeningocele in the area of prior fusion. His condition dramatically improved when he was placed in the Trendelenburg position and underwent repair of the pseudomeningocele. He was kept flat for 7 days and was ultimately discharged in good condition. On long-term follow-up, his only identifiable deficit was diplopia due to an internuclear ophthalmoplegia. Intracranial hypotension is a rare condition that can cause profound morbidity, including tonsillar herniation and brainstem hemorrhage. With proper identification and treatment of the CSF leak, patients can make functional recoveries.

  7. Phenylephrine infusion for spinal-induced hypotension in elective cesarean delivery: Does preload make a difference?

    PubMed Central

    Bottiger, Brandi A; Bezinover, Dmitri S; Mets, Berend; Dalal, Priti G; Prozesky, Jansie; Ural, Serdar; Vaida, Sonia

    2016-01-01

    Background and Aims: Patients undergoing elective cesarean delivery (CD) have a high-risk of spinal-induced hypotension (SIH). We hypothesized that a colloid preload would further reduce SIH when compared with a crystalloid preload. Material and Methods: Eighty-two healthy parturients undergoing elective CD were included in the study. Patients were randomly assigned to two groups (41 patients in each group) to receive either Lactated Ringer's solution (1500 ml) or hydroxyethyl starch (6% in normal saline, 500 ml) 30 min prior to placement of spinal anesthesia. All patients were treated with a phenylephrine infusion (100 mcg/min), titrated during the study. Results: There was no statistical difference between groups with regards to the incidence of hypotension (10.8% in the colloid group vs. 27.0% in the crystalloid group, P = 0.12). There was also no difference between groups with respect to bradycardia, APGAR scores, and nausea and vomiting. Significantly less phenylephrine (1077.5 ± 514 mcg) was used in the colloid group than the crystalloid group (1477 ± 591 mcg, P = 0.003). Conclusion: The preload with 6% of hydroxyethyl starch before CD might be beneficial for the prevention of SIH. PMID:27625478

  8. Use of Dexmedetomidine and Esmolol for Hypotension in Lumbar Spine Surgery

    PubMed Central

    Nazir, Ovais; Wani, Mushtaq Ahmad; Ali, Nadeem; Sharma, Tarun; Khatuja, Amit; Misra, Rajesh; Maqsood, Mehreen

    2016-01-01

    Background The importance of decreasing bleeding in spine surgery is not only important to maintain the patient's hemodynamic balance but also allow a better view of the surgical field. Objectives The current study aimed to compare dexmedetomidine and Esmolol™ as agents to induce hypotension in lumbar spine surgeries. Patients and Methods A total of 50 patients aged 20 to 65 years belonging to the American society of anaesthesiologist (ASA) class I - II scheduled for decompression and fixation of the lumbar spine were included and divided into two groups namely, Group I, who received Esmolol and group II, who received dexmedetomidine, intravenously. The patients were compared for intraoperative hemodynamic parameters, estimated blood loss, operation time, intraoperative analgesic (fentanyl) consumption, and total fall in haemoglobin (Hb) during the perioperative period. Results The study results showed that dexmedetomidine had lower (100.8 µg) fentanyl and sevoflurane consumption (1.2%), and less blood loss (278 mL) in comparison to the Esmolol group. Conclusions Both dexmedetomidine and Esmolol can be used as agents to control hypotension in patients undergoing lumbar spine decompression and fixation surgery; the dexmedetomidine group, however, was associated with better intraoperative hemodynamic stability and reduced intraoperative analgesic and volatile anaesthetic requirement. PMID:27921016

  9. Hemodynamic Effects of Midodrine After Space Flight in Astronauts Without Orthostatic Hypotension

    NASA Technical Reports Server (NTRS)

    Platts, Steven H.; Ziegler, Michael G.; Waters, Wendy W.; Meck, Janice V.

    2006-01-01

    Orthostatic hypotension and presyncope are common and potentially serious risks for astronauts returning from space. Susceptible subjects fail to generate an adequate adrenergic response to upright posture. The -1 adrenergic agonist, midodrine, may be an effective countermeasure. We tested the hypothesis that midodrine would have no negative hemodynamic effect on healthy astronauts returning from space. Five male astronauts participated in preflight and postflight tilt testing on a control flight as well as on the test flights, where midodrine (10 mg, orally) was administered after landing, approximately 1 hour before testing. None of these astronauts exhibited orthostatic hypotension or presyncope before or after either flight. Midodrine did not cause any untoward reactions in these subjects before or after flight, in fact a modest beneficial effect was seen on postflight tachycardia (p=0.036). These data show that midodrine protected against post-spaceflight increases in heart rate, without having any adverse hemodynamic effects on non-presyncopal, male astronauts. Among these subjects, midodrine was a safe cardiovascular countermeasure.

  10. Insignificant response of the fetal placental circulation to arterial hypotension in sheep.

    PubMed

    Faber, J J; Anderson, D F; Louey, S; Thornburg, K L; Giraud, G D

    2011-10-01

    Infusion of the angiotensin-converting enzyme inhibitor enalaprilat into fetal sheep caused a profound arterial hypotension within days. Five fetal lambs were infused with enalaprilat for 8 days starting at day 128 of gestation. Total accumulated dose was 0.30 ± 0.11 mg/kg. Arterial pressure decreased from 43.6 to 25.6 mmHg; venous pressure did not change. Biventricular output was not statistically significantly changed; placental blood flow decreased almost in proportion to the decrease in pressure but the increase in somatic flow was not statistically significant. There were no significant changes in pressure 30 min after the initial 50-μg loading dose of enalaprilat. However, the arterial pressure responses to test doses of ANG I were largely abolished. After 1 day, however, there was a significant decrease in somatic vascular resistance, which became stronger with time, but almost no decrease in the placental resistance. We conclude that the fetal somatic circulation exhibits a slow but strong decrease in resistance but that the response to hypotension is weak or absent in the fetal placenta, possibly because it is already fully relaxed.

  11. Evaluation of Hypotensive and Antihypertensive Effects of Velvet Bean (Mucuna pruriens L.) Hydrolysates.

    PubMed

    Chel-Guerrero, Luis; Galicia-Martínez, Saulo; Acevedo-Fernández, Juan José; Santaolalla-Tapia, Jesus; Betancur-Ancona, David

    2017-01-01

    Hypertension could cause significant worldwide health problems that affect 15-20% of all adults; according to National Health and Nutrition Examination Survey, about 29% of the adult population in the United States are hypertensive. Recent research has shown that peptides derived from the hydrolysis of food proteins can decrease blood pressure. This study was carried out to evaluate the hypotensive and antihypertensive potential of Mucuna pruriens protein hydrolysates in in vitro and in vivo models. M. pruriens protein concentrate was prepared by wet fractionation and enzymatically hydrolyzed using Alcalase(®), Flavourzyme(®), and the sequential system Alcalase-Flavourzyme at different times (5-120 min). The biological potential was measured in vitro based on the IC50 value as well as in vivo effect, measuring the systolic (SBP) and diastolic (DBP) blood pressure in normotensive and antihypertensive Wistar-Kyoto rats by the tail-cuff method. Hydrolysis of M. pruriens protein concentrates with commercial enzymes generated extensive hydrolysates with angiotensin-converting enzyme (ACE-I) inhibitory activity (IC50: 0.589-0.993 mg/mL) and hypotensive (SBP: 0.6-47.43%, DBP: 1.94-43.47%) and antihypertensive (SBP: 8.84-27.29% DBP: 16.1-29.37%) effect. These results indicate that Mucuna pruriens protein hydrolysate (MPPH) could be used as a functional ingredient to prevent blood pressure increase.

  12. Neurogenic orthostatic hypotension in Parkinson’s disease: evaluation, management, and emerging role of droxidopa

    PubMed Central

    Isaacson, Stuart H; Skettini, Julia

    2014-01-01

    Neurogenic orthostatic hypotension (nOH) is due to failure of the autonomic nervous system to regulate blood pressure in response to postural changes due to an inadequate release of norepinephrine, leading to orthostatic hypotension and supine hypertension. nOH is common in Parkinson’s disease (PD). Prevalence varies throughout the course of PD, ranging from 40% to 60%, and resulting in symptomatic nOH in approximately half. Symptomatic nOH, including lightheadedness, can limit daily activities and lead to falls. Symptomatic nOH can also limit therapeutic options for treating PD motor symptoms. Clinical evaluation should routinely include symptom assessment and blood pressure measurement of supine, sitting, and 3-minute standing; 24-hour ambulatory blood pressure monitoring can also be helpful. Non-pharmacological management of symptomatic nOH involves education, physical maneuvers, and adequate hydration. Current pharmacological treatment of symptomatic nOH includes salt supplement, fludrocortisone, midodrine, pyridostigmine, and other empiric medications. Despite these options, treatment of symptomatic nOH remains suboptimal, often limited by severe increases in supine blood pressure. Droxidopa, an oral prodrug converted by decarboxylation to norepinephrine, is a promising therapeutic option for symptomatic nOH in PD, improving symptoms of nOH, daily activities, falls, and standing systolic blood pressure in several recent trials. These trials demonstrated short-term efficacy and tolerability, with comparable increases in standing and supine blood pressures. Longer-term studies are ongoing to confirm durability of treatment effect. PMID:24729712

  13. Postexercise hypotension and sustained postexercise vasodilatation: what happens after we exercise?

    PubMed

    Halliwill, John R; Buck, Tahisha M; Lacewell, Alisha N; Romero, Steven A

    2013-01-01

    A single bout of aerobic exercise produces a postexercise hypotension associated with a sustained postexercise vasodilatation of the previously exercised muscle. Work over the last few years has determined key pathways for the obligatory components of postexercise hypotension and sustained postexercise vasodilatation and points the way to possible benefits that may result from these robust responses. During the exercise recovery period, the combination of centrally mediated decreases in sympathetic nerve activity with a reduced signal transduction from sympathetic nerve activation into vasoconstriction, as well as local vasodilator mechanisms, contributes to the fall in arterial blood pressure seen after exercise. Important findings from recent studies include the recognition that skeletal muscle afferents may play a primary role in postexercise resetting of the baroreflex via discrete receptor changes within the nucleus tractus solitarii and that sustained postexercise vasodilatation of the previously active skeletal muscle is primarily the result of histamine H(1) and H(2) receptor activation. Future research directions include further exploration of the potential benefits of these changes in the longer term adaptations associated with exercise training, as well as investigation of how the recovery from exercise may provide windows of opportunity for targeted interventions in patients with hypertension and diabetes.

  14. Arterial baroreflex control of sympathetic nerve activity during acute hypotension: effect of fitness

    NASA Technical Reports Server (NTRS)

    Fadel, P. J.; Stromstad, M.; Hansen, J.; Sander, M.; Horn, K.; Ogoh, S.; Smith, M. L.; Secher, N. H.; Raven, P. B.

    2001-01-01

    We examined arterial baroreflex control of muscle sympathetic nerve activity (MSNA) during abrupt decreases in mean arterial pressure (MAP) and evaluated whether endurance training alters baroreflex function. Acute hypotension was induced nonpharmacologically in 14 healthy subjects, of which 7 were of high fitness (HF) and 7 were of average fitness (AF), by releasing a unilateral arterial thigh cuff after 9 min of resting ischemia under two conditions: control, which used aortic and carotid baroreflex (ABR and CBR, respectively) deactivation; and suction, which used ABR deactivation alone. The application of neck suction to counteract changes in carotid sinus transmural pressure during cuff release significantly attenuated the MSNA response (which increased 134 +/- 32 U/14 s) compared with control (which increased 195 +/- 43 U/14 s) and caused a greater decrease in MAP (19 +/- 2 vs. 15 +/- 2 mmHg; P < 0.05). Furthermore, during both trials, the HF subjects exhibited a greater decrease in MAP compared with AF subjects despite an augmented baroreflex control of MSNA. These data indicate that the CBR contributes importantly to the MSNA response during acute systemic hypotension. Additionally, we suggest that an impaired control of vascular reactivity hinders blood pressure regulation in HF subjects.

  15. Evaluation of intravenous lipid emulsion on haloperidol-induced hypotension in rabbits.

    PubMed

    Moshiri, Mohammad; Vahabzadeh, Maryam; Mohammadpour, Amir Hooshang; Hosseinzadeh, Hossein

    2016-05-01

    There are many reports on the effects of intravenous lipid emulsion (ILE) as an antidote in drug toxicity. Haloperidol (HAL) is a butyrophenone antipsychotic agent which is highly lipophilic. Hypotension is an important adverse effect of HAL administration and overdose. The aim of this study was to investigate the beneficial hemodynamic effects of ILE on acute HAL poisoning. We used six groups of five male rabbits. Two groups received aseptic distilled water intravenously followed by infusion of 18.6 ml/kg normal saline, as negative control group, or ILE 20% after 0.5 h. The third group received 18.6 ml/kg normal saline after HAL infusion (2.6 mg/kg). The other three groups received ILE 20% solution (6, 12, and 18.6 ml/kg) following HAL (2.6 mg/kg) administration. We measured blood pressure at 0, 0.5, 1, 2, 3, 4, 8, and 24 h after starting HAL administration, from left forelimb using a noninvasive method that was carried out automatically with a neonatal intensive care unit bedside monitor. ILE 20% at the dose of 18 ml/kg could return the reduced mean arterial pressure and diastolic blood pressure sooner than the other doses and normal saline. In conclusion, ILE could reverse HAL-induced hypotension same as the other lipophilic drugs. However, the clinical use of ILE for this purpose needs more evaluation to determine its exact indication and safety.

  16. Temazepam, but not zolpidem, causes orthostatic hypotension in astronauts after spaceflight

    NASA Technical Reports Server (NTRS)

    Shi, Shang-Jin; Garcia, Kathleen M.; Meck, Janice V.

    2003-01-01

    Insomnia is a common symptom, not only in the adult population but also in many astronauts. Hypnotics, such as temazepam (a benzodiazepine) and zolpidem (an imidazopyridine), are often taken to relieve insomnia. Temazepam has been shown clinically to have hemodynamic side effects, particularly in the elderly; however, the mechanism is not clear. Zolpidem does not cause hemodynamic side effects. The purpose of this study was to determine whether the use of different hypnotics during spaceflight might contribute significantly to the high incidence of postflight orthostatic hypotension, and to compare the findings in astronauts with clinical research. Astronauts were separated into three groups: control (n = 40), temazepam (15 or 30 mg; n = 9), and zolpidem (5 or 10 mg; n = 8). In this study, temazepam and zolpidem were only taken the night before landing. The systolic and diastolic blood pressures and heart rates of the astronauts were measured during stand tests before spaceflight and on landing day. On landing day, systolic pressure decreased significantly and heart rate increased significantly in the temazepam group, but not in the control group or in the zolpidem group. Temazepam may aggravate orthostatic hypotension after spaceflight when astronauts are hemodynamically compromised. Temazepam should not be the initial choice as a sleeping aid for astronauts. These results in astronauts may help to explain the hemodynamic side effects in the elderly who are also compromised. Zolpidem may be a better choice as a sleeping aid in these populations.

  17. Refractory hypotension and edema caused by right atrial compression in a woman with polycystic kidney disease.

    PubMed

    Lasic, Lada Beara; DeVita, Maria V; Spiegel, Paul J; Marino, Nino D; Mellow, Ellen; Michelis, Michael F

    2004-03-01

    We present the case of a 60-year-old woman with a history of autosomal dominant polycystic kidney disease and long-standing hypertension who developed persistent hypotension. While in the hospital for the treatment of bacteriemia, the patient had low systolic blood pressures (90 to 100 mm Hg), which was thought to be the consequence of infection. After the infection was adequately controlled and the blood pressure did not improve, an echocardiogram was done to further elucidate her hypotension. It was nondiagnostic and revealed an ejection fraction of 70% with left ventricular hypertrophy. Shortly after discharge, she developed significant lower extremity edema and her blood pressure remained low. Due to the low blood pressure it was not possible to mobilize the fluid with her dialysis treatments. A repeat transthoracic echocardiogram at that time revealed that the right atrium was partially compressed throughout the cardiac cycle by polycystic hepatic tissue. This tissue invaginated up through the right hemidiaphragm. A partial liver resection was considered for the patient. Instead, right nephrectomy was performed and the blood pressure improved.

  18. An Abdominal CT may be Safe in Selected Hypotensive Trauma Patients with Positive FAST Exam

    PubMed Central

    Cook, Mackenzie R.; Holcomb, John B.; Rahbar, Mohammad H.; Alarcon, Louis H.; Bulger, Eileen M.; Brasel, Karen J.; Schreiber, Martin A.

    2016-01-01

    Background Positive Focused Assessment with Sonography in Trauma (FAST) and hypotension often indicates urgent surgery. An abdomen/pelvis CT (apCT) may allow less invasive management but the delay may be associated with adverse outcomes. Methods Patients in the Prospective Observational Multicenter Major Trauma Transfusion study with hypotension and a positive FAST (HF+) who underwent a CT (apCT+) were compared to those who did not. Results Of the 92 HF+ identified, 32(35%) underwent apCT during initial evaluation and apCT was associated with decreased odds of an emergency operation, OR 0.11 95% CI (0.001–0.116) and increased odds of angiographic intervention, OR 14.3 95% CI (1.5–135). There was no significant difference in 30 day mortality or need for dialysis. Conclusion An apCt in HF+ patients is associated with reduced odds of emergency surgery, but not mortality. Select HF+ patients can safely undergo apCT to obtain clinically useful information. PMID:25805456

  19. Effect of Focused Bedside Ultrasonography in Hypotensive Patients on the Clinical Decision of Emergency Physicians

    PubMed Central

    Gungor, Faruk; Guven, Ramazan; Akyol, K. Can; Kozaci, Nalan; Kesapli, Mustafa

    2017-01-01

    We assessed the effect of focused point of care ultrasound (POCUS) used for critical nontraumatic hypotensive patients presenting to the emergency department of our hospital on the clinical decisions of the physicians and whether it led to the modification of the treatment modality. This prospective clinical study was conducted at the Emergency Department of Antalya Training and Research Hospital. Nontraumatic patients aged 18 and older who presented to our emergency department and whose systolic blood pressure was <100 mmHg or shock index (heart rate/systolic blood pressure) was >1 were included in the study. While the most probable preliminary diagnosis established by the physician before POCUS was consistent with the definitive diagnosis in 60.6% (n = 109) of 180 patients included in the study, it was consistent with the definitive diagnosis in 85.0% (n = 153) of the patients after POCUS (p < 0.001). POCUS performed for critical hypotensive patients presenting to the emergency department is an appropriate diagnostic tool that can be used to enable the physicians to make the accurate preliminary diagnosis and start the appropriate treatment in a short time. PMID:28357139

  20. Effects of prolonged hemorrhagic hypotensive stress on catecholamine concentration of mesenteric blood vessels.

    PubMed

    Lombard, J H; Loegering, D J; Stekiel, W J

    1977-01-01

    Norepinephrine (NE) and epinephrine (E) concentrations were determined fluorometrically as an index of functional adrenergic innervation in small mesenteric arteries, veins, and superior mesenteric arteries of dogs and rats subjected to a period of prolonged hemorrhage at a constant mean arterial pressure of 35 mm Hg. In nonhemorrhaged animals, highest catecholamine concentrations were found in the small principal arteries, next highest in the small veins, and least in superior mesenteric arteries. A significant decrease occurred in the NE and E concentrations of all three vessel types in the dog during the decompensatory phase of the hypotensive stress (defined as the hypotensive period beyond the time at which maximum bleedout volume occurred). In the rat significant decreases were detectable only in the NE concentrations of the small arteries and veins during this phase. It is concluded that the increase in neurogenic vascular tone accompanying severe hemorrhagic stress is lost simultaneously on the arterial and venous sides of compensatory vascular beds. Such loss is closely related to transmitter depletion at the adrenergic neuromuscular junction and, if allowed to continue uncorrected, can contribute significantly to irreversible cardiovascular collapse.

  1. Preoperative ephedrine counters hypotension with propofol anesthesia during valve surgery: a dose dependent study.

    PubMed

    El-Tahan, Mohamed R

    2011-01-01

    The prophylactic use of small doses of ephedrine may counter the hypotension response to propofol anesthesia with minimal hemodynamic changes. One hundred-fifty patients scheduled for valve surgery were randomly assigned into five groups (n = 30 for each) to receive saline, 0.07, 0.1, or 0.15 mg/kg of ephedrine, or phenylephrine 1.5 μg/kg before induction of propofol-fentanyl anesthesia. After induction, patient receiving ephedrine had higher mean arterial pressure, systemic vascular resistance (SVRI), cardiac (CI), stroke volume (SVI), and left ventricular stroke work (LVSWI) indices. Patients received 0.15 mg/kg of ephedrine showed additional increased heart rate and frequent ischemic episodes (P < 0.001). However, those who received phenylephrine showed greater rise in SVRI, reduced CI, SVI, and LVSWI and more frequent ischemic episodes. We conclude that the prophylactic use of small doses of ephedrine (0.07-0.1 mg/kg) is safe and effective in the counteracting propofol-induced hypotension during anesthesia for valve surgery.

  2. Temazepam, but not zolpidem, causes orthostatic hypotension in astronauts after spaceflight.

    PubMed

    Shi, Shang-Jin; Garcia, Kathleen M; Meck, Janice V

    2003-01-01

    Insomnia is a common symptom, not only in the adult population but also in many astronauts. Hypnotics, such as temazepam (a benzodiazepine) and zolpidem (an imidazopyridine), are often taken to relieve insomnia. Temazepam has been shown clinically to have hemodynamic side effects, particularly in the elderly; however, the mechanism is not clear. Zolpidem does not cause hemodynamic side effects. The purpose of this study was to determine whether the use of different hypnotics during spaceflight might contribute significantly to the high incidence of postflight orthostatic hypotension, and to compare the findings in astronauts with clinical research. Astronauts were separated into three groups: control (n = 40), temazepam (15 or 30 mg; n = 9), and zolpidem (5 or 10 mg; n = 8). In this study, temazepam and zolpidem were only taken the night before landing. The systolic and diastolic blood pressures and heart rates of the astronauts were measured during stand tests before spaceflight and on landing day. On landing day, systolic pressure decreased significantly and heart rate increased significantly in the temazepam group, but not in the control group or in the zolpidem group. Temazepam may aggravate orthostatic hypotension after spaceflight when astronauts are hemodynamically compromised. Temazepam should not be the initial choice as a sleeping aid for astronauts. These results in astronauts may help to explain the hemodynamic side effects in the elderly who are also compromised. Zolpidem may be a better choice as a sleeping aid in these populations.

  3. Randomised controlled trial of plasma protein fraction versus dopamine in hypotensive very low birthweight infants.

    PubMed Central

    Gill, A B; Weindling, A M

    1993-01-01

    Around 20% of very low birthweight infants admitted to a neonatal intensive care unit become hypotensive within 24 hours of their admission. Standard treatment is either expansion of the circulating volume by the infusion of plasma protein fraction or by using dopamine to improve cardiac function. The purpose of this study was to investigate by a randomised controlled trial which was the most appropriate treatment. Thirty nine infants were randomised to receive either plasma protein fraction or dopamine as first line treatment if they became hypotensive within 24 hours of admission to the neonatal intensive care unit. Seventeen of 19 (89%) infants responded to dopamine, whereas only 9/20 (45%) responded to plasma protein fraction. The median dose of dopamine needed to increase the blood pressure to at least the 10th centile was 7.5 micrograms/kg/min and was infused for a median duration of 18 hours. These observations suggest that dopamine should be used earlier in the treatment of these infants than has previously been recommended. PMID:8215566

  4. Semicarbazide-sensitive amine oxidase substrates potentiate hydralazine hypotension: possible role of hydrogen peroxide.

    PubMed

    Vidrio, Horacio; Medina, Martha; González-Romo, Pilar; Lorenzana-Jiménez, Marte; Díaz-Arista, Patricia; Baeza, Alejandro

    2003-11-01

    The relation between inhibition of semicarbazide-sensitive amine oxidase (SSAO) and vasodilation by hydralazine (HYD) was evaluated in chloralose/urethane-anesthetized rats pretreated with various substrates of the enzyme and subsequently administered a threshold hypotensive dose of the vasodilator. The SSAO substrates benzylamine, phenethylamine, and methylamine potentiate the hypotensive response to HYD. Methylamine, which was studied in greater detail because of its status as a possible endogenous SSAO substrate, does not influence the response to the reference vasodilator pinacidil; it does enhance HYD relaxation in aortic rings obtained from pretreated rats. Experiments designed to identify the product of SSAO activity responsible for potentiation by methylamine suggest involvement of hydrogen peroxide (H2O2), as evidenced by the findings that such potentiation is abolished by additional pretreatment with the H2O2-metabolizing enzyme catalase, and that the plasma concentration of H2O2 is increased by methylamine and decreased by HYD. These results are interpreted as a substantiation of the relation between the known SSAO inhibitory effect of HYD and its vasodilator activity. Pretreatment with the SSAO substrates would increase production of H2O2 in vascular smooth muscle and thus magnify the influence of this vasoconstrictor agent on vascular tone. In these conditions, the decrease in H2O2 production and hence in vascular tone caused by SSAO inhibition by HYD would also be magnified. It is speculated that inhibition of vascular SSAO could represent a novel mechanism of vasodilation.

  5. Effective plasma volume in cirrhosis with ascites. Evidence that a decreased value does not account for renal sodium retention, a spontaneous reduction in glomerular filtration rate (GFR), and a fall in GFR during drug-induced diuresis

    PubMed Central

    Lieberman, Fred L.; Ito, Sosuke; Reynolds, Telfer B.

    1969-01-01

    A reduction in effective (nonportal) plasma volume is considered the basis for renal sodium retention, a spontaneous reduction in glomerular filtration rate (GFR), and a fall in GFR occurring during drug-induced diuresis in patients with cirrhosis and ascites. In the present study the concept of a reduced effective plasma volume in cirrhosis is challenged by two lines of evidence, even though effective plasma volume itself could not be measured. (a) Total plasma volume failed to rise in 10 patients with the spontaneous loss of ascites, the appearance of sodium in the urine, and a rise in GFR. Portal pressure remained constant in these patients as ascites left, suggesting that effective plasma volume had not increased while portal plasma volume decreased. (b) Reduction of GFR could not be prevented in five patients with cirrhosis and ascites while total plasma volume was prevented from falling with albumin infusions during drug-induced diuresis. Reduction of GFR during drug-induced diuresis in 15 patients with cirrhosis and ascites was completely reversed with saline infusion despite continued diuresis with the identical drugs, excluding drug nephrotoxicity as the cause for the reduced GFR. The ascites of cirrhosis might no longer be regarded as a cause of effective plasma volume contraction, stimulating renal sodium retention and a reduction in GFR. More likely, this form of ascites is a result of plasma volume expansion and sodium retention. The causes for renal sodium retention and a spontaneous reduction in GFR remain unknown. The cause for a fall in GFR during drug-induced diuresis also remains unknown, but effective plasma volume contraction and drug nephrotoxicity seem excluded. Images PMID:5771197

  6. Low pre-operative heart rate variability and complexity are associated with hypotension after anesthesia induction in major abdominal surgery.

    PubMed

    Padley, James R; Ben-Menachem, Erez

    2017-03-14

    Significant hypotension after induction of general anesthesia is common and has the potential for serious complications. This study aimed to determine if pre-operative heart rate variability (HRV) was associated with post-induction hypotension in patients undergoing major abdominal surgery. Patients undergoing semi-elective major abdominal surgery were consecutively recruited during pre-admission clinic assessment. Exclusion criteria included cardiac conduction disease, arrhythmias or severe liver or renal disease. Ten minutes of electrocardiogram at 1024 Hz were recorded a median of 3 days pre-operatively. Pre-operative HRV parameters were compared in patients who experienced significant hypotension (fall in systolic and mean arterial pressure (MAP) >30% baseline and MAP ≤60 mmHg) versus those who remained haemodynamically stable after induction of general anesthesia with propofol and fentanyl. Patients who experienced hypotension after general anesthesia induction had significantly lower pre-operative HRV (SDNN 16 vs. 37 ms, p < 0.001), reduced spectral power (total power 262 vs. 1236 ms(2), p = 0.002) and reduced correlation dimension, a measure of signal complexity (0.11 vs. 2.13, p < 0.001). Hypotension occurred relatively frequently in our cohort and was associated with a higher ASA grade (36 vs. 6% ASA 3, p = 0.036), hence post-induction hypotension and lower HRV may be associated with severity of illness or poor physiological reserve. Pre-operative HRV was a useful screening tool in identifying patients undergoing major abdominal surgery who were at risk of haemodynamic instability after anesthesia induction.

  7. Interview with Professor Mark Wilcox.

    PubMed

    Wilcox, Mark

    2016-08-01

    Mark Wilcox speaks to Georgia Patey, Commissioning Editor: Professor Mark Wilcox is a Consultant Microbiologist and Head of Microbiology at the Leeds Teaching Hospitals (Leeds, UK), the Professor of Medical Microbiology at the University of Leeds (Leeds, UK), and is the Lead on Clostridium difficile and the Head of the UK C. difficile Reference Laboratory for Public Health England (PHE). He was the Director of Infection Prevention (4 years), Infection Control Doctor (8 years) and Clinical Director of Pathology (6 years) at the Leeds Teaching Hospitals. He is Chair of PHE's Rapid Review Panel (reviews utility of infection prevention and control products for National Health Service), Deputy Chair of the UK Department of Health's Antimicrobial Resistance and Healthcare Associated Infection Committee and a member of PHE's HCAI/AR Programme Board. He is a member of UK/European/US working groups on C. difficile infection. He has provided clinical advice as part of the FDA/EMA submissions for the approval of multiple novel antimicrobial agents. He heads a healthcare-associated infection research team at University of Leeds, comprising approximately 30 doctors, scientists and nurses; projects include multiple aspects of C. difficile infection, diagnostics, antimicrobial resistance and the clinical development of new antimicrobial agents. He has authored more than 400 publications, and is the coeditor of Antimicrobial Chemotherapy (5th/6th/7th Editions, 15 December 2007).

  8. Renal angiotensin II type-2 receptors are upregulated and mediate the candesartan-induced natriuresis/diuresis in obese Zucker rats.

    PubMed

    Hakam, Amer C; Hussain, Tahir

    2005-02-01

    Recently, there has been a growing interest in studying the role of angiotensin II type-2 (AT(2)) receptor in renal/cardiovascular function in pathological conditions. The present study was designed to determine the functional role of the AT(2) receptors on natriuresis/diuresis and compare the level of the tubular AT(2) receptor expression in obese and lean Zucker rats (12 weeks old). Under anesthesia, candesartan (angiotensin II type 1 [AT(1)]-specific antagonist; 100 microg/kg bolus) produced natriuresis/diuresis to a greater degree in obese than in lean rats. The specific AT(2) antagonist PD123319 (50 microg/kg per minute) after candesartan administration abolished the natriuretic/diuretic effects of candesartan in obese rats but not in lean rats. Infusion of AT(2) receptor agonist, CGP-42112A (1 microg/kg per minute), produced greater increase in sodium and urine excretion over basal in obese than in lean rats. The presence of the AT(2) receptor expression in the brush-border and basolateral membranes was confirmed by Western blotting using specific antibody and antigen-blocking peptide. Densitometric analysis of the bands revealed approximately 1.5- to 2.0-fold increase in the AT(2) receptor proteins in both membranes of obese compared with lean rats. Our results suggest upregulation of the AT(2) receptors, which play a role in mediating the natriuretic/diuretic effects of AT(1) receptor blockers in obese Zucker rats. We speculate that AT(2) receptors, by promoting sodium excretion, may protect obese Zucker rats against blood pressure increase associated with sodium and water retention.

  9. Urea and NaCl regulate UT-A1 urea transporter in opposing directions via TonEBP pathway during osmotic diuresis.

    PubMed

    Kim, Yu-Mi; Kim, Wan-Young; Lee, Hyun-Wook; Kim, Jin; Kwon, H Moo; Klein, Janet D; Sands, Jeff M; Kim, Dongun

    2009-01-01

    In our previous studies of varying osmotic diuresis, UT-A1 urea transporter increased when urine and inner medullary (IM) interstitial urea concentration decreased. The purposes of this study were to examine 1) whether IM interstitial tonicity changes with different urine urea concentrations during osmotic dieresis and 2) whether the same result occurs even if the total urinary solute is decreased. Rats were fed a 4% high-salt diet (HSD) or a 5% high-urea diet (HUD) for 2 wk and compared with the control rats fed a regular diet containing 1% NaCl. The urine urea concentration decreased in HSD but increased in HUD. In the IM, UT-A1 and UT-A3 urea transporters, CLC-K1 chloride channel, and tonicity-enhanced binding protein (TonEBP) transcription factor were all increased in HSD and decreased in HUD. Next, rats were fed an 8% low-protein diet (LPD) or a 0.4% low-salt diet (LSD) to decrease the total urinary solute. Urine urea concentration significantly decreased in LPD but significantly increased in LSD. Rats fed the LPD had increased UT-A1 and UT-A3 in the IM base but decreased in the IM tip, resulting in impaired urine concentrating ability. The LSD rats had decreased UT-A1 and UT-A3 in both portions of the IM. CLC-K1 and TonEBP were unchanged by LPD or LSD. We conclude that changes in CLC-K1, UT-A1, UT-A3, and TonEBP play important roles in the renal response to osmotic diuresis in an attempt to minimize changes in plasma osmolality and maintain water homeostasis.

  10. Role in diuresis of a calcitonin receptor (GPRCAL1) expressed in a distal-proximal gradient in renal organs of the mosquito Aedes aegypti (L.).

    PubMed

    Kwon, Hyeogsun; Lu, Hsiao-Ling; Longnecker, Michael T; Pietrantonio, Patricia V

    2012-01-01

    Evolution of anthropophilic hematophagy in insects resulted in the coordination of various physiological processes for survival. In female mosquitoes, a large blood meal provides proteins for egg production and as a trade-off, rapid elimination of the excess water and solutes (Na(+), Cl(-)) is critical for maintaining homeostasis and removing excess weight to resume flight and avoid predation. This post-prandial excretion is achieved by the concerted action of multiple hormones. Diuresis and natriuresis elicited by the calcitonin-like diuretic hormone 31 (DH(31)) are believed to be mediated by a yet uncharacterized calcitonin receptor (GPRCAL) in the mosquito Malpighian tubules (MTs), the renal organs. To contribute knowledge on endocrinology of mosquito diuresis we cloned GPRCAL1 from MT cDNA. This receptor is the ortholog of the DH(31) receptor from Drosophila melanogaster that is expressed in principal cells of the fruit fly MT. Immunofluorescence similarly showed AaegGPRCAL1 is present in MT principal cells in A. aegypti, however, exhibiting an overall gradient-like pattern along the tubule novel for a GPCR in insects. Variegated, cell-specific receptor expression revealed a subpopulation of otherwise phenotypically similar principal cells. To investigate the receptor contribution to fluid elimination, RNAi was followed by urine measurement assays. In vitro, MTs from females that underwent AaegGPRcal1 knock-down exhibited up to 57% decrease in the rate of fluid secretion in response to DH(31). Live females treated with AaegGPRcal1 dsRNA exhibited 30% reduction in fluid excreted after a blood meal. The RNAi-induced phenotype demonstrates the critical contribution of this single secretin-like family B GPCR to fluid excretion in invertebrates and highlights its relevance for the blood feeding adaptation. Our results with the mosquito AaegGPRCAL1 imply that the regulatory function of calcitonin-like receptors for ion and fluid transport in renal organs arose early

  11. Hypotensive effects of hemopressin and bradykinin in rabbits, rats and mice. A comparative study.

    PubMed

    Blais, Paul-André; Côté, Jérôme; Morin, Josée; Larouche, Annie; Gendron, Gabrielle; Fortier, Audrey; Regoli, Domenico; Neugebauer, Witold; Gobeil, Fernand

    2005-08-01

    Hemopressin is a novel vasoactive nonapeptide derived from hemoglobin's alpha-chain as recently reported by Rioli et al. [Rioli V, Gozzo FC, Heimann AS, Linardi A, Krieger JE, Shida CS, et al. Novel natural peptide substrates for endopeptidase 24.15, neurolysin, and angiotensin-converting enzyme. J Biol Chem 2003;278(10):8547-55]. In anesthetized male Wistar rats, this peptide exhibited hypotensive actions similar to those of bradykinin (BK) when administered intravenously (i.v.), and was found to be metabolized both in vitro and in vivo by several peptidases, including the angiotensin-converting enzyme (ACE). In this study, these findings were expanded upon by examining: (i) the degradation kinetics following incubation with ACE purified from rabbit lung and (ii) the blood pressure lowering effects of HP and BK injected i.v. or intra-arterially (i.a.) in male rabbits, rats, and mice. Our findings demonstrate that, in vitro, HP and BK are both degraded by ACE, but at different velocity rates. Furthermore, both HP and BK induced transient hypotension in all animals tested, although the responses to HP relative to the administration sites were significantly lower (by 10-100-fold) on an equimolar basis compared to those of BK. In rabbits, the decrease of blood pressure induced by HP (10-100 nmol/kg) did not differ whether it was administered i.v. or i.a., suggesting an absence of pulmonary/cardiac inactivation in contrast to BK (0.1-1 nmol/kg). The in vivo effect of HP was significantly potentiated in rabbits immunostimulated with bacterial lipopolysaccharide (LPS), but was unaffected by both the B2 receptor antagonist HOE 140 (0.1 micromol/kg) and captopril (100 microg/kg), contrary to BK. Therefore, HP acts as a weak hypotensive mediator, which does not activate kinin B2 receptors, but uses a functional site and/or signaling paths appearing to be up-regulated by LPS.

  12. Isometric handgrip does not elicit cardiovascular overload or post-exercise hypotension in hypertensive older women

    PubMed Central

    Olher, Rafael dos Reis Vieira; Bocalini, Danilo Sales; Bacurau, Reury Frank; Rodriguez, Daniel; Figueira, Aylton; Pontes, Francisco Luciano; Navarro, Francisco; Simões, Herbert Gustavo; Araujo, Ronaldo Carvalho; Moraes, Milton Rocha

    2013-01-01

    Background Arterial hypertension is a serious health problem affecting mainly the elderly population. Recent studies have considered both aerobic and resistance exercises as a non-pharmacological aid for arterial hypertension treatment. However, the cardiovascular responses of the elderly to isometric resistance exercise (eg, isometric handgrip [IHG]) have not yet been documented. Objective The purpose of this study was to investigate cardiovascular responses to different intensities of isometric exercise, as well as the occurrence of post-isometric exercise hypotension in hypertensive elderly people under antihypertensive medication treatment. Patients and methods Twelve women volunteered to participate in the study after a maximal voluntary contraction test (MVC) and standardization of the intervention workload consisting of two sessions of IHG exercise performed in four sets of five contractions of a 10-second duration. Sessions were performed both at 30% of the MVC and 50% of the MVC, using a unilateral IHG protocol. Both intensities were compared with a control session without exercise. Systolic blood pressure (SBP) and diastolic blood pressure (DBP) at rest (R), during peak exercise (PE), and after 5, 10, 15, 30, 45, and 60 minutes of post-exercise recovery were evaluated. Results No significant changes were observed after isometric exercise corresponding to 30% MVC for either SBP (R: 121 ± 10; PE: 127 ± 14; 5 min: 125 ± 13; 10 min: 123 ± 12; 15 min: 122 ± 11; 30 min: 124 ± 11; 45 min: 124 ± 10; 60 min: 121 ± 10 mmHg) or DBP (R: 74 ± 9; PE: 76 ± 6; 5 min: 74 ± 5; 10 min: 72 ± 8; 15 min: 72 ± 5; 30 min: 72 ± 8; 45 min: 73 ± 6; 60 min: 75 ± 7 mmHg). Similarly, the 50% MVC did not promote post-isometric exercise hypotension for either SBP (R: 120 ± 7; PE: 125 ± 11; 5 min: 120 ± 9; 10 min: 122 ± 9; 15 min: 121 ± 11; 30 min: 121 ± 9; 45 min: 121 ± 9; 60 min: 120 ± 7 mmHg) or DBP (R: 72 ± 8; PE: 78 ± 7; 5 min: 72 ± 7; 10 min: 72 ± 8; 15

  13. Methods to Mark Termites with Protein for Mark-Release-Recapture and Mark-Capture Type Studies.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Studies were conducted to investigate the feasibility of marking the southwestern desert subterranean termite, Heterotermes aureus (Snyder), with rabbit immunoglobulin G (IgG) protein for mark-release-recapture (MRR) and mark-capture type studies. Qualitative laboratory studies were conducted to de...

  14. The research of laser marking control technology

    NASA Astrophysics Data System (ADS)

    Zhang, Qiue; Zhang, Rong

    2009-08-01

    In the area of Laser marking, the general control method is insert control card to computer's mother board, it can not support hot swap, it is difficult to assemble or it. Moreover, the one marking system must to equip one computer. In the system marking, the computer can not to do the other things except to transmit marking digital information. Otherwise it can affect marking precision. Based on traditional control methods existed some problems, introduced marking graphic editing and digital processing by the computer finish, high-speed digital signal processor (DSP) control marking the whole process. The laser marking controller is mainly contain DSP2812, digital memorizer, DAC (digital analog converting) transform unit circuit, USB interface control circuit, man-machine interface circuit, and other logic control circuit. Download the marking information which is processed by computer to U disk, DSP read the information by USB interface on time, then processing it, adopt the DSP inter timer control the marking time sequence, output the scanner control signal by D/A parts. Apply the technology can realize marking offline, thereby reduce the product cost, increase the product efficiency. The system have good effect in actual unit markings, the marking speed is more quickly than PCI control card to 20 percent. It has application value in practicality.

  15. Hypotension based on office and ambulatory monitoring blood pressure. Prevalence and clinical profile among a cohort of 70,997 treated hypertensives.

    PubMed

    Divisón-Garrote, Juan A; Banegas, José R; De la Cruz, Juan J; Escobar-Cervantes, Carlos; De la Sierra, Alejandro; Gorostidi, Manuel; Vinyoles, Ernest; Abellán-Aleman, José; Segura, Julián; Ruilope, Luis M

    2016-09-01

    We aimed to determine the prevalence of hypotension and factors associated with the presence of this condition in treated hypertensive patients undergoing ambulatory blood pressure monitoring (ABPM). Data were taken from the Spanish ABPM Registry. Office blood pressure (BP) and ABPM were determined using validated devices under standardized conditions. Based on previous studies, hypotension was defined as office systolic/diastolic BP <110 and/or 70 mm Hg, daytime ABPM <105 and/or 65 mm Hg, nighttime ABPM <90 and/or 50 mm Hg, and 24-hour ABPM <100 and/or 60 mm Hg. Multivariable logistic regression was performed to determine the variables associated with the presence of hypotension. A total of 70,997 hypertensive patients on treatment (mean age 61.8 years, 52.5% men) were included in the study. The prevalence of hypotension was 8.2% with office BP, 12.2% with daytime ABPM, 3.9% with nighttime ABPM, and 6.8% with 24-hour ABPM. Low diastolic BP values were responsible for the majority of cases of hypotension. Some 68% of the hypotension cases detected by daytime ABPM did not correspond to hypotension according to office BP. The variables independently and consistently associated with higher likelihood of office, daytime, and 24 hour-based hypotension were age, female gender, history of ischemic heart disease, and body mass index <30 kg/m(2) (P < .05). In conclusion, in this large cohort of patients in usual daily practice, one in eight treated hypertensive patients are at risk of hypotension according to daytime BP. Two-thirds of them are not adequately identified with office BP. ABPM could be especially helpful for identifying ambulatory hypotension, in particular in patients who are older, women, or with previous ischemic heart disease where antihypertensive treatment should be especially individualized and cautious.

  16. Permissive hypotension does not reduce regional organ perfusion compared to normotensive resuscitation: animal study with fluorescent microspheres

    PubMed Central

    2012-01-01

    Introduction The objective of this study was to investigate regional organ perfusion acutely following uncontrolled hemorrhage in an animal model that simulates a penetrating vascular injury and accounts for prehospital times in urban trauma. We set forth to determine if hypotensive resuscitation (permissive hypotension) would result in equivalent organ perfusion compared to normotensive resuscitation. Methods Twenty four (n=24) male rats randomized to 4 groups: Sham, No Fluid (NF), Permissive Hypotension (PH) (60% of baseline mean arterial pressure - MAP), Normotensive Resuscitation (NBP). Uncontrolled hemorrhage caused by a standardised injury to the abdominal aorta; MAP was monitored continuously and lactated Ringer’s was infused. Fluorimeter readings of regional blood flow of the brain, heart, lung, kidney, liver, and bowel were obtained at baseline and 85 minutes after hemorrhage, as well as, cardiac output, lactic acid, and laboratory tests; intra-abdominal blood loss was assessed. Analysis of variance was used for comparison. Results Intra-abdominal blood loss was higher in NBP group, as well as, lower hematocrit and hemoglobin levels. No statistical differences in perfusion of any organ between PH and NBP groups. No statistical difference in cardiac output between PH and NBP groups, as well as, in lactic acid levels between PH and NBP. NF group had significantly higher lactic acidosis and had significantly lower organ perfusion. Conclusions Hypotensive resuscitation causes less intra-abdominal bleeding than normotensive resuscitation and concurrently maintains equivalent organ perfusion. No fluid resuscitation reduces intra-abdominal bleeding but also significantly reduces organ perfusion. PMID:23531188

  17. The Impact of Hypotensive Epidural Anesthesia on Distal and Proximal Tissue Perfusion in Patients Undergoing Total Hip Arthroplasty.

    PubMed

    Danninger, Thomas; Stundner, Ottokar; Ma, Yan; Bae, James J; Memtsoudis, Stavros G

    2013-11-29

    Little data exists to detail the effect of hypotensive epidural anesthesia on differential tissue oxygenation changes above and below the level of neuraxial blockade. This study was designed to investigate tissue oxygenation in a clinical setting, using non-invasive near-infrared spectroscopy.

  18. Carotid-cardiac baroreflex: Relation with orthostatic hypotension following simulated microgravity and implications for development of countermeasures

    NASA Technical Reports Server (NTRS)

    Convertino, Victor A.

    1991-01-01

    In a series of studies, we have examined the effects of exposure to simulated microgravity, varying states of vascular volume, and acute exercise on the function of the carotid-cardiac baroreflex in man. In the first study, exposure to simulated microgravity (6 degree headdown bedrest) reduced the sensitivity and buffer capacity of the vagal baroreceptor-cardiac reflex mechanisms and this impaired baroreflex function was associated with orthostatic hypotension. Since the reduction in plasma volume during BR was not correlated with impaired baroreflex function, a second study was conducted which demonstrated that the carotid-cardiac baroreflex response was not affected by either acute hypovolemia or hypervolemia. These results suggest that acute fluid replacement prior to reentry may not reverse impaired baroreflex function associated with postflight hypotension. In a third study, we demonstrated that one bout of maximal exercise increased baroreflex sensitivity and buffer capacity through 24 h post-exercise. These baroreflex changes were opposite to those observed following BR. Taken together, these data suggest that the contributions of reduced blood volume and impaired carotid-cardiac baroreflex function to orthostatic hypotension following exposure to microgravity are probably separate and additive; maximal exercise in addition to fluid replacement may provide an acute effective countermeasure against postflight hypotension.

  19. Carotid-cardiac baroreflex: Relation with orthostatic hypotension following simulated microgravity and implications for development of countermeasures

    NASA Astrophysics Data System (ADS)

    Convertino, Victor A.

    In a series of studies, we have examined the effects of exposure to simulated microgravity, varying states of vascular volume, and acute exercise on the function of the carotid-cardiac baroreflex in man. In the first study, exposure to simulated microgravity (6° headdown bedrest) reduced the sensitivity and buffer capacity of the vagal baroreceptor-cardiac reflex mechanisms and this impaired baroreflex function was associated with orthostatic hypotension. Since the reduction in plasma volume during BR was not correlated with impaired baroreflex function, a second study was conducted which demonstrated that the carotid-cardiac baroreflex response was not affected by either acute hypovolemia or hypervolemia. These results suggest that acute fluid replacement prior to reentry may not reverse impaired baroreflex function associated with postflight hypotension. In a third study, we demonstrated that one bout of maximal exercise increased baroreflex sensitivity and buffer capacity through 24 h post-exercise. These baroreflex changes were opposite to those observed following BR. Taken together, these data suggest that the contributions of reduced blood volume and impaired carotid-cardiac baroreflex function to orthostatic hypotension following exposure to microgravity are probably separate and additive; maximal exercise in addition to fluid replacement may provide an acute effective countermeasure against postflight hypotension.

  20. The incidence and risk factors for hypotension during emergent decompressive craniotomy in children with traumatic brain injury.

    PubMed

    Miller, Patrick; Mack, Christopher D; Sammer, Marla; Rozet, Irene; Lee, Lorri A; Muangman, Saipin; Wang, Marjorie; Hollingworth, Will; Lam, Arthur M; Vavilala, Monica S

    2006-10-01

    We conducted a retrospective cohort study in children <13 yr with traumatic brain injury (TBI) at a Level 1 pediatric trauma center to describe risk factors for intraoperative hypotension (IH) during emergent decompressive craniotomy. Between 1994 and 2004, 108 children underwent emergent decompressive craniotomy for TBI. Overall, 56 (52%) patients had IH. Independent risk factors for IH were each 10 mL estimated blood loss/kg (ARR 1.15 95% CI 1.08-1.22), each mm of computed tomography (CT) midline shift (ARR 1.04 95%CI 1.01-1.07), each 10 mL of CT lesion volume (ARR 1.03 95%CI 1.01-1.05), and emergency department (ED) hypotension (5/5 patients with ED hypotension had IH). CT midline shift > or =4 mm predicted IH (ARR 1.67 95% CI 1.06-2.63), independent of blood loss. IH occurred frequently during emergent decompressive craniotomy in children with TBI. ED hypotension, blood loss, CT lesion volume, and CT midline shift predicted IH. Anesthesiologists can expect children with preoperative CT midline shift > or =4 mm to have IH during this procedure.

  1. Enhancement of hydralazine hypotension by low doses of isoniazid. Possible role of semicarbazide-sensitive amine oxidase inhibition.

    PubMed

    Vidrio, H; Medina, M; Fernandez, G; Lorenzana-Jimenez, M; Campos, A E

    2000-10-01

    The influence of pretreatment with 1 through 300 mg/kg ip of isoniazid (ISO) on blood pressure and heart rate responses to 0.1 mg/kg iv of hydralazine (HYD) was assessed in rats anesthetized with chloralose--urethane. HYD hypotension was significantly enhanced by ISO at doses between 3 and 300 mg/kg ip. Heart rate was not influenced by HYD in control or pretreated animals. Depressor responses to 0.2 mg/kg iv of pinacidil (PIN) were also potentiated by ISO at 100 and 300, but not at 30 mg/kg. Similarly, ISO decreased cerebral gamma-aminobutyric acid (GABA) at the two highest doses; 30 mg/kg was without effect. Pretreatment of rats with ISO at 1 through 300 mg/kg failed to influence HYD-induced relaxation of aortic rings. These results were interpreted as indicating that potentiation of HYD hypotension by high doses of ISO is not specific for that vasodilator and is related to decreased cerebral GABA, as postulated previously. Lower doses could specifically potentiate the HYD-induced hypotensive effect by inhibition of semicarbazide-sensitive amine oxidase (SSAO), since both ISO and HYD are potent inhibitors of this enzyme. In support of this hypothesis, the SSAO inhibitors, benserazide (100 mg/kg ip) and mexiletine (50 mg/kg ip), were also found to enhance HYD hypotension.

  2. 30 CFR 7.29 - Approval marking.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... MINING PRODUCTS TESTING BY APPLICANT OR THIRD PARTY Brattice Cloth and Ventilation Tubing § 7.29 Approval marking. (a) Approved brattice cloth shall be legibly and permanently marked with the assigned...

  3. 30 CFR 7.29 - Approval marking.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... MINING PRODUCTS TESTING BY APPLICANT OR THIRD PARTY Brattice Cloth and Ventilation Tubing § 7.29 Approval marking. (a) Approved brattice cloth shall be legibly and permanently marked with the assigned...

  4. 30 CFR 7.29 - Approval marking.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... MINING PRODUCTS TESTING BY APPLICANT OR THIRD PARTY Brattice Cloth and Ventilation Tubing § 7.29 Approval marking. (a) Approved brattice cloth shall be legibly and permanently marked with the assigned...

  5. 30 CFR 7.29 - Approval marking.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... MINING PRODUCTS TESTING BY APPLICANT OR THIRD PARTY Brattice Cloth and Ventilation Tubing § 7.29 Approval marking. (a) Approved brattice cloth shall be legibly and permanently marked with the assigned...

  6. 30 CFR 7.29 - Approval marking.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... MINING PRODUCTS TESTING BY APPLICANT OR THIRD PARTY Brattice Cloth and Ventilation Tubing § 7.29 Approval marking. (a) Approved brattice cloth shall be legibly and permanently marked with the assigned...

  7. 46 CFR 160.016-4 - Marking.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Lamps, Safety, Flame, for Merchant Vessels § 160.016-4 Marking. (a) Flame safety lamps shall be permanently and legibly marked with the name and address of...

  8. 46 CFR 160.016-4 - Marking.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Lamps, Safety, Flame, for Merchant Vessels § 160.016-4 Marking. (a) Flame safety lamps shall be permanently and legibly marked with the name and address of...

  9. 46 CFR 160.016-4 - Marking.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Lamps, Safety, Flame, for Merchant Vessels § 160.016-4 Marking. (a) Flame safety lamps shall be permanently and legibly marked with the name and address of...

  10. 46 CFR 160.016-4 - Marking.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Lamps, Safety, Flame, for Merchant Vessels § 160.016-4 Marking. (a) Flame safety lamps shall be permanently and legibly marked with the name and address of...

  11. 46 CFR 160.016-4 - Marking.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Lamps, Safety, Flame, for Merchant Vessels § 160.016-4 Marking. (a) Flame safety lamps shall be permanently and legibly marked with the name and address of...

  12. 14 CFR 29.1555 - Control markings.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Operating Limitations and Information Markings and Placards § 29... fuel controls— (1) Each fuel tank selector valve control must be marked to indicate the...

  13. 14 CFR 29.1555 - Control markings.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Operating Limitations and Information Markings and Placards § 29... fuel controls— (1) Each fuel tank selector valve control must be marked to indicate the...

  14. 14 CFR 29.1555 - Control markings.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Operating Limitations and Information Markings and Placards § 29... fuel controls— (1) Each fuel tank selector valve control must be marked to indicate the...

  15. [Sensitization of bradycardia during final hypotension induced by serotonin in rats: effect of lidocaine].

    PubMed

    Valle, L B; Oliveira-Filho, R M; Armonia, P L; Nassif, M; Saraceni, G

    1975-10-01

    It was studied the sensibilizing effect of lidocaine (8.5 mg/kg, i.v.) on the ECG (heart rate, P-R interval, QRS complex and Q-T interval) of both intact and bilaterally vagotomised rats, in the nadir of the final hypotension determined by serotonine (60 mug/kg, i.v.). The results showed (1) a certain degree of selectivity of the vagi, and (2) the effects of serotonine either isolated or associated to lidocaine on P-R interval and heart rate were reinforced when intact animals were used. Although no significant alterations of Q-T were elicited by the drugs, lidocaine surprisingly enlarged the QRS complex in a more significant fashion for the intact than for the vagotomised animals.

  16. Hypotensive bradycardic events during shoulder arthroscopic surgery under interscalene brachial plexus blocks

    PubMed Central

    Song, Seok Young

    2012-01-01

    Sudden, profound hypotensive and bradycardic events (HBEs) have been reported in more than 20% of patients undergoing shoulder arthroscopy in the sitting position. Although HBEs may be associated with the adverse effects of interscalene brachial plexus block (ISBPB) in the sitting position, the underlying mechanisms responsible for HBEs during the course of shoulder surgery are not well understood. The basic mechanisms of HBEs may be associated with the underlying mechanisms responsible for vasovagal syncope, carotid sinus hypersensitivity or orthostatic syncope. In this review, we discussed the possible mechanisms of HBEs during shoulder arthroscopic surgery, in the sitting position, under ISBPB. In particular, we focused on the relationship between HBEs and various types of syncopal reactions, the relationship between HBEs and the Bezold-Jarisch reflex, and the new contributing factors for the occurrence of HBEs, such as stellate ganglion block or the intraoperative administration of intravenous fentanyl. PMID:22474545

  17. Dynamic left ventricular outflow tract obstruction: underestimated cause of hypotension and hemodynamic instability

    PubMed Central

    2014-01-01

    Left ventricular outflow tract obstruction, which is typically associated with hypertrophic cardiomyopathy, is the third most frequent cause of unexplained hypotension. This underestimated problem may temporarily accompany various diseases (it is found in even <1% of patients with no tangible cardiac disease) and clinical situations (hypovolemia, general anesthesia). It is currently assumed that left ventricular outflow tract obstruction is a dynamic phenomenon, the occurrence of which requires the coexistence of predisposing anatomic factors and a physiological condition that induces it. The diagnosis of left ventricular outflow tract obstruction should entail immediate implementation of the therapy to eliminate the factors that can potentially intensify the obstruction. Echocardiography is the basic modality in the diagnosis and treatment of left ventricular outflow tract obstruction. This paper presents four patients in whom the immediate implementation of bedside echocardiography enabled a rapid diagnosis of left ventricular outflow tract obstruction and implementation of proper treatment. PMID:26674265

  18. Hypotensive and toxicological study of citric acid and other constituents from Tagetes patula roots.

    PubMed

    Saleem, Rubeena; Ahmad, Mohammad; Naz, Aneela; Siddiqui, Humaira; Ahmad, Syed Iqbal; Faizi, Shaheen

    2004-10-01

    Study of the effects of the methanolic extract of Tagetes patula roots on blood pressure led to the isolation of well known citric (1) and malic acid (7) as hypotensive, and pyridine hydrochloride (4) as hypertensive constituents of the plant along with a new constituent, 2-hydroxy, 5-hydroxymethyl furan (9). Citric acid and malic acid caused 71% and 43% fall in Mean Arterial Blood Pressure (MABP) of rats at the doses of 15 mg/kg and 30 mg/kg respectively while pyridine hydrochloride produced 34% rise in the MABP of rats at the dose of 30 mg/kg. LD50 and LD100 of citric acid in mice have been determined as 545 mg/kg and 1000 mg/kg, respectively.

  19. Idiopathic orthostatic hypotension: Recent data (eleven cases) and review of the literature

    NASA Technical Reports Server (NTRS)

    Ninet, J.; Annat, G.; Boisson, D.; Holzhapfel, L.; Vincent, M.; Peyrin, L.; Michel, D.; Schott, B.; Devic, M.; Levrat, R.

    1981-01-01

    Eight cases of Shy-Drager syndrome and three of Bradbury-Eggleston idiopathic orthostatic hypotension were examined. In all cases, examination of circulatory reflexes showed major dysfunction of the sympathetic vasoconstrictor system. Anomalies in the vagal cardiomoderator system were less constant. Normal urinary elimination of catecholamines was recorded daily. Characteristically, no elevation of blood or urine norepinephrine levels were found in orthostatism. Insulin hypoglycemia normally raised urinary adrenalin elimination in three of ten patients. Plasma dopa-beta-hydroxylase activity was normal. Renin-angiotensin-aldosterone system showed variable activity at basal state but usually rose during orthostatism. On the average, very low homovanillic acid levels were found in cerebrospinal fluid before and after probenecid; hydroxyindolacetic acid was normal. Cerebral autoregulation had deteriorated in two of four cases. Physiopathologically the two clinical types are indistinguishable with or without central neurological signs.

  20. A de novo transcriptome of the Malpighian tubules in non-blood-fed and blood-fed Asian tiger mosquitoes Aedes albopictus: insights into diuresis, detoxification, and blood meal processing

    PubMed Central

    Esquivel, Carlos J.; Cassone, Bryan J.

    2016-01-01

    Background. In adult female mosquitoes, the renal (Malpighian) tubules play an important role in the post-prandial diuresis, which removes excess ions and water from the hemolymph of mosquitoes following a blood meal. After the post-prandial diuresis, the roles that Malpighian tubules play in the processing of blood meals are not well described. Methods. We used a combination of next-generation sequencing (paired-end RNA sequencing) and physiological/biochemical assays in adult female Asian tiger mosquitoes (Aedes albopictus) to generate molecular and functional insights into the Malpighian tubules and how they may contribute to blood meal processing (3–24 h after blood ingestion). Results/Discussion. Using RNA sequencing, we sequenced and assembled the first de novo transcriptome of Malpighian tubules from non-blood-fed (NBF) and blood-fed (BF) mosquitoes. We identified a total of 8,232 non-redundant transcripts. The Malpighian tubules of NBF mosquitoes were characterized by the expression of transcripts associated with active transepithelial fluid secretion/diuresis (e.g., ion transporters, water channels, V-type H+-ATPase subunits), xenobiotic detoxification (e.g., cytochrome P450 monoxygenases, glutathione S-transferases, ATP-binding cassette transporters), and purine metabolism (e.g., xanthine dehydrogenase). We also detected the expression of transcripts encoding sodium calcium exchangers, G protein coupled-receptors, and septate junctional proteins not previously described in mosquito Malpighian tubules. Within 24 h after a blood meal, transcripts associated with active transepithelial fluid secretion/diuresis exhibited a general downregulation, whereas those associated with xenobiotic detoxification and purine catabolism exhibited a general upregulation, suggesting a reinvestment of the Malpighian tubules’ molecular resources from diuresis to detoxification. Physiological and biochemical assays were conducted in mosquitoes and isolated Malpighian

  1. A de novo transcriptome of the Malpighian tubules in non-blood-fed and blood-fed Asian tiger mosquitoes Aedes albopictus: insights into diuresis, detoxification, and blood meal processing.

    PubMed

    Esquivel, Carlos J; Cassone, Bryan J; Piermarini, Peter M

    2016-01-01

    Background. In adult female mosquitoes, the renal (Malpighian) tubules play an important role in the post-prandial diuresis, which removes excess ions and water from the hemolymph of mosquitoes following a blood meal. After the post-prandial diuresis, the roles that Malpighian tubules play in the processing of blood meals are not well described. Methods. We used a combination of next-generation sequencing (paired-end RNA sequencing) and physiological/biochemical assays in adult female Asian tiger mosquitoes (Aedes albopictus) to generate molecular and functional insights into the Malpighian tubules and how they may contribute to blood meal processing (3-24 h after blood ingestion). Results/Discussion. Using RNA sequencing, we sequenced and assembled the first de novo transcriptome of Malpighian tubules from non-blood-fed (NBF) and blood-fed (BF) mosquitoes. We identified a total of 8,232 non-redundant transcripts. The Malpighian tubules of NBF mosquitoes were characterized by the expression of transcripts associated with active transepithelial fluid secretion/diuresis (e.g., ion transporters, water channels, V-type H(+)-ATPase subunits), xenobiotic detoxification (e.g., cytochrome P450 monoxygenases, glutathione S-transferases, ATP-binding cassette transporters), and purine metabolism (e.g., xanthine dehydrogenase). We also detected the expression of transcripts encoding sodium calcium exchangers, G protein coupled-receptors, and septate junctional proteins not previously described in mosquito Malpighian tubules. Within 24 h after a blood meal, transcripts associated with active transepithelial fluid secretion/diuresis exhibited a general downregulation, whereas those associated with xenobiotic detoxification and purine catabolism exhibited a general upregulation, suggesting a reinvestment of the Malpighian tubules' molecular resources from diuresis to detoxification. Physiological and biochemical assays were conducted in mosquitoes and isolated Malpighian tubules

  2. Evaluation of sodium nitroprusside for controlled hypotension in children during surgery

    PubMed Central

    Drover, David R.; Hammer, Gregory B.; Barrett, Jeffrey S.; Cohane, Carol A.; Reece, Tammy; Zajicek, Anne; Schulman, Scott R.

    2015-01-01

    Purpose: (1) To define the onset and offset of the blood-pressure-lowering effects of sodium nitroprusside (SNP) for use in developing instructions for dose titration in children undergoing a surgical or medical procedure, and (2) to assess the safety of SNP administration in pediatric patients requiring controlled reduction of blood pressure. Methods: We conducted a randomized, double-blind, parallel-group, dose-ranging, effect-controlled, multicenter study of intravenous (IV) infusions of SNP in pediatric patients <17 years, who required controlled hypotension for at least 2 h while undergoing a surgical or medical procedure. A blinded SNP dose of 0.3, 1, 2, or 3 μg/kg/min was infused for 30 min, followed by open-label administration for at least 90 min. Both infusions were titrated to effect. Results: The final intent-to-treat group comprised 203 patients. Significant reductions in mean arterial pressure (MAP) from baseline were observed for all four doses at 20 and 25 min after the start of infusion (p ≤ 0.009 and p ≤ 0.010 for each time, respectively). Overall, 98.5% of the patients achieved the target MAP; 72.9% first achieved the target MAP during the blinded infusion. The mean infusion rate at target MAP was 1.07 μg/kg/min. Conclusion: We determined that 0.3 μg/kg/m is a reasonable starting dose for SNP in pediatric patients requiring controlled hypotension. The infusion rate can then be increased to achieve the desired reduction in blood pressure. On the basis of our results, we found an average infusion rate of 1 μg/kg/min might be appropriate. Of note, no cyanide toxicity was reported, and no measureable cyanide levels were detected in any blood samples obtained during the study. http://clinicaltrials.gov/show/NCT00135668. PMID:26217225

  3. VEGF improves myocardial blood flow but produces EDRF-mediated hypotension in porcine hearts.

    PubMed

    Hariawala, M D; Horowitz, J R; Esakof, D; Sheriff, D D; Walter, D H; Keyt, B; Isner, J M; Symes, J F

    1996-06-01

    Several recent studies have demonstrated the potential for improving myocardial perfusion by the continuous administration of angiogenic growth factors. Studies in our laboratory have shown that a single intraarterial or intravenous bolus of the endothelial cell specific mitogen vascular endothelial growth factor (VEGF) can significantly improve perfusion in a rabbit ischemic limb model. To test the efficacy of this therapeutic approach in chronic myocardial ischemia, 18 Yorkshire pigs underwent a left thoracotomy followed by placement of an ameroid constrictor around the proximal circumflex coronary artery. Gradual occlusion of the artery (26 +/- 4 days) was accompanied by identifiable hypokinesis of the posterolateral wall of the left ventricle (2D echo). Thirty days postoperatively, rhVEGF(165) (2 mg; n = 8) or saline (n = 10) was administered directly into the left coronary ostium. Postadenosine myocardial perfusion studies using colored microspheres 30 days later demonstrated superior blood flow in the ischemic zone of the VEGF-treated hearts (ischemic/normal ratio 1.09 vs 0.97, P < 0.05) compared with those receiving saline injection. Four of eight VEGF-treated animals succumbed, however, to severe hypotension following VEGF administration. Therefore 500 micrograms of VEGF were administered intracoronary to five normal pigs. A significant drop in mean arterial pressure (-44.4 +/- 3.2%, P < 0.05 vs baseline) and peripheral resistance (-13.2 +/- 4.5%, P < 0.05 vs baseline) was accompanied by increased heart rate. IV administration of N(omega)-nitro-L-arginine (L-NNA), an EDRF inhibitor, restored blood pressure to baseline. We conclude that a single intracoronary bolus of VEGF is capable of significantly augmenting flow to collateral-dependent ischemic myocardium. The associated hypotension appears to be EDRF-mediated. Further studies are needed to define the best dose and route of administration of VEGF for the treatment of coronary insufficiency.

  4. A diminished aortic-cardiac reflex during hypotension in aerobically fit young men

    NASA Technical Reports Server (NTRS)

    Shi, X.; Crandall, C. G.; Potts, J. T.; Williamson, J. W.; Foresman, B. H.; Raven, P. B.

    1993-01-01

    We compared the aortic-cardiac baroreflex sensitivity in eight average fit (AF: VO2max = 44.7 +/- 1.3 ml.kg-1 x min-1) and seven high fit (HF: VO2max = 64.1 +/- 1.7 ml.min-1 x kg-1) healthy young men during hypotension elicited by steady state sodium nitroprusside (SN) infusion. During SN mean arterial pressure (MAP) was similarly decreased in AF (-12.6 +/- 1.0 mm Hg) and HF (-12.1 +/- 1.1 mm Hg). However, the increases in heart rate (HR) were less (P < 0.023) in HF (15 +/- 3 bpm) than AF (25 +/- 1 bpm). When sustained neck suction (NS, -22 +/- 1 torr in AF and -20 +/- 1 torr in HF, P > 0.05) was applied to counteract the decreased carotid sinus transmural pressure during SN, thereby isolating the aortic baroreceptors, the increased HR remained less (P < 0.021) in HF (8 +/- 2 bpm) than AF (16 +/- 2 bpm). During both SN infusion and SN+NS, the calculated gains (i.e., delta HR/delta MAP) were significantly greater in AF (2.1 +/- 0.3 and 1.3 +/- 0.2 bpm.mm Hg-1) than HF (1.2 +/- 0.2 and 0.6 +/- 0.2 bpm.mm Hg-1). However, the estimated carotid-cardiac baroreflex sensitivity (i.e., the gain difference between the stage SN and SN + NS) was not different between AF (0.7 +/- 0.2 bpm.mm Hg-1) and HF (0.6 +/- 0.1 bpm.mm Hg-1). These data indicated that the aortic-cardiac baroreflex sensitivity during hypotension was significantly diminished with endurance exercise training.

  5. Ocular hypotensive efficacy and safety of a combined formulation of betaxolol and pilocarpine.

    PubMed Central

    Robin, A L

    1996-01-01

    PURPOSE: To evaluate the ocular hypotensive efficacy and safety of a fixed combination of betaxolol (0.25%) and pilocarpine (1.75%). METHODS: Three multicenter, double-masked, parallel trials were completed in patients with primary open-angle glaucoma or ocular hypertension of 3 months' treatment duration. Studies 1 and 2 were three-arm comparisons of betaxolol, pilocarpine, and a fixed combination, each used 3 times daily. Study 3 was a two-arm study of the fixed combination with and without a surfactant, used twice daily. In all studies, there was a 1-month runin period with betaxolol 0.25% suspension given twice daily. There were 182 patients in Study 1, 186 patients in Study 2, and 166 patients in Study 3. RESULTS: In all 3 studies, approximately 10% to 15% of patients treated with pilocarpine or the combination therapy were terminated from further participation because of typical pilocarpine side effects (eg, blurred vision, headache). In studies 1 and 2, there was a mean reduction in intraocular pressure from a betaxolol baseline of approximately 3 to 4 mmHg. Patients continuing on betaxolol alone or randomly assigned to pilocarpine alone experienced a mean reduction of 1 to 2 mm Hg. Overall, the combination was approximately 2 mmHg more effective than either betaxolol or pilocarpine alone. In Study 3, the two betaxolol combinations had equivalent efficacy. CONCLUSION: In patients requiring more than one ocular hypotensive agent, the combination of betaxolol and pilocarpine in a single formulation appears to be an effective and relatively safe agent. The use of this combination agent promises the potential for enhanced patient convenience. PMID:8981691

  6. Midodrine as a Countermeasure to Orthostatic Hypotension Immediately After Space Shuttle Landing

    NASA Technical Reports Server (NTRS)

    Platts, Steven H.; Stenger, Michael B.; Ribeiro, L. Christine; Lee, Stuart M. C.

    2010-01-01

    Midodrine prevents post-space flight orthostatic intolerance when testing is conducted in a controlled laboratory setting within 2-4 hours after Space Shuttle landing. It is unknown if midodrine is as effective during re-entry and immediately following landing. METHODS: Cardiovascular responses to 10 minutes of 80 head-up tilt in five male astronauts were compared before and immediately after Space Shuttle missions. Preflight tests were conducted in the Johnson Space Center Cardiovascular Laboratory without midodrine. Post-flight testing was performed in the Crew Transport Vehicle on the Space Shuttle runway within 60 minutes of landing; midodrine was self-administered before re-entry. Survival analysis was performed (Gehan-Breslow test) to compare presyncope rates pre- to post-flight. Cardiovascular responses (last minute standing minus supine) to tilt before and after space flight were compared using paired t-tests. RESULTS: Midodrine did not prevent post-flight orthostatic hypotension in two of the five astronauts, but the rate of presyncope across the group did not increase (p=0.17) from pre- to post-flight. Also, although the change in heart rate from supine to the last minute of standing was not affected by space flight, systolic blood pressure decreased more (p=0.05) and diastolic blood pressure tended to decrease (p=0.08) after space flight. CONCLUSIONS: Accurate interpretation of the current results requires that similar data be collected in control subjects (without midodrine) on the CTV. However, drug interaction concerns with commonly used anti-emetics and potentiation of prolonged QTc intervals observed in long duration astronauts make the routine use of midodrine for immediate post-flight orthostatic hypotension unlikely. 2

  7. Mark III results from SPEAR

    SciTech Connect

    Toki, W.

    1983-11-01

    First results from the MARK III detector at SPEAR are presented based on 2.7 million J/psi decays. The eta/sub c/ is observed in three modes, J/psi ..-->.. ..gamma..eta/sub c/, (eta/sub c/ ..-->.. rho anti rho, eta..pi../sup +/..pi../sup -/, and phi phi). Using the phi phi mode, the eta/sub c/ spin-parity is determined to be 0/sup -/. The known radiative J/psi decays J/psi ..-->.. ..gamma..f(f ..-->.. ..pi../sup +/..pi../sup -/), ..gamma..eta'(eta' ..-->.. ..gamma..rho/sup 0/, eta..pi../sup +/..pi../sup -/), ..gamma..f'(f' ..-->.. kappa/sup +/kappa/sup -/), ..gamma..theta(theta ..-->.. kappa anti kappa), and ..gamma..iota(iota ..-->.. ..pi..kappa anti kappa) are observed and their branching ratios found to be in agreement with previous measurements. In the J/psi ..-->.. ..gamma..kappa/sup +/kappa/sup -/ mode a new state is observed at 2.22 GeV and in the J/psi ..-->.. ..gamma gamma..rho/sup 0/ and ..gamma..eta..pi../sup +/..pi../sup -/ modes evidence for new structures near 1.4 GeV is presented. 29 references.

  8. Degradation Modeling of Polyurea Pavement Markings

    DTIC Science & Technology

    2011-03-01

    DEGRADATION MODELING OF POLYUREA PAVEMENT MARKINGS THESIS Jonathan D. Needham, Captain, USAF AFIT/GEM/ENV/11-M05 DEPARTMENT OF THE...DEGRADATION MODELING OF POLYUREA PAVEMENT MARKINGS THESIS Presented to the Faculty Department of Engineering Management Graduates School of...DEGRADATION MODELING OF POLYUREA PAVEMENT MARKINGS Jonathan D. Needham, BS Captain, USAF Approved

  9. 49 CFR 221.14 - Marking devices.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ..., DEPARTMENT OF TRANSPORTATION REAR END MARKING DEVICE-PASSENGER, COMMUTER AND FREIGHT TRAINS Marking Devices § 221.14 Marking devices. (a) As prescribed in § 221.13, passenger, commuter and freight trains shall be... and commuter trains in compliance with paragraph (a) of this section shall be lighted under...

  10. 49 CFR 221.14 - Marking devices.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ..., DEPARTMENT OF TRANSPORTATION REAR END MARKING DEVICE-PASSENGER, COMMUTER AND FREIGHT TRAINS Marking Devices § 221.14 Marking devices. (a) As prescribed in § 221.13, passenger, commuter and freight trains shall be... and commuter trains in compliance with paragraph (a) of this section shall be lighted under...

  11. 49 CFR 221.14 - Marking devices.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ..., DEPARTMENT OF TRANSPORTATION REAR END MARKING DEVICE-PASSENGER, COMMUTER AND FREIGHT TRAINS Marking Devices § 221.14 Marking devices. (a) As prescribed in § 221.13, passenger, commuter and freight trains shall be... and commuter trains in compliance with paragraph (a) of this section shall be lighted under...

  12. 49 CFR 221.14 - Marking devices.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ..., DEPARTMENT OF TRANSPORTATION REAR END MARKING DEVICE-PASSENGER, COMMUTER AND FREIGHT TRAINS Marking Devices § 221.14 Marking devices. (a) As prescribed in § 221.13, passenger, commuter and freight trains shall be... and commuter trains in compliance with paragraph (a) of this section shall be lighted under...

  13. 49 CFR 178.318-3 - Marking.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Marking. 178.318-3 Section 178.318-3 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY... Containers for Motor Vehicle Transportation § 178.318-3 Marking. Each container must be marked as...

  14. 49 CFR 178.318-3 - Marking.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Marking. 178.318-3 Section 178.318-3 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY... Containers for Motor Vehicle Transportation § 178.318-3 Marking. Each container must be marked as...

  15. 49 CFR 178.318-3 - Marking.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Marking. 178.318-3 Section 178.318-3 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY... Containers for Motor Vehicle Transportation § 178.318-3 Marking. Each container must be marked as...

  16. 49 CFR 178.318-3 - Marking.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Marking. 178.318-3 Section 178.318-3 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY... Containers for Motor Vehicle Transportation § 178.318-3 Marking. Each container must be marked as...

  17. Classroom Mark-Recapture with Crickets

    ERIC Educational Resources Information Center

    Whiteley, Andrew R.; Woolfe, Jennifer; Kennedy, Kathleen; Oberbillig, David; Brewer, Carol

    2007-01-01

    Mark-recapture techniques are commonly used by ecologists to estimate abundance of naturally occurring animals and are an important component of ecology curricula. This investigation teaches a mark-recapture technique using store-bought crickets in 10-gallon aquaria and provides an inexpensive way to teach students about mark-recapture in a real…

  18. 46 CFR 134.160 - Freeboard markings.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Freeboard markings. 134.160 Section 134.160 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OFFSHORE SUPPLY VESSELS ADDED PROVISIONS FOR LIFTBOATS § 134.160 Freeboard markings. Freeboard markings required by § 174.260 of this subchapter must...

  19. 46 CFR 134.160 - Freeboard markings.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Freeboard markings. 134.160 Section 134.160 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OFFSHORE SUPPLY VESSELS ADDED PROVISIONS FOR LIFTBOATS § 134.160 Freeboard markings. Freeboard markings required by § 174.260 of this subchapter must...

  20. 46 CFR 134.160 - Freeboard markings.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Freeboard markings. 134.160 Section 134.160 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OFFSHORE SUPPLY VESSELS ADDED PROVISIONS FOR LIFTBOATS § 134.160 Freeboard markings. Freeboard markings required by § 174.260 of this subchapter must...

  1. 46 CFR 134.160 - Freeboard markings.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Freeboard markings. 134.160 Section 134.160 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OFFSHORE SUPPLY VESSELS ADDED PROVISIONS FOR LIFTBOATS § 134.160 Freeboard markings. Freeboard markings required by § 174.260 of this subchapter must...

  2. 46 CFR 134.160 - Freeboard markings.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 4 2014-10-01 2014-10-01 false Freeboard markings. 134.160 Section 134.160 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OFFSHORE SUPPLY VESSELS ADDED PROVISIONS FOR LIFTBOATS § 134.160 Freeboard markings. Freeboard markings required by § 174.260 of this subchapter must...

  3. 48 CFR 752.7009 - Marking.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Marking. 752.7009 Section... SOLICITATION PROVISIONS AND CONTRACT CLAUSES Texts of USAID Contract Clauses 752.7009 Marking. The following clause is for use in all USAID contracts performed in whole or in part overseas. Marking (JAN 1993)...

  4. 48 CFR 752.7009 - Marking.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 5 2011-10-01 2011-10-01 false Marking. 752.7009 Section... SOLICITATION PROVISIONS AND CONTRACT CLAUSES Texts of USAID Contract Clauses 752.7009 Marking. The following clause is for use in all USAID contracts performed in whole or in part overseas. Marking (JAN 1993)...

  5. 14 CFR 25.1555 - Control markings.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Control markings. 25.1555 Section 25.1555....1555 Control markings. (a) Each cockpit control, other than primary flight controls and controls whose... aerodynamic control must be marked under the requirements of §§ 25.677 and 25.699. (c) For powerplant...

  6. 14 CFR 23.1555 - Control markings.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Control markings. 23.1555 Section 23.1555... Markings and Placards § 23.1555 Control markings. Link to an amendment published at 76 FR 75763, December 2, 2011. (a) Each cockpit control, other than primary flight controls and simple push button type...

  7. 14 CFR 25.1555 - Control markings.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Control markings. 25.1555 Section 25.1555....1555 Control markings. (a) Each cockpit control, other than primary flight controls and controls whose... aerodynamic control must be marked under the requirements of §§ 25.677 and 25.699. (c) For powerplant...

  8. 14 CFR 27.1555 - Control markings.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Control markings. 27.1555 Section 27.1555... Control markings. (a) Each cockpit control, other than primary flight controls or control whose function... fuel controls— (1) Each fuel tank selector control must be marked to indicate the...

  9. 7 CFR 160.32 - Marking containers.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Marking containers. 160.32 Section 160.32 Agriculture... STANDARDS FOR NAVAL STORES Analysis, Inspection, and Grading on Request § 160.32 Marking containers. The interested person shall provide any labor necessary for marking the containers, after the contents have...

  10. Marking Student Programs Using Graph Similarity

    ERIC Educational Resources Information Center

    Naude, Kevin A.; Greyling, Jean H.; Vogts, Dieter

    2010-01-01

    We present a novel approach to the automated marking of student programming assignments. Our technique quantifies the structural similarity between unmarked student submissions and marked solutions, and is the basis by which we assign marks. This is accomplished through an efficient novel graph similarity measure ("AssignSim"). Our experiments…

  11. 27 CFR 28.123 - Export marks.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Export marks. 28.123..., or Transportation to a Manufacturing Bonded Warehouse § 28.123 Export marks. (a) General. In addition... filled under the provisions of part 24 of this chapter, the proprietor shall mark the word “Export”...

  12. 27 CFR 28.223 - Export marks.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Export marks. 28.223... Export marks. In addition to the marks and brands required to be placed on kegs, barrels, cases, crates... “Export” on each container or case before removal for export, for use on vessels or aircraft, or...

  13. 27 CFR 28.216 - Export marks.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Export marks. 28.216... Export marks. In addition to the marks and brands required to be placed on packages or other bulk... “Export” on the Government side of each case or Government head of each container before removal...

  14. 46 CFR 111.25-5 - Marking.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Marking. 111.25-5 Section 111.25-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING ELECTRIC SYSTEMS-GENERAL REQUIREMENTS Motors § 111.25-5 Marking. (a) Each motor must have a marking or nameplate that meets either Section...

  15. 46 CFR 111.25-5 - Marking.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Marking. 111.25-5 Section 111.25-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING ELECTRIC SYSTEMS-GENERAL REQUIREMENTS Motors § 111.25-5 Marking. (a) Each motor must have a marking or nameplate that meets either Section...

  16. 46 CFR 111.25-5 - Marking.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Marking. 111.25-5 Section 111.25-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING ELECTRIC SYSTEMS-GENERAL REQUIREMENTS Motors § 111.25-5 Marking. (a) Each motor must have a marking or nameplate that meets either Section...

  17. 46 CFR 111.25-5 - Marking.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Marking. 111.25-5 Section 111.25-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING ELECTRIC SYSTEMS-GENERAL REQUIREMENTS Motors § 111.25-5 Marking. (a) Each motor must have a marking or nameplate that meets either Section...

  18. 46 CFR 111.25-5 - Marking.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 4 2014-10-01 2014-10-01 false Marking. 111.25-5 Section 111.25-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING ELECTRIC SYSTEMS-GENERAL REQUIREMENTS Motors § 111.25-5 Marking. (a) Each motor must have a marking or nameplate that meets either Section...

  19. 49 CFR 221.14 - Marking devices.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Marking devices. 221.14 Section 221.14 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION REAR END MARKING DEVICE-PASSENGER, COMMUTER AND FREIGHT TRAINS Marking...

  20. The Text Marking Patterns of College Students.

    ERIC Educational Resources Information Center

    Nist, Sherrie L.; Kirby, Katie

    1989-01-01

    Examines patterns in college students' text markings using texts from three content areas: history, political science, and sociology. Indicates little differential marking between various text-types. Concludes that students seem to have little idea how to mark text efficiently. (MG)

  1. 32 CFR 2001.25 - Declassification markings.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 32 National Defense 6 2014-07-01 2014-07-01 false Declassification markings. 2001.25 Section 2001.25 National Defense Other Regulations Relating to National Defense INFORMATION SECURITY OVERSIGHT... Identification and Markings § 2001.25 Declassification markings. (a) General. A uniform security...

  2. 32 CFR 2001.25 - Declassification markings.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 6 2010-07-01 2010-07-01 false Declassification markings. 2001.25 Section 2001.25 National Defense Other Regulations Relating to National Defense INFORMATION SECURITY OVERSIGHT... Identification and Markings § 2001.25 Declassification markings. (a) General. A uniform security...

  3. 32 CFR 2001.25 - Declassification markings.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 32 National Defense 6 2013-07-01 2013-07-01 false Declassification markings. 2001.25 Section 2001.25 National Defense Other Regulations Relating to National Defense INFORMATION SECURITY OVERSIGHT... Identification and Markings § 2001.25 Declassification markings. (a) General. A uniform security...

  4. 32 CFR 2001.25 - Declassification markings.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 32 National Defense 6 2012-07-01 2012-07-01 false Declassification markings. 2001.25 Section 2001.25 National Defense Other Regulations Relating to National Defense INFORMATION SECURITY OVERSIGHT... Identification and Markings § 2001.25 Declassification markings. (a) General. A uniform security...

  5. 32 CFR 2001.25 - Declassification markings.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 32 National Defense 6 2011-07-01 2011-07-01 false Declassification markings. 2001.25 Section 2001.25 National Defense Other Regulations Relating to National Defense INFORMATION SECURITY OVERSIGHT... Identification and Markings § 2001.25 Declassification markings. (a) General. A uniform security...

  6. 40 CFR 262.32 - Marking.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... APPLICABLE TO GENERATORS OF HAZARDOUS WASTE Pre-Transport Requirements § 262.32 Marking. (a) Before transporting or offering hazardous waste for transportation off-site, a generator must mark each package of... transportation off-site, a generator must mark each container of 119 gallons or less used in such...

  7. 40 CFR 262.32 - Marking.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... APPLICABLE TO GENERATORS OF HAZARDOUS WASTE Pre-Transport Requirements § 262.32 Marking. (a) Before transporting or offering hazardous waste for transportation off-site, a generator must mark each package of... transportation off-site, a generator must mark each container of 119 gallons or less used in such...

  8. 40 CFR 262.32 - Marking.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... APPLICABLE TO GENERATORS OF HAZARDOUS WASTE Pre-Transport Requirements § 262.32 Marking. (a) Before transporting or offering hazardous waste for transportation off-site, a generator must mark each package of... transportation off-site, a generator must mark each container of 119 gallons or less used in such...

  9. 40 CFR 262.32 - Marking.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... APPLICABLE TO GENERATORS OF HAZARDOUS WASTE Pre-Transport Requirements § 262.32 Marking. (a) Before transporting or offering hazardous waste for transportation off-site, a generator must mark each package of... transportation off-site, a generator must mark each container of 119 gallons or less used in such...

  10. 40 CFR 262.32 - Marking.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... APPLICABLE TO GENERATORS OF HAZARDOUS WASTE Pre-Transport Requirements § 262.32 Marking. (a) Before transporting or offering hazardous waste for transportation off-site, a generator must mark each package of... transportation off-site, a generator must mark each container of 119 gallons or less used in such...

  11. Lipopolysaccharide-induced hypothermia and hypotension are associated with inflammatory signaling that is triggered outside the brain.

    PubMed

    Al-Saffar, Hiba; Lewis, Kevin; Liu, Elaine; Schober, Alexandra; Corrigan, Joshua J; Shibata, Keita; Steiner, Alexandre A

    2013-02-01

    Little is known about the neuroimmune mechanisms responsible for the switch from fever to hypothermia observed in severe forms of systemic inflammation. We evaluated whether bacterial lipopolysaccharide (LPS) acting directly on the brain could promote a fever-hypothermia switch as well as the hypotension that is often associated with hypothermia in models of systemic inflammation. At an ambient temperature of 22°C, freely moving rats received intracerebroventricular (i.c.v.) injections of LPS at doses ranging from 0.5 to 25μg. Despite the use of such high doses, the prevailing thermal response was fever. To investigate if a hypothermic response could be hidden within the prevailing febrile response, rats were pretreated with a cyclooxygenase-2 inhibitor (SC-236, 3.5mg/kg i.v.) known to block fever, but this strategy also failed to reveal any consistent hypothermic response following i.c.v. LPS. At the doses tested, i.c.v. LPS was similarly ineffective at inducing hypotension. Additional doses of LPS did not need to be tested because the 25-μg dose was already sufficient to induce both hypothermia and hypotension when administered peripherally (intra-arterially). An empirical 3D model of the interplay among body temperature, arterial pressure and heart rate following intra-arterial LPS reinforced the strong association of hypothermia with hypotension and, at the same time, exposed a bell-shaped relationship between heart rate and body temperature. In summary, the present study demonstrates that hypothermia and hypotension are triggered exclusively by LPS acting outside the brain and provides an integrated model of the thermal and cardiovascular responses to peripheral LPS.

  12. Efficacy of prophylactic intramuscular ephedrine in prevention of hypotension during caesarean section under spinal anaesthesia: a comparative study.

    PubMed

    Bhar, Debasish; Bharati, Saswata; Halder, Partha Sarathi; Mondal, Subrata; Sarkar, Malay; Jana, Swapan

    2011-05-01

    Hypotension during caesarean section under spinal anaesthesia is a common complication. Several measures are used to reduce the incidence of hypotension but no method is fully effective. Prophylactic intramuscular ephedrine may be effective in reducing the incidence of hypotension in addition to conventional measures. To evaluate the efficacy of prophylactic intramuscular (IM) ephedrine (0.5 mg/kg, maximum up to 45 mg), given 10 minutes and 20 minutes before spinal anaesthesia to prevent hypotension, and to observe the adverse effects of IM ephedrine. A prospective, randomised, double-blind controlled study was undertaken where 150 pregnant mothers aged between 18 and 29 years and belonging to ASA physical status I, posted for elective caesarean section, were randomly allocated into one of the three groups. Group C received only preloading with 15 ml/kg of Ringer lactate (RL) solution, group E10 and group E20 received injection ephedrine 0.5 mg/kg IM 10 minutes and 20 minutes prior to performing spinal anaesthesia respectively along with 15 ml/kg RL preloading. The incidence of hypotension was significantly more in group C compared to other two groups. Mean arterial pressure and heart rate were significantly more in group E10 compared to group C. No significant increase in the incidence of hypertension and tachycardia in any group were observed. The findings of this study indicate that prophylactic IM ephedrine 0.5 mg/kg given 10 minutes before spinal anaesthesia gives better haemodynamic stability during intra-operative period without any significant increase in the incidence of adverse effects.

  13. Standards and practices for bite mark photography.

    PubMed

    Golden, G S

    2011-12-01

    In most crimes where bite marks are discovered, photographic accuracy is crucial to the investigative process since in many instances the bite mark(s) may be the only evidence linking a particular suspect to the crime. Therefore, the rationale for employing superior photographic principles is mandatory for the investigation team. This paper will discuss current standards, best practice, and armamentaria for digital photography of bite mark injuries on skin. Full spectrum protocols will be described including Alternate Light Imaging, Reflective Ultra-violet, and Infrared techniques for photo-documentation of images of bite marks and other bruise patterns that have been inflicted on human skin.

  14. The Mark 5C VLBI Data System

    NASA Technical Reports Server (NTRS)

    Whitney, Alan; Ruszczyk, Chester; Romney, Jon; Owens, Ken

    2010-01-01

    The Mark 5C disk-based VLBI data system is being developed as the third-generation Mark 5 disk-based system, increasing the sustained data-recording rate capability to 4 Gbps. It is built on the same basic platform as the Mark 5A, Mark 5B and Mark 5B+ systems and will use the same 8-disk modules as earlier Mark 5 systems, although two 8-disk modules will be necessary to support the 4 Gbps rate. Unlike its earlier brethren, which use proprietary data interfaces, the Mark 5C will accept data from a standard 10 Gigabit Ethernet connection and be compatible with the emerging VLBI Data Interchange Format (VDIF) standard. Data sources for the Mark 5C system will be based on new digital backends now being developed, specifically the RDBE in the U.S. and the dBBC in Europe, as well as others. The Mark 5C system is being planned for use with the VLBI2010 system and will also be used by NRAO as part of the VLBA sensitivity upgrade program; it will also be available to the global VLBI community from Conduant. Mark 5C system specification and development is supported by Haystack Observatory, NRAO, and Conduant Corporation. Prototype Mark 5C systems are expected in early 2010.

  15. Overlap of Post-obstructive Diuresis and Unmasked Diabetes Insipidus in a Case of IgG4-related Retroperitoneal Fibrosis and Tuberoinfundibular Hypophysitis: A Case Report and Review of the Literature

    PubMed Central

    Sasaki Yatabe, Midori; Watanabe, Kimio; Hayashi, Yoshimitsu; Yatabe, Junichi; Morimoto, Satoshi; Ichihara, Atsuhiro; Nakayama, Masaaki; Watanabe, Tsuyoshi

    2017-01-01

    The clinical picture of IgG4-related disease (IgG4-RD) is diverse because various organs can be affected. We describe the case of a 56-year-old man with acute renal failure and tuberoinfundibular hypophysitis due to IgG4-RD. Steroid therapy lowered the serum IgG4 level and ameliorated renal dysfunction, bilateral hydronephrosis and retroperitoneal fibrosis. However, polyuria from post-obstructive diuresis and unmasked central diabetes insipidus ensued. The patient's polyuria continued despite the administration of a therapeutic dose of glucocorticoid; the patient's pituitary swelling and anterior pituitary dysfunction were partially ameliorated. The pituitary swelling recurred seven months later. In patients with IgG4-RD, the manifestation of polyuria after steroid therapy should prompt suspicion of post-obstructive diuresis and the unmasking of central diabetes insipidus. PMID:28049999

  16. Overlap of Post-obstructive Diuresis and Unmasked Diabetes Insipidus in a Case of IgG4-related Retroperitoneal Fibrosis and Tuberoinfundibular Hypophysitis: A Case Report and Review of the Literature.

    PubMed

    Sasaki Yatabe, Midori; Watanabe, Kimio; Hayashi, Yoshimitsu; Yatabe, Junichi; Morimoto, Satoshi; Ichihara, Atsuhiro; Nakayama, Masaaki; Watanabe, Tsuyoshi

    The clinical picture of IgG4-related disease (IgG4-RD) is diverse because various organs can be affected. We describe the case of a 56-year-old man with acute renal failure and tuberoinfundibular hypophysitis due to IgG4-RD. Steroid therapy lowered the serum IgG4 level and ameliorated renal dysfunction, bilateral hydronephrosis and retroperitoneal fibrosis. However, polyuria from post-obstructive diuresis and unmasked central diabetes insipidus ensued. The patient's polyuria continued despite the administration of a therapeutic dose of glucocorticoid; the patient's pituitary swelling and anterior pituitary dysfunction were partially ameliorated. The pituitary swelling recurred seven months later. In patients with IgG4-RD, the manifestation of polyuria after steroid therapy should prompt suspicion of post-obstructive diuresis and the unmasking of central diabetes insipidus.

  17. Endogenous central histamine-induced reversal of critical hemorrhagic hypotension in rats: studies with L-histidine.

    PubMed

    Jochem, Jerzy

    2003-10-01

    Activation of the histaminergic system is characteristic of response to the action of adverse or potentially dangerous stimuli that disturb circulatory homeostasis, such as dehydration and changes in blood pressure. Previous study demonstrates that inhibition of histamine N-methyltransferase, which catabolizes histamine released from neurons, leads to the increase in endogenous central histamine concentrations and to the reversal of critical hemorrhagic hypotension. In the present study, the influence of intraperitoneal loading with histamine precursor L-histidine on central cardiovascular regulation was studied in a model of irreversible pressure-controlled hemorrhagic shock. Experiments were carried out in male Wistar rats anesthetized with ketamine/xylazine subjected to critical hemorrhagic hypotension of 20 to 25 mmHg, which resulted in the death of all control saline-treated animals within 30 min. L-histidine administered in 5 min of critical hypotension produced dose-dependent increases in mean arterial pressure and heart rate (100-500 mg/kg), and a 100% survival rate of 2 h (500 mg/kg), whereas in normotensive animals, it did not influence cardiovascular parameters. The resuscitating effect of L-histidine (500 mg/kg) was associated with increases in histamine concentrations in the cerebral cortex (0.97 +/- 0.11 nmol/g of wet tissue vs. 0.67 +/- 0.22 nmol/g of wet tissue; P<0.05), hypothalamus (4.78 +/- 0.58 nmol/g of wet tissue vs. 4.08 +/- 0.43 nmol/g of wet tissue; P<0.01), and medulla oblongata (0.55 +/- 0.18 nmol/g of wet tissue vs. 0.34 +/- 0.09 nmol/g of wet tissue; P<0.05), as well as with no changes in plasma histamine concentrations in comparison with the saline-treated group 20 min after injection. Pretreatment with (S)-alpha-fluoromethylhistidine (alpha-FMH, 0.5 mg intracerebroventricularly), an irreversible inhibitor of L-histidine decarboxylase, produced a decrease in central histamine concentrations and diminished volumes of blood required to

  18. Cerebral perfusion pressure directed therapy following traumatic brain injury and hypotension in swine.

    PubMed

    Malhotra, Ajai K; Schweitzer, John B; Fox, Jerry L; Fabian, Timothy C; Proctor, Kenneth G

    2003-09-01

    There is a paucity of studies, clinical and experimental, attesting to the benefit of cerebral perfusion pressure (CPP) directed pressor therapy following traumatic brain injury (TBI). The current study evaluates this therapy in a swine model of TBI and hypotension. Forty-five anesthetized and ventilated swine received TBI followed by a 45% blood volume bleed. After 1 h, all animals were resuscitated with 0.9% sodium chloride equal to three times the shed blood volume. The experimental group (PHE) received phenylephrine to maintain CPP > 80 mm Hg; the control group (SAL) did not. Outcomes in the first phase (n = 33) of the study were as follows: cerebro-venous oxygen saturation (S(cv)O(2)), cerebro-vascular carbon dioxide reactivity (DeltaS(cv)O(2)), and brain structural damage (beta-amyloid precursor protein [betaAPP] immunoreactivity). In the second phase (n = 12) of the study, extravascular blood free water (EVBFW) was measured in the brain and lung. After resuscitation, intracranial and mean arterial pressures were >15 and >80 mm Hg, respectively, in both groups. CPP declined to 64 +/- 5 mm Hg in the SAL group, despite fluid supplements. CPP was maintained at >80 mm Hg with pressors in the PHE group. PHE animals maintained better S(cv)O(2) (p < 0.05 at 180, 210, 240, 270, and 300 min post-TBI). At baseline, 5% CO(2) evoked a 16 +/- 4% increase in S(cv)O(2), indicating cerebral vasodilatation and luxury perfusion. By 240 min, this response was absent in SAL animals and preserved in PHE animals (p < 0.05). Brain EVBFW was higher in SAL animals; however, lung EVBFW was higher in PHE animals. There was no difference in betaAPP immunoreactivity between the SAL and PHE groups (p > 0.05). In this swine model of TBI and hypotension, CPP directed pressor therapy improved brain oxygenation and maintained cerebro-vascular CO(2) reactivity. Brain edema was lower, but lung edema was greater, suggesting a higher propensity for pulmonary complications.

  19. Cardiovascular regulation by central adrenergic mechanisms and its alteration by hypotensive drugs.

    PubMed

    Haeusler, G

    1975-06-01

    Electrical stimulation of the posterior hypothalamus is followed by an immediate increase in sympathetic nerve activity and rise in blood pressure. Destruction of hypothalamic adrenergic structures by local unilateral injection of 6-hydroxydopamine into the posterior hypothalamus reduced the blood pressure rise in response to stimulation of the lesioned side. This and numerous other findings indicate an involvement of central adrenergic neurons in the mediation of an increase of sympathetic nerve activity caused by hypothalamic stimulation. However, central adrenergic neurons do not seem to be an integral part of the sympathoexcitatory pathways originating in the posterior hypothalamus but rather facilitate their activation: after almost complete norepinephrine depletion produced by combined treatment with reserpine and alpha-methl-p-tyrosine, hypothalamic stimulation was still followed by an increase in spontaneous sympathetic nerve activity. Stimulation of an alpha-adrenoceptive site, probably located in the lower brain stem, mimics an activation of the baroreceptor reflex. The hypotensive drug, clonidine, stimulates this alpha-adrenoceptive site. In low doses clonidine facilitates the activation of the reflex, and in high doses this drug induces a state which closely resembles a pronounced activation of the reflex. Experiments following depletion of norepinephrine suggest that the central part of the baroreceptor reflex arc does not contain adrenergic neurons. However, these findings are compatible with the view that some neurons within the reflex arc are supplied with alpha-adrenoceptors. For the present it cannot be stated with certainty whether these alpha-adrenoceptors possess an innervation by adrenergic neurons projecting onto the reflex arc. In favor of such an innervation are the obsevations that alpha-methyldopa has its site of action in the lower brain stem and that the integrity of central adrenergic neurons is essential for its hypotensive effect. It

  20. Epidural Blood Patch Performed for Severe Intracranial Hypotension Following Lumbar Cerebrospinal Fluid Drainage for Intracranial Aneurysm Surgery. Retrospective Series and Literature Review

    PubMed Central

    Tanweer, Omar; Kalhorn, Stephen P.; Snell, Jamaal T.; Lieber, Bryan A.; Agarwal, Nitin; Huang, Paul P.; Sutin, Kenneth M.

    2015-01-01

    Intracranial hypotension (IH) can occur following lumbar drainage for clipping of an intracranial aneurysm. We observed 3 cases of IH, which were all successfully treated by epidural blood patch (EBP). Herein, the authors report our cases. PMID:27065093

  1. Use of Respiratory Impedance in Prehospital Care of Hypotensive Patients Associated with Hemorrhage and Trauma: A Case Series

    DTIC Science & Technology

    2012-01-01

    Use of respiratory impedance in prehospital care of hypotensive patients associated with hemorrhage and trauma: A case series Victor A. Convertino...J.Z., D.L.), Toledo , Ohio; Cypress Creek Emergency Medical Services (K.T., L.V.), Spring, Texas; Em- press EmergencyMedical Services (D.B.), Yonkers...Minneapolis, Minnesota. Address for reprints: Victor A. Convertino, PhD, United States Army Institute of Surgical Research, 3698 Chambers Pass, Fort Sam

  2. Spacelab life sciences flight experiments - An integrated approach to the study of cardiovascular deconditioning and orthostatic hypotension

    NASA Technical Reports Server (NTRS)

    Gaffney, F. A.

    1985-01-01

    A Spacelab experiment to study cardiovascular deconditioning and orthostatic hypotension is proposed. Previous experiments that have attempted to explain the factors which cause alterations in cardiovascular regulation are investigated. Based on these observations a hypothesis which states cephalad fluid shift produces cardiovascular changes is studied. The testing of the hypothesis is to include the analysis of physiological and anatomical changes in humans and animals for preflight and in-flight periods. The procedures and measurement techniques for the experiment are described.

  3. Transient A-V dissociation and severe hypotension due to consumption of Ayurvedic medicine--Vatsanabha (aconitum ferox).

    PubMed

    Laddhad, Deepak; Sancheti, Saurabh R; Dinde, Yogita

    2014-05-01

    A 24 year old married, well educated, female patient presented with complaints of giddiness and blackouts. On evaluation, patient had hypotension and bradycardia. ECG findings were suggestive of complete A-V dissociation. On detailed history patient revealed consumption. of Ayurvedic medicine Vatsanabha for arthritis. This study impresses upon the need for complete history talking and generating awareness regarding the correct and observed use of any drug including alternative medicines.

  4. Effect of meal size on post-prandial blood pressure and on postural hypotension in primary autonomic failure.

    PubMed

    Puvi-Rajasingham, S; Mathias, C J

    1996-04-01

    In chronic autonomic failure, food ingestion causes a profound and rapid fall in supine blood pressure and aggravates postural hypotension. Food volume and caloric load are important determinants of gastric emptying and postprandial splanchnic hyperaemia, which appears to be a major contributor to hypotension. We therefore compared the cardiovascular effects of three large meals with six small meals providing an identical daily caloric intake, in seven subjects with primary autonomic failure. Daytime ambulatory blood pressure (BP) was measured by Spacelabs 90207 every 30 min with additional recordings while lying, sitting and standing, 30 min after each meal. Systolic and diastolic BP were lower in all three positions after large meals; systolic 131 versus 151 mmHg (large versus small), p = 0.005, 109 versus 124 mmHg, 89 versus 103 mmHg and diastolic 76 versus 90 mmHg, p = 0.02, 66 versus 78 mmHg, p = 0.07 and 50 versus 66 mmHg, p = 0.06 for lying, sitting and standing, respectively. Between meals, BP fell to lower levels with large meals, 88 (20) mmHg versus 104 (19) mmHg, p = 0.002 and 48 (13) mmHg versus 63 (13), p = 0.0001 mmHg for systolic and diastolic pressure respectively. Five subjects had more symptoms of postural dizziness after large meals. In primary autonomic failure, smaller and more frequent meals reduce postprandial hypotension and diminish postural symptoms post-meal. This is likely to be a useful non-pharmacological method in the management of postprandial hypotension.

  5. Orthostatic hypotension is associated with decreased cerebrospinal fluid levels of chromogranin A in early stage of Parkinson disease.

    PubMed

    Kaiserova, Michaela; Prikrylova Vranova, Hana; Galuszka, Jan; Stejskal, David; Mensikova, Katerina; Zapletalova, Jana; Mares, Jan; Kanovsky, Petr

    2015-10-01

    An association between the CSF chromogranin A (CgA) and orthostatic blood pressure changes was investigated in 20 patients in the early stage of Parkinson disease (PD). There was a positive correlation between the CSF CgA and diastolic blood pressure change, when CSF CgA levels were lower in patients with orthostatic hypotension (OH). Decreased CSF CgA may be useful in predicting OH in the early stage of PD.

  6. Orthostatic Hypotension in Young Adults with and without Posttraumatic Stress Disorder

    PubMed Central

    Oddone, Ania E.; Dennis, Paul A.; Calhoun, Patrick S.; Watkins, Lana L.; Sherwood, Andrew; Dedert, Eric A.; Green, Kimberly T.; Stein, Jacob N.; Dennis, Michelle F.; Beckham, Jean C.

    2015-01-01

    OBJECTIVE The purpose of this research is (1) to evaluate differences in orthostatic hypotension (OH) among young adults with and without posttraumatic stress disorder (PTSD) and (2) to examine whether group differences may be attributable to behavioral risk factors frequently associated with PTSD. METHOD Volunteers and U.S. veterans 18–39 years old (n = 222) completed a semi-structured interview assessment of PTSD status. Direct measurements were obtained for supine and standing systolic and diastolic blood pressure at study visits as well as height and weight, from which body-mass index (BMI) was calculated. RESULTS After controlling for use of psychotropic medications, a logistic regression model revealed that PTSD status was positively associated with OH, such that participants with PTSD were at 4.51 greater odds of having OH than control participants. Moreover, this effect was partially mediated by lifetime alcohol dependence (bootstrapped 95% CI: −0.83 to −0.20). CONCLUSIONS Overall, PTSD may pose a significant risk for OH amongst younger adults. In the present sample, this relationship was primarily driven by the disproportionately high history of alcohol dependence amongst individuals with PTSD. These results suggest that traditional therapy for PTSD be coupled with treatment for alcohol dependency where applicable to reap both psychological and physiological benefits. PMID:25961117

  7. Sulfide toxicity: Mechanical ventilation and hypotension determine survival rate and brain necrosis

    SciTech Connect

    Baldelli, R.J.; Green, F.H.Y.; Auer, R.N. )

    1993-09-01

    Occupational exposure to hydrogen sulfide is one of the leading causes of sudden death in the workplace, especially in the oil and gas industry. High-dose exposure causes immediate neurogenic apnea and death; lower doses cause [open quotes]knockdown[close quotes] (transient loss of consciousness, with apnea). Because permanent neurological sequelae have been reported, the authors sought to determine whether sulfide can directly kill central nervous system neurons. Ventilated and unventilated rats were studied to allow administration of higher doses of sulfide and to facilitate physiological monitoring. It was extremely difficult to produce cerebral necrosis with sulfide. Only one of eight surviving unventilated rats given high-dose sulfide (a dose that was lethal in [ge]50% of animals) showed cerebral necrosis. Mechanical ventilation shifted the dose that was lethal in 50% of the animals to 190 mg/kg from 94 mg/kg in the unventilated rats. Sulfide was found to potently depress blood pressure. Cerebral necrosis was absent in the ventilated rats (n = 11), except in one rat that showed profound and sustained hypotension to [le]35 Torr. Electroencephalogram activity ceased during exposure but recovered when the animals regained consciousness. The authors conclude that very-high-dose sulfide is incapable of producing cerebral necrosis by a direct histotoxic effect. 32 refs., 5 figs.

  8. Definition of hypotension and assessment of hemodynamics in the preterm neonate.

    PubMed

    Cayabyab, R; McLean, C W; Seri, I

    2009-05-01

    The complexity of postnatal cardiovascular transition has only recently been better appreciated in the very low birth weight neonate. As blood pressure in itself poorly represents systemic blood flow, especially when the fetal channels are open and the developmentally regulated vital organ assignment may not have been completed, efforts to measure systemic blood flow have resulted in a novel, yet incomplete, understanding of the principles and clinical relevance of cardiovascular adaptation during postnatal transition in this patient population. This article describes the definition of hypotension based on the principles of cardiovascular physiology, and reviews the tools available to the clinician and researcher at the bedside to examine the complex relationship among blood pressure, systemic and organ blood flow, and tissue oxygen delivery and oxygen demand in vital and non-vital organs in the very low birth weight neonate. Only after gaining an insight into these complex relationships and processes will we be able to design clinical trials of selected treatment modalities targeting relevant patient sub-populations for the management of neonatal cardiovascular compromise. Only clinical trials based on a solid understanding of developmental cardiovascular physiology tailored to the appropriate patient sub-population hold the promise of being effective and practical, and can lead to improvements in both hemodynamic parameters and clinically relevant outcome measures.

  9. Ocular hypotension, ocular toxicity, and neurotoxicity in response to marihuana extract and cannabidiol.

    PubMed

    Colasanti, B K; Brown, R E; Craig, C R

    1984-01-01

    Marihuana extract containing 21.3% delta-9-tetrahydrocannabinol (100 micrograms/hr), delta-9-tetrahydrocannabinol (20 micrograms/hr), cannabidiol (20 micrograms/hr), or the polyethylene glycol vehicle (1 microliter/hr) was delivered topically to cat eyes via osmotic minipumps over a 9-day period. Intraocular pressure differences between treated and untreated eyes of cats receiving marihuana extract remained 3-4 mmHg lower than those for vehicle controls, while differential values for the delta 9-THC-treated group remained reduced by 3-5 mmHg; data for these two groups did not differ statistically. Pressure differences between treated and untreated eyes of cats receiving cannabidiol were likewise 3-4 mmHg lower than values for controls. Ocular toxicity after delta 9-THC, consisting of conjunctival erythema and chemosis as well as corneal opacification, was quite severe. Although these changes also occurred after marihuana extract, their intensity was much reduced. In contrast, no ocular toxicity became apparent during administration of cannabidiol. While marihuana extract and delta 9-THC produced a dose-related increase in the appearance of 8-13 Hz polyspike discharges in the electrocorticograms of rats, both polyethylene glycol and cannabidiol lacked this effect. These results indicate that the ocular and central effects of marihuana extract and delta 9-THC are qualitatively similar. In addition, it appears that the ocular hypotensive effect produced by cannabidiol is relatively dissociable from both the ocular toxicity and the neurotoxicity associated with marihuana extract.

  10. Predictors of the Treatment Response of Spontaneous Intracranial Hypotension to an Epidural Blood Patch.

    PubMed

    Karm, Myong-Hwan; Choi, Jae-Hyung; Kim, Doohwan; Park, Jun Young; Yun, Hye Joo; Suh, Jeong Hun

    2016-05-01

    Spontaneous intracranial hypotension (SIH) is characterized by postural headache because of low cerebrospinal fluid (CSF) pressure. Brain magnetic resonance imaging (MRI) and radioisotope (RI) cisternography can be used to identify the site of a CSF leakage. Although autologous epidural blood patch (EBP) is a very effective treatment modality, some patients require a repeat autologous EBP. We investigated whether autologous EBP responses correlate with surrogate markers of quantitative findings.All cases of autologous EBP for SIH from January 2006 to December 2014 were enrolled. The demographic variables, number of EBPs, pain scores, RI cisternography (early visualization of bladder activity), and MRI findings (subdural fluid collections, pachymeningeal enhancement, engorgement of venous structures, pituitary hyperemia, and sagging of the brain) were reviewed.Patients with early bladder activity on RI cisternography had a tendency to need a higher number of autologous EBPs. Only sagging of the brain and no other variables showed a statistically significant negative correlation with the number of autologous EBPs.The response to autologous EBP may be related to the radiologic findings of early bladder activity on RI cisternography and sagging of the brain on MRI.

  11. Predictors of the Treatment Response of Spontaneous Intracranial Hypotension to an Epidural Blood Patch

    PubMed Central

    Karm, Myong-Hwan; Choi, Jae-Hyung; Kim, Doohwan; Park, Jun Young; Yun, Hye Joo; Suh, Jeong Hun

    2016-01-01

    Abstract Spontaneous intracranial hypotension (SIH) is characterized by postural headache because of low cerebrospinal fluid (CSF) pressure. Brain magnetic resonance imaging (MRI) and radioisotope (RI) cisternography can be used to identify the site of a CSF leakage. Although autologous epidural blood patch (EBP) is a very effective treatment modality, some patients require a repeat autologous EBP. We investigated whether autologous EBP responses correlate with surrogate markers of quantitative findings. All cases of autologous EBP for SIH from January 2006 to December 2014 were enrolled. The demographic variables, number of EBPs, pain scores, RI cisternography (early visualization of bladder activity), and MRI findings (subdural fluid collections, pachymeningeal enhancement, engorgement of venous structures, pituitary hyperemia, and sagging of the brain) were reviewed. Patients with early bladder activity on RI cisternography had a tendency to need a higher number of autologous EBPs. Only sagging of the brain and no other variables showed a statistically significant negative correlation with the number of autologous EBPs. The response to autologous EBP may be related to the radiologic findings of early bladder activity on RI cisternography and sagging of the brain on MRI. PMID:27149484

  12. Post-suspension hypotension is attenuated in Sprague-Dawley rats by prostacyclin synthase inhibition

    NASA Technical Reports Server (NTRS)

    Bayorh, M. A.; Eatman, D.; Walton, M.; Socci, R. R.; Emmett, N.

    2002-01-01

    Cardiovascular deconditioning, sometimes manifested in astronauts during standing postflight, may be related to the impairment of autonomic function and/or excessive production of endothelium-dependent relaxing factors. In the present study, we examined the cardiovascular responses to 7-day 30 degrees tail-suspension and a subsequent 6-h post-suspension period in conscious male Sprague-Dawley rats to determine the role of prostacyclin in the observed post-suspension reduction in mean arterial pressure (MAP). The specific prostacyclin synthase inhibitor U-51605 (0.3 mg/kg), or saline, was administered intravenously prior to release from suspension and at 2 and 4 h post-suspension. During 7 days of suspension, MAP did not change, however, there was a post-suspension reduction in MAP which was associated with significant increases in plasma prostacyclin and nitric oxide. U-51605 attenuated the observed post-suspension hypotension and reduced plasma prostacyclin levels, but not nitric oxide levels. The baroreflex sensitivity for heart rate was modified by U-51605: increased MAP threshold and effective MAP range. Thus, the post-suspension reduction in mean arterial pressure may be due to overproduction of prostacyclin and/or other endothelium-dependent relaxing factors and alteration in baroreflex activity.

  13. Indomethacin attenuates post-suspension hypotension in Sprague-Dawley rats

    NASA Technical Reports Server (NTRS)

    Bayorh, M. A.; Eatman, D.; Wang, M.; Socci, R. R.; Emmett, N.; Thierry-Palmer, M.

    2001-01-01

    Orthostatic hypotension is a serious condition that is sometimes manifested in astronauts during standing postflight. These observations may be related to impairment of autonomic function and/or excessive production of endothelium-dependent relaxing factors. To evaluate the role of the cyclooxygenase inhibitor indomethacin as a countermeasure against the post-suspension reduction in mean arterial pressure (MAP), we examined the cardiovascular responses to 7-day 30 degrees tail-suspension and a subsequent 6-hr post-suspension period in conscious male Sprague-Dawley rats. Indomethacin (2 mg/kg) or saline were administered intravenously prior to release from suspension and at 2 and 4 hrs post-suspension. Direct MAP and heart rate were determined prior to suspension, daily and every 2 hrs post-suspension. During suspension, MAP did not change, in contrast, during post-suspension; it decreased compared to parallel non-suspended, untreated animals. There were no significant changes in heart rate. The reduction in MAP post-suspension was associated with significant increases in plasma prostacyclin. Indomethacin attenuated the observed post-suspension reduction in MAP and reduced plasma prostacyclin levels. Also, the baroreflex sensitivity for heart rate was modified by indomethacin--the MAP threshold for baroreflex activation was raised and the effective MAP range expanded. Thus, the post suspension reduction in mean arterial pressure may be due to overproduction of vasodilatory prostaglandins and/or other endothelium-dependent relaxing factors and alteration in baroreflex activity.

  14. Refractory Orthostatic Hypotension Caused by a Recurrent Hemangioblastoma: Case Report and Review of the Literature

    PubMed Central

    Nangunoori, Raj; Singh, Anil; Aziz, Khaled

    2016-01-01

    Refractory orthostatic hypotension (OH) has been described following surgery for posterior fossa tumors. We present the case of a patient with refractory OH following attempted surgical resection. We also reviewed the available literature to describe pathophysiologic mechanisms for this rare entity. A 58-year-old female was found to have a hemangioblastoma at the cervicomedullary junction following workup for dysphagia and coordination difficulties. She underwent successful suboccipital craniotomy and gross total resection. However, the patient’s symptoms returned several years later and a magnetic resonance imaging (MRI) showed tumor recurrence. A surgical resection was attempted but could not be performed due to significant scarring. Following discharge, she returned to our care with severe syncopal episodes, refractory OH, and an inability to ambulate. Aggressive medical therapy resulted in a gradual improvement in her ability to ambulate and a reduction in her orthostatic episodes. Unfortunately she died due to sepsis from aspiration pneumonia several months later. A survey of the literature yielded a total of 10 reports (14 patients) with refractory OH as a result of tumors in the cervicomedullary region. Five of fourteen patients died from complications related to OH and brainstem compression while the remainder had some improvement and were discharged. Refractory OH can rarely be a presenting sign of a tumor in the cervicomedullary junction or can manifest following surgical resection of tumors in this region. Recognition of OH and the institution of medical therapy (sodium and fluid replacement) and pharmacotherapy may curb the significant morbidity associated with this condition. PMID:27158570

  15. Laboratory study on "intracranial hypotension" created by pumping the chamber of a hydrocephalus shunt

    PubMed Central

    Bromby, Adam; Czosnyka, Zofia; Allin, David; Richards, Hugh K; Pickard, John D; Czosnyka, Marek

    2007-01-01

    Background It has been reported that pumping a shunt in situ may precipitate a proximal occlusion, and/or lead to ventricular over-drainage, particularly in the context of small ventricles. In the laboratory we measured the effect of pumping the pre-chamber of hydrocephalus shunts on intracranial hypotension. Materials and methods A simple physical model of the CSF space in a hydrocephalic patient was constructed with appropriate compliance, CSF production and circulation. This was used to test eleven different hydrocephalus shunts. The lowest pressure obtained, the number of pumps needed to reach this pressure, and the maximum pressure change with a single pump, were recorded. Results All models were able to produce negative pressures ranging from -11.5 mmHg (Orbis-Sigma valve) to -233.1 mmHg (Sinu-Shunt). The number of pumps required reaching these levels ranged from 21 (PS Medical LP Reservoir) to 315 (Codman Hakim-Programmable). The maximum pressure change per pump ranged from 0.39 mmHg (Orbis-Sigma valve) to 23.1 (PS Medical LP Reservoir). Conclusion Patients, carers and professionals should be warned that 'pumping' a shunt's pre-chamber may cause a large change in intracranial pressure and predispose the patient to ventricular catheter obstruction or other complications. PMID:17386089

  16. Orthostatic hypotension: prevalence and associated risk factors among the ambulatory elderly in an Asian population

    PubMed Central

    Zhu, Qing Olivia; Tan, Choon Seng Gilbert; Tan, Hwee Leong; Wong, Ruining Geraldine; Joshi, Chinmaya Shrikant; Cuttilan, Ravi Amran; Sng, Gek Khim Judy; Tan, Ngiap Chuan

    2016-01-01

    INTRODUCTION The prevalence of orthostatic hypotension (OH) among the elderly population in Singapore, as defined by a decline in blood pressure upon a change in position, is not well-established. Studies associate OH with clinically significant outcomes such as falls. This study aims to determine the prevalence of OH among elderly patients attending a public primary care clinic (polyclinic) for chronic disease management, and examine the relationships between postulated risk factors and OH. METHODS Patients aged ≥ 65 years attending a typical polyclinic in Geylang were identified and targeted for recruitment at the study site. A questionnaire on symptoms and postulated risk factors was administered, followed by supine and standing blood pressure measurements. Cross-sectional analysis was performed with independent sample t-test for continuous data and chi-square test for categorical data. Prevalence rate ratios with 95% confidence interval were calculated for the latter. RESULTS A total of 364 multiethnic patients participated in the study. The prevalence of OH was 11.0%. Older age, comorbidities such as cardiac failure and kidney disease, being physically inactive at work, fatigue, self-reported dizziness in the past year, and the use of loop diuretics were found to be significantly associated with OH. CONCLUSION About one in ten elderly patients at a local polyclinic was affected by OH, which was associated with multiple factors. Some of these factors are modifiable and can be addressed to reduce the incidence of OH. PMID:27549316

  17. Cervical CT scan-guided epidural blood patches for spontaneous intracranial hypotension.

    PubMed

    Maingard, Julian; Giles, Lauren; Marriott, Mark; Phal, Pramit M

    2015-12-01

    We describe two patients with spontaneous intracranial hypotension (SIH), presenting with postural headache due to C1-C2 cerebrospinal fluid (CSF) leak. Both patients were refractory to lumbar epidural blood patching (EBP), and subsequently underwent successful CT scan-guided cervical EBP. SIH affects approximately 1 in 50,000 patients, with females more frequently affected. Its associated features are variable, and as such, misdiagnosis is common. Therefore, imaging plays an important role in the diagnostic workup of SIH and can include MRI of the brain and spine, CT myelogram, and radionuclide cisternography. In patients with an established diagnosis and confirmed CSF leak, symptoms will usually resolve with conservative management. However, in a select subgroup of patients, the symptoms are refractory to medical management and require more invasive therapies. In patients with cervical leaks, EBP in the cervical region is an effective management approach, either in close proximity to, or directly targeting a dural defect. CT scan-guided cervical EBP is an effective treatment approach in refractory SIH, and should be considered in those patients who are refractory to conservative management.

  18. Application of IHS criteria to headache attributed to spontaneous intracranial hypotension in a large population.

    PubMed

    Mea, E; Chiapparini, L; Savoiardo, M; Franzini, A; Grimaldi, D; Bussone, G; Leone, M

    2009-04-01

    We applied the recent International Headache Society (IHS) criteria for headache related to spontaneous intracranial hypotension (SIH) to 90 consecutive patients with a final diagnosis of SIH confirmed by cerebral magnetic resonance imaging with contrast. Orthostatic headache (developing within 2 h of standing or sitting up) was present in 67 patients (75%) but appeared within 15 min after standing or sitting-as required by point A of the criteria-in only 53 (59%). Forty-four (49%) patients did not satisfy point A, including 22 (24%) with non-orthostatic headache and 14 (16%) with headache developing >or= 15 min after standing or sitting up; 80 (89%) did not satisfy point D. Only three (3%) patients had headache fully satisfying the IHS criteria. These findings indicate that the current IHS criteria do not capture most patients with SIH-associated headache. Excluding the requirement for response to epidural blood patch (criterion D) and considering headaches appearing within 2 h of sitting or standing up would capture more patients.

  19. Hypotensive and vasorelaxant effects of citronellol, a monoterpene alcohol, in rats.

    PubMed

    Bastos, Joana F A; Moreira, Italo J A; Ribeiro, Thaís P; Medeiros, Isac A; Antoniolli, Angelo R; De Sousa, Damião P; Santos, Márcio R V

    2010-04-01

    Citronellol is an essential oil constituent from the medicinal plants Cymbopogon citratus, Cymbopogon winterianus and Lippia alba which are thought to possess antihypertensive properties. Citronellol-induced cardiovascular effects were evaluated in this study. In rats, citronellol (1-20 mg/kg, i.v.) induced hypotension, which was not affected by pre-treatment with atropine, hexamethonium, N(omega)-nitro-L-arginine methyl ester hydrochloride or indomethacin, and tachycardia, which was only attenuated by pre-treatment with atropine and hexamethonium. These responses were less than those obtained for nifedipine, a reference drug. In intact rings of rat mesenteric artery pre-contracted with 10 microM phenylephrine, citronellol induced relaxations (pD(2) = 0.71 +/- 0.11; E(max) = 102 +/- 5%; n = 6) that were not affected by endothelium removal, after tetraethylamonium in rings without endothelium pre-contracted with KCl 80 mM. Citronellol strongly antagonized (maximal inhibition = 97 +/- 4%; n = 6) the contractions induced by CaCl(2) (10(-6) to 3 x 10(-3 )M) and did not induce additional effects on the maximal response of nifedipine (10 microM). Finally, citronellol inhibited the contractions induced by 10 microM phenylephrine or 20 mM caffeine. The present results suggest that citronellol lowers blood pressure by a direct effect on the vascular smooth muscle leading to vasodilation.

  20. Postural hypotension and abnormalities of salt and water metabolism in myelopathy patients.

    PubMed

    Frisbie, J H; Steele, D J

    1997-05-01

    To describe the clinical manifestations of postural hypotension (PH) in myelopathy patients a standardized interview and chart review were carried out. Of 232 myelopathy patients with more than 2 years of paralysis seen during a 2 year period, 30 had been treated for PH. All PH patients were paralysed at levels higher than thoracic 7. The highest risk patients were tetraplegic, motor complete, 24 of 73 (33%). The common symptoms of PH were those of reduced consciousness (100%), strength (75%), vision (56%) and breath (53%). Precipitating factors were hot weather (77%) bowel care (33%) and meals (30%). Symptoms worsened with the duration of paralysis in 12 patients. Chronic hyponatremia was found in 54% of the PH patients and 16% of those without, P < 0.001. Of five PH-hyponatremic patients with urine sodium and osmolality determinations, five continued to retain water (> 150 mOsm/kg) while four failed to conserve salt (> 19 mmol Na/L). PH is common among myelopathy patients with higher levels of paralysis, symptoms are variable, and abnormal salt and water metabolism often coexist.

  1. Spontaneous intracranial hypotension: clinical and neuroimaging findings in six cases with literature review.

    PubMed

    Haritanti, A; Karacostas, D; Drevelengas, A; Kanellopoulos, V; Paraskevopoulou, E; Lefkopoulos, A; Economou, I; Dimitriadis, A S

    2009-02-01

    Spontaneous intracranial hypotension (SIH) is an uncommon but increasingly recognized syndrome. Orthostatic headache with typical findings on magnetic resonance imaging (MRI) are the key to diagnosis. Delayed diagnosis of this condition may subject patients to unnecessary procedures and prolong morbidity. We describe six patients with SIH and outline the important clinical and neuroimaging findings. They were all relatively young, 20-54 years old, with clearly orthostatic headache, minimal neurological signs (only abducent nerve paresis in two) and diffuse pachymeningeal gadolinium enhancement on brain MRI, while two of them presented subdural hygromas. Spinal MRI was helpful in detecting a cervical cerebrospinal fluid leak in three patients and dilatation of the vertebral venous plexus with extradural fluid collection in another. Conservative management resulted in rapid resolution of symptoms in five patients (10 days-3 weeks) and in one who developed cerebral venous sinus thrombosis, the condition resolved in 2 months. However, this rapid clinical improvement was not accompanied by an analogous regression of the brain MR findings that persisted on a longer follow-up. Along with recent literature data, our patients further point out that SIH, to be correctly diagnosed, necessitates increased alertness by the attending physician, in the evaluation of headaches.

  2. Resistance exercise training does not affect postexercise hypotension and wave reflection in women with fibromyalgia.

    PubMed

    Kingsley, J Derek; McMillan, Victor; Figueroa, Arturo

    2011-04-01

    The purpose of this study was to assess the effects of resistance exercise training (RET) on aortic wave reflection and hemodynamics during recovery from acute resistance exercise in women with fibromyalgia (FM) and healthy women (HW). Nine women with FM (aged 42 ± 5 years; mean ± SD) and 14 HW (aged 45 ± 5 years) completed testing at baseline and after 12 weeks of whole-body RET that consisted of 3 sets of 5 exercises. Heart rate (HR), digital blood pressure (BP, plethysmography), aortic BP, and wave reflection (radial tonometry) were assessed before and 20 min after acute leg resistance exercise. Aortic and digital diastolic blood pressure (DBP) were significantly decreased (p < 0.05) and aortic and digital pulse pressures (PP) were significantly increased (p < 0.05) after acute exercise before RET. Acute resistance exercise had no effect on HR, wave reflection (augmentation index and reflection time), digital, or aortic systolic BP. RET improved muscle strength without affecting acute DBP and PP responses. Acute resistance exercise produces postexercise diastolic hypotension without affecting systolic blood pressure, HR, and wave reflection responses in women with and without FM. RET does not alter resting and postexercise hemodynamics and aortic wave reflection in premenopausal women.

  3. Prediction of orthostatic hypotension in multiple system atrophy and Parkinson disease

    PubMed Central

    Sun, Zhanfang; Jia, Dandan; Shi, Yuting; Hou, Xuan; Yang, Xiaosu; Guo, Jifeng; Li, Nan; Wang, Junling; Sun, Qiying; Zhang, Hainan; Lei, Lifang; Shen, Lu; Yan, Xinxiang; Xia, Kun; Jiang, Hong; Tang, Beisha

    2016-01-01

    Orthostatic hypotension (OH) is common in multiple system atrophy (MSA) and Parkinson disease (PD), generally assessed through a lying-to-standing orthostatic test. However, standing blood pressure may not be available due to orthostatic intolerance or immobilization for such patients. Systolic blood pressure (SBP) and diastolic blood pressure (DBP) were successively measured in supine, sitting, and standing positions in patients with MSA and PD. Receiver operating characteristic analysis was used to evaluate diagnostic performance of the drops of sitting SBP or DBP. OH and severe OH were respectively regarded as “gold standard”. The drops of SBP in standing position were associated with increased disease severity for MSA and correlated with age for PD. In MSA group, drops in sitting SBP ≥ 14 mmHg or DBP ≥ 6 mmHg had highest validity for prediction of OH, and drops in sitting SBP ≥ 18 mmHg or DBP ≥ 8 mmHg for severe OH. In PD group, drops in sitting SBP ≥ 10 mmHg or DBP ≥ 6 mmHg had highest validity for prediction of OH. The lying-to-sitting orthostatic test is an alternative method for detection of OH in MSA and PD, especially when standing BP could not be validly measured due to various reasons. PMID:26867507

  4. Effects of carotid hypotension on aortic hemodynamics in the unanesthetized dog.

    PubMed

    Cox, R H; Fronek, A; Peterson, L H

    1975-11-01

    The effects of occlusion of the brachiocephalic artery on aortic hemodynamics were assessed in 12 chronically instrumented dogs in the unanesthetized state. Continuous measurements of ascending aorta pressure and flow were made. In the steady state following occlusion, heart rate increased by 36% and mean arterial pressure by 45%, while cardiac output was unchanged from preocclusion levels. Hydraulic power delivery to the systemic circulation by the left ventricle was increased during occlusion, while the fraction of total power associated with pulsations decreased. Values of peripheral resistance and ascending aorta input impedance were both increased during occlusion. Graded occlusions of the brachiocephalic artery produced graded, monotonic increases in the entire aortic impedance spectrum between 2 and 20 Hz with more sensitive responses occurring with the smaller, submaximal responses. Considered with results of previous studies, these results suggest that activation of smooth muscle in large conduit arteries is also associated with the pressor response which accompanies carotid hypotension and that such activation has a hemodynamically significant effect.

  5. Pharmacodynamic study on acute hypotensive activities of Carissa carandas extract in normal rats.

    PubMed

    Shamim, Sumbul; Ahmad, Syed Iqbal

    2012-07-01

    This study aims to evaluate the effect of Carissa carandas extract on cardiovascular function of normal rats. Intravenous bolus injection of this extract in the doses of 5 mg kg(-1)_-45 mg kg(-1), produced dose dependent reduction in arterial blood pressure (p<0.001). The 45mg/kg dose caused a 50.75% ± 2.71 decrease in MABP which was highly significant with P value < 0.0005 when compared with its controls. Significant reduction in heart rate frequency was observed after CC injection at a dose of 45 mg kg-1 (p<0.001). The results were comparable with Acetylcholine 10(-4) M. The receptor activity performed for which Atropine 10(-4)M was administered I.V. and then the extract (45mg/kg) was administered. A highly Non Significant fall in Mean Arterial Blood pressure was observed 1.51% ± 0.22 (P>0.05). It was concluded that the Carissa carandas Ethanol extract possess potent acute hypotensive effect in normal rats. It stimulates the muscarinic receptors located on the endothelial cells of the vasculature. This stimulation results in the release of endothelial-derived relaxing factors (EDRFs) or nitric oxide that diffuses to vasculature smooth muscles and causes their relaxation.

  6. A Review of Potential Marine-derived Hypotensive and Anti-obesity Peptides.

    PubMed

    Manikkam, V; Vasiljevic, T; Donkor, O N; Mathai, M L

    2016-01-01

    Bioactive peptides are food derived components, usually consisting of 3-20 amino acids, which are inactive when incorporated within their parent protein. Once liberated by enzymatic or chemical hydrolysis, during food processing and gastrointestinal transit, they can potentially provide an array of health benefits to the human body. Owing to an unprecedented increase in the worldwide incidence of obesity and hypertension, medical researchers are focusing on the hypotensive and anti-obesity properties of nutritionally derived bioactive peptides. The role of the renin-angiotensin system has long been established in the aetiology of metabolic diseases and hypertension. Targeting the renin-angiotensin system by inhibiting the activity of angiotensin-converting enzyme (ACE) and preventing the formation of angiotensin II can be a potential therapeutic approach to the treatment of hypertension and obesity. Fish-derived proteins and peptides can potentially be excellent sources of bioactive components, mainly as a source of ACE inhibitors. However, increased use of marine sources, poses an unsustainable burden on particular fish stocks, so, the underutilized fish species and by-products can be exploited for this purpose. This paper provides an overview of the techniques involved in the production, isolation, purification, and characterization of bioactive peptides from marine sources, as well as the evaluation of the ACE inhibitory (ACE-I) activity and bioavailability.

  7. [Management of transient radicular pain after receiving an epidural blood patch for headaches due to spontaneous intracranial hypotension].

    PubMed

    Melo, M C; Revuelta, M E; Santeularia, T; Genové, M; Català, E

    2015-11-01

    Spontaneous intracranial hypotension headache is an uncommon disease that resolves spontaneously in most of the cases and in a short period of time. The initial treatment should be symptomatic. In some patients the symptomatology is extremely disabling, and in these cases both the diagnosis and treatment may be performed by an epidural blood patch. A 49-year-old Caucasian woman, with no previous record of epidural or intrathecal puncture, consulted in the Emergency Department complaining of a 9-day history of frontal headache and diplopia, along with nausea and vomiting. The patient was diagnosed with spontaneous intracranial hypotension headache. Considering the symptomatology and the uncontrolled pain, the Pain Unit of our hospital performed an epidural blood patch. In the first 24h the patient reported a remarkable relief of both headache and diplopia but developed a left lumbar radiculopathy that was treated successfully with supportive measures. Transient lumbar radiculopathy is a common and acceptable event secondary to the use of epidural blood patch as a treatment for spontaneous intracranial hypotension headache.

  8. Prophylactic Phenylephrine Infusions to Reduce Severe Spinal Anesthesia Hypotension During Cesarean Delivery in a Resource-Constrained Environment.

    PubMed

    Bishop, David G; Cairns, Carel; Grobbelaar, Mariette; Rodseth, Reitze N

    2017-02-24

    Phenylephrine infusions are considered as standard management for obstetric spinal hypotension, but there remains reluctance to implement them in resource-limited contexts. This prospective, alternating intervention study of patients undergoing elective or urgent cesarean delivery under spinal anesthesia compared a vasopressor bolus strategy to fixed-rate, low-dose prophylactic phenylephrine infusion with supplemental boluses. The primary outcome was the incidence of severe hypotension (mean arterial pressure <70% baseline or systolic blood pressure <80 mm Hg). Fewer patients receiving prophylactic phenylephrine infusions had severe hypotension (47.4% [n = 120/253] vs 62.1% [n = 157/253], P = .001, estimated relative risk 0.84, 95% confidence interval 0.69-1.02), with no significant difference in the rate of hypertension (15% [n = 39/253] vs 11% [n = 27/253], P = .11, estimated relative risk 1.39, confidence interval 0.87-2.20). Guidelines for resource-constrained settings should consider a fixed, low-dose phenylephrine infusion in combination with rescue vasopressor bolus therapy.

  9. 7 CFR 51.311 - Marking requirements.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... STANDARDS) United States Standards for Grades of Apples Marking Requirements § 51.311 Marking requirements... minimum diameter of apples packed in a closed container shall be indicated on the container. For apple... varieties, the minimum diameter and minimum weight of apples packed in a closed container shall be...

  10. 7 CFR 51.311 - Marking requirements.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... STANDARDS) United States Standards for Grades of Apples Marking Requirements § 51.311 Marking requirements... minimum diameter of apples packed in a closed container shall be indicated on the container. For apple... varieties, the minimum diameter and minimum weight of apples packed in a closed container shall be...

  11. 7 CFR 51.311 - Marking requirements.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... STANDARDS) United States Standards for Grades of Apples Marking Requirements § 51.311 Marking requirements... minimum diameter of apples packed in a closed container shall be indicated on the container. For apple... varieties, the minimum diameter and minimum weight of apples packed in a closed container shall be...

  12. 46 CFR 160.031-6 - Marking.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Line-Throwing Appliance, Shoulder Gun Type (and Equipment) § 160.031-6 Marking. (a) Gun. The gun shall be permanently and legibly marked on the barrel with the manufacturer's model or type designation of the gun, the serial number for the gun, the official Coast...

  13. 46 CFR 160.031-6 - Marking.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Line-Throwing Appliance, Shoulder Gun Type (and Equipment) § 160.031-6 Marking. (a) Gun. The gun shall be permanently and legibly marked on the barrel with the manufacturer's model or type designation of the gun, the serial number for the gun, the official Coast...

  14. 46 CFR 160.031-6 - Marking.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Line-Throwing Appliance, Shoulder Gun Type (and Equipment) § 160.031-6 Marking. (a) Gun. The gun shall be permanently and legibly marked on the barrel with the manufacturer's model or type designation of the gun, the serial number for the gun, the official Coast...

  15. 46 CFR 160.031-6 - Marking.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Line-Throwing Appliance, Shoulder Gun Type (and Equipment) § 160.031-6 Marking. (a) Gun. The gun shall be permanently and legibly marked on the barrel with the manufacturer's model or type designation of the gun, the serial number for the gun, the official Coast...

  16. 46 CFR 160.031-6 - Marking.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Line-Throwing Appliance, Shoulder Gun Type (and Equipment) § 160.031-6 Marking. (a) Gun. The gun shall be permanently and legibly marked on the barrel with the manufacturer's model or type designation of the gun, the serial number for the gun, the official Coast...

  17. 14 CFR 27.1555 - Control markings.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... showing rotor pitch or landing gear position, must be marked so that each crewmember can determine at any... be marked as to method of operation. (e) For rotorcraft incorporating retractable landing gear, the maximum landing gear operating speed must be displayed in clear view of the pilot....

  18. 14 CFR 27.1555 - Control markings.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... showing rotor pitch or landing gear position, must be marked so that each crewmember can determine at any... be marked as to method of operation. (e) For rotorcraft incorporating retractable landing gear, the maximum landing gear operating speed must be displayed in clear view of the pilot....

  19. 46 CFR 160.053-5 - Marking.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 6 2012-10-01 2012-10-01 false Marking. 160.053-5 Section 160.053-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) EQUIPMENT, CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Work Vests, Unicellular Plastic Foam § 160.053-5 Marking....

  20. 46 CFR 160.053-5 - Marking.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 6 2011-10-01 2011-10-01 false Marking. 160.053-5 Section 160.053-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) EQUIPMENT, CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Work Vests, Unicellular Plastic Foam § 160.053-5 Marking....

  1. Credit Documentation and the Mark 15 Subroutine

    SciTech Connect

    McAllister, J.E.

    2001-08-16

    This report documents the rewrite of the heat transfer subroutine. Part of the process of preparing the Mark 15 assembly for production operation is the development of thermal-hydraulic limits for the assembly. These limits require, among other items, the development of a Mark 15 assembly subroutine for the CREDIT code.

  2. 46 CFR 160.026-5 - Marking.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... number shall be embossed on the top of the container. The container shall also be lithographed on one side in accordance with § 160.026-3(b) with the following: “U. S. Coast Guard Approval No. __” (Not...) (b) Other marking. In addition to any other marking placed on the smallest packing carton or box...

  3. 33 CFR 175.128 - Marking.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Marking. 175.128 Section 175.128 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) BOATING SAFETY EQUIPMENT REQUIREMENTS Visual Distress Signals § 175.128 Marking. No person may use a boat unless...

  4. 27 CFR 19.752 - Marks.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2012-04-01 2012-04-01 false Marks. 19.752 Section 19.752 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE... Marks. (a) Fuel alcohol. A proprietor of an alcohol fuel plant must place a conspicuous and...

  5. Fantasy and Reality in Mark Twain's Aggression.

    ERIC Educational Resources Information Center

    Sears, Robert R.

    Psychoanalysis, a favorite method for studying personality and motivation, cannot be used on the dead. Instead, biographical analysis must be employed. This study examines Mark Twain's aggression by analyzing his writings, social behavior, and environmental aspects of his life. In viewing Mark Twain's novels as representing fantasy, 17 categories…

  6. 7 CFR 956.162 - Container markings.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Container markings. 956.162 Section 956.162... WALLA VALLEY OF SOUTHEAST WASHINGTON AND NORTHEAST OREGON Rules and Regulations § 956.162 Container markings. Effective April 15, 1997, no handler shall ship any container of Walla Walla Sweet Onions...

  7. 46 CFR 161.012-15 - Markings.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 6 2013-10-01 2013-10-01 false Markings. 161.012-15 Section 161.012-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) EQUIPMENT, CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND APPROVAL ELECTRICAL EQUIPMENT Personal Flotation Device Lights § 161.012-15 Markings. (a)...

  8. 46 CFR 164.023-15 - Marking.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 6 2014-10-01 2014-10-01 false Marking. 164.023-15 Section 164.023-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) EQUIPMENT, CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND APPROVAL MATERIALS Thread for Personal Flotation Devices § 164.023-15 Marking. (a)...

  9. 46 CFR 169.545 - Markings.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Firefighting Equipment Personal Flotation Devices § 169.545 Markings. (a) Each personal flotation device must... persons onboard, the containers in which they are stowed must be marked “adult personal flotation devices” or “child personal flotation devices”, as appropriate, and with the number contained therein, in...

  10. 46 CFR 169.545 - Markings.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Firefighting Equipment Personal Flotation Devices § 169.545 Markings. (a) Each personal flotation device must... persons onboard, the containers in which they are stowed must be marked “adult personal flotation devices” or “child personal flotation devices”, as appropriate, and with the number contained therein, in...

  11. 46 CFR 169.545 - Markings.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Firefighting Equipment Personal Flotation Devices § 169.545 Markings. (a) Each personal flotation device must... persons onboard, the containers in which they are stowed must be marked “adult personal flotation devices” or “child personal flotation devices”, as appropriate, and with the number contained therein, in...

  12. 46 CFR 161.012-15 - Markings.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 6 2012-10-01 2012-10-01 false Markings. 161.012-15 Section 161.012-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) EQUIPMENT, CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND APPROVAL ELECTRICAL EQUIPMENT Personal Flotation Device Lights § 161.012-15 Markings. (a)...

  13. 46 CFR 164.023-15 - Marking.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 6 2013-10-01 2013-10-01 false Marking. 164.023-15 Section 164.023-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) EQUIPMENT, CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND APPROVAL MATERIALS Thread for Personal Flotation Devices § 164.023-15 Marking. (a)...

  14. 46 CFR 161.012-15 - Markings.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 6 2014-10-01 2014-10-01 false Markings. 161.012-15 Section 161.012-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) EQUIPMENT, CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND APPROVAL ELECTRICAL EQUIPMENT Personal Flotation Device Lights § 161.012-15 Markings. (a)...

  15. 46 CFR 161.012-15 - Markings.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 6 2011-10-01 2011-10-01 false Markings. 161.012-15 Section 161.012-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) EQUIPMENT, CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND APPROVAL ELECTRICAL EQUIPMENT Personal Flotation Device Lights § 161.012-15 Markings. (a)...

  16. 46 CFR 169.545 - Markings.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Firefighting Equipment Personal Flotation Devices § 169.545 Markings. (a) Each personal flotation device must... persons onboard, the containers in which they are stowed must be marked “adult personal flotation devices” or “child personal flotation devices”, as appropriate, and with the number contained therein, in...

  17. 46 CFR 160.036-5 - Marking.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Hand-Held Rocket-Propelled Parachute Red Flare Distress Signals § 160.036-5 Marking. (a) General. Each hand-held rocket-propelled parachute red flare distress signal shall be legibly marked or labeled as follows: (Company brand or style designation) Hand-Held...

  18. 46 CFR 160.036-5 - Marking.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Hand-Held Rocket-Propelled Parachute Red Flare Distress Signals § 160.036-5 Marking. (a) General. Each hand-held rocket-propelled parachute red flare distress signal shall be legibly marked or labeled as follows: (Company brand or style designation) Hand-Held...

  19. 46 CFR 160.036-5 - Marking.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Hand-Held Rocket-Propelled Parachute Red Flare Distress Signals § 160.036-5 Marking. (a) General. Each hand-held rocket-propelled parachute red flare distress signal shall be legibly marked or labeled as follows: (Company brand or style designation) Hand-Held...

  20. 46 CFR 160.036-5 - Marking.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Hand-Held Rocket-Propelled Parachute Red Flare Distress Signals § 160.036-5 Marking. (a) General. Each hand-held rocket-propelled parachute red flare distress signal shall be legibly marked or labeled as follows: (Company brand or style designation) Hand-Held...