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1

Physiological crosstalk between melatonin and glucocorticoid receptor modulates T-cell mediated immune responses in a wild tropical rodent, Funambulus pennanti.  

PubMed

Immunoenhancing attributes of melatonin (Mel) on the immunocompromised state induced by glucocorticoid is well known, but the involvement of their receptors in the modulation of immunity has never been studied in any rodent. The present study explores the role of Mel and its receptors (MT1 and MT2) in amelioration of immunocompromised state induced by a synthetic glucocorticoid, dexamethasone (Dex) in a tropical rodent Funambulus pennanti. Immune parameters viz. DTH response, Lymphocyte proliferation, cytokine (IL-2) and antibody production were assessed following pretreatment of Mel and Dex alone or in combination. Mel enhanced the IL-2 production, thymic and splenic lymphocyte proliferation thereby increasing T helper cell associated immune responses and anti-KLH-IgG production. MT1 and MT2 receptor expression was downregulated following Dex treatment while glucocorticoid receptors (GR) expression was downregulated in Mel treated groups suggesting that the immunomodulatory effects of glucocorticoids and Mel are mediated via their receptors. To gain further insights on the role of Mel receptors, we used nonselective melatonin receptor antagonist luzindole which resulted in reversal of most of the immunomodulatory actions of Mel. Therefore, it may be suggested that a physiological cross talk exist between Mel and GR which is of high adaptive significance in wild animals for balancing the immunity during ecologically stressful conditions. PMID:23059469

Gupta, Sameer; Haldar, Chandana

2013-03-01

2

The oxidative damages caused by ultraviolet radiation type C (UVC) to a tropical rodent Funambulus pennanti: role of melatonin.  

PubMed

Data suggests that UV radiation causes oxidative damage of the cells due to the release of inflammatory cytokines which in turn generates reactive oxygen species (ROS) that damages lipids, proteins and DNA. On the other hand, melatonin a potent antioxidant from the pineal gland under most of the conditions acts as a free radical scavenger. Our data suggests that melatonin pre-treatment (s.c. injections) significantly protected the diurnal squirrels from oxidative damages caused by UVC irradiation of 1528 mJ cm(-2) that induced suppression of delayed type hypersensitivity (DTH) responses. It also protected the rodents from UVC radiation induced increase in thiobarbituric acid reactive substances (TBARS) levels in spleen accompanied with a significant decrease in Superoxide Dismutase (SOD) activity indicating the occurrence of superoxide anion mediated damages following UVC exposure. Melatonin administration reduced the radiation induced oxidative stress in the spleen tissue as analyzed by reduced lipid damages and higher SOD activity. Under in vivo (100 ?g/100g body wt.) and in vitro (250 pg/10(6) cells) conditions, melatonin pre-treatment prevented spleen tissues and splenocytes from radiation induced cell death. In conclusion we may suggest that melatonin could be one of the potent antioxidant and radio protector that may reduce UV radiation induced toxicity to the cells and hence may be clinically important. PMID:23708058

Goswami, Soumik; Sharma, Shweta; Haldar, Chandana

2013-08-01

3

Melatonin ameliorates oxidative stress and induces cellular proliferation of lymphoid tissues of a tropical rodent, Funambulus pennanti, during reproductively active phase.  

PubMed

Effect of melatonin treatment on free radical production was assessed with simultaneous investigation of hormonal level (melatonin and testosterone), blastogenic response, stimulation index, and histological observation of lymphoid organs (spleen, thymus, and bone marrow) in male Indian palm squirrel (Funambulus pennanti) during reproductively active phase (RAP). Low endogenous melatonin and high testosterone level were noted during RAP. Daily subcutaneous injection of melatonin (25 ?g/100 g B wt.) at 17.30-18.00 h to squirrels for 60 consecutive days during May-June significantly decreased the thiobarbituric acid reactive substances (TBARS) level compared to control squirrels. Melatonin treatment significantly increased % stimulation ratio (%SR) of splenocytes and thymocytes against T cell mitogen concanavalin A. Pinealectomy (Px) led to a significant increase in TBARS level whereas a significant decrease was observed in blastogenic response and stimulation index was noted. Melatonin injection to Px squirrels showed restoration in %SR of thymocytes and splenocytes with a significant decrease in the TBARS level of the lymphoid tissues. Further, free radical load was induced by lipopolysaccharide (LPS; 400 ?g/ml) in lymphatic tissue homogenates and noted that melatonin supplementation (2 mM/ml) led to a significant decrease in TBARS level compared to the control and LPS-supplemented groups. Histological observation showed dense cellularity of thymocytes and splenocytes. Acridine orange staining technique shows a significant increase in thymocyte apoptosis Px squirrels when compared with melatonin-treated squirrels. These findings suggest that endogenous and exogenous melatonin might be responsible for the maintenance of immune system to adapt this seasonal breeder for the rigors of the environmental changes. PMID:22205185

Seema, Rai; Chandana, Haldar

2013-02-01

4

Effect of pinealectomy and testosterone on gonadal regression and accessory sex organs in Indian palm squirrel, Funambulus pennanti.  

PubMed

Indian palm squirrel (Funambulus pennanti), is a tropical seasonal breeder presents a short gonadal regression period (October-November), concomitant with declining plasma testosterone level. If pinealectomized (Px), however, squirrels maintain full gonadal activity and plasma testosterone levels. The aim of the present study was, therefore, to determine if the Px and exogenous testosterone in intact and Px squirrels would prevent natural gonadal regression. Experiment was performed during testicular regression phase (i.e. August end to November) revealed that both the Px (60 days) and exogenous testosterone (100 micrograms/day/squirrel/30 days) prevented gonadal and accessory sex organ regression. This could be due to negative feedback by testosterone treatment which was more obvious in intact than the Px squirrels. A decline in day time plasma melatonin level after testosterone treatment was also indicative of inverse relationship between the gonadal and pineal hormones which in turn did not allow the collapse of accessory sex organs. Further, the pineal gland is under direct control of steroid hormones since receptors and aromatizing enzymes are noted in the same. Therefore, a pineal secreted melatonin stimulation of hypothalamic negative feedback centers for gonadal regression could be suggested in this tropical rodent as receptors for melatonin have been detected in above areas. PMID:9357162

Haldar, C; Vidhu, S

1997-06-01

5

Problems associated with the control of rodents in tropical Africa  

PubMed Central

As elsewhere in the world, rodents are responsible for very considerable economic losses in tropical Africa because of their depredations on both growing crops and stored food products. Unfortunately, few accurate data are available on the extent of these losses but there is evidence that they are considerable. The public health importance of rodents, both as reservoirs and vectors of disease in tropical Africa, is also great; plague, leptospirosis, murine typhus, and Lassa fever are among the diseases associated with rodent hosts. Scientifically based rodent control programmes have been carried out in very few areas of Africa and there is urgent need for studies and demonstrations on rodent control in both urban and rural areas. The problems likely to be encountered are reviewed and methods of control proposed.

Gratz, N. G.; Arata, A. A.

1975-01-01

6

Ancient DNA and the tropics: a rodent's tale.  

PubMed

Most genetic studies of Holocene fauna have been performed with ancient samples from dry and cold regions, in which preservation of fossils is facilitated and molecular damage is reduced. Ancient DNA work from tropical regions has been precluded owing to factors that limit DNA preservation (e.g. temperature, hydrolytic damage). We analysed ancient DNA from rodent jawbones identified as Ototylomys phyllotis, found in Holocene and Late Pleistocene stratigraphic layers from Loltún, a humid tropical cave located in the Yucatan peninsula. We extracted DNA and amplified six short overlapping fragments of the cytochrome b gene, totalling 666 bp, which represents an unprecedented success considering tropical ancient DNA samples. We performed genetic, phylogenetic and divergence time analyses, combining sequences from ancient and modern O. phyllotis, in order to assess the ancestry of the Loltún samples. Results show that all ancient samples fall into a unique clade that diverged prior to the divergence of the modern O. phyllotis, supporting it as a distinct Pleistocene form of the Ototylomys genus. Hence, this rodent's tale suggests that the sister group to modern O. phyllotis arose during the Miocene-Pliocene, diversified during the Pleistocene and went extinct in the Holocene. PMID:24899682

Gutiérrez-García, Tania A; Vázquez-Domínguez, Ella; Arroyo-Cabrales, Joaquín; Kuch, Melanie; Enk, Jacob; King, Christine; Poinar, Hendrik N

2014-06-01

7

7. Rodenticides — Their Role in Rodent Pest Management in Tropical Agriculture  

Microsoft Academic Search

Rodents are serious pests of tropical agriculture. Most crops are attacked, particularly those grown for food by smallholders in the tropics. Globally, principal pest species include Sigmodon hispidus , Arvicanthis niloticus , Mastomys natalensis , Meriones spp., Bandicota spp., Rattus argentiventer and Microtus spp. Crop protection specialists usually recommend control programs based on integrated pest management (IPM) technologies involving the

Alan P. Buckle

8

Thermal energetics of the New-Guinean moss-forest rat (Rattus niobe) in comparison with other tropical murid rodents.  

PubMed

The thermal energetics of rodents from cool, wet tropical highlands are poorly known. Metabolic rate, body temperature and thermal conductance were measured in the moss-forest rat, Rattus niobe (Rodentia), a small murid endemic to the highlands of New Guinea. These data were evaluated in the context of the variation observed in the genus Rattus and among tropical murids. In 7 adult R. niobe, basal metabolic rate (BMR) averaged 53.6±6.6mLO2h(-1), or 103% of the value predicted for a body mass of 42.3±5.8g. Compared to other species of Rattus, R. niobe combines a low body temperature (35.5±0.6°C) and a moderately low minimal wet thermal conductance cmin (5.88±0.7mLO2h(-1)°C(-1), 95% of predicted) with a small size, all of which lead to reduced energy expenditure in a constantly cool environment. The correlations of mean annual rainfall and temperature, altitude and body mass with BMR, body temperature and cmin were analyzed comparatively among tropical Muridae. Neither BMR, nor cmin or body temperature correlated with ambient temperature or altitude. Some of the factors which promote high BMR in higher latitude habitats, such as seasonal exposure to very low temperature and short reproductive season, are lacking in wet montane tropical forests. BMR increased with rainfall, confirming a pattern observed among other assemblages of mammals. This correlation was due to the low BMR of several desert adapted murids, while R. niobe and other species from wet habitats had a moderate BMR. PMID:24679978

Genoud, Michel

2014-04-01

9

Effect of cadmium chloride on thyroid activity of the female Indian palm squirrel, Funambulus pennanti (Wroughton)  

SciTech Connect

In humans, exposure to Cadmium (Cd) occurs primarily through inhalation and ingestion. Acute Cd inhalation results in pulmonary edema and respiratory tract irritation; while chronic inhalation causes fibrotic and emphysematous changes in lung tissue as well as damage of renal proximal tubules. Several workers have reviewed the toxic effects of Cd on mammals, including man. In laboratory animals Cd produced kidney damage, testicular necrosis and atrophy, brain hemorrhage, hypertension, liver damage and reduced growth. It also induced changes in the adrenal and thyroid gland in the rat. In this study, squirrels, Funambulus pennanti, were administered a single dose of CdCl/sub 2/ intraperitoneally, and their thyroid structure and radioiodine I/sup 131/ uptake were assessed.

Shrivastava, V.K.; Sathyanesan, A.G.

1988-02-01

10

Elimination of testicular regression by 12-hr temporal relationship of serotonergic and dopaminergic activity in Indian palm squirrel, Funambulus pennanti.  

PubMed

Specific temporal relationship (12-hr) of serotonin and dopamine activity was induced by precursor drugs (5-HTP and L-DOPA) in Indian Palm Squirrel Funambulus pennanti during testicular regression phase. This treatment established breeding condition unlike control, which experienced complete atrophy of testes and accessory sex organs. It is obvious that seasonal testicular regression of Indian Palm Squirrel can be eliminated by 12 hr relation of 5-HTP and L-DOPA, which is not a pharmacological effect but actually is an alteration of seasonality in this annually breeding subtropical mammal. It may be concluded that specific phase relation (12-hr) between circadian serotonergic and dopaminergic oscillations may induce breeding condition in regressing gonad of Indian Palm Squirrel during post-reproductive phase of annual gonadal cycle. It is also suggested that inspite of the different environmental factors (photoperiod, humidity etc.) used by different species to time their annual reproduction, basic regulatory mechanism of seasonality appears to be the same, i.e., temporal synergism of neurotransmitter activity. PMID:2054149

Jaiwal, R; Chaturvedi, C M

1991-01-01

11

Modulation of immunity in young-adult and aged squirrel, Funambulus pennanti by melatonin and p-chlorophenylalanine  

PubMed Central

Background Our interest was to find out whether pineal gland and their by melatonin act as modulator of immunosenescence. Parachlorophenylalanine (PCPA) – a ? adrenergic blocker, is known to perform chemical pinealectomy (Px) by suppressing indirectly the substrate 5-hydroxytryptamine (5-HT) for melatonin synthesis and thereby melatonin itself. The role of PCPA, alone and in combination with melatonin was recorded in immunomodulation and free radical load in spleen of young adult and aged seasonal breeder Indian palm squirrel Funambulus pennanti. Results Aged squirrel presented reduced immune parameters (i.e. total leukocyte count (TLC), Lymphocytes Count (LC), % stimulation ratio of splenocytes (% SR) against T cell mitogen concanavalin A (Con A), delayed type hypersensitivity (DTH) to oxazolone) when compared to young adult group. Melatonin administration (25 ?g/100 g body mass/day) significantly increased the immune parameters in aged more than the young adult squirrel while PCPA administration (4.5 mg/100 g body mass/day) reduced all the immune parameters more significantly in young than aged. Combination of PCPA and melatonin significantly increased the immune parameters to the normal control level of both the age groups. TBARS level was significantly high in aged than the young group. PCPA treatment increased TBARS level of young and aged squirrels both while melatonin treatment decreased it even than the controls. Nighttime peripheral melatonin level was low in control aged group than the young group. Melatonin injection at evening hours significantly increased the peripheral level of nighttime melatonin, while combined injection of PCPA and melatonin brought it to control level in both aged and young adult squirrels. Conclusion PCPA suppressed immune status more in aged than in adult by reducing melatonin level as it did chemical Px. Melatonin level decreased in control aged squirrels and so there was a decrease in immune parameters with a concomitant increase in free radical load of spleen. Decreased immune status can be restored following melatonin injection which decreased free radical load of spleen and suggest that immune organs of aged squirrels were sensitive to melatonin. Increased free radical load and decreased peripheral melatonin could be one of the reasons of immunosenescence.

Rai, Seema; Haldar, Chandana; Singh, Rajesh

2009-01-01

12

Rodent repellency  

USGS Publications Warehouse

In the course of studies involving more than 2,500 chemical repellents, it has been found that certain groups of- compounds containing nitrogen or sulfur are repellent to rats under the , test conditions and it appears probable that some of these compounds might be used for the protection of packaged goods against rodent attacks. Additional tests to determine optimum methods of application will be necessary before final evaluation of these compounds will be possible and extensive field trials will be required to establish the degree of protection which may be afforded by the use of these materials. Pending such final evaluation, it may be assumed that the results,to date offer a means of selecting the most promising types of'materials for further trial....On the basis of the test data, it appears that some amine derivative, such as a salt of some organic, acid, or a complex with trinitrobenzene or with a metallic salt of a dialkyl dithiocarbamic acid might offer promise of protection of packaging materials against rodent attacks....Protection might be obtained through the use of certain 'physical deterrents' such as plastics, waxes or drying oils.

DeWitt, J.B.; Welch, J.F.; Bellack, E.

1950-01-01

13

Tropical dermatology: Bacterial tropical diseases  

Microsoft Academic Search

Bacterial infections are common in tropical parts of the world and can include those species also seen regularly in temperate climates. Many tropical bacterial infections, however, are rarely diagnosed in temperate parts of the world and include bartonellosis, tropical ulcer, tropical pyomyositis, granuloma inguinale, lymphogranuloma venereum, yaws, pinta, melioidosis, and glanders. Some tropical bacterial diseases, eg, plague and anthrax, are

Omar Lupi; Vandana Madkan; Stephen K. Tyring

2006-01-01

14

Fungal diseases of laboratory rodents.  

PubMed

Although fungal disease is uncommon in rodents, dermatophytosis is the most common mycosis seen in clinical practice. T. mentagrophytes is the most common etiologic agent, and the guinea pig is the most common species affected, although there are reports in all pet and laboratory rodent species except the gerbil. Despite the low incidence of clinical disease, rodents are common asymptomatic carriers of dermatophytes, and ringworm is the most common zoonotic disease transmitted from rodents to people. PMID:12827729

Pollock, Christal

2003-05-01

15

Microevolution in island rodents  

Microsoft Academic Search

We perform a meta-analysis on morphological data from four island rodent populations exhibiting microevolution (>˜?100 years). Data consisting of incidences of skeletal variants, cranial, and external measurements are from house mice (Mus musculus) on one Welsh and one Scottish island, black rats (Rattus rattus) on two Galapagos islands, and deer mice (Peromyscus maniculatus) on three California Channel islands. We report

Oliver R. W. Pergams; Mary V. Ashley

2001-01-01

16

Estrogenic isoflavones in rodent diets  

Microsoft Academic Search

Many rodent diets contain components such as soy isoflavones (daidzein and genistein) known to have estrogenic properties. The dietary background of phytoestrogens may modulate some responses to environmental estrogens when these compounds are tested in rodent bioassays. Thus, and since only few data were available on the phytoestrogen content of rodent diets commonly used in European laboratories, it was of

Gisela H. Degen; Petra Janning; Patrick Diel; Hermann M. Bolt

2002-01-01

17

Microevolution in island rodents  

Microsoft Academic Search

\\u000a We perform a meta-analysis on morphological data from four island rodent populations exhibiting microevolution (

Oliver R. W. Pergams; Mary V. Ashley

18

Microdialysis in Rodents  

PubMed Central

Microdialysis is an in vivo sampling technique that permits the quantification of various substances (e.g., neurotransmitters, peptides, electrolytes) in blood and tissue. It is also used to infuse substances into the brain and spinal cord. This unit describes methods for the construction and stereotaxic implantation of microdialysis probes into discrete brain regions of the rat and mouse. Procedures for the conduct of conventional and quantitative microdialysis experiments in the awake and anesthetized rodent are also provided.

Zapata, Agustin; Chefer, Vladimir I.; Shippenberg, Toni S.

2010-01-01

19

Toxoplasmosis seroprevalence in urban rodents: a survey in Niamey, Niger  

PubMed Central

A serological survey of Toxoplasma gondii was conducted on 766 domestic and peridomestic rodents from 46 trapping sites throughout the city of Niamey, Niger. A low seroprevalence was found over the whole town with only 1.96% of the rodents found seropositive. However, differences between species were important, ranging from less than 2% in truly commensal Mastomys natalensis, Rattus rattus and Mus musculus, while garden-associated Arvicanthis niloticus displayed 9.1% of seropositive individuals. This is in line with previous studies on tropical rodents - that we reviewed here - which altogether show that Toxoplasma seroprevalence in rodent is highly variable, depending on many factors such as locality and/or species. Moreover, although we were not able to decipher statistically between habitat or species effect, such a contrast between Nile grass rats and the other rodent species points towards a potentially important role of environmental toxoplasmic infection. This would deserve to be further scrutinised since intra-city irrigated cultures are extending in Niamey, thus potentially increasing Toxoplasma circulation in this yet semi-arid region. As far as we are aware of, our study is one of the rare surveys of its kind performed in Sub-Saharan Africa and the first one ever conducted in the Sahel.

Mercier, Aurelien; Garba, Madougou; Bonnabau, Henri; Kane, Mamadou; Rossi, Jean-Pierre; Darde, Marie-Laure; Dobigny, Gauthier

2013-01-01

20

Thieving rodents as substitute dispersers of megafaunal seeds  

PubMed Central

The Neotropics have many plant species that seem to be adapted for seed dispersal by megafauna that went extinct in the late Pleistocene. Given the crucial importance of seed dispersal for plant persistence, it remains a mystery how these plants have survived more than 10,000 y without their mutualist dispersers. Here we present support for the hypothesis that secondary seed dispersal by scatter-hoarding rodents has facilitated the persistence of these large-seeded species. We used miniature radio transmitters to track the dispersal of reputedly megafaunal seeds by Central American agoutis, which scatter-hoard seeds in shallow caches in the soil throughout the forest. We found that seeds were initially cached at mostly short distances and then quickly dug up again. However, rather than eating the recovered seeds, agoutis continued to move and recache the seeds, up to 36 times. Agoutis dispersed an estimated 35% of seeds for >100 m. An estimated 14% of the cached seeds survived to the next year, when a new fruit crop became available to the rodents. Serial video-monitoring of cached seeds revealed that the stepwise dispersal was caused by agoutis repeatedly stealing and recaching each other’s buried seeds. Although previous studies suggest that rodents are poor dispersers, we demonstrate that communities of rodents can in fact provide highly effective long-distance seed dispersal. Our findings suggest that thieving scatter-hoarding rodents could substitute for extinct megafaunal seed dispersers of tropical large-seeded trees.

Jansen, Patrick A.; Hirsch, Ben T.; Emsens, Willem-Jan; Zamora-Gutierrez, Veronica; Wikelski, Martin; Kays, Roland

2012-01-01

21

Thieving rodents as substitute dispersers of megafaunal seeds.  

PubMed

The Neotropics have many plant species that seem to be adapted for seed dispersal by megafauna that went extinct in the late Pleistocene. Given the crucial importance of seed dispersal for plant persistence, it remains a mystery how these plants have survived more than 10,000 y without their mutualist dispersers. Here we present support for the hypothesis that secondary seed dispersal by scatter-hoarding rodents has facilitated the persistence of these large-seeded species. We used miniature radio transmitters to track the dispersal of reputedly megafaunal seeds by Central American agoutis, which scatter-hoard seeds in shallow caches in the soil throughout the forest. We found that seeds were initially cached at mostly short distances and then quickly dug up again. However, rather than eating the recovered seeds, agoutis continued to move and recache the seeds, up to 36 times. Agoutis dispersed an estimated 35% of seeds for >100 m. An estimated 14% of the cached seeds survived to the next year, when a new fruit crop became available to the rodents. Serial video-monitoring of cached seeds revealed that the stepwise dispersal was caused by agoutis repeatedly stealing and recaching each other's buried seeds. Although previous studies suggest that rodents are poor dispersers, we demonstrate that communities of rodents can in fact provide highly effective long-distance seed dispersal. Our findings suggest that thieving scatter-hoarding rodents could substitute for extinct megafaunal seed dispersers of tropical large-seeded trees. PMID:22802644

Jansen, Patrick A; Hirsch, Ben T; Emsens, Willem-Jan; Zamora-Gutierrez, Veronica; Wikelski, Martin; Kays, Roland

2012-07-31

22

Geomagnetic field detection in rodents  

SciTech Connect

In addition to behavioral evidence for the detection of earth-strength magnetic fields (MF) by rodents, recent investigations have revealed that electrophysiological and biochemical responses to MF occur in the pineal organ and retina of rodents. In addition, ferrimagnetic deposits have been identified in the ethmoidal regions of the rodent skull. These findings point to a new sensory phenomenon, which interfaces with many fields of biology, including neuroscience, psychophysics, behavioral ecology, chronobiology and sensory physiology.

Olcese, J.; Reuss, S.; Semm, P.

1988-01-01

23

Tropical malabsorption  

PubMed Central

Malabsorption is an important clinical problem both in visitors to the tropics and in native residents of tropical countries. Infections of the small intestine are the most important cause of tropical malabsorption. Protozoal infections cause malabsorption in immunocompetent hosts, but do so more commonly in the setting of immune deficiency. Helminth infections occasionally cause malabsorption or protein?losing enteropathy. Intestinal tuberculosis, chronic pancreatitis and small?bowel bacterial overgrowth are important causes of tropical malabsorption. In recent years, inflammatory bowel disease and coeliac disease have become major causes of malabsorption in the tropics. Sporadic tropical sprue is still an important cause of malabsorption in adults and in children in South Asia. Investigations to exclude specific infective, immunological or inflammatory causes are important before considering tropical sprue as a diagnosis. This article briefly reviews the management of tropical sprue and presents an algorithm for its investigation and management.

Ramakrishna, B S; Venkataraman, S; Mukhopadhya, A

2006-01-01

24

Tropical Convexity  

Microsoft Academic Search

The notions of convexity and convex polytopes are introduced in the setting of tropical geometry. Combinatorial types of tropical polytopes are shown to be in bijection with regular triangulations of products of two simplices. Applications to phylogenetic trees are discussed. Theorem 29 and Corollary 30 in the paper, relating tropical polytopes to injective hulls, are incorrect. See the erratum at

Mike Develin; Bernd Sturmfels

2003-01-01

25

Besnoitiosis in Rodents from Colorado.  

National Technical Information Service (NTIS)

Parasitic cysts of Besnoitia jellisoni (coccidia) were found in rodents (Peromyscus maniculatus and Spermophilus tridecemlineatus) trapped in Eastern Colorado. The parasite was associated with a granulomatous inflammatory reaction in the lungs of each rod...

G. E. Dagle R. R. Adee T. F. Winsor

1977-01-01

26

Invasive rodent eradication on islands.  

PubMed

Invasive mammals are the greatest threat to island biodiversity and invasive rodents are likely responsible for the greatest number of extinctions and ecosystem changes. Techniques for eradicating rodents from islands were developed over 2 decades ago. Since that time there has been a significant development and application of this conservation tool. We reviewed the literature on invasive rodent eradications to assess its current state and identify actions to make it more effective. Worldwide, 332 successful rodent eradications have been undertaken; we identified 35 failed eradications and 20 campaigns of unknown result. Invasive rodents have been eradicated from 284 islands (47,628 ha). With the exception of two small islands, rodenticides were used in all eradication campaigns. Brodifacoum was used in 71% of campaigns and 91% of the total area treated. The most frequent rodenticide distribution methods (from most to least) are bait stations, hand broadcasting, and aerial broadcasting. Nevertheless, campaigns using aerial broadcast made up 76% of the total area treated. Mortality of native vertebrates due to nontarget poisoning has been documented, but affected species quickly recover to pre-eradication population levels or higher. A variety of methods have been developed to mitigate nontarget impacts, and applied research can further aid in minimizing impacts. Land managers should routinely remove invasive rodents from islands <100 ha that lack vertebrates susceptible to nontarget poisoning. For larger islands and those that require nontarget mitigation, expert consultation and greater planning effort are needed. With the exception of house mice (Mus musculus), island size may no longer be the limiting factor for rodent eradications; rather, social acceptance and funding may be the main challenges. To be successful, large-scale rodent campaigns should be integrated with programs to improve the livelihoods of residents, island biosecurity, and reinvasion response programs. PMID:17883491

Howald, Gregg; Donlan, C Josh; Galván, Juan Pablo; Russell, James C; Parkes, John; Samaniego, Araceli; Wang, Yiwei; Veitch, Dick; Genovesi, Piero; Pascal, Michel; Saunders, Alan; Tershy, Bernie

2007-10-01

27

Tropical dermatology: Fungal tropical diseases  

Microsoft Academic Search

Fungal infections are common in tropical countries and can have an important impact on public health. Lobomycosis is a common fungal infection in the tropical rain forest of South America, and paracoccidioidomycosis (South American blastomycosis) is a widespread and sometimes severe illness. Penicilliosis marneffeiis an opportunistic infection of AIDS patients in southeast Asia. Chromoblastomycosis and mycetomas are causes of morbidity

Omar Lupi; Stephen K. Tyring; Michael R. McGinnis

28

Digestive responses of two omnivorous rodents (Peromyscus maniculatus and P. alstoni) feeding on epigeous fungus (Russula occidentalis).  

PubMed

The sporocarps of hypogeous and epigeous fungi are important dietary items for forest dwelling rodents in temperate and tropical forests throughout the world. However, results of some pioneering works have demonstrated that fungi cannot be considered as nutritionally high-quality food items for some mycophagous small rodents. According to these studies, when mycophagous rodents feed on fungus, they showed a minimal digestibility, but whether this applies to most rodent species that include fungi in their diets is unknown. In this study, we experimentally evaluated body mass changes and feed preferences in captive deer (Peromyscus maniculatus) and volcano (P. alstoni) mice when fed on epigeous fungus (Russula occidentalis). In experiment 1, the animals were fed with fungus as the only feedstuff in comparison to regular rodent chow and oat. In experiment 2, the animals were fed with fungus in a free-choice arrangement together with equal amounts of rodent chow and oat. Both species lost approximately 15% of their body mass within 4 days when fed on fungus alone, but gained 5-10% body mass during the same time period when ingesting oat and rodent chow, respectively, as the only feedstuff. However, in contrast, in the free-choice arrangement with all three feedstuffs, both species gained 20-30% body mass, and showed the highest feed preference for fungus followed by oat and rodent chow. In addition, apparent digestibility of energy and nitrogen were analyzed in both rodent species, which were 50-60% for fungus, whereas approximately 90-94% for rodent chow and oat. According to our results, animals need to supplement their diets with alternative high-quality food items in order to maintain and increase their body mass, suggesting that epigeous fungi are only of moderate nutritional value for small rodents. Futures studies should focus on exploring the importance of a mixture of fungal species in the diet of small mycophagous rodents. PMID:17653726

D'Alva, T; Lara, C; Estrada-Torres, A; Castillo-Guevara, C

2007-10-01

29

Probing perceptual decisions in rodents  

PubMed Central

The study of perceptual decision-making offers insight into how the brain uses complex, sometimes ambiguous information to guide actions. Understanding the underlying processes and their neural bases requires that one pair recordings and manipulations of neural activity with rigorous psychophysics. Though this research has been traditionally performed in primates, it seems increasingly promising to pursue it at least partly in mice and rats. However, rigorous psychophysical methods are not yet as developed for these rodents as they are for primates. Here we give a brief overview of the sensory capabilities of rodents and of their cortical areas devoted to sensation and decision. We then review methods of psychophysics, focusing on the technical issues that arise in their implementation in rodents. These methods represent a rich set of challenges and opportunities.

Carandini, Matteo; Churchland, Anne K

2014-01-01

30

Tropical Margins  

Microsoft Academic Search

\\u000a On our planet, the ocean margins between the Tropic of Capricorn (23°27?S) and the Tropic of Cancer (23°27?N) are directly\\u000a below the sun and are consequently warmer than other parts of the earth. Higher solar energy inputs are about the only rational\\u000a (but still contested) explanation for the orders of magnitude greater biological species diversity (Allen et al. 2002; Algar

G. J. Brunskill

31

Oral disorders of exotic rodents.  

PubMed

Our dental knowledge of rodents is still patchy but their increasing popularity and advances in technology allow us to make good strides toward better understanding. Cutting incisors with nail clippers and treating incisor problems without examining cheek teeth is no longer acceptable. Good practice dictates that a thorough examination is performed, a diagnosis is made, and treatment is planned and executed appropriately. Dentistry is expanding at a tremendous rate; the next few years should provide plenty of opportunities to solve most of the remaining problems with dental disease in rodents. PMID:14534975

Legendre, Loïc F

2003-09-01

32

Variable effects of host characteristics on species richness of flea infracommunities in rodents from three continents.  

PubMed

We studied the effect of host gender and body mass on species richness of flea infracommunities in nine rodent host species from three biomes (temperate zone of central Europe, desert of the Middle East and the tropics of East Africa). Using season- and species-specific generalized linear mixed models and controlling for year-to-year variation, spatial clustering of rodent sampling and over-dispersion of the data, we found inconsistent associations between host characteristics and flea species richness. We found strong support for male-biased flea parasitism, especially during the reproductive period (higher species richness in male hosts than in females) in all considered European rodents (Apodemus agrarius, Myodes glareolus and Microtus arvalis) and in one rodent species from the Middle East (Dipodillus dasyurus). In contrast, two of three African rodent species (Lophuromys kilonzoi and Praomys delectorum) demonstrated a trend of female-biased flea species richness. Positive associations between body mass and the number of flea species were detected mainly in males (five of nine species: A. agrarius, M. glareolus, M. arvalis, D. dasyurus and Mastomys natalensis) and not in females (except for M. natalensis). The results of this study support earlier reports that gender-biased, in general, and male-biased, in particular, infestation by ectoparasites is not a universal rule. This suggests that mechanisms of parasite acquisition by an individual host are species-specific and have evolved independently in different rodent host-flea systems. PMID:24820040

Kiffner, Christian; Stanko, Michal; Morand, Serge; Khokhlova, Irina S; Shenbrot, Georgy I; Laudisoit, Anne; Leirs, Herwig; Hawlena, Hadas; Krasnov, Boris R

2014-08-01

33

Identifying Rodent Hantavirus Reservoirs, Brazil  

PubMed Central

We describe the genetic analysis of samples from hantavirus pulmonary syndrome (HPS) patients from southern and southeastern states of Brazil and rodents captured at the presumed site of infection of these patients. A total of 65 samples that were antibody-positive for Sin Nombre or Laguna Negra virus by enzyme-linked immunosorbent assay were processed by nested reverse transcription–polymerase chain reaction (RT-PCR) by using several primer combinations in the M and S genome segments. PCR products were amplified and sequenced from samples from 11 HPS patient and 7 rodent samples. Phylogenetic analysis of nucleotide sequence differences showed the cocirculation of Araraquara and Juquitiba-like viruses, previously characterized from humans. Our genetic data indicate that Araraquara virus is associated with Bolomys lasiurus (hairy-tailed Bolo mouse) and the Juquitiba-like virus is associated with Oligoryzomys nigripes (black-footed pigmy rice rat).

Bisordi, Ivani; Levis, Silvana; Garcia, Jorge; Pereira, Luiz E.; Souza, Renato P.; Sugahara, Teresa K.N.; Pini, Noemi; Enria, Delia; Souza, Luiza T.M.

2004-01-01

34

SEXUAL BEHAVIOR IN MALE RODENTS  

PubMed Central

The hormonal factors and neural circuitry that control copulation are similar across rodent species, although there are differences in specific behavior patterns. Both estradiol (E) and dihydrotestosterone (DHT) contribute to the activation of mating, although E is more important for copulation and DHT, for genital reflexes. Hormonal activation of the medial preoptic area (MPOA) is most effective, although implants in the medial amygdala (MeA) can also stimulate mounting in castrates. Chemosensory inputs from the main and accessory olfactory systems are the most important stimuli for mating in rodents, especially in hamsters, although genitosensory input also contributes. Dopamine agonists facilitate sexual behavior, and serotonin (5-HT) is generally inhibitory, though certain 5-HT receptor subtypes facilitate erection or ejaculation. Norepinephrine agonists and opiates have dose-dependent effects, with low doses facilitating and high doses inhibiting behavior.

Hull, Elaine M.; Dominguez, Juan M.

2007-01-01

35

[Intraocular pressure measurement in rodents].  

PubMed

The ability to measure intraocular pressure in rodents is very important for the advancement of glaucoma research. This review article describes various currently used methods, such as, microcannulation, servo-null micropipette, Tonopen tonometer, rebound tonometer, Goldmann applanation tonometer, Schiötz indentation tonometer, pneumatonometer, and optic interferometry tonometer. Their principles of operation, advantages and limitations, as well as a calibration method are also discussed. PMID:18953904

Pang, Iok-hou; Wang, Wan-heng; Millar, J Cameron; Clark, Abbot F

2008-05-01

36

Prospects for biological control of rodent populations*  

PubMed Central

Pathogens and predatory animals are the main agents used for the biological control of rodents. The pathogens that have been used are of the genus Salmonella; none is rodent-specific and all can cause severe infection in man and domestic animals. Furthermore, rodents frequently develop immunity to, and become carriers of, these organisms, and there is little to commend their use, except in lightly populated areas where control is infrequently applied. The relationships of five predator species with their rodent prey have been examined. The monitor lizard, mongoose, and ferret were for different reasons found to be unsatisfactory, and there is not yet sufficient evidence to warrant further releases of the Japanese weasel. Domestic and feral cats control rodents well in some situations but only after some other agent has removed a large part of the rodent population.

Wodzicki, Kazimierz

1973-01-01

37

Transfection of rodent malaria parasites.  

PubMed

Gene manipulation is an invaluable tool to investigate and understand the biology of an organism. Although this technology has been applied to both the human and rodent malarial parasites (RMP), Plasmodium berghei in particular offers a more robust system due to a higher and more efficient transformation rate. Here, we describe a comprehensive transfection and selection protocol using P. berghei including a variant negative selection protocol administering 5-fluorocytosine to the animals in drinking water. Additionally, we discuss and assess the latest advances in gene manipulation technologies developed in RMP to gain a better understanding of Plasmodium biology. PMID:22990773

Philip, Nisha; Orr, Rachael; Waters, Andrew P

2013-01-01

38

The Miocene rodents of Serbia  

NASA Astrophysics Data System (ADS)

During the Miocene period a group of shallow lakes was created in depressions at the territory of present-day Serbia. This caused the present wide distribution of lacustrine sediments, which occasionally alternate with the alluvial and marsh sediments. The remains of large mammals are relatively common, while the remains of small mammals used to be known only from two localities - Mala Miliva and Sibnica. The method of sediment sieving, used during the last decade, led to discovery of 6 new localities with remains of fossil vertebrates - Sibnica 1, Vra?evi?i, village Lazarevac, Bele Vode, Brajkovac and Tavnik. Most of the fossil material is represented by osteological and odontological remains of small mammals. The best represented group of small mammals at each of the localities was the rodents. According to the odontological material presence was proven for 35 rodent species from 6 families. MN zonation was determined according to structure of associations. The geological age of fossil-bearing sediments was determined by using the method of correlation with the sites in Europe and Turkey.

Markovic, Z.

2009-04-01

39

20 CFR 654.415 - Insect and rodent control.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Insect and rodent control. 654.415 Section...Workers Housing Standards § 654.415 Insect and rodent control. Housing and facilities shall be free of insects, rodents, and other...

2013-04-01

40

Insecticide-Treated Rodent Baits for Sand Fly Control.  

National Technical Information Service (NTIS)

Rodent baits containing systemic insecticides are potential tools to interrupt the cycle of transmission of Leishmania parasites by killing sand flies that take bloodmeals from rodents as adults. Bio-indicators that can be used in conjunction with rodent-...

J. D. Bast J. W. Clark R. W. Stout S. W. Gordon T. M. Mascari

2013-01-01

41

Tropical Convection's Roles in Tropical Tropopause Cirrus.  

National Technical Information Service (NTIS)

The results presented here show that tropical convection plays a role in each of the three primary processes involved in the in situ formation of tropopause cirrus. First, tropical convection transports moisture from the surface into the upper troposphere...

M. T. Boehm D. O. C. Starr J. Verlinde S. Lee

2002-01-01

42

Leptospirosis in Man and Rodents on Taiwan.  

National Technical Information Service (NTIS)

A survey for leptospirosis in man and wild rodents in Taiwan, by serologic and cultural techniques, is presented. Of 586 rodents studied, (6.48%) were positive by the macroscopic slide-agglutination test, and 20 were positive by culture. (Author)

J. W. Fresh C. C. Tsai C. H. Lai C. T. Chang

1968-01-01

43

A Guide to Research Rodent Housing  

Microsoft Academic Search

BACKGROUND Laboratory rodents have been used in the United States as research animals since the late 1800s. In the past, housing of rodents used for research was designed primarily to prevent escape, to provide easy access to the animals by researchers, to allow the animals ready access to food and water, and to allow efficient dirty bedding removal and cage

William J. White

44

Regional specification of rodent and human neurospheres  

Microsoft Academic Search

Neural precursor cells were isolated from various regions of the developing rat and human brain and grown in culture as aggregates termed neurospheres. We asked whether cells within human and rodent neurospheres are identical, or whether they have species specific characteristics or differences based on their region of origin. Under our culture conditions, rodent neurospheres isolated from the cortex (ctxNS)

T Ostenfeld; Etienne Joly; Yu-Tzu Tai; Anna Peters; Maeve Caldwell; Eric Jauniaux; C. N Svendsen

2002-01-01

45

Rodent-Vegetation Relationships in Southeastern Montana  

Microsoft Academic Search

Plant communities of southeastern Montana were surveyed for rodents over a two year period. Deer mice (Peromyscus maniculatus) were the most abundant rodent species found on the study area. Prairie voles (Microtus ochrogaster), meadow voles (M. pennsylvanicus), sagebrush voles (Lagurus curtatus), Wyoming pocket mice (Perognathus fasciatus), thirteen-lined ground squirrels (Spermophilus tridecemlineatus), least chipmunks (Eutamias minimus), and eastern fox squirrels (Sciurus

Daniel W. Uresk; Richard M. Hansen

46

Seed choice by rodents: learning or inheritance?  

Microsoft Academic Search

Learning plays a central role in animal life, and it has received special attention in the context of foraging. In this study,\\u000a we have tested whether learning operates in seed choices by rodents using the Algerian mouse (Mus spretus) and Holm oak (Quercus ilex) acorns as a model. At the laboratory, those rodents captured in the field during the acorn

Alberto Muñoz; Raúl Bonal

2008-01-01

47

Oldest fossil record of gliding in rodents  

Microsoft Academic Search

EOMYIDAE is an extinct family of rodents with a wide distribution in North America, Europe and Asia1-3. Of the modern rodent groups, eomyids are most closely related to New World pocket mice (heteromyids) and pocket gophers (geomyids)4. Eomyids occurred from the late Eocene through the Pliocene, spanning a time period of about 40 million years. From Europe alone, 11 genera

G. Storch; B. Engesser; M. Wuttke

1996-01-01

48

Rodent Models for Metabolic Syndrome Research  

PubMed Central

Rodents are widely used to mimic human diseases to improve understanding of the causes and progression of disease symptoms and to test potential therapeutic interventions. Chronic diseases such as obesity, diabetes and hypertension, together known as the metabolic syndrome, are causing increasing morbidity and mortality. To control these diseases, research in rodent models that closely mimic the changes in humans is essential. This review will examine the adequacy of the many rodent models of metabolic syndrome to mimic the causes and progression of the disease in humans. The primary criterion will be whether a rodent model initiates all of the signs, especially obesity, diabetes, hypertension and dysfunction of the heart, blood vessels, liver and kidney, primarily by diet since these are the diet-induced signs in humans with metabolic syndrome. We conclude that the model that comes closest to fulfilling this criterion is the high carbohydrate, high fat-fed male rodent.

Panchal, Sunil K.; Brown, Lindsay

2011-01-01

49

[Tropical mycoses].  

PubMed

The most common tropical subcutaneous and deep mycoses include chromomycosis, sporotrichosis and mycetoma. All are commonly found in Natal and in other sub-tropical countries. Although blastomycosis is endemic in North America, only four cases have been identified in Natal during the last 25 years and all presented with atypical clinical features. African histoplasmosis caused by H. capsulatum var. duboisii and limited mainly to central and western Africa has been found in only one patient in Natal. Paracoccidioidomycosis, although the most common deep mycosis in Latin America, is limited to that area and we have no experience of this disease in South Africa. Over the past eight years itraconazole has been used in clinical trials for all these mycoses. The results in sporotrichosis, non-meningeal blastomycosis and paracoccidioidomycosis suggest that for these diseases itraconazole may be the drug of choice. The results in histoplasmosis are encouraging as are the results in chromomycosis particularly those cases associated with C. carrionii. However, where F. pedrosoi is the causal agent and in mycetomas, successful management still remains a therapeutic problem. In our own experience and that of other using itraconazole, even over prolonged periods, this drug has an impressive safety profile. In our present series of 42 patients, no side effects were observed, no adverse reactions occurred and serum chemistry values remained within normal limits. It appears, therefore, that itraconazole, although not the final answer to management of the deep mycoses, is certainly a major improvement on previous drugs. PMID:1663201

Bayles, M A

1991-12-01

50

Guinea-zilla? World's largest rodent  

NSDL National Science Digital Library

Roughly the size of a buffalo, a giant rodent that roamed the banks of an ancient Venezuelan river some 8 million years ago, dining on sea grass and dodging crocodiles, was an evolutionary sibling to modern-day guinea pigs.

American Association for the Advancement of Science (AAAS;)

2008-07-03

51

Rodent-borne diseases in Thailand: targeting rodent carriers and risky habitats  

PubMed Central

Background Comparative analysis, which aims at investigating ecological and evolutionary patterns among species, may help at targeting reservoirs of zoonotic diseases particularly in countries presenting high biodiversity. Here, we developed a simple method to target rodent reservoirs using published studies screening microparasite infections. Methods We compiled surveys of microparasites investigated in rodents trapped in Thailand. The data comprise a total of 17,358 rodents from 18 species that have been investigated for a total of 10 microparasites (viruses, bacteria and protozoans). We used residual variation of microparasite richness controlled for both rodent sample size and pathogens’ screening effort to identify major rodent reservoirs and potential risky habitats. Results Microparasite species richness was positively related to rodent sample size and pathogens’ screening effort. The investigation of the residual variations of microparasite species richness showed that several rodent species harboured more pathogens than expected by the regression model. Similarly, higher pathogen richness than expected was observed in rodents living in non-flooded lands, forests and paddy fields. Conclusion Our results suggest to target some rodent species that are not commonly investigated for pathogen screening or surveillance such as R. adamanensis or B. savilei, and that non-flooded lands and forests should be more taken into caution, whereas much surveys focused on paddy rice fields and households.

Herbreteau, Vincent; Bordes, Frederic; Jittapalapong, Sathaporn; Supputamongkol, Yupin; Morand, Serge

2012-01-01

52

Role of the Veterinary Pathologist on the Tropical Medicine Research Team; Observations in Indonesia.  

National Technical Information Service (NTIS)

In areas where public health and sanitary conditions are such that man comes in frequent daily contact with animals in his environment, rodent-borne human diseases are an important health hazard. Because of the year-round warm, humid climate in the tropic...

R. J. Brown P. L. Joseph

1978-01-01

53

Tropical mycoses.  

PubMed

The most common tropical subcutaneous and deep mycoses include chromomycosis, sporotrichosis and mycetoma. All are commonly found in Natal and in other subtropical countries. Although blastomycosis is endemic in North America, only 4 cases have been identified in Natal during the last 25 years, and all presented with atypical clinical features. African histoplasmosis, caused by Histoplasma capsulatum var. duboisii and limited mainly to central and western Africa, has been found in only 1 patient in Natal. Paracoccidioidomycosis, though the most common deep mycosis in Latin America, is limited to that area and there is no experience of this disease in South Africa. Over the past 8 years, itraconazole has been used in clinical trials for all 3 mycoses. The results in sporotrichosis, non-meningeal blastomycosis and paracoccidioidomycosis suggest that for these diseases itraconazole may be the drug of choice. The results in histoplasmosis are encouraging, as are the results in chromomycosis, particularly those cases associated with Cladosporium carrionii. Where Fonsecaea pedrosoi is the causal agent and in mycetomas, however, successful management still remains a therapeutic problem. Enhanced efficacy by combining flucytosine and itraconazole was seen in 3 patients. Even over prolonged periods, itraconazole has an impressive safety profile. In the present series of 41 patients, no side-effects were observed, no adverse reactions occurred, and serum chemistry values remained within normal limits. It appears, therefore, that itraconazole, though not the final answer to management of deep mycoses, is certainly a major improvement on previous drugs. PMID:1319312

Bayles, M A

1992-01-01

54

Rodents as potential couriers for bioterrorism agents.  

PubMed

Many pathogens that can cause major public health, economic, and social damage are relatively easily accessible and could be used as biological weapons. Wildlife is a natural reservoir for many potential bioterrorism agents, and, as history has shown, eliminating a pathogen that has dispersed among wild fauna can be extremely challenging. Since a number of wild rodent species live close to humans, rodents constitute a vector for pathogens to circulate among wildlife, domestic animals, and humans. This article reviews the possible consequences of a deliberate spread of rodentborne pathogens. It is relatively easy to infect wild rodents with certain pathogens or to release infected rodents, and the action would be difficult to trace. Rodents can also function as reservoirs for diseases that have been spread during a bioterrorism attack and cause recurring disease outbreaks. As rats and mice are common in both urban and rural settlements, deliberately released rodentborne infections have the capacity to spread very rapidly. The majority of pathogens that are listed as potential agents of bioterrorism by the Centers for Disease Control and Prevention and the National Institute of Allergy and Infectious Diseases exploit rodents as vectors or reservoirs. In addition to zoonotic diseases, deliberately released rodentborne epizootics can have serious economic consequences for society, for example, in the area of international trade restrictions. The ability to rapidly detect introduced diseases and effectively communicate with the public in crisis situations enables a quick response and is essential for successful and cost-effective disease control. PMID:23971813

Lõhmus, Mare; Janse, Ingmar; van de Goot, Frank; van Rotterdam, Bart J

2013-09-01

55

Tropical Tree Seed Manual.  

National Technical Information Service (NTIS)

The Tropical Tree Seed Manual is a one-volume reference manual for students, technicians, and scientists that provides comprehensive internationally compiled data about tropical trees. The emphasis is on species of the Americas; however, a number of tropi...

J. A. Vozzo

2002-01-01

56

Orthopox virus infections in Eurasian wild rodents.  

PubMed

The genus Orthopoxvirus includes variola (smallpox) virus and zoonotic cowpox virus (CPXV). All orthopoxviruses (OPV) are serologically cross-reactive and cross-protective, and after the cessation of smallpox vaccination, CPXV and other OPV infections represent an emerging threat to human health. In this respect CPXV, with its reservoir in asymptomatically infected wild rodents, is of special importance. In Europe, clinical cowpox has been diagnosed in both humans and animals. The main objective of this study was to elucidate the prevalence of OPV infections in wild rodents in different parts of Eurasia and to compare the performance of three real-time polymerase chain reaction (PCR) methods in detecting OPV DNA in wildlife samples. We investigated 962 wild rodents from Northern Europe (Finland), Central Europe (Germany), and Northern Asia (Siberia, Russia) for the presence of OPV antibodies. According to a CPXV antigen-based immunofluorescence assay, animals from 13 of the 17 locations (76%) showed antibodies. Mean seroprevalence was 33% in Finland (variation between locations 0%-69%), 32% in Germany (0%-43%), and 3.2% (0%-15%) in Siberia. We further screened tissue samples from 513 of the rodents for OPV DNA using up to three real-time PCRs. Three rodents from two German and one Finnish location were OPV DNA positive. The amplicons were 96% to 100% identical to available CPXV sequences. Further, we demonstrated OPV infections as far east as the Baikal region and occurring in hamster and two other rodent species, ones previously unnoticed as possible reservoir hosts. Based on serological and PCR findings, Eurasian wild rodents are frequently but nonpersistently infected with OPVs. Results from three real-time PCR methods were highly concordant. This study extends the geographic range and wildlife species diversity in which OPV (or CPXV) viruses are naturally circulating. PMID:21453121

Kinnunen, Paula M; Henttonen, Heikki; Hoffmann, Bernd; Kallio, Eva R; Korthase, Christian; Laakkonen, Juha; Niemimaa, Jukka; Palva, Airi; Schlegel, Mathias; Ali, Hanan Sheikh; Suominen, Paula; Ulrich, Rainer G; Vaheri, Antti; Vapalahti, Olli

2011-08-01

57

The Fecal Viral Flora of Wild Rodents  

PubMed Central

The frequent interactions of rodents with humans make them a common source of zoonotic infections. To obtain an initial unbiased measure of the viral diversity in the enteric tract of wild rodents we sequenced partially purified, randomly amplified viral RNA and DNA in the feces of 105 wild rodents (mouse, vole, and rat) collected in California and Virginia. We identified in decreasing frequency sequences related to the mammalian viruses families Circoviridae, Picobirnaviridae, Picornaviridae, Astroviridae, Parvoviridae, Papillomaviridae, Adenoviridae, and Coronaviridae. Seventeen small circular DNA genomes containing one or two replicase genes distantly related to the Circoviridae representing several potentially new viral families were characterized. In the Picornaviridae family two new candidate genera as well as a close genetic relative of the human pathogen Aichi virus were characterized. Fragments of the first mouse sapelovirus and picobirnaviruses were identified and the first murine astrovirus genome was characterized. A mouse papillomavirus genome and fragments of a novel adenovirus and adenovirus-associated virus were also sequenced. The next largest fraction of the rodent fecal virome was related to insect viruses of the Densoviridae, Iridoviridae, Polydnaviridae, Dicistroviriade, Bromoviridae, and Virgaviridae families followed by plant virus-related sequences in the Nanoviridae, Geminiviridae, Phycodnaviridae, Secoviridae, Partitiviridae, Tymoviridae, Alphaflexiviridae, and Tombusviridae families reflecting the largely insect and plant rodent diet. Phylogenetic analyses of full and partial viral genomes therefore revealed many previously unreported viral species, genera, and families. The close genetic similarities noted between some rodent and human viruses might reflect past zoonoses. This study increases our understanding of the viral diversity in wild rodents and highlights the large number of still uncharacterized viruses in mammals.

Phan, Tung G.; Kapusinszky, Beatrix; Wang, Chunlin; Rose, Robert K.; Lipton, Howard L.; Delwart, Eric L.

2011-01-01

58

Tropical Cyclones 1990-Central North Pacific.  

National Technical Information Service (NTIS)

Contents: Central North Pacific Tropical Cyclone Data, 1990; Tropical Storm AKA; Tropical Storm AKA - 24 Hour Forecast Verification; Tropical Storm AKA - 36 Hour Forecast Verification; Tropical Storm AKA - 48 Hour Forecast Verification; Tropical Storm AKA...

A. K. T. Chun R. T. Martin H. E. Rosendal

1991-01-01

59

The MAM rodent model of schizophrenia  

PubMed Central

Rodent models of human disease are essential to obtain a better understanding of disease pathology, the mechanism of action underlying conventional treatments, as well as for the generation of novel therapeutic approaches. There are a number of rodent models of schizophrenia based on either genetic manipulations, acute or sub-chronic drug administration, or developmental disturbances. The prenatal methylazoxymethanol acetate (MAM) rodent model is a developmental disruption model gaining increased attention because it displays a number of histological, neurophysiological and behavioral deficits analogous to those observed in schizophrenia patients. This unit describes the procedures required to safely induce the MAM phenotype in rats. In addition, we describe a simple behavioral procedure, amphetamine-induced hyper-locomotion, which can be utilized to verify the MAM phenotype.

Lodge, Daniel J.

2013-01-01

60

Immunotoxicity testing in non-rodent species.  

PubMed

Evaluation of the immunotoxicity potential of some pharmaceuticals, including immunomodulatory chemicals and biologics, cannot be limited to testing in rodents. Thus, immune function tests have also been applied in studies with non-human primates and more recently dogs that assess various components of the immune system. These assays include TDAR responses with various immunogens, lymphocyte phenotyping, natural-killer cell activity, delayed-type hypersensitivity, and macrophage function assays. Approaches for incorporating immune function testing in non-rodent species, results from these tests, their interpretation and limitations with respect to drug safety assessment will be reviewed. PMID:18958726

Haggerty, Helen G

2007-04-01

61

40 CFR 798.5460 - Rodent heritable translocation assays.  

Code of Federal Regulations, 2010 CFR

...2009-07-01 false Rodent heritable translocation assays. 798.5460 Section 798...Toxicity § 798.5460 Rodent heritable translocation assays. (a) Purpose. This...which manifests as balanced reciprocal translocations in progeny descended from...

2009-07-01

62

40 CFR 798.5460 - Rodent heritable translocation assays.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 true Rodent heritable translocation assays. 798.5460 Section 798...Toxicity § 798.5460 Rodent heritable translocation assays. (a) Purpose. This...which manifests as balanced reciprocal translocations in progeny descended from...

2010-07-01

63

Persistence of brodifacoum in cockroach and woodlice: implications for secondary poisoning during rodent eradications.  

PubMed

When planning rodent eradications, that normally involve the use of the anticoagulant poison brodifacoum, it is imperative to minimise impacts on other "non-target" species that dwell alongside the targeted rodents and may indeed be the intended beneficiaries of the eradication. Such impacts can arise either from primary poisoning when the non-target species ingest bait pellets containing toxicant or by secondary poisoning when the non-target species eats prey that has itself eaten brodifacoum. Cockroaches and woodlice, likely to scavenge bait pellets, are widely distributed on tropical and sub-tropical islands where they are eaten by ground-dwelling birds. Combining work on Henderson Island, South Pacific, site of a recent rat eradication project, and UK laboratory experiments, our study first measured brodifacoum concentrations in cockroaches given temporary ad lib access to poison bait pellets, approximately mimicking the aftermath of bait distribution for a rodent eradication. In two separate experiments using different species/exposure times, the mean brodifacoum concentrations among cockroaches immediately after bait exposure was 262±s.e. 131 and 477±168µgkg(-1) wet weight. Values decreased quickly in the following 2 weeks, and then continued to decline at a slower rate over the following 4 weeks in the more prolonged laboratory experiment. A supplementary experiment with woodlice recorded a similar brodifacoum concentration in the animals at the end of the exposure period, 223±66µgkg(-1), and a similar time course for the post-exposure decline. In the context of rails (Rallidae), a group of birds known to be particularly susceptible to primary brodifacoum poisoning, these results suggested that, in terms of acute exposure, individual birds would need to eat a minimum of their own body weight (and more commonly 2-5 times that) of live cockroaches before facing a 50% risk of death. Therefore, we conclude that in eradication scenarios, acute secondary poisoning is of lower concern for these birds than primary poisoning. PMID:24008155

de L Brooke, M; Cuthbert, R J; Harrison, G; Gordon, C; Taggart, M A

2013-11-01

64

Chemical carcinogenesis: Too many rodent carcinogens  

Microsoft Academic Search

The administration of chemicals at the maximum tolerated dose (MTD) in standard animal cancer tests is postulated to increase cell division (mitogenesis), which in turn increases rates of mutagenesis and thus carcinogenesis. The animal data are consistent with this mechanism, because a high proportionâabout halfâof all chemicals tested (whether natural or synthetic) are indeed rodent carcinogens. The authors conclude that

B. N. Ames; L. S. Gold

1990-01-01

65

Too many rodent carcinogens: Mitogenesis increases mutagenesis  

Microsoft Academic Search

A clarification of the mechanism of carcinogenesis is developing at a rapid rate. This new understanding undermines many assumptions of current regulatory policy toward rodent carcinogens and necessitates rethinking the utility and meaning of routine animal cancer tests. At a recent watershed meeting on carcinogenesis, much evidence was presented suggesting that mitogenesis plays a dominant role in carcinogenesis. Our own

B. N. Ames; L. S. Gold

1990-01-01

66

Rodent models for human polycystic ovary syndrome.  

PubMed

Polycystic ovary syndrome (PCOS) is the most frequent female endocrine disorder, affecting 5%-10% of women, causing infertility due to dysfunctional follicular maturation and ovulation, distinctive multicystic ovaries and hyperandrogenism, together with metabolic abnormalities including obesity, hyperinsulinism, an increased risk of type 2 diabetes, and cardiovascular disease. The etiology of PCOS is unclear, and decisive clinical studies are limited by ethical and logistic constraints. Consequently treatment is palliative rather than curative and focuses on symptomatic approaches. Hence, a suitable animal model could provide a valuable means with which to study the pathogenesis of the characteristic reproductive and metabolic abnormalities and thereby identify novel and more effective treatments. So far there is no consensus on the best experimental animal model, which should ideally reproduce the key features associated with human PCOS. The prenatally androgenized rhesus monkey displays many characteristics of the human condition, including hyperandrogenism, anovulation, polycystic ovaries, increased adiposity, and insulin insensitivity. However, the high cost of nonhuman primate studies limits the practical utility of these large-animal models. Rodent models, on the other hand, are inexpensive, provide well-characterized and stable genetic backgrounds readily accessible for targeted genetic manipulation, and shorter reproductive life spans and generation times. Recent rodent models display both reproductive and metabolic disturbances associated with human PCOS. This review aimed to evaluate the rodent models reported to identify the advantages and disadvantages of the distinct rodent models used to investigate this complex endocrine disorder. PMID:22337333

Walters, Kirsty A; Allan, Charles M; Handelsman, David J

2012-05-01

67

Mycoplasmas and their role as rodent pathogens  

Microsoft Academic Search

SUMMARY Mycoplasmas are the smallest known free-living form of life, and differ from bacteria in a number of characteristics. They are widely distributed in the animal kingdom and may give rise to both acute and latent infections as well as being present as normal flora. The three principal rodent pathogens so far described are Mycoplasma pulmonis, Mycoplasma arthritidis and Mycoplasma

R. J. Fallon

1967-01-01

68

Towards sustainable management of rodents in organic animal husbandry  

Microsoft Academic Search

From 26 to 28 May 2004 an international seminar was held in Wageningen, the Netherlands, about current knowledge and advice on rodent management on organic pig and poultry farms in Western Europe. This paper summarizes the discussions. Rodent management is necessary to protect the food production chain from health hazards to livestock and humans. Some organic farmers prefer biological rodent

B. G. Meerburg; M. Bonde; F. W. A. Brom; S. Endepols; A. N. Jensen; H. Leirs; J. Lodal; G. R. Singleton; H.-J. Pelz; T. B. Rodenburg; A. Kijlstra

2004-01-01

69

Towards sustainable management of rodents in organic animal husbandry  

Microsoft Academic Search

From 26 to 28 May 2004 an international seminar was held in Wageningen, the Netherlands, about current knowledge and advice on rodent management on organic pig and poultry farms in Western Europe. This paper summarizes the discussions. Rodent management is necessary to protect the food production chain from health hazards to livestock and humans. Some organic farmers prefer biological rodent

B. G. Meerburg; M. Bonde; F. W. A. Brom; S. Endepols; A. N. Jensen; H. Leirs; J. Lodal; G. R. Singleton; H.-J. Pelz; T. B. Rodenburg; A. Kijlstra

2005-01-01

70

Tropical Cyclone Forecasters Reference Guide. 3. Tropical Cyclone Formation.  

National Technical Information Service (NTIS)

One of the keys to safe and successful naval operations in the tropics is a thorough understanding of tropical meteorology. The Tropical Cyclone Reference Guide is designed primarily as a ready reference for midlatitude forecasters required to provide tro...

R. A. Jeffries R. J. Miller

1993-01-01

71

Novel Rodent Models for Macular Research  

PubMed Central

Background Many disabling human retinal disorders involve the central retina, particularly the macula. However, the commonly used rodent models in research, mouse and rat, do not possess a macula. The purpose of this study was to identify small laboratory rodents with a significant central region as potential new models for macular research. Methodology/Principal Findings Gerbillus perpallidus, Meriones unguiculatus and Phodopus campbelli, laboratory rodents less commonly used in retinal research, were subjected to confocal scanning laser ophthalmoscopy (cSLO), fluorescein and indocyanine green angiography, and spectral-domain optical coherence tomography (SD-OCT) using standard equipment (Heidelberg Engineering HRA1 and Spectralis™) adapted to small rodent eyes. The existence of a visual streak-like pattern was assessed on the basis of vascular topography, retinal thickness, and the topography of retinal ganglion cells and cone photoreceptors. All three species examined showed evidence of a significant horizontal streak-like specialization. cSLO angiography and retinal wholemounts revealed that superficial retinal blood vessels typically ramify and narrow into a sparse capillary net at the border of the respective area located dorsal to the optic nerve. Similar to the macular region, there was an absence of larger blood vessels in the streak region. Furthermore, the thickness of the photoreceptor layer and the population density of neurons in the ganglion cell layer were markedly increased in the visual streak region. Conclusions/Significance The retinal specializations of Gerbillus perpallidus, Meriones unguiculatus and Phodopus campbelli resemble features of the primate macula. Hence, the rodents reported here may serve to study aspects of macular development and diseases like age-related macular degeneration and diabetic macular edema, and the preclinical assessment of therapeutic strategies.

Huber, Gesine; Heynen, Severin; Imsand, Coni; vom Hagen, Franziska; Muehlfriedel, Regine; Tanimoto, Naoyuki; Feng, Yuxi; Hammes, Hans-Peter; Grimm, Christian; Peichl, Leo; Seeliger, Mathias W.; Beck, Susanne C.

2010-01-01

72

[Tropical or non-tropical sprue?].  

PubMed

A 57-year-old Dutch man presented with weight loss and fatigue 6 months after a visit to West Papua, when he had suffered from serious diarrhoea. Macrocytic anaemia and vitamin B12 deficiency were diagnosed. A gastroduodenoscopy with biopsies of the small intestine was performed revealing no macroscopic abnormalities but partial villous atrophy was found microscopically, suggesting tropical sprue or coeliac disease. Antibodies against endomysium and tissue transglutaminase were negative, ruling out coeliac disease. The patient was successfully treated with vitamin B12, folic acid and doxycycline. This case shows that tropical sprue should be considered in the differential diagnosis of chronic diarrhoea in patients with a history of travel in tropical regions. The most frequent medical problem that travelers to the tropics experience is diarrhoea with an incidence of 30%. A small proportion of these patients eventually present with chronic diarrhoea. At that moment, the relation to their previous travelling may not be immediately clear. One of the causes of this chronic diarrhoea to be considered is tropical sprue. PMID:16261708

Sankatsing, S U C; Leguit, R J; ten Kate, F J W; Wetsteyn, J C F M

2005-10-15

73

Chemical constituents and antifilarial activity of Lantana camara against human lymphatic filariid Brugia malayi and rodent filariid Acanthocheilonema viteae maintained in rodent hosts.  

PubMed

Lymphatic filariasis continues to be a major health problem in tropical and subtropical countries. A macrofilaricidal agent capable of eliminating adult filarial parasites is urgently needed. In the present study, we report the antifilarial activity in the extract of stem portion of the plant Lantana camara. The crude extract at 1 g/kg for 5 days by oral route killed 43.05% of the adult Brugia malayi parasites and sterilized 76% of surviving female worms in the rodent model Mastomys coucha. A 34.5% adulticidal activity along with sterilization of 66% of female worms could be demonstrated in the chloroform fraction. Remarkable antifilarial activity was observed in the adult B. malayi transplanted gerbil model where up to 80% of the adult worms could be killed at the same dose and all the surviving female parasites were found sterilized. The extract was also found effective against a subcutaneous rodent filariid Acanthocheilonema viteae maintained in Mastomys coucha, where it exerted strong microfilaricidal (95.04%) and sterilization (60.66%) efficacy with mild macrofilaricidal action. Two compounds, oleanonic acid and oleanolic acid, isolated from hexane and chloroform fractions showed LC100 at 31.25 and 62.5 mug/ml, respectively, on B. malayi in vitro. This is the first ever report on the antifilarial efficacy of Lantana camara. PMID:17061115

Misra, Namita; Sharma, Mithilesh; Raj, Kanwal; Dangi, Anil; Srivastava, Sudhir; Misra-Bhattacharya, Shailja

2007-02-01

74

Cage allocation designs for rodent carcinogenicity experiments.  

PubMed

Cage allocation designs for rodent carcinogenicity experiments are discussed and presented with the goal of avoiding dosage group biases related to cage location. Considerations in selecting a cage design are first discussed in general terms. Specific designs are presented for use in experiments involving three, four, and five dose groups and with one, four, and five rodents per cage. Priorities for balancing treatment groups include horizontal position on shelf and shelf of rack, nearest neighbor balance, and male-female balance. It is proposed that these balance criteria be considered together with practical issues, such as the ability to accurately conform to a design and to determine a sensible and efficient design for each experiment. PMID:1295494

Herzberg, A M; Lagakos, S W

1992-07-01

75

Cage allocation designs for rodent carcinogenicity experiments.  

PubMed

Cage allocation designs for rodent carcinogenicity experiments are discussed and presented with the goal of avoiding dosage group biases related to cage location. Considerations in selecting a cage design are first discussed in general terms. Specific designs are presented for use in experiments involving three, four, and five dose groups and with one, four, and five rodents per cage. Priorities for balancing treatment groups include horizontal position on shelf and shelf of rack, nearest neighbor balance, and male-female balance. It is proposed that these balance criteria be considered together with practical issues, such as the ability to accurately conform to a design and to determine a sensible and efficient design for each experiment. PMID:17539183

Herzberg, A M; Lagakos, S W

1991-12-01

76

Rodent models of TDP-43: Recent advances  

PubMed Central

Recently, missense mutations in the gene TARDBP encoding TDP-43 have been linked to familial ALS. The discovery of genes encoding these RNA binding proteins, such as TDP-43 and FUS/TLS, raised the notion that altered RNA metabolism is a major factor underlying the pathogenesis of ALS. To begin to unravel how mutations in TDP-43 cause dysfunction and death of motor neurons, investigators have employed both gain- and loss-of-function studies in rodent model systems. Here, we will summarize major findings from the initial sets of TDP-43 transgenic and knockout rodent models, identify their limitations, and point to future directions toward clarification of disease mechanism(s) and testing of therapeutic strategies that ultimately may lead to novel therapy for this devastating disease.

Tsao, William; Jeong, Yun Ha; Lin, Sophie; Ling, Jonathan; Price, Donald L.; Chiang, Po-Min; Wong, Philip C.

2013-01-01

77

Evidence for novel hepaciviruses in rodents.  

PubMed

Hepatitis C virus (HCV) is among the most relevant causes of liver cirrhosis and hepatocellular carcinoma. Research is complicated by a lack of accessible small animal models. The systematic investigation of viruses of small mammals could guide efforts to establish such models, while providing insight into viral evolutionary biology. We have assembled the so-far largest collection of small-mammal samples from around the world, qualified to be screened for bloodborne viruses, including sera and organs from 4,770 rodents (41 species); and sera from 2,939 bats (51 species). Three highly divergent rodent hepacivirus clades were detected in 27 (1.8%) of 1,465 European bank voles (Myodes glareolus) and 10 (1.9%) of 518 South African four-striped mice (Rhabdomys pumilio). Bats showed anti-HCV immunoblot reactivities but no virus detection, although the genetic relatedness suggested by the serologic results should have enabled RNA detection using the broadly reactive PCR assays developed for this study. 210 horses and 858 cats and dogs were tested, yielding further horse-associated hepaciviruses but none in dogs or cats. The rodent viruses were equidistant to HCV, exceeding by far the diversity of HCV and the canine/equine hepaciviruses taken together. Five full genomes were sequenced, representing all viral lineages. Salient genome features and distance criteria supported classification of all viruses as hepaciviruses. Quantitative RT-PCR, RNA in-situ hybridisation, and histopathology suggested hepatic tropism with liver inflammation resembling hepatitis C. Recombinant serology for two distinct hepacivirus lineages in 97 bank voles identified seroprevalence rates of 8.3 and 12.4%, respectively. Antibodies in bank vole sera neither cross-reacted with HCV, nor the heterologous bank vole hepacivirus. Co-occurrence of RNA and antibodies was found in 3 of 57 PCR-positive bank vole sera (5.3%). Our data enable new hypotheses regarding HCV evolution and encourage efforts to develop rodent surrogate models for HCV. PMID:23818848

Drexler, Jan Felix; Corman, Victor Max; Müller, Marcel Alexander; Lukashev, Alexander N; Gmyl, Anatoly; Coutard, Bruno; Adam, Alexander; Ritz, Daniel; Leijten, Lonneke M; van Riel, Debby; Kallies, Rene; Klose, Stefan M; Gloza-Rausch, Florian; Binger, Tabea; Annan, Augustina; Adu-Sarkodie, Yaw; Oppong, Samuel; Bourgarel, Mathieu; Rupp, Daniel; Hoffmann, Bernd; Schlegel, Mathias; Kümmerer, Beate M; Krüger, Detlev H; Schmidt-Chanasit, Jonas; Setién, Alvaro Aguilar; Cottontail, Veronika M; Hemachudha, Thiravat; Wacharapluesadee, Supaporn; Osterrieder, Klaus; Bartenschlager, Ralf; Matthee, Sonja; Beer, Martin; Kuiken, Thijs; Reusken, Chantal; Leroy, Eric M; Ulrich, Rainer G; Drosten, Christian

2013-01-01

78

[Vacation and tropical dermatoses].  

PubMed

Besides fever and diarrhea, skin diseases are the third most common cause of morbidity in returning travelers after a stay in a tropical country. Approximately one- quarter of these dermatological symptoms can be referred to a classical tropical disease. The majority are of infectious origin. Often only the clinical appearance leads to the diagnosis of a tropical disease as myiasis, cutaneous larva migrans, tungiasis or cutaneous leishmaniasis. Not infrequently the dermatological symptoms lead to the diagnosis of a primarily systemic tropical disease. For example, an eschar with or without a rash might lead to the diagnosis of a South African tick bite fever caused by Rickettsia africae days before serology may turn positive. Less common tropical skin diseases such as lymphatic filariasis and loiasis need to be considered in returning long-term travelers and immigrants. PMID:22532262

Fischer, M; Reinel, D

2012-05-01

79

Spontaneous Type 2 Diabetic Rodent Models  

PubMed Central

Diabetes mellitus, especially type 2 diabetes (T2DM), is one of the most common chronic diseases and continues to increase in numbers with large proportion of health care budget being used. Many animal models have been established in order to investigate the mechanisms and pathophysiologic progress of T2DM and find effective treatments for its complications. On the basis of their strains, features, advantages, and disadvantages, various types of animal models of T2DM can be divided into spontaneously diabetic models, artificially induced diabetic models, and transgenic/knockout diabetic models. Among these models, the spontaneous rodent models are used more frequently because many of them can closely describe the characteristic features of T2DM, especially obesity and insulin resistance. In this paper, we aim to investigate the current available spontaneous rodent models for T2DM with regard to their characteristic features, advantages, and disadvantages, and especially to describe appropriate selection and usefulness of different spontaneous rodent models in testing of various new antidiabetic drugs for the treatment of type 2 diabetes.

Wang, Yang-wei; Sun, Guang-dong; Sun, Jing; Liu, Shu-jun; Wang, Ji; Xu, Xiao-hong; Miao, Li-ning

2013-01-01

80

Inducible rodent models of acquired podocyte diseases.  

PubMed

Glomerular diseases remain the leading cause of chronic and end-stage kidney disease. Significant advances in our understanding of human glomerular diseases have been enabled by the development and better characterization of animal models. Diseases of the glomerular epithelial cells (podocytes) account for the majority of proteinuric diseases. Rodents have been extensively used experimentally to better define mechanisms of disease induction and progression, as well as to identify potential targets and therapies. The development of podocyte-specific genetically modified mice has energized the research field to better understand which animal models are appropriate to study acquired podocyte diseases. In this review we discuss inducible experimental models of acquired nondiabetic podocyte diseases in rodents, namely, passive Heymann nephritis, puromycin aminonucleoside nephrosis, adriamycin nephrosis, liopolysaccharide, crescentic glomerulonephritis, and protein overload nephropathy models. Details are given on the model backgrounds, how to induce each model, the interpretations of the data, and the benefits and shortcomings of each. Genetic rodent models of podocyte injury are excluded. PMID:18784259

Pippin, Jeffrey W; Brinkkoetter, Paul T; Cormack-Aboud, Fionnualla C; Durvasula, Raghu V; Hauser, Peter V; Kowalewska, Jolanta; Krofft, Ronald D; Logar, Christine M; Marshall, Caroline B; Ohse, Takamoto; Shankland, Stuart J

2009-02-01

81

Tropical Storms, Worldwide  

NSDL National Science Digital Library

The University of Hawaii's Mees Solar Observatory, stationed at Haleakala, Maui, provides a wealth of data and images in its Webpages. This page, Tropical Storms Worldwide, gives regional maps and written updates of hurricane, typhoon, and tropical cyclone activity around the globe. The page also features a strike probability calculator where users click on a list of geographic locations or enter map coordinates or a US zip code in order to view the probability of a tropical storm reaching that area. A storm data archive (1994-2000) and printer-friendly .pdf-formatted storm track maps are also available.

1996-01-01

82

Leptospira and Rodents in Cambodia: Environmental Determinants of Infection  

PubMed Central

We investigated infection of rodents and shrews by Leptospira spp. in two localities of Cambodia (Veal Renh, Kaev Seima) and in four types of habitat (forests, non-flooded lands, lowland rain-fed paddy fields, houses) during the wet and the dry seasons. Habitat preference was common, and rodent and shrew species were found only in houses or in rain-fed paddy fields or in forests. Among 649 small mammals trapped belonging to 12 rodent species and 1 shrew species, 71 of 642 animals tested were carriers of Leptospira according to the 16S ribosomal RNA marker used. Rodent infection was higher in low-slope locations, corresponding to rain-fed paddy fields, especially in the rainy season and in Kaev Seima. Rodents (Rattus exulans) and shrews (Suncus murinus) inhabiting households showed significantly low levels of infections, whereas rodents living in and near to forests (shrubby wasteland, orchards) showed high levels of infection.

Ivanova, Svilena; Herbreteau, Vincent; Blasdell, Kim; Chaval, Yannick; Buchy, Philippe; Guillard, Bertrand; Morand, Serge

2012-01-01

83

Leptospira and rodents in Cambodia: environmental determinants of infection.  

PubMed

We investigated infection of rodents and shrews by Leptospira spp. in two localities of Cambodia (Veal Renh, Kaev Seima) and in four types of habitat (forests, non-flooded lands, lowland rain-fed paddy fields, houses) during the wet and the dry seasons. Habitat preference was common, and rodent and shrew species were found only in houses or in rain-fed paddy fields or in forests. Among 649 small mammals trapped belonging to 12 rodent species and 1 shrew species, 71 of 642 animals tested were carriers of Leptospira according to the 16S ribosomal RNA marker used. Rodent infection was higher in low-slope locations, corresponding to rain-fed paddy fields, especially in the rainy season and in Kaev Seima. Rodents (Rattus exulans) and shrews (Suncus murinus) inhabiting households showed significantly low levels of infections, whereas rodents living in and near to forests (shrubby wasteland, orchards) showed high levels of infection. PMID:22665613

Ivanova, Svilena; Herbreteau, Vincent; Blasdell, Kim; Chaval, Yannick; Buchy, Philippe; Guillard, Bertrand; Morand, Serge

2012-06-01

84

An Overview of Tropical Meteorology  

NSDL National Science Digital Library

This distance learning course is a committed effort to provide forecasters with a better understanding of the meteorological processes in the tropics and lead to more advanced study in tropical meteorology. It also aims to stimulate future research focused on forecasting problems in the tropics. The modules that comprise this course provide introductions to the atmospheric processes in the tropics and recent developments in the field of tropical meteorology.

2009-01-01

85

Behavioral properties of Balanites aegyptiaca in rodents  

Microsoft Academic Search

Ethnopharmacological relevanceBalanites aegyptiaca is a native plant from the dry tropical areas of Africa and Arabia. It has been used in traditional medicine to treat psychoses, epilepsy, rheumatism and for the management of cough, liver and spleen conditions for many years. The plant is also used as antihelmintic and molluscicide.

J. Ya’u; U. N. Abdulmalik; A. H. Yaro; B. A. Chindo; J. A. Anuka; I. M. Hussaini

2011-01-01

86

Control of Domestic Rats & Mice, Training Guide--Rodent Control Series.  

ERIC Educational Resources Information Center

As one booklet in a series on rodent control, this training guide has been developed to assist administrators, rodent-control operators, and others responsible for rodent-control operations in the training of employees in this field. Topics covered include rodents and human welfare, description and habits of domestic rats and mice, rodent-borne…

Bjornson, Bayard F.; And Others

87

Susceptibility of laboratory rodents to Trichinella papuae.  

PubMed

Members of the genus Trichinella are small nematodes that can infect a wide range of animal hosts. However, their infectivity varies depending on the parasite and host species combination. In this study, we examined the susceptibility of 4 species of laboratory rodents, i.e., mice, rats, hamsters, and gerbils to Trichinella papuae, an emerging non-encapsulated Trichinella species. Trichinella spiralis and Trichinella pseudospiralis were also included in this study for comparison. Fifteen animals of each rodent species were infected orally with 100 muscle larvae of each Trichinella species. Intestinal worm burden was determined at day 6 and 10 post-inoculation (PI). The numbers of muscle larvae were examined at day 45 PI. The reproductive capacity index (RCI) of the 3 Trichinella species in different rodent hosts was determined. By day 6 PI, 33.2-69.6% of the inoculated larvae of the 3 Trichinella species became adult worms in the small intestines of the host animals. However, in rats, more than 96% of adult worms of all 3 Trichinella species were expelled from the gut by day 10 PI. In gerbils, only 4.8-18.1% of adult worms were expelled by day 10 PI. In accordance with the intestinal worm burden and the persistence of adults, the RCI was the highest in gerbils with values of 241.5±41.0 for T. papuae, 432.6±48 for T. pseudospiralis, and 528.6±20.6 for T. spiralis. Hamsters ranked second and mice ranked third in susceptibility in terms of the RCI, Rats yielded the lowest parasite RCI for all 3 Trichinella species. Gerbils may be an alternative laboratory animal for isolation and maintenance of Trichinella spp. PMID:24516265

Sadaow, Lakkhana; Intapan, Pewpan M; Boonmars, Thidarut; Morakote, Nimit; Maleewong, Wanchai

2013-12-01

88

Deforestation in the Tropics  

Microsoft Academic Search

Government policies that encourage exploitation--in particular excessive logging and clearing for ranches and farms--are largely to blame for the accelerating destruction of tropical forests. This paper surveys the problem in detail and briefly recommends potential solutions.

Robert Repetto

1990-01-01

89

Tropical Storm Don  

NASA Video Gallery

GOES-13 data was compiled into an animation by the NASA GOES Project at NASA Goddard that shows the development of Tropical Storm Don in the southern Gulf of Mexico, west of Cuba. The animation run...

90

Hurricanes/Tropical Cyclones  

MedlinePLUS

... Research Links: + NASA's Sea Surface Temperature site + NASA Satellite Hurricane Data Website for Scientists + NASA African Monsoon ... NOAA Hurricane Research Division + Hurricane Storm Names + NOAA Satellite Service Division (SSD) + NOAA Tropical Analysis and Forecast ...

91

Deforestation in the Tropics  

SciTech Connect

Government policies that encourage exploitation--in particular excessive logging and clearing for ranches and farms--are largely to blame for the accelerating destruction of tropical forests. This paper surveys the problem in detail and briefly recommends potential solutions.

Repetto, R. (World Resources Institute, Washington, DC (USA))

1990-04-01

92

Tropical Cyclone Nargis: 2008  

NASA Video Gallery

This new animation, developed with the help of NASA's Pleiades supercomputer, illustrates how tropical cyclone Nargis formed in the Indian Ocean's Bay of Bengal over several days in late April 2008...

93

[Nematodes of rodents from Jelenia Góra district].  

PubMed

The paper presents a survey of nematodes found in 49 rodents of 4 species from 17 localities of the Jelenia Góra district (SW Poland). The following parasites were found: Heligmosomoides polygyrus (Dujardin, 1845) Boulanger, 1922; Heligmosomoides glareoli Baylis, 1928; Heligmosomum mixtum Schulz, 1929; Heligmosomoides sp.; Heligmosomidae gen. sp.; Trichostrongyloidea gen. sp.; Syphacia frederici Roman, 1945; Syphacia montana Yamaguti, 1943; Syphacia stroma (Linstow, 1884) Morgan, 1932; Syphacia nigeriana Baylis, 1928; Aonchoteca murissylvatici (Diesing, 1851) Lopez-Neyra, 1947; Trichuris muris (Schrank, 1788) Hall, 1916. PMID:16865978

Popio?ek, Marcin; Hildebrand, Joanna; Karpi?ska, Marta; Indyk, Franciszek; Paw?owska-Indyk, Aurelia

2004-01-01

94

Tolerance in the Tropics  

NSDL National Science Digital Library

Although temperatures are predicted to rise the most in northern latitudes due to global warming, tropical plants and animals might have the most difficult time adapting to climate change. This radio broadcast explains how temperature varies by only a couple of degrees annually in the tropics, and organisms there have a narrow range of temperature tolerance. The clip is 2 minutes in length and is available in MP3 format.

Katt-Reinders, Elizabeth

2010-11-17

95

Predicting tropical cyclone activity  

NASA Astrophysics Data System (ADS)

Tropical cyclones rank as the costliest natural disaster in the United States. They are also the most expensive and deadly natural catastrophe affecting much of southeast Asia. Skilful seasonal and intraseasonal forecasts of tropical cyclone activity can benefit society, business and government by reducing - through the available lead-time - the risk, uncertainty and financial volatility associated with varying active and inactive storm seasons. We review the extended-range prediction of seasonal tropical cyclone activity in the North Atlantic and Northwest Pacific. A number of groups and ventures now issue such forecasts. We compare the methodology and performance of these different models. In particular we examine how they performed in 2002 and, where possible, assess their independent hindcast skill over the period 1987-2001 at monthly leads out to 9 months. We consider the potential for (1) forecasting seasonal tropical cyclone landfalling activity and financial loss for the US, Caribbean Lesser Antilles and southeast Asia, (2) intraseasonal tropical cyclone forecasts. We provide the latest outlooks for tropical cyclone activity in 2003.

Saunders, M. A.

2003-04-01

96

Neglected Tropical Diseases outside the Tropics  

PubMed Central

Background The neglected tropical diseases (NTDs) cause significant morbidity and mortality worldwide. Due to the growth in international travel and immigration, NTDs may be diagnosed in countries of the western world, but there has been no specific focus in the literature on imported NTDs. Methods Retrospective study of a cohort of immigrants and travelers diagnosed with one of the 13 core NTDs at a Tropical Medicine Referral Unit in Spain during the period April 1989-December 2007. Area of origin or travel was recorded and analyzed. Results There were 6168 patients (2634 immigrants, 3277 travelers and 257 VFR travelers) in the cohort. NTDs occurred more frequently in immigrants, followed by VFR travelers and then by other travelers (p<0.001 for trend). The main NTDs diagnosed in immigrants were onchocerciasis (n?=?240, 9.1%) acquired mainly in sub-Saharan Africa, Chagas disease (n?=?95, 3.6%) in immigrants from South America, and ascariasis (n?=?86, 3.3%) found mainly in immigrants from sub-Saharan Africa. Most frequent NTDs in travelers were: schistosomiasis (n?=?43, 1.3%), onchocerciasis (n?=?17, 0.5%) and ascariasis (n?=?16, 0.5%), and all were mainly acquired in sub-Saharan Africa. The main NTDs diagnosed in VFR travelers were onchocerciasis (n?=?14, 5.4%), and schistosomiasis (n?=?2, 0.8%). Conclusions The concept of imported NTDs is emerging as these infections acquire a more public profile. Specific issues such as the possibility of non-vectorial transmission outside endemic areas and how some eradication programmes in endemic countries may have an impact even in non-tropical western countries are addressed. Recognising NTDs even outside tropical settings would allow specific prevention and control measures to be implemented and may create unique opportunities for research in future.

Norman, Francesca F.; Perez de Ayala, Ana; Perez-Molina, Jose-Antonio; Monge-Maillo, Begona; Zamarron, Pilar; Lopez-Velez, Rogelio

2010-01-01

97

In vitro anthelmintic effects of cysteine proteinases from plants against intestinal helminths of rodents.  

PubMed

Infections with gastrointestinal (GI) nematodes are amongst the most prevalent worldwide, especially in tropical climates. Control of these infections is primarily through treatment with anthelmintic drugs, but the rapid development of resistance to all the currently available classes of anthelmintic means that alternative treatments are urgently required. Cysteine proteinases from plants such as papaya, pineapple and fig are known to be substantially effective against three rodent GI nematodes, Heligmosomoides polygyrus, Trichuris muris and Protospirura muricola, both in vitro and in vivo. Here, based on in vitro motility assays and scanning electron microscopy, we extend these earlier reports, demonstrating the potency of this anthelmintic effect of plant cysteine proteinases against two GI helminths from different taxonomic groups - the canine hookworm, Ancylostoma ceylanicum, and the rodent cestode, Rodentolepis microstoma. In the case of hookworms, a mechanism of action targeting the surface layers of the cuticle indistinguishable from that reported earlier appears to be involved, and in the case of cestodes, the surface of the tegumental layers was also the principal location of damage. Hence, plant cysteine proteinases have a broad spectrum of activity against intestinal helminths (both nematodes and cestodes), a quality that reinforces their suitability for development as a much-needed novel treatment against GI helminths of humans and livestock. PMID:18005461

Stepek, Gillian; Lowe, Ann E; Buttle, David J; Duce, Ian R; Behnke, Jerzy M

2007-12-01

98

Kinetics of Spermatogenesis in the Wild Squirrel Funambulus palmarum (Linnaeus)  

Microsoft Academic Search

The paper describes in detail the morphology and kinetics of germ cell associations, pattern of mitotic divisions frequency distribution of different cellular associations (stages) and percent degeneration of various germ cells i n the squirrel in which spermatogenesis in adults occurs all year round. Eighteen steps of spermiogenesis were identified based on the development of the acrosomal system using PAS-haematoxylin.

S. B. Patil; S. K. Saidapur

1991-01-01

99

Genetic Variants of Orientia tsutsugamushi in Domestic Rodents, Northern China  

PubMed Central

We screened Orientia tsutsugamushi from 385 domestic rodents and 19 humans with scrub typhus in rural Tai’an District, Shandong Province, a new scrub typhus epidemic area in northern China. Sequence analysis identified 7 genotypes in the rodents, of which 2 were also identified in the humans.

Zhang, Meng; Wang, Xian-Jun; Li, Zhong; Ding, Lei; Ding, Shu-Jun; Yang, Hui-Li

2013-01-01

100

Bioinformatics toolbox for narrowing rodent quantitative trait loci  

Microsoft Academic Search

Quantitative trait locus (QTL) analysis is a powerful method for localizing disease genes, but identifying the causal gene remains difficult. Rodent models of disease facilitate QTL gene identification, and causal genes underlying rodent QTL are often associated with the corresponding human diseases. Recently developed bioinformatics methods, including comparative genomics, combined cross analysis, interval-specific and genome-wide haplotype analysis, followed by sequence

Keith DiPetrillo; Xiaosong Wang; Ioannis M. Stylianou; Beverly Paigen

2005-01-01

101

Lurking in the Shadows: Emerging Rodent Infectious Diseases  

PubMed Central

Rodent parvoviruses, Helicobacter spp., murine norovirus, and several other previously unknown infectious agents have “emerged” in laboratory rodents relatively recently. These agents have been discovered serendipitously or through active investigation of atypical serology results, cell culture contamination, unexpected histopathology, or previously unrecognized clinical disease syndromes. The potential research impact of these agents is not fully known. Infected rodents have demonstrated immunomodulation, tumor suppression, clinical disease (particularly in immunodeficient rodents), and histopathology. Perturbations of organismal and cellular physiology also likely occur. These agents posed unique challenges to laboratory animal resource programs once discovered; it was necessary to develop specific diagnostic assays and an understanding of their epidemiology and transmission routes before attempting eradication, and then evaluate eradication methods for efficacy. Even then management approaches varied significantly, from apathy to total exclusion, and such inconsistency has hindered the sharing and transfer of rodents among institutions, particularly for genetically modified rodent models that may not be readily available. As additional infectious agents are discovered in laboratory rodents in coming years, much of what researchers have learned from experiences with the recently identified pathogens will be applicable. This article provides an overview of the discovery, detection, and research impact of infectious agents recently identified in laboratory rodents. We also discuss emerging syndromes for which there is a suspected infectious etiology, and the unique challenges of managing newly emerging infectious agents.

Besselsen, David G.; Franklin, Craig L.; Livingston, Robert S.; Riley, Lela K.

2013-01-01

102

The structure of rodent faunas associated with arenaviral infections  

PubMed Central

The biogeographical examination of rodent faunas associated with arenaviruses reveals two distinct patterns. Lymphocytic choriomeningitis (LCM) virus is associated primarily with a single murid species, Mus musculus, although it is also known to cause laboratory infections in other species. On the other hand, the arenaviruses from the Western hemisphere are associated exclusively with a large and diverse group of cricetid rodents. Studies to date, although limited, have not demonstrated their association with any other rodent groups, although in South America alone at least twelve other rodent families are known. Evidence at the present time indicates that Lassa virus is only associated with a common African rodent, Mastomys natalensis. From this limited evidence it is as yet difficult to determine whether Lassa virus will follow the pattern of the South American arenaviruses, most of which are known from several species of rodents, or that of LCM virus, which appears to be associated with only a single rodent species. In this paper, the history and structure of South American, Eurasian, and African rodent faunas are described.

Arata, A. A.; Gratz, N. G.

1975-01-01

103

Response to Rodent Saliva by Two Species of Rodentiophagous Snakes  

Microsoft Academic Search

Brown tree snakes (Boiga irregularis) and prairie rattlesnakes (Crotalus viridis) responded with higher rates of tongue flicking to rodent saliva than to water. Both materials were presented on cotton-tipped applicators touched gently to the snakes' lips. Rattlesnakes also struck more frequently at applicators bearing saliva than at control applicators. Since rodents frequently lick themselves during bouts of grooming behavior, saliva

David Chiszar; William Lukas; Hobart M. Smith

1997-01-01

104

PREDICTIVE SIMULATION MODELING FOR ANTIANDROGEN IMPACTS ON RODENT PROSTATE  

EPA Science Inventory

Predictive simulation modeling for antiandrogen impacts on rodent prostate HA Barton1, RW Setzer1, LK Potter1,2 1US EPA, ORD, NHEERL, ETD, PKB, Research Triangle Park, NC and 2Curriculum in Toxicology, UNC, Chapel Hill, NC Changes in rodent prostate weight and functi...

105

Natural selection and the genetic basis of osmoregulation in heteromyid rodents as revealed by RNA-seq.  

PubMed

One adaptation of ecological and evolutionary interest is the extraordinary ability of desert rodents to retain water during waste production. Much is known regarding the unique kidney physiology of kangaroo rats (Dipodomys spp.) and their ability to retain water during waste production, yet the genetic basis of these physiological adaptations is relatively unknown. Herein, we utilized RNA-seq data to conduct a comparative study to identify osmoregulatory genes expressed in heteromyid rodents. We sequenced kidney tissue from two temperate desert species (Dipodomys spectabilis and Chaetodipus baileyi) from two separate subfamilies of the Heteromyidae and compared these transcriptomes to a tropical mesic species (Heteromys desmarestianus) from a third subfamily. The evolutionary history of these subfamilies provided a robust phylogenetic control that allowed us to separate shared evolutionary history from convergence. Using two methods to detect differential expression (DE), we identified 1890 genes that showed consistent patterns of DE between the arid and mesic species. A three-species reciprocal BLAST analysis revealed 3511 sets of putative orthologues that, upon comparison to known Mus musculus sequences, revealed 323 annotated and full-length genic regions. Selection tests displayed evidence of positive selection (dn/ds > 1) on six genes in the two desert species and remained significant for one of these genes after correction for multiple testing. Thus, our data suggest that both the coding sequence and expression of genes have been shaped by natural selection to provide the genetic architecture for efficient osmoregulation in desert-adapted heteromyid rodents. PMID:24754676

Marra, Nicholas J; Romero, Andrea; DeWoody, J Andrew

2014-06-01

106

Prospects of chemosterilant and genetic control of rodents  

PubMed Central

This paper discusses some requirements of an ideal rodent chemosterilant, analyses the advantages of chemosterilants over other control methods, and compares the potential values of chemosterilants that affect females, males, and both sexes. Examples are given of specific situations where chemosterilants will be valuable in rodent control, together with suggested methods of applying them. The theory and practicability of using genetics in rodent control are also discussed. Neither the chemosterilant nor the genetic method is expected to become a panacea, but their eventual application will be a significant advance in rodent-control technology. Since both approaches are based on sound biological principles and are relatively safe, they should be helpful in regulating rodent populations in the future.

Marsh, Rex E.; Howard, Walter E.

1973-01-01

107

Epidemiology of Leptospira Transmitted by Rodents in Southeast Asia  

PubMed Central

Background Leptospirosis is the most common bacterial zoonoses and has been identified as an important emerging global public health problem in Southeast Asia. Rodents are important reservoirs for human leptospirosis, but epidemiological data is lacking. Methodology/Principal Findings We sampled rodents living in different habitats from seven localities distributed across Southeast Asia (Thailand, Lao PDR and Cambodia), between 2009 to 2010. Human isolates were also obtained from localities close to where rodents were sampled. The prevalence of Leptospira infection was assessed by real-time PCR using DNA extracted from rodent kidneys, targeting the lipL32 gene. Sequencing rrs and secY genes, and Multi Locus Variable-number Tandem Repeat (VNTR) analyses were performed on DNA extracted from rat kidneys for Leptospira isolates molecular typing. Four species were detected in rodents, L. borgpetersenii (56% of positive samples), L. interrogans (36%), L. kirschneri (3%) and L. weilli (2%), which were identical to human isolates. Mean prevalence in rodents was approximately 7%, and largely varied across localities and habitats, but not between rodent species. The two most abundant Leptospira species displayed different habitat requirements: L. interrogans was linked to humid habitats (rice fields and forests) while L. borgpetersenii was abundant in both humid and dry habitats (non-floodable lands). Conclusion/Significance L. interrogans and L. borgpetersenii species are widely distributed amongst rodent populations, and strain typing confirmed rodents as reservoirs for human leptospirosis. Differences in habitat requirements for L. interrogans and L. borgpetersenii supported differential transmission modes. In Southeast Asia, human infection risk is not only restricted to activities taking place in wetlands and rice fields as is commonly accepted, but should also include tasks such as forestry work, as well as the hunting and preparation of rodents for consumption, which deserve more attention in future epidemiological studies.

Mielcarek, Mathilde; Tatard, Caroline; Chaval, Yannick; Suputtamongkol, Yupin; Buchy, Philippe; Jittapalapong, Sathaporn; Herbreteau, Vincent; Morand, Serge

2014-01-01

108

Domestic Rodent Control Training Manual: A Training Aid for the Rodent Control Category for Certification of Pesticide Applicators.  

ERIC Educational Resources Information Center

This training manual, designed for training applicants who wish to obtain certification in pesticide application relative to rodent control, covers the following topics: economic factors, public health factors, biological characteristics of domestic rodents, rat and mouse signs, trapping, repellents, poisons, baits, poisoned water, dumps, sewers,…

Childress, William R., Jr.; And Others

109

Carbohydrate Studies in Tropical Sprue.  

National Technical Information Service (NTIS)

The lactose tolerance test is useful for detecting malabsorption in tropical sprue. For this purpose it is superior to a numer of other oral tolerance tests. The generalized disaccharidase deficiency found in tropical sprue appears to be a secondary pheno...

T. W. Sheehy P. R. Anderson B. E. Baggs

1966-01-01

110

Tropical Cyclone Climatology  

NSDL National Science Digital Library

This site contains figures and tables that describe the progress of a typical hurricane season in terms of the total number of tropical systems and hurricanes produced throughout the year in the Atlantic and East Pacific basins. The figures have curves which represent the average cumulative production of all named tropical systems, all hurricanes, and those hurricanes which were Category 3 or stronger in those basins. The tables list benchmark dates when a given number of tropical systems, hurricanes, or category 3 storms should have been generated. In the progress of the average Atlantic or East Pacific season based on 1944-1996 data, they show the date upon which the number of events would normally have occurred.

111

Tropical cyclone formation  

SciTech Connect

The physics of tropical cyclone formation is not well understood, and more is known about the mature hurricane than the formative mechanisms that produce it. It is believed part of the reason for this can be traced to insufficient upper-level atmospheric data. Recent observations suggest that tropical cyclones are initiated by asymmetric interactions associated with migratory upper-level potential vorticity disturbances and low-level disturbances. Favored theories of cyclones formation, however, focus on internal processes associated with cumulus convection and/or air-sea interaction. This work focuses on external mechanisms of cyclone formation and, using both a two- and three-dimensional moist geostrophic momentum model, investigates the role of upper-level potential vorticity disturbances on the formation process. A conceptual model of tropical cyclone formation is proposed, and implications of the theory are discussed. 71 refs., 5 figs., 1 tab.

Montgomery, M.T.; Farrell, B.F. (Harvard Univ., Cambridge, MA (United States))

1993-01-15

112

Endotoxin-induced uveitis in rodents.  

PubMed

Uveitis is a common cause of vision loss, accounting for 10-15 % of all cases of blindness worldwide and affects individuals of all ages, genders, and races. Uveitis represents a broad range of intraocular inflammatory conditions due to complications of autoimmune diseases, bacterial infections, viral infections, and chemical and metabolic injuries. Endotoxin-induced uveitis (EIU) in rodents is an efficient experimental model to investigate the pathological mechanism and pharmacological efficacy of potential drug agents. EIU is characterized by clinically relevant classical signs of inflammation, including inflammatory exudates and cells in the anterior and vitreous chambers. EIU in small animal models such as rats, mice, and rabbits is a short-lived uveal inflammation that can be developed subsequent to administration of bacterial endotoxin, such as lipopolysaccharide. Here, we present a reproducible, reliable, and simplified protocol to induce EIU in mice. This method could be used with similar efficacy for EIU induction in other small animals as well. PMID:23824898

Yadav, Umesh C S; Ramana, Kota V

2013-01-01

113

[Neurosteroidogenesis and exploratory responses in rodents].  

PubMed

We have studied the influence of intraperitoneal introduction of a selective blocker of mitochondrial translocation protein 18kD PK11195 (5 mg/kg), indomethacin (5 and 10 mg/kg), finasteride (5 and 15 mg/kg), and neurosteroid pregnenolone (20 mg/kg) on the exploratory behavior of male BALB/c mice, C57BL/6 mice, and Wistar rats in open-field test. It is found that treatment with PK11195 weakens the exploratory behavior in open-field test in mice of both strains. Finasteride and indomethacin decrease the exploratory responses in rodents regardless of the species or type of stress emotional response phenotype. Pregnenolone possesses activating effect in open-field in open-field test, but enhances the inhibitory effect of finasteride in BALB/c mice. PMID:24791332

2014-01-01

114

Testing the limits of Rodent Sperm Analysis: azoospermia in an otherwise healthy wild rodent population.  

PubMed

By comparing the sperm parameters of small rodents trapped at contaminated terrestrial sites and nearby habitat-matched noncontaminated locations, the patent-pending Rodent Sperm Analysis (RSA) method provides a direct health status appraisal for the maximally chemical-exposed mammalian ecological receptor in the wild. RSA outcomes have consistently allowed for as definitive determinations of receptor health as are possible at the present time, thereby streamlining the ecological risk assessment (ERA) process. Here, we describe the unanticipated discovery, at a contaminated US EPA Superfund National Priorities List site, of a population of Hispid cotton rats (Sigmodon hispidus), with a high percentage of adult males lacking sperm entirely (azoospermia). In light of the RSA method's role in streamlining ERAs and in bringing contaminated Superfund-type site investigations to closure, we consider the consequences of the discovery. The two matters specifically discussed are (1) the computation of a population's average sperm count where azoospermia is present and (2) the merits of the RSA method and its sperm parameter thresholds-for-effect when azoospermia is masked in an otherwise apparently healthy rodent population. PMID:18437443

Tannenbaum, Lawrence V; Thran, Brandolyn H; Willams, Keith J

2009-01-01

115

Acidification in tropical countries  

SciTech Connect

Acidification of the environment--caused by the emission of sulfur and nitrogen oxides into the atmosphere--is one of the most serious side effects of industrialization. This volume provides a thorough introduction to this global problem. A basic overview describes acidification processes occurring in the air, water, and soil, and relates other facts known about the acidification of the tropical environment. There is discussion of potential future impacts of emissions which cause acidification. Includes a series of case studies focusing on acidification problems in specific countries in the tropics.

Rodhe, H.; Herrera, R.

1988-01-01

116

Measuring behaviour in rodents: towards translational neuropsychiatric research.  

PubMed

Rodent behavioural tasks are indispensable to advance the understanding of gene × environment interactions in neuropsychiatric disorders and the discovery of new therapeutic strategies. Yet, the actual translation of rodent data to humans, and thereby the understanding of the pathophysiology of neuropsychiatric disorders is limited. The main reason for the translational flaw is that many behavioural tasks for rodents are based on face or predictive validity, whereas these types of validity often lack a pathophysiological basis. Furthermore, many behavioural tasks for rodents do not implement human task parameters or use task parameters in a controlled manner, whereas they are parameters that provide the environmental challenges to test gene function. The aim of this perspective is to address the status quo of behavioural tasks for rodents, their limitations and their strengths, and the reasons why they could lead to suboptimal translational research. I also suggest an approach to come closer to neuropsychiatric behavioural tasks for rodents, namely a more careful implementation of human task parameters and subdivision of behaviour into perceptional, motivational, activational and switching domains. Finally, I will touch upon behavioural tasks for rodents that are currently lacking and needed to catch up neuropsychiatric research. PMID:22982186

Homberg, Judith R

2013-01-01

117

[Dermatology in the tropics].  

PubMed

The Author reviews the cases diagnosed in the Republic of Panama of Mycetoma, Paracoccidioidosis, Lobo's disease, Chromomycosis, Histoplasmosis, Rhinosporidiosis, Sporotrichosis, Lepra, Rhinoscleroma, and cutaneous and mucocutaneous Leishmaniasis, and mentions the observed clinical manifestations in order to familiarize young physicians with the tropical dermatopathology which occurs in the rural areas of the country. PMID:8668822

Tapia Collantes, A

1995-09-01

118

Rain Forests: Tropical Treasures.  

ERIC Educational Resources Information Center

Ranger Rick's NatureScope is a creative education series dedicated to inspiring in children an understanding and appreciation of the natural world while developing the skills they will need to make responsible decisions about the environment. The topic of this issue is "Rain Forests: Tropical Treasures." Contents are organized into the following…

Braus, Judy, Ed.

1989-01-01

119

People & Tropical Rain Forests.  

ERIC Educational Resources Information Center

Discusses ways people who live in rain forests make a living and some of the products that enrich our lives. Provides activities covering forest people, tropical treats, jungle in the pantry, treetop explorers, and three copyable pages to accompany activities. (Author/RT)

NatureScope, 1989

1989-01-01

120

Tropical Atlantic Aerosols  

NSDL National Science Digital Library

Students will use real satellite data to determine 1) where the greatest concentrations of aerosols are located during the course of a year in the tropical Atlantic region and 2) their source of origin. This is an inquiry-style lesson where students pull real aerosol data and attempt to identify trends among data sets.

Roettger, Rex; Collection, Nasa -.

121

Tropical Storm Cristobal  

NSDL National Science Digital Library

This animation shows Tropical Storm Cristobal on August 7, 2002 . Cristobal was located east of St. Augustine, Florida. The storm has had a maximum sustained wind speed of 45 MPH.Cristobal is expected to move east-northeast within the next 24 hours.

Perkins, Lori; Halverson, Jeff

2002-08-07

122

Assessing Tropical Cyclone Damage  

NASA Astrophysics Data System (ADS)

Landfalling tropical cyclones impact large coastal and inland areas causing direct damage due to winds, storm-surge flooding, tornadoes, and precipitation; as well as causing substantial indirect damage such as electrical outages and business interruption. The likely climate change impact of increased tropical cyclone intensity, combined with increases in exposure, bring the possibility of increased damage in the future. A considerable amount of research has focused on modeling economic damage due to tropical cyclones, and a series of indices have been developed to assess damages under climate change. We highlight a number of ways this research can be improved through a series of case study analyses. First, historical loss estimates are revisited to properly account for; time, impacted regions, the source of damage by type, and whether the damage was direct/indirect and insured/uninsured. Second, the drivers of loss from both the socio-economic and physical side are examined. A case is made to move beyond the use of maximum wind speed to more stable metrics and the use of other characteristics of the wind field such as direction, degree of gustiness, and duration is explored. A novel approach presented here is the potential to model losses directly as a function of climate variables such as sea surface temperature, greenhouse gases, and aerosols. This work is the first stage in the development of a tropical cyclone loss model to enable projections of losses under scenarios of both socio-economic change (such as population migration or altered policy) and physical change (such as shifts in tropical cyclone activity one from basin to another or within the same basin).

Done, J.; Czajkowski, J.

2012-12-01

123

Allocentric directional processing in the rodent and human retrosplenial cortex.  

PubMed

Head direction (HD) cells in the rodent brain have been investigated for a number of years, providing us with a detailed understanding of how the rodent brain codes for allocentric direction. Allocentric direction refers to the orientation of the external environment, independent of one's current (egocentric) orientation. The presence of neural activity related to allocentric directional coding in humans has also been noted but only recently directly tested. Given the current status of both fields, it seems beneficial to draw parallels between this rodent and human research. We therefore discuss how findings from the human retrosplenial cortex (RSC), including its "translational function" (converting egocentric to allocentric information) and ability to code for permanent objects, compare to findings from the rodent RSC. We conclude by suggesting critical future experiments that derive from a cross-species approach to understanding the function of the human RSC. PMID:24672459

Knight, Rebecca; Hayman, Robin

2014-01-01

124

Biology of Arboreal Rodents in Douglas-Fir Forests.  

National Technical Information Service (NTIS)

Arboreal rodents in Douglas-fir forests west of the Cascade crest in Oregon and Washington include (listed in decreasing order of dependence on trees) red tree vole (Phenacomys longicaudus), northern flying squirrel (Glaucomys sabrinus), Douglas' squirrel...

A. B. Carey

1991-01-01

125

Primary Rodent and Lightning Protective Sheath for Lightguide Cable.  

National Technical Information Service (NTIS)

A new cable sheath system has been developed for fiber optic cables having strength elements in the sheath. This new primary sheath offers rodent, lightning, and mechanical protection in a configuration much smaller and lighter than previous designs using...

M. R. Reynolds C. J. Arroyo M. D. Kinard

1986-01-01

126

Rodent Water Dispensing System for Use in Hypobaric Chambers.  

National Technical Information Service (NTIS)

A water dispensing system for rodents has been developed for use in chronic research studies involving hypobaric chambers. The system removes an existing problem that has restricted long-term animal exposures due to limitations inherent in the typical wat...

J. A. Devine A. Cymerman

1986-01-01

127

Allocentric directional processing in the rodent and human retrosplenial cortex  

PubMed Central

Head direction (HD) cells in the rodent brain have been investigated for a number of years, providing us with a detailed understanding of how the rodent brain codes for allocentric direction. Allocentric direction refers to the orientation of the external environment, independent of one’s current (egocentric) orientation. The presence of neural activity related to allocentric directional coding in humans has also been noted but only recently directly tested. Given the current status of both fields, it seems beneficial to draw parallels between this rodent and human research. We therefore discuss how findings from the human retrosplenial cortex (RSC), including its “translational function” (converting egocentric to allocentric information) and ability to code for permanent objects, compare to findings from the rodent RSC. We conclude by suggesting critical future experiments that derive from a cross-species approach to understanding the function of the human RSC.

Knight, Rebecca; Hayman, Robin

2014-01-01

128

CCR-AMI Rodent List (CARL) - Model Search  

Cancer.gov

CCR Home | About CCR | CCR Intranet   • Search Database   • Submit New Model   • Database Committee Related NCI sites:   • Molecular Pathology Unit   • MMHCC   • MMHCC Database   • NCI Mouse Repository CCR-AMI Rodent List (CARL) - Model Search Quick

129

MEASUREMENT OF VENTILATORY FREQUENCY IN UNRESTRAINED RODENTS USING MICROWAVE RADIATION  

EPA Science Inventory

A novel technique for remote determination of breathing frequency in unrestrained rodents using microwave radiation is described. Single mice were placed inside a rectangular waveguide operating at 2450 MHz. Because mice efficiently absorb radio frequency energy at 2450 MHz, any ...

130

Secondary dispersal of Dioscorea japonica (Dioscoreaceae) bulbils by rodents  

Microsoft Academic Search

We examined rodent dispersal of Dioscorea japonica bulbils. Bulbils dispersed by rodents may travel farther from their parent plants than those dispersed by gravity alone.\\u000a To confirm the presence of secondary dispersal and the types of vector, we used an automatic camera to photograph animals\\u000a that approached bulbils. To clarify secondary dispersal distance, we set marked bulbils at eight sites

Inoue Mizuki; Akiko Takahashi

2009-01-01

131

Tracking genome organization in rodents by Zoo-FISH.  

PubMed

The number of rodent species examined by modern comparative genomic approaches, particularly chromosome painting, is limited. The use of human whole-chromosome painting probes to detect regions of homology in the karyotypes of the rodent index species, the mouse and rat, has been hindered by the highly rearranged nature of their genomes. In contrast, recent studies have demonstrated that non-murid rodents display more conserved genomes, underscoring their suitability for comparative genomic and higher-order systematic studies. Here we provide the first comparative chromosome maps between human and representative rodents of three major rodent lineages Castoridae, Pedetidae and Dipodidae. A comprehensive analysis of these data and those published for Sciuridae show (1) that Castoridae, Pedetidae and Dipodidae form a monophyletic group, and (2) that the European beaver Castor fiber (Castoridae) and the birch mouse Sicista betulina (Dipodidae) are sister species to the exclusion of the springhare Pedetes capensis (Pedetidae), thus resolving an enduring trifurcation in rodent higher-level systematics. Our results together with published data on the Sciuridae allow the formulation of a putative rodent ancestral karyotype (2n = 50) that is thought to comprise the following 26 human chromosomal segments and/or segmental associations: HSA1pq, 1q/10p, 2pq, 2q, 3a, 3b/19p, 3c/21, 4b, 5, 6, 7a, 7b/16p, 8p/4a/8p, 8q, 9/11, 10q, 12a/22a, 12b/22b, 13, 14/15, 16q/19q, 17, 18, 20, X and Y. These findings provide insights into the likely composition of the ancestral rodent karyotype and an improved understanding of placental genome evolution. PMID:18266061

Graphodatsky, Alexander S; Yang, Fengtang; Dobigny, Gauthier; Romanenko, Svetlana A; Biltueva, Larisa S; Perelman, Polina L; Beklemisheva, Violetta R; Alkalaeva, Elena Z; Serdukova, Natalya A; Ferguson-Smith, Malcolm A; Murphy, William J; Robinson, Terence J

2008-01-01

132

Low-dose cholecalciferol bait for possum and rodent control  

Microsoft Academic Search

A new low-concentration formulation of Feracol paste containing 0.4% concentration cholecalciferol was tested for efficacy against possums in cage trials, and against possums and rodents in a single unreplicated field trial. A new low-concentration 0.4% cholecalciferol cereal pellet was also tested in the field against possums and rodents. 20 wild-caught possums, held in individual cages, were presented with 15 g

S Hix; P Aylett; L Shapiro; D MacMorran; S Sam; JG Ross; A Miller; SC Ogilvie

2012-01-01

133

Molecular detection of divergent trypanosomes among rodents of Thailand.  

PubMed

Herpetosoma is a homogenous subgenus of several dozen named species that are often described as morphologically indistinguishable T. lewisi-like parasites. These trypanosomes normally infect rodents and utilize fleas as vectors. Although this trypanosome subgenus is considered non-pathogenic to normal hosts, some of them are on rare occasion reported in association with human disease. Recently, a T. lewisi-like infection was detected in a sick Thai infant, thus the objective of this study was to investigate the prevalence of T. lewisi infections among different rodents indigenous to Thailand in order to identify possible sources of human cases. Blood was collected from a total of 276 rodents trapped from urban and rural areas of three Thai provinces between 2006 and 2007. These samples were processed for DNA isolation and tested with a PCR assay universal for the genus Trypanosoma, followed by internal transcribed spacer 1 (ITS-1) sequence analysis to identify infections in positive samples. Herpetosoma known as T. lewisi-like trypanosomes were present among Rattus (14.3%) and Bandicota (18.0%) rodent species and salivarian trypanosomes closely related to T. evansi were detected in Leopoldamys (20%) and Rattus (2.0%) species. Herpetosoma were prevalent among rodents associated with both human and sylvatic habitats, while three of the four salivaria-positive rodents were from a forest biotope. A Herpetosoma ITS-1 sequence amplified from one of these samples was 97.9% identical to that reported for T. lewisi in an experimentally infected rat and 96.4% identical to the sequence amplified from blood from a Thai infant. Habitats where rodents were collected significantly affect rodent infection, at least for T. lewisi, suggesting that the degree of anthropization may influence the transmission of Trypanosoma spp. These results suggest that multiple Herpetosoma species or strains are enzootic to Thailand, and that Rattus and Bandicota species are possible sources of human exposure to these parasites. PMID:17904918

Jittapalapong, S; Inpankaew, T; Sarataphan, N; Herbreteau, V; Hugot, J P; Morand, S; Stich, R W

2008-07-01

134

Cellular scaling rules for rodent brains  

PubMed Central

How do cell number and size determine brain size? Here, we show that, in the order Rodentia, increased size of the cerebral cortex, cerebellum, and remaining areas across six species is achieved through greater numbers of neurons of larger size, and much greater numbers of nonneuronal cells of roughly invariant size, such that the ratio between total neuronal and nonneuronal mass remains constant across species. Although relative cerebellar size remains stable among rodents, the number of cerebellar neurons increases with brain size more rapidly than in the cortex, such that the cerebellar fraction of total brain neurons increases with brain size. In contrast, although the relative cortical size increases with total brain size, the cortical fraction of total brain neurons remains constant. We propose that the faster increase in average neuronal size in the cerebral cortex than in the cerebellum as these structures gain neurons and the rapidly increasing glial numbers that generate glial mass to match total neuronal mass at a fixed glia/neuron total mass ratio are fundamental cellular constraints that lead to the relative expansion of cerebral cortical volume across species.

Herculano-Houzel, Suzana; Mota, Bruno; Lent, Roberto

2006-01-01

135

Diffusion tensor imaging of cocaine treated rodents  

PubMed Central

Studies in cocaine-dependent human subjects have shown differences in white matter on diffusion tensor imaging (DTI) compared to non-drug using controls. It is not known whether the FA differences seen on DTI in white matter regions of cocaine-dependent humans result from a pre-existing predilection for drug use or purely from cocaine abuse. To study the effect of cocaine on brain white matter, DTI was performed on 24 rats after continuous infusion of cocaine or saline for 4 weeks, followed by brain histology. Voxel-based morphometry analysis showed 18% decrease in fractional anisotropy (FA) in the splenium of corpus callosum (CC) in cocaine-administered animals relative to saline controls (P = 0.0001). On histology, significant increase in neurofilament expression (125%, P=0.0044) and decrease in myelin basic protein (40%, P = 0.031) was observed in the same region in cocaine-administered animals. This study supports the hypothesis that chronic cocaine use alters white matter integrity in human CC. Unlike humans, where the FA in the genu differed between cocaine users and non-users, the splenium was affected in rats. These differences between rodent and human findings could be due to a several factors that include differences in the brain structure and function between species and/or the dose, timing, and duration of cocaine administration.

Narayana, Ponnada A.; Ahobila-Vajjula, Pallavi; Ramu, Jaivijay; Herrera, Juan; Steinberg, Joel L.; Moeller, F. Gerard

2009-01-01

136

Navigating actions through the rodent parietal cortex  

PubMed Central

The posterior parietal cortex (PPC) participates in a manifold of cognitive functions, including visual attention, working memory, spatial processing, and movement planning. Given the vast interconnectivity of PPC with sensory and motor areas, it is not surprising that neuronal recordings show that PPC often encodes mixtures of spatial information as well as the movements required to reach a goal. Recent work sought to discern the relative strength of spatial vs. motor signaling in PPC by recording single unit activity in PPC of freely behaving rats during selective changes in either the spatial layout of the local environment or in the pattern of locomotor behaviors executed during navigational tasks. The results revealed unequivocally a predominant sensitivity of PPC neurons to locomotor action structure, with subsets of cells even encoding upcoming movements more than 1 s in advance. In light of these and other recent findings in the field, I propose that one of the key contributions of PPC to navigation is the synthesis of goal-directed behavioral sequences, and that the rodent PPC may serve as an apt system to investigate cellular mechanisms for spatial motor planning as traditionally studied in humans and monkeys.

Whitlock, Jonathan R.

2014-01-01

137

Active vibrissal sensing in rodents and marsupials  

PubMed Central

In rats, the long facial whiskers (mystacial macrovibrissae) are repetitively and rapidly swept back and forth during exploration in a behaviour known as ‘whisking’. In this paper, we summarize previous evidence from rats, and present new data for rat, mouse and the marsupial grey short-tailed opossum (Monodelphis domestica) showing that whisking in all three species is actively controlled both with respect to movement of the animal's body and relative to environmental structure. Using automatic whisker tracking, and Fourier analysis, we first show that the whisking motion of the mystacial vibrissae, in the horizontal plane, can be approximated as a blend of two sinusoids at the fundamental frequency (mean 8.5, 11.3 and 7.3 Hz in rat, mouse and opossum, respectively) and its second harmonic. The oscillation at the second harmonic is particularly strong in mouse (around 22 Hz) consistent with previous reports of fast whisking in that species. In all three species, we found evidence of asymmetric whisking during head turning and following unilateral object contacts consistent with active control of whisker movement. We propose that the presence of active vibrissal touch in both rodents and marsupials suggests that this behavioural capacity emerged at an early stage in the evolution of therian mammals.

Mitchinson, Ben; Grant, Robyn A.; Arkley, Kendra; Rankov, Vladan; Perkon, Igor; Prescott, Tony J.

2011-01-01

138

Seasonal variation of ozone in the tropical lower stratosphere: Southern tropics are different from northern tropics  

NASA Astrophysics Data System (ADS)

examine the seasonal behavior of ozone by using measurements from various instruments including ozonesondes, Aura Microwave Limb Sounder, and Stratospheric Aerosol and Gas Experiment II. We find that the magnitude of the annual variation in ozone, as a percentage of the mean ozone, exhibits a maximum at or slightly above the tropical tropopause. The maximum is larger in the northern tropics than in the southern tropics, and the annual maximum of ozone in the southern tropics occurs 2 months later than that in the northern tropics, in contrast to usual assumption that the tropics can be treated as a horizontally homogeneous region. The seasonal cycles of ozone and other species in this part of the lower stratosphere result from a combination of the seasonal variation of the Brewer-Dobson circulation and the seasonal variation of tropical and midlatitude mixing. In the Northern Hemisphere, the impacts of upwelling and mixing between the tropics and midlatitudes on ozone are in phase and additive. In the Southern Hemisphere, they are not in phase. We apply a tropical leaky pipe model independently to each hemisphere to examine the relative roles of upwelling and mixing in the northern and southern tropical regions. Reasonable assumptions of the seasonal variation of upwelling and mixing yield a good description of the seasonal magnitude and phase in both the southern and northern tropics. The differences in the tracers and transport between the northern and southern tropical stratospheres suggest that the paradigm of well-mixed tropics needs to be revised to consider latitudinal variations within the tropics.

Stolarski, Richard S.; Waugh, Darryn W.; Wang, Lei; Oman, Luke D.; Douglass, Anne R.; Newman, Paul A.

2014-05-01

139

Immunological Mechanisms Mediating Hantavirus Persistence in Rodent Reservoirs  

PubMed Central

Hantaviruses, similar to several emerging zoonotic viruses, persistently infect their natural reservoir hosts, without causing overt signs of disease. Spillover to incidental human hosts results in morbidity and mortality mediated by excessive proinflammatory and cellular immune responses. The mechanisms mediating the persistence of hantaviruses and the absence of clinical symptoms in rodent reservoirs are only starting to be uncovered. Recent studies indicate that during hantavirus infection, proinflammatory and antiviral responses are reduced and regulatory responses are elevated at sites of increased virus replication in rodents. The recent discovery of structural and non-structural proteins that suppress type I interferon responses in humans suggests that immune responses in rodent hosts could be mediated directly by the virus. Alternatively, several host factors, including sex steroids, glucocorticoids, and genetic factors, are reported to alter host susceptibility and may contribute to persistence of hantaviruses in rodents. Humans and reservoir hosts differ in infection outcomes and in immune responses to hantavirus infection; thus, understanding the mechanisms mediating viral persistence and the absence of disease in rodents may provide insight into the prevention and treatment of disease in humans. Consideration of the coevolutionary mechanisms mediating hantaviral persistence and rodent host survival is providing insight into the mechanisms by which zoonotic viruses have remained in the environment for millions of years and continue to be transmitted to humans.

Easterbrook, Judith D.; Klein, Sabra L.

2008-01-01

140

Raintree: Tropical Plant Database  

NSDL National Science Digital Library

Hosted by Raintree, the Tropical Plant Database is authored and maintained by Board Certified Naturopath, Ms. Leslie Taylor to provide accurate information about rainforest plants and to help promote rainforest conservation. Including over 300 pages of documentation on rainforest plants and very well-organized, the Tropical Plant Database lists plants by Common name, Botanical name, Ethnic uses, and Action/disorder. The Database File for each plant includes an illustration and information about family, genus, species, common names, plant description, and more. Visitors can link to great illustrations and photos as well as web resources for each plant including Medline Abstracts, W3 TROPICOS Database, Ethnobotany Database, and Phtyochem Database among others. Plant Database File pages include references as well.

2007-06-15

141

Student Research, Tropical Style!  

NSDL National Science Digital Library

A field trip to a tropical location is used to help students examine the process of scientific research. Each student designs a research project, compiles background material, develops the procedure, and builds, buys, or acquires the necessary equipment. A field study trip to a tropical location allows them to collect their data, while demonstrating that science can be interesting and fun! Conclusions are drawn and the final paper is drafted and submitted several weeks after their return. The main area of concentration is marine ecology, but usually each year an additional research topic is offered depending on the location of the field study. One semester of elective high school science credit is awarded for each year. College credit is also offered.

Monte Morris (Clark County R-1 High School REV)

1995-06-30

142

Tropical fevers: Management guidelines.  

PubMed

Tropical fevers were defined as infections that are prevalent in, or are unique to tropical and subtropical regions. Some of these occur throughout the year and some especially in rainy and post-rainy season. Concerned about high prevalence and morbidity and mortality caused by these infections, and overlapping clinical presentations, difficulties in arriving at specific diagnoses and need for early empiric treatment, Indian Society of Critical Care Medicine (ISCCM) constituted an expert committee to develop a consensus statement and guidelines for management of these diseases in the emergency and critical care. The committee decided to focus on most common infections on the basis of available epidemiologic data from India and overall experience of the group. These included dengue hemorrhagic fever, rickettsial infections/scrub typhus, malaria (usually falciparum), typhoid, and leptospira bacterial sepsis and common viral infections like influenza. The committee recommends a 'syndromic approach' to diagnosis and treatment of critical tropical infections and has identified five major clinical syndromes: undifferentiated fever, fever with rash / thrombocytopenia, fever with acute respiratory distress syndrome (ARDS), fever with encephalopathy and fever with multi organ dysfunction syndrome. Evidence based algorithms are presented to guide critical care specialists to choose reliable rapid diagnostic modalities and early empiric therapy based on clinical syndromes. PMID:24678147

Singhi, Sunit; Chaudhary, Dhruva; Varghese, George M; Bhalla, Ashish; Karthi, N; Kalantri, S; Peter, J V; Mishra, Rajesh; Bhagchandani, Rajesh; Munjal, M; Chugh, T D; Rungta, Narendra

2014-02-01

143

Sex-biased parasitism is not universal: evidence from rodent-flea associations from three biomes.  

PubMed

The distribution of parasites among individual hosts is characterised by high variability that is believed to be a result of variations in host traits. To find general patterns of host traits affecting parasite abundance, we studied flea infestation of nine rodent species from three different biomes (temperate zone of central Europe, desert of Middle East and tropics of East Africa). We tested for independent and interactive effects of host sex and body mass on the number of fleas harboured by an individual host while accounting for spatial clustering of host and parasite sampling and temporal variation. We found no consistent patterns of the effect of host sex and body mass on flea abundance either among species within a biome or among biomes. We found evidence for sex-biased flea infestation in just five host species (Apodemus agrarius, Myodes glareolus, Microtus arvalis, Gerbillus andersoni, Mastomys natalensis). In six rodent species, we found an effect of body mass on flea abundance (all species mentioned above and Meriones crassus). This effect was positive in five species and negative in one species (Microtus arvalis). In M. glareolus, G. andersoni, M. natalensis, and M. arvalis, the relationship between body mass and flea abundance was mediated by host sex. This was manifested in steeper change in flea abundance with increasing body mass in male than female individuals (M. glareolus, G. andersoni, M. natalensis), whereas the opposite pattern was found in M. arvalis. Our findings suggest that sex and body mass are common determinants of parasite infestation in mammalian hosts, but neither of them follows universal rules. This implies that the effect of host individual characteristics on mechanisms responsible for flea acquisition may be manifested differently in different host species. PMID:23636459

Kiffner, Christian; Stanko, Michal; Morand, Serge; Khokhlova, Irina S; Shenbrot, Georgy I; Laudisoit, Anne; Leirs, Herwig; Hawlena, Hadas; Krasnov, Boris R

2013-11-01

144

Rodent model of direct cranial blast injury.  

PubMed

Traumatic brain injury resulting from an explosive blast is one of the most serious wounds suffered by warfighters, yet the effects of explosive blast overpressure directly impacting the head are poorly understood. We developed a rodent model of direct cranial blast injury (dcBI), in which a blast overpressure could be delivered exclusively to the head, precluding indirect brain injury via thoracic transmission of the blast wave. We constructed and validated a Cranium Only Blast Injury Apparatus (COBIA) to deliver blast overpressures generated by detonating .22 caliber cartridges of smokeless powder. Blast waveforms generated by COBIA replicated those recorded within armored vehicles penetrated by munitions. Lethal dcBI (LD(50) ? 515?kPa) was associated with: (1) apparent brainstem failure, characterized by immediate opisthotonus and apnea leading to cardiac arrest that could not be overcome by cardiopulmonary resuscitation; (2) widespread subarachnoid hemorrhages without cortical contusions or intracerebral or intraventricular hemorrhages; and (3) no pulmonary abnormalities. Sub-lethal dcBI was associated with: (1) apnea lasting up to 15?sec, with transient abnormalities in oxygen saturation; (2) very few delayed deaths; (3) subarachnoid hemorrhages, especially in the path of the blast wave; (4) abnormal immunolabeling for IgG, cleaved caspase-3, and ?-amyloid precursor protein (?-APP), and staining for Fluoro-Jade C, all in deep brain regions away from the subarachnoid hemorrhages, but in the path of the blast wave; and (5) abnormalities on the accelerating Rotarod that persisted for the 1 week period of observation. We conclude that exposure of the head alone to severe explosive blast predisposes to significant neurological dysfunction. PMID:21639724

Kuehn, Reed; Simard, Philippe F; Driscoll, Ian; Keledjian, Kaspar; Ivanova, Svetlana; Tosun, Cigdem; Williams, Alicia; Bochicchio, Grant; Gerzanich, Volodymyr; Simard, J Marc

2011-10-01

145

GPM: Hurricanes Beyond the Tropics  

NSDL National Science Digital Library

When New England was hit by Tropical Storm Irene in 2011, there was not a satellite monitoring tropical storms that far north; the Tropical Rainfall Measuring Mission (TRMM) was operating in a band between the 35-degree latitudes. The Global Precipitation Measurement (GPM) mission will change that. GPM will build upon TRMM's capacity by examining a larger swath of Earth with instruments that are more advanced and more sensitive. This video introduces the GPM satellite, its instruments and their capabilities.

146

An Examination of Tropical Neurasthenia  

PubMed Central

The nineteenth century conception of neurasthenia is giving way to a psychological ætiology and classification. Quotations show that the older conception dies hard, and varied physical factors are invoked as causes of tropical neurasthenia. Australian experience shows the physical factors present without “neurasthenia.” It is suggested that mal-adjustment is not physiological but sociological. The possibility of psychoneuroses appearing in the guise of tropical diseases. Effect of selection of personnel in reducing breakdown. The writer doubts the existence of a neurasthenia special to the tropics, and urges that the use of the phrase “tropical neurasthenia” should be discontinued.

Culpin, Millais

1933-01-01

147

European Cloth and "Tropical" Skin:  

PubMed Central

As Britain’s imperial and colonial ambitions intensified toward the end of the nineteenth century, the preservation of white European health in tropical climates became an increasingly important concern. Since at least the seventeenth century, the “tropics” had been seen as spaces holding vast potential wealth but also death and disease. To combat these deadly but desirable landscapes, the British built a considerable commodity culture around the preservation of white European health, and for many, tropical clothing was one of the most important and essential items in their “kits.” This article investigates the composition and use of such clothing in relation to British ideas of health and hygiene in tropical climates. First, it considers debates that ensued over the best material—wool, cotton, linen, silk, or a combination of these materials—and the role of “black” skin and local practice in the development of tropical clothing. Second, it demonstrates the importance of location in any discussion of tropical medicine and hygiene, and the tension and ambiguity that still surrounded British ideas of health and hygiene in the tropical colonies. Third, it argues that tropical clothing was important in the maintenance of climatic etiologies despite advances in parasitology and sanitary science. Finally, it considers the relationship of tropical clothing to the formation of a unique colonial identity. To British men and women embarking for any number of tropical destinations, proper clothing was not a banal and mundane component of their outfitting. For many, the clothing signified a departure from the safe and “civil” climes of Britain for adventure in the expanding tropical empire.

Johnson, Ryan

2009-01-01

148

Methodological considerations for measuring spontaneous physical activity in rodents.  

PubMed

When exploring biological determinants of spontaneous physical activity (SPA), it is critical to consider whether methodological factors differentially affect rodents and the measured SPA. We determined whether acclimation time, sensory stimulation, vendor, or chamber size affected measures in rodents with varying propensity for SPA. We used principal component analysis to determine which SPA components (ambulatory and vertical counts, time in SPA, and distance traveled) best described the variability in SPA measurements. We compared radiotelemetry and infrared photobeams used to measure SPA and exploratory activity. Acclimation time, sensory stimulation, vendor, and chamber size independently influenced SPA, and the effect was moderated by the propensity for SPA. A 24-h acclimation period prior to SPA measurement was sufficient for habituation. Principal component analysis showed that ambulatory and vertical measurements of SPA describe different dimensions of the rodent's SPA behavior. Smaller testing chambers and a sensory attenuation cubicle around the chamber reduced SPA. SPA varies between rodents purchased from different vendors. Radiotelemetry and infrared photobeams differ in their sensitivity to detect phenotypic differences in SPA and exploratory activity. These data highlight methodological considerations in rodent SPA measurement and a need to standardize SPA methodology. PMID:24598463

Teske, Jennifer A; Perez-Leighton, Claudio E; Billington, Charles J; Kotz, Catherine M

2014-05-15

149

Observations on the food habits of some African rodents.  

PubMed

Food habits of four common species of African rodents: the giant rat (Cricetomys gambianus), the black house rat (Rattus rattus), the multimammate rat (Mastomys natalensis) and the pygmy mouse (Mus minutoides) were studied on the basis of stomach content analysis, habitat sampling and experimental trials with caged animals. Vegetable items (especially grass, grains and tubers) formed the bulk of the food of all the species. Oil-palm nuts and kernels were also common in the guts of C. gambianus and M. natalensis. Animal food components of all the rodent species comprised mainly insects (especially ants, crickets etc.). Vertebrate flesh and scales were also well represented in the guts of C. gambianus. Domestic and miscellaneous food items were recorded from R. rattus, most of which were trapped in human and animal shelters. Inorganic gut contents, primarily sand grains, were found in sizeable quantities in more than 70% of the rodents examined. Results of experimental feeding trials with caged rodents showed close correlation with those recorded from field samples, especially in terms of food choices and the relative quantities consumed. The ecological and practical implications of these observations are discussed in the light of the importance of the rodents as agricultural and domestic pests. PMID:7323341

Iwuala, M O; Braide, E I; Maduka, N

1980-12-01

150

Identification of Rodent Homologs of Hepatitis C Virus and Pegiviruses  

PubMed Central

ABSTRACT Hepatitis C virus (HCV) and human pegivirus (HPgV or GB virus C) are globally distributed and infect 2 to 5% of the human population. The lack of tractable-animal models for these viruses, in particular for HCV, has hampered the study of infection, transmission, virulence, immunity, and pathogenesis. To address this challenge, we searched for homologous viruses in small mammals, including wild rodents. Here we report the discovery of several new hepaciviruses (HCV-like viruses) and pegiviruses (GB virus-like viruses) that infect wild rodents. Complete genome sequences were acquired for a rodent hepacivirus (RHV) found in Peromyscus maniculatus and a rodent pegivirus (RPgV) found in Neotoma albigula. Unique genomic features and phylogenetic analyses confirmed that these RHV and RPgV variants represent several novel virus species in the Hepacivirus and Pegivirus genera within the family Flaviviridae. The genetic diversity of the rodent hepaciviruses exceeded that observed for hepaciviruses infecting either humans or non-primates, leading to new insights into the origin, evolution, and host range of hepaciviruses. The presence of genes, encoded proteins, and translation elements homologous to those found in human hepaciviruses and pegiviruses suggests the potential for the development of new animal systems with which to model HCV pathogenesis, vaccine design, and treatment.

Kapoor, Amit; Simmonds, Peter; Scheel, Troels K. H.; Hjelle, Brian; Cullen, John M.; Burbelo, Peter D.; Chauhan, Lokendra V.; Duraisamy, Raja; Sanchez Leon, Maria; Jain, Komal; Vandegrift, Kurt Jason; Calisher, Charles H.; Rice, Charles M.; Lipkin, W. Ian

2013-01-01

151

Old World hantaviruses in rodents in New Orleans, Louisiana.  

PubMed

Seoul virus, an Old World hantavirus, is maintained in brown rats and causes a mild form of hemorrhagic fever with renal syndrome (HFRS) in humans. We captured rodents in New Orleans, Louisiana and tested them for the presence of Old World hantaviruses by reverse transcription polymerase chain reaction (RT-PCR) with sequencing, cell culture, and electron microscopy; 6 (3.4%) of 178 rodents captured--all brown rats--were positive for a Seoul virus variant previously coined Tchoupitoulas virus, which was noted in rodents in New Orleans in the 1980s. The finding of Tchoupitoulas virus in New Orleans over 25 years since its first discovery suggests stable endemicity in the city. Although the degree to which this virus causes human infection and disease remains unknown, repeated demonstration of Seoul virus in rodent populations, recent cases of laboratory-confirmed HFRS in some US cities, and a possible link with hypertensive renal disease warrant additional investigation in both rodents and humans. PMID:24639295

Cross, Robert W; Waffa, Bradley; Freeman, Ashley; Riegel, Claudia; Moses, Lina M; Bennett, Andrew; Safronetz, David; Fischer, Elizabeth R; Feldmann, Heinz; Voss, Thomas G; Bausch, Daniel G

2014-05-01

152

Seven Guideposts for Tropical Rain Forest Education.  

ERIC Educational Resources Information Center

Identifies seven guideposts for tropical rain forest education. Aids teachers in finding structure and creating educational experiences that promote more complete understanding of tropical rain forests. (CCM)

Rillero, Peter

1999-01-01

153

Hypergravity Effects on Rodent Pregnancy and Parturition  

NASA Technical Reports Server (NTRS)

No mammal has yet undergone birth, or parturition, in the microgravity of space. Previous studies (Ronco & Alberts, 2000) have shown that mid-pregnant rat dams exposed to spaceflight (0-g) and landed 48-72 hrs before term successfully delivered robust, healthy offspring Microgravity-exposed dams exhibited twice the expected numbers of labor contractions whereas length of pregnancy, duration of labor, fetal wastage, number of neonates born and litter gender ratios were identical to controls. In the present study, we report the results of rodent pregnancy and parturition at the opposite end of the gravity spectrum, in hypergravity. Dams exposed to either: 1.0-g, 1.5-g, 1.75-g or 2.0-g from Gestational day (G) 11 and throughout the births of their litters had comparable pregnancy and labor durations, fetal wastage, numbers of neonates born and litter Tender ratios. During parturition, hypergravity-exposed dams exhibited significantly fewer labor contractions as compared to 1.0-g controls. Dams that underwent birth in hypergravity had significantly fewer offspring surviving the immediate postpartum period (P1: 1.0-g, 11.92 +/- 2.84; 1.5-g, 10.88 +/- 2.17; 1.75-g, 9.22 +/-1.99; 2.0-g, 8.83 +/- 3.31). Within 24 hrs postpartum, neonatal survival was further diminished in hypergravity [P2: 100% (1.0-g); 96% (1.5-g); 96% (1.75-g); 73% (2.0-g)] and continued to decline (P10: 100%(1.0-g.); 90%(1.5-g); 87%(1.75-g), 40%(2.0-g)]. Neonatal losses stabilized by P5 for the 1.5-g andl.75-g conditions but continued until P9 for the 2.0-g condition. Together, these findings show that postnatal, but not prenatal, survival is compromised following birth in hypergravity, Maternal and neonatal factors that contribute to peri-parturitional vulnerability to altered gravity environments will be discussed.

Ronca, A. E.; Baer, L. A.; Mills, N. A.; Wade, C. E.; Dalton, Bonnie (Technical Monitor)

2002-01-01

154

Desert-Tropicals.com  

NSDL National Science Digital Library

Created by plant enthusiast Philippe Faucon, Desert-Tropicals.com is a well-designed website with information about, and pictures of, over 3,500 plants. Plant lists are organized by scientific and common name, succulents, xeriscape plants, palm trees, herbs, and trees. The plant lists are quite extensive, and each species receives its own description page with a nice close-up photo as well as brief information about family, frost and heat tolerance, sun exposure, origin, propagation, and more. The site also connects to articles, a Bulletin Board, Bookstore, and relevant links.

Faucon, Philippe

155

M-tropic HIV envelope protein gp120 exhibits a different neuropathological profile than T-tropic gp120 in rat striatum  

PubMed Central

Most early human immunodeficiency virus type 1 (HIV-1) strains are macrophage (M)-tropic HIV variants and use the chemokine receptor CCR5 for infection. Neuronal loss and dementia are less severe among individuals infected with M-tropic strains. However, after several years, the T cell (T)-tropic HIV strain, which uses CXCR4 variant, can emerge in conjunction with brain abnormalities, suggesting strain-specific differences in neuropathogenicity. The molecular and cellular mechanisms of such diversity remain under investigation. We have previously demonstrated that HIV envelope protein gp120IIIB, which binds to CXCR4, causes neuronal apoptosis in rodents. Thus, we have used a similar experimental model to examine the neurotoxic effects of M-tropic gp120BaL. Gp120BaL was microinjected in the rat striatum and neuronal apoptosis was examined in the striatum, as well as in anatomically connected areas, such as the somatosensory cortex and the substantia nigra. Gp120BaL promoted neuronal apoptosis and tissue loss that were confined to the striatum. Apoptosis was associated with microglial activation and increased levels of interleukin-1?. Intriguingly, gp120BaL increased brain-derived neurotrophic factor in the striatum. Overall, our data show that gp120BaL demonstrates a different neuropathological profile than gp120IIIB. A better understanding of the pathogenic mechanisms mediating HIV neurotoxicity is vital for developing effective neuroprotective therapies against Acquired Immune Deficiency Syndrome-associated Dementia Complex.

Bachis, Alessia; Cruz, Maria I.; Mocchetti, Italo

2010-01-01

156

Tropical Rainforest Education. ERIC Digest.  

ERIC Educational Resources Information Center

This digest provides four guideposts for tropical rainforest education: (1) structure; (2) location and climate; (3) importance; and (4) conservation of resources. Research is cited and background information provided about the layers of life and the adaptations of life within the tropical rain forest. Aspects of life within and near rain forests…

Rillero, Peter

157

Combating tropical deforestation in Haiti  

SciTech Connect

This article outlines the findings of Tropical Forestry Action Plan (TFAP), which was part of an international initiative on tropical deforestation. Ten specific recommendations are addressed. Haiti has lost more than 97% of its forestland, so emphasis should be placed on replenishing the forest cover.

Pellek, R.

1990-09-01

158

Can shrub cover increase predation risk for a desert rodent?  

USGS Publications Warehouse

Previous research indicates that predation risk may influence activity patterns, habitat partitioning, and community structure of nocturnal desert rodents. Shrub microhabitat is typically considered safer than open microhabitat for these small mammals. We investigated predation risk for Townsend's ground squirrels (Spermophilus townsendii), which are diurnal desert rodents that detect predators visually and use burrows for refuge. Our results suggested that shrub cover may increase risk for these squirrels by decreasing their ability to escape from predators. Our field experiment indicated that running speeds of juvenile squirrels were lower in shrub (Ceratoides lanata) habitat than in open areas. Shrub cover was also associated with shorter predator-detection distances (mammalian and avian) and fewer refuges (burrow entrances per hectare) than in open areas in one year but not in another. Our study demonstrated that the visual and locomotive obstruction of vegetative cover may increase predation risk for diurnal desert rodents and that elements of habitat-dependent risk may be temporally dynamic.

Schooley, R. L.; Sharpe, Peter B.

1996-01-01

159

Imaging Conditioned Fear Circuitry Using Awake Rodent fMRI  

PubMed Central

Functional magnetic resonance imaging (fMRI) is a powerful method for exploring emotional and cognitive brain responses in humans. However rodent fMRI has not previously been applied to the analysis of learned behaviour in awake animals, limiting its use as a translational tool. Here we have developed a novel paradigm for studying brain activation in awake rats responding to conditioned stimuli using fMRI. Using this method we show activation of the amygdala and related fear circuitry in response to a fear-conditioned stimulus and demonstrate that the magnitude of fear circuitry activation is increased following early life stress, a rodent model of affective disorders. This technique provides a new translatable method for testing environmental, genetic and pharmacological manipulations on emotional and cognitive processes in awake rodent models.

Brydges, Nichola M.; Whalley, Heather C.; Jansen, Maurits A.; Merrifield, Gavin D.; Wood, Emma R.; Lawrie, Stephen M.; Wynne, Sara-Madge; Day, Mark; Fleetwood-Walker, Sue; Steele, Douglas; Marshall, Ian; Hall, Jeremy; Holmes, Megan C.

2013-01-01

160

Anatomy and Histology of Rodent and Human Major Salivary Glands  

PubMed Central

Major salivary glands of both humans and rodents consist of three pairs of macroscopic glands: parotid, submandibular, and sublingual. These glands secrete serous, mucous or mixed saliva via the proper main excretory ducts connecting the glandular bodies with the oral cavity. A series of discoveries about the salivary ducts in the 17th century by Niels Stensen (1638–1686), Thomas Wharton (1614–1673), and Caspar Bartholin (1655–1738) established the concept of exocrine secretion as well as salivary glands. Recent investigations have revealed the endocrine functions of parotin and a variety of cell growth factors produced by salivary glands. The present review aims to describe macroscopic findings on the major salivary glands of rodents and the microscopic differences between those of humans and rodents, which review should be of interest to those researchers studying salivary glands.

Amano, Osamu; Mizobe, Kenichi; Bando, Yasuhiko; Sakiyama, Koji

2012-01-01

161

Unexpected primitive rodents in the Quaternary of Argentina  

NASA Astrophysics Data System (ADS)

This article describes the first fossils recorded in the Hernandarias Formation (Pleistocene) in Entre Ríos province (eastern Argentina). They are represented by three teeth assigned to the caviomorph rodents (Rodentia, Mammalia) Aenigmys diamantensis gen. et sp. nov. and Eumysops. To establish the phylogenetic affinities of the two most enigmatic teeth, their enamel microstructure was studied. Aenigmys diamantensis is considered the most primitive taxon of a clade formed by Dinomyidae-Neoepiblemidae-Heptaxodontidae. Evidence of the close relationships among these families also is presented herein. The new fossils reinforce previous hypotheses about the survival of primitive Brazilian taxa after their extinction in the Pampas and Patagonia of southern South America. They also show that the diversity of caviomorph rodents during the Quaternary was greater than supposed and that an important Quaternary extinction, not previously detected, affected several lineages. With the available evidence, it is not possible to determine if these rodents indicate a warm pulse or a particular biogeographic situation in Entre Ríos.

Vucetich, María G.; Vieytes, Emma C.; Verzi, Diego H.; Noriega, Jorge I.; Tonni, Eduardo P.

2005-10-01

162

Rodents for comparative aging studies: from mice to beavers.  

PubMed

After humans, mice are the best-studied mammalian species in terms of their biology and genetics. Gerontological research has used mice and rats extensively to generate short- and long-lived mutants, study caloric restriction and more. Mice and rats are valuable model organisms thanks to their small size, short lifespans and fast reproduction. However, when the goal is to further extend the already long human lifespan, studying fast aging species may not provide all the answers. Remarkably, in addition to the fast-aging species, the order Rodentia contains multiple long-lived species with lifespans exceeding 20 years (naked mole-rat, beavers, porcupines, and some squirrels). This diversity opens great opportunities for comparative aging studies. Here we discuss the evolution of lifespan in rodents, review the biology of slow-aging rodents, and show an example of how the use of a comparative approach revealed that telomerase activity coevolved with body mass in rodents. PMID:19424861

Gorbunova, Vera; Bozzella, Michael J; Seluanov, Andrei

2008-09-01

163

Multiple infections of rodents with zoonotic pathogens in austria.  

PubMed

Abstract Rodents are important reservoirs for a large number of zoonotic pathogens. We examined the occurrence of 11 viral, bacterial, and parasitic agents in rodent populations in Austria, including three different hantaviruses, lymphocytic choriomeningitis virus, orthopox virus, Leptospira spp., Borrelia spp., Rickettsia spp., Bartonella spp., Coxiella burnetii, and Toxoplasma gondii. In 2008, 110 rodents of four species (40 Clethrionomys glareolus, 29 Apodemus flavicollis, 26 Apodemus sylvaticus, and 15 Microtus arvalis) were trapped at two rural sites in Lower Austria. Chest cavity fluid and samples of lung, spleen, kidney, liver, brain, and ear pinna skin were collected. We screened selected tissue samples for hantaviruses, lymphocytic choriomeningitis virus, orthopox viruses, Leptospira, Borrelia, Rickettsia, Bartonella spp., C. burnetii, and T. gondii by RT-PCR/PCR and detected nucleic acids of Tula hantavirus, Leptospira spp., Borrelia afzelii, Rickettsia spp., and different Bartonella species. Serological investigations were performed for hantaviruses, lymphocytic choriomeningitis virus, orthopox viruses, and Rickettsia spp. Here, Dobrava-Belgrade hantavirus-, Tula hantavirus-, lymphocytic choriomeningitis virus-, orthopox virus-, and rickettsia-specific antibodies were demonstrated. Puumala hantavirus, C. burnetii, and T. gondii were neither detected by RT-PCR/PCR nor by serological methods. In addition, multiple infections with up to three pathogens were shown in nine animals of three rodent species from different trapping sites. In conclusion, these results show that rodents in Austria may host multiple zoonotic pathogens. Our observation raises important questions regarding the interactions of different pathogens in the host, the countermeasures of the host's immune system, the impact of the host-pathogen interaction on the fitness of the host, and the spread of infectious agents among wild rodents and from those to other animals or humans. PMID:24915446

Schmidt, Sabrina; Essbauer, Sandra S; Mayer-Scholl, Anne; Poppert, Sven; Schmidt-Chanasit, Jonas; Klempa, Boris; Henning, Klaus; Schares, Gereon; Groschup, Martin H; Spitzenberger, Friederike; Richter, Dania; Heckel, Gerald; Ulrich, Rainer G

2014-07-01

164

Isolation of Pasteurella pneumotropica from rodents in South Africa.  

PubMed Central

Four thousand, five hundred and sixteen rodents of 27 species were captured in widely separated localities in South Africa over a period of ten years. Samples of spleen, lung, heart, liver and rectal tissue with faeces were tested for the presence of zoonotic bacteria and 109 isolations of Pasteurella pneumotropica were made from 11 species. Latent infection with the organism was found to be widespread although there were temporal fluctuations in prevalence. Field and laboratory evidence suggest that P. pneumotropica may be associated with, but not the primary cause of, rodent epizootics in the wild.

Shepherd, A. J.; Leman, P. A.; Barnett, R. J.

1982-01-01

165

Prevalence and diversity of Bartonella in rodents of northern Thailand: a comparison with Bartonella in rodents from southern China.  

PubMed

We report results of the first study to investigate the distribution and diversity of Bartonella in rodents from Thailand. Whole blood from 195 rodents, representing six species, was tested for the presence of Bartonella species using standard culture techniques. Isolates were obtained from 17 (8.7%) of the samples, and 14 of those isolates represented distinct strains, based upon partial sequencing of the citrate synthase (gltA) gene. Phylogenetic analysis of the isolates and other Bartonella species indicated that five unique isolates from Bandicota indica form a cluster that may represent a new Bartonella species. Two additional isolates from B. indica clustered together, and were nearly identical to an isolate from Apodemus draco collected in southern China. Importantly, a number of the isolates from Thailand rodents are closely related to B. grahamii and B. elizabethae, species which have been associated with human illness. PMID:15100459

Castle, Kevin T; Kosoy, Michael; Lerdthusnee, Kriangkrai; Phelan, Lori; Bai, Ying; Gage, Kenneth L; Leepitakrat, Warisa; Monkanna, Taweesak; Khlaimanee, Nittaya; Chandranoi, Kirkvich; Jones, James W; Coleman, Russell E

2004-04-01

166

Tropical myeloneuropathies revisited.  

PubMed

An interesting neurological syndrome, characterized by recurrent optic neuritis, cervical myelopathy from syringomyelia, paraparesis, amenorrhea-galactorrhea, and other endocrine problems, has been described among young black women in the French West Indies. The etiology remains unknown, but possible links with Devic's disease, acute disseminated encephalomyelitis, and neurotoxicity from quinolines in Annona muricata teas have been postulated. The largest epidemic of neuropathy in this century occurred in Cuba in 1991-1994. Clinical features and etiologic studies are reviewed. Its primary cause was nutritional. A similar epidemic was recently described in Tanzania. A number of infectious neuropathies and myopathies are reviewed, including leprosy, tuberculosis, hemorrhagic fevers (Ebola and Marburg filoviruses, Lassa, Argentinean and Bolivian arenaviruses), the human retrovirus human T-cell lymphotropic virus type I, Lyme disease and postimmunization neuropathies. The tropics continue to contribute interesting and important clinical conditions that may illuminate the etiopathiogenesis of other common disorders. PMID:9848004

Román, G

1998-10-01

167

Tropical Cyclone Report  

NSDL National Science Digital Library

This detailed description of Hurricane Isabel, a long-lived Cape Verde hurricane that reached Category 5 status on the Saffir-Simpson Hurricane Scale, contains a synoptic history, meteorological statistics, casualty and damage statistics, and a forecast and warning critique. The storm made landfall near Drum Inlet on the Outer Banks of North Carolina as a category 2 hurricane and is considered to be one of the most significant tropical cyclones to affect portions of northeastern North Carolina and east-central Virginia since Hurricane Hazel in 1954 and the Chesapeake-Potomac Hurricane of 1933. Voluminous charts include best track, selected ship reports, selected surface observations, and rainfall. A warnings chart is also included along with a best track map.

2007-12-12

168

Tropical Ice Cores Measure Climate  

NSDL National Science Digital Library

This video profiles glaciologist Lonnie Thompson and his research into tropical mountain glaciers as a way to understand climate history. Beginning in the 1970s, Thompson recognized that tropical ice cores contain information relating to tropical climate phenomena, including El Niño events and monsoons. These phenomena are not archived in ice from polar regions. Thompson explains that his archive of ice cores is full of clues that, taken together with records collected from around the world, can help scientists create a timeline that tells Earth's climate story.

Sciencenow, Nova; Domain, Teachers'

169

Role of the Rodent Acrosome and Perforatorium in Fertilization  

Microsoft Academic Search

A study has been made of the morphology of spermatozoa recovered from the female genital tract shortly after coitus, including spermatozoa entering and within eggs, in five rodent species. Elevation and loss of the acrosome was observed to occur in actively motile golden-hamster spermatozoa found in the cumulus oophorus and tubal fluid. Motile spermatozoa lacking the acrosome were also seen

C. R. Austin; M. W. H. Bishop

1958-01-01

170

PERFLUOROOCTANE SULFONATE (PFOS) DISRUPTS THE THYROID STATUS IN LABORATORY RODENTS  

EPA Science Inventory

PERFLUOROOCTANE SULFONATE (PFOS) DISRUPTS THE THYROID STATUS IN LABORATORY RODENTS. C. Lau, J.R. Thibodeaux, R.G. Hanson, B.E. Gray and J.M. Rogers. Reprod. Tox. Div. NHEERL, US EPA, Research Triangle Park, NC. PFOS is an environmental contaminant ubiquitously found in h...

171

What does the oxygen isotope composition of rodent teeth record?  

NASA Astrophysics Data System (ADS)

Oxygen isotope compositions of tooth phosphate (?18Op) were measured in 107 samples defined on the basis of teeth obtained from 375 specimens of extant rodents. These rodents were sampled from pellets collected in Europe from 38°N (Portugal) to 65°N (Finland) with most samples coming from sites located in France and Spain. Large oxygen isotopic variability in ?18Op is observed both at the intra- and inter-species scale within pellets from a given location. This isotopic variability is partly explained by heterochrony in tooth formation related to the short time of mineralization for all rodent species as well as the duration of mineralization that is species-dependent. Consequently, tooth phosphate of rodents records a short seasonal interval in the oxygen isotope compositions of meteoric waters (?18Omw). In addition, inter-species isotopic variability observed in the same pellets suggests behavioural differences implying distinct isotopic compositions for species living in the same location. At the scale of Europe, a robust linear oxygen isotope fractionation equation was determined for Muroidea between the midrange ?18Op values and ?18Omw values: ?18Op=1.21(±0.20)?18Omw+24.76(±2.70) with R2=0.79 (n=9; p<0.0001).

Royer, Aurélien; Lécuyer, Christophe; Montuire, Sophie; Amiot, Romain; Legendre, Serge; Cuenca-Bescós, Gloria; Jeannet, Marcel; Martineau, François

2013-01-01

172

Juquitiba-like Hantavirus from 2 Nonrelated Rodent Species, Uruguay  

PubMed Central

Serologic and genetic analyses indicate that a Juquitiba-like hantavirus circulates in Maldonado, Uruguay. This virus is carried by 2 rodent species, Oligoryzomys nigripes and Oxymycterus nasutus. The same hantavirus in 2 nonrelated species can be explained by a spillover infection or a host-switching event.

Delfraro, Adriana; Tome, Lorena; D'Elia, Guillermo; Clara, Mario; Achaval, Federico; Russi, Jose C.

2008-01-01

173

Recent and Widespread Rapid Morphological Change in Rodents  

PubMed Central

In general, rapid morphological change in mammals has been infrequently documented. Examples that do exist are almost exclusively of rodents on islands. Such changes are usually attributed to selective release or founder events related to restricted gene flow in island settings. Here we document rapid morphological changes in rodents in 20 of 28 museum series collected on four continents, including 15 of 23 mainland sites. Approximately 17,000 measurements were taken of 1302 rodents. Trends included both increases and decreases in the 15 morphological traits measured, but slightly more trends were towards larger size. Generalized linear models indicated that changes in several of the individual morphological traits were associated with changes in human population density, current temperature gradients, and/or trends in temperature and precipitation. When we restricted these analyses to samples taken in the US (where data on human population trends were presumed to be more accurate), we found changes in two additional traits to be positively correlated with changes in human population density. Principle component analysis revealed general trends in cranial and external size, but these general trends were uncorrelated with climate or human population density. Our results indicate that over the last 100+ years, rapid morphological change in rodents has occurred quite frequently, and that these changes have taken place on the mainland as well as on islands. Our results also suggest that these changes may be driven, at least in part, by human population growth and climate change.

Pergams, Oliver R. W.; Lawler, Joshua J.

2009-01-01

174

Interspecific competition in small rodents: from populations to individuals  

Microsoft Academic Search

The role of interspecific competition in shaping animal and plant communities has formed one of the major issues in ecology for decades. Small mammals, mainly rodents, have been among the model systems used for research on interspecific competition. Most studies within small mammal systems in the past have examined effects of competition on population attributes such as on population size,

Jana A. Eccard; Hannu Ylönen

2003-01-01

175

Leptospira spp. in Rodents and Shrews in Germany.  

PubMed

Leptospirosis is an acute, febrile disease occurring in humans and animals worldwide. Leptospira spp. are usually transmitted through direct or indirect contact with the urine of infected reservoir animals. Among wildlife species, rodents act as the most important reservoir for both human and animal infection. To gain a better understanding of the occurrence and distribution of pathogenic leptospires in rodent and shrew populations in Germany, kidney specimens of 2973 animals from 11 of the 16 federal states were examined by PCR. Rodent species captured included five murine species (family Muridae), six vole species (family Cricetidae) and six shrew species (family Soricidae). The most abundantly trapped animals were representatives of the rodent species Apodemus flavicollis, Clethrionomys glareolus and Microtus agrestis. Leptospiral DNA was amplified in 10% of all animals originating from eight of the 11 federal states. The highest carrier rate was found in Microtus spp. (13%), followed by Apodemus spp. (11%) and Clethrionomys spp. (6%). The most common Leptospira genomospecies determined by duplex PCR was L. kirschneri, followed by L. interrogans and L. borgpetersenii; all identified by single locus sequence typing (SLST). Representatives of the shrew species were also carriers of Leptospira spp. In 20% of Crocidura spp. and 6% of the Sorex spp. leptospiral DNA was detected. Here, only the pathogenic genomospecies L. kirschneri was identified. PMID:25062275

Mayer-Scholl, Anne; Hammerl, Jens Andre; Schmidt, Sabrina; Ulrich, Rainer G; Pfeffer, Martin; Woll, Dietlinde; Scholz, Holger C; Thomas, Astrid; Nöckler, Karsten

2014-01-01

176

Segmenting Rodent Cardiac Ultrasound Images Using Direct Posterior Models  

Microsoft Academic Search

Lack of an accurate generative model makes it hard to use classical MAP segmentation algorithms to jointly segment the epi- and the endocardium in ultrasound rodent cardiac images. This paper proposes an alternate methodology for such segmentation. The methodology directly models the posterior probability of segmentation using penalized logistic models. A level-set segmentation algorithm is developed using direct posterior models.

Yong Yue; Hemant D. Tagare

2009-01-01

177

Comparative metabolism of furan in rodent and human cryopreserved hepatocytes.  

PubMed

Furan is a liver toxicant and carcinogen in rodents. Although humans are most likely exposed to furan through a variety of sources, the effect of furan exposure on human health is still unknown. In rodents, furan requires metabolism to exert its toxic effects. The initial product of the cytochrome P450 2E1-catalyzed oxidation is a reactive ?,?-unsaturated dialdehyde, cis-2-butene-1,4-dial (BDA). BDA is toxic and mutagenic and consequently is considered responsible for the toxic effects of furan. The urinary metabolites of furan in rats are derived from the reaction of BDA with cellular nucleophiles, and precursors to these metabolites are detected in furan-exposed hepatocytes. Many of these precursors are 2-(S-glutathionyl)butanedial-amine cross-links in which the amines are amino acids and polyamines. Because these metabolites are derived from the reaction of BDA with cellular nucleophiles, their levels are a measure of the internal dose of this reactive metabolite. To compare the ability of human hepatocytes to convert furan to the same metabolites as rodent hepatocytes, furan was incubated with cryopreserved human and rodent hepatocytes. A semiquantitative liquid chromatography with tandem mass spectrometry assay was developed for a number of the previously characterized furan metabolites. Qualitative and semiquantitative analysis of the metabolites demonstrated that furan is metabolized in a similar manner in all three species. These results indicate that humans may be susceptible to the toxic effects of furan. PMID:24751574

Gates, Leah A; Phillips, Martin B; Matter, Brock A; Peterson, Lisa A

2014-07-01

178

Juquitiba-like hantavirus from 2 nonrelated rodent species, Uruguay.  

PubMed

Serologic and genetic analyses indicate that a Juquitiba-like hantavirus circulates in Maldonado, Uruguay. This virus is carried by 2 rodent species, Oligoryzomys nigripes and Oxymycterus nasutus. The same hantavirus in 2 nonrelated species can be explained by a spillover infection or a host-switching event. PMID:18760017

Delfraro, Adriana; Tomé, Lorena; D'Elía, Guillermo; Clara, Mario; Achával, Federico; Russi, José C; Arbiza Rodonz, Juan R

2008-09-01

179

The Evolution of Optical Signals in Human and Rodent Cortex  

Microsoft Academic Search

The time course of optical intrinsic signals was examined in order to characterize the evolution of response in human and rodent cortex. Both subtraction\\/ratio and principal component analyses were used to construct time-course curves. The time course began at a prestimulus baseline, responded with a finite delay, overcompensated, reduced to a maintenance level, and then disappeared. The magnitude, spatial involvement,

Andrew F. Cannestra; Anne J. Blood; Keith L. Black; Arthur W. Toga

1996-01-01

180

Unexpected primitive rodents in the Quaternary of Argentina  

Microsoft Academic Search

This article describes the first fossils recorded in the Hernandarias Formation (Pleistocene) in Entre Ríos province (eastern Argentina). They are represented by three teeth assigned to the caviomorph rodents (Rodentia, Mammalia) Aenigmys diamantensis gen. et sp. nov. and Eumysops. To establish the phylogenetic affinities of the two most enigmatic teeth, their enamel microstructure was studied. Aenigmys diamantensis is considered the

María G. Vucetich; Emma C. Vieytes; Diego H. Verzi; Jorge I. Noriega; Eduardo P. Tonni

2005-01-01

181

The role of phylogeny in desert rodent community assembly.  

PubMed

Recent advances in molecular genetics and phylogenetic reconstruction have the potential to transform ecology by providing new insights into the historical evolution of ecological communities. This study by Stevens and collaborators complements decades of previous research on desert rodents, by combining data from a field study and a phylogenetic tree for Mojave Desert rodents to address patterns and processes of community assembly. The number of coexisting rodent species is positively correlated, and the average phylogenetic distance among these species is negatively correlated with perennial plant species richness. As rodent species diversity increases along a gradient of increasing environmental heterogeneity, communities are composed of increasingly related species: there is a consistent pattern of phylogenetic structure from over-dispersed through random to clumped. I discuss this pattern in the light of complementary results of previous studies. This paper is noteworthy for calling attention to still unanswered questions about how the historical events of speciation, colonization, extinction, and trait evolution and their relationship to past climates and vegetation have given rise to current patterns of community organization. PMID:22324970

Brown, James H

2012-03-01

182

Andes hantavirus variant in rodents, southern Amazon Basin, Peru.  

PubMed

We investigated hantaviruses in rodents in the southern Amazon Basin of Peru and identified an Andes virus variant from Neacomys spinosus mice. This finding extends the known range of this virus in South America and the range of recognized hantaviruses in Peru. Further studies of the epizoology of hantaviruses in this region are warranted. PMID:24447689

Razuri, Hugo; Tokarz, Rafal; Ghersi, Bruno M; Salmon-Mulanovich, Gabriela; Guezala, M Claudia; Albujar, Christian; Mendoza, A Patricia; Tinoco, Yeny O; Cruz, Christopher; Silva, Maria; Vasquez, Alicia; Pacheco, Víctor; Ströher, Ute; Guerrero, Lisa Wiggleton; Cannon, Deborah; Nichol, Stuart T; Hirschberg, David L; Lipkin, W Ian; Bausch, Daniel G; Montgomery, Joel M

2014-02-01

183

Rodent Models of Alcoholic Liver Disease: Of Mice and Men  

PubMed Central

Alcoholic liver disease (ALD) is a major cause of acute and chronic liver disease worldwide. The progressive nature of ALD is well described however the complex interactions under which these pathologies evolve remain to be fully elucidated. Clinically there are no clear biomarkers or universally accepted, effective treatment strategies for ALD. Experimental models of ALD are an important component in identifying underlying mechanisms of alcohol-induced injury to develop better diagnostic markers, predictors of disease progression, and therapeutic targets to manage, halt, or reverse disease progression. Rodents remain the most accessible model for studying ALD pathology. Effective rodent models must mimic the natural history of ALD while allowing examination of complex interactions between multiple hepatic, and non-hepatic, cell types in the setting of altered metabolic or oxidative/nitrosative stress, inflammatory responses, and sensitivity to cytotoxic stress. Additionally, mode and duration of alcohol delivery influences hepatic response and presents unique challenges in understanding disease pathology. This review provides an overview of rodent models of ALD, their strengths and weaknesses relative to human disease states, and provides insight of the potential to develop novel rodent models to simulate the course of human ALD.

Brandon-Warner, Elizabeth; Schrum, Laura W.; Schmidt, C. Max; McKillop, Iain H.

2012-01-01

184

Residential indoor humidity control in tropics and sub-tropics  

Microsoft Academic Search

The use of direct expansion (DX) air conditioning (A\\/C) systems is widely seen in residential buildings in tropics and sub-tropics. However, most DX A\\/C systems are equipped with single-speed compressor and supply fan, relying on On—Off cycling as a low-cost approach to maintain only indoor dry-bulb temperature, whereas the indoor air humidity is not controlled directly. This also leads to

MY Chan; SM Deng; XG Xu

2009-01-01

185

Experiments on seed predation by rodents and ants in the Israeli desert  

Microsoft Academic Search

Utilization of non-native seeds by seed-eating rodents and ants was studied experimentally in the field. It was found that patterns of granivory in the Israeli deserts are very similar to those reported for the same groups in the deserts of North America. Rodents are more efficient than ants at finding and harvesting seeds. Only rodents can find and harvest seeds

Zvika Abramsky

1983-01-01

186

The Touchscreen Cognitive Testing Method for Rodents: How to Get the Best out of Your Rat  

ERIC Educational Resources Information Center

The touchscreen testing method for rodents is a computer-automated behavioral testing method that allows computer graphic stimuli to be presented to rodents and the rodents to respond to the computer screen via a nose-poke directly to the stimulus. The advantages of this method are numerous; however, a systematic study of the parameters that…

Bussey, Timothy J.; Padain, Tina L.; Skillings, Elizabeth A.; Winters, Boyer D.; Morton, A. Jennifer; Saksida, Lisa M.

2008-01-01

187

Evidence for Higher Rates of Nucleotide Substitution in Rodents Than in Man  

Microsoft Academic Search

When the coding regions of 11 genes from rodents (mouse or rat) and man are compared with those from another mammalian species (usually bovine), it is found that rodents evolve significantly faster than man. The ratio of the number of nucleotide substitutions in the rodent lineage to that in the human lineage since their divergence is 2.0 for synonymous substitutions

Chung-I. Wu; Wen-Hsiung Li

1985-01-01

188

The spatio-temporal distribution of a rodent reservoir host of cutaneous leishmaniasis  

Microsoft Academic Search

Summary 1. The rodent Psammomys obesus is the main reservoir host for Leishmania major, the causative agent of cutaneous leishmaniasis in Tunisia, much of North Africa and mid-western Asia. An understanding of the population dynamics of this rodent is essential to establish a preventive control strategy based on the early prediction of rodent outbreaks. 2. The study of P. obesus

E. Fichet-Calvet; I. Jomaa; B. Zaafouri; R. W. Ashford; R. Ben-Ismail; P. DELATTREx

2000-01-01

189

Segmentation of Rodent Whole-Body Dynamic PET Images: An Unsupervised Method Based on Voxel Dynamics  

Microsoft Academic Search

Positron emission tomography (PET) is a useful tool for pharmacokinetics studies in rodents during the preclinical phase of drug and tracer development. However, rodent organs are small as compared to the scanner's intrinsic resolution and are affected by physiological movements. We present a new method for the segmentation of rodent whole-body PET images that takes these two difficulties into account

Renaud Maroy; Raphaël Boisgard; Claude Comtat; Vincent Frouin; Pascal Cathier; Edouard Duchesnay; Freédéric Dolle; Peter E. Nielsen; Régine Trébossen; Bertrand Tavitian

2008-01-01

190

Serologic Survey of Oklahoma Rodents: Evidence for the Presence of a Hantavirus and an Arenavirus  

Microsoft Academic Search

We conducted a statewide survey of Oklahoma small mammals to test for antibod- ies against rodent-borne viral diseases. Four rodent species had antibody to Sin Nombre virus (SNV), the primary causative agent of hantavirus pulmonary syn- drome (HPS), and two species had antibody to Whitewater Arroyo virus, an arenavirus associated with human fatalities. The rodent reservoirs for other HPS- causing

Richard A. Nisbett; Michael D. Stuart; Gloria M. Caddell; Charles H. Calisher

2001-01-01

191

Bartonella species in invasive rats and indigenous rodents from Uganda.  

PubMed

The presence of bartonellae in invasive rats (Rattus rattus) and indigenous rodents (Arvicanthis niloticus and Cricetomys gambianus) from two districts in Uganda, Arua and Zombo, was examined by PCR detection and culture. Blood from a total of 228 R. rattus, 31 A. niloticus, and 5 C. gambianus was screened using genus-specific primers targeting the 16S-23S intergenic spacer region. Furthermore, rodent blood was plated on brain heart infusion blood agar, and isolates were verified as Bartonella species using citrate synthase gene- (gltA) specific primers. One hundred and four fleas recovered from R. rattus were also tested for the presence of Bartonella species using the same gltA primer set. An overall prevalence of 1.3% (three of 228) was obtained in R. rattus, whereas 61.3% of 31 A. niloticus and 60% of five C. gambianus were positive for the presence of Bartonella species. Genotypes related to Bartonella elizabethae, a known zoonotic pathogen, were detected in three R. rattus and one C. gambianus. Bartonella strains, similar to bacteria detected in indigenous rodents from other African countries, were isolated from the blood of A. niloticus. Bartonellae, similar to bacteria initially cultured from Ornithodorus sonrai (soft tick) from Senegal, were found in two C. gambianus. Interestingly, bartonellae detected in fleas from invasive rats were similar to bacteria identified in indigenous rodents and not their rat hosts, with an overall prevalence of 6.7%. These results suggest that if fleas are competent vectors of these bartonellae, humans residing in these two districts of Uganda are potentially at greater risk for exposure to Bartonella species from native rodents than from invasive rats. The low prevalence of bartonellae in R. rattus was quite surprising, in contrast, to the detection of these organisms in a large percentage of Rattus species from other geographical areas. A possible reason for this disparity is discussed. PMID:24575846

Billeter, Sarah A; Borchert, Jeff N; Atiku, Linda A; Mpanga, Joseph T; Gage, Kenneth L; Kosoy, Michael Y

2014-03-01

192

Nutritional Evaluation of NASA's Rodent Food Bar Diet  

NASA Technical Reports Server (NTRS)

Tests are being conducted on NASA's rodent Food Bar in preparation for long-term use as the rat and mouse diet aboard the International Space Station. Nutritional analyses are performed after the bars are manufactured and then repeated periodically to determine nutritional stability. The primary factors analyzed are protein, ash, fat, fiber, moisture, amino acids, fatty acids, and minerals. Nutrient levels are compared to values published in the National Research Council's dietary requirements for rodents, and also to those contained in several commonly used commercial rodent lab diets. The Food Bar is manufactured from a powdered diet to which moisture is added as it is processed through an extruder. The bars are dipped into potassium sorbate, vacuum-sealed, and irradiated. In order to determine nutrient changes during extrusion and irradiation, the powdered diet, the non-irradiated bars, and the irradiated bars are all analyzed. We have observed lower values for some nutrients (iodine, vitamin K, and iron) in the Food Bars compared with NRC requirements. Many nutrients in the Food Bars are contained at a higher level than levels in the NRC requirements. An additional factor we are investigating is the 26% moisture level in the Food Bars, which drops to about 15% within a week, compared to a stable 10% moisture in many standard lab chow diets. In addition to the nutritional analyses, the food bar is being fed to several strains of rats and mice, and feeding study and necropsy results are being observed (Barrett et al, unpublished data). Information from the nutritional analyses and from the rodent studies will enable us to recommend the formulation that will most adequately meet the rodent Food Bar requirements for long-term use aboard the Space Station.

Barrett, Joyce E.; Yu, Diane S.; Dalton, Bonnie P.

2000-01-01

193

Tropical Ecosystems and Ecological Concepts  

NASA Astrophysics Data System (ADS)

Over one third of the earth's terrestrial surface is situated in the tropics, with environments ranging from hot deserts to tropical rain forests. This introductory textbook, aimed at students studying tropical ecology, provides a comprehensive guide to the major tropical biomes and is unique in its balanced coverage of both aquatic and terrestrial systems. The volume considers the human ecological dimension, covering issues such as population growth, urbanization, agriculture and fisheries, natural resource use, and pollution. It is international in scope and addresses global issues such as conservation of biodiversity, climate change, and the concept of ecological sustainability. The text is supported throughout by boxes containing supplementary material on a range of topics and organisms, mathematical concepts and calculations, and is enlivened with clear line diagrams, maps, and photographs. A cross-referenced glossary, extensive bibliography, and comprehensive index are included as further aids to study.

Osborne, Patrick L.

2000-09-01

194

Cloudsat Dissects Tropical Storm Ileana  

NASA Video Gallery

NASA's CloudSat satellite's Cloud Profiling Radar captured a sideways look across Tropical Storm Ileana on Aug. 27 at 20:40 UTC. The colors indicate intensity of reflected radar energy. The blue ar...

195

Tropical Storm Lee to Newfoundland  

NASA Video Gallery

This video shows Tropical Storm Lee as it made landfall in Louisiana and Mississippi on September 4, 2011. This storm produced flooding and tornadoes to the southern states all the way to flooding ...

196

Hydrology of a Tropical Peatland  

NASA Astrophysics Data System (ADS)

The hydrology of tropical peat forests is tied closely to decomposition processes in the soil and thus to the role of these forests as sinks of atmospheric carbon. We present results from an ongoing study on the hydrology and carbon cycle of a tropical peat forest in Brunei Darussalam. Data from rain gauges and well piezometers are combined with meteorological data for a preliminary hydrological balance.

Cobb, A.; Gandois, L.; Abu Salim, K.; Harvey, C. F.

2011-12-01

197

Tropical Cyclone Gonu  

NASA Technical Reports Server (NTRS)

You might expect to see a storm with near-perfect symmetry and a well-defined eye hovering over the warm waters of the Caribbean or in the South Pacific, but Tropical Cyclone Gonu showed up in an unusual place. On June 4, 2007, when the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Aqua satellite captured this image, Tropical Cyclone Gonu was approaching the northeastern shore of Oman, a region better known for hot desert conditions. Though rare, cyclones like Gonu are not unheard of in the northern Indian Ocean basin. Most cyclones that form in the region form over the Bay of Bengal, east of India. Those that take shape over the Arabian Sea, west of the Indian peninsula, tend to be small and fizzle out before coming ashore. Cyclone Gonu is a rare exception. As of June 4, 2007, the powerful storm had reached a dangerous Category Four status, and it was forecast to graze Oman's northeastern shore, following the Gulf of Oman. According to storm statistics maintained on Unisys Weather, the last storm of this size to form over the Arabian Sea was Cyclone 01A, which tracked northwest along the coast of India between May 21 and May 28, 2001. Unlike Gonu's forecasted track, Cyclone 01A never came ashore. MODIS acquired this photo-like image at 12:00 p.m. local time (9:00 UTC), a few hours after the Joint Typhoon Warning Center estimated Gonu's sustained winds to be over 240 kilometers per hour (145 miles per hour). The satellite image confirms that Gonu was a super-powerful cyclone. The storm has the hallmark tightly wound arms that spiral around a well-defined, circular eye. The eye is surrounded by a clear wall of towering clouds that cast shadows on the surrounding clouds. Called hot towers, these clouds are a sign of the powerful uplift that feeds the storm. The symmetrical spirals, clear eye, and towering clouds are all features regularly seen in satellite images of other particularly powerful cyclones, which are also known as typhoons or hurricanes when they form in other parts of the world. The high-resolution image provided above is at MODIS' full spatial resolution (level of detail) of 250 meters per pixel. The MODIS Rapid Response System provides this image at additional resolutions.

2007-01-01

198

[Strategies for sustainable management of commensal rodents : Definitions of control objectives at communal level].  

PubMed

The German Act on the Prevention and Control of Infectious Diseases in Man (Infektionsschutzgesetz, IfSG) provides a legal framework for activities and responsibilities concerning communal rodent control. However, actual governance of communal rodent control is relatively heterogeneous, as federal states (Bundesländer) have different or even no regulations for prevention and management of commensal rodent infestations (e.g. brown rats, roof rats and house mice). Control targets and control requirements are rarely precisely defined and often do not go beyond general measures and objectives. Although relevant regulations provide information about agreed preventive measures against rodents, the concept of sustainability is not expressed as such. A centrally managed database-supported municipal rodent control is a key factor for sustainability because it allows a systematic and analytical approach to identify and reduce rodent populations. The definition of control objectives and their establishment in legal decrees is mandatory for the implementation of a sustainable management strategy of rodent populations at a local level. Systematic recording of rodent infestations through municipal-operated monitoring provides the essential data foundation for a targeted rodent management which is already implemented in some German and European cities and nationwide in Denmark. A sustainable rodent management includes a more targeted rodenticide application which in the long-term will lead to an overall reduction of rodenticide use. Thus, the benefits of sustainable rodent management will be a reduction of rodenticide exposure to the environment, prevention of resistance and long-term economical savings. PMID:24781906

Plenge-Bönig, A; Schmolz, E

2014-05-01

199

Tropical Cyclone Indlala  

NASA Technical Reports Server (NTRS)

On March 14, 2007, storm-weary Madagascar braced for its fourth land-falling tropical cyclone in as many months. Cyclone Indlala was hovering off the island's northeast coast when the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Aqua satellite captured this photo-like image at 1:40 p.m. local time (10:40 UTC). Just over a hundred kilometers offshore, the partially cloudy eye at the heart of the storm seems like a vast drain sucking in a disk of swirling clouds. According to reports from the Joint Typhoon Warning Center issued less than three hours after MODIS captured this image, Indlala had winds of 115 knots (132 miles per hour), with gusts up to 140 knots (161 mph). Wave heights were estimated to be 36 feet. At the time of the report, the storm was predicted to intensify through the subsequent 12-hour period, to turn slightly southwest, and to strike eastern Madagascar as a Category 4 storm with sustained winds up to 125 knots (144 mph), and gusts up to 150 knots (173 mph). According to Reuters AlertNet news service, Madagascar's emergency response resources were taxed to their limit in early March 2007 as a result of extensive flooding in the North, drought and food shortages in the South, and three previous hits from cyclones in the preceding few months: Bondo in December 2006, Clovis in January 2007, and Gamede in February.

2007-01-01

200

Mesostigmatid mite infestations of rodents in diverse biotopes of central and southern India.  

PubMed

Examination of 165 rodents trapped in domestic, peridomestic, and feral biotopes of central and southern India revealed the presence of 1,359 mesostigmatid mites. Rodents in central India were infested with 1 species of mite, Laelaps nuttalli; 98% of these mites were recovered from the peridomestic rodent Bandicota bengalensis. Material from the burrow nest of a peridomestic rodent examined in central India revealed the mite, Hypoaspis miles. Rodents from the diverse biotopes of southern India were infested by 8 species of mites: L. nuttalli, Laelaps buxtoni, Laelaps myonyssognathus, Androlaelaps aduncus, Androlaelaps marshalli, Androlaelaps sp. A, Hypoaspis sp. 1, and Hypoaspis sp. 2. Sheep from nearby villages regularly graze in feral biotopes. From the hair of these sheep, 2 species of mesostigmatid mites were recovered, A. aduncus and A. marshalli. The sheep appeared to aid the dispersal of rodent-infesting mites passively. Laelaps nuttalli was the predominant mite species found on the peridomestic rodent B. bengalensis. In both central and southern India, the prevalence, mean intensity, and relative density of this mite were much higher on peridomestic rodents than on domestic and feral rodents. A significant negative correlation was found between the numbers of mites and fleas infesting rodents in central India. A highly significant positive association between A. marshalli and A. aduncus on the feral rodent Tatera indica was recorded. In southern India, the overall prevalence of the 8 species of mites was highest on Mus platythrix. However, the combined prevalence of these mites on 2 feral rodents T. indica and M. platythrix was lower than their prevalence on B. bengalensis. Similarly, the combined values for mean intensity and relative density of these mites on the 2 feral rodents were lower than on the peridomestic rodent B. bengalensis. PMID:10207385

Saxena, V K

1999-02-01

201

Limitations to adaptive optics image quality in rodent eyes  

PubMed Central

Adaptive optics (AO) retinal image quality of rodent eyes is inferior to that of human eyes, despite the promise of greater numerical aperture. This paradox challenges several assumptions commonly made in AO imaging, assumptions which may be invalidated by the very high power and dioptric thickness of the rodent retina. We used optical modeling to compare the performance of rat and human eyes under conditions that tested the validity of these assumptions. Results showed that AO image quality in the human eye is robust to positioning errors of the AO corrector and to differences in imaging depth and wavelength compared to the wavefront beacon. In contrast, image quality in the rat eye declines sharply with each of these manipulations, especially when imaging off-axis. However, some latitude does exist to offset these manipulations against each other to produce good image quality.

Zhou, Xiaolin; Bedggood, Phillip; Metha, Andrew

2012-01-01

202

Hantavirus Infection in Humans and Rodents, Northwestern Argentina  

PubMed Central

We initiated a study to elucidate the ecology and epidemiology of hantavirus infections in northern Argentina. The northwestern hantavirus pulmonary syndrome (HPS)–endemic area of Argentina comprises Salta and Jujuy Provinces. Between 1997 and 2000, 30 HPS cases were diagnosed in Jujuy Province (population 512,329). Most patients had a mild clinical course, and the death rate (13.3%) was low. We performed a serologic and epidemiologic survey in residents of the area, in conjunction with a serologic study in rodents. The prevalence of hantavirus antibodies in the general human population was 6.5%, one of the highest reported in the literature. No evidence of interhuman transmission was found, and the high prevalence of hantavirus antibody seemed to be associated with the high infestation of rodents detected in domestic and peridomestic habitats.

Levis, Silvana; Calderon, Gladys; Ramirez, Josefina; Bravo, Daniel; Lozano, Elena; Ripoll, Carlos; St. Jeor, Stephen; Ksiazek, Thomas G.; Barquez, Ruben M.; Enria, Delia

2003-01-01

203

Pet Rodents and Fatal Lymphocytic Choriomeningitis in Transplant Patients  

PubMed Central

In April 2005, 4 transplant recipients became ill after receiving organs infected with lymphocytic choriomeningitis virus (LCMV); 3 subsequently died. All organs came from a donor who had been exposed to a hamster infected with LCMV. The hamster was traced back through a Rhode Island pet store to a distribution center in Ohio, and more LCMV-infected hamsters were discovered in both. Rodents from the Ohio facility and its parent facility in Arkansas were tested for the same LCMV strain as the 1 involved in the transplant-associated deaths. Phylogenetic analysis of virus sequences linked the rodents from the Ohio facility to the Rhode Island pet store, the index hamster, and the transplant recipients. This report details the animal traceback and the supporting laboratory investigations.

Pavlin, Boris I.; Albarino, Cesar G.; Comer, James A.; Erickson, Bobbie R.; Oliver, Jennifer B.; Sealy, Tara K.; Vincent, Martin J.; Nichol, Stuart T.; Paddock, Christopher D.; Tumpey, Abbigail J.; Wagoner, Kent D.; Glauer, R. David; Smith, Kathleen A.; Winpisinger, Kim A.; Parsely, Melody S.; Wyrick, Phil; Hannafin, Christopher H.; Bandy, Utpala; Zaki, Sherif; Rollin, Pierre E.; Ksiazek, Thomas G.

2007-01-01

204

Experimental infections by Brucella suis type 4 in Alaskan rodents.  

PubMed

The susceptibility of nine species of rodents and one species of lagomorph to Brucella suis type 4 was studied experimentally. The rodent species included: guinea pig (Cavia porcellus), Scandinavian lemming (Lemmus lemmus), brown lemming (L. sibiricus), northern red-backed vole (Clethrionomys rutilis), varying lemmings (Dicrostonyx stevensoni and D. rubricatus), yellow-cheeked vole (Microtus xanthognathus), flying squirrel (Glaucomys sabrinus) and ground squirrel (Citellus parryii). The lagomorph, Lepus americanus (varying hare), was also studied. All of these species were readily infected by intraperitoneal inoculations of brucellae. Pathologic responses were not marked in most of these species. However, both species of varying lemmings responded dramatically to infections initiated by about as few as two cfu. All individuals of both species that were not killed eventually died from the infection. PMID:7463596

Miller, L G; Neiland, K A

1980-10-01

205

Limitations to adaptive optics image quality in rodent eyes.  

PubMed

Adaptive optics (AO) retinal image quality of rodent eyes is inferior to that of human eyes, despite the promise of greater numerical aperture. This paradox challenges several assumptions commonly made in AO imaging, assumptions which may be invalidated by the very high power and dioptric thickness of the rodent retina. We used optical modeling to compare the performance of rat and human eyes under conditions that tested the validity of these assumptions. Results showed that AO image quality in the human eye is robust to positioning errors of the AO corrector and to differences in imaging depth and wavelength compared to the wavefront beacon. In contrast, image quality in the rat eye declines sharply with each of these manipulations, especially when imaging off-axis. However, some latitude does exist to offset these manipulations against each other to produce good image quality. PMID:22876346

Zhou, Xiaolin; Bedggood, Phillip; Metha, Andrew

2012-08-01

206

A Functional analysis of circadian pacemakers in nocturnal rodents  

Microsoft Academic Search

Summary 1Phase response curves for 15' bright light pulses of four species of nocturnal rodents are described. All show delay phase shifts early in the subjective night, advance shifts in the late subjective night, and relative insensitivity during the subjective day.2The broad scatter in measured phase-shifts is largely due to error of measurement: the response of the pacemakers to light

Serge Daan; Colin S. Pittendrigh

1976-01-01

207

A functional analysis of circadian pacemakers in nocturnal rodents  

Microsoft Academic Search

Summary 1.The circadian pacemakers controlling activity rhythms in four species of rodents are compared, as freerunning systems in constant darkness. In analyzing their stability the distinction is made between (1) spontaneous day-to-day instability of frequency, and (2) a longer-term lability, some of which is traceable to identified causes.2.Serial correlation analysis indicates that the precision (day-to-day stability) of the pacemaker's period

Colin S. Pittendrigh; Serge Daan

1976-01-01

208

A functional analysis of circadian pacemakers in nocturnal rodents  

Microsoft Academic Search

Summary 1.In a preceding paper (Pittendrigh and Daan, 1976a) differences in the lability of the freerunning circadian period (t) in constant darkness (DD) were described among four species of rodents. This lability (i) is strongly correlated with the responses of t to (ii) D2O-administration and to (iii) constant light (LL) of various intensities. The question is raised whether these are

Serge Daan; Colin S. Pittendrigh

1976-01-01

209

Do biodiversity hotspots match with rodent conservation hotspots?  

Microsoft Academic Search

Biodiversity hotspots are used widely to designate priority regions for conservation efforts. It is unknown, however, whether\\u000a the current network of hotspots adequately represents globally threatened taxonomic diversity for whole plant and animal groups.\\u000a We used a mammalian group traditionally neglected in terms of conservation efforts, the rodents, in order to test whether\\u000a biodiversity hotspots match the current distribution of

Giovanni Amori; Spartaco Gippoliti; Luca Luiselli

210

Pharmacological study of Stachytarpheta cayennensis Vahl in rodents  

Microsoft Academic Search

Freeze-dried aqueous extracts (AEs, 0.1–1g\\/kg body wt., p.o.) obtained from entire or selected parts of Stachytarpheta cayennensis were tested for their effects on gastric secretion, gastric motility, inflammation and pain in rodents, with the purpose of validating the plant's ethnomedical uses. The AE-Total, AE-Flowers and AE-Leaves but not AE-Stems inhibited the gastric acid secretion in pylorus-ligated rats with varying potency.

S. Mesia-Vela; C. Souccar; M. T. R. Lima-Landman; A. J. Lapa

2004-01-01

211

Beyond the rodent model: Calorie restriction in rhesus monkeys  

Microsoft Academic Search

Lifespan extension and reduction of age-related disease by calorie restriction (CR) are among the most consistent findings\\u000a in gerontological research. The well known effects of CR have been demonstrated many times in rodents and other short-lived\\u000a species. However, effects of CR on aging in longer-lived species, more closely related to humans, were unknown until recently.\\u000a Studies of CR and aging

Donald K. Ingram; George S. Roth

1997-01-01

212

Mating strategies of a nocturnal, desert rodent ( Dipodomys spectabilis )  

Microsoft Academic Search

Summary The mating system of a nocturnal, desert rodent, the banner-tailed kangaroo rat (Dipodomys spectabilis) was studied through direct observation, live-trapping, and radiotelemetry over a 13-month period from August 1986 to August 1987. Mating behavior varied from exclusive matings between male and female neighbors to competitive mate searching and direct male competition. In summer matings and early in a November

Jan A. Randall

1991-01-01

213

Fossil Occurrence of Murine Rodent (Nesokia indica) in the Sudan.  

PubMed

A specimen of the murid rodent Nesokia indica has been recovered from a late Paleolithic archeological site in the Sudan. This is a range 1200 km south of the site of any known occurrences, and it indicates a different environment near the Nile River than that which exists at the present time. The late Paleolithic water table is inferred to have been more stable, allowing for permanent moist soil. PMID:17810306

Robinson, P

1966-10-14

214

Automated Tracking of Whiskers in Videos of Head Fixed Rodents  

Microsoft Academic Search

We have developed software for fully automated tracking of vibrissae (whiskers) in high-speed videos (>500 Hz) of head-fixed, behaving rodents trimmed to a single row of whiskers. Performance was assessed against a manually curated dataset consisting of 1.32 million video frames comprising 4.5 million whisker traces. The current implementation detects whiskers with a recall of 99.998% and identifies individual whiskers

Nathan G. Clack; Daniel H. OConnor; Daniel Huber; Leopoldo Petreanu; Andrew Hires; Simon Peron; Karel Svoboda; Eugene W. Myers

2012-01-01

215

Evidence for secondary seed dispersal by rodents in Panama  

Microsoft Academic Search

Summary  The data presented show thatVirola nobilis (Myristicaceae), a bird\\/mammal-dispersed tree species in Panama, may also be dispersed by a terrestrial rodent, the agouti\\u000a (Dasyprocta punctata). Using a thread-marking method, we observed that agoutis scatterhoardedV. nobilis seeds that they found both singly or in clumps. Seed removal and seed burial rates were strongly affected by features of\\u000a forest habitats, such asV.

Pierre-Michel Forget; Tarek Milleron

1991-01-01

216

Tropical Cyclogenesis in a Tropical Wave Critical Layer: Easterly Waves  

NASA Technical Reports Server (NTRS)

The development of tropical depressions within tropical waves over the Atlantic and eastern Pacific is usually preceded by a "surface low along the wave" as if to suggest a hybrid wave-vortex structure in which flow streamlines not only undulate with the waves, but form a closed circulation in the lower troposphere surrounding the low. This structure, equatorward of the easterly jet axis, is identified herein as the familiar critical layer of waves in shear flow, a flow configuration which arguably provides the simplest conceptual framework for tropical cyclogenesis resulting from tropical waves, their interaction with the mean flow, and with diabatic processes associated with deep moist convection. The recirculating Kelvin cat's eye within the critical layer represents a sweet spot for tropical cyclogenesis in which a proto-vortex may form and grow within its parent wave. A common location for storm development is given by the intersection of the wave's critical latitude and trough axis at the center of the cat's eye, with analyzed vorticity centroid nearby. The wave and vortex live together for a time, and initially propagate at approximately the same speed. In most cases this coupled propagation continues for a few days after a tropical depression is identified. For easterly waves, as the name suggests, the propagation is westward. It is shown that in order to visualize optimally the associated Lagrangian motions, one should view the flow streamlines, or stream function, in a frame of reference translating horizontally with the phase propagation of the parent wave. In this co-moving frame, streamlines are approximately equivalent to particle trajectories. The closed circulation is quasi-stationary, and a dividing streamline separates air within the cat's eye from air outside.

Dunkerton, T. J.; Montgomery, M. T.; Wang, Z.

2009-01-01

217

Genotypes of pathogenic Leptospira spp isolated from rodents in Argentina.  

PubMed

Leptospirosis is the most widespread zoonosis in the world and significant efforts have been made to determine and classify pathogenic Leptospira strains. This zoonosis is maintained in nature through chronic renal infections of carrier animals, with rodents and other small mammals serving as the most important reservoirs. Additionally, domestic animals, such as livestock and dogs, are significant sources of human infection. In this study, a multiple-locus variable-number tandem repeat analysis (MLVA) was applied to genotype 22 pathogenic Leptospira strains isolated from urban and periurban rodent populations from different regions of Argentina. Three MLVA profiles were identified in strains belonging to the species Leptospira interrogans (serovars Icterohaemorrhagiae and Canicola); one profile was observed in serovar Icterohaemorrhagiae and two MLVA profiles were observed in isolates of serovars Canicola and Portlandvere. All strains belonging to Leptospira borgpetersenii serovar Castellonis exhibited the same MLVA profile. Four different genotypes were isolated from urban populations of rodents, including both mice and rats and two different genotypes were isolated from periurban populations. PMID:24676656

Loffler, Sylvia Grune; Pavan, Maria Elisa; Vanasco, Bibiana; Samartino, Luis; Suarez, Olga; Auteri, Carmelo; Romero, Graciela; Brihuega, Bibiana

2014-04-01

218

Genotypes of pathogenic Leptospira spp isolated from rodents in Argentina  

PubMed Central

Leptospirosis is the most widespread zoonosis in the world and significant efforts have been made to determine and classify pathogenic Leptospira strains. This zoonosis is maintained in nature through chronic renal infections of carrier animals, with rodents and other small mammals serving as the most important reservoirs. Additionally, domestic animals, such as livestock and dogs, are significant sources of human infection. In this study, a multiple-locus variable-number tandem repeat analysis (MLVA) was applied to genotype 22 pathogenic Leptospira strains isolated from urban and periurban rodent populations from different regions of Argentina. Three MLVA profiles were identified in strains belonging to the species Leptospira interrogans (serovars Icterohaemorrhagiae and Canicola); one profile was observed in serovar Icterohaemorrhagiae and two MLVA profiles were observed in isolates of serovars Canicola and Portlandvere. All strains belonging to Leptospira borgpetersenii serovar Castellonis exhibited the same MLVA profile. Four different genotypes were isolated from urban populations of rodents, including both mice and rats and two different genotypes were isolated from periurban populations.

Loffler, Sylvia Grune; Pavan, Maria Elisa; Vanasco, Bibiana; Samartino, Luis; Suarez, Olga; Auteri, Carmelo; Romero, Graciela; Brihuega, Bibiana

2014-01-01

219

Allometric relations of neotropical small rodents (Sigmodontinae) in anthropogenic environments.  

PubMed

The present study aims at assessing allometric relationships in the Sigmodontinae rodents (Calomys tener, Akodon cf. montensis, Necromys lasiurus, Oligoryzomys flavescens, and Oligoryzomys nigripes), and morphological variation among different habitats in human-dominated environments in Southeastern Brazil. We captured rodents using pitfall traps placed in Eucalyptus plantations, abandoned pastures, and remnants of secondary native vegetation, and took the following measurements: body mass, total length, body length, left hind foot length, and left ear length. Males were usually larger than females, except in N. lasiurus. There was no intraspecific difference in body condition among habitats, suggesting that Eucalyptus may not have a deleterious effect upon its residents. However, A. cf montensis from Eucalyptus plantations had longer feet than those from other vegetation associations, suggesting a possible adaptive response to the lower cover in the plantation environment, and its consequent higher predation risk, or alternatively that only individuals with greater dispersal ability are found in Eucalyptus plantations. Future studies should investigate a possible co-evolutionary predator-prey relationship, including rapid evolution by Sigmodontinae rodents in anthropogenic landscapes. PMID:23829219

Rosalino, Luís M; Martin, Paula S; Gheler-Costa, Carla; Lopes, Paula C; Verdade, Luciano M

2013-07-01

220

A Fully Automated High-Throughput Training System for Rodents  

PubMed Central

Addressing the neural mechanisms underlying complex learned behaviors requires training animals in well-controlled tasks, an often time-consuming and labor-intensive process that can severely limit the feasibility of such studies. To overcome this constraint, we developed a fully computer-controlled general purpose system for high-throughput training of rodents. By standardizing and automating the implementation of predefined training protocols within the animal’s home-cage our system dramatically reduces the efforts involved in animal training while also removing human errors and biases from the process. We deployed this system to train rats in a variety of sensorimotor tasks, achieving learning rates comparable to existing, but more laborious, methods. By incrementally and systematically increasing the difficulty of the task over weeks of training, rats were able to master motor tasks that, in complexity and structure, resemble ones used in primate studies of motor sequence learning. By enabling fully automated training of rodents in a home-cage setting this low-cost and modular system increases the utility of rodents for studying the neural underpinnings of a variety of complex behaviors.

Poddar, Rajesh; Kawai, Risa; Olveczky, Bence P.

2013-01-01

221

Rodent Models of Depression: Neurotrophic and Neuroinflammatory Biomarkers  

PubMed Central

Rodent models are an indispensable tool for studying etiology and progress of depression. Since interrelated systems of neurotrophic factors and cytokines comprise major regulatory mechanisms controlling normal brain plasticity, impairments of these systems form the basis for development of cerebral pathologies, including mental diseases. The present review focuses on the numerous experimental rodent models of depression induced by different stress factors (exteroceptive and interoceptive) during early life (including prenatal period) or adulthood, giving emphasis to the data on the changes of neurotrophic factors and neuroinflammatory indices in the brain. These parameters are closely related to behavioral depression-like symptoms and impairments of neuronal plasticity and are both gender- and genotype-dependent. Stress-related changes in expression of neurotrophins and cytokines in rodent brain are region-specific. Some contradictory data reported by different groups may be a consequence of differences of stress paradigms or their realization in different laboratories. Like all experimental models, stress-induced depression-like conditions are experimental simplification of clinical depression states; however, they are suitable for understanding the involvement of neurotrophic factors and cytokines in the pathogenesis of the disease—a goal unachievable in the clinical reality. These major regulatory systems may be important targets for therapeutic measures as well as for development of drugs for treatment of depression states.

Stepanichev, Mikhail; Dygalo, Nikolay N.; Grigoryan, Grigory; Shishkina, Galina T.; Gulyaeva, Natalia

2014-01-01

222

Effect of cage-change frequency on rodent breeding performance.  

PubMed

Many people who work in laboratory rodent breeding facilities believe that disrupting certain sensitive rodent lines will result in increased breeding failures and loss of newborn pups. To evaluate this hypothesis, the authors assessed the effect of cage-change frequency on the breeding performances of a mouse strain (C57BL/6NTac) and a rat stock (NTac:NIH-Whn) that were thought to be sensitive to disruption. As per recommendations in the Guide for the Care and Use of Laboratory Animals, personnel changed one half of the breeding cages weekly, regardless of the presence of newborn pups. The other breeding cages were also changed weekly, unless newborn pups were present, in which case the cages were not changed until the following week. The authors assessed breeding performance by calculating the production efficiency index (the total number of pups that survived to weaning divided by the total number of actively breeding females). Breeding performance did not differ significantly between rodents whose cages were changed weekly and those whose pups were not disturbed. PMID:20485357

Sanderson, Amy E; Multari, Heather M; Lohmiller, Jeffrey J; Boutin, Samuel R

2010-06-01

223

Towards an integrative model of sociality in caviomorph rodents  

PubMed Central

In the late 1990s and early 2000s it was recognized that behavioral ecologists needed to study the sociality of caviomorph rodents (New World hystricognaths) before generalizations about rodent sociality could be made. Researchers identified specific problems facing individuals interested in caviomorph sociality, including a lack of information on the proximate mechanisms of sociality, role of social environment in development, and geographical or intraspecific variation in social systems. Since then researchers have described the social systems of many previously understudied species, including some with broad geographical ranges. Researchers have done a good job of determining the role of social environments in development and identifying the costs and benefits of social living. However, relatively little is known about the proximate mechanisms of social behavior and fitness consequences, limiting progress toward the development of integrative (evolutionary-mechanistic) models for sociality. To develop integrative models behavioral ecologists studying caviomorph rodents must generate information on the fitness consequences of different types of social organization, brain mechanisms, and endocrine substrates of sociality. We review our current understanding and future directions for research in these conceptual areas. A greater understanding of disease ecology, particularly in species carrying Old World parasites, is needed before we can identify potential links between social phenotypes, mechanism, and fitness.

Hayes, Loren D.; Burger, Joseph Robert; Soto-Gamboa, Mauricio; Sobrero, Raul; Ebensperger, Luis A

2012-01-01

224

Sexual Selection Halts the Relaxation of Protamine 2 among Rodents  

PubMed Central

Sexual selection has been proposed as the driving force promoting the rapid evolutionary changes observed in some reproductive genes including protamines. We test this hypothesis in a group of rodents which show marked differences in the intensity of sexual selection. Levels of sperm competition were not associated with the evolutionary rates of protamine 1 but, contrary to expectations, were negatively related to the evolutionary rate of cleaved- and mature-protamine 2. Since both domains were found to be under relaxation, our findings reveal an unforeseen role of sexual selection: to halt the degree of degeneration that proteins within families may experience due to functional redundancy. The degree of relaxation of protamine 2 in this group of rodents is such that in some species it has become dysfunctional and it is not expressed in mature spermatozoa. In contrast, protamine 1 is functionally conserved but shows directed positive selection on specific sites which are functionally relevant such as DNA-anchoring domains and phosphorylation sites. We conclude that in rodents protamine 2 is under relaxation and that sexual selection removes deleterious mutations among species with high levels of sperm competition to maintain the protein functional and the spermatozoa competitive.

Luke, Lena; Vicens, Alberto; Serra, Francois; Luque-Larena, Juan Jose; Dopazo, Hernan; Roldan, Eduardo R. S.; Gomendio, Montserrat

2011-01-01

225

Tropical Depression Alex hits Yucatan Peninsula  

NASA Video Gallery

NASA's TRMM spacecraft observed this view of Tropical Depression Alex on June 27, 2010 at 2214 UTC (6:14 PM EST). Tropical depression Alex was near the western coast of Mexico's Yucatan Peninsula. ...

226

Problem Oriented Differential Diagnosis of Tropical Diseases.  

National Technical Information Service (NTIS)

A problem oriented differential diagnosis of tropical diseases was written for primary care physicians. The text describes the basic principles of travel medicine, survival in the tropics, and heat injury. Tables organizing the incubation period and geogr...

K. T. Mason

1989-01-01

227

Tropical Storm Debby Moves into Atlantic  

NASA Video Gallery

An animation of satellite observations shows the progression of Tropical Storm Debby from June 25-27, 2012. The animation shows that Tropical Storm Debby's center move from the northeastern Gulf of...

228

Forest rodents provide directed dispersal of Jeffrey pine seeds  

USGS Publications Warehouse

Some species of animals provide directed dispersal of plant seeds by transporting them nonrandomly to microsites where their chances of producing healthy seedlings are enhanced. We investigated whether this mutualistic interaction occurs between granivorous rodents and Jeffrey pine (Pinus Jeffreyi) in the eastern Sierra Nevada by comparing the effectiveness of random abiotic seed dispersal with the dispersal performed by four species of rodents: deer mice (Peromyscus maniculatus), yellow-pine and long-eared chipmunks (Tamias amoenus and T. quadrimaculatus), and golden-mantled ground squirrels (Spermophilus lateralis). We conducted two caching studies using radio-labeled seeds, the first with individual animals in field enclosures and the second with a community of rodents in open forest. We used artificial caches to compare the fates of seeds placed at the range of microsites and depths used by animals with the fates of seeds dispersed abiotically. Finally, we examined the distribution and survival of naturally establishing seedlings over an eight-year period. Several lines of evidence suggested that this community of rodents provided directed dispersal. Animals preferred to cache seeds in microsites that were favorable for emergence or survival of seedlings and avoided caching in microsites in which seedlings fared worst. Seeds buried at depths typical of animal caches (5-25 mm) produced at least five times more seedlings than did seeds on the forest floor. The four species of rodents differed in the quality of dispersal they provided. Small, shallow caches made by deer mice most resembled seeds dispersed by abiotic processes, whereas many of the large caches made by ground squirrels were buried too deeply for successful emergence of seedlings. Chipmunks made the greatest number of caches within the range of depths and microsites favorable for establishment of pine seedlings. Directed dispersal is an important element of the population dynamics of Jeffrey pine, a dominant tree species in the eastern Sierra Nevada. Quantifying the occurrence and dynamics of directed dispersal in this and other cases will contribute to better understanding of mutualistic coevolution of plants and animals and to more effective management of ecosystems in which directed dispersal is a keystone process. ?? 2009 by the Ecological society of America.

Briggs, J. S.; Wall, S. B. V.; Jenkins, S. H.

2009-01-01

229

International Center for Tropical Agriculture  

NSDL National Science Digital Library

From cassavas to papayas, the International Center for Tropical Agriculture is concerned with the viability of crops across the world. Specifically, their stated mission is "to reduce hunger and poverty in the tropics through collaborative research that improves agricultural productivity and natural resource management." From their homepage, visitors can read press releases and statements about their most recent findings, and also look over timely documents such as "Integrated Soil Fertility Management in the Tropics" as well as their annual report. The "Research" section is another good place to wander around, as it contains reports on two of their primary areas of interest: agrobiodiversity and the interaction between people and agroecosystems. Finally, it is worth noting that many of the materials here are also available in Spanish.

230

Transitions between Andean and Amazonian centers of endemism in the radiation of some arboreal rodents  

PubMed Central

Background The tropical Andes and Amazon are among the richest regions of endemism for mammals, and each has given rise to extensive in situ radiations. Various animal lineages have radiated ex situ after colonizing one of these regions from the other: Amazonian clades of dendrobatid frogs and passerine birds may have Andean ancestry, and transitions from the Amazon to Andes may be even more common. To examine biogeographic transitions between these regions, we investigated the evolutionary history of three clades of rodents in the family Echimyidae: bamboo rats (Dactylomys-Olallamys-Kannabateomys), spiny tree-rats (Mesomys-Lonchothrix), and brush-tailed rats (Isothrix). Each clade is distributed in both the Andes and Amazonia, and is more diverse in the lowlands. We used two mitochondrial (cyt-b and 12S) and three nuclear (GHR, vWF, and RAG1) markers to reconstruct their phylogenetic relationships. Tree topologies and ancestral geographic ranges were then used to determine whether Andean forms were basal to or derived from lowland radiations. Results Four biogeographic transitions are identified among the generic radiations. The bamboo rat clade unambiguously originated in the Amazon ca. 9 Ma, followed by either one early transition to the Andes (Olallamys) and a later move to the Amazon (Dactylomys), or two later shifts to the Andes (one in each genus). The Andean species of both Dactylomys and Isothrix are sister to their lowland species, raising the possibility that highland forms colonized the Amazon Basin. However, uncertainty in their reconstructed ancestral ranges obscures the origin of these transitions. The lone Andean species of Mesomys is confidently nested within the lowland radiation, thereby indicating an Amazon-to-Andes transition ca. 2 Ma. Conclusions Differences in the timing of these biogeographic transitions do not appear to explain the different polarities of these trees. Instead, even within the radiation of a single family, both Andean and Amazonian centers of endemism appear enriched by lineages that originated in the other region. Our survey of other South American lineages suggests a pattern of reciprocal exchange between these regions—among mammals, birds, amphibians, and insects we found no fewer than 87 transitions between the Andes and Amazon from Miocene-Pleistocene. Because no clear trend emerges between the timing and polarity of transitions, or in their relative frequency, we suggest that reciprocal exchange between tropical highland and lowland faunas in South America has been a continual process since ca. 12 Ma.

2013-01-01

231

Sustained high levels of neuregulin-1 in the longest-lived rodents; a key determinant of rodent longevity.  

PubMed

Naked mole-rats (Heterocephalus glaber), the longest-lived rodents, live 7-10 times longer than similarly sized mice and exhibit normal activities for approximately 75% of their lives. Little is known about the mechanisms that allow them to delay the aging process and live so long. Neuregulin-1 (NRG-1) signaling is critical for normal brain function during both development and adulthood. We hypothesized that long-lived species will maintain higher levels of NRG-1 and that this contributes to their sustained brain function and concomitant maintenance of normal activity. We monitored the levels of NRG-1 and its receptor ErbB4 in H. glaber at different ages ranging from 1 day to 26 years and found that levels of NRG-1 and ErbB4 were sustained throughout development and adulthood. In addition, we compared seven rodent species with widely divergent (4-32 year) maximum lifespan potential (MLSP) and found that at a physiologically equivalent age, the longer-lived rodents had higher levels of NRG-1 and ErbB4. Moreover, phylogenetic independent contrast analyses revealed that this significant strong correlation between MLSP and NRG-1 levels was independent of phylogeny. These results suggest that NRG-1 is an important factor contributing to divergent species MLSP through its role in maintaining neuronal integrity. PMID:22103690

Edrey, Yael H; Casper, Diana; Huchon, Dorothee; Mele, James; Gelfond, Jonathan A; Kristan, Deborah M; Nevo, Eviatar; Buffenstein, Rochelle

2012-04-01

232

The intact immature rodent uterotrophic bioassay: possible effects on assay sensitivity of vomeronasal signals from male rodents and strain differences.  

PubMed Central

The vomeronasal organ in rodents is an important social and sexual signaling pathway. We have investigated whether the housing of intact immature females in close proximity to mature males would interfere with the sensitivity of the immature rodent uterotrophic bioassay as the result of vomeronasal signals transmitted by male urinary proteins. The hypothesis was that the proximity of males might induce early puberty, thereby increasing mean uterine weight and reducing the responsiveness of the assay. The hypothesis was tested in both rats and mice by housing mature males above immature females, separated only by a wire screen, for 3 days and determining possible changes in uterine weight. The results were negative. Neither the mean uterine weight nor the group mean standard deviation of the uterine weights were changed in the uterotrophic bioassay. Given that the timing of sexual maturation may vary with the strain of mouse used, we also evaluated the sensitivity of the immature mouse uterotrophic assay to diethylstilbestrol (DES) using four strains of mice. Similar sensitivity was observed for the CD-1, C57Bl6, and Alpk strains, but B6CBF(1) mice were marginally less sensitive to DES than were the other strains. These findings add to earlier data indicating the robustness of the rodent uterotrophic assay protocol.

Ashby, John; Owens, William; Odum, Jenny; Tinwell, Helen

2003-01-01

233

Glacial climate in the tropics  

SciTech Connect

New findings have caused ideas about the Earth`s climate during the Pleistocene glaciation to change. A consensus seems to be forming that during times of glaciation, climatic conditions in the tropics were quite different from those today. However still to be explained is why strontium-calcium measurements on corals and moble gas measurements of ground water suggest a tropical cooling of 4-6 C while foraminiferal speciation, oxygen isotope, and alkenone results suggest a cooling of no more than 3 C. This article discusses different aspects of the debate. 9 refs., 1 fig.

Broecker, W. [Columbia Univ., Palisades, NY (United States)

1996-06-28

234

Reflections on the tropical deforestation crisis  

Microsoft Academic Search

Tropical forests do far more than sustain biodiversity; they are homes to indigenous peoples, pharmacopeias of natural products, and provide vital ecosystem services, such as flood amelioration and soil conservation. At regional and global scales, tropical forests also have a major influence on carbon storage and climate. I highlight these benefits, then assess the pattern and pace of tropical forest

William F. Laurance

1999-01-01

235

Tropical hyperplane arrangements and oriented matroids  

Microsoft Academic Search

We study the combinatorial properties of a tropical hyperplane arrangement. We define tropical oriented matroids, and prove\\u000a that they share many of the properties of ordinary oriented matroids. We show that a tropical oriented matroid determines\\u000a a subdivision of a product of two simplices, and conjecture that this correspondence is a bijection.

Federico Ardila; Mike Develin

2009-01-01

236

Sustaining biodiversity in ancient tropical countryside  

Microsoft Academic Search

With intensifying demands for food and biofuels, a critical threat to biodiversity is agricultural expansion into native tropical ecosystems. Tropical agriculture, particularly intensive agriculture, often supports few native organisms, and consequently has been largely overlooked in conservation planning; yet, recent work in the Neotropics demonstrates that tropical agriculture with certain features can support significant biodiversity, decades after conversion to farmland.

Jai Ranganathan; R. J. Ranjit Daniels; M. D. Subash Chandran; Paul R. Ehrlich; Gretchen C. Daily

2008-01-01

237

The Scatter in Tropical Average Precipitation Anomalies  

Microsoft Academic Search

Tropical mean precipitation anomalies ^P9& for 3-month averages appear quite scattered in relation to tropical average sea surface temperature (SST) anomalies ^& , based on examination of a number of observational T9 s datasets and of atmospheric general circulation model (GCM) results. Even though SST is locally important for determining precipitation, for a given warm SST anomaly, the tropical average

HUI S UA; NDJ. DAVID NEELIN

2003-01-01

238

Tropical rainforest canopies and climate change  

Microsoft Academic Search

There is less certainty about the impact of climate change on tropical rainforests than on temperate forests because of the comparative lack of background data and because few large scale experiments have been, and are being, carried out in tropical rainforests. Many of the factors critical to the future of tropical rainforests concern canopies, the key processes that take place

NIGEL E. STORK; J. BALSTON; G. D. FARQUHAR; P. J. FRANKS; J. A. M. HOLTUM; M. J. LIDDELL

2007-01-01

239

Tropical Fevers: C. Important human parasitic fevers of the tropics  

Microsoft Academic Search

characterizes a number of disease states.1 It is a common and very important presenting symptom of many tropical diseases, including many important parasitic infections. Making the correct diagnosis and selecting effective therapy is challenging but potentially life-saving. It is essential to remember that fever is more likely to be a manifestation of a \\

David N. Dürrheim

240

Cross-reactivity of secondary antibodies against African rodents and application for sero-surveillance.  

PubMed

A total of 466 rodents were captured in the Republic of Zambia from 2006 to 2010. Based on morphological observations and phylogenetic analyses of mitochondrial gene sequences, rodents were divided into 10 groups consisting of 39 Rattus rodents, 263 multimammate rats, 18 other Murinae rodents, 95 gerbils, 11 pouched mice, 1 giant-pouched rat, 38 fat mice and 1 dormouse. Rodent antibodies except that from Rattus were examined for their cross-reactivity to commercially available antibody detection reagents. Anti-mouse immunoglobulin G (IgG) was most cross-reactive to heterologous antibodies including multimammate rat, gerbil, pouched mouse and fat mouse. Thus, anti-mouse IgG would be a useful detection tool in serological examination of the Zambian rodent population. Preliminary sero-surveillance for plague, leptospirosis and hantavirus infection was performed by ELISA. PMID:23386359

Nakamura, Ichiro; Hang'ombe, Bernard Mudenda; Sawa, Hirofumi; Kobayashi, Shintaro; Orba, Yasuko; Ishii, Akihiro; Thomas, Yuka; Isozumi, Rie; Yoshimatsu, Kumiko; Mweene, Aaron S; Takada, Ayato; Sugimoto, Chihiro; Arikawa, Jiro

2013-01-01

241

The African lily Massonia depressa (Hyacinthaceae) the First Monocotyledon Discovered to be Pollinated by Rodents  

NSDL National Science Digital Library

A nocturnal rodent, Gerbilluris paeba, feeds on the copious amounts of jelly-like nectar produced by flowers of the African lily Massonia depressa (Hyacinthaceae). This lily, which has flowers situated at ground level, is the first monocotyledon discovered to be pollinated by rodents. The striking similarities between the flowers of M. depressa and those of unrelated rodent-pollinated Protea spp. (Proteaceae) provide strong support for the concept of convergent floral syndromes.

Anton Pauw (University of Cape Town, Department of Botany ADR;POSTAL); Steve Johnson (University of Natal;School of Botany and Zoology ADR;POSTAL)

2004-03-09

242

Intensity of prehistoric tropical cyclones  

NASA Astrophysics Data System (ADS)

Prediction of future tropical cyclone climate scenarios requires identification of quasi-periodicities at a variety of temporal scales. Extension of records to identify trends at century and millennial scales is important, but to date the emerging field of paleotempestology has been hindered by the lack of a suitable methodology to discern the intensity of prehistoric storms. Here a technique to quantify the central pressure of prehistoric tropical cyclones is presented in detail and demonstrated for the tropical southwest Pacific region. The importance of extending records to century time scales is highlighted for northeast Australia, where a virtual absence of category 5 cyclones during the 20th century stands in contrast to an active period of severe cyclogenesis during the previous century. Several land crossing storms during the 19th century achieved central pressures lower than that ever recorded historically and close to the theoretical thermodynamic limit of storms for the region. This technique can be applied to all tropical and subtropical regions globally and will assist in obtaining more realistic predictions for future storm scenarios with implications for insurance premiums, urban and infrastructural design, and emergency planning.

Nott, Jonathan F.

2003-04-01

243

Tropical Storm Allison Progression (WMS)  

NSDL National Science Digital Library

Tropical Storm Allison began just five days into the 2001 hurricane season. Allison formed in the warm waters of the Gulf of Mexico, and dumped an enormous amount of rain on Texas, Louisiana, Florida, and other states in the southeastern United States.

Sokolowsky, Eric; Perkins, Lori; Kuring, Norman; Feldman, Gene

2004-03-11

244

Skin Diseases in the Tropics.  

ERIC Educational Resources Information Center

Common skin diseases are prevalent in tropical countries because of extreme weather conditions, mediocre hygiene, and lack of adequate treatment of infectious dermatoses. This guide describes the major endemic skin diseases and their signs for the purpose of helping unspecialized health agents train themselves and determine when a patient should…

Mahe, Antoine; And Others

1994-01-01

245

Tropical Cyclone Ensemble Data Assimilation.  

National Technical Information Service (NTIS)

The ultimate goal of this project is to demonstrate that in the presence of tropical cyclones (TCs), a multi-scale approach for data assimilation can significantly enhance the analyses and the ensuing forecasts. Our multiscale approach is based on couplin...

I. Szunyogh

2012-01-01

246

Tropical Depression Kyle, October 10, 2002  

NSDL National Science Digital Library

Tropical Depression Kyle is expected to reach the northeast Florida coast in 24 hours. It is currently packing sustained winds of 30 mph. The storm developed on September 20, 2002 and has been classified as a sub-tropical depression, tropical storm, hurricane, tropical storm, and now a tropical depression. The visualization zooms down to the storm and then shows the overall rain structure of Kyle. Yellow represents areas where at least 0.5 inches of rain fell per hour. Green shows at least 1.0 inch of rain, and red depicts more than 2.0 inches of rain per hour.

Perkins, Lori; Halverson, Jeff

2002-10-10

247

Black Swan Tropical Cyclones  

NASA Astrophysics Data System (ADS)

Virtually all assessments of tropical cyclone risk are based on historical records, which are limited to a few hundred years at most. Yet stronger TCs may occur in the future and at places that have not been affected historically. Such events lie outside the realm of historically based expectations and may have extreme impacts. Their occurrences are also often made explainable after the fact (e.g., Hurricane Katrina). We nickname such potential future TCs, characterized by rarity, extreme impact, and retrospective predictability, "black swans" (Nassim Nicholas Taleb, 2007). As, by definition, black swan TCs have yet to happen, statistical methods that solely rely on historical track data cannot predict their occurrence. Global climate models lack the capability to predict intense storms, even with a resolution as high as 14 km (Emanuel et al. 2010). Also, most dynamic downscaling methods (e.g., Bender et al. 2010) are still limited in horizontal resolution and are too expensive to implement to generate enough events to include rare ones. In this study, we apply a simpler statistical/deterministic hurricane model (Emanuel et al. 2006) to simulate large numbers of synthetic storms under a given (observed or projected) climate condition. The method has been shown to generate realistic extremes in various basins (Emanuel et al. 2008 and 2010). We also apply a hydrodynamic model (ADCIRC; Luettich et al. 1992) to simulate the storm surges generated by these storms. We then search for black swan TCs, in terms of the joint wind and surge damage potential, in the generated large databases. Heavy rainfall is another important TC hazard and will be considered in a future study. We focus on three areas: Tampa Bay in the U.S., the Persian Gulf, and Darwin in Australia. Tampa Bay is highly vulnerable to storm surge as it is surrounded by shallow water and low-lying lands, much of which may be inundated by a storm tide of 6 m. High surges are generated by storms with a broad spectrum of characteristics in our synthetic database, although no large surge has been recorded historically as only one moderate storm passed by the area. Tampa black swans are identified as those that move northward parallel to the west Florida coast with high intensities and resonant with the Florida-shelf edge waves to generate extreme surges up to 10 m in Tampa Bay. The Arabian Sea area has sea surface temperatures warm enough to support the development of severe TCs, but TC development has been limited by low humidity and high wind shear, and only one recorded TC (super cyclonic storm Gonu in 2007) moved close to the Persian Gulf, making landfall in Oman and Iran. Our analysis shows that black swan TCs can originate within the Persian Gulf and make landfall with high intensities in populous places; extreme surges over 9 m for Abu Dubai and Doha and over 7 m for Dubai are possible. Darwin experienced immense devastation from Cyclone Tracy of 1974, but the damage was mainly due to the strong winds (the surge was only about 1.6 m). Our analysis includes extremely intense black swan TCs that make landfall just south of Darwin, generating surges above 10 m; these results may prompt the city to reconsider its TC risk. We are currently analyzing the join probability of the extreme wind and surge of these black swan TCs to more clearly assess their full damage potentials.

Emanuel, K.; Lin, N.

2012-12-01

248

The Genetic Basis of Resistance to Anticoagulants in Rodents  

PubMed Central

Anticoagulant compounds, i.e., derivatives of either 4-hydroxycoumarin (e.g., warfarin, bromadiolone) or indane-1,3-dione (e.g., diphacinone, chlorophacinone), have been in worldwide use as rodenticides for >50 years. These compounds inhibit blood coagulation by repression of the vitamin K reductase reaction (VKOR). Anticoagulant-resistant rodent populations have been reported from many countries and pose a considerable problem for pest control. Resistance is transmitted as an autosomal dominant trait although, until recently, the basic genetic mutation was unknown. Here, we report on the identification of eight different mutations in the VKORC1 gene in resistant laboratory strains of brown rats and house mice and in wild-caught brown rats from various locations in Europe with five of these mutations affecting only two amino acids (Tyr139Cys, Tyr139Ser, Tyr139Phe and Leu128Gln, Leu128Ser). By recombinant expression of VKORC1 constructs in HEK293 cells we demonstrate that mutations at Tyr139 confer resistance to warfarin at variable degrees while the other mutations, in addition, dramatically reduce VKOR activity. Our data strongly argue for at least seven independent mutation events in brown rats and two in mice. They suggest that mutations in VKORC1 are the genetic basis of anticoagulant resistance in wild populations of rodents, although the mutations alone do not explain all aspects of resistance that have been reported. We hypothesize that these mutations, apart from generating structural changes in the VKORC1 protein, may induce compensatory mechanisms to maintain blood clotting. Our findings provide the basis for a DNA-based field monitoring of anticoagulant resistance in rodents.

Pelz, Hans-Joachim; Rost, Simone; Hunerberg, Mirja; Fregin, Andreas; Heiberg, Ann-Charlotte; Baert, Kristof; MacNicoll, Alan D.; Prescott, Colin V.; Walker, Anne-Sophie; Oldenburg, Johannes; Muller, Clemens R.

2005-01-01

249

Ghrelin Influences Novelty Seeking Behavior in Rodents and Men  

PubMed Central

Recent discoveries indicate an important role for ghrelin in drug and alcohol reward and an ability of ghrelin to regulate mesolimbic dopamine activity. The role of dopamine in novelty seeking, and the association between this trait and drug and alcohol abuse, led us to hypothesize that ghrelin may influence novelty seeking behavior. To test this possibility we applied several complementary rodent models of novelty seeking behavior, i.e. inescapable novelty-induced locomotor activity (NILA), novelty-induced place preference and novel object exploration, in rats subjected to acute ghrelin receptor (growth hormone secretagogue receptor; GHSR) stimulation or blockade. Furthermore we assessed the possible association between polymorphisms in the genes encoding ghrelin and GHSR and novelty seeking behavior in humans. The rodent studies indicate an important role for ghrelin in a wide range of novelty seeking behaviors. Ghrelin-injected rats exhibited a higher preference for a novel environment and increased novel object exploration. Conversely, those with GHSR blockade drastically reduced their preference for a novel environment and displayed decreased NILA. Importantly, the mesolimbic ventral tegmental area selective GHSR blockade was sufficient to reduce the NILA response indicating that the mesolimbic GHSRs might play an important role in the observed novelty responses. Moreover, in untreated animals, a striking positive correlation between NILA and sucrose reward behavior was detected. Two GHSR single nucleotide polymorphisms (SNPs), rs2948694 and rs495225, were significantly associated with the personality trait novelty seeking, as assessed using the Temperament and Character Inventory (TCI), in human subjects. This study provides the first evidence for a role of ghrelin in novelty seeking behavior in animals and humans, and also points to an association between food reward and novelty seeking in rodents.

Hansson, Caroline; Shirazi, Rozita H.; Naslund, Jakob; Vogel, Heike; Neuber, Corinna; Holm, Goran; Anckarsater, Henrik; Dickson, Suzanne L.; Eriksson, Elias; Skibicka, Karolina P.

2012-01-01

250

Synthesis of Polymerized Melanin by Cryptococcus neoformans in Infected Rodents  

PubMed Central

The ability of Cryptococcus neoformans to synthesize polymerized melanin in vitro has been associated with virulence, but it is unclear whether this fungus synthesizes polymerized melanin during infection. To study this question, we used two approaches: one involved the generation of monoclonal antibodies (MAbs) to melanin for use in immunohistochemical studies of C. neoformans-infected rodents, and the other sought to isolate fungal melanin from infected tissues. Digestion of in vitro-melanized C. neoformans cells with proteases, denaturant, and hot concentrated acid yields melanin particles that retain the shape of fungal cells and are therefore called melanin ghosts. BALB/c mice were immunized with melanin ghosts, and two immunoglobulin M MAbs to melanin were generated from the spleen of one mouse. Immunofluorescence analyses of lung and brain tissues of rodents infected with wild-type melanin-producing (Mel+) C. neoformans strains demonstrated binding of the MAbs to the fungal cell wall. No binding was observed when infections were performed with mutant albino (Mel?) C. neoformans strains. Particles with striking similarity to melanin ghosts were recovered after digestion of lung and brain tissues from Mel+ C. neoformans-infected rodents and were reactive with the MAbs to melanin. No particles were recovered from tissues infected with Mel? C. neoformans. A Mel+ C. neoformans strain grown on lung or brain homogenate agar became lightly pigmented and also yielded particles similar to melanin ghosts upon digestion, providing additional evidence that lung and brain tissues contain substrate for C. neoformans melanization. These results demonstrate that C. neoformans synthesizes polymerized melanin during infection, which has important implications for pathogenesis and antifungal drug development.

Rosas, Angel L.; Nosanchuk, Joshua D.; Feldmesser, Marta; Cox, Gary M.; McDade, Henry C.; Casadevall, Arturo

2000-01-01

251

Cell proliferation not associated with carcinogenesis in rodents and humans.  

PubMed

Cell proliferation has often been found to be associated with carcinogenesis in rodents and humans at different stages of the multistage carcinogenesis process. The multistage process includes initiation, promotion, and progression phases. At each phase, increasing the normal level of cell turnover of target cells may enhance carcinogenesis. However, we present evidence that normal levels of cell turnover, or increasing the rate of cell turnover at these different stages, do not necessarily lead to enhanced carcinogenesis. In normal tissues, the length of the cell cycle depends on the age of the host and varies from tissue to tissue. Tissues with normal short cell cycles, such as intestine and bone marrow, do not show a high rate of spontaneous tumors in most species. Cells with higher turnover should be more susceptible to carcinogens at the initiation stage of carcinogenesis if cell proliferation per se causes cancer and if these cells or their progeny survive. Cancer in humans is more often associated with specific etiological factors rather than with the natural proliferative rate of specific tissues. For many tissues of humans and rodents, age-related diseases develop in a progressive, irreversible manner. Often, naturally occurring chronic degenerative and inflammatory changes in a tissue (e.g., kidney, liver, heart, reproductive tract) lead to chronic regeneration of the damaged tissue. Yet, cancer is rarely found in these tissues. In rodent carcinogenesis experiments, chronic toxic lesions, accompanied by increases in normal levels of cell turnover, have sometimes been observed in target organs of nongenotoxic carcinogens. More often, however, organ-specific nongenotoxic toxins are not carcinogens. These toxins include compounds toxic for the liver, kidney, and nasal cavity. In 19 inhalation bioassays conducted by the National Toxicology Program, 5/5 nasal carcinogens and 12/14 nasal noncarcinogens caused nasal lesions usually associated with chronic cell proliferation. Although cell proliferation may contribute to multistage carcinogenesis, cell proliferation is not necessarily a tumor promoter or cocarcinogen. PMID:8013399

Ward, J M; Uno, H; Kurata, Y; Weghorst, C M; Jang, J J

1993-12-01

252

Reproductive Rates in Australian Rodents Are Related to Phylogeny  

PubMed Central

Background The native rodents of Australia are commonly divided into two groups based on the time of their colonization of the Sahulian continent, which encompasses Australia, New Guinea, and the adjacent islands. The first group, the “old endemics,” is a diverse assemblage of 34 genera that are descended from a single colonization of the continent during the Pliocene. A second group, the “new endemics,” is composed of several native Rattus species that are descended from a single colonization during the Pleistocene. Finally, a third group is composed of three non-native species of Rattus and Mus introduced into Australia by humans over the last 200 years. Previous studies have claimed that the three groups differ in their reproductive rates and that this variation in rates is associated with the unique environmental conditions across Australia. We examined these hypotheses using phylogenetically controlled methods. Methodology and Results We examined the relationship between the reproductive rates of the Australian rodents and the environmental variations across the continent, as well as the epoch of their colonization of the continent. Our results revealed no significant correlation with environmental variables but a significant association between colonization age and all the reproductive parameters examined. Discussion Based on a larger phylogeny of the subfamily Murinae, we showed that significant differences in reproductive rates among colonization groups are shared with their closest relatives outside Sahul. Therefore, the lower reproductive rates in the old endemics are more likely to be the result of phylogenetic history and conservation of traits than an adaptation to the Australian environment. In the new endemics, we found a trend of increasing reproductive rates with diversification. We suggest that the differences in reproductive rates of the old endemic rodents and the native Rattus represent alternative adaptive strategies that have allowed them to utilize similar ecological niches across Australia.

Geffen, Eli; Rowe, Kevin C.; Yom-Tov, Yoram

2011-01-01

253

Placentation in Sigmodontinae: a rodent taxon native to South America  

PubMed Central

Background Sigmodontinae, known as "New World rats and mice," is a large subfamily of Cricetidae for which we herein provide the first comprehensive investigation of the placenta. Methods Placentas of various gestational ages ranging from early pregnancy to near term were obtained for five genera, i.e. Necromys, Euryoryzomys, Cerradomys, Hylaeamys, and Oligoryzomys. They were investigated by means of histology, immunohistochemistry, a proliferation marker, DBA-lectin staining and transmission electron microscopy. Results The chorioallantoic placenta was organized in a labyrinthine zone, spongy zone and decidua and an inverted yolk sac persisted until term. The chorioallantoic placenta was hemotrichorial. The interhemal barrier comprised fetal capillary endothelium and three layers of trophoblast, an outermost, cellular layer and two syncytial ones, with interspersed trophoblast giant cells (TGC). In addition, accumulations of TGC occurred below Reichert's membrane. The junctional zone contained syncytial trophoblast, proliferative cellular trophoblast, glycogen cells and TGC that were situated near to the maternal blood channels. In three of the genera, TGC were also accumulated in distinct areas at the placental periphery. PAS-positive glycogen cells derived from the junctional zone invaded the decidua. Abundant maternal uNK cells with positive response to PAS, vimentin and DBA-lectin were found in the decidua. The visceral yolk sac was completely inverted and villous. Conclusion The general aspect of the fetal membranes in Sigmodontinae resembled that found in other cricetid rodents. Compared to murid rodents there were larger numbers of giant cells and in some genera these were seen to congregate at the periphery of the placental disk. Glycogen cells were found to invade the decidua but we did not identify trophoblast in the walls of the deeper decidual arteries. In contrast these vessels were surrounded by large numbers of uNK cells. This survey of wild-trapped specimens from five genera is a useful starting point for the study of placentation in an important subfamily of South American rodents. We note, however, that some of these rodents can be captive bred and recommend that future studies focus on the study of time dated pregnancies.

2011-01-01

254

Animal research. Activists win big on rodent, bird rules.  

PubMed

A federal judge last month ruled that animal-rights activists have the legal right to challenge U.S. Department of Agriculture rules that exempt the vast majority of research animals from federal regulation. Observers say that the ruling almost guarantees that the agency will extend regulations governing animal handling and housing to thousands of academic and industry laboratories that work with rodents and birds. Those new rules, say animal-care experts, could impose costly new requirements on labs that don't meet standards set by the private Association for Assessment and Accreditation of Laboratory Animal Care. PMID:10939943

Malakoff, D

2000-07-21

255

Ecologic studies of rodent reservoirs: their relevance for human health.  

PubMed Central

Within the past few years, the number of "new" human diseases associated with small-mammal reservoirs has increased dramatically, stimulating renewed interest in reservoir ecology research. A consistent, integrative approach to such research allows direct comparisons between studies, contributes to the efficient use of resources and data, and increases investigator safety. We outline steps directed toward understanding vertebrate host ecology as it relates to human disease and illustrate the relevance of each step by using examples from studies of hosts associated with rodent-borne hemorrhagic fever viruses.

Mills, J. N.; Childs, J. E.

1998-01-01

256

Hemorrhagic gastritis in free-living rodents in Idaho.  

PubMed

Between February 1992 and March 1994, four species of rodent from the Snake River Birds of Prey Area near Boise, Idaho (USA) were necropsied. Hemorrhagic gastritis was observed in 16 of 131 Townsend's ground squirrels (Spermophilus townsendii), one of 11 Ord's kangaroo rats (Dipodomys ordii) and the one Great Basin pocket mouse (Perognathus parvus) evaluated. No lesions were observed in 14 white-footed deer mice (Peromyscus maniculatus). Tissue from one Townsend's ground squirrel was negative for Helicobacter sp.-like bacteria. PMID:9359067

Wilber, P G; Duszynski, D W; Van Horne, B

1996-10-01

257

Nonhuman gamblers: lessons from rodents, primates, and robots  

PubMed Central

The search for neuronal and psychological underpinnings of pathological gambling in humans would benefit from investigating related phenomena also outside of our species. In this paper, we present a survey of studies in three widely different populations of agents, namely rodents, non-human primates, and robots. Each of these populations offers valuable and complementary insights on the topic, as the literature demonstrates. In addition, we highlight the deep and complex connections between relevant results across these different areas of research (i.e., cognitive and computational neuroscience, neuroethology, cognitive primatology, neuropsychiatry, evolutionary robotics), to make the case for a greater degree of methodological integration in future studies on pathological gambling.

Paglieri, Fabio; Addessi, Elsa; De Petrillo, Francesca; Laviola, Giovanni; Mirolli, Marco; Parisi, Domenico; Petrosino, Giancarlo; Ventricelli, Marialba; Zoratto, Francesca; Adriani, Walter

2014-01-01

258

Pulmonary Toxicity Studies of Lunar Dusts in Rodents  

NASA Technical Reports Server (NTRS)

NASA will build an outpost on the lunar surface for long-duration human habitation and research. The surface of the Moon is covered by a layer of fine, reactive dust, and the living quarters in the lunar outpost are expected to be contaminated by lunar dust. NASA established the Lunar Airborne Dust Toxicity Advisory Group (LADTAG) to evaluate the risk of exposure to the dust and to establish safe exposure limits for astronauts working in the lunar habitat. Because the toxicity of lunar dust is not known, LADTAG has recommended investigating its toxicity in the lungs of laboratory animals. After receiving this recommendation, NASA directed the JSC Toxicology Laboratory to determine the pulmonary toxicity of lunar dust in exposed rodents. The rodent pulmonary toxicity studies proposed here are the same as those proposed by the LADTAG. Studies of the pulmonary toxicity of a dust are generally done first in rodents by intratracheal instillation (ITI). This toxicity screening test is then followed by an inhalation study, which requires much more of the test dust and is labor intensive. We succeeded in completing an ITI study on JSC-1 lunar dust simulant in mice (Lam et al., Inhalation Toxicology 14:901-916, 2002, and Inhalation Toxicology 14: 917-928, 2002), and have conducted a pilot ITI study to examine the acute toxicity of an Apollo lunar (highland) dust sample. Preliminary results obtained by examining lung lavage fluid from dust-treated mice show that lunar dust was somewhat toxic (more toxic than TiO2, but less than quartz dust). More extensive studies have been planned to further examine lung lavage fluid for biomarkers of toxicity and lung tissues for histopathological lesions in rodents exposed to aged and activated lunar dust samples. In these studies, reference dusts (TiO2 and quartz) of known toxicities and have industrial exposure limits will be studied in parallel so the relative toxicity of lunar dust can be determined. The ITI results will also be useful for choosing an exposure concentration for the animal inhalation study on a selected lunar dust sample, which is included as a part of this proposal. The animal inhalation exposure will be conducted with lunar dust simulant prior to the study with the lunar dust. The simulant exposure will ensure that the study techniques used with actual lunar dust will be successful. The results of ITI and inhalation studies will reveal the toxicological risk of exposures and are essential for setting exposure limits on lunar dust for astronauts living in the lunar habitat.

Lam, Chiu-wing; James, John T.; Taylor, Larry

2008-01-01

259

Correlation of CO 2 pneumoperitoneal pressures between rodents and humans  

Microsoft Academic Search

Introduction  Many studies have reported on the effects of pneumoperitoneum in a rat model, using a wide range of intra-abdominal pressures.\\u000a The correlation between pneumoperitoneal pressures in rodents to pressures in humans has not been established. This study\\u000a evaluates changes in various physiological parameters in different pneumoperitoneum pressures in the rat model with a comparison\\u000a to known data in humans.\\u000a \\u000a \\u000a \\u000a Materials

Shmuel Avital; Refael Itah; Samuel Szomstein; Raul Rosenthal; Roye Inbar; Yehuda Sckornik; Avi Weinbroum

2009-01-01

260

Pathologic effects in rodents exposed to sodium combustion products  

SciTech Connect

Three species of rodents exhibited respiratory distress when exposed to aerosols of sodium combustion products, the major constituent of which was shown to be sodium carbonate. At the higher doses, animals died during or shortly after 2 hr exposures. Lesions, primarily involving the pharynx and larynx, included accumulation of mucus, vesiculation, and mucosal edema. Other lesions included edema and vesiculation of the anterior trachea, hemorrhage in the lungs, and severe gastric tympany. Basal epithelial cells of the posterior pharynx and anterior trachea had enlarged mitochondria following exposures of 1 hr or more.

Busch, R.H.; McDonald, K.E.; Briant, J.K.; Morris, J.E.; Graham, T.M.

1983-01-01

261

A protocol for a lung neovascularization model in rodents  

PubMed Central

By providing insight into the cellular events of vascular injury and repair, experimental model systems seek to promote timely therapeutic strategies for human disease. The goal of many current studies of neovascularization is to identify cells critical to the process and their role in vascular channel assembly. We propose here a protocol to analyze, in an in vivo rodent model, vessel and capillary remodeling (reorganization and growth) in the injured lung. Sequential analyses of stages in the assembly of vascular structures, and of relevant cell types, provide further opportunities to study the molecular and cellular determinants of lung neovascularization.

Jones, Rosemary C; Capen, Diane E; Petersen, Bodil; Jain, Rakesh K; Duda, Dan G

2009-01-01

262

[Monitoring populations of rodent reservoirs of zoonotic diseases : Projects, aims and results].  

PubMed

Rodents can harbor and transmit pathogens that can cause severe disease in humans, companion animals and livestock. Such zoonotic pathogens comprise more than two thirds of the currently known human pathogens. The epidemiology of some zoonotic pathogens, such as hantaviruses, can be linked to the population dynamics of the rodent host. In this case, during an outbreak of the rodent host population many human infections may occur. In other rodent-borne zoonotic diseases such phenomena are not known and in many cases the rodent host specificity of a given pathogen is unclear. The monitoring of relevant rodent populations and of the rodent-borne zoonotic pathogens is essential to (1) understand the distribution and epidemiology of pathogens and (2) develop forecasting tools to predict outbreaks of zoonoses. Presently, there are no systematic long-term monitoring programs in place for zoonoses in Germany. Rodent monitoring activities are largely restricted to the plant protection sector, such as for the common vole (Microtus arvalis) and forest-damaging rodents. However, during the last 10-15 years a number of specific research projects have been initiated and run for a few years and Norway rat (Rattus norvegicus) monitoring has been implemented in Hamburg and Lower Saxony. Based on close cooperation of federal and state authorities and research institutions these efforts could be utilized to gain information about the distribution and importance of rodent-borne zoonoses. Nevertheless, for the integration of rodent population dynamics and zoonotic disease patterns and especially for developing predictive models, long-term monitoring is urgently required. To establish a systematic long-term monitoring program, existing networks and cooperation need to be used, additional collaborators (e.g., pest control operators) should be included and synergetic effects of different scientific fields should be utilized. PMID:24781907

Jacob, J; Ulrich, R G; Freise, J; Schmolz, E

2014-05-01

263

Dynamics of oliveros virus infection in rodents in central Argentina.  

PubMed

Oliveros virus (OLV) is an arenavirus hosted by the sigmodontine rodent, Necromys benefactus, in central Argentina. We report a 3-year longitudinal field study of the dynamics of OLV infection in host populations from 15 localities in two provinces on the central Argentine pampa. There was an overall 3-year period immunofluorescent antibody prevalence of 25% in the host population, and infected hosts were found throughout the study area. Spill-over infection into common sympatric species was rare. Infection dynamics exhibited many of the patterns seen for other rodent-borne arenaviruses and hantaviruses, but had some unique characteristics. Host population density was highest in autumn and lowest in spring, while antibody prevalence was highest in spring and lowest in autumn. Virus transmission was horizontal: infection was strongly associated with age, reaching 45% prevalence in the oldest individuals, and prevalence of infection was equal among male and female hosts. Infection may have been associated with scars, which were also approximately equally distributed among male and female Necromys. PMID:17760514

Mills, James N; Alva, Herminia; Ellis, Barbara A; Wagoner, Kent D; Childs, James E; Calderón, Gladys; Enría, Delia A; Jahrling, Peter B

2007-01-01

264

Holocene Vegetation History from Fossil Rodent Middens near Arequipa, Peru  

NASA Astrophysics Data System (ADS)

Rodent ( Abrocoma, Lagidium, Phyllotis) middens collected from 2350 to 2750 m elevation near Arequipa, Peru (16°S), provide an ˜9600-yr vegetation history of the northern Atacama Desert, based on identification of >50 species of plant macrofossils. These midden floras show considerable stability throughout the Holocene, with slightly more mesophytic plant assemblages in the middle Holocene. Unlike the southwestern United States, rodent middens of mid-Holocene age are common. In the Arequipa area, the midden record does not reflect any effects of a mid-Holocene mega drought proposed from the extreme lowstand (100 m below modern levels, >6000 to 3500 yr B.P.) of Lake Titicaca, only 200 km east of Arequipa. This is perhaps not surprising, given other evidence for wetter summers on the Pacific slope of the Andes during the middle Holocene as well as the poor correlation of summer rainfall among modern weather stations in the central Andes-Atacama Desert. The apparent difference in paleoclimatic reconstructions suggests that it is premature to relate changes observed during the Holocene to changes in El Niño Southern Oscillation modes.

Holmgren, Camille A.; Betancourt, Julio L.; Rylander, Kate Aasen; Roque, Jose; Tovar, Oscar; Zeballos, Horacio; Linares, Eliana; Quade, Jay

2001-09-01

265

Measurement of ploidy and cell proliferation in the rodent liver.  

PubMed Central

In most investigations of cell proliferation in vivo, the population under study consists of mononuclear diploid cells that undergo replication via normal complete division cycles. Because the phenomena associated with the cell cycle are sequential, only one is normally measured and it is usually adequate to quantify the proliferative activity in one of two ways. The first involves labeling the cells undergoing semi-conservative DNA synthesis with a radioactive DNA precursor, preparing autoradiographs of histological sections, and counting labeled nuclei. The other commonly studied parameter of cell proliferation is mitotic activity. The livers of rats and mice, unlike those of other mammals, consist mainly of hepatocytes that contain two classes of cell with respect to nuclei and several ploidy classes. These classes of hepatocytes arise as the result of modified cell division cycles. The peculiar cytological composition of the rodent liver has, until recently, caused difficulties in the measurement and interpretation of cell ploidy and cell proliferation by the above methods. Flow cytometry and fluorescence-activated cell sorting used in conjunction with quantitative fluorescent stains for DNA and fluorescently labeled antibodies to bromodeoxyuridine have permitted the rapid and precise quantification of cell proliferative activity in the rodent liver. Studies using these techniques have revealed that proliferative activity of hepatocytes may occur in different subpopulations of cells depending on the kind of toxicological injury inflicted on the animal.

Styles, J A

1993-01-01

266

Seasonal variation in telomere length of a hibernating rodent  

PubMed Central

Small hibernating rodents have greater maximum lifespans and hence appear to age more slowly than similar-sized non-hibernators. We tested for a direct effect of hibernation on somatic maintenance and ageing by measuring seasonal changes in relative telomere length (RTL) in the edible dormouse Glis glis. Average RTL in our population did not change significantly over the hibernation season, and a regression model explaining individual variation in post-hibernation RTL suggested a significant negative effect of the reduction in body mass over the inactive hibernation period (an index of time spent euthermic), supporting the idea that torpor slows ageing. Over the active season, RTL on average decreased in sub-adults but increased in adults, supporting previous findings of greater telomere shortening at younger ages. Telomere length increase might also have been associated with reproduction, which occurred only in adults. Our study reveals how seasonal changes in physiological state influence the progress of life-history traits, such as somatic maintenance and ageing, in a small hibernating rodent.

Turbill, Christopher; Ruf, Thomas; Smith, Steve; Bieber, Claudia

2013-01-01

267

Axenic isolation of Giardia strains from primates and rodents.  

PubMed

During the examination of animals at the Poznan Zoological Gardens, attempts were made to isolate Giardia strains. Using an in vitro excystation procedure, eight samples of cysts from animals with asymptomatic giardiasis were inoculated on BI-S-33 medium. The ease of isolation and axenization of Giardia was surprising; five axenic isolates of Giardia, belonging to the G. duodenalis morphological group, were established from primates (slow loris, lesser slow loris and siamang) and from rodents (Gambian giant pouched rat and cuis). The growth of all isolates was abundant and similar; the peak number of trophozoites on the seventh day (depending on the Giardia isolate) was 2.3 X 10(6)-3.2 X 10(6) and generation times were 8.2-19.3 h. The easy establishment of these isolates confirmed that they belong to the G. duodenalis morphological group. The recent hypothesis that Giardia may be introduced to a human population from an animal source implies the necessity to isolate and differentiate parasite strains from various hosts. In this respect, the first isolation of Giardia strains from non-human primates and from rodents is of particular importance. PMID:2343527

Majewska, A C; Kasprzak, W

1990-02-01

268

Toxoplasmosis in naturally infected rodents in Belgrade, Serbia.  

PubMed

To assess the role of synanthropic rodents in the epidemiology of urban toxoplasmosis, Toxoplasma gondii infection was examined in 144 rats (Rattus norvegicus) and 12 mice (Mus musculus) captured using live animal traps in three locations in Belgrade city characterized by poor housing and degraded environment. In rats, specific IgG antibodies were detected by modified agglutination test in 22 (27.5%) of the 80 blood samples available. Toxoplasma brain cysts were microscopically detected in 11 (7.6%), and Toxoplasma DNA by real-time polymerase chain reaction was demonstrated in 15 (10.4%) animals. Of these, both cysts and Toxoplasma DNA were detected in five (3.5%) rats. In mice, cysts were observed in 3 (25%), but Toxoplasma DNA was detected in even 10 (83.3%) animals, including all 3 with morphologically recognized cysts. Being a link in the chain of Toxoplasma infection, the existence of urban rodent reservoirs of infection represents a public health risk. PMID:21028963

Vujani?, Marija; Ivovi?, Vladimir; Kataranovski, Milena; Nikoli?, Aleksandra; Bobi?, Branko; Klun, Ivana; Villena, Isabelle; Kataranovski, Dragan; Djurkovi?-Djakovi?, Olgica

2011-08-01

269

Functional Evolution of the Feeding System in Rodents  

PubMed Central

The masticatory musculature of rodents has evolved to enable both gnawing at the incisors and chewing at the molars. In particular, the masseter muscle is highly specialised, having extended anteriorly to originate from the rostrum. All living rodents have achieved this masseteric expansion in one of three ways, known as the sciuromorph, hystricomorph and myomorph conditions. Here, we used finite element analysis (FEA) to investigate the biomechanical implications of these three morphologies, in a squirrel, guinea pig and rat. In particular, we wished to determine whether each of the three morphologies is better adapted for either gnawing or chewing. Results show that squirrels are more efficient at muscle-bite force transmission during incisor gnawing than guinea pigs, and that guinea pigs are more efficient at molar chewing than squirrels. This matches the known diet of nuts and seeds that squirrels gnaw, and of grasses that guinea pigs grind down with their molars. Surprisingly, results also indicate that rats are more efficient as well as more versatile feeders than both the squirrel and guinea pig. There seems to be no compromise in biting efficiency to accommodate the wider range of foodstuffs and the more general feeding behaviour adopted by rats. Our results show that the morphology of the skull and masticatory muscles have allowed squirrels to specialise as gnawers and guinea pigs as chewers, but that rats are high-performance generalists, which helps explain their overwhelming success as a group.

Cox, Philip G.; Rayfield, Emily J.; Fagan, Michael J.; Herrel, Anthony; Pataky, Todd C.; Jeffery, Nathan

2012-01-01

270

Variations in Rodent Models of Type 1 Diabetes: Islet Morphology  

PubMed Central

Type 1 diabetes (T1D) is characterized by hyperglycemia due to lost or damaged islet insulin-producing ?-cells. Rodent models of T1D result in hyperglycemia, but with different forms of islet deterioration. This study focused on 1 toxin-induced and 2 autoimmune rodent models of T1D: BioBreeding Diabetes Resistant rats, nonobese diabetic mice, and Dark Agouti rats treated with streptozotocin. Immunochemistry was used to evaluate the insulin levels in the ?-cells, cell composition, and insulitis. T1D caused complete or significant loss of ?-cells in all animal models, while increasing numbers of ?-cells. Lymphocytic infiltration was noted in and around islets early in the progression of autoimmune diabetes. The loss of lymphocytic infiltration coincided with the absence of ?-cells. In all models, the remaining ?- and ?-cells regrouped by relocating to the islet center. The resulting islets were smaller in size and irregularly shaped. Insulin injections subsequent to induction of toxin-induced diabetes significantly preserved ?-cells and islet morphology. Diabetes in animal models is anatomically heterogeneous and involves important changes in numbers and location of the remaining ?- and ?-cells. Comparisons with human pancreatic sections from healthy and diabetic donors showed similar morphological changes to the diabetic BBDR rat model.

Novikova, Lesya; Smirnova, Irina V.; Dotson, Abby L.; Benedict, Stephen H.

2013-01-01

271

Imaging optical reflectance in rodent barrel and forelimb sensory cortex.  

PubMed

Novel neuroimaging techniques are extending the scope for studying dynamic brain function. We have developed a system which enables the repeatable imaging of rapid function in rodent primary somatosensory cortex (S-I), based on activity-related changes in its optical reflectance (intrinsic signals). The S-I cortices of anesthetized male Sprague-Dawley rats were exposed. Images were acquired with a slow-scan, cooled, charge-coupled device camera (CCD) through filters at 550, 610, and 850 nm before, during, and after contralateral stimulation (vibrissal deflection or forepaw stimulation). Images were divided by prestimulus controls and then averaged across 9-27 trials to produce maps of stimulus-related reflectance change. Optical activity had magnitude 10(-3) of baseline reflectance and consistently comprised two distinct spatiotemporal components over cortex, depending on paradigm. The diffuse signal at 610 nm begins 0.5-1 s after stimulus onset and has a duration of 4-5 s. The second signal is macrovenous and is delayed by 1 s. Similar response patterns were observed at 550 and 850 nm. Evoked potentials, recorded at sites inside and outside the zone of optical activity, confirmed the functional nature of these signals. Using a CCD we have imaged functional reflectance changes over rodent S-I which commence, peak, and extinguish over a time scale of seconds. This optical activity is consistent with the etiologies of microvascular recruitment and chromophore redox change. PMID:9343569

Narayan, S M; Santori, E M; Blood, A J; Burton, J S; Toga, A W

1994-06-01

272

Genital manifestations of tropical diseases  

PubMed Central

Genital symptoms in tropical countries and among returned travellers can arise from a variety of bacterial, protozoal, and helminthic infections which are not usually sexually transmitted. The symptoms may mimic classic sexually transmitted infections (STIs) by producing ulceration (for example, amoebiasis, leishmaniasis), wart-like lesions (schistosomiasis), or lesions of the upper genital tract (epididymo-orchitis caused by tuberculosis, leprosy, and brucellosis; salpingitis as a result of tuberculosis, amoebiasis, and schistosomiasis). A variety of other genital symptoms less suggestive of STI are also seen in tropical countries. These include hydrocele (seen with filariasis), which can be no less stigmatising than STI, haemospermia (seen with schistosomiasis), and hypogonadism (which may occur in lepromatous leprosy). This article deals in turn with genital manifestations of filariasis, schistosomiasis, amoebiasis, leishmaniasis, tuberculosis and leprosy and gives clinical presentation, diagnosis, and treatment.

Richens, J

2004-01-01

273

Tropical Wetlands as Carbon Sinks  

NASA Astrophysics Data System (ADS)

This presentation focuses on the tropical wetlands of sub-Saharan Africa. These are an understudied ecosystem in which large emergent grasses and sedges normally dominate and which have the potential to sequester significant amounts of carbon. Measurements of Net Primary Production of these wetlands show that they are some of the highest values recorded for any ecosystem. We have used eddy covariance to measure Net Ecosystem Exchange of pristine and disturbed wetlands and show that pristine systems can have sink strengths as strong as tropical forests while disturbed systems that have been reclaimed for agricultural purposes have a very much reduced carbon sink activity and may be net carbon sources. The management issues surrounding the use of these wetlands illustrate a direct conflict between the production of food crops for the local population and the maintenance of carbon sequestration as an ecosystem service.

Jones, M. B.; Saunders, M.

2007-12-01

274

Rodent repellent studies. IV. Preparation and properties of trinitrobenzene-aryl amine complexes  

USGS Publications Warehouse

Data are presented on methods of preparation, chemical arid physical characteristics, toxicity, and repellency to rodents of complexes of symmetrical trinitrohenzene with various aromatic amines: When applied in suitable carriers or incorporated in plastic .films, members of this series ofmaterials were shown to offer significant increases in time required by wild rodents to damage common packaging materials.

DeWitt, J.B.; Bellack, E.; Welch, J.F.

1953-01-01

275

An overview of the tasks used to test working memory in rodents  

Microsoft Academic Search

In rodents, working memory is a representation of an object, stimulus, or spatial location that is typically used within a testing session, but not between sessions, to guide behaviour. In this review we consider a number of the tasks used to assess this type of memory in the rodent, and highlight some of their limitations. Although the concept of working

Paul A. Dudchenko

2004-01-01

276

Lassa virus: seroepidemiological survey of rodents caught in Ekpoma and environs.  

PubMed

Of the 876 rodents caught in different parts of Ekpoma, Nigeria, and environs, 218 were Mastomys natalensis, while 658 were other rodents. Of the 218 M. natalensis caught, 102 (46.79%) were positive for complement fixing antibody to Lassa virus. PMID:15712534

Okoror, L E; Esumeh, F I; Agbonlahor, D E; Umolu, P I

2005-01-01

277

Anti-erosion stone bunds influence rodent dynamics and crop damage in Ethiopian highlands  

NASA Astrophysics Data System (ADS)

In areas of subsistence agriculture, a variety of soil conservation methods have been implemented in the last few decades to improve crop yields, however these can have unintended consequences such as providing habitat for rodent pests. We studied rodent population dynamics and estimated crop damage in high and low stone bund density fields for four cropping seasons in Tigray highlands, northern Ethiopia. Stone bunds are physical structures for soil and water conservation, and potentially habitat for rodents. We used a general model to relate the proportion of crop damage to rodent abundance, stone bund density and crop stages. We found a positive correlation between rodent abundance and crop damage, and significant variation in rodent abundance and crop damage between high and low stone bund density fields. Furthermore, crop damage also varied significantly between crop stages. We concluded that Mastomys awashensis and Arvicanthis dembeensis were the two most important crop pests in the highlands causing significant damage. Fields with high stone bund density (~10 m average distance apart) harbor more rodents and endure a significantly higher proportion of crop damage compared to fields with lower stone bund density (~15 m average distance apart). The fact that rodent abundances peaked during the reproductive stage of the crop and around harvest implies the need for management intervention before these crop stages are attained.

Meheretu, Yonas; Welegerima, Kiros; Teferi, Mekonen; Yirga, Gidey; Haile, Mitiku; Sluydts, Vincent; Bauer, Hans; Nyssen, Jan; Deckers, Jozef; Leirs, Herwig

2014-05-01

278

Prairie Rattlesnakes (Crotalus viridis) Respond to Rodent Blood with Chemosensory Searching  

Microsoft Academic Search

In Experiment I, homogenized rodent tissue was applied to the lips of prairie rattlesnakes (Crotalus viridis). This treatment produced elevated rates of tongue flicking compared to controls that received water, but the elevations seen following stimulation with homogenate were not as large as those seen after snakes struck prey. In Experiment II, water, rodent blood, and integumentary cues were applied

David Chiszar; Grant Hobika; Hobart M. Smith

1993-01-01

279

STUDY OF THE CHEMICAL AND BEHAVIORAL TOXICOLOGY OF SUBSTITUTE CHEMICALS IN MICROTINE RODENTS  

EPA Science Inventory

Acute oral LD50 and 30-day dietary subacute LC50 studies of 10 selected pesticides were evaluated in microtine rodents. As a means to developing new animal model systems, four species of microtine rodents including Microtus ochrogaster (MO), Microtus canicaudus (MC), Microtus pen...

280

THE USE OF CHEMICALS TO CONTROL FIELD RODENTS AND OTHER PREDATORS. AGRICULTURAL CHEMICALS TECHNOLOGY, NUMBER 5.  

ERIC Educational Resources Information Center

THE PURPOSE OF THIS GUIDE IS TO ASSIST TEACHERS IN PREPARING POST-SECONDARY STUDENTS FOR AGRICULTURAL CHEMICAL OCCUPATIONS. IT IS ONE OF A SERIES OF MODULES DEVELOPED BY A NATIONAL TASK FORCE ON THE BASIS OF DATA FROM STATE STUDIES. SECTIONS ARE (1) USE OF CHEMICALS FOR RODENT CONTROL AND ERADICATION, (2) TERMINOLOGY AND COMPUTATIONS, (3) RODENT

Ohio State Univ., Columbus. Center for Vocational and Technical Education.

281

Deletions in processed pseudogenes accumulate faster in rodents than in humans  

Microsoft Academic Search

Summary The relative rates of point nucleotide substitution and accumulation of gap events (deletions and insertions) were calculated for 22 human and 30 rodent processed pseudogenes. Deletion events not only outnumbered insertions (the ratio being 7?1 and 3?1 for human and rodent pseudogenes, respectively), but also the total length of deletions was greater than that of insertions. Compared with their

Dan Graur; Yuval Shuali; Wen-Hsiung Li

1989-01-01

282

DEVELOPING A PREDICTIVE SIMULATION MODEL FOR ANTIANDROGEN IMPACTS ON RODENT PROSTATE  

EPA Science Inventory

Developing a predictive simulation model for antiandrogen impacts on rodent prostate HA Barton1, RW Setzer1, LK Potter1,2 1US EPA, ORD, NHEERL, ETD, PKB, Research Triangle Park, NC and 2Curriculum in Toxicology, UNC, Chapel Hill, NC Alterations in rodent prostate wei...

283

Serosurvey of Wild Rodents for Hantaviruses in Panama, 2000-2002  

Microsoft Academic Search

Five hundred fifty-six samples rep- resenting 24 species of small mammals (two species of marsupials and 22 rodents) were col- lected in Panama between February 2000 and July 2002. The samples were examined for an- tibodies to hantaviruses by means of enzyme- linked immunosorbent assay or immunoblot as- says. The serologic results indicated that several rodent species might act as

Jorge Salazar-Bravo; Blas Armien; Gerardo Suzan; Anibal Armien; Luis A. Ruedas; Mario Avila

284

Video-Based Rodent Activity Measurement Using Near-Infrared Illumination  

Microsoft Academic Search

This paper describes a noninvasive video tracking system for measurement of rodent behavioral activity under near-infrared (NIR) illumination. This novel method allows tracking of motion in the dark, when rodents are generally most active, and also under visible light. Results of the system were validated through comparison with simultaneously recorded data using a widely-used NIR crossbeam-based tracking system

J. Brooks Zurn; Xianhua Jiang; Yuichi Motai

2005-01-01

285

Wide Distribution and Genetic Diversity of "Candidatus Neoehrlichia mikurensis" in Rodents from China  

PubMed Central

“Candidatus Neoehrlichia mikurensis” was detected by PCR in 4.0% (34/841) of the rodents tested in this study. The 34 rodents represented nine species from seven regions of China. Phylogenetic analyses based on the partial groEL and nearly entire 16S rRNA gene sequences of the agent revealed genetic diversity, which was correlated with its geographic origins.

Li, Hao; Jiang, Jiafu; Tang, Fang; Sun, Yi; Li, Zengde; Zhang, Weilong; Gong, Zhengda; Liu, Kun; Yang, Hong

2013-01-01

286

Chemoprophylaxis of Tropical Infectious Diseases  

PubMed Central

Travelers to tropical countries are at risk for a variety of infectious diseases. In some cases effective vaccinations are available, but for other infections chemoprophylaxis can be offered. Malaria prevention has become increasingly complex as Plasmodium species become resistant to available drugs. In certain high risk settings, antibiotics can be used to prevent leptospirosis, scrub typhus and other infections. Post-exposure prophylaxis is appropriate for selected virulent infections. In this article the evidence for chemoprophylaxis will be reviewed.

McBride, William J. H.

2010-01-01

287

Viral exanthems in the tropics.  

PubMed

Viral exanthems are a common problem in tropical regions, particularly affecting children. Most exanthems are transient and harmless, but some are potentially very dangerous. Pregnant women and malnourished or immunocompromised infants carry the greatest risk of adverse outcome. In this article, parvovirus B19; dengue and yellow fever; West Nile, Barmah Forest, Marburg, and Ebola viruses, and human herpesviruses; asymmetric periflexural exanthema of childhood; measles; rubella; enteroviruses; Lassa fever; and South American hemorrhagic fevers will be discussed. PMID:17350501

Carneiro, Sueli Coelho da Silva; Cestari, Tania; Allen, Samuel H; Ramos e-Silva, Marcia

2007-01-01

288

Affine Buildings and Tropical Convexity  

Microsoft Academic Search

The notion of convexity in tropical geometry is closely related to notions of convexity in the theory of affine buildings. We explore this relationship from a combinatorial and computational perspective. Our results include a convex hull algorithm for the Bruhat--Tits building of SL$_d(K)$ and techniques for computing with apartments and membranes. While the original inspiration was the work of Dress

Michael Joswig; Bernd Sturmfels; Josephine Yu

2007-01-01

289

Xenobiotics and tropical chronic pancreatitis  

Microsoft Academic Search

Summary  The prevalence of chronic pancreatitis in tropical zones is far higher than in temperate zones, but there is no explanation\\u000a for this difference. Detailed social, occupational, and dietary histories were taken from 79 patients attending two hospitals\\u000a in Madras, South India. There were 53 apparently sporadic cases with both pancreatic calculi and diabetes; six apparently\\u000a sporadic cases with noncalcific disease,

J. M. Braganza; S. John; I. Padmalayam; V. Mohanfl; M. Viswanathan; S. Chari; M. Madanagopalan

1990-01-01

290

Pollen analyses from a 50 000-yr rodent midden series in the southern Atacama Desert (25° 30 S)  

NASA Astrophysics Data System (ADS)

Precipitation in northern Chile is controlled by two great wind belts - the southern westerlies over the southern Atacama and points south (> 24° S) and the tropical easterlies over the northern and central Atacama Desert (16-24° S). At the intersection of these summer and winter rainfall regimes, respectively, is a Mars-like landscape consisting of expansive surfaces devoid of vegetation (i.e. absolute desert) except in canyons that originate high enough to experience runoff once every few years. Pollen assemblages from 39 fossil rodent middens in one of these canyons, Quebrada del Chaco (25° 30 S), were used to infer the history of vegetation and precipitation at three elevations (2670-2800 m; 3100-3200 m; 3450-3500 m) over the past 50 000 years. When compared to modern conditions and fossil records to the north and south, the pollen evidence indicates more winter precipitation at > 52, 40-33, 24-17 k cal. yr BP, more precipitation in both seasons at 17-14 k cal. yr BP, and more summer precipitation from 14-11 k cal.yrBP. Younger middens are scarce at Quebrada del Chaco, and the few Holocene samples indicate hyperarid conditions comparable to today. The only exception is a pollen assemblage that indicates a brief but significant interlude of increased winter precipitation in the last millennium. Copyright

Maldonado, Antonio; Betancourt, Julio L.; Latorre, Claudio; Villagran, Carolina

2005-07-01

291

Rain from Tropical Storm Noel  

NASA Technical Reports Server (NTRS)

Though not the most powerful storm of the 2007 Atlantic Hurricane season, Tropical Storm Noel was among the most deadly. Only Category 5 Hurricane Felix and its associated flooding had a higher toll. The slow-moving Tropical Storm Noel inundated the Dominican Republic, Haiti, Jamaica, Cuba, and the Bahamas with heavy rain between October 28 and November 1, 2007. The resulting floods and mudslides left at least 115 dead and thousands homeless throughout the Caribbean, reported the Associated Press on November 2, 2007. This image shows the distribution of the rainfall that made Noel a deadly storm. The image shows rainfall totals as measured by the Multi-satellite Precipitation Analysis (MPA) at NASA Goddard Space Flight Center from October 26 through November 1, 2007. The analysis is based on measurements taken by the Tropical Rainfall Measuring Mission (TRMM) satellite. The heaviest rainfall fell in the Dominican Republic and the Bahamas, northeast of Noel's center. Areas of dark red show that rainfall totals over the south-central Dominican Republic and parts of the Bahamas were over 551 millimeters (21 inches). Much of eastern Hispaniola, including both the Dominican Republic and Haiti received at least 200 mm (about 8 inches) of rain, shown in yellow. Rainfall totals over Haiti and Cuba were less, with a range of at least 50 mm (2 inches) to over 200 mm (8 inches).

2007-01-01

292

Current changes in tropical precipitation  

NASA Astrophysics Data System (ADS)

Current changes in tropical precipitation from satellite data and climate models are assessed. Wet and dry regions of the tropics are defined as the highest 30% and lowest 70% of monthly precipitation values. Observed tropical ocean trends in the wet regime (1.8%/decade) and the dry regions (-2.6%/decade) according to the Global Precipitation Climatology Project (GPCP) over the period including Special Sensor Microwave Imager (SSM/I) data (1988-2008), where GPCP is believed to be more reliable, are of smaller magnitude than when including the entire time series (1979-2008) and closer to model simulations than previous comparisons. Analysing changes in extreme precipitation using daily data within the wet regions, an increase in the frequency of the heaviest 6% of events with warming for the SSM/I observations and model ensemble mean is identified. The SSM/I data indicate an increased frequency of the heaviest events with warming, several times larger than the expected Clausius-Clapeyron scaling and at the upper limit of the substantial range in responses in the model simulations.

Allan, Richard P.; Soden, Brian J.; John, Viju O.; Ingram, William; Good, Peter

2010-04-01

293

Medical geochemistry of tropical environments  

NASA Astrophysics Data System (ADS)

Geochemically, tropical environments are unique. This uniqueness stems from the fact that these terrains are continuously subjected to extreme rainfall and drought with resulting strong geochemical fractionation of elements. This characteristic geochemical partitioning results in either severe depletion of elements or accumulation to toxic levels. In both these situations, the effect on plant, animal and human health is marked. Medical geochemistry involves the study of the relationships between the geochemistry of the environment in which we live and the health of the population living in this particular domain. Interestingly, the relationships between geochemistry and health are most marked in the tropical countries, which coincidentally are among the poorest in the world. The very heavy dependence on the immediate environment for sustainable living in these lands enables the medical geochemist to observe correlations between particular geochemical provinces and the incidence of certain diseases unique to these terrains. The aetiology of diseases such as dental and skeletal fluorosis, iodine deficiency disorders, diseases of humans and animals caused by mineral imbalances among others, lie clearly in the geochemical environment. The study of the chemistry of the soils, water and stream sediments in relation to the incidence of geographically distributed diseases in the tropics has not only opened up new frontiers in multidisciplinary research, but has offered new challenges to the medical profession to seriously focus attention on the emerging field of medical geochemistry with the collaboration of geochemists and epidemiologists.

Dissanayake, C. B.; Chandrajith, Rohana

1999-10-01

294

Diagnostic Research into the Tropical Atmosphere and the Role of Tropical Processes in the General Circulation.  

National Technical Information Service (NTIS)

The structure of tropical disturbances such as easterly waves, tropical cyclones, cyclonic and anticyclonic eddies in the upper trosposphere, squall lines, monsoon depressions, inter-tropospheric cyclones in the Asian monsoon, subtropical cyclones over th...

M. A. Petrossiants I. G. Sitnikov

1986-01-01

295

Rodents on pig and chicken farms - a potential threat to human and animal health  

PubMed Central

Rodents can cause major problems through spreading various diseases to animals and humans. The two main species of rodents most commonly found on farms around the world are the house mouse (Mus musculus) and the brown rat (Rattus norvegicus). Both species are omnivorous and can breed year-round under favourable conditions. This review describes the occurrence of pathogens in rodents on specialist pig and chicken farms, which are usually closed units with a high level of bio-security. However, wild rodents may be difficult to exclude completely, even from these sites, and can pose a risk of introducing and spreading pathogens. This article reviews current knowledge regarding rodents as a hazard for spreading disease on farms. Most literature available regards zoonotic pathogens, while the literature regarding pathogens that cause disease in farm animals is more limited.

Backhans, Annette; Fellstrom, Claes

2012-01-01

296

Occurrence of pathogens in wild rodents caught on Swedish pig and chicken farms.  

PubMed

A total of 207 wild rodents were caught on nine pig farms, five chicken farms and five non-farm locations in Sweden and surveyed for a selection of bacteria, parasites and viruses. Lawsonia intracellularia and pathogenic Yersinia enterocolitica were only detected in rodents on pig farms (9% and 8% prevalence, respectively) which indicate that these agents are more likely to be transmitted to rodents from pigs or the environment on infected farms. Brachyspira hyodysenteriae (1%), Brachyspira intermedia (2%), Campylobacter jejuni (4%), Campylobacter upsaliensis (2%), leptospires (7%) and encephalomyocarditis virus (9%) were also detected from rodents not in contact with farm animals. Giardia and Cryptosporidium spp. were common, although no zoonotic types were verified, and Salmonella enterica was isolated from 1/11 mice on one farm but not detected by PCR from any of the rodents. Trichinella spp. and Toxoplasma gondii were not detected. PMID:23174339

Backhans, A; Jacobson, M; Hansson, I; Lebbad, M; Lambertz, S Thisted; Gammelgård, E; Saager, M; Akande, O; Fellström, C

2013-09-01

297

Rodent communities in an exurbanizing southwestern landscape (U.S.A.).  

PubMed

Ranches are being converted to exurban housing developments in the southwestern United States, with potentially significant but little-studied impacts on biological diversity. We captured rodents on 48 traplines in grasslands, mesquite savannas, and oak savannas in southeastern Arizona that were grazed by livestock, embedded in exurban housing developments, grazed and embedded in development, or neither grazed nor embedded in development. Independent of habitat or development, rodent species richness, mean rank abundance, and capture rates of all rodents combined were negatively related to presence of livestock grazing or to its effects on vegetative ground cover Exurban development had no obvious effects on rodent variety or abundance. Results suggest southwester.n exurban developments can sustain a rich assemblage of grassland and savanna rodents if housing densities are low and houses are embedded in a matrix of natural vegetation with little grazing. PMID:16922240

Bock, Carl E; Jones, Zach E; Bock, Jane H

2006-08-01

298

Coxiella burnetii in Rodents on Heixiazi Island at the Sino-Russian Border  

PubMed Central

This work is a molecular epidemiologic study to detect the incidence of Coxiella burnetii in rodents on Heixiazi Island at the Sino-Russian border of Heilongjiang Province. Liver tissues were extracted and processed to test the incidence of C. burnetii infection using polymerase chain reaction analysis. In total, 18% (66 of 370) of rodents tested positive for infection. The results of logistic regression analysis indicated that infection with C. burnetii was associated significantly with weight and month of capture, and infection was found in all rodent species that were observed; there was no significant difference of sex on the infection of C. burnetii. Though phylogenetic analysis disclosed heterogeneity in the nucleotide sequences isolated from the island rodents, the majority of observed strains were among the most common strains found worldwide. This is the first report on the incidence of C. burnetii in rodents on Heixiazi Island at the Sino-Russian border.

Liu, Lijuan; Baoliang, Xu; Yingqun, Fu; Ming, Li; Yu, Yang; Yong, Hou; Shasha, Wang; Manxia, Hu; Tianyu, Guo; Chao, Jiang; Xiaohong, Sun; Jing, Wang

2013-01-01

299

Cell proliferation not associated with carcinogenesis in rodents and humans.  

PubMed Central

Cell proliferation has often been found to be associated with carcinogenesis in rodents and humans at different stages of the multistage carcinogenesis process. The multistage process includes initiation, promotion, and progression phases. At each phase, increasing the normal level of cell turnover of target cells may enhance carcinogenesis. However, we present evidence that normal levels of cell turnover, or increasing the rate of cell turnover at these different stages, do not necessarily lead to enhanced carcinogenesis. In normal tissues, the length of the cell cycle depends on the age of the host and varies from tissue to tissue. Tissues with normal short cell cycles, such as intestine and bone marrow, do not show a high rate of spontaneous tumors in most species. Cells with higher turnover should be more susceptible to carcinogens at the initiation stage of carcinogenesis if cell proliferation per se causes cancer and if these cells or their progeny survive. Cancer in humans is more often associated with specific etiological factors rather than with the natural proliferative rate of specific tissues. For many tissues of humans and rodents, age-related diseases develop in a progressive, irreversible manner. Often, naturally occurring chronic degenerative and inflammatory changes in a tissue (e.g., kidney, liver, heart, reproductive tract) lead to chronic regeneration of the damaged tissue. Yet, cancer is rarely found in these tissues. In rodent carcinogenesis experiments, chronic toxic lesions, accompanied by increases in normal levels of cell turnover, have sometimes been observed in target organs of nongenotoxic carcinogens. More often, however, organ-specific nongenotoxic toxins are not carcinogens. These toxins include compounds toxic for the liver, kidney, and nasal cavity. In 19 inhalation bioassays conducted by the National Toxicology Program, 5/5 nasal carcinogens and 12/14 nasal noncarcinogens caused nasal lesions usually associated with chronic cell proliferation. Although cell proliferation may contribute to multistage carcinogenesis, cell proliferation is not necessarily a tumor promoter or cocarcinogen. Images FIGURE 2. FIGURE 4. FIGURE 5. FIGURE 6. A FIGURE 6. B FIGURE 7.

Ward, J M; Uno, H; Kurata, Y; Weghorst, C M; Jang, J J

1993-01-01

300

In vivo microCT imaging of rodent cerebral vasculature  

PubMed Central

Computed tomography (CT) remains a critical diagnostic tool for evaluating patients with cerebrovascular disease, and the advent of specialized systems for imaging rodents has extended these techniques to small animal models of these diseases. We therefore have evaluated in vivo methods of imaging rat models of hemorrhagic stroke using a high resolution compact computed tomography (‘microCT’) system (FLEX(tm) X-O(tm), Gamma Medica-Ideas, Northridge, CA). For all in vivo studies, the head of the anesthetized rat was secured in a custom immobilization device for microCT imaging with 512 projections over 2 min at 60 kVp and 0.530 mA (Itube × t/rotation = 63.6 mAs). First, imaging without iodinated contrast was performed (a) to differentiate the effect of contrast agent in contrast-enhanced CT and (b) to examine the effectiveness of the immobilization device between two time points of CT acquisitions. Then, contrast-enhanced CT was performed with continuous administration of iopromide (300 mgI ml?1 at 1.2 ml min?1) to visualize aneurysms and other vascular formations in the carotid and cerebral arteries that may precede subarachnoid hemorrhage. The accuracy of registration between the noncontrast and contrast-enhanced CT images with the immobilization device was compared against the images aligned with normalized mutual information using FMRIB's linear image registration tool (FLIRT). Translations and rotations were examined between the FLIRT-aligned noncontrast CT image and the nonaligned noncontrast CT image. These two data sets demonstrated translational and rotational differences of less than 0.5 voxel (?85 ?m) and 0.5°, respectively. Noncontrast CT demonstrated a very small volume (0.1 ml) of femoral arterial blood introduced surgically into the rodent brain. Continuous administration of iopromide during the CT acquisition produced consistent vascular contrast in the reconstructed CT images. As a result, carotid arteries and major cerebral blood vessels were visible with contrast-enhanced CT, but not with noncontrast CT. In conclusion, the CT-compatible immobilization device was useful for in vivo microCT imaging of intracranial blood and of vascular structures within and immediately adjacent to the rodent brain. The microCT imaging technique is also compatible with continuous administration of a conventional iodinated contrast agent (e.g. iopromide) and therefore does not require specialized small animal specific contrast agent that has comparatively long in vivo residence time.

Seo, Youngho; Hashimoto, Tomoki; Nuki, Yoshitsugu; Hasegawa, Bruce H

2008-01-01

301

Tropical forest preservation using economic incentives  

SciTech Connect

The authors address the problem of deforestation of the tropical forests in terms of economic factors. They outline the global effects, such as hydrological and climatological changes, that apparently small scale deforestation has, when the forest is destroyed in many different places. The authors suggest that industrialized nations should offer economic incentives for tropical nations to save their forests, since all the world will suffer the effects of tropical deforestation.

Katzman, M.T. (Oak Ridge National Lab., TN (USA)); Cale, W.G. Jr. (Univ. of Pennsylvania, Indiana (USA))

1990-12-01

302

Solar and anthropogenic forcing of tropical hydrology  

Microsoft Academic Search

Holocene climate proxies suggest substantial correlations between tropical meteorology and solar variations, but these have thus far not been explained. Using a coupled ocean-atmosphere-composition model forced by sustained multi-decadal irradiance increases, we show that greater tropical temperatures alter the hydrologic cycle, enhancing the climatological precipitation maxima in the tropics while drying the subtropical subsidence regions. The shift is enhanced by

Drew T. Shindell; Greg Faluvegi; Ron L. Miller; Gavin A. Schmidt; James E. Hansen; Shan Sun

2006-01-01

303

Moist dynamical feedbacks in tropical climate sensitivity  

NASA Astrophysics Data System (ADS)

Climate variations in the tropics generally involve changes in the tropical deep convection zones. This implies that interactions among large-scale dynamics, small-scale moist convective elements, cloud-radiative effects and surface fluxes must be taken into account in understanding tropical climate sensitivity. Some headway has been made for theory of these interactions in tropical temperature and precipitation response in interannual variability based on intermediate complexity modeling. . The status of this will be reviewed with an eye to possible implications for the global warming case.

Neelin, J. D.; Su, H.; Chou, C.

2003-04-01

304

Interactions between climate and tropical cyclones  

NASA Astrophysics Data System (ADS)

For the last 50 years, there have been two major thrusts in tropical cyclone research: determining the state of the atmosphere and ocean that is suitable for the formation of tropical storms (the genesis criteria) and short-term forecasting of the track and intensity of storms. Efforts to forecast seasonal storm activity, especially in the North Atlantic Ocean, have been undertaken through empirical means and, more recently, using low-resolution climate models. Climate model results have been exceptionally encouraging suggesting that the tropical cyclogenesis factors are predictable and are part of the large scale tropical circulation. During the last few years, a spate of papers has noted the relationship between changes in sea-surface temperature (SST) and tropical cyclone intensity and frequency. A critical issue is determining to what degree the frequency of hurricanes, as well as their intensity distribution, will change in a warming world. We discuss recent research regarding the interactions of the climate system with tropical cyclones, including the role of climate in determining the genesis of tropical cyclones and the role of tropical cyclones in the heat balance of the planet. Specifically: (i) We re-examine the genesis criteria of tropical cyclones and add two new criteria based on the behavior of waves in a flow varying in longitude and the inertial instability of equatorial flow in a cross-equatorial pressure gradient environment. Tropical cyclones are seen to form where the stretching deformation is negative and where large-scale waves transform into tight smaller and highly energetic scale vortices. We also discuss the tendency for storms to develop and intensify where the near-equatorial flow is inertially unstable. (ii) Tropical cyclones act to cool the tropical oceans by > 1K/year by evaporation of ocean surface water and by entrainment mixing with cooler water from below the mixed layer. We suggest that tropical cyclones are important part of the heat budget of the planet and act as efficient ventilators of the tropical ocean, transporting heat polewards in both the ocean and the atmosphere. We discuss the mechanisms by which hurricanes efficiently transport mass and heat upwards and then polewards and how the vertically mixed heat in the oceans joins the annual cycle of ocean heat transport. We speculate that the near constancy of the global annual number of tropical cyclones is evidence that the heat transport of storms is governed by an integral constraint applying to the heat balance of the planet. With this information, we can speculate on the characteristics of tropical cyclones in a warmer world.

Webster, P. J.

2007-05-01

305

Tropical Tropospheric Temperature Variations Caused by ENSO and Their Influence on the Remote Tropical Climate  

Microsoft Academic Search

The warming of the entire tropical free troposphere in response to El Nino is well established, and suggests a tropical mechanism for the El Nino-Southern Oscillation (ENSO) teleconnection. The potential impact of this warming on remote tropical climates is examined through investigating the adjustment of a single-column model to imposed tropospheric temperature variations, assuming that ENSO controls interannual tropospheric temper-

John C. H. Chiang; Adam H. Sobel

2002-01-01

306

Multilocus Sequence Typing Implicates Rodents as the Main Reservoir Host of Human-Pathogenic Borrelia garinii in Japan?†  

PubMed Central

Multilocus sequence typing of Borrelia garinii isolates from humans and comparison with rodent and tick isolates were performed. Fifty-nine isolates were divided into two phylogenetic groups, and an association was detected between clinical and rodent isolates, suggesting that, in Japan, human-pathogenic B. garinii comes from rodents via ticks.

Takano, Ai; Nakao, Minoru; Masuzawa, Toshiyuki; Takada, Nobuhiro; Yano, Yasuhiro; Ishiguro, Fubito; Fujita, Hiromi; Ito, Takuya; Ma, Xiaohang; Oikawa, Yozaburo; Kawamori, Fumihiko; Kumagai, Kunihiko; Mikami, Toshiyuki; Hanaoka, Nozomu; Ando, Shuji; Honda, Naoko; Taylor, Kyle; Tsubota, Toshio; Konnai, Satoru; Watanabe, Haruo; Ohnishi, Makoto; Kawabata, Hiroki

2011-01-01

307

The Role of the Tropics in Abrupt Climate Changes  

SciTech Connect

Topics addressed include: abrupt climate changes and ocean circulation in the tropics; what controls the ocean thermal structure in the tropics; a permanent El Niño in paleoclimates; the energetics of the tropical ocean.

Fedorov, Alexey [Yale University] [Yale University

2013-12-07

308

Edible Leaves of the Tropics (2nd Edition).  

National Technical Information Service (NTIS)

Contents: The principal edible green leaf herbs of the tropics; Some fruits, vegetables, and ornamental plants that also bear edible leaves; Common weeds with edible green leaves; Tropical trees with edible green leaves; Tropical leaves as spices and teas...

F. W. Martin R. M. Ruberte

1979-01-01

309

Hojas Comestibles del Tropico (Edible Leaves of the Tropics).  

National Technical Information Service (NTIS)

Contents: The principal edible green leaf herbs of the tropics; Some fruits, vegetables, and ornamental plants that also bear edible leaves; Common weeds with edible green leaves; Tropical trees with edible green leaves; Tropical leaves as spices and teas...

F. W. Martin R. M. Ruberte

1975-01-01

310

Organizing and Managing Tropical Disease Control Programs. Case Studies.  

National Technical Information Service (NTIS)

Tropical disease remains a serious public health problem in developing countries. Without renewed global and national efforts to control tropical diseases, many people will suffer and die needlessly. The study of tropical disease control programs in Brazi...

B. H. Liese P. S. Sachdeva D. G. Cochrane

1992-01-01

311

Experimental Evidence for Reduced Rodent Diversity Causing Increased Hantavirus Prevalence  

PubMed Central

Emerging and re-emerging infectious diseases have become a major global environmental problem with important public health, economic, and political consequences. The etiologic agents of most emerging infectious diseases are zoonotic, and anthropogenic environmental changes that affect wildlife communities are increasingly implicated in disease emergence and spread. Although increased disease incidence has been correlated with biodiversity loss for several zoonoses, experimental tests in these systems are lacking. We manipulated small-mammal biodiversity by removing non-reservoir species in replicated field plots in Panama, where zoonotic hantaviruses are endemic. Both infection prevalence of hantaviruses in wild reservoir (rodent) populations and reservoir population density increased where small-mammal species diversity was reduced. Regardless of other variables that affect the prevalence of directly transmitted infections in natural communities, high biodiversity is important in reducing transmission of zoonotic pathogens among wildlife hosts. Our results have wide applications in both conservation biology and infectious disease management.

Suzan, Gerardo; Marce, Erika; Giermakowski, J. Tomasz; Mills, James N.; Ceballos, Gerardo; Ostfeld, Richard S.; Armien, Blas; Pascale, Juan M.; Yates, Terry L.

2009-01-01

312

Endrin versus 12-ketoendrin in birds and rodents  

USGS Publications Warehouse

British workers showed that in rats the endrin metabolite, 12-ketoendrin, was five times as toxic as endrin, was probably the ultimate cause of death, and was the main form of endrin in the brain at death. In cows and rabbits, however, they detected little of this metabolite. They found none in hens. We found no 12-ketoendrin in birds of four orders that had been heavily exposed to or killed by endrin. We suggest that residue work with birds need not consider this compound unless birds have been eating endrin-killed rodents. White mice had much less 12-ketoendrin than rats, but had more endrin. In tests with spiked samples, 12-ketoendrin was successfully recovered from extracts by gel permeation chromatography, but not by florisil.

Stickel, W.H.; Kaiser, T.E.; Reichel, W.L.

1979-01-01

313

Behavioral effects of developmental methylmercury drinking water exposure in rodents.  

PubMed

Early methylmercury (MeHg) exposure can have long-lasting consequences likely arising from impaired developmental processes, the outcome of which has been exposed in several longitudinal studies of affected populations. Given the large number of newborns at an increased risk of learning disabilities associated with in utero MeHg exposure, it is important to study neurobehavioral alterations using ecologically valid and physiologically relevant models. This review highlights the benefits of using the MeHg drinking water exposure paradigm and outlines behavioral outcomes arising from this procedure in rodents. Combination treatments that exacerbate or ameliorate MeHg-induced effects, and possible molecular mechanisms underlying behavioral impairment are also discussed. PMID:24210169

Bisen-Hersh, Emily B; Farina, Marcelo; Barbosa, Fernando; Rocha, Joao B T; Aschner, Michael

2014-04-01

314

Roles of dental development and adaptation in rodent evolution.  

PubMed

In paleontology, many changes affecting morphology, such as tooth shape in mammals, are interpreted as ecological adaptations that reflect important selective events. Despite continuing studies, the identification of the genetic bases and key ecological drivers of specific mammalian dental morphologies remains elusive. Here we focus on the genetic and functional bases of stephanodonty, a pattern characterized by longitudinal crests on molars that arose in parallel during the diversification of murine rodents. We find that overexpression of Eda or Edar is sufficient to produce the longitudinal crests defining stephanodonty in transgenic laboratory mice. Whereas our dental microwear analyses show that stephanodonty likely represents an adaptation to highly fibrous diet, the initial and parallel appearance of stephanodonty may have been facilitated by developmental processes, without being necessarily under positive selection. This study demonstrates how combining development and function can help to evaluate adaptive scenarios in the evolution of new morphologies. PMID:24051719

Rodrigues, Helder Gomes; Renaud, Sabrina; Charles, Cyril; Le Poul, Yann; Solé, Floréal; Aguilar, Jean-Pierre; Michaux, Jacques; Tafforeau, Paul; Headon, Denis; Jernvall, Jukka; Viriot, Laurent

2013-01-01

315

Swimming ability in three Costa Rican dry forest rodents.  

PubMed

We investigated the swimming abilities of three Costa Rican dry forest rodents (Coues' rice rat. Oryzomys couesi, hispid cotton rat, Sigmodon hispidus, and spiny pocket mouse, Liomys salvini) associated with a large marsh, Laguna Palo Verde, using 90 s swim trials in a plastic container. Swimming ability was evaluated by observing the use of limbs and tail in the water, inclination to the surface, and diving and floating behavior. Rice rats could float, swim and dive, suggesting that they can exploit surface and underwater resources. Cotton rats swam at the water's surface, but were less skilled swimmers than rice rats. Spiny pocket mice tired quickly and had difficulty staying at the water's surface. Results suggest that differential swimming ability is related to the distribution of the three sympatric species within the marsh and adjacent forest habitats. PMID:12189799

Cook, W M; Timm, R M; Hyman, D E

2001-01-01

316

?-Cell Generation: Can Rodent Studies Be Translated to Humans?  

PubMed Central

?-cell replacement by allogeneic islet transplantation is a promising approach for patients with type 1 diabetes, but the shortage of organ donors requires new sources of ? cells. Islet regeneration in vivo and generation of ?-cells ex vivo followed by transplantation represent attractive therapeutic alternatives to restore the ?-cell mass. In this paper, we discuss different postnatal cell types that have been envisaged as potential sources for future ?-cell replacement therapy. The ultimate goal being translation to the clinic, a particular attention is given to the discrepancies between findings from studies performed in rodents (both ex vivo on primary cells and in vivo on animal models), when compared with clinical data and studies performed on human cells.

Carlotti, Francoise; Zaldumbide, Arnaud; Ellenbroek, Johanne H.; Spijker, H. Siebe; Hoeben, Rob C.; de Koning, Eelco J.

2011-01-01

317

Melatonin inhibits proliferation and melanogenesis in rodent melanoma cells.  

PubMed

The effects of melatonin on proliferation and on the induction of melanogenesis in rodent melanoma cells were investigated. It was found that melatonin at low concentrations (0.1-10 nM) inhibited cell growth but had no effect on melanogenesis, while at high concentrations (> or = 0.1 microM) it inhibited the induction of melanogenesis but not cell growth. These effects were specific since corresponding concentrations of the direct precursor and product of melatonin degradation N-acetylserotonin (N-Ac-5HT) and 5-methoxytryptamine (5MT), respectively, did not have any effect on cell proliferation or melanogenesis. At very high concentration (100 microM) both N-Ac-5HT and melatonin could stimulate melanoma proliferation while 5MT inhibited it. The demonstration of differential and unparalleled effects of melatonin on cell proliferation and melanogenesis suggests that melatonin can regulate or modify both processes via different mechanisms. PMID:8500544

Slominski, A; Pruski, D

1993-06-01

318

Melanocortin control of energy balance: evidence from rodent models.  

PubMed

Regulation of energy balance is extremely complex, and involves multiple systems of hormones, neurotransmitters, receptors, and intracellular signals. As data have accumulated over the last two decades, the CNS melanocortin system is now identified as a prominent integrative network of energy balance controls in the mammalian brain. Here, we will review findings from rat and mouse models, which have provided an important framework in which to study melanocortin function. Perhaps most importantly, this review attempts for the first time to summarize recent advances in our understanding of the intracellular signaling pathways thought to mediate the action of melanocortin neurons and peptides in control of longterm energy balance. Special attention will be paid to the roles of MC4R/MC3R, as well as downstream neurotransmitters within forebrain and hindbrain structures that illustrate the distributed control of melanocortin signaling in energy balance. In addition, distinctions and controversy between rodent species will be discussed. PMID:21553232

De Jonghe, Bart C; Hayes, Matthew R; Bence, Kendra K

2011-08-01

319

Ljungan virus is endemic in rodents in the UK.  

PubMed

Ljungan virus is a recently identified member of the family Picornaviridae that was isolated from bank voles in Sweden. LjV has been associated with [corrected] type 1 diabetes-like symptoms and myocarditis in bank voles (Myodes glareolus), and it has been suggested that it has zoonotic potential. Here, we show for the first time that Ljungan virus is prevalent (20-27 % positive by PCR) in four species of UK rodent (Myodes glareolus [bank vole], Apodemus sylvaticus [wood mouse], Microtus agrestis [field vole] and Mus musculus [house mouse]). Sequence analysis showed that Ljungan virus of genotypes 1 and 2 were present, although genotype 1 was more prevalent and more frequently associated with brain tissue. This study highlights the prevalence of Ljungan virus in the UK and the need for assessment [corrected] of its zoonotic potential. PMID:23665770

Salisbury, Anne-Marie; Begon, Michael; Dove, Winifred; Niklasson, Bo; Stewart, James P

2014-03-01

320

Transmission of Guanarito and Pirital Viruses among Wild Rodents, Venezuela  

PubMed Central

Samples from rodents captured on a farm in Venezuela in February 1997 were tested for arenavirus, antibody against Guanarito virus (GTOV), and antibody against Pirital virus (PIRV). Thirty-one (48.4%) of 64 short-tailed cane mice (Zygodontomys brevicauda) were infected with GTOV, 1 Alston’s cotton rat (Sigmodon alstoni) was infected with GTOV, and 36 (64.3%) of 56 other Alston’s cotton rats were infected with PIRV. The results of analyses of field and laboratory data suggested that horizontal transmission is the dominant mode of GTOV transmission in Z. brevicauda mice and that vertical transmission is an important mode of PIRV transmission in S. alstoni rats. The results also suggested that bodily secretions and excretions from most GTOV-infected short-tailed cane mice and most PIRV-infected Alston’s cotton rats may transmit the viruses to humans.

Milazzo, Mary L.; Cajimat, Maria N.B.; Duno, Gloria; Duno, Freddy; Utrera, Antonio

2011-01-01

321

Melanocortin Control of Energy Balance: Evidence from Rodent Models  

PubMed Central

Regulation of energy balance is extremely complex, and involves multiple systems of hormones, neurotransmitters, receptors, and intracellular signals. As data have accumulated over the last two decades, the CNS melanocortin system is now identified as a prominent integrative network of energy balance controls in the mammalian brain. Here, we will review findings from rat and mouse models, which have provided an important framework in which to study melanocortin function. Perhaps most importantly, this review attempts for the first time to summarize recent advances in our understanding of the intracellular signaling pathways thought to mediate the action of melanocortin neurons and peptides in control of long term energy balance. Special attention will be paid to the roles of MC4R/MC3R, as well as downstream neurotransmitters within forebrain and hindbrain structures that illustrate the distributed control of melanocortin signaling in energy balance. In addition, distinctions and controversy between rodent species will be discussed.

De Jonghe, Bart C.; Hayes, Matthew R.; Bence, Kendra K.

2011-01-01

322

Identification of novel anelloviruses with broad diversity in UK rodents  

PubMed Central

Anelloviruses are a family of small circular ssDNA viruses with a vast genetic diversity. Human infections with the prototype anellovirus, torque teno virus (TTV), are ubiquitous and related viruses have been described in a number of other mammalian hosts. Despite over 15 years of investigation, there is still little known about the pathogenesis and possible disease associations of anellovirus infections, arising in part due to the lack of a robust cell culture system for viral replication or tractable small-animal model. We report the identification of diverse anelloviruses in several species of wild rodents. The viruses are highly prevalent in wood mice (Apodemus sylvaticus) and field voles (Microtus agrestis), detectable at a low frequency in bank voles (Myodes glareolus), but absent from house mice (Mus musculus). The viruses identified have a genomic organization consistent with other anelloviruses, but form two clear phylogenetic groups that are as distinct from each other as from defined genera.

Nishiyama, Shoko; Dutia, Bernadette M.; Stewart, James P.; Meredith, Anna L.; Shaw, Darren J.; Simmonds, Peter

2014-01-01

323

The socially stressed heart. Insights from studies in rodents.  

PubMed

The existence of a close relationship between psychosocial factors and cardiovascular morbidity is not just a hypothesis anymore. Research on humans has been attempting to unravel the significance of this association by investigating psychological and social characteristics in relation to cardiovascular health. However, this research is limited by the difficulty to control and standardize for the individual social history, the impossibility to apply psychosocial stress stimuli for mere experimental purposes, as well as the long time span of cardiovascular pathogenesis in humans. Animal studies controlling for social environment and adverse social episodes since weaning allow for partially overcoming these limitations. The aim of this review is to provide an up-to-date reference of the experimental evidence so far collected on the link between psychosocial factors and cardiovascular (dys-)function in rodent species, with special emphasis on social conflict, aggressiveness and negative mood states, which have been significantly associated with increased risk of cardiovascular disease. PMID:24373860

Sgoifo, Andrea; Carnevali, Luca; Grippo, Angela J

2014-02-01

324

Hepatoprotective Effect of Aged Black Garlic Extract in Rodents  

PubMed Central

In this study, we investigated the hepatoprotective effects of aged black garlic (ABG) in rodent models of liver injury. ABG inhibited carbon tetrachloride-induced elevation of aspartate transaminase (AST) and alanine transaminase (ALT), which are markers of hepatocellular damage, in SD rats. D-galactosamineinduced hepatocellular damage was also suppressed by ABG treatment. However, ABG does not affect the elevation of alkaline phosphatase (ALP), a marker of hepatobilliary damage, in rats treated with carbon tetrachloride or D-galactosamine. We also examined the effect of ABG on high-fat diet (HFD)-induced fatty liver and subsequent liver damage. ABG had no significant effect on body weight increase and plasma lipid profile in HFD-fed mice. However, HFD-induced increase in AST and ALT, but not ALP, was significantly suppressed by ABG treatment. These results demonstrate that ABG has hepatoprotective effects and suggest that ABG supplementation might be a good adjuvant therapy for the management of liver injury.

Lee, Chang Woo; Oh, Soo Jin; Yun, Jieun; Kang, Moo Rim; Han, Sang-Bae; Park, Heungsik; Jung, Jae Chul; Chung, Yoon Hoo; Kang, Jong Soon

2014-01-01

325

DNA barcoding of sigmodontine rodents: identifying wildlife reservoirs of zoonoses.  

PubMed

Species identification through DNA barcoding is a tool to be added to taxonomic procedures, once it has been validated. Applying barcoding techniques in public health would aid in the identification and correct delimitation of the distribution of rodents from the subfamily Sigmodontinae. These rodents are reservoirs of etiological agents of zoonoses including arenaviruses, hantaviruses, Chagas disease and leishmaniasis. In this study we compared distance-based and probabilistic phylogenetic inference methods to evaluate the performance of cytochrome c oxidase subunit I (COI) in sigmodontine identification. A total of 130 sequences from 21 field-trapped species (13 genera), mainly from southern Brazil, were generated and analyzed, together with 58 GenBank sequences (24 species; 10 genera). Preliminary analysis revealed a 9.5% rate of misidentifications in the field, mainly of juveniles, which were reclassified after examination of external morphological characters and chromosome numbers. Distance and model-based methods of tree reconstruction retrieved similar topologies and monophyly for most species. Kernel density estimation of the distance distribution showed a clear barcoding gap with overlapping of intraspecific and interspecific densities < 1% and 21 species with mean intraspecific distance < 2%. Five species that are reservoirs of hantaviruses could be identified through DNA barcodes. Additionally, we provide information for the description of a putative new species, as well as the first COI sequence of the recently described genus Drymoreomys. The data also indicated an expansion of the distribution of Calomys tener. We emphasize that DNA barcoding should be used in combination with other taxonomic and systematic procedures in an integrative framework and based on properly identified museum collections, to improve identification procedures, especially in epidemiological surveillance and ecological assessments. PMID:24244670

Müller, Lívia; Gonçalves, Gislene L; Cordeiro-Estrela, Pedro; Marinho, Jorge R; Althoff, Sérgio L; Testoni, André F; González, Enrique M; Freitas, Thales R O

2013-01-01

326

Distribution of oxytocin in the brain of a eusocial rodent.  

PubMed

Naked mole-rats are highly social rodents that live in large colonies characterized by a rigid social and reproductive hierarchy. Only one female, the queen, breeds. Most colony members are non-reproductive subordinates that work cooperatively to rear the young and maintain an underground burrow system. Little is known about the neurobiological basis of the complex sociality exhibited by this species. The neuropeptide oxytocin (Oxt) modulates social bonding and other social behaviors in many vertebrates. Here we examined the distribution of Oxt immunoreactivity in the brains of male and female naked mole-rats. As in other species, the majority of Oxt-immunoreactive (Oxt-ir) cells were found in the paraventricular and supraoptic nuclei, with additional labeled cells scattered throughout the preoptic and anterior hypothalamic areas. Oxt-ir fibers were found traveling toward and through the median eminence, as well as in the tenia tecta, septum, and nucleus of the diagonal band of Broca. A moderate network of fibers covered the bed nucleus of the stria terminalis and preoptic area, and a particularly dense fiber innervation of the nucleus accumbens and substantia innominata was observed. In the brainstem, Oxt-ir fibers were found in the periaqueductal gray, locus coeruleus, parabrachial nucleus, nucleus of the solitary tract, and nucleus ambiguus. The high levels of Oxt immunoreactivity in the nucleus accumbens and preoptic area are intriguing, given the link in other rodents between Oxt signaling in these regions and maternal behavior. Although only the queen gives birth or nurses pups in a naked mole-rat colony, most individuals actively participate in pup care. PMID:18582538

Rosen, G J; de Vries, G J; Goldman, S L; Goldman, B D; Forger, N G

2008-08-26

327

Arctic Small Rodents Have Diverse Diets and Flexible Food Selection  

PubMed Central

The ecology of small rodent food selection is poorly understood, as mammalian herbivore food selection theory has mainly been developed by studying ungulates. Especially, the effect of food availability on food selection in natural habitats where a range of food items are available is unknown. We studied diets and selectivity of grey-sided voles (Myodes rufocanus) and tundra voles (Microtus oeconomus), key herbivores in European tundra ecosystems, using DNA metabarcoding, a novel method enabling taxonomically detailed diet studies. In order to cover the range of food availabilities present in the wild, we employed a large-scale study design for sampling data on food availability and vole diets. Both vole species had ingested a range of plant species and selected particularly forbs and grasses. Grey-sided voles also selected ericoid shrubs and tundra voles willows. Availability of a food item rarely affected its utilization directly, although seasonal changes of diets and selection suggest that these are positively correlated with availability. Moreover, diets and selectivity were affected by availability of alternative food items. These results show that the focal sub-arctic voles have diverse diets and flexible food preferences and rarely compensate low availability of a food item with increased searching effort. Diet diversity itself is likely to be an important trait and has previously been underrated owing to methodological constraints. We suggest that the roles of alternative food item availability and search time limitations for small rodent feeding ecology should be investigated. Nomenclature Annotated Checklist of the Panarctic Flora (PAF), Vascular plants. Available at: http://nhm2.uio.no/paf/, accessed 15.6.2012.

Soininen, Eeva M.; Ravolainen, Virve T.; Brathen, Kari Anne; Yoccoz, Nigel G.; Gielly, Ludovic; Ims, Rolf A.

2013-01-01

328

Survey of studies on how spaceflight affects rodent skeletal muscle.  

PubMed

Rodent muscles have been examined in more than 89 spaceflight studies over the last 25 years with much variation in the procedures and results. Mission duration ranged from four days to three weeks, postflight data collection ranged from a few hours to two days after landing, and there is great diversity in the number, size, and age of the rats that have flown. Several different types and sizes of animal enclosures have also been used--a significant factor because cage design affects animal activity and muscle loading. Only a small percentage (approximately 16%) of the total number of striated muscles in the rat have been examined. We have identified both substantial redundancy and inconsistencies in the results from studies to date. However, many of these appear unavoidable due to the great variation in experimental protocol of the different missions. Nevertheless these studies repeatedly confirm that exposure to spaceflight decreases the mass of limb muscles and leads to muscle atrophy. The majority of missions were flown by the former Soviet Union, but the majority of papers have been published by U.S. researchers. A relatively small number of investigators (about 50) clustered into fewer than 15 identifiable research groups worldwide account for most of the results to date. These groups have had access to rodent muscle tissue from two to seven spaceflights each. International cooperation in the post-cold war era and the publication of future work in peer-reviewed international journals should help greatly in reducing redundancy and enriching our knowledge of how gravity affects biological systems. PMID:10660771

Fejtek, M B; Wassersug, R J

1999-01-01

329

Simultaneous FMRI and electrophysiology in the rodent brain.  

PubMed

To examine the neural basis of the blood oxygenation level dependent (BOLD) magnetic resonance imaging (MRI) signal, we have developed a rodent model in which functional MRI data and in vivo intracortical recording can be performed simultaneously. The combination of MRI and electrical recording is technically challenging because the electrodes used for recording distort the MRI images and the MRI acquisition induces noise in the electrical recording. To minimize the mutual interference of the two modalities, glass microelectrodes were used rather than metal and a noise removal algorithm was implemented for the electrophysiology data. In our studies, two microelectrodes were separately implanted in bilateral primary somatosensory cortices (SI) of the rat and fixed in place. One coronal slice covering the electrode tips was selected for functional MRI. Electrode shafts and fixation positions were not included in the image slice to avoid imaging artifacts. The removed scalp was replaced with toothpaste to reduce susceptibility mismatch and prevent Gibbs ringing artifacts in the images. The artifact structure induced in the electrical recordings by the rapidly-switching magnetic fields during image acquisition was characterized by averaging all cycles of scans for each run. The noise structure during imaging was then subtracted from original recordings. The denoised time courses were then used for further analysis in combination with the fMRI data. As an example, the simultaneous acquisition was used to determine the relationship between spontaneous fMRI BOLD signals and band-limited intracortical electrical activity. Simultaneous fMRI and electrophysiological recording in the rodent will provide a platform for many exciting applications in neuroscience in addition to elucidating the relationship between the fMRI BOLD signal and neuronal activity. PMID:20811324

Pan, Wen-ju; Thompson, Garth; Magnuson, Matthew; Majeed, Waqas; Jaeger, Dieter; Keilholz, Shella

2010-01-01

330

Simultaneous fMRI and Electrophysiology in the Rodent Brain  

PubMed Central

To examine the neural basis of the blood oxygenation level dependent (BOLD) magnetic resonance imaging (MRI) signal, we have developed a rodent model in which functional MRI data and in vivo intracortical recording can be performed simultaneously. The combination of MRI and electrical recording is technically challenging because the electrodes used for recording distort the MRI images and the MRI acquisition induces noise in the electrical recording. To minimize the mutual interference of the two modalities, glass microelectrodes were used rather than metal and a noise removal algorithm was implemented for the electrophysiology data. In our studies, two microelectrodes were separately implanted in bilateral primary somatosensory cortices (SI) of the rat and fixed in place. One coronal slice covering the electrode tips was selected for functional MRI. Electrode shafts and fixation positions were not included in the image slice to avoid imaging artifacts. The removed scalp was replaced with toothpaste to reduce susceptibility mismatch and prevent Gibbs ringing artifacts in the images. The artifact structure induced in the electrical recordings by the rapidly-switching magnetic fields during image acquisition was characterized by averaging all cycles of scans for each run. The noise structure during imaging was then subtracted from original recordings. The denoised time courses were then used for further analysis in combination with the fMRI data. As an example, the simultaneous acquisition was used to determine the relationship between spontaneous fMRI BOLD signals and band-limited intracortical electrical activity. Simultaneous fMRI and electrophysiological recording in the rodent will provide a platform for many exciting applications in neuroscience in addition to elucidating the relationship between the fMRI BOLD signal and neuronal activity.

Pan, Wen-ju; Thompson, Garth; Magnuson, Matthew; Majeed, Waqas; Jaeger, Dieter; Keilholz, Shella

2010-01-01

331

Pulmonary Toxicity Studies of Lunar Dusts in Rodents  

NASA Technical Reports Server (NTRS)

NASA will build an outpost on the lunar surface for long-duration human habitation and research. The surface of the Moon is covered by a layer of fine, reactive dust, and the living quarters in the lunar outpost are expected to be contaminated by lunar dust. Because the toxicity of lunar dust is not known, NASA has tasked its toxicology laboratory to evaluate the risk of exposure to the dust and to establish safe exposure limits for astronauts working in the lunar habitat. Studies of the pulmonary toxicity of a dust are generally done first in rodents by intratracheal/intrapharyngeal instillation. This toxicity screening test is then followed by an inhalation study, which requires much more of the test dust and is labor intensive. Preliminary results obtained by examining lung lavage fluid from dust-treated mice show that lunar dust was somewhat toxic (more toxic than TiO2, but less than quartz dust). More extensive studies are in progress to further examine lung lavage fluid for biomarkers of toxicity and lung tissues for histopathological lesions in rodents exposed to aged and activated (ground) lunar dust samples. In these studies, reference dusts (TiO2 and quartz) of known toxicities and have industrial exposure limits will be studied in parallel so the relative toxicity of lunar dust can be determined. The results from the instillation studies will be useful for choosing exposure concentrations for the animal inhalation study. The animal inhalation exposure will be conducted with lunar dust simulant prior to the study with the lunar dust. The experiment with the simulate will ensure that the study techniques used with actual lunar dust will be successful. The results of instillation and inhalation studies will reveal the toxicological risk of exposures and are essential for setting exposure limits on lunar dust for astronauts living in the lunar habitat.

Lam, Chiu-wing; James, John T.

2009-01-01

332

Osseointegration of biochemically modified implants in an osteoporosis rodent model.  

PubMed

The present study examined the impact of implant surface modifications on osseointegration in an osteoporotic rodent model. Sandblasted, acid-etched titanium implants were either used directly (control) or were further modified by surface conditioning with NaOH or by coating with one of the following active agents: collagen/chondroitin sulphate, simvastatin, or zoledronic acid. Control and modified implants were inserted into the proximal tibia of aged ovariectomised (OVX) osteoporotic rats (n = 32/group). In addition, aged oestrogen competent animals received either control or NaOH conditioned implants. Animals were sacrificed 2 and 4 weeks post-implantation. The excised tibiae were utilised for biomechanical and morphometric readouts (n = 8/group/readout). Biomechanical testing revealed at both time points dramatically reduced osseointegration in the tibia of oestrogen deprived osteoporotic animals compared to intact controls irrespective of NaOH exposure. Consistently, histomorphometric and microCT analyses demonstrated diminished bone-implant contact (BIC), peri-implant bone area (BA), bone volume/tissue volume (BV/TV) and bone-mineral density (BMD) in OVX animals. Surface coating with collagen/chondroitin sulphate had no detectable impact on osseointegration. Interestingly, statin coating resulted in a transient increase in BIC 2 weeks post-implantation; which, however, did not correspond to improvement of biomechanical readouts. Local exposure to zoledronic acid increased BIC, BA, BV/TV and BMD at 4 weeks. Yet this translated only into a non-significant improvement of biomechanical properties. In conclusion, this study presents a rodent model mimicking severely osteoporotic bone. Contrary to the other bioactive agents, locally released zoledronic acid had a positive impact on osseointegration albeit to a lesser extent than reported in less challenging models. PMID:23832686

Stadlinger, B; Korn, P; Tödtmann, N; Eckelt, U; Range, U; Bürki, A; Ferguson, S J; Kramer, I; Kautz, A; Schnabelrauch, M; Kneissel, M; Schlottig, F

2013-01-01

333

Differentiation in seed hoarding among three sympatric rodent species in a warm temperate forest.  

PubMed

Although seed hoarding by rodents has been extensively studied, differentiation in seed-hoarding behaviors among sympatric rodent species has not been well investigated. Using semi-natural enclosures, we demonstrated that three sympatric rodent species showed clear differentiation in food selection, scatter versus larder hoarding behaviors and eating behaviors when offered seeds of four plant species from a warm temperate forest in northern China. The large field mouse Apodemus peninsulae preferred seeds of wild apricot (Prunus armeniaca) and Liaodong oak (Quercus liaotungensis), whereas the Chinese white-bellied rat Niviventor confucianus preferred seeds of cultivated walnut and Liaodong oak, and the David's rock squirrel Sciurotamias davidianus preferred seeds of cultivated walnut, wild apricot and Liaodong oak. All three rodents showed larder hoarding of seeds from all four plant species, but the large field mouse showed scatter hoarding of wild apricot, and the David's rock squirrel showed scatter hoarding of Liaodong oak and wild walnut. Acorns of Liaodong oak, which have a soft seed hull, were more often eaten in situ, whereas wild walnuts, which have a hard seed hull and more tannin, were less hoarded by all rodent species. Differentiation in the scatter versus larder hoarding behaviors of sympatric rodent species suggests that sympatric rodents play different roles in the regeneration of different sympatric plant species. PMID:21396061

Lu, Jiqi; Zhang, Zhibin

2008-06-01

334

Tropical geometry of statistical models  

PubMed Central

This article presents a unified mathematical framework for inference in graphical models, building on the observation that graphical models are algebraic varieties. From this geometric viewpoint, observations generated from a model are coordinates of a point in the variety, and the sum-product algorithm is an efficient tool for evaluating specific coordinates. Here, we address the question of how the solutions to various inference problems depend on the model parameters. The proposed answer is expressed in terms of tropical algebraic geometry. The Newton polytope of a statistical model plays a key role. Our results are applied to the hidden Markov model and the general Markov model on a binary tree.

Pachter, Lior; Sturmfels, Bernd

2004-01-01

335

Camera trapping: a contemporary approach to monitoring invasive rodents in high conservation priority ecosystems.  

PubMed

Invasive rodent species have established on 80% of the world's islands causing significant damage to island environments. Insular ecosystems support proportionally more biodiversity than comparative mainland areas, highlighting them as critical for global biodiversity conservation. Few techniques currently exist to adequately detect, with high confidence, species that are trap-adverse such as the black rat, Rattus rattus, in high conservation priority areas where multiple non-target species persist. This study investigates the effectiveness of camera trapping for monitoring invasive rodents in high conservation areas, and the influence of habitat features and density of colonial-nesting seabirds on rodent relative activity levels to provide insights into their potential impacts. A total of 276 camera sites were established and left in situ for 8 days. Identified species were recorded in discrete 15 min intervals, referred to as 'events'. In total, 19 804 events were recorded. From these, 31 species were identified comprising 25 native species and six introduced. Two introduced rodent species were detected: the black rat (90% of sites), and house mouse Mus musculus (56% of sites). Rodent activity of both black rats and house mice were positively associated with the structural density of habitats. Density of seabird burrows was not strongly associated with relative activity levels of rodents, yet rodents were still present in these areas. Camera trapping enabled a large number of rodents to be detected with confidence in site-specific absences and high resolution to quantify relative activity levels. This method enables detection of multiple species simultaneously with low impact (for both target and non-target individuals); an ideal strategy for monitoring trap-adverse invasive rodents in high conservation areas. PMID:24599307

Rendall, Anthony R; Sutherland, Duncan R; Cooke, Raylene; White, John

2014-01-01

336

Rabies in rodents and lagomorphs in the United States, 1995-2010.  

PubMed

Objective-To assess the epidemiology of rabies in rodents and lagomorphs and provide information that will enable public health officials to make recommendations regarding postexposure prophylaxis for humans after contact with these animals. Design-Cross-sectional epidemiological analysis. Sample-Rodents and lagomorphs submitted to state laboratories for rabies diagnosis from 1995 through 2010. Procedures-Positive samples were identified by use of direct fluorescent antibody testing, typed by sequencing of viral genes, and quantified via titration in mice or cell culture. Results-737 rabid rodents and lagomorphs were reported from 1995 through 2010, which represented a 62.3% increase, compared with the number of rabid rodents and lagomorphs reported from 1979 through 1994. The most commonly reported rodents or lagomorphs were groundhogs (Marmota monax). All animals submitted to the CDC for additional viral characterization were positive for the raccoon rabies virus variant. Infectious virus or viral RNA was detected in salivary glands or oral cavity tissues in 11 of 13 rabid rodents. Conclusions and Clinical Relevance-The increase in reported rabid rodents, compared with results of previous studies, appeared to be associated with spillover infections from the raccoon rabies epizootic during the first half of the study period. Analysis supported the assumption that rabies remained rare in rodents and lagomorphs. However, transmission of rabies virus via exposure to a rabid rodent or lagomorph may be possible. Given the rarity of rabies in these species, diagnostic testing and consideration of postexposure prophylaxis for humans with potential exposures should be considered on a case-by-case basis. PMID:25029313

Fitzpatrick, Jill L; Dyer, Jessie L; Blanton, Jesse D; Kuzmin, Ivan V; Rupprecht, Charles E

2014-08-01

337

Tropical Rainfall Measuring Mission (TRMM) Progress Report.  

National Technical Information Service (NTIS)

Recognizing the importance of rain in the tropics and the accompanying latent heat release, NASA for the U.S. and NASDA for Japan have partnered in the design, construction and flight of an Earth Probe satellite to measure tropical rainfall and calculate ...

J. Simpson R. Meneghini C. D. Kummerow R. Meneghini A. Hou R. F. Adler G. Huffman B. Barkstrom B. Wielicki S. Goodman

1999-01-01

338

Oceanic bromoform sources for the tropical atmosphere  

Microsoft Academic Search

Oceanic bromoform (CHBr3) is the major source of organic Br to the atmosphere and may be significant for ozone depletion through the contribution of reactive bromine to the upper troposphere and lower stratosphere of the midlatitudes and tropics. We report the first analyses of boundary layer air, surface and deep ocean waters from the tropical Atlantic. The data provide evidence

B. Quack; E. Atlas; G. Petrick; V. Stroud; S. Schauffler; D. W. R. Wallace

2004-01-01

339

Tropical deforestation and atmospheric carbon dioxide  

Microsoft Academic Search

Recent estimates of the net release of carbon to the atmosphere from deforestation in the tropics have ranged between 0.4 and 2.5 × 1015 g yr-1. Two things have happened to require a revision of these estimates. First, refinements of the methods used to estimate the stocks of carbon in the vegetation of tropical forests have produced new estimates that

R. A. Houghton

1991-01-01

340

TROPICAL MASS EXTINCTIONS AND THE SCIENTIFIC METHOD  

EPA Science Inventory

Kangas (1992), Undiscovered species and the falsifiability of the tropical mass extinction hypotheses, ESA Bulletin 73:124-125, 1992, argues that there is a paradox concerning the mass extinctions projected from current rates of tropical deforestation. he parameters; for a given ...

341

Global climate change and tropical ecosystems  

SciTech Connect

This book presents data on carbon pool fluxes from case studies in 12 countries in tropical regions. The chapters cover: Characteristics of tropical ecosystems; Soil and biotic carbon pools; Impacts of land use and soil management; Slash-and-burn practices; and Crop residue and fertility management.

Lal, R.; Eswaran, H.; Kimble, J.M.; Stewart, B.A. [eds.

2000-07-01

342

The tropical analogue of polar cones  

Microsoft Academic Search

We study the max-plus or tropical analogue of the notion of polar: the polar of a cone represents the set of linear inequalities satisfied by its elements. We establish an analogue of the bipolar theorem, which characterizes all the inequalities satisfied by the elements of a tropical convex cone. We derive this characterization from a new separation theorem. We also

Stéphane Gaubert; Ricardo D. Katz

2009-01-01

343

Satellite detection of tropical burning in Brazil  

Microsoft Academic Search

Tropical burning often occurs in remote areas of the world. Satellite remote sensing is the only practical solution for detecting and monitoring this burning. In this paper we demonstrate the capability of the Advanced Very High Resolution Radiometer onboard the National Oceanic and Atmospheric Administration polar orbiting satellites for detecting tropical fire activity in the Manaus, Brazil area.

Michael Matson; Brent Holben

1987-01-01

344

New Stable Isotope Tropical Paleoclimate Proxies  

Microsoft Academic Search

Organized tropical rain systems such as tropical cyclones (TC) and mesoscale convective systems (MCS) produce both water vapor and rainfall with distinctly low isotope ratios. This lowering is caused by recyling of water in organized systems. Therefore, fresh water carbonate organisms have considerable potential to act as proxy recorders of these systems. Ostracoda are ephemeral making them especially attractive candidates.

J. R. Lawrence

2005-01-01

345

Priorities for Biodiversity Conservation in the Tropics  

NSDL National Science Digital Library

Biodiversity Bulletin No 1, from the World Conservation Monitoring Centre is now online and is entitled "Priorities for Biodiversity Conservation in the Tropics,"by Michael Green and others. The bulletin provides an assessment of "the extent to which habitats in the tropics are protected and guidance on prioritising conservation action from global and national perspectives."

Bunting, Gillian C.; Green, Michael J.; Murray, Martyn G.; Paine, James R.

1998-01-01

346

Fire in Tropical Forests and Grasslands.  

National Technical Information Service (NTIS)

Fire in the tropics has a long history in which frequent wide-spread burning has profoundly altered physical and cultural environments. A vast and diverse literature pertaining to fire and its effects in tropical forests and grasslands was evaluated, clas...

R. B. Batchelder H. F. Hirt

1966-01-01

347

Innovative lead discovery strategies for tropical diseases  

Microsoft Academic Search

Lead discovery is currently a key bottleneck in the pipeline for much-needed novel drugs for tropical diseases such as malaria, tuberculosis, African sleeping sickness, leishmaniasis and Chagas disease. Here, we discuss the different approaches to lead discovery for tropical diseases and emphasize a coordination strategy that involves highly integrated partnerships and networks between scientists in academic institutions and industry in

Alan Hudson; Solomon Nwaka

2006-01-01

348

Current review of in vivo GBM rodent models: emphasis on the CNS-1 tumour model  

PubMed Central

GBM (glioblastoma multiforme) is a highly aggressive brain tumour with very poor prognosis despite multi-modalities of treatment. Furthermore, recent failure of targeted therapy for these tumours highlights the need of appropriate rodent models for preclinical studies. In this review, we highlight the most commonly used rodent models (U251, U86, GL261, C6, 9L and CNS-1) with a focus on the pathological and genetic similarities to the human disease. We end with a comprehensive review of the CNS-1 rodent model.

Jacobs, Valerie L; Valdes, Pablo A; Hickey, William F; De Leo, Joyce A

2011-01-01

349

Bridges to sustainable tropical health  

PubMed Central

Ensuring sustainable health in the tropics will require bridge building between communities that currently have a limited track record of interaction. It will also require new organizational innovation if much of the negative health consequences of large-scale economic development projects are to be equitably mitigated, if not prevented. We focus attention on three specific contexts: (i) forging linkages between the engineering and health communities to implement clean water and sanitation on a broad scale to prevent reworming, after the current deworming-only programs, of people by diverse intestinal parasites; (ii) building integrated human and animal disease surveillance infrastructure and technical capacity in tropical countries on the reporting and scientific evidence requirements of the sanitary and phytosanitary agreement under the World Trade Organization; and (iii) developing an independent and equitable organizational structure for health impact assessments as well as monitoring and mitigation of health consequences of economic development projects. Effective global disease surveillance and timely early warning of new outbreaks will require a far closer integration of veterinary and human medicine than heretofore. Many of the necessary surveillance components exist within separate animal- and human-oriented organizations. The challenge is to build the necessary bridges between them.

Singer, Burton H.; de Castro, Marcia Caldas

2007-01-01

350

Tropical Rainfall Measuring Mission (TRMM)  

NSDL National Science Digital Library

The Tropical Rainfall Measuring Mission (TRMM) satellite is a joint mission between NASA and the National Space Development Agency (NSDA) of Japan. It is designed to monitor and study tropical rainfall and the associated release of energy that helps to power the global water cycle. The satellite can greatly enhance our understanding of the interactions which produce changes in global rainfall and climate. A detailed overview of TRMM covers why we need TRMM, which is broken into grade-specific explanations; questions and answers about TRMM; TRMM instruments; climate-related facts; the Mission to Planet Earth "Education" Homepage; and case studies comparing land and ocean storms. Images showing current conditions, as well as archived images, movies, and animations are provided on hurricanes, global datasets covering lightning, temperature, and rainfall, monthly mean rainrates from 1998 through 2000, monthly rainfall anomalies, data types and idealized data simulations. Also archived are press releases, refereed journals, and scientific documents related to TRMM data information. An Educational Resources section provides teacher's guides, animations and activities on topics such as latent heat of evaporation and the water cycle, hurricanes as heat engines, air pressure systems in the context of El Nino/La Nina, lightning formation and the role of ice in a thunderstorm, and remote sensing of precipitation. The ground-based validation efforts of the TRMM are outlined in detail. Related organizations, data sources, field experiments, and TRMM research are linked from this site.

351

Chemical-induced atrial thrombosis in NTP rodent studies.  

PubMed

Cardiac thrombosis, one of the causes of sudden death throughout the world, plays a principal role in several cardiovascular diseases, such as myocardial infarction and stroke in humans. Data from studies of induction of chemical thrombosis in rodents help to identify substances in our environment that may contribute to cardiac thrombosis. Results for more than 500 chemicals tested in rodents in 2-year bioassays have been published as Technical Reports of the National Toxicology Program (NTP) http://ntp-server.niehs.nih.gov/index. We evaluated atrial thrombosis induced by these chemical exposures and compared it to similarly induced lesions reported in the literature. Spontaneous rates of cardiac thrombosis were determined for control Fischer 344 rats and B6C3F1 mice: 0% in rats and mice in 90-day studies and, in 2-year studies, 0.7% in both genders of mice, 4% in male rats, and 1% in female rats. Incidences of atrial thrombosis were increased in high-dosed groups involving 13 compounds (incidence rate: 20-100%): 2-butoxyethanol, C.I. Direct Blue 15, bis(2-chloroethoxy)methane, diazoaminobenzene, diethanolamine, 3,3'-dimethoxybenzidine dihydrochloride, hexachloroethane, isobutene, methyleugenol, oxazepam, C.I. Pigment Red 23, C.I. Acid Red 114, and 4,4'-thiobis(6-t-butyl-m-cresol). The main localization of spontaneously occurring and chemically induced thromboses occurred in the left atrium. The literature survey suggested that chemical-induced atrial thrombosis might be closely related to myocardial injury, endothelial injury, circulatory stasis, hypercoagulability, and impaired atrial mechanical activity, such as atrial fibrillation, which could cause stasis of blood within the left atrial appendage, contributing to left atrial thrombosis. Supplementary data referenced in this paper are not printed in this issue of Toxicologic Pathology. They are available as downloadable files at http://taylorandfrancis.metapress.com/openurl.asp?genre=journal&issn=0192-6233. To access them, click on the issue link for 33(5), then select this article. A download option appears at the bottom of this abstract. In order to access the full article online, you must either have an individual subscription or a member subscription accessed through www.toxpath.org. PMID:16048847

Yoshizawa, Katsuhiko; Kissling, Grace E; Johnson, Jo Anne; Clayton, Natasha P; Flagler, Norris D; Nyska, Abraham

2005-01-01

352

Factors influencing repeated seed movements by scatter-hoarding rodents in an alpine forest.  

PubMed

Scatter-hoarding rodents are effective dispersal agents for many plant species. Several studies have shown that rodents repeatedly re-cache seeds. The re-caching process often has a significant impact on final seedling establishment, but the factors determining its occurrence are poorly understood. In this study, we followed the fate of 3564 artificial seeds that varied in size, nutrient content and tannin content. Seeds cached closer to their original releasing plots were more likely to be re-cached, and to a further distance. Larger seeds were more likely to be re-cached than smaller ones, while nutrient and tannin content had little effect. Most plant species that depend on scatter-hoarding rodents for seed dispersal bear relatively large seeds, and large seeds are usually more likely to be dispersed and to establish seedlings, suggesting that the caching preferences of scatter-hoarding rodents may have played an important role in the evolution of large seeds. PMID:24759374

Wang, Bo; Chen, Jin; Corlett, Richard T

2014-01-01

353

Leishmania species: Detection and identification by nested PCR assay from skin samples of rodent reservoirs  

PubMed Central

Many rodent species act as reservoir hosts of zoonotic cutaneous leishmaniasis in endemic areas. In the present study a simple and reliable assay based on nested PCR was developed for the detection and identification of Leishmania parasites from rodent skin samples. We designed Leishmania-specific primers that successfully amplified ITS regions of Leishmania major, Leishmania gerbilli and Leishmania turanica using nested PCR. Out of 95 field collected Rhombomys opimus, 21 were positive by microscopic examination and 48 by nested PCR. The percentage of gerbils infected with L. major, L. gerbilli and L. turanica was 3.2%, 1.1% and 27.4%, respectively. In 15.8% of the rodents, we found mixed natural infections by L. major and L. turanica, 1.1% by L. major and L. gerbilli, and 2.1% by the three species. We concluded that this method is simple and reliable for detecting and identifying Leishmania species circulating in rodent populations.

Akhavan, Amir Ahmad; Mirhendi, Hossein; Khamesipour, Ali; Alimohammadian, Mohammad Hossein; Rassi, Yavar; Bates, Paul; Kamhawi, Shaden; Valenzuela, Jesus G.; Arandian, Mohammad Hossein; Abdoli, Hamid; Jalali-zand, Niloufar; Jafari, Reza; Shareghi, Niloufar; Ghanei, Maryam; Yaghoobi-Ershadi, Mohammad Reza

2010-01-01

354

Verification of natural infection of peridomestic rodents by PCV2 on commercial swine farms.  

PubMed

The porcine circovirus-2 (PCV2) is the main agent responsible for porcine circovirus associated diseases (PCVAD). Few studies have been done regarding PCV2 infection in other species. The purpose of this study was to investigate the occurrence of PCV2 infection in the peridomestic rodent species Mus musculus and Rattus rattus on commercial pig farms in Brazil. Immunohistochemistry assay demonstrated PCV2 in the spleen, lung and kidney. Viral DNA was detected in tissues by nested PCR assay. Partial sequences of PCV2 genomes detected in the rodents had strong identity with gene sequences of PCV2 isolates from pigs. These results show that the studied peridomestic rodent species can be naturally infected by PCV2. However, further studies are needed to confirm PCV2 transmission from rodents to pigs. PMID:23141170

Pinheiro, Albanno Leonard Braz Campos; Bulos, Luiz Henrique Silva; Onofre, Thiago Souza; de Paula Gabardo, Michelle; de Carvalho, Otávio Valério; Fausto, Mariana Costa; Guedes, Roberto Maurício Carvalho; de Almeida, Márcia Rogéria; Silva Júnior, Abelardo

2013-06-01

355

Correlation of Sperm and Endocrine Measures with Reproductive Success in Rodents.  

National Technical Information Service (NTIS)

The report compares the statistical precision and biological sensitivity of multiple indicies of reproductive function to infertility in the male rodent. The studies discussed include those that examined reproductive function in the male following perinat...

L. E. Gray J. Ostby J. Ferrell R. Sigmon R. Cooper

1989-01-01

356

Segment specification for the payload segment of the reusable reentry satellite: Rodent module version  

NASA Technical Reports Server (NTRS)

The Reusable Reentry Satellite (RRS) System is composed of the payload segment (PS), vehicle segment (VS), and mission support (MS) segments. This specification establishes the performance, design, development, and test requirements for the RRS Rodent Module (RM).

1991-01-01

357

Reducing Aquatic Rodent Damage through an Integrated Wildlife Damage Management Program in the State of Alabama.  

National Technical Information Service (NTIS)

The purpose of this Environmental Assessment (EA) is to analyze the potential environmental effects of the proposed Alabama WS beaver (Castor canadensis), nutria (Myocastor coypus), and muskrat (Ondatra zibethica) (hereafter referred to as aquatic rodents...

2002-01-01

358

Wildlife Habitat Relationships: Sampling Procedures for Pacific Northwest Vertebrates. Methods for Measuring Populations of Arboreal Rodents.  

National Technical Information Service (NTIS)

Three arboreal rodents are sensitive indicators of forest ecosystem function in the Pacific Northwest. The northern flying squirrel (Glaucomys sabrinus) is mycophagous, cavity-nesting, and a major prey of the spotted owl (Strix occidentalis). The red tree...

A. B. Carey L. F. Ruggiero B. L. Biswell J. W. Witt

1991-01-01

359

Responses of Herbivorous Rodents to Habitat Disturbance on the North Slope of Alaska. Progress Report.  

National Technical Information Service (NTIS)

The objectives were: (1) to determine the patterns of distribution and density of rodents along drainage systems, (2) to relate those patterns to changes in vegetation associated with disturbance, (3) to examine the mechanisms that account for observed pa...

G. O. Batzli

1985-01-01

360

COMPARATIVE MICROARRAY EXPRESSION ANALYSIS OF SELECTED CANCER RELEVANT GENES IN HYPERTENSIVE RESISTANT VERSUS SUSCEPTIBLE RODENT STRAINS  

EPA Science Inventory

Hypertension and cancer are prevalent diseases. Epidemiological studies suggest that hypertension may increase the long term risk of cancer. Identification of resistance and/or susceptibility genes using rodent models could provide important insights into the management and treat...

361

Factors influencing repeated seed movements by scatter-hoarding rodents in an alpine forest  

PubMed Central

Scatter-hoarding rodents are effective dispersal agents for many plant species. Several studies have shown that rodents repeatedly re-cache seeds. The re-caching process often has a significant impact on final seedling establishment, but the factors determining its occurrence are poorly understood. In this study, we followed the fate of 3564 artificial seeds that varied in size, nutrient content and tannin content. Seeds cached closer to their original releasing plots were more likely to be re-cached, and to a further distance. Larger seeds were more likely to be re-cached than smaller ones, while nutrient and tannin content had little effect. Most plant species that depend on scatter-hoarding rodents for seed dispersal bear relatively large seeds, and large seeds are usually more likely to be dispersed and to establish seedlings, suggesting that the caching preferences of scatter-hoarding rodents may have played an important role in the evolution of large seeds.

Wang, Bo; Chen, Jin; Corlett, Richard T.

2014-01-01

362

Detection of Toxoplasma gondii by PCR and Mouse Bioassay in Rodents of Ahvaz District, Southwestern Iran  

PubMed Central

Toxoplasma gondii is obligate coccidian zoonotic parasite. Felidae family is definitive and wide ranges of warm-blooded vertebrates are intermediate hosts for the parasite. Rodents are measured as an important source of T. gondii infection for the definitive host. Thus, this study aimed to investigate Toxoplasm infection in rodents of Ahvaz district, southwest of Iran. A total of 100 rodents (73 Rattus norvegicus, 21 Rattus rattus, and 6 Mus musculus) were collected and studied by GRA6PCR and mouse bioassay. The finding indicated that 6 out of 100 (6%) and 2 out of 100 (2%) samples were positive by PCR and mouse bioassay, respectively. The results show notable chronic infection in the rodent and potential transmission of the infection among animal and men in the region. Accordingly, this study recommended investigating of the T. gondii infection in definitive and other intermediate hosts in other points of Khuzestan province, Southwest, Iran.

Saki, J.; Khademvatan, S.

2014-01-01

363

Iron deficiency in the tropics.  

PubMed

Iron in food is classified as belonging to the haem pool, the nonhaem pool, and extraneous sources. Haem iron is derived from vegetable and animal sources with varying bioavailability. Hookworm infestation of the intestinal tract affects 450 million people in the tropics. Schistosoma mansoni caused blood loss in 7 Egyptian patients of 7.5- 25.9 ml/day which is equivalent to a daily loss of iron of .6-7.3 mg daily urinary loss of iron in 9 Egyptian patients. Trichuris trichiura infestation by whipworm is widespread in children with blood loss of 5 ml/day/worm. The etiology of anemia in children besides iron deficiency includes malaria, bacterial or viral infections, folate deficiency and sickle-cell disease. Severe infections cause profound iron-deficiency anemia in children in central American and Malaysia. Plasmodium falciparum malaria-induced anaemia in tropical Africa lowers the mean haemoglobin concentration in the population by 2 g/dI, causing profound anaemia in some. The increased risk of premature delivery, low birthweight, fetal abnormalities, and fetal death is directly related to the degree of maternal anemia. Perinatal mortality was reduced from 38 to 4% in treated anemic mothers. Mental performance was significantly lower in anemic school children and improved after they received iron. Supplements of iron, soy-protein, calcium, and vitamins given to villagers with widespread malnutrition, iron deficiency, and hookworm infestation in Colombia reduced enteric infections in children. Severe iron-deficiency anemia was treated in adults in northern Nigeria by daily in Ferastral 10 ml, which is equivalent to 500 mg of iron per day. Choloroquine, folic acid, rephenium hydroxynaphthoate, and tetrachlorethylene treat adults with severe iron deficiency from hookworm infestation in rural tropical Africa. Blood transfusion is indicated if the patient is dying of anaemia or is pregnant with a haemoglobin concentration 6 gm/dl. In South East Asia, mg per day prevented iron-deficiency anaemia in pregnancy. Field-trials on nutritional iron deficiency include an acidified milk formula plus ferrous sulphate for infants; biscuits with added bovine hemoglobin for children in Chile; sugar plus sodium ferric EDTA in Guatemala; salt with ferric orthophosphate and sodium acid sulphate in India; and Salt with ferrous sulphate plus sodium hexametaphosphate. PMID:7042157

Fleming, A F

1982-06-01

364

Experimental evaluation of rodent exclusion methods to reduce hantavirus transmission to humans in rural housing.  

PubMed

An experimental assessment of methods to reduce rodent infestations in rural housing was conducted in Yosemite National Park, California, Sequoia/Kings Canyon National Parks, California, and Shenandoah National Park, Virginia. During pretreatment surveys, nearly all (63 of 68) selected units had past or ongoing rodent activity inside. Active infestations were found in 58.8% of the units. Peromyscus spp. represented 91.2% of all animals caught inside housing units. Despite little harborage, rodent activity was common near housing (290 animals/2,254 trap nights). The most common species present was Peromyscus maniculatus (43-50% of all captures). This species was especially frequent (49-87% of Peromyscus captures) around the foundations of housing units. Habitat had little effect on captures. There were 1.8 Peromyscus caught per unit along the foundations of housing in modified rural settings with grass lawns compared with 1.2 Peromyscus caught per unit in sites located in mature woodlands. During autumn of 1994, randomly selected housing units were rodent proofed by sealing openings associated with chases, roof eaves, and attics with insulation and wire mesh. Housing was examined and the fauna was resampled in the spring-summer of 1995. Rodent-proofed houses were infested significantly less often (3 of 28) than control houses (13 of 36) (P = 0.02) and the intensity of infestation was lower in experimental houses (6 versus 23 mice/treatment). More than 25% of the mice trapped inside the houses had been marked outside the houses during the three-day surveys, demonstrating movement of mice adjacent to the buildings into not rodent-proofed housing. As in the previous autumn, most of the animals captured in (98.9%) and along the foundations of the houses (77.5%) were Peromyscus spp. These results demonstrate that Peromyscus frequently invade rural housing but rodent-proofing effectively eliminates or substantially reduces rodent activity. PMID:9158040

Glass, G E; Johnson, J S; Hodenbach, G A; Disalvo, C L; Peters, C J; Childs, J E; Mills, J N

1997-04-01

365

Visual Pigment Coexpression in All Cones of Two Rodents, the Siberian Hamster, and the Pouched Mouse  

Microsoft Academic Search

PURPOSE. To decide whether the identical topography of short- and middle-wavelength cone photoreceptors in two species of rodents reflects the presence of both opsins in all cone cells. METHODS. Double-label immunocytochemistry using antibodies directed against short-wavelength (S)- and middle- to long- wavelength (M\\/L)-sensitive opsin were used to determine the presence of visual pigments in cones of two species of rodents,

Akos Lukats; Ouria Dkhissi-Benyahya; Zsuzsanna Szepessy; Pal Rohlich; Bela Võ ´ gh; Nigel C. Bennett; Howard M. Cooper; Agoston Szel

2002-01-01

366

Natural Host Relationships and Genetic Diversity of Rodent-Associated Hantaviruses in Southeastern Brazil  

Microsoft Academic Search

Objective: Hantaviruses are rodent-borne RNA viruses that have caused hantavirus cardiopulmonary syndrome in several Brazilian regions. In the present study, geographical distribution, seroprevalence, natural host range, and phylogenetic relations of rodent-associated hantaviruses collected from seven counties of Southeastern Brazil were evaluated. Methods: ELISA, RT-PCR and phylogenetic analysis were used in this study. Results: Antibodies to hantavirus were detected in Bolomys

Ricardo Luiz Moro de Sousa; Marcos Lázaro Moreli; Alessandra Abel Borges; Gelse Mazzoni Campos; Márcia Cristina Livonesi; Luiz Tadeu Moraes Figueiredo; Aramis Augusto Pinto

2008-01-01

367

Adaptation for rodent pollination in Leucospermum arenarium (Proteaceae) despite rapid pollen loss during grooming.  

PubMed

Background and Aims Plants are adapted for rodent pollination in diverse and intricate ways. This study explores an extraordinary example of these adaptations in the pincushion Leucospermum arenarium (Proteaceae) from South Africa. Methods Live trapping and differential exclusion experiments were used to test the role of rodents versus birds and insects as pollinators. To explore the adaptive significance of geoflory, inflorescences were raised above ground level and seed production was compared. Captive rodents and flowers with artificial stigmas were used to test the effect of grooming on the rate of pollen loss. Microscopy, nectar composition analysis and manipulative experiments were used to investigate the bizarre nectar production and transport system. Key Results Differential exclusion of rodents, birds and insects demonstrated the importance of rodents in promoting seed production. Live trapping revealed that hairy-footed gerbils, Gerbillurus paeba, and striped field mice, Rhabdomys pumilio, both carried L. arenarium pollen on their forehead and rostrum, but much larger quantities ended up in faeces as a result of grooming. Terrarium experiments showed that grooming exponentially diminished the pollen loads that they carried. The nectar of L. arenarium was found to be unusually viscous and to be presented in a novel location on the petal tips, where rodents could access it without destroying the flowers. Nectar was produced inside the perianth, but was translocated to the petal tips via capillary ducts. In common with many other rodent-pollinated plants, the flowers are presented at ground level, but when raised to higher positions seed production was not reduced, indicating that selection through female function does not drive the evolution of geoflory. Conclusions Despite the apparent cost of pollen lost to grooming, L. arenarium has evolved remarkable adaptations for rodent pollination and provides the first case of this pollination system in the genus. PMID:24607723

Johnson, Christopher Michael; Pauw, Anton

2014-05-01

368

Rodent Allergen in Los Angeles Inner City Homes of Children with Asthma  

Microsoft Academic Search

Recent studies have examined the presence of mouse allergen in inner city children with asthma. Researchers have found high\\u000a levels of rodent allergen in homes sampled in the northeast and midwest United States, but there has been considerable variation\\u000a between cities, and there have been few studies conducted in western states. We evaluated the frequency of rodent sightings\\u000a and detectable

Jill Berg; Rob McConnell; Joel Milam; Judith Galvan; Jenny Kotlerman; Peter Thorne; Craig Jones; Ronald Ferdman; Peyton Eggleston; Cynthia Rand; Mary Ann Lewis; John Peters; Jean Richardson

2008-01-01

369

Ecological and Control Techniques for Sand Flies (Diptera: Psychodidae) Associated with Rodent Reservoirs of Leishmaniasis  

PubMed Central

Background Leishmaniasis remains a global health problem because of the substantial holes that remain in our understanding of sand fly ecology and the failure of traditional vector control methods. The specific larval food source is unknown for all but a few sand fly species, and this is particularly true for the vectors of Leishmania parasites. We provide methods and materials that could be used to understand, and ultimately break, the transmission cycle of zoonotic cutaneous leishmaniasis. Methods and Findings We demonstrated in laboratory studies that analysis of the stable carbon and nitrogen isotopes found naturally in plant and animal tissues was highly effective for linking adult sand flies with their larval diet, without having to locate or capture the sand fly larvae themselves. In a field trial, we also demonstrated using this technique that half of captured adult sand flies had fed as larvae on rodent feces. Through the identification of rodent feces as a sand fly larval habitat, we now know that rodent baits containing insecticides that have been shown in previous studies to pass into the rodents' feces and kill sand fly larvae also could play a future role in sand fly control. In a second study we showed that rubidium incorporated into rodent baits could be used to demonstrate the level of bloodfeeding by sand flies on baited rodents, and that the elimination of sand flies that feed on rodents can be achieved using baits containing an insecticide that circulates in the blood of baited rodents. Conclusions Combined, the techniques described could help to identify larval food sources of other important vectors of the protozoa that cause visceral or dermal leishmaniasis. Unveiling aspects of the life cycles of sand flies that could be targeted with insecticides would guide future sand fly control programs for prevention of leishmaniasis.

Mascari, Thomas M.; Hanafi, Hanafi A.; Jackson, Ryan E.; Ouahabi, Souad; Ameur, Btissam; Faraj, Chafika; Obenauer, Peter J.; Diclaro, Joseph W.; Foil, Lane D.

2013-01-01

370

Conserved expression and functions of PDE4 in rodent and human heart  

PubMed Central

PDE4 isoenzymes are critical in the control of cAMP signaling in rodent cardiac myocytes. Ablation of PDE4 affects multiple key players in excitation–contraction coupling and predisposes mice to the development of heart failure. As little is known about PDE4 in human heart, we explored to what extent cardiac expression and functions of PDE4 are conserved between rodents and humans. We find considerable similarities including comparable amounts of PDE4 activity expressed, expression of the same PDE4 subtypes and splicing variants, anchoring of PDE4 to the same subcellular compartments and macromolecular signaling complexes, and downregulation of PDE4 activity and protein in heart failure. The major difference between the species is a fivefold higher amount of non-PDE4 activity in human hearts compared to rodents. As a consequence, the effect of PDE4 inactivation is different in rodents and humans. PDE4 inhibition leads to increased phosphorylation of virtually all PKA substrates in mouse cardiomyocytes, but increased phosphorylation of only a restricted number of proteins in human cardiomyocytes. Our findings suggest that PDE4s have a similar role in the local regulation of cAMP signaling in rodent and human heart. However, inhibition of PDE4 has ‘global’ effects on cAMP signaling only in rodent hearts, as PDE4 comprises a large fraction of the total cardiac PDE activity in rodents but not in humans. These differences may explain the distinct pharmacological effects of PDE4 inhibition in rodent and human hearts. Electronic supplementary material The online version of this article (doi:10.1007/s00395-010-0138-8) contains supplementary material, which is available to authorized users.

Xie, Moses; Scheitrum, Colleen; Krall, Judith; Movsesian, Matthew A.; Conti, Marco

2010-01-01

371

Primitive fossil rodent from Inner Mongolia and its implications for mammalian phylogeny  

Microsoft Academic Search

THE evolutionary origin of rodents is obscured by the group's sudden and highly transformed first appearance in the fossil record1,2 in the latest Paleocene. We report here the discovery of nearly complete dental remains of an extraordinary new primitive rodent from strata of transitional Paleocene-Eocene age in Inner Mongolia, China. The strikingly conservative morphological features of this taxon, Tribosphenomys minutus,

Jin Meng; André R. Wyss; Mary R. Dawson; Renjie Zhai

1994-01-01

372

Crepuscular Rhythms of EEG Sleep-Wake in a Hystricomorph Rodent, Octodon degus  

Microsoft Academic Search

Sleep-wake circadian rhythms are well documented for nocturnal rodents, but little is known about sleep regulation in diurnal or crepuscular rodent species. This study examined the circadian sleep-wake rhythms in Octodon degus by means of electroencephalogram (EEG) analysis. Recordings were made from animals housed with or without running wheels in the cages. In a 24-h light-dark (LD) cycle (LD 12:12),

Martien J. H. Kas; Dale M. Edgar

1998-01-01

373

Rodents as receptor species at a tritium disposal site.  

PubMed

New methods are being employed on the Department of Energy's Savannah River Site to deal with the disposal of tritium, including the irrigation of a hardwood/pine forest with tritiated water from an intercepted contaminant plume to reduce concentrations of tritium outcropping into Fourmile Branch, a tributary of the Savannah River. The use of this system has proven to be an effective means of tritium disposal. To evaluate the impact of this activity on terrestrial biota, rodent species were captured on the tritium disposal site and a control site during two trapping seasons in order to assess tritium exposure resulting from the forest irrigation. Control site mice had background levels of tritium, 0.02 Bq/mL, with disposal site mice having significantly higher tritium concentrations, mean=34.86 Bq/mL. Whole body tritium concentrations of the mice captured at the disposal site were positively correlated with tritium application and negatively correlated with precipitation at the site. PMID:15829339

Kelsey-Wall, Angel; Seaman, John C; Jagoe, Charles H; Dallas, Cham E; Gaines, Karen F

2005-01-01

374

Near-infrared light penetration profile in the rodent brain.  

PubMed

Near-infrared (NIR) lasers find applications in neuro-medicine both for diagnostic and treatment purposes. Penetration depth and profile into neural tissue are critical parameters to be considered in these applications. Published data on the optical properties of rodent neural tissue are rare, despite the frequent use of rats as an animal model. The aim of this study was to measure the light intensity profile inside the rat brain using a direct method, while the medium is being illuminated by an NIR laser beam, and compare the results with in vitro measurements of transmittance in the rat brain slices. The intensity profile along the vertical axis had an exponential decline with multiple regions that could be approximated with different coefficients. The Monte Carlo method that was used to simulate light-tissue interactions and predict the scattering coefficient of brain tissue from the measurements suggested that more scattering occurred in deeper layers of the cortex. A single scattering coefficient of 125??cm-1 was estimated for cortical layers from 300 to 1500 ?m and a gradually increasing value from 125 to 370??cm-1 for depths of 1500 to 3000 ?m. The deviations of in vivo results from the in vitro transmittance measurements, as well as the postmortem in vivo results from the alive measurements were significant. PMID:23831713

Abdo, Ammar; Ersen, Ali; Sahin, Mesut

2013-01-01

375

Hepatoprotective effect of aged black garlic extract in rodents.  

PubMed

In this study, we investigated the hepatoprotective effects of aged black garlic (ABG) in rodent models of liver injury. ABG inhibited carbon tetrachloride-induced elevation of aspartate transaminase (AST) and alanine transaminase (ALT), which are markers of hepatocellular damage, in SD rats. D-galactosamineinduced hepatocellular damage was also suppressed by ABG treatment. However, ABG does not affect the elevation of alkaline phosphatase (ALP), a marker of hepatobilliary damage, in rats treated with carbon tetrachloride or D-galactosamine. We also examined the effect of ABG on high-fat diet (HFD)-induced fatty liver and subsequent liver damage. ABG had no significant effect on body weight increase and plasma lipid profile in HFD-fed mice. However, HFD-induced increase in AST and ALT, but not ALP, was significantly suppressed by ABG treatment. These results demonstrate that ABG has hepatoprotective effects and suggest that ABG supplementation might be a good adjuvant therapy for the management of liver injury. PMID:24795800

Shin, Jung Hyu; Lee, Chang Woo; Oh, Soo Jin; Yun, Jieun; Kang, Moo Rim; Han, Sang-Bae; Park, Heungsik; Jung, Jae Chul; Chung, Yoon Hoo; Kang, Jong Soon

2014-03-01

376

Dependence Potential of Quetiapine: Behavioral Pharmacology in Rodents  

PubMed Central

Quetiapine is an atypical or second-generation antipsychotic agent and has been a subject of a series of case report and suggested to have the potential for misuse or abuse. However, it is not a controlled substance and is not generally considered addictive. In this study, we examined quetiapine’s dependence potential and abuse liability through animal behavioral tests using rodents to study the mechanism of quetiapine. Molecular biology techniques were also used to find out the action mechanisms of the drug. In the animal behavioral tests, quetiapine did not show any positive effect on the experimental animals in the climbing, jumping, and conditioned place preference tests. However, in the head twitch and self-administration tests, the experimental animals showed significant positive responses. In addition, the action mechanism of quetiapine was found being related to dopamine and serotonin release. These results demonstrate that quetiapine affects the neurological systems related to abuse liability and has the potential to lead psychological dependence, as well.

Cha, Hye Jin; Lee, Hyun-A; Ahn, Joon-Ik; Jeon, Seol-Hee; Kim, Eun Jung; Jeong, Ho-Sang

2013-01-01

377

The Behavioral Actions of Lithium in Rodent Models  

PubMed Central

For nearly as long as lithium has been in clinical use for the treatment of bipolar disorder, depression, and other conditions, investigators have attempted to characterize its effects on behaviors in rodents. Lithium consistently decreases exploratory activity, rearing, aggression, and amphetamine-induced hyperlocomotion; and it increases the sensitivity to pilocarpine-induced seizures, decreases immobility time in the forced swim test, and attenuates reserpine-induced hypolocomotion. Lithium also predictably induces conditioned taste aversion and alterations in circadian rhythms. The modulation of stereotypy, sensitization, and reward behavior are less consistent actions of the drug. These behavioral models may be relevant to human symptoms and to clinical endophenotypes. It is likely that the actions of lithium in a subset of these animal models are related to the therapeutic efficacy, as well the side effects, of the drug. We conclude with a brief discussion of various molecular mechanisms by which these lithium-sensitive behaviors may be mediated, and comment on the ways in which rat and mouse models can be used more effectively in the future to address persistent questions about the therapeutically relevant molecular actions of lithium.

O'Donnell, Kelley C.; Gould, Todd D.

2007-01-01

378

An Experimental Model for Resistance Exercise in Rodents  

PubMed Central

This study aimed to develop an equipment and system of resistance exercise (RE), based on squat-type exercise for rodents, with control of training variables. We developed an operant conditioning system composed of sound, light and feeding devices that allowed optimized RE performance by the animal. With this system, it is not necessary to impose fasting or electric shock for the animal to perform the task proposed (muscle contraction). Furthermore, it is possible to perform muscle function tests in vivo within the context of the exercise proposed and control variables such as intensity, volume (sets and repetitions), and exercise session length, rest interval between sets and repetitions, and concentric strength. Based on the experiments conducted, we demonstrated that the model proposed is able to perform more specific control of other RE variables, especially rest interval between sets and repetitions, and encourages the animal to exercise through short-term energy restriction and “disturbing” stimulus that do not promote alterations in body weight. Therefore, despite experimental limitations, we believe that this RE apparatus is closer to the physiological context observed in humans.

Nicastro, Humberto; Zanchi, Nelo Eidy; da Luz, Claudia Ribeiro; Chaves, Daniela Fojo Seixas; Lancha, Antonio Herbert

2012-01-01

379

Multimodal imaging of neural progenitor cell fate in rodents.  

PubMed

For clinical application of stem cell-based therapies, noninvasive detection of applied stem cells is of high importance. We report on the feasibility of detecting implanted neural progenitor cells (NPCs) noninvasively and follow their fate and functional status by sequential multimodal molecular imaging and reporter gene technology. We investigated C17.2 cells stably expressing herpes simplex virus type 1-thymidine kinase (HSV-1-tk) and green fluorescent protein (gfp) (C17.2-tkIRESgfp = C17.2-TIG) or HSV-1-tk, gfp, and firefly luciferase (luc) (C17.2-lucIREStkgfp = C17.2-LITG) and determined the detection sensitivity of positron emission tomography (PET) and bioluminescence imaging (BLI) for these cells in culture and in vivo in subcutaneous and intracranial glioma models. In addition, PET and BLI were used to further investigate and follow the fate of implanted C17.2-LITG cells in an intracranial glioma model. We show that both imaging modalities are sensitive in detecting reporter gene expressing NPCs; however, PET, by the use of 9-[4-[(18)F]fluoro-3-hydroxymethyl)butyl]guanine ([(18)F]FHBG), detects NPCs only at sites of disrupted blood-brain barrier. Furthermore, both imaging modalities can be used to detect stem cell fate and migration and indicate excessive proliferation and aberrant migration. In conclusion, multimodal imaging can be used for longitudinal noninvasive monitoring of grafted NPCs in rodents. PMID:18706290

Waerzeggers, Yannic; Klein, Markus; Miletic, Hrvoje; Himmelreich, Uwe; Li, Hongfeng; Monfared, Parisa; Herrlinger, Ulrich; Hoehn, Mathias; Coenen, Heinrich Hubert; Weller, Michael; Winkeler, Alexandra; Jacobs, Andreas Hans

2008-01-01

380

PhenoWorld: a new paradigm to screen rodent behavior  

PubMed Central

Modeling depression in animals has inherent complexities that are augmented by intrinsic difficulties to measure the characteristic features of the disorder. Herein, we describe the PhenoWorld (PhW), a new setting in which groups of six rats lived in an ethological enriched environment, and have their feeding, locomotor activity, sleeping and social behavior automatically monitored. A battery of emotional and cognitive tests was used to characterize the behavioral phenotype of animals living in the PhW and in standard conditions (in groups of six and two rats), after exposure to an unpredictable chronic mild stress paradigm (uCMS) and antidepressants. Data reveal that animals living in the PhW displayed similar, but more striking, behavioral differences when exposed to uCMS, such as increased behavioral despair shown in the forced swimming test, resting/sleep behavior disturbances and reduced social interactions. Moreover, several PhW-cage behaviors, such as spontaneous will to go for food or exercise in running wheels, proved to be sensitive indicators of depressive-like behavior. In summary, this new ethological enriched paradigm adds significant discriminative power to screen depressive-like behavior, in particularly rodent's hedonic behavior.

Castelhano-Carlos, M; Costa, P S; Russig, H; Sousa, N

2014-01-01

381

Use of rodents as models of human diseases  

PubMed Central

Advances in molecular biology have significantly increased the understanding of the biology of different diseases. However, these discoveries have not yet been fully translated into improved treatments for patients with diseases such as cancers. One of the factors limiting the translation of knowledge from preclinical studies to the clinic has been the limitations of in vivo diseases models. In this brief review, we will discuss the advantages and disadvantages of rodent models that have been developed to simulate human pathologies, focusing in models that employ xenografts and genetic modification. Within the framework of genetically engineered mouse (GEM) models, we will review some of the current genetic strategies for modeling diseases in the mouse and the preclinical studies that have already been undertaken. We will also discuss how recent improvements in imaging technologies may increase the information derived from using these GEMs during early assessments of potential therapeutic pathways. Furthermore, it is interesting to note that one of the values of using a mouse model is the very rapid turnover rate of the animal, going through the process of birth to death in a very short timeframe relative to that of larger mammalian species.

Vandamme, Thierry F.

2014-01-01

382

Liver carcinogenesis: rodent models of hepatocarcinoma and cholangiocarcinoma.  

PubMed

Hepatocellular carcinoma and cholangiocarcinoma are primary liver cancers, both represent a growing challenge for clinicians due to their increasing morbidity and mortality. In the last few years a number of in vivo models of hepatocellular carcinoma and cholangiocarcinoma have been developed. The study of these models is providing a significant contribution in unveiling the pathophysiology of primary liver malignancies. They are also fundamental tools to evaluate newly designed molecules to be tested as new potential therapeutic agents in a pre-clinical set. Technical aspects of each model are critical steps, and they should always be considered in order to appropriately interpret the findings of a study or its planning. The purpose of this review is to describe the technical and experimental features of the most significant rodent models, highlighting similarities or differences between the corresponding human diseases. The first part is dedicated to the discussion of models of hepatocellular carcinoma, developed using toxic agents, or through dietary or genetic manipulations. In the second we will address models of cholangiocarcinoma developed in rats or mice by toxin administration, genetic manipulation and/or bile duct incannulation or surgery. Xenograft or syngenic models are also proposed. PMID:23177172

De Minicis, Samuele; Kisseleva, Tatiana; Francis, Heather; Baroni, Gianluca Svegliati; Benedetti, Antonio; Brenner, David; Alvaro, Domenico; Alpini, Gianfranco; Marzioni, Marco

2013-06-01

383

Purification of pericytes from rodent optic nerve by immunopanning.  

PubMed

This protocol describes the use of immunopanning to purify rodent pericytes from the optic nerve. Immunopanning permits the prospective isolation of pericytes from optic nerve tissue by relying on the binding of pericytes to an anti-PDGFR? (platelet-derived growth factor receptor beta) antibody adhered to a Petri dish. The cells are viable at the end of this gentle procedure, and they can be analyzed acutely for gene expression or cultured alone or in coculture with other central nervous system (CNS) cell types, including CNS endothelial cells and CNS astrocytes. As written, this procedure is used for isolation of optic nerve pericytes from the rat. The same PDGFR? antibodies can be used for purifying optic nerve pericytes from the mouse, but alternate negative panning antibodies must be used to ensure that astrocytes do not contaminate the preparation. This procedure can also be modified to purify pericytes from the brain. The same PDGFR? antibody is used, but additional steps (specific dissections or negative panning) are required to ensure that other PDGFR?-positive contaminants, including cells from the rostral migratory stream, are depleted from the cell suspension. PMID:24890207

Zhou, Lu; Sohet, Fabien; Daneman, Richard

2014-01-01

384

Optically induced occlusion of single blood vessels in rodent neocortex.  

PubMed

The ability to form targeted vascular occlusions in small vessels of the brain is an important technique for studying the microscopic basis of cerebral ischemia. We describe two complementary methods that enable targeted occlusion of any single blood vessel within the upper 500 µm of adult rodent neocortex. Our goal is to generate highly localized regions of ischemia by blocking penetrating arterioles and ascending venules, which are bottlenecks of flow in the cortical angioarchitecture. One method, termed photothrombosis, makes use of linear optical absorption by a photosensitizer, transiently circulated in the blood stream, to induce a clot in a surface or near-surface segment of a vessel. The second method, termed plasma-mediated ablation, makes use of nonlinear optical interactions, without the need to introduce an exogenous absorber, to induce clots in subsurface segments of penetrating vessels, as well as subsurface microvessels and capillaries. The choice of the method for occlusion of individual vessels depends on the location of the vessels being studied and the objectives of the study. Here we describe concurrent high resolution in vivo imaging and auxiliary laser setups, occlusion protocols, and post hoc histological procedures. PMID:24298038

Shih, Andy Y; Nishimura, Nozomi; Nguyen, John; Friedman, Beth; Lyden, Patrick D; Schaffer, Chris B; Kleinfeld, David

2013-12-01

385

Geometric determinants of airway resistance in two isomorphic rodent species.  

PubMed

The flow resistance of the pulmonary airway tree (Raw) is disproportionately larger in large animals than in smaller ones. This is thought to be due to the fact that smaller animals have relatively wider central airways than larger animals. However, Raw is not determined solely by the diameter of the main bronchi or trachea. It depends on the dimensions of all the individual airways and how they are connected. We investigated how the degree of asymmetry of the airway tree, the number of airway orders, and dimensions of the individual airways combine to determine Raw. We performed this investigation using computer models of the airway trees of two different sized isomorphic rodents that differ in weight by more than two orders of magnitude-the harvest mouse and the giant pouched rat. We calculated airway resistance in these models under various conditions, and confirmed that the smaller species has a lower Raw relative to body size than the larger species. We also showed that these differences are due to a combination of differences both in relative airway diameters and in the degree of asymmetry of the airway trees. PMID:12093628

Gomes, Rute F M; Bates, Jason H T

2002-06-01

386

Acute Blast Injury Reduces Brain Abeta in Two Rodent Species  

PubMed Central

Blast-induced traumatic brain injury (TBI) has been a major cause of morbidity and mortality in the conflicts in Iraq and Afghanistan. How the primary blast wave affects the brain is not well understood. In particular, it is unclear whether blast injures the brain through mechanisms similar to those found in non-blast closed impact injuries (nbTBI). The ?-amyloid (A?) peptide associated with the development of Alzheimer’s disease is elevated acutely following TBI in humans as well as in experimental animal models of nbTBI. We examined levels of brain A? following experimental blast injury using enzyme-linked immunosorbent assays for A? 40 and 42. In both rat and mouse models of blast injury, rather than being increased, endogenous rodent brain A? levels were decreased acutely following injury. Levels of the amyloid precursor protein (APP) were increased following blast exposure although there was no evidence of axonal pathology based on APP immunohistochemical staining. Unlike the findings in nbTBI animal models, levels of the ?-secretase, ?-site APP cleaving enzyme 1, and the ?-secretase component presenilin-1 were unchanged following blast exposure. These studies have implications for understanding the nature of blast injury to the brain. They also suggest that strategies aimed at lowering A? production may not be effective for treating acute blast injury to the brain.

De Gasperi, Rita; Gama Sosa, Miguel A.; Kim, Soong Ho; Steele, John W.; Shaughness, Michael C.; Maudlin-Jeronimo, Eric; Hall, Aaron A.; DeKosky, Steven T.; McCarron, Richard M.; Nambiar, Madhusoodana P.; Gandy, Sam; Ahlers, Stephen T.; Elder, Gregory A.

2012-01-01

387

What Can We Learn from Rodents about Prolactin in Humans?  

PubMed Central

Prolactin (PRL) is a 23-kDa protein hormone that binds to a single-span membrane receptor, a member of the cytokine receptor superfamily, and exerts its action via several interacting signaling pathways. PRL is a multifunctional hormone that affects multiple reproductive and metabolic functions and is also involved in tumorigenicity. In addition to being a classical pituitary hormone, PRL in humans is produced by many tissues throughout the body where it acts as a cytokine. The objective of this review is to compare and contrast multiple aspects of PRL, from structure to regulation, and from physiology to pathology in rats, mice, and humans. At each juncture, questions are raised whether, or to what extent, data from rodents are relevant to PRL homeostasis in humans. Most current knowledge on PRL has been obtained from studies with rats and, more recently, from the use of transgenic mice. Although this information is indispensable for understanding PRL in human health and disease, there is sufficient disparity in the control of the production, distribution, and physiological functions of PRL among these species to warrant careful and judicial extrapolation to humans.

Ben-Jonathan, Nira; LaPensee, Christopher R.; LaPensee, Elizabeth W.

2008-01-01

388

Near-infrared light penetration profile in the rodent brain  

PubMed Central

Abstract. Near-infrared (NIR) lasers find applications in neuro-medicine both for diagnostic and treatment purposes. Penetration depth and profile into neural tissue are critical parameters to be considered in these applications. Published data on the optical properties of rodent neural tissue are rare, despite the frequent use of rats as an animal model. The aim of this study was to measure the light intensity profile inside the rat brain using a direct method, while the medium is being illuminated by an NIR laser beam, and compare the results with in vitro measurements of transmittance in the rat brain slices. The intensity profile along the vertical axis had an exponential decline with multiple regions that could be approximated with different coefficients. The Monte Carlo method that was used to simulate light–tissue interactions and predict the scattering coefficient of brain tissue from the measurements suggested that more scattering occurred in deeper layers of the cortex. A single scattering coefficient of 125??cm?1 was estimated for cortical layers from 300 to 1500 ?m and a gradually increasing value from 125 to 370??cm?1 for depths of 1500 to 3000 ?m. The deviations of in vivo results from the in vitro transmittance measurements, as well as the postmortem in vivo results from the alive measurements were significant.

Abdo, Ammar; Ersen, Ali; Sahin, Mesut

2013-01-01

389

Liver carcinogenesis: Rodent models of hepatocarcinoma and cholangiocarcinoma  

PubMed Central

Hepatocellular carcinoma and cholangiocarcinoma are primary liver cancers, both represent a growing challenge for clinicians due to their increasing morbidity and mortality. In the last few years a number of in vivo models of hepatocellular carcinoma and cholangiocarcinoma have been developed. The study of these models is providing a significant contribution in unveiling the pathophysiology of primary liver malignancies. They are also fundamental tools to evaluate newly designed molecules to be tested as new potential therapeutic agents in a pre-clinical set. Technical aspects of each model are critical steps, and they should always be considered in order to appropriately interpret the findings of a study or its planning. The purpose of this review is to describe the technical and experimental features of the most significant rodent models, highlighting similarities or differences between the corresponding human diseases. The first part is dedicated to the discussion of models of hepatocellular carcinoma, developed using toxic agents, or through dietary or genetic manipulations. In the second we will address models of cholangiocarcinoma developed in rats or mice by toxin administration, genetic manipulation and/or bile duct incannulation or surgery. Xenograft or syngenic models are also proposed.

Minicis, Samuele De; Kisseleva, Tatiana; Francis, Heather; Baroni, Gianluca Svegliati; Benedetti, Antonio; Brenner, David; Alvaro, Domenico; Alpini, Gianfranco; Marzioni, Marco

2013-01-01

390

Rodent-borne hantaviruses in Cambodia, Lao PDR, and Thailand.  

PubMed

In order to evaluate the circulation of hantaviruses present in southeast Asia, a large scale survey of small mammal species was carried out at seven main sites in the region (Cambodia, Lao People's Democratic Republic, and Thailand). Small scale opportunistic trapping was also performed at an eighth site (Cambodia). Using a standard IFA test, IgG antibodies reacting to Hantaan virus antigens were detected at six sites. Antibody prevalence at each site varied from 0 to 5.6% with antibodies detected in several rodent species (Bandicota indica, B. savilei, Maxomys surifer, Mus caroli, M. cookii, Rattus exulans, R. nitidius, R. norvegicus, and R. tanezumi). When site seroprevalence was compared with site species richness, seropositive animals were found more frequently at sites with lower species richness. In order to confirm which hantavirus species were present, a subset of samples was also subjected to RT-PCR. Hantaviral RNA was detected at a single site from each country. Sequencing confirmed the presence of two hantavirus species, Thailand and Seoul viruses, including one sample (from Lao PDR) representing a highly divergent strain of Seoul virus. This is the first molecular evidence of hantavirus in Lao PDR and the first reported L segment sequence data for Thailand virus. PMID:22124701

Blasdell, Kim; Cosson, Jean François; Chaval, Yannick; Herbreteau, Vincent; Douangboupha, Bounneuang; Jittapalapong, Sathaporn; Lundqvist, Ake; Hugot, Jean-Pierre; Morand, Serge; Buchy, Philippe

2011-12-01

391

Sexual Differentiation of the Rodent Brain: Dogma and Beyond  

PubMed Central

Steroid hormones of gonadal origin act on the neonatal brain to produce sex differences that underlie adult reproductive physiology and behavior. Neuronal sex differences occur on a variety of levels, including differences in regional volume and/or cell number, morphology, physiology, molecular signaling, and gene expression. In the rodent, many of these sex differences are determined by steroid hormones, particularly estradiol, and are established by diverse downstream effects. One brain region that is potently organized by estradiol is the preoptic area (POA), a region critically involved in many behaviors that show sex differences, including copulatory and maternal behaviors. This review focuses on the POA as a case study exemplifying the depth and breadth of our knowledge as well as the gaps in understanding the mechanisms through which gonadal hormones produce lasting neural and behavioral sex differences. In the POA, multiple cell types, including neurons, astrocytes, and microglia are masculinized by estradiol. Multiple downstream molecular mediators are involved, including prostaglandins, various glutamate receptors, protein kinase A, and several immune signaling molecules. Moreover, emerging evidence indicates epigenetic mechanisms maintain sex differences in the POA that are organized perinatally and thereby produce permanent behavioral changes. We also review emerging strategies to better elucidate the mechanisms through which genetics and epigenetics contribute to brain and behavioral sex differences.

Lenz, Kathryn M.; Nugent, Bridget M.; McCarthy, Margaret M.

2012-01-01

392

Expensive Brains: "Brainy" Rodents have Higher Metabolic Rate  

PubMed Central

Brains are the centers of the nervous system of animals, controlling the organ systems of the body and coordinating responses to changes in the ecological and social environment. The evolution of traits that correlate with cognitive ability, such as relative brain size is thus of broad interest. Brain mass relative to body mass (BM) varies among mammals, and diverse factors have been proposed to explain this variation. A recent study provided evidence that energetics play an important role in brain evolution (Isler and van Schaik, 2006). Using composite phylogenies and data drawn from multiple sources, these authors showed that basal metabolic rate (BMR) correlates with brain mass across mammals. However, no such relationship was found within rodents. Here we re-examined the relationship between BMR and brain mass within Rodentia using a novel species-level phylogeny. Our results are sensitive to parameter evaluation; in particular how species mass is estimated. We detect no pattern when applying an approach used by previous studies, where each species BM is represented by two different numbers, one being the individual that happened to be used for BMR estimates of that species. However, this approach may compromise the analysis. When using a single value of BM for each species, whether representing a single individual, or available species mean, our findings provide evidence that brain mass (independent of BM) and BMR are correlated. These findings are thus consistent with the hypothesis that large brains evolve when the payoff for increased brain mass is greater than the energetic cost they incur.

Sobrero, Raul; May-Collado, Laura J.; Agnarsson, Ingi; Hernandez, Cristian E.

2011-01-01

393

Nucleofection of rodent neuroblasts to study neuroblast migration in vitro.  

PubMed

The subventricular zone (SVZ) located in the lateral wall of the lateral ventricles plays a fundamental role in adult neurogenesis. In this restricted area of the brain, neural stem cells proliferate and constantly generate neuroblasts that migrate tangentially in chains along the rostral migratory stream (RMS) to reach the olfactory bulb (OB). Once in the OB, neuroblasts switch to radial migration and then differentiate into mature neurons able to incorporate into the preexisting neuronal network. Proper neuroblast migration is a fundamental step in neurogenesis, ensuring the correct functional maturation of newborn neurons. Given the ability of SVZ-derived neuroblasts to target injured areas in the brain, investigating the intracellular mechanisms underlying their motility will not only enhance the understanding of neurogenesis but may also promote the development of neuroregenerative strategies. This manuscript describes a detailed protocol for the transfection of primary rodent RMS postnatal neuroblasts and the analysis of their motility using a 3D in vitro migration assay recapitulating their mode of migration observed in vivo. Both rat and mouse neuroblasts can be quickly and efficiently transfected via nucleofection with either plasmid DNA, small hairpin (sh)RNA or short interfering (si)RNA oligos targeting genes of interest. To analyze migration, nucleofected cells are reaggregated in 'hanging drops' and subsequently embedded in a three-dimensional matrix. Nucleofection per se does not significantly impair the migration of neuroblasts. Pharmacological treatment of nucleofected and reaggregated neuroblasts can also be performed to study the role of signaling pathways involved in neuroblast migration. PMID:24300093

Falenta, Katarzyna; Gajendra, Sangeetha; Sonego, Martina; Doherty, Patrick; Lalli, Giovanna

2013-01-01

394

OCT-aided anastomosis platform study in the rodent model  

NASA Astrophysics Data System (ADS)

Anastomosis is one of the most commonly performed procedure in the clinical environment that involves tubular structures, such as blood vessel, lymphatic vessel, seminal duct and ureter. Suture based anastomosis is still the foundation for most basic surgical training and clinical operation, although alternate techniques have been developed and under development. For those tubular-structure-anastomosis, immediate real-time post-operative evaluation of the surgical outcome is critical to the success of surgery. Previously evaluation is mostly based on surgeons' experience. Fourier-domain optical coherence tomography is high-speed, high-resolution noninvasive 3D imaging modality that has been widely used in the biomedical research and clinical study. In this study we used Fourier-domain optical coherence tomography as an evaluation tool for anastomosis of lymphatic vessels, ureter and seminal duct in rodent model. Immediate post-operative and long term surgical site data were collected and analyzed. Critical clinical parameters such as lumen patency, anastomosed site narrowing and suture error detection are provided to surgeons.

Huang, Yong; Tong, Dedi; Zhu, Shan; Wu, Lehao; Ibrahim, Zuhaib; Lee, WP Andrew; Brandacher, Gerald; Kang, Jin U.

2014-02-01

395

Automated Tracking of Whiskers in Videos of Head Fixed Rodents  

PubMed Central

We have developed software for fully automated tracking of vibrissae (whiskers) in high-speed videos (>500 Hz) of head-fixed, behaving rodents trimmed to a single row of whiskers. Performance was assessed against a manually curated dataset consisting of 1.32 million video frames comprising 4.5 million whisker traces. The current implementation detects whiskers with a recall of 99.998% and identifies individual whiskers with 99.997% accuracy. The average processing rate for these images was 8 Mpx/s/cpu (2.6 GHz Intel Core2, 2 GB RAM). This translates to 35 processed frames per second for a 640 px×352 px video of 4 whiskers. The speed and accuracy achieved enables quantitative behavioral studies where the analysis of millions of video frames is required. We used the software to analyze the evolving whisking strategies as mice learned a whisker-based detection task over the course of 6 days (8148 trials, 25 million frames) and measure the forces at the sensory follicle that most underlie haptic perception.

Clack, Nathan G.; O'Connor, Daniel H.; Huber, Daniel; Petreanu, Leopoldo; Hires, Andrew; Peron, Simon; Svoboda, Karel; Myers, Eugene W.

2012-01-01

396

Validating Excised Rodent Lungs for Functional Hyperpolarized Xenon-129 MRI  

PubMed Central

Ex vivo rodent lung models are explored for physiological measurements of respiratory function with hyperpolarized (hp) 129Xe MRI. It is shown that excised lung models allow for simplification of the technical challenges involved and provide valuable physiological insights that are not feasible using in vivo MRI protocols. A custom designed breathing apparatus enables MR images of gas distribution on increasing ventilation volumes of actively inhaled hp 129Xe. Straightforward hp 129Xe MRI protocols provide residual lung volume (RV) data and permit for spatially resolved tracking of small hp 129Xe probe volumes during the inhalation cycle. Hp 129Xe MRI of lung function in the excised organ demonstrates the persistence of post mortem airway responsiveness to intravenous methacholine challenges. The presented methodology enables physiology of lung function in health and disease without additional regulatory approval requirements and reduces the technical and logistical challenges with hp gas MRI experiments. The post mortem lung functional data can augment histological measurements and should be of interest for drug development studies.

Lilburn, David M. L.; Hughes-Riley, Theodore; Six, Joseph S.; Stupic, Karl F.; Shaw, Dominick E.; Pavlovskaya, Galina E.; Meersmann, Thomas

2013-01-01

397

Mapping functional activity in rodent cortex using optical intrinsic signals.  

PubMed

We have investigated the dynamic response of rodent posteromedial barrel subfield (PMBSF) cortex to mechanical whisker deflection, using optical intrinsic signal imaging. While electrophysiologic response in barrel cortex has been well studied, dynamic metabolic changes affecting activity-related perfusion or oxidative enzymes are not well understood. Male Sprague-Dawley rats were anesthetized. Contralateral single and multiple vibrissae were deflected while images of somatosensory cortex were acquired with a charge-coupled-device camera. Intrinsic signals were observed over PMBSF as stimulus-related reflectance decreases (10(-3) of baseline) comprising two distinct spatiotemporal components. At 610 nm the first, diffuse, component begins 0.5-1 sec after stimulus onset, peaks at 2.5-3 sec, and returns to baseline by 4-5 sec. The second component is macrovascular, beginning at 1-1.5 sec, peaking at 3 sec, and dissipating by 5-6 sec. Similar patterns were observed at 550 nm and 850 nm. Signal size and location varied with the stimulus. Evoked potentials were found to have maximal amplitude in the region of maximal optical signals, diminishing toward the optical periphery. We have demonstrated PMBSF response to vibrissal deflection using optical reflectance methods. These intrinsic signals overlie regions of maximal electrophysiologic response, but commence, peak, and extinguish over a time scale of seconds from stimulus onset. They most likely indicate activity-related microvascular recruitment and chromophore redox changes. PMID:8038568

Narayan, S M; Santori, E M; Toga, A W

1994-01-01

398

Indirect food web interactions mediated by predator-rodent dynamics: relative roles of lemmings and voles  

PubMed Central

Production cycles in birds are proposed as prime cases of indirect interactions in food webs. They are thought to be driven by predators switching from rodents to bird nests in the crash phase of rodent population cycles. Although rodent cycles are geographically widespread and found in different rodent taxa, bird production cycles appear to be most profound in the high Arctic where lemmings dominate. We hypothesized that this may be due to arctic lemmings inducing stronger predator responses than boreal voles. We tested this hypothesis by estimating predation rates in dummy bird nests during a rodent cycle in low-Arctic tundra. Here, the rodent community consists of a spatially variable mix of one lemming (Lemmus lemmus) and two vole species (Myodes rufocanus and Microtus oeconomus) with similar abundances. In consistence with our hypothesis, lemming peak abundances predicted well crash-phase nest predation rates, whereas the vole abundances had no predictive ability. Corvids were found to be the most important nest predators. Lemmings appear to be accessible to the whole predator community which makes them particularly powerful drivers of food web dynamics.

Ims, Rolf A.; Henden, John-Andre; Thingnes, Anders V.; Killengreen, Siw T.

2013-01-01

399

A comparison of bats and rodents as reservoirs of zoonotic viruses: are bats special?  

USGS Publications Warehouse

Bats are the natural reservoirs of a number of high-impact viral zoonoses. We present a quantitative analysis to address the hypothesis that bats are unique in their propensity to host zoonotic viruses based on a comparison with rodents, another important host order. We found that bats indeed host more zoonotic viruses per species than rodents, and we identified life-history and ecological factors that promote zoonotic viral richness. More zoonotic viruses are hosted by species whose distributions overlap with a greater number of other species in the same taxonomic order (sympatry). Specifically in bats, there was evidence for increased zoonotic viral richness in species with smaller litters (one young), greater longevity and more litters per year. Furthermore, our results point to a new hypothesis to explain in part why bats host more zoonotic viruses per species: the stronger effect of sympatry in bats and more viruses shared between bat species suggests that interspecific transmission is more prevalent among bats than among rodents. Although bats host more zoonotic viruses per species, the total number of zoonotic viruses identified in bats (61) was lower than in rodents (68), a result of there being approximately twice the number of rodent species as bat species. Therefore, rodents should still be a serious concern as reservoirs of emerging viruses. These findings shed light on disease emergence and perpetuation mechanisms and may help lead to a predictive framework for identifying future emerging infectious virus reservoirs.

Luis, Angela D.; Hayman, David T. S.; O'Shea, Thomas J.; Cryan, Paul M.; Gilbert, Amy T.; Pulliam, Juliet R. C.; Mills, James N.; Timonin, Mary E.; Willis, Craig K. R.; Cunningham, Andrew A.; Fooks, Anthony R.; Rupprecht, Charles E.; Wood, James L. N.; Webb, Colleen T.

2013-01-01

400

Prevalence and Diversity of Bartonella Species in Commensal Rodents and Ectoparasites from Nigeria, West Africa  

PubMed Central

Background Bartonellae are fastidious bacteria causing persistent bacteremia in humans and a wide variety of animals. In recent years there is an increasing interest in mammalian bartonelloses in general and in rodent bartonelloses in particular. To date, no studies investigating the presence of Bartonella spp. in rodents and ectoparasites from Nigeria were carried out. Methodology/Principal Findings The aim of the current study was to investigate the presence of Bartonella spp. in commensal rodents and their ectoparasites in Nigeria. We report, for the first time, the molecular detection of Bartonella in 26% (46/177) of commensal rodents (Rattus rattus, R. norvegicus and Cricetomys gambianus) and 28% (9/32) of ectoparasite pools (Xenopsylla cheopis, Haemolaelaps spp., Ctenophthalmus spp., Hemimerus talpoides, and Rhipicephalus sanguineus) from Nigeria. Sequence analysis of the citrate synthase gene (gltA) revealed diversity of Bartonella spp. and genotypes in Nigerian rodents and their ectoparasites. Bartonella spp. identical or closely related to Bartonella elizabethae, Bartonella tribocorum and Bartonella grahamii were detected. Conclusions/Significance High prevalence of infection with Bartonella spp. was detected in commensal rodents and ectoparasites from Nigeria. The Bartonella spp. identified were previously associated with human diseases highlighting their importance to public health. Further studies need to be conducted to determine whether the identified Bartonella species could be responsible for human cases of febrile illness in Nigeria.

Kamani, Joshua; Morick, Danny; Mumcuoglu, Kosta Y.; Harrus, Shimon

2013-01-01

401

Oxidative and nutrient stability of a standard rodent spaceflight diet during long-term storage.  

PubMed

The National Aeronautics and Space Administration's standard spaceflight diet for rodents is the nutrient-upgraded rodent food bar (NuRFB). The shelf life of the NuRFB needs to be determined in order to avoid malnutrition of rodents and confounding of research results resulting from nutritional deficiency. The authors compared the oxidative and nutrient stability of NuRFBs stored at either ambient temperature (26 °C) or at refrigeration temperature (4 °C) for use in long-term rodent feeding experiments. After 0, 3, 6, 9 and 12 months (mo) of storage, lipid oxidation, fatty acid composition and amounts of specific vitamins and amino acids in NuRFBs were analyzed. No oxidative rancidity developed in NuRFBs stored at 4 °C for up to 12 mo, but NuRFBs stored at 26 °C for 6 mo developed oxidative rancidity and had reduced amounts of ?-linolenic acid (18:3n-6). Despite loss of vitamin E, vitamin A and thiamin after storage at 26 °C for 12 mo, vitamin levels in NuRFBs remained at or above the levels recommended for optimal rodent health. The amino acid profile of NuRFBs was unaffected by storage at 4 °C or 26 °C for 12 mo. The results suggest that NuRFBs stored at 4 °C for up to 12 mo and NuRFBs stored at 26 °C for up to 6 mo provide suitable nutrition for rodents in long-term experiments. PMID:22914028

Sun, Gwo-Shing; Tou, Janet C; Reiss-Bubenheim, Debra A; Hill, Esther L; Liittschwager, Kurt W; Girten, Beverly E; Pena-Yewkukhiw, Eugenia

2012-09-01

402

Predictability of the tropical atmosphere  

NASA Technical Reports Server (NTRS)

An examination of the deterministic predictability for tropics and middle-latitudes separately indicates that the theoretical upper limit of deterministic predictability for low latitudes is shorter than that for middle latitudes. Variability of time averages in low latitudes is mainly determined by the location and intensity of the large-scale Hadley and Walker circulations. Since these are largely influenced by the slowly varying boundary conditions of sea surface temperature and soil moisture, and since synoptic instabilities are not strong enough to change drastically the large scale flow, there is larger potential for predictability of monthly and seasonal means in low latitudes. It is conjectured that for short and medium range deterministic prediction, a prescribed diabatic heating field due to moist convection may be more useful than their explicit calculation from the evolving flow.

Shukla, J.

1981-01-01

403

Tropical medicine: Telecommunications and technology transfer  

NASA Technical Reports Server (NTRS)

The potential for global outbreaks of tropical infectious diseases, and our ability to identify and respond to such outbreaks is a major concern. Rapid, efficient telecommunications is viewed as part of the solution to this set of problems - the means to link a network of epidemiological field stations via satellite with U.S. academic institutions and government agencies, for purposes of research, training in tropical medicine, and observation of and response to epidemic emergencies. At a workshop, telecommunications and technology transfer were addressed and applications of telecommunications technology in long-distance consultation, teaching and disaster relief were demonstrated. Applications in teaching and consultation in tropical infectious diseases is discussed.

Legters, Llewellyn J.

1991-01-01

404

The hydrology of the humid tropics  

NASA Astrophysics Data System (ADS)

Hydrological processes in the humid tropics differ from other regions in having greater energy inputs and faster rates of change, including human-induced change. Human influences on population growth, land use and climate change will profoundly influence tropical hydrology, yet understanding of key hydrological interactions is limited. We propose that efforts to collect tropical data should explicitly emphasize characterizing moisture and energy fluxes from below the ground surface into the atmosphere. Research needs to chiefly involve field-based characterizations and modelling of moisture cycling and catchment processes, as well as long-term data acquisition and organization.

Wohl, Ellen; Barros, Ana; Brunsell, Nathaniel; Chappell, Nick A.; Coe, Michael; Giambelluca, Thomas; Goldsmith, Steven; Harmon, Russell; Hendrickx, Jan M. H.; Juvik, James; McDonnell, Jeffrey; Ogden, Fred

2012-09-01

405

Water Table Dynamics in a Tropical Peatland  

NASA Astrophysics Data System (ADS)

The soils of tropical peat forests store large amounts of carbon, which is susceptible to release by oxidation when these soils are drained. Therefore, fluctuations in water table depth are an important control on carbon sequestration and release in tropical peat soils. We present throughfall and water table observations using tipping bucket rain gauges and well piezometers along transects in a tropical peat forest in the Belait district of Brunei Darussalam, and provide time-frequency analysis of fluctuations in water table depth with rainfall.

Cobb, A.; Gandois, L.; Abu Salim, K.; Harvey, C.

2010-12-01

406

Tropical treeline dendroclimatology in Mexico  

NASA Astrophysics Data System (ADS)

Dendroclimatology in tropical areas is a relatively new enterprise, and extreme care is needed to provide quantitative calibration against instrumental data. Multi-century tree-ring records were recently developed from Pinus hartwegii trees growing at high elevation on Nevado de Colima, in the middle of the North American Monsoon region (Biondi, F. 2001. Ambio 30: 162-166). We present here three ongoing studies aimed at achieving the best possible calibration of tree growth response to climatic forcing. First, an automated weather station was installed in May 2001 within the forest where tree core samples were collected (3760 m elevation, 19°34.778' N latitude, 103°37.180' W longitude). Meteorological patterns are discussed in terms of atmospheric pressure, incoming solar radiation, air and soil temperature, relative humidity, soil moisture, wind speed and direction, and precipitation. Time scales range from hourly to seasonal, and shed light on variability of water supply at treeline in the tropics of North America. Second, automated electronic sensors for recording tree growth at half-hour intervals were installed at two sites located within a 1-km radius from the weather station. Data from this intensive monitoring experiment help define the length of the timberline growing season, are used to quantify the relationship with weather patterns at multiple time scales, and can test the response of annual tree growth to June precipitation. Third, monthly precipitation data for about 150 stations in Mexico were used to quantify spatio-temporal differences in the North American Monsoon region. Geostatistical techniques were applied to three indices of monsoon precipitation, namely the standardized difference between April and May, May and June, June and July precipitation. This objective classification of monsoon-affected land areas provides a useful backdrop for the evaluation of past changes in water cycle variability at the Nevado de Colima study area.

Biondi, F.

2003-04-01

407

The role of rodents in the ecology of Ixodes ricinus and associated pathogens in Central and Eastern Europe  

PubMed Central

Rodents comprise more species than any other mammal order. Most rodents are considered keystone species in their ecological communities, hence the survival of many other species in the ecosystem depend on them. From medical point of view, this is particularly important for rodent-dependent pathogens. In the particular case of tick-borne diseases, rodents are important as hosts for vector ticks and as reservoir hosts (Lyme borreliosis, human granulocytic anaplasmosis, Crimean-Congo hemorrhagic fever, Tick-borne relapsing fevers, tick-borne rickettsioses, babesiosis). Community and population ecology of rodents was shown to be correlated with disease ecology in the case of many tick-borne diseases. In Eastern Europe, several adult hard-tick species use rodents as their principal hosts: Ixodes apronophorus, I. crenulatus, I. laguri, I. redikorzevi, I. trianguliceps. However, the majority of ticks feeding on rodents are immature stages of ticks which as adults are parasitic on larger mammals. Larvae and nymphs of Ixodes ricinus, the most abundant and medically important tick from Europe, are commonly found on rodents. This is particularly important, as many rodents are synanthropic and, together with other micromammals and birds are often the only available natural hosts for ticks in urban environments. This work reviews the correlated ecology of rodents and I. ricinus.

Mihalca, Andrei D.; Sandor, Attila D.

2013-01-01

408

Biological sources and sinks of methane in tropical habitats and tropical atmospheric chemistry. Doctoral thesis  

SciTech Connect

The contents of this study include: two methods for measuring methane emission from a tropical lake; methane emission by bubbling from Gatun Lake, Panama; methane emission from wetlands in central Panama; consumption of atmospheric methane in soils of central Panama: effects of agricultural development; a seasonal study of soil-atmosphere methane, carbon dioxide, and 222Rn flux in a tropical moist forest; and the effects of tropical deforestation on global and regional atmospheric chemistry.

Keller, M.M.

1990-01-01

409

Molecular epidemiology of Orientia tsutsugamushi in chiggers and ticks from domestic rodents in Shandong, northern China  

PubMed Central

Background Scrub typhus is endemic to a 13,000,000-km2 area of the Asia-Pacific region, and causes an annual incidence of 1 million people. The mortality rate of scrub typhus ranges from 6.1% to 25% in Southeast Asia. Natural infection of Orientia tsutsugamushi has been identified in domestic rodents in Shandong Province. However, infestation of chiggers and ticks on the domestic rodents and prevalence and genotypes of O. tsutsugamushi in these Acarina remain unclear. Methods During September 2010 to March 2012, 3134 chiggers and 89 ticks were collected from domestic rodents captured in three counties of Shandong Province. We amplified and sequenced the 56-kDa type-specific antigen gene of O. tsutsugamushi from DNA samples of these Acarina and designated to genotype according to sequence analysis. Results Overall, the infestation rate of chiggers on domestic rodents was 17.0%, and the chigger index was 5.38. The infestation rate of ticks on rodents was 3.1%. Natural infection of O. tsutsugamushi was found in Leptotrombidium taishanicum, L. linhuaikongense, L. intermedium, L. scutellare, L. palpale, and Ixodes spp., the minimum positive rates of which were 5.9%, 3.2%, 1.2%, 0.8%, 0.8%, and 2.2%, respectively. Kawasaki-like genotypes were predominant in chiggers and ticks on domestic rodents, which were detected from L. taishanicum, L. intermedium, L. scutellare, L. palpale, and Ixodes spp. Shimokoshi-like genotype was detected from L. palpale. Conclusions In the present study we investigated the infestation of chiggers and ticks on domestic rodents in Shandong Province, and identified the prevalence and genotypes of O. tsutsugamushi in the Acarina. Infestation of vector chiggers in domestic rodents, prevalence of O. tsutsugamushi in infested chiggers, and high nucleotide homologies among the O. tsutsugamushi sequences from the Acarina, their animal hosts and scrub typhus patients, implied that domestic rodents may play an important role in the transmission of scrub typhus in Shandong, China. Further studies are needed to verify the vector significance of chiggers and ticks that tested positive for O. tsutsugamushi, and to assess the risk of human exposure to chiggers and ticks on domestic rodents.

2013-01-01

410

Do Tropical Cyclones Intensify by WISHE.  

National Technical Information Service (NTIS)

In this paper we seek and obtain a basic understanding of tropical cyclone intensification in three dimensions when precipitation and evaporative- cooling (warm rain) processes are included. Intensification with warm rain physics included is found to be d...

J. Persing M. T. Montgomery N. Van Sang R. K. Smith

2009-01-01

411

Tropical Storm Gilma in Eastern Pacific  

NASA Video Gallery

An animation of satellite observations shows the progression of Tropical Storm Gilma from August 7-10, 2012, along the coast of the Eastern Pacific Ocean. This visualization was created by the NASA...

412

Tropical Deforestation in the Bolivian Amazon  

NASA Technical Reports Server (NTRS)

Landsat satellite images from the mid-1980s and early 1990s were used to map tropical forest extent and deforestation in approximately 800,000 sq km of Amazonian Bolivia. Forest cover extent, including tropical deciduous forest, totalled 472,000 sq km while the area of natural non-forest formations totalled 298,000 sq km. The area deforested totalled 15,000 sq km in the middle 1980s and 28,800 sq km by the early 1990s. The rate of tropical deforestation in the >1,000 mm/y precipitation forest zone of Bolivia was 2,200 sq km/y from 1985-1986 to 1992-1994. We document a spatially-concentrated "deforestation zone" in Santa Cruz Department where >60% of the Bolivian deforestation is occurring at an accelerating rate in areas of tropical deciduous dry forest.

Tucker, Compton J.; Steininger, Marc K.; Townshend, John R. G.; Killeen, Timothy R.; Desch, Arthur

2000-01-01

413

GOES video of Tropical Storm Andrea  

NASA Video Gallery

This NOAA GOES-East satellite animation shows the development of System 91L into Tropical Storm Andrea over the course of 3 days from June 4 to June 6, just after Andrea was officially designated a...

414

Source of microbaroms from tropical cyclone waves  

NASA Astrophysics Data System (ADS)

Microbaroms are continuous infrasonic signals with a dominant frequency around 0.2 Hz produced by ocean surface waves. Monitoring stations around the globe routinely detect strong microbaroms in the lee of tropical cyclones. We utilize a parametric wind model and a spectral wave model to construct the tropical cyclone wave field and a theoretical acoustic source model to describe the intensity, spatial distribution, and dynamics of microbarom sources. This approach excludes ambient wave conditions and facilitates a parametric analysis to elucidate the source mechanism within the storm. A stationary tropical cyclone produces the strongest microbarom signals at the center, where the waves generated by the cyclonic winds converge. As the tropical cyclone moves forward, the converging wave field becomes less coherent and lags and expands behind the storm center. The models predict a direct relation between the storm forward speed and the location of maximum microbarom source intensity consistent with the infrasonic observations from Hurricane Felicia 2009 in the North Central Pacific.

Stopa, Justin E.; Cheung, Kwok Fai; GarcéS, Milton A.; Fee, David

2011-03-01

415

NOAA Paper: Tropical Cyclone Heat Potential  

NSDL National Science Digital Library

At this website, NOAA's Physical Oceanography Division illustrates its research dealing with the predictions of sudden tropical cyclone intensification through the monitoring of the upper ocean thermal structure. Students can learn about the utilization of a two-layer reduced gravity ocean model to determine the relationship between the dynamic height and the mass field of the ocean. Scientists can find out how, through the examination of seven tropical cyclone basins, the division found in an association between the tropical cyclone intensity and a raise in the value of tropical cyclone heat potentials (TCHP). After viewing the examples of the intensification for three hurricanes and one typhoon, users can find daily maps of the latest TCHP, sea surface temperatures, sea height anomalies, and more. Scientists looking for long term statistics can find weekly maps and data from October 1992 to the present.

416

Tropical Cyclone Jack in Satellite 3-D  

NASA Video Gallery

This 3-D flyby from NASA's TRMM satellite of Tropical Cyclone Jack on April 21 shows that some of the thunderstorms were shown by TRMM PR were still reaching height of at least 17 km (10.5 miles). ...

417

Have we overstated the tropical biodiversity crisis?  

PubMed

Tropical forests are the most biologically diverse and ecologically complex of terrestrial ecosystems, and are disappearing at alarming rates. It has long been suggested that rapid forest loss and degradation in the tropics, if unabated, could ultimately precipitate a wave of species extinctions, perhaps comparable to mass extinction events in the geological history of the Earth. However, a vigorous debate has erupted following a study by Wright and Muller-Landau that challenges the notion of large-scale tropical extinctions, at least over the next century. Here, I summarize this controversy and describe how the debate is stimulating a serious examination of the causes and biological consequences of future tropical deforestation. PMID:17011069

Laurance, William F

2007-02-01

418

Tropical Storm Wali Seen by GOESWest  

NASA Video Gallery

This animation of infrared and visible imagery from NOAA's GOES-West satellite from July 15 to 18 shows the birth of Tropical Storm Wali southeast of the Big Island of Hawaii on July 17. Credit: NA...

419

[Profile of tropical diseases in Portugal].  

PubMed

The increased incidence of Imported Tropical Diseases in Portugal is correlated to a recent higher standard of living, influence of media and a consequent expansion of tourism, and above all to the close relationship existing between Portugal and Africa. The number and pathology (parasitic diarrhoeas, protozoal and helminthic infections) of in-patients with Tropical Diseases at the Unidade de Doenças Infecciosas, Parasitárias e de Medicina Tropical (UDIP-MT) were described, with special emphasis on Malaria (155 in-patients during the period from 1989 to 1993) and on Sleeping Sickness, where Eflornitin (DFMO) was for the first time used in Portugal. Finally, the impact of HIV epidemic on incidence and different clinical presentations of parasitic and other tropical pathology was also evaluated. PMID:9005704

Ventura, F A

1996-01-01

420

Dynamic Properties of Functional Connectivity in the Rodent  

PubMed Central

Abstract Functional connectivity mapping with resting-state magnetic resonance imaging (MRI) has become an immensely powerful technique that provides insight into both normal cognitive function and disruptions linked to neurological disorders. Traditionally, connectivity is mapped using data from an entire scan (minutes), but it is well known that cognitive processes occur on much shorter time scales (seconds). Recent studies have demonstrated that the correlation between the blood oxygenation level-dependent (BOLD) MRI signal from different areas varies over time, motivating a further exploration of these fluctuations in apparent connectivity. However, it has also been shown that similar changes in correlation can arise when the timing relationships between voxels are randomized (Handwerker et al., 2012). In this work, we show that functional connectivity in the anesthetized rat exhibits dynamic properties that are similar to those previously observed in awake humans (Chang and Glover, 2010) and anesthetized monkeys (Hutchison et al., 2012). Sliding window correlation between BOLD time courses obtained from bilateral cortical and subcortical regions of interest results in periods of variable positive and negative correlation for most pairs of areas except homologous areas in opposite hemispheres, which exhibit a primarily positive correlation. A comparison with sliding window correlation of randomly matched time courses suggests that with the exception of homologous areas and sensorimotor connections, the dynamics cannot be distinguished from random fluctuations in correlation over time, supporting the idea that some of these dynamic patterns may be due to inherent properties of the signal rather than variations in neural coherence. Within the pairs of areas where the dynamics are most different from those of randomly matched time courses, ten common patterns of connectivity are identified, and their occurrence as a function of time is plotted for all animals. The observation of time-varying correlation in the rodent model will facilitate the future multimodal experiments needed to determine whether the changes in apparent connectivity are linked to underlying neural variability.

Magnuson, Matthew E.; Pan, Wen-Ju; Willis, Martha; Thompson, Garth J.

2013-01-01

421

Dynamics of INSL3 peptide expression in the rodent testis.  

PubMed

The Leydig cell-specific factor insulin-like peptide 3 (INSL3) is involved in testicular descent during embryo development, and has been suggested to regulate spermatogenesis and bone metabolism in the adult. Using a new, sensitive assay specific for rodent INSL3, we have mapped the secretion of INSL3 into peripheral blood in mice and during postnatal male rat development (in female rats, circulating INSL3 is at the level of detection). Maximum INSL3 is measured at Postnatal Day (PD) 40 in the rat and decreases to a significantly lower, stable value by PD60, indicating an "overshoot" effect in the establishment of Leydig cell functionality during the first wave of spermatogenesis. Aging rats ( approximately 24 mo) have markedly reduced circulating INSL3 levels, as do humans. Treatment of young adult rats with ethane dimethylsulfonate (EDS) leads to loss of mature Leydig cells and no detectable INSL3 in peripheral blood. INSL3 can be detected first at Day 27 after EDS treatment, returning to near normal levels by Day 37. Both primary rat Leydig cells and the mouse MA-10 tumor cell line secrete substantial amounts of INSL3 into the culture media in a constitutive manner, unregulated by common effectors, including hCG. Analysis of different testicular fluid compartments shows highest INSL3 concentration in the interstitial fluid (391.4 +/- 47.8 ng/ml). However, INSL3 evidently traverses the blood-testis barrier to enter the seminiferous compartment, rete testis, and epididymis in sufficient concentration to be able to address the specific INSL3 receptors (RXFP2) on post-meiotic germ cells and in the epididymis. PMID:19420383

Anand-Ivell, Ravinder; Heng, Kee; Hafen, Bettina; Setchell, Brian; Ivell, Richard

2009-09-01

422

Dual-energy micro-CT of the rodent lung  

PubMed Central

The purpose of this work is to investigate the use of dual-energy micro-computed tomography (CT) for the estimation of vascular, tissue, and air fractions in rodent lungs using a postreconstruction three material decomposition method. Using simulations, we have estimated the accuracy limits of the decomposition for realistic micro-CT noise levels. Next, we performed experiments involving ex vivo lung imaging in which intact rat lungs were carefully removed from the thorax, injected with an iodine-based contrast agent, and then inflated with different volumes of air (n = 2). Finally, we performed in vivo imaging studies in C57BL/6 mice (n = 5) using fast prospective respiratory gating in end inspiration and end expiration for three different levels of positive end expiratory pressure (PEEP). Before imaging, mice were injected with a liposomal blood pool contrast agent. The three-dimensional air, tissue, and blood fraction maps were computed and analyzed. The results indicate that separation and volume estimation of the three material components of the lungs are possible. The mean accuracy values for air, blood, and tissue were 93, 93, and 90%, respectively. The absolute accuracy in determining all fraction materials was 91.6%. The coefficient of variation was small (2.5%) indicating good repeatability. The minimum difference that we could detect in material fractions was 15%. As expected, an increase in PEEP levels for the living mouse resulted in statistically significant increases in air fractions at end expiration but no significant changes at end inspiration. Our method has applicability in preclinical pulmonary studies where changes in lung structure and gas volume as a result of lung injury, environmental exposures, or drug bioactivity would have important physiological implications.

Guo, X.; Clark, D.; Johnston, S. M.; Marshall, C. D.; Piantadosi, C. A.

2012-01-01

423

NASA Rodent Foodbar: Long Term Effects in Swiss Webster Mice  

NASA Technical Reports Server (NTRS)

Swiss Webster male and female mice (150 of each) were fed NASA Rodent Foodbar for more than 110 days to test the diet's nutritional adequacy for use in future long-term studies aboard the International Space Station. Mice were grouped three to a cage (one cage = one sample) and cages were assigned to either Foodbar or Purina Chow #5001 (control) diet groups. Body weights, food intake, and water intake were obtained throughout the study. There were no significant differences in body weights between male Foodbar fed and Chow fed males (p=0.58), and at 15 weeks into the female mouse study there appear to be no significant body weight differences. Both male and female Foodbar fed groups consumed more food and less water than their Chow controls, both factors thought to be attributable to the high moisture content of the Foodbars (26% versus 10% for Chow). All differences in gross food and water consumption had p-values of less than 0.01. When food and water intake were adjusted for the moisture content in the food, both male and female Foodbar fed animals consumed less food, but still had a lower water intake rate than their controls. (p is less than 0.01). Preliminary analysis on blood samples from male and female halfway point dissections suggests differences in glucose and fat metabolism. In both male and female Foodbar fed animals, blood glucose values were significantly lower (p is less than 0.01) but there were no significant differences in cholesterol levels (p=0.51). In Foodbar fed females, triglycerides were significantly higher (p is less than 0.01). These data suggest that Foodbars allow for normal growth in Swiss Webster mice, but affect some blood chemistry parameters.

Santiago, D. L.; Yu, D. S.; Naficy, N. H.; Roghani, P. M.; Dalton, B. P.; Barrett, J. E.; Dalton, Bonnie (Technical Monitor)

2001-01-01

424

Dual-energy micro-CT of the rodent lung.  

PubMed

The purpose of this work is to investigate the use of dual-energy micro-computed tomography (CT) for the estimation of vascular, tissue, and air fractions in rodent lungs using a postreconstruction three material decomposition method. Using simulations, we have estimated the accuracy limits of the decomposition for realistic micro-CT noise levels. Next, we performed experiments involving ex vivo lung imaging in which intact rat lungs were carefully removed from the thorax, injected with an iodine-based contrast agent, and then inflated with different volumes of air (n = 2). Finally, we performed in vivo imaging studies in C57BL/6 mice (n = 5) using fast prospective respiratory gating in end inspiration and end expiration for three different levels of positive end expiratory pressure (PEEP). Before imaging, mice were injected with a liposomal blood pool contrast agent. The three-dimensional air, tissue, and blood fraction maps were computed and analyzed. The results indicate that separation and volume estimation of the three material components of the lungs are possible. The mean accuracy values for air, blood, and tissue were 93, 93, and 90%, respectively. The absolute accuracy in determining all fraction materials was 91.6%. The coefficient of variation was small (2.5%) indicating good repeatability. The minimum difference that we could detect in material fractions was 15%. As expected, an increase in PEEP levels for the living mouse resulted in statistically significant increases in air fractions at end expiration but no significant changes at end inspiration. Our method has applicability in preclinical pulmonary studies where changes in lung structure and gas volume as a result of lung injury, environmental exposures, or drug bioactivity would have important physiological implications. PMID:22427526

Badea, C T; Guo, X; Clark, D; Johnston, S M; Marshall, C D; Piantadosi, C A

2012-05-15

425

Assays of homeopathic remedies in rodent behavioural and psychopathological models.  

PubMed

The first part of this paper reviews the effects of homeopathic remedies on several models of anxiety-like behaviours developed and described in rodents. The existing literature in this field comprises some fifteen exploratory studies, often published in non-indexed and non-peer-reviewed journals. Only a few results have been confirmed by multiple laboratories, and concern Ignatia, Gelsemium, Chamomilla (in homeopathic dilutions/potencies). Nevertheless, there are some interesting results pointing to the possible efficacy of other remedies, and confirming a statistically significant effect of high dilutions of neurotrophic molecules and antibodies. In the second part of this paper we report some recent results obtained in our laboratory, testing Aconitum, Nux vomica, Belladonna, Argentum nitricum, Tabacum (all 5CH potency) and Gelsemium (5, 7, 9 and 30CH potencies) on mice using ethological models of behaviour. The test was performed using coded drugs and controls in double blind (operations and calculations). After an initial screening that showed all the tested remedies (except for Belladonna) to have some effects on the behavioural parameters (light-dark test and open-field test), but with high experimental variability, we focused our study on Gelsemium, and carried out two complete series of experiments. The results showed that Gelsemium had several effects on the exploratory behaviour of mice, which in some models were highly statistically significant (p < 0.001), in all the dilutions/dynamizations used, but with complex differences according to the experimental conditions and test performed. Finally, some methodological issues of animal research in this field of homeopathy are discussed. The "Gelsemium model" - encompassing experimental studies in vitro and in vivo from different laboratories and with different methods, including significant effects of its major active principle gelsemine - may play a pivotal rule for investigations on other homeopathic remedies. PMID:19945676

Bellavite, Paolo; Magnani, Paolo; Marzotto, Marta; Conforti, Anita

2009-10-01

426

Dynamic properties of functional connectivity in the rodent.  

PubMed

Functional connectivity mapping with resting-state magnetic resonance imaging (MRI) has become an immensely powerful technique that provides insight into both normal cognitive function and disruptions linked to neurological disorders. Traditionally, connectivity is mapped using data from an entire scan (minutes), but it is well known that cognitive processes occur on much shorter time scales (seconds). Recent studies have demonstrated that the correlation between the blood oxygenation level-dependent (BOLD) MRI signal from different areas varies over time, motivating a further exploration of these fluctuations in apparent connectivity. However, it has also been shown that similar changes in correlation can arise when the timing relationships between voxels are randomized (Handwerker et al., 2012 ). In this work, we show that functional connectivity in the anesthetized rat exhibits dynamic properties that are similar to those previously observed in awake humans (Chang and Glover, 2010 ) and anesthetized monkeys (Hutchison et al., 2012 ). Sliding window correlation between BOLD time courses obtained from bilateral cortical and subcortical regions of interest results in periods of variable positive and negative correlation for most pairs of areas except homologous areas in opposite hemispheres, which exhibit a primarily positive correlation. A comparison with sliding window correlation of randomly matched time courses suggests that with the exception of homologous areas and sensorimotor connections, the dynamics cannot be distinguished from random fluctuations in correlation over time, supporting the idea that some of these dynamic patterns may be due to inherent properties of the signal rather than variations in neural coherence. Within the pairs of areas where the dynamics are most different from those of randomly matched time courses, ten common patterns of connectivity are identified, and their occurrence as a function of time is plotted for all animals. The observation of time-varying correlation in the rodent model will facilitate the future multimodal experiments needed to determine whether the changes in apparent connectivity are linked to underlying neural variability. PMID:23106103

Keilholz, Shella D; Magnuson, Matthew E; Pan, Wen-Ju; Willis, Martha; Thompson, Garth J

2013-01-01

427

Rodent neurotoxicity bioassays for screening contaminated Great Lakes fish  

SciTech Connect

Standard laboratory rat neurotoxicity protocols were used to study the consequences resulting from the consumption of walleye (Stizostedion vitreum), whitefish (Coregonus clupeaformis), and lake trout (Salvelinus namaycush) from Lake Superior (LS) and the consumption of carp (Cyprinus carpio) from Little Lake Butte des Morte (LLBM) near Oshkosh, Wisconsin, USA. Two 90-d subchronic studies are described, including a 45-d exposure to fish diets using male Sprague-Dawley hooded rats, and a 90-d exposure to fish diets using female rats of the same species. Behavioral alterations were tested using a battery of behavioral tests. In addition, pharmacologic challenges using apomorphine and D-amphetamine were administered to the rats to reveal latent neurotoxic effects. Cumulative fish consumption data were recorded daily, weight gain recorded weekly, and behavior data collected prior to exposure, and on days 7, 14, 55 {+-} 2, 85 {+-} 2. Motor activity data were collected on days 30 {+-} 2, 60 {+-} 2, and 90 {+-} 2 of the feeding protocols. Brain tissue from rodents fed these fish were subsequently analyzed for either mercury (Hg) or polychlorinated biphenyls (PCB). Mercury concentrations were increased in the brains of the walleye-fed rats, and PCB concentrations ranged from 0.5 nl/L to 10 nl/L in the brains of rats fed carp from LLBM, a Lake Michigan tributary. Adult male rats fed LLBM carp for 45 d exhibited the greatest behavior responses to the dopaminergic agonist apomorphine on the accelerating rotarod, although these differences were not significant. The 90-d exposure of LS walleye or Hg-spiked LS walleye resulted in behavior alterations on tactile startle response and second footsplay. D-Amphetamine challenge caused changes in tactile startle response, second footsplay, and accelerating rotarod performance after consuming walleye diets. Rats fed LLBM carp had altered behavioral responses to apomorphine on the accelerating rotarod.

Beattie, M.K.; Hoffman, R. [Univ. of Minnesota, Duluth, MN (United States); Gerstenberger, S. [Univ. of Illinois, Urbana, IL (United States). Dept. of Veterinary Biosciences; Dellinger, J.A. [Medical Coll. of Wisconsin, Milwaukee, MI (United States). Dept. of Preventive Medicine

1996-03-01

428

Lung imaging in rodents using dual energy micro-CT  

NASA Astrophysics Data System (ADS)

Dual energy CT imaging is expected to play a major role in the diagnostic arena as it provides material decomposition on an elemental basis. The purpose of this work is to investigate the use of dual energy micro-CT for the estimation of vascular, tissue, and air fractions in rodent lungs using a post-reconstruction three-material decomposition method. We have tested our method using both simulations and experimental work. Using simulations, we have estimated the accuracy limits of the decomposition for realistic micro-CT noise levels. Next, we performed experiments involving ex vivo lung imaging in which intact lungs were carefully removed from the thorax, were injected with an iodine-based contrast agent and inflated with air at different volume levels. Finally, we performed in vivo imaging studies in (n=5) C57BL/6 mice using fast prospective respiratory gating in endinspiration and end-expiration for three different levels of positive end-expiratory pressure (PEEP). Prior to imaging, mice were injected with a liposomal blood pool contrast agent. The mean accuracy values were for Air (95.5%), Blood (96%), and Tissue (92.4%). The absolute accuracy in determining all fraction materials was 94.6%. The minimum difference that we could detect in material fractions was 15%. As expected, an increase in PEEP levels for the living mouse resulted in statistically significant increases in air fractions at end-expiration, but no significant changes in end-inspiration. Our method has applicability in preclinical pulmonary studies where various physiological changes can occur as a result of genetic changes, lung disease, or drug effects.

Badea, C. T.; Guo, X.; Clark, D.; Johnston, S. M.; Marshall, C.; Piantadosi, C.

2012-02-01

429

Objective classification of historical tropical cyclone intensity  

NASA Astrophysics Data System (ADS)

Preinstrumental records of historical tropical cyclone activity require objective methods for accurately categorizing tropical cyclone intensity. Here wind force terms and damage reports from newspaper accounts in the Lesser Antilles and Jamaica for the period 1795-1879 are compared with wind speed estimates calculated from barometric pressure data. A total of 95 separate barometric pressure readings and colocated simultaneous wind force descriptors and wind-induced damage reports are compared. The wind speed estimates from barometric pressure data are taken as the most reliable and serve as a standard to compare against other data. Wind-induced damage reports are used to produce an estimated wind speed range using a modified Fujita scale. Wind force terms are compared with the barometric pressure data to determine if a gale, as used in the contemporary newspapers, is consistent with the modern definition of a gale. Results indicate that the modern definition of a gale (the threshold point separating the classification of a tropical depression from a tropical storm) is equivalent to that in contemporary newspaper accounts. Barometric pressure values are consistent with both reported wind force terms and wind damage on land when the location, speed and direction of movement of the tropical cyclone are determined. Damage reports and derived wind force estimates are consistent with other published results. Biases in ships' logbooks are confirmed and wind force terms of gale strength or greater are identified. These results offer a bridge between the earlier noninstrumental records of tropical cyclones and modern records thereby offering a method of consistently classifying storms in the Caribbean region into tropical depressions, tropical storms, nonmajor and major hurricanes.

Chenoweth, Michael

2007-03-01

430

High hydrostatic pressure processing of tropical fruits.  

PubMed

Interest in the nonthermal method of high hydrostatic pressure (HHP) for food preservation has increased recently due to the possibility of inactivating microorganisms and enzymes while maintaining product sensorial and nutritional properties. This work deals with HHP use for the preservation of tropical fruit products. HHP is shown to be a practical approach to obtaining high-quality tropical fruit products that are both nutritive and safe. PMID:20233363

Lopes, Maria Lúcia M; Valente Mesquita, Vera L; Chiaradia, Ana Cristina N; Fernandes, Antônio Alberto R; Fernandes, Patricia M B

2010-02-01

431

Application of remote sensing in tropical forests  

NASA Technical Reports Server (NTRS)

Cloud cover in tropical humid forests can pose serious operational constraints on Landsat TM and SPOT HRV instrumentation, given their respective orbital frequencies of 16 and 26 days. SAR data intrinsically precludes such problems; the increase of data acquisition frequency to daily rates, as with the NOAA AVHRR instrument, also bears consideration. It is deemed essential that SAR data-related research be expedited, in order to ascertain inherent SAR information for tropical forests in a timely and cost-effective manner.

Joyce, Armond T.; Luvall, J. C.; Sever, T.

1990-01-01

432

Monitoring tropical environments with Space Shuttle photography  

NASA Technical Reports Server (NTRS)

Orbital photography from the Space Shuttle missions (1981-88) and earlier manned spaceflight programs (1962-1975) allows remote sensing time series to be constructed for observations of environmental change in selected portions of the global tropics. Particular topics and regions include deforestation, soil erosion, supersedimentation in streams, lacustrine, and estuarine environments, and desertification in the greater Amazon, tropical Africa and Madagascar, South and Southeast Asia, and the Indo-Pacific archipelagoes.

Helfert, Michael R.; Lulla, Kamlesh P.

1989-01-01

433

Tropical deforestation in the Bolivian Amazon  

Microsoft Academic Search

Landsat satellite images from the mid-1980s and early 1990s were used to map tropical forest extent and deforestation in approximately 800,000 km2 of Amazonian Bolivia. Forest cover extent, including tropical deciduous forest, totaled 472,000 km2 while the area of natural non-forest formation totaled 298,000 km2. The area deforested totaled 15,000 km2 in the middle 1980s and 28,800 km2 by the

Compton J. Tucker; Marc K. Steininger; John R. Townshend; Timothy R. Killeen; Arthur Desch

2000-01-01

434

Dermatologic Presentations of Tropical Diseases in Travelers  

Microsoft Academic Search

Dermatoses are one of the three most common presenting health care problems in returning travelers. The spectrum of travel-related\\u000a dermatoses is broad, and includes tropical, cosmopolitan, and environmental skin diseases. Bacterial infections are the main\\u000a cause of skin consultations in returning travelers. Most of these infections are not specific to the tropics and are the consequences\\u000a of arthropod bites. Conversely,

Gentiane Monsel; Eric Caumes

2010-01-01

435

Observed Climate Properties of Tropical Precipitating Convection  

NASA Technical Reports Server (NTRS)

Conflicting theories about the contribution of convective systems to cloud feedback highlight the need for observational constraints on the properties of these storms. The NASA Tropical Rainfall Measuring Mission (TRMM) satellite provides unprecedented information on the hydrological properties and energetics of tropical convection. We present an analysis of almost 9,000 TRMM storms, focusing on how convection strength affects storm cloud properties and rainfall, and what this implies for the opposing "adaptive iris" and "thermostat" hypotheses.

DelGenio, Anthony

2002-01-01

436

Tropical Homegardens in Bangladesh: Characteristics and Sustainability  

Microsoft Academic Search

\\u000a Homegardens are a species-rich and complex multistrata agroecosystem in the tropics. Those traditionally managed farming systems\\u000a are of immense value in rural socioeconomy. The basic functions of tropical homegardens are generation of products for subsistence\\u000a and earning cash income in areas with good market structure. Homegardens also provide a range of environmental services. In\\u000a Bangladesh at least 20 million people

Mahbubul Alam

437