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1

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

2013-05-06

2

Daily variations in plasma melatonin and melatonin receptor (MT1), PER1 and CRY1 expression in suprachiasmatic nuclei of tropical squirrel, Funambulus pennanti.  

PubMed

The suprachiasmatic nucleus (SCN) plays a major role in photoperiodic regulation of seasonal functions by modulating the melatonin signal. To date no report exists regarding the role of the ambient photoperiod in the regulation of melatonin receptor MT1 and clock gene (PER1 and CRY1) expression in the SCN of any tropical rodent that experiences the least variation in the photoperiod. We noted the expression of MT1, PER1 and CRY1 in the SCN of a tropical squirrel, Funambulus pennanti, along with the plasma level of melatonin over 24 h during the reproductively active (summer) and inactive (winter) phases. The seasonal day length affected the peripheral melatonin, which was inversely related with the MT1 expression in the SCN. The timing for peak expression of PER1 was the same in both phases, while the decline in PER1 expression was delayed by 4 h during the inactive phase. The CRY1 peak advanced by 4 h during the active phase, while the interval between the peak and decline of CRY1 remained the same in both phases. It can be suggested that seasonally changing melatonin levels modulate MT1 expression dynamics in the SCN, altering its functional state, and gate SCN molecular "clock" gene profiles through changes in PER/CRY expression. Such a regulation is important for photo-physiological adaptation (reproduction/immunity) in seasonal breeders. PMID:23852344

Gupta, Sameer; Haldar, Chandana; Singh, Sarika

2013-07-13

3

Melatonin blocks dexamethasone-induced immunosuppression in a seasonally breeding rodent Indian palm squirrel, Funambulus pennanti  

Microsoft Academic Search

In vivo effect of dexamethasone and melatonin on immunomodulation has been investigated by studying the lymphocyte proliferation to the mitogen Con A from various lymphoid tissues including bone marrow cells of a seasonally breeding rodent adult male F. pennanti during reproductively inactive phase (October to December). During this phase, animal faces the maximum challenges of the nature (hypothermic stress, scarcity

Chandana Haldar; Seema Rai; Rajesh Singh

2004-01-01

4

Melatonin blocks dexamethasone-induced immunosuppression in a seasonally breeding rodent Indian palm squirrel, Funambulus pennanti.  

PubMed

In vivo effect of dexamethasone and melatonin on immunomodulation has been investigated by studying the lymphocyte proliferation to the mitogen Con A from various lymphoid tissues including bone marrow cells of a seasonally breeding rodent adult male F. pennanti during reproductively inactive phase (October to December). During this phase, animal faces the maximum challenges of the nature (hypothermic stress, scarcity of food and shelter). Dexamethasone treatment (60 microg/day/squirrel) for 60 consecutive days significantly decreased the thymus and spleen activity. The lymphoid tissues mass, total leukocyte, lymphocyte count of peripheral blood, bone marrow and T-cell mediated immune function was also significantly suppressed following the dexamethasone treatment but treatment of melatonin (25 microg/squirrel/day) along with dexamethasone significantly restored the suppressed immune status in squirrels. Further, histological study of the thymus showed profound changes in the cellularity with a depletion of thymocytes in the cortex region of thymic lobules and increased in connective tissues and spindle cells. Melatonin treatment alone increased thymocytes density in thymic cortex, clearly suggesting that melatonin counteracted the experimentally induced immune stress by dexamethasone. Therefore, in nature during reproductively inactive phase of the squirrel a high level of melatonin was noted, that is required to combat nature's stress, which might have increased the internal level of corticoids. PMID:15219786

Haldar, Chandana; Rai, Seema; Singh, Rajesh

2004-06-01

5

Problems of rodent control in rural tropical areas  

PubMed Central

Rodent control strategies, techniques, and research needs in rural tropical environments are reviewed and discussed with special reference to Mastomys natalensis, the possible reservoir of Lassa fever in West Africa. Public health rodent problems are far more serious and widespread in rural tropical areas than in developed countries. In the latter, only the commensal rodents constitute a major problem, whereas in rural tropical areas, native semidomestic species also serve as disease reservoirs and sources of infection to man. The success of rodent control programmes in developed countries depends in large part on the willingness and ability of people and governments to spend relatively large sums on research and control, on an acquired intolerance of people to rats and disease, and on a substantial economic base. These prerequisites are not usually to be found in rural tropical areas. Consequently, the rodent control techniques and programme organizations of developed countries are not directly applicable to such areas, even though the principles are the same. For this reason, it is suggested that a well-funded, integrated research and control programme should be undertaken in a known Lassa fever area, stressing public education, personnel training, and environmental management as well as rodenticidal approaches.

Barnes, Allan M.

1975-01-01

6

Museum specimen data predict crop damage by tropical rodents  

PubMed Central

Museum collections constitute a massive store of information on biological diversity. We used museum specimen data to generate ecological niche models that provide predictions of geographic distributions of native rodent pest species and agricultural census data that summarize the geographic distribution of nine crops in the state of Veracruz, Mexico, as well as crop losses between planting and harvest. Herein, we show that crop damage is related significantly to the predicted presence of rodent species for seven of nine crops. Museum collections may thus provide important baseline information for designing land-use and agricultural pest-management programs.

Sanchez-Cordero, Victor; Martinez-Meyer, Enrique

2000-01-01

7

Lack of immunological responsiveness to photoperiod in a tropical rodent, Peromyscus aztecus hylocetes.  

PubMed

Non-tropical rodents undergo seasonal changes in immune function and disease. It has been hypothesized that seasonal fluctuations in immunity of non-tropical rodents are due to suppressed immune function during harsh winter conditions. A logical extension of this hypothesis is that seasonal changes in immunity should be reduced or absent in tropical rodents that do not experience marked seasonal fluctuations in environmental conditions; however this hypothesis remains to be tested. The present study tested the effects of photoperiod on humoral and cell-mediated immune function of male Aztec mice ( Peromyscus aztecus hylocetes). P. a. hylocetes were housed in long (L:D 16:8) or short days (L:D 8:16) for 10 weeks. Animals were then immunized with the antigen keyhole limpet hemocyanin (KLH). Serum anti-KLH immunoglobulin G (IgG) concentrations and splenocyte proliferation in response to the T-cell mitogen Concanavalin A were assessed. Short-day P. a. hylocetes did not display differences in reproductive or immune measures compared with long-day mice. Collectively, these results suggest that P. a. hylocetes are reproductively and immunologically non-responsive to photoperiod. This lack of immunological responsiveness is likely due to the relative seasonal stability of their environment compared with temperate zone species. PMID:12624655

Demas, G E; Nelson, R J

2003-02-12

8

Effect of logging on rodent scatter-hoarding dynamics in tropical forests: implications for plant recruitment.  

PubMed

The present study tested the hypothesis that logging affects the scatter-hoarding behavior of rodents, which, in turn, negatively affects the quantity and quality of Pouteria campechiana (Sapotaceae) seed dispersal. A series of seed stations was established in logged and unlogged forests of ejido Señor, Yucatan Peninsula, and comparisons were made between logged and unlogged forests in terms of: (i) seed removal; (ii) number of seeds hoarded; (iii) hoarding distance; and (iv) the number of recruits and the survival of hoarded seeds. The number of both hoarded and removed seeds was significantly higher in unlogged sites. Furthermore, the mean distance of hoarding was greater in unlogged compared with logged sites. Although recruitment and survival were present in both logged and unlogged sites, there were more surviving seedlings in unlogged sites. The data indicate that both the quantity and quality of seed dispersal are negatively affected by logging because of a change in the rodent scatter-hoarding dynamics. These changes suggest that plant-animal interactions are crucial to the understanding of the ecology and conservation of managed tropical forests. PMID:21645273

Gutiérrez-Granados, Gabriel

2011-06-01

9

Rodent Diversity in a Highly Degraded Tropical Landscape: Hong Kong, South China  

Microsoft Academic Search

The diverse ecological roles played by different rodent species mean that the loss of some species and superabundance of others\\u000a could potentially influence a wide range of ecological processes. Hong Kong (22° N, 114° E), with seven million people in\\u000a a land area of 1100 km2, could be considered a `worst case scenario' for the survival of mammalian diversity. Existing information on rodents

Kylie P. S. Chung; Richard T. Corlett

2006-01-01

10

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

11

Rodent Control  

ERIC Educational Resources Information Center

Strategies for rodent control in crop fields, threshing yards, and rural residential areas are presented together with an operational plan for implementing a program for rodent control at the national level. Training personnel in rodent control procedures and procedures for educating the public in the necessity for control are covered. (EC)

Indian Journal of Adult Education, 1975

1975-01-01

12

Temporal synergism of neurotransmitter affecting drugs and seasonal reproductive responses of Indian Palm Squirrel, Funambulus pennanti.  

PubMed

Daily injections of L-dihydroxyphenylalanine (L-DOPA, dopamine precursor) given 12 hour after 5-hydroxytryptophan (5-HTP, serotonin precursor) eliminated annual testicular regression in seasonally breeding sub-tropical Palm Squirrel that undergoes seasonal changes in responsiveness to day-length and humidity. Other temporal relations (L-DOPA given 0, 4, 8, 16 and 20 hours after 5-HTP administration) decreased/delayed the rate of regression and maintained the reproductive system at intermediate level. 12-hour-relation maintained full breeding condition (maximum gonad and accessory sex organs) unlike control, which exhibited complete atrophy of primary and accessory sex organs. It seems likely that these injections entrained the circadian serotonergic and dopaminergic oscillations and the interaction/phase relation of these two systems through their many circadian expressions (neural/hormonal) accounts for the seasonal interpretation of environmental factors. It is suggested that response in the present study is not a pharmacological effect of drugs but temporal synergism of neural activities affected the seasonality of reproduction as only 12-hour-relation of 5-HTP and L-DOPA maintained breeding activity during post reproductive phase of annual gonad cycle in Palm Squirrel. PMID:2357326

Chaturvedi, C M; Jaiwal, R

1990-01-01

13

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

14

Rodents And Other Gnawers.  

ERIC Educational Resources Information Center

Presents information about rodents and lagomorphs, including definitions and the characteristics of these animals. Contains teaching activities such as "Habitats for Hoppers,""Cartoon Gnawers," and "The Great Rodent Expedition." Reproducible handouts for two of the activities are provided. (TW)

Naturescope, 1986

1986-01-01

15

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

Microsoft Academic Search

The sporocarps of hypogeous and epigeous fungi are important dietary items for forest dwelling rodents in temperate and tropical\\u000a forests throughout the world. However, results of some pioneering works have demonstrated that fungi cannot be considered\\u000a as nutritionally high-quality food items for some mycophagous small rodents. According to these studies, when mycophagous\\u000a rodents feed on fungus, they showed a minimal

T. D’Alva; C. Lara; A. Estrada-Torres; C. Castillo-Guevara

2007-01-01

16

Social biology of rodents.  

PubMed

Herein, I summarize some basic components of rodent social biology. The material in this paper is summarized and condensed from a recent book "Rodent Societies: An Ecological and Evolutionary Perspective" edited by J. O. Wolff and P. W. Sherman (2007). I describe the four basic spacing patterns and illustrate how female territoriality is a function of offspring defense and male mating tactics are a function of female defensibility. The vulnerability of young to infanticide shapes female spacing and mating behavior. Food does not appear to be a defensible resource for rodents, except for those species that larder hoard nonperishable items such as seeds. Philopatry and the formation of kin groups result in genetic sub-structuring of the population, which in turn affects effective population size and genetic diversity. Dispersal is male biased and typically involves emigration from the maternal site to avoid female relatives and to seek unrelated mates. Scent marking is a major form of communication and is used in reproductive competition and to assess prospective mates, but it is also eavesdropped by predators to locate prey. Females do not appear to alter the sex ratio of litters in response to maternal condition but among arvicoline rodents daughters appear to be favored in spring and sons in autumn. Rodents are relatively monomorphic; however, females tend to be larger than males in the smallest species and smaller in the larger species. Predation risk results from an interaction among foraging time and vulnerability and in turn affects behavioral and life history characteristics. PMID:21396036

Wolff, Jerry O

2007-12-01

17

TECHNIQUES IN ASEPTIC RODENT SURGERY  

PubMed Central

Performing aseptic survival surgery in rodents can be challenging. This unit describes some basic principles to assist clinicians, researchers, and technicians in becoming proficient in performing aseptic rodent surgery.

Hoogstraten-Miller, Shelley L.; Brown, Patricia A.

2008-01-01

18

Tropical Belt  

NSDL National Science Digital Library

This lesson familiarizes learners with the term "tropical belt." First, learners locate the equator, Tropic of Cancer and Tropic of Capricorn on a map and trace these lines with a crayon. Learners also color in the locations of tropical rainforests. Next, learners cut along the colored lines of the Tropic of Cancer and Tropic of Capricorn. Educators can punch a hole at each end of this map and tie the ends together with yarn. Learners can wear the belt in class to remind themselves that rainforests are found near the equator or midsection of the Earth. This lesson includes extension ideas and is standards-based.

Sciences, California A.

2008-01-01

19

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

20

Invasive Rodent Eradication on Islands  

Microsoft Academic Search

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

GREGG HOWALD; C. JOSH DONLAN; JUAN PABLO GALVÁN; JAMES C. RUSSELL; JOHN PARKES; ARACELI SAMANIEGO; YIWEI WANG; DICK VEITCH; PIERO GENOVESI; MICHEL PASCAL; ALAN SAUNDERS; BERNIE TERSHY

2007-01-01

21

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

22

Tropical Rainforests.  

ERIC Educational Resources Information Center

|Presented is a summary of scientific knowledge about the rainforest environment, a tropical ecosystem in danger of extermination. Topics include the current state of tropical rainforests, the causes of rainforest destruction, and alternatives of rainforest destruction. (BT)|

Nigh, Ronald B.; Nations, James D.

1980-01-01

23

Rodent models of glaucoma  

PubMed Central

Glaucoma is a progressive, age-related optic neuropathy and a leading cause of irreversible blindness in the world. Animal models of glaucoma are essential to our continued efforts of elucidating the natural course of the disease and to developing therapeutic interventions to halt or reverse the progression of the condition. Over the past 10–15 years, rodents have become a popular model organism in which to study glaucoma, because of their high degree of availability, relatively low cost, short life-span, and amenability to experimental and genetic manipulation. In this review, we examine the numerous in vivo and in vitro rodent models of glaucoma, discuss the methods used to generate them, summarize some of the major findings obtained in these models, and identify individual strengths and weaknesses for the various systems.

Johnson, Thomas V.; Tomarev, Stanislav I.

2010-01-01

24

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

25

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

26

A model of Leptospirosis infection in an African rodent to determine risk to humans: Seasonal fluctuations and the impact of rodent control  

Microsoft Academic Search

Human leptospirosis (Leptospira spp. infection) is a worldwide public health problem that is of greatest concern for humid tropical and subtropical regions. The magnitude of the problem in these areas is larger because of the climatic and environmental conditions the bacterium face outside their hosts but also because of the frequency of contacts between people and sources of infection. Rodents

J. Holt; S. Davisb; H. Leirs

2006-01-01

27

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

28

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

29

Tropical Forests  

Microsoft Academic Search

\\u000a Tropical forests are one of the most prominent terrestrial biomes on earth, estimated to have originally covered 1.4 billion\\u000a ha (Reid 1992). Tropical forests generally occur in frost-free regions between the tropics of Cancer and Capricorn, in areas of relatively\\u000a high precipitation. Holdridge’s life zones system (Holdridge 1967), which is a commonly used vegetation classification protocol, distinguishes numerous kinds of

Rodolfo Dirzo

30

Rodent carcinogens: Setting priorities  

SciTech Connect

The human diet contains an enormous background of natural chemicals, such as plant pesticides and the products of cooking, that have not been a focus of carcinogenicity testing. A broadened perspective that includes these natural chemicals is necessary. A comparison of possible hazards for 80 daily exposures to rodent carcinogens from a variety of sources is presented, using an index (HERP) that relates human exposure to carcinogenic potency in rodents. A similar ordering would be expected with the use of standard risk assessment methodology for the same human exposure values. Results indicate that, when viewed against the large background of naturally occurring carcinogens in typical portions of common foods, the residues of synthetic pesticides or environmental pollutants rank low. A similar result is obtained in a separate comparison of 32 average daily exposures to natural pesticides and synthetic pesticides residues in the diet. Although the findings do not indicate that these natural dietary carcinogens are important in human cancer, they cast doubt on the relative importance for human cancer of low-dose exposures to synthetic chemicals.

Gold, L.S.; Slone, T.H.; Stern, B.R.; Manley, N.B.; Ames, B.N. (Lawrence Berkeley lab., CA (United States))

1992-10-09

31

Rodent carcinogens: setting priorities.  

PubMed

The human diet contains an enormous background of natural chemicals, such as plant pesticides and the products of cooking, that have not been a focus of carcinogenicity testing. A broadened perspective that includes these natural chemicals is necessary. A comparison of possible hazards for 80 daily exposures to rodent carcinogens from a variety of sources is presented, using an index (HERP) that relates human exposure to carcinogenic potency in rodents. A similar ordering would be expected with the use of standard risk assessment methodology for the same human exposure values. Results indicate that, when viewed against the large background of naturally occurring carcinogens in typical portions of common foods, the residues of synthetic pesticides or environmental pollutants rank low. A similar result is obtained in a separate comparison of 32 average daily exposures to natural pesticides and synthetic pesticide residues in the diet. Although the findings do not indicate that these natural dietary carcinogens are important in human cancer, they cast doubt on the relative importance for human cancer of low-dose exposures to synthetic chemicals. PMID:1411524

Gold, L S; Slone, T H; Stern, B R; Manley, N B; Ames, B N

1992-10-01

32

Introduction to Rodent Cardiac Imaging  

Microsoft Academic Search

Imaging is a noninvasive complement to traditional meth- ods (such as histology) in rodent cardiac studies. Assess- ments of structure and function are possible with ultrasound, microcomputed tomography (microCT), and magnetic reso- nance (MR) imaging. Cardiac imaging in the rodent poses a challenge because of the size of the animal and its rapid heart rate. Each aspect in the process

Kennita Johnson

2008-01-01

33

Tropical dermatology: viral tropical diseases  

Microsoft Academic Search

Viruses are important pathogens in tropical areas; most of them, especially the tropical hemorrhagic fevers, produce mucocutaneous manifestations. More than any other kind of pathogen, viruses have the possibility for being widespread, since they have a greater probability of mutation than do bacteria, can cross species barriers easily, and infect both human beings and animals in habitats with a great

Omar Lupi; Stephen K. Tyring

2003-01-01

34

Blood glucose concentration in caviomorph rodents  

Microsoft Academic Search

Hystricomorph rodents are a group of species that belong to the suborder Hystricognathi. They mainly inhabit South American (caviomorph) and African (phiomorph) habitats. This group of rodents has a divergent insulin structure. For example, insulin in this group of rodents exhibits only 1–10% of biological activity in comparison to other mammals. Therefore, hystricomorph rodents may hypothetically be unable to regulate

Juan C. Opazo; Mauricio Soto-Gamboa; Francisco Bozinovic

2004-01-01

35

Rodent Empathy and Affective Neuroscience  

PubMed Central

In the past few years, several experimental studies have suggested that empathy occurs in the social lives of rodents. This indicates that rodent behavioral models can be developed in an attempt to elucidate the mechanistic substrates of empathy at levels that have heretofore been unavailable. For example, the finding that mice from certain inbred strains express behavioral and physiological responses to conspecific distress, while others do not, underscores that the genetic underpinnings of empathy are specifiable and that in the future they could be harnessed to develop new therapies for human psychosocial impairments. However, the advent of rodent models of empathy is met at the outset with a number of theoretical and semantic problems that are similar to those previously confronted by studies of empathy in humans. The distinct underlying components of empathy must be differentiated from one another and from lay usage of the term. The primary goal of this paper is to review a set of seminal studies that are directly relevant to developing a concept of empathy in rodents. We first consider some of the psychological phenomena that have been associated with empathy, and within this context, we consider the component processes, or endophenotypes of rodent empathy. We then review a series of recent experimental studies that demonstrate the capability of rodents to detect and respond to the affective state of their social partners. We focus primarily on experiments that examine how rodents share affective experiences of fear, but we also highlight how similar types of experimental paradigms can be utilized to evaluate the possibility that rodents share positive affective experiences. Taken together, these studies were inspired by Jaak Panksepp’s theory that all mammals are capable of felt affective experiences.

Panksepp, Jules B.; Lahvis, Garet P.

2011-01-01

36

Tropical STIs  

Microsoft Academic Search

Chancroid, lymphogranloma venereum (LGV) and donovanosis (granuloma inguinale) are causes of genital ulceration found predominantly in tropical areas. Following recognition of the association between genital ulcers and HIV transmission, these conditions have been the subject of renewed interest. Although the incidence of all three conditions appears to be decreasing, a high index of suspicion should be maintained for new outbreaks

Nigel O’Farrell

2005-01-01

37

Decline and likely extinction of a northern Australian native rodent, the Brush-tailed Rabbit-rat Conilurus penicillatus  

Microsoft Academic Search

Contemporary fire patterns are considered the most likely cause for regional population decline amongst small to medium mammals in northern tropical Australia. Here we assess the extinction risk faced by a vulnerable north Australian native rodent, the Brush-tailed Rabbit-rat Conilurus penicillatus in relation to fire frequency. This species has recently suffered a significant contraction in range. We provide the first

Ronald S. C. Firth; Barry W. Brook; John C. Z. Woinarski; Damien A. Fordham

2010-01-01

38

Embargoed African Rodents and Monkeypox Virus  

MedlinePLUS

... 639-3311 Monkeypox Home > FACT SHEET Embargoed African Rodents and Monkeypox Virus On June 11, 2003, the ... joint order prohibiting the importation of all African rodents into the United States. The joint order also ...

39

Francisella tularensis in Rodents, China  

Microsoft Academic Search

A total of 420 rodents in China were examined for Francisella tularensis by polymerase chain reaction. The infection rates were 4.76% in total, and 11.65%, 10.00%, 6.56%, 1.77%, and 0% in Jilin, Xinjiang, Heilongjiang, Inner Mongolia, and Zhejiang, respectively. Sequence analysis showed that all the detected agents belonged to F. tularen- sis subsp. holarctica.

Fang Zhang; Wei Liu; May C. Chu; Jun He; Qing Duan; Xiao-Ming Wu; Pan-He Zhang; Qiu-Min Zhao; Hong Yang; Zhong-Tao Xin; Wu-Chun Cao

2006-01-01

40

Allometric disparity in rodent evolution.  

PubMed

In this study, allometric trajectories for 51 rodent species, comprising equal representatives from each of the major clades (Ctenohystrica, Muroidea, Sciuridae), are compared in a multivariate morphospace (=allometric space) to quantify magnitudes of disparity in cranial growth. Variability in allometric trajectory patterns was compared to measures of adult disparity in each clade, and dietary habit among the examined species, which together encapsulated an ecomorphological breadth. Results indicate that the evolution of allometric trajectories in rodents is characterized by different features in sciurids compared with muroids and Ctenohystrica. Sciuridae was found to have a reduced magnitude of inter-trajectory change and growth patterns with less variation in allometric coefficient values among members. In contrast, a greater magnitude of difference between trajectories and an increased variation in allometric coefficient values was evident for both Ctenohystrica and muroids. Ctenohystrica and muroids achieved considerably higher adult disparities than sciurids, suggesting that conservatism in allometric trajectory modification may constrain morphological diversity in rodents. The results provide support for a role of ecology (dietary habit) in the evolution of allometric trajectories in rodents. PMID:23610638

Wilson, Laura A B

2013-03-05

41

Allometric disparity in rodent evolution  

PubMed Central

In this study, allometric trajectories for 51 rodent species, comprising equal representatives from each of the major clades (Ctenohystrica, Muroidea, Sciuridae), are compared in a multivariate morphospace (=allometric space) to quantify magnitudes of disparity in cranial growth. Variability in allometric trajectory patterns was compared to measures of adult disparity in each clade, and dietary habit among the examined species, which together encapsulated an ecomorphological breadth. Results indicate that the evolution of allometric trajectories in rodents is characterized by different features in sciurids compared with muroids and Ctenohystrica. Sciuridae was found to have a reduced magnitude of inter-trajectory change and growth patterns with less variation in allometric coefficient values among members. In contrast, a greater magnitude of difference between trajectories and an increased variation in allometric coefficient values was evident for both Ctenohystrica and muroids. Ctenohystrica and muroids achieved considerably higher adult disparities than sciurids, suggesting that conservatism in allometric trajectory modification may constrain morphological diversity in rodents. The results provide support for a role of ecology (dietary habit) in the evolution of allometric trajectories in rodents.

Wilson, Laura A B

2013-01-01

42

21 CFR 1250.96 - Rodent control.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Rodent control. 1250.96 Section 1250.96...and Conditions on Vessels § 1250.96 Rodent control. Vessels shall be maintained free of rodent infestation through the use of traps,...

2010-04-01

43

21 CFR 1250.96 - Rodent control.  

Code of Federal Regulations, 2010 CFR

...2009-04-01 2009-04-01 false Rodent control. 1250.96 Section 1250.96...and Conditions on Vessels § 1250.96 Rodent control. Vessels shall be maintained free of rodent infestation through the use of traps,...

2009-04-01

44

The Tropical Meteorology Project  

NSDL National Science Digital Library

This site includes a link to Tropical Storm Forecast, yearly forecasts for tropical storms, named storms, typhoons, hurricanes, and intense hurricanes include the current forecast and archived forecasts. Other links lead to weather products, research, and articles from The Tropical Meteorology Project, Colorado State University Researchers, and the Tropical Storm Research community from around the world. There are also tropical storm frequently asked questions about typhoons, hurricanes, and other types of tropical storms.

Gray, William

2007-12-12

45

Female Mate Choice in Rodents  

Microsoft Academic Search

\\u000a The selection of suitable mates from a pool of potential candidates is one of the most important choices a female rodent has\\u000a to make. It influences Darwinian fitness directly via the number of offspring produced but also by its viability, fertility,\\u000a and fecundity. Numerous mechanisms have evolved to ensure this fitness increase by maximizing reproductive success. They act\\u000a at various

Jörns Fickel; Alexandra Weyrich

46

Prospects for biological control of rodent populations.  

PubMed

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. PMID:4587482

Wodzicki, K

1973-01-01

47

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

48

Prediction of rodent carcinogenicity for 30 chemicals.  

PubMed Central

Predictions of carcinogenic activity are made for 30 chemicals currently being assessed for rodent carcinogenicity by the U.S. National Toxicology Program. The predictions are based upon the chemical structure, the anticipated or reported mutagenicity, and the reported sub-chronic toxicity of each chemical. It is predicted that 13 chemicals will be noncarcinogenic to rodents, that 7 will be genotoxic carcinogens, and that 10 may show some evidence of presumed nongenotoxic rodent carcinogenesis.

Ashby, J

1996-01-01

49

Prediction of rodent carcinogenicity for 30 chemicals  

SciTech Connect

Predictions of carcinogenic activity are made for 30 chemicals currently being assessed for rodent carcinogenicity by the U.S. National Toxicology Program. The predictions are based upon the chemical structure, the anticipated or reported mutagenicity, and the reported sub-chronic toxicity of each chemical. It is predicted that 13 chemicals will be noncarcinogenic to rodents, that 7 will be genotoxic carcinogens, and that 10 may show some evidence of presumed nongenotoxic rodent carcinogenesis. 3 refs., 1 fig.

Ashby, J. [Zeneca Central Toxicology Lab., Cheshire (United Kingdom)

1996-10-01

50

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

51

Auditing laboratory rodent biosecurity programs.  

PubMed

A rodent biosecurity program that includes periodic evaluation of procedures used in an institution's vivarium can be used to ensure that best practices are in place to prevent a microbial pathogen outbreak. As a result of an ongoing comprehensive biosecurity review within their North American and European production facilities, the authors developed a novel biosecurity auditing process and worksheet that could be useful in other animal care and use operations. The authors encourage other institutions to consider initiating similar audits of their biosecurity programs to protect the health of their laboratory animals. PMID:24150170

Porter, William P; Horn, Mandy J; Cooper, Dale M; Klein, Hilton J

2013-10-22

52

Urban resident attitudes toward rodents, rodent control products, and environmental effects  

EPA Science Inventory

Rodent control in urban areas can result in the inadvertent mortality of non-target species (e.g., bobcats). However, there is little detailed information about rodent control practices of urban residents. Our objective was to evaluate urban rodent control behaviors in two area...

53

Rodent Control: Seal Up! Trap Up! Clean Up!  

MedlinePLUS

... can be found at http://www.usa.gov . Rodents Worldwide, rats and mice spread over 35 diseases. These diseases can be spread to humans directly, through handling of rodents, through contact with rodent feces, urine, or saliva, ...

54

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

55

Diet, caloric restriction, and the rodent bioassay  

Microsoft Academic Search

The diet can significantly alter the results of toxicity and carci- nogenicity studies. Ad libitum (AL) overfeeding of excessive calo- ries to sedentary adult rodents is one of the most poorly controlled variables affecting the current rodent bioassay. AL-overfed ro- dents develop an early onset of adverse metabolic events, endo- crine-disruptive degenerative diseases, and tumors that result in early morbidity

Kevin P. Keenan; Gordon C. Ballam; Keith A. Soper; Philippe Laroque; John B. Coleman; Rakesh Dixit

1999-01-01

56

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

57

Exposure to rodents and rodent-borne viruses among persons with elevated occupational risk.  

PubMed

Persons who have frequent contact with rodents as part of their occupation may be at increased risk of exposure to rodent-borne viruses such as Sin Nombre virus (SNV), the agent of hantavirus pulmonary syndrome, and Whitewater Arroyo virus (WWA), a New World arenavirus. Eighty-one persons with possible occupational exposure to rodents completed questionnaires and provided specimens for serologic testing. Seventy-two participants reported handling rodents as part of their job. The mean total number of rodents handled during participants' careers was approximately 2200. IgG antibody to lymphocytic choriomeningitis virus was detected in serum from one (1.2%) participant. IgG antibody to SNV, WWA, and Amapari viruses was not detected in any of the serum specimens. Despite considerable exposure to rodents, participants did not have significant serological evidence of exposure to rodent-borne viruses. PMID:12391776

Fritz, Curtis L; Fulhorst, Charles F; Enge, Barryett; Winthrop, Kevin L; Glaser, Carol A; Vugia, Duc J

2002-10-01

58

Mathematical models for hantavirus infection in rodents.  

PubMed

Hantavirus pulmonary syndrome is an emerging disease of humans that is carried by wild rodents. Humans are usually exposed to the virus through geographically isolated outbreaks. The driving forces behind these outbreaks is poorly understood. Certainly, one key driver of the emergence of these viruses is the virus population dynamics within the rodent population. Two new mathematical models for hantavirus infection in rodents are formulated and studied. The new models include the dynamics of susceptible, exposed, infective, and recovered male and female rodents. The first model is a system of ordinary differential equations while the second model is a system of stochastic differential equations. These new models capture some of the realistic dynamics of the male/female rodent hantavirus interaction: higher seroprevalence in males and variability in seroprevalence levels. PMID:16794943

Allen, Linda J S; McCormack, Robert K; Jonsson, Colleen B

2006-04-01

59

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

60

Nursing in the Tropics  

Microsoft Academic Search

Welcome to nursing in the tropics. The purpose of this chapter is to discuss some of the issues specifically associated with nursing in the tropics. You will have your own definition of nursing and there is no intention to define nursing here, though Henderson's definition is considered later in the paper. The term 'tropics' refers to a large part of

Teresa O'Connor

61

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

62

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

63

Rodent phylogeny revised: analysis of six nuclear genes from all major rodent clades  

PubMed Central

Background Rodentia is the most diverse order of placental mammals, with extant rodent species representing about half of all placental diversity. In spite of many morphological and molecular studies, the family-level relationships among rodents and the location of the rodent root are still debated. Although various datasets have already been analyzed to solve rodent phylogeny at the family level, these are difficult to combine because they involve different taxa and genes. Results We present here the largest protein-coding dataset used to study rodent relationships. It comprises six nuclear genes, 41 rodent species, and eight outgroups. Our phylogenetic reconstructions strongly support the division of Rodentia into three clades: (1) a "squirrel-related clade", (2) a "mouse-related clade", and (3) Ctenohystrica. Almost all evolutionary relationships within these clades are also highly supported. The primary remaining uncertainty is the position of the root. The application of various models and techniques aimed to remove non-phylogenetic signal was unable to solve the basal rodent trifurcation. Conclusion Sequencing and analyzing a large sequence dataset enabled us to resolve most of the evolutionary relationships among Rodentia. Our findings suggest that the uncertainty regarding the position of the rodent root reflects the rapid rodent radiation that occurred in the Paleocene rather than the presence of conflicting phylogenetic and non-phylogenetic signals in the dataset.

Blanga-Kanfi, Shani; Miranda, Hector; Penn, Osnat; Pupko, Tal; DeBry, Ronald W; Huchon, Dorothee

2009-01-01

64

Modeling panic disorder in rodents.  

PubMed

Panic disorder (PD) is a subtype of anxiety disorder in which the core phenomenon is the spontaneous occurrence of panic attacks. Although studies with laboratory animals have been instrumental for the understanding of its neurobiology and treatment, few review articles have focused on the validity of the currently used animal models for studying this psychopathology. Therefore, the aim of the present paper is to discuss the strengths and limits of these models in terms of face, construct and predictive validity. Based on the hypothesis that panic attacks are related to defensive responses elicited by proximal threat, most animal models measure the escape responses induced by specific stimuli. Some apply electrical or chemical stimulation to brain regions proposed to modulate fear and panic responses, such as the dorsal periaqueductal grey or the medial hypothalamus. Other models focus on the behavioural consequences caused by the exposure of rodents to ultrasound or natural predators. Finally, the elevated T-maze associates a one-way escape response from an open arm with panic attacks. Despite some limitations, animal models are essential for a better understanding of the neurobiology and pharmacology of PD and for discovering more effective treatments. PMID:23584609

Moreira, Fabrício A; Gobira, Pedro H; Viana, Thércia G; Vicente, Maria A; Zangrossi, Hélio; Graeff, Frederico G

2013-04-13

65

Fruit characters as a basis of fruit choice and seed dispersal in a tropical forest vertebrate community  

Microsoft Academic Search

Interactions between a large community of vertebrate frugivore-granivores (including 7 species of large canopy birds, 19 species of rodents, 7 species of ruminants, and 6 species of monkeys), and 122 fruit species they consume, were studied for a year in a tropical rainforest in Gabon.

A. Gautier-Hion; J.-M. Duplantier; R. Quris; F. Feer; C. Sourd; J.-P. Decoux; G. Dubost; L. Emmons; C. Erard; P. Hecketsweiler; A. Moungazi; C. Roussilhon; J.-M. Thiollay

1985-01-01

66

The MAM rodent model of schizophrenia.  

PubMed

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 hyperlocomotion, which can be utilized to verify the MAM phenotype. PMID:23559309

Lodge, Daniel J

2013-01-01

67

TROPICAL SPIDERWORT - AN INTRODUCTION  

Technology Transfer Automated Retrieval System (TEKTRAN)

Tropical spiderwort (also known as Benghal dayflower) has gone from relative obscurity as a roadside curiosity to troublesome weed with widespread economic impact in Georgia in less than 10 years. South Georgia and Florida are currently plagued by tropical spiderwort, but isolated populations have ...

68

Understanding arid environments using fossil rodent middens  

USGS Publications Warehouse

American rodent middens have made a more dramatic contribution to understanding past environments and the development of ecological theory than Australian rodent middens. This relates to differences in the natural environment, the landscape histories, the scale and scientific approaches of the researchers. The comparison demonstrates: the power of synoptic perspectives; the value of thorough macrofossil identification in midden analysis and its potential advance in Australia where pollen has dominated analyses, the value of herbaria and reference collections; the potential of environmental databases; the importance of scientific history and 'critical research mass' and; finally, the opportunistic nature of palaeoecological research. ?? 2002 Elsevier Science Ltd.

Pearson, S.; Betancourt, J. L.

2002-01-01

69

[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

70

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

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

2013-09-02

71

Population cycles in small rodents.  

PubMed

We conclude that population fluctuations in Microtus in southern Indiana are produced by a syndrome of changes in birth and death rates similar to that found in other species of voles and lemmings. The mechanisms which cause the changes in birth and death rates are demolished by fencing the population so that no dispersal can occur. Dispersal thus seems critical for population regulation in Microtus. Because most dispersal occurs during the increase phase of the population cycle and there is little dispersal during the decline phase, dispersal is not directly related to population density. Hence the quality of dispersing animals must be important, and we have found one case of increased dispersal tendency by one genotype. The failure of population regulation of Microtus in enclosed areas requires an explanation by any hypothesis attempting to explain population cycles in small rodents. It might be suggested that the fence changed the predation pressure on the enclosed populations. However, the fence was only 2 feet (0.6 meter) high and did not stop the entrance of foxes, weasels, shrews, or avian predators. A striking feature was that the habitat in the enclosures quickly recovered from complete devastation by the start of the spring growing season. Obviously the habitat and food quality were sufficient to support Microtus populations of abnormally high densities, and recovery of the habitat was sufficiently quick that the introduction of new animals to these enclosed areas resulted in another population explosion. Finally, hypotheses of population regulation by social stress must account for the finding that Microtus can exist at densities several times greater than normal without "stress" taking an obvious toll. We hypothesize that the prevention of dispersal changes the quality of the populations in the enclosures in comparison to those outside the fence. Voles forced to remain in an overcrowded fenced population do not suffer high mortality rates and continue to reproduce at abnormally high densities until starvation overtakes them. The initial behavioral interactions associated with crowding do not seem sufficient to cause voles to die in situ. What happens to animals during the population decline? Our studies have not answered this question. The animals did not appear to disperse, but it is possible that the method we used to measure dispersal (movement into a vacant habitat) missed a large segment of dispersing voles which did not remain in the vacant area but kept on moving. Perhaps the dispersal during the increase phase of the population cycle is a colonization type of dispersal, and the animals taking part in it are likely to stay in a new habitat, while during the population decline dispersal is a pathological response to high density, and the animals are not attracted to settling even in a vacant habitat. The alternative to this suggestion is that animals are dying in situ during the decline because of physiological or genetically determined behavioral stress. Thus the fencing of a population prevents the change in rates of survival and reproduction, from high rates in the increase phase to low rates in the decline phase, and the fenced populations resemble "mouse plagues." A possible explanation is that the differential dispersal of animals during the phase of increase causes the quality of the voles remaining at peak densities in wild populations to be different from the quality of voles at much higher densities in enclosures. Increased sensitivity to density in Microtus could cause the decline of wild populations at densities lower than those reached by fenced populations in which selection through dispersal has been prevented. Fencing might also alter the social interactions among Microtus in other ways that are not understood. The analysis of colonizing species by MacArthur and Wilson (27) can be applied to our studies of dispersal in populations of Microtus. Groups of organisms with good dispersal and colonizing ability are called r strategists because they have high reproductive po

Krebs, C J; Gaines, M S; Keller, B L; Myers, J H; Tamarin, R H

1973-01-01

72

Materiel Testing in the Tropics.  

National Technical Information Service (NTIS)

The US Army Tropic Test Center (USATTC) presents the 1975 update of Tropic Environmental Effects, retitled Materiel Testing in the Tropics. The handbook is a compendium of the US Army's experience in testing equipment in the humid tropics. Sources of info...

1975-01-01

73

Sequence shortening in the rodent ancestor.  

PubMed

Insertions and deletions (indels), together with nucleotide substitutions, are major drivers of sequence evolution. An excess of deletions over insertions in genomic sequences-the so-called deletional bias-has been reported in a wide range of species, including mammals. However, this bias has not been found in the coding sequences of some mammalian species, such as human and mouse. To determine the strength of the deletional bias in mammals, and the influence of mutation and selection, we have quantified indels in both neutrally evolving noncoding sequences and protein-coding sequences, in six mammalian branches: human, macaque, ancestral primate, mouse, rat, and ancestral rodent. The results obtained with an improved algorithm for the placement of insertions in multiple alignments, Prank(+F), indicate that contrary to previous results, the only mammalian branch with a strong deletional bias is the rodent ancestral branch. We estimate that such a bias has resulted in an ~2.5% sequence loss of mammalian syntenic region in the ancestor of the mouse and rat. Further, a comparison of coding and noncoding sequences shows that negative selection is acting more strongly against mutations generating amino acid insertions than against mutations resulting in amino acid deletions. The strength of selection against indels is found to be higher in the rodent branches than in the primate branches, consistent with the larger effective population sizes of the rodents. PMID:22128134

Laurie, Steve; Toll-Riera, Macarena; Radó-Trilla, Núria; Albà, M Mar

2011-11-29

74

Rodent Depredation-A Direct Seeding Problem.  

National Technical Information Service (NTIS)

Foresters have known for a long time that seed-eating rodents, birds, and insects must be circumvented before direct seeding can be successful. Advances have been made in reducing losses in the direct seeding of pine by the use of chemical repellents, and...

1965-01-01

75

Conjunctival lymphoid follicles in new world rodents.  

PubMed

We report for the first time, the detection of conjunctival lymphoid follicles (CLF) in the eyes of New World rodents. CLF were found in 7 of the 15 species examined, 6 of the 10 genera, and in at least one individual in four families of rodents. These follicles are dense collections of leukocytes in the conjunctival substantia propria with a thinned overlying epithelium lacking in goblet cells. Although the precise location of CLF within the conjunctiva varied from species to species, all CLF were found in the fornix of the conjunctival sac. In general, size and complexity of CLF varied with the size of the eye; the larger the eye, the larger and more complex the CLF. Our findings also reveal that some species of New World rodents, like the majority of Old World rodents examined in this and previous studies might lack CLF. However, until larger samples are examined, this is difficult to state with certainty. Consequently, the presence/absence of CLF at this point might not be informative for phylogenetic comparisons. Our findings also suggest the deer mouse, Peromyscus maniculatus, might serve as a useful model species for studying ocular infections and immunology of the eye. PMID:17722097

Astley, Roger A; Chodosh, James; Caire, William; Wilson, Gregory M

2007-09-01

76

Diet, caloric restriction, and the rodent bioassay.  

PubMed

The diet can significantly alter the results of toxicity and carcinogenicity studies. Ad libitum (AL) overfeeding of excessive calories to sedentary adult rodents is one of the most poorly controlled variables affecting the current rodent bioassay. AL-overfed rodents develop an early onset of adverse metabolic events, endocrine-disruptive degenerative diseases, and tumors that result in early morbidity and mortality. AL food consumption is extremely variable, but has a strong correlation with adult body weight, obesity, and survival. AL feeding of diets with modified protein, fiber, and energy content are not as effective as simple, moderate dietary (caloric) restriction (DR) in controlling these study variables. Moderate DR (70-75% of adult AL) is operationally simple and controls adult body weights, prevents obesity, and improves health and survival by reducing or delaying diet-related endocrine, renal, and cardiac diseases. Moderate DR provides a uniform rodent model, increases treatment exposure time, and increases the statistical sensitivity of these chronic bioassays to detect true treatment effects. Feeding a balanced diet by a moderate DR regimen of 70-75% of the maximum, unrestricted adult AL food intake is recommended for conducting well-controlled toxicity and carcinogenicity studies. PMID:10630587

Keenan, K P; Ballam, G C; Soper, K A; Laroque, P; Coleman, J B; Dixit, R

1999-12-01

77

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

78

Review: Genetic manipulation of the rodent placenta  

Microsoft Academic Search

The principal role of the placenta is the maintenance of pregnancy and promotion of fetal growth and viability. The use of transgenic rodents has greatly enhanced our understanding of placental development and function. However, embryonic lethality is often a confounding variable in determining whether a genetic modification adversely affected placental development. In these cases, it is beneficial to specifically manipulate

S. J. Renaud; M. A. Karim Rumi; M. J. Soares

2011-01-01

79

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

80

Hemagglutination by Pasteurellaceae isolated from rodents.  

PubMed

Pasteurellaceae notably P. pneumotropica, have been associated with severe outbreaks of respiratory disease in several species of rodents. Host-specific parasitism of Pasteurellaceae in rodents has hardly been studied. Since host tropism in many bacteria involves adhesive mechanisms, we examined the hemagglutinating (HA) properties of 44 isolates from different rodent species (mouse (15) rat (8), hamster (9), gerbil (10) and Mastomys (2)). Only 13 mouse isolates and the 2 Mastomys isolates hemagglutinated human (type O Rh+) and canine red blood cells (RBCs). No HA was found using RBCs from 10 other animal species. HA was not inhibited by simple sugars and glycoconjugates, but was completely inhibited by heating of bacterial cells for 10 min at 80 or 100 degrees C, partially inhibited by glutaraldehyde and inhibited in a dose-dependent mode by NaIO4, suggesting the involvement of bacterial polysaccharide structures in the HA process. Enrichment procedures did not reveal the presence of HA- subpopulations in HA+ isolates or the presence of HA+ subpopulations in HA- isolates. Electron microscopy revealed the presence of fimbriae both in HA+ and HA- isolates. A regularly structured (RS) layer was detected on cells of part of the HA+ isolates only. Our results suggest that Pasteurellaceae of mice and Mastomys may be related and differ from isolates isolated from other rodent species. PMID:8219497

Boot, R; Thuis, H; Teppema, J S

1993-06-01

81

Pinworm infections in laboratory rodents: a review  

Microsoft Academic Search

SUMMARY The important and common oxyurids which affect laboratory rodents- Syphacia spp., Aspiculuris tetraptera and Passafurus ambiguus-are discussed and reviewed. Their life histories, pathogenicity and immunity are examined, and mention is made of the influence of age, sex, strain and host status on in- fection. The importance of using worm-free animals in experimental work is stressed, and guidance is given

L. F. Taffs

1976-01-01

82

Neospora caninum detected in feral rodents  

Microsoft Academic Search

The role of rodents in the epidemiology of neosporosis was investigated by assaying brain tissue of feral mice (Mus musculus) and rats (Rattus norvegicus) for Neospora caninum. Both mouse and rat brain tissue were extracted for total DNA, and subjected to two different N. caninum-specific nested polymerase chain reaction (PCR) assays. A portion of brain tissue from the mice and

M. C. Jenkins; C. Parker; D. Hill; R. D. Pinckney; R. Dyer; J. P. Dubey

2007-01-01

83

Engineering rodents create key habitat for lizards  

Microsoft Academic Search

There is growing recognition among ecologists that ecosystem engineers play important roles in creating habitat for other species, but the comparative and combined effects of co-existing engineers are not well known. Here, we evaluated the separate and interactive effects of two burrowing rodents, Gunnison's prairie dogs (Cynomys gunnisoni) and banner-tailed kangaroo rats (Dipodomys spectabilis), on lizards in the Chihuahuan Desert

A. D. Davidson; D. C. Lightfoot; J. L. McIntyre

2008-01-01

84

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

85

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

86

7 CFR 58.147 - Insect and rodent control program.  

Code of Federal Regulations, 2010 CFR

... 2009-01-01 false Insect and rodent control program. 58.147 Section...Operating Procedures § 58.147 Insect and rodent control program. In addition to...performance of a regularly scheduled insect and rodent control program. Poisonous...

2009-01-01

87

7 CFR 58.147 - Insect and rodent control program.  

Code of Federal Regulations, 2010 CFR

... 2010-01-01 false Insect and rodent control program. 58.147 Section...Operating Procedures § 58.147 Insect and rodent control program. In addition to...performance of a regularly scheduled insect and rodent control program. Poisonous...

2010-01-01

88

7 CFR 58.247 - Insect and rodent control program.  

Code of Federal Regulations, 2010 CFR

... 2010-01-01 false Insect and rodent control program. 58.247 Section...Operating Procedures § 58.247 Insect and rodent control program. In addition to...performance of a regularly scheduled insect and rodent control program as outlined in...

2010-01-01

89

7 CFR 58.247 - Insect and rodent control program.  

Code of Federal Regulations, 2010 CFR

... 2009-01-01 false Insect and rodent control program. 58.247 Section...Operating Procedures § 58.247 Insect and rodent control program. In addition to...performance of a regularly scheduled insect and rodent control program as outlined in...

2009-01-01

90

Neglected Tropical Diseases outside the Tropics  

Microsoft Academic Search

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

Francesca F. Norman; Ana Pérez de Ayala; José-Antonio Pérez-Molina; Begoña Monge-Maillo; Pilar Zamarrón; Rogelio López-Vélez

2010-01-01

91

Meal-feeding rodents and toxicology research.  

PubMed

Most laboratory rodents used for toxicology studies are fed ad libitum, with unlimited access to food. As a result, ad libitum-fed rodents tend to overeat. Research demonstrates that ad libitum-fed rodents are physiologically and metabolically different from rodents fed controlled amounts of food at scheduled times (meal-fed). Ad libitum-fed rodents can develop hypertriglyceridemia, hypercholesterolemia, diet-induced obesity, nephropathy, cardiomyopathy, and pituitary, pancreatic, adrenal, and thyroid tumors, conditions likely to affect the results of toxicology research studies. In contrast, meal-feeding synchronizes biological rhythms and leads to a longer life span, lower body weight, lower body temperature, hypertrophy of the small intestine, and synchronization of hepatic and digestive enzymes. The circadian rhythms present in nearly all living organisms are entrained by light intensity and food intake, and peripheral clocks in all organs of the body, especially the GI tract and liver, are particularly sensitive to food intake. Feeding schedule has been demonstrated to alter the toxicity and metabolism of drugs including sodium valproate, chloral hydrate, acetaminophen, gentamicin, and methotrexate. Feeding schedule alters the expression of genes that code for Phase I, II, and III proteins, thereby altering the rate and amplitude of drug disposition. Rhythms of plasma insulin and glucagon that fluctuate with food ingestion are also altered by feeding schedule; ad libitum feeding promotes hyperinsulinemia which is a precursor for developing diabetes. The emerging field of chronopharmacology, the interaction of biological rhythms and drugs, will lead to optimizing the design and delivery of drugs in a manner that matches biological rhythms, but it is wise for toxicology researchers to consider feeding schedule when designing these experiments. It has been 10 years since the Society for Toxicologic Pathology voiced its position that feeding schedule is an important variable that should be controlled in toxicology experiments, and research continues to underscore this position. PMID:22642213

Carey, Gale B; Merrill, Lisa C

2012-06-13

92

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

93

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

94

Exploring the Tropical Rainforest.  

ERIC Educational Resources Information Center

|Presents a hands-on, exploratory science unit to study the biodiversity of the African tropical rain forest. Students study the vegetation, animal population, and human habitants of the forest. (MDH)|

McKee, Judith

1991-01-01

95

[Tropical climate pathology].  

PubMed

In addition to being a determinant factor for the development of infectious and parasitic diseases, tropical weather conditions can have harmful effects for the human organism different from those of temperate climates. Adverse effects can result from aggressive environmental factors such as ultraviolet radiation, extreme heat, abrupt changes in temperature, and tropical storms. In weather-sensitive subjects, exposure to tropical conditions increases the risk of acute reactions including ischemic heart disease, asthma attacks, and kidney stones. Adverse effects can be enhanced by suddenness of change in climate as underlined by the stress experienced by air travelers. In practice it is important to recognize that different tropical climates have different effects on health. Intertropical climates range from dry and rainy areas to plains and mountain areas. Knowledge of the concepts of climatopathology is necessary to advise patients on the choice of destination and the most favorable period for travel. PMID:9612744

Besancenot, J P

1997-01-01

96

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

2006-10-24

97

Field and experimental studies of poxvirus infections in rodents  

PubMed Central

Data are presented from serological and virological investigations of natural and experimental infections, in rodents, with different poxviruses. The demonstration of poxvirus antibodies (virus neutralizing antibodies, antihaemagglutinins, and precipitins) in the kidneys and/or lungs of rodents from Europe and Africa, and the isolation of poxviruses from them, all indicate that rodents may be poxvirus carriers. Isolates from rodents differed in their properties. Some, from Turkmenistan rodents or from white rats caught near Moscow, appeared to be very close to cowpox virus, while others (from Zaire rodents) were identical to variola-like (whitepox) viruses found earlier in monkeys in the same region. The results suggest that rodents that carry the virus closely similar to cowpox virus might be a source of infection for other animal species.

Marennikova, S. S.

1979-01-01

98

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

99

Neglected Tropical Diseases outside the Tropics  

Microsoft Academic Search

BackgroundThe 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.MethodsRetrospective study of a cohort of immigrants and travelers diagnosed with one of the 13 core NTDs at

Francesca F. Norman; Ana Pérez de Ayala; José-Antonio Pérez-Molina; Begoña Monge-Maillo; Pilar Zamarrón; Rogelio López-Vélez

2010-01-01

100

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

101

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

102

REVIEW: GENETIC MANIPULATION OF THE RODENT PLACENTA  

PubMed Central

The principal role of the placenta is the maintenance of pregnancy and promotion of fetal growth and viability. The use of transgenic rodents has greatly enhanced our understanding of placental development and function. However, embryonic lethality is often a confounding variable in determining whether a genetic modification adversely affected placental development. In these cases, it is beneficial to specifically manipulate the placental genome. The purpose of this review is to summarize available methodologies for specific genetic modification of the rodent placenta. By restricting genetic alterations to the trophoblast lineage, it is possible to gain a deeper understanding of placental development that perhaps will lead to gene-targeted therapies to rescue irregular placentation in transgenic animals or in women at high-risk for placenta-associated pregnancy complications.

Renaud, Stephen J.; Rumi, M.A. Karim; Soares, Michael J.

2011-01-01

103

Review: Genetic manipulation of the rodent placenta.  

PubMed

The principal role of the placenta is the maintenance of pregnancy and promotion of fetal growth and viability. The use of transgenic rodents has greatly enhanced our understanding of placental development and function. However, embryonic lethality is often a confounding variable in determining whether a genetic modification adversely affected placental development. In these cases, it is beneficial to specifically manipulate the placental genome. The purpose of this review is to summarize available methodologies for specific genetic modification of the rodent placenta. By restricting genetic alterations to the trophoblast lineage, it is possible to gain a deeper understanding of placental development that perhaps will lead to gene-targeted therapies to rescue irregular placentation in transgenic animals or in women at high-risk for placenta-associated pregnancy complications. PMID:21256588

Renaud, S J; Karim Rumi, M A; Soares, M J

2011-01-22

104

Pinworm infections in laboratory rodents: a review.  

PubMed

The important and common oxyurids which affect laboratory rodents- Syphacia spp., Aspiculuris tetraptera and Passalurus ambiguus-are discussed and reviewed. Their life histories, pathogenicity and immunity are examined, and mention is made of the influence of age, sex, strain and host status on infection. The importance of using worm-free animals in experimental work is stressed, and guidance is given on diagnosis and control. PMID:768631

Taffs, L F

1976-01-01

105

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

106

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

107

Tropical Travel and Skin Infections  

MedlinePLUS

... Vitamin D Cosmetic treatments Gold Triangle Awards Home Media resources Stats and facts Prevention and care Tropical travel Tropical travel More than 1 million Americans travel to developing nations each year. Travelers are ...

108

Epizootiology of Tropical Canine Pancytopenia.  

National Technical Information Service (NTIS)

Tropical canine pancytopenia (TCP) is a newly recognized infectious disease of dogs in diverse tropical and subtropical areas. The disease is characterized by hemorrhage, pancytopenia, severe emaciation and persistent infection. Dogs with TCP are often pr...

D. L. Huxsoll H. L. Amyx J. A. Ferguson P. K. Hildebrandt R. M. Nims

1970-01-01

109

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

110

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

111

[Cardiomyopathies in tropical areas].  

PubMed

Some particular features of the cardiomyopathies (CM) observed in the tropics, especially in Africa, are emphasized in this study. Chronic parietal endocarditis is excluded from the CM group. The author presents facts that justify the linking of that affection to endocardial diseases. Myocardiopathies are acute ailments presenting with congestive lesions, reversible under etiological therapy. Anemic and beri-beri myocardiopathies are not unusual in the tropics and present a hyperkinetic syndrome before the stage of advanced cardiac insufficiency. Infectious or parasitic myocarditis seem frequent in the tropics. The author recalls the characteristics of the myocarditis in the human african trypanosomiasis which he opposes, particularly, to the american trypanosomiasis. The reality of bilharzial myocarditis is more debatable while bilharzial pulmonary hypertension is well documented. Chronic congestive CM presents a few specific characteristics in the tropics. The features, well described in temperate regions, are found in the tropics with a particularly unfortunate prognosis. Some alcoholic myocardiopathies have been observed. The rare occurrence of hypertrophic CM in the tropics results, seemingly, from a lack of exploratory means. The author studies briefly a recent series of 31 cases in Abidjan. Post-partum myocardiopathy seems to be the clinical appearance of a latent myocardial insufficiency of the normal post-partum in women presenting with associated risks factors (anemia, malnutrition, overwork, excessive sodium intake, etc.). An early diagnosis enables a cure only by resting, but it is sometimes necessary to associate a medical treatment. Death by embolism or the passing to chronicity are however possible. Drepanocytic CM is debatable and in many cases, seems hardly differentiated from anemic myocardiopathy.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:3777821

Bertrand, E

1986-06-01

112

Tropical Cyclones (1980) - Central Pacific.  

National Technical Information Service (NTIS)

Tropical Storm Carmen and Hurricane Kay are described and their tracks are charted. Tropical Storm Carmen began as an active cluster of convective activity centered near 04N 178W on April 3, 1980. It became a Tropical Depression as it showed a drift towar...

A. K. T. Chun

1981-01-01

113

Microbial Safety of Tropical Fruits  

Microsoft Academic Search

There are approximately 140 million tons of over 3,000 types of tropical fruits produced annually worldwide. Tropical fruits, once unfamiliar and rare to the temperate market, are now gaining widespread acceptance. Tropical fruits are found in a variety of forms, including whole, fresh cut, dried, juice blends, frozen, pulp, and nectars in markets around the world. Documented outbreaks of foodborne

Laura K. Strawn; Keith R. Schneider; Michelle D. Danyluk

2011-01-01

114

Tracking genome organization in rodents by Zoo-FISH  

Microsoft Academic Search

The number of rodent species examined by modern comparative genomic approaches, particularly chromosome painting, is limited.\\u000a The use of human whole-chromosome painting probes to detect regions of homology in the karyotypes of the rodent index species,\\u000a the mouse and rat, has been hindered by the highly rearranged nature of their genomes. In contrast, recent studies have demonstrated\\u000a that non-murid rodents

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

2008-01-01

115

Distinct host cell fates for human malignant melanoma targeted by oncolytic rodent parvoviruses.  

PubMed

The rodent parvoviruses are known to be oncoselective, and lytically infect many transformed human cells. Because current therapeutic regimens for metastatic melanoma have low response rates and have little effect on improving survival, this disease is a prime candidate for novel approaches to therapy, including oncolytic parvoviruses. Screening of low-passage, patient-derived melanoma cell lines for multiplicity-dependent killing by a panel of five rodent parvoviruses identified LuIII as the most melanoma-lytic. This property was mapped to the LuIII capsid gene, and an efficiently melanoma tropic chimeric virus shown to undergo three types of interaction with primary human melanoma cells: (1) complete lysis of cultures infected at very low multiplicities; (2) acute killing resulting from viral protein synthesis and DNA replication, without concomitant expansion of the infection, due to failure to export progeny virions efficiently; or (3) complete resistance that operates at an intracellular step following virion uptake, but preceding viral transcription. PMID:24074565

Vollmers, Ellen M; Tattersall, Peter

2013-08-09

116

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

117

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

118

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 -.

119

Microbial Genomics: Tropical Treasure?  

Microsoft Academic Search

A Brazilian consortium has unveiled the genomic DNA sequence of the purple-pigmented bacterium Chromobacterium violaceum, a dominant component of the tropical soil microbiota. The sequence provides insight into the abundant potential of this organism for biotechnological and pharmaceutical applications.

Craig Stephens

2004-01-01

120

Tropical Whitefly IPM Project  

Microsoft Academic Search

The Tropical Whitefly IPM Project (TWFP) is an initiative of the Systemwide IPM Programme of the Consultative Group on International Agricultural Research (CGIAR), financed by the Department for International Development (DFID) of the United Kingdom, the Danish International Development Agency (DANIDA), the United States Department of Agriculture (USDA) and Agency for International Development (USAID), the Australian Centre for International Agricultural

Francisco J. Morales

2006-01-01

121

Estrogen and Hippocampal Plasticity in Rodent Models  

PubMed Central

Accumulating evidence indicates that ovarian hormones regulate a wide variety of non-reproductive functions in the central nervous system by interacting with several molecular and cellular processes. A growing animal literature using both adult and aged rodent models indicates that 17?-estradiol, the most potent of the biologically relevant estrogens, facilitates some forms of learning and memory, in particular those that involve hippocampal-dependent tasks. A recently developed triple-transgenic mouse (3xTg-AD) has been widely used as an animal model of Alzheimer's disease, as this mouse exhibits an age-related and progressive neuropathological phenotype that includes both plaque and tangle pathology mainly restricted to hippocampus, amygdala and cerebral cortex. In this report, we examine recent studies that compare the effects of ovarian hormones on synaptic transmission and synaptic plasticity in adult and aged rodents. A better understanding of the non-reproductive functions of ovarian hormones has far-reaching implications for hormone therapy to maintain health and function within the nervous system throughout aging.

Foy, Michael R.; Baudry, Michel; Brinton, Roberta Diaz; Thompson, Richard F.

2010-01-01

122

Changes in tau phosphorylation in hibernating rodents.  

PubMed

Tau is a cytoskeletal protein present mainly in the neurons of vertebrates. By comparing the sequence of tau molecule among different vertebrates, it was found that the variability of the N-terminal sequence in tau protein is higher than that of the C-terminal region. The N-terminal region is involved mainly in the binding of tau to cellular membranes, whereas the C-terminal region of the tau molecule contains the microtubule-binding sites. We have compared the sequence of Syrian hamster tau with the sequences of other hibernating and nonhibernating rodents and investigated how differences in the N-terminal region of tau could affect the phosphorylation level and tau binding to cell membranes. We also describe a change, in tau phosphorylation, on a casein kinase 1 (ck1)-dependent site that is found only in hibernating rodents. This ck1 site seems to play an important role in the regulation of tau binding to membranes. PMID:23606524

León-Espinosa, Gonzalo; García, Esther; García-Escudero, Vega; Hernández, Félix; Defelipe, Javier; Avila, Jesús

2013-04-19

123

The impacts of invasive rodents on island invertebrates  

Microsoft Academic Search

The widespread invasive rodents Rattus norvegicus, R. rattus, R. exulans and Mus musculus have been implicated in the decline and extinction of hundreds of island endemic vertebrates, but their effects on island invertebrates are less well-known. Here I present the first global review of the subject, which confirms that large-bodied invertebrates are most at risk from these rodents, and that

James J. H. St Clair

2011-01-01

124

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

125

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

126

Visual Landmarks Facilitate Rodent Spatial Navigation in Virtual Reality Environments  

ERIC Educational Resources Information Center

|Because many different sensory modalities contribute to spatial learning in rodents, it has been difficult to determine whether spatial navigation can be guided solely by visual cues. Rodents moving within physical environments with visual cues engage a variety of nonvisual sensory systems that cannot be easily inhibited without lesioning brain…

Youngstrom, Isaac A.; Strowbridge, Ben W.

2012-01-01

127

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...

128

Functional Evolution of the Feeding System in Rodents  

Microsoft Academic Search

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

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

2012-01-01

129

The care and management of laboratory hystricomorph rodents  

Microsoft Academic Search

SUMMARY The caging, feeding and handling of four unusual laboratory hystricomorph rodents is described. These rodents are: the chinchilla (Chinchilla laniger), the agouti (Dasyprocta aguti), the acouchi (Myoprocta pratti), and the African porcupine (Hystrix cristata). The animals were kept for study of their reproduction and some details of this are given. The Hystricomorpha is a sub-order of the Order Rodentia

Barbara J. Weir

1967-01-01

130

Recent and Widespread Rapid Morphological Change in Rodents  

Microsoft Academic Search

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

Oliver R. W. Pergams; Joshua J. Lawler; Erik I. Svensson

2009-01-01

131

Genetic variants of Orientia tsutsugamushi in domestic rodents, northern China.  

PubMed

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. PMID:23764295

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

2013-07-01

132

Licking and liking: The assessment of hedonic responses in rodents  

Microsoft Academic Search

Affective processes are a key determinant of behaviour: At its simplest, liked stimuli are approached while disliked stimuli are avoided. Although assessing hedonic responses in nonverbal animals can be difficult, one relatively tractable approach relies on detailed analyses of rodents' consummatory behaviour. Rodents typically produce rhythmic sets of licks that can be grouped into clusters on the basis of the

Dominic M. Dwyer

2012-01-01

133

Licking and liking: The assessment of hedonic responses in rodents  

Microsoft Academic Search

Affective processes are a key determinant of behaviour: at its simplest, liked stimuli are approached while disliked stimuli are avoided. Although assessing hedonic responses in non-verbal animals can be difficult, one relatively tractable approach relies on detailed analyses of rodents’ consummatory behaviour. Rodents typically produce rhythmic sets of licks that can be grouped into clusters on the basis of the

Dominic M. Dwyer

2011-01-01

134

[Edema and the tropics].  

PubMed

People visiting or living in tropical or subtropical regions are exposed to various factors, which can lead to edema. Tourists staying for only a short time in the tropics are exposed to different risks, with other disease patterns, than people living in the tropics or immigrants from tropical regions. The differential diagnosis of edema and swelling is extensive and it can sometimes be difficult to distinguish classical edema with fluid retention in the extravascular interstitial space, from lymphedema or swelling due to other aetiologies. The patients often connect the edema to their stay in the tropics although it may have been pre-existing with no obvious relation to their travels. Already the long trip in the plane can lead to an "economy class syndrome" due to deep venous thrombosis. Contacts with animal or plant toxins, parasites or parasitic larvae can produce peripheral edema. The diagnosis can often only be made by taking a meticulous history, checking for eosinophilia and with the help of serological investigations. Chronic lymphedema or elephantiasis of the limbs is often due to blocked lymph vessels by filarial worms. It has to be distinguished from other forms as e.g. podoconiosis due to blockage by mineral particles in barefoot walking people. The trend to book adventure and trekking holidays at high altitude leads to high altitude peripheral edema or non-freezing cold injuries such as frostbites and trench foot. Edema can be an unwanted side effect of a range of drugs e.g. nifedipine, which is used to prevent and treat high altitude pulmonary edema. Protein malnutrition, (Kwashiorkor), and vitamin B6 deficiency, (Beri-Beri) are very rarely observed in immigrants and almost never in tourists. A very painful swelling of fingers and hands in children and young adults of African origin can be observed during a sickle cell crisis. Many protein loosing nephropathies connected with plant and animal toxins but also bacterial, viral or parasitic agents, can lead to edema. But very often edema in tourists or immigrants from the tropics is not related to their stay abroad. To take an accurate history of the itinerary, eating habits and exposure to water etc. is very important. Knowledge of the precise epidemiology and geographic distribution of diseases are essential. PMID:15605460

Holzer, B R

2004-11-01

135

Scatter-hoarding rodents prefer slightly astringent food.  

PubMed

The mutualistic interaction between scatter-hoarding rodents and their seed plants is highly complex yet poorly understood. Plants may benefit from the seed dispersal behavior of rodents, as long as seed consumption is minimized. In parallel, rodents may maximize foraging efficiency and cache high-quality resources for future consumption. Defensive compounds, such as tannins, are thought to be a major mechanism for plant control over rodent behavior. However, previous studies, using naturally occurring seeds, have not provided conclusive evidence supporting this hypothesis. Here, we test the importance of tannin concentrations on the scatter-hoarding behavior of rodents by using an artificial seed system. We combined feeding trials and field observations to examine the overall impact of seed tannin concentrations on rodent behavior and health. We found that rodents favored seeds with an intermediate amount of tannin (~5%) in the field. Meanwhile, in rodents that were fed a diet with different tannin content, only diets with high tannin content (25%, 15%, and 10%) caused a significant negative influence on rodent survival and health. Significant differences were not found among treatments with tannin levels of 0-5%. In contrast to many existing studies, our results clearly demonstrate that scatter-hoarding rodents prefer slightly 'astringent' food. In the co-evolutionary arms race between plants and animals, our results suggest that while tannins may play a significant role in reducing general predation levels by the faunal community, they have no precise control over the behavior of their mutualistic partner. Instead, the two partners appear to have reached an evolutionary point where both parties receive adequate benefits, with the year-to-year outcome being dependent on a wide range of factors beyond the control of either partner. PMID:22046284

Wang, Bo; Chen, Jin

2011-10-26

136

Brain acetylcholinesterase activity recovery following acute methyl parathion intoxication in two feral rodent species: comparison to laboratory rodents  

SciTech Connect

Widespread use of organophosphorus insecticides (OPs) has produced both acute and chronic intoxication among nontarget organisms. Most such studies have included fish and birds as opposed to mammals. However, numerous OP toxicity studies have been conducted on laboratory rodents creating a temptation to apply this data to feral rodents. Chronic OP exposure has been reported to produce cholinergic adaptation which in turn lowers mortality rates following a subsequent acute anticholinesterase exposure. The relevance that these laboratory rodent studies have on feral rodents is subject to debate. Field studies involving OP exposure among nontarget feral mammals have produced contradictory results. Increased mortality as a result of repeated OP application has been reported. This observation may be of considerable importance to nontarget feral rodent populations due to the repetitive nature of OP application protocols. The ability of feral rodents to recover brain AChE activity (BAA) between OP application intervals undoubtedly promotes their survival. This study investigated and compared BAA recovery following acute oral methyl parathion intoxication among 2 feral rodent species and among 2 common laboratory rodent species.

Roberts, D.K.; Silvey, N.J.; Bailey, E.M. Jr.

1988-07-01

137

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

138

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.

139

Tuberculosis in tropical Africa  

PubMed Central

Up to the end of the nineteenth century the tubercle bacillus apparently had little opportunity of disseminating among the rather isolated tribes of tropical Africa. With the creation of large centres of trade and industry in the wake of European colonization, tuberculosis seems to have spread rapidly over the continent and is today found everywhere. In a number of tuberculosis prevalence surveys conducted by WHO during 1955-60, randomly selected population groups were tuberculin tested, X-rayed and had sputa examined by direct microscopy. The three methods of examination were applied independently of one another. Data collected during the surveys have been analysed with a view to discovering common epidemiological features of tuberculosis in tropical Africa, assessing the reliability of the diagnostic methods employed and discussing their usefulness in future tuberculosis control programmes.

Roelsgaard, E.; Iversen, E.; Bl?cher, C.

1964-01-01

140

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 runs from July 26 at 1315 UTC (9:15 a.m. EDT) to July 28 at 1045 UTC (6:45 a.m. EDT). (No audio) Credit: NASA/NOAA GOES Project

Robert Garner

2011-07-28

141

Exploring Tropical Cyclones  

NSDL National Science Digital Library

This website offers an overview and sample of the Exploring Tropical Cyclones module (the actual module must be purchased). The module introduces students to the dynamic forces generating cyclones by using geographic information system (GIS) software to analyze data sets. Students explore the global distribution of cyclones, then focus in on U.S. hurricane hazards. They complete the module with an investigation of hurricanes in New York City.

142

Energetics of tropical hibernation  

Microsoft Academic Search

In this field study, the energetic properties of tropical hibernation were investigated by measuring oxygen consumption and\\u000a body temperature of the Malagasy primate Cheirogaleus medius in their natural hibernacula. These lemurs use tree holes with extremely varying insulation capacities as hibernacula. In\\u000a poorly insulated tree holes, tree hole temperature and body temperature fluctuated strongly each day (between 12.8 and 34.4°C).

K. H. Dausmann; J. Glos; G. Heldmaier

2009-01-01

143

Tropical Anvil Cirrus Microphysics  

NASA Astrophysics Data System (ADS)

This study synthesizes data collected during a number of field campaigns by in-situ aircraft to characterize the microphysical properties of tropical, convectively-generated cirrus. The field campaigns include the Tropical Rain Measuring Mission KWAJEX campaign near Kwajalein, M. I., KAMP (the Keys Area Microphysics Project) and the Cirrus Regional Study of Tropical Anvils and Cirrus Layers (CRYSTAL) Florida Area Cirrus Experiment (FACE), both over southern Florida, and CAMEX-4 (the fourth convection and moisture experiment), studying hurricanes off the east coast of Florida. The measurements include particle size distribution and particle shape information, direct measurements of the condensed water content (CRYSTAL-FACE), and radar imagery. We examine the temperature dependence and vertical variability of the ice water content (IWC), extinction, and effective radii, and deduce the ensemble-mean ice particle densities. Data obtained in quiescent regions outside of convection are compared to observations within convective cells. The relationship between the properties of the particle size distributions and proximity to convection are examined. The IWCs show a strong temperature dependence and dependence on distance below cloud top. The IWCs are larger in the convective regions than in the quiescent regions, and the particle size distributions are markedly broader. Ensemble-mean ice particle densities are a strong function of the breadth of the particle size distributions.

Heymsfield, A.; Bansemer, A.; Schmitt, C.; Baumgardner, D.; Poellot, M.; Twohy, C.; Weinstock, E. M.; Smith, J. T.; Sayres, D.; Avallone, L.; Hallar, G.

2003-12-01

144

Automatic cortical thickness analysis on rodent brain  

NASA Astrophysics Data System (ADS)

Localized difference in the cortex is one of the most useful morphometric traits in human and animal brain studies. There are many tools and methods already developed to automatically measure and analyze cortical thickness for the human brain. However, these tools cannot be directly applied to rodent brains due to the different scales; even adult rodent brains are 50 to 100 times smaller than humans. This paper describes an algorithm for automatically measuring the cortical thickness of mouse and rat brains. The algorithm consists of three steps: segmentation, thickness measurement, and statistical analysis among experimental groups. The segmentation step provides the neocortex separation from other brain structures and thus is a preprocessing step for the thickness measurement. In the thickness measurement step, the thickness is computed by solving a Laplacian PDE and a transport equation. The Laplacian PDE first creates streamlines as an analogy of cortical columns; the transport equation computes the length of the streamlines. The result is stored as a thickness map over the neocortex surface. For the statistical analysis, it is important to sample thickness at corresponding points. This is achieved by the particle correspondence algorithm which minimizes entropy between dynamically moving sample points called particles. Since the computational cost of the correspondence algorithm may limit the number of corresponding points, we use thin-plate spline based interpolation to increase the number of corresponding sample points. As a driving application, we measured the thickness difference to assess the effects of adolescent intermittent ethanol exposure that persist into adulthood and performed t-test between the control and exposed rat groups. We found significantly differing regions in both hemispheres.

Lee, Joohwi; Ehlers, Cindy; Crews, Fulton; Niethammer, Marc; Budin, Francois; Paniagua, Beatriz; Sulik, Kathy; Johns, Josephine; Styner, Martin; Oguz, Ipek

2011-03-01

145

Brain/body relations among myomorph rodents.  

PubMed

The observed increase in brain size (E) with body size (P) 'from mouse to elephant' may be described by a power relation E = kPb, where b is near 2/3 or 3/4. That this reflects a single, strong interaction between brain and body evolution is challenged by two observations: (1) different species with the same body size may have markedly different brain sizes, and (2) the value of b at the species level is usually nearer 1/3 than 2/3. Furthermore, the idea that a bigger brain means greater versatility on the part of its owner makes a strong statement about such animals. We examined these notions by measuring cranial volumes of 1,480 skulls from 62 subspecies of cricetid and murid rodents. Values of k and b were obtained by computing a reduced major axis on E and P across all specimens (b = 0.693), and when specimens were partitioned by genus (b = 0.456) and subspecies level (b = 0.338). Thus, the overall slope of 7/10 is not a simple extension of the developmental rules at the subspecies level (b near 1/3) nor even at the genus level (b near 4/9). Rather, it may reflect the most likely path for an interbreeding population subjected to varying selective pressures on one or more correlated traits. Furthermore, among the rodents studied, folivorous subspecies averaged about 2/3 as much brain as granivorous, insectivorous or generalist subspecies of the same body weight. Also, Old World rats, which may be more versatile than wood rats, gained their competitive advantage despite having relatively smaller brains. PMID:3280099

Mann, M D; Glickman, S E; Towe, A L

1988-01-01

146

Fire in tropical pine ecosystems  

Microsoft Academic Search

\\u000a The genus Pinus extends into tropical environments in the neotropics of Mesoamerica, the Caribbean islands, and the southern tip of the Florida\\u000a peninsula. In Old World tropics, pines occur from southeast China to the Philippines and Southeast Asia. Only one species,\\u000a Pinus merkusii De Vries in Sumatra, occurs south of the equator. Pines in the tropics, as elsewhere, are associated

Ronald L. Myers; Dante Arturo Rodríguez-Trejo

147

Tropical disturbances in a GCM  

Microsoft Academic Search

We have analyzed the tropical disturbances in a 11-layer atmospheric general circulation model (GCM) on a 2.5° × 3.75° horizontal grid coupled to a 50 m-mixed layer ocean. Due to the coarse resolution, the GCM is unable to resolve adequately tropical cyclones. The tropical disturbances simulated by the GCM are much weaker and have a much larger horizontal extent. However,

R J Haarsma; J F B Mitchell; C A Senior

1993-01-01

148

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

149

Observational Analysis of Tropical Cyclone Formation.  

National Technical Information Service (NTIS)

This study investigates the genesis of tropical cyclones through a combination of the compositing approach and the case study approach. Twelve composite data sets are analyzed from the tropical Northwest Pacific and tropical Northwest Atlantic Oceans. Eac...

J. L. McBride W. M. Gray

1979-01-01

150

Eastern North Pacific Tropical Cyclones, 1972.  

National Technical Information Service (NTIS)

The 1972 tropical cyclone season began in the eastern North Pacific Ocean on May 31 and continued through November 15. Twelve named tropical cyclones developed of which four reached tropical storm intensity and eight reached hurricane strength. A comparis...

1973-01-01

151

Lack of seroreactivity to Ehrlichia chaffeensis among rodent populations.  

PubMed

A retrospective serosurvey for antibodies to Ehrlichia chaffeensis was conducted on eight species of wild rodents (Mus musculus, Oryzomys palustris, Peromyscus leucopus, Rattus norvegicus, Reithrodontomys humulis, Sciurus carolinensis, Sciurus niger, and Sigmodon hispidus) from the southeastern United States. Serum samples (n = 281) collected between 1973 and 1993 were evaluated using an indirect fluorescent antibody test. All samples, screened at a dilution of 1:32, were negative for antibodies to E. chaffeensis. Sixty-three percent of the rodents tested were from areas where E. chaffeensis has been confirmed or is strongly suspected to be endemic. These data suggest limited or no involvement of rodents in the epidemiology of E. chaffeensis. PMID:9577793

Lockhart, J M; Davidson, W R; Stallknecht, D E; Dawson, J E

1998-04-01

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

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

154

Tropical Whitefly IPM Project.  

PubMed

The Tropical Whitefly IPM Project (TWFP) is an initiative of the Systemwide IPM Programme of the Consultative Group on International Agricultural Research (CGIAR), financed by the Department for International Development (DFID) of the United Kingdom, the Danish International Development Agency (DANIDA), the United States Department of Agriculture (USDA) and Agency for International Development (USAID), the Australian Centre for International Agricultural Research (ACIAR), and the New Zealand Agency for International Development (NZAID), to manage whitefly pests and whitefly-transmitted viruses in the Tropics. Participating CGIAR and other international centers include the Centre for International Tropical Agriculture (CIAT); the International Institute of Tropical Agriculture (IITA); The International Potato Centre (CIP); the Asian Vegetable Research and Development Centre (AVRDC); and the International Centre of Insect Physiology and Ecology (ICIPE), in close collaboration with the National Resources Institute (NRI-UK); national agricultural research institutions; agricultural universities; and advanced agricultural research laboratories in Africa, Asia, Europe, the Pacific Region, and the Americas. The TWFP was launched in 1996 as five separate but closely linked subprojects targeting: (1) Bemisia tabaci as a vector of viruses affecting cassava and sweet potato in sub-Saharan Africa (IITA, NRI, CIP, CIAT); (2) B. tabaci as a vector of viruses in mixed cropping systems of Mexico, Central America, and the Caribbean (CIAT); (3) B. tabaci as a vector of viruses in mixed cropping systems of eastern and southern Africa (ICIPE, AVRDC); (4) B. tabaci as a vector of viruses in mixed cropping systems of Southeast Asia (AVRDC); (5) Trialeurodes vaporariorum as a pest in mixed cropping systems of the Andean highlands (CIAT); and (6) whiteflies as pests of cassava in South America (CIAT). Diagnostic surveys conducted in Phase I (1997-2000) clearly showed that the two main whitefly pests in the Tropics are B. tabaci and, in the highlands, T. vaporariorum. Other whitefly species investigated by the TWFP included B. afer and Aleurotrachelus socialis. B. tabaci is the main vector of plant viruses inducing African cassava mosaic disease, sweet potato virus disease, bean golden mosaic disease, and many other diseases of horticultural crops, mainly tomato, hot and sweet peppers, squash, melon, and several other cucurbits. Genetic resistance was identified as the most important component of an IPM programme, followed by phytosanitary, cultural and legal measures. The two most important factors contributing to whitefly/virus epidemics were shown to be pesticide abuse and the use of virus-infected planting materials. Biological control is only effective in cropping systems with minimal or rational use of insecticides, and should be considered only as a complementary IPM strategy. Farmer education and technical assistance are considered the most critical steps toward the implementation of sustainable and economically viable IPM strategies in tropical countries affected by whitefly pests and whitefly-transmitted viruses. PMID:17222696

Morales, Francisco J

2007-01-01

155

Tropical bacterial gastrointestinal infections.  

PubMed

The bacterial gastrointestinal infections cholera, salmonellosis, shigellosis, campylobacteriosis, and diarrheagenic Escherichia coli are prevalent in tropical regions. These diseases impose an immense cost and contribute significantly to childhood morbidity and mortality. Management is hampered by limited access to diagnostic facilities and by antimicrobial drug resistance. Rapid point-of-care assays aim to reduce treatment delay and encourage rational use of antimicrobial agents. Control through safe drinking water, good sanitation, and vaccination against typhoid and cholera in high-risk populations is recommended. Vaccines against other Shigella and diarrheagenic E coli infections are under development. PMID:22632648

Shakoor, Sadia; Zaidi, Anita K M; Hasan, Rumina

2012-06-01

156

Cloudsat tropical cyclone database  

NASA Astrophysics Data System (ADS)

CloudSat (CS), the first 94 GHz spaceborne cloud profiling radar (CPR), launched in 2006 to study the vertical distribution of clouds. Not only are CS observations revealing inner vertical cloud details of water and ice globally but CS overpasses of tropical cyclones (TC's) are providing a new and exciting opportunity to study the vertical structure of these storm systems. CS TC observations are providing first time vertical views of TC's and demonstrate a unique way to observe TC structure remotely from space. Since December 2009, CS has intersected every globally named TC (within 1000 km of storm center) for a total of 5,278 unique overpasses of tropical systems (disturbance, tropical depression, tropical storm and hurricane/typhoon/cyclone (HTC)). In conjunction with the Naval Research Laboratory (NRL), each CS TC overpass is processed into a data file containing observational data from the afternoon constellation of satellites (A-TRAIN), Navy's Operational Global Atmospheric Prediction System Model (NOGAPS), European Center for Medium range Weather Forecasting (ECMWF) model and best track storm data. This study will describe the components and statistics of the CS TC database, present case studies of CS TC overpasses with complementary A-TRAIN observations and compare average reflectivity stratifications of TC's across different atmospheric regimes (wind shear, SST, latitude, maximum wind speed and basin). Average reflectivity stratifications reveal that characteristics in each basin vary from year to year and are dependent upon eye overpasses of HTC strength storms and ENSO phase. West Pacific (WPAC) basin storms are generally larger in size (horizontally and vertically) and have greater values of reflectivity at a predefined height than all other basins. Storm structure at higher latitudes expands horizontally. Higher vertical wind shear (? 9.5 m/s) reduces cloud top height (CTH) and the intensity of precipitation cores, especially in HTC strength storms. Average zero and ten dBZ height thresholds confirm WPAC storms loft precipitation sized particles higher into the atmosphere than in other basins. Two CS eye overpasses (32 hours apart) of a weakening Typhoon Nida in 2009 reveal the collapse of precipitation cores, warm core anomaly and upper tropospheric ice water content (IWC) under steady moderate shear conditions.

Tourville, Natalie D.

157

Tropical Atlantic Aerosols  

NSDL National Science Digital Library

The atmosphere is a mixture of gases including nitrogen, oxygen, carbon dioxide and other trace gases. Additionally, the atmosphere contains small, suspended liquid and particle matter called aerosols. Aerosols come from various sources, both natural and anthropogenic (man-made). Aerosols are important to study and monitor because they have direct and indirect effects on regional weather and global climate. In this lesson, students will use real satellite data to determine where the greatest concentrations of aerosols are located during the course of a year in the tropical Atlantic region and their source of origin.

158

Gastrointestinal pathogens in rodents overwintering in human facilities around Uppsala, Sweden.  

PubMed

Rodents often live in close association with anthropogenic environments, offering rodent-associated pathogens numerous opportunities for transmission to humans. We screened for zoonotic gastrointestinal pathogens in rodents caught during autumn/winter in human dwellings in rural areas surrounding Uppsala, Sweden. We detected Campylobacter jejuni, Giardia sp., and Cryptosporidium sp. in rodent intestines. PMID:23778637

Lõhmus, Mare; Albihn, Ann

2013-07-01

159

The formation of tropical cyclones  

Microsoft Academic Search

Summary This paper attempts a synthesis of new observations and new concepts on how tropical cyclone formation occurs. Despite many worthy observational and numerical modeling studies in recent decades, our understanding of the detailed physical processes associated with the early stages of tropical cyclone formation is still inadequate; operational forecast skill is not very high. Although theoretical ideas cover a

W. M. Gray

1998-01-01

160

Structure of Developing Tropical Cyclones  

Microsoft Academic Search

Considerable progress has been made in the numerical modeling of tropical cyclones. The very high resolution now routinely used in research models allows realistic simulation of eyewall structure and breakdown, vortex Rossby waves, and numerous other processes that were beyond the capability of previous generations of models. At least one aspect of tropical cyclones, however, has not been reproduced in

J. E. Molinari

2006-01-01

161

Botany, Chemistry, and Tropical Development.  

ERIC Educational Resources Information Center

|Examines the role played by botany and chemistry in the development, exploitation, and later deterioration of tropical economies. Although near equals in 19th-century international trade, the development of synthetics by European scientists in the early 20th century crippled the tropical economies. Research, innovation, and investment protected…

Headrick, Daniel R.

1996-01-01

162

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

163

Conservation of tropical plant species  

Technology Transfer Automated Retrieval System (TEKTRAN)

This book is designed to provide a review of the methods and current status of conservation of many tropical plant species. Future perspectives of conservation of tropical species will also be discussed. The section on methods covers the range of conservation techniques, in situ, seed banking, in vi...

164

Tropical Cyclones - Central Pacific (1981).  

National Technical Information Service (NTIS)

Brief descriptions are given of Tropical Storm Greg (August 20-22, 1981) and Tropical Storm Jova (September 18-20, 1981) which took place in the Central Pacific. Verification statistics show that the 24-hour Central Pacific Hurricane Center (CPHC) forecas...

A. K. T. Chun

1982-01-01

165

Wind characteristics of tropical thunderstorms  

Microsoft Academic Search

Measurements obtained from a wind and rain monitoring stations set-up in Singapore, a place with frequent tropical thunderstorms, are reported. Wind speeds and wind directions at five levels on a 20m mast are continuously recorded with the simultaneous monitoring of rainfall intensity. Most of the higher gust speeds are observed to occur during tropical thunderstorms, which suggests that thunderstorm wind

Edmund C. C Choi

2000-01-01

166

ASSESSMENT OF HOST RESISTANCE TO INFECTION WITH RODENT MALARIA  

EPA Science Inventory

Resistance to malaria infection is known to require an intact immune system. his chapter presents an overview of rodent malaria, the host response to infection and methods for assessing infection in rats and mice....

167

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

168

40 CFR 798.5450 - Rodent dominant lethal assay.  

Code of Federal Regulations, 2013 CFR

...ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT (CONTINUED) HEALTH EFFECTS TESTING GUIDELINES Genetic Toxicity § 798.5450 Rodent dominant lethal assay. (a) Purpose. Dominant lethal (DL) effects cause...

2013-07-01

169

40 CFR 798.5460 - Rodent heritable translocation assays.  

Code of Federal Regulations, 2013 CFR

...ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT (CONTINUED) HEALTH EFFECTS TESTING GUIDELINES Genetic Toxicity § 798.5460 Rodent heritable translocation assays. (a) Purpose. This test detects transmitted...

2013-07-01

170

Occurrence of ectoparasites on rodents in Sukhothai Province, northern Thailand.  

PubMed

A survey of ectoparasites on rodents was carried out bimonthly from April 2008 to March 2009 in 3 districts of Sukhothai Province, northern Thailand. A total of 130 rodents comprising 8 species of hosts were captured and examined for ectoparasites. The hosts examined were Bandicota indica, Bandicota savilei, Rattus losea, Rattus rattus, Rattus exulans, Rattus norvegicus, Menetes berdmorei and Tamiops mcclellandii. Ninety-seven ectoparasites were collected: 1 species of tick (Hemaphysalis bandicota), 2 species of mites (Laelaps nuttali and Laelaps echidninus), and 1 species of flea (Xenopsylla cheopis) were identified. The infestation rates by ticks, mites and fleas on the rodents were 0.77, 5.38 and 6.15%, respectively. Monitoring the rodent population and their ectoparasites is important for future planning of prevention and control of zoonotic diseases in the area. PMID:21329306

Changbunjong, Tanasak; Weluwanarak, Thekhawet; Chamsai, Tatiyanuch; Sedwisai, Poonyapat; Ngamloephochit, Seni; Suwanpakdee, Sarin; Yongyuttawichai, Plern; Wiratsudakul, Anuwat; Chaichoun, Kridsada; Ratanakorn, Parntep

2010-11-01

171

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

172

Dual captures of Colorado rodents: implications for transmission of hantaviruses.  

PubMed Central

We analyzed dual-capture data collected during longitudinal studies monitoring transmission and persistence of Sin Nombre virus in rodents in Colorado. Our data indicate that multiple captures (two or more rodents captured in a single trap) may not be random, as indicated by previous studies, but rather the result of underlying, species-specific social behavior or cohesiveness. In the pairs we captured, most often, rodents were of the same species, were male, and could be recaptured as pairs. Therefore, dual captures of rodents, which are unusual but not rare, tend to occur among certain species, and appear to be nonrandom, group-foraging encounters. These demographic and ecologic characteristics may have implications for the study of the transmission of hantaviruses.

Calisher, C. H.; Childs, J. E.; Sweeney, W. P.; Canestrop, K. M.; Beaty, B. J.

2000-01-01

173

Investigation and characterization of the frozen feeder rodent industry in Texas following a multi-state Salmonella Typhimurium outbreak associated with frozen vacuum-packed rodents.  

PubMed

A multi-state outbreak investigation of Salmonella Typhimurim cases associated with pet snakes and the frozen vacuum-packed rodents used to feed them identified a Texas frozen feeder rodent facility (Supplier A) as the source of the Salmonella-infected frozen rodents. Texas authorities collected samples directly from Supplier A. Seven Salmonella-positive samples out of 49 environmental swabs were found and one adult mouse out of 88 frozen feeder rodents was Salmonella-positive by culture. No Salmonella strains were isolated from rodent feeds. The pulsed-field gel electrophoresis (PFGE) subtype patterns of S. Typhimurium isolates from feeder rodent and environment samples were indistinguishable from the outbreak strain isolated from humans. A follow-up investigation was performed on all additional feeder rodent facilities identified in Texas. Salmonella was isolated at one of four facilities; seven of 100 rodent samples were positive for Salmonella at this facility. The serotype S. I 4,[5],12:i:- was isolated from seven feeder rodent samples, and PFGE patterns of the seven isolates were indistinguishable. As observed in the initial outbreak investigation, no Salmonella were cultured from rodent feeds at any of the facilities. The feeder rodent industry is an insufficiently recognized industry in the United States. Outbreak investigation and testing of additional feeder rodent facilities in Texas indicate that further evaluation of feeder rodent facilities as a source of Salmonella for pet snakes and humans is warranted. PMID:18811909

Lee, K M; McReynolds, J L; Fuller, C C; Jones, B; Herrman, T J; Byrd, J A; Runyon, M

2008-10-01

174

Distribution and abundance of small rodents in Croatian forests  

Microsoft Academic Search

The relative abundance and the population development of small rodents were investigated on 17 sites in Croatian forests from September 1999 through June 2003. Common snap traps were set for two or three nights along transect lines in different forest types. In 27,598 trap–nights, 2,151 specimens were trapped. Small rodents were present in up to 45% of the traps in

J. Margaleti?; M. Boži?; M. Grubeši?; M. Glavaš; W. Bäumler

2005-01-01

175

Cheek pouch capacities and loading rates of heteromyid rodents  

Microsoft Academic Search

Rodents of the family Heteromyidae are proficient gatherers and hoarders of seeds. A major component of their adaptive specialization\\u000a for harvesting and transporting seeds is their spacious, fur-lined cheek pouches. Precise measurements of cheek pouch capacities\\u000a are essential if ecologists are to understand the foraging ecology, possible constraints on locomotion patterns, and competitive\\u000a relationships of heteromyid rodents. To measure the

Stephen B. Vander Wall; William S. Longland; Sanjay Pyare; Joseph A. Veech

1997-01-01

176

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

2008-02-11

177

Object recognition memory and the rodent hippocampus.  

PubMed

In rodents, the novel object recognition task (NOR) has become a benchmark task for assessing recognition memory. Yet, despite its widespread use, a consensus has not developed about which brain structures are important for task performance. We assessed both the anterograde and retrograde effects of hippocampal lesions on performance in the NOR task. Rats received 12 5-min exposures to two identical objects and then received either bilateral lesions of the hippocampus or sham surgery 1 d, 4 wk, or 8 wk after the final exposure. On a retention test 2 wk after surgery, the 1-d and 4-wk hippocampal lesion groups exhibited impaired object recognition memory. In contrast, the 8-wk hippocampal lesion group performed similarly to controls, and both groups exhibited a preference for the novel object. These same rats were then given four postoperative tests using unique object pairs and a 3-h delay between the exposure phase and the test phase. Hippocampal lesions produced moderate and reliable memory impairment. The results suggest that the hippocampus is important for object recognition memory. PMID:20028732

Broadbent, Nicola J; Gaskin, Stephane; Squire, Larry R; Clark, Robert E

2009-12-22

178

Utility of recycled bedding for laboratory rodents.  

PubMed

Animal facilities generate a large amount of used bedding containing excrement as medical waste. We developed a recycling system for used bedding that involves soft hydrothermal processing. In this study, we examined the effects of bedding type on growth, hematologic and serum biochemical values, and organ weights of female and male mice reared on either recycled or fresh bedding from 3 to 33 wk of age. Neither growth nor physiology differed between mice housed on recycled bedding compared with fresh bedding. When 14-wk-old mice were bred, litter size and total number of weaned pups showed no significant differences between animals raised on recycled or fresh bedding. Because bedding type influences the environment within cages and animal rooms, we evaluated particulate and ammonia data from cages and animal rooms. Values were significantly lower from cages and rooms that used recycled bedding than from those using fresh bedding, thus indicating that recycled bedding has the potential to improve the environment within both cages and animal rooms. Overall, this study revealed that recycled bedding is an excellent material for use in housing laboratory rodents. Specifically, recycled bedding may reduce medical waste and maintain healthy environments within cages and animal rooms. PMID:19653951

Miyamoto, Toru; Li, Zhixia; Kibushi, Tomomi; Okano, Shinya; Yamasaki, Nakamichi; Kasai, Noriyuki

2009-07-01

179

Tropical chronic pancreatitis  

PubMed Central

Tropical chronic pancreatitis (TCP) is a juvenile form of chronic calcific non-alcoholic pancreatitis, seen almost exclusively in the developing countries of the tropical world. The classical triad of TCP consists of abdominal pain, steatorrhoea, and diabetes. When diabetes is present, the condition is called fibrocalculous pancreatic diabetes (FCPD) which is thus a later stage of TCP. Some of the distinctive features of TCP are younger age at onset, presence of large intraductal calculi, more aggressive course of the disease, and a high susceptibility to pancreatic cancer. Pancreatic calculi are the hallmark for the diagnosis of TCP and in non-calcific cases ductal dilation on endoscopic retrograde cholangiopancreatography, computed tomography, or ultrasound helps to identify the disease. Diabetes is usually quite severe and of the insulin requiring type, but ketosis is rare. Microvascular complications of diabetes occur as frequently as in type 2 diabetes but macrovascular complications are uncommon. Pancreatic enzyme supplements are used for relief of abdominal pain and reducing the symptoms related to steatorrhoea. Early diagnosis and better control of the endocrine and exocrine dysfunction could help to ensure better survival and improve the prognosis and quality of life of TCP patients.

Barman, K; Premalatha, G; Mohan, V

2003-01-01

180

Divergent patterns of breakpoint reuse in Muroid rodents.  

PubMed

Multiple Genome Rearrangement (MGR) analysis was used to define the trajectory and pattern of chromosome rearrangement within muroid rodents. MGR was applied using 107 chromosome homologies between Mus, Rattus, Peromyscus, the muroid sister taxon Cricetulus griseus, and Sciurus carolinensis as a non-Muroidea outgroup, with specific attention paid to breakpoint reuse and centromere evolution. This analysis revealed a high level of chromosome breakpoint conservation between Rattus and Peromyscus and indicated that the chromosomes of Mus are highly derived. This analysis identified several conserved evolutionary breakpoints that have been reused multiple times during karyotypic evolution in rodents. Our data demonstrate a high level of reuse of breakpoints among muroid rodents, further supporting the "Fragile Breakage Model" of chromosome evolution. We provide the first analysis of rodent centromeres with respect to evolutionary breakpoints. By analyzing closely related rodent species we were able to clarify muroid rodent karyotypic evolution. We were also able to derive several high-resolution ancestral karyotypes and identify rearrangements specific to various stages of Muroidea evolution. These data were useful in further characterizing lineage-specific modes of chromosome evolution. PMID:20033182

Mlynarski, E E; Obergfell, C J; O'Neill, M J; O'Neill, R J

2009-12-22

181

Protection of Geophysical, Communication and Power Transmission Cable Against Rodent Species Attack by R-55 Rodent Repellent Treatment.  

National Technical Information Service (NTIS)

The chemical, tert butylsulfenyl dimethyldithiocarbamate (designated R-55 Rodent Repellent), which has a high degree of repellency to a number of animal and insect species was approved for the protective treatment of geophysical cables against specific ro...

T. H. Mailen R. E. Stansbury

1966-01-01

182

World Health Organization: Tropical Diseases  

NSDL National Science Digital Library

This World Health Organization website feature focuses on tropical diseases. For visitors unfamiliar with which diseases out there are considered tropical, this website provides informative fact sheets on fourteen different tropical diseases. To view the factsheets, visitors should click on "Fact Sheets on Tropical Diseases", under the General Information heading near the top of the homepage. The fact sheets cover topics such as "Symptoms", "Transmission", "Treatment", "Prevention", "Economic Cost", and "Diagnosis". Under the "Multimedia" heading near the top of the homepage, visitors can click on the link "10 Facts on Neglected Tropical Diseases", to be taken to a slide show, via the link near the bottom of the page entitled "Read More About Neglected Tropical Diseases". The slide show explains that a neglected tropical disease is a disease that costs little to prevent, does not spread to wealthy areas and is of little priority to pharmaceutical companies when it comes to research and development of medicines for them. Under the Statistics heading near the bottom of the homepage, visitors can click on a link to get to the "Global Health Database", which contains "standardized data and statistics for infectious diseases at country, regional, and global levels."

183

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

2011-08-08

184

Role of equatorial waves in tropical cyclogenesis  

Microsoft Academic Search

Tropical cyclones typically form within preexisting wavelike disturbances that couple with convection. Using Tropical Rainfall Measuring Mission (TRMM) multisatellite rainfall estimates, this study determines the relative number of tropical cyclones that can be attributed to various wave types, including the Madden--Julian oscillation (MJO), Kelvin waves, equatorial Rossby (ER) waves, mixed Rossby--gravity (MRG) waves, and tropical depression (TD)-type disturbances. Tropical cyclogenesis

Carl J. Schreck III

2010-01-01

185

[Small rodents in the forest ecosystem as infectious disease reservoirs].  

PubMed

Due to numerousness of populations and width of ecologic valence, small rodents are important parts of almost any forest ecosystem. The represent an important animal group, which connects primary makers with higher trophic levels. They transmit various infectious diseases dangerous for the health of people and domestic and wild animals (trichinosis, leptospirosis, tick encephalitis, Lyme disease, hemorrhagic fever with renal syndrome, etc.). The following species of small rodents live in forest ecosystems of Croatia: Chletrionomys glareolus Schreib., Arvicola terrestris L, M. subterraneus de Sel., M. arvalis Pall., M. agrestis L, M. multiplex Fat., Apodemus agrarius Pall., A. sylvaticus L. and A. flavicollis Melch. Small rodents transmit causative agents of diseases in active (excretion products) of passive (ectoparasites and endoparasites) ways. Their multiplication potential is quite high. Transmission of certain disease sometimes takes place extremely fast due to the high number of rodents, their high movability and distribution, and the fact that they easily get in touch with men and domestic and wild animals. The number of population of each species is directly influenced by abiotic and biotic factors and changes during one year and in a several year period. In a year when the influence of ecologic factors is favorable, it is presumed that the number of these rodents will significantly increase, by which the danger of their damaging effect also increases. The following factors influence the increase of a small rodent population: number and physiologic condition of the population, meteorologic conditions, habitat, food sources, natural enemies, and diseases. The occurrence of an epidemic is closely connected to the number and infectivity of causative agents. Regular control of the number of rodent population and their infectivity can help in planning preventive epidemiologic and sanitary measures to preclude the occurrence of epidemics and individual cases of disease among animals and humans who come in contact with forest (forest workers, holiday makers, hikers, soldiers, tourists, etc.). PMID:15011471

Margaleti?, Josip

2003-01-01

186

Observing Guidance for Tropical Cyclones.  

National Technical Information Service (NTIS)

Tropical cyclones (TCs), including hurricanes in the Atlantic and typhoons in the Western Pacific, are of great military and civilian interest around the world. In order to improve the prediction of TC intensity, structure, and track, THe Observing-system...

C. Amerault C. A. Reynolds H. Jin J. D. Doyle

2009-01-01

187

Acuste Pneumonia in Tropical Infections.  

National Technical Information Service (NTIS)

Pulmonary lesions were seen in nine patients with diseases endemic to the tropics. Five patients with Plasmodium falciparum malaria and one patient each with leptospirosis, scrub typus, bubonic plague, and typoid fever developed pulmonary infiltrates duri...

M. J. Tong D. B. Youel C. L. Cotten

1971-01-01

188

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

189

Public health importance of rodents in South America  

PubMed Central

Indigenous South American rodents are abundant, varied, and adaptable, and occupy most of the available natural habitats. Knowledge of their taxonomy and biology is generally superficial. Near human habitations the introduced Rattus and Mus are common and their contacts with man are often close. Cities in South America are expanding to keep pace with increases in the human population and hitherto virgin land is being settled or cleared for food production. Thus domestic rodents are brought into contact with indigenous species and the inevitable exchange of parasites may then produce unpredictable threats to human health. The role of both wild and domestic rodents in the transmission of certain infectious diseases, such as plague, sylvatic Venezuelan encephalitis, South American haemorrhagic fevers, murine typhus, and cutaneous leishmaniasis, is well established. The involvement of rodents in some other diseases, such as leptospirosis, American trypanosomiasis, South American hydatid disease, and vesicular stomatitis, is less well understood. In certain other infections, including bartonellosis and the South American spotted fevers, a wild rodent reservoir is inferred but not yet identified.

Mackenzie, R. B.

1972-01-01

190

Chemosterilant action of trimethylphosphate in rodents.  

PubMed

Trimethylphosphate, the simplest tri-alkyl ester of phosphoric acid, produces marked antifertility effects in experimental male rodents (Jackson and Jones, 1968). The predominant effect is the "functional" sterilizing action involving spermatids from which intact motile but incompetent sperm continue to be produced. Relatively high doses are required in the mouse (5 X 1 gm/kg orally), whereas it is effective in the rat at 1/10 of this level. Trimethylphosphate is remarkable in that it possesses no anticholinesterase activity, is freshly soluble and stable in water, is effective orally, and has a high level of tolerance. Whereas 500 mg/kg orally render male rats sterile for the ensuing 3 weeks, 5 times this amount, although tolerable, completely disorganizes spermatogenesis without damaging tubular architecture. Such treated rats remain infertile for 20-25 weeks, apparently retaining sexual activity, though a proportion appear to be more permanently sterilized. Rats treated weekly at 5 X 100 mg/kg orally for over 1 year have remained sterile but recover fertility 3-5 weeks from terminating treatment. "Side effects" so far observed are a sedative action and, towards 1 year of treatment, hind leg paresis, although 5 times this dose rate caused progressive loss in weight. Using phosphorus-32-trimethylphosphate the sole phosphorus-containing metabolite is dimethylphosphate (Jackson and Jones, 1968), which has no antifertility activity. With carbon-14-trimethylphosphate, S-methyl cysteine was identified as a urinary metabolite, indicating that trimethylphosphate is involved, at least in its detoxification process, as an alkylating agent. The antifertility action of trimethylphosphate is probably related to methyl alkylation. This would bring it into line with the methyl ester of methanesulphonic acid which also produces the "functional" type of sterility in rats and mice (Jackson, 1964). Like methyl methanesulphonate (Partington and Bateman, 1964), trimethylphosphate in substerilizing doses induces so-called dominant lethal mutations. Preliminary structure/activity studies have shown that tri-n-propyl- and tri-iso-propylphosphates do not affect the fertility of male mice (5 X 1 gm/kg orally). Both these esters together with tri-n-propyl- and tri-n-butyl-phosphates still have the capacity to alkylate, and like trimethylphosphate, the only metabolites in the rat were the di-alkylphosphates and corresponding S-alkyl cysteines. Whereas all these substances interact with cysteine in vitro, only trimethylphosphate reacts readily with glutathione. This might be pertinent to its biological activity. PMID:12332193

Jones, A R; Jackson, H

1969-10-01

191

Rodent models for HIV-associated neurocognitive disorders  

PubMed Central

Human immunodeficiency virus (HIV)-associated neurocognitive disorders (HAND) reflect the spectrum of neural impairments seen during chronic viral infection. Current research efforts focus on improving antiretroviral and adjunctive therapies, defining disease onset and progression, facilitating drug delivery, and halting neurodegeneration and viral resistance. As HIV is species-specific, generating disease in small animal models has proved challenging. After two decades of research, rodent HAND models now include those containing a human immune system. Antiviral responses, neuroinflammation and immunocyte blood-brain barrier (BBB) trafficking follow HIV infection in these rodent models. Here, we review these and other rodent models of HAND and discuss their unmet potential in reflecting human pathobiology and in facilitating disease monitoring and therapeutic discoveries.

Gorantla, Santhi; Poluektova, Larisa; Gendelman, Howard E.

2012-01-01

192

A Standardized Technique for Performing Thrombelastography in Rodents  

PubMed Central

Introduction Thrombelastography (TEG), employed in liver transplant and cardiac surgery for nearly 50 years, has recently been applied to the trauma setting. Rodents are employed widely for shock research, but are known to have differences in their coagulation system compared to humans. Consequently, the appropriate technique for performing TEG requires modification of the standard clinical protocol. Materials and Methods Thrombelastography (TEG) was performed with blood collected from the femoral artery of rodents, and technical modifications were tested to optimize results. Results Analysis of citrated whole blood using TEG revealed a more rapid onset of coagulation in rats compared to humans. The reference ranges of TEG parameters for Sprague-Dawley rats are detailed. Discussion Citrated native whole blood is the optimal TEG method in the assessment of coagulation in rodents. Investigators using TEG for research purposes should establish their own reference ranges in order to determine normal values for their target population.

Wohlauer, Max V.; Moore, Ernest E.; Harr, Jeffrey; Gonzalez, Eduardo; Fragoso, Miguel; Silliman, Christopher C.

2011-01-01

193

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

194

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

195

Rodents for comparative aging studies: from mice to beavers  

PubMed Central

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.

Bozzella, Michael J.; Seluanov, Andrei

2008-01-01

196

Colonisation and shedding of Lawsonia intracellularis in experimentally inoculated rodents and in wild rodents on pig farms.  

PubMed

Lawsonia intracellularis is an intracellular bacterium causing proliferative enteropathy in various animal species, and is considered an economically important pathogen of pigs. Rats and mice have been implicated as external vectors for a wide range of pig pathogens, including L. intracellularis. Previous studies have demonstrated L. intracellularis infection and proliferative enteropathy in rodents, but did not show the duration of shedding or the number of L. intracellularis shed by infected rodents, and therefore the infection risk that rodents pose to pigs. In this study, the number of L. intracellularis shed in the faeces and intestinal mucosa of wild rats trapped on pig farms was determined by a quantitative real time polymerase chain reaction assay. The prevalence of L. intracellularis in wild rats trapped on pig farms with endemic proliferative enteropathy (PE) was very high (? 70.6%), and large numbers of L. intracellularis were shed (10(10)/g of faeces) in a small proportion of wild rats. The duration of colonisation in laboratory rats and mice challenged with porcine isolates of L. intracellularis was also shown. Faecal shedding of L. intracellularis persisted for 14-21 days in rats and mice that were mildly affected with histological lesions of PE. The humoral immune response to L. intracellularis persisted for 40 days in both species. This study demonstrates that rodents may be an important reservoir of L. intracellularis on piggeries, and hence rodent control is important in disease eradication programs on pig farms. PMID:21349664

Collins, A M; Fell, S; Pearson, H; Toribio, J-A

2011-02-01

197

Synanthropic rodents as possible reservoirs of shigatoxigenic Escherichia coli strains  

PubMed Central

Shigatoxigenic Escherichia coli (STEC) strains are worldwide zoonotic pathogen responsible for different cases of human disease including hemolytic uremic syndrome (HUS). Transmission of STEC to humans occurs through the consumption of food and water contaminated by faeces of carriers and by person-to-person contact. The objective of this study was two-fold: (1) to investigate whether synanthropic rodents are possible reservoirs of STEC in the urban area and (2) whether a particular genus out of synanthropic rodent is the principal carrier of STEC. One hundred and forty-five rodents were captured in Buenos Aires City. Screening for stx1/stx2 and rfbO157 was done by PCR from the confluence zone. STEC isolates were further characterized with biochemical tests by standard methods. Additional virulence factors (eae, ehxA, and saa) were also determined by PCR. Forty-one of the rodents were necropsied and sample of kidney and small and large intestine were taken for histopathological diagnosis. The samples sections were stained with hematoxylin-eosin, and observed by light microscopy to evaluate the systemic involvement of these species in natural infections. STEC was isolated from seven out of 27 suspect animals at screening. The following genotypes were found in the STEC strains: stx1/stx2/ehxA (1), stx2 (4), stx2/ehxA (1), stx2/ehxA/eae (1). Neither gross nor microscopic lesions compatible with those produced by Shiga toxin were observed in the studied organs of necropsied rodents. The bivariate analysis including the 145 rodent's data showed that the isolation of STEC is associated positively to Rattus genus. This synanthropic species may play a role in the transmissibility of the agent thus being a risk to the susceptible population. Their control should be included specifically in actions to dismiss the contamination of food and water by STEC in the urban area, as additional strategies for epidemiological control.

Blanco Crivelli, Ximena; Rumi, Maria V.; Carfagnini, Julio C.; Degregorio, Osvaldo; Bentancor, Adriana B.

2012-01-01

198

Antioxidants from tropical herbs.  

PubMed

Plants that contain high amounts of polyphenolic compounds are potential candidates for natural antioxidant sources. Studies are on going in the search for new sources of antioxidants. Not much data are available on the antioxidant capacity of tropical herbs. With this in mind, 19 commonly consumed Malaysian herbs were analyzed for their polyphenolic content and antioxidant activities. A majority of these plants have never been studied before with regards to their polyphenolic content and antioxidant activities. The shoots of Anacardium occidentale, the shoots and fruits of Barringtonia racemosa, Pithecellobium jiringa and Parkia speciosa had high polyphenolic contents (> 150 microg gallic acid equivalents/mg dried plant) and antioxidant activities when measured using the ferric reducing antioxidant power (FRAP) (>1.2 mM) and Trolox equivalent antioxidant capacity (TEAC) assays (>2.4 mM). A strong correlation was observed between the two antioxidant assays (FRAP vs TEAC) implying that the plants could both scavenge free radicals and reduce oxidants. There was also a strong correlation between the antioxidant activities and polyphenolic content suggesting the observed antioxidant activities were contributed mainly by the polyphenolics in the plants. PMID:20420325

Razab, Rasyidah; Abdul-Aziz, Azlina

2010-03-01

199

Tropical orographic rainfall regimes  

NASA Astrophysics Data System (ADS)

This study seeks to (1) examine the variables that influence precipitation mode and structure near complex terrain and (2) analyze the vertical and horizontal structure of precipitation systems in regions of complex terrain under current climate conditions, and how it may evolve in the future. For this study, we will examine 11 years (1998-2008) of data over the tropical Andes, Hawaii, Himalayas, Sierra Madre Occidental, and Western Ghats to determine which combination of atmospheric variables plays a crucial role in precipitation development and mode. We will compare NASA MERRA Data and NCEP-II Reanalysis Data to evaluate the robustness of the NASA MERRA dataset in determining dynamic and thermodynamic variables key for understanding orographic precipitation modes. We will then use NASA MERRA Data to evaluate how specific humidity, wind speed, and wind direction relative to the terrain effect the formation of precipitation in the regions of interest. TRMM radar (3B42) data will be used to determine precipitation mode and amount, which will be compared to the regimes based on the variables above. The second portion of the study will examine the vertical and horizontal structure of radar echoes in precipitation systems near these mountain ranges. We will examine how vertical structure within precipitation systems varies as a function of height and time of day using statistical analysis using the “precipitation feature” approach. Implications for characteristic variations in microphysical processes and rainfall production will be discussed, along with implications for the vertical structure of latent heating.

Reed, K. A.; Nesbitt, S. W.

2010-12-01

200

Adiaspiromycosis of an Apodemus agrarius captured wild rodent in Korea  

PubMed Central

Adiaspiromycosis is caused by pulmonary infection with Emmonsia. Inhalated spores of Emmonsia cause asymptomatic infection to necrogranulomatous pneumonia, depending on the burden of adiaspore and host immunity. For disease monitoring of wild rodents captured on Jeju Island in Korea, we examined the lung tissue of wild rodents histopathologically. Spores composed of thick three-layered walls were found following histopathological examination and were diagnosed as adiaspiromycosis. Adiaspiromycosis has been found in mammals in many parts of the world. To our knowledge, this is the first report of adiaspiromycosis of an Apodemus agrarius captured in Korea.

Kim, Tae-Hyoun; Han, Ju-Hee; Chang, Seo-Na; Kim, Dong-Su; Abdelkader, Tamer Said; Seok, Seung-Hyeok; Park, Jong-Hwan; Oh, Hong-Shik; Kim, Jong-Taek; Lee, Byoung-Hee; Shin, Jeong-Hwa; Kim, Jung-Hyun; Kim, Jong-Min

2012-01-01

201

Understanding phenotypic variation in rodent models with germline Apc mutations.  

PubMed

Adenomatous polyposis coli (APC) is best known for its crucial role in colorectal cancer suppression. Rodent models with various Apc mutations have enabled experimental validation of different Apc functions in tumors and normal tissues. Since the development of the first mouse model with a germline Apc mutation in the early 1990s, 20 other Apc mouse and rat models have been generated. This article compares and contrasts currently available Apc rodent models with particular emphasis on providing potential explanations for their reported variation in three areas: (i) intestinal polyp multiplicity, (ii) intestinal polyp distribution, and (iii) extraintestinal phenotypes. PMID:23580574

Zeineldin, Maged; Neufeld, Kristi L

2013-04-11

202

Tropical Cyclones of the North Atlantic Ocean, 1971-1980.  

National Technical Information Service (NTIS)

Contents: Characteristics of tropical cyclones; Classification of Atlantic Tropical Cyclones; Data sources; Accuracy of tracks and intensity classifications; North Atlantic Tropical Cyclone tracks; Frequency of North Atlantic Tropical Cyclones.

C. J. Neumann G. W. Cry E. L. Caso B. R. Jarvinen

1981-01-01

203

LANDSCAPE VARIATION IN DESERT RODENT COMMUNITY RESPONSE TO GRASS-SHRUBLAND ECOTONES  

Technology Transfer Automated Retrieval System (TEKTRAN)

Desert rodents exert strong effects on soil, vegetation, and other animals. It has been reported that the abundance and diversity of Chihuahuan Desert rodents increases with shrub encroachment accompanying desertification although grassland specialist species decline with loss of perennial grasses. ...

204

Rodent community landscape ecology in grassland-shrubland ecotones and gradients in the Chihuahuan Desert  

Technology Transfer Automated Retrieval System (TEKTRAN)

It is believed that the abundance and diversity of Chihuahuan Desert rodents increases with shrub encroachment accompanying desertification although grassland specialist species decline with loss of perennial grasses. It has been reported, however, that rodent population responses to spatial variati...

205

Rodent Population Densities and Food Habits in Arizona Ponderosa Pine Forests.  

National Technical Information Service (NTIS)

Habitat preference, effect of timber harvesting on population densities, and food habits were determined for small rodents inhabiting ponderosa pine in north-central Arizona. Forbs were the primary summer food item for all rodent species. Seeds and flower...

J. G. Goodwin C. R. Hungerford

1979-01-01

206

The Tropical Transition of Western Pacific Tropical Storm 16W  

NASA Astrophysics Data System (ADS)

The breaking of synoptic scale Rossby waves is a common occurrence along the extratropical waveguide. During such events, stratospheric intrusions into the troposphere of high potential vorticity (PV) air retain only a thin connection to the stratospheric body of air. In some cases, these so-called PV streamers can extend a significant distance equatorward, concomitantly serving as an atmospheric destabilization mechanism. As such, they have been observed to play a role in heavy precipitation events and subtropical cyclogenesis. Intriguing evidence that PV streamers might also serve as extratropical precursors to tropical cyclogenesis events exists in the form of composite and case-study analyses of a limited number of Atlantic events. For this to occur, the system must transition from a cold to a warm core system. This process has been termed tropical transition (TT). The Tropical Cyclone Structure (TCS) 2008 field program provided a unique opportunity to study the TT process in the western Pacific basin. TCS037 was a storm system identified in realtime during the field program as a possible candidate for a TT-like event: deep convection was associated with an upper-level disturbance emanating from the extratropics. This study examines the evolution of TCS037 from this early stage of deep convection in an environment with significant vertical wind shear (a condition detrimental to tropical cyclone formation) to a weak tropical storm. Specifically, we invoke PV and Lagrangian frameworks to examine the processes via which (i) a distinct PV streamer served as a forcing mechanism for deep convection, and (ii) near-continuous convection aided in the erosion of the deleterious vertical wind shear, ultimately resulting in a conducive local environment for tropical cyclogenesis to ensue.

Schoenenberger, F.; Moore, R.; Martius, O.

2010-09-01

207

[Epilepsy in tropical areas].  

PubMed

Epilepsy in tropical areas, and in developing countries more generally, has certain specific characteristics (in particular its severity) which help to explain why this is still a major public health problem. The authorities often neglect this disease, even though numerous alarms have been raised by national leagues against epilepsy and by the World Health Organization, in order to bring epilepsy "out of the shadows". The prevalence is two to ten times higher and the incidence rate twice that in western countries. The mortality rate is very high, and many patients do not have access to appropriate treatment. In addition to the usual etiologies, certain causes are more common or specific to patients in poor countries, such as perinatal disorders and parasitic diseases (particularly cerebral malaria and neurocysticercosis). The impact of consanguinity is difficult to assess. Many associations against epilepsy have been created. Specific standardized guidelines have been written, validated and translated into several languages but they are under-utilized. A common language needs to be found between patients and caregivers, because of the numerous dialects spoken by ethnic groups, and the hidden meanings of the words used in this disease, where interpretations and perceptions cannot be dissociated from local culture. In most developing countries epilepsy is still considered a dangerous transmissible disease, and people with epilepsy are stigmatized. Specific training programs for healthcare personnel are needed, and efforts must be made to improve awareness among the population and the authorities. Some such programs are being supported by the pharmaceutical industry. This is particularly crucial in countries where counterfeit drugs are frequent and access to medicines is limited. Indeed, up to 80 % of people with epilepsy are treated poorly or not at all, and phenobarbitone is still the most widely used drug. PMID:19238785

Dumas, Michel; Preux, Pierre-Marie

2008-05-01

208

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

209

Leaf Decomposition in a Tropical Rainforest Stream.  

National Technical Information Service (NTIS)

Fungi play an important part in leaf litter decomposition in terrestrial ecosystems in both temperate and tropical regions. There are few published reports dealing with decomposition in running waters, and no work has been done in tropical streams. Result...

D. E. Padgett

1975-01-01

210

Tropical Cyclones 1989 - Central North Pacific.  

National Technical Information Service (NTIS)

Contents: Central north pacific tropical cyclone data 1989; Tropical depression FOUR-E and FIVE-E; Hurricane Dalilia; Hurricane Dalilia - actual vs best track error; Hurricane Dalilia - 24 hour forecast verification; Hurricane Dalilia - 36 hour forecast v...

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

1990-01-01

211

Tropical Cyclones, Central North Pacific, 1993.  

National Technical Information Service (NTIS)

There were two tropical depressions, one tropical storm, and two hurricanes that affected the Honolulu Central Pacific Hurricane Center's (CPHC) area of responsibility in 1993 (all of which occurred during the months of July and August). All of these trop...

G. H. Trapp A. L. Garza H. E. Rosendal B. Hablutzel A. K. T. Chun

1994-01-01

212

Eastern North Pacific Tropical Cyclones, 1973.  

National Technical Information Service (NTIS)

Tropical cyclone activity in the eastern North Pacific Ocean began June 1 and continued through October 9. It was one of the least active seasons since information from operational satellites, which completely cover the tropical areas, became available to...

1974-01-01

213

Rainfall Pattern over the Tropical Rain Forest.  

National Technical Information Service (NTIS)

Presented in viewgraph format, reviews of water cycle associated with tropical rain forest are given. Topics addressed include: water cycle model over the tropical rain forest; Rutter Model; Manta Model; Global Climate Model (GCM); relation of rainfall to...

H. Tanaka

1990-01-01

214

Rodents and Leptospira transmission risk in Terceira island (Azores)  

Microsoft Academic Search

The role of rodents as Leptospira renal carriers in Terceira island was evaluated (1993–1995) through kidney culture and serology [microscopic aglutination test (MAT)] of 94 mice and rats. Fifty-nine animals were positive (n = 41 by serology + culturing; n = 11 serology; n = 7 culturing), presenting a wide distribution in man-made and natural areas. House mice had the

M. Collares-Pereira; M. L. Mathias; M. Santos-Reis; M. G. Ramalhinho; P. Duarte-Rodrigues

2000-01-01

215

Effects of cerebral metabolic enhancers on brain function in rodents  

Microsoft Academic Search

The effects of cerebral metabolic enhancers (indeloxazine, bifemelane, idebenone, and nicergoline) on reserpine-induced hypothermia, the immobility period in forced swimming tests, and passive avoidance learning behavior were compared with the effects of amitriptyline in rodents. Indeloxazine, bifemelane, and amitriptyline antagonized hypothermia in mice given reserpine. Indeloxazine and amitriptyline decreased the immobility period in mice in the forced swimming test in

Koichiro Takahashi; Minoru Yamamoto; Masanori Suzuki; Yukiko Ozawa; Takashi Yamaguchi; Hirofumi Andoh; Kouichi Ishikawa

1995-01-01

216

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

217

Cytokine-independent repression of rodent Ntcp in obstructive cholestasis  

Microsoft Academic Search

Cholestatic liver injury is associated not only with accumulation of bile acids but also with activation of proinflammatory cytokines. Common bile duct ligation (CBDL) induces sustained downregulation of the Na(+)\\/taurocholate cotransporter (Ntcp) in rodent liver. Although repression of Ntcp during endotoxemia is cytokine mediated, it is unclear whether inflammatory cytokines contribute to this downregulation in obstructive cholestasis. Cytokine inactivation in

Andreas Geier; Gernot Zollner; Christoph G. Dietrich; Martin Wagner; Peter Fickert; Helmut Denk; Nico van Rooijen; Siegfried Matern; Carsten Gartung; Michael Trauner

2005-01-01

218

Neurobehavioral actions of coumestrol and related isoflavonoids in rodents  

Microsoft Academic Search

Isoflavonoids are plant estrogens that are increasingly advocated as a natural alternative to estrogen replacement therapy (ERT) and are available as dietary supplements. As weak estrogen agonists\\/antagonists with a range of other enzymatic activities, the isoflavonoids provide a useful model for the actions of endocrine disruptors. This paper reviews the responses of rodents to diets containing coumestrol or an isoflavone

Patricia L Whitten; Heather B Patisaul; Larry J Young

2002-01-01

219

Complexity in rodent community responses to grassland-shrubland transitions  

Technology Transfer Automated Retrieval System (TEKTRAN)

It is believed that the abundance and diversity of Chihuahuan Desert rodents increases with shrub encroachment accompanying desertification although grassland specialist species decline with loss of perennial grasses. It has been reported, however, that a suite of biotic-abiotic interactions may inf...

220

Synthesis of Polymerized Melanin by Cryptococcus neoformans in Infected Rodents  

Microsoft Academic Search

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

ANGEL L. ROSAS; JOSHUA D. NOSANCHUK; MARTA FELDMESSER; GARY M. COX; HENRY C. MCDADE; ARTURO CASADEVALL

2000-01-01

221

RODENT CONSUMPTION OF FOURWING SALTBUSH SEEDS AND SEEDLINGS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Fourwing saltbush (Atriplex canescens) is one of the most valuable shrubs in arid and semi arid rangelands. Due to its' value it is a widely used native shrub in the rehabilitation of western rangelands. Granivorous rodents play an important role in the seed harvesting and dispersal of many browse...

222

Arenavirus antibody in rodents indigenous to coastal southern California.  

PubMed

The purpose of this study was to extend our knowledge on the geographic and natural rodent host ranges of New World arenaviruses in California. Sera from 1,094 sigmodontine and 112 murine rodents were tested for antibody against Whitewater Arroyo and Amapari viruses. Antibody was found in 55 (4.6%) of the 1,206 rodents: 4 from northwestern San Diego County, 3 from Los Angeles County, and 48 from Orange County. The antibody-positive rodents included 8 (7.8%) of 103 Neotoma fuscipes, 1 (0.6%) of 180 Neotoma lepida, 1 (3.1%) of 32 Peromyscus boylii, 8 (11.0%) of 73 Peromyscus californicus, 1 (1.2%) of 85 Peromyscus eremicus, 30 (8.5%) of 353 Peromyscus maniculatus, and 6 (2.2%) of 268 Reithrodontomys megalotis. This study provides the first evidence that New World arenaviruses occur in Los Angeles and Orange counties and northwestern San Diego County, and the first evidence that Peromyscus and Reithrodontomys species are naturally infected with New World arenaviruses. PMID:11289675

Bennett, S G; Milazzo, M L; Webb, J P; Fulhorst, C F

2000-05-01

223

High Diversity of RNA Viruses in Rodents, Ethiopia  

PubMed Central

We investigated synanthropic small mammals in the Ethiopian Highlands as potential reservoirs for human pathogens and found that 2 rodent species, the Ethiopian white-footed mouse and Awash multimammate mouse, are carriers of novel Mobala virus strains. The white-footed mouse also carries a novel hantavirus, the second Murinae-associated hantavirus found in Africa.

Meheretu, Yonas; Cizkova, Dagmar; Tesikova, Jana; Welegerima, Kiros; Tomas, Zewdneh; Kidane, Dawit; Girmay, Kokob; Schmidt-Chanasit, Jonas; Bryja, Josef; Gunther, Stephan; Bryjova, Anna; Leirs, Herwig

2012-01-01

224

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

225

Glucocorticoid Stimulates Primate but Inhibits Rodent ?-Fetoprotein Gene Promoter  

Microsoft Academic Search

Glucocorticoids inhibit rodent ?-fetoprotein (AFP) gene activity but stimulate expression of the human homologue. Like human, activity of the AFP promoter from other primates was stimulated by the synthetic glucocorticoid dexamethasone (Dex) in various cell lines. A glucocorticoid responsive element (GRE) is located within 180 bp upstream of the transcription initiation site of all AFP genes examined. Comparative analysis of

Hidekazu Nakabayashi; Yoshikazu Koyama; Masaharu Sakai; Hong Mei Li; Norman C. W. Wong; Shinzo Nishi

2001-01-01

226

A simple mathematical model of rodent population cycles  

Microsoft Academic Search

A simple mathematical rate equation model is presented, which describes the observed cycles in rodent populations. The population is assumed to consist of two different genotypes. One type is called “emigrants”, having a high reproductive rate and reacting on the stress due to dense populations by dispersal. The other type may be referred to as “tolerants”, being insensitive to overpopulation

H. Dekker

1975-01-01

227

Nutria: An Invasive Rodent Pest or Valued Resource?  

Microsoft Academic Search

Nutria or coypu (Myocastor coypus), semi-aquatic rodents native to southern South America, are an invasive species having detrimental impacts mainly in the southern and eastern United States. Nutria were introduced into the U.S. in 1899 for fur farming and became established in several states. Nutria dispersals resulted primarily from releases by fur farmers, escapes during hurricanes or rising floodwaters, or

SUSAN M. JOJOLA; Gary Witmer; Dale Nolte

2005-01-01

228

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

229

Sexual dimorphism in the white matter of rodents  

Microsoft Academic Search

Sexual dimorphism of astrocytes and neurons is well documented in many brain and spinal cord structures. Sexual dimorphism of oligodendrocytes (Olgs) and myelin has received less attention. We recently showed that density of Olgs in corpus callosum, fornix, and spinal cord of wild-type male rodents is more densely packed than in females; myelin proteins and myelin gene expression are likewise

Mirela Cerghet; Robert P. Skoff; Muthulekha Swamydas; Denise Bessert

2009-01-01

230

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

231

Response of brown treesnakes to reduction of their rodent prey  

USGS Publications Warehouse

Trapping brown treesnakes (Boiga irregularis; BTS) with live-mouse (Mus domesticus) lures is the principal control technique for this invasive species on Guam. Lure-based trapping is also used on other islands as a precaution against undetected arrivals and in response to verified BTS sightings. However, the effectiveness of lure-based trapping on other islands is questionable, as it has yielded no BTS despite other evidence of their presence. Some evidence suggests that high rodent numbers may interfere with BTS control. To test the relationship between rodent abundance and snake trappability, we conducted a controlled, replicated field experiment incorporating a rodenticide treatment during a BTS mark-recapture study. Using open population modeling in Program MARK, we estimated BTS apparent survival and recapture probabilities. Rodent reduction increased BTS recapture probabilities by 52-65% in 2002 and 22-36% in 2003, and it decreased apparent survival by <1% both years. This appears to be the first published instance of manipulating wild prey to influence snake behavior. Rodent reduction may enhance detection and control of BTS with traps on Guam and other islands. It may also amplify the effectiveness of oral toxicants against BTS.

Gragg, J. E.; Rodda, G. H.; Savidge, J. A.; White, G. C.; Dean-Bradley, K.; Ellingson, A. R.

2007-01-01

232

Assessment of the use of selected rodents in ecological monitoring  

NASA Astrophysics Data System (ADS)

Rodents can be useful in detecting environmental impacts because they are easy to study (easy to capture and handle), they can occur in densities adequate for statistical analysis, and they are ecologically important. In this study the usefulness of rodent populations for ecological monitoring was investigated by examining the effect of variation on the possibility of detecting differences among populations of rodents on 10 trapping grids. The effects of sampling frequencies and dispersal on detecting differences in population parameters among grids was also investigated, as was the possibility of inferring population parameters from correlations with habitat data. Statistically significant differences as small as 4.3 Peromyscus maniculatus/ha were detected between grids. Of 10 populations, this comprised 12% of the highest-density population and 44% of the lowest-density population. Smaller and more differences among grids were found by examining only animals surviving from previous months. Dispersal confounds detection of direct impacts to populations, especially during the breeding season. Infrequent sampling fails to detect impacts that occur between sampling periods and will indicate impacts when observed changes result from natural variation. Correlations between population parameters and habitat variables exist but should only be used in predicting, not measuring, impacts. It is concluded that some rodent populations can be used in ecological monitoring. However, intensive sampling is required to account for variation and dispersal.

Douglass, Richard J.

1989-05-01

233

Autopodial skeletal diversity in hystricognath rodents: Functional and phylogenetic aspects  

Microsoft Academic Search

Metapodials and phalanges of the second to fourth digital ray were measured for the hands and feet of 214 specimens belonging to 45 extant species of hystricognath rodents, encompassing members of all major clades of the radiation. Principal components analysis (PCA), the phalangeal index of the third digital ray in the hands and feet, and the relationship between second and

Vera Weisbecker; Simone Schmid

2007-01-01

234

Cultivation of Rodent Typhoid Bacteria on Fish Hydrolysates.  

National Technical Information Service (NTIS)

Media prepared from fish hydrolysates may be used for the cultivation of mother cultures of rodent typhoid bacteria with a content of 90-120 mg % amino nitrogen and 0.4-0.5% sodium chloride in the medium. Upon addition of sodium and potassium salts of pho...

L. V. Malushko

1969-01-01

235

Analysis of environmental sound levels in modern rodent housing rooms  

Microsoft Academic Search

Noise in animal housing facilities is an environmental variable that can affect hearing, behavior and physiology in mice. The authors measured sound levels in two rodent housing rooms (room 1 and room 2) during several 24-h periods. Room 1, which was subject to heavy personnel traffic, contained ventilated racks and static cages that housed large numbers of mice. Room 2

Bradford J. May; Ziwei Judy Hao; Julie Watson; Amanda M. Lauer

2009-01-01

236

The management and breeding of some more hystricomorph rodents  

Microsoft Academic Search

SUMMARY The caging, feeding and handling in our laboratory of 4 unusual hystri- comorph rodents are described. These animals are: the wild guinea-pigs, or cuis (Cavia aperea and Galea musteloides), the degu (Octodon degus), and the plains viscacha (Lagostomus maximus). The species were obtained for investigation of their reproduction and some details of this are given.

Barbara J. Weir

1970-01-01

237

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

238

CONCENTRATED AMBIENT PARTICULATE STUDIES IN HEALTHY AND COMPROMISED RODENTS  

EPA Science Inventory

CONCENTRATED AMBIENT PARTICULATE STUDIES IN HEALTHY AND COMPROMISED RODENTS. WP Watkinson1, LB Wichers2, JP Nolan1, DW Winsett1, UP Kodavanti1, MCJ Schladweiler1, LC Walsh1, ER Lappi1, D Terrell1, R Slade1, AD Ledbetter1, and DL Costa1. 1USEPA, ORD/NHEERL/ETD/PTB, RTP, NC, US...

239

Robust Reproducible Resting State Networks in the Awake Rodent Brain  

PubMed Central

Resting state networks (RSNs) have been studied extensively with functional MRI in humans in health and disease to reflect brain function in the un-stimulated state as well as reveal how the brain is altered with disease. Rodent models of disease have been used comprehensively to understand the biology of the disease as well as in the development of new therapies. RSN reported studies in rodents, however, are few, and most studies are performed with anesthetized rodents that might alter networks and differ from their non-anesthetized state. Acquiring RSN data in the awake rodent avoids the issues of anesthesia effects on brain function. Using high field fMRI we determined RSNs in awake rats using an independent component analysis (ICA) approach, however, ICA analysis can produce a large number of components, some with biological relevance (networks). We further have applied a novel method to determine networks that are robust and reproducible among all the components found with ICA. This analysis indicates that 7 networks are robust and reproducible in the rat and their putative role is discussed.

Becerra, Lino; Pendse, Gautam; Chang, Pei-Ching; Bishop, James; Borsook, David

2011-01-01

240

In vivo rodent micronucleus assay: protocol, conduct and data interpretation  

Microsoft Academic Search

In vivo rodent micronucleus assay has been widely used to detect genotoxicity. Evaluation of micronucleus induction is the primary in vivo test in a battery of genotoxicity tests and is recommended by the regulatory agencies around the globe to be conducted as part of product safety assessment. The assay, when performed appropriately, detects both clastogenicity and aneugenicity. Methods for performing

Gopala Krishna; Makoto Hayashi

2000-01-01

241

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

242

Response of plant and rodent communities to removal of prairie dogs ( Cynomys gunnisoni) in Arizona  

Microsoft Academic Search

We conducted a natural removal experiment, utilizing a local outbreak of sylvatic plague (Yersinia pestis) as the removal agent, to test the effects of removal of Gunnison's prairie dogs (Cynomys gunnisoni) on plant and nocturnal rodent assemblages in three grassland habitats (ponderosa, pinyon-juniper, and desert grasslands) in northern Arizona. We measured plant cover, rodent abundance, plant and rodent species richness,

S. E. Bartz; L. C. Drickamer; M. J. C. Kearsley

2007-01-01

243

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

244

Distribution and ecological observations of wild rodents in Pampa de Achala, Córdoba, Argentina  

Microsoft Academic Search

This study lists the species of rodents living in the Pampa de Achala, a high plain in the Sierras de Córdoba, and analyses their habitat preferences and their Zoogeographic relationships. Five cricetine rodents in order of numbers captured were Akodon sp., Phyllotis darwinii, Oxymycterus paramensis, Reithrodon auritus, and Oligoryzomys flavescens, and one caviomorph rodent, Galea sp. Each of the seven

Jaime J. Polop

1989-01-01

245

HANTAVIRUS(BUNYAVIRIDAE) INFECTIONS IN RODENTS FROM ORANGE AND SAN DIEGO COUNTIES, CALIFORNIA  

Microsoft Academic Search

During a screening program to determine the extent of hantavirus activity in Orange and San Diego Counties, California, serum samples from 2,365 rodents representing nine genera and 15 species were tested for hantavirus antibodies. A reverse transcription-polymerase chain reaction on selected seropositive rodents was used to identify the specific hantavirus. Rodents positive for Sin Nombre virus (SNV) antibodies by Western

STEPHEN G. BENNETT; JAMES P. WEBB; MINOO B. MADON; JAMES E. CHILDS; THOMAS G. KSIAZEK; NORAH TORREZ-MARTINEZ; BRIAN HJELLE

246

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

247

42 CFR 71.56 - African rodents and other animals that may carry the monkeypox virus.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 2010-10-01 false African rodents and other animals that may carry the monkeypox...QUARANTINE Importations § 71.56 African rodents and other animals that may carry the monkeypox...must not import or attempt to import any rodents, whether dead or alive, that...

2010-10-01

248

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.

249

Molecular evolution and phylogenetics of rodent malaria parasites  

PubMed Central

Background Over the last 6 decades, rodent Plasmodium species have become key model systems for understanding the basic biology of malaria parasites. Cell and molecular parasitology have made much progress in identifying genes underpinning interactions between malaria parasites, hosts, and vectors. However, little attention has been paid to the evolutionary genetics of parasites, which provides context for identifying potential therapeutic targets and for understanding the selective forces shaping parasites in natural populations. Additionally, understanding the relationships between species, subspecies, and strains, is necessary to maximize the utility of rodent malaria parasites as medically important infectious disease models, and for investigating the evolution of host-parasite interactions. Results Here, we collected multi-locus sequence data from 58 rodent malaria genotypes distributed throughout 13 subspecies belonging to P. berghei, P. chabaudi, P. vinckei, and P. yoelii. We employ multi-locus methods to infer the subspecies phylogeny, and use population-genetic approaches to elucidate the selective patterns shaping the evolution of these organisms. Our results reveal a time-line for the evolution of rodent Plasmodium and suggest that all the subspecies are independently evolving lineages (i.e. species). We show that estimates of species-level polymorphism are inflated if subspecies are not explicitly recognized, and detect purifying selection at most loci. Conclusions Our work resolves previous inconsistencies in the phylogeny of rodent malaria parasites, provides estimates of important parameters that relate to the parasite’s natural history and provides a much-needed evolutionary context for understanding diverse biological aspects from the cross-reactivity of immune responses to parasite mating patterns.

2012-01-01

250

Tropical cyclone statistics in the Northeastern Pacific  

Microsoft Academic Search

The principal area of tropical cyclogenesis in the tropical eastern Pacific Ocean is offshore in the Gulf of Tehuantepec, between 8 and 15° N, and most of these cyclones move towards the west and northwest during their initial phase. Historical analysis of tropical cyclone data in the Northeastern (NE) Pacific over the last 38 years (from 1966 to 2004) shows

E. ROMERO-VADILLO; O. ZAYTSEV

2007-01-01

251

Tropical Cyclogenesis in the Western North Pacific  

Microsoft Academic Search

Tropical cyclogenesis in the western North Pacific is characterized by an early convective maximum which precedes the initial appearance of a tropical depression. The convection is quantified from cloud areas specified by cold infrared temperature thresholds with 3-hourly GMS satellite data. It is hypothesized that this convective maximum represents an important process associated with tropical cyclogenesis and is a response

Raymond Milton Zehr

1992-01-01

252

Tropical Cyclones, 1987 - Central North Pacific.  

National Technical Information Service (NTIS)

Tropical Storm FERNANDA crossed 140W and into the Central Pacific Hurricane Center's area of responsibility on July 26 at 0000 UTC. FERNANDA developed about 48 hours earlier near 11N 130W as Tropical Depression NINE-E and subsequently attained tropical st...

W. Au A. Chun H. Rosendal

1988-01-01

253

Cyclogenesis and Tropical Transition in Frontal Zones  

Microsoft Academic Search

Tropical cyclones can form from many different precursors, including baroclinic systems. The process of an extratropical system evolving into a warm core tropical cyclone is defined by Davis and Bosart (2004) as a Tropical Transition (TT) with further classification of systems into Weak Extratropical Cylclones (WEC) and Strong Extratropical Cyclones (SEC). It is difficult to predict which systems will make

Michelle L. Stewart

2007-01-01

254

Rethinking Tropical Forest Conservation: Perils in Parks  

Microsoft Academic Search

Abstract. Large, pristine, uninhabited parks are the defining criterion of success in conserving tropical forests, according to someconservationist s. It is argued that human,residents in tropical forests inevitably deplete populations of large animals through hunting, triggering a chain reaction of ecological events that greatly diminish the conservation value ofthese forests. Hence, the removal of people from tropical forests is an

Stephan Schwartzman; Adriana Moreira; Daniel Nepstad

2000-01-01

255

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

256

Stress Responses in Tropical Sparrows: Comparing Tropical and Temperate Zonotrichia  

Microsoft Academic Search

Seasonal modulation of the adrenocortical response appears to be ubiquitous in mid- to high-latitude vertebrates but has not been investigated in tropical vertebrates. Previous studies dem- onstrate that temperate passerines show seasonality in corti- costerone secretion and corticosteroid binding globulin capac- ities. We examined seasonal and sex differences in the stress response in an equatorial population of Zonotrichia capensis, the

Haruka Wada; Ignacio T. Moore; Creagh W. Breuner; John C. Wingfield

2006-01-01

257

Chemical and Radiation Leukemogenesis in Humans and Rodents and the Value of Rodent Models for Assessing Risks of Lymphohematopoietic Cancers.  

National Technical Information Service (NTIS)

This report is intended to provide an up-to-date overview of the lymphoid and hematopietic diseases induced in humans and rodents following exposure to chemical agents. It includes a brief introduction to hematopoiesis and lymphopoiesis in humans and rode...

D. A. Eastmond

1997-01-01

258

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

259

Ecotoxicology of tropical marine ecosystems  

Microsoft Academic Search

The negative effects of chemical contaminants on tropical marine ecosystems are of increasing concern as human populations expand adjacent to these communities. Watershed streams and ground water carry a variety of chemicals from agricultural, industrial, and domestic activities, while winds and currents transport pollutants from atmospheric and oceanic sources to these coastal ecosystems. The implications of the limited information available

Esther C. Peters; Nancy J. Gassman; Julie C. Firman; Robert H. Richmond; Elizabeth A. Power

1997-01-01

260

North Atlantic Tropical Cyclones, 1972.  

National Technical Information Service (NTIS)

There were just four tropical cyclones in 1972 in the North Atlantic--the lowest total in the past 30 yr. Three of those storms reached hurricane intensity. Agnes, of little concern to mariners, became the most destructive storm in U.S. history. There wer...

R. M. DeAngelis

1973-01-01

261

The future of tropical forests.  

PubMed

Five anthropogenic drivers--land use change, wood extraction, hunting, atmospheric change, climate change--will largely determine the future of tropical forests. The geographic scope and intensity of these five drivers are in flux. Contemporary land use change includes deforestation (approximately 64,000 km(2) yr(-1) for the entire tropical forest biome) and natural forests regenerating on abandoned land (approximately 21,500 km(2) yr(-1) with just 29% of the biome evaluated). Commercial logging is shifting rapidly from Southeast Asia to Africa and South America, but local fuelwood consumption continues to constitute 71% of all wood production. Pantropical rates of net deforestation are declining even as secondary and logged forests increasingly replace old-growth forests. Hunters reduce frugivore, granivore and browser abundances in most forests. This alters seed dispersal, seed and seedling survival, and hence the species composition and spatial template of plant regeneration. Tropical governments have responded to these local threats by protecting 7% of all land for the strict conservation of nature--a commitment that is only matched poleward of 40 degrees S and 70 degrees N. Protected status often fails to stop hunters and is impotent against atmospheric and climate change. There are increasing reports of stark changes in the structure and dynamics of protected tropical forests. Four broad classes of mechanisms might contribute to these changes. Predictions are developed to distinguish among these mechanisms. PMID:20536814

Wright, S Joseph

2010-05-01

262

Tropical Biological Drawings with Notes.  

ERIC Educational Resources Information Center

|The annotated illustrations of biological specimens useful for illustrating the "tropical" topics dealt with in African secondary school biology courses are designed to serve a two-fold purpose. The diagrams are intended to show the pupil the structures he should be looking for in his laboratory work, with the textual material being an addition…

Mitchelmore, June A.

263

Digitized Atlantic Tropical Cyclone Tracks.  

National Technical Information Service (NTIS)

A series of 138 maps and diagrams shows both the source regions and eventual disposition of all tropical cyclones passing through unit 2-1/2 degrees latitude-longitude boxes during the 84-year period of record, 1886-1969. Also included are the mean vector...

J. R. Hope C. J. Neumann

1971-01-01

264

Urinogenital infections in the tropics  

Microsoft Academic Search

The range of urinary tract infections and sexually transmitted infections varies from place to place and though the aetiology and clinical presentation of infections is similar in industrialised and developing countries it is evident that persons with these infections resource-constrained tropical areas of the world often present for care with more severe illness and often only after complications have developed.

Ahmed S. Latif

265

The Degeneration of Tropical Geography  

Microsoft Academic Search

How did colonial and tropical geography as practiced in the aftermath of World War II become development geography by the 1970s? We excavate the genealogy of development geography, relating it to geopolitical, economic, and social traumas of decolonization. We examine how revolutionary pressures and insurgencies, coupled with the eclipse of formal colonialism, led to the degeneration and displacement of a

Marcus Power; James D. Sidaway

2004-01-01

266

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

267

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

268

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

269

Rodent control programmes in areas affected by Bolivian haemorrhagic fever.  

PubMed

Bolivian haemorrhagic fever (BHF) caused by Machupo virus is acquired by contact with the excretions and secretions of Calomys callosus, an indigenous cricetine rodent which is preadapted to peridomestic habitats. It competes successfully with Mus musculus, but not with Rattus rattus. A successful disease control programme has functioned in Beni Department since 1964. It is based on trapping surveys and the detection of splenomegaly in Calomys rodents as an index of chronic virus infection. Mass trapping and poisoning are used initially, and regular trapping is employed to control Calomys populations in towns where disease has occurred. More than 1000 cases of BHF were recorded from 1960-1964, but less than 200 in the past 10 years. The cost of this programme is approximately $30 000 annually. PMID:182405

Mercado, R

1975-01-01

270

Primary rodent and lightning protective sheath for lightguide cable  

NASA Astrophysics Data System (ADS)

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 oversheaths. The sheath contains a corrugated stainless steel/copper composite armor layer bonded to an outer polyethylene jacket that contains a layer of wire strength members. The design is compact, rugged and flexible and is as small as an unarmored crossply sheath and only slightly heavier. This new sheath is suitable for a variety of fiber core constructions and outside plant applications. The design effort included investigations of rodent deterrence, lightning protection, mechanical performance, and optical transmission performance. Test results and product applications are discussed.

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

1986-11-01

271

Of mice and women: rodent models of placental malaria.  

PubMed

Pregnant women are at increased malaria risk. The infections are characterized by placental accumulation of infected erythrocytes (IEs) with adverse consequences for mother and baby. Placental IE sequestration in the intervillous space is mediated by variant surface antigens (VSAs) selectively expressed in placental malaria (PM) and specific for chondroitin sulfate A (CSA). In Plasmodium falciparum, these VSA(PM) appear largely synonymous with the P. falciparum erythrocyte membrane protein 1 (PfEMP1) family variant VAR2CSA. As rodent malaria parasites do not possess PfEMP1 homologs, the usefulness of experimental mouse PM models remains controversial. However, many features of murine and human PM are similar, including involvement of VSAs analogous to PfEMP1. It thus appears that rodent model studies can further the understanding of VSA-dependent malaria pathogenesis and immunity. PMID:20605743

Hviid, Lars; Marinho, Claudio R F; Staalsoe, Trine; Penha-Gonçalves, Carlos

2010-05-31

272

Using rodents to model schizophrenia and substance use comorbidity.  

PubMed

Schizophrenia and substance use disorders (SUD) often occur together, yet it is unclear why this is the case or how best to manage dual diagnosis. Rodent models are well suited to study how genes and environment interact to impact neurodevelopment, brain function and behaviors relevant to dual diagnosis. Indeed a variety of rodent models for schizophrenia display behavioral and physiological features relevant to SUD including: neurodevelopmental models, models of a rare variant (Disc1), to models of common variants (neurexin, dysbindin and neuregulin), and models of various gene-drug interactions. Thus it may be worthwhile to probe models of schizophrenia for insights relevant to SUD and dual diagnosis. However, future studies on dual diagnosis should involve characterization beyond measuring locomotor responses to self-administration tasks, include drug classes other than psychostimulants, and dissect the neuroadaptations that underlie risk for dual diagnosis. PMID:23567519

Ng, Enoch; McGirr, Alexander; Wong, Albert H C; Roder, John C

2013-04-06

273

First diatomyid rodent from the Early Miocene of Arabia  

NASA Astrophysics Data System (ADS)

The Asian family Diatomyidae is known from the Early Oligocene to the present. Among living rodents, this group comprises only the recently discovered Laonastes aenigmamus from Laos. Fossil diatomyids are known from only a few sites, in which they are often rare. The discovery of Pierremus explorator gen. nov. sp. nov. in the Lower Miocene of As-Sarrar (Saudi Arabia) raises to ten the number of extinct diatomyid species recognized. Pierremus explorator is the first record of a diatomyid from the Afro-Arabian plate. This discovery provides evidence that, together with other rodents (ctenodactylids, zapodids…), the diatomyids took advantage of the corridor that was established between Afro-Arabia and Eurasia in Early Miocene times.

López-Antoñanzas, Raquel

2011-02-01

274

First diatomyid rodent from the Early Miocene of Arabia  

NASA Astrophysics Data System (ADS)

The Asian family Diatomyidae is known from the Early Oligocene to the present. Among living rodents, this group comprises only the recently discovered Laonastes aenigmamus from Laos. Fossil diatomyids are known from only a few sites, in which they are often rare. The discovery of Pierremus explorator gen. nov. sp. nov. in the Lower Miocene of As-Sarrar (Saudi Arabia) raises to ten the number of extinct diatomyid species recognized. Pierremus explorator is the first record of a diatomyid from the Afro-Arabian plate. This discovery provides evidence that, together with other rodents (ctenodactylids, zapodids…), the diatomyids took advantage of the corridor that was established between Afro-Arabia and Eurasia in Early Miocene times.

López-Antoñanzas, Raquel

2010-12-01

275

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

276

Eighth complementation group of rodent cells hypersensitive to ultraviolet radiation  

SciTech Connect

Two mutant lines (US31, US46) of mouse lymphoma cells that are hypersensitive to ultraviolet (UV) radiation were previously found to belong to different complementation groups. The mutants were tested for their ability to complement the six known complementation groups of UV-sensitive Chinese hamster ovary (CHO) cells, which are defective in nucleotide excision repair, as well as a seventh group represented by a V79 mutant. Hybrid cells were produced by fusion with polyethylene glycol and tested in situ for UV resistance. The mouse mutant US46 complemented all CHO mutants except UV61. Therefore, US46 is assigned to the same complementation group as UV61, and it is probably defective in the same locus. The mouse mutant US31 produced UV-resistant hybrid cells in each of the seven crosses, indicating that it forms an eighth complementation group among the rodent mutants. Thus, at least eight genes are likely required to repair UV damage in rodent cells.

Thompson, L.H.; Shiomi, T.; Salazar, E.P.; Stewart, S.A.

1988-11-01

277

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

278

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

279

Defensive burying in rodents: ethology, neurobiology and psychopharmacology  

Microsoft Academic Search

Defensive burying refers to the typical rodent behavior of displacing bedding material with vigorous treading-like movements of their forepaws and shoveling movements of their heads directed towards a variety of noxious stimuli that pose a near and immediate threat, such as a wall-mounted electrified shock-prod. Since its introduction 25 years ago by Pinel and Treit [J. Comp. Physiol. Psychol. 92

Sietse F. De Boer; Jaap M. Koolhaas

2003-01-01

280

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

281

Induction of Covalent DNA Adducts in Rodents by Tamoxifen  

Microsoft Academic Search

The antiestrogen tamoxifen, increasingly used as adjuvant treatment for breast cancer, has been found to covalently modify DNA of rodents. For instance, the liver DNA of female Sprague-Dawley rats treated with a single injection of tamoxifen contained two DNA adducts. Four addi tional DNA adducts were formed and adduct concentrations increased 5- 7- and 10-15-fold after three and six tamoxifen

Xueliang Han

282

Rodent seed predation and seedling recruitment in mesic grassland  

Microsoft Academic Search

Seedling recruitment of two grasses (Arrhenatherum elatius and Festuca rubra) and two herbs (Centaurea nigra and Rumex acetosa) was measured in areas with and without rodents to which seeds of each species were sown at three seed densities (1000, 10,000\\u000a and 50,000 seeds m?2) in two seasons (spring and autumn 1995). Seed removal was measured for 10-day periods and the

G. R. Edwards; M. J. Crawley

1999-01-01

283

The Complexity of Alcohol Drinking: Studies in Rodent Genetic Models  

Microsoft Academic Search

Risk for alcohol dependence in humans has substantial genetic contributions. Successful rodent models generally attempt to\\u000a address only selected features of the human diagnosis. Most such models target the phenotype of oral administration of alcohol\\u000a solutions, usually consumption of or preference for an alcohol solution versus water. Data from rats and mice for more than\\u000a 50 years have shown genetic influences

John C. CrabbeTamara; Tamara J. Phillips; John K. Belknap

2010-01-01

284

Transgenesis Via Intracytoplasmic Sperm Injection (ICSI) in Rodents  

Microsoft Academic Search

Intracytoplasmic sperm injection (ICSI) has been successfully achieved in mice and rats using a piezo-driven injection pipette. More than 30% of ICSI oocytes are capable of developing to full-term when the isolated sperm heads are microinjected. The ICSI technique has been applied not only to rescue infertile male strains, but also to produce transgenic rodents. ICSI-mediated DNA transfer, which mixes

Masumi Hirabayashi; Megumi Kato; Shinichi Hochi

2006-01-01

285

Developmental learning impairments in a rodent model of nodular heterotopia  

Microsoft Academic Search

Developmental malformations of neocortex—including microgyria, ectopias, and periventricular nodular heterotopia (PNH)—have\\u000a been associated with language learning impairments in humans. Studies also show that developmental language impairments are\\u000a frequently associated with deficits in processing rapid acoustic stimuli, and rodent models have linked cortical developmental\\u000a disruption (microgyria, ectopia) with rapid auditory processing deficits. We sought to extend this neurodevelopmental model\\u000a to evaluate

Steven W. Threlkeld; Courtney A. Hill; Caitlin E. Cleary; Dongnhu T. Truong; Glenn D. Rosen; R. Holly Fitch

2009-01-01

286

Yin Yang 1 Expression in the Adult Rodent Brain  

Microsoft Academic Search

Yin Yang 1 (YY1) is a ubiquitous transcription factor belonging to Polycomb group proteins. Its expression patterns in the\\u000a adult brain have not been before clearly elucidated. Using immunohistochemical stainings, we show a distribution of YY1 protein\\u000a throughout the adult rodent brain. Furthermore, we characterize a cellular localization of YY1 protein and mRNA in the adult\\u000a rat hippocampus. We have

Marcin Rylski; Renata Amborska; Katarzyna Zybura; Filip A. Konopacki; Grzegorz M. Wilczynski; Leszek Kaczmarek

2008-01-01

287

Expression of Functional Leptin Receptors in Rodent Leydig Cells  

Microsoft Academic Search

Several studies indicate that the size of body fat stores and the circulating levels of the adipocyte-derived hormone leptin are able to influence the activity of the hypothalamic-pituitary-gonadal axis. The leptin-hypothalamic-pituitary-gonadal interactions have been mainly studied at the level of the central nervous system. In this study, we investigated the possibility that leptin may have direct effects on the rodent

MASSIMILIANO CAPRIO; ANDREA M. ISIDORI; ANNA R. CARTA; COSTANZO MORETTI; MARIA L. DUFAU; ANDREA FABBRI

1999-01-01

288

[Rodent thyroid gland function under hot climatic conditions].  

PubMed

Studies have been made on the effect of high temperature and intensive insolation upon the uptake of iodide and hormone formation in the thyroid of rodents (Rhombomys opimus, Spermophilopsis leptodactylus, Citellus fulvus) with different adaptation to the environment. It was shown that high temperature in combination with solar radiation significantly decreases functional activity of the thyroid and affects some of the physiological indices of the organism. Animals with different ecological specialization differ in their reaction to factors of the hot climate. PMID:899379

Akhmetov, I Z; Turakulov, Ia Kh; Kha?rutdinov, Kh Sh

289

New rodent models for studies of chemopreventive agents.  

PubMed

Some recent studies of the effects of chemopreventive agents have begun to use new rodent models to improve the analysis of stages of colonic preneoplasia, and how chemopreventive agents modify progressive abnormal cell development. In one of the models of inherited predisposition to colon cancer, mice carrying a truncated Apc allele with a nonsense mutation in exon 15 have been generated by gene targeting and embryonic stem cell technology (Apc1638 mice). These mice develop multiple gastrointestinal lesions, including adenomas and carcinomas, focal areas of high-grade dysplasia (FAD), and polypoid hyperplasias with FADS. The incidence of inherited colonic neoplasms has now been modulated by a chemopreventive regimen. Colonic lesions significantly increased in Apc1638 mice on a Western-style diet, which has higher fat content and lower calcium and vitamin D compared to the same mice on AIN-76A diet. In another rodent model, Min mice were treated with sulindac, which markedly reduced the incidence of intestinal tumors. A third new rodent model containing a targeted mutation in the gene Mcc (mutated in colorectal cancer) recently became available for chemoprevention studies. These mice develop multiple types of neoplasms including adenocarcinomas, focal areas of gastrointestinal dysplasia, papillomas of the forestomach, and tumors in other organs including lung, liver, and lymphoid tissue. Feeding a Western-style diet to the Mcc mutant mice also resulted in significantly increased gastrointestinal lesions. These nutrient modifications also have been given to normal mice, demonstrating without any chemical carcinogen that a Western-style diet induced colonic tumorigenesis. Western-style diets also have now induced modulation of cell proliferation in other organs including mammary gland, pancreas, and prostate. These findings help develop new preclinical rodent models to aid the analysis of genetic and environmental factors leading to neoplasia, as well as new methods for evaluating the chemopreventive efficacy of specific nutrients and pharmacological agents. PMID:9589360

Lipkin, M

1997-01-01

290

Tenacious nipple attachment in rodents: the sibling competition hypothesis  

Microsoft Academic Search

Tenacious attachment to the mother's nipples by suckling pups has been observed in many rodent species, but apeears to be absent in others. The natural history of this behaviour is reviewed, along with the possible adaptive value. Four hypotheses are extracted from the literature: the antipredator, anti-falling, anti-drowning, and infant-nipple contact hypotheses. These hypotheses are found to be ad hoc

Avery N. Gilbert

1995-01-01

291

Ungulates, rodents, shrubs: interactions in a diverse Mediterranean ecosystem  

Microsoft Academic Search

Ungulate abundance has increased dramatically worldwide, having strong impacts on ecosystem functioning. High ungulate densities can reduce the abundance, diversity and\\/or body condition of small mammals, which has been attributed to reductions in cover shelter and food availability by ungulates. The densities of wild ungulates have increased recently in high-diversity Mediterranean oak ecosystems, where acorn-dispersing small rodents are keystone species.

Alberto Muñoz; Raúl Bonal; Mario Díaz

2009-01-01

292

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

293

Accelerative forces associated with routine inhouse transportation of rodent cages.  

PubMed

Transportation of rodents has repeatedly been demonstrated to potentially affect research outcomes. In addition, rapid acceleration and deceleration have marked physiologic effects. The current study determined the accelerative forces associated with common types of animal transportation within the institution and means of reducing these effects. A rodent-sized (24 g) accelerometer was placed in a standard polycarbonate mouse cage, which then was hand-carried or loaded onto a plastic, small metal, or large metal cart. The cage then moved along a set path that included several flooring types and obstacles. Accelerative forces within the mouse cage varied by as much as 35 m/s(2) in as little as 1 s, primarily along the vertical axis (Z-axis). Measured acceleration was greatest with the plastic cart and lowest during hand-carrying. The placement of a towel under the cage dampened in-cage acceleration due to cart use by more than 50%, whereas a similarly located underpad had no significant effect. These data document that small rodents typically are exposed to considerable motion during transportation. The resulting physical and physiologic effects could affect study outcomes. PMID:23312081

Hurst, Keriann; Litwak, Kenneth N

2012-01-01

294

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

295

Selectively bred rodents as models of depression and anxiety.  

PubMed

Stress related diseases such as depression and anxiety have a high degree of co morbidity, and represent one of the greatest therapeutic challenges for the twenty-first century. The present chapter will summarize existing rodent models for research in psychiatry, mimicking depression- and anxiety-related diseases. In particular we will highlight the use of selective breeding of rodents for extremes in stress-related behavior. We will summarize major behavioral, neuroendocrine and neuronal parameters, and pharmacological interventions, assessed in great detail in two rat model systems: The Flinders Sensitive and Flinders Resistant Line rats (FSL/FRL model), and rats selectively bred for high (HAB) or low (LAB) anxiety related behavior (HAB/LAB model). Selectively bred rodents also provide an excellent tool in order to study gene and environment interactions. Although it is generally accepted that genes and environmental factors determine the etiology of mental disorders, precise information is limited: How rigid is the genetic disposition? How do genetic, prenatal and postnatal influences interact to shape adult disease? Does the genetic predisposition determine the vulnerability to prenatal and postnatal or adult stressors? In combination with modern neurobiological methods, these models are important to elucidate the etiology and pathophysiology of anxiety and affective disorders, and to assist in the development of new treatment paradigms. PMID:22351423

Wegener, Gregers; Mathe, Aleksander A; Neumann, Inga D

2012-01-01

296

Sexual dimorphism in the white matter of rodents  

PubMed Central

Sexual dimorphism of astrocytes and neurons is well documented in many brain and spinal cord structures. Sexual dimorphism of oligodendrocytes (Olgs) and myelin has received less attention. We recently showed that density of Olgs in corpus callosum, fornix, and spinal cord of wild-type male rodents are more densely packed than in females; myelin proteins and myelin gene expression is likewise greater in males than in female rodents. However, glial cell proliferation and cell death were two times greater in female corpus callosum. Endogenous sex hormones, specifically lack of androgens, produce an Olg female phenotype in castrated male mouse. In vitro studies using Olgs culture also showed differences between males and females Olg survival and signaling pathways in response to sexual hormones. Sexual dimorphism of white matter tracts and glia in rodents indicates the necessity for controlling gender in experimental studies of neurodegenerative disorders. Most importantly, our studies suggest that hormones may contribute to sexual dimorphism observed in certain human diseases including multiple sclerosis.

Cerghet, Mirela; Skoff, Robert P.; Swamydas, Muthulekha; Bessert, Denise

2009-01-01

297

Isolating human DNA repair genes using rodent-cell mutants  

SciTech Connect

The DNA repair systems of rodent and human cells appear to be at least as complex genetically as those in lower eukaryotes and bacteria. The use of mutant lines of rodent cells as a means of identifying human repair genes by functional complementation offers a new approach toward studying the role of repair in mutagenesis and carcinogenesis. In each of six cases examined using hybrid cells, specific human chromosomes have been identified that correct CHO cell mutations affecting repair of damage from uv or ionizing radiations. This finding suggests that both the repair genes and proteins may be virtually interchangeable between rodent and human cells. Using cosmid vectors, human repair genes that map to chromosome 19 have cloned as functional sequences: ERCC2 and XRCC1. ERCC1 was found to have homology with the yeast excision repair gene RAD10. Transformants of repair-deficient cell lines carrying the corresponding human gene show efficient correction of repair capacity by all criteria examined. 39 refs., 1 fig., 1 tab.

Thompson, L.H.; Weber, C.A.; Brookman, K.W.; Salazar, E.P.; Stewart, S.A.; Mitchell, D.L.

1987-03-23

298

Quantification of Adiposity in Small Rodents using Micro-CT  

PubMed Central

Non-invasive three-dimensional imaging of live rodents is a powerful research tool that has become critical for advances in many biomedical fields. For investigations into adipose development, obesity, or diabetes, accurate and precise techniques that quantify adiposity in vivo are critical. Because total body fat mass does not accurately predict health risks associated with the metabolic syndrome, imaging modalities should be able to stratify total adiposity into subcutaneous and visceral adiposity. Micro-computed tomography (micro-CT) acquires high-resolution images based on the physical density of the material and can readily discriminate between subcutaneous and visceral fat. Here, a micro-CT based method to image the adiposity of live rodents is described. An automated and validated algorithm to quantify the volume of discrete fat deposits from the computed tomography is available. Data indicate that scanning the abdomen provides sufficient information to estimate total body fat. Very high correlations between micro-CT determined adipose volumes and the weight of explanted fat pads demonstrate that micro-CT can accurately monitor site-specific changes in adiposity. Taken together, in vivo micro-CT is a non-invasive, highly quantitative imaging modality with greater resolution and selectivity, but potentially lower through-put, than many other methods to precisely determine total and regional adipose volumes and fat infiltration in live rodents.

Judex, S.; Luu, Y.K.; Ozcivici, E.; Adler, B.; Lublinsky, S.; Rubin, C.T.

2009-01-01

299

Breath-hold device for laboratory rodents undergoing imaging procedures.  

PubMed

The increased use in noninvasive imaging of laboratory rodents has prompted innovative techniques in animal handling. Lung imaging of rodents can be a difficult task because of tissue motion caused by breathing, which affects image quality. The use of a prototype flat-panel computed tomography unit allows the acquisition of images in as little as 2, 4, or 8 s. This short acquisition time has allowed us to improve the image quality of this instrument by performing a breath-hold during image acquisition. We designed an inexpensive and safe method for performing a constant-pressure breath-hold in intubated rodents. Initially a prototypic manual 3-way valve system, consisting of a 3-way valve, an air pressure regulator, and a manometer, was used to manually toggle between the ventilator and the constant-pressure breath-hold equipment. The success of the manual 3-way valve system prompted the design of an electronically actuated valve system. In the electronic system, the manual 3-way valve was replaced with a custom designed 3-way valve operated by an electrical solenoid. The electrical solenoid is triggered by using a hand-held push button or a foot pedal that is several feet away from the gantry of the scanner. This system has provided improved image quality and is safe for the animals, easy to use, and reliable. PMID:16884181

Rivera, Belinda; Bushman, Mark J; Beaver, Richard G; Cody, Dianna D; Price, Roger E

2006-07-01

300

Rodent Damage to Natural and Replanted Mountain Forest Regeneration  

PubMed Central

Impact of small rodents on mountain forest regeneration was studied in National Nature Reserve in the Beskydy Mountains (Czech Republic). A considerable amount of bark damage was found on young trees (20%) in spring after the peak abundance of field voles (Microtus agrestis) in combination with long winter with heavy snowfall. In contrast, little damage to young trees was noted under high densities of bank voles (Myodes glareolus) with a lower snow cover the following winter. The bark of deciduous trees was more attractive to voles (22% damaged) than conifers (8%). Young trees growing in open and grassy localities suffered more damage from voles than those under canopy of forest stands (?2 = 44.04, P < 0.001). Natural regeneration in Nature Reserve was less damaged compared to planted trees (?2 = 55.89, P < 0.001). The main factors influencing the impact of rodent species on tree regeneration were open, grassy habitat conditions, higher abundance of vole species, tree species preferences- and snow-cover condition. Under these conditions, the impact of rodents on forest regeneration can be predicted. Foresters should prefer natural regeneration to the artificial plantings.

Heroldova, Marta; Bryja, Josef; Janova, Eva; Suchomel, Josef; Homolka, Miloslav

2012-01-01

301

Rodent models of binge eating: are they models of addiction?  

PubMed

Are recently developed rodent models of binge eating also models of food addiction? Valid models should meet human criteria for both bingeing and substance dependence as described in the 4th edition and proposed for the 5th edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM). Similarly, behavioral profiles of bingeing animals should share characteristics with those of animal models of drug addiction. We evaluate and discuss current rodent models of bingeing, their contributions to scientific understanding of bingeing, their validity with respect to DSM criteria, and their overlap with models of addiction. The models described indicate that repeated intermittent bouts in which large quantities of fatty or sugary foods are consumed (binges) are associated with behavioral changes similar to those described for drugs of abuse. In contrast, control groups consuming the same foods in a nonbinge-type manner do not exhibit an "addiction-like" behavioral profile. Thus, fatty/sugary foods in and of themselves do not appear to have addictive qualities. Rather, the manner in which they are consumed appears to be critical. In addition, while rodent models of bingeing and drug self-administration share similarities, we do not support reclassifying the bingeing-related eating disorders as substance use disorders because of differences that distinguish such disorders in humans. PMID:23520597

Corwin, Rebecca L W; Babbs, R Keith

2012-01-01

302

Accelerative Forces Associated with Routine Inhouse Transportation of Rodent Cages  

PubMed Central

Transportation of rodents has repeatedly been demonstrated to potentially affect research outcomes. In addition, rapid acceleration and deceleration have marked physiologic effects. The current study determined the accelerative forces associated with common types of animal transportation within the institution and means of reducing these effects. A rodent-sized (24 g) accelerometer was placed in a standard polycarbonate mouse cage, which then was hand-carried or loaded onto a plastic, small metal, or large metal cart. The cage then moved along a set path that included several flooring types and obstacles. Accelerative forces within the mouse cage varied by as much as 35 m/s2 in as little as 1 s, primarily along the vertical axis (Z-axis). Measured acceleration was greatest with the plastic cart and lowest during hand-carrying. The placement of a towel under the cage dampened in-cage acceleration due to cart use by more than 50%, whereas a similarly located underpad had no significant effect. These data document that small rodents typically are exposed to considerable motion during transportation. The resulting physical and physiologic effects could affect study outcomes.

Hurst, Keriann; Litwak, Kenneth N

2012-01-01

303

Evidence for rodent-common and species-typical limb and digit use in eating, derived from a comparative analysis of ten rodent species  

Microsoft Academic Search

Order Rodentia comprises a vast portion of mammalian species (1814 species), which occupy extremely diverse habitats requiring very distinct motor specializations (e.g. burrowing, hopping, climbing, flying and swimming). Although early classification of paw use ability suggests rodents are impoverished relative to primates and make little use of their paws, there have been no systematic investigations of paw use in rodents.

I. Q. Whishaw; J. R. Sarna; S. M. Pellis

1998-01-01

304

Results from a Survey of Current Practices for Sampling of Nervous System in Rodents and Non-rodents in General Toxicity Studies  

EPA Science Inventory

A survey of current practices for sampling and examination of the nervous system in rodents and non-rodents for general and neurotoxicity (NT) studies was conducted by the Nervous System Sampling Subcommittee of the STP. For general toxicity studies most of those surveyed (>63%) ...

305

Stress responses in tropical sparrows: comparing tropical and temperate Zonotrichia.  

PubMed

Seasonal modulation of the adrenocortical response appears to be ubiquitous in mid- to high-latitude vertebrates but has not been investigated in tropical vertebrates. Previous studies demonstrate that temperate passerines show seasonality in corticosterone secretion and corticosteroid binding globulin capacities. We examined seasonal and sex differences in the stress response in an equatorial population of Zonotrichia capensis, the only Zonotrichia that breeds in the tropics, and compared the results with those of northern Zonotrichia. Seasonal differences in tropical Zonotrichia would presumably be independent of photoperiod and thus directly related to such activities as reproduction and feather molt. In addition, we investigated the possible role of binding globulin as a sex steroid binding globulin, as suggested for temperate passerines. Similar to northern congeners, Z. capensis show seasonal modulation in total corticosterone and binding globulin capacity with higher levels during breeding than molt. However, unlike many temperate passerines, there are no sex differences in corticosterone secretion or binding globulin capacity. Furthermore, the seasonal differences in total corticosterone diminish when the free levels are calculated. The contrast between equatorial and northern congeners indicates factors such as breeding environment and life-history strategy may play important roles in shaping stress response in these species. PMID:16826504

Wada, Haruka; Moore, Ignacio T; Breuner, Creagh W; Wingfield, John C

2006-06-19

306

Relationship between Tropical Atlantic sea surface temperature variability and southern Indian Ocean tropical cyclones  

NASA Astrophysics Data System (ADS)

Recent studies have found that tropical Atlantic sea surface temperature (SST) variability may be influencing tropical Indian Ocean climate. Due to the economic and social impact of tropical cyclones, it is important to investigate how an Atlantic-Indian Ocean connection may be affecting tropical cyclone behavior in the southern Indian Ocean. In this study, the International Best Track Archive for Climate Stewardship (IBTrAC) tropical cyclone database is used to derive metrics of tropical cyclone behavior, which are then compared with an index of tropical Atlantic SST variability. Changes in tropical Atlantic SSTs are found to coincide with significant differences in tropical cyclone activity for portions of the southern Indian Ocean. In addition, for these same regions, tropical Atlantic SST variability is associated with changes in large-scale atmospheric conditions, including wind shear, low-level vorticity, and humidity, typically associated with tropical cyclogenesis. These findings indicate a possible link between tropical Atlantic conditions and cyclone activity in the Indian Ocean mediated through a teleconnection between tropical Atlantic SSTs and large scale atmospheric conditions over the southern Indian Ocean. The nature of this teleconnection and the mechanisms driving it are being further explored with model experiments.

DeBlander, E.; Shaman, J. L.

2011-12-01

307

Smithsonian Tropical Research Institute: Bibliography  

NSDL National Science Digital Library

The Smithsonian Tropical Research Institute (STRI) is located in Panama (first reported on in the March 26, 2004, Scout Report), and hosts hundreds of "visiting scientists from academic and research institutions in the United States and around the world every year." The STRI Bibliography "cites publications by the staff, visitors, fellows and students that result from research supported by the Smithsonian Tropical Research Institute." The Bibliography contains thousands of references to theses, books, and articles ranging from 1911-2004. Scientists who are interested in conducting research at STRI can link from the Bibliography to the Research Applications section for an application form and information about scientific permits, fees, visiting Panama, and underwater diving.

308

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

309

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 areas along the top of the clouds indicate cloud ice, while the wavy blue lines on the bottom indicate intense rainfall. Credit: NASA/JPL/Colo. State Univ./NRL-Monterey

Karl Hille

2012-08-29

310

Health crusades and tropical diseases.  

PubMed

Worldwide attempts to eradicate yaws, malaria, and smallpox have all been effective to varying extents, and all have taught some valuable lessons that should be taken into account as a new global crusade is mounted against tropical diseases. But it should not be forgotten that infectious disease remains a major public health problem in the U.S., and new diseases are arising to replace those already vanquished. PMID:7399467

Weller, T H

1980-03-01

311

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

312

Flavonoids in tropical citrus species.  

PubMed

HPLC with PDA and MS(2) detection was used to identify and quantify flavonoids in the tropical citrus species Citrus microcarpa , Citrus hystrix , Citrus medica var. 1 and 2, and Citrus suhuiensis . Most of these species contained high amounts of flavones, flavanones, and dihydrochalcone C- and/or O-glycosides, which were identified on the basis of HPLC retention times, cochromatography with available authentic standards, absorbance spectra, and mass spectral fragmentation patterns. Among the major compounds detected were apigenin-6,8-di-C-glucoside, apigenin-8-C-glucosyl-2?-O-rhamnoside, phloretin-3',5'-di-C-glucoside, diosmetin-7-O-rutinoside, hesperetin-7-O-neohesperidoside, and hesperetin-7-O-rutinoside. Most of the dihydrochalcone and flavone C-glycosides have not previously been detected in tropical citrus. C. microcarpa contained a high amount of phloretin-3',5'-di-C-glucoside. Most of the tropical citrus flavanones were neohesperidoside conjugates, which are responsible for imparting a bitter taste to the fruit. Only C. suhuiensis fruit contains rutinoside, a nonbitter conjugate. PMID:21978223

Roowi, Suri; Crozier, Alan

2011-10-19

313

Sustainable simulated commodity tropical hardwood panel  

US Patent & Trademark Office Database

A simulated commodity tropical hardwood-based panel includes an engineered veneer face including a first wood from one or more sustainable sources of wood. The face has a dyed coloring, a simulated grain, or a dyed coloring and a simulated grain that is substantially similar to the coloring, grain, or coloring and grain of a tropical hardwood veneer. The panel further includes a back and a core disposed between the face and back. The face, the core and back are stacked and adhered together to form a laminated panel. The face of the simulated commodity tropical hardwood-based panel has an appearance that is substantially similar to the appearance of the face veneer of a commodity tropical hardwood-based panel that includes the tropical hardwood veneer. The panel comprises no tropical hardwood from a non-sustainable source of wood.

2013-04-09

314

A Student Guide to Tropical Forest Conservation  

NSDL National Science Digital Library

This student guide provides an introduction to the types and value of tropical forests, deforestation, the practice of forestry, forestry research, and tropical forestry. The guide shows how modern practices can help stem the tide of forest destruction while continuing to provide valuable products for people. Examples of sustainable forestry are cited, which could be used as models for protecting and managing tropical forests worldwide.

315

THE GLOBAL TROPICAL MOORED BUOY ARRAY  

Microsoft Academic Search

This paper describes the Global Tropical Moored Buoy Array (GTMBA), which is a multi-national effort to provide data in real time for climate research and forecasting. Components of the global array include the Tropical Atmosphere Ocean\\/Triangle Trans-Ocean Buoy Network (TAO\\/TRITON) in the Pacific, the Prediction and Research Moored Array in the Tropical Atlantic (PIRATA), and the Research Moored Array for

M. Ravichandran; J. Vialard; D. Vousden

316

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

317

Diagnostic research into the tropical atmosphere and the role of tropical processes in the general circulation  

NASA Astrophysics Data System (ADS)

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 the oceans, and mesoscale depressions in the Inter-Tropical Convergence Zone is discussed. Use of FGGE data is described.

Petrossiants, M. A.; Sitnikov, I. G.

1986-04-01

318

A TROPICAL GARDEN FLORA, PLANTS CULTIVATED IN THE HAWAIIAN ISLANDS AND OTHER TROPICAL AREAS.  

Technology Transfer Automated Retrieval System (TEKTRAN)

Pemberton, R.W. A Tropical Garden Flora, Plants Cultivated in the Hawaiian Islands and Other Tropical Areas. Economic Botany This is an invited book review of an important new reference book on plants cultivated in the tropical and subtropical areas of the world. This is the long awaited update of ...

319

Correlation Between Tropical Convection and Upper Tropospheric Momentum Flux Convergence.  

National Technical Information Service (NTIS)

In this article, the focus is on the relationship between tropical convection and the convergence of eastward momentum. This relationship is investigated using global data sets related to both tropical convection and momentum convergence. Tropical convect...

M. T. Boehm D. O. C. Starr

2003-01-01

320

Serological study of hantavirus in the rodent population of Nakhon Pathom and Nakhon Ratchasima Provinces Thailand.  

PubMed

A serological survey has been carried out to detect evidence of hantavirus infection in rodents from two provinces of Thailand. This study aimed to examine virus antibody in 354 rodents trapped among 6 different villages of Nakhon Pathom Province (February-March, 1998) and in 326 rodents trapped among 14 villages of Nakhon Ratchasima Province (August-October, 1998). Seroprevalence among rodents from Nakhon Pathom Province (2.3%), was mostly find in Rattus norvegicus (3.8%) and Bandicota indica (2.6%). In Nakhon Ratchasima Province seroprevalence (4.0%) was mostly in Bandicota indica (19.1%) and Rattus exulans (3.5%). PMID:11127326

Nitatpattana, N; Chauvancy, G; Dardaine, J; Poblap, T; Jumronsawat, K; Tangkanakul, W; Poonsuksombat, D; Yoksan, S; Gonzalez, J P

2000-06-01

321

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

322

[11C]Rhodamine-123: synthesis and biodistribution in rodents  

PubMed Central

Introduction Rhodamine-123 is a known substrate for the efflux transporter, P-glycoprotein (P-gp). We wished to assess whether rhodamine-123 might serve as a useful substrate for developing probes for imaging efflux transporters in vivo with positron emission tomography (PET). For this purpose, we aimed to label rhodamine-123 with carbon-11 (t1/2 = 20.4 min) and to study its biodistribution in rodents. Methods [11C]Rhodamine-123 was prepared by treating rhodamine-110 (desmethyl-rhodamine-123), with [11C]methyl iodide. The biodistribution of this radiotracer was studied with PET in wild-type mice and rats, in efflux transporter knockout mice, in wild-type rats pretreated with DCPQ (an inhibitor of P-gp) or with cimetidine (an inhibitor of organic cation transporters; OCT), and in P-gp knockout mice pretreated with cimetidine. Unchanged radiotracer in forebrain, plasma and peripheral tissues was also measured ex vivo at 30 min after radiotracer administration to wild-type and efflux transporter knockout rodents. Results [11C]Rhodamine-123 was obtained in 4.4% decay-corrected radiochemical yield from cyclotron-produced [11C]carbon dioxide. After intravenous administration of [11C]rhodamine-123 to wild-type rodents, PET and ex vivo measurements showed radioactivity uptake was very low in brain, but relatively high in some other organs such as heart, and especially liver and kidney. Inhibition of P-gp increased uptake in brain, heart, kidney and liver, but only by up to twofold. Secretion of radioactivity from kidney was markedly reduced by OCT knockout or pretreatment with cimetidine. Conclusions [11C]Rhodamine-123 was unpromising as a PET probe for P-gp function and appears to be a strong substrate of OCT in kidney. Cimetidine appears effective for blocking OCT in kidney in vivo.

Bao, Xiaofeng; Lu, Shuiyu; Liow, Jeih-San; Morse, Cheryl L.; Anderson, Kacey; Zoghbi, Sami S.; Innis, Robert B.; Pike, Victor W.

2012-01-01

323

Default-Mode-Like Network Activation in Awake Rodents  

PubMed Central

During wakefulness and in absence of performing tasks or sensory processing, the default-mode network (DMN), an intrinsic central nervous system (CNS) network, is in an active state. Non-human primate and human CNS imaging studies have identified the DMN in these two species. Clinical imaging studies have shown that the pattern of activity within the DMN is often modulated in various disease states (e.g., Alzheimer's, schizophrenia or chronic pain). However, whether the DMN exists in awake rodents has not been characterized. The current data provides evidence that awake rodents also possess ‘DMN-like’ functional connectivity, but only subsequent to habituation to what is initially a novel magnetic resonance imaging (MRI) environment as well as physical restraint. Specifically, the habituation process spanned across four separate scanning sessions (Day 2, 4, 6 and 8). At Day 8, significant (p<0.05) functional connectivity was observed amongst structures such as the anterior cingulate (seed region), retrosplenial, parietal, and hippocampal cortices. Prior to habituation (Day 2), functional connectivity was only detected (p<0.05) amongst CNS structures known to mediate anxiety (i.e., anterior cingulate (seed region), posterior hypothalamic area, amygdala and parabracial nucleus). In relating functional connectivity between cingulate-default-mode and cingulate-anxiety structures across Days 2-8, a significant inverse relationship (r?=??0.65, p?=?0.0004) was observed between these two functional interactions such that increased cingulate-DMN connectivity corresponded to decreased cingulate anxiety network connectivity. This investigation demonstrates that the cingulate is an important component of both the rodent DMN-like and anxiety networks.

Upadhyay, Jaymin; Baker, Scott J.; Chandran, Prasant; Miller, Loan; Lee, Younglim; Marek, Gerard J.; Sakoglu, Unal; Chin, Chih-Liang; Luo, Feng; Fox, Gerard B.; Day, Mark

2011-01-01

324

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

325

Adaptive Functional Divergence Among Triplicated ?-Globin Genes in Rodents  

PubMed Central

The functional divergence of duplicated genes is thought to play an important role in the evolution of new developmental and physiological pathways, but the role of positive selection in driving this process remains controversial. The objective of this study was to test whether amino acid differences among triplicated ?-globin paralogs of the Norway rat (Rattus norvegicus) and the deer mouse (Peromyscus maniculatus) are attributable to a relaxation of purifying selection or to a history of positive selection that has adapted the gene products to new or modified physiological tasks. In each rodent species, the two paralogs at the 5?-end of the ?-globin gene cluster (HBA-T1 and HBA-T2) are evolving in concert and are therefore identical or nearly identical in sequence. However, in each case, the HBA-T1 and HBA-T2 paralogs are distinguished from the third paralog at the 3?-end of the gene cluster (HBA-T3) by multiple amino acid substitutions. An analysis of genomic sequence data from several rodent species revealed that the HBA-T3 genes of Rattus and Peromyscus originated via independent, lineage-specific duplication events. In the independently derived HBA-T3 genes of both species, a likelihood analysis based on a codon-substitution model revealed that accelerated rates of amino acid substitution are attributable to positive directional selection, not to a relaxation of purifying selection. As a result of functional divergence among the triplicated ?-globin genes in Rattus and Peromyscus, the red blood cells of both rodent species contain a mixture of functionally distinct ?-chain hemoglobin isoforms that are predicted to have different oxygen-binding affinities. In P. maniculatus, a species that is able to sustain physiological function under conditions of chronic hypoxia at high altitude, the coexpression of distinct hemoglobin isoforms with graded oxygen affinities is expected to broaden the permissible range of arterial oxygen tensions for pulmonary/tissue oxygen transport.

Storz, Jay F.; Hoffmann, Federico G.; Opazo, Juan C.; Moriyama, Hideaki

2008-01-01

326

Sleep EEG spectral analysis in a diurnal rodent: Eutamias sibiricus  

Microsoft Academic Search

Summary  \\u000a \\u000a \\u000a \\u000a 1. \\u000a \\u000a Sleep was studied in the diurnal rodentEutamias sibiricus, chronically implanted with EEG and EMG electrodes. Analysis of the distribution of wakefulness, nonrapid eye movement (NREM)\\u000a sleep, and rapid eye movement (REM) sleep over the 24 h period (LD 12?12) showed that total sleep time was 27.5% of recording\\u000a time during the 12 h light period and 74.4% during

Derk Jan Dijk; Serge Daan

1989-01-01

327

Isolation of Actinobacillus lignieresii and Actinobacillus equuli from laboratory rodents.  

PubMed

Actinobacillus lignieresii and Actinobacillus equuli were cultured from a total of 36 guinea pigs, rats, and mice. The organisms were isolated from the oropharynx, the conjunctiva, and middle ear. Isolates were initially screened by eight biochemical tests to determine whether they were of the genus Actinobacillus. Actinobacillus spp. were then differentiated by fermentation reactions of nine carbohydrates. In the past, actinobacilli may have been mistakenly identified as Pasteurella spp., especially Pasteurella pneumotropica. The importance of realizing that Actinobacillus spp. are frequently isolated from laboratory rodents was stressed. PMID:7217333

Lentsch, R H; Wagner, J E

1980-09-01

328

Isolation of Actinobacillus lignieresii and Actinobacillus equuli from laboratory rodents.  

PubMed Central

Actinobacillus lignieresii and Actinobacillus equuli were cultured from a total of 36 guinea pigs, rats, and mice. The organisms were isolated from the oropharynx, the conjunctiva, and middle ear. Isolates were initially screened by eight biochemical tests to determine whether they were of the genus Actinobacillus. Actinobacillus spp. were then differentiated by fermentation reactions of nine carbohydrates. In the past, actinobacilli may have been mistakenly identified as Pasteurella spp., especially Pasteurella pneumotropica. The importance of realizing that Actinobacillus spp. are frequently isolated from laboratory rodents was stressed.

Lentsch, R H; Wagner, J E

1980-01-01

329

Sexual dimorphism in rodent models of hypertension and atherosclerosis  

PubMed Central

Approximately one third of all deaths are attributed to cardiovascular disease (CVD), making it the biggest killer worldwide. Despite a number of therapeutic options available, the burden of CVD morbidity continues to grow indicating the need for continued research to address this unmet need. In this respect, investigation of the mechanisms underlying the protection that premenopausal females enjoy from cardiovascular-related disease and mortality is of interest. In this review, we discuss the essential role that rodent animal models play in enabling this field of research. In particular, we focus our discussion on models of hypertension and atherosclerosis.

Bubb, Kristen J; Khambata, Rayomand S; Ahluwalia, Amrita

2012-01-01

330

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

331

Cecal torsion in rodents associated with chronic administration of clinafloxacin.  

PubMed

The chronic toxicity of clinafloxacin, a fluoroquinolone antibacterial agent, was evaluated in multiple strains of mice and rats. In 5 separate studies, mice and rats that were orally administered up to 1,000 mg/kg of clinafloxacin from 9 to 104 weeks developed dose-related cecal dilatation and deaths that were attributable to cecal torsion. Cecal rupture was observed in association with torsion. Although cecal dilatation is commonly observed in rodents given antibacterials such as fluoroquinolones, cecal torsion has not been a reported sequelae to dilatation. PMID:11026598

Courtney, C L

332

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

333

Gastroenterological emergencies in the tropics.  

PubMed

Significant differences exist in the prevalence of most gastroenterological emergencies in tropical compared with temperate countries. Both ethnic and environmental (often clearly defined geographically) factors are relevant. The major oesophageal lesions which can present acutely in tropical countries are varices and carcinoma; bleeding and obstruction are important sequelae. Peptic ulcer disease (and its complications), often associated (not necessarily causally) with Helicobacter pylori infection, has marked geographical variations in incidence. Emergencies involving the small intestine are dominated by severe dehydration, and its sequelae, resulting from secretory diarrhoea, most notably cholera. However, enteritis necroticans ('pig bel' disease), paralytic ileus (sometimes caused by antiperistaltic agents) and obstruction (secondary to luminal helminths, volvulus and intussusception) are other important problems, especially in infants and children. Enteric fever is occasionally complicated by perforation and haemorrhage; the former (which is notoriously difficult to manage) is accompanied by significant mortality. Ileocaecal tuberculosis is a major cause of right iliac fossa pathology--sometimes associated with malabsorption; amoeboma is an important clinical differential diagnosis. The colon can be involved in invasive Entamoeba histolytica infection (which, like complicated enteric fever, is difficult to manage if the fulminant form, with perforation, ensues), shigellosis, volvulus and intussusception. Acute colonic dilatation occasionally follows Salmonella sp., Shigella sp., Campylobacter jejuni, Yersinia enterocolitica and rarely E. histolytica infections. Acute hepatocellular failure is a major cause of morbidity and mortality in the tropics and subtropics. It usually results from viral hepatitis (HBV, sometimes complicated by HDV, and HCV), but there is a long list of differential diagnoses. Hepatotoxicity resulting from herbs, chemotherapeutic agents or alcohol also occurs not infrequently. Chronic liver disease and its sequelae (often long-term results of viral hepatitis) are commonplace. Haematemesis and hepatocellular failure are usually very difficult to manage due to a lack of sophisticated support techniques in developing countries. Invasive hepatic amoebiasis usually responds well to medical management; however, spontaneous perforation can occur and the consequences of this are serious. Pyogenic liver abscess, although far less common than amoebic 'abscess', carries a bad prognosis whatever the method(s) of management. Hydatidosis and schistosomiasis also involve the liver, and helminthiases are important in the context of biliary tract disease. Gall stones are unusual in most tropical settings. Acute pancreatitis is overall unusual, but chronic calcific pancreatitis can present as an acute abdominal emergency. PMID:1764626

Cook, G C

1991-12-01

334

Tropical forests and atmospheric carbon dioxide  

Microsoft Academic Search

Tropical forests play a major role in determining the current atmospheric concentration of CO2, as both sources of CO2 following deforestation and sinks of CO2 probably resulting from CO2 stimulation of forest photosynthesis. Recently, researchers have tried to quantify this role. The results suggest that both the carbon sources and sinks in tropical forests are significantly greater than previously thought.

Yadvinder Malhi; John Grace

2000-01-01

335

Potential Vorticity Analysis of Tropical Cyclone Intensification  

Microsoft Academic Search

The interaction of marginal Tropical Storm Danny (1985) with an upper-tropospheric positive potential vorticity anomaly was examined. The intensification mechanism proposed earlier for mature Hurricane Elena appears to be valid for Danny as well, despite significant differences in the synoptic-scale environment and in the stage of the tropical cyclone prior to the interaction. Both storms experienced rapid pressure falls as

John Molinari; Steven Skubis; David Vollaro; Frank Alsheimer; Hugh E. Willoughby

1998-01-01

336

Use of phosphate rocks in the tropics  

Microsoft Academic Search

The use of finely ground phosphate rocks (PRs) as directly applied P fertilizers in tropical farming systems is a cheaper alternative to acidulated, water-soluble P products. However, the effectiveness of PRs in tropical environments depends on the extent to which the required P uptake rate of the crop plant can be maintained by the rate of PR dissolution in that

P. W. G. Sale; A. U. Mokwunye

1993-01-01

337

Ancient tropical climates warm San Francisco gathering  

Microsoft Academic Search

Climate records preserved in the Greenland ice sheet got a lot of the attention at the fall meeting of the American Geophysical Union (AGU) in San Francisco last month, but ancient tropical records were a rival attraction. In talks scattered in unrelated sessions, researchers reported a possible role for the tropics in driving the last ice age, a link between

R. Kerr

1994-01-01

338

Monitoring tropical environments with space shuttle photography  

Microsoft Academic Search

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

Michael R. Helfert; Kamlesh P. Lulla

1989-01-01

339

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. At the time of this image Alex had winds estimated at 35 knots (~40.3 mph) and apressure reading of 991 mb.

Holly Zell

2010-06-30

340

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

341

Atmospheric Response Patterns Associated with Tropical Forcing  

Microsoft Academic Search

Atmospheric response patterns associated with tropical forcing are examined with general circulation models driven by global sea surface temperature (SST) variations during 1950-99. Specifically the sensitivity of midlatitude responses to the magnitude and position of tropical SST anomalies is explored. This controversial problem, spanning more than a quarter century now, centers on whether response patterns over the Pacific-North American region

Martin P. Hoerling; Arun Kumar

2002-01-01

342

The changing ecology of tropical forests  

Microsoft Academic Search

The threat to tropical forests is often gauged in terms of deforestation rates and the total area remaining. Recently, however, there has been a growing realization that forest can appear intact on a satellite image yet be biologically degraded or vulnerable to degradation. The array of direct threats to humid tropical forest biodiversity, in addition to deforestation, includes: selective extraction

O. L. Phillips

1997-01-01

343

A View on Tropical Cyclones as CISK  

Microsoft Academic Search

The author's view on tropical cyclones as the conditional instability of the second kind (CISK) is presented. Many theoretical and numerical studies of tropical cyclones have discussed the original CISK of Ooyama (1964, 1969) and Charney and Eliassen (1964) in which frictional convergence plays an important role. In this paper, the author emphasizes that this CISK is applied primarily to

Masanori YAMASAKI

2007-01-01

344

THE UNUSUAL TROPICAL STORM OF JANUARY 1996  

Microsoft Academic Search

Tropical cyclones of the south west Indian Ocean region usually recurve near the eastern African coast and move away to the south east as extra-tropical depressions. A good number are known to cross the African coast once every few years and weaken fast due to friction and insufficient moisture over land. A few have been observed to travel a considerable

O. S. Mudenda; Z. L. S. Mumba

1996-01-01

345

Vorticity balance in East Pacific tropical cyclones  

Microsoft Academic Search

There are still questions about how a tropical cyclone develops out of an unorganized region of convection over the tropical oceans. In this study we investigate the evolution of a few cyclones that developed in the East Pacific during the EPIC2001 and IFEX2005 projects. We have analyzed in those cyclones the relative importance of the terms derived from the vorticity

J. Marin; D. J. Raymond; G. B. Raga

2007-01-01

346

Third-world debt and tropical deforestation  

Microsoft Academic Search

The deforestation and degradation of tropical forests are taking place at an extremely rapid pace. According to the Food and Agriculture Organization (FAO), the estimated annual rate of tropical deforestation during the 1981–1985 period was 113 846 square kilometers or 0.6% of the 1981 total forested area. The implications of the loss of these forests are staggering (Myers, N., 1989.

James R. Kahn; Judith A. McDonald

1995-01-01

347

Greek temples, tropical kine and recombination load  

Microsoft Academic Search

New breeds typically arise from the cross of two or more existing breeds, often chosen to complement each other. For about 100 years, efforts have been made in the tropics to produce a milking breed combining zebu tropical adaptation with taurus production ability. All attempts have failed, although the F1 in nearly all instances has been superior. The Greek Temple

J. J. Rutledge

2001-01-01

348

The Future of Tropical Forest Species1  

Microsoft Academic Search

Deforestation and habitat loss are widely expected to precipitate an extinction crisis among tropical forest species. Humans cause deforestation, and humans living in rural settings have the greatest impact on extant forest area in the tropics. Current human demographic trends, including slowing population growth and intense urbanization, give reason to hope that deforestation will slow, natural forest regeneration through secondary

S. Joseph Wright; Helene C. Muller-Landau

2006-01-01

349

ECOLOGICAL RISK ASSESSMENT FOR AUSTRALIA'S TROPICAL RIVERS  

Microsoft Academic Search

The objective of the Tropical Rivers Inventory and Assessment Project (TRIAP) ecological risk assessment sub-project is to develop a framework applicable to key focus catchments and significant locations that meet stakeholder needs. A broad overview of the major pressures on tropical Australia's aquatic ecosystems will be provided through this sub-project, in addition to more detailed risk assessments for the following

Renee Bartolo; Rick van Dam; Peter Bayliss

350

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."

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

1998-01-01

351

On the Tropical Rainfall Measuring Mission (TRMM)  

Microsoft Academic Search

Summary The importance of quantitative knowledge of tropical rainfall, its associated latent heating and variability is summarized in the context of climate change. Since the tropics are mainly covered with oceans, with some deserts and jungles, the monthly precipitation is not known within a factor of two. Hence the only way to measure it adequately for climate and general circulation

J. Simpson; C. Kummerow; W.-K. Tao; R. F. Adler

1996-01-01

352

Tropical Cyclones: Central North Pacific, 1994.  

National Technical Information Service (NTIS)

The 1994 Central Pacific tropical cyclone season was a near record year for the Central Pacific Hurricane Center (CPHC). A total of 11 tropical cyclones were observed in the Central Pacific. This total included five hurricanes (Emilia, Gilma, Li, John, an...

A. L. Garza G. H. Trapp B. Hablutzel H. E. Rosendal R. Farrell R. Matsuda J. Hoag

1995-01-01

353

Tropical Forests. Global Issues Education Packet.  

ERIC Educational Resources Information Center

Tropical forests provide the world with many products and an incredible diversity of plant and animal life. These forests also provide watershed areas, soil control, climate regulation, and winter homes for migrating birds from North America. It is believed that about 40% of tropical forests have already been destroyed in the last 20-30 years,…

Holm, Amy E.

354

EDITORIAL: Tropical deforestation and greenhouse gas emissions  

Microsoft Academic Search

Carbon emissions from tropical deforestation have long been recognized as a key component of the global carbon budget, and more recently of our global climate system. Tropical forest clearing accounts for roughly 20% of anthropogenic carbon emissions and destroys globally significant carbon sinks (IPCC 2007). Global climate policy initiatives are now being proposed to address these emissions and to more

Holly K. Gibbs; Martin Herold

2007-01-01

355

Prediction of rodent nongenotoxic carcinogenesis: evaluation of biochemical and tissue changes in rodents following exposure to nine nongenotoxic NTP carcinogens.  

PubMed

We studied nine presumed nongenotoxic rodent carcinogens, as defined by the U.S. National Toxicology Program (NTP), to determine their ability to induce acute or subacute biochemical and tissue changes that may act as useful predictors of nongenotoxic rodent carcinogenesis. The chemicals selected included six liver carcinogens (two of which are peroxisome proliferators), three thyroid gland carcinogens, and four kidney carcinogens. We administered the chemicals (diethylhexyl phthalate, cinnamyl anthranilate, chlorendic acid, 1,4-dichlorobenzene, monuron, ethylene thiourea, diethyl thiourea, trimethyl thiourea, and d-limonene to the same strains of mice and rats used in the original NTP bioassays (nine chemicals to rats and seven to mice). Selected tissues (liver, thyroid gland, and kidney) were collected from groups of animals at 7, 28, and 90 days for evaluation. Tissue changes selected for study were monitored for all of the test groups, irrespective of the specificity of the carcinogenic responses observed in those tissues. This allowed us to assess both the carcinogen specificity and the carcinogen sensitivity of the events being monitored. We studied relative weight, cell labeling indices, and pathologic changes such as hypertrophy in all tissues; a range of cytochrome P450 enzymes and palmitoyl coenzyme A oxidase in the liver; changes in the levels of plasma total triiodothyronine, total thyroxine, and thyroid-stimulating hormone (TSH) as markers of thyroid gland function; and hyaline droplet formation, tubular basophilia, and the formation of granular casts in the kidney. There were no single measurements that alerted specifically to the carcinogenicity of the agents to the rodent liver, thyroid gland, or kidney. However, in the majority of cases, the chemical induction of cancer in a tissue was preceded by a range of biochemical/morphologic changes, most of which were moderately specific for a carcinogenic outcome, and some of which were highly specific for it (e.g., increases in TSH in the thyroid gland and increases in relative liver weight in the mouse). The only measurements that failed to correlate usefully with carcinogenicity were the induction of liver enzymes (with the exception of the enzymes associated with peroxisome proliferation). Most of the useful markers were evident at the early times studied (7 days and 28 days), but no overall best time for the measurement of all markers was identified. The judicious choice of markers and evaluation times can aid the detection of potential nongenotoxic rodent carcinogens. PMID:11940454

Elcombe, Clifford R; Odum, Jenny; Foster, John R; Stone, Susan; Hasmall, Susan; Soames, Anthony R; Kimber, Ian; Ashby, John

2002-04-01

356

Prediction of rodent nongenotoxic carcinogenesis: evaluation of biochemical and tissue changes in rodents following exposure to nine nongenotoxic NTP carcinogens.  

PubMed Central

We studied nine presumed nongenotoxic rodent carcinogens, as defined by the U.S. National Toxicology Program (NTP), to determine their ability to induce acute or subacute biochemical and tissue changes that may act as useful predictors of nongenotoxic rodent carcinogenesis. The chemicals selected included six liver carcinogens (two of which are peroxisome proliferators), three thyroid gland carcinogens, and four kidney carcinogens. We administered the chemicals (diethylhexyl phthalate, cinnamyl anthranilate, chlorendic acid, 1,4-dichlorobenzene, monuron, ethylene thiourea, diethyl thiourea, trimethyl thiourea, and d-limonene to the same strains of mice and rats used in the original NTP bioassays (nine chemicals to rats and seven to mice). Selected tissues (liver, thyroid gland, and kidney) were collected from groups of animals at 7, 28, and 90 days for evaluation. Tissue changes selected for study were monitored for all of the test groups, irrespective of the specificity of the carcinogenic responses observed in those tissues. This allowed us to assess both the carcinogen specificity and the carcinogen sensitivity of the events being monitored. We studied relative weight, cell labeling indices, and pathologic changes such as hypertrophy in all tissues; a range of cytochrome P450 enzymes and palmitoyl coenzyme A oxidase in the liver; changes in the levels of plasma total triiodothyronine, total thyroxine, and thyroid-stimulating hormone (TSH) as markers of thyroid gland function; and hyaline droplet formation, tubular basophilia, and the formation of granular casts in the kidney. There were no single measurements that alerted specifically to the carcinogenicity of the agents to the rodent liver, thyroid gland, or kidney. However, in the majority of cases, the chemical induction of cancer in a tissue was preceded by a range of biochemical/morphologic changes, most of which were moderately specific for a carcinogenic outcome, and some of which were highly specific for it (e.g., increases in TSH in the thyroid gland and increases in relative liver weight in the mouse). The only measurements that failed to correlate usefully with carcinogenicity were the induction of liver enzymes (with the exception of the enzymes associated with peroxisome proliferation). Most of the useful markers were evident at the early times studied (7 days and 28 days), but no overall best time for the measurement of all markers was identified. The judicious choice of markers and evaluation times can aid the detection of potential nongenotoxic rodent carcinogens.

Elcombe, Clifford R; Odum, Jenny; Foster, John R; Stone, Susan; Hasmall, Susan; Soames, Anthony R; Kimber, Ian; Ashby, John

2002-01-01

357

Global trends in tropical cyclone risk  

NASA Astrophysics Data System (ADS)

The impact of tropical cyclones on humans depends on the number of people exposed and their vulnerability, as well as the frequency and intensity of storms. How will the cumulative effects of climate change, demography and vulnerability affect risk? Conventionally, reports assessing tropical cyclone risk trends are based on reported losses, but these figures are biased by improvements to information access. Here we present a new methodology based on thousands of physically observed events and related contextual parameters. We show that mortality risk depends on tropical cyclone intensity, exposure, levels of poverty and governance. Despite the projected reduction in the frequency of tropical cyclones, projected increases in both demographic pressure and tropical cyclone intensity over the next 20 years can be expected to greatly increase the number of people exposed per year and exacerbate disaster risk, despite potential progression in development and governance.

Peduzzi, P.; Chatenoux, B.; Dao, H.; de Bono, A.; Herold, C.; Kossin, J.; Mouton, F.; Nordbeck, O.

2012-04-01

358

Variations in rodent models of type 1 diabetes: islet morphology.  

PubMed

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. PMID:23762878

Novikova, Lesya; Smirnova, Irina V; Rawal, Sonia; Dotson, Abby L; Benedict, Stephen H; Stehno-Bittel, Lisa

2013-05-13

359

Holocene vegetation history from fossil rodent middens near Arequipa, Peru  

USGS Publications Warehouse

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 AndesAtacama Desert. The apparent difference in paleoclimatic reconstructions suggests that it is premature to relate changes observed during the Holocene to changes in El Nin??o Southern Oscillation modes. ?? 2001 University of Washington.

Holmgren, C. A.; Betancourt, J. L.; Rylander, K. A.; Roque, J.; Tovar, O.; Zeballos, H.; Linares, E.; Quade, J.

2001-01-01

360

Functional evolution of the feeding system in rodents.  

PubMed

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. PMID:22558427

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

2012-04-27

361

Stress-induced prefrontal reorganization and executive dysfunction in rodents  

PubMed Central

The prefrontal cortex (PFC) mediates a range of higher order ‘executive functions’ that subserve the selection and processing of information in such a way that behavior can be planned, controlled and directed according to shifting environmental demands. Impairment of executive functions typifies many forms of psychopathology, including schizophrenia, mood and anxiety disorders and addiction, that are often associated with a history of trauma and stress. Recent research in animal models demonstrates that exposure to even brief periods of intense stress is sufficient to cause significant structural remodeling of the principle projection neurons within the rodent PFC. In parallel, there is growing evidence that stress-induced alterations in PFC neuronal morphology are associated with deficits in rodent executive functions such as working memory, attentional set-shifting and cognitive flexibility, as well as emotional dysregulation in the form of impaired fear extinction. Although the molecular basis of stress-induced changes in PFC morphology and function are only now being elucidated, an understanding of these mechanisms could provide important insight into the pathophysiology of executive dysfunction in neuropsychiatric disease and foster improved strategies for treatment.

Holmes, Andrew; Wellman, Cara L.

2010-01-01

362

A Practical Guide to Rodent Islet Isolation and Assessment  

PubMed Central

Pancreatic islets of Langerhans secrete hormones that are vital to the regulation of blood glucose and are, therefore, a key focus of diabetes research. Purifying viable and functional islets from the pancreas for study is an intricate process. This review highlights the key elements involved with mouse and rat islet isolation, including choices of collagenase, the collagenase digestion process, purification of islets using a density gradient, and islet culture conditions. In addition, this paper reviews commonly used techniques for assessing islet viability and function, including visual assessment, fluorescent markers of cell death, glucose-stimulated insulin secretion, and intracellular calcium measurements. A detailed protocol is also included that describes a common method for rodent islet isolation that our laboratory uses to obtain viable and functional mouse islets for in vitro study of islet function, beta-cell physiology, and in vivo rodent islet transplantation. The purpose of this review is to serve as a resource and foundation for successfully procuring and purifying high-quality islets for research purposes.

2009-01-01

363

Preparing Undercut Model of Posttraumatic Epileptogenesis in Rodents  

PubMed Central

Partially isolated cortex ("undercut") is an animal model of posttraumatic epileptogenesis. The surgical procedure involves cutting through the sensorimotor cortex and the underneath white matter (undercut) so that a specific region of the cerebral cortex is largely isolated from the neighboring cortex and subcortical regions1-3. After a latency of two or more weeks following the surgery, epileptiform discharges can be recorded in brain slices from rodents1; and electrical or behavior seizures can be observed in vivo from other species such as cat and monkey4-6. This well established animal model is efficient to generate and mimics several important characteristics of traumatic brain injury. However, it is technically challenging attempting to make precise cortical lesions in the small rodent brain with a free hand. Based on the procedure initially established in Dr. David Prince's lab at the Stanford University1, here we present an improved technique to perform a surgery for the preparation of this model in mice and rats. We demonstrate how to make a simple surgical device and use it to gain a better control of cutting depth and angle to generate more precise and consistent results. The device is easy to make, and the procedure is quick to learn. The generation of this animal model provides an efficient system for study on the mechanisms of posttraumatic epileptogenesis.

Xiong, Wenhui; Ping, Xingjie; Gao, Jianhua; Jin, Xiaoming

2011-01-01

364

Utility of animal models for human embryo culture development: rodents.  

PubMed

Advancements in clinical human embryo culture over the last 30-40 years have been supported by research conducted with embryos from rodent and domestic species. The mouse has been the primary rodent species that has contributed to improved embryo culture outcomes. Numerous parameters applied in the beginning of experiments, during progress of experiments, and as end-point measures provide varying degrees of rigor and interpretive strength and/or complexity. A nonexhaustive discussion of these parameters is presented with important emphasis on experimental design to obtain the greatest power of intraexperimental interpretation of inferior, equivalent, or improved culture conditions in the mouse model. Additionally, data are presented demonstrating the inherent flaw of overinterpretation of interexperimental outcome comparisons and caution of expectations of data translation from the mouse to the human embryo culture scenario. Finally, a materials, methods, and notes discussion enumerates important steps in use of mouse embryos as a bioassay tool, independent of whether they are being used in an experiment focused on quality control or improving culture conditions. PMID:22829366

Smith, Gary D

2012-01-01

365

Studying autism in rodent models: reconciling endophenotypes with comorbidities.  

PubMed

Autism spectrum disorder (ASD) patients commonly exhibit a variety of comorbid traits including seizures, anxiety, aggressive behavior, gastrointestinal problems, motor deficits, abnormal sensory processing, and sleep disturbances for which the cause is unknown. These features impact negatively on daily life and can exaggerate the effects of the core diagnostic traits (social communication deficits and repetitive behaviors). Studying endophenotypes relevant to both core and comorbid features of ASD in rodent models can provide insight into biological mechanisms underlying these disorders. Here we review the characterization of endophenotypes in a selection of environmental, genetic, and behavioral rodent models of ASD. In addition to exhibiting core ASD-like behaviors, each of these animal models display one or more endophenotypes relevant to comorbid features including altered sensory processing, seizure susceptibility, anxiety-like behavior, and disturbed motor functions, suggesting that these traits are indicators of altered biological pathways in ASD. However, the study of behaviors paralleling comorbid traits in animal models of ASD is an emerging field and further research is needed to assess altered gastrointestinal function, aggression, and disorders of sleep onset across models. Future studies should include investigation of these endophenotypes in order to advance our understanding of the etiology of this complex disorder. PMID:23898259

Argyropoulos, Andrew; Gilby, Krista L; Hill-Yardin, Elisa L

2013-07-25

366

Spatial memory tasks in rodents: what do they model?  

PubMed

The analysis of spatial learning and memory in rodents is commonly used to investigate the mechanisms underlying certain forms of human cognition and to model their dysfunction in neuropsychiatric and neurodegenerative diseases. Proper interpretation of rodent behavior in terms of spatial memory and as a model of human cognitive functions is only possible if various navigation strategies and factors controlling the performance of the animal in a spatial task are taken into consideration. The aim of this review is to describe the experimental approaches that are being used for the study of spatial memory in rats and mice and the way that they can be interpreted in terms of general memory functions. After an introduction to the classification of memory into various categories and respective underlying neuroanatomical substrates, I explain the concept of spatial memory and its measurement in rats and mice by analysis of their navigation strategies. Subsequently, I describe the most common paradigms for spatial memory assessment with specific focus on methodological issues relevant for the correct interpretation of the results in terms of cognitive function. Finally, I present recent advances in the use of spatial memory tasks to investigate episodic-like memory in mice. PMID:23793547

Morellini, Fabio

2013-06-22

367

Visual landmarks facilitate rodent spatial navigation in virtual reality environments  

PubMed Central

Because many different sensory modalities contribute to spatial learning in rodents, it has been difficult to determine whether spatial navigation can be guided solely by visual cues. Rodents moving within physical environments with visual cues engage a variety of nonvisual sensory systems that cannot be easily inhibited without lesioning brain areas. Virtual reality offers a unique approach to ask whether visual landmark cues alone are sufficient to improve performance in a spatial task. We found that mice could learn to navigate between two water reward locations along a virtual bidirectional linear track using a spherical treadmill. Mice exposed to a virtual environment with vivid visual cues rendered on a single monitor increased their performance over a 3-d training regimen. Training significantly increased the percentage of time avatars controlled by the mice spent near reward locations in probe trials without water rewards. Neither improvement during training or spatial learning for reward locations occurred with mice operating a virtual environment without vivid landmarks or with mice deprived of all visual feedback. Mice operating the vivid environment developed stereotyped avatar turning behaviors when alternating between reward zones that were positively correlated with their performance on the probe trial. These results suggest that mice are able to learn to navigate to specific locations using only visual cues presented within a virtual environment rendered on a single computer monitor.

Youngstrom, Isaac A.; Strowbridge, Ben W.

2012-01-01

368

Seasonal variation in telomere length of a hibernating rodent.  

PubMed

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. PMID:23389666

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

2013-02-06

369

Protection by dietary compounds against mutation in a transgenic rodent.  

PubMed

One of the most relevant biomarkers of genotoxicity and, potentially, carcinogenesis is the occurrence of mutations. Data indicate that carcinogens are highly specific with regard to their target tissue in inducing both tumors and mutations. This specificity may reflect the dependence on tissue-specific metabolic activation, the organ-specific environment or both. Ideally, therefore, mutation should be determined in a real animal rather than in a cell culture system. The lacI transgenic rodent model provides such a system. We have used this model to investigate tissue, species and sex specificity of mutation induced by selected dietary carcinogens and to examine how some compounds may alter the induction of mutation. We have studied mutation using several chemicals, including the dietary heterocyclic amine 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), the environmentally important aromatic hydrocarbon benzo[a]pyrene and the food contaminant aflatoxin B1. We have shown that the mutagenic potency of these chemicals can be modulated by other dietary compounds, including green tea and conjugated linoleic acid, and the dioxin 2,3,7,8-tetrachlorodibenzo[b,e][1,4]dioxin (TCDD). These results demonstrate that the lacI transgenic rodent is a useful model for the study of chemoprevention in vivo. PMID:11694652

de Boer, J G

2001-11-01

370

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

371

Mission Investigates Tropical Cirrus Clouds  

NASA Astrophysics Data System (ADS)

It has been a year since NASA conducted the highly successful Cirrus Regional Study of Tropical Anvils and Cirrus Layers-Florida Area Cirrus Experiment Study (CRYSTAL-FACE). The measurement campaign was designed to investigate the physical properties and formation processes of tropical cirrus clouds. CRYSTAL-FACE was sponsored by NASA's Earth Science Enterprise as an integral component of its Earth observation research strategy, and included substantial collaboration with the National Oceanic and Atmospheric Administration, the National Science Foundation, the Department of Energy, and the Naval Research Laboratory. During July 2002, the mission's six aircraft (NASA ER-2, NASA WB-57, Scaled Composites Proteus, University of North Dakota Citation, NSF-supported NRL P-3, and NRL Twin Otter) operated from the Key West Naval Air Facility. In addition, ground sites were located at the Tamiami airport on the east coast of Florida and near Everglades City on the west coast of Florida. Aircraft and ground site measurements are listed in Table 1. Data archiving is complete, and the data are now available to the general scientific community. Detailed instrument descriptions as well as the final data can be found on the CRYSTAL-FACE Web site (http://cloud1.arc.nasa.gov/crystalface/).

Jenson, Eric; Starr, David; Toon, Owen B.

2004-02-01

372

Epizootiology of tropical canine pancytopenia.  

PubMed

Tropical canine pancytopenia (TCP) is a newly recognized infectious disease of dogs in diverse tropical and subtropical areas. The disease is characterized by hemorrhage, pancytopenia, severe emaciation and persistent infection. Dogs with TCP are often presented with epistaxis, which is the most dramatic sign of the disease; however, a large number of affected dogs develop severe pancytopenia and die without manifesting clinical signs of hemorrhage. The disease has been reported most frequently in the German Shepherd. Pathological findings consist of petechial and ecchymotic hemorrhages on serosal and mucosal surfaces of numerous organs. The most prominent histological finding is a perivascular plasma cell infiltrate in most organs. Disease, indistinguishable from the natural disease, has been produced in laboratory dogs inoculated with whole blood from affected dogs. Ehrlichia canis has been consistently recovered from all experimentally infected dogs. Attempts to transmit the disease to other laboratory animals and to propagate the agent in cell cultures and embryonating eggs have been unsuccessful. The tick is the probable vector of the disease. PMID:16512116

Huxsoll, D L; Hildebrandt, P K; Nims, R M; Amyx, H L; Ferguson, J A

1970-10-01

373

RODENT COMMUNITIES IN ACTIVE AND INACTIVE COLONIES OF BLACK-TAILED PRAIRIE DOGS IN SHORTGRASS STEPPE  

Microsoft Academic Search

Black-tailed prairie dogs (Cynomys ludovicianus) alter shortgrass-steppe landscapes in ways that are expected to affect other mammals. I sampled rodent populations at 31 sites on the Pawnee National Grasslands, Colorado, including 18 active colonies, 6 colonies that had been unoccupied for .6 years (inactive), and 7 grassland sites without prairie dogs (controls). Rodents were livetrapped for 4 consecutive nights at

Paul Stapp

2007-01-01

374

Observations on Natural and Laboratory Infection of Rodents with the Etiologic Agent of Korean Hemorrhagic Fever.  

National Technical Information Service (NTIS)

Studies were conducted to define the natural host range of Korean hemorrhagic fever (KHF) agent in South Korea, and to identify colonized rodents susceptible to this infection. Eight species of field rodents were captured in areas of Korea endemic for KHF...

H. W. Lee G. R. French P. W. Lee L. J. Baek K. Tsuchiya

1980-01-01

375

New observations on urine contents in water-deprived Negev Desert rodents  

Microsoft Academic Search

In past studies, several rodent species of the murid subfamilies Gerbillinae and Cricetomyinae from the Namib Desert, when deprived of water, excreted allantoin precipitate in their urine. Shifting nitrogen excretion from urea to allantoin allows them to save much water. This phenomenon has not been reported in other rodents, and whether it is a trait that is common among desert

Carmi Korine; Itzick Vatnick; Ian G. van Tets; Berry Pinshow

2003-01-01

376

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...

377

Late Miocene–Early Pliocene temperature estimates in Europe using rodents  

Microsoft Academic Search

Studies of mammal communities, and in particular of rodents, provide useful information on palaeoenvironments and palaeoclimates. Based on the relationship between species richness and climatic parameters, we propose three models, using arvicolines, murines or sigmodontines in order to quantify past temperatures. Based on rodents, temperatures are estimated here for Late Miocene–Early Pliocene (MN 9 to MN 15) European faunas at

Sophie Montuire; Olivier Maridet; Serge Legendre

2006-01-01

378

Models for an arenavirus infection in a rodent population: consequences of horizontal, vertical and sexual transmission  

Microsoft Academic Search

Arenaviruses are associated with rodent-transmitted diseases in humans. Five arenaviruses are known to cause human illness: Lassa virus, Junin virus, Machupo virus, Guanarito virus and Sabia virus. In this inves- tigation, we model the spread of Machupo virus in its rodent host Calomys callosus. Machupo virus infection in humans is known as Bolivian hemorrhagic fever (BHF) which has a mortality

Jorge Salazar-Bravo; Chandrani Banerjee; Linda Allen

2008-01-01

379

Knowledge-Based Learning in Exploratory Science: Learning Rules to Predict Rodent Carcinogenicity  

Microsoft Academic Search

In this paper, we report on a multi-year collaboration among computer scientists, toxicologists, chemists, and a statistician, in which the RL induction program was used to assist toxicologists in analyzing relationships among various features of chemical compounds and their carcinogenicity in rodents. Our investigation demonstrated the utility of knowledge-based rule induction in the problem of predicting rodent carcinogenicity and the

Yongwon Lee; Bruce G. Buchanan; John M. Aronis

1998-01-01

380

The Preparation of Microsomal Fractions of Rodent Respiratory Tract and Their Characterization1  

Microsoft Academic Search

SUMMARY A method for preparing rodent lung microsomes using normal differential centrifugation methods is described which allows the spectral characterization of these lung fractions. Further, procedures have been established to quantitate the microsomal cytochromes bs and P-450 in microsomes, which contain appreciable amounts of con taminating hemoglobin and methemoglobin. Physical bio chemical characterizations of the rodent lung microsomal cytochromes include

T. Matsubara; R. A. Prough; M. D. Burke; R. W. Estabrook

381

Effectiveness of six species of rodents as dispersers of singleleaf piñon pine ( Pinus monophylla )  

Microsoft Academic Search

The effectiveness of six species of rodents as dispersers of singleleaf piñon pine (Pinus monophylla) was investigated in field enclosures. The rodent species were Panamint kangaroo rat (Dipodomys panamintinus), Great Basin pocket mouse (Perognathus parvus), pinyon mouse (Peromyscus truei), deer mouse (Peromyscus maniculatus), least chipmunk (Tamias minimus), and white-tailed antelope ground squirrel (Ammospermophilus leucurus). Five measures of seed harvesting and

Jennifer L. Hollander; Stephen B. Vander Wall

2004-01-01

382

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.

383

42 CFR 71.56 - African rodents and other animals that may carry the monkeypox virus.  

Code of Federal Regulations, 2011 CFR

...2011-10-01 false African rodents and other animals that may carry the monkeypox virus... § 71.56 African rodents and other animals that may carry the monkeypox virus. (a) What actions are prohibited? What animals are affected? (1) Except as...

2011-10-01

384

42 CFR 71.56 - African rodents and other animals that may carry the monkeypox virus.  

Code of Federal Regulations, 2012 CFR

...2012-10-01 false African rodents and other animals that may carry the monkeypox virus... § 71.56 African rodents and other animals that may carry the monkeypox virus. (a) What actions are prohibited? What animals are affected? (1) Except as...

2012-10-01

385

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

386

Disposable plastic rodent feeders for use in an automated filling system  

Microsoft Academic Search

Rodent feeder devices are often made of reusable, sanitizable materials such as glass and stainless steel. As part of an initiative at the authors' facility to automate the feeder filling process, disposable plastic feeding cups were proposed as a preferable alternative to standard feeders for use in a filling machine. The authors tested and validated designs for rodent meal-type feeder

David Gleason; Lisa Clare; Susan Buckham; Robert DeWit; James Toler

2008-01-01

387

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

388

Phylogenetic Relationships and the Radiation of Sigmodontine Rodents in South America: Evidence from Cytochrome b  

Microsoft Academic Search

Phylogenetic relationships among South American sigmodontine rodents were examined based on the complete sequence for the mitochondrial cytochrome b gene [1140 base pairs (bp)] for 66 species and between 759 and 1140 bp for an additional 19 species. Thirty-eight South American genera were represented, coming from eight of nine tribes. Outgroups included the North American murid rodents Peromyscus, Reithrodontomys, Scotinomys,

Margaret F. Smith; James L. Patton

1999-01-01

389

Molecular evolution of the nuclear von Willebrand factor gene in mammals and the phylogeny of rodents.  

PubMed

Nucleotide sequences of exon 28 of the von Willebrand Factor (vWF) were analyzed for a representative sampling of rodent families and eutherian orders, with one marsupial sequence as outgroup. The aim of this study was to test if inclusion of an increased taxonomic diversity in molecular analyses would shed light on three uncertainties concerning rodent phylogeny: (1) relationships between rodent families, (2) Rodentia monophyly, and (3) the sister group relationship of rodents and lagomorphs. The results did not give evidence of any particular rodent pattern of molecular evolution relative to a general eutherian pattern. Base compositions and rates of evolution of vWF sequences of rodents were in the range of placental variation. The 10 rodent families studied here cluster in five clades: Hystricognathi, Sciuridae and Aplodontidae (Sciuroidea), Muridae, Dipodidae, and Gliridae. Among hystricognaths, the following conclusions are drawn: a single colonization event in South America by Caviomorpha, a paraphyly of Old World and New World porcupines, and an African origin for Old World porcupines. Despite a broader taxonomic sampling diversity, we did not obtain a robust answer to the question of Rodentia monophyly, but in the absence of any other alternative, we cannot reject the hypothesis of a single origin of rodents. Moreover, the phylogenetic position of Lagomorpha remains totally unsettled. PMID:10335651

Huchon, D; Catzeflis, F M; Douzery, E J

1999-05-01

390

Estimation of Wildlife Hazard Levels Using Interspecies Correlation Models and Standard Laboratory Rodent Toxicity Data  

EPA Science Inventory

Toxicity data from laboratory rodents are widely available and frequently used in human health assessments as an animal model. We explore the possibility of using single rodent acute toxicity values to predict chemical toxicity to a diversity of wildlife species and to estimate ...

391

South America's earliest rodent and recognition of a new interval of mammalian evolution  

Microsoft Academic Search

THE mid-Cenozoic immigration of rodents and primates to South America (when it was widely isolated by oceans) represents a pre-eminent problem in the biogeographical history of placental mammals. The unexpected discovery of South America's earliest rodent in the central Chilean Andes provides information critical to resolving the source area and primitive morphology of South American caviomorphs, suggesting an African origin

André R. Wyss; John J. Flynn; Mark A. Norell; Carl C. Swisher; Reynaldo Charrier; Michael J. Novacek; Malcolm C. McKenna

1993-01-01

392

Geographic Distribution of Hantaviruses Associated with Neotomine and Sigmodontine Rodents, Mexico  

PubMed Central

To increase our knowledge of the geographic distribution of hantaviruses associated with neotomine or sigmodontine rodents in Mexico, we tested 876 cricetid rodents captured in 18 Mexican states (representing at least 44 species in the subfamily Neotominae and 10 species in the subfamily Sigmodontinae) for anti-hantavirus IgG. We found antibodies against hantavirus in 35 (4.0%) rodents. Nucleotide sequence data from 5 antibody-positive rodents indicated that Sin Nombre virus (the major cause of hantavirus pulmonary syndrome [HPS] in the United States) is enzootic in the Mexican states of Nuevo León, San Luis Potosí, Tamaulipas, and Veracruz. However, HPS has not been reported from these states, which suggests that in northeastern Mexico, HPS has been confused with other rapidly progressive, life-threatening respiratory diseases. Analyses of nucleotide sequence data from 19 other antibody-positive rodents indicated that El Moro Canyon virus and Limestone Canyon virus are geographically widely distributed in Mexico.

Milazzo, Mary L.; Cajimat, Maria N.B.; Romo, Hannah E.; Estrada-Franco, Jose G.; Iniguez-Davalos, L. Ignacio; Bradley, Robert D.

2012-01-01

393

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

2012-11-23

394

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

395

Coxiella burnetii in rodents on Heixiazi Island at the Sino-Russian border.  

PubMed

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. PMID:23382172

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

2013-02-04

396

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

397

Effects of fat and protein levels on foraging preferences of tannin in scatter-hoarding rodents.  

PubMed

Both as consumers and dispersers of seeds, scatter-hoarding rodents often play an important role in the reproductive ecology of many plant species. However, the seeds of many plant species contain tannins, which are a diverse group of water-soluble phenolic compounds that have a high affinity for proteins. The amount of tannins in seeds is expected to affect rodent foraging preferences because of their major impact on rodent physiology and survival. However, variable results have been obtained in studies that evaluated the effects of tannin on rodent foraging behavior. Hence, in this study, we aimed to explain these inconsistent results and proposed that a combination of seed traits might be important in rodent foraging behavior, because it is difficult to distinguish between the effects of individual traits on rodent foraging behavior and the interactions among them. By using a novel artificial seed system, we manipulated seed tannin and fat/protein levels to examine directly the univariate effects of each component on the seed preferences of free-ranging forest rats (Apodemus latronum and Apodemus chevrieri) during the behavioral process of scatter hoarding. Our results showed that both tannin and fat/protein had significant effects on rodent foraging behavior. Although only a few interactive effects of tannin and fat/protein were recorded, higher concentrations of both fat and protein could attenuate the exclusion of seeds with higher tannin concentrations by rodents, thus influencing seed fate. Furthermore, aside from the concentrations of tannin, fat, and protein, numerous other traits of plant seeds may also influence rodent foraging behavior. We suggest that by clarifying rodent foraging preferences, a better understanding of the evolution of plant seed traits may be obtained because of their strong potential for selective pressure. PMID:22808217

Wang, Bo; Chen, Jin

2012-07-10

398

Next-generation sequencing for rodent barcoding: species identification from fresh, degraded and environmental samples.  

PubMed

Rodentia is the most diverse order among mammals, with more than 2,000 species currently described. Most of the time, species assignation is so difficult based on morphological data solely that identifying rodents at the specific level corresponds to a real challenge. In this study, we compared the applicability of 100 bp mini-barcodes from cytochrome b and cytochrome c oxidase 1 genes to enable rodent species identification. Based on GenBank sequence datasets of 115 rodent species, a 136 bp fragment of cytochrome b was selected as the most discriminatory mini-barcode, and rodent universal primers surrounding this fragment were designed. The efficacy of this new molecular tool was assessed on 946 samples including rodent tissues, feces, museum samples and feces/pellets from predators known to ingest rodents. Utilizing next-generation sequencing technologies able to sequence mixes of DNA, 1,140 amplicons were tagged, multiplexed and sequenced together in one single 454 GS-FLX run. Our method was initially validated on a reference sample set including 265 clearly identified rodent tissues, corresponding to 103 different species. Following validation, 85.6% of 555 rodent samples from Europe, Asia and Africa whose species identity was unknown were able to be identified using the BLASTN program and GenBank reference sequences. In addition, our method proved effective even on degraded rodent DNA samples: 91.8% and 75.9% of samples from feces and museum specimens respectively were correctly identified. Finally, we succeeded in determining the diet of 66.7% of the investigated carnivores from their feces and 81.8% of owls from their pellets. Non-rodent species were also identified, suggesting that our method is sensitive enough to investigate complete predator diets. This study demonstrates how this molecular identification method combined with high-throughput sequencing can open new realms of possibilities in achieving fast, accurate and inexpensive species identification. PMID:23144869

Galan, Maxime; Pagès, Marie; Cosson, Jean-François

2012-11-07

399

Ground-based rodent control in a remote Hawaiian rainforest on Maui  

USGS Publications Warehouse

Effective control of introduced mammalian predators is essential to the recovery of native bird species in Hawai'i. Between August 1996 and December 2004, introduced rodents were controlled within three home ranges of the Po'ouli Melamprosops phaeosoma, a critically endangered Hawaiian honeycreeper. Rats were controlled using a combination of ground-based rodenticide (0.005% diphacinone) application and snap traps. Beginning in August 2001, we monitored the effectiveness of these rodent control efforts. Relative abundances of Black Rats Rattus rattus and Polynesian Rats R. exulans were measured in each of five snap-trapping grids seven times over a 35-month period. Rat populations decreased inside of the rodent control areas, but control effectiveness differed between rat species. During the first year of monitoring, target control levels for R. rattus were consistently achieved in only one of the rodent control areas. Control techniques were refined in areas failing to meet targets. Subsequently, we achieved target control levels for R. rattus more consistently in all three rodent control areas. However, relative abundances of R. exulans did not differ between rodent control and reference areas, indicating that our rodent control techniques were insufficient to reduce population levels of this species. These findings signify a need for further improvement of rodent control methods in Hawai'i, especially for Polynesian Rats, and demonstrate the critical importance of periodic monitoring of the response of rodent populations to management. In the future, managers may need to design rodent control operations targeting R. rattus and R. exulans independently to achieve best results.

Malcolm, T. R.; Swinnerton, K. J.; Groombridge, J. J.; Sparklin, B. D.; Brosius, C. N.; Vetter, J. P.; Foster, J. T.

2008-01-01

400

Rodent and Flea Abundance Fail to Predict a Plague Epizootic in Black-Tailed Prairie Dogs  

PubMed Central

Abstract Small rodents are purported to be enzootic hosts of Yersinia pestis and may serve as sources of infection to prairie dogs or other epizootic hosts by direct or flea-mediated transmission. Recent research has shown that small rodent species composition and small rodent flea assemblages are influenced by the presence of prairie dogs, with higher relative abundance of both small rodents and fleas at prairie dog colony sites compared to grasslands without prairie dogs. However, it is unclear if increased rodent or flea abundance predisposes prairie dogs to infection with Y. pestis. We tracked rodent and flea occurrence for 3 years at a number of prairie dog colony sites in Boulder County, Colorado, before, during, and after a local plague epizootic to see if high rodent or flea abundance was associated with plague-affected colonies when compared to colonies that escaped infection. We found no difference in preepizootic rodent abundance or flea prevalence or abundance between plague-positive and plague-negative colonies. Further, we saw no significant before-plague/after-plague change in these metrics at either plague-positive or plague-negative sites. We did, however, find that small rodent species assemblages changed in the year following prairie dog die-offs at plague-affected colonies when compared to unaffected colonies. In light of previous research from this system that has shown that landscape features and proximity to recently plagued colonies are significant predictors of plague occurrence in prairie dogs, we suggest that landscape context is more important to local plague occurrence than are characteristics of rodent or flea species assemblages.

Collinge, Sharon K.; Ray, Chris; Gage, Ken L.

2010-01-01

401

Acute kidney injury in the tropics  

PubMed Central

Acute kidney injury (AKI) is one of the most challenging problems faced by clinicians in the tropics owing to its fast-changing burden. AKI in the tropics is strikingly different from that in the developed world in terms of etiology and presentation. In addition, there is a stark contrast between well-developed and poor areas in the tropics. The true epidemiological picture of AKI in the tropics is not well understood due to the late presentation of patients to tertiary centers. Infections remain the major culprit in most cases of AKI, with high mortality rates in the tropics. Human immunodeficiency virus–related AKI, related to nephrotoxicity due to antiretroviral therapy, is on the rise. Acute tubular necrosis and thrombotic microangiopathy are the most common mechanisms of AKI. A notable problem in the tropics is the scarcity of resources in health centers to support patients who require critical care due to AKI. This article reviews the unique and contrasting nature of AKI in the tropics and describes its management in each situation.

Mathew, Ashish Jacob; George, Jacob

2011-01-01

402

Basal rate of metabolism and temperature regulation of two desert herbivorous octodontid rodents: Octomys mimax and Tympanoctomys barrerae  

Microsoft Academic Search

We studied the energetics of two herbivorous desert rodents from South America. The two species had slightly lower basal metabolic rates, lower thermal conductances, and higher temperature differentials than those expected from their body mass. Mass-independent basal rates of metabolism were higher than those reported for seed-eating desert rodents from North America. Our observations support the hypothesis that desert rodents

Francisco Bozinovic; Luis C. Contreras

1990-01-01

403

World Health Organization: Tropical Disease Research  

NSDL National Science Digital Library

The swath of the earth lying between the Tropic of Cancer and the Tropic of Capricorn is home to a variety of severe endemic diseases including: malaria, dracunculiasis or Guinea-worm disease, schistolomiasis, trematode infections, onchocerciasis, leishmaniasis, denge fever, and sleeping sickness. The control and future eradication of these diseases is the primary goal of the WHO Division of Control of Tropical Diseases and this site provides basic information on the epidemiology, biology and potential treatments for such diseases. Statistics on the incidence and history of this group of diseases are also included as well as the WHO strategy for eliminating them.

1997-01-01

404

Tropical Cyclones: Hurricane Mitch Fact Sheet  

NSDL National Science Digital Library

Hurricane Mitch developed in the Caribbean Sea in October 1998 and became one of the strongest and deadliest Atlantic hurricanes ever recorded. Some of the details of the hurricane and its effects are summarized including its origin, life cycle, records, and cost. Links lead to five images, including a distant view on 26 October 1998, a close up on 26 October 1998, a movie loop from tropical wave to extra-tropical storm (19 October to 07 November), the observed track from 23 October to 06 November and the observed tracks of all Atlantic tropical cyclones in 1998. Additional links lead to sites for more meteorological and humanitarian information.

405

Mars: destructive and constructive processes in its crust reflecting tendencies of leveling angular momenta of tropics and extra-tropics  

Microsoft Academic Search

Mars: destructive and constructive processes in its crust reflecting tendencies of leveling angular momenta of tropics and extra-tropics. G. Kochemasov IGEM of the Russian Academy of Sciences A globular shape of rotating celestial bodies means that their tropical and extra-tropical belts have significantly different angular momenta. But such unevenness in a single body is disturbing because it increases level of

G. G. Kochemasov

2009-01-01

406

?-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

407

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

408

A new rodent behavioral paradigm for studying forelimb movement  

PubMed Central

The center-out task is a standard paradigm often used to study the neural control of reaching movements in human and non-human primates. However, there are several disadvantages to the use of monkeys, notably costs, infrastructural requirements, and ethical considerations. Here we describe a similar task designed to examine forelimb movements in rats. Rats were trained to grasp a joystick with their forepaw and use it to control the movements of a sipper tube in two dimensions. The rats learned to move the joystick in four directions with at least 70% accuracy after about 45 days of training. In addition, rats were able to learn a reversed mapping between joystick and sipper tube movement. This is a more complicated behavior than has been previously demonstrated for rats, and it could allow more motor behavior studies to be conducted in rodents instead of monkeys. We currently are using this behavior to decode the rats’ forelimb movements from their brain signals.

Slutzky, Marc W.; Jordan, Luke R.; Bauman, Matthew J.; Miller, Lee E.

2010-01-01

409

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

410

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

2013-09-20

411

Insulin Glargine: A Reevaluation of Rodent Carcinogenicity Findings  

PubMed Central

The 1995 to 1997 lifetime carcinogenicity studies of insulin glargine in rats and mice were reanalyzed and reassessed for their validity according to current guidelines. In 2-year studies, 50 animals per sex and per group were used. Survival rates between weeks 80 and 90 in female mice and rats were greater than 20 animals in all groups, fulfilling current Food and Drug Administration requirements that enough animals lived long enough to provide adequate exposure to glargine and to be at risk of forming late-developing tumors. Exposure to 5 or 12.5 IU/kg glargine was similar to or 2 to 3 times greater than 5 IU/kg neutral protamine Hagedorn insulin, respectively. Using statistical methods recommended by current guidelines, no significant effect of glargine on mammary gland neoplastic lesions in female rodents was found, confirming earlier results. Thus, both studies can be considered valid according to contemporary standards. Insulin glargine does not present a carcinogenic risk.

Stammberger, Ingo; Essermeant, Luc

2012-01-01

412

Rodent models of heart failure: an updated review.  

PubMed

Heart failure (HF) is one of the major health and economic burdens worldwide, and its prevalence is continuously increasing. The study of HF requires reliable animal models to study the chronic changes and pharmacologic interventions in myocardial structure and function and to follow its progression toward HF. Indeed, during the past 40 years, basic and translational scientists have used small animal models to understand the pathophysiology of HF and find more efficient ways of preventing and managing patients suffering from congestive HF (CHF). Each species and each animal model has advantages and disadvantages, and the choice of one model over another should take them into account for a good experimental design. The aim of this review is to describe and highlight the advantages and drawbacks of some commonly used HF rodents models, including both non-genetically and genetically engineered models, with a specific subchapter concerning diastolic HF models. PMID:22446984

Gomes, A C; Falcão-Pires, I; Pires, A L; Brás-Silva, C; Leite-Moreira, A F

2013-03-01

413

[Seasonal changes in the energy metabolism of subarctic rodents].  

PubMed

In widespread species, northern taiga voles, most significant differences in the intensity of energy metabolism (M), maximum (Mmax) and reserve (Mres) metabolism were observed at winter temperatures (-5-20 degrees C): Clethrionomys rutilus greater than C. rufocanus greater than Microtus oeconomus; differences in seasonal increase of Mmax and Mres exhibit an inverse proportion. Seasonal changes in M and Mmax in autochthonous tundra rodents indicate that Lemmus sibiricus belongs to a more eurybiont species as compared to Dicrostonyx torquatus. The main characteristic feature of seasonal adaptation of M in lemmings, as compared to voles, is the evident decrease of M value in winter which is accompanied by a more significant increase of Mmax and Mres. Operative pattern and high seasonal mobility of chemical thermoregulation in lemmings are suggested which account for adaptation of these animals mainly to short-term extreme effects of low temperatures. PMID:2596207

Pastukhov, Iu F; Belogubova, E G

414

Designing a Tropical Reserve System  

NSDL National Science Digital Library

An optimally designed biological reserve system requires the integration and application of knowledge from several sources. Students are given a map of a region of some tropical country with a list of important geographic and biological information about the areas; a set of specific need, limitations, and governmental objectives are also provided. Each student is assigned a specific role and is placed within a larger planning group. The individual must see that his or her specific needs are addressed. The group task is to design and locate a set of conservation areas that best accommodates as many of the stated needs and priorities as possible. The group must present, explain, and defend their plan to the class or discussion.

BEGIN:VCARD VERSION:2.1 FN:James R Serach N:R Serach;James ORG:Lawrence Academy REV:2005-04-15 END:VCARD

1995-06-30

415

Bromoform in the tropical Atlantic  

NASA Astrophysics Data System (ADS)

Sea-to-air emissions of reactive, brominated halocarbons, of which bromoform (CHBr3) is the major organic source for atmospheric reactive bromine, are controlled by biotic and abiotic production and consumption processes in the water. These compounds affect the 'oxidising capacity' of the lower atmosphere, primarily as a result of their influence on the ozone concentration. Besides a large macroalgal source in coastal regions, oversaturation in the worlds open oceans contributes significantly to the global emissions, suggesting an yet unknown open ocean source. Atmospheric studies in the Pacific and Atlantic have revealed maxima of tropospheric bromoform concentrations in equatorial regions, suggesting enhanced surface sources in these waters. The responsible processes and fluxes in the open ocean are generally poorly characterised. A west to east transect along 10°N including a short meridional transect into the equatorial upwelling was conducted in the tropical Atlantic Ocean from Curacao to Doualla with R/V Meteor in October /November 2002 (ME55). Surface samples and samples from shallow hydro casts (<500 m) were analysed on board for the brominated compounds dibromomethane (CH2Br2), dibromochloromethane (CHBr2Cl), dichlorobromomethane (CHBrCl2) and bromoform (CHBr3), using purge-and-trap gas chromatography with mass spectrometry. Preliminary results for bromoform show background concentrations of 2-4 pmol/L in the surface ocean and 1-2 pmol/L in deeper layers. Elevated concentrations of 8 to 14 pmol/L bromoform were observed in the area of equatorial upwelling. Maxima up to 30 pmol/L bromoform were always found underneath the mixed layer and seem to be associated with the chlorophyll maximum in 40 to 70 m depth. The highest concentrations of CHBr3 (2nmol/L) as well as of CHBr2Cl, CHBrCl2 and CHCl3 were discovered in the Amazone river plume at the boundary between the river and ocean waters around 40 m depth. Ancillary profile data such as productivity, chlorophyll a and other pigments, species composition, dissolved organic carbon (DOC), particulate organic carbon (POC), oxygen, nutrients (N,P,Si) and hydrogenperoxide (H2O2) are available. Correlations with the halocarbon data will be evaluated in the near future, which may help to understand the deep maximum of bromoform and determine sources of the brominated methanes. Air samples were taken and concentrations of the halocarbons will be analysed by the groups of Elliot Atlas (NCAR, Boulder) and James H. Butler (NOAA, Boulder) to reveal the saturation-anomalies and the air-sea fluxes of the compounds from the tropical oceanic surface waters. Preliminary results of our measurements show background concentrations of bromoform below 1 ppt , which make the tropical ocean waters a general source of this compound for the atmosphere. In the following months we will incorporated the air-sea fluxes, photochemical data (JNO2) and bromine oxide (BrO), obtained during the cruise in an atmospheric model, to investigate the contribution of tropical bromofrom and other compounds to the atmospheric reactive bromine budget.

Quack, B.; Wallace, D.

2003-04-01

416

Adaptations to high-intensity intermittent exercise in rodents  

PubMed Central

In humans, exercise-induced plasma volume (PV) expansion is typically associated with an increase in plasma albumin content, due in part to an increase in hepatic albumin synthesis. We tested the ability of a 12-day high-intensity intermittent exercise protocol to induce an increase in PV in rodents. Since albumin synthesis is transcriptionally regulated, we tested the hypothesis that exercise training would induce an increase in hepatic albumin gene expression. Fifty adult male Sprague-Dawley rats weighing between 245 and 350 g were randomly assigned to one of five groups: cage control (CC), sham exercise (sham), continuous moderate-intensity exercise training (MI), high-intensity intermittent exercise training (HI), or a single day of HI training (1-HI). Twenty-four hours after the last training session, rats were anesthetized. PV was determined, and the liver was removed, flash frozen, and stored for later analysis. Citrate synthase (CS) activity of the red quadriceps muscle, a marker of aerobic adaptation, increased with training (MI and HI) and in response to 1-HI (P < 0.05). We did not see a significant exercise-induced PV expansion as PV averaged 23.6 ± 2.7 ml/kg body wt in the CC group and 26.6 ± 1.3 ml/kg body wt in the HI group (P > 0.05). However, hepatic albumin mRNA expression, as determined by real-time PCR, increased 2.9 ± 0.4- and 4.1 ± 0.4-fold after MI and HI, respectively, compared with CC. A single bout of HI (1-HI) did not alter hepatic albumin mRNA expression. These data demonstrate an increase in both CS activity and hepatic albumin gene expression with 12 days of aerobic exercise training in the rodent with a rapid (within 24 h) adaptation in the skeletal muscle to high-intensity intermittent exercise.

Bexfield, Nathan A.; Parcell, Allen C.; Nelson, W. Bradley; Foote, Kristopher M.; Mack, Gary W.

2009-01-01

417

Recent Pacific Northwest Laboratory beagle and rodent studies  

SciTech Connect

Analyses based on data from two experimental studies conducted at Pacific Northwest Laboratory will be presented. The first is a lifespan study of beagle dogs exposed to inhaled plutonium. The objectives of this study are, first, to determine the biological effects in dogs of inhaled plutonium at various dose levels, and, second, to obtain dose-effect relationship data that can be used to estimate the risk of these effects in humans. In this study, eighteen-month-old beagle dogs were exposed through inhalation to six different levels and three different types of plutonium. The lowest level corresponds to the maximum permissible level for a plutonium worker, while the highest level is a level at which radiation pneumonitis is likely to cause early death. {sup 239}PuO{sub 2} was chosen because it is the form of plutonium to which people working in nuclear fuel processing and storage industries are likely to be exposed. {sup 238}PuO{sub 2} and {sup 239}Pu(NO{sub 3}){sub 4} were chosen because they result in different spatial and temporal distribution of radiation dose, and thus can provide information on the influence of these factors on risk. The second experiment is a lifespan study of rodents exposed through inhalation to radon and radon progeny. For the rodent experiments to be considered in this presentation, exposures were initiated at about 90 days of age at rates of 5, 50, and 500 WLM per week. Cumulative exposure levels were 320, 640, 1280, 2560, and 5120 WLM for animals exposed at 50 and 500 WLM per week, and 320 WLM for animals exposed at 5 WLM per week. 7 refs.

Gilbert, E.S.; Park, J.F.; Cross, F.C.; Dagle, G.E.

1990-07-01

418

Baculoviral expression and characterization of rodent cathepsin S.  

PubMed

The cysteinyl proteinase cathepsin S is implicated as a key enzyme in the processing of major histocompatability complex (MHC) class II molecules expressed on antigen presenting cells and thus is a potential therapeutic target for modulation in immune system-based disease. We have identified a form of rat cathepsin S, similar to a published mouse form with an eight-amino acid extended presequence relative to the human enzyme and the previously published rat enzyme. In addition, we have expressed these mouse and rat proteins in baculovirally infected Sf9 insect cells along with "humanized" forms truncated by eight residues at the amino-terminus. All forms of the rodent proteinases were overexpressed and milligram per litre amounts of functional enzyme could be isolated from the cells and/or the cell culture supernatant. Furthermore, addition of a carboxy-terminal hexahistidine purification tag had no effect on the kinetic characteristics of any of the enzyme forms against the Boc-Val-Leu-Lys-AMC peptide substrate (rat k(cat) s(-1) approximately 30; mouse k(cat) s(-1) approximately 65). Differences were seen in the potency of the generic cysteine proteinase inhibitor, E64, against the human, mouse, or rat form of the enzyme (13.3 x 10(4), 43.2 x 10(4), and 25 x 10(4) K(obe)/[I] M(-1) s(-1), respectively). Such data highlights the need for greater awareness of species variation in inhibitor potency. These reagents are vital for confirming inhibitor potency against the endogenous form of the enzyme prior to evaluation of drug candidates in rodent model systems. PMID:11570845

Mason, C S; Lamers, M B; Henderson, I M; Monk, T; Williams, D H

2001-10-01

419

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

420

Discovery of a cytosolic/soluble ferroxidase in rodent enterocytes  

PubMed Central

Hephaestin (Heph), a membrane-bound multicopper ferroxidase (FOX) expressed in duodenal enterocytes, is required for optimal iron absorption. However, sex-linked anemia (sla) mice harboring a 194-amino acid deletion in the Heph protein are able to absorb dietary iron despite reduced expression and mislocalization of the mutant protein. Thus Heph may not be essential, and mice are able to compensate for the loss of its activity. The current studies were undertaken to search for undiscovered FOXs in rodent enterocytes. An experimental approach was developed to investigate intestinal FOXs in which separate membrane and cytosolic fractions were prepared and FOX activity was measured by a spectrophotometric transferrin-coupled assay. Unexpectedly, FOX activity was noted in membrane and cytosolic fractions of rat enterocytes. Different experimental approaches demonstrated that cytosolic FOX activity was not caused by contamination with membrane Heph or a method-induced artifact. Cytosolic FOX activity was abolished by SDS and heat (78 °C), suggesting protein-mediated iron oxidation, and was also sensitive to Triton X-100. Furthermore, cytosolic FOX activity increased ?30% in iron-deficient rats (compared with controls) but was unchanged in copper-deficient rats (in contrast to the reported dramatic reduction of Heph expression and activity during copper deficiency). Additional studies done in sla, Heph-knockout, and ceruloplasmin-knockout mice proved that cytosolic FOX activity could not be fully explained by Heph or ceruloplasmin. Therefore rodent enterocytes contain a previously undescribed soluble cytosolic FOX that may function in transepithelial iron transport and complement membrane-bound Heph.

Ranganathan, Perungavur N.; Lu, Yan; Fuqua, Brie K.; Collins, James F.

2012-01-01

421

Rain on small tropical islands  

NASA Astrophysics Data System (ADS)

A high-resolution rainfall climatology based on observations from the Tropical Rainfall Measuring Mission's Precipitation Radar (PR) instrument is used to evaluate the influence of small tropical islands on climatological rainfall. Islands with areas between one hundred and several thousand km2 are considered in both the Indo-Pacific Maritime Continent and Caribbean regions. Annual mean climatological (1997-2007) rainfall over each island is compared with that over the surrounding ocean region, and the difference is expressed as a percentage. In addition to total rainfall, rain frequency and intensity are also analyzed. Results are stratified into two 12 h halves of the diurnal cycle as well as eight 3 h periods, and also by a measure of each island's topographic relief. In both regions, there is a clear difference between larger islands (areas of a few hundred km2 or greater) and smaller ones. Both rain frequency and total rainfall are significantly enhanced over larger islands compared to the surrounding ocean. For smaller islands the enhancement is either negligibly small, statistically insignificant, or, in the case of Caribbean rain frequency, negative. The enhancement in total rainfall over larger islands is partly attributable to greater frequency and partly to greater intensity. A diurnal cycle in island enhancement is evident in frequency but not intensity, except over small Caribbean islands where the converse is true. For the larger islands, higher orography is associated with greater rainfall enhancements. The orographic effect is larger (percentagewise) in the Caribbean than in the Maritime Continent. Orographic precipitation enhancement manifests more strongly as increased frequency of precipitation rather than increased intensity and is present at night as well as during the day. The lack of a clear diurnal cycle in orographic enhancement suggests that much of the orographic rainfall enhancement is attributable to mechanically forced upslope flow rather than elevated surface heating.

Sobel, A. H.; Burleyson, C. D.; Yuter, S. E.

2011-04-01

422

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

423

Typing of Brachyspira spp. from rodents, pigs and chickens on Swedish farms.  

PubMed

The aim of the current study was to look for evidence of possible cross-species transmission of Brachyspira species between rodents and farm animals. To do this, previously collected and characterised Brachyspira isolates from rodents, pigs and chickens on the same farms were analysed by random amplified polymorphic DNA (RAPD). Isolates with similar RAPD banding patterns were further typed by pulsed-field gel electrophoresis (PFGE). Identical isolates of Brachyspira pilosicoli, Brachyspira intermedia, Brachyspira murdochii and Brachyspira innocens from pigs and rodents and of B. murdochii from laying hens and rodents were found, indicating cross-species transmission at farm level. PFGE data from rodent isolates of Brachyspira hyodysenteriae were compared with PFGE data from previously typed field isolates of B. hyodysenteriae from pigs with swine dysentery and isolates from mallards (Anas platyrhynchos). Three of four isolates of B. hyodysenteriae from rodents were similar to porcine field isolates by PFGE. PCR analyses of the plasmid-encoded and potential virulence determinants rfb genes B, A, D and C showed that they were present in isolates of B. hyodysenteriae of porcine, mallard and rodent origin. PMID:21497461

Backhans, A; Jansson, D S; Aspán, A; Fellström, C

2011-03-26

424

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

425

Seasonal Variation of Tropical Humidity Parameters.  

National Technical Information Service (NTIS)

The study deals with the zonal average monthly variations in humidity, horizontal vapor transfer, vertically integrated flux divergence, and water balance of the total atmospheric column in the tropics. The author brings out the broad-scale features of th...

E. M. Rasmusson

1972-01-01

426

Tropical Rainforest Silviculture: A Research Project Report.  

National Technical Information Service (NTIS)

This report describes the results of a research project concerned with silviculture and management of tropical rainforest. Data from silvicultural treatment experiments were analyzed to examine the effects of logging and treatments on growth rates and yie...

T. J. Synnott

1981-01-01

427

Communications Cable for Tropical Jungle Use.  

National Technical Information Service (NTIS)

Phase III upgrading of the Phase II communications cable for arctic, temperate, and tropical environments began with the screening of Phase II materials for serviceability at low temperature. A test was devised to simulate field handling at low temperatur...

J. H. Gesell C. E. Kazimer C. F. Engler I. T. Stoneback

1965-01-01

428

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

2006-09-29

429

Infective Causes of Stroke in Tropical Regions  

PubMed Central

Vascular diseases of the brain are the second reason of the death and the first cause of morbidity and disability worldwide. In tropical areas stroke has some particular features related to the nature of torrid zones. There are some special causes of the stroke, mainly infectious, although some of them are non-infectious. The most important etiologies are malaria, tuberculosis, cysticercosis, syphilis, and Chagas’ disease. The mean age of the patients with stroke in tropical areas seems to be less than that in developed countries, and the disease is more prevalent in younger adults. Prevention and/or treatment of the classic risk factors as well as factors related to tropical zones are the mainstays of controlling the disease. It has to be mentioned that lack of human as well as financial resources makes it difficult to control and treat the disease properly. Herein, the etiologies and risk factors of the cerebrovascular diseases in tropical regions will be reviewd.

Moghtaderi, Ali; Alavi-Naini, Roya

2012-01-01

430

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.

431

Global change integrating factors: Tropical tropopause trends.  

National Technical Information Service (NTIS)

This research proposes new criteria, shifts in the height and temperature of the tropical tropopause, as measures of global climate change. The search for signs of global warming in the temperature signal near the earth's surface is extremely difficult, l...

R. A. Reck

1994-01-01

432

Trade, tropical deforestation and policy interventions.  

National Technical Information Service (NTIS)

This paper examines several aspects of the links between the trade in tropical timber and deforestation from the perspective of an exporting country. The various versions of the model developed here have highlighted a number of important features of this ...

E. B. Barbier M. Rauscher

1992-01-01

433

Tropical Cyclones, Sea Surface Temperature, and Beyond  

NSDL National Science Digital Library

Part 1 The SAGUARO Exploring GIS Investigations for Earth Science curriculum requries the use of ESRI's ArcViewà GIS software version 3.0 for Macintosh or 3.2 and higher for PC. Use ArcGIS and data files from the SAGUARO Project's (http://www.scieds.com/saguaro/etc.html) Exploring Tropical Cyclones investigations. After the students are introduced to the program they are asked to determine what criteria are required for the formation of tropical cyclones. Exploring Tropical Cyclones Unit 1 has a great deal of data for the students to use. The data is presented as layers on a world map. Different features can be turned on and off at will, and layers can be brought in from other units if desired. Features they can work with are: August SST February SST tropical cyclone tracks locations of tropical cyclone formation for Jun-Sep locations of tropical cyclone formation for Dec-Mar Part 2 Students are divided into small groups (3-4 students works well) where they compare their findings (including what evidence they used) with the findings of the other group members. Each group is then asked to determine the threshold temperature for tropical cyclone formation as well as to calculate the area of the ocean that has SST equal to or above this threshold temperature (you can have them calculate this for each season, or as a total area including both February and August data). Part 3 Class discussion of what they have found so far. Introduce them to model predictions of SST for different atmospheric CO2 levels. Propose a 2 degree C increase in tropical SST and ask what they think that will mean. What other factors might influence the formation of tropical cyclones? Part 4 Assign an article or two (ideally a published peer reviewed article - to introduce them to this type of scientific writing - that is if you can find one that you consider appropriate for your students) that introduces them to other factors required for tropical cyclone formation and predictions of how climate change might affect them. For example an article that discusses the role of wind speed near the surface of the ocean, or vertical wind shear, or one that shows that the threshold temperature is actually predicted to increase by the same magnitude as the SST increase. Have them write a report that summaries the criteria for cyclogenesis as well as explaining how they would go about predicting where tropical cyclones will form as a result of an increased SST. They do not need to perform all of the tests they propose! They should state what sort of information they would like to obtain and why.

Schmitt, Danielle

434

Tropical forests and atmospheric carbon dioxide.  

PubMed

Tropical forests play a major role in determining the current atmospheric concentration of CO2, as both sources of CO2 following deforestation and sinks of CO2 probably resulting from CO2 stimulation of forest photosynthesis. Recently, researchers have tried to quantify this role. The results suggest that both the carbon sources and sinks in tropical forests are significantly greater than previously thought. PMID:10884705

Malhi; Grace

2000-08-01

435

Conservation of tropical birds: mission possible?  

Microsoft Academic Search

Worldwide habitat loss, fragmentation, and degradation are operating on a massive scale—and are accelerating. Many scientific\\u000a studies have shown or predicted that such habitat destruction will have dire consequences for the future of global biodiversity.\\u000a Habitat loss in the tropics especially is unprecedented, which is of particular concern because the tropics have the greatest\\u000a diversity and are centers of endemism.

Navjot S. Sodhi; Kimberly G. Smith

2007-01-01

436

Southeast Asian tropical medicine and parasitology network  

Microsoft Academic Search

The SEAMEO TROPMED Network is a regional cooperative network established in 1967 for education, training and research in tropical medicine and public health under the Southeast Asia Ministers of Education Organization. The Network operates through four Regional Centers with respective areas of specialization and host institutions: Community Nutrition\\/Tropmed Indonesia; Microbiology, Parasitology and Entomology\\/Tropmed Malaysia; Public Health\\/Tropmed Philippines; and Tropical Medicine\\/Tropmed

Jitra Waikagul

2006-01-01

437

Genetic aspects of tropical calcific pancreatitis  

Microsoft Academic Search

Tropical calcific pancreatitis (TCP) is a subtype of chronic pancreatitis which is unique to tropical regions. Patients present\\u000a at young age with recurrent abdominal pain, nutritional deficiencies, and insulin-requiring diabetes. For a long time, the\\u000a aetiology of this disorder was poorly understood. Several environmental factors, such as malnutrition or the consumption of\\u000a toxic food components such as cyanogenic glycosides, were

Heiko Witt; Eesh Bhatia

2008-01-01

438

Dendroecology in the tropics: a review  

Microsoft Academic Search

Over the last decade the field of tropical dendroecology has developed rapidly and major achievements have been made. We reviewed\\u000a the advances in three main themes within the field. First, long chronologies for tropical tree species were constructed which\\u000a allowed climate reconstructions, revealed sources of climatic variation and clarified climate–growth relations. Other studies\\u000a combined tree-ring data and stable isotope (13C

Danaë M. A. Rozendaal; Pieter A. Zuidema

2011-01-01

439

Tropical Forest Healers and Habitat Preference  

Microsoft Academic Search

Tropical forests represent repositories of medicinal plant species and indigenous ethnomedical knowledge. These biotic and\\u000a cognitive resources are threatened by forest removal and culture change. It has, however, yet to be demonstrated quantitatively\\u000a that tropical pharmacopoeias are concentrated in primary as opposed to disturbed forests, nor that folk ethnomedical knowledge\\u000a is disappearing. I examined these questions by means of a

R. A. Voeks

1996-01-01

440

Carbon Exchange Among Tropical Coastal Ecosystems  

Microsoft Academic Search

Tropical rivers provide about 60% of the global transport of organic and inorganic carbon from continents to the coastal zone.\\u000a These inputs combine with organic material from productive mangrove forests, seagrass beds, and coral reefs to make tropical\\u000a coastal ecosystems important components in the global carbon cycle. Carbon exchange has been measured over multiple spatial\\u000a scales, ranging from the transport

Steven Bouillon; Rod M. Connolly

2009-01-01

441

Shade Tolerance of Tropical Forages: A Review  

Microsoft Academic Search

The paper reviews the shade tolerance of tropical forages and discusses the adaptation of species to low light. Shading reduces tiller production and leaf, stem, stubble and root yield but increases specific leaf area and shoot\\/root and leaf\\/stem ratios, particularly in shade-tolerant species. Yield responses of many tropical forages to shading reflected the strong relationship between productivity and irradiance, but

C. C. Wong

442

Characterization of clouds in Titan's tropical atmosphere  

USGS Publications Warehouse

Images of Titan's clouds, possible over the past 10 years, indicate primarily discrete convective methane clouds near the south and north poles and an immense stratiform cloud, likely composed of ethane, around the north pole. Here we present spectral images from Cassini's Visual Mapping Infrared Spectrometer that reveal the increasing presence of clouds in Titan's tropical atmosphere. Radiative transfer analyses indicate similarities between summer polar and tropical methane clouds. Like their southern counterparts, tropical clouds consist of particles exceeding 5 ??m. They display discrete structures suggestive of convective cumuli. They prevail at a specific latitude band between 8??-20?? S, indicative of a circulation origin and the beginning of a circulation turnover. Yet, unlike the high latitude clouds that often reach 45 km altitude, these discrete tropical clouds, so far, remain capped to altitudes below 26 km. Such low convective clouds are consistent with the highly stable atmospheric conditions measured at the Huygens landing site. Their characteristics suggest that Titan's tropical atmosphere has a dry climate unlike the south polar atmosphere, and despite the numerous washes that carve the tropical landscape. ?? 2009. The American Astronomical Society.

Griffith, C. A.; Penteado, P.; Rodriguez, S.; Le, Mouelic, S.; Baines, K. H.; Buratti, B.; Clark, R.; Nicholson, P.; Jaumann, R.; Sotin, C.

2009-01-01

443

CHARACTERIZATION OF CLOUDS IN TITAN'S TROPICAL ATMOSPHERE  

SciTech Connect

Images of Titan's clouds, possible over the past 10 years, indicate primarily discrete convective methane clouds near the south and north poles and an immense stratiform cloud, likely composed of ethane, around the north pole. Here we present spectral images from Cassini's Visual Mapping Infrared Spectrometer that reveal the increasing presence of clouds in Titan's tropical atmosphere. Radiative transfer analyses indicate similarities between summer polar and tropical methane clouds. Like their southern counterparts, tropical clouds consist of particles exceeding 5 {mu}m. They display discrete structures suggestive of convective cumuli. They prevail at a specific latitude band between 8 deg. - 20 deg. S, indicative of a circulation origin and the beginning of a circulation turnover. Yet, unlike the high latitude clouds that often reach 45 km altitude, these discrete tropical clouds, so far, remain capped to altitudes below 26 km. Such low convective clouds are consistent with the highly stable atmospheric conditions measured at the Huygens landing site. Their characteristics suggest that Titan's tropical atmosphere has a dry climate unlike the south polar atmosphere, and despite the numerous washes that carve the tropical landscape.

Griffith, Caitlin A.; Penteado, Paulo [Department of Planetary Sciences, University of Arizona, Tucson, AZ 85719 (United States); Rodriguez, Sebastien [Laboratoire AIM, Universite Paris 7/CNRS/CEA-Saclay, DSM/IRFU/SAp (France); Le Mouelic, Stephane [Laboratoire de Planetologie et Geodynamique, CNRS, UMR-6112, Universite de Nantes, 44000 Nantes (France); Baines, Kevin H.; Buratti, Bonnie; Sotin, Christophe [Jet Propulsion Laboratory, Pasadena, CA 91109 (United States); Clark, Roger [U.S. Geological Survey, Denver, CO 80225 (United States); Nicholson, Phil [Department of Astronomy, Cornell University, Ithaca, NY (United States); Jaumann, Ralf [Institute of Planetary Exploration, Deutsche Zentrum, fuer Luft- und Raumfahrt (Germany)

2009-09-10

444

Predicting soil properties in the tropics  

NASA Astrophysics Data System (ADS)

It is practically impossible to measure soil properties continuously at each location across the globe. Therefore, it is necessary to have robust systems that can predict soil properties at a given location. That is needed in many tropical countries where the dearth of soil property measurements is large. This paper reviews the use of pedotransfer functions (PTF) for predicting properties of soils in the tropics. First, the guiding principles of prediction and the type of predictors are discussed, including laboratory data, field description and soil morphology, electromagnetic spectrum, proximal and remote sensed data. In the subsequent section, PTFs are discussed for soil physical and chemical properties followed by infrared spectroscopy, proximal sensing and remote sensing. An analysis of ISRIC (mainly tropical) and USDA (mainly temperate) soil databases showed that soils in the tropics have higher clay content, lower cation exchange capacity, higher bulk density, lower water content at - 10 kPa and - 1500 kPa than soils in the temperate regions. Various methods developed in temperate regions can be applied for the soils in the tropical regions although calibration and careful selection of predictors remains necessary. It is concluded that PTFs are an important tool to overcome the dearth of soil data in many tropical countries.

Minasny, Budiman; Hartemink, Alfred E.

2011-05-01

445

Anti-dementia drugs and hippocampal-dependent memory in rodents  

PubMed Central

Abnormalities in hippocampal structure and function are characteristics of early Alzheimer's disease (AD). Behavioral tests measuring hippocampal-dependent memory in rodents are often used to evaluate novel treatments for AD and other dementias. In this study, we review the effects of drugs marketed for the treatment of AD, such as the acetylcholinesterase inhibitors, donepezil, rivastigmine, galantamine and the N-methyl-d-aspartic acid antagonist, memantine, in rodent models of memory impairment. We also briefly describe the effects of novel treatments for cognitive impairment in rodent models of memory impairment, and discuss issues concerning the selection of the animal model and behavioral tests. Suggestions for future research are offered.

Yuede, Carla M.; Dong, Hongxin; Csernansky, John G.

2009-01-01

446

Pathology of rodent models of intestinal cancer: progress report and recommendations.  

PubMed

In October 2010, a pathology review of rodent models of intestinal neoplasia was held at The Jackson Laboratory. This review complemented 2 other concurrent events: a workshop on methods of modeling colon cancer in rodents and a conference on current issues in murine and human colon cancer. We summarize the results of the pathology review and the committee's recommendations for tumor nomenclature. A virtual high-resolution image slide box of these models has been developed. This report discusses significant recent developments in rodent modeling of intestinal neoplasia, including the role of stem cells in cancer and the creation of models of metastatic intestinal cancer. PMID:23415801

Washington, Mary Kay; Powell, Anne E; Sullivan, Ruth; Sundberg, John P; Wright, Nicholas; Coffey, Robert J; Dove, William F

2013-02-12

447

How can tropical cyclones survive?  

NASA Astrophysics Data System (ADS)

How can tropical cyclones survive? It is important for understanding the development of tropical cyclones to be able to quantify the exchange of enthalpy and momentum between air and water. Air-sea fluxes are often formulated as drag CD and enthalpy CK exchange coefficients. Emanuel, 1986, derived an expression for potential intensity that depends on local environment parameters and is proportional to the ratio of enthalpy and drag coefficients. This ratio should be larger than 0.75 for a cyclone to develop. There are no direct surface measurements of CK/ CD under hurricane conditions and extrapolation from most open-ocean measurements at 25 m/s gives values of CK/ CD< 0.75 and in that case no cyclone could survive and Emanuel's theory must be wrong. However there are measurements of CK taken over the Baltic Sea and Lake Ontario showing increasing values of CK up to 2.5 for wind speeds around 12 m/s. If this can be implemented for hurricane conditions the ratio CK/ CD>0.75 is in accordance with Emanuel's prediction. The high CK values are observed during situations when there is a regime shift of the structure of turbulence in the boundary layer. From spectral analysis it was found that as the boundary layer approaches neutral stratification, smaller-scale eddies become increasingly important in the turbulent transport of humidity and sensible heat and thus enhance the exchange coefficient CK. This turbulence regime is called the UVCN regime and require high wind speed, small temperature difference between air and water, sufficiently strong wind gradients and growing sea condition ( Smedman et al., 2007, Sahlee et al., 2008). What is the difference between world oceans and enclosed seas? The answer is the waves. The wave field over the open oceans is swell dominated but in enclosed seas and coastal areas swell is restricted mainly to low wind speed conditions, and swell is short lived because of short distances to the shores. When swell is present the MABL will be dominated by large eddies of zi size creating weak gradients of wind, temperature and humidity and thus small scale eddies cannot be formed leading to reduced CK-values. However, during hurricane condition the waves are expected to be young, stratification is close to neutral and gradients are sufficiently large to generate UVCN condition and thus increased CK values. References: K. A. Emanuel, 1986: An air-sea interaction theory for tropical cyclones, part I: Steady-state maintenance, J. Atmos. Sci., 43,585-604 E. Sahlee et al., 2008: Reevaluation of bulk exchange coefficient for humiditu at sea during unstable and neutral conditions, DOI:10.1175/2007JPO3754.1 A. Smedman, 2007: Heat/mass transfer in the slightly unstable atmospheric surface layer,Quart. J. Meteorol. Soc., 133, 37-51

Smedman, Ann-Sofi

2013-04-01

448

Tropical Cyclone Report: Tropical Storm Jerry (AL112007), September 23-24, 2007.  

National Technical Information Service (NTIS)

Jerry was a short-lived tropical cyclone over the far northeastern Atlantic. A non-tropical low formed in the central North Atlantic on 21 September and meandered for a few days, while gradually developing deep convection. The thunderstorm activity became...

L. A. Avila

2007-01-01

449

On the Transformation of a Tropical Easterly Wave into a Tropical Depression: A Simple Numerical Study  

Microsoft Academic Search

Through the time integration of a simple numerical model, the transfomation of a tropical easterly wave into a tropical depression was investigated. The initial condition selected for the model is a slowly decaying adiabatic linear normal mode resembling an easterly wave. It was found that the addition of a CISK (conditional instability of the second kind) type heating effect to

Yoshio Kurihara; Mitsuhiro Kawase

1985-01-01

450

Pacific Exploratory Mission in the tropical Pacific: PEM-Tropics A, August–September 1996  

Microsoft Academic Search

Abstract. The NASA Pacific Exploratory Mission to the Pacific tropics (PEM-Tropics) is the third major field campaign of NASA' s Global Tropospheric Experiment (GTE) to study the impact of human and natural processes on the chemistry of the troposphere over the Pacific basin. The first two campaigns, PEM-West A and B were conducted over the northwestern regions of the Pacific

J. M. Hoell; D. D. Davis; D. J. Jacob; M. O. Rodgers; R. E. Newell; H. E. Fuelberg; R. J. McNeal; J. L. Raper; R. J. Bendura

1999-01-01

451

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

452

Habituation and Prepulse Inhibition of Acoustic Startle in Rodents  

PubMed Central

The acoustic startle response is a protective response, elicited by a sudden and intense acoustic stimulus. Facial and skeletal muscles are activated within a few milliseconds, leading to a whole body flinch in rodents1. Although startle responses are reflexive responses that can be reliably elicited, they are not stereotypic. They can be modulated by emotions such as fear (fear potentiated startle) and joy (joy attenuated startle), by non-associative learning processes such as habituation and sensitization, and by other sensory stimuli through sensory gating processes (prepulse inhibition), turning startle responses into an excellent tool for assessing emotions, learning, and sensory gating, for review see 2, 3. The primary pathway mediating startle responses is very short and well described, qualifying startle also as an excellent model for studying the underlying mechanisms for behavioural plasticity on a cellular/molecular level3. We here describe a method for assessing short-term habituation, long-term habituation and prepulse inhibition of acoustic startle responses in rodents. Habituation describes the decrease of the startle response magnitude upon repeated presentation of the same stimulus. Habituation within a testing session is called short-term habituation (STH) and is reversible upon a period of several minutes without stimulation. Habituation between testing sessions is called long-term habituation (LTH)4. Habituation is stimulus specific5. Prepulse inhibition is the attenuation of a startle response by a preceding non-startling sensory stimulus6. The interval between prepulse and startle stimulus can vary from 6 to up to 2000 ms. The prepulse can be any modality, however, acoustic prepulses are the most commonly used. Habituation is a form of non-associative learning. It can also be viewed as a form of sensory filtering, since it reduces the organisms' response to a non-threatening stimulus. Prepulse inhibition (PPI) was originally developed in human neuropsychiatric research as an operational measure for sensory gating7. PPI deficits may represent the interface of "psychosis and cognition" as they seem to predict cognitive impairment8-10. Both habituation and PPI are disrupted in patients suffering from schizophrenia11, and PPI disruptions have shown to be, at least in some cases, amenable to treatment with mostly atypical antipsychotics12, 13. However, other mental and neurodegenerative diseases are also accompanied by disruption in habituation and/or PPI, such as autism spectrum disorders (slower habituation), obsessive compulsive disorder, Tourette's syndrome, Huntington's disease, Parkinson's disease, and Alzheimer's Disease (PPI)11, 14, 15 Dopamine induced PPI deficits are a commonly used animal model for the screening of antipsychotic drugs16, but PPI deficits can also be induced by many other psychomimetic drugs, environmental modifications and surgical procedures.

Valsamis, Bridget; Schmid, Susanne

2011-01-01

453

An in vitro model of rodent nongenotoxic hepatocarcinogenesis.  

PubMed

An in vitro model of liver in which rat hepatocytes are maintained as cocultures with nonparenchymal epithelial cells (NPC) derived from liver has been developed and characterized with respect to maintenance of hepatocyte viability and differentiated function. The system was then evaluated as a model for studying peroxisome proliferator-induced rodent liver nongenotoxic carcinogenesis. Within the coculture model, hepatocyte viability and morphology were maintained for 1 month or more within a system that is both easily accessible for microscopic examination and is free of any additives that may lead to artifacts. Even after 1 month or more, hepatocyte cocultures retained expression of the constitutive liver marker albumin. In addition, they maintained the ability to show induction of the peroxisome proliferator-inducible enzymes peroxisomal bifunctional enzyme (PBE) and cytochrome P450IVA1 in response to the peroxisome proliferator nafenopin. After 4 weeks, NPC cocultures showed a six- and a fourfold induction of PBE and cytochrome P450IVA1 expression, respectively, which compared well with the three- and fivefold induction seen in freshly isolated cells. This was paralleled by an increase in the cytoplasmic volume fraction of peroxisomes averaging eightfold. Interestingly, great heterogeneity was exhibited between adjacent hepatocytes in terms of the degree of peroxisome proliferation, a finding reflected by immunocytochemical staining which indicated heterogeneity in the level of expression of the peroxisome proliferator-inducible enzymes. Other cell lines representing different tissue types, morphologies, and species were also examined for their ability to support hepatocyte survival but were found to be ineffective, with the exception of a bovine corneal endothelial cell line. This line supported hepatocyte survival and maintenance of differentiated function but to a lesser extent than that observed with NPC. Ultrastructural examination of NPC cocultures revealed extensive interhepatocyte junctional complexes and interdigitation of adjacent membranes together with the presence of bile canalicular structures. There were no junctional complexes between the hepatocytes and the supporting feeder cells with any contact being limited to a close association of the hepatocytes with the extracellular matrix presumably produced by the NPC. The data demonstrate that hepatocytes maintained in vitro within an NPC coculture system retain differentiated function and the ability to respond to the peroxisome proliferator class of nongenotoxic carcinogens. Cocultures will provide us with a model system for the study of changes in hepatocyte growth regulation during rodent liver nongenotoxic carcinogenesis. PMID:1281111

James, N H; Molloy, C A; Soames, A R; French, N J; Roberts, R A

1992-12-01

454

Tropical spastic paraparesis in Kerala.  

PubMed

Tropical Spastic Paraparesis (TSP) is an uncommon myeloneuropathy with an insular geographic distribution. In 1985, Human T-lymphotropic virus type I (HTLV-1) was reported to be a possible etiological factor. We did an epidemiological, clinical and virological study of 25 cases of TSP. They were predominantly young adult men, whose duration of illness ranged from 6 months to 15 years. Difficulty in walking, stiffness of legs and paraesthesia of legs were the main symptoms. None had tuberculosis, syphilis, malnutrition or lathyrism. Pyramidal signs of the lower limbs, upper limbs, posterior column involvement and spinothalamic tract dysfunction were the common signs. Laboratory findings and cerebrospinal fluid analysis were normal in most. Myelograms or MRI were normal in all. Only 1 case repeatedly tested positive for HTLV-1 antibodies. None of his relatives had clinical or virological evidence of TSP or HTLV-1 infection. Based on our study, we could not link HTLV-I infection to TSP in Indian cases. Virological testing for HTLV-I infection by polymerase chain reaction may be a better tool to reveal such an association. Our cases were similar to seronegative spinal spastic paraplegia. A related new retrovirus or an altered immune response to HTLV-1 due to environmental or dietary factors are possibilities which require further exploration. PMID:14742930

Oomman, A; Madhusoodanan, M

2003-12-01

455

Teaching ultrasound in tropical countries  

PubMed Central

Introduction This paper reports my experience as a teacher of clinical ultrasound (US) in an African hospital. While US in tropical countries has received some attention and a few papers – though possibly fewer than deserved by this issue-are available in the medical literature on this subject, very little has been done in terms of assessment of teaching. Materials and methods Given the increasing number of groups, NGOs and volunteers that go to Africa and other resource limited settings to do this, I thought that sharing my experience with those who have walked or are thinking of walking the same path could be mutually beneficial. Results The first section of the article presents the situation where I've been working in the past 13 years, the second section details our teaching programme. Discussion This report describes the rationale for the implementation of ultrasound training programmes in rural areas of Africa and lessons learnt with 13 years experience from the UK with recommendations for the way forward.

Conlon, R.

2012-01-01

456

Tropical infections in the ICU.  

PubMed

Certain arthropod-borne infections are common in tropical regions because of favorable climatic conditions. Water-borne infections like leptospirosis are common due to contamination of water especially during the monsoon floods. Infections like malaria, leptospirosis, dengue fever and typhus sometimes cause life threatening organ dysfunction and have several overlapping features. Most patients present with classicial clinical syndromes: fever and thrombocytopenia are common in dengue, malaria and leptospirosis; coagulopathy is frequent in leptospirosis and viral hepatitis. Hepatorenal syndrome is seen in leptospirosis, falciparum malaria and scrub typhus. The pulmonary renal syndrome is caused by falciparium malaria, leptospirosis, Hantavirus infection and scrub typhus. Fever with altered mental status is produced by bacterial meningitis, Japanese B encephalitis, cerebral malarial, typhoid encephalopathy and fulminant hepatic failure due to viral hepatitis. Subtle differences in features of the organ failure exist among these infections. The diagnosis in some of these diseases is made by demonstration of antibodies in serum, and these may be negative in the first week of the illness. Hence empiric therapy for more than one disorder may be justified in a small proportion of cases. In addition to specific anti-infective therapy, management of organ dysfunction includes use of mechanical ventilation, vasopressor drugs, continuous renal replacement therapy and blood products. Timely transfer of these patients to well-equipped ICUs with experience in managing these cases can considerably decrease mortality and morbidity. PMID:16944613

Kothari, Vatsal M; Karnad, Dilip R; Bichile, Lata S

2006-04-01

457

Analysis of protein pool of neuronal populations of cerebellar cortex in rodents of different species.  

PubMed

The protein pool of neuronal population of the cerebellar cortex was studied by interference cytometry in rodents occupying different ecological niches and differing by life style, nutrition habits, and motor activity. In all cell populations protein concentrations in the cytoplasm were higher than in the nucleus in all studied rodents and did not depend on the functional characteristics of neurons. The extreme values of protein content were determined for populations of granular and ganglion cells. High protein concentrations per volume unit of cell structure were detected in functionally different cerebellar neurons of gray rats, characterized by high motor activity and a certain degree of synanthropy, while low values were detected in mole rats, slow-moving underground rodents. Therefore, the specific protein pool of neuronal populations of the cerebellar cortex of rodents can be regarded as adaptation to habitation conditions. PMID:11276318

Orlyanskaya, T Y; Lyutikova, T M

2000-12-01

458

Iron Chelators: In vitro Inhibitory Effect on the Liver Stage of Rodent and Human Malaria.  

National Technical Information Service (NTIS)

The activity of desferrioxamine (Desferal) and desferrithiocin (a newly developed oral iron chelator) was evaluated against the liver stage of Plasmodium yoelii and P. falciparum in the rodent and the human hepatocyte in vitro culture system. The two iron...

E. Stahel D. Nazier A. Guillouzo F. Miltgen I. Landau

1988-01-01

459

Role of Dopamine in Normal Rodent Motor Cortex: Physiological Effects and Structural Correlates.  

National Technical Information Service (NTIS)

Dopamine (DA) has been implicated in the cortical pathophysiology of several neurological disorders. Until recently, motor areas of the neocortex were thought to receive only sparse DA innervation. It is now known that the motor cortex of rodents and prim...

P. W. Awenowicz

1999-01-01

460

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

461

Environmental Enrichment of Laboratory Rodents: The Answer Depends on the Question.  

National Technical Information Service (NTIS)

Efforts to refine the care and use of animals in research have been ongoing for many years and have led to general standardization of rodent models, particularly with regard to animal housing, genetics, and health status. Concurrently, numerous informal p...

K. Kregel L. Leon L. A. Toth T. I. Musch

2011-01-01

462

Reservoir Competence of Various Rodents for the Lyme Disease Spirochete Borrelia spielmanii?  

PubMed Central

To determine whether the pathogenic Lyme disease spirochete Borrelia spielmanii is adapted exclusively to garden dormice, we compared the reservoir competence of various rodent species for this spirochete, including sympatric and peridomestic rodents. The different kinds of rodents varied in their attractiveness to nymphal ticks and their level of susceptibility to tick-borne B. spielmanii infection, but only the edible dormouse appeared to be refractory. Although hazel dormice and Norway rats became infectious to ticks somewhat later than did garden dormice, they remained infectious for a longer period of time. During the course of a tick season, garden and hazel dormice contributed theoretically more than twice as many B. spielmanii-infected ticks than the somewhat less susceptible Norway rats and wood or yellow-necked mice. Hazel dormice appeared to be extraordinarily competent as reservoir hosts for B. spielmanii. Because peridomestic rodents proved to be reservoir competent, urban foci of transmission of B. spielmanii may affect the health of townspeople.

Richter, Dania; Schlee, Daniela B.; Matuschka, Franz-Rainer

2011-01-01

463

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

464

Helminth parasite spectrum in rodent hosts from bamboo growing areas of Mizoram, North-east India.  

PubMed

In the northeastern state of Mizoram, India the rodent outbreak is periodic and coincides with bamboo (Melocanna baccifera) bloom causing a tremendous destruction to food crops that often results in famine. The present study was undertaken during the bamboo flowering period (2006-2008) to assess the parasite spectrum and load in the bourgeoning rodent population of the affected region. The survey results of the populations of 9 prevalent rodent species revealed that nematodes were the most dominant parasitic group followed by cestodes of the order Cyclophyllidea; however, the trematodes were found to be conspicuously missing. The nematodes harbored by the rodents belonged to the genera: Syphacia, Aspicularis, Trichuris, Rictularia, Capillaria, Trichosomoides, Nippostrongylus, Hepatojarakus and Heterakis, whereas the cestode genera included Hymenolepis, Raillietina and Taenia. Hymenolepis diminuta was the commonly encountered species. Only one acanthocephalan (Moniliformis sp.) could be collected during the entire study. PMID:23129885

Malsawmtluangi, C; Tandon, V

2010-02-27

465

Chemotherapy of Rodent Malaria (Annual Report, October 16, 1985-October 15, 1990).  

National Technical Information Service (NTIS)

In vivo studies in a rodent malaria model have confirmed that resistance to chloroquine is reversed by verapamil and also shown this effect with ketotifen and pizotyline. WR 238605 and desipramine had little activity. Penfluridol, cyproheptadine and ketot...