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1

Effect of intra-testicular melatonin injection on testicular functions, local and general immunity of a tropical rodent Funambulus pennanti  

Microsoft Academic Search

Local antigonadotrophic action of melatonin in testes has never been correlated with local and general immune status of any\\u000a rodent. Intra-testicular injection of melatonin (2.5 ?g\\/50 ?l) for 10 days (MI-10D) and 20 days (MI-20D) was given to young\\u000a adult male of Funambulus pennanti and testicular androgen receptor (AR), androgen binding protein (ABP) expression, 3?-hydroxysteroid dehydrogenase (3?-HSD)\\u000a activity, and Mel1aR expression in thymus was

Raise Ahmad; Chandana Haldar

2010-01-01

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

2013-09-01

3

Nycthemeral variation in melatonin receptor expression in the lymphoid organs of a tropical seasonal breeder Funambulus pennanti.  

PubMed

Seasonal variations in immune functions point toward the involvement of melatonin in its regulation. These chronobiotic effects are exerted by receptors present on the immunocompetent cells. The present study investigated daily/nycthemeral variation in expression of melatonin receptor subtypes MT1/MT2 in the lymphoid organs (spleen/thymus) of a tropical squirrel, Funambulus pennanti. The receptor expression was noted every 4 h interval over 24 h under natural light-dark cycle, during two seasons and was correlated with peripheral level of melatonin. The MT1/MT2 receptor expression displayed higher levels at the time of dusk (light-dark transition; 1800 hours), while plasma melatonin was still low compared to the preceding time point. The receptors were downregulated during the nighttime with a minimum expression at 0200 hours. Thymus, during the long day length, showed a tissue-specific pattern of receptor expression with a minimum expression at 0600 hours. Results suggest that photoperiod by modulation of melatonin level inversely regulates the receptor expression. The observations imply that there exists a temporal window of sensitivity in the target organs to the melatonin signal that is regulated by modulation of melatonin receptor expression which might be involved in mediating the photoperiodic effects of melatonin in the control of seasonal immune physiology. PMID:25369902

Gupta, Sameer; Haldar, Chandana

2014-12-01

4

Problems associated with the control of rodents in tropical Africa  

PubMed Central

As elsewhere in the world, rodents are responsible for very considerable economic losses in tropical Africa because of their depredations on both growing crops and stored food products. Unfortunately, few accurate data are available on the extent of these losses but there is evidence that they are considerable. The public health importance of rodents, both as reservoirs and vectors of disease in tropical Africa, is also great; plague, leptospirosis, murine typhus, and Lassa fever are among the diseases associated with rodent hosts. Scientifically based rodent control programmes have been carried out in very few areas of Africa and there is urgent need for studies and demonstrations on rodent control in both urban and rural areas. The problems likely to be encountered are reviewed and methods of control proposed. PMID:1085224

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

1975-01-01

5

Effect of lead nitrate on thyroid function on the Indian palm squirrel, Funambulus pennanti (Wroughton)  

SciTech Connect

Some of the known toxic effects of lead in mammals including man are, impaired heme synthesis, anemia, nepatopathy, nephropathy, behavioral disorders and neuropathy. However, very little is known about the effect of lead on endocrine physiology. Some data are available on lead induced impairment of thyroid function in occupationally exposed men and experimental rats. As lead nitrate is largely consumed through water and food, in this study the wild rodents Funambulus pennanti were administered lead through their drinking water and their thyroid structure, radioiodine 131-I percentage uptake and protein bound iodine (PBI) level were assessed.

Shrivastava, V.K.; Katti, S.R.; Sathyanesan, A.G.

1987-06-01

6

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

PubMed

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

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

2014-06-01

7

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. PMID:10860973

Sánchez-Cordero, Víctor; Martínez-Meyer, Enrique

2000-01-01

8

The island syndrome in isolated populations of a tropical forest rodent  

Microsoft Academic Search

I examined population traits of eight isolated populations of a tropical forest rodent (Proechimys semispinosus, the Central American spiny rat) for 1 year in central Panamá. Populations were sampled by monthly live-trapping, and seven traits (density, population growth rate, adult survival, reproductive effort, age structure, sex ratio, and body mass) were compared among populations. I also compared results with published

Gregory H. Adler

1996-01-01

9

Tropical rodents change rapidly germinating seeds into long-term food supplies  

Microsoft Academic Search

Seed-hoarding vertebrates may survive yearly periods of food scarcity by storing seeds during the preceding fruiting season. It is poorly understood why rodents creating long-term reserves, especially those in the tropics, incorporate seeds from plant species that germinate rapidly and hence seem unsuitable for long-term storage. We carried out a series of experiments to understand why red acouchies (Myoprocta exilis)

Patrick A. Jansen; F. J. J. M. Bongers; Herbert H. T. Prins

2006-01-01

10

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

11

Rodent seed predation: effects on seed survival, recruitment, abundance, and dispersion of bird-dispersed tropical trees.  

PubMed

Tropical tree species vary widely in their pattern of spatial dispersion. We focus on how seed predation may modify seed deposition patterns and affect the abundance and dispersion of adult trees in a tropical forest in India. Using plots across a range of seed densities, we examined whether seed predation levels by terrestrial rodents varied across six large-seeded, bird-dispersed tree species. Since inter-specific variation in density-dependent seed mortality may have downstream effects on recruitment and adult tree stages, we determined recruitment patterns close to and away from parent trees, along with adult tree abundance and dispersion patterns. Four species (Canarium resiniferum, Dysoxylum binectariferum, Horsfieldia kingii, and Prunus ceylanica) showed high predation levels (78.5-98.7%) and increased mortality with increasing seed density, while two species, Chisocheton cumingianus and Polyalthia simiarum, showed significantly lower seed predation levels and weak density-dependent mortality. The latter two species also had the highest recruitment near parent trees, with most abundant and aggregated adults. The four species that had high seed mortality had low recruitment under parent trees, were rare, and had more spaced adult tree dispersion. Biotic dispersal may be vital for species that suffer density-dependent mortality factors under parent trees. In tropical forests where large vertebrate seed dispersers but not seed predators are hunted, differences in seed vulnerability to rodent seed predation and density-dependent mortality can affect forest structure and composition. PMID:22327614

Velho, Nandini; Isvaran, Kavita; Datta, Aparajita

2012-08-01

12

Long-term melatonin administration attenuates low-LET ?-radiation-induced lymphatic tissue injury during the reproductively active and inactive phases of Indian palm squirrels (Funambulus pennanti)  

PubMed Central

A comparative analysis of low linear energy transfer (LET) ?-radiation-induced damage in the lymphatic tissue of a tropical seasonal breeder, Indian palm squirrel (Funambulus pennanti), during its reproductively active phase (RAP) and inactive phase (RIP) was performed with simultaneous investigation of the effects of long-term melatonin pre-treatment (100 ?g/100 g body weight). A total of 120 squirrels (60 during RAP and 60 during RIP) were divided into 12 groups and sacrificed at 4, 24, 48, 72 and 168 h following 5 Gy ?-radiation exposure; control groups were excluded from exposure. Total leukocyte count and absolute lymphocyte count (ALC) and melatonin only of peripheral blood, stimulation index, thiobarbituric-acid-reactive substances (TBARS) level, superoxide dismutase (SOD) activity, and the apoptotic index of spleen as analysed by terminal deoxynucleotidyl transferase (TdT)-mediated deoxyuridine triphosphate (dUTP) nick-end labelling (TUNEL) noted at observed time-points were significantly reduced in melatonin pre-treated groups during RAP and RIP. Long-term melatonin pre-treatment mitigated radiation-induced alterations more prominently during RIP, as assessed by ALC, TBARS, SOD, TUNEL and caspase-3 activity, at some time-points. Our results demonstrate an inhibitory role of melatonin on caspase-3 activity in splenocytes during RAP and RIP following ?-radiation-induced caspase-mediated apoptosis. Hence, we propose that melatonin might preserve the viability of immune cells of a seasonal breeder against background radiation, which is constantly present in the environment. PMID:20139262

Sharma, S; Haldar, C; Chaube, S K; Laxmi, T; Singh, S S

2010-01-01

13

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

14

Seed traits and taxonomic relationships determine the occurrence of mutualisms versus seed predation in a tropical forest rodent and seed dispersal system.  

PubMed

Although many studies have been carried out on plant-animal mutualistic assemblages, the roles of functional traits and taxonomy in determining both whether interactions involve mutualisms or predation and the structure of such assemblages are unclear. We used semi-natural enclosures to quantitatively assess the interaction strengths between seeds of 8 sympatric tree species and 4 rodent species in a tropical forest in Xishuangbanna, Yunnan, Southwest China. We found 2 clusters of species in the seed-rodent network represented by 2 genera in the Fagaceae (Castanopsis, Lithocarpus). Compared to seeds of 3 Castanopsis species, seeds with heavy weight, hard coat or caloric content (including 3 Lithocarpus species) were eaten less and more frequently hoarded by rodents. In turn, hoarded seeds showed less predation and more mutualism with rodents. Our results suggest that seed traits significantly affected the hoarding behavior of rodents, and, consequently, the occurrence of mutualisms and predation as well as assemblage structure in the plant-animal seed dispersal system. Taxonomically-related species with similar seed traits as functional groups belong to the same substructures in the assemblage. Our results indicate that both seed traits and taxonomic relationships may simplify thinking about seed dispersal systems by helping to elucidate whether interactions are likely to be dominated by predation or mutualism. PMID:24382317

Wang, Zhenyu; Cao, Lin; Zhang, Zhibin

2014-06-01

15

Laboratory evaluation of anticoagulant-treated baits for control of the northern palm squirrel, Funambulus pennanti Wroughton.  

PubMed Central

Individually caged northern palm squirrels, Funambulus pennanti, were fed with bait containing 0.025% warfarin or fumarin, 0.0075% chlorophacinone or 0.005% brodifacoum for a fixed number of days varying from 1 to 14. Brodifacoum (WBA 8119) was found most toxic since 66% and 70% of the animals died after one and two days' feeding respectively. Chlorophacinone killed 70% of the squirrels after three days' feeding. Squirrels were relatively tolerant to warfarin and fumarin since the mortality after a period of 14 days' feeding was only 58% and 75% respectively. PMID:7462592

Mathur, R. P.; Prakash, I.

1980-01-01

16

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

PubMed Central

Background Our interest was to find out whether pineal gland and their by melatonin act as modulator of immunosenescence. Parachlorophenylalanine (PCPA) – a ? adrenergic blocker, is known to perform chemical pinealectomy (Px) by suppressing indirectly the substrate 5-hydroxytryptamine (5-HT) for melatonin synthesis and thereby melatonin itself. The role of PCPA, alone and in combination with melatonin was recorded in immunomodulation and free radical load in spleen of young adult and aged seasonal breeder Indian palm squirrel Funambulus pennanti. Results Aged squirrel presented reduced immune parameters (i.e. total leukocyte count (TLC), Lymphocytes Count (LC), % stimulation ratio of splenocytes (% SR) against T cell mitogen concanavalin A (Con A), delayed type hypersensitivity (DTH) to oxazolone) when compared to young adult group. Melatonin administration (25 ?g/100 g body mass/day) significantly increased the immune parameters in aged more than the young adult squirrel while PCPA administration (4.5 mg/100 g body mass/day) reduced all the immune parameters more significantly in young than aged. Combination of PCPA and melatonin significantly increased the immune parameters to the normal control level of both the age groups. TBARS level was significantly high in aged than the young group. PCPA treatment increased TBARS level of young and aged squirrels both while melatonin treatment decreased it even than the controls. Nighttime peripheral melatonin level was low in control aged group than the young group. Melatonin injection at evening hours significantly increased the peripheral level of nighttime melatonin, while combined injection of PCPA and melatonin brought it to control level in both aged and young adult squirrels. Conclusion PCPA suppressed immune status more in aged than in adult by reducing melatonin level as it did chemical Px. Melatonin level decreased in control aged squirrels and so there was a decrease in immune parameters with a concomitant increase in free radical load of spleen. Decreased immune status can be restored following melatonin injection which decreased free radical load of spleen and suggest that immune organs of aged squirrels were sensitive to melatonin. Increased free radical load and decreased peripheral melatonin could be one of the reasons of immunosenescence. PMID:19389248

Rai, Seema; Haldar, Chandana; Singh, Rajesh

2009-01-01

17

Rodent Research-1 Validation of Rodent Hardware  

NASA Technical Reports Server (NTRS)

To achieve novel science objectives, validation of a rodent habitat on ISS will enable - In-flight analyses during long duration spaceflight- Use of genetically altered animals- Application of modern analytical techniques (e.g. genomics, proteomics, and metabolomics)

Globus, Ruth; Beegle, Janet

2013-01-01

18

The largest fossil rodent  

PubMed Central

The discovery of an exceptionally well-preserved skull permits the description of the new South American fossil species of the rodent, Josephoartigasia monesi sp. nov. (family: Dinomyidae; Rodentia: Hystricognathi: Caviomorpha). This species with estimated body mass of nearly 1000?kg is the largest yet recorded. The skull sheds new light on the anatomy of the extinct giant rodents of the Dinomyidae, which are known mostly from isolated teeth and incomplete mandible remains. The fossil derives from San José Formation, Uruguay, usually assigned to the Pliocene–Pleistocene (4–2?Myr ago), and the proposed palaeoenvironment where this rodent lived was characterized as an estuarine or deltaic system with forest communities. PMID:18198140

Rinderknecht, Andres; Blanco, R. Ernesto

2008-01-01

19

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. PMID:18729061

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

2008-01-01

20

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

21

Tropical Glaciers  

Microsoft Academic Search

The term ``tropical glacier'' calls to mind balmy nights and palm trees on one hand and cold, blue ice on the other. Certainly author Gabriel Garcia Marqez exploited this contrast in One Hundred Years of Solitude. We know that tropical fish live in warm, Sun-kissed waters and tropical plants provide lush, dense foliage populated by colorful tropical birds. So how

Andrew Fountain

2002-01-01

22

Sublingual vein injection in rodents  

Microsoft Academic Search

SUMMARY A simple and rapid technique for intravenous IllJection into the sub- lingual veins of common laboratory rodents is described. No prior pre- paration other than light anaesthesia is required and repeated injections can be made into the same vein. 35 The major problem associated with intravenous administration in common laboratory rodents is the inaccessibility of the veins. In most

H. B. Waynforth; R. Parkin

1969-01-01

23

Tropical Pancreatitis  

Microsoft Academic Search

Tropical pancreatitis is a special type of chronic pancreatitis that is seen mainly in tropical countries. The prevalence of tropical pancreatitis is about 126\\/100,000 population in southern India. It occurs usually in young people, involves the main pancreatic duct and results in large ductal calculi. The etiology is not known, but genetic mutations such as the SPINK1 gene mutation and

Rakesh K. Tandon; Pramod K. Garg

2004-01-01

24

Tropical Glaciers  

NASA Astrophysics Data System (ADS)

The term "tropical glacier" calls to mind balmy nights and palm trees on one hand and cold, blue ice on the other. Certainly author Gabriel Garcia Marqez exploited this contrast in One Hundred Years of Solitude. We know that tropical fish live in warm, Sun-kissed waters and tropical plants provide lush, dense foliage populated by colorful tropical birds. So how do tropical glaciers fit into this scene? Like glaciers everywhere, tropical glaciers form where mass accumulation—usually winter snow—exceeds mass loss, which is generally summer melt. Thus, tropical glaciers exist at high elevations where precipitation can occur as snowfall exceeds melt and sublimation losses, such as the Rwenzori Mountains in east Africa and the Maoke Range of Irian Jaya.

Fountain, Andrew

25

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

26

The allometry of rodent intestines  

Microsoft Academic Search

This study examined the allometry of the small intestine, caecum, colon and large intestine of rodents (n = 51) using a phylogenetically informed approach. Strong phylogenetic signal was detected in the data for the caecum, colon\\u000a and large intestine, but not for the small intestine. Most of the phylogenetic signal could be attributed to clade effects\\u000a associated with herbivorous versus omnivorous rodents.

Barry G. Lovegrove

2010-01-01

27

Probing perceptual decisions in rodents  

PubMed Central

The study of perceptual decision-making offers insight into how the brain uses complex, sometimes ambiguous information to guide actions. Understanding the underlying processes and their neural bases requires that one pair recordings and manipulations of neural activity with rigorous psychophysics. Though this research has been traditionally performed in primates, it seems increasingly promising to pursue it at least partly in mice and rats. However, rigorous psychophysical methods are not yet as developed for these rodents as they are for primates. Here we give a brief overview of the sensory capabilities of rodents and of their cortical areas devoted to sensation and decision. We then review methods of psychophysics, focusing on the technical issues that arise in their implementation in rodents. These methods represent a rich set of challenges and opportunities. PMID:23799475

Carandini, Matteo; Churchland, Anne K

2014-01-01

28

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

MedlinePLUS

... the home to help reduce the rodent population... Clean Up! Clean up rodent food sources and nesting sites... Diseases from ... up after rodents Take precautions before and during clean up of rodent-infested areas. Before cleaning, trap the ...

29

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

PubMed

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

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

2014-08-01

30

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. PMID:23610638

Wilson, Laura A B

2013-01-01

31

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

2013-04-01

32

NIH POLICY MANUAL 3043-1 -Introduction of Rodents, Rodent Products and Rodent Pathogens  

E-print Network

. · NIH Manual System, contact the Office of Management Assessment, OM, on (301) 496- 4606 · Online poses a risk to both established rodent colonies and to the humans who come into contact with infected colonies and research mission. It is the goal of this policy to establish a dynamic balance between

Bandettini, Peter A.

33

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. PMID:4587482

Wodzicki, Kazimierz

1973-01-01

34

Tropical Deforestation.  

ERIC Educational Resources Information Center

Outlines the deforestation problem and some efforts for solving the problem. Considers the impact of population growth, poverty, and ignorance. Includes a discussion of the current rapid decline in tropical forests, the consequences of destruction, and an outlook for the future. (YP)

Raven, Peter H.

1988-01-01

35

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. PMID:8933060

Ashby, J

1996-01-01

36

Tropical Islands Jan Verschelde  

E-print Network

Tropical Islands Jan Verschelde University of Illinois at Chicago Department of Mathematics Algebraic Geometry Seminar Jan Verschelde (UIC) Tropical Islands 16 January 2014 1 / 26 #12;Tropical Islands Verschelde (UIC) Tropical Islands 16 January 2014 2 / 26 #12;Tropical Islands 1 Introduction Introduction

Verschelde, Jan

37

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

38

Rodent-Vegetation Relationships in Southeastern Montana  

Microsoft Academic Search

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

Daniel W. Uresk; Richard M. Hansen

39

Tropical Convection's Roles in Tropical Tropopause Cirrus  

NASA Technical Reports Server (NTRS)

The results presented here show that tropical convection plays a role in each of the three primary processes involved in the in situ formation of tropopause cirrus. First, tropical convection transports moisture from the surface into the upper troposphere. Second, tropical convection excites Rossby waves that transport zonal momentum toward the ITCZ, thereby generating rising motion near the equator. This rising motion helps transport moisture from where it is detrained from convection to the cold-point tropopause. Finally, tropical convection excites vertically propagating tropical waves (e.g. Kelvin waves) that provide one source of large-scale cooling near the cold-point tropopause, leading to tropopause cirrus formation.

Boehm, Matthew T.; Starr, David OC.; Verlinde, Johannes; Lee, Sukyoung

2002-01-01

40

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

PubMed Central

Background Comparative analysis, which aims at investigating ecological and evolutionary patterns among species, may help at targeting reservoirs of zoonotic diseases particularly in countries presenting high biodiversity. Here, we developed a simple method to target rodent reservoirs using published studies screening microparasite infections. Methods We compiled surveys of microparasites investigated in rodents trapped in Thailand. The data comprise a total of 17,358 rodents from 18 species that have been investigated for a total of 10 microparasites (viruses, bacteria and protozoans). We used residual variation of microparasite richness controlled for both rodent sample size and pathogens’ screening effort to identify major rodent reservoirs and potential risky habitats. Results Microparasite species richness was positively related to rodent sample size and pathogens’ screening effort. The investigation of the residual variations of microparasite species richness showed that several rodent species harboured more pathogens than expected by the regression model. Similarly, higher pathogen richness than expected was observed in rodents living in non-flooded lands, forests and paddy fields. Conclusion Our results suggest to target some rodent species that are not commonly investigated for pathogen screening or surveillance such as R. adamanensis or B. savilei, and that non-flooded lands and forests should be more taken into caution, whereas much surveys focused on paddy rice fields and households. PMID:22957129

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

2012-01-01

41

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

42

21 CFR 1250.96 - Rodent control.  

Code of Federal Regulations, 2011 CFR

...REGULATIONS UNDER CERTAIN OTHER ACTS ADMINISTERED BY THE FOOD AND DRUG ADMINISTRATION INTERSTATE CONVEYANCE SANITATION Sanitation Facilities and Conditions on Vessels § 1250.96 Rodent control. Vessels shall be maintained free of...

2011-04-01

43

21 CFR 1250.96 - Rodent control.  

...REGULATIONS UNDER CERTAIN OTHER ACTS ADMINISTERED BY THE FOOD AND DRUG ADMINISTRATION INTERSTATE CONVEYANCE SANITATION Sanitation Facilities and Conditions on Vessels § 1250.96 Rodent control. Vessels shall be maintained free of...

2014-04-01

44

21 CFR 1250.96 - Rodent control.  

Code of Federal Regulations, 2013 CFR

...REGULATIONS UNDER CERTAIN OTHER ACTS ADMINISTERED BY THE FOOD AND DRUG ADMINISTRATION INTERSTATE CONVEYANCE SANITATION Sanitation Facilities and Conditions on Vessels § 1250.96 Rodent control. Vessels shall be maintained free of...

2013-04-01

45

21 CFR 1250.96 - Rodent control.  

Code of Federal Regulations, 2012 CFR

...REGULATIONS UNDER CERTAIN OTHER ACTS ADMINISTERED BY THE FOOD AND DRUG ADMINISTRATION INTERSTATE CONVEYANCE SANITATION Sanitation Facilities and Conditions on Vessels § 1250.96 Rodent control. Vessels shall be maintained free of...

2012-04-01

46

21 CFR 1250.96 - Rodent control.  

Code of Federal Regulations, 2010 CFR

...REGULATIONS UNDER CERTAIN OTHER ACTS ADMINISTERED BY THE FOOD AND DRUG ADMINISTRATION INTERSTATE CONVEYANCE SANITATION Sanitation Facilities and Conditions on Vessels § 1250.96 Rodent control. Vessels shall be maintained free of...

2010-04-01

47

Mammals. Key to Rodents (Mlekopitayushchie. Opredelitel Gryzunov).  

National Technical Information Service (NTIS)

This is a comprehensive work on rodents (suborder Glires) of the USSR and adjacent eastern European and northern Asian territories. Among the subjects treated are: evolution, morphology, taxonomy, mode of life, and geographical distribution. This last is ...

S. B. Vinogradov, A. I. Argiropulo

1968-01-01

48

Tropical forests  

SciTech Connect

Major international aid and nongovernmental groups have agreed on a strategy to conserve tropical forests. Their plan calls for a $5.3 billion, five-year program for the 56 most critically affected countries. This report consists of three parts. The Plan details the costs of deforestation in both developing and industrialized countries, uncovers its real causes, and outlines a five-part action plan. Case Studies reviews dozens of detailed accounts of successful forest management projects from around the world, covering wide-ranging ecological conditions and taking into account the economics of forest products in different marketing situations. Country Investment Profiles spell out country-by-country listings of what should be done, who should do it, and how much it will cost.

Not Available

1985-01-01

49

Rodents as potential couriers for bioterrorism agents.  

PubMed

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

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

2013-09-01

50

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

2013-10-01

51

The Fecal Viral Flora of Wild Rodents  

PubMed Central

The frequent interactions of rodents with humans make them a common source of zoonotic infections. To obtain an initial unbiased measure of the viral diversity in the enteric tract of wild rodents we sequenced partially purified, randomly amplified viral RNA and DNA in the feces of 105 wild rodents (mouse, vole, and rat) collected in California and Virginia. We identified in decreasing frequency sequences related to the mammalian viruses families Circoviridae, Picobirnaviridae, Picornaviridae, Astroviridae, Parvoviridae, Papillomaviridae, Adenoviridae, and Coronaviridae. Seventeen small circular DNA genomes containing one or two replicase genes distantly related to the Circoviridae representing several potentially new viral families were characterized. In the Picornaviridae family two new candidate genera as well as a close genetic relative of the human pathogen Aichi virus were characterized. Fragments of the first mouse sapelovirus and picobirnaviruses were identified and the first murine astrovirus genome was characterized. A mouse papillomavirus genome and fragments of a novel adenovirus and adenovirus-associated virus were also sequenced. The next largest fraction of the rodent fecal virome was related to insect viruses of the Densoviridae, Iridoviridae, Polydnaviridae, Dicistroviriade, Bromoviridae, and Virgaviridae families followed by plant virus-related sequences in the Nanoviridae, Geminiviridae, Phycodnaviridae, Secoviridae, Partitiviridae, Tymoviridae, Alphaflexiviridae, and Tombusviridae families reflecting the largely insect and plant rodent diet. Phylogenetic analyses of full and partial viral genomes therefore revealed many previously unreported viral species, genera, and families. The close genetic similarities noted between some rodent and human viruses might reflect past zoonoses. This study increases our understanding of the viral diversity in wild rodents and highlights the large number of still uncharacterized viruses in mammals. PMID:21909269

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

2011-01-01

52

Sporadic amplification of ID elements in rodents.  

PubMed

ID sequences are members of a short interspersed element (SINE) repetitive DNA family within the rodent genome. The copy number of individual ID elements varies by up to three orders of magnitude between species. This amplification has been highly sporadic in the order Rodentia and does not follow any phylogenetic trend. Using library screening and dot-blot analysis, we estimate there are 25,000 copies of ID elements in the deer mouse, 1,500 copies in the gerbil (both cricetid rodents), and 60,000 copies of either ID or ID-like elements in a sciurid rodent (squirrel). By dot-blot analysis, we estimate there are 150,000, 4,000, 1,000, and 200 copies of ID elements in the rat, mouse, hamster, and guinea pig, respectively (which is consistent with previous reports) and 200 copies in the hystricognath rodent, nutria. Therefore, a rapid amplification took place not only after the divergence of rat and mouse but also following the deer mouse (Peromyscus) and hamster split, with no evidence of increased amplifications in hystricognath rodents. No notable variations of sequences from the BC1 genes of several myomorphic rodents were observed that would possibly explain the varied levels of ID amplification. We did observe subgenera and species-group-specific variation in the ID core sequence of the BC1 gene within the genus Peromyscus. Sequence analysis of cloned ID elements in Peromyscus show most ID elements in this genus arose prior to Peromyscus subgenus divergence. Correspondence of the consensus sequence of individual ID elements in gerbil and deer mouse further confirms BC1 as a master gene in ID amplification. Several possible mechanisms responsible for the quantitative variations are explored. PMID:8576967

Kass, D H; Kim, J; Deininger, P L

1996-01-01

53

Tropical observability and predictability  

E-print Network

Many studies have investigated tropical data assimilation in the context of global models or specifically for tropical cyclones, but relatively few have focused on the mesoscale predictability and observability of the ...

Whitcomb, Timothy Robert

2008-01-01

54

Genospecies diversity of Lyme disease spirochetes in rodent reservoirs.  

PubMed Central

To determine whether particular Borrelia burgdorferi s.l. genospecies associate solely with rodent reservoir hosts, we compared the genospecies prevalence in questing nymphal Ixodes ticks with that in xenodiagnostic ticks that had fed as larvae on rodents captured in the same site. No genospecies was more prevalent in rodent-fed ticks than in questing ticks. The three main spirochete genospecies, therefore, share common rodent hosts. PMID:10221886

Richter, D.; Endepols, S.; Ohlenbusch, A.; Eiffert, H.; Spielman, A.; Matuschka, F. R.

1999-01-01

55

Environmental factors associated with rodent infestations in Argentine poultry farms.  

PubMed

1. Seasonal variations in rodent infestations were studied at poultry farms in central Argentina as well as the environmental factors associated with rodent infestations at poultry farms. 2. During the summer and winter of 1998 rodent infestation was monitored at 10 poultry farms by means of tracking stations, and 21 environmental variables were selected that a priori could be related with the extent of rodent infestation. 3. There was a higher rodent infestation in winter than in summer. 4. Species detected by rodent sightings at the poultry farms included Akodon azarae, Calomys spp. (C. laucha and possibly C. musculinus) and Mus musculus. 5. In summer, rodent infestation was positively associated with the perimeter of the farm, whereas there was an inverse relationship with the maintenance conditions of the sheds. In winter, rodent infestation was positively associated with the percentage of the borders of the farm covered with vegetation, and with the amount of plant cover, especially the amount of plant cover which was above 20 cm in height. 6. There was no significant relationship between rodent infestation and the time lag since the last application of rodenticide (first-generation anticoagulant) at the farms. 7. These results suggest that strategies for controlling rodents based solely on chemical methods may not be good enough for efficient rodent control. Farms which are properly managed, with a better control of vegetation growth at both the perimeter and within the internal area, in addition to a higher maintenance of sheds have appreciably lower rodent infestations. PMID:11469547

Villafane IEG; Bilenca, D N; Cavia, R; Miño, M H; Cittadino, E A; Busch, M

2001-07-01

56

Northwestern University New Researcher Checklist: Evanston Campus Rodent Users  

E-print Network

and Access to CCM Facilities Register for Facility Orientation and Hands-On Rodent Euthanasia o Contact the CCM Training Office to register for Facility Orientation and Hands-On Rodent Euthanasia training: 312-503-2758 o Facility Orientation and Hands-On Rodent Euthanasia are: Held on Tuesdays at 10:30am and Fridays

Contractor, Anis

57

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

58

Rodents as reservoirs of parasites in India.  

PubMed

We monitored the prevalence of endoparasitic infections of rodents in Punjab State, India, between January 2004 and December 2005. Three species of wild rodents, namely the house rat, Rattus rattus (n= 42), the lesser bandicoot rat, Bandicota bengalensis (n= 34) and the Indian gerbil, Tatera indica (n= 15), were live-captured from houses and crop fields. Examination of various organs revealed that the highest rates of endoparasitic infection occurred in R. rattus (40.5%), followed by B. bengalensis (35.3 %) and then T. indica (20.0%), with an overall infection rate of 35.2%. All three rodent species were found naturally infected with one or more species of helminths. Metacestodes (1-6) of Cysticercus fasciolaris (larvae of Taenia taeniaeformis) were found in all three rodent species (in the liver). In one male T. indica, numerous robust T. taeniaeformis metacestodes were found in oval sacs attached to the mesentery and the abdominal wall, an unusual site. The cauda epididymal fluid of the same gerbil was also found to be infected with a very rare species of strongylid nematode, which could not be identified to genus or species level. It is possible that this nematode is transmitted sexually and thus may affect the reproductive potential of gerbils. This appears to be the first report of this phenomenon. In one B. bengalensis individual, the intestine was found to be obstructed with an acanthocephalan, Moniliformis moniliformis, with concurrent infection with C. fasciolaris in the form of multiple cysts in the liver. Although no natural protozoan infection was found in these field rodents, experimental Trypanosoma evansi infection has been established in all three species with high pathogenicity, and the possibility of sexual transmission was supported by the presence of T. evansi in the cauda epididymal fluid of male rats. PMID:21396047

Singla, Lachhman D; Singla, Neena; Parshad, Vir R; Juyal, Prayag D; Sood, Naresh K

2008-03-01

59

Novel Rodent Models for Macular Research  

PubMed Central

Background Many disabling human retinal disorders involve the central retina, particularly the macula. However, the commonly used rodent models in research, mouse and rat, do not possess a macula. The purpose of this study was to identify small laboratory rodents with a significant central region as potential new models for macular research. Methodology/Principal Findings Gerbillus perpallidus, Meriones unguiculatus and Phodopus campbelli, laboratory rodents less commonly used in retinal research, were subjected to confocal scanning laser ophthalmoscopy (cSLO), fluorescein and indocyanine green angiography, and spectral-domain optical coherence tomography (SD-OCT) using standard equipment (Heidelberg Engineering HRA1 and Spectralis™) adapted to small rodent eyes. The existence of a visual streak-like pattern was assessed on the basis of vascular topography, retinal thickness, and the topography of retinal ganglion cells and cone photoreceptors. All three species examined showed evidence of a significant horizontal streak-like specialization. cSLO angiography and retinal wholemounts revealed that superficial retinal blood vessels typically ramify and narrow into a sparse capillary net at the border of the respective area located dorsal to the optic nerve. Similar to the macular region, there was an absence of larger blood vessels in the streak region. Furthermore, the thickness of the photoreceptor layer and the population density of neurons in the ganglion cell layer were markedly increased in the visual streak region. Conclusions/Significance The retinal specializations of Gerbillus perpallidus, Meriones unguiculatus and Phodopus campbelli resemble features of the primate macula. Hence, the rodents reported here may serve to study aspects of macular development and diseases like age-related macular degeneration and diabetic macular edema, and the preclinical assessment of therapeutic strategies. PMID:20976212

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

2010-01-01

60

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

2012-08-20

61

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

E-print Network

Sustained high levels of neuregulin-1 in the longest-lived rodents; a key determinant of rodent 31905, Israel Summary Naked mole-rats (Heterocephalus glaber), the longest-lived rodents, live 7% of their lives. Little is known about the mechanisms that allow them to delay the aging process and live so long

Huchon, Dorothée

62

Tropical Convection's Roles in Tropical Tropopause Cirrus  

NASA Technical Reports Server (NTRS)

Remote sensing observations reveal the frequent occurrence of tropopause cirrus, thin cirrus layers located near the tropical cold-point tropopause. Here, we present a theory in which tropical convection plays several important roles in tropopause cirrus formation. First, tropical convection is the primary means by which the moisture required for tropopause cirrus formation is transported into the upper troposphere. However, previous studies suggest that this convection rarely penetrates to the altitudes at which tropopause cirrus layers are observed, suggesting that additional vertical moisture transport is required to explain tropopause cirrus formation. We propose a mechanism for explaining this transport in which tropical convection plays the key role. According to this hypothesis, the transport is accomplished by meridional circulations that develop within the tropopause transition layer (TTL) in response to momentum transport by Rossby waves generated by tropical convection. Results of a series of global scale model runs designed to test this hypothesis will be presented. In addition, reanalyses vertical velocity data will be examined for evidence of the expected correlation between large-scale rising motion within the TTL and tropical convection. Once moisture is present near the cold-point tropopause, large-scale cooling is required to initiate tropopause cirrus formation. One source of this cooling is stratospheric tropical waves induced by tropical convection, as we will show using a time series of radiosonde temperature data superimposed with data on cloud occurrence from the DOE ARM Nauru99 field experiment. Observations of the global characteristics of these waves from a longer time series of reanalysis data will also be presented.

Boehm, Matthew T.; Starr, David OC.; Verlinde, Johannes; Lee, Sukyoung

2002-01-01

63

Tropical splenomegaly. Part 1: Tropical Africa.  

PubMed

The emergence of tropical splenomegaly syndrome as a distinct entity in tropical medical practice has been briefly described, together with its link with malaria. The clinical and haematological aspects of the syndrome have been reviewed with some emphasis on local experience. No attempt has been made to give details of the immunological aspects, but the mechanisms by which the established immunological features of the disease help to understand the pathogenesis of the syndrome have been highlighted. PMID:7030559

Fakunle, Y M

1981-10-01

64

Cage allocation designs for rodent carcinogenicity experiments.  

PubMed Central

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

Herzberg, A M; Lagakos, S W

1992-01-01

65

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. PMID:22608070

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

2013-01-01

66

Evidence for Novel Hepaciviruses in Rodents  

PubMed Central

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

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

2013-01-01

67

Growth of Francisella spp. in rodent macrophages.  

PubMed Central

We examined the nature of the interactions between the facultative intracellular pathogens Francisella tularensis and F. novicida and rodent macrophages. Growth of F. tularensis LVS was observed in macrophage monolayers from mice, guinea pigs, or rats. In contrast, F. novicida grew in macrophages from mice and guinea pigs but not in macrophages from rats. Transmission electron microscopy studies indicated that both Francisella species survive within macrophage phagosomes that are unfused with lysosomes. Images PMID:1879943

Anthony, L D; Burke, R D; Nano, F E

1991-01-01

68

Partial Rodent Genetic Models for Bipolar Disorder  

Microsoft Academic Search

\\u000a Bipolar disorder (BPD) is a complex clinical phenomenon. This episodic illness comprises at least four features\\/components:\\u000a depression, mania, vulnerability to mood swings in euthymic BPD patients, and spontaneous cyclicity in at least some BPD patients.\\u000a Currently, there is no rodent genetic model capable of encompassing the whole phenotype of BPD exists; however, recent genetic-behavioral\\u000a studies have delineated partial models for

Guang Chen; Ioline D. Henter; Husseini K. Manji

69

Neurogenetics of aggressive behavior: studies in rodents.  

PubMed

Aggressive behavior is observed in many animal species, such as insects, fish, lizards, frogs, and most mammals including humans. This wide range of conservation underscores the importance of aggressive behavior in the animals' survival and fitness, and the likely heritability of this behavior. Although typical patterns of aggressive behavior differ between species, there are several concordances in the neurobiology of aggression among rodents, primates, and humans. Studies with rodent models may eventually help us to understand the neurogenetic architecture of aggression in humans. However, it is important to recognize the difference between the ecological and ethological significance of aggressive behavior (species-typical aggression) and maladaptive violence (escalated aggression) when applying the findings of aggression research using animal models to human or veterinary medicine. Well-studied rodent models for aggressive behavior in the laboratory setting include the mouse (Mus musculus), rat (Rattus norvegicus), hamster (Mesocricetus auratus), and prairie vole (Microtus ochrogaster). The neural circuits of rodent aggression have been gradually elucidated by several techniques, e.g., immunohistochemistry of immediate-early gene (c-Fos) expression, intracranial drug microinjection, in vivo microdialysis, and optogenetics techniques. Also, evidence accumulated from the analysis of gene-knockout mice shows the involvement of several genes in aggression. Here, we review the brain circuits that have been implicated in aggression, such as the hypothalamus, prefrontal cortex (PFC), dorsal raphe nucleus (DRN), nucleus accumbens (NAc), and olfactory system. We then discuss the roles of glutamate and ?-aminobutyric acid (GABA), excitatory and inhibitory amino acids in the brain, as well as their receptors, in controlling aggressive behavior, focusing mainly on recent findings. At the end of this chapter, we discuss how genes can be identified that underlie individual differences in aggression, using the so-called forward genetics approach. PMID:24318936

Takahashi, Aki; Miczek, Klaus A

2014-01-01

70

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. PMID:23671868

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

2013-01-01

71

Tropical Prediction Center  

NSDL National Science Digital Library

The Tropical Prediction Center Web site is maintained by the National Weather Service of NOAA. Visitors will find current information on tropical storms and hurricanes, including public advisories. Also available are hurricane facts, historical data, tracking charts, satellite imagery, season summaries, and a wealth of other interesting and important information.

72

Topics in Tropical Meteorology  

NSDL National Science Digital Library

This module brings together six short lessons about significant atmospheric and oceanic influences on tropical cyclone development in the Atlantic Ocean. Topics treated include the African Easterly Jet, the Loop Current, the Meridional Overturning Circulation, ocean heat content, the Saharan Air Layer, and the Tropical Upper Tropospheric Trough, or TUTT.

Comet

2008-12-22

73

Conceptual Models of Tropical Waves  

NSDL National Science Digital Library

Tropical waves are prolific rainfall producers that sometimes form tropical cyclones. Conceptual models of tropical waves are used to help learners understand the dynamical characteristics and evolution of tropical waves. Users will learn about the vertical and horizontal structure of tropical waves and the typical weather changes that accompany the passage of a tropical wave. Four different methods of tracking tropical waves are also provided. The Webcast is presented by Mr. Horace Burton and Mr. Selvin Burton of the Caribbean Institute for Meteorology and Hydrology under the auspices of the MeteoForum Project.

Comet

2006-04-21

74

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

75

An Overview of Tropical Meteorology  

NSDL National Science Digital Library

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

2009-01-01

76

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

77

ORIGINAL PAPER Island prioritization for invasive rodent eradications  

E-print Network

/ Accepted: 1 December 2011 Ã? Springer Science+Business Media B.V. 2011 Abstract Invasive rodents occur that long-term conserva- tion gain should be the primary focus when prioritising islands for invasive rodent weights to levels of unit reinvasion risk and unit conservation value. The choice of parameter weights may

Courchamp, Franck

78

Competition between harvester ants and rodents in the cold desert  

Microsoft Academic Search

Local distribution patterns of three rodent species (Perognathus parvus, Peromyscus maniculatus, Reithrodontomys megalotis) were studied in areas of high and low densities of harvester ants (Pogonomyrmex owyheei) in Raft River Valley, Idaho. Numbers of rodents were greatest in areas of high ant-density during May, but partially reduced in August; whereas, the trend was reversed in areas of low ant-density. Seed

D. S. Landeen; C. D. Jorgensen; H. D. Smith

1979-01-01

79

Ultrasonic attenuation imaging in a rodent thyroid cancer model  

E-print Network

Ultrasonic attenuation imaging in a rodent thyroid cancer model Omar Zenteno¹, William Ridgway-Champaign, Urbana, IL 61801, USA. Abstract--The incidence of diagnosed thyroid cancer has increased significantly may allow differentiating among different types of thyroid tumors and normal tissues in a rodent model

Illinois at Urbana-Champaign, University of

80

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...

81

Genome sequence and comparative analysis of the model rodent malaria  

E-print Network

Genome sequence and comparative analysis of the model rodent malaria parasite Plasmodium yoelii Medical Centre, PO Box 9600, 2300 RC Leiden, The Netherlands § Naval Medical Research Center, Malaria ........................................................................................................................................................................................................................... Species of malaria parasite that infect rodents have long been used as models for malaria disease research

Salzberg, Steven

82

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

83

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. PMID:182403

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

1975-01-01

84

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

85

Deforestation in the Tropics  

Microsoft Academic Search

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

Robert Repetto

1990-01-01

86

Tropical Severe Local Storms  

NSDL National Science Digital Library

The module provides a brief overview of severe local storms in the tropics. Basic ingredients for thunderstorms and assessment of thunderstorm potential from soundings are described. Then properties and hazards of ordinary thunderstorms, multicellular thunderstorms, supercells are reviewed. Conditions conducive to supercell formation in the tropics are examined along with methods of identifying them in radar and satellite images. Supercell and non-supercell tornado properties and formation are described. Finally, tornadoes, waterspouts, and dust devils properties are compared.

Comet

2013-01-09

87

Rodent borne diseases and their fleas in Menoufia Governorate, Egypt.  

PubMed

A preliminary survey of domestic rodent borne diseases and their fleas was carried out in ten centers of Menofiya (Quesna, Shebeen El-Kom, Berka El-Saabe, El-Bagour, El-Shohada, Tala, Menoff, Searth El-Lian, Ashmon and El-Sadat) Governorate, Egypt. Rodent index (number of rodent / trap) and percentage frequency of different rodent species were recorded in spring (2009). The main species was Norway rat, Rattus norvegicus, the grey-bellied rat, R. rattus alexandrinus, the white- bellied rat, R. rattus frugivorus and the house mouse, Mus musculus. Searth El-Lian center showed the highest existing rodent- index, while Quesna center showed the lowest existing rodent-index. The Norway rat, R. norvegicus showed higher frequency at Shebeen El-Kom, Berka El-Saabe, El-Baguur, Searth El-Lian and El-Sadat. R. rattus alexandrinus showed higher frequency at Tala center, while Rattus rattusfrugivorus showed higher frequency at El-Shohada, Menoff and Ashmon. M. masculus showed the lower frequency at all centers. The common flea species attacking rodents at all centers were: the oriental rat flea, Xenopsylla cheopis, the mouse flea, Lyptopsylla segnis and the dog flea, Ctenocephalides canis. The flea index (number of flea/rodent) at Searth El-Lian was the highest, while Shebeen El- Kom showed the lowest index. The oriental rat flea, X. cheopis was the highest frequency distribution for all domestic rodent species studied while, the dog flea, C.s canis was the lowest. The adult rodents showed the higher frequency with fleas than juveniles. PMID:20503591

Soliman, Mohamed Ismail; Abd El-Halim, Azza S; Mikhail, Micheal W

2010-04-01

88

Guidelines for Euthanasia of Rodents Using Carbon Dioxide Rodents must be euthanized by trained personnel using appropriate technique, equipment and  

E-print Network

1 Guidelines for Euthanasia of Rodents Using Carbon Dioxide Rodents must be euthanized by trained, euthanasia should not be performed in the animal room. The euthanasia method must be appropriate to the most recent AVMA Guidelines on Euthanasia.1 CO2 inhalation is the most common method of euthanasia used

Bandettini, Peter A.

89

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. PMID:20668546

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

2010-01-01

90

Endotoxin-induced uveitis in rodents.  

PubMed

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

Yadav, Umesh C S; Ramana, Kota V

2013-01-01

91

Intraoperative cerebral blood flow imaging of rodents  

NASA Astrophysics Data System (ADS)

Intraoperative monitoring of cerebral blood flow (CBF) is of interest to neuroscience researchers, which offers the assessment of hemodynamic responses throughout the process of neurosurgery and provides an early biomarker for surgical guidance. However, intraoperative CBF imaging has been challenging due to animal's motion and position change during the surgery. In this paper, we presented a design of an operation bench integrated with laser speckle contrast imager which enables monitoring of the CBF intraoperatively. With a specially designed stereotaxic frame and imager, we were able to monitor the CBF changes in both hemispheres during the rodent surgery. The rotatable design of the operation plate and implementation of online image registration allow the technician to move the animal without disturbing the CBF imaging during surgery. The performance of the system was tested by middle cerebral artery occlusion model of rats.

Li, Hangdao; Li, Yao; Yuan, Lu; Wu, Caihong; Lu, Hongyang; Tong, Shanbao

2014-09-01

92

Intraoperative cerebral blood flow imaging of rodents.  

PubMed

Intraoperative monitoring of cerebral blood flow (CBF) is of interest to neuroscience researchers, which offers the assessment of hemodynamic responses throughout the process of neurosurgery and provides an early biomarker for surgical guidance. However, intraoperative CBF imaging has been challenging due to animal's motion and position change during the surgery. In this paper, we presented a design of an operation bench integrated with laser speckle contrast imager which enables monitoring of the CBF intraoperatively. With a specially designed stereotaxic frame and imager, we were able to monitor the CBF changes in both hemispheres during the rodent surgery. The rotatable design of the operation plate and implementation of online image registration allow the technician to move the animal without disturbing the CBF imaging during surgery. The performance of the system was tested by middle cerebral artery occlusion model of rats. PMID:25273744

Li, Hangdao; Li, Yao; Yuan, Lu; Wu, Caihong; Lu, Hongyang; Tong, Shanbao

2014-09-01

93

Functional assessments in the rodent stroke model  

PubMed Central

Stroke is a common cause of permanent disability accompanied by devastating impairments for which there is a pressing need for effective treatment. Motor, sensory and cognitive deficits are common following stroke, yet treatment is limited. Along with histological measures, functional outcome in animal models has provided valuable insight to the biological basis and potential rehabilitation efforts of experimental stroke. Developing and using tests that have the ability to identify behavioral deficits is essential to expanding the development of translational therapies. The present aim of this paper is to review many of the current behavioral tests that assess functional outcome after stoke in rodent models. While there is no perfect test, there are many assessments that are sensitive to detecting the array of impairments, from global to modality specific, after stroke. PMID:20642841

2010-01-01

94

Epigallocatechin gallate supplementation alleviates diabetes in rodents.  

PubMed

As the prevalence of type 2 diabetes mellitus is increasing at an alarming rate, effective nutritional and exercise strategies for the prevention of this disease are required. Specific dietary components with antidiabetic efficacy could be one aspect of these strategies. This study investigated the antidiabetic effects of the most abundant green tea catechin, epigallocatechin gallate (EGCG, TEAVIGO), in rodent models of type 2 diabetes mellitus and H4IIE rat hepatoma cells. We assessed glucose and insulin tolerance in db/db mice and ZDF rats after they ingested EGCG. Using gene microarray and real-time quantitative RT-PCR we investigated the effect of EGCG on gene expression in H4IIE rat hepatoma cells as well as in liver and adipose tissue of db/db mice. EGCG improved oral glucose tolerance and blood glucose in food-deprived rats in a dose-dependent manner. Plasma concentrations of triacylglycerol were reduced and glucose-stimulated insulin secretion was enhanced. In H4IIE cells, EGCG downregulated genes involved in gluconeogenesis and the synthesis of fatty acids, triacylgycerol, and cholesterol. EGCG decreased the mRNA expression of phosphoenolpyruvate carboxykinase in H4IIE cells as well as in liver and adipose tissue of db/db mice. Glucokinase mRNA expression was upregulated in the liver of db/db mice in a dose-dependent manner. This study shows that EGCG beneficially modifies glucose and lipid metabolism in H4IIE cells and markedly enhances glucose tolerance in diabetic rodents. Dietary supplementation with EGCG could potentially contribute to nutritional strategies for the prevention and treatment of type 2 diabetes mellitus. PMID:16988119

Wolfram, Swen; Raederstorff, Daniel; Preller, Mareike; Wang, Ying; Teixeira, Sandra R; Riegger, Christoph; Weber, Peter

2006-10-01

95

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

96

Interactions among unrelated species: Granivorous rodents, a parasitic fungus, and a shared prey species  

Microsoft Academic Search

Granivorous rodents and a parasitic fungus in the Sonoran Desert utilize a common prey species, Erodium cicutarium, a desert annual plant. Experimental removal of rodents from field exclosures resulted in significantly higher densities of E. cicutarium. Fungal infection was significantly higher in the absence of rodents, suggesting that, while they do not interact directly, rodents and the fungus affect each

Richard S. Inouye

1981-01-01

97

Tropical Mesoscale Convective Systems  

NSDL National Science Digital Library

Mesoscale Convective Systems (MCSs) occur globally and can account for significant percentages of the annual precipitation in some locations. MCSs are responsible for flooding as well as damaging surface winds in some instances. Thus, it is important for forecasters to understand when, where, and how MCSs develop and maintain themselves. This module covers all modes of MCSs with a strong focus on the tropics and the different aspects that brings to MCS development, maintenance, and structure. It describes conceptual models of MCSs and the dynamical and physical processes that influence their evolution. Also included are examples of MCSs from various areas of the tropics.

Comet

2013-05-14

98

Tropical Rainfall Measuring Mission  

NASA Technical Reports Server (NTRS)

Tropical rainfall affects the lives and economics of a majority of the Earth's population. Tropical rain systems, such as hurricanes, typhoons, and monsoons, are crucial to sustaining the livelihoods of those living in the tropics. Excess rainfall can cause floods and great property and crop damage, whereas too little rainfall can cause drought and crop failure. The latent heat release during the process of precipitation is a major source of energy that drives the atmospheric circulation. This latent heat can intensify weather systems, affecting weather thousands of kilometers away, thus making tropical rainfall an important indicator of atmospheric circulation and short-term climate change. Tropical forests and the underlying soils are major sources of many of the atmosphere's trace constituents. Together, the forests and the atmosphere act as a water-energy regulating system. Most of the rainfall is returned to the atmosphere through evaporation and transpiration, and the atmospheric trace constituents take part in the recycling process. Hence, the hydrological cycle provides a direct link between tropical rainfall and the global cycles of carbon, nitrogen, and sulfur, all important trace materials for the Earth's system. Because rainfall is such an important component in the interactions between the ocean, atmosphere, land, and the biosphere, accurate measurements of rainfall are crucial to understanding the workings of the Earth-atmosphere system. The large spatial and temporal variability of rainfall systems, however, poses a major challenge to estimating global rainfall. So far, there has been a lack of rain gauge networks, especially over the oceans, which points to satellite measurement as the only means by which global observation of rainfall can be made. The Tropical Rainfall Measuring Mission (TRMM), jointly sponsored by the National Aeronautics and Space Administration (NASA) of the United States and the National Space Development Agency (NASDA) of Japan, provides visible, infrared, and microwave observations of tropical and subtropical rain systems.The satellite observations are complemented by ground radar and rain gauge measurements to validate satellite rain estimation techniques. Goddard Space Flight Center's involvement includes the observatory, four instruments, integration and testing of the observatory, data processing and distribution, and satellite operations. TRMM has a design lifetime of three years. Data generated from TRMM and archived at the GDAAC are useful not only for hydrologists, atmospheric scientists, and climatologists, but also for the health community studying infectious diseases, the ocean research community, and the agricultural community.

1999-01-01

99

Linear systems on tropical curves  

Microsoft Academic Search

A tropical curve ? is a metric graph with possibly unbounded edges, and tropical rational functions are continuous piecewise\\u000a linear functions with integer slopes. We define the complete linear system |D| of a divisor D on a tropical curve ? analogously to the classical counterpart. We investigate the structure of |D| as a cell complex and show that linear systems

Christian Haase; Gregg Musiker; Josephine Yu

100

Allocentric directional processing in the rodent and human retrosplenial cortex  

PubMed Central

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

Knight, Rebecca; Hayman, Robin

2014-01-01

101

40 CFR 798.5450 - Rodent dominant lethal assay.  

Code of Federal Regulations, 2011 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...

2011-07-01

102

40 CFR 798.5450 - Rodent dominant lethal assay.  

Code of Federal Regulations, 2010 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...

2010-07-01

103

Swimming ability in three Costa Rican dry forest rodents  

E-print Network

We investigated the swimming abilities of three Costa Rican dry forest rodents (Coues' rice rat. Oryzomys couesi, hispid cotton rat, Sigmodon hispidus, and spiny pocket mouse, Liomys salvini) associated with a large marsh, ...

Cook, William M.; Timm, Robert M.; Hymen, Dena E.

2001-12-01

104

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. PMID:10970147

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

2000-01-01

105

Ejaculate investment in a promiscuous rodent, Peromyscus maniculatus: effects of  

E-print Network

Ejaculate investment in a promiscuous rodent, Peromyscus maniculatus: effects of population density, somatic mass and annual population density for wild-caught male deer mice, Peromyscus maniculatus rank. Keywords: ejaculate investment, mating system, Peromyscus maniculatus, population density, sexual

Montgomerie, Bob

106

Induced transgenerational genetic effects in rodents and humans.  

PubMed

Delayed appearance of induced mutations has been observed in Drosophila, plants, rodents and recently in humans. The significance of this phenomenon is now recognized especially after the pioneering work of Nomura demonstrating transgenerational tumour induction in mice following treatment with urethane or ionizing radiation. A brief review of the literature on transgenerational genetic effects, namely, chromosomal aberrations and mutations, in rodents and humans is presented here. PMID:17019051

Natarajan, A T

2006-01-01

107

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

2010-02-01

108

Hindlimb unloading rodent model: technical aspects  

NASA Technical Reports Server (NTRS)

Since its inception at the National Aeronautics and Space Administration (NASA) Ames Research Center in the mid-1970s, many laboratories around the world have used the rat hindlimb unloading model to simulate weightlessness and to study various aspects of musculoskeletal loading. In this model, the hindlimbs of rodents are elevated to produce a 30 degrees head-down tilt, which results in a cephalad fluid shift and avoids weightbearing by the hindquarters. Although several reviews have described scientific results obtained with this model, this is the first review to focus on the technical aspects of hindlimb unloading. This review includes a history of the technique, a brief comparison with spaceflight data, technical details, extension of the model to mice, and other important technical considerations (e.g., housing, room temperature, unloading angle, the potential need for multiple control groups, age, body weight, the use of the forelimb tissues as internal controls, and when to remove animals from experiments). This paper is intended as a reference for researchers, reviewers of manuscripts, and institutional animal care and use committees. Over 800 references, related to the hindlimb unloading model, can be accessed via the electronic version of this article.

Morey-Holton, Emily R.; Globus, Ruth K.

2002-01-01

109

Utility of Recycled Bedding for Laboratory Rodents  

PubMed Central

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

2009-01-01

110

Metallophilic macrophages of the rodent thymus.  

PubMed

For a very long time, we studied the metallophilic macrophages of the rodent thymus and in this review our results on morphological, histochemical, enzymehistochemical, immunohistochemical, ultrastructural and functional features of these cells, as well as the molecular regulation of their development, will be presented. Furthermore, the differences between species will also be discussed and the comparisons with similar/related cell types (metallophilic macrophages in the marginal sinus of the spleen, subcapsular sinus of the lymph nodes and germinal centers of secondary lymphoid follicles) will be made. Metallophilic macrophages are strategically positioned in the thymic cortico-medullary zone and are very likely to be involved in: (i) the metabolism, synthesis and production of bioactive lipids, most likely arachidonic acid metabolites, based on their histochemical and enzymehistochemical features, and (ii) the process of negative selection that occurs in the thymus, based on their ultrastructural features and their reactivity after the application of toxic or immunosuppressive/immunomodulatory agents. Taken together, their phenotypic and functional features strongly suggest that metallophilic macrophages play a significant role in the thymic physiology. PMID:23352337

Mili?evi?, Novica M; Mili?evi?, Živana

2013-03-01

111

UNCORRECTEDPROOF Tropical Margins  

E-print Network

., 2002; Algar et al., 2006) and hydrological and bio- geochemical cycling speeds observed in the equato al., 1994). The cycling of water among the land, sea and atmosphere in the tropics is a major driving climate around the world, as well as ecosystem services to global health and human food harvests (Sun et

Benitez-Nelson, Claudia

112

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 -.

113

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

114

Assessing Tropical Cyclone Damage  

NASA Astrophysics Data System (ADS)

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

Done, J.; Czajkowski, J.

2012-12-01

115

[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

116

Ectoparasites of Rodents Captured in Bandar Abbas, Southern Iran  

PubMed Central

Background: Rodents play important role as host of ectoparasites and reservoir of different zoonotic diseases. The aim of this study was to asses the infestation of commensal rodents with ectoparasites in Bandar Abbas, a port city located in the northern part of the Persian Gulf in Iran. Methods: Rodents were captured using live traps during the study period in year 2007. After transferring the rodents to the laboratory, they were identified and then their ectoparasites were collected and mounted for species identification using appropriate systematic keys. Results: A total of 77 rodents were identified including Rattus norvegicus (74%), R. rattus (16.9%), Mus musculus (7.8%) and one hamster. Among all rodents, 40.3% were found infested with ectoparasites. A total of 69 ectoparasites were collected comprising flea, lice, mite and tick. Two species of fleas; Xenopsylla cheopis and X. astia were identified with higher index of X. astia. Two genera of ticks including Hyalomma sp. and Rhipicephalus sp. were identified. Laelaps nuttalli was the only mite found. The Polyplax spinulosa was considered as lice ectoparasite. Conclusion: Among all arthropods collected, flea and lice had the most and the least frequency, respectively. Nearly all rodent species were infested with Xenopsylla. These fleas are important due to their role in plague and murine typhus transmission. Ticks are important due to their role in CCHF (Crimean-Congo Hemorrhagic Fever), theileriosis, babesiosis, anaplasmosis and ehrlichiosis transmission .Monitoring of ectoparaiste infestation is important for preparedness and early warning preparation for possible control of arthropod-borne diseases. PMID:22808381

Kia, EB; Moghddas-Sani, H; Hassanpoor, H; Vatandoost, H; Zahabiun, F; Akhavan, AA; Hanafi-Bojd, AA; Telmadarraiy, Z

2009-01-01

117

Interval eigenproblem in tropical and fuzzy algebra Tolerance eigenproblem in tropical algebra  

E-print Network

Interval eigenproblem in tropical and fuzzy algebra Tolerance eigenproblem in tropical algebra Tolerance eigenproblem in fuzzy algebra Tolerance interval eigenvectors in tropical and fuzzy algebra Martin Workshop Birmingham, May 16, 2013 #12;Interval eigenproblem in tropical and fuzzy algebra Tolerance

Mitchener, Paul

118

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.

119

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. PMID:14178027

Roelsgaard, E.; Iversen, E.; Bløcher, C.

1964-01-01

120

Tropical ecotoxicology: The state of the environment in the tropics  

SciTech Connect

Ecotoxicology has focused almost exclusively on temperate zone countries and ecosystems. Tropical ecosystems, including rain forest, tropical dry forest, savanna, wetlands and freshwater ecosystems, have been neglected. These ecosystems combined might contain as much as 75% of global biodiversity. Tropical ecosystems are under increasing threat of development and alteration. The major causes of habitat degradation in the tropics include population growth and urbanization, agricultural expansion, deforestation, and mining. Some of these activities (in particular agriculture, mining, and the manufacturing and chemical industries) also lead to the release of toxic substances into the environment. Little research in ecotoxicology has been done in tropical environments and techniques and procedures developed for temperate environments are often applied, even though physical and chemical environmental parameters in the tropics can be very different. The regulatory environment also varies from country to country. The authors present an extensive literature review of tropical ecotoxicology, with a focus on Latin America and the Caribbean. Most research has focused on water quality and aquatic toxicology. Virtually no research has been done on the effects of toxic substance on tropical wildlife. They present a protocol for tropical ecotoxicology that addresses the special problems associated with doing ecotoxicological research in the tropics. The authors discuss the issue of adapting temperate zone principles and methods to tropical environments. Finally, they discuss priority areas for immediate research. These include large scale agricultural activities, especially bananas, pineapples, and soybeans and gold mining with the associated heavy use of mercury. The authors also present a prioritization of tropical wildlife that appear to be at highest risk of exposure to toxic substances.

Lacher, T.E. Jr. [Archbold Tropical Research Center, Clemson, SC (United States); [Inst. of Wildlife and Environmental Toxicology, Pendleton, SC (United States); Goldstein, M.I. [Inst. of Wildlife and Environmental Toxicology, Pendleton, SC (United States)

1995-12-31

121

Tropical Cyclone Eye Thermodynamics  

Microsoft Academic Search

In intense tropical cyclones, sea level pressures at the center are 50-100 hPa lower than outside the vortex, but only 10-30 hPa of the total pressure fall occurs inside the eye between the eyewall and the center. Warming by dry subsidence accounts for this fraction of the total hydrostatic pressure fall. Convection in the eyewall causes the warming by doing

H. E. Willoughby

1998-01-01

122

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

123

Tropical fevers: Management guidelines.  

PubMed

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

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

2014-02-01

124

[Diabetogenic tropical pancreatitis].  

PubMed

The tropical calcifying pancreatitis and/or fibrous pancreatitis are responsible for a number of cases of juvenile insulin-dependent diabetes in the Third World countries. World wide distributed in the tropical areas of Asia, Africa and South America, they can also be observed in Europe, in migrants from these countries. Intensive epidemiological and biochemical studies are currently developed in order to shed light on the many obscure points. Classification of the typical calcifying pancreatitis and the related syndromes is a matter of debate. The pathological basis is calcification of the pancreas and echography of the gland may become a cheap convenient relatively specific tool for epidemiology. The clinical syndrome consists of chronic painful pancreatic episodes since childhood, associated with pancreatic exocrine insufficiency, followed by the onset, during adolescence, of diabetes mellitus, which is most of the times insulin dependent. Patients' history is free of chronic alcoholism, but includes constantly chronic caloric and proteic malnutrition. Although insulin dependent this diabetes in not prone to ketosis, due presumably to carnitine deficiency and relative glucagon deficiency (or suppressibility). Insulin resistance is traditionally noted, the pathophysiology of which is unknown. The mechanism of calcification appearance is also undetermined. Either a deficiency in pancreatic stone protein, or the toxic effect of cyanogen glucosides present in cassava and other tropical foodstuffs, or the malnutrition-related deficiency in sulphur-containing aminoacids may be causal factors. No valid experimental model of the disease is available. PMID:3044866

Assan, R; Assan, D; Thiebaut, M F; Laloux, S; Clauser, E; Boukersi, A

1988-01-01

125

Tropical fevers: Management guidelines  

PubMed Central

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

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

2014-01-01

126

Geographical distribution of rodent-associated hantaviruses in Texas.  

PubMed

The purpose of this study was to increase our knowledge of the geographic distribution and natural host range of hantaviruses in Texas, southeastern New Mexico, and Mexico. Blood samples from 3,225 wild rodents, representing 34 species, were tested for hantavirus antibody (IgG), using an enzyme-linked immunosorbent assay. Hantavirus antibody was found in one or more rodents from each of 13 counties in Texas, Otero County in southeastern New Mexico, and Mexico State (central Mexico). The 133 antibody-positive rodents included seven Peromyscus species (P. attwateri, P. boylii, P. hylocetes, P. leucopus, P. maniculatis, P. melanotis, and P. pectoralis), Sigmodon hispidus, Oryzomys palustris, two Reithrodontomys species (R. fulvescens and R. megalotis), Neotoma albigula, and Perognathus merriami. This study provides further evidence that rodent-associated hantaviruses are geographically widely distributed in Texas. The discovery of antibody in P. hylocetes and P. melanotis is evidence that peromyscine rodents in Mexico are naturally associated with viruses belonging to the genus Hantavirus. PMID:11469186

Mantooth, S J; Milazzo, M L; Bradley, R D; Hice, C L; Ceballos, G; Tesh, R B; Fulhorst, C F

2001-06-01

127

Old World hantaviruses in rodents in New Orleans, Louisiana.  

PubMed

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

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

2014-05-01

128

Comparative study of pig-rodent somatic cell hybrids.  

PubMed

The pig chromosome complement of six different types of pig-rodent hybrid cell lines was examined by means of fluorescence in situ hybridization with a porcine SINE probe. The cell lines were obtained by fusing pig lymphocytes with cells of the Chinese hamster cell lines wg3h, BK14-150 and E36, and of the mouse cell lines NSO, PU and LMTK-. The hybrids were analysed with respect to: (1) the number of pig chromosomes, (2) the type of pig chromosomes, (3) the occurrence of pig-rodent chromosome translocations, and (4) the presence of pig chromosome fragments. The results show that the number of pig chromosomes varied within and among hybrid cell lines. The pig-hamster hybrids mainly retained nontelocentric pig chromosomes, whereas the pig-mouse hybrids also retained telocentric pig chromosomes. Pig-rodent chromosome translocations were found in all types of hybrids, but the incidence was in general low. Chromosome fragments were abundant in BK14-150 hybrids, and rare in most other hybrid cell lines. It is concluded that the SINE probe is a useful tool to make a preliminary characterization of the porcine chromosome complement of pig-rodent somatic cell hybrids. The results of this characterization can be used to select hybrids for further cytogenetic analysis. Furthermore, our data show that different rodent cell lines will have to be used as fusion partners for the production of hybrids when constructing a panel informative for all pig chromosomes. PMID:7818166

Zijlstra, C; Bosma, A A; de Haan, N A

1994-10-01

129

Hypergravity Effects on Rodent Pregnancy and Parturition  

NASA Technical Reports Server (NTRS)

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

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

2002-01-01

130

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. PMID:19424861

Bozzella, Michael J.; Seluanov, Andrei

2008-01-01

131

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

132

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. PMID:22305769

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

2012-01-01

133

Can shrub cover increase predation risk for a desert rodent?  

USGS Publications Warehouse

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

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

1996-01-01

134

Synanthropic rodents as possible reservoirs of shigatoxigenic Escherichia coli strains.  

PubMed

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. PMID:23125967

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

2012-01-01

135

Multiple infections of rodents with zoonotic pathogens in Austria.  

PubMed

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

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

2014-07-01

136

Aerobic and anaerobic metabolism during activity in small rodents.  

PubMed

Analysis of oxygen consumption and lactic acid formation during five minutes of maximal activity by the rodents Microtus montanus (Cricetidae) and Dipodomys merriami (Hetermyidae) indicates that: (1) anaerobiosis provides approximately 10% of total energy utilized during the 5-minute activity period; (2) anaerobiosis may account for as much as one-third of total energy utilized during the first 30 seconds of activity. In addition, these data indicate at least one species of lizard may be capable of a higher total rate of metabolism during "burst" activity than are the rodents investigated here. PMID:381568

Ruben, J A; Battalia, D E

1979-04-01

137

Collection and preparation of rodent embryonic samples for transcriptome study.  

PubMed

The need for large-scale collection of rodent embryos and individual embryonic tissues for genomic and proteomic studies requires modification of traditional practices of embryo necropsy. The sample intended for transcriptome study should be rapidly dissected and stabilized to preserve its molecular integrity. The retrieval of high-quality RNA, DNA, and proteins from the target tissue is crucial for informative molecular analysis (e.g., gene profiling on microarray platform). We present a reliable method of collection and preparation of rodent embryos for genomic studies supported by detailed protocols and RNA extraction results for different stages of mouse embryonic development. PMID:24318829

Golubeva, Yelena; Symer, David

2014-01-01

138

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. PMID:19801795

Johnson, Ryan

2009-01-01

139

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

140

Neighbourhood analyses of tree seed predation by introduced rodents in a New Zealand temperate rainforest  

E-print Network

mice Mus musculus and other introduced rodents represent a novel source of predation on tree seeds have important implications for tree population dynamics. Introduced rodents Á house mice Mus musculus

141

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

142

Tropical Cyclone Intensity Analysis  

NSDL National Science Digital Library

This lesson provides guidance for operational forecasters needing to combine different intensity methods to determine the intensity of a tropical cyclone. Each of the intensity methods is summarized, focusing on both strengths and weaknesses. These methods include the Dvorak technique, surface observations, scatterometry, the Advanced Dvorak Technique (ADT), microwave sounders (AMSU), SATCON, and subjective interpretation of passive microwave patterns. Consideration of the previous intensity estimate and forecast is also examined. Three case studies task the learner with combining the various methods to derive appropriate intensity estimates and a final quiz tests learner knowledge to demonstrate successful completion of the lesson.

Comet

2014-05-15

143

Tropical Fish Rescue  

NSDL National Science Digital Library

Millions of fish eggs from the Caribbean get stuck in the gulf stream every year and drift thousands of miles north where they hatch. Unfortunately, when winter comes, the baby fish will die. In this video, Jonathan joins the New England Aquarium Dive Club on a tropical fish rescue in Rhode Island where they catch some of these fish in the fall before water temperatures plummet. The fish go to the New England Aquariumâs exhibits. Please see the accompanying study guide for educational objectives and discussion points.

Productions, Jonathan B.

2010-02-01

144

HLA and tropical sprue.  

PubMed

In 27 Puerto Rican patients with tropical sprue proven by intestinal biopsy and clinical response to folic acid, HLA type was determined with a microcytotoxicity assay. 25 of these patients had at least one antigen of the Aw-19 series (p = 10(-10)). The strongest association was with Aw-31, for which the relative risk was 10.6 (p = 1.2 X 10(-6)). The absence of a B-locus or haplotype effect suggests a marker association only, rather than an immune association. PMID:2877326

Menendez-Corrada, R; Nettleship, E; Santiago-Delpin, E A

1986-11-22

145

Hurricanes and Tropical Meteorology Background  

E-print Network

- 1 - Hurricanes and Tropical Meteorology Background: Over the last 20 years, hurricane research at AOML has focused on improved scientific understanding of hurricanes and of tropical meteorology scientific goals for AOMLs hurricane research derive from the U.S. Weather Research Programs (USWRP

146

Combating tropical deforestation in Haiti  

SciTech Connect

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

Pellek, R.

1990-09-01

147

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

148

Managing the Tropical Agriculture Revolution  

Microsoft Academic Search

Industrial production of beef, soybeans, cotton, and biofuels is expanding into the tropical latitudes of South America and may soon reach tropical Africa in the most important agricultural transition since the Green Revolution. This shift is driven by the shortage of land suitable for expansion of cultivation and grazing in the temperate zone, increased global demands for agricultural commodities, the

Daniel C. Nepstad; Claudia M. Stickler

2008-01-01

149

Combating tropical deforestation in Haiti  

Microsoft Academic Search

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

Pellek

1990-01-01

150

ENSO and Tropical Cyclone Activity  

Microsoft Academic Search

The present state of knowledge regarding tropical cyclone activity in various ocean basins and the El Niño-Southern Oscillation phenomenon is reviewed in this chapter. The ocean basins include the western North Pacific, the eastern and central North Pacific, the southwestern Pacific, the southeastern Pacific, and the North Atlantic. Following a description of the ENSO phenomenon, tropical cyclone activity in each

Pao-Shin Chu

151

Tropical Underdevelopment Jeffrey D. Sachs  

E-print Network

international effort to develop health and agricultural technologies specific to the needs of the tropical economies. Keywords: economic growth, geography of development, health, agriculture, technological change, and Oceania ­ are outside of the tropics. 1 In the World Development Report 2000/2001 the World Bank defines

152

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

153

Simple models of tropical plumes  

E-print Network

Tropical plumes are upper and mid-level cloud bands at least 2000 km long that cross 15' latitude. The simplest conditions that lead to tropical plume development are sought in a barotropic model simulating winter 200 mb flow. The features sought...

Carrie, Gordon David, d 1960-

2012-06-07

154

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

155

Rodent Pest Control Through the Reintroduction of an Extirpated Raptor Species  

Microsoft Academic Search

Zoos, by nature, are breeding grounds for high numbers of rodents. The use of poisons and traps has been the main tool for rodent control. By acquiring and reintroducing avian predators, specifically barn owls, into a zoo setting, the rodent population could be controlled naturally. Barn owls (Tyto alba) once flourished in Pennsylvania and surrounding areas, particularly in old wooden

Kathryn Antkowiak; Thomas Hayes

156

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

157

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

158

Tropical Synoptic Meteorology Curriculum Package  

NSDL National Science Digital Library

The Tropical Synoptic Meteorology Curriculum Package is a university-level, online meteorology course package. It is freely available to interested institutions that are expanding their course offerings, particularly their online offerings. The course fulfills the synoptic and mesoscale meteorology requirements for the World Meteorological Organization (WMO) Basic Instruction Package for Meteorology (BIP-M), but with an emphasis on the tropics to provide focus for those working or planning to work in tropical regions. The course utilizes existing and newly developed resources, including the online textbook, Introduction to Tropical Meteorology (http://www.meted.ucar.edu/tropical/textbook_2nd_edition/). The course package includes an instructorâs guide and model syllabus with learning objectives, free online instructional resources, introductory slides for faculty use, case examples, questions for review or discussion, student assignments, quizzes, learning activities, and guidance for online course delivery. All materials are made available in Google Docs format for downloading and customizing.

Comet

2013-08-06

159

Leptospira spp. in Rodents and Shrews in Germany  

PubMed Central

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

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

2014-01-01

160

Rodent Models of Alcoholic Liver Disease: Of Mice and Men  

PubMed Central

Alcoholic liver disease (ALD) is a major cause of acute and chronic liver disease worldwide. The progressive nature of ALD is well described however the complex interactions under which these pathologies evolve remain to be fully elucidated. Clinically there are no clear biomarkers or universally accepted, effective treatment strategies for ALD. Experimental models of ALD are an important component in identifying underlying mechanisms of alcohol-induced injury to develop better diagnostic markers, predictors of disease progression, and therapeutic targets to manage, halt, or reverse disease progression. Rodents remain the most accessible model for studying ALD pathology. Effective rodent models must mimic the natural history of ALD while allowing examination of complex interactions between multiple hepatic, and non-hepatic, cell types in the setting of altered metabolic or oxidative/nitrosative stress, inflammatory responses, and sensitivity to cytotoxic stress. Additionally, mode and duration of alcohol delivery influences hepatic response and presents unique challenges in understanding disease pathology. This review provides an overview of rodent models of ALD, their strengths and weaknesses relative to human disease states, and provides insight of the potential to develop novel rodent models to simulate the course of human ALD. PMID:22960051

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

2012-01-01

161

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

162

Rodent Model for Forelimb Neuromuscular Stimulation Based Movement Therapy  

Microsoft Academic Search

We present the development of a novel rodent model for neuromuscular stimulation assisted forelimb movement. The motor points for flexors and extensors of the shoulder, elbow, and digits were identified and the muscles were implanted with custom intramuscular stimulation electrodes. Strength-duration curves were generated to guide the choice of stimulation parameters required to produce consistent isolated contraction of each muscle

Tsukasa Kanchiku; James V Lynskey; Toshihiko Taguchi; James J. Abbas

163

Octodon degus: A Diurnal, Social, and Long-lived Rodent  

Microsoft Academic Search

Octodon degus is a moderate-sized, precocious, but slowly maturing, hystricomorph rodent from central Chile. We have used this species to study a variety of questions about circadian rhythms in a diurnal mammal that readily adapts to most laboratory settings. In collaboration with others, we have found that a number of fundamental features of circa- dian function differ in this diurnal

Theresa M. Lee

164

Visual adaptations in a diurnal rodent, Octodon degus  

Microsoft Academic Search

The degu (Octodon degus) is a diurnal rodent, native to Chile. Basic features of vision and visual organization in this species were examined in a series of anatomical, electrophysiological and behavioral experiments. The lens of the degu eye selectively absorbs short-wavelength light and shows a progressive increase in optical density as a function of age. Electroretinograms recorded using a flicker-photometric

G. H. Jacobs; J. B. Calderone; J. A. Fenwick; K. Krogh; G. A. Williams

2003-01-01

165

Leptospira spp. in rodents and shrews in Germany.  

PubMed

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

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

2014-08-01

166

Haplosporangium in an Additional Rodent Host, Microtus pennsylvanicus Drummondi  

Microsoft Academic Search

SINCE 1942 1, there has been an increase in the number of reports on haplomycosis in rodents and other animals trapped in the United States, Canada and England. Two recent reports from Canada and Sweden describing further isolations of the causative organism Haplosporangium were those published by Bakerspigel2 and Jellison3.

A. Bakerspigel

1957-01-01

167

Temporal changes in a Chihuahuan Desert rodent community  

Microsoft Academic Search

We used time series analysis of ten years of monthly census data to assess the responses of both individual species and an entire community of rodents to a fluctu- ating desert environment. Autocorrelation analysis revealed different patterns of intra-annual fluctuation among the It species: Dipodomys spectabilis and Perog- nathus Jarus had pronounced annual cycles: D. ordii, D. merriaini, Chaetodipus penicillutu~,

James H. Brown; Edward J. Heske

1990-01-01

168

A mechanism for resource allocation among sympatric heteromyid rodent species  

Microsoft Academic Search

Laboratory feeding experiments were conducted with Dipodomys ordii and Perognathus flavus in an attempt to discover a mechanism which might result in seed size selection. There was no marked difference in the proportions of four seed types collected whether the rodents foraged in the presence or absence of one another. However, analysis of the variability in weight of each of

Richard L. Hutto

1978-01-01

169

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...

170

Circuit Dynamics and Coding Strategies in Rodent Somatosensory Cortex  

E-print Network

. BRUMBERG,2 AND DANIEL J. SIMONS2 1 Department of Mathematics, University of Pittsburgh; and 2 Department., Joshua C. Brumberg, and Daniel J. Simons. Circuit dynamics and coding strategies in rodent somatosensory that briefly withstands the strong damping effects of inhib- itory circuitry. To test this experimentally, we

Simons, Dan

171

Evaluation of two oral baiting systems for wild rodents.  

PubMed

Tetracycline hydrochloride (TC)-treated peanut butter or rodent chow baits were distributed during March 1990, on separate 0.53 ha sites in Oglethorpe County, Georgia (USA). Rodents were trapped on a control site prior to bait distribution and on two baited sites 6 days post-distribution. Cleaned skulls from euthanized mammals were grossly examined for TC fluorescence using an ultraviolet (UV) light. Mandibles were sectioned and examined for TC fluorescence using an ultraviolet light microscope. All 21 cotton rats (Sigmodon hispidus), four eastern harvest mice (Rithrodontomys humulis), and two golden mice (Ochrotomys nuttalli) captured on the control site were negative for TC fluorescence. On the peanut butter bait site, mandible sections from 29 of 32 (91%) cotton rats, three of three (100%) eastern harvest mice, two of three (66%) golden mice, zero of five (0%) white-footed mice (Peromyscus leucopus), one of three (33%) short-tailed shrews (Blarina brevicauda), and zero of two (0%) least shrews (Cryptotis parva) were positive for TC. Results from the rodent chow bait site indicated that 18 of 25 (72%) cotton rats, zero of three (0%) eastern harvest mice, two of seven (29%) golden mice, zero of four (0%) white-footed mice, and zero of four (0%) least shrews were positive for TC fluorescence in mandible sections. These results suggest that a large portion of a free-ranging small rodent population can be administered biological markers or vaccines using baits. PMID:9577787

Creekmore, T E; Fletcher, W O; Stallknecht, D E

1998-04-01

172

[Tropical medicine consultation].  

PubMed

Tropical medicine consultations are fully justified in settings with the latest modern technology, where specific complementary tests are available and there are professionals with experience in tropical questions. That is to say, in tertiary hospitals. If such consultations took place in secondary hospitals or in primary care, they could be considered inefficient or unjustifiable from the point of view of the volume of patients attended to. However, there is a care deficit with respect to preventive activities concerning travellers or immigrants who have recently arrived from countries with a low income and where there is a high prevalence of imported diseases that are less recognised in our normal health milieu. Thus, international health units, which combine preventive and curative activities in a framework of public health provision and in a functional situation between the hospital level and that of primary care, offer a more efficient and suitable profile for the characteristics of the Spanish population. Their implementation depends on policy makers, the offer of a realistic portfolio of services, the existence of quality control monitoring and the possibility of managing information through a computer network. PMID:16721420

Valerio, L; de Balanzó, X

2006-01-01

173

Bartonella species in invasive rats and indigenous rodents from Uganda.  

PubMed

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

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

2014-03-01

174

The energetics of a Malagasy rodent, Macrotarsomys ingens (Nesomyinae): a test of island and zoogeographical effects on metabolism.  

PubMed

This study provides first insights into the energetics of the Nesomyinae, a subfamily of rodents endemic to Madagascar. The ancestral nesomyine colonized Madagascar from Africa ca. 30-15 mya at the onset of Oligocene global cooling. We tested the hypothesis that, contrary to what might be expected from Island Biogeography theory, post-colonization character displacement of thermoregulatory traits was constrained by phylogenetic inertia through climate adaptation. The study was conducted in the Parc National d'Ankarafantsika, Madagascar. We measured the basal metabolic rate (BMR) and body temperature (T b) patterns of naturally warm-acclimated, freshly captured adult long-tailed big-footed mice Macrotarsomys ingens (67.4 g). The mean ± SD BMR of M. ingens was 0.298 ± 0.032 Watts (n = 12), 31.7 % lower than that predicted by a phylogenetically independent allometric equation. Body mass was correlated with BMR. The lower critical limit of thermoneutrality (T lc) was 30.7 °C. The mean ± SD T b = 36.1 ± 0.8 °C (n = 12) compared well with the mean T b values for myomorph rodents from the Afrotropical zone, but was lower than those of the Neotropical and Palearctic zones. M. ingens became pathologically hypothermic when exposed to ambient temperatures lower than 18 °C. The soil temperature at depths of 250 mm and deeper did not decrease below 22 °C throughout the austral winter. The thermoregulatory data for M. ingens did not differ from those that characterize mainland Afrotropical rodents. However, BMR and T b were lower than those of Holarctic rodents. Thus, contrary to expectations of Island Biogeography theory that rapid character displacement often occurs in morphological and behavioural traits when mammals colonize islands, M. ingens displayed climate-related physiological traits indicative of phylogenetic inertia. Presumably the tropical conditions that prevailed on Madagascar at the time of colonisation differed very little from those of the African mainland, and hence there was no strong driving force for change. Unlike small tenrecs and lemurs that radiated on Madagascar prior to the Oligocene, traits associated with an insular existence, such as daily torpor and hibernation, were not evident in M. ingens. PMID:25189668

Lobban, Kerileigh D; Lovegrove, Barry G; Rakotondravony, Daniel

2014-12-01

175

CHEMICAL AND RADIATION LEUKEMOGENESIS IN HUMANS AND RODENTS AND THE VALUE OF RODENT MODELS FOR ASSESSING RISKS OF LYMPHOHEMATOPOIETIC CANCERS  

EPA Science Inventory

This report is intended to provide an up-to-date overview of the lymphoid and hematopoietic diseases induced in humans and rodents following exposure to chemical agents. It includes a brief introduction to hematopoiesis and leukemia-inducing agents and their effects in mice and r...

176

Asian Clinical Tropical Medicine Bangkok, Thailand  

E-print Network

Asian Clinical Tropical Medicine Bangkok, Thailand July 21 ­ August 3, 2012 Join the Faculty of Tropical Medicine at Mahidol University, Georgia Health Sciences University, the University of Ottawa, Department of Tropical Hygiene, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand Georgia

Minnesota, University of

177

Copyrighted Material What Is Tropical Ecology?  

E-print Network

Copyrighted Material What Is Tropical Ecology? Asking the question, What is tropical ecology? may seem akin to asking questions such as, Who is buried in Grant's tomb? Tropical ecology is the study of the ecology of tropical regions. But so what? Consider these questions: First, what is ecology? What are its

Landweber, Laura

178

[Neglected tropical diseases - review].  

PubMed

Neglected tropical diseases include a variety of infectious diseases. This review shortly describes the most common diseases. Those infected usually live at a low socioeconomic status and rarely have access to satisfactory health care. The neglected diseases are common and have a high burden of disease. In comparison to HIV, malaria and tuberculosis this group of diseases is in fact neglected. Certain diseases within the group are more neglected than others. Investment for research does not appear to be decided in proportion to burden of disease. Much can be gained by extermination of these diseases. The solution is to integrate improvement of living standards and battling diseases. Iceland has a role to play. PMID:22133523

Kristjansson, Julius; Gudmundsson, Sigurdur

2011-12-01

179

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

PubMed

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

Plenge-Bönig, A; Schmolz, E

2014-05-01

180

Residential indoor humidity control in tropics and sub-tropics  

Microsoft Academic Search

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

MY Chan; SM Deng; XG Xu

2009-01-01

181

Tropical Travel and Skin Infections  

MedlinePLUS

... Media contacts Public service advertisements Stats and facts Gold Triangle Awards Stories and news News releases Press ... Teenage skin Tropical travel Vitamin D Cosmetic treatments Gold Triangle Awards Home Media resources Stats and facts ...

182

Deforestation: Tropical Forests in Decline  

NSDL National Science Digital Library

The Canadian International Development Agency has placed online a draft report entitled "Deforestation: Tropical Forests in Decline." The report examines "the extent of deforestation in developing countries, its causes and consequences, and prospect of more sustainable land use alternatives."

1999-01-01

183

Tropical Storm Lee to Newfoundland  

NASA Video Gallery

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

184

Tropical Cyclones and Climate Change  

E-print Network

Whether the characteristics of tropical cyclones have changed or will change in a warming climate — and if so, how — has been the subject of considerable investigation, often with conflicting results. Large amplitude ...

Knutson, Thomas R.

185

GPM: Hurricanes Beyond the Tropics  

NASA Video Gallery

NASA's Global Precipitation Measurement mission, or GPM, a joint NASA/JAXA mission, will provide rainfall data on storms and hurricanes like Irene that move out of the tropics. The data will be ava...

186

Limitations to adaptive optics image quality in rodent eyes  

PubMed Central

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

Zhou, Xiaolin; Bedggood, Phillip; Metha, Andrew

2012-01-01

187

Susceptibility of selected rodent species from Colorado to Borrelia burgdorferi.  

PubMed

To determine the susceptibility of some common Colorado (USA) rodent species to Borrelia burgdorferi, pregnant Peromyscus maniculatus, Tamias minimus, and Spermophilus lateralis were trapped in May 1990 and kept in quarantine until their young were old enough to be used in the experiment. Six to eight 8-wk-old individuals of each of the Colorado species and, for comparison, eight laboratory raised P. leucopus were subcutaneously inoculated with > or = 10(5) spirochetes in 0.1 ml in July 1990. Tissue specimens were collected for isolation from these animals through April 1991. Spirochetes were isolated from blood, ear, bladder, kidney, spleen, liver, and eye in Barbour-Stoener-Kelly (BSK) medium from P. maniculatus, P. leucopus and T. minimus. Spirochetes were isolated from at least one tissue from all of these animals and no isolations were obtained from any of the S. lateralis. Thus, three of the four rodent species tested are susceptible to, and could harbor, B. burgdorferi. PMID:8722268

Ubico, S R; McLean, R G; Cooksey, L M

1996-04-01

188

Experimental infections by Brucella suis type 4 in Alaskan rodents.  

PubMed

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

Miller, L G; Neiland, K A

1980-10-01

189

A forced-air ventilation system for rodent cages.  

PubMed

A novel forced-air ventilation system for rodent cages was developed. The apparatus was operated at an air flow rate of 56 L/min when used with a 230 mm wide X 450 mm long X 165 mm deep cage. Air velocity measurements in the cage did not exceed 8 m/min at animal (rat) height. The average NH3 concentration in a cage which housed two 250 g rats was less than 0.3 ppm at the end of the third day, whereas the concentration measured in a cage without the forced-air ventilation system was 150 ppm after 3 days. Tests of the water content of soiled bedding showed the forced-air ventilation system to provide a much drier environment for the rodents. PMID:4057945

Wu, D Y; Joiner, G N; McFarland, A R

1985-10-01

190

Anti-epileptogenesis in rodent post-traumatic epilepsy models.  

PubMed

Post-traumatic epilepsy (PTE) accounts for 10-20% of symptomatic epilepsies. The urgency to understand the process of post-traumatic epileptogenesis and search for antiepileptogenic treatments is emphasized by a recent increase in traumatic brain injury (TBI) related to military combat or accidents in the aging population. Recent developments in modeling of PTE in rodents have provided tools for identification of novel drug targets for antiepileptogenesis and biomarkers for predicting the risk of epileptogenesis and treatment efficacy after TBI. Here we review the available data on endophenotypes of humans and rodents with TBI associated with epilepsy. Also, current understanding of the mechanisms and biomarkers for PTE as well as factors associated with preclinical study designs are discussed. Finally, we summarize the attempts to prevent PTE in experimental models. PMID:21402123

Pitkänen, Asla; Bolkvadze, Tamuna; Immonen, Riikka

2011-06-27

191

Challenges in tropical plant nematology.  

PubMed

A major challenge facing agricultural scientists today is the need to secure food for an increasing world population. This growth occurs predominantly in developing, mostly tropical countries, where the majority of hungry people live. Reducing yield losses caused by pathogens of tropical agricultural crops is one measure that can contribute to increased food production. Although plant-parasitic nematodes are often not as important as some other biotic and nonbiotic constraints on crop production in the tropics, they can nevertheless cause extensive damage and substantial yield losses. The effects of agricultural, environmental, socioeconomic, and policy changes on the occurrence of plant-parasitic nematodes in the tropics and the losses these pathogens cause are largely undocumented. Recent developments pose new challenges to tropical nematology. The increased application of molecular diagnostics may widen the knowledge gap between nematologists working in developed countries and in the tropics. Uncertainties concerning the validity of nematode species will lead to practical problems related to quarantine measures and nematode management. The study of interactions between nematodes and other pathogens in disease complexes provide opportunities for multidisciplinary research with scientists from other disciplines but remain underexploited. Difficulties in recognizing emerging nematode threats prevent the timely implementation of management strategies, thus increasing yield losses. Research is needed to address these challenges. Examples are presented mainly but not exclusively from banana, peanut, and rice nematology. PMID:17489690

De Waele, Dirk; Elsen, Annemie

2007-01-01

192

Ventilatory accommodation of changing oxygen demand in sciurid rodents  

Microsoft Academic Search

Ventilation was measured across a range of O2 consumption rates in four sciurid rodents: Tamias minimus (47 g), Spermophilus lateralis (189 g), S. beecheyi (531 g), and Marmota flaviventris juveniles (1054 g) and adults (2989 g). Maximum thermogenic oxygen consumption was measured for all but adult M. flaviventris. Aerobic scopes (maximum\\/minimum O2 consumption rates) were 4.6, 3.8, 5.4, and 4.8

Mark A. Chappell

1992-01-01

193

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

194

Transmission Study of Andes Hantavirus Infection in Wild Sigmodontine Rodents†  

PubMed Central

Our study was designed to contribute to an understanding of the timing and conditions under which transmission of Andes hantavirus in Oligoryzomys longicaudatus reservoir populations takes place. Mice were caged in test habitats consisting of steel drums containing holding cages, where seronegative rodents were exposed to wild seropositive individuals by freely sharing the same cage or being separated by a wire mesh. Tests were also performed for potential viral transmission to mice from excrement-tainted bedding in the cages. Andes virus transmitted efficiently; from 130 attempts with direct contact, 12.3% resulted in virus transmission. However, if we consider only those rodents that proved to be infectious, from 93 attempts we obtained 16 infected animals (17.2%). Twelve of them resulted from intraspecies O. longicaudatus encounters where male mice were differentially affected and 4 resulted from O. longicaudatus to Abrothrix olivaceus. Experiments using Abrothrix longipilis as receptors were not successful. Transmission was not observed between wire mesh-separated animals, and mice were not infected from excrement-tainted bedding. Bites seemed not to be a requisite for oral transmission. Genomic viral RNA was amplified in two out of three saliva samples from seropositive rodents, but it was not detected in urine samples obtained by vesicle puncture from two other infected rodents. Immunohistochemistry, using antibodies against Andes (AND) hantavirus proteins, revealed strong reactions in the lung and salivary glands, supporting the possibility of oral transmission. Our study suggests that AND hantavirus may be principally transmitted via saliva or saliva aerosols rather than via feces and urine. PMID:15479837

Padula, P.; Figueroa, R.; Navarrete, M.; Pizarro, E.; Cadiz, R.; Bellomo, C.; Jofre, C.; Zaror, L.; Rodriguez, E.; Murua, R.

2004-01-01

195

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

196

Seasonal activity patterns of rodents in a sagebrush community  

Microsoft Academic Search

Twelve species of nocturnal rodents were studied on a 2.7-hectare plot of sagebrush desert in west-central Nevada. Six species, Dipodomys merriami, D. ordii, D. panamintinus, D. microps, Onychomys torridus, and Peromyscus maniculatus, were active throughout the year. Four species, Perognathus longimembris, P. formosus, Microdipodops megacephalus, and Reithrodontomys megalotis, hibernated and were active only in spring, summer, and autumn. Onychomys leucogaster

OFarrell

1974-01-01

197

USING SURVIVAL OF RODENTS TO ASSESS QUALITY OF PRAIRIE HABITATS  

Microsoft Academic Search

ABSTRACT—Estimates of abundance,commonly,are used,for assessing quality of wildlife habitat. However, disparities between abundance and fitness parameters make the utility of abundance for predicting quality of habitat questionable. We used survival of rodents and rates of capture to assess quality of habitat in greasewood,scrub and sandhill prairie habitats at the United States Army Pueblo Chemical Depot, Pueblo, Colorado. Only the Ord’s

Robert A. Schorr; Jeremy L. Siemers; Paul M. Lukacs; James P. Gionfriddo; John R. Sovell; Renee J. Rondeau; Michael B. Wunder

2007-01-01

198

PHYLOGENETICS OF THE NEW WORLD RODENT FAMILY HETEROMYIDAE  

Microsoft Academic Search

The family Heteromyidae includes 6 genera of rodents traditionally placed in 3 subfamilies endemic to the Nearctic and northern Neotropical biogeographic regions. Although several of these taxa represent intensively studied members of North and Central American ecosystems (e.g., kangaroo rats and pocket mice), phylogenetic relationships within and among subfamilies, genera, and species-groups are not well understood. Here, we used maximum-likelihood,

Lois F. Alexander; Brett R. Riddle

2005-01-01

199

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

200

Rodent and Ruminant Ingestive Response to Flavonoids in Euphorbia esula  

Microsoft Academic Search

Euphorbia esula, common name leafy spurge, was chemically evaluated for aversive phytochemicals that appear to minimize herbivory by rodents and cattle. A middle-layer extract elicited food aversions in rats as did the petroleum ether extract of the initial methanol extract. Kaempferol-3-0-ß- glucuronic acid and quercetin-3-0-ß-glucuronic acid were separated and identified from the middle-layer residue. This study is the first report

F. Halaweish; S. Kronberg; J. A. Rice

2003-01-01

201

A Functional analysis of circadian pacemakers in nocturnal rodents  

Microsoft Academic Search

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

Serge Daan; Colin S. Pittendrigh

1976-01-01

202

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

203

A functional analysis of circadian pacemakers in nocturnal rodents  

Microsoft Academic Search

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

Serge Daan; Colin S. Pittendrigh

1976-01-01

204

Neural Representation of Spatial Topology in the Rodent Hippocampus  

PubMed Central

Pyramidal cells in the rodent hippocampus often exhibit clear spatial tuning in navigation. Although it has been long suggested that pyramidal cell activity may underlie a topological code rather than a topographic code, it remains unclear whether an abstract spatial topology can be encoded in the ensemble spiking activity of hippocampal place cells. Using a statistical approach developed previously, we investigate this question and related issues in greater details. We recorded ensembles of hippocampal neurons as rodents freely foraged in one and two-dimensional spatial environments, and we used a “decode-to-uncover” strategy to examine the temporally structured patterns embedded in the ensemble spiking activity in the absence of observed spatial correlates during periods of rodent navigation or awake immobility. Specifically, the spatial environment was represented by a finite discrete state space. Trajectories across spatial locations (“states”) were associated with consistent hippocampal ensemble spiking patterns, which were characterized by a state transition matrix. From this state transition matrix, we inferred a topology graph that defined the connectivity in the state space. In both one and two-dimensional environments, the extracted behavior patterns from the rodent hippocampal population codes were compared against randomly shuffled spike data. In contrast to a topographic code, our results support the efficiency of topological coding in the presence of sparse sample size and fuzzy space mapping. This computational approach allows us to quantify the variability of ensemble spiking activity, to examine hippocampal population codes during off-line states, and to quantify the topological complexity of the environment. PMID:24102128

Chen, Zhe; Gomperts, Stephen N.; Yamamoto, Jun; Wilson, Matthew A.

2014-01-01

205

Cycles and travelling waves in rodent dynamics: a comparison  

Microsoft Academic Search

Rodent dynamics was once equated with 3–4 year cycles but is now understood to be many-facetted. In a typology of dynamics,\\u000a including stable and resource-driven populations, extensive cycles and travelling waves appear to have many features in common.\\u000a They differ mainly in the spatial extent of the cycles or waves. Both types of dynamics demonstrate lag phases. Lagged dynamics\\u000a may

Lennart Hansson

2002-01-01

206

Evaluation of Two Oral Baiting Systems for Wild Rodents  

Microsoft Academic Search

of32 (91%) cotton rats, three ofthree (100%) eastern harvest mice, two of three (66%) gold- en mice, zero of five (0%) white-footed mice (Peroniyscus leucopus), one of three (33%) short-tailed shrews (Blarina brevicauda), and zero of two (0%) least shrews (Cnjptotis parva) were positive for TC. Results from the rodent chow bait site indicated that 18 of 25 (72%) cotton

Terry E. Creekmore; David E. Stallknecht

1995-01-01

207

Tropical Cyclone Gonu  

NASA Technical Reports Server (NTRS)

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

2007-01-01

208

Karyotype and reproduction mode of the rodent parasite Strongyloides venezuelensis.  

PubMed

SUMMARY Strongyloides venezuelensis is a parasitic nematode that infects rodents. Although Strongyloides species described to date are known to exhibit parthenogenetic reproduction in the parasitic stage of their life cycle and sexual reproduction in the free-living stage, we did not observe any free-living males in S. venezuelensis in our strain, suggesting that the nematode is likely to depend on parthenogenetic reproduction. We confirmed by cytological analysis that S. venezuelensis produces eggs by parthenogenesis during the parasitic stage of its life cycle. Phylogenetic analysis using nearly the full length of 18S and D3 region of 28S ribosomal RNA gene suggested that S. venezuelensis is distantly related to another rodent parasite, namely Strongyloides ratti, but more closely related to a ruminant parasite, Strongyloides papillosus. Karyotype analysis revealed S. venezuelensis reproduces with mitotic parthenogenesis, and has the same number of chromosomes as S. papillosus (2n = 4), but differs from S. ratti (2n = 6) in this regard. These results, taken together, suggest that S. venezuelensis evolved its parasitism for rodents independently from S. ratti and, therefore, is likely to have a different reproductive strategy. PMID:25089654

Hino, Akina; Tanaka, Teruhisa; Takaishi, Maho; Fujii, Yumiko; Palomares-Rius, Juan E; Hasegawa, Koichi; Maruyama, Haruhiko; Kikuchi, Taisei

2014-11-01

209

A Fully Automated High-Throughput Training System for Rodents  

PubMed Central

Addressing the neural mechanisms underlying complex learned behaviors requires training animals in well-controlled tasks, an often time-consuming and labor-intensive process that can severely limit the feasibility of such studies. To overcome this constraint, we developed a fully computer-controlled general purpose system for high-throughput training of rodents. By standardizing and automating the implementation of predefined training protocols within the animal’s home-cage our system dramatically reduces the efforts involved in animal training while also removing human errors and biases from the process. We deployed this system to train rats in a variety of sensorimotor tasks, achieving learning rates comparable to existing, but more laborious, methods. By incrementally and systematically increasing the difficulty of the task over weeks of training, rats were able to master motor tasks that, in complexity and structure, resemble ones used in primate studies of motor sequence learning. By enabling fully automated training of rodents in a home-cage setting this low-cost and modular system increases the utility of rodents for studying the neural underpinnings of a variety of complex behaviors. PMID:24349451

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

2013-01-01

210

Towards an integrative model of sociality in caviomorph rodents  

PubMed Central

In the late 1990s and early 2000s it was recognized that behavioral ecologists needed to study the sociality of caviomorph rodents (New World hystricognaths) before generalizations about rodent sociality could be made. Researchers identified specific problems facing individuals interested in caviomorph sociality, including a lack of information on the proximate mechanisms of sociality, role of social environment in development, and geographical or intraspecific variation in social systems. Since then researchers have described the social systems of many previously understudied species, including some with broad geographical ranges. Researchers have done a good job of determining the role of social environments in development and identifying the costs and benefits of social living. However, relatively little is known about the proximate mechanisms of social behavior and fitness consequences, limiting progress toward the development of integrative (evolutionary-mechanistic) models for sociality. To develop integrative models behavioral ecologists studying caviomorph rodents must generate information on the fitness consequences of different types of social organization, brain mechanisms, and endocrine substrates of sociality. We review our current understanding and future directions for research in these conceptual areas. A greater understanding of disease ecology, particularly in species carrying Old World parasites, is needed before we can identify potential links between social phenotypes, mechanism, and fitness. PMID:22328791

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

2012-01-01

211

Principles of Rodent Surgery for the New Surgeon  

PubMed Central

For both scientific and animal welfare reasons, training in basic surgical concepts and techniques should be undertaken before ever seeking to perform surgery on a rodent. Students, post-doctoral scholars, and others interested in performing surgery on rodents as part of a research protocol may not have had formal surgical training as part of their required coursework. Surgery itself is a technical skill, and one that will improve with practice. The principles of aseptic technique, however, often remain unexplained or untaught. For most new surgeons, this vital information is presented in piecemeal fashion or learned on the job, neither of which is ideal. It may also make learning how to perform a particular surgery difficult, as the new surgeon is learning both a surgical technique and the principles of asepsis at the same time. This article summarizes and makes recommendations for basic surgical skills and techniques necessary for successful rodent surgery. This article is designed to supplement hands-on training by the user's institution. PMID:21248700

Pritchett-Corning, Kathleen R.; Mulder, Guy B.; Luo, Yiying; White, William J.

2011-01-01

212

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

213

Genotypes of pathogenic Leptospira spp isolated from rodents in Argentina.  

PubMed

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

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

2014-04-01

214

Guidelines for NIH Rodent Transportation 1. The IC Veterinarian or IC Animal Transportation Coordinator is responsible for the oversight of rodent  

E-print Network

1 Guidelines for NIH Rodent Transportation A. General 1. The IC Veterinarian or IC Animal Transportation Coordinator is responsible for the oversight of rodent transportation within their program and assurance that all transportation is handled in accordance with all applicable laws, policies and guidelines

Bandettini, Peter A.

215

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

216

Recognition and management of rodent-borne infectious disease outbreaks after heavy rainfall and flooding.  

PubMed

Climatic events, especially heavy rains and flooding following periods of relative drought, have precipitated both arthropod-borne and rodent-borne infectious disease outbreaks. Heavy rainfall encourages excessive wild grass seed production that supports increased outdoor rodent populations, and flooding forces rodents from their burrows near water sources into the built environment and closer to humans. The objectives of this review are to alert clinicians to the climatic conditions common to hurricane-prone regions, such as Louisiana, that can precipitate outbreaks of the two rodent-borne diseases most often associated with periods of heavy rainfall and flooding, leptospirosis (LS) and hantavirus pulmonary syndrome (HPS). It will also describe the epidemiology, presenting clinical manifestations and outcomes of these rodent-borne infectious diseases, and recommend both prophylactic therapies and effective control and prevention strategies for rodent-borne infectious disease outbreaks. Healthcare providers should maintain high levels of suspicion for LS in patients developing febrile illnesses after contaminated freshwater exposures during flooding or recreational events, and for HPS in patients with febrile illnesses that progress rapidly to respiratory failure following rodent exposures in enclosed spaces. Public health educational strategies should encourage limiting human contact with all wild and peridomestic rats and mice, avoiding all contact with rodent excreta, safely disposing of all rodent excreta, and modifying the built environment to deter rodents from colonizing households and workplaces. PMID:25369218

Diaz, James H

2014-01-01

217

Forest rodents provide directed dispersal of Jeffrey pine seeds.  

PubMed

Some species of animals provide directed dispersal of plant seeds by transporting them nonrandomly to microsites where their chances of producing healthy seedlings are enhanced. We investigated whether this mutualistic interaction occurs between granivorous rodents and Jeffrey pine (Pinus jeffreyi) in the eastern Sierra Nevada by comparing the effectiveness of random abiotic seed dispersal with the dispersal performed by four species of rodents: deer mice (Peromyscus maniculatus), yellow-pine and long-eared chipmunks (Tamias amoenus and T. quadrimaculatus), and golden-mantled ground squirrels (Spermophilus lateralis). We conducted two caching studies using radio-labeled seeds, the first with individual animals in field enclosures and the second with a community of rodents in open forest. We used artificial caches to compare the fates of seeds placed at the range of microsites and depths used by animals with the fates of seeds dispersed abiotically. Finally, we examined the distribution and survival of naturally establishing seedlings over an eight-year period. Several lines of evidence suggested that this community of rodents provided directed dispersal. Animals preferred to cache seeds in microsites that were favorable for emergence or survival of seedlings and avoided caching in microsites in which seedlings fared worst. Seeds buried at depths typical of animal caches (5-25 mm) produced at least five times more seedlings than did seeds on the forest floor. The four species of rodents differed in the quality of dispersal they provided. Small, shallow caches made by deer mice most resembled seeds dispersed by abiotic processes, whereas many of the large caches made by ground squirrels were buried too deeply for successful emergence of seedlings. Chipmunks made the greatest number of caches within the range of depths and microsites favorable for establishment of pine seedlings. Directed dispersal is an important element of the population dynamics of Jeffrey pine, a dominant tree species in the eastern Sierra Nevada. Quantifying the occurrence and dynamics of directed dispersal in this and other cases will contribute to better understanding of mutualistic coevolution of plants and animals and to more effective management of ecosystems in which directed dispersal is a keystone process. PMID:19341138

Briggs, Jennifer S; Vander Wall, Stephen B; Jenkins, Stephen H

2009-03-01

218

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

PubMed

The vomeronasal organ in rodents is an important social and sexual signaling pathway. We have investigated whether the housing of intact immature females in close proximity to mature males would interfere with the sensitivity of the immature rodent uterotrophic bioassay as the result of vomeronasal signals transmitted by male urinary proteins. The hypothesis was that the proximity of males might induce early puberty, thereby increasing mean uterine weight and reducing the responsiveness of the assay. The hypothesis was tested in both rats and mice by housing mature males above immature females, separated only by a wire screen, for 3 days and determining possible changes in uterine weight. The results were negative. Neither the mean uterine weight nor the group mean standard deviation of the uterine weights were changed in the uterotrophic bioassay. Given that the timing of sexual maturation may vary with the strain of mouse used, we also evaluated the sensitivity of the immature mouse uterotrophic assay to diethylstilbestrol (DES) using four strains of mice. Similar sensitivity was observed for the CD-1, C57Bl6, and Alpk strains, but B6CBF(1) mice were marginally less sensitive to DES than were the other strains. These findings add to earlier data indicating the robustness of the rodent uterotrophic assay protocol. PMID:12948899

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

2003-09-01

219

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

PubMed

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

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

2012-04-01

220

Tropical Cyclogenesis in a Tropical Wave Critical Layer: Easterly Waves  

NASA Technical Reports Server (NTRS)

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

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

2009-01-01

221

Podoconiosis, a neglected tropical disease.  

PubMed

Podoconiosis or 'endemic non-filarial elephantiasis' is a tropical disease caused by exposure of bare feet to irritant alkaline clay soils. This causes an asymmetrical swelling of the feet and lower limbs due to lymphoedema. Podoconiosis has a curable pre-elephantiasic phase. However, once elephantiasis is established, podoconiosis persists and may cause lifelong disability. The disease is associated with living in low-income countries in the tropics in regions with high altitude and high seasonal rainfall. It is found in areas of tropical Africa, Central and South America and north-west India. In endemic areas, podoconiosis is a considerable public health problem. Social stigmatisation of patients is widespread and economic losses are enormous since it mainly affects the most productive people, sustaining the disease-poverty-disease cycle. Podoconiosis is unique in being an entirely preventable, non-communicable tropical disease with the potential for eradication. Low-cost preventive measures are a simple but effective solution. However, so far it has received little attention from health care policy makers and, until recently, research into the disease has been scarce and the pathogenesis and genetic basis are partly unclear. A better understanding of these aspects may lead to new prevention and treatment opportunities. In the past few years, several projects fighting podoconiosis have been started by non-governmental organisations. In February 2011, the World Health Organisation designated podoconiosis as one of the 20 neglected tropical diseases, marking an important step in the fight against the disease. PMID:22744921

Korevaar, D A; Visser, B J

2012-06-01

222

Linking human behaviour to environmental effects using a case study of urban rodent control  

Microsoft Academic Search

Pest control is common in many land use activities and can affect non?target species. Our objectives were to evaluate, among chemical rodent control product (rodenticide) users, awareness of non?target effects on wildlife and willingness to change rodent control behaviour given knowledge of possible local non?target effects. Approximately half of respondents to a resident survey in California (USA) practised rodent control;

Anita T. Morzillo; Angela G. Mertig

2011-01-01

223

Ecologically-based rodent management: its effectiveness in cropping systems in South-East Asia  

Microsoft Academic Search

Ecologically-based rodent management (EBRM] has re-emerged as a paradigm for large scale rodent management campaigns. This concept has been tested in replicated, village-scale experiments over 4 years on rodent pests in lowland irrigated rice crops. In Indonesia, villages that practised EBRM had a mean increase in rice yield of 6%, whereas production levels were maintained in Vietnam but control costs

G. R. Singleton; P. R. Brown; J. Jacob

2004-01-01

224

Structure in a desert rodent community: use of space around Dipodomys spectabilis mounds  

Microsoft Academic Search

In an earlier paper (Bowers et al. 1987) we reported patterns of microhabitat use by desert rodents among 0.25-ha plots where seeds were added or certain rodent species removed. We used the results to make inferences about the spatial organization of the whole rodent community. Here we change our focus to test for spatial usage patterns at a smaller (within-plot)

M. A. Bowers; J. H. Brown

1992-01-01

225

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

NSDL National Science Digital Library

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

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

2004-03-09

226

Rodents and their ectoparasites in Wadi Hanifah, Riyadh City, Saudi Arabia.  

PubMed

A survey was conducted on commercial and wild rodents from different locations in Wadi Hanifah in Riyadh. Six species of rodents were collected with wire net traps baited with fresh cucumber or fatty cheese. The trapped rodents in descending order of numbers were Rattus rattus rattus, Acomys dimidiatus, Meriones libycus, R. r. frugivorus, R. r. alexandrinus and Mus musculus. The ectoparasites were a flea, Xenopsyllus sp. on R. r. frugivorus and a tick, Rhipicephalus turanicus on each of A. dimidiatus and R. r. alexandrinus. In general, rodents and ectoparasites were low in Wadi Hanifah, probably due to the severe hot and very dry weather mainly in the summer season. PMID:11775100

Alahmed, A M; Al-Dawood, A S

2001-12-01

227

Multiple Co-infections of Rodents with Hantaviruses, Leptospira, and Babesia in Croatia  

PubMed Central

Abstract Hantaviruses, Leptospira spp., and Babesia spp. are rodent-borne pathogens present worldwide. We studied multiple co-infections of small rodents in Croatia with all three pathogens. Twenty-eight Apodemus flavicollis and 16 Myodes glareolus were tested for the presence of hantavirus RNA by real-time RT-PCR, Leptospira strains by renoculture method and Babesia DNA by PCR. Anti-hantavirus antibodies and anti-Leptospira antibodies were detected by serological methods. Very high infection rates with each pathogen were found in A. flavicollis: 20 of 28 rodents (71%) were infected with Dobrava virus, 13 rodents (46%) were infected with Leptospira, and 5 rodents (18%) were infected with Babesia. Multiple co-infections with all three pathogens were found in 3 of 28 (11%) A. flavicollis animals, suggesting that the same rodent host can be infected with several pathogens at the same time. Dual infections with both hantaviruses and Leptospira were found in 7 of 44 rodents (16%), with hantaviruses and Babesia in 2 rodents (5%), and double infection with both Leptospira and Babesia were found in 1 rodent (2%). Since hantaviruses, Leptospira, and Babesia have similar geographical distributions, it is to be expected that in other parts of the world multiple co-infections, representing a serious threat to public health, can be found. PMID:22217170

Turk, Nenad; Korva, Misa; Margaletic, Josip; Beck, Relja; Vucelja, Marko; Habus, Josipa; Svoboda, Petra; Zupanc, Tatjana Avsic; Henttonen, Heikki; Markotic, Alemka

2012-01-01

228

PHYLOGENETIC RELATIONSHIPS AND DIVERGENCE TIMES IN RODENTS BASED ON BOTH GENES AND FOSSILS.  

E-print Network

??Molecular and paleontological approaches have produced extremely different estimates for divergence times among orders of placental mammals and within rodents with molecular studies suggesting a… (more)

Norris, Ryan

2008-01-01

229

Helminth parasite species richness in rodents from Southeast Asia: role of host species and habitat.  

PubMed

Southeast Asia is a biodiversity hotspot that harbours many species of rodents, including some that live in close contact with humans. They host helminth parasites, some of which are of zoonotic importance. It is therefore important to understand the factors that influence the richness of the helminths parasitizing rodents. The specific objectives of this study were to evaluate rodent species as a factor determining helminth richness in rodent assemblages, to identify the major rodent helminth reservoir species and to explore the influence of habitat on helminth richness. We estimated helminth species richness using a large dataset of 18 rodent species (1,651 individuals) originating from Southeast Asia and screened for helminth parasites. The use of an unbiased estimator shows that the helminth species richness varies substantially among rodent species and across habitats. We confirmed this pattern by investigating the number of helminth species per individual rodent in all rodent species, and specifically in the two mitochondrial lineages Rattus tanezumi and R. tanezumi R3, which were captured in all habitats. PMID:25082015

Palmeirim, Marta; Bordes, Frédéric; Chaisiri, Kittipong; Siribat, Praphaiphat; Ribas, Alexis; Morand, Serge

2014-10-01

230

Studies on the immunobiology of infections with the metacestodes of Echinococcus multilocularis in rodents.  

E-print Network

??The relationships among parasite growth, responses to infection and host genetic factors were examined in rodents infected with Echinococcus multilocularis. Mongolian gerbils, cotton rats and… (more)

Kroeze, Wesley Kars

1987-01-01

231

Satellite Sees Birth of Tropical Storm Gordon  

NASA Video Gallery

An animation of satellite observations from August 13-16, 2012, shows the birth of the Atlantic Ocean hurricane season's eighth tropical depression that strengthens into Tropical Storm Gordon. This...

232

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. ...

233

Tropical Cyclogenesis Factors in a Warming Climate  

E-print Network

Understanding the underlying causes of tropical cyclone formation is crucial to predicting tropical cyclone behavior in a warming environment, given the Earth's current warming trend. This study examines two sets of simulations from the National...

Cathey, Stephen Christopher

2012-02-14

234

Hindawi Publishing Corporation Journal of Tropical Medicine  

E-print Network

Hindawi Publishing Corporation Journal of Tropical Medicine Volume 2012, Article ID 123843, 8 pages, the exact mode of transmission of M. ulcerans remains unclear. #12;2 Journal of Tropical Medicine Buruli

Paris-Sud XI, Université de

235

High Altitude Glaciers in the Tropics  

NSDL National Science Digital Library

While it may seem like a contradiction, glaciers do exist in the tropical latitudes. In this video produced by ThinkTV, learn about tropical glaciers and why scientists are studying them to better understand global climate change.

Thinktv

2010-11-30

236

Tropical Storm Debby Moves into Atlantic  

NASA Video Gallery

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

237

12.811 Tropical Meteorology, Spring 2005  

E-print Network

This course describes the behavior and dynamics of the tropical troposphere, from the large-scale energy balance down to cumulus convection and tropical cyclones. Topics include: Radiative-convective equilibrium; the Hadley ...

Emanuel, Kerry

238

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.

239

Ghrelin Influences Novelty Seeking Behavior in Rodents and Men  

PubMed Central

Recent discoveries indicate an important role for ghrelin in drug and alcohol reward and an ability of ghrelin to regulate mesolimbic dopamine activity. The role of dopamine in novelty seeking, and the association between this trait and drug and alcohol abuse, led us to hypothesize that ghrelin may influence novelty seeking behavior. To test this possibility we applied several complementary rodent models of novelty seeking behavior, i.e. inescapable novelty-induced locomotor activity (NILA), novelty-induced place preference and novel object exploration, in rats subjected to acute ghrelin receptor (growth hormone secretagogue receptor; GHSR) stimulation or blockade. Furthermore we assessed the possible association between polymorphisms in the genes encoding ghrelin and GHSR and novelty seeking behavior in humans. The rodent studies indicate an important role for ghrelin in a wide range of novelty seeking behaviors. Ghrelin-injected rats exhibited a higher preference for a novel environment and increased novel object exploration. Conversely, those with GHSR blockade drastically reduced their preference for a novel environment and displayed decreased NILA. Importantly, the mesolimbic ventral tegmental area selective GHSR blockade was sufficient to reduce the NILA response indicating that the mesolimbic GHSRs might play an important role in the observed novelty responses. Moreover, in untreated animals, a striking positive correlation between NILA and sucrose reward behavior was detected. Two GHSR single nucleotide polymorphisms (SNPs), rs2948694 and rs495225, were significantly associated with the personality trait novelty seeking, as assessed using the Temperament and Character Inventory (TCI), in human subjects. This study provides the first evidence for a role of ghrelin in novelty seeking behavior in animals and humans, and also points to an association between food reward and novelty seeking in rodents. PMID:23227170

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

2012-01-01

240

Unintentional wildlife poisoning and proposals for sustainable management of rodents.  

PubMed

In Europe, bromadiolone, an anticoagulant rodenticide authorized for plant protection, may be applied intensively in fields to control rodents. The high level of poisoning of wildlife that follows such treatments over large areas has been frequently reported. In France, bromadiolone has been used to control water voles (Arvicola terrestris) since the 1980s. Both regulation and practices of rodent control have evolved during the last 15 years to restrict the quantity of poisoned bait used by farmers. This has led to a drastic reduction of the number of cases of poisoned wildlife reported by the French surveillance network SAGIR. During the autumn and winter 2011, favorable weather conditions and high vole densities led to the staging of several hundreds of Red Kites (Milvus milvus) in the Puy-de-Dôme department (central France). At the same time, intensive treatments with bromadiolone were performed in this area. Although no misuse has been mentioned by the authorities following controls, 28 Red Kites and 16 Common Buzzards (Buteo buteo) were found dead during surveys in November and December 2011. For all these birds, poisoning by bromadiolone as the main cause of death was either confirmed or highly suspected. Other observations suggest a possible impact of bromadiolone on the breeding population of Red Kites in this area during the spring 2011. French regulation of vole control for plant protection is currently under revision, and we believe this event calls for more sustainable management of rodent outbreaks. Based on large-scale experiments undertaken in eastern France, we propose that direct control of voles at low density (with trapping or limited chemical treatments) and mechanical destruction of vole tunnels, mole control, landscape management, and predator fostering be included in future regulation because such practices could help resolve conservation and agricultural issues. PMID:24405288

Coeurdassier, Michael; Riols, Romain; Decors, Anouk; Mionnet, Aymeric; David, Fabienne; Quintaine, Thomas; Truchetet, Denis; Scheifler, Renaud; Giraudoux, Patrick

2014-04-01

241

Rodent Models and Behavioral Outcomes of Cervical Spinal Cord Injury  

PubMed Central

Rodent spinal cord injury (SCI) models have been developed to examine functional and physiological deficits after spinal cord injury with the hope that these models will elucidate information about human SCI. Models are needed to examine possible treatments and to understand histopathology after SCI; however, they should be considered carefully and chosen based on the goals of the study being performed. Contusion, compression, transection, and other models exist and have the potential to reveal important information about SCI that may be related to human SCI and the outcomes of treatment and timing of intervention.

Geissler, Sydney A.; Schmidt, Christine E.; Schallert, Timothy

2014-01-01

242

Assessment of rodents as animal models for Reston ebolavirus.  

PubMed

The emergence of Reston ebolavirus (REBOV) in domestic swine in the Philippines has caused a renewed interest in REBOV pathogenicity. Here, the use of different rodent species as animal disease models for REBOV was investigated. BALB/c and STAT1(-)(/-) mice, Hartley guinea pigs, and Syrian hamsters were inoculated intraperitoneally with REBOV strain Pennsylvania or Reston08-A. Although virus replication occurred in guinea pigs, hamsters, and STAT1(-/-) mice, progression to disease was only observed in STAT1(-)(/-) mice. Moreover, REBOV Pennsylvania was more pathogenic than REBOV Reston08-A in this model. Thus, STAT1(-)(/-) mice may be used for research of REBOV pathogenicity and intervention strategies. PMID:21987777

de Wit, Emmie; Munster, Vincent J; Metwally, Samia A; Feldmann, Heinz

2011-11-01

243

Pulmonary Toxicity Studies of Lunar Dusts in Rodents  

NASA Technical Reports Server (NTRS)

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

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

2008-01-01

244

Hemorrhagic gastritis in free-living rodents in Idaho.  

PubMed

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

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

1996-10-01

245

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. PMID:9866729

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

1998-01-01

246

Reflections on the tropical deforestation crisis  

Microsoft Academic Search

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

William F. Laurance

1999-01-01

247

8, 42214266, 2008 Tropical forest fire  

E-print Network

ACPD 8, 4221­4266, 2008 Tropical forest fire emissions R. J. Yokelson et al. Title Page Abstract Chemistry and Physics Discussions The tropical forest and fire emissions experiment: laboratory fire Publications on behalf of the European Geosciences Union. 4221 #12;ACPD 8, 4221­4266, 2008 Tropical forest fire

Paris-Sud XI, Université de

248

The Tropical East Pacific as a Laboratory for Tropical Cyclones  

NASA Astrophysics Data System (ADS)

The summertime tropical cyclogenesis rate per unit area in the eastern Pacific ocean is arguably higher than in any other location in the world. Many if not most of these cyclones form from African easterly waves which cross Central America into the Pacific. Of order 25% of these waves intensify into cyclones. A significant fraction of east Pacific tropical cyclones undergoes landfall on the Mexican coast. Those which do not, generally dissipate over cold ocean waters north of the east Pacific intertropical convergence zone, often not far from land. The layer of warm ocean water which supports the development of east Pacific cyclones is unusually shallow and is structured by anticyclonic vortices which form by various processes and propagate slowly to the west. These vortices locally deepen the oceanic mixed layer and support stronger convection than their surroundings, possibly promoting cyclogenesis and cyclone intensification. Cyclones in turn have an unusually large effect on the ocean mixed layer due to its shallowness. The east Pacific is thus a region of strong coupling between the atmosphere and the ocean, mediated in large part by the action of tropical cyclones. In most cases cyclogenesis, intensification, landfall, and decay over cold water occur within easy range of research aircraft launched from a number of Central American and Mexican bases such as San Jose, Huatulco, Acapulco, Puerto Vallarta, and Cabo San Lucas. The U. S. National Center for Atmospheric Research, the National Oceanic and Atmospheric Administration, and the National Aeronautics and Space Administration have all successfully operated aircraft-based research projects from one or more of these locations. The frequency with which cyclones form, develop, and decay in the east Pacific and their proximity to land bases with excellent facilities make the tropical east Pacific an ideal international laboratory for the study of tropical cyclones. Given the importance of these cyclones to global weather and climate, every effort should be made to take advantage of this natural laboratory to enhance our knowledge of this phenomenon.

Raymond, D. J.

2007-05-01

249

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

PubMed

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

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

2014-05-01

250

The non-genotoxicity to rodents of the potent rodent bladder carcinogens o-anisidine and p-cresidine.  

PubMed

The two potent rodent bladder carcinogens o-anisidine and p-cresidine, and the structurally related non-carcinogen 2,4-dimethoxyaniline, have been extensively evaluated for genotoxicity to rodents and found to be inactive. Most data were generated on o-anisidine, an agent that is also only marginally genotoxic in vitro. The two carcinogens induced methaemoglobinaemia in rodents indicating that the chemicals are absorbed and metabolically oxidized. Despite their total lack of genotoxicity in vivo, the two carcinogens have the hall-marks of being genotoxic carcinogens given that most test animals of both sexes of B6C3F1 mice and F344 rats are reported to have succumbed rapidly to malignant bladder cancer. No reasons for this dramatic conflict of test data are so far apparent. The experiments described involve, in one or other combination, 2 strains of mice (including B6C3F1) and 4 strains of rat (including F344), the use of oral and i.p. routes of exposure and observations made after 1, 3 or 6 doses of test chemical. 6 tissues (including the rat bladder) were assayed using 3 genetic endpoints (unscheduled DNA synthesis, DNA single-strand breaks and micronuclei induction). Aroclor-induced rats were employed in one set of experiments with o-anisidine. In the case of one set of mouse bone-marrow micronucleus experiments the same batch of the 3 chemicals as used in the cancer bioassays, and the same strain of mouse, were used. Possible further experiments and the implications of these findings are discussed. PMID:1719389

Ashby, J; Lefevre, P A; Tinwell, H; Brunborg, G; Schmezer, P; Pool-Zobel, B; Shanu-Wilson, R; Holme, J A; Soderlund, E J; Gulati, D

1991-01-01

251

Integrated Pest Management: Conducting Urban Rodent Surveys i Suggested citation: Centers for Disease Control and Prevention. Integrated pest management: conducting urban  

E-print Network

#12;Integrated Pest Management: Conducting Urban Rodent Surveys i Suggested citation: Centers for Disease Control and Prevention. Integrated pest management: conducting urban rodent surveys. Atlanta: US...........................................................................................................................2 Characteristics of Urban Rodent Surveys

252

6, 74997518, 2006 Tropical analyses  

E-print Network

. The easterly zonal winds were too strong by 2.4 m/s, but this could be explained by the balloon Stokes drift, winds and trajectories in the Southern Hemisphere tropical and midlatitude stratosphere as compared tropopause the ECMWF operational temperatures show a systematic cold bias of 0.9 K and the easterly zonal

Paris-Sud XI, Université de

253

Tropical rainforest biodiversity: field and  

E-print Network

Tropical rainforest biodiversity: field and GIS tools for assessing, monitoring and mapping II with Tanzania National ParksTanzania National Parks andand Wildlife Conservation SocietyWildlife Conservation at the Udzungwa Ecological Monitoring Centre, aUdzungwa Ecological Monitoring Centre, a field station annexed

254

Collective action and tropical deforestation  

Microsoft Academic Search

Views tropical forests as providing a number of outputs for the host country and the world at large. Activities to curb deforestation yield private goods, local (country-specific) public goods, and global public goods. Markets can operate with respect to the private goods, while nations are motivated to strike bargains with one another with respect to the country-specific public goods. Inefficiency

Todd Sandler

1997-01-01

255

Tropical Cyclone Report Hurricane Irene  

E-print Network

Tropical Cyclone Report Hurricane Irene (AL092011) 21-28 August 2011 Lixion A. Avila and John Cangialosi National Hurricane Center 14 December 2011 Updated 19 December 2011 to correct landfall pressure as a category 3 hurricane (on the Saffir-Simpson Hurricane Wind Scale) but gradually weakened after crossing

256

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

257

Tropical forests: The policy challenge  

Microsoft Academic Search

Summary Tropical forests are being destroyed faster than ever, the rate having almost doubled during the 1980s. The main agent of deforestation now turns out to be the displaced peasant or landless farmer, sometimes known as the ‘shifted cultivator’; that group accounts for more forest loss than the combined impacts of the commercial logger, the cattle rancher and all other

Norman Myers

1992-01-01

258

Viral exanthems in the tropics  

Microsoft Academic Search

Viral exanthems are a common problem in tropical regions, particularly affecting children. Most exanthems are transient and harmless, but some are potentially very dangerous. Pregnant women and malnourished or immunocompromised infants carry the greatest risk of adverse outcome. In this article, parvovirus B19; dengue and yellow fever; West Nile, Barmah Forest, Marburg, and Ebola viruses, and human herpesviruses; asymmetric periflexural

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

2007-01-01

259

Tropical Cyclone Report Hurricane Katrina  

E-print Network

1 Tropical Cyclone Report Hurricane Katrina 23-30 August 2005 Richard D. Knabb, Jamie R. Rhome, and damage cost estimates Katrina was an extraordinarily powerful and deadly hurricane that carved a wide deadliest hurricanes to ever strike the United States. Katrina first caused fatalities and damage

260

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

261

Tropical Storm Allison Progression (WMS)  

NSDL National Science Digital Library

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

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

2004-03-11

262

Wind Lidar for Tropical Climatology.  

National Technical Information Service (NTIS)

In the scope of a study for a space mission named BEST (Tropical System Energy Budget) a wind Doppler lidar is investigated. A conical scan and a four fixed telescopes lidar concepts are presented. The four fixed telescopes configuration alleviates the dy...

G. Chalon

1988-01-01

263

Rodent ectoparasites from two locations in northwestern Florida.  

PubMed

From Feb.-Apr. 1999, 19 species of ectoparasitic arthropods (2 sucking lice, 4 fleas, 4 ticks, 2 mesostigmatid mites, 5 chiggers, 2 fur mites) were recovered from 106 rodents belonging to 5 species (cotton mouse, Peromyscus gossypinus, n = 64; cotton rat, Sigmodon hispidus, n = 23; eastern woodrat, Neotoma floridana, n = 9; golden mouse, Ochrotomys nuttalli, n = 9; eastern gray squirrel, Sciurus carolinensis, n = 1) at Tall Timbers Research Station, Leon County, Florida. During the same period, 13 species of ectoparasites (2 sucking lice, 1 flea, 3 ticks, 3 mesostigmatid mites, 2 chiggers, 2 fur mites) were recovered from 57 rodents belonging to 3 species (S. hispidus, n = 40; black rat, Rattus rattus, n = 16; S. carolinensis, n = 1) from Panama City, Bay County, Florida. Noteworthy ectoparasite records include Ixodes minor from both sites, which extends the known geographical range of this tick, and Stenoponia americana from Tall Timbers that represents the second documented Florida record of this flea. Potential tick vectors (Dermacentor variabilis and Ixodes scapularis) of zoonotic pathogens (Rickettsia rickettsii and Borrelia burgdorferi) were collected at both sites. On S. hispidus, fleas were more prevalent at Tall Timbers but sucking lice, chiggers, ticks, mesostigmatid and listrophorid mites all were more prevalent at the Panama City site. Arthropods recovered from arboreal nests (n = 3) of O. nuttalli at Tall Timbers included 3 species of ectoparasites (1 tick, 2 laelapid mites). PMID:11217221

Durden, L A; Hu, R; Oliver, J H; Cilek, J E

2000-12-01

264

Variations in Rodent Models of Type 1 Diabetes: Islet Morphology  

PubMed Central

Type 1 diabetes (T1D) is characterized by hyperglycemia due to lost or damaged islet insulin-producing ?-cells. Rodent models of T1D result in hyperglycemia, but with different forms of islet deterioration. This study focused on 1 toxin-induced and 2 autoimmune rodent models of T1D: BioBreeding Diabetes Resistant rats, nonobese diabetic mice, and Dark Agouti rats treated with streptozotocin. Immunochemistry was used to evaluate the insulin levels in the ?-cells, cell composition, and insulitis. T1D caused complete or significant loss of ?-cells in all animal models, while increasing numbers of ?-cells. Lymphocytic infiltration was noted in and around islets early in the progression of autoimmune diabetes. The loss of lymphocytic infiltration coincided with the absence of ?-cells. In all models, the remaining ?- and ?-cells regrouped by relocating to the islet center. The resulting islets were smaller in size and irregularly shaped. Insulin injections subsequent to induction of toxin-induced diabetes significantly preserved ?-cells and islet morphology. Diabetes in animal models is anatomically heterogeneous and involves important changes in numbers and location of the remaining ?- and ?-cells. Comparisons with human pancreatic sections from healthy and diabetic donors showed similar morphological changes to the diabetic BBDR rat model. PMID:23762878

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

2013-01-01

265

Identification of rodent carcinogens by an expert system.  

PubMed

CASE, an artificial intelligence method for identifying structural determinants responsible for biological activity was applied to the U.S. National Toxicology Program (NTP) cancer bioassay results. CASE identified structures which were significantly associated with rodent carcinogenicity. On the basis of these structural determinants CASE exhibited a sensitivity of 0.98 and a specificity of 1.00. CASE showed a similarly remarkable performance in predicting the carcinogenicity, or lack thereof, of chemicals not in the NTP data base. A comparison between the activating structures (biophores) responsible for mutagenicity in Salmonella and rodent carcinogenicity showed a significant overlap, verifying that there are structural commonalities between the two phenomena. CASE also identified biophores significantly associated with the activity of non-genotoxic carcinogens, thereby suggesting the unexpected possibility that there is a structural commonality among the chemicals included in this group. A comparison between the biophores responsible for carcinogenicity in mice and rats resulted in the identification of common ("universal") biophores. It is suggested that agents which contain "universal" biophores are more likely to present a risk to human than carcinogens that do not possess such biophores. CASE also permitted the recognition of species-specific carcinogenic biophores. While the former are primarily electrophiles or potential electrophiles, the latter represent non-electrophilic structures. PMID:2203007

Rosenkranz, H S; Klopman, G

1990-01-01

266

Chromosomal instability in rodents caused by pollution from Baikonur cosmodrome.  

PubMed

An assessment of the health status of ecosystems exposed to man-made pollution is a vital issue for many countries. Particularly it concerns the consequences of contamination caused by the activity of the space industry. Each rocket launch is accompanied by the introduction of parts of the rocket propellant into the environment. This study aims to scrutinize the effect of the components of rocket fuel on the induction of lipid peroxidation and chromosomal aberrations on rodents inhabiting the area exposed to pollution from Baikonur cosmodrome. The results showed the increase of the level of lipid hydroperoxide and malondialdehyde in the livers of Citellus pygmaeus Pallas and Mus musculus L., which indicates an augmentation of free radical activity and DNA damage. The cytogenetic analysis of bone marrow cells revealed that the frequency of chromosomal aberrations was a few times higher in the rodents from contaminated territory. The signs of oxidative stress and high level of chromosomal aberrations indicate the environmental impact of the cosmodrome, and its possible toxic and mutagenic effects on ecosystems. PMID:24990120

Kolumbayeva, Saule; Begimbetova, Dinara; Shalakhmetova, Tamara; Saliev, Timur; Lovinskaya, Anna; Zhunusbekova, Benazir

2014-09-01

267

Relapsing fever group Borrelia in Southern California rodents.  

PubMed

Wild rodent reservoir host species were surveyed prospectively for infection with Borrelia hermsii, the causative agent of tick-borne relapsing fever in the western United States. Trapping occurred during the summer of 2009-2012 at field sites surrounding Big Bear Lake, CA, a region where human infection has been reported for many years. Using quantitative polymerase chain reaction (qPCR), we tested 207 rodents from 11 species and found chipmunks (Tamias spp.) and a woodrat (Neotoma macrotis) infected. Chipmunks represented the majority of captures at these sites. Sixteen of the 207 (7.7%; CI = 4.6-12.4) animals were qPCR-positive for Borrelia spp. associated with relapsing fever, and of those, we obtained bacterial DNA sequences from eight. The phylogram made from these sequences depict a clear association with B. hermsii genomic group I. In addition, we identified an infection with Borrelia coriaceae in a Tamias merriami, a potentially nonpathogenic member of the tick-borne relapsing fever group. Our findings support the hypothesis that chipmunk species play an important role in the maintenance of Borrelia species that cause tick-borne relapsing fever in the western United States, and therefore the risk of infection to people. PMID:25276933

Nieto, Nathan C; Teglas, Mike B

2014-09-01

268

Studying Autism in Rodent Models: Reconciling Endophenotypes with Comorbidities  

PubMed Central

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.

2013-01-01

269

Hearing in prairie dogs: transition between surface and subterranean rodents.  

PubMed

Behavioral audiograms were determined for four black-tailed and one white-tailed prairie dogs (Cynomys ludovicianus and C. leucurus) using a conditioned avoidance procedure. The hearing of black-tailed prairie dogs ranges from 29 Hz to 26 kHz and that of the white-tailed prairie dog from 44 Hz to 26 kHz (at sound pressure levels of 60 dB). Both species have good low-frequency hearing, especially black-tailed prairie dogs which can hear as low as 4 Hz and are more sensitive than any other rodent yet tested at frequencies below 63 Hz. In contrast, prairie dogs are relatively insensitive in their midrange and have poor high-frequency hearing. It is suggested that the reduced midrange sensitivity and high-frequency hearing are related to their adaptation to an underground lifestyle with its reduced selective pressure for sound localization. In this respect they appear to be intermediate between the more exclusively subterranean rodents (such as gophers and mole rats) and surface dwellers (such as chinchillas and kangaroo rats). PMID:8188546

Heffner, R S; Heffner, H E; Contos, C; Kearns, D

1994-03-01

270

The need for speed in rodent locomotion analyses.  

PubMed

Locomotion analysis is now widely used across many animal species to understand the motor defects in disease, functional recovery following neural injury, and the effectiveness of various treatments. More recently, rodent locomotion analysis has become an increasingly popular method in a diverse range of research. Speed is an inseparable aspect of locomotion that is still not fully understood, and its effects are often not properly incorporated while analyzing data. In this hybrid manuscript, we accomplish three things: (1) review the interaction between speed and locomotion variables in rodent studies, (2) comprehensively analyze the relationship between speed and 162 locomotion variables in a group of 16 wild-type mice using the CatWalk gait analysis system, and (3) develop and test a statistical method in which locomotion variables are analyzed and reported in the context of speed. Notable results include the following: (1) over 90% of variables, reported by CatWalk, were dependent on speed with an average R(2) value of 0.624, (2) most variables were related to speed in a nonlinear manner, (3) current methods of controlling for speed are insufficient, and (4) the linear mixed model is an appropriate and effective statistical method for locomotion analyses that is inclusive of speed-dependent relationships. Given the pervasive dependency of locomotion variables on speed, we maintain that valid conclusions from locomotion analyses cannot be made unless they are analyzed and reported within the context of speed. Anat Rec, 297:1839-1864, 2014. © 2014 Wiley Periodicals, Inc. PMID:24890845

Batka, Richard J; Brown, Todd J; Mcmillan, Kathryn P; Meadows, Rena M; Jones, Kathryn J; Haulcomb, Melissa M

2014-10-01

271

Modelling cognitive affective biases in major depressive disorder using rodents.  

PubMed

Major depressive disorder (MDD) affects more than 10% of the population, although our understanding of the underlying aetiology of the disease and how antidepressant drugs act to remediate symptoms is limited. Major obstacles include the lack of availability of good animal models that replicate aspects of the phenotype and tests to assay depression-like behaviour in non-human species. To date, research in rodents has been dominated by two types of assays designed to test for depression-like behaviour: behavioural despair tests, such as the forced swim test, and measures of anhedonia, such as the sucrose preference test. These tests have shown relatively good predictive validity in terms of antidepressant efficacy, but have limited translational validity. Recent developments in clinical research have revealed that cognitive affective biases (CABs) are a key feature of MDD. Through the development of neuropsychological tests to provide objective measures of CAB in humans, we have the opportunity to use 'reverse translation' to develop and evaluate whether similar methods are suitable for research into MDD using animals. The first example of this approach was reported in 2004 where rodents in a putative negative affective state were shown to exhibit pessimistic choices in a judgement bias task. Subsequent work in both judgement bias tests and a novel affective bias task suggest that these types of assay may provide translational methods for studying MDD using animals. This review considers recent work in this area and the pharmacological and translational validity of these new animal models of CABs. PMID:24467454

Hales, Claire A; Stuart, Sarah A; Anderson, Michael H; Robinson, Emma S J

2014-10-01

272

Genome Diversification Mechanism of Rodent and Lagomorpha Chemokine Genes  

PubMed Central

Chemokines are a large family of small cytokines that are involved in host defence and body homeostasis through recruitment of cells expressing their receptors. Their genes are known to undergo rapid evolution. Therefore, the number and content of chemokine genes can be quite diverse among the different species, making the orthologous relationships often ambiguous even between closely related species. Given that rodents and rabbit are useful experimental models in medicine and drug development, we have deduced the chemokine genes from the genome sequences of several rodent species and rabbit and compared them with those of human and mouse to determine the orthologous relationships. The interspecies differences should be taken into consideration when experimental results from animal models are extrapolated into humans. The chemokine gene lists and their orthologous relationships presented here will be useful for studies using these animal models. Our analysis also enables us to reconstruct possible gene duplication processes that generated the different sets of chemokine genes in these species. PMID:23991422

Shibata, Kanako; Yoshie, Osamu; Tanase, Sumio

2013-01-01

273

Axenic isolation of Giardia strains from primates and rodents.  

PubMed

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

Majewska, A C; Kasprzak, W

1990-02-01

274

Genotoxic evaluation of pirfenidone using erythrocyte rodent micronucleus assay.  

PubMed

Pirfenidone is a non-steroidal antifibrotic compound that has been proposed in clinical protocols and experimental studies as a pharmacological treatment for fibroproliferative diseases. The objective of this study was to determine the genotoxicity or cytotoxicity of three doses of pirfenidone using the micronuclei test in peripheral blood erythrocytes of rodent models. Pirfenidone was administered orally to Balb-C mice for 3 days, and also was administered topically to hairless Sprague Dawley rats during the final stage of gestation. Mice were sampled every 24 h over the course of 6 days; pregnant rats were sampled every 24 h during the last 6 days of gestation, and pups were sampled at birth. Blood smears were analyzed and the frequencies of micronucleated erythrocytes (MNEs), micronucleated polychromatic erythrocytes (MNPCEs), and the proportion of polychromatic erythrocytes (PCEs), were recorded in samples from mice, pregnant rats and rat neonates. Increases in MN frequencies (p<0.03) were noted only in the positive control groups. No genotoxic effects or decreased PCE values were observed neither in newborn rats transplacentally exposed to pirfenidone, or in two adult rodent models when pirfenidone was administered orally or topically. PMID:22683486

Alcántar-Díaz, Blanca E; Gómez-Meda, Belinda C; Zúñiga-González, Guillermo M; Zamora-Perez, Ana L; González-Cuevas, Jaime; Alvarez-Rodríguez, Bertha A; Sánchez-Parada, María Guadalupe; García-Bañuelos, Jesús J; Armendáriz-Borunda, Juan

2012-08-01

275

Visual landmarks facilitate rodent spatial navigation in virtual reality environments.  

PubMed

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. PMID:22345484

Youngstrom, Isaac A; Strowbridge, Ben W

2012-03-01

276

Population ecology of hantavirus rodent hosts in southern Brazil.  

PubMed

In this study we analyze population dynamics of hantavirus rodent hosts and prevalence of infection over a 2-year period in Southern Brazil, a region with a high incidence of hantavirus pulmonary syndrome. The 14 small mammal species captured were composed of 10 rodents and four marsupials, the six most abundant species being Akodon serrensis, Oxymycterus judex, Akodon montensis, Akodon paranaensis, Oligoryzomys nigripes, and Thaptomys nigrita. These species displayed a similar pattern with increasing population sizes in fall/winter caused by recruitment and both, increase in reproductive activity and higher hantavirus prevalence in spring/summer. Specific associations between A. montensis/Jaborá Virus (JABV) and O. nigripes/Juquitiba-like Virus (JUQV-like) and spillover infections between A. paranaensis/JABV, A. serrensis/JABV, and A. paranaensis/JUQV-like were observed. Spillover infection in secondary hosts seems to play an important role in maintaining JABV and JUQV-like in the hantavirus sylvatic cycle mainly during periods of low prevalence in primary hosts. PMID:24935954

Teixeira, Bernardo R; Loureiro, Nathalie; Strecht, Liana; Gentile, Rosana; Oliveira, Renata C; Guterres, Alexandro; Fernandes, Jorlan; Mattos, Luciana H B V; Raboni, Sonia M; Rubio, Giselia; Bonvicino, Cibele R; dos Santos, Claudia N Duarte; Lemos, Elba R S; D'Andrea, Paulo S

2014-08-01

277

Phylogeography of Trichuris populations isolated from different Cricetidae rodents.  

PubMed

The phylogeography of Trichuris populations (Nematoda) collected from Cricetidae rodents (Muroidea) from different geographical regions was studied. Ribosomal DNA (Internal Transcribed Spacers 1 and 2, and mitochondrial DNA (cytochrome c- oxidase subunit 1 partial gene) have been used as molecular markers. The nuclear internal transcribed spacers (ITSs) 1 and 2 showed 2 clear-cut geographical and genetic lineages: one of the Nearctic region (Oregon), although the second was widespread throughout the Palaearctic region and appeared as a star-like structure in the minimum spanning network. The mitochondrial results revealed that T. arvicolae populations from the Palaearctic region were separated into 3 clear-cut geographical and genetic lineages: populations from Northern Europe, populations from Southern (Spain) and Eastern Europe (Croatia, Belarus, Kazahstan), and populations from Italy and France (Eastern Pyrénean Mountains). Phylogenetic analysis obtained on the basis of ITS1-5·8S-ITS2 rDNA sequences did not show a differential geographical structure; however, these markers suggest a new Trichuris species parasitizing Chionomys roberti and Cricetulus barabensis. The mitochondrial results revealed that Trichuris populations from arvicolinae rodents show signals of a post-glacial northward population expansion starting from the Pyrenees and Italy. Apparently, the Pyrenees and the Alps were not barriers to the dispersal of Trichuris populations. PMID:22906769

Callejón, Rocío; De Rojas, Manuel; Feliú, Carlos; Balao, Francisco; Marrugal, Angela; Henttonen, Heikki; Guevara, Diego; Cutillas, Cristina

2012-11-01

278

Holocene Vegetation History from Fossil Rodent Middens near Arequipa, Peru  

NASA Astrophysics Data System (ADS)

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

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

2001-09-01

279

Emmonsiosis of wild rodents and insectivores in Czechland.  

PubMed

Adiaspores of the fungus Emmonsia crescens were detected microscopically in the lung tissue of 13% of 10.081 small mammals belonging to 24 species examined in 14 areas of the Czech Republic between 1986 and 1997; 441/1.934 (23%) Clethrionomys glareolus, 1/6 (17%) Arvicola terrestris, 357/2.172 (16%) Apodemus flavicollis, 220/1.981 (11%). A sylvaticus, 23/265 (9%) A. microps, 11/81 (14%) Microtus subterraneus, 93/1.275 (7%) M. arvalis, 98/1.439 (7%) M. agrestis, 1/3 (33%) Ondatra zibethicus, 1/1 Cricetus cricetus, 1/20 (5%) Crocidura suaveolens, 2/40 (5%) Neomys fodiens, and 13/529 (2%) Sorex araneus were infected. Emmonsiosis was not recorded among the species of rodents that do not build their nests in the soil (Muscardinus avellanarius, Micromys minutus, Mus musculus, Rattus norvegicus). The overall prevalence of emmonsiosis was significantly higher in adult (19%) than in juvenile (7%) mammals, and in rodents (13%, and 20% in adults) than in insectivores (2%, and 4% in adults). The frequency of infected mammals also varied according to geographic area, altitude, habitat, and season. PMID:10231750

Hubálek, Z

1999-04-01

280

Molecular detection of bacterial contamination in gnotobiotic rodent units  

PubMed Central

Gnotobiotic rodents provide an important technique to study the functional roles of commensal bacteria in host physiology and pathophysiology. To ensure sterility, these animals must be screened frequently for contamination. The traditional screening approaches of culturing and Gram staining feces have inherent limitations, as many bacteria are uncultivable and fecal Gram stains are difficult to interpret. Thus, we developed and validated molecular methods to definitively detect and identify contamination in germ-free (GF) and selectively colonized animals. Fresh fecal pellets were collected from rodents housed in GF isolators, spontaneously contaminated ex-GF isolators, selectively colonized isolators and specific pathogen-free (SPF) conditions. DNA isolated from mouse and rat fecal samples was amplified by polymerase chain reaction (PCR) and subjected to quantitative PCR (qPCR) using universal primers that amplify the 16S rRNA gene from all bacterial groups. PCR products were sequenced to identify contaminating bacterial species. Random amplification of polymorphic DNA (RAPD) PCR profiles verified bacterial inoculation of selectively colonized animals. These PCR techniques more accurately detected and identified GF isolator contamination than current standard approaches. These molecular techniques can be utilized to more definitively screen GF and selectively colonized animals for bacterial contamination when Gram stain and/or culture results are un-interpretable or inconsistent. PMID:23887190

Packey, Christopher D; Shanahan, Michael T; Manick, Sayeed; Bower, Maureen A; Ellermann, Melissa; Tonkonogy, Susan L; Carroll, Ian M; Sartor, R Balfour

2013-01-01

281

Digestive strategies in the South American subterranean rodent Ctenomys talarum.  

PubMed

Ctenomys talarum is a subterranean herbivorous rodent which due to its particular life style is frequently exposed to variations in surface environmental conditions (i.e. food quality and availability, temperature). Thus, unlike other subterranean rodents, C. talarum has to buffer both the surface and burrow challenging environmental conditions. We studied the occurrence of digestive strategies at different levels of C. talarum living in their natural habitat. We determined the dimensions of different parts of the gastrointestinal tract and organs along as the activity of key digestive enzymes (disaccharidase, N-aminopeptidase) in different parts of the gut in individuals seasonally caught. The results show that C. talarum exhibits characteristics in the gut at the biochemical level (high disaccharidase activities in small intestine, high N-aminopeptidase activity in the caecum and large intestine, and a seasonal differential modulation of N-aminopeptidase activity in small and large intestines), which could represent adaptive strategies to face seasonal variations in key environmental factors. PMID:18562229

del Valle, Juana C; Mañanes, Alejandra A López

2008-08-01

282

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. PMID:22558427

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

2012-01-01

283

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

284

Chern classes of tropical vector bundles  

NASA Astrophysics Data System (ADS)

We introduce tropical vector bundles, morphisms and rational sections of these bundles and define the pull-back of a tropical vector bundle and of a rational section along a morphism. Most of the definitions presented here for tropical vector bundles will be contained in Torchiani, C., Line Bundles on Tropical Varieties, Diploma thesis, Technische Universität Kaiserslautern, Kaiserslautern, 2010, for the case of line bundles. Afterwards we use the bounded rational sections of a tropical vector bundle to define the Chern classes of this bundle and prove some basic properties of Chern classes. Finally we give a complete classification of all vector bundles on an elliptic curve up to isomorphisms.

Allermann, Lars

2012-10-01

285

Tropical Storm Erin  

NASA Technical Reports Server (NTRS)

Location: The Atlantic Ocean 210 miles south of Galveston, Texas Categorization: Tropical Storm Sustained Winds: 40 mph (60 km/hr)

[figure removed for brevity, see original site] [figure removed for brevity, see original site] Infrared ImageMicrowave Image

Infrared Images Because infrared radiation does not penetrate through clouds, AIRS infrared images show either the temperature of the cloud tops or the surface of the Earth in cloud-free regions. The lowest temperatures (in purple) are associated with high, cold cloud tops that make up the top of the storm. In cloud-free areas the AIRS instrument will receive the infrared radiation from the surface of the Earth, resulting in the warmest temperatures (orange/red).

Microwave Images In the AIRS microwave imagery, deep blue areas in storms show where the most precipitation occurs, or where ice crystals are present in the convective cloud tops. Outside of these storm regions, deep blue areas may also occur over the sea surface due to its low radiation emissivity. On the other hand, land appears much warmer due to its high radiation emissivity.

Microwave radiation from Earth's surface and lower atmosphere penetrates most clouds to a greater or lesser extent depending upon their water vapor, liquid water and ice content. Precipitation, and ice crystals found at the cloud tops where strong convection is taking place, act as barriers to microwave radiation. Because of this barrier effect, the AIRS microwave sensor detects only the radiation arising at or above their location in the atmospheric column. Where these barriers are not present, the microwave sensor detects radiation arising throughout the air column and down to the surface. Liquid surfaces (oceans, lakes and rivers) have 'low emissivity' (the signal isn't as strong) and their radiation brightness temperature is therefore low. Thus the ocean also appears 'low temperature' in the AIRS microwave images and is assigned the color blue. Therefore deep blue areas in storms show where the most precipitation occurs, or where ice crystals are present in the convective cloud tops. Outside of these storm regions, deep blue areas may also occur over the sea surface due to its low radiation emissivity. Land appears much warmer due to its high radiation emissivity.

Visible/Near-Infrared Images The AIRS instrument suite contains a sensor that captures radiation in four bands of the visible/near-infrared portion of the electromagetic spectrum. Data from three of these bands are combined to create 'visible' images similar to a snapshot taken with your camera.

The Atmospheric Infrared Sounder Experiment, with its visible, infrared, and microwave detectors, provides a three-dimensional look at Earth's weather. Working in tandem, the three instruments can make simultaneous observations all the way down to the Earth's surface, even in the presence of heavy clouds. With more than 2,000 channels sensing different regions of the atmosphere, the system creates a global, 3-D map of atmospheric temperature and humidity and provides information on clouds, greenhouse gases, and many other atmospheric phenomena. The AIRS Infrared Sounder Experiment flies onboard NASA's Aqua spacecraft and is managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., under contract to NASA. JPL is a division of the California Institute of Technology in Pasadena.

2007-01-01

286

Black Swan Tropical Cyclones  

NASA Astrophysics Data System (ADS)

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

Emanuel, K.; Lin, N.

2012-12-01

287

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

288

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

EPA Science Inventory

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

289

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

290

Sound Localization in a Predatory Rodent, the Northern Grasshopper Mouse (Onychomys leucogaster )  

Microsoft Academic Search

A comparison of the ability of mammals to localize sound revealed that among the animals examined to date, none of the rodents have been able to localize as accurately as the carnivores. Because all of these rodents are prey animals, the question arises as to whether their poor localization acuity is a phyletic trait of Rodentia or whether it is

Rickye S. Heffner; Henry E. Heffner

1988-01-01

291

HumanWildlife Interactions 5(2):269275, Fall 2011 Rodent population management at Kansas  

E-print Network

rodents (e.g., beavers [Castor canadensis]; porcupines [Erethizon dorsatum]; and woodchucks [Marmota spp management (i.e., use of rodenticides) or by habitat management (i.e., vegetation and land-use management for rodents (e.g., allowing tall grass in an effort to reduce loafing habitat for flocking birds) or reduced

292

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

293

The parasitism of immature stages of Ixodes loricatus (Acari: Ixodidae) on wild rodents in Argentina  

Microsoft Academic Search

Ixodes loricatus has long been considered with strict-total specificity to New World Marsupials. However, frequent findings of its immature stages on rodents suggest that these vertebrates play an important role in the tick’s life cycle. Aspects dealing with the ecology of Sigmodontinae rodents infestation by I. loricatus are unknown. To contribute to the knowledge of the ecology of this tick

Pablo M. Beldomenico; Marcela Lareschi; Santiago Nava; Atilio J. Mangold; Alberto A. Guglielmone

2005-01-01

294

Teasing Apart the Effects of Seed Size and Energy Content on Rodent Scatter-Hoarding Behavior  

PubMed Central

Scatter-hoarding rodents are known to play a crucial role in the seed dispersal of many plant species. Numerous studies have indicated that both seed size and the energy content of seeds can affect rodent foraging behavior. However, seed size is usually associated with energy content per seed, making it difficult to isolate how seed size and energy affect rodent foraging preferences. This study used 99 treatments of artificial seeds (11 seed sizes×9 levels of energy content) to tease apart the effect of seed size and energy content on rodent seed-caching behavior. Both seed traits showed significant effects, but their details depended on the stage of the rodent foraging process. Seeds with higher energy content were harvested more rapidly while seed size only had a modest effect on harvest rate. However, after harvesting, seed size showed a much stronger effect on rodent foraging behavior. Rodents’ choice of which seeds to remove and cache, as well as seed dispersal distance, seemed to reflect an optimal seed size. Our findings could be adapted in future studies to gain a better understanding of scatter-hoarding rodent foraging behavior, and the co-evolutionary dynamics between plant seed production and seed dispersers. PMID:25350369

Wang, Bo; Yang, Xiaolan

2014-01-01

295

SUPRACHIASMATIC NUCLEUS AND INTERGENICULATE LEAFLET IN THE DIURNAL RODENT OCTODON DEGUS  

E-print Network

SUPRACHIASMATIC NUCLEUS AND INTERGENICULATE LEAFLET IN THE DIURNAL RODENT OCTODON DEGUS: RETINAL in the diurnal rodent Octodon degus, a species that manifests robust circadian responses to photic and non tract; (iii) the geniculohypothalamic tract; and (iv) retinogen- iculate projections in O. degus. Using

Lee, Theresa

296

MORPHOLOGICALLY MIXED CHEMICALELECTRICAL SYNAPSES FORMED BY PRIMARY AFFERENTS IN RODENT VESTIBULAR NUCLEI  

E-print Network

MORPHOLOGICALLY MIXED CHEMICAL­ELECTRICAL SYNAPSES FORMED BY PRIMARY AFFERENTS IN RODENT VESTIBULAR/electrical synapses in the lateral vestibular nucleus of rat were described over 40 years ago. Because gap junctions the distribution and cellular localization of electrical synapses in the adult and develop- ing rodent vestibular

Rash, John E.

297

Draft Genome Sequence of the Rodent Opportunistic Pathogen Pasteurella pneumotropica ATCC 35149T  

PubMed Central

Pasteurella pneumotropica is an opportunistic pathogen in rodents that is commonly isolated from upper respiratory tracts in laboratory rodents. Here, we report the draft genome sequence of the P. pneumotropica type strain ATCC 35149, which was first isolated and characterized as biotype Jawetz. PMID:25103762

Ishikawa, Hiroki; Asano, Ryoki; Ueshiba, Hidehiro; Matsumoto, Tetsuya; Boot, Ron

2014-01-01

298

Rapid ventricular repolarization in rodents: Electrocardiographic manifestations, molecular mechanisms, and clinical insights  

Microsoft Academic Search

This article examines specific electrocardiographic (ECG) and electrophysiological features of ventricular repolarization in rats and mice, and the role of depolarization-activated potassium currents in mediating the unique features of ECG recordings in these rodents. This article describes the currents that underlie ventricular repolarization in these rodents, identifies terminology that appropriately describes the unique features of murine ECG recordings, and correlates

Ihor Gussak; Bernard R. Chaitman; Stephen L. Kopecky; Jeanne M. Nerbonne

2000-01-01

299

From Bench to Cageside: Risk Assessment for Rodent Pathogen Contamination of Cells and Biologics  

Microsoft Academic Search

Many newly developed animal models involve the transfer of cells, serum, or other tissue-derived products into live rodents. These biologics can serve as repositories for ad- ventitious rodent pathogens that, when used in animal stud- ies, can alter research outcomes and result in endemic outbreaks. This review includes a description of some of the biologics that have inadvertently introduced infectious

Norman C. Peterson

300

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

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

301

Programmed versus stimulus-driven antiparasitic grooming in a desert rodent  

Microsoft Academic Search

We tested 2 hypotheses concerning regulation of grooming in flea-infested rodents and examined if 2 grooming components, scan and scratch grooming, are controlled by programmed and stimulus-driven regulation, respectively. The programmed grooming hypothesis proposes central programming that periodically evokes a bout of grooming to remove ectoparasites before they are attached and predicts that juvenile rodents 1) regardless of infestation status

Hadas Hawlena; Dikla Bashary; Zvika Abramsky; Irina S. Khokhlova; Boris R. Krasnov

2008-01-01

302

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

303

Competitive release in microhabitat use among coexisting desert rodents: a natural experiment  

Microsoft Academic Search

Competitive release among desert rodents on sand dunes of differing species richness was examined in the Great Basin and Mohave Deserts, USA. Expansions in microhabitat use were exhibited by the kangaroo rats Dipodomys ordii and D. merriami (granivorous heteromyid rodents, weighing 49 and 42 g, respectively) as the number of coexisting heteromyid species decreased geographically. Perognathus longimembris, the only common

Eric Larsen

1986-01-01

304

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...

305

Diffusion and home range parameters for rodents: Peromyscus maniculatus in New Mexico  

E-print Network

Diffusion and home range parameters for rodents: Peromyscus maniculatus in New Mexico G. Abramson a in the field. A basic assumption of that model is that the rodent movement may be regarded as diffusive and characterized by a parameter D, the diffusion coefficient. Various contributions to the understanding of animal

306

Pika and vole mitochondrial genomes increase support for both rodent monophyly and glires  

Microsoft Academic Search

Complete mitochondrial genomes are reported for a pika (Ochotona collaris) and a vole (Volemys kikuchii) then analysed together with 35 other mitochondrial genomes from mammals. With standard phylogenetic methods the pika joins with the other lagomorph (rabbit) and the vole with the other murid rodents (rat and mouse). In addition, with hedgehog excluded, the seven rodent genomes consistently form a

Yu-Hsin Lin; Peter J. Waddell; David Penny

2002-01-01

307

Catalepsy as a rodent model for detecting antipsychotic drugs with extrapyramidal side effect liability  

Microsoft Academic Search

The predictive validity of catalepsy as a rodent model for detecting the extrapyramidal side effects (EPS) of antipsychotic drugs was recently questioned when the novel antipsychotic savoxepine produced little catalepsy in rodents while producing significant EPS in schizophrenic patients. Because catalepsy is viewed as an important model for predicting EPS, we decided to re-evaluate the effects of savoxepine. Savoxepine, clozapine,

D. C. Hoffman; H. Donovan

1995-01-01

308

75Vol. 5, No. 1, JanuaryFebruary 1999 Emerging Infectious Diseases Hantaviruses, rodent-borne RNA viruses,  

E-print Network

reservoir is the deer mouse (Peromyscus maniculatus). Hantavirus- infected rodents were identified those associated with Peromyscus species rodents), although the nucleotide sequences of many hantaviruses from Genetic Diversity and Distribution of Peromyscus-Borne Hantaviruses in North America Martha C

309

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. PMID:22469569

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

2012-01-01

310

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

PubMed Central

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

2013-01-01

311

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. PMID:20158331

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

2010-01-01

312

Next-Generation Sequencing for Rodent Barcoding: Species Identification from Fresh, Degraded and Environmental Samples  

PubMed Central

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; Pages, Marie; Cosson, Jean-Francois

2012-01-01

313

Effects of Fat and Protein Levels on Foraging Preferences of Tannin in Scatter-Hoarding Rodents  

PubMed Central

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

2012-01-01

314

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. PMID:8013399

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

1993-01-01

315

Differences in hoarding behaviors among six sympatric rodent species on seeds of oil tea ( Camellia oleifera) in Southwest China  

Microsoft Academic Search

Seed hoarding is an important behavioral adaptation to food shortages for many rodent species. Sympatric rodents may affect the natural regeneration of large-seeded trees differently as seed dispersers or seed predators. Using seeds of oil tea (Camellia oleifera), we investigated differences in hoarding behaviors among six sympatric rodent species in semi-natural enclosures in a subtropical forest in southwest of China.

Gang Chang; Zhibin Zhang

2011-01-01

316

Rodent treadmill for inhalation toxicological studies and respirometry  

SciTech Connect

A 10-runway treadmill was enclosed for inhalation toxicological studies of rodents under exercise exposure to environmental pollutants. The exposure system was lined with sheet stainless steel to minimize scrubbing of charged particles and reactive gases. Average metabolic gas exchange of exercising animals was derived from measurements of inlet or outlet airflow and data from an O/sub 2/ analyzer in conjunction with either a CO/sub 2/ or N/sub 2/ analyzer. An airflow rate of 400 l x min-1 ensured a response time of 1 min to reach 95% of a step change in metabolic rate and held scrubbing losses of an O/sub 3/ test atmosphere to less than 2% of treadmill inlet concentration. Gas exchange averaged for 10 rats during incremental exercise up to their highest collective performance was similar to published data for rats tested individually.

Mautz, W.J.; Phalen, R.F.; McClure, T.R.; Bufalino, C.

1985-02-01

317

[Structural characteristics of certain Rodents spines (Rodentia: Myomorpha, Hystricomorpha)].  

PubMed

The architectonics of spines and hair was studied in Neacomys spinosus, Arvicanthis somalicus, Leopoldamys sabanus, L. edwardsi, Maxomys moi, M. surifer, Niviventer fulvescens, N. confucianus, N. cremoriventer, Acomys cahirinus, A. somalica, Hystrix indica, H. cristata, Atherurus macrourus, Erethizon dorsatum, Proechimys steerei, and Lonchotrix emiliae. The presence of a dorsal longitudinal furrow covered by a modified cuticle is a common structural feature of spines in all studied species except E. dorsatum, H. indica, and the frontal surface of the mosaic (scales located side by side) and terrace cuticle (steps between scales) varies in different species from smooth to rib-folded. A terminology has been proposed to describe the main structures of spine and hair. The adaptive significance of the spine architectonics in rodents is discussed. PMID:11525125

Chernova, O F; Kuznetsov, G V

2001-01-01

318

Hippocampal lipoprotein lipase regulates energy balance in rodents.  

PubMed

Brain lipid sensing is necessary to regulate energy balance. Lipoprotein lipase (LPL) may play a role in this process. We tested if hippocampal LPL regulated energy homeostasis in rodents by specifically attenuating LPL activity in the hippocampus of rats and mice, either by infusing a pharmacological inhibitor (tyloxapol), or using a genetic approach (adeno-associated virus expressing Cre-GFP injected into Lpl (lox/lox) mice). Decreased LPL activity by either method led to increased body weight gain due to decreased locomotor activity and energy expenditure, concomitant with increased parasympathetic tone (unchanged food intake). Decreased LPL activity in both models was associated with increased de novo ceramide synthesis and neurogenesis in the hippocampus, while intrahippocampal infusion of de novo ceramide synthesis inhibitor myriocin completely prevented body weight gain. We conclude that hippocampal lipid sensing might represent a core mechanism for energy homeostasis regulation through de novo ceramide synthesis. PMID:24634821

Picard, Alexandre; Rouch, Claude; Kassis, Nadim; Moullé, Valentine S; Croizier, Sophie; Denis, Raphaël G; Castel, Julien; Coant, Nicolas; Davis, Kathryn; Clegg, Deborah J; Benoit, Stephen C; Prévot, Vincent; Bouret, Sébastien; Luquet, Serge; Le Stunff, Hervé; Cruciani-Guglielmacci, Céline; Magnan, Christophe

2014-04-01

319

Seroepidemiologic studies of hantavirus infection among wild rodents in California.  

PubMed Central

A total of 4,626 mammals were serologically tested for antibodies to Sin Nombre virus. All nonrodent species were antibody negative. Among wild rodents, antibody prevalence was 8.5% in murids, 1.4% in heteromyids, and < 0.1% in sciurids. Of 1,921 Peromyscus maniculatus (deer mice), 226 (11.8%) were antibody positive, including one collected in 1975. The highest antibody prevalence (71.4% of 35) was found among P. maniculatus on Santa Cruz Island, off the southern California coast. Prevalence of antibodies among deer mice trapped near sites of human cases (26.8% of 164) was significantly higher than that of mice from other sites (odds ratio = 4.5; 95% confidence interval = 1.7, 11.6). Antibody prevalence increased with rising elevation (> 1,200 meters) and correlated with a spatial cluster of hantavirus pulmonary syndrome cases in the Sierra Nevada. PMID:9204301

Jay, M.; Ascher, M. S.; Chomel, B. B.; Madon, M.; Sesline, D.; Enge, B. A.; Hjelle, B.; Ksiazek, T. G.; Rollin, P. E.; Kass, P. H.; Reilly, K.

1997-01-01

320

Identification of novel anelloviruses with broad diversity in UK rodents.  

PubMed

Anelloviruses are a family of small circular ssDNA viruses with a vast genetic diversity. Human infections with the prototype anellovirus, torque teno virus (TTV), are ubiquitous and related viruses have been described in a number of other mammalian hosts. Despite over 15 years of investigation, there is still little known about the pathogenesis and possible disease associations of anellovirus infections, arising in part due to the lack of a robust cell culture system for viral replication or tractable small-animal model. We report the identification of diverse anelloviruses in several species of wild rodents. The viruses are highly prevalent in wood mice (Apodemus sylvaticus) and field voles (Microtus agrestis), detectable at a low frequency in bank voles (Myodes glareolus), but absent from house mice (Mus musculus). The viruses identified have a genomic organization consistent with other anelloviruses, but form two clear phylogenetic groups that are as distinct from each other as from defined genera. PMID:24744300

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

2014-07-01

321

Photoperiodic control of circadian activity rhythms in diurnal rodents  

NASA Astrophysics Data System (ADS)

The responses of red squirrels (Tamiasciurus hudsonicus) and eastern chipmunks (Tamias striatus) to complete and skeleton light-dark (LD) cycles were compared. The skeletons, comprised of two 1-h pulses of light per day, effectively simulated the complete photoperiods in the squirrels, but not the chipmunks. Skeleton photoperiods greater than 12-h caused the chipmunks to shift activity from the longer to the shorter of the two intervals between the pulses. To interpret the mechanism of phase control, squirrels and chipmunks were kept in continuous darkness and exposed to 1-h light pulses every 10 days. The time-course of entrainment was also quantified. Both techniques produced light-response curves. The data suggest that the parametric and non-parametric contributions to entrainment are different in these two rodent species.

Kramm, K. R.; Kramm, Deborah A.

1980-03-01

322

Ljungan virus is endemic in rodents in the UK.  

PubMed

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

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

2014-03-01

323

Wheel-running behavior in 12 species of muroid rodents.  

PubMed

The objective of this research was to describe the levels and periodicity of wheel running in 12 species of muroid rodents in order that comparisons could be made among different measures of activity in a variety of species. Six males from each species (Peromyscus polionotus, P. eremicus, P. leucopus, P. maniculatus, P. gossypinus, Microtus pennysylvanicus, M. montanus, M. canicaudus, M. ochrogaster, Calomys callos us, Onychomys leucogaster, and Mus musculus) were tested in running wheels for 14 days, with the amount of running recorded hourly. There were significant species differences in amount of wheel running, with Peromyscus generally running more than Microtus. All species displayed marked nocturnality. Thus, Peromyscus display consistent nocturnality both across species, and for various behavioral patterns measured using a variety of methods. By contrast, Microtus display a nocturnal pattern of wheel running, but not of eating, drinking, and various other behavioral patterns. These differences appear to reflect adaptations related to habit and diet. PMID:24925276

Dewsbury, D A

1980-09-01

324

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. PMID:21553232

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

2011-01-01

325

Nutritional disorders in tropical neurology.  

PubMed

About three-fourths of the total world population live in the tropics but consume only 6% of worldwide food production and contribute 15% of the world's net revenue explaining the short life expectancy, high infantile mortality, and poor daily caloric intake; moreover, lack of clean drinking water and deficient sanitation promote water-borne infections, diarrhea, and risk of malabsorption that contribute to the prevalence of malnutrition in the tropics. One-third of the world's population consumes insufficient iodine increasing the risk for mental retardation and deafness due to maternal hypothyroidism. The main nutritional syndromes comprise protein-energy malnutrition (marasmus and kwashiorkor); nutritional neuropathies, myelopathies and neuromyelopathies, as well as specific deficiencies of vitamins and micronutrients including iodine, iron, zinc, and selenium. PMID:23829926

Román, Gustavo C

2013-01-01

326

Fluid Mechanics of Tropical Cyclones  

NASA Astrophysics Data System (ADS)

Typhoons in the northwest Pacific and hurricanes in the northeast Atlantic are particular instances of a global phenomenon with frequently disastrous consequences known as the Tropical Cyclone (TC). This is an intense cyclone, generated over a tropical ocean with kinetic energy 1018 J or more, which extends over several hundred kilometres and yet is above all characterized by its calm central region: ``the eye of the storm''. In a TC (not, of course, to be confused with such completely different phenomena as tornadoes) both the energy input and its dissipation mainly occur within that boundary layer between air and ocean which, at high TC wind speeds of 50-60 m/s, comprises essentially ``a third fluid'': ocean spray. Afterwards, as a TC reaches land, disastrous effects of several different kinds may occur, and this paper outlines how fluid mechanics contributes towards worldwide struggles to reduce the human impact of TC disasters.

Lighthill, James, Sir

327

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.

328

Tropical Mesoscale and Local Circulations  

NSDL National Science Digital Library

This interactive module is part of an online university-level tropical synoptic meteorology course, which helps international meteorologists meet basic instructional requirements. In the module, we discuss: Mesoscale, thermally-forced circulations (i.e. land-sea breeze and mountain-valley breeze), including How they are formed and their diurnal cycle Factors that modify thermally forced circulations The weather associated with thermally forced circulations, particularly convection and other significant weather Interactions of mesoscale, thermally forced circulations with other atmospheric phenomena, including Intersection of mesoscale circulations and of mesoscale circulations with convective outflow boundaries Thermally forced circulation interactions with monsoonal and trade wind flows The impact of thermally forced and interacting circulations at various scales on the diurnal cycle of precipitation in the tropics, and A case example from the Lake Victoria basin, showing complex thermally forced circulations, outflow boundaries, and synoptic scale flow.

Comet

2012-11-27

329

Polytropic process and tropical Cyclones  

E-print Network

We show a parallelism between the expansion and compression of the atmosphere in the secondary cycle of a tropical cyclone with the fast expansion and compression of wet air in a bottle. We present a simple model in order to understand how the system (cyclone) draws energy from the air humidity. In particular we suggest that the upward (downward) expansion (compression) of the warm (cold) moist (dry) air follows a polytropic process, $PV^\\beta$= constant. We show both experimentally and analytically that $\\beta$ depends on the initial vapor pressure in the air. We propose that the adiabatic stages in the Carnot-cycle model for the tropical cyclone be replaced by two polytropic stages. These polytropic processes can explain how the wind wins energy and how the rain and the dry bands are produced inside the storm.

Romanelli, Alejandro; Rodríguez, Juan

2013-01-01

330

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. PMID:23826371

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

2013-01-01

331

Modelling cognitive affective biases in major depressive disorder using rodents  

PubMed Central

Major depressive disorder (MDD) affects more than 10% of the population, although our understanding of the underlying aetiology of the disease and how antidepressant drugs act to remediate symptoms is limited. Major obstacles include the lack of availability of good animal models that replicate aspects of the phenotype and tests to assay depression-like behaviour in non-human species. To date, research in rodents has been dominated by two types of assays designed to test for depression-like behaviour: behavioural despair tests, such as the forced swim test, and measures of anhedonia, such as the sucrose preference test. These tests have shown relatively good predictive validity in terms of antidepressant efficacy, but have limited translational validity. Recent developments in clinical research have revealed that cognitive affective biases (CABs) are a key feature of MDD. Through the development of neuropsychological tests to provide objective measures of CAB in humans, we have the opportunity to use ‘reverse translation’ to develop and evaluate whether similar methods are suitable for research into MDD using animals. The first example of this approach was reported in 2004 where rodents in a putative negative affective state were shown to exhibit pessimistic choices in a judgement bias task. Subsequent work in both judgement bias tests and a novel affective bias task suggest that these types of assay may provide translational methods for studying MDD using animals. This review considers recent work in this area and the pharmacological and translational validity of these new animal models of CABs. Linked Articles This article is part of a themed section on Animal Models in Psychiatry Research. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2014.171.issue-20 PMID:24467454

Hales, Claire A; Stuart, Sarah A; Anderson, Michael H; Robinson, Emma S J

2014-01-01

332

Adaptive Evolution in Rodent Seminal Vesicle Secretion Proteins  

PubMed Central

Proteins involved in reproductive fitness have evolved unusually rapidly across diverse groups of organisms. These reproductive proteins show unusually high rates of amino acid substitutions, suggesting that the proteins have been subject to positive selection. We sought to identify seminal fluid proteins experiencing adaptive evolution because such proteins are often involved in sperm competition, host immunity to pathogens, and manipulation of female reproductive physiology and behavior. We performed an evolutionary screen of the mouse prostate transcriptome for genes with elevated evolutionary rates between mouse and rat. We observed that secreted rodent prostate proteins evolve approximately twice as fast as nonsecreted proteins, remarkably similar to findings in the primate prostate and in the Drosophila male accessory gland. Our screen led us to identify and characterize a group of seminal vesicle secretion (Svs) proteins and to show that the gene Svs7 is evolving very rapidly, with many amino acid sites under positive selection. Another gene in this group, Svs5, showed evidence of branch-specific selection in the rat. We also found that Svs7 is under selection in primates and, by using three-dimensional models, demonstrated that the same regions have been under selection in both groups. Svs7 has been identified as mouse caltrin, a protein involved in sperm capacitation, the process responsible for the timing of changes in sperm activity and behavior, following ejaculation. We propose that the most likely explanation of the adaptive evolution of Svs7 that we have observed in rodents and primates stems from an important function in sperm competition. PMID:18718917

Clark, Nathaniel L.; Nguyen, Eric D.; Swanson, Willie J.

2008-01-01

333

Dietary cholesterol enhances torpor in a rodent hibernator.  

PubMed

Dietary cholesterol can affect both body lipid composition and steroid hormone concentration. We investigated whether a diet rich in cholesterol influences torpor patterns of hibernating chipmunks (Tamias amoenus) and, if so, whether these changes are better explained by diet-induced changes in body lipid composition or the concentration of testosterone, which at high levels inhibits torpor. Two groups of chipmunks were maintained either on a cholesterol diet (rodent chow containing 10% cholesterol) or a control diet (rodent chow) during pre-hibernation fattening and throughout the hibernation season. Torpid chipmunks on the cholesterol diet had significantly lower minimum body temperatures (-0.2 +/- 0.2 vs -0.6 +/- 0.2 degree C), lower metabolic rates (0.029 +/- 0.002 ml O2 g-1 h-1 vs 0.035 +/- 0.001 ml O2 g-1 h-1), and longer torpor bouts at -1 degree C (6.8 +/- 0.5 vs 4.1 +/- 1.0 days) than chipmunks on the control diet. Dietary cholesterol resulted in a significant increase in blood plasma cholesterol (sevenfold), liver cholesterol content (6.9-fold) and liver triglyceride content (3.5-fold) in comparison to controls. In contrast, dietary cholesterol had no detectable effect on the concentration of plasma testosterone, which was very low in both groups. Since torpor was deeper and longer in animals on the cholesterol diet our study suggests that torpor patterns of chipmunks were either directly affected by the dietary cholesterol or via changes in body lipid composition. PMID:9286090

Geiser, F; Kenagy, G J; Wingfield, J C

1997-08-01

334

Pulmonary Toxicity Studies of Lunar Dusts in Rodents  

NASA Technical Reports Server (NTRS)

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

Lam, Chiu-wing; James, John T.

2009-01-01

335

DNA Barcoding of Sigmodontine Rodents: Identifying Wildlife Reservoirs of Zoonoses  

PubMed Central

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

Muller, Livia; Goncalves, Gislene L.; Cordeiro-Estrela, Pedro; Marinho, Jorge R.; Althoff, Sergio L.; Testoni, Andre. F.; Gonzalez, Enrique M.; Freitas, Thales R. O.

2013-01-01

336

Tropical Ecosystem and Soil Development  

E-print Network

nutrient content and ecosystem development #12;How is soil generated from rocks? Weathering #12;SoilTropical Ecosystem and Soil Development Joost van Haren Ecology 596L 09/03/10 #12;Ecosystem biomass strongly dependent on soil Manaus, BDFF plots #12;0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 O ld oxisols

Saleska, Scott

337

Viral exanthems in the tropics.  

PubMed

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

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

2007-01-01

338

Ecotoxicology of tropical marine ecosystems  

SciTech Connect

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 on impacts of chemical stressors on mangrove forests, seagrass meadows, and coral reefs are discussed in the context of ecosystem management and ecological risk assessment. Three classes of pollutants have received attention: heavy metals, petroleum, and synthetic organics. Heavy metals have been detected in all three ecosystems, causing physiological stress, reduced reproductive success, and outright mortality in associated invertebrates and fishes. Oil spills have been responsible for the destruction of entire coastal shallow-water communities, with recovery requiring years. Herbicides are particularly detrimental to mangroves and seagrasses and adversely affect the animal-algal symbioses in corals. Pesticides interfere with chemical cues responsible for key biological processes, including reproduction and recruitment of a variety of organisms. Information is lacking with regard to long-term recovery, indicator species, and biomarkers for tropical communities. Critical areas that are beginning to be addressed include the development of appropriate benchmarks for risk assessment, baseline monitoring criteria, and effective management strategies to protect tropical marine ecosystems in the face of mounting anthropogenic disturbance.

Peters, E.C. [Tetra Tech, Inc., Fairfax, VA (United States); Gassman, N.J.; Firman, J.C. [Univ. of Miami, FL (United States). Rosenstiel School of Marine and Atmospheric Science; Richmond, R.H. [Univ. of Guam, Mangilao (Guam). Marine Lab.; Power, E.A. [EVS Environment Consultants, Ltd., North Vancouver, British Columbia (Canada)

1997-01-01

339

Spatial Coherence of Tropical Rainfall  

NASA Astrophysics Data System (ADS)

We characterise the spatial coherence of tropical rain and its wet spells from observations (TRMM) and assess if models (CMIP5) are able to reproduce the observed features. Based on 15 years (1998-2012) of TRMM 3B42 (V7) 1-degree, daily rainfall, we estimate the spatial decorrelation scale (e-folding distance) of rain at each location in the tropics. A ratio of zonal to meridional spatial scales clearly illustrates that while rain patterns tend to be anisotropic (ratio of 4) over tropical ocean regions (particularly over Pacific ITCZ); over land regions, rain tends to be mostly isotropic. This contrast between ocean and land appears to be reasonably well captured by CMIP5 models, although the anisotropy (ratio) over ocean is much higher than in observations. A very curious behaviour in observations is the presence of a coherent band of spatial decorrelation lengths straddling the equator, in the East Pacific, reminiscent of a double ITCZ that some models tend to simulate. A similar analysis of wet spells of different durations suggests that the decorrelation scale is largely independent of the duration of wet spell.

Ratan, Ram; Venugopal, V.; Sukhatme, Jai; Murtugudde, Raghu

2014-05-01

340

Sound localization in a predatory rodent, the northern grasshopper mouse (Onychomys leucogaster).  

PubMed

A comparison of the ability of mammals to localize sound revealed that among the animals examined to date, none of the rodents have been able to localize as accurately as the carnivores. Because all of these rodents are prey animals, the question arises as to whether their poor localization acuity is a phyletic trait of Rodentia or whether it is a trait common to prey species that may be under less selective pressure than predators to localize sound accurately. To answer this question, sound localization acuity was determined in a species that is both predatory and a rodent, the northern grasshopper mouse. Localization thresholds for a single 100-ms noise burst were determined for three grasshopper mice using a conditioned avoidance procedure. Their 50% discrimination threshold of 19 degrees is larger than that of any of the previously tested carnivores and well within the range of other rodents. However, calculations of the binaural sound localization cues available to rodents (based on their head size) suggest that the grasshopper mouse may make more efficient use of the available locus cues than other rodents. Thus, although the grasshopper mouse cannot localize as accurately as carnivores, it appears to be more accurate than predicted for a nonpredatory rodent of its size. PMID:3365945

Heffner, R S; Heffner, H E

1988-03-01

341

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

2011-11-21

342

Ecologically based management of rodents in the real world: applied to a mixed agroecosystem in Vietnam.  

PubMed

Rodents cause significant damage to lowland irrigated rice crops in the Red River Delta of Vietnam. A four-year study was conducted in 1999-2002 to examine the effectiveness of applying rodent control practices using the principles of ecologically based pest management. Four 100-150 ha study sites adjacent to villages were selected and farmers on two treated sites were asked to follow a set of rodent management practices, while farmers on the untreated sites were asked not to change their typical practices. Farmers on the treated sites were encouraged to use trap-barrier systems (TBS's; 0.065-ha early planted crop surrounded by a plastic fence with multiple capture traps; one TBS for every 10-15 ha), to work together over large areas by destroying burrows in refuge habitats soon after planting (before the rats reestablish in the fields and before the onset of breeding), synchronizing planting and harvesting of the their rice crops, cleaning up weeds and piles of straw, and keeping bund (embankment) size small (<30 cm) to prevent burrowing. A 75% reduction in the use of rodenticides and plastic barrier fences (without traps or an early crop) was achieved on treated sites. The abundance of rodents was low after implementation of the management practices across all sites. There was no evidence for an effect of treatment on the abundance of rodents captured each month using live-capture traps, and no difference in damage between treatments or in yields obtained from the rice crops. Therefore, ecologically based rodent management was equally effective as typical practices for rodent management. Farmers on the treated sites spent considerably less money applying rodent control practices, which was reflected in the comparative increase in the partial benefit:cost of applying ecologically based rodent management from 3:1 on treated sites and untreated sites prior to the implementation of treatments to 17:1 on treated sites in the final year of the project. PMID:17069390

Brown, Peter R; Tuan, Nguyen Phu; Singleton, Grant R; Ha, Phi Thi Thu; Hoa, Phung Thi; Hue, Dao Thi; Tan, Tran Quang; Van Tuat, Nguyen; Jacob, Jens; Müller, Warren J

2006-10-01

343

Camera Trapping: A Contemporary Approach to Monitoring Invasive Rodents in High Conservation Priority Ecosystems  

PubMed Central

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

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

2014-01-01

344

Reconstruction of equilibrium-line altitudes for tropical and sub-tropical glaciers  

Microsoft Academic Search

Past fluctuations of tropical and sub-tropical glaciers provide important palaeoclimate proxies for regions where other forms of evidence are rare. However, published equilibrium-line altitude (ELA) estimates for tropical and sub-tropical glaciers at the LGM vary widely, reflecting the diversity of methods and approaches employed by different research groups. This complicates regional and global comparisons of ELA estimates, and emphasises the

Douglas I. Benna; Lewis A. Owenb; Henry A. Osmastonc; Geoffrey O. Seltzer; Stephen C. Porterd; Bryan Marke

345

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

346

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

PubMed Central

GBM (glioblastoma multiforme) is a highly aggressive brain tumour with very poor prognosis despite multi-modalities of treatment. Furthermore, recent failure of targeted therapy for these tumours highlights the need of appropriate rodent models for preclinical studies. In this review, we highlight the most commonly used rodent models (U251, U86, GL261, C6, 9L and CNS-1) with a focus on the pathological and genetic similarities to the human disease. We end with a comprehensive review of the CNS-1 rodent model. PMID:21740400

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

2011-01-01

347

Technologies to sustain tropical forest resources  

SciTech Connect

This report describes the background of tropical forest resource changes, including who is affected, the current status, the visible agents and underlying causes of change, and the organizations involved. Various technologies for resource-sustaining development of tropical forests are discussed. Some are techniques to manage the forests and some are technologies to use forests to protect related resources such as agriculture and water. Issues and options for Congress to promote development and use of technologies that can sustain tropical forest resources globally and within US tropical territories are described. (ACR)

Not Available

1984-03-01

348

The ecology of tropical lakes and rivers  

SciTech Connect

This is self-contained text reviewing tropical limnology. It discusses a number of communities in detail, including plankton, benthic regions, and the water margins. It introduces the characteristic types and assemblies of animals and plants from tropical communities. The measurement and relative magnitude of such quantifiable aspects as abundance, biomass, primary production, secondary production, and decomposition are all outlined, drawing together the diverse threads of freshwater ecology over one of the earth's climatic belts. Deals with use and abuse of water in the tropics and looks at problems of diversity and diversification in tropical waters.

Payne, A.I.

1986-01-01

349

Influence of Tropical Tropopause Layer Cooling on Atlantic Hurricane Activity  

E-print Network

Virtually all metrics of Atlantic tropical cyclone activity show substantial increases over the past two decades. It is argued here that cooling near the tropical tropopause and the associated decrease in tropical cyclone ...

Solomon, Susan

350

Seasonally dry tropical forest mammals: Adaptations and seasonal patterns  

E-print Network

Seasonally dry tropical forests have one of the most extreme climates within tropical ecosystems. Mammals that inhabit tropical dry forests must be capable of dealing with high temperatures, low precipitation in the dry ...

Stoner, Kathryn E.; Timm, Robert M.

2011-01-01

351

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

PubMed Central

Toxoplasma gondii is obligate coccidian zoonotic parasite. Felidae family is definitive and wide ranges of warm-blooded vertebrates are intermediate hosts for the parasite. Rodents are measured as an important source of T. gondii infection for the definitive host. Thus, this study aimed to investigate Toxoplasm infection in rodents of Ahvaz district, southwest of Iran. A total of 100 rodents (73 Rattus norvegicus, 21 Rattus rattus, and 6 Mus musculus) were collected and studied by GRA6PCR and mouse bioassay. The finding indicated that 6 out of 100 (6%) and 2 out of 100 (2%) samples were positive by PCR and mouse bioassay, respectively. The results show notable chronic infection in the rodent and potential transmission of the infection among animal and men in the region. Accordingly, this study recommended investigating of the T. gondii infection in definitive and other intermediate hosts in other points of Khuzestan province, Southwest, Iran. PMID:24605327

Saki, J.; Khademvatan, S.

2014-01-01

352

Insights into relationships among rodent lineages based on mitochondrial genome sequence data  

E-print Network

suborders, with relationships among families or superfamilies remaining problematic. The mtDNA sequences for four new rodent taxa (Aplodontia, Cratogeomys, Erethizon, and Hystrix), along with previously published Euarchontoglires taxa, were analyzed under...

Frabotta, Laurence John

2006-04-12

353

Hantavirus and Arenavirus Antibodies in Persons with Occupational Rodent Exposure, North America  

PubMed Central

Rodents are the principal hosts of Sin Nombre virus, 4 other hantaviruses known to cause hantavirus pulmonary syndrome in North America, and the 3 North American arenaviruses. Serum samples from 757 persons who had worked with rodents in North America and handled neotomine or sigmodontine rodents were tested for antibodies against Sin Nombre virus, Whitewater Arroyo virus, Guanarito virus, and lymphocytic choriomeningitis virus. Antibodies against Sin Nombre virus were found in 4 persons, against Whitewater Arroyo virus or Guanarito virus in 2 persons, and against lymphocytic choriomeningitis virus in none. These results suggest that risk for infection with hantaviruses or arenaviruses usually is low in persons whose occupations entail close physical contact with neotomine or sigmodontine rodents in North America. PMID:17553266

Milazzo, Mary Louise; Armstrong, Lori R.; Childs, James E.; Rollin, Pierre E.; Khabbaz, Rima; Peters, C.J.; Ksiazek, Thomas G.

2007-01-01

354

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

PubMed Central

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

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

2014-01-01

355

Microvascular oxygen tension and flow measurements in rodent cerebral cortex during  

E-print Network

Microvascular oxygen tension and flow measurements in rodent cerebral cortex during baseline, Massachusetts, USA Measuring cerebral oxygen delivery and metabolism microscopically is important measurements of cerebral blood flow (CBF) and oxygen partial pressure (pO2) in cortical microvessels

Srinivasan, Vivek J.

356

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

EPA Science Inventory

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

357

RODENTS: PICTORIAL KEY TO SOME COMMON UNITED STATES GENERA Harold Georee Scott and Margery R. Borom  

E-print Network

HOUSE MOUSE Mus musculus #12;DOMESTIC RODENTS AND COCKROACHES: PICTORIAL KEY TO DROPPINGS Harold Georle.t with ridges ovoid, pointed with ridllU without rid,es length about 1/4-inch Mus musculus HOUSE MOUSE lenll

358

Ardiles et al. Memory loss in a rodent natural model of AD Biological Sciences, Neuroscience  

E-print Network

that starting between 12 and 36 mo of age, the rodent Octodon degus naturally develops neuropathological signs recognition memory, postsynaptic function, and synaptic plasticity. These findings validate Octodon degus

Paris-Sud XI, Université de

359

Electromechanical design of a body weight support system for a therapeutic robot for rodent studies  

E-print Network

As part of an ongoing effort to better understand and treat locomotor disorders, an over-ground therapeutic robot prototype to study recovery of locomotion after spinal cord injury in rodents is under development. One key ...

Mayalu, Michaëlle Ntala

2010-01-01

360

Statistical sensitivity for detection of spatial and temporal patterns in rodent population densities.  

PubMed Central

A long-term monitoring program begun 1 year after the epidemic of hantavirus pulmonary syndrome in the U.S. Southwest tracked rodent density changes through time and among sites and related these changes to hantavirus infection rates in various small-mammal reservoir species and human disease outbreaks. We assessed the statistical sensitivity of the program's field design and tested for potential biases in population estimates due to unintended deaths of rodents. Analyzing data from two sites in New Mexico from 1994 to 1998, we found that for many species of Peromyscus, Reithrodontomys, Neotoma, Dipodomys, and Perognathus, the monitoring program detected species-specific spatial and temporal differences in rodent densities; trap-related deaths did not significantly affect long-term population estimates. The program also detected a short-term increase in rodent densities in the winter of 1997-98, demonstrating its usefulness in identifying conditions conducive to increased risk for human disease. PMID:10081679

Parmenter, C. A.; Yates, T. L.; Parmenter, R. R.; Dunnum, J. L.

1999-01-01

361

BENEFITS OF SMALL-SIZED CACHES FOR SCATTER-HOARDING RODENTS: INFLUENCE OF CACHE SIZE, DEPTH,  

E-print Network

examined the ability of Ord's kangaroo rat (Dipodomys ordii) to exploit artificial caches of different, Dipodomys ordii, plant­animal interactions, scatter hoarding Granivorous rodents are important predators

362

Segment Specification for the Payload Segment of the Reusable Reentry Satellite: Rodent Module Version  

NASA Technical Reports Server (NTRS)

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

1991-01-01

363

Characterizing the dynamic frequency structure of fast oscillations in the rodent hippocampus  

E-print Network

Fast oscillations or “ripples” are found in the local field potential (LFP) of the rodent hippocampus during awake and sleep states. Ripples have been found to correlate with memory related neural processing, however, the ...

Nguyen, David P.

364

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

365

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

PubMed

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. The present study was undertaken to describe limb/paw movements in a variety of common rodents. The movements used for handling sunflower seeds and other foods were videorecorded and analyzed in the guinea pig (Cavia porcellus), Mongolian gerbil (Meriones unguiculatus), Syrian hamster (Mesocricetus auratus), laboratory mouse (Mus musculus), laboratory rat (Rattus norvegicus), gray squirrel (Sciurus carolinensis), red squirrel (Tamiasciurus hudsonicus), Richardson's ground squirrel (Spermophilus richardsonni), prairie dog (Cynomus parvidens), and Canadian beaver (Castor americanus). The results suggested five order-common movements of food handling: (1) locating food by sniffing, (2) grasping food by mouth, (3) sitting back on the haunches to eat, (4) grasping the food using an elbow-in movement, and (5) manipulate the food with the digits. Different species displayed species-typical specializations including (1) bilateral grasping with the paws (gerbil), (2) unilateral grasping with a paw (beaver), (3) unilateral holding (ground squirrels), (4) various grip and digit postures (all species), (5) unilateral object removal from the mouth (gerbil), (6) bilateral thumb holding (squirrels), and (7) simultaneous holding/manipulation of two objects (squirrels). Only the guinea pig did not handle food with its paws, suggesting its behavior is regressive. The existence of a core pattern of paw and digit use in rodents suggests that skilled limb and paw movements originate at least with the common ancestors of the rodent, and likely the common ancestor to rodent and primate lineages, while species-typical movements suggest specialization/regression of limb use has occurred in a number of mammalian orders. PMID:9821545

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

1998-11-01

366

Tropical geometry of statistical models  

PubMed Central

This article presents a unified mathematical framework for inference in graphical models, building on the observation that graphical models are algebraic varieties. From this geometric viewpoint, observations generated from a model are coordinates of a point in the variety, and the sum-product algorithm is an efficient tool for evaluating specific coordinates. Here, we address the question of how the solutions to various inference problems depend on the model parameters. The proposed answer is expressed in terms of tropical algebraic geometry. The Newton polytope of a statistical model plays a key role. Our results are applied to the hidden Markov model and the general Markov model on a binary tree. PMID:15534224

Pachter, Lior; Sturmfels, Bernd

2004-01-01

367

Behavioral aspects of competition in a three-species rodent guild of coastal southern California  

Microsoft Academic Search

The influence of vole cycles on the demography, spatial organization, and abundance of potential rodent competitors was studied in three California rodents in the laboratory and in the field. Population densities ofMicrotus californicus were inversely correlated with reproductive success in two potential competitors (Reithrodontomys megalotis andMus musculus). Additionally, high-density vole populations forced these species into suboptimal habitats. During low-density vole

Andrew R. Blaustein

1980-01-01

368

The Simultaneous Diversification of South American Echimyid Rodents (Hystricognathi) Based on Complete Cytochrome b Sequences  

Microsoft Academic Search

Variation in the complete nucleotide sequence of the mitochondrial cytochrome b gene was examined for 32 individuals representing 12 supraspecific taxa of South American rodents of the family Echimyidae (Hystricognathi). Representative genera of four other New World hystricognath families, the Old World porcupineHystrix,and the myomorph murid rodentsRattusandMuswere used as outgroups in phylogenetic reconstructions. Monophyly of the family Echimyidae is strongly

Márcia C. Lara; James L. Patton; Maria Nazareth F. da Silva

1996-01-01

369

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

Microsoft Academic Search

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

Martien J. H. Kas; Dale M. Edgar

1998-01-01

370

Humanlike rodent amyloid-?-peptide determines Alzheimer pathology in aged wild-type Octodon degu  

Microsoft Academic Search

It is generally accepted that human Alzheimer's disease (AD) neuropathology markers are completely absent in rodent brains. We report here that an aged wild-type South American rodent, Octodon degu, expresses neuronal ?-amyloid precursor protein (?-APP695) displaying both intracellular and extracellular deposits of amyloid-?-peptide (A?), intracellular accumulations of tau-protein and ubiquitin, a strong astrocytic response and acetylcholinesterase (AChE)-rich pyramidal neurons. The

Nibaldo C. Inestrosa; Ariel E. Reyes; Marcelo A. Chacón; Waldo Cerpa; Aldo Villalón; Juan Montiel; Genevieve Merabachvili; Rebeca Aldunate; Francisco Bozinovic; Francisco Aboitiz

2005-01-01

371

Genome dynamics of Bartonella grahamii in micro-populations of woodland rodents  

Microsoft Academic Search

BACKGROUND: Rodents represent a high-risk reservoir for the emergence of new human pathogens. The recent completion of the 2.3 Mb genome of Bartonella grahamii, one of the most prevalent blood-borne bacteria in wild rodents, revealed a higher abundance of genes for host-cell interaction systems than in the genomes of closely related human pathogens. The sequence variability within the global B.

Eva C Berglund; Christian Ehrenborg; Olga Vinnere Pettersson; Fredrik Granberg; Kristina Näslund; Martin Holmberg; Siv GE Andersson

2010-01-01

372

Two-phase seed dispersal: linking the effects of frugivorous birds and seed-caching rodents  

Microsoft Academic Search

Frugivorous birds disperse the seeds of many fruit-bearing plants, but the fate of seeds after defecation or regurgitation\\u000a is often unknown. Some rodents gather and scatter hoard seeds, and some of these may be overlooked, germinate, and establish\\u000a plants. We show that these two disparate modes of seed dispersal are linked in some plants. Rodents removed large (>25 mg)\\u000a seeds from

Stephen B. Vander Wall; Kellie M. Kuhn; Jennifer R. Gworek

2005-01-01

373

Does weather shape rodents? Climate related changes in morphology of two heteromyid species  

Microsoft Academic Search

Geographical variation in morphometric characters in heteromyid rodents has often correlated with climate gradients. Here,\\u000a we used the long-term database of rodents trapped in the Sevilleta National Wildlife Refuge in New Mexico, USA to test whether\\u000a significant annual changes in external morphometric characters are observed in a region with large variations in temperature\\u000a and precipitation. We looked at the relationships

Mosheh Wolf; Michael Friggens; Jorge Salazar-Bravo

2009-01-01

374

Factors Driving Small Rodents Assemblages from Field Boundaries in Agricultural Landscapes of Western France  

Microsoft Academic Search

In this study, we investigated the factors driving diversity and abundance of small rodent species inhabiting permanent linear\\u000a habitat patches within high-intensified agricultural landscapes of western France. Multivariate (co-inertia) analysis was\\u000a used to analyse relationships of habitat and landscape descriptive variables with rodent records. Two main ecological gradients\\u000a were recognized according to statistical analysis. Relationships of species occurrence with environmental

Butet Alain; Paillat Gilles; Delettre Yannick

2006-01-01

375

Patterns of Rodent Abundance on Open-Space Grasslands in Relation to Suburban Edges  

Microsoft Academic Search

Relatively little is known about the response of grassland rodent populations to urban and subur- ban edges. We live-trapped rodents for three summers on 65 3.1-ha grassland plots on open space of the city of Boulder, Colorado, and compared capture rates among species according to habitat type, percentage of the 40 ha surrounding each plot that was suburbanized, and proximity

Carl E. Bock; Kerri T. Vierling; Sandra L. Haire; John D. Boone; William W. Merkle

2002-01-01

376

Extinction of LINE1 activity coincident with a major mammalian radiation in rodents  

Microsoft Academic Search

LINE-1 transposable elements (L1s) are ubiquitous in mammals and are thought to have remained active since before the mammalian radiation. Only one L1 extinction event, in South American rodents in the genus Oryzomys, has been convincingly demonstrated. Here we examine the phylogenetic limits and evolutionary tempo of that extinction event by characterizing L1s in related rodents. Fourteen genera from five

R. A. Grahn; T. A. Rinehart; M. A. Cantrell; H. A. Wichman

2005-01-01

377

Chemical cues used by prairie rattlesnakes (Crotalus viridis) to follow trails of rodent prey.  

PubMed

Each of 10 prairie rattlesnakes (Crotalus viridis) was exposed to three types of trails after striking rodent prey (Mus musculus). One trail was made with mouse urine, another was made with tap water, and the third consisted of materials from mouse integument. The snakes exhibited trailing behavior only when integumentary trails were available. It was concluded that prairie rattlesnakes do not utilize urinary cues; instead they attend to materials associated with rodent skin and fur. PMID:24264897

Chiszar, D; Melcer, T; Lee, R; Radcliffe, C W; Duvall, D

1990-01-01

378

DECADAL VARIABILITY IN THE TROPICAL PACIFIC CLIMATE  

Microsoft Academic Search

decade long reanalysis of upper ocean temperature and surface meteorology. Indices are defined to reflect the decadal characteristics of the midlatitude and tropical ocean and much of the paper focuses on understanding the fluctuations of these indices. In midlatitudes the analysis reveals structures reminiscent of the Latif-Barnett advective mode. However, in the tropics the climate variability takes on a rather

James A. Carton; Kingtse Mo

379

Tropical Forests and the Global Carbon Cycle  

E-print Network

and inform foresters of sustainable management practices. Periodic cambial dormancy (interruption of growth, Poussart and colleagues are surveying species growing in seasonally dry forests of Brazil, PanamaTropical Forests and the Global Carbon Cycle Pascale Poussart Tropical forests play a key role

Duffy, Thomas S.

380

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

381

Tropical deforestation and atmospheric carbon dioxide  

Microsoft Academic Search

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

R. A. Houghton

1991-01-01

382

TROPICAL MASS EXTINCTIONS AND THE SCIENTIFIC METHOD  

EPA Science Inventory

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

383

Millennial scale climate variability -a tropical perspective  

E-print Network

Millennial scale climate variability - a tropical perspective Climate history and paleoclimate Nov 18, 2011 #12;Climate history and paleoclimate Nov 18, 2011 Outline Introduction: Low latitude and paleoclimate Nov 18, 2011 Tropical climate: precipitation is key! #12;winter summer projected precipitation

Gilli, Adrian

384

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

385

Priorities for Biodiversity Conservation in the Tropics  

NSDL National Science Digital Library

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

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

1998-01-01

386

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

387

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.

388

Field efficacy of deltamethrin for rodent flea control in San Bernardino County, California, USA.  

PubMed

A study was conducted to determine the initial and residual activity of deltamethrin (0.05% dust) applied to rodent burrows (at approximately 14 g/burrow) against fleas in the Silverwood Lake area of San Bernardino County. In initial toxicity (2-d post-treatment), deltamethrin provided 97% flea control and in residual toxicity it resulted in 68% control of the rodent fleas at 15-d post-treatment. The flea fauna consisted of Oropsylla montana (89.9%) and Hoplopsylls anomalus (10.1%). All rodents captured in this study were California ground squirrels, Spermophilus beecheyi. In mark-release-recapture trials, using the microchip identification implant method at the treatment site, the recapture rate of rodents was 29% from 2- to 58-d post-treatment, declining to 21% after 98 d. In the tail-clip method at the treatment site, the recapture rate of 40% at 15-d post-treatment rose to 87% and 73% at 56- and 58-d post-treatment, respectively. At the control site, the recapture rate of 100% at 15-d post-post-treatment dropped to 20% after 98 d. In another trial at Camp Cedar Crest in the Running Springs area, deltamethrin applied to rodent burrows resulted in 70% control of fleas infesting S. beecheyi. Based on the two trials, deltamethrin showed a good initial control of rodent fleas in enzootic or epizootic plague control. PMID:15707280

Mian, Lal S; Hitchcock, James C; Madon, Minoo B; Myers, Charles M

2004-12-01

389

Seroprevalence of Rickettsia typhi and Rickettsia conorii infection among rodents and dogs in Egypt.  

PubMed

A serological survey of 1813 rodent and 549 dog sera, collected from 1979 to 1986 from animals in 16 Egyptian Governorates were tested for antibody to Rickettsia typhi and Rickettsia conorii by the indirect fluorescent antibody test. Only three of 82 (4%) sera from Rattus rattus collected near Aswan had antibody to R. conorii. The prevalence of R. typhi antibody in dog sera was only 0.4% (n = 549) while 25% (n = 547) of Rattus norvegicus and 11% (n = 1138) of R. rattus had measurable antibodies. Among the other rodents, antibody was demonstrated in only 2% (n = 45) of Arvicanthis spp., and 1% (n = 83) of Acomys spp. Collectively, rodents captured in the Nile Delta had a higher prevalence (mean 24% (n = 787] than those captured in the Nile Valley (mean 4% (n = 650]. Antibody to R. typhi was detected in rodents collected in all port cities: ismailiya, 13%; Port Said, 9%; Suez, 9%; Safaga, 16%; Quseir, 32% and Alexandria, 34%. These data showed evidence of R. typhi infection among rodents in widespread geographic localities of Egypt and suggested that infected rodents may be a source of human infections. PMID:2509729

Soliman, A K; Botros, B A; Ksiazek, T G; Hoogstraal, H; Helmy, I; Morrill, J C

1989-10-01

390

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

PubMed

Production cycles in birds are proposed as prime cases of indirect interactions in food webs. They are thought to be driven by predators switching from rodents to bird nests in the crash phase of rodent population cycles. Although rodent cycles are geographically widespread and found in different rodent taxa, bird production cycles appear to be most profound in the high Arctic where lemmings dominate. We hypothesized that this may be due to arctic lemmings inducing stronger predator responses than boreal voles. We tested this hypothesis by estimating predation rates in dummy bird nests during a rodent cycle in low-Arctic tundra. Here, the rodent community consists of a spatially variable mix of one lemming (Lemmus lemmus) and two vole species (Myodes rufocanus and Microtus oeconomus) with similar abundances. In consistence with our hypothesis, lemming peak abundances predicted well crash-phase nest predation rates, whereas the vole abundances had no predictive ability. Corvids were found to be the most important nest predators. Lemmings appear to be accessible to the whole predator community which makes them particularly powerful drivers of food web dynamics. PMID:24173526

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

2013-01-01

391

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

PubMed Central

Bats are the natural reservoirs of a number of high-impact viral zoonoses. We present a quantitative analysis to address the hypothesis that bats are unique in their propensity to host zoonotic viruses based on a comparison with rodents, another important host order. We found that bats indeed host more zoonotic viruses per species than rodents, and we identified life-history and ecological factors that promote zoonotic viral richness. More zoonotic viruses are hosted by species whose distributions overlap with a greater number of other species in the same taxonomic order (sympatry). Specifically in bats, there was evidence for increased zoonotic viral richness in species with smaller litters (one young), greater longevity and more litters per year. Furthermore, our results point to a new hypothesis to explain in part why bats host more zoonotic viruses per species: the stronger effect of sympatry in bats and more viruses shared between bat species suggests that interspecific transmission is more prevalent among bats than among rodents. Although bats host more zoonotic viruses per species, the total number of zoonotic viruses identified in bats (61) was lower than in rodents (68), a result of there being approximately twice the number of rodent species as bat species. Therefore, rodents should still be a serious concern as reservoirs of emerging viruses. These findings shed light on disease emergence and perpetuation mechanisms and may help lead to a predictive framework for identifying future emerging infectious virus reservoirs. PMID:23378666

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

2013-01-01

392

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

PubMed Central

Production cycles in birds are proposed as prime cases of indirect interactions in food webs. They are thought to be driven by predators switching from rodents to bird nests in the crash phase of rodent population cycles. Although rodent cycles are geographically widespread and found in different rodent taxa, bird production cycles appear to be most profound in the high Arctic where lemmings dominate. We hypothesized that this may be due to arctic lemmings inducing stronger predator responses than boreal voles. We tested this hypothesis by estimating predation rates in dummy bird nests during a rodent cycle in low-Arctic tundra. Here, the rodent community consists of a spatially variable mix of one lemming (Lemmus lemmus) and two vole species (Myodes rufocanus and Microtus oeconomus) with similar abundances. In consistence with our hypothesis, lemming peak abundances predicted well crash-phase nest predation rates, whereas the vole abundances had no predictive ability. Corvids were found to be the most important nest predators. Lemmings appear to be accessible to the whole predator community which makes them particularly powerful drivers of food web dynamics. PMID:24173526

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

2013-01-01

393

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

PubMed

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

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

2012-09-01

394

Heterochrony and patterns of cranial suture closure in hystricognath rodents  

PubMed Central

Sutures, joints that allow one bone to articulate with another through intervening fibrous connective tissue, serve as major sites of bone expansion during postnatal craniofacial growth in the vertebrate skull and represent an aspect of cranial ontogeny which may exhibit functional and phylogenetic correlates. Suture evolution among hystricognath rodents, an ecologically diverse group represented here by 26 species, is examined using sequence heterochrony methods, i.e. event pairing and parsimov. Although minor nuances in suture closure sequence exist between species, the overall sequence was found to be conserved both across the hystricognath group and, to an increasing degree, within selected clades. At species level, suture closure pattern exhibited a significant positive correlation with patterns previously reported for hominoids. Patterns for most clades revealed the first sutures to close are those contacting the exoccipital, interparietal, and palatine bones. Heterochronic shifts were found along 19 of 35 branches within the hystricognath phylogeny. The number of shifts per node ranged from one to seven events and, overall, involved 21 of 34 suture sites. The topology generated by parsimony analyses of the event pair matrix yielded only one grouping that was congruent with the evolutionary relationships, compiled from morphological and molecular studies, taken as framework. Sutures contacting the exoccipital displayed the highest levels of most complete closure across all species. Level of suture closure is negatively correlated with cranial length (P < 0.05). Differing life history and locomotory strategies are coupled in part with differing suture closure patterns among several species. PMID:19245501

Wilson, Laura A B; Sánchez-Villagra, Marcelo R

2009-01-01

395

Modulatory effects of metanil yellow on immunity in rodents.  

PubMed

Pathomorphological and immunological studies were carried out on rodents following oral administration of 0, 0.1, 0.25 and 0.5% (w/w) metanil yellow, mixed in diet, for 30 days. No significant change in hematologic parameters and histologic architecture of liver, kidney, mesenteric lymph node, thymus and urinary bladder was observed except for mild desquamation of intestinal villi and moderate changes in Peyer's patches of small intestine with higher doses. Among immunological parameters, significant enhancement in the primary humoral immune response (anti-SRBC IgM plaque forming cells of spleen) was observed with the lowest dose of metanil yellow while higher doses produced opposing effects. An elevated cutaneous delayed type hypersensitivity (DTH) reaction to SRBC was seen in 0.1% metanil yellow treated animals but higher doses did not influence the reaction. The treatment also caused changes in functional capabilities of macrophages. Although these immune alterations could hardly influence the local immunity of gut, as measured by the capacity of animals to cause rejection of Nippostrongylus brasiliensis parasite, the potential to modulate the immunity in general by metanil yellow however assumes considerable biological significance. PMID:1459615

Shanker, R; Dogra, R K; Khanna, S; Srivastava, S N; Shukla, L J; Gupta, S; Katiyar, J C

1992-05-01

396

Acute Blast Injury Reduces Brain Abeta in Two Rodent Species  

PubMed Central

Blast-induced traumatic brain injury (TBI) has been a major cause of morbidity and mortality in the conflicts in Iraq and Afghanistan. How the primary blast wave affects the brain is not well understood. In particular, it is unclear whether blast injures the brain through mechanisms similar to those found in non-blast closed impact injuries (nbTBI). The ?-amyloid (A?) peptide associated with the development of Alzheimer’s disease is elevated acutely following TBI in humans as well as in experimental animal models of nbTBI. We examined levels of brain A? following experimental blast injury using enzyme-linked immunosorbent assays for A? 40 and 42. In both rat and mouse models of blast injury, rather than being increased, endogenous rodent brain A? levels were decreased acutely following injury. Levels of the amyloid precursor protein (APP) were increased following blast exposure although there was no evidence of axonal pathology based on APP immunohistochemical staining. Unlike the findings in nbTBI animal models, levels of the ?-secretase, ?-site APP cleaving enzyme 1, and the ?-secretase component presenilin-1 were unchanged following blast exposure. These studies have implications for understanding the nature of blast injury to the brain. They also suggest that strategies aimed at lowering A? production may not be effective for treating acute blast injury to the brain. PMID:23267342

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

2012-01-01

397

Rodent herpesvirus Peru encodes a secreted chemokine decoy receptor.  

PubMed

Viruses have long been studied not only for their pathology and associated disease but also as model systems for understanding cellular and immunological processes. Rodent herpesvirus Peru (RHVP) is a recently characterized rhadinovirus related to murine gammaherpesvirus 68 (MHV68) and Kaposi's sarcoma-associated herpesvirus (KSHV) that establishes acute and latent infection in laboratory mice. RHVP encodes numerous unique proteins that we hypothesize might facilitate host immune evasion during infection. We report here that open reading frame (ORF) R17 encodes a high-affinity chemokine binding protein that broadly recognizes human and murine CC and C chemokines. The interaction of R17 with chemokines is generally characterized by rapid association kinetics, and in the case of CCL3, CCL4, CCL5, CCL24, and XCL1, extremely stable complexes are formed. Functionally, R17 potently inhibited CCL2-driven chemotaxis of the human monocytic cell line THP-1, CCL3-driven chemotaxis of peripheral blood mononuclear cells, and CCL2-mediated calcium flux. Our studies also reveal that R17 binds to glycosaminoglycans (GAGs) in a process dependent upon two BBXB motifs and that chemokine and GAG binding can occur simultaneously at distinct sites. Collectively, these studies suggest that R17 may play a role in RHVP immune evasion through the targeted sabotage of chemokine-mediated immune surveillance. PMID:24173234

Lubman, Olga Y; Cella, Marina; Wang, Xinxin; Monte, Kristen; Lenschow, Deborah J; Huang, Yina H; Fremont, Daved H

2014-01-01

398

Rodents and Leptospira transmission risk in Terceira island (Azores).  

PubMed

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 highest bacteriological (82.9%) and serological (90.9%) rates, being strictly related to serovar arborea. Black rats were involved in the dispersion of all isolated L. interrogans sensu lato serovars (arborea, copenhageni and icterohaemorrhagiae). Logistic regression analysis and non-metric multi-dimensional scaling, relating Leptospira infection with biological and environmental variables, expressed that adult males Mus domesticus, sexually active and living in humid biotopes, mainly above 500 m, are the most likely reservoirs. This study emphasizes the role of house-mice in the epidemiology of leptospirosis in Terceira and the need of reducing the risk of Leptospira transmission through integrated control programmes, primarily focusing on adult house-mice in peri-domestic environments, before the breeding season. PMID:11484805

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

2000-01-01

399

OCT-aided anastomosis platform study in the rodent model  

NASA Astrophysics Data System (ADS)

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

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

2014-02-01

400

Rodent Herpesvirus Peru Encodes a Secreted Chemokine Decoy Receptor  

PubMed Central

Viruses have long been studied not only for their pathology and associated disease but also as model systems for understanding cellular and immunological processes. Rodent herpesvirus Peru (RHVP) is a recently characterized rhadinovirus related to murine gammaherpesvirus 68 (MHV68) and Kaposi's sarcoma-associated herpesvirus (KSHV) that establishes acute and latent infection in laboratory mice. RHVP encodes numerous unique proteins that we hypothesize might facilitate host immune evasion during infection. We report here that open reading frame (ORF) R17 encodes a high-affinity chemokine binding protein that broadly recognizes human and murine CC and C chemokines. The interaction of R17 with chemokines is generally characterized by rapid association kinetics, and in the case of CCL3, CCL4, CCL5, CCL24, and XCL1, extremely stable complexes are formed. Functionally, R17 potently inhibited CCL2-driven chemotaxis of the human monocytic cell line THP-1, CCL3-driven chemotaxis of peripheral blood mononuclear cells, and CCL2-mediated calcium flux. Our studies also reveal that R17 binds to glycosaminoglycans (GAGs) in a process dependent upon two BBXB motifs and that chemokine and GAG binding can occur simultaneously at distinct sites. Collectively, these studies suggest that R17 may play a role in RHVP immune evasion through the targeted sabotage of chemokine-mediated immune surveillance. PMID:24173234

Lubman, Olga Y.; Cella, Marina; Wang, Xinxin; Monte, Kristen; Lenschow, Deborah J.; Huang, Yina H.

2014-01-01

401

Traumatic Brain Injury - Modeling Neuropsychiatric Symptoms in Rodents  

PubMed Central

Each year in the US, ?1.5 million people sustain a traumatic brain injury (TBI). Victims of TBI can suffer from chronic post-TBI symptoms, such as sensory and motor deficits, cognitive impairments including problems with memory, learning, and attention, and neuropsychiatric symptoms such as depression, anxiety, irritability, aggression, and suicidal rumination. Although partially associated with the site and severity of injury, the biological mechanisms associated with many of these symptoms – and why some patients experience differing assortments of persistent maladies – are largely unknown. The use of animal models is a promising strategy for elucidation of the mechanisms of impairment and treatment, and learning, memory, sensory, and motor tests have widespread utility in rodent models of TBI and psychopharmacology. Comparatively, behavioral tests for the evaluation of neuropsychiatric symptomatology are rarely employed in animal models of TBI and, as determined in this review, the results have been inconsistent. Animal behavioral studies contribute to the understanding of the biological mechanisms by which TBI is associated with neurobehavioral symptoms and offer a powerful means for pre-clinical treatment validation. Therefore, further exploration of the utility of animal behavioral tests for the study of injury mechanisms and therapeutic strategies for the alleviation of emotional symptoms are relevant and essential. PMID:24109476

Malkesman, Oz; Tucker, Laura B.; Ozl, Jessica; McCabe, Joseph T.

2013-01-01

402

What Can We Learn from Rodents about Prolactin in Humans?  

PubMed Central

Prolactin (PRL) is a 23-kDa protein hormone that binds to a single-span membrane receptor, a member of the cytokine receptor superfamily, and exerts its action via several interacting signaling pathways. PRL is a multifunctional hormone that affects multiple reproductive and metabolic functions and is also involved in tumorigenicity. In addition to being a classical pituitary hormone, PRL in humans is produced by many tissues throughout the body where it acts as a cytokine. The objective of this review is to compare and contrast multiple aspects of PRL, from structure to regulation, and from physiology to pathology in rats, mice, and humans. At each juncture, questions are raised whether, or to what extent, data from rodents are relevant to PRL homeostasis in humans. Most current knowledge on PRL has been obtained from studies with rats and, more recently, from the use of transgenic mice. Although this information is indispensable for understanding PRL in human health and disease, there is sufficient disparity in the control of the production, distribution, and physiological functions of PRL among these species to warrant careful and judicial extrapolation to humans. PMID:18057139

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

2008-01-01

403

Electrochemical techniques for subsecond neurotransmitter detection in live rodents.  

PubMed

Alterations in neurotransmission have been implicated in numerous neurodegenerative and neuropsychiatric disorders, including Alzheimer disease, Parkinson disease, epilepsy, and schizophrenia. Unfortunately, few techniques support the measurement of real-time changes in neurotransmitter levels over multiple days, as is essential for ethologic and pharmacodynamic testing. Microdialysis is commonly used for these research paradigms, but its poor temporal and spatial resolution make this technique inadequate for measuring the rapid dynamics (milliseconds to seconds) of fast signaling neurotransmitters, such as glutamate and acetylcholine. Enzymatic microelectrode arrays (biosensors) coupled with electrochemical recording techniques have demonstrated fast temporal resolution (less than 1 s), excellent spatial resolution (micron-scale), low detection limits (?200 nM), and minimal damage (50 to 100 ?m) to surrounding brain tissue. Here we discuss the benefits, methods, and animal welfare considerations of using platinum microelectrodes on a ceramic substrate for enzyme-based electrochemical recording techniques for real-time in vivo neurotransmitter recordings in both anesthetized and awake, freely moving rodents. PMID:25296011

Hascup, Kevin N; Hascup, Erin R

2014-01-01

404

Metabolic phenotyping guidelines: assessing glucose homeostasis in rodent models.  

PubMed

The pathophysiology of diabetes as a disease is characterised by an inability to maintain normal glucose homeostasis. In type 1 diabetes, this is due to autoimmune destruction of the pancreatic ?-cells and subsequent lack of insulin production, and in type 2 diabetes it is due to a combination of both insulin resistance and an inability of the ?-cells to compensate adequately with increased insulin release. Animal models, in particular genetically modified mice, are increasingly being used to elucidate the mechanisms underlying both type 1 and type 2 diabetes, and as such the ability to study glucose homeostasis in vivo has become an essential tool. Several techniques exist for measuring different aspects of glucose tolerance and each of these methods has distinct advantages and disadvantages. Thus the appropriate methodology may vary from study to study depending on the desired end-points, the animal model, and other practical considerations. This review outlines the most commonly used techniques for assessing glucose tolerance in rodents and details the factors that should be taken into account in their use. Representative scenarios illustrating some of the practical considerations of designing in vivo experiments for the measurement of glucose homeostasis are also discussed. PMID:25056117

Bowe, James E; Franklin, Zara J; Hauge-Evans, Astrid C; King, Aileen J; Persaud, Shanta J; Jones, Peter M

2014-09-01

405

Synthetic cathinones and their rewarding and reinforcing effects in rodents  

PubMed Central

Synthetic cathinones, colloquially referred to as “bath salts”, are derivatives of the psychoactive alkaloid cathinone found in Catha edulis (Khat). Since the mid-to-late 2000’s, these amphetamine-like psychostimulants have gained popularity amongst drug users due to their potency, low cost, ease of procurement, and constantly evolving chemical structures. Concomitant with their increased use is the emergence of a growing collection of case reports of bizarre and dangerous behaviors, toxicity to numerous organ systems, and death. However, scientific information regarding the abuse liability of these drugs has been relatively slower to materialize. Recently we have published several studies demonstrating that laboratory rodents will readily self-administer the “first generation” synthetic cathinones methylenedioxypyrovalerone (MDPV) and methylone via the intravenous route, in patterns similar to those of methamphetamine. Under progressive ratio schedules of reinforcement, the rank order of reinforcing efficacy of these compounds are MDPV ? methamphetamine > methylone. MDPV and methylone, as well as the “second generation” synthetic cathinones ?-pyrrolidinovalerophenone (?-PVP) and 4-methylethcathinone (4-MEC), also dose-dependently increase brain reward function. Collectively, these findings indicate that synthetic cathinones have a high abuse and addiction potential and underscore the need for future assessment of the extent and duration of neurotoxicity induced by these emerging drugs of abuse.

Watterson, Lucas R.; Olive, M. Foster

2014-01-01

406

A fundamental oscillatory state of isolated rodent hippocampus  

PubMed Central

Population neuronal rhythms of various frequencies are observed in the rodent hippocampus during distinct behavioural states. However, the question of whether the hippocampus exhibits properties of spontaneous rhythms and population synchrony in isolation has not been definitively answered. To address this, we developed a novel preparation for studying neuronal rhythms in a relatively large hippocampal tissue in vitro. We isolated the whole hippocampus from mice up to 28 days postnatal age, removing the dentate gyrus while preserving the functional CA3-to-CA1 connections. Placing the hippocampal isolate in a perfusion chamber for electrophysiological assessment extracellular recordings from the CA1 revealed rhythmic field potential of 0.5 to ? 4 Hz that occurred spontaneously and propagated along the ventro-dorsal hippocampal axis. We provide convergent evidence, via measurements of extracellular pH and K+, recordings of synaptic and intracellular activities and morphological assessments, verifying that these rhythms were not the consequence of hypoxia. Data obtained via simultaneous extracellular and patch clamp recordings suggest that the spontaneous rhythms represent a summation of GABAergic IPSPs originating from pyramidal neurons, which result from synchronous discharges of GABAergic inhibitory interneurons. Similar spontaneous field rhythms were also observed in the hippocampal isolate prepared from young gerbils and rats. Based on these data, we postulate that the spontaneous rhythms represent a fundamental oscillatory state of the hippocampal circuitry isolated from extra-hippocampal inputs. PMID:11956340

Wu, Chiping; Shen, Hui; Luk, Wah Ping; Zhang, Liang

2002-01-01

407

Validating Excised Rodent Lungs for Functional Hyperpolarized Xenon-129 MRI  

PubMed Central

Ex vivo rodent lung models are explored for physiological measurements of respiratory function with hyperpolarized (hp) 129Xe MRI. It is shown that excised lung models allow for simplification of the technical challenges involved and provide valuable physiological insights that are not feasible using in vivo MRI protocols. A custom designed breathing apparatus enables MR images of gas distribution on increasing ventilation volumes of actively inhaled hp 129Xe. Straightforward hp 129Xe MRI protocols provide residual lung volume (RV) data and permit for spatially resolved tracking of small hp 129Xe probe volumes during the inhalation cycle. Hp 129Xe MRI of lung function in the excised organ demonstrates the persistence of post mortem airway responsiveness to intravenous methacholine challenges. The presented methodology enables physiology of lung function in health and disease without additional regulatory approval requirements and reduces the technical and logistical challenges with hp gas MRI experiments. The post mortem lung functional data can augment histological measurements and should be of interest for drug development studies. PMID:24023683

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

2013-01-01

408

Enzymatic activity of rodents acclimated to cold and long scotophase  

NASA Astrophysics Data System (ADS)

Rodents representative of a diurnal species ( Rhabdomys pumilio) as well as a nocturnal species ( Praomys natalensis) were acclimated to cold (Ta = 8°C) at a photoperiod of LD 12:12 and a long scotophase (LD 8; 16) at a temperature of 25° C(Ta). Control groups were kept for both species at Ta = 25° C and LD 12:12 and winter acclimated individuals were obtained during July and August to serve as further reference. Blood samples obtained from the tail were analysed for enzymes representative of three major biochemical pathways. The enzymatic activity of LDH (glycolytic pathway), MDH (Krebs cycle) and G6PDH (hexose monophosphate shunt, as an indicator of gonadal activity) were monitored to represent metabolic activity of the respective cycles. Cold acclimated as well as winter acclimatized mice revealed similar enzymatic patterns for both species and significant increases in LDH and MDH were recorded with a concurrent decrease in G6PDH activity. Specimens exposed to long scotophase exhibited similar enzymatic patterns for both species studied, but enzymatic activity was higher than those of cold acclimated individuals. From these results it is concluded that cold as well as long scotophase induce metabolic adaptations through biochemical activity in the experimental animals. The effect of long scotophase is assumed to be an important factor in the induction of winter acclimatization.

Fourie, F. Le R.; Haim, A.

1980-09-01

409

Near-infrared light penetration profile in the rodent brain  

PubMed Central

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

Abdo, Ammar; Ersen, Ali; Sahin, Mesut

2013-01-01

410

Odor supported place cell model and goal navigation in rodents.  

PubMed

Experiments with rodents demonstrate that visual cues play an important role in the control of hippocampal place cells and spatial navigation. Nevertheless, rats may also rely on auditory, olfactory and somatosensory stimuli for orientation. It is also known that rats can track odors or self-generated scent marks to find a food source. Here we model odor supported place cells by using a simple feed-forward network and analyze the impact of olfactory cues on place cell formation and spatial navigation. The obtained place cells are used to solve a goal navigation task by a novel mechanism based on self-marking by odor patches combined with a Q-learning algorithm. We also analyze the impact of place cell remapping on goal directed behavior when switching between two environments. We emphasize the importance of olfactory cues in place cell formation and show that the utility of environmental and self-generated olfactory cues, together with a mixed navigation strategy, improves goal directed navigation. PMID:18431616

Kulvicius, Tomas; Tamosiunaite, Minija; Ainge, James; Dudchenko, Paul; Wörgötter, Florentin

2008-12-01

411

Optically induced occlusion of single blood vessels in rodent neocortex.  

PubMed

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

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

2013-12-01

412

Comparative energetics of the subterranean Ctenomys rodents: breaking patterns.  

PubMed

Subterranean mammals show lower mass-independent basal metabolic rates (BMRs). Several competing hypotheses were suggested to explain how microenvironmental conditions and underground life affect subterranean mammalian energetics. Two of these are the thermal stress and the cost-of-burrowing hypotheses. The thermal stress hypothesis posits that a lower mass-independent BMR reduces overheating in burrows where convective and evaporative heat loss is low, whereas the cost-of-burrowing hypothesis states that a lower mass-independent BMR may compensate for the high energy expenditure of digging. In this article, we assessed the relationship between BMR of Ctenomys and environmental variables through conventional statistics as well as independent contrasts. Moreover, we tested both the thermal stress and the cost-of-burrowing hypotheses at an interspecific level in a very homogeneous genus of subterranean rodents, the South American genus Ctenomys. We compared species from different geographic localities that have contrasting habitat conditions. We measured BMR through open-flow respirometry. After conventional as well as independent contrast analyses, our results support neither the thermal stress nor the cost-of-burrowing hypotheses. We observed that only body mass affects the variability in BMR. Contrasting climatic and soil conditions, habitat productivity, and net primary productivity were not correlated with BMR variability. We suggested that, because BMR and maximum metabolic rates (MMRs) are correlated, low BMRs among Ctenomys species could also be determined by factors that affect MMR rather than BMR. PMID:19327041

Luna, Facundo; Antenucci, C Daniel; Bozinovic, Francisco

2009-01-01

413

Rodent and ruminant ingestive response to flavonoids in Euphorbia esula.  

PubMed

Euphorbia esula, common name leafy spurge, was chemically evaluated for aversive phytochemicals that appear to minimize herbivory by rodents and cattle. A middle-layer extract elicited food aversions in rats as did the petroleum ether extract of the initial methanol extract. Kaempferol-3-0-beta-glucuronic acid and quercetin-3-0-beta-glucuronic acid were separated and identified from the middle-layer residue. This study is the first report of quercetin-3-0-beta-glucuronic acid in leafy spurge. Together these flavonoidal glucosides were mildly aversive to rats but showed less aversive activity when tested separately. The middle-layer extract produced no aversive response from cattle, while the petroleum ether extract elicited strong aversions in cattle. Flavonoidal compounds from leafy spurge that were aversive to rats, a monogastric mammal, were not aversive to cattle, a ruminant. Microbial degradation of the compounds before they reach the intestines and are absorbed into the bloodstream is likely a key advantage for cattle compared to rats. PMID:12857022

Halaweish, F; Kronberg, S; Rice, J A

2003-05-01

414

Receptor tyrosine kinase inhibitors in rodent pulmonary hypertension.  

PubMed

Pulmonary hypertension (PH) is a disorder characterized by vascular remodeling and proliferation, a phenotype dependent upon unimpeded growth factor and kinase pathway activation with strong similarities to malignant tumors. This chapter details our novel application of the multikinase inhibitor, sorafenib, in rodent models of PH to improved hemodynamic parameters and attenuates PH structural changes1. Sorafenib is a Raf kinase inhibitor and our biochemical and genomic evidence supported the potential involvement of the MAPK cascade system and TGFB3 in PH development and the response to therapy. Integration of expression genomic analyses coupled with intense bioinformatics identified gene expression and ontology signatures in the development of PH and implicated the role of cytoskeletal protein such as caldesmon or nmMLCK as potentially key participants in PH-induced vascular remodeling and proliferation. Our studies suggest the PKI sorafenib as a potentially novel treatment for severe PH with the MAPK cascade a potential canonical target profoundly effecting vascular cytoskeletal -rearrangements and remodeling1. PMID:20204746

Moreno-Vinasco, Liliana; Garcia, Joe G N

2010-01-01

415

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

416

Tropical Cyclones as a Critical Phenomenon  

E-print Network

It has been proposed that the number of tropical cyclones as a function of the energy they release is a decreasing power-law function, up to a characteristic energy cutoff determined by the spatial size of the ocean basin in which the storm occurs. This means that no characteristic scale exists for the energy of tropical cyclones, except for the finite-size effects induced by the boundaries of the basins. This has important implications for the physics of tropical cyclones. We discuss up to what point tropical cyclones are related to critical phenomena (in the same way as earthquakes, rainfall, etc.), providing a consistent picture of the energy balance in the system. Moreover, this perspective allows one to visualize more clearly the effects of global warming on tropical-cyclone occurrence.

Corral, A

2011-01-01

417

Geographic variation in rodent-flea relationships in the presence of black-tailed prairie dog colonies.  

PubMed

We characterized the relationship between fleas and their rodent hosts in the presence of prairie dog colonies and compared them to adjacent assemblages away from colonies. We evaluated the rodent-flea relationship by quantifying prevalence, probability of infestation, flea load, and intensity of fleas on rodents. As prairie dog burrows provide refugia for fleas, we hypothesized that prevalence, flea load, and intensity would be higher for rodents that are associated with black-tailed prairie dog colonies. Rodents were trapped at off- and on-colony grids, resulting in the collection of 4,509 fleas from 1,430 rodents in six study areas. The rodent community composition varied between these study areas. Flea species richness was not different between prairie dog colonies and the surrounding grasslands (p = 0.883) but was positively correlated with rodent species richness (p = 0.055). Prairie dog colonies did not increase the prevalence of fleas (p > 0.10). Flea loads on rodents did not vary between off- and on-colony grids at three of the study areas (p > 0.10). Based on the prevalence, infestation rates, and flea loads, we identified Peromyscus maniculatus, Onychomys leucogaster, and two Neotoma species as important rodent hosts for fleas and Aetheca wagneri, Orchopeus leucopus, Peromyscopsylla hesperomys, Pleochaetis exilis, and Thrassisfotus as the most important fleas associated with these rodents. Prairie dog colonies did not seem to facilitate transmission of fleas between rodent hosts, and the few rodent-flea associations exhibited significant differences between off- and on-colony grids. PMID:18697322

Thiagarajan, Bala; Cully, Jack F; Loughin, Thomas M; Montenieri, John A; Gage, Kenneth L

2008-06-01

418

Tropical pulmonary eosinophilia - A review  

PubMed Central

Tropical pulmonary eosinophilia (TPE) is a syndrome of wheezing, fever and eosiniphilia seen predominantly in the Indian subcontinent and other tropical areas. Its etiological link with Wuchereria bancrofti and Brugia malayi has been well established. The pathogenesis is due to an exaggerated immune response to the filarial antigens which includes type I, type III and type IV reactions with eosinophils playing a pivotal role. Peripheral blood eosinophilia is usually striking with levels over 3000/?l being common. High serum levels of IgE and filarial-specific IgE and IgG are also found. The pathology may vary from an acute eosinophilic alveolitis to histiocytic infiltration depending on the stage of the disease. While earlier studies had suggested that the disease runs a benign course, more recent work has shown that untreated TPE could result in a fair degree of respiratory morbidity. Pulmonary function tests may show a mixed restrictive and obstructive abnormality with a reduction in diffusion capacity. The bronchoalveolar lavage (BAL) eosinophil count has a negative correlation with the diffusion capacity. Treatment consists of diethylcarbamazine (DEC) for at least three weeks. Despite treatment with DEC, about 20 per cent of patients may relapse. Steroids have shown to have a beneficial effect but the exact dose and duration is yet to be confirmed by randomized controlled trials. A specific and easily available marker is required for TPE in order to distinguish it from other parasitic and non-parasitic causes of pulmonary eosinophilia. PMID:24135173

Mullerpattan, Jai B.; Udwadia, Zarir F.; Udwadia, Farokh E.

2013-01-01

419

Tropical Rainfall Measuring Mission (TRMM)  

NSDL National Science Digital Library

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

420

The diversity of microparasites of rodents: a comparative analysis that helps in identifying rodent-borne rich habitats in Southeast Asia  

PubMed Central

Background Predicting habitats prone to favor disease transmission is challenging due to confounding information on habitats, reservoirs, and diseases. Comparative analysis, which aims at investigating ecological and evolutionary patterns among species, is a tool that may help. The emergence of zoonotic pathogens is a major health concern and is closely linked to habitat modifications by human activities. Risk assessment requires a better knowledge of the interactions between hosts, parasites, and the landscape. Methods We used information from a field spatial study that investigated the distribution of murid rodents, in various habitats of three countries in Southeast Asia, in combination with their status of infection by 10 taxa of microparasites obtained from the literature. Microparasite species richness was calculated by rodent species on 20,272 rodents of 13 species. Regression tree models and generalized linear models were used to explain microparasite diversity by the average distance between the trapping site and five categories of land cover: forest, steep agriculture land, flat agriculture land, water, and built-up surfaces. Another variable taken into account was the slope. Results We found that microparasite diversity was positively associated with flat agriculture land, in this context mainly rice fields, and negatively associated with slope. Microparasite diversity decreased sharply a 100 m or less from flat agriculture land. Conclusion We conclude that there is high microparasite circulation in rodents of flooded farmlands, meaning possibly a higher risk of disease for human inhabitants. PMID:23577229

Bordes, Frederic; Herbreteau, Vincent; Dupuy, Stephane; Chaval, Yannick; Tran, Annelise; Morand, Serge

2013-01-01

421

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. PMID:21911980

Mathew, Ashish Jacob; George, Jacob

2011-01-01

422

Ventilatory accommodation of changing oxygen demand in sciurid rodents.  

PubMed

Ventilation was measured across a range of O2 consumption rates in four sciurid rodents: Tamias minimus (47 g), Spermophilus lateralis (189 g), S. beecheyi (531 g), and Marmota flaviventris juveniles (1054 g) and adults (2989 g). Maximum thermogenic oxygen consumption was measured for all but adult M. flaviventris. Aerobic scopes (maximum/minimum O2 consumption rates) were 4.6, 3.8, 5.4, and 4.8 in T. minimus, S. lateralis, S. beecheyi, and juvenile M. flaviventris, respectively. Aerobic scope was at least 4.1 in adult M. flaviventris. Ventilatory accommodation of changing O2 consumption rate was qualitatively similar in the four species, with the bulk of accommodation resulting from changes in minute volume. Nevertheless, there were significant differences in the relative importance of frequency, tidal volume, and O2 extraction in accommodation. In all species, frequency and minute volume were strongly correlated to O2 consumption rate. Tidal volume was significantly correlated to O2 consumption rate in T. minimus and S. beecheyi, but not in the other species. Oxygen extraction was not significantly correlated to O2 consumption rate in any species. Analysis of factorial ventilation changes across a standardized 3.8-fold change in O2 consumption rate revealed significant differences among species in frequency and O2 extraction, but not in tidal or minute volume. When compared to a generalized allometry for mammalian resting ventilation, the four sciurid species had consistently lower respiration frequency and higher O2 extraction than predicted, perhaps because the sciurid measurements were made on unrestrained animals. There was no indication that ventilation constrained maximum O2 consumption rate. PMID:1494030

Chappell, M A

1992-01-01

423

Expensive Brains: “Brainy” Rodents have Higher Metabolic Rate  

PubMed Central

Brains are the centers of the nervous system of animals, controlling the organ systems of the body and coordinating responses to changes in the ecological and social environment. The evolution of traits that correlate with cognitive ability, such as relative brain size is thus of broad interest. Brain mass relative to body mass (BM) varies among mammals, and diverse factors have been proposed to explain this variation. A recent study provided evidence that energetics play an important role in brain evolution (Isler and van Schaik, 2006). Using composite phylogenies and data drawn from multiple sources, these authors showed that basal metabolic rate (BMR) correlates with brain mass across mammals. However, no such relationship was found within rodents. Here we re-examined the relationship between BMR and brain mass within Rodentia using a novel species-level phylogeny. Our results are sensitive to parameter evaluation; in particular how species mass is estimated. We detect no pattern when applying an approach used by previous studies, where each species BM is represented by two different numbers, one being the individual that happened to be used for BMR estimates of that species. However, this approach may compromise the analysis. When using a single value of BM for each species, whether representing a single individual, or available species mean, our findings provide evidence that brain mass (independent of BM) and BMR are correlated. These findings are thus consistent with the hypothesis that large brains evolve when the payoff for increased brain mass is greater than the energetic cost they incur. PMID:21811456

Sobrero, Raúl; May-Collado, Laura J.; Agnarsson, Ingi; Hernández, Cristián E.

2011-01-01

424

Lung imaging in rodents using dual energy micro-CT  

NASA Astrophysics Data System (ADS)

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

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

2012-03-01

425

Stress induced obesity: lessons from rodent models of stress  

PubMed Central

Stress was once defined as the non-specific result of the body to any demand or challenge to homeostasis. A more current view of stress is the behavioral and physiological responses generated in the face of, or in anticipation of, a perceived threat. The stress response involves activation of the sympathetic nervous system and recruitment of the hypothalamic-pituitary-adrenal (HPA) axis. When an organism encounters a stressor (social, physical, etc.), these endogenous stress systems are stimulated in order to generate a fight-or-flight response, and manage the stressful situation. As such, an organism is forced to liberate energy resources in attempt to meet the energetic demands posed by the stressor. A change in the energy homeostatic balance is thus required to exploit an appropriate resource and deliver useable energy to the target muscles and tissues involved in the stress response. Acutely, this change in energy homeostasis and the liberation of energy is considered advantageous, as it is required for the survival of the organism. However, when an organism is subjected to a prolonged stressor, as is the case during chronic stress, a continuous irregularity in energy homeostasis is considered detrimental and may lead to the development of metabolic disturbances such as cardiovascular disease, type II diabetes mellitus and obesity. This concept has been studied extensively using animal models, and the neurobiological underpinnings of stress induced metabolic disorders are beginning to surface. However, different animal models of stress continue to produce divergent metabolic phenotypes wherein some animals become anorexic and lose body mass while others increase food intake and body mass and become vulnerable to the development of metabolic disturbances. It remains unclear exactly what factors associated with stress models can be used to predict the metabolic outcome of the organism. This review will explore a variety of rodent stress models and discuss the elements that influence the metabolic outcome in order to further extend our understanding of stress-induced obesity. PMID:23898237

Patterson, Zachary R.; Abizaid, Alfonso

2013-01-01

426

Lung function measurements in rodents in safety pharmacology studies.  

PubMed

The ICH guideline S7A requires safety pharmacology tests including measurements of pulmonary function. In the first step - as part of the "core battery" - lung function tests in conscious animals are requested. If potential adverse effects raise concern for human safety, these should be explored in a second step as a "follow-up study." For these two stages of safety pharmacology testing, both non-invasive and invasive techniques are needed which should be as precise and reliable as possible. A short overview of typical in vivo measurement techniques is given, their advantages and disadvantages are discussed and out of these the non-invasive head-out body plethysmography and the invasive but repeatable body plethysmography in orotracheally intubated rodents are presented in detail. For validation purposes the changes in the respective parameters such as tidal midexpiratory flow (EF(50)) or lung resistance have been recorded in the same animals in typical bronchoconstriction models and compared. In addition, the technique of head-out body plethysmography has been shown to be useful to measure lung function in juvenile rats starting from day two of age. This allows safety pharmacology testing and toxicological studies in juvenile animals as a model for the young developing organism as requested by the regulatory authorities (e.g., EMEA Guideline 1/2008). It is concluded that both invasive and non-invasive pulmonary function tests are capable of detecting effects and alterations on the respiratory system with different selectivity and area of operation. The use of both techniques in a large number of studies in mice and rats in the last years have demonstrated that they provide useful and reliable information on pulmonary mechanics in safety pharmacology and toxicology testing, in investigations of respiratory disorders, and in pharmacological efficacy studies. PMID:22973226

Hoymann, Heinz Gerd

2012-01-01

427

Ghrelin prevents the development of experimental diabetic neuropathy in rodents.  

PubMed

Ghrelin is an acylated peptide discovered in gastric extracts as an endogenous ligand for the growth hormone secretagogue (GHS) receptor. This peptide increases food intake and growth hormone secretion, suppresses inflammation and oxidative stress, and promotes cell survival and proliferation. Our study investigated the pharmacological effect of ghrelin in the prevention of polyneuropathy in streptozotocin-induced diabetes mellitus in C57BL/6N mice, GHS receptor-deficient mice, and growth hormone-deficient rats. Ghrelin or desacyl-ghrelin was administered daily for four weeks immediately after disease onset. The effects of ghrelin on food intake, body weight, blood glucose and plasma insulin levels, nerve conduction velocities, temperature sensation, and 8-isoprostaglandin F2? (8-iso-PGF2?) levels were examined. We found that ghrelin administration did not change food intake, body weight gain, blood glucose levels, or plasma insulin levels in C57BL/6N mice in comparison with mice treated with saline or desacyl-ghrelin administration. Ghrelin administration, but not desacyl-ghrelin, prevented motor and sensory polyneuropathy and reduced the plasma concentrations of 8-iso-PGF2? in C57BL/6N mice. Ghrelin also prevented the reduction in nerve conduction velocities in growth hormone-deficient rats, but not in GHS receptor-knockout mice. In conclusion, ghrelin administration in a rodent model of diabetes prevented polyneuropathy, and this effect was mediated through the GHS receptor and was independent of growth hormone. The protection against the development of experimental diabetic polyneuropathy by ghrelin could be key in preventing this otherwise intractable disorder. PMID:23396232

Tsuchimochi, Wakaba; Kyoraku, Itaru; Yamaguchi, Hideki; Toshinai, Koji; Shiomi, Kazutaka; Kangawa, Kenji; Nakazato, Masamitsu

2013-02-28

428

Naturalistic rodent models of chronic early-life stress.  

PubMed

A close association between early-life experience and cognitive and emotional outcomes is found in humans. In experimental models, early-life experience can directly influence a number of brain functions long-term. Specifically, and often in concert with genetic background, experience regulates structural and functional maturation of brain circuits and alters individual neuronal function via large-scale changes in gene expression. Because adverse experience during sensitive developmental periods is often associated with neuropsychiatric disease, there is an impetus to create realistic models of distinct early-life experiences. These can then be used to study causality between early-life experiential factors and cognitive and emotional outcomes, and to probe the underlying mechanisms. Although chronic early-life stress has been linked to the emergence of emotional and cognitive disorders later in life, most commonly used rodent models of involve daily maternal separation and hence intermittent early-life stress. We describe here a naturalistic and robust chronic early-life stress model that potently influences cognitive and emotional outcomes. Mice and rats undergoing this stress develop structural and functional deficits in a number of limbic-cortical circuits. Whereas overt pathological memory impairments appear during adulthood, emotional and cognitive vulnerabilities emerge already during adolescence. This naturalistic paradigm, widely adopted around the world, significantly enriches the repertoire of experimental tools available for the study of normal brain maturation and of cognitive and stress-related disorders including depression, autism, post-traumatic stress disorder, and dementia. © 2014 Wiley Periodicals, Inc. Dev Psychobiol 56: 1675-1688, 2014. PMID:24910169

Molet, Jenny; Maras, Pamela M; Avishai-Eliner, Sarit; Baram, Tallie Z

2014-12-01

429

Cytokine-independent repression of rodent Ntcp in obstructive cholestasis.  

PubMed

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 CBDL rats and mice was either performed directly with tumor necrosis factor alpha (etanercept) or interleukin 1 beta inactivation (anakinra/AMG 719) or indirectly Kupffer cell depletion via intraperitoneal administration of liposome-encapsulated dichloromethylene bisphosphonate. Protein and messenger RNA (mRNA) expression of Ntcp and short heterodimer partner (SHP) were analyzed via Western and Northern blotting. Key regulators of Ntcp (hepatocyte nuclear factor 1 alpha [HNF-1alpha], HNF-4alpha, retinoid X receptor alpha [RXRalpha]:retinoic acid receptor alpha [RARalpha]) were studied via electrophoretic mobility shift analysis and nuclear Western blot analysis. Both methods of cytokine inactivation failed to maintain Ntcp protein or mRNA expression within 3 days after CBDL in either rats or mice (20%-40% of sham controls), while SHP mRNA expression increased three- to five-fold. Decreased nuclear HNF-1alpha and HNF-4alpha protein levels (45% and 60% of sham controls, respectively) and HNF-1alpha binding activity (32% of sham controls) were not restored during cytokine inactivation after CBDL, indicating cytokine-independent mechanisms of Ntcp regulation. RXRalpha:RARalpha binding remained unchanged in all experimental conditions. In conclusion, during obstructive cholestasis accumulating bile acids per se, without major contribution of cytokines, leads to downregulation of Ntcp via repression of HNF-1alpha and HNF-4alpha. PMID:15723437

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

2005-03-01

430

Rodent neurotoxicity bioassays for screening contaminated Great Lakes fish  

SciTech Connect

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

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

1996-03-01

431

NASA Rodent Foodbar: Long Term Effects in Swiss Webster Mice  

NASA Technical Reports Server (NTRS)

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

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

2001-01-01

432

Reprogramming the Cell Cycle for Endoreduplication in Rodent Trophoblast Cells  

PubMed Central

Differentiation of trophoblast giant cells in the rodent placenta is accompanied by exit from the mitotic cell cycle and onset of endoreduplication. Commitment to giant cell differentiation is under developmental control, involving down-regulation of Id1 and Id2, concomitant with up-regulation of the basic helix-loop-helix factor Hxt and acquisition of increased adhesiveness. Endoreduplication disrupts the alternation of DNA synthesis and mitosis that maintains euploid DNA content during proliferation. To determine how the mammalian endocycle is regulated, we examined the expression of the cyclins and cyclin-dependent kinases during the transition from replication to endoreduplication in the Rcho-1 rat choriocarcinoma cell line. We cultured these cells under conditions that gave relatively synchronous endoreduplication. This allowed us to study the events that occur during the transition from the mitotic cycle to the first endocycle. With giant cell differentiation, the cells switched cyclin D isoform expression from D3 to D1 and altered several checkpoint functions, acquiring a relative insensitivity to DNA-damaging agents and a coincident serum independence. The initiation of S phase during endocycles appeared to involve cycles of synthesis of cyclins E and A, and termination of S was associated with abrupt loss of cyclin A and E. Both cyclins were absent from gap phase cells, suggesting that their degradation may be necessary to allow reinitiation of the endocycle. The arrest of the mitotic cycle at the onset of endoreduplication was associated with a failure to assemble cyclin B/p34cdk1 complexes during the first endocycle. In subsequent endocycles, cyclin B expression was suppressed. Together these data suggest several points at which cell cycle regulation could be targeted to shift cells from a mitotic to an endoreduplicative cycle. PMID:9529378

MacAuley, Alasdair; Cross, James C.; Werb, Zena

1998-01-01

433

Buffering and plasticity in vital rates of oldfield rodents.  

PubMed

1. Under the hypothesis of environmental buffering, populations are expected to minimize the variance of the most influential vital rates; however, this may not be a universal principle. Species with a life span <1 year may be less likely to exhibit buffering because of temporal or seasonal variability in vital rate sensitivities. Further, plasticity in vital rates may be adaptive for species in a variable environment with reliable cues. 2. We tested for environmental buffering and plasticity in vital rates using stage-structured matrix models from long-term data sets in four species of grassland rodents. We used periodic matrices to estimate stochastic elasticity for each vital rate and then tested for correlations with a standardized coefficient of variation for each rate. 3. We calculated stochastic elasticities for individual months to test for an association between increased reproduction and the influence of reproduction, relative to survival, on the population growth rate. 4. All species showed some evidence of buffering. The elasticity of vital rates of Peromyscus leucopus (Rafinesque, 1818), Sigmodon hispidus Say & Ord, 1825 and Microtus ochrogaster (Wagner, 1842) was negatively related to vital rate CV. Elasticity and vital rate CV were negatively related in Peromyscus maniculatus (Wagner, 1845), but the relationship was not statistically significant. Peromyscus leucopus and M. ochrogaster showed plasticity in vital rates; reproduction was higher following months where elasticity for reproduction exceeded that of survival. 5. Our results suggest that buffering is common in species with fast life histories; however, some populations that exhibit buffering are capable of responding to short-term variability in environmental conditions through reproductive plasticity. PMID:22375923

Reed, Aaron W; Slade, Norman A

2012-09-01

434

Lung Function Measurements in Rodents in Safety Pharmacology Studies  

PubMed Central

The ICH guideline S7A requires safety pharmacology tests including measurements of pulmonary function. In the first step – as part of the “core battery” – lung function tests in conscious animals are requested. If potential adverse effects raise concern for human safety, these should be explored in a second step as a “follow-up study”. For these two stages of safety pharmacology testing, both non-invasive and invasive techniques are needed which should be as precise and reliable as possible. A short overview of typical in vivo measurement techniques is given, their advantages and disadvantages are discussed and out of these the non-invasive head-out body plethysmography and the invasive but repeatable body plethysmography in orotracheally intubated rodents are presented in detail. For validation purposes the changes in the respective parameters such as tidal midexpiratory flow (EF50) or lung resistance have been recorded in the same animals in typical bronchoconstriction models and compared. In addition, the technique of head-out body plethysmography has been shown to be useful to measure lung function in juvenile rats starting from day two of age. This allows safety pharmacology testing and toxicological studies in juvenile animals as a model for the young developing organism as requested by the regulatory authorities (e.g., EMEA Guideline 1/2008). It is concluded that both invasive and non-invasive pulmonary function tests are capable of detecting effects and alterations on the respiratory system with different selectivity and area of operation. The use of both techniques in a large number of studies in mice and rats in the last years have demonstrated that they provide useful and reliable information on pulmonary mechanics in safety pharmacology and toxicology testing, in investigations of respiratory disorders, and in pharmacological efficacy studies. PMID:22973226

Hoymann, Heinz Gerd

2012-01-01

435

Epidemiology of Bartonella infection in rodents and shrews in Taiwan.  

PubMed

During the period of August 2002 and November 2004, an epidemiological investigation for Bartonella infection was conducted in small mammals in Taiwan. Using whole blood culture on chocolate agar plates, Bartonella species were successfully isolated from 41.3% of the 310 animals tested. The isolation rate of Bartonella species varied among different animal species, including 52.7% of the 169 Rattus norvegicus, 28.6% of the 126 Sucus murinus, 10% of the 10 Rattus rattus and 66.7% of the three Rattus losea. Bacteremia prevalence also varied with the origin of the animals, as 56.2% of the animals captured on farms, 38.6% of the ones captured at harbour sites and 11.8% of the animals captured from urban areas were bacteremic. Through molecular analysis of the gltA gene and 16S/23S intergenic spacer region, genetic diversity of Bartonella organisms was identified, including strains closely related to Bartonella tribocorum, Bartonella grahamii, Bartonella elizabethae, Bartonella phoceensis and Bartonella rattimassiliensis. Moreover, this is the first report of zoonotic B. elizabethae and B. grahamii identified in R. losea, the lesser rice-field rat. Various Bartonella species were identified in R. norvegicus, compared to 97.2% of Suncus murinus with unique Bartonella species. By indirect immunofluorescence antibody test, using various rodent Bartonella species as antigens, consistently low percentage of seropositivity implied that small mammals may play a role as competent reservoirs of Bartonella species in Taiwan. Future studies need to be conducted to determine whether these Bartonella species would be responsible for human cases of unknown fever or febrile illness in Taiwan, especially zoonotic B. elizabethae and B. grahamii. PMID:19538457

Hsieh, J-W; Tung, K-C; Chen, W-C; Lin, J-W; Chien, L-J; Hsu, Y-M; Wang, H-C; Chomel, B B; Chang, C-C

2010-09-01

436

Stress induced obesity: lessons from rodent models of stress.  

PubMed

Stress was once defined as the non-specific result of the body to any demand or challenge to homeostasis. A more current view of stress is the behavioral and physiological responses generated in the face of, or in anticipation of, a perceived threat. The stress response involves activation of the sympathetic nervous system and recruitment of the hypothalamic-pituitary-adrenal (HPA) axis. When an organism encounters a stressor (social, physical, etc.), these endogenous stress systems are stimulated in order to generate a fight-or-flight response, and manage the stressful situation. As such, an organism is forced to liberate energy resources in attempt to meet the energetic demands posed by the stressor. A change in the energy homeostatic balance is thus required to exploit an appropriate resource and deliver useable energy to the target muscles and tissues involved in the stress response. Acutely, this change in energy homeostasis and the liberation of energy is considered advantageous, as it is required for the survival of the organism. However, when an organism is subjected to a prolonged stressor, as is the case during chronic stress, a continuous irregularity in energy homeostasis is considered detrimental and may lead to the development of metabolic disturbances such as cardiovascular disease, type II diabetes mellitus and obesity. This concept has been studied extensively using animal models, and the neurobiological underpinnings of stress induced metabolic disorders are beginning to surface. However, different animal models of stress continue to produce divergent metabolic phenotypes wherein some animals become anorexic and lose body mass while others increase food intake and body mass and become vulnerable to the development of metabolic disturbances. It remains unclear exactly what factors associated with stress models can be used to predict the metabolic outcome of the organism. This review will explore a variety of rodent stress models and discuss the elements that influence the metabolic outcome in order to further extend our understanding of stress-induced obesity. PMID:23898237

Patterson, Zachary R; Abizaid, Alfonso

2013-01-01

437

46 CFR 42.30-15 - Tropical Zone.  

Code of Federal Regulations, 2010 CFR

...Southern boundary of the Tropical Zone. The southern boundary of the Tropical Zone is the rhumb line from the Port of Santos, Brazil, to the point where the meridian of longitude 40° W. intersects the Tropic of Capricorn; thence the Tropic of...

2010-10-01

438

46 CFR 42.30-15 - Tropical Zone.  

Code of Federal Regulations, 2013 CFR

...Southern boundary of the Tropical Zone. The southern boundary of the Tropical Zone is the rhumb line from the Port of Santos, Brazil, to the point where the meridian of longitude 40° W. intersects the Tropic of Capricorn; thence the Tropic of...

2013-10-01

439

46 CFR 42.30-15 - Tropical Zone.  

Code of Federal Regulations, 2011 CFR

...Southern boundary of the Tropical Zone. The southern boundary of the Tropical Zone is the rhumb line from the Port of Santos, Brazil, to the point where the meridian of longitude 40° W. intersects the Tropic of Capricorn; thence the Tropic of...

2011-10-01

440

46 CFR 42.30-15 - Tropical Zone.  

Code of Federal Regulations, 2012 CFR

...Southern boundary of the Tropical Zone. The southern boundary of the Tropical Zone is the rhumb line from the Port of Santos, Brazil, to the point where the meridian of longitude 40° W. intersects the Tropic of Capricorn; thence the Tropic of...

2012-10-01

441

Occurrence of ectoparasitic arthropods associated with rodents in Hail region northern Saudi Arabia.  

PubMed

Ectoparasitic arthropods are a diverse element of the Saudi fauna. Due to this, a survey of ectoparasites associated with rodents was conducted as a preliminary study in five districts of Hail region of northern Saudi Arabia for the first time. Ectoparasites extracted from 750 rodents were sampled and identified by recording their frequency of appearance. Results revealed that 1,287 ectoparasites infested 316 of the captured rodent hosts. These ectoparasites parasitized on four species of rodents including three species of rats Rattus rattus rattus, Rattus rattus frugivorus, and Rattus rattus alexandrinus and one species of mouse Acomys dimidiatus (Rodentia: Muridae). The ectoparasites belong to four different groups: ticks, fleas, lice, and mites. Ticks were the highest in the number, while fleas were the lowest among all the extracted ectoparasite groups. The collected ectoparasitic arthropods consisted of seven species. Ticks were of two species: Rhipicephalus turanicus and Rhipicephalus sanguineus (Acari: Ixodidae), fleas were of two species: Xenopsylla cheopis and Xenopsyllus conformis mycerini (Siphonaptera: Pulicidae), lice was a single species: Polyplax serrata (Anoplura: Hoplopleuridae), and mites were of two species: Laelaps nuttali and Laelaps echidninus (Mesostigmata: Laelapidae). The findings of the study showed that the intensity of infestation was varied between rodent host sexes, wherein females had the highest rate of parasitic infestation, and the parasitic index of appearance was very high for one group of parasites (i.e., ticks). The parasitic prevalence was 42.13 % on rodents, and mites were the most prevalent parasite species. Overall, this study was carried out to establish baseline data for ectoparasite-infested rodents in Hail region, Saudi Arabia, and may help for appropriate planning to control zoonotic diseases in this area. PMID:24838257

Asiry, Khalid A; Fetoh, Badr El-Sabah A

2014-09-01

442

Neogene paleobiogeography and East African paleoenvironments: contributions from the Tugen Hills rodents and lagomorphs.  

PubMed

A minimum of 28 genera of rodents and one genus of lagomorph were recovered from the Tugen Hills, Baringo District, Kenya, from localities dating from over 15.5 to about 4.4 Ma. The middle Miocene (sites dated between 15.8 and 15.3 Ma) rodent fauna recovered primarily from the Kipsaramon site complex, Muruyur Formation, includes a mixture of characteristically early Miocene taxa, and more derived forms. Composition of the African rodent fauna changes dramatically with the introduction of myocricetodontines, democricetodontines, and dendromurines, immigrants primarily from southern Asia. In the Tugen Hills, these taxa are first found in the Kabasero localities, Ngorora Formation, at sites dating from 12.5-12.33 Ma. A second major change in the African rodent fauna reflects the introduction of murines, immigrants from southern Asia. In the Tugen Hills murines are first encountered at Kapcheberek, Lukeino Formation, dated to 5.9-5.7 Ma. One rodent genus from the Lukeino Formation (Arvicanthis), and two from the Tabarin locality, Chemeron Formation (Heliosciurus, Paraxerus; 4.5-4.4 Ma), represent the earliest records of these extant African genera. A cricetomyine from the Ngorora Formation (12.5 Ma) is likely the earliest report of this exclusively African group. One of the earliest African records of porcupines (Hystricide) is from the Lukeino Formation. Lagomorphs are poorly represented, but include one of the earliest African occurrences of the family Leporidae from the Mpesida Beds (bracketed by dates of 7-6.2 Ma), and possibly a new genus of leporid from the Kapcheberek locality. Analysis of the Tugen Hills small mammals in association with other African records suggests several episodes of dispersal between Africa and Eurasia during the middle and late Miocene. Rodents from Kipsaramon are indicative of forests in conjunction with more open habitats. Those from the Kapcheberek locality are suggestive of a savanna habitat. The rodents from the Tabarin locality suggest a woodland environment. PMID:11795976

Winkler, Alisa J

2002-01-01

443

Modeling susceptible infective recovered dynamics and plague persistence in California rodent-flea communities.  

PubMed

Plague persists as an enzootic in several very different rodent-flea communities around the world. In California, a diversity of rodent-flea communities maintains the disease, and a single-host reservoir seems unlikely. Logistic regression of plague presence on climate and topographic variables predicts plague in many localities where it is absent. Thus, a dynamic community-based analysis was needed. Deterministic Susceptible Infective Recovered (SIR) models were adapted for plague and analyzed with an eye for insights concerning disease persistence. An R simulation program, Plaguesirs, was developed incorporating multihost and multivector SIR dynamics, demographic and environmental stochasticity, density dependence, and seasonal variation in birth and death. Flea-rodent utilization matrices allowed us to get transmission rates as well as flea carrying capacities. Rodent densities allowed us to estimate host carrying capacities, while maximum birth rates were mainly approximated through an examination of litter phenology and demography. We ran a set of simulations to assess the role of community structure in maintaining plague in a simulated version of Chuchupate campground in Ventura County. Although the actual campground comprises 10 rodent and 19 flea species, we focused on a subset suspected to act as a reservoir community. This included the vole Microtus californicus, the deer mouse Peromyscus maniculatus, the Ceratophyllid fleas Aetheca wagneri and Malareus telchinum, and the Leptopsyllid flea Peromyscopsylla hesperomys. The dynamics of 21 subsets of this community were simulated for 20 years. Single-rodent communities showed much lower disease persistence than two-rodent communities. However, so long as Malareus was present, endemicity was enhanced; removal of the other two fleas slightly increased disease persistence. Two critical features improved disease persistence: (1) host breeding season heterogeneity and (2) host population augmentation (due to two similar host species instead of one). Voles are winter-spring breeders compared to the spring-summer deer mice. While host synchronicity may enhance epidemics, host asynchronicity favors endemics. PMID:20158333

Foley, Patrick; Foley, Janet

2010-01-01

444

Factors determining the abundance and distribution of rodents in a shrub-steppe ecosystem: the role of shrubs  

Microsoft Academic Search

This study addressed the relative importances of shrub “resources” on a rodent community in a sagebrush dominated shrub-steppe ecosystem in southwestern Wyoming. Direct effects of shrubs (i.e., providing rodents with “food and cover”) were assessed by removing shrubs from a 1.25 ha study plot and monitoring both rodent populations and their food resources. Shrub architecture and shrub-related food resources were

Robert R. Parmenter; James A. MacMahon

1983-01-01

445

Microphysical Characteristics of Tropical Clouds  

NASA Technical Reports Server (NTRS)

This report summarizes the analysis of data collected by the University of North Dakota Citation II measurement platform during three TRMM Field measurement campaigns. The Citation II made cloud measurements during TEFLUN B in Florida, the LBA program in Brazil, and KWAJEX in Kwajalein. The work performed can be divided into two parts. The first part consisted of reformatting the Citation data into a form more easily used to compare to the satellite information. The second part consisted of examination of the cloud data in order to characterize the properties of the tropical clouds. The reformatting of the Citation data was quite labor intensive and, due to the fact that the aircraft was involved in three of the field campaigns, it required a substantial number of person-hours to complete. Much of the analysis done on the second part was done in conjunction with the thesis work of Nicholas Anderson, then a graduate student at the University of North Dakota.

Grainger, Cedric A.; Anderson, Nicholas

2004-01-01

446

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