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PubMed2000

Genetic control of acute ethanol-induced behaviors in Drosophila.

BACKGROUND: In most organisms in which acute ethanol exposure has been studied, it leads to similar changes in behavior. Generally, low ethanol doses activate the central nervous system, whereas high doses are sedative. Sensitivity to the acute intoxicating effects of ethanol is in part under genetic control in rodents and humans, and reduced sensitivity in humans predicts the development of alcoholism (Crabbe et al., 1994; Schuckit, 1994). We have established Drosophila melanogaster as a model organism to study the mechanisms that regulate acute sensitivity to ethanol. METHODS: We measured the effects of ethanol vapor on Drosophila locomotor behaviors by using three different assays. Horizontal locomotion was quantified in a locomotor chamber, turning behavior was assayed in narrow tubes, and ethanol-induced loss of postural control was measured in an inebriometer. Mutants with altered sensitivity to the acute effects of ethanol were generated by treatment with ethyl methane sulfonate and isolated by selection in the inebriometer. We ascertained the effects of these mutations on ethanol pharmacokinetics by measuring ethanol levels in extracts of flies at various times during and after ethanol exposure. RESULTS: Among nearly 30,000 potentially mutant flies tested, we isolated 19 mutant strains with reduced and 4 strains with increased sensitivity to the acute effects of ethanol as measured in the inebriometer. Of these mutants, four showed changes in ethanol absorption. Two mutants, named barfly and tipsy to reflect their reduced and increased ethanol sensitivity in the inebriometer, respectively, were analyzed for locomotor behaviors. Both mutants exhibited ethanol-induced hyperactivity that was indistinguishable from wild type. However, barfly and tipsy displayed reduced and increased sensitivity to the sedative effects of ethanol, respectively. Finally, both mutants showed an increased rate of ethanol-induced turning behavior. CONCLUSIONS: The effects of acute ethanol exposure on Drosophila locomotor behaviors are remarkably similar to those described for mammals. The analysis of mutants with altered sensitivity to ethanol revealed that the genetic pathways which regulate these responses are complex and that single genes can affect hyperactivity, turning, and sedation independently.

Absorption↗

PubMed1988

Experimental approaches to colon cancer prevention in humans.

Colorectal cancer is a major illness in the Western world. International and migrant studies suggest that environmental causes, notably a fat- and calorie-dense diet (even if adopted in adulthood), are associated with the disease. Case-control studies have not conclusively identified specific etiologic dietary factors, however. In addition, the emphasis placed on migrant studies has led many to overlook potentially important genetic factors that might help to explain some of the discrepancies in the epidemiologic data. Thus, the cause(s) of colorectal cancer remain unclear and hence effective preventive strategies are not presently available. Numerous tenable hypotheses have been generated as a consequence of observational and analytical epidemiologic studies, as well as rodent experiments. Controlled trials to test these hypotheses using colorectal cancer as an endpoint are not justifiable at present. It is possible, however, that "intermediate markers" (such as epithelial cell proliferation rates and others) that are associated with colorectal cancer in both humans and experimental animal systems might provide the means for hypothesis testing in short-term clinical trials. Despite the fact that this approach has several caveats, consistent results obtained in short-term studies would more readily justify the undertaking of a large-scale, long-term controlled study using colon cancer or adenomatous polyp recurrence as an endpoint.

Colorectal Neoplasms↗

PubMed2004

Control of immature Ixodes scapularis (Acari: Ixodidae) on rodent reservoirs of Borrelia burgdorferi in a residential community of southeastern Connecticut.

A 3-yr community-based study was conducted on residential properties on Mason's Island, Mystic, CT, to determine the efficacy of a rodent-targeted acaricide (fipronil) to control immature Ixodes scapularis (Say) on Peromyscus leucopus. Results indicated that modified commercial bait boxes were effective as an acaricide delivery method for reducing nymphal and larval tick infestations on white-footed mice by 68 and 84%, respectively. Passive application of fipronil significantly reduced the infection rate of Borrelia burgdorferi among white-footed mice by 53%. Moreover, the abundance of questing I. scapularis adults on treated properties was reduced by 77% and fewer were infected with spirochetes (31%) compared with untreated sites (47%) after 3 yr of treatment. Likewise, the abundance of host-seeking nymphs was significantly reduced on treated properties by >50%. Finally, infection rates in flagged nymphal ticks for both B. burgdorferi and Anaplasma phagocytophilum were reduced by 67 and 64%, respectively, after only 2 yr of treatment. Results from this 3-yr trial indicate that the use of fipronil passively applied to reservoir animals by bait boxes is an environmentally acceptable means to control ticks, interrupt the natural disease transmission cycle, and reduce the risk of Lyme disease for residents of treated properties.

Animals↗

PubMedDate not supplied

[Effect of deficiency of dietary nitrogen on cellulose digestibility and nitrogen-fixing flora activity in the sibling vole Microtus rossiaemeridionalis].

The effect of food composition on nitrogen-fixing activity of the symbionts living in the digestive tract of the sibling vole Microtus rossiaemeridionalis was experimentally studied. In the control, the rodents were allowed to select any of three food mixes: protein-rich, protein-free with low cellulose content, and protein-free with high cellulose content. The voles consumed the food in a proportion corresponding to 16% of protein and about 6% of cellulose. Exclusion of the protein-rich food considerably increased cellulose consumption (up to 12%) and digestibility (from 35 to 64%). The changes in the consumed food composition were reflected in localization of nitrogenase activity in the digestive tract: the control level of nitrogen-fixing activity in the cecum was three times that in the proventriculus, while an inverse proportion was observed in the experimental groups. In all cases, the colon was the major locus of nitrogen fixation.

Animals↗

PubMed2005

Capsicum oleoresin: development of an in-soil repellent for pocket gophers.

A pre- and post-monitoring study was conducted of the potential use of capsicum oleoresin as an in-soil repellent for northern pocket gophers (Thomomys talpoides). Pocket gophers were captured in irrigated alfalfa (Medicago sativa L), affixed with radio transmitters, and monitored daily for location. Six plots (4.87 x 4.87 m) each were randomly assigned to capsicum oleoresin and soybean oil treatments; these were set up based upon the centers of initial core areas of gophers. Mean (+/-SD) volumes of capsicum oleoresin and water and soybean oil and water mixtures (10 + 90 by volume) dispensed onto plots equaled 178.5 (+/-4.7) and 175.7 (+/-14.0) liters, respectively. Movements (m) of the radio-transmitted gophers from plot centers were computed for four daily readings (i.e., 0801-1000, 1101-1300, 1501-1700 and 1801-2000 h). Spectrophotometric analysis of soil samples from capsicum oleoresin plots validated the presence of capsicum on plots and the absence of capsicum on placebo- and off-plot locations. Analysis of variance for movement distances of gophers yielded a Date main effect [F(11, 103) = 2.08, P < or = 0.03] and a Date x Reading (time) interaction [F(32, 299) = 3.21, P < or = 0.01]. Results showed that gophers were located farther from plot centers for the 0801-1000 and 1501-1700 h telemetry readings for < or =3 days post-chemical application-a probable 'disturbance' effect rather than a chemical-induced avoidance. In a prior laboratory study, capsicum oleoresin and soil treatments of 1.5% w/w capsicum caused nearly a 50% decrease in soil contact time by gophers relative to placebo-exposed control animals. This implies that procedural variables warrant revision before abandoning this approach. The potential for soil insertion of repellents as a technique for expelling pocket gophers from territories and some methodological changes for future research of the technique are discussed.

Animals↗

PubMed1980

Laboratory and field evaluation of pyriminyl as a poison for Rattus norvegicus.

Laboratory tests indicated that the optimum concentration for pyriminyl in rat baits was between 1% and 3%. In field trials in which 0.5% pyriminyl (the concentration in commercial use) was compared with 2.5% zinc phosphide for the control of rats on farms, the pyriminyl treatments were significantly less effective than the zinc phosphide even when the poisoned baits were left down for 7 days instead of 1 day after prebaiting. Both poisons were as effective in medium oatmeal bait as they were in medium oatmeal containing 5% corn oil and 5% sugar.

Animals↗

PubMed1974

Field trials of calciferol against warfarin resistant infestations of the Norway rat (Rattus norvegicus Berk).

The effectiveness of calciferol (vitamin D(2)) against Rattus norvegicus was investigated in field trials on twenty-three farms with rat infestations partly resistant to warfarin. At 0.01% combined with warfarin at 0.025% no rodenticidal effect of the calciferol was discernible. At 0.025% with warfarin at the same concentration, results were better, but not appreciably better than is often obtained with warfarin alone against resistant rat populations. When the concentration of calciferol was stepped up to 0.1%, four out of five treatments in which the poison was applied directly gave complete control. The fifth may have partly failed because of poison shyness caused by under-baiting. Five out of six more treatments done after ;pre-baiting' were also successful. The sixth failed for reasons unconnected with the choice of poison.Six further infestations that were not responding adequately to warfarin treatments were quickly controlled when, in three instances, calciferol at 0.1% was used instead and, in three more, it was used together with warfarin. It is concluded that calciferol at 0.1% is an effective poison against R. norvegicus either combined with warfarin or not, but that because at 0.1% its effect is subacute rather than chronic, there may be a case in some environments for using it only after pre-baiting.

Animals↗

PubMed1990

[Cereal grain preference of rats].

Cereal grains are usually used as the main material for preparing rodenticide baits. However, the preferences for different grains varies according to species and habitats of rats, and locations. A formula accepted at one location may not be suitable in other places, where rats are accustomed to different types of food. It is therefore important to understand the feeding habits of local rat species before implementing a control program. Seven kinds of grains, including hulled rice, corn, barley, wheat, sorghum, pranuts, and sweet potatoes were tested to study the preferences of rats in the laboratory. The results revealed that Bandicota nemorivaga, Rattus losea and R. norvegicus prefer hulled rice; Apodemus agrarius and Mus musculus prefer peanuts, and R. rattus prefers corn. The influence of quality and nutrient contents of baits on the consumption of the rats is also discussed.

Animals↗

PubMed2002

Posttranscriptional regulation of p18 and p27 Cdk inhibitor proteins and the timing of oligodendrocyte differentiation.

A cell-intrinsic timer helps control when rodent oligodendrocyte precursor cells (OPCs) exit the cell cycle and terminally differentiate when cultured in platelet-derived growth factor (PDGF) and thyroid hormone (TH). There is evidence that the cyclin-dependent kinase inhibitor (CKI) p27/Kip1 (p27) is a component of this TH-regulated timer, as it increases as OPCs proliferate and is required for the timer to operate accurately. Here, we provide evidence that another CKI, p18/INK (p18), may also be a component of the timer: it increases as OPCs proliferate, and its overexpression in OPCs accelerates the timer, causing the cells to differentiate prematurely. We also show that the overexpression of p27 accelerates the timer and that the increases in both p27 and p18 that occur in proliferating OPCs are controlled posttranscriptionally. By contrast, we show that the overexpression of either p18 or p27 in OPCs proliferating in PDGF and the absence of TH greatly slows the cell cycle but fails to accelerate the spontaneous differentiation that normally occurs independently of TH.

Animals↗

PubMed1980

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

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.

Animals↗

PubMed1997

Quantitative analysis of the age-related fragmentation of hamster 24-h activity rhythms.

The continuous monitoring of spontaneous locomotor activity has emerged as one of the most widely used metrics in rodent circadian research. This behavioral measure is also extremely useful for the description of the effects of aging on circadian rhythms. The present study describes the successful use of a log-survivorship approach to identify discrete bouts of hamster wheel-running activity and provides a detailed description of the age-related fragmentation in the 24-h profile of this behavioral variable. In addition, stepwise discriminant analysis identified the most important quantitative measures for distinguishing between the individual patterns of wheel-running activity of young (3 mo) and old (17-18 mo) golden hamsters. The results suggest that this method of bout analysis can be a valuable tool for the study of genetic, developmental, neurochemical, physiological, and environmental factors involved in the temporal control of rodent locomotor behavior.

Aging↗

PubMed1976

Treatment of monocrotophos-poisoned birds of prey with pralidoxime iodide.

Monocrotophos, and organophosphorus insecticide, was sprayed by farmers to control a plague of levant voles in alfalfa fields. Large numbers of birds of prey attracted by the dying and dead voles developed secondary poisoning after eating the voles. Paralysis of skeletal muscles was the principal clinical finding in these birds. Many of the birds died but some were treated with pralidoxime iodide, 100 mg/kg of body weight, given by intramuscular injection. All treated birds recovered, some in a very short time.

Animals↗

PubMed1986

Relationship between autonomic and behavioral thermoregulation in the golden hamster.

Preferred ambient temperature (Ta) of male golden hamsters (Mesocricetus auratus) was measured repeatedly by placing the animals in a temperature gradient for 80 min. A total of 180 observations were made during the last 20 min of treatment in the gradient. The mean preferred Ta was 28.2 +/- 0.2 degrees C. In another experiment the same animals were placed in a temperature-controlled chamber for 80 min while metabolic rate, evaporative water loss, thermal conductance, and colonic temperature were measured at Ta's of 14-34 degrees C. The lower critical Ta, the Ta below which metabolic rate increased above the resting level, was 28 degrees C. This Ta corresponds closely to the mean preferred Ta of the hamster when placed in the temperature gradient. Evaporative water loss was minimal at Ta's of 14 and 16 degrees C and increased gradually with increasing Ta. Thermal conductance was minimal between Ta's of 14 and 28 degrees C and then increased sharply with increasing Ta. The data from the hamster are qualitatively similar to the mouse in that the preferred Ta corresponds with the lower critical Ta. It appears that, for these rodents, the control of preferred Ta is critically related to the animal's metabolic requirements.

Animals↗

PubMed1981

Trials of the anticoagulant rodenticides bromadiolone and difenacoum against the house mouse (Mus musculus L.).

Laboratory and field trials were conducted to determine the efficacy of the anticoagulant rodenticide bromadiolone against the house mouse (Mus musculus). In laboratory feeding tests, family groups of warfarin-resistant mice maintained in pens and conditioned to feeding on plain foods were offered pinhead oatmeal bait containing bromadiolone at 0.005%. Overall mortality in replicated 21-day poison treatments was 55/58 or 94.8%. Six field trials were carried out, using the same poison bait, against mice infesting farm buildings. Treatment success, estimated from the results of census baitings conducted before and after treatment, ranged between 60.4% and 100%, mean 92.4%. In equivalent field trials using difenacoum, another newly developed anticoagulant rodenticide, the control achieved ranged between 70.2% and 100%, mean 96.0%. Five field trials, three involving bromadiolone and two difenacoum, were not completely successful and the surviving mice were removed for laboratory examination. In 21-day toxicity tests, each animal was fed the poison bait offered to it earlier in the field. Bromadiolone and difenacoum gave kills of 12/21 (57.1%) and 9/11 (81.8%) respectively. The possible emergence of mouse populations resistant to these anticoagulants is considered.

4-Hydroxycoumarins↗

PubMed2005

A model of controlled acute hyperglycemia in rats: Effects of insulin and glucagon-like peptide-1 analog.

A rodent model of controlled acute hyperglycemia that is sensitive to glucose-lowering agents insulin and glucagon-like peptide-1 (GLP-1) analog has been developed. The studies show that anesthesia could be induced in fasted rats with ketamine (100 mg/kg) plus a low dose of xylazine (5 mg/kg) without inducing the acute hyperglycemia typically associated with these agents. Under these conditions, continuous infusion of glucose (10 and 20%) via the jugular vein for 30 to 150 min induced hyperglycemia in a time-dependent fashion. Administration of "loading" boluses of glucose (0.2-0.6 ml of a 20% solution) prior to continuous infusion of 10% glucose produced more immediate and sustained hyperglycemia. Plasma levels of a variety of glucoregulatory and stress hormones such as insulin, growth hormone, glucagon, and corticosterone were determined. Only glucagon levels changed significantly during induction and maintenance of hyperglycemia. The infusion of insulin (0.1 U/kg/h) or GLP-1 analog (10 microg/kg/h) effectively lowered blood glucose from its elevated levels. Insulin produced a significant increase in glucagon levels, and GLP-1 analog produced a significant increase in insulin levels without any change in other glucoregulatory and stress hormone levels. In conclusion, the present studies identified a novel approach for the induction of anesthesia and surgical manipulations without inducing hyperglycemia and further defined an approach for producing acute hyperglycemia in a controlled fashion in rodents. This model will be beneficial to study the influence of hyperglycemia in acute models of critical illness where hyperglycemia develops following the precipitating event. This model was responsive to insulin and GLP-1 analog, both of which were effective in ameliorating hyperglycemia.

Acute Disease↗

PubMedDate not supplied

Kidney mass and relative medullary thickness of rodents in relation to habitat, body size, and phylogeny.

We tested the hypotheses that relative medullary thickness (RMT) and kidney mass are positively related to habitat aridity in rodents, after controlling for correlations with body mass. Body mass, mass-corrected kidney mass, mass-corrected RMT, mass-corrected maximum urine concentration, and habitat (scored on a semiquantitative scale of 1-4 to indicate increasing aridity) all showed statistically significant phylogenetic signal. Body mass varied significantly among habitats, with the main difference being that aquatic species are larger than those from other habitats. Mass-corrected RMT and urine concentration showed a significant positive correlation (N=38; conventional r=0.649, phylogenetically independent contrasts [IC] r=0.685), thus validating RMT as a comparative index of urine concentrating ability. RMT scaled with body mass to an exponent significantly less than 0 (N=141 species; conventional allometric slope=-0.145 [95% confidence interval (CI)=-0.172, -0.117], IC allometric slope=-0.132 [95% CI=-0.180, -0.083]). Kidney mass scaled to an exponent significantly less than unity (N=104 species; conventional slope=0.809 [95% CI=0.751, 0.868], IC slope=0.773 [95% CI=0.676, 0.871]). Both conventional and phylogenetic analysis indicated that RMT varied among habitats, with rodents from arid areas having the largest values of RMT. A phylogenetic analysis indicated that mass-corrected kidney mass was positively related to habitat aridity.

Animals↗

PubMed1974

Some properties of calciferol as a rodenticide.

The potentiality of calciferol (alone and combined with warfarin) for the control of commensal rats and mice has been examined in the laboratory. Nearly all animals fed on 0.1% calciferol for 2 days died. Though illness usually reduced food intake after the first 24 hr. there was no sign of aversion to the poison at 0.1% - which is considered to be the lowest concentration suitable for use against Rattus norvegicus, R. rattus and Mus musculus in the field. There was some indication that resistance to warfarin in R. norvegicus may be correlated with susceptibility to calciferol. Toxicity tests with calciferol combined with warfarin indicated an additive effect between the compounds. No evidence for synergism was found however, although elsewhere there is some evidence for this.

Animals↗

PubMed2000

[A study on the epidemiology and preventive measure on epidemic haemorrhage fever in army barrack area in Shandong].

OBJECTIVE: In order to guide the army and civilians to carry out the prevention on epidemic haemorrhage fever (EHF), it's necessary to elucidate the epidemic feature of natural epidemic foci and the risk factors of EHF in the army - stationed areas. METHODS: Samples were tested by pathogenic and serologic means before data was collected and analyzed by case - control or family - control studies. RESULTS: Cases belong to house - mouse type (91.48%), field - mouse type (7.21%) and unclassified (1.31%) coexist in the stationed area. In the two types of noticed cases, no significant difference in distributions of sex, profession and ages. Most house - mouse type cases occurred in the peak time from March to June and field - mouse type in November to next February. The type of EHF virus antigen of mice and the type of serum were both accordant with their host types. Dwelling in border area, living rooms with mice, dogs raising, injury of mouth tissue, eating food contaminated by mice, and household with mice living around were more frequently seen in cases themselves and in families of the cases than in controls of both groups (P < 0.05). The mice intensity could be under control to 1.0%, if comprehensive measure on mice control can be implemented. CONCLUSIONS: The stationed area is an epidemic area mixed with both house - mouse and field - mouse types, with majority of house - mouse type. It was house - mouse type virus infection that caused the epidemic area expanded and the number of cases increased radically these years. EHF was epidemic in spring and summer season in the stationed area mainly because the infections were among family members. Food contaminated by mice or close contact with mice played an important role. Mice eradication and prevention were the leading measures to prevent EHF, from our more than ten years of experiences.

Adult↗