Inactivation of RNA Viruses by Gamma Irradiation: A Study on Mitigating Factors.

Effective inactivation of biosafety level 4 (BSL-4) pathogens is vital in order to study these agents safely. Gamma irradiation is a commonly used method for the inactivation of BSL-4 viruses, which among other advantages, facilitates the study of inactivated yet morphologically intact virions. The reported values for susceptibility of viruses to inactivation by gamma irradiation are sometimes inconsistent, likely due to differences in experimental protocols.

Prenatal protein malnutrition alters the proportion but not numbers of parvalbumin-immunoreactive interneurons in the hippocampus of the adult Sprague-Dawley rat.

Prenatal protein malnutrition alters the structure and function of the adult rat hippocampal formation. The current study examines the effect of prenatal protein malnutrition on numbers of parvalbumin-immunoreactive (PV-IR) GABAergic interneurons, which are important for perisomatic inhibition of hippocampal pyramidal neurons. Brain sections from prenatally protein malnourished and normally nourished rats were stained for parvalbumin and PV-IR neurons were quantified using stereology in the dentate gyrus, CA3/2 and CA1 subfields, and the subiculum for both cerebral hemispheres.

Aging increases retinal vascular lesions characteristic of early diabetic retinopathy.

The goal of this study was to determine whether aging induces retinal vascular lesions that are similar to those seen in diabetic retinopathy. Female rats were randomly divided into four groups; each group represented a time point and consisted of four non-diabetic rats and four diabetic rats. At time points of 3, 12, 18, or 22 months of age, retinas were isolated and subjected to retinal trypsin digestion (RTD) for isolation of retinal capillary networks.

MDMA pretreatment leads to mild chronic unpredictable stress-induced impairments in spatial learning.

3,4-Methylenedioxymethamphetamine (MDMA) is a drug of abuse worldwide and a selective serotonin (5-HT) neurotoxin. An important factor in the risk of drug abuse and relapse is stress. Although multiple parallels exist between MDMA abuse and stress, including effects on 5-HTergic neurotransmission, few studies have investigated the consequences of combined exposure to MDMA and chronic stress.

Influence of prenatal protein malnutrition on behavioral reactivity to stress in adult rats.

In Experiment 1, adult prenatally protein malnourished and well-nourished male and female rats were tested in an open field after having been subjected to a 15-day regimen of varied uncontrollable and inescapable mild stress (experimental group). Their responses were compared with rats that had not been subjected to the stress regimen (control group). In the control group, females with a history of prenatal malnutrition made significantly fewer entries into the center of the arena than did well-nourished females, suggesting that baseline differences in anxiety exist between the two nutritional groups of females.

Prenatal malnutrition alters diazepam-mediated suppression of ultrasonic vocalizations in an age dependent manner.

The sensitivity of prenatally malnourished rats to the ultrasonic vocalization (USV) suppressant effect of diazepam (a non-specific benzodiazepine (BZ) receptor agonist) was investigated. Male offspring of dams provided with a protein deficient diet (6% casein) for 5 weeks prior to mating and throughout pregnancy were compared to the offspring of mothers provided with a diet of adequate protein content (25% casein). At postnatal day 7 or 11, pups were injected with vehicle or one of five doses of DZ (0.

Asymmetry of neuron numbers in the hippocampal formation of prenatally malnourished and normally nourished rats: a stereological investigation.

There is considerable evidence for lateralization of hippocampal function and hemispheric asymmetry in humans. In the rat, studies have reported asymmetries in the thicknesses of layers, the volumes of hippocampal subfields, and the density of cells at specific points along the septotemporal axis. To determine if there is an asymmetry of neuron numbers and whether prenatal malnutrition affects any asymmetries, 90-day old male Sprague-Dawley rats that were either normally nourished or malnourished prenatally were perfused with 4% paraformaldehyde and the brains cut into 30-micro m sections.

Genome-wide scan for quantitative trait loci influencing spatial navigation and social recognition memory in Dahl rats.

The genetic determinants of learning and memory have been difficult to unravel because of the complex inheritance of these forms of cognitive behavior encompassing multiple genetic and environmental factors. Indeed, genes that can account for strain and individual variations in learning and memory are largely unknown. Here we report a genome-wide scan for quantitative trait loci (QTLs) affecting spatial learning and memory and social recognition memory in an F2 population derived from Dahl rats.

Prenatal malnutrition and sleep states in adult rats: effects of restraint stress.

Independently, prenatal malnutrition and psychological/physical stress have been shown to affect sleep architecture in adult rats. As malnutrition and stress commonly co-exist in malnourished human populations, the objective of the present study was to ascertain the combined effects of these two insults by examining sleep-wake parameters following a brief restraint stress in prenatally protein malnourished rats. The male offspring of rats provided with a protein deficient diet (6% casein) for 5 weeks prior to mating and throughout pregnancy were implanted with recording electrodes beginning at postnatal day 90.

Prenatal protein malnutrition induces a phase shift advance of the spontaneous locomotor rhythm and alters the rest/activity ratio in adult rats.

Evidence is accumulating for significant structural and functional changes within the central nervous system (CNS) following prenatal protein malnutrition. Included among the structures that are likely to be affected are the suprachiasmatic nuclei (SCN) involved in the regulation of locomotor activity, sleep-wake cycle, and drinking behavior. To determine the effects of prenatal protein malnutrition on the spontaneous activity rhythm, 24 h radiotelemetric measurements were recorded over an 8-day period.

Regulation of heat shock gene transcription in neuronal cells.

The heat shock protein (HSP) molecular chaperones are the primary cellular defense against damage to the proteome, initiating refolding of denatured proteins and regulating degradation after severe protein damage. Many neurodegenerative disorders involve aberrant protein folding and protein damage, which accumulates in an age-dependent manner. Ageing is associated with the decrease in activity of the heat shock transcription factors (HSF) that regulate HSP gene transcription.

Prenatal protein malnutrition in rats alters the c-Fos response of neurons in the anterior cingulate and medial prefrontal region to behavioral stress.

Prenatal protein malnutrition affects brain development and behavior despite dietary rehabilitation from birth. Behavioral alterations include abnormal responses to stressors. To explore what brain regions mediate this altered response, we used immunocytochemistry to c-Fos protein, a transcription factor marking neuronal activation.

Effect of prenatal protein malnutrition on numbers of neurons in the principal cell layers of the adult rat hippocampal formation.

Malnutrition has been associated with a variety of functional and anatomical impairments of the hippocampal formation. One of the more striking of these is widespread loss of hippocampal neurons in postnatally malnourished rats. In the present study we have investigated the effect of prenatal malnutrition on these same neuronal populations, neurons that are all generated during the period of the dietary restriction.

Effects of prenatal protein malnutrition and acute postnatal stress on granule cell genesis in the fascia dentata of neonatal and juvenile rats.

Although postnatal genesis of granule cells in the hippocampal fascia dentata is known to be influenced by prenatal protein deprivation or by stress, the combined effects of prenatal protein malnutrition and stress on these cells are unknown. This study was designed to examine this combined effect. Well-nourished and prenatally malnourished pups on postnatal day 7 (P7) were stressed by maternal separation and reduction of body temperature and on postnatal day 30 (P30) by immobilization with restraint.

Modulation of learning and memory in Dahl rats by dietary salt restriction.

The Dahl rat represents a robust animal model of salt-sensitive hypertension, with Dahl S rats being salt sensitive and Dahl R rats (the Dahl S counterparts) being salt resistant for the development of hypertension. Here we evaluate the effect of reduced dietary salt intake on learning and memory in the Dahl rat model. Salt restriction produced a significant impairment in social transmission of food preference and social recognition memory in Dahl S rats without affecting spatial learning.

Spatial learning deficits induced by muscimol and CL218,872: lack of effect of prenatal malnutrition.

The sensitivity of prenatal protein malnourished rats to the amnestic properties of the direct GABAA receptor agonist muscimol and the selective benzodiazepine (BZ) receptor agonist, CL218,872, was studied in the male offspring of rats provided with a protein deficient diet (6% casein) for 5 weeks prior to mating and throughout pregnancy. At postnatal day 90, rats were tested during acquisition of the submerged platform version of the Morris water maze task using four systemic doses of muscimol (0.1, 0.

X-linked loci influence spatial navigation performance in Dahl rats.

Elucidation of natural genetic variations underlying strain or individual differences in cognitive function has remained elusive. Here we report the identification of two genetic loci that influence spatial navigation in Dahl rats. In the Morris water maze test, Dahl R rats exhibited efficient spatial navigation, whereas Dahl S rats displayed poor spatial navigation (accuracy).

Ultrasonic call characteristics of rat pups are altered following prenatal malnutrition.

The male offspring of rats provided with a protein deficient diet (6% casein) for 5 weeks prior to mating and throughout pregnancy were subjected to a brief period of isolation and cooling at postnatal Days (P)7, 9, and 11, and their ultrasonic vocalizations were compared with those of well-nourished pups. Calls were categorized into 12 different types based upon their sonographic patterns. Although call rates were equal, the call characteristics of the prenatally malnourished pups differed significantly from those of well-nourished controls.

Prenatal protein malnutrition enhances stimulus control by CDP, but not a CDP/THIP combination in rats.

In the present study, the effects of prenatal protein malnutrition on stimulus control exerted by the benzodiazepine (BZ), chlordiazepoxide (CDP) and the GABA-A receptor agonist 4,5,6,7-tetrahydroisoxazolo[5,4-c]pyridin-3-ol (THIP) were characterized. The adult, male offspring of female Sprague-Dawley rats fed either low (6% casein) or adequate (25% casein) protein diets 5 weeks prior to mating and throughout pregnancy served as subjects. Subjects were first trained to discriminate CDP (8.

Prenatally protein-malnourished rats are less sensitive to the amnestic effects of medial septal infusions of chlordiazepoxide.

Evidence is mounting that prenatal protein malnutrition affects the physiological properties of the GABAergic neurotransmitter system in rats. To investigate the functional behavioral consequences of these changes, chlordiazepoxide (CDP, a positive modulator of the GABA(A) receptor) was applied directly to the medial septum and the amnestic response appraised. In adulthood, male offspring of rats provided with a protein-deficient diet (6% casein) for 5 weeks prior to mating and throughout pregnancy underwent stereotaxic surgery to implant steel cannulae aimed at the medial septum.

Prenatal protein restriction increases sensitization to cocaine-induced stereotypy.

The present study characterized the total amount of stereotyped behavior following acute and repeated administration of cocaine in male and female prenatally protein malnourished rats. Adult offspring of female Sprague-Dawley rats fed either a low (6% casein) or adequate (25% casein) protein diet 5 weeks prior to mating and throughout their pregnancy were studied. Once every 3 days (for a total of six injections), half the rats from each nutritional treatment group (repeated exposure) were injected with cocaine (30 mg/kg, i.

Chlordiazepoxide-induced spatial learning deficits: dose-dependent differences following prenatal malnutrition.

The sensitivity of prenatally protein-malnourished rats to the amnestic properties of the benzodiazepine (BZ) receptor agonist, chlordiazepoxide (CDP), was studied in the male offspring of rats provided with a protein-deficient diet (6% casein) for 5 weeks prior to mating and throughout pregnancy. Rats were tested during acquisition of the submerged platform version of the Morris water maze task using three systemic doses of CDP (3.2, 5.

Differential Effects of Prenatal Protein Malnutrition and Prenatal Cocaine on Radial Arm Maze Performance in Adult Male Rats.

The effects of prenatal cocaine and protein malnutrition were examined on acquisition of the radial arm maze in adult male Sprague-Dawley rats whose mothers were provided with a 6% casein, a 25% casein or a standard chow diet and cocaine (30mg/kg) or saline injections beginning 5 weeks prior to mating and continuing to parturition. Rats were tested using an 8-arm radial maze with 4 baited arms and were required to collect all 4 food pellets within 5 min to complete a trial. Subjects were tested for 1 trial/day until they met criterion for successful acquisition of the task.

Prenatally malnourished female but not male rats show increased sensitivity to MK-801 in a differential reinforcement of low rates task.

A reduced behavioral sensitivity to drugs acting on central GABAergic, serotonergic, opioid and cholinergic systems has previously been identified in predominantly male malnourished animals. The present study sought to compare the effects of the non-competitive N-methyl-D-aspartate (NMDA) receptor antagonist MK-801 on responding maintained by a differential reinforcement of low rates (DRL-18s) operant schedule in two groups of rats with different prenatal nutritional histories (well-nourished and protein restricted). The schedule required that the rats space their responses at least 18 s apart in order to obtain food reinforcement (timing behavior).