Sendai virus infection of mice with protein malnutrition.

Sendai virus pneumonia was produced in BALB/c mice fed protein-deficient diets in an effort to understand the severity of viral pneumonia in infants in developing countries. Animals on the deficient diet became clinically malnourished, and some aspects of cellular immunity were altered. In protein-deprived animals, the 50% lethal dose of intranasally administered Sendai virus was over 1,000-fold lower, pulmonary virus titers were higher, the infection was prolonged, and lung infection was established at a lower inoculum than in normal animals.     

Effects of acute and repeated exposure to stress on the hypothalamo-pituitary-adrenocortical activity in mice during postnatal development

Hypothalamo-pituitary-adrenocortical (HPA) response to a mild stressful procedure was investigated in mice at Days 8, 10, 12, and 14 of postnatal development. Pups that were removed from the dam and exposed to a novel odor (clean bedding) for 15 min showed higher plasma corticosterone levels than pups whose mother was removed from the cage for 15 min or unhandled pups at all ages, although statistically significant differences were only evident at Days 12 and 14. Lower HPA axis responding in younger mice was not due to immaturity since 8-day-old mice showed a significant and larger increase of plasma corticosterone levels when separated from the mother and isolated from littermates in the absence of bedding. Mice daily exposed to clean bedding (15 min) for the first 13 days of life did not show reduced plasma corticosterone response when reexposed to the stressor at 14 days of age. Conversely, increased plasma corticosterone levels in dams in response to removal of pups was not detectable after repeated exposure to this manipulation (14 days) regardless of the procedure their pups were submitted to, thus ruling out a role of maternal corticosterone passing through the milk on which the pups were fed. These results demonstrate that 15 min exposure to clean bedding is a noninvasive procedure able to elicit HPA axis response in developing mice over a wide age range without producing habituation.     

The relative importance of prenatal and postnatal maternal influences on growth in mice

Summary The cross-nursing technique was used to assess the relative importance of prenatal and postnatal maternal influences on growth in mice from an unselected population originated from a cross of four highly inbred strains. Body weights were studied at birth, 7-, 14-, 21- and 42-days, in addition to the weight gains between these ages and tail length at 21 and 42 days of age. At littering, each dam in each nursing set retained two of her own offspring and two were transfereed to each of the other dams in the set, so that each nursed litter contained six young representing three mothers. Prenatal influences accounted for 37, 15, 10, 11 and 13 % of the total variation in the respective body weights, while postnatal influences accounted for 0, 64, 65, 49 and 14% at the respective ages. In the case of weight gains, prenatal influences were responsible for 16, 4, 6 and 30%, while postnatal influences were responsible for 66, 66, 31 and 7% of the total variation in gain during the respective four periods examined. Apparently the individual weight gain from 7 to 14 days was a better measure of the lactational performance of the dam than individual 14-day weight. For tail length, prenatal influences accounted for 6 % and 4 % of the total variation in tail length at 21 and 42 days, respectively, while postnatal influences accounted for 60 % and 24 % at the respective ages. Generally, there was no indication of an important interaction between the nurse and the nursed young at any stage studied.     

Parasitological characteristics of Schistosoma mansoni infection in swiss mice with underlying malnutrition

The effects of a protein-restricted diet (8% protein, 81% carbohydrate and 11% lipids) on Schistosoma mansoni infectivity, fecal egg excretion and intestinal egg distribution in Swiss (SW) mice were studied. Pregnant mice received a deficient diet from the middle of gestation until delivery. Seven-days-old mice were exposed to 50 cercariae (BH strain, Brazil). Offspring mice had a free access to the deficient diet since lactation until adulthood. The controls were fed with a commercial mice diet. A parasitological examination was performed between six and eight weeks post-infection while both groups were necropsied one week later. Mice on the experimental diet showed a significant loss in body weight. There was no significant difference (p > 0.05) in pre-patent period, kinetics of egg excretion and worm recovery from mice on either diet. Significant differences (p < 0.05) were found concerning to the percentage of deposited eggs in the distal segment of the small intestine from hosts on the experimental diet. Our data suggest that experimental malnutrition induced for a long term has no detrimental effect on the acute schistosomiais infection in SW mice.     

The postnatal maternal environment affects autoimmune disease susceptibility in A/J mice

The postnatal maternal environment is known to increase susceptibility to a number of autoimmune diseases. Here we asked whether the postnatal maternal environment could influence autoimmune disease development to day 3 thymectomy (d3tx)-induced autoimmune ovarian disease (AOD) and experimental allergic encephalomyelitis (EAE) in cross-fostered A/J and B6 mice. A/J pups foster-nursed by B6 mothers exhibit an increase in autoimmune disease development while cross-fostering B6 pups on A/J mothers did not alter their susceptibility. The increase in AOD incidence seen in foster-nursed d3tx A/J mice correlated with a decrease in the total number of CD4⁺ T cells in the lymph nodes of these animals. Analysis of the cellular composition in the milk revealed that B6 mice shed significantly more maternally derived lymphocytes into their milk compared to A/J mothers. These data suggest that there are maternally derived postnatal factors that influence the development of autoimmune disease in A/J mice.     

Hypothermia after chronic mild stress exposure in rats with a history of postnatal maternal separations

The circadian system develops and changes in a gradual and programmed process over the lifespan. Early in life, maternal care represents an important zeitgeber and thus contributes to the development of circadian rhythmicity. Exposure to early life stress may affect circadian processes and induce a latent circadian disturbance evident after exposure to later life stress. Disturbance of the normal regulation of circadian rhythmicity is surmised to be an etiological factor in depression. We used postnatal maternal separation in rats to investigate how the early life environment might modify the circadian response to later life unpredictable and chronic stress. During postnatal days 2–14, male Wistar rats (n?=?8 per group) were daily separated from their mothers for a period of either 180?min (long maternal separation; LMS) or 10?min (brief maternal separation; BMS). In adulthood, rats were exposed to chronic mild stress (CMS) for 4 weeks. Body temperature, locomotor activity and heart rate were measured and compared before and after CMS exposure. LMS offspring showed a delayed body temperature acrophase compared to BMS offspring. Otherwise, adult LMS and BMS offspring demonstrated similar diurnal rhythms of body temperature, locomotor activity and heart rate. Exposure to CMS provoked a stronger and longer lasting hypothermia in LMS rats than in BMS rats. The thermoregulatory response appears to be moderated by maternal care following reunion, an observation made in the LMS group only. The results show that early life stress (LMS) in an early developmental stage induced a thermoregulatory disturbance evident upon exposure to unpredictable adult life stressors.     

The role of maternal antibody in contact infection of mice with Sendai virus.

To study the role of maternal antibody in infection with Sendai virus in mice, maternally immune and non-immune mice, aged 4 to 5 weeks, were placed in cages with infector mice and the cages were kept for 19 days in a vinyl isolator. Neither increase of hemagglutination inhibiting antibody titers nor gross pulmonary lesions was recognized on the immune mice during the observation period in contrast with the non-immune mice. However, the multiplication of the virus in their respiratory tracts was the same or slightly low as compared with that of non-immune mice.     

Assessment of adult skeletons to detect prenatal exposure to acetazolamide in mice

A skeletal variant assay system (SVAS) consisting of a group of 88 spontaneously occurring qualitative variations of the adult mouse skeleton was applied to CD-1 animals that had been exposed in utero to 0, 200, or 1,000 mg/kg/day of the sodium salt of acetazolamide dissolved in distilled water, presented by SC injection of the dam during day 8 or days 9-11 of gestation. Two separate series of experiments were performed, and skeletons were examined at postnatal 62 +/- 2 days. Variation occurred in 62 and 67 characters in the two series. Frequencies of occurrence differed from untreated (UNTD) and vehicle-treated (VEH) values of substantial numbers of variants in a dose related manner for both series in both treatment regimes as did the number of variants which showed significantly different frequencies (P less than .01) in comparisons of experimental with either UNTD or VEH. At the high doses 12 and 16 variants occurred with significantly different frequencies from UNTD in day 8 treatments in the two series, and 15 and 19 variants differed in the days 9-11 treated group. Contrasting high-dose animals with appropriate vehicle controls revealed differences in 13 and 12 variants in day 8 treatment groups and in 18 and 15 variants in days 9-11 groups. Agreement between the two series was good, especially in the D9-11 treatments. Several variants differed significantly from both UNTD and VEH in both series of experiments. Among these were a number which appeared more or less specific to acetazolamide exposure. They include: day 8 treatments--accessory parietal, frontal extension, and 27 presacral vertebrae; day 9-11 treatments--sacral fusions in dorsal processes and vertebral bodies, and caudal fusions and malformations; both sets of treatments--lumbar fusions, and fusions of the transverse processes of the sacral vertebrae. Other importantly affected variants, also seen in exposure to other compounds include: day 8 treatments--abnormal metoptic roots; day 9-11 treatments--accessory mental foramen, foramina transversaria imperfecta of the atlas, arch foramen of the fifth cervical (C) vertebra, malformed sternebrae, fossa olecrani perforata, and fewer than 30 caudal vertebrae; both treatment regimes--parted frontals, accessory transverse foramina in C3-C6, reduced articular processes on the thoracic vertebrae, and 14 ribs. By all criteria applied, the SVAS is able to detect prenatal exposure to acetazolamide in adult skeletons even in the absence of any gross morphological abnormalities.     

Postnatal oxytocin alleviates adverse effects in adult rat offspring caused by maternal malnutrition

Repeated oxytocin administration to adult rats causes a long-term decrease of plasma levels of corticosterone and blood pressure and stimulates growth and fat retention. Maternal undernutrition increases blood pressure and plasma corticosterone in adult offspring. We hypothesized that oxytocin treatment early in life would alleviate adverse effects of intrauterine food restriction. Male pups from ad libitum-fed and food-restricted (fed 60% of ad libitum intake) dams were injected with oxytocin or saline in days 1-14 after birth. At 4 mo, blood pressure, plasma levels of corticosterone, and adiposity were assessed. Oxytocin treatment decreased blood pressure independently of nutrition, whereas the increased plasma levels of corticosterone were lowered to normal levels in food-restricted offspring. Blood pressure and adiposity were not affected by in utero food restriction, whereas birth and adult weight were. In conclusion, postnatal events may alleviate adverse effects caused by in utero food restriction. In contrast to more severe food restriction, a moderate general food restriction during gestation had no effect on blood pressure in the offspring.     

A prospective study of maternal and fetal outcome in acute Lassa fever infection during pregnancy.

Several viral infections have been reported to result in more severe disease in pregnant than non-pregnant women, but the relative risks have not been well characterised. This has now been done for Lassa fever in a prospective study of 68 pregnant and 79 non-pregnant women who were admitted to hospital in Sierra Leone with confirmed Lassa fever. Lassa fever was the main cause of maternal mortality in the hospital, accounting for 25% of maternal deaths. Twelve of 40 patients in the third trimester died, compared with two of 28 in the first two trimesters and 10 of 79 non-pregnant women. The odds ratio for death in the third trimester compared with the first two trimesters was 5.57 (95% confidence intervals 1.02 to 30.26). The condition of the mother improved rapidly after evacuation of the uterus, whether by spontaneous abortion, evacuation of retained products of conception, or normal delivery; 10 of 26 women without uterine evacuation died, but only four of 39 women with evacuation died (p = 0.0016). The odds ratio for death with pregnancy intact was 5.47 (95% confidence interval 1.35 to 22.16). Fetal and neonatal loss was 87%. The risk of death from Lassa fever in the third trimester is significantly higher than that in the first two trimesters and higher than that for non-pregnant women, but evacuation of the uterus can significantly improve the mother''s chance of survival.     

Delayed effects of prenatal or postnatal exposure to diethylstilbestrol in the adult female guinea pig

Of 25 mature female guinea pigs exposed transplacentally to diethylstilbestrol (DES) for more than 20 days before term, 8 showed abnormal changes in the genital tract (stimulation of the epithelium and stroma, cystic glandular hyperplasia of the endometrial glands near the junction of the upper endocervix and endometrium) and 9 showed severe changes (cystic glandular hyperplasia of the endometrial glands throughout the corpus uteri and cornua, squamous metaplasia). Hyperkeratosis of the vulvar and nipple skin was also observed. No neoplastic changes were observed with one exception at 14 months in one ovary. Prenatal exposure to DES for less than 15 days before term or after birth for 3 days failed to result in abnormal changes in the adults. Prenatal exposure to estradiol for more than 20 days also was without effect in the adult, despite the higher tolerated doses given to the mothers. Cycling activity as judged by vaginal opening was abnormal in all experimental groups, suggesting a derangement of the pituitary-hypothalamic function not specifically related to DES exposure. It was concluded that there is a critical period of exposure of the Müllerian duct- and sinus-derived tissues with respect to the delayed effects of prenatal exposure to DES, which is estimated on the basis of embryological studies to range from the 28th to about the 45th day of gestation.     

Early postnatal exposure of mice to side-steam tobacco smoke increases neuropeptide Y in lung

Our recent study showed that prenatal and early postnatal exposure of mice to side-steam tobacco smoke (SS), a surrogate to environmental tobacco smoke (ETS), leads to increased airway responsiveness and sensory innervation later in life. However, the underlying mechanism initiated in early life that affects airway responses later in life remains undefined. The concomitant increase in nerve growth factor (NGF) after exposures suggests that NGF may be involved the regulation of airway innervation. Since NGF regulates sympathetic nerve responses, as well as sensory nerves, we extended previous studies by examining neuropeptide Y (NPY), a neuropeptide associated with sympathetic nerves. Different age groups of mice, postnatal day (PD) 2 and PD21, were exposed to either SS or filtered air (FA) for 10 consecutive days. The level of NPY protein in lung and the density of NPY nerve fibers in tracheal smooth muscle were significantly increased in the PD2-11SS exposure group compared with PD2-11FA exposure. At the same time, the level of NGF in lung tissue was significantly elevated in the PD2-11SS exposure groups. However, neither NPY (protein or nerves) nor NGF levels were significantly altered in PD21-30SS exposure group compared with the PD21-30FA exposure group. Furthermore, pretreatment with NGF antibody or K252a, which inhibits a key enzyme (tyrosine kinase) in the transduction pathway for NGF receptor binding, significantly diminished SS-enhanced NPY tracheal smooth muscle innervation and the increase in methacholine-induced airway resistance. These findings show that SS exposure in early life increases NPY tracheal innervation and alters pulmonary function and that these changes are mediated through the NGF.     

Effect of exposure to high isoflavone-containing diets on prenatal and postnatal offspring mice

Isoflavone (IF), a type of phytoestrogen, has multiple beneficial effects, but too much phytoestrogen can have adverse effects on offspring. To examine whether chronic exposure to high IF has adverse effects on reproductive development, mice offspring were exposed to IF through dietary administration to dams during pregnancy and lactation and to the offspring directly after weaning until sacrifice. In male offspring, there was no difference between the IF group and controls; however, in female offspring in the IF group, remarkably earlier puberty and induction of multioocyte follicles on postnatal day (PND) 21 were observed. Gene expression levels of estrogen receptor beta decreased in the ovary and vagina on PND 21. These results suggest that chronic exposure to higher than normal levels of IF induces alterations in the reproductive development of female mice through an estrogenic effect.     

Effect of malnutrition on rotavirus infection in suckling mice: kinetics of early infection

The effects of malnutrition on the viral replication pattern and severity of clinical disease were examined in suckling mice infected with mouse rotavirus (MRV). The infection in malnourished animals was characterized by a significant decrease in the minimal infectious dose and in the incubation period of the onset of diarrhea, when compared to well-nourished controls. Viral replication in the dispersed enterocytes was observed 6-12 hr earlier, fecal viral shedding peaked significantly earlier, and the clinical disease appeared to be more severe in the malnourished animals than in the controls. These observations provide strong evidence for malnutrition-induced alterations in the pathogenesis of rotaviral infection in vivo.     

Assessment of adult skeletons to detect prenatal exposure to trypan blue in mice

A Skeletal Variant Assay System (SVAS) consisting of a group of 88 spontaneously occurring qualitative variations of the adult mouse skeleton was studied in CD-1 mice which had been exposed in utero by way of three daily ip injections of their dams on days 7-9 of gestation with trypan blue. Treatment groups received daily doses of 0.25 cc of 0, .037, .075, .15, or .30% trypan blue dissolved in 0.9% NaCl. Two separate series of experiments were performed, and skeletons were examined at 62 +/- 2 days postnatal. Sixty-six and 58 of the variants occurred in the two series, respectively. Frequencies of occurrence of substantial numbers of variants differed from Untreated (UNTD) and Vehicle-Treated (VEH) values in a dose-related manner for both series. At the high dose 18 and 22 variants occurred with significantly different (P less than .01) frequencies from UNTD in the two series. Contrasting high-dose animals with vehicle controls revealed significant differences in 24 and 17 variants. There were 13 and 14 variants in the two series, respectively, which differed from both UNTD and VEH. If one considers differences at P less than .01 in one comparison and P less than .05 in the other, then 22 and 18 variants qualify as being significantly different from both controls in the two series. Agreement between the two series was excellent regarding which variants were affected. Several differed significantly from both UNTD and VEH in both series of experiments. Among these were a number which appeared more or less specific to trypan blue exposure. They include Dyssymphysis of the Atlas, Carpal Fusions, and Tarsal Fusions. Although increased frequency of an Interfrontal bone is seen with several treatments, the magnitude of the response and the low doses at which it is elicited are unique to trypan blue exposure. Numerous low-dose effects are striking in this set of experiments, making the SVAS a very sensitive indicator of trypan blue exposure. In addition to the variants mentioned, a large cluster of cervical (C) vertebrae variants, including dyssymphyses, fusions, imperfect transverse foramina of C1 and C2, and accessory transverse foramina of C3-C6, as well as vertebral fusions at various levels (especially cervical, sacral, and caudal), appear to be the principal effects of exposure to this compound. In addition, rib malformations at the high dose level, and increased frequency of occurrence of 27-presacral vertebrae at all dose levels, were important effects.(ABSTRACT TRUNCATED AT 400 WORDS)     

Dynamic metabolic response of mice to acute mequindox exposure

Mequindox is used as a veterinary antibiotic drug. As part of systematic investigations into mequindox as a veterinary medicine and its subsequent applications in food safety, we conducted the investigation to assess the metabolic response of mice to mequindox using metabonomics, which combines NMR metabolic profiles of biofluids or tissues and pattern recognition data analysis. In this study, we delivered a single dose of mequindox to mice with dosage levels of 15, 75, and 350 mg/kg body weight and collected urine samples over a 7 day period, as well as plasma and liver tissues at 7 days postdose. Principal components analysis (PCA) and orthogonal projection to latent structure discriminant analysis (O-PLS-DA) were performed on (1)H NMR spectra of biofluids and liver, showing that low dose levels of mequindox exposure had no adverse effects, consistent with histological observations of the liver. High and moderate levels of mequindox exposure caused suppression of glycolysis and stimulation of fatty acid oxidation accompanied with increased levels of oxidative stress. Our metabonomic analyses also showed disruption of amino acid metabolism, consistent with liver damage observed from histopathological examinations. Furthermore, mequindox perturbed gut microbial activity manifested in the altered excretion of urinary trimethylamine (TMA), trimethylamine-N-oxide (TMAO), hippurate, phenylacetylglycine (PAG), and phenylacetate. The putative gut microbial function may also contribute to the assembly and secretion of very-low-density lipoproteins from the liver to the plasma. Our work provides important insights on the metabolic responses of mequindox.     

Vaccination in murine schistosomiasis with adult worm-derived antigens: variables influencing protection in outbred mice

Previous studies have shown that both permissive (mouse) and partially permissive (rabbit) hosts develop high levels of resistance against Schistosoma mansoni infection after vaccination with a multiple antigen extract (SE) obtained by incubation of living adult worms in saline, plus bacterial adjuvant. To investigate variables influencing SE-induced protection in murine schistosomiasis, a series of distinct vaccination protocols were performed focussing on the immunization dose, carrier systems, route, site and amplitude of challenge infection, and time between immunization and challenge. In addition, a new approach was adopted to evaluate SE protective activity, by means of population analysis of worm burden frequency distributions in a large scale study of vaccination in outbred Swiss mice. Distinct curves of frequency and a drastic difference in worm burden distribution of frequencies from SE-vaccinated x non-vaccinated mice were found. It was shown that SE could generate 75% mean protection in outbred mice even in the absence of adjuvant. In addition SE immunization was also able to induce full protection against lethal infection. SE-induced protection could be modulated by such parameters as dose of SE immunization/challenge interval, and route of cercariae injection. These data show that SE yields very high protective activity in outbred mice, and may provide a further insight for rational design of a vaccine in experimental schistosomiasis.