Taste responses in wild and domestic guinea pigs

Responses of male wild (Cavia aperea) and domestic (C. Porcellus) guinea pigs to stimuli representing the taste qualities sweet, salty, sour and bitter were monitored in two bottle choice tests. Wild cavies showed statistically significant preferences for .008–.25 M NaCl and .001–.031 M sodium saccharin and rejected 1.0 M NaCl and .063 M citric acid. Domestic cavies' acceptances of solutions preferred by the wild form were lower on first series of presentations but increased to the level of C. aperea upon representations. C. porcellus rejected citric acid (.031 M), NaCl (.5 M) and sucrose octaacetate (.001 M) at concentrations not rejected by the wild type. Wild cavies did not reject SOA at any concentration and neither type rejected quinine sulfate. Absence of bitter rejection was postulated to be an adapatation useful to some herbivores. Changes in acceptance data over time and the interference of position preference with responses to solutions suggested the major difference between types to be the wild cavies' greater readiness to orient to stimulus cues.     

Survey of genetic diversity of IgG in wild and domestic rabbits

We sequenced IgG from genomic DNA of 30 wild European rabbits of O. c. algirus and O. c. cuniculus subspecies from three regions and 15 domestic O. c. cuniculus. Genetic diversity was highest within Iberian wild populations. Only two new amino acid polymorphisms were found, both in O. c. algirus.     

Individual variations in the development of motor activity of rabbits in the early postnatal period

Summary Data presented in this work confirm P. S. Kupalov's observations on the presence of so-called explosiveness in the activity of pathologically unaffected cortical cells. At the same time it is pointed out that phenomena of explosiveness of the nervous processes with reduction of the positive conditioned reflexes may serve as a symptom of preneurotic state.(Presented by Active Member AMN SSSR P. S. Kupalov) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 54, No. 9, pp. 8–10, September, 1962     

Hormonal responses accompanying fear and agitation in the squirrel monkey

The adrenocortical and gonadal responses of 14 male monkeys were evaluated during four experimental conditions in order to evaluate the influence of social interactions on endocrine responsiveness. Plasma hormone levels were determined during the establishment of social relations, after 60-min exposures to a novel environment, after 60-min exposures to a snake, and 60 min after ACTH administration. Both adrenal and gonadal secretion changed significantly during the first day after social relations were established, although only dominant males showed increases in testosterone, whereas cortisol levels rose in all subjects. Increases in cortisol, but not testosterone, were also observed following exposure to novelty or a snake. The presence of a social partner reduced signs of behavioral disturbance during these test conditions, although the adrenal responses were equivalent or greater than when tested alone. This finding qualifies earlier research which indicated that social support was beneficial for reducing stress when squirrel monkeys were tested in larger groups in their home environment.     

Toxoplasma gondii in sympatric domestic and wild ungulates in the Mediterranean ecosystem

Parasitology Research - Toxoplasma gondii is a zoonotic protozoan of worldwide distribution. The present study provides information on risk factors affecting T. gondii infection in domestic and...     

A study of human foot length growth in the early fetal period.

The length of the human fetal foot was studied in 106 feet from 53 unfixed staged human fetuses (35 males and 18 females) by means of the allometric formula log Y = log b+k log X. The gestational age ranged from 13 to 26 weeks postconception. The measurement taken from the heel to the tip of the longest toe was regarded here as the maximum length of the foot. Growth in length of the foot was analysed in relation to crown-rump length. Our results show that foot length growth is correlated to crown-rump growth and is allometrically positive. No statistically significant difference was found between right and left feet or between male and female fetuses.     

Long-lasting behavioral and neuroendocrine changes provoked in rabbits by cancelling a single nursing bout in early lactation

To restore estrus in lactating doe rabbits, nursing was prevented on lactation day 10 and allowed again from day 12 onward. This “biostimulation” procedure, used to accelerate reproduction, allows kit survival despite a 48 hr fast. Yet, the consequences of “biostimulation” on their psychobiological and neuroendocrine development are largely unknown. Therefore, we determined, in adult males and females, tested in the morning or afternoon: corticosteroid secretion (baseline and reactive), sexual behavior, and responses in six tests measuring stress/anxiety. The latter were not affected by maternal deprivation or time of testing in either sex. The lordosis quotient was reduced in deprived does (relative to controls), an effect eliminated when only non-kins (of both groups) were compared. Deprived males showed altered sexual behavior, evidenced by a large number of mounts not culminating in ejaculation. Corticosterone and cortisol secretion increased (relative to baseline) following i.m. saline in all groups, but the magnitude of the response was affected by maternal deprivation, time of day, and sex. Results indicate that particular behaviors and reactivity to stress have different thresholds regarding the effects of mother–litter separation in early lactation.     

Impairment in T-lymphocyte responses during early infection with the human immunodeficiency virus

Uncertainty has existed as to whether a T-cell deficiency exists in human immunodeficiency virus (HIV) infection different from that inherent in the reduced T-cell numbers characteristic of the disease. Heretofore, methods for measuring T-cell responses in patients have been carried out with systems requiring monocytes as accessory cells. In the presence of high concentrations of interleukin-2, however, highly purified T cells respond in a monocyte-independent fashion to antibody reactive with the CD3 component of the antigen receptor complex Ti/CD3. Highly purified T cells of HIV-infected patients responded subnormally in this anti-CD3/IL-2 system, even in the case of patients who were asymptomatic or had only lymphadenopathy. The defective T-cell responses occurred over a wide range of concentrations of the anti-CD3. Neither poor IL-2 receptor function as reflected by responses to limiting dilutions of IL-2 nor IL-1 receptor function as defined by incremental proliferation when IL-1 is added accounted for this defect, which also correlated poorly with T4 and T8 numbers. These results suggested that the T-cell abnormality was closely related to Ti/CD3 function, was not specifically or restrictively associated with T4 cells, and was not due to defective IL-2- or IL-1-receptor functions. The amount of HIV RNA in 10⁵ T lymphocytes from the patients amounted to less than that found in one cell of a standard HIV infected laboratory cell line (CEM), using slot-blot hybridization. Thus the T-cell deficiency we have observed was not likely to be due directly to cell killing by HIV resident in the T4 cells. Other factors may be important in inducing the immunodeficiency, some of which are discussed.     

Vaccination in the neonatal period and early infancy

Immune maturation is responsible for a progressive increase in antibody responses that can be elicited during the first year of life, such that neonatal immunization may currently not be expected to induce strong antibody responses. In contrast, B and T cell priming can be induced very early in life, without interference of maternal immunity. Strong IL-5 and IL-13 responses in young mice, and limited IL-12 and IFN-gamma release capacity by early life APC and T cells both in young mice and infants, could contribute to the severity of infections with intracellular pathogens in early life. It calls for evaluation of novel delivery systems, adjuvants and/or prime-boost immunization strategies capable to meet the challenge of both strong neonatal immunogenicity and acceptable reactogenicity. The extent to which early life murine immunization models may be useful for preclinical evaluation of infant responses is outlined in this review.     

Beta-endorphin and the endocrine pancreas. Studies in healthy and diabetic human beings

Beta-endorphin is present in the endocrine pancreas, suggesting that endorphins may have a role in islet-cell function. To evaluate this possibility, we infused synthetic human beta-endorphin intravenously in healthy volunteers and in insulin-dependent diabetic patients. In both groups, beta-endorphin increased plasma glucagon concentrations, and this rise was accompanied by a significant increase in plasma glucose concentrations. In nondiabetic subjects, beta-endorphin also increased plasma insulin concentrations. The threshold dose of beta-endorphin for producing increased plasma concentrations of glucose and glucagon was 0.005 mg--a dose that acutely increased plasma concentrations of beta-endorphin by approximately 40-fold. Glucose, glucagon, and insulin responses to beta-endorphin could not be blocked by intravenous naloxone. These studies suggest that endorphins may be involved in gluco-regulation, that their hyperglycemic action is mediated at least in part by glucagon, and that the effect of beta-endorphin on islet-cell function is relatively resistant to naloxone.     

Comparison of the effects of early handling and early deprivation on maternal care in the rat

It has been reported in the rat that postnatal manipulations can induce robust and persistent effects on offspring neurobiology and behavior, mediated in part via effects on maternal care. There have, however, been few studies of the effects of postnatal manipulations on maternal care. Here, we describe and compare the effects on maternal behavior on postnatal days 1-12 of two manipulations, early handling (EH, 15-min isolation per day) and early deprivation (ED, 4-hr isolation per day), relative to our normal postnatal husbandry procedure. Maternal behavior was measured at five time points across the dark phase of the reversed L:D cycle. EH yielded an increase in arched-back nursing across several time points but did not affect any other behavior. ED stimulated a bout of maternal behavior such that licking and arched-back nursing were increased at the time of dam-litter reunion, although not at any other time point. Neither EH nor ED affected weaning weight significantly. Importantly, within-treatment variation was high relative to these between-treatment effects.     

Maltose: the primary signal of hunger and satiation in human beings.

In rats, blood glucose concentration serves as the primary signal responsible for the induction of the sensation of hunger. In human beings, however, blood glucose concentration has been shown not to be the primary signal for the production of hunger sensation. Disaccharide, in the form of lactose in milk, sucrose in nature, and maltose from the breakdown of starch in the mouth, is part and parcel of human diet. The present study tested the hypothesis that maltose could be the primary signal responsible for the induction of the sensation of hunger and satiation in human beings. The hunger-moderating effect of maltose was compared with that of glucose by applying the test materials to the sweet-sensing taste buds on the tongue. Even at lower dosages, the effect of maltose was significant. At higher dosages, both glucose and maltose caused significant moderation of hunger. Maltose, a disaccharide, can be the agent responsible for the primary signals to induce the sensations of hunger and satiation in human beings.     

Oestrogen status in relation to the early training responses in human thumb adductor muscles

Aims: The aims of this study were to identify the mechanisms for the early response to training in women of different oestrogen status and to determine whether any oestrogen and exercise effects on these would be additive. Methods: We monitored training (ten 5‐s contractions per day for 12 weeks)‐induced changes in the size, strength, voluntary activation capacity and index of crossbridge force state (i.e. rapid stretch to isometric torque ratio), in the thumb adductor muscles of postmenopausal [eight who had never used, and 14 who were using, hormone replacement therapy (HRT)] and seven premenopausal eumenorrhoeic women. The contralateral untrained muscle was used as a control. Results: There was a significant effect of oestrogen status on the magnitude of training‐induced strength increment, with the non‐HRT postmenopausal group exhibiting the greatest benefits (28 ± 6%, P = 0.024) from training. There were no significant or commensurate changes in either cross‐sectional area or voluntary activation capacity. The index of crossbridge force state improved most in the no‐HRT group (19 ± 7%, P < 0.05). Conclusions: Presence, rather than absence of oestrogen, is associated with relatively higher muscle function which limits the potential for any further training‐induced increments in muscle performance, as would be expected if the muscle strengthening actions of training and oestrogen share a common, partially saturable physiological pathway. The mechanism that is involved in the early training‐induced strength increment in the three differing oestrogen groups cannot be due to increased size or recruitment. It would appear instead that increased motor unit firing frequency is involved.