Photoperiod and tutor access affect the process of vocal learning

Song learning in white-crowned sparrows, Zonotrichia leucophrys, involves three steps: memorization of external models, song practice and selection of a song from the practiced repertoire for crystallization. These three events occur in a sequential and predictable order during the first year of life in captive sparrows. To study the external regulation of these events, we raised nestling sparrows under conditions in which photoperiod and tutor exposure were manipulated. We measured plasma testosterone concentration twice a month to study its role in the mediation of vocal learning. We conclude that the timing of song memorization is relatively impervious to photoperiodic manipulation. Song practice and crystallization, however, were readily influenced by both photoperiod and tutor exposure. We suggest that low testosterone concentrations permit acquisition at an older age than would normally occur, and confirm that testosterone propels the transition to production of crystallized song, but is not required for the onset of song practice. Copyright 1998 The Association for the Study of Animal Behaviour.     

Studying the mental health of a nation: a preliminary report on a population survey in Singapore

OBJECTIVE: Requirements for cytokines and adhesion molecules for peritoneal neutrophil recruitment during glycogen-induced peritonitis in rats were systematically defined. SUBJECTS: Male Long Evans rats (275-300 g). METHODS: Four hours after intraperitoneal injection of 25 mg oyster glycogen, neutrophilic exudates were harvested. Effects of blocking reagents (injected intravenously) to rat E-, L- and P-selectins, beta1 (VLA-4) and beta2 integrins (LFA-1 and Mac-1), ICAM-1, and the cytokines TNFalpha, IL- and IL-8 were assessed. RESULTS: Administration of synthetic sialyl Lewis(x) oligosaccharide reduced neutrophil recruitment to the peritoneum by 26%. Antibody to E-selectin reduced neutrophil accumulation by 71%, while anti-L-selectin reduced neutrophil accumulation by 59%, and anti-P-selectin was without an effect. Similar patterns of inhibition were found when selectin-Ig chimeras were employed. Antibodies to LFA-1 (CD11a), Mac-1 (CD11b) or CD18 reduced neutrophil accumulation by 62 percent, 59 percent and 86%, respectively, while anti-VLA-4 was without effect. Anti-ICAM-1 reduced cell influx by 65%. IL-1 receptor antagonist and antibodies to IL-1 and human IL-8 reduced neutrophil accumulation by 43alpha, 40% and 62 percent, respectively. Unexpectedly, blockade of TNFalpha had no effect. CONCLUSIONS: These studies identify requirements for selectins, beta2 integrins, IL-1 and a rat chemokine(s) similar to human IL-8 for neutrophil recruitment during glycogen-induced peritonitis. The lack of participation of VLA-4, P-selectin and TNFalpha suggests organ-specific cytokine and adhesion molecule requirements for neutrophil recruitment.     

Alterations in the opioid control of LHRH release from hypothalami isolated from aged male rats

Several lines of evidence have suggested that the opioid control of gonadotropin secretion in the male rat is altered with aging. Because neural control of gonadotropins is mediated through luteinizing hormone releasing hormone (LHRH) secreting neurons, we examined the postulated changes in the opioid control of gonadotropins more directly by studying isolated hypothalamic fragments in vitro. Hypothalami from young (75-90 days) and old (18-20 months) males were examined for their ability to release LHRH when incubated with increasing doses of naloxone in a semi-static culture system. Serum concentrations of testosterone and luteinizing hormone (LH) in the donor animals were both significantly lower in old male rats compared with young males. Basal secretion of LHRH was similar in both age groups. Two-way repeated measures ANOVA indicated that naloxone stimulated a significant dose-dependent increase in the release of LHRH into the media. ANOVA also indicated a significant effect of age. We conclude that the changes in the endogenous opioid systems reported to occur with aging are, in fact, linked to differences in LHRH secretion and thus to differences in the dynamic relationship between testosterone and LH in older male rats.     

Disseminated cutaneous rhinosporidiosis

Two cases of longstanding rhinosporidiosis developed widespread asymptomatic nodular skin lesions. Cutaneous examination showed multiple, discrete, sessile and pedunculated, smooth and warty, friable nodular lesions of variable sizes and shapes. Histopathology of representative skin lesions showed hyperplastic epidermis with sporangia containing spores in the upper dermis diagnostic of rhinosporidiosis. Epidemiological data about rhinosporidiosis at Jawaharlal Institute of Postgraduate Medical Education and Research (JIPMER), Pondicherry, India, is presented. Possible modes of dissemination to the skin and differential diagnosis are discussed in relation to this rare manifestation of rhinosporidiosis.     

Immunocytochemistry on the Thinprep processor

The title compound crystallizes in the zwitterionic form. The crystal forms a supramolecular structure with the peptide molecules organized in head-to-tail columns in the b direction. The arginine side-chains and acetate ions interact with neighbor peptides in the c direction. Infinite hydrophobic columns are present in the a direction; they involve the valine side-chains, the acetate methyl groups and the methylene groups of the arginine side-chains. This three-dimensional organization is similar to that found in Lys-Val hydrochloride.     

Fixed-time schedules attenuate extinction-induced phenomena in the treatment of severe aberrant behavior

We compared the effects of extinction (EXT) and fixed-time (FT) schedules as treatment for severe problem behavior displayed by 3 individuals with developmental disabilities. First, functional analyses identified the reinforcers maintaining aberrant behavior for all 3 individuals. Next, EXT and FT schedules were compared using a multielement design. During EXT, the reinforcer maintaining problem behavior was withheld. During FT, the reinforcers were presented response independently at preset intervals. Results showed that FT schedules were generally more effective than EXT schedules in reducing aberrant behavior. FT schedules may be used in situations when extinction-induced phenomena are problematic.     

The relationship between ethnoracial group and functional level in older persons

This paper reports on a participatory action research study which arose out of the initiatives of people caring for clients attending a multicultural dementia day-care program. Through a democratic decision making process, the day-care staff and family carers consulted with clients to design, implement and evaluate a new therapy program. The researchers acted as facilitators in this process, with a view to empowering participants at each stage in the action research cycles. What started out as a negative situation for the majority of study participants, evolved to become a satisfying group process and positive outcomes resulted from the therapy program itself. For clients there was the renewal of close personal relationships with family carers, increased alertness and a reduction in some of their distressing symptoms. For the family carers, there arose an awareness of new purposes in the caring role and therefore less distress in their daily lives, for day-care staff there emerged a re-conceptualisation of purpose of dementia care programs and the benefits to be gained from community collaboration in program design. The focus of this paper is to describe the action research process, which resulted in positive outcomes for the study participants.