Theory of nucleus breeding schemes with overlapping generations

Summary Explicit methods are derived for estimating steady-state genetic responses and genetic differences between nucleus and base progeny crops in open nucleus breeding schemes which utilize genetic differences between progeny groups with parents of different ages or between age groups. Explicit methods are also given for estimating proportions which should be selected from the different nucleus and base selection groups so as to maximise genetic responses under each of a range of selection methods. Some basic differences between selection programmes utilizing genetic differences between progeny groups with parents of different ages and those utilizing genetic differences between age groups in nucleus breeding schemes are summarized.     

Goiter in Tibetan Medicine

The visit of two Tibetan physicians provided a unique opportunity to gain insight into a practice of medicine very different from that of Western civilization. Initial discussions indicated that the practice of medicine and mysticism were inextricably interwoven in the Tibetan culture. Accordingly, the focus of the study was directed to goiter, which is both common in the Himalayas and easy to define.In Tibetan medical practice, illness is considered to be derived from both proximate and distant causes. Three humors, “wind,” “bile,” and “phlegm” are thought to be responsible for normal mental and physical functions when in balance, but disease when out of balance. Goiter was thought to be due to an imbalance of these humors. The Western discovery that endemic goiter in the Himalayas was due to iodine deficiency explained the proximate cause but did not explain why some individuals have goiter and others do not in the same iodine deficient village.     

Interleukin-6 is a centrally acting endogenous pyrogen in the rat.

Intracerebroventricular (i.c.v.) injection of human recombinant interleukin-6 (IL-6; 20-100 ng) caused significant increases in colonic temperature and resting oxygen consumption (VO2) in conscious rats. These effects were prevented by pretreatment with a cyclooxygenase inhibitor (flurbiprofen, 1 mg/kg, i.p.) or a corticotrophin-releasing factor antagonist (alpha-helical CRF9-41, 25 micrograms, i.c.v.). Higher doses of IL-6 (i.c.v.) caused only small changes in VO2 and temperature, and very high doses given intravenously (i.v.) (4 micrograms/kg) were required to stimulate these parameters. Central injection of anti-rat IL-6 antibody inhibited the effects of interleukin-1 beta (i.c.v.) or endotoxin injection (i.p.) on colonic temperature and VO2 in conscious rats. These data indicate that IL-6 is an important endogenous pyrogen that acts within the central nervous system.     

Inactivation kinetics and pharmacology distinguish two calcium currents in mouse pancreatic B-cells

Summary Voltage-dependent calcium currents were studied in cultured adult mouse pancreatic B-cells using the whole-cell voltage-clamp technique. When calcium currents were elicited with 10-sec depolarizing command pulses, the time course of inactivation was well fit by the sum of two exponentials. The more rapidlyinactivating component had a time constant of 75±5 msec at 0 mV and displayed both calcium influx- and voltage-dependent inactivation, while the more slowly-inanctivating component had a time constant of 2750±280 msec at 0 mV and inactivated primarily via voltage. The fast component was subject to greater steady-state inactivation at holding potentials between –100 and –40 mV and activated at a lower voltage threshold. This component was also significantly reduced by nimodipine (0.5 m) when a holding potential of –100 mV was used, whereas the slow component was unaffected. In contrast, the slow component was greatly increased by replacing external calcium with barium, while the fast component was unchanged. Cadmium (1–10 m) displayed a voltage-dependent block of calcium currents consistent with a greater effect on the high-threshold, more-slowly inactivating component. Taken together, the data suggest that cultured mouse B-cells, as with other insulin-secreting cells we have studied, possess at least two distinct calcium currents. The physiological significance of two calcium currents having distinct kinetic and steady-state inactivation characteristics for B-cell burst firing and insulin secretion is discussed.     

Cognitive and behavioural impairment among elderly people in institutions providing different levels of care.

OBJECTIVE: To compare the prevalence and degree of cognitive and behavioural impairment in elderly patients in institutions providing different levels of care. DESIGN: Prevalence study. SETTING: A nursing home, a home for the aged and psychogeriatric wards in a provincial psychiatric hospital. PATIENTS: Only subjects 65 years of age or older were eligible for inclusion. A random sample was selected comprising 25% of the residents in the nursing home and the home for the aged; of the 119 asked to participate 95 agreed (44 in the nursing home and 51 in the home for the aged). All 50 on the psychogeriatric wards agreed to participate. MAIN OUTCOME MEASURES: The Mini-Mental State Examination (MMSE) and the Kingston Dementia Rating Scale (KDRS). RESULTS: An MMSE score of less than 24 (cognitive impairment) was given to 37 (84%) of the residents in the nursing home, 43 (84%) of those in the home for the aged and 48 (96%) of the patients in the psychiatric hospital; the corresponding numbers for a KDRS score of more than 0 (cognitive impairment) were 41 (93%), 48 (94%) and 50 (100%). The seven patients receiving the highest level of care at the home for the aged (special care) had more behavioural problems than those in the psychiatric hospital did (p less than 0.001). CONCLUSIONS: Cognitive and behavioural impairment was widespread in the three institutions regardless of the level of care. When planning services and allocating resources government funding agencies should consider the degree and prevalence of such impairment among elderly people in institutions.