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Biomedical subjects

E Brenner

Publications and source records attributed to E Brenner.

100 records · Page 6Linked to original sources
PubMed1984

Effects of cooling in infant rats on growth, maturation, sleep patterns and responses to food deprivation.

The confounding effects of undernourishment and body cooling, resulting from maternal separation, were investigated by separating food and warmth deprivation. Rat pups aged 3-16 d were deprived of food for alternate 24-h periods by removal from the lactating mother. Some of the pups were placed with a foster mother, who kept them warm, whereas others were put in an empty cage at 22 degrees which resulted in a sharp drop in body temperature. Pups which were kept warm showed great fluctuations in weight between periods of starvation and feeding. The cooled pups lost less weight during deprivation but also recovered less on refeeding. The resultant growth rate was much lower in non-fostered (i.e. cooled) than in fostered pups. Up to the age of 8 d, cooled pups failed to raise their body temperature above that of the surroundings and did not digest the milk in their stomachs. Although, thereafter, they were able to raise their temperature to 26 degrees and to digest stomach contents, the extra energy expended resulted in more severe growth restriction. One-third of the pups died at 16 d but the rest were quickly rehabilitated by ad lib. feeding and showed a normal growth rate, although they remained smaller than the controls. The development of nipples, hair, eye opening and vaginal opening was related more to chronological age than to weight. A side effect of cooling was an almost complete abolition of active (REM) sleep, which is normally very high in infants; a slight rebound increase in active sleep was seen at 21 d. Direct as well as side effects of cooling may thus be responsible for some of the observed consequences of maternal separation.

Animals↗
PubMed1983

Impaired growth of the cerebral cortex of rats treated neonatally with 6-hydroxydopamine under different environmental conditions.

Male Wistar rat pups received subcutaneous injections of either 100 mg/kg 6-hydroxydopamine (6-OHDA) or saline on days 1, 3, 5 and 7. The noradrenaline (NA) content of the cerebral cortex was reduced by 70% while sleep registration during the first two weeks of life did not show any significant differences between drug- and saline-treated animals. After weaning (day 25), both 6-OHDA- and saline-injected animals were reared under standard and enriched environmental conditions. Whereas a clear increase in cerebral cortical weight after experience with an enriched environment was found in saline-treated rats, 6-OHDA-treated animals had lower cortical weights and showed less increase due to the environment. These results demonstrate that catecholamine neurotransmission during early development influences the development and plasticity of the cerebral cortex.

Animals↗
PubMed1983

Early colour deprivation in the pigeon.

When cats and monkeys are deprived of specific stimuli during an early sensitive period the development of their visual system is known to be affected. In pigeons, pattern discrimination learning has been shown to be affected by monocular deprivation [2]. Our study was set up to examine whether colour discrimination learning could be affected by colour deprivation. Young pigeons were reared under restricted colour illumination for at least 3 months after hatching so as to obtain a group bred under red illumination, one bred under blue illumination and a control group. After this period several psychophysical tests were used to test the pigeons' sense of colour. No significant difference was found between the 'deprived' birds and the controls. The spectral sensitivity, determined with the help of the ERG, did not differ for the three groups. We conclude that early colour deprivation does not affect visual development in the pigeon.

Animals↗
PubMed1982

Influence of growth medium, age in vitro and spontaneous bioelectric activity on the distribution of sensory ganglion-evoked activity in spinal cord explants.

The role of serum added to the culture medium and of spontaneous bioelectric activity in the development of sensory afferent connections was studied, employing fetal mouse spinal cord explants with attached dorsal root ganglia (DRG) as an in vitro model system. Afferent DRG terminals in the cord explants were localized on the basis of 'fixed-latency' DRG-evoked action potentials, which were anatomically verified in several experiments using horseradish peroxidase histology. In serum-supplemented medium (HSSM), but not in chemically defined medium (CDM), those DRG fibers which grew into the dorsal side of the cord terminated predominantly within the dorsal cord region, and remained there throughout the experimental period (18-33 days in vitro). In contrast, ventrally entering fibers terminated equally in both the dorsal and the ventral cord regions in young cultures (18-24 days in vitro) but were no longer observed after 27 days in vitro. Cultures grown in HSSM with the addition of xylocaine, in order to chronically suppress spontaneous bioelectric activity, essentially corresponded (at 25-32 days in vitro) to the picture seen in the control series at the same age. On the basis of polysynaptic DRG-evoked responses in the cord, developmental changes in local neuronal networks were inferred which resulted in less spread of DRG-evoked activity with age in HSSM, and more spread with age in CDM-grown cultures. It is concluded that for the formation of selective DRG connections in the spinal cord: (i) a serum-borne factor plays a role: and (ii) functional activity is not required.

Animals↗
PubMed1981

Chemically defined medium enhances bioelectric activity in mouse spinal cord-dorsal root ganglion cultures.

Co-cultures of mouse spinal cord with dorsal root ganglion (DRG) cultures were grown either in horse serum (HS)-supplemented medium or in a serum-free, chemically defined medium (CDM). The cytoarchitecture of cord--DRG explants was fully retained in CDM, with little or no distortion due to flattening of the explant, as is invariably observed in HS-supplemented cultures. Functional properties such as bioelectric activity and DRG--spinal cord interconnectivity were well sustained in CDM.

Animals↗
PubMedDate not supplied

An epidemiologic model for diabetes mellitus: incidence, prevalence, and mortality.

An epidemiologic model is developed to describe the incidence, prevalence, and mortality of diabetes. Available data are reviewed, analyzed, and applied to the model. The model provides a framework for understanding diabetes on a population basis, and is useful in identifying needs and facilitating health care planning.

Adult↗
PubMedDate not supplied

Neurochemical and electrophysiological disturbances mediate developmental behavioral alterations produced by medicines.

Many centrally acting drugs which are prescribed for hypertension, depression, epilepsy, insomnia and asthma may also affect fetal brain neurotransmission and behavioral states. Nearly all these drugs enter the fetal circulation following maternal administration. The immaturity of the blood-brain barrier and greater accumulation in the developing brain make the fetal brain a major target of its mother's medication. Adverse effects that are seen in the fetus are not necessarily evident in its mother. We have shown that drugs like clonidine (an antihypertensive) and clomipramine (an antidepressant), which act on noradrenaline and serotonin neurotransmission in the brain, suppress rapid eye movement sleep in the developing rat. In adulthood, the neonatally treated rats showed hyperactivity, hyperanxiety, reduced sexual behavior, disturbed sleep patterns and reduced cerebral cortical size. Furthermore, such treatment induced an increase in voluntary alcohol consumption and a decreased adaptability of responses to changes in water deprivation in a Y-maze. Little is known about long-lasting consequences of centrally acting drugs used during late gestation in humans. Minor neurological disturbances, such as delayed visual motor performance, smaller head circumference, increased anxiety and disturbed sleep-wake patterns, have been reported in children born to hypertensive mothers treated with clonidine or alpha-methyl-dopa.

Aging↗
PubMedDate not supplied

[An innovative program for public health training at the University of Geneva. Program during employment centered on the student and oriented to the population's health needs].

Switzerland's first Master degree course in public health was launched in the autumn of 1990 at the Geneva University School of Medicine. It is a 3 year, part-time course, which is learner-centred and community-oriented. The aim of the course is to prepare students to use a multi-disciplinary approach to plan, implement and evaluate activities intended to solve public health problems. Throughout the course, studies plan, implement and evaluate projects concerning health problems they have encountered in their work as health professionals. The curriculum includes individual and group work, discussions and seminars with teachers and students, and brainstorming sessions with specially trained facilitators. The students can thus identify and fulfil individual educational objectives while working on community-related health projects. Priority health needs of individuals and communities are thus the pivotal points of the novel approach to public health training.

Curriculum↗