Hearing status among Norwegian train drivers and train conductors.

BACKGROUND: There is a general perception that train drivers and conductors may be at increased risk of developing noise-induced hearing loss. AIMS: To study job-related hearing loss among train drivers and train conductors. METHODS: Audiograms from train drivers and train conductors were obtained from the medical records of the occupational health service of the major Norwegian railway company. The results were compared with audiograms from an internal control group of railway workers and an external reference group of people not occupationally exposed to noise. The monaural hearing threshold level at 4kHz, the mean binaural value at 3, 4 and 6kHz and the prevalence of audiometric notches (≥25 dB at 4kHz) were used for comparison. RESULTS: Audiograms were available for 1567 drivers, 1565 conductors, 4029 railway worker controls and 15 012 people not occupationally exposed to noise. No difference in hearing level or prevalence of audiometric notches was found between study groups after adjusting for age and gender. CONCLUSIONS: Norwegian train drivers and conductors have normal hearing threshold levels comparable with those in non-exposed groups.

The mechanistic basis of aerobic performance variation in red junglefowl.

We examined aerobic performance, organ and muscle mass and enzymatic activity in red junglefowl (Gallus gallus). We tested three models of performance limitation (central limits, peripheral limits, symmorphosis) and explored relationships between basal metabolic rate (BMR), aerobic capacity ( V (O2max)) and social rank. Males had a lower BMR, a higher V (O2max) and a greater aerobic scope than females. Females possessed larger peritoneal and reproductive organs, while males had larger hearts, lungs and leg muscles. In females, BMR was correlated with spleen mass and V (O2max) was correlated with hematocrit and large intestine mass. Male BMR was correlated with intestinal tract and lung mass, and V (O2max) was correlated with heart and pectoralis mass. Male citrate synthase activity averaged 57 % higher than that of females and was correlated with V (O2max) (this correlation was not significant in females). Female social status was not correlated with any variable, but male dominance was associated with higher aerobic scope, larger heart and lungs, smaller peritoneal organs and greater leg citrate synthase activity. We conclude that aerobic capacity is controlled by system-wide limitations (symmorphosis) in males, while in females it is controlled by central organs. In neither sex is elevated aerobic capacity associated with increased maintenance costs.

Testosterone and aggression in male red jungle fowl.

We investigated the relationship between aggression, plasma testosterone level (T), and change in T in captive male red jungle fowl (Gallus gallus). T measured on day 1 of our experiment was positively correlated with T on day 8, suggesting that T remains constant in males when the social environment is stable. During aggressive encounters that escalated to include physical combat, males that attacked first (won) had increased T relative to their opponent. Males did not differ in T measured 1 week before the aggressive encounter. Our data suggest that an increase in T during aggression is associated with winning in escalated fights.

Testosterone and avian life histories: the effect of experimentally elevated testosterone on corticosterone and body mass in dark-eyed juncos.

To assess whether alterations in the normal pattern of testosterone (T) secretion might be beneficial or detrimental, we studied a breeding population of dark-eyed juncos in which we elevated T experimentally and measured its effect on potential correlates of fitness. We treated both free-living and captive males with implants that were either empty (C-males, controls) or packed with T (T-males, experimentals). Timing of implant varied and was designed to mimic natural peak breeding levels except that peaks were either prolonged or premature. We bled the birds at recapture and analyzed their plasma, and that of their female mates, for T and corticosterone (B). We also measured body mass and fat score in free-living T- and C-males. In the field, T-implants elevated T and kept it elevated for at least a month. Experimental males also had higher B than controls. In captives, the effect of the implants on plasma T was detectable within 24 hr. B in captive T-males was again higher than in captive C-males. In females, neither T nor B differed between mates of T- and C-males. T-males implanted in early spring lost more mass between implant and recapture in late spring than did controls and also had lower fat scores when recaptured. When implants were inserted in summer, treatment did not influence mass. Elevated T in early spring apparently hastened the transition from the winter to the breeding mode of fat storage. We suggest that prolonged elevation of testosterone might be selected against because of the association between T and B. Premature elevation of T might be costly because of the resultant loss of mass and fat reserves, which could lead to mortality when spring snowstorms prevent access to food.

[Cholesterol level among school children. Cholesterol measurements in adolescents in a municipality in Finnmark and a municipality in Sogn and Fjordane]. / Kolesterolnivå blant ungdomsskoleelever. Kolesterolmålinger av ungdommer i en Finnmarks-kommune og en kommune i Sogn og Fjordane.

This article reports a survey conducted to measured serum cholesterol in pupils aged 13-16 years in a municipality in the county of Finnmark and in a municipality in the county of Sogn og Fjordane. Cholesterol levels were analysed and information was collected by questionnaire on eating habits, smoking habits and occurrence of cardiovascular disease in the family. We did not find any differences between the two communities in respect of cholesterol level, nor any relationship between eating habits and cholesterol level. Pupils with parents and/or grandparents with cardiovascular disease had a significantly higher cholesterol level than pupils with no such disease in their family.

Variability of symphysis-fundus height measurements: an experimental study among general practitioners.

With the aim of evaluating the impact of supervised training during a postgraduate course in obstetrics and gynaecology, the variability of symphysis-fundus (SF) height measurements was studied by a group of general practitioners (GPs), all of whom provided primary antenatal care. A nested analysis of variance was used. The SF height measurements of the group differed significantly from those of a senior obstetrician and the course training had no impact on the variability. Similar studies should evaluate measurement variability in the light of pregnancy outcome.

The effect of practical training in obstetrics among medical students: symphysis-fundal height measurements.

In a study to evaluate the repeatability of symphysis-fundal (SF) height measurements by medical students, and the effect of practical training in obstetrics on this repeatability eight medical students and an obstetrician initially measured the SF height three times each in six pregnant women. The students were then split into two groups: a training group and a control group. After a training period at the University Hospital in Trondheim, another series of measurements were taken on another group of pregnant women. For comparison of results analysis of variance was used. Within and between observer variation are presented, and the results showed that the practical training had a positive effect on the repeatability of SF height measurements.