Lack of effects of polychlorinated biphenyls on testosterone synthesis in mice

Male mice were exposed to two different preparations of PCBs. The pure congener 2,2',4,4',5,5'-hexachlorobiphenyl (6-CB) was given at daily doses of 4, 20, and 40 mg/kg b.wt. during the perinatal or pubertal period. A technical mixture of PCB (Clophen A50) was administered during puberty at daily doses of 8, 40, 80, 120, and 160 mg/kg b.wt. Treatments were, in the different experiments, carried out every second or third day for three to five weeks. Treatment during puberty was started when the mice were 5 weeks old. The perinatal exposure was started on day 13 of gestation and ended on day 24 post partum. There were no significant differences in the plasma levels of testosterone between the treated mice and the controls after any of the treatments, but there was an increase in the relative testes weights for the animals treated perinatally. No influence on the biosynthesis of testosterone in the testicular interstitial cells in vitro could be demonstrated.     

Guidance of dopaminergic neuritic growth by immature astrocytes in organotypic cultures of rat fetal ventral mesencephalon.

Astrocytes, with their many functions in producing and controlling the environment in the brain, are of great interest when it comes to studying regeneration after injury and neurodegenerative diseases such as in grafting in Parkinson's disease. This study was performed to investigate astrocytic guidance of growth derived from dopaminergic neurons using organotypic cultures of rat fetal ventral mesencephalon. Primary cultures were studied at different time points starting from 3 days up to 28 days. Cultures were treated with either interleukin-1 beta (IL-1 beta), which has stimulating effects on astrocytic proliferation, or the astrocytic inhibitor cytosine arabinoside (Ara-C). Tyrosine hydroxylase (TH)-immunohistochemistry was used to visualize dopaminergic neurons, and antibodies against glial fibrillary acidic protein (GFAP) and S100 beta were used to label astrocytes. The results revealed that a robust TH-positive nerve fiber production was seen already at 3 days in vitro. These neurites had disappeared by 5 days. This early nerve fiber outgrowth was not guided by direct interactions with glial cells. Later, at 7 days in vitro, a second wave of TH-positive neuritic outgrowth was clearly observed. GFAP-positive astrocytic processes guided these neurites. TH-positive neurites arborized overlying S100 beta-positive astrocytes in an area distal to the GFAP-positive astrocytic processes. Treatment with IL-1 beta resulted in an increased area of TH-positive nerve fiber network. In cultures treated with Ara-C, neither astrocytes nor outgrowth of dopaminergic neurites were observed. In conclusion, this study shows that astrocytes play a major role in long-term dopaminergic outgrowth, both in axonal elongation and branching of neurites. The long-term nerve fiber growth is preceded by an early transient outgrowth of dopamine neurites.     

Effects of Hypothermia on Blood Endogenous Endotoxin Levels During Cardiopulmonary Bypass

A bstract Endotoxin activates white blood cells and complement and produces a spectrum of clinical syndromes ranging from fever to septic shock. Although production of endogenous endotoxemia during cardiopulmonary bypass (CPB) has recently been reported, the role of hypothermia on endotoxemia is not clear. In this study, we evaluated the effects of moderate (24–28°C) and mild (32–34°C) hypothermia on blood endotoxin levels. The study population consisted of 20 patients who underwent coronary artery bypass grafting (CABG) with CPB. Moderate systemic hypothermia was applied during aortic cross-clamping in ten patients (group 1) and mild hypothermia in the remaining ten patients (group 2). The mean rectal temperatures were 26.8 ± 1.2°C in group 1 and 33.8 ± 0.8°C in group 2. The blood samples for endotoxin level measurements were obtained before CPB, during aortic cross-clamping, immediately after the release of the cross-clamp, 20 minutes after the release of the cross-clamp, after CPB, and 2 hours postoperatively. There were no endotoxins in any of the samples before CPB, but it was detected after CPB in both groups. The endotoxin levels were significantly higher in group 1 than in group 2. The present study suggests that when hypothermia is the technique of choice, the deleterious effects of endotoxemia on patients with comorbidity must be considered.     

Contrasting subjective judgement and objective tests in the hearing-impaired.

The Hearing Performance Inventory (HPI, Giolas et al., 1979) was used to measure 21 moderately hearing-impaired persons' subjectively experienced problems in everyday listening. The HPI rating data show that the greatest problems are experienced on the dimensions 'understanding speech without visual cues', and 'perceived intensity' of sounds. 'Understanding speech with visual cues' has a high positive correlation with both 'social situation' and 'work situation' dimensions, whereas 'understanding speech without visual cues' correlates with 'social' and 'personal situation'. The correlations between the HPI and actual performance in the speechreading tests, and between the HPI and cognitive abilities that were assumed to be critical for speechreading ability, were also examined. It was found that vocabulary size, highly intercorrelated with guessing, was important to the 'social situation' dimension on the HPI. Guessing also constitutes an important cognitive predictor of speechreading skill. However, none of the HPI dimensions was directly related to objective communicative competence. Given the limitations of speechreading training, the data suggest that vocabulary and social skills should be focused on during communicative training.     

Effects of Epostane on progesterone synthesis in early human pregnancy

Healthy women requiring abortion in early normal pregnancy were recruited to study the abortifacient effects of different doses of Epostane, an inhibitor of 3 beta-hydroxy steroid dehydrogenase, that previously has been shown to interfere with progesterone production in the luteal phase of humans and to have abortifacient effects in animals. A single dose of 100 mg resulted in decreasing progesterone and estradiol, which rapidly recovered, and none of the women started to bleed. Repeated doses of 50 or 100 mg during one day resulted in a more pronounced decrease in both progesterone and estradiol, but no bleeding. When treatment was prolonged over several days with 100 mg X 4 for five days and 400 mg X 2 for four days, respectively, a suppression of progesterone and estradiol was found and two out of four and eight out of ten women started to bleed and subsequently aborted. The treatment was well tolerated by most of the women. Routine laboratory parameters remained unaltered throughout treatment. Cortisol levels remained within the normal range.     

Stabilization and quantitative determination of disulfiram in human plasma samples

The rapid reduction of disulfiram at therapeutic plasma concentrations was inhibited by addition of the chelating agent, diethylenetriamine pentaacetic acid, and acidification in the presence of sodium chloride. The disulfiram recovery at concentrations ranging from 0.100-0.800 mumol/l was about 100% when preserved at 4 degrees C and analyzed immediately, and 95% and 75% after preservation for 1 h at 4 degrees C and for 24 h at -20 degrees C, respectively. The concentrations of disulfiram were determined in plasma from alcoholics receiving repeated therapeutic doses of disulfiram. Detectable concentrations in the range of 0.100-0.200 mumol/l could not be obtained until the second week of treatment.     

Effect of continuous postoperative epidural analgesia on intestinal motility

The effect of postoperative epidural bupivacaine on intestinal motility was studied by measuring the transit time of barium contrast through the intestines in 16 patients after resection of the left colon and/or rectum. Fourteen patients served as controls and received postoperative injections of pentazocine. Mean transit time through the intestinal tract was 35 h in the epidural group and 150 h in the control group, a difference that is significant at the 0.1 per cent level. The average time before passage of flatus and faeces was different between the two groups at the 0.1 per cent level. We conclude that postoperative epidural bupivacaine constitutes an effective means of analgesia after colorectal surgery and is associated with a short duration of intestinal paralysis.     

Twenty-four-hour patterns of pineal melatonin and pituitary and plasma prolactin in male rats under 'natural' and artificial lighting conditions

Natural lighting differs from usual artificial lighting mainly as follows: it has larger spectral composition, fluctuations of intensity during the day, higher intensity levels during the night (moonlight, starlight), and gradual changes of illuminance at dawn and dusk. The present experiment was performed in order to study whether these features of lighting affect the 24-hour patterns of melatonin and prolactin in male rats. The rats were kept 7 days in 'natural' lighting (sunlight through windows) or in artificial lighting (cool white fluorescent lamps) of similar periodicities (13/11 h light/dark). The samples were collected at 3-hour intervals during a 24-hour period. Pineal melatonin contents, pituitary prolactin contents, and plasma prolactin concentrations were measured radioimmunologically. The nocturnal pineal melatonin contents were higher and the daytime contents lower in natural than in artificial lighting conditions. A corresponding 'strengthening of rhythm' of prolactin was found in natural lighting. A reason for the higher amplitude variation of melatonin in the natural lighting conditions may be the gradual changes of illuminance at dawn and dusk. The different pituitary and plasma prolactin patterns of the rats kept in the two lighting conditions might partly be explained by a stimulatory effect of melatonin on the production and secretion of prolactin, but other regulatory factors had to be involved, too.