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.     

The meaning of work after acquired brain injury.

PURPOSE: Research in the field of brain injury rehabilitation has tended to regard return to work as a measure of outcome. Researchers have not paid particular attention to the experiences of people living with a brain injury. The aim of the phenomenological study reported here was to identify and describe what characterizes the meaning of work to those with acquired brain injury. METHODS: Ten participants of working age were interviewed about the meaning of work 1-5 years after being inflicted with a brain injury. Data were analyzed and interpreted using the Empirical Phenomenological Psychological method. RESULTS: The findings revealed a meaning structure consisting of four main characteristics. Work was no longer experienced as the primary event in life and the social dimension had become more important. The perceived competence and work identity were threatened after the injury. A common theme across all interviews was the struggle to return to a state of normality, and working was considered to be evidence of success. CONCLUSION: The findings described the altered meaning of work 1-5 years after brain injury. This knowledge should lead to an increased understanding among occupational therapists engaged in work rehabilitation after brain injury and can serve as a basis for individualized intervention strategies.     

Epidemiology and etiology of bladder cancer.

Urinary bladder cancer has long been associated with specific etiologic factors, and our knowledge of these factors has increased during this century. The most important factor, even in industrialized societies, is cigarette smoking. Specific chemicals have also been identified as causing bladder cancer, as have a variety of occupational exposures to less well-defined specific agents. In other parts of the world, the association of bladder cancer with Balkan nephropathy, endemic blackfoot disease, and schistosomiasis provides additional leads for investigating, and potentially preventing, the process of carcinogenesis in humans. Many of the critical observations in our understanding of bladder cancer have been made by practicing physicians, and this is likely to continue. It is essential that physicians dealing with bladder cancer patients be attuned to potential etiologic factors, including cigarette smoking, various industrial exposures, or drug exposures to further our understanding of this issue. Bladder cancer is a potentially preventable disease and an important one, as indicated by the total number of cases and the extent of morbidity and death attributable to it around the world.     

Evaluation of regret after tubal sterilization.

Many different criteria and profiles have been suggested for the possible cause of regret and requests for reversal after tubal sterilization. Evaluation of data obtained from 2253 women who had undergone tubal sterilization showed a strong correlation between regrets and youthful age and to changes in marital situation. Previously demonstrated risk factors, such as sterilization in connection with abortion or labor were not related to regret in this study material.