Effect of Calcitonin on the Alcohol Drinking of Rats

Previous work has shown that calcitonin inhibits eating by rats and that it affects several neurotransmitter systems suspected to play a role in alcohol consumption. The present study was an initial test of whether calcitonin does affect voluntary alcohol consumption by male Wistar rats with prolonged alcohol experience. Calcitonin (20 IU/kg) or saline was injected subcutaneously on 10 consecutive days when the rats (n = 20) had continual access to 10% (v/v) ethanol solution, and to food and water. Using a cross-over design, the effects of 40 IU/kg calcitonin vs. saline were then examined in a second 10-day treatment period. Similar patterns of effects were obtained with both calcitonin doses, but the patterns differed with alcohol, food, and water intake. Alcohol drinking showed biphasic changes with both doses, producing highly significant Treatment x Day interactions (p < 1E-10 and p = 6E-7): it was significantly reduced on the first day of calcitonin treatment and significantly increased on the last few days. Food intake was reduced on all calcitonin days although most markedly on the first. Water drinking was not altered on the first calcitonin day, but was greatly increased on the second, then gradually returned toward the baseline. In a second experiment, the animals were switched to 1 hr of alcohol access per day, and calcitonin (20 IU/kg) was administered periodically to one group 4 hr before the alcohol access. Alcohol drinking was significantly reduced in all cases when the calcitonin injection was preceded by at least 1 day without calcitonin.(ABSTRACT TRUNCATED AT 250 WORDS)     

Biologic significance of surface microroughing in bone incorporation of porous bioactive glass implants

A novel chemical etching method was recently developed to create a controlled microrough surface on porous bioactive glass implants. Our earlier in vitro studies showed enhanced attachment of osteoblast-like MG63 cells on a microrough bioactive glass surface. The purpose of our current study was to confirm the in vivo significance of surface microroughening for bone bonding of bioactive glass. Porous bioactive glass cones made of sintered microspheres were surgically implanted in the anterior cortex of rabbit femurs. Peripheral quantitative computed tomography (pQCT), biomechanical push-out testing, histomorphometry, and electron microscopy (BEI-SEM) were used to analyze bone ingrowth and osseointegration at 7, 10, 14, 28, 56, and 84 days after implantation. The results showed that microroughening of the bioactive glass surface significantly enhanced the bone-bonding response of the biomaterial. The positive response was seen in one of the three bioactive glass compositions studied. The affinity index of new bone on the glass surface was significantly (p = 0.02) increased with a trend (p = 0.10) toward improved mechanical incorporation. New bone formation was dependent on the glass composition, and it was found to occur not only through the mechanism of bone ingrowth but also based on in situ osteogenesis within implant interstices. Based on these results, the procedure of microroughening could enhance the osteopromotive properties of certain bioactive glass compositions.     

Localization of the human SH-protease inhibitor in the epidermis. Immunofluorescent studies.

Human epidermis contains a low molecular weight SH-protease inhibitor (Human Epidermal Inhibitor = HEI), whose epidermal localization was performed with the indirect immunofluorescence method. The fluorescence was most intensive in the cytoplasms of epidermal cells, often occurring perinuclearly. The fluorescent material in the frozen sections was often finely granular and occasionally extended outside the cytoplasm, while the fluorescence in fixed sections was more uniform, but weaker. Stratum basale generally stained poorly or not at all, as did also stratum lucidum. Stratum corneum stained fairly intensively throughout. In addition to fixation, the outcome of staining was also affected by the thickness of the epidermis, particularly stratum corneum. The significance of this inhibitor for the differentiation of epidermal cells and the keratinization of epidermis has therefore been discussed, and the authors assume it to be of considerable significance in these processes.     

Sleep-wake rhythm in an irregular shift system

Sleep in shift work has been studied extensively in regular shift systems but to a lesser degree in irregular shifts. Our main aim was to examine the sleep-wake rhythm in shift combinations ending with the night or the morning shift in two irregular shift systems. Three weeks' sleep/work shift diary data, collected from 126 randomly selected train drivers and 104 traffic controllers, were used in statistical analyses including a linear mixed model and a generalized linear model for repeated measurements. The results showed that the sleep-wake rhythm was significantly affected by the shift combinations. The main sleep period before the first night shift shortened by about 2 h when the morning shift immediately preceded the night shift as compared with the combination containing at least 36 h of free time before the night shift (reference combination). The main sleep period before the night shift was most curtailed between two night shifts, on average by 2.9 and 3.5 h among the drivers and the controllers, respectively, as compared with the reference combination. Afternoon napping increased when the morning or the day shift immediately preceded the night shift, the odds being 4.35-4.84 in comparison with the reference combination. The main sleep period before the morning shift became 0.5 h shorter when the evening shift preceded the morning shift in comparison with the sleep period after a free day. The risk for dozing off during the shift was associated only with the shift length, increasing by 17 and 35% for each working hour in the morning and the night shift, respectively. The results demonstrate advantageous and disadvantageous shift combinations in relation to sleep and make it possible to improve the ergonomy of irregular shift systems.     

Decreased inducibility of TNF expression in lipid-loaded macrophages

Background  

Inflammation and immune responses are considered to be very important in the pathogenesis of atherosclerosis. Lipid accumulation in macrophages of the arterial intima is a characteristic feature of atherosclerosis which can influence the inflammatory potential of macrophages. We studied the effects of lipid loading on the regulation of TNF expression in human monocyte-derived macrophages.     

The Effect of Small Variation of the Frequent Auditory Stimulus on the Event-Related Brain Potential to the Infrequent Stimulus

We investigated whether the mismatch process between a rare stimulus and the trace of frequent stimulus, which generates the mismatch-negativity component of the event-related potential, can tolerate a small variation in the intensity of the frequent stimulus. Series of short tone pips were presented to 10 subjects while they were reading a book and ignoring the auditory stimuli. The intensity (mean 80dB) of the frequent stimulus (600 Hz) varied within a range that was different in different blocks. The probability of the infrequent stimuli which were, in different blocks, either intensity deviants (600 Hz/70dB) or frequency deviants (650 Hz/80dB) was 10%. Both deviant stimuli elicited mismatch negativity even when the intensity of the frequent stimulus varied, although the amplitude of this component decreased with the increasing variability of the frequent stimulus. These results show that the generator process of mismatch negativity tolerates some variation in the repetitive stimulus, thus indicating that this process is also activated in ecologically more valid conditions. This is crucial to the interpretation of the generator process of mismatch negativity as a biologically vital warning mechanism.     

Studies in kidney tubulogenesis

Summary The formation of secretory tubules in the embryonic mouse metanephrogenic mesenchyme in vitro has been produced with embryonic spinal cord serving as inductor. The activity of NADH-tetrazolium reductase, acid phosphatase, thiamine pyrophosphatase and ATP-ase activities was assayed cytochemically on frozen sections of cold-formalin fixed explants.What was apparently the first phase of differentiation of kidney tubules became evident in the form of cell condensations. These were accompanied by an increased NADH-tetrazolium reductase activity, suggesting the maturation of both mitochondria (particulate reaction product) and endoplasmic reticulum (homogeneous staining). Furthermore, in the young explants there were visible areas of distinct enzyme activity, with no histological characteristics of the cell condensations. It was considered that these probably represented the earliest phase of differentiation detected by microscopic technique. Thiamine pyrophosphatase activity appeared in the Golgi apparatus of the cells during their organization into tubular epithelium and the formation of lumen. A subsequent increase in acid phosphatase activity of the cytoplasm was noticed. All of the active cytoplasmic organelles, marked by the enzyme activity cytochemically demonstrable, were moved to the apical side of the tubule cells in the course of their cytodifferentiation. After seven days of cultivation, the ATP-ase activity appeared first both in the cell membranes and in the cytoplasm of the tubule cells. At this phase of development, the kidney tubules induced in vitro thus displayed many of the cytochemical characteristics known to exist in the secretory tubules of the mature kidney.Supported by grant from the Sigrid Jusélius Foundation, by grant from Finnish Medical Research Council and by grant C-5347 from the National Cancer Institute, National Institutes of Health, Public Health Service to Prof. Toivonen and Dr. Saxén.