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Biomedical subjects

B Stahl

Publications and source records attributed to B Stahl.

At least 73 records · Page 4Linked to original sources
PubMed1992

Pit and fissure sealing and mutans streptococci levels in saliva.

The effect of preventive pit and fissure sealants with a resin-based material on the number of salivary mutans streptococci was evaluated in 46 healthy 12-year-old school children (F group) with medium or high counts during a 1-year study period. As controls served 33 children of the same age with the same bacterial levels at baseline (C group) and 55 children with low levels (L group). Caries prevalence and incidence were registered clinically and radiographically. Sealing of all accessible pit and fissures was carried out in the F group with a light-cured Bis-GMA sealant. Bacterial levels at baseline and 3, 6, 12 and 52 weeks after treatment were estimated with a chairside method. The results disclosed a significant (P < 0.05) drop in the number of salivary mutans streptococci in the F and C groups at all sampling occasions compared to baseline. There were however no differences between the groups during the study period. Both the caries prevalence and incidence were significantly (P < 0.05) higher in F and C groups when compared to the L group. The results suggest that preventive pit and fissure sealing with a resin based material does not affect salivary mutans streptococci levels.

Child↗
PubMed1990

Effects of reversible nare occlusion on the development of the olfactory epithelium in the rabbit nasal septum.

To investigate environmental influences on the development of the olfactory epithelium, semi-thin sections were taken from the nasal septum of newborn and 30-day-old rabbits; the epithelial thickness and the number of olfactory knobs, supporting cells, dark basal cells, and receptor cells were compared. During normal development, a marked increase in epithelial thickness was found, largely because of an increase in the number of receptor cells. Whereas unilateral nare occlusion on day 1 resulted in 10% fewer receptor cells and 25% fewer knobs on the deprived side by day 30, nare occlusion either up to or after day 5 had little effect, and even temporary reopening from days 6-7 was sufficient to stimulate receptor-cell development on the occluded side. Although in these latter cases, a slight deprivation effect of 6% was still found in the number of receptor-cell nuclei, there was no longer a significant difference in the number of knobs between the open and closed sides. Thus, whereas exposure to the environment during the first days of life appears to be sufficient to stimulate sustained growth, the deprived epithelium may retain the capacity to respond to such cues beyond this time. However, as nare occlusion also had an effect on the respiratory epithelium and nasal lymphatic tissue, the nature of the cues stimulating receptor-cell development, whether olfactory or non-olfactory, is not yet clear.

Afferent Pathways↗
PubMed1990

Biochemical characterization of a putative axonal guidance molecule of the chick visual system.

Temporal retinal axons growing in vitro on carpets of tectal membranes are deflected by cell membranes of posterior tectum. The activity responsible for this deflection can be abolished by antibodies raised against tectal membranes and the corresponding Fab fragments. Analysis of tectal membranes by two-dimensional gel electrophoresis and immunoblotting reveals a 33 kd glycoprotein that has a higher concentration in posterior than in anterior tectum. Its expression is developmentally regulated, and it is sensitive to phosphatidylinositol-specific phospholipase C. These are properties expected for a molecule responsible for the phenomena observed in experiments on in vitro guidance of retinal axons.

Animals↗
PubMed1990

In vitro experiments on axonal guidance and growth-cone collapse.

In the retinotectal projection, nasal retinal axons project to posterior tectum, while temporal axons project to the anterior part of the tectum. In in vitro experiments, a similar specificity can be observed: the nasal and temporal retinal axons can be guided by tectal membrane components so that, for example, temporal retinal axons, when growing on a striped substratum consisting of anterior and posterior tectal membranes, express a very strong preference for the anterior stripes. This preference is not due to attractivity of anterior membranes but rather to avoidance of posterior material, although the pure posterior membranes are a very good substratum for growth of temporal axons. The repellent guidance molecule has been identified. Interestingly, besides guidance this molecule causes another reaction: when growing temporal axons are exposed to medium containing either posterior membranes or artificial lipid vesicles containing the repellent guidance molecule, the axonal growth cones collapse. As in guidance, there is a clear regional specificity: e.g. the repellent guidance molecule derived from posterior tectum induces collapse of temporal but not of nasal axons. Since the guiding and the collapse-inducing activity are expressed by one and the same glycoprotein molecule (Mr 33 x 10(3), linked to the membrane by phosphatidylinositol) and since another molecule has been identified by Keynes' group which also expresses both guiding and collapse-inducing activity, one might speculate that axonal guidance and axonal collapse have something in common. Models of axonal guidance will be discussed.

Animals↗
PubMed1989

Induction of esophageal injuries by doxycycline and other pills. A frequent but preventable occurrence.

Many specialists and general physicians remain unaware of the potential for and pathogenesis of drug-induced esophageal ulcerations. To promote a greater awareness of the importance of this problem, we have reviewed the literature, particularly in regard to the mechanisms of action and the clinical and therapeutic implications of these chemical injuries to the esophagus. There can be no doubt that the frequency of occurrence of drug-induced esophageal ulceration far exceeds that reflected in the reported cases appearing in the medical literature. Nor can we deny that much of the responsibility for this situation lies in the failure of the prescribing physician to educate his patients (and himself!) in the art of taking potentially harmful pills and capsules, particularly tetracycline, doxycycline, potassium chloride, and quinidine preparations. Although most such drug injuries are self-limited events, there have been a number of fatalities reported and at the very least they involve acute discomfort.

Capsules↗
PubMed1989

Characteristics of sorbitol uptake in rat glial primary cultures.

Uptake of [U-14C]sorbitol was studied in astrogliarich rat primary cultures. Initial rate of sorbitol uptake is proportional to sorbitol concentration between 20 microM and 400 mM. Sorbitol transport is not inhibited by glucose, fructose, and a variety of structurally related polyols, or by cytochalasin B, an inhibitor of glucose transport. Phloretin, phlorizin, filipin, and n-hexanol, all compounds that alter the properties of biological membranes, and the sulfhydryl reagent p-chloromercuribenzoate inhibit sorbitol uptake to various degrees. Variation in the concentrations of extracellular Na+ and K+ does not affect transfer of sorbitol across the cell membrane. It is concluded that sorbitol is taken up into glial cells by a diffusion process, not involving a carrier and probably not through the lipid bilayer, but through a proteinaceous channel-like structure.

Animals↗
PubMed1987

The appearance of macrophage migration-inhibition factor in drug reactions.

Drug-induced adverse reactions were suspected in 2030 patients with known exposure to 243 different drugs. A modified direct macrophage migration-inhibition factor (MIF) test for the different drugs was carried out on blood samples from these patients. There was a positive MIF response toward one or more of the suspected drugs in 53.4% of the patients as compared to 4.9% of the control group; 155 of the 243 drugs elicited a positive MIF response. The percentage of positive responses for each particular drug was not related to the number of patients tested, reflecting the variability in specific immunogenicity of the different drugs. The high percentage of positive MIF reactions in relation to the clinical diagnosis suggests that this test can be a useful aid in the detection of the offending drug in cases of suspected drug-induced reactions.

Animals↗
PubMed1985

Carbamazepine-induced hair loss.

An 8 1/2-year-old girl was treated with carbamazepine because of headaches and electroencephalogram findings compatible with multifocal epilepsy. Within a week of drug initiation, hair shedding started. This continued until the drug was stopped, when new hair growth resumed. The hair loss was associated with carbamazepine serum concentrations lower than the therapeutic range.

Alopecia↗
PubMed1985

Effects of television modeling on residential energy conservation.

A combination of social marketing, communications, social learning (particularly modeling), and behavior analysis may provide an effective framework for behavior change via films and television. We used this approach in developing special television programs about residential energy conservation. The programs were tailored and directed to preselected middle-class homeowners (N = 150), and delivered over a public access channel of a cable TV system. The results indicated that after one program exposure (about 20 minutes), viewers adopted simple strategies modeled in the programs which led to savings of approximately 10% on their home energy use for a substantial part of the cooling and heating season. Although the potential benefits to costs of large-scale media efforts seemed great, institutional barriers for such programs were identified. Less expensive, more local programs seem more viable.

Journal Article↗
PubMed1984

[Anti-anginal efficacy of oral nitroglycerin. A clinical double-blind study with dose-effect relationships].

Nitroglycerin, bound to polymerized cellulose (Nitroglin) was administered orally in single doses of 2.6 mg, 6.5 mg, 10 mg and 20 mg (randomized sequence) on four different days to 12 patients with angina due to coronary heart disease. This was done within the framework of a placebo-controlled double-blind study with intra-individual cross-over to assess dose-related reduction of the ischaemia reaction in the exercise ECG. The ischaemia reaction (sum of ST segment depressions) 30 min after a placebo was 10.4 +/- 4.6 mm; after 2.6 mg nitroglycerin it was 8.0 +/- 4.3 mm (-23%, not significant); after 6.5 mg it was 6.4 +/- 3.4 mm (-38%, P less than 0.01), after 10 mg it was 4.7 +/- 2.9 mm (-55%, P less than 0.001), and after 20 mg 2.7 +/- 1.9 mm (-74%, P less than 0.0001). The dose-related effect of nitroglycerin was still demonstrable to the same extent three hours after intake. After 20 mg a reduction in ischaemia reaction by 55% compared with the placebo effect was still present 6 hours later (P less than 0.01). The arterial blood pressure on lying and standing as well as the heart rate on lying, standing and on exercise did not change significantly, regardless of dose. Taken by mouth nitroglycerin was well tolerated and had a dose-related anti-anginal effect. After single doses of 10-20 mg the anti-ischaemic effect was shown to persist for several hours.

Administration, Oral↗
PubMed1984

Dose-response relation of antianginal activity of isosorbide dinitrate.

Eleven men with angiographic evidence of coronary heart disease and stable, exercise-induced angina pectoris were given placebo (P) or isosorbide dinitrate (ISDN) in a daily dose of 30, 120, 240 or 480 mg, in a randomized single-blind trial. The daily doses were administered 6 times a day as single oral doses of 5, 20, 40 and 80 mg. Each dose or placebo was given for 7 days. Before therapy was begun, and on the seventh day of each treatment period, an exercise ECG with standardized level and duration of exercise was recorded. Subsequently, a 4-week treatment period with 480 mg/day was carried out at the end of which another stress test was performed. The was followed by a final 2-week placebo period. The frequency of anginal attacks per week tended to decrease with increasing nitrate doses, but decreased significantly only after the highest dose (480 mg/day) compared with placebo. Continuation of therapy with 480 mg/day maintained the reduced rate of anginal attacks. The ischemic response, expressed as the sum of ST-segment depressions in the exercise ECG, revealed a dose-dependent reduction of 26% (30 mg/day), 39% (120 mg/day) (p less than 0.01), 63% (240 mg/day) (p less than 0.01) and 72% (480 mg/day) (p less than 0.01), respectively. At the end of the 4-week treatment period with 480 mg/day, antianginal efficacy was found to be moderately reduced, showing a 56% reduction of ischemic response compared to the placebo trial. The time of onset of angina during exercise testing was also delayed in relation to the dosage given.(ABSTRACT TRUNCATED AT 250 WORDS)

Angina Pectoris↗
PubMed1984

Differences in the production of methemoglobin during high-dose treatment with isosorbide dinitrate or isosorbide 5-mononitrate.

12 patients with coronary heart disease were studied to see whether high doses of isosorbide dinitrate (ISDN, Corovliss) or isosorbide 5-mononitrate (IS-5-MN, Ismo) increase the erythrocyte methemoglobin production in an acute experiment and after 4 days of medication. The patients were divided into two groups. Group 1 (6 patients) was given a single dose of 80 mg ISDN on the morning of day 1 and Group 2 (6 patients) was given 80 mg IS-5-MN as a single oral dose. Under the influence of the IS-5-MN no change was observed from the initial methemoglobin (met-Hb) value (0.81% of the total Hb) at measurements performed 1 and 2 h after the administration of the drug. In Group 1 (ISDN) the initial met-Hb value was 0.58% of the total Hb, a slight increase to 0.70% being observed after 1 h and to 0.77% after 2 h (p less than 0.05). The patients were then treated as follows for a further 4 days: Group 1 480 mg ISDN/d, Group 2 480 mg IS-5-MN/d. On day 5 the initial met-Hb values in both groups were unchanged compared to day 1. The patients were then given first 80 mg ISDN (Group 1) or 80 mg IS-5-MN (Group 2) and 4 h later a single dose of 160 mg of the appropriate substance. In Group 2 (IS-5-MN) the met-Hb content remained unaffected. In Group 1 a slight increase of the met-Hb to 0.79% occurred 1 h after 80 mg ISDN and to 0.9% after 2 h (p less than 0.05). The dose of 160 mg ISDN gave rise to a further slight increase to 1.00% (after 1 h) and 1.13% (after 2 h) (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1983

[Medico-psychological base and trend documentation in a residential facility for rehabilitation of the handicapped].

The article presents the system for medical-psychological base and trend documentation developed between 1977 and 1980 at Rotenburger Anstalten der Inneren Mission (Home Mission). A practicable system from the user angle, it is operated on a mediumsized data processing unit. Being a pure dialogue system with programme generators, it is easy to handle and flexible in its possible applications, several of which are illustrated by examples from the rehabilitative field. As the various characteristics used can easily be attributed with other contents, and as the data base can moreover be expanded, the documentation system could also be used by comparable facilities that have the necessary electronic data processing equipment at their disposal.

Computers↗