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Biomedical subjects

M Steiner

Publications and source records attributed to M Steiner.

At least 271 records · Page 15Linked to original sources
PubMed1990

Analysis and processing of data in a hospital-based diabetes management system.

Both short-term care (blood glucose monitoring) and long-term care (clinical examinations) of diabetes generate an ample amount of data for each patient. Health care in hospitals has to provide services with respect to both demands. The quality of control depends on obtaining the right finding at the right time and taking the individually adequate measures. These repetitive activities follow to a certain extent standardized algorithms and computer-programs are able to support demands like this; however, up to now no attempts have been made to provide useful tools for this environment. DIALIN is a data-bank especially designed for the use in hospitals or outclinics and Camit is a diabetes management system for advanced evaluation of long-term blood glucose monitoring data. The expert-system DIACONS up to now determines diabetes type and adequate initial therapy from data of patients' history alone; it operates on the DIALIN-databank via SQL. DIALIN has proven to be a useful tool for data-processing in hospitals. Camit was well accepted by patients in a feasibility study. DIACONS has been tested with 83 diabetic patients to provide the correct diabetes-type and the proper initial regimen with a precision of 96% compared to the correspondence between two independent experts. The combination of all three systems is a step towards the Munich Medical Information system MAMIS.

Blood Glucose Self-Monitoring↗
PubMed1990

[Caries prevalence in Zurich schoolchildren in 1970, 1983 and 1988].

In 1988, a random sample of 657 school children of the City of Zurich was examined for dental caries using standardized methods. The children at age 12 and 14 had 2.36 and 4.24 DMFT, respectively. There was a decline of caries prevalence during the period 1983-1988. Compared with the earliest available data obtained in 1958 and 1961, the children of 1988 had 69 to 78% less DMFT, and 54 to 60% when compared with the data obtained in 1970.

Adolescent↗
PubMed1990

The clinical spectrum of infections with viridans streptococci in bone marrow transplant patients.

A retrospective review of 832 bone marrow transplant patients was performed to determine the clinical spectrum and risk factors for viridans streptococci infections. The incidence of viridans streptococci cultured from the blood and/or cerebrospinal fluid was 15% (123/832), occurring within 15 days of bone marrow transplant in 78% of patients, usually during profound neutropenia. Strep. mitis was the most frequent isolate (47%). Only 27% (33/123) of patients were symptomatic beyond fever, usually with neurologic, pulmonary, and/or cardiovascular manifestations. Ten (8%) of 123 culture positive patients developed a fulminant cardiorespiratory collapse, with a 60% mortality. One additional death occurred due to cerebritis. However, a time dependent covariate analysis found no significant difference in overall mortality (p = 0.30) or duration of hospitalization (p = 0.50) in patients with or without viridans streptococci infections. A multivariate analysis revealed that age less than 18 years (RR = 1.5, p = 0.04) and a primary diagnosis of acute lymphocytic leukemia (RR = 1.5, p = 0.07) were independent and significant risk factors for viridans streptococci infections. Sex, conditioning regimen, donor type, in vitro bone marrow treatment, and acute graft-versus-host disease were not significant. Viridans streptococci should be recognized as pathogens in bone marrow transplant patients which require appropriate antibiotics and aggressive supportive therapy.

Bone Marrow Transplantation↗
PubMed1990

[Will discolored molar fissures within 4 years become carious more frequently than nondiscolored ones? Observations from 1975 to 1988].

Caries progression was studied in 5242 first molar fissures of children in the Canton of Zurich, Switzerland, in two observation periods, extending from 1975/76 to 1979/80 and from 1983/84 to 1987/88, respectively. DFT averages at age 12 in the children studied were fairly low, being 3.60 in 1975/76 and 2.21 in 1983/84. Fissures of first molars were classified as completely sound (Grade 0), discolored (Grades 1 and 2) or DF. An exploratory cross-sectional analysis revealed that there is a slow and linear increase of the percentage of DF fissures with increasing age. During the period 1975/76 to 1979/80, Grade 0 fissures became DF with a probability of 14 to 22% while 42 to 54% of the dark brown or black discolored fissures (Grade 2) were DF after four years. In the period 1983/84 to 1987/88, these percentages were lower. It was concluded that in this population with low caries activity there is little reason to apply preventive measures to fissures immediately after their eruption or later to those free from any discoloration.

Child↗
PubMed1989

Novel localizations of central- and peripheral-type cholecystokinin binding sites in Syrian hamster brain as determined by autoradiography.

Neuronal cholecystokinin (CCK) binding sites were studied in the Syrian hamster, a species with unique CNS localizations of CCK immunoreactivity. Preliminary studies of hamster forebrain sections using 125I-Bolton-Hunter-(BH)-CCK-8 indicated that radioligand binding kinetics and receptor selectivity for various unlabelled CCK peptides were similar to those reported for other species. Autoradiographic visualization of CCK binding sites revealed that the highest binding densities were distributed in the cerebral cortex, olfactory bulb, dorsal vagal complex, raphe obscurus and cochlear nuclei. Moderate binding densities were present in the amygdala, hippocampus, hypothalamus, thalamus, central grey and medial vestibular nucleus. Comparison of autoradiograms generated from adjacent sections incubated in 125I-BH-CCK-8 with unlabelled sulfated or desulfated CCK-8 confirmed the presence of peripheral-type CCK binding sites (i.e. at which desulfated CCK-8 has weak displacing activity) in the hamster dorsal vagal complex. Peripheral-type CCK binding sites were also distributed in regions of the hypothalamus (e.g. the magnocellular cell groups) where similar receptor selectivity had not been previously demonstrated. These observations provide further evidence of species differences in CCK receptor distribution and specificity, which may account for species differences in responsiveness to intracranial administration of CCK peptides.

Animals↗
PubMed1989

Undifferentiated (embryonal) sarcoma of the liver. A clinicopathologic study of a survivor treated with combined technique therapy.

Undifferentiated (embryonal) sarcoma is one of the less common primary malignant tumors of the liver that typically, although not exclusively, presents in later childhood. It has come to be recognized as an aggressive neoplasm with the potential for local recurrence and distant metastasis, despite a seemingly successful total surgical resection. This report documents our experience with an 8-year-old boy who had an 80% hepatectomy for an undifferentiated (embryonal) sarcoma, followed by cisplatin (90 mg/m2), doxorubicin (20 mg/m2/d), and radiation therapy (1950 cGy) to the tumor bed. Residual microscopic tumor was very likely present in the region of the inferior vena cava, but exploratory laparotomies for the purpose of "second-look" biopsies were performed with negative results after the completion of each course of chemotherapy. The patient is off of treatment and disease-free 30 months after the diagnosis. Because the survival at this time has been so poor for this highly malignant tumor, we suggest that the combination of therapeutic techniques and second-look laparotomy(s) to identify any subclinical tumor may be a reasonable approach. Ultrastructural and immunohistochemical studies by us and other investigators indicate that the neoplastic cells are primitive mesenchymal cells by electron microscopic study and have immunoreactivity limited to vimentin, alpha-1-antitrypsin, and alpha-1-antichymotrypsin.

Child↗
PubMed1989

Permeabilization of platelets: an investigation of biochemical, ultrastructural and functional aspects.

The biochemical, ultrastructural and functional aspects of digitonin-permeabilized platelets were investigated. Human platelets were permeabilized by exposure to the steroid glycoside digitonin. A 60 microM concentration of this permeabilizer produced a very substantial release of cytosolic enzymes from the platelets. Release from subcellular granules was relatively low and did not inhibit the response of platelets to a series of agonists. Although digitonin-permeabilized platelets required higher threshold concentrations of the usual stimulants, both primary and secondary aggregation as well as the release of nucleotides and enzymes from their respective granules remained intact. Transmission electron micrographs revealed discontinuities in the plasma membrane of digitonin-treated platelets, but scanning electron microscopy showed no difference between control and permeabilized platelets. No substantial loss of structural or membrane proteins could be detected by one- and two-dimensional gel electrophoresis. The pore size produced by digitonin treatment was sufficient to allow entry of 125I-labeled IgG into the platelet cytosolic space.

Adenine Nucleotides↗
PubMed1989

The role of microtubules in platelet secretory release.

The role of microtubules in platelet aggregation and secretion has been analyzed using platelets permeabilized with digitonin and monoclonal antibodies to alpha (DM1A) and beta (DM1B) subunits of tubulin. Permeabilized platelets were able to undergo aggregation and secretory release. However, threshold doses of agonists capable of eliciting a second wave of aggregation and the platelet release reaction were higher than in control platelets exposed to dimethyl sulfoxide, the solvent for digitonin. Both antibodies to alpha and beta tubulin caused a further increase in the threshold concentration of agonists and inhibited the secretory release of permeabilized platelets, but were ineffective using intact platelets. Neither monoclonal antibody inhibited polymerization or depolymerization of platelet tubulin in vitro. Antibodies to platelet actin and myosin also exhibited an inhibitory activity on platelet aggregation albeit less severe than that observed with the antibodies to alpha and beta tubulin. There was evidence of an interaction between DM1A and DM1B and the antibodies to actin and myosin. The interaction of platelet tubulin and myosin was investigated by two different methods. (1) Coprecipitation of the proteins at low ionic strength at which tubulin by itself did not precipitate and (2) affinity chromatography on columns of immobilized myosin. Tubulin freed of its associated proteins (MAPs) by phosphocellulose chromatography bound to myosin in a molar ratio which approached 2. Platelet actin competed with tubulin for 1 binding site on the myosin molecule. MAPs also reduced the binding stoichiometry of tubulin/myosin. Treatment of microtubule protein with p-chloromercuribenzoate or colchicine did not influence its binding to myosin. DM1A and DM1B inhibited the interaction of tubulin and myosin. This effect could also be demonstrated by reaction of electrophoretic transblots of extracted platelet tubulin with the respective proteins. We interpret these results as evidence for an interference of the two monoclonal antibodies to the tubulin subunits (DM1A and DM1B) with the translocation of microtubule protein from its submembranous site to a more central one during the activation process.

Actins↗
PubMed1989

[Prevalence of caries and fluorides].

In the whole of Switzerland, caries prevalence was high until 1960. Dental health education programs which included topical fluorides were introduced in the 1960's. Substantial declines of dental caries prevalence have been documented since 1968. In the canton of Zurich e.g. fourteen year-old children had an average of 23.8 cavities (most of them filled) in 1963 which was reduced to only 3.8 in 1987. Similar reductions, primarily due to multiple uses of fluorides, have also been obtained in younger age-groups and in other parts of Switzerland. On an epidemiological basis fluoridated salt reduced dental caries prevalence better than fluoride tablets. This is because tablets are only preferable for a minority of well-motivated families and required good compliance by the children. Modern research reveals that it is not the amount of ingested fluoride (acting systemically) but the frequency and duration of the contact of the fluoride with the erupted teeth which is most important. During pregnancy fluoride tablets benefit the mother's teeth and ensures a satisfactory fluoride level in the fetal skeleton. This is considered desirable as mothers' milk consistently contains only approximately 0.02 ppm fluoride. No caries-protective effect of the fetal fluoride, however, has been substantiated by pertinent research. Only a negligible cariostatic effect results by supplying fluoride to the infant. Caries prevention by fluoride begins to be important during the eruption of the primary teeth, at the latest at the eruption of the primary molars.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1989

Time resolved analysis of tubulin phosphorylation during platelet activation.

Tubulin phosphorylation was analyzed during the different phases of platelet activation. Platelets preloaded with [32P]-phosphate were stimulated with collagen. Tubulin was immunoprecipitated from serial samples obtained during the activation process. The immunoprecipitates were resolved by SDS-polyacrylamide gel electrophoresis and autoradiographs analyzed by laser densitometry. Agonist induced dephosphorylation of platelets occurred after the onset of shape change at the time of initiation of the secretory release. The dephosphorylation was selective affecting specific peptides.

Adenosine Triphosphate↗
PubMed1989

A study of breastfeeding and the return of menses and pregnancy in Karachi, Pakistan.

A longitudinal study of breastfeeding women was conducted to determine whether breastfeeding frequency is associated with the length of postpartum amenorrhea. The data are also conducive to testing the guidelines of the "Bellagio Consensus" (i.e., that there is no more than a 2% chance of pregnancy during breastfeeding in the first six months postpartum in the absence of vaginal bleeding and regular supplements). Twenty-eight breastfeeding women were followed-up weekly in Karachi, Pakistan. The frequency of breastfeeding was found to be a poor correlate of the duration of amenorrhea. Thirty-six percent of the women became pregnant during the study. However, all were having menses and/or giving regular supplements before the estimated date of conception, consistent with the Bellagio Consensus. In countries such as Pakistan, where contraceptive use is low, active promotion is needed to prevent the further decline of breastfeeding in order to retain its contraceptive as well as other maternal and child health benefits.

Adult↗
PubMed1989

Regional cerebral blood flow patterns in visual imagery.

Regional cerebral blood flow patterns were investigated by means of single photon emission computerized tomography in subjects who solved cognitive tasks which either did or did not require the use of visual imagery. In a first experiment judging the correctness of visual imagery sentences like "a grapefruit is bigger than an orange" led to increases of regional activity in inferior temporal and in the left inferior-occipital region when compared to blood flow patterns elicited by judgements about low imagery sentences or by responding differentially to "yes" and "no". Motor imagery sentences did not cause such an increase. In a second experiment a condition in which visual images were used for counting the corners of letters was compared to a condition in which subjects internally rehearsed the alphabet. The only difference concerned the inferior frontal regions which showed higher activity in rehearsing the alphabet. However, activity in inferior temporal and inferior occipital regions showed a positive correlation to the self-rated vividness of the visual images in the corner counting condition. The results of both experiments yield converging evidence that visual imagery is selectively related to activity of inferior-temporal and occipital regions. They thus support the hypothesis that the cerebral correlate of visual imagery is different from that of non-imaginal thinking.

Adult↗
PubMed1989

Cerebral correlates of imagining colours, faces and a map--I. SPECT of regional cerebral blood flow.

The distribution of regional cerebral blood flow (rCBF) was assessed by single photon emission computerized tomography (SPECT) in subjects during a resting state and during imagining either colours or faces or a route on a map. Twelve out of 30 subjects reported the spontaneous occurrence of mental visual images during the resting state. In these subjects flow in both orbitofrontal regions was higher than in those subjects who had not experienced spontaneous imagery. Voluntary imagery led to an increase of regional flow indices in basal temporal regions of both hemispheres and to a rightwards shift of global hemispheric asymmetry. The local changes were distinctly more marked with faces than with any of the other two stimuli. Imagining faces was also the only condition that led to an increase of activity in the left inferior occipital region which has been suggested by previous studies as being a crucial area for visual imagery. It is concluded that the observed differences of rCBF patterns between imagery conditions are related to the amount of information conveyed by the mental image. In contrast to the results of a companion study on DC-shifts accompanying imagery there was no effect of the visual versus spatial character of the images.

Adult↗
PubMed1989

The effect of lithium on pupillary response to pulses of light in sheep.

Administration of lithium carbonate to sheep in the dose range of 600-1800 mg/day resulted in a linearly described rise in lithium levels in plasma and red blood cells. In contrast to the rodent model but in agreement with the human condition, plasma lithium levels exceeded those of red blood cells. Polydipsia and body weight changes were not evident. At plasma levels of 0.70-0.8 mM/l, lithium attenuated the ability of the pupil to constrict in response to 30-sec pulses of light in the 25-150 microW/cm2 intensity range but not the ability to dilate in the dark. Thus, similar to observations in normal human volunteers and bipolar patients, lithium reduces sensitivity to light. The sheep is proposed as a useful model for studying the actions of lithium.

Animals↗