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Biomedical subjects

M Steiner

Publications and source records attributed to M Steiner.

At least 235 records · Page 13Linked to original sources
PubMed1991

Viral and cellular oncogene expression during progressive malignant transformation of SV40 transformed human fibroblasts.

In vitro investigation of the multistep neoplastic progression which occurs during transformation of human cells has been hindered by resistance of human cells to both immortalization and tumorigenicity (Mut. Res. 199; 273, 1988). Previously our laboratory established a cell line, HSF4-T12, by transfection of normal human foreskin fibroblasts with the plasmid pSV3-neo which contains the early genes of simian virus 40 (SV40). A multistep progression in karyotypic alterations and transformed phenotype occurred resulting in a neoplastic cell line that was immortal, transformed, and tumorigenic. We have examined changes in the SV40 proteins, large T (T-antigen) and small t (t-antigen) antigens, and in the cellular protein, p53, during progressive transformation of these cells. Total viral protein expression relative to total cellular protein increased following immortalization of HSF4-T12 as did the ratio of T-antigen to t-antigen. Interestingly, no significant change in DNA content accompanied immortalization. However, during the progressive in vitro transformation of HSF4-T12 which occurred primarily post-immortalization, DNA index increased to 1.6 but only small additional increases in T-antigen expression were seen. No consistent or critical role for t-antigen in development of the tumorigenic phenotype was found in this system.

Antigens, Viral, Tumor↗
PubMed1991

Effects of a multiple mild infra-red-A induced hyperthermia on central and peripheral pulse waves in hypertensive patients.

The paper reports on the effects of multiple whole-body infra-red-A irradiational (IRA) on 13 male patients known to have stage I or stage II essential arterial hypertension (WHO definition). The peripheral blood pressure was decreased significantly by IRA exposures. The lowered diastolic blood pressure lasted into posttreatment time. This effect is regarded as a consequence of an improvement in peripheral haemodynamics. A measure of this improvement is the different shape of the blood pressure pulse waves. Calculation and comparison of the spectral components of the recorded pulse signals show that these components are useful for a prediction of the blood pressure lowering effect.

Adult↗
PubMed1991

Contributions of occipital and temporal brain regions to visual and acoustic imagery--a spect study.

Regional cerebral blood flow (rCBF) was assessed by means of HMPAO-SPECT in two experimental groups. In a control condition both groups listened to abstract words, in the experimental condition they heard five names of objects. One group was advised to form visual images of the objects, the other group was advised to form acoustic images of the sounds made by these objects. Post-experimental questionnaires revealed that most of the subjects in the acoustic imagery condition had had visual images in addition to the acoustic ones. Both imagery conditions lead to approximately equal increases of rCBF in the left inferior occipital region and in the left thalamus. Flow increases in both hippocampal regions and the right inferior and superior temporal regions were larger in the acoustic than in the visual imagery condition. It is concluded that only the activation of left inferior occipital and left thalamic regions can be interpreted as being related to modality-specific visual aspects of imagery.

Auditory Perception↗
PubMed1991

Retinal pigment epithelium response and the use of the EOG and Arden Ratio in depression.

Supersensitivity to light in depression has been observed with both neuroendocrine and ophthalmological assessment methods. The biological defect underlying this abnormality may be localized in either the photoreceptors, the retinal pigmented epithelium, or some interaction of the two. The present study assessed responses of the retinal pigmented epithelium (RPE). All subjects underwent thorough ophthalmological and mood assessments. The electrooculogram (EOG) was used to measure standing potentials of the RPE in response to light and dark in 20 normal controls and 20 unmedicated depressed patients. Both groups were matched for age, sex, time of day for the procedure, and prior lighting history. Reproducibility of the EOG measure on two independent occasions for 13 control subjects had an intrasubject reliability coefficient of 0.70. The mean +/- SD Arden Ratio (light peak/dark trough) of the control group (2.13 +/- 0.42) compared to the depressed group (2.28 +/- 0.72) showed no statistical difference. There was, however, a significant difference between groups in response to darkness; depressed patients had a lower standing potential in the dark compared to controls, suggesting supersensitivity to light. No difference between groups was detected in standing potentials at baseline or in response to light. Supersensitivity to light in depression may be related to abnormal function of the RPE, but the inherent reliability of the EOG precludes the use of this instrument in pursuing this hypothesis.

Adult↗
PubMed1991

Development of small-diameter vascular prostheses which release bioactive agents.

A porous, distensible, tubular membrane which incorporates albumin and basic Fibroblast Growth Factor (bFGF), and is potentially utilizable as a bioactive small-diameter vascular prosthesis, was fabricated by a combined spraying, phase-inversion technique using a suspension of albumin and bFGF into a polyetherurethane-urea (Biomer) solution in dimethylacetamide (DMA). Scanning electron microscopy showed a material with an open-cell trabecular structure and small particles of albumin and/or bFGF entrapped in the bulk of the polyurethane trabeculae. The material released albumin and bFGF at an approximately constant rate for at least 2 weeks. The bFGF initially incorporated in the polymer remained biologically active as shown by in-vitro proliferation of human endothelial cells.

Albumins↗
PubMed1991

Influence of vitamin E on platelet function in humans.

alpha-tocopherol, a natural antioxidant, has been found to inhibit platelet aggregation and release when tested in an in vitro system. This effect of vitamin E was thought to be due to a slight reduction of platelet cyclooxygenase activity and inhibition of lipid peroxide formation. Aggregation of platelets derived from individuals on a dietary supplementation of alpha-tocopherol ranging from 400 to 1200 IU/day showed no significant reduction. The discrepancy between the effectiveness of alpha-tocopherol in vitro and ex vivo is probably related to the levels of alpha-tocopherol attainable in platelets and plasma. Investigation of the effect of alpha-tocopherol on platelet adhesion showed a major inhibitory activity at doses of vitamin E as low as 200 IU/day. Measurements were performed in a laminar flow chamber at both high and low shear rates. Reduced platelet adherence to collagen, fibrinogen, and fibronectin could be documented. alpha-tocopherol-enriched platelets that adhered to adhesive surfaces failed to show the usual long thin pseudopodia but exhibited short, rounded, blunt projections. The reason for this shape change is still unclear, but we speculate that it may be causing the vitamin E-induced reduction of platelet adhesiveness. We believe that dietary supplementation with this vitamin could play a role in the treatment of thromboembolic disease, especially when given in conjunction with an inhibitor of platelet aggregation.

Blood Platelets↗
PubMed1991

Caries prediction on the basis of past caries including precavity lesions.

The purpose of the present work was the construction of statistical models which allow the prediction of future high caries increments on the basis of the state of primary teeth and first molars taking into account both precavity lesions and DF experience. A child was considered to be experiencing 'high caries increment' when it had at least four new lesions (new DFS) 4 years after the first examination. Two data sets of children aged 7-10 years were analysed: (1) 803 children examined in 1980 and in 1984. The proportion of children with 'high caries increment' was 25.0%. (2) 477 children examined in 1984 and in 1988. In this group, the proportion of children with high caries increment was 16.6%. In the first group with higher prevalence of caries, sensitivity and specificity were found to be on average at 70%. In the second group, sensitivity and specificity were 77% on average. This results shows that caries prediction may be at least as successful when a 'refined' set of clinical data is used instead of a less extensive set of caries data complemented by salivary buffering capacity and microbiological data.

Child↗
PubMed1991

The dexamethasone suppression test in borderlines: is it useful?

The relationship between borderline personality disorders (BPD) and major depressive disorder (MDD) continues to be controversial. A reliable biological marker for depressed BPD patients would not only support the diagnosis but could also help in predicting treatment outcome. A large sample of psychiatric patients was screened and data on the Dexamethasone Suppression Test (DST) were obtained for 67 patients who met the criteria for BPD by scoring 7 or greater on the Diagnostic Interview for Borderlines. The DST was positive in 23.9% of the cases. Fifty cases of BPD also met the Research Diagnostic Criteria for MDD. The DST was positive in 26.0%. Of the 50 patients with MDD, 34 also met the criteria for endogenous depression. Only 17.6% of this subgroup had positive results on the DST. The low sensitivity and specificity of the DST for depression in BPD patients suggests that the DST is not a useful test in differentiating BPD patients with MDD from those without MDD. The possible reasons for the DST not being useful in this population are discussed. These findings raises further questions about the nature of the depression suffered by BPD patients.

Adolescent↗
PubMed1991

A multidisciplinary treatment approach to postpartum psychoses.

Psychosis after childbirth occurs as a result of unique developmental and social demands. The authors have developed a treatment approach for the management of postpartum psychotic mothers admitted with their babies, based on their experience on an acute psychiatric inpatient unit with a special interest in the treatment of postpartum disorders. Five phases of the acute illness and recovery process are outlined. For each phase, a typical clinical situation, the specific tasks of the phase, and special problem areas are presented. The management guidelines are based on a multidisciplinary team and phase-oriented approach.

Combined Modality Therapy↗
PubMed1991

[Caries prevalence and gingival inflammation in recruits in 1985: the influence of prevention].

A total of 753 conscripts (age 20) examined in 1985 showed on average 8.6 DMF teeth upon clinical examination. When subjected to a standardized examination supplemented by bite-wing radiographs of the buccal segment, 0.5 MT, 4.2 DT and 5.4 FT equivalent to a DMFT of 10.1 were found. Three per cent of the subjects were caries-free (DFT = 0). Caries experience in anterior teeth DFS greater than 0) was diagnosed in 21% of the recruits but 85% of them had suffered dentinal caries or showed fillings on the bite-wing radiographs (DFS greater than 0). Among the total of 18.8 DF sites, 5 were D sites, and 83% of the D sites were dentinal radiolucencies in molars and premolars. An annual increase of 1.55 DFS was estimated for the age interval 15-20 years. Recruits from communities with preventive programs at school had 17.0 DFS (9.1 DMFT) while those from communities lacking organized prevention at school had 21.2 (11.3 DMFT). The recruits from the Canton of Vaud, who had benefited from a program of salt fluoridation, comprising salt for domestic use and for bakeries and restaurants, from 1970 to 1985, showed only 11.6 DFS (7.1 DMFT). There was less gingival bleeding and calculus in recruits from the Canton of Zurich where supervised toothbrushing has been carried out 4 to 6 times a year since 1963/64 at least through school-grades 1-6 than in the remaining recruits.

Adult↗
PubMed1991

Abnormally high level of C4b binding protein and deficiency of free fraction of protein S in a patient with systemic lupus erythematosus and recurrent thromboses.

A patient with systemic lupus erythematosus and numerous thrombotic accidents was found to have a deficiency of the free fraction of protein S, most likely due to an abnormally high level of C4b binding protein. These abnormalities, unique in comparison to 4 other patients with hypercoagulation states, were partially corrected with cyclophosphamide. There was no evidence of a consumption of complement components. The interactions between the hemostasis system and the complement cascade are discussed.

Adult↗
PubMed1991

[The prevalence of deciduous dental caries in 16 communities of the Canton of Zurich in 1964 to 1988].

Caries prevalence in 16 communities of the Canton of Zurich decreased in the primary dentition by more than 70% from 1964 to 1988. This corresponds to the decrease in the permanent dentition during the same period. There was no increase of the caries prevalence in primary incisors (nursing bottle caries) detectable in the eighties. The caries prevalence in the city of Zurich was similar to that in the 16 rural communities. In other European countries, caries prevalence was higher in the eighties.

Age Factors↗
PubMed1991

[The prognostic value of evoked potentials in early neurologic rehabilitation of patients with the apallic syndrome].

In 22 patients with apallic syndrome brainstem auditory and somatosensory evoked potentials were recorded, in 8 patients the course during rehabilitation was observed. Clinically the patients were scored with Glasgow-coma scale, Karnofsky-index and Goldenberg-scale. The outcome of rehabilitation was estimated by the "Glasgow-outcome scale". No correlation was found between results of evoked potentials and clinical state. First evoked potentials measurements of apallic patients allowed no prognosis. Evoked potentials are an important prognostic factor after severe head trauma, but have no value for the prognosis of apallic patients.

Adolescent↗
PubMed1990

Unequal distribution of membrane components between pseudopodia and cell bodies of platelets.

Platelet pseudopodia were compared to platelet cell bodies with respect to their lipid composition, fatty acid distribution and protein composition. The methodology for producing pseudopodial preparations of platelets stimulated with thrombin, ADP or calcium ionophore was established. The separation of pseudopodia and cell bodies was verified by electron microscopic examination of the respective platelet components. Lipid analyses demonstrated a preponderance of lysophospholipids and sphingomyelin in pseudopodial preparations and a large increase in mono-, di- and tri-ene fatty acids as compared to cell bodies. Changes were also evident in the protein composition evaluated by one- and two-dimensional SDS-polyacrylamide gel electrophoresis and by [32P]ATP labeling of exofacial membrane proteins. A protein of approximately 68 kDa which reacted strongly with antibody to PlA1, was prominantly displayed in platelet pseudopodia. Thus, our studies demonstrate a heterogeneous distribution of lipids and proteins in a mammalian membrane system which may have important implications for the functional behavior of the cell.

Adenosine Diphosphate↗
PubMed1990

Fish oil: a potent inhibitor of platelet adhesiveness.

The effect of fish oil administration on platelet function was studied in eight normal individuals, four men and four women, who received fish oil equivalent to 6 g eicosapentaenoic acid per day for a period of 25 days. Platelet aggregation, platelet adhesion, phospholipid and fatty acid distribution were measured at periodic intervals before, during, and after the period of fish oil administration. Platelet aggregation induced by arachidonic acid, adenosine diphosphate, and collagen showed a moderate increase in ED 50 in response to the administration of fish oil. Conversely, platelet adhesion to fibrinogen and collagen I, which was studied at low shear rates in a laminar flow chamber, showed a striking 60% to 65% decrease after fish oil supplementation of the diet. The change in adhesiveness could be correlated with the pseudopodia formed in response to agonistic stimulation. Scanning electron microscopic examination of adherent platelets showed an overall reduction of pseudopodia that appeared short and stubby on fish oil administration. The profile of the fatty acids extracted from plasma confirmed compliance of the volunteers with their dietary supplements. Analysis of phospholipids showed changes in sphingomyelin, lysophosphatidylcholine, and phosphatidylcholine between pseudopodia and platelet cell bodies. Fish oil administration did not affect their overall distribution except for a moderate decrease in phosphatidylethanolamine in platelet pseudopodia. Changes were also recognized in the total fatty acids extracted from platelets, affecting primarily arachidonic acid, eicosapentaenoic acid, and docosahexaenoic acid. There were no changes in platelet adhesiveness in a group of five normal individuals who received a vegetable oil supplement of equal dose and duration as that of the fish oil. We conclude from these studies that fish oil, at least when administered over a limited period of time, is an effective inhibitor of platelet adhesiveness.

Adenosine Diphosphate↗