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Biomedical subjects

M Steiner

Publications and source records attributed to M Steiner.

At least 145 records · Page 8Linked to original sources
PubMed1996

Late luteal phase dysphoric disorder and the thyroid axis revisited.

Late luteal phase dysphoric disorder (LLPDD), also known as premenstrual dysphoria, has been etiologically linked to both depression and thyroid disease. We examined baseline and TRH-stimulated thyroid function in 45 otherwise healthy women with prospectively confirmed LLPDD during the follicular and luteal phases of their menstrual cycles. The means of all thyroid variables were normal. Three (6.8%) subjects had elevated baseline TSH (mild hypothyroidism), and 6 (13.3%) had an exaggerated TSH response (delta max TSH) to TRH (subclinical hypothyroidism). A blunted delta max TSH (< 5 mU/L) was found in only 4.4% of the subjects. History of a past major psychiatric diagnosis (mostly depression) or a current personality disorder correlated with a lower delta max TSH. As baseline TSH, using the new ultrasensitive radioimmunometric assay, correlated strongly with delta max TSH, the utility of the TRH challenge is questioned. Our findings suggest that LLPDD is not related to depression on the basis of this marker and that hypothyroidism is not the cause of LLPDD.

Adolescent↗
PubMed1996

Nuclear architecture and ultrastructural distribution of poly(ADP-ribosyl)transferase, a multifunctional enzyme.

A monospecific autoimmune serum for poly(ADP-ribosyl)transferase (pADPRT) was used to localise the enzyme in ultrastructural cellular compartments. We detected enzyme in mitochondria of HeLa and Sertoli cells. Within the nucleoplasm the enzyme concentration was positively correlated with the degree of chromatin condensation, with interchromatin spaces being virtually free of pADPRT. During spermatogenesis we observed a gradual increase of the chromatin associated pADPRT that parallelled chromatin condensation. The highest concentration was seen in the late stages of sperm differentiation, indicating the existence of a storage form in transcriptionally inactive nuclei. In nucleoli pADPRT is accumulated in foci within the dense fibrillar component. Such foci are seen in close spatial relationship to sites of nucleolar transcription as revealed by high resolution immunodetection of bromouridine uptake sites. It is suggested that nucleolar pADPRT plays a role in preribosome processing via the modification of nucleolus specific proteins that bind to nascent transcripts and hence indirectly regulates polymerase I activity. The persisting binding of pADPRT to ribonucleoproteins may explain the observed disperse enzyme distribution at lower concentrations in the granular component. The fibrillar centres seem to contain no pADPRT. We conclude that known compounds of fibrillar centres like polymerase I are unlikely candidates for modification via direct covalent ADP-ribosylation.

Animals↗
PubMed1996

Effects of cocaine on human platelet aggregation in vitro.

BACKGROUND: A temporal relationship has been established between cocaine ingestion and myocardial infarction, and a cocaine-induced increase in platelet aggregation has been suggested as a possible explanation. However, the mechanisms of cocaine associated coronary thrombosis have yet to be completely elucidated. For this reason, we examined the in vitro effect of cocaine and its metabolites on platelet aggregation. METHODS: Platelet aggregation was tested by obtaining platelet rich plasma from 42 healthy volunteers and incubating the platelet rich plasma in six concentrations of cocaine (ranging from 1.47 to 2940 nmol) for 10 minutes prior to aggregation with ADP 1 microM. The same procedure was used to test the effect of two cocaine metabolites, benzoylecgonine and ecgonine methyl ester, on platelet aggregation. Abnormal results were confirmed by inducing aggregation with ADP at higher concentrations (2.4 and 10 microM) and with arachidonic acid (624 microM). RESULTS: At increasing concentrations, cocaine progressively inhibited ADP and arachidonic acid induced platelet aggregation. No effect was seen with benzoyl ecgonine or ecgonine methyl ester as compared to saline. CONCLUSIONS: These data suggest that under certain conditions cocaine may negatively affect hemostasis by decreasing platelet aggregation.

Adenosine Diphosphate↗
PubMed1996

Preliminary comparison of the polyurethane female condom with the latex male condom in Kenya.

This paper summarizes acceptability data published to date on the innovative female condom, and presents an additional study comparing the acceptability of the female condom and the latex male condom in a sample of low risk women attending private obstetrician/ gynaecologists' clinics in Nairobi, Kenya. Eighty-four percent of all subjects who completed interviewer-assisted questionnaires reported that they liked using the female condom, and more than two-thirds of all the women liked the female condom as much or better than the male condom. Fifty-five percent of the women would use the device in future if it were available. The least liked features were that the device was too large for easy insertion, messy to handle, and reduced sensation. Use became easier and more comfortable with experience. The most liked features were that the device made sex more enjoyable, protected against sexually transmitted diseases and pregnancy, and was under the woman's control. Male partner response was slightly less favourable, and sometimes resulted in women's noncompliance or discontinuation of use, despite the fact that such a device is supposed to empower women. This study provides preliminary data indicating that the female condom is a fairly acceptable method for some Kenyan couples, but recommends further research into safety, cost-effectiveness and hindrances to acceptability.

Adult↗
PubMed1996

Soluble intercellular adhesion molecule-1 in colorectal cancer and its relationship to acute phase proteins.

Increased concentrations of soluble intercellular adhesion molecule-I (ICAM-1) have been reported in a number of diseases including cancer. This study was undertaken to evaluate soluble ICAM-1 in colorectal cancer and its relationship to an unspecific acute phase response. Fifty six patients (25 with advanced colorectal cancer and 31 out-patients after radical surgical treatment) were included. Soluble ICAM-1 was measured by enzyme immunoassay. Four acute phase proteins (C-reactive protein, acid alpha 1-glycoprotein, haptoglobin and ceruloplasmin) were estimated by immuno-nephelometry. No significant increase of soluble ICAM-1 could be demonstrated in the patients compared to a control group (median 273 ng/ml vs. 270 ng/ml). Furthermore, patients with advanced colorectal cancer did not demonstrate elevated soluble ICAM-1 compared to follow-up out-patients. Patients with present acute phase response as determined by C-reactive protein were shown to have increased soluble ICAM-1 compared to patients without acute phase reaction. Using other acute phase proteins no difference for soluble ICAM-1 has been shown. Our data suggest an association between acute phase response and increased ICAM-1 in patients with colorectal cancer which should be considered when the diagnostic and/or prognostic usefulness of soluble ICAM-1 is to be evaluated.

Acute-Phase Proteins↗
PubMed1995

The WAGxDA rat: an animal model of cholinergic supersensitivity.

A heightened response to the muscarinic effects of acetylcholine appears to be involved in many of the symptoms associated with affective disorders. We have developed an animal model for cholinergic supersensitivity to study this involvement in more detail. Our findings on cholinergic supersensitivity and on behavioral despair in this model, the WAGxDA F1 hybrid, are reported here. Female WAGxDA rats show a heightened response to muscarinic agonist in a temperature depression test (TDT) and both males and females show an increased level of inherent despair in a Porsolt swim test; however, this cholinergic supersensitivity does not appear to be based on an increased density or affinity of cholinergic receptors. Other possible mechanisms are discussed.

Animals↗
PubMed1995

Fluoxetine in the treatment of premenstrual dysphoria. Canadian Fluoxetine/Premenstrual Dysphoria Collaborative Study Group.

BACKGROUND: Premenstrual dysphoria shares certain features with depression and anxiety states, which have been linked to serotonergic dysregulation. We evaluated the efficacy and safety of fluoxetine (which selectively inhibits the reuptake of serotonin) in the treatment of premenstrual dysphoria. METHODS: The trial consisted of a single-blind, placebo washout period lasting two menstrual cycles, followed by a randomized, double-blind, placebo-controlled trial of fluoxetine at a dose of either 20 mg or 60 mg per day or placebo for six menstrual cycles. Healthy women meeting criteria for what was then called late-luteal-phase dysphoric disorder were recruited at seven university-affiliated women's health clinics in Canada. The primary outcome measure consisted of visual-analogue scales for tension, irritability, and dysphoria during the late luteal phase of each cycle. RESULTS: Of 405 women enrolled in the placebo washout period, 313 subsequently entered the randomized phase of the study, which lasted six menstrual cycles, and 180 completed it. Fluoxetine at a dose of 20 or 60 mg per day was significantly superior to placebo in reducing symptoms of tension, irritability, and dysphoria, as measured by the visual-analogue scales (P < 0.001). The women who received 60 mg of fluoxetine per day reported significantly more side effects than those who received 20 mg per day or placebo (P < 0.001). CONCLUSIONS: Fluoxetine is useful in the treatment of premenstrual dysphoria. Treatment with fluoxetine at a dose of 20 mg per day reduces the potential for side effects while maximizing therapeutic efficacy.

Adolescent↗
PubMed1995

Ontogenic expression of the erythroid-type glucose transporter (Glut 1) in the telencephalon of the mouse: correlation to the tightening of the blood-brain barrier.

Since Glut 1 was shown to be highly abundant in brain microvessels, its distribution during early developmental stages seems of importance in respect to the timing of blood-brain barrier (bbb) formation in the developing CNS. Here we have followed the temporal expression of the erythroid-type glucose transporter Glut 1 in the telencephalon of the embryonic and newborn mouse, beginning at the 9th intrauterine day. Glut 1 immunofluorescence staining was done on cryosections using a rabbit polyclonal antiserum to purified human erythrocyte glucose transporter. Endothelial cells resp. capillaries were detected by staining with a rhodamin-coupled Bandeiraea simplicifolia lectin (BSL). In parallel, the developmental tightening of the embryonic bbb was assessed by perfusion of mouse embryos with Trypan blue and horse radish-peroxidase. At E9, prior to the onset of intraneural neovascularization, strong Glut 1 immunoreactivity was found in the whole neuroectoderm but only minor staining was seen in the perineural domain. Glut 1 expression remained uniformly distributed in the intraneural tissue at E10, the beginning of intraneural neovascularization in the mouse. From E11 onwards, Glut 1 immunoreactivity was invisible in neuroepithelial cells, but appeared tightly associated with intraneural capillaries. Perfusion of E12 embryos using trypan blue solution and HRP revealed that most parts of the CNS and spinal cord were impermeable to the tracer substances at that stage. Thus, we suggest that the bbb is established very early in CNS development, probably in the course of intraneural neovascularization. In addition, our data indicate that the restriction of Glut 1 expression to the intraneural capillaries reflects the onset of bbb function in the mouse embryo.

Animals↗
PubMed1995

Dual translational start motif evolutionarily conserved in the holin gene of Bacillus subtilis phage phi 29.

Holins represent phage encoded lysis functions required for transit of the phage murein hydrolases to the periplasm. The Lambda S, phage 21 S, and P22 13 holin genes contain a dual translational start motif, beginning with Met1-Lys2-X-Met3. In all cases both start codons at the 5' end of the respective holin gene are utilized. The resulting polypeptides have opposing functions, with the longer product acting as an inhibitor of the shorter one. The 131-codon gene 14 of Bacillus subtilis phage phi 29 encodes the holin function, whereas the downstream gene 15 codes for a lysozyme. phi 29 Gene 14 begins with Met1-Lys2-Met3. Here, we present in vitro and in vivo evidence for the expression of two protein 14 species consisting of 129 and 131 amino acids, respectively. These data suggest that the lysis control mechanism based on two holin species, which has been shown to be operational in the temperature Escherichia coli phages Lambda and 21, and in the Salmonella typhimurium phage P22, is evolutionarily conserved in the lytic B. subtilis phage phi 29.

Amino Acid Sequence↗
PubMed1995

Failure in management of pituitary tumors discussion of 3 cases.

Three patients with pituitary adenomas (ACTH-secreting, non-secretory, and multi-secretory) with unfavorable course, in spite of repeated microsurgery, drug therapy, as well as radiotherapy and radiosurgery, are presented. Each case was re-evaluated for possible flaws in management. Two of the invasive tumors continued to grow, in spite of correct management. The third patient with a pituitary adenoma underwent microsurgical resection, and later following a false positive finding of recurrence, received radiotherapy and underwent radiosurgery. The lesion actually was chronic inflammatory tissue.

Adult↗
PubMed1995

Gamma knife surgery for craniopharyngioma.

We present our results of Gamma Knife surgery for craniopharyngioma in nine patients. The current status of surgery, radiation therapy, intracavitary instillation of radionucleides and Gamma Knife surgery in the management of craniopharyngiomas is discussed.

Adolescent↗
PubMed1995

Vitamin E plus aspirin compared with aspirin alone in patients with transient ischemic attacks.

One hundred patients with transient ischemic attacks, minor strokes, or residual ischemic neurologic deficits were enrolled in a double-blind, randomized study comparing the effects of aspirin plus vitamin E [0.4 g (400 IU)/d; n = 52] with aspirin alone (325 mg; n = 48). The patients received study medication for 2 y or until they reached a termination point. Preliminary results show a significant reduction in the incidence of ischemic events in patients in the vitamin E plus aspirin group compared with patients taking only aspirin. There was no significant difference in the incidence of hemorrhagic stroke although both patients who developed it were taking vitamin E. Platelet adhesion was also measured in a randomized subgroup of both study populations by using collagen III as the adhesive surface. There was a highly significant reduction in platelet adhesiveness in patients who were taking vitamin E plus aspirin compared with those taking aspirin only. Measurement of alpha-tocopherol concentrations confirmed compliance of the patients with the medication schedule, showing a near doubling of serum concentrations of alpha-tocopherol. We concluded that the combination of vitamin E and a platelet antiaggregating agent (eg, aspirin) significantly enhances the efficacy of the preventive treatment regimen in patients with transient ischemic attacks and other ischemic cerebrovascular problems.

Adult↗