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Biomedical subjects

M Steiner

Publications and source records attributed to M Steiner.

At least 343 records · Page 19Linked to original sources
PubMed1986

Identification of the immunoglobulin G receptor of human platelets.

The binding site of IgG on human platelets was studied by the use of the cleavable heterobifunctional cross-linking agent N-succinimidyl (4-azidophenyldithio)propionate. Binding characteristics of the derivatized IgG were similar to normal IgG. Periodate-borohydride treatment of platelets also did not significantly alter their ability to bind IgG. N-Succinimidyl (4-azidophenyldithio)propionate was bound to IgG via a succinimidyl ester and then photolyzed in the presence of intact platelets. Their membrane glycoproteins were first tritiated by the periodate-borohydride method. The cross-linked product was analyzed by two dimensional sodium dodecyl sulfate-polyacrylamide gradient gel electrophoresis. The non-reduced first-dimension gels were subjected to 5% 2-mercaptoethanol prior to separation in the second dimension. Such gels were then evaluated by fluorography, silver staining, and counting the radioactivity of sequential gel strips in the area of cross-linking. The protein complexes at the interface between stacking and running gel were further resolved in isoelectric focusing gels. One IgG-containing band could be identified. After reduction, the constituent proteins of the cross-linked complex were analyzed by sodium dodecyl sulfate-polyacrylamide gradient gel electrophoresis and subsequent immunoblotting with an antiserum against platelet membrane glycoproteins. All of these studies gave evidence of glycoprotein IIIa as the receptor of IgG. Based on the results of the different experimental approaches, we conclude that glycoprotein IIIa is the IgG receptor in human platelets.

Azides↗
PubMed1986

Role of glycosaminoglycans in calcium metabolism of human platelets.

Changes in intracellular Ca2+, [Ca2+]i, were measured in control and chondroitin ABC lyase-pretreated platelets. [Ca2+]i was measured with the fluorescent calcium probe Quin2. Chondroitin ABC lyase removed chondroitin 4-sulfate from the platelet surface without inducing shape change or release of serotonin. Compared to similarly prepared controls, enzyme treated platelets showed an increase of [Ca2+]i in response to stimulation by various agonists at high (1 mM) extracellular Ca2+ concentration. At low Ca2+ in the medium (1 mM EGTA), such platelets responded to agonists with a decreased rise in [Ca2+]i compared to the controls. These studies indicate that selective removal of glycosaminoglycans may sensitize platelets to the action of platelet aggregating agents. In addition, glycosaminoglycans may have a calcium storage function.

Blood Platelets↗
PubMed1986

The treatment of nonseminomatous testicular tumors: 15 years experience.

Thirty-two patients with nonseminomatous germ cell tumors of the testis were treated at the Northern Israel Oncology Center during the years 1968-1983. The patients were divided into two groups. Group I included 18 patients treated from 1968 to 1976; in group II there were 14 patients treated with combination therapy containing cis-platinum in the years 1977 to 1983. The actuarial survival rate at 38 months from diagnosis is 47% in group I patients and 86% in group II patients. The development of modern radiological techniques, biochemical markers for accurate staging, and the use of cis-platinum-containing combination chemotherapy made this disease curable. New treatment modalities are needed for patients with bulky disease at presentation.

Adolescent↗
PubMed1986

Ultrastructure of monkey (Macaca radiata) spermatozoa: effect of gossypol in vivo.

The present study examines the ultrastructure of ejaculated spermatoza from bonnet monkey, Macaca radiata under normal conditions, with gossypol treatment and during recovery from such treatment. Monkeys were fed orally with gossypol acetic acid (GAA) for 3 months (4 mg/monkey/5 days a week). Semen samples collected by electro-ejaculation, and the spermatozoa were examined using both light and electron microscopy. The degree of motility was also noted by Kalla et al. Ejaculated spermatoza were immotile 90 days after GAA treatment, but little evidence for any abnormality in the spermatozoa could be seen by light microscopy. Some ultrastructural changes were observed, but not to the extent previously reported in spermatozoa of Macaca fascicularis. After termination of treatment, semen samples were obtained every 5th day until sperm count and motility recovered to the normal level. After 90 days only a small proportion of spermatozoa showed abnormal structure. We conclude that in a subhuman animal model gossypol induced effects on sperm motility and morphology are reversible.

Administration, Oral↗
PubMed1986

Testicular seminoma: results of treatment at the Northern Israel Oncology Center.

The survival, and the patterns and mechanisms of failure of 41 patients with pure testicular seminoma treated at the Northern Israel Oncology Center from 1968 to 1983 were analyzed. The actuarial 5-year survival of all patients was 85.4% and of stage I patients, 92.2%. Treatment failures were analyzed. The following conclusions were reached: in order to increase the cure rate, the use of combination chemotherapy as the initial treatment modality in advanced seminoma is recommended. In cases of transscrotal approach, the scrotum should be irradiated. Adjuvant mediastinal irradiation is not needed.

Combined Modality Therapy↗
PubMed1986

Primary drug-resistant tuberculosis in children. Emergence of primary drug-resistant strains of M. tuberculosis to rifampin.

A prospective study of primary drug-resistant strains of Mycobacterium tuberculosis among children was begun at the Kings County Hospital Medical Center of Brooklyn in 1961 and reported at 5 4-yr periods through 1980. The present report extends our observations of primary drug-resistant tuberculosis in children through 1984. The salient finding in the present report was the increase in primary drug resistance to rifampin, 3 of 19 strains resistant in the last period of study (1981 to 1984) as compared with 1 of 96 strains isolated in the previous 3 periods of study (1969 to 1980). This increase was significant (p less than 0.02) even though the number of strains isolated was small. There were continued low resistance rates to ethambutol and para-aminosalicylic acid and stable resistance rates for isoniazid and streptomycin.

Adolescent↗
PubMed1986

Diagnosing premenstrual tension syndrome.

The presence of a premenstrual tension syndrome (PMTS) should be considered during the clinical assessment of any women of childbearing age with intermittent or fluctuating psychological symptoms. Appropriate identification of this disorder depends on knowledge of its specific diagnostic features, most particularly its time-limited course. The clinician must also be aware that the syndrome can coexist with, exacerbate, or be exacerbated by other psychological distress or illness. Through the presentation of four case histories, the authors discuss the diagnostic complexities of PMTS and the treatment implications of a diagnosis of PMTS.

Adult↗
PubMed1986

Psychosis resulting in suicide in a patient with primary hyperparathyroidism.

A case is reported of a patient presenting to the psychiatric unit of our hospital with symptoms of depression and found to have an organic psychosis. On routine SMA-12 investigation (12 channel auto analyzer), elevated serum calcium was detected on admission leading to the diagnosis of primary hyperparathyroidism (PHPT). The surgical removal of a parathyroid adenoma was followed by a rapid return of biochemical abnormalities to normal ranges. In spite of appropriate psychiatric management and fluctuations in the patient's clinical condition, the organic psychosis was unaltered and culminated in suicide 4 months after admission.

Calcium↗
PubMed1986

Nodal gliomatosis and alpha-fetoprotein production. Two unusual facets of grade I ovarian teratoma.

We describe the case of a 10-month-old infant who had a grade I solid teratoma of the ovary. It is remarkable that the tumor was accompanied by nodal gliomatosis and elevated serum alpha-fetoprotein (AFP) level. To our knowledge, this is the first description of nodal gliomatosis in the absence of gliomatosis peritonei, and the fifth report of elevated serum AFP with a pure teratoma. Like gliomatosis peritonei, nodal gliomatosis appears to be a benign condition, requiring no adjuvant therapy. The nature of the nodal implants was confirmed by positive immunoreactivity for glial fibrillary acidic protein. By a similar method, AFP was found in the primary tumor in cells lining yolk-sac-like vesicles and intestinal-type glands.

Choristoma↗
PubMed1985

Biological activity of platelet activating factor-amidophosphonate (PAF-AP), a novel phosphonolipid selective inhibitor of platelet activating factor (PAF).

A novel amidophosphonate analog of Platelet Activating Factor (PAF), trimethyl (3-phosphonopropyl) ammonium hydroxide (R)-mono[2-acetamido-3-(hexadecyloxy)propyl] ester (PAF-AP), was synthesized. A potent inhibitor of aggregation induced by Platelet Activating Factor, arachidonic acid, Ca2+-ionophore, ADP, and thrombin, PAF-AP had no or very little effect on aggregation induced by epinephrine and collagen. Inhibition of phospholipase A2 and C2 activity was suggested from suppression of release of [14C]-arachidonic acid from pre-labeled platelet glycerophospholipids.

Adenosine Diphosphate↗
PubMed1985

Asymmetrical loss of sialic acid from membrane glycoproteins during platelet aging.

Platelet cohorts prepared from less than or equal to 24 hour old rabbit platelets were infused into myelosuppressed recipient animals and allowed to age in them. Serial withdrawals of platelets at 24 hour intervals revealed a sharp drop in total platelet N-acetylneuraminic acid. Platelet membrane proteins were double labeled by reductive methylation of free amino groups in the presence of [14C]-formaldehyde and by metaperiodate oxidation of sialic acid residues followed by reduction with [3H]-NaBH4. Senescence of platelets in vivo is associated with a disproportionate loss of metaperiodate-oxidizable residues from a glycopeptide of M.W. 45,000.

Animals↗
PubMed1985

Liquid chromatographic determination of inhibition of monoamine oxidase activity in platelet rich plasma of depressed patients treated with phenelzine.

Monitoring platelet monoamine oxidase activity in plasma of depressed patients receiving monoamine oxidase inhibitors is used as an indicator of therapeutic dosage and efficacy. In this study enzyme activity in platelets vs platelet rich plasma was compared. An aliquot of platelet rich plasma (PRP) was incubated with 4-hydroxy-3-methoxy-benzylamine as substrate. After stopping the enzymatic reaction, m-hydroxybenzaldehyde was added to the mixture as internal standard. The reaction mixture was extracted with toluene to isolate vanillin, the deamination product of the substrate, and the internal standard. The toluene layer was collected and back extracted into dilute tetramethylammonium hydroxide. An aliquot of the aqueous layer was chromatographed on a non-silica resin base reversed phase column with an alkaline phase. The peaks were detected by an absorbance detector at 350 nm. There was no significant difference in the decrease of monoamine oxidase activity when determined using platelet rich plasma versus washed platelets.

Benzaldehydes↗