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Biomedical subjects

H Klein

Publications and source records attributed to H Klein.

At least 235 records · Page 13Linked to original sources
PubMed1988

Health concerns of high school students and teachers' beliefs about student health concerns.

Information about health concerns of adolescents can assist in assessment and treatment of their particular medical problems. Because teachers are important figures in the lives of young people, their beliefs about student health concerns are often solicited. A survey to assess adolescent health concerns and teachers' beliefs about student health concerns was conducted in two urban high schools on a sample of 831 students and 146 teachers. An assessment of 22 health concerns among the students revealed that a moderate level of concern existed on virtually every issue (the mean percentage "very concerned" was 55%), with black students and girls reporting more concern about many topics. In contrast, teachers significantly underestimated the level of concern of the students by an average of 13%, consistently having inaccurate beliefs about the types and level of student concerns. Students are concerned about health issues and are in need of health education and counseling in these areas. Teachers are not always aware of the level and types of student health concerns and may not be good sources of information about adolescent health.

Adolescent↗
PubMed1988

Morphometric assessment of bone marrow fiber content in acute nonlymphatic leukemia at presentation.

The number of intersections of reticulin fibers per sq mm of fat cell-free marrow parenchyma with the lines of a grid ocular (i/sq mm) represents an objective measure of the bone marrow reticulin fiber content. This method was used to assess the reticulin fiber content of bone marrow biopsies from 50 cases of acute nonlymphatic leukemia (ANLL) at presentation and 20 controls. Seventeen (34%) of the 50 patients with ANLL showed fibrosis, i.e., had a reticulin fiber score above the upper 99% confidence limit of the mean of 20 normal control biopsies. The frequencies of marrow fibrosis, as defined above, were 47% (16 of 34) in the combined subtypes of undifferentiated (M0), myeloid (M1), myelomonocytic (M4) and monocytic (M5) acute leukemia and 7% (1 of 15) in the combined subtypes of acute myeloid leukemia with partial maturation (M2) and acute promyelocytic leukemia (M3) (P less than .01). The fibrosis scores of M0/M1/M4/M5 patients were significantly higher than those of M2/M3 patients (P less than .05) and of controls (P less than .005). Finally, the survival of patients with and without fibrosis was not different.

Acute Disease↗
PubMed1987

Tissue distribution and biochemical and functional properties of Tp55 (CD27), a novel T cell differentiation antigen.

Two monoclonal antibodies (CLB-CD 27/1 and CLB-CD 27/2) were raised against a novel determinant on human T lymphocytes. One of these antibodies, CLB-CD 27/1 (clone 9F4), was grouped by the Third International Workshop and Conference on Human Leucocyte Differentiation Antigens together with three other monoclonal antibodies (VIT 14, OKT 18A, and S152) in the new cluster CD27. In this paper we show that antibodies belonging to this cluster recognize an antigen present on a large subset of peripheral T lymphocytes and most medullary thymocytes. At least two different nonoverlapping epitopes were identified with directly labeled monoclonal antibodies. Immunoprecipitation studies indicate that the target antigen of CD27 antibodies is a polypeptide of 55 kDa, which appears in the form of a disulfide-linked homodimer on the T lymphocyte membrane (Tp55). Stimulation of T cells via the T3/T cell antigen-receptor complex, with either phytohemagglutinin or CD3 monoclonal antibodies, resulted in a fivefold increase in the membrane expression of Tp55, whereas activation by phorbol myristate acetate caused a marked down-regulation. Moreover, an additional molecule of 32 kDa was precipitated from the membrane of activated but not of resting T cells. Addition of CD27 antibodies to cultures stimulated with either phytohemagglutinin or CD3 monoclonal antibody led to enhanced proliferation, whereas no effect was observed in phorbol myristate acetate or interleukin 2-stimulated cultures. The possible role of the Tp55 antigen in T cell activation is discussed.

Antibodies, Monoclonal↗
PubMed1987

Catalysis in the crystal: synchrotron radiation studies with glycogen phosphorylase b.

Direct observation of the progress of a catalysed reaction in crystals of glycogen phosphorylase b has been made possible through fast crystallographic data collection achieved at the Synchrotron Radiation source at Daresbury, UK. In the best experiments, data to 2.7 A resolution (some 108,300 measurements; 21,200 unique reflections) were measured in 25 min. In a series of time-resolved studies in which the control properties of the enzyme were exploited in order to slow down the reaction, the conversion of heptenitol to heptulose-2-phosphate, the phosphorylysis of maltoheptaose to yield glucose-1-phosphate and the oligosaccharide synthesis reaction involving maltotriose and glucose-1-phosphate have been monitored in the crystal. Changes in electron density in the difference Fourier maps are observed as the reaction proceeds not only at the catalytic site but also the allosteric and glycogen storage sites. Phosphorylase b is present in the crystals in the T state and under these conditions exhibits low affinity for both phosphate and oligosaccharide substrates. There are pronounced conformational changes associated with the formation and binding of the high-affinity dead-end product, heptulose-2-phosphate, which show that movement of an arginine residue, Arg 569, is critical for formation of the substrate-phosphate recognition site. The results are discussed with reference to proposals for the enzymic mechanism of phosphorylase. The feasibility for time-resolved studies on other systems and recent advances in this area utilizing Laue diffraction are also discussed.

Animals↗
PubMed1987

Metabolism of androgens in human benign prostatic hyperplasia: aromatase and its inhibition.

As an extension of our studies on androgen metabolism in epithelium and stroma of human benign prostatic hyperplasia (BPH) tissue our attempts to demonstrate the presence of aromatase are described. Additionally, the question is raised whether the aromatase inhibitor 17 alpha-oxa-D-homoandrosta-1.4-diene-3.17-dione (testolactone) might also act by inhibition of 17 beta-hydroxysteroid dehydrogenase (17 beta-HSDH). In vitro metabolism and inhibition were analyzed by TLC. The main results were: (1) Two aromatase assays (estrone formation and tritium release) were tested with placenta microsomes. Identical results were obtained (Km = 43 +/- 7 nmol/l n = 5; Vmax = 100 resulted in recovery of the aromatase activity added. (3) In BPH tissue alone, formation of estrone from androstenedione could not be detected (less than 7 x 10(-17) mol/min per mg protein, n = 8). (4) 4-Hydroxyandrostenedione inhibited placental aromatase (Ki = 37 nmol/l) distinctly better than 17 beta-HSDH from human BPH (Ki = 18 mumol/l), whereas the Ki values for testolactone (3.7 and 29 mumol/l, respectively) were more similar. It is concluded that aromatization of androgens is not an important pathway in BPH tissue. An alternative mode of action of testolactone by inhibition of 17 beta-HSDH is discussed.

17-Hydroxysteroid Dehydrogenases↗
PubMed1987

[Arrhythmia profile and sudden cardiac death in early and late resuscitated patients following myocardial infarct].

The arrhythmia profile has been studied in 40 patients (pts) with acute myocardial infarction (MI) resuscitated early (less than 24 hours post MI, group I) and late (4-12 weeks post MI, group II) using 24 h Holter monitoring (HM) at the time of LV- and coronary angiography (HM A) with an average follow-up of 27 months (7-61) (HM B). Forty pts with an acute MI without resuscitation served as controls (group III). Mortality for sudden cardiac death (scd) (death within 24 hours after beginning of symptoms) was significantly higher in group II (6/14 or 42.9%; 13% per year) than in group I (4/26 or 15.4%; 5.9% per year) (p less than 0.05) or in group III (3/40 or 7.5%; 1.8% per year) (p less than 0.001). In HM A there were no significant differences with regard to PVCs and complex arrhythmias using qualitative and quantitative analysis in groups I-III as well as between survivors and scd-pts. In HM B survivors in group II had significantly more PVCs (mean = 1347), couplets (mean = 29) and salvos (mean = 11) than in group I (PVC, mean = 355; couplets, mean = 3; salvos, mean = 0.1; p less than 0.05) or in group III (PVC, mean = 455; couplets, mean = 4; salvos, mean = 0.8; p less than 0.05). They also showed significantly more PVCs (mean = 1480), couplets (mean = 35) and salvos (mean = 15) than in HM A (PVC, mean = 1347; couplets, mean = 3; salvos, mean = 0; p less than 0.05). There were no significant differences between HM A and HM B in groups I and III. It can be concluded that the risk of sudden cardiac death was increased in pts resuscitated 4-12 weeks post MI in comparison to pts with early resuscitation or without resuscitation post MI. In these high risk pts repeated studies using Holter monitoring were helpful in estimating the further risk of sudden cardiac death.

Adult↗
PubMed1987

[Significance of coupling intervals of spontaneous ventricular arrhythmias in long-term ECG in patients with coronary heart disease].

Coupling intervals of premature ventricular beats and complex arrhythmias were studied by 24-h ambulatory electrocardiographic recordings in 76 patients (35 sudden death patients and 41 survivors) with coronary artery disease. A first Holter (HM 1) was recorded at the time of left ventricular angiography and a second Holter (HM 2) after a mean interval of 34.4 +/- 11.2 months (range 2-61 months). All patients were only treated medically. The mean heart rate was significantly faster in patients who died suddenly than in survivors in both HM 1 and HM 2 (p less than 0.01). In HM 1, there were no significant differences in mean coupling intervals between patients who died suddenly and survivors, whereas in HM 2, coupling intervals of premature ventricular beats and couplets were significantly shorter in patients who died suddenly than in survivors (p less than 0.05). Patients with coupling intervals for couplets less than 500 ms died significantly earlier than those patients with coupling intervals greater than 500 ms (p less than 0.05). Our data show that there is a relationship between heart rate, coupling intervals and sudden death. Patients with fast heart rates and coupling intervals for couplets less than 500 ms represent a group at high risk of sudden death.

Adult↗
PubMed1987

[Ectopic atrial tachycardia: surgical therapy (case report and review of the literature)].

Focal atrial tachycardia with frequencies up to 200/min in an 11-year-old girl had been resistant to drugs over a period of 5 years. An electrophysiological study demonstrated a left atrial ectopic tachycardia. Intraoperative epicardial mapping localized the automatic focus at the base of the left atrial appendage. Excision of the appendage and cryoablation of the adjacent area were performed using cardiopulmonary bypass. Histological examination of the excised tissue showed no specific alterations aside from islets of fatty tissue. The girl has been in sinus rhythm and has shown no tachycardias during the 6 months following the operation. Review of the literature covering 17 cases of right and 12 cases of left atrial focal tachycardia indicates excision of the atrial tissue in combination with cryoablation to be the treatment of choice to ensure success.

Child↗
PubMed1987

[Antiarrhythmia effectiveness of oral sotalol in patients with coronary heart disease and ventricular tachycardias].

In order to assess whether Sotalol is an effective drug in patients (pts) with life-threatening ventricular tachyarrhythmias, programmed ventricular stimulation (PVS) was performed in 30 pts with recurrent ventricular tachycardia (VT) or ventricular fibrillation (VF) after myocardial infarction. Prior to Sotalol, pts were treated with a mean of 3.1 +/- 1.2 antiarrhythmic class I drugs. None of these drugs prevented VT or VF. During the control study, sustained VT was induced in 15 pts (50.0%), non-sustained VT in 8 pts (26.7%) and VF in 7 pts (23.3%). Treatment with Sotalol 240-320 mg/day was started and after 3.1 +/- 1.1 weeks PVS was repeated. In none of the pts could VF be induced; sustained VT and non-sustained VT were still inducible in 4 pts (13.3%) and in 6 pts (20.0%) respectively. In 20 pts (66.7%) either no or only a short ventricular response was inducible. Our data show that Sotalol appears to be an effective antiarrhythmic agent in pts with life-threatening ventricular tachyarrhythmias.

Administration, Oral↗
PubMed1986

Direct radioimmunoassay for human atrial natriuretic peptide (hANP) and its clinical evaluation.

A direct radioimmunoassay for the rapid and accurate detection of human ANP from unextracted plasma is described. The sensitivity was approximately 50 pg/ml, respectively 2.5 pg/tube, the intra-assay variation 4%, and the inter-assay variation less than 12%. Rat ANP (1-28, 5-25, 5-27 and 5-28), oxydized and reduced hANP as well as plasma samples from various patients run in parallel to the 1-28 hANP standard curve. These findings imply, that the antibody primarily recognizes the mid-region (amino acids 6-25) of the intact ANP, that the C-terminal portion further increases the immunoreactivity, and that circulating plasma hANP is reliably measured. Plasma hANP ranged from 50-166 pg/ml (mean +/- SD: 98.3 +/- 44.6) in healthy individuals, there was no significant difference between samples were drawn in upright or lying position, the apparent half-life of injected hANP was 5.65 minutes. Patients with liver cirrhosis revealed significantly higher hANP levels of 244.5 +/- 173.5 pg/ml. Patients with various forms of cardiac disease had hANP concentrations ranging from 50 to 1744 pg/ml, depending at least partially on the right atrial pressure. No difference was observed if the samples were drawn from either right or left intracardial locations. Our findings with this system demonstrate that hANP is reliably measured even without prior extraction.

Antibody Specificity↗
PubMed1986

[Rhabdomyolysis as a complication of chronic alcoholism. Observations in 19 cases].

In 19 chronic alcoholics with rhabdomyolysis the clinical picture demonstrated markedly different degrees of severity of myolysis. Muscle pain, muscle swellings and brown-coloured urine were rare. But symptoms of delirium, at times with cerebral seizures, were frequent at the onset. Renal failure of different degrees was common; five patients had to be dialysed. Two patients died in irreversible shock. Respiratory insufficiency and hypercalcaemia were other complications. Early recognition of the disease is important, because early treatment can prevent acute "myoglobinuric" renal failure.

Adult↗
PubMed1986

Yeast alpha-factor and somatostatin enhance binding of [3H]estradiol to proteins in rat pancreas and Saccharomyces cerevisiae.

Pancreatic tissue contains an [3H]estradiol-binding protein that requires a coligand in the steroid-binding reaction. The endogenous coligand appears to be the tetradecapeptide somatostatin. Yeast alpha-factor, a tridecapeptide pheromone that induces conjugation between haploid cells of opposite mating type, was found to be as effective as somatostatin in enhancing specific binding of [3H]estradiol to partially purified pancreatic protein. Supernatant fractions from yeast cells also contain an [3H]estradiol-binding protein. alpha-Factor can enhance specific binding of [3H]estradiol to such yeast fractions. Somatostatin, somatostatin analogues, and an analogue of alpha-factor enhanced binding of [3H]estradiol but did not inhibit cell growth or induce morphological changes in S. cerevisiae. Thus, it appears that coligand-requiring [3H]estradiol-binding activity and mating in yeast are not directly related.

Amino Acid Sequence↗