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Biomedical subjects

K A Neftel

Publications and source records attributed to K A Neftel.

45 records · Page 3Linked to original sources
PubMed1983

Radial segmentation of nuclei (Rieder cells): a morphological marker of T-cell neoplasms?

Pretreatment blood smears of adult patients with acute lymphoblastic leukemia were examined for neoplastic cells showing nuclear radial segmentation (RS). RS was present in 6 of 7 patients with immunologically proven T-cell leukemia, but not in 11 patients whose leukemic cells lacked T-cell markers. Electron microscopic studies of neoplastic cells showed multiple nuclear indentations and abundant cytoplasmic microfilaments and microtubuli in connection with pericentriolar dense material. RS formation was decreased in 1 patient after chemotherapy with a vincristine-containing regimen, while the white cell count remained unchanged. Radial segmentation (RS) of leukocyte nuclei is a well-known phenomenon, which is observed ex vivo (Rieder cells), and can be induced in vitro. Convoluted or multilobulated nuclei in lymphoid neoplasms are similar to RS nuclei both with regard to their structure and their sensitivity to spindle-blocking drugs. We propose that the nuclear alterations observed in a variety of different T-cell neoplasms are identical with RS, and suggest that RS might be a morphological marker for subsets of lymphoproliferative disorders of T-cell origin.

Adult↗
PubMed1982

Effect of storage of penicillin-G solutions on sensitisation to penicillin-G after intravenous administration.

Intravenous administration of a total dose of more than 200 million IU of penicillin-G led to sensitisation of lymphocytes and formation of specific anti-penicilloyl antibodies of the IgG class. These effects were prevented when the penicillin solution used was freshly prepared and given as a bolus rather than as a slow infusion. The causative antigens seem to be related not to penicilloylated high molecular weight impurities in the penicillin preparations, but to the degradation and/or transformation products of penicillin-G that form when the drug is in solution even if only for a few hours, and not only at room temperature but also at 4 degrees C. Thus penicillin solutions should be freshly prepared and administered from vials containing less than 10 million IU so that bolus doses can be given.

Adult↗
PubMed1982

Stage fright in musicians: a model illustrating the effect of beta blockers.

Stage fright was used to investigate the mode of action of beta blockers in acute anxiety and on the technical-motor performance of 22 performing string players. They received 100 mg of atenolol or placebo 6.5 hr before performing either in the presence or absence of an audience. Continuous heart rate, stage fright (especially devised rating scale), technical-motor performance (runs of fast notes, trills, vibratos), and urine catecholamine levels were assessed. Before an audience the placebo group showed a significant impairment of technical-motor performance (increase in the relative variance of repeated fast elements of movements: + 25.68%, p less than 0.01) as compared to performance with no audience present; there was a slight but not significant improvement under beta blockade (- 7.48%). Heart rate was significantly lower under beta blockade than under placebo (p less than 0.001). Urine catecholamine levels increased twice as much under beta blockade as under placebo before an audience (p less than 0.01). Beta blockade did not influence stage fright measured before performing, but reduced it (measured immediately after the concert) during the concert. We conclude that the drug was at least partially effective as shown by an improvement in technical-motor performance, and that the beneficial effects of beta blockade in stage fright only involve a peripheral site of action.

Adrenergic beta-Antagonists↗
PubMed1982

Misleading supine chest X-ray in complete detachment of a Starr-Edwards prosthetic aortic valve.

The authors report a case of total detachment of a Starr-Edwards aortic valve prosthesis occurring eleven years after implantation. The detached valve had embolized into the descending thoracic aorta. The prosthetic valve was projected into an apparently normal position on a supine chest X-ray. The correct diagnosis was thus delayed. The authors stress the importance of obtaining lateral views or performing fluoroscopy and/or echocardiography in the emergency room in patients with acute chest symptoms after heart valve replacement.

Aortic Valve↗
PubMed1981

Neutropenia after penicillins: toxic or immune-mediated?

Eight patients treated with a total of 220-550 million U penicillin-G developed neutropenia. These cases have been compared with eight patients receiving a similar dose of pencillin-G with no adverse reactions and with eight untreated subjects. All penicillin-treated patients showed raised levels of anti-IgG antibodies and lymphocyte culture stimulation indices. These values were highest in the neutropenia group. Both of the two tests significantly discriminated the three groups. Antineutrophil antibodies could be detected in four of seven neutropenic patients with a staphylococcal-slide-assay while indirect immunofluorescence and microcytotoxicity tests failed to reveal these antibodies. The literature dealing with neutropenias induced by penicillin-G and its congeners is reviewed. We conclude that (1) penicillin-G in doses exceeding a total of 200 million U frequently induces neutropenia, (2) an immune-mediated pathogenesis a highly probable, (3) neutropenia after penicillins is different from two hither-to accepted types of this side effect, (4) sufficiently high amounts of penicillin-G intravenously always induce sensitization against this drug.

Adolescent↗
PubMed1981

Heat-induced radial segmentation of leucocyte nuclei: a non-specific phenomenon accompanying inflammatory and necrotizing diseases.

Heat-induced radial segmentation (RS) of leucocyte nuclei in vitro (2 h at 41 degrees C) is a heretofore unknown phenomenon, accompanying inflammatory and necrotizing diseases. This phenomenon appears to be identical with the known oxalate-induced radial segmentation and is caused by contractile microfilaments and microtubuli radiating from the centriole. Preincubation of washed leucocytes from healthy donors with plasma of patients showing the phenomenon of RS did not induce RS and preincubation of washed RS-leucocytes with normal plasma did not suppress RS. RS, however, could be induced by intravenous endotoxin injection in a healthy volunteer and could be prevented in part by addition of Vincristine to the blood samples. The phenomenon corresponds to an incomplete, heat-inducible amitosis. The cause of the thermolability of the mitotic apparatus in various diseases remains unclear.

Bacterial Infections↗
PubMedDate not supplied

HIV-reverse transcriptase and human DNA polymerase alpha share amino acid sequence homologies to bacterial penicillin-binding proteins.

Penicillin-binding proteins are the specific targets for the beta-lactam antibiotics. Recently it was observed that beta-lactam antibiotics also have targets in proliferating eukaryotic cells (1), one of which most likely is the replicative DNA polymerase alpha. Here we show that HIV-reverse transcriptase and human DNA polymerase alpha share amino acid sequence homologies to five bacterial penicillin-binding proteins.

Amino Acid Sequence↗