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Biomedical subjects

A Keynan

Publications and source records attributed to A Keynan.

At least 55 records · Page 3Linked to original sources
PubMed1983

Multiple autoimmune manifestations in a splenectomized subject with HLA-B8.

Idiopathic thrombocytopenic purpura developed in a 31-year-old man, and he underwent a splenectomy because of his failure to respond to steroid therapy. Subsequently, during a six-year follow-up, chronic active hepatitis, Coombs' positive hemolytic anemia, and pulmonary interstitial fibrosis developed. Since such a clustering of autoimmune manifestations in a single subject is unusual, possible contributing factors were sought. We suggest that both the splenectomy and the histocompatibility antigen HLA-B8, which the patient was found to carry, may have contributed to this rare clinical syndrome.

Adult↗
PubMed1982

The erythrocyte membrane in essential hypertension. Modified temperature-dependence of Li+ efflux.

The rate of ouabain-resistant Li+-efflux was studied in erythrocytes of normal controls and of patients with essential hypertension. Despite variability in rate, erythrocytes from normotensive persons revealed a uniform pattern of temperature dependence of the efflux, with two slopes (K = 9.4 and 19.1 kcal/mol, respectively) and a transition at about 25 degrees C. Erythrocytes from the patients showed both a higher rate of Li+ efflux and significant changes in the temperature response, with essentially a single slope (Ka = 14 kcal/mol). The data indicate localized changes in the membrane organization of hypertensive erythrocytes, involving lipid-protein interaction.

Acetylcholinesterase↗
PubMed1982

Angiographic diagnosis and treatment of hemobilia.

Hemobilia (bleeding from the biliary tract) may be secondary to trauma, inflammatory disorders, gallstones, or tumor. Although it used to be rare, it is becoming more frequent due to trauma, including iatrogenic causes. The etiology is established by selective angiography, which also facilitates embolic occlusion of the arterial branches supplying the lesion. Nonsurgical control is preferable to surgical management. Two cases are reported, emphasizing the etiologic and therapeutic aspects of interventional studies of the liver.

Adult↗
PubMed1981

Cell wall synthesis and initiation of deoxyribonucleic acid replication in Bacillus subtilis.

We have observed a connection between cell wall synthesis and the initiation of chromosome replication in Bacillus subtilis. Initiation of chromosome replication was prevented in synchronous cultures in the presence of the cell wall synthesis inhibitor vancomycin. When vancomycin was added to the cultures after initiation of chromosome replication, one round of replication was completed but no reinitiation occurred. Similar results were obtained when cell wall synthesis was inhibited by ristocetin, cycloserine, cloxacillin, or cephaloridine. When sucrose was added to the medium, initiation of deoxyribonucleic acid replication occurred in the presence of vancomycin, to an extent which allowed replication of no more than approximately one-half of the deoxyribonucleic acid of the culture. The same was found in cultures of spheroplasts of B. subtilis. However, initiation of chromosome replication in spheroplasts was completely insensitive to cloxacillin.

Bacillus subtilis↗
PubMed1980

Immunological studies in angioimmunoblastic lymphadenopathy.

Immunological studies were carried out on two female patients with angioimmunoblastic lymphadenopathy (AIL). Both presented with fever, lymphadenopathy, hepatosplenomegaly, rash and apparent ampicillin hypersensitivity. During the active phase of the disease, cellular immunity was depressed and T cell blastogenesis induced by lectins was abnormal. In the first patient, a non-dialysable plasma factor was found that inhibited normal lymphocyte blastogenesis, the removal of which enhanced the activation of AIL lymphocytes. This inhibitory plasma factor was also observed in the second patient during relapse of the disease. The latter patient responded well to steroid and levamisole therapy, showing clinical remission and a return of in vivo and in vitro parameters of cellular immunity. Defective B cell regulation due to impaired suppressor function, followed by immunoglobulin overproduction, is suggested to occur in AIL.

Adolescent↗
PubMed1980

Sodium transport in red cells of patients with acute viral hepatitis.

The red blood cell composition was determined in 25 patients with acute viral hepatitis and in 26 normal subjects. The potassium concentration was 83.4 +/- 4.11 mmol/kg red cells (mean +/- SD) in hepatitis red blood cells and 79.7 +/- 4.74 mmol/kg red cells in the control samples (P < 0.005). There were no significant differences between the sodium content of normal and hepatitis red blood cells. 22Na-Efflux was determined in red blood cells of 17 patients with acute viral hepatitis and 18 normal subjects. The mean sodium efflux rate constant was 0.212 +/- 0.036 in red cells of patients with hepatitis and 0.295 +/- 0.046 in the control samples (P < 0.001). This difference resulted from a reduction in both the active and residual portions of the red blood cell sodium pump in the patients with viral hepatitis. Red blood cells of patients with acute viral hepatitis accumulated sodium at a significantly slower rate than normal red blood cells. The increase in osmotic fragility after 24 hr incubation at 37 degrees C in the absence of glucose was less prominent in hepatitis red blood cells than in normals. The findings of a reduced sodium efflux and slower accumulation of sodium during incubation, suggest that red blood cells from patients with viral hepatitis are less permeable to sodium, thereby leading to a new steady-state, characterized by a reduced sodium efflux.

Adolescent↗
PubMed1979

Changes in sporulation potential during the growth cycle of Bacillus subtilis.

The sporulation potential of Bacillus subtilis as a function of position in the cell cycle was determined by transferring cells from growth medium to sporulation medium at various times during growth. Growth was induced by incubating heat-activated spores in rich medium or by diluting stationary phase vegetative cultures with fresh growth medium. The results supported earlier observations that sporulation potential is cell cycle dependent. The rise in sporulation potential was studied by exposing cultures to the inhibitors of cell wall and protein synthesis, vancomycin and chloramphenicol. The delay in the appearance of the peak of sporulation potential caused by these inhibitors compared with the reported lack of effect of nalidixic acid, indicates that the appearance of sporulation potential requires synthesis of a macromolecular component other than deoxyribonucleic acid. The effect of nalidixic acid in preventing the decline of the sporulation potential was compared with the effect of high temperature on a mutant temperature sensitive for the initiation of DNA replication. It was found that prevention of chromosome completion with nalidixic acid maintained a high sporulation potential, whereas prevention of chromosome re-initiation in the temperature sensitive mutant did not affect the decline in sporulation potential as the cells enter stationary phase.

Bacillus subtilis↗
PubMed1979

Specific inhibition of outgrowth of Bacillus subtilis spores by novobiocin.

Spores of a Bacillus subtilis mutant temperature sensitive in deoxyribonucleic acid (DNA) replication proceeded through outgrowth at the nonpermissive temperature to the same extent as the wild-type parent spores. In contrast, the DNA synthesis inhibitor novobiocin completely prevented spore outgrowth while displaying a marginal effect on logarithmic growth during one generation time. Inhibition of outgrowth by novobiocin occurred in the absence of DNA replication, as demonstrated in an experiment with spores of the temperature-sensitive DNA synthesis mutant at the restrictive temperature. Novobiocin inhibited the initial rate of ribonucleic acid synthesis to the same extent in germinated spores and in exponentially growing cells. A novobiocin-resistant mutant underwent normal outgrowth in the presence of novobiocin. Therefore, novobiocin inhibition was independent of its effect on chromosome replication per se.

Bacillus subtilis↗
PubMed1979

Cat-scratch disease presenting as status epilepticus. A case report.

A 12-year-old Bedouin boy presented with sudden asymmetrical status epilepticus. The presence of a scalp wound, rubbery cervical lymphadenopathy and a history of contact with cats suggested the diagnosis of cat-scratch disease complicated by encephalopathy. The diagnosis was supported by histological examination of a cervical lymph node and a positive skin test with cat-scratch antigen. The rapid establishment of the diagnosis avoided the necessity of elaborate and complicated neuroradiological investigations.

Cat-Scratch Disease↗
PubMed1978

Independence of Bacillus subtilis spore outgrowth from DNA synthesis.

The outgrowth of spores of Bacillus subtilis 168 proceeded normally in temperature-sensitive DNA mutants under restrictive conditions and in the absence of DNA synthesis. Two inhibitors of DNA synthesis, nalidoxic acid and 6-(p-hydroxyphenylazo)-uracil, inhibited spore outgrowth under some nutritional conditions; this inhibition of outgrowth however, though not that of DNA synthesis, could be reversed by glucose. The sensitivity of the outgrowing spores to nalidixic acid and 6-(p-hydroxyphenylazo)-uracil inhbition decreased as a function of outgrowth time. The cells became completely resistant to the inhibitors after 90 min. The development of this resistance occurred also in the absence of DNA synthesis. It was concluded that DNA synthesis is not needed for spore outgrowth, and that outgrowing cells and vegetative cells differ in their sensitivity to these inhibitors.

Bacillus subtilis↗