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Biomedical subjects

J A Gordon

Publications and source records attributed to J A Gordon.

At least 19 recordsLinked to original sources
PubMed1992

Thrombotic microangiopathy: a case report and review of the literature.

Thrombotic microangiopathy most likely represents a spectrum of diseases consisting of multiple etiologies that has a final common pathway of multiorgan microvascular thrombosis. The variable responses to several different modes of therapy would suggest that more than one pathogenetic mechanism is involved. Untreated, it has been associated with very high morbidity and mortality rates. A poor understanding of the basic disease process has prevented specific treatment modalities, although early diagnosis and availability of dialysis and blood product transfusion services remain crucial. Several modes of therapy have been used to date, with plasma exchange being the most effective method studied and shown to improve survival. On the basis of current knowledge, this form of treatment should be instituted promptly in severe cases. Anecdotal reports of recovery with vincristine or IgG alone or with the use of IgG after the apparent failure of plasma therapy appear promising and deserve further investigation as initial therapeutic measures used in thrombotic microangiopathy. Although the majority of patients recover with normal renal function, those with severe thrombotic microangiopathy may heal through sclerosis with residual hypertension and chronic renal impairment requiring continual medical therapy.

Adult↗
PubMed1979

The role of concanavalin A dissociation on positive cooperativity of binding with native and fixed erythrocytes.

Positive cooperativity demonstrated by Scatchard plot analysis of concanavalin A (con A) binding was found with native or glutaraldehyde-fixed erythrocytes. This suggests that factors other than membrane changes might be involved in the apparent increase in receptor binding affinity with increasing site occupancy. The elution pattern of 125I-con A chromatographed on Bio-Gel P-150 with decreasing concentration showed a drop in average molecular weight compatible with con A dissociation to dimers, protomers, and protomer fragments. Similarly, the per cent of 125I-con A specifically binding to Sephadex G-75 fell with decreasing concentration of con A applied. The inclusion of unlabeled carrier con A suppressed the dissociation of labeled con A in Bio-Gel P-150 and increased the per cent binding to Sephadex G-75. Both labeled and unlabeled con A were multibanded in sodium dodecyl sulfate-polyacrylamide gel electrophoresis. As previously reported, the three major bands are consistent with intact protomer (approximately 25,000 daltons) and two fragments (approximately 13,000 and 10,000 daltons) with minor bands representing undissociated species. These observations indicate that there is a concentration-dependent association of Con A subunits which contribute to the observed positive cooperativity of con A binding to erythrocytes.

Binding Sites↗
PubMed1979

Delayed extrusion of testicular prosthesis.

A case of migration and extrusion of a testicular prosthesis with erosion of the fixation tab through the skin is reported. Predisposing factors are discussed. Trimming the corners of the tab prior to fixation is recommended as well as anchoring it firmly to the most dependent portion of the scrotum, using nonabsorbable sutures.

Adolescent↗
PubMed1978

Testosterone rebound therapy: a neglected modality.

A summary of the literature and a 20-year review of our own experience with testosterone rebound therapy is presented. Of 225 patients followed, 52% rebounded to fertile levels followed by pregnancy in the wives of 25%. Pregnancy occurred in 3 wives (8%) of the 38 initially azoospermic patients. There was only a 4% incidence of failure to return to at least the pretreatment sperm count following therapy, and no persistent azoospermia was observed. These results are consistent with other recent reports of several large series of patients. Proper screening and selection of patients is mandatory. Testosterone rebound is a neglected form of therapy meriting consideration in selected patients.

Cell Count↗
PubMed1978

Evaluation of stricture formation as a complication of vasopuncture and vasography in the guinea pig.

Stricture formation at the site of injection for vasography has been observed clinically. An animal model was developed to evaluate this occurrence. Bilateral vasopuncture with a 25-gauge needle was carried out in 25 male guinea pigs. The sites of vas punture were marked with tantalum clips in the perivasal tissue. The left-sided vasa were injected with contrast material and the right sides with normal saline. These 50 vasa were evaluated for radiographic and histologic evidence of inflammation and stenosis 3 months following injection. Ninety-four per cent of the 50 vasa studied showed no significant stenosis. Those vasa exhibiting obstruction were in the first four animals studied, with no correlation as to which material was injected. This finding implicates technical factors as a cause for these results. In the guinea pig, vasopuncture with a fine-gauge needle and meticulous technique does not result in a significant rate of stenosis regardless of the medium injected.

Animals↗
PubMed1977

Casualty evacuation in the Rhodesian terrorist war.

The involvement of the Rhodesian Medical Association in providing medical services to both the troops and the African clinics because of the terrorist war is described. Experiences in the handling and evacuation of casualties by air or road are described, and immediate emergency measures are mentioned. Measures taken to meet a possible escalation of the conflict are reported.

Acute Disease↗
PubMed1976

Receptor distribution and the mechanism of enhanced erythrocyte agglutination by soybean agglutinin.

We have examined the role of receptor clustering in intact erythrocyte membranes exhibiting enhanced lectin-mediated cell agglutination by analyzing freeze-fracture and freeze-etch images of human erythrocytes labeled with ferritin-conjugated soybean agglutinin. We find that trypsinization and fixation of intact erythrocytes, in either order, causes no alteration of the random distribution of ferritin-conjugated soybean agglutinin on the surfaces of these cells as compared to their distribution on the surfaces of fixed erythrocytes and untreated erythrocyte ghosts. Furthermore, clustering of the intramembranous particles in the membrane of intact erythrocytes was not found with any of the cells described above. We conclude that clustering of the soybean agglutinin receptors is not a major factor involved in the enhanced agglutination of intact trypsinized erythrocytes. Caution is necessary in transferring information obtained with erythrocyte ghosts, where clustering can be induced, to intact erythrocytes.

Agglutinins↗