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Biomedical subjects

R H Johnson

Publications and source records attributed to R H Johnson.

At least 145 records · Page 8Linked to original sources
PubMed1979

Comparative trial of valproate sodium and clonazepam in chronic epilepsy.

A crossover comparative study of valproate sodium and clonazepam in the treatment of 32 adult epileptic patients receiving multiple drug therapy is described. Serum concentrations of other anticonvulsant drugs were unchanged by the addition of clonazepam. However, patients receiving high doses of other anticonvulsant drugs had lower serum concentrations of clonazepam (p less than .01). With valproate sodium, phenobarbital concentrations increased (P less than .05) in patients receiving phenobarbital but not significantly in patients receiving primidone. Phenytoin concentrations were reduced (P less than .05) during treatment with valproate sodium. Both drugs significantly reduced the frequency of minor seizures, with valproate sodium having the greater effect. However, it is important to monitor serum concentrations of other anticonvulsant drugs during treatment with valproate sodium since changes in these may influence seizure control or cause side effects.

Adult↗
PubMed1979

A review of chemotherapeutic plaque control.

Of the plaque-control agents studied, it would appear that chlorhexidine is the most suitable agent to prevent plaque accumulation and the development of gingivitis. It also is attractive to speculate on the possibilities of a commercially available mouthwash. A trio of antibiotics--kanamycin, spiramycin, and vancomycin--may prove of value in the treatment of severe gingival and periodontal disease. The ultimate role of xylitol has yet to be determined. Regardless of the agent selected, access to the gingival sulcus region seems critical.

Anti-Bacterial Agents↗
PubMed1979

The effect of somatostatin on metabolic and hormonal changes during and after exercise.

The effect of intravenous somatostatin on blood levels of metabolites and hormones has been examined in normal subjects who performed a 30-minute period of bicycle exercises at 70% maximal exercise capacity. The results have been compared with control studies in the same subjects. Measurements were made of blood levels of lactate, glucose, free fatty acids, glycerol, acetoacetate, 3-hydroxybutyrate, insulin, glucagon, growth hormone (hGH) and prolactin. Growth hormone and glucagon release were suppressed during exercise with somatostatin and there was a subsequent elevation during recovery. There was slight post-exercise depression of insulin, but no alteration of plasma prolactin secretion. Blood glucose was reduced during exercise with somatostatin and increased during recovery. The elevation of ketone bodies after exercise was greater in the investigation with somatostatin, but there were no significant changes in other metabolites. Somatostatin, although causing inhibition of hGH release, appeared to have no significant effect upon fatty acid mobilization during exercise.

Adult↗
PubMed1979

Purification and immunobiological properties of R antigen and its relation to M protein of type 3 group A Streptococcus.

R protein was extracted from type 3 group A streptococci with hot (95 degrees C) HCl and was purified by ammonium sulfate precipitation followed by molecular-sieve and ion exchange chromatography. Although the R3 antigen was present in a heterogeneous population of proteins ranging from 78,000 to 100,000 daltons in size, we were able to separate an R-rich fraction that contained minimal amounts of heterogeneous proteins as indicated by electrophoresis in sodium dodecyl sulfate-polyacrylamide gels. The final yield of the purified R protein was approximately 15 mug (dry weight) per g (wet weight) of washed and sedimented streptococci. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis indicated a molecular size of approximately 78,000 daltons. Amino acid analysis showed lysine, glutamic acid, alanine, and aspartic acid as the predominant amino acids. A detailed comparison of the purified R3 protein with type 3 M protein indicated a similarity in composition and order of frequency of amino acids. However, the R3 antigen was found to be distinctive from the M3 antigen in agar gel diffusion tests. In addition, R3 and M3 proteins behaved differently in opsonophagocytosis tests and opsonization inhibition tests. Thus, R3 and M3 proteins produced precipitin lines of nonidentity with an unabsorbed antiserum against whole type 3 streptococci: M3-specific antiserum, but not R3-specific antiserum, enhanced the phagocytosis of type 3 streptococci. Purified M3 but not R3 protein was capable of inhibiting the type-specific opsonization of type 3 streptococci. The physicochemical resemblance between M and R proteins in general suggests a common genetic origin. Perhaps R proteins are variant forms of M proteins from which the antiopsonic determinant has been deleted.

Amino Acids↗
PubMed1979

Diagnosis of miliary tuberculosis by cerebral computerized tomography.

We report a case of miliary tuberculosis with symptoms and signs of an intracranial mass. These were found to be multiple tuberculomas by computerized axial tomography (CT scan). We review the pathophysiologic features of intracranial tuberculomas. The CT scan allows a rapid and sensitive diagnosis of intracranial tuberculosis without utilizing invasive neurodiagnostic techniques. The value of using CT scans following treatment was confirmed.

Adult↗
PubMed1979

In vitro response of lymphocytes of normal and ovine squamous cell carcinoma-bearing sheep to phytomitogens and tumour extracts.

A comparison was made of the blastogenic responses of peripheral lymphocytes (BRPL) of normal sheep with those of sheep bearing ovine squamous cell carcinoma (OSCC). In normal tumour-free sheep, BRPL to phytomitogens were found to vary in different age groups, and BRPL to OSCC extracts were found to become significantly elevated in sheep over one year old. In tumour-bearing mature sheep, BRPL to phytomitogens and to OSCC extracts decreased significantly with increasing maturity of tumours. The results are interpreted to show that increasing tumour volume, due to natural growth or enhancement, associates with increasing suppression of cell-mediated responses, and that such suppression may be a cause and a result of increased tumour volume.

Age Factors↗
PubMed1979

Effect of removal of ovine squamous cell carcinoma on peripheral lymphocyte stimulation by tumour extracts and phytohaemagglutinin.

Mock-operation of normal tumour-free sheep was not associated with significant changes in blastogenic responses of peripheral lymphocytes (BRPL) to phytohaemagglutinin (PHA-P) or tumour extracts (TA). In age-matched tumour-bearing sheep, tumour removal was associated with a significant prolonged increase in BRPL to PHA-P and TA about three weeks after operation. This increase was significantly greater in sheep with mature than with early tumours. No increase in BRPL occurred in sheep with secondary lesions. Challenge of tumour-removed sheep with TA 15 weeks after operation was associated with a significant anamnestic-type short-term surge in BRPL to PHA-P and TA, which was significantly greater in sheep which had previously borne advanced tumours. Mock-operated normal mature sheep challenged with TA also showed a lowgrade anamnestic-type response of BRPL to PHA-P and TA. The results are discussed in terms of the mechanisms of BRPL suppression, and of specific reactions in normal sheep.

Animals↗
PubMed1979

Effect of cyclophosphamide on tumour growth and cell-mediated immunity in sheep with ovine squamous cell carcinoma.

Cyclophosphamide (CY) is shown to associate with partial or complete regression of ovine squamous cell carcinoma (OSCC), the rate of regression varying directly with CY dosage and inversely with maturity of tumour at the start of therapy. CY treatment given coincidental with injection of tumour extracts (TA) completely neutralised the tumour enhancement effects regularly associated with TA injections, and caused tumour regression comparable to that seen in sheep treated with CY alone. In discussion of the results, which incorporate parallel studies on cell-mediated responses, it is suggested that immunosuppression during tumour growth is due to formation of B suppressor lymphocytes and that CY treatment of OSCC may exert beneficial effects through its immunosuppressive action on such lymphocytes as much as its direct cytotoxic action on tumour cells.

Animals↗
PubMed1979

Suppression of blastogenic response of peripheral lymphocytes by serum from ovine squamous cell carcinoma bearing sheep.

Sera from sheep with ovine squamous cell carcinoma are shown to contain a factor which nonspecifically inhibits blastogenesis of T lymphocytes. This blastogenic inhibitor is stable at 56 degrees C for 30 min, passes a 430 nm filter, and increases in concentration (or efficiency) with increasing tumour volume. Tumour removal is associated with effective circulatory disappearance of the inhibitor and coincides with recovery of cell-mediated responses within five weeks. The inhibitor adsorbs readily to leucocyte populations from normal and tumour removed sheep. It is suggested that the blastogenic inhibitor is mediated by the tumour to cause immunosuppression through an undetermined B lymphocyte suppressor pathway, and acts as a mechanism protecting the tumour from immune rejection by T lymphocytes.

Animals↗
PubMed1978

Metastatic phycomycosis in a horse.

Extensive subcutaneous phycomycosis of the lower hindlimb developed over a period of 8 months in a Thoroughbred filly. There was no response to treatments such as trichlorphon, sodium iodide, or etisazole. Extension of the limb lesion over the following 3 months was associated with an enlarged inguinal lymph node, which was removed. Characteristic phycomycotic lesions were observed in the node, and a fungus having the morphologic features of Hyphomyces destruens was isolated from both the limb and nodal lesions.

Animals↗
PubMed1978

Growth hormone, prolactin, and corticosteroid responses to insulin hypoglycaemia in alcoholics.

Plasma growth hormone (GH), prolactin, and corticosteroid responses to insulin-induced hypoglycaemia were studied in 24 men with progressive alcoholism who had been abstinent for two to seven days. Ten normal healthy subjects (five men, five women) served as controls for comparing GH and prolactin responses, while cortisol responses were studied in a further six male controls. Blood samples were taken at intervals after an injection of soluble insulin (0.1 U/kg body weight). All patients developed adequate hypoglycaemia (blood glucose <2.2 mmol/l (<39.6 mg/100 ml)) and nine had impaired GH responses (peak concentration <10 mU/1). Prolactin concentrations fell or remained unchanged in nine patients, eight of whom also had impaired GH responses. In seven patients corticosteroid concentrations decreased from basal concentrations, and six of these patients had impaired GH responses. All three hormone responses were impaired in several patients, and significant correlations were found between the GH and prolactin responses at 45 and 60 minutes. GH response was not correlated with age, duration of drinking, duration of alcoholism, or admitted alcohol intake. GH responses were significantly lower in patients who had the most severe withdrawal symptoms. Our observations of impaired stress responses in some recently abstinent alcoholics may have important implications for the management of alcohol withdrawal syndrome.

Adrenal Cortex Hormones↗