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Biomedical subjects

R H Johnson

Publications and source records attributed to R H Johnson.

At least 127 records · Page 7Linked to original sources
PubMed1981

A simple procedure to obtain continuous cell lines from bovine peripheral blood leucocytes.

A method is described by which cell lines can be readily developed from bovine peripheral leucocytes. Fifteen cell lines have been developed from 25 attempts, passage levels up to 60 being reached. The cell lines are aneuploid and predominantly epithelial, show split ratio capabilities of 1:4 to give monolayers with 5 days of routine passage, and have high resistance to laboratory contamination with bacterial and fungal agents. Data are given concerning establishment, morphology, viral susceptibility and chromosomal counts of established cell lines.

Animals↗
PubMed1981

Role of sensory nerves in the cardiovascular and respiratory changes with isometric forearm exercise in man.

1. To investigate the stimulus to the cardiovascular and respiratory systems during isometric exercise, two patients with sensory neuropathies affecting forearm afferent nerves were studied and their circulatory and respiratory responses compared with those of normal subjects. The contribution of pain to the cardiorespiratory changes was also investigated in normal subjects by using hypnosis to relieve pain during and after isometric exercise. 2. The patients and normal subjects performed fatiguing isometric forearm exercises on a handgrip dynamometer on at least two occasions, once with normal forearm circulation and once with the forearm circulation occluded by an arterial cuff during and after exercise. Blood pressure, heart rate, minute ventilation, oxygen consumption and ventilatory equivalent were measured before, during and after exercise. 3. During exercises with and without occlusion increases in blood pressure and heart rate in patients and in subjects under hypnosis were similar to those in control subjects. Changes in oxygen consumption were also similar to those of controls, but the patients showed a smaller rise in ventilation and no increase in ventilatory equivalent. 4. After exercise in normal subjects occlusion of the forearm circulation produced continued elevation of blood pressure and respiration. Blood pressure also remained elevated after exercise with occlusion in subjects under hypnosis, but not in patients with sensory loss. Respiration did not remain elevated in either subjects under hypnosis or patients. 5. The results suggest that cardiovascular and respiratory changes during isometric exercise can occur without involvement of muscle sensory nerves and that pain contributes substantially to the increase in respiration. Normal sensory innervation is apparently necessary only for maintenance of raised blood pressure after exercise with occlusion.

Adolescent↗
PubMed1981

Comparison of sodium valproate and phenytoin as single drug treatment in epilepsy.

Thirty-three epileptic patients were randomly divided into two treatment groups. One group of 18 patients was given sodium valproate; the other 15 patients were given phenytoin. Periods of treatment ranged from 9 t0 48 months (mean, 30 months). Any patient who developed a seizure while on the first drug was changed to the other drug, provided the serum level of the first drug was in the accepted therapeutic range. Six required the change from phenytoin to sodium valproate, and three from sodium valproate to phenytoin. Side effects were not a major problem with either drug during the trial period. Phenytoin has been widely prescribed alone; our results indicate that sodium valproate may also be used as a single drug in the treatment of several types of epilepsy.

Adolescent↗
PubMed1981

The effects of phenytoin on phenobarbitone and primidone metabolism.

Serum concentrations of primidone and its metabolites-phenobarbitone and phenylethylmalonamide-were measured in 40 epileptic patients receiving treatment with primidone alone or primidone plus phenytoin. Serum phenobarbitone concentrations were also measured in 100 patients receiving phenobarbitone, alone or with phenytoin showed raised serum phenobarbitone concentrations. Phenytoin also caused raised phenylethylmalonamide concentrations in patients on primidone.

Adult↗
PubMed1981

The management of patients with metastatic cancer from an unknown primary site.

The authors outlined their management of patients with known or suspected metastatic cancer from an unknown primary site. Patients with disease in regional lymph nodes should receive thorough evaluation of sites that drain primarily to those nodes. If the primary site is not located, the node should be biopsied in a manner that allows node dissection if this proves to be indicated. A significant number of these patients will be cured or receive significant palliation. In patients with disseminated disease, an effort should be made to quickly determine whether the tumor is one for which specific treatment is available. There is nothing to be gained by conducting extensive evaluation to locate the primary site if the treatment will not be affected by this knowledge.

Biopsy↗
PubMed1981

Sample size for detection of Y-chromosomes in lymphocytes of possible freemartins.

The number of metaphases that need to be examined to detect a Y-chromosome in a lymphocyte of a possible freemartin with a prescribed degree of certainty depends on the distribution of % XY cells among freemartins. To quantify this, the beta-binomial distribution was fit by maximum likelihood to% XY cells observed in blood samples of 70 freemartins (twin births only). The estimate mean and standard deviation of XY cells frequency in 70 freemartins (12,885 metaphases) was 0.48 and 0.30, respectively. These estimates correspond to a U-shaped distribution of XY cell frequency, i.e., one in which either an XX or an XY cell type predominates in most freemartins. These values indicate that sample sized of 26 and 168 are required to by 95% and 99% confident, respectively, that a female co-twin will not be misclassified.

Animals↗
PubMed1981

Colorimetric determination of disulfiram in tablets: collaborative study.

The colorimetric reaction of cuprous iodide and disulfiram has been collaboratively studied in 8 laboratories to determine the drug in tablet form at 2 dosage levels. The disulfiram was extracted from the tablet matrix with methylene chloride. After a basic wash with 1 M NaOH, an aliquot of the methylene chloride solution was reacted with solid cuprous iodide, and the absorbance of the resulting color was measured. Single assays on 2 synthetic preparations of known disulfiram content were performed with average recoveries of 98.4 and 99.2% for 93.3 and 105.3 mg, respectively. Duplicate determinations on 2 commercial tablet preparations declared at 250 and 500 mg gave mean and standard deviation values of 246.6 +/- 6.40 and 493.6 +/- 12.0 mg, respectively. The results agreed closely with those obtained by the author using the NF iodometric titration procedure. The method has been adopted official first action.

Chromatography, Thin Layer↗
PubMed1980

Evidence of vagal neuropathy in chronic alcoholics.

Autonomic function was tested in healthy control subjects and 20 chronic alcoholic patients with varying degrees of alcohol-related peripheral and central neurological damage. The alcoholics were divided into two groups according to the severity of their symptoms and signs. The alcoholic subjects had no postural hypotension. However, heart-rate responses to Valsalva's manoeuvre, deep breathing, change in posture, baroreceptor stimulation, and atropine were lower in those alcoholics with a greater degree of peripheral and central nervous damage than in the less severely affected alcoholics and the controls. These results suggest that chronic vagal damage may be a feature of alcoholic polyneuropathy.

Adult↗
PubMed1980

The role of folate deficiency in the development of peripheral neuropathy caused by anticonvulsants.

To investigate the role of folate deficiency in neuropathy caused by anticonvulsants, electrophysiological studies of peripheral nerve function were carried out on 29 epileptic patients on long-term anticonvulsant therapy. All but three patients showed abnormalities in one or more electrophysiological measurements, the main abnormality being in amplitude of sensory nerve action potential--this was reduced or absent in 76% of patients. All patients had low concentrations of folate in serum and CSF, these being below the normal ranges in 19 patients. These 19 patients were treated with folate, either 5-formyltetrahydrofolate (10 patients) or folic acid (9 patients), over a period of one month. After therapy all patients had normal levels of folate in serum and CSF, slightly higher levels in CSF being obtained in those receiving 5-formyltetrahydrofolate. Folate therapy significantly reversed abnormalities in motor and sensory nerve distal latencies; the effect was greater with 5-formyltetrahydrofolate, apparently because this produced higher CSF folate concentrations than folic acid. We conclude that folate deficiency may be involved in the development of peripheral neuropathy due to anticonvulsants.

Adult↗
PubMed1980

Cimetidine in the prophylaxis of migraine.

The prophylactic effect of the histamine H2-blocker cimetidine, either alone or combined with an H1-blocker (chlorpheniramine), was investigated in 34 migraine patients in a double-blind crossover trial. Twelve patients withdrew during the course of the trial, one because of the side effects and the remainder because of failure to attend checkups or to keep adequate record of attacks. In the 22 patients who completed the trial, there were no significant responses to cimetidine or cimetidine + chlorpheniramine, during 3 months' therapy, as compared with 3 months' therapy with placebo, either on number, duration or severity of attacks. The study demonstrates that cimetidine is unlikely to be effective in migraine, and casts doubt on the role of histamine in the development of migraine attacks.

Adolescent↗
PubMed1980

Lipoteichoic acid-binding and biological properties of T protein of group A streptococcus.

T protein was extracted with trypsin from an avirulent, M protein-deficient, type 1 group A Streptococcus and purified by ammonium sulfate precipitation and anion-exchange chromatography. The latter procedure removed contaminating lipoteichoic acid (LTA) from the T protein, which consisted of a heterogeneous mixture of polypeptides resistant to digestion by trypsin and ranged in molecular size from 160,000 to 200,000 daltons. Threonine, aspartic acid, glutamic acid, lysine, and valine were the most predominant amino acids. The binding of LTA to an affinity column of T protein was reversible with increasing concentrations of ethanol but not with increasing ionic strength. T protein bound less palmitic acid and LTA than did fatty acid-free bovine albumin and did not stimulate human peripheral lymphocytes. Because the surface and cell wall distribution of the T proteins and LTA appear similar, the possibility exists that T proteins and LTA may interact in situ by weakly hydrophobic bonds. Such ligand-ligand interaction may be indirectly involved in the adherence of group A streptococci to host cell membranes that is known to be mediated by LTA.

Amino Acids↗
PubMed1980

Sodium valproate in the treatment of the alcohol withdrawal syndrome.

The value of sodium valproate in the management of patients during withdrawal from alcohol dependence has been assessed. Alcoholic inpatients were randomly allocated to two groups - one treated with sodium valproate and the other acting as a control. All patients received multivitamins and fluid and electrolyte replacement, and some received chlormethiazole or other tranquillisers. Treatment with sodium valproate (1200 mg daily) was continued for one week. The occurrence of seizures and other withdrawal symptoms (tremulousness, nausea, sweating, disorientation) were noted daily. Forty-nine episodes of withdrawal have been included in the trial - 22 in the sodium valproate group and 27 in the control group. Five patients, all in the control group, had seizures. Other withdrawal symptoms disappeared more quickly in the sodium valproate group even though fewer patients were receiving chlormethiazole.

Adult↗
PubMed1979

Human immune response to immunization with a structurally defined polypeptide fragment of streptococcal M protein.

We tested the ability of pepsin-extracted, highly purified M protein to induce type-specific immunity in experimental animals and humans. M protein was prepared from limited peptic digests of whole group A type 24 streptococci and was purified to chemical homogeneity as judged by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, quantitative amino acid analysis, and Edman degradation. For vaccination, the lyophilized M24 protein preparation (pep M24) was precipitated in aluminum hydroxide. When injected into laboratory animals, alum-precipitated pep M24 produced type-specific protective antibodies and was free of non-type-specific immunoreactivity. In man, skin tests with 1-microgram doses of pep M24 were negative in all 37 adults tested. 12 adult human volunteers received two-four subcutaneous injections of 100-200 micrograms of alum-precipitated pep M24 at intervals of at least 2 wk. The immune response to pep M24 was measured by a variety of assays designed to detect (a) type-specific humoral antibodies (opsonophagocytic, long chain, and mouse protection tests); (b) total humoral antibodies (complement fixation and enzyme-linked immunosorbent assay); (c) cellular immunity (skin tests); and (d) heart cross-reactive antibodies (immunofluorescence). Type-specific opsonic antibodies developed in 10 of the 12 vaccinees, and positive delayed-type skin tests developed in 11. Immune sera from two of the vaccinees were effective in mouse-protection tests against challenge with M24 but not M6 streptococci. None of the volunteers developed heart-reactive antibodies or antibodies to non-type-specific M protein antigens. Alum-precipitated pep M24 was well-tolerated in man, and no serious local or systemic reactions were observed. Thus, pep M24 induces type-specific, protective antibodies in doses that are well-tolerated in man.

Adult↗