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Biomedical subjects

R H Johnson

Publications and source records attributed to R H Johnson.

At least 181 records · Page 10Linked to original sources
PubMed1977

Metabolic changes during glucose tolerance tests in migraine attacks.

(1) Intravenous glucose tolerance tests have been carried out on 6 migraine sufferers on two occasions. The first study was carried out during a migraine attack and the second was performed in an attack-free period. The patients had fasted overnight and the investigations were carried out in the morning. Samples of venous blood were taken for measurement of concentrations of glucose, lactate, pyruvate, free fatty acids (FFA), glycerol, ketone-bodies, insulin and growth hormone. (2) an impaired tolerance to glucose was found during the migraine attacks compared with the control studies. Elevated ketone and FFA levels were found during the attacks and may have accounted for the glucose intolerance. The elevation of plasma FFA levels during the migraine attacks paralleled changes in blood glycerol concentrations suggesting increased lipolysis during the attacks. Growth hormone and cortisol were raised and insulin was depressed during attacks. (3) Our observations, in which the patients acted as their own controls, imply increased lipolysis during migraine attacks and are in contrast to previously reported studies. The patterns of metabolic and hormonal changes are consistent with a stress response during the attacks and the significance in relation to the causation of the attacks is discussed.

Adult↗
PubMed1977

The growth hormone response to insulin induced hypoglycaemia in alcoholics.

The growth hormone response to insulin induced hypoglycaemia was studied in 7 alcoholic in-patients who had been abstinent for 2-11 days and in 10 normal controls. Blood samples were taken at intervals after the injection of soluble insulin (0-1 U/kg body weight). The growth hormone response was impaired in 4 of the alcoholics and the depression was not related to differences in blood glucose or plasma free fatty acids. The cortisol response was also impaired in the alcoholics. We conclude that alcoholics observed after alcohol withdrawal may have a depression of hypothalamic/pituitary function.

Adult↗
PubMed1977

Serological responses in pigs vaccinated with inactivated porcine parvovirus.

The safety and immunogenicity of inactivated porcine parvovirus (PPV) vaccines were investigated. Both beta-propiolactone and formalin successfully inactivated virus without destroying immunogenicity, which was considerably enhanced by incorporation of a gel adjuvant in the vaccine. Using the formalised-gel vaccine, initial antibody responses were demonstrated in susceptible piglets and adult pigs at 7 days after vaccination. These antibody responses persist at significant levels for at least 6 months after vaccination. Antibody levels increased up to 16 fold when revaccination was carried out. Vaccination of gilts with low level (passive) immunity resulted in antibody responses comparable to those recorded in susceptible pigs. The vaccine was safe as determined by absence of residual virus in the vaccine, absence of viraemia and excretion in vaccinted stock, and absence of effect on litters of sows vaccinated at different gestational ages. Vaccine stored at 4 degrees C for 6 months was as immunogenic as fresh vaccine.

Animals↗
PubMed1977

The metabolic response to exercise in chronic alcoholics.

The metabolic response to steady exercise was studied in six chronic alcoholics and six normal control subjects. Higher concentrations of lactated and pyruvate were observed in the alcoholics during exercise and they also developed post-exercise ketosis. These changes were probably not due to reduced fitness of the alcoholics as the heart rates of both groups were similar. Alcoholics had lower levels of growth hormone during exercise compared with the controls suggesting that chronic alcohol consumption has a depressor effect on pathways regulating the release of growth hormone.

Adult↗
PubMed1977

Purification and characterization of group A streptococcal T-1 antigen.

A method is described for the recovery of purified T-antigen from crude trypsin extracts of an avirulent strain of M-1 protein deficient, T-type 1 group A Streptococcus. The purified T-antigen was resistant to enzymatic degradation with trypsin and pepsin, formed a single precipitin line with standard T-1 antiserum, failed to react with antisera for teichoic acid, group A carbohydrate, and cross-reactive protein antigens, stimulated only a single precipitin system when rabbits were immunized, contained glycine, aspartic acid, glutamic acid, lysine, and serine as the five most predominant amino acids, and consisted of subunit size isomers.

Agglutination Tests↗
PubMed1977

Idiopathic orthostatic hypotension from failure of noradrenaline release in a patient with vasomotor innervation.

A 26 year old man is described with life-long orthostatic hypotension unrelated to autonomic nerve degeneration and apparently due to failure of peripheral noradrenaline realese. Tests of parasympathetic and sympathetic cholinergic nerve function were normal, but sympathetic adrenergic activity was defective. Thus blood pressure regulation was abnoraml. There was no pressor response to tyramine, an indirect sympathomimetic drug, but a marked pressor response to the directly acting sympathomimetic drugs phenylephrine and noradrenaline. On standing there was a progressive fall rather than a rise in circulating noradrenaline concentrations, although adrenaline levels rose normally. The pupils showed diminished responses to ephedrine and cocaine, and a normal response to phenylephrine. Fluorescence microscopy of blood bessels showed that they were innervated with adrenergic nerves. His orthostatic hypotenstion responded well to oral phenylephrine (50 mg five times daily) but not to other forms of therapy. It is suggested that this patient's symptoms were due to failure of noradrenaline release even though sympathetic adrenergic nerves were present. We therfore wish to draw attention to a further cause of orthostatic hypotension, failure of peripheral noradrenaline release without autonomic neuropathy.

Adult↗
PubMed1977

Treatment of epilepsy with clonazepam and its effect on other anticonvulsants.

Clonazepam was added to the treatment of patients with poorly controlled epilepsy in a double-blind trial and an open trial. Considerable improvement occurred with patients with myoclonic jerks and tonic-clonic convulsions, and with photosensitive epilepsy. Patients with atypical petit mal and focal epilepsies also improved. Drowsiness was initially common but lasted only a short time. No evidence was found for an action of clonazepam on the metabolism of other drugs, but treatment with phenobarbitone lowered serum concentrations of clonazepam. We conclude that clonazepam is particularly valuable in epilepsy with associated myoclonsu and in photosensitive epilepsy.

Adolescent↗
PubMed1977

Hemophilus endocarditis: new cases, literature review and recommendations for management.

Rarely is endocarditis attributed to the species of Hemophilus. Most frequently implicated are H aphrophilus and H parainfluenzae, but H influenzae also is seen. We report six cases of endocarditis due to H aphrophilus or H parainfluenzae and review the literature. Emboli to skin, lungs, kidneys, spleen, brain, and other organs are common complications, and acute glomerulonephritis and meningitis often occur. Ampicillin is the mainstay of antimicrobial therapy for patients whose isolates are sensitive to it, but the duration of antimicrobial therapy necessary for eradication of the infection is not clear. Studies of antimicrobial synergism are warranted in instances of endocarditis caused by ampicilin- or penicillin-resistant strains of Hemophilus, or when patients are allergic to penicillin; in these instances, combination antimicrobial therapy must be given when bactericidal synergism can be demonstrated. Intensive management of complications caused by embolization is crucial to patient survival.

Adult↗
PubMed1976

Treatment of neurogenic orthostatic hypotension with a monoamine oxidase inhibitor and tyramine.

Six patients with neurogenic orthostatic hypotension were treated with a chemical preparation of tyramine and tranylcypromine ("Parnate"), a monoamine oxidase inhibitor (M.A.O.I.). Four had autonomic failure with no other neurological deficit (idiopathic orthostatic hypotension), and in two patients other neuronal systems were also involved (Shy-Drager syndrome). Previous therapy with fludrocortisone, ephedrine, elastic garments, postural training, and, in one patient, an anti-G suit was unsatisfactory. Tyramine given orally with tranylcypromine produced a moderate rise in blood-pressure which was sustained for 2-4 hours, enabling patients to walk about without symptoms of orthostatic hypotension. Measurement of circulating adrenaline and noradrenaline during therapy suggested that release of noradrenaline caused the pressor response. In three patients there has been a pronounced improvement for 8, 20 and 30 months. In a further patient, therapy has been successful in treating the orthostatic hypotension, although his mobility has been restricted by cerebellar ataxia. In one patient a confusional state developed during treatment and therapy was stopped. The only patient in whom the drugs did not produce a pressor response had orthostatic hypotension with failure of noradrenaline release. It is suggested that the pressor response to a M.A.O.I. and tyramine should be examined in patients with neurogenic orthostatic hypotension and that this treatment should be tried in those who respond.

Administration, Oral↗
PubMed1976

Metabolic changes during exercise testing of patients with ischaemic heart disease.

Nineteen patients who had recovered from a mild to moderately severe myocardial infraction 6--18 months previously were studied in order to investigate the relationship between the severity of myocardial insufficiency and metabolic changes developing during and after exercise. The patients were compared with six controls by means of a graded exercise test on a treadmill. Electrocardiographic records were made and blood pressure measured during and after the exercise and venous blood samples were taken for measurement of lactate, pyruvate, glycerol and free fatty acids. In five patients with moderate or advanced ischaemic electrocardiograph changes the blood lactate and pyruvate mean concentrations continued to rise up to a further 50% after they stopped exercising. The other patients, including some who developed symptoms suggestive of myocardial ischaemia, and all the controls, failed to show these marked increases in blood concentrations after the exercise. We conclude that the development of myocardial insufficiency during exercise is associated with marked increases in lactate and pyruvate concentrations in the peripheral blood particularly after the exercise has ceased.

Adult↗
PubMed1976

Therapeutic and pharmacokinetic effects of increasing phenytoin in chronic epileptics on multiple drug therapy.

Twenty chronic epileptics receiving phenytoin and either phenobarbitone or primidone have been studied. All patients had frequent seizures and had serum concentrations of phenytoin below 410 mumol/1. Phenytoin dosage was increased to study the effect on the frequency of seizures and the serum concentrations of phenytoin and phenobarbitone. There was no effect on minor seizures but in ten out of sixteen patients major seizures were abolished or reduced. Serum concentrations of phenobarbitone rose as the phenytoin dose was increased. This may cause deviations from the expected relationship between dose and serum concentrations of phenytoin; this would explain deficiencies which were found in a nomogram for predicting the therapeutic dose of phenytoin.

Adult↗
PubMed1976

Observations on the pathogenesis of porcine parvovirus infection.

Differences in the pathogenesis of porcine parvovirus (PPV) were shown when pregnant gilts were infected by the oral and intramuscular (i.m.) routes. By the oral route, PPV took 23-32 days to cross the placenta following infection of the dam, as compared to 15 days by the i.m. route, Successful transplacental infection occurred following oral infection of dams only in the second third of gestation, whilst i.m. infection resulted in infection of foetuses in both first and second thirds of gestation. Foetal infection resulted in death and mummification only where infection of foetuses occurred before onset of immune competence--estimated at 70 days gestation. Infected foetuses either died before onset of immune competence, or survived to mount an immune response with subsequent death or survival to farrowing. It is suggested in discussion that reproductive failure due to PPV, characterised by mummification or occasional stillbirth, is associated in nature with oral infection, and occurs only when dams are infected in the first part of the midthird of gestation.

Animals↗
PubMed1976

Visceral fungal infections due to Petriellidium boydii (allescheria boydii). In vitro drug sensitivity studies.

Four patients with visceral infections due to the fungus Petriellidium boydii, who were recently hospitalized in our institutions, are described. Three of the patients were compromised hosts; in the fourth patient, infection occurred after trauma. All had received prior steroid and antibiotic therapy. Studies of patients with mycetoma or secondary infection of a pulmonary cavity due to this organism and of patients with visceral infections are reviewed. Because of histologic similarities to Aspergillus species, infections due to P. boydii may have been misdiagnosed in the past if the infecting fungus was not isolated in culture. The fungus has been shown to be resistant in vitro to currently available antifungal agents. Resistance to amphotericin and 5-fluorocytosine is demonstrated in our studies. There are few reports of successful chemotherapy of any manifestation of this infection, and no such reports of visceral disease. We demonstrate in vitro sensitivity of isolates in our cases and in others to micronazole, a new antimicrobial agent; this drug may be indicated for treatment of disease due to P. boydii.

Adult↗
PubMed1976

The effect of hypocapnia and change of blood pressure on cerebral blood flow in men with cervical spinal cord transection.

Cerebral blood flow (CBF) was measured by a 133Xe inhalation technique in 8 patients with chronic high spinal cord injuries. Six patients had a physiologically complete cervical cord transection and 1 subject had an incomplete C4-5 lesion but with evidence of interruption of sympathetic pathways. CBF and arterial blood pressure (BP) were measured in the supine position and then in the sitting, or feet up, position to produce a change of BP. In 4 patients CBF was measured during a suction manoeuvre applied to the lower half of the body to produce a fall of BP. There was no significant change of CBF in the patients during hypo- and hypertension. The response of CBF to hyperventilation for 5 min was measured in the supine position and did not differ significantly from that of 13 normal "control" subjects and 1 patient with a lesion at T2-3. It is concluded that the responses of the cerebral circulation to change of blood pressure and to hypocapnia are normal in patients with high spinal cord transection. The mechanisms involved in these responses are therefore independent of control via cervical sympathetic pathways.

Adult↗