Search PubMed⌕ Search

Biomedical subjects

A F Hallett

Publications and source records attributed to A F Hallett.

At least 19 recordsLinked to original sources
PubMed1987

Epstein-Barr virus reactivation in renal transplant recipients.

Renal transplant recipients at Tygerberg Hospital were investigated to determine the importance of Epstein-Barr virus (EBV) as a pathogen in these patients. All 106 patients investigated were shown to have EBV antibodies before transplantation and most had serological evidence of reactivation of the infection after transplantation. A mild clinical illness was present in a few patients concomitant with EBV reactivation, which may suggest that this virus has a role in the morbidity of some renal transplant recipients. Lymphoblastoid cell lines were established from 11 renal transplant recipients; 5 of these cell lines were shown to be virus producers and 1 is thought to have unique properties.

Antibodies, Viral↗
PubMed1985

A nosocomial outbreak of Crimean-Congo haemorrhagic fever at Tygerberg Hospital. Part V. Virological and serological observations.

A nosocomial outbreak of Crimean-Congo haemorrhagic fever occurred in Tygerberg Hospital near Cape Town in September 1984 when 7 medical personnel became ill after admission of an index patient. The disease was fatal in the index and 1 secondary case, and was confirmed in the index and 6 secondary cases by isolation of the virus. An antibody response was demonstrated in the remaining patient, thought to be a tertiary case, but the fact that the patient received immune plasma therapy raises doubts about the validity of the diagnosis. The index case had contact with ticks and horses but his infection could not be related to a specific incident.

Antibodies, Viral↗
PubMed1982

The in vitro activity of amoxycillin with clavulanic acid against clinically significant bacteria. A multicentre study.

A multicentre study to evaluate the activity of amoxycillin when combined with clavulanic acid against clinical bacterial isolates was performed in South Africa. Minimum inhibitory concentrations for amoxycillin alone and in combination with clavulanic acid were determined by agar dilution. The majority of amoxycillin-resistant Klebsiella and Escherichia coli strains became sensitive to amoxycillin in the presence of low concentrations of clavulanic acid. Beta-lactamase-producing strains of Staphylococcus aureus showed increased susceptibility to amoxycillin in the presence of clavulanic acid. Minimum bactericidal concentrations indicated that amoxycillin retains bactericidal activity in the presence of clavulanic acid. Enterobacter and Serratia species and Pseudomonas aeruginosa remained amoxycillin-resistant in the presence of clavulanic acid.

Amoxicillin↗
PubMed1982

Pharmacological modulation of neutrophil phagocytic function in a patient with recurrent sepsis, pyoderma gangrenosum and impaired phagocytosis.

A 50-year-old man with recurrent life-threatening sepsis and a cutaneous condition resembling pyoderma gangrenosum, was found to have a defect of neutrophil phagocytic function. Phagocytosis could be enhanced by corticosteroids, both in vitro in a dose-dependent manner, and in vivo, when it was accompanied by rapid clinical improvement. Studies with steroid hormones and immuno-stimulatory drugs are described.

Adrenal Cortex Hormones↗
PubMed1980

Complement activation in Staphylococcus aureus bacteraemia.

Serum levels of complement components C3, C4 and factor B were measured in twenty-five patients with Staphylococcus aureus bacteraemia. The levels of C3 were depressed in nine patients, five of whom also had low C4 levels, indicating activation of complement via the classical pathway. Two patients with low C3 levels also had low factor B levels, one of these being in association with a low C4 level, which indicates activation of both the classical and alternative pathways, the latter being via the C3b feedback cycle. The protein A content of the S. aureus cultures, as shown by the indirect haemagglutination titre, was high in nine patients with C3 hypocomplementaemia. There was some correlation between the presence of a high protein A content of the S. aureus culture and a low serum C3 level in the patient. Some clinical evidence of immune complex disease was found in three patients. Complement activation in S. aureus bacteraemia is most likely due to complex formation resulting from the interaction between the Fc portion of IgG and staphylococcal protein A. These complexes may also result in clinical symptoms of immune complex disease.

Adult↗
PubMed1979

Group B streptococci in blacks.

Vaginal swabs were taken from 60 Black women attending a family planning clinic and from 60 attending a special clinic for sexually transmitted diseases. Using selective media, the isolation rate for group B streptococci was 26,7% in the former group and 40,0% in the latter. The isolation rates of other streptococcal serogroups are also given. All group B streptococci isolated were uniformly sensitive to penicillin but resistant to gentamicin. Clinical details of 7 patients with group B streptococcal septicaemia are also given.

Adult↗
PubMed1978

Meningitis caused by Streptococcus dysgalactiae in a preterm infant.

This report describes a case of meningitis caused by a Lancefield group C streptococcus (Streptococcus dysgalactiae) in a 9-week-old infant. Bacteria of this group rarely cause serious infections in man. The organism was identified as a member of Lancefield group C by the acid extraction method and as S. dysgalactiae by biochemical tests. The patient's condition responded well to penicillin and tobramycin therapy, with no obvious neurologic sequelae.

Anti-Bacterial Agents↗
PubMed1978

Alterations in immune responsiveness in acute measles and chronic post-measles chest disease.

Immune responses in 24 children with acute measles (AM) were compared with those in 20 children who had chronic pulmonary complications (CPMC) following measles. The immuno-suppressive effects of acute measles were extensive: total white cells were reduced and this reduction was accounted for entirely by lymphopenia which was equally expressed among the major lymphocyte sub-populations studied; the function of 'T' cells, assessed by radio-isotope incorporation into phytohaemagglutin (PHA) transformed lymphocytes and delayed skin hypersensitivity (DHR) to dinitrochlorobenzene (DNCB), was depressed. Serum IgA was reduced in AM patients. In contrast there was a relative sparing of the measured indices of immunity in patients with chronic post-measles chest disease, with the major defect being an impaired DHR to DNCB. There were minor alterations of complement components in both groups of patients.

Acute Disease↗
PubMed1977

Respiratory infection in an intensive care unit.

A postmortem bacteriological study of Black children in a respiratory intensive care unit showed that Pseudomonas aeruginosa was the most common opportunistic pathogen and that it usually complicated a viral infection. In a parallel study of non-debilitated patients in general hospital wards Klebsiella aerogenes and Escherichia coli were the most frequently isolated organisms. Counter-immuno-electrophoresis was used for the identification of Pseudomonas-precipitating antibody in serum and tracheal secretions, and also of Pseudomonas antigen in the latter.

Antigens, Bacterial↗
PubMed1977

Streptococcus pneumoniae resistant to penicillin and chloramphenicol.

Three cases of meningitis and two of septicaemia were caused by pneumococci resistant to the penicillins/cephalosporins and chloramphenicol. No beta-lactamase was demonstrated in any of the organisms. All three patients with meningitis died, but the patients with septicaemia recovered after being given appropriate antibiotic therapy.

Anti-Bacterial Agents↗
PubMed1977

Immunoparesis and outcome in measles.

In five children with measles who subsequently died and in one with measles in whom chronic bronchopneumonia developed (group A), immunosuppression was more pronounced during the acute rash (i.e., 3-20 days before death) than in six children with measles who recovered (group B). The absolute total lymphocyte-count (T and B cells) was significantly lower in group A. Mean serum-C3 was also lower in group A than in group B. There were no significant differences between the two groups for other complement factors or for serum-immunoglobulins. The mean phytohaemagglutinin stimulation index (S.I.) for lymphocytes from patients in group A resembled that in group B, although the S.I. in both groups was significantly lower than that in healthy controls. S.I.S were lowest in two patients who died. Counts of total white cells, neutrophils, null cells, and those with both B and T cell markers were not significantly different in groups A and B. The total lymphocyte-count (mean 2117 +/- S.E.M. 375 cells/mm3) in a further nineteen patients with measles who had died, studied retrospectively, was significantly lower than that (4487 +/- 540 cells/mm3) in twenty-seven patients with measles who recovered.

Bronchopneumonia↗
PubMed1977

Post-streptococcal glomerulonephritis in African children.

Streptococcal infection remains almost the sole cause of the clinical syndrome of acute glomerulonephritis in African children. Evidence for this is in elevated levels of antistreptolysin "O" (ASO) titre in 93% of 28 patients and growth of Group Abeta haemolytic streptococci from the skin and throat in 32%. Spread of infection from the skin, where lesions were present in all patients, to the throat would account for positive cultures at both sites and the frequent and vigorous antistreptolysin "O" responses. Clinical recovery occurred in most within seven days and in all within 60 days of admission. IgG and IgA, but not IgM, were increased in patients; C4 was normal in the majority and low in seven out of 24 (29%), C3 was diminished in 26 out of 28 (93%) and the mean level of C3 PA was lower than in controls. Total haemolytic complement paralleled C3 values; C3 breakdown products were not detected in any patient. Renal biopsies in seven out of 28 patients showed typical histological changes of diffuse exudative proliferative glomerulonephritis on light microscopy and fibrinogen and C3 on immunofluorescent staining. These findings suggest that events leading to glomerular damage in acute post-streptococcal nephritis in African children involve activation of both classical and alternative pathways of complement proteins and also confirm the well recognized and predictable nature of the disease, irrespective of geographical distribution.

Acute Disease↗
PubMed1977

Isolation of Campylobacter fetus from recent cases of human vibriosis.

Campylobacter fetus was isolated from five recent cases of human vibriosis, of which two were adults and three were children. One adult presented with pericarditis and the other with recurrent pyrexia. Campylobacter fetus subsp. intestinalis which resembled cattle strains serologically, was isolated under CO2 or anaerobic conditions from blood cultures of these patients. Two of the three children had kwashiorkor and the third was only 8 days old. Isolates identified as Campylobacter fetus subsp. jejuni were cultured from blood of these patients, two of whom had diarrhoea. Three patients succumbed, despite adequate antibiotic therapy. The epidemiology of the disease is discussed and it is suggested that infection may have been from the patients' own flora.

Adult↗
PubMed1977

Evaluation of live attenuated plague vaccines in Praomys (Mastomys) natalensis.

A live attenuated Yersinia pestis vaccine designated EV76-51f, which had previously been shown to be pathogenic in vervet monkeys but not in guinea pigs, was tested in the multimammate mouse Praomys (Mastomys) natalensis. Doses of 10(6) viable organisms inoculated subcutaneously as either a lyophilized suspension or an agar-grown culture resulted in vaccination fatalities in Praomys but not in white mice. Hemagglutinating antibodies to the fraction 1 antigen were not stimulated by doses lower than 10(4) viable organisms. Agar-grown cultures of the vaccine gave better protection against a virulent Y. pestis challenge than did a lyophilized suspension. All Praomys vaccinated with a dose of 10(6) agar-grown EV76-51f protected against a virulent challenge, whereas even doses up to 10(8) lyophilized bacilli failed to give complete protection. The pathogenicity of a live attenuated plague vaccine derived from the Y. pestis EV76 vaccine strain can be detected in Praomys (Mastomys) natalensis, a rodent species highly susceptible to plague. This animal species may therefore be valuable for the testing of live attenuated plague vaccines before they are tested in costly nonhuman primates.

Animals↗