Biomedical subjects

J Hitchcock

Publications and source records attributed to J Hitchcock.

15 recordsLinked to original sources

PubMed1994

Epidemiology of invasive Haemophilus influenzae infections in Cape Town, South Africa.

The full spectrum of invasive Haemophilus influenzae disease has not been documented previously in Africa. This 1-year prospective study was designed to determine the epidemiology of invasive Haemophilus influenzae disease in Cape Town children. During this period, 142 children with invasive disease were hospitalized; 85 (59.9%) presented with meningitis, 35 (24.6%) with pneumonia and 22 (15.5%) with other diseases. No cases of epiglottitis were seen. Sixty per cent of cases were male and 40% female. The median age of the children was 9 months, with a range of 1-144 months, and 65.5% were aged < 12 months. Neurological dysfunction was noted in 40% and 18% of children with meningitis on admission and discharge, respectively. The overall case fatality rate (95% confidence intervals) was 9.2% (4.9-15.7), and for meningitis, pneumonia and septicaemia it was 4.7% (1.2-16.4), 14.3% (4.6-31.8) and 40% (8-78.1), respectively. Serotype b accounted for 86.5% of all cases, 97.3% of cases of meningitis, 71.4% of cases of pneumonia, 50% of cases of septicaemia, all cases of arthritis and cellulitis and none of mastoiditis. The incidence rates (95% confidence intervals) for all invasive type b infections were 169 (122-198) and 47 (39-57) per 100,000 population for children < 1 and < 5 years, respectively. For meningitis the rates were 112 (84-148) and 34 (25-40) per 100,000, respectively. Rates for mixed race and white children were similar, but those for black children were more than double those rates.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Distribution↗

PubMed1994

Serotypes and antimicrobial susceptibility of Haemophilus influenzae.

During a one year prospective study of Haemophilus influenzae infections in patients treated in hospitals in the metropolitan area of Cape Town. H. influenzae type b accounted for 81.7% of 126 invasive isolates, whereas 86.1% of the 280 non-invasive isolates were non-typeable. Ampicillin resistance was detected among 10.8% of strains of which all but one produced beta-lactamase. All strains were susceptible to cefotaxime as were more than 95% to chloramphenicol, rifampicin, tetracycline but 20.4% were resistant to co-trimoxazole and 87.2% to erythromycin.

Adult↗

PubMed1994

Carriage of Haemophilus influenzae in Cape Town children.

Little is known about the epidemiology of Haemophilus influenzae infections in South Africa. This study was designed to determine the prevalence, serotype distribution, antimicrobial susceptibility pattern and effect of age and hospitalisation on the carriage of H. influenzae in 322 Cape Town children. The overall and type b specific carriage rates in normal children (N = 107) were 45.8% and 4.7% respectively. The yield following nasopharyngeal culture was twice that following throat culture (P < 0.001). Children hospitalised with tuberculosis (N = 62) had significantly greater carriage rates, 66.1% and 37.1% respectively (P = 0.02). Institutionalised mentally handicapped children (N = 77) and children with tuberculosis attending an outpatient clinic (N = 76) had lower carriage rates (P < 0.02). Antimicrobial resistance was a major problem only in children hospitalised with tuberculosis (rifampicin 100%, penicillin 43.9%, erythromycin 85.4%, co-trimoxazole 82.9%). This universal resistance to rifampicin has not been reported previously. There was no difference in the mean age of children with positive or negative cultures, with the exception of those hospitalised with tuberculosis. In this group children infected with type b were much younger (mean 19.7 months) than those with other and non-typeable infections (32.1 months) and the non-infected (50.1 months) (P = 0.04). Duration of hospitalisation or outpatient therapy in the patients with tuberculosis did not influence carriage rates.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗

PubMed1986

Lesions of the amygdala, but not of the cerebellum or red nucleus, block conditioned fear as measured with the potentiated startle paradigm.

Rats were given 10 light-shock pairings on 2 successive days. At 24-48 hr following training, groups of rats received bilateral transection of the cerebellar peduncles, bilateral lesions of the red nucleus (which receives most of the cerebellar efferents), or bilateral lesions of the central nucleus of the amygdala. Control rats were sham operated. At 3-4 days after surgery, the rats were tested for potentiated startle (increased acoustic startle in the presence of the light previously paired with shock). Potentiated startle was blocked by lesions of the central nucleus of the amygdala. Transection of the cerebellar peduncles or lesions of the red nucleus did not block potentiated startle. A second experiment in which a visual prepulse test was used indicated that the blockade of potentiated startle observed in the animals with amygdala lesions could not be attributed to optic tract damage. A third experiment demonstrated that the absence of potentiation in the animals with amygdala lesions was not simply due to a lowered startle level ceiling, because these animals could show increased startle with increased stimulus intensity and with administration of strychnine, a drug that increases startle. Taken together, the results are consistent with the hypothesis that the amygdala is involved in fear conditioning, because potentiated startle is a measure of conditioned fear.

Amygdala↗

PubMed1986