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Biomedical subjects

J Holt

Publications and source records attributed to J Holt.

At least 109 records · Page 6Linked to original sources
PubMed1983

Changes in left ventricular ejection fraction after intracoronary thrombolytic therapy. Results of the Registry of the European Society of Cardiology.

Changes of left ventricular ejection fraction (delta EF) determined by monoplane contrast angiography before intracoronary streptokinase infusion and in the chronic stage of infarction before hospital discharge were assessed in 125 patients. Preintervention EF was .49 +/- .136 and chronic EF was .025 +/- .118 higher (p = .02) in the total group. Some subgroups had an improved EF: patients with collaterals (delta EF = .046 +/- .106, p less than .01, n = 42), patients with incomplete obstruction before intervention (delta EF = + .076 +/- .141, p = .03, n = 19) and patients in whom complete obstruction was permanently recanalized (delta EF = .024 +/- .113, p = .04, n = 89). A continuous model relating delta EF to both duration of infarct symptoms before hospital admission and to preintervention EF showed a decline in EF improvement over time in the subgroup that was admitted within less than 6 hours after the onset of chest pain and successfully recanalized (n = 72).

Cardiac Output↗
PubMed1982

Epidemiologic and clinical features of patients infected with Shigella who attended a diarrheal disease hospital in Bangladesh.

The epidemiologic and clinical characteristics of 412 patients infected with Shigella from a systematic sample of approximately 100,000 patients attending Dacca Hospital, International Centre for Diarrhoeal Disease Research, Bangladesh, between December 1, 1979, and November 30, 1980, were reviewed. Shigella was isolated from 11.6% of the 3,550 patients in the sample and was the second most common isolate in patients over two years old. Two clinical presentations of shigellosis were found: (I) watery diarrhea occurring in younger children and associated with a shorter duration of illness and with more vomiting and dehydration and (2) dysentery with stool blood and abdominal pain. These different presentations may reflect two mechanisms in the pathogenesis of shigellosis or different stages of the disease. The most useful signs and symptoms for the diagnosis of shigellosis were stool with blood and abdominal pain in all patients and the absence of watery diarrhea and vomiting in patients over one year old. Simple visual inspection of stool for blood correctly identified 44% of all patients infected with Shigella.

Adolescent↗
PubMed1982

Selective depression of motion sensitivity during saccades.

1. Horizontal gratings flashed for 20 ms were used to compare visual contrast sensitivity during horizontal saccades with sensitivity during normal vision, at three luminance levels, 4 X 10(2), 4 X 10(-2), and 4 X 10(-4) cd/m2. 2. Greatest sensitivity loss during saccades was found at low spatial frequencies. There is little or no loss at high spatial frequencies. 3. As luminance level is decreased there is a decrease in the spatial frequency below which saccadic sensitivity loss occurs. This shift in spatial frequency with luminance level, considered in conjunction with measurements of stationary and drifting gratings, indicates the functional involvement of movement sensitive mechanisms in saccadic sensitivity loss. 4. At the two lower luminance levels (4 X 10(-2) and 4 X 10(-4) cd/m2) sensitivity during saccades is greater than normal at high spatial frequencies. This enhancement of sensitivity was confirmed by forced choice measurements. 5. It was also shown that sensitivity to abrupt changes in the trajectory of moving gratings is lowered during saccades. 6. It is concluded that mechanisms sensitive to movement and transients are damped during saccades, so preventing perception of image motion during saccades and thereby preserving visual stability.

Eye Movements↗
PubMed1982

Hemodynamic consequences of combined beta-adrenergic and slow calcium channel blockade in man.

The administration of verapamil to patients receiving beta-adrenergic blocking drugs is reported to produce adverse circulatory reactions, but a systematic investigation of this potential drug interaction has not been performed in man. We administered 40-, 80- and 120-mg doses of verapamil orally to 15 patients with angina pectoris who were receiving high doses of propranolol or metoprolol. Verapamil produced dose-dependent decreases in cardiac performance: with 120 mg, cardiac index decreased by 0.38 l/min/m2, stroke volume index decreased by 2.8 ml/beat/m2 and heart rate decreased by 6 beats/min, associated with increases in pulmonary capillary wedge (2.2 mm Hg) and mean right atrial pressures (1.7 mm Hg) (all p less than 0.01); two patients had marked, but asymptomatic, hypotensive reactions. In contrast, repeat administration of 120-mg doses of verapamil 24--30 hours after withdrawal of beta blockade produced no significant cardiodepressant effects despite significantly higher plasma levels of verapamil than during propranolol therapy (383.1 vs 205.1 ng/ml, p less than 0.01). In conclusion, verapamil produces significant negative inotropic and chronotropic effects in patients treated with beta-adrenergic antagonists; combination therapy should therefore be used with caution in patients with angina pectoris.

Adult↗
PubMed1980

Changing epidemiology of malignant melanoma in Queensland.

Information provided by Queensland pathology laboratories shows that the annual incidence of cutaneous malignant melanoma in Queensland has doubled from 16 per 100 000 population in 1966, to 32.7 per 100 000 in 1977. The incidence in males, and the males to females ratio have increased. The major sites of the tumour remain the same, except possibly for a reduction in the number of leg tumours in females in tropical Queensland. More tumours with an in-situ component of Hutchinson's melanotic freckle type are being diagnosed. The tumours diagnosed in 1977, compared with those in the Queensland Melanoma Project files from 1963 to 1969, are more superficial (Level 1 or Level 2), with nonelevated profile and smaller diameter. The findings suggest that the disease is being diagnosed and treated earlier.

Adolescent↗
PubMed1980

On transforming biological data to Gaussian form.

Much of the statistical analysis of biological data depends on the assumption that the data are Gaussian (or normal). Some well-known procedures which use this assumption are (i) t-tests (ii) analysis of variance (iii) regression estimation and their attendant tests. If the data are not Gaussian, one can use nonparametric statistical techniques, if they exist, but they often require larger amounts of data to obtain equally precise results (see for example Lumsden and Mullen (7) for a discussion of this with regard to reference value estimation). If the data are not Gaussian a fruitful approach to their analyses lies in trying to find a transformation which will render tham Gaussian. The data thus transformed to a Gaussian form, can be analyzed validly using standard statistical techniques. The process of finding a good transformation of the data has often been an arbitrary and ad hoc one. The purpose of this article is to look at a particular technique for attempting to render nonGaussian data Gaussian, and to illustrate its applicability and breadth of use.

Animals↗
PubMed1979

Prospective study of chlamydial infection in neonates.

Chlamydia trachomatis was recovered from the cervices of 4% (36/900) of pregnant women tested. 20 infants born through chlamydia-infected cervices were followed up for a year, as were 18 infants born to chlamydia-negative mothers. A statistically significant excess of conjunctivitis and pneumonia was found in infants exposed to chlamydia. The attack-rate for inclusion conjunctivitis was 35% (7/20) and for chlamydial pneumonia it was 20% (4/20). Chlamydiae were recovered from 10 of the 20 (50%) exposed infants, and seroconversion was demonstrated in 14 (70%). None of the 18 unexposed infants showed evidence of chlamydial infection. Thus in our clinic 2.8% of all newborns acquired chlamydial infection, with incidence-rates of 14 cases of conjunctivitis and 8 cases of pneumonia per 1000 live births. Neonatal chlamydial infection is thus a major public-health problem warranting a preventive programme based on the fuller provision of diagnostic services and the treatment of infected pregnant women.

Cervix Uteri↗
PubMed1979

Infection with Chlamydia trachomatis: involvement of multiple anatomic sites in neonates.

In a study of infection due to Chlamydia trachomatis in infants, chlamydiae were recovered not only from the conjunctiva and respiratory tract but also from the vagina and rectum. The timing of recovery suggested that the vagina and conjunctivae are exposed to chlamydiae at birth and that pneumonia and gastrointestinal infection occur later. Sampling of the rectum may be a useful procedure for the diagnosis of chlamydial disease in infants.

Chlamydia Infections↗
PubMed1979

Mortality and complications of large-bowel resection for carcinoma.

The mortality and complications of large-bowel resection for carcinoma performed at the Princess Alexandra Hospital since the Colorectal Project commenced in 1971 are reviewed and compared with the results in other published series. There were 443 patients in this prospective study, and 375 underwent resection of their tumour. The overall operative mortality was 6.4% - for colonic lesions it was 8.0% and for rectal 3.4%. The mortality for elective curative resections was 2.6%, and for emergency resections it was 10.8%. The anastomotic leak rate was 6.8%, but was higher (16.6%) when the anastomosis was done at the time of emergency resection. No patient whose anastomosis leaked but who had had a previous defunctioning proximal colostomy died. There was a wound infection rate of 15.1%.

Adult↗
PubMed1978

The effects of drought on human nutrition in an Ethiopian province.

In mid 1974 the authors conducted a survey of Harerghe Province, Ethiopia in order to verify reports of serious effects of drought six months earlier. Information was obtained on anthropometric nutritional status, mortality, livestock, and market prices from a random sample of 62 villages in four ecological zones - the highlands, the northern and southern rangelands and an intermediate zone of mixed economy. The rangelands and intermediate areas had experienced heavy human and livestock losses during the drought but this had not occurred in the highlands. Although a high prevalence of malnutrition was found in every area studied, the geographical and height distribution of malnutrition within population groups suggested that this could only be clearly attributed to the effects of unusual food shortage in one part of the southern rangelands.

Adolescent↗