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Biomedical subjects

D Knight

Publications and source records attributed to D Knight.

At least 55 records · Page 3Linked to original sources
PubMed1995

Attributions for illness and treatment interventions by community nurses.

The present study evaluated community nurses' attributions for a case patient's heart attack and their recommendations for treatment. Eighty-nine district nurses and health visitors completed a set of rating scales following a case vignette describing a patient who had suffered a heart attack and prior to which had either adopted a healthy lifestyle (n = 47) or had maintained unhealthy behaviours (n = 42). The results suggest that subjects in the unhealthy-behaviour condition rated the case patient as less likely to follow advice, more responsible for his/her condition and rated the heart attack as more preventable. In addition, the results suggest that subjects were more likely to offer recommendations for behavioural change to the unhealthy case patient and that these recommendations were significantly related to internal attributions of patient responsibility. The results are discussed in terms of theories of health professionals' beliefs and behaviours.

Adult↗
PubMed1994

The effects of two acylcoenzyme A: cholesterol acyltransferase (ACAT) inhibitors, cyclandelate and a non-hydrolysable ether analogue, benzyl3,3,5-trimethylcyclohexanol on low density lipoprotein metabolism in macrophages and hepatocytes.

Cyclandelate (3,3,5-trimethylcyclohexanylmandelate) caused a dose-dependent decrease in the metabolism of radioiodinated low density lipoprotein [125I-LDL] by J774 mouse macrophages. This was probably an indirect effect due to the inhibition of cholesterol esterification by the cells rather than a direct one on the interaction of LDL with its receptor, since no inhibition was seen in cells which had been cholesterol-depleted by prior incubation with lipoprotein-depleted serum for 48 hr. Cyclandelate also inhibited immediately de novo synthesis of cholesterol from [1-14C]acetate in J774 cells, suggesting a direct action of the drug on an enzyme of the cholesterol biosynthetic pathway. The drug was an efficient inhibitor of hamster and rat intestinal acylcoenzyme A: cholesterol acyltransferase (ACAT) activity in vitro with an IC50 of 20 microM. Addition of cyclandelate to the diet of meal-fed rats caused a marked inhibition of the rate of appearance of dietary [4-14C]cholesterol in the plasma. A nonhydrolysable ether analogue of cyclandelate, benzyl3,3,5-trimethylcyclohexanol, was prepared to compare hepatic and extrahepatic actions of the two molecules. The analogue inhibited cholesterol esterification in J774 cells, transformed human macrophages U937 and human umbilical vein endothelial cells with an IC50 of 20 microM and had effects similar to those of cyclandelate on 125I-LDL metabolism in J774 cells. Differences between the analogue and cyclandelate were seen in hepatocytes and hepatic microsomal fractions, where preincubation with the analogue inhibited cholesterol esterification in both systems while cyclandelate had no inhibitory action in either. Consequently, preincubation of rat hepatocytes with benzyl3,3,5-trimethylcyclohexanol for 17 hr caused a marked decrease in the binding of 125I-LDL to the cells, whereas binding to cells preincubated with cyclandelate was the same as to control cells.

Acyl Coenzyme A↗
PubMed1994

Respiratory distress syndrome in New Zealand: evidence from the OSIRIS trial of exogenous surfactant (Exosurf).

AIMS: To assess the impact, mortality, morbidity and economic costs, of respiratory distress syndrome severe enough to warrant ventilation in one year in New Zealand. METHODS: Review of data from all five New Zealand regional neonatal intensive care units' participation in the international OSIRIS trial of exogenous surfactant (Exosurf) treatment for respiratory distress syndrome (involving 6700 infants in 21 countries), and extrapolation of these data to a full year. RESULTS: There were 265 New Zealand infants entered in the OSIRIS trial; the mean birthweight was 1335 g and mean gestation 29 weeks; 61% of infants were less than 30 weeks gestation. Forty-seven infants (17.7%) died prior to discharge from hospital, 40 deaths being attributed to prematurity or respiratory distress syndrome. One hundred and two infants (38.5% of the cohort; 45% of surviving infants) were oxygen dependent and 36 infants (13.6%) were dead at 28 days of age. Thirty-four infants (12.8% of the cohort; 15% of surviving infants) were oxygen dependent and 40 infants (15%) were dead at the expected date of delivery. Infants were intubated for a mean 12.5 days, with surviving infants of less than 27 weeks gestation intubated for a disproportionately long period of time. Seventy-two infants (29% of the 246 infants examined) had an abnormality detected by cranial ultrasound scan at 1 or 6 weeks of age and in 23 (9%) this was a major abnormality. Of surviving infants 16 (7.5% of 213 examined) had a major abnormality on cranial ultrasound scan. Amongst infants at high risk for respiratory distress syndrome (gestation less than 30 weeks) 53% received antenatal steroids, compared with 22% in the OSIRIS trial overall. In a full year the cost of caring for infants with respiratory distress syndrome sufficiently severe enough to warrant ventilation is estimated to be NZ$12.5 million. The average cost of caring for a surviving infant was roughly NZ$52,500 and a nonsurviving infant was NZ$24,500. CONCLUSIONS: In a full year (total births 60,000) approximately 350 New Zealand infants may require ventilation for respiratory distress syndrome. Increasing the percentage of infants who receive antenatal steroids is likely to be extremely cost effective. In the era of antenatal steroids and exogenous surfactant, 85% of infants with respiratory distress syndrome requiring ventilation survive to discharge home and over 90% of survivors are likely to be healthy normal adults.

Birth Weight↗
PubMed1994

Popliteal pseudoaneurysm as a complication of an adjacent osteochondroma.

A 19-year-old man presented to our institution with a 4-month history of a pulsatile mass in the left popliteal fossa. Evaluation including plain x-ray films, MRI, and arteriography revealed a pseudoaneurysm associated with an underlying exostosis of the distal femur. The pseudoaneurysm was repaired with a saphenous vein patch and the exostosis was excised. This case is reported in conjunction with an extensive review of the literature, which yielded only 25 similar cases reported in the English language since 1953. The majority of cases involved young men (20/26), whose ages ranged from 9 to 45 years (mean 20 years). Fifteen of the 26 cases involved isolated exostoses, and in less than half (12/26), antecedent trauma was identified as a cause of the pseudoaneurysm. The origin of exostoses and their relationship to popliteal pseudoaneurysms are discussed. Repair of the pseudoaneurysm and excision of the involved exostosis are recommended.

Adult↗
PubMed1994

Oxygen and 99mTc-MAA shunt estimations in patients with pulmonary arteriovenous malformations: effects of changes in posture and lung volume.

BACKGROUND: Patients with arteriovenous malformations are routinely monitored with arterial oxygen saturation (SaO2) estimations (breathing air) from which an oxygen shunt fraction can be calculated. This simple estimation has been compared with an anatomically defined estimate of the right to left shunt using a radioisotopic method. The fall in SaO2 which occurs in patients with pulmonary arteriovenous malformations in the erect posture and at high lung volumes was used to test the ability of SaO2 alone to follow changes in right to left shunt. METHODS: Radiolabelled albumin macroaggregates (99mTc-MAA) or microspheres (MS) were injected intravenously and kidneys and lungs were imaged. The shunt fraction (QS/QTTc) in the supine position at functional residual capacity (baseline) was obtained by quantifying right kidney radioactivity. On standing or while breath holding at total lung capacity, shunt fraction was calculated from baseline QS/QTTc and from lung counts and the injected dose. Arterial oxygen saturation (SaO2) was recorded by a pulse oximeter for calculation of the oxygen shunt (QS/QTO2) (breathing air). RESULTS: In the postural study (n = 8) SaO2 decreased from a mean (SD) value of 89 (5)% supine to 80 (6)% erect, corresponding to QS/QTO2 28 (8)% and 44 (8)% respectively. QS/QTTc increased from 28.7 (10.3)% to 39 (14.3)%. In the lung volume study (n = 8) QS/QTTc increased from 16.6 (11.5)% at functional residual capacity to 23.3 (11.9)% at total lung capacity while QS/QTO2 increased from 19.5 (7.5)% to 25.9 (10.6)% respectively. When all measurements were compared for QS/QTTc% and QS/QTO2% (n = 32) the difference in the mean values was 2.5% (absolute) and the limits of agreement between the two methods were +38% to -18% (relative). In neither the postural nor the volume study did delta (QS/QTO2) reliably predict delta (QS/QTTc)%. CONCLUSIONS: In pulmonary arteriovenous malformations the simple physiological shunt calculated from SaO2 breathing air agreed well with the anatomical right to left shunt measured with 99mTc-MAA, but predicted poorly the changes in anatomical shunt induced by postural or lung volume changes.

Adult↗
PubMed1994

Office microbiology.

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Equipment and Supplies↗
PubMed1993

A comparison of abdominal and vaginal examinations for the diagnosis of engagement of the fetal head.

The diagnosis of engagement of the fetal head is mandatory before operative vaginal delivery is to be attempted. There is widespread belief that the fetal head is engaged in the maternal pelvis when vaginal examination reveals that the bony presenting part has reached the level of the ischial spines. However, it is also claimed that in the presence of moulding the vaginal findings may be misleading and that it may be preferable to make the diagnosis by abdominal examination of the level of the fetal head in relation to the pelvic brim. In order to evaluate the relative merits of each of these 2 systems of physical examination, a retrospective study was made of 104 cases which had been evaluated for possible operative vaginal delivery by both methods. Prediction of successful vaginal delivery was greater by abdominal criteria (94%) than by vaginal criteria (80%) (p < 0.01). When evaluated by maximum likelihood logistic regression analyses, the factor of greatest importance in determining the probability of allocation of a case to each of the engagement groups was moulding (odds ratio 2.17; 95% confidence intervals 0.75-6.27). We conclude that when these 2 methods of assessment produce different diagnoses, the major factor responsible is moulding of the fetal head. Clinical evaluation prior to operative vaginal delivery must include abdominal examination and reliance on vaginal findings alone may prove misleading when moulding is present.

Adult↗
PubMed1992

Indium-111 whole-body retention: a method for quantification of disease activity in inflammatory bowel disease.

Quantification of disease activity in inflammatory bowel disease (IBD) has been by measurement of fecal excretion of 111In-granulocytes. The difficulties of this method prompted us to evaluate quantification of whole-body 111In retention, expressed as a percentage of whole-body activity at 3 hr following injection, as an alternative method. The patient stood in front of the uncollimated gamma camera at a distance of 4 m and counts were collected over 2 min. The geometric mean was taken of posterior and anterior counts and compared with a 111In standard. The lower limit of the 95% confidence interval for whole-body retention in normals was 90%. Forty-five studies were performed on 33 patients with IBD. They were assessed in two groups, one to whom routine instructions for the collection of feces were given (Group A) but who did not always comply. The other group received oral and written instructions and were also monitored during the collection period (Group B) and reported full fecal collection. Although in Group A the correlation between fecal excretion and whole-body retention was good (r = 0.7, n = 32; p less than 0.001), in Group B the relationship between fecal excretion and whole-body retention was significantly better (r = 0.95, n = 18; p less than 0.001). On average, 111In whole-body retention was consistent with findings obtained during imaging: 111In excretion (100-whole-body retention) was 7.8% +/- 4.9% in 5 normal scans, 10% +/- 5.9% in 17 (+) scans, 22.3% +/- 8% in 20 (++) scans and 57% +/- 16% in 8 ( ) scans. We conclude that imaging is more sensitive than whole-body retention and fecal excretion in the detection of disease, but for quantification, whole-body retention is an accurate reliable alternative to fecal excretion.

Adult↗