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Biomedical subjects

J Thornton

Publications and source records attributed to J Thornton.

At least 19 recordsLinked to original sources
PubMed1992

Effect of using protocols on medical care: randomised trial of three methods of taking an antenatal history.

OBJECTIVE: To compare the effectiveness of three methods of taking an antenatal history on the quality of obstetric care. DESIGN: Randomised controlled trial. SETTING: Antenatal clinic of St James's University Hospital, Leeds. SUBJECTS: 2424 women attending the hospital for the first (booking) visit. INTERVENTIONS: Histories were taken by midwives using an unstructured paper questionnaire, a structured paper questionnaire (incorporating a checklist), or an interactive computerised questionnaire (incorporating 101 clinical reminders). MAIN OUTCOME MEASURES: The number of clinical responses to factors arising from the antenatal booking history according to method of taking the history. Actions were categorised as medical and surgical, obstetric, personal, current symptoms and treatment, related to maternal age, and related to two common actions (cervical smear testing and dental hygiene) and were weighted for clinical importance by 10 obstetricians. RESULTS: Overall the unstructured questionnaire generated 1063 actions, the structured questionnaire 1146, and the computerised questionnaire 1122. The clinical importance of these actions was lowest for the unstructured questionnaire (overall total value score 1987 v 2182 and 2110 for the structured and computerised questionnaires respectively). The structured questionnaire was better than the computerised questionnaire in the medical and surgical (total value score 191 v 184), obstetric (275 v 241), and personal (430 v 360) categories but inferior in the current symptoms category (179 v 191). CONCLUSION: Structured questionnaires (computerised or paper) provide more and better information, and their use improves clinical response to risk factors. Computerised systems offer no further advantage in antenatal clinics.

Clinical Protocols↗
PubMed1992

Adenosine is an endogenous protectant against stunning during repetitive ischemic episodes in the heart.

To investigate whether adenosine receptor blockade alters the response to serial coronary occlusions in the rabbit heart, we measured changes in segment length with ultrasonic dimension gauges placed in the field of a coronary branch. The coronary branch was subjected to four 5-minute occlusions, each separated by 10 minutes of reperfusion. In control hearts, the percentage of segment shortening fell from 15.7% to 9.3% after release of the first occlusion with no further deterioration after each of the subsequent three occlusions. In hearts in which adenosine receptors were blocked with PD 115,199, a potent blocker of both A1 and A2 receptors, segment shortening again recovered to about two thirds of the preischemic value during the reperfusion period after the first occlusion. Each subsequent occlusion, however, resulted in a further deterioration of function to the extent that shortening was less than 20% of the preischemic value during reperfusion after the fourth occlusion. Therefore the first occlusion of a series of four occlusions, while mildly stunning the heart, also preconditions the myocardium against further stunning by subsequent occlusions. Because that protection was when adenosine receptors were blocked, adenosine must play an important role in the mediation of this protective effect.

Adenosine↗
PubMed1992

Body-fat measurement in patients with acquired immunodeficiency syndrome: which method should be used?

Malnutrition is common in patients with acquired immunodeficiency syndrome (AIDS), which distorts the chemical contents in the fat-free mass (FFM) and alters the assumptions underlying the traditional methods for calculating body-fat content so that such measurements may not be accurate. In vivo neutron-activation analysis (IVNA) measures FFM independently of the traditional assumptions, thereby providing more accurate measurements of body fat. We compared seven methods for measuring body fat in 18 male patients with AIDS: IVNA, total body water (TBW by 3H2O dilution), total body potassium (TBK by 40K counting), dual-photon absorptiometry (DPA), bioelectrical impedance analysis (BIA), and two well-calibrated anthropometric methods. FatTBW and fatDPA were not significantly different from fatIVNA. FatTBW gave the highest correlation with fatIVNA and the smallest SEE of +/- 1.8% (1.1 kg). The traditional and widely available TBW and the newer DPA method provide reliable estimates of fatIVNA in patients with AIDS.

Absorptiometry, Photon↗
PubMed1992

Protection from reperfusion injury by preconditioning hearts does not involve increased antioxidant defenses.

Preconditioning the heart with 5 min of ischemia renders the heart very resistant to infarction from subsequent ischemia by an unknown mechanism. We investigated whether the protective effect of preconditioning might be related to an increase in rabbit heart antioxidant defenses. The antioxidant activities of catalase, glutathione peroxidase, Mn superoxide dismutase, Cu,Zn superoxide dismutase, glucose-6-phosphate dehydrogenase, glutathione reductase, and total glutathione were measured in ischemic and normal regions from both control and preconditioned rabbit hearts. All hearts experienced 30 min regional ischemia and 5 min reperfusion. None of the antioxidant enzymes changed in activity when comparing nonischemic and postischemic zones in either nonpreconditioned or preconditioned hearts. Total glutathione, however, was reduced in reperfused zones and showed better preservation in preconditioned hearts. To determine whether this preservation resulted from a higher value at the onset of reperfusion or slower washout during reperfusion, we analyzed a second group of nonreperfused hearts after 30 min ischemia. The hearts had normal glutathione content in both ischemic and nonischemic zones of either preconditioned or control hearts. The most likely explanation is that preconditioned hearts experienced less washout of glutathione simply because they were less injured. We therefore conclude that enhancement of antioxidant defenses is not the mechanism of preconditioning.

Adaptation, Physiological↗
PubMed1992

Needs of well siblings of persons with schizophrenia.

The practical concerns of well siblings of persons with schizophrenia were examined in a descriptive study that included a needs assessment survey and a workshop designed to increase well siblings' knowledge about schizophrenia. A questionnaire focusing on needs for information, support, and practical skills was completed by 88 well siblings and 19 of their spouses. The results indicated a desire for more specific information about schizophrenia, particularly prognosis, and difficulties in communicating and problem solving with siblings with schizophrenia. Although respondents to the questionnaire were neutral about the need for support from other well siblings, participants at the workshop indicated that they found the opportunity to meet and share experiences with other well siblings to be the workshop's strongest feature. The study indicates that well siblings of persons with schizophrenia have specific needs that may differ from those of other family members.

Activities of Daily Living↗
PubMed1992

A prospective randomized trial of laparoscopic versus open appendectomy.

BACKGROUND: Laparoscopic appendectomy is feasible, but whether it confers any advantage to patients with acute appendicitis is not known. We performed a randomized controlled trial to compare results of laparoscopic and open appendectomy in patients with signs and symptoms suggesting acute appendicitis who were seen by one surgical team. METHODS: Sixty-two consecutive patients were randomized, 30 to laparoscopy and 32 to a classical open appendectomy. Postoperative recovery, complications, and return to normal activities were compared in the two groups. RESULTS: The laparoscopy group were discharged earlier (2.5 vs 3.8 days, p less than 0.01). Postoperative complications were more frequent after open appendectomy. Follow-up showed less pain, shorter bed stay at home, and faster return to work and sport after laparoscopic appendectomy. CONCLUSIONS: This prospective randomized study shows that laparoscopic appendectomy is superior to open appendectomy in terms of hospital stay, postoperative complications, and return to normal activities and is recommended as the approach of choice in the management of acute appendicitis.

Adult↗
PubMed1991

Comparison of dual-photon absorptiometry systems for total-body bone and soft tissue measurements: dual-energy X-rays versus gadolinium 153.

A total of 81 subjects (41 males and 40 females) were scanned by dual-photon absorptiometry by 153Gd source (DPA; Lunar DP4) and by dual-energy x-ray absorptiometry (DEXA; Lunar-DPX) within a 24 h period. Total-body bone mineral density (TBMD), calcium content (Ca), and soft tissue mass (ST) were determined with a precision of about 1-1.5% using DPA and 0.5-1.0% using DEXA. Measurements of TBMD, Ca, ST, bone area (area), percentage fat, and regional bone mineral densities (BMD) were compared. Paired t-tests showed small but significant differences between all measurements. Correlations (r) for TBMD, Ca, area, ST, percentage fat, arm BMD, leg BMD, and trunk BMD were 0.99, 0.99, 0.97, 0.99, 0.97, 0.99, 0.99, and 0.98. There were small systematic differences for TBMD (less than 1%), calcium (3%), bone area (3%), soft tissue mass (7%), and percentage fat (9%) between the two approaches. Regression equations are given relating these measurements.

Absorptiometry, Photon↗
PubMed1991

Bone mineral density and mass by total-body dual-photon absorptiometry in normal white and Asian men.

Total body bone mineral density, total body bone mineral mass (TBBM), and bone mineral densities (BMD) in seven different regions of the body were measured in 238 normal men (154 Whites and 84 Asians), age 22-94, using dual-photon absorptiometry. Although Asian men had lower TBBM and BMD in all regions (p less than 0.05) except the arms, when multiple regression was done with body weight, height, and age, no significant differences were found between Asians and Whites for bone measurements. Thus lower bone mineral densities and bone mineral mass in Asian males compared to White males appear to be due to differences in height and weight rather than to ethnic differences. The two groups were combined to derive multiple regression equations for TBBM, total-body BMD, and regional BMD. Age, weight, and height were significant in the multiple regression equations for TBBM, ribs BMD, and legs BMD. Age and weight, but not height, were significant for total-body BMD, trunk BMD, spine BMD, arm BMD, and pelvis BMD. Weight, but neither height nor age, was significant for head BMD. These reference normal bone mineral density and bone mineral mass standards are appropriate for both Asian and White males when adjusted for weight, height, and age.

Absorptiometry, Photon↗
PubMed1991

Protection against infarction afforded by preconditioning is mediated by A1 adenosine receptors in rabbit heart.

BACKGROUND: Preconditioning (5 minutes of ischemia followed by 10 minutes of recovery) renders the heart very resistant to infarction from subsequent ischemia. This study tests whether adenosine receptors might mediate preconditioning protection. METHODS AND RESULTS: We examined the effect on infarct size of pretreatment with either of two adenosine receptor antagonists in both control and preconditioned in situ rabbit hearts. Hearts underwent 30 minutes of regional ischemia plus 3 hours of reperfusion, and infarct size was measured with tetrazolium. Infarct size averaged 39% of the zone at risk in controls but only 8% in preconditioned hearts. Preconditioned and nonpreconditioned hearts receiving either blocker had infarcts not different in size from the controls. A 5-minute intracoronary infusion of adenosine was as effective as 5 minutes of ischemia in protecting parabiotically perfused isolated hearts against infarction from a 45-minute ischemic insult. Similarly, intracoronary infusion of N6-1-(phenyl-2R-isopropyl)adenosine, an A1-selective adenosine receptor agonist, at a dose that delayed conduction but did not dilate the coronary vessels, also limited infarct size. The protection disappeared when we reduced the coronary concentration of drug by intravenous infusion of adenosine, indicating that cardiac rather than peripheral receptors were involved in the protection. CONCLUSIONS: We conclude that adenosine released during the preconditioning occlusion stimulates cardiac A1 receptors, which leaves the heart protected against infarction even after the adenosine has been withdrawn.

Adenosine↗
PubMed1990

Inhibition of protein synthesis does not block myocardial protection afforded by preconditioning.

It is currently unknown how preconditioning the heart with brief periods of ischemia makes it resistant to infarction from a subsequent ischemic insult. The protein synthesis inhibitors, cycloheximide and actinomycin D, were used to determine whether preconditioning involves synthesis of a protective protein. Ischemia was produced by occlusion of a branch of the left coronary artery in open-chest anesthetized rabbits. All groups were subjected to 30 min of ischemia followed by 3 h of reperfusion. The first two groups served as noninhibited controls. Group 1 was subjected to ischemia with no preconditioning. Group 2 was preconditioned with two 5-min ischemic periods each followed by 10 min of reperfusion, before the 30-min ischemic period. Groups 3 and 4 were the same as groups 1 and 2, respectively, except that cycloheximide was administered before coronary occlusion. Groups 5 and 6 were also the same as groups 1 and 2 except that actinomycin D was administered before coronary occlusion. After 3 h of reperfusion all hearts were removed and the size of the ischemic zone and infarct were determined. The percent of the ischemic zone infarcted was small and similar in all preconditioned groups (3.3 +/- 1.1% for group 2, 7.4 +/- 3.3% for group 4, and 0.5 +/- 0.7% for group 6). All nonpreconditioned groups had large infarcts with no differences between groups (39.0 +/- 8.5% for group 1, 31.6 +/- 6.3% for group 3, 30.8 +/- 5.9% for group 5). Because neither cycloheximide nor actinomycin D could block protection afforded by preconditioning, it seems unlikely that synthesis of a protective protein is the mechanism of protection.

Animals↗
PubMed1989

Open-trial maintenance pharmacotherapy in late-life depression: survival analysis.

We report preliminary findings from an ongoing, open trial of maintenance nortriptyline pharmacotherapy in 27 elderly depressed patients (median trial length: 18 months). While patients were on maintenance nortriptyline (mean dose: 50 mg/day) with steady-state plasma levels in the range of 50-150 ng/ml, 58% of Q-6 monthly ratings on the Hamilton Rating Scale for Depression have been 10 or lower, Folstein Mini-Mental State ratings have remained above 27, and a minimal level of side effects with no increase over time has been observed. Four of 27 patients (14.8%) have suffered recurrences and have required rehospitalization at 6, 9, 10, and 13 months. Survival analysis showed an 85% survival rate (without recurrence) at 12 months and 81.5% at 18 months. Mean survival time without recurrence is 21.3 months to date. Although our pilot experience with maintenance nortriptyline in late-life depression appears more favorable than outcomes reported in earlier naturalistic studies (where no attempt was made to keep patients in systematic maintenance therapy), the need for controlled studies of maintenance therapies in late-life depression is nonetheless underscored by the current data and other naturalistic data from the United Kingdom.

Aged↗
PubMed1989

Muscular adaptation of horses during intensive training and detraining.

Five horses were studied during a five-week regime of controlled intensive daily training on a high-speed treadmill followed by five weeks of detraining. Muscle biopsies were taken weekly from both the right and left gluteus muscle and from the sternocephalicus muscle before, and at the end of, the training and detraining periods. Histochemical and biochemical analyses of the sternocephalicus muscle showed no metabolic adaptation with either training or detraining. No significant differences were observed in any of the analysed parameters in the gluteus muscle between contralateral sites. Glycogen levels decreased by 10 to 15 per cent after one to two weeks of training, remained low during the training period and increased to pretraining levels after one week's cessation of training. Citrate synthase activity increased rapidly and was 27 per cent higher after one week and 42 per cent higher after five weeks of training. Lactate dehydrogenase activity decreased by 15 per cent during this period. The changes seen in these enzyme levels persisted during the detraining period. No alterations were seen in fibre type composition but type IIA fibre areas decreased by 19 per cent after five weeks training and capillary density increased by 17 per cent. It is concluded that a period of intensive training will rapidly increase the oxidative capacity and the capillary density in an actively working muscle, and that these metabolic adaptations are well maintained during a subsequent period of detraining.

Animals↗
PubMed1989

Tardive dyskinesia: a five year follow-up.

A group of chronic schizophrenic patients receiving prolonged treatment with neuroleptics was assessed in 1978 at an outpatient clinic to determine the prevalence of Tardive Dyskinesia. Those with TD were reassessed after two and five years with regard to change in TD severity. The Smith scale was used every time and, on the last assessment, the AIMS scale and videotaped interviews were added. Because of the high attrition rate, results, though interesting, cannot be generalized.

Adult↗
PubMed1989

Cervical screening in the workplace.

In an attempt to improve cervical cytology screening uptake in women aged over 40, a mobile screening unit was used to make screening easily available to women at work. This service was organized jointly between the District Health Authority, the Women's National Cancer Control Campaign and the South West Thames Regional Cancer Organization, and was offered to all companies employing at least 25 women. Thirty-nine out of 82 companies accepted the offer. Among those companies which were able to supply a register of their employees aged over 40, 91 per cent of eligible women attended the mobile clinic. The clinic doctors followed District guidelines in not taking smears from women who had been screened and found negative within the previous three years, or who had had a hysterectomy for an unrelated reason. Of the 1038 women who attended the clinic, cervical smears were taken from 568 (55 per cent). Fifteen women were found to have cervical neoplasia, of whom nine had either never been screened before or had last been screened more than five years previously; a further two women (one of whom was found to have early invasive cancer) had previously had an abnormal smear for which the recommended follow-up had not been done. It was not possible to quantify the benefits of other tests (clinical breast examination, blood pressure, urinalysis and gynaecological examination) included in the screening clinic, but they were popular with the women attending. Provided that the health authority is involved in the planning and organization of workplace screening, it can be a valuable adjunct to improving screening coverage, particularly for women aged over 40.

Adolescent↗
PubMed1989

A randomized, double-blind, placebo-controlled investigation of the safety of intravenous immune globulin administration to preterm neonates.

Intravenous immune globulin (750 mg/kg), or an equivalent volume of a placebo, was administered during the first week of life, in a randomized trial, to 20 preterm neonates weighing 710 to 1800 g. A variety of laboratory and clinical values were measured serially and analyzed for possible untoward effects. Serum IgG levels were also determined serially. No differences in heart rate, respiratory rate, urine output, blood glucose, serum osmolality, BUN, SGPT, pH, blood gasses, serum electrolytes, total or direct bilirubin, blood leukocyte concentration, absolute neutrophil count, or blood platelet concentration were observed between the intravenous immune globulin (IVIG) and placebo recipients before or following IVIG administration. The red blood cell concentration of IVIG recipients diminished transiently and only slightly (P less than .05). Serum IgG levels increased from 503 +/- 162 mg/dL (X +/- SD) to 1492 +/- 201 mg/dL 15 minutes after the IVIG administration (P less than .001). After 8 days, serum IgG levels were still elevated, at 675 +/- 297 mg/dL. All patients randomized to receive the placebo experienced a diminution in serum IgG over this 8-day period (P less than .01). All 20 patients survived and none in either group had a documented nosocomial infection. This study suggests that IVIG can safely be administered to preterm neonates, resulting in serum IgG levels comparable to those of term infants.

Blood Chemical Analysis↗