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Biomedical subjects

N Roberts

Publications and source records attributed to N Roberts.

At least 145 records · Page 8Linked to original sources
PubMed1989

Eating and mood disorders in young children.

This article addresses issues emerging from research and clinical work done with young children who develop eating and mood disorders. A literature review and vignettes of anorexia nervosa in prepubertal children are presented, and research on the relationship between eating disorders and mood disorders is examined. Three cases of prepubertal children with growth problems and features of eating and mood disorders and a developmental model of eating disorders and their relationship to mood disorders are explored. In conclusion, a series of questions and suggestions for research and therapy are posed about young children with eating and mood disorders and the relationship between them.

Adolescent↗
PubMed1988

Effects of angiotensin and angiotensin blockade on coronary circulation and coronary reserve.

Angiotensin is a potent coronary vasoconstrictor, but little is known of the effects of long-term activation of the renin-angiotensin system on coronary reserve in humans. The effects of exercise on coronary hemodynamics were determined in eight patients with mild essential uncomplicated hypertension, before and after treatment with furosemide (50 mg, to ensure activation of the renin-angiotensin system). Coronary sinus blood flow was measured by thermodilution technique, intra-arterial blood pressure was measured from the ascending aorta, and plasma renin activity was determined by radioimmunoassay. Oxygen supply and demand were derived (using coronary sinus blood flow multiplied by the arteriovenous oxygen difference to equal oxygen supply and heart rate multiplied by the mean systolic blood pressure to equal oxygen demand) both at rest and during isometric exercise (handgrip to 50 percent of maximal effort for three minutes). The study was a single-blind crossover (furosemide versus placebo) design. Furosemide produced a significant reduction in coronary sinus blood flow, associated with an increase in coronary vascular resistance. Changes in mean arterial pressure and heart rate were insignificant. Slight reductions in plasma volume and mean right atrial pressure were observed. During isometric exercise, the increase in oxygen supply for a given increment in oxygen demand was attenuated by furosemide. The contribution of the renin-angiotensin system to this effect was determined by the short-term administration of 25 mg of the angiotensin converting enzyme inhibitor captopril. Forty-five minutes after oral captopril, coronary reserve was restored to pretreatment values. In conclusion, furosemide modulates coronary reserve, and it is likely that this is because furosemide mediates activation of renin-angiotensin system, thus reducing the vasodilatory capacity of the coronary arteries.

Adult↗
PubMed1988

Cardiogenic hypertension in maturing dogs.

The purpose of this study was to evaluate whether the heart can induce high blood pressure by maintaining an inappropriately elevated cardiac output/body weight ratio during growth. Direct (femoral artery) mean arterial pressure (MAP), heart rate, cardiac output/body weight ratio (as defined by M-mode echocardiography), and total peripheral vascular resistance were measured and calculated every 2 months in nine conscious dogs during development from 2 to 10 months of age. In four dogs a J-shaped catheter for atrial pacing was chronically implanted at the age of 3 months, and their hearts were permanently paced at 130 beats/min until maturity. The aim of atrial pacing was to prevent the natural slowing of the heart rate and, consequently, to maintain a cardiac output/body weight ratio that was inappropriately high in relation to age during growth. Five dogs were studied as controls. No hemodynamic differences were observed until the age of 4 months. From the age of 5 to 10 months heart rate was kept at 130 beats/min by atrial pacing in the atrially paced group, and the mean cardiac output/body weight ratio did not decrease (196 +/- 24 vs 191 +/- 34 [SE] ml/min/kg). MAP rose from 62 +/- 4 to 116 +/- 8 mm Hg, and total peripheral resistance increased from 0.34 +/- 0.07 to to 0.61 +/- 0.09 mm Hg/ml/min/kg.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
PubMed1987

The immunologic detection and characterization of cartilage proteoglycan degradation products in synovial fluids of patients with arthritis.

Antibodies were used in radioimmunoassays with gel chromatography to detect the hyaluronic acid-binding region, core protein, and keratan sulfate of human cartilage proteoglycan in the synovial fluids of patients with rheumatoid arthritis, juvenile rheumatoid arthritis, and osteoarthritis. All fluids contained proteoglycan that was mainly included on Sepharose CL-4B; this result indicates cleavage of proteoglycan (which is normally excluded). The hyaluronic acid-binding region was the smallest and most commonly detected fragment. It was relatively free of keratan sulfate and core protein, and it could sometimes bind to hyaluronic acid. Other larger fragments containing core protein and/or keratan sulfate were detected in every fluid.

Aggrecans↗
PubMed1987

Human renovascular effects of dopexamine hydrochloride: a novel agonist of peripheral dopamine and beta 2-adreno-receptors.

The effects of dopexamine on the renal circulation have been examined to show whether any augmentation of renal blood flow (RBF) was secondary to the effect of the drug on cardiac output (CO) or whether it had any additional direct renal vasodilator activity. Eight male patients with mild to moderate hypertension, who were undergoing renal vein catheterization for renin estimation, were studied. Dose related increments in RBF (baseline (B) = 504 ml X min-1; after treatment (D) = 605 ml X min-1), CO (B = 5.9 l X min-1; D = 6.7 l X min-1), heart rate (B = 77 beats/min; D = 100 beats/min) and systolic blood pressure (B = 143 mmHg; D = 166 mmHg) were observed on administration of dopexamine 3 micrograms X kg-1 X min-1, with insignificant changes in diastolic blood pressure (B = 84.4 mmHg; D = 90 mmHg) and total peripheral resistance (B = 17.85; D = 17.25 Units). There was a slight but significant reduction in renal vascular resistance (B = 20.59, D = 18.75). The ratio of RBF to CO (%) confirmed that the increase in RBF due to dopexamine hydrochloride was greater that attributable to the increase in CO or perfusion pressure alone (RBF/CO B = 8.5%, D = 9%), consistent with selective renal vasodilatation. The fall in renin activity and lack of systemic vasodilatation suggest that this was a DA1-receptor mediated effect.

Adrenergic beta-Agonists↗
PubMed1987

The relationship between anxiety and depression in children: rating scales and clinical variables.

The present study examined the relationship between anxiety and depression in children in the context of proposed adult models. The results support the qualitative distinction between anxious and depressed patient groups on subsets of rating scale measures and clinical variables. In contrast to anxious children who were younger, (day patients) had been ill for longer than one year, presented with behavioral problems, and were low on observer ratings of depressive symptoms; depressed children were older, (inpatients) had been ill for less than one year, presented with emotional problems and were high on observer ratings of both anxious and depressive symptoms. The finding that the older depressed children were concurrently anxious while the younger anxious children were not concurrently depressed is discussed from the viewpoint of a hypothesized temporal sequence between anxiety and depression. The implication of this and other related findings are discussed in regard to their importance for differential diagnosis and prognosis.

Adolescent↗
PubMed1987

Converting-enzyme inhibition and coronary blood flow.

The effects of converting-enzyme inhibition (25 mg oral captopril) on coronary hemodynamics in the presence and absence of activation of the renin-angiotension system were studied in 10 patients with mild essential hypertension with no evidence of ischemic heart disease. Coronary blood flow was determined by thermodilution before and after 1 week of diuretic therapy in six patients and before and after placebo in four patients. The diuretic (50 mg/day furosemide) reduced coronary blood flow and increased coronary vascular resistance; in these same patients, captopril reduced mean arterial pressure and the rate-pressure product but increased coronary flow significantly. There was no change in any of these variables after captopril in the placebo group. Similar results were obtained in normotensive rats treated with hydrochlorothiazide; the increase in coronary flow after captopril correlated significantly with the control plasma renin activity. These results in hypertensive humans and normotensive experimental animals indicate that diuretic therapy reduces coronary blood flow significantly, and angiotensin can play a significant role in modulating coronary vascular resistance under conditions associated with activation of the renin-angiotensin system.

Adult↗
PubMed1987

Treatment of major affective disorder with fluvoxamine.

A placebo-controlled, double-blind study of 63 inpatients with major affective disorder was performed to compare the safety and efficacy of fluvoxamine and imipramine. Results indicate that fluvoxamine and imipramine are superior to placebo and demonstrate a trend toward superiority of fluvoxamine over imipramine. Fluvoxamine was generally well tolerated in most patients.

Adult↗
PubMed1987

Treatment of acute bacterial peritonitis: a trial of imipenem/cilastatin against ampicillin-metronidazole-gentamicin.

Imipenem/cilastatin at a dose of 0.5 g six hourly was compared to conventional combination therapy with ampicillin 0.5 g six hourly, metronidazole 0.5 g eight hourly and gentamicin 80 mg eight hourly (with dose adjustment by trough and peak serum levels) in the treatment of severe intra-abdominal infections. All antibiotics were given intravenously. Forty-five patients entered the trial. Of the 19 evaluable patients in the imipenem/cilastatin group, 16 were clinically cured with five microbiological successes and two failures. Of 24 evaluable patients in the combination group, 22 were clinically cured with one microbiological success and one failure. One patient in each group suffered an adverse effect. Patients in the I/C group tended to be older with more women and more severe infections. The origin of peritonitis was similar. I/C did not differ from combination therapy in efficacy or safety and was comparable in cost. However, I/C was easier to administer than combination therapy and there was no need for serum concentration monitoring.

Adolescent↗
PubMed1987

Immunodetection and characterization of the degradation of cartilage proteoglycans in vitro and in vivo.

The large aggregating cartilage proteoglycans can be detected immunologically using antibodies directed against the hyaluronic acid-binding region, core protein, keratan sulfate, chondroitin sulfate, and hyaluronic acid. With radioimmunoassays we have detected proteoglycans released from adult human articular cartilage in vitro and in vivo. In vitro cleavage appears to occur mainly adjacent to the hyaluronic acid binding region with the release of the rest of the molecule. Two distinct populations have been observed, the larger of which is chondroitin sulfate-rich and the smaller keratan sulfate-rich. Although they are a little smaller and probably aggregate less with hyaluronic acid, these populations correspond in size and composition to two similar populations detected in situ in healthy adult human articular cartilage. In vivo studies of synovial fluid have revealed that the proteoglycan fragments are smaller and the most commonly detected fragment is the hyaluronic acid binding region. This suggests that in vivo further degradation occurs, probably due to degradation mediated by the inflamed synovium and polymorphonuclear leucocytes present in the synovial fluid of inflamed joints.

Binding Sites↗
PubMed1986

Psychological factors associated with disability in arthritis.

A sample of chronically disabled arthritic patients was studied in 1981, and again in 1983, using a questionnaire which included attitudinal and mood items. The majority of patients had high pain and disability, and this did not significantly change between 1981 and 1983. The questionnaire was able to significantly discriminate between subjective disability and pain groups. This discrimination was more accurate than that made by orthopaedic surgeons using physical ratings alone, and possible 'good coping' and 'bad coping' profiles emerged.

Adaptation, Psychological↗
PubMed1985

Right ventricular infarction with shock but without significant left ventricular infarction: a new clinical syndrome.

Right ventricular infarction has been described as concurrent with infarction involving the inferior (posterior) aspect of the left ventricular free wall and adjacent interventricular septum. Patients with right ventricular infarction typically show the ECG changes of inferior infarction in leads II, III, and aVF. This report describes two patients with right ventricular infarction but without changes in the QRS complex of the ECG, indicating an inferior infarct of the left ventricle. An autopsy-proven infarct of the right ventricular free wall with neither QRS nor other clinical evidence of left ventricular involvement was responsible for cardiogenic shock and death in one patient. This observation led to a review of a computerized data bank containing records of patients who had undergone cardiac catheterization to determine if there were other patients with clinical criteria suggesting right ventricular infarction without QRS changes of left ventricular infarction. One of the 167 patients with a history of a myocardial infarction also met the following clinical criteria: (1) transiently elevated total creatine kinase and creatine kinase myocardial band; (2) diffuse ST segment elevation without QRS changes indicative of left ventricular infarction on the ECG; (3) normal left ventricular function; (4) hemodynamic evidence of right ventricular dysfunction; and (5) cardiogenic shock.

Aged↗
PubMed1984

Health beliefs and rehabilitation after lumbar disc surgery.

Thirty per cent of patients fail to rehabilitate after back surgery. Pre-operative physical assessment cannot reliably identify these patients. A questionnaire assesses the health beliefs and extent of rehabilitation in 200 patients who have undergone a laminectomy. Objective medical data and ten subjective scales are analyzed, which correlate very highly with quality of rehabilitation. The questionnaire identifies 'at risk' individuals far better than objective physical findings, and it makes specific pathological attitudes clear. These attitudes can be used to direct existing post-operative care resources in an efficient way.

Adult↗
PubMed1983

Prevalence and clinical correlates of pulmonary arterial hypertension in progressive systemic sclerosis.

Forty-nine patients with progressive systemic sclerosis who had undergone extensive studies including pulmonary artery catheterization as part of an ongoing prospective study of the natural course of progressive systemic sclerosis were evaluated. The overall prevalence of pulmonary arterial hypertension in this population of patients with progressive systemic sclerosis was 33 percent, and among 10 subjects with the CREST syndrome the prevalence of pulmonary hypertension was 50 percent. The relation between pulmonary arterial hypertension documented at catheterization and abnormal results of noninvasive studies suggesting pulmonary hypertension, including physical examination, chest x-ray, electrocardiography, echocardiography, single-breath diffusing capacity, and vital capacity, was studied. Diffusing capacity was significantly lower in those patients with definite pulmonary hypertension (mean pulmonary artery pressure of 22 mg Hg or more) compared with those with a normal mean pulmonary artery pressure, and a diffusing capacity below 43 percent of predicted showed the greatest sensitivity (67 percent) of any single diagnostic test in detecting definite pulmonary hypertension. Chest x-ray suggesting pulmonary hypertension was the least sensitive of the tests evaluated, but showed the greatest specificity (100 percent) in identifying patients with pulmonary hypertension. A classification matrix based on discriminant function analysis utilizing the combination of diffusing capacity below 43 percent of predicted and chest x-ray and electrocardiographic findings correctly identified 75 percent of patients with definite pulmonary hypertension and 97 percent of patients with a normal pulmonary artery pressure, but failed to identify correctly patients with mild pulmonary hypertension (mean pulmonary artery pressure of 20 mm Hg). These findings indicate that specific noninvasive studies are helpful in assessing the likelihood of normal or definitely elevated pulmonary artery pressures in patients with progressive systemic sclerosis, but patients with mild pulmonary hypertension are not likely to be identified by these noninvasive studies.

Adult↗