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Biomedical subjects

D H Roberts

Publications and source records attributed to D H Roberts.

At least 37 records · Page 2Linked to original sources

Cholesterol management in general practice.

Ninety general practitioners from the Fylde coast of Lancashire responded to a questionnaire regarding lipid management, revealing that only 22% aim for a target total cholesterol of < or = 5.2 mmol/l in patients with established ischaemic heart disease. One third are reassessing the cholesterol in these patients at yearly intervals or less frequently, and 36% select 65 years or less as the upper age limit for screening. Approximately 50% of GPs screen for hypercholesterolaemia in patients with cerebral or peripheral vascular disease. Primary screening and treatment of hypercholesterolaemia within the 'at risk' asymptomatic population is well established with 72% of GPs screening hypertensives, 88% screening diabetics and almost all screening patients with an adverse family history, but the therapeutic cholesterol targets vary widely between individual practitioners.

Age Distribution↗

Balloon mitral valve dilatation as an aid to weaning from ventilatory support in patients with intractable pulmonary oedema caused by severe mitral stenosis.

Intractable pulmonary oedema in patients undergoing mechanical ventilation must be investigated as older patients with severe mitral stenosis can be rescued by balloon dilatation of the mitral valve, thus enabling elective cardiac surgery at reduced risk. We describe two such cases and discuss the role of transoesophageal echocardiography in the intensive care unit in the diagnosis and management of these patients.

Catheterization↗

Safety and effectiveness of long-term interferon gamma therapy in patients with chronic granulomatous disease.

In chronic granulomatous disease (CGD), diminished or absent neutrophil NADPH oxidase function leads to recurrent pyogenic infections and granuloma formation. In a recent randomized, placebo-controlled trail, short-term prophylactic use of recombinant human interferon gamma (rIFN-gamma 1b) reduced the risk of serious infection in CGD patients by 67%, The current study evaluated the safety and effectiveness of long-term rIFN-gamma therapy in CGD patients. Patients were treated three times weekly with rIFN-gamma and evaluated semiannually. Serious infections (requiring hospitalization and parenteral antibiotic therapy), adverse clinical events, and measures of growth and development were noted. Thirty patients were evaluated for 12 months. The total average duration of rIFN-gamma therapy was 2.5 years. Three patients developed a total of four serious infections (0.13 infections per patient year). This rate compare favorably with rates of 1.10 and 0.38 infections per patient year found in the placebo and rIFN-gamma groups, respectively, during a previous study. Common adverse events were fever (23%), diarrhea (13%), and flu-like illness (13%). No serious adverse event was attributable to rIFN-gamma therapy and no obvious effects on growth and development were observed. rIFN-gamma is a safe and effective adjunctive therapy for reducing the frequency and severity of serious infections in CGD patients.

Adjuvants, Immunologic↗

Spontaneous coronary artery dissection associated with oral contraceptive use.

A 39-year-old woman presented with acute myocardial infarction due to spontaneous dissection of the left anterior descending artery. This was treated conservatively. She had been on combined oral contraceptive pills from the age of 22. Repeat coronary angiography 7 months later revealed spontaneous complete healing.

Adult↗

Comparison of externally strapped versus implanted accelerometer- or vibration-based rate adaptive pacemakers during various physical activities.

The ability of externally strapped accelerometer- (Excel [Cardiac Pacemakers, Inc.]) and vibration-based (Activitrax [Medtronic, Inc.]) rate adaptive pacemakers to reproduce the rate response of the same implanted devices with identical programming was evaluated in ten patients by ambulatory Holter monitoring. The resting and postexercise external pacemaker rates closely resembled those of the respective implanted devices. During short bursts and more prolonged exercise, both types of strapped-on devices underestimated maximal implanted pacemaker rate response by 4%-10% when programmed to nominal rate adaptive settings. Studies evaluating chronotropic responses from either type of externally strapped activity sensor appear valid, provided the modest attenuation in maximal rate increase by this method is appreciated.

Aged↗

Comparison of sinus node response to exercise with responses from two different activity-based rate adaptive pacemakers in healthy subjects of different age groups.

The pacing rates from accelerometer-based (Excel) and piezoelectric-based (Legend) activity sensing rate adaptive pacemakers, both strapped externally in the pectoral position, were compared with sinus rate response in normal volunteers of two different age groups (group 1, mean age 35 +/- 16 years; group 2, mean age 72 +/- 9 years) during various physical activities. Both pacemakers were programmed in manufacturers' nominal rate adaptive settings. Both types of activity sensing pacemakers programmed in this way showed chronotropic deficiencies to metabolic demand in healthy young subjects and in those matching the usual age of pacemaker implant, especially during "burst" activities. These data suggest that present recommended activity sensing rate response algorithms for accelerometer and piezoelectric pacemakers are inappropriate for many physical activities.

Adult↗

Comparative evaluation of rate modulation in new generation evoked QT and activity sensing pacemakers.

Two new generation rate adaptive pacemakers, the Rhythmyx (Vitatron) using the evoked QT interval and the Legend (Medtronic) using vibration as indicators of metabolic demand, were compared for rate adaptive characteristics during different forms of exercise. While both showed improvements over previous generation pacemakers, they still show deficiencies in some aspects of rate modulation. Rhythmyx was slow to respond to changes in metabolic need and showed an "over-shoot" with increasing pacing rate on cessation of exercise. Legend was quick to adapt rate at beginning and end of exercise but showed a plateaus of rate modulation during the period of slowly increasing workload. Legend also showed only modest rate adaptation to changes in treadmill gradient and to bicycle ergometer exercise. Further developments in pacemaker technology are required if physiological rate adaptation to exercise is required.

Aged↗

Double-blind comparison of captopril with nifedipine in hypertension complicated by intermittent claudication.

In a double-blind, crossover trial 12 patients with hypertension and peripheral arterial disease were randomized to three months' treatment with captopril 25-50 mg twice daily or nifedipine SR 20-40 mg twice daily. While both treatments were equally effective at lowering blood pressure, postexercise calf blood flow availability was greater during treatment with captopril (P less than 0.04). This was not reflected in walking capacity assessed by treadmill exercise. The results suggest that both captopril and nifedipine are appropriate antihypertensive agents in patients with peripheral arterial disease.

Blood Pressure↗

Failure to establish congenital bluetongue virus infection by infecting cows in early pregnancy.

Two groups of 10 pregnant cows were inoculated with bluetongue virus type 11 at either 40 or 60 days of gestation. All the cows became infected as judged by the detection of viraemia and seroconversion but they showed no clinical signs. Seventeen of the cows produced live calves none of which showed any evidence of prenatal infection. After challenge with the same virus all the calves became viraemic and seroconverted. The response to challenge of the two groups did not differ from that of a control group challenged at the same time. It was concluded that the infection of pregnant cows in early gestation with this virus did not result in the transplacental infection of the fetuses and did not produce immunotolerant, latently infected calves.

Animals↗