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Biomedical subjects

W Reinhart

Publications and source records attributed to W Reinhart.

17 recordsLinked to original sources

Effects of exercise training on limb blood flow in patients with reduced ventricular function.

BACKGROUND: Among the factors that contribute to limiting exercise tolerance in chronic heart failure are reduced peripheral blood flow and impaired vasodilatory capacity. Exercise training improves vasodilatory capacity in normal subjects, but controlled studies of exercise training evaluating upper and lower limb blood flow rates have not been performed in patients with reduced ventricular function. Improved vasodilatory capacity could help explain how training increases exercise capacity in these patients. METHODS: Twenty patients (mean age 55 +/- 6 years) with reduced left ventricular function (mean ejection fraction 32% +/- 6%) after a myocardial infarction were randomized to a 2-month high-intensity residential rehabilitation program or to a control group and were monitored over the subsequent year. Both groups were treated according to current practice with angiotensin-converting enzyme inhibition therapy. Training began 1 month after myocardial infarction. Baseline and postischemic flow rates were measured by plethysmography in both the upper and lower limbs 1 month, 3 months, and 1 year after the infarction. Peak oxygen uptake (VO2) and cardiac output were measured before and after training, and peak VO2 was determined again after 1 year. RESULTS: After 2 months of training peak VO2 increased 25%, VO2 at the lactate threshold increased 40%, and maximal cardiac output increased from 12.1 +/- 1.6 L/min to 13.9 +/- 2.4 L/min in the exercise group (all p < 0.05), whereas no differences were observed in the control group. At the 1-year follow-up no further increases in peak VO2 were noted in either group, but the higher value persisted in the trained group. However, changes in limb flow rates were poorly related to changes in both peak VO2 and maximal cardiac output. Improvements in baseline and postischemic flow rates occurred mainly in the lower limbs and were observed in the two groups to a similar degree. CONCLUSION: Exercise training is highly effective in improving exercise capacity in patients with reduced ventricular function after myocardial infarction. These improvements parallel an increase in maximal cardiac output, but they are unrelated to vasodilatory capacity. In patients with reduced ventricular function after myocardial infarction, lower limb vasodilatory capacity improves gradually over the subsequent year, and these improvements occur irrespective of exercise training.

Adult↗

Effect of exercise training on myocardial remodeling in patients with reduced left ventricular function after myocardial infarction: application of magnetic resonance imaging.

BACKGROUND: There are conflicting reports on the effects of training on the remodeling process in post-myocardial infarction patients with ventricular damage. METHODS AND RESULTS: Twenty-five patients with reduced ventricular function (mean ejection fraction, 32.3+/-6%) after an anteroseptal or inferolateral myocardial infarction were randomized to an exercise group (n=12) or a control group (n=13). Patients in the exercise group resided in a rehabilitation center for 2 months and underwent a training program consisting of two 1-hour sessions of walking daily, along with four monitored 45-minute sessions of stationary cycling weekly. Before and after the study period, maximal exercise testing and cardiac MRI were performed. Oxygen uptake increased 26% at maximal exercise (19.7+/-3 to 23.9+/-5, P<.05) and 39% at the lactate threshold (P<.01) in the exercise group, whereas control values did not change. No differences were observed within or between groups in MRI measures of end-diastolic (187+/-47 pre versus 196+/-35 mL post in the exercise group and 179+/-52 pre versus 180+/-51 mL post in the control group), end-systolic volume (118+/-41 pre versus 121+/-33 mL post in the exercise group and 119+/-54 pre versus 116+/-56 mL post in the control group), or ejection fraction (38.0+/-9 pre versus 38.2+/-10% post in the exercise group and 37.0+/-10 pre versus 38.3+/-13% post in the control group). Myocardial wall thickness measurements at end diastole and end systole and their difference in 80 myocardial segments determined by MRI yielded no significant interactions between groups. When myocardial wall thickness measurements were classified by infarct or noninfarct areas, no differences were observed between groups over the study period. CONCLUSIONS: A high-intensity, 2-month residential cardiac rehabilitation program resulted in substantial increases in exercise capacity among patients with reduced left ventricular function. In contrast to some recent reports, the training program had no deleterious effects on left ventricular volume, function, or wall thickness regardless of infarct area.

Exercise Test↗

Effect of high intensity exercise training on central hemodynamic responses to exercise in men with reduced left ventricular function.

OBJECTIVES: The aim of this study was to evaluate the effects of high intensity exercise training on left ventricular function and hemodynamic responses to exercise in patients with reduced ventricular function. BACKGROUND: Results of studies on central hemodynamic adaptations to exercise training in patients with chronic heart failure have been contradictory, and some research has suggested that training causes further myocardial damage in these patients after a myocardial infarction. METHODS: Twenty-five men with left ventricular dysfunction after a myocardial infarction or coronary artery bypass graft surgery were randomized to an exercise training group (mean age +/- SD 56 +/- 5 years, mean ejection fraction [EF] 32 +/- 7%, n = 12) or a control group (mean age 55 +/- 7 years, mean EF 33 +/- 6%, n = 13). Patients in the exercise group performed 2 h of walking daily and four weekly sessions of high intensity monitored stationary cycling (40 min at 70% to 80% peak capacity) at a residential rehabilitation center for a period of 2 months. Ventilatory gas exchange and upright hemodynamic measurements (rest and peak exercise cardiac output; pulmonary artery, wedge and mean arterial pressures; and systemic vascular resistance) were performed before and after the study period. RESULTS: Maximal oxygen uptake (VO2max) increased by 23% after 1 month of training, and by an additional 6% after month 2. The increase in VO2max in the trained group paralleled an increase in maximal cardiac output (12.0 +/- 1.8 liters/min before training vs. 13.7 +/- 2.5 liters/min after training, p < 0.05), but maximal cardiac output did not change in the control group. Neither stroke volume nor hemodynamic pressures at rest or during exercise differed within or between groups. Rest left ventricular mass, volumes and EF determined by magnetic resonance imaging were unchanged in both groups. CONCLUSIONS: High intensity exercise training in patients with reduced left ventricular function results in substantial increases in VO2max by way of an increase in maximal cardiac output combined with a widening of maximal arteriovenous oxygen difference, but not changes in contractility. Training did not worsen hemodynamic status or cause further myocardial damage.

Cardiac Output↗

The status of marketing in the health care industry: perspectives of marketing practitioners.

To assess the scope and status of the marketing function in the health care industry, a mail survey of marketing professionals in health care organizations in the Greater Baltimore region was undertaken. Questions were designed to identify important responsibilities, required skills, evaluation factors, and major problems in the practice of health care marketing. Analytic ability was the skill identified as being most necessary to perform their job while quality of service was factor most used to evaluate their performance. Planning, service and the development of products/services were indicated as being their most important responsibility. Inadequate budget and top management's lack of knowledge of marketing were cited as the most important hindrances to effectiveness in marketing jobs. Failure of marketing in the health care industry appears to be internal to the organizations themselves, that is, in terms of how it is interpreted and applied in practice. Solutions require greater understanding of and commitment to the varied roles of marketing professionals.

Attitude of Health Personnel↗

Computerized videokeratoscopy contact lens software for RGP fitting in a bilateral postkeratoplasty patient: a clinical case report.

Computerized videokeratoscopy systems now allow interactive rigid gas permeable (RGP) fitting evaluation using fluorescein pattern simulations through updated software programs. We used Computed Anatomy's Topographic Modeling System-1 (TMS-1) Custom Design Contact Lens Program successfully to refit a symptomatic bilateral post-penetrating keratoplasty patient. No trial lenses were used. For each eye the base curve, optic zone size, and edge lift were chosen from the optimal fluorescein pattern designed and titrated on the TMS-1 unit. Lens powers were based on the patient's previous lenses and overrefraction. Dispensed lenses provided a clinically acceptable fit, good comfort, and maximal visual acuity, and no adjustments were necessary. Corneal videokeratoscopy can be successfully employed to titrate an RGP fit, even on irregular corneas.

Astigmatism↗

Fibrin glue in surgery: frequent development of inhibitors of bovine thrombin and human factor V.

We report on a 34-year-old woman whose plasma showed a marked prolongation of thrombin time (TT) (> 200 s) using bovine thrombin. The patient had previously been exposed twice to topical bovine thrombin contained in fibrin glue during cardiac surgery. TT was normal when human thrombin was used as reagent. The patient's purified IgG reacted with bovine prothrombin and bovine thrombin in immunoblotting studies but showed virtually no cross-reaction with human thrombin. In addition, following surgery, factor V clotting activity (FV:C) was reduced to 9% of normal. The inhibitor of bovine thrombin persisted over a period of more than a year, while the level of FV:C progressively returned to normal within this time period. Development of thrombin and FV:C inhibitors was also investigated in plasma of 34 consecutive patients who had undergone either cardiac surgery or neurosurgery with use of fibrin glue containing bovine thrombin. Eleven of 24 patients after cardiac surgery and two of 10 patients after neurosurgery presented with TT > or = 25 s (normal plasma 15 s). Two patients had been re-exposed to fibrin glue during cardiac re-operation and showed markedly prolonged TT (> 60 s). All 13 patients who had acquired a thrombin inhibitor also had low FV:C activity (10-60% of normal plasma), whereas FV:C activity remained in the normal range in the 21 patients with normal TT. Our findings indicate that development of inhibitors of bovine thrombin as well as co-immunization to factor V occurs frequently and is associated with the amount of applied fibrin glue and with the type of operation. Re-exposure to fibrin glue seems to enhance formation of inhibitors of bovine thrombin and human factor V.

Adult↗

Altered rheological properties of blood following administrations of tissue plasminogen activator and streptokinase in patients with acute myocardial infarction.

Tissue blood flow is determined by rheological properties of blood as well as by vascular resistance. In acute myocardial infarction patients who participated in the TIMI I trial, we compared the effects of recombinant tissue plasminogen activator (rt-PA) and streptokinase (SK) on blood rheological properties and plasma fibrinogen concentration. Blood viscosity was determined by using a coaxial cylinder viscometer at shear rates, gamma, of 0.01-200 sec-1. Red blood cell (RBC) deformability was studied by filtration through polycarbonate microsieves with pore size of 3 and 5 microns. Therapy with rt-PA resulted in slight decreases but statistically significant in blood viscosity from 5.2 +/- 0.5 to 4.9 +/- 0.4 cP (gamma = 52 sec-1), plasma viscosity from 1.36 +/- 0.09 to 1.32 +/- 0.06 cP, and plasma fibrinogen from 0.26 +/- 0.04 to 0.21 +/- 0.03 g/dl. SK therapy resulted in reductions in blood viscosity from 5.1 +/- 0.5 to 4.6 +/- 0.3 cP, plasma viscosity from 1.26 +/- 0.10 to 1.16 +/- 0.03 cP, and fibrinogen from 0.26 +/- 0.06 to 0.10 +/- 0.05 g/dl. Changes observed with SK were significantly greater than those observed with rt-PA (all p less than 0.05), and the differences persisted at 10 days after thrombolytic therapy. RBC deformability was similar in the two groups. The greater reduction of blood viscosity after SK than rt-PA suggests that, for a given degree of arterial patency, myocardial blood flow may be better maintained with SK than rt-PA in patients with acute myocardial infarction.

Blood Proteins↗

Increased resistance to membrane deformation of shape-transformed human red blood cells.

The study of shape-transformed human erythrocytes is of hematological interest since several clinical conditions are associated with erythrocyte shape changes. Using the micropipette technique, we examined the rheological behaviors of echinocytes induced by sodium salicylate or ATP depletion and of stomatocytes induced by chlorpromazine. Both the discocyte-echinocyte and discocyte-stomatocyte transformations resulted in an increased resistance to extension. Sodium salicylate-treated erythrocytes could be returned to normal morphology and normal membrane rheology by addition of chlorpromazine. We conclude that these morphological changes are associated with detrimental effects on the intrinsic membrane deformability of the human erythrocyte.

Adenosine Triphosphate↗

The effect of a single dose of propranolol on human erythrocytes in vivo.

In vitro propranolol has a profound effect on erythrocytes as indicated by a decrease of the packed cell volume and a shift to the right of the oxygen dissociation curve. Because of the lack of satisfactory in vivo studies, the effect of 80 mg propranolol and placebo was compared in twelve volunteers in a double-blind study. Although plasma propranolol concentrations varied greatly from individual to individual, all propranolol subjects demonstrated effective beta-blockade. Packed cell volume, mean cellular volume, plasma trapping after haematocrit centrifugation, P 50, 2,3-DPG, ATP, erythrocyte filterability and blood viscosity at different packed cell volumes (50% and 80%) and shear rates (11.5, 23, 46, 115 and 230 s-1) did not change significantly following administration of either propranolol or placebo. These findings are of interest in view of the use of beta-blocking agents in critically ill patients.

Adenosine Triphosphate↗

[Transitory bacteremia in rectoscopy].

A prospective study was undertaken to determine the frequency of transient bacteremia on recto-sigmoidoscopy. Blood specimens were drawn for aerobic and anaerobic bacterial culture immediately before, and 1, 5, 10, 15, 20, 25 and 30 min after the beginning of recto-sigmoidoscopy. 19 blood cultures were supposed to be contaminated. In 3 patients (6%) a positive blood culture was found with the following types of organisms: enterococci, Escherichia coli and nonhemolytic streptococci. The need for antibiotic prophylaxis in patients with valvular heart diseases or prosthetic valves is discussed. In such cases the authors propose prophylaxis with 1 g streptomycin i.m. and 3 g ampicillin by mouth 30 min before recto-sigmoidoscopy.

Anti-Bacterial Agents↗

[Proceedings: Long-term therapy with steroids].

All glucocorticosteroids available at the present time exert a wide range of actions in every single cell of every organ. It is still not possible to dissociate the therapeutically desirable effects from the undesirable side effects, and whether this goal will ever be achieved is more than questionable. Thus, chronic treatment with steroids is invariably associated with side effects, but there are a number of therapeutic rules whose strict observance may prevent a patient in chronic need of steroid treatment from developing a second, iatrogenic disease. For example, there is strong evidence that spacing the administration or oral steroids, even without changing the 24 h dosage, may substantially decrease the steroid induced side effects without loss of therapeutic action. Another promising approach has been reported in the case of steroid dependent asthmatics, many of whom may be treated by inhalations of steroid esters with strong topical but low systemic effects.

Administration, Oral↗