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Biomedical subjects

H Mueller

Publications and source records attributed to H Mueller.

At least 73 records · Page 4Linked to original sources
PubMed1982

Desmoplakins of epithelial and myocardial desmosomes are immunologically and biochemically related.

Guinea pig antibodies against desmoplakins from bovine muzzle epidermis showed specific reaction in several epithelial tissues with desmoplakin I (Mr 250,000) and desmoplakin II (Mr 215,000). By immunofluorescence microscopy, prominent punctate staining was observed in various lines of cultured epithelial cells, revealing desmosomal junctions at sites of established cell-to-cell contacts as well as hemidesmosomes and internalized desmosome-derived membrane domains. On frozen tissue sections punctate staining was observed along plasma membranes of epithelial cells, and electron microscopy using the immunoperoxidase technique revealed that the antibodies were specifically localized at the plaques associated with desmosomes and hemidesmosomes. Of a large number of non-epithelial cells examined positive staining was only observed on desmosome-like junctions of myocardial cells and Purkinje fiber cells. In both epithelial and myocardial tissues the antibodies showed a broad range of cross-reactivity between diverse vertebrate species such as man, cow, rodent, and chicken, indicating that desmoplakins contain determinants strongly conserved during evolution. When binding of these antibodies to cytoskeletal polypeptides separated by gel electrophoresis and blotted on nitrocellulose paper sheets was examined, specific reaction was noted with desmoplakin I and, to a variable degree, also desmoplakin II from various epithelial cells. Reaction was also observed with a myocardial polypeptide from bovine and human hearts which had a similar Mr value (250,000) and isoelectric pH range as desmoplakin I. We conclude that desmoplakins are the major proteins present in the desmosomal plaques of both epithelial and myocardial cells and that the desmoplakin polypeptides present in these two different cell types are very similar, if not identical.

Animals↗
PubMed1977

Use of salt bridge in rhythm analysis.

Filling a catheter with electrolyte solution converts it to a conductor and allows the safe recording of an electrogram from near or within the right atrium. This technic is very useful in localizing the internal position of a cardiac catheter and particularly in rhythm analysis. Four cases are presented to review the value of this salt bridge technic.

Adult↗
PubMed1976

Propranolol in acute myocardial infarction in man: effects of haemodynamics and myocardial oxygenation.

Improvement of myocardial oxygenation is a major goal in the treatment of ischaemic heart disease. Propranolol, 0-1 mg/kg intravenously, was administered to 20 patients with acute myocardial infarction without clinical evidence of left ventricular failure. The most important haemodynamic response was a substantial decrease in myocardial contractility. This was reflected by a fall in cardiac index (average of 0-4 l/min/M2, P less than 0-001) and of arterial mean pressure (average of 16 mmHg, P less than 0-001) with little change in systemic vascular resistance. Heart rate, not strikingly increased at the control state in the majority of patients, decreased an average of 7 beats/minute (P less than 0-001). Pulmonary wedge pressure varied; it decreased in 6 patients with high values (greater than 15 mmHg) prior to propranolol. These changes in wedge pressure in the presence of decreased contractility are probably related to improved left ventricular compliance, produced by propranolol. Propranolol markedly improved myocardial metabolism. Arterial-coronary sinus oxygen difference decreased an average of 0-72 ml/100 ml (P less than 0-001). Myocardial lactate production shifted to extraction (average of -8% to 14%) or the rate of lactate extraction increased (average of 20% to 29%). Coronary blood flow decreased an average of 13 ml/100 g/min (P less than 0-001). The finding, that myocardial metabolism improved, suggests that decrease in coronary blood flow was mediated by reduced myocardial oxygen requirements. None of the 20 patients developed left ventricular failure or other complications related to beta-adrenergic blockade. Severe chest pain, unresponsive to conventional therapy in four patients, was relieved by propranolol. These findings demonstrate that acutely administered propranolol improves myocardila oxygenation in patients with uncomplicated acute infarction without endangering perfusion of other vital organs.

Adult↗
PubMed1975

Pyloromyotomy: Does surgery in infancy increase allergy?

One recently published article and several presentations at international meetings have suggested that there is an increased incidence of allergic and asthmatic manifestations, as compared with the general population, if a child undergoes surgery before the age of 2 years. The study explores the incidence of asthma and allergy in a group of patients who presented with pyloric stenosis. All of these underwent surgery. The technique of the study was a retrospective telephone review and the response rate was approximately 40%. The data show that there is no increase in the incidence of allergy or asthma in this population as compared with nationally reported figures.

Adolescent↗
PubMed1975

New manual and automated method for determining activity of creatine kinase isoenzyme MB, by use of dithiothreitol: clinical applications.

The method is based on the selective activating capacity of dithiothreitol on creatine kinase isoenzyme MB, after isoenzyme MM is activated by glutathione. Isolated isoenzymes MM and MB of human and canine origin were assayed individually and in mixtures of known activities. When glutathione was present in the assay medium the activity of each isoenzyme could be measured individually, but glutathione did not activate isoenzyme MB if it was present in a mixture with MM. Dithiothreitol, added to the serum before assay, activated the isoenzyme MB in the mixture. Values for MB activities obtained for isolated isoenzyme MB and for the isoenzyme mixture after dithiothreitol was added averaged 110 and 111 U/liter, respectively (r = 0.998; y = 1.007 x + 0.298; n = 10). In the serum of 40 patients with documented acute transmural myocardial infarction, the mean proportion of isoenzyme MB activity measured in this way was 5.5% (coefficient of variation, 7.7%). Isoenzyme MB activities measured by use of dithiothreitol compared well with those obtained by conventional electrophoresis/spectrophotometry (r = 0.998; y = 1.09x -0.65) and spectrofluorometry (r = 0.996; y = 1.10 x + 0.80). The assay of MB activity by the dithiothreitol method was automated, by use of an Abbott Bichromatic Analyser and a Calbiochem Super-Stat Pack Kit. In 60 isoenzyme MB determinations the manual and automated method correlated well (r = 0.990; y = 1.0x -1.36). The simplicity of isoenzyme MB determination by use of dithiothreitol and its ease of automation allow routine monitoring of the isoenzyme activity in patients with ischemic heart disease.

Animals↗
PubMed1971

The effects of intra-aortic counterpulsation on cardiac performance and metabolism in shock associated with acute myocardial infarction.

The effect of intra-aortic counterpulsation (IACP, 22-94 hr) on hemodynamics and cardiac energetics was evaluated in 10 patients in shock after acute myocardial infarction. The data clearly indicate that IACP improves myocardial oxygenation, enhances peripheral perfusion, and probably improves myocardial contractility in the severely diseased heart. Before treatment, decreases in cardiac index (mean value, 1.22 liter/min per m(2)), systolic ejection rate (67 ml/sec), and time-tension index per minute (1280 mm Hg.sec/min) were observed. Systemic vascular resistance varied widely. Low coronary blood flow (68 ml/min per 100 g) was associated with increased myocardial oxygen extraction (79%), low coronary sinus oxygen tension (20 mm Hg), and abnormal myocardial lactate-pyruvate metabolism. During 4-6 hr of IACP, systolic pressure and left ventricular outflow resistance decreased by 18% and 24%, respectively, while cardiac index improved by 38%. Diastolic arterial pressure rose 98%. Increase in coronary blood flow from an average of 68 to 91 ml/100 g per min (P < 0.001) was significantly correlated with rise in mean arterial pressure (r = 0.685). This correlation was best expressed in a third-order curve, which intercepts the point of no flow at a mean aortic pressure of 30 mm Hg. The flow-pressure curve is relatively flat above 65-70 mm Hg, but becomes steeper as mean aortic pressure falls below this point. Myocardial oxygen consumption remained essentially unchanged during early IACP and tended to rise during the later stages. However, the relationship of cardiac work performed to oxygen availability was markedly improved. Myocardial lactate production of 6% shifted to 15% extraction (P < 0.001). After termination of IACP, hemodynamics and myocardial perfusion and metabolism remained improved in the four patients who could be reevaluated. Although the acute shock state was reversed in all patients, only one left the hospital. Extensive myocardial damage limits the long-term survival of such patients. Therefore early IACP seems desirable, when subtle evidence of pump failure after acute myocardial infarction occurs. Early use of IACP may prevent the development of severe coronary shock or may stabilize cardiac energetics in severe shock facilitating subsequent surgical intervention.

Aged↗