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Biomedical subjects

H C Miller

Publications and source records attributed to H C Miller.

At least 55 records · Page 3Linked to original sources
PubMed1987

2,8-Dihydroxyadenine urolithiasis: report of an adult case in the United States.

2,8-Dihydroxyadeninuria is a rare purine metabolic disorder that has been reported to have caused urolithiasis in 14 cases, mostly children. Excretion of the hydroxylated metabolites of adenine results from a deficiency of adenine phosphoribosyltransferase. The insoluble calculi have a similar chemical structure to uric acid and frequently are misdiagnosed as uric acid calculi. Management differs from that of uric acid urolithiasis. We report on an adult with 2,8-dihydroxyadenine urolithiasis in the United States.

Adenine↗
PubMed1987

Severe pulmonary hypertension and multiple left coronary arterial fistulas in association with congenital hepatic fibrosis.

Multiple fistulous communications between the left anterior descending coronary artery and the left ventricle were found in a 55 year old woman with congenital hepatic fibrosis presenting with breathlessness. At cardiac catheterisation severe pulmonary hypertension was also found. In view of the persistent hypoprothrombinaemia, severe thrombocytopenia, and the multiple fistulas the risk of operation was thought to be unacceptable and she continues on medical treatment.

Coronary Vessel Anomalies↗
PubMed1987

A screening sequence for vasculogenic impotence.

Delineation of neural, arterial, and venous components contributing to penile erectile failure is critical to proper patient selection for surgical interventions, particularly for a subset of men with impotence as the sole manifestation of pelvic arterial disease. In addition to obtaining a history and physical examination specific for disordered erectile function and vascular risk factors, we developed a sequence of testing to include noninvasive estimates of penile perfusion, pulse volume recording (PVR), and penile/brachial blood pressure indices (PBPI); somatosensory evoked potentials from dorsal penile (PEP) and posterior tibial nerve stimulation (SEP) and bulbocavernosus reflex time (BCR); stimulation of artificial erection with injection of papaverine (AE); and selective hypogastric-pudendal arteriography with patients under epidural anesthesia, and corpus cavernosography with AE. Three hundred fifty-three men complaining of impotence were screened by PVR and PBPI; among these 42 impotent men and 20 additional concurrent potent control subjects had evoked potentials and BCR measurements, and 55 men received one or more AE injections. On the basis of these results, angiographic investigation was recommended. Age and risk factors were similar in the two groups. Abnormal penile blood perfusion was associated significantly only with cigarette smoking (p less than 0.0001) or overt large vessel disease. Impotent men with (138) or without perfusion abnormalities (215) averaged 54 and 56 years of age, respectively; impotent men with normal flow patterns most commonly had treated hypertension or diabetes (79 of 215 men). Covert neurologic abnormalities were detected in 28 of 42 impotent men. Abnormal penile perfusion plus failure of AE predicted isolated ischiopudendal trunk or pudendal artery disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

A prospective evaluation of the Björk-Shiley, Hancock, and Carpentier-Edwards heart valve prostheses.

From 1975 to 1979, 540 patients undergoing valve replacement were entered into a randomized trial and received either a Björk-Shiley (273 patients) or a porcine heterograft prosthesis (initially a Hancock valve [107 patients] and later a Carpentier-Edwards prosthesis [160 patients]). Two hundred and sixty-two patients required mitral valve replacement, 210 required aortic valve replacement, 60 required mitral and aortic valve replacement, and eight also required associated tricuspid valve replacement (six mitral valve replacement; two mitral plus aortic valve replacement). Analysis of 34 preoperative and operative variables showed the treatment groups to be well randomized. In-hospital mortality was not significantly different among patients receiving the three prostheses for aortic valve replacement (7.6% overall) and mitral plus aortic valve replacement (10% overall), but there was a higher in-hospital mortality for patients undergoing mitral valve replacement with the Carpentier-Edwards prosthesis (15.5% compared with 8.8% overall; p = .03). This difference could not be explained on the basis of any preoperative or operative variable. Median follow-up was 5.6 (range 2.8 to 8.3) years. Actuarial survival after mitral valve replacement was 56.7 +/- 7.0% at 7 years, that after aortic valve replacement was 69.6 +/- 9.6% at 7 years, and that after mitral plus aortic valve replacement was 62.5 +/- 20.0% at 7 years. There was no significant difference in actuarial survival of patients receiving the three prostheses within the mitral, aortic, and mitral plus aortic valve replacement groups, nor was there a difference when these groups were amalgamated. Thirty-seven patients required reoperation for valve failure (15 with Björk-Shiley, 12 with Hancock, and 10 with Carpentier-Edwards valves; p = NS) and 11 died at reoperation (four with Björk-Shiley, four with Hancock, and three with Carpentier-Edwards valves; overall operative mortality 29.7%). Up to 7 years after surgery, there was no significant difference in the incidence of thromboembolism in patients with different prostheses undergoing mitral or aortic valve replacement. There were too few patients undergoing mitral plus aortic valve replacement for meaningful comparison. There was no significant beneficial effect of anticoagulants in patients undergoing mitral or aortic valve replacement with porcine prostheses, but patients were not randomly allocated to anticoagulant treatment. All patients with Björk-Shiley prostheses received anticoagulants.(ABSTRACT TRUNCATED AT 400 WORDS)

Aged↗
PubMed1985

Associations between unfavorable outcomes in successive pregnancies.

Spontaneous abortions in preceding pregnancies were associated with a significantly increased risk of preterm births (less than 37 weeks) and intrauterine growth retardation in the index pregnancies that followed next, even when the effects of risk factors for the index pregnancy were controlled. The predictive effect of the earlier spontaneous abortion was independent of the effect of the risk factors, even though the latter's effect was over twice as great as indicated by odds ratios. The most serious types of severe intrauterine growth retardation occurred more frequently in high-risk than in low-risk pregnancies. Among mothers whose previous pregnancy resulted in low birth weight, the current pregnancy almost always had one or more risk factors.

Abortion, Spontaneous↗
PubMed1985

Prenatal factors affecting intrauterine growth retardation.

Intrauterine growth retardation (IUGR), like postnatal growth retardation, involves skeletal and soft tissues. It is important to distinguish between depletion of soft tissues and stunting of linear skeletal growth, not only in older infants and children, but also in newborn infants. There are three main types of IUGR. To diagnose all three types involves much more than simply obtaining an individual's weight in relation to his or her age, as is now the widely accepted practice in newborn infants. Standards of intrauterine growth should not include growth-retarded newborn infants, insofar as it is possible to exclude them. Tables and graphs of intrauterine growth based on representative populations of newborn infants are apt to be a mixture of unknown numbers of normally grown and growth-retarded fetuses. The suggestion is put forward that standards of intrauterine growth should be based on newborn infants who have not been subjected to known growth-retarding influences prenatally. The diagnosis of intrauterine growth retardation prenatally by ultrasonic techniques has not reached the degree of reliability and validity that is needed for the routine detection of all fetuses with severe intrauterine growth retardation. Prenatal measurements made by ultrasound still require confirmation postnatally by appropriate measurements of infants at birth. The epidemiology, diagnosis, and postnatal courses of newborn infants with severe types of IUGR are discussed.

Child↗
PubMed1984

Interaction of gangliosides with B cells in splenic fragment cultures.

The effect of gangliosides upon murine adult B cells at the single precursor cell level was examined using the splenic focus assay. Adult B cells were stimulated in in vitro organ fragment culture by a hapten-modified carrier protein in the presence of an excess of carrier-primed T cells. The addition of a potential tolerogen in the form of antigen coupled to a carrier not previously presented to the T cells resulted in a temporary unresponsiveness of the onset of antibody production in adult B cells, but not a permanent state of tolerance. This delay could be eliminated by the addition of purified murine gangliosides during the presentation of the hapten coupled to the unrecognized carrier. The ganglioside preparation was fractionated by ion-exchange chromatography and the active fraction was found to be a disialoganglioside. These results suggest that the ganglioside may interfere with membrane receptor-related events occurring during or after antigen binding or cross-linking to responding B cells.

Animals↗
PubMed1984

Effect of afterload reduction in patients with ventricular and physiological pacing.

The effect of afterload reduction was studied in a group of patients who remained breathless or tired after permanent ventricular pacing. Haemodynamic measurements were made before and after giving hydralazine 20 mg intravenously using a triple lumen thermodilution catheter and cuff blood pressure recordings during ventricular pacing at the standard rate of 71/min or an increased rate of 88/min and physiological pacing. Increasing the ventricular pacing rate had no effect on cardiac output as stroke volume fell. Hydralazine produced a greater rise in cardiac output than physiological pacing alone, although peak values were obtained by combining the two. Ventricular pacing produced intermittent large left and right atrial pressure peaks. Physiological pacing produced no such peaks, and mean right and left atrial pressures fell. Hydralazine did not significantly alter atrial pressures. These findings show that in these patients, most of whom had a low cardiac output, afterload reduction with ventricular pacing increased resting cardiac output more than physiological pacing alone. Nevertheless, persistence of high filling pressures despite afterload reduction may limit the potential therapeutic benefit. Care should be taken in extrapolating these data to other patient groups.

Adult↗
PubMed1984

Myocardial infarction related to coronary artery bypass graft surgery.

Fifty consecutive patients undergoing coronary artery bypass grafting for chronic stable angina were assessed by serial electrocardiography, preoperative and postoperative myocardial scanning with technetium-99m pyrophosphate, gated radionuclide ventriculography, and serial measurement of creatine kinase, aspartate aminotransferase, urea stable lactic dehydrogenase, and creatine kinase isoenzyme (MB) to assess the incidence of perioperative myocardial infarction and identify the most appropriate diagnostic techniques. The correlation between myocardial scanning and the measurement of peak enzyme and isoenzyme activity was excellent in the diagnosis of perioperative infarction, although electrocardiography proved less helpful. There appeared to be no advantage in measuring creatine kinase MB rather than the more routinely measured enzymes. There were two deaths and evidence of myocardial infarction in five other patients, an incidence of 14%. Perioperative infarction was associated with a significant reduction in resting ejection fraction in two cases. In those patients without evidence of perioperative infarction the mean increase in ejection fraction of 7.8% was statistically significant.

Adult↗
PubMed1984

Myocardial infarction related to valve replacement surgery.

Fifty consecutive patients, 25 undergoing aortic valve replacement and 25 mitral valve replacement, were studied by serial electrocardiography, preoperative and postoperative technetium-99m pyrophosphate radionuclide scanning, and serial measurement of enzymes (creatine kinase, aspartate aminotransferase, urea stable lactic dehydrogenase) and the MB isoenzyme of creatine kinase to define the incidence of preoperative myocardial infarction and to identify the most appropriate diagnostic techniques. The use of myocardial scanning and measurement of peak enzyme activity proved to be accurate indicators of myocardial infarction, but the electrocardiogram was of limited value. The measurement of creatine kinase MB isoenzyme had no diagnostic advantage over that of the other enzymes. There were two deaths in the series, one due to acute pancreatitis after aortic valve replacement and the other due to myocardial injury after mitral valve replacement. There were four non-fatal myocardial infarctions after aortic valve replacement, giving an incidence of 16%, and none after mitral valve replacement, giving an incidence of 4%.

Adolescent↗
PubMed1983

A model for studying the pathogenesis and incidence of low-birth-weight infants.

A model is proposed for analyzing the many extextrinsic and intrinsic factors that might affect the incidence of low-birth-weight (LBW) infants (less than 2,501 g) adversely in populations of variable socioeconomic status (SES). The model provides for categorizing all mothers either into one of four broad categories of rinsic factors or into a normal group, free of all extrinsic factors. Application of the model in a prospective study of 972 infants showed that the incidence of LBW infants was low in normal pregnancies and significantly higher in the categories of extrinsic factors, that SES had a limited role in the birth of LBW infants, and that intrinsic factors had an almost negligible adverse effect if properly controlled.

Adolescent↗