Search PubMed⌕ Search

Biomedical subjects

R Miller

Publications and source records attributed to R Miller.

At least 667 records · Page 37Linked to original sources
PubMed1986

Dose-response range of encainide for benign and potentially lethal ventricular arrhythmias.

A multicenter, 2-week, double-blind, placebo-controlled, parallel group study was performed to determine the dose-response relation of encainide administered 3 times daily and to determine its onset of action. To be included in the study, patients with benign or potentially lethal ventricular arrhythmias were required to have an average of at least 30 ventricular premature complexes (VPCs) per hour on 48-hour Holter monitoring after a 48-hour washout period without antiarrhythmic drug treatment. Patients were randomly assigned to receive either placebo or 10, 25 or 50 mg of encainide 3 times daily (tid) for 2 weeks. Of the 125 patients who entered the study, 122 were available for efficacy analysis. Efficacy was determined using 24-hour Holter monitoring on days 1, 7 and 14. There was no difference in frequency of VPCs or of ventricular tachycardia events in the placebo and 10-mg-tid encainide arms. At doses of 25 and 50 mg of tid, encainide was effective in suppressing VPCs and in reducing the number of episodes of ventricular tachycardia. A positive dose-response relation was identified. The onset of effect of encainide was apparent at 3 hours and lasted for 24 hours with tid dosing. No difference in on-therapy conditions were found among the 4 study arms. No patients were discontinued from the study because of electrocardiographic changes. There was no statistically significant change in vital signs or physical examination data. In 1 patient an elevated serum glucose level developed. No symptomatic proarrhythmic events occurred and none required discontinuation of study medication.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

Characterization and androgenic regulation of soluble protein kinases and protein phosphorylation in rat ventral prostate gland.

The soluble protein kinase activities for protamine and casein, the histone kinases modulated by cAMP or Ca2+ and phospholipid, as well as the phosphorylation patterns of endogenous proteins were measured in rat ventral prostates from normal adults, castrates, and dihydrotestosterone-treated castrates. In normal prostate, the ratio of cAMP-dependent type I and II kinases was approximately 1:5. After a 3-week period of castration-induced regression, the concentrations of both enzymes were increased, but on a total organ basis, type I was decreased to 56%, while type II was reduced to 20% of normal levels. Casein kinase activity in unfractionated cytosol was not significantly altered by castration but when partially resolved into type I and II enzymes, there appeared to be a selective reduction in the type I component. In contrast, the total organ activities of protamine kinase or Ca2+-activated, phospholipid-dependent kinase, two measures of protein kinase C enzyme, were significantly increased (64 and 71%, respectively) above sham controls in regressed organs of castrates. All of the castration-induced changes in protein kinases were restored toward normal by dihydrotestosterone treatment. Castration effects on protein kinase C and the cAMP-dependent kinases appeared to be manifest in the phosphorylation of endogenous proteins. Castration resulted in a qualitative shift in the cAMP-dependent phosphorylation patterns as measured by gel electrophoresis, with increases in four major bands and decreases in two others, whereas the Ca2+-activated, phospholipid-dependent phosphorylation patterns were all enhanced. It is concluded that the androgenic regulation of protein kinase C differed qualitatively from that of other kinases, and its activation upon withdrawal of the androgenic stimulus may be involved in autophagic mechanisms in the prostate.

Androgens↗
PubMed1986

Giant cell tumor of the infratemporal fossa: report of case.

A rare case of giant cell tumor occupying the infratemporal fossa is reported. The site of origin was obscure, although the tumor had obviously eroded a portion of the zygomatic arch and involved the outer cortex of the temporal bone. Aggressive surgical ablation is suggested as the primary treatment of choice for giant cell tumors in any location. Long-term follow-up evaluation is also necessary.

Cell Nucleus↗
PubMed1986

The syndrome of type A chronic atrophic gastritis, pernicious anemia, and multiple gastric carcinoids.

Gastric carcinoid tumors comprise approximately 1.0 to 2.7% of all carcinoid tumors. There appears to be an association between gastric carcinoids and pernicious anemia on the basis of underlying type A chronic atrophic gastritis. We review the relevant literature and describe a 63-year-old woman who had pernicious anemia and multiple polypoid gastric carcinoid tumors. The association of these disorders, proposed mechanisms of such association, and the need for an aggressive diagnostic approach are discussed.

Anemia, Pernicious↗
PubMed1986

Selection of replacement therapy for patients with severe factor VII deficiency.

The risk of significant bleeding in patients with severe Factor VII (FVII) deficiency is well documented. However, controversy regarding management exists not only for the choice of FVII replacement product, but also for the desired hemostatic level of FVII. Two case reports are presented where fresh frozen plasma (FFP) and several Factor IX (FIX) complex concentrates were used to achieve hemostasis. Significantly higher FVII levels were achieved with Proplex (FIX Complex, Hyland Therapeutics) than with other products. Although this and other reports indicate that minor bleeding can be controlled with levels of FVII under 15%, life-threatening hemorrhages require higher FVII levels that can be attained only by using a product with a significant FVII content. It is important to know the FVII content of FIX concentrates in order to plan appropriate therapy for patients with FVII deficiency.

Blood Coagulation Factors↗
PubMed1986

Effect of L-thyroxine on serum angiotensin converting enzyme activity in sheep.

The effect of L-thyroxine on serum angiotensin converting enzyme activity using a sheep model was examined. Following two weeks of L-thyroxine treatment, the activity of serum angiotensin converting enzyme was increased from 6.92 U/ml to 8.65 U/ml (s.e.m. = 0.40, n = 13, P less than 0.01). Discontinuation of L-thyroxine treatment resulted in lowering the activity of serum angiotensin converting enzyme within three weeks to values close to those observed during the control period. It was concluded that L-thyroxine modulates serum angiotensin converting enzyme activity. The sheep is an appropriate animal model for the study of the factors that control serum angiotensin converting enzyme activity.

Animals↗
PubMed1986

The Montgomery-Asberg Depression Scale: reliability and validity.

The Montgomery-Asberg Depression Scale was evaluated in 44 depressed inpatients. All items of the scale occurred frequently in the sample; the scale exhibited construct validity (internal homogeneity) and concurrent validity relative to the Hamilton Depression Scale and the concepts of endogenous and nonendogenous depression. Sleep disturbance, reduced appetite, and suicidal thoughts, correlated poorly with the remainder of the scale. Reasons for this finding are discussed. Inter-rater reliability was demonstrated between a psychiatrist and a nurse on individual item and total scale scores.

Adult↗
PubMed1986

The influence of oxygen tension on theophylline clearance in the rat isolated perfused liver.

The effect of changes in the rate of perfusion and oxygen tension (PO2) on theophylline clearance was determined in the rat isolated perfused liver. Changes in rate of perfusion had no effect on the extraction ratio of theophylline while a decrease in the PO2 significantly increased the half life of theophylline. These results suggest that changes in PO2 whether due to disease states or oxygen administration may necessitate theophylline dosage adjustment.

Animals↗
PubMed1986

Optimal detection of the progression of coronary artery disease: comparison of methods suitable for risk factor intervention trials.

To assess the best method of quantitating progression of coronary disease, we studied four measurements in 114 coronary segments from 35 medically treated patients from whom angiograms were obtained 5 years apart. Only stenoses of less than 70% that were visualized in nearly identical projections on both angiograms were evaluated. Vessel edges were measured by use of catheter calibration and an automated computer algorithm yielding two "absolute dimensions" (mean and minimum diameters) and two measurements (percent stenosis and atheroma area) that required a "normal reference" diameter. The coefficient of variation for repeated segment measurements was less for mean and minimum diameter than for percent stenosis and area of atheroma. The best measure of progression of coronary disease as determined by t test comparison of different methods was the change in mean diameter over time (6.7 +/- 14.1% decrease), whether calculated on a per coronary segment or per patient basis (p less than .001). Based on this measurement and its standard deviation of progression of coronary disease in this patient subset with relatively benign disease, it is estimated that 470 patients per group would be required for an interventional study to demonstrate a 33% reduction in disease progression (207 patients for 50% reduction) at a 95% confidence level and 90% power.

Cardiac Catheterization↗
PubMed1986

Intensification and habituation of experimental motion sickness in squirrel monkeys by repeated horizontal rotation.

The aim of this research was to quantify the development of habituation or intensification of experimental motion sickness induced in Bolivian squirrel monkeys by repeated exposures to horizontal rotation. Incidence, frequency, and latency of vomiting responses were recorded from monkeys rotated daily in a transparent testing chamber at 30 rpm for periods of 1 or 2 hours. Data showed that more than half of the subjects revealed habituation in terms of increased latencies for vomiting. Some showed a tendency to vomit increasingly earlier with multiple daily exposures to rotation. The development of habituation and intensification was evident as early as the second day of rotation. The number of emetic episodes per day decreased as a consequence of repeated rotation, but intensification of vomiting frequency did not occur beyond the fifth day.

Animals↗
PubMed1986

Filterability of erythrocytes and whole blood in preterm and full-term neonates and adults.

Filtration techniques are widely used to assess red blood cell (RBC) deformability and flow behavior of RBC in microcirculation. In this study filtration rates of RBC from 10 very low birth weight infants (24-30 wk gestation), 10 more mature preterm infants (31-36 wk gestation), 10 full-term neonates, and 10 adults were measured by using Nucleopore filters with pore diameters of 5 micron and filtration pressures of 1, 2, 5, and 10 cm H2O. The major results follow: At each of four filtration pressures, filtration rates of washed RBC were significantly (p less than 0.05) lower in the preterm infants than in the term neonates who in turn showed lower values than adults. The differences among the four groups became less as the pressure was increased from 1 to 10 cm H2O. The filtration rates increased with decreasing MCV (r = -0.86). The filter flow resistance (computed as ratio of filtration pressure and filter flow rate) decreased as the filtration pressure was raised from 1 to 10 cm H2O. The largest drop, 31% (p less than 0.05), was observed in the most immature infants, the smallest, 10% (p greater than 0.05), was seen in adults. At a pressure of 1 cm H2O the calculated mean transit time for RBC through the 5-micron pores was on an average 3.7 times longer in the smallest preterm infants than in the adults (19.7 +/- 7.8 and 5.3 +/- 1.4 ms, respectively), whereas the factor was only 2.7 at a pressure of 10 cm H2O (13 +/- 0.4 and 0.5 +/- 0.1 ms, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

A crossed polaroid-pinhole device.

The study describes the use of a pinhole device in which the light-absorbing area surrounding the holes is varied by polarizing filters. The study demonstrates that a pinhole aperture of 1.6-1.8 mm in diameter with polaroids crossed at 90 degrees will allow a visual acuity equal to or better than 20/40 in the face of refractive errors of 1, 2, and 3 diopters. The study next evaluates the effects of pinholes of different sizes and the polarizing components crossed at angles less than 90 degrees. The study concludes by showing that polaroids crossed at between 75 degrees and 85 degrees allow a greater depth of focus, a larger visual field, and greater illumination than traditional pinhole devices.

Humans↗
PubMed1986

Hepatobiliary pathology in hemodialysis patients: an autopsy study of 78 cases.

Necropsy findings of hepatobiliary system from 78 patients with end-stage renal disease maintained on hemodialysis are reported. Ninety percent of the patients exhibited some abnormalities. Multiple abnormalities often coexisted in each patient. Hepatomegaly was found in 50% of the patients and could be attributed to a discernible cause in all but two of the affected patients who had isolated hepatomegaly. Hepatic congestion was also prevalent and was complicated by fibrosis, cardiac cirrhosis, and centrilobular necrosis and hemorrhage in some patients. This was associated with chronic fluid overload, hypertension, and/or cardiovascular disease in the affected patients indicating the importance of adequate control of these factors. Mild periportal hepatic fibrosis, fatty metamorphosis, triaditis, hemosiderosis, and cystic changes were also seen with some frequency--the latter were associated with polycystic kidney disease and were complicated by massive intracystic hemorrhage and abscess formation, each in one patient. Chronic active hepatitis was found in three patients and was associated with chronic HBs antigenemia in one patient and presumed non-A, non-B infection in two. Nearly 22% of the patients showed either cholelithiasis at autopsy or before cholecystectomy due to complications. Significant negative findings included lack of acute viral hepatitis, silicone hepatosis, and recently described focal anoxic lesions associated with erythrocyte sludging. In conclusion, the present study has demonstrated the spectrum of hepatobiliary pathology in a large group of patients with end-stage renal disease maintained on hemodialysis.

Adult↗
PubMed1986

Orbital-adnexal lymphangiomas. A spectrum of hemodynamically isolated vascular hamartomas.

A retrospective review of 13 cases of lymphangioma has led to a classification of these lesions into categories of superficial, deep, and combined types. The clinical manifestations, prognosis, and management directly correlate with the pathophysiology and the location of the lesions. Superficial lesions consist of isolated multicystic vascular abnormalities of cosmetic significance only. Deep orbital lymphangiomas present as spontaneous, acute proptosis due to retrobulbar hemorrhage. Combined lesions demonstrate both superficial and deep components and are also characterized by spontaneous hemorrhages. Histopathologically, lymphangiomas represent a spectrum of vascular hamartomas with a constellation of features that parallels the clinical progression and histology of similar lesions elsewhere in the head and neck. This may include the presence of diaphanous serous-filled vascular channels, a connective tissue stroma with lymphorrhages, features of old hemorrhage, dysplastic vessels, and random smooth muscle bundles. Both direct and indirect evidence suggests that these lesions are characterized by relative hemodynamic isolation.

Adult↗
PubMed1986

Race difference in susceptibility to noise-induced hearing loss.

Pure-tone audiometric thresholds were compared in 28 black and 28 matched white male Emergency Medical Service firefighters exposed to high levels of ambulance siren noise. Groups were matched on the basis of chronologic age, duration of firefighter employment, and prevalence of nonjob-related noise exposure. Results suggested that whites are more susceptible to the damaging effects of high-level noise than blacks. In both the mid- and high-frequency regions of the audiogram, blacks showed significantly better sensitivity than whites on the poorer ear. On the better ear, the sensitivity difference between blacks and whites widened as employment duration and, therefore, duration of noise exposure, increased.

Adult↗