Search PubMed⌕ Search

Biomedical subjects

W T Miller

Publications and source records attributed to W T Miller.

At least 145 records · Page 8Linked to original sources
PubMed1988

Pulmonary hypertension complicating portal hypertension: findings on chest radiographs.

Pulmonary hypertension is a rare but well-established complication of portal hypertension with a prevalence of 0.73% in one large autopsy series. In this report, we review the findings on chest radiographs in eight patients with this complication. Portal hypertension in these patients was evidenced by the presence of esophageal varices and/or ascites. The causes of portal hypertension were liver cirrhosis in seven patients and portal venous thrombosis in one patient. Pulmonary hypertension was established by right heart catheterization and pressure measurement. Qualitative assessment of the radiographs showed that four patients had the classic findings of pulmonary hypertension including prominent central pulmonary arteries and right ventricular enlargement, three had subtle abnormalities, and one had only cardiomegaly. Measurements of the width of the right descending pulmonary artery and the pulmonary lobar diameter/transverse thoracic diameter ratio were made in five of the patients in whom postero-anterior radiographs were available. The results confirmed our qualitative analysis, although they did not establish the diagnosis in borderline cases. We also observed that pulmonary vascular redistribution to the upper lobes was present in four patients, a finding that has been reported in patients with other causes of pulmonary hypertension. We conclude that the possibility of pulmonary hypertension should be raised in patients with portal hypertension, even when only subtle chest radiographic findings are present to suggest that diagnosis.

Adolescent↗
PubMed1987

Role of enzyme-peptide substrate backbone hydrogen bonding in determining protein kinase substrate specificities.

As part of a search for peptides that have specificity for selected protein kinases, the possibility that adenosine cyclic 3',5'-phosphate dependent protein kinase (A-kinase) recognizes the hydrogen-bonding potential of its peptide substrates was investigated. A-Kinase catalyzes the phosphorylation of five N alpha-methylated and four depsipeptide derivatives of Leu-Arg-Arg-Ala-Ser-Leu-Gly (peptide 1) at rates that differ by at least 7 orders of magnitude. These peptide 1 analogues each lack the ability to donate a hydrogen bond at selected positions in the peptide chain. If a particular amide hydrogen of a peptide amide is involved in hydrogen bonding, which is important for enzyme recognition, the prediction is that peptides which contain an ester or a N-methylated bond at that position in peptide 1 will be comparatively poor substrates. In contrast, if a depsipeptide has a reactivity comparable to that of peptide 1 but the analogous N-methylated peptide has a poor reactivity with A-kinase, the result might indicate that the N-methyl group causes unfavorable steric effects. The depsipeptide that lacks a Leu6 amide proton is a good substrate for A-kinase, but the corresponding N-methylated peptide is phosphorylated far less efficiently. This result and others presented in this paper suggest that although enzyme-substrate hydrogen bonding may play some role in A-kinase catalysis of phosphoryl group transfer, other explanations are necessary to account for the relative reactivities of N alpha-methylated and depsi-containing peptide 1 analogues.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1987

Conformation of Leu-Arg-Arg-Ala-Ser-Leu-Gly bound in the active site of adenosine cyclic 3',5'-phosphate dependent protein kinase.

Studies utilizing NMR spectroscopy have shown that adenosine cyclic 3',5'-phosphate dependent protein kinase (A-kinase) probably binds Leu-Arg-Arg-Ala-Ser-Leu-Gly (peptide 1) in one of two extended coil conformations (A or B). The relative reactivities of a series of N-methylated peptides based on the structure of peptide 1 might, therefore, be related to how well each can assume the A or B conformation. From estimates of the magnitude of steric interactions that would be induced by N-methylation of an amide in peptide 1 that is locked in either conformation, the ability of each peptide to form that conformation was predicted. The ability of A-kinase to catalyze phosphorylation of the N-methylated peptides correlated well with the ability of each peptide to form conformation A, but not conformation B. In accord with these findings, the reactivity of an unreactive N-methylated peptide was partially restored by a second change, which allowed the peptide to assume conformation A. These results suggest that, when bound in the enzymatic active site, peptide 1 has a conformation that resembles structure A much more closely than structure B.

Amino Acid Sequence↗
PubMed1987

Paraspinal lipomatosis: a benign mass.

Paraspinal lipomatosis usually occurs in patients with steroid excess. In two patients a paraspinal mass was detected on conventional radiographs and was subsequently shown to represent benign fat deposition on computed tomography, thereby obviating further studies. Neither patient had been receiving steroids. Paraspinal lipomatosis may be the cause of a benign mass and may be considered in the differential diagnosis of this finding.

Aged↗
PubMed1987

Chronic beryllium disease: diagnosis, radiographic findings, and correlation with pulmonary function tests.

Patients with suspected chronic beryllium disease underwent bronchoscopy and bronchoalveolar lavage. Their bronchoalveolar lymphocytes were incubated with beryllium salts, and quantitative lymphocyte transformation was measured. Seventeen patients with a positive lymphocyte proliferation test were evaluated radiographically with the International Labour Office classification. The most common radiographic abnormalities included diffuse small round and reticular opacities. Hilar adenopathy, linear scars, lung distortion, bullae, and pleural thickening were found less commonly. Specific radiographic findings were compared with pulmonary function abnormalities. The extent of radiographic profusion of small opacities and the presence of linear scars did not correlate with pulmonary function abnormalities. There was, however, a significant correlation between extensive pleural disease and reduced vital capacity in this small group of patients.

Adult↗
PubMed1987

Congestive cardiomyopathy in association with AIDS.

During a 10-month period in 1985 and 1986, three cases of acquired immunodeficiency syndrome (AIDS) and a rapidly progressive fatal cardiomyopathy were encountered. All three patients originally presented with common opportunistic infections and later experienced marked congestive heart failure associated with echocardiographic and radiologic findings consistent with four-chamber cardiomyopathy. Diffuse cardiomyopathy was confirmed postmortem, but in each case a specific cause was not found.

Acquired Immunodeficiency Syndrome↗
PubMed1987

Digital chest imaging: comparison of two film image digitizers with a classification task.

A classification test was used to compare the results of digitizing chest radiographs with a linear diode array camera and a laser scanner. The ability of B readers to classify a pneumoconiosis test set from original radiographs and the digitized images was compared. The classification of profusion was impaired when images were digitized with the diode array camera but not when they were digitized with the laser scanner. The impairment found with images digitized with the linear diode array camera was overcome with use of a zoom function at the display station. The size of areas of opacification was overestimated on images from both scanners. Variation between and within observers (kappa approximately equal to 0.6) was consistent over observers and over modalities.

Evaluation Studies as Topic↗
PubMed1987

Tuberculous pleural effusions.

While a number of recent reports have documented the changing clinical and radiographic spectrum of parenchymal tuberculosis, relatively little attention has been paid to changes in the patterns of pleural tuberculosis. We therefore reviewed the clinical, laboratory, and radiographic characteristics of 26 adult patients with tuberculous pleural effusions. We found that pleural tuberculosis has become a disease of older adults (median age, 56 years) and that 19 percent (5/26) of the cases were due to postprimary (reactivation) disease. This shift in age led to problems in diagnosis, since many of these older patients had underlying or coexisting disease that could have caused a pleural effusion. Both specimens of pleural fluid and pleural biopsy were useful in establishing the diagnosis. Examination of sputum was less helpful. All patients who were not anergic had positive cutaneous reactions to first-strength purified protein derivative of tuberculin. Lymphocytosis of the pleural fluid was not a uniform finding; only 62 percent of our patients had greater than 50 percent lymphocytes on their initial examinations of pleural fluid, and four patients had greater than 90 percent polymorphonuclear cells. All of the effusions were exudates, and four had glucose levels in the pleural fluid that were less than 30 mg/dl. Pleural tuberculosis is an important diagnostic consideration in adult or elderly patients with exudative pleural effusions.

Adult↗
PubMed1986

Recurrence-free survival time for surgically treated soft tissue sarcoma patients. Multivariate analysis of five prognostic factors.

A staging system, based upon the experience of 1215 patients, was published by the American Joint Committee Task Force on Soft Tissue Sarcoma in 1977. A subset of these patients, 594, was selected to study recurrence-free survival time. The authors found 331 patients with a recurrence within 5 years (100 local only, 123 metastatic only, and 108 local + metastatic); median months to recurrence was 9.7. Within 5 years, recurrence was clearly associated with mortality: among the 331 patients who experienced a recurrence, 245 died, whereas only 31 died among the 263 who had no recurrence. To further evaluate the utility of the published staging system, a multivariate analysis of five factors was carried out for 297 of the 594 patients (patients with unknown information for any one of these factors were excluded). Factors in addition to grade that exerted a significant influence on recurrence were: direct extension, symptoms, and location of tumor when survival was measured to the first of any recurrence, and tumor size, measuring survival to the first metastatic recurrence. It is therefore recommended that these factors be taken into account in staging this disease. Estimates of probable recurrence-free survival time based upon the multivariate model (Weibull) are also presented.

Analysis of Variance↗
PubMed1986

Nontuberculous mycobacterial infection in AIDS: clinical, pathologic, and radiographic features.

The medical records, radiographs, and pathologic specimens of ten patients with the diagnoses of nontuberculous mycobacterial infection and acquired immunodeficiency syndrome (AIDS) were examined. The radiographic findings of alveolar or nodular infiltrates and adenopathy were relatively nonspecific but in most cases led to bronchoscopic study or open-lung biopsy, which established the diagnosis. Bronchoscopic washings or sputum cultures, which frequently provided the first confirmation of infection, were always followed by positive blood or tissue cultures. In contrast to nontuberculous infection in immunocompetent hosts, disseminated infection was common, with evidence of extrapulmonary involvement in nine patients. On the basis of these findings, we recommend that any AIDS patient with sputum or bronchoscopic washings demonstrating nontuberculous mycobacterial organisms be tentatively classified as having disseminated infection while being evaluated with blood, bone-marrow, stool, and urine cultures, even if the chest radiograph shows no disease.

Acquired Immunodeficiency Syndrome↗
PubMed1986

Value of CT in the preoperative assessment of lung cancer: a survey of thoracic surgeons.

Practicing thoracic surgeons were randomly surveyed to evaluate how computed tomography (CT) has influenced the preoperative evaluation of bronchogenic carcinoma. Thirty-six percent of the 529 respondents routinely requested CT and 62% did so selectively. Approximately 40% indicated that CT provided useful information in most cases. Nearly all surgeons (98.7%) do not rely on the identification of enlarged lymph nodes with CT to spare the patient surgical staging; however, 77.5% are influenced by CT results in their staging procedures. Fifty-seven percent reported that a negative CT study eliminates surgical staging entirely unless the patient has a "coin lesion," in which case 75% are willing to proceed directly to thoracotomy. For surgeons who use CT selectively, an abnormal mediastinal contour on the radiograph was the most frequent radiologic abnormality to prompt CT (85%). Thirty-seven percent are influenced by tumor histology in their decision to request CT. There was little difference in the pattern of CT use between university and community hospital surgeons.

Health Surveys↗
PubMed1986

Active tuberculosis after isoniazid chemoprophylaxis of Southeast Asian refugees.

The outcome of isoniazid chemoprophylaxis for tuberculosis was assessed in refugees from Southeast Asia. From July 1979 through June 1982, 2,795 tuberculin-positive refugees were prescribed isoniazid chemoprophylaxis at the time of their resettlement in King County, Washington. Through December 1983, 19 cases of active tuberculosis had arisen in those refugees. The annual incidence varied between 2.04 and 2.86 cases per 1,000 receiving treatment during the 4 yr after initiation of chemoprophylaxis (cumulative incidence, 9.66 per 1,000). Seven of the cases of tuberculosis occurring after isoniazid chemoprophylaxis were pulmonary, 1 was pulmonary and extrapulmonary (lymphatic), and 11 were extrapulmonary alone (lymphatic, 6 cases; pleural, 4 cases; soft tissue, 1 case). Fifteen of the 19 cases were culture positive, among which 8 M. tuberculosis isolates were susceptible to isoniazid and 7 were resistant. A case-control analysis showed that poor compliance, defined as taking isoniazid for 3 months or less, was associated with a sixfold increase in risk for subsequent isoniazid-susceptible tuberculosis but with no increased risk for subsequent isoniazid-resistant disease. Thus, active tuberculosis continued to occur with a low but relatively constant incidence after prescription of isoniazid chemoprophylaxis to Southeast Asian refugees. In this setting, poor compliance with chemoprophylaxis predisposed to isoniazid-susceptible, but not to isoniazid-resistant tuberculosis. There is a need to improve the approach to prevention of tuberculosis in Southeast Asian refugees.

Adolescent↗
PubMed1985

Normal variations in body surface electrocardiographic potential distributions during QRS: effects of exercise and exercise training.

Total body surface electrocardiographic potential distributions, oxygen uptake (VO2), blood pressure and heart rate were monitored during maximal exercise procedures performed by 26 normal adult subjects (male and female) covering a range from sedentary to fit. Normal variations in the exercise response of the ECG during QRS were found not to be related to variations in the level of cardiovascular fitness as quantified by maximal VO2 or to variations in maximal heart rate and blood pressure. In a second experiment, seven sedentary adult female subjects underwent an exercise training protocol for ten weeks. Maximal exercise tests were performed before and after the training period. Exercise-induced changes in the ECG during QRS were not affected by the physical training. We conclude that normal variations in the exercise response of the ECG during QRS are not related to the level of cardiovascular fitness of the subject.

Adolescent↗