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Biomedical subjects

D W Taylor

Publications and source records attributed to D W Taylor.

At least 163 records · Page 9Linked to original sources
PubMed1982

Process versus outcome in hypertension: a positive result.

We studied the association between the outcome of antihypertensive care and three items of that care among 230 hypertensive steelworkers who were referred to 83 physicians. The first item was the decision to treat some patients but not others: 63% of the patients were prescribed antihypertensive drugs and the mean decrease in their diastolic blood pressure (DBP) was greater than that among untreated patients (12.2 +/- 0.84 vs 7.8 +/- 0.83 mm Hg [+/- SEM], p less than 0.001). The second item was the vigor of prescribed medication: Patients prescribed more vigorous treatments had lower DBP (p less than 0.005). Third, patient compliance was related to achieving a goal DBP of less than 90 mm Hg (p less than 0.05) and the product of prescribed vigor and compliance was highly associated with DBP response (p less than 0.0001). These results stand in contrast to those of previous studies that failed to detect associations between various other items of the care process and the outcome of antihypertensive care.

Adult↗
PubMed1981

Monoclonal antibodies to stage-specific, species-specific, and cross-reactive antigens of the rodent malarial parasite, Plasmodium yoelii.

Eighteen hybridoma cell lines were used to study species-specific, stage-specific, and serological cross-reactive antigens of the rodent malarial parasite, Plasmodium yoelii. Specificity and location of plasmodial antigens were determined by indirect fluorescent-antibody analysis. Results showed that a minimum of 12 distinct plasmodial antigens could be distinguished by the 18 hybridomas. Antigens were found on the surface or within the cytoplasm of the parasite, but not on the surface of erythrocytes from infected animals. The majority (11 of 12) of antigens were present in all erythrocytic stages of the parasite, but one was stage-specific for merozoites. Additional studies showed that 6 of 18 of the monoclonal antibodies identified species-specific antigens, 2 of 18 recognized antigens confined to related rodent malarial parasites (Plasmodium berghei, Plasmodium vinckei, and Plasmodium chabaudi), whereas 8 of 18 detected cross-reactive antigens common to rodent, primate (Plasmodium knowlesi, Plasmodium falciparum), and avian (Plasmodium gallinaceum) malarias.

Animals↗
PubMed1981

Clinical validity of a negative venogram in patients with clinically suspected venous thrombosis.

Although it is generally accepted that negative venography excludes deep vein thrombosis (DVT) in patients in whom it is clinically suspected, there is no evidence to support this conclusion. To test the correctness of withholding anticoagulant therapy in these patients, we followed 160 consecutive patients who had clinically suspected DVT and negative venograms to determine the frequency of postvenographic DVT. Anticoagulant therapy was withheld in all patients. No patient died or developed pulmonary embolism during 3 months of follow-up. Two of the 160 patients (1.3%) attended the clinic on an emergency basis during follow-up with new symptoms of DVT and in both patients, DVT was confirmed by objective testing. These events developed within 5 days of venography, which suggests that they were induced by venography. Nevertheless, the findings indicate it is safe to withhold treatment in patients with clinically suspected DVT and negative venograms.

Adolescent↗
PubMed1981

Replacement of venography in suspected venous thrombosis by impedance plethysmography and 125I-fibrinogen leg scanning: a less invasive approach.

Noninvasive diagnostic testing is gaining acceptance in the evaluation of patients with clinically suspected venous thrombosis. Although clinically useful, all these tests have limitations, and the safety of basing therapeutic decisions on their outcome has not been assessed. We have done a prospective study of 322 symptomatic patients to ascertain the safety of replacing venography with impedance plethysmography and leg scanning. To provide a diagnostic reference, we did venography in all patients but withheld anticoagulants if the noninvasive tests were negative irrespective of the results of venography. None of the 163 patients with negative noninvasive tests died or developed clinical pulmonary embolism during 3 months' follow-up, confirming the safety of this approach. In two, clinically evident postvenographic venous thrombosis developed, confirmed by repetition of these objective tests. Also, the positive predictive values indicate that therapeutic decisions can be based on a positive noninvasive outcome in patients without clinical disorders known to produce false-positive results.

Adolescent↗
PubMed1980

Randomized trial of therapy with platelet antiaggregants for threatened stroke. 2: Observations on the pathogenesis and natural history of threatened stroke.

Transient cerebral ischemia and stroke may occur despite previous occlusion of the artery supplying the appropriate part of the brain. After occlusion of the internal carotid artery, emboli may pass from the "stump" of the occluded artery to later produce transient cerebral ischemia or a stroke. Transient cerebral ischemia and stroke are due to a variety of conditions, some of which are strongly correlated with platelet thromboembolism, while others have little primary relation to thrombosis. The impact of this on therapeutic considerations is obvious. Thromboembolism related to myxomatous degeneration of the mitral valve (mitral valve prolapse) is a factor to consider in determining the cause of a stroke in a younger person. The prognosis for the different varieties of threatened stroke is incompletely known. When due to arteriosclerosis of the large cerebral arteries, transient cerebral ischemia and minor strokes pose a cumulative threat for a major stroke or death of 13% in the first year, 22% in the second year and 30% in the third year.

Adolescent↗
PubMed1980

Further evidence relating mitral-valve prolapse to cerebral ischemic events.

Echocardiography demonstrates prolapse of the mitral valve in at least 5 per cent of the population. Since some observations have linked this condition to stroke, we studied its incidence in two groups of patients with cerebral ischemia. The older group contained 141 patients over 45 years of age (mean, 64.7 years) who had transient ischemia or partial stroke. Prolapse was found in eight (5.7 per cent) of these patients and in 10 (7.1 per cent) of 141 age-matched controls. The second group contained 60 patients who had transient ischemia or partial stroke and were under 45 years old (mean 33.9 years). Prolapse was detected in 24 patients (40 per cent) but in only five (6.8 per cent) of 60 age-matched controls (mean age, 33.7 years). The odds ratio, 9.33, was highly significant (P less than 0.001). In six of the 24 patients there were other potential causes for cerebral ischemia leaving 18 whom the only recognizable potential cause was a prolapsing mitral valve (odds ratio, 7.00; P less than 0.001). This study suggests that this entity has a role in cerebral ischemia, at least in younger patients. (N Engl J Med 302:139-144, 1980).

Adult↗
PubMed1980

Alterations in the distribution and proliferative responses of rhesus monkey peripheral blood and spleen cells during malaria (Plasmodium knowlesi) infection.

Rhesus monkeys are used frequently as animal models in malaria research, but few studies have evaluated lymphocyte functions in these animals after experimental infections with the primate malarial parasite Plasmodium knowlesi. In this study, the distribution and mitogen responses of mononuclear cells in the peripheral blood and spleens of 16 P. knowlesi-infected rhesus monkeys were followed. All animals included in the study developed acute infections and were bled out with parasitemias of more than 50%. With progression of the infection, alterations in the peripheral blood mononuclear cells were observed, including decreases in the percentage of T cells (measured by E rosette formation) and the total numbers of E and EAC rosette-forming cells per cubic millimeter. In addition, peripheral blood mononuclear cells displayed reduced responses to mitogen stimulation with phytohemagglutinin, concanavalin A, and pokeweed mitogen. Peripheral blood mononuclear cells from infected animals showed similar reductions in mitogen responses when cultured in media containing 15% autologous pre- or postinfection plasma. The mitogen responses of spleen cells did not appear to be affected, but a significant reduction in the proportion of splenic T cells was observed. These lymphocyte changes in P. knowlesi-infected rhesus monkeys are similar to those reported for mice with acute rodent malaria and for humans with chronic Plasmodium falciparum infections.

Animals↗
PubMed1980

A comparative study of rosette formation in 12 species of nonhuman primates.

Lymphocytes, isolated from the peripheral blood of 12 species of nonhuman primates, were tested for the ability to form rosettes with antibody-complement-coated erythrocytes (EAC rosettes) and with erythrocytes from various animal species. In general, New World primates (wooly, spider colobus, capuchin and owl monkeys) had a greater number of EAC rosette-forming cells (30-44%) than did Old World monkeys (baboons, gibbons, rhesus, cynomolgus, pigtailed, stumptailed and Japanese macaques) (22-30%). All possessed lymphocytes capable of forming rosettes with sheep erythrocytes. Lymphocytes from some primate species formed rosettes with canine, equine, goat or porcine erythrocytes.

Animals↗
PubMed1980

Differentiating owl monkey T and B lymphocytes by rosette formation.

Subpopulations of Aotus trivirgatus lymphocytes can be differentiated by the technique of rosette formation. Owl monkey B cells can be identified by erythrocyte-antibody-complement (EAC) rosette formation, since over 90% of EAC rosette-forming cells (RFC) have detectable surface immunoglobulins. A separate population of Aotus lymphocytes forms rosettes directly with sheep erythrocytes (E rosettes) and appears to be thymus-dependent (T cells) because (1) E rosette formation is blocked by anti-thymus serum, (2) over 80% of owl monkey thymocytes form E rosettes, and (3) most E RFC lack detectable surface immunoglobulins.

Animals↗
PubMed1980

A randomized trial of aspirin and sulfinpyrazone in patients with threatened stroke. Results and methodologic issues.

In the Canadian Cooperative Study of aspirin and sulfinpyrazone in patients with threatened stroke, there was no demonstrable benefit of sulfinpyrazone but there was a significant overall risk reduction in stroke or death of 31% with aspirin (p less than 0.05). This benefit of aspirin was restricted to males, in whom the risk reduction in stroke or death was 48% (p less than 0.005). As with a large-scale clinical trials, questions have been raised about the methodology of the study, including the type of patient included, the choice of outcome measures, the factorial design and the analysis of subgroups. In this report, the design and principal results of the study are summarized and the above methodologic concerns are discussed.

Actuarial Analysis↗
PubMed1980

Data systems support for a large, long-term carcinogenic (ED01) study.

Data Systems Support for the 24,192 mouse toxicological ED01 study at the National Center for Toxicological Research required technology heretofore not available in the field of Toxicology. The large volume of data expected from this study, multiple studies being conducted simultaneously, and accurate and timely information in a usable timeframe, were problems solved by the data systems personnel. NCTR's Integrated Research Support System was initiated for this study.

Animals↗
PubMed1980

Radioimmunoassay for detecting antibodies against murine malarial parasite antigens: monoclonal antibodies recognizing Plasmodium yoelii antigens.

A solid-phase radioimmunoassay (SPRIA) in microtiter wells was established for detecting antibodies against Plasmodium yoelii Ag. The SPRIA was found 1) to require as little as 5 micrograms of crude parasite Ag per well, 2) to be able to detect 0.5 ng of monoclonal Ab, and 3) to be 10(4) times more sensitive than the indirect fluorescent Ab staining technique. In a modification of the above assay using intact RBC as an Ag, hyperimmune serum showed significant binding to the surface of erythrocytes of mice infected with P. yoelii parasites but not to RBC of normal mice. Hybridomas were prepared by fusing infected mouse spleen cells with P3-NS1/I-Ag4-1 myeloma cells. Using the SPRIA, hybrids secreting Ab against P. yoelii 17XL Ag were detected. All the hybrids detected by SPRIA secreted Ab binding to free parasites but not to the surface membrane Ag on the infected RBC. The number of positive hybrids produced by fusing spleen cells from mice given a double infection (17XNL and 17 XL) was not greater than that produced by freezing spleen cells from mice given a single infection (17 XL).

Animals↗