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Biomedical subjects

H Walker

Publications and source records attributed to H Walker.

At least 19 recordsLinked to original sources
PubMed1992

Comparison of an EBV transformed cell line and an EBV hybridoma cell line producing the same human anti-HBs monoclonal antibody.

A stable human-mouse heterohybridoma secreting human anti-HBs monoclonal antibody in continuous culture for 12 months was generated. It grew faster than the parent EBV transformed lymphoblastoid cell line (LCL) but produced the same level of specific antibody. The LCL was positive for the Epstein-Barr Virus Nuclear Antigen (EBNA), human CD 23 and contained a diploid number of human chromosomes. The heterohybridoma was negative for EBNA, CD 23 and mouse Ly-1 mouse, despite retaining a full complement of diploid mouse chromosomes and a limited number of human chromosomes.

Animals↗
PubMed1991

Case report 651: Thrombosed, leaking popliteal aneurysm.

A thrombosed, leaking aneurysm of the popliteal artery, mimicking a soft tissue sarcoma both clinically and by MRI examination, is described. It may be difficult to separate a leaking, thrombosed aneurysm from an inflammatory response secondary to a sarcoma with intralesional hemorrhage. An aneurysm should, however, be considered in the differential diagnosis if the mass is present in a well-recognized location for aneurysm and is associated with vascular engulfment and signs of subacute or chronic hemorrhage.

Aneurysm↗
PubMed1991

Congenital spherocytosis, B19 parvovirus infection and inherited interstitial deletion of the short arm of chromosome 8.

We report two siblings with congenital spherocytosis, multiple phenotypic abnormalities and an inherited interstitial deletion of the short arm of chromosome 8 (8p). The propositus came to our attention with acute bone marrow hypoplasia secondary to B19 parvovirus infection. The bone marrow trephine biopsy appearances of intranuclear eosinophilic degeneration in the erythroblasts may be pathognomonic of B19 parvovirus induced acute bone marrow aplasia. The presence of B19 parvovirus DNA was demonstrated in erythroblasts by in situ hybridization. Chromosome analysis of peripheral blood lymphocytes from both siblings showed an interstitial deletion of the short arm of chromosome 8, del (8) (p11p21). This abnormal chromosome was inherited from their mother, who showed this deletion as well as a small fragment representing the deleted 8p chromosome portion, del (8) (p11p21), +f. Centromeric material from chromosome 8 was detected in this chromosome fragment by in situ hybridization using an alpha satellite probe (pJM 128), but not by C banding. Chromosome analysis of skin fibroblasts from the mother and a third sibling with a similar karyotype showed the deleted fragment in over 80% of cells. Cells in which the fragment was absent exhibited the deleted 8p, suggesting there was no mosaicism. The mother and the third sibling were phenotypically normal without spherocytosis. A fourth sibling and the father were normal. The chromosome abnormality was not observed in five of the mother's siblings, suggesting that it arose de novo in the mother. Our findings strongly support a locus for congenital spherocytosis on the short arm of chromosome 8. The frequency of defects at this locus is unknown.

Adolescent↗
PubMed1990

Perioperative and long-term prognostic value of intravenous dipyridamole thallium scintigraphy in patients with peripheral vascular disease.

The prognostic value of long-term risk stratification of patients with peripheral vascular disease who undergo intravenous dipyridamole thallium scintigraphy has not been well studied. We screened 131 patients with peripheral vascular disease who underwent intravenous dipyridamole thallium testing to determine cardiac event rates over an average follow-up of 18 +/- 10 months. Of the 131 patients, 111 subsequently had peripheral vascular surgery. The patients with abnormal thallium scans after dipyridamole had a significantly higher risk of death or myocardial infarction, both in the perioperative phase (7% versus 0%; p less than 0.001) and at late follow-up (17% versus 6%; p less than 0.01). The risk of a cardiac event was two-fold greater when a reversible as compared to a fixed thallium defect was present. Multivariate analysis selected the number of thallium segments with perfusion defects, prior history of angina pectoris, and chest pain during dipyridamole testing as perioperative predictors of a cardiac event. A reversible thallium defect was the only predictor of death or nonfatal myocardial infarction during late follow-up. Thus intravenous dipyridamole thallium scintigraphy is a useful noninvasive test for risk stratification of patients before peripheral vascular surgery and provides prognostic information as to the risk of a cardiac event in the 2-year period after the test. A reversible thallium defect is associated with a significant increased risk and would indicate that coronary angiography should be considered and preoperative coronary revascularization.

Aged↗
PubMed1989

Careers convention.

Explore the source record for details and available documents.

Educational Measurement↗
PubMed1988

Granulocytic sarcoma of the small intestine preceding acute myelomonocytic leukemia with abnormal eosinophils and inv(16).

We report a case of preleukemic granulocytic sarcoma of the small intestine preceding the development of acute myelomonocytic leukemia with abnormal eosinophils and inversion of chromosome 16, inv(16)(p13q22). A literature review suggests that this is a recurring cytogenetic-clinicopathologic association and carries a favorable prognosis, especially if treated aggressively with antileukemic therapy at the time of diagnosis.

Chromosome Inversion↗
PubMed1988

Centroid evaluation in the vernier alignment of random dot clusters.

Clusters of random dots have an advantage over the line elements of a typical vernier acuity task in that their internal light distributions may be easily manipulated without affecting the location of their boundaries. The ability of observers to detect the vertical misalignment of two clusters of random dots was measured over a range of cluster sizes and number of constituent dots. Provided the resultant dot density is high enough to allow interpolation to occur, results demonstrate that the task is performed by analysing the centroid (centre of gravity) of the clusters along the direction of their offset.

Form Perception↗
PubMed1988

Implementing an integrated clinical information system.

The authors examine the vital role nursing professionals have played in the successful implementation of a sophisticated computer system at a regional medical center in the midwest. From preselection analysis through training and implementation, nurses have assumed primary responsibility for managing the multifaceted adaptation and installation of a comprehensive array of patient care functions. This experience can serve as an invaluable example of the relationship between information management, patient management, cost management, and quality enhancement in the hospital setting.

Computer Systems↗
PubMed1986

The significance of host haemopoietic cells detected by cytogenetic analysis of bone marrow from recipients of bone marrow transplants.

Bone marrow from 39 patients who received a bone marrow transplant (BMT) from a matched donor of different sex were studied by chromosome analysis for evidence of mixed haemopoietic chimaerism (MC). Recipient metaphases were detected in the bone marrow of 10 patients after BMT. Patients in whom MC was detected within 6 weeks of BMT did not all have a poor outcome. Two of seven are disease-free survivors at greater than 470 and greater than 632 d. All three patients in whom MC was diagnosed more than 6 weeks after BMT subsequently relapsed. Four factors appear to be important in determining the probability of relapse when MC is detected in a patient after BMT: the timing of detection of residual recipient cells; the proportion of these cells in the bone marrow; persistence of these cells in increasing proportions; and the karyotype of the recipient metaphases detected. Cytogenetic assessment may provide the earliest indication of relapse in these patients. In addition, this study provides further evidence that cyclophosphamide and total body irradiation, as used in these patients, may be inadequate conditioning therapy for BMT.

Adolescent↗
PubMed1979

Effects of hyperthermia on the mouse testis and its response to X-rays, as assayed by weight loss.

The effects of both hyperthermia alone and X-rays combined with hyperthermia on mouse testis have been investigated. Testis weight on heating time was observed for temperatures in the range 39.5 to 43.75 degrees C. The relationship between the reaction rate and the reciprocal of absolute temperature indicated that, over the temperature range considered, the activation energy associated with such thermal damage was (646 +/- 45) x 10(3) J mol-1. No evidence was obtained to indicate a change in slope of the Arrhenius plot over this temperature range. Finally, despite the high sensitivity of the testis to heat and X-rays, no thermal enhancement of the weight loss after irradiation was observed when thermal treatments which, if given alone would produce some observable damage, were administered immediately after irradiation.

Animals↗
PubMed1979

Clonal identification in acute lymphoblastic leukemia.

In a case of acute lymphoblastic leukemia, two distinct types of leukemia blast cells could be identified throughout the course of the disease. The initially dominant type of blast cell was sensitive to chemotherapy; the other was drug-resistant, gradually becoming dominant as the disease progressed. The cell types could be clearly separated by their morphologic and surface membrane marker characteristics. The same chromosomal constitution was present in both types of blast cells, indicating a common clonal origin. Additional chromosomal abnormalities were present in the later stages of the disease, demonstrating that a distinct subclone had proliferated. This study illustrates that in some cases of acute leukemia, disease relapse is caused by growth of drug-resistant subclones that may be clearly identified by changes in morphology and surface membrane marker characteristics.

Adult↗
PubMed1978

Myocardial function in hypothyroidism. Relation to disease severity and response to treatment.

Systolic time intervals (ST) were used to evaluate myocardial function prospectively in 29 hypothyroid patients. The patients were divided into three categories of disease severity: (1) severe hypothyroidism, (2) mild hypothyroidism, and (3) decreased thyroid reserve or "prehypothyroidism." Groups 1 and 2 showed decreased myocardial contractility with a prolonged preejection period (PEP), shortened left ventricular ejection time (LVET), and increase PEP/LVET, compared with normal controls. The STI were more abnormal (P less than .05) in group 1 than in group 2, suggesting that the severity of myocardial dysfunction correlates with the severity of the hypothyroidism. Group 3 had normal STI. Ten patients were restudied when euthyroid and showed complete normalization of their STI, supporting the thesis that hypothyroidism was the sole cause of the initial myocardial dysfunction.

Female↗