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Biomedical subjects

H M Clark

Publications and source records attributed to H M Clark.

9 recordsLinked to original sources

Cytogenetic and molecular studies of t(14;18) and t(14;19) in nodal and extranodal B-cell lymphoma.

We have examined 107 cases of B-cell lymphoma for the t(14;18) translocation, characteristically described in follicular lymphoma. B-Cell lymphomas of extranodal origin, and in particular malignancies derived from mucosa-associated lymphoid tissue (MALT), were compared with node-based lymphomas of follicular and diffuse morphology. Cytogenetic techniques were supplemented by molecular analysis using probes which recognize both the major and the minor breakpoint regions of the bcl-2 gene located on chromosome 18 (q21). t(14;18) was detected in 55 per cent of follicular and 27 per cent of diffuse B-cell lymphomas thought to be of follicle centre cell origin. Cytogenetics and molecular analysis proved equally effective in demonstrating the translocation. t(14;18) was not observed in the 36 extranodal lymphomas examined, of which 20 were characterized histologically as lymphomas of MALT, using either technique. In addition, 30 cases demonstrated only a germline band when probed with a bcl-3 probe specific for t(14;19), a translocation observed in chronic lymphocytic leukaemia (CLL). Cytogenetic abnormalities were detected in all cases of extranodal lymphoma, although no consistent abnormality was observed. Numerical abnormalities of chromosomes 3, 6, 16, and 18; structural abnormalities of chromosomes 2, 6, 8, and 9; and small marker chromosomes were frequently seen. This study provides data which suggest that different genetic events are involved in the development of lymphoma of MALT from those giving rise to follicle centre cell lymphomas.

Autoradiography

Isolation of HIV-1 from plasma of infected individuals: an analysis of experimental conditions affecting successful virus propagation.

Experimental conditions affecting the successful propagation of HIV-1 from the plasma of seropositive individuals were examined. It was determined that whole blood samples collected with lithium heparin as the anticoagulant, immediate plasma separation, and immediate culturing were best suited for obtaining viable virus from plasma. Virus was isolated by infecting fresh phytohemagglutinin-stimulated normal donor peripheral blood mononuclear cells (PBMCs) with plasma followed by weekly cocultivation with new target cells. The plasma virus isolation rate was the greatest and HIV-1 titers were the highest for those individuals with less than 200 CD4+ cells/mm3 and decreased as the level of CD4+ cells approached normal values. We were able to obtain positive cultures from 29.5% of those patients with CD4+ counts greater than 500/mm3. HIV-1 titers in plasma also correlated with high serum p24 antigen levels when serum was treated with glycine to dissociate antigen-antibody complexes.

Adult

The effects of interactive video on cognitive achievement and attitude toward learning.

The purpose of this experimentally designed study was to determine the effects of an interactive videodisc program, entitled "Diabetic Health Assessment," versus traditional lecture on cognitive learning and affective behaviors of baccalaureate nursing students. It was hypothesized that: 1) there would be no significant difference in the cognitive achievement scores between those students taught by an interactive videodisc program (experimental group) compared to those students taught by a traditional lecture method (control group), and 2) there would be a statistically significant difference in student attitude toward learning between those students taught by an interactive videodisc program compared to students taught by a traditional lecture method. Eighty-three third-year baccalaureate nursing students at a major urban university served as subjects and were randomly assigned to either a control (n = 41) or an experimental group (n = 42). The multivariate analysis of covariance with two criteria and the pretest as the covariate was significant (p = .000, df = 4, 140) indicating that the adjusted posttest scores on the two measures were significantly different for the experimental group compared to the control group. The univariate F for the cognitive measure was nonsignificant (p = .283, df = 2, 72) indicating that students' achievement under interactive video is not significantly different than under traditional lecture. The univariate F for the affective measure was significant (p = .000, df = 2, 72) indicating that the students learning by interactive video possessed a more positive attitude toward learning than those learning by traditional lecture method of instruction.

Achievement

Analysis of carboxyhemoglobin and cyanide in blood from victims of the Dupont Plaza Hotel fire in Puerto Rico.

Ninety-seven people died from a fire that occurred in the Dupont Plaza Hotel in Puerto Rico on 31 Dec. 1986. All, except four who died later in the hospital, were found dead at the scene. All of the fatalities at the hotel (except for eight) were burned beyond recognition. Blood from seventy-eight of the victims was screened for carboxyhemoglobin at the Institute for Forensic Sciences in Puerto Rico and was then sent to the National Institute of Standards and Technology, Gaithersburg, Maryland, for analysis of carboxyhemoglobin and cyanide concentrations. The blood data indicated that carbon monoxide and hydrogen cyanide, singly or combined, were probably not responsible for the majority of the deaths that occurred in the badly burned victims. On the other hand, the significantly higher carboxyhemoglobin in the nonburned victims indicated that carbon monoxide alone or combined with hydrogen cyanide probably played a major role in the cause of their deaths.

Burns

Reduction and release of ferritin iron by plant phenolics.

The reductive release of ferritin iron by several naturally occurring o-diphenols was studied. The initial rate of iron release was quantified by spectrophotometric measurement of the Fe(ferrozine)3(2+) complex, which absorbs maximally at 562 nm. The initial rate of iron release was dependent upon o-diphenol concentration, but not on the concentration of the chromophoric chelating agent, ferrozine, Stoichiometric measurements resulted in a ratio of 2Fe(II) released per molecule of o-diphenol. The series of o-diphenols studied included, caffeic acid, chlorogenic acid, dihydrocaffeic acid, 3,4-dihydroxybenzoic acid, and several analogs. These reductants represent an oxidation reduction potential range of 0.38 volts. A direct correlation between reducing power of the o-diphenols and rate of ferritin iron release was observed. Superoxide dismutase, catalase, mannitol, or general radical traps had no effect on the rate of iron removal; however, EDTA and oxalate inhibited iron release. A mechanism for ferritin iron reduction and release by o-diphenols consistent with the experimental observations is discussed.

Animals

The linkage that worked: the Catholic University of America/Carroll Manor Teaching Nursing Home Program.

The TNH at the CUA/CM site included a group of people who agreed to direct their mutual commitment to common goals; they operated within a shared belief system, agreed to model a liaison that would result in quality care for the elderly, and hoped to create interest in gerontological nursing by increasing the number of prepared gerontological nursing specialists. Four areas of clinical knowledge enabled the success of this project: practice, education, administration, and research. The elements of this one situation can be translated into criteria that guide the establishment and maintenance of a TNH, namely: Two critical ingredients: a nursing home and a school of nursing with an undergraduate and a graduate nursing program; A formal agreement that specifies; a shared mission statement; responsibilities in the school and in the nursing home for practice, education, administration, research, and consultation; Clearly defined roles for the nursing faculty in the nursing home, and for the professional nursing staff in the school of nursing; Opportunity for faculty and agency input into respective institutions at all levels, including the highest policy making level; and A steering committee with representation from the school of nursing and the nursing home that guides the functions of the teaching nursing home activities; Depending upon the circumstances, the environment, and the people, other persons may or may not be able to replicate this model. Whether or not replication is possible, there may be some aspects of this experience that will suggest positive avenues to explore with the hope of establishing collaboration linkages, between nursing education and nursing service.

Aged

Sleep and aging.

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Aged