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Biomedical subjects

C S Scott

Publications and source records attributed to C S Scott.

At least 109 records · Page 6Linked to original sources

Black adolescents' emotional response to menarche.

There has been substantial agreement in the literature that cultural attitudes influence females' reaction to menarche. Recently, growing interest has been shown in the ways cultural traditions affect the response to this event. To date, studies of the emotional impact of menarche have involved primarily white middle class populations. To determine whether the black American experience is similar to or different from that of a white American sample, the questions and measure used previously on a white sample were replicated in a group of middle class black adolescents. Although the black and white mean scores on positive feelings were similar (slightly positive), the blacks indicated somewhat greater negative feelings than did the whites. The black perception of menarche as more negative than positive is in accord with findings from other studies concerning the reaction to this event in this culture. Several explanations are suggested as possible bases for the negative feelings surrounding first menstruation in the United States.

Adolescent↗

TdT expression in acute myeloid leukaemia. Haemopoietic immaturity or maturational asynchrony?

A total of 412 cases of acute leukaemia were examined for the presence of nuclear terminal deoxynucleotidyl transferase (TdT) by indirect immunofluorescence. Of the 129 cases of acute myeloblastic leukaemia (AML FAB groups M1/M2) examined, 18% (n = 23) had significant proportions (greater than 10%) of TdT-positive blasts. Although most of these AML cases (n = 18) were of poorly differentiated (M1) type; 5 cases of AML showing features of granulocytic differentiation (M2) were also found to be TdT-positive. Even though TdT was generally more strongly expressed in the M1 group and associated with other markers of myeloid immaturity (Ia positive and lack of chloroacetate esterase), there was no inverse relationship with Sudan black or myeloperoxidase activity. In addition, although the proportion of AML-M1 cases with increased TdT-positive cells was slightly higher (18/95, 19%) than for the AML-M2 group (5/34, 15%) the results suggest that the presence of nuclear TdT in leukaemic myeloblasts may not only reflect cellular immaturity but may also be due to maturational asynchrony in otherwise well-differentiated blasts.

Bone Marrow↗

Expression of MHC class I and class I-like gene products on the cell membrane of mature and immature T cells.

Beta 2-microglobulin (beta 2m) constitutes the 12 kD light chain of the MHC-encoded 43-kD glycoprotein HLA-ABC molecules, which are expressed on most nucleated cells. The T6 (CD1a) antigen is expressed on thymocytes in reciprocal manner to HLA-ABC, having a similar structure to the HLA-ABC molecule. We have determined the expression of beta 2m, HLA-ABC and the T6 antigen on the cell-surface of CD1a+ and CD1a- thymocytes (defined by NA1/34 expression), and have shown that despite immunophenotypic differences between these two stages of thymic maturation, the quantity of beta 2m-associated molecules expressed was not significantly different. The nature of the heavy (alpha) chain associated with beta 2m, however, differed since HLA-ABC had largely replaced T6 on the surface of CD1a- thymocytes. We also determined the expression of beta 2m and HLA-ABC on the surface of peripheral blood CD4+ and CD8+ T-cells, and showed that the CD8+ population expressed higher levels of these antigens than CD4+ T-cells, with no detectable excess beta 2m over HLA-ABC for either subpopulation. In addition, thymocytes expressed fewer beta 2m-associated determinants than peripheral blood T-cells. These results indicate an increase in the expression of beta 2m-associated molecules with differentiation from thymic to peripheral T-cell, with a further increase in such molecules expressed on the CD8+ compared to the CD4+ peripheral T-cell subpopulation.

Antigens, Differentiation, T-Lymphocyte↗

Quantitative and qualitative studies of leukaemic cell dipeptidylpeptidases II and IV.

Cellular concentrations of dipeptidylpeptidases (DAP) II and IV were determined by fluorimetric assay in 152 cases of leukaemia and 24 permanent T-cell lines. Whilst its estimation appears to have few diagnostic applications, it was found that DAPII levels were generally higher in prolymphocytoid CLL variants (CLL-Pro) compared with "typical" CLL cases. Qualitatively, DAPII extracted from leukaemic B- and T-cells did not differ significantly with respect to molecular weight (Mr 82 kD: FPLC gel filtration) or substrate affinity (Km). Similarly, a single molecular weight species (Mr 189 kD) of DAPIV was also detected in all leukaemic sonicates examined although, in quantitative terms, increased DAPIV levels were primarily associated with a subgroup of CD4-positive postthymic malignancies. Studies of immature T-cell proliferations however indicated that DAPIV expression was unrelated to either stage of immunological differentiation or CD4 expression. No evidence of lineage restriction was found for either enzyme and it is concluded that variations in DAP cytochemical staining patterns reflect quantitative rather than qualitative differences.

Antigens, Differentiation, T-Lymphocyte↗

Diagnostic and prognostic factors in acute monocytic leukaemia: an analysis of 51 cases.

Diagnostic features (cytochemistry, immunophenotyping and serum biochemistry) were examined in 51 cases of acute monocytic leukaemia (AMoL). Peroxidase, Sudan black B and alpha naphthyl acetate esterase (ANAE) cytochemical reactions were unrelated to morphological (FAB groups M5a and M5b) or immunological subtype. ANAE cytochemistry, however, indicated that AMoL cases could be subdivided into those with typical (M-type) reactions and those with insignificant staining or monocytic ANAE isoenzymes (defined by IEF). All cases were phenotypically CD13/CD33 positive and, with one exception, had greater than 30% HLA-DR positive cells. Membrane CD14 expression was insignificant or variable in 33% of M5a cases in contrast to 23/24 M5b cases which showed high proportions of CD14-staining cells with at least two monoclonal antibodies. Serum lysozyme, LDH and beta-2 microglobulin (beta 2m) were increased in 88%, 68% and 81% of cases respectively but, with the exception of statistically higher lysozyme levels in CD14+ cases, were unrelated to the morphological, cytochemical or immunological diagnostic subgroups. Clinical and diagnostic features were also examined as possible prognostic indicators. The morphological, cytochemical and immunological subgroups of AMoL were not found to be of prognostic relevance but age (P = 0.004), renal failure (P = 0.005) and serum beta 2m levels (P = 0.002) were related to patient survival. Moreover, renal failure and serum beta 2m remained significant (P = 0.012 respectively) when age was taken into account and were shown to be independent prognostic variables.

Acute Disease↗

Early identification of future medical students using initial undergraduate grades.

This study assessed whether overall academic performance in undergraduate medical coursework can be predicted with reasonable accuracy by using grades from initial college-level courses rather than total premedical grade point averages (GPAs). Initial college grades from four areas, MCAT scores, and NBME I and II scores were recorded for students admitted to the University of Washington Medical School, for students admitted to other medical schools, and for students not admitted to any medical school. The results documented a high relationship between cumulative GPAs and initial grades, with differences found between those students admitted to medical school and those not admitted. The importance of this study is the documentation that little predictive utility is gained by waiting for overall college GPAs from medical school applicants. Initial GPAs are available 2 years earlier than overall GPAs and provide virtually the same information. Exploratory suggestions for medical school admission policies are made.

Achievement↗

MHC class I and class I-like gene product expression by malignant T cells: relationships between CD1a, HLA-ABC and beta 2-microglobulin.

Beta 2-microglobulin (beta 2m) forms the invariant light chain of the MHC-encoded HLA-ABC and the non-MHC-encoded CD1 molecules. While HLA-ABC (MHC Class I) molecules are virtually ubiquitous in tissue distribution, CD1 determinants by contrast are more restricted. We have assessed, by indirect immunoenzymeassay, the relative membrane densities of these molecules on malignant thymic and post-thymic T cells. It was found that the T cells of mature post-thymic proliferations expressed significantly more beta 2m-associated protein, predominantly HLA-ABC in nature, than thymic-ALL blasts. This parallels the situation found in normal peripheral T cells and thymocytes. In contrast to post-thymic T cells, thymic-ALL blasts showed considerable case to case variation with respect to non-HLA-associated beta 2m and, of particular interest, not all of this excess beta 2m could be accounted for by CD1a. We therefore conclude that other beta 2m-containing molecules may be expressed on thymic-ALL blasts and possibly also on post-thymic leukaemic T cells. In addition, it was found that T cells from CD4+ cases of post-thymic proliferations expressed more beta 2m-associated determinants than other T cells, whether of either normal or malignant origin, and that certain post-thymic malignancies express significantly increased levels of beta 2m-associated protein relative to normal peripheral T-cells. This is in direct contrast to the situation seen in many solid malignancies.

Antigens, Differentiation↗

Membrane transferrin receptor (TfR) and nuclear proliferation-associated Ki-67 expression in hemopoietic malignancies.

The expression of membrane transferrin receptors (TfRs), as defined by monoclonal antibody OKT9, and the nuclear proliferation-associated antigen Ki-67 were examined in 159 cases of hematological malignancy. Of the "chronic" B and T cell leukemias studied (n = 85), 61% showed less than 5% OKT9-positive cells and only 7% of cases were TfR+ (defined as greater than 20% positive cells). For comparison, the acute leukemias (n = 62) showed higher (p less than 0.001) TfR expression with 39% TfR+ cases, although there was considerable variation within diagnostic subgroups. Nuclear Ki-67 expression was generally insignificant (less than 1%) in chronic leukemias (78 of 88 cases), although two of eight B cell-type prolymphocytic leukemia and four of four cases of plasma cell leukemia showed greater than 10% Ki-67+ components. In contrast, 47% (31 of 66) acute leukemias had greater than 10% Ki-67+ cells, although there appeared to be no relationship between Ki-67 expression and leukemic type. Combined assessments of TfR and Ki-67 expression revealed a Ki-67- TfR- phenotype in 82% of chronic leukemias, compared with 28% of acute type, and a Ki-67+ TfR+ pattern was found in 27% of acute proliferations but not in any case of chronic leukemia. The determination of membrane TfR expression appears to have little value in the diagnostic differentiation of leukemias, whereas Ki-67 is considered to be a useful supplementary investigation in defining high grade tumors, in the recognition of prognostically poor cases of otherwise well defined low grade malignancy, and of potential value in resolving discrepancies between morphological and immunophenotypic features in leukemias of "intermediate" type.

Acute Disease↗

Quantitative and qualitative enzyme studies of Hodgkin's disease-derived cell lines.

Any extensive analysis of Hodgkin (H) and Reed-Sternberg (RS) cells is limited by the scarcity of available material and by the common contamination with "by-stander" cells. The establishment of Hodgkin's disease-derived cell lines provides the opportunity to undertake studies in which large numbers of cells are required, as these cell lines are by definition monoclonal populations with unlimited cell growth. In this study, we analyzed the enzyme profiles of eight Hodgkin's disease cell lines (Co, Ho, Fox, HDLM-2, KM-H2, L428, L540, and L591) whereby cellular alpha-naphthyl acetate esterases, acid phosphatases, and dipeptidylpeptidase IV were examined quantitatively or qualitatively by IEF or chromatographic techniques. The results indicate that all of the H-RS cell lines examined had enzymatic features typical for lymphoid cells and, in particular, a monocyte/histiocyte origin of the cell lines could be excluded. Extrapolation of the available immunological, molecular biological, and enzymological evidence gained in vitro on cultured representatives of H-RS cells suggests a lymphoid origin for in vivo H-RS cells.

Acid Phosphatase↗

Hispanic and black American adolescents' beliefs relating to sexuality and contraception.

Popular beliefs and level of scientific knowledge regarding sexuality and contraception were elicited from black and Hispanic inner-city adolescents. Significant differences were found: Hispanic males were the most knowledgeable, Hispanic females the least, and black males and females were intermediate. A cultural basis for the dramatic difference between Hispanic male and female scores is suggested and the need to design culturally appropriate sexuality education classes is discussed. In addition, the data depicted two conflicting beliefs that were held simultaneously by many of the adolescents: Contraception is "good" because it prevents pregnancy, and it is "bad" because the various birth control methods carry serious health hazards for users.

Adolescent↗

Prolymphocytoid variants of chronic lymphocytic leukaemia: an immunological and morphological survey.

Of 417 cases of chronic lymphocytic leukaemia (CLL) examined morphologically, 346 (83%) showed low (less than 10%) numbers of cells with prolymphocytoid (PLC) morphology. Immunological studies in 267 of these cases, with particular reference to membrane surface immunoglobulin (SIg) densities and FMC7 expression, revealed that of 223 cases with insignificant prolymphocytoid components, 185 were phenotypically consistent with typical CLL whilst the other 38 cases showed significant (greater than 20% positive cells) FMC7 expression and/or increased SIg density. In contrast, 40 of the 44 cases with greater than 10% PLC showed atypical immunophenotypic features even though the expression of individual membrane components associated with B-cell differentiation appeared to be unrelated. MRBC receptor expression showed little correlation with the degree of prolymphocytoid change although all TU1- cases showed greater than 10% PLC. The results suggest that abnormal phenotypic features, similar to those observed in "prolymphocytoid" transformation, may be found in cases of CLL in the absence of morphological change.

Antigens, Neoplasm↗

Fast protein liquid chromatography (FPLC) of leukaemic cell N-acetyl beta-D hexosaminidases.

Leukaemic myeloid and lymphoid cell N-acetyl beta-D glucosaminidase (hexosaminidase) enzymes were fractionated by Fast Protein Liquid Chromatography (FPLC) using high-resolution ion exchange (Mono-S and Mono-Q), gel filtration (Superose-6) and chromatofocusing (Mono-P) columns. Although only one molecular weight species was detected in haemopoietic cells, with an apparent mass of 129 kD, "isoenzyme" variants defined by differences in molecular charge were considerably more diverse than previously thought. Separation of the major Hex forms (A and B) by chromatofocusing indicated that intermediate (I) components were present in most acute leukaemias irrespective of lineage supporting the concept that the I form is a non-specific marker of haemopoietic immaturity. Substrate and inhibitor studies further revealed that leukaemic cell hexosaminidases hydrolyse galactopyranosides at significantly lower rates than glucopyranosides and that the hydrolysis of N-acetyl beta-D glucosamine is inhibited by both glucosamine and galactosamine products.

Acetylglucosaminidase↗

Diagnostic differentiation between reactive and malignant lymphoid cells in serous effusions.

Lymphoid cell components in a total of 34 pleural and ascitic aspirates were investigated immunologically. The results indicate that reactive lymphocytes predominate in effusions from non-haemopoietic malignancies and benign conditions, while a significant proportion of fluids from patients with non-Hodgkins lymphoma show unequivocal evidence of lymphomatous involvement. Immunological typing of lymphocytes in serous effusions is a valuable adjunct to conventional methods of diagnosis particularly in those patients in whom invasive procedures are undesirable.

Ascitic Fluid↗

Prognostic factors and survival in chronic myelomonocytic leukaemia (CMML).

Ninety-seven cases of chronic myelomonocytic leukaemia (CMML) were examined retrospectively for survival and possible prognostic factors including age, total white cell count, peripheral blood and bone marrow monocyte counts, % double esterase (DE) positive cells in bone marrow and serum lysozyme. Age, absolute monocyte counts and serum lysozyme proved to be significant independent prognostic indicators but Cox model analyses showed serum lysozyme to be the most important factor whether taken as a continuous or discrete (two groups) variable. Twelve cases of second malignancy were found, including 2 cases of multiple myeloma, but this was not significantly greater than expected when compared with an age and sex matched group.

Aged↗

Performance of residents who had academic difficulties in medical school.

An assessment of how well graduates of one medical school performed in residency training was undertaken to assess the school's monitoring of students' performances. The minutes of the school's student progress committee for four years were reviewed to identify all students who had had academic difficulty. Seven students had been recommended for dismissal but ultimately graduated, 22 students were on academic probation for longer than one year, and 22 students were on academic probation for less than one year. The residency performance of 43 of these 51 students were compared with the performances of a randomly selected group of students who had had no academic difficulties and had graduated during the same period. Of 12 performance and knowledge items assessed by the residency directors for the studied graduates, the one dealing with quality of interaction with patients showed significant differences among the residents. The residents who had had academic difficulty had lower ratings on this item than the residents who had not had academic trouble. On all other items, those residents who had had academic difficulties received generally lower scores than the other residents, but the differences were not statistically significant. Of the seven students considered for dismissal, one had been dismissed and one had withdrawn from the residencies; the other five generally received positive ratings from their residency directors. The findings suggest that the medical school's overall monitoring of students' performance was working and confirmed the authors' opinion that each decision concerning a student with academic difficulties should be based on the student's individual situation.

Educational Measurement↗