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M E Powell

Publications and source records attributed to M E Powell.

28 records · Page 2Linked to original sources
PubMed1979

Isolation and characterization of gangliosides with a new sialosyl linkage and core structures. II. Gangliosides of human erythrocyte membranes.

Eight monosialosylgangliosides, G1 to G8, have been isolated from human erythrocyte membranes and their structures have been determined. Gangliosides G4 and G7 have been characterized by having 2 leads to 6-linked sialic acid to galactose at their termini. Ganglioside G5 was a positional isomer of a brain ganglioside GM1 as to the linkage of sialic acid. Ganglioside G8 was characterized as a branched chain ganglioside similar to a fucoganglioside previously isolated but devoid of fucose, and it showed a strong blood group I activity. Structures of these four new gangliosides are shown below: (formula: see text).

Carbohydrates↗
PubMed1978

Blood-group-Ii-active gangliosides of human erythrocyte membranes.

More than ten new types of gangliosides, in addition to haematoside and sialosylparagloboside, were isolated from human erythrocyte membranes. These were separated by successive chromatographies on DEAE-Sephadex, on porous silica-gel columns and on thin-layer silica gel as acetylated compounds. Highly potent blood-group-Ii and moderate blood-group-H activities were demonstrated in some of the ganglioside fractions. The gangliosides incorporated into cholesterol/phosphatidylcholine liposomes stoicheiometrically inhibited binding of anti-(blood-group I and i) antibodies to a radioiodinated blood-group-Ii-active glycoprotein. The fraction with the highest blood-group-I-activity, I(g) fraction, behaved like sialosyl-deca- to -dodeca-glycosylceramides on t.l.c. Certain blood-group-I and most of the -i determinants were in partially or completely cryptic form and could be unmasked by sialidase treatment. Thus the I and i antigens, which are known to occur on internal structures of blood-group-ABH-active glycoproteins in secretions, also occur in the interior of the carbohydrate chains of erythrocyte gangliosides.

Blood Group Antigens↗
PubMed1977

Atypical stromal hyperplasia of the prostate gland.

Hyperplastic lesions of the prostatic stroma with atypical changes are presented and discussed. One lesion was a leiomyoma with atypical organization and a limited area of nuclear pleomorphism without mitotic figures. One was a lesion which in many portions was histologically indistinguishable from leiomyosarcoma. It, however, had certain features probably connoting less sinister behavior, and at autopsy 16 months after resection there was no evidence of recurrence or metastasis. One lesion histologically resembled fibroadenoma of the female breast. These three lesions occurred in patients more than 50 years who had symptoms and signs of prostatism. Reference is made to two previously reported lesions reminiscent of cystosarcoma phyllodes of the female breast. All the lesions were located in the craniad prostate, which is estrogen-influenced. A parallel is drawn between these atypical changes in prostatic fibromuscular stroma and atypical changes in the connective tissue stroma of the female breast.

Adenofibroma↗
PubMedDate not supplied

Selected options supporting use of the group embedded figures test in modeling achievement in clinical laboratory science programs.

OBJECTIVE: To identify, in light of predicted future shortages of allied-health personnel, student and curricular characteristics of clinical laboratory science (CLS) programs relevant to recruitment and retention at the baccalaureate level. SETTING: Not applicable. PRACTICE DESCRIPTION: Not applicable. PRACTICE INNOVATION: Options for modeling achievement in CLS programs are developed, and designs and procedures for clarifying procedural questions are considered in a context of delivery of instruction for specialized curricula and skill development. Considerable attention is given to the potential for using the Group Embedded Figures Test (GEFT) in modeling, advising, designing curricula, and monitoring quality improvement of programs and graduates. MAIN OUTCOME MEASUREMENT: Not applicable. RESULTS: Supporting evidence is supplied from the literature for options in developing an appropriate model for examining those salient variables known to have linkages to achievement. CONCLUSION: An argument is presented for better understanding of antecedent variables affecting achievement and retention of CLS students. In addition, a case is made for development of an appropriate model examining variables identified in the literature as being linked to achievement. Dynamic models based on these considerations should be developed chronologically from entry through graduation with emphasis on growth at year-end milestones.

Achievement↗