Study of enzymatic digestion of cellulose by small angle neutron scattering.

Small angle neutron scattering (SANS) was used to study the structure of Avicel (FD100) microcrystalline cellulose during enzymatic digestion. Digestions were performed in either of two modes: a static, quiescent mode or a dynamic mode using a stirred suspension recycled through a flow cell. The scattering pattern for as-received Avicel in D(2)O buffer is comprised of a low Q power law region resulting from the surface fractal character of the microcrystalline fibers and a high Q roll-off due to scattering from water-filled nanopores with radii approximately 20 A. For digestions in the dynamic mode the high Q roll-off decreased in magnitude within approximately 1 h after addition of enzymes, whereas in the static digestions no change was observed in the high Q roll-off, even after 60 h. These results indicate that only with significant agitation does enzyme digestion affect the structure of the nanopores.

[Experience and knowledge about climateric and menopause in women in Mexico City]. / Experiencias y conocimientos sobre climaterio y menopausia en mujeres de la ciudad de México.

OBJECTIVE: To know the experiences and knowledge about climateric and menopause in a group of women covered by Instituto Mexicano del Seguro Social (IMSS). The purpose was to contribute for planning some strategies to increase seeking for medical care at these periods of life. MATERIAL AND METHODS: Descriptive survey study in a randomized sample of women aged 50-59 years, currently users of medical services in family medicine system of IMSS en Mexico City, with a confidence interval of 95%. RESULTS: Mean age at menopause was 47.8 years. Most frequent climateric symptoms were: hot flushes (70.9%), depression (60.2%), insomnia (53.5%) and menstrual disturbances (37.8%). 51.1% of women seeked medical care due to climateric symptoms but only 12.1% received treatment, majority hormonals (81.6%). Past users were 14.9% and they received hormones too in 87.8%. In this survey, 83.8% of women had some knowledge about main symptoms of climateric and 90.1% knew about osteoporosis but only 37.2% had some knowledge about cardiovascular risk after menopause. The prevention of osteoporosis and coronary disease was associated with calcium and exercise; only in 1% with use of hormonals. CONCLUSIONS: It exists an acceptable level of information about climateric syndrome and postmenopausal osteoporosis in these women, but it is low for risk of cardiovascular disease. Probably, their information is got from the mass media communication and did not for the activities of medical institutions in health education.

An unusual complication of appendicitis in childhood.

Mesenteric venous thrombosis has not been reported after an appendicectomy in the pediatric literature. We report on a special and very unusual complication in a girl who presented mesenteric venous thrombosis (MVT) following an appendicectomy for gangrenous appendicitis. The early diagnosis of this entity is vital in order to start the anticoagulation treatment which could allow preservation of bowel viability. The therapy should be continued for a long time to decrease the risk of relapse.

Myelomonocytic myeloma cell line (LB 84-1).

A human cell line (LB 84-1) has been established from the bone marrow of a patient with Bence-Jones myeloma. Coexpression of plasma cell (Leu[CD38]) and myelomonocytic antigens (Leu MI[CD15], Leu M5 [CD11c], MY7 [CD13] plus butyrate and chloracetate esterase) proved to be an unusual but sustained feature of this cell line. The plasma cell phenotype with multinuclearity was retained. Shared major chromosomal abnormalities (del [5] [p14], t[5;?] [q35;?], del [6] [q21], and del 7[q32]) between the direct and cell line karyotypes affirmed the LB 84-1 cell as being derived from the original patient myeloma clone. The mechanisms potentially responsible for the aberrant coexpressed phenotype are discussed. This myelomonocytic myeloma cell line will hopefully prove to be a valuable tool for the study of the genotypic and phenotypic evolution of human myeloma.

Entamoeba histolytica: cytopathogenicity and lectin activity of avirulent mutants.

Three clones of Entamoeba histolytica (L-6, C93, C919) were isolated by mutagenesis with ethyl methanesulfonate from the axenic strain HM1:IMSS and were studied for adherence, cytolytic, and soluble galactose inhibitable lectin activity. Avirulent clones adhered to and killed fewer Chinese hamster ovary cells than HM1:IMSS (P less than 0.01). However, only C919 was deficient in adherence to red blood cells. Galactose (1.0 g) completely inhibited adherence of all the mutants to Chinese hamster ovary cells; however, adherence to erythrocytes was only partially inhibitable by galactose. Avirulent mutants were more susceptible to being killed by human neutrophils in vitro (P less than 0.01 compared to HM1:IMSS). Soluble protein preparations from all the avirulent mutants were markedly less mitogenic for human lymphocytes and had lower lectin activity for Chinese hamster ovary cells compared to the HM1:IMSS wild type (P less than 0.01 for each activity with each mutant). Indirect immunofluorescence with a monoclonal antibody (F-14) that recognizes the Gal/GalNAc lectin was positive for L-6 and C919. These findings utilizing avirulent mutants of E. histolytica further support a role for the amebic galactose inhibitable lectin in the in vivo pathogenesis of amebiasis.