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Biomedical subjects

M Paul

Publications and source records attributed to M Paul.

At least 415 records · Page 23Linked to original sources
PubMed1972

Specific protein synthesis in cellular differentiation. Production of eggshell proteins by silkmoth follicular cells.

Silkmoth follicles, arranged in a precise developmental sequence within the ovariole, yield pure and uniform populations of follicular epithelial cells highly differentiated for synthesis of the proteinaceous eggshell (chorion). These cells can be maintained and labeled efficiently in organ culture; their in vitro (and cell free) protein synthetic activity reflects their activity in vivo. During differentiation the cells undergo dramatic changes in protein synthesis. For 2 days the cells are devoted almost exclusively to production of distinctive chorion proteins of low molecular weight and of unusual amino acid composition. Each protein has its own characteristic developmental kinetics of synthesis. Each is synthesized as a separate polypeptide, apparently on monocistronic messenger RNA (mRNA), and thus reflects the expression of a distinct gene. The rapid changes in this tissue do not result from corresponding changes in translational efficiency. Thus, the peptide chain elongation rate is comparable for chorion and for proteins synthesized at earlier developmental stages (1.3-1.9 amino acids/sec); moreover, the spacing of ribosomes on chorion mRNA (30-37 codons per ribosome) is similar to that encountered in other eukaryotic systems.

Animals↗
PubMed1968

Serological studies in cholera. I. Vibrio agglutinin response of cholera patients determined by a microtechnique.

An agglutinin test for the determination of antibody responses to Vibrio cholerae, requiring only 0.025 ml of serum, has been developed. This microtechnique permits the determination of agglutinin titres using fingertip blood, with results comparable with those obtained using venous blood taken at the same time.Among 364 serum pairs in bacteriologically confirmed cases of cholera from an endemic area of East Pakistan, the second serum sample being obtained 6 days or more after the onset of symptoms, a fourfold rise in agglutinin titre occurred in 77.6% of children under 5 years and in 93.2% of persons 5 years of age or older. This titre rise was quite often demonstrated only against a bacterial suspension of the same serotype as the infecting organism. Among 198 serum pairs in bacteriologically negative cases, a fourfold titre rise against the Inaba suspension only was found in 1 case; 5 other persons with fourfold titre rises proved to be household contacts of cholera patients and are taken to represent bacteriological failures or responses to cholera vaccine rather than false positive serological responses.

Adolescent↗
PubMedDate not supplied

Resection of colorectal liver metastases.

From 1960 to 1992 a total of 1718 patients with liver metastases from colorectal carcinoma were recorded. Of these patients, 469 (27.3%) underwent hepatic resection, which was performed with curative intent in 434 patients (25.3%). Operative mortality in this group was 4.4%, being 1.8% (2 of 114) during the last 3 years. Significant morbidity was observed in 16% of patients with a decrease to 5% (6 of 112) for the last 3 years. A 99.8% follow-up until November 1, 1993 was achieved. Excluding operative mortality, there are 350 patients with "potentially curative" resection and 65 corresponding patients with minimal macroscopic (n = 19) or microscopic (n = 46) residual disease. The latter group demonstrated a poor prognosis, with median and maximum survival times of 14.4 and 56.0 months, respectively. Among the 350 patients having potentially curative resection, the actuarial 5-, 10-, and 20-year survivals were 39.3%, 23.6%, and 17.7%, respectively. Tumor-free survival was 33.6% at 5 years. In the univariate analysis, the following factors were associated with decreased crude survival: presence and extent of mesenteric lymph node involvement (p = 0.0001); grade III/IV primary tumor (p = 0.013); synchronous diagnosis of metastases (p = 0.014); satellite metastases (p = 0.00001); metastasis diameter of > 5 cm (p = 0.003); preoperative carcinoembryonic antigen (CEA) elevation (p = 0.03); limited resection margins (p = 0.009); extrahepatic disease (p = 0.009); and nonanatomic procedures (p = 0.008). With respect to disease-free survival, extrahepatic disease (p = 0.09) failed to achieve statistical significance, whereas patients with primary tumors in the colon did significantly better than those with rectal cancer (p = 0.04). The presence of five or more independent metastases adversely affected resectability (p < 0.05). However, once a radical excision of all detectable disease was achieved, no significant predictive value of an increasing number of metastases (1-3 versus > or = 4) on either overall (p = 0.40) or disease-free (p = 0.64) survival was found. Using Cox's multivariate regression analysis, the presence of satellite metastases, primary tumor grade, the time of metastasis diagnosis, diameter of the largest metastasis, anatomic versus nonanatomic approach, year of resection, and mesenteric lymph node involvement each independently affected both crude and tumor-free survival.

Actuarial Analysis↗
PubMedDate not supplied

Genotoxicity of 'shamma', a chewing material suspected of causing oral cancer in Saudi Arabia.

'Shamma', also known as Yemeni snuff, is frequently used as a chewing material in Yemen and some parts of Saudi Arabia. Preliminary clinical observations indicated that long-term users of 'shamma' may develop oral cancer. A battery of in vitro bioassays were, therefore, used to test genotoxicity of this substance. The test systems included the histidine reversion assay in Ames' Salmonella strains, induction of aberrant colonies and tryptophan gene conversion in the D7 diploid strain of Saccharomyces cerevisiae, and oncogenic transformation of C3H mouse embryo 10T1/2 cells. Data indicated that direct-acting mutagen(s) were present in a chloroform extract of the powdered 'shamma' resulting in positive effects in all of the test systems used. Using high-performance liquid chromatography (HPLC), three major fractions were separated from the extract, of which two were found to be mutagenic.

Animals↗