Biomedical subjects
J Sheridan
Publications and source records attributed to J Sheridan.
Purification and characterization of a novel growth factor from human breast cancer cells.
We have purified and characterized a novel 30-kDa glycoprotein (gp30) with TGF alpha-like properties secreted from the estrogen receptor negative breast cancer cell line MDA-MB-231. This factor was immunoprecipitated by an anti-TGF alpha polyclonal antibody and also had TGF alpha-like biological activity, as assayed by EGF radioreceptor assay and anchorage-independent assays. In addition, the novel growth factor stimulated phosphorylation of the EGF receptor and erbB-2 receptor. However, the novel growth factor, unlike EGF and TGF alpha, bound to heparin-Sepharose. Purification of gp30 was obtained to apparent homogeneity by heparin affinity chromatography and subsequent reversed-phase chromatography. Tunicamycin treatment in vivo or N-glycanase deglycosylation in vitro revealed a putative precursor of approximately 22 kDa molecular mass in contrast to the "normal" 16-kDa precursor species for TGF alpha. In vitro translation of total mRNA from MDA-MB-231 cells confirmed the size of the putative precursor. Biochemical characterization of gp30 was begun by V8 protease digestion of the deglycosylated polypeptide and the translated products. Peptide mapping of V8-digested, immunoprecipitated material suggests that the amino acid sequence of this unique protein is distinct from mature TGF alpha and not the result of a posttranslational modification of the precursor. We conclude that this TGF alpha-like (gp30) polypeptide is a novel growth factor with agonistic activity for both EGF and erbB-2 receptors.
The effects of age on platelet intracellular free calcium concentrations in normotensives and hypertensives.
We have investigated relationships between age, blood pressure and intracellular calcium concentration in platelets from normotensives and hypertensives. In normotensives, there were positive correlations between age and platelet intracellular calcium concentration (r = 0.76, P less than 0.001), age and mean arterial pressure (MAP; r = 0.55, P less than 0.01) and MAP and platelet intracellular calcium concentration (r = 0.45, P less than 0.01). Multiple regression analysis revealed that age was the primary determinant of platelet intracellular calcium concentration in normotensives. The effect of MAP on platelet intracellular calcium concentration when adjusted for age was not significant (P = 0.73). In hypertensives, there was no significant relationship between age and platelet intracellular calcium concentration (r = 0.15, P = 0.43), age and MAP (r = 0.17, P = 0.37) or MAP and platelet intracellular calcium concentration (r = -0.27, P = 0.15). Overall, platelet intracellular calcium concentration was significantly higher in hypertensives than in age-matched normotensives (P less than 0.05). Within the age groups examined, platelet intracellular calcium concentration was significantly higher only in younger hypertensives when compared with controls of a similar mean age (P less than 0.001). Thus, age, in addition to hypertension, is an important determinant of platelet intracellular calcium concentration.
Oesophageal stenosis distal to oesophageal atresia.
Oesophageal atresia with or without tracheo-oesophageal fistula is often associated with a functionally abnormal distal oesophagus. The association of oesophageal atresia and a distal oesophageal stenosis is less well recognized and is usually regarded as a rarity. We describe four cases of oesophageal stenosis distal to oesophageal atresia and review the literature relating to this condition.
Capillary zone electrophoresis: some promising pharmaceutical applications.
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A driver training program for the disabled.
This is a report of results of a driver training program for a selected group of disabled individuals at the Long Beach Veterans Administration Medical Center. A total of 167 eligible candidates elected to enter our driver training program, of whom 154 (92%) were successful. Dropouts were the result of educational deficiencies, physical inability, and/or stress in performance ability.
USP dissolution test II: Sigmoid dissolution profiles from directly compressed tablets.
The basic steps involved in the dissolution of a directly compressed tablet in a USP basket dissolution apparatus were examined via data generation. The proposed model explains why a dissolution curve can be sigmoid shaped and why the portion past the lag time has a log-linear undissolved mass versus time correlation.
USP dissolution III: semilogarithmic dissolution patterns of tablets in rotating-basket assemblies.
The dissolution of a rapidly soluble, finely subdivided substance in a directly compressed tablet and in a wet granulated tablet was treated experimentally and compared with previous theoretical models. The dissolution curves were sigmoid with a semilogarithmic tail when concentration was plotted versus time. As predicted, the slope of the semilogarithmic plots were related to the disintegration decay constant for tablet erosion in the basket.
Subversion of the immune system by tumors as a mechanism of their escape from immune rejection.
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Letter: Aplastic amaemia and hair dye.
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Restoring speech and language skills.
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Congenital vertical talus and its familial occurrence: an analysis of 36 patients.
Thirty-six patients (57 feet) showing congenital vertical talus were treated at the St. Louis Unit of the Shriners Hospital between 1958 and 1978. A high incidence of congenital hip dislocatiom, arthrogryposis, congenital hypoplasia of tibia and CNA disorders was noted as associated abnormalities. These patients are classified in 3 groups: (I) primary isolated form (16 patients); (II) associated form without neurological deficit (12 patients); (III) associated form with neurological deficit (8 patients). Fifty per cent of the patients with primary isolated form had positive family history of foot deformities in their first degree relatives. Familial incidence of congenital vertical talus was observed in 2 families studied. Genetic factors may play an important role in the etiology of the primary isolated form of congenital vertical talus. The current treatment is a one-stage open reduction of the talonavicular dislocation, combined with a posterior release. A subtalar bone block is often imperative to maintain correction. Cast correction alone has never succeeded as the definitive treatment of this condition.