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.
Explore the source record for details and available documents.
An evaluation of drug testing in the workplace.
Explore the source record for details and available documents.
The need for a standardized protocol for validating non-invasive ambulatory blood pressure measuring devices.
Increasing interest in ambulatory blood pressure measurement has resulted in the proliferation of non-invasive measurement systems. This paper discusses the problems associated with validation of these systems. There is an urgent requirement for a standardized protocol for validation of ambulatory systems which is practicable, universally applicable and which is acceptable to investigators, publishing houses and the manufacturing industry.
Application of cusums to ambulatory blood pressure data: a simple statistical technique for detecting trends over time.
Explore the source record for details and available documents.
Dippers and non-dippers.
Explore the source record for details and available documents.
The perceived value of required research in orthodontic postdoctoral training.
Explore the source record for details and available documents.
Rapid method for purification of human T lymphocytes for further functional studies.
We have evaluated a commercially available reagent, T Lympho-kwik, for ability to provide enriched, functional human T cell populations. We have found that this method is more rapid, reliable and efficient than other available methods of T cell isolation and/or macrophage depletion. Although the T Lympho-kwik-treated peripheral blood mononuclear cells (PBMC) are enriched for T cells, devoid of macrophages, and are not activated by the T Lympho-kwik reagent, they can be induced to proliferate, secrete lymphokines and/or develop alloreactive cytolytic T cell activity under appropriate experimental conditions. Hence, T Lympho-kwik treatment of PBMC is a highly effective technique for providing enriched T cells that are free of accessory cells and that can be used for further functional studies.
Stress-related immune suppression: health implications.
This study used a year-long prospective design to assess linkages among distress, immunity, and illness. Serial blood samples were collected from 40 first-year medical students at the first, third, and fifth examination periods, as well as 1 month before each. There were significant decrements in the production of gamma-interferon by concanavalin A-stimulated lymphocytes obtained at the time of examinations. Antibody titers to Epstein-Barr virus (EBV) increased during examination periods, suggesting reactivation of latent EBV and therefore poorer cellular immune control of latent virus. We obtained data that suggest that T-cell killing by memory T lymphocytes of EBV transformed autologous B lymphocytes also declined during examination periods. The activity of a lymphokine, leukocyte migration inhibition factor, normally suppressed during recrudescence of herpes simplex virus type 2 infections, was altered during examination periods and an increase in both plasma and intracellular levels of cyclic AMP associated with examination stress was observed. An increase in the incidence of self-reported symptoms of infectious illness was also associated with examination periods. The data support the linkage between stress-related immunosuppression and health.
Ulcerative colitis complicated by disseminated intravascular coagulation.
We report a case of chronic ulcerative colitis complicated by clinical evidence of disseminated intravascular coagulation and pathological evidence of intestinal ischaemia secondary to venular and capillary fibrin thrombi. This may well represent an example of univisceral Shwartzman reaction occurring in a sensitized target organ.
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.
Explore the source record for details and available documents.
Letter: Aplastic amaemia and hair dye.
Explore the source record for details and available documents.