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Biomedical subjects

J Stock

Publications and source records attributed to J Stock.

At least 37 records · Page 2Linked to original sources
PubMed1996

Receptor signaling: dimerization and beyond.

It is has been proposed that hormone receptors which have only a single transmembrane sequence mediate signaling via hormone-induced monomer-to-dimer transitions. But recent studies of analogous receptors in bacteria indicate that dimerization may be only a prerequisite for signaling.

Bacterial Proteins↗
PubMed1996

A specific protein carboxyl methylesterase that demethylates phosphoprotein phosphatase 2A in bovine brain.

Phosphoprotein phosphatase 2A (PP2A) is one of the four major protein serine/threonine phosphatases found in all eukaryotic cells. We have shown that the 36-kDa catalytic subunit of PP2A is carboxyl methylated in eukaryotic cells, and we have previously identified and purified a novel methyltransferase (MTase) that is responsible for this modification. Here, we describe a novel protein carboxyl methyl-esterase (MEase) from bovine brain that demethylates PP2A. The enzyme has been purified to homogeneity as a monomeric 46-kDa soluble protein. The MEase is highly specific for PP2A. It does not catalyze the demethylation of other protein or peptide methylesters. Moreover, MEase activity is dramatically inhibited by nanomolar concentrations of okadaic acid, a specific inhibitor of PP2A. From these results, we conclude that PP2A methylation is controlled by two specific enzymes, a MTase and a MEase. Since PP2A methylation is highly conserved in eukaryotes ranging from human to yeast, it is likely that this system plays an important role in phosphatase regulation.

Amino Acid Sequence↗
PubMed1996

Elevated serum E-selectin in patients with liver metastases of colorectal cancer.

E-selectin, an endothelial cell adhesion molecule, mediates the initial step of leucocyte adhesion to activated vascular endothelium. The soluble isoform of E-selectin promotes angiogenesis in rat cornea. In the present study, we investigated whether leucocyte adhesion and angiogenesis are also involved in tumour progression and metastasis of colorectal cancer. Therefore, we determined the level of circulating soluble E-selectin in serum samples of 38 patients with colorectal cancer; 20 patients with non-metastatic and 18 patients with metastatic disease. Median levels of soluble E-selectin were found to be significantly higher in metastatic tumour disease (88.7 ng/ml, range 25-203 ng/ml) than in healthy controls (34.9 ng/ml, range 15-59 ng/ml, P = 0.01), in patients with primary tumours or with local recurrences (39.5 ng/ml, range 22-100 ng/ml). Furthermore, there was no correlation with the serum level of C-reactive protein, fibrinogen or tumour necrosis factor alpha suggesting that the elevation of E-selectin is independent of inflammation in tumour patients. Therefore, we propose that elevated soluble E-selectin may reflect increased neovascularisation in metastatic tumour tissue.

Adult↗
PubMed1996

Prepare to educate.

Explore the source record for details and available documents.

Contract Services↗
PubMed1995

Proptosis as the initial presentation of fungal sinusitis in immunocompetent patients.

BACKGROUND: Fungal sinusitis typically occurs in immunocompromised patients. The authors report four cases of fungal sinusitis in immunocompetent young adults, all of whom had proptosis. METHODS: The diagnosis in all four patients was determined after orbital imaging and sinus biopsies. RESULTS: All four patients required surgical removal of the fungal source and anti-fungal chemotherapy postoperatively. CONCLUSION: Patients with proptosis, ocular pain, or other symptoms suggestive of orbital cellulitis unresponsive to antibiotic treatment should undergo radiographic imaging. If sinus disease is present, biopsy and culture may lead to the diagnosis of fungal disease. Surgical debridement and the appropriate systemic antifungal therapy usually lead to cure.

Adult↗
PubMed1994

Bacterial chemotaxis. The motor connection.

In bacterial chemotaxis, membrane receptors control the phosphorylation of the response regulator CheY; phospho-CheY has been found to control motility by binding to a switching apparatus attached to the flagellar motor.

Bacterial Proteins↗
PubMed1994

Special report. Human resources.

A new survey reveals the changing shape of human resource departments. Why call in management consultants? Shirley Giles reports. The standard payroll system is being challenged by moves towards integrated payroll and personnel programs. Barbara Millar examines staff support schemes. Trusts are tightening up on relocation packages.

Consultants↗
PubMed1994

Carboxyl methylation of protein phosphatase 2A from Xenopus eggs is stimulated by cAMP and inhibited by okadaic acid.

Protein phosphatase 2A is the principal carboxyl methylated protein in cytoplasmic extracts derived from Xenopus eggs arrested in interphase. Levels of methylation approach stoichiometric values after 2 hr of incubation at 22 degrees C. Rates of PP2A methylation increase by over 50% upon addition of cAMP. Methylation is inhibited by okadaic acid at concentrations that inhibit PP2A phosphatase activity.

Animals↗
PubMed1994

Chemosensing and signal transduction in bacteria.

Major advances have been made over the past year in understanding the molecular mechanisms involved in membrane receptor function, and in resolving the global organization of intracellular signaling pathways. Crystallographic and biochemical studies are revealing details of transmembrane signaling mechanisms and the phosphorylation reactions of the two-component regulatory systems. In addition, the discovery of new signal transduction pathways and new inputs into known pathways are providing a clearer view of the basic architecture of the signal transduction networks within the bacterial cell.

Bacterial Physiological Phenomena↗
PubMed1994

Continuity of care in maternity services--the implications for midwives.

Examines issues raised by Changing Childbirth. Summarizes an IMS/RCM report and is based on research in maternity units at different stages in the adoption of various approaches to developing continuity of care. It is concerned with the effect on midwives' working lives and explores issues of grading, responsibility, working hours, career progression and job satisfaction.

Career Mobility↗
PubMed1994

The labour market for qualified orthotists/prosthetists.

The United Kingdom Health Departments have recently encouraged increased intakes to degree-level training courses leading to a dual qualification in prosthetics/orthotics. Surveys of qualified orthotists and prosthetists and of their employers were undertaken to examine the dynamics of this labour market, and a model was used to project potential requirements for newly qualified orthotists and prosthetists. The model indicates that: current policy on student numbers is broadly appropriate for maintaining the present working population; any expansion in service provision would require significant growth in student places; and even a small decline in demand could shortly lead to an over-supply of such specialist services.

Accreditation↗
PubMed1993

Protein phosphatase 2A catalytic subunit is methyl-esterified at its carboxyl terminus by a novel methyltransferase.

In eukaryotic cells a number of different proteins with important regulatory functions are reversibly methyl-esterified at carboxyl-terminal prenylcysteine residues. These proteins include the low molecular weight GTP-binding proteins, the gamma-subunit of the heterotrimeric G-proteins, and the nuclear lamins. The methylating enzymes that catalyze this type of carboxyl methylation reaction are integral membrane proteins, and the methylated protein products tend to be membrane-associated. Analyses of protein carboxyl methylation in a wide range of vertebrate tissues revealed a major carboxyl-methylated protein that was clearly distinct from those that are modified at prenylcysteine groups (Volker, C., Miller, R.A., McCleary, W.R., Rao, A., Poenie, M., Backer, J.M., and Stock, J.B. (1991) J. Biol. Chem. 266, 21515-21522). This M(r) = 36,000 protein is localized to the cytosol. Unlike the prenylcysteine methyltransferases, the enzyme that catalyzes the methylation of the 36-kDa protein is found in the cytosol. The 36-kDa methylated protein has been purified from bovine brain. Sequence analysis of several peptides clearly shows that the protein is the catalytic subunit of protein phosphatase 2A. A soluble 40-kDa methyltransferase that catalyzes the reaction has also been purified.

Amino Acid Sequence↗
PubMed1993

The supply of orthotist prosthetists. The application of workforce projection techniques in determining future national training places.

Discusses the application of workforce planning techniques in the context of "target" levels of demand and uses a study of the future supply of orthotists and prosthetists as an example. Describes the derivation of an appropriate model, the quantification of the labour market for the profession, and an analysis of the characteristics of the workforce. Information was gathered through two surveys and from discussions with relevant organizations.

Allied Health Personnel↗