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Biomedical subjects

P Bishop

Publications and source records attributed to P Bishop.

At least 55 records · Page 3Linked to original sources
PubMed1994

Responses to repeated days of light work at moderate temperatures in protective clothing.

This study assessed workers' ability to sustain work output over four consecutive workdays in encapsulating protective clothing (PC). Six subjects wearing a two-piece PC ensemble cycled at a work rate of 38 W in a 29/22 degrees C (dry/wet bulb) ambient temperature. Work continued until rectal temperature (Tre) reached 38.3 degrees C, or volitional fatigue. Subjects then rested without PC in a 21 degrees C room until Tre reached 38.0 degrees C to simulate micro- or macro-environmental cooling during rest. Work was alternated with rest for four hours total. Contrary to expectations, mean work time did not diminish on succeeding days. Subject responses to the repeated exposures was highly variable and in no case changed significantly (p > .05) from day one to day four. Subjects tolerated well repeated four-hour exposures with controlled elevations in Tre. There was no clear evidence of either increased or decreased tolerance of this work-rest paradigm across days.

Adaptation, Physiological↗
PubMed1994

Cloning and characterization of a growth factor-inducible cyclooxygenase gene from rat intestinal epithelial cells.

Growth factors have been shown to play a role in intestinal epithelial growth regulation and transformation. Utilizing standard differential cloning techniques, we have isolated a growth factor-inducible gene (RS-2) from rat intestinal epithelial cells that has approximately 95% homology to the mouse mitogen-inducible cyclooxygenase (COX-2) at the amino acid level. This cDNA hybridizes to a approximately 4.5-kb mRNA from transforming growth factor (TGF)-alpha-stimulated rat intestinal epithelial (RIE-1) cells and is constitutively expressed in vivo in adult rat kidney and brain. Nuclear run-on experiments demonstrate that the increase of RS-2 mRNA after TGF-alpha stimulation is in part due to an increased transcription rate of the gene. The coding region for RS-2 was subcloned into a pCMV-2 expression vector, and the RS-2 protein was expressed in COS-1 cells. Microsomal fractions isolated from the COS-1 cells transfected with the RS-2 expression vector contained cyclooxygenase activity. In addition to the production of prostaglandins, the recombinant RS-2 protein also catalyzed the formation of three other eicosanoid products. In summary, we have cloned a mitogen-inducible cyclooxygenase gene from rat intestinal cells that is induced following growth factor stimulation.

Amino Acid Sequence↗
PubMed1993

Signal transduction through a biomolecular receptor tyrosine protein kinase composed of a platelet-derived growth factor receptor-CD4 chimera and the nonreceptor tyrosine protein kinase Lck.

We have generated a novel "receptor tyrosine kinase" by fusing the extracellular and transmembrane domain of the mouse platelet-derived growth factor receptor (PDGFR) to the cytoplasmic domain of CD4 and coexpressing the construct with the murine cytoplasmic tyrosine protein kinase p56lck. NMuMG cells, which are mouse mammary gland epithelial cells that lack endogenous platelet-derived growth factor (PDGF) receptor expression, were stably transfected with both PDGFR-CD4 and p56lck. The PDGFR-CD4 chimeric protein was expressed at the cell surface and formed a complex with p56lck. Addition of PDGF to these cells led to increased tyrosine phosphorylation of a 56-kDa protein likely to be p56lck and several unidentified cellular proteins. The enzymatic activity of p56lck was increased after treatment with PDGF, indicating that dimerization (or oligomerization) mediated by ligand binding at the cell surface is capable of inducing the activation not only of receptor tyrosine kinases but nonreceptor tyrosine kinases as well. However, the PDGFR-CD4.p56lck complex was, in contrast to the wild type PDGF receptor, not able to induce a PDGF-dependent mitogenic response or DNA synthesis in NMuMG cells. Analysis of several known substrates of the PDGFR-signaling pathway indicates an early block in the transduction of the signal generated by p56lck.

Amino Acid Sequence↗
PubMed1993

Prevalence of chronic fatigue syndrome-related symptoms among nurses.

Chronic Fatigue Syndrome is an illness that is characterized by debilitating fatigue and a group of other related symptoms. Few epidemiological studies have been conducted, and none have focused on a nursing population. The present study is the first to assess the prevalence of Chronic Fatigue Syndrome-related symptoms in a sample of nurses. Demographic characteristics, symptoms, and possible prevalence rates are presented and discussed. When using both narrow and more inclusive criteria to define this symptom complex, higher rates of this disorder were found than in previous epidemiological studies. The implications of these findings are discussed.

Adult↗
PubMed1992

Extraction and characterisation of the intact form of bovine vitreous type IX collagen.

We provide the first biochemical characterisation of intact type IX collagen extracted from bovine vitreous. It possesses a shortened alpha 1(IX) chain (M(r) 64K) compared to its cartilage counterpart (M(r) 84K). All the vitreous type IX collagen is in a proteoglycan form, its glycosaminoglycan constituent being a chondroitin/dermatan sulphate component of M(r) 15-60K attached to the alpha 2(IX) chain. This contrasts with previous findings in chick vitreous where a very long glycosaminoglycan chain of M(r) approximately 350K was demonstrated.

Animals↗
PubMed1992

In vitro activity of meropenem and other agents against oral bacteria.

The susceptibility of 106 oral bacteria to meropenem, a new carbapenem antimicrobial, penicillin V, tetracycline and metronidazole was assessed by an agar dilution method. Meropenem was the most effective of the antimicrobials, with all strains tested being inhibited at < or = 1 mg/l. A number of strains were resistant to penicillin V, particularly Bacteroides gracilis, and tetracycline resistance was widespread amongst the streptococci tested. Metronidazole was extremely effective against obligate anaerobes. The results of this study suggest that meropenem has potential for use in the treatment of serious head and neck infections.

Anti-Bacterial Agents↗
PubMed1991

Lipoprotein (a) is a substrate for factor XIIIa and tissue transglutaminase.

The mechanisms which mediate deposition of lipoprotein (a) (Lp(a)), an atherogenic lipoprotein particle, onto the vessel wall and cell surfaces are unknown. An irreversible deposition of Lp(a) may require the presence of enzymes that catalyze its binding to surface-oriented structures. Transglutaminases catalyze cross-linking of proteins as well as incorporation of primary amines into protein substrates. We studied whether tissue transglutaminase and/or activated Factor XIII (plasma derived or recombinant FXIIIa) incorporate primary amines into Lp(a). In the presence of Ca2+, Factor XIIIa and tissue transglutaminase catalyze incorporation of monodansylcadaverine or [14C]putrescine into purified Lp(a) in a specific and time-dependent manner. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis demonstrated that monodansylcadaverine became incorporated into the apo(a) portion of Lp(a). Lp(a) purified from five different donors showing different apo(a) phenotypes were substrates for tissue transglutaminases (TG). Western blot analysis confirmed that apo(a) was the major monodansylcadaverine carrying protein moiety of Lp(a). Tissue TG also extensively cross-linked the apo(a) portion of the Lp(a) particle. Characterization of the specificity of tissue TG showed that fibronectin, alpha 2-plasmin inhibitor, and apo(a) could be readily labeled with monodansylcadaverine by tissue TG, but other proteins including low density lipoprotein, IgG, alpha 1-proteinase inhibitor, and albumin showed poor or no reactivity. Direct comparison of Lp(a) with low density lipoprotein showed that apoB 100 was a poor substrate for transglutaminases. Recombinant apolipoprotein (a) proved to be an excellent substrate for TGs in that 1 mol of recombinant apolipoprotein (a) incorporated as much as 15 mol of [14C]putrescine, which corresponded to five times the amount of amine incorporated into Lp(a). The susceptibility of Lp(a) to transglutaminases suggests a mechanism whereby the interaction of Lp(a) with surface receptors and other surface oriented structures could be enzymatically altered.

Animals↗
PubMed1989

Sex difference in muscle cross-sectional area of athletes and non-athletes.

The purpose of the present study was to determine whether there is a sex difference in limb muscle cross-sectional area by comparing upper- and lower-body limb fat-free cross-sectional areas (FFCSAs) adjusted for differences in fat-free weight (FFW), in male and female athletes with similar histories of upper-body physical conditioning and in non-athletes. Limb FFCSAs were calculated from circumferences corrected for subcutaneous fat thickness and FFW was estimated from body density measured by underwater weighing in 24 male and 25 female swimmers and 23 male and 25 female non-athletes, 15 to 28 years of age. The male swimmers had 32% larger FFWs and 49% larger upper-arm, similar forearm and 23% larger thigh FFCSAs compared to the female swimmers. The male non-athletes had 34% larger FFWs, 61% larger upper-arms, 54% larger forearms and 35% larger thighs than female non-athletes. To adjust for differences in body size, analysis of covariance was performed on the FFCSAs using FFW as the covariate. For the swimmers there were no significant differences (P greater than 0.05) in the adjusted FFCSAs. For the non-athletes, males had significantly larger adjusted upper-arm and forearm FFCSAs than the females but thigh FFCSAs were not significantly different (P greater than 0.05). These results suggest that sex differences in muscle area of the arms, may be partially attributed to long-term activity differences between sexes. Possible long-term differences in activity between sexes should be considered in comparisons of functional or performance measures between sexes.

Adolescent↗
PubMed1986

Purification and characterization of a sulfated glycoprotein secreted by Sertoli cells.

Sulfated glycoprotein 2 (SGP-2), the major secretion product of Sertoli cells, was purified from cell culture medium by reverse-phase high-performance liquid chromatography. The native protein consists of disulfide-linked monomers of 41,000 and 29,000 daltons which have a strong tendency to associate into multimers. The purified SGP-2 was subjected to amino acid analysis and contained high levels of Asx (11.1%), Glx (15.1%), and leucine (11.5%). The oligosaccharides on the purified SGP-2 were analyzed to determine the monosaccharide compositions and the molecular weights of the intact carbohydrate moieties. SGP-2 was shown to be 23.7% carbohydrate and consisted of 1% fucose, 3.5% mannose, 4.1% galactose, 7.1% N-acetylglucosamine, and 8.0% N-acetylneuraminic acid. No N-acetylgalactosamine was detected. When the SGP-2 was digested with proteases, the intact oligosaccharides were chromatographed over a Bio-Gel P-6 column and found to elute in a single symmetrical peak of approximately 3,300 g/mol. On the basis of these results, the oligosaccharides on SGP-2 were proposed to consist of triantennary chains similar to those found on fetuin. When the 35SO4(2-)-labeled SGP-2 was digested with Pronase, the free amino acids could be separated by chromatography from the oligosaccharide. The 35SO4(2-) was shown to be associated with the oligosaccharide portion of SGP-2.

Amino Acids↗