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Biomedical subjects

P Roper

Publications and source records attributed to P Roper.

6 recordsLinked to original sources
PubMed1992

Renal cell cancer among paperboard printing workers.

A physician's alert prompted us to investigate workers' cancer risk at a paperboard printing manufacturer. We conducted a retrospective cohort mortality study of all 2,050 persons who had worked at the facility for more than 1 day, calculated standardized incidence ratios (SIRs) for bladder and renal cell cancer, and conducted a nested case-control study for renal cell cancer. Standardized mortality ratios (SMRs) from all causes [SMR = 1.0, 95% confidence interval (CI) = 0.9-1.2] and all cancers (SMR = 0.6, 95% CI = 0.3-1.0) were not greater than expected. One bladder cancer and one renal cell cancer were included in the mortality analysis. Six incident renal cell cancers were observed, however, compared with less than two renal cell cancers expected (SIR = 3.7, 95% CI = 1.4-8.1). Based on a nested case-control analysis, the risk of renal cell cancer was associated with overall length of employment but was not limited to any single department or work process. Although pigments containing congeners of dichlorobenzidine and o-toluidine had been used at the plant, environmental sampling could not confirm any current exposure. Several limitations and a potential selection bias limit the inferences that can be drawn.

Adolescent↗
PubMed1979

Effects of time, platelet concentration, and sex on the human platelet aggregation response.

The platelet aggregation responses induced by adenosine diphosphate (ADP) and collagen were characterized by parameters defining rate and extent of reaction. Values were compared on the basis of platelet concentration, time elapsed between sample collection and test performance, and sex of donors. Rate and extent of aggregation varied as a function of platelet concentration. Maximal responses were obtained for platelet concentrations greater than 100,000/microliter. Results from samples processed after 90 min of incubation at room temperature were consistently and significantly lower than those obtained from samples processed immediately. ADP-induced aggregation responses elicited by samples from male and female normal donors differed significantly. This indicates that comparisons between normal and patient results should be made with sex-matched individuals to avoid erroneous interpretations.

Adenosine Diphosphate↗
PubMed1977

Performance testing of the NIOSH charcoal tube technique for the determination of air concentrations of organic vapors.

The use of the charcoal tube-gas chromatographic method to evaluate workplace air contamination has proliferated greatly in the las 10 years. This report documents early efforts by NIOSH researchers to evaluate several sampling and analytical parameters and their effect on the reliability of the technique. The effects of humidity, sample stability, sample migration and variations in the desorption efficiency are presented. A protocol is suggested for basic testing of the method for new substances.

Air Pollutants↗
PubMed1977

Inhibition of ristocetin-induced platelet agglutination by vancomycin.

Ristocetin and vancomycin are structurally similar glycopeptide antibiotics. Both vancomycin and ristocetin in high concentrations (3.0 mg/ml) cause the precipitation of fibrinogen, plasminogen, and IgG from platelet-poor plasma (PPP). In contrast to ristocetin, vanomycin (0.5-1.5 mg/ml) does not agglutinate platelets in normal platelet-rich plasma (PRP) or formalin-treated platelets in the presence of normal PPP. Preincubation of vancomycin (0.5-1.25 mg/ml) with normal PRP, von Willebrand platelets in normal PPP, or formalinized platelets results in inhibition of platelet agglutination induced by ristocetin (0.7-1.25 mg/ml) or ristocetin and normal PPP. This inhibition can be overcome by increasing the final concentration of ristocetin in the platelet suspension. Preincubation of formalin-treated platelets with the major fraction obtained by carboxymethyl-Sephadex C-50 chromatography of commercial vancomycin also results in inhibition of agglutination induced by ristocetin and normal PPP. Incubation with vancomycin (1.25 mg/ml) does not interfere with von Willebrand factor (vWF) or factor VIII coagulant activities in normal PPP or in Sepharose 4B void volume fractions of PPP. These results indicate that vancomycin interacts with normal, von Willebrand, and formalin-treated platelets and inhibits the binding of ristocetin (or ristocetin-vWF complexes).

Binding, Competitive↗