Synthesis of coagulation factor V by cultured aortic endothelium

Bovine aortic endothelium has been examined with respect to the synthesis of coagulation factor V. After cultured cells reached confluency, samples of supernatant culture media and solubilized cells were analyzed for factor V in a two-stage bioassay and in a double- antibody radioimmunoassay. In addition, preconfluent cells were pulsed for 4 days with 35S-methionine in methionine-free media. After the 4- day pulse, supernatant media were chromatographed on a factor V monoclonal antibody-Sepharose resin to isolate 35S-labeled factor V. The isolated material and 125I-factor V standards were analyzed by electrophoresis and autoradiography. The bioassay indicated an increase, with time, of unactivated factor V in the culture supernatant, whereas solubilized cells were negative for factor V. The radioimmunoassay indicated an increase, with time, of factor V antigen in the culture supernatants, and the solubilized cells yielded a constant level of antigen per cell. Autoradiograms of electrophoretograms of immunoadsorbed 35S-culture supernatant with 125I- factor V/Va standards revealed labeled proteins with electrophoretic mobilities compatible with 125I-factor V/Va standards. The data obtained from three different sources-bioassay, radioimmunoassay, and 35S-methionine incorporation-all indicate that factor V is synthesized by cultured bovine aortic endothelium.     

CFU-M-derived human megakaryocytes synthesize glycoproteins IIb and IIIa

Human megakaryocytes have been shown by immunofluorescent techniques to express platelet glycoprotein IIb/IIIa antigen. We report evidence that megakaryocytes derived from human committed megakaryocytic progenitor cells in vitro (CFU-M) synthesize glycoproteins IIb and IIIa. Nonadherent light-density human bone marrow cells were cultured in human plasma and methylcellulose using conditions that promote large megakaryocytic colonies. On day 13 the megakaryocytic colonies were picked, pooled, and pulsed with 35S-methionine in methionine-free media. Populations of approximately 100,000 cells with greater than or equal to 95% viability and containing 70% to 90% megakaryocytes were obtained reliably for study. After the radioactive pulse, the cell suspension was solubilized with nonionic detergent. To reduce nonspecific binding of 35S-labeled proteins to agarose, the lysate was chromatographed sequentially on glycine-quenched Affi-gel and antihuman factor X-Sepharose. The unbound material from these resins was then chromatographed on an antiglycoprotein IIb/IIIa monoclonal antibody resin (HP1-1D-Sepharose) or on a control monoclonal antibody resin. Bound fractions were eluted and analyzed by polyacrylamide gel electrophoresis and autoradiography. Autoradiograms of diethylamine eluates from HP1-1D-Sepharose revealed two labeled proteins with electrophoretic mobilities identical with those of human platelet membrane glycoproteins IIb and IIIa, isolated using similar conditions. Autoradiograms of material synthesized by control macrophages from the same donors revealed no significant labeling of proteins in the glycoprotein IIb/IIIa molecular weight range, nor were such proteins bound by HP1-1D-Sepharose. Our observations show that protein synthesis by CFU-M-derived human megakaryocytes can be readily studied using a small amount of bone marrow aspirate as starting material. This approach will allow the study of protein synthesis by megakaryocytes from normal subjects or from subjects with clinical disorders, and it will circumvent the need to obtain large amounts of bone marrow to prepare enriched populations of megakaryocytes.     

Prevalence of widespread pain and associations with work status: a population study

Background  

This population study based on a representative sample from a Swedish county investigates the prevalence, duration, and determinants of widespread pain (WSP) in the population using two constructs and estimates how WSP affects work status. In addition, this study investigates the prevalence of widespread pain and its relationship to pain intensity, gender, age, income, work status, citizenship, civil status, urban residence, and health care seeking.     

Trends in practice characteristics: analyses of 19 periodic surveys (1987-1992) of Fellows of the American Academy of Pediatrics

OBJECTIVE: To examine 6 years of practice characteristics data of Fellows of the American Academy of Pediatrics (AAP), focusing on sex differences for specialty area, primary activity, practice setting, and practice location. METHODS: We analyzed data from 19 Periodic Surveys that were fielded between 1987 and 1992. The Periodic Survey is used to survey AAP members regularly about current issues in pediatric practice. There are no duplicate respondents in these analyses of the first 19 Periodic Surveys. We collapsed the 19 surveys into the years in which they were fielded, and analyzed sex differences for each of the 6 years. In addition, we ran logistic regressions on several questions, including all 16 868 respondents, to examine how the characteristics of the specialty have been affected by the increase in the number of female pediatricians, controlling for survey year, age of respondents, and specialty area practiced. RESULTS: The proportion of nonresident AAP members who are female has grown throughout the 6 years; in 1987, 26.9% were female, and in 1992, 36.4% were female. For 5 of the 6 years there were sex differences in specialty area, usually concerning pediatric subspecialties. Substantial sex differences occurred in primary activity, in which each year women were more likely than men to be salaried. Men were more often in group practices, whereas women were generally more likely to practice in hospitals or clinics. Logistic regression demonstrated that there are sex differences in practice characteristics across time, but there is also a substantial change in practice characteristics accountable to survey year, eg, a pediatrician of either sex was 75% more likely to be salaried in 1992 than in 1987. CONCLUSIONS: Throughout the 6-year period, AAP members became increasingly more likely to practice general pediatrics, to be salaried, and to be younger-all effects independent of sex, all effects stronger for females. Rapid transformations in the health care system will likely reduce current sex differences in practice characteristics of the future.     

MIVACURIUM APNOEA: A TRAP FOR THE UNWARY

We present a case of unanticipated postoperative apnoea in a patient with associated medical illness to illustrate the diagnostic difficulty that can arise in the detection and subsequent management of mivacurium apnoea. A high index of suspicion is essential in the presence of concomitant medical conditions that may cause prolonged apnoea. To our knowledge, no report exists documenting the unanticipated occurrence of mivacurium apnoea in a patient with previously undiagnosed pseudoCholinesterase deficiency and concomitant medical illness who has previously undergone ‘balanced’ general anaesthesia.