Expression of the leukocyte functional molecule (LFA-1) on mouse platelets

Platelet involvement in adhesion, hemostasis, and immune adherence is mediated by functionally associated cell surface molecules. Platelets are also involved in cytolytic reactions, but little is known about the mechanisms or biologic significance of these processes. To further investigate cell surface molecules concerned with platelet function, antisera against mouse platelets, thymocytes, and macrophages and monoclonal antibodies against Mac-1 (complement receptor type 3) and leukocyte function-associated glycoprotein type 1 (LFA-1) were used to demonstrate LFA-1--like molecules on mouse platelets. The alpha subunits of platelet and thymocyte LFA-1 showed identical electrophoretic mobility but differed significantly from the alpha subunit of macrophage Mac-1. Peptide mapping demonstrated the identity of the beta subunits of these three molecules but showed that the alpha subunit of Mac-1 was distinct from the alpha subunits of platelet and thymocyte LFA-1. Platelet LFA-1, as demonstrated by surface iodination with lactoperoxidase and by labeling sialic acid residues with sodium borohydride, was not a major component of the platelet membrane. The functional significance of LFA-1 on mouse platelets has yet to be demonstrated, monoclonal antibodies against LFA-1 having little effect on adenosine diphosphate-induced platelet aggregation and immune adherence. In contrast, although Mac-1 could not be demonstrated on mouse platelets in immunoprecipitation studies, its presence was clearly demonstrated by low levels of antibody binding in enzyme-linked immunosorbent assays and by the ability of M1/70 monoclonal antibody to inhibit platelet immune adherence. Human platelets, which are inactive in immune adherence assays, are shown to lack LFA-1 and Mac-1.     

A single dose of granulocyte-macrophage colony-stimulating factor induces systemic interleukin-8 release and neutrophil activation in healthy volunteers

Granulocyte-macrophage colony-stimulating factor (GM-CSF) and granulocyte colony-stimulating factor (G-CSF) are frequently used in the clinical management of neutropenia. These cytokines not only enhance the proliferation of myeloid precursor cells but also influence the function of mature leukocytes. In a previous study, we found that the in vivo effects of G-CSF on neutrophils differed from those in vitro. In the present study, we investigated the effects of a single dose of recombinant GM-CSF (7.5 microg/kg, subcutaneously) on neutrophils, eosinophils, and monocytes in healthy volunteers. We analyzed leukocyte kinetics, phenotypical changes, neutrophil degranulation, and systemic cytokine production. After GM-CSF injection, phenotypical changes included upregulation of CD11b on all three cell types and a decreased expression of L-selectin and Fc(gamma)RIII on neutrophils. Neutrophil degranulation was evident from the increased plasma concentrations of lactoferrin and elastase. GM-CSF induced the release of interleukin-8 (IL-8), but not of IL-6 or tumor necrosis factor alpha. In comparison to the results from our previous study with G-CSF in healthy volunteers, GM-CSF induced a stronger activation of mature neutrophils but had a much less pronounced effect on the production and maturation of neutrophil precursors. These data may help to guide the choice between the two cytokines in different clinical situations.     

Prioritisation of patients on waiting lists for hip and knee arthroplasties and cataract surgery: Instruments validation

Background  

Prioritisation instruments were developed for patients on waiting list for hip and knee arthroplasties (AI) and cataract surgery (CI). The aim of the study was to assess their convergent and discriminant validity and inter-observer reliability.     

Percutaneous cholecystolithotomy: preliminary experience and technical considerations

Surgical cholecystectomy is associated with a high morbidity and mortality in elderly patients with acute calculous cholecystitis and underlying cardiac or pulmonary disease. Currently there are few alternatives for treating these patients. The authors have used percutaneous cholecystolithotomy in 11 such high-risk patients for definitive treatment of gallbladder calculi. In all 11 patients all stones were successfully removed from the gallbladder and cystic duct. The entire procedure--from initial tube placement to final tube removal--lasted 17-40 days (mean, 21 days). There were two complications: one minor--local wound infection--and one major--bile peritonitis with eventual death. Percutaneous cholecystolithotomy is an effective alternative therapy for acute calculous cholecystitis in elderly, debilitated patients.     

Reversal of tubal sterilization using laparoscopically placed titanium staples: preliminary experience

We tested the feasibility of performing outpatient laparoscopic surgery to reverse tubal sterilization using titanium staples to reapproximate the oviducts. A total of 14 women underwent the procedure which involved excision of the tubal eschar, stenting of the severed remnants, and circumferential stapling of the muscularis and serosa. Reapproximation was possible in all cases, with a measured tubal length post-anastomosis of 4.5 +/- 0.5 cm (range 3.0-7.0 cm). The length of operating time was 2.8 +/- 0.2 h (range 2.2-3.8 h), and all patients were discharged the same day. There were no operative complications, and no readmissions were necessary. Within 6 months of surgery there were six pregnancies including one spontaneous abortion and five ongoing pregnancies. Of those not conceiving within 8 months, seven (100%) demonstrated tubal patency on a follow-up hysterosalpingogram. We conclude the laparoscopic approach to tubal sterilization reversal is a viable alternative to open abdominal microsurgical approaches. Although preliminary, laparoscopic surgery promises to be cost effective, as it can be performed on an outpatient basis, may reduce operative time and minimizes the recuperative period of patients.      

Cumulative conception and live birth rates after oocyte donation: implications regarding endometrial receptivity

The purpose of the present study was to determine the cumulative likelihood of pregnancy success after repetitive cycles of oocyte donation and specifically to examine the influence of recipient age and diagnosis upon the cumulative likelihood of pregnancy in an effort to identify any potential subgroup of recipients who might have diminished endometrial receptivity. We retrospectively analysed the outcome of 418 consecutive embryo transfer cycles among 276 recipients of oocyte donation in our institution. We analysed clinical pregnancy and delivery rates in the recipients divided by age groups and diagnostic groups. For the purpose of life-table analysis, only cycles prior to and including the first cycle producing a successful pregnancy were included. Frozen-thawed embryo transfers were not included in the analysis. The overall clinical pregnancy rate was 36.2% (95% CI 31-41%) and the cumulative pregnancy rate after four cycles was 87.9%. The overall delivery rate was 29.3% (95% CI 25-33%) and the cumulative delivery rate after four cycles was 86.1%. There were no statistically significant differences in any of the rates attributable to recipient age or diagnosis. No decline in per cycle success was noted over consecutive cycles. We conclude that neither recipient age nor diagnosis plays a substantial role in the success of oocyte donation, implying that endometrial receptivity is unaltered by age or diagnosis. Furthermore, up to four successive cycles of oocyte donation are associated with the same probability of success.      

Concurrent comparison of the safety of paid cytapheresis and volunteer whole-blood donors

BACKGROUND: Historically, paid blood donors were found to transmit hepatitis at higher rates than volunteers. In those older studies, paid donors frequently were recruited from prisons or slum areas–a finding consistent with the belief that monetary payment in itself did not necessarily lead to the high-risk status of commercial blood. Instead, it was the population base from which the donors were recruited that was important. STUDY DESIGN AND METHODS: Today, cytapheresis donors are in great demand. Because payment is one incentive that might entice donors to undertake the increased commitment of repeated cytapheresis donation, the results were studied of infectious disease history and laboratory testing performed concurrently in 917 volunteer whole-blood donors and 1240 paid cytapheresis donors, who were enrolled in distinct programs at the DeGowin Blood Center from October 7, 1987, through November 30, 1990. RESULTS: When first, repeat, and overall donations made by these donors were evaluated separately, paid cytapheresis donors were found to exhibit no increase in infectious disease history or test results beyond those of volunteer whole-blood donors. CONCLUSION: Thus, paid cytapheresis donors, when managed within a formal program, should not necessarily be presumed to be more dangerous than volunteers, from an infectious disease aspect. However, definitive proof of safety (comparison of transfusion-transmitted infection rates in two groups of patients receiving blood components exclusively from either paid cytapheresis or volunteer donors) was not pursued by long- term follow-up studies.