Release of soluble transferrin receptor from the surface of human leukemic HL60 cells

Information regarding transferrin (Tf) receptor degradation is largely incomplete. HL60 cells were shown to release to their growth medium a Tf-binding protein which could be immunoprecipitated by anti-Tf receptor monoclonal antibodies (MoAbs) B3/25 and OKT9. Soluble Tf receptor was detected in the medium within one hour of replating of cells, and its release was inhibited at 4 degrees C. The affinity of Tf for the soluble receptor released by cells (kd = 2.3 x 10(-10) mol/L) was slightly lower than its affinity for the detergent-solubilized cellular receptor (kd = 1.2 x 10(-10) mol/L). 125I-Tf internalized and released by cells subsequently bound to Tf receptor released by the same cells, and soluble Tf receptor in the conditioned medium (CM) inhibited 125I-Tf binding to intact cells. The soluble Tf receptor isolated from the CM was smaller (78,000 daltons) than the cell surface receptor (94,000 daltons) when analyzed by gel electrophoresis under reducing conditions. Isolated cell membranes readily released soluble receptor; however, this release could be blocked by protease inhibitors. The soluble Tf receptor may represent the extracytoplasmic domain of the cellular Tf receptor released from the surface of HL60 cells through proteolytic cleavage by a membrane-based protease.     

Clinical Impact of Community-Acquired Respiratory Viruses on Bronchiolitis Obliterans After Lung Transplant

Community-acquired viral respiratory tract infections (RTI) in lung transplant recipients may have a high rate of progression to pneumonia and can be a trigger for immunologically mediated detrimental effects on lung function. A cohort of 100 patients was enrolled from 2001 to 2003 in which 50 patients had clinically diagnosed viral RTI and 50 were asymptomatic. All patients had nasopharyngeal and throat swabs taken for respiratory virus antigen detection, culture and RT-PCR. All patients had pulmonary function tests at regular intervals for 12 months. Rates of rejection, decline in forced expiratory volume (L) in 1 s (FEV-1) and bacterial and fungal superinfection were compared at the 3-month primary endpoint. In the 50 patients with RTI, a microbial etiology was identified in 33 of 50 (66%) and included rhinovirus (9), coronavirus (8), RSV (6), influenza A (5), parainfluenza (4) and human metapneumovirus (1). During the 3-month primary endpoint, 8 of 50 (16%) RTI patients had acute rejection versus 0 of 50 non-RTI patients (p=0.006). The number of patients experiencing a 20% or more decline in FEV-1 by 3 months was 9 of 50 (18%) RTI versus 0 of 50 non-RTI (0%) (p=0.003). In six of these nine patients, the decline in FEV-1 was sustained over a 1-year period consistent with bronchiolitis obliterans syndrome (BOS). Community-acquired respiratory viruses may be associated with the development of acute rejection and BOS.     

Localization of a gene for otosclerosis to chromosome 15q25-q26

Among white adults otosclerosis is the single most common cause of hearing impairment. Although the genetics of this disease are controversial, the majority of studies indicate autosomal dominant inheritance with reduced penetrance. We studied a large multi- generational family in which otosclerosis has been inherited in an autosomal dominant pattern. Five of16 affected persons have surgically confirmed otosclerosis; the remaining nine have a conductive hearing loss but have not undergone corrective surgery. To locate the disease- causing gene we completed genetic linkage analysis using short tandem repeat polymorphisms (STRPs) distributed over the entire genome. Multipoint linkage analysis showed that only one genomic region, on chromosome 15q, generated a lod score >2.0. Additional STRPs were typed in this area, resulting in a lod score of 3.4. STRPs FES (centromeric) and D15S657 (telomeric) flank the 14. 5 cM region that contains an otosclerosis gene.      

Peritoneal fluid concentrations of interleukin-8 in women with endometriosis: relationship to stage of disease

There is increasing evidence that immunological mechanisms play a role in the pathogenesis and pathophysiology of endometriosis. It was therefore of interest to study interleukin-8 (IL-8), a chemokine, in the peritoneal fluid and peripheral blood of women undergoing laparoscopic procedures. The presence and concentrations of IL-8 in relation to endometriosis, infertility and abdominal pain were evaluated. Samples of peritoneal fluid (n = 49) and peripheral blood (n = 50) were obtained from 50 consecutive patients undergoing laparoscopic surgery for various gynaecological indications (abdominal pain, infertility, sterilization). IL-8 was present in the peritoneal fluid of most women (87%). The concentration of IL-8 in the peritoneal fluid was higher in women with endometriosis compared to women without (P = 0.02). This difference was more pronounced in early (stage 1) endometriosis (P = 0.001). IL-8 concentrations in the peritoneal fluid were also higher in women with early endometriosis compared to women with later stages of the disease (P = 0.003). Peripheral blood concentrations did not correlate with peritoneal fluid concentrations of IL-8 and/or the presence of endometriosis. We conclude that IL-8 is an important factor that may contribute to the pathogenesis of endometriosis possibly by promoting neovascularization. This information can be a guide in the development of new therapeutic approaches for the treatment of endometriosis.      

Rapid, sensitive, competitive serologic enzyme-linked immunosorbent assay for detecting serum antibodies to bovine herpesvirus type 1.

An enzyme-linked immunosorbent assay (ELISA) for the detection of cattle antibodies to bovine herpesvirus type 1 was developed on the basis of competition between serum antibody and a virus-neutralizing mouse monoclonal antibody. The assay showed improved sensitivity over the virus neutralization (VN) test and over an enhanced VN test in which incubation of antibody-virus mixtures was carried out for 24 h. With the ELISA, antibodies in sera from experimentally infected cattle were detected earlier after infection and showed more rapid increases in levels. A comparison of the ELISA with the VN tests by using a set of 85 field sera with low levels of antibodies demonstrated that the ELISA was the most sensitive test, detecting 10 positive serum samples that were negative by the VN tests. The ELISA was inexpensive, rapid, and highly reproducible and showed a significant improvement in sensitivity over VN tests.     

Evaluation of the Anaerobe-Tek system for identification of anaerobic bacteria.

The Anaerobe-Tek system of Flow Laboratories, Inc. (McLean, Va.), is a new bacterial identification system which uses Gram morphology, sporulation, and reactions from 15 agar-based biochemical tests to generate a six-digit code number for identification of anaerobic bacteria. Supplemental tests are recommended when necessary to complete species identification. Individual test and identification performance of this system was evaluated by testing 216 anaerobic bacteria representing 31 species and one Centers for Disease Control unnamed group in parallel with a routine clinical laboratory identification system. Most of the tests in the Anaerobe-Tek system performed well; 85% of the organisms were correctly identified. The 32 (15%) failures in identification were due to omission from the identification code data base (38%), false-negative indole reactions (22%), and other incorrect biochemical reactions (40%). The replacement of the recommended indole test with an extraction method using the inoculum broth and an expansion of the data base of the system could raise the correct identification for this organism population to over 90% with no change in the test materials.     

Occurrence of Staphylococcus lugdunensis in consecutive clinical cultures and relationship of isolation to infection.

Consecutive record review over a 63-month period revealed 229 Staphylococcus lugdunensis isolates, or 10.1% of the staphylococcal species that were not Staphylococcus aureus or Staphylococcus epidermidis. A total of 155 S. lugdunensis specimens were isolated from sites over the entire bodies of the 143 patients studied. The most common clinical diagnoses were skin and skin structure infections (55.4%) and blood and vascular catheter infections (17.4%). For 40% of the reviewed specimens, S. lugdunensis was the sole agent isolated, and for 60% of specimens, S. lugdunensis was isolated as part of mixed flora. In only 15.4% of clinically reviewed specimens was S. lugdunensis clearly a culture contaminant or colonizing organism. The pattern of human infection identified in this study emphasizes the predominance of skin and soft tissue S. lugdunensis infections over deep serious infections such as endocarditis, peritonitis, infected hip prosthesis, and osteomyelitis and vascular-associated infections. S. lugdunensis should be included along with S. epidermidis, Staphylococcus haemolyticus, and Staphylococcus saprophyticus as a coagulase-negative species of Staphylococcus pathogenic for humans.