The rate of torque development: a unique, non-invasive indicator of eccentric-induced muscle damage?

This study examined the time courses of recovery for isometric peak torque and rate of torque development (RTD) after eccentric-induced muscle damage. 18 men completed 6 sets of 10 maximal eccentric isokinetic muscle actions at 30° · s(-1). Peak torque, peak RTD and RTD at 10 (RTD10), 50 (RTD50), 100 (RTD100) and 200 ms (RTD200), serum creatine kinase and lactate dehydrogenase were measured before (PRE), immediately after (POST), 24, 48 and 72 h after eccentric exercise. Creatine kinase and lactate dehydrogenase increased from 139 to 6 457 and from 116 to 199 IU · L(-1) from PRE to 72 h, respectively. Peak torque and all RTDs decreased at POST. Peak torque and RTD200 remained lower than PRE through 72 h. Peak RTD remained lower than PRE through 48 h, but was not different from PRE at 72 h. RTD10 and RTD100 were lower than PRE through 24 h, but were not different from PRE at 48 and 72 h. RTD50 decreased at POST, but was not different from PRE at 24 h. Early phase RTDs recovered more quickly than PT and RTD200. Early phase RTDs may reflect neural mechanisms underlying eccentric-induced force decrements, while late RTDs may describe the same physiological mechanisms as PT.

GB virus C (GBV-C/HGV) and E2 antibodies in children preliver and postliver transplant.

The association of GB virus type C (GBV-C) virus and clinical disease is uncertain. The role of GBV-C and (Envelope) E2 antibody in children with liver transplants has not been determined. This study's aim is to examine the prevalence of GBV-C in children with liver transplants, to assess the relationship of GBV-C to posttransplant hepatitis, and to determine the role of E2 antibodies. Sera from 34 children, preliver and postliver transplant, between 1989-1996 were tested for GBV-C (Ribonucleic acid) RNA by the automated Abbott LCx PCR assay. Anti-E2 antibodies were detected by an Abbott immunoassay. Recent posttransplant liver biopsies were examined for hepatitis. The results of the study determined that pretransplant, four children (12%) were GBV-C RNA positive. Posttransplant, 14 (42%) children were GBV-C RNA positive. The GBV-C RNA positive conversion rate was 33% (CI 17.2-55.7%). Patients received blood products from a mean of 68 +/- 34 donors, which correlated with GBV-C acquisition. There was no difference in the incidence (32%versus 36%; p = 0.726) or severity (grade 2.00 versus 0.68; p = 0.126) of posttransplant hepatitis in the liver biopsies of GBV-C RNA negative and/or positive children, respectively. Pretransplant, nine of 32 children were anti-E2 positive. Posttransplant, eight of 32 children were anti-E2 positive, including five children who were anti-E2 positive pretransplant. Of nine children who were anti-E2 positive and GBV-C RNA negative pretransplant, three became GBV-C RNA positive posttransplant. The results of this study conclude that the prevalence of GBV-C infection in children postliver transplantation is high and that blood product transfusions correlate with GBV-C acquisition. Also, no correlation was found between GBV-C RNA and the incidence or severity of posttransplant hepatitis. Finally, E2 antibody presence before transplantation failed to provide complete protection from GBV-C acquisition.

Detection of GB virus C by the RT-PCR LCx system.

The recent publication of representative genomic sequences of GBV-C has permitted the selection of PCR primers for detection of GBV-C in clinical samples by PCR techniques. Traditional amplification methodologies which couple reverse transcription polymerase chain reaction (RT-PCR) and Southern blot detection are slow, cumbersome, and can be technique dependent. This has hampered studies to determine the clinical significance of GBV-C. We report the selection of highly conserved PCR primers and a probe useful for semi-automated RT-PCR using the Abbott LCx system. This adaptation of the LCx system expands its capabilities to include the detection of RNA by RT-PCR, in addition to DNA detection by ligase chain reaction (LCR).

A multicenter study to evaluate a novel assay for quantitation of soluble interleukin 2 receptor in renal transplant recipients.

The clinical utility of monitoring soluble interleukin 2 receptor (sIL-2R) as an indicator of immune stimulation in renal transplant patients was evaluated in a retrospective study at 3 centers. Serum samples (n = 2360) were obtained from 86 (17 living related donor, 69 cadaver) transplant recipients. The patients had received either triple therapy (n = 35) or antilymphocyte antibody induction therapy followed by triple therapy (n = 51). The mean period of postoperative observation was 118 days (range, 6-349 days). Serum sIL-2R concentrations were quantitated by an automated microparticle enzyme immunoassay (MEIA) (Abbott Diagnostics) in which sIL-2R was captured by 7G7/B6 monoclonal antibody-coated microparticles and detected by an immunospecific rabbit antihuman sIL-2R-alkaline phosphatase conjugate. A distinct advantage of the technique was rapid turn-around time: 1-24 results were obtained in less than 50 min. Cyclosporine trough concentrations were determined by radioimmunoassay or high-performance liquid chromatography. Diagnosis of rejection was established by clinical and histological criteria. The mean sIL-2R concentration in patients receiving antilymphocyte antibody induction therapy increased from 3486 +/- 1729 U/ml (+/- SD) at the time of transplant to a maximum of 7395 +/- 7101 U/ml on the third day posttransplant; this increase was not observed in patients receiving triple therapy (P less than 0.0001). By the sixth day of posttransplant, there were no differences in sIL-2R levels in the two groups. Fifty rejection episodes were observed in 29 patients on triple therapy. The mean sIL-2R concentration rose from 3022 U/ml at the data point prior to rejection to 3524 U/ml at the time of rejection. Thirty-four rejection episodes were observed in 26 patients receiving induction therapy. The mean sIL-2R concentration was 3015 U/ml at the data point prior to rejection and 4815 U/ml at the time of rejection. The sIL-2R concentrations began increasing earlier and rose higher in rejecting patients who received induction therapy than in those receiving triple therapy. Early posttransplant sIL-2R levels increased significantly more in cadaver recipients than in LRD recipients, reaching a maximum on day 2 posttransplant (P less than 0.001). Prerejection sIL-2R concentrations were significantly lower in LRD recipients than in cadaver recipients (2248 U/ml vs. 4290 U/ml, P less than 0.02), as were sIL-2R levels at the time of diagnosis of rejection (2800 U/ml vs. 4832 U/ml, P = 0.01). The mean sIL-2R level in stable long-term graft recipients was 2110 U/ml, with approximately 90% of values less than 3000 U/ml.(ABSTRACT TRUNCATED AT 400 WORDS)

RETROCELL HIV-1 passive hemagglutination assay for HIV-1 antibody screening.

A passive hemagglutination assay (PHA) for serum human immunodeficiency virus type 1 (HIV-1) antibody screening was developed using aldehyde-stabilized human erythrocytes coated with purified HIV-1 antigens. The assay is simple to perform, and the components are inexpensive. In preliminary testing of a panel of 490 confirmed HIV-1 seropositive specimens, all tested positive by the HIV-1 PHA assay. By testing seroconversion specimens and dilution panels, the assay demonstrated a sensitivity equivalent to a recombinant protein-based HIV-1 enzyme immunoassay (EIA). In-house evaluation of 2,557 HIV-1 prescreened specimens from South African blood bank donors revealed initial and repeat reactive rates of 0.2 and 0.04%, respectively. Field testing of the HIV-1 antibody PHA at two sites gave performance of 100% sensitivity (400 seroconfirmed samples) and 0.55% initial/0.28% repeat reactive rates in the testing of 3,983 negative samples. The performance, low cost, and ease of use make the HIV-1 antibody PHA test a prime candidate for HIV-1 antibody screening in regions of the world where more sophisticated technology is inappropriate.