Methods for producing T- and B-lymphocyte receptor-specific antisera.

Spent tissue culture medium from two continuous lymphoblastoid cell lines, FL-74 and CT45-S, expressing the T-lymphocyte receptor for guinea pig E and the B-lymphocyte receptor for EAC respectively were used to produce receptor-specific antisera. Anti-E receptor sera blocked E rosette formation on FL-74 cells, canine and feline lymphocytes and canine and feline thymocytes but not EAC rosette formation by CT45-S cells or canine and feline lymphocytes. Anti-EAC receptor sera blocked EAC rosette formation on CT45-S cells and canine or feline lymphocytes. Absorption of antisera will the appropriate lymphoblastoid cell line removed E or EAC-blocking activity. The results of this study suggest that similar methods may be used to produce lymphocyte subpopulation-specific antisera in other species including man.     

Effect of clarithromycin on cytokines and chemokines in children with an acute exacerbation of recurrent wheezing: a double-blind, randomized, placebo-controlled trial.

BACKGROUND: Clarithromycin is postulated to possess immunomodulatory properties in addition to its antimicrobial activity. OBJECTIVE: To evaluate the effect of clarithromycin on serum and nasopharyngeal cytokine and chemokine concentrations in children with an acute exacerbation of recurrent wheezing. METHODS: Children with a history of recurrent wheezing or asthma and who presented with an acute exacerbation of wheezing were enrolled in a double-blind, randomized trial of clarithromycin vs placebo. Concentrations of tumor necrosis factor alpha (TNF-alpha), interferon-gamma (IFN-gamma), interleukin-1beta (IL-1beta), IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, granulocyte-macrophage colony-stimulating factor, RANTES, eotaxin, macrophage inflammatory protein 1alpha, macrophage inflammatory protein 1beta, and monocyte chemoattractant protein 1 were measured in serum and/or nasopharyngeal aspirates before, during, and after therapy. Mycoplasma pneumoniae and Chlamydophila pneumoniae infection were evaluated for by polymerase chain reaction and serologic testing. RESULTS: Nasopharyngeal concentrations of TNF-alpha, IL-1beta, and IL-10 were significantly and persistently lower in children treated with clarithromycin compared with placebo. There tended to be a greater effect of clarithromycin on nasopharyngeal cytokine concentrations in patients with evidence of M. pneumoniae or C. pneumoniae infection. No significant differences were detected in serum cytokines for children treated with clarithromycin compared with placebo. CONCLUSION: Clarithromycin therapy reduces mucosal TNF-alpha, IL-1beta, and IL-10 concentrations in children with an acute exacerbation of recurrent wheezing.     

Rabies virus glycoprotein pseudotyping of lentiviral vectors enables retrograde axonal transport and access to the nervous system after peripheral delivery

In this report it is demonstrated for the first time that rabies-G envelope of the rabies virus is sufficient to confer retrograde axonal transport to a heterologous virus/vector. After delivery of rabies-G pseudotyped equine infectious anaemia virus (EIAV) based vectors encoding a marker gene to the rat striatum, neurons in regions distal from but projecting to the injection site, such as the dopaminergic neurons of the substantia nigra pars compacta, become transduced. This retrograde transport to appropriate distal neurons was also demonstrated after delivery to substantia nigra, hippocampus and spinal cord and did not occur when vesicular stomatitis virus glycoprotein (VSV-G) pseudotyped vectors were delivered to these sites. In addition, peripheral administration of rabies-G pseudotyped vectors to the rat gastrocnemius muscle leads to gene transfer in motoneurons of lumbar spinal cord. In contrast the same vector pseudotyped with VSV-G transduced muscle cells surrounding the injection site, but did not result in expression in any cells in the spinal cord. Long-term expression was observed after gene transfer in the nervous system and a minimal immune response which, together with the possibility of non-invasive administration, greatly extends the utility of lentiviral vectors for gene therapy of human neurological disease.     

Diurnal variations of serum erythropoietin at sea level and altitude

This study tested the hypothesis that the diurnal variations of serum-erythropoietin concentration (serum-EPO) observed in normoxia also exist in hypoxia. The study also attempted to investigate the regulation of EPO production during sustained hypoxia. Nine subjects were investigated at sea level and during 4 days at an altitude of 4350 m. Median sea level serum-EPO concentration was 6 (range 6–13) U·l^–1. Serum-EPO concentration increased after 18 and 42 h at altitude, [58 (range 39–240) and 54 (range 36–340) U·l^–1, respectively], and then decreased after 64 and 88 h at altitude [34 (range 18–290) and 31 (range 17–104) U·l^–1, respectively]. These changes of serum-EPO concentration were correlated to the changes in arterial blood oxygen saturation (r = –0.60,P = 0.0009), pH (r = 0.67,P = 0.003), and in-vivo venous blood oxygen half saturation tension (r = –0.68,P = 0.004) but not to the changes in 2, 3 diphosphoglycerate. After 64 h at altitude, six of the nine subjects had down-regulated their serum-EPO concentrations so that median values were three times above those at sea level. These six subjects had significant diurnal variations of serum-EPO concentration at sea level; the nadir occurred between 0800–1600 hours [6 (range 4–13) U·l^–1], and peak concentrations occurred at 0400 hours [9 (range 8–14) U·l^–1,P = 0.02]. After 64 h at altitude, the subjects had significant diurnal variations of serum-EPO concentration; the nadir occurred at 1600 hours [20 (range 16–26) U·l^–1], and peak concentrations occurred at 0400 hours [31 (range 20–38) U·l^–1,P = 0.02]. This study demonstrated diurnal variations of serum-EPO concentration in normoxia and hypoxia, with comparable time courses of median values. The results also suggested that EPO production at altitude is influenced by changes in pH and haemoglobin oxygen affinity.     

Cell division and deoxyribonucleic acid (DNA) synthesis in cultures of stimulated lymphocytes.

The responses of lymphocytes cultured with various stimulants were analysed with respect to DNA synthesis and cell division. Autoradiographic labelling with [3H]thymidine indicated that similar proportions of cells had incorporated this labelled precursor for DNA synthesis during both short and long periods of exposure to this specific precursor for DNA synthesis. Changes in labelling index (LI) after pulsing these cells with [3H]thymidine showed that exchange of labelled material, which could not be chased out with unlabelled thymidine, was responsible for the increases of LI seen. Failure to prevent this increase with excess unlabelled thymidine indicated that direct incorporation of [3H]thymidine did not account for this exchange. Using hydroxyurea and colcemid arrest to analyse cell cycle events in these cultures, it was shown that approximately 70 per cent of the responding cells in cultures of stimulated lymphocytes, while actively synthesizing DNA, were not in cell cycle for division. It was concluded that DNA turnover, involving synthesis and exchange of newly synthesized material, possibly DNA, was occurring in these cells.     

Pediatric circulatory support systems

Ventricular assist devices (VADs) are a valid option for long term circulatory support in pediatric patients with postoperative myocardial failure or debilitating heart defects. Most clinical experience to date has involved the short-term support of patients weighing 6 kg and larger. For cases of VAD implementation in pediatric patients, the assist device showed tremendous promise in reversing cardiac failure and providing adequate support as a bridge to cardiac transplantation. The Medos-HIA system, Berlin Heart, Medtronic Bio-Medicus Pump, Abiomed BVS 5000, Toyobo-Zeon pumps, and Hemopumps have proven successful for short-term circulatory support for the pediatric population. The Jarvik 2000 and Pierce-Donachy pediatric system further demonstrate the potential to be used for pediatric circulatory support. The clinical and experimental success of these support systems provide encouragement to believe that long-term support is possible.     

Quantitative comparison of intestinal invasion of zoonotic serotypes of Salmonella enterica in poultry

The aim of the present study was to compare the invasion of selected zoonotic Salmonella serotypes of poultry in an in vivo chicken intestinal loop model and also in vitro in epithelial cell cultures. Invasion was measured relative to a reference strain, Salmonella Typhimurium 4/74 inv H201::Tn phoA . Two serotypes demonstrated intracellular log 10 counts that differed significantly from all other serotypes tested: Salmonella Enteritidis PT4 being 1.5 log 10 colony forming units (CFU) (31-fold) higher, and Salmonella Tennessee being 0.7 log 10 CFU (fivefold) lower than the reference strain ( P h 0.0001). A group of serotypes, which can be vertically transmitted, showed significantly higher intracellular counts (fourfold to eightfold) than the reference strain. The group included S. Typhimurium 4/74, S. Typhimurium DT104 (poultry and porcine isolates), S. Enteritidis PT1, S. Enteritidis PT6, S. Enteritidis PT8, and Salmonella Berta. The serotypes Salmonella Hadar, Salmonella Virchow, S. 4,12:b:-, S. Typhimurium DT41, and Salmonella Infantis, most of which are considered horizontally transmitted, did not show significantly different intracellular counts from the reference strain. Results from the cell culture invasion studies agreed with the in vivo data, with the exception of S. Berta and the poultry isolate of S. Typhimurium DT104.     

Clear relationship between ETF/ETFDH genotype and phenotype in patients with multiple acyl-CoA dehydrogenation deficiency

Mutations in electron transfer flavoprotein (ETF) and its dehydrogenase (ETFDH) are the molecular basis of multiple acyl-CoA dehydrogenation deficiency (MADD), an autosomal recessively inherited and clinically heterogeneous disease that has been divided into three clinical forms: a neonatal-onset form with congenital anomalies (type I), a neonatal-onset form without congenital anomalies (type II), and a late-onset form (type III). To examine whether these different clinical forms could be explained by different ETF/ETFDH mutations that result in different levels of residual ETF/ETFDH enzyme activity, we have investigated the molecular genetic basis for disease development in nine patients representing the phenotypic spectrum of MADD. We report the genomic structures of the ETFA, ETFB, and ETFDH genes and the identification and characterization of seven novel and three previously reported disease-causing mutations. Our molecular genetic investigations of these nine patients are consistent with three clinical forms of MADD showing a clear relationship between the nature of the mutations and the severity of disease. Interestingly, our data suggest that homozygosity for two null mutations causes fetal development of congenital anomalies resulting in a type I disease phenotype. Even minute amounts of residual ETF/ETFDH activity seem to be sufficient to prevent embryonic development of congenital anomalies giving rise to type II disease. Overexpression studies of an ETFB-D128N missense mutation identified in a patient with type III disease showed that the residual activity of the mutant enzyme could be rescued up to 59% of that of wild-type activity when ETFB-D128N-transformed E. coli cells were grown at low temperature. This indicates that the effect of the ETF/ETFDH genotype in patients with milder forms of MADD, in whom residual enzyme activity allows modulation of the enzymatic phenotype, may be influenced by environmental factors like cellular temperature.