Effect of cystic fibrosis-associated mutations in the fourth intracellular loop of cystic fibrosis transmembrane conductance regulator

The cystic fibrosis transmembrane conductance regulator (CFTR) contains multiple membrane spanning sequences that form a Cl- channel pore and cytosolic domains that control the opening and closing of the channel. The fourth intracellular loop (ICL4), which connects the tenth and eleventh transmembrane spans, has a primary sequence that is highly conserved across species, is the site of a preserved sequence motif in the ABC transporter family, and contains a relatively large number of missense mutations associated with cystic fibrosis (CF). To investigate the role of ICL4 in CFTR function and to learn how CF mutations in this region disrupt function, we studied several CF-associated ICL4 mutants. We found that most ICL4 mutants disrupted the biosynthetic processing of CFTR, although not as severely as the most common DeltaF508 mutation. The mutations had no discernible effect on the channel's pore properties; but some altered gating behavior, the response to increasing concentrations of ATP, and stimulation in response to pyrophosphate. These effects on activity were similar to those observed with mutations in the nucleotide-binding domains, suggesting that ICL4 might help couple activity of the nucleotide-binding domains to gating of the Cl- channel pore. The data also explain how these mutations cause a loss of CFTR function and suggest that some patients with mutations in ICL4 may have a milder clinical phenotype because they retain partial activity of CFTR at the cell membrane.     

Experimental study of therapeutical properties and safety of king crab collagenase-containing ointment

The effects of ointment containing king crab (Paralithodes camtschatica) collagenase on intact skin, thermal, and pyonecrotic wounds were studied in rats by using hematological, biochemical, immunological, and morphological methods. The ointment for the skin and viscera was shown to be safe. It is highly effective in debriding the infected wounds. Different concentrations of collagenase were tested. The concentration of collagenase was recommended to be 0.2 mg/g ointment for use.     

Promotion of ulcerative duodenitis in young ferrets by oral immunization with Helicobacter mustelae and muramyl dipeptide

BACKGROUND: The purpose of this study was to determine whether oral immunization of ferret kits with a whole-cell sonicate of Helicobacter mustelae lysate (Hml) and the adjuvant muramyl dipeptide (MDP) would reduce the incidence of natural colonization with H. mustelae and the extent of Helicobacter-associated gastritis by enhancing the host mucosal immune response. MATERIALS AND METHODS: Between the ages of 4 and 11 weeks, 44 ferret kits were gavaged with Hml and various doses of MDP. The extent of gastritis and duodenitis and the immune response to H. mustelae were evaluated. RESULTS: All kits became colonized naturally with H. mustelae and the majority developed mild to severe gastritis and duodenitis. Kits that received Hml with MDP developed significantly greater inflammation of the gastric antrum and duodenum, as compared to kits vaccinated with Hml alone. Vaccination with Hml and 50 micrograms of MDP was associated with severe lesions in the proximal duodenum characterized by accumulation of mononuclear inflammatory cells, mucosal erosion, and ulceration. Although serum antibody specific for H. mustelae in 4-week-old kits was approximately 50% of adult levels, a finding attributable to passively acquired maternal antibody, both systemic and mucosal antibody levels became depressed over time despite oral vaccination. The humoral immune response was sufficiently low to prevent detection of any significant dose effect of MDP on antibody levels among experimental groups. CONCLUSIONS: Oral vaccination of young ferrets with Hml and 50 micrograms MDP increased the risk of Helicobacter-associated mucosal ulceration in the proximal duodenum, which was associated with low humoral (but significant cell-mediated) immune responses to H. mustelae. In retrospect, the frequency of vaccination may have suppressed the systemic humoral immune response, thereby promoting mucosal damage by H. mustelae. The 50-microgram dose of MDP enhanced the cell-mediated immune response, which indirectly contributed to development of severe lesions. The increased frequency of mucosal damage associated with this vaccination regimen enhances the value of the ferret model for studying duodenal ulceration secondary to Helicobacter infection.     

Acute rejection of marrow grafts in patients transplanted from a partially mismatched related donor: clinical and immunologic characteristics

Bone marrow transplantation (BMT) from a partially mismatched related donor (PMRD) provides a treatment option for patients lacking a matched sibling donor. T lymphocyte depletion of the graft reduces the risk of severe graft-versus-host disease, but may increase the risk of graft failure. We evaluated the pattern of acute graft rejection in eight patients receiving PMRD BMT with respect to the conditioning therapy, diagnosis, age and sex of donor and recipient, degree of HLA mismatch, and peripheral blood immunophenotype at the time of graft failure. All grafts were partially depleted of T lymphocytes. Marrow grafts infused into patients who experienced acute rejection did not differ significantly in nucleated cell dose, degree of T lymphocyte depletion, T cell dose, or CFU-GM/kg infused, from those received by 31 patients who showed durable engraftment. In three of four patients who rejected their grafts, and had sufficient peripheral blood cells for immunophenotyping, a CD3+CD8+ T lymphocyte phenotype was predominant at the time of acute rejection. In one patient rejection was associated with a predominant population of CD3+CD4+ T lymphocytes. Rejection was significantly associated with chronic myelogeneous leukemia and in patients mismatched by more than two antigens.     

Actin polymerisation in neutrophils of rheumatoid arthritis patients in relation to treatment with non-steroidal anti-inflammatory drugs

The Azotobacter vinelandii nifBfdxNnifOQ operon is required for synthesis of the nitrogenase iron-molybdenum cofactor. To further characterize the roles of its gene products, specific antibodies against NifB and NifO were generated, and the NifB, NifO and NifQ gene products were visualized and identified in nitrogen-fixing A. vinelandii cell extracts by a combination of two-dimensional gel electrophoresis of radiolabelled extracts and immunological detection methods. The three proteins showed apparent pI and M(r) values similar to those expected from sequence data, except for NifO, which showed an apparent M(r) of ca. 23 kDa (vs. 16 kDa expected).     

Morbidity during the first year of life in small for gestational age infants

OBJECTIVE: To study the effect of early postnatal dexamethasone (days 1-3) on the incidence and severity of chronic lung disease in preterm infants with respiratory distress syndrome. METHODS: A multicentre, randomised, placebo controlled, blinded study was carried out in 18 neonatal intensive care units in Israel. The primary outcome measure was survival to discharge without requirement for supplemental oxygen therapy beyond 28 days of life. The secondary outcome measures were requirement for mechanical ventilation at 3 and 7 days, duration of ventilation or oxygen therapy, need for subsequent steroids for established chronic lung disease and incidence of major morbidities. RESULTS: The study consisted of 248 infants (dexamethasone n = 132; placebo n = 116). No differences were found in the outcome variables except for a reduction in requirement for mechanical ventilation at age 3 days in treated infants (dexamethasone 44%, placebo 67%; P = 0.001). Gastrointestinal haemorrhage, hypertension, and hyperglycaemia were more common in treated infants, but no life threatening complications, such as gastrointestinal perforation, were encountered. CONCLUSIONS: These data do no support the routine use of early postnatal steroids, but may justify further study in a selected, high risk group of infants.     

Extensive salivary contamination due to concurrent use of chewing tobacco during I-131 radioablative therapy

Although multiple authors have reported on various causes of external I-131 contamination after administration of radioiodine, to the authors' knowledge there have been no reported cases of external contamination from salivary secretions due to expectoration of chewing tobacco. A case of extensive I-131 contamination of a hospital room, furniture, and plumbing due to indiscriminate use of chewing tobacco during an inpatient I-131 radioablative therapy is presented.