Evaluation of methoprene (Altosid XR) sustained-release briquets for control of culex mosquitoes in urban catch basins.

A sustained-release, briquet formulation of methoprene (Altosid XR), applied at a rate of one briquet per catch basin in Saginaw, Michigan, provided ca. 70% reduction in emergence of Culex pipiens and Cx. restuans adults, compared with nontreated catch basins, during a period of 15 wk in the summer of 1990. In a parallel study using one briquet per 10.5 liter bucket, there was 99% reduction in adult emergence of these species for a period of 12 weeks. The difference between catch basins and buckets may be attributable to water movement through the catch basins with each rainfall, causing a dilution of methoprene through time. However, both studies indicated that the briquets released methoprene for 12-15 wk, suggesting that this formulation may offer season-long control of Culex mosquitoes from urban catch basins in Michigan, with a single treatment of insecticide.     

Quality of life in surgically palliated complex congenital heart disease.

The outcome of surgical palliation was evaluated in 26 children with complex cyanotic congenital heart disease. Outcome was examined in terms of ongoing symptoms, exercise tolerance, and the ability to participate in normal childhood activities. An activity score was calculated and each child performed graded treadmill exercise testing. Breathlessness (24 (92%) children), respiratory infections (nine (35%) children), and leg cramps (eight 31%) children) were the most common physical disorders. Although formal exercise testing showed a clear reduction in exercise tolerance compared with age and sex matched controls, palliation had allowed 23 (89%) to function with moderate exercise limitation, three (11%) having severely limited activity. Parents underestimated the child's exercise tolerance in 80% of cases. Sixteen (62%) patients attended school full time, eight (31%) attended part time, and two (8%) received only home tuition. Palliative surgery can give children with a single functional ventricle a level of activity which allows them to take part in most childhood activities. Subjective estimates of exercise tolerance are inaccurate in this group of children, and formal exercise testing can contribute useful information to decision making about further surgical intervention.     

Only patients with dysplasia progress to adenocarcinoma in Barrett''s oesophagus.

Columnar lined oesophagus (Barrett's oesophagus) carries a risk for the development of adenocarcinoma. Epithelial dysplasia appears to be a precursor but the utility of this marker for predicting subsequent adenocarcinoma is unsettled. We therefore prospectively studied 81 patients with histologically proven columnar epithelium of at least the distal 3 cm of the tubular oesophagus with regular endoscopic biopsies for a total of 289.2 patient years (mean 3.6 years, range 0.5-8). Twenty three patients (28%) had epithelial dysplasia detected during follow up. Both patients with persistent high grade dysplasia present on initial biopsies developed adenocarcinoma after 2.6-4.5 years, despite the absence of gross macroscopic change. The initial single layer pleomorphic high grade dysplasia in one patient regressed to low grade dysplasia which has persisted for 1.5 years. Of 10 patients with initial low grade dysplasia, one progressed to adenocarcinoma in 4.3 years. The low grade dysplasia persisted unchanged in seven patients for 1.5-7 years and appears to have regressed in two patients after three to five years. Ten patients developed low grade dysplasia during the surveillance period. This has persisted unchanged in six patients from 0.5-5 years, regressed in three for 0.5-5 years and has appeared after the first yearly biopsy in one patient. No patient without dysplasia has developed adenocarcinoma. The incidence of adenocarcinoma in Barrett's oesophagus in this study is one case per 96 patient years. This is 61 times (95% confidence limits 12-176) the age adjusted incidence of oesophageal cancer in Australia. Persistent high grade dysplasia appears to be a sensitive indicator for the development of subsequent adenocarcinoma.     

An optimal viral peptide recognized by CD8+ T cells binds very tightly to the restricting class I major histocompatibility complex protein on intact cells but not to the purified class I protein.

CD8+ cytotoxic T lymphocytes recognize cell surface complexes formed by class I major histocompatibility complex (MHC-I) glycoproteins and antigenic peptides. We have identified a peptide nonamer (termed IV9) derived from the human immunodeficiency virus that is over a millionfold more active (at subpicomolar concentrations) than peptide analogues longer or shorter by one or two amino acid residues. Although IV9 does not detectably bind to isolated MHC-I molecules as measured by equilibrium dialysis, we quantitated its specific binding in unaltered form to MHC-I on intact cells. Less than 1% of cell surface MHC-I forms complexes with IV9, which suffices to trigger maximal cytotoxic T-lymphocyte activity. By contrast, a peptide dodecamer that includes the IV9 sequence and is active at micromolar concentrations does not bind to MHC-I on intact cells, raising the possibility that this longer peptide undergoes processing. Using stoichiometrically iodinated IV9 to obviate the ambiguities associated with trace labeling methods, we measured the dissociation kinetics of purified peptide/MHC-I complexes isolated by affinity chromatography and found these complexes to be exceedingly stable (t1/2 = 200-600 hr).     

Neurotransmitters and memory: role of cholinergic, serotonergic, and noradrenergic systems

In Alzheimer's disease (AD), pathological changes are found in the basal forebrain cholinergic system (BFCS), serotonergic raphe (RA), and noradrenergic locus coeruleus (LC) systems. The present study was designed to determine the extent to which selective damage in each of these systems individually could produce an impairment of memory, one of the clinical symptoms of AD. Rats were given selective lesions by injecting ibotenic acid into the nucleus basalis magnocellularis and medial septal area (i.e., BFCS); 5,7-dihydroxytryptamine into the medial and dorsal RA; and 6-hydroxydopamine (6-OHDA) into the LC or by ip injections of (2-chloroethyl)N-ethyl-2-bromobenzylamine HCl (DSP4). Levels of choline acetyltransferase (ChAT), norepinephrine, and serotonin verified lesion effectiveness and selectivity. Chronic changes in serotonergic-2 and beta-adrenergic receptors were also determined. Rats were tested in a delayed spatial alternation in a T-maze. BFCS lesions impaired choice accuracy with intertrial delays of 5, 30, and 60 s. RA lesions or DSP4 injections impaired choice accuracy only when the intertrial delay was 60 s. LC lesions (by 6-OHDA) did not impair choice accuracy at any delay. The results suggest that the pathological changes in the BFCS and RA are sufficient to produce the types of memory impairments associated with dementia, but the quantitative effects of pathology in these two systems are different.     

Melbourne trial of adjuvant immunotherapy in operable large bowel cancer

A controlled randomized clinical trial was undertaken to assess the ability of combined non-specific and specific immunotherapy to alter the disease-free interval and overall survival of patients with Stage B or C large bowel cancer. The immunotherapy consisted of a 2 year programme of vaccinations with BCG and neuraminidase-treated autologous tumour cells. Three hundred and one patients entered the trial. At 5 years of follow-up there is no evidence that this form of immunotherapy can alter either the disease-free interval or survival in this group of patients.     

Immunogenic and Antigenic Epitopes of Immunoglobulins Binding of Human Monoclonal Anti-D Antibodies to FcRI on the Monocyte-Like U937 Cell Line

Seventeen human monoclonal IgG1- or IgG3 anti-D-secreting clones have been examined for their ability to sensitise O+ red cells for Fc-receptor-mediated rosette formation with U937 cells. IgG3 but not IgG1 anti-D antibodies were able to mediate stable rosette formation with unstimulated U937 cells via interaction with the FcRI receptor. Decreasing FcRI density by incubating U937 cells with di-butyryl cAMP almost completely abolished rosette formation, whilst increasing FcRI density by incubating U937 cells with interferon-gamma increased the percentage of cells forming rosettes with IgG3- and IgG1-sensitised red cells. These data suggest that rosette formation between IgG anti-D-sensitised red cells and FcRI-expressing cells is dependent upon the density of IgG3 on the red cell surface, the density of FcRI on the effector cell, multiple FcRI/IgG interactions are required for stable rosette formation and that more FcRI/IgG1 than FcRI/IgG3 interactions are required.