Vesicular targeting and the control of ion secretion in epithelial cells: implications for cystic fibrosis.

Non-polarized HT-29 colonic epithelial cells fail to respond to cyclic AMP-generating agonists with increases in plasma membrane anion conduction. Radio-isotopic efflux and patch-clamp experiments revealed that both undifferentiated and differentiated HT-29 colonocytes possess volume- and Ca(2+)-activated Cl- channels. However, only within the apical plasma membranes of the latter were cystic fibrosis transmembrane conductance regulator (CFTR) Cl- channels found. CFTR was expressed equally well in both non-polarized and polarized colonocytes. Lack of CFTR-dependent anion conduction was shown to be the result of CFTR retention within a peripheral intracellular compartment. We demonstrate that upon polarization, CFTR moves to the apical plasma membrane via a Brefeldin A (BFA)-sensitive intracellular trafficking pathway.     

The potentiating effect of rheumatoid arthritis serum in the immediate phase of nephrotoxic nephritis

Nephrotoxic nephritis induced in rats was employed as an experimental model to investigate the possible effects of rheumatoid factor on in vivo antigen–antibody reactions. Rats injected simultaneously with rheumatoid arthritis serum and rabbit nephrotoxic globulin showed a three-fold increase in immediate proteinuria compared with rats injected with nephrotoxic globulin alone. This potentiating effect of rheumatoid arthritis serum was evident even when the serum was injected 48 hr after the nephrotoxic globulin and was also apparent to a lesser extent in rats decomplemented by a prior injection of aggregated human IgG. Normal human serum had no effect on the proteinuria produced by a standard dose of nephrotoxic globulin while rheumatoid arthritis serum injected with normal rabbit globulin did not increase urinary protein excretion above baseline levels. In rats injected with rheumatoid arthritis serum and nephrotoxic globulin, human IgM (presumably rheumatoid factor) was detected by immunofluorescence on the glomerular basement membrane along with the nephrotoxic globulin and rat complement and persisted at this site for as long as 42 days after the initial injections. Rheumatoid factor activity was also recovered by elution from glomeruli isolated from rat kidneys 24 hr after the injection of rheumatoid arthritis serum and nephrotoxic globulin.     

Attentional characteristics of infants and toddlers with Williams syndrome during triadic interactions

Two studies were conducted to consider the looking behavior of infants and toddlers with Williams syndrome (WS).In Study 1,the looking behavior of a 10-month-old girl with WS during play sessions with her mother and with a stranger was compared to that of 2 groups of infants who were developing normally (ND),1 matched for chronological age and the other for developmental age. The infant with WS spent more than twice as much time looking at her mother as the infants in either contrast group did. She also spent twice as much time looking at the stranger.In addition, during 78%of this time, her gaze at the stranger was coded as extremely intense. Looks of this intensity were virtually never made by the ND infants. In Study 2,the looking behavior of 31 individuals with WS ages 8 to 43 months during a genetics evaluation was compared to that of 319 control children in the same age range (242 with developmental delay due to causes other than WS).Twenty-three of the 25 participants with WS aged 33 months or younger demonstrated extended and intense looking at the geneticist. In contrast, none of the control participants looked extensively or intently at the geneticist. Findings are discussed in the context of previous research on arousal and focused attention during normal development and on temperament and personality of older children and adults with WS. It is argued that the unusual looking patterns evidenced by infants and toddlers with WS presage the unusual temperament and personality of older individuals with WS, and the possibility of a genetic basis for these behaviors is addressed.     

Delineation of the male phenotype in carniofrontonasal syndrome

We are reporting on a 4-generation family in which 6 individuals had frontonasal dysplasia with variable extracranial abnormalities. All affected persons had hypertelorism, bifid or broad nose, and highly arched palate. Associated abnormalities included cleft lip and palate (1/6), webbed neck (2/6), Sprengel anomaly (2/6), pseudoarthrosis of the clavicle (2/6), pectus excavatum (3/6), narrow, sloping shoulders (3/6), diaphragmatic hernia (2/6), broad first toe (4/6), brachydactyly (3/6), fifth finger clinodactyly (5/6), longitudinal grooves of nails (5/6), shawl scrotum (2/3 males), first degree hypospadias (1/3), and mild mental retardation (1/6). Only one affected female had brachycephaly and right coronal synostosis. Four other affected relatives had varying degrees of facial asymmetry, but normal skull contour. No male to male transmission is observed, and both daughters of an affected male were affected. Based on the phenotype of the 3 affected females, craniofrontonasal syndrome (CFNS) is the likely diagnosis. However, there are 3 affected males in this kindred, and 2 of the 3 had significant anomalies. Affected males also had genital abnormalities and pectus deformity of the chest, not previously reported in this condition. Two of the 3 males have posterolateral diaphragmatic hernia. This family expands the phenotype of affected males.     

Differential effects of interleukin-4 in peptide induced autoimmunity

BALB/c mice immunized with multimeric DWEYSVWLSN develop IgG1 anti-DNA antibodies and glomerular immunoglobulin deposits, leading us to investigate the role of IL-4 in this model of antigen induced lupus. Splenocytes from DWEYSVWLSN immunized mice secreted IL-4 but not gamma-interferon. Following peptide immunization, IgG1 anti-peptide and anti-DNA antibodies were significantly higher in IL-4 wild type mice, while IgM and IgG3 anti-DNA levels were significantly higher in IL-4 knockout mice. Titers of IgG anti-laminin and anti-histone, but not anti-Sm/RNP and anti-cardiolipin antibodies, were significantly higher in the IL-4 wild type group. Glomerular immunoglobulin deposition was substantially decreased in IL-4 knockout mice. We conclude that while IL-4 does not materially affect the generation of some autoantibody responses associated with peptide induced autoimmunity, IL-4 deficiency inhibits kidney immunoglobulin deposition. The effect of IL-4 on humoral autoimmunity in lupus is complex, and is dependent on genetic background, the antigenic trigger and stage of disease.     

Immunoradiometric assay for cytomegalovirus-specific IgG antibodies: assay development and evaluation in blood transfusion practice

An immunoradiometric assay (radio-immunosorbent test; RIST) for the detection of IgG antibodies to human herpesvirus 4 [human cytomegalovirus (CMV)] has been developed. The technique utilizes CMV antigen passively adsorbed to a polyvinyl microtitration plate and a radiolabelled murine monoclonal anti-human IgG antibody to detect binding of human antibody to the 'solid phase' reagent. The assay was optimized, and its specificity confirmed by testing paired acute and convalescent sera from patients with acute CMV or other human herpesvirus infections. To determine the assay's sensitivity 1433 blood donor sera were examined. The RIST was more sensitive than a standard complement fixation (CFT), in that 53% of these sera were positive by RIST and 48% positive by CFT. There were 1303 concordant results, 88 sera positive only by RIST and 19 sera were only positive by CFT. These discrepant results remained after an attempt to exclude false positive reactivity; their significance is discussed. Use of a monoclonal anti-human IgG antibody in the RIST reduced non-specific binding to the control uninfected cell antigen such that blood donor sera could be tested in the assay using only a CMV antigen without generating an unacceptable false positive rate.     

A novel dystrophin isoform is required for normal retinal electrophysiology

Dystrophin is present in the outer plexiform layer of the retinaand is required for normal retinal function as measured by electroretinography.We describe the identification of a novel isoform of dystrophln(Dp260) present in the mouse retina. The unIque 5' terminusof the mRNA originates from a newly identified exon and is splicedin frame to exon 30 of the Duchenne muscular dystrophy (DMD)gene. The retinal isoform of dystrophln has 13 novel amino acidsas its N-terminus followed by most of the dystrophin rod domainand the cysteine-rich C-terminal domains. Analysis of mousetissues indicated this isoform of dystrophin Is expressed inretina, brain and cardiac tissue. Comparison of retinal electrophysiologyin mdx and mdx^cv3 mouse suggests that Dp260 is required fornormal retinal function.     

Investigation and comparison of some models for removing ocular artefacts from EEG signals

An investigation of ocular artefacts (OAs) in the human electroencephalogram (EEG) to quantify the effectiveness of OA removal, and to find the most effective model for removing OAs online is described. It was found unnecessary to use the vertical and horizontal EOGs of both eyes, although more than one EOG signal is required for adequate OA removal. The model using the vertical right EOG and the two horizontal EOGs was the best overall, but in most cases the use of only the vertical and horizontal right EOGs was sufficient. OAs were not completely removed by any of the models investigated, suggesting that more complex models are necessary.