Identification and characterization of aquaporin-2 water channel mutations causing nephrogenic diabetes insipidus with partial vasopressin response

Congenital nephrogenic diabetes insipidus (NDI) is a rare disease caused most often by mutations in the vasopressin V2 receptor (AVPR2). We studied a family which included a female patient with NDI with symptoms dating from infancy. The patient responded to large doses of desmopressin (dDAVP) which decreased urine volume from 10 to 4 I/day. Neither the parents nor the three sisters were polyuric. The patient was found to be a compound heterozygote for two novel recessive point mutations in the aquaporin-2 (AQP2) gene: L22V in exon 1 and C181W in exon 3. Residue Cys181 in AQP2 is the site for inhibition of water permeation by mercurial compounds and is located near to the NPA motif conserved in all aquaporins. Osmotic water permeability (Pf) in Xenopus oocytes injected with cRNA encoding C181W-AQP2 was not increased over water control, while expression of L22V cRNA increased the Pf to approximately 60% of that for wild-type AQP2. Co-injection of the mutant cRNAs with the wild-type cRNA did not affect the function of the wild-type AQP2. Immunolocalization of AQP2-transfected CHO cells showed that the C181W mutant had an endoplasmic reticulum-like intracellular distribution, whereas L22V and wild-type AQP2 showed endosome and plasma membrane staining. Water permeability assays showed a high Pf in cells expressing wild-type and L22V AQP2. This study indicates that AQP2 mutations can confer partially responsive NDI.      

ICAM-3, the third LFA-1 counterreceptor,is a co-stimulatory molecule for both resting and activated T lymphocytes

Optimal activation of human T cells mediated by ligation of CD3/T cell receptor (TcR) complex requires co-stimulatory signals. These can be provided by the adhesive interaction between receptor molecules on T cells and their counter-receptors on antigen-presenting cells. Soluble ICAM-3, anti-ICAM-3 and anti-CD3 mAb were utilized to address the role of the ICAM-3/LFA-1 pathway in TcR/CD3-dependent or -independent T cell activation. Immunoaffinity-purified ICAM-3 co-immobilized with suboptimal concentrations of anti-CD3 monoclonal antibody (mAb) stimulated T lymphocytes as monitored by the expression of the lymphocyte activation antigens CD25 and CD69. The mechanism underlaying this activation appear to involve the interaction of ICAM-3 with a β2 integrin, likely to be LFA-1, since mAb to the CD18 chain completely inhibited T cell activation. Similar experiments demonstrated that anti-ICAM-3 mAb were able to co-stimulate both resting (cord blood) and activated (T cell clones) T lymphocytes. On the contrary, anti-ICAM-1 mAb were only co-stimulatory for CD25 expression on activated but not on resting T cells. In addition, we have found that some γδ T cell clones bearing the Vδ1 segment were activated by direct mAb engagement of ICAM-3 in the absence of TcR/CD3 occupancy. Furthermore, immobilized anti-ICAM-3 mAb also induced development of dentritic processes. In conclusion, our data suggest that ICAM-3 on the surface of both T cells and antigen-presenting cells plays an essential role in the initiation of the immune response.     

Differences in specificities of anti-centromere sera for the monomeric and dimeric C-terminal peptides of human centoromere protein C

Centromere protein-C (CENP-C), one of the centromere autoantigens and components of the inner plate of the kinetochore, is suggested to make a dimer at the C-terminus. In order to investigate the presence of conformation-specific anti-centromere antibodies (ACA) to the dimer form, the C-terminal 124 amino acids (CF-124) were expressed in Escherichia coli, affinity purified and chemically cross-linked. Immunoblotting was utilized to compare the reactivities between the dimers and the monomers against 58 ACA(+) sera. The reactivities of the dimers were obviously higher in both IgG and IgM responses. The dimer was still more reactive than the glutathione S-transferase-fused monomer in some sera. Two kinds of CF-124 mutant (each contained one amino acid change at the N-terminal region of CF-124) and two cut segments of CF-124 (67 N-terminal amino acids and 58 C-terminal amino acids) were also examined. The former two mutants decreased the dimerization activity. The latter two mutants lost both activities except for the faint dimerization activity of the N-terminal half. Affinity-purified antibodies with CF-124 in a liquid phase containing the co-purified GroE protein of E. coli, GroEL, reacted to the centromere in culture cells. In conclusion, there are heterogeneous autoepitopes including some conformational epitopes at the C-terminal CENP-C.     

Reevaluation of discograms not classified into usual classifications

Discograms of images that were eccentrically dyed because of insufficient infiltration of contrast medium are difficult to classify into the usual past discogram patterns. In this study, these types of images were detected in 40 discs of 36 patients with lumbar disc disease. We classified these images into the following three types, and analyzed the dye mechanisms in each case by computed tomography discographic findings: (1) type A (image of the annulus fibrosus only). Nine discs in nine cases. A part of the marginal annulus fibrosus was dyed. (2) type B (image of the right or left half of the nucleus pulposus). Eighteen discs in 15 cases. Unilateral dyeing was considered nucleus pulposus existing in the central region of the disc. (3) type C (partial image of the superior or inferior half of the nucleus pulposus). Thirteen discs in 12 cases. Only the superior or inferior half showing a cotton-ball pattern was dyed.     

Comparison of low attenuation areas on computed tomographic scans between inner and outer segments of the lung in patients with chronic obstructive pulmonary disease: incidence and contribution to lung function

BACKGROUND: The low attenuation areas on computed tomographic (CT) scans have been reported to represent emphysematous changes of the lung. However, the regional distribution of emphysema between the inner and outer segments of the lung has not been adequately studied. In this study the regional distribution of low attenuation areas has been compared by quantitative CT analysis and the contribution of the regional distribution to pulmonary function tests evaluated in patients with chronic obstructive pulmonary disease (COPD). METHODS: Chest CT images and the results of pulmonary function tests were obtained from 73 patients with COPD. The lung images were divided into inner and outer segments in the upper (cranial), middle, and lower (caudal) sections. The percentage ratio of low attenuation area to corresponding lung area (LAA%) was then calculated. The LAA% of each segment was also compared with the results of pulmonary function tests. RESULTS: The mean (SD) LAA% of the inner segment was 39.1 (18.5) compared with 28.1 (13.2) for the outer segment (p<0.0001). Linear and multiple regression analyses revealed that airflow limitation is closely correlated with the inner segment LAA% of the lower lung. In contrast, the carbon monoxide transfer factor is closely correlated with the inner segment LAA% of the upper lung. CONCLUSION: Low attenuation areas on CT scans are more often found in the inner segment of the lung than in the outer segment, and the contribution of the inner segment to pulmonary function tests may be greater than the outer segment.     

Magnolol inhibits leukotriene synthesis in rat basophilic leukemia-2H3 cells

We have observed an inhibitory action of magnolol on the production of leukotriene (LT) C4 and LTB4, important lipid mediators in allergy and inflammation. IgE- and A23187-stimulated production of LTC4 and LTB4 was measured by radio-immunoassay (RIA) in the absence or presence of various concentrations of magnolol in intact rat basophilic leukemia (RBL)-2H3 cells. Magnolol dose-dependently inhibited synthesis of LTC4 and LTB4. Magnolol inhibited the IgE-mediated increase of intracellular calcium ion concentration, resulting in the inhibition of cytosolic phospholipase A2 (cPLA2) and possibly 5-lipoxygenase (5-LO), both calcium ion-dependent enzymes. In cell-free studies magnolol inhibited LTC4 synthase activity. LTA4 hydrolase activity was only inhibited at the higher concentration (2.5 x 10(-5)M). These results indicate that magnolol inhibits production of LTs by inhibiting PLA2, 5-LO, LTC4 synthase and LTA4 hydrolase which are essential for LT-synthesis. Magnolol may have anti-allergic effect by blocking LT-synthesis.     

PREVALENCE OF MICROALBUMINURIA IN NON-INSULIN-DEPENDENT DIABETES MELLITUS

The prevalence of microalbuminuria was assessed in 50 patients of non-insulin dependent diabetes mellitus. The mean age of patients was 52.1 ± 11.6 years and the duration of diabetes was 8.3 ± 6.8 years. Twenty (40%) patients had microalbuminuria. Microalbuminuria was more common in patients with a longer duration of diabetes (more than 5 years), a poor glycaemic control, and higher systolic blood pressure.KEY WORDS: Microalbuminuria, Diabetes mellitus, Diabetic nephropathy, Chronic renal failure     

Occlusion of the cerebral arteries in Recklinghausen's disease

Summary Two children, aged 18 months and 6 years, who had Recklinghausen's disease, had occlusion of cerebral arteries. One child had no motor deficit but the other had right hemiparesis and partial occlusion of the left posterior cerebral artery, a fact not found in the literature.     

A new periodogram using one-way analysis of variance for circadian rhythms

A new periodogram was proposed using one-way analysis of variance (ANOVA), termed ANOVA periodogram, in order to reveal a precise significant periodicity. Thirty 3-day complex computer-simulated time series with known periodicity (24 h) and three 2-h data-missing occurring periodically (23 h, 20 min) were used to compare the ANOVA periodogram with Enright's one. In results, the ANOVA periodogram was superior to Enright's periodogram in the accuracy of assessing the major periodicity.