A family study of hydrocephalus resulting from aqueduct stenosis.

Stenosis of the aqueduct of Sylvius accounts for about one third of cases of congenital hydrocephalus. At least 32 families have been reported in which the aqueduct stenosis is inherited in an X linked fashion. In half of these families, flexed adducted thumbs were noted in some affected family members. Occasionally other male members were mentally retarded, suggesting limited expression of the gene. The problem of giving genetic advice to an isolated, clinically unremarkable, case of aqueduct stenosis remains, so a family study was undertaken based on 24 such cases seen at The Hospital for Sick Children over a 19-year period. There were 15 male and nine female index patients. The diagnosis was confirmed in all cases by air encephalogram. One boy had a radial club hand and another developed clasped thumbs secondary to spasticity. No cases had hyaloidoretinal dysplasia. The 15 boys had 18 brothers and 19 sisters, of whom one sister was similarly affected. The nine girls had 12 sibs, none of whom was affected. This study, combined with a similar study in the USA, suggests that the empirical risk of recurrence of a sporadic case of aqueduct stenosis is about 4.5%.     

Role of selectins in local and remote tissue injury following ischemia and reperfusion.

Ischemia (4-hour) followed by reperfusion (4-hour) of rat hind limbs results in local injury as well as remote (lung) injury. It has recently been shown that injury in this model is neutrophil- and cytokine-dependent and requires the beta 2 integrin adhesion molecules CD11a/CD18 and CD11b/CD18. The role of selectins in events leading to injury (as determined by leakage of albumin and by hemorrhage) was assessed either through the use of blocking antibodies to L-, E- or P-selectins or by the use of oligosaccharides that are reactive with selectins. Lung injury was found to be L- and E-selectin-dependent. When the ischemia and reperfusion times were reduced, lung injury was also found to be P-selectin dependent. In the case of hind limb injury involving the crural muscle mass, injury was L-selectin-dependent but independent of requirements for P- and E-selectin. Injury in both organs was blocked by the infusion of sialylated Lewis pentasaccharide, whereas sialyl-N-acetyllactosamine pentasaccharide failed to protect against injury. In general, when selectin-blocking approaches were protective, there were parallel reductions in tissue content of myeloperoxidase. These data underscore the role of selectins in ischemia-reperfusion injury and suggest that selectin requirements may vary with the vascular bed under study.     

Accumulation of very long-chain fatty acids does not affect mitochondrial function in adrenoleukodystrophy protein deficiency

X-linked adrenoleukodystrophy (X-ALD, OMIM 300100) is a severe inherited neurodegenerative disease, associated with the accumulation of very long-chain fatty acids (VLCFA). The recent unexpected observation that the accumulation of VLCFA in tissues of the Abcd1-deficient mouse model for X-ALD is not due to a deficiency in VLCFA degradation, led to the hypothesis that mitochondrial abnormalities might contribute to X-ALD pathology. Here, we report that in spite of substantial accumulation of VLCFA in whole muscle homogenates, normal VLCFA levels were detected in mitochondria obtained by organellar fractionation. Polarographic analyses of the respiratory chain as well as enzymatic assays of isolated muscle mitochondria revealed no differences between X-ALD and control mice. Moreover, analysis by electron microscopy, revealed normal size, structure and localization of mitochondria in muscle of both groups. Similar to the results obtained in skeletal muscle, the mitochondrial enzyme activities in brain homogenates of Abcd1-deficient and wild-type animals also did not differ. Finally, studies on mitochondrial oxidative phosphorylation in permeabilized human skin fibroblasts of X-ALD patients and controls revealed no abnormalities. Thus, we conclude that the accumulation of VLCFA per se does not cause mitochondrial abnormalities and vice versa-mitochondrial abnormalities are not responsible for the accumulation of VLCFA in X-ALD mice.     

Validation of an equation for predicting energy cost of arm ergometry in women

Few studies have examined the validity of metabolic equations for the prediction of energy cost (VO(2)) of arm ergometry in women. Therefore, the purpose of this study was (a) to compare directly measured and predicted VO(2) values using the American College of Sports Medicine (ACSM) equation and (b) to develop and validate a prediction equation for women. A sample of 60 female subjects with mean (+/-SD) age, weight and height 26.5 +/- 14.4 years, 61.5 +/- 7.6 kg, 163.3 +/- 6.0 cm, respectively, was randomly assigned to an equation group (N = 40) and a cross validation group (N = 20). All subjects performed an incremental arm ergometry test (10 W increases every 2 min), until termination criteria were met. Repeated measures ANOVA indicated significant differences between the measured VO(2) and ACSM predicted VO(2) during all the incremental test work rate. Multiple linear regression analysis was used to develop the following upper body exercise VO(2) prediction equation: VO(2)(ml . kg(-1) . min(-1) = 23.461 - (0.272 x Body Weight) + (0.403 x watts) [R(2) = 0.82, SEE = 2.79] Cross validation indicated lower variability using the current prediction equation. An additional independent sample of 13 subjects performed a 30-min steady-state test at 40% of their pre-determined maximal work rate. VO(2) measured during the 30 min steady-state test (was significantly different P < 0.05) from the ACSM prediction at all time intervals. There were no significant differences using the above equation following the 5 min time interval. Therefore, a new equation is proposed as a means of providing a gender-specific energy cost prediction equation.     

Pulmonary endothelial cell killing by human neutrophils. Possible involvement of hydroxyl radical

Human blood neutrophils stimulated by a variety of agents were shown to have cytotoxic effects on bovine pulmonary artery endothelial cells. Effective agonists included immune complexes, opsonized zymosan and 12-O-tetradecanoyl phorbol acetate. Unstimulated human neutrophils and neutrophils stimulated with N-formyl-methionyl-leucyl-phenylalanine or with platelet-activating factor failed to induce significant killing even though secretory release of lysosomal enzymes occurred. In comparing the effects of the different agonists, endothelial cell killing showed a better correlation with the production of H2O2 than with the generation of O2-. Endothelial cell killing by stimulated human neutrophils was inhibited by catalase but not by soybean trypsin inhibitor or superoxide dismutase. Killing was also inhibited by two scavengers (N, N-dimethylthiourea and D-mannitol) of hydroxyl radical and by deferoxamine mesylate, an iron-chelator. Iron-saturated deferoxamine mesylate was significantly less effective in protecting the endothelial cells against killing. Agents that were protective against endothelial cell killing did not interfere with the generation of O2- in stimulated neutrophils. These results suggest that leukocyte-induced endothelial cell killing in vitro can be induced by some but not all agonists for neutrophils and that the killing is oxygen-dependent and may be directly due to hydroxyl radical production.     

Antibodies to Epstein-Barr virus-induced early antigens in blood donors

IgG class antibodies to the early antigen complex (EA; D + R components) of the Epstein-Barr virus (EBV) were found by indirect immunofluorescence in titres greater than or equal to 1:10 in 196 (49.4%) out of 397 blood donors and titres greater than or equal to 1:20 in 84 (21.2%) of these subjects. Anti-EA titres of greater than or equal to 1:2560 were detected in 6 sera, anti-EA(D) only in 17 donors (4.3%). Additional EBV-specific antibody tests were performed in sera with anti-EA-IgG titres of greater than or equal to 1:20 (n = 84), including IgM class antibodies to virus capsid antigen (anti-VCA-IgM). Specific IgM revealed active EBV infection in 12 blood donors. There was no correlation between the presence of anti-VCA-IgM and the magnitude of anti-EA-IgG titres. Therefore, it seems to be impossible to define the threshold titre for EA antibodies indicating active EBV infection. For this purpose probably a titre increase should be demonstrated in paired sera.     

Cystatin C predicts renal function impairment after partial or radical tumor nephrectomy

International Urology and Nephrology - To test the value of preoperative and postoperative cystatin C (CysC) as a predictor on kidney function after partial (PN) or radical nephrectomy (RN) in...     

Growing fractures of the skull

Tne cases of growing fractures seen in the last 10 years are presented. Six of the patients sustained their injury within the first six months of life. The defects formed rapidly, several within two or three months after injury. There was enlargement of the defect in only one case after the date of discovery. Although the defects involved the parietal bone most commonly, in four out of 10 the lesion crossed either the coronal or the lambdoid suture. The edges of the defects were usually thickened; in some areas they were saucer-shaped but in two cases there was erosion of the outer table of the skull at a distance from the margin of the defect, the erosion being related to an extracranial fluid-filled cavity in continuity with a porencephalic cyst. The ipsilateral ventricle was usually dilated and in a number of cases was associated with a porencephalic cyst. In no case was a "leptomeningeal cyst" found beneath the defect at operation. A detailed review confirms many of the findings previously described but suggests that the pathology of the condition is still not fully understood. Computed tomography, undertaken in one case, appears to be the examination of choice. Further light may be thrown on the pathogenesis of this condition by the use of intracystic, intrathecal, and intraventricular water-soluble contrast media.     

Cytodifferentiation in the acute myeloblastic leukemias of man.

Correlation analysis of numbers of colony-forming progenitor cells was used as an approach to the quantitation of human pluripotent stem cells. Marrow specimens were obtained from 24 patients with untreated acute myeloblastic leukemia, 22 patients under treatment, and 29 patients with no hematologic malignant disease. Three classes of progenitor cells were assayed: burst-forming units dependent on erythropoietin (BFU-E), colony-forming units dependent on erythropoietin (CFU-E), and granulopoietic progenitors (CFU-C). Significant positive correlations between numbers of BFU-E, CFU-E, and CFU-C were found in all 3 groups of patients. In contrast, no such positive correlations were seen between marrow blasts and any of the classes of colony-forming progenitors. These results were compatible with a shared relationship of the colony-forming progenitors to a pluripotent cell of origin and raised the possibility that the immediate progenitors of the blasts may not be any of the myelopoietic progenitor cells monitored in these studies.