Influence of urban pattern on inundation flow in floodplains of lowland rivers.

The objective of this paper is to investigate the respective influence of various urban pattern characteristics on inundation flow. A set of 2000 synthetic urban patterns were generated using an urban procedural model providing locations and shapes of streets and buildings over a square domain of 1×1km2. Steady two-dimensional hydraulic computations were performed over the 2000 urban patterns with identical hydraulic boundary conditions. To run such a large amount of simulations, the computational efficiency of the hydraulic model was improved by using an anisotropic porosity model. This model computes on relatively coarse computational cells, but preserves information from the detailed topographic data through porosity parameters. Relationships between urban characteristics and the computed inundation water depths have been based on multiple linear regressions. Finally, a simple mechanistic model based on two district-scale porosity parameters, combining several urban characteristics, is shown to capture satisfactorily the influence of urban characteristics on inundation water depths. The findings of this study give guidelines for more flood-resilient urban planning.

Calcitonin metabolism in senile (type II) osteoporosis.

The exact role of calcitonin (CT) in the pathogenesis of senile (Type II) osteoporosis remains unknown. Whole plasma calcitonin (iCT) and extracted monomeric calcitonin (eCT) basal levels, metabolic clearance rate (MCR) and production rate (PR) of iCT and eCT were measured in 41 postmenopausal women, including 14 hip fractures (OP II) and 27 healthy controls. No significant difference appeared for basal iCT levels between OP II (mean +/- SEM: 41.9 +/- 3.4 pg/ml) and controls (mean +/- SEM: 46.2 +/- 5 pg/ml). eCT basal levels were similar in OP II (mean +/- SEM: 5.42 +/- 0.5 pg/ml) and in controls (mean +/- SEM: 7.3 +/- 0.7 pg/ml). MCR were similar in the two groups. iCT PR were similar in OP II (mean +/- SEM: 17.2 +/- 1.5 micrograms/24 h) and controls (mean +/- SEM: 18.6 +/- 1.1 micrograms/24 h). No difference appeared between eCT PR in OP II (mean +/- SEM: 2.3 +/- 0.2 micrograms/24 h) and controls (mean +/- SEM: 3.2 +/- 0.3 pg/ml). From these data, no evidence appears that calcitonin might be one of the determinant factors in the pathogenesis of senile osteoporosis.

Antibodies to laminin in preeclampsia.

Laminin is a large basement membrane glycoprotein localized in the trophoblast, glomerular basement membrane and in the mesangial matrix of human glomeruli. It promotes the attachment of epithelial cells to basement membrane collagen. We have found that 14 sera from 52 patients with severe preeclampsia or eclampsia contain IgG and IgM antibodies which react with placental and kidney basement membranes. These antibodies were specific for laminin and did not react with other basement membrane proteins. They were able to fix complement. They have been demonstrated by radial immunodiffusion, radioimmunoassay and immunofluorescence blocking studies. In primary cultures they were shown to impair the attachment of trophoblast cells to basement membrane collagen. High levels of circulating immune complexes were detected only in sera from preeclamptic patients with circulating antibodies to laminin. The auto-antibodies to laminin could play a major role in the pathogenesis of severe preeclampsia by impairing the attachment of trophoblast cells to placental basement membranes and by fixation to the glomerular basement membranes and mesangial matrix.

[Neurophysins, vasopressin and cognitive function in aging]. / Neurophysines, vasopressine et fonctions cognitives au cours du vieillissement.

Neurophysins, vasopressin and oxytocin are not restricted to the hypothalamo-neuropituitary system but are also found in different brain area in relation with cognitive and emotional function and with cardiovascular regulation. During early aging it seems to exist a decrease of the hypothalamic and brain content of vasopressin. It appears that in some patients, presumably suffering from a deficit of central vasopressinergic function, exogenous vasopressin could improve arousal and/or memory. The exact place of this peptide in the treatment of the early aging cognitive deficit remains however to be defined.

P1 incompatibility in pigeon breeders.

Pigeon breeders of the P2 blood phenotype may develop anti-P1 haemagglutinins as a consequence of natural immunization to pigeon dust. The half-life of labelled P1 erythrocytes was determined in two P2 pigeon breeders otherwise compatible except for the presence of anti-P1 antibodies and in four compatible controls without anti-P1. The half-life of tagged cells was within the normal range in one breeder but significantly reduced in the other, indicating that P1 incompatibility may occur in vivo. Since anti-P1 antibodies are found in about 20% of P2 pigeon breeders, it is suggested that this group may be prone to developing an incompatibility to transfused P1 red cells.

Clofibrate and diabetes control in patients treated with oral hypoglycaemic agents.

1. Twenty-two maturity-onset type diabetics treated with oral hypoglycaemic agents entered a single-blind crossover study using placebo (periods A and C, 2 months each) and clofibrate (2 g/day; period B; 2 months). 2. In thirteen patients, under reasonably good control, clofibrate did not reduce fasting or post-prandial blood glucose, nor 24 h glycosuria; no improvement was noted in the M-value, an index of diabetes control. 3. In contrast, in nine patients, with poor diabetes control, clofibrate reduced 24 h glycosuria and significantly improved the M-value. 4. In all patients, clofibrate therapy was associated with a significant 19-23% reduction in plasma fibrinogen. 5. It is suggested that addition of clofibrate may be useful in maturity-onset diabetics not adequately controlled by diet combined with oral hypoglycaemic agents.

Anti-P1 activity in pigeon breeders' serum .

Antibodies against the P1 antigen of the P blood group system have been found in 34% of P2 pigeon breeders' sera and in only 6% of the control group. In pigeon breeders, this anti-P1 activity correlates with immunization to pigeon serum and can consistently be removed by absorption with pigeon erythrocytes, serum or droppings. It is concluded that P1 or a related antigen is present in the pigeon blood and drop-pings and that heavy exposure to pigeon dust, as may occur in pigeon breeders, is one of the factors capable of inducing IgM antibodies to P1 antigen. The clinical importance of this finding remains to be defined.

Immunization against avian proteins.

A study of sera of pigeon breeders showed a higher ratio of antibodies with an anti-P1 specificity in those who show clinical signs of allergic origin. By absorption of anti-P1 antibodies it was revealed that there exist in the cells, serum and excrement of pigeons, substances with antigenic properties similar to those of human P1 antigen. Pigeon breeders, and particularly those who show clinical signs of allergy, possess also other antibodies which precipitate specific antigens of pigeon serum.