Closed rupture of the anterior tibial tendon. A case report

Closed subcutaneous rupture of the anterior tibial tendon is a relatively uncommon injury that requires a thorough clinical examination to diagnose correctly. The authors report a case of this disorder and provide a review of the relevant literature. A method of surgical repair not previously described in the literature is also presented.     

Involvement of calcium in interactions between gingival epithelial cells and Porphyromonas gingivalis

Porphyromonas gingivalis, a periodontal pathogen can invade primary cultures of gingival epithelial cells. This invasion was significantly inhibited (74-81%) by thapsigargin and 1,2-bis(2-aminophenoxy)ethane-N,N,N1,N1-tetraacetic acid, acetoxymethyl ester (BAPTA/AM), but not by EDTA or amiloride. Release of Ca2+ from an intracellular store and the subsequent increase in cytosolic [Ca2+] may, therefore, be involved in the invasion process, while Ca2+ influx is not. Moreover, cytosolic [Ca2+] was found to increase transiently in about 30% of gingival epithelial cells acutely exposed to P. gingivalis, but not in unexposed cells, or in cells exposed to noninvasive Escherichia coli. These findings indicate that P. gingivalis invasion of epithelial cells is correlated with activation of [Ca2+]-dependent host cell signaling systems.     

Numerical quadrature used for radiative heat-transfer computations

Physical reasoning makes it possible to use artificial parameters with numerical quadrature in order to obtain approximate solutions for the Fredholm integral equations associated with radiative heat transfer calculations. With the aid of such parameters, decisions can be made concerning the applicability and usefulness of the numerical quadrature technique.     

The post-mortem pH of cod and haddock muscle and its seasonal variation.

The post-mortem pH of cod muscle, which strongly influences its attributes as a food, is subject to seasonal variation. For most of the year the average of a batch lies above about 6.7, but for a short time in the summer it suddenly drops to low values, rising again just as suddenly. It is now thought that heavy feeding immediately after starvation causes this sharp fall. Fillets from fish frozen at such a time gape and have a tough texture after cooking. The low-pH period is fairly short, so cod are in fact suitable for freezing for all of the year outside certain summer months. The phenomenon has been observed in cod from a wide range of fishing grounds. Haddock show no such seasonal variation, but their post-mortem pH is lower on average than that of cod.     

Genetic algorithm compared to nonlinear optimization for labour and equipment assignment

The genetic algorithm is a technique based on evolutionary optimization. A methodology for optimizing labour and equipment assignment using the genetic algorithm is presented. A number of modifications are introduced to the three operators of the genetic algorithm, namely, reproduction, crossover and mutation. Results from the genetic algorithm are compared to the nonlinear optimization technique in solving the labour and equipment assignment problem. A comparison of the two techniques indicates that the genetic algorithm has the capacity to ensure a global optimal solution. However, its computational operations take longer than the nonlinear optimization technique in obtaining near-optimal or optimal solutions.

L'algorithme genetique est une technique qui repose sur l'optimisation evolutive. Le present article propose une methodologie qui utilise cet algorithme pour optimiser les affectations de main d'u uvre et d'equipements. Un certain nombre de modifications est apporte aux trois operateurs de l'algorithme, a savoir, la reproduction, la permutation et la mutation. On compare ensuite les resultats de l'algorithme genetique a la technique d'optimisation non-lineaire utilisee pour resoudre les problemes d'affectation de main d'u uvre et d'equipement. La comparaison des deux techniques fait apparaitre que l'algorithme genetique peut deboucher sur une solution optimale globale. Il convient cependant de noter que pour parvenir a des solutions quasi optimales ou optimales, les calculs sont plus longs qu'avec la technique d'optimisation non lineaire.     

Cytotoxicity-associated effects of reactive oxygen species on endothelin-1 secretion by pulmonary endothelial cells

In this study bovine pulmonary artery endothelial cells (BPAEC) were used as a model system to investigate the effects of the hypoxanthine-xanthine oxidase (HXXO) oxygen radical donor system on ET-1 secretion into pulmonary vasculature. Incubation of BPAEC with HXXO for 4 h caused a significant reduction in ET-1 secretion, which was significantly offset by allopurinol or catalase, but not by Cu/Zn superoxide dismutase (SOD). ET-1 secretion was also reduced by H2O2, and this effect was again significantly offset by catalase. XO alone also reduced ET-1 secretion, but to a significantly lesser degree than did HXXO, and this effect was not offset by allopurinol, catalase, or SOD. None of the oxidant treatments were associated with a loss of immunoreactive ET-1 from endothelial cell medium containing synthetic peptide. The HXXO- and H2O2-mediated reductions in ET-1 secretion were accompanied by evidence of reduced cell viability. This loss of viability was absent when cells were treated with HXXO + catalase, allopurinol, or mercaptopropionyl glycine, but not when SOD was present. We conclude that under conditions of oxidative stress, the pulmonary vascular endothelium responds by secreting less ET-1. This may be relevant to its vasodilator functions in the pulmonary vasculature, which would therefore be compromised when the endothelium is exposed to oxidant stress.