Outer membrane protein A (OmpA) contributes to serum resistance and pathogenicity of Escherichia coli K-1.

We examined whether outer membrane protein A (OmpA) contributes to gram-negative pathogenesis by determining the effect of mutagenesis of ompA in a virulent Escherichia coli K-1 isolate. An OmpA mutant was generated by insertion of the transposon TnphoA, which was genetically modified to increase the efficiency of its delivery by conjugation. The mutant was less virulent than its parent strain in two models of E. coli K-1 infection. Equal inocula of the OmpA+ and OmpA- strains fed to neonatal rats resulted in a sevenfold-greater incidence of bacteremia at 72 h from the OmpA+ strain. The lethal effect of the OmpA- mutant was significantly less than that of the OmpA+ parent strain when inoculated onto the chorioallantoic membrane of 10-day embryonated chick eggs. There was, however, no difference between strains in growth characteristics under physiologic conditions, either in rat serum or in unembryonated chick eggs. In the presence of a 10-day chick embryo, there was a 10-fold increase in the survival and growth of the OmpA+ strain. Correction of the mutation in ompA with an E. coli K-12 ompA gene restored a level of virulence equivalent to that of the parent strain. The ompA mutant was more sensitive to the bactericidal effect of pooled human serum by the classical pathway of complement activation. These results suggest that OmpA contributes to E. coli K-1 pathogenesis by a mechanism which may involve increased serum resistance.     

Intestino-esophageal reflux following gastrectomy. Mechanism of action and effectiveness of esophago-jejunoplication

The influence of the type of reconstruction after gastrectomy upon the postoperative reflux was analyzed in 30 patients. The refluxed material could be directly gained by the long-term reflux aspiration test and, thus, the quality including bile acids could be evaluated. After esophago-jejunoplication and Roux en Y-derivation 5 out of 7 patients were asymptomatic; only one patient suffered from mild esophagitis. Total bile acid concentration was near to the test systems sensitivity. The result in 11 patients after esophago-jejunostomy without Y-en Roux, but with a preserved lower esophageal sphincter (LES) are similar to the former group, whereas in all cases of 12 patients in whom the LES was resected, severe reflux esophagitis and excessively elevated bile acid concentrations were present. These results confirm that a jejunoplication supports the antireflux effect of preserved parts of the LES. If--for oncologic reasons--the LES has to be resected, free intestinal-esophageal reflux is following. In these cases a Roux en Y-derivation is required.     

Versuche zur Bestimmung hypophysärer Gonadotropine im Urin mittels einer serologischen Methodik

Zusammenfassung Es wird über die Ergebnisse der Bestimmung hypophysärer Gonadotropine im Urin mittels einer eigenen serologischen Methodik berichtet. Im Nativ-Urin oder nach Fällung mit Aceton oder Alkohol wurden keine, im Vergleich zum Tierversuch verwertbaren, Ergebnisse erhalten. Dagegen zeigten Untersuchungen mit, nach dem Albertschen Verfahren gewonnenen, Extrakten erste ermutigende Resultate.     

Bovine Colostrum: Its Constituents and Uses

Colostrum is the milk produced during the first few days after birth and contains high levels of immunoglobulins, antimicrobial peptides, and growth factors. Colostrum is important for supporting the growth, development, and immunologic defence of neonates. Colostrum is naturally packaged in a combination that helps prevent its destruction and maintain bioactivity until it reaches more distal gut regions and enables synergistic responses between protective and reparative agents present within it. Bovine colostrum been used for hundreds of years as a traditional or complementary therapy for a wide variety of ailments and in veterinary practice. Partly due to concerns about the side effects of standard Western medicines, there is interest in the use of natural-based products of which colostrum is a prime example. Numerous preclinical and clinical studies have demonstrated therapeutic benefits of bovine colostrum for a wide range of indications, including maintenance of wellbeing, treatment of medical conditions and for animal husbandry. Articles within this Special Issue of Nutrients cover the effects and use bovine colostrum and in this introductory article, we describe the main constituents, quality control and an overview of the use of bovine colostrum in health and disease.     

A new concept in the surgical treatment of gastroesophageal reflux.

Surgical treatment of gastroesophageal reflux has been thought to depend on the construction of a valve mechanism at the gastroesophageal junction (GEJ). Recently, a silicone prosthesis that does not construct a valve has been introduced, and in preliminary studies in the human, shown to be effective in the treatment of reflux. A precise mode of action has not been demonstrated for the prosthesis. This study was undertaken to investigate the mechanics of the prosthesis and determine its effectiveness in an animal model. Six canine gastroesophageal specimens were excised and the lower esophageal sphincter (LES) simulated by a rubber band placed around the GEJ at a tension calibrated to give 25 mmHg "sphincter" pressure. Circumferential silk ligatures of varying length were then placed on the stomach 3.0 cm distal to the GEJ. With no ligature, the LES opening pressure (LESOP) was 8.0 mmHg, varying to 17.0 mmHg with an 8.0 cm ligature. Further, 24 adult mongrel dogs were randomly divided into four equal groups: controls, circular myomectomy of the LES alone, myomectomy combined with fundoplication, and myomectomy combined with implantation of the silicone antireflux prosthesis. Evaluation included manometry, endoscopy, and histology. Although only the normal sphincter and fundoplication responded physiologically, the prosthesis was just as effective in preventing reflux, as evidenced by reducing acid exposure time of myomectomized dogs from 35.4% to 1.8%, and by preventing endoscopic esophagitis. It was concluded that the silicone antireflux prosthesis acts in the same fashion as the ligature in the model, by interrupting distraction of the LES by gastric wall tension. This concept is an effective method for raising LESOP, treating experimental gastroesophageal reflux, and eliminating the sequelae of reflux. Long-term evaluations of the prosthesis are required.