Management of benign ureteral structures: open surgical repair or endoscopic dilation?

We reviewed 20 cases of ureteral strictures, 15 of which were secondary to ureteral trauma. Of the patients 6 were managed initially by open repair and 14 underwent endoscopic manipulation. All 6 open repairs were successful, compared to 9 of the 14 patients who underwent endoscopic dilation of the ureteral stricture. Of the 5 failures 3 were due to the inability to cannulate the strictured ureter with a guide wire and 2 failed to respond to balloon dilation. Of these 5 patients 4 were treated successfully by an open operation. There were no serious intraoperative or postoperative complications. The average hospitalization was less for the endoscopic group (2.1 days) compared to the open surgical group (8.3 days). Followup ranged from 6 to 48 months.

Pressure and Temperature Effects on Growth and Methane Production of the Extreme Thermophile Methanococcus jannaschii

The marine archaebacterium Methanococcus jannaschii was studied at high temperatures and hyperbaric pressures of helium to investigate the effect of pressure on the behavior of a deep-sea thermophile. Methanogenesis and growth (as measured by protein production) at both 86 and 90°C were accelerated by pressure up to 750 atm (1 atm = 101.29kPa), but growth was not observed above 90°C at either 7.8 or 250 atm. However, growth and methanogenesis were uncoupled above 90°C, and the high-temperature limit for methanogenesis was increased by pressure. Substantial methane formation was evident at 98°C and 250 atm, whereas no methane formation was observed at 94°C and 7.8 atm. In contrast, when argon was substituted for helium as the pressurizing gas at 250 atm, no methane was produced at 86°C. Methanogenesis was also suppressed at 86°C and 250 atm when the culture was pressurized with a 4:1 mix of H 2 and CO 2 , although limited methanogenesis did occur when the culture was pressurized with H 2 .

Antibody inhibition of HeLa cell invasion by Yersinia enterocolitica

Antisera were prepared in rabbits against formalized and heat-killed bacteria of Yersinia enterocolitica serotype O:5,27 and against formalized bacteria of serotype O:8. Both strains used for immunization demonstrated adhesion to and invasion of HeLa cells. Coating of the bacteria with antibody did not greatly alter adhesion (i.e., extracellular attachment) to HeLa cells; however, antibody against formalized bacteria of both serotypes inhibited HeLa cell invasion by the homologous and heterologous strains. The Fab fragments from purified immunoglobulins also demonstrated cross-reacting inhibition of HeLa cell invasion. Antibody against heat-killed bacteria of serotype O:5,27 had no inhibitory activity. Adsorption of the antiserum against formalized bacteria of serotype O:5,27 with lipopolysaccharide from the homologous strain removed anti-lipopolysaccharide antibody but did not remove the inhibitory activity. The antiserum against formalized bacteria of serotype O:8 showed no antibody against lipopolysaccharide from serotype O:5,27 and no agglutinins against heat-killed bacteria of this strain. From these results, it is tentatively suggested that protein structures are important in mediating epithelial cell invasion by Y. enterocolitica.

Obsidian Dating and East African Archeology

New experimental procedures have made it possible to establish specific hydration rates for the numerous compositional types of obsidian to be found at archeological sites in Kenya. Two rates are applied to artifacts from the Prospect Farm site, revealing a history of occupation extending back 120,000 years.