Xanthomonas maltophilia endophthalmitis after implantation of sustained-release ganciclovir.
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Biomedical subjects
Publications and source records attributed to E M Stroh.
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Orbital emphysema can be produced by trans-conjunctival migration of air from a high pressure airgun. In an industrial accident an 8 mm conjunctival laceration was produced in the superior fornix which acted as a portal of entry for air into the subconjunctival, subcutaneous, and retrobulbar spaces. Computed tomography revealed no evidence of orbital fracture and showed that traumatic orbital emphysema occurred without a broken orbital bone.
Iodine-based liquid radiographic contrast agents were placed in normal and tumor-bearing (Greene strain) rabbit eyes to evaluate their ability to block iodine-125 radiation. This experiment required the procedures of tumor implantation, vitrectomy, air-fluid exchange, and 125I plaque and thermoluminescent dosimetry (TLD) chip implantation. The authors quantified the amount of radiation attenuation provided by intraocularly placed contrast agents with in vivo dosimetry. After intraocular insertion of a blocking agent or sham blocker (saline) insertion, episcleral 125I plaques were placed across the eye from episcleral TLD dosimeters. This showed that radiation attenuation occurred after blocker insertion compared with the saline controls. Then computed tomographic imaging techniques were used to describe the relatively rapid transit time of the aqueous-based iohexol compared with the slow transit time of the oil-like iophendylate. Lastly, seven nontumor-bearing eyes were primarily examined for blocking agent-related ocular toxicity. Although it was noted that iophendylate induced intraocular inflammation and retinal degeneration, all iohexol-treated eyes were similar to the control eyes at 7 and 31 days of follow-up. Although our study suggests that intraocular radiopaque materials can be used to shield normal ocular structures during 125I plaque irradiation, a mechanism to keep these materials from exiting the eye must be devised before clinical application.
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We previously reported the occurrence of Vibrio parahaemolyticus in patients and the environment in the Pacific Northwest. The present studies compare the biochemical characteristics, Kanagawa hemolysin reactions, and plasmid profiles of 13 patient and 221 environmental isolates of the organism. Classical biochemical testing of the isolates revealed similar reactions for the clinical and environmental strains, and analysis in agarose gels revealed that 13 to 15% of the isolates had plasmids. The strains were tested for production of Kanagawa hemolysin on Wagatsuma agar, and 1.4% of environmental isolates and 23% of clinical isolates were positive. Clinical isolates from locally acquired extraintestinal infections were urease negative and Kanagawa hemolysin negative, isolates from locally acquired gastroenteritis cases were urease positive and Kanagawa negative, and isolates from traveler's diarrhea were urease negative and Kanagawa positive. Eight percent of the local environmental isolates were also urease positive and Kanagawa hemolysin negative. These findings suggest that expression of the Kanagawa hemolysin is not essential for the pathogenesis of V. parahaemolyticus infections. In addition, our findings suggest that V. parahaemolyticus gastroenteritis in the Pacific Northwest is associated with a urease-positive, Kanagawa-negative biotype of the organism.
Well defined heat doses (temperature X time) were applied to normal rabbit corneas in an effort to determine thermal tolerance, and to examine the effects of heat on this tissue. A purely conductive heater was chosen to minimize intraocular penetration, and avoid findings attributable to nonthermal effects of inductive sources. The etched element heater was sewn to 38 rabbit corneas. Thirty-six were treated to temperatures of 38, 45, 52 and/or 59 degrees centigrade for durations of 5, 15, or 45 min. Three eyes were treated at each time-temperature interval and sacrificed at either time 0, 1 day or 1 week follow-up. Histologic examinations were performed on all corneas. A corneal haze was first noted at 45 degrees C X 45 minutes X 1 day follow-up. This correlated with a mild stromal edema on light microscopy. Higher thermal doses produced a spectrum of damage, with complete destruction of all keratocytes and endothelial cells at 59 degrees C X 45 min. At levels greater than 45 degrees C x 45 min, heat damage was noted to be increased at 24 hr followup. Some recovery was noted by 1 week follow-up, with the exception of the 59 degrees C X 15 or 45 min groups. These two heat doses induced a drop-out of cellular elements with evidence of disintegration and fragmentation of collagen fibrils. Conductive heating of up to 45 degrees C X 15 min appeared well tolerated by normal rabbit corneas.
Studies were done to assess the role of oysters from the Pacific Northwest as a potential source of Vibrionaceae. Oysters collected from natural and cultivated populations on the British Columbia Coast were opened using sterile instruments. The gills and oyster meat were each removed, and the meat was cut in half. The gills and the cut surface of the oyster meat were each cultured by inoculating them directly to the surface of agar plating media for the isolation of Vibrionaceae. Overall, 120 oysters were cultured, and 60 yielded Vibrionaceae. Vibrio parahaemolyticus, Vibrio fluvialis, and Vibrio vulnificus were the most commonly isolated organisms. Vibrionaceae were most often recovered from oysters collected under warm-water conditions from natural stocks (83% positive), followed by oysters from the same sites collected under cold-water conditions (35% positive). Only 29% of oysters collected from cultivated commercial stocks under warm water conditions yielded Vibrionaceae, and no Vibrionaceae were isolated from oysters collected from these sites during periods when water temperatures were low. The results suggest that oysters are a significant source of potentially pathogenic Vibrionaceae in the Pacific Northwest. However, the risk of exposure to these bacteria can be reduced by consumption of cultivated oysters harvested under cold-water conditions.
The performance of four media for the isolation of Aeromonas strains from stool specimens, the importance of ampicillin-susceptible Aeromonas strains in the selection of culture media, and the usefulness of beta-hemolysis in screening blood-containing media for Aeromonas strains were evaluated in two phases. In the first phase, 36 of 1,672 stool specimens yielded Aeromonas isolates. Ninety-seven percent of the isolates were detected on blood agar containing 20 micrograms of ampicillin per ml (ABA), and 47% were detected on MacConkey agar containing 100 micrograms of ampicillin per ml and 1% Tween 80. In the second phase of the study, 43 of 1,924 stool specimens yielded Aeromonas isolates. Fifty-one percent of the isolates were detected on blood agar and on modified cefsulodin-Irgasan-novobiocin agar, and 84% were detected on ABA. The combination of ABA and modified cefsulodin-Irgasan-novobiocin agar provided 100% recovery of the Aeromonas isolates encountered. All of the Aeromonas isolates detected on blood agar were also detected on ABA, and 89% of the Aeromonas isolates detected on these media were beta-hemolytic. These results suggest that ABA is superior to the other media evaluated for the isolation of Aeromonas strains from stool specimens, but optimal recovery of the organism may require the use of more than one medium. The results also suggest that the occurrence of ampicillin-susceptible strains is not a limitation on the use of ABA, but at least 10% of Aeromonas isolates will be missed if beta-hemolysis is used to screen ABA plates for these organisms.
We prospectively compared the occurrence of Vibrio parahaemolyticus in patients and the environment in the Pacific Northwest. Inpatient and outpatient stool and wound specimens and water samples from 10 estuarine sites were cultured for V. parahaemolyticus over a period of 3 years. V. parahaemolyticus infections were detected in 13 patients (8 with gastroenteritis; 5 with wound infections), and all of the infections were found in outpatients in physicians' offices. Ten of the infections were locally acquired, and three occurred in patients returning from tropical travel. V. parahaemolyticus was isolated from 11 to 33% of the environmental samples, and each sampling site yielded the organism at some time during the study. V. parahaemolyticus was found in the environment only during the summer months, when water temperatures were greater than or equal to 17 degrees C and salinities were less than or equal to 13% (parts per thousand), and locally acquired infections were detected only when the organism was present in large numbers in the environment. We conclude that V. parahaemolyticus causes locally acquired gastroenteritis and wound infections, as well as traveler's diarrhea, in the Pacific Northwest, that patients with V. parahaemolyticus infections are likely to be seen in physicians' offices rather than hospitals, that locally acquired V. parahaemolyticus infections occur only when the organism is present in the environment, and that the organism is likely to be present during the summer months, when warm, low-salinity water conditions prevail in the coastal marine environment.