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Biomedical subjects

R B Adams

Publications and source records attributed to R B Adams.

At least 37 records · Page 2Linked to original sources
PubMed1992

Aspergillus flavus wound infection following repair of a ruptured duodenum in a non-immunocompromised host.

Aspergillus flavus is generally considered to be an opportunistic organism, rarely causing clinical infections in the immunocompetent host. We present a case of a 79-year-old man without history of immunocompromise who developed a severe aspergillus wound infection in an open wound following repair of a traumatic duodenal perforation. Despite aggressive treatment, this invasive infection contributed significantly to his eventual demise.

Aged↗
PubMed1992

Peritonitis into the 1990s: changing pathogens and changing strategies in the critically ill.

To study the effect of severe illness on the nature of peritonitis and intra-abdominal abscesses, the microbiology and clinical course of patients operated on over a 1-year period with culture-proven intra-abdominal infections whose preoperative Acute Physiology and Chronic Health Evaluation (APACHE) II scores were greater than or equal to 15 (predicted mortality at least 50%) were examined. Twenty-nine patients were enrolled, and overall mortality was 52 per cent, with increasing mortality correlating with higher APACHE II scores. The organism most commonly isolated from the peritoneum was Candida albicans, followed by Enterococcus species, Enterobacter species, and Staphylococcus epidermidis. An increase in the mean of the APACHE II scores on Days 3 and 7 compared to the preoperative score was associated with a 91 per cent mortality, while a decrease was associated with only a 22 per cent mortality. The authors conclude that the microbiology of intra-abdominal infections is inherently different in severely ill patients and that longitudinal clinical scoring may be more useful than a single scoring in predicting outcome. These data suggest that trials to investigate the broadening of standard perioperative antimicrobial coverage in the ill and use of longitudinal clinical scoring to direct aggressive reintervention may be warranted.

Abdominal Pain↗
PubMed1991

Transient and distant infections alter later intraperitoneal abscess formation.

Transient nosocomial infections, such as line sepsis and pneumonia, are common in today's critical care patient population. Although generally well treated, the effect of these transient antigen exposures on the immune system is unclear. We have previously shown that prior intraperitoneal inoculation with live bacteria leads to increased numbers of intraperitoneal abscesses. Data presented here demonstrate in a murine model that two immunizations with live Escherichia coli, Bacteroides fragilis, or both, administered systemically via intracardiac injection or at a focal distant site in subcutaneous tissue, significantly increased the number of mixed E coli/B fragilis intraperitoneal abscesses when induced 1 week later. Further, immunization with E coli, either alone or in combination with B fragilis, increased the total number of anaerobes recovered per mouse. Transient or focal sublethal infections can significantly alter an animal's immune response to later infectious insults, particularly the formation of intraperitoneal abscesses.

Animals↗
PubMed1991

The peritoneal environment during infection. The effect of monomicrobial and polymicrobial bacteria on pO2 and pH.

Intraperitoneal (IP) abscesses frequently are composed of aerobes and anaerobes, and, in experimental models, a particulate adjuvant. The environmental changes effected by these components, either singularly or in combination, have not been well defined. The IP pO2, pH, and recoverable bacteria from the peritoneum of rats were quantified over 6 hours during simple aerobic and anaerobic infections and during mixed peritonitis with and without a sterile feces-barium sulfate adjuvant (SFA). Fourteen groups were studied, receiving intraperitoneally, at time of oxygen probe placement, 1 mL normal saline (control), Escherichia coli (EC), Bacteroides fragilis (BF), SFA alone, or a mixture of EC and BF, EC and SFA, BF and SFA, or EC, BF, and SFA. Control animals exhibited a stable IP pO2 and pH during 6 hours. In monomicrobial EC peritonitis, inocula well below the LD50 produced an increased IP pO2 and reduced arterial-peritoneal gradient (APG), with a stable IP pH. By 6 hours lethal doses of EC produced a dramatic decline in IP pO2, with no change in arterial pO2 as well as acidic IP and arterial pHs. Simple BF peritonitis caused no or minor elevations in IP and arterial pO2 with no change in pH. During mixed infections a significant decline in the IP pO2 and pH at 6 hours in those groups infected with both SFA and EC of a moderate, normally sublethal inoculation was observed, while arterial pO2 was unchanged and arterial pH was decreased only slightly. Concomitantly there was a significant increased number of aerobic bacteria in those groups with SFA as adjuvant compared to similar inocula without SFA. This study demonstrates the complex interactions of bacteria, sterile particulate adjuvant (SFA), and the host peritoneum. It suggests that the combination of SFA and aerobic bacteria alter the peritoneal environment to one permitting anaerobic growth and promoting abscess formation.

Animals↗
PubMed1991

Preexposure of the peritoneum to live bacteria increases later mixed intraabdominal abscess formation and delays mortality.

Intraabdominal infections are a major source of morbidity and mortality for the trauma and postoperative patient. Transient peritoneal contamination with bacteria after either intentional or unintentional violation of the gut are common. The effect of this intermittent antigen exposure upon later formation of intraabdominal abscesses is unclear. Previous experiments by others have demonstrated that repeated exposure to Bacteroides fragilis capsular polysaccharide can induce a T lymphocyte-mediated immunity to subsequent induction of pure B. fragilis abscess formation. In a murine mixed intraabdominal abscess model, preexposure to live Escherichia coli, B. fragilis, or both increased the number of later abscesses and in some cases their bacterial composition. Further, immunization with E. coli alone increased late mortality without altering overall mortality. These data suggest that the alterations of immune function produced by live, transient bacteria upon subsequent mixed intraabdominal abscess induction result in fundamentally different consequences from those observed after specific polysaccharide antigen exposure and subsequent monomicrobial abscess induction.

Abscess↗
PubMed1986

Complete tumor ablation with iodine 131-radiolabeled disialoganglioside GD2-specific monoclonal antibody against human neuroblastoma xenografted in nude mice.

The antibody 3F8, an IgG3 murine monoclonal antibody (MoAb) against disialoganglioside GD2, could target iodine-131 (131I) to established subcutaneous human neuroblastoma (NB) xenografts in BALB/c nude mice. 131I-radiolabeled MoAb (0.125-1 mCi) was injected iv. Tumor radioactivity over time was calculated from scintigraphy, and radiation dose to individual tumors was calculated. Tumor shrinkage occurred only with 131I-labeled 3F8, but not with nonradioactive 3F8 or radiolabeled irrelevant antibody. While the tumor of the control mice enlarged by tenfold, the treated tumor showed over 95% shrinkage by 12 days. Both the rate of shrinkage and duration of tumor response were dose dependent. Calculated doses of more than 10,000 rad could be achieved. Only those tumors that received more than 4,200 rad were completely ablated without recurrence. Recurrent tumors were not antigen negative or radioresistant. These results confirmed the prediction based on imaging studies that human NB xenografts could be effectively eradicated with the use of 131I-labeled MoAb 3F8 with tolerable toxicities.

Animals↗
PubMed1985

Assessment of an implantable ileostomy sphincter.

A totally implanted, intermittently inflatable, silicone rubber cuff, reservoir, and control mechanism were evaluated for use as an artificial sphincter in 18 female beagle dogs that had undergone ileostomy. The dogs were divided into daily 8-hour occlusion, test, and always open, control, groups. Animals were evaluated daily for continence and peristomal irritation. Quantitative aerobic and anaerobic cultures, measurements of ileal accommodation, net fluxes of H2O, Na, K, and taurocholate, fecal fat loss, and urinary excretion of oral 58Co X B12 plus mucosal suction biopsies were done at 4, 12, 24, and 36 weeks. Eight hours of daily occlusion caused dependable continence without causing damage to the underlying or upstream mucosa and significantly reduced the incidence of peristomal erosion (6.8 +/- 0.8 days/dog-days X 100 versus 50.7 +/- 7 days/dog-days X 100 [+/- SEM] [p less than 0.001]). Occlusion also promoted anaerobic bacterial growth (9.00 +/- 0.41 logs versus 6.70 +/- 0.58 logs [p less than 0.001]). Test animals showed significant capacitance accommodation of the terminal ileum without incurring defects in ileal absorptive or secretory function. Gangrenous herniation of small bowel through an aperture formed by an intestinal loop adhering to the capsule surrounding the cuff, device failure, and fibrotic obstruction occurred sporadically as late as 29 weeks after implantation. The artifical sphincter was effective and was physiologically well tolerated, but its specific liabilities require further address.

Animals↗
PubMed1983

Biopsy needle characteristics assessed in the laboratory.

Radiologists are frequently called upon to perform percutaneous biopsy. Selection of the proper needle is becoming more complex as the number of types increases and reports of better results with certain needles proliferate. The authors evaluated a wide variety of needles of different caliber, cutting tip, and bevel. Using a standard biopsy technique for in vitro specimens, the samples were analyzed quantitatively by precise weight measurement and qualitatively by cytopathological means. It was concluded that large-bore needles were superior to "skinny" needles, and small-bore needles having an acute bevel angle were superior to flat-bevel needles of similar gauge in terms of specimen size and preservation.

Biopsy, Needle↗