PubMed Health⌕ Search

Biomedical subjects

B McCurdy

Publications and source records attributed to B McCurdy.

7 recordsLinked to original sources
PubMed1999

Helicobacter pylori products upregulate neutrophil superoxide anion production.

Helicobacter pylori-neutrophil interactions may play a pathogenic role in H. pylori-induced gastritis and peptic ulcer disease. To understand these interactions, we explored the effects of H. pylori-derived products on neutrophil chemotaxis and superoxide anion production. H. pylori bacteria were cultured and supernatants fractionated. Neutrophil chemotactic activity was confirmed in the crude supernatants and in one fractionated peak corresponding to a previously described neutrophil chemotactic factor. H. pylori-derived crude supernatant, sonicate and all chromatography-derived peaks failed to directly stimulate neutrophil superoxide anion production. However, after pretreatment with sonicate, neutrophils demonstrated increased superoxide anion production (priming) following subsequent exposure to the secretagogue fmet-leu-phe. These results suggest that H. pylori products may attract neutrophils to the gastric mucosa without initially stimulating superoxide anion production or tissue injury. Oxygen radical-mediated gastric mucosal injury may subsequently result when these primed neutrophils undergo additional stimulation by as yet unidentified factors.

Chemotaxis, Leukocyte↗
PubMed1997

A prospective randomized trial of an antibiotic- and antiseptic-coated central venous catheter in the prevention of catheter-related infections.

OBJECTIVE: To test the efficacy of the ARROWgard (Arrow International Inc, Reading, Pa) central venous catheter (CVC) coated with silver sulfadiazine and chlorhexidine (A-CVC) in the prevention of CVC-related infections. DESIGN: Prospective, randomized trial. SETTING: A tertiary care medical center. PATIENTS AND INTERVENTION: Two hundred eighty-two patients who required CVC placement were evaluated in this study. Patients were prospectively randomized to receive either a standard CVC (S-CVC) or the A-CVC. Only fresh-stick double- and triple-lumen catheters were studied. MAIN OUTCOME MEASURES: Patients were evaluated for catheter site inflammation, catheter site colonization, local catheter-related infection, and catheter-related septicemia. RESULTS: The 2 groups were matched for age, percentage in the intensive care unit, percentage receiving total parenteral nutrition, percentage with triple-lumen catheters, and duration of catheterization. Rates of catheter site inflammation in the 2 groups were similar (12% vs 10%, S-CVC group and A-CVC group, respectively). The A-CVC was associated with a significantly decreased catheter site colonization rate (49% vs 28%; 43% reduction; P<.001) and local catheter-related infection rate (22.4% vs 5.8%; 74% reduction; P<.001). Rates of catheter-related septicemia were reduced by 41% in the A-CVC group (6.4% vs 3.8%, S-CVC group and A-CVC group, respectively), but this was not statistically significant. CONCLUSIONS: Despite a marked decrease in catheter site colonization and catheter-related infection rates, the A-CVC did not significantly reduce the incidence of catheter-related septicemia. This may be due to a greater pathogenic dependence on catheter hub contamination rather than catheter site colonization or local catheter-related infection, or the relatively short (5.2 days) duration of catheterization in this study.

Anti-Infective Agents, Local↗
PubMed1995

Metabolic function of the isolated perfused rat liver in chronic sepsis.

Significant alterations of liver function have been identified in experimental sepsis including changes in protein and glucose production. The specific changes which are evident in vivo appear to depend upon the specific experimental model and probably represent the relative contribution of hepatocellular function and extrahepatic influences as well as the time course of the septic process. Relatively few studies have focused on function of the whole organ. In an effort to study intrinsic hepatic function during chronic sepsis, control and septic animals (intraabdominal abscess) were studied using the isolated perfused liver model. Basal hepatic oxygen utilization was mildly elevated compared to that in control livers and the oxygen consumption response to a metabolic load was found to be essentially identical to that in control and septic livers. Glucose and albumin production were not substantially different in these two groups. These findings suggest that alterations in liver function following the induction of sepsis may result from extra hepatic factors, since intrinsic liver function appears to be normal.

Albumins↗
PubMed1993

A neutrophil chemotactic factor present in H. pylori but absent in H. mustelae.

This study was designed to compare the capabilities of Helicobacter pylori and Helicobacter mustelae to generate neutrophil chemotactic activity (NCA) in vitro. H. pylori and H. mustelae were grown in parallel cultures under identical conditions. The cultures were washed and transferred to saline solution for 3 hr to avoid detecting nonspecific chemotactic activity from culture media. Supernatants were subjected to size-exclusion HPLC. All peaks from HPLC were collected and assayed for NCA. Peaks having significant NCA were subjected to gel electrophoresis. H. pylori generated 85.9 +/- 1.7% NCA compared to only 41.6 +/- 2.5% for H. mustelae (P < 0.001). The HPLC peak containing the highest NCA from H. pylori revealed a band on gel electrophoresis at approximately 10.5 kDa. This band was not present on gels from H. mustelae. We conclude that H. pylori produces a neutrophil chemotactic factor lacking from H. mustelae. This offers an explanation for the histologic difference between gastritides caused by these organisms.

Chemotactic Factors↗
PubMed1991

Neutrophil chemotaxis in gastric mucosa. A signal-to-response comparison.

This prospective study compares levels of neutrophil chemotactic activity (NCA) in gastric juice to the neutrophil count in gastric biopsies. Sixty-three male patients enrolled in the study and had antral biopsies following collection of gastric juice during esophagogastroduodenoscopy. Biopsies were examined for the magnitude of gastritis, tissue PMN count, and presence of Helicobacter pylori. Secretions were assayed for neutrophil chemotactic activity. Results show an increase in NCA and in tissue PMN counts with increasing severity of gastritis. H. pylori-positive patients had higher levels of NCA and PMN than H. pylori-negative patients. Wide variability in NCA levels preclude a direct correlation between NCA and PMN counts.

Biopsy↗
PubMed1990

A collateral effect of reward predicted by matching theory.

Matching theory describes a process by which organisms distribute their behavior between two or more concurrent schedules of reinforcement (Herrnstein, 1961). In an attempt to determine the generality of matching theory to applied settings, 2 students receiving special education were provided with academic response alternatives. Using a combined simultaneous treatments design and reversal design, unequal ratio schedules of reinforcement were varied across two academic responses. Findings indicated that both subjects allocated higher rates of responses to the richer schedule of reinforcement, although only one responded exclusively to the richer schedule. The present results lend support to a postulation that positive reinforcement may have undesirable collateral effects that are predicted by matching theory (Balsam & Bondy, 1983).

Adolescent↗