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Biomedical subjects

J I Blenkharn

Publications and source records attributed to J I Blenkharn.

At least 37 records · Page 2Linked to original sources

Comparative in vitro activity of daptomycin (LY146032) and vancomycin against gram-positive cocci determined using a pharmacokinetic model.

The activity of daptomycin (LY146032) and vancomycin was compared for methicillin-sensitive and methicillin-resistant (MRSA) strains of Staphylococcus aureus and for Enterococcus faecalis, using a semi-automated model that allows examination of time-kill curves with diminishing drug concentrations, thus reflecting in vivo pharmacokinetics. Exposure to daptomycin resulted in rapid killing of all strains of staphylococci and Enterococcus faecalis tested. Methicillin-sensitive staphylococcal strains appeared marginally more susceptible than MRSA. By contrast, the activity of vancomycin appeared much reduced. For all strains, greater than 90% kill was not observed within 24 h. Enterococcus faecalis was uniformly less susceptible to both agents than were staphylococci. The results suggest that despite similar values for MICs, the activity of daptomycin against strains of Staphylococcus aureus and Enterococcus faecalis is comparable to and may exceed that of vancomycin, although the significance of such differences is uncertain.

Daptomycin↗

Nonoperative approach to hilar cancer determined by the atrophy-hypertrophy complex.

Twenty-seven of 135 patients with malignant hilar stricture who had associated liver atrophy or hypertrophy or both were treated by the percutaneous insertion of an endoprosthesis in the hypertrophied lobe only. The procedure was successful in 25 patients. Three patients died within 30 days of drainage. Procedure-related nonfatal complications occurred in seven patients. Effective decompression was accomplished in 21 patients, with complete relief of jaundice in 15. Late complications were experienced by 10 patients. The median total hospital stay was 22 days. Thirteen patients survived from 6 weeks to 12 months (median 5 months), 8 were alive from 3 to 18 months (median 8 months), and 1 patient was lost to follow-up. On the available evidence, we suggest that the preoperative demonstration of the atrophy-hypertrophy complex in jaundiced patients with irresectable hilar cancer is an indication for nonoperative therapy. Patients without the atrophy-hypertrophy complex and those with the complex but associated nonneoplastic disease are likely to fare better with surgical decompression and direct mucosa-to-mucosa anastomosis.

Adenoma, Bile Duct↗

Infection risks from electrically operated breast pumps.

Using formula milk seeded with Staphylococcus epidermidis as indicator, bacteria were observed to pass beyond the collecting bottles of three electrically operated breast pumps. Bacteria were recovered from sites distal to the level of visible contamination, the incidence increasing with repeated use of the apparatus. Despite use of a sterile collecting bottle, retrograde contamination of freshly collected milk may occur from previously contaminated components of the pumps. The results suggest that a terminal in-line air filter is essential to ensure aerosols containing potentially pathogenic bacteria do not contaminate the suction source or be emitted to the environment with the exhaust air. Where a single pump is used by more than one person adequate sterilization of all removable components is essential.

Cross Infection↗

Emission of viable bacteria in the exhaust flue gases from a hospital incinerator.

The exhaust gases from an oil-fired hospital waste incinerator were examined during normal incinerator operation. The design-specified operating temperature was 800 degrees C in the primary combustion chamber and 1000 degrees C in the secondary chamber. Flue gas temperatures, measured from the sampling point at the base of the exhaust stack, varied over the range 186-305 degrees C, and bacteria were recovered from this position in numbers up to 400 cfu m-3 (mean 56 cfu m-3). No sampling was performed at the top of the stack where flue gases were discharged to the atmosphere. Isolates were predominantly gram positive, i.e. Bacillus spp., coagulase negative staphylococci and Staphylococcus aureus, although low numbers of gram negative species (Pseudomonas fluorescens and other pseudomonads) were also recovered. Our results suggest that incineration may not constitute an absolute method of sterilization for clinical waste.

Air Pollutants↗

Intra-abdominal sepsis after hepatic resection.

One hundred and thirty hepatic resections performed over an 8-year period were reviewed for evidence of postoperative intra-abdominal sepsis. Of 126 patients who survived for more than 24 hours after operation, 36 developed culture positive intra-abdominal collections (28.6%). Significant independent variables associated with the development of intra-abdominal sepsis were diagnoses of trauma or cholangiocarcinoma, and the need for reoperation to control hemorrhage during the postoperative period. Before 1984, infected fluid collections were treated predominantly by operative drainage, but this has largely been replaced by percutaneous methods, which have proven effective in most cases. Eighteen (50%) of the infections were caused by a mixed bacterial culture, with Streptococcus faecalis, Staphylococcus epidermidis, Staphylococcus aureus and Escherichia coli being the most common isolates. Six patients with clinical signs of sepsis had a sterile fluid collection drained with complete relief of symptoms. This review suggests that intra-abdominal sepsis is a frequent complication after hepatic resection, and can often be managed successfully by nonoperative percutaneous drainage.

Abdomen↗

Safety devices to prevent airborne infection from clinical suction apparatus.

Infection related to clinical suction apparatus has been widely recognized. Safety systems available at present include devices to prevent overflow from collecting vessels and in-line air filters. The relative efficiency of these devices for the containment of aerosols generated within the collecting vessel has been evaluated. Although of increased resistance, filter capsules of 0.3-micron pore size prevented the passage of test aerosols for longer periods than the widely used 8-micron fibre filter tubes. Filter life can be prolonged by preventing overflow from collecting vessels and protecting against the passage of foam and froth.

Aerosols↗

Endotoxemia in obstructive jaundice. Observations on cause and clinical significance.

Perioperative endotoxemia was detected in 24 of 40 patients who underwent operation for obstructive jaundice (bilirubin level greater than 5.8 mg/dl). Endotoxemia was associated with an increased admission serum bilirubin level (p less than 0.05) and white blood cell count (p less than 0.05) and a decreased hematocrit value (p less than 0.05), but there was no significant association with other established preoperative risk factors. Patients with preoperative endotoxemia had a decreased immunoglobulin M anti-J5 endotoxin titer (p less than 0.05) and a decreased serum bile acid concentration (p less than 0.05). Preoperative endotoxemia was associated with reduced creatinine clearance before and after operation (p less than 0.05). There was no association between endotoxemia and clinical sepsis, gram-negative infection, or small-bowel colonization. Patients who died had increased preoperative serum fibrin degradation products (p less than 0.05).

Cholestasis↗

Sustained anti-adherence activity of taurolidine (Taurolin) and noxythiolin (Noxyflex S) solutions.

Taurolidine (2% w/v) and noxythiolin (1% w/v and 2.5% w/v) solutions inhibit the adherence in-vitro of Escherichia coli and Staphylococcus aureus to human epithelial and fibroblast cells. This effect, demonstrable after 30 min exposure of cells to test drugs, persists after removal of the active compound. Significantly reduced adherence of bacteria is apparent for 5 h after taurolidine treatment and for 6 h after treatment with 2.5% noxythiolin. Anti-adherence activity of taurolidine and noxythiolin may contribute to the observed clinical efficacy of these agents.

Anti-Bacterial Agents↗

Renal impairment following biliary tract surgery.

Postoperative mortality has been directly attributed to renal failure in approximately 5 per cent of patients after surgery for obstructive jaundice. An analysis of 334 patients undergoing biliary tract surgery was undertaken to identify the perioperative factors associated with the development of renal impairment, and to estimate the contribution of renal failure to mortality. Thirty-eight patients (11 per cent) developed postoperative renal impairment (a two-fold increase in serum creatinine postoperatively or a rise of greater than 100 mumol/l). Ninety-three factors were examined in these and 196 control patients. Stepwise logistic regression analysis identified only three factors which were significantly associated with renal impairment: postoperative sepsis (P less than 0.0005), pre-operative serum bilirubin (P less than 0.0005), and pre-operative urea (P less than 0.05). Renal impairment developed at a median 4 days after surgery and was associated with a median of two additional major postoperative complications, particularly sepsis and haemorrhage, for which 17 patients underwent reoperation. Twenty-eight (74 per cent) of the patients with renal impairment died in hospital, but in only one case was the cause of death directly related to renal failure. Twenty patients received specific therapy for renal failure, but only one of these survived. Pre-operative obstructive jaundice and postoperative infection are the major factors associated with renal impairment after biliary tract surgery. Renal impairment appears to be related to postoperative complications rather than directly to the surgical procedure itself. The development of postoperative renal impairment predicts a low chance of survival but appears to be an indicator, rather than a direct cause of a poor prognosis.

Acute Kidney Injury↗

A new safety system for air filtration in clinical suction apparatus.

The design and development of a low cost differential pressure indicator giving continual pressure comparison across the substance of an air filter is described. A hazard warning is given when the differential pressure rises above a pre-set value proportional to significant loss of filter efficiency. The differential pressure indicator affords increased protection against infection associated with the use of suction apparatus and allows a net saving in expenditure by ensuring optimum use of integral air filters.

Cross Infection↗

A low-cost antifoam additive for agar-based culture media.

A highly effective, low-cost silicone-based antifoam emulsion is described which, at a final concentration of 100 ppm, prevents bubble formation during the preparation and dispensing of agar media. The compound is heat-stable, has a long shelf-life and offers considerable savings in cost by reduction in wastage of time and materials. It has no demonstrable deleterious effect on the growth of a wide range of pathogenic and commensal bacteria, or on antibiotic disc susceptibility testing, when examined using a range of different media.

Anti-Bacterial Agents↗

The differential cytotoxicity of antiseptic agents.

The cytotoxicity of the antiseptic agents noxythiolin and chlorhexidine has been evaluated in-vitro using a range of tissue culture cell lines of differing degrees of neoplasticity. Noxythiolin appeared more cytotoxic than did chlorhexidine when tested against established neoplastic cell lines. By contrast, noxythiolin was not cytotoxic to normal control (non-neoplastic) cells. For chlorhexidine, the cytotoxic activity against control cells was similar to that observed for neoplastic cell lines. The results confirm an earlier observation of limited antitumour activity of noxythiolin solutions and, on the basis of differential cytotoxicity, confirm that noxythiolin is free from adverse effects against normal tissues and is safe for use as an antimicrobial agent applied to peritoneal surfaces and the healing wound.

Anti-Infective Agents, Local↗