Biomedical subjects

M Pettigrew

Publications and source records attributed to M Pettigrew.

4 recordsLinked to original sources

PubMed1993

Comparison of NHS and private patients undergoing elective transurethral resection of the prostate for benign prostatic hypertrophy.

OBJECTIVES: To compare the operative thresholds and clinical management of men undergoing elective transurethral resection of the prostate for benign prostatic hypertrophy in the NHS and privately. DESIGN: Cohort study of patients recruited by 25 surgeons during 1988. SETTING: Hospitals in Oxford and North West Thames regions. PATIENTS: Of 400 consecutive patients, 129 were excluded because of open surgery (nine), lack of surgeons' information (three), and emergency admission (117) and three failed to give information, leaving 268 patients, 214 NHS patients and 54 private patients. MAIN MEASURES: Sociodemographic factors, prevalence and severity of symptoms, comorbidity, general health (Nottingham health profile) obtained from patient questionnaire preoperatively and reasons for operating, and operative management obtained from surgeons perioperatively. RESULTS: NHS and private patients were similar in severity of symptoms and prevalence of urinary tract abnormalities. They differed in four respects: NHS patients' general health was poorer as a consequence of more comorbid conditions (49, 23% v 7, 13% in severe category); the condition had a greater detrimental effect on their lives (36, 17% v 2, 4% severely affected; p < 0.01); private patients received more personalised care more quickly and were investigated more before surgery, (29, 54% v 60, 20% receiving ultrasonography of the urinary tract); and NHS patients stayed in hospital longer (57, 27% v 3, 6% more than seven days; p < 0.001). CONCLUSIONS: Private patients' need for surgery, judged by symptom severity, was as great as that of NHS patients, and there was no evidence of different operative thresholds in the two sectors, but, judged by impact on lifestyle, NHS patients' need was greater.

Comorbidity↗

PubMed1991

Mathematical analysis of perifusion data: models predicting elution concentration.

System models are constructed and analyzed for combined convective flow and for dispersion in distorting concentrations of a chemical signal as it passes through a packed column. We derive general analytical solutions for these models. The results have applications to analyses such as in biological experiments involving hormonal stimulation of perifused cells, elution chromatography, adsorption columns, and studies of groundwater flow. The models reveal that the column distorts an incoming signal (such as a change in solute concentration in the flowing liquid) at the inlet. This distortion is greatest at low values of the Peclet number of the flow and is small at larger values. We explore the effects of the approximations inherent in the mathematical models of the system. Specification of the boundary conditions of the problem are shown to be particularly important. With the use of incorrect models, it is possible to obtain accurate interpolations to data obtained from perfusion experiments. However, the parameters derived (in particular the dispersion constant and the peak concentration of a solute concentration pulse) may be considerably in error. This may lead to errors when these parameter estimates are used to predict results in other experimental situations.

Animals↗

PubMed1990

Effects of daptomycin and vancomycin on tobramycin nephrotoxicity in rats.

Daptomycin is a new biosynthetic antibiotic which belongs to a new class of drugs known as lipopeptides. The objective of this study was to evaluate the effects of daptomycin and vancomycin on tobramycin-induced nephrotoxicity. Female Sprague-Dawley rats were treated during 4 and 10 days with either saline (NaCl, 0.9%) or tobramycin at doses of 4 and 40 mg/kg per day (given every 12 h [q12h] intraperitoneally). Each treatment was combined with saline, daptomycin at a dose of 20 mg/kg per day (given q12h subcutaneously), and ancomycin at a dose of 50 mg/kg per day (given q12h subcutaneously). Daptomycin and vancomycin had no effect on the intracortical accumulation of tobramycin. Daptomycin did not accumulate in renal tissue even after 10 days of treatment. Tobramycin given at a dose of 40 mg/kg per day during 10 days induced a significant inhibition of sphingomyelinase activity in the renal cortex (P less than 0.01) and increased cellular regeneration (P less than 0.01), as measured by the incorporation of [3H]thymidine into DNA of the renal cortex. These changes were minimal when daptomycin was combined with tobramycin. Histologically, signs of tobramycin toxicity were also less severe in the presence of daptomycin. The intracortical accumulation of vancomycin was not modified by tobramycin. The sphingomyelinase activity was significantly more inhibited (P less than 0.01) when vancomycin was associated with tobramycin (4 and 40 mg/kg) without affecting the rate of [3H]thymidine incorporation into DNA. Histologically, signs of tobramycin toxicity were not affected by vancomuycin, but the cellular vacuolizations which were also observed in vancomycin-treated animals were still present in the proximal tubular cells of animals that were treated with the combination vancomycin-tobramycin. This study strongly suggests that daptomycin protects animals from tobramycin-induced nephrotoxicity but that vancomycin may enhance the effect of tobramycin. We conclude that daptomycin is safe and protects kidney cells from tobramycin-induced nephrotoxicity.

Animals↗

PubMed1988

Influence of hydrocortisone on gentamicin-induced nephrotoxicity in rats.

Many risk factors associated with aminoglycoside nephrotoxicity have been identified in humans and experimental animals. They include an initial high rate of creatinine clearance, high initial peak levels in serum, age, sex, duration of therapy, liver disease, and renal infection. The concomitant administration of steroids has never been investigated. We evaluated the role of hydrocortisone on gentamicin-induced nephroxicity in a model of infused rats. We showed that hydrocortisone given over 3 days after the infusion did not modify the gentamicin half-life in the renal cortex, gentamicin-induced lysosomal phospholipidosis, or histopathology but did reduce significantly the 3H/DNA ratio on day 4 after gentamicin infusion. We concluded that hydrocortisone interferes with the postnecrotic cellular regeneration process, an important step that is responsible for the recovery of normal kidney structure following toxic injuries associated with aminoglycoside therapy.

Animals↗