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Biomedical subjects

D Lambert

Publications and source records attributed to D Lambert.

At least 19 recordsLinked to original sources
PubMed1992

Importance of various antioxidant enzymes for cell stability. Confrontation between theoretical and experimental data.

A theoretical model was developed taking into account the production and destruction of oxygen-derived free radicals. The steady state of the system was derived by using the rate equations of these reactions, and the stability of the system was tested. In the simplified model, only one stable steady state was found. However, we know that glutathione peroxidase can be inhibited by hydroperoxides, and, when incorporated into the model, this effect led to a complex situation with the presence of some stable and some unstable domains according to the concentration of either the enzyme or the hydroperoxide. This qualitative description of the system was compared with experimental data on the protection given by three antioxidant enzymes, and concordance of data was found which allows some quantification of the system. A general view of the efficiency of the three antioxidant enzymes and of the stability of the system according to their concentrations could be produced.

Animals↗
PubMed1992

Prevalence of lower limb ulceration in an urban health district.

Before establishing a community leg ulcer programme, a survey was performed to assess the incidence and prevalence of lower limb ulceration in the Newcastle Health District. The prevalence was 1.9 per 1000 in patients over the age of 45 years, and the annual incidence 3.5 per 1000 in the same age group. Recurrent ulcers represented 47 per cent of the total and 50 per cent of all ulcers had been present for > 6 months. District nurses spent 190 h per week in the community dressing leg ulcers, making a total number of 25,922 visits each year. In the treatment of leg ulcers 35 different types of dressing were used and only 14 per cent of ulcerated limbs were treated by appropriate compression. Of all patients with leg ulcers, 35 per cent had been seen by a hospital specialist but only 7 per cent had been examined by a vascular surgeon at any time.

Aged↗
PubMed1992

Fotemustine plus dacarbazine for malignant melanoma.

119 patients with metastatic melanoma received fotemustine 100 mg/m2 on days 1 and 8 and dacarbazine 250 mg/m2 on days 15-18. After a 5-week rest, fotemustine 100 mg/m2 on day 1 and dacarbazine 250 mg/m2 on days 2-5 was given every 3-4 weeks. 12 complete responses (11.6%) and 16 partial responses were observed in 103 evaluable patients (response rate 27.2%). The median duration of response was 21.5+ weeks (8+ to 53+). The response rate was 26.3% in CNS, 18.2% in visceral sites and 37.5% in non-visceral sites. The toxicity was mainly haematological: grade III-IV leukopenia in 27.4% and thrombocytopenia in 23.4%. The response rate was lower than that in 63 patients previously reported. The present series had a higher median age (54 vs. 40 years) without any differences in other population variables. However, activity on CNS metastases and on non-visceral sites was confirmed. Haematological toxicity was about 50% lower than that with fotemustine alone. Hence, this is an active outpatient regimen for metastatic melanoma, especially against cerebral and non-visceral metastases.

Adult↗
PubMed1992

Measurement of lower oesophageal pH during induction of anaesthesia: use of oesophageal probe.

Gastric contents regurgitation into the oesophagus during induction of anaesthesia may easily fail to be recognized. The incidence of this complication was investigated in 59 consecutive patients. They were scheduled for elective thoracic surgery. Anaesthesia was induced with thiopentone (6 mg.kg-1), fentanyl (3 micrograms.kg-1), and either atracurium (0.4 mg.kg-1), vecuronium (0.1 mg.kg-1) or suxamethonium (1.5 mg.kg-1). Oesophageal pH was monitored with an oesophageal pH probe, connected to a portable computer. The pH probe had a virtually instantaneous response time and was positioned in the lower oesophagus. Acid reflux was defined as a decrease in pH to less than 4.0. During the course of induction, three patients (5%) presented an episode of acid reflux. No patient presented any clinical or radiological signs of pulmonary aspiration. This study suggests that monitoring oesophageal pH is a simple method of detecting gastric reflux during the period of induction.

Adult↗
PubMed1992

Pharmacokinetics and tissue penetration of single-dose cefotetan used for antimicrobial prophylaxis in patients undergoing colorectal surgery.

The pharmacokinetics and tissue penetration of cefotetan were studied after a single injection of 2 g given intravenously for antimicrobial prophylaxis to 16 consecutive patients undergoing colorectal surgery. Concentrations in tissue greater than or equal to the MIC for 90% of the main pathogens tested were considered adequate. The elimination half-life at beta phase was 4.6 +/- 1.4 h, the total body clearance was 0.75 +/- 0.19 ml/kg/min, and the volume of distribution was 260 +/- 71 ml/kg. At the time of incision (33 +/- 16 min after the injection), cefotetan concentrations were 14.2 +/- 7 micrograms/g in abdominal-wall fat, 16.4 +/- 1 micrograms/g in epiploic fat, and 163 +/- 62 mg/liter in serum. At the time of surgical anastomosis (151 +/- 54 min), cefotetan concentrations were 33.3 +/- 6 micrograms/g in the colonic wall and 73 +/- 34 mg/liter in serum. Upon closure of the abdomen (216 +/- 76 min), cefotetan concentrations were 6.3 +/- 3 micrograms/g in abdominal-wall fat, 6.1 +/- 4 micrograms/g in epiploic fat, and 64 +/- 38 mg/liter in serum. Cefotetan tissue penetration was 10% into abdominal and epiploic fat and 46% into the colonic wall. Levels in tissue were compared with the MIC for 90% of the most frequently encountered pathogenic germs (Staphylococcus aureus, Bacteroides fragilis, and Escherichia coli). Adequate concentrations in tissue were obtained up to anastomosis but not upon closure. The authors therefore recommend the injection of an additional dose of 1 g before closure in order to ensure optimal efficacy throughout the surgical procedure.

Cefotetan↗
PubMed1992

[Association of sarcoidosis and Waldenström's macroglobulinemia].

Sarcoidosis is seldom associated with Waldenström's macroglobulinaemia. We report the case of a 58-year old woman, 7 years after cutaneous and pulmonary sarcoidosis had begun, developed Waldenström's macroglobulinaemia. Chlorambucil was effective on both diseases. The possibility of reactive sarcoidotic granulomas in neoplastic diseases may cast doubts on the reality of the sarcoidosis-malignant haemopathy association. However, most authors consider that such associations are not fortuitous and can be explained by the immunological abnormalities observed in patients with sarcoidosis.

Chlorambucil↗
PubMed1991

[Comparison of thrombogenic risk between teflon and polyethylene in prolonged catheterization of the radial artery].

This prospective study was designed to compare the rates of radial artery thrombosis after long-term cannulation with two different types of catheters with similar size. It included 101 patients, randomly assigned to group A (n = 51, 61 +/- 17 years, 80% males), and group B (n = 50, 55.8 +/- 18 years, 54% males). Patients in group A were cannulated with a polyethylene catheter (Leader Cath. 115-09), and those in group B with a Teflon catheter (Plastimed Seldicath). The diagnosis of arterial occlusion was made by way of a bedside angiography performed before catheter removal. An X-ray was taken after injection of 10 to 15 ml Hexabrix through the catheter. The two groups were similar with regard to anthropometric parameters (except for the sex ratio), cannulation technique, used drugs, duration of cannulation, pathological events during the stay in intensive care. The rate of complete arterial thrombosis in the two groups was similar (10%). There were no differences in the rates of partial thrombosis (51 vs. 36%, n.s.) and of absence of thrombosis (39 vs. 54%, n.s.). The rate of arterial thrombosis did not vary with the duration of cannulation, nor with age, sex, systemic heparinization, vascular collapse, cannulation technique. However, 4 polyethylene catheters were infected on removal (coagulase negative Staphylococcus, Pseudomonas aeruginosa) versus only one Teflon catheter (Staphylococcus epidermidis). In conclusion, the biocompatibility of Teflon and polyethylene catheters was found to be similar.

Adult↗
PubMed1991

Dermatitis herpetiformis associated with ulcerative colitis.

Over the past 20-years, it has been shown that the majority of patients with dermatitis herpetiformis (D.H.) suffer from coeliac disease of varying intensity. Dermatitis herpetiformis may also be associated with other autoimmune diseases but only exceptionally with chronic ulcerative colitis (U.C.).

Adult↗
PubMed1991

Ofloxacin pharmacokinetics in mechanically ventilated patients.

The pharmacokinetics of ofloxacin were studied in 12 intensive care patients, 6 of whom were under controlled mechanical ventilation. All patients had a creatinine clearance of greater than 80 ml/min per 1.73 m2. They were given 3 mg of ofloxacin per kg of body weight intravenously at a constant flow rate in 30 min twice a day for 7 days. Pharmacokinetic studies were performed on days 1 and 7. Between days 1 and 7, significant increases in the alpha (distribution) and beta (elimination) phase half-lives, the area under the serum concentration-time curve, and peak and trough levels in serum were observed, together with a marked decrease (greater than 50%) in total body clearance. Possible contributing factors for alteration of ofloxacin pharmacokinetics in ventilated patients were patient age, liver dysfunction, drug interaction, and drug accumulation in a deep compartment. This study shows that in intensive care patients the pharmacokinetics of ofloxacin differ from those reported for healthy volunteers.

Critical Care↗
PubMed1991

Blood transcobalamin levels in malignant hepatoma.

Alpha-Fetoprotein (AFP) levels measured by RIA show a strong sensitivity for the biological diagnosis of malignant hepatoma (MH). However, this parameter lacks specificity. Previous observations of an alteration in vitamin B12 metabolism in the presence of hepatoma led us to study vitamin-B12-binding proteins. Vitamin B12, also called cobalamin, is transported in the blood by two proteins or transcobalamins: one is haptocorrin (HC), which is linked to most of the cobalamin, and the other is transcobalamin II, which is involved in tissue exchanges. In this work, the levels of AFP and transcobalamins were determined by RIA and radioisotope dilution assay, respectively. They were measured in patients with MH (group A) and in patients with other liver diseases (group B). Compared with group B, group A showed a significant increase in total serum HC (p less than 0.005). In conclusion, it was observed that MH is accompanied by increased levels of HC. The origin of these changes could be due to either an increase in HC synthesis or a catabolic defect.

Carcinoma, Hepatocellular↗