Vitamin E suppresses increased lipid peroxidation in cigarette smokers

Cigarette smoke contains many xenobiotics, including oxidants and free radicals, which can increase lipid peroxidation. Recently, breath pentane output (BPO) has been recognized as a good indicator of lipid peroxidation. Vitamin E is known to be a potent free radical scavenger which can protect biological membranes against oxidative damage. We investigated the effect of vitamin E (dl-alpha-tocopherol) on lipid peroxidation in 13 healthy smokers. The results showed (1) smokers had increased BPO as compared with 19 healthy non-smokers (16.3 +/- 1.9 vs 5.8 +/- 0.5, pmol/kg body weight/min, p less than 0.001) although both groups had comparable plasma vitamin E and selenium concentrations, (2) supplementation with vitamin E (800 mg/day for 2 weeks) decreased BPO in smokers, and (3) the concentration of plasma selenium-dependent glutathione peroxidase was restored to normal in those smokers (five out of 13) in whom this was low initially. We conclude that a normal plasma concentration of vitamin E does not prevent this increase of lipid peroxidation in smokers but that substantial doses of vitamin E will significantly reduce this increased lipid peroxidation. If a major function of vitamin E is to protect lipids from peroxidation, then smokers have a conditioned insufficiency of vitamin E on a normal diet.

Penetration of cefoperazone into ascites

The pharmacokinetics of cefoperazone was studied in eleven cirrhotic patients with ascites after i.v. administration of a single dose of 15 mg.kg-1 (n = 7) or after three doses of 15 mg.kg-1 given at 12 h intervals (n = 4). The concentrations of cefoperazone in serum and ascitic fluid were determined by HPLC. The peak serum cefoperazone concentration after a single i.v. injection of 15 mg.kg-1 was 96.0 mg.l-1. The serum elimination half-life was longer (5.0 h) than in normal subjects. The penetration of cefoperazone into ascites was satisfactory (32.3% and 58.3% after single and repeated injections, respectively). Ascitic fluid concentrations of cefoperazone exceeded 5.4 mg.ml-1 from 0.5 to 6 h after the single i.v. injection, levels which are well above the MIC of most pathogens found in spontaneous bacterial peritonitis. Adjustment of the dose of cefoperazone in cases of severe hepatic insufficiency does not appear to be necessary provided that renal function is normal.

Methods of disinfecting endoscopic material: results of an international survey

A questionnaire on the methods of cleaning and disinfecting endoscopic equipment was mailed to 120 centers in Western Europe. Seventy-four questionnaires (61%) were returned. The centers were classified into three groups according to the number of endoscopic procedures performed per year. This survey has shown that precautions are more rigid in specialized centers than in units doing fewer than 1,500 endoscopic investigations a year. Complete disinfection is done by almost all the centers after ERCP in infected patients or in the case of HBsAg and HIV-positive patients, but only by 70% of centers after completion of endoscopies performed in patients with gastrointestinal hemorrhage and unknown immunological status. After endoscopic examination performed in presumably non-infected subjects, complete disinfection is not done in any center after gastroscopy, in 13% after colonoscopy and in 30% after ERCP. Continued education of endoscopic personnel and greater availability of adequate endoscopic equipment is mandatory for minimizing the risk of endoscopy-related infections.

Breath alkanes as an index of lipid peroxidation

Formation of free radicals and lipid peroxidation are mechanisms that are involved in many conditions including cellular damage. In a human body, there are many antioxidant systems likely to limit the production of free radicals and to reduce their deleterious effect. The peroxidation of polyunsaturated fatty acids, such as linoleic acid and linolenic acid which are cell membrane components, induces the formation of volatile alkanes that are excreted in the breath. The determination of breath alkanes (pentane and ethane) is considered to be a valuable and elegant method to assess lipid peroxidation. The method for collecting a breath sample and the chromatographic analysis of the collected gas require a strict methodology. Moreover, we must take into consideration some factors, such as the hepatic function, which may influence the pentane metabolism itself. We critically describe the results of breath alkane determination obtained in humans in different clinical conditions.

Breath alkanes as an index of lipid peroxidation

Formation of free radicals and lipid peroxidation are mechanisms that are involved in many conditions including cellular damage. In a human body, there are many antioxidant systems likely to limit the production of free radicals and to reduce their deleterious effect. The peroxidation of polyunsaturated fatty acids, such as linoleic acid and linolenic acid which are cell membrane components, induces the formation of volatile alkanes that are excreted in the breath. The determination of breath alkanes (pentane and ethane) is considered to be a valuable and elegant method to assess lipid peroxidation. The method for collecting a breath sample and the chromatographic analysis of the collected gas require a strict methodology. Moreover, we must take into consideration some factors, such as the hepatic function, which may influence the pentane metabolism itself. We critically describe the results of breath alkane determination obtained in humans in different clinical conditions.

[Non-invasive methods for assessing the small intestines]

Non-invasive methods investigating small bowel functions are critically reviewed. For intestinal absorption, we discuss the value of fecal fat determination, D-xylose testing and breath tests. Intestinal bacterial overgrowth may be assessed by breath hydrogen test or 14C-D-Xylose breath test. Small intestinal transit time can be measured by a scintigraphy method or by a breath hydrogen technique. Intestinal clearance of alpha-1 antitrypsin is now the method of choice for the detection of protein-losing enteropathy. Intestinal permeability can be assessed by 51Cr-EDTA/14C-mannitol ratio or PEG 900 method.

Familial Crohn's disease in multiple siblings: no linkage to the HLA system

We report five families with 3 or more children having Crohn's disease. In one family, 6 out of 11 siblings were affected. HLA haplotype study in affected children showed that the probability of random segregation was only 38 percent, making improbable a linkage between the histocompatibility locus and the development of Crohn's disease. However similar clinical patterns in siblings could suggest a genetic factor not linked to the HLA system.

[Parenteral nutrition at home: 2 years' experience]

Home parenteral nutrition (HPN) must be reserved for patients with an dysfunctional bowel requiring a long-term nutritional support. We report a 2 year experience of HPN at Erasmus Hospital which includes seven patients. Indications and implications of HPN are also discussed.

Increased lipid peroxidation after lipid infusion as measured by breath pentane output

We studied the effect of intravenous lipid infusion on lipid peroxidation as measured by breath pentane. Pentane, plasma alpha-tocopherol (alpha-tox) and plasma gamma-tocopherol (gamma-toc), selenium, and Se-dependent glutathione peroxidase (Se-GSHPx) were measured in 10 normal control subjects and in 10 home parenteral nutrition (HPN) patients before and after infusion of 100 mL Nutralipid 10% over 30 min. Before infusion, breath pentane was significantly higher and alpha-toc was significantly lower in the HPN group than in the control subjects. These two measurements were significantly negatively correlated (r = -0.54, p less than 0.05). Pentane, alpha-toc, and Se-GSHPx were significantly increased in both groups after lipid was infused but were still significantly higher in HPN patients than in control subjects. Thus, infusion of a small amount of lipid rich in linoleic acid induced a significant increase in breath pentane, reflective of increased lipid peroxidation.

Plasma vitamin E and selenium and breath pentane in home parenteral nutrition patients

Because both vitamin E and selenium protect against lipid peroxidation, we evaluated the relationship between breath pentane, evolved from the peroxidation of linoleic acid, and plasma levels of alpha-tocopherol (vitamin E), Se, and Se-dependent glutathione peroxidase (Se-GSHPx). Nine home parenteral-nutrition (HPN) patients received added Se in intravenous solutions and were compared with 10 normal control subjects. The excretion of pentane (pmol.kg-1.min-1, means +/- SEM) in control subjects (6.34 +/- 0.96) was significantly lower than in HPN patients (15.02 +/- 1.12, p less than 0.001). alpha-Tocopherol (mumol/L), Se (mumol/L), and Se-GSHPx (U) values were, respectively, 18.13 +/- 1.70, 1.70 +/- 0.05, and 5.34 +/- 0.27 in control subjects and 10.21 +/- 1.66, 1.35 +/- 0.14, and 7.01 +/- 0.31 in HPN patients. All differences were statistically significant. Significant negative correlations were observed between plasma alpha-tocopherol levels and HPN duration and between pentane output and plasma alpha-tocopherol levels (r = -0.58, p less than 0.01). In HPN patients with reduced plasma alpha-tocopherol levels associated with increased pentane output, there is, inferentially, increased lipid peroxidation despite normal plasma Se and Se-GSHPx levels.

[Villous tumors of the rectum. Endoscopic treatment using photocoagulation]

We report the results of endoscopic photocoagulation in the treatment of villous adenomas of the rectum in 49 consecutive patients (26 males, and 23 females, mean age: 74 years). Twenty-six patients were treated with a high-power Nd-Yag laser (80 W/sec). After a mean of 3.4 laser sessions, all the small-sized adenomas (C1) and 88% of the intermediate-sized adenomas (C2) were healed. No extensive villous adenoma (C3) could be eradicated. Complications occurred in 5 patients. Recurrence was observed in 3 C2 patients who are still on maintenance laser therapy. Twenty-three patients were treated with another Nd-Yag laser (maximal power output: 45 W/sec). After a mean of 6.4 laser sessions, 85% of the C1 patients were healed, while eradication of villous tissues was obtained in 60% of C2 and C3 patients. No complications were noted. A recurrence was observed in three C1 patients with secondary healing after reinstitution of laser therapy in 2 cases. Moreover, two C3 patients also relapsed and laser eradication was again obtained in 1 patient. In conclusion, these results confirm the efficacy of laser therapy in small- and intermediate-sized villous adenomas of the rectum. The number of laser sessions required for eradicating a villous tumour was lower using a high-power Nd: Yag laser, but the risk of complications was increased.

Lipid-associated total parenteral nutrition in patients with severe acute pancreatitis

Biochemical data were studied in 18 patients with severe acute pancreatitis receiving lipid associated with total parenteral nutrition. The mean nonprotein energy intake was 30 kcal/kg/day, with 34-70% of the nonprotein calories as lipid. These parameters were no different between patients who survived and those who died. The mean sum of Ranson criteria was significantly higher in patients who died as compared with those who survived. Plasma triglycerides, glucose, albumin, and the amount of insulin supplementation were related to the severity of the disease and to the outcome. Persistent hypertriglyceridemia, hyperglycemia, hypoalbuminemia, and higher insulin requirements were observed in patients who died in comparison with those who survived and this appeared to be an index of fatal outcome. These abnormalities reflect in part an inability to utilize nonprotein energy, because the measured energy expenditure in relation to intake was lower in the patients who died, despite comparable intakes and expected energy expenditures.

Breath pentane analysis as an index of lipid peroxidation: a functional test of vitamin E status

Pentane, which evolves from the reaction involving omega-6 fatty acids, is a good index of lipid peroxidation. We describe a method for measuring breath pentane excretion in adult humans. After a 4-minute washout period, expired air was analyzed by gas chromatography. Breath was passed through a cooled loop of alumina to adsorb, concentrate, and release, on heating, pentane. Pentane was analyzed by a Porasil-D column with a derived calibration curve. The mean excretion of pentane in 10 normal adults was 6.34 +/- 0.96 pmol X kg-1 X min-1 (mean +/- SEM) and was significantly higher in five patients with plasma vitamin E deficiency (15.39 +/- 1.84 pmol X kg-1 X min-1). There was a significant negative correlation between pentane output and plasma vitamin E levels (r = -0.66, p less than 0.01). Moreover, breath pentane excretion was significantly decreased after a 10-d supplementation with vitamin E in five normal subjects. We conclude that breath pentane output is a sensitive, noninvasive, functional test for assessing vitamin E status.