An extrapolation procedure for determination of oxygen debt repayment

Summary Repayment of oxygen debt incurred during physical effort is determined by measuring the extra oxygen used above the resting value during a recovery period of 0.5 to 1 h. Since this imposes an additional stress on the experimental subject, an attempt has been made to develop a simple, quick, and accurate method for determining oxygen debt. The method described here is based on the fact that the curve describing recovery is the resultant of two exponential curves, one fast and one slow, the former being complete in less than 3 min. We have derived a mathematical equation by means of which the total oxygen debt measurable over a 60 min period can be extrapolated from the measurements of excess oxygen consumption over the resting value at the end of 3, 6, and 9 min of the recovery period. The equation has been validated by observations on 10 young healthy subjects at sea level and at high altitude. The results show that the equation has good predictive value.     

Impact of a hand hygiene educational programme on hospital-acquired infections in medical wards

Improvement in hand hygiene (HH) compliance has been associated with a decrease in the incidence of hospital-acquired infection (HAI) and hospital-acquired methicillin-resistant Staphylococcus aureus (HA-MRSA) infection/colonization. We aimed to evaluate the impact of a multimodal intervention in medical wards on HH compliance, alcohol-based hand rub (AHR) consumption and incidence of HAI and HA-MRSA. A before-after intervention study and an assessment 1 year later were conducted in three internal medicine wards. HH compliance during routine patient care was monitored using the WHO HH observation method. AHR consumption was registered. HAI incidence was actively sought during the PRE and POST periods. HAI risk factors were prospectively recorded and incidence density was calculated. A total of 825 patients were prospectively followed in the PRE period and 868 patients in the POST period. We observed 1531 opportunities for HH in PRE and POST periods and 450 1 year later. HH compliance improved from 54.3% to 75.8% (p 0.005) and remained 75.8% at follow-up. AHR consumption increased from 10.5 to 27.2 L/1000 hospital-days and 31.5 L/1000 hospital-days at follow-up. Incidence density of HAI was 6.93 and 6.96/1000 hospital-days in the PRE and POST intervention periods, respectively. HA-MRSA incidence density was 0.92 in the PRE period vs. 0.25/1000 hospital-days in the POST period (p 0.2) and 0.15/1000 hospital-days (p 0.1) 1 year later. A sustained increase in AHR consumption was followed by an improvement in HH compliance after a multimodal campaign. A trend for lower incidence density of new hospital-acquired MRSA was detected in the POST intervention and follow-up periods.     

Fast food consumption counters the protective effect of breastfeeding on asthma in children?

Background Fast food consumption and childhood asthma have rapidly increased in recent decades. During the same period there has been an increased rate of prolonged breastfeeding. Objective To evaluate if fast food consumption was associated with asthma in children, and if the proposed protective effect of breastfeeding on asthma was altered by fast food consumption. Methods This case–control study included 246 children with allergist‐diagnosed asthma and 477 non‐asthmatic controls at age 8–10 years. Information on fast food consumption and exclusive breastfeeding was obtained from questionnaire data. The association between asthma and fast food consumption was evaluated. Asthma in relation to exclusive breastfeeding was also evaluated, taking into account fast food consumption as a modifying factor. Results Children with asthma were more likely to consume fast food than children without asthma [crude odds ratio (OR) 1.70, 95% confidence interval (CI) 1.23–2.34]. In comparison to prolonged exclusive breastfeeding (12 weeks), asthma was positively associated with short‐term exclusive breastfeeding (<12 weeks) in children who never or occasionally consumed fast food (crude OR 1.84, 95% CI 1.09–3.11), but not in children who frequently consumed fast food (crude OR 1.07, 95% CI 0.72–1.61). The P‐value for this interaction (0.109) was borderline. Children with high fast food consumption who were exclusively breastfed <12 weeks as infants, had greater than a twofold risk of asthma compared with infants who had been exclusively breastfed for a longer time period and who did not become high consumers of fast food in later childhood. These findings were not affected after final adjustment of confounders and covariates. Conclusion Fast food consumption is associated with asthma in children and potentially counteracts the protective effect of prolonged breastfeeding on asthma. This may explain the paradoxical phenomenon of parallel increased rates of prolonged breastfeeding and asthma in children.     

Emergence of fluconazole resistance in a Candida parapsilosis strain that caused infections in a neonatal intensive care unit

Candida parapsilosis is an increasing cause of bloodstream infections (BSIs) in neonatal intensive care units (NICUs). It has been a persistent problem in the NICU of Hospital for Children and Adolescents, Helsinki University Central Hospital, Helsinki, Finland, since 1987. Fluconazole prophylaxis has been used to control the problem. The number of new infections has, however, increased markedly since September 2000. We assessed fluconazole consumption and occurrence of all Candida species in the NICU from 1991 to 2002. C. parapsilosis bloodstream isolates obtained in the NICU from 1990 to 2002 (n = 26) were genotyped and their fluconazole susceptibility was defined. A low rate of C. parapsilosis BSIs was correlated with high rates of consumption of fluconazole. No emergence of Candida species with primary resistance to fluconazole was detected. However, genotyping with a complex DNA fingerprinting probe revealed that a single strain of C. parapsilosis with decreasing susceptibility to fluconazole was responsible for cross-infections that caused BSIs in the NICU over a 12-year period. The emergence of fluconazole resistance in that strain was observed after more than 10 years of fluconazole prophylaxis.     

Breast cancer and diet in Spain.

Breast cancer is the foremost cause of cancer death in women. A possible relationship has been suggested between breast cancer and cholesterol-rich diets, although no clear link has been established till now. This is an epidemiological study of the evolution of breast cancer mortality in Spain during the period 1977 to 1985, and it was made in relation to the principal dietary components of this country. The study period involved has made it necessary to take into account the corresponding changes in demographic structure; thus, standardization or specific fitting permitted comparisons. Global energy consumption in Spain is under 150 kcal per person per day for 50% of the population, and less than 180 kcal per person per day for 98% (range: 140 to 162) during the study period involved. Low correlation values were observed in relating mean breast cancer mortality rates for the 50 Spanish provinces to the dietary components studied. However, the most significant correlations relate mean mortality rate to total lipids, fiber, cereals, and Vitamin C intake.     

Characterization of a method for quantitating food consumption for mutation assays in Drosophila.

Quantitation of food consumption is necessary when determining mutation responses to multiple chemical exposures in the sex-linked recessive lethal assay in Drosophila. One method proposed for quantitating food consumption by Drosophila is to measure the incorporation of 14C-leucine into the flies during the feeding period (Thompson and Reeder: Environmental Mutagenesis 10:357-365, 1987). Three sources of variation in the technique of Thompson and Reeder have been identified and characterized. First, the amount of food consumed by individual flies differed by almost 30% in a 24 hr feeding period. Second, the variability from vial to vial (each containing multiple flies) was around 15%. Finally, the amount of food consumed in identical feeding experiments performed over the course of 1 year varied nearly 2-fold. The use of chemical consumption values in place of exposure levels provided a better means of expressing the combined mutagenic response. In addition, the kinetics of food consumption over a 3 day feeding period for exposures to cyclophosphamide which produce lethality were compared to non-lethal exposures. Extensive characterization of lethality induced by exposures to cyclophosphamide demonstrate that the lethality is most likely due to starvation, not chemical toxicity.     

Stimulation of lateral hypothalamus during sickness attenuates learned flavor aversions

After rats consumed a flavored substance and were made sick, the experimental animals pressed a lever for 15–20 min to obtain electrical stimulation of the lateral hypothalamus (LH). Although symptoms of sickness were apparent for at least an hour after the stimulation period ended, these rats subsequently drank substantially more of the substance that had been paired with sickness than did control rats that were otherwise similarly treated but not stimulated. When the period of stimulation was interpolated between consumption and sickness, the subsequent consumption of the flavored substance did not differ in stimulated and unstimulated rats. Thus, LH stimulation attenuated the learned flavor aversions by modifying the sickness experience.     

The effect of ambient temperature upon post-natal changes in oxygen consumption of the guinea-pig

1. The effect of thermal environment and administration of progesterone upon minimal oxygen consumption and thermal stability of the new-born guinea-pig has been investigated.

2. It was found that the ambient temperature at which the new-born is reared does not influence minimal oxygen consumption although it modifies the response to cold.

3. Thermal stability was decreased in animals raised in a warm environment.

4. Minimal oxygen consumption per unit body weight during the neonatal period increased 25%, most of the increase taking place within 16 hr after birth.

5. Decrease in the relative mass of brown adipose tissue was least in new-borns maintained at a high ambient temperature.

6. Administration of progesterone did not affect oxygen consumption, body temperature and thermal stability of the new-born.

     

Role of selenium depletion in the etiopathogenesis of depression in patients with alcoholism [corrected

Chronic heavy alcohol consumption adversely affects both macronutrients and micronutrients. Alcohol use affects selenium status. Considerable evidence suggests that selenium status may modify mental function. The author suggests that the effects of alcohol intake on mood, behavior, and cognition may be partly mediated by biological changes related to selenium deficiency.It has been observed that there is a trend towards the normalization of selenium levels in patients with alcoholism after a relatively short period of abstinence from alcohol. It has also been observed that when depression develops in persons with alcoholism, they are likely to improve fairly rapidly after a relatively short period of abstinence from alcohol without therapy aimed at the depressive symptoms. The author suggests that improvement in depressed patients after a period of abstinence from alcohol might be in part related to the normalization of selenium status.Treatment and prevention of comorbid alcoholism and mood disorders require more attention by research workers, practicing physicians, and the general public. Future studies of the etiology and pathogenesis of mood disorders in patients with alcoholism are merited.     

Increase in alcohol related deaths: is hepatitis C a factor?

AIM: To evaluate recent trends in alcohol related deaths in the UK and to consider possible causative factors. DESIGN: Observational retrospective study of the database of the Office for National Statistics, alcohol consumption data reported by the General Household Survey, and other published data. SETTING: England, 1993-9. RESULTS: Deaths for each million of the population from alcohol related illness increased by 59% in men and 40% in women over the years 1993 to 1999. One subgroup of alcohol related deaths, ICD 571.3 (alcoholic liver damage unspecified), showed a 243% increase in men aged 40 to 49 years over the same period. Figures for younger men, and women in all age groups, showed less pronounced increases. There has been no associated rise in alcohol intake. There has been an increase in the incidence of hepatitis C virus (HCV) infection in recent years, and alcohol consumption in HCV positive individuals accelerates the progression to cirrhosis. Circumstantial evidence links the rise in HCV infection to the use of illicit drugs in the 1970s and 1980s, among those currently aged 40 to 59 years. CONCLUSIONS: The recent increase in alcohol related deaths cannot be solely explained by a change in drinking habits. It is suggested that this probably results from the rapid progression of alcoholic cirrhosis in people who have acquired HCV infection through intravenous drug use. Alcohol consumption in HCV positive individuals is firmly linked with a poor outcome.     

Intracellular kinetics of ATX-S10.Na(II) and its correlation with photochemical reaction dynamics during a pulsed photosensitization process: effect of pulse repetition rate

Although photodynamic therapy with pulsed light excitation has interesting characteristics, its photosensitization mechanism has not been fully elucidated. In this study, we showed that the intracellular kinetics of ATX-S10.Na(II), a lysosomal sensitizer, was closely related to photochemical reaction dynamics during photodynamic treatment of A549 cells with nanosecond pulsed light. Fluorescence microscopy revealed that at high frequencies of 10 and 30 Hz the sensitizer initially localized mainly in lysosomes but that it started to be redistributed to the cytosol in certain ranges of radiant exposures. These ranges were found to coincide with a regime of fluorescence degradation with limited oxygen consumption. On the other hand, at 5 Hz, there was no such a discontinuous behavior in the sensitizer redistribution characteristics throughout the period of irradiation; this was consistent with the fact that no reaction switching was observed. Two possible reasons for the appearance of the regime with limited oxygen consumption are discussed: participation of an oxygen-independent reaction and change in the microenvironment for the sensitizer caused by lysosomal photodamage. The pulse frequency-dependent intracellular kinetics of the sensitizer also explains our previous results showing higher cytotoxicity at 5 Hz than at 10 and 30 Hz.     

Alcohol consumption and the risk of self-reported perennial and seasonal allergic rhinitis in young adult women in a population-based cohort study

Background Alcohol consumption has been suggested to be associated with the development of allergic rhinitis (AR), but there is limited data on the topic.
Objectives The objective of this study was to investigate the association between alcohol consumption and the risk of developing AR among young women.
Methods Five thousand eight hundred and seventy Danish women aged 20–29 years participated in a prospective cohort study, and were free of seasonal and perennial AR at baseline (1991–1993). Alcohol consumption was assessed by a food frequency questionnaire. The main outcome measures were self-reported information on seasonal and perennial AR debuting during a mean follow-up period of 7.8 years.
Results During follow-up, 831 women developed seasonal AR and 523 women developed perennial AR, corresponding to 14% and 9%. Alcohol consumption was positively associated with the risk of developing perennial AR. The adjusted odds ratio (OR) for perennial AR was 1.78 (95% CI, 1.13–2.80) among women drinking more than 14 drinks/week compared with women drinking <1 drink/week. There was no association between alcohol consumption and seasonal AR. Having one or two parents with asthma was, after adjustment, significantly associated with the risk of developing seasonal (OR, 2.01; 95% CI, 1.65–2.45) and perennial AR (OR, 2.28; 95% CI, 1.70–2.74). Smoking was not associated with an increased risk of developing AR.
Conclusion In this population of young adult women, alcohol consumption was associated with an increased risk of developing perennial AR.     

Effect of opium addiction on lipid profile and atherosclerosis formation in hypercholesterolemic rabbits

In some Asian and Middle Eastern societies, opium consumption has traditionally been regarded as a way to lower blood lipids and to prevent heart diseases. This could eventually lead to addiction.In this study, the effect of oral opium consumption on serum lipids and atherogenesis in rabbits was investigated.Twenty-eight male New Zealand white rabbits were divided into control, hypercholesterolemic, addicted, and hypercholesterolemic-addicted groups and were studied for 3 months. Serum lipid profile was determined at the beginning of the study and at 1 month intervals thereafter. At the end of the study period, aortic plaque formation was assessed.Compared with control, in the hypercholesterolemic and hypercholesterolemic-addicted groups, cholesterol, triglycerides, and low-density lipoprotein cholesterol levels were significantly increased (P<0.01). The increases in lipids and lesion areas in the aorta were higher in hypercholesterolemic-addicted than hypercholesterolemic group (P<0.05).Our findings suggest that opium consumption can have aggravating effects in atherosclerosis formation related with hypercholesterolemia, mainly affecting lipid profile.     

The influence of penbutolol and placebo on blood sugar levels and insulin consumption in the glucose-controlled insulin infusion system (“Artificial endocrine pancreas”)

Summary The aim of the study was to investigate the influence of 40 mg of the beta-blocker penbutolol (BetapressinTM; Hoechst Ltd., Frankfurt/ Main) in comparison to placebo on the insulin consumption on the blood sugar profile in twelve insulin-dependent diabetes (IDDM) patients. The patients were treated with penbutolol and placebo for a period of three days, and then were examined with the help of the glucose-controlled insulin infusion system.The blood sugar profile and insulin consumption over a 24 hour period was not affected by either penbutolol or placebo, nor could any changes be measured in these parameters when measured after food intake.After a submaximal exercise load on the bicycle ergometer (1 watt per kg body weight) following an evening meal, no difference could be observed between penbutolol and placebo in the above-mentioned parameters. The same was also true for hormonal parameters as STH, ACTH, cortisol, and catecholamines.These findings demonstrated that medication of penbutolol over a three-day period has no influence on the baseline blood sugar profile and insulin consumption or on insulin consumption after food intake during rest and physical exercise.Abbreviations IDDM insulin-dependent diabetes - STH somatotropic hormone - GH growth hormone - ACTH adrenocorticotropic hormone - HbA1 glycosylated hemoglobin A1 - mE milli-units - SEM standard error of the mean     

Reduction of the volume of the sexually dimorphic nucleus of the preoptic area by in utero ethanol exposure in male rats

Ethanol consumption during pregnancy has been demonstrated to result in alterations in central nervous system structure and function. Albino female rats were given either a liquid diet containing ethanol (5% w/v), a liquid diet which contained maltose-dextrin substituted isocalorically for the alcohol, or laboratory chow and water throughout pregnancy and for 14 days following birth. The volumes of the sexually dimorphic nucleus of the preoptic area (SDN-POA) and the nucleus accumbens septi (ACN) were measured in adult male rats exposed in utero and postnatally to these diets. Adult male rats exposed to ethanol in utero exhibit significantly smaller SDN-POA volumes (P less than 0.02) when compared to those of animals which received the control diets during the gestational period and postnatally. Ethanol treatment did not significantly influence the volume of the ACN. The results indicate that maternal ethanol consumption during pregnancy retards or inhibits SDN-POA development in fetal ethanol exposed male rats when compared to the nuclear volume in rats whose mothers were not exposed to ethanol during pregnancy.     

Studies on the Mechanism of Shock: Thermoregulation During Limb Ischaemia

The effect of changes in environmental temperature (4·7-30°) on the rate of O₂ consumption of rats during a period of bilateral hind-limb ischaemia produced by tourniquets has been investigated. Unlike previous experiments on rats after limb ischaemia, while the tourniquets were in place O₂ consumption was increased at environmental temperatures between 30° and 10°. Over this ambient temperature range the slope of the regression line for O₂ consumption on environmental temperature axis was greater than in the controls, but their intercepts on the temperature axis were the same, indicating that the effect was mainly due to decreased insulation. This was attributed to the postural effects of the tourniquets. The results show that during limb ischaemia in 20° acclimated rats when shivering thermogenesis is inhibited, a demand for extra heat can be met by increased non-shivering thermogenesis. Previous work has shown that after removal of the tourniquets, the situation is different as then both shivering and non-shivering thermogenesis are inhibited. These findings are discussed from the point of view of thermoregulation in normal and injured rats.     

Paranatal oxygen consumption and respiratory frequency in the Laysan Albatross

The oxygen consumption and respiratory frequency of Laysan Albatross eggs were measured during the different phases of pipping (paranatal period) and in hatchlings. The initial phase of pipping--penetration of the aircell of the egg by the embryonic beak--coincided with the beginning of pulmonary ventilation, the embryo rebreathing aircell gas, but it did not result in a statistically significant increase in oxygen consumption. The second phase of pipping--star-fracture of the shell (external pipping)--was the shortest (25 h) of the three phases of pipping, and it did not result in a significant increase in either oxygen consumption or respiratory frequency. The longest phase of pipping (65 h)--the pip-hole phase--represented 54% of the total duration of pipping, and it was accompanied by significant increases in oxygen consumption and respiratory frequency. When the eggs hatched, the oxygen consumption increased further but respiratory frequency diminished significantly. It was calculated that the paranatal period, which represented 7.9% of the total incubation period of the egg, accounted for 37.2% of the total oxygen consumption of the egg.     

The Complexity of Alcohol Drinking: Studies in Rodent Genetic Models

Risk for alcohol dependence in humans has substantial genetic contributions. Successful rodent models generally attempt to address only selected features of the human diagnosis. Most such models target the phenotype of oral administration of alcohol solutions, usually consumption of or preference for an alcohol solution versus water. Data from rats and mice for more than 50 years have shown genetic influences on preference drinking and related phenotypes. This paper summarizes some key findings from that extensive literature. Much has been learned, including the genomic location and possible identity of several genes influencing preference drinking. We report new information from congenic lines confirming QTLs for drinking on mouse chromosomes 2 and 9. There are many strengths of the various phenotypic assays used to study drinking, but there are also some weaknesses. One major weakness, the lack of drinking excessively enough to become intoxicated, has recently been addressed with a new genetic animal model, mouse lines selectively bred for their high and intoxicating blood alcohol levels after a limited period of drinking in the circadian dark. We report here results from a second replicate of that selection and compare them with the first replicate.     

Exercise, oxidative stress and ageing

Skeletal muscle has the unique ability to increase the rate of oxygen usage during contraction. This has led several workers to suggest that by-products of this increased oxygen consumption, oxygen-derived free radicals, may be primarily responsible for exercise-induced damage to skeletal muscle. However, because of this rapidly changing redox state, skeletal muscle has developed a number of different endogenous mechanisms which adapt rapidly following a period of exercise. These include numerous structural and biochemical changes such as increased muscle activity of antioxidant enzymes and content of stress or heat shock proteins (HSPs). This adaptation is associated with protection against the potentially damaging effects of a second period of exercise. In addition, we have recently demonstrated a significant increase in free radical production during a period of nondamaging exercise, which is rapidly followed by a significant increase in the expression of antioxidant enzymes and HSPs, suggesting that a change in redox state of the muscle may act as signal for adaptation.     

The mediterranean lecture: wine and thrombosis--from epidemiology to physiology and back

The protective effect of moderate alcohol consumption on the risk of cardiovascular disease has been consistently shown in many epidemiological studies. Antiatherogenic alterations in plasma lipoproteins, particularly increase in high-density lipoprotein (HDL) cholesterol,are considered as the most plausible mechanism of the protective effect of alcohol consumption on coronary artery disease (CHD). Other potential mechanisms contributing to the cardio-protective effects of moderate alcohol consumption include anti-thrombotic down regulation of blood platelet function, as well as of the coagulation and fibrinolysis balance. Since the proposal of a "French paradox" in the early Nineties, the possibility that consuming alcohol in the form of wine might confer a protection against CHD above that expected from its alcohol content, has made the topic"wine and health" increasingly popular. Many epidemiological studies have explored such a possibility, by comparing specific alcoholic beverage types (wine,beer, liqueur) in respect to their relative capacity to reduce the risk of CHD. In parallel, experimental studies have been done, in which wine and wine-derived products have been tested for their capacity to interfere with molecular and cellular mechanisms relevant to the pathogenesis of CHD. Wine might indeed conceivably have other ethanol unrelated beneficial effects. The biological rationale for such a hypothesis has been linked to the enrichment in grape-derived, non-alcoholic components, that possibly make it peculiar in respect to other alcoholic beverages. In fact, while the mechanisms underlying the effects of alcohol on cardiovascular disease have been limited to lipid metabolism and the haemostatic system, those related to wine consumption have also been extended to specific anti-inflammatory, antioxidant and nitric oxide related vaso-relaxant properties of its polyphenolic constituents. The effect of wine consumption has been carefully investigated to account for potential confounding of several conditions (inappropriate use of abstainers as control population, correlation between wine or total alcohol consumption and markers of healthy lifestyle and socioeconomic factors, diet, etc.). Strong evidence indicates that moderate wine consumption rather than confounders reduces both fatal and non fatal CHD events. In spite of the fact that the healthy effect of moderate intake of wine is by now well accepted, important issues remain to be resolved about the relationship between wine, alcohol and alcoholic beverages, the (possibly different) optimal amount of alcohol intake in men and women, the individual or environmental modulation of the alcohol related effect and the pattern of drinking. Some of these issues have been recently addressed in a large meta-analysis, in which the relationship between wine or beer consumption and CHD risk was quantitatively evaluated. We shall summarize here the experimental and epidemiological studies with wine or wine-derived products aimed at finding biological explanations for the supposed superior cardio-protective effects of wine consumption and to discuss some open questions about wine and vascular disease as approached in epidemiological studies.