Study of ethane level in exhaled breath in patients with age-related macular degeneration: preliminary study.

PURPOSE: A variety of factors have been implicated in the pathogenesis of age-related macular degeneration (ARMD), and oxidative stress plays an important role in the onset and progression of the disease. Breath ethane is now considered a specific and non-invasive test for determining and monitoring the trend of lipid peroxidation and free radical-induced damage in vivo. This test provides an index of the patients' overall oxidative stress level. We evaluated the breath ethane concentration in exhaled air in patients with advanced ARMD. METHODS: In this study, we enrolled 13 patients with advanced ARMD and a control group, and a breath analysis was carried out by gas chromatography. RESULTS: The mean ethane level in the ARMD patients was 0.82 ± 0.93 nmol/l (range: 0.01-2.7 nmol/l) and the mean ethane value in the control group was 0.12 ± 0.02 nmol/l (range: 0.08-0.16 nmol/l). The difference between the values of the 2 groups was statistically significant (p < 0.005). Receiver operating characteristic analysis showed an elevated area under the curve (0.831; 95% CI: 0.634-0.948), with a significance level of p < 0.0014 (area = 0.5). CONCLUSIONS: These preliminary results seem to indicate that breath ethane levels are higher in most patients with ARMD. The breath ethane test could thus be a useful method for evaluating the level of oxidative stress in patients with ARMD. To our knowledge, there are no data on this type of analysis applied to ARMD.

[Occupational injuries and sickness absence: association with job demand, decision latitude, and life style in 2174 workers in the Veneto Region]. / Infortuni sul lavoro e assenze dal lavoro per malattia: associazioni con carico lavorativo, autonomia decisionale e stili di vita in 2174 lavoratori del veneto.

BACKGROUND: Stress was the most frequent (26,9%) health problem reported in a survey on the perception of working and health conditions in 5000 workers in the Veneto Region. OBJECTIVES: The aim of the study was to investigate in the Veneto Region the association between occupational stress and events occurred in the previous 12 months: occupational accidents, or sickness absence for 10 or more consecutive days. METHODS: Perceived occupational stress is correlated, according to Karasek's model, to high job demand (JD) and low decision latitude (DL). Using Karasek's questionnaire (to which questions on smoking and alcohol consumption were added), we examined 2174 subjects working in 30 companies with between 10 and 500 employees, who belonged to the occupational categories of industry and services that are more prevalent in the Veneto Region. The questionnaire was administered by the occupational physician during health surveillance. The subjects were classified on the basis of current exposure to psychosocial factors or, for subjects reporting an event, their exposure at that time. We identified the tertiles of JD and DL; data were submitted to the analysis of multiple logistic regression, estimating odds ratio (OR) and 95% confidence interval (CI). The population attributable risk (PAR) was calculated using the formula (pc (OR-1)/OR), where pc is the fraction of exposed cases. RESULTS: An elevated risk of occupational accidents was found in subjects with regular consumption of alcohol (OR = 2.0; IC = 1.2-3.5), in smokers smoking 10-20 (2.3; 1.3-3.8) or >20 cigarettes/day (3.8; 1.8-7.9), in the highest tertile of JD (2.29; 1.35-3.89) and in the lowest tertile of DL (1.6; 1.0-2.6). PAR was 37.6% for occupational factors (high JD and low DL), 44.5%for non-occupational factors (cigarette smoking and alcohol consumption), and 82.1% overall. The risk of sickness absence increased in subjects smoking 10-20 cigarettes (1.63 = 1.1-2.40), in the highest tertile of JD (1.5; 1.0-2.2) and in the lowest tertile of DL (1.6; 1.1-2.2). PAR was 26.1% for occupational factors (high JD and low DL), 7.6% for non-occupational factors (smoking), and 30.4% overall. While the risk of sick absence increased mainly with the reduction of DL, the risk of occupational accidents increased with increasing JD and, to a lesser extent, with decreasing DL. The current approach to accident prevention is based only on technical and administrative aspects, in spite of the fact that 80% of accidents are not attributable to malfunctioning of machinery. Injury prevention should address technical, personal and psychosocial risk factors together as a whole.

Omeprazole induces apoptosis in normal human polymorphonuclear leucocytes.

We investigated in vitro apoptosis in human polymorphonuclear neutrophils (PMN) induced by omeprazole. This drug, both in the native (OM) and acidified (OM-HCl) form, is a potent inducer of PMN apoptosis. The effect is time- and dose-dependent. OM-HCl is more efficient than OM in inducing PMN apoptosis. In fact, after 24 h incubation in vitro at 1 x 10(-4) M OM-HCl induces apoptosis in 70% of the cell population compared to 37% induced by OM. Apoptosis induced by both forms of the drug is caspase dependent being significantly reduced by pretreating cells with the caspase 3 inhibitor (DEVDH-CHO). However, some differences in the apoptosis mechanisms between the two forms of the drug seem to exist because PMN treatment with the specific caspase 8 inhibitor (Z-IETD-FMK) only blocks OM-HCl mediated apoptosis. We observed cleavage of caspase 8 only in the cells incubated with OM-HCl while the executioner caspase 3 was activated with both forms of the drug. Furthermore, pretreatment with GM-CSF, a known activator of intracellular survival pathways in PMN, partially protected cells from OM-HCl induced apoptosis but did not contrast the apoptotic effect of OM. Cysteine cathepsin proteases also seem involved in the apoptotic mechanism of both drug forms since the specific inhibitor E64d gave a significant protection. To verify if OM-HCl induced apoptosis was dependent on the sulfenamide bound with the cell sulfhydryl groups we used molecules with thiol groups such as beta-mercaptoethanol (beta-ME) and reduced glutathione (GSH). Reactions of OM-HCl with cellular sulfhydryl groups are strongly involved in both the triggering and evolving phase of the apoptotic mechanism since significant protection from apoptosis was obtained when PMN were pretreated for 1 h with beta-ME (lipid-permeable) or GSH (lipid-impermeable). These results show that OM and OM-HCl induce apoptosis in human PMN and suggest that the second binds the sulfhydryl groups, present on the cell membrane, to then penetrate the cell thus causing a further significant increase in apoptosis. OM-induced PMN apoptosis during the treatment of gastric inflammatory disease could be an advantage for the resolution of the phlogosis state. However, this aspect should be further elucidated to assess the optimal therapeutical regimen for gastric diseases which are related to infective agents.

Effect of two-hour daily hemodialysis and sham dialysis on breath isoprene exhalation.

BACKGROUND: Isoprene, a volatile hydrocarbon produced by the human organism, is currently being extensively investigated because the mechanisms underlying its endogenous origin are unknown and because experiments suggest it is toxic and cancerogenous. Previous reports of increases in breath isoprene concentrations during 4-hour, thrice-weekly hemodialysis, but not during continuous ambulatorial peritoneal dialysis, prompted us to assess the behavior of isoprene in another dialytic modality, i.e., short daily hemodialysis (short DHD). Furthermore, in order to determine whether removal of solutes and/or contact of blood with the dialytic membrane influenced the metabolism of isoprene, we performed a sham short hemodialysis session in a subgroup of 8 patients (sham short HD), i.e., with blood flowing through a dialyzer but without dialysate and ultrafiltration. METHODS: The present study evaluates the effects of a two-hour short DHD and a two-hour session of sham HD on isoprene breath levels, as determined by gas chromatography before, during and after sessions. Parallel analyses of ambient air and monitoring of blood pressure and heart rate were performed. RESULTS: Both short DHD and sham DHD induced an increase in breath isoprene exhalation in all patients without being associated with significant hemodynamic variations. CONCLUSION: These findings suggest that the increase in breath isoprene after a session of hemodialysis is neither a reaction to mevalonate depletion nor to metabolic variations induced by the depurative effect, because these changes do not occur during sham HD. It is not related to hemodynamic changes because none were observed in this experimental model. The isoprene increase seems to be of metabolic origin and appears to be connected in some way with the extracorporeal circuit. These interesting findings provide a further impulse to study the biosynthetic pathways involved and to investigate the medical and biological significance of isoprene in humans.

[Historical Archives of Italian Nephrology. The form, evocative of function. A short historical review about the discovery of drugs from the most remote times to new trends in pharmacological sciences]. / Archivi storici della Nefrologia Italiana. Nella forma le sembianze della funzione. Una breve rivisitazione storica sulla scopertadei farmaci, dai tempi antichi sino alle più recenti tendenze nelle scienze farmacologiche.

The image, the imaginary and the imagined are more than ever the guide in pharmacological research, and predominate in the expectations of discovering, designing and producing a potential drug. The concept of ""form"" is now corroborated and implemented by the most recent and astounding acquisitions on the existing relationship in biology between form, structure and function. This article is a brief historical reconstruction of how the ""form"" has represented, from the most remote times, a fundamental guiding criterion in the choice of potential pharmacological remedies, and how in times of biotechnology and informatics the design and development of new drugs is based on the assumption that the form-function requisite is among the most promising trends in pharmacological sciences and drug discovery, in the nephrology field too.

[Historical Archives of Italian Nephrology. The gout as a paradigmatic example of the ancient humoral theory of diseases]. / Archivi storici della Nefrologia Italiana. La gotta come paradigma e superamento dell'antica teoria umorale delle malattie.

Gout is one of the oldest known diseases. The term derives from the Latin "gutta", which means "a drop" This word expresses and describes, as no other term can, a method of interpreting the pathologies that have been with us for more than 2000 yrs. The theory of humoral disturbance goes back to the time of Hippocrates. This paper is a historical review of gout, with particular attention given to the interpretation of the origins of clinical, articular and renal involvement allowing us paradigmatically to sum up all the stages in the evolution of the etiopathogenetic and nosographic concepts of medicine through the ages.

Omeprazole induces apoptosis in jurkat cells.

We report for the first time a potent apoptotic effect of omeprazole (OM). Apoptosis was induced in Jurkat cells in a time and concentration-dependent mode. Caspase 3 and PARP were rapidly cleaved in response to OM, but apoptosis was only partially inhibited by the caspase 3 inhibitor DEVD-CHO. OM also induced an early lysosomal destabilization which increased progressively and was correlated with a parallel increase in apoptotic cells. The cysteine protease inhibitor E64d gave strong protection against apoptosis thus proving the involvement of lysosomal enzymes in OM-induced apoptosis whereas, it did not impede the caspase 3 cleavage. Instead ZVAD-fmk, a general caspase inhibitor, also able to inhibit cathepsin activity, protected cells completely from OM-induced apoptosis. It therefore seems that both caspases and cysteine cathepsins are involved in the execution stage of OM-induced apoptosis.

[When the history of nephrology changed that of medicine]. / Archivi storici della nefrologia italiana: quando la storia della nefrologia cambiò quella della medicina.

Medicine owes much to nephrology. Indeed many of the practical and doctrinal acquisitions, through nephrology have derived their first intuitions, explanations and applications which have become epochal conquests of scientific progress. This article is a historical reconstruction of six of the milestones which have marked the medical and scientific human progress: Galeno, the ligature of the ureters and the birth of experimental medicine; uroscopy and the introduction of laboratory exams; the synthesis of urea in the laboratory and the beginnings of biothecnology; the kidney and the introduction of systematic parenteral antibiotic therapy; the kidney and the first artificial organs; the kidney and the start of the transplantation era.

Expression modes of urinary N-acetyl-beta-D-glucosaminidase in patients with chronic renal insufficiency.

BACKGROUND: Urinary N-acetyl-beta-D-glucosaminidase (NAG) activity has emerged as potentially useful early marker of renal tubular injury. This activity is usually evaluated in random urine samples and is related to urinary creatinine concentration. Reports about the lack of correlation between NAG activity of 24-h urines and activity of random urine samples in some clinical and experimental situations led us to study the correlation existing between different procedures for expressing urinary NAG in patients with chronic renal insufficiency. METHODS: Thirty samples of 24-h urine and 30 random urine samples from chronic renal insufficiency patients were collected. The activity of urinary NAG was examined fluorimetrically. RESULTS: The following correlations were observed: (1) r = 0.431 (P = 0.017) for activity in random urine samples and total activity in 24-h urines); (2) r = 0.281 (P = 0.005) for activity in random samples and activity, expressed as U/l, in 24-h urines. CONCLUSIONS: The data show that collection of urine excreted over the whole day and evaluation of total daily excretion of NAG seems the method of choice, at least for patients with chronic renal insufficiency.

N-acetyl-beta-D-glucosaminidase activity in urine of dental personnel.

BACKGROUND: Dental personnel is exposed to several potential nephrotoxic agents. Urinary N-acetyl-beta-d-glucosaminidase (U-NAG) activity has emerged as a sensitive marker of early nephrotoxicity. METHODS: U-NAG was evaluated, by fluorimetric assay, in urine from 30 healthy subjects and 30 dental personnels. RESULTS: The median value of U-NAG activity (133.5 U/mmol urinary creatinine (U-Cr) in urines of dental personnel was not statistically different (P>0.05) from activity (100.7 U/mmol U-Cr) of control urines. CONCLUSIONS: The results suggest that, for dental personnel, exposure to potential nephrotoxic agents is not usually high enough to increase U-NAG activity.

Changes in plasma level of human leukocyte elastase during leukocytosis from physical effort.

Physical exercise is known to induce immunological changes, mainly leukocytosis and neutrophil activation. However, it is not known to what extent the leukocytosis, observed after exertion, is associated with an increase in plasma neutrophil elastase, an early marker of inflammatory response and neutrophil degranulation. In the present study changes in circulating leukocyte and neutrophil counts and human neutrophil elastase plasma levels were evaluated in volley-ball players before and after 2 h and 12 h prolonged training, during a competition season. For comparison, the same parameters were evaluated in untrained subjects before and after a jogging session. Basal white blood cell WBC, polymorpho nuclear PMN, and human polymorpho nuclear-elastase PMN-ELA values were within the normal healthy reference range and no significant differences were found between the two groups studied. Venous blood samples of nine volley-ball players showed a statistically significant increase in blood WBCs after 2 h exercise. This effect was paralleled by a statistically significant increase in PMN-ELA concentration compared to the values observed in the same individuals at rest. The exercise did not significantly change the basal correlation parameters between PMN level and PMN-ELA concentration. More pronounced WBC, PMN, and PMN-ELA increases were observed in the seven inactive subjects after 2 h jogging. There was no linear correlation between increased PMN counts and increased PMN-ELA concentrations in untrained subjects after exercise. The results show that not only the leukocyte count but also PMN-ELA plasma levels can be higher after physical effort. This has a practical significance as regards differential diagnosis demonstrating that determination of these two laboratory parameters can give abnormally high values even in the absence of an existing inflammatory process. Besides, lack of correlation between PMN count and PMN-ELA plasma levels in the untrained group suggest a state in which activation of the neutrophils is not connected with their number in peripheral blood.

[Historical Archives of Italian Nephrology: Scientific ideas and projects carried out by the history of medicine and nephrology]. / Archivi storici della Nefrologia Italiana: La storia della medicina e della nefrologia come pilastro metodologico e veicolo di idee e progetti.

Some recent historical celebrations of modern Italian nephrology offer the opportunity to write about the meaning of the history of medicine and nephrology. First of all, the question "what do we learn from history" is wrongly phrased. It is from trying to learn about history, from the effort required to achieve a historical and epistemological perspective, that we may learn how people as individuals or as a group solved the problems of meeting their common human needs. Medicine is itself an eminently historical endeavour. There is history in medicine as well as history of medicine. According to Paracelsus, the history of medicine is medical science and medical science is essential history in the widest sense of the word. The word "history" embraces the concepts of human nature, the world in which human nature is revealed and the thoughts guiding it through life. If the history of medicine and nephrology is observed in all aspects of their evolution, we can see how it had a beneficial role on the work of physicians by reminding them that, prior to the light of achievement, the discovery of all medical principles is preceded by errors and doubts. We report on nephrological debates, controversies and achievements and we call attention to the need to focus on the present through the involvement of medical historians in the analysis of contemporary health policy issues and clinical methodology.

Plasma endothelin-1 and big endothelin-1 levels in superior and inferior vena cava during protracted antiorthostatic hypokinetic/hypodynamia in rats.

The plasma levels of endothelin-1 and big endothelin-1 were evaluated in blood of rats in the superior and inferior vena cava, in normal posture (synchronous controls), and after 12 days head-down suspension and 1 day recovery in normal posture. In synchronous controls, the mean plasma concentration of endothelin-1 in inferior vena cava or superior vena cava was almost the same (5.89+/-0.63 pmol/l and 5.67+/-0.64 pmol/l, respectively), whereas the mean plasma concentration of big endothelin-1 was higher (p<0.05) in superior vena cava compared to inferior vena cava (5.49+/-0.75 pmol/l and 1.39+/-0.15 pmol/l, respectively). In samples from superior vena cava of head-down suspended rats big endothelin-1 levels were significantly lower (p<0.05) up to day 9 of suspension, compared to non-suspended synchronous controls, whereas endothelin-1 values were higher (p<0.05). Big endothelin-1 concentration was higher (p<0.05) in inferior vena cava compared to non-suspended synchronous controls. The behaviour of endothelin-1 was more complex, endothelin-1 levels were lower (p<0.05) on day 1 of head-down suspension and higher (p<0.05) in samples taken on days 9 and 12. After 1 day recovery endothelin-1 and big endothelin-1 concentrations returned to normal in both superior vena cava and inferior vena cava. These data indicate that the endothelial system involvement for the two venous beds is different and suggest that local rather than systemic evaluation could better explain endothelial involvement and the contribution of different anatomic sites to the biosynthesis, conversion and clearance of the various involved molecules.

Onset, time course, and persistence of increased haemodialysis-induced breath isoprene emission.

Recent findings of increased isoprene emission in the exhaled breath of patients undergoing haemodialysis and experimental evidence of the potential toxic and cancerogenic effects of isoprene hydrocarbon led us to assess how long haemodialysis patients are exposed to how much isoprene after a single haemodialysis session. Patients with end-stage renal failure on regular 4-hour (from 08.00 to 12.00 h) maintenance haemodialysis three times weekly were monitored. The breath isoprene content was analyzed by gas chromatography. Intrapatient evaluations were performed by collecting samples before, during, and immediately after the haemodialysis session, during the following hours, and on the following nondialysis day. The breath isoprene content increased in all patients. Isoprene overproduction showing a biphasic pattern was first detected soon after the dialysis session ended. These data show that haemodialyzed patients seem to be consistently exposed to high endogenous isoprene concentrations. The mechanisms and implications of this endogenous isoprene overproduction need to be elucidated with regard to the mevalonic pathway and in the physiopathological setting of the uraemia-dialysis syndrome.

Plasma sulfate concentration and hyperhomocysteinemia in hemodialysis patients.

BACKGROUND: Severe hyperhomocysteinemia is common in hemodialysis patients, who also present a dramatic increase in plasma concentrations of sulfate, one of the main products of methionine and cysteine catabolism. The aim of this study was to verify the relationship between high plasma sulfate levels and cysteine or homocysteine concentrations in hemodialysis patients. METHODS: Plasma sulfate, cysteine and homocysteine concentrations and some renal efficiency parameters were determined in 18 patients with end-stage renal failure, all undergoing 4h hemodialysis three times a week. The pattern of post-dialysis rises on plasma concentrations of sulfate, cysteine and homocysteine was established. RESULTS: Plasma sulfate, cysteine and homocysteine levels were significantly higher in patients than in normal controls. Plasma sulfate concentrations positively correlated with cysteinemia (p = 0.031; r = 0.482) which, in turn correlated with homocysteinemia (p = 0.042; r = 0.460). Sulfate levels also correlated with blood creatinine (p = 0.004; r = 0.630), nitrogen (p = 0.000; r = 0.899), protein (p = 0.014; r = 0.555), and albumin (p = 0.003; r = 0.642). Post-dialysis rises in sulfate and cysteine were detected some hours before homocysteine. CONCLUSION: The results suggest that high sulfate levels, due mainly to impaired renal function, are involved in the altered metabolism of homocysteine in hemodialysis patients.

Beta-N-acetylhexosaminidase activity and isoenzyme profile in the kidney and urine of trained rats.

Lysosomes play an important role in the immune system functioning and are involved in different aspects of inflammatory reaction, repair processes and tissue damage at various levels. Among various effects, it is known that physical exercise influences the release of different lysosomal components. The aim of this study was to evaluate enzyme activity and isoenzymatic profile of beta-N-acetylhexosaminidase both in kidney and urine of normal and trained rats. Enzyme activity was measured by fluorimetric assay while beta-N-acetylhexosaminidase isoenzymes were separated using DEAE-cellulose chromatography. Hexosaminidase specific activity was significantly increased in urine of trained rats whereas there was no increase in the kidneys of trained rats. Indeed, no significant differences were observed in the isoenzyme profile of kidney and urine extracts from normal and trained rats. Our findings suggest the exercise-induced release of lysosomal enzymes is a functional effect and not due to disruption of lysosomal membranes.

Neutrophil peripheral count and human leukocyte elastase during chronic lithium carbonate therapy.

Plasma levels of human polymorphonuclear elastase (PMN-E) are considered a marker of granulocyte activation and can potentially complement the peripheral neutrophil count in laboratory and pathophysiological settings. Neutrophilic leukocytosis is a well known effect of lithium therapy, but there is no information about the concomitant behaviour of PMN-E in these patients. The aim of this study was to evaluate both polymorphonuclear leukocyte count and plasma PMN-E levels in depression patients undergoing chronic lithium therapy. Absolute and differential leukocyte count in venous peripheral blood was determined by an automated method, and PMN-E evaluated by enzyme immunoassay. 39 patients (11 males, 28 females; mean age 43. +/- 6.02) with depression disorders were studied, during lithium carbonate therapy. Neutrophilia (neutrophil count > 7.500x10(9) cells per liter) was found in 7 (18%) patients and an increase in plasma PMN-E levels (PMN-E > 56 microg per liter ) in 6 (15%). No correlations were found between neutrophil count, plasma concentration of PMN-E, plasma level of lithium and duration of therapy. The results show that in these patients, not only the PMN count but also elastase levels can exceed the normal range. The absence of correlation between these two parameters suggests that the state of PMN activation is not linked to their number in peripheral blood.

In vitro effects of meropenem and imipenem/cilastatin on some functions of human natural effector cells.

Meropenem, a new carbapenem antibiotic, was assessed to evaluate its effects on some functional parameters of human polymorphonuclear (PMN) and natural killer (NK) cells in comparison with imipenem/cilastatin. Both drugs significantly inhibited PMN phagocytosis and chemotaxis at concentrations of 2,000 and 4,000 microg/ml. They affected PMN microbicidal activity, evaluated against Candida albicans, only at 4,000 microg/ml. A study of the effects of both drugs on peripheral NK populations and the human NK line (NK-92) showed that even at 4,000 microg/ml there was no effect on antitumor activity. These data indicate that meropenem can reduce some PMN antimicrobial functions only at very high concentrations like imipenem/cilastatin, whereas no concentration influenced NK activity.

Volatile alkanes and increased concentrations of isoprene in exhaled air during hemodialysis.

In this study we examined breath volatile hydrocarbon concentrations in exhaled air of hemodialysis patients. We assessed both C(2)-C(5) alkanes - among them ethane and pentane the production of which in man is essentially due to the action free radicals exert on polyunsaturated fatty acids - and isoprene, an unsaturated hydrocarbon the biosynthesis and biological effects of which are the subject of controversy and mounting interest. Twenty patients were studied. Evaluation was performed intrapatient in the breath of patients with chronic renal failure, before and after dialysis (20 patients) and, in the same cases, during hemodialytic treatment (10 patients). Breath concentrations of these volatile hydrocarbons, determined before dialysis, were not different from those of normal subjects. Dialysis did not modify the levels of the C(2)-C(5) saturated hydrocarbons ethane, propane, butane and pentane. Instead, there was a marked increase in isoprene in all patients (basal values rose by a mean of 270%). Since isoprene was not present in the fluids or filters used for dialysis and there were only traces in the ambient air, the isoprene must have been produced endogenously during hemodialysis. As no situation has previously been reported to increase endogenous production of isoprene in humans, patients in hemodialysis offer a unique opportunity to investigate in depth the medical, biological and toxicological aspects of isoprene.