HPLC analysis of tetrahydrobiopterin and its pteridine derivatives using sequential electrochemical and fluorimetric detection: application to tetrahydrobiopterin autoxidation and chemical oxidation.

Tetrahydrobiopterin (BH(4)) is an essential cofactor of endothelial nitric oxide (NO) synthase and when depleted, endothelial dysfunction results with decreased production of NO. BH(4) is also an anti-oxidant being a good "scavenger" of oxidative species. NADPH oxidase, xanthine oxidase, and mitochondrial enzymes producing reactive oxygen species (ROS) can induce elevated oxidant stress and cause BH(4) oxidation and subsequent decrease in NO production and bioavailability.

Isoenzyme A and urinary N-acetyl-β-D-glucosaminidase activity in normal pregnancy.

Objectives: Urinary N-acetyl-β-d-glucosaminidase (NAG) activity has been found to increase during normal uncomplicated pregnancy and such behavior could limit the diagnostic value of this enzyme for detection of subclinical tubular injury. The aim of this study was to evaluate urinary NAG activity and isoenzyme A in normal pregnant women at 30th week of pregnancy and in healthy women, to discriminate between physiological and lesional enzymuria.

Design And Methods: Enzyme activities in first morning fasting urine samples from 20 nonpregnant control and 20 normal pregnant women at 30th gestational week were evaluated by fluorometric methods.

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.

The hepato-pulmonary-cutaneous syndrome: description of a case and suggestion of a unifying hypothesis.

We report a 54-year-old patient with the association of hepatic dysfunction with cyanosis, severe hypoxemia, platypnea-orthodeoxia, diffuse cutaneous spider nevi, telangiectasia, palmar erythema, digital clubbing and findings of marked intrapulmonary vascular dilation and arterovenous shunt. The diagnosis of hepato-pulmonary-cutaneous syndrome, a term we think more appropriate and inclusive than that of hepato-pulmonary syndrome for this clinicopathological picture, is proposed. The putative underlying mechanism for these connected pulmonary and extrapulmonary syndromic features is discussed.

Ruggero Oddi: 120 years after the description of the eponymous sphincter: a story to be remembered.

This article presents a short account of theories, methods, and experimental data formulated and carried out 120 years ago, by Ruggero Oddi, then a 4th-year student in medicine, about the identification of the common bile duct sphincter. A historical picture emerges which leads us to think that Oddi not only discovered the bile duct sphincter, but also described bile duct dilation after cholecystectomy and performed biliary manometry for the first time. The role of serendipity and the almost unknown contribution of Arturo Marcacci, Oddi's "maestro" are also mentioned.

[Occupational injuries and sickness absence: association with job demand, decision latitude, and life style in 2174 workers in the Veneto Region].

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).

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.

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.

Fluorimetric determination of activity and isoenzyme composition of N-acetyl-beta-D-hexosaminidase in seminal plasma of fertile men and infertile patients with secretory azoospermia.

Background: The activity and isoenzyme composition of N-acetyl-beta-D-hexosaminidase (EC.3.2.

[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].

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].

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.

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.

[When the history of nephrology changed that of medicine].

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.

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.

Theories and controversies on urine formation.

The theories of urine formation developed in the wake of progressing scientific knowledge in renal anatomy and physiology. From the philosophical theories which for a long time swung between vitalism and mechanism, the "scientific revolution" gave a great impulse to morpho/functional unit of kidney. Bowman's secretory hypothesis, as an expression of the vitalistic based theory, describes for the first time many features of the nephron and its blood supply.

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.

[Historical Archives of Italian Nephrology: Scientific ideas and projects carried out by the history of medicine and nephrology].

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.

Ippolito Albertini and Michael Albertus: disparate old and innovative theories on dropsy and edema.

The concept of edema and dropsy as a part of heart and renal failure developed in the 17th and 18th centuries with the observations of Albertini, who realized that two clinical entities were derived from the blood rather than the tissues. Albertus, who lived in the same period, was the last physician to interpret fluid accumulation according to the old, scholastic and dogmatic procedures of medicine. The fundamental concepts of Albertus held little in addition to the classification and categories of the physicians of the Middle Ages.