Mycobacteriosis caused by Mycobacterium marinum in reared mullets: first evidence from Sardinia (Italy).

Mycobacterium marinum is a slow-growing non-tuberculous mycobacterium, and it is considered the most common aetiologic agent of mycobacteriosis in wild and cultured fish. The diagnosis is principally made by histology when positive Ziehl-Neelsen stain granulomas are detected. The aim of this study was to investigate the occurrence of mycobacteriosis in extensively cultured Mugilidae of two lagoons (Cabras and San Teodoro) from Sardinia by the use of histology, microbiology, PCR and DNA sequencing. Nine of 106 mullets examined were affected by mycobacteriosis, and the spleen was the most affected organ. The histology detected higher rate (100%) of infection in spleen than the culture and PCR (75% and 62.5%, respectively). The sequencing of hsp65 gene identified M. marinum as the primary cause of mycobacteriosis in the mullets examined. Mullets affected by mycobacteriosis were mainly fished in the San Teodoro lagoon characterized by critical environmental conditions. Histology remains the most common method in detecting fish affected by mycobacteriosis, and PCR-based methods are essential for species identification. Our finding are worthy of attention because mycobacteriosis caused by M. marinum in reared mullets was evidenced for the first time in Sardinia, suggesting that this disease may be underestimated also in other cultured fish species.

Oxidative stress related to chlorpyrifos exposure in rainbow trout: Acute and medium term effects on genetic biomarkers.

Organophosphates (OPs) are derivatives of phosphoric acid widely used in agriculture as pesticides. Chlorpyrifos (CPF) is an OP that is extremely toxic to aquatic organisms. Rainbow trout (Oncorhynchus mykiss) is considered as a sentinel model species for ecotoxicology assessment in freshwater ecosystems. An exposure study was carried out on rainbow trout to investigate genetic responses to CPF-induced oxidative stress by Real-Time PCR, and to determine the accumulation dynamics of CPF and toxic metabolite chlorpyrifos-oxon (CPF-ox) in edible parts, by HPLC-MS/MS. Among the genes considered to be related to oxidative stress, a significant increase in HSP70 mRNA levels was observed in liver samples up to 14 days after CPF exposure (0.05 mg/L). CPF concentrations in muscle samples reach mean values of 285.25 ng/g within 96 hours of exposure, while CPF-ox concentrations were always under the limit of quantification (LOQ) of the applied method. Our findings lead us to consider HSP70 as a suitable genetic marker in rainbow trout for acute and medium-term monitoring of CPF exposure, complementary to analytical determinations.

Granulomatous lesions in a wild mullet population from the eastern Ligurian Sea (Italy): mycobacteriosis vs. pseudotuberculosis.

Mycobacterium spp. and Photobacterium damselae subsp. piscicida are recognized as the most frequent causative agents of granulomatous lesions in fish. Although frequent episodes of mycobacterial infections have been reported in wild fish worldwide, only sporadic cases have been documented to date in Italy. To investigate for the presence of lesions referable to mycobacteriosis and to identify the mycobacterial species involved, a total of 159 wild mullets were fished from the eastern coast of the Ligurian Sea, killed and necropsied. Liver and spleen samples were collected from all fish for histopathological and microbiological analyses. Molecular investigations for identification of Photobacterium damselae subsp. piscicida were performed. Gross examination revealed granulomatous lesions in one animal; microscopically, 42.14% of fish displayed granulomas with various histological features, 19.50% resulted positive at Ziehl-Neelsen staining, and were confirmed as mycobacterial lesions by culture. The identified colonies were characterized as M. fortuitum, M. abscessus, M. flavescens, M. chelonae, M. septicum and M. nonchromogenicum. In all, 35% of animals resulted positive for Photobacterium damselae subsp. piscicida. These data suggest widespread mycobacterial infection also by Photobacterium damselae subsp. piscicida infections in wild fish. Moreover, the pathogenicity of some mycobacterial species, previously considered as saprophytic, was demonstrated.

[Folate metabolism dysfunction]. / Alterazioni del metabolismo dell'aciso folico.

This review examines the history of folate, its metabolism and its relationship to drugs and diseases. The scientific interest in folate has been increasing in recent years because of new findings related to its important role in many diseases like macrocytic anemia, congenital malformations, vascular thrombosis, atherosclerotic disease and cancer. The fascinating puzzle of folate is analyzed and the most recent news about folate treatment in patients with chronic renal failure is reported.

Association of the alpha-adducin locus with essential hypertension.

Previous studies on genetic rat hypertension have shown that polymorphism within the alpha-adducin gene may regulate blood pressure. Adducin is a cytoskeletal protein that may be involved in cellular signal transduction and interacts with other membrane-skeleton proteins that affect ion transport across the cell membrane. There is a high homology between rat and human adducin and pathophysiological similarities between the Milan hypertensive rat strain and a subgroup of patients with essential hypertension. Thus, we designed a case-control study to test the possible association between the alpha-adducin locus and hypertension. One hundred ninety primary hypertensive patients were compared with 126 control subjects. All subjects were white and unrelated. Four multiallelic markers surrounding the alpha-adducin locus located in 4p16.3 were selected: D4S125 and D4S95 mapping at 680 and 20 kb centromeric, and D4S43 and D4S228/E24 mapping at 660 and 2500 kb telomeric. Alleles for each marker were pooled into groups. Comparisons between control subjects and hypertensive patients were carried out by testing the allele-disease association relative to the marker genotype. The maximal association occurred for D4S95 (chi 2(1) 13.33), which maps closest to alpha-adducin. These data suggest that a polymorphism within the alpha-adducin gene may affect blood pressure in humans.

Na+,K+,Cl- cotransport is a marker of distal tubular function in essential hypertension.

OBJECTIVE: To analyze the natriuretic and diuretic response to frusemide in 33 male essential hypertensive patients as a function of basal renal sodium handling and erythrocyte transport system. METHODS: The natriuretic and diuretic response to an oral dose of frusemide (25 mg) was assessed with a simplified method. Urinary sodium and water excretion were measured in the basal state and every 30 min after the frusemide dose for 240 min. Basal 24h urinary sodium and water excretion, Na+,K+,Cl- cotransport and Li+-Na+ countertransport were measured 24 h before the test. RESULTS: There was a highly significant correlation between the natriuretic and diuretic response to frusemide and Na+,K+,Cl- cotransport and Li+-Na+ countertransport. After a multiple regression analysis the natriuretic and diuretic response to frusemide was not correlated with indices of proximal tubular function (Li+-Na+ countertransport, fractional uric acid excretion and the ratio of fractional sodium excretion to fractional uric acid excretion). CONCLUSION: These results support the hypothesis that erythrocyte Na+,K+,Cl- cotransport is a marker of distal tubular function.

Cigarette smoking and kidney involvement.

Cigarette smoking has adverse effects on health causing ischemic heart disease, stroke, chronic obstructive lung disease and cancers of the respiratory and upper digestive tract, pancreas, kidney and urinary tract. Smoking causes an acute increase in mean arterial pressure and heart rate mediated by catecholamines and beta-adrenergic mechanisms. Chronic cigarette smoking reduces renal plasma flow, probably increasing synthesis of the vasoconstrictor endothelin and reducing generation of the vasodilatory endothelial nitric oxide. There is clinical evidence that cigarette smoking has important adverse effects on renal outcome in primary hypertension, diabetic nephropathy, primary glomerular diseases, systemic diseases involving the kidney and in patients on chronic hemodialysis, or after renal transplantation.

Autosomal recessive and dominant polycystic kidney diseases.

It is possible to identify renal cysts in several subjects by ultrasonography imaging techniques. Among the inherited polycystic kidney diseases we include autosomal recessive polycystic kidney disease (ARPKD) and autosomal dominant polycystic diseases such as von Hippel-Lindau disease, tuberous sclerosis complex (TSC1 and TSC2), and autosomal dominant polycystic kidney disease (ADPKD). ARPKD is a rare disease, related to PKHD1 gene, located on chromosome 6p21, that encodes a protein named polyductin/fibrocystin. Pathoanatomical features are bilateral kidney involvement with multiple microcysts, and invariably liver involvement with portal and interlobular fibrosis. A single genetic defect leads to different degrees of renal and hepatic involvement with very different phenotypes and different clinical outcome, in the same family too. ARPKD clinically may show 4 different forms: perinatal, neonatal, infantile, and juvenile. ADPKD is much more frequent (1: 400-1000 live births), and can arise from mutations in 2 different genes, named PKD1 located on chromosome 16p13.3, and PKD2 located on chromosome 4q21-23. The proteins encoded by the PKD1 and PKD2 genes are named polycystins which play crucial roles in several biologic processes. To explain the focal lesions that affected different organs and tissues the "double hit" theory has been proposed (germinal mutation plus somatic mutation on PKD1 or PKD2). Recently, biologic evidence documented the crucial role of the renal primary cilia on the formation of polycystins to induce cystogenesis. ADPKD may be clinically characterized by abdominal pain, hypertension, episodes of gross hematuria, headache, renal stones, aortic and cerebral aneurysms, mitral valve prolapse, and polycystic liver disease. ADPKD is slowly progressive disease responsible for up 10% of end stage renal failure (ESRF) in every country of the world. Male sex, PKD1 gene, episodes of gross hematuria, and the precocity and severity of hypertension play an important role in the progression of renal disease to ESRF.

[Homeopathy: principles, status of research, research design; comment]. / Homöopathie: Grundlagen, Stand der Forschung, Forschungsstrategien.

This paper gives an overview of homoeopathy: 1. scientific foundations-2. problems and importance of research in homoeopathy-3. of research findings in basic and clinical research-4. future strategies of evaluation. Homeopathy is a medical discipline in its own right which is quite different from orthodox medicine in its basic tenets, its research paradigms and its practical approach to therapy, even though both methods are empirically founded and share the aim of healing the sick. When homoeopathy is pressed into a framework of research paradigms alien to its own approach, this is bound to engender difficulties because of the partial incompatibility. In spite of that, some studies with rigorous design have shown that homoeopathic remedies are effective. The important research findings are discussed and future strategies for evaluation are proposed.

Evolution of renal pathology in Fabry disease.

UNLABELLED: Fabry disease is a rare lysosomal storage disorder which results from deficient activity of the enzyme alpha-galactosidase A. The resultant deposition and progressive accumulation of glycosphingolipids in all types of body tissue leads to severe clinical manifestations involving the heart, CNS and kidney. Renal manifestations are observed relatively early in the course of the disease, and progression to end-stage renal failure is common in hemizygous males in the third to fifth decades of life. Renal biopsy specimens reveal evidence of diffuse intracytoplasmic glycosphingolipid accumulation, mainly affecting podocytes and epithelial cells of distal tubules, which are strikingly enlarged and vacuolated. On electron microscopy the deposits appear as typical osmiophilic inclusion bodies in the cytoplasm of all kinds of renal cells, and show a characteristic 'onion skin' or 'zebra' appearance. These pathological features are also evident in heterozygous females. Deposits occur before the development of renal impairment. As patients age, the disease progresses in cells throughout the kidney, and is associated with increasing glycosphingolipid accumulation. CONCLUSION: The age-related evolution of renal pathology in Fabry disease is closely correlated with progressive intracellular deposition of glycosphingolipid and ultimately leads to end-stage renal failure.

[A single centre study about the effects of HFR on anemia]. / Studio monocentrico relativo agli effetti dell'emodiafiltrazione con reinfusione endogena (HFR) sull'anemia.

PURPOSE: Erythropoietin (EPO) deficiency, erythropoiesis inhibition and reduction in red blood cell survival are the main causes of anemia in endstage renal disease (ESRD). Hemodiafiltration (HDF) with on-line endogenous reinfusion eliminates backfiltration and uses an ultrapure dialysate and reinfusate. This technique should improve anemia correction by increasing uremic toxin removal and reducing inflammatory cytokine production. In this study, we evaluated the effects of HDF with on-line endogenous reinfusion on anemia correction. METHODS: This was a single-center, prospective and non-randomized study. We selected 12 patients on EPO therapy with steady haemoglobin (Hb) values; eight patients were treated with bicarbonate dialysis and four patients with on-line HDF. We switched them to HDF with on-line endogenous reinfusion for 6 months, changing the EPO dose when Hb levels were not within the 11-12 g/dL range. Biochemical data were measured every month. Results are expressed as means +/- m.s.e. Data were analyzed using the Student's t-test and analysis of variance for repeated measurements. A value p<0.05 was considered statistically significant. RESULTS: Patients maintained the same Hb, ferritin and dialytic efficiency throughout the study. The EPO supplementation was significantly higher in patients treated with bicarbonate dialysis (108 +/- 8 UI/kg/week as compared with patients treated with on-line HDF (36 +/- 5 UI/kg/week) during the 6 months before treatment by HDF with on-line endogenous reinfusion. In the last 6 months, we detected a reduction in EPO consumption, but not statistically significant, in the patients switched from bicarbonate dialysis to HDF with on-line endogenous reinfusion (83 +/- 6 UI/kg/week). CONCLUSIONS: The change from bicarbonate dialysis to HDF with on-line endogenous reinfusion caused a reduction in EPO supplementation and, consequently, a reduction in the cost of anemia therapy. It is necessary to increase the size of the study group and to prolong the observation period to possibly obtain statistical significances.

Cardio-renal-anemia syndrome: a link between erythropoietin, dimethylarginine and homocysteine.

Cardio-renal-anemia syndrome is a combination of heart failure, kidney failure, and anemia. Many advanced chronic kidney disease patients have both anemia and chronic heart failure. They have often hyperhomocysteinemia, high dimethylarginine values and low erythropoietin levels. Nephrologists treat advanced chronic kidney disease patients with erythropoiesis stimulating agents to improve anemia, renal and heart disease. Erythropoiesis stimulating agents, though considered essential to improve anemia in chronic kidney disease patients, have shown no significant protective effect on cardiovascular disease when used in large clinical trials targeting normal hemoglobin levels. It is possible that the high amounts of these drugs, given to reach normal hemoglobin values, may have counterbalanced the positive effect on endothelium obtained with low doses. Many studies have shown that erythropoietin improves endothelial function in animals with high dimethylarginine levels, lowering asymmetric dimethylarginine and increasing nitric oxide synthesis. Advanced chronic kidney disease patients have also high homocysteine levels which further reduce endothelial function by increasing asymmetric dimethylarginine. Homocysteine-lowering vitamin B treatment has been associated to a significant reduction of cardiovascular disease in advanced chronic kidney disease patients. Low doses of epoetin and B vitamins may improve cardiovascular morbidity by reducing asymmetric dimethylarginine and by increasing nitric oxide synthase activity. This review analyses the interaction between erythropoietin, dimethylarginine and homocysteine, and their role in cardio-renal-anemia syndrome.

The in vitro metabolism of mevalonate by sterol and non-sterol pathways.

The metabolism of mevalonic acid by both sterol and non-sterol pathways has been evaluated in nine tissues of the rat. An in vitro estimation of the non-sterol, or "shunt", pathway of mevalonate metabolism was made possible by determining the conversion of [2-14C]mevalonate or [5-14C]mevalonate to 14CO2 in tissue slices. In confirmation of our previous results, the kidney was found to play a major role in the metabolism of mevalonate to sterols and sterol precursors. The shunt pathway accounted for a significant percentage of the mevalonate metabolized in kidney, ileum, spleen, lung and testes, but was of minor importance or undetectable in liver, brain, skin, and adipose tissue. Kidney, however, proved to be by far the most active tissue site of mevalonate metabolism by the shunt mechanism in that, on an average, renal tissue metabolized (R)-[14C]mevalonate over the non-sterol pathway at a rate that was 21 times that of any other tissue examined. These results indicate that the kidneys are of major importance in the metabolism of mevalonate by each of the known pathways of metabolism of this sterol precursor.

Alpha-adducin polymorphisms and renal sodium handling in essential hypertensive patients.

The relationship between blood pressure and sodium (Na) excretion is less steep in hypertension caused by increased renal tubular reabsorption. We recently demonstrated that one mutation in rat alpha-adducin gene: (1) is responsible for approximately 50% of the hypertension of MHS rats, and (2) stimulates tubular Na-K pump activity when transfected in renal epithelial cell, suggesting that its pressor effect may occur because an increased tubular reabsorption. Linkage and association studies demonstrated that the alpha-adducin locus is relevant for human hypertension. A point mutation (G460W) was found in human alpha-adducin gene, the 460W variant (G/W) is more frequent in hypertensives than in normotensives. The aim of this study was to test whether acute changes in body Na may differently affect blood pressure in humans as a function of alpha-adducin genotype. The pressure-natriuresis relationship was analyzed in 108 hypertensive using two different acute maneuvers: Na removal (furosemide 25 mg p.o.) and, two days later, Na load (310 mmoles i.v. in 2 hr). We found that 80 patients were wild-type homozygous (G/G), 26 were G/W heterozygous, and 2 were W/W homozygous with similar blood pressure, age body mass index, gender, plasma and urinary sodium and potassium. In basal condition G/W-W/W patients showed a lower plasma renin activity and fractional excretion of Na. In either case the pressure-natriuresis relationship was less sleep in G/W-W/W than in G/G patients, obviously negative for Na depletion with furosemide (-0.011 +/- 0.004 vs. -0.002 +/- 0.002 mm Hg/mumol/min, P < 0.03), and positive for Na load (0.086 +/- 0.02 vs. 0.027 +/- 0.007 mm Hg/mumol/min, P < 0.001). The finding of reduced slope after Na depletion or Na load supports the hypothesis that, as MHS rats, humans bearing one W alpha-adducin variant display an increased of renal tubular sodium reabsorption.

Polymorphisms of alpha-adducin and salt sensitivity in patients with essential hypertension.

BACKGROUND: Abnormalities in renal sodium transport may be involved in hypertension. Adducin, an alpha/beta heterodimeric protein found in the renal tubule is thought to regulate ion transport through changes in the actin cytoskeleton. We investigated whether an alpha-adducin polymorphism (Gly 460 Trp) is involved in essential hypertension in two separate populations. METHODS: Linkage analysis of three DNA markers at different distances from the alpha-adducin locus (20-2500 kb) was done in 137 hypertensive sibling-pairs. 477 hypertensive and 322 normotensive individuals were genotyped for the alpha-adducin polymorphism. The blood-pressure response to acute and chronic changes in sodium balance was studied in hypertensive individuals with and without the 460 Trp alpha-adducin allele. FINDINGS: Significant linkage was found for all three markers in the sibling-pair study. The extra shared alleles (9.1%, 6.5%, and 4.7%) and the significance level for linkage (p = 0.0006, p = 0.0119, and p = 0.0211) both decreased with increasing distance from the alpha-adducin locus. There was a significant association between the 460 Trp mutation and hypertension (p = 0.0003). In the salt-sensitivity test, to assess the acute blood-pressure response to changes in body sodium in 86 hypertensive patients, the decrease in mean arterial pressure was greater in 65 patients who were heterozygous for the mutant allele (Gly/Trp) than in 21 wild-type homozygotes (Gly/Gly) (mean decrease 15.9 [SE 2.0] vs 7.4 [1.3] mm Hg; p = 0.001). Similarly, 21 heterozygous hypertensive patients showed a greater fall in mean arterial pressure in response to 2 months' treatment with hydrochlorothiazide than did 37 wild-type homozygous hypertensive patients (mean decrease 14.7 [2.2] vs 6.8 [1.4] mm Hg; p = 0.002). INTERPRETATION: Our findings of significant linkage of the alpha-adducin locus to essential hypertension and greater sensitivity to changes in sodium balance among patients with the mutant allele suggest that alpha-adducin is associated with a salt-sensitive form of essential hypertension. We suggest the alpha-adducin polymorphism may identify hypertensive patients who will benefit from diuretic treatment or manoeuvres to reduce total body sodium.