Hyperhomocysteinemia in Greek patients with inflammatory bowel disease.

In recent years hyperhomocysteinemia has been established as a new risk factor for arterial and venous thrombosis. Since patients with inflammatory bowel disease (IBD) frequently suffer from thromboembolic events, we studied the prevalence and clinical significance of hyperhomocysteinemia in Greek patients with ulcerative colitis (UC) and Crohn's disease (CD). In 108 consecutive fasting IBD patients (53 UC and 55 CD) and 74 healthy controls (HC), a standard record of various clinical thrombotic risk factors was completed by interview, and fasting serum concentrations of total homocysteine (tHcy), folate, cobalamin, creatinine, cholesterol, HDL, LDL, and triglycerides were measured.

PLC-gamma1 signaling pathway and villin activation are involved in actin cytoskeleton reorganization induced by Na+/Pi cotransport up-regulation.

Background: The brief incubation of opossum kidney (OK) cells with low P(i) results in Na+/P(i) cotransport up-regulation and in substantial, but transient, cytoskeletal reorganization. In this study, we examined signaling events involved in the depolymerization of microfilaments.

Results: Confocal laser scanning microscopy, immunoblot and immunoprecipitation experiments revealed villin co-localization with mainly actin short filaments and monomers, indicating that under the conditions used, villin acted as an actin-severing protein.

TNF-alpha induces actin cytoskeleton reorganization in glomerular epithelial cells involving tyrosine phosphorylation of paxillin and focal adhesion kinase.

Glomerular permeability for macromolecules depends partially on proper attachment of the glomerular epithelial cells (GEC) to the glomerular basement membrane (GBM). The latter requires integrity of the actin cytoskeleton, which in turn is regulated by specific actin-associated proteins. Since several glomerulopathies characterized by heavy proteinuria are associated with increased glomerular tumor necrosis factor alpha (TNF-alpha) expression, we studied the interaction of TNF-alpha with the actin cytoskeleton of cultured rat GEC.

Acute onset of dermatomyositis presenting in pregnancy with rhabdomyolysis and fetal loss.

We report a case of acute onset of dermatomyositis with rhabdomyolysis and myoglobinuria, which presented in the 14th week of pregnancy and resulted in spontaneous abortion of the fetus. The diagnostic work up for an underlying disease was negative and the histologic examination confirmed the diagnosis of dermatomyositis, which subsequently improved with corticosteroids.

Pneumothorax complicating fatal bronchiolitis obliterans organizing pneumonia.

Bronchiolitis obliterans organizing pneumonia (BOOP) is an uncommon pulmonary disorder, the clinical spectrum of which is variable. We present a fatal case of BOOP, which developed spontaneous pneumothorax, a complication considered rare. Unusual was also the upper lobe distribution of the infiltrates.

Early alterations of actin cytoskeleton in OK cells by opioids.

Recently we identified and characterized opioid binding sites in OK (opossum kidney) cells and observed decreased proliferation of these cells in response to opioids. In the present study we investigated the effects of opioids on the actin cytoskeleton and explored whether their antiproliferative action may relate to alterations in the distribution or the dynamics of actin microfilaments. Exposure of OK cells to the opioids alphaS1 casomorphin and ethylketocyclazocine resulted in a rapid and substantial actin microfilament reorganization.

Identification and characterization of opioid and somatostatin binding sites in the opossum kidney (OK) cell line and their effect on growth.

Opioids and somatostatin analogs have been implicated in the modulation of renal water handling, but whether their action is accomplished through central and/or peripheral mechanisms remains controversial. In different cell systems, on the other hand, opioids and somatostatin inhibit cell proliferation. In the present study, we have used an established cell line, derived from opossum kidney (OK) proximal tubules, in order to characterize opioid and somatostatin receptors and to investigate the action of opioids and somatostatin on tubular epithelial tissue.

Na+/Pi co-transport alters rapidly cytoskeletal protein polymerization dynamics in opossum kidney cells.

We studied with biochemical and immunofluorescent techniques the interactions between the actin microfilament and tubulin microtubule cytoskeleton and Na+/P1 co-transport in opossum kidney cells, a line with proximal tubular characteristics. On brief (5 min) incubation of the cells with a low (0.1 mM) concentration of Pi, a rapid F-actin depolymerization takes place, which fails to occur in cells incubated under similar conditions with 1 mM Pi.

Water channel expression in human ADPKD kidneys.

Cyst enlargement in autosomal dominant polycystic kidney disease (ADPKD) results in part from the transport of solute and fluid into the lumen of the cyst. In proximal tubules and thin descending limbs of normal kidneys, the high transepithelial water permeability of these segments is due to the presence of the water channel protein, aquaporin-CHIP (AQP-CHIP, i.e.

Renal folate absorption and the kidney folate binding protein. I. Urinary clearance studies.

The kidney possesses a high concentration of a folate binding protein (FBP) that resides primarily in the brush-border membrane (BBM) of the proximal tubular cells. To assess the possible involvement of this protein in renal conservation of folate we determined the urinary clearance, in rats, of three forms of folates with sharply different affinities for FBP. After single intravenous injections of 0.

Quantitative effects of osmotic diuresis following angiographic contrast administration.

Osmotic diuresis resulting from the administration of angiographic contrast poses the potential threat of marked volume losses obligated by the renal excretion of non-reabsorbable solute. We prospectively assessed urinary excretion of solute and water following cardiac angiography in 14 euvolemic subjects without preexisting renal disease, by a protocol that allowed each patient to serve as his own control. During the initial 6 h after the beginning of angiography, contrast administration resulted in increased total osmolar excretion from a control rate of 0.

Sites of insulin and glucagon metabolism in the rabbit nephron.

Uptake and degradation of peptide hormones have been demonstrated in proximal convoluted tubules (PCT), but the contribution of other regions of the nephron to renal hormone metabolism is unknown. In the present study we used micromethods to determine for the first time the degradation of radiolabeled insulin and glucagon by each segment of the rabbit nephron and examined some characteristics of this process in proximal convoluted and cortical collecting tubules (CCT). Degradation of insulin (8-10 fmol .

First exchange neutrophilia: an index of peritonitis during chronic intermittent peritoneal dialysis.

During intermittent peritoneal dialysis (IPD) early diagnosis of peritonitis may be difficult, because of paucity in clinical signs and delays in bacteriologic studies. We examined prospectively leucocyte counts and their differential composition in initial ascites and dialysis effluent of patients on IPD and correlated these findings to the presence of subsequently bacteriologically proven clinical peritonitis. Total leucocyte counts from either ascites or first exchange effluent did not differentiate infected from noninfected patients.

Marked proteinuria in hypertensive nephrosclerosis.

Heavy proteinuria in patients with essential hypertension raises the question of underlying primary renal disease. While malignant hypertension may be associated with proteinuria in the nephrotic range, it is generally held that protein excretion in benign nephrosclerosis is almost invariably less than 0.5-1.

Role of the kidney in metabolism of gonadotropins in rats.

The role of the kidney in the metabolic disposal of homologous gonadotropins [renal luteinizing hormone (rLH) and renal follicle-stimulating hormone (rFSH)] was studied in rats. In analogy with other protein hormones, renal mechanisms contributed importantly to their metabolic clearance rates (MCR), which were profoundly and comparably decreased following nephrectomy (by 94 and 78% for rLH and rFSH, respectively). Absolute MCR and renal organ clearance rates of gonadotropins were, however, markedly lower and urinary clearance rates proportionally higher than those of nonglycosylated protein hormones reported previously.

Metabolism of pure human erythropoietin in the rat.

The metabolism of pure human erythropoietin (EPO) labeled with 125I was studied in the rat. Concentrations of the labeled hormone (125I-EPO) in plasma and urine were measured by both trichloroacetic acid precipitation and gel filtration. During steady-state conditions the metabolic clearance rate of 125I-EPO was slow, averaging 256 +/- 7 microliter.

Predominance of renal and absence of hepatic metabolism of pancreatic polypeptide in the dog.

Pancreatic polypeptide (PP) metabolism was studied in the dog. Metabolic clearance rate (MCR) of PP was found to be 9.5 +/- 0.

Insulin binding sites in various segments of the rabbit nephron.

Insulin binds specifically to basolateral renal cortical membranes and modifies tubular electrolyte transport, but the target sites of this hormone in the nephron have not been identified. Using a microassay that permits measurement of hormone binding in discrete tubule segments we have determined the binding sites of 125I-insulin along the rabbit nephron. Assays were performed under conditions that minimize insulin degradation, and specific binding was measured as the difference between 125I-insulin bound in the presence or absence of excess (10(-5) M) unlabeled hormone.

Glucagon degradation by luminal and basolateral rabbit tubular membranes.

Glucagon is avidly degraded by the kidney, but the relative contribution of the luminal and basolateral tubular membranes to this process is unknown. We studied 125I-glucagon degradation by purified luminal (L) and basolateral (BL) tubular membranes prepared from rabbit kidney cortex, which showed enrichment vs. homogenate of marker enzyme activities (Na-K-ATPase for BL and maltase for L) of 10- and 14-fold, respectively.

Differences in the hepatic and renal extraction of insulin and glucagon in the dog: evidence for saturability of insulin metabolism.

The metabolism of exogenously infused porcine insulin and glucagon was assessed concurrently in normal fasted dogs under anaesthesia. Hepatic and renal extraction of glucagon were 25.6 +/- 2.

Insulin binding and degradation by luminal and basolateral tubular membranes from rabbit kidney.

Insulin influences certain metabolic and transport renal functions and is avidly degraded by the kidney, but the relative contribution of the luminal and basolateral tubular membranes to these events remains controversial. We studied (125)I-insulin degradation [TCA and immunoprecipitation (IP) methods] and the specific binding of the hormone by purified luminal (L) and basolateral (BL) tubular membranes. These were prepared from rabbit kidney cortical homogenates by differential and gradient centrifugation and ionic precipitation steps in sequence, which resulted in enrichment vs.

Hepatic and renal metabolism of somatostatin-like immunoreactivity. Simultaneous assessment in the dog.

The hepatic and renal metabolism of somatostatin-like immunoreactivity (SLI) was assessed simultaneously in an in vivo dog model. The hepatic extraction of this peptide was 29.4 +/- 2.