Dimethyl fumarate-induced lymphocyte count drop is related to clinical effectiveness in relapsing-remitting multiple sclerosis.

BACKGROUND AND PURPOSE: Dimethyl fumarate (DMF) causes a mean lymphocyte count drop of approximately 30% in relapsing-remitting multiple sclerosis (RRMS) patients. The relationship between this reduction and DMF effectiveness is controversial. The objective was to investigate if the decrease in absolute lymphocyte count (ALC) from baseline during DMF treatment is associated with clinical and magnetic resonance imaging (MRI) disease activity. A secondary aim was to evaluate ALC variations over time in a real-life cohort of DMF-treated patients. METHODS: Demographic, laboratory, clinical and MRI data were collected in this observational multicentre study, conducted on RRMS patients treated with DMF for at least 6 months. Multivariate Cox models were performed to evaluate the impact of 6-month ALC drop on time to no evidence of disease activity (NEDA-3) status loss. NEDA-3 is defined as absence of clinical relapses, MRI disease activity and confirmed disability progression. RESULTS: In all, 476 patients (312 females, age at DMF start 38.4 ± 9.97 years) were analysed up to 5-year follow-up. A greater lymphocyte decrease was associated with a lower risk of NEDA-3 status loss (hazard ratio 0.87, P = 0.01). A worse outcome in patients with lower ALC drop (<11.5%), compared with higher tertiles (11.5%-40.5% and >40.5%), was observed (P = 0.008). The nadir of ALC drop (-33.6%) and 35% of grade III lymphopaenia cases occurred after 12 months of treatment. CONCLUSION: A higher lymphocyte count drop at 6 months is related to better outcomes in DMF-treated patients. A careful ALC monitoring should be pursued up to 24 months of treatment.

Pregnancy effect on disease activity in women with multiple sclerosis treated with cladribine.

INTRODUCTION: Cladribine is an oral immune reconstitution therapy for relapsing multiple sclerosis (RMS). Hormonal and immune changes are responsible for the decline of disease activity in the third trimester of pregnancy and disease reactivation in the early post-partum period.We investigate the impact of pregnancy on disease activity in women with MS who conceived after cladribine treatment. METHODS: We recruited women of childbearing age with relapsing-remitting MS (RRMS) who became pregnant or not after being treated with cladribine. For both groups, demographic, clinical and radiological data were collected 1 year before and after treatment during a mean follow-up of 3.53 years. We compared disease activity over time between groups using variance analysis for repeated measures. RESULTS: 48 childbearing women were included. 25 women had a pregnancy after a mean of 1.75 years from the first treatment cycle. Women with or without pregnancy did not differ in demographics or pre-cladribine disease activity. No significant differences in disease activity or EDSS worsening were found between women with or without pregnancy. DISCUSSION: Our findings suggest that pregnancy does not appear to influence disease activity and disability in women previously treated with cladribine; further studies with larger numbers and longer follow-up are needed to confirm this finding.

Sleep-related disorders and their relationship with MRI findings in multiple sclerosis.

Sleep-related disorders have been reported to have a higher prevalence in multiple sclerosis (MS) than in the general population. They are often undervalued for the presence of more severe physical problems and the occurrence at night, without a direct observation in common clinical practice, but if not recognized and treated they can negatively affect the quality of life causing daytime drowsiness and worsening fatigue. Sleep related disorders most commonly reported in MS are as follows: insomnia, sleep-related breathing disorders (SRBD), restless legs syndrome (RLS) and periodic limb movement disorders (PLMD). Secondary narcolepsy, REM sleep behavior disorder (RBD) and propriospinal myoclonus have been also described in some case reports or series. The purpose of this review is to correlate the more common sleep disturbances in MS patients to the involvement of specific brain regions, analyzing their relationship with MRI findings. While insomnia is usually secondary to other disabling symptoms such as nocturia or pain, SRBD, RLS, narcolepsy, RBD and propriospinal myoclonus in MS patients can be the consequence of an injury of specific central nervous system (CNS) areas. Lesions in the pontine tegmentum and the dorsal medulla have been associated with SRBD, spinal cord lesions or atrophy with RLS, bilateral lesions in the lateral hypothalamus with narcolepsy-like symptoms, lesions in the dorsal pontine tegmentum with RBD and intramedullary demyelinating plaques in spinal cord with propriospinal myoclonus. MS specialists and general neurologists should be aware of these comorbidities since neuroimaging, which is routinely performed in MS, could provide helpful clinical indications on patients with secondary sleep-related disorders and to categorize symptomatic patients who need to underdo more in-depth sleep studies.

Cyclooxygenase 2 promotes cell survival by stimulation of dynein light chain expression and inhibition of neuronal nitric oxide synthase activity.

Cyclooxygenase 2 (COX-2) inhibits nerve growth factor (NGF) withdrawal apoptosis in differentiated PC12 cells. The inhibition of apoptosis by COX-2 was concomitant with prevention of caspase 3 activation. To understand how COX-2 prevents apoptosis, we used cDNA expression arrays to determine whether COX-2 regulates differential expression of apoptosis-related genes. The expression of dynein light chain (DLC) (also known as protein inhibitor of neuronal nitric oxide synthase [PIN]) was significantly stimulated in PC12 cells overexpressing COX-2. The COX-2-dependent stimulation of DLC expression was, at least in part, mediated by prostaglandin E(2). Overexpression of DLC also inhibited NGF withdrawal apoptosis in differentiated PC12 cells. Stimulation of DLC expression resulted in an increased association of DLC/PIN with neuronal nitric oxide synthase (nNOS), thereby reducing nNOS activity. Furthermore, nNOS expression and activity were significantly increased in differentiated PC12 cells after NGF withdrawal. This increased nNOS activity as well as increased nNOS dimer after NGF withdrawal were inhibited by COX-2 or DLC/PIN overexpression. An nNOS inhibitor or a membrane-permeable superoxide dismutase (SOD) mimetic protected differentiated PC12 cells from NGF withdrawal apoptosis. In contrast, NO donors induced apoptosis in differentiated PC12 cells and potentiated apoptosis induced by NGF withdrawal. The protective effects of COX-2 on apoptosis induced by NGF withdrawal were also overcome by NO donors. These findings suggest that COX-2 promotes cell survival by a mechanism linking increased expression of prosurvival genes coupled to inhibition of NO- and superoxide-mediated apoptosis.

Site and type of craniopharyngiomas impact differently on 24-hour circadian rhythms and surgical outcome. A neurophysiological evaluation.

This study aimed to quantify 24h body core temperature (BcT°) and sleep-wake cycle rhythm alterations in craniopharyngioma (CP) patients and to identify markers related to the postsurgical outcomes. Ten consecutive CP patients underwent neuroradiological, endocrinological and ophthalmological evaluations, 24h BcT° and sleep-wake cycle recordings before and after endoscopic endonasal surgery. The sample included four women and six men. Nocturnal sleep efficiency was pathologically reduced in eight patients before surgery. Seven out of ten patients presented one to three daytime naps. 24h BcT° rhythm was pathological in six out of ten cases. Post-surgery sleep efficiency normalized in four out of eight patients, whereas nine out of ten patients presented with two to six longer daytime naps. Diurnal naps were mainly present in patients showing pre-operative involvement of the third ventricle floor. 24h BcT° remained pathological in only one out of six cases, returned to normal in two and improved in three. 24h BcT° rhythm improved more in papillary CPs than in adamantomatous CPs. Our data confirmed that both CP and surgery frequently disrupt the sleep-wake cycle and BcT° rhythms. Tumour location and histotype may be related to a worse postsurgical outcome. Therefore, in-depth investigation including circadian monitoring is crucial for surgical outcome.

Cardiac autonomic tone during trandolapril-irbesartan low-dose combined therapy in hypertension: a pilot project.

Pharmacological and clinical studies on the effects of angiotensin-converting enzyme (ACE) inhibitors support the idea of a central role played Angiotensin II which is able to cause cardiovascular and renal diseases also independently of its blood pressure elevating effects. The present investigation was aimed at evaluating the effect(s) of three different pharmacological regimens on both blood pressure and sympathetic drive in uncomplicated essential hypertension, by means of blood pressure laboratory measurements and ambulatory monitoring, 24-h heart rate variability and plasma noradrenaline levels. Thus, an ACE-inhibitor monotherapy (trandolapril, 2 mg/day), an AT(1)-receptor antagonist monotherapy (irbesartan, 300 mg/day), their low-dose combination (0.5 mg/day plus 150 mg/day, respectively) and placebo were given, in a randomised, single-blind, crossover fashion for a period of 3 weeks each to 12 mild essential hypertensives. Power spectral analysis (short recordings) and noradrenaline measurements were also performed in the supine position and after a postural challenge (60 degrees head-up tilting test: HUT). The low-dose combination therapy induced the greatest reduction in LF component and in LF/HF ratio, both in the resting and tilted positions, as well as in blood pressure. However, the physiological autonomic response to HUT was maintained. Noradrenaline plasma levels were lower after the combined therapy than after each drug alone. Our data demonstrate that in mild and uncomplicated essential hypertension, the chronic low-dose combination therapy with an ACE-inhibitor and an AT(1)-antagonist is more effective than the recommended full-dose monotherapy with either drug in influencing the autonomic regulation of the heart, suggesting a relative reduction in sympathetic drive both at cardiac and systemic levels.

Update on ascites and hepatorenal syndrome.

Ascites is the most common complication occurring during liver cirrhosis. Even if a significant decrease in renal clearance may be observed in the first step of chronic active liver disease, renal impairment, at times complicated by the typical signs of hepatorenal syndrome, occurs only in patients with ascites, especially when tense and refractory. Experimental and clinical data seem to suggest a primary sodium and water retention in the pathogenesis of ascites, in the presence of an intrahepatic increase of hydrostatic pressure, which, by itself, physiologically occurs during digestion. Abnormal sodium and water handling leads to plasma volume expansion, followed by decreased peripheral vascular resistance and increased cardiac output. This second step is in agreement with the peripheral arterial vasodilation hypothesis, depicted by an increase in total blood volume, but with a decreased effective arterial blood volume. This discrepancy leads to the activation of the sympathetic nervous and renin-angiotensin-aldosterone systems associated with the progressive activation of the renal autacoid systems, especially, that of the arachidonic acid. During advanced cirrhosis, renal impairment becomes more sustained and renal autacoid vasodilating substances are less available, possibly due to a progressive exhaustion of these systems. At the same time ascites becomes refractory inasmuch as it is no longer responsive to diuretic treatment. Various pathogenetic mechanisms leading to refractory ascites are mentioned. Finally, several treatment approaches to overcome the reduced effectiveness of diuretic therapy are cited. Paracentesis, together with simultaneous administration of human albumin or other plasma expanders is the main common approach to treat refractory ascites and to avoid a further decrease in renal failure. Other effective tools are: administration of terlipressin together with albumin, implantation of the Le Veen shunt, surgical porto-systemic shunting or transjugular intrahepatic portosystemic stent-shunt, or orthotopic liver transplantation, according to the conditions of the individual patient.

Vascular reserve in the lower limbs of cirrhotic patients: a duplex Doppler ultrasound study.

AIM: To evaluate femoral artery impedance at rest and during reactive hyperaemia. PATIENTS: Study population comprised 11 cirrhotic patients without ascites, 10 with ascites and 16 age- and sex-matched healthy subjects. METHODS: Echocardiographic assessment of systemic haemodynamics; duplex Doppler ultrasound measurement of femoral artery pulsatility index and vascular reserve [pulsatility index rest/pulsatility index hyperaemia). RESULTS: Cirrhotic patients had elevated cardiac index and low systemic vascular resistance. Pulsatility index (right femoral artery) was not statistically different either at rest or after reactive hyperaemia (controls: rest 10.6 +/- 0.4, hyperaemia 2.6 +/- 0.2; compensated cirrhosis: rest 10.1 +/- 0.8, hyperaemia 3.4 +/- 0.4; ascitic cirrhosis: rest 11.4 +/- 1.6, hyperaemia 2.9 +/- 0.4. Vascular reserve was 4.38 +/- 0.35 in controls, 3.33 +/- 0.39 in compensated and 4.70 +/- 0.89 in ascitic cirrhosis (p = not significant). No correlation was found between systemic haemodynamic parameters and either pulsatility index or vascular reserve. CONCLUSIONS: The lower limb vascular reserve is preserved in cirrhosis.

Refractory ascites: definition, pathogenesis and treatment.

Refractory ascites, that is ascites which cannot be mobilized by low sodium diet and maximal doses of diuretics (up to 400 mg spironolactone or potassium canrenoate and 160 mg furosemide per day), occurs in 5% of cirrhotic patients with ascites. The development of refractory ascites is mainly related to the progression of arterial vasodilation-mediated vascular underfilling and to the imbalance between reduced synthesis of renal vasodilating factors (especially renal prostaglandins) and extreme activation of vasoconstricting systems. Further features include increased sodium reabsorption in the proximal tubule and altered pharmacokinetics and pharmacodynamics of diuretics. In patients with impaired renal function (as is the case for most patients with refractory ascites), the marked reduction of renal perfusion and glomerular filtration rate, with the consequent decrease of filtered sodium load, becomes the main pathogenetic factor. The principal therapeutic options for refractory ascites include repeated paracentesis and implantation of the LeVeen shunt. Paracentesis is a rapid and safe procedure to remove ascites, but it does not correct sodium retention. Ascites recurrence, therefore, may occur after a brief interval. The LeVeen shunt allows for better long-term control of ascites, but severe complications may supervene, and shunt occlusion is common. Neither therapeutic procedure improves survival. Different experimental therapeutic procedures have been proposed. Administration of ornipressin corrects hyperdynamic circulation and improves renal function. Thromboxane synthase inhibitors, by reducing renal synthesis of thromboxane A2, potentiate the diuretic and natriuretic response to furosemide. More invasive procedures, including portosystemic shunt and transjugular intrahepatic stent, are rarely used in the treatment of refractory ascites.(ABSTRACT TRUNCATED AT 250 WORDS)

[Effects of drinking Tettuccio di Montecatini mineral waters on gallbladder emptying and functioning hepatic mass]. / Effetti sullo svuotamento colecistico e sulla massa epatica funzionante dell'assunzione di acqua termale Tettuccio di Montecatini.

Real time echography and galactose loading test were used to evaluate changes in gallbladder emptying and functioning hepatic mass in dyspeptic patients after drinking Tettuccio mineral water. The above tests showed that Tettuccio mineral water is apt to provoke a rapid, intense gallbladder contraction which appeared to be slightly more protracted when the tests were repeated after two weeks of treatment with the mineral water. This action appears to be due to the composition of the alkaline sulfate saline water rather than to its osmolar concentration since the water is more effective in bringing about gallbladder emptying than saline solutions of higher osmolarity.

Activation of extracellular signal-regulated kinase 1/2 inhibits type I collagen expression by human skin fibroblasts.

Treatment with the lipid second messenger, ceramide, activates extracellular signal-regulated kinase-1/2 (ERK1/2), c-Jun N-terminal kinase, and p38 in human skin fibroblasts and induces their collagenase-1 expression (Reunanen, N., Westermarck, J., Häkkinen, L., Holmström, T. H., Elo, I., Eriksson, J. E., and Kähäri, V.-M. (1998) J. Biol. Chem. 273, 5137-5145). Here we show that C(2)-ceramide inhibits expression of type I and III collagen mRNAs in dermal fibroblasts, suppresses proalpha2(I) collagen promoter activity, and reduces stability of type I collagen mRNAs. The down-regulatory effect of C(2)-ceramide on type I collagen mRNA levels was abrogated by protein kinase C inhibitors H7, staurosporine, and Ro-31-8220 and potently inhibited by a combination of MEK1,2 inhibitor PD98059 and p38 inhibitor SB203580. Activation of ERK1/2 by adenovirus-mediated expression of constitutively active MEK1 resulted in marked down-regulation of type I collagen mRNA levels and production in fibroblasts, whereas activation of p38 by constitutively active MAPK kinase-3b and MAPK kinase-6b slightly up-regulated type I collagen expression. These results identify the ERK1/2 signaling cascade as a potent negative regulatory pathway with respect to type I collagen expression in fibroblasts, suggesting that it mediates inhibition of collagen production in response to mitogenic stimulation and transformation.

Biphasic activation of p21ras by endothelin-1 sequentially activates the ERK cascade and phosphatidylinositol 3-kinase.

Endothelin-1 (ET-1) induces cell proliferation and differentiation through multiple G-protein-linked signaling systems, including p21ras activation. Whereas p21ras activation and desensitization by receptor tyrosine kinases have been extensively investigated, the kinetics of p21ras activation induced by engagement of G-protein-coupled receptors remains to be fully elucidated. In the present study we show that ET-1 induces a biphasic activation of p21ras in rat glomerular mesangial cells. The first peak of activation of p21ras, at 2-5 min, is mediated by immediate association of phosphorylated Shc with the guanosine exchange factor Sos1 via the adaptor protein Grb2. This initial activation of p21ras results in activation of the extracellular signal-regulated kinase (ERK) cascade. We demonstrate that ET-1 signaling elicits a negative feedback mechanism, modulating p21ras activity through ERK-dependent Sos1 phosphorylation, findings which were confirmed using an adenovirus MEK construct. Subsequent to p21ras and ERK deactivation, Sos1 reverts to the non-phosphorylated condition, enabling it to bind again to the Grb2/Shc complex, which is stabilized by persistent Shc phosphorylation. However, the resulting secondary activation of p21ras at 30 min does not lead to ERK activation, correlating with intensive, ET-1-induced expression of MAP kinase phosphatase-1, but does result in increased p21ras-associated phosphatidylinositol 3-kinase activity. Our data provide evidence that ET-1-induced biphasic p21ras activation causes sequential stimulation of divergent downstream signaling pathways.

Changes in the production of nitric oxide and superoxide by inflammatory cells in liver cirrhosis.

Superoxide (O2-) and nitric oxide (NO) production by polymorphonuclear leukocyte (PMNs) and monocytes in patients with liver cirrhosis were evaluated. PMNs obtained from cirrhotic patients were less effective than those from controls in producing O2- after stimulation with opsonized zymosan, while they were more effective in producing NO, as shown by the inhibition of platelet aggregation and by the increase in cGMP content. NO synthase activity was higher in leukocytes from cirrhotic patients than in controls. A correlation was found between the cardiac index and the observed changes in the inflammatory cells.

Pathogenesis and treatment of ascites in hepatic cirrhosis.

In cirrhosis of the liver structural distortion of the sinusoidal vessels is the major factor responsible for the increase in portal venous pressure and the development of abdominal ascites. The mechanisms by which advanced cirrhosis of the liver leads to widespread changes in the systemic circulation including vasodilatation, increased cardiac output and expanded plasma volume, together with activation of a range of antinatriuretic and natriuretic factors, are unclear. Several hypotheses have been proposed to explain these pathophysiological consequences, including underfilling of the systemic arterial system, overflow and peripheral vasodilatation, with a decrease in effective arterial blood volume. The evidence for and against these hypotheses is critically examined. In patients with hepatic cirrhosis complicated by ascites, increased intrarenal release of vasodilating prostaglandins may assist in sustaining renal blood flow and glomerular filtration rate by counteracting the vasoconstrictor effects of noradrenaline and angiotensin II. In advanced stages of the syndrome, cirrhotic ascites may become refractory to medical treatment. In this situation renal function becomes progressively impaired and eventually acute renal failure, so-called hepatorenal syndrome, supervenes due to intense renal vasoconstriction and opening of intrarenal arteriovenous shunts. The progressive renal vasoconstriction may also be accentuated by the reduced synthesis of renal vasodilating prostaglandins. The medical treatment of ascites is based on bed-rest, a low-sodium diet and administration of aldosterone antagonists and loop diuretics. Patients who are refractory to such therapy may be further treated by paracentesis or by the LeVeen shunt, though the long-term results of these physical therapies are unsatisfactory.

Induction of prostaglandin endoperoxide synthase 2 by mitogen-activated protein kinase cascades.

Prostaglandin endoperoxide synthase (PGHS) catalyses the rate-limiting step in the formation of prostaglandin and thromboxane eicosanoids from arachidonic acid released by phospholipase A(2). Two forms of PGHS exist, PGHS-1 and PGHS-2. PGHS-2, normally absent from cells, is rapidly expressed in response to a wide variety of stimuli and has been implicated in the pathogenesis of colon cancer and several inflammatory diseases. The three principal mitogen-activated protein kinase (MAPK) pathways are the extracellular signal-regulated protein kinase (ERK), the c-Jun N-terminal kinase (JNK) cascade and the p38-MAPK cascade. The present study was undertaken to investigate the putative involvement of the MAPK cascades in PGHS-2 induction. The potential role of ERK in PGHS-2 up-regulation was assessed by using cell lines expressing, both stably and after adenoviral infection, constitutively active forms of its upstream activator MAPK/ERK kinase (MEK1). The possible involvement of JNK and p38-MAPK in positively modulating PGHS-2 transcription was investigated by using adenovirus-mediated transfer of active forms of their respective specific upstream kinases, mitogen-activated protein kinase kinase (MKK) 7 and MKK3/MKK6. ERK activation promoted the induction of PGHS-2 mRNA and protein. Similarly, activation of JNK by Ad-MKK7D and p38-MAPK by Ad-MKK3bE/Ad-MKK6bE resulted in the increased expression of PGHS-2. These results provide evidence that activation of all three of the major mammalian MAPK leads to the induction of PGHS-2 mRNA and protein. Because PGHS-2 is up-regulated by a diverse range of stimuli, both mitogenic and stress-evoking, these results provide evidence that the convergence point of these stimuli could be the activation of one or more MAPK cascade(s).

Endothelin-1 induces serine phosphorylation of the adaptor protein p66Shc and its association with 14-3-3 protein in glomerular mesangial cells.

Endothelin-1 (ET-1) is a vasoconstrictor peptide known to be a potent mitogen for glomerular mesangial cells (GMC). In the current study, it is demonstrated that ET-1 treatment of GMC results in serine phosphorylation of the 66-kDa isoform of the adapter protein Shc (p66(Shc)). ET-1-induced serine phosphorylation of p66(Shc) requires activation of the mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) signaling module and is efficiently inhibited by both a MAPK/ERK kinase (MEK)-selective inhibitor and adenovirus-mediated transfer of a dominant interfering MEK1 mutant. Furthermore, adenovirus-mediated transfer of a constitutively active MEK1 mutant was found to markedly increase p66(Shc) serine phosphorylation. Adenoviruses encoding constitutively active mutants of MAPK kinases 3 and 6 (upstream kinases of p38(MAPK)) and 7 (upstream kinase of c-Jun NH(2)-terminal kinase) failed to induce serine phosphorylation of this adaptor protein. Serine phosphorylation of p66(Shc) resulted in its association with the serine binding motif-containing protein 14-3-3. ET-1-induced phosphorylation of a serine encompassed in the 14-3-3 binding motif of p66(Shc) was confirmed in experiments employing anti-phospho-14-3-3 binding motif antibodies. These studies are the first to demonstrate that G protein-coupled receptors stimulate serine phosphorylation of p66(Shc) and the first to report the formation of a signaling complex between p66(Shc) and 14-3-3.

Torasemide in the treatment of patients with cirrhosis and ascites.

The effects of torasemide (20 mg/day) and furosemide (50 mg/day), each given over 4 days, were compared in a randomized and crossover study carried out in seven patients with cirrhosis and tense ascites. Patients also received a low-sodium (40 mmol/day) diet and the aldosterone antagonist, potassium canrenoate (100 mg b.i.d.). Torasemide induced a remarkably higher natriuretic (120 +/- 15 vs. 33 +/- 6 mmol/day, p < 0.02) and diuretic (1450 +/- 63 vs. 900 +/- 58 ml, p < 0.005) effect than furosemide. Body weight loss was also significantly higher (2.5 +/- 1.6 vs. 0.2 +/- 1.3 kg, p < 0.01) during the torasemide period. Kaliuresis was similar during the two treatment periods, despite the striking differences observed in natriuresis. Neither torasemide nor furosemide induced any significant change in serum electrolyte or creatinine concentrations, or in ammonia levels. The results of this study indicate that torasemide is suitable for the treatment of sodium retention in patients with cirrhosis and ascites.

Loop diuretic therapy in liver cirrhosis with ascites.

Medical treatment of ascites is aimed at reverting sodium retention, that is, at creating a negative sodium balance to relieve ascites. Bed rest and low-sodium diet induce the disappearance of ascites in about 10% of patients. Loop diuretics and aldosterone antagonists must be administered to the patients not responding to the previous regimen. Available evidence indicates that aldosterone antagonists are the first-choice drugs, as these substances are more effective than furosemide. Nevertheless, loop diuretics potentiate the effects of aldosterone antagonists. The reduced efficacy of furosemide in these patients, when compared with that of spironolactone, may be related to an impairment of both pharmacodynamics and pharmacokinetics. In fact, most sodium not reabsorbed in Henle's loop, due to the action of furosemide, is subsequently taken up in the distal nephron because of hyperaldosteronism. A further mechanism of resistance may be related to an impaired excretion of furosemide into the tubular lumen. The use of diuretics in the treatment of ascites is associated with several side effects, including prerenal azotemia, hepatic encephalopathy, and electrolyte and acid-base disorders. A stepped-care approach, together with careful monitoring of patients, is the best way to reduce the incidence of these complications. Ethacrynic acid has been shown to be highly effective in the treatment of ascites, even in patients refractory to other diuretics, but its use is associated with a high incidence of hypokalemia and hypochloremic alkalosis. Bumetanide and piretanide are comparable to furosemide, in terms of both efficacy and side effects.(ABSTRACT TRUNCATED AT 250 WORDS)

Activation of extracellular signal-regulated protein kinase1,2 results in down-regulation of decorin expression in fibroblasts.

Decorin is a small leucine-rich extracellular matrix proteoglycan, the expression of which is down-regulated in proliferating and malignantly transformed cells. In the present study we show that the expression of decorin in fibroblasts is suppressed by epidermal growth factor (EGF) and PMA, and that the effect of both is potently inhibited by blocking the extracellular signal-regulated protein kinase (ERK)1,2 signalling pathway (Raf/MEK1,2/ERK1,2) with the specific MAPK/ERK kinase (MEK)1,2 inhibitor, PD98059. In addition, specific activation of ERK1,2 by adenovirus-mediated expression of constitutively active MEK1 in dermal fibroblasts results in marked reduction in decorin mRNA abundance and production. Co-transfection of NIH-3T3 fibroblasts with human decorin promoter/chloramphenicol acetyltransferase (CAT) construct (pDEC--879/CAT) in combination with the expression vectors for constitutively active Raf-1 and MEK1 markedly suppressed decorin promoter activity. Co-transfections of human decorin promoter 5'-deletion constructs with constitutively active MEK1 expression vector identified the region -278 to -188 as essential for ERK1,2 mediated down-regulation of decorin promoter activity. These results show that activation of the ERK1,2 signalling pathway by a mitogenic growth factor, a tumour promoter or transformation suppresses decorin gene expression in fibroblasts, which in turn may promote proliferation and migration of normal and malignant cells.