Hemodynamic, metabolic and hormonal responses to oral glibenclamide in patients with cirrhosis receiving glucose

BACKGROUND

In patients with cirrhosis, glucose may induce splanchnic and renal vasodilation. Since the antidiabetic sulfonylurea glibenclamide is known to induce splanchnic and renal vasoconstriction in portal hypertensive animals, this drug may inhibit glucose-induced hemodynamic responses in patients with cirrhosis. The aim of the present study was to investigate, in patients with cirrhosis, the short-term effects of glibenclamide on hemodynamic and humoral responses to glucose.

METHODS

Patients were randomly assigned to receive either glibenclamide (5-mg tablet) or a placebo. All patients received an infusion of 10% glucose (62.5 ml/h for 12 h) that was started at the same time as glibenclamide or placebo administration. Studies were performed prior to and 90 min after glibenclamide or placebo.

RESULTS

Glibenclamide (i.e. glibenclamide plus glucose) significantly increased plasma insulin concentrations and glycemia while placebo (i.e. glucose alone) significantly increased glycemia but did not change plasma insulin levels. Glibenclamide did not significantly change the hepatic venous pressure gradient while this value was significantly increased following glucose alone. Glibenclamide did not significantly change renal blood flow and glomerular filtration rate while glucose alone significantly increased renal blood flow without affecting the glomerular filtration rate. Glibenclamide significantly decreased cardiac index while glucose alone did not change this value.

CONCLUSIONS

In patients with cirrhosis receiving glucose, glibenclamide blunted glucose-induced splanchnic and renal vasodilation. In addition, glibenclamide per se induced a decrease in cardiac index. These findings should be taken into account when glibenclamide is administered to patients with cirrhosis and type 2 diabetes.

Relationships between haemodynamic alterations and the development of ascites or refractory ascites in patients with cirrhosis

OBJECTIVE

In patients with cirrhosis, the relationships between haemodynamic alterations and the development of ascites or the occurrence of refractory ascites are unknown. The aim of the present study was to compare haemodynamic measurements obtained in patients with non-refractory ascites to haemodynamic measurements obtained in patients without ascites and in patients with refractory ascites.

METHODS

A cohort of 121 patients was prospectively studied, of whom 29 patients did not have ascites, 45 had non-refractory ascites and 47 had refractory ascites. Splanchnic, renal and systemic haemodynamics were measured in all patients.

RESULTS

The hepatic venous pressure gradient was significantly higher in patients with non-refractory ascites than in patients without ascites (18.5 +/- 0.8 mmHg versus 15.8 +/- 0.7 mmHg). Renal and systemic haemodynamics did not significantly differ between patients with non-refractory ascites and patients without ascites. The glomerular filtration rate and renal blood flow were significantly lower in patients with refractory ascites than in patients with non-refractory ascites (77 +/- 4 versus 107 +/- 5 ml/min and 867 +/- 62 versus 1,008 +/- 68 ml/min, respectively). Splanchnic and systemic haemodynamics did not significantly differ between patients with refractory ascites and patients with non-refractory ascites.

CONCLUSIONS

In patients with cirrhosis, an increase in portal hypertension was the sole haemodynamic alteration related to the development of ascites. Renal vasoconstriction (and subsequent renal hypoperfusion and hypofiltration) was the only haemodynamic alteration related to the occurrence of refractory ascites. The development of ascites or refractory ascites was not associated with any alteration in systemic haemodynamics.

Regulation of splanchnic perfusion

In splanchnic arteries, vasodilators decrease the cytosolic free calcium concentration ([Ca(2+)]i) by inducing Ca(2+)sequestration and extrusion, by limiting the entry of extracellular Ca(2+)via L-type Ca(2+)channels and by decreasing the agonist-induced mobilization of intracellular Ca(2+). Cyclic GMP kinase and membrane hyperpolarization are important mediators of the decrease in [Ca(2+)]i. Vasoconstrictors increase [Ca(2+)]i by mobilizing intracellular Ca(2+)from the sarcoplasmic reticulum and by stimulating extracellular Ca(2+)entry via L-type Ca(2+)channels. Activation of G proteins, inositol trisphosphate, diacylglycerol and membrane depolarization are important mediators of the increase in [Ca(2+)]i.

Changes of biogenic amine levels in haemolymph during diapausing and non-diapausing status in Pieris brassicae L

During the larval development of Pieris brassicae, photoperiod status induces either direct (non-diapausing) development or diapausing development. Biogenic amines such as dopamine and serotonin and their derivatives may be implicated in the physiological control and adaptation of these insects to different photoperiods. High performance liquid chromatography coupled with electrochemical detection was used to measure biogenic amine concentrations in insect haemolymph in different photoperiod conditions. At the end of the higher photosensitivity phase, dopamine levels were two-fold higher in diapausing (0.914 pmol/microl+/-0.025) as compared to non-diapausing insects (0.415 pmol/microl+/-0.02; P<0.001). Globally, dopamine catabolites are found in higher levels in non-diapausing insects (in prepupa, near seven times more for NADA, and 25 times more for DOPAc), thus indicating a higher dopamine turn-over. Serotonin levels were detected only at the beginning of this instar in diapausing insects but not in direct development insects. During pupal life, dopamine levels were significantly higher in diapausing than in non-diapausing insects (in 3-day pupae, dopamine was 28 times higher), and remained at high levels throughout diapausing life. At the beginning of diapause, serotonin levels were higher in diapausing insects than in non-diapausing insects (in 3-day pupae, serotonin was 13 times higher). These levels decreased in the middle of diapause period, and then increased just before its breaking. Dopamine and serotonin levels presented the typical kinetics of diapause development and may be used as an indicator of the evolution of diapause status.

Aortic hyporeactivity to norepinephrine induced by lipopolysaccharide in cirrhotic rats: beneficial effects of a non-steroidal anti-inflammatory drug coupled with a nitric oxide donor

BACKGROUND AND AIMS

Cirrhosis is associated with a hyperdynamic syndrome and arterial vasodilation that is related to nitric oxide (NO) synthase 3 overactivity. Septic shock is frequently associated with cirrhosis and with a vascular induction of NO synthase 2. The aims of this study were to compare the effects of lipopolysaccharide (LPS) in normal and cirrhotic rats, and to test the effects of a nonsteroidal anti-inflammatory drug (NSAID) coupled with a (NO) donor.

METHODS

Cirrhotic rats received NO-flurbiprofen, flurbiprofen or vehicle followed by LPS or placebo 15 min later. The heart rate and mean arterial pressure of rats were monitered for 5 h. Thoracic aortic rings were removed and contracted with the use of norepinephrine. Nitric oxide synthase activity was measured in the aorta and stomach of cirrhotic rats.

RESULTS

Arterial pressure decreased in cirrhotic rats in the vehicle/LPS and flurbiprofen/LPS groups. After LPS administration, the heart rate of rats increased in all groups. In the aortic rings, LPS induced hyporeactivity to norepinephrine in all groups except the NO-flurbiprofen group. This hyporeactivity was abolished after preincubation with Nw-nitro-L-arginine (L-NNA). Nw-nitro-L-arginine had no effect on norepinephrine-induced vasoconstriction in the NO-flurbiprofen/LPS group. Nitric oxide synthase 2 activity in the stomach and aorta of cirrhotic rats was increased in each group except in the NO-flurbiprofen group after LPS administration. Pretreatment with NO NSAID prevented aortic hyporeactivity to norepinephrine in cirrhotic rats treated with LPS as it probably inhibited the NO synthase 2 induction.

CONCLUSIONS

These findings suggest that NO-flurbiprofen has a beneficial hemodynamic effect in cirrhotic rats and may help to prevent LPS aortic hyporeactivity.

Evidence for an endothelium-derived hyperpolarizing factor in the superior mesenteric artery from rats with cirrhosis

In cirrhosis, in splanchnic arteries, endothelium-dependent relaxation may persist even if overactive nitric oxide synthase (NOS) and cyclooxygenase (COX) are inhibited. In normal arteries, a significant endothelium-dependent relaxation to acetylcholine persists after NOS/COX inhibition. This relaxation is caused by smooth muscle cell (SMC) membrane hyperpolarization, which is sensitive to a combination of the potassium channel blockers apamin and charybdotoxin, and is mediated by an endothelium-derived hyperpolarizing factor (EDHF). The aim of this study was to detect EDHF and evaluate its pathophysiologic role in isolated superior mesenteric arteries from cirrhotic rats. Arterial rings were obtained and exposed to N(w)-nitro-L-arginine (L-NNA, a NOS inhibitor) and indomethacin (a COX inhibitor). Acetylcholine-induced membrane potential responses and concentration-response curves to the relaxant of acetylcholine were obtained with and without apamin plus charybdotoxin. Acetylcholine-induced responses were measured in certain rings from endothelium-denuded arteries. Contractions caused by the alpha(1)-adrenoceptor agonist phenylephrine were obtained in cirrhotic and normal rings with and without apamin and charybdotoxin. Significant acetylcholine-induced, endothelium-dependent, apamin- and charybdotoxin-sensitive, SMC membrane hyperpolarization and relaxation were found. An apamin- and charybdotoxin-sensitive hyporesponsiveness to the contractile action of phenylephrine was found in cirrhotic rings. In conclusion, in cirrhotic rats, in the superior mesenteric artery exposed to NOS/COX-inhibitors, an EDHF exists that may replace NOS/COX products to induce endothelium-dependent arterial relaxation.

Molecular characterization of environmental mycobacterium strains by PCR-restriction fragment length polymorphism of hsp65 and by sequencing of hsp65, and of 16S and ITS1 rDNA

Fifteen mycobacterial strains from the environment, not clearly identifiable by biochemical properties, were analyzed with molecular markers: PCR-restriction enzyme analysis of hsp65 and sequencing of hsp65, and of the internal transcribed spacer 1 (ITS1) and 16S rDNA. The 16S rDNA sequencing closely related the strains to a slow-growing mycobacterial group including Mycobacterium simiae, Mycobacterium lentiflavum, Mycobacterium genavense, Mycobacterium triplex and Mycobacterium heidelbergense. A stretch of T bases at the level of 16S rDNA enabled the separation of M. simiae and M. lentifiavum from M. genavense, M. triplex and M. heidelbergense; hence the attribution of some environmental strains to the first or second group. But the distances between the two clades were very short and the relative positions of environmental strains and of reference strains were not resolved in terms of node robustness (low bootstrap values) in the distance tree. However, the hsp65 restriction profiles suggested assigning six strains to the M. lentiflavum species, although these strains had been found closely related to M. genavense and M. triplex from 16S rDNA nucleotide signatures. The clustering of environmental strains into the same three clusters was deduced from analysis of three sequence data (hsp65, and ITS1 and 16S rDNA), but the taxonomic affiliation of environmental strains to reference strains remained tentative. Among environmental strains and reference strains, the distances found from hsp65 sequences had the same amplitude as those found between different strains of Mycobacterium gordonae. From ITS1 rDNA sequences, the distances found between the strains of the Mycobacterium avium complex also had the same amplitude as those found between environmental strains and reference strains. From our results, it appears that the environmental strains and the reference strains could constitute a complex of subspecies or closely related species. Their taxonomic status must be confirmed by DNA/DNA hybridization experiments.

Effects of lipopolysaccharide on TNF-alpha production, hepatic NOS2 activity, and hepatic toxicity in rats with cirrhosis

BACKGROUND/AIMS

Septic shock results in high mortality in patients with cirrhosis. Nitric oxide synthase 2 (NOS2) is induced by bacterial lipopolysaccharides (LPS) and plays a major role in the inflammatory response to bacterial infections. Little is known about the regulation of NOS2 in cirrhosis under septic conditions. Thus, the aim of this study was to determine tissue NOS2 activity, serum nitrate and tumor necrosis factor (TNF-alpha) levels and hepatic toxicity in cirrhotic rats after LPS administration.

METHODS

Serum nitrates, TNF-alpha and transaminases were determined after LPS-administration in rats with secondary biliary cirrhosis and in sham-operated rats. Liver, lung, aortic and peritoneal macrophage NOS2 activities were determined by converting L[14C] arginine into L[14C] citrulline in a calcium free medium. Nitrate and TNF-alpha production were determined in a culture medium of peritoneal macrophages after in vivo LPS administration.

RESULTS

LPS (1.5 mg/kg) induced 50% mortality in cirrhotic rats and no mortality in sham-operated rats. After LPS, TNF-alpha, nitrate and transaminase levels were significantly higher in cirrhotic rats compared to sham-operated rats. After LPS administration, there were no differences in NOS2 activity in the aorta, lungs, or peritoneal macrophages of the two groups, whereas NOS2 activity was significantly higher in the cirrhotic liver compared to the normal liver.

CONCLUSIONS

In rats with cirrhosis, LPS administration induces higher mortality, hepatic toxicity, hepatic NOS2 activation and TNF-alpha release than in sham-operated rats. These results confirm the harmful role of septic shock in liver disease.

Characteristics of the cholesterol efflux induced by novel seminal phospholipid-binding proteins

Our recent results indicated that the major proteins of bovine seminal plasma (collectively called BSP proteins) stimulate cholesterol efflux from fibroblasts and that this process shows many differences compared to the efflux induced by apolipoprotein A-I (apoA-I)-containing lipoproteins. The present study was undertaken to investigate the BSP-mediated efflux mechanism. Compared to the slow and constant rate of cholesterol efflux induced by apoA-I-containing lipoproteins, the BSP proteins stimulated a rapid efflux that gradually reached a plateau. The addition of purified BSP proteins after the establishment of the plateau resulted in a further cholesterol efflux indicating that cellular cholesterol was still available for efflux. Incubation of unlabeled fibroblast culture with the spent medium containing BSP-generated lipid ([(3)H]cholesterol) particles obtained after the establishment of the plateau did not result in any cholesterol influx. Therefore, the plateau did not correspond to an equilibrium of the radiolabel between the medium and the cells but rather to a saturation of the efflux particles with cholesterol. Numerous studies have indicated that the cholesterol efflux induced by apoA-I-containing lipoproteins involves cell-surface receptor, caveolae and intracellular cholesterol mobilization. Therefore, we investigated these characteristics for the BSP-mediated cholesterol efflux. Binding of BSP proteins to cells (evaluated by immunoblotting) reached saturation rapidly and remained constant thereafter. However, after several washings the cell-bound BSP proteins were unable to promote significant cholesterol efflux. Both results indicate no correlation of cholesterol efflux with cell binding. Moreover, in comparison to apoA-I-mediated cholesterol efflux, BSP-mediated efflux was not abolished at temperatures below 22 degrees C indicating that the BSP-induced cholesterol efflux does not involve intracellular cholesterol mobilization. High-density lipoprotein- and apoA-I-mediated cholesterol efflux was inhibited by preincubating fibroblasts with progesterone, whereas the cholesterol efflux by BSP proteins was not, indicating that cell-surface caveolae do not participate in BSP-mediated cholesterol efflux. Our results indicate that the mechanism of cholesterol efflux by BSP proteins is unidirectional and is strikingly different from that mediated by apoA-I-containing lipoproteins.

Role of aortic nitric oxide synthase 3 (eNOS) in the systemic vasodilation of portal hypertension

BACKGROUND & AIMS

In portal hypertension, the mechanisms responsible for nitric oxide (NO) overproduction and vasodilation have not yet been clearly identified. One hypothesis is that NO synthase (NOS) 3 is overactivated because of shear stress in endothelial cells caused by hyperkinetic circulation. The aim of this study was to evaluate aortic NOS3 after a reduction of blood flow by long-time beta-adrenoceptor antagonist administration.

METHODS

Propranolol or atenolol was administered by gavage in portal vein-stenosed and sham-operated rats. The vascular reactivity of thoracic aortic rings to phenylephrine, total aortic NOS activity, and aortic NOS3 messenger RNA and protein expressions were studied.

RESULTS

After propranolol or atenolol administration, the aortic hyporesponse returned to normal in portal vein-stenosed rats. Total aortic NOS activity was higher in portal vein-stenosed aortas and significantly decreased after beta-blocker administration. Aortic NOS3 expressions were more marked in portal vein-stenosed aortas than in controls, but NOS3 expressions were reduced after propranolol administration.

CONCLUSIONS

In portal hypertension, aortic NOS3 activity and expressions are enhanced but return to normal after beta-blocker administration. These results suggest that in portal hypertension, increased shear stress, related to high blood flow, induces enhanced aortic NOS3.

Changes in protein kinase C isoforms in association with vascular hyporeactivity in cirrhotic rat aortas

BACKGROUND & AIMS

Although protein kinase C (PKC) alterations may play a role in the abnormal reactivity of cirrhotic rat aortas, its isoforms and cellular distribution are unknown. We therefore studied the protein expression and cellular distribution of PKC isoforms and their activation in cirrhotic rat aortas.

METHODS

Endothelium-denuded aortas from control and cirrhotic rats were examined. Immunoblots were performed with PKC isoform-specific antibodies. Aortic reactivity was determined for phorbol myristate acetate and phenylephrine after PKC down-regulation.

RESULTS

PKC-alpha expression was reduced in both the cytosolic and membrane fractions in cirrhotic aortas. Trace amounts of PKC-beta were detected in cirrhotic aortas. PKC-delta was detected in the cytosolic fraction of control and cirrhotic aortas. PKC-zeta was detected in the membrane fraction in control aortas and in the cytosolic fraction in cirrhotic aortas. Phorbol myristate acetate and phenylephrine triggered translocation of PKC-alpha and PKC-delta isoforms from the cytosol to the membrane in control aortas; in cirrhotic aortas, only PKC-alpha was translocated. Aortic reactivities were reduced after PKC down-regulation. PKC-alpha and -delta activities were reduced in cirrhotic aortas.

CONCLUSIONS

These results suggest that a change in PKC isoforms may be responsible in part for the abnormal reactivity and intracellular transduction through the PKC pathway in cirrhotic rat aortas.

The role of nitric oxide in the reduction of protein kinase C-induced contractile response in aortae from rats with portal hypertension

BACKGROUND/AIMS

Protein kinase C plays a role in the regulation of vascular cell contraction but its activity may be reduced by nitric oxide. In portal hypertension, the exact mechanism by which nitric oxide induces vascular hyporeactivity to vasoconstrictors is unclear. The aim of this study was to investigate the role of the interaction of nitric oxide and protein kinase C in the vascular reactivity in isolated aortae from portal vein-stenosed rats.

METHODS/RESULTS

The contractile response to phorbol 12,13-dibutyrate, a protein kinase C activator, was significantly reduced in portal vein-stenosed aortae compared to sham-operated aortae. Preincubation with N-nitro-L-arginine or endothelium removal enhanced the response to phorbol 12,13-dibutyrate. The hyporesponsiveness to phorbol 12,13-dibutyrate in portal vein-stenosed rat aortae was only corrected after endothelium removal. The time course of contractions induced by phorbol 12,13-dibutyrate showed that the contraction was maintained for 2 h in sham-operated aortae and decreased to baseline in portal vein-stenosed rat aortae. This decrease was inhibited by N-nitro-L-arginine preincubation or endothelium removal. Protein kinase C downregulation caused a more marked reduction of phenylephrine-induced contraction in portal vein-stenosed aortae than in sham-operated aortae. The time course of total nitric oxide synthase activity in the presence of phorbol 12,13-dibutyrate showed a decrease in nitric oxide synthase activity after 30 min in both groups. Nitric oxide synthase activity remained stable for 120 min in sham-operated aortae but returned to basal level in portal vein-stenosed aortae.

CONCLUSIONS

Hyporeactivity to vasoconstrictors in portal vein-stenosed rat aortae may be due, in part, to a decrease in protein kinase C activation caused by nitric oxide overproduction.

Economic impact of febrile morbidity and use of permethrin-impregnated bed nets in a malarious area II. Determinants of febrile episodes and the cost of their treatment and malaria prevention

The objective of this study is to determine the effect of permethrin insecticide-treated bed net (PITN) use on the incidence of febrile episodes and on household malaria expenses in Benin. Over the course of one year, 208 randomly selected PITN user and non-user households were visited weekly to determine expenditures on febrile morbidity and its treatment, and to monitor spending on malaria prevention. Multivariate analyses were performed to distinguish the effects of PITN use from other important determinants of morbidity, such as malaria-related beliefs and practices, income, and other socio-economic variables. Results from the logistic regression analysis show that the use of PITNs decreases the risk of febrile episodes by 34% in children living in the rural zone. Multiple regression analysis reveals that PITN use does not reduce prevention and treatment expenses. These expenses are significantly associated with women's income. This report also discusses other factors associated with febrile morbidity and malaria-related expenditures.

Haemodynamic responses to a ring-deleted analogue of atrial natriuretic peptide in rats with cirrhosis

AIMS

In cirrhosis, the effects of selective activation of atrial natriuretic peptide (ANP) R2-receptors on haemodynamics, endogenous ANP (ANP1-28) and sodium excretion are unknown. The aim of the present study was to examine the effects of selective activation of ANP-R2 receptors by ANP4-23 (a ring-deleted analogue of endogenous ANP) on haemodynamics, plasma ANP1-28 concentrations and urinary sodium excretion in conscious cirrhotic and normal rats.

METHODS

Haemodynamics and sodium excretion were measured prior to and following administration of ANP4 23. Plasma ANP1-28 concentrations were also measured.

RESULTS

In cirrhotic rats, ANP4-23 significantly decreased portal pressure and tributary blood flow by 15% and 25% respectively but significantly increased portal territory vascular resistance by 30%. Systemic and renal haemodynamics were not altered by ANP4-23. In normal rats, ANP4-23 did not significantly change splanchnic, renal and systemic haemodynamics. In both groups of rats, ANP4-23 increased plasma ANP1-28 concentrations but did not change sodium excretion.

CONCLUSIONS

ANP4-23 administration induced splanchnic vasoconstriction in cirrhotic but not in normal rats. ANP4-23-elicited vasoconstriction caused a portal hypotensive effect in cirrhotic rats. Finally, in both groups, ANP4-23 caused an increase in plasma ANP1-28 concentrations but did not increase sodium excretion.

Economic impact of febrile morbidity and use of permethrin-impregnated bed-nets in a malarious area I. Study of demographics, morbidity, and household expenditures associated with febrile morbidity in the Republic of Benin

In preparation for a study on the effect of bed net use on malaria, this article describes febrile morbidity and malaria expenditures in a sub-Saharan area (Benin) of hyperendemic malaria. The 325 randomly selected households were visited weekly between April 1994 and March 1995 to determine febrile morbidity and household expenditures for prevention and treatment. The results indicate that rural children had two febrile episodes annually compared with 0.3 episodes among children living in the city. There was no difference in mean annual febrile episodes between adults and children (adults = 1.5, children = 1.5; P = 0.48) and in the expenditures per febrile episode (adults = US$1.85, children = US$1.62; P = 0.45). Annual prevention expenditures were higher for adults than for children (US$1.73 and US$1.28, respectively; P < 0.001), although there was no significant difference in expenditures for annual treatment for adults and children (US$2.15 and US$2.34, respectively). These and other findings are analyzed further and discussed.

Aquaretic effects of niravoline, a kappa-opioid agonist, in patients with cirrhosis

BACKGROUND/AIMS

In patients with cirrhosis, decreased renal water excretion is a common complication. Niravoline (RU51599), a kappa-opioid receptor agonist, has been shown to induce an aquaretic response. The aim of this study was to evaluate the aquaretic effect and tolerance of niravoline in patients with cirrhosis.

METHODS

Biochemical tests and hemodynamic values were determined before and 1, 2, 3 and 24 h after niravoline administration at doses ranging from 0.5 to 2 mg iv in 18 patients with cirrhosis.

RESULTS

Diuresis significantly increased in the first hour from 64+/-9 to 146+/-31 ml/h, and returned to basal values after 3 h. Free water clearance also significantly increased, reaching the positive range at 1 h. Plasma osmolality significantly decreased at 2 h (from 290+/-4 to 286+/-4 mOsm/kg). Plasma sodium concentrations increased significantly at 3 h (from 133+/-1 to 134+/-1 mEq/l). Heart rate and arterial pressure did not change. The highest doses (1.5 mg or 2 mg) induced personality disorders and mild confusion within 2 h. These effects reversed completely within 8 h.

CONCLUSION

This study shows that niravoline administration induces an aquaretic response and is well tolerated, at moderate doses, in patients with cirrhosis. Thus, moderate doses of niravoline may be useful for treating patients with cirrhosis and water retention.

Determinants of the Permethrin Impregnated Bednets (PIB) in the Republic of Benin: the role of women in the acquisition and utilization of PIBs

An important aspect of malaria control strategies has been the use of prophylactic measures such as impregnated bednets; however, adoption of this strategy has been slow and uneven. This study considers the factors determining Permethrin Impregnated Bednets (PIB) use in the context of a PIB promotion project in a rural area of Benin undertaken between 1992 and 1995. Quantitative data, on socio-demographic characteristics, malaria knowledge, attitudes, and practices, were gathered from 191 households of PIB users and non-users for comparative purposes using a questionnaire format. Qualitative data were collected from 23 focus group discussion sessions and 16 semi structured interviews. Women's income, men's educational level, and women's participation in communal organizations were the principal variables distinguishing user households from non-user households. Recourse to non-western medicine and, in particular, to medicinal teas which are considered preventive or curative correlates negatively with PIB use. The qualitative data shows that informants consider exposure to the sun, especially while engaged in agriculture work, a principal cause of malaria, and that PIB adoption is not considered justified in a context where there is a quasi chronic shortage of financial resources and where confidence in the efficacy of non-western medicine prevails. Because they have primary responsibility for the health of their families and are more aware of children's vulnerability to malaria, women are more inclined than men to want to buy PIBs. However, because the household head, who is most often male, sets family consumption priorities using family income, women often have to resort to using their own income, which is often considerably lower than that of men, to buy PIBs. Support for community initiatives which are directed to women's work, linked with intensive effort to sensitize men to the mechanisms of malaria transmission and the principal groups at risk, is seen as a means to increase PIB acquisition and use.

Relationship between vascular reactivity in vitro and blood flows in rats with cirrhosis

In cirrhosis there is a hyperdynamic circulation, which occurs mainly in the systemic and splanchnic regions. Using isolated-vessel models, previous studies have shown reduced aortic reactivity to vasoconstrictors in rats with cirrhosis. The aim of the present study was to evaluate and compare the vascular responsiveness to phenylephrine in arterial rings and the blood flows from different regions in rats with cirrhosis and controls. Reactivity was studied in isolated thoracic aortic, superior mesenteric arterial and carotid arterial rings from sham-operated and bile-duct-ligated rats by measuring the cumulative concentration-dependent tension induced by phenylephrine (10(-9)-10(-4) M). Blood flows were measured by the radioactive microsphere method. In rats with cirrhosis, a significant hyporeactivity to phenylephrine was observed in both the aorta and the superior mesenteric artery compared with the corresponding arteries of normal rats. This hyporesponsiveness was corrected by N(omega)-nitro-L-arginine (0.1 mM). In contrast, carotid artery reactivity and the responses to N(omega)-nitro-L-arginine were similar in the cirrhotic and control groups. In each case, cardiac output and mesenteric arterial blood flow were significantly higher in cirrhotic than in normal rats. Cerebral blood flows were not significantly different between the two groups. In cirrhotic rats, arterial hyporeactivity may be a consequence of increased regional blood flow and increased production of nitric oxide.

Bovine seminal plasma phospholipid-binding proteins stimulate phospholipid efflux from epididymal sperm

Several studies have shown that sperm capacitation was accompanied by a change in the lipid composition of the sperm membrane. In cattle, the major proteins of (bovine)seminal plasma (BSP proteins: BSP-A1/A2, BSP-A3, and BSP-30-kDa) potentiate sperm capacitation induced by high-density lipoprotein (HDL). Our recent studies indicate that these proteins and HDL stimulate sperm cholesterol efflux during capacitation. In order to gain more insight into the mechanisms of BSP-mediated sperm capacitation, we studied whether or not BSP proteins induce phospholipid efflux from epididymal sperm membrane. By direct determination of choline phospholipids on unlabeled epididymal sperm, the results show that sperm incubated in the presence of BSP-A1/A2 protein lost 34.4% of their choline phospholipids compared with the control (11.5%). Similar results were obtained using labeled epididymal sperm. Labeling was carried out by incubating washed epididymal sperm for 1 h with medium containing [(3)H]palmitic acid. The majority of the label was incorporated into sperm phosphatidylcholine. Studies of sperm phospholipid efflux were done by incubating the labeled sperm with purified BSP proteins, delipidated BSA, or bovine seminal ribonuclease (RNase, control protein). When labeled ([(3)H]phospholipid) epididymal sperm were incubated with BSP proteins (20-120 microg/ml) for 8 h, the sperm lost [(3)H]phospholipid in a dose-dependent manner (maximum efflux of approximately 30%). After the incubation with BSP proteins, the efflux particles were fractionated by size-exclusion chromatography. Analysis of the fractions obtained showed that the [(3)H]phospholipid was associated with BSP proteins. BSA (6 mg/ml) stimulated a specific phospholipid efflux of approximately 22%. In contrast, bovine RNase (120 microg/ml) did not stimulate phospholipid efflux. These results indicate that BSP proteins participate in the sperm cholesterol and phospholipid efflux that occurs during capacitation.

Abnormal regulation of aortic NOS2 and NOS3 activity and expression from portal vein-stenosed rats after lipopolysaccharide administration

Hyporeactivity to vasoconstrictors in aortae from portal vein-stenosed rats is associated with an increased activity of endothelial NO synthase (NOS3). In contrast, during sepsis, which is common in cirrhosis, vascular hyporeactivity is associated with an induction of inducible NOS2. The aim of this study was to investigate the in vitro reactivity to phenylephrine and the regulation of NOS2 and NOS3 in aortae from portal vein-stenosed rats after lipopolysaccharide (LPS) administration. Aortic vascular reactivity for phenylephrine, aortic NOS activity, and NOS2 and NOS3 protein expression were determined 5 hours after intravenous LPS or saline administration. Moreover, aortic NOS activity was measured after 5-hour in vitro incubation in LPS. LPS induced a significantly smaller decrease in aortic tension in portal vein-stenosed than in sham-operated rats. Under baseline conditions, aortic NOS activity and NOS3 protein expression were higher in portal vein-stenosed than in sham-operated rats, and NOS2 protein expression was not detected in aortae from either group. After LPS administration, NOS activity and NOS2 protein expression increased significantly less in portal vein-stenosed than in sham-operated rat aortae. Similar results were obtained after in vitro incubation with LPS. Endothelium removal or NOS3 inhibition with the calmodulin inhibitor, W7, increased NOS activity in the aortae of portal vein-stenosed rats after LPS incubation. In conclusion, in aortae of portal vein-stenosed rats exposed to LPS, no further decrease in aortic reactivity to phenylephrine was observed, and the induction of NOS2 was down-regulated. Endothelium removal or calmodulin inhibition inhibits NOS3 overactivity and leads to normalized NOS2 activation after LPS in aortae from portal vein-stenosed rats.

Relation between severity of liver disease and renal oxygen consumption in patients with cirrhosis

BACKGROUND

Worsening cirrhosis may lead to increased renal O2 metabolism caused by activation of neurohumoral antinatriuretic substances.

AIMS

To evaluate the relation between the severity of liver disease, sodium excretion, and neurohumoral antinatriuretic substances on the one hand and renal O2 metabolism on the other in patients with cirrhosis.

METHODS

Renal O2 consumption and haemodynamics as well as plasma concentrations of noradrenaline, renin, and aldosterone were measured. Investigations were performed in 14 patients with Pugh's grade A, 43 with grade B, and 29 with grade C liver disease.

RESULTS

Renal O2 consumption significantly increased with the severity of cirrhosis (grade A, 8.9 (1.6); grade B, 15.5 (1.3); grade C, 18.0 (1.5) ml/min/m2). Plasma concentrations of noradrenaline, renin, and aldosterone significantly increased while mean arterial presssure and systemic vascular resistance significantly decreased with the severity of the disease. A significant inverse correlation was found between renal O2 consumption and sodium excretion. A significant direct correlation was found between plasma levels of noradrenaline and aldosterone on the one hand and renal O2 consumption on the other. Renal blood flow and the glomerular filtration rate did not differ significantly between patients with grade C and grade A or B disease.

CONCLUSIONS

This study shows for the first time that, in patients with cirrhosis, worsening of the disease is associated with an increase in renal O2 consumption. The results suggest that increased renal O2 consumption is due to renal tubular sodium retention caused by increased levels of neurohumoral antinatriuretic substances. This neurohumoral activation is related to cirrhosis induced vasodilation.

Characterization of lipid efflux particles generated by seminal phospholipid-binding proteins

We reported recently that the choline phospholipid-binding proteins (BSP-A1/-A2, BSP-A3 and BSP-30-kDa) of bovine seminal plasma (BSP) stimulate cholesterol and choline phospholipid efflux from fibroblasts. In this study, we characterized the lipid efflux particles generated by BSP proteins. The density gradient ultracentrifugation of the efflux medium from radiolabeled fibroblasts incubated with BSP proteins showed a single peak of [3H]cholesterol between density (d) 1.12 and 1.14 g/ml, which is in the range of high-density lipoproteins. Size-exclusion chromatographic and immunoblot analysis revealed that the efflux particles have a large size equal to or bigger than very low-density lipoproteins and contained BSP proteins. Lipid analysis of density gradient and gel filtration fractions from efflux medium of simultaneously labeled fibroblasts ([3H]cholesterol and [3H]choline) incubated with BSP proteins showed that the efflux particles were homogeneous and composed of cholesterol and choline phospholipids. The lipid particles contained BSP proteins, cholesterol and choline phospholipids in molar ratio of 0.05:1.21:1, respectively. Agarose gel electrophoresis showed that the BSP-generated lipid particles had a gamma migration pattern which is slower than low-density lipoproteins. The sonication of cholesterol and BSP proteins followed by gel filtration chromatographic analysis indicated no direct binding of cholesterol to BSP proteins. These results taken together indicate that BSP proteins induce a concomitant cholesterol and choline phospholipid efflux and generate large protein-lipid particles.