Hepatitis A infection in patients with chronic viral liver disease: a cross-sectional study in Jahrom, Iran.

Infection with hepatitis A virus (HAV) in patient with chronic liver disease (CLD; due to hepatitis B or hepatitis C) may cause severe disease and fulminant liver failure. This study aimed to determine the seroprevalence of HAV antibodies in patients infected with HCV or HBV in Iran (Jahrom city). A total of 159 patients with underlying CLD were recruited between September 2012 and February 2013. Serum samples were collected from each patient and tested for anti-HAV using enzyme-linked immunosorbent assay (ELISA). The overall seroprevalence of total anti-HAV was 79·2%. Patients aged 20-30 years had the lowest (28·3%) anti-HAV seropositivity and those aged >50 years had the highest (95%) seropositivity. The overall prevalence of anti-HAV in patients with chronic HCV and HBV infection was 93·7% and 77·1%, respectively. The anti-HAV seropositivity in liver cirrhosis patients was 100% compared to CLD patients. Because of low HAV immunity in younger CLD patients, vaccination against HAV should be considered.

Presence of nitrotyrosine with minimal inducible nitric oxide synthase induction in lipopolysaccharide-treated pigs.

The production of large amounts of nitric oxide (NO) by the inducible form of nitric oxide synthase (iNOS) and the subsequent production of peroxynitrite (OONO-) are believed to be major factors in the hemodynamic abnormalities of sepsis. This finding is based on data from rats and mice but has not been established in other species. Therefore, we examined the role of iNOS in lipopolysaccharide (LPS)-treated pigs, which have a hemodynamic pattern with sepsis that is more similar to humans than rats. Pigs were anesthetized, ventilated, and given LPS (n = 12), 20 microg/kg over 2 h, or saline (n = 7). They were killed after 2 (n = 8 LPS, 7 control) or 4 h (4 LPS). We measured cardiac output (CO), mean arterial (Part), and pulmonary and central venous pressures. We evaluated NO production by measuring expired NO, and plasma nitrate/nitrite concentration, NOS activity (in lung tissue), and iNOS protein by Western analysis, and immunohistochemistry (lung and liver), as well as iNOS mRNA by Northern analysis (liver and lung). We also measured nitrotyrosine as evidence of OONO- production by slot blot, Western analysis, and immunohistochemistry. By 2 h, Part fell and CO did not change so that systemic vascular resistance decreased from 21.5+/-2.9 to 12.7+/-3.1 mmHg x L(-1) x min (P < 0.05) and remained at 11.3+/-1.7 mmHg x L(-1) x min in the animals observed for 4 h. Plasma nitrate/nitrite, expired NO, and NOS activity did not change. We found no iNOS in tissues by Western analysis with 5 different antibodies but detected a small amount of iNOS by immunohistochemistry in inflammatory cells and small vessels. There was a small increase in iNOS mRNA in liver and lung. Despite the minimal increase in iNOS, nitrotyrosine was increased in small vessels and in inflammatory cells. In conclusion, caution should be used when extrapolating the septic response in rodents to other species, for the pattern of iNOS induction is very different.

Regional distribution of endothelin-1 and endothelin converting enzyme-1 in porcine endotoxemia.

Endothelin-1 (ET-1) levels are markedly increased in sepsis. Since ET-1 is primarily transcriptionally regulated, there should be a corresponding increase in pre-pro-endothelin-1 (ppET-1). Our objective was to determine whether ppET-1 is increased in pigs with a low systemic vascular resistance. We also examined the distribution of ET-1 and the regulation of endothelin-converting enzyme 1 (ECE-1), the rate limiting enzyme in ET-1 production. We anesthetized and ventilated 16 pigs. We measured arterial, pulmonary, and central venous pressures, as well as cardiac output. ET-1 was measured by radioimmunoassay in plasma and in multiple tissues. We infused 20 microg/kg of endotoxin over 2 h and then sacrificed the animals. ppET-1 and ECE-1 mRNA were assessed by Northern analysis. We performed immunohistochemistry for the assessment of tissue ET-1 and ECE-1. The systemic vascular resistance rose at 30 min, but fell by 120 min. Plasma ET-1 more than doubled by 2 h. However, there was no change in the concentration of ET-1 in any tissue except in the pulmonary artery. By immunohistochemistry, there was also no change in ET-1 in aorta, vena cava, heart, lung, liver, and kidney. Distribution of ECE-1 followed that of ET-1 on immunohistochemistry. There was a significant increase in ppET-1 mRNA in liver, kidney papillae, and vena cava, and a tendency for an increase in other tissues. This was paralleled by an increase in ECE-1 mRNA. In conclusion, the amount of ECE-1 mRNA and protein parallel those of ET-1. Endotoxemia is associated with a marked increase in plasma ET-1 and an increase in ppET-1 and ECE-1 mRNA in multiple tissues; however, there was no significant change in tissue ET-1 except in the pulmonary artery. The rise in plasma levels without a change in tissue levels suggests a greater release into the vasculature in sepsis than under normal conditions.

Regional changes in constitutive nitric oxide synthase and the hemodynamic consequences of its inhibition in lipopolysaccharide-treated pigs.

The role of constitutive nitric oxide synthases (cNOS) in sepsis remains controversial. Part of the problem is that many of the studies have been performed in rats, which respond differently than larger animals. Our objective, therefore, was to determine whether cNOS, i.e. ecNOS (NOS-3) and nNOS (NOS-1) are still active in vessels of pigs treated with lipopolysaccharide (LPS) from Escherichia coli. We also characterized the dose-response relationship of the NOS inhibitor N(G)-nitro-L-arginine-methyl-ester (L-NAME) in the arterial, venous, and pulmonary circuits as a reflection of NO production. We anesthetized and ventilated 14 pigs, which were instrumented for hemodynamic measurements. We measured mean circulatory filling pressure and resistance to venous return by transiently arresting the circulation with a balloon in the right atrium. Animals were given 20 microg/kg of LPS (n = 8) or saline (n = 6) over 2 h. They were then given progressively increasing doses of L-NAME (0.5 to 16 microg/kg). We injected 20 microg boluses of norepinephrine at baseline, after 2 h, and after 0.5, 4, and 16 microg of L-NAME to test the pressor response. Tissue was obtained from six control animals followed for 2 h, eight animals treated with LPS for 2 h and then sacrificed, and four animals treated for 2 h and sacrificed after 2 more h. Cardiac output did not change, and the systemic vascular resistance fell in LPS animals. By Western analysis, ecNOS was increased in LPS animals at 2 and 4 h in the aorta and vena cava, and this was paralleled by changes in nNOS in the vena cava. In contrast, ecNOS decreased in the pulmonary artery and nNOS did not change. Calcium-dependent NOS activity increased with LPS in the aorta and vena cava but decreased in pulmonary artery at 4 h. The dose-response relationships to L-NAME for systemic vascular resistance, resistance to venous return, and cardiac output were shifted to the left after LPS in support of increased sensitivity supporting increased NO. The pressor response to norepinephrine was depressed after LPS and was partially restored with 4 mg/kg of L-NAME, but this dose produced 90% of the fall in cardiac output. In conclusion, in contrast to rats, cNOS activity is present in the systemic vessels of LPS-treated pigs and could play a role in the pathophysiology of sepsis.

Intercellular communication between Sertoli cells and Leydig cells in the absence of follicle-stimulating hormone-receptor signaling.

Effective interactions among the various compartments of the testis are necessary to sustain efficiency of the spermatogenic process. To study the intercellular communication between the Sertoli and Leydig cells in the complete absence of FSH receptor signaling, we have examined several indices of Leydig cell function in FSH receptor knockout (FORKO) mice. The serum testosterone levels were reduced in the 3- to 4-mo-old adult FORKO males compared to wild-type mice despite no significant alteration in circulating LH levels. Treatment with ovine LH resulted in a dose-dependent increase in serum testosterone levels in all three genotypes (+/+, +/-, and -/-). However, the response in FORKO males was significantly reduced. Similarly, the total intratesticular testosterone per testis was also lower, but the intratesticular testosterone per milligram of testis was significantly elevated in the FORKO males. Western blot analysis revealed an apparent higher expression of the enzyme 3beta-hydroxysteroid dehydrogenase (3beta-HSD) as well as LH-receptor density in the testis of FORKO males. Immunohistochemistry also showed an increase in the intensity of 3beta-HSD staining in the testicular sections of FORKO males. Although LH receptor binding increased per unit weight in FORKO mice, the total LH binding remained the same in all genotypes. Taken together, the results of the present study suggest that, in the absence of FSH receptor signaling, the testicular milieu is altered to affect Leydig cell response to LH such that circulating testosterone is reduced in the adult mutant. Studies are currently under way to understand the mechanisms underlying this phenomenon.

Regulation of diaphragmatic nitric oxide synthase expression during hypobaric hypoxia.

Nitric oxide (NO) is normally synthesized inside skeletal muscle fibers by both endothelial (eNOS) and neuronal (nNOS) nitric oxide synthases. In this study, we evaluated the influence of hypobaric hypoxia on the expression of NOS isoforms, argininosuccinate synthetase (AS), argininosuccinate lyase (AL), and manganese superoxide dismutase (Mn SOD) in the ventilatory muscles. Rats were exposed to hypobaric hypoxia ( approximately 95 mmHg) from birth for 60 days or 9-11 mo. Age-matched control groups of rats also were examined. Sixty days of hypoxia elicited approximately two- and ninefold increases in diaphragmatic eNOS and nNOS protein expression (evaluated by immunoblotting), respectively, and about a 50% rise in diaphragmatic NOS activity. In contrast, NOS activity and the expression of these proteins declined significantly in response to 9 mo of hypoxia. Hypoxia elicited no significant alterations in AS, AL and Mn SOD protein expression. Moreover, the inducible NOS (iNOS) was not detected in normoxic and hypoxic diaphragmatic samples. We conclude that diaphragmatic NOS expression and activity undergo significant adaptations to hypobaric hypoxia and that iNOS does not participate in this response.

Renal effects of prolonged intrarenal infusions of angiotensin II and atrial natriuretic peptide in sheep.

Angiotensin II (AngII) and atrial natriuretic peptide (ANP) are two hormones that have antagonistic effects on volume and pressure regulation. Plasma levels of both hormones are elevated in sheep pregnancy. However, during pregnancy, volume expansion occurs despite elevated plasma ANP, implying an overriding role of AngII. In addition to counteracting the effects of ANP on the physiological level, AngII also may act on the receptor level. Therefore this study was designed to investigate the hemodynamic and renal effects of ANP and AngII separately and to define their selective effects on the renal natriuretic peptide receptor types in the various segments of the nephron. Eight unilaterally nephrectomized nonpregnant sheep received separately for 10 days, low doses of AngII (1 ng/kg/min) and ANP (0.5 ng/kg/min) directly infused into the renal arteries to avoid systemic effects. Intrarenal AngII infusion decreased sodium excretion (UNaV) from 111+/-11 to 36 +/-8 and 45+/-6 mmol/day (p<0.05) on days 3 and 8-10, respectively. Mean arterial pressure (MAP) increased from 94 +/-6 mm Hg to a maximum of 107+/-8 mm Hg on day 5 of infusion and stabilized at 101+/-7 mm Hg on days 8-10 (p<0.05). Intrarenal ANP infusion significantly increased UNaV on day 1 from 93+/-9 to 188+/-20 mmol/day (p<0.05), followed by sodium retention on days 4-6 (average, 60+/-13 mmol/day; p<0.05). UNaV again increased above control levels on days 8-10 to an average level of 111+/-15 mmol/day. MAP decreased from 99+/-4 to 90+/-5 mm Hg (p<0.05) on days 1-3, and remained lower than control throughout the infusion period. The kidneys were collected at control nephrectomy and at the end of infusion. The natriuretic peptide receptors were characterized by competitive-binding radioreceptor assays on glomerular, outer medullary, and inner medullary membranes. AngII infusion increased the dissociation constant (Kd) of inner medullary natriuretic peptide receptors from 186 +/-11 to 267+/-22 pM (p<0.05), and ANP infusion decreased maximal binding capacity (Bmax) of inner medullary receptors from 134+/-10 to 89+/-15 fmol/mg protein (p<0.05). Glomerular and outer medullary natriuretic peptide receptors were not affected by either AngII or ANP infusion. In conclusion, AngII stimulates antinatriuresis and counteracts the hemodynamic and renal effects of ANP in part by downregulating the renal inner medullary natriuretic peptide receptors.

Porcine endotoxemic shock is associated with increased expired nitric oxide.

OBJECTIVES: Nitric oxide (NO) is believed to decrease systemic vascular resistance in sepsis, but the data are mainly from studies on rats and mice. We tested this hypothesis in pigs and also whether there is induction of the inducible form of nitric oxide synthase (iNOS). DESIGN: Animal study. SETTING: University center. SUBJECTS: Ten pigs. INTERVENTIONS: The pigs were anesthetized and mechanically ventilated. MEASUREMENTS AND MAIN RESULTS: Pulmonary and systemic hemodynamics were monitored and mixed expired NO was measured by chemiluminescence. Animals received 20 microg/kg of endotoxin over 2 hrs. We then infused 25 mg/kg of N(omega)-nitro-L-arginine methyl ester (L-NAME) over 10 mins, followed by 0.5 g/kg of L-arginine, the precursor of NO, for 30 mins more to reverse the effects of L-NAME. Five additional pigs were treated with 20 microg/kg of endotoxin for 2 hrs and followed for another hour. Plasma nitrite/nitrate was measured by Greiss reaction. The animals were then killed and tissues were sampled for iNOS by Western blot, and iNOS messenger RNA by reverse transcriptase polymerase chain reaction. After endotoxin infusion, arterial pressure (BP) initially increased, then decreased to 62+/-1 mm Hg from the baseline of 115+/-4 mm Hg (p<.001). Cardiac output initially decreased, then increased slightly from the baseline of 3.7+/-0.2 to 4.2 +/-0.3 L/min (p<.05). The BP pattern was mirrored by an increase in expired NO concentration from 6.4+/-0.8 to 10.4+/-1.4 parts per billion (p<.05) and increased rate of pulmonary NO excretion in expired gas (VeNO) from 71+/-10 to 146+/-24 pmol/kg/min (p<.05). Inhibition of NOS with L-NAME decreased expired NO concentration and VeNO and increased BP; however, cardiac output decreased. The vasoconstriction produced by L-NAME was partially reversed by L-arginine, and this also increased VeNO from 80+/-18 after L-NAME to 132+/-31 pmol/kg/min (p<.05). Plasma nitrite (n = 5) did not change and there was no iNOS by Western blot analysis in multiple tissues. However, there was a small increase in messenger RNA by reverse transcriptase polymerase chain reaction. CONCLUSIONS: The time course and pattern of changes in expired NO during endotoxemia followed the change in systemic hemodynamics, which supports a causal role for NO in sepsis. However, this is not due to a large production of NO by iNOS induction. The hemodynamic pattern, nitrite in blood, and changes in expired NO also differed markedly from those findings in rodent models and caution should be used in extrapolating from rodents to higher order animals.

Control of atrial natriuretic factor by right and left atrial distension in pregnant sheep.

Previous studies of the atrial stretch-atrial natriuretic factor (ANF) relationship during pregnancy have employed volume expansion and measured only right atrial pressure (RAP). Consequently, we studied nonpregnant (n = 7) and 115- to 125-day pregnant (n = 7) sheep and assessed the ANF response to changes of RAP and left atrial pressure (LAP) induced by graded balloon inflation. Ewes prepared with vascular catheters and atrial balloons were studied after recovery from preparatory surgical procedures. The basal levels of mean arterial pressure (MAP, 83 +/- 3 mmHg), RAP (2.1 +/- 0.7 mmHg), LAP (4.7 +/- 0.9 mmHg), and heart rate (HR, 102 +/- 6 beats/min) were similar in nonpregnant and pregnant sheep. Pregnancy also resulted in elevation of ANF concentration from 25 +/- 6 to 57 +/- 4 fmol/ml. With right atrial distension, the RAP-ANF relationships were similar in both nonpregnant and pregnant sheep, with a 10-mmHg increase in RAP increasing ANF by an average of 95 +/- 9 fmol/ml. In nonpregnant sheep, the LAP-ANF relationship was more responsive than RAP-ANF because a 10-mmHg increase in LAP resulted in a 193 +/- 10 fmol/ml increase in ANF. Moreover, during pregnancy, the LAP-ANF relationship was significantly more sensitive because a 10-mmHg increase in LAP resulted in a 433 +/- 15 fmol/ml elevation of ANF. These data demonstrate that plasma ANF levels are more responsive to distension of the left atria than to the right. More importantly, the ANF response to left, but not right, atrial distension is enhanced by pregnancy.

Effects of angiotensin II on plasma atrial natriuretic factor in nonpregnant and pregnant ewes.

The release of atrial natriuretic factor (ANF) is primarily determined by atrial stretch, but may also be modulated by circulating angiotensin II (AngII). During pregnancy, the circulating concentrations of both ANF and AngII are increased. To further define possible effects of AngII on ANF release, four doses of AngII (0.5, 5, 20, 40 ng.kg-1.min-1) were intravenously infused into five nonpregnant and five pregnant (105-140 days of gestation) ewes alone and during the simultaneous infusion of sodium nitroprusside at doses sufficient to abolish the pressor effects of AngII. Mean arterial pressure (MAP) was increased from 80 +/- 2 to a maximum of 121 +/- 5 mmHg (1 mmHg = 133.3 Pa) in nonpregnant ewes (p < 0.01) and from 79 +/- 2 to 116 +/- 4 mmHg in pregnant ewes (p < 0.01) over the range of AngII infusion. MAP was unaltered during AngII plus nitroprusside infusion, averaging 78 +/- 3 mmHg in nonpregnant ewes and 80 +/- 2 mmHg in pregnant ewes. Basal ANF was higher (p < 0.01) in pregnant sheep than in nonpregnant sheep. With AngII infusion alone, plasma ANF was increased from 13 +/- 2 to 42 +/- 4 fmol/microL in nonpregnant ewes (p < 0.01) and from 23 +/- 5 to 72 +/- 16 fmol/microL in pregnant ewes (p < 0.01). However, during AngII plus nitroprusside infusion, the increases in plasma ANF observed were completely abolished in both nonpregnant and pregnant ewes.(ABSTRACT TRUNCATED AT 250 WORDS)