Interleukin-6 Does Not Stimulate Rat Myometrial Contractions in an In Vitro Model

PROBLEM: Interleukin-6 (IL-6) is increased in culture-positive amniotic fluid in women with preterm labor. IL-6 stimulates the production of prostaglandins leading to increased uterine activity. METHODS: We tested the hypothesis that IL-6 increases myometrial activity through release of uterotonic mediators. We studied the effect of IL-6 on uterine contractions in the absence and presence of fetal membranes to determine if the effect was on myometrium alone or was mediated through fetal membranes/decidua. IL-6 in concentrations of 100, 10, 0.1 or 0 ng/ml was added to the maternal side of the dual chamber-fetal membrane-uterine muscle in vitro model. RESULTS: We found that 10 ng/ml of IL-6 alone, without fetal membranes, caused a significant decrease in uterine contractions over time (P≤0.01). This decrease was not observed with the addition of term, nonlabored fetal membranes. CONCLUSIONS: IL-6 in the presence or absence of membranes, over a four log fold dose range, did not stimulate uterine contractions.     

When should the hypoplastic right ventricle be used in a Fontan operation? An experimental and clinical correlation

Eight anesthetized dogs underwent closure of the tricuspid valve and a Fontan procedure, and the right ventricular cavity was reduced in stepwise fashion. There was an increase in right atrial pressure from 9.3 +/- 2.2 to 14.1 +/- 2.4 mm Hg (p less than 0.001), a decrease in pulmonary artery pulse pressure from 10.8 +/- 2.2 to 6.8 +/- 2.2 mm Hg (p less than 0.01), and a decrease in cardiac index from 2.7 +/- 0.3 to 2.2 +/- 0.2 L/min/m2 (p less than 0.001) when the ventricular size was dropped from 50% to 25% of normal. The difference between mean pulmonary artery pressure and mean right atrial pressure, which reflects the positive stroke work index of the ventricle, disappeared once the right ventricular cavity was reduced to 25% of normal (15.0 +/- 6.1 versus 14.1 +/- 2.4 mm Hg; p = not significant). Experimental results were correlated with postoperative catheterization data from 19 patients with tricuspid atresia who had the Fontan operation. Mean right atrial pressure was 18 +/- 4.6 mm Hg and cardiac index was 2.35 +/- 0.65 L/min/m2 in patients with a direct atrium-pulmonary artery anastomosis or an atrioventricular anastomosis with a right ventricular cavity less than 30% of normal versus 13 +/- 3.2 mm Hg and 3.42 +/- 0.46 L/min/m2 for those with an atrioventricular connection and a right ventricular cavity greater than 30% of normal (p less than 0.05 and p less than 0.02, respectively). The right ventricle enlarged from 27% +/- 6% of normal preoperatively to 35% +/- 10% of normal on follow-up (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)     

Neointimal Obstruction of Carpentier-Edwards Valved Conduit in Two Patients with Modified Fontan Procedure

In 2 patients (single ventricle and dextrotransposition of the great arteries with hypoplastic right ventricle) who underwent a modified Fontan procedure, significant disruption of the tricuspid patch developed. The valved conduits remained patent until reoperation at two and six months, respectively.At the time of reclosure of the tricuspid patch, unavoidable manipulation of the conduits from dissection of adhesions led to detachment and collapse of the neointima, thereby producing complete obstruction of the conduit. The problem was detected immediately in the first patient and prompted clearance of the conduit of the collapsed neointima. In the second patient, the diagnosis was made six months later and conduit replacement was required. Both patients did well following reoperation.We suggest that in patients with woven valved conduits inserted for a Fontan procedure who require reoperation and extensive manipulation of the conduit, removal of the neointima or conduit replacement should be considered.     

HLA class II influences humoral autoimmunity in patients with type 2 autoimmune hepatitis

BACKGROUND/AIMS: Type 2 autoimmune hepatitis (AIH) is characterized by the presence of anti-liver kidney microsome (anti-LKM-1) and/or anti-liver cytosol type 1 (anti-LC1) autoantibodies. However, the correlation between these autoantibodies and the genetic background has not been studied. METHODS: Frequencies of HLA class II alleles were compared between the 60 Caucasian children with type 2 AIH and 313 control subjects. The anti-LKM1 antibody reactivity directed against antigenic sites of CYP2D6 was analysed by ELISA. RESULTS: HLA-DQB1 *0201 allele was found to be the primary genetic determinant of susceptibility to type 2 AIH by conferring the highest odd-ratio (OR = 6.4). HLA-DRB1 *03 allele was significantly increased (P < 0.0001) among patients with both anti-LKM1 and anti-LC1 autoantibodies as well as in those with only anti-LC1(+) compared to those with anti-LKM1(+) alone. In contrast, HLA-DRB1 *07 allele was significantly associated (P < 0.0001) with anti-LKM1(+) alone compared to groups with both anti-LKM and anti-LC1 or with LC1+ alone. Children with the DRB1 *07 allele develop anti-LKM1 autoantibodies having a more restricted specificity (2 epitopes) than to those having HLA-DRB1 *03 allele (5 epitopes). CONCLUSIONS: The HLA-DR locus is involved in autoantibody expression, while the DQ locus appears to be a critical determinant for the development of type 2 AIH.