Marked liver tumorigenesis by Helicobacter hepaticus requires perinatal exposure.

BACKGROUND: Although severe hepatitis and liver tumors occur in a high percentage of A/J male mice naturally infected with Helicobacter hepaticus, these effects have not been observed after injection of adult mice with the bacteria. OBJECTIVES: We tested the hypothesis that perinatal exposure to the bacteria is required for liver tumorigenesis. METHODS: A/J female mice were infected by intragastric (ig) or intraperitoneal (ip) treatment with 1.5 x 10(8) H. hepaticus before pregnancy. We examined offspring at progressive time intervals, including some kept until natural death in old age. A/J, BALB/c, and C57BL/6 weanling male mice were similarly treated ig with the bacteria and observed for up to 2 years. RESULTS: After ip bacterial infection of A/J females, 41% of their male offspring developed hepatitis and 33% had hepatocellular tumors, including 18% with hepatocellular carcinoma. Treatment by the ig route resulted in a similar incidence of hepatitis in offspring (35%) but fewer total liver tumors (8%) and carcinomas (4%). By contrast, ig instillation of H. hepaticus in weanling A/J, C57BL/6, or BALB/c mice resulted in low incidence of hepatitis (0-20%) and few liver tumors, despite presence of bacteria confirmed in feces. CONCLUSIONS: Results indicate that a high incidence of liver tumors in mice infected with H. hepaticus requires perinatal exposure. Contributing perinatal factors could include known high sensitivity of neonatal liver to tumor initiation, and/or modulation of immune response to the bacterium or its toxins. Mechanisms of human perinatal sensitivity to such phenomena can be studied with this model.

Cu(II) complexation does not affect oxytocin action on pregnant human myometrium in vitro.

OBJECTIVE: Copper may influence the in vivo and in vitro uterine activity. Recent evidence shows that cupric ions can easily form complexes with oligopeptides like oxytocin (OXT). The high complex stability in vitro suggests a possibility of complex formation in vivo. STUDY DESIGN: In vitro isometric contractions were recorded in uterine tissues from pregnant women undergoing caesarean sections and the effect of OXT and the Cu-OXT complex on isolated human pregnant myometrium was investigated. RESULTS: In the concentration range from 10(-14) to 10(-6)M of OXT alone, pre-formed Cu-OXT complex, and OXT following sample preincubation with Cu(II) salt, nosignificant differences were observed for the following parameters of pregnant uterine smooth muscle contraction: the area under the curve, frequency and amplitude of contraction. CONCLUSION: The binding of Cu(2+) ions does not abolish the ability of OXT to interact with oxytocin receptors and stimulate myometrial contraction in vitro.

Apamin inhibits NO-induced relaxation of the spontaneous contractile activity of the myometrium from non-pregnant women.

There is now considerable evidence for the involvement of K+ channels in nitric oxide (NO) induced relaxation of smooth muscles including the myometrium. In order to assess whether apamin-sensitive K+ channels play a role in NO - induced relaxation of the human uterus, we have studied the effect of specific blockers of these channels on the relaxation of myometrium from non-pregnant women. In vitro isometric contractions were recorded in uterine tissues from non-pregnant premenopausal women who had undergone hysterectomy. Apamin (10 nM) and scyllatoxin (10 nM) did not alter spontaneous myometrial contractions. However, 15-min pretreatment of the myometrium strips with apamin completely inhibited relaxation caused by diethylamine-nitric oxide (DEA/NO). The pretreatment with scyllatoxin significantly reduced (about 2.6 times) maximum relaxation of the strips induced by DEA/NO (p < 0.05). These results strongly suggest that, beside Ca2+ and voltage dependent charybdotoxin-sensitive (CTX-sensitive) K+ channels, apamin-sensitive K+ channels are also present in the human non-pregnant myometrium. These channels offer an additional target in the development of new tocolytic agents.

[Smoking in pregnancy--long term effect]. / Palenie tytoniu w ciazy--efekty odlegle.

OBJECTIVES: The data review on the cancer risk in children exposed to tobacco smoke in utero. MATERIALS AND METHODS: The analysis was based on databases available in Medline, Cancerlit and Cochrane. RESULTS: The reviewed data confirm that the risk of developing malignancy after the exposure to maternal smoking is low. Nevertheless, some publications point to a higher risk of having brain tumors or leukemias. CONCLUSIONS: Together with facts that fetus is jeopardized with toxic metabolites of tobacco smoke which cause genotoxic effects or DNA adducts give additional arguments the necessity of introducing smoking cessation programs in perinatal care.