[Intestinal complications in twin-to-twin transfusion syndrome (TTTS) treated by laser coagulation (LC)]

AIM OF THE STUDY

The hemodynamic imbalance due to placental vascular anastomoses in TTTS but also vascular changes generated after intrauterine treatment may lead to hypoxic-ischemic complications. Different intestinal complications in TTTS are reviewed in this paper.

METHODS

Retrospective review of TTTS cases treated by laser coagulation (LC) from 2012-2015. Demographic data, fetal therapy, prenatal diagnosis (US, MRI) and perinatal outcome were recorded. We describe cases with intestinal complications and their postnatal management. Results are expressed by median and range.

RESULTS

29 monochorionic pregnancies with TTTS were treated (23 LC, 4 cord occlusions and 2 cord occlusions after LC). The diagnosis was made at 19 (16-26) weeks and 86% presented stage of Quintero ≥ II. In 70% of mothers survived at least one fetus with a median of 31 (24-37) weeks at birth. Four patients had intestinal complications (1 jejunal atresia, 2 ileal atresia, 1 perforated necrotizing enterocolitis), half of them had prenatal diagnosis. Postnatal resections of the affected segments and ostomies were performed. Intestinal transit was restored and there were no severe digestive sequelae after 21 (8-38) months of follow up.

CONCLUSIONS

Different types of intestinal complications were associated with TTTS and LC. US and MRI enable prenatal diagnosis of these complications and this allows prompt decisions after birth.

Etude de la dégradation de quelques composés organochlorés volatils par photolyse du peroxyde d'hydrogène en milieux aqueux

Le travail a eu pour but d'étudier l'efficacité de la photolyse du peroxyde d'hydrogène sur la dégradation de quelques composés organochlorés aliphatiques saturés (chiorométhanes et chloroéthanes) en milieu aqueux (pH 7,5). Les expériences ont été réalisées en réacteur statique, avec une Lampe basse pression à vapeur de mercure et avec des concentrations initiales en produit chloré de l'ordre de 10-6 mol l-1 et en H202 comprises entre 10-5 et 10-3 mol L-.

Les résultats montrent que le système H202/UV peut oxyder les composés organochlorés étudiés à l'exception des composés ne possédant pas d'atome d'hydrogène (CCL4 et C2 CL6). Les rendements d'oxydation obtenus avec Le réacteur utilisé dépendent du temps de réaction, de la concentration initiale en H202, du flux photonique et peuvent être nettement diminués par la présence de pièges à radicaux (ions bicarbonates) dans le milieu réactionnel.

Par ailleurs, une étude cinétique de la photolyse du peroxyde d'hydrogène en absence de matière organique est également présentée.

Ciprofibrate and triiodothyronine do not suppress in vivo induction of placental glutathione S-transferase expression in rat hepatocytes

Studies on hepatocyte primary cultures have suggested that loss of expression of the placental form of glutathione S-transferase in peroxisome proliferator (PP)-induced hepatocarcinogenesis is due to inhibition of glutathione S-transferase P (GSTP) transcription by the PPs. In the present study, we have analyzed the effect of a PP, ciprofibrate, and of another ligand of nuclear receptors, 3,3', 5-triiodo-L-thyronine (T3), on GSTP mRNA and protein levels in an in vivo model where GSTP expression was induced in Wistar rats by pre-treatment with a single dose of lead nitrate. Results indicate that administration of ciprofibrate or T3, immediately after lead nitrate treatment, did not exert any inhibitory effect on GSTP mRNA and protein levels, as revealed by both Western and immunohistochemical analysis. The results indicate that PPs do not inhibit hepatocyte GSTP expression induced in vivo by lead nitrate and suggest that inhibition of GSTP expression by PPs may not necessarily be the cause for the rapid disappearance of GSTP-positive preneoplastic lesions observed after a short term exposure to these agents.

Involvement of capsaicin-sensitive nerves in paraquat-induced mortality

Paraquat (PQ), a broad spectrum herbicide, produces severe lung inflammation and necrosis resulting in pulmonary fibrosis and respiratory failure. Tachykinins are peptides released by sensory C fibers and have the ability of influencing respiratory functions and cellular proliferation. To examine whether the damage caused by PQ involves tachykinins, rats were depleted in their content of tachykinins by systemic treatment with capsaicin prior to PQ exposure. The animal subjected to this treatment showed a 3-fold higher viability compared to those treated with PQ alone (75 vs 27%). Depletion of reduced glutathione (GSH) is associated with oxidative stress produced by reactive oxygen intermediates during PQ metabolism. This is considered to be critical in the pathogenesis of lung damage by PQ. PQ treatment induced a significant depletion of GSH during the first days and a similar effect was also observed in the group of capsaicin-pretreated rats. Four weeks after PQ treatment the levels of GSH were similar to controls in rat pretreated or not with capsaicin plus PQ. This may indicate that the reduced levels of GSH may be associated to the toxicity observed in the acute phase, but not of importance in the final PQ-induced mortality. Neutral endopeptidase (NEP) is an enzyme considered to be critical in controlling the levels of tachykinins. Exposure of crude membrane preparations of rat lung to PQ resulted in a dose-dependent inhibition of NEP activity. Since NEP inactivation may occur in lung following a PQ exposure in vivo, the results indicate that during PQ intoxication a more sustained activity of tachykinins may be present, producing effects such as cell proliferation, fluid extravasation and bronchoconstriction. In conclusion, this finding supports the hypothesis that neuropeptides released from capsaicin-sensitive nerves could be involved in the modulation of PQ-induced lung damage.

[Left vocal cord paralysis in cytomegalovirus multifocal neuropathy in a patient with HIV infection]

Cytomegalovirus multifocal neuropathies (CMV-MN) in patients with AIDS are much less frequent than meningoradiculitis. We report here the case of a patient with AIDS hospitalized because of severe motor weakness and paralyzed left true vocal cord (PVC), related to a multifocal neuropathy. CSF analysis was normal with a negative PCR for CMV, but neuromuscular biopsy showed typical CMV inclusions. The patient's condition improved with high dose foscarnet therapy, followed by a combination of ganciclovir plus foscarnet, during a five-month follow-up period. Twenty three case reports of CMV-MN have been published in the literature, only 2 of them presenting with a PVC. Extraneurological CMV involvement was usually documented. PCR for CMV in CSF was most often positive. However CMV inclusions were not frequently observed. The patients were usually improved under therapy with usually ganciclovir but relapse was observed in fifty percent within 3 to 6 months despite secondary prophylaxis.

Lipid peroxidation induced by N-acetylcysteine in isolated rat hepatocytes

In isolated rat hepatocytes N-acetylcysteine induces an increase of lipid peroxidation, as evaluated by the malondialdehyde production and diene conjugation. Lipid peroxidation did not result in increased cell mortality. Antioxidants and free radicals scavengers completely protect toward lipid peroxidation induced by N-acetylcysteine.

[In vitro conjugation of allyl alcohol and of its metabolites with reduced glutathione]

Hepatic GSH is utilized in conjugation reactions with the chemically-reactive metabolite, thus its measurement is a useful indication of the extent of conjugation. The toxic effect of allyl alcohol on rat livers is related to its conversion into acrolein. The toxicity of acrolein could be related to further metabolic activation into acrilic acid and/or glycidaldehyde. Allyl alcohol may also be converted into glycidol. Since hepatic GSH is an important determinant of allyl alcohol hepatotoxicity, we have studied "in vitro" reactivity of GSH with allyl alcohol, acrolein and glycidol. The addition of these chemicals to incubation mixtures containing liver 105.000 g supernatant fraction, phosphate buffer and GSH leads to GSH consumption, as measured by the Ellman's method. All the compounds examined react with GSH when added to incubation mixtures containing or no SPM. These results seem to indicate that these chemicals react with glutathione either enzymatically or no.

[Effect of phenobarbital on hepatic glutathione and GSH-S transferase in the rat]

In the livers of rats treated with phenobarbital an increase of glutathione-S-transferase and glutathione is observed. The results suggest that phenobarbital could alter the disposition of certain toxic not only by increasing the rate of formation of less toxic metabolites, but also by increasing the amount of glutathione available for GSH-S-transferase that is involved in the formation of less toxic glutathione conjugates.

[Reduced glutathione in rat liver intoxicated with allyl alcohol]

Within 24 h after administration of allyl alcohol the livers showed periportal necrosis and elevation of hepatic glutathione. After 48 h no necrosis was observed in spite of level of hepatic glutathione. The relationship between the hepatic glutathione and liver regeneration is discussed.

[Further investigations on the protective effect of cadmium acetate in bromotrichloromethane poisoning]

The rats were pretreated with cadmium acetate (20 mg/Kg.ip) and subsequently challenged with a dose of bromotrichloromethane (2,6 mmoles/Kg.po), the haloalkane produced no change on liver polyribosomes, as evidenced by disaggregation of sedimentation profile. Cadmium acetate failed to protect against CBrCl3-induced lipid peroxidation, as measured by malonaldehyde production of liver homogenate.

Bromobenzene hepatotoxicity in lead pretreated rats

We have studied the levels of hepatic GSH in animals intoxicated with bromobenzene. A marked decrease of hepatic GSH was observed in poisoned rats. Such decrease was prevented by previous administration of lead nitrate, an inhibitor of DMES. In the rats treated with lead nitrate alone a rise in hepatic GSH was observed. Such protection was further observed by histological examination. The mechanism of protection exerted by lead nitrate against bromobenzene intoxication is discussed.