The pathophysiology of neurocardiogenic syncope remains incompletely known. In this entity, besides abnormal systemic hemodynamic regulation, potential cerebral circulatory abnormalities have been reported. In this setting, cerebral saturation assessment could detect cerebral blood flow changes and estimate the sufficiency of brain oxygenation during the event. A head-upright tilt test was performed in 25 children aged between 6 and 16 years. In addition to the standard protocol, cerebral oxygen saturation was determined noninvasively by means of a near-infrared spectrophotometry device. In the 19 children with a positive tilt test, significant impairment of cerebral saturation was detected both at the start of the patient's complaints (without hemodynamic modifications) and during syncope. Our results support the hypothesis of the presence of abnormal cerebral hemodynamic autoregulation in children with neurocardiogenic syncope.

Adolescent↗

PubMedDate not supplied

Limitations of percutaneous techniques in the treatment of portal vein thrombosis.

New therapeutic alternatives to portal vein thrombosis (PVT) include the percutaneous, transhepatic infusion of fibrinolytic agents, balloon dilatation, and stenting. These maneuvers have proven to be effective in some cases with acute, recent PVT. We have treated two patients with acute PVT via transhepatic or transjugular approaches and by using pharmacologic and mechanical thrombolysis and thrombectomy. Although both patients clinically improved, morphologic results were only fair and partial rethrombosis was observed. The limitations of percutaneous procedures in the recanalization of acute PVT in noncirrhotic patients are discussed.

Adult↗

PubMedDate not supplied

Studies on the interaction between antitrypanosome cis-DDP analogs with DNA.

The nature of the conformational changes produced in DNA by cis-DDP analogs has been studied by physiochemical techniques. The UV spectra showed that the DNA undergoes bathochromic shifts accompanied by hyperchromic effects in reaction with specific analogs (cis-Pt(DDH) (mucobromic)2, cis-Pt(tranilcypromine)2Cl2 and cis-Pt(DDH) Cl2), while a different series of analogs (cis-Pt(DDH) (metafluorobenzoic)2 and cis-Pt(pentamidine)Cl2) induce a significative decrease in the absorbance at 258 nm. Moreover one of these analogs (cis-Pt(pentamidine)Cl2) causes strong stabilization of the double helix to heat denaturation. The CD spectra indicate moreover that cis-Pt(pentamidine)Cl2 modifies the secondary structure of the DNA in a significant way with an increase of the positive band and a decrease of the ellipticity of the negative band. The antitrypanosome activity of cis-Pt(pentamidine)Cl2 is probably due to inhibition of the intracellular parasites division in parasitized cells.

Animals↗

PubMedDate not supplied

DNA interaction and antitumor activity of a Pt(III) derivative of 2-mercaptopyridine.

The complex [Pt2(Spy-)4Cl2], where Spy- is deprotonated 2-mercaptopyridine, was prepared and analyzed spectroscopically. A single signal in the 195Pt NMR spectrum indicates the equivalence of the two Pt(III) ions. The interaction of this complex with DNA was studied by circular dichroism and the modifications caused by the complex in plasmid pBR322 DNA were imaged by atomic force microscopy. Preliminary results showed higher activity against HeLa and U937 tumor lines for the Pt-2-mercaptopyridine complex in comparison with cisplatin. The values of LC50 were lower than those obtained for cisplatin. Promising perspectives for this compound are expected due to its similarity with the analogous Pt and 2-mercaptopyrimidine antitumor compound.

Antineoplastic Agents↗

PubMedDate not supplied

Toxicological characterisation of sludge from sewage treatment plants using toxicity identification evaluation protocols based on in vitro toxicity tests.

The ecotoxicological characterisation of complex mixtures, such as sludge from sewage treatment plants, is complex. Toxicity identification evaluation (TIE) protocols, developed by the United States Environmental Protection Agency (US EPA); to identify toxic pollutants in complex effluents, are useful tools in this context; to solve the difficulties in assessing unknown organic pollutants by analytical methods, the usefulness of bioassays to detect the relevant (toxic) organic compounds present in complex samples, and the possibilities of in vitro cytotoxicity tests as screening tools, offers a profitable combination. The sludge obtained from a sewage treatment plant was extracted by acetonitrile using a microwave extractor and fractionated in an HPLC system. The toxicity of every fraction was assayed using a RTG-2 cytotoxicty test, based on the fibroblastic RTG-2 fish cell line (ATCC, CCL N. 55). At exponential growth, three endpoints, beta-galactosidase activity, culture viability assayed by the neutral red assay (NR) and inhibition of growth rate using the FRAME KB protein assay (KBP), were used. By plotting the toxicity of each fraction vs elution time, the corresponding "toxicograms" were built. The UV and fluorescence chromatograms are compared to the three toxicograms (one for each toxicity endpoint).

Animal Testing Alternatives↗

PubMedDate not supplied

Adenovirus lacking the 19-kDa and 55-kDa E1B genes exerts a marked cytotoxic effect in human malignant cells.

UNLABELLED: The adenovirus (Ad) E1A gene exerts an antitumor effect and can induce sensitivity to treatment with DNA-damaging agents. In contrast, the Ad 19-kDa E1B protein inhibits E1A-mediated apoptosis and the 55-kDa E1B inactivates the p53 protein. In this paper, we study the in vitro and in vivo effects of a 19-kDa and 55-kDa E1B-defective Ad in several malignant human tumor cell lines. MATERIALS AND METHODS: Nontumorigenic human fibroblasts (CCD-45SK and Hs67), peripheral blood lymphocytes, and several human tumor cell lines derived from cervix, colon, and breast carcinomas, epidermoid carcinoma, and osteosarcoma (HeLa, HT29, MCF7, Saos-2, and A431 cell lines) were studied. Wild-type (wt) Ad type 5 and H5 dL118 Ad, a mutant with the deleted E1B region, were employed. The cells were infected at 20 plaque-forming units, and cell viability was evaluated by the crystal violet method. In the in vivo experiments, 2 x 10(6) cells from the carcinoma cell lines HeLa, A431 and HT29 were injected into nude mice. The tumorigenicity of previously infected cells and after an intratumoral injection of Ad was analyzed. The mice received whole-body gamma-irradiation. RESULTS: The H5 dL118 mutant produced a marked cytopathic effect in all of the malignant cells, surpassing that of the wt Ad; viability at 72 hours ranged from 11% to 20% for H5 dL118 Ad and from 70% to 93% for the wt Ad with respect to uninfected controls. In the in vivo experiments, a total inhibition of tumorigenicity was detected when cells were infected prior to injection and a partial and transitory decrease in tumorigenicity was detected when the mutant H5 dL118 was injected intratumorally. gamma-irradiation enhanced the in vivo antitumor effects. CONCLUSIONS: These results indicate that infection with completely E1B-deficient Ads induced a marked cytopathic effect on malignant cells that was higher than that seen for wt Ads; in addition, infection with such Ads exerts a tumor suppressor effect in vivo.

Adenoviridae↗