Unacceptably high levels of fluoride in commercial preparations of silver fluoride

Instead of expected fluoride ion concentrations of around 60 000 ppm, commercial preparations of 40 per cent aqueous silver fluoride were found to contain 120 000–127 000 ppm. Information received from the Western Australian Chemistry Centre which provided independent confirmation of the higher than expected [F] indicates that the currently available commercial preparations contain silver difluoride rather than silver fluoride.
In view of the potential of fluoride-containing products such as dentifrices (1000–1500 ppm F) and topical fluoride gels and solutions (6000-12 000 ppm F) to cause adverse effects if excessive quantities are ingested, any product that contains 120 000 ppm [F] should be regarded as carrying a high risk of toxicity when used on young children.     

Alpha2-adrenoceptor subtypes involved in the regulation of catecholamine release from the adrenal medulla of mice

BACKGROUND AND PURPOSE: This study was carried out to elucidate which alpha(2)-adrenoceptor subtypes mediated the inhibition of noradrenaline and adrenaline release from the adrenal medulla of mice. EXPERIMENTAL APPROACH: Isolated adrenal medullae from wild-type and alpha(2A), alpha(2B) and alpha(2C)-adrenoceptor knockout (KO) mice were placed in superfusion chambers. Catecholamine overflow was evoked by 1,1-dimethyl-4-phenylpiperazinium (500 microM) in absence or in presence of the alpha(2)-adrenoceptor agonist medetomidine. The effect of medetomidine was tested in presence of the alpha-adrenoceptor antagonists rauwolscine, WB 4101, spiroxatrine, phentolamine and prazosin. KEY RESULTS: In wild-type mice, medetomidine reduced noradrenaline and adrenaline overflow in a concentration-dependent manner (EC(50) in nM: 1.54 and 1.92; E(max) in % of inhibition: 91 and 94, for noradrenaline and adrenaline, respectively). The pK (D) values of the antagonists for noradrenaline overflow did not correlate with pK(D) values at alpha(2A), alpha(2B), or alpha(2C) binding sites. The pK (D) values of the antagonists for adrenaline overflow correlated positively with pK(D) values at alpha(2C) binding sites (opossum kidney cells). The effect of medetomidine (100 nM) on noradrenaline overflow was significantly reduced in all three alpha(2)KO mice (57, 54, 44 % inhibition, for alpha(2A), alpha(2B), and alpha(2C), respectively), whereas the effect of medetomidine on adrenaline overflow was greatly reduced in alpha(2C)KO mice (14 % inhibition). CONCLUSIONS AND IMPLICATIONS: In the adrenal medulla of mice, all three alpha(2)-adrenoceptor subtypes (alpha(2A), alpha(2B), and alpha(2C)) play an equal role in the inhibition of noradrenaline overflow, whereas the alpha(2C)-adrenoceptor is the predominant alpha(2)-adrenoceptor subtype involved in the inhibitory mechanism controlling adrenaline overflow.     

Electrophoretic patterns of tumour tissue proteins

A method of constructing pherograms is described. The study of electrophoretic patterns shown on pherograms of tumour tissue from man and animals is claimed to offer a new approach to the identification and classification of tumour tissues.     

Psoralen analogues: synthesis, inhibitory activity of growth of human tumor cell lines and computational studies

Eight psoralens have been evaluated for their ability to inhibit the in vitro growth of three human tumor cell lines representing different tumor types, MCF-7 (breast cancer), NCI-H460 (non-small cell lung cancer) and SF-268 (CNS cancer). The synthesis of four new psoralens (benzofurocoumarins) is presented as well as the results of the ab initio calculations to find the parameters that relate the structure with the antitumor activity. This work provides supplementary information that could allow the development of new psoralen analogues with this type of biological activity.     

Results of urgent liver retransplantation in the state of São Paulo, Brazil

The treatment of end-stage liver disease includes transplantation as a life-saving procedure although it has serious complications of hepatic artery thrombosis, liver dysfunction, or primary nonfunction, which frequently lead to the need for retransplantation. According to various reports, the incidence of retransplantation is around 10%. Given the critical organ shortage, the chance for a second transplant remains a controversial discussion in medical, ethical, and economic grounds because patient and graft survival rates after retransplantation are lower than those for primary transplantations. We retrospectively reviewed all of the urgent liver retransplants from October 2001 to February 2005 (52 months) by analyzing the number of retransplants, blood group, time between first and second liver transplantation, age, sex, and mortality. Data were obtained from the Transplantation System, State of Sao Paulo Health Secretariat. Among 1252 liver transplants performed during this period, 98 (7.82%) were urgent retransplantations. The primary procedure employed 955 (76.28%) deceased donors and 297 (23.72%) living donors. All 98 retransplants were performed using an organ from the pool of deceased donors. The retransplant rate was acceptable according to the literature, although we observed high rates of early mortality (<60 days), leading to a discussion of which patients had a better chance of survival and the best time to perform the second transplantation to use this scarce and precious resource in the best possible way.