Assessing the genotoxicity of two commonly occurring byproducts of water disinfection: Chloral hydrate and bromal hydrate.

Water disinfection treatments result in the formation of disinfection byproducts (DBPs) that have been linked to adverse human health outcomes including higher incidence of bladder and colorectal cancer. However, data about the genotoxicity of DBPs is limited to only a small fraction of compounds. Chloral hydrate (CH) and bromal hydrate (BH) are two trihaloacetaldehydes commonly detected in disinfected waters, but little is known about their genotoxicity, especially BH. We investigated the genotoxicity of CH and BH using a test battery that includes three in vitro genotoxicity assays. We conducted the Ames test using Salmonella bacterial strains TA97a, TA98, TA100 and TA102, and the alkaline comet assay and the micronucleus test both using Chinese hamster ovary cells. We carried out the tests in the absence and presence of the metabolic fraction S9 mix. CH did not exhibit statistically significant genotoxic effects in any of the three assays. In contrast, BH exhibited mutagenic activity in the Salmonella strain TA100 and induced statistically significant DNA lesions in CHO cells as appeared in the comet assay. The genotoxic potential of BH in both assays decreased in the presence of the metabolic fraction S9 mix. BH did not induce chromosomal damage in CHO cells. Our results show that BH exhibited genotoxic activity by causing mutations and primary DNA damage while CH did not induce genotoxic effects. Our findings highlight concerns about the higher genotoxicity of brominated DBPs in comparison to their chlorinated analogues.

The Sihler staining study of the infraorbital nerve and its clinical complication.

The infraorbital nerve (ION) is a cardinal cutaneous nerve that provides general sensation to the mid face. Its twigs are vulnerable to iatrogenic damage during medical and dental manipulations. The aims of this study were to elucidate the distribution pattern of the ION and thus help to prevent nerve damage during medical procedures and to enable accurate prognostic evaluation where complications do occur. This was achieved by treating 7 human hemifaces with the Sihler modified staining protocol, which enables clear visualization of the course and distribution of nerves without the accidental displacement of these structures that can occur during classic dissection. The twigs of the ION can be classified into the usual 5 groups: inferior palpebral, innervating the lower eyelid in a fan-shaped area; external and internal nasal, reaching the nosewing and philtrum including the septal area between the nostrils, respectively; as well as medial and lateral superior labial, supplying the superior labial area from the midline to the mouth corner. Of particular note, the superior labial twigs fully innervated the infraorbital triangle formed by the infraorbital foramen, the most lateral point of the nosewing, and the mouth corner. In the superior 3-quarter area, the ION twigs made anastomoses with the buccal branches of the facial nerve, forming an infraorbital nervous plexus. The infraorbital triangle may be considered a dangerous zone with respect to the risk for iatrogenic complications associated with the various medical interventions such as implant placement.

Biocompatibilidade entre implantes de titânio com e sem cobertura de hidroxiapatita / Biocompatibility of titanium implants with and without hydroxyapatite coating

O uso de implantes metálicos tem sido demonstrado por grande número de autores em estudos comparativos. No presente trabalho experimental, foram colocados implantes de titânio com e sem cobertura de hidroxiapatita (HA) no canal de ambos os fêmures, em ratos albinos, a de se analisarem aspectos histológicos e radiológicos da osteointegraçäo implante-osseo. As cobaias foram abatidas em quatro, doze e vinte e quatro semanas de evoluçäo, tendo sido retirados os seus fêmures, radiografados, fixados em formol 10 por cento, nos quais foram feitos cortes para estudo histológico. Evidenciou-se que implantes com cobertura de hidroxiapatita induzem à formaçäo óssea satisfatória e, em oposiçäo, em implantes sem cobertura (titânio jateado + ionizado, titânio jateado + ionizado + titânio oxidado), houve uma osteointegraçäo pobre, substituída por uma interface de tecido conjuntivo fibroso