Phentolamine bioequivalence study

OBJECTIVE: To assess the bioequivalence of 2 tablet formulations of phentolamine (Regitine phentolamine 40 mg tablet formulation by Novartis, Brazil, as test formulation, and Vasomax, phentolamine 40 mg tablet formulation by Schering Plough S.A., Brazil, as reference formulation). METHODS: A single 40 mg oral dose of each formulation was administered to 36 male healthy volunteers. The study was conducted after screening, using an open, randomized, 2-period crossover design, a 7-day interval between doses, and wash-out period of at least 4 weeks. Plasma samples for determination of phentolamine were obtained predose and at intervals over 720 min postdose. Plasma concentrations were quantified by reversed-phase liquid chromatography coupled to tandem mass spectrometry (LC-MS-MS) with positive ion electrospray ionization using multiple reactions monitoring (MRM) method. Precision of the method was evaluated using calibration curves and plasma quality control samples. The subjects were monitored throughout the study. Systolic and diastolic blood pressure and pulse rate measurement were taken predose and at intervals up to 720 min. Tolerance of both products was good. No serious adverse reactions were reported. The pharmacokinetic parameters calculated for both compounds included: AUC(0-720 min), AUC(0-infinity), C(max), Ca and k(e). RESULTS: The maximum concentrations reached (C(max)) were compared. Regitine 40 mg formulation C(max) geometric mean ratio was 108.29% (90% CI = 98.58-118.96) of Vasomax 40 mg formulation. The areas under the curve (AUC(0-720 min)) were compared. Regitine 40 formulation (AUC(0-720 min)) geometric mean ratio was 102.33% (90% CI = 97.21-107.72) of Vasomax 40 mg formulation. CONCLUSION: Since the 90% CI for both C(max) and AUC ratio where inside the 80 to 125% interval proposed by the Food and Drug Administration, it is concluded that Regitine 40 mg tablet is bioequivalent to Vasomax for the rate and extent of absorption.     

Effect of irrigating solution and calcium hydroxide root canal dressing on the repair of apical and periapical tissues of teeth with periapical lesion

The objective of this study was to evaluate the apical and periapical repair after endodontic treatment of teeth with pulp necrosis and a chronic periapical lesion in dogs. Seventy-two root canals from four mongrel dogs were submitted to biomechanical preparation, using 5.25% sodium hypochlorite or 2% chlorhexidine digluconate as the irrigating solution. The root canals were subsequently either filled immediately with Sealapex, using active lateral gutta-percha condensation, or a calcium hydroxide root canal dressing was applied for 15 days before filling with Sealapex. After 210 days, the animals were killed by anesthetic overdose, and the obtained histological sections were stained with hematoxylin and eosin for optical microscopic analysis of apical and periapical repair. There was better histological repair in the groups with the root canal dressing (p < 0.05) than the groups with immediate obturation. Comparing the immediate obturation groups, irrigation with chlorhexidine solution resulted in better repair than sodium hypochlorite.     

Exacerbation of HIV viral load simultaneous with asymptomatic reactivation of chronic Chagas' disease

Chronic Trypanosoma cruzi infection can reactivate in patients with immunosuppression related to human immunodeficiency virus (HIV) infection, resulting in severe meningoencephalitis or myocarditis and high parasitemia. The effects of T. cruzi on HIV infection are unknown. We describe an HIV-infected patient with chronic Chagas' disease who experienced an asymptomatic T. cruzi reactivation characterized by the finding of the parasite in direct microscopic examination of blood. The patient's HIV viral load had increased simultaneously with the exacerbation of T. cruzi parasitemia and decreased to previous levels after successful antiparasitic treatment. This otherwise unexplained finding suggests that T. cruzi infection might up-regulate HIV replication, which may affect HIV disease progression. Asymptomatic reactivation of Chagas' disease has not been reported before. This could mean that the severe clinical manifestations related to the reactivation of trypanosomiasis are just the tip of the iceberg.     

The effect of intraoperative retinal manipulation on the underlying retinal pigment epithelium: an experimental study

PURPOSE: Retinal pigment epithelial changes described after vitreoretinal surgery may result from localized compression injury caused by intentional or inadvertent contact with vitreoretinal instruments. The authors evaluated these changes resulting from manipulation of the retina without frank retinal injury. METHODS: One eye each of six pigmented rabbits underwent surgery during which the inner retinal surface was touched at several points with a 20-gauge silicone-tipped subretinal fluid cannula without causing a retinal break or subretinal hemorrhage. The rabbits were followed-up with indirect ophthalmoscopy, fundus photography, and fluorescein angiography, and were killed at 1 hour, 1 week, or 2 weeks. Light microscopy was used for histopathologic evaluation. RESULTS: On fluorescein angiography, diffuse leakage noted at the injury sites significantly decreased by the fourth day and almost completely disappeared by the second week. Disruption of photoreceptor outer segments and retinal pigment epithelium in the early specimens, and irregular pigmentation, proliferation, and migration of the retinal pigment epithelium at 1 and 2 weeks were the prominent features on histopathologic examination. CONCLUSIONS: Intraoperative manipulation of the attached retina may cause significant pigment epithelium displacement and proliferation and varying degrees of disorganization of normal retinal architecture in the absence of clinically evident retinal breaks and subretinal hemorrhages.     

BC nanofibres: In vitro study of genotoxicity and cell proliferation

Nanomaterials have unusual properties not found in the bulk materials, which can be exploited in numerous applications such as biosensing, electronics, scaffolds for tissue engineering, diagnostics and drug delivery. However, research in the past few years has turned up a range of potential health hazards, which has given birth to the new discipline of nanotoxicology. Bacterial cellulose (BC) is a promising material for biomedical applications, namely due its biocompatibility. Although BC has been shown not to be cytotoxic or genotoxic, the properties of isolated BC nanofibres (NFs) on cells and tissues has never been analysed. Considering the toxicity associated to other fibre-shaped nanoparticles, it seems crucial to evaluate the toxicity associated to the BC-NFs.     

Prolonged breastfeeding in Bangladesh: indicators of inadequate feeding practices or mothers'' response to children''s poor health?

The association between breastfeeding and diarrhoeal morbidity was examined in a prevalence study of 5502 children aged 6-71 months from rural and urban Bangladesh. Breastfeeding was found to be associated with reduced prevalence of diarrhoea. This association was most pronounced at the age of six months and declined linearly to zero at approximately 30 months of age; thereafter, breastfeeding was increasingly associated with diarrhoeal illness. The linear association was found only among those children who have no access to modern health services and information, when controlling for urban and rural differences. The literature provides two opposing explanations for the positive association of prolonged breastfeeding with diarrhoeal illness. The first explanation suggests that breastfeeding can be seen as mothers' response to children's poor health. The second explanation incriminates sub-optimal child feeding practices, characterised by prolonged breastfeeding and inadequate quality and quantity of complementary foods, as the cause of malnutrition and diarrhoea. Further studies are needed to identify which explanation is correct, given the public health implications in terms of children's survival, growth and development.     

A new method to assess and measure palatal masticatory mucosa by cone-beam computerized tomography

Aim: The aim of this study was to apply a novel method to obtain high-quality images by cone-beam computerized tomography (CBCT) that consistently allowed the determination of the dimensions of the palatal mucosa.
Materials and Methods: Thirty-one patients participated in this study. At the time of the CBCT scanning, the patients wore a plastic lip retractor and wooden spatulas to retract soft tissues away from the teeth and gingiva. The thickness of the palatal mucosa was obtained at forty different locations on each patient.
Results: Retraction of the lips and cheek allowed a clear observation and measurements of the thickness of the palatal masticatory mucosa. The average thickness of the palatal mucosa was 2.92 mm in the canine area, 3.11 mm at the first pre-molar, 3.28 mm at the second pre-molar, 2.89 mm at the first molar and 3.15 mm at the second molar. Statistical differences were observed at different ages and heights of measurements.
Conclusions: A new non-invasive method to consistently obtain high-quality images of the palatal masticatory mucosa is described. Measurements of this mucosa could be obtained at different locations on the palate.