Technique for Latex Injection and Reuse of Human Heads Preserved in Formaldehyde.

Background Understanding the anatomy of the skull base is paramount for every skull base surgeon, particularly in light of the expanded endoscopic endonasal approaches, and of the refined surgical technique used in both medial and lateral approaches. A comprehensive knowledge of anatomy is the cornerstone for a safe surgery, maximizing resection and minimizing complications. The best study method is the careful dissection of fresh human cadaveric heads in a well-equipped anatomy laboratory. In this study, we describe our protocol for preparing cadaveric specimens without vascular injection, which had been preserved in a formaldehyde solution after treating them with a dimethyldioctadecylammonium chloride/distearyl dimethyl ammonium chloride solution (commercial fabric softener) and injecting the vascular system with latex. Method Six cadaveric specimens underwent our treatment and subsequent injection of the vascular system and dissection. Results All specimens showed a good penetration of the latex and a clear improvement of the malleability of the tissues was noticed. The authors agree that this technique improved the quality of the head and facilitated studying. Conclusion We consider this an effective treatment with latex, reaching small caliber vessels, and a greater malleability and flexibility of tissues, allowing better dissections, and greater anatomical exposure, making them suitable for skull base training, study, and research.

Hepatitis B virus genotypes and mutations in the basal core promoter and pre-core/core in chronically infected patients in southern Brazil: a cross-sectional study of HBV genotypes and mutations in chronic carriers

Introduction In Brazil, little data exist regarding the distribution of genotypes in relation to basal core promoter (BCP) and precore/core mutations among chronic hepatitis B virus (HBV) carriers from different regions of the country. The aim of this study was to identify HBV genotypes and the frequency of mutations at the BCP and precore/core region among the prevalent genotypes in chronic carriers from southern Brazil. Methods Nested-polymerase chain reaction (nested-PCR) products amplified from the S-polymerase gene, BCP and precore/core region from 54 samples were sequenced and analyzed. Results Phylogenetic analysis of the S-polymerase gene sequences showed that 66.7% (36/54) of the patients were infected with genotype D (D1, D2, D3), 25.9% (14/54) with genotype A (A1, A2), 5.6% (3/54) with subgenotype C2, and 2% (1/54) with genotype E. A comparison of virological characteristics showed significant differences between genotypes A, C and D. The comparison between HBeAg status and the G1896A stop codon mutation in patients with genotype D revealed a relationship between HBV G1896A precore mutants and genotype D and hepatitis B e antigen (HBeAg) seroconversion. Genotype D had a higher prevalence of the G1896A mutation and the presence of a thymine at position 1858. Genotype A was associated with a higher ...

Hepatitis B virus genotypes and mutations in the basal core promoter and pre-core/core in chronically infected patients in southern Brazil: a cross-sectional study of HBV genotypes and mutations in chronic carriers.

INTRODUCTION: In Brazil, little data exist regarding the distribution of genotypes in relation to basal core promoter (BCP) and precore/core mutations among chronic hepatitis B virus (HBV) carriers from different regions of the country. The aim of this study was to identify HBV genotypes and the frequency of mutations at the BCP and precore/core region among the prevalent genotypes in chronic carriers from southern Brazil. METHODS: Nested-polymerase chain reaction (nested-PCR) products amplified from the S-polymerase gene, BCP and precore/core region from 54 samples were sequenced and analyzed. RESULTS: Phylogenetic analysis of the S-polymerase gene sequences showed that 66.7% (36/54) of the patients were infected with genotype D (D1, D2, D3), 25.9% (14/54) with genotype A (A1, A2), 5.6% (3/54) with subgenotype C2, and 2% (1/54) with genotype E. A comparison of virological characteristics showed significant differences between genotypes A, C and D. The comparison between HBeAg status and the G1896A stop codon mutation in patients with genotype D revealed a relationship between HBV G1896A precore mutants and genotype D and hepatitis B e antigen (HBeAg) seroconversion. Genotype D had a higher prevalence of the G1896A mutation and the presence of a thymine at position 1858. Genotype A was associated with a higher prevalence of the G1862T mutation and the presence of a cytosine at position 1858. CONCLUSIONS: HBV genotype D (D3) is predominant in HBV chronic carriers from southern Brazil. The presence of mutations in the BCP and precore/core region was correlated with the HBV genotype and HBeAg negative status.