Intraindividual Variation and Personal Specificity of Salivary Microbiota.

Salivary microbiota is a typical habitat of the human microbiome. This study intended to use salivary microbiota as a model aiming to systematically address the influence of collection methods and temporal dynamics on the human microbiota compared to personal specificity. We carried out a supervised short-term longitudinal study to evaluate the influence of the change of collection methods and sampling time point on salivary microbiota in 10 systemically and orally healthy individuals with certain confounding factors (sex, oral and general health state, medication history, physical exercise, diet, and oral hygiene behavior) controlled before and during the sampling period. The microbial profiles were analyzed by 16S rDNA V3 to V4 hypervariable region amplicon sequencing. The taxonomic structure represented by the dominant species and the weighted UniFrac distance algorithm were used to demonstrate the individual specificity and the intraindividual variation introduced by the change of collection method and sampling time point. The findings suggested individual specificity existed in salivary microbiota from individuals with similar oral and general health status. The intraindividual variation brought by the change of collection method or sampling time point might introduce remarkable perturbation with the personal specificity. Insights into the intraindividual variation and personal specificity of salivary microbiota will enhance our understanding in salivary microbiota-related research. We recommend keeping collection conditions consistent within a study to avoid interference brought by the sampling. The strategy of repeated sampling at multiple time points as representative samples, as well as thorough interpretation of the complex relationships and causality between microbiome composition and disease without the interference of temporal dynamics, is optimal for research exploring the relationship between the salivary microbiome and disease.

[Lateral endoscopic transorbital approach to middle skull base: anatomical and surgical practice study].

Objective: To investigate the anatomical and surgical approaches to middle cranial fossa through orbital lateral wall under endoscope. Methods: Cadaveric formalin fixed specimens and fresh colored silicone injected specimens were used for this study. All anatomic technical measurements were performed under 0° and 30° endoscope and infrared rays navigation. The surgical approach was designed with the bony opening on the lateral wall of orbit through which the lateral side of the middle cranial fossa could be directly entered under endoscope. One case of recurrent meningioma was performed through this surgical approach. SPSS 20.0 software was used for statistical analysis. Results: The approach can directly enter the middle cranial fossa and expose anatomic landmarks including superior orbital fissure, lateral side of cavernous sinus, foramen rotundum, foramen ovale, foramen spinosum, petrosal bone and others as well as Ⅱ, Ⅲ, Ⅳ, Ⅴ, Ⅵ cranial nerves under endoscope. The maximal bony opening through the lateral wall of orbit was measured, with a horizontal diameter of (1.38±0.68) cm, a vertical diameter of (2.02±0.32) cm, a depth of (1.44±0.42) cm from bony opening margin to the dura. The recurrent meningioma involving lateral side of the middle skull base was successfully removed by this surgical approach through lateral wall of orbit. Conclusion: Lateral transorbital endoscopic approach to the lateral side of middle skull base is a safe, feasible, and minimally invasive method, which allows surgeons to directly manipulate diseases involving this area with good visualization and minimal invasion under endoscope.

[Application of laparoscopic transection of median hepatic fissure in difficult laparoscopic liver resections].

Objective: The aim was to explore the strategy and clinical value of laparoscopic transection of median hepatic fissure (MHF) in difficult laparoscopic liver resections. Methods: First the MHF was located and marked, then the transection plane of the MHF was set. Next, the laparoscopic Multifuctional Operative Dissector (LPMOD) and the technique of curettage and aspiration were utilized to transect the liver beginning from the middle portion of the gallbladder fossa, in a caudal-to-cranial and anterior-to-posterior direction, until the clear exposure of the anterior surface of the intrahepatic inferior vena cava. Transection of the MHF was accurately achieved. Finally, dissection of the second and third porta hepatis were carefully performed and mobilization of the transected liver was achieved. This technique of laparoscopic transection of MHF was successfully performed in 13 patients in difficult laparoscopic liver resections. Results: Between April 2014 and August 2015, 13 patients received the technique of laparoscopic transection of MHF in difficult laparoscopic liver resections, including 10 cases of laparoscopic right hepatectomy, two cases of laparoscopic left hepatectomy and one case of associating liver partition and portal vein ligation for staged hepatectomy (ALPPS). The maximum size of the transected tumor was 15 centimeter. Duration of surgery was 240-430 min[Mean, 324.4±50.0]; the time for transection of the MHF was 40-118 min[mean, 66.4±22.7]. Blood loss was 200-2 000 ml[583.3±452.9]. The length of postoperative hospital stay was 6-25 days[mean, 13.2±5.2]. Seven patients received intraoperative transfusions. No postoperative intraabdominal bleeding, liver failure or other severe postoperative complications occurred. No perioperative death occurred. Conclusions: Application of laparoscopic transection of the MHF in difficult laparoscopic liver resections can help to clearly expose the second and third porta hepatis, especially in patients who have huge tumors and poor exposure for hepatic dissection. Moreover, precise location and transection of the MHF remains very important strategies of applying this technique.

Age estimation using a modified HPLC determination of ratio of aspartic acid in dentin.

Diastereomeric dipeptides were derived from the amino acid enantiomers in dentin by O-phthalaldehyde-N-acetyl-L-cysteine. The products were separated using high performance liquid chromatography (HPLC) and detected by fluorescence detector. A short analysis time (total analysis time was 15 min, including retention time, sample derivatization time and column regeneration time) was used. The sensitivity of detection was 1 pmol and high resolution (Rs = 1.5) was reached. We determined the D/L ratio of aspartic acid in dentin of 28 first premolars. The correlation value between the D/L ratio of aspartic acid and actual age was 0.9887; errors of +/- 1 year accounted for 46.4%, and no error exceeded 5 years.