Incidence and risk factors for urinary retention following laparoscopic inguinal hernia repair

Background

The incidence of postoperative urinary retention (PUR) has been reported to range from 1% to 22% in patients who have undergone laparoscopic inguinal hernia procedures. The objectives of this study were to determine the incidence of PUR and examine different risk factors that may be associated with the development of PUR in patients who have undergone laparoscopic inguinal hernia procedures.

Methods

A retrospective chart review was performed on 350 patients. Demographics, comorbidities, and operative and postoperative information were collected in patients undergoing laparoscopic inguinal hernia repair by 3 general surgeons from 2007 to 2011. Statistical analysis was done on patient demographics, medical histories, anesthesia notes, and postoperative notes to identify risk factors for the development of urinary retention after laparoscopic inguinal hernia repair.

Results

Three hundred fifty consecutive patients who underwent laparoscopic inguinal hernia repairs were reviewed. Twenty-nine patients developed PUR, an incidence of 8.3%. Age ≥60 years and history of benign prostatic hyperplasia showed significance on multivariate analysis, with odds ratios of 3.0 and 11.0 respectively (P < .05). Anesthesia time ≥2 hours (odds ratio, .75) was a contributing perioperative risk factor but only as an independent risk factor (P < .05).

Conclusions

History of benign prostatic hyperplasia, age ≥60 years, and anesthesia time ≥2 hours were significant independent risk factors for urinary retention after laparoscopic inguinal hernia repair. On multivariate analysis, only history of group and age ≥60 years showed significance. This is 1 of the largest studies to show that the development of PUR in laparoscopic inguinal hernia repair patients is a multifactorial process. Further studies should be conducted to corroborate our findings.     

One-pot pyro synthesis of a nanosized-LiMn2O4/C cathode with enhanced lithium storage properties

A simple one-pot polyol-assisted pyro-technique has been adopted to synthesize highly crystalline, carbon-coated LiMn₂O₄ (LMO/C) nanoparticles for use as a cathode material in rechargeable Li-ion battery (LIB) applications. The phase purity, structure and stoichiometry of the prepared cathode was confirmed using X-ray techniques that included high-resolution powder X-ray diffraction and X-ray absorption fine structure spectroscopy. Electron microscopy studies established that the synthetic technique facilitated the production of nano-sized LMO particles with uniform carbon coating. The prepared LMO/C cathode demonstrates excellent electrochemical properties (cycling stabilities of 86% and 77.5% and high rate capabilities of 79% and 36% within the potential windows of 3.3–4.3 V and 2.5–4.3 V, respectively). The high electrochemical performance of the LMO/C cathode is attributed to the nano-size of the LiMn₂O₄ particles enabling high surface area and hence greater lithium insertion and also the uniform amorphous carbon coating facilitating effective reduction in manganese dissolution and volume expansion during the lithium de-intercalation/intercalation reactions. In addition, cyclic voltametry and impedance characterization confirm the reversible Li-intercalation and the role of the solid electrolyte interface layer (SEI) in the stable electrochemical reaction of the LMO/C electrode. Furthermore, this study shows the efficacy of a simple and low-cost pyro-synthetic method to realize high performance nano-sized particle electrodes with uniform carbon coating for useful energy storage applications.

A simple one-pot polyol-assisted pyro-synthesized LiMn₂O₄/C cathode demonstrated remarkable lithium cycling stabilities of 86% and 19% and high rate capabilities of 77.5% and 36% at 3.3–4.3 V and 2.5–4.3V, respectively.     

A Nonionic Polyethylene Oxide (PEO) Surfactant Model: Experimental and Molecular Dynamics Studies of Kolliphor EL

Polyethoxylated, nonionic surfactants are important constituents of many drug formulations, including lipid-based formulations. In an effort to better understand the behavior of formulation excipients at the molecular level, we have developed molecular dynamics (MD) models for the widely used surfactant Kolliphor EL (KOL), a triricinoleate ester of ethoxylated glycerol. In this work, we have developed models based on a single, representative molecular component modeled with 2 force field variations based on the GROMOS 53A6_DBW and 2016H66 force field parameters for polyethoxylate chains. To compare the computational models to experimental measurements, we investigated the phase behavior of KOL using nephelometry, dynamic light scattering, cross-polarized microscopy, small-angle X-ray scattering, and cryogenic transmission electron microscopy. The potential for digestion of KOL was also evaluated using an in vitro digestion experiment. We found that the size and spherical morphology of the KOL colloids at low concentrations was reproduced by the MD models as well as the growing interactions between the aggregates to from rod-like structures at high concentrations. We believe that this model reproduces the phase behavior of KOL relevant to drug absorption and that it can be used in whole formulation simulations to accelerate the formulation development.     

Sensitive quantification of mitochondrial mutation using new Taqman probes

The A3243G mitochondrial mutation is the major cause of mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS). The severity of the disease is correlated with the heteroplasmy level of the mutation. Here we describe for the first time the validation of a real-time polymerase chain reaction (PCR) assay with Taqman locked nucleic acid (LNA) fluorescent (FAM for mutant, HEX for wild type) probes for quantification of heteroplasmy levels in a total of 18 family members from 5 Vietnamese MELAS patients carrying A3243G. Almost no background of FAM signals was detected in normal samples, indicating that the probes were allele-specific. Standard curves indicate sensitive detection at 0.1% mutants and high reliability with R² > 0.985. The correlation line between measured % mutant and expected % mutant was highly reliable, with a slope of 0.993 and R² of 0.998. All positive A3243G mutant samples pre-screened by PCR-restriction fragment length polymorphism (RFLP) were confirmed, and their heteroplasmy levels quantified to be from 3.68 to 80.85%. The heteroplasmy levels in patients were higher than in their family members and generally correlated well with the severity of their clinical symptoms. Overall, this work is the first demonstration of the application of LNA probes for sensitive and highly reliable quantification of heteroplasmy levels in human mitochondria.