Anatomy of the superior hypogastric plexus and its application in nerve-sparing paraaortic lymphadenectomy.

BACKGROUND: The purpose of this study was to clarify the anatomy of the superior hypogastric plexus, which would contribute to advancement of nerve-sparing paraaortic lymphadenectomy. MATERIALS AND METHODS: Eighteen cadavers were dissected and morphometrically analysed based on photographic images. Anatomical landmarks such as aortic bifurcation, transitional points of abdominal aorta to bilateral common iliac arteries, and cross point of the right ureter and pelvic brim, and cross point of sigmoid mesentery and pelvic brim were selected as reference points. RESULTS: The left lowest lumbar splanchnic nerve was located more laterally to transitional point of abdominal aorta to in 11/18 specimens, whereas the right lowest lumbar splanchnic nerve passed onto the right transitional point in only one specimen. The lowest lumbar splanchnic nerves or the superior hypogastric plexus covered the aortic bifurcation in 11/18 specimens. The superior hypogastric plexus was separate from the cross point of right ureter and pelvic brim as well as cross point of sigmoid mesentery and pelvic brim. CONCLUSIONS: The superior hypogastric plexus is at risk of injury during paraaortic lymphadenectomy because of its topography. Preservation of the superior hypogastric plexus regarding its anatomic basis during paraaortic lymphadenectomy is required.

Morphologic and morphometric characteristics of the adductor minimus in Korean: its topographic relationship with respect to neighbouring anatomical structure and clinical significance.

BACKGROUND: The aim of this study was to clarify the morphologic and morphometric characteristics of the adductor minimus (AMi) and to observe its topographic relationships relative to the adjacent anatomical structures. MATERIALS AND METHODS: This study investigated 54 thighs of 27 Korean cadavers. RESULTS: The AMi was a small and flat muscle observed in 94.4% of the specimens. It originated from the inferior ramus of the pubis as the upper part of the adductor magnus (AMa), and inserted from the lesser trochanter to the upper part of the linea aspera. The AMi was completely separate from the AMa in 63.0% of the specimens. The medial circumflex femoral artery was always found at the superior border of the AMi, while the first and second perforating arteries were found inferior to the muscle in 55.6% and 37.0% of specimens, respectively. A supernumerary muscle was found with the AMi in 42.6% of the specimens, and it originated from the inferior ramus of the pubis and inserted into the posterior side of the lesser trochanter. The obturator externus and AMi were found superoposterior and inferior to the supernumerary muscle, respectively, while the posterior branch of the obturator nerve passed underneath it. CONCLUSIONS: The results of this study may provide physicians with the accurate anatomical knowledge that they require for managing groin pain and applying a regional nerve block with ultrasound guidance in this adductor region.

Sex-dependent effects of uric acid on cerebral microbleed: a cross-sectional study in the general population.

BACKGROUND AND PURPOSE: Elevated serum uric acid (UA) is known to be associated with stroke. However, there is little information on the association between serum UA levels and cerebral microbleed (CMB), a precursor of stroke. Therefore, we investigated the association between UA and CMB in a general population taking into consideration sex-related differences. METHODS: The subjects in this cross-sectional study consisted of 2686 individuals of 40-79 years of age (1403 men and 1283 women) who underwent regular health screenings, including brain magnetic resonance imaging, at Seoul National University Hospital Health Promotion Center. Subjects were categorized into three groups according to tertiles of UA levels by sex. The presence and location of CMB were assessed by gradient-recalled echo magnetic resonance imaging. RESULTS: The prevalence of CMB was 3.8%. In multivariate logistic regression analysis by sex, the highest tertile of UA in male subjects was independently associated with the presence of CMB compared with the lowest tertile of UA (adjusted odds ratio, 2.46; P = 0.013). Meanwhile, the highest tertile of UA in female subjects was inversely associated with CMB compared with the lowest tertile of UA (adjusted odds ratio, 0.39; P = 0.040). CONCLUSIONS: High serum UA value was associated with higher prevalence of CMB in male, but lower prevalence of CMB in female subjects.

Association between salivary amylase (AMY1) gene copy numbers and insulin resistance in asymptomatic Korean men.

AIMS: Salivary amylase gene (AMY1) copy number variations (CNVs) correlate directly with salivary amylase activity and serum amylase levels. Previously, individuals with high AMY1 CNVs exhibited low postprandial glucose levels and postprandial early insulin surge, suggesting that high AMY1 gene copy numbers may play a role in lowering the risk of insulin resistance. METHODS: We verified the relationship between AMY1 CNVs and homeostatic model assessment-insulin resistance (HOMA-IR) in a cohort of 1257 Korean men aged 20-65 years who visited two medical centres for regular health check-ups, and in subgroups of current smokers and regular alcohol drinkers. Individuals with fasting plasma glucose levels > 10.0 mmol/l, HbA1c ≥ 64 mmol/mol (8.0%) or who used oral hypoglycaemic agents or insulin were excluded. RESULTS: AMY1 CNVs correlated negatively with HOMA-IR even after adjusting for covariates (e.g. BMI, systolic blood pressure, triacylglycerol, alcohol consumption, smoking and physical activity). When the participants were divided according to current smoking and alcohol consumption habits, negative correlations between AMY1 CNVs and HOMA-IR were more evident among non-smokers and regular drinkers and were non-significant among smokers and non-regular drinkers. CONCLUSIONS: Low AMY1 CNVs correlated with high insulin resistance in asymptomatic Korean men, and such a relationship presented differently according to the status of smoking and alcohol consumption.

Severe dietary lysine restriction affects growth and body composition and hepatic gene expression for nitrogen metabolism in growing rats.

Dietary lysine restriction may differentially affect body growth and lipid and nitrogen metabolism, depending on the degree of lysine restriction. This study was conducted to examine the effect of dietary lysine restriction on growth and lipid and nitrogen metabolism with two different degree of lysine restriction. Isocaloric amino acid-defined diets containing 1.4% lysine (adequate), 0.70% lysine (50% moderate lysine restriction) and 0.35% lysine (75% severe lysine restriction) were fed from the age of 52 to 77 days for 25 days in male Sprague-Dawley rats. The 75% severe lysine restriction increased (p < 0.05) food intake, but retarded (p < 0.05) growth, increased (p < 0.05) liver and muscle lipid contents and abdominal fat accumulation, increased (p < 0.05) blood urea nitrogen levels and mRNA levels of the serine-synthesizing 3-phosphoglycerate dehydrogenase gene, but decreased (p < 0.05) urea cycle arginase gene mRNA levels. In contrast, the 50% lysine restriction did not significantly (p > 0.05) affect body growth and lipid and nitrogen metabolism. Our results demonstrate that severe 75% lysine restriction has detrimental effects on body growth and deregulate lipid and nitrogen metabolism.

Establishment of an efficient multiplex real-time PCR assay for human papillomavirus genotyping in cervical cytology specimens: comparison with hybrid capture II.

OBJECTIVE: To establish an efficient multiplex real-time PCR assay for 15 human papillomavirus (HPV) genotypes, we designed multiplexing parameters and compared our PCR system with the hybrid capture (HC) II test using cervical cytology samples. METHODS: For preventing cross-reactive amplifications, variable HPV genes (E1, E2, E6, E7 and L1) were targeted. The melting temperatures of all primers and probes, and the size of the PCR product were optimized for the multiplex PCR. Our PCR system was compared with the HC II assays in the detection and genotyping of HPV infection using 173 cytology smears. Discordant cases between the two assays were verified by direct HPV DNA sequencing. RESULTS: Of 173 women, 93 (53.8%) were HPV-positive by the HC II assay and/or the multiplex real-time PCR assay. The HPV genotypes were determined in 92 (98.9%) of 93 cases by the multiplex real-time PCR and/or DNA sequencing. The agreement rate between multiplex PCR and HC II methods was 91.9% (kappa=0.84). Although the sample size of this study needs to be increased to have epidemiological significance, multiple infections and HPV 16 were the predominant type. HPV 58, 52 and 18 accounted for 25% of HPV infections. HPV 52, 58 and 31 constituted 30% of CIN 2/3. CONCLUSION: The multiplex real-time PCR system shows a good and reliable clinical performance. This in house PCR assay is fast and cost-effective for HPV genotyping and the detection of HPV co-infection in the post-HPV vaccination era.

Effects of capsazepine, a transient receptor potential vanilloid type 1 antagonist, on morphine-induced antinociception, tolerance, and dependence in mice.

BACKGROUND: Repeated morphine treatment has been shown to induce transient receptor potential vanilloid type 1 (TRPV1) expression in the spinal cord, dorsal root ganglion (DRG), and sciatic nerve of a rat model. Increased TRPV1 expression may therefore play a role in morphine tolerance. In this study, we evaluated the hypothesis that blockage of TRPV1 may be useful as an adjunctive pain management therapy. We investigated whether blockage of TRPV1 by capsazepine, a TRPV1 antagonist, affected antinociception, development of tolerance, and physical dependence on morphine in mice. METHODS: Institute of Cancer Research mice were pretreated with capsazepine and post-treated with morphine acutely and repeatedly. Antinociception and its tolerance were assessed using the hot-plate test. Morphine dependence was examined through the manifestation of withdrawal symptoms induced by naloxone in morphine-dependent mice. RESULTS: Acute capsazepine treatment (5 mg kg⁻¹, i.p.) potentiated the antinociceptive effects of morphine, as measured by the hot-plate test. Repeated co-treatment of capsazepine (2.5 mg kg⁻¹ i.p.) with morphine attenuated the development of tolerance to the antinociceptive effect of morphine. The development of morphine dependence was also reduced by capsazepine (1.25 or 2.5 mg kg⁻¹ i.p.). CONCLUSIONS: Our results suggest that TRPV1 antagonists can be used adjunctively to morphine treatment because they strengthen morphine antinociception and prevent the development of tolerance, and also physical dependence, on morphine.

Herbicide contamination of live armclad rockfish, clam and pen shell by moss-control agents used in aquariums of seafood restaurants in Korea.

Determination of simazine and diuron by high-performance liquid chromatography-ultraviolet detection (HPLC-UV) in moss-control agents, seawater and fish in aquariums was investigated and validated. The detection limits are 0.2 (simazine) and 0.4 µg l(-1) (diuron) in blank seawater, and 0.20 (simazine) and 0.30 µg kg(-1) (diuron) in blank fish homogenate, while the recoveries ranged from 93.9% to 102.4% with a relative standard deviation ≤ 9.8% for simazine and diuron. The method was successfully used in the study of simazine and diuron contamination in live fish stored in seafood restaurant aquaria in Korea. It was found that 0.4-2.3% of simazine and <0.10-3.8% of diuron were included the in moss-control agents tested. Of the 66 sampled aquarium seawaters, simazine was found to be present in four samples (3.8-42 µg l(-1)) while diuron was detected in two samples (1.3-1.6 µg l(-1)). For fish homogenates used in a bioconcentration study, simazine content ranges from 0.17 to 1.8 mg kg(-1).

Biofeedback therapy for rectal intussusception.

BACKGROUND: Surgery for isolated internal rectal intussusception is controversial due to high morbidity. Therefore, there is interest in other forms of treatment that are safe and effective. The aim of this study was to determine outcome and identify predictors for success of biofeedback therapy in patients with rectal intussusception. METHODS: We retrospectively evaluated the results of electromyography (EMG)-based biofeedback in 34 patients with rectal intussusception without any other major pelvic floor or colonic physiologic disorder. RESULTS: A total of 34 patients (7 men) had undergone at least 2 biofeedback sessions. The patients had a mean age of 68.5 years (SD=11.4 years). In the 27 patients with constipation, the frequency of weekly spontaneous bowel movements (mean+/-SD) was 2.0+/-6.8 before and 4.1+/-4.6 after biofeedback (p<0.05). The frequency of weekly assisted bowel movements decreased from 3.8+/-3.5 before to 1.5+/-2.2 after therapy (p<0.005). The number of patients who experienced incomplete evacuation decreased from 17 (63%) to 9 (33%) (p<0.05). Thirty-three percent of patients had complete resolution of the symptoms, 19% had partial improvement, and 48% had no improvement. Patients with constipation lasting less than nine years had a 78% success rate vs. 13% in patients who were constipated more than 9 years (p<0.01). In seven patients with incontinence, the frequency of daily incontinence episodes decreased from 1.0+/-0.7 before to 0.07+/-0.06 after biofeedback (p<0.05). The fecal incontinence score decreased from 13.1+/-4.2 before to 4.6+/-3.6 after treatment (p<0.005). Two patients (29%) were completely continent following biofeedback, 2 had partial improvement, and 3 (43%) had no significant improvement. There was no mortality in either group. CONCLUSIONS: Biofeedback is a safe and effective treatment option for constipation and fecal incontinence due to rectal intussusception in patients who are willing to complete the course of treatment. Long-standing constipation is less effectively cured by biofeedback.

Ischemia-related changes of adrenocorticotropic hormone immunoreactivity and its protective effect in the gerbil hippocampus after transient forebrain ischemia.

In the present study, the temporal and spatial alterations of adrenocorticotropic hormone (ACTH) immunoreactivity in the gerbil hippocampus after 5 min transient forebrain ischemia were investigated as followed up 7 days after ischemic insult, and the effects of ACTH after ischemic insult were also investigated 4 days after ischemic insult. The ectopic expression of ACTH (1-24 fragments) immunoreactive neurons in the cornus ammonis 1 (CA1) region of hippocampus and hilar region of the dentate gyrus 1 day after the ischemic insult was observed. Judging from the double immunofluorescence study, these neurons contain GABA. Four days after ischemic insult, the ACTH immunoreactivity was localized in CA1 pyramidal cells and glia near the stratum pyramidale, which normally do not express ACTH. In addition, in the saline-treated groups, the percentage of the detected Cresyl Violet positive neurons was 11.2% compared with the sham-operated group 4 and 7 days after ischemic insult. In these groups, the OX-42 immunoreactive microglia were detected in the strata pyramidale, oriens and radiatum. However, in the Org2766 (analog of ACTH)-treated group, 57.8% neurons compared with the sham-operated group were stained with Cresyl Violet 4 and 7 days after ischemic insult. In these groups, the OX-42 immunoreactive microglia were significantly reduced in the stratum pyramidale. These results suggest that transient forebrain ischemia may provoke selective ectopic and enhanced expression of ACTH in the hippocampus, and further suggest that ACTH plays an important role in reducing the ischemic damage.

The enhanced expression of c-Jun immunoreactivity in the adrenalectomized gerbil hippocampus.

Recent in vitro and in vivo studies have shown that glucocorticoids have a profound influence on the survival of hippocampal neurones, and that the depletion of glucocorticoids as a result of adrenalectomy (ADX) reduces nerve growth factor levels in the hippocampus. It is also believed that ADX is associated with the seizure susceptibility of the Mongolian gerbil. In the present study, the choronological changes of c-jun immunoreactivity were investigated after ADX in the hippocampal formations in the seizure-prone gerbil model. In the sham hippocampus, c-jun immunoreactivity was not observed in the neurones of the hippocampus proper and dentate gyrus. C-jun immunoreactive neurones appeared 3 h after ADX in the neurones of the CA1 area and dentate gyrus, and these immunoreactivities peaked 24 h after ADX and then gradually decreased. These results suggest that, in the adrenalectomized gerbil, c-jun may be expressed in the neurones of the hippocampus in compensation for glucocorticoid deficit. The result of enhanced c-jun expression of the hippocampal formation provides anatomical support for the hypothesis that c-jun may play a role in the reduction of seizure activity.

Proteolytic enzyme conjugated to SC-glucan as an enzymatic transdermal drug penetration enhancer.

The objective of this study was to investigate the effect of papain, a proteolytic enzyme, on the percutaneous absorption of drugs. To guarantee the enzyme stability during the skin penetration, papain was modified by the conjugation to SC-glucan. The enhancing activity of drug penetration was evaluated using antipyrine and indomethacin as hydrophilic and hydrophobic model drugs, respectively. The SC-glucan-papain conjugate was found to be very effective for facilitating the percutaneous absorption of antipyrine. Microscopic observations showed that the thickness of stratum corneum and viable epidermis was increased by the treatment of the SC-glucan-papain conjugate. Moreover, it induced phase separation, lacuna formation, and lamellar disruption within the stratum corneum interstices. These structural changes by the SC-glucan-papain conjugate are likely to be induced from hydrolysis of extensive crosslinking of corneocyte envelopes and intracellular proteins. However, the SC-glucan-papain conjugate showed no skin irritation according to the Draize test, which may be due to the difficulty of the SC-glucan-papain conjugate in penetrating into the skin.

Protein release microparticles based on the blend of poly(D,L-lactic-co-glycolic acid) and oligo-ethylene glycol grafted poly(L-lactide).

Bovine serum albumin (BSA), a model protein drug, was encapsulated with a microparticle based on the blend of poly(D,L-lactic-co-glycolic acid) (PLGA) and poly(L-lactide)-g-oligo(ethylene glycol) (PLLA-g-oligoEG). Effects of PLLA-g-oligoEG in the blend on degradation, characteristic properties, and release behavior of the microparticle were studied. Drug loading efficiency increased with increase in the graft frequency of oligoEG in the graft copolymer in the blend. The release of BSA was found to be more efficient for microparticles based on the blend than on the PLGA, which is due to the faster protein diffusion through the swollen phase of the hydrogel-like structure. The microparticles based on the blend showed a slower degradation and a lower pH shift compared to that of PLGA.

Rectified photocurrent of molecular photodiode consisting of cytochrome c/GFP hetero thin films.

Photoinduced electron transfer in the molecular electronic device consisting of protein-adsorbed hetero Langmuir-Blodgett (LB) film was investigated. Three kinds of functional molecules, cytochrome c, viologen, and green fluorescent protein (GFP) were used as an electron acceptor, a mediator, and a sensitizer, respectively. The hetero-LB film was fabricated by subsequently depositing cytochrome c and viologen onto the pretreated ITO or quartz glass. GFP adsorbed hetero-LB films were prepared by soaking the hetero-LB films into the buffer solution containing GFP. The MIM (metal/insulator/metal) structured molecular device was constructed by depositing aluminum onto the surface of the GFP-adsorbed hetero LB films. Due to the excitation by irradiation with a 460 nm monochromic light source, the photoinduced unidirectional flow of electrons in the MIM device could be achieved and was detected as photocurrents. The photoswitching function was achieved and the rectifying characteristic was observed in the molecular device. Based on the measurement of transient photocurrent of molecular device, the unidirectional flow of electrons was verified.

Study on gelatin-containing artificial skin IV: A comparative study on the effect of antibiotic and EGF on cell proliferation during epidermal healing.

Gelatin-hyaluronate sponge with and without antibiotic and epidermal growth factor (EGF) were prepared and compared. Four types of sponges were applied on the full-thickness dorsal skin defect of Wistar rat. The effects of antibiotic and EGF in gelatin-hyaluronate sponge on wound healing were investigated by light microscopy and image analyzer at postoperative days of 5, 12 and 21. An immunohistochemical technique, employing PC10, a monoclonal antibody against proliferating cell nuclear antigen (PCNA) was applied to wounded tissue sections. The number of PC10-positive cells was very high for the sponge with EGF at postoperative day 5, then gradually decreased with time. Also we found that antibiotics restrained the cell proliferation during the migratory phase. The sponge with both antibiotic and EGF showed good wound healing performances on the whole for a healing period. The epithelium was regenerated fast with EGF-impregnated sponges at day 5, but each sample had nearly the same length of regenerated epithelium at day 12.

Exchange of the basic domain of human immunodeficiency virus type 1 Rev for a polyarginine stretch expands the RNA binding specificity, and a minimal arginine cluster is required for optimal RRE RNA binding affinity, nuclear accumulation, and trans-activation.

The Rev regulatory protein of human immunodeficiency virus (HIV) facilitates the nuclear export of unspliced and partially spliced HIV RNAs. Using a Rev:MS2 phage coat protein fusion that could be targeted to bind and activate the Rev-responsive element (RRE) RNA or heterologous MS2 phage operator RNA, we analyzed the role(s) of the arginine-rich RNA binding domain in RNA binding and transactivation. The arginine-rich domain could be functionally replaced by a stretch of nine arginines. However, polyarginine substitutions expanded the RNA binding specificity of the resultant mutant Rev protein. Polyarginine insertions in place of residues 24 to 60 that excised the RNA binding and oligomerization domains of Rev preserved the activation for MS2 RNA, but not for the RRE. A nine-arginine insertion outside of the natural context of the Rev nuclear localization signal domain was incompatible with activation of either RNA target. Insertions of fewer than eight arginines impaired RRE activation. Interrupted lysine clusters and disruption of the arginine stretch with lysine or neutral residues resulted in a similar phenotype. Some of these mutants with a null phenotype for RRE activated the heterologous MS2 RNA target. Under steady-state conditions, mutants that preserved the Rev response for RRE RNA localized to the nuclei; those with poor or no Rev response accumulated mostly in the cytoplasm. Many of the cytoplasmically resident derivatives became nuclear when leptomycin B (LMB) treatment inhibited nuclear export of nuclear export signal-containing proteins. Mutants that had a null activation potential for either RNA target were particularly resistant to LMB treatment. Abbreviated nuclear residence times and differences in RRE binding affinity may have compromised their activation potential for RRE. High-affinity binding to MS2 RNA through the intact coat protein was sufficient to overcome the short nuclear residence times and to facilitate MS2 activation by some derivatives.

Reproducibility of colonic transit study in patients with chronic constipation.

PURPOSE: Major therapeutic decisions are rendered based on a single colonic transit study. Therefore, the aim of this study was to assess the reproducibility of colonic transit time in patients with chronic constipation. MATERIALS AND METHODS: Fifty-one patients with chronic idiopathic constipation were randomly selected to undergo two separate colonic transit tests. All clinical conditions, methodology, and patients' instructions were identical on both occasions. The gamma rate (linear correlation analysis) was undertaken between the first and second colonic transit times. Groups were divided according to the diagnoses of colonic inertia (slow-transit constipation), paradoxical puborectalis contraction, and chronic idiopathic constipation (normal-transit constipation). RESULTS: In 35 of 51 patients (69 percent), the results were identical between the two studies; however, in 16 patients (31 percent), the results were disparate (gamma correlation coefficient = 0.53; P < 0.01). The specific correlation coefficients for patients with colonic inertia, paradoxical puborectalis contraction, and chronic idiopathic constipation were 0.12, 0.21, and 0.60 (P < 0.01), respectively. Moreover, the success rate of colectomy for colonic inertia was significantly higher in patients who underwent a repeat transit study confirming inertia than in patients who underwent colectomy based on a single study. CONCLUSIONS: Overall, colonic transit time is reproducible in patients with chronic constipation. The correlation coefficient is best for patients with idiopathic constipation and worst for patients with colonic inertia. This new finding suggests that suboptimal surgical outcome may be attributable to inaccurate diagnosis. Because of this poor correlation coefficient, in patients with colonic inertia, consideration should be given to repeating the colonic transit study before colectomy to help secure the diagnosis and improve outcome.

Functional outcomes in patients with mucosal ulcerative colitis after ileal pouch-anal anastomosis by the double stapling technique: is there a relation to tissue type?

PURPOSE: The aim of this study was to evaluate any differences in functional outcome in patients with mucosal ulcerative colitis after restorative proctocolectomy and ileal pouch-anal anastomosis with use of the double stapling technique relative to the type of tissue in the stapled doughnut. METHODS: Between September 1988 and June 1997, the pathology of all patients with mucosal ulcerative colitis who underwent ileal pouch-anal anastomosis with use of the double stapling technique were reviewed. Information was obtained regarding the tissue types in the distal tissue rings (doughnuts) obtained from the stapled ileal pouchanal anastomosis. The level of anastomosis was classified according to the type of tissue in the distal doughnut: Group I- patients in whom the anal transitional zone was removed and the distal doughnut included squamous epithelium or transitional epithelium and Group II- patients in whom the anal transitional zone was preserved because the distal doughnut revealed only columnar epithelium. Functional outcomes were assessed and compared by detailed questionnaires mailed to all patients at least one year after ileal pouch-anal anastomosis surgery. RESULTS: Distal doughnuts were obtained from the stapled ileal pouch-anal anastomosis in 222 patients with mucosal ulcerative colitis. Follow-up data at a mean of 38 (range, 12-132) months were obtained in 138 (62.2 percent) patients, including 72 males, with a mean age of 46.9 (range, 13-79) years. Group I consisted of 40 patients (29 percent; 35 (25.4 percent) who had squamous epithelium and 5 (3.6 percent) who had transitional epithelium in the distal tissue rings). Group II consisted of 98 patients (71 percent) with columnar epithelium in the distal tissue rings. Age at diagnosis and operation, duration of disease, length of follow-up, and stage of pouch surgery were similar in the two groups. Incontinence scores, frequency of bowel movement, use of a protective pad, discrimination between gas and stool, use of antidiarrheals, life-style alteration, and patient satisfaction showed similar functional results between the two groups. CONCLUSIONS: The tissue type in the stapler distal doughnut did not greatly influence functional outcome. Failure to identify a relationship may attest to the variable height and composition of the anal transitional zone.

Lysozyme microencapsulation within biodegradable PLGA microspheres: urea effect on protein release and stability.

Lysozyme was encapsulated within biodegradable poly(D, L-lactide-co-glycolide) microspheres by a double emulsion solvent evaporation method for studying its release mechanism associated with protein stability problems. When urea, a protein unfolding agent, was added into the incubation medium lysozyme release rate from the microspheres increased with the increase in urea concentration. The enhanced lysozyme release was attributed to the suppression of protein aggregation, to the facilitated diffusion of unfolded lysozyme by an efficient reptile motion of unfolded protein molecules through porous channels in microspheres, and to the largely decreased extent of nonspecific protein adsorption onto the enlarged surface area of degrading polymer microspheres in the presence of urea. Encapsulating lysozyme in an unfolded form within PLGA microspheres was attempted by using urea as an excipient. This new urea-based formulation exhibited a more sustained lysozyme release profile than the control formulation, and released lysozyme from the microspheres showed a much less amount of lysozyme dimer population while maintaining a correct conformation after refolding in the incubation medium. This study provides new insights for the formulation of protein encapsulated PLGA microspheres.