[Two-dimensional equivalent mechanical modeling and finite element analysis of normal female pelvic floor system].

Objective: To construct the geometric model of the pelvic floor by a two-dimensional equivalent mechanics method, and to explore the effect of the shape and position of pelvic floor organs and tissues on the biomechanical properties of the pelvic floor under different abdominal pressure. Methods: A 28-year-old healthy and symmetrical married infertile female volunteer was included. The pelvic floor tissue was scanned in the supine position using a 3.0T magnetic resonance scanner (Philips Company, Holland). Based on the method of magnetic resonance imaging (MRI) two-dimensional parameter measurement and computer aided design, the geometric model and finite element model of the female pelvic floor were established, and the biomechanical characteristics of the pelvic floor support system under different abdominal pressure were analyzed. Results: In this study, four different working conditions of the pelvic floor force were simulated under 60, 99, 168, and 208 cmH2O (1 cmH2O=0.098 kPa) abdominal pressure loads. The trend was as follows: under the abdominal pressure load, the retrograde flexion of the uterus occurred, the cervical, the middle and upper vaginal segment and the levator anus muscle had the characteristic change of mechanical axial direction pointing to the sacrum and coccyx, and the deformation of the levator anus muscle in the horizontal direction was greater than that in the vertical direction. With the increase of the abdominal pressure, the maximum stress values of the pelvic floor whole system of healthy subjects under four different working conditions were 0.194 3, 0.389 6, 0.557 1, and 0.627 5 MPa, respectively, and the maximum displacement values were 10, 14, 21 and 25 mm, respectively. The maximum stress values of the cervical and vaginal middle and upper segment were 0.111 7, 0.161 8, 0.250 6, and 0.304 1 MPa, respectively, and the maximum displacement values were 3, 6, 9, and 11 mm, respectively. The maximum stress of the perineal body was 0.063 4, 0.119 6, 0.235 2, and 0.288 0 MPa, and the maximum displacement was 1, 2, 4, and 5 mm. The maximum stress values of the levator anus muscle were 0.194 3, 0.389 6, 0.557 1, and 0.627 5 MPa, and the maximum displacement values were 2, 4, 7, and 8 mm, respectively. The maximum stress and maximum displacement of pelvic organs increased with the increase of the abdominal pressure under different working conditions. The stress axial relationship of normal female pelvic floor was that the middle and upper segment of uterus and vagina mainly acted on the sacrococcyx and the levator anus muscle, and the lower vaginal segment acts on the perineal body. Conclusions: The two-dimensional equivalent mechanical modeling and finite element analysis of the female pelvic floor system can accurately reflect the biomechanical characteristics of the female pelvic floor, and the resultant stress direction of the pelvic organs points to the sacrum and coccyx. The sacrum and coccyx, levator anus and perineal body play important stress supporting roles in the pelvic floor system.

[Eosinophilic solid and cystic renal cell carcinoma: a clinicopathological analysis of four cases].

Objective: To study the clinicopathological characteristics and prognosis of eosinophilic solid and cystic renal cell carcinoma (ESC RCC). Methods: The clinical pathologic data of 4 cases of ESC RCC diagnosed and treated from 2017 to 2019 at the Second Hospital of Longyan City, the Second Affiliated Hospital of Fujian Medical University, and the Zhangzhou Municipal Hospital were collected. The expression of different antibodies was detected by immunohistochemistry, and the diagnosis and differentiate diagnosis were investigated. Results: The 4 ESC RCC cases included 2 males and 2 females, the average age of these patients was 40 years, ranged from 31 to 51 years. The tumors were composed of solid area mixed with giant vesicles and microcapsules of varying sizes. The cyst cavity was lined by neoplastic cells with voluminous eosinophilic cytoplasm and hobnail arrangement. The solid area appeared as diffuse flaky, dense acinar or nested arrangement, the local area was island-shaped and tubular, mixed with a small amount of histiocytes and lymphocytes. Neoplastic cells contained voluminous eosinophilic cytoplasm with obvious fine or coarse particles, eosinophilic globules in part of the cytoplasm, and intracytoplasmic vacuoles in some areas. Immunohistochemical results showed that tumor cells were CK20 expressed (3/3, 2 cases were sparsely positive and 1 case was patched strongly positive), Vimentin (4/4) and CD10 (4/4) sparsely positive, while Actin, HMB45, Melan-A, CD117 and CK7 were negative in all cases. Ki-67 proliferation index was about 1%. Two cases were followed up and the progression free survival were 18 and 24 months, respectively. Conclusions: ESC RCC has unique histomorphological manifestations, CK20(+ ) and CK7(-) are helpful for its diagnosis, and it has common molecular karyotype changes, supporting it as a unique tumor entity. The overall prognosis of the patient is good.

Correlation between Obstructive Sleep Apnea and Non-Alcoholic Fatty Liver Disease before and after Metabolic Bariatric Surgery.

BACKGROUND: Emerging evidence has revealed that obstructive sleep apnea (OSA) is associated with non-alcoholic fatty liver disease (NAFLD). However, the impact of OSA on NAFLD among obese patients undergoing metabolic and bariatric surgery (MBS), especially during follow-up period, remains unclear. OBJECTIVE: To analyze the correlation based on preoperative characteristics and postoperative conditions among bariatric patients with comorbid OSA and NAFLD. METHODS: Clinical data of patients who underwent MBS in our institution between January 2016 and June 2019 were reviewed retrospectively. Correlation analysis and linear regressions were used to identify how OSA links with NAFLD before and after treatment of MBS. RESULTS: Of 308 patients, 181 were diagnosed with OSA and enrolled in the present study, and 127 completed follow-up visits at 6 months. The proportion of NAFLD in the mild-moderate OSA and severe OSA groups was 75.0% and 96.0%, respectively. MBS was effective at improving sleep apnea and nocturnal hypoxia, as well as liver steatosis and fibrosis (P < 0.05). And we also found that there were significant correlations not only between OSA- and NAFLD-related characteristics at baseline but also between their improvements after surgery, eventually leading to similar prognosis of NAFLD for both groups (P < 0.05), no matter what presurgical differences existed. In addition, the results of the univariate and multivariate linear regression analyses supported preoperative liver/spleen Hounsfield units ratio (LSR) by computerized tomography (CT) as an independent predictor of the effect of MBS on liver steatosis. CONCLUSION: In conclusion, MBS plays a pivotal role in the control of medical conditions in obese patients with OSA and NAFLD. Given the correlation between OSA and NAFLD in the present study, in the case of both the severity at baseline as well as the improvement after surgery, OSA may pose an impact on the prognosis of NAFLD in bariatric patients.

[A study on measles and rubella antibody level in 319 pairs of mothers and infants in Songjiang District of Shanghai].

Objective: To explore serum levels of measles and rubella IgG antibodies among mothers and infants. Methods: According to the inclusion and exclusion criteria, we selected 319 puerperae and their infants in maternal hospitals of Songjiang district November 2016 to February 2017, venous blood were collected and serum measles and rubella IgG antibodies were measured using ELISA. To study the correlation between the level of measles and rubella antibodies in infants and mothers' by using the Spearman's correlation analysis. Results: The age at delivery was (29.71±4.25) years old; and the gestational age at delivery was (39.06±1.30) weeks. The positive rate and protection rate of measles antibody in puerperae were 82.5% (243/319) and 43.3% (135/319), the GMC [M (QR)] was 655.74 (251.21-1 299.02) mIU/ml. The positive rate of rubella antibody in puerperae was 61.1% (195/319), the GMC [M (QR)] was 31.34 (11.65-73.61) IU/ml. The positive rate and protection rate of measles antibody in infants were 84.1% (270/321) and 46.1% (148/321), the GMC [M (QR)] was 665.07 (279.63-1 544.07) mIU/ml. The positive rate of rubella antibody in infants was 69.5% (223/321), the GMC [M (QR)] was 40.30 (16.12-98.48) IU/ml. There was statistical difference in measles (Z=-14.64, P<0.001) and rubella (Z=-8.66, P<0.001) antibody levels between mothers and infants. There was positive correlation in measles (r=0.76, P<0.001) and rubella (r=0.86, P<0.001) antibody level between mothers and infants. Conclusion: The maternal antibody of measles and rubella had a concentration effect. The level of measles and rubella antibodies in the infants was higher than that in the mothers' and increased with the increase of the level of measles and rubella antibodies in the mothers.

Integrative analyses of transcriptome sequencing identify novel functional lncRNAs in esophageal squamous cell carcinoma.

Long non-coding RNAs (lncRNAs) have a critical role in cancer initiation and progression, and thus may mediate oncogenic or tumor suppressing effects, as well as be a new class of cancer therapeutic targets. We performed high-throughput sequencing of RNA (RNA-seq) to investigate the expression level of lncRNAs and protein-coding genes in 30 esophageal samples, comprised of 15 esophageal squamous cell carcinoma (ESCC) samples and their 15 paired non-tumor tissues. We further developed an integrative bioinformatics method, denoted URW-LPE, to identify key functional lncRNAs that regulate expression of downstream protein-coding genes in ESCC. A number of known onco-lncRNA and many putative novel ones were effectively identified by URW-LPE. Importantly, we identified lncRNA625 as a novel regulator of ESCC cell proliferation, invasion and migration. ESCC patients with high lncRNA625 expression had significantly shorter survival time than those with low expression. LncRNA625 also showed specific prognostic value for patients with metastatic ESCC. Finally, we identified E1A-binding protein p300 (EP300) as a downstream executor of lncRNA625-induced transcriptional responses. These findings establish a catalog of novel cancer-associated functional lncRNAs, which will promote our understanding of lncRNA-mediated regulation in this malignancy.

[Association between serum adipocyte fatty acid binding protein level and insulin resistance in patients with OSAS].

Objective: To investigate the association between serum adipocyte fatty acid binding protein (A-FABP) level and insulin resistance in patients with obstructive sleep apnea syndromes (OSAS). Methods: Eighty patients with snoring were monitored by overnight polysomnography (PSG) from September 2015 to July 2017, and there were 59 males and 21 females, aged from 22 to 77 years old (mean age 47±14 years old). Based on the apnea-hypopnea index (AHI), these patients were divided into three groups: primary snoring group (AHI<5/h, n=19), mild-moderate OSAS groups (5/h≤AHI≤30/h, n=23) and severe OSAS groups (AHI>30/h, n=38). The levels of A-FABP, the fasting plasma glucose (FPG), fasting insulin (FINS) and insulin resistance index (IRI) were compared between the primary snoring group and OSAS patients with different severities, and the correlations between serum A-FABP and IRI as well as PSG parameters were further evaluated using partial correlation analysis. Results: Compared with the primary snoring group [(15.6±3.5) µg/L] and mild-moderate group [(17.4±4.3) µg/L], there was a significant increase of the serum A-FABP level in the severe OSAS group [(21.4±4.6) µg/L](P=0.001, P=0.025). Additionally, after adjustment for BMI and age, serum A-FABP level showed significant positive correlations with FINS and IRI (r=0.478, P<0.001; r=0.356, P=0.035); serum A-FABP level was positively correlated with AHI and the arterial oxygen saturation (SaO(2)) < 90% time ratio in night (TS90%) (r=0.251, P=0.041 and r=0.271, P=0.035). Nevertheless, serum A-FABP level showed significant negative correlation with the lowest SaO(2) and the mean SaO(2) (r=-0.244, P=0.038 and r=-0.280, P=0.018). Conclusion: Insulin resistance and the increased level of serum A-FABP are common in OSAS patients, the level of serum A-FABP is significantly correlated with insulin resistance and nocturnal intermittent hypoxia, both of which suggest that A-FABP plays a potential role in insulin resistance in patients with OSAS.

Association of mu-opioid receptor expression with lymph node metastasis in esophageal squamous cell carcinoma.

The mu-opioid receptor (MOR), a membrane-bound G protein-coupled receptor, is the main target for opioids in the nervous system. MOR1 has been found in several types of cancer cells and reported to be involved in tumor progression and metastasis. However, the expression and clinical significance of MOR1 in esophageal squamous cell carcinoma (ESCC) remain unclear. In our study, the expression of MOR1 was confirmed in ESCC cell lines (KYSE180, KYSE150, and EC109) by Western blot. MOR1 was also detected on tissue microarrays of ESCC samples in 239 cases using immunohistochemical staining. We found that MOR1 was mainly located in the cytoplasm and occasionally occurred in the membrane or nucleus of ESCC cells. Moreover, results indicated that MOR1 expression in the cytoplasm was associated with lymph node metastasis (R = 0.164, P = 0.008, Kendall's tau-b-test). No more associations were found between MOR1 expression status and other clinical parameters. However, no statistical significant differences were found between MOR1 expression in the cytoplasm, nucleus/membrane, and the overall survival of ESCC patients (P = 0.848; P = 0.167; P = 0.428, respectively, log-rank test). Our results suggest that the cytoplasmic MOR1 may be a high-risk factor for lymph node metastasis of ESCC patients. We also hypothesize that MOR1 agonists used in ESCC patients should be prudent, and opioid receptor antagonists may be novel therapeutic drugs for ESCC patients.

Connective tissue growth factor expression in precancerous lesions of human esophageal epithelium and prognostic significance in esophageal squamous cell carcinoma.

Connective tissue growth factor (CTGF, CCN2), a secreted protein, is involved in the development and progression of esophageal squamous cell carcinoma (ESCC). However, it remains unclear how CTGF expression affects the progression of ESCC. Our study implicated differences of CTGF protein status in precancerous lesions, and retrospectively examined the associations of CTGF mRNA and protein levels with clinical prognosis in ESCC patients. Here immunohistochemistry and the quantitative real-time real-time reverse transcription polymerase were performed for predicting the CTGF protein status and mRNA levels in ESCC patients, respectively. Different degrees of CTGF protein status presented in normal human esophageal epithelium and precancerous lesions, and CTGF protein was highly expressed in ESCCs. Survival analysis showed that CTGF protein status was significantly related to poor survival of ESCC patients (P= 0.024), while no significant difference was observed between CTGF mRNA levels and the survival of ESCC patients (P= 0.196). Multivariate Cox analysis demonstrated that CTGF protein status was the independent factor in prognosis of ESCC patients. In that way, CTGF protein status might elevate the progression of ESCC, and would be significant for the diagnosis of precancerous lesions or early ESCC.

Bacterial and archaeal assemblages in sediments of a large shallow freshwater lake, Lake Taihu, as revealed by denaturing gradient gel electrophoresis.

AIMS: To explore the association of microbial community structure with the development of eutrophication in a large shallow freshwater lake, Lake Taihu. METHODS AND RESULTS: The bacterial and archaeal assemblages in sediments of different lake areas were analysed using denaturing gradient gel electrophoresis (DGGE) of amplified 16S rDNA fragments. The bacterial DGGE profiles showed that eutrophied sites, grass-bottom areas and relatively clean sites with a eutrophic (albeit dredged) site are three respective clusters. Fifty-one dominant bacterial DGGE bands were detected and 92 corresponding clones were sequenced, most of which were affiliated with bacterial phylotypes commonly found in freshwater ecosystems. Actinobacteria were detected in the centre of the lake and not at eutrophied sites whereas the opposite was found with respect to Verrucomicrobiales. Twenty-five dominant archaeal DGGE bands were detected and 31 corresponding clones were sequenced, most of which were affiliated with freshwater archaeal phylotypes. CONCLUSIONS: The bacterial community structures in the sediments of different areas with similar water quality and situation tend to be similar in Taihu Lake. SIGNIFICANCE AND IMPACT OF THE STUDY: This study may expand our knowledge on the relationship between the overall microbial assemblages and the development of eutrophication in the shallow freshwater lake.

Toxicological profile of pollutants in surface water from an area in Taihu Lake, Yangtze Delta.

The environment in urbanized areas is often contaminated with a complex mixture of toxic compounds originating from industries, agriculture and private households. Most of the contaminants end up in surface waters, such as lakes, rivers and finally the sea. Toxic contaminants may disturb the biological condition of aquatic ecosystems and be harmful for humans, if they are transported to human food or drinking water. A variety of biological tests have been introduced for monitoring the toxicological profile of aquatic ecosystems. In the present investigation, genotoxic, hormone disrupting and Ah-receptor activity was analyzed in water collected in January 1999 at Meiliang Bay, Taihu Lake, China, near to the city of Wuxi in the Shanghai area. Significant mutagenic activity could be detected in water extracts with the Salmonella/microsome assay and the arabinose resistance test. Frame shift mutations were the predominant mode of action. Ah-receptor active compounds were detected by using a luciferase reporter gene assay (CALUX-assay). The estimated toxic equivalent factor-values ranged between 134 and 232 pg TCCD-equivalents per liter lake water. The estrogen-like potential of Taihu water was estimated with two luciferase reporter gene assays using transgenic human cell lines expressing estrogen receptor alpha. Estradiol equivalents obtained with water extracts were in the range of 2.2-12.1 ng/l. We also analyzed the concentrations of 17-beta-estradiol and ethinylestradiol in the extracts using a high-pressure liquid chromatography-method. The values obtained correlated with the biologically determined estradiol equivalents, indicating that the estrogenic activity is mainly due to natural and synthetic hormones rather than xenoestrogens.

Hollow-glass waveguide delivery of an infrared free-electron laser for microsurgical applications.

The purpose of this research is to deliver free-electron-laser (FEL) pulses for intraocular microsurgery. The FEL at Vanderbilt University is tunable from 1.8 to 10.8 microm. To deliver the FEL beam we used a metallic-coated hollow-glass waveguide of 530-mum inner diameter. A 20-gauge cannula with a miniature CaF2 window shielded the waveguide from water. Open-sky retinotomy was performed on cadaver eyes. The system delivered as much as 6 x 10(5) W of FEL peak power to the intraocular tissues without damage to the waveguide or to the surgical probe.

Optic nerve sheath fenestration with a novel wavelength produced by the free electron laser (FEL).

BACKGROUND AND OBJECTIVE: To determine whether 6.45-microm free electron laser (FEL) energy can successfully perform optic nerve sheath fenestration and to compare the acute and chronic cellular responses with this surgery. STUDY DESIGN/MATERIALS AND METHODS: Optic nerve sheath fenestration was performed in rabbits by using either FEL energy (< 2.5 mJ, 10 Hz, 325-microm spot size) or a knife. The optic nerve integrity and glial response were evaluated histologically acutely or 1 month postoperatively. RESULTS: The FEL at low energy effectively cut the optic nerve sheaths with minimal reaction in the underlying nerve. With FEL or knife surgical techniques, a mild astrocytic hypertrophy only adjacent to the fenestration was observed acutely in the glial fibrillary acidic protein (GFAP) -immunoreacted sections. The chronic healing responses after either technique appeared similar with: (1) a thin fibrous scar at the fenestration site, (2) cells uniformly distributed (hematoxylin and eosin), and (3) up-regulation of GFAP and S100beta in astrocytes adjacent to the fenestration site. CONCLUSION: The FEL at low energy performs an optic nerve sheath fenestration in a small space with ease. Both FEL and knife incisions cause a similar rapid glial response near the fenestration site that remains 1 month later.

Preliminary randomized double-blind placebo-controlled trial of tryptophan combined with fluoxetine to treat major depressive disorder: antidepressant and hypnotic effects.

OBJECTIVE: Because the initial phase of treatment of depression with a selective serotonin reuptake inhibitor is often complicated by a delayed onset of action of the antidepressant or severe insomnia or both, we investigated whether tryptophan, an amino acid with both antidepressant-augmenting and hypnotic effects, would benefit patients with depression at the beginning of treatment with fluoxetine. DESIGN: Randomized, double-blind, placebo-controlled trial. PATIENTS: Thirty individuals with major depressive disorder. INTERVENTIONS: Treatment over 8 weeks with 20 mg of fluoxetine per day and either tryptophan (2 to 4 g per day) or placebo. OUTCOME MEASURES: Mood was assessed using the 29-item Hamilton Depression Rating Scale (HDRS-29) and the Beck Depression Inventory (BDI). Laboratory sleep studies were done at baseline and after 4 and 8 weeks of treatment using standard procedures. RESULTS: During the first week of treatment, there was a significantly greater decrease in HDRS-29 depression scores, and a similar trend in BDI scores, in the tryptophan/fluoxetine group than in the placebo/fluoxetine group. No significant differences were noted at later time points. With respect to sleep measures, there was a significant group-by-time interaction for slow-wave sleep at week 4. Further analysis revealed a significant decrease in slow-wave sleep after 4 weeks of treatment in the placebo/fluoxetine group, but not in the tryptophan/fluoxetine group. No cases of serotonin syndrome occurred, and the combination was well tolerated, although the 4 g per day dosage of tryptophan produced daytime drowsiness. CONCLUSIONS: Combining 20 mg of fluoxetine with 2 g of tryptophan daily at the outset of treatment for major depressive disorder appears to be a safe protocol that may have both a rapid antidepressant effect and a protective effect on slow-wave sleep. Further large-scale studies are needed to confirm these initial findings.

Endoscopic goniotomy with the free electron laser in congenital glaucoma rabbits.

PURPOSE: Goniotomy is a surgical treatment of choice to treat primary infantile glaucoma. Goniotomy has been studied in vitro in animal and human cadaver eyes with several lasers. The objective of this study was to investigate the functional and morphologic effectiveness of goniotomy with the free electron laser in comparison with conventional needle goniotomy in early congenital glaucoma rabbits. MATERIALS AND METHODS: Ten rabbits with early congenital glaucoma underwent goniotomy over 100 to 120 degrees with a needle or the free electron laser. The wavelength was 6.45 microm, and the energy level ranged from 2.2 to 3.5 mJ at 30 Hz. Because most corneas were edematous in these rabbits, an Olympus 0.8-mm diameter endoscope was coupled to the laser waveguide or the needle and inserted into the anterior chamber filled with a viscoelastic material to perform the goniotomy. Intraocular pressures were followed up to 3 weeks before an acute goniotomy was performed in the contralateral eye. All eye specimens were processed for light microscopic evaluation. RESULTS: Incision of the pectinate ligaments and underlying trabecular meshwork was visualized through the endoscope on a video monitor during the surgeries. The mean intraocular pressure decreased after free electron laser goniotomy and after needle goniotomy, and the edematous corneas became clear in some cases. Histologic study showed successful lysing of the pectinate ligaments by the free electron laser with no obvious collateral thermal damage. However, some areas of peripheral anterior synechiae occurred. Similar results were observed in needle goniotomy cases. CONCLUSIONS: The free electron laser is capable of performing goniotomy in rabbit eyes with lower intraocular pressures in treated eyes 3 weeks after surgery. The histologic results of free electron laser goniotomy are comparable to those of conventional goniotomy. The endoscope provides beneficial visualization to perform the goniotomy in eyes with edematous corneas. The rabbit with early congenital glaucoma is also a useful infantile glaucoma surgical model.

Genotoxicity of surface water samples from Meiliang Bay, Taihu Lake, Eastern China.

Taihu Lake is the third largest freshwater lake in China. Taihu Basin is one of the most densely populated and urbanized areas in this country. This area provides 15% of the GDP. Meiliang Bay is located in the north part of the Lake. It provides the municipal water source for Wuxi City. Some parts of the lake have been found to be highly polluted due to eutrophication for over a decade. Surface water (0-0.5 m) samples were collected from the Meiliang Bay by the aid of Global Position System (GPS) for positioning. Water samples were concentrated 5000 times with XAD-2 resin columns. A reverse mutation test using histidine-dependent Salmonella typhimurium strains was employed to assay the genotoxicity of the samples. The results showed that the sample from position 6 had the highest genotoxicity either in the case of activating with eucaryotic S9 system or without S9. The genotoxic effect included, at least, two different molecular mechanisms: nucleotide point substitution on DNA molecules and reading frame shifting caused by nucleotide insertion or deletion. The genotoxicity of the water body in Meiliang Bay, Taihu Lake should be kept in close monitoring.

Maximum likelihood estimation of receiver operating characteristic (ROC) curves from continuously-distributed data.

We show that truth-state runs in rank-ordered data constitute a natural categorization of continuously-distributed test results for maximum likelihood (ML) estimation of ROC curves. On this basis, we develop two new algorithms for fitting binormal ROC curves to continuously-distributed data: a true ML algorithm (LABROC4) and a quasi-ML algorithm (LABROC5) that requires substantially less computation with large data sets. Simulation studies indicate that both algorithms produce reliable estimates of the binormal ROC curve parameters a and b, the ROC-area index Az, and the standard errors of those estimates.

Half corneal light shield as a delivery system for standardized application of mitomycin C.

PURPOSE: The authors develop a simple and economical method of applying reproducible intraoperative doses of mitomycin C for glaucoma filtering surgery. METHODS: A three-part protocol was developed to study several properties of half corneal light shields (HCLSs). Part A tested the amount of mitomycin C (0.4 mg/ml) absorbed, the expansion dimensions attained, and the amount released to filter paper. In part B, the in vitro release of mitomycin C to an enucleated pig eye was examined. In part C, the in vivo release during intraoperative filtering surgery was tested. RESULTS: The amount of mitomycin C solution absorbed by the HCLSs ranged from 1.07 x 10(-2) mg to 1.19 x 10(-2) mg; expansion width ranged from 6.8 mm to 7.0 mm; expansion height ranged from 3.6 mm to 3.8 mm; expansion thickness was constant at 0.6 mm. The amount of solution released to filter paper ranged from 6.8 x 10(-3) mg to 8.6 x 10(-3) mg. The amount of solution transferred to the pig eye ranged from 1.0 x 10(-3) mg to 2.7 x 10(-3) mg. The amount of solution released in filtering surgery ranged from 2.0 x 10(-3) mg to 4.8 x 10(-3) mg. CONCLUSIONS: The contact surface area, the amount absorbed, and the amount released by each HCLS was reproducible. The uniform thickness theoretically provides a uniform distribution of mitomycin C. This method may allow standardization of intraoperative mitomycin C application, and may reduce the incidence of complications.

Five taccalonolides from Tacca plantaginea.

The isolation of five bitter-tasting steroids as minor constituents from the Chinese medicinal plant Tacca plantaginea (Taccaceae), taccalonolides G, H, I, J, and K is described. Their structures were elucidated mainly by spectroscopic methods.

Ablation rate of PMMA and human cornea with a frequency-quintupled Nd:YAG laser (213 nm).

BACKGROUND AND OBJECTIVE: As an alternative to the standard excimer laser used for PRK, we investigated the ablation rate at 213 nm of PMMA, and human corneas under controlled hydration. STUDY DESIGN/MATERIALS AND METHODS: The output of a frequency-quintupled Nd:YAG laser (213 nm) was transformed into a quasi-Gaussian beam. PMMA and corneal lenticules maintained under controlled hydration were ablated until perforation was detected. RESULTS: The ablation rate of PMMA and cornea at 213 nm were similar to that at 193 nm when radiant exposure was below 200 mJ/cm2 and increased gradually between one and two times faster than that at 193 nm when radiant exposure was > 200 mJ/ cm2. CONCLUSIONS: PMMA and cornea ablation at 213 nm are similar to that at 193 nm and are different from that at 248 nm. The difference between PMMA and cornea ablation rates should be considered when using PMMA to test ablated diopter and smoothness for photorefractive surgery.