[Study on the fit testing for the workers wearing hearing protection device in machinery manufacturing enterprises]

Objective: To investigate the occupational noise hazards in five machinery manufacturing enterprises, and to evaluate the individual noise reduction values and influencing factors of workers wearing hearing protection device (HPD) by individual fit testing. Methods: From November 2021 to January 2022, 5 machinery manufacturing enterprises in Bao'an District of Shenzhen were selected to conduct an occupational health survey to understand the noise exposure level of workers. The 3MTM E-A-RfitTM fitness test system was used to test the baseline individual sound attenuation value level (PAR) of the daily wear of the ear protecters for 485 workers in typical noise working positions. Workers whose PAR values could not meet the requirements of noise reduction at work were instructed to wear and repeated tests were conducted. PAR results of the workers before and after the intervention were collected and analyzed. Results: The noise workers who received the suitability test were mainly distributed in 24 types of work, the job noise exposure level was 80.2 dB (A) ~ 95.0 dB (A), and the job noise excess rate was 52.5% (138/263). The median baseline PAR [M (Q(1), Q(3)) ] for 485 workers was 6.0 (0.0, 14.0) dB. The baseline PAR of male workers, those with more than 15 years of working experience, those with more than 15 years of using ear guards, those who considered ear guards comfortable to wear, those with college degree or above, and those exposed to noise level 90 dB (A) were higher, and the difference was statistically significant (P<0.05). A total of 275 workers (56.7%) did not pass the baseline PAR test, and there was no statistically significant difference in the intervention rate of workers in different noise groups (P>0.05). PAR in subjects who did not pass baseline after intervention increased from 0.0 (0.0, 3.0) dB to 15.0 (12.0, 18.2) dB. Conclusion: The workplace noise hazard of machinery manufacturing enterprises is serious, and there is a great difference between the baseline PAR and the nominal value of the hearing guard worn by the noise exposed workers. The intervention measures can effectively improve the protective effect of wearing ear protectors.

DNAzyme-Amplified Label-Free Biosensor for the Simple and Sensitive Detection of Pyrophosphatase

The level of pyrophosphatase (PPase) expression has been suggested as a potential biomarker of various cancers, and its prognostic value has been evaluated in patients suffering from lung cancer, colorectal cancer, and hyperthyroidism. However, the detection of PPase usually needs specific materials that require complicated, time-consuming reactions with restricted linear range and sensitivity, limiting their application in early clinical diagnosis. Herein, we developed a DNAzyme-based biosensor for the detection of PPase. In the presence of PPase, pyrophosphate (PPi) and Cu2+ ions released from the PPi-Cu2+-PPi complex induce the cleavage of the DNAzyme and the corresponding substrate. An apurinic/apyrimidinic (AP) site was elaborately designed within substrates that could encase the fluorophore 2-amino-5,6,7-trimethyl-1,8-naphthyridine (ATMND). The fluorescence of ATMND was initially quenched but restored when the DNAzyme/substrate complex was hydrolyzed with the release of ATMND. In this way, the PPase activity can be estimated by detecting the increased fluorescence of the released ATMND. Under optimized conditions, the activity of PPase could be analyzed at concentrations from 0.5 to 1000 mU, with the lowest detectable concentration being 0.5 mU. This work lays a foundation for developing a DNAzyme-amplified fluorescent biosensor with a high sensitivity, a wide linear range, and single-step operation for use as an easy diagnostic for PPase analysis.

[Application of Chen's pancreaticojejunostomy technique in laparoscopic pancreaticoduodenectomy (116 cases report)]

Objective: To investigate the safety and feasibility of longitudinal transpancreatic U-sutures invaginated pancreatojejunostomy (Chen's pancreaticojejunostomy technique) in laparoscopic pancreaticoduodenectomy (LPD). Methods: Clinical data of 116 consecutive patients who underwent LPD using Chen's pancreaticojejunostomy technique in Hunan Provincial People's Hospital from May 2017 to December 2018 were retrospectively analyzed. Among these patients, 66 were males and 50 were females. The median age was 58 years old (32-84 yeas old). All 116 patients underwent pure laparoscopic whipple procedure with Child reconstruction method, using Chen's pancreaticojejunostomy technique. The intraoperative and postoperative data of patients were analyzed. Results: All 116 patients underwent LPD successfully. The mean operative time was (260.3±33.5) minutes (200-620 minutes). The mean time of pancreaticojejunostomy was (18.2±7.6) minutes (14-35 minutes). The mean time of hepaticojejunostomy was (14.6±6.3) minutes (10-25 minutes). The mean time of gastrojejunostomy was (12.0±5.5) minutes (8-20 minutes). The mean estimated blood loss was (106.0±87.6) ml (20-800 ml). Postoperative complications were: 11.2%(13/116) of cases had postoperative pancreatic fistula (POPF), including 10.3% (12/116) of biochemical fistula and 0.9%(1/116) of grade B POPF, no grade C POPF occurred; 10.3%(12/116) had gastrojejunal anastomotic bleeding; 3.4%(4/116) had hepaticojejunal anastomotic fistula; 3.4%(4/116) had delayed gastric emptying; 4.3% (5/116) had localized abdominal infection; 12.1%(14/116) had pulmonary infection; postoperative mortality were 0(0/116) and 1.7%(2/116) within 30 days and 90 days, respectively. One patient died of massive abdominal bleeding secondary to Gastroduodenal artery pseudoaneurysm rupture, the other patient died of extensive tumor recurrence and metastasis after surgery. Conclusions: Chen's pancreaticojejunostomy technique is safe and feasible for LPD.It is an option especially for surgeons who have not completed the learning curve of LPD.

[Exploration on laparoscopic hepatectomy on central liver tumor: a report of 40 cases]

Objective: To assess the safety and feasibility of the application of the laparoscopic modality in the perioperative treatment of central liver tumors. Methods: Collecting all the clinical information of a total of 40 patients with central liver tumors who received laparoscopic resection treatment carried out at Department of Hepatological Surgery of People's Hospital of Hunan Provincial from January 2016 to December 2018 to take a retrospective review. There were 19 males and 21 females.The age was (59.5±14.5) years (range: 15 to 71 years) . There were 26 cases of primary hepatic carcinoma (24 cases of hepatocellular carcinoma, 2 cases of cholangiocellular carcinoma) , 8 cases of hepatic cavernous hemangioma, 1 case of metastatic hepatic carcinoma, 5 cases of hepatocellular adenoma. The maximum diameter of tumors were (6.2±2.9) cm (range: 2 to 13 cm) . The patient's information about hepatectomy methods, blocking mode and time of blood flow, operation time, intraoperative blood loss, intraoperative blood transfusion rate, post-operative hospitalization time, perioperative reoperation and postoperative complications were collected. Results: A total of 40 patients all were treated with laparoscopic surgery. The surgical procedure was as follows: 2 patients received the right hepatic lobectomy (Ⅴ, Ⅵ, Ⅶ and Ⅷ segments) , 2 patients received the left hepatic lobectomy (Ⅱ, III and Ⅳ segments) , 13 patients received mesohepatectomy (Ⅳ, Ⅰ and Ⅷ segments) , 2 patients received left hepatic trisegmentectomy (Ⅱ, Ⅲ, Ⅳ and Ⅷ segments) , 2 patients received right hepatic trisegmentectomy (Ⅳ, Ⅴ, Ⅵ, Ⅶ and Ⅷ segments) , 7 patients received Ⅷ segmentectomy, 1 patient received Ⅳ segmentectomy, 3 patients received Ⅴ and Ⅷ segmentectomy, 5 patients received hepatic caudate lobe resection (Ⅰ, Ⅸ segments) , and 3 patients received local tumors resection.Pathological results: there were 26 cases of primary hepatic carcinoma (24 cases of hepatocellular carcinoma, 2 cases of cholangiocellular carcinoma) , 8 cases of hepatic cavernous hemangioma, 1 case of metastatic hepatic carcinoma, 5 cases of hepatocellular adenoma; the pathological reports of all malignant tumor cases all showed negative incisal edge. The operative time was (333±30) minutes (range: 280 to 380 minutes) ; the intraoperative hepatic portal occlusion period was (58±13) minutes (range: 30 to 90 minutes) ; the intraoperative hemorrhage was (173±129) ml (range: 20 to 600 ml) ; the intraoperative blood transfusion rate was 2.5% (1/40) ; the postoperative incidence of bile leakage was 2.5% (1/40) , the hospital discharge of 1 patient with bile leakage was approved after conservative treatments like T pipe decompression and adequate drainage; there was 1 case of abdominal infection and 1 case of pulmonary infection, both of which were discharged from the hospital with conservative treatments; there were no other serious postoperative complications. The postoperative hospital stay was (10.7±2.7) days (range: 6 to 16 days) ; there were no perioperative mortality and reoperation cases. Conclusion: In the centers with abundant laparoscopic hepatectomy experiences, the laparoscopic resection is proved to be safe and feasible in the perioperative treatments of central liver tumors by the highly selective cases, the adequate preoperative assessment and reasonable surgical techniques and approach.

Restoration of erectile function with intracavernous injections of endothelial progenitor cells after bilateral cavernous nerve injury in rats

Endothelial progenitor cells (EPCs) are bone marrow-derived endothelial cells capable of circulating, proliferating, and differentiating into mature endothelial cells. Circulating EPCs can be directly recruited to some extent at sites of injury, and their administration could accelerate repair or endothelialization of the damaged tissue. We investigated the effects of intracavernous injections of EPCs into the corpora cavernosa of rats with erectile dysfunction (ED) caused by bilateral cavernous nerve (CN) injury. Overall, 24 male Sprague-Dawley rats were randomized into three groups: sham surgery, vehicle-only, or EPC treatment. Rats in the EPC treatment and vehicle-only groups were subjected to bilateral CN injury before injection of EPCs or vehicle, respectively, into the corpora cavernosa. Four weeks after surgery, erectile function was assessed by measuring maximum intracavernosal pressure (ICP), change in ICP, area under the ICP curve, and ratio of change in ICP and mean arterial pressure (MAP; ΔICP/MAP). Penile tissue was histomorphometrically analyzed for the expression of neural nitric oxide synthase (nNOS), neurofilament-1 (NF-1), von Willebrand factor (vWF), endothelial NOS (eNOS), and smooth muscle cell content. Maximum ICP and all other functional parameters of erectile function were significantly reduced in the vehicle-only group vs. the sham and EPC treatment groups (all p < 0.001). Smooth muscle cell content was decreased in the vehicle-only vs. the sham and EPC treatment groups (both p < 0.01). Expressions of vWF and eNOS in the dorsal artery were significantly higher in the EPC treatment than the vehicle-only group (p < 0.05). In conclusion, EPC treatment restored erectile function in a rat model of bilateral CN injury through recruitment of EPCs toward the dorsal artery and preservation of smooth muscle cells in the corpus cavernosum. These findings elucidate the therapeutic potential of EPCs for treating ED in humans.

Infections caused by Gordonia species at a medical centre in Taiwan, 1997 to 2008

The inability of conventional identification systems to accurately identify Gordonia spp. often results in the misdiagnosis of infections by these rare pathogens, which require genomic sequencing for precise identification. In the present study, we describe nine cases of the various types of infection caused by Gordonia spp. From 1997 to 2008, 66 isolates (from 30 patients) initially identified as Rhodoccus spp. by conventional biochemical methods, by the Bacteriology Laboratory of National Taiwan University Hospital, were retrospectively analysed to assess the accuracy of species identification. Fifteen of these isolates (from nine patients) were later found to be Gordonia spp. by two molecular methods: PCR-restriction fragment length polymorphism for heat shock protein gene (hsp65) and the 16S rRNA gene sequencing analysis. Gordonia sputi (n = 8) was the most common species, followed by Gordonia terrae (n = 7). Most of the isolates were isolated from blood (n = 11), followed by soft tissue (n = 2) and eye (n = 2). Five patients presented with bacteraemia and two of these had catheter-related bloodstream infection. Two patients had soft tissue infections and another two patients had infective keratitis and conjunctivitis. The random amplified polymorphic DNA patterns for isolates from different patients were different, indicating that they were genetically unrelated. Accurate identification with molecular methods is required if the role of Gordonia spp. in causing infection is to be recognized.

Clinical significance of nontuberculous mycobacteria isolates in elderly Taiwanese patients

The aim of this study was to investigate the clinical significance of nontuberculous mycobacteria (NTM) isolates in elderly Taiwanese patients. From 2004 through 2008, patients >65 years old with NTM isolation were identified. The definitions of NTM disease followed the American Thoracic Society and Infectious Disease Society of America (ATS/IDSA) criteria. Among the 3,175 NTM isolates, Mycobacterium avium complex (MAC; n = 1,118, 35.2%) was the most prevalent species, followed by M. abscessus (n = 545, 17.2%). Among the 1,633 elderly patients with NTM isolates, the most prevalent NTM species were MAC (n = 592, 36.3%) and M. fortuitum complex (n = 311, 19.0%). NTM colonization was found in 1,339 (80.4%) patients and only 326 (19.6%) patients had NTM diseases. During the study period, the annual incidence rates (per 100,000 inpatients and outpatients) of NTM colonization and disease both increased significantly (p < 0.0001) from 10.5 to 15.8 and from 2.1 to 4.3, respectively. Isolated pulmonary NTM infections compromised 294 (90.2%) of the 326 elderly cases of NTM disease. In conclusion, this study found an increasing trend in the incidence of both NTM isolates and NTM diseases among elderly Taiwanese patients. MAC and M. abscessus were the most frequent species causing various types of NTM disease.

Corn stunt spiroplasma: isolation, cultivation, and proof of pathogenicity

A spiroplasma isolated from corn infected with corn stunt disease has been successfully cultivated in vitro. Acid formation was associated with its growth in liquid medium, and fried egg-shaped or granulated colonies developed on solid agar medium. Healthy leafhopper vectors injected with or allowed to feed on isolates from various serial passages through liquid medium were able to transmit the corn stunt agent to healthy corn plants, inducing typical corn stunt disease in the plants. The spiroplasma was reisolated and cultivated from such diseased plants and was indistinguishable morphologically from the original isolates. These results provide the first definite proof that the corn stunt disease is caused by the corn stunt spiroplasma.

Diagnostic performance of an enzyme-linked immunospot assay for interferon-gamma in extrapulmonary tuberculosis varies between different sites of disease

OBJECTIVES

To evaluate diagnostic performance of an enzyme-linked immunospot assay for interferon-gamma (T SPOT-TB) in patients with suspected extrapulmonary tuberculosis (TB).

METHODS

From January 2007 to December 2008, patients with suspected extrapulmonary TB were prospectively enrolled from 2 tertiary care hospitals.

RESULTS

A total of 138 patients with suspected extrapulmonary TB were enrolled; 50 patients had positive culture for Mycobacterium tuberculosis and 39 patients had probable TB. The sites of infection were lymph node (n = 20), pleura (n = 19), bone/joint (n = 15), urinary tract (n = 7), peritoneum (n = 7), meninges (n = 6), disseminated (n = 5), intestine (n = 3), pericardium (n = 2), skin (n = 2), throat (n = 1), neck (n = 1), and genitalia (n = 1). The overall sensitivity and specificity were 79.8% (71/89) and 81.6% (40/49). The sensitivity ranged from 100% for tuberculous meningitis, tuberculous pericarditis, and intestinal TB, 95% for lymphadenitis, to 42.9% for tuberculous peritonitis. The sensitivity of the T SPOT-TB assay was 70.6% in immunocompromised patients and 85.5% in immunocompetent patients (p = 0.09).

CONCLUSIONS

The T SPOT-TB assay can be a useful tool for diagnosing extra-pulmonary TB in immunocompetent and immunocompromised patients, particularly for tuberculous meningitis, pericarditis, lymphadenitis, and intestinal TB.

YC-1 induces apoptosis of human renal carcinoma A498 cells in vitro and in vivo through activation of the JNK pathway

BACKGROUND AND PURPOSE

The aim of this study was to elucidate the mechanism of YC-1{3-(5'-hydroxy methyl-2'-furyl)-1-benzylindazole}-induced human renal carcinoma cells apoptosis and to evaluate the potency of YC-1 in models of tumour growth in mice.

EXPERIMENTAL APPROACH

YC-1-mediated apoptosis was assessed by analysis of MTT, SRB, DAPI staining and flow cytometry analysis. Knockdown of JNK protein was achieved by transient transfection using siRNA. The mechanisms of action of YC-1 on different signalling pathways involved were studied using western blot. Fas clustering was analysed by confocal microscopy and in vivo efficacy was examined in a A498 xenograft model.

KEY RESULTS

YC-1 displayed cytotoxicity in renal carcinoma cells at 10(-7)-10(-8) M. Increased condensation of chromatin was observed and an increase in the cell population in subG1 phase. Moreover, YC-1 triggered mitochondria-mediated and caspase-dependent pathways. YC-1 significantly induced Fas ligand expression, but did not modify either the protein levels of death receptors or ligands. In addition, Fas clustering in cells responsive to YC-1 was observed, suggesting involvement of a Fas-mediated pathway. Furthermore, YC-1 markedly induced phosphorylation of JNK and a JNK inhibitor, SP600125, and siRNA JNK1/2 significantly reversed YC-1-induced cytotoxicity and protein expression. We suggest that YC-1 induced JNK phosphorylation, the upregulation of FasL and Fas receptor clustering to promote the activation of caspases 8 and 3, resulting in apoptosis. Finally, we demonstrated the antitumour effect of YC-1 in vivo.

CONCLUSIONS AND IMPLICATIONS

These data suggest that YC-1 is a good candidate for development as an anticancer drug.

Transdermal testosterone gel increases serum testosterone levels in hypogonadal men in Taiwan with improvements in sexual function

A randomized, double-blind, placebo-controlled trial was conducted to (1) evaluate efficacy and safety of transdermal testosterone gel (AndroGel) for hypogonadal men in Taiwan, and (2) observe improvements in sexual function through international index of erectile function (IIEF) scores. Eligible hypogonadal men were randomized to receive 50 mg/day transdermal testosterone gel (TTG) or placebo for 3 months. Primary end point was change from baseline in total testosterone (TT) and free testosterone (FT). Secondary end points were change from baseline in serum hormone levels (such as dihydrotestosterone (DHT), estradiol (E2), luteinizing hormone (LH), follicle-stimulating hormone (FSH) and sex-hormone-binding globulin (SHBG)) and changes in IIEF scores. Safety evaluations included adverse events (AEs) and skin irritation assessment. Compared with baseline, the TTG group (n=20) had statistically significant increases in mean TT levels at month 1 (P=0.024) and month 2 (P=0.025), but no significant changes at month 3. TT levels in the placebo group (n=18) showed no statistically significant change at any visit. Changes in FT levels paralleled changes in TT levels in both groups. TTG group IIEF scores were significantly increased at month 3 (P=0.01), compared with a decline in placebo scores. No drug-related AEs occurred in the TTG group; the placebo group had 2 AEs (mild skin rash). In conclusion, TTG effectively restores serum TT and FT levels to a normal physiological range for hypogonadal men in Taiwan and improves sexual function.

Skin and soft tissue infection caused by non-tuberculous mycobacteria

SETTING

A medical centre in Taipei, Taiwan.

OBJECTIVE

To investigate the trend and characteristics of patients with non-tuberculous mycobacteria (NTM) related skin and soft tissue infection.

DESIGN

A total of 63 patients with culture-proven diseases were identified from January 1997 to December 2004. The medical records of all patients were reviewed.

RESULTS

Twenty-seven patients were infected with rapidly growing mycobacteria (RGM), 19 with Mycobacterium marinum, six with M. avium complex (MAC), five with M. kansasii and six with other species. Most patients presented with a protracted cutaneous lesion without systemic symptoms, and two thirds of the patients had a history of exposure. Seventy-three per cent of the lesions involved the extremities. Underlying illness with suppressed immunity was documented in 30.2% of the patients, and was most prevalent in patients with MAC (100%) and M. kansasii (60%). Of the patients, 62% underwent at least one surgical intervention, and 77.8% received treatment with different antimicrobial combinations. Most patients (86%) recovered completely. Granulomatous inflammation was found in 88.9% of biopsied tissue associated with M. marinum infection, 31.8% with RGM and 25.0% with MAC.

CONCLUSION

A combination of surgery and antimicrobials cured most patients with microbiologically proven localised NTM skin and soft tissue infection.

Characteristics of natural organic matter degradation in water by UV/H2O2 treatment

This study evaluated the UV/H2O2 system for degradation of natural organic matter in water. The photolysis experiments were conducted in a 10-l batch reactor using a 450-watt high-pressure mercury vapor lamp as the light source. The addition of H2O2 in water greatly improved the rate of humic acid degradation by UV light and 90% of the humic acid was removed within 30 min of photolysis. Kinetic data showed that the first-order reaction could be used to describe the kinetics of both humic acid oxidation and H2O2 decomposition, and the optimum H2O2 dose was 0.01%-0.05% for humic acid oxidation. It was also observed that the absorption of UVC (UV with wavelength between 200 and 280 nm) is responsible for the dissociation of H2O2 to generate the reactive hydroxyl radicals. Depending on the initial dosages, the H2O2 added to the system can be completely decomposed by UV within 50 to 90 minutes. Upon UV irradiation, the humic intermediates with smaller molecular sizes increase as a result of the degradation of larger humic substances. Photolysis of surface water also shows that the UV/H2O2 was effective in reducing trihalomethanes (THMs) formation in treating surface water with high contents of organic precursors. The distribution of THMs shifted from chlorine-THMs to bromine-THMs after UV/H2O2 treatments when bromide was present in water. However, higher H2O2 dosages would be necessary for the photolysis of surface water containing high concentrations of organic THM precursors. As observed from the Fourier transform infrared (FTIR) spectra, the functional groups of treated humic acids were destructed significantly, including -OH (from -COOH and -COH), aromatic -C=C, and -C=O conjugated with aromatic rings.

Estimating the delay of the fMRI response

We propose a fast, efficient, general, simple, valid, and robust method of estimating and making inference about the delay of the fMRI response modeled as a temporal shift of the hemodynamic response function (HRF). We estimate the shift unbiasedly using two optimally chosen basis functions for a spectrum of time shifted HRFs. This is done at every voxel, to create an image of estimated delays and their standard deviations. This can be used to compare delays for the same stimulus at different voxels, or for different stimuli at the same voxel. Our method is compared to other alternatives and validated on an fMRI data set from an experiment in pain perception.

A general statistical analysis for fMRI data

We propose a method for the statistical analysis of fMRI data that seeks a compromise between efficiency, generality, validity, simplicity, and execution speed. The main differences between this analysis and previous ones are: a simple bias reduction and regularization for voxel-wise autoregressive model parameters; the combination of effects and their estimated standard deviations across different runs/sessions/subjects via a hierarchical random effects analysis using the EM algorithm; overcoming the problem of a small number of runs/session/subjects using a regularized variance ratio to increase the degrees of freedom.

Lactate dehydrogenase genes of caiman and Chinese soft-shelled turtle, with emphasis on the molecular phylogenetics and evolution of reptiles

L-Lactate dehydrogenase (LDH) cDNAs encoding for LDH-A(4) (muscle) and LDH-B(4) (heart) isozymes from caiman (Caiman crocodilus apaporiensis) belonging to the order Crocodilia and Chinese soft-shelled turtle (Pelodiscus sinensis) belonging to the order Chelonia were sequenced. The phylogenetic relationships of the newly determined cDNA and their deduced protein sequences, as well as the previously published sequences of vertebrate LDH isozymes, were analyzed by various phylogenetic tree construction methods. These results indicated that Chelonia is indeed more closely related to Crocodilia. The divergent times between caiman and alligator, turtle and soft-shelled turtle, and Chelonia and Crocodilia were estimated to be approximately 36, 100 and 177 million years, respectively.

Role of cupric ions in the H2O2/UV oxidation of humic acids

The purpose of this study is to reveal the role of cupric ions as a natural water contaminant in the H2O2/UV oxidation of humic acids. Humic acids are naturally occurring organic matter and exhibit a strong tendency of complexation with some transition metal ions. Chlorination of humic acids causes potential health hazards due to formation of trihalomethane (THM). The removal of THM precursors has become an issue of public concern. The H2O2/UV process is capable of mineralizing humic acids due to formation of a strong oxidant, hydroxyl radicals, in reaction solution. Experiments were conducted in a re-circulated photoreactor. Different cupric concentrations (0-3.8 mg/l) and different pH values (4-9) were controlled to determine their effects on the degradation of humic acids, UV light absorbance at 254 nm, and H2O2. The presence of cupric ions inhibits humic mineralization and decreases the rate of destruction of humic acids which absorb UV light at 254 nm. On the other hand, the higher the cupric concentration, the lower the H2O2 decomposition rate. In the studied pH range, the minimum of total organic carbon (TOC) removal occurs at pH = 6 in the presence of 2.6 mg/l of cupric ions; both acidification (pH = 4) and alkaline condition (pH = 9) lead to a better removal of TOC. It is inferred from this study that the cupric-complexed form of humic acids is more refractory than the non-complexed one.

Analysis of native microflora and selection of strains antagonistic to human pathogens on fresh produce

The native microflora of three types of produce (green bell peppers, Romaine lettuce, and prepeeled baby carrots) and two types of sprouting seeds (alfalfa and clover) were investigated. Aerobic plate count (APC) for each produce or seed type as determined on Pseudomonas agar F (PAF) with incubation at 28 degrees C was in the range of 4 to 7 log CFU per g of tissue or seed. There was no significant difference (P > or = 0.05) in APC when the determinations were made with three agar media including PAF, brain heart infusion agar, and plate count agar. However, the APC as determined from plates that were incubated at 28 degrees C was significantly (P < or = 0.05) higher than with incubation at 37 degrees C. Fluorescent pseudomonads accounted for 23 to 73% of APC and 6 to 18% of APC recovered from carrots, pepper, and lettuce were pectolytic. Forty-eight strains of pectolytic bacteria were randomly isolated and identified, respectively, as members of the genera of Pseudomonas, Erwinia, Bacillus, Xanthomonas, or Flavobacterium. Lactic acid bacteria and/or yeast were consistently isolated from baby carrots, lettuce, and sprouting seeds (alfalfa or clover) but not from green bell peppers. Approximately 120 strains of indigenous microflora were tested for their ability to inhibit the growth of Salmonella Chester, Listeria monocytogenes, Escherichia coli, or Erwinia carotovora subsp. carotovora on PAF. Six isolates capable of inhibiting the growth of at least one pathogen were isolated and identified, respectively, as Bacillus spp. (three strains), Pseudomonas aeruginosa (one strain), Pseudomonas fluorescens (strain A3), and yeast (strain D1). When green pepper disks were inoculated with strains A3 and D1, the growth of Salmonella Chester and L. monocytogenes on the disks was reduced by 1 and 2 logs, respectively, over a period of 3 days. Application of strains A3 and D1 as potential biopreservatives for enhancing the quality and safety of fresh produce is discussed.

Hydroxyl radical scavenging role of chloride and bicarbonate ions in the H2O2/UV process

Simultaneous effect of inorganic anions, such as chloride and bicarbonate ions, on the scavenging of hydroxyl radicals (HO*) in the H2O2/UV process is the focus of this paper. The model compound of n-chlorobutane (BuCl) was used as the probe of HO*. By changing the pH conditions (2-9) and the concentrations of NaCl (0.25-2500 mM) and NaHCO3 (25 mM), the variation of HO* concentrations and the rate of H2O2 decomposition were compared. In general, the BuCl and H2O2 follow closely the first-order reaction within the first 10 and 40 min, respectively. In the presence of chloride alone at the pH range of 2-6, the HO* concentration in the reaction mixture increases with the increase of pH, and the HO* concentration at pH = 6 is 100 times of that at pH = 2. Including bicarbonate species in the solution, the peak HO* concentration was found at a certain pH, which shifts from 4, 5, to 5-7, as the molar ratios of chloride/bicarbonate species increase from 1 to 100. In addition, without bicarbonate species HO* concentration decreases significantly with increasing chloride concentration but remained rather unchanged beyond 1250 mM. In contrast, the HO* scavenging in the presence of bicarbonate species became relatively significant only when the chloride concentration reached beyond 250 mM. Throughout all experiments of different water quality conditions, the H2O2 decomposition rate remains rather unchanged.

Inhibition of the expression of inducible nitric oxide synthase and cyclooxygenase-2 in macrophages by 7HQ derivatives: involvement of IkappaB-alpha stabilization

Nitric oxide is an important biological mediator associated with multiple pathophysiological phenomena, such as platelet aggregation, vasodilation, septic shock, and autoimmune diseases. Prostaglandins, derived from cyclooxygenases, play prominent roles in homeostasis and inflammation. In this study, we characterized the effects of 7HQ derivatives (7-[(4-methylene-5-oxo-2-R-2-tetrahydrofuranyl) methoxy]-3,4-dihydrocarbostyril, where R is methyl, phenyl, p-fluorophenyl and p-phenylphenyl; 7HQ-1,-2,-3 and-4, respectively) in murine RAW 264.7 cells, a macrophage-like cell line. Lipopolysaccharide, the active component of endotoxin, significantly induced the expression of inducible nitric oxide synthase and cyclooxygenase-2, leading to the accumulation of nitrite and prostaglandin E(2), respectively. These actions of lipopolysaccharide were inhibited by 7HQ derivatives; additionally, the inhibition of the expression, rather than the activity, of inducible nitric oxide synthase correlated well with that of nitric oxide formation. Western blotting and electrophoretic mobility shift assay results demonstrated that the 7HQ derivatives could effectively inhibit IkappaB-alpha degradation and nuclear factor kappaB (NF-kappaB) translocation. At higher concentrations, 7HQ derivatives also inhibited cyclooxygenase-2 enzyme activity. These results suggest that 7HQ derivatives exhibit inhibitory effects on lipopolysaccharide-induced nitric oxide production and expression of inducible nitric oxide synthase and cyclooxygenase-2 through inhibition of IkappaB-alpha degradation and NF-kappaB activation.

Effectiveness of transperitoneal and trans-retroperitoneal laparoscopic adrenalectomy versus open adrenalectomy

PURPOSE

This study compared the effectiveness of laparoscopic adrenalectomy, using either a transperitoneal or trans-retroperitoneal approach, with that of open adrenalectomy in patients with benign adrenal tumors.

METHODS

From February 1995 to April 2000, laparoscopic adrenalectomy was performed on 31 patients with adrenal tumors, including 16 aldosteronomas, 10 Cushing's adenomas, three nonfunctioning tumors, and two pheochromocytomas. A lateral trans-retroperitoneal approach was used for the first 16 patients and a lateral transperitoneal approach was used for the last 15 patients. Twenty-one patients who received open adrenalectomy during the same period served as a control group. Comparisons were made between laparoscopy and open groups, and between transperitoneal and trans-retroperitoneal groups.

RESULTS

Conversion to open adrenalectomy was necessary in two cases--both in the trans-retroperitoneal group during the first 2 years of the study period. No other intraoperative complications occurred and blood transfusion was not used. Compared with the open group, the laparoscopic group had less blood loss (71 vs 124 mL), resumed oral feeding earlier (28 vs 60 hr), required less postoperative narcotics (45 vs 120 mg meperidine), and had shorter postoperative hospital stays (4.9 vs 7.6 days) (all p < 0.05). The mean operative time was longer in the laparoscopic group (203 vs 123 min, p < 0.001). There were no significant differences between the transperitoneal and trans-retroperitoneal laparoscopy groups in any of the studied parameters, except that the operative time was longer in the trans-retroperitoneal laparoscopy group (244 vs 166 minutes, p < 0.01).

CONCLUSIONS

Decreased blood loss, less postoperative pain, earlier resumption of oral feeding, and shorter hospital stays were achieved in patients undergoing laparoscopic adrenalectomy. These findings indicate that laparoscopic adrenalectomy is the treatment of choice for benign adrenal tumors. The transperitoneal approach yielded shorter operative time than the trans-retroperitoneal approach, because it offered a clearer view and familiar landmarks.

Photodegradation of humic acids in the presence of hydrogen peroxide

A batch photoreactor was used to evaluate the UV/H2O2 oxidation process for the removal of humic acids in water. A 450-W UV lamp with high-pressure mercury vapor was employed as the light source. The residues of humic acids and hydrogen peroxide were measured for assessment of process performance and understanding of process reaction behavior. The UV photolysis alone can play an important role in the degradation of humic acids. The presence of hydrogen peroxide was found to promote the degradation efficiency. However, excessive dosage of H2O2 does not further improve the degradation of humic acids. On the contrary, the lower the H2O2 dosage the higher the amount of humic acids which can be removed. Aeration with air does not favor the removal efficiency of humic acids as the oxidation lasts for a sufficiently long time. The presence of carbonate species deteriorates the humic acids' removal, whereas it results in a larger amount of H2O2 decomposition.

Effect of percent free prostate-specific antigen measurement on improving the specificity of serum prostate-specific antigen testing in Taiwanese patients

BACKGROUND AND PURPOSE

Measurement of percent free prostate-specific antigen (fPSA) has been shown to enhance the diagnostic performance of traditional serum PSA determination. We sought to determine whether measurement of percent fPSA could improve the specificity of serum total PSA testing in the detection of prostate cancer in Taiwanese patients with intermediate serum PSA concentrations.

METHODS

The medical records of 211 patients examined from March 1998 through March 2000 were analyzed retrospectively; all had a serum total PSA concentration of between 4.1 and 20.0 ng/mL and negative digital rectal examination (DRE) findings, and had undergone a prostate biopsy. Biopsy results were correlated with the serum total PSA concentration and percent fPSA, which were determined using a microparticle enzyme immunoassay. Percent fPSA was calculated as the ratio of fPSA to total PSA multiple by 100. The sensitivity and specificity were calculated and the receiver operating characteristic (ROC) curves were generated from different cutoff values of percent fPSA and total PSA.

RESULTS

Thirty-four patients (16.1%) had positive biopsy results (prostate cancer). Patients with positive biopsy results had significantly lower percent fPSA values than those with negative results (11.7% vs 16.0%, p < 0.001). Patients with a lower percent fPSA (< 10%) had a higher probability of a positive biopsy result than those with a high percent fPSA (> 20%) (positive biopsy rate, 29% vs 10%, p < 0.05). Using a cutoff value of 25% fPSA or below, the sensitivity, specificity, and positive predictive value in differentiating patients with positive biopsy results from those with negative results were 97%, 13%, and 18%, respectively. Consequently, 27 unnecessary biopsies could have been avoided at the cost of missing one cancer. The area under the ROC curve was 0.68 for percent fPSA and 0.63 for total PSA (p > 0.05).

CONCLUSIONS

For Taiwanese patients with a serum PSA concentration of between 4.1 and 20.0 ng/mL, the incidence of prostate cancer is relatively low; measurement of percent fPSA only weakly enhances the specificity of serum PSA testing in detecting prostate cancer.

Influence of pH on the dewatering of activated sludge by Fenton's reagent

The specific filtration resistance, moisture, and SVI were used to evaluate the influence of pH on the filtration and dewatering efficiencies when applying Fenton's reagent to treat the excess sludge. The excess sludge used in this study was obtained from the wastewater treatment plant of An-Ping Industrial Park in Tainan, Taiwan. Results show that initial pH has no significant effect on the filtration efficiency of sludge by using the Fenton (Fe2+/H2O2) system as the treatment process. However, the reduction of specific resistance by Fenton-like (Fe3+/H2O2) process decreased suddenly to a level similar to that obtained from the control experiment at initial pH > 4.5. For the moisture of cake sludge, both Fenton and Fenton-like systems have the same tendency; the moisture of cake sludge increased slightly with increasing the initial pH. The SVI values for Fenton process decreased with increasing the initial pH, but the opposite result was obtained from the Fenton-like and control system; higher pH was not favorable for the sludge settling.

Response to trisodium phosphate treatment ofSalmonellaChester attached to fresh-cut green pepper slices

A laboratory model using green pepper disks was developed to investigate the attachment of Salmonella Chester on plant tissue and to evaluate the effectiveness of sanitizer agents in inactivating attached bacteria on fruits. Pepper disks (14 mm in diam, and 3-4 mm in thickness) were immersed in a bacterial suspension containing 1.5 × 107cfu·mL-1of S. Chester for 30 s and subsequently air-dried at room temperature for 10 min. Approximately 30% of the bacteria retained on the disk after immersion were firmly attached and could not be removed by two washes and agitation. A positive correlation was observed between the number of bacteria attached and the concentration of bacteria in the suspension. Population studies and scanning electron microscopic examinations revealed that attachment of S. Chester on pepper disks occurred mainly on the surfaces of injured (cut) tissue but rarely on the unbroken skin. When inoculated disks were treated with 3% to 12% (w/v) of trisodium phosphate (TSP) at pH 12.3 for 5 min, the population of bacteria on the disk was reduced by 10- to 100-fold. A small portion (0.7% to 7.1%) of bacteria attached to the disk were either resistant to or protected from the TSP treatment. When the pH of TSP solution was reduced from 12.3 to 4.5, the effectiveness of TSP in inactivating S. Chester on pepper disks was reduced by 26%. This study shows that surfaces of injured fruit tissue are the principal sites for bacterial attachment, and a small portion of the bacteria attached to the tissue are resistant to the sanitizer treatment. Avoiding mechanical injuries to fresh fruits during and after harvest would reduce the chance of pathogen attachment and contamination on green pepper and fruits of similar nature.Key words: Salmonella, attachment, detachment, plant tissue, sanitizer treatment.

Correlation of cervical vertebra maturation with hand-wrist maturation in children

The purpose of this study was to evaluate the reliability of cervical vertebra maturation as an indicator of skeletal age during the circumpubertal period. This was determined by correlating cervical vertebra maturation to hand-wrist maturation. The vertebral skeletal age was assessed using lateral cephalometric radiographs according to maturity indicators modified from Lamparski. The hand-wrist skeletal age was evaluated in radiographs with the system developed by Fishman. The sample consisted of 503 subjects (244 boys and 259 girls), aged 8 through 18 years. The Spearman rank correlation coefficients and Wilcoxon sign rank test showed that a statistically significant relationship existed between the two assessments. Both the intra- and inter-judge tests of reliability displayed no significant differences. The results of this study indicate that skeletal age assessment made from the maturational changes of cervical vertebrae were reliable, reproducible and valid.

Decolorization of textile wastewater by photo-fenton oxidation technology

This paper describes the use of photo-fenton process for color removal from textile wastewater stream. The wastewater sample to be treated was simulated by using colorless polyvinyl alcohol (PVA) and reactive dyestuff of R94H. As a result, the hydroxyl radical (HO*) oxidation can effectively remove color, but the chemical oxygen demand (COD) was removed in a slight degree. The color removal is markedly related with the amount of HO* formed. The optimum pH for both the OH* formation and color removal occurs at pH 3-5. Up to 96% of color can be removed within 30 min under the studied conditions. Due to the photoreduction of ferric ion into ferrous ion, color resurgence was observed after 30 min. The ferrous dosage and UV power affect the color removal in a positive way, however, the marginal benefit is less significant in the higher range of both. PVA as the major background COD of a textile wastewater stream inhibits the color removal insignificantly as its concentration increases.

Attachment and growth of Salmonella Chester on apple fruits and in vivo response of attached bacteria to sanitizer treatments

Attachment and growth of Salmonella Chester on fresh-cut apple disks and in vivo response of attached bacteria to sanitizer treatments were investigated. Apple disks (14 mm in diameter and 3 to 4 mm in thickness) were immersed in a bacterial suspension that contained 8.17 log CFU/ml of Salmonella Chester and air dried at room temperature for 10 min. After two rinses, the population of Salmonella Chester retained on apple disks that contained no skin was 13 to 19% higher than that retained on disks that contained skin, indicating that Salmonella Chester attached more firmly to the surfaces of injured tissue than to the unbroken skin. The number of bacteria attached to the disk was not affected by the immersion time but was directly proportional to the concentration of bacteria in the suspension. The distribution of artificially inoculated Salmonella Chester on the surfaces of three different parts of whole fruit was determined; 94% of attached bacteria was found on the stem and calyx cavity areas and 6% on the skin of the remaining area of the fruit. Despite their acidic pH (4.1), apple disks supported the growth of Salmonella Chester at 20 degrees C but not at 8 degrees C. All four sanitizers tested in the study, including 6% hydrogen peroxide, 2% trisodium phosphate, 0.36% calcium hypochlorite, and 1.76% sodium hypochlorite, were effective in reducing the population of Salmonella Chester on apple disks by 1 to 2 logs. However, 5 to 13% of bacteria survived the sanitizer treatments. Hydrogen peroxide, which reduced the population of Salmonella Chester on skin by 3 to 4 logs and the population of bacteria on stem or calyx by 1 to 2 logs, was the most effective among the four sanitizers tested. Firm attachment of bacteria on calyx, stem, and injured tissue and partial resistance of attached bacteria to sanitizer treatments are two major obstacles to be considered when developing methods for cleaning and decontaminating apple fruits destined for juice production and fresh consumption.

Differential expression of four human dynamin-like protein variants in brain tumors

Dynamin-like protein, a large GTP-binding protein, has recently been cloned, and studies have suggested that it is involved in the formation of coated vesicles. In this report, the differential expression of four human dynamin-like protein splice variants (HdynIV-wildtype [WT], -11, -26, and -37) from various brain tumors was identified by reverse transcription/polymerase chain reaction (RT-PCR). One novel variant (HdynIV-11), not described previously, was identified. The four alternatively spliced variants exhibited tissue specificity in normal tissues. The HdynIV-WT was strongly expressed in the brain, whereas HdynIV-37 was expressed in all tissues examined. Moreover, HdynIV-26 was dominant in the liver and apparently overexpressed in all astrocytomas and most meningiomas and adenomas. This report suggests that HdynIV-26 may cause aberrant protein trafficking and alter vesicle formation in brain tumors. Our results also suggest that dynamin-like protein is associated with various brain tumors and, more importantly, that aberrant expression of the HdynIV-26 variant may play a role in brain tumorigenesis.

Antiplatelet effect of marchantinquinone, isolated from Reboulia hemisphaerica, in rabbit washed platelets

Platelet activation is involved in serious pathological situations, including atherosclerosis and restenosis. It is important to find efficient antiplatelet medicines to prevent fatal thrombous formation during the course of these diseases. Marchantinquinone, a natural compound isolated from Reboulia hemisphaerica, inhibited platelet aggregation and ATP release stimulated by thrombin (0.1 units mL(-1)), platelet-activating factor (PAF; 2 ng mL(-1)), collagen (10 microg mL(-1)), arachidonic acid (100 microM), or U46619 (1 microM) in rabbit washed platelets. The IC50 values of marchantinquinone on the inhibition of platelet aggregation induced by these five agonists were 62.0 +/- 9.0, 86.0 +/- 7.8, 13.6 +/- 4.7, 20.9 +/- 3.1 and 13.4 +/- 5.3 microM, respectively. Marchantinquinone inhibited thromboxane B2 (TxB2) formation induced by thrombin, PAF or collagen. However, marchantinquinone did not inhibit TxB2 formation induced by arachidonic acid, indicating that marchantinquinone did not affect the activity of cyclooxygenase and thromboxane synthase. Marchantinquinone did inhibit the rising intracellular Ca2+ concentration stimulated by the five platelet-aggregation inducers. The formation of inositol monophosphate induced by thrombin was inhibited by marchantinquinone. Platelet cAMP and cGMP levels were unchanged by marchantinquinone. The results indicate that marchantinquinone exerts antiplatelet effects by inhibiting phosphoinositide turnover.

Genetic and biochemical characterization of an exopolygalacturonase and a pectate lyase from Yersinia enterocolitica

Yersinia enterocolitica, an invasive foodborne human pathogen, degrades polypectate by producing two depolymerizing enzymes, pectate lyase (PL) and polygalacturonase (PG). The gene encoding the PG activity, designated pehY, was located in a 3-kb genomic fragment of Y. enterocolitica ATCC 49397. The complete nucleotide sequence of this 3-kb fragment was determined and an open reading frame consisting of 1803 bp was predicted to encode a PG protein with an estimated M(r) of 66 kDa and pI of 6.3. The amino acid sequence of prePG showed 59 and 43% identity to that of the exopolygalacturonase (exoPG) of Erwinia chrysanthemi and Ralstonia solanacearum, respectively. The Y. enterocolitica PG overproduced in Escherichia coli was purified to near homogeneity using perfusion cation exchange chromatography. Analysis of the PG depolymerization products by high performance anion-exchange chromatography and pulsed amperometric detection (HPAEC-PAD) revealed the exolytic nature of this enzyme. The Y. enterocolitica PL overproduced in E. coli was also partially purified and the M(r) and pI were estimated to be 55 kDa and 5.2, respectively. HPAEC-PAD analysis of the PL depolymerization products indicated the endolytic nature of this enzyme. Southern hybridization analyses revealed that pehY and pel genes of Y. enterocolitica are possibly encoded in the chromosome rather than in the plasmid. Purified exopolygalacturonase (over 10 activity units) was unable to macerate plant tissues.

Influence of soft rot bacteria on growth of Listeria monocytogenes on potato tuber slices

Growth of Listeria monocytogenes on potato tuber slices and its interaction with four representative species of soft rot bacteria (Pseudomonas fluorescens, P. viridiflava, Erwinia carotovora subsp. carotovora, and Xanthomonas campestris) were investigated. When potato tuber slices were inoculated with one of two L. monocytogenes strains (Scott A and ATCC 15313), an increase in numbers of 3 to 4 logs per gram of tissue was observed with samples that were stored at 20 degrees C for 6 days. However, an increase of about 2 logs was observed with samples that were stored at 8 degrees C for 12 days. When potato slices were simultaneously inoculated with L. monocytogenes and one of the four soft rot bacteria, the growth of L. monocytogenes was inhibited in the presence of P. fluorescens or P. viridiflava but was not significantly affected in the presence of E. carotovora or X. campestris. The antagonism of the two pseudomonads to L. monocytogenes was also observed in potato tuber extract and in culture media. Formation of inhibition zones was observed only in iron-deficient media but not in the medium supplemented with FeCl3. In addition, production of fluorescent siderophore (pyoverdin) by these two pseudomonads was demonstrated. L. monocytogenes was unable to colonize macerated plant tissue induced by soft-rotting bacteria 2 days before inoculation of the pathogen. These results indicate that growth of L. monocytogenes on potato tuber slices is differentially affected by soft rot bacteria and that antagonism of fluorescent pseudomonads to L. monocytogenes is possibly caused by the production of iron-chelating siderophore by these pseudomonads.

Cyclic AMP and cyclic GMP phosphodiesterase inhibition by an antiplatelet agent, 6-[(3-methylene-2-oxo-5-phenyl-5-tetrahydrofuranyl)methoxy)quinol inone (CCT-62)

The antiplatelet activity of (6-[(3-methylene-2-oxo-5-phenyl-5-tetrahydrofuranyl)methoxy]quinol inone) (CCT-62) was determined in vitro in rabbit platelets. CCT-62 inhibited rabbit platelet aggregation and ATP release caused by thrombin (0.1 U/ml), platelet-activating factor (2 ng/ml), collagen (10 microg/ml), arachidonic acid (100 microM), and 9,11-dideoxy-9alpha,11alpha-methanoepoxy prostaglandin F2alpha (1 microM) in a concentration-dependent manner. The IC50 values for platelet aggregation were 18.4 +/- 4.5, 10.1 +/- 1.6, 3.0 +/- 0.9, 1.5 +/- 0.3 and 1.0 +/- 0.3 microM, respectively. In addition, CCT-62 disaggregated the clumped platelets caused by these aggregation inducers. It also inhibited phosphoinositide breakdown and intracellular calcium elevation induced by the above platelet aggregation inducers. CCT-62 increased intracellular cyclic AMP and cyclic GMP levels in a concentration- and time-dependent manner. Furthermore, it potentiated cyclic AMP formation caused by prostaglandin E1 but not that caused by 3-isobutyl-1-methylxanthine. CCT-62 did not affect adenylate or guanylate cyclase but inhibited cyclic AMP- and cyclic GMP-phosphodiesterase activities. The antiplatelet effect of CCT-62 was reversed by a protein kinase A inhibitor, N-[2-(P-bromocinnamylamino)ethyl]-5-isoquinolinesulfonamide (H89). This data clearly indicated that CCT-62 is an inhibitor of phosphodiesterases and that its antiplatelet effect is mainly mediated by elevation of cyclic AMP levels.

Biochemical and genetic characterization of an extracellular protease from Pseudomonas fluorescens CY091

Pseudomonas fluorescens CY091 cultures produce an extracellular protease with an estimated molecular mass of 50 kDa. Production of this enzyme (designated AprX) was observed in media containing CaCl2 or SrCl2 but not in media containing ZnCl2, MgCl2, or MnCl2. The requirement of Ca2+ (or Sr2+) for enzyme production was concentration dependent, and the optimal concentration for production was determined to be 0.35 mM. Following ammonium sulfate precipitation and ion-exchange chromatography, the AprX in the culture supernatant was purified to near electrophoretic homogeneity. Over 20% of the enzyme activity was retained in the AprX sample which had been heated in boiling water for 10 min, indicating that the enzyme is highly resistant to heat inactivation. The enzyme activity was almost completely inhibited in the presence of 1 mM 1,10-phenanthroline, but only 30% of the activity was inhibited in the presence of 1 mM EGTA. The gene encoding AprX was cloned from the genome of P. fluorescens CY091 by isolating cosmid clones capable of restoring the protease production in a nonproteolytic mutant of strain CY091. The genomic region of strain CY091 containing the aprX gene was located within a 7.3-kb DNA fragment. Analysis of the complete nucleotide sequence of this 7.3-kb fragment revealed the presence of a cluster of genes required for the production of extracellular AprX in P. fluorescens and Escherichia coli. The AprX protein showed 50 to 60% identity in amino acid sequence to the related proteases produced by Pseudomonas aeruginosa and Erwinia chrysanthemi. Two conserved sequence domains possibly associated with Ca2+ and Zn2+ binding were identified. Immediately adjacent to the aprX structural gene, a gene (inh) encoding a putative protease inhibitor and three genes (aprD, aprE, and aprF), possibly required for the transport of AprX, were also identified. The organization of the gene cluster involved in the synthesis and secretion of AprX in P. fluorescens CY091 appears to be somewhat different from that previously demonstrated in P. aeruginosa and E. chrysanthemi.

Effect of PP1D-1, a synthetic antiplatelet compound, on rabbit platelets

The antiplatelet mechanism of a synthetic compound, 2-chloro-3-methoxycarbonylpropionamido-1,4-naphthoquinone (PP1D-1), was studied by employing washed rabbit platelets in vitro. PP1D-1 concentration-dependently inhibited thrombin (0.1 U/ml)-, platelet-activating factor (2 ng/ml)-, collagen (10 microg/ml)-, arachidonic acid (100 microM)- and U46619 (1 microM)-induced aggregation and ATP release in washed rabbit platelets. The IC50 values of PP1D-1 for aggregation induced by the above inducers are 17.9+/-1.7, 9.8+/-1.1, 3.9+/-0.4, 1.8+/-0.3 and 1.7+/-0.3 microM, respectively. PP1D-1 did not affect platelet thromboxane B2 or prostaglandin D2 formation induced by arachidonic acid, indicating that it did not affect cyclooxygenase and thromboxane synthase activities. PP1D-1 significantly inhibited the formation of inositol 1,4,5-trisphosphate caused by these five platelet stimulators. Moreover, PP1D-1 inhibited the increase in intracellular calcium concentration induced by these agents. On the contrary, PP1D-1 did not inhibit thapsigargin-elevated intracellular calcium concentration in indomethacin-pretreated platelets, indicating it did not influence the effect of thapsigargin. According to these data, PP1D-1 exerts antiplatelet effects mainly by inhibiting phosphoinositide turnover.

Bakkenolide G, a natural PAF-receptor antagonist

Because platelet-activating factor (PAF, 1-O-alkyl-2-acetyl-sn-glycero-3-phosphocholine) participates in many physiopathological responses, including inflammatory reaction, endotoxic shock, allergic diseases and platelet aggregation, PAF-receptor antagonists are important in the treatment of these diseases. A biologically active compound, bakkenolide G, extracted from the plant Petasites formosanus selectively and concentration-dependently inhibited PAF-induced platelet aggregation and ATP release. The IC50 of bakkenolide G for PAF (2 ng mL(-1))-induced platelet aggregation was 5.6 +/- 0.9 microM. Bakkenolide G also concentration-dependently inhibited PAF-induced intracellular signal transductions, including thromboxane B2 formation, and increased intra-cellular calcium concentration and phosphoinositide breakdown without affecting those caused by thrombin (0.1 units mL(-1)), collagen (10 microg mL(-1)), arachidonic acid (100 microM) and U46619 (1 microM). Bakkenolide G shifted the concentration-response curves of PAF-induced platelet aggregation parallel to the right; the Schild plot slope and the pA2 value were 1.31 +/- 0.31 and 6.21 +/- 0.75, respectively. Moreover, bakkenolide G concentration-dependently competed with [3H]PAF binding to platelets, with an IC50 value of 2.5 +/- 0.4 microM. These data strongly indicate that bakkenolide G is a specific PAF-receptor antagonist as an antiplatelet aggregatory agent.

Identification of gene loci controlling pectate lyase production and soft-rot pathogenicity in Pseudomonas marginalis

Pseudomonas marginalis is an important postharvest pathogen capable of causing soft rot in a wide variety of harvested fruits and vegetables. Following transposon mutagenesis, we isolated two groups of P. marginalis CY091 mutants deficient in production of pectate lyase (Pel) and soft-rot pathogenicity in plants. The first group, designated Pel-, was caused by the insertion of Tn5 into a pel structural gene, and the second group, designated LemA-, was caused by the insertion of Tn5 into a regulatory locus corresponding to the lemA gene previously identified in other Gram-negative bacteria. The LemA- mutants also exhibited alteration in colony morphology and showed deficiency in production of protease (Prt). A cosmid clone pCIC carrying the P. marginalis lemA gene was isolated and characterized. pCIC was capable of restoring Pel production and soft-rot pathogenicity in LemA- mutants of P. marginalis and Pseudomonas viridiflava, indicating that the function of lemA gene in these two pseudomonads was similar and interchangeable. Using MudI-mediated mutagenesis, we isolated a third group of P. marginalis mutants deficient in production of Pel, Prt, and soft-rot pathogenicity. Mutants in this group (designated GacA-1) contained an insertion of MudI in a locus corresponding to the gacA gene of P. viridiflava. Like LemA- mutants, GacA- mutants also exhibited alteration in colony morphology and showed deficiency in production of Pel and Prt. However, GacA- mutants produced much lower levels of levan and fluorescent pyoverdine siderophore than the wild type and LemA- mutants. These results provide the first genetic evidence that P. marginalis produces a single alkaline Pel for maceration of plant tissue and demonstrate that production of Pel, Prt, levan, and pyoverdin by this bacterium is mediated by the two-component lemA/gacA gene system.

Antiplatelet effect of demethyldiisoeugenol

A semisynthetic chemical compound, demethyldiisoeugenol, concentration dependently inhibited platelet aggregation and ATP release stimulated by thrombin (0.1 U/mL), platelet-activating factor (2 ng/mL), arachidonic acid (100 microM), collagen (10 micrograms/mL), and U46619 (1 microM) in rabbit washed platelets. The IC50 values of demethyldiisoeugenol on the inhibition of platelet aggregation induced by these five agonists were 157.3 +/- 22.3, 156.2 +/- 12.9, 53.6 +/- 4.7, 54.5 +/- 3.9, and 87.7 +/- 3.2 microM, respectively. Demethyldiisoeugenol also inhibited thromboxane B2 formation induced by thrombin, platelet-activating factor, arachidonic acid, and collagen, and prostaglandin D2 formation was induced by arachidonic acid. The rising intracellular Ca2+ concentration stimulated by these five platelet aggregation inducers was inhibited by demethyldiisoeugenol, while formation of inositol monophosphate was unaffected. Platelet cAMP and cGMP levels were unchanged by demethyldiisoeugenol. It is concluded that demethyldiisoeugenol may directly inhibit both intracellular calcium mobilization and cyclooxygenase activity in platelets.

The repB gene required for production of extracellular enzymes and fluorescent siderophores in Pseudomonas viridiflava is an analog of the gacA gene of Pseudomonas syringae

Two genes, designated repA and repB, are involved in the regulation of the synthesis of extracellular pectate lyase, protease, and alginate in Pseudomonas viridiflava. The repA gene has been shown to encode a protein highly homologous to several bacterial sensors in the two-component regulator family including the LemA of Pseudomonas syringae. In this study, the repB locus, initially identified in a 6.3-kb EcoRI genomic fragment of P. viridiflava, was further characterized. Results obtained from restriction mapping, deletion subclonings, and mini-Mu-LacZ fusions indicated that the repB gene was contained within a 0.8-kb HindIII-PstI region. Sequence analysis of this repB region revealed the presence of an open reading frame, which was predicted to encode a protein similar or identical to the gacA response regulator found in P. syringae and Pseudomonas fluorescens. The repB gene of P. viridiflava also regulated the production of fluorescent siderophores, in addition to the aforementioned extracellular enzymes and alginate. The repB or gacA homologs were detected in the genomes of nine other strains of P. viridiflava, P. fluorescens, and P. syringae included in the study. The data presented here and earlier indicate that the repA/repB gene regulatory system of P. viridiflava is analogous to the lemA/gacA system of P. syringae and P. fluorescens.

Gastric metaplasia of regenerating duodenal mucosa and deformity of duodenal bulb: a correlative study

The correlation between the presence and degree of gastric metaplasia of regenerating duodenal mucosa and the deformity of duodenal bulb was studied. Based on the endoscopically morphological patterns of bulb, the duodenal ulcers were divided into three types: type I, with a normal-shaped bulb; type II, with mildly deformed bulb; and type III, with a markedly deformed bulb. A total of 159 patients with active duodenal ulcers were scheduled to be treated with H2-receptor antagonists. Of these patients, 124 proved to have a healed duodenal ulcer 4 weeks after initial treatment upon follow-up endoscopic examinations. Two biopsies were taken from the centre of the ulcer scar when the ulcer was found to be healed for light microscopic study. Histologically, the degree of gastric metaplasia was divided into three grades: grades 0, 1 and 2. The results show that a healed duodenal ulcer with a normal-shaped bulb is not frequently accompanied by gastric metaplasia. However, a healed ulcer with a markedly deformed bulb has a high incidence and degree of gastric metaplasia, which may be easily colonized by Helicobacter pylori and thus develop an environment of easy recurrence. Therefore, a cycle of healing and recurrence may exist in patients with a duodenal ulcer and a markedly deformed bulb. Eradication of H. pylori may be the best way to break this cycle.

Cloning of a pectate lyase gene from Xanthomonas campestris pv. malvacearum and comparison of its sequence relationship with pel genes of soft-rot Erwinia and Pseudomonas

The cotton blight pathogen, Xanthomonas campestris pv. malvacearum strain B414, produces an extracellular pectate lyase (Pel) with an estimated M(r) of 41,000 and pI of 9.7. The gene coding for this enzyme initially identified in a 1.8-kb PstI genomic DNA fragment was cloned. The nucleotide sequences of this 1.8-kb fragment and two pel genes previously cloned from Pseudomonas fluorescens and P. viridiflava were determined. These pel genes encoded pre-Pel proteins consisting of 377 to 380 amino acids (a.a.). A signal peptide consisting of 26 to 29 a.a. was present at the amino-terminus of each pre-Pel. Multiple sequence analysis revealed that Pel proteins of non-Erwinia phytopathogens including Xanthomonas, Pseudomonas, and Bacillus constituted a distinct cluster, which showed 20 to 43% a.a. identity to the four established Pel families of Erwinia. Homologous pel sequences were detected in various pathovars or strains of X. campestris. All of these xanthomonads produced an alkaline Pel and were capable of causing soft-rot in potato tuber slices and green pepper fruits.

Marchantinquinone, isolated from Reboulia hemisphaerica, as inhibitor of lipid peroxidation and as free radical scavenger

The antioxidant effect of marchantinquinone was studied using various models. Marchantinquinone inhibited Fe(2+)-induced lipid peroxidation in rat brain homogenate in a concentration-dependent manner with an IC50 15.3 +/- 2.9 microM. Marchantinquinone was less effective than alpha-tocopherol and BHT in reducing the stable free radical diphenyl-2-picrylhydrazyl (DPPH). The IC0.200 were 37.5 +/- 2.5, 9.2 +/- 1.6 and 14.5 +/- 2.5 microM, respectively. Marchantinquinone also scavenged peroxyl radical derived from 2,2'-azobis(2-amidinopropane)dihydrochloride (AAPH) in aqueous system with a stoichiometric factor of 0.9 +/- 0.1. Furthermore, it prevented conjugated-diene formation and apolipoprotein B (apo B) oxidation of LDL. However, marchantinquinone did not chelate Fe2+ or possess superoxide anion and hydroxyl radical scavenging activity. It also did not scavenge 2,2'-azobis(2,4-dimethylvaleronitrile) (AMVN)-derived peroxyl radical in hexane. These results indicate that marchantinquinone may be an effective antioxidant and can protect rat brain homogenate and LDL against oxidation.

Antioxidant properties of demethyldiisoeugenol

The antioxidant properties of demethyldiisoeugenol were investigated in this study using various models. Demethyldiisoeugenol inhibited Fe(2+)-induced lipid peroxidation in rat brain homogenate in a concentration-dependent manner with an IC50 1.8 +/- 0.1 microM. Demethyldiisoeugenol was more effective than alpha-tocopherol and BHT in reducing the stable free radical diphenyl-2-picrylhydrazyl (DPPH). It also scavenged superoxide anion generated by xanthine/xanthine oxidase and peroxyl radical (ROO.) derived from 2,2'-azobis(2-amidinopropane)dihydrochloride (AAPH) in aqueous system with a stoichiometric factor of 1.3 +/- 0.2. Furthermore, it prevented conjugated-diene formation and apolipoprotein B (apo B) oxidation of LDL. However, demethyldiisoeugenol did not scavenge 2,2'-azobis(2,4-dimethylvaleronitrile) (AMVN)-derived peroxyl radical in hexane. It also did not chelate Fe2+, did not inhibit xanthine oxidase activity or possessed hydroxyl radical (.OH) scavenging activity. Experimental results indicate that demethyldiisoeugenol is a potentially effective antioxidant and can protect rat brain homogenate and LDL against oxidation.

Molecular characterization of two gene loci required for production of the key pathogenicity factor pectate lyase in Pseudomonas viridiflava

Four pleiotropic mutants of Pseudomonas viridiflava strain PJ-08-6A that were deficient in production of both pectate lyase (Pel) and protease (Prt) were isolated following transposon mutagenesis. Unlike secretion-defective (Out-) mutants, these four showed no accumulation of enzymes within the cells. Southern hybridization analysis revealed that each mutant had Tn5 inserted in one of two EcoRI genomic fragments. These EcoRI fragments (5.2- and 6.3-kb) appeared to contain two distinct gene loci, designated repA and repB, which were required for production of extracellular enzymes in this bacterium. Cosmid clones carrying the functional repA and repB DNA fragments were identified in a genomic library of strain PJ-08-6A. After analysis of repA+ plasmids by restriction mapping and marker-exchange mutagenesis, the repA gene was located in a joint region between the 1.8-kb EcoRI-HindIII and 2.8-kb EcoRI fragments cloned. Nucleotide sequence analysis of the repA region revealed the presence of an open reading frame consisting of 2,790 bases. The RepA protein predicted from the DNA sequence showed 93% similarity in amino acid sequence to the LemA protein of P. syringae pv. syringae, which was previously identified as a member of a two-component global regulatory system. A plasmid carrying the lemA gene of P. syringae pv. syringae was capable of complementing the RepA- mutation in P. viridiflava. The functions of the repA and lemA genes thus appear to be similar and interchangeable. Mutants of P. viridiflava strain SF312A deficient in production of Pel, Prt, and the exopolysaccharide alginate also were identified.(ABSTRACT TRUNCATED AT 250 WORDS)