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.

Purple urine bag syndrome with acidic urine

Purple discoloration of a urinary catheter bag is very rare. This phenomenon is known as the purple urine bag syndrome. It is associated with urinary tract infections occurring in catheterized patients, generally elderly females with significant co-morbidities and constipation. The urine is usually alkaline. We present a unique case of this rare and interesting phenomenon occurring in acidic urine and discuss the pathophysiology.

Laparoscopic adrenalectomy using needlescopic instruments for adrenal tumors less than 5cm in 112 cases

OBJECTIVE

To examine the safety and efficacy of laparoscopic adrenalectomy with needlescopic instruments for most adrenal tumors less than 5cm.

METHODS

Transperitoneal laparoscopic adrenalectomy with needlescopic instruments for 112 patients with presumptively benign adrenal tumors < 5cm were enrolled from July 2000 to February 2005. Operative time, blood loss, conversion and complication rates, and postoperative data were analyzed by appropriate statistical methods.

RESULTS

All 112 operations were completed without any mortality or reoperation. Mean operative time was 151min and mean blood loss was 30ml. Only one patient required a blood transfusion and application of a hand-assisted device. Conversion to conventional laparoscopic instruments was necessary in another five patients (4.5%). The operative time of the latter 100 cases (147+/-5.1min, mean+/-standard error of mean) was significantly shorter than that of the initial 12 cases (183+/-8.8min, p=0.001). Larger tumors, previous abdominal surgery, and pheochromocytoma group were independent risk factors of a longer operative time. Except for one leiomyosarcoma, all other tumors were benign adrenal pathologies (57 aldosterone-producing adenomas, 23 Cushing's adenomas, 12 pheochromocytomas, and 20 incidentalomas).

CONCLUSION

The safety and effectiveness of laparoscopic adrenalectomy employing needlescopic instruments for most adrenal tumors less than 5cm was feasible with acceptable operative time. Pheochromocytomas can also be managed with a longer operative time. Patients with previous upper midline or ipsilateral upper quadrant open surgery might not be suitable candidates for such a technique.

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.

Laparoscopic partial adrenalectomy for aldosterone-producing adenomas with needlescopic instruments

INTRODUCTION

Laparoscopic total adrenalectomy is the treatment of choice for aldosterone-producing adenomas (APAs). There have not been many reports of laparoscopic partial adrenalectomy, although this procedure offers benefits to patients with suspected bilateral APAs or an APA in a solitary adrenal gland. We describe the feasibility of a novel technique of laparoscopic partial adrenalectomy for APA solely using 2-mm working instruments and a 5 to 10-mm telescope.

TECHNICAL CONSIDERATIONS

Six unilateral and two bilateral partial adrenalectomies were performed laparoscopically. Only one umbilical 12-mm port for the telescope and two (for left adenomas) or three (for right adenomas) subcostal 2-mm working ports were used. Hemostasis and transection of adrenal tissues were performed using a 2-mm mini-bipolar coagulator and 2-mm scissors.

RESULTS

All laparoscopic operations were successfully performed using only 2-mm working instruments and a 5 or 10-mm 30 degree telescope with no intraoperative or postoperative complications. Blood loss was minimal, and the operative times were comparable to those of previous reports. All patients had low pain scores, required minimal amounts of narcotics postoperatively, and reported excellent cosmetic results for the wounds. The pathologic examinations confirmed complete excision of all adenomas with intact capsules. The plasma aldosterone concentrations and renin activities returned to normal ranges postoperatively in all patients. At a mean follow-up of 25 months (range 13 to 48), 7 (87.5%) were cured of their hypertension and 1 had the hypertensive medications significantly reduced.

CONCLUSIONS

Laparoscopic partial adrenalectomy for APAs using 2-mm working instruments and a 5 to 10-mm telescope is a safe and effective treatment alternative.

Laparoscopic adrenalectomy for potentially malignant adrenal tumors greater than 5 centimeters

PURPOSE

Laparoscopic adrenalectomy (LA) is controversial for large, potentially malignant tumors. We report a series of LA or hand-assisted LA for large (>5 cm) adrenal tumors.

PATIENTS AND METHODS

Among 210 LAs performed in 6 yr, 39 patients had potentially malignant tumors greater than 5 cm in diameter. Their perioperative and follow-up data were retrospectively analyzed.

RESULTS

All 39 patients had successful LAs without perioperative mortality, conversion to open surgery, or capsular disruption during dissection. The mean tumor size was 6.2 cm (range, 5-12 cm), operative time 207 min (115-315 min), and blood loss 75 ml (minimal-1400 ml). Complications included one intraoperative diaphragmatic perforation, three mild wound infections, and one pneumonia. Preoperatively there were 27 nonfunctioning tumors, seven pheochromocytomas, three cortisol-secreting tumors, and two virilizing tumors. Final pathology revealed eight malignant (four adrenocortical carcinomas and four metastatic carcinomas) and 31 benign tumors (14 cortical adenomas, eight pheochromocytomas, six myelolipomas, and three ganglioneuromas). Median follow-up was 39 months. Four patients (two adrenocortical carcinomas, one metastatic hepatoma, and one lymphoma) died 24, 10, 9, and 3 months after surgery, respectively. A hand-assisted device was used in 10 patients. Only the tumor size was larger and length of postoperative hospital stay longer for those in the hand-assisted group.

CONCLUSIONS

LA is a reasonable option for selected large adrenal tumors when complete resection is technically feasible and there is no evidence of local invasion. Hand-assisted LA is a good alternative to open conversion if a difficult dissection is encountered intraoperatively.

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.

Clipless needlescopic bilateral varix ligation

We report a novel technique of clipless needlescopic bilateral varix ligation and compare its results with the conventional laparoscopic approach. The positions of ports and surgical procedures were similar to those of the conventional 3-port laparoscopic technique, but all 5- and 10-mm trocars were replaced by 2-mm trocars. The internal spermatic veins proximal to the internal inguinal ring were isolated and coagulated for an adequate segment with a 2-mm bipolar electrocautery apparatus and then transected. The perioperative parameters of 25 patients operated on in this manner were compared with a historical cohort of 25 patients operated on using the conventional laparoscopic approach. Both groups of patients had uneventful surgery with no complications. The mean amount of analgesics used (1.25 vs 3.68 mg of morphine sulfate equivalent, P=.03), the maximal and mean postoperative pain scores (3.5 vs 5.6 and 2.5 vs 4.0, respectively, both P <.05), the postoperative hospital stay (0.5 vs 1.1 days, P=.03), and convalescence to normal activity (0.56 +/- 0.3 vs 1.64 +/- 0.4 weeks, P=.01) were all significantly decreased in the needlescopic group. We conclude that needlescopic bilateral varix ligation not only is feasible and safe but also provides the same therapeutic efficacy of a conventional laparoscopic approach; most importantly, it causes less pain and yields faster convalescence and excellent cosmetic results.

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.

Clipless laparoscopic adrenalectomy with needlescopic instruments

PURPOSE

We describe our experience with clipless laparoscopic adrenalectomy using needlescopic instruments. We compared the results with those of a contemporary series of conventional laparoscopic adrenalectomy.

MATERIALS AND METHODS

In 12 patients clipless laparoscopic adrenalectomy was performed with needlescopic instruments in an 8-month period. The technique included 2 or 3 subcostal 2 mm. ports and 1 umbilical 5/12 mm. port for the telescope and ultimate specimen extraction. Adrenal vessels were controlled by bipolar coagulation without endoscopic clips. Outcome data were retrospectively compared with those on 20 recent conventional laparoscopic adrenalectomies done at the same institution. The 2 types of laparoscopic adrenalectomy were performed transperitoneally.

RESULTS

Patients in the clipless group had a lower mean analgesic requirement (7.5 versus 15.3 mg. morphine sulfate equivalent, p = 0.02), lower mean pain and scar scores (3.1 versus 5.3 and 1.1 versus 4.2, respectively, p <0.05) and more rapid convalescence (1.6 versus 3.3 weeks, p <0.01) but longer operative time (183 versus 136 minutes, p = 0.04). Similar blood loss, time to oral intake and hospital stay were noted in the 2 groups. No major complications, open conversions or postoperative secondary bleeding occurred in either group. A 2 mm. port was converted to a 10 mm. port in only 1 case in the clipless group due to the inability to retract a bulky liver properly with a needlescopic instrument.

CONCLUSIONS

Clipless laparoscopic adrenalectomy with needlescopic instruments is feasible for most benign adrenal tumors. In addition to the benefits of conventional laparoscopic surgery, clipless needlescopic laparoscopic adrenalectomy further decreased postoperative pain, shortened convalescence and improved wound cosmesis.

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.