Altered expression of imprinted genes in patients with cytogenetically normal‑acute myeloid leukemia: Implications for leukemogenesis and survival outcomes

Genomic imprinting, an epigenetic mechanism that regulates gene expression from parental chromosomes, holds substantial relevance in multiple cancers, including hematopoietic malignancies. In the present study, the expression of a panel of 16 human imprinted genes in bone marrow samples from 64 patients newly diagnosed with cytogenetically normal-acute myeloid leukemia (CN-AML) were examined alongside peripheral blood samples from 85 healthy subjects. The validated findings of the present study revealed significant upregulation of seven genes [COPI coat complex subunit gamma 2 (COPG2), H19 imprinted maternally expressed transcript (H19), insulin like growth factor 2 (IGF2), PEG3 antisense RNA 1 (PEG3-AS1), DNA primase subunit 2 (PRIM2), solute carrier family 22 member 3 SLC22A3 and Zinc finger protein 215 (ZNF215)] in patients with CN-AML (P<0.001). Notably, the expression level of H19 exhibited an inverse association with the survival duration of the patients (P=0.018), establishing it as a predictive marker for two- and five-year survival in patients with CN-AML. Kaplan-Meier analysis demonstrated that patients with lower H19 expression had superior two- and five-year survival rates compared with those with higher H19 expression. The results of the present study highlighted the association between loss of imprinting and leukemogenesis in CN-AML, underscoring the significance of H19 imprinting loss as a prognostic indicator for unfavorable two- and five-year survival in CN-AML patients.

Clinical outcomes of endoscopic submucosal dissection for colorectal neoplasms: A single-center experience in Southern Taiwan

Background and aims

Endoscopic submucosal dissection (ESD) as an advanced endoscopic procedure can be considered for the removal of colorectal lesions with high suspicion of limited submucosal invasion or cannot be optimally removed by snare-based techniques. We aimed to analyze the clinical outcomes of ESD for colorectal neoplasms in our hospital.

Methods

We retrospectively enrolled 230 patients with 244 colorectal neoplasms who received ESD procedures from April 2012 to October 2020 at Kaohsiung Chang Gung Memorial Hospital. Clinicopathological data were collected by chart review. We also recorded ESD-related complications and clinical outcomes.

Results

The average age was 64 years old, with a mean follow-up time of 22.59 months. There was a loss of follow-up in 34 lesions. Most lesions were lateral spreading tumors of the non-granular type. The average ESD time was 51.9 minutes. Nine cases (3.7%) had procedure-related complications, including two intra-procedure perforations (0.8%) and seven delayed bleeding (2.9%) without procedure-related mortality. 241 lesions (98.8%) achieved en-bloc resection, while 207 lesions (84.8%) achieved R0 resection. Most lesions were tubulo-(villous) adenoma. Malignancy included 35 adenocarcinomas and 5 neuroendocrine tumors. No local recurrence was developed during follow-up. Multivariate analysis for long ESD time revealed significance in size ≥ 10 cm² and endoscopist’s experience < 3 years. Pre-ESD endoscopic ultrasound revealed good prediction in discrimination of mucosal (sensitivity: 0.90) and submucosal lesion (specificity: 0.67).

Conclusions

ESD for colorectal neoplasms is an effective and safe technique. Size ≥ 10 cm² and endoscopist’s experience < 3 years were significantly associated with long procedure time. Pre-ESD EUS provided a good prediction for colorectal neoplasms in invasion depth.

[Viral pathogenic spectrum analysis of severe acute respiratory infection cases in Luohe City, Henan province from 2017 to 2019]

Objective: The purpose of this study was to investigate the characteristics of viral pathogen spectrum and the epidemiological characteristics of each viral pathogen in hospitalized cases associated with severe acute respiratory infection (SARI) in Luohe City, Henan Province from 2017 to 2019. Methods: Based the SARI Case Surveillance Platform, SARI cases were collected in Central Hospital of Luohe City, Henan Province from November 2017 to February 2019. In the end, 783 SARI cases were included, whose throat swabs were taken within 24 h of admission, as well as their demographic characteristics, onset time, clinical characteristics and other information recorded. At the same time, viral identification was performed, and the age and time distribution of each virus were analyzed. Results: The age of 783 SARI cases shown as M (P₂₅, P₇₅) was 3 (1, 5) years old, ranging from 1 month to 95 years old. Children under 5 years old were the majority (71.01%). The males (61.81%) were more than females (38.18%). Among the 783 SARI cases, a total of 9 kind of viruses were identified with 64.88% (508/783) of the throat swabs tested positive for at least one virus. The positive rate of influenza virus and human respiratory syncytial virus were both 20.18% (158 cases), which was the highest among all the detected respiratory virus. The co-infection rate was 15.84% (124/783), among which double infection was the most common, accounting for 85.48% (106/124) of the co-infected cases. And human respiratory syncytial virus, human rhinovirus and influenza virus were the most common pathogen in co-infection cases. Moreover, the viral positive rate was 68.71% in children aged 5 years and 63.27% in people aged 60-95 years. Influenza and human respiratory syncytial virus dominated in winter and spring, while human parainfluenza virus was the main infection in summer. Conclusion: Influenza virus and human respiratory syncytial virus were the main viruses in throat swabs of SARI cases from 2017 to 2019 in Luohe City, Henan Province. There were differences in the age and seasonal epidemiological characteristics of each virus.

Clinicopathological features and outcome of esophageal neuroendocrine tumor: A retrospective multicenter survey by the digestive endoscopy society of Taiwan

BACKGROUND & AIMS

Esophageal neuroendocrine tumors (NET) are very rare and mostly carcinomic, carrying poor prognosis. There is still no guideline or consensus on the treatment for esophageal NET.

METHODS

Patients with histologically-proven esophageal neuroendocrine tumor were recruited from 9 hospitals in Taiwan between 2002 and 2017. Clinical, laboratory, radiological, endoscopic, pathological data, treatment strategies, follow-up periods, and survivals were collected retrospectively.

RESULTS

In total, 39 esophageal NET were analyzed and 38 were neuroendocrine carcinoma (NEC). Sixteen (41%) patients had mixed components with either adenocarcinoma (N = 9, 23%) or squamous-cell carcinoma (SCC) (N = 7, 18%). 64.1% of the patients experienced dysphagia and ulcerative mass was the most comment endoscopic finding. There was a higher proportion of drinkers (54.1%), betel chewers (21.6%) and smokers (64.9%) among the patients than in the general population in Taiwan. Five patients (12.8%) had been diagnosed with other cancers. Definite chemoradiotherapy (N = 14, 35.9%) and surgery (N = 7, 17.9%) were the major treatment. Patients with Ki-67% above the median level (50%) in the tumors tended to have worse survival (P = 0.06). However, presence of mixed component was not a significant survival predictor in our study (P = 0.56).

CONCLUSION

Mixed component of an esophageal NET is commonly observed. Staged workup and the principle of treatment can follow that for the common cancer type of esophagus. The risk factors and behaviors of esophageal NEC in Taiwan seem to be similar to that of esophageal SCC.

Effect of extracorporeal low-energy shock wave on diabetic gastroparesis in a rat model

BACKGROUND AND AIM

Delayed gastric emptying occurs in more than 50% of chronic diabetic patients, and this is associated with significant impairments in quality of life. Traditional therapy for delayed gastric emptying has focused on supportive treatment, and there is no significant effective therapy. The effect of low-energy shock wave on gastric motility is never studied. We investigated low-energy shock wave on gastric motility in a diabetic rat model.

METHODS

Twenty-eight male Wistar rats were studied and separated in three groups in randomized order as control, diabetic rats received shock wave, and diabetic rats received the sham procedure. Antral area and motility were recorded using the transabdominal ultrasound. Blood was taken for measurement of gastric motility peptides. Subjects were killed for immunohistochemical stain analysis of enteric plexus of the stomach.

RESULTS

We successfully induced 20 diabetic rats and set ultrasound for measuring rat gastric contract and emptying model and demonstrated that 6 weeks of low-energy shock wave could promote gastric contraction and emptying in diabetic rats. Moreover, we demonstrated that shock wave could increase defecation and feces and decrease serum cholesterol and triglycerol. However, no effect on glycohemoglobin and gastric motility peptides was recorded. In the immunohistochemical staining, shock wave increased expression of gastric myenteric neuron plexus.

CONCLUSION

Low-energy shock wave can increase gastric contraction and emptying by activating axonal regeneration and increasing myenteric plexus, but not related with motility peptides.

[Relationships between serum cystatin C, chemerin levels and subclinical atherosclerosis in type 2 diabetes mellitus patients]

Objective: To investigate the relationships between serum cystatin C (Cys C), chemerin levels and subclinical atherosclerosis in type 2 diabetes mellitus (T2DM) patients. Methods: A cross-sectional study was carried out between January 2016 and January 2018, and T2DM patients with carotid intima-media thickness (IMT) less than 1.1 mm were selected as subjects (100 males and 80 females, aged 40-60 years). The brachial-ankle pulse wave velocity (baPWV) ≥ 1 700 cm/s was set as the observation group (subclinical atherosclerosis) and baPWV<1 700 cm/s as the control group (non-subclinical atherosclerosis). Physical and blood examination were performed in both groups. Serum Cys C and chemerin levels were measured and their relationship with subclinical atherosclerosis was analyzed. Results: There was a statistically significant correlation between serum creatinine (r=0.167, P=0.011) and baPWV in the observation group, but not in the control group (r=0.105, P=0.070). Multiple linear regression analysis showed that age, duration of diabetes, serum creatinine, estimated glomerular filtration rate (eGFR), Cys C and chemerin were independently associated with baPWV, while high sensitive C reactive protein (hsCRP) and glycosylated hemoglobin (HbA1c) were not associated with baPWV. The elevation of serum Cys C (β'=0.393, P=0.003) and chemokine (β'=0.340, P=0.007) were correlative factors for atherosclerosis. Conclusion: The level of serum Cys C and chemerin is possibly related to the occurrence and development of subclinical atherosclerosis in T2DM patients.

Clinical features and outcomes of gastric neuroendocrine tumors after endoscopic diagnosis and treatment: A Digestive Endoscopy Society of Tawian (DEST)

Gastric neuroendocrine tumors (GNETs) are a heterogeneous group of neoplasm with varying biological characteristics. This study aimed to investigate the clinical features and outcomes of GNET patients after endoscopic diagnosis and treatment in a multicenter registry. Patients with GNETs confirmed histologically were recruited from 17 hospitals between January 2010 and April 2016 in Taiwan. Clinical, laboratory, radiological, endoscopic, pathological data, treatment strategies, follow-up periods, and survivals were collected retrospectively. Totally 187 (107 female, 80 male) patients were recruited. Mean ( ± standard deviation [SD]) age and size of tumors were 63.2-year-old ( ± 14.6) and 2.3-cm ( ± 3.0). World Health Organization (WHO) grading were 93 (49.7%) G1, 26 (13.9%) G2, 40 (21.4%) G3, and 28 (15.0%) unknown. G3 patients were older (mean ± SD, 71.6 ± 12.4 vs. 60.9 ± 14.3/56.7 ± 15.4 years), larger (6.1 ± 4.0 vs.1.2 ± 1.3/2.4 ± 2.5 cm), more distally located (35.0% vs. 7.6%/15.4%), lower proportion of superficial lesions (17.5% vs. 61.9%/53.8%) and higher rates of lymphovascular invasion (32.5% vs. 3.2%/7.7%) than G1/G2. There was no nodal or distant organ metastases despite different grading of lesions≦10 mm and those <20 mm limited to mucosa and submucosa layers. GNETs larger than 20 mm with G1, G2, and G3 had lymph node (LN) metastatic rates of 21.4%, 30.0%, and 59.3%, respectively. Survivals were different between grading for those >20 mm (log-rank test P = .02). Male gender (P = .01), deeper invasion (P = .0001), nodal (P < .0001), and distant organ metastases (P = .0001) were associated with worse outcome. In conclusion, treatment strategies for GNET should be decided by grading, size, invasiveness, and LN metastasis risk. Curative endoscopic resection is feasible for G1/2 lesions less than 20 mm and limited to mucosa/submucosa layers without lymphovascular invasion.

Endosonographic surveillance of 1-3 cm gastric submucosal tumors originating from muscularis propria

AIM

To observe the natural course of 1-3 cm gastric submucosal tumors originating from the muscularis propria (SMTMPs).

METHODS

By reviewing the computerized medical records over a period of 14 years (2000-2013), patients with 1-3 cm gastric SMTMPs who underwent at least two endoscopic ultrasound (EUS) examinations were enrolled. Tumor progression was defined as a ≥ 1.2 times enlargement in tumor diameter observed during EUS surveillance. All patients were divided into stationary and progressive subgroups and further analyzed. We also reviewed the patients in the progressive subgroup again in 2016.

RESULTS

A total of 88 patients were studied, including 25 in the progressive subgroup. The mean time of EUS surveillance was 24.6 mo in the stationary subgroup and 30.7 mo in the progressive subgroup. Risk factors for tumor progression included larger tumor size and irregular border. Initial tumor size > 14.0 mm may be considered a cut-off size for predicting tumor progression. Seventeen patients underwent surgery, of whom 13 had gastrointestinal stromal tumors (GISTs) and 4 had leiomyomas. Tumor progression was found only in patients with GISTs. All of the tumors exhibited benign behaviors without metastasis until 2016.

CONCLUSION

Most 1-3 cm gastric SMTMPs (71.6%) are indolent. Tumor progression was found only in GISTs, and it is a good predictor for differentiating GISTs from leiomyomas. Predictors of tumor progression include larger tumor size (> 14.0 mm) and irregular border.

A Randomized Control Trial Comparing 2 Levofloxacin-Containing Second-Line Therapies for Helicobacter pylori Eradication

Summary of Trial Design.Lengthy exposure to quinolone-containing triple therapy in Helicobacter pylori eradication leads to the development of drug resistance. Sequential therapy with a quinolone and metronidazole -containing regimen appears to be an effective treatment option. This randomized controlled trial aimed to compare the efficacy of 5-plus 5 days' levofloxacin and metronidazole-containing sequential therapy (EALM) with that of 10-day levofloxacin-containing triple therapy (EAL) in second-line H pylori eradication treatment.One hundred and sixty-four patients who had failed the H pylori eradication attempts using the standard triple therapy (proton pump inhibitor bid, clarithromycin 500 mg bid, amoxicillin 1 g bid × 7 days) were randomly assigned to either an EALM therapy group (n = 82; esomeprazole 40 mg bid and amoxicillin 1 g bid for 5 days, followed by esomeprazole 40 mg bid, levofloxacin 500 mg qd, and metronidazole 500 mg tid, for 5 days) or a 10-day EAL therapy group (n = 82; levofloxacin 500 mg qd, amoxicillin 1 g bid, and esomeprazole 40 mg bid). One patient was lost to follow-up in each group. Follow-up for H pylori status was performed 4 to 8 weeks later.Eradication rates for the EALM and EAL groups were 90.2% (74/82, 95% confidence interval [CI] = 83.7%-96.8%) and 80.5% (66/82, 95% CI = 71.7%-89.2%, P = 0.077) in the intention-to-treat analysis; and 91.4% (74/81, 95% CI = 85.1%-97.6%) and 81.5% (66/81, 95% CI = 72.8%-90.1%, P = 0.067) in the per-protocol analysis. The adverse events for the EALM and EAL groups were 23.5% versus 11.1%, P = 0.038 but were all very mild and were well tolerated except for 1 patient with poor compliance. The compliances were 98.8% and 100%, respectively, between the 2 groups. An antibiotic resistance to levofloxacin was the clinical factor influencing the efficacy of H. pylori eradication therapy in the EAL group, and dual resistance to levofloxacin and metronidazole in the EALM group.Levofloxacin and metronidazole-containing sequential therapy achieved a >90% eradication rate as a second-line H pylori therapy. Dual antibiotic resistance to levofloxacin and metronidazole was the clinical factor influencing the efficacy of H pylori eradication therapy in the sequential therapy (ClinicalTrials.gov number: NCT02596620).

Associated factors in Streptococcus bovis bacteremia and colorectal cancer

Reports suggest that between 25% and 80% of patients with Streptococcus bovis/gallolyticus bacteremia have concomitant colorectal tumors. This retrospective study was aimed to identify associations between clinical characteristics and a finding of colorectal neoplasm in patients with S. bovis bacteremia who had colonoscopy examination. We retrospectively reviewed the records of patients with S. bovis bacteremia from Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan, between January 2004 and January 2014. Clinical data including age, sex, comorbidities, blood culture, and colonoscopy findings were collected and their relationship to a finding of colorectal cancer was examined. A total of 107 patients with S. bovis bacteremia were identified, of whom 49 (72% male; age 65 ± 12 years) were investigated with colonoscopy; 15 of these patients (30.6%) had colorectal adenocarcinoma. Female sex (p = 0.014) and a history of noncolorectal malignancy (p = 0.004) were associated with a finding of colorectal adenocarcinoma. There were no associations with age, percentage of blood cultures, or the presence of diabetes mellitus, chronic liver disease, heart disease, or end-stage renal disease. Our results show that S. bovis bacteremia is associated with the presence of colorectal adenocarcinoma, especially in female patients, and concomitant existence of other malignancies.

Five-year sequential changes in secondary antibiotic resistance of Helicobacter pylori in Taiwan

AIM: To determine changes in the antibiotic resistance of Helicobacter pylori (H. pylori) in southern Taiwan after failure of first-line standard triple therapy.

METHODS: We analyzed 137 H. pylori-infected isolates from patients who experienced eradication failure after standard first-line triple therapy from January 2010 to December 2014. The H. pylori strains were tested for susceptibility to amoxicillin, clarithromycin, levofloxacin, metronidazole and tetracycline using the E-test method. The minimal inhibitory concentration (MIC) was determined by the agar dilution test. MIC values of ≥ 0.5, ≥ 1, ≥ 1, ≥ 4 and ≥ 8 mg/L were considered to be the resistance breakpoints for amoxicillin, clarithromycin, levofloxacin, tetracycline and metronidazole, respectively.

RESULTS: A high resistance rate was found for clarithromycin (65%-75%) and metronidazole (30%-40%) among patients who failed first-line standard therapy. The resistance levels to amoxicillin and tetracycline remained very low; however, levofloxacin resistance was as high as 37.5% in 2010 but did not increase any further during the past 5 years. The rates of resistance to these antibiotics did not show a statistically significant upward or downward trend.

CONCLUSION: Antibiotic resistance of H. pylori remains a problem for the effective eradication of this pathogen and its associated diseases in Taiwan. High clarithromycin resistance indicated that this antibiotic should not be prescribed as a second-line H. pylori eradication therapy. Moreover, levofloxacin-based second-line therapy should be used cautiously, and the local resistance rates should be carefully monitored.

Activated natural killer cells accelerate liver damage in patients with chronic hepatitis B virus infection

Emerging evidence indicates that natural killer (NK) cells may contribute to liver injury in patients with hepatitis B virus (HBV) infection. Because HBV infection progresses through various disease phases, the cytolytic profiles of peripheral and intrahepatic NK cells in HBV-infected patients remain to be defined. In this study, we comprehensively characterized intrahepatic and peripheral NK cells in a cohort of HBV-infected individuals, and investigated their impact on liver pathogenesis during chronic HBV infection. The study population included 34 immune-clearance (IC) patients, 36 immune-tolerant (IT) carriers and 10 healthy subjects. We found that the activity of peripheral NK cells from IC patients was functionally elevated compared to IT carriers and controls, and NK cell activation was indicated by an increased expression of CD69, CD107a, interferon (IFN)-γ and tumour necrosis factor (TNF)-α. Further analysis showed that the increased activity of both peripheral and hepatic NK cells was correlated positively with liver injury, which was assessed by serum alanine aminotransferase levels (ALT) and the liver histological activity index (HAI). Interestingly, the frequency of peripheral NK cells was reduced in IC patients (especially those with higher HAI scores of 3-4), but there was a concomitant increase in hepatic NK cells. The functionally activated NK cells are enriched preferentially in the livers of IC patients and skew towards cytolytic activity that accelerates liver injury in chronic hepatitis B (CHB) patients.

Deregulated expression of circadian clock genes in gastric cancer

BACKGROUND

Gastric cancer (GC), an aggressive malignant tumor of the alimentary tract, is a leading cause of cancer-related death. Circadian rhythm exhibits a 24-hour variation in physiological processes and behavior, such as hormone levels, metabolism, gene expression, sleep and wakefulness, and appetite. Disruption of circadian rhythm has been associated with various cancers, including chronic myeloid leukemia, head and neck squamous cell carcinoma, hepatocellular carcinoma, endometrial carcinoma, and breast cancer. However, the expression of circadian clock genes in GC remains unexplored.

METHODS

In this study, the expression profiles of eight circadian clock genes (PER1, PER2, PER3, CRY1, CRY2, CKIϵ, CLOCK, and BMAL1) of cancerous and noncancerous tissues from 29 GC patients were investigated using real-time quantitative reverse-transcriptase polymerase chain reaction and validated through immunohistochemical analysis.

RESULTS

We found that PER2 was significantly up-regulated in cancer tissues (p < 0.005). Up-regulated CRY1 expression was significantly correlated with more advanced stages (stage III and IV) (p < 0.05).

CONCLUSIONS

Our results suggest deregulated expressions of circadian clock genes exist in GC and circadian rhythm disturbance may be associated with the development of GC.

The effects of endoscopic-guided balloon dilations in esophageal and gastric strictures caused by corrosive injuries

Background

Esophageal stricture (ES) and gastric outlet obstruction (GOO) can occurred in patients injured by the ingestion of corrosive agents. These complications may occur concurrently but has not been reported in the literature. The aims of this study are to assess the effects and complications of endoscopic-guided balloon dilations (EBD) in patients with corrosive-induced upper gastrointestinal strictures, either ES or GOO alone and simultaneous occurrences of both (ES + GOO).

Methods

From July 2002 to December 2009, 36 patients with corrosive-induced upper gastrointestinal strictures in a tertiary hospital were recruited into this study. The patients were divided into three groups, ES group (n = 18), GOO (n = 7), and ES + GOO group (n = 11). All strictures were dilated under direct visualization by using through-the-scope balloon catheters to the end point of 15 mm. The end-point of treatment was successful ingestion of a solid or semisolid diet without additional dilation for more than 12 months.

Results

These 36 patients included 15 males and 21 females with average age of 47 years ranging from 25 to 79 years. The success rates for ES group is significantly better than GOO and ES + GOO group (83.3% vs. 57.1% vs. 36.4% p = 0.035). Less complications were observed in ES group than in GOO and ES + GOO group (16.7% vs. 42.9% vs. 36.4%, p = 0.041). GOO group needed more sessions of dilations in order to achieve success dilations than ES and GOO groups (13.7 ± 4.9 vs. 6.1 ± 4.7 vs. 5.5 ± 2.1, p = 0.011).

Conclusions

Corrosive injuries complicated with ES can be effectively and safely treated by EBD. However, the success rates declined significantly in patients with GOO with or without ES and amore complications occurred.

The efficacy of second-line anti-Helicobacter pylori therapy using an extended 14-day levofloxacin/amoxicillin/proton-pump inhibitor treatment--a pilot study

BACKGROUND

Large meta-analyses of second-line Helicobacter pylori eradication with fluoroquinolone triple therapy have shown that neither 7-day nor 10-day therapy provides 90% or better treatment success. Reports describing second-line H. pylori eradication using 14-day fluoroquinolone-containing triple therapy are few. Current study aimed to determine the efficacy of a 14-day levofloxacin/amoxicillin/proton-pump inhibitor regimen as second-line therapy and the clinical factors influencing the outcome.

MATERIALS AND METHODS

One-hundred and one patients who failed H. pylori eradication using the standard triple therapy for 7 days were randomly assigned to either a levofloxacin/amoxicillin/esomeprazole group (levofloxacin 500 mg once daily, amoxicillin 1 g twice daily, and esomeprazole 40 mg twice daily for 14 days) or a esomeprazole/metronidazole/bismuth salt/tetracycline group (esomeprazole 40 mg twice daily, metronidazole 250 mg four times daily, tripotassium dicitrate bismuthate 300 mg four times daily, and tetracycline 500 mg four times daily for 14 days). Follow-up to assess treatment response consisted of either endoscopy or a urea breath test, which were carried out 8 weeks later.

RESULTS

Eradication rates attained by levofloxacin/amoxicillin/esomeprazole and esomeprazole/metronidazole/bismuth salt/tetracycline treatments in the per-protocol analysis were 44/47 (93.6%; 95% CI = 86-99.8) and 43/47 (91.8%; 95% CI = 83.2-98.5). In the intention-to-treat analysis, these were 43/47 (86.3%; 95% CI = 76.5-96.1) in the LAE group (four lost to follow-up) and 43/50 (86%; 95% CI = 76-96) in the EMBT groups. The observed adverse events were 25.5% and 38.5% among the two groups. There was 100% drug compliance among the levofloxacin/amoxicillin/esomeprazole group. Levofloxacin-resistant strains occurred at a frequency of 32.3%. H. pylori eradication rates for the levofloxacin-susceptible strains and levofloxacin-resistant strains were 92% (11/12) and 33% (1/3) in the per-protocol analysis.

CONCLUSIONS

A 14-day levofloxacin/amoxicillin/esomeprazole triple therapy approach provides a >90% per-protocol report card with the caveat that this approach is markedly less effective in the presence of fluoroquinolone resistance. Levofloxacin-resistant strains are increasing in Taiwan.

Zoledronate inhibits phosphate and bone morphogenetic protein 2-induced extracellular calcification of vascular smooth muscle cells in vitro

The aim of this study was to explore the effects of the bisphosphonate zoledronate on calcification induced by inorganic phosphate (Pi) and/or bone morphogenetic protein 2 (BMP-2) and the underlying mechanisms. Primary vascular smooth muscle cells (VSMCs) from rats were treated with 3 mM Pi or 3 mM Pi/BMP-2, with and without addition of zoledronate; 1.4 mM Pi served as a control. Calcium deposits, expression of core binding factor α-1 (Cbfa-1), osteopontin (OPN), parathyroid pituitary-specific transcription factor (Pit)-1 and Pit-2, and Pi uptake of VSMCs was determined. The calcification of VSMCs induced by elevated Pi or Pi/BMP-2 was significantly inhibited by zoledronate. The expression of Cbfa-1, OPN and Pit-1 was increased significantly after treatment with an elevated level of Pi or Pi/BMP-2, and this expression was significantly suppressed by addition of zoledronate. Pi uptake of VSMCs increased following treatment with elevated Pi and significantly decreased by addition of zoledronate. These results indicated that zoledronate effectively inhibited calcification induced by Pi/BMP-2, and this may have been achieved by means of the downregulation of expression of calcification-related proteins and uptake of Pi.

Comparison of argon plasma coagulation in management of upper gastrointestinal angiodysplasia and gastric antral vascular ectasia hemorrhage

Background

Vascular ectasias, including gastric antral vascular ectasia (GAVE) and angiodysplasia, are increasingly recognized as important sources of gastrointestinal bleeding. This study investigated and compared the efficacies and outcomes of treatment of upper gastrointestinal (UGI) angiodysplasia and GAVE hemorrhage by endoscopic argon plasma coagulation (APC).

Methods

From January 2006 to December 2009, 46 patients diagnosed with upper GI bleeding caused by angiodysplasia or GAVE at a tertiary hospital were recruited into this study. They included 26 males and 20 females with an average age of 65.6 years (range, 45–90 years). All patients underwent APC for hemostasis during an endoscopic procedure. Parameters such as underlying co-morbidities, number of endoscopic treatment sessions, recurrent bleeding, and clinical outcomes during follow-up were analyzed.

Results

The 46 patients with UGI vascular ectasia hemorrhage included 27 patients with angiodysplasia and 19 with GAVE. The patients with angiodysplasia were older than those with GAVE (71.6 ± 10.2 years versus 61.8 ± 11.9 years, P = 0.005). More GAVE patients than angiodysplasia patients had co-existing liver cirrhosis (63.2% versus 25.9%, P = 0.012). The patients with GAVE had a higher rate of recurrent bleeding (78.9% versus 7.4%, P < 0.001) and required more treatment sessions to achieve complete hemostasis (2.4 ± 1.4 versus 1.1 ± 0.1, P < 0.001) than those with angiodysplasia. Univariate analysis demonstrated that age greater than 60 years (odds ratio (OR) = 8.929, P = 0.003), GAVE (OR = 0.021, P < 0.001), and previous radiation therapy (OR = 11.667, P = 0.032) were associated with higher rates of recurrent bleeding. Further multivariate analysis revealed that GAVE was the only independent risk factor for recurrent bleeding after APC treatment (OR = 0.027, P < 0.001).

Conclusion

Endoscopic hemostasis with APC is a safe treatment modality for both angiodysplasia and vascular ectasia bleeding. The efficacy of APC treatment is greater for angiodysplasia than for vascular ectasia bleeding. GAVE patients have a higher recurrent bleeding rate and may require multiple treatment sessions for sustained hemostasis.

Randomized comparison of two non-bismuth-containing second-line rescue therapies for Helicobacter pylori

BACKGROUND

 Classical second-line anti-Helicobacter pylori includes proton-pump inhibitor, tetracycline, metronidazole, and bismuth salts, but alternative therapies are required owing to the restricted availability of the latter. Levofloxacin-containing triple therapy is recommended but is expensive. Besides, quinolone resistance in an endemic tuberculosis infection area like Taiwan is concerned. The low in vitro antibiotic resistance to amoxicillin and tetracycline in Taiwanese H. pylori strains implies that in vivo esomeprazole/amoxicillin/tetracycline (EAT) second-line rescue therapy may be effective. This study compared the efficacy of esomeprazole/amoxicillin/levofloxacin (EAL) and EAT second-line eradication therapies and determines the clinical factors influencing the efficacy of salvage regimens.

MATERIALS AND METHODS

One hundred and twenty-eight patients who failed H. pylori eradication using the standard triple therapy for 7 days are randomly assigned to either EAL group (esomeprazole 40 mg twice daily, amoxicillin 1 g twice daily, and levofloxacin 500 mg once daily) for 7 days or EAT group (esomeprazole 40 mg twice daily, amoxicillin 1 g twice daily, tetracycline 500 mg four times daily) for 14 days. Follow-up endoscopy or urea breath test was performed 8 weeks later to assess treatment response.

RESULTS

The eradication rates of EAL and EAT groups were 78.1 versus 75.0%, p = .676 (in intention-to-treat analysis) and 80.3 versus 80%, p = .0964 (per-protocol analysis). Both groups exhibited similar drug compliance (95.3 vs 96.9%, p = .952) but more adverse events in the EAT group (6.3 vs 12.5%, p = .225).

CONCLUSIONS

Despite low in vitro drug resistances to amoxicillin and tetracycline, the efficacy of 14-day EAT regimens attained an unacceptable report card of 75% eradication rates in intention-to-treat analysis and was not even superior to the 7-day EAL regimen. Drug-drug interaction between combined antibiotics should be considered other than in vivo drug resistances.

Surveillance culture monitoring of double-balloon enteroscopy reprocessing with high-level disinfection

BACKGROUND

Inadequate reprocessing of double-balloon enteroscopy (DBE) or of endoscopic accessories may result in iatrogenic infections and present a risk to public health.

AIM

To use microbiological surveillance culture monitoring (SCM) to assess the adequacy of high-level disinfection (HLD) with standard reprocessing procedures of DBE.

MATERIALS AND METHODS

We performed a prospective study on cultures collected from DBEs that had been treated by HLD by an automated endoscope washing machine (AEWM) decontamination cycle. This study included 42 cases with 57 cultures, which were collected consecutively between October 2009 and December 2010. In 31 cases, 31 cultures were collected from oral route DBE (mean patient age, 68·9 years), and in 23 cases, 26 cultures were collected from anal route DBE (mean patient age, 67·9 years). The results obtained were compared with those of our previous study of SCM on gastroscopy (GS) and colonoscopy (CS). The samples were collected by flushing 50 mL sterile distilled water into the suction channel and collecting the flow-through in a sterile container. The samples were then incubated at 37 °C and examined for bacterial growth.

RESULTS

Before HLD, the positive culture rate was 83·9% (26/31) for the oral route DBE and 100% (26/26) for the anal route DBE (P = 0·0406). After HLD, the positive culture rate was 12·9% (4/31) for the oral route DBE and 19·2% (5/26) for the anal route DBE (P > 0·05). A linear trend relationship was found between positive SCM and the length and category of diagnostic instruments--GS, CS, oral route DBE and anal route DBE.

CONCLUSIONS

Surveillance culture monitoring is a useful method to assess the effectiveness of HLD reprocessing of DBE. Machine washing may not achieve complete disinfection. Using AEWM regularly is mandatory to minimize cross-contamination and to ensure quality assurance. Additional procedures are necessary to employ for the longer and anal route DBE.

Intravenous non-high-dose pantoprazole is equally effective as high-dose pantoprazole in preventing rebleeding among low risk patients with a bleeding peptic ulcer after initial endoscopic hemostasis

BACKGROUND

Many studies have shown that high-dose proton-pumps inhibitors (PPI) do not further reduce the rate of rebleeding compared to non-high-dose PPIs but we do not know whether intravenous non-high-dose PPIs reduce rebleeding rates among patients at low risk (Rockall score < 6) or among those at high risk, both compared to high-dose PPIs. This retrospective case-controlled study aimed to identify the subgroups of these patients that might benefit from treatment with non-high-dose PPIs.

METHODS

Subjects who received high dose and non-high-dose pantoprazole for confirmed acute PU bleeding at a tertiary referral hospital were enrolled (n = 413). They were divided into sustained hemostasis (n = 324) and rebleeding groups (n = 89). The greedy method was applied to allow treatment-control random matching (1:1). Patients were randomly selected from the non-high-dose and high-dose PPI groups who had a high risk peptic ulcer bleeding (n = 104 in each group), and these were then subdivided to two subgroups (Rockall score ≥ 6 vs. < 6, n = 77 vs. 27).

RESULTS

An initial low hemoglobin level, serum creatinine level, and Rockall score were independent factors associated with rebleeding. After case-control matching, the significant variables between the non-high-dose and high-dose PPI groups for a Rockall score ≥ 6 were the rebleeding rate, and the amount of blood transfused. Case-controlled matching for the subgroup with a Rockall score < 6 showed that the rebleeding rate was similar for both groups (11.1% in each group).

CONCLUSION

Intravenous non-high-dose pantoprazole is equally effective as high-dose pantoprazole when treating low risk patients with a Rockall sore were < 6 who have bleeding ulcers and high-risk stigmata after endoscopic hemostasis.

Is a biopsy necessary for colon polyps suitable for polypectomy when performing a colonoscopy?

BACKGROUND

The incidence of colorectal cancer is increasing in Taiwan. Adenomatous polyps are known to be precancerous lesions and need to be removed. New techniques like chromendoscopy, magnifying endoscopy, narrow band imaging and magnifying endoscopy with flexible spectral imaging color enhancement may improve the accuracy of identifying precancerous polyps but are not widely available in the real world. This study analyzed the conventional biopsy method in diagnosing early colon cancer and the necessity for subsequent surgery after polypectomy.

METHODS

From January 2002 to December 2007, 1027 adenomatous polypoid specimens taken from 720 patients who received polypectomy by conventional white light colonoscopy were studied. The pathologic reports of 26 specimens of early cancer or high grade dysplasia from 25 patients were analyzed. Protruding polyps were classified as pedunculated (o-Ip), subpedunculated (o-Isp) and sessile (o-Is).

RESULTS

Fourteen of the 26 specimens were type o-Ip, 10 were type o-Isp, and 2 were type o-Is. The pathologic reports were high grade dysplasia (n = 5), mucosal adenocarcinoma (n = 18) and submucosal adenocarcinoma (n = 3). Among these, 7 lesions from 7 patients received a randomized biopsy instead of immediate polypectomy. Adenoma was reported in 6 of them with only one malignancy detected (false negative rate: 86%). Eight patients received surgery. The mean follow-up period for these patients was 17 months, and none of them had recurrences.

CONCLUSIONS

The randomized biopsy method for adenomatous polyps has a high false negative rate for early colon cancer and high grade dysplasia and is therefore not necessary in cases of protruding type polyps which can be removed by polypectomy. An adequate direct polypectomy may completely remove the protruding type of early colon cancer.

Effect of ginger on gastric motility and symptoms of functional dyspepsia

AIM

To evaluate the effects of ginger on gastric motility and emptying, abdominal symptoms, and hormones that influence motility in dyspepsia.

METHODS

Eleven patients with functional dyspepsia were studied twice in a randomized double-blind manner. After an 8-h fast, the patients ingested three capsules that contained ginger (total 1.2 g) or placebo, followed after 1 h by 500 mL low-nutrient soup. Antral area, fundus area and diameter, and the frequency of antral contractions were measured using ultrasound at frequent intervals, and the gastric half-emptying time was calculated from the change in antral area. Gastrointestinal sensations and appetite were scored using visual analog questionnaires, and blood was taken for measurement of plasma glucagon-like peptide-1 (GLP-1), motilin and ghrelin concentrations, at intervals throughout the study.

RESULTS

Gastric emptying was more rapid after ginger than placebo [median (range) half-emptying time 12.3 (8.5-17.0) min after ginger, 16.1 (8.3-22.6) min after placebo, P≤0.05]. There was a trend for more antral contractions (P=0.06), but fundus dimensions and gastrointestinal symptoms did not differ, nor did serum concentrations of GLP-1, motilin and ghrelin.

CONCLUSION

Ginger stimulated gastric emptying and antral contractions in patients with functional dyspepsia, but had no impact on gastrointestinal symptoms or gut peptides.

Predictors of rebleeding after initial hemostasis with epinephrine injection in high-risk ulcers

AIM: To identify the predictors of rebleeding after initial hemostasis with epinephrine injection (EI) in patients with high-risk ulcers.

METHODS: Recent studies have revealed that endoscopic thermocoagulation, or clips alone or combined with EI are superior to EI alone to arrest ulcer bleeding. However, the reality is that EI monotherapy is still common in clinical practice. From October 2006 to April 2008, high-risk ulcer patients in whom hemorrhage was stopped after EI monotherapy were studied using clinical, laboratory and endoscopic variables. The patients were divided into 2 groups: sustained hemostasis and rebleeding.

RESULTS: A total of 175 patients (144, sustained hemostasis; 31, rebleeding) were enrolled. Univariate analysis revealed that older age (≥ 60 years), advanced American Society of Anesthesiology (ASA) status (category III, IV and V), shock, severe anemia (hemoglobin < 80 g/L), EI dose ≥ 12 mL and severe bleeding signs (SBS) including hematemesis or hematochezia were the factors which predicted rebleeding. However, only older age, severe anemia, high EI dose and SBS were independent predictors. Among 31 rebleeding patients, 10 (32.2%) underwent surgical hemostasis, 15 (48.4%) suffered from delayed hemostasis causing major complications and 13 (41.9%) died of these complications.

CONCLUSION: Endoscopic EI monotherapy in patients with high-risk ulcers should be avoided. Initial hemostasis with thermocoagulation, clips or additional hemostasis after EI is mandatory for such patients to ensure better hemostatic status and to prevent subsequent rebleeding, surgery, morbidity and mortality.

Gastric metastasis of hepatocellular carcinoma via a possible existing retrograde hematogenous pathway

BACKGROUND AND AIM

Hepatocellular carcinoma (HCC) tends to metastasize to extrahepatic organs. Stomach involvement has been seldom reported and has always been considered as direct invasion. This study aims to propose a possible existing pathway for the hematogenous metastasis of HCC to the stomach.

METHODS

Only seven cases with stomach involvement were found from 8267 HCC patients registered at our hospital between 2000 and 2007. Their laboratory data, the findings of computed tomography and upper endoscopy, therapeutic procedures, such as esophageal variceal banding ligation (EVL), and transhepatic arterial embolization (TAE) were further studied.

RESULTS

All seven patients were male. Liver cirrhosis was found in six patients (6/7 = 85.7%), HCC with portal vein thrombosis (PVT) in six patients (6/7 = 85.7%), splenomegaly in five patients (5/7 = 71.4%) and esophageal varices in five patients (5/7 = 71.4%). Six patients underwent TAE and one patient underwent EVL before the development of HCC in the stomach. Four patients had HCC at the cardia, one patient at the anterior wall of the high body and two patients at the greater curvature of the high body, far away from the original HCC. Six patients eventually developed distant metastasis. HCC with gastric metastasis developed 53-126 days after TAE in five patients and 74 days after EVL in one patient.

CONCLUSIONS

When cirrhotic patients with portal hypertension have HCC with PVT, a hematogenous pathway can exist for gastric metastasis of tumor thrombi involving hepatofugal flow to the stomach after TAE or EVL apart from the major pathway of direct invasion.

Abdominal tuberculosis: analysis of clinical features and outcome of adult patients in southern Taiwan

BACKGROUND

Abdominal tuberculosis remains a serious health threat. This retrospective report aimed to analyze patients after the development of the tuberculosis control program by the Center of Disease Control (Taiwan) in January 2000. The study was conducted at the Chang Gung Memorial Hospital-Kaohsiung, Taiwan.

METHODS

Between January 2000 and December 2006, we evaluated 14 adult patients with abdominal tuberculosis by reviewing their clinical information, therapeutic methods and outcomes. Diagnosis of abdominal tuberculosis was made based on clinical features of abdominal infection with microbiological results from culture, acid-fast bacilli stain and polymerase chain reaction for Mycobacterium tuberculosis and/or histopathological confirmation from biopsy and ascites.

RESULTS

Tuberculous peritonitis and intestinal tuberculosis were the most common type of infections followed by hepatic tuberculosis, and intra-abdominal tuberculoma. 35.7% of these patients had the coexistence of extra-abdominal infection. The most common clinical symptoms and signs were abdominal pain, abdominal distension, ascites and body weight loss. Fever was found in 35.7% of patients and peritoneal signs were noted in 7.1%. Immunocompromised states and old age are relevant to adult abdominal tuberculosis. Overall, patients were diagnosed by bacteriology (35.7%), biopsy materials from laparotomy (42.8%), liver biopsy (14.3%), and biopsy materials from colonoscopy (7.2%). Patients were cured after taking antituberculous drugs for at least 6 months without relapse during regular follow-up for at least 2 years. However, three patients died of sepsis and decompensated liver cirrhosis during treatment.

CONCLUSION

Extra vigilance in dealing with patients who present with unexplained abdominal conditions is the key to the diagnosis of abdominal tuberculosis. Early diagnosis, early antituberculous therapy and surgical treatment of the associated complications are essential for the survival of the patient.

Sonographic findings in esophageal achalasia

BACKGROUND

There are only three reports using conventional sonography to detect the gastroesophageal junction through the left lobe liver window in patients with achalasia, and the results were inconsistent. This study further characterizes the sonographic features of achalasia and compares them to characteristics of subjects with gastroesophageal malignancies.

METHODS

Conventional sonography was performed in 21 patients with achalasia (mean age 49.0 years, 11 male and 10 female, group A); 15 patients with malignancies at the gastroesophageal junction (n=10) and cardiac of the stomach (n=5) (mean age 55.3 years, 11 male and 4 female, group B); and 30 subjects with functional dyspepsia (mean age: 38.3 years, 15 male and 15 female, control group C).

RESULTS

The median esophageal wall thicknesses were 5.1+/-2.3 mm (group A), 19.5+/-7.8 mm (group B), and 3.3+/-1.2 mm (group C). However, there was overlap in the esophageal wall thickness in groups A and C. Sonographic features in group A were regular hypoechoic thickening of the wall at the gastroesophageal junction; in group B, we found irregular hypoechoic thickening of the wall. Control subjects had a regular hypoechoic gastroesophageal wall. Dilated lumens of the distal esophagus were seen in all achalasia patients.

CONCLUSION

Although conventional sonography is not a diagnostic tool for achalasia, it provides interesting sonographic information. It cannot reveal each layer of the wall of the lumen as endoscopic ultrasound does, but it may tentatively differentiate achalasia from malignancies and assists clinicians when endoscopic ultrasound is not available.

Short report: Abnormal liver function in scrub typhus

Scrub typhus is one kind of rickettsial disease and may cause fever, cough, and skin rashes in infected humans. Regarding liver involvement, it was uncommon to be reported in previous medical literature from Western countries. This study observes the relationship between scrub typhus and liver function. From January 1998 to August 2003 in Kaohsiung Chang Gung Memorial Hospital in Taiwan, we observed 30 patients with scrub typhus, and 29 of them had liver function abnormality. In these patients, we found 89.3% with elevated aspartate aminotransferase (AST) levels, 91.7% with elevated alanine aminotransferase (ALT) levels, 84.2% with elevated alkaline phosphatase (ALP) levels, and 38.5% with elevated total bilirubin levels. In our study, there is a close relationship between scrub typhus and impaired liver function tests. Therefore, if patients are found with fever of unknown origin and abnormal liver function, we should take scrub typhus into consideration.

Induction of oxidative DNA damage in human foreskin fibroblast Hs68 cells by oxidized beta-Carotene and lycopene

Two recent clinical trials suggest that beta-carotene may be harmful to smokers. In this study we examined the hypothesis that beta-carotene may become toxic when degradation occurs. beta-Carotene (BC) and lycopene (LP) with or without prior heat treatment (60 degrees C for 1 h in open air) were incubated at 20 and 40 microM with calf thymus DNA or human fibroblasts Hs68 cells. The heat treatment resulted in ca. 80% and 35% bleaching of BC and LP, respectively. When Hs68 cells were incubated with the oxidized beta-carotene (OBC) or oxidized lycopene (OLP) at 37 degrees C for 20 h, cell viability was significantly and dose-dependently decreased whereas cell viability was not affected by BC or LP. Cell death, which was already evident at 4 h after incubation with OBC or OLP, was possibly attributable to apoptosis, as shown by the increased histone-associated DNA fragmentation. However, cell lysis, measured as release of lactate dehydrogenase, also occurred at 4 h after incubation with OBC and OLP, although the extent was relatively small and was greater for OLP than for OBC. When calf thymus DNA was incubated with OBC or OLP at 37 degrees C for 20 h, the 8-hydroxy-2-deoxyguanosine (8-OH-dG) level was significantly and dose-dependently increased by OLP whereas the increase by OBC was only significant at 40 microM. When Hs68 cells were incubated with OBC and OLP for 20 h, both compounds increased the 8-OH-dG level, but the effect was only significant for 40 microM OLP. Comet (single-cell gel electrophoresis) assay of DNA damage in Hs68 cells was determined at 2 h after incubation with OBC or OLP because of its high sensitivity. Both OBC and OLP significantly and dose-dependently increased DNA breakage while BC and LP had no effect. Inclusion of BHT during incubation of cells with 40 microM OBC or OLP partially inhibited (ca. 40%, p < .05) the extent of comet formation. Intriguingly, OBC and OLP neither induce lipid peroxidation in Hs68 cells (measured as thiobarbituric acid-reactive substances released into the medium) nor increased the intracellular level of reactive oxygen species. Although it is presently unclear about what degradation products are formed, this study has demonstrated that, when oxidized, BC and LP lead to oxidative damage to both purified DNA and cellular DNA. The results suggest that such damage may contribute to the adverse effects of beta-carotene reported in recent clinical studies and caution that it is important to prevent oxidation of BC and LP for human uses such as in supplemental studies.

DHEA inhibits cell growth and induces apoptosis in BV-2 cells and the effects are inversely associated with glucose concentration in the medium

Dehydroepiandrosterone (DHEA), a major steroid secreted by the adrenal gland which decreases with age after adolescence, is available as a nutritional supplement. DHEA is known to have antiproliferative effects but the mechanism is unclear. In this study using BV-2 cells, a murine microglial cell line, we investigated the effect of DHEA on cell viability and the interaction between DHEA and glucose concentrations in the medium. We showed that DHEA inhibited cell viability and G6PD activity in a dose-dependent manner and that the effect of DHEA on cell viability was inversely associated with glucose concentrations in the medium, i.e. lowered glucose strongly enhanced the inhibition of cell viability by DHEA. DHEA inhibited cell growth by causing cell cycle arrest primarily in the G0--G1 phase, and the effect was more pronounced at zero glucose (no glucose added, G0) than high glucose (4.5 mg/ml of the medium, G4.5). Glucose deprivation also enhanced apoptosis induced by DHEA. At G4.5, DHEA did not induce formation of DNA ladder until it reached 200 microM. However, at G0, 100 microM DHEA was able to induce apoptosis, as evidenced by the formation of DNA ladder, elevation of histone-associated DNA fragmentation and increase in cells positively stained with annexin V-FITC and annexin V-FITC/propidium iodide. The interactions between DHEA and glucose support the contention that DHEA exerts its antiproliferative effects through alteration of glucose metabolism, possibly by inhibition of G6PD activity leading to decreased supply of ribose-5-phosphate for synthesis of DNA and RNA. Although DHEA is only antiproliferative at pharmacological levels, our results indicate that its antiproliferative effect can be enhanced by limiting the supply of glucose such as by energy restriction. In addition, the present study shows that glucose concentration is an important factor to consider when studying the antiproliferative and toxicological effects of DHEA.

Total plasma malondialdehyde levels in 16 Taiwanese college students determined by various thiobarbituric acid tests and an improved high-performance liquid chromatography-based method

OBJECTIVES

In determining the plasma malondialdehyde MDA levels in some Taiwanese college students, we found rather different results by using different thiobarbituric acid TBA tests, even by the high-performance liquid chromatography HPLC-based methods. Here, we re-evaluated four commonly used TBA tests and improved the HPLC-based test.

DESIGN AND METHODS

We used the blood plasma of 16 college volunteers to determine plasma MDA by using four methods: a spectrophotometric measurement of thiobarbituric acid-reactive substances (TBARS) in the TCA-supernatant of plasma (Method A); a fluorescence measurement of plasma lipid peroxides (Method B); and two different HPLC-based measurements of MDA with either 532-nm measurement (Method C, HPLC/532 nm) or fluorescence measurement (Method D, HPLC/fluor.).

RESULTS

The levels of MDA or TBA reactive substances obtained from the four methods differed substantially (0.39 +/- 0.15; 2.14 +/- 0.73; 0.75 +/- 0.22; and 0.38 +/- 0.15 microM for Methods A, B, C, and D, respectively). The results were positively correlated between Methods A and B (r = 0.740, p < 0.02) and between Methods C and D (r = 0.516, p < 0.05). However, results were negatively correlated between Methods B and D (r = -0.548, p < 0.05). Because most plasma MDA is bound to proteins, we modified the HPLC-based methods (C and D) by adding an alkaline hydrolysis step, and the plasma TBA-MDA adduct detected by HPLC/532 nm was referred to as total MDA. RESULTS show that alkaline hydrolysis was a critical step for measurement of total MDA in plasma because this treatment led to release of MDA from plasma proteins. We also adapted the potassium iodide (KI) treatment of plasma from Method D to reduce lipid hydroperoxides. Our modified method gave a total MDA level in the 16 volunteers of approximately 1.5 microM, which was equal to protein-bound MDA plus free MDA. This total MDA level was positively (p < 0.05) correlated with the level of TBA reactive substances obtained from Methods C (r = 0.63, p < 0.05) and D (r = 0.48, p < 0.07), but was not correlated with those from Methods A and B. The recovery (84 approximately 105%), precision (within-assay coefficient of variation: 2.4%, between-assay coefficient of variation: 4 approximately 8%) and sensitivity of the modified procedure were comparable to other HPLC-based methods.

CONCLUSION

By using a validated modification of HPLC-based TBA method, the total plasma MDA in 16 Taiwanese college students was found to be 1.54 microM, which was relatively high compared to those obtained by other HPLC-based method, primarily due to the release of protein-bound MDA by alkaline hydrolysis. This level equaled the sum of protein-bound MDA and free MDA in plasma, confirming that this level represents total plasma MDA.

Use of rat liver slices for the study of oxidative DNA damage in comparison with isolated rat liver nuclei and HepG2 human hepatoma cells

Tissue slices are a useful biological system for lipid peroxidation studies but their use for DNA damage studies is not well characterized. Hence, the present study investigates DNA damage in rat liver slices, in comparison with isolated rat liver nuclei and HepG2 human hepatoma cells, incubated with ferric nitrilotriacetate (Fe(III)-NTA), bromotrichloromethane (BrCCl(3)), bromobenzene (BrB) or 2-nitropropane (2-NP) at 37 degrees C for 2 hr. DNA damage was measured in slices, cells or nuclei after centrifugation as formation of as 8-hydroxy-2'-deoxyguanosine (8-OH-dGu) and loss of double-stranded (dsDNA) due to strand breakage using a fluorometric analysis of DNA unwinding (FADU). Lipid peroxidation was measured as thiobarbituric acid-reactive substances (TBARS) released into the medium. The results show that in liver slices and isolated nuclei, Fe/NTA (1 mM/4 mM) induced high levels of TBARS but low levels of 8-OH-dGu, whereas the oxidant induced low levels of TBARS and no formation of 8-OH-dGu in HepG2 cells. In all three systems, inclusion of ascorbate caused dose-dependent formation of 8-OH-dGu, and the levels were similar between liver slices and HepG2 cells but were far higher in isolated nuclei. In liver slices the FADU assay was not applicable due to limited solubilization of DNA from the slice, whereas the assay detected significant loss of dsDNA in HepG2 cells and slight loss in isolated nuclei induced by Fe/NTA with or without ascorbate. Liver slices incubated with 1 mm BrCCl(3), BrB or 2-NP had elevated TBARS but had little or no formation of 8-OH-dGu; none of these oxidants induced lipid peroxidation or DNA damage in HepG2 cells. When liver slices obtained from rats injected with diethylmaleate (to deplete GSH) were incubated with BrCCl(3), BrB or 2-NP, levels of TBARS and 8-OH-dGu increased markedly. Similarly, HepG2 cells with decreased GSH showed marked elevation of TBARS and loss of dsDNA induced by these oxidants, although no formation of 8-OH-dGu was detected. The present study demonstrates the usefulness and limitations of liver slices for DNA damage studies and the importance of cellular GSH in the protection of DNA against environmental toxicants.

Toxicological and antioxidant effects of short-term dehydroepiandrosterone injection in young rats fed diets deficient or adequate in vitamin E

This study examined the in vivo antioxidant and/or prooxidant effect of short-term dehydroepiandrosterone (DHEA) injection and the effect of dietary vitamin E. Male Sprague-Dawley rats (4 wk old) were fed vitamin E-deficient or vitamin E-adequate (30 mg DL-alpha-tocopheryl acetate/kg) diet for 4 weeks followed by intraperitoneal injection of DHEA for 1 week. The results showed that DHEA injection caused a dose-dependent decrease in body weight, and this effect was more pronounced in vitamin E-deficient rats. In contrast, DHEA injection significantly increased liver, kidney and adrenal weights. Hepatic vitamin E content was significantly lowered by vitamin E deficiency, which led to significantly increased ex vivo and iron-induced lipid peroxidation. DHEA injection did not affect hepatic vitamin E content but significantly decreased ex vivo and iron-induced lipid peroxidation in vitamin E-deficient rats. Hepatic total sulfhydryl (SH) groups and non-protein SH contents were not affected by vitamin E but were significantly increased by DHEA injection, which at 100 mg/kg was not more effective than at 50 mg/kg. Hepatic glutathione S-transferase (GST) activity was significantly decreased by DHEA, but vitamin E alleviated such a decrease. DHEA injection significantly increased hepatic glucose 6-phosphate dehydrogenase (G6PD) activity, and the effect was dose dependent in vitamin E-deficient rats. Thus, DHEA may compensate for vitamin E deficiency in vivo, and this effect is masked when dietary vitamin E is adequate. The antioxidant effect of DHEA is accompanied by decreased body weights, enlarged (fat-laden) tissues and altered activities of hepatic GST and G6PD.

Elevated lipid peroxidation and disturbed antioxidant enzyme activities in plasma and erythrocytes of patients with uterine cervicitis and myoma

OBJECTIVES

We investigated whether oxidative stress is associated with human uterine cervicitis and uterine myoma.

DESIGN AND METHODS

We measured lipid peroxidation and antioxidant enzymes in plasma and erythrocytes of cervicitis patients and myoma patients in comparison with matched controls. Thiobarbituric acid-reactive substances (TBARS), a measure of lipid peroxidation, were determined in plasma; glutathione peroxidase (GSHPx) and catalase in erythrocytes; and superoxide dismutase (SOD) in both plasma and erythrocytes.

RESULTS

We showed that plasma TBARS were significantly higher (p < 0.05) in both cervicitis patients and myoma patients than in controls. Plasma TBARS were significantly (and negatively) correlated with plasma and erythrocyte T-SOD activities in cervicitis patients only. Plasma T-SOD activity was significantly lower in both groups of patients than in controls whereas erythrocyte T-SOD activity was only significantly lower in myoma patients. The lowered plasma T-SOD activity in the cervicitis patients was attributed to decreased Mn-SOD activity whereas the lowered plasma T-SOD activity in myoma patients was attributed to decreased activities of both Cu,Zn-SOD and Mn-SOD. Erythrocyte GSHPx activity was 14% higher (p < 0.05) in cervicitis patients and 11% lower (p > 0.05) in myoma patients than in controls; catalase activity was 10% higher (p > 0.05) in cervicitis patients and 13% lower (p > 0.05) in myoma patients than in controls. Neither erythrocyte GSHPx nor catalase activity was significantly correlated with plasma TBARS.

CONCLUSIONS

The elevated lipid peroxidation and disturbed antioxidant enzyme activities demonstrate the potential of oxidative injury in patients with uterine cervicitis and myoma.

UVA-induced oxidative damage to rat liver nuclei: reduction of iron ions and the relationship between lipid peroxidation and DNA damage

Lipid peroxidation and DNA damage and the relationship between the two events were studied in rat liver nuclei irradiated with low dose UVA. Lipid peroxidation was measured as thiobarbituric acid-reactive substances (TBARS) by spectrophotometric method and as malondialdehyde-TBA adduct by HPLC, and DNA damage was measured as 8-hydroxy-deoxyguanosine (8-OH-dGu) and strand breakage (or loss of double-stranded DNA) by a fluorometric analysis of alkaline DNA unwinding method. The results show that UVA irradiation by itself increased nuclear lipid peroxidation but caused little or no DNA strand breakage or 8-OH-dGu. When 0.5 mM ferric (Fe+3) or ferrous (Fe+2) ions were added to the nuclei during UVA irradiation, lipid peroxidation and DNA damage, measured both as 8-OH-dGu and loss of double-stranded DNA, were strongly enhanced. Lipid peroxidation occurred concurrently with the appearance of 8-OH-dGu. Fe3+ ions were reduced to Fe2+ in this UVA/Fe2+/nuclei system. Lipid peroxidation and DNA damage were neither inhibited by scavengers of hydroxyl radical and singlet oxygen nor inhibited by superoxide dismutase and catalase. Inclusion of EDTA or chain-breaking antioxidants, butylated hydroxytoluene (BHT) and diphenylamine (an alkoxy radical scavenger), inhibited lipid peroxidation but not the level of 8-OH-dGu. BHT also did not inhibit the loss of double-stranded DNA in this system. This study demonstrates the reduction of exogenous Fe+3 by UVA when added to rat liver nuclei, and, as a result, oxidative damage is strongly enhanced. In addition, the results show that DNA damage is not a result of lipid peroxidation in this UVA/Fe2+/nuclei system.

Reaction of cyclohexylamine with hypochlorite and enhancement of oxidation of plasma sulfhydryl groups by hypochlorite in vitro

In this study we investigated the reaction of cyclamate and its major metabolite, cyclohexylamine (CyhNH2), with NaOCl. NaOCl at 100 microM was allowed to react with various concentrations of cyclamate and CyhNH2, and the reactivity was compared with those of reduced glutathione (GSH) and ascorbic acid. The results showed that CyhNH2 was less reactive with NaOCl than GSH but was slightly more reactive than ascorbic acid at concentrations below 50 microM. CyhNH2 at 75 and 100 microM did not further decrease NaOCl. Cyclamate was much less reactive than CyhNH2, with only 43% loss in NaOCl at 100 microM cyclamate. When human blood plasma was incubated with 0.75 microM NaOCl, inclusion of CyhNH2 enhanced oxidation of sulfhydryl groups in a concentration-dependent manner, with complete oxidation of SH groups at 7.5 mM CyhNH2. Cyclamate had no effect. This enhancement by CyhNH2 suggests the formation of reactive products from the reaction of CyhNH2 with NaOCl. Absorption spectra demonstrated that reaction of CyhNH2 with NaOCl at pH 7.4 produced N-monochloramine, as evidenced by the appearance of a new peak at 245 nm and by the disappearance of the 292-nm peak of NaOCl. Cyclamate, which contains a sulfamic acid instead of a primary amine, also reacted with NaOCl at pH 7.4, but the reaction was much less pronounced and the product was probably not monochloramine since the peak was at 270 nm rather than at 245 nm. Because cyclamate is an important sweetener in many countries for people with diabetes mellitus, the possibility exists that CyhNH2 may enhance oxidation of important proteins by HOCl/OCl-.

Plasma levels of antioxidant vitamins, selenium, total sulfhydryl groups and oxidative products in ischemic-stroke patients as compared to matched controls in Taiwan

The possible involvement of oxidative damage and antioxidant protection has been suggested in the pathogenesis of stroke which is the second-leading cause of death in Taiwan. In this study we investigated the relationship between ischemic stroke and plasma status of antioxidants and oxidative products. Plasma levels of vitamin A, alpha-tocopherol, carotenoids, selenium (Se), total SH groups (T-SH), thiobarbituric acid-reactive substances (TBARS) and protein carbonyl, a marker of protein damage, were determined in ischemic-stroke patients (n = 36, blood sampled within 24 hrs after the clinical event) in comparison with 21 matched controls. The cholesterol-adjusted carotenoids and vitamin E were significantly lower (P < 0.05) in the plasma of ischemic-stroke patients than those of the controls. TBARS were higher (P < 0.05) in the patients than in the controls but Se, T-SH and protein carbonyls were not significantly different between the two groups. Separation of the patients into small-artery ischemic stroke (SAIS, n = 17) and large-artery ischemic stroke (LAIS, n = 19) groups revealed that both carotenoids/cholesterol and vitamin E/cholesterol ratios were significantly lower in both LAIS and SAIS groups than the controls (n = 21) while vitamin A/cholesterol was not different among the three groups. TBARS were only significantly higher in the LAIS group. The results demonstrated that, within 24 hrs after the clinical event, the acute-ischemic stroke patients had lowered levels of cholesterol-adjusted carotenoids and alpha-tocopherol but elevated levels of TBARS in the plasma as compared to the matched controls. It remains to be resolved as to whether enhanced lipid peroxidation is a cause or a result of lowered antioxidants in ischemic stroke.

Hemolytic effects of dehydroepiandrosterone in vitro

Dehydroepiandrosterone (DHEA), a major steroid secreted by the adrenal gland which decreases with age after adolescence, is available as a over-the-counter product. This study demonstrates that DHEA induced lysis of human red blood cells (RBCs) in a concentration-dependent manner, with ca. 70% hemolysis at 2 mM DHEA at 37 degrees C for 1 hr. Hemolysis induced by 2 mM DHEA was rapid and involved neither hemoglobin oxidation nor lipid peroxidation. The hemolysis was also not inhibited by addition of EDTA, catalase, superoxide dismutase, glucose or a radical scavenger including mannitol, dimethylsulfoxide and alpha-tocopherol, indicating a non-oxidative mechanism. RBCs stored overnight before incubation with DHEA were hemolyzed to a lesser extent than the freshly prepared RBCs. Light microscopy of the fresh RBCs following 1-h incubation with 2 mM DHEA revealed thickened and cup-shaped deformity of the membranes, suggesting a change in the membrane structure possibly due to the intercalation of the steroid into the membranes.

Ascorbic acid inhibits lipid peroxidation but enhances DNA damage in rat liver nuclei incubated with iron ions

In this report we studied DNA damage and lipid peroxidation in rat liver nuclei incubated with iron ions for up to 2 hrs in order to examine whether nuclear DNA damage was dependent on membrane lipid peroxidation. Lipid peroxidation was measured as thiobarbituric acid-reactive substances (TBARS) and DNA damage was measured as 8-OH-deoxyguanosine (8-OH-dG). We showed that Fe(II) induced nuclear lipid peroxidation dose-dependently but only the highest concentration (1.0 mM) used induced appreciable 8-OH-dG. Fe(III) up to 1 mM induced minimal lipid peroxidation and negligible amounts of 8-OH-dG. Ascorbic acid enhanced Fe(II)-induced lipid peroxidation at a ratio to Fe(II) of 1:1 but strongly inhibited peroxidation at ratios of 2.5:1 and 5:1. By contrast, ascorbate markedly enhanced DNA damage at all ratios tested and in a concentration-dependent manner. The nuclear DNA damage induced by 1 mM FeSO4/5 mM ascorbic acid was largely inhibited by iron chelators and by dimethylsulphoxide and mannitol, indicating the involvement of OH. Hydrogen peroxide and superoxide anions were also involved, as DNA damage was partially inhibited by catalase and, to a lesser extent, by superoxide dismutase. The chain-breaking antioxidants butylated hydroxytoluene and diphenylamine (an alkoxyl radical scavenger) did not inhibit DNA damage. Hence, this study demonstrated that ascorbic acid enhanced Fe(II)-induced DNA base modification which was not dependent on lipid peroxidation in rat liver nuclei.

Nutritional evaluation of women in urban areas in continental China

In 1993-1995, a nutritional survey was conducted in China, in which 50 women each in three cities of Beijing, Shanghai and Nanning (thus 150 in total) volunteered to offer 24-hr total food duplicates and peripheral blood samples. People daily took 1,776 kcal (7,431 kJ) energy, 57 g protein, 75 g lipid, 218 g carbohydrate, 439 mg calcium, 24 mg iron, 3,398 mg sodium and 1,521 mg potassium. When compared with the recommended dietary allowance for Chinese, intakes of energy, iron and possibly vitamin C were sufficient in a majority of the participants, but not so in cases of calcium, and several vitamins. The lipid energy ratio was 38% on an average and was higher than 30% in a majority (73%) of the people. BMI, but not the lipid energy ratio, correlated with the serum triglyceride level. In accordance with high iron intake, the prevalence of anemia was low. Inter-city differences were evident in nutrient sources. Thus, Beijing people took more amounts of protein and lipid from meats (including eggs and milk), whereas plant-based foods were important sources of lipid in Shanghai and that of protein in Nanning. Furthermore, consumption of rice was significantly lower in Beijing than in Shanghai and Nanning, whereas wheat consumption was higher in Beijing than in Shanghai and Nanning.

UVA-potentiated damage to calf thymus DNA by Fenton reaction system and protection by para-aminobenzoic acid

Calf thymus DNA was irradiated with low-intensity UVA (main output at 365 nm, 2 mW cm-2 or 36 kJ m-2 for 30 min), and the role of metal ions, hydrogen peroxide and reactive oxygen species (ROS) was examined. DNA damage was measured as thiobarbituric acid-reactive substances (possibly from degradation of deoxyribose) and as changes in ethidium bromide-DNA fluorescence due to unwinding from strand breaks. Under the present experimental conditions, UVA alone or in the presence of H2O2 had no effect on DNA but slightly enhanced the damage by iron/EDTA. Ultraviolet A strongly enhanced DNA damage (ca four- to five-fold) by the Fenton reaction system (50 microM Fe2+/100 microM EDTA + 0.5 mM H2O2). The results suggest that the Fenton reaction system was "photosensitized" to damage DNA by low-intensity UVA radiation. The enhanced damage by UVA was attributed in part to the reduction of Fe3+ to Fe2+. Ultraviolet A had no effect when iron (ferric or ferrous) ions were replaced by Cu2+, Zn2+, Mn2+ or Cd2+. The ROS involved in the UVA-enhanced damage to DNA by the Fenton reagents were OH and, to a lesser extent, superoxide anions. The UVA-potentiated DNA damage by the Fenton reaction system was then used to examine the protective effect of para-aminobenzoate (PABA), a UVB-absorbing sunscreen that protects against photocarcinogenesis in hairless mice. The results show that PABA and mannitol dose-dependently inhibited the damage with concentrations required for 50% inhibition at 0.1 mM and 3 mM, respectively. The protection by PABA was attributed to its radical-scavenging ability because PABA does not absorb light in the UVA region. These findings may be relevant to the biological damage by UVA and suggest that PABA is useful in protection against photocarcinogenesis by wide-range UV radiation.

The antioxidant and prooxidant activity of some B vitamins and vitamin-like compounds

The antioxidant and prooxidant properties of some B vitamins (BVIT) and vitamin-like compounds (VLC) that are commonly included in multivitamin preparations were investigated. Microsomal lipid peroxidation induced by FeCl3 and ascorbate was dose-dependently inhibited by pyridoxal and pantothenate but was stimulated by thiamin, pyridoxine and carnitine. Among the compounds tested, only pyridoxine and pyridoxal reacted, but rather poorly, with superoxide anions. All test compounds reacted with .OH with second-order rate constants comparable or higher than that for mannitol, as assayed using deoxyribose oxidation by a system containing EDTA-chelated Fe(III), H2O2 and ascorbate. When assayed in the absence of EDTA, pyridoxal showed increased inhibition of deoxyribose oxidation over that in the presence of EDTA, suggesting a potent ability of pyridoxal to bind and deactivate iron. Pantothenate, pyridoxine and myo-inositol appeared to equally inhibit deoxyribose oxidation both in the presence and absence of EDTA. The lack of inhibition on deoxyribose oxidation in the absence of EDTA by thiamin, carnitine and choline may suggest that the .OH-scavenging ability is equalled by the ability of the scavenger-iron complexes to form .OH or other redox active species. However, stimulation of lipid peroxidation by pyridoxine was unexplained and the effect was not attributed to reduction of Fe(III) to Fe(II). This study shows that the radical-scavenging ability of BVIT and VLC did not correlate with their effects on microsomal lipid peroxidation. Moreover, the stimulation of lipid peroxidation by thiamin, pyridoxine and carnitine suggests that supplementation of large amounts of these compounds may not be desirable.

Some similarities in vascular effects of oleic acid and oxidized low-density lipoproteins on rabbit aorta

In the present study oxidized low-density lipoproteins (ox-LDL) was prepared by a new simple method: oxidizing LDL by electrolysis-generated free radicals. In endothelium-intact norepinephrine(NE)-precontracted rabbit aortic rings, ox-LDL (2 mg protein/ml)-incubation for 30 min or 3 mM oleic acid for 10 min, significantly attenuated the acetylcholine (ACh)-induced endothelium-dependent relaxation (EDR) (both P < 0.01 v control). Such attenuated EDR were sustained after washout. The oleic acid-induced endothelial dysfunction was associated with concomitant reduction of cGMP level in aortic rings. Preincubation of aortic rings with 500 microM L-arginine or 100 u/ml superoxide dismutase for 10 min partly prevented the oleic acid-induced attenuation of EDR and reduction of cGMP, indicating that oleic acid may impair the L-arginine-nitric acid pathway and/or inactivate the nitric oxide. Both ox-LDL and oleic acid potentiated NE-induced aortic ring contraction (both P < 0.01 v control). Such potentiating effects were abolished by preincubation with 1 microM verapamil, indicating the possible involvement of calcium influx in vascular smooth muscle cells during the enhanced contraction. Gas-chromatographic analysis showed that oleic acid content is the highest among all free fatty acids in ox-LDL. In conclusion, we found that oleic acid possesses certain similar vascular effects as ox-LDL in inducing endothelial dysfunction and in enhancing NE-induced vasocontraction in rabbit aortic ring. We proposed that the vasoactive effects of ox-LDL may be resulted partly from the activation or release of active oleic acid molecule during oxidative modification of LDL.

Potentiation of oxidative damage to rat red blood cells by the concurrent presence of t-butyl hydroperoxide and bromotrichloromethane

Recently potentiation of oxidative damage in rat red blood cells (rRBC) incubated with t-butylhydroperoxide (BHP) in combination with bromotrichloromethane (BrCCI3) was demonstrated. The mechanism by which this combination (BrCCI3/BHP) potentiates the oxidative damage to rRBC was investigated in this study. When rRBC were incubated with 0.1 mM BHP, 0.5 mM BrCCI3, or the two combined, BrCCI3/BHP-potentiated lipid peroxidation and hemolysis were further enhanced under anaerobic conditions. However, the potentiation of lipid peroxidation was abolished by heating or trypsin digestion of rRBC. Electron spin resonance (ESR) studies demonstrated an increase of alkoyl radical induced by BrCCI3/BHP in rRBC, and this increase was abolished by heating or predigestion of hemolysates with trypsin. The inhibition of lipid peroxidation by diphenylamine (which reacts with alkoxyl radicals but not peroxyl radicals) suggests an important role of alkoxyl radicals. Overall, the present findings demonstrate that the increase in radical-related oxidative damage, possibly mediated by proteinlike materials, may be at least partially responsible for the potentiation of damage to rRBC induced by BrCCI3/BHP, and perhaps by BrCCI3. Although the in vivo significance of these results remains to be investigated, it seems likely that halocarbon toxicity may be amplified by elevated levels of lipid peroxide in blood.

Interactions of human blood plasma with hydrogen peroxide and hypochlorous acid

Activated neutrophils produce both hydrogen peroxide (H2O2) and hypochlorous acid (HOCl). Previous work has shown that HOCl depletes antioxidants, modifies proteins, and forms fatty acid chlorohydrins but does not cause significant lipid peroxidation in human plasma. Because activated phagocytes have been claimed to stimulate lipid peroxidation in plasma, we examined the effects of H2O2 and HOCl alone and in combination on plasma constituents. Hydrogen peroxide at concentrations below 0.5 mmol/L had little effect, but 1 to 2 mmol/L H2O2 caused loss of ascorbic acid and protein thiol groups, an effect potentiated by preincubation of the plasma with sodium azide to inhibit catalase. H2O2 caused no detectable lipid peroxidation or loss of alpha-tocopherol in plasma, but some depletion of ubiquinol occurred. The combination of HOCl and H2O2 caused more lipid peroxidation than either agent alone. Peroxidation was not inhibited by the metal chelators ethylenediaminetetraacetic acid and deferoxamine or by the singlet O2/hydroxyl radical scavenger histidine. We hypothesize that the phagocyte-derived H2O2 and HOCl could interact in the microenvironment of the activated leukocyte to induce lipid peroxidation of plasma lipoproteins or cell membranes (or both).