Influence of Obstructive Sleep Apnea on the Risk of Dental Caries: Insights from a 13-Year Population-Based Retrospective Study

KNOWLEDGE TRANSFER STATEMENT

Obstructive sleep apnea has been proven to have a great negative impact on patients, and the relationship between sleep apnea and dental caries is still inconclusive. Our study shows that patients with sleep apnea and those older than 45 y have a significant risk of dental caries.

Clinical Course and Outcomes of 3,060 Patients with Coronavirus Disease 2019 in Korea, January-May 2020

BACKGROUND

The fatality rate of patients with coronavirus disease 2019 (COVID-19) varies among countries owing to demographics, patient comorbidities, surge capacity of healthcare systems, and the quality of medical care. We assessed the clinical outcomes of patients with COVID-19 during the first wave of the epidemic in Korea.

METHODS

Using a modified World Health Organization clinical record form, we obtained clinical data for 3,060 patients with COVID-19 treated at 55 hospitals in Korea. Disease severity scores were defined as: 1) no limitation of daily activities; 2) limitation of daily activities but no need for supplemental oxygen; 3) supplemental oxygen via nasal cannula; 4) supplemental oxygen via facial mask; 5) non-invasive mechanical ventilation; 6) invasive mechanical ventilation; 7) multi-organ failure or extracorporeal membrane oxygenation therapy; and 8) death. Recovery was defined as a severity score of 1 or 2, or discharge and release from isolation.

RESULTS

The median age of the patients was 43 years of age; 43.6% were male. The median time from illness onset to admission was 5 days. Of the patients with a disease severity score of 3-4 on admission, 65 (71.5%) of the 91 patients recovered, and 7 (7.7%) died due to illness by day 28. Of the patients with disease severity scores of 5-7, 7 (19.5%) of the 36 patients recovered, and 8 (22.2%) died due to illness by day 28. None of the 1,324 patients who were < 50 years of age died; in contrast, the fatality rate due to illness by day 28 was 0.5% (2/375), 0.9% (2/215), 5.8% (6/104), and 14.0% (7/50) for the patients aged 50-59, 60-69, 70-79, and ≥ 80 years of age, respectively.

CONCLUSION

In Korea, almost all patients of < 50 years of age with COVID-19 recovered without supplemental oxygen. In patients of ≥ 50 years of age, the fatality rate increased with age, reaching 14% in patients of ≥ 80 years of age.

Clinical Course and Outcomes of Patients with Severe Acute Respiratory Syndrome Coronavirus 2 Infection: a Preliminary Report of the First 28 Patients from the Korean Cohort Study on COVID-19

BACKGROUND

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-infected pneumonia emerged in Wuhan, China in December 2019. In this retrospective multicenter study, we investigated the clinical course and outcomes of novel coronavirus disease 2019 (COVID-19) from early cases in Republic of Korea.

METHODS

All of the cases confirmed by real time polymerase chain reaction were enrolled from the 1st to the 28th patient nationwide. Clinical data were collected and analyzed for changes in clinical severity including laboratory, radiological, and virologic dynamics during the progression of illness.

RESULTS

The median age was 40 years (range, 20-73 years) and 15 (53.6%) patients were male. The most common symptoms were cough (28.6%) and sore throat (28.6%), followed by fever (25.0%). Diarrhea was not common (10.7%). Two patients had no symptoms. Initial chest X-ray (CXR) showed infiltration in 46.4% of the patients, but computed tomography scan confirmed pneumonia in 88.9% (16/18) of the patients. Six patients (21.4%) required supplemental oxygen therapy, but no one needed mechanical ventilation. Lymphopenia was more common in severe cases. Higher level of C-reactive protein and worsening of chest radiographic score was observed during the 5-7 day period after symptom onset. Viral shedding was high from day 1 of illness, especially from the upper respiratory tract (URT).

CONCLUSION

The prodromal symptoms of COVID-19 were mild and most patients did not have limitations of daily activity. Viral shedding from URT was high from the prodromal phase. Radiological pneumonia was common from the early days of illness, but it was frequently not evident in simple CXR. These findings could be plausible explanations for the easy and rapid spread of SARS-CoV-2 in the community.

Prevalence of Maternal Affective Disorders in Chinese Mothers of Preschool Children with Autism Spectrum Disorders

OBJECTIVES

To evaluate the prevalence of affective disorders and identify their associated factors among Chinese mothers of preschool children diagnosed with autism spectrum disorders.

METHODS

This cross-sectional study was conducted at the Autism Spectrum Disorders Multidisciplinary Clinic of the United Christian Hospital from August 2012 to June 2013. All mothers of a consecutive series of preschool children diagnosed with autism spectrum disorders at their first visit to the clinic were recruited. Information regarding the child-related, maternal, and environmental factors was collected. Psychiatric diagnoses were made according to the Chinese-Bilingual Structured Clinical Interview for DSM-IV Axis I Disorders. Independent factors associated with maternal affective disorders were determined by univariate and multivariate analyses.

RESULTS

Of the 121 subjects, the point prevalence of affective disorders as a group was 29.8%. The point prevalence of major depressive disorders, adjustment disorders, anxiety disorders, and bipolar affective disorders was 14.9%, 10.7%, 3.3% and 0.8%, respectively. A higher level of disruptive and self-absorbed behaviours in the children (as assessed by the Developmental Behaviour Checklist), a higher level of affiliate stigma (as assessed by 22-item Affiliate Stigma Scale), and a history of psychiatric disorders were independently associated with current affective disorders.

CONCLUSION

Psychiatric disorders, predominantly affective disorders, are common among Chinese mothers of preschool children with autism spectrum disorders. Identification of independent factors associated with maternal affective disorders can aid in the early detection of cases and planning of early intervention programmes to address both child and maternal psychological needs.

Relationship between serum testosterone and nocturia in men without benign prostate enlargement

Recent studies have focused on the relationship between nocturia and serum testosterone because testosterone is thought to be an important factor of prostate growth. However, it remains unclear whether altered serum concentrations of testosterone is associated with an increased risk of nocturia because patients who were taking diuretics or who had a large prostate, which may precipitate nocturia, were not excluded from most previous studies. We analyzed the clinical records of 596 non-benign prostatic enlargement (BPE) male patients to explore the relationship between serum total testosterone and nocturia. All patients were evaluated using a serum prostate-specific antigen (PSA) assay, measurement of serum total testosterone, transrectal ultrasonography, uroflowmetry, and a compilation of the International Prostate Symptom Score (IPSS) and International Index of Erectile Function (IIEF) questionnaires. Nocturia was defined as ≥2 nocturnal voiding episodes. The number of nocturia episodes was assessed using IPSS question 7. To evaluate the effect of serum testosterone on nocturia, multivariate regression analysis was performed including the covariates of age, IPSS, IIEF score, body mass index, PSA, prostate volume, and maximal urine flow rate. Based on multivariate linear analysis, serum testosterone level was not significantly associated with the severity of nocturia. However, with regard to the relationship between prevalence of nocturia and serum testosterone, prevalence of nocturia was significantly positively associated with age (OR = 1.048, p = 0.005), total IPSS (OR = 1.217, p < 0.001), and testosterone level (OR = 1.150, p = 0.041). Therefore, in men without an enlarged prostate, testosterone may play an opposing role in the etiology of nocturia.

Belching during gastroscopy and its association with gastroesophageal reflux disease

Belching may result from transient lower esophageal sphincter relaxation; therefore, it has been proposed that belching may be a manifestation of gastroesophageal reflux disease (GERD). This study was conducted to investigate the frequency of belching during esophagogastroduodenoscopy (EGD) and its association with GERD. A retrospective review was performed on prospectively collected clinical and endoscopic data from 404 subjects who underwent EGD without sedation from December 2012 to May 2013 in a training hospital in Korea. All detectable belching events during endoscopy were counted. Frequency and severity of belching events were compared between the group with and without GERD using an ordinal logistic regression model. There were 145 GERD patients (26 erosive reflux disease and 119 nonerosive reflux disease [NERD]). In the multivariable analysis, GERD was significantly associated with a higher frequency of belching events (odds ratio = 6.59, P < 0.001). Central obesity, female, and younger age were also risk factors for frequent belching during EGD. Subgroup analyses were performed in subjects without erosive reflux disease (n = 378) and NERD (n = 293). NERD was also a predictive factor for frequent belching during EGD (odds ratio = 6.61, P < 0.001), and the frequency of belching was significantly correlated with GERD severity according to the Los Angeles classification (P < 0.05). Frequent belching during EGD was associated with GERD, including NERD. Future research should focus on its adjuvant role in the diagnosis of GERD/NERD and the necessity for applying differentiated endoscopy strategies for GERD patients, leading to less discomfort during EGD in patients at risk for intolerability.

Evaluation of Bond Strength and Microleakage of a Novel Metal-titanate Antibacterial Agent

OBJECTIVES

To evaluate the effect on both bond strength and microleakage of incorporation of a novel antibacterial nanoparticulate metal-titanate complex (nMT) into a dental adhesive system.

MATERIALS AND METHODS

Eighty extracted human molars were prepared to determine whether incorporation of nMT into bonding agents can affect shear bond strength (SBS) and adhesive strength fatigue. SBS was measured with a universal testing machine, and the peak force at failure was recorded. An electromechanical fatigue machine was used for cyclic loading treatment of specimens. Differences in the SBS values among groups were identified using analysis of variance and Tukey post hoc analyses (α=0.05). Twenty standard Class V cavities were restored to examine microleakage when the primer/bonding resin was modified with 10 wt% nMT. Microleakage at the enamel and dentin margins was calculated as a percentage of the full length of the cavity. Results of the microleakage experiment were analyzed with paired and independent sample t-tests (α=0.05).

RESULTS

The mean (± standard deviation) shear bond strength values of before fatigue and after fatigue ranged from 21.9 (2.5) MPa to 23.9 (3.8) MPa and from 17.1 (2.5) MPa to 17.7 (2.5) MPa respectively. No statistically significant differences in failure force were observed among groups (p=0.70). Microleakage under all conditions was significantly greater in the dentin margins than in the enamel margins (p<0.05). There was no evidence that microleakage differed between the experimental groups with modified primer and bonding resin.

CONCLUSIONS

Incorporating nMT into a dental adhesive system will not compromise the resin composite's tooth bonding and sealing ability.

Predicting potential drop-out and future commitment for first-time donors based on first 1·5-year donation patterns: the case in Hong Kong Chinese donors

BACKGROUND AND OBJECTIVES

Adequate blood supply is crucial to the health-care system. To maintain a stable donor pool, donation-promotion strategies should not only be targeted in recruitment but also focus on retaining donors to give blood regularly. A study using statistical modelling is conducted to understand the first 4-year donation patterns for drop-out and committed first-time blood donors and to build model for the donor-type identification based on their first 1.5-year donation patterns.

SUBJECTS AND METHODS

First-time whole blood (n= 20 631) adult donors recruited in year 2000 and 2001 in Hong Kong were observed for more than 4 years. Cluster analysis was first applied to group donor type by their similarities in donation behaviour under the surveillance period. A decision tree model based on a shorter surveillance period (1.5 years) is then built to predict the donor type.

RESULTS

Three donation patterns - one-time, drop-out, and committed donor behaviour - were identified in cluster analysis. Three variables - donation frequencies in the first-year and in the half-year period after first year, and the number of donation centre visits in the following half year after first year, were able to predict drop-out donors with potential to become committed and committed donors with relatively lower donation frequency.

CONCLUSIONS

The present statistical modelling is able to identify those donors with potential to become committed donors and those committed donors who can donate more frequently. This information is useful for development of targeted donor retention strategies.

Inhibition of angiogenesis and tumor progression by hydrodynamic cotransfection of angiostatin K1-3, endostatin, and saxatilin genes

In vivo expression of angiostatin and endostatin, two different types of endothelial cell growth inhibitor, have been reported to inhibit vascularization in tumor tissues, resulting in tumor growth inhibition. Recently, in vivo expression of saxatilin, a novel disintegrin purified from snake (Gloydius saxatilis) venom, was able to strongly inhibit endothelial cell proliferation and smooth muscle cell migration, resulting in tumor growth inhibition. However, the antitumor efficacy of the individual antiangiogenic molecules expressed in vivo was not sufficiently potent to induce tumor regression in animal models. Therefore, in this study, we have systemically examined how combinational transfer of angiostatin, endostatin, and saxatilin genes affects neovascularization in tumor tissues and tumor progression in a mouse model. In Matrigel-implanted mice, cotransfection with plasmids encoding angiostatin K1-3 (pFLAG-Angio K1/3), endostatin (pFLAG-Endo), and saxatilin (pFLAG-Sax) resulted in the most effective inhibition of angiogenesis. In addition, hydrodynamic cotransfection of the three genes induced more inhibition of B16BL6 melanoma growth and pulmonary metastasis than other combinations of transfected genes. Compared with the empty vector-treated control group, cotreatment with the three plasmids reduced B16BL6 tumor growth by 89% and pulmonary metastasis by 90%. These results provide additional evidence supporting the combined systemic expression of antiangiogenic factors, such as angiostatin K1-3, endostatin, and saxatilin, as an alternative procedure for antiangiogenic cancer therapy.

Comparison of synchronous and laser-induced fluorescence spectroscopy applied to the Eu(III)-fulvate complexation

The complexation of europium ion (Eu(III)) with a soil fulvic acid (FA) has been studied at pH 5 in 0.01M NaClO(4) by different experimental methods, i.e. synchronous fluorescence spectroscopy (SyFS) and time resolved laser-induced fluorescence spectroscopy (TRLFS). A series of SyFS quenching spectra was obtained by increasing the Eu(III) concentration and keeping the FA concentration constant. The emission spectra and fluorescence lifetimes of the Eu(III) bound to the FA were also measured by a TRLFS system using the same solution used in the SyFS spectral measurement. From the analysis of the fluorescence data obtained by the SyFS and the TRLFS using a non-linear least-squares method, the concentration of the binding sites (C(L)) of the FA accessible for the Eu(III) and the corresponding conditional stability constants (logK) were estimated. The two different methods gave rise to constants being comparable with one another. The logK and C(L) values (mean +/- standard deviation of three determinations) determined by the SyFS were 6.4 +/- 0.2 (6.7 +/- 0.1mumolL(-1): by the TRLFS) and 10 +/- 1mumolL(-1) (7 +/- 1mumolL(-1): by the TRLFS), respectively. The applicability of the FA fluorescence quenching techniques for estimating the europium binding parameters was proved by the direct monitoring of the Eu(III) bound to the FA using the TRLFS system.

Global pollution monitoring of PCBs and organochlorine pesticides using skipjack tuna as a bioindicator

Concentrations of organochlorines (OCs) representing persistent organic pollutants (POPs), such as polychlorinated biphenyls (PCBs), dichlorodiphenyl trichloroethane and its metabolites (DDTs), chlordane compounds (CHLs), hexachlorocyclohexane isomers (HCHs), and hexachlorobenzene (HCB), were determined in the liver of skipjack tuna (Katsuwonus pelamis) collected from the offshore waters of various regions in the world (offshore waters around Japan, Taiwan, Philippines, Indonesia, Seychelles, and Brazil, and the Japan Sea, the East China Sea, the South China Sea, the Bay of Bengal, and the North Pacific Ocean). OCs were detected in livers of all of the skipjack tuna collected from the locations surveyed, supporting the thesis that there is widespread contamination of persistent OCs in the marine environment. Within a location, no significant relationship between growth-stage (body length and weight) and OC concentrations (lipid weight basis) was observed, and the OC residue levels were rather uniform among the individuals. Interestingly, the distribution of OC concentrations in skipjack tuna was similar to those in surface seawaters from which they were taken. These results suggest that OC concentrations in skipjack tuna could reflect the pollution levels in seawater from which they are collected and that this species is a suitable bioindicator for monitoring the global distribution of OCs in offshore waters and the open ocean. Concentrations of PCBs and CHLs in skipjack tuna were higher in offshore waters around Japan (up to 1100 and 250 ng/g lipid wt, respectively), suggesting the presence of sources of PCBs and CHLs in Japan. High concentrations of DDTs and HCHs were observed in samples from the Japan Sea, the East China Sea, the South China Sea, and the Bay of Bengal (up to 1300 and 22 ng/g lipid wt, respectively). This result suggests recent use of technical DDT and HCH for agricultural and/or public health purposes in Russia, China, India, and some other developing Asian countries. Relatively high concentrations of PCBs, CHLs, HCHs, and HCB were also observed in samples collected from some locations in the middle of the Pacific Ocean, indicating the expansion of OC contamination on a global scale. Considering these facts, continuous studies monitoring these compounds in offshore waters and the open seas, using skipjack tuna as a bioindicator, are needed to further understand the future trend of contamination.

A randomized controlled trial of tolterodine and oxybutynin on tolerability and clinical efficacy for treating Chinese women with an overactive bladder

Objective To compare the tolerability and clinical efficacy of tolterodine and oxybutynin in the treatment of Hong Kong Chinese women with an overactive bladder. Patients and methods A randomized controlled trial was conducted at two urogynaecology centres in Hong Kong. In all, 106 women with urodynamically confirmed detrusor instability were recruited. Baseline severity assessments included a visual analogue scale (VAS), urinary diary and urinary pad-test. The women were randomized to receive either oral tolterodine 2 mg or oxybutynin 5 mg twice daily for 10 weeks. Treatment responses were assessed at 4 and 10 weeks using the VAS and urinary diary. Treatment tolerability was assessed at baseline, 4 and 10 weeks using the Xerostomia Questionnaire. A urinary pad-test was repeated at 10 weeks. Results The perceived change from baseline VAS was better in the tolterodine than the oxybutynin group after 10 weeks of treatment (per-protocol analysis, P = 0.043). The two drugs were effective in reducing the symptoms of frequency (P < 0.001). Tolterodine was significantly better than oxybutynin in reducing urinary leakage (urinary pad-test; median change - 5.00 g vs 0 g, P = 0.019). Both drugs caused a significant worsening of dry mouth (overall dryness, P < 0.005; discomfort, P < 0.005; sleep, P = 0.021; speaking, P = 0.045; swallowing, P = 0.004; and liquid consumption, P = 0.017). Conclusions Both oxybutynin and tolterodine were effective in ameliorating the severity of the symptoms of detrusor instability. Tolterodine was better than oxybutynin in both subjective and objective outcome measures, but both drugs caused similar worsening of dry mouth that may limit the tolerability of these medications.

Measurement of 90sr in aqueous samples using liquid scintillation counting with full spectrum DPM method

90Sr activity was measured with the full spectrum DPM (FS-DPM) counting method after plotting the quench correction curves of 90Sr and 90Y, and the FS-DPM method was applied to determine the 90Sr in liquid waste samples. The optimum regions of 90Sr and 90Y were set for measuring 90Sr with the dual label DPM (DL-DPM) method. The direct measurement of purified 90Sr with spectrum unfolding techniques could overcome the disadvantages of the DL-DPM method. The activities of 90Sr in the 90Sr/90Y standardized solution measured with the FS-DPM protocols were close to the true activity. The concentrations of 90Sr in the liquid waste samples measured with the FS-DPM counting method were compared with those obtained with conventional methods.

Prevalence of Helicobacter pylori infection in gastric remnant after distal gastrectomy for primary gastric cancer

BACKGROUND

The development of a second primary cancer in the gastric remnant after gastrectomy for early gastric carcinoma is a problem, and eradication of Helicobacter pylori after the operation has been recommended. However, to date, practical indications for H. pylori eradication after gastric cancer surgery have not yet been reported.

METHODS

We examined H. pylori infection in the gastric remnant after distal gastrectomy for primary gastric cancer. One hundred and nine patients who had had a gastrectomy were studied. Endoscopic findings and results from the urease test, bacteriologic assessment, serological test, and histopathological examination were analyzed.

RESULTS

Seventy-one patients (65.1%) were judged to be positive for H. pylori infection. The prevalence of H. pylori infection was found to be significantly decreased in older patients, patients in whom the operation had been performed a long time before examination, patients with symptoms, and patients with severe reflux gastritis. On the other hand, histologically, chronic and acute gastritis correlated significantly with H. pylori infection. H. pylori prevalence was highest in mildly atrophic mucosa and decreased with more extensive atrophic changes of the mucosa.

CONCLUSIONS

The persistence of H. pylori-related active gastritis in the gastric remnant after gastric cancer surgery was suggested in younger patients with mild atrophic gastritis and without reflux gastritis. These patients may be the best candidates for H. pylori eradication therapy.

Prevalence of Helicobacter pylori infection in gastric remnant after distal gastrectomy for primary gastric cancer

BACKGROUND

The development of a second primary cancer in the gastric remnant after gastrectomy for early gastric carcinoma is a problem, and eradication of Helicobacter pylori after the operation has been recommended. However, to date, practical indications for H. pylori eradication after gastric cancer surgery have not yet been reported.

METHODS

We examined H. pylori infection in the gastric remnant after distal gastrectomy for primary gastric cancer. One hundred and nine patients who had had a gastrectomy were studied. Endoscopic findings and results from the urease test, bacteriologic assessment, serological test, and histopathological examination were analyzed.

RESULTS

Seventy-one patients (65.1%) were judged to be positive for H. pylori infection. The prevalence of H. pylori infection was found to be significantly decreased in older patients, patients in whom the operation had been performed a long time before examination, patients with symptoms, and patients with severe reflux gastritis. On the other hand, histologically, chronic and acute gastritis correlated significantly with H. pylori infection. H. pylori prevalence was highest in mildly atrophic mucosa and decreased with more extensive atrophic changes of the mucosa.

CONCLUSIONS

The persistence of H. pylori-related active gastritis in the gastric remnant after gastric cancer surgery was suggested in younger patients with mild atrophic gastritis and without reflux gastritis. These patients may be the best candidates for H. pylori eradication therapy.

Synthesis and binding affinities of 2 beta-(3-iodoallyloxycarbonyl)-3 beta-(4-substituted-aryl)tropane analogues as ligands for the dopamine transporter studies

Tropane analogues from cocaine, which is known to be one of the most reinforcing and addictive compounds, were designed, synthesized, and characterized for inhibition of presynaptic uptake of dopamine (DA) in brain. Eight new derivatives of 3 beta-aryl-2 beta-(3-iodoallyloxycarbonyl)tropanes were synthesized and tested for their potential abilities to displace [(3)H]2 beta-carbomethoxy-3 beta-(4-fluorophenyl)tropane (WIN 35,428) binding to the rat striatal membranes.

Antiplatelet activity of green tea catechins is mediated by inhibition of cytoplasmic calcium increase

We have previously reported that green tea catechins (GTC) display a potent antithrombotic activity, which might be due to antiplatelet rather than anticoagulation effects. In the current study, we investigated the antiplatelet mechanism of GTC. We tested the effects of GTC on the aggregation of human platelets and on the binding of fluorescein isothiocyanate-conjugated fibrinogen to human platelet glycoprotein (GP) IIb/IIIa. GTC inhibited the collagen-, thrombin-, adenosine diphosphate (ADP)-, and calcium ionophore A23187-induced aggregation of washed human platelets, with 50% inhibitory concentration values of 0.64, 0.52, 0.63, and 0.45 mg/ml, respectively. GTC significantly inhibited fibrinogen binding to human platelet surface GPIIb/IIIa complex but failed to inhibit binding to purified GPIIb/IIIa complex. These results indicate that the antiplatelet activity of GTC may be due to inhibition of an intracellular pathway preceding GPIIb/IIIa complex exposure. We also investigated the effects of GTC on intracellular calcium levels, which are critical in determining the activation status of platelets and on induction of platelet aggregation by thapsigargin, which is a selective inhibitor of the Ca(2+)-ATPase pump. Pretreatment of human platelets with GTC significantly inhibited the rise in intracellular Ca(2+) concentration induced by thrombin treatment, and GTC significantly inhibited the thapsigargin-induced platelet aggregation. We also examined the effect of GTC on the second messenger, inositol 1,4,5-triphosphate (IP(3)). GTC significantly inhibited the phosphoinositide breakdown induced by thrombin. Taken together, these observations suggest that the antiplatelet activity of GTC is be mediated by inhibition of cytoplasmic calcium increase, which leads to the inhibition of fibrinogen-GPIIb/IIIa binding via the activation of Ca(2+)-ATPase and inhibition of IP(3) formation.

Establishment of a new scirrhous gastric cancer cell line with loss of heterozygosity at E-cadherin locus

Scirrhous gastric carcinoma, characterized by carcinoma cell proliferation and infiltration with extensive fibrosis in the stroma, frequently causes peritoneal metastasis. We describe here a newly established cell line, OCUM-6, derived from ascites effusion of a scirrhous gastric cancer patient. The cells are floating and round shape, similar to other scirrhous gastric carcinoma cell lines previously reported. Histologic findings of xenografted tumor obtained from OCUM-6 cells showed medullary growth with a poorly differentiated adenocarcinoma containing signet ring cells. LOH at E-cadherin locus 16q22 was observed in the OCUM-6 cells. LOH at E-cadherin locus might be closely associated with histologic findings and metastatic process of scirrhous gastric cancer. The scirrhous gastric cancer cell line, OCUM-6, may be useful for investigation of the mechanisms of peritoneal dissemination and carcinogenesis.

Lung fibrosis in Sprague-Dawley rats, induced by exposure to manual metal arc-stainless steel welding fumes

To investigate the disease process of pneumoconiosis induced by welding-fume exposure, a lung fibrosis model was established by building a stainless steel arc welding fume generation system and exposing male Sprague-Dawley rats for 90 days. The rats were exposed to welding fumes with concentrations of 57-67 mg/m3 (low dose) and 105-118 mg/m3 (high dose) total suspended particulates for 2 h per day in an inhalation chamber for 90 days. The concentrations of the main metals, Fe, Mn, Cr, and Ni, were measured in the welding fumes, plus the gaseous compounds, including nitrous gases and ozone, were monitored. During the exposure period, the animals were sacrificed after the initial 2-h exposure and after 15, 30, 60, and 90 days. Histopathological examinations were conducted on the animals' upper respiratory tract, including the nasal pathway and conducting airway, plus the gas exchange region, including the alveolar ducts, alveolar sacs, and alveoli. When compared to the control group, the lung weights did not increase significantly in the low-dose group, yet in the high-dose group there was a significant increase from day 15 to day 90. The histopathological examination combined with fibrosis-specific staining (Masson's trichrome) indicated that the lungs in the low-dose group did not exhibit any progressive fibrotic changes. Whereas, the lungs in the high-dose group exhibited early delicate fibrosis from day 15, which progressed into the perivascular and peribronchiolar regions by day 30. Interstitial fibrosis appeared at day 60 and became prominent by day 90, along with the additional appearance of pleural fibrosis. Accordingly, it would appear that a significant dose of welding-fume exposure was required to induce lung fibrosis.

A novel recombinant basic fibroblast growth factor and its secretion

Basic fibroblast growth factor (FGF-2) is a pleiotropic mitogen which plays an important role in cell growth, differentiation, migration, and survival in different cells and organ systems. Recently, several clinical applications for FGF-2 gene transfer are being evaluated in wound healing and collateral artery development to relieve myocardial and peripheral ischemia due to the ability of FGF-2 to regulate the growth and function of vascular cells. However, FGF-2 lacks a classical hydrophobic secretion signal peptide, the FGF-2 chimeras containing various signal sequences have been explored. In this study, a novel recombinant 4sFGF-2 was constructed by replacing nine residues from the amino-terminus of native FGF-2 (Met1 to Leu9) with eight amino acid residues of signal peptide of FGF-4 (Met1 to Ala8) to better increase the secretion level of FGF-2. When the recombinant FGF-2 gene, cloned into the expression vector with CMV promoter, was expressed in COS-7 cells, the recombinant 4sFGF-2 was highly secreted into the media. The secreted 4sFGF-2 showed the same biological activity as the native FGF-2 in the dose-response effects on DNA synthesis and cell growth of rat aortic smooth muscle cells (RASMCs) and NIH3T3 cells. The 4sFGF-2 also was able to activate MAPK as wild FGF-2 in RASMCs. These results indicate that a novel recombinant 4sFGF-2 may be useful as clinical applicability of angiogenic growth factor gene transfer.

Antiplatelet effect of 2-chloro-3-(4-acetophenyl)-amino-1,4-naphthoquinone (NQ301): a possible mechanism through inhibition of intracellular Ca2+ mobilization

The effects of 2-chloro-3-(4-acetophenyl)-amino-1,4-naphthoquinone (NQ301), an antithrombotic agent, on aggregation, binding of fibrinogen to glycoprotein (GP)IIb/IIIa complex and intracellular signals were investigated using human platelets. NQ301 significantly inhibited the collagen-, thrombin-, arachidonic acid-, thapsigargin- and calcium ionophore A23187-induced aggregation of washed human platelets with IC50 values of 13.0+/-0.1, 11.2+/-0.5, 21.0+/-0.9, 3.8+/-0.1 and 46.2+/-0.8 microM, respectively. NQ301 also significantly inhibited FITC-conjugated fibrinogen binding to human platelet surface GPIIb/IIIa complex, but failed to inhibit the fibrinogen binding to purified GPIIb/IIIa complex. These data demonstrate that NQ301 inhibits platelet aggregation by suppression of the intracellular pathway, rather than by direct inhibition of fibrinogen-GPIIb/IIIa complex binding. NQ301 significantly inhibited the increase of cytosolic Ca2+ concentration and ATP secretion, and also significantly increased platelet cAMP levels in the activated platelets. These results suggest that the antiplatelet activity of NQ301 may be mediated by inhibition of cytosolic Ca2+ mobilization, enhancement of cAMP production and inhibition of ATP secretion in activated platelets.

Diagnostic usefulness of FDG PET for pancreatic mass lesions

The purpose of this study was to investigate the feasibility of [18F]2-deoxy-2-fluoro-D-glucose (FDG) positron emission tomography (PET) in patients with a pancreatic mass by comparing the results with those of X-ray computed tomography (CT) and magnetic resonance (MR) imaging.

METHODS

Eighty-six patients with pancreatic lesions, included 65 malignant tumors and 21 benign masses (55 masses were proven histologically and the others were diagnosed clinically), were studied. The diagnostic factors of CT and MR imaging were evaluated, and those of FDG PET were also evaluated for malignant and benign masses by visual interpretation and quantitative interpretation with the standardized uptake value (SUV) and SUVgluc which was designed to reduce the effects of a high blood sugar level. Visual interpretations were evaluated only in FDG PET images, and quantitative interpretations were evaluated by referring to CT and/or MR imaging. The correlation between SUV and the degree of histological differentiation in pancreatic ductal adenocarcinoma was investigated.

RESULTS

Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy for CT imaging were 91, 62, 88, 68 and 84%, and for MR imaging 78, 70, 88, 54 and 76%, respectively. In visual interpretation of FDG PET images, the sensitivity, specificity, PPV, NPV and accuracy were 82, 81, 93, 59 and 81%, respectively. Significant differences between malignant and benign lesions existed in SUV and SUVgluc (p < 0.0001, each). With the cutoff value of SUV as 2.1 and SUVgluc as 2.2, the accuracy of diagnosis was maximal. With that cutoff value, the sensitivity, specificity, PPV, NPV and accuracy for SUV were 89, 76, 92, 70 and 86%, and for SUVgluc 91, 76, 92, 73 and 87%, respectively. The sensitivity and NPV of SUVgluc were higher than those of SUV, which suggests that SUVgluc may be more useful in reducing the number of overlooked malignant tumors. The specificity and PPV of FDG PET were superior to those of CT and MR imaging. There were no significant differences between the SUVs of moderately differentiated adenocarcinomas and those of well differentiated adenocarcinomas.

CONCLUSION

To improve the diagnostic procedure for classifying masses, FDG PET with not only SUV but also SUV corrected by the blood sugar level is required in addition to morphological diagnosis by CT and/or MR imaging.

Biochemical characterization of a thrombin-like enzyme and a fibrinolytic serine protease from snake (Agkistrodon saxatilis) venom

A thrombin-like enzyme and a fibrinolytic serine protease were purified to homogeneity from the venom of a Korean snake Agkistrodon saxatilis emelianov. Both the purified enzymes migrated as a single protein band corresponding to 39 kDa in SDS-PAGE. However, the molecular mass was reduced to 28 kDa by enzymatic removal of the N-linked carbohydrates in those two different enzyme species. Although the thrombin-like enzyme and the fibrinolytic protease show homologous features in their molecular sizes and N-terminal amino acid sequences, yet they can be clearly distinguished from each other in terms of substrate specificity, susceptibility to inhibitors and fibrinogen degradation. It is postulated that these two enzymes are capable of functioning in a cooperative manner to effectively remove fibrinogen and consequently to reduce the blood viscosity.

Antiplatelet mechanism of 2-chloro-3-(4-hexylphenyl)-amino-1,4-naphthoquinone (NQ304), an antithrombotic agent

The effects of 2-chloro-3-(4-hexylphenyl)-amino-1,4-naphthoquinone (NQ304), an antithrombotic agent, on aggregation, binding of fibrinogen to glycoprotein IIb/IIIa and intracellular signals were investigated using human platelets. NQ304 inhibited thrombin-, arachidonic acid- and thapsigargin-induced aggregation of washed human platelets with the IC50 values of 22.2+/-0.7, 6.5+/-0.2, and 7.6+/-0.1 microM, respectively. NQ304 significantly inhibited fluorescein isothiocyanate-conjugated fibrinogen binding to human platelet surface glycoprotein IIb/IIIa receptor by 75%, but failed to inhibit the fibrinogen binding to purified glycoprotein IIb/IIIa receptor. This result suggests that NQ304 inhibit platelet aggregation by suppression of an intracellular pathway that involves exposure of the glycoprotein IIb/IIIa receptor, rather than by direct inhibition of fibrinogen-glycoprotein IIb/IIIa binding. NQ304 significantly inhibited thrombin-induced increase in intracellular Ca2+ mobilization at the dose of 30 microM and ATP secretion in a dose-dependent manner. It also inhibited thrombin- and arachidonic acid-induced thromboxane A2 formation in human platelet dose-dependently. In conclusion, the antiplatelet mechanism of NQ304 may be due to the reduction of the thromboxane A2 formation, inhibition of adenosine triphosphate release and intracellular calcium mobilization.

Effect of a capsular tension ring on the shape of the capsular bag and opening and the intraocular lens

PURPOSE

To evaluate the effect of a capsular tension ring (CTR) on the shape of the capsular bag, the extent of the capsular opening, and the shape of intraocular lenses (IOLs).

SETTING

Department of Ophthalmology, College of Medicine, The Catholic University of Korea, Seoul, Korea.

METHODS

The corneal button was removed from porcine eyes in vitro. After phacoemulsification was performed, an IOL alone or an IOL and CTR were inserted in the capsular bag in 6 groups of 5 eyes each. The eyes were examined from the posterior aspect using a Miyake technique to assess capsular bag shape and the capsular opening. To evaluate effects of the CTR on IOL shape, rabbit eyes had phacoemulsification and IOL implantation with and without placement of a CTR in vivo. The IOLs were removed from enucleated eyes 3 months postoperatively and compared with unused control IOLs.

RESULTS

The differences between the maximum and minimum diameters of the capsular bags and capsular openings were significantly less in groups with a CTR. Intraocular lens size (difference from haptic to haptic) decreased significantly in eyes with only an IOL compared with normal controls or eyes with both an IOL and CTR.

CONCLUSIONS

The CTR preserved the integrity of the capsular bag diameter, capsular opening, and IOL shape. It is likely that CTR implantation can avert contracture of the capsular bag and capsular opening, preventing IOL decentration.

A study on carbothermal reduction of sulfur dioxide to elemental sulfur using oilsands fluid coke

Experiments and reaction equilibrium calculations were carried out for the SO2 gas and oilsands fluid coke system. The goal was to develop a coke-based sulfur-producing flue gas desulfurization (SP-FGD) process that removes SO2 from flue gases and converts it into elemental sulfur. The conversion of SO2 to elemental sulfur proceeded efficiently at temperatures higher than 600 degrees C, and the sulfur yield reached a maximum (> 95%) at about 700 degrees C. An increase of temperature beyond 700 degrees C enhanced the reduction of product elemental sulfur, resulting in the formation of reduced sulfur species (COS and CS2), which lowered the sulfur yield at 900 degrees C to 90%. Although equilibrium calculations suggest that a lower temperature favors the conversion of SO2 as well as the yield of elemental sulfur, experiments showed no formation of elemental sulfur at 600 degrees C and below, likely due to hindered kinetics. Faster reduction of SO2 was observed at a higher temperature in the range of 700-1000 degrees C. A complete conversion of SO2 was achieved in about 8 s at 700 degrees C. Prolonging the product gas--coke contact, the yield of elemental sulfur decreased due to the formation of COS and CS2 while the SO2 conversion remained complete. Equilibrium calculations suggest that the ultimate yield of elemental sulfur maximizes at the C/SO2 ratio of 1, which represents the stoichiometry of SO2 + C-->CO2 + S. For the C/SO2 ratio < 1, equilibrium calculations predict elemental sulfur and CO2 being major products, suggesting that SO2 + C-->CO2 + S is the predominant reaction if SO2 is in excess. Experiments revealed that elemental sulfur and CO2 were only major products if the conversion of SO2 was incomplete, which is in agreement with the result of the equilibrium modeling.

A candidate tumor suppressor locus for scirrhous gastric cancer at chromosome 18q 12.2

We investigated LOH on 5q, 16q, 17p, 17q, and 18q in scirrhous gastric cancer and identified the chromosomal locus that is frequently deleted in scirrhous gastric cancer. LOH frequency on 18q of scirrhous gastric cancer was found to be significantly higher than that of the other types of advanced gastric cancer, while no significant difference between LOH at 5q, 16q, 17p and 17q was found. Eight microsatellite markers on chromosome 18q were additionally examined in scirrhous gastric cancer. The highest rates of LOH were observed at the D18S34 locus which is located at 18q12.2. These findings suggest that the D18S34 locus might be a novel candidate tumor suppressor locus in scirrhous gastric carcinoma.

Quantitative assessment of estrogenic activity in the water environment of Korea by the E-SCREEN assay

In this study, the E-SCREEN assay was optimized and validated for the sensitive quantitative determination of the total estrogenicity in river samples. River water and sediment samples were collected and analyzed with the E-SCREEN. River water (10 l) was extracted using combined solid-phase extraction in static adsorption mode with Soxhlet extraction. Estrogenic pollutants adsorbed to the XAD-4 resin were recovered with 98.24 +/- 5.90% efficiency by elution with ethyl acetate and dichloromethane (1:9). The detection limit by 17beta-estradiol equivalent concentration (EEQ) of the E-SCREEN assay was 8.03 pg EEQ/l. Among the water samples, the estrogenic activity was observed to be higher downstream of the Kumho river (7.43 ng EEQ/l) and upstream of Kum river (2.05 ng EEQ/l) than in other samples. More than 3 mg of equivalent sediment samples from the Kumho river, Kum river and Miho stream showed partial agonistic effects, and the Mankyung river showed a partial agonistic effect with only 1.5 mg of sediment. The highest value of RPE was 83.34 downstream of the Kumho river, and the lowest value of RPE was 6.52 downstream of the Miho stream. Full estrogen agonistic activities were observed downstream of the Kumho river and upstream of the Kum river. The partial agonistic activity was observed in upstream of the Kumho river, downstream of the Mankyung river, and upstream of the Miho stream, and no agonistic action was observed downstream of the Kum river or Miho stream, or upstream of the Mankyung river. The total estrogenic activity in the river water and sediment samples was between 0.50 pg/L and 7.4 ng/L, 3.39 pg/g and 10.70 pg/g.

Expression of enhanced green fluorescent protein (EGFP) and neomycin resistant (Neo(R)) genes in porcine embryos following nuclear transfer with porcine fetal fibroblasts transfected by retrovirus vector

In this study, we demonstrated expression of enhanced green fluorescent protein (EGFP) and neomycin resistant (Neo(R)) genes in porcine embryos following nuclear transfer from porcine fetal fibroblasts (PFFs) transduced with the EGFP and Neo(R) genes by retrovirus-mediated infection. Nuclear transfer of the nonstarved transfected PFF into enucleated oocytes was accomplished by cell to cell fusion. Out of 188 porcine eggs reconstructed by nuclear transfer, 116 (61.7%) eggs cleaved and 25 (13.3%) developed to morula and blastocyst stages. Of these 25 morulae and blastocysts, 25 (100%) embryos emitted green fluorescence. Expression of the both EGFP and Neo(R) genes was detected as early as the 2-cell stage. As determined by EGFP gene expression, mosaicism was not observed in any embryo. These results suggest that porcine oocytes reconstructed by nuclear transfer with transfected PFFs can successfully develop to the blastocyst stage. In addition, this approach might be applicable to the production of transgenic pigs with complex genetic modifications.

Inhibition of invasion and lymph node metastasis of gastrointestinal cancer cells by R-94138, a matrix metalloproteinase inhibitor

BACKGROUND

MMPs have been implicated in the process of metastasis. Matlystatin analogue, called R-94138, isolated from Actinomadura atramentaria, has been reported to inhibit the activity of MMP-2 and -9 specifically. In this study, we investigated the effect of R-94138 on the invasive and lymphnodal metastatic ability of gastric cancer cells.

MATERIALS AND METHODS

Three gastric cancer cell lines, MKN-28, MKN-45, MKN-74, and two colorectal cancer cell lines, HT-29, and LS174T were used. The invasion ability of these cell lines were assayed with R-94138 at the required concentration in vitro. The In vivo effect of R-94138 on lymphnode metastasis was examined passaged by orthotopic implantation.

RESULTS

All cell lines revealed activity of both 72 and 92 kDa forms of MMPs by gelatin zymography. R-94138 significantly inhibited the invasiveness of all of these cells to the extracellular matrix. The number of lymph node metastases and the amount of body weight loss were significantly decreased by intraperitoneal administration of R-94138.

CONCLUSION

MMP inhibitor, R-94138, has a possible application in adjunctive therapy for lymph node metastasis in gastric carcinoma.

The cytotoxicity of corrosion products of nitinol stent wire on cultured smooth muscle cells

Although nitinol is one of most popular materials of intravascular stents, there are still few confirmative biocompatibility data available, especially in vascular smooth muscle cells. In this report, the nitinol wires were corroded in Dulbecco's modified Eagle's medium with constant electrochemical breakdown voltage and the supernatant and precipitates of corrosion products were prepared as culture media. The dose and time effects of different concentrations of corrosion products on the growth and morphology of smooth muscle cells were evaluated with [(3)H]-thymidine uptake ratio and cell cycle sorter. Both the supernatant and precipitate of the corrosive products of nitinol wire were toxic to the primary cultured rat aortic smooth muscle cells. The growth inhibition was correlated well with the increased concentrations of the corrosion products. Although small stimulation was found with released nickel concentration of 0.95 +/- 0.23 ppm, the growth inhibition became significant when the nickel concentration was above 9 ppm. The corrosion products also altered cell morphology, induced cell necrosis, and decreased cell numbers. The cell replication was inhibited at the G0-G1 to S transition phase. This was the first study to demonstrate the cytotoxicity of corrosion products of current nitinol stent wire on smooth muscle cells, which might affect the postimplantation neointimal hyperplasia and the patency rate of cardiovascular stents.

Increased corrosion resistance of stent materials by converting current surface film of polycrystalline oxide into amorphous oxide

Current efforts of new stent technology have been aimed largely at the improvement of intravascular stent biocompatibility. Among the chemical characteristics of metallic stents, surface oxide corrosion properties are paramount. Using our unique technique, the currently marketed 316 L stainless steel and nitinol stent wires covered with polycrystalline oxide were chemically etched and then passivated to form amorphous oxide. Excellent metallic-stent corrosion resistance with an amorphous oxide surface was demonstrated in our previous in vitro study. For in vivo validation, we compared the corrosion behavior of different oxide surfaces on various forms of test wires in the abdominal aorta of mongrel dogs using open-circuit potential and cyclic anodic polarization measurements. After conduction, the retrieved test wires were observed under scanning electron microscope. No passivity breakdown was found for wires covered with amorphous oxide, while wires with polycrystalline oxide showed breakdown at potentials between +0.2 to + 0.6 V. It has been proven that severe pitting or crevice corrosion occurred on the surface of polycrystalline oxide, while the surface of amorphous oxide was free of degradations in our experiment. We have demonstrated that this amorphous oxide coating on metallic material provides better corrosion resistance, not only in vitro but also in vivo, and it is superior not only in strength safety but also in medical device biocompatibility.

Antithrombotic and antiplatelet activities of 2-chloro-3-[4-(ethylcarboxy)-phenyl]-amino-1,4-naphthoquinone (NQ12), a newly synthesized 1,4-naphthoquinone derivative

The possibility of NQ12 (2-chloro-3-[4-(ethylcarboxy)-phenyl]-amino-1,4-naphthoquinone) as a novel antithrombotic agent and its mode of action were investigated. The effects of NQ12 on platelet aggregation in human platelet-rich plasma in vitro, in rats ex vivo, and on murine pulmonary thrombosis in vivo, as well as the mode of antithrombotic action were examined. NQ12 potently inhibited ADP-, collagen-, epinephrine-, and calcium ionophore-induced human platelet aggregations in vitro concentration-dependently. NQ12 significantly inhibited rat platelet aggregation in an ex vivo study. NQ12 prevented murine pulmonary thrombosis in a dose-dependent manner. However, NQ12 did not affect coagulation parameters such as activated partial thromboplastin time, prothrombin time, and thrombin time. NQ12 inhibited fibrinogen binding to the platelet surface GPIIb/IIIa receptor, but failed to inhibit binding to the purified GPIIb/IIIa receptor. Thromboxane B(2) formation caused by thrombin or collagen was inhibited significantly by NQ12. The phosphoinositide breakdown induced by thrombin or collagen was inhibited concentration-dependently by NQ12. These results suggest that NQ12 may be a promising antithrombotic agent, and its antithrombotic activity may be due to antiplatelet aggregation activity, which may result from the inhibition of phosphoinositide breakdown and thromboxane A(2) formation.

ICAM-1 (intercellular adhesion molecule-1) gene transfection inhibits lymph node metastasis by human gastric cancer cells

Lymph node metastasis is one of the prognostic factors in gastric cancer. We have previously reported that decreased intercellular adhesion molecule-1 (ICAM-1) expression on cancer cells is associated with lymph node metastasis using a gastric cancer cell. In this study, we transfected ICAM-1 gene into a gastric cancer cell line, 2MLN, and analyzed the effect on lymph node metastasis in vitro and in vivo. A significantly greater amount of peripheral blood mononuclear cells (PBMC) adhered to ICAM-1 transfected 2MLN cells, 2MLN / ICAM cells, than to 2MLN / Vector cells. The lysis of 2MLN / ICAM cells by PBMC was significantly increased compared with that of 2MLN / Vector cells. The tumor growth rate of 2MLN / ICAM cells was significantly decreased in vivo. Lymph node metastases caused by 2MLN / ICAM cells were recognized as being fewer in number and smaller, while many lymph node metastases were caused by 2MLN cells. Histologic findings showed that leukocytes were heavily infiltrated in both the 2MLN / ICAM tumors and metastatic lesions, while only a few leukocytes were observed in the lesions associated with 2MLN cells. The above findings indicate that ICAM-1 gene transduction could prove to be an effective gene therapy for lymph node metastasis of gastric cancer.

Suppressive mechanism of salmosin, a novel disintegrin in B16 melanoma cell metastasis

We have previously reported that salmosin, a novel disintegrin, was isolated from Korean snake (Agkistrodon halys brevicaudus) venom and significantly inhibited solid tumor growth in mice by perturbation of tumor-specific angiogenesis via blocking alphavbeta3 integrin expressed on vascular endothelial cells. In this study, we investigated the functional specificity of salmosin in tumor cell metastasis. Recombinant salmosin expressed in E. coli that has the RGD sequence markedly inhibited both B16F10 melanoma cell adhesion to the extracellular matrix proteins as well as B16F10 melanoma cell invasion through Matrigel-coated filter. The inhibition by salmosin can be caused by blocking integrins expressed on the surface of B16F10 melanoma cells. Salmosin significantly inhibited the proliferation of B16F10 melanoma cells on the plate coated with collagen I in a dose-dependent manner. In vivo B16F10 melanoma experimental metastasis, salmosin showed remarkable significant inhibitory effect on lung tumor colonization in a concentration-dependent manner. These results clearly demonstrate that antimetastatic activity of salmosin resulted from blocking the integrin-mediated adherence and alphavbeta3 integrin-mediated proliferation of the melanoma cells.

Antibody-dependent cytotoxicity mediated by chimeric monoclonal antibody Nd2 and experimental immunotherapy for pancreatic cancer

In a previous study, mouse monoclonal antibody (MoAb) Nd2 (m-Nd2, mouse IgG1) labeled with (131)I exhibited efficacy in in vivo radioimmunotherapy against pancreatic cancer. In this study we prepared mouse / human chimeric antibody Nd2 (c-Nd2, human IgG1) for clinical use and examined whether c-Nd2 induced antibody-dependent cell-mediated cytotoxicity (ADCC). Cytotoxicity to pancreatic cancer (PC) cell lines, including Nd2 antigen-positive (SW1990, RWP-1, Capan-1) and Nd2 antigen-negative (Panc-1, MiaPaca-2, Capan-2) lines, was evaluated by mixed human leukocyte and tumor cell culture (MLTC) at an effector cell to target cell (E / T) ratio of 50 with or without Nd2. Cytotoxicities to SW1990 with no antibody, m-Nd2 and c-Nd2 (1 microg / ml) were 26.7%, 38.0% and 55%, respectively; to RWP-1, 28%, 41% and 70%; to Capan-1, 26%, 30% and 52%; to Panc-1, 24%, 28% and 30%; to MiaPaca-2, 18%, 20% and 27% and to Capan-2, 29. 7%, 35.0% and 40.6%. Cytotoxic capacity during MLTC with c-Nd2 was significantly higher than during MLTC with m-Nd2 or with no antibody. These findings indicated that cytotoxicity to Nd2-positive PC cells during MLTC is induced by ADCC. Intraperitoneal injection of c-Nd2 inhibited the tumor growth of SW1990 xenografted subcutaneously in nude mice and prolonged the survival of nude mice in which SW1990 tumor was transplanted orthotopically at the tail of the pancreas. These findings suggested that, because of its ability to induce ADCC, c-Nd2 may be clinically useful for the immunotherapeutic treatment of pancreatic cancer.

Pattern of deposition of stainless steel welding fume particles inhaled into the respiratory systems of Sprague-Dawley rats exposed to a novel welding fume generating system

In order to investigate occupational diseases related to welding fume exposure, such as nasal septum perforation, pneumoconiosis and manganese intoxication, we built a welding fume exposure system that included a welding fume generator, exposure chamber and fume collector. The fume concentrations in the exposure chamber were monitored every 15 min during a 2-h exposure. Fume (mg/m(3)) concentrations of major metals, including Fe, Mn, Cr, and Ni were found to be consistently maintained. An acute inhalation toxicity study was conducted by exposing male Sprague-Dawley rats to the welding fumes generated in this apparatus by stainless steel arc welding. The rats were exposed in the inhalation chamber to a welding fume with a concentration of 62 mg/m(3) total suspended particulates for 4 h. Animals were sacrificed at 4 h and at 1, 3, 7, 10, and 14 days after exposure. Histopathological examinations were conducted on the animals' upper respiratory tracts, including the nasal pathway and the conducting airway, and on the gas exchange region including the alveolar ducts, alveolar sacs, and alveoli. Diameters of fume particles varied from 0.02 to 0.81 microm and were distributed log normally, with a mean diameter of 0.1 microm and geometric standard deviation of 1.42. Rats exposed to the welding fume for 4 h did not show any significant respiratory system toxicity. The mean particle diameter of 0.1 microm resulted in little adsorption of the welding fume particles in the upper respiratory tract. Particle adsorption took place principally in the lower respiratory tracts, including bronchioles, alveolar ducts, alveolar sacs, and alveoli.

Evaluation of argyrophilic nucleolar organizer regions (AgNORs) in differentiated thyroid carcinoma as an indicator for disease recurrence

Differentiated thyroid carcinoma (DTC) is one of the least aggressive cancers of the human malignancies, however, recurrent disease is occasionally found and is difficult to determine the risk for recurrence only by clinicopathological features. In the present study, we investigated argyrophilic nucleolar organizer regions (AgNORs) score, a well-known indicator for proliferative potential of the cancer cells, in 89 cases of DTC. In tumors with capsular invasion, or with extended contra-lateral lymph node metastasis, AgNORs score was significantly higher than in tumors without them, while was not correlated with age or gender of the patients, nor the histological type of the tumor (papillary or follicular). Disease recurrence was observed in one-third of the patients in high AgNOR score group (scored more than mean value +/- standard deviation) when the patients were divided into four groups according to the AgNOR score, and a significantly higher risk for disease recurrence was demonstrated in those cases with high AgNOR score than cases with lower score. These results clearly indicated the usefulness of AgNOR score in selecting the patients at high risk for disease recurrence. All 5 recurrent cases displayed local recurrence in high AgNOR score group, while 5 of 7 cases with low AgNOR score did in the manner of hematological metastasis. In conclusion, this method was technically simple and accurate giving an exact value in individual cases. Thus, we believe AgNOR score might be clinically applicable as a useful indicator for disease recurrence in DTC.

Neuroendocrine carcinoma of the sigmoid colon: report of a case

Neuroendocrine carcinoma of the colon is a rare entity; however, this type of tumor is known for its aggressive progression and poor prognosis. A case of a 56-year-old Japanese male is presented in this report. A huge, child's head-sized tumor was found to have grown extraluminally on the sigmoid colon with multiple liver metastases. The tumor measured 16.5 x 15 x 8.2 cm in size and weighed 1 300 g. The patient died of hepatic failure due to massive liver metastases 6 months after operation. The pathological findings including an electron microscopic analysis were correlated with those of neuroendocrine carcinoma. We reviewed the English literature, and analyzed 94 cases of neuroendocrine carcinoma which had been reported previously. The nomenclature and definition of this disease still remains somewhat unclear, and not a small population of this disease may thus have been misdiagnosed and treated as other less aggressive entities. The necessity to make an accurate differential diagnosis in such cases is thus emphasized.

Antiplatelet and antithrombotic activities of NQ301, 2-chloro-3-(4-acetophenyl)-amino-1,4-naphthoquinone

The antiplatelet and antithrombotic activities of a newly synthesized NQ301, 2-chloro-3-(4-acetophenyl)-amino-1,4-naphthoquinone, were investigated on human platelet aggregation in vitro and rats ex vivo, and murine pulmonary thrombosis in vivo. NQ301 potently inhibited ADP-, collagen-, epinephrine- and calcium ionophore A23187-induced human platelet aggregation in a concentration-dependent manner in vitro. NQ301 significantly inhibited platelet aggregation in orally administered rats ex vivo. NQ301 prevented death due to pulmonary thrombosis in mice dose-dependently in vivo. NQ301 also showed significant prolongation of tail bleeding time in conscious mice. However, NQ301 did not alter such coagulation parameters as activated partial thromboplastin time, prothrombin time, and thrombin time in human plasma. These results suggest that NQ301 may be a promising antithrombotic agent, and the antithrombotic activity of NQ301 may be due to antiplatelet aggregation activity but not to in vitro anticoagulation.

Evaluation of different methods for cleaning and preparing occlusal fissures

The effectiveness of different methods for cleaning and preparing occlusal fissures before placing sealants was evaluated. Extracted mandibular molars received such treatments as brushing, pumicing, bur preparing, and air abrasion before application of fissure sealants. FluroShield fissure sealant was then applied to the occlusal fissures. Specimens were subjected to thermo-cycling and then immersed in a 10% solution of methylene blue, and finally sectioned. The sections were examined and photographed in a stereomicroscope, and the dye penetration was recorded using a scoring system. The results indicated that only the control (brushing with a dry brush) and the pumicing groups demonstrated dye penetration to the base of the sealant. Teeth prepared with the #1/4 round bur and air abrasion demonstrated a better seal in evaluated fissures. For this study, those three groups (occlusal fissures prepared with the #1/4 round bur and two air abrasion methods), demonstrated significantly better sealing (P < 0.01) than the control group and the other groups tested.

Antithrombotic activities of green tea catechins and (-)-epigallocatechin gallate

The antithrombotic activities and mode of action of green tea catechins (GTC) and (-)-epigallocatechin gallate (EGCG), a major compound of GTC, were investigated. Effects of GTC and EGCG on the murine pulmonary thrombosis in vivo, human platelet aggregation in vitro, and ex vivo, and coagulation parameters were examined. GTC and EGCG prevented death caused by pulmonary thrombosis in mice in vivo in a dose-dependent manner. They significantly prolonged the mouse tail bleeding time of conscious mice. They inhibited adenosine diphosphate- and collagen-induced rat platelet aggregation ex vivo in a dose-dependent manner. GTC and EGCG inhibited ADP-, collagen-, epinephrine-, and calcium ionophore A23187-induced human platelet aggregation in vitro dose dependently. However, they did not change the coagulation parameters such as activated partial thromboplastin time, prothrombin time, and thrombin time using human citrated plasma. These results suggest that GTC and EGCG have the antithrombotic activities and the modes of antithrombotic action may be due to the antiplatelet activities, but not to anticoagulation activities.

Vascular endothelial growth factor expression in preoperative biopsy specimens correlates with disease recurrence in patients with early gastric carcinoma

BACKGROUND

Recently many studies have demonstrated that the degree of tumor angiogenesis is related to the aggressiveness of the tumor and clinical outcome. Vascular endothelial growth factor (VEGF) is a well characterized inducer of angiogenesis. In this study, the authors investigated the prognostic significance of VEGF expression in patients with early gastric carcinoma together with p53 gene abnormality and tumor cell proliferation.

METHODS

One hundred ninety-five endoscopically biopsied specimens obtained preoperatively from patients with early gastric carcinoma were studied immunohistochemically.

RESULTS

According to conventional clinicopathologic factors, submucosal invasion, lymph node metastases, and tumor size were associated significantly with the incidence of disease recurrence. According to conventional biologic factors, VEGF expression was observed more frequently in patients with disease recurrence compared with those without disease recurrence whereas neither p53 abnormality nor tumor cell proliferation were correlated with prognosis. Moreover, multivariate analysis indicated that VEGF expression (as well as submucosal invasion and lymph node metastases) is an independent predictor of disease recurrence.

CONCLUSIONS

The results of the current study show that VEGF expression may be a useful prognostic factor for patients with early gastric carcinoma.

Vascular endothelial growth factor expression in preoperative biopsy specimens correlates with disease recurrence in patients with early gastric carcinoma

BACKGROUND

Recently many studies have demonstrated that the degree of tumor angiogenesis is related to the aggressiveness of the tumor and clinical outcome. Vascular endothelial growth factor (VEGF) is a well characterized inducer of angiogenesis. In this study, the authors investigated the prognostic significance of VEGF expression in patients with early gastric carcinoma together with p53 gene abnormality and tumor cell proliferation.

METHODS

One hundred ninety-five endoscopically biopsied specimens obtained preoperatively from patients with early gastric carcinoma were studied immunohistochemically.

RESULTS

According to conventional clinicopathologic factors, submucosal invasion, lymph node metastases, and tumor size were associated significantly with the incidence of disease recurrence. According to conventional biologic factors, VEGF expression was observed more frequently in patients with disease recurrence compared with those without disease recurrence whereas neither p53 abnormality nor tumor cell proliferation were correlated with prognosis. Moreover, multivariate analysis indicated that VEGF expression (as well as submucosal invasion and lymph node metastases) is an independent predictor of disease recurrence.

CONCLUSIONS

The results of the current study show that VEGF expression may be a useful prognostic factor for patients with early gastric carcinoma.