The use of polyethylenimine-DNA to topically deliver hTERT to promote hair growth.

The present study investigates the efficacy of polyethylenimine (PEI)-DNA complex that expressed human telomerase reverse transcriptase (hTERT) to transfect hair follicle stem cells and produce sufficient hTERT to stimulate hair growth. Transfection with pLC-hTERT-DNA-PEI complex (D+P group) in vitro induced expression of proliferating cell nuclear antigen in 35.8% of the purified stem cell population, suggesting enhanced cell proliferation. In vivo transfection efficiency of rat dorsal skin was determined by staining for ß-gal activity. Cells positive for ß-gal were located in the bulge region and dermal sheath of hair follicles. The follicles in the hTERT-transfected region entered anagenon day 15 after transfection, whereas non-transfected (Neg) controls remained in telogen. The similar effect was observed in 50-day-old rat dorsal skin. D+P group displayed a specific expression of hTERT and sufficient to initiate a transition to the anagen phase and promote new hair synthesis 18 days after the transfection. hTERT promoted follicle neogenesis following wounding. In all, 60 days after wounding, tissues of the D+P group showed more newly regenerating hair follicles (83±52 regenerated follicles per rat) in contrast to control group tissues (15±15 regenerated follicles per rat). These studies provide a potential approach for gene therapy of skin disease.

Differential effects of high MUFA with high or low P/S ratio (polyunsaturated to saturated fatty acids) on improving hepatic lipolytic enzymes and mediating PPARγ related with lipoprotein lipase and hormone-sensitive lipase of white adipose tissue in diet-induced obese hamster.

OBJECTIVES: The aim of this study was to assess the relationship between high monounsaturated fatty acids (MUFAs) with different levels of polyunsaturated-to-saturated fatty acid (P/S) ratios and body fat loss in diet-induced obesity (DIO) models. DESIGN: Male Golden Syrian hamsters were randomly assigned to the control group (n=12) and obesity group (n=24) for 4 weeks of the high-fat DIO period; afterward, six hamsters from each group were killed. The remaining control hamsters were still fed a low-fat diet. For an additional 8 weeks, the remaining obesity hamsters were switched to a low-fat diet and subdivided into three subgroups (n=6/group): the obesity-control (ObC) group, high MUFA with high P/S ratio oil (HMHR) group and olive oil (OO) group. Serum insulin and leptin concentrations were measured, and hepatic fatty acid metabolic enzymes and adipose differentiation markers were determined using enzyme activities analysis, western blot and semiquantification reverse-transcription PCR. RESULTS: No difference was observed in the mean energy intake through all study periods. After the DIO period, the obesity group increased in weight gain and epididymal fat weight compared with the control group. DIO hamsters in the HMLR group had significant reductions in white adipose tissue deposition and plasma leptin levels, suppression in adipose peroxisome proliferator-activated receptor-γ (PPARγ) and lipoprotein lipase (LPL) mRNA expressions and increases in hepatic acyl-CoA oxidase and carnitine palmitoyltransferase-I activities and mRNA levels compared with those in the ObC group. The HMHR group had upregulated phosphorylation of hormone-sensitive lipase (HSL) relative to total HSL protein levels compared with the OO group. However, the OO group had significantly elevated hepatic de novo lipogenesis compared with the HMHR group. CONCLUSIONS: HMHR seemed to be beneficial in depleting white adipose tissue accumulation by decreasing adipose PPARγ and LPL mRNA expressions and mediating phosphorylation of HSL, and by improving hepatic lipolytic enzyme activities and mRNA expressions involved in ß-oxidation in DIO hamsters.

Clinical trial: a multicentre, randomized, double-blind, placebo-controlled, dose-finding, phase II study of subcutaneous interferon-beta-la in moderately active ulcerative colitis.

BACKGROUND: Ulcerative colitis (UC) pathophysiology is characterized by an imbalance between pro- and anti-inflammatory cytokines. Interferon (IFN)-beta-1a has potent immunoregulatory properties, including stimulation of host defence mechanisms and thus represents a potential treatment. AIM: To extend pilot data and identify a suitable dose of IFN-beta-1a to achieve endoscopically confirmed remission (ECR) in patients with moderately active UC and to evaluate safety. METHODS: In this multicentre, double-blind, placebo-controlled trial, adults with moderately active UC were randomized to IFN-beta-1a 44 or 66 microg, or placebo, subcutaneously three times weekly for 8 weeks, with a 4-week follow-up. RESULTS: Endoscopically-confirmed remission was observed in 23.4% [95% confidence interval (CI): 13.8-35.7] of placebo patients, 29.2% (95% CI: 18.6-41.8) of the IFN-beta-la 44 microg group and 20.0% (950% CI: 11.1-31.8) of the 66 microg group (P = 0.45). Improvements with IFN-beta-1a 44 microg were greater than with placebo for most secondary efficacy outcomes, although significance was not achieved. Placebo response rates were higher than expected from previous trials. Adverse events were similar to the known safety profile of IFN treatment. CONCLUSIONS: Interferon-beta-1a was generally well tolerated at the doses tested, but a significant therapeutic benefit in patients with UC was not observed.

Epidemiology of Enterobius vermicularis infection among elementary school children in Hualien, Taiwan from 2007 to 2012.

Enterobius vermicularis is the most common human intestinal parasite, and its control among school children is an important public health issue. The objective of this study was to document the present situation of E. vermicularis infection in school children in Hualien. The administrative divisions in Hualien county include 13 districts (3 in a mountainous area, 10 in a rural/urban area). Between 2007 and 2012, a total of 41,191 children in 13 districts in Hualien were examined using consecutive 2-day adhesive cellophane paper perianal swabs. Our results showed Enterobius egg-positive infection rates of 5.79% (452/7,089) in 2007, 6.25% (457/7,312) in 2008, 5.37% (385/7,173) in 2009, 4.98% (330/6,804) in 2010, 4.91% (301/6,133) in 2011, and 4.68% (279/5,960) in 2012. Compared to the previously reported national average in Taiwan (range, 1.53-2.23%), the prevalence of E. vermicularis in Hualien is relatively high. The infection rates were 7.55-29.10% in mountainous areas and 0.50- 12.43% in rural/urban areas. All first and fourth grade students in elementary schools in Hualien were selected as study participants. The average infection rate of the first grade students (6.71%) was higher than that of the fourth grade students (4.23%). These results indicate that enterobiasis remains an important parasitic disease among school children in Hualien, especially those in mountainous areas.

Relationship between dietary intake, lipoproteins, and apolipoproteins in Taipei and Framingham.

To determine whether the lower rates of heart disease in Taiwan than in the United States could be related to associations between plasma lipoproteins and dietary intake, we assessed these indexes in 423 adults in Taipei matched with 420 adults in Framingham, MA. Concentrations of LDL cholesterol were 14% lower, HDL cholesterol 9% higher, and LDL cholesterol: HDL cholesterol 27% lower in Taipei than in Framingham. Dietary intakes of total fat (34%), saturated fatty acids, and cholesterol (338 mg) were, respectively, 16%, 41%, and 19% lower in Taipei men, whereas polyunsaturated fatty acid intake was 89% higher than in Framingham men. Similar differences were seen for women except for total fat and cholesterol intakes, which were similar. From stepwise analyses of all subjects, we observed significant associations of lower LDL cholesterol: HDL cholesterol with higher polyunsaturated fatty acid intakes and lower body mass indexes in both men and women. Our data indicate that the more favorable lipoprotein profiles observed in Taipei subjects may be partly due to differences in type of dietary fat consumption as well as in body mass index.

A theoretical study of cylindrical ultrasound transducers for intracavitary hyperthermia.

PURPOSE: The purpose of this paper was to examine the heating patterns and penetration depth when a cylindrical ultrasound transducer is employed for intracavitary hyperthermia treatments. METHODS AND MATERIALS: The present study employs a simulation program based on a simplified power deposition model for infinitely long cylindrical ultrasound transducers. The ultrasound power in the tissue is assumed to be exponentially attenuated according to the penetration depth of the ultrasound beam, and a uniform attenuation for the entire treatment region is also assumed. The distribution of specific absorption rate (SAR) ratio (the ratio of SAR for a point within the tissue to that for a specific point on the cavity surface) is used to determine the heating pattern for a set of given parameters. The parameters considered are the ultrasound attenuation in the tissue, the cavity size, and the transducer eccentricity. RESULTS: Simulation results show that the ultrasound attenuation in the tissue, the cavity size, and the transducer eccentricity are the most influential parameters for the distribution of SAR ratio. A low frequency transducer located in a large cavity can produce a much better penetration. The cavity size is the major parameter affecting the penetration depth for a small cavity size, such as interstitial hyperthermia. The heating pattern can also be dramatically changed by the transducer eccentricity and radiating sector. In addition, for a finite length of cylindrical transducer, lower SAR ratio appears in the regions near the applicator's edges. CONCLUSION: The distribution of SAR ratio indicates the relationship between the treatable region and the parameters if an appropriate threshold of SAR ratio is taken. The findings of the present study comprehend whether or not a tumor is treatable, as well as select the optimal driving frequency, the appropriate cavity size, and the eccentricity of a cylindrical transducer for a specific treatment.

Treatable domain and optimal frequency for brain tumors during ultrasound hyperthermia.

PURPOSE: To examine the optimal ultrasound frequency and the treatable domain determined by the tumor size and tumor depth when an external ultrasound heating system is employed for the brain tumor hyperthermia. METHODS AND MATERIALS: This work employs a simplified model of a scanned ultrasound transducer power deposition (a cone with convergent/divergent shape) and a search algorithm to investigate the optimal frequency and the treatable domain. The distributions of temperature and SAR (specific absorption rate) ratio are used to determine the appropriateness of the acoustic window size and the input power level for a yielded set of tumor conditions. The factors considered are the acoustic window size, tumor size and depth, ultrasound frequency, and the acoustic absorption of the post-target bone behind the tumor. RESULTS: Simulation results demonstrate that the optimal frequency depends on the tumor depth and the acoustic absorption of the post-target bone. However, it is almost independent of the acoustic window size. The optimal frequency shifts to a higher level for a deeper tumor heating to reduce the effect of the high acoustic absorption of post-target bone. Moreover, the treatable domain is proportional to the acoustic window size and related to the ultrasound frequency. CONCLUSION: It may not be possible to deliver appropriate ultrasonic energy to heat a brain tumor without overheating the normal brain tissue and/or the post-target bone under the constraints of the available acoustic window size for the ultrasonic beam, ultrasonic attenuation of brain tissue, high absorption of post-target bone, and high blood perfusion rate. The results of this study can be a guideline for designing an optimal ultrasound heating system, arranging the transducers, and implementing further treatment planning for the brain tumor hyperthermia.

Relationship of body fat distribution with cardiovascular risk factors in healthy Chinese.

The relationships between six body girths (shoulder, midarm, waist, hip, thigh, and calf) and cardiovascular risk factors (systolic and diastolic blood pressures and glucose, triglyceride, lipoprotein cholesterol, and apolipoprotein levels) were examined in 407 healthy Chinese urban workers in Taipei, Taiwan who were between 40 to 59 years old. Canonical correlation analysis revealed significant associations of upper body adiposity (shoulder, midarm, and waist girths) with cardiovascular risk factors in all subgroups assessed: men, premenopausal women, and postmenopausal women. Waist girth and hip girth were consistent and important variables, and weighted in the opposite direction. Waist-hip ratio (WHR) was the best descriptor of centralized adiposity. Centralized fat distribution was positively associated with blood pressure and glucose, triglyceride, and apolipoprotein (apo) B levels, and negatively associated with high-density-lipoprotein (HDL) cholesterol and apo A-I levels in this population. Body fat distribution had an effect independent of body mass index and accounted for some of the differences in triglyceride, HDL cholesterol, apo A-I, and apo B concentrations among men, premenopausal women, and postmenopausal women. Our findings in a Chinese population are similar to data from other studies in Western populations, and are consistent with the hypothesis that centralized adiposity is related to cardiovascular risk factors independent of general obesity.

Early reconstruction of pharynx and esophagus following corrosive injury with radial forearm flap in preparation for colon interposition.

In 24 patients, corrosive injuries involving the floor of the mouth, the pharynx, and the esophagus were repaired in two stages using a combined free forearm flap and colon for functional restoration of the alimentary tract. The results were satisfactory. Morbidity was decreased, complications were minimal, and there were no failures. In the first stage, early reconstruction with a forearm flap for the oral floor, the pharynx, and the cervical esophagus can be done safely 3 months after the original injury when the acute inflammation of the tissue has disappeared. The forearm flap is thin and pliable, and has a good blood supply for primary healing without failure or stricture. Dysphagia is eliminated because food passes down by gravity. There is no constriction or hyperperistalsis of the colon, both of which are occasionally seen with the traditional colon interposition. In the second stage, the traditional method is used to finish the reconstruction of the remainder of the esophagus.

Transatrial membranotomy for Budd-Chiari syndrome.

In a 7-year period, transatrial membranotomy was performed in 11 patients with membranous obstruction of the inferior vena cava. There were 5 men and 6 women, ranging in age from 23 to 53 years. Clinical symptoms included jaundice in 4 patients, hepatomegaly in 4, leg edema or varicose veins in 10, and venous collaterals over the abdominal and chest wall in all 11 patients. Transatrial membranotomy was performed through a median sternotomy in all patients. When inferior vena cava venography revealed that the obstruction was accompanied by long segmental thrombosis, additional dilation was performed with a Hegar dilator. There was no surgical mortality. Early operative complications included pulmonary embolism in 2 patients and bleeding requiring reoperation in 1. In a mean follow-up period of 30.6 months (range, 2 to 88 months), 9 patients had no symptoms, transient pericardial constriction developed in 1 patient and resolved 1 month later, and restenosis of the inferior vena cava developed in another patient 1 year after the first operation. This latter patient received a second transatrial membranotomy followed by percutaneous balloon angioplasty of the inferior vena cava, with a satisfactory result at 8 months follow-up. We conclude that transatrial membranotomy is an effective and safe procedure for patients with membranous obstruction of the inferior vena cava.

Traumatic asphyxia.

During a 5-year period, we treated 14 cases of traumatic asphyxia. There were 12 male and 2 female patients ranging in age from 2 to 32 years. Most suffered crushing injuries at work or were run over by motor vehicles. Mild to severe cervicofacial cyanosis and petechiae developed in all patients. A fear response was reported by 12 of the patients. Subconjunctival hemorrhage was also found in 12 patients. Nine patients had tachypnea and 7 complained of dyspnea. Most of the patients suffered some associated injuries including 8 head injuries, 7 pulmonary contusions, and 6 cases of blunt abdominal trauma. Less-associated injuries were rib fractures, brachial and radial nerve injuries, hemothorax, and pneumothorax. The hospital stay ranged from 4 to 28 days (mean, 14 days) and follow-up from 10 to 60 months (mean, 32 months). Treatment for traumatic asphyxia included measurement of arterial blood gases, oxygen supplementation, and intubation with mechanical ventilation. The patients' recovery conditions were relative to the severity of injury and the associated injuries.

Intrapericardial pheochromocytoma.

In a 34-year-old man with hypertension and increased urinary catecholamine excretion for 12 years, an m-[131I]iodobenzylguanidine scan and chest computed tomography located an intrapericardial pheochromocytoma in the left atrium. The tumor was excised through a left thoracotomy with cardiopulmonary bypass and circulatory arrest. At 34-month follow-up, blood pressure and urine catecholamine levels were normal. In the 15 cases of intrapericardial pheochromocytoma treated by resection reported in the literature, all 11 survivors were symptom-free except 1 who had residual left atrial tumor and multiple skeletal metastatic lesions. Computed tomography directed by the m-[131I]iodobenzylguanidine scan can be used for detailed location of the tumor. Appropriate surgical approach and use of cardiopulmonary bypass are critical in the resection of these highly vascular tumors.

Theoretical study of temperature elevation at muscle/bone interface during ultrasound hyperthermia.

This paper examines the distributions of the SAR (specific absorption rate) ratio and temperature elevation when an ultrasound beam propagates through the interface of muscle and bone. This interface is regarded as a flat boundary to partition the energy of the ultrasound beam, and the analytical solution of temperature distribution is based on the steady-state bio-heat transfer equation. The parameters considered are the incident angle of ultrasound beam, the ultrasound frequency, the acoustic attenuation coefficients of refracted longitudinal and shear waves in bone, and the blood perfusion in muscle. The results show that the peak of the SAR ratio is always at the interface of muscle and bone, while the peak of temperature is located in the bone region beyond the interface. A muscle with lower perfusion or a bone with higher acoustic attenuation results in the shifting of the temperature peak closer to the interface. It is more difficult to heat a higher perfused muscle in front of a bone using a lower frequency ultrasound since the temperature elevation for bone relative to muscle is greater.

Specific absorption rate ratio patterns of cylindrical ultrasound transducers for breast tumors.

The purpose of this paper is to examine the optimal driving frequency and to configure the ultrasound energy deposition schema for a various size and location of breast tissues when a portion or the entire cylindrical ultrasound transducer is employed for breast hyperthermia treatments. This work employs a computer simulation program based on an ideal ultrasound power deposition from a cylindrical transducer. The ultrasound power within the breast is assumed to be exponentially attenuated according to the penetration depth of the ultrasound beam and a uniform absorption for the entire breast is also assumed. The distribution of the specific absorption rate (SAR) ratio is employed to determine the heating pattern of a set of given parameters. The control parameters considered are the ultrasound frequency in the breast tissue, the active portion of cylindrical transducer, and the shifting distance between the central axes of the breast and the transducer. The effect of the breast size on the SAR ratio is also considered. Simulation results demonstrate that the breast size, the ultrasound frequency in breast tissue, the shifting distance, and the active portion of the cylindrical transducer are the potential parameters for influencing the distribution of the SAR ratio. High frequencies should be used for the superficial heating treatments and the active portion of the transducer can be changed to obtain a region with an appropriate SAR ratio to cover the treatment region. Low frequencies are used for deep heating treatments and the region of the high SAR ratio can be moved by shifting the transducer and its pattern is varied with the transducer's active portion. The distribution of the SAR ratio indicates the domain of treatable tumor size and tumor depth for a given set of parameters (driving frequency, shifting distance and active portion of the transducer, as well as breast diameter). Findings of this study can be used to know whether or not the tumor is treatable as well as to select the optimal driving frequency and the appropriate active portion of the cylindrical transducer for a treatment, and hopefully to design an appropriate cylindrical ultrasound heating system for breast tumors.

Relationship between acoustic aperture size and tumor conditions for external ultrasound hyperthermia.

External ultrasound hyperthermia is a very flexible modality for heating deep-seated tumors due to its deep penetration and focusing ability. However, under the constraints of the available acoustic aperture size for the ultrasonic beam, ultrasonic attenuation, as well as other anatomic properties, it may not be able to deliver sufficient ultrasonic energy to heat a large tumor located in a deep region without overheating the normal tissue between the tumor and the aperture. In this work, we employ a simulation program based on the steady-state bioheat transfer equation and an ideal ultrasound power deposition (a cone with convergent/divergent shape) to examine the relationship between the minimal diameter of the acoustic aperture and the tumor conditions. Tissue temperatures are used to determine the appropriate aperture diameter and the input power level for a given set of tumor conditions. Due to the assumed central axis symmetry of the power intensity deposition and anatomic properties, a two-dimensional (r-z) simulation program is utilized. Factors determining the acoustic aperture diameter and the input power level considered here are the tumor size, tumor depth, ultrasonic attenuation in tissue, blood perfusion, and temperature of the surface cooling water. Simulation results demonstrate that tumor size, tumor depth, and ultrasonic attenuation are major factors affecting the aperture diameter of the ultrasonic beam to obtain an appropriate temperature distribution, while blood perfusion and the temperature of the surface cooling water are the minor factors. Plots of the effects of these factors can be used as the guideline for designing an optimal ultrasound heating system, arranging the transducers, and planning further treatments.

Self-tuning fuzzy logic control for ultrasound hyperthermia with reference temperature based on objective functions.

The purpose of this paper is to develop and evaluate a self-tuning fuzzy logic controller for a scanned focused ultrasound hyperthermia system with the reference temperature (Tr) determined from objective functions. This work employs simulation programs to develop the power deposition for the scanned focused ultrasound system and to solve the responses of temperature profiles based on the transient bioheat transfer equation. A fuzzy logic control algorithm is employed to determine the output power level for the heating system and an observer for blood perfusion variation is used to enhance the capability of the controller to adjust the required output power level for the treatment due to the drastic change of the blood perfusion. The reference temperature (Tr) for the controller is based on objective functions to tune its value during the heating process, while a control temperature (Tc) from the thermosensors located in the tumor region is used as the input for the controller. The objective function based on the entire temperature profile is used to evaluate the appropriateness of the heating temperature distribution for a time-variational blood perfusion. Simulation results demonstrate that the tumor region can be rapidly heated to the desired temperature level and maintained at that level despite blood perfusion variation. The resulting temperature profile, the objective function, and the output power level are related to the magnitude of blood perfusion, but are almost independent of the Tc location and the initial setting value of Tr. The fuzzy logic control algorithm with Tr determined from objective functions can be used for controlling the entire temperature distribution through a single control temperature, and the combination of control and optimization allows appropriate temperature fields to be created during the entire heating process. The control algorithm does not require the accurate prior knowledge of the locations of the thermosensors and the appropriate setting value for Tr.

Optimal configuration of multiple-focused ultrasound transducers for external hyperthermia.

External ultrasound hyperthermia is considered to be a very flexible modality for heating deep-seated tumors owing to its penetration and focusing ability. However, using this flexibility requires that many complicated, interacting decisions be made to obtain optimal treatment. This paper presents the feasibility of arranging multiple-focused ultrasound transducers to produce an appropriate heating pattern for a specific treatment, based on the optimal scan parameters obtained from an optimization algorithm. The variable scan parameters of the heating system optimized are the transducer tilt and rotation angles, focal depth, scan radius, and output acoustical power. After obtaining the optimal scan parameters, multiple transducers are systematically arranged according to these scan parameters. Three-dimensional ultrasound power deposition and temperature distribution for a specific treatment are calculated for this multiple ultrasound transducer system. A more uniform temperature distribution in the treatment region for a large, highly perfused tumor can be achieved by scanning the system with respect to the central scan axis and/or swinging the transducers inwards and outwards. The maximum heating depth of focused ultrasound transducers used in this heating system is also studied. Simulation results demonstrate that the optimal arrangement of this multiple-focused ultrasound transducer system is highly promising for heating deep, large, and highly perfused tumors.

Estimation of metal and organochlorine pesticide exposures and potential health threat by consumption of oysters in Taiwan.

Pollutant concentrations detected in oysters from 12 different culture areas of Taiwan (especially for the Hsiangshan area and the Machu Islands) from 1991-98 were evaluated to investigate potential carcinogenic (inorganic As and organochlorine pesticides) and non-carcinogenic (Cu, Zn, Cd and inorganic As) risk to the public from ingestion of the oysters. The highest geometric mean (GM) Cu and Zn concentrations of 1108 (range 113-2806) and 1567 (range 303-3593) microg/g dry weight were obtained in oysters from the Hsiangshan coastal area. The maximum GM Cd and As concentrations of 6.82 and 19.3 microg/g dry weight were found in oysters from the Machu Islands area. The p,p'-DDE values range from not detectable in Penghu Islands' oysters to 164 ng/g dry weight in Machu Islands' oysters. The highest tDDT (sum of p,p'-DDE, p,p'-DDD and p,p'-DDT) concentrations of 337 and 340 ng/g dry weight were found in oysters from Kimmen and Machu Islands, respectively. A calculated target hazard quotient (THQ; daily intake/reference dose) of 11.4 (based on 139 g oysters/day) for Cu caused by consuming oysters from the Hsiangshan area is higher than that from other areas (range 0.124-5.95). The highest average Cu intake from Hsiangshan's oysters for individuals is 11.4 times (i.e. THQ=11.4) more than that of reference dose (40 microg/kg/day). However, the maximum THQ values for Cd and As caused by consuming oysters collected from the Machu Islands were 5.57 and 2.63 for Cd and As, respectively. Generally, the results of THQ showed that if only the maximally exposed individuals were considered, the value of 65.4% for oyster was higher than 1.0 in comparison with reference dose. All cancer risk estimates for inorganic As from consuming oysters were higher than 10(-6) (range from 128x10(-6) to 509x10(-6) for maximally exposed individuals and range from 17.1x10(-6) to 68.0x10(-6) for typically exposed individuals, respectively); that is the risk of the lower end of the range of acceptable risk. The highest risk estimate for inorganic As was 509x10(-6) for consumption of oysters by Machu Islands' residents. The lifetime cancer risks of 19.0x10(-6) for tDDT by consuming oysters from the Machu Islands was higher than those from the Penghu Islands (0.37x10(-6)). Therefore, the sum of lifetime cancer risks for tDDT and inorganic As had the highest risks (total risk=528x10(-6)) of consuming oysters from the Machu Islands. Furthermore, a 10(-6) upper limit on lifetime risk as the health protection standard would require maximum oyster consumption rates of approximately 0.26 g/day.

Endoscopic resection of gastrointestinal submucosal tumors.

BACKGROUND/AIMS: The occurrence of submucosal tumors in the gastrointestinal tract is not infrequent. According to endoscopic pictures, submucosal tumors can usually be diagnosed without difficulty. However, even with the aid of endoscopic ultrasound, a definite diagnosis is not possible without histological results. Before endoscopy became available, the treatment strategy for gastrointestinal submucosal tumors was either surgery or observation. Due to advances in scientific technology, endoscopic treatment of gastrointestinal submucosal tumors has become increasingly popular. In reviewing the literature, we found that only case reports or small series reports detailing specific tumors in specific locations existed previously. METHODOLOGY: Endoscopic resection for 12 gastrointestinal submucosal tumors in 11 patients has been successfully performed in our hospital during the past three years. RESULTS: The group included 5 men and 6 women, ranging in age from 28 to 78 years. The locations of the tumors consisted of 1 in the esophagus, 2 in the stomach, 1 in the jejunum, 5 in the colon and 3 in the rectum. Histological results showed 3 lipomas, 3 carcinoids, 2 leiomyomas, 1 ganglioneuromatous polyp, 1 hemangioma, 1 inflammatory fibroid polyp and 1 myomatous hyperplasia. Bleeding complications occurred in only 2 cases. One stopped spontaneously and the other stopped after epinephrine and sclerosant injection. Only 1 case required a two-step resection in order to avoid perforation. No tumor recurrence was noted during the follow-up period, which ranged from 2 months to 3 years. CONCLUSIONS: In suitable cases, endoscopic resection of gastrointestinal submucosal tumors can be a safe and valuable method for treating symptomatic tumors and obtaining histological diagnosis of the submucosal tumors.

Determination of erythrocyte glutathione peroxidase activity and its reference range in Chinese adults.

A method to assess selenium status of the body by measuring glutathione peroxidase activity in erythrocytes was studied. Reaction was measured by continuous monitoring of the decrease of NADPH at 340 nm. The erythrocyte glutathione peroxidase activity was determined at 37 degrees C, pH 7.5 by using one of the substrates, t-butyl hydroperoxide, to initiate the reaction, and using glutathione reductase as the coupling enzyme. The Km of the enzyme for glutathione and t-butyl hydroperoxide were determined to be 1.8 mM and 238 microM, respectively. The enzyme was stable at -20 degrees C or -70 degrees C for at least 5 months, and for at least 2 months when stored at 4 degrees C. The within-run and between-run coefficients of variation for this method were 3.3-4.9% and 3.0-7.1%, respectively. The test was linear up to 100 U/g hemoglobin, and had a sensitivity of 0.002 delta A/min at 3 U/L. The reference range of erythrocyte glutathione peroxidase in Chinese adults was estimated to be 28.6-87.8 U/g hemoglobin (n = 84), without a significant difference in the results between males and females.