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1.
Trop Biomed ; 34(1): 143-149, 2017 Mar 01.
Article in English | MEDLINE | ID: mdl-33592992

ABSTRACT

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.

2.
Tropical Biomedicine ; : 143-149, 2017.
Article in English | WPRIM (Western Pacific) | ID: wpr-630974

ABSTRACT

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.

3.
Gene Ther ; 19(1): 86-93, 2012 Jan.
Article in English | MEDLINE | ID: mdl-21593794

ABSTRACT

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.


Subject(s)
DNA/administration & dosage , Gene Transfer Techniques , Hair Follicle/growth & development , Polyethyleneimine/therapeutic use , Regeneration , Telomerase/administration & dosage , Animals , Cell Proliferation , Cell Survival , DNA/metabolism , DNA/therapeutic use , Flow Cytometry , Genetic Therapy , Hair Follicle/injuries , Hair Follicle/metabolism , Hair Follicle/physiology , Humans , Keratinocytes/cytology , Keratinocytes/metabolism , Mice , Plasmids/genetics , Plasmids/metabolism , Polyethyleneimine/metabolism , Proliferating Cell Nuclear Antigen/metabolism , Rats , Rats, Wistar , Stem Cells/metabolism , Swiss 3T3 Cells , Telomerase/genetics , Telomerase/metabolism , Time Factors , Transfection , Wounds and Injuries/therapy , beta-Galactosidase/metabolism
4.
Int J Obes (Lond) ; 34(11): 1608-17, 2010 Nov.
Article in English | MEDLINE | ID: mdl-20458324

ABSTRACT

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.


Subject(s)
Adipose Tissue, White/metabolism , Adipose Tissue/physiology , Dietary Fats/administration & dosage , Lipoprotein Lipase/metabolism , Obesity/physiopathology , PPAR gamma/metabolism , Animals , Cricetinae , Energy Intake , Fatty Acids/administration & dosage , Fatty Acids, Monounsaturated/administration & dosage , Fatty Acids, Unsaturated/administration & dosage , Immunohistochemistry , Lipid Metabolism , Male , Mesocricetus , Obesity/metabolism , Olive Oil , PPAR gamma/pharmacology , Plant Oils/administration & dosage , Random Allocation , Sterol Esterase/metabolism
5.
J Med Eng Technol ; 33(3): 209-13, 2009.
Article in English | MEDLINE | ID: mdl-19340691

ABSTRACT

Cutaneous electrogastrogram (EGG) recording offers the benefit of non-invasive gastrointestinal diagnosis. With long-term ambulatory recording of signals, researchers and clinicians could have more opportunities to investigate and analyse paroxysmal or acute symptoms. A portable EGG system based on a digital voice recorder (DVR) is designed for long-term recording of cutaneous EGG signals. The system consists of electrodes, an EGG amplifier, a modulator, and a DVR. Online monitoring and off-line acquisition of EGG are handled by software. A special design employing an integrated timer circuit is used to modulate the EGG frequency to meet the input requirements of the DVR. This approach involves low supply voltage and low power consumption. Software demodulation is used to simplify the complexity of the system, and is helpful in reducing the size of the portable device. By using surface-mount devices (SMD) and a low-power design, the system is robust, compact, and suitable for long-term portable recording. As a result, researchers can record an ambulatory EGG signal by means of the proposed circuits in conjunction with an up-to-date voice-recording device.


Subject(s)
Data Collection/instrumentation , Electrodiagnosis/instrumentation , Gastrointestinal Diseases/diagnosis , Monitoring, Ambulatory/instrumentation , Signal Processing, Computer-Assisted/instrumentation , Acute Disease , Electrodes , Equipment Design , Humans , Software
6.
Aliment Pharmacol Ther ; 28(6): 758-67, 2008 Sep 15.
Article in English | MEDLINE | ID: mdl-19145731

ABSTRACT

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.


Subject(s)
Colitis, Ulcerative/drug therapy , Immunologic Factors/therapeutic use , Interferon-beta/therapeutic use , Adult , Colitis, Ulcerative/pathology , Dose-Response Relationship, Drug , Double-Blind Method , Drug-Related Side Effects and Adverse Reactions/epidemiology , Endoscopy, Gastrointestinal , Europe/epidemiology , Female , Humans , Injections, Subcutaneous , Male , Placebos , Quality of Life , Remission Induction , Severity of Illness Index , Treatment Outcome
7.
Int J Hyperthermia ; 23(4): 371-80, 2007 Jun.
Article in English | MEDLINE | ID: mdl-17558736

ABSTRACT

PURPOSE: Low-intensity ultrasound irradiation is a potential method for suppressing cancer cell proliferation, inducing apoptosis and delivering specific cytotoxic genes or drugs into tumors topographically in future cancer therapies. However, ultrasound attenuates rapidly in tissue and produces heat. Pulsed ultrasound is frequently used to minimize pain and possible thermal damage to the surrounding normal tissue during therapy, since it results in smaller temperature increases. This study compared three pulsed-ultrasound strategies for destroying cancer cells, measuring their induced temperature increases to determine the optimal pulsing parameters. MATERIALS AND METHODS: We performed three types of experiment, involving ultrasound with (1) a fixed duty cycle of 50% with variable on- and off-times, (2) a fixed off-time with variable on-times, and (3) a fixed on-time with variable off-times. RESULTS: The results show that for different types of cultured cells (HeLa, HT-29, Ca9-22 and fibroblast) exposed to ultrasound of the same frequency (1 MHz) and energy, long pulses combined with off-times that are 5-10 times longer (on-/-off-times pairs of 5/25, 25/250, or 250/2500 ms/ms) cause significant cell destruction whilst avoiding temperature increases of more than 1.5 degrees C. Furthermore, the correlation between the temperature increase and the percentage of surviving cells is low. CONCLUSIONS: Pulsed ultrasound with a long on-time and an even longer off-time exerts a high cytotoxic effect but a smaller temperature increase compared with non-pulsed ultrasound. This indicates that the cytotoxic effects observed in the current study were not purely due to the thermal effects of the ultrasound.


Subject(s)
Fibroblasts/radiation effects , Hot Temperature , Tumor Cells, Cultured/radiation effects , Ultrasonic Therapy , HT29 Cells , HeLa Cells , Humans , Time Factors
8.
Med Phys ; 27(5): 1131-40, 2000 May.
Article in English | MEDLINE | ID: mdl-10841420

ABSTRACT

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.


Subject(s)
Ultrasonic Therapy/methods , Acoustics , Biomedical Engineering , Biophysical Phenomena , Biophysics , Bone and Bones/physiopathology , Humans , Models, Biological , Muscles/physiopathology , Neoplasms/physiopathology , Neoplasms/therapy , Temperature
9.
Int J Radiat Oncol Biol Phys ; 46(5): 1329-36, 2000 Mar 15.
Article in English | MEDLINE | ID: mdl-10725647

ABSTRACT

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.


Subject(s)
Computer Simulation , Hyperthermia, Induced/instrumentation , Transducers , Ultrasonic Therapy/instrumentation , Algorithms , Equipment Design , Hyperthermia, Induced/methods , Temperature , Ultrasonic Therapy/methods
10.
Int J Radiat Oncol Biol Phys ; 46(1): 239-47, 2000 Jan 01.
Article in English | MEDLINE | ID: mdl-10656398

ABSTRACT

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.


Subject(s)
Brain Neoplasms/diagnostic imaging , Brain Neoplasms/therapy , Hyperthermia, Induced/methods , Acoustics , Algorithms , Brain/anatomy & histology , Brain Neoplasms/pathology , Echoencephalography/methods , Humans , Mathematical Computing , Models, Biological , Temperature
11.
Environ Pollut ; 109(1): 147-56, 2000 Jul.
Article in English | MEDLINE | ID: mdl-15092922

ABSTRACT

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.

12.
Med Phys ; 26(9): 2007-16, 1999 Sep.
Article in English | MEDLINE | ID: mdl-10505892

ABSTRACT

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.


Subject(s)
Hyperthermia, Induced/instrumentation , Ultrasonic Therapy/instrumentation , Algorithms , Biomedical Engineering , Biophysical Phenomena , Biophysics , Humans , Models, Theoretical , Neoplasms/therapy , Temperature , Transducers
13.
Med Phys ; 26(5): 818-24, 1999 May.
Article in English | MEDLINE | ID: mdl-10360547

ABSTRACT

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.


Subject(s)
Neoplasms/radiotherapy , Ultrasonography, Interventional/instrumentation , Ultrasonography, Interventional/methods , Humans , Temperature
14.
Med Phys ; 26(5): 825-33, 1999 May.
Article in English | MEDLINE | ID: mdl-10360548

ABSTRACT

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.


Subject(s)
Fuzzy Logic , Temperature , Ultrasonography, Interventional/instrumentation , Ultrasonography, Interventional/methods , Models, Theoretical , Time Factors
15.
Med Phys ; 25(6): 1041-8, 1998 Jun.
Article in English | MEDLINE | ID: mdl-9650195

ABSTRACT

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.


Subject(s)
Breast Neoplasms/therapy , Ultrasonic Therapy/instrumentation , Biophysical Phenomena , Biophysics , Computer Simulation , Female , Humans , Models, Theoretical , Transducers , Ultrasonic Therapy/statistics & numerical data
16.
Hepatogastroenterology ; 45(19): 114-8, 1998.
Article in English | MEDLINE | ID: mdl-9496498

ABSTRACT

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.


Subject(s)
Endoscopy , Gastrointestinal Neoplasms/surgery , Adult , Aged , Endoscopy, Gastrointestinal , Female , Gastrointestinal Neoplasms/pathology , Humans , Male , Middle Aged
17.
J Formos Med Assoc ; 97(1): 21-5, 1998 Jan.
Article in English | MEDLINE | ID: mdl-9481060

ABSTRACT

The purpose of this study was to assess the predictive value of colonofiberscopy in the diagnosis of intestinal tuberculosis. The records of more than 14,000 colonofiberscopic examinations performed at the National Taiwan University Hospital from 1971 to 1995 were studied retrospectively. Colonofiberscopic diagnosis of intestinal tuberculosis required at least one of the following: circumferential ulcers, a single transverse axis ulcer with uneven base and elevated or nodular margin surrounded by nodular and hyperemic mucosa, or pseudopolyps. Sixty cases were diagnosed as intestinal tuberculosis based on these criteria, 29 of which were confirmed by histologic or bacteriologic findings or on the basis of clinical response to antituberculosis therapy. The positive predictive value of colonofiberscopy for intestinal tuberculosis was thus 43.3% (95% confidence interval 31-57%). Secondary intestinal tuberculosis with pulmonary tuberculosis accounted for 84% of cases. The most commonly involved area of the gastrointestinal tract was the ileocecal region, followed by the ascending colon and ileum. Based on our findings, colonofiberscopic examination with histopathologic and bacteriologic study of biopsy specimens is a powerful tool for the diagnosis of intestinal tuberculosis.


Subject(s)
Colonoscopy/methods , Fiber Optic Technology , Tuberculosis, Gastrointestinal/pathology , Adolescent , Adult , Aged , Female , Humans , Male , Middle Aged , Predictive Value of Tests , Retrospective Studies , Tuberculosis, Gastrointestinal/complications , Tuberculosis, Gastrointestinal/diagnosis
18.
J Formos Med Assoc ; 96(11): 879-83, 1997 Nov.
Article in English | MEDLINE | ID: mdl-9409120

ABSTRACT

This retrospective study was designed to assess the roles of stool culture for Clostridium difficile, detection of the presence of toxin A, and endoscopic examination in the diagnosis of Clostridium difficile-associated disease (CDAD). From January 1994 through September 1996, there were 213 patients with stool cultures positive for C. difficile in National Taiwan University Hospital. Of these, 126 had CDAD. There were 87 asymptomatic carriers of C. difficile in our study, 12 of whom were positive for toxin A. In addition, seven patients with pseudomembranous colitis (PMC), who were either culture-negative or not tested, were included in the study. The positive predictive values of stool cultures for CDAD and PMC were 59% and 32%, respectively. The positive predictive values of toxin A for CDAD and PMC were 41% and 43%, respectively. Seventy-eight patients (59%) improved with supportive treatment after discontinuing antibiotics. We concluded that stool culture for C. difficile and discontinuation of antibiotics should be the standard approach for patients with suspected CDAD. Endoscopic studies can eliminate some other possible causes of diarrhea such as inflammatory bowel disease, allow biopsies of suspicious lesions, and reveal the severity of CDAD. Toxin assay results need to be interpreted together with the clinical data.


Subject(s)
Bacterial Toxins , Enterocolitis, Pseudomembranous/diagnosis , Enterotoxins/analysis , Feces/microbiology , Adolescent , Adult , Aged , Aged, 80 and over , Child , Child, Preschool , Endoscopy, Gastrointestinal , Enterocolitis, Pseudomembranous/drug therapy , Female , Humans , Infant , Male , Middle Aged , Retrospective Studies
19.
J Am Coll Nutr ; 16(5): 435-8, 1997 Oct.
Article in English | MEDLINE | ID: mdl-9322192

ABSTRACT

OBJECTIVE: Nutrition is an important issue in medical training, but the nutritional knowledge, attitudes and practices of medical students in Taiwan have not been elucidated. METHODS: This investigation was a need assessment that examined knowledge, attitude and practices of medical students in selected areas of nutrition. A national sample of 528 senior medical students from nine medical colleges in Taiwan participated in this study by completing a questionnaire. RESULTS: On a 10-point scale, the average score of students on general and clinical nutritional knowledge was 5.99 +/- 1.51 and 5.15 +/- 1.77, respectively. The percentage of correct answers from questionnaires in both areas was 60% and 52%, respectively. Seventy-seven percent or more of the students reported that they either agreed or strongly agreed with four positive-attitude statements and either disagreed or strongly disagreed with two out of three negative-attitude statements. Between 30% and 61% of the students reported that they practice on nutrition-related individual behaviors. CONCLUSIONS: The knowledge, attitudes and practices of senior medical students in Taiwan suggest the need for education strategies to improve competence in the area of nutrition.


PIP: A questionnaire administered to 528 senior medical students from all 9 medical colleges in Taiwan revealed a need for curriculum modifications to improve nutrition-related knowledge, attitudes, and practices. At present, 5 of the medical schools offer elective courses on nutrition, but a nutrition curriculum is not required during medical training. The 20 items on the questionnaire concerned the nutritional functions of various nutrients, nutrition management in disease states, nutrition in disease prevention, and nutrition status assessment. On a 10-point scale, the average score was 5.99 on general nutrition knowledge and 5.15 on clinical nutritional knowledge. Correct responses were highest (77.0%) on the 2 questions concerning the nutritive content of foods and lowest (17.35%) on nutrition status assessment. Only 50% knew the definition of a balanced diet and just 30% were concerned about the caloric content of their own diet. Overall, these findings suggest that nutrition education, including an evaluation of one's own diet, should be incorporated into the training programs of Taiwanese medical students.


Subject(s)
Health Knowledge, Attitudes, Practice , Nutritional Physiological Phenomena , Students, Medical , Adult , Body Height , Body Mass Index , Body Weight , Female , Food , Humans , Male , Surveys and Questionnaires , Taiwan
20.
J Formos Med Assoc ; 96(8): 649-52, 1997 Aug.
Article in English | MEDLINE | ID: mdl-9290276

ABSTRACT

Flat adenoma has been frequently reported to have a higher potential for malignant change than other polypoid adenomas. It is an endoscopically visible sessile lesion that consists histologically of an adenomatous change of the colonic mucosa. Detection, diagnosis, and treatment of flat adenoma has not previously been reported in Taiwan. We found such lesions in two patients during colonoscopic examinations as patches of discolored and irregular mucosa. Histopathologic studies revealed adenomas with mild to moderate dysplasia. Patient 1 underwent segmental colectomy; patient 2 underwent an endoscopic strip biopsy. Focal malignant changes were noted in patient 1. Both patients received close follow-up at the outpatient clinic. No recurrence has been seen in patient 1. Patient 2 developed an enlarged sessile lesion with a histologic picture showing a tubular adenoma without malignancy but refused further surgical treatment. This paper outlines the endoscopic and pathologic characteristics of flat adenoma in two patients, and should alert physicians to the importance of early detection and treatment of this lesion.


Subject(s)
Adenoma/pathology , Colonic Neoplasms/pathology , Adenoma/therapy , Aged , Colonic Neoplasms/therapy , Female , Humans , Male
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