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Biomedical subjects

C H Chang

Publications and source records attributed to C H Chang.

At least 793 records · Page 44Linked to original sources
PubMedDate not supplied

Menopause and hormone using experiences of Chinese women in Taiwan.

The purpose of this study was to explore the menopause experiences of Chinese women in Taiwan. Six hundred and seventy-three women, aged 40 to 60 years, in the Taipei metropolitan area were chosen as the sample. These women were categorized into four groups in terms of their menopausal experiences: surgical menopause, natural menopause, perimenopause, and premenopause. The results show that the three most frequently reported discomforts that women experienced during menopause were backache/lumbago, amentia, and tiredness. The frequency of reported discomforts was low compared with frequencies reported in Western countries. The surgical group reported higher rates of symptoms than others. In addition, the hormone use rate was 13.5% for the natural menopause group, 34.4% for the surgical menopause group, 12% for the perimenopause group, and 1.9% for the premenopausal group. Higher hormone use rates were inconsistent with the general negative attitudes toward hormone use in Chinese society. Among those 59 women ever using hormones, only one third reported improvement in their symptoms. Women in Taiwan have an inadequate knowledge of menopause. Further health care education and research are needed.

Adult↗
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Symptom patterns of premenstrual dysphoric disorder as defined in the Diagnostic and Statistical Manual of Mental Disorders-IV.

Premenstrual dysphoric disorder was included in an appendix of DSM-III-R (revised third edition of the Diagnostic and Statistical Manual of Mental Disorders) and DSM-IV to facilitate systematic research. Items contained in its set of research criteria were considered tentative. Only one previous study of premenstrual symptoms specifically addressed symptoms of premenstrual dysphoric disorder, and it did not use DSM-IV criteria. In the present study, prospectively measured symptoms of 99 women were analyzed using exploratory principal components analysis with orthogonal rotation on all 24 items derived from the 11 symptoms listed in DSM-IV. Variation was found across phases of cycle and groups, with five factors predominating: (1) anger/irritability, (2) depressed mood, (3) anxiety/tension, (4) decreased energy and interest with physical symptoms, and (5) eating problems.

Adolescent↗
PubMedDate not supplied

Regional blood flow during extracorporeal membrane oxygenation in lambs.

To determine changes in blood flow to different organs during extracorporeal membrane oxygenation (ECMO), the authors performed venoarterial ECMO in four young lambs for 71-96 hr (Group 1). Macroaggregated albumin microspheres labeled with technetium 99m were injected through the perfusion cannula before termination of ECMO to determine percent of blood flow by measuring radioactivity from the microspheres lodged in specific organs. The control group (Group 2) consisted of three animals not on bypass; injections were made through a catheter placed in the left ventricle. Relative coronary blood flow from the perfusion cannula was significantly less than relative coronary blood flow in the control group, possibly because of cannula location. Renal flow from the perfusion cannula also was decreased. Contrary to observations in rabbits, cerebral perfusion did not decrease in the bypass group despite ligation of the carotid artery and the external jugular vein. There were no statistically significant differences between the two groups in the relative blood flow to other organs. The authors conclude that ECMO may significantly alter myocardial and renal perfusion, with minimal effects to other organs.

Animals↗
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Comparison of two detail screen-film systems using a rheumatoid erosion model.

Two detail screen-film systems, Lanex Fine/Ortho M and Lanex Fine/Ortho G, were evaluated using a radiographic model for rheumatoid erosions. Radiographs of hand bones with cortical defects using both screen-film systems were obtained. Seven observers analyzed 48 sites on each of 22 films for the presence of these cortical defects. Using analysis of variance techniques and receiver operating characteristic curves, no significant difference was found between the two systems for the detection of these subtle cortical defects. The authors conclude that although the Lanex Fine/Ortho M system provides better definition of laboratory test objects than Lanex Fine/Ortho G, the two systems do not differ when used for detection of cortical lesions.

Arthritis, Rheumatoid↗
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Scatter/primary ratios for x-ray spectra modified to enhance iodine contrast in screen-film mammography.

Contrast mammography to detect the uptake of iodine-containing contrast material may be enhanced by spectral modification of the x-ray beam. Luminance scatter-to-primary ratios were measured for three candidate x-ray tube anode/filter combinations (Mo/Mo, W/Ce, and Ce/Ce). Results show that scattered radiation is significant for all tubes, is lowest for the Mo/Mo system and is essentially the same for the tungsten and cerium anode systems.

Cerium↗
PubMedDate not supplied

Properties of the 18-MV photon beam from a dual energy linear accelerator.

The beam characteristics of the 18-MV photon beam of a Varian Clinac 1800 are presented. The clinically relevant parameters of central axis depth dose, tissue-phantom ratios, peak-scatter factors, and relative output factors are discussed and compared to 18-MV beam data previously reported. The nominal beam energy was found to be 18.3 +/- 0.8 MV on the central axis. The beam symmetry and uniformity meet the manufacturer's specifications. The inverse-square law is applicable within 1.4% over the clinically useful range of distances and field sizes. An empirical fit equation for the central axis depth dose is presented.

Humans↗
PubMedDate not supplied

Rapid dose calculations for stereotactic radiosurgery.

A three-dimensional dose calculation algorithm is described for stereotactic radiosurgery using multiple noncoplanar beam arcs. Precalculated dose libraries of 20-deg arc segments, or mini arcs, are stored in computer memory which permits rapid calculation of complete, high resolution, three-dimensional isodose distributions and dose volume histograms. Three-dimensional patient contours and target volumes are obtained from CT scans and angiographic x rays. Rapid dose calculations are made possible by the use of arc libraries and an improved algorithm for mapping beam doses to the dose calculation grid. This permits more flexibility in designing optimum treatment plans, as five-six complete plans can be generated in less than 1 h. Thus many possible treatment options can be tested in the 3-4-h time period typically available in stereotactic procedures between CT scanning and treatment.

Algorithms↗
PubMedDate not supplied

Rapidly progressive interstitial renal fibrosis associated with Chinese herbal medications.

BACKGROUND/AIM: Nephropathy after ingestion of Chinese herbs is known as a rapidly progressive form of interstitial renal fibrosis after a slimming regimen containing aristolochic acid that was identified first in Belgium. Intake of traditional Chinese herbal medicines is very popular in Taiwan. So we looked for similar cases in our hospital. METHODS: From 1994 to 1998, we observed 20 Taiwanese patients who underwent renal biopsy for rapidly progressive renal failure of unknown origin. The medical history of these patients gave no clue to the origin of renal impairment, except for the administration of Chinese herbs before the development of renal failure in all cases. RESULTS: Although these patients took herbal medications from various sources for different purposes, their renal biopsy specimens showed strikingly similar histological patterns: extensive paucicellular interstitial fibrosis and tubular atrophy, but the glomeruli were apparently intact. They also had similar clinical features, such as a nearly normal blood pressure, obvious anemia, insignificant edema, low-grade proteinuria, and glucosuria. The renal function declined rapidly in most cases; 15 patients underwent dialysis within 3 months of renal biopsy, and 7 patients received emergency dialysis when they first came to our hospital. On clinical and morphological grounds, the nephropathy in our patients appears similar to Chinese herb nephropathy. CONCLUSIONS: Because of the diversity of the herbal regimens used, in addition to aristolochic acid, other unidentified phytotoxins may also play a role in this particular disease entity. There is a strong relation between rapidly progressive interstitial renal fibrosis and the consumption of Chinese herbs.

Adult↗
PubMedDate not supplied

Gastric arteriolar and venular responses to nitrogenous and nonnitrogenous vasodilating agents in the rat.

We made in vivo microvascular observations to simultaneously compare the actions of various direct vasodilators on the resistance and capacitance vessels without confounding systemic hemodynamic effects. The responses of gastric submucosal arteriolar and venular diameters to the topical application of 10(-7) 10(-5), and 10(-3) M of the vasodilators nitroglycerin (NTG), sodium nitroprusside (SNP), hydralazine (HYD), and adenosine (ADN), and acetylcholine (ACh) were studied in 6 rats for each agent using in vivo microscopy. The basal diameters of arterioles, 37 +/- 2 microns (mean +/- SE), were maximally dilated to 86 +/- 2 microns by 10(-3) M ADN, NTG, SNP or ACh, while with 10(-3) M HYD dilation was just 55%. The basal diameters of venules, 36 +/- 2 microns, were maximally dilated only to 51 +/- 1 micron by 10(-3) M ADN, NTG or SNP, while those by 10(-3) M HYD and ACh were 60 and 71%, respectively. We observed that: (1) NTG and SNP were the strongest arteriolar and venular dilators, but at low dose (10(-7) M), NTG was more effective than SNP. (2) Gastric submucosal venules had considerably less dilating capacity than arterioles. (3) ADN was as effective as NTG and SNP for both arteriolar and venular dilation at 10(-3) M. It was less potent at lower concentrations. (4) ACh was as potent as ADN, NTG and SNP in dilating arterioles, but it was notably less potent in dilating venules. (5) HYD was the weakest arteriolar and venular dilator among all agents studied, and its action on venules was slightly greater than that on arterioles.

Animals↗
PubMedDate not supplied

The uneven landscape of newborn intensive care services: variation in the neonatology workforce.

CONTEXT: In the past 30 years, the number of neonatologists has increased while total births have remained nearly constant. It is not known how equitably this expanded workforce is distributed. OBJECTIVE: To determine the geographic distribution of neonatologists in the United States. DATA SOURCES: 1996 American Medical Association physician masterfiles; 1999 survey of all U.S. neonatal intensive care units; 1995 American Hospital Association hospital survey; and 1995 U.S. vital records. MEASURES: The number of neonatologists and neonatal mid-level providers per live birth within 246 market-based regions. RESULTS: The neonatology workforce varied substantially across neonatal intensive care regions. The number of neonatologists per 10,000 live births ranged from 1.2 to 25.6 with an interquintile range of 3.5 to 8.5. The weakly positive correlation between neonatologists and neonatal mid-level providers per live birth is not consistent with substitution of neonatal mid-level providers for neonatologists (Spearman rank-correlation coefficient, 0.17; P < 0.01). There was no difference in the percentage of neonatal fellows in the lowest and highest workforce quintile (14% vs. 16%) or in the percentage of neonatologists engaged predominantly in research, teaching, or administration (14% in lowest and highest quintiles). CONCLUSIONS: The regional supply of neonatologists varies dramatically and cannot be explained by the substitution of neonatal mid-level providers or by the presence of academic medical centers. Further research is warranted to understand whether neonatal intensive care resources are located in accordance with risk and whether more resources improve newborn outcomes.

Age Distribution↗
PubMedDate not supplied

Differential response in cardiomyopathy of chicks and turkeys to furazolidone toxicity.

Dietary furazolidone (500 ppm or higher) significantly slowed the growth of chicks fed either a conventional or a purified diet and of turkeys fed a conventional diet. Deaths were significantly increased in turkeys fed 500 ppm and in chicks fed 700 ppm in the purified diet. Ratio of heart to body weight was significantly increased by furazolidone in turkeys, but not in chicks. Furazolidone did not induce anemia in either species. Turkeys and chicks differed markedly in cardiac response to toxic levels of furazolidone.

Animals↗
PubMedDate not supplied

Takayasu's arteritis with aortoaortic bypass graft and renal autotransplantation: report of one case.

Takayasu's arteritis is a rare inflammatory disease of the aorta and its major branches which occurs predominantly in young women. The clinical course has been described as two stages: 1) initial phase, with inflammatory process and systemic manifestations; and later 2) pulseless phase, with multiple arterial occlusions. A 20-year-old female came to visit this hospital for the first time at 10 years of age with occlusion of the left subclavian artery and of the thoracoabdominal aorta. Aortoaortic bypass surgery was performed using a 14 mm woven graft from the ascending aorta to the descending aorta on the infrarenal portion. The postoperative course was uneventful. Exertional dyspnea and hypertension progressively developed. However, in the past year, angiograms have shown a marked stenosis on the proximal portion of the left renal artery. Autotransplantation for the left-sided kidney was performed. The patient did well, and remained free of symptoms until this time of writing, 12 months after the operation.

Aorta↗
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Tuberous sclerosis with cardiac rhabdomyoma manifested by fetal bradycardia: report of a case.

This is a case of neonatal tuberous sclerosis associated with cardiac rhabdomyoma and manifested by fetal cardiac arrhythmia-bradycardia. The prenatal echocardiography showed multiple cardiac tumors which occupied the left and right ventricles. The largest one measured 5.2 cm in diameter. It was found to be 4.5 x 4.1 x 3.5 cm in size at autopsy. A postnatal cranial echogram showed multiple subependymal nodules. The patient expired after 7 hours of life. The autopsy findings confirmed the diagnosis. The mother of the patient had adenoma seb'aceum on the face and an ungual fibroma on the left little finger. Cranial computerized tomography revealed a small calcified tubercle.

Adult↗
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Postoperative echocardiographic study of patients with symptomatic chronic aortic regurgitation.

Aortic valve replacement was performed in 31 patients with symptomatic chronic aortic regurgitation. The patients ranged in age from 13 to 66 (mean = 39) years and included 29 men and 2 women. They were followed up for a mean of 47 months. Perioperatively, 2 patients (6.5%) died, and 2 (6.5%) received a permanent pacemaker for complete heart block. Thirty patients received an M-mode echocardiographic examination both before, and 6 to 11 days after, the operation. In this early postoperative period, the end-diastolic dimension (EDD) and left ventricular end-diastolic radius/posterior wall thickness ratio (R/Th) decreased in all patients. This decrease in EDD could be predicted by preoperative ejection fraction (EF), but not by end-systolic dimension (ESD) or R/Th ratio. The ESD regressed only in patients with preoperative EF greater than 50%, or ESD less than 55mm, or R/Th less than 3.8. During the long-term follow-up, one each had mild tissue valve degeneration, stroke, infective endocarditis, and severe myocardial failure, but none died. Eighteen patients had repeated M-mode echocardiographic studies. There was no further regression of EDD and R/Th, while ESD showed significant decrease. The EF and fractional shortening (FS) did not change. Clinically, the patients who survived the operation improved or remained unchanged postoperatively in a functional status. However, those who had preoperative EF greater than 50% or ESD less than 55mm had a better postoperative functional class (1.2 +/- 0.4 vs 1.9 +/- 1.0, p less than 0.05, 1.2 +/- 0.4 vs 2.0 +/- 1.1, p less than 0.05, respectively). Thus, patients with symptomatic chronic aortic regurgitation can often benefit from valve replacement.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
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Neuromyelitis optica (Devic's disease) report of one case.

Neuromyelitis optica also named Devic's disease is an acute combined optic neuritis and transverse myelitis. It is thought to be a variant of multiple sclerosis, but its clinical presentation probably has only one attack without further recurrence and exacerbation. We present a 12-year-old girl who suffered from sudden onset of lower extremeties weakness, sensory loss and blurred vision after a prodromal URI symptom. CSF examination showed mild pleocytosis, elevated immunoglobulins, mild elevation of protein concentration. No oligoclonal band was detected. Serum virology showed high titer of anti-EB virus antibody. Visual evoke potential showed prolong of latency and decreased amplitude of both eyes. After prednisolone treatment, her visual accuity began to improve on the 7th hospital day and motor function improved on the 11th hospital day. Two years later, she has normal visual accuity, normal motor function and shows no evidence of disease recurrence.

Antibodies, Viral↗
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[Congenital coronary arteriovenous fistula: analysis of five cases].

The records of 5 patients with congenital coronary arteriovenous fistula, diagnosed by echocardiogram, cardiac catheterization, angiocardiography and confirmed by cardiac surgery between 1982 and 1988, were studied. Their ages ranged from 3 months to 13 years. Among them, 3 were asymptomatic; one developed congestive heart failure shortly after birth, and was treated with digoxin and furosemide. Another patient had exertional dyspnea and fatigue. A grade 3-4/6 continuous murmur was heard over the right or left lower sternal border in four patients; only a pansystolic murmur was heard over the left lower sternal border in the remaining one patient. All the five patients had right coronary arteriovenous fistula terminating into the right ventricle. All received cardiac surgery. Direct epicardial ligation of the fistula was performed in one patient. The rest four cases required cardiopulmonary bypass and suture closure through the right ventricle by direct suture of the orifice in one patient, and Dacron patch closure in other three patients. No postoperative complications occurred in all patients. In conclusion, since the operation was quite safe, if patient had significant shunts and/or clinical symptoms, surgical correction should be considered.

Adolescent↗