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Biomedical subjects

M T Chen

Publications and source records attributed to M T Chen.

At least 19 recordsLinked to original sources
PubMed1998

Sp1 binds to the rat luteinizing hormone beta (LHbeta) gene promoter and mediates gonadotropin-releasing hormone-stimulated expression of the LHbeta subunit gene.

The hypothalamic hormone gonadotropin-releasing hormone (GnRH) plays a critical role in reproductive function by regulating the biosynthesis and secretion of the pituitary gonadotropins. Although it is known that GnRH induces luteinizing hormone beta (LHbeta) gene transcription, the mechanisms by which this occurs remain to be elucidated. We have shown previously that GH3 cells transfected with the rat GnRH receptor cDNA (GGH3-1' cells) support the expression of a cotransfected fusion gene composed of 797 base pairs of rat LHbeta gene 5'-flanking sequence and the first 5 base pairs of the 5'-untranslated region fused to a luciferase reporter (-797/+5LHbetaLUC) and respond to a GnRH agonist with a 10-fold stimulation of activity. Furthermore, we have shown that DNA sequences at -490/-352 confer GnRH responsiveness to the rat LHbeta gene. We have now identified two putative binding sites for Sp1, a three-zinc-finger transcription factor, within this region. Using electrophoretic mobility shift assay, DNase I footprinting, and methylation interference assays, we demonstrate that Sp1 can bind to these sites and that Sp1 is responsible for DNA-protein complexes formed using GGH3-1' and alphaT3-1 nuclear extracts. Mutations of the Sp1 binding sites, which block binding of Sp1, blunt the stimulation of the LHbeta gene promoter by GnRH. These data define GnRH-responsive elements in the LHbeta 5'-flanking sequence and suggest that Sp1 plays an important role in conferring GnRH responsiveness to the LHbeta subunit gene.

Animals↗
PubMed1998

Changes in the activities of mitochondrial enzymes in the progress of tumorigenesis of bladder cancer.

To investigate changes in the activities of mitochondrial enzymes in the progress of tumorigenesis of bladder cancer, N-butyl-N-(4-hydroxybutyl) nitrosamine (BBN) carcinogen was administered orally to male Sprague-Dawley rats for eight weeks. The urinary bladders were harvested periodically for the evaluation of tumorigenesis. The activities of NADH cytochrome c reductase (NCCR), succinate cytochrone c reductase (SCCR) and cytochrome c oxidase (CCO) were measured. The NCCR and SCCR activities elevated significantly by the exposure of BBN and decreased rapidly when BBN was withdrawn. However, the CCO activity increased and reached plateau at 18 weeks in spite of the discontinuance of BBN. The results indicated that the NCCR, SCCR and CCO activities were significantly elevated in the tumorigenesis. However, the CCO enzyme may be more related to the progress of tumorigenesis of bladder cancer.

Animals↗
PubMed1998

[Changing trends of ureteral injuries].

Ureteral injury is a potential complication of any abdominal or pelvic surgery. Gynecological surgery has traditionally accounted for most injuries. In the last decade, there have been major advances in endoscopic surgery including ureteroscopy and laparoscopy, both of which may cause ureteral injury. Increased use of these procedures change the nature of ureteral injuries. From 1988 to 1997, 22 patients with 24 ureteral injuries were identified. The causes, diagnostic methods and treatments were reviewed. Ureteral injury was defined as any laceration, transection or ligation of the ureter that required an unexpected procedure for repair, stent or drainage. In 24 ureteral injuries, there were 20 unilateral cases and 2 bilateral cases eight men (33%) were 15 to 43 years old (mean age 30), and 14 women including 2 case of bilateral lesion (67%) were 30 to 75 years old (mean age of 46). The injuries were on the right side in 11 cases (46%), left side 13 cases (54%), and in the upper, and lower third of the ureter in 7 (29%) and 17 cases (71%), respectively. Bilateral injuries were all in the lower ureter and another 2 cases of lower ureteral injuries were combined with bladder injuries. In the cases of ureteral injuries, iatrogenic injuries accounted for 19 cases (79%). Of these, urological surgery, laparoscopic surgery, ureteroscopic procedures and gynecological surgery accounted for 1 (4%), 2(8%), 5(21%) and 11 cases (46%) respectively. Between 1988 and 1992, there were 7 cases, and after 1993, there were 17 cases of ureteral injuries. The injuries caused by trauma and gynecological surgery remained stable in the 2 period. The recent increases were caused by endoscopic procedures including ureteroscopy and laparoscopy. Of the 24 cases, 13 cases (54%) were managed by ureteroneocystostomy, 5 cases (21%) by nephrectomy, 4 cases (17%) by ureteroureterotomy, 1 case by PCN and 1 case by double-J catheter stenting only. The early recognition and repair at injury allow for better results with fewer complications. Delayed finding or commitant infection may lead to failure of reconstructive procedure and lead to nephrectomy.

Adult↗
PubMed1997

Paraneoplastic elevation of serum alkaline phosphatase in renal cell carcinoma: incidence and implication on prognosis.

PURPOSE: We investigated the incidence and prognostic significance of paraneoplastic elevation of serum alkaline phosphatase in patients with renal cell carcinoma. MATERIALS AND METHODS: Clinical data of 365 pathologically proved renal cell carcinoma cases were reviewed. Serum alkaline phosphatase level greater than 100 units per 1., but without obvious conditions that may cause phosphatase elevation, including metastasis to or disease of liver or bone and pregnancy, was regarded as paraneoplastic serum alkaline phosphatase elevation. Survival was evaluated using the Kaplan-Meier method. RESULTS: Of 365 patients 77 (21.1%) had paraneoplastic serum alkaline phosphatase elevation. The respective incidence from stage I to IV cases was 9.9% (16 of 161), 31.9% (15 of 47), 34.3% (23 of 67) and 25.6% (23 of 90). Patients with stage I disease had the lowest incidence but there were no statistically significant differences among stages II, III and IV disease. Of 77 patients with elevated serum alkaline phosphatase 48 had additional paraneoplastic manifestations. The disease specific 5-year survival rate in patients with normal serum alkaline phosphatase was significantly better than in patients with isolated phosphatase elevation, which in turn was better than in patients with multiple paraneoplastic syndromes (70.7 versus 50.5 versus 30.8%). Patients with persistent or recurrent elevation of serum alkaline phosphatase after radical nephrectomy had metastatic lesion or local recurrence. In some patients serum alkaline phosphatase returned to normal after nephrectomy but metastasis developed later without recurrent phosphatase elevation. CONCLUSIONS: Paraneoplastic serum alkaline phosphatase elevation in renal cell carcinoma patients implies an unfavorable prognosis, and additional paraneoplastic syndromes further worsen the prognosis. Recurrent or persistent serum alkaline phosphatase elevation after radical nephrectomy suggests distant metastasis or residual tumor. However, the return of serum alkaline phosphatase to normal does not guarantee cure of the disease. Identification of paraneoplastic serum alkaline phosphatase elevation is valuable in the prediction of outcome and postoperative followup of renal cell carcinoma patients.

Alkaline Phosphatase↗
PubMed1997

Acceleration of post-mortem changes in Tsaiya duck (Anas platyrhynchos) breast muscle by lactic acid marination.

1. The effect of lactic acid marination at 5 degrees C on post mortem changes in breast muscle pectoralis major of spent layer Tsaiya duck was studied. 2. Myofibrils were prepared from 0.1 M and 0.2 M lactic acid marinated muscle and control (non-marinated samples) sampled at 0, 1, 3, 7 and 14 d post mortem. 3. Changes in myofibril fragmentation index (MFI), myofibrillar proteins and Z-line structure were examined. 4. Marination of duck breast muscle in lactic acid at 5 degrees C enhanced fragmentation of myofibrils and degradation of myofibrillar proteins and Z-line structure as compared to control samples. 5. In summary, lactic acid marination at 5 degrees C can accelerate the post mortem degradation of myofibrils in Tsaiya duck breast muscle.

Actinin↗
PubMed1997

Relationships between beta-cell function and diabetic duration and albuminuria in type 2 diabetes mellitus.

To clarify whether beta-cell function deteriorates with increasing albuminuria and duration of diabetes, we investigated the insulin and c-peptide response to oral glucose tolerance test in 47 healthy subjects and 75 normoalbuminuric (group 1), 30 microalbuminuric (group 2), and 35 macroalbuminuric (group 3) Type 2 diabetes mellitus patients. The total area under the insulin curve (AUCI) values of groups 1, 2, and 3 were 245 +/- 16, 193 +/- 17, and 88 +/- 8 pmol/L.h, respectively, significantly lower than that (624 +/- 34 pmol/L.h) of the healthy group. The mean total area under the c-peptide curve (AUCC-P) values of groups 1, 2, and 3, respectively, were 2.50 +/- 0.11, 2.05 +/- 0.15, and 1.73 +/- 0.07 nmol/L.h, respectively, significantly lower than that (5.47 +/- 0.19 nmol/L.h) of the healthy controls. The mean AUCI and AUCC-P values of group 3 were significantly reduced compared to those of group 1. The mean AUCI and AUCC-P values of patients with 0-5, 5-10, 10-15, and > 15 years' duration were significantly decreased compared to those of healthy subjects. The mean AUCI and AUCC-P values of patients with > 15 years' duration were significantly lower than those of patients with 0-5 years' duration. The mean hemoglobin Alc values of the three diabetic groups were not significantly different. These data suggest that beta-cell function deterioration was associated with increasing albuminuria and diabetic duration in Type 2 diabetic patients.

Albuminuria↗
PubMed1997

Percutaneous drainage in the treatment of emphysematous pyelonephritis: 10-year experience.

PURPOSE: We investigated the effect of percutaneous drainage for the treatment of emphysematous pyelonephritis. MATERIALS AND METHODS: A retrospective analysis was done of 25 patients with emphysematous pyelonephritis who were treated initially with computerized tomography (CT) guided percutaneous drainage during a 10-year period. The patients were concomitantly treated with antibiotics, fluids, and correcting blood glucose and/or ureteral obstruction. We also compared our results of percutaneous drainage to CT findings. RESULTS: CT identified 12 patients with emphysematous pyelonephritis who had gas with little fluid and 13 who had gas with renal or perirenal fluid collections. In 20 of 25 patients (80%) antibiotic therapy combined with percutaneous drainage constituted the only treatment required. Three patients (12%) whose clinical status improved after percutaneous drainage subsequently underwent elective nephrectomy without further complications. Two patients (8%) died of multiple organ failure. There was no correlation between the gas patterns of emphysematous pyelonephritis and initial success with the antibiotics and percutaneous drainage. There were no recurrences and no complications during a followup of 1 to 10 years (mean 5). Mean duration of treatment was 5.54 weeks (range 1 to 12.6). CONCLUSIONS: CT is an efficient imaging method for diagnosis, guiding the drainage procedures and monitoring response to percutaneous drainage of emphysematous pyelonephritis. Antibiotic therapy combined with CT guided percutaneous drainage of emphysematous pyelonephritis is an acceptable alternative to antibiotic therapy with surgical intervention.

Adult↗
PubMed1997

Successful early separation of a premature xipho-omphalopagus conjoined twins: a case report.

Premature xipho-omphalopagus conjoined twins were successfully separated at 7 days of age. The total body weight of the twins before separation was 3502 g. One twin had persistent patent ductus arteriosus and signs of cardiac failure at 4 days of age. This was managed with indomethacin. Thirty-six hours later the second twin became anuric, necessitating early emergency separation. The twins were joined from the lower sternum to the infraumbilical area. The liver was fused, but there was no major vascular connection. There were no other major anomalies. The babies stood the procedure well and were healthy at follow-up 8 months after separation.

Abnormalities, Multiple↗
PubMed1997

Osteomyelitis and tenosynovitis due to Mycobacterium marinum in a fish dealer.

Osteomyelitis caused by nontuberculous mycobacteria is rarely reported. We describe a case of tenosynovitis and osteomyelitis of the right middle finger and metacarpal bone caused by Mycobacterium marinum in a fish dealer. This 52-year-old woman suffered progressive pain, numbness, tenderness, and erythematous swelling of the right middle finger over a 2-month period. A radiograph of the right hand disclosed osteolytic lesions at the third metacarpal bone and the third proximal phalanx. She was treated successfully with repeated surgical debridement and antimicrobial agents, including clarithromycin, ethambutol, rifampin, and doxycycline for 1 month, followed by ethambutol and clarithromycin. Pathologic examination of the debrided tissue disclosed epithelioid granuloma, caseous necrosis, and numerous acid-fast bacilli, which were later identified as M. marinum using conventional biochemical tests and by the characteristic gas-liquid chromatogram of esterified cellular fatty acid. The wound healed completely after 7 months of treatment. The patient is still under treatment, and clarithromycin and ethambutol will be given for a total of 18 months.

Animals↗
PubMed1997

The correlation between ultrasound-detected renal parenchymal thickness and isotope-detected individual renal function.

Ultrasound has been used as a convenient examination method to obtain an estimate of the kidney size and parenchymal thickness. The aim of this study was to determine the relationship between the renal parenchymal thickness and individual renal function. Renal ultrasonography to determine parenchymal thickness and 99mTc-DTPA renal scan to detect individual renal function were carried out on 30 patients. The statistic analysis showed poor correlation between these two factors. The correlation coefficients is 0.1 only. However, the correlation coefficients of the difference of bilateral renal parenchymal thickness and the difference of bilateral renal function in the same patient is much higher (r = 0.67). So, it is unreliable to predict the random single renal function based on parenchymal thickness only. However, in the same patient, it is sometimes worthwhile to differentiate bilateral renal function based on the difference of renal parenchymal thickness between the two kidneys.

Adult↗
PubMed1997

Balanced fluid exchange by volume homeostatic fluid-fluid exchanger--a new solution to postvitrectomy vitreous hemorrhage.

We introduce a new device and a new technique that facilitate the clearance of postvitrectomy vitreous hemorrhage. We have developed a volume homeostatic fluid-fluid exchanger--Chen's Infusion/Aspiration (Chen's I/A) device. Due to reciprocal synchronized hydraulic action, Chen's I/A provides simultaneous infusion and aspiration of fluid of equal amounts. Therefore, it can be used to perform vitreous cavity lavage through smaller caliber needles and at the same time maintain a constant intraocular pressure. This improved vitreous cavity lavage technique is named Balanced Fluid Exchange. Performing Balanced Fluid Exchange with Chen's I/A can reduce trauma to the eyeball and decrease complications resulting from unstable intraocular pressure. Thus, it increases both the intra-operative and post-operative clearance rates of postvitrectomy vitreous hemorrhage, and is a promising method for the management of postvitrectomy vitreous hemorrhage.

Hemostatic Techniques↗
PubMed1996

Incomplete pregnancies and risk of ovarian cancer (Washington, United States).

Because of the reduced risk of ovarian cancer related to prior full-term pregnancies, we sought to determine whether there was any association with a history of one or more incomplete pregnancies. White female residents of three counties in Washington State (United States) diagnosed with ovarian cancer during 1986-88 (n = 322), and a random sample of control women selected from these same counties (n = 426), were interviewed regarding their pregnancy and childbearing histories. Among women who had given birth to at least one child, an additional incomplete pregnancy was not associated with the risk of ovarian cancer (relative risk [RR] = 1.1, 95 percent confidence interval [CI] = 0.8-1.6, adjusting for age, oral contraceptive use, and number of births). For those who had never given birth, a somewhat smaller proportion of cases had a history of incomplete pregnancy than controls (RR = 0.8, CI = 0.4-1.7). In an analysis restricted to ever-pregnant women, a prior induced or spontaneous abortion was not found to be associated with the incidence of ovarian tumors (RR = 1.0, CI = 0.6-1.7, and RR = 1.3, CI = 0.8-1.9, respectively). Other studies of the possible relation between incomplete pregnancies and ovarian cancer generally have observed either a weak negative association or no association at all. It is possible that if incomplete pregnancies do affect the risk of ovarian cancer, their impact might be too small to be identified reliably through epidemiologic studies.

Abortion, Induced↗
PubMed1996

Treatment of high-flow vascular malformations in the head and neck with arterial ligation followed by sclerotherapy.

The traditional treatment of high-flow vascular malformations consists of selective embolization, surgical removal, or a combination of both. Recurrence of the lesion and bleeding control are still the main problems, and the result of treatment is sometimes disappointing. We suggest treatment of these lesions with surgical ligation of the distal major feeding arteries followed by intravascular injection of a sclerosing agent (3% tetradecyl sulfate), and surgical excision and reconstruction when indicated. We have found this to be an effective treatment regimen. We present 14 cases of high-flow vascular malformations of the head and neck area treated with this approach, of which 4 cases developed skin necrosis. Three of these 4 cases of skin necrosis were later treated with skin grafting and, in 1 case, an upper arm skin tube flap was used for nasal tip reconstruction. Three cases underwent delayed reconstruction using tissue expanders. From a symptomatic and aesthetic point of view, preliminary satisfactory results were obtained. We feel that this approach is a good option for treating difficult, high-flow vascular malformations.

Adolescent↗
PubMed1996

Dynamic infusion cavernosometry and cavernosography (DICC) in the evaluation of vasculogenic impotence.

BACKGROUND: This study was conducted to find more accurate physiological assessment of the penile vascular status in impotent patients. METHODS: Twenty-two males, aged 25-76 years (mean 54.0 years) with possible underlying vascular causes of impotence, had dynamic infusion cavernosometry and cavernosography (DICC) examination to ascertain the arterial and/or venous insufficiency in the penis. Prostaglandin E1 20 micrograms was injected intracavernously in this 4-phase study. RESULTS: No side effect or complication was noted during or after the examination in all 22 patients. During the phase 1 test, the mean resting intracavernous pressure (ICP) was 6.8 +/- 3.6 mmHg and the mean plateau ICP after PGE1 injection was 47.2 +/- 23.9 mmHg. The mean ratio of plateau ICP to mean arterial pressure was 50.2 +/- 23.4%. In the phase 2, the mean ICP determined 30 seconds after cessation of saline infusion without and with perineal compression was 65.3 +/- 26.8 mmHg and 129.1 +/- 26.2 mmHg, respectively. The mean ICP decay from 150 mmHg was 84.7 +/- 26.8 mmHg. The mean systolic pressure of each cavernous artery, 87.6 +/- 18.9 mmHg and 93.6 +/- 17.6 mmHg in left and right side, respectively, was found during phase 3 evaluation. The mean ratio of systolic pressure of each cavernous artery to brachial artery (cavernous-brachial index, CBI) was 70.1 +/- 12.7% and 75.1 +/- 11.5% in left and right side, respectively. Six patients with CBI greater than 75% had normal Doppler duplex sonography (diameter of cavernous artery greater than 0.9 mm and peak flow velocity greater than 25 cm/sec). Cavernosography in phase 4 evaluation showed venous leakage in 20 of 22 patients (90.9%) with ICP decay greater than 60 mmHg. Two patients with ICP decay less than 45 mmHg were found to have no venous leakage. CONCLUSIONS: The cavernous-brachial index is usually less than 75% in penile arterial insufficiency. The patients with ICP decay from 150 mmHg greater than 60 mmHg would have penile venous leakage demonstrated in the cavernosography. The results of cavernosometry are highly correlated with cavernosography. Our results suggest that DICC may provide a good examination for more physiological assessment and accurate diagnosis of vasculogenic impotence.

Adult↗
PubMed1996

Pheochromocytoma of the urinary bladder: a case report.

A 61-year-old female was admitted who had had symptoms of hematuria and a tumor mass in the urinary bladder for six months. Hypertension and headache after micturition had been noted for one year. Plasma norepinephrine before and after voiding were elevated. Increased I-131 metaiodobenzylguanidine (I-131 MIBG) uptake in the urinary bladder was also found. The plasma norepinephrine level and blood pressure returned to normal after partial cystectomy. Diagnosis of pheochromocytoma was confirmed by histology.

3-Iodobenzylguanidine↗
PubMed1996

Malignant chondroid syringoma.

A case of malignant chondroid syringoma on a foot with multiple bone metastases is presented. An 18-year-old male patient first noticed a protruding mass on the plantar surface of his right foot at 9 years of age. A sweat gland tumor of a benign nature was diagnosed and excised at that time. The tumor recurred three times during the 10 years after surgery and was finally diagnosed as malignant chondroid syringoma. Multiple bone metastases involving the calcaneus, talus and fibula of the lesion side were found after extensive radiologic survey. The patient underwent below-knee amputation with total removal of the fibula. However, pelvic bone metastasis developed 1 year after the amputation. He died of this disease due to brain and diffuse bony metastasis 36 months after the amputation. This is a rare case of malignant chondroid syringoma with a long history but ominous outcome. We recommend that sweat gland tumors be carefully examined and treated more radically when there is a suspicion of malignancy.

Adenoma, Pleomorphic↗
PubMed1995

Blood flow of the urinary bladder: effects of outlet obstruction and correlation with bioenergetic metabolism.

This study investigated the effects of outlet obstruction on blood flow and high energy phosphates content in the rabbit urinary bladder. Mild bladder outlet obstruction was induced by placing a silicon ring (diameter 7 mm) around the bladder neck of each male New Zealand White rabbit (n = 7). Before and immediately after inducing obstruction, and 2 weeks later, the bladders were emptied and regional blood flow measured using laser Doppler flowmetry (LASERFLO BPM2, Vasamedics Inc., St. Paul, Minnesota). Six different areas of each bladder were measured, and the average blood flow calculated for each rabbit. Then, the animals were sacrificed, the bladder excised, and the tissue content of high energy phosphates determined by high performance liquid chromatography (HPLC). Six normal male New Zealand White rabbits served as controls. The results can be summarized as follows: (1) Before surgery, bladder blood flow was similar in all animals (16.3 ml/min/100 g); positioning the silicon ring around the bladder neck did not affect blood perfusion, two weeks after the induction of outlet obstruction, bladder blood flow was significantly decreased (4.9 ml/min/100 g). (2) There was no significant difference between control and obstructed bladders in NAD, AMP, or ADP content. However, the obstructed bladders contained significantly less phosphocreatine (12.0 vs 21.9 nmol/mg protein) and ATP (4.0 vs. 6.1 nmol/mg protein) than control bladders. In summary, this study showed that urinary bladder blood flow was reduced by outlet obstruction, and the reduction in blood flow was associated with decreased tissue high energy phosphates content.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenine Nucleotides↗