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Biomedical subjects

M T Chen

Publications and source records attributed to M T Chen.

At least 55 records · Page 3Linked to original sources
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↗
PubMed1995

Effect of orchiectomy on the alpha adrenergic contractile response of dog prostate.

PURPOSE: To investigate the effect of androgen deprivation on the alpha-adrenergic contractile response of the dog prostate using both in vitro and in vivo methods. MATERIALS AND METHODS: In vitro muscle bath study: One month after surgery, responses to KCl (120 mM.) and norepinephrine (10(-8) to 10(-3)M.) of prostatic tissue strips (of the same size) from castrated (n = 6) and sham-operated (n = 6) adult mongrel dogs were determined. In vivo study: Before and 1 month after surgery, the intraprostatic urethral pressure response to intravenous norepinephrine administration of 6 castrated and 5 sham-operated adult dogs was examined. RESULTS: (1) Before castration the serum level of testosterone was 1.24 +/- 0.2 ng./ml.; 1 month after castration, it had dropped to an undetectable level. (2) Histological examination of the prostates from castrated animals revealed profound atrophy of glandular tissue with a relatively increased stromal tissue component in each section. (3) In vitro study: The contractile responses to KCl and norepinephrine of individual prostate strips (same size) from castrated animals were significantly higher than control. However, if the response to norepinephrine was normalized to the response to KCl, there was no significant difference in response to norepinephrine between the 2 groups. In addition, the ED50 of the norepinephrine-stimulated contractile response was not changed by castration. (4) In vivo study: There was no significant change in intraprostatic urethral pressure response to intravenous norepinephrine administration after orchiectomy. CONCLUSIONS: The results of this study show that the sensitivity of the alpha-adrenergic contractile response of the dog prostate is not affected by androgen deprivation, nor is alpha-adrenergic contractile activity of the dog prostate regulated by androgen.

Adrenergic alpha-Agonists↗
PubMed1995

Adrenal cortical carcinoma with tumor thrombus invasion of inferior vena cava.

A case of adrenal cortical carcinoma with inferior vena cava (IVC) involvement is presented. Ultrasonography, computed tomography, and venacavography all presumptively showed a large mass over the upper pole of the left kidney with tumor thrombus in the IVC. However, aortography demonstrated that this mass was receiving its blood supply from the left inferior phrenic artery, aorta, and left renal artery. Radical surgery, including resection of the tumor and its adjacent organs (kidney, distal pancreas, spleen) and the tumor thrombus in the IVC, with the aid of cardiopulmonary bypass, was performed. We emphasize that adrenal cortical carcinoma can have tumor thrombi invading the IVC, and in such cases we suggest radical surgical removal of the tumor and the thrombus.

Adrenal Cortex Neoplasms↗
PubMed1995

Defective mitochondrial oxidative phosphorylation in varicocele-bearing testicles.

OBJECTIVES: Our previous study revealed a decreased blood flow in varicocele-bearing testicles. For further understanding of the possible mechanism of varicocele-induced infertility, we investigated the changes in energy metabolism in varicocele-bearing testicles. METHODS: Partial ligation of the left renal vein was performed in 40 Wistar rats to induce dilation of the internal spermatic vein, and sham operations were performed in 20 other age-matched Wistar rats serving as controls. Orchiectomy was done at 1, 2, 4, and 6 months after induction of varicocele (or sham operation) in both groups. The histologic changes in the testicles were evaluated under the light microscope. The concentration of adenine nucleotides was determined by high-performance liquid chromatography, and various enzyme activities of mitochondria were determined by a spectrophotometer. RESULTS: Histologic studies of varicocele-bearing testicles showed a lower Johnsen score (8.5 +/- 0.7 versus 9.3 +/- 0.5) and a decreased mean testicular tubular diameter (280.0 +/- 3.2 versus 295.0 +/- 1.4 microns) compared with the testicles in the sham-operated group. The energy charge decreased from 0.71 +/- 0.04, 0.70 +/- 0.03, 0.69 +/- 0.06, and 0.64 +/- 0.03 to 0.62 +/- 0.08, 0.59 +/- 0.05, 0.58 +/- 0.05, and 0.56 +/- 0.02 at 1, 2, 4, and 6 months, respectively. The reduced nicotinamide-adenine dinucleotide-cytochrome c reductase activities were decreased from 136.6 +/- 4.9, 127.3 +/- 10.7, 121.6 +/- 7.8, and 118.9 +/- 8.5 to 96.3 +/- 13.9, 95.6 +/- 27.8, 88.3 +/- 13.8, and 80.4 +/- 8.7 nmol/min/mg of protein, respectively; the succinate-cytochrome c reductase activities were decreased from 50.4 +/- 2.7, 49.0 +/- 4.7, 49.6 +/- 7.1, and 42.6 +/- 1.6 to 40.3 +/- 7.3, 41.0 +/- 11.5, 40.2 +/- 5.7, and 32.0 +/- 1.3 nmol/min/mg of protein, respectively; and the cytochrome c oxidase activities were decreased from 361.2 +/- 23.4, 350.3 +/- 25.5, 223.5 +/- 12.9, and 194.1 +/- 18.3 to 253.7 +/- 32.9, 256.4 +/- 38.8, 178.2 +/- 15.7, and 147.1 +/- 17.2 nmol/min/mg of protein at 1, 2, 4, and 6 months, respectively. CONCLUSIONS: We thus suggest that defective energy metabolism plays an important role in the impairment of spermatogenesis of varicocele-bearing testicles.

Animals↗
PubMed1995

Laparoscopic nephrolysis for chyluria: case report of long-term success.

Laparoscopic nephrolysis was performed in an 81-year-old man with recurrent chyluria. A total of five trocars were used for approaching the lymphatic ducts over the right ureter and renal hilum. The lymphatic ducts identified were easily ligated under laparoscopic magnification. The recovery of this patient was quick and uneventful. The follow-up urinalysis for chyle was negative, and his serum albumin concentration increased from 3.0 g/dL to 4.2 g/dL at 2 years postoperatively. This case report attests to the long-term efficacy of a laparoscopic approach to ligation of lymphatic fistulas for the treatment of recalcitrant chyluria.

Aged↗
PubMed1995

[Epidermoid cyst of testis: benign testicular tumor].

Epidermoid cyst of the testis is very rare and accounts for approximately 1% of all testicular tumors. In the clinical examination, the testis has a palpable mass. Pathological findings usually reveal a squamous cell lined cyst, containing keratin, and the absence of appendages and teratoma element. If scrotum ultrasonography reveals a target sign suggestive of epidermoid cyst, the testis should be explored through an inguinal incision. Clamp the spermatic cord gently, and perform tumor enucleation. The frozen section is available at the time to check for any malignant cells. If no malignant cells exist, it is important to perform testis-preserving surgery, especially for young adults and children. We report two cases of epidermoid cyst. Serum beta-HCG and alpha-fetoprotein were within normal limits. We review our experience with scrotum ultrasonography and testis-preserving surgery in 2 men with epidermoid cyst to indicate when the clinical and intraoperative characteristics justify testis-preserving management.

Adolescent↗
PubMed1995

Spontaneous tendon rupture in rheumatoid hand-successful reconstruction with tendon transfer: a case report.

Rheumatoid arthritis is not as common a problem in Taiwan as it is in western countries. Compared with traumatic tendon rupture, tendon rupture in rheumatoid arthritis has its complex and peculiar pathophysiological mechanism which includes chemical erosion by hypertrophic synovium and mechanical attrition by deformed joints and bony spurs. In management, all these pathological foci must be eradicated to prevent recurrent failure. Tendon transfer is a simple and effective method for reconstructing lost tendon function.

Arthritis, Rheumatoid↗
PubMed1995

Recent experience of penile fracture (1989-1993).

Penile fracture is an uncommon injury in the genitourinary organ which occurs following a blunt injury on the rigid penis. Penile fracture with urethral injury is even rarer. A total of 11 new patients with penile fracture were treated at our institution from 1989 to 1993. All of these injuries occurred during sexual intercourse and received immediate surgical repair to preserve the sexual function. Only one patient with complete transection of the urethra received end-to-end anastomosis of the urethra. Unfortunately, he suffered from urethral-cutaneous fistula ten days later. Suprapubic urinary diversion was performed in 3 patients with partial urethral tearing, and they enjoyed satisfactory outcomes during the limited follow-up. Immediate surgical repair of tunica albuginea is recommended for preserving penile function. If associated with partial urethral tear, suprapubic urinary diversion is sufficient to treat urethral lesions.

Adult↗
PubMed1994

Separation of ischiopagus tripus conjoined twins.

The authors report on their second experience of a successful separation of ischiopagus tripus conjoined twins. Particular emphasis is placed on the painful decision of sacrificing the only available leg to cover the infected wound after an unexpected complication in twin A. The twins' preoperative evaluation, separation surgery, and subsequent 16-month course are described.

Humans↗
PubMed1994

The time for serum testosterone to reach castrate level after bilateral orchiectomy or oral estrogen in the management of metastatic prostatic cancer.

OBJECTIVE: To understand the time for serum testosterone to reach castrate level after bilateral orchiectomy or oral estrogen in the management of metastatic prostatic cancer. METHODS: A total of 20 consecutive patients with adenocarcinoma of the prostate with bony metastasis were enrolled in this study. Their mean age was 72.8 years old (range, 57 to 82 years). Pretreatment serum testosterone levels were obtained in all men. Thirteen men were treated with bilateral orchiectomy. Immediately after removal of testes, serial blood samplings for serum testosterone levels were drawn every fifteen minutes for the first two hours, then hourly for another sixteen hours. Seven men were treated with oral estrogen diethylstilbestrol (DES), 3 mg per day. Serum testosterone levels were checked on a weekly basis for two months, and then biweekly for another two months. RESULTS: Castration time of bilateral orchiectomy ranges from three to twelve hours (mean, 8.6 hours). The biological half-life of serum testosterone was from thirty to sixty minutes (mean, 45 minutes). Castration time of oral estrogen (DES) was from twenty-one to sixty days (mean, 38.3 days). CONCLUSIONS: Bilateral orchiectomy and oral estrogen were both effective ways of castration for patients with bony metastatic prostatic cancer. Bilateral orchiectomy provides a more rapid castration and is one hundred seven times faster than oral estrogen in reaching castrate level.

Adenocarcinoma↗
PubMed1994

The long-term stone recurrence rate and renal function change in unilateral nephrectomy urolithiasis patients.

We evaluated the stone recurrence rate and long-term renal function in 50 patients with a solitary kidney 60 to 84 months (mean 70.6) after unilateral nephrectomy for urinary tract stone disease. Followup evaluation included a detailed history, physical examination, blood and urine biochemistry studies, urinalysis, urine culture, excretory urography, ultrasonography of the kidney and 131iodine-ortho-iodohippurate renography. The overall stone recurrence rate in unilateral nephrectomy urolithiasis patients was 30% (15 of 50). The mean interval until stone recurrence was 31.1 months (range 6 to 74) and the mean episodes of recurrence were 2.1 times per patient (range 1 to 5). Function of the remnant kidney in most patients was unchanged during followup. However, 2 of the 15 patients with recurrent stones had anuria during the acute attack of renal colic and, thus, required percutaneous nephrostomy urinary diversion, while 1 had proteinuria (3 gm. per day) and progressive renal failure 47 months after nephrectomy. The metabolic stone patients seemed to experience recurrence more easily than metabolic stone patients seemed to experience recurrence more easily than infection stone patients (37% versus 13%) but no statistically significant difference was noted (p = 0.198).

Adult↗
PubMed1994

A technique for simultaneous replantation of multiple amputated digits at Tamai's Zone V.

A technique for simultaneously replanting multiple digits amputated at Tamai's Zone V is described. Since these multiple amputated digits are connected together, they should be replanted as a single unit. The technique includes applying the pneumatic tourniquet first, debridement, bone shortening, and fixation of all the amputated digits, including tendon repairs, application of vascular clamps before releasing the tourniquet, followed by vascular anastomosis in one-by-one fashion for each digit. The disadvantage of this technique is the difficulty in keeping the digit cool. The advantages are it is a less time-consuming operation, there is reduced blood loss and contamination, and there is a better axial arrangement of the bony framework.

Adolescent↗
PubMed1994

Reappraisal of scrotal scintigraphy in evaluation of varicocoeles.

Varicocoeles could be classified into stop-type and shunt-type. In stop-type varicocoeles, only the internal spermatic (testicular) vein is dilated and needs to be ligated. In shunt-type, both internal spermatic vein and external spermatic (cremasteric) vein are dilated due to incompetence of the cremasteric system and both venous systems require ligation. Two-phase (flow and static) scrotal scintigraphy was performed on 92 patients preoperatively. Forty-three patients in whom the testicular and cremasteric veins could be verified during operation were included in this study. All 43 patients had unilateral varicocoeles and had abnormal blood pooling in the affected spermatic cord and hemiscrotum. In the blood flow study, 22 of 27 shunt-type varicocoeles had abnormal flow in the spermatic cord whereas only one out of 16 stop-type varicocoeles had increased blood flow. No difference in the results of semen analysis was found between the two groups of patients. Two-phase scrotal scintigraphy provides a noninvasive evaluation of shunting of the retrograde venous flow from the internal spermatic to the external spermatic vein. Understanding this pathophysiological change would be of benefit in the decision making about a surgical approach to varicocoeles.

Humans↗
PubMed1994

Traumatic asphyxia.

Four patients showing classic physical stigmata of traumatic asphyxia were studied. Cervicofacial cyanosis and edema, subconjunctival hemorrhage, and multiple ecchymotic hemorrhage of the face, neck, and upper part of the chest were documented. Admission Glasgow coma scale scores ranged from 8 to 15. All but one had no associated injury. Skin discoloration resolved within 3 weeks. Complete resolution of subconjunctival hemorrhage occurred 1 month later. In our series, sore throat, hoarseness, dizziness, numbness, and headaches were common. Profound lower leg pitting edema, hemoptysis, hemotympanum, and transient visual loss were noted. Chest radiographic findings were normal in all patients. Microscopic hematuria was noted in one patient. Diagnosis is made from the history and characteristic appearance of the patient. Treatment is directed to the associated injury. Oxygen supplement with head elevation to 30 degrees is the mainstay of treatment. If the patient survives the initial insult, the prognosis is excellent.

Adolescent↗
PubMed1994

Morphological change in the urothelium after electrohydraulic versus pulsed dye laser lithotripsy.

OBJECTIVE: To observe morphological changes in the urothelium after exposure to laser beam and electrohydraulic spark. MATERIALS AND METHODS: The pulse dye laser lithotripter (MDL-2, Candela Corporation, Boston, USA) and the electrohydraulic lithotripter (AEH-2, Circon ACMI Corporation Stamford, USA) were used directly on the bladder mucosa in six pigs. Immediately after treatment, the bladder mucosa was prepared for light microscopic and scanning electron microscopic examination. RESULTS: Both electrohydraulic spark and laser beam caused mucosal denudation, submucosal swelling and haemorrhage. There was a positive correlation between the degree of urothelial damage and the power and pulse numbers applied. CONCLUSION: Direct contact of the urothelium in patients treated with laser beam or electrohydraulic spark should be avoided.

Animals↗