Biomedical subjects

M T Chen

Publications and source records attributed to M T Chen.

At least 109 records · Page 6Linked to original sources

PubMed1991

Reduction of calcium excretion in the stone-forming kidney in unilateral ureteral obstruction.

Thirteen urolithiasis patients with unilateral obstructive uropathy were treated with percutaneous nephrostomy (PCN) either for urinary diversion, endopyelotomy, nephrolithtotmy or chemolysis. After percutaneous nephrostomy, the individual urine volume, creatinine clearance (Ccr), urinary absolute and fractional excretions of sodium, potassium, calcium, magnesium and inorganic phosphate were measured separately in timed urine collections from a pigtail catheter and from the urethra. The data showed that Ccr and the absolute urinary excretions of sodium, potassium, calcium, magnesium and inorganic phosphate were significantly lower in the PCN kidney immediately or 2 days after relief of obstruction. The ratio of total urinary calcium excretion to urinary creatinine excretion in the obstructed kidney was significantly greater than that in the contralateral kidney. The fractional excretions of calcium and magnesium increased as renal function decreased. The results showed that when the total Ccr is below normal, the apparent excretion of urinary calcium will be underestimated. However, when the total Ccr of patients is within normal range, hypercalciuria may be detected adequately and thus favors early implementation of an appropriate therapeutic strategy.

Calcium↗

PubMed1991

Neobladder construction using completely detubularized sigmoid colon after radical cystoprostatectomy.

To improve the quality of life of the patient we used completely detubularized sigmoid colon for bladder reconstruction along with radical cystoprostatectomy in 6 men with invasive bladder cancer. Followup was 8 to 20 months. Postoperatively, all of the patients were continent during the day but only 4 (66.7%) were continent at night, although they had to awaken twice to remain dry. Neocystourethroscopy in 4 of the 6 patients revealed no tumor and no stricture at the urethrocolonic anastomosis. However, a stone in the neobladder was found in 1 patients. Urodynamic study of the neobladder showed a low pressure (mean 16.7 cm. water) at the filling phase of water cystometry and an adequate maximal urethral closure pressure (mean 52.0 cm. water) and functional profile length (mean 3.8 cm.). The uroflow rate in all patients was good (1 patient even had a maximal uroflow rate of 31 ml. per second). There was no reflux in any patient. One patient had intestinal obstruction 5 months postoperatively and died 5 months later of widespread metastasis. The remaining 5 patients are alive with a satisfactory quality of life. In conclusion, use of completely detubularized sigmoid colon may be an ideal operation for neobladder construction after radical cystoprostatectomy.

Adult↗

PubMed1991

Autonomic hyperreflexia in spinal cord injury patient during percutaneous nephrolithotomy for renal stone: a case report.

Autonomic hyperreflexia or autonomic dysreflexia is a syndrome seen in approximately 85% of all quadriplegic patients and constitutes the only medical emergency related to spinal cord injury. We report on a paraplegic patient with a C5 to C7 spinal cord injury who suffered autonomic hyperreflexia during percutaneous nephrolithotomy for a right renal stone. The reflex-induced hypertension subsided with termination of the operation, and administration of an alpha and beta-adrenergic blocking agent (labelatol hydrochloride). The stone was removed successfully by pyelolithotomy with the patient under general anesthesia 4 days later.

Adult↗

PubMed1991

The incidence and prognostic significance of humoral hypercalcemia in renal cell carcinoma.

This retrospective study was conducted to evaluate the incidence and prognostic significance of humoral hypercalcemia in 218 renal cell carcinoma patients during the last 20 years. Of 218 patients 20 (9.2%) were hypercalcemic, with serum calcium levels ranging from 10.7 to 16.0 mg./dl. The respective incidence of humoral hypercalcemia was 3% in patients with stage I, 5.9% with stage II, 14.1% with stage III and 18.9% with stage IV disease without bone metastasis. The survival curves between the hypercalcemic and eucalcemic groups among stages I to III cancer patients showed no statistical significance (p greater than 0.05). The survival curve deteriorated significantly in stage IV cancer patients with humoral hypercalcemia (p less than 0.005), with a median survival of 45.0 +/- 39.7 days versus 286.4 +/- 27.6 days in eucalcemic patients. No specific correlation was found between pathological cell type and humoral hypercalcemia.

Carcinoma, Renal Cell↗

PubMed1991

Prospective radionuclide renal function evaluation and its correlation with radiological findings in patients with Kock pouch urinary diversion.

In an attempt to understand better the status of renal function after Kock pouch urinary diversion we conducted a prospective evaluation of renal function in 25 patients using the radionuclide 131iodine-hippurate. Studies were done before, and at 1 month and every 6 months for 30 months postoperatively. The radionuclide results were then compared to excretory urography and contrast study of the reservoir. Our renal function study included the determination of individual and total effective renal plasma flow (ml. per minute), the time to maximal radioactivity over the kidney (peak time in minutes) and a renogram. The mean total (both kidneys) effective renal plasma flow rates before (25 patients) and at month 1 (19), month 6 (14), month 12 (12), month 18 (6), month 24 (6) and month 30 (7) after operation were 385.5 +/- 112.2, 310.5 +/- 109.9, 362.7 +/- 69.2, 442.0 +/- 97.5, 468.2 +/- 82.5, 405.7 +/- 70.6 and 414.0 +/- 65.1, respectively. A comparison of individual and total effective renal plasma flow before and after operation revealed that only the change of the flow at each or both sides of the kidney before and at 1 month after the operation reached statistically significant differences, respectively (p less than 0.05, paired t test). Postoperatively 5 of 6 patients with hydronephrosis had abnormal peak time and a third segment on the renogram was performed on the corresponding side of the kidney. No reflux was noted on contrast study of the reservoir of any patient followed for up to 30 months. In conclusion, the radionuclide renal function evaluation showed a significant decrease of renal function 1 month after Kock pouch diversion, then it resumed and remained stable (neither improved nor deteriorated) for 30 months. Also the abnormal peak time and third segment on the renogram usually implicated a dilated upper urinary tract.

Female↗

PubMed1991

Effect of stresses before slaughter on changes to the physiological, biochemical and physical characteristics of duck muscle.

1. This experiment was designed to study the effects of fasting and enforced exercise on the physiological, biochemical and physical characteristics of duck muscle. 2. Sixty 75-d-old male ducks weighing 3.0 +/- 0.2 kg were assigned to three treatments: a control, and an 8 and 24 h fast plus enforced exercise for 10 min. The ducks were then sacrificed and the carcass stored at 4 degrees C for 24 h. 3. Although the pH and serum lactate contents gradually increased with fasting time the responses were not significant. The ultimate pH was elevated and the lactate of breast and thigh muscles was lower in stressed birds. 4. The activity of lactic dehydrogenase was significantly increased by the stress, and the activities of creatine phosphokinase and alkaline phosphatase were also increased slightly. However, no effect was found on the ATPase activity of the myofibrillar protein of either breast or thigh muscle as a result of the stress. The ATPase activity of myofibrillar protein of breast muscle significantly increased with storage time. 5. The extractability of myofibrillar protein increased with storage time for all treatments. The SDS-PAGE patterns of myofibrillar proteins were also studied. 6. Consequently DFD-like muscle was observed in the breast and thigh muscles of ducks which had been stressed.

Adenosine Triphosphatases↗

PubMed1991

Colour duplex sonography in the assessment of impotence.

We present our experience with colour duplex sonography (Acuson 128) in the assessment of 83 impotent men. Cavernosal artery measurements were taken before and after the intracorporeal injection of papaverine. The peak velocities following papaverine injection correlated well with the degree of clinical response. Percentage diameter change corresponded with some groups of clinical erection grade, although it was not as good a discriminator as peak velocity. Twelve patients with 24 cavernosal arteries were also examined using pharmacological selective arteriography. Correlation between duplex sonography and arteriography showed an accuracy of 87.5%, specificity of 100.0% and sensitivity of 82.4%. All patients with a clinically good response following papaverine injection had peak bilateral cavernosal artery velocities greater than or equal to 25 cm/s. Amongst the remaining suboptimal responders, 18 also had this finding. Fifteen of these underwent pharmacological cavernosography and 14 exhibited venous leakage. Duplex sonography is a valuable and non-invasive tool in the assessment of impotence and can provide valuable information in deciding the course of further evaluation and treatment. The procedure was always completed more quickly with the guidance of colour Doppler.

Adult↗

PubMed1991

Incidental adenocarcinoma of the prostate: a retrospective analysis.

Between January 1980 and June 1990, 5875 patients underwent either TURP (5,529) or open prostatectomy (346) for the management of benign prostatic hyperplasia. Incidental carcinoma was identified in 53 patients (0.9%) - 49 in the TURP group and 4 in the open prostatectomy group. The overall incidence of stage A prostate carcinoma during the same period was 13.1% (53/406). Of those 50 regularly followed patients, only 6 (12.0%) underwent subsequent radical prostatectomy with pelvic lymphadenectomy, and residual tumors were identified in 4 patients (66.7%). The progression rate was 33.3% (3/9) in high-grade tumors (Gleason's score greater than 6) and 7.7% (2/26) in low-grade tumors (Gleason's score less than 5). In those 50 patients, 41 (82.0%) presented no evidence of disease and 9 (18.0%) stayed alive with progression. The mean length of follow-up was 34 months (range: 2-108 months). Our study demonstrates that the outcome of incidental carcinoma of the prostate is good. However, the residual tumor rate still remains high at 66.7%. Radical prostatectomy is recommended in young patients or in patients with high grade tumor.

Adenocarcinoma↗

PubMed1991

Serum iron as a tumor marker in renal cell carcinoma.

To evaluate the feasibility of using serum iron as a tumor marker for renal cell carcinoma, a retrospective review of serum iron, hemoglobin, hematocrit, mean corpuscular volume and pathology in patients with renal cell carcinoma was carried out. From January 1985 to December 1989, preoperative serum iron was obtained in 82 patients; 27 had stage I, 5 stage II, 23 stage III and 27 had stage IV disease. The serum iron levels (micrograms/dl) were 81.6 +/- 33.2 in stage I, 57.8 +/- 18.9 in stage II, 59.6 +/- 34.6 in stage III and 45.6 +/- 32.7 in stage IV disease, which were significantly lower as compared with the data (114.6 +/- 38.9) of a control group. Postoperative serum iron levels were available in 31 patients following nephrectomy and all showed an increase as compared with preoperative data except 2: 1 with recurrence and the other with progression of disease. It was concluded that the serum iron level may be used as a useful tumor marker in staging and follow-up of renal cell carcinoma.

Biomarkers, Tumor↗

PubMed1991

Experience with percutaneous nephrostomy, extracorporeal shock wave lithotripsy and chemolysis in the treatment of obstructive uric acid stones.

Intravenous pyelography (IVP), retrograde ureteral catheterization and percutaneous nephrostomy (PCN) have been used to locate radiolucent stones during ESWL in an X-ray localization system lithotripter. We also used an alternative method combining PCN, ESWL and chemolysis to treat 8 obstructive uric acid stones. The average number of shock wave pulses was 1,725 (range 1,000-2,000), the generator voltage of the HM-3 Dornier lithotripter was 20-22 kV, and the local chemolysis lasted 4 days (range 2-7). All radiolucent uric acid stones were successfully disintegrated. Of the 8 patients treated, 5 were completely free of stones and the other 3 had insignificant residual stones after 3 months. Three patients who developed fever during local chemolysis with 0.1 M sodium bicarbonate solution were managed conservatively without severe sequelae. Only 1 patient retained a PCN tube after discharge. Because PCN can provide a path for local chemolysis and better localization, it is especially helpful in treating obstructive uric acid stones.

Bicarbonates↗

PubMed1991

Penile brachial index in impotent patients with coronary artery disease.

From March to July 1989, a total of 40 patients, who had received coronary catheterization, answered questionnaires concerning sexual potency. In those 30 patients with a diseased coronary artery, only 2 (6.6%) had no erectile dysfunction subjectively. On the contrary, 4 of 10 (40%) patients with angiographically proven normal coronary artery complained of erectile dysfunction. Penile Doppler ultrasonography was performed in 30 patients. The mean penile brachial index (PBI) of 8 patients with a normal coronary artery was 0.82 +/- 0.1, as compared with the diseased group, 0.73 +/- 0.1 (p = 0.05). When these patients were further divided into two groups by a PBI of greater or less than 0.65, there was also no significant difference in the degree of obstruction of the three main coronary arteries between these two groups. There was no correlation between PBI and obstruction of the left anterior descending artery (r = 0.316, p = 0.689). Most of the patients (93.4%) with an abnormal coronary artery had erectile dysfunction. Nevertheless a poor correlation was noted between the PBI and the severity of coronary artery obstruction. Our study suggests that it is hard to use PBI alone as a predictor of future major thromboembolic heart attack.

Coronary Artery Disease↗

PubMed1991

Stone incrustation: a relevant complication of the intraprostatic spiral.

Six high operative risk patients with urinary retention caused by benign prostatic hyperplasia were managed with an intraprostatic spiral at our hospital. Three of them had severe coronary artery disease, 1 had uremia, 1 had cerebral stroke and 1 had poorly controlled diabetes mellitus. The urinary retention was successfully relieved by the intraprostatic spiral in all patients. No operative mortality or severe complication was encountered. One patient experienced a repeat attack of urinary retention due to proximal migration of the spiral. Four patients complained of urgency, which was relieved by anticholinergic agents. Stone incrustation was found on 2 out of 3 spirals removed (66%), and the stone turned out to be calcium phosphate and struvite by scanning electron microscopy and infrared spectrophotometry. In 1 patient, stone formation was so abundant that it almost obstructed the lumen of the redundant tip of the spiral. From our preliminary results, the intraprostatic spiral seems to be a good alternative to an indwelling catheter for patients awaiting prostatectomy. Nevertheless, the potential complication of stone incrustation should be anticipated and it is suggested to remove the device as soon as possible or to replace it at regular intervals.

Aged↗

PubMed1991

Factors influencing radiation exposure during the extracorporeal shock wave lithotripsy.

A prospective evaluation of 89 consecutive sessions of extracorporeal shock wave lithotripsy (ESWL) was undertaken to try and find the best way of minimising the amount of exposure to radiation. Forty-two patients were randomly allocated to undergo ESWL treatment by experienced surgeons (group A), and 47 to undergo the treatment by inexperienced surgeons (group B). The mean calculated entrance radiation exposure was 3.01 rads (group A: 2.64 (0.97) rads, range 1.00-4.48, group B: 3.38 (0.86) rads, range 1.11-5.75). Among factors that influenced radiation exposure, the tissue: air ratio should be borne in mind and the level of skill in controlling movement of gantry was the most important in reducing the exposure to radiation.

Adult↗

PubMed1991

[Idiopathic retroperitoneal fibrosis causing obstructive uropathy: a case report].

Idiopathic retroperitoneal fibrosis leading to obstructive uropathy is a rare disease in our country, so a typical case deserves presentation. The patient is a 56-year-old female to have a clinical manifestation of obstructive uropathy. Retrograde pyelogram permitted 5 Fr. ureteral catheter to pass the stenotic segment. At the mean-time, there was hydronephrosis, medial deviation and gradual thinning and pointing of the middle segment of the ureter (classic triad). Computed tomography revealed that retroperitoneal soft tissue plaque enveloped aorta, inferior vena cava, and bilateral ureters. The patient received ureterolysis with ureter intraperitonealization and lateralization. The plaque was pathologically proved fibrosis. Renal function became normal postoperatively.

Female↗

PubMed1991

Aldosterone-producing adenoma--variable serum aldosterone response to postural change: a case report.

A 25-year-old female was admitted for evaluation of hypertension and hypokalemia. Plasma renin activity was suppressed and plasma aldosterone level was higher than normal. The CT scan of adrenal gland revealed a 2.5cm in size low density tumor mass over right adrenal area, and NP-59 adrenal scan showed early and persistent uptake of radioactivity in the right adrenal gland. Interestingly, the plasma aldosterone level was elevated, decreased and unchanged to postural change on three different occasions. After right adrenalectomy, the plasma aldosterone level decreased to 4.77ng/dl, blood pressure, serum potassium, and plasma aldosterone returned to normal response to postural change. Histologically, it was compatible with the picture of cortical adenoma. However, the tumor cell may not have reached autonomous function yet, since different responses of plasma aldosterone to postural change were observed clinically.

Adenoma↗

PubMed1991

Radionuclide imaging clinical study. Corporeal 133Xe washout for detecting venous leakage in impotence.

A quantitative test, corporeal 133Xe washout, was developed to detect venogenic impotence. Data were acquired in frame mode after intracorporeal injection of 0.1 ml (1-2 mCi or 37-74 MBq) of 133Xe in saline on one side of the midline just behind the glans in the flaccid state for 20 min. A time-activity curve (TAC) was generated from the region of interest (ROI) at the site of injection and a computer routine was then used to calculate clearance half-time (T1/2) in minutes and flow rate (Q) in ml/100 g tissue/min from corporeal 133Xe clearance. The data from 12 controls and 21 patients with venous leakage were analysed. In patients with venogenic impotence, T1/2 (mean +/- S.D.) was greatly increased (24.4 +/- 10.7 min vs 10.7 +/- 4.6 min in controls, P less than 0.005) whereas Q markedly decreased (2.4 +/- 1.3 ml/100 g tissue/min vs 5.4 +/- 2.3 ml/100 g tissue/min in controls, P less than 0.005). The sensitivity and specificity for detecting venous leakage at the optimal threshold of T1/2 equal to 13 min and Q equal to 3.7 ml/100 g tissue/min were 95 and 75%, respectively. The corporeal 133Xe clearance half-time and flow rate are two simple and clinically useful indices for detecting venous leakage.

Adult↗

PubMed1991

Comparison between histopathology and DNA histogram of testis.

From January to July 1989, the DNA histogram of testicular open biopsies was done for 11 patients of primary infertility and 7 patients of a control group. There were 2 failures in these 36 specimens. The flow cytometric analysis revealed characteristic patterns in the relative numbers of haploid (1C), diploid (2C), and tetraploid (4C) cells. In the presence of normal spermatogenesis, the haploid compartment contained the majority of cells, followed by the diploid, and then the tetraploid (1C greater than 2C greater than 4C). The other diagnostic criteria of flow cytometry were as follows: hypospermatogenesis (2C greater than 1C greater than 4C), the maturation arrest (2C greater than 4C greater than 1C), and Sertoli-cell-only syndrome (2C, near 100%). According to the aforementioned diagnostic criteria, the results of DNA histograms were compared with the histopathology diagnosed by junior or senior pathologists. These patterns of DNA histograms correlated with the diagnoses by senior pathologists in 28 of 34 specimens (82.6%), while there were only 20 of 36 pathologic diagnoses (55.6%) which matched between junior and senior pathologists. It is shown that abundant experience is needed for testis pathologists to diagnose accurately. The DNA histograms correlate well with pathological findings, with the advantages of quantification and fewer specimens needed. In conclusion, testicular tubular cell DNA histograms appear to be a reliable modality in the evaluation of spermatogenesis. They provide the quantitative information of sperm maturation and help in making appropriate decisions in the management of male infertility.

DNA↗

PubMed1990

Clinical experience of Kock pouch continent urinary diversion.

Kock continent ileal reservoir for urinary diversion was performed in 53 patients with invasive bladder cancer (52) or neurogenic bladder (1). The postoperative follow-up period was from six to thirty-nine months. The clinical results showed no metabolic disturbance of blood electrolytes or acidity. Prolapse of efferent nipple valve developed in 4 patients (7.6%); and 2 underwent revisional surgery with a good result. Another 4 patients (7.6%) suffered from poor continence and relatively frequent catheterization to empty the pouch was necessary to prevent urine leakage through the stoma. Urodynamic study of the Kock pouch in these 4 patients showed a short functional nipple valve length and small pouch capacity. The other 45 patients (84.8%) had good continence. Urodynamic study of the pouch in 20 patients showed low pressure (mean of 13.3 cm H2O) in the pouch and high pressure (mean of 72.1 cm H2O) at the efferent nipple valve. Three patients had unilateral hydronephrosis in the follow-up intravenous urography. Corrective surgery for stenosis at the right ureteroileal anastomosis was done in 1 patient with normalization of the upper urinary tract afterward. The other 2 patients were managed by close observation for the mild hydronephrosis. Symptomatic bacteriuria developed in only 3 patients (5.7%) and responded well to antibiotic management. Reservoirography demonstrated no reflux into the upper urinary tract in all the follow-up patients. There was no significant change of the renal function at twenty-four months after operation detected by radionuclide (131I-Hippuran) renal functional study. All patients were satisfied with Kock urinary diversion.

Adolescent↗