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Biomedical subjects

R K Chiou

Publications and source records attributed to R K Chiou.

At least 37 records · Page 2Linked to original sources
PubMed1995

Placement of large suprapubic tube using peel-away introducer.

We describe a new method for placing a large suprapubic tube and report our experience with 56 patients. This method uses a specially designed fascial dilator and peel-away introducer to place an 18F Foley catheter suprapubically. In our experience the method is simple and effective for the exchange of a small suprapubic tube to an 18F Foley catheter, and for primary placement of a large suprapubic tube. It is easily performed at the bedside or during a minor procedure with the patient under local anesthesia.

Catheters, Indwelling↗
PubMed1994

Randomized comparison of balloon dilation and transurethral incision for treatment of symptomatic benign prostatic hyperplasia.

The concept of relieving the symptoms of benign prostatic hyperplasia (BPH) by dilating the urethral has existed for centuries. Thirty patients with a clinically estimated prostate gland size of 25 g or less were randomized to either balloon dilation (BDP) or transurethral incision of the prostate (TUIP). The mean pretreatment Madsen-Iverson symptom scores in the two groups were 15.0 +/- 4.9 (SD) and 15.4 +/- 4.4, respectively. The early response rates were 87% fo BDP and 86% for TUIP, with the mean symptom scores declining to 3.4 +/- 2.8 after dilation and 4.2 +/- 6.6 after incision. Among the 14 patients who initially responded to BDP, 2 have been lost to follow-up, 1 died of unrelated causes at 17 months with no urinary symptoms, 2 remain in response at 32 and 38 months, and the other 9 (75% of those available for evaluation) have developed recurrences. Among the 12 patents who responded to TUIP, 2 have been lost to follow-up, 8 remain in response at 14 to 48 months, and 2 (20%) developed recurrences by 44 months of follow-up. In the short term, both BDP and TUIP are effective for treating bladder outlet obstruction in men with relatively small prostates. However, the effect of dilation appears to be less durable than that of incision.

Aged↗
PubMed1993

The titanium intraprostatic stent: the United States experience.

This multicenter, cooperative study represents the initial United States experience using an expandable, titanium intraprostatic stent in 68 patients (60 to 93 years old). The stents were inserted under direct vision and expanded to 33F using a balloon catheter. All patients had a symptom score analysis, and underwent measurement of peak urine flow and rate and post-void residual urine volume as part of the initial evaluation. Patients were seen at approximately 1, 3, 6 and 18 months after stent insertion (mean followup 16 months). Of the 68 patients 38 presented in urinary retention. The type of anesthesia used included general anesthesia in 6 patients, spinal or epidural anesthesia in 24, intravenous sedation in 20 and intraurethral lidocaine only in 18. All patients were able to void spontaneously within 36 hours after stent insertion. Symptom scores decreased from 16.8 to 3.9, 6.3, 5.0, 5.7 and 3.2 at approximately 1, 3, 6, 12 and 18 months, respectively. Peak urine flow rate increased from 3.9 to 13.8, 11.5, 11.2, 12.4 and 14.4 ml. per second at approximately 1, 3, 6, 12 and 18 months, respectively. Post-void residual urine volume decreased from 74.4 to 30.1, 29.2, 19.8 and 40.2 ml. at approximately 1, 3, 6 and 12 months, respectively. Of the initial 68 patients 5 died of the underlying disorder (all voiding satisfactorily with the stent in place) and 17 underwent uneventful stent removal (10 for technical failure and 7 for treatment failure). Technical failures were secondary to either inaccurate positioning or improper stent sizing. Of the 58 patients with proper placement of the stent and no technical failures 46 (79%) had improvement in symptom scores and urine flow rate. Transient hematuria was noted in 43 patients (63%) and usually resolved within 48 hours. None of the 6 urinary tract infections (9%) was recurrent. In conclusion, the titanium intraprostatic stent, when properly placed, is a promising therapeutic alternative to prostatectomy or long-term catheterization in high risk obstructed patients or those in urinary retention. Studies are currently in progress to determine the long-term efficacy of this therapeutic modality.

Aged↗
PubMed1991

Study of the clinical thermoluminescent dosimeter in the direct measurement of radiation adsorbed dose for radioimmunotherapy.

One of the major obstacles facing radioimmunotherapy (RIT) is the lack of a device to measure directly tumor and normal tissue radiation absorbed dose. Calculations based on the clearance and imaging scans have several limitations; hence we design and fabricate a sheathed clinical thermoluminescent dosimeter (TLD) for the measurement of absorbed dose by implantation in humans. Preclinical studies are performed in nine normal rabbits. Complete blood count, body temperature monitoring, clinical observation and necropsy show no untoward effects from the TLD. Consistent bone marrow radiation doses are noted in the four rabbits receiving 131I-labeled monoclonal antibody A6H. By using up to 20 clinical TLDs in one sheath, it will be possible to determine macroscopic heterogeneities in organs undergoing RIT.

Animals↗
PubMed1991

The impact of tumor size on the efficacy of monoclonal antibody-targeted radiotherapy: studies using a nude mouse model with human renal cell carcinoma xenografts.

Monoclonal antibody (Mab)-targeted radiotherapy is a unique approach in cancer therapy. Multiple factors affect the success of treatment. Internal radiation dosimetry and mini-dose Mab-targeted radiotherapy studies reveal that tumor size affects the efficacy of treatment. For tumors with calculated weight greater than 400 mg., intravenous administration of 131I-labeled A6H or A6H-C5H combination delivers significantly less tumor radiation dose (2070 +/- 580 cGy/100 microCi) than those for tumors of weight less than 200 mg. (5260 +/- 2460 cGy/100 microCi). In the mini-dose (an average of 73 to 86 microCi) Mab-targeted radiotherapy study of 109 mice with small tumors (six, 12, or 19 days after implantation), tumors 12 days after implantation (approximately 60 mg. in weight) showed regression in all mice and in 62% of mice gross tumor elimination was observed. In contrast, mini-dose therapy at day 19 (tumor weights approximately 170 mg.) resulted in tumor regression and tumor elimination rates of 33% and 17% respectively. These studies suggest that Mab-targeted radiotherapy is more suitable for treating small tumors.

Animals↗
PubMed1990

Ureteral obstruction associated with prostate cancer: the outcome after percutaneous nephrostomy.

We retrospectively reviewed the outcome of 37 prostate cancer patients with ureteral obstruction treated by percutaneous nephrostomy. The over-all survival was 57% at 1 year and 29% at 2 years (median survival time 21 months). The 1 and 2-year survival rates of 15 patients with no prior hormonal therapy were 73 and 47%, respectively, while those of patients who had previously received hormonal therapy were 48 and 19%, respectively. Median survival times of these groups were 24 months and 12 months, respectively. Of 12 patients who had severe renal failure before percutaneous nephrostomy (serum creatinine greater than or equal to 6.9 mg. per dl.) 9 had an adequate return of renal function (serum creatinine less than 3 mg. per dl.) after drainage and 58% survived more than 1 year (median survival time 22 months). Percutaneous nephrostomy is safe and effective in relieving ureteral obstruction and reasonable survival can be achieved even in patients with renal failure. Percutaneous nephrostomy should be considered strongly in these patients.

Aged↗
PubMed1990

Balloon dilatation of the external urethral sphincter: a case study.

A new and simple endoscopic treatment procedure of external urethral sphincters is described. The external urethral sphincter was dilated with a balloon catheter 25mm in diameter in a multiple sclerosis patient; the sphincter spasticity made intermittent catheterization impossible. Post dilatation, the resistance to catheterization completely disappeared and the urethral pressure profile showed a dramatic fall in sphincteric pressure. This fall in sphincteric pressure has remained at a normal post dilatation level at the time of submission of this article (7 months).

Adult↗
PubMed1990

Cosmetic orchiectomy for prostate cancer.

With several effective therapeutic methods available for achieving androgen ablation, we must respect the psychological needs of our patients. The choice should ultimately be made by the patient after a thoughtful discussion of the advantages and disadvantages of various approaches. Cosmetic orchiectomy has the advantages of having the minimal morbidity of a simple operation, achieving the reliable result of androgen ablation and preserving the physical male organ without the risk of drug side effects and the dependence on patient compliance. In our experience, the operation is satisfactory both in achieving the therapeutic goal of androgen deprivation and in meeting the psychological needs of patients.

Humans↗
PubMed1989

Biodistribution and radioimmunoscintigraphy studies of renal cell carcinoma using tumor-preferential monoclonal antibodies and F(ab')2 fragments.

The in vivo localization of renal cell carcinoma-preferential monoclonal antibodies A6H, D5D, and C5H was evaluated and the biodistribution of F(ab')2 antibody fragments of A6H and the intact Mab were compared in over 100 nude mice. A6H localized well to most renal cell carcinoma xenografts studied; the median tumor to blood ratios ranged from 6.4 to 11.5 for various xenografts. C5H also localized well to most renal cell carcinoma xenografts tested. However, D5D did not localize well to renal cell carcinoma xenografts in vivo despite its highly restrictive in vitro reactivity. The F(ab')2 fragments of A6H produced higher tumor to blood ratios, which probably resulted from fast clearance of the fragments from the circulation. Preliminary results showed that indium-111 labeling may further improve imaging.

Animals↗
PubMed1988

Monoclonal antibody-targeted radiotherapy of renal cell carcinoma using a nude mouse model.

Radiation dosimetry and monoclonal antibody (MAB)-targeted radiotherapy studies were performed to evaluate the feasibility of using tumor-preferential MAB as targeting agents for internal radiotherapy of renal cell carcinoma (RCC). Two human RCC xenograft lines, TK-177G and TK-82, were established in nude mice and studied using MAB A6H as a targeting agent. This MAB has previously demonstrated excellent in vivo localization to RCC xenografts. Two doses of A6H (13 to 19 micrograms) labeled with iodine 131 (110 to 130 microCi) caused the tumor to regress or arrested the tumor growth in both xenografts. Similar doses (18 to 43 micrograms; 120 microCi) of 131I-labeled control MAB AFP-22 or of unlabeled A6H did not inhibit tumor growth. While most mice in the control groups had tumors greater than 250 mg in weight by day 43, none of the tumors in mice treated with 131I-labeled A6H grew to that size during the 3-month observation period. Sequential computerized scintigraphy was used to calculate the amount of radioisotope localized in tumor versus normal mouse tissue. Therapeutic doses of 131I-labeled A6H delivered a median calculated radiation dose of 38 cGy/microCi (range, 28 to 57) injected dose to RCC xenografts, and a median of 0.9 cGy/microCi to normal mouse tissues. These findings suggest that A6H is able to target radioisotopes highly specifically to RCC and achieve a therapeutic effect in the experimental setting.

Animals↗
PubMed1988

Endoscopic treatment of posterior urethral obliteration: long-term followup and comparison with transpubic urethroplasty.

We compare our results with the endoscopic management of posterior urethral obliteration in 8 patients to our previous experience with transpubic urethroplasty in 6 patients. Although most patients who underwent an endoscopic procedure required 2 or 3 followup internal urethrotomies within the first 2 to 10 months after treatment, 6 have remained free of stricture for more than 2 years after this initial period of aggressive endoscopic management. This finding suggests that total obliteration of the posterior urethra can be managed effectively by endoscopic techniques. Comparison of endoscopic treatment with transpubic urethroplasty revealed a decrease in operative time, blood loss and hospital stay with endoscopic management. We recommend that transpubic urethroplasty be reserved for patients in whom urethral continuity cannot be re-established with relatively safe and simple endourological techniques.

Adult↗
PubMed1988

Endourethroplasty in the management of complicated posterior urethral strictures.

A 2-step endourethroplasty was performed to repair complicated posterior urethral strictures in 3 patients. In the first procedure scar tissue was resected transurethrally to create a smooth grafting bed. In a second endourological procedure a piece of full thickness prepuce was grafted at the stricture site. An intraluminal balloon catheter was used to keep the skin graft in close contact with the resected area of the urethra. Of the patients 2 have remained free of stricture for more than 22 months and 1 has remained free of stricture for more than 12 months after endourethroplasty. The technique offers a promising alternative to open surgery in selected patients with complicated posterior urethral strictures.

Adult↗
PubMed1987

Prostatic specific antigen and prostatic acid phosphatase in the monitoring and staging of patients with prostatic cancer.

Serum prostatic specific antigen and prostatic acid phosphatase levels were measured retrospectively and evaluated in 357 men with benign prostatic hypertrophy and in 209 men with various stages of prostatic carcinoma. Although prostatic specific antigen values were elevated in 21 per cent of the patients with benign prostatic hypertrophy, the elevations usually were low and did not interfere with clinical interpretation. Prostatic specific antigen was elevated in 98 per cent of 86 men with active stage D2 disease; in 22 per cent of the men prostatic specific antigen was the only elevated marker. In contrast, prostatic acid phosphatase was the only elevated marker in 1 per cent of the patients with stage D2 disease and neither marker was elevated in 2 per cent. Among 74 patients in whom prostatic specific antigen and prostatic acid phosphatase determinations were made before radical prostatectomy, prostatic specific antigen was elevated substantially (greater than 10 ng. per ml.) in 59 per cent (26 of 44) with extracapsular disease and in only 7 per cent (2 of 30) without extracapsular disease. More importantly, of those 28 patients with substantially elevated prostatic specific antigen levels 26 (93 per cent) had extracapsular disease. Serial serum measurements showed that prostatic specific antigen either reflected or predicted clinical status in more than 97 per cent of the patients. We conclude that prostatic specific antigen is an excellent serum tumor marker for monitoring patients with prostatic carcinoma and that it surpasses prostatic acid phosphatase in this regard. Prostatic specific antigen also may be useful in staging prostatic carcinoma and it may change our attitudes significantly about the therapeutic responses to this cancer.

Acid Phosphatase↗