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Biomedical subjects

K Choi

Publications and source records attributed to K Choi.

At least 91 records · Page 5Linked to original sources
PubMed1988

Tumors and tumor-like conditions of the middle ear and mastoid: role of CT and MRI. An analysis of 100 cases.

CT and MRI scanning provide valuable information in determining location and extension of middle ear and mastoid tumors and tumor-like conditions. The bone anatomy depicted by CT better delineates the involvement of the middle ear diseases. In glomus tumors, facial nerve tumors, and other cases including temporal bone metastases, the combination of CT and MR imaging is exceedingly useful in the diagnosis and management of patients.

Cranial Nerve Neoplasms↗
PubMed1987

Treatment of advanced bladder carcinoma with irradiation and concomitant 5-fluorouracil infusion.

Nineteen patients with locally advanced bladder cancer were treated with irradiation and concomitant 5-fluorouracil intravenous infusion with or without bolus mitomycin. Eighteen of the 19 patients were evaluated for local response. Eleven of the 18 patients (61%) obtained a complete local response within 3 to 6 months. An additional five patients (28%) showed tumor regression to a superficial state controlled by local transurethral resection and intravesical chemotherapy making the overall local clearance rate 16/18 (89%). The remaining two patients (11%) required salvage cystectomy for persistent disease and presently show no evidence of disease. Nine patients have died. Two patients died of intercurrent disease, six patients died of metastatic disease, and one patient who died from regional disease showed no evidence of local bladder tumor at the time of death. Berkson-Gage life-table analysis yields an adjusted survival of 62.5% at 5 years. Late complications included five patients with hemorrhagic cystitis, two patients with a contracted bladder, and one patient with a hemorrhagic radiation proctitis.

Aged↗
PubMed1986

Phase I clinical and pharmacokinetic study of bisantrene in refractory pediatric solid tumors.

Fourteen patients with pediatric malignant solid tumors, median age 15 years, received 22 courses of bisantrene in a Phase I study. Dosage escalations ranged from 10 to 120 mg/m2 daily for 5 consecutive days. Toxicity included myelosuppression and phlebitis. A sensitive (detection limit of 2 ng/ml) and specific HPLC method was developed to quantitate bisantrene in patient's plasma and urine. Peak plasma concentrations at the end of 60 minute infusions ranged from 568 ng/ml at 10 mg/m2 to 6800 ng/ml at the 100 mg/m2 dosage. The elimination half life (T 1/2 beta) averaged about 10 hours but increased to 20 hours in a patient with liver disease. Only 2.4 - 10% of the bisantrene dose was eliminated in the urine suggesting that the liver may be the major route of elimination for this antineoplastic anthracene derivative.

Adolescent↗
PubMed1986

Complications of combined radical hysterectomy and pelvic radiation.

Long-term gastrointestinal (GI) and urinary tract (UT) complications were evaluated in 48 women treated by radical hysterectomy (RH) and pelvic node dissection (PND) and in 25 women who received 5000-5400 rad of external pelvic radiation (RT) after RH-PND. No major complications developed in the surgery-only group, but the 5-year minor GI complication rate was 4% and the 5-year minor UT complication rate was 10%. In 9 patients receiving RT at 200 rad/day, one major GI complication (13%) and one major UT complication (14%) developed. In 16 patients receiving RT at 180 rad/day only minor GI complications (7%) and minor UT complications (13%) developed. The conclusion is that after RH-PND, adjunctive RT delivered at 180 rad/day through four ports results in acceptable, minimal complications.

Adult↗
PubMed1986

Response of colo-rectal hepatic metastases to concomitant radiotherapy and intravenous infusion 5 fluorouracil.

Twenty-three patients with colo-rectal hepatic metastases were retrospectively reviewed after completing treatment with split course liver irradiation and continually infused concomitant intravenous 5-fluorouracil. Although no patient attained a complete response, an objective partial response was documented in 15 (Responders). The Responders had a median survival of 45 weeks whereas Non-responders had a median survival of 17 weeks. Patients with metastatic disease solely in the liver or those with a Karnofsky performance score (k.p.s) of over sixty, had a median survival of 49 weeks. Patients with multiple organ metastatic involvement had a median survival of 25 weeks and those with a Karnofsky with less than 60 had a median survival of 27 weeks. (p values of 0.006 and 0.03, respectively.) The overall survival of the group completing treatment was 30 weeks, and 19 patients (83%) achieved subjective palliation. The patients tolerated therapy well. There was minimal hematological toxicity; 3 patients developed a leucocyte count of less than 2000 and 1 developed a platelet count of 30,000. The palliation and prolongation of survival attained with minimal complications suggest that adjuvant liver irradiation with concomitant infusion 5-fluorouracil radiosensitization may be an option to offer patients identified to be at high risk of developing subclinical liver disease.

Adult↗
PubMed1986

Inhibition of chemically induced mammary carcinogenesis in rats by long-term exposure to butylated hydroxytoluene (BHT): interrelations among BHT concentration, carcinogen dose, and diet.

In outbred female Sprague-Dawley rats long-term exposure to dietary butylated hydroxytoluene [3,5-di-tert-butyl-4-hydroxytoluene (BHT); CAS: 128-37-0] 1 week before carcinogen administration to termination resulted in a dose-related inhibition of mammary tumorigenesis and adrenocortical nodulogenesis. In animals fed the cereal-based NIH-07 diet and receiving a low dose (5 mg/rat) of 7,12-dimethylbenz [a] anthracene [(DBMA) CAS: 57-97-6], there was a significant overall inhibitory trend in tumor incidence observed among those receiving 300, 1,000, 3,000, and 6,000 ppm BHT. Maximal inhibition was approximately 50% at the highest concentration of BHT (6,000 ppm). The inhibitory effect of BHT on mammary tumor incidence was less pronounced when BHT was administered to rats initiated with a high carcinogen dose: At 15 mg DMBA/rat maximal inhibition was only 20% at the highest concentration of BHT (6,000 ppm). In contrast, when tumor yield was assessed in terms of latency or tumor multiplicity, the inhibitory effect of BHT was more pronounced in the groups given a high dose of DMBA than in the groups given a low dose. In animals given a low dose of DMBA (5 mg) and fed 6,000 ppm BHT in the casein-based AIN-76A diet, tumor incidence was inhibited by 50% of that of the controls; in contrast, when initiation was with a high dose of DMBA (15 mg), tumor incidence was decreased by only 28% of that of the controls. In animals fed the NIH-07 diet, DMBA-induced adrenocortical nodule formation was also inhibited in a dose-dependent fashion by BHT. At 5 mg DMBA maximal inhibition was 86% of control levels (6,000 ppm BHT); at 15 mg DMBA maximal inhibition was 66% of control levels (6,000 ppm BHT). However, when BHT was incorporated into the AIN-76A diet, its inhibitory effects on adrenocortical nodulogenesis were unexpectedly feeble and unrelated to carcinogen dose: In animals initiated with 5 mg DMBA and administered 6,000 ppm BHT, nodule incidence was decreased by only 25%, whereas in animals initiated with 15 mg DMBA, nodule incidence was decreased by 30% of that of the controls. These results indicate that while chronic exposure to dietary BHT suppressed the development of DMBA-induced mammary tumors and adrenocortical nodules, the degree of suppression depended on the dose of carcinogen administered, the level of BHT in the diet, and the parameter being measured. Diet-dependent differences in BHT action were observed with regard to DMBA-induced adrenocortical nodulogenesis but not with regard to mammary tumorigenesis.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1986

Comparison of 32P therapy and sequential hemibody irradiation (HBI) for bony metastases as methods of whole body irradiation.

We report a retrospective study of 15 patients with prostate carcinoma and diffuse bone metastases treated with sodium 32P for palliation of pain at Downstate Medical Center and Kings County Hospital from 1973 to 1978. The response rates, duration of response, and toxicities are compared with those of other series of patients treated with 32P and with sequential hemibody irradiation. The response rates and duration of response are similar with both modalities ranging from 58 to 95% with a duration of 3.3 to 6 months with 32P and from 75 to 86% with a median duration of 5.5 months with hemibody irradiation. There are significant differences in the patterns of response and in the toxicities of the two treatment methods. Both methods cause significant bone marrow depression. Acute radiation syndrome, radiation pneumonitis, and alopecia are seen with sequential hemibody irradiation and not with 32P, but their incidence can be reduced by careful treatment planning. Hemibody irradiation can provide pain relief within 24 to 48 h, while 32P may produce an initial exacerbation of pain. Lower hemibody irradiation alone is less toxic than either upper hemibody irradiation or 32P treatment.

Bone Neoplasms↗
PubMed1986

Dietary fat and mammary cancer. I. Promoting effects of different dietary fats on N-nitrosomethylurea-induced rat mammary tumorigenesis.

The promoting effects of diets varying both in type and amount of fat on N-nitrosomethylurea [(NMU) CAS: 684-93-5]-induced mammary tumorigenesis were assessed in female inbred F344 rats. Two seed oils (safflower and corn) and two fruit oils (olive and coconut), varying widely in their diene, monoene, and saturated fatty acid ratios, were fed in the casein-based AIN-76A diets at 23% [high-fat (HF) diet] and 5% [low-fat (LF) diet] by weight, with the exception of coconut oil which was fed only at 23%. The predominant fatty acid in safflower and corn oils was linoleic acid (82 and 56%, respectively), while the predominant fatty acids in olive and coconut oils were oleic (79%) and myristic (54%), respectively. The test diets were fed beginning 2 days after administration of NMU and continued until termination of the experiment at 22 weeks post NMU administration. Analysis of tumor incidence, latency, and multiplicity data obtained from the 7 experimental groups indicated that animals fed the HF safflower and corn oil diets exhibited enhanced mammary tumor yields when compared to animals fed HF olive or coconut oil diets or their LF counterparts. Since weight gains and total caloric intake were similar in all 4 HF groups, the results of this study indicate that the tumor-promoting properties of HF diets are more of a function of differences in fatty acid composition than of fat content per se or of total caloric intake.

Animals↗
PubMed1986

Dietary fat and mammary cancer. II. Modulation of serum and tumor lipid composition and tumor prostaglandins by different dietary fats: association with tumor incidence patterns.

For investigation of the role of linoleic acid (LA) and its biologically significant metabolites in mammary tumor promotion by dietary fat, a detailed study of the fatty acid group composition of serum lipids, tumor neutral lipids, tumor phospholipids, and tumor prostaglandins (PG's) was conducted in female inbred F344 rats initiated with N-nitrosomethylurea (CAS: 684-93-5) and fed diets containing various types and amounts of fat. The oils, safflower [23%, high fat (HF); 5%, low fat], corn (23%, 5%), olive (23%, 5%), and coconut (23%) varied widely with respect to their LA content and their polyunsaturate:monounsaturate:saturate ratios (9:1:1, 4.6:2.6:1, 0.6:5.9:1, and 0.008:0.05:1, respectively, for safflower, corn, olive, and coconut oils). A modified hexane-based technique was used for extraction of serum and tumor lipids. Total tumor lipids ranged from a low of 5 to a high of 228 mg/g (wet wt) with no differences found among the 7 dietary groups. The phospholipid content of the tumors ranged from 27 to 47% of total tumor lipid, again with no differences seen among dietary groups. Total serum lipids varied from a low of 3.77 mg/ml (safflower oil, 23%) to a high of 6.11 mg/ml (coconut oil, 23%), and an overall inverse trend was observed between total serum lipids and tumor incidence for the 4 HF diet groups. Serum cholesterol levels were significantly depressed in the HF safflower oil and corn oil groups compared to those in all other dietary groups and, in general, varied inversely with respect to mammary tumor incidence. Serum and tumor neutral fatty acid profiles closely reflected those of the diet, while tumor phospholipids appeared more resistant to diet-induced changes. Olive oil-fed animals exhibited high levels of oleic acid in both serum and tumor lipids. The levels of the major metabolite of LA, arachidonic acid (AA), in tumor phospholipids were highly variable and did not equate with dietary or serum LA levels. A positive association was found among dietary LA, tumor PGE2, and mammary tumor incidence among the 4 HF groups; however, no association was found between tumor AA levels and either tumor PGE2 levels or mammary tumor incidence. The results of this study suggest that dietary LA may exert its effects on mammary tumor promotion by virtue of its role as a PG precursor; but the precise steps in this sequence and possible competitive interactions between essential fatty acids, monoenes, and saturates and the PG-synthesizing system remain to be determined.

Animals↗
PubMed1986

Eicosanoids and metastasis: experimental aspects in Lewis lung carcinoma.

Lewis lung primary carcinomas have been extracted for eicosanoids, and the findings examined in relation to lung metastases. The order of the 5 compounds measured was PGE2 greater than PGE1 greater than PGF2 alpha greater than 6-keto-PGF1 alpha greater than TXB2. On the basis of the observation that the balance of PGI2 and TXA2 is altered in metastasis (Honn et al., 1983), the effects of Nafazatrom, a PGI2 enhancing agent, and imidazole, a thromboxane synthetase inhibitor, were tested. The experimental approach taken was to study spontaneous lung metastases after removal of the primary tumour at 13 days after tumour cell inoculation. Both Nafazatrom and imidazole decreased the lung weight when given during the period either before or after the excision of the primary tumour. There was a general trend toward an increase in the number of small lung nodules (greater than 2 mm) and a decrease in large lung nodules (greater than 2 mm) as a result of the chemotherapy. Mean survival time of the mice was significantly different among the five groups, with the mice surviving the longest in the group treated with Nafazatrom after the excision of the primary tumour.

Animals↗
PubMed1985

Dynamical axion.

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Journal Article↗