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Biomedical subjects

C T Chung

Publications and source records attributed to C T Chung.

At least 37 records · Page 2Linked to original sources
PubMed1989

Ethanol enhancement of isoproterenol-stimulated melatonin and cyclic AMP release from cultured pineal glands.

Norepinephrine stimulates the synthesis of melatonin in the pineal gland. The action of norepinephrine is believed to be mediated primarily by beta adrenergic receptors, and involves activation of adenylate cyclase. Ethanol, 25 to 50 mM, added to cultured pineal glands in vitro, enhanced isoproterenol-induced stimulation of cyclic AMP and melatonin production. The action of ethanol was observed only at doses of isoproterenol that produced a submaximal effect, and ethanol alone had no effect on cyclic AMP or melatonin release. Butanol, at a concentration of 2 mM, was as effective as 50 mM ethanol in increasing isoproterenol-stimulated cyclic AMP and melatonin release, indicating that the response to alcohols was not due simply to changes in osmolarity, and may reflect a hydrophobic interaction of the alcohols with the cell membrane. The effects of ethanol on pineal cyclic AMP and melatonin release were reversible after a 15-min preincubation, but not after a 2-hr preincubation, suggesting that, over a long incubation period, ethanol may sensitize the pineal beta adrenergic receptor-coupled adenylate cyclase system to isoproterenol. The findings in this study are consistent with earlier work showing that ethanol increases cerebral cortical beta adrenergic receptor-coupled adenylate cyclase activity, and demonstrate that the effect of ethanol on the receptor-effector system can result in an endocrinological response.

1-Butanol↗
PubMed1988

Air-fluid level in axillary vein simulating abscess.

Demonstration of an air-fluid level in the body wall on a computed tomography examination usually suggests the presence of an abscess or a postoperative fluid collection. However, the small amount of air that frequently is injected during intravenous contrast administration may result in a similar computed tomography appearance.

Abscess↗
PubMed1987

Controversy in the management of optic nerve glioma.

The records of 16 patients with optic nerve glioma treated between 1961 and 1984 were reviewed. All patients except two had extension of tumor beyond the chiasm to the hypothalamus, adjacent brain and/or along the posterior optic tract. Eleven of 16 cases were biopsy-proven, two patients had craniotomy and visual inspection but no biopsy was performed, and in two cases the biopsy was not diagnostic. Fourteen patients received radiation therapy, usually consisting of 50 Gy in 5 weeks (range 40-56 Gy), one patient was treated surgically and one with chemotherapy. With a follow-up of 1 to 20 years, 7 of the 14 patients irradiated are alive, three patients are dead of disease at 3, 6 and 9 years post-treatment, three were lost to follow-up at 1, 8, and 8 years, and one is dead of intercurrent disease at 5.5 years. Overall vision was improved in five patients and stable in seven following treatment. In two patients, vision could not be evaluated because of young age at presentation. Four patients had recurrences. One was retreated with 30 Gy in 3 weeks and shows no evidence of disease at 20 years. The three other patients died of their disease. There is controversy over the best treatment for these patients. Based on these results and a review of the literature, the authors recommendation is to irradiate tumors with extension beyond the chiasm at the time of presentation rather than waiting for increasing symptoms because function that is lost may not always be recovered. Chemotherapy needs to be further investigated but holds promise, especially for the younger children.

Adolescent↗
PubMed1987

Atypical distribution of Pneumocystis carinii infiltrates during radiation therapy.

Bilateral peripheral pulmonary infiltrates caused by Pneumocystis carinii developed in a patient undergoing mediastinal irradiation after chemotherapy for Hodgkin disease. The paramediastinal part of the lung included within the treatment port remained clear during the 2 1/2 weeks of radiation therapy. The distribution of the pneumocystis infiltrates was altered by the radiation, producing a pattern that is the "radiographic negative" of typical post-radiation therapy paramediastinal fibrosis.

Adult↗
PubMed1985

Bladder carcinoma. Experience with radical and preoperative radiotherapy in 421 patients.

Four hundred twenty-one patients with bladder carcinoma were treated with radical intent between 1968 and 1981: 356 were treated with irradiation alone with megavoltage tumor doses of 60-66 Gy delivered over a period of 6 to 7 weeks. Actuarial 5- and 10-year survival was 66% and 58% for Stage A (58 patients), 42% and 35% for Stage B1 (62 patients), 35% and 28% for Stage B2 (120 patients), and 23% and 19% for Stage C (75 patients), respectively. Five-year survival after salvage cystectomy (47 patients) was 51% from the time of surgery, with 4 operative mortalities and a major complication rate of 30%. Sixty-five patients were entered into an integrated preradical cystectomy irradiation program. Fifty-three patients in stages B2-C-D1 received high-dose preoperative radiotherapy (40-50 Gy) before a planned, delayed radical cystectomy. The actuarial 5-year survival was 66% for 65 patients, and 64% for the 53 patients in the high-dose precystectomy program; major complications were encountered in 34% and there were 2 mortalities. Five-year actuarial survival for Stage B2-C was 30% but fell to 24% when patients with salvage cystectomy were excluded. Distant metastasis was found in 30% of patients in Stage B2-C-D1, and also in the high-dose precystectomy program patients. Two-thirds of patients with distant metastasis in the radiation alone group were never considered for salvage cystectomy as they had distant metastasis alone, persistent disease with metastasis within 6 months after initiation of irradiation, or local recurrence and distant metastasis simultaneously. Early local recurrence may be salvaged in 50% to 60% of patients without a significant increase in mortality or major complications. Accordingly, a program of radical irradiation with salvage cystectomy may avoid loss of the bladder in 45% of patients in Stage B2-C-D1 without compromising overall survival.

Adult↗
PubMed1985

Thyrotoxic thyroiditis after radiotherapy for Hodgkin's disease.

Exposure of the thyroid gland to ionizing radiation has been associated with a variety of abnormalities. Among these are tardive hypothyroidism and an increased risk of developing thyroid nodules and cancer. Although acute thyroiditis has been known to complicate radioactive iodine 131 therapy, it has rarely been associated with external beam irradiation. Thyrotoxic painless thyroiditis developed in two patients after mantle-field irradiation for Hodgkin's disease.

Acute Disease↗
PubMed1984

Local excision and radiotherapy for cancer of the oral tongue. A preliminary report.

A group of 18 patients with squamous cell carcinoma of the mid one-third of the tongue was treated by local resection and planned postoperative radiotherapy between 1976 and 1980. Tumors 0.5 cm or greater in thickness were included; no patients had cervical adenopathy. Six were categorized as T1, 10 as T2 and two as T3. In eight patients, histologic review showed tumor extension at or near the resection margin, despite a tumor-free margin at frozen section, while in 10 patients the margins were clear. Local tumor control was achieved in 16 patients (89%). Two failures were evident within 3 months after completion of treatment. The relatively short follow-up of such a small series limits the conclusions from this preliminary study, but the excellent results thus far merit further study.

Adult↗
PubMed1984

Effects of ethanol, temperature, and endogenous regulatory factors on the characteristics of striatal opiate receptors.

Ethanol can alter the affinity of mouse striatal opiate receptors for their ligands, and the present studies were aimed at determining the importance of the receptor microenvironment for this effect of ethanol. Changing the temperature of the binding assay, and thus altering the properties of neuronal membrane lipids, resulted in changes in the observed affinity of striatal binding sites for dihydromorphine (DHM), but not for D-Ala2, D-Leu5-enkephalin (ENK). The changes in temperature also differentially altered the response of the two binding sites to ethanol. Two other factors that regulate opiate receptor affinity, Na+ and GTP, also affected the response to ethanol. High concentrations of ethanol were more effective at decreasing receptor affinity for both DHM and ENK when the binding assays were performed in the presence of GTP or Na+. In addition, at 37 degrees C and in the presence of GTP or Na+, DHM binding, but not ENK binding, was significantly inhibited by a low, physiologically attainable concentration of ethanol. Our results suggest that the response of opiate receptors to ethanol is influenced by the microenvironment of the receptors, including the physical state of the membrane lipids and/or by the nature of the interactions of receptors with "coupling proteins" within the membrane. The differential responses of mu and delta receptors to temperature and to ethanol suggest that these receptors reside in specific membrane environments. Under physiological conditions, several different factors may contribute to a selective action of ethanol on particular subtypes of opiate receptors.

Animals↗
PubMed1984

Dose enhancement in bone in electron beam therapy.

This study investigated dose to bone tissue in electron beam therapy. Measurements were made using films and thermoluminescent dosimeters in a polystyrene phantom containing bone inhomogeneity for 15-MeV, 12-MeV, and 9-MeV electron beams. An increase in dose of approximately 18%, 12%, and 11%, for the three electron energies respectively, relative to the dose in polystyrene, was found for bone material having an electron density (relative to water) of 1.73. Measurements were also made using films for 15- and 9-MeV electrons in a phantom with a mandibular bone and teeth. A dose enhancement in bone of approximately 10% and 7%, respectively, for the two energies was found in the phantom where the electron density of bone was about 1.60. These results suggest that injury to bone is possible in those clinical situations where high doses of electrons are used for therapy.

Bone and Bones↗
PubMed1984

External-beam irradiation of carcinoma of the penis.

Twenty-four patients with biopsy-proved squamous-cell carcinoma of the penis underwent external-beam radiation therapy between 1966 and 1980. Fifteen were treated for the primary tumor and 9 for metastatic inguinal lymphadenopathy; no patient received prophylactic nodal irradiation. Doses ranged from 4,500 rad (45 Gy)/15 fractions/3 wk. to 6,400 rad (64 Gy)/32 fractions/6 1/2 wk. Seven out of 9 tumors in stage I, 2/3 in stage II, and 1/3 in stage IV were controlled for three years. Control of fixed, inoperable groin nodes was poor, and none of these patients survived beyond 1 1/2 years.

Adult↗
PubMed1982

The changing role of external-beam irradiation in the management of malignant tumors of the major salivary glands.

Postoperative irradiation reduces the local recurrence rate for malignant salivary gland tumors. Less extensive surgery followed by immediate radiotherapy is possible without decreasing local control; moreover, cosmetic appearance and physiological function are preserved. Local tumor control was achieved in 16 out of 17 patients without gross tumor using a dose of 6,000 rad/6 wk. Combined photon and electron beams give better cosmetic and functional results than either modality alone. Irradiation with greater than or equal to 7,000 rad should be employed in unresectable cases and may effect tumor control.

Adult↗
PubMed1982

Treatment results of combined high-dose preoperative radiotherapy and surgery for oropharyngeal cancer.

Fifty eight patients receiving planned high-dose preoperative radiotherapy followed by en bloc oro-mandibular-cervical resection for oropharyngeal cancer were reviewed. These patients received continued close observation and care from both the Otolaryngology and Radiotherapy services. In light of the ongoing controversy of preoperative vs. postoperative radiotherapy, we present our data demonstrating the value of preoperative radiation. An overall tumor control rate of 66% was achieved, with an adjusted survival rate of 62%. This was not only for early lesions, but also in patients having advanced (T3, T4) tumor and/or nodal disease (N1-4). These figures are somewhat higher than expected from the literature. A review and discussion of the surgical complications are also presented.

Aged↗
PubMed1981

Computed tomography in the management of head and neck cancer.

Computed tomography is indispensable in determining the deeper extensions of tumors and proper treatment planning as well as in documentation of tumor resolution for lesions arising in the nasal cavity, paranasal sinuses, orbit, and salivary glands. In the hypopharynx and larynx, computed tomography provides information of differing degrees of value according to the clinical stage, site of origin, and usual therapeutic approach for each tissue. Detection of subclinical cervical adenopathy needs further investigation. Computed tomography has not been of particular value for lesions arising in the oral cavity and oropharynx.

Adult↗
PubMed1980

Prophylactic neck irradiation.

Treatment of subclinical cervical metastases from advanced squamous carcinomas of the nasopharynx, oropharynx, oral cavity, hypopharynx, and larynx remains contentious. Watchful waiting, elective neck surgery, and, more recently neck irradiation all have their advocates. The possibility of "sterilization" of the neck showing no clinical signs of metastasis has been especially appealing in concept. Wth this in mind, and by use of an external high-dose megavoltage technique, radiation therapy was used in 152 patients with clinically negative necks at the Upstate Medical Center from 1968 to 1977. Lymph node failures were extremely low (4%) when wide-field radiation ports were used and the primary lesion controlled.

Carcinoma, Squamous Cell↗
PubMed1980

Radiotherapy for carcinoma of the nasal cavity.

Twenty-five patients with primary epithelial carcinoma of the nasal cavity without nodal or distant metastases were treated by irradiation between 1967 and 1978. Small field, beam-directed techniques delivered 6,000 to 7,000 rads with conventional fractionation. Control of the primary tumor was achieved in 21 (84%) patients after irradiation. All five treatment failures (one infield only, three infield recurrence with lymph node metastases, and one regional cervical node metastasis) were evident within six months; all five patients died of cancer. The adjusted actuarial survival rate at three years was 76%. Failure in the untreated neck was only 5% when the primary carcinoma was controlled and 16% overall. The literature has been reviewed with attention to tumor control rates and survival.

Adenocarcinoma↗