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Biomedical subjects

T Viravathana

Publications and source records attributed to T Viravathana.

11 recordsLinked to original sources
PubMed1998

Radiation-induced enterocolitis: basic and applied science.

We adapted and introduced in our laboratory a simplified animal model of radiation-induced enterocolitis. After a shielding of the parenchymatous organs, our dose-response studies revealed that 20 Gy x-ray radiation resulted in about 20% mortality and reproducible lesions in the terminal ileum and proximal colon. These changes are optimal for pharmacologic studies since they may be decreased or aggravated by drugs. Sucralfate dose-dependently decreased the clinical signs of enterocolitis (e.g., lethargy, diarrhea) as well as the number and area of ileal and colonic erosions and ulcers. The wet weight of the ileum and colon were also decreased by sucralfate. bFGF at the small doses used exerted a beneficial effect only on a few of the parameters of enterocolitis. Thus sucralfate, and maybe bFGF, might decrease the severity and accelerate the healing of radiation-induced enterocolitis.

Animals↗
PubMed1989

Effect of radiation therapy on bronchial obstruction due to bronchogenic carcinoma.

We evaluated the effect of radiation therapy in 57 patients with obstruction of a large bronchus with NSCC. Response with aeration of the atelectatic lung was seen in 12 patients (21 percent). Three patients (5 percent) showed partial response with persistent partial atelectasis, and nine patients (16 percent) showed good response with complete aeration of the atelectatic lung. In these patients the response appeared to be related to the dose of radiation. All of the patients who responded received more than 50 Gy. The difference in the response rate related to the dose of radiation was statistically significant (p less than 0.05). The rates were similar with all histologic types of NSCC. Regardless of the clinical response observed, bronchoscopy performed two to four months after completion of radiation therapy in 14 patients revealed persistent endobronchial tumor. There was no significant relationship between the persistence of endobronchial tumor, the dose of radiation therapy, and the tumor's histologic type. Of the 12 patients with radiographic improvement in atelectasis, fibrotic changes developed in four (33 percent) patients and pneumonitis in two (17 percent). Progression of disease with distant metastases occurred in 58 percent (seven) of the 12 patients who showed a clinical response of their bronchial obstruction. The median time to survival was nearly identical in responders and nonresponders.

Aged↗
PubMed1983

Chemotherapy for metastatic basal cell carcinoma.

Metastatic basal cell carcinoma is a rare, malignant neoplasm associated with poor survival. A 63-year-old woman had an extensive primary keratinizing basal cell carcinoma of the scalp, with metastases to the regional lymph nodes of the neck. Disease in the primary site and in the regional lymph nodes was controlled by surgery and irradiation. However, skeletal metastases that responded to therapy with three courses of cisplatin and bleomycin sulfate and then to ten courses of cyclophosphamide, methotrexate, and fluorouracil developed. Subsequent progressive metastases failed to respond to a combined cisplatin and cyclophosphamide regimen as well as to etoposide and doxorubicin hydrochloride used as single agents.

Antineoplastic Agents↗
PubMed1982

Radiation treatment of carcinoma of the cervix with extension into the endometrium: a reappraisal of its significance.

During the period from 1969--1974, 561 patients with proven invasive squamous cell carcinoma of the cervix were treated by irradiation only in the Department of Radiation Therapy, University of Maryland Hospital. Of these, 82 patients were identified as having D & C positive for squamous cell cancer present in the curettings with or without endometrial tissue. Clinical staging was done using FIGO guidelines and the treatment of endometrial extension was the same as with regular cervical cancer. Of 82 cases who are eligible for a minimum five-year follow-up, the absolute five-year survival is as follows: Stage I, 68%, (17/25); Stage II, 62% (18/29); Stage III, 40% (10/25); Stage IV, 0% (0/3). The most interesting features are the local and distant failures in Stage I and II disease. Local failure in Stage I and II in this study is in line with other series. Distant metastasis, however, occurs at the rate of 20% in Stage I between 1--2 years after treatment (as compared to the control of 5%). In Stage II, the distant disease increases to 24% with a substantial number of local failure with distant metastasis. Based on our findings and others, it seems appropriate to suggest D &nd C be done routinely in order to identify the extension of cancer into the endometrium and treat them properly. Also it appears appropriate to re-examine our policy of the treatment to minimize both local and distant failures with suggestions outlined in Schema I and II along with possibility of a future chemotherapeutic management to minimize the distant disease.

Adult↗
PubMed1981

Irradiation of malignant tumors of the parotid gland.

The treatment results in a series of 30 patients with parotid gland carcinoma are reported. Postoperative irradiation to the parotid bed and regional lymph node appears to improve the result of treatment. No difference in the results or complications was found between the group of patients treated by external irradiation or external irradiation combined with radium implantation. Irradiation of residual disease was more effective than irradiation of the recurrences.

Adenocarcinoma↗
PubMed1980

Selective tumor heating by shortwave radiofrequency (RF).

Experimental solid tumors were treated in vivo with external high frequency dielectric heating to observe any heat selectivity between the tumor mass on one hand, and the subcutaneous tissue, muscle, and systemic temperatures on the other. Methylcholantrene-induced sarcoma cells were inoculated into the subcutaneous tissue or muscles of the posterior thigh of isologous Fischer rats. When the tumor mass reached the desired size, dielectric heating with a fixed frequency of 13.56 megahertz (MHz) was applied locally to the tumor-bearing area. All the periods of treatment were kept constant at 1 hour. Temperature was measured with thermocouple probes inserted directly into the tumor mass and the tissues lying within the electromagnetic field. Systemic temperature was monitored via a clinical mercury thermometer inserted into the rectum. Temperature recordings were taken at 5-minute intervals during which time the power was turned off in order to avoid the RF interference and to allow thermal equilibrium between the probes and the tissue. The results showed a high selective temperature gradient for the tumor mass as compared to the subcutaneous and muscle tissues when tumor masses were greater than 1.0 cu cm. No selectivity was detected in small tumors or in nontumor-bearing controls. Systemic temperature did not rise by these treatments. No tumor regression was observed at this dosage. Burns were noted in those animals in which normal tissue temperature rose above 43 C.

Animals↗
PubMed1980

Technique and dosimetry in the management of extensive basal-cell carcinomas of the head and neck region by irradiation with electron beams.

The use of irradiation by electron beam in the treatment of four cases of extensive basal-cell carcinomas of the skin of the head and neck is described. The technique of treatment is simple, convenient, well tolerated, and the treatment has good cosmetic and functional results. Local control has been excellent in the cases treated and there have been no complications from the electron-beam therapy.

Aged↗
PubMed1977

Radiation management of primary carcinoma of the vagina.

This 15-year retrospective study includes 71 patients with diagnosis of primary carcinoma of the vagina treated at the University of Maryland Hospital, Radiation Therapy section from 1957 to 1970. The lesions were staged according to the system advocated by International Federation of Gynecology and Obstetrics (FIGO) with a minor modification (Perez et al.11). With the exception of Stage O, histologic diagnosis was 94% (60/64) invasive squamous cell carcinoma and 6.0% (4/64) adenocarcinoma. Of 71 cases who are eligible for a minimum five-year follow-up, the absolute five-year cure rate for various clinical stages is as follows: Stage O 100% (7/7), Stage 1 83.2% (5/6), Stage 11A 65% (13/20), Stage 11B 63.5% (7/11), Stage 111 40% (8/20), Stage IV 0% (0/7). The overall absolute five-year cure-rate for all stages combined was 56.3% (40/71). A comparable result and even better in some stages (II and III) as compared to several previous reports are thought to be due to the proper intergrated irradiation combining interstitial and intracavitary radium with external super-voltage beam. Furthermore, an aggressive radium implant to the vagina, paracolpium, and specifically to parametrium and pelvic wall in Stage II and III appears to be one of the keys to our good results. The technique of treatment, stage by stage, are being fully discussed along with a few complications and failures.

Adenocarcinoma↗
PubMedDate not supplied

Combination chemotherapy for advanced squamous cell carcinoma of the head and neck.

Fifty-one patients (32 previously untreated, 19 previously treated) with advanced squamous cell carcinoma of the head and neck received a single course of combination chemotherapy consisting of high dose cis-platinum (DDP), bleomycin (Bleo), +/- high dose methotrexate (MTX). Thirty-three (65%) patients responded to therapy; 5 (10%) of these patients had a complete response. Previously untreated patients and those who received the three drugs (DDP, Bleo and MTX) had the highest response rates. The duration of response was 8 to 12 weeks. Seven (15%) patients showed a two-year survival rate. All nonresponders were dead of disease within two years. Three (56%) of the five complete-response patients and 4 (21%) of the partial-response patients survived for two years. The role of preoperative chemotherapy in head and neck cancer is yet to be conclusively defined.

Adult↗
PubMedDate not supplied

A therapeutic approach to early vocal cord carcinoma.

One hundred and twenty patients with early glottic carcinoma received radiation therapy at the University of Maryland Hospital from 1959 to 1977. The radiation dose ranged from 55 Gy in 4 weeks for small T1a lesions to 65 Gy in 61/2 weeks for T2 lesions. The local control rates by irradiation alone for stages T1a, T1b, and T2 were 92, 91 and 88 per cent, respectively, while 5-year determinate disease-free survival rates were 96 per cent for stage I disease and 88 per cent for stage II disease. Most of the local failures were salvaged by surgery, with a low complication rate. Regional metastases were uncommon, and occurred in 7 per cent in stage I and in 6 per cent in stage II disease. Factors increasing the risk of failures appeared to be bulky tumor, anterior commissure involvement and subglottic extension.

Adult↗