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Biomedical subjects

R G Martin

Publications and source records attributed to R G Martin.

At least 145 records · Page 8Linked to original sources
PubMed1975

Influence of staging celiotomy in localized presentations of Hodgkin's disease.

Staging celiotomy was performed in 139 previously untreated patients with lymphogram negative Stage I and II Hodgkin's disease. Sixteen additional patients received definitive radiotherapy for symptomatic relief of upper torso disease prior to abdominal exploration. The overall incidence of positive abdominal findings for these two groups was 34.5% and 31.2%, respectively. Further analysis of the 139 previously untreated cases revealed notable differences in incidence of positive abdominal findings for stage, presentation, and specific histology. Stage I patients with upper cervical or inguinal presentations or a lymphocytic predominance classification had negative celiotomies, as contrasted with a 43% incidence of positive abdominal findings in patients with supraclavicular presentations. In Stage II disease, the incidence of positive findings was related to the status of the mediastinum. For mediastinal presentations, the incidence was 33.3%, as compared to 48% for nonmediastinal presentations. To date, the number of relapses in celiotomy Stage I and II patients has been low regardless of whether or not prophylactic irradiation was administered to the major lymph-node-bearing regions of the upper and lower torso. Of 9 patients with progression, extranodal spread occurred as the first evidence of new disease in 4 patients. The implication of this finding is considered in a discussion on the influence of staging celiotomy in the management of Stage I and II patients with Hodgkin's disease.

Abdominal Neoplasms↗
PubMed1975

Sarcoma of soft tissue: clinical and histopathologic parameters and response to treatment.

Radical dose radiation therapy alone or combined with limited surgery has been employed in the management of 100 patients with primary (71) and recurrent (29) sarcoma of soft tissue. Results of this experience show that a combination of conservative surgery and radiation therapy, based upon radical dose levels and sophisticated techniques, is effective: only 13 of 100 patients showed local regrowth during a followup of 2-12 years. This may be compared with an expected congruent to 25 recurrences had treatment been radical surgery (wide resection or amputation). For lesions located on the distal extremities (elbow-hand, knee-foot) there were local failures in only 3 of 59 (5 percent). Further, 75 percent of patients treated by the improved techniques utilized in the recent 8 years retained a useful limb which is free of pain or edema. Histopathologic grade is demonstrated to be an important indicator of prognosis of local recurrence and of disease-free survival. Local recurrence rates were 0/23, 9/53, and 4/24 for Grades 1, 2, and 3. Disease-free survival rates were 19/23 (86 percent), 27/53 (51 percent), and 4/24 (17 percent) for Grades 1, 2, and 3, respectively. Invasion of skin appeared to be a sign of poor prognosis; 8 of 9 such patients developed distant metastases.

Abdominal Neoplasms↗
PubMed1975

Radiation-related pericarditis.

To determine the incidence of pericardial effusion in patients undergoing upper mantle radiation therapy, 81 patients with Hodgkin's disease, stages I to IIIB, were selected from a protocol series of 98 patients. Twenty-four patients (29.6 percent) met X-ray criteria for the presence of pericardial effusion. Eleven of the 24 also underwent right heart catheterization to confirm the presence of pericardial effusion and to define any hemodynamic abnormality. Fourteen patients were found to have transient effusion. Five of the 11 patients have had partial pericardiectomy for symptoms and signs of cardiac tamponade. There has been no evidence of recurrent Hodgkin's disease in these surgically treated patients. Ninety-two percent of the pericardial effusions occurred in the first 12 months after the end of radiation therapy. Therapeutic implications depend on elucidation of the natural history of this process. At present close follow-up is necessary with surgical intervention for signs or symptoms of cardiac tamponade.

Cardiac Catheterization↗
PubMed1975

Radiation-related pericardial effusions in patients with Hodgkin's disease.

Pericardial effusions following radiotherapy for Hodgkins Disease have previously been described as infrequent and related to the total dose of radiation received. Analysis of all chest x-rays on 81 patients who received upper-mantle radiotherapy for Hodgkins Disease at the Baltimore Cancer Research Center between 1968 and 1972 disclosed an incidence of pericardial effusions of 30.9% (25 of 81), with 13.6% (11 of 81) requiring limitation of activity (5) or pericardiectomy (6). Clinical presentation of radiation-related percardial effusions was subtle, with signs and symptoms a late finding if they occurred. Radiotherapy data was reviewed and no difference in total dose (rads) or time-dose relationships (rets) was found between the groups who did or did not develop effusions. Analysis of multiple pre-treatment clinical and pathological characteristics disclosed four parameters that were felt to be related to the development of pericardial effusions; elevated ESR, normal absolute lymphocyte count, initial presence of extensive mediastinal adenopathy and the addition of adjuvant chemotherapy. The presence of increasing combinations of these pretreatment 'risk factors' led to an increasing likelihood of developing a radiation-related pericardial effusion such that six of seven patients with all four 'risk factors' developed a pericardial effusion. Nine of 13 clinically significant effusions were associated with the addition of adjuvant chemotherapy. Possible pathogenetic mechanisms that include factors other than radiation dosage and the clinical management of radiation-related pericardial effusions are discussed.

Adult↗
PubMed1975

Products of complementation between temperature-sensitive mutants of simian virus 40.

Temperature-sensitive mutants of the D complementation group of simian virus 40 exhibit delayed complementation. Analysis of the thermal stability, kinetic profiles in temperature shift experiments, and progeny of complementation have led to the hypothesis that delayed complementation is not true complementation, but the result of a very low level of leakiness, followed by phenotypic mixing of the progeny D mutants. This hypothesis is consistent with the proposal that D mutants are defective in uncoating. In the course of these experiments, it was observed that fresh medium suppresses the growth of D mutants at the restrictive temperature.

Animals↗
PubMed1975

DNA infectivity and the induction of host DNA synthesis with temperature-sensitive mutants of simian virus 40.

Host DNA synthesis is induced when CV-1 (monkey kidney) cell cultures are infected at 40 C with wild-type virions or with temperature-sensitive Simian virus 40 mutants of the "early" complementation group A. Host DNA synthesis is not induced when cultures are infected with mutants of the late complementation group D. The simplest explanation for these observations, that induction depends not upon the expression of some early gene function but rather on the presence of an active D protein in the infecting virion, has been examined. Indirect experiments suggest that this explanation is not correct. Moreover, the induction of host DNA synthesis is impaired when cultures are infected with mutants of the A group at 42.5 C rather than 40 C, suggesting that the A function may be responsible for host induction. The inability of D virions to induce host DNA synthesis may reflect their inability to "uncoat" at 40C.

Animals↗
PubMed1975

Simian virus 40 functions required for the establishment and maintenance of malignant transformation.

Members of the five classes of temperature-sensitive simian virus 40 mutants were tested for their ability to transform Chinese hamster lung cells. Two criteria for transformation were used: the ability to form clones in medium with low serum concentrations and the ability to overgrow a monolayer. Only A mutants failed to transform at the restrictive temperature when subconfluent Chinese hamster lung monolayers were used. However, both A and D mutants failed to transform at the restrictive temperature when confluent monolayers and depleted medium were used. When transformed clones were selected, purified by recloning, and examined at both temperatures, only cell lines induced by A mutants lost the transformed phenotype at the higher temperature. Thus, A function is required for maintenance of the transformed phenotype in Chinese hamster lung cells. A function is known to be required for the initiation of viral DNA synthesis in permissive cells. Therefore, transformation may be a consequence of the introduction into a cell of the capacity for aberrant initiation of DNA replication.

Adsorption↗
PubMed1975

Surgery and postoperative radiotherapy in the treatment of soft tissue sarcomas in adults.

A retrospective review of 100 selected patients with soft tissue sarcomas treated by conservative excision and postoperative radiation therapy shows the following: 1. In extremity lesions, a functional limb can be preserved. The 5 year survival rate free of disease is 62 per cent (23/37). 2. The control rate of the soft tissue sarcomas is related to the anatomic site of origin rather than histologic type of the tumor except rhabdomyosarcomas. In lesions of the extremities, the control rate is 82 per cent (51/62). 3. The first manifestation of spread is usually distant metastasis rather than regional lymph node metastasis. 4. The complications can be minimized if sufficient attention is given to the placement of the surgical scar and the radiotherapeutic technique.

Adolescent↗
PubMed1975

The management of soft tissue sarcomas in adults: surgery and postoperative radiotherapy.

Traditionally soft tissue sarcomas have been managed by surgery, because they were considered radioresistant. Experience has shown that the local recurrence rate after a simple excision is 90 per cent and 30 per cent after radical surgical procedures. The treatment of soft tissue sarcomas by radical ratiation therapy alone is also unrewarding-the local recurrence rate being 66 per cent. In order to preserve a functional limb, a selected group of patients was treated using a conservative surgical excision of the gross tumor (usually a simple "shelling out"), and immediate postoperative radiation therapy. The rationale for removing all gross tumor by conservative surgical excision is that the remaining subclinical disease can be destroyed with moderate doses of postoperative irradiation. In 70 patients with soft tissue sarcomas of the extremities, all local failures occurred in tumors of the fleshy parts with a recurrence rate of 17.2 per cent, independent of the histological type. In spite of generous radiation fields, 4 of the 12 local recurrences were outside of the irradiated volume, some more than 5 cm from the margin of the field. This documents the tendency of soft tissue sarcomas to spread along the fascial planes for a great distance. To avoid complications only part of the entire circumference of an extremity must be irradiated since a severe constricting fibrosis may result with varying degrees of edema distal to the irradiated volume when all of most of the circumference is irradiated. This retrospective review of patients treated for extremity lesions by conservative excision and postoperative radiotherapy shows that a functionnal limb can be preserved in 80 per cent of the patients.

Cobalt Radioisotopes↗
PubMed1974

Complementation analysis of simian virus 40 mutants.

Seventy six new temperature-sensitive mutants of simian virus 40 have been isolated. A simple modification of the standard plaquing technique permits complementation analyses to be performed readily. By using this technique the new mutants have been divided into four complementation groups.

Animals↗
PubMed1974

Viral DNA synthesis in cells infected by temperature-sensitive mutants of simian virus 40.

Temperature-sensitive mutants of simian virus 40 (SV40) have been classified as those that are blocked prior to viral DNA synthesis at the restrictive temperature, "early" mutants, and those harboring a defect later in the replication cycle, "late" mutants. Mutants of the A and D complementation groups are early, those of the B, C, and BC groups are late. Our results confirm earlier reports that A mutants are defective in a function required for the initiation of each round of viral DNA synthesis. D mutants, on the other hand, continue viral DNA replication at the restrictive temperature after preincubation at the permissive temperature. The length of time required for D function to be expressed at the permissive temperature-after which infection proceeds unabated on shifting of the cultures to the restrictive temperature-is 10 to 20 h. The viral DNA synthesized in D mutants under these conditions progresses in normal fashion through replicative intermediate molecules to mature component I and II DNA molecules.

Animals↗