Cross-reacting tumor-associated antigen (s) among chemically induced rat colon carcinomas.
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Biomedical subjects
Publications and source records attributed to G Steele.
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Hepatic stimulator substance is a liver growth stimulator derived from the hepatocyte cytosol of weanling or regenerating adult rat livers. The present paper reports the almost 9,000-fold purification of hepatic stimulator substance with an approximately 100,000-fold increase in specific growth stimulator activity. Purification steps included heating at 95 degrees C for 15 min, 40% cold ethanol precipitation, passage over Procion Red HE3B, DEAE cellulose and Sephadex G75 columns and gel filtration and reverse-phase fast protein liquid chromatography techniques. As little as 27 ng per ml of the purest material produced a 2-fold stimulation in the standard HTC cell activity assay. Further studies indicate that hepatic stimulator substance is a highly negatively charged protein and that disulfide bonds or a complex tertiary structure are not essential to its activity. Hepatic stimulator substance is stable over a wide range of pH's and temperatures. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis with silver stain revealed 1 major band at 12,400 daltons and 1 minor band at 17,500 daltons.
Second-look surgery for recurrent colorectal carcinoma has been advocated for over four decades. Routine follow-up procedures gave way to clinically directed or carcinoembryonic (CEA)-directed procedures in the mid-1970's. In this paper, we review the results of second-look surgery for recurrent colorectal carcinoma and ask the question, "Is it worthwhile?" Excluding surgery for symptomatic patients, we conclude that second-look surgery should only be performed for recurrent colorectal carcinoma with the intent of rendering the patient disease-free. Without effective systemic therapy, "palliative" or "debulking" procedures probably do not increase survival. The most likely candidates for such a curative approach with second-look surgery are those with isolated liver, pulmonary, and, less frequently, regional recurrences.
Multimodality therapy has not reproducibly improved the survival of patients with gastric adenocarcinoma. This is largely because the staging of disease has been imprecise and because the current regimens have only limited efficacy against advanced disease. Until staging is improved and active regimens are found, it will be difficult to identify synergism between surgery and other treatment modalities.
An emphasis on careful surgical staging of adenocarcinoma of the colon has improved the predictive value of tumor staging systems. As a result of improved staging and carefully conducted randomized clinical trials, adjuvant therapy of locally advanced colon cancer, based on 5-fluorouracil chemotherapy, has been proven to substantially reduce recurrence rates and significantly increase overall survival for selected patients. Improved treatments and schedules are currently being studied in randomized trials and may increase the efficacy of this adjuvant therapy. Radiation therapy has not as yet been integrated into the adjuvant treatment of colon carcinoma. The application of a combined approach of surgery and chemotherapy in selected patients with liver metastases may also improve cure rates and long-term survival. The developing understanding of molecular determinants for the biological behavior of these cancers will increase the opportunities to identify, on the one hand, those patients who will benefit from specific therapies, and, on the other hand, new therapeutic strategies and treatments.
The goals of the conservative management of adenocarcinoma of the distal rectum are to preserve rectal sphincter function and achieve excellent local tumor control. Multimodality therapy for more advanced disease suggests that these goals will be met by conservative surgery combined with radiation therapy and chemotherapy. Over 100 patients with T0-3 N0-1 lesions have been treated in prospective single institution trials with either local excision or anterior resection with coloanal anastomosis, usually combined with chemotherapy and radiotherapy. The typical criteria for local excision have been for lesions to be 4.0 cm or less, mobile, and not poorly differentiated or mucinous. Patients with larger or more advanced lesions may undergo anterior resection with coloanal anastomosis. Following resection, radiotherapy is delivered to the pelvis and tumor bed often with concomitant chemotherapy. The overall rate of local failure in the trials in which local excision is performed with postoperative chemoradiotherapy is 3% for T1 lesions, 5% for T2 lesions, and 30% for T3 lesions with a median follow-up of at least 25 months. Local failure in patients with a coloanal anastomosis is 9% overall. Salvage was successful in about half of the patients who failed locally. Importantly, nearly all patients remained continent. These institutional studies show that sphincter preservation can be used in patients who are objectively selected for this procedure. However, before this multimodality approach may be considered standard therapy the rate of local control must be confirmed in a large, Phase II, multicenter, prospective trial such as that now underway in many of the cooperative groups.
The treatment of locally advanced rectal carcinoma is one of the more complicated problems in the management of colorectal carcinoma. More than any other site successful treatment requires a multimodality approach as surgery alone is frequently insufficient to completely eradicate all disease. This review focuses primarily on the management of patients who present without prior treatment and discusses the role of preoperative radiation therapy as well as intraoperative radiation therapy. Although much less gratifying, patients who present after failing previous therapy may also benefit from an aggressive multimodality approach.
The application of laparoscopy to the staging of solid abdominal tumors is reviewed. The current evidence support the use of laparoscopy particularly in hepatic tumors. There is evidence that the hospital length of stay for a patient with a nonresectable hepatic tumor can be reduced from 5.6 +/- 0.4 days with a laparotomy to 1.5 +/- 0.3 days with a laparoscopy. Where the palliative and bypass issues are not limiting, cases of pancreatic and gastric carcinoma also appear to benefit in having a staging laparoscopy before a formal laparotomy for resection. Current instrumentation does produce limits, but with future prospects of laparoscopic ultrasound, and tumor staining, staging laparoscopy will become an important diagnostic tool in surgical oncology.
Recent proposals for health care reform center on restructuring the physician workforce in favor of more "generalists." These plans are based on several assumptions that have been neither clearly argued nor proved. Despite this, each of the plans enunciated thus far dictate that primary care physicians comprise at least 50% of the nation's physician workforce. Such a mandate has enormous repercussions for medical education. This paper takes issue with several assumptions underlying these reform initiatives, particularly the assumption that primary care does not include surgery. Because of the primary nature of surgical care, the prevalence of surgical diseases, the projected shortage of physicians entering general surgery, and the fact that surgical care is most effectively and efficiently provided by general surgeons, general surgery should not be handicapped as it would under present reform proposals. We recommend that the assumptions underlying plans to restructure the nation's physician workforce be tested, and that any reform enacted be based on rational criteria linked to the projected prevalence of disease in the nation as well as a determination of which practitioners care for those diseases most effectively and efficiently. We further recommend that medical students' time in surgical activities be increased rather than decreased, that general surgeons increase their activity in medical school curricular development and teaching, and that surgeons become involved more actively in the graduate training of primary care physicians.
There are now excellent data that patients with stage III colon cancer or stage II and III rectal cancer live longer if they receive, respectively, systemic or regional and systemic therapy after surgery. In addition, disease-free survival, particularly freedom from the symptoms of regional recurrence, in the high risk rectal cancer patient population has been markedly improved by application of multimodality treatment approaches. Newer prospective protocol testing variations in administration of systemic therapy, addition of 5-fluorouracil modulation techniques that proved effective in advanced disease settings, and the combination of therapy attempting to decrease single treatment toxicities while maintaining an antitumor effect have been built on the initial dramatic successes of the past 20 years. This paper concisely summarizes the data that should allow a marked decrease in mortality and morbidity if applied uniformly to patients who remain at high risk for recurrence after surgery for their colon or rectal adenocarcinomas.
The recognition of a high incidence of local failure following surgical management of adenocarcinoma of the gallbladder has led to the use of adjuvant radiation therapy. In order to deliver higher doses to the gallbladder bed, intraoperative radiation therapy (IORT) has been used both with and without external beam radiation. The experience to date is reviewed. Ten patients have been treated, all of whom had either gross residual or unresected disease. The median survival for the group was approximately 1 year. There were no long-term survivors. The IORT did not contribute to the overall morbidity. Because of the limited number of patients and the advanced nature of the disease, the role of IORT in the management of gallbladder carcinoma has yet to be determined. The utility of this modality will most likely reside in the treatment of minimal residual disease at the time of cholecystectomy rather than in the palliative treatment of unresectable tumors.
Although some would argue about the value of routine follow-up of patients with colon and rectal cancer, well designed programs of testing have been shown to identify treatable recurrence at its earliest detectable stage. Treatment of these recurrences appears to be associated with improved survival. Newer applications of radiolabeled antibodies that are directed to specific or nonspecific cell surface epitopes may increase the value of serologic tumor markers. Ultimately, the application of progressively more stringent cost controls in our medical care delivery systems will demand that follow-up tests be proven of value either in a curative or palliative sense to the patient with recurrent disease.
The median survival of all patients with hepatic metastases from colorectal cancer referred to the Sidney Farber Cancer Institute during a five-year period was 12.5 months. Two major factors influenced survival. The first was extent of disease at presentation. The second was the histologic grade of the cancer. The median survival of patients presenting with the least disease, characterized by less than four liver nodules visible on liver scan (n = 38), normal liver size on physical examination (n = 60), normal liver function test results (n = 30), and normal performance status (n = 91), was between 18 and 24 months, regardless of treatment. The median survival of those few patients (n = 13) who had objective responses to a variety of treatments, most of whom also had minimal disease at presentation, was also 24 months. Patients whose tumors were poorly differentiated or who had abnormal performance status or weight loss of greater than 10 per cent at presentation survived only six months (median). Those with four or more liver nodules, hepatomegaly (greater than 16-cm vertical span on physical examination), or abnormal liver function test results, survived ten, eight, and 12 months (median), respectively. It is concluded that a significant group of patients survived longer than would have been predicted by earlier literature surveys after the diagnosis of colorectal cancer metastatic to the liver. It is suggested that future therapeutic trials, using survival as a measure of response of patients with liver metastases from colorectal cancer, must be prospectively controlled before selection factors can be differentiated from significant therapy effect.
BACKGROUND: Morbidity associated with a nonhealing perineal wound is the most common complication following proctectomy, particularly in the setting of recurrent carcinoma of the rectum and radiation therapy. Immediate reconstruction using the gracilis myocutaneous and muscle flaps significantly reduces the incidence of major infection associated with perineal wound closure. The purpose of this study was to assess the value of immediate reconstruction of the perineal wound using a gracilis flap in patients undergoing abdominoperineal resection and intraoperative radiation therapy. METHODS: This study retrospectively reviewed our experience with immediate pelvic reconstruction using gracilis muscle flaps for patients undergoing rectal extirpation and irradiation for recurrent carcinoma of the rectum. From 1990 to 1995, 16 patients underwent abdominoperineal resection (APR) or pelvic exenteration accompanied by immediate wound closure with unilateral or bilateral gracilis muscle flaps. Morbidity and mortality outcomes were compared to those of 24 patients from our institution who, between 1988 and 1992, underwent proctectomy and irradiation for recurrent rectal carcinoma with primary closure of the perineal wound. RESULTS: Major complications (i.e., major infection requiring hospitalization and/or operation) occurred in 2 (12%) of the patients with gracilis flaps versus 11 (46%) of the patients with primary closure (P = .028 by chi2 analysis for flap vs. primary closure). Minor complications (i.e., persistent sinus and subcutaneous abscess) occurred in 4 (25%) of the patients with gracilis flaps versus 5 (21%) of those with primary closure. CONCLUSION: Immediate perineal reconstruction using the gracilis myocutaneous flap following proctectomy and irradiation for recurrent rectal carcinoma significantly reduces the incidence of major infection associated with perineal wound closure.
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A pilot study was conducted to determine whether persons at high risk of exposure to three waste sites in the area of Bloomington, Indiana, have abnormally elevated serum polychlorinated biphenyl (PCB) levels. In addition, we attempted to determine which environmental pathways might have contributed most to these exposures. First, a screening questionnaire survey of 995 individuals was conducted; on the basis of these data, 114 of the persons who had the greatest potential for exposure were selected for inclusion in this pilot exposure assessment study. People near these waste sites have higher average serum PCB levels, and a greater percentage have abnormally elevated serum PCB levels, compared with previously characterized populations in the United States. However, we could not distinguish specific pathways of exposure and uptake, with the exception of persons with occupational exposures and, possibly, among persons who reportedly salvaged metal from discarded electrical equipment. Exposures in this community require further evaluation.