Response suppression as a function of intensity and duration of a punishment.
Explore the source record for details and available documents.
Animals↗
Biomedical subjects
R D Beauchamp
Publications and source records attributed to R D Beauchamp.
Nonoperative management of primary colorectal cancer in patients with stage IV disease.
BACKGROUND: Traditional teaching maintains that patients with primary colorectal adenocarcinoma require timely resection to prevent bleeding, perforation, or obstruction. The true benefits of primary tumor resection remain undocumented for patients presenting with metastatic disease, however. We postulated that resection of primary colorectal tumors could be avoided safely in a select population of asymptomatic colorectal cancer patients presenting with incurable stage IV disease. METHODS: A retrospective review of the Vanderbilt University Hospital tumor registry was performed for the years 1985 to 1997. During this period, 955 patients presented for management of primary colorectal cancer. From this group, all patients with stage IV disease at the time of diagnosis were identified. Patients who initially underwent resection of their primary lesion were included in the resection group; those who underwent initial nonoperative primary tumor management were included in the nonresection group. Data were obtained regarding age, extent of disease, nonsurgical therapy, tumor-specific complications, and palliative surgical procedures. Surgery-free survival and overall survival were analyzed using the Kaplan-Meier method. For patients with liver metastases, hepatic tumor burden was defined as either H1 (<25% parenchymal replacement), H2 (25% to 50%), or H3 (>50%) disease. RESULTS: Sixty-six patients were included in the resection group, and 23 patients with intact asymptomatic primary colorectal lesions were included in the nonresection group. Among patients with hepatic metastases, most of the patients in both groups had H1 disease. Ten patients in the resection group and 3 patients in the nonresection group presented with exclusively extrahepatic metastases. In the nonresection group, primary therapy included chemotherapy in 13 patients, external beam radiation therapy in 1 patient, and combination chemoradiation in 9 patients. The median survival in the nonresection group was 16.6 months. The 2-year actuarial survival was 18%, and the surgery-free survival was 91.3%. Only 2 of 23 patients (8.7%) managed without resection eventually developed obstruction at the primary tumor site requiring emergent diversion. There were no episodes of tumor-related hemorrhage or perforation. For the resection group, the operative morbidity was 30.3%, and the perioperative mortality rate was 4.6%. The median survival in the resection group was 14.5 months (P = 0.59, log-rank test vs. nonresection group). CONCLUSIONS: Selected patients with asymptomatic primary colorectal tumors who present with incurable metastatic disease may safely avoid resection of their primary lesions, with an anticipated low rate of hemorrhage, perforation, or obstruction before death from systemic disease. No survival advantage is gained by resection of an asymptomatic primary lesion in the setting of incurable stage IV colorectal cancer.
Adenocarcinoma↗
Posttranscriptional regulation of cyclooxygenase-2 in rat intestinal epithelial cells.
Modulation of cyclooxygenase-2 (COX-2) mRNA stability plays an important role in the regulation of its expression by oncogenic Ras. Here, we evaluate COX-2 mRNA stability in response to treatment with two known endogenous promoters of gastrointestinal cancer, the bile acid (chenodeoxycholate; CD) and ceramide. Treatment with CD and ceramide resulted in a 10-fold increase in the level of COX-2 protein and a four-fold lengthening of the half-life of COX-2 mRNA. COX-2 mRNA stability was assessed by Northern blot analysis and by evaluating the AU-rich element located in the COX-2 3'-UTR. A known inhibitor of mitogen-activated protein (MAP)/extracellular signal-regulated kinase (ERK) kinase (MEK), PD98059, reversed the effects of CD or ceramide to stabilize COX-2 mRNA. Overexpression of a dominant-negative ERK-1 or ERK-2 protein also led to destabilization of COX-2 mRNA. Treatment with a p38 MAPK inhibitor, PD169316, or transfection with a dominant-negative p38 MAPK construct reversed the effect of CD or ceramide to stabilize COX-2 mRNA. Expression of a dominant-negative c-Jun N-terminal kinase (JNK) had no effect on COX-2 mRNA stability in cells treated with CD or ceramide. We conclude that posttranscriptional mechanisms play an important role in the regulation of COX-2 expression during carcinogenesis.
Animals↗
Fracture of the lumbar vertebral apophysis.
Three cases of vertebral apophyseal fracture and displacement presenting with back pain are reported. Literature review revealed 11 other such cases, and these are compared. Computed tomography scan was found to be an excellent tool to confirm this diagnosis.
Accidents, Home↗
Osteoblastoma in the very young: report of two cases.
Two cases of tumors caused by osteoblastoma in children less than 3 years old are presented. This report points out that although most osteoblastomas appear in patients less than 30 years old, it is uncommon for the lesion to present in the very young. The authors note that osteoblastoma should be considered in the differential diagnosis of a lytic lesion because patients may be too young to communicate their complaints.
Child, Preschool↗
Effect of a cholecystokinin antagonist, proglumide, on cholecystokinin-8-induced gallbladder contraction in conscious dogs.
The objective of this study was to characterize the effect of proglumide, a cholecystokinin (CCK) antagonist, on gallbladder contraction stimulated by CCK in conscious dogs. The gallbladder contraction was monitored by a strain-gauge force transducer that was chronically sutured onto the serosal surface of the gallbladder. The results of this study show that proglumide, given as an intravenous bolus (2.5, 5, 10, 20, and 40 mg/kg) or as a continuous intravenous infusion (150 or 300 mg/kg/h, 10 min), can block the stimulatory action of CCK in a dose-related manner. Bolus administration of proglumide resulted in a transient inhibition, whereas continuous infusion of proglumide resulted in a prolonged antagonism of CCK-stimulated gallbladder contraction. Review of the data leads to the conclusion that the antagonistic action of intravenously administered proglumide on CCK-stimulated gallbladder contraction may be characterized as rapid and reversible.
Animals↗
Soft tissue anatomy of proximal femoral focal deficiency.
The soft tissue anatomy of Aitken types A, B, C, and D proximal femoral focal deficiency (PFFD) was examined by magnetic resonance imaging (MRI). A characteristic pattern of soft tissue abnormalities is described. All muscles were present, but most were smaller than their normal counterparts. The exception was the obturator externus muscle, which was elongated and remained muscular almost up to its insertion. In type A PFFD, it is straight; in types B, C, and D PFFD, it is L-shaped. The sartorius is hypertrophied.
Adolescent↗
Supracondylar osteotomy of the humerus for correction of cubitus varus.
Reports of corrective procedures for cubitus varus (gunstock deformity) have emphasized the frequency of loss of position and significant complication. Modifications that have been made to the standard supracondylar osteotomy protocol include correction of the angular deformity only, without correction of rotation; an incomplete wedge osteotomy leaving the medial cortex intact by hinging the osteotomy shut on the intact cortex; and immobilization of the elbow in full extension with the forearm supinated. In a review of 16 patients following this protocol, 11 patients had excellent results, three had good results, and two had unsatisfactory results.
Bone Nails↗
Extraarticular subtalar arthrodesis: the dowel method.
The technique and results of extraarticular subtalar arthrodesis using the dowel method during the 10-year period between 1976 and 1986 were reviewed retrospectively. Fifty feet in 30 children underwent extraarticular subtalar arthrodesis for valgus deformity for diagnoses including meningomyelocele, idiopathic flatfoot, and cerebral palsy. The aims of the procedure were to correct the deformity, obtain a solid arthrodesis, and improve ambulation by reducing bracing requirements and eliminating pain. Results were excellent in 28 cases (56%), satisfactory in 15 (30%), and unsatisfactory in seven (14%). Intraoperative positioning error and simultaneous perineal tendon lengthening in children with cerebral palsy were the major sources of unsatisfactory results.
Adolescent↗
Management of pulseless pink hand in pediatric supracondylar fractures of humerus.
Thirteen (3.2%) of 410 patients seen in British Columbia's Children's Hospital in Vancouver from January 1984 to September 1992 with supracondylar fractures did so with an absence of a radial pulse in an otherwise well perfused hand. A combination of segmental pressure monitoring, color-flow duplex scanning, and magnetic resonance angiography (MRA) appears to be a valid, noninvasive, and safe technique in evaluating patency of the brachial artery and collateral circulation across the elbow. Based on this study, early revascularization of a pulseless otherwise well-perfused hand in children with type 3 supracondylar fractures, although technically feasible and safe, has a high rate of asymptomatic reocclusion and residual stenoses of the brachial artery. Therefore a period of close observation with frequent neurovascular checks should be completed before more invasive correction of this problem is contemplated.
Adolescent↗
A survey of the progress and direction of research at the School of Optometry, University of Waterloo.
Explore the source record for details and available documents.
Humans↗