Effect of light/dark cycle alteration on morphine-induced conditioned place preference

The influence of acute and chronic light/dark cycle alteration on morphine-induced conditioned place preference was evaluated in mice. In chronic experiments, morphine (1-10 and 2.5-10 mg/kg) induced conditioned place preference in animals maintained on 12/12 and 6/18 light/dark cycles, respectively. In mice maintained on 18/6 light/dark cycle, however, morphine produced conditioned place preference only by the dose of 10 mg/kg. This latter effect was abolished by chronic daily administration of melatonin (10, 20 mg/kg). Moreover, our data showed that both abrupt increase and decrease in photoperiod on the day before testing reduced the ability of morphine to produce place conditioning. A single melatonin (10 mg/kg) injection reversed the attenuating effect of a 6-h delay in the dark cycle on morphine conditioned place preference.     

Postoperative chemotherapy with cisplatin and 5-fluorouracil in cancer of the oral cavity and the oropharynx--long-term results

Adjuvant chemotherapy has not yet been proven to have a survival benefit for patients with head and neck cancer. Studies dealing with this topic have had several faults like mingling tumor localizations and treatment modalities. To re-examine the role of postoperative chemotherapy in oral cavity cancer, a single-center study was conducted with the attempt to have higher homogeneity. 122 patients with primary squamous cell carcinoma of the lip, the oral cavity and the oropharynx have been treated with 100 mg/m2 cisplatin bolus infusion and 120-h continuous infusion of 1000 mg/m2 5-fluorouracil following radical surgery; 99 patients completed all 3 cycles. The disease-free and overall survival are reported and compared to a control group of 161 patients with cancer of the lip, the oral cavity and oropharynx treated only with surgery, and a treatment-dependent prognostic index. After a median follow-up of 79 months (range 5-18 years), the current 5-year overall survival of the chemotherapy group was 67% and the 5-year disease-free survival was 57% while the respective data for the control group are 46% and 40%. This difference is statistically significant. The comparison with the prognostic index confirmed this result. The chemotherapy group suffered from fewer local and more neck relapses and had a much longer relapse latency (29 months versus 8 months). The toxicity of the chemotherapy regimen was tolerable. In a homogeneous population with resectable oral cavity and oropharyngeal cancer, postoperative adjuvant chemotherapy with cisplatin and 5-fluorouracil resulted in a high overall survival rate which was significantly better than in a comparable population treated only with surgery and better than the survival expectation calculated with the help of a prognostic index. A prospective randomized study of postoperative chemotherapy versus control, exclusively in patients with oral cancer, is warranted.     

Genomic organization of the canine p53 gene and its mutational status in canine mammary neoplasia

To determine whether canine malignancies share common genetic lesions with their human counterparts, and are thus potentially interesting model systems in which to pose questions regarding tumor etiology and progression, we have elucidated the entire exon/intron structure of the canine p53 gene. A search for p53 gene abnormalities in mammary tumor tissue was undertaken utilizing single strand conformation polymorphism analysis. Mutations were detected in exons 4, 5, 6, and 7 of the p53 gene and consisted of nonsense, splicing, and frameshift mutations. None of 11 benign tumors and 6 of 40 primary carcinomas (15%) were found to harbor subtle p53 mutations. In 14 carcinomas examined the results in primary tumors and metastases were the same. These findings implicate involvement of this gene in the genesis of some malignant canine tumors, in a fashion similar to their human counterparts.     

Ischemic colitis associated with sigmoid volvulus: new observations.

Ischemic colitis following conservative management of sigmoid volvulus is documented in four cases. Repeat barium enema studies in these patients showed characteristic "thumbprinting", transverse ridging, and mucosal ulcerations within a segment or the entire length of the sigmoid, lasting up to 7 days after nonoperative decompression. The development, extent, and severity of the ischemic changes seem to correlate with the degree of volvulus, blockage of venous and arterial circulation in the sigmoid mesocolon, and increased intraluminal pressure.     

Lymphoma of the stomach following gastric surgery for benign peptic ulcers

Adenocarcinoma of the gastric stump is a well-known complication of gastroduodenal surgery for benign lesions. However, we report 2 unusual cases wherein malignant lymphoma originated in the postoperative stomach. The first patient had undergone partial gastrectomy and Billroth II procedure 20 years earlier. The gastric lymphoma of the second patient manifested 39 years after vagotomy and pyloroplasty. In both instances, the tumor caused marked thickening and nodularity of the rugal folds without affecting the distensibility of the previously operated stomach. Differential diagnostic features of the observed findings and the potential carcinogenic effects of gastroduodenal surgery are reviewed.     

Prolapsing inflammatory pseudopolyp-fold complex of the oesophagogastric region

This article describes a series of 12 adult patients in whom a prominent and mobile polypoid fold of the oesophagogastric region was demonstrated radiologically. Subsequent endoscopic and histopathologic studies confirmed the presence of an inflammatory pseudopolyp at the squamocolumnar junction and contiguous with a thick gastric rugal fold. The clinical and radiographic features of this entity and the mechanisms of its formation are reviewed.     

Diagnosis and management of intraluminal duodenal diverticulum

The descending part of duodenum is the principal site for an intraluminally projecting mucosal pouch or diverticulum, but this unusual lesion may also occur elsewhere in the upper gastrointestinal tract. We report three patients in whom a large intraluminal duodenal diverticulum (IDD) was diagnosed radiographically at the ages of 15, 27, and 68 years, respectively. Fiberoptic duodenoscopy was performed in the two symptomatic cases for the removal of impacted food from IDD or dilatation of its outflow aperture. Guidelines for the diagnosis and treatment of IDD are provided based on our experience and review of the pertinent literature.