Comparison of p53 expression in proximal and distal gastric cancer: Histopathologic correlation and prognostic significance

Background: The overexpression of p53 has been found to be correlated with prognosis of some carcinomas, including gastric cancer, but no studies have reported on its relationship to the location of gastric cancer. In the present study, we compared the p53 expression of proximal and distal gastric cancer concerning histopathology and prognosis. Methods: A total of 170 tumors in the patients with proximal (80 cases) and distal (90 cases) gastric cancer were studied by immunohistochemical methods. Results: p53 immunopositivity was detected in 28.8% of all tumors. The p53-positive expression in proximal gastric cancer was higher than in distal gastric cancer (38.8% vs. 20.0%, p<0.05). A 5-year survival analysis showed that there is no significant difference between tumors that are p53 positive and p53 negative. No correlation was found between p53 expression and histopathology of gastric cancer. Conclusion: p53 nuclear staining is not useful as a prognostic indicator or as a parameter in gastric cancer.     

Time after excision and temperature alter ex vivo tissue relaxation time measurements

Previously unreported effects of tissue storage were recently observed in the authors' experimental magnetic resonance (MR) studies. To evaluate the effect of elapsed time after excision and storage temperature on tissue relaxation time measurements, tissue samples from the liver, pancreas, kidney, testis, spleen, and brain were obtained in rats. T1 and T2 were first measured within 5 minutes of excision, and between subsequent measurements, tubes were kept in a water bath at 40°C, at room temperature (28°C), or in an ice bath (4°C). Cellular and organellar integrity was assessed with electron microscopy and correlated with the MR findings. At 40°C (20-MHz spectrometer), the T1 of liver decreased from 280 msec ± 8 to 212 msec ± 10 during the first 60 minutes; the T1 of pancreas decreased from 276 msec ± 3 to 208 msec ± 2. Other tissues showed less than a 5% decrease in T1. T2 changes were smaller than T1 changes in all tissues. Electron microscopy of pancreatic acinar cells showed postmortem changes in mitochondria evolving over the first 60 minutes after death. Manganese loading experiments implicated mitochondrial manganese stores in the observed enhanced postmortem decrease in T1. This study calls into question reported relaxation time data for liver and pancreas. MR studies of excised tissues must account for time and temperature to prevent systematic experimental errors.     

Selective blood-tumor barrier disruption by leukotrienes.

The authors have previously reported that intracarotid infusion of 5 micrograms leukotriene C4 (LTC4) selectively increases blood-tumor barrier permeability in rat RG-2 tumors. In this study, rats harboring RG-2 tumors were given 15-minute intracarotid infusions of LTC4 at concentrations ranging from 0.5 microgram to 50.0 micrograms (seven rats in each dose group). Blood-tumor and blood-brain barrier permeability were determined by quantitative autoradiography using 14C aminoisobutyric acid. The transfer constant for permeability (Ki) within the tumors was increased twofold by LTC4 doses of 2.5, 5.0, and 50.0 micrograms compared to vehicle alone (90.00 +/- 21.14, 92.68 +/- 15.04, and 80.17 +/- 16.15 vs. 39.37 +/- 6.45 microliters/gm/min, respectively; mean +/- standard deviation; p less than 0.01). No significant change in Ki within the tumors was observed at the 0.5-microgram LTC4 dose. Blood-brain barrier permeability was selectively increased within the tumors. At no dose in this study did leukotrienes increase permeability within normal brain. To determine the duration of increased opening of the blood-tumor barrier by LTC4 administration, Ki was measured at 15, 30, and 60 minutes after termination of a 15-minute LTC4 infusion (seven rats at each time point). The mean Ki value was still high at 15 minutes (92.68 +/- 15.04 microliters/gm/min), but declined at 30 minutes (56.58 +/- 12.50 microliters/gm/min) and 60 minutes (55.40 +/- 8.10 microliters/gm/min) after the end of LTC4 infusion. Sulfidopeptide leukotrienes LTC4, LTD4, LTE4 and LTF4 were infused to compare their potency in opening the blood-tumor barrier. The mean leukotriene E4 was the most potent, increasing the permeability value 3 1/2-fold compared with vehicle alone (139.86 +/- 23.95 vs. 39.37 +/- 6.45 microliters/gm/min).     

Preneoplastic and neoplastic growth of xenotransplanted lung-derived human cell lines using deepithelialized rat tracheas

The human lung tumor-derived cell lines A549, Calu-1, Calu-3, HuT292, and SW900 and the transformed human bronchial epithelial cell line TBE-1, that was transfected with the v-Harvey-ras oncogene, were inoculated into deepithelialized Fisher 344 rat tracheas (5 X 10(5) cells/trachea). After the ends of the tracheas were sealed, the tracheas were transplanted into s.c. tissues of nude mice. In a parallel experiment, 1 X 10(6) cells from each of these cell lines were injected s.c. Histological examination of the tracheal transplants 2, 4, 8, 12, and 16 weeks after cell inoculation proved to be of greater usefulness than either clinical or histological observation of the s.c. injection sites. A549, Calu-1, and TBE-1 produced intratracheal neoplastic nodules as early as 2 weeks after cell inoculation. Calu-3, HuT292, and SW900 grew relatively slowly in the tracheas, and simple or stratified epithelia with slight or moderate atypia (preneoplastic lesions) were seen at 2 weeks. After the 4th week, they produced tumor nodules in the tracheal transplants, whereas no tumor cells could be seen at the s.c. injection sites. The human derivation of the cells was confirmed by in situ hybridization using human-specific DNA probes. The intratracheal inoculation and xenotransplantation of human-derived cell lines offers a time-saving alternative to the s.c. inoculation assay for tumorigenicity and is at the same time a potentially valuable approach to studying preneoplastic and neoplastic progression with human cell subpopulations.     

Prognosis for patients with carcinoma in the middle third of the stomach

In 268 of the 1,115 patients (24.0%) with gastric cancer who underwent a curative resection in our clinics, the tumor was located in the middle third of the stomach. The clinicopathological features and prognosis of these patients were divided into two groups, according to site of the tumor: anterior wall (n = 58) vs. other sites (n = 210). Clinicopathological factors did not differ between the two groups. The survival time for patients with a tumor in the anterior group was shorter than that for patients with a tumor in other areas (P < 0.05). The five-year survival rate was 79.3% for patients with an anterior tumor and 91.9% for those with a tumor at a different site. A multivariate analysis indicated lymph node metastasis, serosal invasion, and anterior wall location to be independent prognostic factors indicative of a poor prognosis when the tumor was located in the middle third of the stomach. For such patients, close follow-up is needed to detect possible recurrences. © 1993 Wiley-Liss, Inc.     

Angiotensin-converting enzyme inhibition attenuates hypercholesterolemia and glomerular injury in hyperlipidemic Imai rats.

Hyperlipidemic Imai rats spontaneously develop hypercholesterolemia, proteinuria and glomerulosclerosis. We investigated the effect of enalapril, an angiotensin-converting enzyme (ACE) inhibitor, on spontaneous hypercholesterolemia and the progressive renal injury in this rat strain. Male Imai rats (n = 7) were treated with enalapril at a dose of 50 mg/l in drinking water starting at 6 weeks of age. Body weight, blood pressure, urinary protein excretion and serum constituents were checked and compared with untreated controls (n = 5) up to 38 weeks of age. Enalapril treatment significantly reduced hypercholesterolemia (247 +/- 41 vs. 102 +/- 13 mg/dl, p < 0.01, at 38 weeks) and proteinuria (766 +/- 290 vs. 206 +/- 119 mg/kg/day, p < 0.01, at 38 weeks). The glomerulosclerosis index (SI) was significantly higher in untreated control rats than in the enalapril-treated group (227 +/- 57 vs. 27 +/- 9, p < 0.01). Although we could not clarify whether hypercholesterolemia is a primary event or secondary to the nephrotic syndrome, these results indicate that the ACE inhibitor has the property to protect remnant glomeruli from glomerulosclerosis in male Imai rats as well as in other animal models in which focal and segmental glomerulosclerosis is believed to represent a common pathologic pattern. This rat strain represents a unique model of a spontaneous proteinuria which can provide an important information on the pathogenesis of human focal and segmental glomerulosclerosis.     

Therapeutic effects of liposomal adriamycin in combination with tumor necrosis factor-alpha.

Liposomes as drug carriers in cancer chemotherapy have attracted considerable interest. To enhance the therapeutic effect of Adriamycin entrapped in liposomes (Lip-ADM) on human solid tumors, we investigated the therapeutic effects of Lip-ADM in combination with recombinant human tumor necrosis factor-alpha (rTNF-alpha), which is known to have specific effects on tumor vasculature. rTNF-alpha or saline solution was injected intravenously into nude mice bearing a human colon cancer strain, HC-1, at 1 hour before intravenous administration of Lip-ADM. The significant therapeutic effect of Lip-ADM in combination with rTNF-alpha was demonstrated by the evaluation with tumor growth curve and the actual tumor weights, in comparison with groups of mice treated with saline solution, rTNF-alpha alone, or with a Lip-ADM after saline. Levels of Adriamycin in tumor tissue in the Lip-ADM in combination with rTNF-alpha-treated group were higher than those in Lip-ADM with saline solution-treated group.