Gastric carcinoma cells with endocrine differentiation show no evidence of proliferation.

The proliferative activity of gastric cancer cells with endocrine features was evaluated in five cases by means of a double-immunostaining procedure. The endocrine cells were recognized by a monoclonal antibody to chromogranin A (CGA) and the proliferative activity by a monoclonal antibody to proliferating cell nuclear antigen (PCNA). With the use of two different chromogens it was easy to determine whether CGA was located in the cytoplasm and whether PCNA was located in the nucleus of the same section. The CGA-positive endocrine cells of the normal gastric antral mucosa could be readily distinguished from the PCNA-positive cells scattered in the mucosal neck zones. Over 1,000 CGA-positive cancer cells were counted per case. A few cells (average, less than 1.0%) exhibited faint nuclear staining with anti-PCNA; in no instance was unequivocal PCNA reactivity demonstrable in the gastric cancer cells with endocrine differentiation. By contrast, the PCNA reaction was positive in one fourth to one third of the other cancer cells. These observations suggest that gastric cancer cells with endocrine features are differentiated and do not participate in the cell cycle.     

Local blood flow changes in malignant brain tumours under induced hypertension

Summary Changes in tumour blood flow under an induced hypertensive state were examined in malignant brain tumours to know if the precondition for the effectiveness of induced hypertensive chemotherapy — relative increase in tumour blood flow — are fulfilled. Tumour blood flow was measured under both a resting and an induced hypertensive state in 12 patients with various malignant brain tumours (6 gliomas, 6 metastatic brain tumours) using xenon-enhanced computed tomography. The blood pressure was elevated 40% above the systemic blood pressure of the resting state by the infusion of angiotensin II. Tumour blood flow increased 30% on average above the normal brain tissue blood flow after the induction of an induced hypertensive state (p < 0.05). The tumour blood flow increased in 11 cases of malignant tumours, but decreased in one case with massive brain oedema after induced hypertension. The increase in blood flow was higher in hypervascular tumours and less in hypovascular tumours. Therefore, induced hypertensive chemotherapy probably will be more effective in hypervascular malignant brain tumours with small mass effects.     

Assay of flow cytometry for the effect of cepharanthine on resistance to doxorubicin]

The biochemical activity of cepharanthine and the possible mechanism by which it reverses the resistance to doxorubicin in P388 leukemia cells were examined in vitro. The microfluorometric analysis of the cellular level of doxorubicin in drug-resistant cells showed that cepharanthine markedly enhanced the sensitivity of doxorubicin against resistant cells in the cellular level. Cepharanthine also enhanced the inhibitory effect of doxorubicin on the incorporation of thymidine into DNA in resistant cells. The analysis of DNA histogram obtained by flow cytometry showed that doxorubicin exerted its growth-inhibitory effect by blocking the cell cycle at the G2 phase in P388 cells. At higher concentrations, doxorubicin prolonged the S phase and inhibited cell cycle progression to the G2/M phase in cells. The treatment with cepharanthine potentiated these blocking effects induced by doxorubicin in cells. It seems that the modifications of the biological effect of doxorubicin by cepharanthine are due to the change of their ability to induce DNA damage in cells.     

Moment analysis of drug disposition in kidney. II: Urine pH-dependent tubular secretion of tetraethylammonium in the isolated perfused rat kidney

Effects of urine pH on the renal tubular secretion of an organic cation (tetraethylammonium, TEA) and an organic anion (p-aminohippurate, PAH) were investigated using the isolated erythrocyte-perfused rat kidney. The method was based on a multiple indicator dilution experiment and noncompartmental moment analysis. Treatment with sodium bicarbonate and sodium dihydrogen phosphate increased and decreased urine pH, respectively, but affected neither the condition of the perfused kidney nor the renal handling of albumin and inulin. In TEA studies, the increase of urine pH prolonged the mean residence time in renal epithelial cells (T cell) and reduced the apparent secretion intrinsic clearance, but did not influence the volume of distribution in the kidney (Vd drug). The decrease of urine pH did not affect these kinetic parameters. By contrast, PAH secretion was constant against the change of urine pH. Since any change in the basolateral membrane transport is reflected in Vd drug, the net transport from blood to cells can be regarded as similar under these treatments. On the other hand, the prolonged T cell of TEA with the increased urine pH suggested a slow transport from cells to lumen across the brush-border membranes. The present results coincide with the hypothetical mechanism that organic cations are secreted via an active transport system, coupled to the countertransport of H+ into cells. In conclusion, the present method is useful to separately evaluate the transmembrane transport across both sides of the renal epithelial cells in a morphologically intact kidney.     

Enhanced clearance of lactic dehydrogenase-5 in severe combined immunodeficiency (SCID) mice: effect of lactic dehydrogenase virus on enzyme clearance.

The lactic dehydrogenase (LDH) level in plasma and the clearance of LDH in C.B-17 scid (severe combined immunodeficiency; SCID) mice were compared with those in C.B-17 or BALB/cCrSlc mice with or without lactic dehydrogenase virus (LDV) infection. The resting enzyme level in SCID mice showed little difference from that in C.B-17 or BALB/cCrSlc mice. The degree of increased plasma LDH level in SCID mice was lower than that in C.B-17 and BALB/cCrSlc mice after LDV infection. To assess the mechanisms of decrease in LDH elevation in SCID mice infected with LDV, virus replication was compared in SCID and BALB/cCrSlc mice. The infectivity titre of plasma in SCID mice was higher (more than 10 times) than that in BALB/cCrSlc mice. Moreover, the percentage of virus antigen positive Kupffer cells was higher in SCID mice than that in BALB/cCrSlc mice. The level of endogenous LDH release as a result of carbon tetrachloride treatment was similar in the SCID and BALB/cCrSlc mice. The clearance rate of endogenous LDH was greater in SCID mice than in BALB/cCrSlc mice with or without LDV infection. The rate of clearance of intravenously injected porcine LDH-5, but not porcine LDH-1, was enhanced in SCID mice as compared with that in BALB/cCrSlc mice. Furthermore, carbon clearance was higher in SCID mice than that in BALB/cCrSlc mice. These results suggest that the smaller increase of plasma LDH after infection might be due, at least in part, to the enhanced LDH-5 clearance function by macrophages in SCID mice.     

Alterations of nuclear pores in preneoplastic and neoplastic rat liver lesions induced by 2-acetylaminofluorene

The nuclear pore density and area were measured on freeze-fracturednuclei of ACI/N rat liver altered foci, adenomas and carcinomasinduced by 2-acetylaminofluorene, and compared with those ofnormal hepatocytes. The pore density of nuclei from these preneoplasticand neoplastic lesions was significantly higher than that ofhepatocytes, but there was no difference between lesions. Thearea of nuclear pores of the focus cells did not differ fromnormal hepatocytes, whereas the areas of pores of adenoma andcarcinoma cells were increased. Moreover, the nuclear pore areaof carcinomas was significantly greater than that of adenomas.These results suggest that some changes may occur in nuclearpores in the progress of tumorigenesis.     

Diuretic and hypotensive actions of torasemide in hypertensive models of rat

The diuretic and the antihypertensive actions of torasemide were examined in renal and genetic hypertensive rats and compared to the effects of furosemide. Oral administration of torasemide (1 and 3 mg/kg) elicited a dose-dependent increase in the excretion of urine and electrolytes and elevated the urinary Na/K ratio in both renal and genetic hypertensive rats. Torasemide and furosemide had a similar maximum diuretic effect in the normotensive Wistar rat and the spontaneously hypertensive rat (SHR). However, the diuretic activity of furosemide was weaker in the renal hypertensive rat (RHR). Torasemide showed approximately 30 times greater diuretic potency than furosemide. Torasemide and furosemide demonstrated hypotensive action in hypertensive rat models, but not in the normotensive Wistar rat. Especially in the RHR, torasemide exhibited a more potent hypotensive action than furosemide. These results show that the diuretic and antihypertensive activities of torasemide are effective in various rat models of hypertension, while the diuretic activity of furosemide is weak in certain hypertensive rat models. © 1992 Wiley-Liss, Inc.     

Intestinal active absorption of sugar-conjugated compounds by glucose transport system: implication of improvement of poorly absorbable drugs.

The intestinal absorption of glucose- and galactose-conjugated compounds was studied in the everted sac of the rat small intestine. The absorption clearance of p-nitrophenyl beta-D-glucopyranoside (p-NPglc) at 250 microM in the mucosal side (4.45 +/- 0.34 microL/min/cm, mean +/- SE, N = 4), calculated by dividing the absorption rate by the drug concentration, was significantly decreased (0.476 +/- 0.036 microL/min/cm) in the presence of 1 mM phloridzin, an inhibitor of glucose transport, and in the absence of Na+, a cosubstrate of the glucose transport carrier (0.424 +/- 0.018 microL/min/cm). The absorption clearance of p-NPglc was decreased as its concentration increased. In the same experiment, the absorption clearance of p-nitrophenyl beta-D-galactopyranoside (1.99 +/- 0.23 microL/min/cm) was also significantly decreased in the presence of phloridzin and in the absence of Na+. However, the absorption clearance of p-nitrophenyl beta-D-mannopyranoside (0.811 +/- 0.013 microL/min/cm) was low and not significantly decreased in the presence of phloridzin (P greater than 0.1). Furthermore, the absorption clearance of beta-naphthyl beta-D-glucopyranoside and beta-naphthyl beta-D-galactopyranoside was also significantly decreased in the presence of phloridzin (P less than 0.001). These results indicated that the glucose and galactose moieties provided these compounds with a new route by way of the glucose transport carrier for intestinal absorption.     

Reduction of osteoclasts in a critical embryonic period is essential for inhibition of mouse tooth eruption.

Alveolar bone resorption by osteoclasts is essential for tooth eruption. Osteoclast-deficient Csfm(op) homozygous (op/op) mice, which lack functional macrophage colony-stimulating factor (M-CSF), suffer from osteopetrosis and completely lack tooth eruption. Although osteoclasts appear, and osteopetrosis is cured with age in op/op mice, tooth eruption is never seen. This fact suggests that there is a critical period when osteoclasts are required for tooth eruption. In this study, to detect the critical period, we administered an antagonistic antibody directed against c-Fms, a receptor for M-CSF, to inbred C57BL/6 mice for various periods. Administration of this antibody decreased tartrate-resistant acid phosphatase-positive (TRAP) osteoclasts, and incisor eruption was completely inhibited by continual administration of this antibody from embryonic day 15.5 (E15.5) until postnatal day 12.5 (D12.5). A 1-day delay of this administration abolished the inhibition of incisor eruption. The number of TRAP-positive osteoclasts was significantly reduced between E16.5 and E18.5 in the mice treated with antibody from E15.5 compared with those treated from E16.5. These results indicate that this period, during which the number of osteoclasts decreases significantly, is critical for inhibiting incisor eruption in C57BL/6 mice.     

Vascularized rib strut technique for repair of pectus excavatum.

A vascularized rib strut based on the anterior intercostal branch of the internal mammary artery was applied to provide rigid internal fixation of the chest wall after correction of pectus excavatum. The procedure is simple and has substantial advantages when compared with techniques using metallic struts or nonvascularized free rib grafts.