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Mammalian glycerophosphodiesterases (GDEs) were recently shown to be involved in multiple cellular signaling pathways. This study showed that decreased GDE5 expression results in accumulation of intracellular glycerophosphocholine (GPC), showing that GDE5 is actively involved in GPC/choline metabolism in 3T3-L1 adipocytes. Using 3T3-L1 adipocytes, we further studied the biological significance of GPC/choline metabolism during adipocyte differentiation. Inhibition of GDE5 suppressed the formation of lipid droplets, which is accompanied by the decreased expression of adipocyte differentiation markers. We further showed that the decreased GDE5 expression suppressed mitotic clonal expansion (MCE) of preadipocytes. Decreased expression of CTP: phosphocholine cytidylyltransferase (CCTβ), a rate-limiting enzyme for phosphatidylcholine (PC) synthesis, is similarly able to inhibit MCE and PC synthesis; however, the decreased GDE5 expression resulted in accumulation of intracellular GPC but did not affect PC synthesis. Furthermore, we showed that mRNAs of proteoglycans and transporters for organic osmolytes are significantly upregulated and that intracellular amino acids and urea levels are altered in response to GDE5 inhibition. Finally, we showed that reduction of GDE5 expression increased lactate dehydrogenase release from preadipocytes. These observations indicate that decreased GDE5 expression can suppress adipocyte differentiation not through the PC pathway but possibly by intracellular GPC accumulation. These results provide insight into the roles of mammalian GDEs and their dependence upon osmotic regulation by altering intracellular GPC levels.

application/pdf, Objective We aimed to clarify the optimal timing for the fluorescence imaging of brain tumor tissue differentiated from brain edema after the administration of photosensitizers. Methods We have performed an in vivo study of the kinetics of 5-aminolevulinic acid (5-ALA) in comparison with talaporfin sodium using the rat brain tumor model and rat vasogenic edema model produced by cold injury. The in vivo kinetics of 5-ALA and talaporfin sodium in brain tumor model and the vasogenic edema model was determined by a fluorescence macroscope and a microplate reader. Results The in vivo kinetic study of 5-ALA showed mild fluorescence intensity of protoporphyrin IX (PpIX) in brain tumor differentiated from vasogenic edema. The mean lesion-to-normal-brain ratio (L/N ratio) in the group of brain tumor model 2 h after the administration of 5-ALA was 7.78 ± 4.61, which was significantly higher (P < 0.01) than that of the vasogenic edema 2 h after the administration of 5-ALA (2.75 ± 1.12). In vivo kinetic study of talaporfin sodium showed high fluorescence intensity and retention in brain tumor differentiated from vasogenic edema. The mean L/N ratio of the fluorescence intensity in the group of brain tumor model 12 h after the administration of talaporfin sodium was 23.1 ± 11.9, which was significantly higher (P < 0.01) than that of the vasogenic edema 12 h after the administration (8.93 ± 8.03). Conclusions The optimization of fluorescence imaging of brain tumors differentiated from brain edema is possible in the case of 5-ALA within 6 h, and also possible in the case of talaporfin sodium beyond 12 h.

A simple new method for making a rat post-angioplasty stenosis model was developed using a single-lumen compliant balloon catheter/guidewire system and no special diet. This technique was applied to 10 9-week-old Wistar rats fed a normal diet. The catheter/guidewire system was inserted from the external carotid artery and advanced retrogradely into the common carotid artery. The balloon was inflated six times with rotation through 60°. After angioplasty, the external carotid artery was ligated. Homogeneous stenoses due to intimal hyperplasia were demonstrated in cross sections of all cases. This simple and gentle method allows an easily reproducible post-angioplasty stenosis model.

We used a two-color analysis system to assess the porphyrin uptake and DNA content in four established cell lines of glioma employing flow cytometry (FCM). The FCM study revealed porphyrin uptake in all cells, regardless of the phase of the cell cycle they were in. However, those in the G0/G1 phase showed moderate uptake of porphyrin and those in the G2/M phase showed a higher uptake. These results indicated the advantage of using porphyrin as the carrier of tumor targeting agents as a therapeutic strategy for malignant tumors.

BPA used in BNCT has a similar structure to some essential amino acids and is transported into tumor cells by amino acid transport systems. Previous study groups have tried various techniques of loading BPA to increase intracellular boron concentration. CHO-K1 cells demonstrate system L (LAT1) activity and are suitable for specifying the transport system of a neutral amino acid. In this study, we examined the intracellular accumulation of boron in CHO-K1 cells by amino acid transport control, which involves co-loading with L-type amino acid esters. Intracellular boron accumulation in CHO-K1 cells showed the greatest increased upon co-loading 1.0 mM BPA, with 1.0 mM l-Tyr-O-Et and incubating for 60 min. This increase is caused by activation of a system L amino acid exchanger between BPA and l-Tyr. The amino acid esters are metabolized to amino acids by intracellular hydrolytic enzymes that increase the concentrations of intracellular amino acids and stimulate exchange transportation. We expect that this amino acid transport control will be useful for enhancing intracellular boron accumulation.

A simple new method for making a rat post-angioplasty stenosis model was developed using a single-lumen compliant balloon catheter/guidewire system and no special diet. This technique was applied to 10 9-week-old Wistar rats fed a normal diet. The catheter/guidewire system was inserted from the external carotid artery and advanced retrogradely into the common carotid artery. The balloon was inflated six times with rotation through 60 degrees . After angioplasty, the external carotid artery was ligated. Homogeneous stenoses due to intimal hyperplasia were demonstrated in cross sections of all cases. This simple and gentle method allows an easily reproducible post-angioplasty stenosis model.

application/pdf, We examined the simultaneous uptake of porphyrin and (LDL) by four established cell lines of glioma and normal ®broblasts using ¯ow cytometry (FCM). The results indicated porphyrin and LDL showed competitive conjugation with the LDL receptor. These results support the theory of the porphyrin uptake via the LDL receptor.

Transglucosylation of an α-glucosidase (I) from honeybee was investigated. The honeybee α- glucosidase catalyzed the predominant formation of α-1,4-glucosidic linkage from sucrose, phenyl α-glucoside, or maltose. The major product from sucrose was 4G-a-glucosyl-sucrose (erlose), which differs from the report by Huber and Thompson that 3F-a-glucosyl-sucrose (melezitose) is mainly synthesized from sucrose by the transglucosylation of the same α-glucosidase: Biochemistry, 12, m 4011 (1973). Melezitose was not detected as the transglucosylation product of this enzyme.