Distribution of OL-protocadherin protein in correlation with specific neural compartments and local circuits in the postnatal mouse brain

OL-protocadherin (OL-pc) is a cell adhesion molecule that belongs to the cadherin superfamily. A previous study showed that expression of OL-pc mRNA was specific to certain brain nuclei including those of the olfactory and limbic systems, thus suggesting its involvement in neural circuit formation. Here, we examined the distribution of OL-pc protein in the postnatal mouse brain by immunohistochemistry to confirm the possibility of such a role. The results showed that the protein could be mapped to many brain compartments including brain nuclei and higher subdivisions as previously observed for the expression pattern of the mRNA. Sharp boundaries of the distribution were often seen in areas such as the interpedunclar nucleus, cerebellar cortex, and inferior olive. In addition, the protein was detected in some fibers that could not be examined by the previous study using in situ hybridization. For example, prominent staining was noted in the stria medularis, stria terminalis, fasciculus retroflexus, optic tract, and inferior thalamic radiation, structures that seem to connect OL-pc-positive brain regions. These OL-pc-positive brain nuclei and fiber tracts coincide with some local circuits of functional systems such as the olfactory system, nigrostriatal projection, olivo-cerebellar projection, and visual system. These results support the possibility that OL-pc is involved in the formation of specific neural compartments and circuits in the developing brain.

Vasogenic edema and VEGF expression in a rat two-vein occlusion model

Vasogenic edema plays an important etiologic role in the pathogenesis of cerebral venous circulation disturbances (CVCDs). Since vascular endothelial growth factor (VEGF) is a major mediator in angiogenesis and vascular permeability, including induction of vasogenic edema, the present study was undertaken to investigate whether it has any relevance to CVCDs. Male Wistar rats (n = 15) were used. Two adjacent cortical veins were occluded photochemically using rose bengal dye and fiberoptic illumination, with evaluation 24 hours thereafter by magnetic resonance imaging (MRI). Each brain was removed from the skull immediately after MRI and processed for hematoxylin-eosin staining (H&E staining) of sections for histopathology and comparison with MRI data. VEGF expression as demonstrated immunohistochemically appeared to coincide with vasogenic edema, diagnosed as high intensity areas on apparent diffusion coefficient of water (ADCw) maps. On the basis of these data, we conclude that VEGF is related to formation of vasogenic edema in the acute stage of CVCD.

Selective and sustained occupancy of prostatic alpha1-adrenoceptors by oral administration of KMD-3213 and its plasma concentration in rats

This study examined the ex-vivo occupancy by KMD-3213 of alpha1-adrenoceptors in the prostate and other tissues of rats in terms of tissue selectivity and duration of occupancy in relation to plasma concentration. Oral administration of KMD-3213 (0.2-20.2 micromol kg(-1), 0.5 h) dose-dependently decreased [3H]prazosin binding sites (Bmax) in the prostate (42-74%) and submaxillary gland (54-88%) compared with the control value. In contrast, there was only a slight change in the Bmax values in the spleen and cerebral cortex of KMD-3213-treated rats. The alpha1-adrenoceptor occupancy in the prostate and submaxillary gland was increased, with plasma free concentration of KMD-3213 at 0.5 h after oral administration of KMD-3213 (0.6-20.2 micromol kg(-1)). The receptor occupancy in these tissues was much greater than that in the spleen, heart or cerebral cortex. After oral administration of KMD-3213 (6.1 micromol kg(-1)), the alpha1-adrenoceptor occupancy in the prostate and submaxillary gland occurred rapidly, in parallel with the rise in the plasma concentration of the drug, and it lasted for at least 24 h, despite a remarkable decrease in the plasma concentration. It is concluded that KMD-3213 may produce fairly selective and sustained occupancy of alpha1-adrenoceptors in the prostate, a target organ for treatment of bladder outlet obstruction in patients with benign prostatic hyperplasia.

The contribution of 2,3,5-trichlorophenyl methyl sulfone, a metabolite of 1,2,4-trichlorobenzene, to the delta-aminolevulinic acid synthetase induction by 1,2,4-trichlorobenzene in rat liver

In the present study, we investigated the contribution of methylsulfonyl metabolite derived from 1,2,4-trichlorobenzene (1,2,4-TCB) on the delta-aminolevulinic acid (ALA) synthetase induction by the parent compound in rats. The time courses of increasing of hepatic microsomal total cytochrome P450 content after a single i.p. administration of 1,2,4-TCB (1.36 mmol/kg), and 2,3,5- and 2,4,5-trichlorophenyl methyl sulfones (2,3,5- and 2,4,5-TCPSO2Mes) (50 micromol/kg each) were in parallel with those of increasing of the total heme content in liver microsomes. 1,2,4-TCB significantly increased the heme oxygenase activity, but 2,3,5- and 2,4,5-TCPSO2Mes did not. On the other hand, 1,2,4-TCB and 2,3,5-TCPSO2Me markedly enhanced the ALA synthetase activity. No change was observed in this enzyme activity after the administration of 2,4,5-TCPSO2Me. After the administration of 1,2,4-TCB to the rats treated with DL-buthionine-(S,R)-sulfoximine (BSO) and to the non-BSO-treated rats, the concentrations of both 2,3,5- and 2,4,5-TCPSO2Mes were significantly lower in liver of the BSO-treated rats than in liver of the non-BSO-treated rats. Additionally, the 1,2,4-TCB did not elevate the ALA synthetase activity in the BSO-treated rats. On the other hand, the administration of 2,3,5-TCPSO2Me to BSO-treated rats resulted in induction of ALA synthetase. The results strongly suggest that the methyl sulfone derived from 1,2,4-TCB, i.e., 2,3,5-TCPSO2Me, contributes highly to the induction of the ALA synthetase activity by the parent compound.

Metabolite of 2,2',4',5-tetrabromobiphenyl, 3-methylsulphonyl-2,2',4',5-tetrabromobiphenyl, a potent inducer of CYP2B1/2 in rat

1. 3-Methylsulphonyl- and 4-methylsulphonyl-2,2',4',5-tetrabromobiphenyls (3-MeSO(2)- and 4-MeSO(2)-TetraBrBs) were detected in the liver, lung, kidney, adipose tissue and faeces of the 2,2',4',5-tetrabromobiphenyl (TetraBrB)-dosed rat. 2. The administration of 0.05-2.0 micromol kg(-1) doses of 3-MeSO(2)-TetraBrB produced corrresponding increases in the hepatic concentration of the methyl sulphone metabolite, corresponding increases in the content of total cytochrome P450, and corresponding increases in the activities of 7-benzyloxy-, 7-ethoxy- and 7-pentoxyresorufin O-dealkylases. The inducing effects of the 3-MeSO(2)-TetraBrB (0.2 micromol kg(-1)), both on the content of total P450 and on the activities of the three alkoxyresorufin O-dealkylases, were higher than that of the parent TetraBrB (342 micromol kg(-1)). 3. The major phenobarbital (PB)-inducible forms of P450, CYP2B1, CYP2B2, CYP3A2 and CYP2C6, were substantially induced by 3-MeSO(2)-TetraBrB, but CYP1A1 and CYP1A2 were not. On the other hand, the activities of drug-metabolizing enzymes and the four PB-inducible forms of P450 were unchanged by 4-MeSO(2)-TetraBrB treatment. 4. The induction profiles of these enzymes and P450 forms in rat treated with 3-MeSO(2)-TetraBrB were similar to those treated with PB. 5. The inducing ability of 3-MeSO(2)-TetraBrB (0.5 micromol kg(-1)) both on the activities of the three alkoxyresorufin O-dealkylases and on the contents of four PB-inducible forms of P450 was roughly equal to that of PB (431 micromol kg(-1) twice at a 24-h interval) or 3-MeSO(2)-2,2',4',5-tetrachlorobiphenyl (1 micromol kg(-1)). It is noteworthy that the effects of 3-MeSO(2)-TetraBrB on the drug-metabolizing enzymes CYP2B1 and CYP2B2 were several thousand-fold higher than those of parent TetraBrB, while the effect of its isomeric 4-MeSO(2)-TetraBrB were not. 6. The extent of hepatic accumulation of the 3-MeSO(2) metabolite after the administration of TetraBrB (342 micromol kg(-1)) was almost the same as that after the administration of 3-MeSO(2)-TetraBrB (0.1-0.2 micromol kg(-1)). The relationship between the hepatic concentration of the 3-MeSO(2) metabolite and the extent of enzyme induction after the administration of TetraBrB or 3-MeSO(2)-TetraBrB suggests that 3-MeSO(2)-TetraBrB plays an important role in the induction of microsomal drug-metabolizing enzymes by TetraBrB.

High prevalence of anticardiolipin antibodies in patients with HCV-associated oral lichen planus

Hepatitis C virus (HCV) has been linked to extrahepatic manifestations such as oral lichen planus (OLP). In addition, anticardiolipin antibodies (aCL) and cryoglobulin have been demonstrated in chronic hepatitis C. The aim of this study was to investigate these prevalences in patients with HCV-associated OLP. The prospective study investigated the role of these factors in 133 subjects: 28 with OLP-HCV(+) (group 1), 22 with OLP-HCV(-) (group 2), 33 without OLP-HCV(+) (group 3), and 50 healthy volunteers matched for age and sex served as control group (group 4). Levels of immunoglobulin G (IgG) and IgM aCL antibodies, and cryoglobulin in serum were evaluated by enzyme-linked immunosorbent assay. The prevalence of aCL in groups 1, 2, 3, and 4 were 32.1, 18, 36.3, and 8%, respectively. The positive rate of aCL was significantly higher in groups 1 and 3 than that in the control group (group 1; p=0.02 vs. the control group, group 3; p<0.01 vs. the control group). There were no significant differences in cryoglobulin among the groups. The findings of the present study showed a high prevalence of IgG and IgM aCL in the serum of patients with HCV infectious diseases. A positive factor for aCL was determined by age, sex, the presence of OLP, and HCV infection.

Brain receptor binding characteristics and pharmacokinetic-pharmacodynamic analysis of thyrotropin-releasing hormone analogues

Thyrotropin-releasing hormone (TRH) receptor binding in the rat brain after intravenous (i.v.) injections of novel TRH analogues, taltirelin and montirelin, was examined and the data were analyzed in relation to their plasma concentrations which were simultaneously determined. Taltirelin and montirelin inhibited specific [3H]-Me-TRH binding in the rat brain and their Ki values were 311 and 35.2 nM, respectively. The i.v. injection of taltirelin and montirelin (0.1-3 mg/kg) produced a significant reduction in [3H]-Me-TRH binding sites (Bmax values) in the rat brain. The reduction by both agents tended to reach a maximum after 60 min and lasted up to at least 120 min. On the other hand, the i.v. injection of both agents had little significant effect on the apparent dissociation constant (Kd) for [3H]-Me-TRH in the rat brain. Plasma concentrations of taltirelin and montirelin in rats peaked immediately after i.v. injection, and thereafter they decreased with t 1/2 of 23.0 and 14.1 min, respectively. Counter-clockwise hysteresis between the plasma concentration and receptor occupancy of these agents was observed after the i.v. injection of taltirelin and montirelin, and the temporal delay between plasma concentration and brain receptor occupancy was successfully minimized using the "effect compartment" model in combination with the "linear-effect" model. We concluded that taltirelin and montirelin exert a fairly potent effect following sustained occupation of brain TRH receptors under in vivo condition. Thus, both agents could be clinically useful for the treatment of CNS disorders.

The human SDF1 gene polymorphism is located on a mutational hot spot that was identified by the hominoid genome study

Nucleotide sequences of a part of the stromal cell-derived factor-1 (SDF-1) gene 3' untranslated region were studied among hominoids (chimpanzees, gorillas, orangutans and gibbons). An identical sequence to the human SDF1-3'G allele was found in chimpanzees and gibbons, whereas that to the 3'A allele was found in gorillas. Based on the sequence data and the hominoid phylogenetic relation, it was suggested that an adenine nucleotide at nucleotide position (np) 801 in humans and gorillas was independently introduced into each lineage after the specific divergence and an ancestral hominoid sequence of this site (np 799-802) was deduced as CCGG. The present data showing a mutational hot spot on this site suggest the possible presence of multiple origins of the worldwide distribution of the SDF1-3'A allele in humans.

Characterization of specific [3H]nociceptin binding in rat brain and spinal cord

The present study was undertaken to characterize simultaneously [3H]nociceptin binding to opioid receptor-like 1 (ORL1) receptors in the rat brain and spinal cord. Specific binding of [3H]nociceptin to crude membranes from the rat brain and spinal cord at 25 degrees C was saturable, reversible and of high affinity, and it also exhibited a pharmacological specificity involving the ORL1 receptor. The Kd and Bmax values for [3H]nociceptin in the spinal cord were significantly lower than those in the brain. At 4 degrees C, there was a significant increase in the dissociation constant (Kd) for [3H]nociceptin in the brain and spinal cord with little change in the maximal number of binding sites (Bmax) compared with that at 25 degrees C. Nociceptin and its analogue, [Phe1 psi(CH2-NH)-Gly2]nociceptin(1-13)NH2 were found to be potent inhibitors of [3H]nociceptin binding to crude membranes from the brain and spinal cord, while opioid ligands such as naloxone-benzoylhydrazone, naltrindole and nor-binaltorphimine, exhibited an inhibitory effect only at high concentrations. The Ki values for nociceptin, its analogue and opioid ligands in the spinal cord were significantly lower than those in the brain. There were regional variations in the specific [3H]nociceptin binding to crude membranes from the rat brain: a relatively high density of [3H]nociceptin binding in the cerebral cortex, hippocampus, thalamus and midbrain, moderately dense binding in the corpus striatum and pons/medulla oblongata, and the lowest density of binding in the cerebellum. In conclusion, the present study has shown that [3H]nociceptin binds selectively to ORL1 receptors in the rat brain and spinal cord.

Improved brain delivery of a nonsteroidal anti-inflammatory drug with a synthetic glyceride ester: a preliminary attempt at a CNS drug delivery system for the therapy of Alzheimer's disease

1,3-Diacetyl-2-ketoprofen glyceride (DAKG), a prodrug of ketoprofen, was synthesized as a model compound in our attempt to develop a central nervous system (CNS) drug delivery system to treat Alzheimer's disease. The primary purpose of the present study is to test whether DAKG improves the delivery of ketoprofen to the brain and to quantitatively evaluate several factors that influence the brain distribution of this prodrug. ddY mice were injected with either ketoprofen or DAKG at a dose of 40 micromol/kg and then the plasma and brain pharmacokinetics of these agents were assessed. The brain uptake clearance of ketoprofen and DAKG across the BBB was measured by in situ mouse brain perfusion. In addition, the efflux permeability of ketoprofen through the BBB was evaluated using the in vivo mouse brain microdialysis technique. The in vivo metabolism of DAKG in the brain was assessed by a short infusion into the internal carotid artery coupled with the brain metabolism index (BMI) method. Administration of DAKG produced an approximately 3-fold increase in the area under the brain concentration - time curve of ketoprofen, compared with administration of ketoprofen itself. The brain uptake clearance (CL(in) ) of ketoprofen across the BBB was 0.0308 +/- 0.0046 mL/min/g whereas the CL(in) of DAKG was 1.60 +/- 0.16 mL/min/g, suggesting a marked increase in BBB permeability following lipidization of ketoprofen. The BMI method confirmed that DAKG is taken up by the brain to rapidly release ketoprofen in a dose-dependent manner. The in vitro metabolism studies revealed that isolated bovine brain capillaries as well as whole brain homogenate have the hydrolysis activity to DAKG. In addition, the brain concentration of ketoprofen after DAKG administration was maintained for a significant period following co-administration of probenecid. These results suggest that DAKG improves the delivery of ketoprofen to the brain, and this improved delivery is due to avid uptake of DAKG across the BBB followed by rapid hydrolysis to ketoprofen within the brain. The ketoprofen produced in the brain was probably cleared by the active efflux system operating in the BBB. Significant inhibition of this efflux system by co-administration of probenecid could result in a sustained concentration of ketoprofen in the brain following DAKG administration.

Alterations in tight junctions differ between primary biliary cirrhosis and primary sclerosing cholangitis

Tight junctions (TJ) of biliary epithelial cells (BEC) and hepatocytes prevent bile regurgitation from the biliary tract. Alterations in these TJs may participate in chronic cholestatic liver diseases such as primary biliary cirrhosis (PBC) and primary sclerosing cholangitis (PSC). We examined the localization of 2 TJ proteins, ZO-1 and 7H6, in these diseases. Frozen sections from livers of PBC, PSC, extrahepatic cholestasis (Ex-C), and hepatitis C-associated cirrhosis (LC-C), as well as histologically normal livers, were processed for double-fluorescence immunohistochemistry. In controls and cirrhosis, 7H6 and ZO-1 colocalized surrounding the luminal space of the bile ducts and outlined the bile canalicular spaces between hepatocytes. In untreated PBC, immunostaining for ZO-1 in BEC of bile ducts 40 to 80 microm in diameter was preserved, but that for 7H6 was diminished to absent. In PBC treated with ursodeoxycholic acid (UDCA), immunostaining for 7H6 was well preserved. In PSC as well as in Ex-C, immunostaining for both 7H6 and ZO-1 was well preserved in bile ducts. In hepatocytes, ZO-1 showed preserved immunoreactivity, but immunostaining for 7H6 frequently disappeared. The percentage of bile ducts with immunostaining for 7H6 in all bile ducts with immunostaining for ZO-1 was significantly reduced in PBC compared with that in control, LC-C, Ex-C, and PSC (all P <.0001). Substantial alteration in the TJ protein occurs predominantly in bile ducts in PBC and in hepatocytes in PSC, suggesting increased paracellular permeability along different paracellular routes for bile regurgitation in these chronic cholestatic liver diseases.

Muscarinic receptor binding characteristics in rat tissues after oral administration of oxybutynin and propiverine

Ex vivo muscarinic receptor binding of oxybutynin and propiverine, the most commonly used anticholinergic agents for the treatment in patients with urinary incontinence, was investigated in rat tissues. The oral administration of oxybutynin (50.8 and 127 micromol/kg) caused a significant increase in the apparent dissociation constant (Kd) for specific (-)-[3H]QNB binding in the rat bladder, prostate, submaxillary gland, heart and cerebral cortex, compared with each of the control values. Also, in the submaxillary gland of these rats, there was a reduction in the maximal number of binding sites (Bmax) for (-)-[3H]QNB binding. Similarly, oral administration of propiverine at doses of 74.3-297 micromol/kg brought about a significant increase in the Kd values for (-)-[3H]QNB binding in rat tissues including the bladder, and greater increase in Kd values was seen in the rat prostate, heart and submaxillary gland. On the other hand, oral administration of propiverine, unlike oxybutynin, resulted in very little reduction in the Bmax valules for (-)-[3H]QNB binding in the submaxillary gland. In conclusion, the present study has shown that oxybutynin and propiverine, after oral administration, bind significantly to muscarinic receptors in tissues such as the bladder, which is the target organ for the treatment of urinary incontinence, and that oxybutynin appears to exhibit long-term binding to muscarinic receptors in the salivary gland.

[Species differences in the in vitro metabolism of 2,4,5,2',3',4'-hexachlorobiphenyl]

In vitro Metabolism of 2,4,5,2',3',4'-hexachlorobiphenyl (CB138) was studied using liver microsomes from rats, hamsters and guinea pigs. Guinea pig liver microsomes formed four metabolites named as M-1, M-2, M-3 and M-4 and these metabolites were all increased to about 4-5 fold of untreated microsomes by pretreatment of phenobarbital. Liver microsomes of rats and hamsters showed much less activity to metabolize CB138 than those of guinea pigs. Only phenobarbital-treated microsomes produced very small amounts of M-3 in rats and M-1, M-2 and M-3 in hamsters, but untreated and MC-treated microsomes did not. When mass spectra of the methylated derivatives of M-1, M-2, M-3 and M-4 were measured in GC/MS, the former two possess the molecular ion of 354 and the latter two had the molecular ion of 388. In addition, the mass fragmentation pattern indicated that M-1, M-2, M-3 and M-4 are 2-OH-4,5,2',3',4'-pentachlorobiphenyl, 5-OH-2,4,2',3',4'-pentachlorobiphenyl, 3-OH-CB138 and 2-OH-3,4,5,2',3',4'-hexachlorobiphenyl, respectively. Of four metabolites, the chemical structures of M-3 and M-4 were supported by the synthesized authentic compounds. From these results, it is suggested that the metabolism of CB138 in guinea pig liver proceeds mainly via 2,3-epoxide as an intermediate and a PB-inducible P450, CYP2B18, is the most important isozyme in CB138 metabolism.

Involvement of p21(WAF1/Cip1), p27(Kip1), and p18(INK4c) in troglitazone-induced cell-cycle arrest in human hepatoma cell lines

Peroxisome proliferator-activated receptor gamma (PPARgamma) regulates cell growth and differentiation. Recent evidence has suggested that PPARgamma ligands had anti-tumor effects through inhibiting cell growth and inducing cell differentiation in several types of malignant neoplasm. In the present study, we investigated: 1) the expression of PPARgamma in both human hepatoma cell lines and 5 resected human hepatocellular carcinoma (HCC) tissues; 2) the growth-inhibitory effect of troglitazone, a PPARgamma ligand, on those hepatoma cells; and 3) the molecular mechanisms of troglitazone-induced cell-cycle arrest. Five hepatoma cell lines, HLF, HuH-7, HAK-1A, HAK-1B, and HAK-5, were used. The mRNA expression levels of PPARgamma, p21(WAF1/Cip1), and p27(Kip1) were determined by real-time quantitative reverse transcription-polymerase chain reaction. The expression of cell cycle-regulating proteins, such as p21, p27, p18(INK4c), cyclin E, and pRb, was examined using Western blotting. PPARgamma was constitutively expressed in all the cell lines and the HCC tissues used in this study. A cytostatic effect of troglitazone was found in those cell lines, and this inhibition of cell growth was dosage-dependent. G0/G1 arrest was apparently demonstrated in flow cytometric analysis in HLF, HAK-1A, HAK-1B, and HAK-5, all of which showed an increased expression of p21 protein. However, HuH-7, lacking p21 protein expression, did not demonstrate clear arrest in the cell-cycle analysis. HLF, which was deficient in the protein product of the retinoblastoma tumor-suppressor gene (pRb), responded most profoundly to troglitazone, showing an increased expression in not only p21, but also in p27 and in p18. These findings suggested that p21, p27, and p18 might be involved in troglitazone-induced cell-cycle arrest in human hepatoma cells.

A mutation of the Wilson disease protein, ATP7B, is degraded in the proteasomes and forms protein aggregates

BACKGROUND & AIMS

Wilson disease is a genetic disorder characterized by the accumulation of copper in the body as a result of a defect of copper excretion from hepatocytes. The intracellular localization of the Wilson disease gene product, ATP7B, was recently identified as the late endosomes. Various mutations have been documented in patients with Wilson disease. The clinical manifestations vary greatly among the patients; however, there is little information on the genotype-phenotype correlation.

METHODS

We investigated the distribution of a common ATP7B mutant His1069Gln and a mutant Asp1270Ser by expressing the mutants tagged with green fluorescent protein in Huh7 and HEK293 cells. Intracellular organelles were visualized by fluorescence microscopy.

RESULTS

Although the wild-type ATP7B and Asp1270Ser mutant localized in the late endosomes, His1069Gln mutant did not locate in the late endosomes and was degraded by the proteasomes in the cytoplasm. Furthermore, His1069Gln formed aggresomes composed of the degradates and intermediate filaments at the microtubule-organizing center. These aggresomes were similar to Mallory bodies on electron microscopy.

CONCLUSIONS

The different protein properties of ATP7B mutants may explain the variety of clinical spectrums in patients with Wilson disease.

Sequential-replenishment mechanism of exocytosis in pancreatic acini

Here we report exocytosis of zymogen granules, as examined by multiphoton excitation imaging in intact pancreatic acini. Cholecystokinin induces Ca 2+ oscillations that trigger exocytosis when the cytosolic Ca 2+ concentration exceeds 1 microM. Zymogen granules fused with the plasma membrane maintain their Omega-shaped profile for an average of 220 s and serve as targets for sequential fusion of granules that are located within deeper layers of the cell. This secondary exocytosis occurs as rapidly as the primary exocytosis and accounts for most exocytotic events. Granule-granule fusion does not seem to precede primary exocytosis, indicating that secondary fusion events may require a plasma-membrane factor. This sequential-replenishment mechanism of exocytosis allows the cell to take advantage of a large supply of fusion-ready granules without needing to transport them to the plasma membrane.

Comparative report on transplantation and relevant ethical problems in five European countries, and some reflections on Japan

Comparison of transplantation medicine in Sweden, Denmark, Germany, Spain and Portugal reveals many and important differences with respect to frequency of transplantations, frequency of life donations, legal regulations and influence of the family on organ donation. The differences observed are at least partly related to cultural and value differences between the various countries, but many questions need to be studied systematically and in more detail before useful conclusions can be drawn. One study would have to address the problem of how differences in the family influence on organ donation can be explained. Another question needing further clarification concerns the exact meaning of "medical decision" and "medical criteria" because these terms, on which access to- and selection from the waiting list largely depends, are equivocally defined and seem to differ according to different traditions. Open questions also arise with respect to the influence of "closeness or distance" on medical decision making. The findings indicate that it would be premature to propose common guidelines to be observed within Europe as long as the above mentioned and some further questions have not been systematically studied and thoroughly analyzed.

Relation of type II transforming growth factor-beta receptor to hepatic fibrosis and hepatocellular carcinoma

Hepatocarcinogenesis is closely related to hepatic fibrosis. In this study, we investigated the relationship of type II transforming growth factor-beta receptor (T beta RII) to hepatic fibrosis and hepatocellular carcinoma (HCC). In vivo: liver tissues were obtained from 30 patients (10 chronic hepatitis, 7 cirrhosis, 13 HCC). Protein expression and immunolocalization of T beta RII were examined by Western blot analysis and immunohistochemistry. In vitro: T beta RII protein expression in hepatoma cell lines (HepG2, Hep3B, HLE, HLF and Huh7) was examined by Western blot analysis. Next, we transfected T beta RII cDNA to Huh7, and compared the change of cell number and observed the induction of apoptosis after TGF-beta1 treatment using a FACScan flow cytometer. In vivo: T beta RII immunolocalization in liver tissues was significantly decreased in patients with HCC compared with that of patients with chronic hepatitis or liver cirrhosis. In Western blot analysis, T beta RII expression in tissues attenuated in comparison with that in non-tumor tissues in some patients with HCC. In vitro: T beta RII protein expression in HLE, HLF and Huh7 cells was weaker than that in HepG2 and Hep3B cells. In Huh7 cells transfected T beta RII cDNA, cell arrest and apoptosis were obviously induced. These results indicated that human HCC has a reduced expression of T beta RII for TGF-beta1. This may provide a selective growth advantage to HCC to escape the inhibitory growth signals of TGF-beta1, and may be linked with critical steps in the growth of hepatoma cells.

In vivo demonstration of alpha(1A)-adrenoceptor subtype selectivity of KMD-3213 in rat tissues

The present study was undertaken to characterize the in vivo alpha(1)-adrenoceptor binding of KMD-3213, a novel selective antagonist of alpha(1A)-adrenoceptors, in rat tissues by using a tritiated ligand with high specific activity, in comparison with that of [(3)H]prazosin. A significant degree of in vivo specific binding of [(3)H]KMD-3213 after i.v. injection of the radioligand (1. 4 nmol/kg) was seen in most rat tissues, except the cerebral cortex, spleen, and liver, which showed a little or no specific binding. There was a notable difference among tissues in the time course of specific [(3)H]KMD-3213 binding after i.v. injection of the ligand. The specific binding in the lung, kidney, and spleen was greatest at 10 min and declined rapidly with the disappearance of the ligand from the plasma. On the other hand, [(3)H]KMD-3213 binding in the submaxillary gland, vas deferens, and prostate attained peak levels at 60 min, and a considerable degree of binding was present even at 240 min. After i.v. injection of a similar dose (1.2 nmol/kg) of [(3)H]prazosin in rats, the in vivo specific binding in the submaxillary gland was greatest at 10 min and then it fell rapidly, whereas [(3)H]prazosin binding in the spleen attained a peak level at 60 min, and this was maintained even at 120 min. The AUC(0-120) values of the specific binding for [(3)H]KMD-3213, compared with those of [(3)H]prazosin, were markedly lower in the rat aorta, spleen, and liver, whereas the prostate, submaxillary gland, and lung showed significantly higher AUC(0-120) values of [(3)H]KMD-3213 compared with [(3)H]prazosin. Furthermore, the in vivo specific binding of [(3)H]KMD-3213 at dose ranges of 1.4 to 13.6 nmol/kg increased linearly in the prostate and submaxillary gland, but did not increase in a dose-dependent manner in the spleen. On the other hand, there was a dose-dependent increase in the in vivo specific binding of [(3)H]prazosin at doses of 1.2 to 10.6 nmol/kg in all tissues. The in vivo specific binding of [(3)H]KMD-3213 in rat tissues was reduced by concomitant i.v. injection of low doses of prazosin in a dose-dependent manner, but not by even a relatively high dose of yohimbine. In conclusion, the present study shows that KMD-3213 binds to the alpha(1A)-adrenoceptor subtype with a higher affinity than to the alpha(1B)- and alpha(1D)- subtypes under in vivo condition, thus leading to prostate selectivity.

Disposition and alpha(1)-adrenoceptor binding characteristics of JTH-601 and its metabolites in rat tissues

The present study was performed to characterize the disposition and alpha(1)-adrenoceptor binding of JTH-601, a novel alpha(1L)-adrenoceptor antagonist, and its metabolites (beta-D-glucopyranosyl uronic acid, JTH-601-G1; hydrogen sulfate, JTH-601-S1) in the rat prostate and other tissues. JTH-601, JTH-601-G1, and JTH-601-S1 inhibited competitively specific [(3)H]tamsulosin binding in the prostate, submaxillary gland, and spleen of rats in vitro, and the inhibitory effect of JTH-601 was 2. 5 to 6.4 times more potent than that of its metabolites. JTH-601 and its metabolites inhibited dose dependently in vivo specific [(3)H]tamsulosin binding in the particulate fraction of the prostate, aorta, submaxillary gland, and spleen of rats. Compared with that of JTH-601, the in vivo inhibitory effect of JTH-601-G1 was 1.9 to 2. 9 times more potent, and the effect of JTH-601-S1 was 1.3 to 3.2 times less potent. Based on the ratios of ID(50) values, JTH-601 and JTH-601-G1 appeared to be 4.0 to 6.9 times more selective than prazosin as far as the alpha(1)-adrenoceptors in the prostate and submaxillary gland versus the spleen or aorta were concerned. The total radioactivity in rat tissues after i.v. injection of [(3)H]JTH-601-G1 was considerably lower than that of [(3)H]JTH-601. The plasma concentration of [(3)H]JTH-601-G1 at 10 min after i.v. injection in rats was 3 times higher than that of [(3)H]JTH-601, and conversely, the concentration in the prostate was 3 times lower. Although in vivo [(3)H]JTH-601-G1 binding at 10 min was significantly lower than that of [(3)H]JTH-601 in most rat tissues, there was comparable binding between these radioligands in the prostate and vas deferens. Specific binding of [(3)H]JTH-601, at 60 min after i.v. injection compared with that at 10 min, was considerably reduced in rat tissues except the prostate and vas deferens, both of which showed relatively sustained binding. In conclusion, the present study has shown that JTH-601 and its metabolites bind to alpha(1)-adrenoceptors in rat tissues in vivo and that JTH-601-G1 retains the prostatic alpha(1)-adrenoceptor subtype selectivity of its parent compound.

Identification of novel first exons in Ad4BP/SF-1 (NR5A1) gene and their tissue- and species-specific usage

It has been demonstrated that the mammalian Ad4BP/SF-1 (NR5A1) gene is regulated precisely in sex, tissue, and developmental stage specific manners. To clarify the complex transcriptional regulation, we investigated in the present study whether the gene transcription is regulated by multiple promoters accompanied by noncoding first exons. Novel first exons (Io and Ig) were identified downstream of the already identified exon Ia. Nucleotide sequences revealed that Ia and Ig exons were well conserved, whereas Io exon was less conserved among the mouse, rat, and human genes. Interestingly, the splice donor of the mouse and human Io and human Ig exons do not satisfy the consensus sequence. Transcripts containing Ia, Io, and Ig were detected in all rat tissues examined, while the transcript containing Io was undetectable in the corresponding tissues of mice. The lack of exon Io usage in the mouse was confirmed by transient transfection assays with cultured cells. Quantitative RT-PCR analysis revealed that the transcript containing Ig exon was the main product in the pituitary but significantly less in the spleen, suggesting that the regulation of Ad4BP/SF-1 gene transcription in the pituitary and spleen is distinct from that of other tissues. The above findings, together with the structural abnormality at the splice donor site, suggest that acquisition of the multiple first exons enables the Ad4BP/SF-1 gene to be regulated differentially in different animal species and in different tissues in the same animal.