Immunohistochemical study of tyrosine phosphorylation signaling in Hassall's corpuscles of the human thymus

Tyrosine phosphorylation signaling has been reported to play a key role in thymocyte development. However, the physiological role of signaling in thymus stroma is poorly understood, and there is lack of information on the in situ localization of elements of the signaling pathway in thymus stroma. In the present study, we have found by immunohistochemical analysis that tyrosine-phosphorylated proteins are present in high amounts in Hassall's corpuscles of the thymus medulla. Hassall's corpuscles represent end stages of maturation of thymic medullary epithelium. We have also investigated the localization of the src family that is involved in tyrosine phosphorylation signaling in Hassall's corpuscles. A member of the src family protein tyrosine kinases, p59fyn, was shown to be abundantly expressed in the outer layer of Hassall's corpuscles. Another member of the family, p60c-src, was highly expressed in the entire Hassall's corpuscles. Furthermore, p50csk and p130cas, both of which are involved in the pathway, were shown to be preferably expressed in the outer layer of Hassall's corpuscles. These findings suggest that tyrosine phosphorylation signaling may play a role in thymic medullary epithelial maturation and that the src family is involved in the process.

Itai-itai disease is not associated with polymorphisms of the estrogen receptor alpha gene

Itai-itai (or ouch-ouch) disease is a syndrome accompanied by bone mineral disorders, and which may be related to oral cadmium exposure. Itai-itai predominantly affects postmenopausal women with a history of multiple childbirths. Recently, it has been reported that polymorphisms of the estrogen receptor alpha (ERalpha) gene are associated with postmenopausal reduction of bone mineral density in Japanese women. However, estrogen receptors have never been studied in itai-itai disease. In this study, we examined the genotypic distributions of PvuII and XbaI restriction fragment length polymorphisms (RFLPs) of the ERalpha gene in patients with itai-itai disease and compared them with those of control subjects. The RFLPs are represented here as Pp (PvuII) and Xx (XbaI); the capital and small letters signify the absence and presence of restriction sites, respectively. The genotypic distributions of the patient group were: PP, 14.8%; Pp, 55.6%; pp, 29.6%; XX, 7.4%; Xx, 29.6%; and xx, 63.0%. These distributions were similar to those observed for the control groups, hence no pattern of genotypic distribution was observed that could be related to itai-itai disease. We conclude that RFLPs of the ERalpha gene may not be associated with itai-itai disease.

Value of percutaneous transhepatic portography before hepatectomy for hilar cholangiocarcinoma

BACKGROUND

The diagnostic value of percutaneous transhepatic portography (PTP) for assessing cancer invasion of the portal bifurcation in patients with hilar cholangiocarcinoma has not been studied previously.

METHODS

From April 1977 to March 1998 combined hepatobiliary and portal vein resection was performed in 45 patients. In 25 patients, PTP was carried out before operation and the resected portal bifurcation was examined histologically. Correlation between portographic and microscopic findings at the portal bifurcation was studied retrospectively.

RESULTS

Portographic and microscopic findings were classified into three groups (type A, B or C, and grade 0, I or II respectively) according to the findings at the portal bifurcation. There was a significant correlation between the portographic type and degree of cancer invasion (P = 0.0001). In seven of the eight patients with type A portograms, there was no microscopic cancer invasion of the portal bifurcation. In 15 of the 17 patients with type B or C portograms, cancer invasion was found microscopically. All patients with microscopic grade II invasion had type C portograms.

CONCLUSION

PTP can be used to evaluate cancer invasion of the portal bifurcation with sufficient reliability for preoperative staging of hilar cholangiocarcinoma.

Haplotype analysis of a de novo allele at a vWF STR locus using flanking STR loci

We have detected an unusual allele at the vWF-Kimpton (vWF-K) loci in the DNA of a child (genotype: 1415) in a paternity trio case. One allele of the child's DNA was found to derive neither from the mother (1214) nor from the putative father (1314), whose paternity was established not only by conventional polymorphic markers (probability 0.99999) but also by the other 10 STRs and the D1S80 and HLA DQ alpha loci. Two STRs flanking vWF-K comprise vWF haplotypes, which allow the parental origin of the unusual allele to be determined. Sequencing of clones encompassing the three STRs showed that the unusual allele segregated with the paternal haplotype. The de novo allele of the child thus seemed to be generated from the longer allele (14) by gaining a single unit (TCTA) through slippage replication.

Structure-activity relationships of calcicludine and dendrotoxin-I, homologous peptides acting on different targets, calcium and potassium channels

Calcicludine (CaC) and dendrotoxin-I (DTX-I) possess high homology of their primary structures despite their different biological activities acting on calcium and potassium channels, respectively. In order to elucidate the channel specificity displayed by these toxins, their three-dimensional structures were compared by NMR. These analyses revealed that their overall conformations are similar except for the structure at the N-terminus. To demonstrate the significance of this N-terminal, chimeric peptides, CaC(1-30)/DTX-I(31-60) and DTX-I(1-30)/CaC(31-60), were synthesized. The CD spectra and receptor-binding measurements of chimeric peptides indicated that the contribution to the overall conformation and to the affinity of the N-terminal part of molecule seem to be more important than that of the C-terminal one. These results suggest that the N-terminal part may participate in distinguishing between calcium and potassium channels.

C/EBPbeta and GATA-1 synergistically regulate activity of the eosinophil granule major basic protein promoter: implication for C/EBPbeta activity in eosinophil gene expression

Eosinophil granule major basic protein (MBP) is expressed exclusively in eosinophils and basophils in hematopoietic cells. In our previous study, we demonstrated a major positive regulatory role for GATA-1 and a negative regulatory role for GATA-2 in MBP gene transcription. Further analysis of the MBP promoter region identified a C/EBP (CCAAT/enhancer-binding protein) consensus binding site 6 bp upstream of the functional GATA-binding site in the MBP gene. In the cell line HT93A, which is capable of differentiating towards both the eosinophil and neutrophil lineages in response to retinoic acid (RA), C/EBPalpha mRNA expression decreased significantly concomitant with eosinophilic and neutrophilic differentiation, whereas C/EBPbeta expression was markedly increased. Electrophoretic mobility shift assays (EMSAs) showed that recombinant C/EBPbeta protein could bind to the potential C/EBP-binding site (bp -90 to -82) in the MBP promoter. Furthermore, we have demonstrated that both C/EBPbeta and GATA-1 can bind simultaneously to the C/EBP- and GATA-binding sites in the MBP promoter. To determine the functionality of both the C/EBP- and GATA-binding sites, we analyzed whether C/EBPbeta and GATA-1 can stimulate the MBP promoter in the C/EBPbeta and GATA-1 negative Jurkat T-cell line. Cotransfection with C/EBPbeta and GATA-1 expression vectors produced a 5-fold increase compared with cotransfection with the C/EBPbeta or GATA-1 expression vectors individually. In addition, GST pull-down experiments demonstrated a physical interaction between human GATA-1 and C/EBPbeta. Expression of FOG (riend ATA), which binds to GATA-1 and acts as a cofactor for GATA-binding proteins, decreased transactivation activity of GATA-1 for the MBP promoter in a dose-dependent manner. Our results provide the first evidence that both GATA-1 and C/EBPbeta synergistically transactivate the promoter of an eosinophil-specific granule protein gene and that FOG may act as a negative cofactor for the eosinophil lineage, unlike its positively regulatory function for the erythroid and megakaryocyte lineages.

[A case of glomangioma of the stomach]

Glomus tumor of the stomach is still a rare disease. In Japan, till now, only 78 cases have been reported as far as we look over the literatures. We report a case of glomangioma of the stomach. The patient is a 44-years old female who underwent a medical examination and pointed out a gastric submucosal tumor, but she had no symptoms and admitted for operation. The endoscopical finding was a submucosal tumor as large as 4 cm, and the result of biopsy was chronic atrophic gastritis. So typical gastrectomy was performed without a definite diagnosis. In the cross section, the tumor was clearly bounded gastric mucosa by a white membrane, and the center of the tumor was spongy. By patho-histological and electro-microscopic study, we diagnosed that the tumor was glomangioma in the classification of Weiss & Enzinger. The patient was getting on well after the operation and left the hospital on the 29th day.

Binding affinity of sarpogrelate to 5-HT(2A) receptor ligand recognition sites in rat renal cortical and mesangial cells in culture

We detected specific binding of 3H-ketanserin (0.6 nM) in rat renal cortical membrane preparations (4.70 +/- 0.57 fmol/mg protein) and mesangial cells (7.55 +/- 0.92 fmole/10(6) cells). Thus, the value in the renal cortical membrane corresponded to 15% of that in the cerebral cortical membranes (30.0 +/- 2.9 fmole/mg protein). The affinity of 3H-ketanserin binding displacement activities by sarpogrelate, a selective 5-HT2A receptor antagonist, in the renal cortical membrane (IC50; 0.448 +/- 0.061 microM) and mesangial cells (IC50; 0.656 +/- 0.187 microM) were almost 100-fold less than that in the cerebral cortical membrane (IC50; 4.62 +/- 1.02 nM). In the renal cortical membranes and mesangial cells, methysergide displaced a tiny fraction of 3H-ketanserin binding at concentrations up to 10 microM. These results did not explain the functional activity of 5-HT in the mesangial cells, and we conclude that specific 3H-ketanserin binding sites in the mesangial cells consisted of methysergide-resistant and non-serotonergic sites with low affinity for sarpogrelate.

Critical role of sulfenic acid formation of thiols in the inactivation of glyceraldehyde-3-phosphate dehydrogenase by nitric oxide

The relationship between possible modifications of the thiol groups of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) by nitric oxide (NO) and modified enzyme activity was examined. There are 16 free thiols, including 4 active site thiols, in a tetramer of GAPDH molecule. NO donors, sodium nitroprusside (SNP), and S-nitroso-N-acetyl-DL-penicillamine (SNAP) decreased the number of free thiols with a concomitant inhibition of GAPDH activity in a concentration- and time-dependent manner. After treatment for 30 min, free thiols were maximally decreased to 8-10 per GAPDH tetramer and enzyme activity was also inhibited to 5-10% of control activity. In the presence of 30 mM dithiothreitol (DTT), these effects were completely blocked. Since similar results were obtained in the case of hydrogen peroxide (H2O2) treatment, which is known to oxidize the thiols, these effects of nitric oxide donors were probably due to modification of thiol groups present in a GAPDH molecule. On the other hand, DTT posttreatment after the treatment of GAPDH with SNP, SNAP, or H2O2 did not completely restore the modified thiols and the inhibited enzyme activity. DTT posttreatment after the 30-min-treatment with these agents restored free thiols to 14 in all treatments. In the case of SNAP treatment, all 4 active sites were restored and enzyme activity reached more than 80% of the control activity, but in two other cases one active site remained modified and enzyme activity was restored to about only 20%. Therefore, all 4 free thiols in the active site seem to be very important for full enzyme activity. DTT posttreatment in the presence of sodium arsenite, which is known to reduce sulfenic acid to thiol, almost completely restored both thiol groups and enzyme activity. These findings suggest that nitric oxide inhibits GAPDH activity by modifications of the thiols which are essential for this activity, and that the modification includes formation of sulfenic acid, which is not restored by DTT. S-nitrosylation, which is one type of thiol modification by NO, occurred when GAPDH was treated with SNAP but not SNP. Analysis of thiol modification showed that SNAP preferentially nitrosylated the active site thiols, the nitrosylation of which fully disappeared by DTT posttreatment. It seems that SNAP nitrosylates the active site thiols of GAPDH to prevent these thiols from oxidizing to sulfenic acid.

Origin and phylogenetic distribution of Alu DNA repeats: irreversible events in the evolution of primates

Over the past 60 million years, or so, approximately one million copies of Alu DNA repeats have accumulated in the genome of primates, in what appears to be an ongoing process. We determined the phylogenetic distribution of specific Alu (and other) DNA repeats in the genome of several primates: human, chimpanzee, gorilla, orangutan, baboon, rhesus, and macaque. At the population level studied, the majority of the repeats was found to be fixed in the primate species. Our data suggest that new Alu elements arise in unique, irreversible events, in a mechanism that seems to preclude precise excision and loss. The same insertions did not arise independently in two species. Once inserted and genetically fixed, the DNA elements are retained in all descendant lineages. The irreversible expansion of Alu s introduces a vector of time into the evolutionary process, and provides realistic (rather than statistical) answers to questions on phylogenies. In contrast to point mutations, the present distribution of individual Alu s is congruent with just one phylogeny. We submit that only irreversible and taxonomically relevant events are at the molecular basis of evolution. Most point mutations do not belong to this category.

Mediators of nonadrenergic, noncholinergic relaxation in longitudinal muscle of the intestine of ICR mice

Mediators of nonadrenergic, noncholinergic (NANC) relaxation in longitudinal muscle of several regions of ICR mouse intestine were studied. An inhibitor of synthesis of nitric oxide, N(G)-nitro-L-arginine (L-NOARG) at 10 microM significantly inhibited NANC relaxations induced by electrical field stimulation (EFS) in the jejunum, ileum, and the proximal and distal colon. Especially in the ileum extent of the inhibition was more than 80%. An antagonist of vasoactive intestinal peptide (VIP) receptors, VIP(10-28) at 3 microM partially inhibited the EFS induced relaxations in the jejunum and proximal colon, but very slightly in the distal colon and had no effect in the ileum. An antagonist of pituitary adenylate cyclase activating peptide (PACAP) receptor, PACAP(6-38) at 3 microM partially inhibited the EFS-induced relaxations in the proximal and distal colon, but not in the jejunum and ileum. Totals of the percentages of relaxant components mediated by nitric oxide, VIP and PACAP in every region are roughly equal to a hundred percent. In another series of experiments, EFS-induced relaxations were almost completely inhibited by the treatment of the segments with L-NOARG and VIP(10-28) in the jejunum, with L-NOARG, VIP(10-28) and PACAP(6-38) in the proximal colon, and with L NOARG and PACAP(6-38) in the distal colon. The present results suggest that nitric oxide solely mediates the relaxation of longitudinal muscle of the ileum of ICR mice, whereas nitric oxide and VIP co-mediate it in the jejunum, nitric oxide, VIP and PACAP in the proximal colon, and nitric oxide and PACAP in the distal colon.

Hybrid survival motor neuron genes in Japanese patients with spinal muscular atrophy

Spinal muscular atrophy (SMA) is a frequently occurring autosomal recessive disease, characterized by the degeneration of spinal cord anterior horn cells, leading to muscular atrophy. Most SMA patients carry homozygous deletions of the telomeric survival motor neuron gene (SMN) exons 7 and 8. In the study presented here, we examined 20 Japanese SMA patients and found that 4 of these patients were lacking in telomeric SMN exon 7, but retained exon 8. In these 4 patients, who exhibited all grades of disease severity, direct sequencing analysis demonstrated the presence of a hybrid SMN gene in which centromeric SMN exon 7 was adjacent to telomeric SMN exon 8. In an SMA family, a combination of polymerase chain reaction and enzyme-digestion analysis and haplotype analysis with the polymorphic multicopy marker Agl-CA indicated that the patient inherited the hybrid gene from her father. In conclusion, hybrid SMN genes can be present in all grades of disease severity and inherited from generation to generation in an SMA family.

Advanced adenosquamous carcinoma of the gallbladder with bilio-biliary fistula: an uncommon case treated by hepatopancreatoduodenectomy

A 70 year-old female, who presented with jaundice and abdominal pain, was found to have an advanced gallbladder cancer involving the liver parenchyma, duodenum, and transverse colon. This was complicated by a bilio-biliary fistula between the gallbladder and both the right and left hepatic ducts. After obtaining an accurate pre-operative diagnosis, the patient underwent hepatopancreatoduodenectomy (HPD) with lymph node dissection around the hepatic pedicle, celiac trunk, aorta, and inferior vena cava. Histologic examination revealed adenosquamous carcinoma. This rare variant accounts for 3.5% of gallbladder cancers, and is associated with a worse prognosis than adenocarcinoma. The patient is in good condition without any signs of recurrence 42 months after the HPD. In this case report, we discuss the histological type and internal biliary fistula with regard to the literature, and the usefulness of an aggressive surgical procedure such as HPD with extended lymph node dissection which can improve survival and quality of life in selected patients.

Possible involvement of calcineurin, protein kinase C, and Src-family kinases in angiotensin II-induced tyrosine phosphorylation of p130cas in rat cardiac muscle

Anigiotensin II (AII) has been documented to induce cardiac hypertrophy and rapid tyrosine phosphorylation of multiple intracellular substrates including 120 kD and 70 kD protein in cardiac cells. We have found that the 120 kD protein is a Crk-associated Src substrate, p130(cas). Specific inhibition of Src-family tyrosine kinases attenuated the AII-induced p130(cas) tyrosine phosphorylation. Either chelation of intracellular Ca(2+) or inhibition of protein kinase C resulted in the decrease of the phosphorylation. Further, we have investigated the relationship between the AII-induced p130(cas) tyrosine phosphorylation and a Ca(2+) and calmodulin dependent protein phosphatase calcineurin which is known to be involved in the signaling pathway of cardiac hypertrophy. Pretreatment with an immunosuppressant cyclosporin A, a specific inhibitor of calcineurin, resulted in the decrease of the phosphorylation. These findings strongly suggest that the AII-induced p130(cas) tyrosine phosphorylation might be associated with the signaling pathways of Src-family tyrosine kinases, protein kinase C and calcineurin in rat cardiac muscle.

Molecular cloning of cDNA encoding human Rab3D whose expression is upregulated with myeloid differentiation

To identify genes expressed in myeloid differentiation, we isolated a cDNA fragment by differential display using RNA prepared from HT93A cells, a human cell line capable of differentiating into neutrophil and eosinophil lineages in response to retinoic acid (RA). Evaluation of the full-length clone isolated from an HT93A cDNA library showed that it encoded a 24 kDa protein comprised of several domains conserved in the Ras superfamily. Comparison of the deduced amino acid sequence of this clone with Rab proteins revealed that it had highest homology to a small GTP-binding protein, murine Rab3D. The mRNA expression of human Rab3D was upregulated in the course of myeloid differentiation, and it was preferentially expressed in granulocytes. These results suggest that human Rab3D may play a specific role in granulocytes, for example in exocytosis of neutrophil-specific granules or in degranulation of both eosinophils and basophils.

Tyrosine kinase involvement in apamin-sensitive inhibitory responses of rat distal colon

1. It has been suggested that pituitary adenylate cyclase activating peptide (PACAP) may be involved in the non-adrenergic, non-cholinergic (NANC) inhibitory response of longitudinal muscle of rat distal colon. In this study, we have investigated the intracellular mechanism of PACAP-induced relaxation in this muscle. 2. PACAP induced an apamin-sensitive relaxation of the longitudinal muscle. The tyrosine kinase inhibitors genistein at 10 microM and tyrphostin 25 at 30 microM, but not the cyclic AMP-dependent protein kinase inhibitor Rp-8-bromoadenosine-3',5'-cyclic monophosphorothioate at 30 microM significantly inhibited the PACAP-induced relaxation to 60% and 25% of control values, respectively. PACAP did not increase the cyclic AMP content of the muscle. 3. Tyrphostin 25 at 10 microM significantly inhibited the relaxation of longitudinal muscle induced by electrical field stimulation (EFS), to 50% of control values. Apamin at 1 microM, an antagonist of small conductance Ca2+-activated K+ channels, also inhibited the relaxation, to 42 % of control values. The inhibitory effects of tyrphostin 25 and apamin were not additive (44 % of control values). 4. PACAP induced an apamin-sensitive, slow hyperpolarization of the cell membrane of the muscle. Tyrphostin 25 at 3 microM inhibited this PACAP-induced hyperpolarization. Tyrphostin 25 at 10 microM and genistein at 10 microM inhibited the apamin-sensitive inhibitory junction potentials induced by a single pulse of EFS. 5. The PACAP-induced relaxation of longitudinal muscle occurred with a concomitant decrease in intracellular Ca2+ levels ([Ca2+]i). Tyrphostin 25 at 10 microM and apamin at 1 microM abolished these PACAP-induced responses. 6. From these findings it is suggested that the activation of tyrosine kinase is involved in PACAP-induced relaxation of longitudinal muscle from rat distal colon, 'upstream of' the activation of apamin-sensitive K+ channels.

High incidence of a survival motor neuron gene/cBCD541 gene ratio of 2 in Japanese parents of spinal muscular atrophy patients: a characteristic background of spinal muscular atrophy in Japan?

Most spinal muscular atrophy (SMA) patients lack the survival motor neuron gene (SMN). However, the patients retain at least one copy of the cBCD541 gene (BCD), which is highly homologous with SMN. Here, we determined the SMN/BCD copy number ratios (the S/B ratios) of 12 parents of Japanese SMA patients with a homozygous SMN deletion, using competitive oligonucleotide priming polymerase chain reaction. We identified an S/B ratio of 2 in 25% of the parents examined, whereas less than 2% of parents of SMA patients in Western populations have an S/B ratio of 2. The high incidence of an S/B ratio of 2 in Japanese parents of SMA patients may reflect the characteristic genetic background of SMA in Japan.

The inhibitory effect of glabridin from licorice extracts on melanogenesis and inflammation

Glabridin is the main ingredient in hydrophobic fraction of licorice extract affecting on skins. In this study, we investigated inhibitory effects of glabridin on melanogenesis and inflammation using cultured B16 murine melanoma cells and guinea pig skins. The results indicated that glabridin inhibits tyrosinase activity of these cells at concentrations of 0.1 to 1.0 microg/ml and had no detectable effect on their DNA synthesis. Combined analysis of SDS-polyacrylamide gel electrophoresis and DOPA staining on the large granule fraction of these cells disclosed that glabridin decreased specifically the activities of T1 and T3 tyrosinase isozymes. It was also shown that UVB-induced pigmentation and erythema in the skins of guinea pigs were inhibited by topical applications of 0.5% glabridin. Anti-inflammatory effects of glabridin in vitro were also shown by its inhibition of superoxide anion productions and cyclooxygenase activities. These data indicated that glabridin is a unique compound possessing more than one function; not only the inhibition of melanogenesis but also the inhibition of inflammation in the skins. By replacing each of hydroxyl groups of glabridin with others, it was revealed that the inhibitory effect of 2'-O-ethyl glabridin was significantly stronger than that of 4'-O-ethyl-glabridin on melanin synthesis in cultured B16 cells at the concentration of 1.0 mg/ml. With replacement of both of two hydroxyl groups, the inhibitory effect was totally lost. Based on these data, we concluded that two hydroxyl groups of glabridin are important for the inhibition of melanin synthesis and that the hydroxyl group at the 4' position of this compound is more closely related to melanin synthesis.

Inhibition of skeletal muscle sarcoplasmic reticulum Ca2+-ATPase by nitric oxide

The effects of nitric oxide on the activities of thapsigargin-sensitive sarcoplasmic reticulum Ca2+-ATPase (SERCA) and Ca2+ uptake by sarcoplasmic reticulum (SR) membranes prepared from white skeletal muscle of rabbit femoral muscle were studied. Pretreatment of the SR preparations with nitric oxide at concentrations of up to 250 microM for 1 min decreased the SERCA activity concentration dependently, and also decreased their Ca2+ uptake. Both these effects of nitric oxide were reversible. Inhibitors of guanylyl cyclase and protein kinase G (PKG) had no significant effect on the nitric oxide-induced inhibitions of SERCA and Ca2+ uptake. Moreover, dithiothreitol did not reverse the inhibitory effects of nitric oxide on SERCA and Ca2+ uptake. These findings suggest that nitric oxide inhibits SERCA, mainly SERCA 1, of rabbit femoral skeletal muscle by an action independent of the cyclic GMP-PKG system or oxidation of thiols, and probably by a direct action on SERCA protein.

Chemical synthesis of the precursor molecule of the Aequorea green fluorescent protein, subsequent folding, and development of fluorescence

The present paper describes the total chemical synthesis of the precursor molecule of the Aequorea green fluorescent protein (GFP). The molecule is made up of 238 amino acid residues in a single polypeptide chain and is nonfluorescent. To carry out the synthesis, a procedure, first described in 1981 for the synthesis of complex peptides, was used. The procedure is based on performing segment condensation reactions in solution while providing maximum protection to the segment. The effectiveness of the procedure has been demonstrated by the synthesis of various biologically active peptides and small proteins, such as human angiogenin, a 123-residue protein analogue of ribonuclease A, human midkine, a 121-residue protein, and pleiotrophin, a 136-residue protein analogue of midkine. The GFP precursor molecule was synthesized from 26 fully protected segments in solution, and the final 238-residue peptide was treated with anhydrous hydrogen fluoride to obtain the precursor molecule of GFP containing two Cys(acetamidomethyl) residues. After removal of the acetamidomethyl groups, the product was dissolved in 0.1 M Tris. HCl buffer (pH 8.0) in the presence of DTT. After several hours at room temperature, the solution began to emit a green fluorescence (lambdamax = 509 nm) under near-UV light. Both fluorescence excitation and fluorescence emission spectra were measured and were found to have the same shape and maxima as those reported for native GFP. The present results demonstrate the utility of the segment condensation procedure in synthesizing large protein molecules such as GFP. The result also provides evidence that the formation of the chromophore in GFP is not dependent on any external cofactor.

Decrease in participation of nitric oxide in nonadrenergic, noncholinergic relaxation of rat intestine with age

Participation of nitric oxide in the electrical field stimulation-induced nonadrenergic, noncholinergic (NANC) relaxation in various intestinal regions was studied in 2- to 50-week-old Wistar rats. In the jejunum of 2-week-old rats, the extent of the nitric oxide-mediated component of the relaxation of longitudinal muscle was approximately 60-70%, whereas the component was 40-50% in 4-week-old rats and was absent in 8- and 50-week-old rats. Thus, nitric oxide seems to be the most important mediator at young ages but its significance is lost with age. The same tendency as that in the jejunum was also shown in longitudinal muscle of the ileum, proximal and distal colon, and rectum. The tendency was also shown in the circular muscle of the rectum. Sensitivity of the longitudinal muscle of the jejunum and proximal colon to exogenously added nitric oxide was high in younger rats. Immunoreactive structures for nitric oxide synthase were observed in the circular muscle layer of the rectum. The population of the structures was denser in 4-week-old than that in 50-week-old. The results suggest that NANC relaxation in every region of the intestine at 2-week-old is almost solely mediated by nitric oxide, and its significance as an inhibitory mediator gradually or rapidly decreases with age.

[MR cholangiopancreatography using respiratory triggered half-Fourier RARE technique]

We evaluate the usefulness of MRCP using respiratory triggered HASTE technique in 68 patients. Eleven subsequent slices were obtained for MRCP. To determine the optimal trigger rate, MRCP with various trigger rates were compared in 25 patients. Respiratory triggered MRCP and breath hold MRCP were compared in 68 patients. Respiratory triggered MRCP was also performed in 3 infants. The optimal trigger rate was 10%. In 17 patients who could not stop their breath for 10 seconds, respiratory triggered MRCP were better than breath hold MRCP in 14 (82%) for the source images and in 17 (100%) for the MIP images. Respiratory triggered MRCP could depict cystic duct and main pancreatic duct even in 14 month infant. MRCP with high spatial resolution could be obtained with respiratory triggered HASTE technique in critically ill, or non-cooperative patients.

[Genetic analysis including predictive DNA testing in a Japanese family with dentatorubral-pallidoluysian atrophy]

Dentatorubral-pallidoluysian atrophy (DRPLA) is a neurodegenerative disease showing autosomal dominant inheritance, which is associated with a specific trinucleotide repeat expansion in the DRPLA gene. We performed DNA analysis of two affected and one non-affected individuals of a Japanese family with DRPLA. The proband (case 1) developed seizures at age 17, and these gradually evolved to intractable myoclonic epilepsy. His father (case 2) had manifested gait disturbance since the age of 40, which was followed by progressive dementia. DNA analysis disclosed that these patients had an expanded CAG repeat in the DRPLA gene, which confirmed the diagnosis. The brother of case 1, who was asymptomatic, expressed a desire to undergo predictive DNA testing for DRPLA. We discussed the ethical and social issues of this predictive testing, and decided to carry out the testing after obtaining informed consent from him and his wife. The test revealed no expanded allele, thus proving that he would not develop DRPLA, and relieving him of his fears. Our results suggest that predictive testing improves the psychological well-being of non-affected individuals in DRPLA families.

[Optimal scan parameters of MRCP using HASTE]

For improving the image of fine structures on MRCP, optimal scan parameters were assessed by water-filled phantom using HASTE sequence. Spatial resolution and Contrast-to-Noise Ratio (CNR) were measured at various FOVs and slice thicknesses with a body array coil. High spatial resolution was provided at less than 25 cm in FOV, and narrow phantom under 1 mm in diameter was obscured at more than 30 cm in FOV. Highest CNR was provided at 3 mm slice thickness on a 1.5 T unit, and at 4 mm slice thickness on a 1.0 T unit. Narrow phantom under 1 mm in diameter was depicted clearly on a 1.5 T unit, but irregularly on a 1.0 T unit. Taking required spatial resolution and CNR into consideration, we should determine optimal FOV and slice thickness for the assessment of anatomic details on MRCP.