Hangeshashinto-Associated Mesenteric Phlebosclerosis and Highly Atypical Adenoma Requiring Laparoscopic Right Hemicolectomy

Mesenteric phlebosclerosis is a rare ischemic colonic disorder caused by impaired venous drainage. Its prevalence is higher in East Asia, where herbal medicine is widely used. Treatment remains controversial. A 76-year-old woman who had taken Hangeshashinto, an herbal medicine, for 11 years was admitted for endoscopic treatment of high-grade dysplasia in the ascending colon. She had diarrhea and mesenteric phlebosclerosis diagnosed by abdominal computed tomography at age 71. At age 75, small polyps were detected in the ascending colon. A subsequent study revealed an increase in polyp size to 15 mm. Endoscopic mucosal resection failed to remove the lesion. A biopsy showed high-grade dysplasia with possible colon cancer risk. Conservative therapy did not improve mesenteric phlebosclerosis-related diarrhea; therefore, a laparoscopic right hemicolectomy was performed. Intraoperatively, the cecum was adherent to the abdominal wall and the right ovary. The specimen showed high-grade dysplasia in the mucosa and severe submucosal fibrosis. No metastasis was observed. This case shows the link between mesenteric phlebosclerosis and high-grade dysplasia in the ascending colon. Endoscopic mucosal resection was unsuccessful in removing the tumor. Endoscopic submucosal dissection was an alternative, but its safety in mesenteric phlebosclerosis-affected colonic segments remains uncertain. A laparoscopic right hemicolectomy was performed.

Elevated plasma and bile levels of corisin, a microbiota-derived proapoptotic peptide, in patients with severe acute cholangitis

BACKGROUND

Acute cholangitis is a severe, life-threatening infection of the biliary system that requires early diagnosis and treatment. The Tokyo Guidelines recommend a combination of clinical, laboratory, and imaging findings for diagnosis and severity assessment, but there are still challenges in identifying severe cases that need immediate intervention. The microbiota and its derived products have been implicated in the pathogenesis of acute cholangitis. Corisin is a microbiome-derived peptide that induces cell apoptosis, acute tissue injury, and inflammation. This study aimed to evaluate the potential of plasma and bile corisin as a biomarker of acute cholangitis.

METHODS

Forty patients with acute cholangitis associated with choledocholithiasis or malignant disease were enrolled. Nine patients without acute cholangitis were used as controls. Corisin was measured by enzyme immunoassays in plasma and bile samples. Patients were classified into severe and non-severe groups. The associations of plasma and bile corisin with the clinical grade of acute cholangitis and other parameters were analyzed by univariate and multivariate regression analysis.

RESULTS

Plasma and bile corisin levels were significantly higher in patients with acute cholangitis than in controls. Patients with severe acute cholangitis had significantly higher plasma and bile corisin levels than those with non-severe form of the disease. Bile corisin level was significantly correlated with markers of inflammation, coagulation, fibrinolysis, and renal function. Univariate analysis revealed a significant association of bile corisin but a weak association of plasma corisin with the clinical grade of acute cholangitis. In contrast, multivariate analysis showed a significant relationship between plasma corisin level and the disease clinical grade. The receiver operating characteristic curve analysis showed low sensitivity but high specificity for plasma and bile corisin to detect the severity of acute cholangitis. The plasma and bile corisin sensitivity was increased when serum C-reactive protein level was included in the receiver operating characteristic curve analysis.

CONCLUSIONS

Overall, these findings suggest that plasma and bile corisin levels may be useful biomarkers for diagnosing and monitoring acute cholangitis and that corisin may play a role in the pathophysiology of the disease by modulating inflammatory, coagulation and renal pathways.

Acute Calculous Cholecystitis Caused by Streptococcus gallolyticus subspecies pasteurianus: A Case Report

Acute cholecystitis is an infectious disease of the gallbladder caused mainly by Escherichia coli, Klebsiella, and Enterococcus species. Streptococcus gallolyticus subsp. pasteurianus, previously known as Streptococcus bovis biotype II/2, rarely causes endocarditis, meningitis, and septicemia, mainly in children. Biliary tract infections by Streptococcus gallolyticus subsp. pasteurianus are extremely rare. There have been no reports of cases in Japan. Here, we describe the first case in Japan of acute calculous cholecystitis caused by Streptococcus gallolyticus subsp. pasteurianus infection. A 63-year-old man was admitted to our hospital with epigastric pain and vomiting. He had moderate tenderness and a full sensation in the epigastrium. Abdominal imaging revealed multiple stones in the gallbladder. After admission, he had a high fever that did not improve with antibiotics. Percutaneous transhepatic gallbladder drainage was performed. The patient underwent open cholecystectomy. During surgery, several small stones in the gallbladder and an abscess were observed at the gallbladder base. Streptococcus gallolyticus subsp. pasteurianus was detected by bacterial culture of the bile juice. The gallstones were bilirubin calcium stones. The endoscopic study showed three adenomas in the colon, but the histopathological examination demonstrated no malignant cells. Although infection by this bacterium may not be rare, this is the first reported case in Japan of acute calculous cholecystitis caused by Streptococcus gallolyticus subsp. pasteurianus infection.

Acute necrotizing calculous cholecystitis after treatment with ceftriaxone in an elderly patient: a case report

BACKGROUND

Ceftriaxone, a third-generation cephalosporin antibiotic with a long plasma half-life, is widely used to treat various infections. The use of ceftriaxone can sometimes induce biliary sludge or stone formation. Although most cases of ceftriaxone-induced pseudolithiasis are asymptomatic or mild and resolve with discontinuation of the drug, we experienced an elderly case of severe acute necrotizing calculous cholecystitis after administration of ceftriaxone.

CASE PRESENTATION

A 72-year-old male patient was admitted to our hospital because of acute diverticulitis in ascending colon. Ceftriaxone was administered at a dose of 2 g/day for 6 days. Although he recovered after therapy, he was readmitted about 2 weeks later because of severe pain with rebound tenderness in the right upper quadrant. An abdominal imaging study revealed stones and sludge in the gallbladder that were not observed before starting ceftriaxone therapy. Therefore, antibiotic treatment with flomoxef 2 g/day was indicated. However, on the fifth day of readmission, the peritoneal irritation symptoms in the right upper quadrant worsened, and elevated inflammatory response and liver dysfunction were observed. Cholecystectomy was performed based on these findings. The resected inflamed gallbladder showed acute necrotizing cholecystitis with sand granular gallstones. A comparative analysis of the infrared spectroscopic pattern of the composition of gallstones collected during surgery with that of the ceftriaxone powder revealed that both have very similar infrared spectroscopic patterns.

CONCLUSIONS

Ceftriaxone-related pseudolithiasis is generally reversible and mainly observed in children. Here, we report a rare case of ceftriaxone-related acute necrotizing cholecystitis in an elderly patient. We confirmed that the stones in the gallbladder are composed of ceftriaxone. The older age, dehydration, fasting, and long-time bed rest during the administration of high-dose ceftriaxone were the potential risk factors for gallstone formation.

In silico assessment of gene function involved in cysteine biosynthesis in Arabidopsis: expression analysis of multiple isoforms of serine acetyltransferase

In plants, the inorganic sulfur is first fixed into cysteine by the cysteine biosynthetic pathway. This biosynthetic pathway of cysteine involves several enzymatic reactions. In Arabidopsis thaliana, multiple isoforms seem to participate in each enzymatic step for cysteine biosynthesis. To obtain more insights on the specific role of each isoform involved in the cysteine biosynthesis, in silico analysis of these isoforms using Arabidopsis expressed sequence tags (EST) database was carried out. This EST database analysis revealed distinct population distribution of ESTs among multiple isoforms, suggesting that each isoform has its particular expression pattern, presumably associated with its specific role in cysteine biosynthesis. As another in silico analysis, co-expression analysis of genes involved in sulfur metabolism in Arabidopsis was performed using a public transcriptome database of DNA microarrays. This co-expression analysis also suggested specific function and co-regulation of some isoform genes for cysteine biosynthesis by consideration on the clustering of co-expressed genes. From the results of sensitivity to feedback regulation, subcellular localization and expression of mRNA analyses, each serine acetyltransferase (SATase) isoform seems to have its specific role for cysteine biosynthesis. Similar expression patterns were observed between the experimental results of expression data for SATase isoforms and the in silico results of "digital northern" analysis using EST database.

Molecular and biochemical analysis of serine acetyltransferase and cysteine synthase towards sulfur metabolic engineering in plants

Serine acetyltransferase (SATase) and cysteine synthase (O-acetylserine (thiol)-lyase) (CSase) are committed in the final step of cysteine biosynthesis. Six cDNA clones encoding SATase have been isolated from several plants, e.g. watermelon, spinach, Chinese chive and Arabidopsis thaliana. Feedback-inhibition pattern and subcellular localization of plant SATases were evaluated. Two types of SATase that differ in their sensitivity to the feedback inhibition by L-cysteine were found in plants. In Arabidopsis, cytosolic SATase was inhibited by L-cysteine at a physiological concentration in an allosteric manner, but the plastidic and mitochondrial forms were not subjected to this feedback regulation. These results suggest that the regulation of cysteine biosynthesis through feedback inhibition may differ depending on the subcellular compartment. The allosteric domain responsible for L-cysteine inhibition was characterized, using several SATase mutants. The single change of amino acid residue, glycine-277 to cysteine, in the C-terminal region of watermelon SATase caused a significant decrease of the feedback-inhibition sensitivity of watermelon SATase. We made the transgenic Arabidopsis overexpressing point-mutated watermelon SATase gene whose product was not inhibited by L-cysteine. The contents of OAS, cysteine, and glutathione in transgenic Arabidopsis were significantly increased as compared to the wild-type Arabidopsis. Transgenic tobacco (Nicotiana tabacum) (F1) plants with enhanced CSase activities both in the cytosol and in the chloroplasts were generated by cross-fertilization of two transgenic tobacco expressing either cytosolic CSase or chloroplastic CSase. Upon fumigation with 0.1 microLL(-1) sulfur dioxide, both the cysteine and glutathione contents in leaves of F1 plants were increased significantly, but not in leaves of non-transformed control plants. These results indicated that both SATase and CSase play important roles in cysteine biosynthesis and its regulation in plants.

Cysteine synthase overexpression in tobacco confers tolerance to sulfur-containing environmental pollutants

Cysteine (Cys) synthase [O-acetyl-L-Ser(thiol)-lyase, EC 4.2.99.8; CSase] is responsible for the final step in biosynthesis of Cys. Transgenic tobacco (Nicotiana tabacum; F(1)) plants with enhanced CSase activities in the cytosol and in the chloroplasts were generated by cross-fertilization of two transformants expressing cytosolic CSase or chloroplastic CSase. The F(1) transgenic plants were highly tolerant to toxic sulfur dioxide and sulfite. Upon fumigation with 0.1 microL L(-1) sulfur dioxide, the Cys and glutathione contents in leaves of F(1) plants were increased significantly, but not in leaves of non-transformed control plants. Furthermore, the leaves of F(1) plants exhibited the increased resistance to paraquat, a herbicide generating active oxygen species.

Serine acetyltransferase involved in cysteine biosynthesis from spinach: molecular cloning, characterization and expression analysis of cDNA encoding a plastidic isoform

A cDNA clone that encodes a chloroplast-localizing isoform of serine acetyltransferase (SATase) (EC 2.3.1.30) was isolated from spinach (Spinacia oleracea L.). The cDNA encodes a polypeptide of 347 amino acids containing a putative transit peptide of ca. 60-70 amino acids at the N-terminal. Deduced amino acid sequence of SATase from spinach exhibited homology with other SATases from plants. DNA blot hybridization analysis showed the presence of 2-3 copies of Sat gene in the genome of spinach. RNA blot hybridization analysis indicated the constitutive expression of Sat gene in green and etiolated seedlings of spinach. Bacterial expression of the cDNA could directly rescue the cysteine auxotrophy of Escherchia coli caused by a lack of SATase locus (cysE). Catalytically active SATase protein was produced in E. coli cells. L-Cysteine, an end product of the cysteine biosynthetic pathway, inhibited the activity of recombinant spinach SATase, indicating the regulatory function of SATase in this metabolic pathway. A chloroplastic localization of this spinach SATase was revealed by the analyses of transgenic plant expressing transit peptide of SATase-beta-glucuronidase (GUS) fusion protein, and transient expression using the transit peptide-green fluorescent protein (GFP) fusion protein. The result from in vitro translation analysis suggests that this cDNA may encode both plastidic and cytosolic SATases.

Geranylgeranyl diphosphate synthase from Scoparia dulcis and Croton sublyratus. Plastid localization and conversion to a farnesyl diphosphate synthase by mutagenesis

cDNAs encoding geranylgeranyl diphosphate synthase (GGPPS) of two diterpene-producing plants, Scoparia dulcis and Croton sublyratus, have been isolated using the homology-based polymerase chain reaction (PCR) method. Both clones contained highly conserved aspartate-rich motifs (DDXX(XX)D) and their N-terminal residues exhibited the characteristics of chloroplast targeting sequence. When expressed in Escherichia coli, both the full-length and truncated proteins in which the putative targeting sequence was deleted catalyzed the condensation of farnesyl diphosphate and isopentenyl diphosphate to produce geranylgeranyl diphosphate (GGPP). The structural factors determining the product length in plant GGPPSs were investigated by constructing S. dulcis GGPPS mutants on the basis of sequence comparison with the first aspartate-rich motif (FARM) of plant farnesyl diphosphate synthase. The result indicated that in plant GGPPSs small amino acids, Met and Ser, at the fourth and fifth positions before FARM and Pro and Cys insertion in FARM play essential roles in determination of product length. Further, when a chimeric gene comprised of the putative transit peptide of the S. dulcis GGPPS gene and a green fluorescent protein was introduced into Arabidopsis leaves by particle gun bombardment, the chimeric protein was localized in chloroplasts, indicating that the cloned S. dulcis GGPPS is a chloroplast protein.

Molecular cloning and functional characterization of cDNAs encoding cysteine synthase and serine acetyltransferase that may be responsible for high cellular cysteine content in Allium tuberosum

The plants belonging to the genus Allium are known to accumulate sulfur-containing secondary compounds that are derived from cysteine. Here, we report on molecular cloning and functional characterization of two cDNAs that encode serine acetyltransferase and cysteine synthase from A. tuberosum (Chinese chive). The cDNA for serine acetyltransferase encodes an open reading frame of 289 amino acids, of which expression could complement the lacking of cysE gene for endogenous serine acetyltransferase in Escherichia coli. The cDNA for cysteine synthase encodes an open reading frame of 325 amino acids, of which expression in the E. coli lacking endogenous cysteine synthase genes could functionally rescue the growth without addition of cysteine. Both deduced proteins seem to be localized in cytosol, judging from their primary structures. Northern blot analysis indicated that both transcripts accumulated in almost equal levels in leaves and root of green and etiolated seedlings of A. tuberosum. The activity of recombinant serine acetyltransferase produced from the cDNA was inhibited by L-cysteine, which is the end-product of the pathway; however, the sensitivity to cysteine (48.7 microM of the concentration for 50% inhibition, IC(50)) was fairly low compared with that of previously reported serine acetyltransferases ( approximately 5 microM IC(50)) from various plants. In A. tuberosum, the cellular content of cysteine was several-fold higher than those in Arabidopsis thaliana and tobacco. This higher concentration of cysteine in A. tuberosum is likely due to the lower sensitivity of feedback inhibition of serine acetyltransferase to cysteine.

beta-Cyanoalanine synthase is a mitochondrial cysteine synthase-like protein in spinach and Arabidopsis

beta-Cyano-alanine synthase (CAS; EC 4.4.1.9) plays an important role in cyanide metabolism in plants. Although the enzymatic activity of beta-cyano-Ala synthase has been detected in a variety of plants, no cDNA or gene has been identified so far. We hypothesized that the mitochondrial cysteine synthase (CS; EC 4.2.99. 8) isoform, Bsas3, could actually be identical to CAS in spinach (Spinacia oleracea) and Arabidopsis. An Arabidopsis expressed sequence tag database was searched for putative Bsas3 homologs and four new CS-like isoforms, ARAth;Bsas1;1, ARAth;Bsas3;1, ARAth;Bsas4;1, and ARAth;Bsas4;2, were identified in the process. ARAth;Bsas3;1 protein was homologous to the mitochondrial SPIol;Bsas3;1 isoform from spinach, whereas ARAth;Bsas4;1 and ARAth;Bsas4;2 proteins defined a new class within the CS-like proteins family. In contrast to spinach SPIol;Bsas1;1 and SPIol;Bsas2;1 recombinant proteins, spinach SPIol;Bsas3;1 and Arabidopsis ARAth;Bsas3;1 recombinant proteins exhibited preferred substrate specificities for the CAS reaction rather than for the CS reaction, which identified these Bsas3 isoforms as CAS. Immunoblot studies supported this conclusion. This is the first report of the identification of CAS synthase-encoding cDNAs in a living organism. A new nomenclature for CS-like proteins in plants is also proposed.

Telomerase activity significantly correlates with chromosome alterations, cell differentiation, and proliferation in lung adenocarcinomas

Telomerase activity was examined by the telomeric repeat amplification protocol assay in 25 cases of lung adenocarcinoma, in relation to cancer cell differentiation, proliferation, and chromosome alterations. Telomerase activity, chromosome alterations, and cell proliferation assessed by Ki-67 labeling were significantly lower (P < .001 to .05) in well-differentiated (10 cases) than in moderately differentiated (8 cases) or poorly differentiated (7 cases) lesions. Telomerase activity by semiquantitative analysis with scoring of 0 to 3 was significantly correlated with similarly graded chromosome alterations (P < .05) and Ki-67 labeling indices (P < .002). Telomerase activity and chromosome alteration (T-C) indices generated by multiplication of telomerase activity and chromosome alteration scores also showed a significant correlation with cell differentiation. The Clara cell subtype, confirmed by electron microscopic analysis, significantly predominated in the well-differentiated group, showing a low grade of telomerase activity and chromosome alterations and low Ki-67 labeling indices, suggesting clinical relevance. No significant association of telomerase activity was found with p53 protein accumulation or Bcl-2 protein expression. The good correlation of telomerase activity with chromosome alterations, cell differentiation, and Ki-67 labeling indices suggests that this parameter might have potential application in estimation of prognosis.

[A case of complete regression of liver metastases by treatment with Futraful supposition]

The patient was a 57-year-old man abnormalities indicated in examinations by X-ray and ultrasonography in February, 1991. X-ray and endoscopic examination revealed a Borrmann type 3 carcinoma in the posterior wall and lesser curvature of the upper body of the stomach. The liver was swollen to 3 fingerbreadths on the right mid-clavicular line. Multiple liver metastases were revealed by computed tomography (CT). Proximal gastrectomy was done. From March 24, 1991, a Futraful suppository (1,500 mg/day) was given daily. After 4 months, CT showed the reduction and partial disappearance of the low-density areas of the liver. After 2 years and 7 months, CT showed very small low-density areas, which completely disappeared by April, 1998. The patient has had a good quality of life. According to the General Rules for Gastric Cancer Study, the patient belongs to the class of complete response.

Determination of the sites required for the allosteric inhibition of serine acetyltransferase by L-cysteine in plants

Serine acetyltransferase (SATase; EC 2.3.1.30) catalyzes the formation of O-acetylserine from L-Ser and acetyl-CoA in plants and bacteria. In plants, two types of SATase have been described. One is allosterically inhibited by L-Cys, and the second is not sensitive to L-Cys inhibition. However, the allosteric site in SATase has not been identified. To understand better the mechanism of L-Cys inhibition of plant SATases, we constructed several chimeric SATase enzymes from watermelon SATase (WaSATase) (sensitive type) and Arabidopsis SAT-p (insensitive type). These enzymes were expressed in Escherichia coli, and inhibition of the mutated SATase activity by L-Cys was analyzed. Mutated WaSATase, in which Met280 was changed to Ile, was no longer inhibited by L-Cys. Analysis of the inhibition the chimeric enzymes indicated that the C-terminal region of WaSATase from Pro276 to Phe285, in which five amino acids are different from those of SAT-p, was responsible for the determination of the sensitivity to L-Cys. In particular, Gly277 in the C-terminal region of WaSATase was primarily responsible for the L-Cys inhibition. The N-terminal half of the protein, which does not contain the catalytic domain, was also important for the sensitivity to L-Cys. These results indicate that the sensitivity of SATase to L-Cys is due to the N-terminal and C-terminal regions rather than to the catalytic domain.

Overproduction of L-cysteine and L-cystine by expression of genes for feedback inhibition-insensitive serine acetyltransferase from Arabidopsis thaliana in Escherichia coli

Two cDNAs encoding feedback inhibition-insensitive serine acetyltransferases of Arabidopsis thaliana were expressed in the chromosomal serine acetyltransferase-deficient and L-cysteine non-utilizing Escherichia coli strain JM39-8. The transformants produced 1600 to 1700 mg l(-1) of L-cysteine and L-cystine from glucose. The amount of these amino acids produced per cell was 30 to 60% higher than that of an E. coli strain carrying mutant serine acetyltransferase less sensitive to feedback inhibition.

Plastidic pathway of serine biosynthesis. Molecular cloning and expression of 3-phosphoserine phosphatase from Arabidopsis thaliana

In plants, Ser is biosynthesized by two different pathways: a photorespiratory pathway via Gly and a plastidic pathway via the phosphorylated metabolites from 3-phosphoglycerate. In contrast to the better characterization of the photorespiratory pathway at a molecular level, the molecular regulation and significance of the plastidic pathway are not yet well understood. An Arabidopsis thaliana cDNA encoding 3-phosphoserine phosphatase, the enzyme that is responsible for the conversion of 3-phosphoserine to Ser in the final step of the plastidic pathway of Ser biosynthesis, was cloned by functional complementation of an Escherichia coli serB- mutant. The 1.1-kilobase pair full-length cDNA, encoding 295 amino acids in its open reading frame, contains a putative organelle targeting presequence. Chloroplastic targeting has been demonstrated by particle gun bombardment using an N-terminal 60-amino acid green fluorescence protein fusion protein. Southern hybridization suggested the existence of a single-copy gene that mapped to chromosome 1. 3-Phosphoserine phosphatase enzyme activity was detected in vitro in the overexpressed protein in E. coli. Northern analysis revealed preferential gene expression in leaf and root tissues of light-grown plants with an approximately 1.5-fold abundance in the root compared with the leaf tissues. This indicates the possible role of the plastidic pathway in supplying Ser to non-photosynthetic tissues, in contrast to the function of the photorespiratory pathway in photosynthetic tissues. This work completes the molecular cloning and characterization of the three genes involved in the plastidic pathway of Ser biosynthesis in higher plants.

Cerebral blood flow in patients with normal pressure hydrocephalus

Mean cerebral blood flow (CBF) of the whole brain was measured in 48 patients who underwent cerebrospinal fluid shunt surgery for normal pressure hydrocephalus (NPH) by performing first-pass radionuclide angiography using 99Tcm-hexamethylpropylene amine oxime. Patients were divided according to outcome into an 'excellent' improvement group, a 'good' improvement group, a 'fair' improvement group and a 'poor' improvement group. Patients with excellent and good improvement had a preoperative mean CBF of 40.4 +/- 3.9 ml.100 g-1.min-1 and 37.1 +/- 5.5 ml.100 g-1.min-1, respectively, both of which were significantly (P < 0.005) higher than that in 11 patients who showed fair improvement (30.8 +/- 3.2 ml.100 g-1.min-1) and six patients who showed poor improvement (31.8 +/- 2.5 ml.100 g-1.min-1). Patients with a clinical improvement after shunting had an increased postoperative mean CBF. We conclude that patients with a preoperative mean CBF of over 35 ml.100 g-1.min-1 can show favourable improvement after a shunting procedure, and that the preoperative mean CBF of 32 ml.100 g-1.min-1 can be considered the critical level for treatment.

Regulation of serine biosynthesis in Arabidopsis. Crucial role of plastidic 3-phosphoglycerate dehydrogenase in non-photosynthetic tissues

In plants, Ser is synthesized through a couple of pathways. 3-Phosphoglycerate dehydrogenase (PGDH), the first enzyme that is involved in the phosphorylated pathway of Ser biosynthesis, is responsible for the oxidation of 3-phosphoglycerate to phosphohydroxypyruvate. Here we report the first molecular cloning and characterization of PGDH from Arabidopsis thaliana. Sequence analysis of cDNA and a genomic clone revealed that the PGDH gene is composed of three exons, encoding a 623-amino acid polypeptide (66, 453 Da). The deduced protein, containing three of the most conserved regions in the NAD-dependent 2-hydroxyacid dehydrogenase family, has 38-39% identity to its animal and bacterial counterparts. The presence of an N-terminal signal sequence for translocation into plastids was confirmed by particle-gun bombardment experiments using green fluorescence protein as a reporter protein for subcellular localization. Southern hybridization analysis and restriction fragment length polymorphism mapping indicated that PGDH is a single-copy gene that is mapped to the upper arm of chromosome 1. Northern hybridization analysis indicated preferential expression of PGDH mRNA in root tissues of light-grown plants, suggesting that the phosphorylated pathway of Ser biosynthesis plays an important role in supplying Ser to non-photosynthetic tissues. The recombinant enzyme overproduced in Escherichia coli displayed hyperbolic kinetics with respect to 3-phosphoglycerate and NAD+.

Isoform-dependent differences in feedback regulation and subcellular localization of serine acetyltransferase involved in cysteine biosynthesis from Arabidopsis thaliana

Serine acetyltransferase (SATase; EC 2.3.1.30), which catalyzes the formation of O-acetyl-L-serine (OAS) from acetyl-CoA and L-serine, plays a regulatory role in the biosynthesis of cysteine by its property of feedback inhibition by cysteine in bacteria and certain plants. Three cDNA clones encoding SATase isoforms (SAT-c, SAT-p, and SAT-m) have been isolated from Arabidopsis thaliana. However, the significance of the feedback regulation has not yet been clear in these different isoforms of SATase from A. thaliana. We constructed the overexpression vectors for cDNAs encoding three SATase isoforms of A. thaliana and analyzed the inhibition of SATase activity by cysteine using the recombinant SATase proteins. In the case of SAT-c, the activity was feedback-inhibited by a low concentration of cysteine (the concentration that inhibits 50% activity; IC50 = 1.8 microM). By contrast, SAT-p and SAT-m were feedback inhibition-insensitive isozymes. We also determined the subcellular localization of three SATase isozymes by the transient expression of fusion proteins of each SATase N-terminal region with jellyfish green fluorescent protein (GFP) in 4-week-old Arabidopsis leaves. The SAT-c-GFP fusion protein was stayed in cytosol, whereas SAT-p-GFP and SAT-m-GFP fusion proteins were localized in chloroplasts and in mitochondria, respectively. These results suggest that these three SATase isoforms, which are localized in the different organelles, are subjected to different feedback regulation, presumably so as to play the particular roles for the production of OAS and cysteine in Arabidopsis cells. Regulatory circuit of cysteine biosynthesis in the plant cells is discussed.

Molecular cloning and characterization of the genes encoding two isoforms of cysteine synthase in the enteric protozoan parasite Entamoeba histolytica

The enteric protozoan parasite Entamoeba histolytica was shown to possess cysteine synthase (CS) activity. The cDNA and genomic clones that encode two isoforms of the E. histolytica CS were isolated and characterized from a clonal strain of E. histolytica by genetic complementation of the cysteine-auxotrophic Escherichia coli NK3 with an E. histolytica cDNA library. The two types of the E. histolytica CS genes differed from each other by three nucleotides, two of which resulted in amino acid substitution. Deduced amino acid sequences of the E. histolytica CS, with a calculated molecular mass of 36721 Da and an isoelectric point of 6.39, exhibited 38-48% identity with CS of bacterial and plant origins. The absence of the amino-terminal transit peptide in the deduced protein sequences and the presence of the CS protein mainly in the supernatant fraction of the amoebic lysate after cellular fractionation suggested that the identified E. histolytica CS genes encoded cytosolic isoforms. Substrate specificity of the recombinant E. histolytica CS was similar to that of plant CS. Phylogenetic analysis indicates that the amoebic CS, first described in Protozoa, does not belong to any families of the CS superfamily, and represents a new family.

Molecular characterization of plastidic phosphoserine aminotransferase in serine biosynthesis from Arabidopsis

Serine biosynthesis in plants proceeds by two pathways; a photorespiratory pathway which is associated with photorespiration and a pathway from phosphoglycerate. A cDNA encoding plastidic phosphoserine aminotransferase (PSAT) which catalyzes the formation of phosphoserine from phosphohydroxypyruvate has been isolated from Arabidopsis thaliana. Genomic DNA blot analysis indicated that this enzyme is most probably encoded by a single gene and is mapped on the lower arm of chromosome 4. The deduced protein contains an N-terminal extension exhibiting the general features of a plastidic transit peptide, which was confirmed by subcellular organelle localization using GFP (green flourescence protein). Northern analysis indicated preferential expression of PSAT in roots of light-grown plants, supporting the idea that the phosphorylated pathway may play an important role in supplying the serine requirement of plants in non-green tissues. In situ hybridization analysis of PSAT revealed that the gene is generally expressed in all types of cells with a significantly higher amount in the meristem tissue of root tips.

Cerebral blood flow measurement in patients with impaired consciousness: usefulness of 99mTc-HMPAO single-photon emission tomography in clinical practice

The relationship between impairment of consciousness and quantitative cerebral blood flow (CBF) was investigated. The mean CBF of the whole brain was measured by the Patlak-plot method using technetium-99m hexamethylpropylene amine oxime single-photon emission tomography (99mTc-HMPAO SPET) in patients with the following diseases: cerebral infarction, intraparenchymal haemorrhage, subarachnoid haemorrhage, brain tumour and cerebral contusion. The clinical symptoms were evaluated according to the severity of impaired consciousness, aphasia and dementia. Four hundred and eighty-five CBF measurements were performed. Patients with alert consciousness showed an age-related decline in mean CBF. Patients with aphasia showed a significant reduction in mean CBF compared with those without aphasia. Impaired consciousness was proportional to reduction in mean CBF regardless of types of pathology, and the size of lesion did not influence the mean CBF. Patients with dementia showed a significant reduction in mean CBF proportional to the severity of dementia. The quantitative measurement of CBF using 99mTc-HMPAO SPET is reliable in clinical evaluations.

[A new operative technique of posttraumatic syringomyelia: thecoperitoneal shunt]

The authors report a successful case of operative treatment for a patient with a traumatic syringomyelia. A 33-year-old male presented with arm pain and right sided sensory loss due to posttraumatic syringomyelia. Magnetic resonance image showed syringomyelia from the upper cervical cord to the lower thoracic cord. Based on the hypothesis of Ball and Dayan, and Williams, a thecoperitoneal shunt operation was performed. The proximal shunt catheter was placed in the subarachnoid space rostral to the injury level and the distal shunt catheter was introduced percutaneously into the peritoneum. Postoperative radiological studies showed improvement and progressive clinical deterioration stopped. The advantages of this surgery are that it is less invasive to the spinal cord, and that there is a lower shunt malfunction rate because of the use of a D-L catheter which develops less shunt obstruction. Furthermore, we were able to evaluate shunt flow from the valve. In spite of multicystic syrinx, we were easily able to determine the placement of the shunt catheter for this operation. For these reasons, the thecoperitoneal shunt can be placed before further expansion of the syrinx. We think that this method is safer for patients with incomplete cord injury than S-P shunt or S-S shunt.

Cationic cholesterol with a hydroxyethylamino head group promotes significantly liposome-mediated gene transfection

A novel cationic cholesterol derivative with a hydroxyethylamino head group, cholesteryl-3beta-carboxyamidoethylene-N-hydroxyethylamine (II), has been synthesized and used for liposome-mediated gene transfection. The cationic liposomes containing the derivative (II) facilitated greatly pSV2CAT gene transfection into mouse NIH3T3 and L929 cells in the absence of serum. The transfection efficiency was much higher than those by the cationic liposomes containing cationic derivatives with a dialkylamino head group (I, III or IV). Further, the efficiency by the cationic liposomes with the derivative (II) was not so much decreased in the presence of serum. This suggested that a novel cationic cholesterol derivative (II) should be very promising in liposome-mediated gene transfection of plasmid and antisense DNA into target cells.

Genomic structure and expression analyses of serine acetyltransferase gene in Citrullus vulgaris (watermelon)

The genomic clones of Sat gene encoding serine acetyltransferase (SATase), a key enzyme in cysteine biosynthesis in plants, were isolated from the genomic library of Citrullus vulgaris (watermelon). The determination of nucleotide sequence of 5.7 kilobase pair (kbp) length revealed the presence of two introns of 1939 basepair (bp) and 515 bp length in the gene. The transcription start point was determined by primer extension experiments. Southern blot analysis indicated the presence of a single copy of the Sat gene and a couple of additional related sequences in the genome of C. vulgaris. The expression of Sat was analyzed in watermelon plants growth under sulfur- and/or nitrogen-starved conditions and in the presence of pyrazole, O-acetylserine and N-acetylserine. Only slight increment (ca. 1.5-2-fold) of Sat gene expression was observed upon sulfur starvation for 48 h. Interestingly, the addition of pyrazole, which is a precursor of beta-pyrazolealanine (beta-PA) synthesized by SATase and cysteine/beta-PA synthase, enhanced the expression of Sat by ca. 2-fold.

Production of plant non-protein amino acids by recombinant enzymes of sequential biosynthetic reactions in bacteria

We constructed the co-expression vector, pFK4, in which two cDNAs encoding serine acetyltransferase (SATase) and beta-(pyrazol-1-yl)-L-alanine/L-cysteine synthase (beta-PA/CSase) from Citrullus vulgaris (watermelon) were over-expressed under the transcriptional control of T7 promoter in Escherichia coli. Accumulation of both SATase and beta-PA/CSase in soluble extracts of E. coli was confirmed by immunoblotting. The high enzymatic activities of SATase and L-cysteine synthase (CSase) were detected in cell-free extracts of E. coli carrying pFK4. The activities of the formation of beta-PA and L-mimosine, plant non-protein amino acids, from O-acetyl-L-serine (OAS) and the precursor heterocyclic compounds, pyrazole and 3,4-dihydroxypyridine, were also found in the extracts. beta-PA was also produced in vivo from L-serine and pyrazole as precursors by E. coli cells transformed with pFK4. beta-PA was accumulated mainly in the extra-cellular culture medium. The pronounced accumulation of L-cysteine and L-methionine was observed in the cells transformed with pFK4. Additionally, we also constructed vectors which carried chimeric genes encoding fusion proteins of SATase and beta-PA/CSase. However, the fusion proteins tended to form insoluble inclusion bodies and thus to exhibit only weak enzymatic activities. The successful results of pFK4 shows the way to create a new sequential biosynthetic pathway of plant specific amino acids in bacterial cells by means of recombinant DNA technology.

Molecular cloning, characterization and expression of cDNA encoding phosphoserine aminotransferase involved in phosphorylated pathway of serine biosynthesis from spinach

Phosphoserine aminotransferase (PSA) catalyzes the conversion of phosphohydroxypyruvate to phosphoserine in the phosphorylated pathway of serine biosynthesis. A cDNA clone encoding PSA was isolated from the cDNA library of spinach (Spinacia oleracea L.) green leaves. Determination of the nucleotide sequence revealed the presence of an open reading frame encoding 430 amino acids, exhibiting 38-50% homology with the amino acid sequences of bacterial, yeast and animal PSA. It contains an N-terminal extension of ca. 60 amino acids in addition to the sequences from other organisms. The general features of plastidic transit peptide are observed in this N-terminal sequence, suggesting the plastid localization of the PSA protein encoded by this cDNA. The bacterial expression of the cDNA could functionally rescue the auxotrophy of serine in the serC- mutant, Escherichia coli KL282. The enzymatic activity of PSA was demonstrated in vitro in the extracts of E. coli over-expressing the cDNA. Southern blot analysis indicated the presence of a couple of related genes (Psa) in the spinach genome. RNA blot hybridization suggested the preferential expression of the Psa gene in the roots of green seedlings and in the suspension cells cultured under a dark condition.

A transcriptional activation domain of ATMYB2, a drought-inducible Arabidopsis Myb-related protein

Trans-activation activity of ATMYB2, a drought-inducible Myb-related protein in Arabidopsis thaliana, was analyzed using a transient assay of Arabidopsis leaf protoplasts. ATMYB2 activated the transcription of a reporter gene from the MYB-binding site in a sequence-specific manner. Deletion of the C-terminal region of ATMYB2 reduced the trans-activation of the reporter gene, indicating that the acidic region at the C-terminus of ATMYB2 is required for transcriptional activation. The domain exchange analysis with the yeast GAL4 revealed that the C-terminal acidic region of ATMYB2 contains a sufficient domain for trans-activation. These results indicate that ATMYB2 acts as a transcriptional activator and that the C-terminal acidic region of ATMYB2 can function as a transcriptional activation domain.

Effect of zeta potential of cationic liposomes containing cationic cholesterol derivatives on gene transfection

Cationic liposomes are known to be useful tools for gene transfection. However, the relation between transfection efficiency and physicochemical properties of liposomes has not been well understood. Here, we synthesized eight cationic derivatives of cholesterol which contain a tertiary amino head group with a different spacer arm. Transfection of plasmid pSV2CAT DNA into cells was done by cationic liposomes made of a mixture of dioleoylphosphatidylethanolamine (DOPE) and each cationic cholesterol derivative. At the same time we measured zeta potential of cationic liposomes by laser Doppler spectroscopy. The present results indicated that zeta potentials of cationic liposomes were well related to transfection activity of pSV2CAT DNA. This suggested that zeta potential of cationic liposomes is one of important factors which control gene transfection.

Isolation and characterization of a cDNA encoding a sulfate transporter from Arabidopsis thaliana

A cDNA encoding a sulfate transporter was isolated from Arabidopsis thaliana. The isolated clone contained an open reading frame encoding a polypeptide of 658 amino acids, exhibiting the highest similarity (62%) with the sequence of the low-affinity sulfate transporter of a tropical legume Stylosanthes hamata. Northern blot analysis indicated the constitutive accumulation of a 2.6 kb length transcript in leaves and roots of seedlings. We also propose that A. thaliana contains three sulfate transporter genes which are expressed as 3.0, 2.7 and 2.6 kb length transcripts, respectively, in an organ-specific manner.

An orally active antitumor cyclohexanediamine-Pt(IV) complex: trans,cis,cis-bis(n-valerato)(oxalato)(1R,2R-cyclohexane diamine)Pt(IV)

In order to develop orally active antitumor platinum complexes, several cyclohexanediamine-Pt(IV) complexes of a general formula trans,cis,cis-[Pt(IV) (OCOCnHn+1)2 (oxalato)(1R,2R-cyclohexanediamine)] were synthesized by derivatizing oxaliplatin [Pt(II)(oxalato)(1R,2R-cyclohexanediamine), I-OHP], which is a potent antitumor cyclohexanediamine-Pt(II) complex we have prepared and now undergoing clinical trials. The I-OHP derivatives were found to be stable, lipophilic and reduced to yield I-OHP, an active species, quantitatively by ascorbate in vitro. All the derivatives were antitumor active against mouse lymphocytic leukemia L1210 when given i.p. In particular, trans-bis-valerato-oxalato-1R,2R-dach-Pt(IV), C5-OHP, showed markedly high activity. C5-OHP also exhibited significant antitumor activity against L1210 when orally administered. C5-OHP was considered to be a suitable candidate for the oral cancer chemotherapy agent to be developed.

Calcium signals in helper T cells after interaction with antigen-specific and antigen-nonspecific B cells

By confocal fluorescence microscopy we have studied the rises of the intracellular free calcium ion concentration ([Ca2+]i) in helper T cells (KLH-specific, I-Ak-restricted Th1 cells, 28-4) after interaction with antigen-specific and antigen-nonspecific B cells (antigen-presenting cells). Antigen-specific and antigen-nonspecific B cells were prepared by the preincubation of TNP (trinitrophenol)-specific B cell hybridomas (TP67.21 I-Ak) with TNP-conjugated KLH and KLH alone, respectively. Calcium signals in Th1 cells (28-4) were induced by antigen-specific B cells one hundred times more efficiently as those by antigen-nonspecific B cells. Herbimycin A, a tyrosine kinase inhibitor, suppressed the former signals but not the latter. These results indicated that tyrosine phosphorylation was involved in the antigen processing of antigen-specific B cells but not in the processing of antigen-nonspecific B cells.

Molecular cloning and characterization of a plant serine acetyltransferase playing a regulatory role in cysteine biosynthesis from watermelon

Serine acetyltransferase (SATase; EC 2.3.1.30), which catalyzes the reaction connecting serine and cysteine/methionine metabolism, plays a regulatory role in cysteine biosynthesis in plants. We have isolated a cDNA clone encoding SATase by direct genetic complementation of a Cys- mutation in Escherichia coli using an expression library of Citrullus vulgaris (watermelon) cDNA. The cDNA encodes a polypeptide of 294 amino acids (31,536 Da) exhibiting 51% homology with that of E. coli SATase. DNA-blot analysis indicated the presence of a single copy of the SATase gene (sat) in watermelon. RNA hybridization analysis suggested the relatively ubiquitous and preferential expression in the hypocotyls of etiolated seedlings. Immunoblot analysis indicated the accumulation of SATase predominantly in etiolated plants. L-Cysteine, an end product of the cysteine biosynthetic pathway, inhibited the SATase in an allosteric manner, indicating the regulatory function of SATase in this metabolic pathway, whereas beta-(pyrazole-1-yl)-L-alanine, a secondary metabolite formed partly through the cysteine biosynthetic pathway, showed no inhibitory effect. A multi-enzyme complex was formed from recombinant proteins of SATase and cysteine synthase (O-acetylserine(thiol)-lyase) from watermelon, suggesting efficient metabolic channeling from serine to cysteine, preventing the diffusion of intermediary O-acetyl-L-serine.

[Multiple meningioma associated with intraosseous and tentorial meningioma--case report]

We report a case of multiple meningioma associated with intraosseous and tentorial meningioma. A 75-year-old woman was admitted to our hospital with blurred vision and exophthalmos in the left eye. Left lower hemianopsia, deterioration of visual acuity and right cerebellar signs were found on neurological examination. CT and MR image revealed an intraosseous tumor of the left sphenoid bone and a right tentorial mass. Cytogenetic analysis failed to reveal any abnormalities of chromosome 22. The intraosseous tumor which was transitional type meningioma and the tentorial mass, which was a fibroblastic meningioma were successfully excised. Postoperatively, the patient's symptoms and signs improved. Intraosseous meningioma associated with multiple meningioma is extremely rare and the histogenesis of meningioma arising from ectopic arachnoid cells is discussed.

Differentiation of malignant glioma and metastatic brain tumor by thallium-201 single photon emission computed tomography

The use of superdelayed thallium-201 single photon emission computed tomography (201Tl SPECT) for differentiating malignant gliomas from cerebral metastases was investigated in 23 patients (7 with meningioma, 6 with glioma, 7 with cerebral metastasis, 1 with each of neurinoma, abscess, and necrosis). 4 mCi of 201Tl was injected intravenously, and gamma camera scans were performed after 10 minutes and 4, 24, 72, and 96 hours (superdelayed scan). The mean thallium index of meningiomas was significantly higher than those of gliomas and cerebral metastases after 10 minutes, while the mean thallium indices of meningiomas and gliomas were significantly higher than those of cerebral metastases after 96 hours. The combination of early and superdelayed 201Tl SPECT may be useful in differentiating malignant gliomas from cerebral metastases.

Molecular cloning of a cysteine synthase cDNA from Citrullus vulgaris (watermelon) by genetic complementation in an Escherichia coli Cys- auxotroph

We have isolated cDNA clones encoding cysteine synthase (CSase, EC 4.2.99.8), which catalyzes the terminal step in cysteine biosynthesis, by direct genetic complementation of a Cys- mutation in Escherichia coli with an expression library of Citrullus vulgaris (watermelon) cDNA. The library was constructed from 8-day-old etiolated seedlings of C. vulgaris in the lambda ZAPII vector, converted to a plasmid library by in vivo excision, and then used for transformation of cysteine auxotroph E. coli NK3, which lacks the cysK and cysM loci. The complementing cDNA containing a 560 bp 5'-untranslated region encodes a polypeptide of 325 amino acids of M(r) 34342. The translational product reacted with an antibody raised against CSase A of Spinacia oleracea. CSase and beta-pyrazolealanine synthase activities were demonstrated in vitro in extracts from E. coli cells expressing the cDNA. Genomic DNA blot analysis indicated the presence of a single copy of the gene, designated cysA, in the C. vulgaris genome. RNA blot hybridization indicated constitutive expression of cysA in cotyledons, hypocotyls and radicles of green and etiolated seedlings. These data suggested that this cDNA clone encodes CSase A the homolog of which in spinach is localized in the cytoplasm. The molecular phylogenetic tree of the amino acid sequences of CSases from plants and bacteria suggested that there are three families in the CSase superfamily; the plant CSase A family, the plant CSase B family and the bacterial CSase family. The proteins in the plant CSase A family are the most conserved relative to the ancestral CSase protein.

Platinum and palladium complexes containing ethylenediamine derivatives as carrier ligands and their antitumor activity

We prepared new antitumor active platinum complexes containing N,N'-bis(2-chloroethyl)ethylenediamine (ClEn) as an alkylating carrier ligand in order to obtain increased antitumor effects. Some of the platinum complexes synthesized showed enhanced antitumor activity. However, palladium(II) complexes containing ClEn were inactive against L1210 and P388.

Results of combined resection of invaded organs in patients with potentially curable, advanced gastric cancer

OBJECTIVE

To assess the role of combined resection of neighbouring organs that have been invaded by cancer in patients with potentially curable, but advanced, gastric cancer.

DESIGN

Retrospective follow up study.

SETTING

University department of surgery.

SUBJECTS

204 patients (from a consecutive series of 745 who had had gastric resection for cancer) all of whom had undergone potentially curative operations for advanced disease: 91 had had combined resection of other invaded organs.

RESULTS

Five year survival was 65% for 113 patients who had gastrectomy alone and 46% for 91 patients who also had other affected organs resected (p < 0.02).

CONCLUSION

We recommend resection of all organs that have been invaded by cancer, provided that there is no evidence such as widespread nodal involvement, peritoneal dissemination, or extensive hepatic metastases, that would make cure impossible.

Evidence for identity of beta-pyrazolealanine synthase with cysteine synthase in watermelon: formation of beta-pyrazole-alanine by cloned cysteine synthase in vitro and in vivo

The responsibility of cysteine synthase (EC 4.2.99.8) from watermelon (Citrullus vulgaris) for the formation of beta-(pyrazole-1-yl)-L-alanine, a non-protein amino acid specifically accumulated in Curcubitaceae plants, was confirmed in vitro and in vivo by the cloned cDNA on expression vectors, pCCS11 and pCEN1. The cDNA sequence derived from pCCS11, an expression vector driven by the lacZ promoter, was placed under the transcriptional control of strong T7 promoter of pET3d to yield an over-expression vector, pCEN1, in Escherichia coli. The concentration of the exogenous cysteine synthase protein was increased up to approximately 10% of the total soluble protein of E. coli cells by the expression of cDNA on pCEN1. beta-(Pyrazole-1-yl)-L-alanine was formed in vitro from O-acetyl-L-serine and pyrazole by the action of cysteine synthase expressed in E. coli carrying pCCS11 or pCEN1. To confirm the responsibility of cysteine synthase for the formation of beta-(pyrazole-1-yl)-L-alanine in vivo, the feeding experiments of pyrazole and serine or O-acetyl-L-serine were carried out using the transformed E. coli culture. beta-(Pyrazole-1-yl)-L-alanine was produced in vivo by feeding the substrates to the culture of E. coli carrying pCEN1. These results provide the confirming evidence that the cloned cysteine synthase of watermelon catalyzes the formation of beta-(pyrazole-1-yl)-L-alanine, indicating that beta-pyrazolealanine synthase is identical with cysteine synthase in Cucurbitaceae plants.

Cytotoxicity of platinum(IV) and platinum(II) complexes containing 1R,2R-cyclohexanediamine as a ligand

Several Pt(IV) and Pt(II) complexes containing 1R,2R-cyclohexanediamine (1R,2R-dach) as a carrier ligand were synthesized. The cytotoxicities and the uptake of the platinum complexes by leukemia L1210 cells were compared in order to study the correlation between their structures and cytotoxicities. [Pt(II)Cl2(1R,2R-dach)], [(Pt(II)(oxalato)(1R,2R-dach)], and [Pt(II)(malonato)(1R,2R-dach)], which have excellent anticancer properties, exhibited very high cytotoxicities and were easily taken up by leukemia L1210 cells. [Pt(IV)Cl4(1R,2R-dach)], trans(Cl)-[Pt(IV)Cl2(oxalato)(1R,2R-dach)], and trans(Cl)-[Pt(IV)Cl2(malonato)(1R,2R-dach)] also had high cytotoxicities. After a short incubation time, the uptake of [Pt(II)Cl2(1R,2R-dach)], [Pt(II)(oxalato)(1R,2R-dach)], and [Pt(II)(malonato)(1R,2R-dach)] by leukemia L1210 cells were respectively very similar to those of [Pt(IV)Cl4(1R,2R-dach)], trans(Cl)-[Pt(IV)Cl2(oxalato)(1R,2R-dach)], and trans(Cl)-[Pt(IV)Cl2(malonato)(1R,2R-dach)]. In addition, trans(OH)-[Pt(IV)(OH)2Y2(1R,2R-dach)] (Y2: oxalato or malonato) did not exhibit cytotoxicity towards leukemia L1210 cells, whereas trans(Cl)-[Pt(IV)Cl2Y2(1R,2R-dach)] (Y2: oxalato or malonato) were highly cytotoxic. The accumulation of trans(OH)-[Pt(IV)(OH)2Y2(1R,2R-dach)] in leukemia L1210 cells was much lower than that of trans(Cl)-[Pt(IV)Cl2Y2(1R,2R-dach)]. Platinum(IV) complexes, in which leaving groups are replaced by hydroxide groups, have decreased cytotoxic activity, because the hydroxide groups of the platinum(IV) complex reduce the uptake of platinum by the cells. trans(OH),cis(Cl)-[Pt(IV)(OH)2Cl2(1R,2R-dach)], which has hydroxide and chloride groups, was easily incorporated into the cells and exhibited the high cytotoxic activity. This behavior indicates that the chloride group apparently overcomes the ameliorating effect of the hydroxide group.

Antibodies for fluorescent molecular rotors

We have prepared monoclonal antibodies for the fluorescent molecular rotors 9-(2-carboxy-2-cyanovinyl)julolidine (CCVJ) and 9-(dicyanovinyl)julolidine (DCVJ). Mouse monoclonal antibody (IgG2b) prepared against CCVJ-conjugated bovine serum albumin strongly bound CCVJ and DCVJ. The CCVJ (or DCVJ) binding to IgG and Fab was accompanied by a drastic increase in fluorescence quantum yield, suggesting the restriction of intramolecular rotational relaxation about the donor-acceptor bond of the fluorophores. Nonspecific IgG never changed the quantum yield of the fluorophores. From the Scatchard plots, the association constants of CCVJ to IgG and Fab were 6.8 x 10(7) and 5.4 x 10(7) M-1, respectively, and the numbers of moles of CCVJ bound per mole of IgG and Fab were calculated to be 2.0 (+/- 0.1) and 1.0 (+/- 0.05), respectively. The fluorescence spectra of the IgG-bound CCVJ were quite similar to those of Fab-bound CCVJ. The fluorescence lifetimes of the IgG-bound and Fab-bound CCVJ were 388 and 383 ps at 25 degrees C, respectively. They were 6.3 times as long as the fluorescence lifetime of CCVJ free in solution (62 ps). These results indicated that the drastic increases in quantum yields were due to the decreases of the nonradiative rate constants of the antibody-bound CCVJ, as well as due to the changes of the intrinsic radiative rate constant, and that the nonradiative internal rotations about the donor-acceptor bond of CCVJ were not dependent on the size of the bound antibody molecules.(ABSTRACT TRUNCATED AT 250 WORDS)

Single cell observation of ligand-induced desensitization of B-cell membrane immunoglobulin-mediated calcium signals

Using a digital imaging fluorescence microscope we have observed the membrane immunoglobulin (mIg)-induced desensitization of calcium signals in individual BAL17 B lymphoma cells which express two kinds of antigen receptors, mIgM and mIgD. The mIgD-mediated desensitization was partly abrogated by pretreating the cells with phorbol 12-myristate 13-acetate (PMA) for 24 h, however, the mIgM-mediated one was not affected by the pretreatment. This supports the idea that at least two mechanisms are operative for mIg-induced desensitization in B cells.

A fluorescent molecular rotor probes the kinetic process of degranulation of mast cells

A confocal fluorescence microscope was used to study the exocytotic secretory processes of mast cells in combination with an fluorescent molecular rotor, 9-(dicyanovinyl)julolidine (DCVJ). DCVJ is known to be an unique fluorescent dye which increases its quantum yield with decreasing intramolecular rotation. Here, DCVJ-loaded peritoneal rat mast cells were stimulated with compound 48/80 and their fluorescence images were compared with fluorescence calcium images of fluo-3-loaded mast cells. Subsequent to transient increases in intracellular free calcium ion concentration, DCVJ fluorescence increased dramatically in the cytoplasm and formed a ring-like structure around the nucleus, suggesting the possibility that the dye bound to the proteins composing the cytoskeletal architecture. Furthermore, the increases of DCVJ fluorescence intensities were mostly blocked in the presence of cytochalasin D (10 microM). However, fluo-3 fluorescence intensities still increased after addition of compound 48/80.