[Regulation of osmolyte transporter gene expression by tonicity]

In response to exposure to hypertonic environment, cells accumulate small organic solutes termed osmolytes that protect them from the adverse effects of hypertonicity. Some osmolytes (myo-inositol, betaine and taurine) are accumulated by specific transporters. Those transporters have been cloned by expression cloning techniques. Transcription of osmolyte transporters is induced by hypertonicity. In situ hybridization reveals the localization of the Na+/myo-inositol cotransporter and the betaine transporter (BGT1) mRNAs in the kidney. The BGT1 gene was cloned and its 5' flanking region has been characterized A 13 bp tonicity responsive enhancer (TONE) has been identified. Analysis of transgenic mice harboring a 5' flanking region of the BGT1 gene, that included TONE, showed that it provides inducible reporter expression in kidney medulla.

Molecular genetic analysis of variant phenotypes of the ABO blood group system

ABO is clinically the most important blood group system in transfusion medicine and includes many variant phenotypes. To understand the molecular genetic basis of this polymorphic system, we have analyzed genomic DNAs obtained from Japanese individuals possessing variant ABO phenotypes including A2, Ax, Ael, cis-AB, Bx, and Bel. By polymerase chain reaction-single-strand conformation polymorphism (SSCP) and nucleotide sequence analyses, we identified 11 different alleles. These alleles had nucleotide sequences different from those of the previously described 13 different alleles responsible for the common ABO phenotypes. Analysis of the nucleotide sequences of the alleles responsible for those variant phenotypes showed that the amino acid residues at position 266 and 268 may be crucial for transferase specificity, whereas those at positions 214, 216, 223, 291, and 352 may be critical for the activity level. Nine of the 11 alleles, responsible for the A2, Ax, Ael, cis-AB, Bx, and Bel phenotypes, were presumed to be generated from common ABO alleles by single nucleotide mutations such as nonsynonymous substitution, deletion, or insertion. Two other alleles, responsible for the A2 and Ael phenotypes, may have originated by recombination, gene conversionlike events or accumulation of nucleotide substitutions. Our data indicate that different alleles could cause the same ABO variant phenotypes, and that these alleles do not necessarily belong to a single evolutionary lineage.

Expression of betaine transporter mRNA: its unique localization and rapid regulation in rat kidney

Betaine is a major compatible osmolyte in the renal medulla. It is taken up into cells via the betaine gamma-amino-n-butyric acid transporter (BGT-1). We investigated the localization of BGT-1 mRNA and its acute regulation by NaCl and furosemide administration. In situ hybridization revealed that BGT-1 mRNA is predominantly present in the outer medulla and papilla. Less intense signals were seen in the inner medulla and no signals were found in the cortex. Microscopic examination suggested that intense signals were present in the medullary thick ascending limbs of Henle's loop (MTAL) and the inner medullary collecting ducts (IMCD). A reverse transcription and polymerase chain reaction assay of individual microdissected segments along the nephron confirmed its localization. Intraperitoneal administration of NaCl rapidly increased the signal in the MTAL, and furosemide prevented the increase in BGT-1 mRNA by NaCl loading. In contrast, BGT-1 mRNA in the IMCD is less sensitive to these kinds of acute regulation. These results suggest that BGT-1 expression in the MTAL is rapidly regulated in response to the magnitude of NaCl absorption, as suggested for the expression of Na+/myo-inositol cotransporter.

[Tizanidine for preanesthetic medication]

The effect of tizanidine given as a premedication on perioperative hemodynamics (mean blood pressure, heart rate), sedation, hypnosis and midazolam requirements for induction were assessed in 68 patients scheduled for elective surgery under general anesthesia. Patients were assigned to three groups. Group 1 was premedicated 90 min prior to induction with tizanidine 4 mg po (n = 28); group 2 was premedicated with tizanidine 2 mg po (n = 12); group 3 received no premedication (n = 28). In group 1, increase of mean blood pressure on anesthesia induction was attenuated significantly and sedative and hypnotic effects were stronger significantly compared with other groups. We also found that the amounts of midazolam necessary for loss of consciousness were significantly less in patients who had received tizanidine 4 mg. In conclusion, tizanidine is a useful drug as preanesthetic medication for general anesthesia.

Inhibition of TGF-beta 1 expression by antisense oligonucleotides suppressed extracellular matrix accumulation in experimental glomerulonephritis

Overproduction of transforming growth factor-beta 1 (TGF-beta 1) has been implicated in the pathogenesis of fibrotic diseases. TGF-beta 1 plays a crucial role in the accumulation of extracellular matrix (ECM) in human and experimental glomerular diseases. However, it remains unclear whether inhibition of TGF-beta 1 overproduction would suppress TGF-beta 1-induced ECM accumulation. To inhibit the overproduction of TGF-beta 1 in experimental glomerulonephritis induced by anti-Thy 1.1 antibody, we introduced antisense oligodeoxynucleotides (ODN) for TGF-beta 1 into the nephritic kidney by the HVJ-liposome-mediated gene transfer method. Sense, scrambled or reverse ODN were also introduced as controls. Transfected ODN accumulated mainly in the nuclei of mesangial cells in the glomeruli of transfected kidneys. In the antisense ODN-transfected rats, a marked decrease in expression of TGF-beta 1 mRNA was confirmed by Northern analysis. Consequently, the expression of TGF-beta 1 protein in the glomerulus was markedly reduced in the antisense ODN-transfected kidney with a comparable effect in preventing glomerular ECM expansion in experimental glomerulonephritis. In contrast, sense, scrambled and reverse ODNs failed to suppress TGF-beta 1 expression and ECM accumulation. Thus, these results suggested that inhibition of TGF-beta 1 overproduction could suppress progression to glomerulosclerosis.

The construction of novel mobilizable YAC plasmids and their behavior during trans-kingdom conjugation between bacteria and yeasts

Trans-kingdom conjugation is an easy and efficient method for gene transfer from prokaryotes to eukaryotes since it does not require DNA extraction and purification. We constructed novel mobilizable plasmids pAY-YAC-B and pAY-YAC-E. The origin of conjugal transfer (oriT) was inserted at two different positions, pAY-YAC-B contains oriT region in between two telomeres whereas pAY-YAC-E has oriT at the cloning site of pYAC4. By conjugation, both plasmids were successfully transferred from E. coli to S. cerevisiae and S. kluyveri yeasts with the aid of helper plasmid pRH220 which harbors mob and tra genes. The plasmids were transferred more efficiently in S. cerevisiae compared to S. kluyveri. The analyses by restriction enzyme digestion and Southern hybridization indicated that both plasmids maintained their original structure and size in transconjugant yeasts, therefore, reflecting the faithful nicking and subsequent resealing of plasmids during conjugation. The comparison between conjugative transfer and transformation has also been performed and discussed.

Extensive polymorphism of ABO blood group gene: three major lineages of the alleles for the common ABO phenotypes

Polymorphism of the ABO blood group gene was investigated in 262 healthy Japanese donors by a polymerase chain reactions-single-strand conformation polymorphism (PCR-SSCP) method, and 13 different alleles were identified. The number of alleles identified in each group was 4 for A1 (provisionally called ABO*A101, *A102, *A103 and *A104 according to the guidelines for human gene nomenclature), 3 for B (ABO*B101, *B102 and *B103), and 6 for O (ABO*O101, *O102, *O103, *O201, *O202 and *O203). Nucleotide sequences of the amplified fragments with different SSCP patterns were determined by direct sequencing. Phylogenetic network analysis revealed that these alleles could be classified into three major lineages, *A/*O1, *B and *O2. In Japanese, *A102 and *B101 were the predominant alleles with frequencies of 83% and 97% in each group, respectively, whereas in group O, two common alleles, *O101 (43%) and *O201 (53%), were observed. These results may be useful for the establishment of ABO genotyping, and these newly described ABO alleles would be advantageous indicators for population studies.

Alternative splicing of the pyruvate kinase M gene in a minigene system

The M1-type and M2-type isozymes of pyruvate kinase are produced from a single gene by mutually exclusive use of exons 9 and 10. Selection of exon 10 generates the M2 type, which occurs in most tissues, whereas the M1 type is expressed by use of exon 9 only in skeletal muscle, heart and brain. We investigated the mechanism by which exon 10, but not exon 9 is selected in M2-expressing cells by transfecting minigenes containing exon 9 and/or exon 10 in cells and by analyzing the transcripts using reverse-transcriptase polymerase chain reaction. Deletion of the most conserved region in intron 8 did not affect selection of exon 10 in dRLh-84 cells, which express only the M2 type. Exclusion of exon 10 from the minigene resulted in two major spliced products. One included correctly spliced exon 9 and the other skipped this exon. Similar splicing patterns were observed when these minigenes were transfected in hepatocytes which express the L type, but not M1 or M2 types. The 5' splice site but not the 3' splice site of exon 9 was found to be hardly recognized by the splicing machinery in dRLh-84 cells. Mutation of the 5' splice site sequence of exon 9 to that of exon 10 and vice versa did not change the splicing patterns. However, mutation of this site of exon 9 to a perfectly complementary sequence of U1 snRNA resulted in selection of exon 9 correctly spliced to exon 10. A 9-10 fusion exon (constructed by substitution of 68 bases of the 3' portion of exon 9 and 33 bases of the 5' portion of intron 9 for the corresponding regions of exon 10 and intron 10) was also correctly incorporated into a major product together with exon 10. Thus, we propose that exon 9 is not recognized in non M1-expressing cells due to the weak signal of its 5' splice site and that, although the 5' splicing signal of exon 10 also appears to be weak, this exon can be recognized in these cells because the 5' recognition signal may be relatively strengthened by cis-acting element(s) which may be present in the 3' portion of exon 9 and the 5' portion of intron 9 and/or the corresponding regions of exon 10 and intron 10.

High affinity IgE receptor-mediated prostaglandin E2 production by monocytes in atopic dermatitis

High affinity IgE receptor (Fc epsilon R I) expression on monocytes and its upregulation on monocytes from patients with atopic dermatitis (AD) have been recently reported. In this study, we investigated whether prostaglandin E2 (PGE2) release from AD monocytes was Fc epsilon R I-dependent or not. The monocytes were stimulated with anti-Fc epsilon R I monoclonal antibody (mAb) and anti-Fc epsilon R II mAb. Cross-linking of Fc epsilon R I, but not that of Fc epsilon R II induced PGE2 release from monocytes. In order to confirm that the PGE2 release is IgE-dependent, stimulation with IgE+anti-IgE, IgG+anti-IgG and immune complexes made by incubation with AD patients' serum and recombinant Der fII (rDer fII-IC) were carried out in the culture. Significant PGE2 release by all the stimulants was observed, as compared with spontaneous release. PGE2 release by immune complex made by incubation with IgE-absorbed AD serum and rDer fII was much lower than that by rDer fII-IC. In monocytes from nonatopic donors, significant PGE2 release was observed when stimulated with IgE+anti-IgE, IgG+anti-IgG, rDer fII-IC, but not with anti-FC epsilon R I mAb and anti-Fc epsilon R II mAb. However, the release were significantly lower than respective PGE2 releases from AD monocytes. Taken together, cross-linking of Fc epsilon R I and IgE induced a PGE2 release from monocytes. This is a first report demonstrating an Fc epsilon R I-dependent mediator release from monocytes of AD patients.

The canine betaine gamma-amino-n-butyric acid transporter gene: diverse mRNA isoforms are regulated by hypertonicity and are expressed in a tissue-specific manner

The Na(+)- and Cl(-)-coupled betaine transporter, designated BGT1, a member of the neurotransmitter transporter gene family, is responsible for accumulation of betaine in hypertonic Madin-Darby canine kidney (MDCK) cells and presumably in the hypertonic renal medulla. The canine gene for the betaine gamma-amino-n-butyric acid transporter has been cloned and analyzed. The gene extends over 28 kb and consists of 18 exons. The 5' end of the gene has three alternative first exons (1A, 1B, and 1C+D). Analysis of BGT1 mRNA revealed that there is considerable divergence in the 5' untranslated sequence resulting from three different 5' end motifs (A, B, and C) followed by an alternative motif (D) as well as two internal acceptor sites for splicing. Eight kinds of BGT1 mRNA were classified into three types (A, B, and C) according to the 5' end sequence. Northern blot analysis using probes specific for the A, B, or C motif revealed that hypertonicity induces all three types in MDCK cells. Reverse transcription and polymerase chain reaction showed that each type was expressed in a tissue-specific manner. Primer extension and/or RNase protection assays as well as transfection assays into MDCK cells demonstrated that exons 1A, 1B, and 1C+D have independent transcription initiation sites under control of independent promoters. Diverse mRNA isoforms are regulated by hypertonicity and are expressed in a tissue-specific manner.

High affinity IgE receptor (Fc epsilon RI) expression on eosinophils infiltrating the lesions and mite patch tested sites in atopic dermatitis

Expression of the high affinity IgE receptor (Fc epsilon RI) on eosinophils has recently been reported. This led us to evaluate Fc epsilon RI expression on eosinophils in atopic dermatitis (AD). Double immunofluorescence stainings with an anti-Fc epsilon RI monoclonal antibody (mAb) and a polyclonal antieosinophil cationic protein (ECP) antibody were performed on lesional biopsy specimens from patients with AD and from patients with bullous pemphigoid (BP) as controls. In AD and BP lesions, 77% and 70% of eosinophils expressed Fc epsilon RI, respectively. However, the intensity of Fc epsilon RI staining in AD was much stronger than in BP, suggesting upregulation of Fc epsilon RI expression on eosinophils in AD. In addition, the eosinophils infiltrating AD lesions were stained strongly with anti-CD23 mAb and anti-IgE antibody. At the sites of mite patch testing in AD, Fc epsilon RI-, CD23- and IgE-positive eosinophils were observed to the same degree as in the lesions, and a considerable number of mite antigen-bearing eosinophils were detected. Fc epsilon RI and CD23 were both upregulated on the skin-infiltrating eosinophils in AD and bound IgE molecules.

The tonicity-sensitive element that mediates increased transcription of the betaine transporter gene in response to hypertonic stress

BGT1, the Na(+)-and Cl- coupled betaine transporter, is responsible for the accumulation of high concentrations of the non-perturbing osmolyte betaine in hypertonic Madin-Darby canine kidney (MDCK) cells and presumably in the hypertonic renal medulla. In MDCK cells, the increase in activity of the betaine transporter is preceded by an increase in transcription of BGT1 and in the abundance of BGT1 mRNA. To investigate the molecular mechanism of transcriptional regulation by tonicity, we have characterized the 5'-flanking region of the gene. Transient transfection assays in MDCK cells cultured in isotonic or hypertonic medium using luciferase reporter constructs containing various fragments of the 5'-flanking region revealed that the region spanning base pairs -69 to -50 5' to the transcription initiation site (-69/-50) has hypertonicity-responsive enhancer activity. A double-stranded -69/-50 concatemer cloned 5' to an SV40 basal promoter and luciferase reporter gene in hypertonic cells exhibited more than 11-fold the activity in isotonic cells. Expression assays and electrophoretic mobility shift assays of mutants of -69/-50 identified a smaller region that is required for hypertonicity to induce increased expression and a slowly migrating band on mobility shift assays.

cDNA cloning of a cytosolic protein tyrosine phosphatase (RKPTP) from rat kidney

A rat cDNA encoding a non-receptor type phosphotyrosine phosphatase (PTPase; EC 3.1.3.48) was identified. The 1608 bp cDNA contains a single open reading frame that predicts a 382 amino acid protein with M(r) 44,438. The predicted protein has no apparent signal or transmembrane sequences, suggesting that it is a cytosolic protein. The C-terminal region has a PTPase catalytic domain that has 40-50% nucleic acid homology to other known PTPases. The N-terminal region has little amino acid sequence homology to any other known sequences. The recombinant protein of the cloned cDNA expressed in Escherichia coli was shown to possess PTPase activity using myelin basic protein, tyrosine phosphorylated by p43v-abl tyrosine kinase, as a substrate.

[The effect of assisted hatching on patients repeatedly failed to conceive by in vitro fertilization]

Assisted hatching (AHA) techniques were used in 67 patients who had repeatedly failed to achieve conception by conventional IVF-ET in spite of replacement by good quality embryos. The age of the female patients ranged from 28 to 44 years and the causes of their infertility included tubal factors (n = 33), male infertility (16), endometriosis (8) and unexplained causes (21). Zona drilling with acid Tyrode's solution was performed on 248 embryos in 88 cycles approximately 72 hours after oocyte collection. One to 4 embryos were transferred to the uterus 1 to 4 hours later. Twenty-four clinical pregnancies were established (27.3%) and the implantation rate was 15.3% (38/248). These results were both significantly higher than those for our conventional IVF-ET (22.0% pregnancy rate and 10.7% implantation rate) (p < 0.05). Eleven babies have been born normally and there are 16 current pregnancies. These preliminary findings suggest that AHA might be beneficial for patients in whom conventional IVF-ET had repeatedly failed.

Morphological traits of crania in modern Kyongsangnam-do Koreans

The crania of modern Kyongsangnam-do or Southeastern Koreans were examined metrically and nonmetrically. In comparison with those of several modern samples from the northeastern Asia, the modern Kyongsangnam-do crania are characterized by their brachycranic and high cranial vaults as well as their high facial skeletons with the flat frontal and zygomaxillary regions. The modern Kyongsangnam-do shows a close affinity to the modern Central Koreans in the analyses of metric and nonmetric cranial traits. In the same Kyongsangnam-do, the cranial vaults are higher and shorter, and the nasal bones are not flatter in the modern than in the Yean-ri (4th to 7th century A.D.) samples. However, both the modern and the Yean-ri have morphological cranial traits similar to Asian continental Mongoloid in terms of the large upper facial height, the flatness in the frontal and zygomaxillary regions, and the close relationship of Smith's MMD based on 22 nonmetric cranial traits. Thus, it is suggested that these cranial traits, which are common with those of the Asian continental Mongoloid, have been kept from the Yean-ri to the modern Koreans in Kyongsangnam-do.