Analysis of T cell receptor Vbeta diversity in peripheral CD4 and CD8 T lymphocytes in patients with autoimmune thyroid diseases

Autoimmune thyroid diseases are characterized by intrathyroidal infiltration of CD4(+) and CD8(+) T lymphocytes reactive to self-thyroid antigens. Early studies analysing T cell receptor (TCR) Valpha gene usage have shown oligoclonal expansion of intrathyroidal T lymphocytes but not peripheral blood T cells. However, TCR Vbeta diversity of the isolated CD4(+) and CD8(+) T cell compartments in the peripheral blood has not been characterized fully in these patients. We performed complementarity-determining region 3 (CDR3) spectratyping as well as flow cytometric analysis for the TCR Vbeta repertoire in peripheral CD4(+) and CD8(+) T cells from 13 patients with Graves' disease and 17 patients with Hashimoto's thyroiditis. Polyclonal TCR Vbeta repertoire was demonstrated by flow cytometry in both diseases. In contrast, CDR3 spectratyping showed significantly higher skewing of TCR Vbeta in peripheral CD8(+) T cells but not CD4(+) T cells among patients with Hashimoto's thyroiditis compared with healthy adults. We found trends towards a more skewed CDR3 size distribution in those patients having disease longer than 5 years and requiring thyroid hormone replacement. Patients with Graves' disease exhibited no skewing both in CD4(+) and CD8(+) T cells. These findings indicate that clonal expansion of CD8(+) T cells in Hashimoto's thyroiditis can be detected in peripheral blood and may support the role of CD8(+) T cells in cell-mediated autoimmune attacks on the thyroid gland in Hashimoto's thyroiditis.

Clonotypic analysis of T cell reconstitution after haematopoietic stem cell transplantation (HSCT) in patients with severe combined immunodeficiency

Haematopoietic stem cell transplantation (HSCT) is performed for treatment of a broad spectrum of illnesses. Reconstitution of an intact immune system is crucial after transplantation to avoid infectious complications, and above all, the establishment of T cell receptor (TCR) diversity is the most important goal in the procedure. Until recently, little has been known of the mechanism of T cell reconstitution in the very early period after HSCT. In this study, we analysed TCR repertoires sequentially in four patients with severe combined immunodeficiency (SCID) before and after HSCT. In all patients, the TCR repertoires were extremely abnormal before HSCT, whereas after transplantation there was progressive improvement in TCR diversity, based on analysis of the TCR Vbeta repertoire and CDR3 size distributions. Somewhat unexpectedly, there was a significant but transient expansion of TCR diversity 1 month after transplantation in all cases. Clonotypic analysis of TCRs performed in one case showed that many T cell clones shared identical CDR3 sequences at 1 month and that the shared fraction decreased progressively. These results indicate that early expansion of TCR diversity may reflect transient expansion of pre-existing mature T cells from the donor blood, independent of de novo T cell maturation through the thymus.

Effects of Coffee Consumption on Oxidative Susceptibility of Low-Density Lipoproteins and Serum Lipid Levels in Humans

Since little is known about how coffee intake affects low-density lipoprotein (LDL) oxidative susceptibility and serum lipid levels, we conducted an in vivo study in 11 healthy male students of Wakayama Medical University aged between 20 and 31 years fed an average Japanese diet. On days 1-7 of the study, the subjects drank mineral water. On day 7, the subjects began drinking coffee, 24 g total per day, for one week. This was followed by a one week "washout period" during which mineral water was consumed. Fasting peripheral venous blood samples were taken at the end of each one-week period. LDL oxidation lag time was approximately 8% greater (p < 0.01) after the coffee drinking period than the other periods. Serum levels of total cholesterol and LDL-cholesterol (LDL-C) and malondialdehyde (MDA) as thiobarbituric acid reactive substances (TBARS) were significantly decreased after the coffee drinking period. Finally, regular coffee ingestion may favorably affect cardiovascular risk status by modestly reducing LDL oxidation susceptibility and decreasing LDL-cholesterol and MDA levels.

Human glycosaminoglycan glucuronyltransferase I gene and a related processed pseudogene: genomic structure, chromosomal mapping and characterization

Here we describe the characterization of the human glycosaminoglycan glucuronyltransferase I gene (GlcAT-I) and a related pseudogene. The GlcAT-I gene was localized to human chromosome 11q12-q13 by in situ hybridization of metaphase chromosomes. GlcAT-I spanned 7 kb of human genomic DNA and was divided into five exons. Northern blot analysis showed that GlcAT-I exhibited ubiquitous but markedly different expressions in the human tissues examined. The GlcAT-I promoter was approx. 3-fold more active in a melanoma cell line than in a hepatoma cell line, providing evidence for the differential regulation of the gene's expression. Stepwise 5' deletions of the promoter identified a strong enhancer element between -303 and -153 bp that included binding motifs for Ets, CREB (cAMP-response-element-binding protein) and STAT (signal transducers and activators of transcription). Screening of a human genomic library identified one additional distinct genomic clone containing an approx. 1.4 kb sequence region that shared an overall 95.3% nucleotide identity with exons 1-5 of GlcAT-I. However, a lack of intron sequences, as well as the presence of several nucleotide mutations, insertions and deletions that disrupted the potential GlcAT-I reading frame, suggested that the clone contained a processed pseudogene. The pseudogene was localized to chromosome 3. The human genome therefore contains two related GlcAT-I genes that are located on separate chromosomes.

Regulation of CD40 function by its isoforms generated through alternative splicing

CD40 is a member of the tumor necrosis factor receptor superfamily. The interaction between CD40 and CD40 ligand (CD154) activates NF-kappa B, Jun N-terminal kinase, and Janus kinase/signal transducers and activators of transcription pathways and promotes B cell growth, differentiation, and survival as well as IL-12 production in macrophages and dendritic cells. We demonstrate here the existence of multiple isoforms of CD40 mRNA generated by alternative splicing and show that their expression is regulated differentially in activated macrophages and dendritic cells. Pre-CD40 RNA is spliced preferentially out to signal-transducible CD40 mRNA in the early stage of activation; half of the CD40 mRNA is replaced by the signal-nontransducible CD40 mRNAs in the later stages (24 h). Using IL-12 p40 gene expression as a reporter for CD40 signaling, we show that three of the alternative isoforms can disable signaling through CD40. The major alternative isoform lacks the membrane-associated endodomain and seems to reduce the amount of the signal-transducible form available on the cell surface. It would seem, therefore, that CD40 expression is controlled by posttranscriptional and posttranslational regulation through alternative splicing. Modulation of isoform expression may provide a mechanism by which cells regulate their susceptibility to CD40L signaling.

Directed differentiation of dendritic cells from mouse embryonic stem cells

Dendritic cells (DCs) are uniquely capable of presenting antigen to naive T cells, either eliciting immunity [1] or ensuring self-tolerance [2]. This property identifies DCs as potential candidates for enhancing responses to foreign [3] and tumour antigens [4], and as targets for immune intervention in the treatment of autoimmunity and allograft rejection [1]. Realisation of their therapeutic potential would be greatly facilitated by a fuller understanding of the function of DC-specific genes, a goal that has frequently proven elusive because of the paucity of stable lines of DCs that retain their unique properties, and the inherent resistance of primary DCs to genetic modification. Protocols for the genetic manipulation of embryonic stem (ES) cells are, by contrast, well established [5], as is their capacity to differentiate into a wide variety of cell types in vitro, including many of hematopoietic origin [6]. Here, we report the establishment, from mouse ES cells, of long-term cultures of immature DCs that share many characteristics with macrophages, but acquire, upon maturation, the allostimulatory capacity and surface phenotype of classical DCs, including expression of CD11c, major histocompatibility complex (MHC) class II and co-stimulatory molecules. This novel source should prove valuable for the generation of primary, untransformed DCs in which candidate genes have been overexpressed or functionally ablated, while providing insights into the earliest stages of DC ontogeny.

The EXT1/EXT2 tumor suppressors: catalytic activities and role in heparan sulfate biosynthesis

The D-glucuronyltransferase and N-acetyl-D-glucosaminyltransferase reactions in heparan sulfate biosynthesis have been associated with two genes, EXT1 and EXT2, which are also implicated in the inherited bone disorder, multiple exostoses. Since the cell systems used to express recombinant EXT proteins synthesize endogenous heparan sulfate, and the EXT proteins tend to associate, it has not been possible to define the functional roles of the individual protein species. We therefore expressed EXT1 and EXT2 in yeast, which does not synthesize heparan sulfate. The recombinant EXT1 and EXT2 were both found to catalyze both glycosyltransferase reactions in vitro. Coexpression of the two proteins, but not mixing of separately expressed recombinant EXT1 and EXT2, yields hetero-oligomeric complexes in yeast and mammalian cells, with augmented glycosyltransferase activities. This stimulation does not depend on the membrane-bound state of the proteins.

Posttranscriptional regulation of IL-10 gene expression through sequences in the 3'-untranslated region

IL-10 is an 18-kDa immunoregulatory cytokine the transcription of which is controlled by the ubiquitously expressed transcription factors Sp1 and Sp3. Although many cell types express IL-10 mRNA, not all make detectable amounts of protein, and levels of protein expression vary enormously. We show here that much of this variation can be accounted for by posttranscriptional mechanisms. Multiple copies of potential mRNA destabilizing motifs AUUUA and related sequences can be found to the 3'-untranslated region (UTR) of IL-10 mRNA distributed through three potential regulatory regions. Evidence of RNA-destabilizing activities in all three regions was deduced from luciferase reporter assays. The half-life of RNA containing the 3'-UTR of IL-10 mRNA was quite short in both nonstimulated (t1/2 = 1 h), and PMA-stimulated EL-4 cell (t1/2 = 3 h). In contrast, the half-life of RNA lacking the 3'-UTR was much longer (t1/2 = >12 h) whether cells were stimulated or not. This suggests that many cells are poised to secrete IL-10 and will do so if they receive appropriate posttranscriptional signals.

IL-10 gene expression is controlled by the transcription factors Sp1 and Sp3

IL-10 is an 18-kDa cytokine with a key role in homeostatic control of inflammatory and immune responses. We have investigated how transcription of the IL-10 gene is regulated, so as to be able to understand the circumstances of IL-10 expression in both health and disease. In the mouse, IL-10 gene expression is regulated by a TATA-type promoter with a critical cis-acting element containing GGA repeats located at -89 to -77. Its complementary sequence is similar to the cis-acting elements (TCC repeats) in the promoters of genes encoding epidermal growth factor receptor and CD58. All these elements comprise a common CCTCCT sequence with less conserved C + T-rich sequences. Eliminating this CCTCCT sequence results in a marked reduction in promoter activity, suggesting a necessary role in IL-10 gene expression. Despite its dissimilarity to the G + C-rich Sp1 consensus sequence (GC box), Sp1 and Sp3 transcription factors could be shown to bind to this motif. The requirement for Sp1 and Sp3 in transcription of IL-10 was confirmed using Drosophila SL2 cells, which lack endogenous Sp factors. These results suggest that the transcription of IL-10 is positively regulated by both Sp1 and Sp3.

Nob1p, a new essential protein, associates with the 26S proteasome of growing saccharomyces cerevisiae cells

Nob1p, which interacts with Nin1p/Rpn12, a subunit of the 19S regulatory particle (RP) of the yeast 26S proteasome, has been identified by two-hybrid screening. NOB1 was found to be an essential gene, encoding a protein of 459 amino acid residues. Nob1p was detected in growing cells but not in cells in the stationary phase. During the transition to the stationary phase, Nob1p was degraded, at least in part, by the 26S proteasome. Nob1p was found only in proteasomal fractions in a glycerol gradient centrifugation profile and immuno-coprecipitated with Rpt1, which is an ATPase component of the yeast proteasomes. These results suggest that association of Nob1p with the proteasomes is essential for the function of the proteasomes in growing cells.

Characterization of recombinant human glucuronyltransferase I involved in the biosynthesis of the glycosaminoglycan-protein linkage region of proteoglycans

We characterized the recombinant glucuronyltransferase I (GlcAT-I) involved in the glycosaminoglycan-protein linkage region biosynthesis. The enzyme showed strict specificity for Galbeta1-3Galbeta1-4Xyl, exhibiting negligible incorporation into other galactoside substrates including Galbeta1-3Galbeta1-O-benzyl, Galbeta1-4GlcNAc and Galbeta1-4Glc. A comparison of the GlcAT-I with another beta1,3-glucuronyltransferase involved in the HNK-1 epitope biosynthesis revealed that the two beta1,3-glucuronyltransferases exhibited distinct and no overlapping acceptor substrate specificities in vitro. Nevertheless, the transfection of the GlcAT-I cDNA into COS-1 cells induced the significant expression of the HNK-1 epitope. These results suggested that the high expression of the GlcAT-I gene rendered the cells capable of synthesizing the HNK-1 epitope.

Structure and chromosomal location of mouse and human CD52 genes

Human CD52 (CAMPATH-1 antigen) is an abundant surface molecule on lymphocytes and a favoured target for lymphoma therapy and immunosuppression. It comprises a small glycosylphosphatidylinositol (GPI) anchored peptide to which a large carbohydrate moiety is attached. Structurally similar proteins include the proposed mouse homologue, B7 antigen (B7-Ag; not to be confused with the CD28 ligand), and human and mouse CD24. Sequence similarities between CD52 and B7-Ag precursors are concentrated over the signal peptides and the sequences cleaved during GPI attachment. While the short mature peptides are not apparently homologous, the N-linked glycosylation site is retained in both. We describe similarities in exon-intron organisation, syntenic chromosome positions (human CD52, 1p36; mouse B7-Ag, chromosome 4, between Dsil and D4Nds16) and sequence homology in the promoter regions which strongly suggests that B7-Ag is the mouse homologue of CD52. The structure of these genes is also similar to that of mouse CD24, suggesting a common ancestor. Promoter activities and transcription start sites were also analysed. These results suggest that human CD52 and mouse B7-Ag gene expressions are controlled by TATA-less promoters.

Phosphotyrosine of macrophage by low-density lipoproteins from hemodialysis patients

BACKGROUND

Because of the possible importance of tyrosine phosphorylation in the signal transduction process, we investigated whether an interaction of low-density lipoprotein (LDL) from hemodialysis patients (HD-LDL) and human macrophages induces tyrosine-phosphorylated proteins in the macrophages.

METHODS

Human monocyte-derived macrophages were incubated with HD-LDL (100 micrograms/ml) or native LDL (100 micrograms/ml) for 15 minutes at 37 degrees C. Whole cells were lyzed with Tris-HCl buffer containing vanadate and Triton X-100. After centrifugation, lyzed proteins were divided into Triton-soluble and -insoluble fractions. Both fractions (soluble and insoluble) were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and were electroblotted onto a polyvinylidene difluoride (PVDF) membrane. Immunoblotting was performed using an antibody against phosphotyrosine or c-Src.

RESULTS

Several proteins in the range 40 to 100 kDa were found to be phosphorylated constitutively in the macrophages and not affected by the addition of HD-LDL. HD-LDL did not induce any tyrosine-phosphorylated proteins either in the soluble or insoluble fractions. Macrophages pretreated with tyrosine kinase inhibitor genestein drastically inhibited tyrosine phosphorylation of these proteins. The nonreceptor tyrosine kinase, c-Src p60, was also strongly tyrosine phosphorylated in the macrophages, and this was not enhanced by the stimulation of HD-LDL.

CONCLUSION

These data suggest that tyrosine autophosphorylated proteins may play a role in the early step of signal transduction in the macrophages.

Lysophosphatidylcholine up-regulates IL-1 beta-induced iNOS expression in rat mesangial cells

BACKGROUND

Nitric oxide (NO), a simple molecule synthesized from L-arginine by NO synthases (NOS), has been identified to play an important role in cell communication, cell defense and cell injury. Several studies have shown that glomeruli from rats with immune-mediated glomerular inflammation have increased production of NO. Recently, it was also reported that inducible NOS (iNOS) is localized in mesangial cells, glomerular epithelial cells and infiltrating cells in the diseased human glomeruli. On the other hand, while oxidized low density lipoprotein (ox-LDL) has been suggested to be related to progression of glomerular disease, the mechanism remains unknown. We investigated the effect of lysophosphatidylcholine (LPC), a modified phospholipid produced during LDL oxidation, on iNOS expression in rat mesangial cells.

METHODS AND RESULTS

Treatment of mesangial cells with interleukin-1 beta (IL-1 beta) induced iNOS activity measured as nitrite levels in cell culture supernatants. Treatment with LPC had no effect. In contrast, coincubation with LPC and IL-1 beta resulted in a markedly higher nitrite content compared to that after incubation with IL-1 beta alone. Western blot analysis revealed that LPC caused a significant increase in the formation of iNOS protein in the presence of IL-1 beta.

CONCLUSION

These findings suggest that LPC may contribute to progression of glomerular inflammation by augmenting IL-1 beta-induced iNOS expression.

Effect of simvastatin on the lipid profile of hemodialysis patients

BACKGROUND

Simvastatin, a 3-hydroxy 3-methylglutaryl co-enzyme A (HMG-CoA) reductase inhibitor, is used widely for treatment of hypercholesterolemia. Simvastatin may be a suitable treatment for dyslipidemia in hemodialysis (HD) patients. However, investigation of the side-effects and safety of long-term administration of simvastatin to HD patients has been limited. In this study, we investigated the effects and safety of simvastatin and its effects on lipoprotein metabolism in hypercholesterolemic patients on HD.

METHODS

Simvastatin was administered at a dosage of 5 mg/day for 24 weeks to 38 HD patients with high serum total cholesterol (TC) levels (200 mg/dl) or low high-density lipoprotein cholesterol (HDL-C) levels (35 mg/dl). Every four weeks, serum lipids, apolipoprotein, lipoprotein (a) [Lp(a)] and malondialdehyde (MDA) levels were measured. In addition, lipid levels were determined in each lipoprotein fraction separated by ultracentrifugation.

RESULTS

After 24 weeks of simvastatin administration, TC significantly decreased by 25.7%, and low-density lipoprotein cholesterol (LDL-C) was significantly decreased by 33.6%. Triglyceride (TG) and HDL-C showed no significant changes. Apolipoprotein (apo) B significantly decreased by 24.5% and apo E by 30.0%. No significant changes were observed in the other apolipoproteins. MDA was also significantly decreased, whereas Lp(a) was not significantly altered. In the lipoprotein fractions, very LDL cholesterol (VLDL-C), intermediate-density lipoprotein cholesterol (IDL-C), LDL1 cholesterol (LDL1-C), and LDL2 cholesterol (LDL2-C) showed significant decreases. No particular side-effects were observed during the 12 months of simvastatin administration.

CONCLUSIONS

These results suggest that simvastatin appears to be safe and effective in HD patients with hypercholesterolemia.

Ongoing clinical trials of lipid reduction therapy in patients with renal disease

BACKGROUND

Lipid abnormalities in renal disease are associated with both a progressive decline in renal function and cardiovascular complications. Whether or not lipid anomalies are causal is not yet clear. Experimental studies have demonstrated that potentially atherogenic lipoproteins, such as low density lipoproteins (LDL), are associated with renal pathophysiological changes that result in progressive glomerular and interstitial damage and an ultimate reduction in renal function. These findings indicate that hyperlipidemia accelerates glomerular and interstitial damage in renal disease. Clinical studies also show that renal function declines more rapidly among patients with primary renal disease or diabetic nephropathy who have hyperlipidemia. However, few reports have demonstrated the effect of hypolipidemic agents on the progression of renal function among patients with renal disease, and those renal patients who were treated with lipid-lowering agents have not been clinically studied under large-scale controlled conditions. In addition, although cardiovascular complications are the most important factors associated with mortality in dialysis patients, randomized, large-scale trials studying the relationship between therapeutic intervention by lipid-lowering agents and prevention of cardiovascular complications have not been implemented.

METHODS

We reviewed controlled and uncontrolled reported studies that examined the effects of lipid-lowering therapy in patients with renal disease.

RESULTS

Most studies showed that 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors reduce cholesterol-rich apolipoprotein (apo)B-containing lipoproteins with no effects on renal function or proteinuria among patients with progressive renal disease. Small uncontrolled studies show that simvastatin and probucol moderately reduce proteinuria among patients with membranous nephropathy. One small retrospective study showed that long-term vitamin E therapy reduces aortic calcification in dialysis patients.

CONCLUSIONS

Prospective, randomized large-scale trials including ongoing clinical trials of lipid reduction therapy and therapeutic interventions such as the use of the combination therapy with hypolipidemic agents and angiotensin converting enzyme (ACE) inhibitors, vitamins, or LDL apheresis are urgently required. Such trials will clarify the effect of treating dyslipidemia on the progression of renal insufficiency and dialysis-related cardiovascular complications.

Lysophosphatidylcholine induces platelet-derived growth factor gene expression in a human mesangial cell line

BACKGROUND

Oxidized low-density lipoprotein (oxLDL) has been considered important in the pathogenesis of progressive renal injury. Lysophosphatidylcholine (lysoPC) is a major phospholipid component of oxLDL. On the other hand, platelet-derived growth factor (PDGF) has also been implicated in proliferative disease of the kidney. This study investigated the difference in the potential of PC and lysoPC to induce DNA synthesis and PDGF gene expression in a human glomerular mesangial cell line (HMCL).

METHODS

DNA synthesis in HMCL was measured by [3H] thymidine incorporation. The mRNA expression levels of the PDGF A chain and B chain genes were measured using reverse transcription-polymerase chain reaction.

RESULTS

LysoPC treatment up-regulated the [3H] thymidine incorporation level in a dose-dependent fashion. The [3H] thymidine incorporation level in HMCL coincubated with lysoPC started to increase after 4 hours of treatment, peaked at 24 hours, and decreased thereafter. The level in HMCL incubated with 100 microM of lysoPC (palmitoyl or stearoyl) increased to 7- or 10-fold of the control at peak time, respectively. However, PC treatment did not increase [3H] thymidine incorporation in HMCL. PC treatment did not induce mRNA expression of either PDGF A or B chain genes. LysoPC did not induce PDGF A chain mRNA expression either. The only B chain mRNA expression was induced by lysoPC. The mRNA expression level in HMCL treated with 50 microM lysoPC for two hours increased to 1.6-fold that of the control.

CONCLUSION

LysoPC may induce DNA synthesis in a mesangial cell through the induction of PDGF BB as an autocrine and paracrine growth factor.

Expression of murine IL-12 is regulated by translational control of the p35 subunit

IL-12 is a heterodimer of two subunits, p35 and p40, encoded by separate genes that are regulated independently. To investigate the mechanisms underlying the regulation of the p35 gene, we characterized murine p35 expression in the B cell lymphoma line A20 and in bone marrow-derived dendritic cells. Multiple transcription start sites were identified in both cell types, resulting in four p35 mRNA isoforms (types I-IV) that differ in the number and position of upstream ATGs in their 5' untranslated regions. In nonstimulated cells, the predominant forms of p35 message (types II and IV) contained an additional upstream ATG, whose presence was shown to inhibit the downstream translation of the p35 subunit. After LPS stimulation, however, transcription initiated from alternate positions, so that the proportion of transcripts not containing this upstream ATG (types I and III) was significantly increased in the population of p35 mRNA. These type I and type III transcripts readily supported translation of the p35 subunit and its incorporation into bioactive IL-12. Furthermore, p35 mRNA levels were substantially up-regulated after LPS stimulation in both cell types. Thus, our results show that p35 gene expression is highly regulated by both transcriptional and translational mechanisms.

High level transcription of the complement regulatory protein CD59 requires an enhancer located in intron 1

CD59 is a complement regulatory protein and may also act as a signal-transducing molecule. CD59 transgenic mice have been generated using a CD59 minigene (CD59 minigene-1). Although this minigene contained a 4.6-kilobase pair 5'-flanking region from the human CD59 gene as a promoter, the expression levels of the CD59 mRNA were substantially lower than those observed in humans, suggesting that CD59 gene expression might also require other transcriptional regulatory elements such as an enhancer. To investigate the transcriptional regulation of the CD59 gene, we used three cell lines that express CD59 at different levels. We have identified DNase I-hypersensitive sites in intron 1 in HeLa cells, which express CD59 at high levels, but not in Jurkat (intermediate level) or Raji cells (low level). Furthermore, cell line-specific enhancer activity was detected in a fragment containing these DNase I-hypersensitive sites. The CD59 enhancer was mapped to between -1155 and -888 upstream of the 5'-end of exon 2. To investigate the enhancer activity in vivo, a new CD59 minigene was constructed by the addition of the enhancer fragment into CD59 minigene-1. High expressor CD59 transgenic mice were generated using the new minigene.

Molecular cloning and expression of glucuronyltransferase I involved in the biosynthesis of the glycosaminoglycan-protein linkage region of proteoglycans

We isolated a cDNA encoding a novel glucuronyltransferase from human placenta cDNA with the use of the degenerate reverse transcriptase-polymerase chain reaction method. Degenerate primers were designed based upon the amino acid sequence alignment of rat glucuronyltransferase (GlcAT-P) involved in the biosynthesis of the carbohydrate epitope HNK-1 with putative proteins in Caenorhabditis elegans and Schistosoma mansoni. The new cDNA sequence revealed an open reading frame coding for a protein of 335 amino acids with a type II transmembrane protein topology. The amino acid sequence displayed 43% identity to the rat GlcAT-P, and the highest sequence identity was found in the COOH-terminal catalytic domain. The expression of a soluble recombinant form of the protein in COS-1 cells produced an active glucuronyltransferase with marked specificity for a glycoserine Galbeta1-3Galbeta1-4Xylbeta1-O-Ser. In contrast, asialoorosomucoid, which contains the Galbeta1-4GlcNAc sequence and is a good acceptor substrate for the GlcAT-P, did not serve as an acceptor. The reaction product was sensitive to beta-glucuronidase digestion and co-chromatographed with authentic GlcAbeta1-3Galbeta1-3Galbeta1-4Xylbeta1-O-Ser in high-performance liquid chromatography, suggesting that the enzyme is a beta1, 3-glucuronyltransferase. These results indicate that this new member of the glucuronyltransferase gene family is the enzyme previously described as glucuronyltransferase I that forms the glycosaminoglycan-protein linkage region, GlcAbeta1-3Galbeta1-3Galbeta1-4Xylbeta1-O-Ser, of proteoglycans.

Regulation of IL-18 (IFN-gamma-inducing factor) gene expression

IL-18 (also known as IFN-gamma-inducing factor), although structurally unrelated to IL-12, shares with it the role of activating NK cells and polarizing T cells toward Th1 cell function. To understand how the IL-18 gene (and consequently Th1 function) is regulated, we have determined the gene structure and investigated the mechanisms of transcriptional control and cell type expression. The mouse IL-18 gene comprises seven exons distributed over 26 kb. Exons 1 and 2 of this gene are 5'-noncoding exons. Promoter activity was detected upstream of these noncoding exons in two distinct regions. Both promoters are TATA-less and not G+C rich. The promoter activity located upstream of exon 2 was shown to act constitutively, while the activity located upstream of exon 1 was up-regulated in activated macrophage and T cell lines. IL-18 gene expression may be regulated in a wide range of cell types by the activities of these two distinct promoters. IL-18 is known to be synthesized as a precursor, pro-IL-18, and its maturation is controlled by IL-1beta-converting enzyme (ICE). We observed concordant expression of IL-18 and ICE mRNAs in a wide range of cell types, unlike the more restricted expression of IL-12 p40 mRNA. The widespread IL-18 mRNA distribution and the special relationship with ICE lead us to the hypothesis that IL-18 expression may be coupled with apoptotic processes involving activation of ICE or ICE-like proteinase.

Regulation of IL-18 (IFN-gamma-inducing factor) gene expression

IL-18 (also known as IFN-gamma-inducing factor), although structurally unrelated to IL-12, shares with it the role of activating NK cells and polarizing T cells toward Th1 cell function. To understand how the IL-18 gene (and consequently Th1 function) is regulated, we have determined the gene structure and investigated the mechanisms of transcriptional control and cell type expression. The mouse IL-18 gene comprises seven exons distributed over 26 kb. Exons 1 and 2 of this gene are 5'-noncoding exons. Promoter activity was detected upstream of these noncoding exons in two distinct regions. Both promoters are TATA-less and not G+C rich. The promoter activity located upstream of exon 2 was shown to act constitutively, while the activity located upstream of exon 1 was up-regulated in activated macrophage and T cell lines. IL-18 gene expression may be regulated in a wide range of cell types by the activities of these two distinct promoters. IL-18 is known to be synthesized as a precursor, pro-IL-18, and its maturation is controlled by IL-1beta-converting enzyme (ICE). We observed concordant expression of IL-18 and ICE mRNAs in a wide range of cell types, unlike the more restricted expression of IL-12 p40 mRNA. The widespread IL-18 mRNA distribution and the special relationship with ICE lead us to the hypothesis that IL-18 expression may be coupled with apoptotic processes involving activation of ICE or ICE-like proteinase.

Developmental regulation of the sulfation profile of chondroitin sulfate chains in the chicken embryo brain

Developmentally regulated and cell type-specific expression of distinct sulfated glycosaminoglycan structures on cell surface proteoglycans is increasingly recognized as providing information relevant to cell-cell interactions and differentiation in developing organisms. In this report, developmental regulation of both the sulfation profile of chondroitin sulfate chains and activities of chondroitin 4-sulfotransferase (C4ST) and chondroitin 6-sulfotransferase (C6ST) were evaluated in embryonic chicken brain. The results revealed that the sulfation profile and the sulfotransferase activities changed markedly with development, and these alterations were precisely coordinated. Specifically, the proportions of both chondroitin 6-sulfate to 4-sulfate and C6ST to C4ST activities progressively decreased with development. In addition, the total amounts of both chondroitin sulfate chains and the sulfotransferase activities were highest during early embryonic stages and decreased sharply as the development reached completion. The developmental expression of the C6ST gene was also found to parallel the developmental down-regulation of both the C6ST activity and the chondroitin 6-sulfate structure. These findings suggest that the developmentally regulated expression of the sulfotransferases is a predominant factor for stage-specific regulation of chondroitin sulfate structures.

Inverse gene expression of prostacyclin and thromboxane synthases in resident and activated peritoneal macrophages

Prostacyclin and thromboxane A2 produced from prostaglandin H2 are known to be important modulators with opposite biological activities. To examine possible roles of these prostanoids in immune responses, we have studied the gene expression of prostacyclin synthase (PGIS) and thromboxane synthase (TXS) in murine resident macrophages or in macrophages elicited with casein or bacillus Calmette-Guérin (BCG). Northern blot analyses showed that the PGIS mRNA was expressed in a decreasing order in the resident, and casein- and BCG-elicited macrophages. In contrast, the TXS mRNA was expressed in an increasing order in the resident, and casein- and BCG-elicited macrophages. On the other hand, the mRNA for cyclooxygenase-2, which produces PGH2 and participates in the production of prostanoids in inflammation, was expressed in both the resident and BCG-elicited macrophages but barely in the casein-elicited cells. In situ hybridization analysis showed that the expression of mRNAs for PGIS and TXS was ascribable not only to the alteration of the expression levels of both mRNAs in the each macrophage but also to the changes in subpopulations of the cells expressing these mRNAs. These observations suggested that the inverse gene expression of PGIS and TXS in macrophages contributes to immune responses by modulating the relative levels of prostacyclin and thromboxane A2.

Thyroid hormone-mediated enhancement of heterodimer formation between thyroid hormone receptor beta and retinoid X receptor

A subset of nuclear receptors, including those for thyroid hormone (TR), retinoic acid, vitamin D3, and eicosanoids, can form heterodimers with the retinoid X receptor (RXR) on DNA regulatory elements in the absence of their cognate ligands. In a mammalian two-hybrid assay, we have found that recruitment of a VP16-RXR chimera by a Gal4-TRbeta ligand-binding domain fusion is enhanced up to 50-fold by thyroid hormone (T3). This was also observed with a mutant fusion, Gal4-TR(L454A), lacking ligand-inducible activation function (AF-2) and unable to interact with putative coactivators, suggesting that the AF-2 activity of TR or intermediary cofactors is not involved in this effect. The wild-type and mutant Gal4-TR fusions also exhibited hormone-dependent recruitment of RXR in yeast. Hormone-dependent recruitment of RXR was also evident with another Gal4-TR mutant, AHTm, which does not interact with the nuclear receptor corepressor N-CoR, suggesting that ligand-enhanced dimerization is not a result of T3-induced corepressor release. Finally, we have shown that the interaction between RXR and TR is augmented by T3 in vitro, arguing against altered expression of either partner in vivo mediating this effect. We propose that ligand-dependent heterodimerization of TR and RXR in solution may provide a further level of control in nuclear receptor signaling.

The regional distribution and cellular localization of mRNA encoding rat prostacyclin synthase

The cloned cDNA for rat prostacyclin synthase was found to contain a 1503-bp open reading frame which encoded a 501-amino acid protein sharing 84.0% identity with the human enzyme. RNA blot analysis revealed that the rat prostacyclin synthase mRNA, as a single species of 2.1 kb, is expressed abundantly in the aorta and uterus. High levels of expression were also observed in the stomach, lung, heart, testis, liver, and skeletal muscle. Low but significant expression was also seen in the brain and kidney. Furthermore, the regional distribution and cellular localization of prostacyclin synthase mRNA were examined by in situ hybridization analysis of rat tissue sections. The definitive signals for the mRNA were localized in smooth muscle cells of the arteries, bronchi and uterus, and in the cells of the fibrous tunic surrounding the seminiferous tubules, which are characterized as smooth muscle cells. Besides smooth muscle cells, signals were also detected in the fibroblasts of the heart myocardium, lung parenchyma cells and kidney inner medulla tubules and interstitial cells.

Human gene encoding prostacyclin synthase (PTGIS): genomic organization, chromosomal localization, and promoter activity

The prostacyclin synthase gene isolated from human genomic libraries (PTGIS) consists of 10 exons spanning approximately 60 kb. All the splice donor and acceptor sites conform to the GT/AG rule. Genomic Southern blot and fluorescence in situ hybridization analyses revealed that the human prostacyclin synthase gene is present as a single copy per haploid genome and is localized on chromosome 20q13. 11-q13.13. The 1.5-kb sequence of the 5'-upstream of the translational initiation site contained both GC-rich and pyrimidine-rich regions and consensus sequences of the transcription factor recognition sites such as Sp1, AP-2, the interferon-gamma response element, GATA, NF-kappaB, the CACCC box, and the glucocorticoid response element. The core binding sequence (GAGACC) of the shear stress responsive element was also found in the 5'-flanking region of the gene. The major product of the primer extension analysis suggested that the transcription of the gene started from the positions around 49 bp upstream of the translational initiation codon. Transient transfection experiments using human aortic and bovine arterial endothelial cells demonstrated that the GC-rich region (positions -145 to -10) possessed a significant promoter activity. The 6-kb downstream sequence of the translational termination codon contained multiple polyadenylation signals, Alu repeat sequences, and the consensus sequence of the primate-repetitive DNA element, MER1. Two sizes of the prostacyclin synthase mRNAs (approximately 6 and 3.3 kb) were detected with the human aorta and lung. RNA blot hybridization analysis using the 3'-untranslated region as probe indicated that the sizes of the 3'-flanking regions were different in the major 6-kb and minor 3.3-kb mRNAs.

Structure and chromosomal location of the mouse interleukin-12 p35 and p40 subunit genes

Interleukin-12 (IL-12) is a heterodimeric cytokine composed of p35 and p40 subunits and is required for induction of T helper 1 (Th1) responses. Knowledge of how the IL-12 gene is regulated will permit an understanding of susceptibility and resistance to pathogenic microbes and to autoiummune diseases. In this report, we provide the gene structures, nucleotide sequences and chromosomal assignment for the p35 and p40 subunits of mouse IL-12. The p35 and p40 subunit genes are distributed over 8 kb and 14 kb, and map to chromosomes 3 and 11, respectively. The p35 subunit gene consists of eight exons, including a 5'-noncoding exon that was defined by sequence comparison of genomic DNA with the 5'ends of novel cDNA molecules. Transcription of p35 mRNA can start from the first exon but can also initiate further downstream. Potential transcription regulatory elements, AP1, AP2, AP3, NF-kB and GATA recognition sequences, are located within 523 bp upstream of the p35 gene; however, no TATA box was identified. The p40 subunit gene consists of eight exons. A TATA box is located 30 bp upstream from the transcription start site, and AP1, AP3, GATA, and Pu.1 recognition sequences are located within 690 bp upstream of the p40 gene. An AGTTTCTACTTT sequence, which acts as an interferon-gamma response element in the promoter of the major histocompatibility complex class I gene, was also found upstream of the p40 gene.

Overexpression of prostacyclin synthase inhibits growth of vascular smooth muscle cells

To define the local effects of prostacyclin (PGI2) on the growth of vascular smooth muscle cells (VSMC), we transfected VSMC with an expression vector harboring the cDNA for PGI2 synthase (PGIS), which catalyzes the rearrangement of prostaglandin H2 to PGI2. Transfection of the human PGIS cDNA into rat VSMC did not affect DNA synthesis under serum-free basal conditions, but it increased PGI2 synthesis and decreased DNA synthesis under serum-stimulated conditions (in the presence of 1 or 5% fetal calf serum). These results demonstrated that locally synthesized PGI2 can exert autocrine and/or paracrine inhibitory effects on VSMC growth. It was also suggested that in vivo transfer of PGIS gene may be useful for the gene therapy for vascular disease such as neointimal hyperplasia.

Transcriptional regulation of human prostaglandin-endoperoxide synthase-2 gene by lipopolysaccharide and phorbol ester in vascular endothelial cells. Involvement of both nuclear factor for interleukin-6 expression site and cAMP response element

There exist two distinct isozymes of prostaglandin-endoperoxide synthase (PES). PES-2 mRNA is synergistically induced by lipopolysaccharide (LPS) and 12-O-tetradecanoylphorbol-13-acetate (TPA) in bovine arterial endothelial cells. On the other hand, PES-1 mRNA is constitutively expressed under these conditions. Therefore, the promoter activities of the human genes for PES-1 and -2 in bovine arterial endothelial cells were examined. The 5'-flanking region of the human PES-2 gene (nucleotides -327 to +59) showed promoter activity inducible by LPS and TPA using transient transfection analysis, whereas that of the PES-1 gene (nucleotides -1010 to +69) showed constitutive promoter activity. Destruction of both consensus sequences for the nuclear factor responsible for the interleukin-6 expression (NF-IL6) site (nucleotides -132 to -124) and the cyclic AMP response element (CRE) (nucleotides -59 to -53) of the human PES-2 gene markedly reduced the promoter activity (25%) of the PES-2 gene after combined treatment with LPS and TPA, although single destruction of the NF-IL6 site or the CRE slightly reduced the promoter activity (60 or 90%, respectively). Moreover, cotransfection experiments showed that a trans-acting factor, CCAAT enhancer binding protein delta (C/EBP delta), which binds to both the NF-IL6 site and the CRE, increased the promoter activity of the PES-2 gene mainly through the CRE. C/EBP delta mRNA was rapidly induced by LPS. Collectively, these results suggest that transcription of the PES-2 gene in vascular endothelial cells is regulated through combination of the NF-IL6 site and the CRE and that C/EBP delta functions as one of the trans-acting factors.

Functional analysis of a transactivation domain in the thyroid hormone beta receptor

Hormone-dependent transcriptional activation (AF-2) by the thyroid hormone beta receptor (TR beta) localizes to its carboxyl-terminal domain. A putative transactivation sequence within this domain was analyzed by mutating individual residues to alanine. Mutant receptor carboxyl-terminal domains were tested coupled to the heterologous DNA binding domain of Gal4. A single mutant receptor (E460A) showed normal hormone binding and activation, whereas several others (P453A, F455A, L456A, F459A) exhibited impaired transactivation which correlated with their reduced ligand binding. Two mutations (L454A, E457A) were able to dissociate these properties, generating transcriptionally defective mutant proteins with preserved hormone binding. A further conservative substitution (E457D) was also nonfunctional, and these three mutations were equally deleterious when tested in the context of full-length TR beta with a natural thyroid hormone response element containing promoter. This loss of activity was not due to altered DNA binding or expression of mutant receptors in cultured cells. They also retained the ability to recruit VP16-tagged retinoid X receptor in vivo as well as bind the basal transcription factors TFIIB and TBP in vitro. Our observations indicate that conserved hydrophobic (Leu454) and charged (Glu457) residues mediate AF-2 activity of TR beta, possibly via a co-activator that has yet to be identified.

Spectrum of transcriptional, dimerization, and dominant negative properties of twenty different mutant thyroid hormone beta-receptors in thyroid hormone resistance syndrome

Resistance to thyroid hormone (RTH) is usually dominantly inherited and characterized by elevated thyroid hormone levels, impaired feedback inhibition of pituitary TSH production, and variable hormonal responsiveness in peripheral tissues. We have identified 20 different mutations in the thyroid hormone beta-receptor (TR beta) gene in RTH and assayed mutant receptor properties using the TSH alpha subunit gene promoter or promoters containing three different types of positive thyroid response element (TRE). Dominant negative inhibition of wild type TR beta action by mutant receptors was also tested. The mutant receptors exhibited differing transcriptional inhibitory properties and dominant negative potential with the TSH alpha promoter that correlated with their impaired hormone binding, whereas transactivation and dominant negative effects with promoters containing positive TREs varied depending on their configuration. Heterodimeric mutant receptor-retinoid X receptor (RXR) interactions, either in cultured cells or as TRE-bound complexes in gel retardation assays, were uniformly preserved, whereas homodimeric receptor interactions could not be detected in vivo, and in vitro homodimer formation on TREs was variably reduced or absent for some mutant proteins. We correlate these findings with the distribution of receptor mutations that cluster in two areas within the hormone binding domain outside putative dimerization regions and show that artificial mutations that impaired heterodimerization abrogated dominant negative activity. Therefore, we suggest that the dominant negative effect of mutant receptors in the pituitary-thyroid axis generates the characteristic biochemical abnormality of RTH and that variable resistance in other tissues may be due to response element-dependent differences in their dominant negative potential.

Genetic analysis of 29 kindreds with generalized and pituitary resistance to thyroid hormone. Identification of thirteen novel mutations in the thyroid hormone receptor beta gene

Resistance to thyroid hormone (RTH), with elevated serum free thyroid hormones and nonsuppressed thyrotropin levels, is either relatively asymptomatic, suggesting a generalized disorder (GRTH) or associated with thyrotoxic features, indicating possible selective pituitary resistance (PRTH). 20 GRTH and 9 PRTH cases, sporadic or dominantly inherited, were analyzed. Affected individuals were heterozygous for single nucleotide substitutions in the thyroid hormone receptor beta gene, except for a single case of a seven nucleotide insertion. With one exception, the corresponding 13 novel and 7 known codon changes localized to and extended the boundaries of two mutation clusters in the hormone-binding domain of the receptor. 15 kindreds shared 6 different mutations, and haplotype analyses of the mutant allele showed that they occurred independently. The majority (14 out of 19) of the recurrent but a minority (1 out of 10) of unique mutations were transitions of CpG dinucleotides. Mutant receptor binding to ligand was moderately or severely impaired and did not correlate with the magnitude of thyroid dysfunction. There was no association between clinical features and the nature or location of a receptor mutation. These observations suggest that GRTH and PRTH are phenotypic variants of the same genetic disorder, whose clinical expression may be modulated by other non-mutation-related factors.

Abundant expression of thromboxane synthase in rat macrophages

The cloned cDNA for rat thromboxane (TX) synthase with a size of 1851 bp contained a 1599-bp open reading frame which encoded a 533-amino acid protein sharing 79.7% identity with human TX synthase. RNA blot analysis was carried out with rat cells and tissues. Rat peritoneal macrophages most abundantly expressed mRNA for TX synthase, and its level was not changed by in vivo stimulation of casein. Bone marrow, spleen, lung and thymus also expressed the TX synthase gene. These findings suggest the possibility that TXA2 plays a role in the immune system.

A human monoclonal antibody to high-frequency red cell antigen Jra

A human-mouse heterohybridoma (HMR0921) secreting human monoclonal IgG3, lambda antibody was produced from peripheral blood lymphocytes of a healthy blood donor with serum antibody to Jra, by EBV transformation and hybridization with mouse myeloma cell line P3X63Ag8.653. The reactivity of HMR0921 antibody was assessed by antiglobulin test with a panel of red cells including 14 different rare blood types. Only Jr(a-) red cells were negative. The strict specificity of this antibody to Jra antigen was further confirmed by absorption test with fluorescence flow cytometry. On screening of 28,744 blood donor samples by HMR0921 antibody, we detected 19 agglutination-negative samples, which were confirmed as Jr(a-) by conventional anti-Jra antisera. Therefore, our HMR0921 antibody is extremely useful for detecting rare Jr(a-) blood.

Primary amenorrhoea and infertility due to a mutation in the beta-subunit of follicle-stimulating hormone

We report a woman with primary amenorrhoea and infertility associated with an isolated deficiency of pituitary follicle-stimulating hormone (FSH), but normal luteinizing hormone (LH) secretion. Ovulation was induced by administration of exogenous FSH and resulted in a successful pregnancy. Sequence analysis of the FSH beta-subunit gene indicated that she is homozygous for a two nucleotide frameshift deletion in the coding sequence. Her mother and son are heterozygous for this mutation. This deletion results in an alteration of amino acid codons 61-86 followed by a premature termination codon. The predicted truncated beta-subunit peptide lacks regions which are important for association with the alpha subunit and for binding to and activation of the FSH receptor. Abnormalities of FSH structure or function might be an under recognised but treatable cause of infertility.

Functional properties of a novel mutant thyroid hormone receptor in a family with generalized thyroid hormone resistance syndrome

OBJECTIVE

We wished to ascertain whether a mutation in the thyroid hormone receptor beta gene was present in a family with generalized thyroid hormone resistance syndrome and to characterize the functional properties of this mutant receptor.

DESIGN

Blood samples were obtained from family members for hormone assays and genomic DNA was isolated from leucocytes for genetic analyses.

PATIENTS

Three members (B,C,E) of a family with possible thyroid hormone resistance and two normal family members (A,D) were studied.

MEASUREMENTS

Basal thyroid function tests together with serum sex hormone binding globulin (SHBG) levels were measured. The thyroid hormone receptor beta gene was amplified using the polymerase chain reaction and the receptor mutation identified by sequence analysis. The ability of mutant receptor to bind T3, interact with a specific DNA sequence and to modulate target gene expression was tested. The effects of mutant receptor on co-expressed wild type receptor action were determined.

RESULTS

Patients with resistance had raised levels of T4 and T3 together with inappropriately normal serum TSH and SHBG whereas unaffected individuals had a normal hormone profile. A single nucleotide substitution corresponding to a glycine to serine mutation at codon 340 (G340S) in the hormone binding domain was identified in one of the two beta receptor gene alleles in patients with resistance, but not in the normal family members. When expressed in vitro, this receptor protein (G340S), as well as a related (G340R) mutant identified in another family, retained the ability to bind to a specific DNA sequence but were unable to bind ligand or to activate or repress target gene expression. In addition both receptor mutants were capable of inhibiting the function of wild type thyroid hormone receptor in a co-expression assay but differed in their inhibitory potential.

CONCLUSIONS

We report a second type of mutation (Gly to Ser) in codon 340 of hTR beta in a family with generalized thyroid hormone resistance. Mutations at this site eliminate T3 binding, causing a loss of hormone-stimulated receptor function. However, the mutant receptors retain the ability to block normal receptor action. The occurrence of different mutations at the same site suggests that alterations in this region of the receptor may be important for generating the clinical phenotype of this disorder.

Prevention of aortic calcification in patients on hemodialysis by long-term administration of vitamin E

The effects of vitamin E on the progress of atherosclerosis in patients on hemodialysis was investigated clinically using ACI. There was a significant suppression of the increase in ACI in group A, compared to group B, at the time of observation in each year. On the other hand, no significant changes were noted in BWD, CTR, BP and blood chemical examination, except that the level of MDA was significantly decreased in group A as compared with that in group B 4 years later. Since ACI is an index representing atherosclerosis, the results of this study seemed to suggest that the progress of atherosclerosis was suppressed by long-term administration of vitamin E in patients on hemodialysis.

Dose-dependent pharmacokinetics and first-pass metabolism of acetaminophen in rats

In order to investigate the in vivo first-pass metabolism of acetaminophen (AAP) following the oral and intraduodenal administration in rats, a pharmacokinetic compartment model including absorption process was developed. Using the parameters for the disposition kinetics of AAP and its metabolites, sulfate and glucuronide, which were determined in the separate study, the extent of the first-pass metabolism and the contribution of sulfation and glucuronidation to the total first-pass metabolism in vivo were quantitatively estimated. As for the results, the first-pass metabolism of AAP following the oral and intraduodenal administration was mainly attributable to the sulfo-conjugation pathway in rats. The sulfation of AAP in the intestine and/or in the liver during the first-pass was proved to be a saturable process. Then, the sulfation in the first-pass metabolism showed the dose- and absorption rate-dependent kinetics. Thus, the pharmacokinetic model including the absorption process proposed in the present study was proved to be valid and useful for the estimation of in vivo first-pass metabolism of AAP in rats.

[Clinical efficacy of sulbactam/ampicillin in the field of pediatrics]

Sulbactam (SBT) is a new derivative of the basic penicillin nucleus. It effectively and irreversibly inhibits several important bacterial beta-lactamases and displays synergistic effects against the resistant organisms when co-administered with ampicillin (ABPC). SBT/ABPC, which is a fixed combination of SBT and ABPC in a 1:2 ratio, was studied for clinical efficacy in the field of pediatrics. Patients treated were infants and children ranging from 12 days to 13 years and 2 months old suffering from acute tonsillitis in 2 cases, acute bronchitis in 2 cases, septicemia in 2 cases, acute enteritis, acute pyelonephritis and osteomyelitis in 1 case each, a total of 9 cases. SBT/ABPC was administered 100-300 mg/kg in daily doses and durations of treatment ranged from 4 to 17 days. Clinical results were "excellent" in 6 and "good" in 2: the efficacy rate was 88.9% or 8 cases out of 9. Neither clinical side effects nor abnormal laboratory findings obviously attributable to SBT/ABPC were observed in any cases.

Selective killing of carcinoembryonic-antigen (CEA)-producing cells in vitro by the immunoconjugate cytorhodin-S and CEA-reactive cytorhodin-S antibody CA208

Cytorhodin-S, an anthracycline derivative, was covalently coupled to a monoclonal antibody (mAb) CA208, against carcinoembryonic antigen (CEA) in order to achieve selective killing of a CEA-producing colon carcinoma cell line, COLO 205. The conjugate (15 molecules of drugs/antibody) retained substantial antibody activity as well as drug activity as assessed by enzyme-linked immunosorbent assay and 24-h L1210 proliferation assay, respectively. Furthermore, the conjugate inhibited the growth of COLO 205 cells in a short-term cytostatic assay. This cytostatic effect of the immunoconjugate on COLO 205 cells was inhibited in a dose-dependent manner by pretreatment of the cells with unconjugated CA208 mAb. In addition, chloroquine, a lysosomotropic agent, inhibited the cytostatic effect of the immunoconjugate, indicating the involvement of lysosomal enzymes in releasing drugs from the immunoconjugate. The antibody (CA208) was significantly incorporated into the cytoplasm of COLO 205 cells as demonstrated by immuno-electron microscopy. These in vitro results indicate that cytorhodin-S may be a good partner in immunoconjugates. However, in vivo animal experiments with the immunoconjugate revealed that the immunoconjugate was not so effective in prolonging survival. Thus, in vivo efficacy of this immunoconjugate remains to be further improved in application to cancer immunotherapy.

[Pharmacokinetics and clinical effects of sultamicillin fine granules in pediatrics]

We have evaluated sultamicillin (SBTPC) fine granules for pharmacokinetics and therapeutic effectiveness in children. The results are summarized as follows. 1. Pharmacokinetic parameters after the oral administration of single dose of 5.0 mg per kg body weight in 1 child were as follows: The peak serum concentrations of ampicillin (ABPC) and sulbactam (SBT) were 1.92 micrograms/ml at 1 hour and 1.85 micrograms/ml at 1 hour, respectively. The half-lives in serum and urinary excretion rate for ABPC and SBT were similar. 2. A clinical study was performed on 15 children with infections, including 4 with tonsillitis, 5 with pharyngitis, 2 each with bronchitis, cystitis, and urinary tract infections. Doses ranging from 6.7 to 18.2 mg/kg body weight were given tid. or qid. Lengths of treatment ranged from 5 to 10 days. The therapeutic responses were considered "excellent" in 6 and "good" in 9, with an effectiveness rate of 100%. 3. As to side effects of the drug, diarrhea was observed in 1 patient. It was concluded that SBTPC was a promising drug for the treatment of bacterial infections in children.