Fibroblast growth enhancing activity of tumor necrosis factor and its relationship to other polypeptide growth factors

Tumor necrosis factor (TNF) is a monocyte-derived protein cytotoxic or cytostatic for some tumor cell lines. Here we show that highly purified E. coli-derived recombinant human TNF stimulated the growth of human FS-4 diploid fibroblasts. Stimulation of cell growth was demonstrable at a TNF concentration of 10 pg/ml (3 X 10(-13) M). Maximal stimulation was attained at TNF concentrations of 10 ng/ml (3 X 10(-10) M) or higher. Growth-stimulatory activity of TNF was inhibited by an mAb neutralizing the cytotoxic activity of TNF. Growth stimulation was not inhibited by another mAb specific for TNF, lacking neutralizing activity for the cytotoxic activity of TNF. Growth stimulation by TNF was more marked and more sustained in the presence of greater than or equal to 10% FCS than in medium with less than or equal to 5% FCS. Addition of TNF to confluent FS-4 cultures also produced a marked stimulation of cell growth in the presence of fresh FCS, while a much less marked stimulation was seen in the absence of FCS. Stimulation of confluent cultures by TNF in serum-free medium was enhanced by insulin, suggesting that insulin or insulin-like growth factor(s) in the serum can act synergistically with TNF in producing growth stimulation. While the growth-stimulatory effects of TNF and insulin were synergistic, the actions of TNF and epidermal growth factor (EGF) were less than additive, suggesting that TNF and EGF may activate identical or similar pathways. We conclude that stimulation of cell growth is probably a physiological function of TNF, and that the cytotoxic and cytostatic actions of TNF may be the result of an anomalous growth signal transduction in neoplastic cells lacking the constraints of normal growth control mechanisms.

A novel superoxide-producing NAD(P)H oxidase in kidney

During phagocytosis, gp91(phox), the catalytic subunit of the phagocyte NADPH oxidase, becomes activated to produce superoxide, a precursor of microbicidal oxidants. Currently increasing evidence suggests that nonphagocytic cells contain similar superoxide-producing oxidases, which are proposed to play crucial roles in various events such as cell proliferation and oxygen sensing for erythropoiesis. Here we describe the cloning of human cDNA that encodes a novel NAD(P)H oxidase, designated NOX4. The NOX4 protein of 578 amino acids exhibits 39% identity to gp91(phox) with special conservation in membrane-spanning regions and binding sites for heme, FAD, and NAD(P)H, indicative of its function as a superoxide-producing NAD(P)H oxidase. The membrane fraction of kidney-derived human embryonic kidney (HEK) 293 cells, expressing NOX4, exhibits NADH- and NADPH-dependent superoxide-producing activities, both of which are inhibited by diphenylene iodonium, an agent known to block oxygen sensing, and decreased in cells expressing antisense NOX4 mRNA. The human NOX4 gene, comprising 18 exons, is located on chromosome 11q14.2-q21, and its expression is almost exclusively restricted to adult and fetal kidneys. In human renal cortex, high amounts of the NOX4 protein are present in distal tubular cells, which reside near erythropoietin-producing cells. In addition, overexpression of NOX4 in cultured cells leads to increased superoxide production and decreased rate of growth. The present findings thus suggest that the novel NAD(P)H oxidase NOX4 may serve as an oxygen sensor and/or a regulator of cell growth in kidney.

MDR1 genotype-related pharmacokinetics of digoxin after single oral administration in healthy Japanese subjects

PURPOSE

To evaluate the MDR1 genotype frequency in the Japanese population and to study the relationship between the MDR1 genotype and the pharmacokinetics of digoxin after single oral administration in healthy subjects.

METHODS

The MDR1 genotype at exon 26 was determined in 114 healthy volunteers by polymerase chain reaction-restriction fragment length polymorphism. The serum concentration-time profile of digoxin was examined after single oral administration at a dose of 0.25 mg.

RESULTS

It was found that 35.1 % (40/114) of subjects were homozygous for the wild-type allele (C/C). 52.6% (60/114) were compound heterozygotes with a mutant T-allele (C3435T) (C/T), and 12.3% (14/114) were homozygous for the mutant allele (T/T). There was no effect of gender or age on the distribution. The serum concentration of digoxin after a single oral administration increased rapidly, attaining a steady state in all subjects; however, it was lower in the subjects harboring the T-allele. AUC0-4 h values (+/-SD) were 4.11 +/- 0.57, 3.20 +/- 0.49. and 3.27 +/- 0.58 ng h/ml, respectively, with a significant difference between C/C and C/T or T/T.

CONCLUSIONS

The serum concentration of digoxin after single oral administration was lower in the subjects harboring a mutant allele (C3435T) at exon 26 of the MDR1 gene.

Analysis and typing of the vacA gene from cagA-positive strains of Helicobacter pylori isolated in Japan

Approximately 50% of Helicobacter pylori strains produce a cytotoxin that is encoded by vacA and that induces vacuolation of eukaryotic cells. Mosaicism in vacA alleles was reported, and there are three different families of vacA signal sequences (s1a, s1b, and s2) and two different families of middle-region alleles (m1 and m2). In addition, the vacA genotype of a strain is associated with its cytotoxin phenotype and its capacity to induce peptic ulceration. To clarify the strain diversity of H. pylori in Japan, 87 Japanese clinical isolates of H. pylori (40 from patients with chronic atrophic gastritis, 25 from patients with duodenal ulcer, 16 from patients with gastric ulcer, 3 from patients with both duodenal and gastric ulcers, and 3 from patients with intestinal type gastric cancer) were characterized by vacA typing by PCR and DNA sequencing. Eighty-four of the 87 isolates were s1a/m1, one was s1b/m1, and two could not be typed. Moreover, all isolates in this study were cagA positive. There were no distinct differences between the cytotoxin-producing strains and cytotoxin-nonproducing strains within the 0.73-kb middle region. Japanese strains were highly homologous, with more than 96% identity in this region, in which maximum divergence has been reported. In addition, there were no associations between the specific vacA types and the level of in vitro cytotoxin activity or the clinical consequences. These results indicate that the cagA-positive, s1a/m1-type strains are common in Japan, regardless of the vacA phenotype or clinical outcome.

Suppression of cellular immunity by surgical stress

BACKGROUND

Suppression of cellular immunity is one of the host responses to surgical stress. In cancer patients this immunosuppression may accelerate the growth and metastasis of residual cancer cells, so it is desirable to restrict immunosuppression by surgical stress to a minimum. However, the extent and duration of immunosuppression caused by operations on gastrointestinal cancer, as well as the mechanisms involved, have not been determined.

METHODS

To clarify these points, we investigated immunocyte function and measured the blood levels of hormones, cytokines, and acute phase reactants from before to after operation in 20 patients with stage I gastrointestinal cancer.

RESULTS

In patients exposed to surgical stress, peripheral blood lymphocyte numbers and function were suppressed until at least 2 weeks postoperatively. This immunosuppression was mainly due to a decrease of helper-inducer T cells, cytotoxic T cells, natural killer cells, and interleukin-2 receptor-positive cells, as well as an increase of suppressor T cells. In addition, hypersecretion of cortisol and overproduction of immunosuppressive acidic protein were observed.

CONCLUSIONS

Cellular immunosuppression by surgical stress was mainly due to an increase of lymphocyte subsets that depress cellular immunity coupled with a decrease of the subsets that promote it. Overproduction of cortisol and immunosuppressive acidic protein in response to surgical stress may play an important role in the development of immunosuppression.

Association between gain-of-function mutations in PIK3CA and resistance to HER2-targeted agents in HER2-amplified breast cancer cell lines

BACKGROUND

The mechanism of resistance to human epidermal growth factor receptor 2 (HER2)-targeted agents has not been fully understood. We investigated the influence of PIK3CA mutations on sensitivity to HER2-targeted agents in naturally derived breast cancer cells.

MATERIALS AND METHODS

We examined the effects of Calbiochem (CL)-387,785, HER2 tyrosine kinase inhibitor, and trastuzumab on cell growth and HER2 signaling in eight breast cancer cell lines showing HER2 amplification and trastuzumab-conditioned BT474 (BT474-TR).

RESULTS

Four cell lines with PIK3CA mutations (E545K and H1047R) were more resistant to trastuzumab than the remaining four without mutations (mean percentage of control with 10 microg/ml trastuzumab: 58% versus 92%; P = 0.010). While PIK3CA-mutant cells were more resistant to CL-387,785 than PIK3CA-wild-type cells (mean percentage of control with 1 microM CL-387,785: 21% versus 77%; P = 0.001), CL-387,785 retained activity against BT474-TR. Growth inhibition by trastuzumab and CL-387,785 was more closely correlated with changes in phosphorylation of S6K (correlation coefficient, 0.811) than those of HER2, Akt, or ERK1/2. Growth of most HER2-amplified cells was inhibited by LY294002, regardless of PIK3CA genotype.

CONCLUSIONS

PIK3CA mutations are associated with resistance to HER2-targeted agents. PI3K inhibitors are potentially effective in overcoming trastuzumab resistance caused by PIK3CA mutations. S6K phosphorylation is a possibly useful pharmacodynamic marker in HER2-targeted therapy.

Oxidative DNA damage in diabetes mellitus: its association with diabetic complications

AIMS/HYPOTHESIS

Augmented oxidative stress induced by hyperglycaemia possibly contributes to the pathogenesis of diabetic complications. Oxidative stress is known to increase the conversion of deoxyguanosine to 8-oxo, 2'-deoxyguanosine in DNA. To investigate the possible contribution of oxidative DNA damage to the pathogenesis of diabetic complications, we measured the content of 8-oxo, 2'-deoxyguanosine in the urine and the blood mononuclear cells of Type II (non-insulin-dependent) diabetic patients.

METHODS

We studied 53 Type II diabetic patients and 39 age-matched healthy control subjects. We assayed 8-oxo, 2'-deoxyguanosine by HPLC-electrochemical detection method.

RESULTS

The content of 8-oxo, 2'-deoxyguanosine in the urine and the mononuclear cells of the Type II diabetic patients was much higher than that of the control subjects. Urinary 8-oxo, 2'-deoxyguanosine excretion and the 8-oxo, 2'-deoxyguanosine content in the mononuclear cells from the diabetic patients with complications were higher than those from the diabetic patients without complications. Urinary excretion of 8-oxo, 2'-deoxyguanosine was significantly correlated with the 8-oxo, 2'-deoxyguanosine content in the mononuclear cells. The 8-oxo, 2'-deoxyguanosine content in the urine and mononuclear cells was correlated with the haemoglobin A1c value.

CONCLUSIONS/INTERPRETATION

This is the first report of a direct association between oxidative DNA damage and the complications of diabetes. The augmented oxidative DNA damage in diabetes is speculated to contribute to the pathogenesis of diabetic complications.

Identification and characterization of a novel family of serine/threonine kinases containing two N-terminal LIM motifs

We previously isolated human cDNA coding for LIMK1 (LIM motif-containing protein kinase-1), a putative protein kinase containing two LIM motifs at the N terminus and an unusual protein kinase domain at the C terminus. In the present study, we isolated human cDNA encoding LIMK2, a second member of a LIMK family, with a domain structure similar to LIMK1 and 50% overall amino acid identity with LIMK1. The protein kinase domains of LIMK1 and LIMK2 are unique in that they contain an unusual sequence motif Asp-Leu-Asn-Ser-His-Asn in subdomain VIB and a highly basic insert between subdomains VII and VIII. Expression patterns of LIMK1 and LIMK2 mRNAs in human tissues differ significantly. Chromosomal localization of human LIMK1 and LIMK2 genes was assigned to 7q11.23 and 22q12, respectively, by fluorescence in situ hybridization. The Myc epitope-tagged LIMK1 and LIMK2 proteins transiently expressed in COS cells exhibited serine/threonine-specific kinase activity toward myelin basic protein and histone in in vitro kinase assay. Immunofluorescence and subcellular fractionation analysis revealed that Myc-tagged LIMK1 and LIMK2 were localized mainly in the cytoplasm. The "native" LIMK1 protein endogenously expressed in A431 epidermoid carcinoma cells also exhibited serine/threonine kinase activity. The specific activity of native LIMK1 from A431 cells was apparently much higher than that of "recombinant" LIMK1 ectopically expressed in COS cells, hence, it is likely that there is a mechanism, by which native LIMK1 is activated. A 140-kDa tyrosine-phosphorylated protein (pp140) was co-immunoprecipitated with native LIMK1 form A431 cell lysates; therefore, pp140 may be a LIMK1-associated protein involved in the regulation of LIMK1 function.

Neointima formation in a restenosis model is suppressed in midkine-deficient mice

Neointima formation is a common feature of atherosclerosis and restenosis after balloon angioplasty. To find a new target to suppress neointima formation, we investigated the possible role of midkine (MK), a heparin-binding growth factor with neurotrophic and chemotactic activities, in neointima formation. MK expression increased during neointima formation caused by intraluminal balloon injury of the rat carotid artery. Neointima formation in a restenosis model was strongly suppressed in MK-deficient mice. Continuous administration of MK protein to MK-deficient mice restored neointima formation. Leukocyte recruitment to the vascular walls after injury was markedly decreased in MK-deficient mice. Soluble MK as well as that bound to the substratum induced migration of macrophages in vitro. These results indicate that MK plays a critical role in neointima formation at least in part owing to its ability to mediate leukocyte recruitment.

A gene outside the human MHC related to classical HLA class I genes

By presenting antigenic peptides to T lymphocytes, major histocompatibility complex (MHC) class I molecules play important roles in the human immune system. Knowledge is limited on the evolutionary history of human MHC class I-related molecules. An expressed class I gene, MR1, has now been identified on human chromosome 1q25, outside the MHC. In contrast to other known human divergent class I genes, MR1 encodes peptide-binding domains similar to those encoded by human leukocyte antigen (HLA) class I genes on chromosome 6 and by nonmammalian classical MHC class I genes. This gene may thus contribute to understanding the evolution of the MHC.

Tob2, a novel anti-proliferative Tob/BTG1 family member, associates with a component of the CCR4 transcriptional regulatory complex capable of binding cyclin-dependent kinases

Human cDNAs encoding a novel member of Tob/BTG1 anti-proliferative family proteins were cloned. The putative protein product termed Tob2 consisted of 344 amino acids with high similarity to the Tob protein. The tob2 mRNA was 4.1 kb long and was ubiquitously expressed in human adult tissues, as was revealed by Northern blot hybridization. However, further in situ hybridization analysis showed a characteristic expression of the tob2 mRNA in oocytes, suggesting a unique role of Tob2 in oogenesis. Like the Tob protein, Tob2 inhibited cell cycle progression from the G0/G1 to S phases. Intriguingly, the amino-terminal half of Tob2 as well as that of Tob was associated with a human homologue of yeast Caf1, a component of the CCR4 transcription factor complex. Moreover, Caf1 was associated with cyclin dependent kinases. These data suggested that both Tob and Tob2 were involved in cell cycle regulation through their interaction with Caf1. Finally, the tob2 gene was mapped to human chromosome 22q13.1-q13.31.

Chitosan induces apoptosis via caspase-3 activation in bladder tumor cells

Recently, because of its low toxicity and biological effects, chitosan has been widely used in the medical and pharmaceutical fields, e.g., for nasal or oral delivery of peptide or polar drug delivery. Here, we report a growth-inhibitory effect of chitosan on tumor cells. The growth inhibition was examined by WST-1 colorimetric assay and cell counting. We also observed DNA fragmentation, which is characteristic of apoptosis, and elevated caspase-3-like activity in chitosan-treated cancer cells. The findings suggest that chitosan may have potential value in cancer therapy.

Urinary excretion of 8-oxo-7, 8-dihydro-2'-deoxyguanosine as a predictor of the development of diabetic nephropathy

AIMS/HYPOTHESIS

The increased oxidative stress in diabetes is known to contribute to the progression of diabetes and its complications. We have reported a significant relation between the content of 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG), a product of oxidative DNA damage in urine or leukocytes and the severity of diabetic nephropathy and retinopathy [1]. We investigated whether 8-oxodG in urine or leukocytes is associated with the progression of diabetic nephropathy.

METHODS

We measured urinary 8-oxodG contents at entry and carried out a prospective longitudinal study to assess the progression of nephropathy over 5 years.

RESULTS

There was a significant progression of diabetic nephropathy in the patients with higher excretion of 8-oxodG in urine compared with the patients with moderate or lower excretion of 8-oxodG. There was no significant association between the leukocyte 8-oxodG contents and the development of nephropathy. The multivariate logistic regression analysis suggests that the urinary 8-oxodG was the strongest predictor of nephropathy among several known risk factors.

CONCLUSION/INTERPRETATION

This study provides evidence that increased oxidative stress has a primary role in the pathogenesis of diabetic nephropathy. A local enhancement of oxidative stress in diabetic kidney might explain the possible linkage between the increased urinary excretion of 8-oxodG and the development of nephropathy. 8-oxodG in urine is a useful clinical marker to predict the development of diabetic nephropathy in diabetic patients.

Identification of two loci for resistance to clubroot (Plasmodiophora brassicae Woronin) in Brassica rapa L

In an analysis of 114 F(2) individuals from a cross between clubroot-resistant and susceptible lines of Brassica rapa L., 'G004' and 'Hakusai Chukanbohon Nou 7' (A9709), respectively, we identified two loci, Crr1 and Crr2, for clubroot (caused by Plasmodiophora brassicae Woronin) resistance. Each locus segregated independently among the F(2) population, indicating that the loci reside on a different region of chromosomes or on different chromosomes. Genetic analysis showed that each locus had little effect on clubroot resistance by itself, indicating that these two loci are complementary for clubroot resistance. The resistance to clubroot was much stronger when both loci were homozygous for resistant alleles than when they were heterozygous. These results indicate that clubroot resistance in B. rapa is under oligogenic control and at least two loci are necessary for resistance.

Distribution of cells containing progesterone receptor mRNA in the female rat di- and telencephalon: an in situ hybridization study

In an attempt to examine regional synthesis of the progesterone receptor (PR) in the brain, the distribution of mRNA encoding PR was investigated in the female adult rat di- and telencephalon by in situ hybridization using T7 RNA polymerase transcripts of a 320 base pair rat PR cDNA clone. The rat PR cDNA had been partially cloned and sequenced by using the reverse transcription-polymerase chain reaction (RT-PCR) method. The primer set corresponds to a part of the progesterone binding domain of human PR cDNA. Large numbers of strong labeling were observed in the arcuate nucleus, medial preoptic nucleus, and ventrolateral part of the ventromedial nucleus which are relative to sexual behavior. Moderate labeling was found in layers II and IV of the isocortex, in the pyramidal layer of the CA1 and CA3 fields of the hippocampal formation, in the cortical nucleus of the amygdala, in the nucleus of the diagonal band, and in the anterior periventricular nucleus. Weak labeling was found in many other regions. These results were largely in agreement with the distribution of PR previously reported by ligand binding assay and autoradiographic studies. This present in situ hybridization study may provide a useful tool for the analysis of the regional regulation of PR synthesis in the rat brain.

The genes degQ, pps, and lpa-8 (sfp) are responsible for conversion of Bacillus subtilis 168 to plipastatin production

Bacillus subtilis YB8 produces the lipopeptide antibiotic plipastatin. B. subtilis MI113, which is a derivative of strain 168, was converted into a new plipastatin producer, strain 406, by competence transformation with the chromosomal DNA of YB8. Transposon mini-Tn10 insertional mutagenesis was applied to strain 406, which revealed that lpa-8 (sfp) (encoding 4'-phosphopantetheinyl transferase) and the pps operon (located between 167 and 171 degrees ) are essential for plipastatin production. The pps operon was previously suggested to encode putative peptide synthetases (A. Tognoni, E. Franchi, C. Magistrelli, E. Colombo, P. Cosmina, and G. Grandi, Microbiology 141:645-648, 1995) and was thought to be the fengycin operon (V. Tosato, A. M. Albertini, M. Zotti, S. Sonda, and C. V. Bruschi, Microbiology 143:3443-3450, 1997). We claim that the pps operon is the pli operon, encoding plipastatin synthetase. By using a new high-performance liquid chromatography system, we revealed that strain 168 expressing only lpa-8 can also produce plipastatin, although the yield is very low. However, the introduction of the pleiotropic regulator degQ of strain YB8 into strain 168 expressing lpa-8 resulted in a 10-fold increase in the production of plipastatin.

Expression of vascular endothelial growth factors (VEGF-A/VEGF-1 and VEGF-C/VEGF-2) in postmenopausal uterine endometrial carcinoma

OBJECTIVE

We investigated the expression of two angiogenic vascular endothelial growth factors, VEGF-A/VEGF-1 and VEGF-C/VEGF-2, in 228 cases of uterine endometrial carcinomas from postmenopausal patients to evaluate the correlation with histopathologic features and clinical outcome.

METHODS

Immunohistochemistry was used to assess VEGF-A/VEGF-1 and VEGF-C/VEGF-2 expression in 228 primary surgically treated cases of postmenopausal endometrial carcinomas and the results were statistically analyzed in relation to vascular invasion, depth of invasion (myometrial vs serosal-parametrial invasion), lymphatic vessel invasion, lymph node metastasis, disease-free 5-year survival rate (DF5YR), and disease-free 10 year-survival rate (DF10YR).

RESULTS

The results of univariate analysis showed that VEGF-A/VEGF-1 and VEGF-C/VEGF-2 expression correlated with vascular invasion (P < 0.0001, P = 0.0006), depth of invasion (P = 0.0004, P = 0.043), lymphatic vessel invasion (P = 0.021, P < 0.0001), lymph node metastasis (P = 0.0017, P = 0.0008), DF5YR (P = 0.0081, P = 0.0002), and DF10YR (P = 0.0077, P = 0.0001). Multivariate analysis showed that lymph node metastasis (P = 0.0017, P = 0.0008), parametrial-serosal invasion (P < 0.0001, P < 0.0001), and VEGF-C/VEGF-2-positive status (P = 0.03, P = 0.01) were significant factors in DF5YR and DF10YR.

CONCLUSIONS

We conclude that VEGF-A/VEGF-1 and VEGF-C/VEGF-2 expression was predictive of these histopathologic features of endometrial carcinoma and clinical outcome.

Mapping and characterization of FLC homologs and QTL analysis of flowering time in Brassica oleracea

The FLC gene product is an inhibitor of flowering in Arabidopsis. FLC homologs in Brassica species are thought to control vernalization. We cloned four FLC homologs (BoFLCs) from Brassica oleracea. Three of these, BoFLC1, BoFLC3 and BoFLC5, have been previously characterized. The fourth novel sequence displayed 98% sequence homology to the previously identified gene BoFLC4, but also showed 91% homology to BrFLC2 from Brassica rapa. Phylogenetic analysis showed that this clone belongs to the FLC2 clade. Therefore, we designated this gene BoFLC2. Based on the segregation of RFLP, SRAP, CAPS, SSR and AFLP loci, a detailed linkage map of B. oleracea was constructed in the F(2) progeny obtained from a cross of B. oleracea cv. Green Comet (broccoli; non-vernalization type) and B. oleracea cv. Reiho (cabbage; vernalization type), which covered 540 cM, 9 major linkage groups. Six quantitative trait loci (QTL) controlling flowering time were detected. BoFLC1, BoFLC3 and BoFLC5 were not linked to the QTLs controlling flowering time. However, the largest QTL effect was located in the region where BoFLC2 was mapped. Genotyping of F(2 )plants at the BoFLC2 locus showed that most of the early flowering plants were homozygotes of BoFLC-GC, whereas most of the late- and non-flowering plants were homozygotes of BoFLC-Rei. The BoFLC2 homologs present in plants of the non-vernalization type were non-functional, due to a frameshift in exon 4. Moreover, duplications and deletions of BoFLC2 were detected in broccoli and a rapid cycling line, respectively. These results suggest that BoFLC2 contributes to the control of flowering time in B. oleracea.

The complete primary structure of calcineurin A, a calmodulin binding protein homologous with protein phosphatases 1 and 2A

A complementary DNA (cDNA) clone encoding the catalytic subunit of calcineurin (calcineurin A) has been isolated from a rat brain cDNA library. The primary structure of the cDNA consists of 2,337 nucleotides including the entire coding region for 521 amino acids, and the calculated molecular mass is 58,643 Da. The calcineurin A is strikingly homologous to protein phosphatases 1 and 2A, approximately 50% of the amino acids over an internal 250-residue region between residues 78 and 329 being identical. Twenty four amino acid-residue region between residues 391 and 414 shows the consensus structural features for a calmodulin-binding domain. These data suggest that the allosteric character of this chimeric enzyme is generated by gene fusion of two separate protein families.

Oxidative damage to mitochondrial DNA and its relationship to diabetic complications

Increased oxidative stress induced by hyperglycemia may contribute to the pathogenesis of diabetic complications. Oxidative stress is known to increase the conversion of deoxyguanosine (dG) to 8-hydroxydeoxyguanosine (8-OHdG) in DNA, which is linked to increased mitochondrial DNA (mtDNA) deletions. We investigated mtDNA deletions and 8-OHdG in the muscle DNA of non-insulin-dependent diabetes mellitus (NIDDM) patients. mtDNA deletion of 4977 bp (delta mtDNA4977) and the content of 8-OHdG in the muscle DNA of the NIDDM patients were much higher than those of the control subjects. There was a significant correlation between delta mtDNA4977 and the 8-OHdG content (P < 0.0001). Both delta mtDNA4977 and the 8-OHdG content were also correlated with the duration of diabetes. Delta mtDNA4977 and the 8-OHdG content in muscle DNA increased in proportion to the severity of diabetic nephropathy and retinopathy. This is the first report that an increase in delta mtDNA4977 and 8-OHdG is proportional to the severity of diabetic complications. Oxidative mtDNA damage is speculated to contribute to the pathogenesis of diabetic complications though a defect in mitochondrial oxidative phosphorylation or other mechanisms. 8-OHdG and delta mtDNA4977 are useful markers to evaluate oxidative mtDNA damage in the diabetic patients.

A novel locus for clubroot resistance in Brassica rapa and its linkage markers

An inbred turnip ( Brassica rapa syn. campestris) line, N-WMR-3, which carries the trait of clubroot resistance (CR) from a European turnip, Milan White, was crossed with a clubroot-susceptible doubled haploid line, A9709. A segregating F(3) population was obtained by single-seed descent of F(2) plants and used for a genetic analysis. Segregation of CR in the F(3) population suggested that CR is controlled by a major gene. Two RAPD markers, OPC11-1 and OPC11-2, were obtained as candidates of linkage markers by bulked segregant analysis. These were converted to sequence-tagged site markers, by cloning and sequencing of the polymorphic bands, and named OPC11-1S and OPC11-2S, respectively. The specific primer pairs for OPC11-1S amplified a clear dominant band, while the primer pairs for OPC11-2S resulted in co-dominant bands. Frequency distributions and statistical analyses indicate the presence of a major dominant CR gene linked to these two markers. The present marker for CR was independent of the previously found CR loci, Crr1 and Crr2. Genotypic distribution and statistical analyses did not show any evidence of CR alleles on Crr1 and Crr2 loci in N-WMR-3. The present study clearly demonstrates that B. rapa has at least three CR loci. Therefore, the new CR locus was named Crr3. The present locus may be useful in breeding CR Chinese cabbage cultivars to overcome the decay of present CR cultivars.

The effects of coenzyme Q10 treatment on maternally inherited diabetes mellitus and deafness, and mitochondrial DNA 3243 (A to G) mutation

The characteristic clinical features of diabetes mellitus with mitochondrial DNA (mtDNA) 3243(A-G) mutation are progressive insulin secretory defect, neurosensory deafness and maternal inheritance, referred to as maternally inherited diabetes mellitus and deafness (MIDD). A treatment for MIDD to improve insulin secretory defects and reduce deafness has not been established. The effects of coenzyme Q10 (CoQ10) treatment on insulin secretory response, hearing capacity and clinical symptoms of MIDD were investigated. 28 MIDD patients (CoQ10-DM), 7 mutant subjects with impaired glucose tolerance (IGT), and 15 mutant subjects with normal glucose tolerance (NGT) were treated daily with oral administration of 150 mg of CoQ10 for 3 years. Insulin secretory response, blood lactate after exercise, hearing capacity and other laboratory examinations were investigated every year. In the same way we evaluated 16 MIDD patients (control-DM), 5 mutant IGT and 5 mutant NGT subjects in yearly examinations. The insulin secretory response assessed by glucagon-induced C-peptide secretion and 24 h urinary C-peptide excretion after 3 years in the CoQ10-DM group was significantly higher than that in the control-DM group. CoQ10 therapy prevented progressive hearing loss and improved blood lactate after exercise in the MIDD patients. CoQ10 treatment did not affect the diabetic complications or other clinical symptoms of MIDD patients. CoQ10 treatment did not affect the insulin secretory capacity of the mutant IGT and NGT subjects. There were no side effects during therapy. This is the first report demonstrating the therapeutic usefulness of CoQ10 on MIDD.

cDNA cloning, expression and characterization of nitric-oxide synthase from the salivary glands of the blood-sucking insect Rhodnius prolixus

Rhodnius prolixus, a blood-sucking bug, is a unique insect that is known to produce nitric oxide (NO) in the salivary glands to use as a vasodilator for blood sucking. We report here the cloning of the NO synthase (NOS) cDNA from these salivary glands and its expression in a baculovirus system. This cDNA encodes a protein of 1174 amino acids with a calculated molecular mass of 132,331 Da. The primary structures of mammalian NOS, including the putative cofactor-recognition sites for heme, tetrahydrobiopterin (BH4), calmodulin. FMN, FAD and NADPH are all conserved in salivary-gland NOS. Recombinant salivary-gland NOS differed from nerve NOS and endothelial NOS in that it lacked a large N-terminal domain and an N-terminal myristylation sequence, respectively. Salivary-gland NOS produced in a baculovirus system showed NOS activity and demonstrated that salivary-gland NOS was soluble and was Ca2+ and calmodulin dependent, similarly to mammalian constitutive NOS isoforms. Recombinant salivary-gland NOS was purified to near homogeneity and migrated at 130 kDa on SDS/PAGE.

Screening for imprinted genes by allelic message display: identification of a paternally expressed gene impact on mouse chromosome 18

A systematic screen termed the allelic message display (AMD) was developed for the hunting of imprinted genes. In AMD, differential display PCR is adopted to image allelic expression status of multiple polymorphic transcripts in two parental mouse strains, reciprocal F1 hybrids and pooled backcross progenies. From the displayed patterns, paternally and maternally expressed transcripts can be unequivocally identified. The effectiveness of AMD screening was clearly demonstrated by the identification of a paternally expressed gene Impact on mouse chromosome 18, the predicted product of which belongs to the YCR59c/yigZ hypothetical protein family composed of yeast and bacterial proteins with currently unknown function. In contrast with previous screening methods necessitating positional cloning efforts or generation of parthenogenetic embryos, this approach requires nothing particular but appropriately crossed mice and can be readily applied to any tissues at various developmental stages. Hence, AMD would considerably accelerate the identification of imprinted genes playing pivotal roles in mammalian development and the pathogenesis of various diseases.