Biomedical subjects

Hiroshi Yokota

Publications and source records attributed to Hiroshi Yokota.

At least 19 recordsLinked to original sources

PubMed2007

Synaptotagmin XI as a candidate gene for susceptibility to schizophrenia.

Synaptotagmin XI (Syt11) is a member of the synaptotagmin family, which is localized in cells either in synaptic vesicles or the cellular membrane, and is known to act as a calcium sensor. The Syt11 gene is located on chromosome locus 1q21-q22, which was previously reported as a major susceptibility locus of familial schizophrenia. Here, we present evidence for an association between the number of 33-bp repeats in the promoter region of the Syt11 gene and schizophrenia. We found that the transcriptional activity of the gene is affected by the number of 33-bp repeats, which include an Sp1 binding site, suggesting that the excessive expression of Syt11 can be associated with schizophrenia. Another (single nucleotide) polymorphism in the Syt11 5'UTR region, where the potent transcription factor YY1 can bind, also affects the transcriptional activity of Syt11.

Base Sequence↗

PubMed2007

Spinal cord herniation into associated pseudomeningocele after brachial plexus avulsion injury: case report.

OBJECTIVE: Posttraumatic spinal cord herniation is a rare condition. We describe a case of spinal cord herniation into an associated pseudomeningocele after a brachial plexus avulsion injury. CLINICAL PRESENTATION: A 33-year-old man began to develop progressive Horner's syndrome 14 years after a brachial plexus avulsion injury. At a clinical presentation 17 years after that injury, sensory disturbance and a unilateral pyramidal sign were also evident. In addition to myelography and computed tomographic myelography findings, coronal magnetic resonance imaging scans clearly demonstrated herniation of the spinal cord into a large pseudomeningocele inside the C7-T1 intervertebral foramen. Another pseudomeningocele inside the T1-T2 intervertebral foramen was also noted. INTERVENTION: The patient underwent a C6-T2 laminectomy, during which the spinal cord was found to be herniated through a dural defect into a pseudomeningocele at the C8 root level, and a second dural defect was also shown, with an arachnoid outpouching that included an avulsed T1 root. The spinal cord herniation was reduced and the dural defects were repaired. After surgery, the patient showed no significant neurological changes, and his condition stabilized. CONCLUSION: Brachial plexus root avulsions may result in the formation of pseudomeningoceles and can lead to spinal cord herniation. Coronal magnetic resonance imaging is useful to demonstrate spinal cord herniation as well as pseudomeningoceles. Surgical treatment is recommended for such cases with progressive symptoms to prevent further deterioration.

Adult↗

PubMed2006

cDNA cloning and characterization of feline CYP1A1 and CYP1A2.

Deficiency of drug glucuronidation in the cat is one of the major reasons why this animal is highly sensitive to the side effects of drugs. The characterization of cytochrome P450 isoforms belonging to the CYP1A subfamily, which exhibit important drug oxidation activities such as activation of pro-carcinogens, was investigated. Two cDNAs, designated CYP1A-a and CYP1A-b, corresponding to the CYP1A subfamily were obtained from feline liver. CYP1A-a and CYP1A-b cDNAs comprise coding regions of 1554 bp and 1539 bp, and encode predicted amino acid sequences of 517 and 512 residues, respectively. These amino acid sequences contain a heme-binding cysteine and a conserved threonine. The cDNA identities, as well as the predicted amino acid sequences containing six substrate recognition sites, suggest that CYP1A-a and CYP1A-b correspond to CYP1A1 and CYP1A2, respectively. This was confirmed by the kinetic parameters of the arylhydrocarbon hydroxylase and 7-ethoxyresorufin O-deethylase activities of expressed CYPs in yeast AH22 cells and by the tissue distribution of each mRNA. However, theophylline 3-demethylation is believed to be catalyzed by CYP1A1 in cats, based on the high V(max) and low K(m) seen, in contrast to other animals. Because feline CYP1A2 had a higher K(m) for phenacetin O-deethylase activity with acetaminophen, which cannot be conjugated with glucuronic acid due to UDP-glucuronosyltransferase deficiency, it is supposed that the side effects of phenacetin as a result of toxic intermediates are severe and prolonged in cats.

Amino Acid Sequence↗

PubMed2006

Monocarboxylate transporter 1 (MCT1) plays a direct role in short-chain fatty acids absorption in caprine rumen.

Despite the importance of short-chain fatty acids (SCFA) in maintaining the ruminant physiology, the mechanism of SCFA absorption is still not fully studied. The goal of this study was to elucidate the possible involvement of monocarboxylate transporter 1 (MCT1) in the mechanism of SCFA transport in the caprine rumen, and to delineate the precise cellular localization and the level of MCT1 protein along the entire caprine gastrointestinal tract. RT-PCR revealed the presence of mRNA encoding for MCT1 in all regions of the caprine gastrointestinal tract. Quantitative Western blot analysis showed that the level of MCT1 protein was in the order of rumen >/= reticulum > omasum > caecum > proximal colon > distal colon > abomasum > small intestine. Immunohistochemistry and immunofluorescence confocal analyses revealed widespread immunoreactive positivities for MCT1 in the caprine stomach and large intestine. Amongst the stratified squamous epithelial cells of the forestomach, MCT1 was predominantly expressed on the cell boundaries of the stratum basale and stratum spinosum. Double-immunofluorescence confocal laser-scanning microscopy confirmed the co-localization of MCT1 with its ancillary protein, CD147 in the caprine gastrointestinal tract. In vivo and in vitro functional studies, under the influence of the MCT1 inhibitors, p-chloromercuribenzoate (pCMB) and p-chloromercuribenzoic acid (pCMBA), demonstrated significant inhibitory effect on acetate and propionate transport in the rumen. This study provides evidence, for the first time in ruminants, that MCT1 has a direct role in the transepithelial transport and efflux of the SCFA across the stratum spinosum and stratum basale of the forestomach toward the blood side.

Amino Acid Sequence↗

PubMed2006

A novel membrane protein, encoded by the gene covering KIAA0233, is transcriptionally induced in senile plaque-associated astrocytes.

Beta-amyloid (Abeta) deposition and senile plaque-associated astrocytes are common neuropathological features of Alzheimer's disease (AD). Although the molecular mechanisms by which Abeta contributes to the progression of neuropathologic changes have not been entirely established, there is little doubt that the association of Abeta with astrocytes, the predominant cell type in brain, significantly influences exacerbation of the disease. In an effort to identify astrocyte-derived molecules that may be intimately associated with progression of AD, we identified a novel Abeta-induced rat gene, designated Mib, whose human counterpart covers KIAA0233. Mib-transfected C6 cells express Mib protein in the endoplasmic reticulum and endplasmic reticulum-Golgi-intermediate compartment. To evaluate roles of Mib in AD, we investigated its expression in the AD brain. In non-AD brains, Mib mRNA has been detected in neurons but not in quiescent astrocytes. On the contrary, in AD brains, Mib mRNA is expressed in activated astrocytes associated with senile plaques, but not expressed in neurons around lesions. From these observations, Mib appears to be a novel Abeta-responsive gene that may play a role in astrocyte inflammatory activation around senile plaques in the AD brain.

Alzheimer Disease↗

PubMed2006

Down regulation of bisphenol A glucuronidation in carp during the winter pre-breeding season.

Environmental pollution by bisphenol A is prevalent in many rivers. The influence of bisphenol A on the reproductive organs of carp has been demonstrated to be serious, especially in the winter pre-breeding season. Although bisphenol A is detoxified as bisphenol A-glucuronide in carp organs, principally the intestine, the seasonal variation in the efficiency of the detoxification is not known. To estimate the seasonal risk of bisphenol A in carp, we investigated seasonal changes in microsomal UDP-glucuronosyltransferase activity toward bisphenol A in male-carp. Seasonal elimination efficiency of bisphenol A was also examined by organ perfusion in everted intestine. No marked seasonal differences were observed in UDP-glucuronosyltransferase activity toward 1-naphthol, but high activity toward sex steroid hormones (testosterone and estradiol) was observed in the winter pre-breeding season. Low UDP-glucuronosyltransferase activity toward bisphenol A was indicated in winter. The addition of bisphenol A into the mucosal fluid of the everted intestine resulted in excretion of bisphenol A into the mucosal side of the intestine as the metabolite, bisphenol A-glucuronide. Excretion of bisphenol A-glucuronide from carp intestine was highest in summer (proximal intestine: 13.3 nmol; middle intestine: 8.3 nmol; distal intestine: 7.9 nmol) and lowest in winter (proximal intestine: 1.0 nmol; middle intestine: 1.0 nmol; distal intestine: 0.9 nmol). These results suggest that metabolism and excretion of bisphenol A in carp hepatopancreas and intestine are impaired by down regulation of UDP-glucuronosyltransferase activity in the winter pre-breeding season.

Animals↗

PubMed2006

Expression of the PTEN tumor suppressor gene in malignant mammary gland tumors of dogs.

OBJECTIVE: To determine whether changes in expression level of the phosphatase and tensin homolog deleted on the chromosome 10 (PTEN) gene are associated with malignant transformation in mammary gland tumors in dogs. SAMPLE POPULATION: Specimens of 5 benign and 8 malignant mammary gland tumors and 2 unaffected mammary glands from dogs. PROCEDURE: The open reading frame (ORF) sequence of PTEN gene in each specimen was analyzed via a direct-sequencing method; expression levels of PTEN gene were quantified via a competitive reverse transcription (RT)-PCR method. RESULTS: Compared with findings in clinically normal samples, amounts of PTEN mRNA were increased 2- to 4-fold in 4 of the 5 benign mammary gland tumor samples. In contrast, PTEN expression was remarkably low in 4 of the 8 malignant tumor samples (approx 12% to 37% of the level in unaffected mammary gland specimens). Gene amplification via the RT-PCR method with total RNA prepared from malignant tumor samples as a template yielded 3 bands that were smaller than the full-length ORF product of PTEN gene; in 2 of those 3 RT-PCR products, exons 6 and 7 or exons 3 to 8 were absent. No mutation was detected in the full-length ORF product of PTEN gene. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that a decreased level of PTEN gene expression (compared with unaffected mammary gland tissue) is associated with malignancy in canine mammary tumors. Analysis of PTENgene expression level in dogs with mammary gland tumors may provide useful prognostic information.

Age Factors↗

PubMed2006

Persistent intracranial hypertension caused by superior sagittal sinus stenosis following depressed skull fracture. Case report and review of the literature.

Intracranial hypertension caused by a compound depressed skull fracture on the posterior part of the superior sagittal sinus is a rare condition, and nonspecific symptoms and signs can delay appropriate diagnosis and treatment. The authors report on a case of intracranial hypertension that persisted despite conservative treatment, including anticoagulation therapy, which did not improve severe flow disturbance related to the venous sinus compression. Management of this rare condition is discussed and the literature is reviewed.

Anticoagulants↗

PubMed2006

[Anesthesic management of a patient with Stickler's syndrome].

Stickler's syndrome is a connective-tissue disease of autosome dominant inheritance. This report concerns a 3-year-old girl with Stickler's syndrome who underwent arthroplasty under general anesthesia. After slow induction of anesthesia with an inhalation anesthetic, neither a oropharyngeal airway nor a laryngeal mask airway fitted her, and mask ventilation and endotracheal intubation became difficult. Endotracheal intubation was performed not with a muscle relaxant but under deep anesthesia. Care should be taken when planning anesthesia for a case of this syndrome because airway management is often difficult and emergency surgery for detached retinas might be required.

Anesthesia, General↗

PubMed2005

Slow elimination of nonylphenol from rat intestine.

Nonylphenol, a possible endocrine disrupter, tends to persist in rat liver tissue after detoxification as a glucuronide conjugate by UDP-glucuronosyltransferase 2B1 expressed in the liver. In the intestine, however, the metabolism and dynamics of nonylphenol remain to be elucidated. The objectives of this study were to clarify the metabolism and excretion of nonylphenol having a long alkyl chain in the first barrier intestine and to estimate whether the nonylphenol alkyl chain governs the speed of excretion from intestinal tissue. Organ tissue glucuronidation activity toward alkylphenols (C2, C9) was investigated using microsomes prepared from intestinal tissue. To elucidate the elimination pathway of alkylphenols (C2, C4, C6, C9), a perfusion study was conducted on everted intestine. After oral administration (5 mg) of alkylphenols (C2, C9) to rats, gastrointestinal contents and related organ tissues (gastrointestinal tissue, liver, and kidney), blood, and urine were analyzed for alkylphenols (C2, C9) and glucuronides. The intestine showed strong glucuronidation activity toward alkylphenols (C2, C9). In everted intestinal assay, nonylphenol was glucuronidated within the intestinal wall, as was the case for other alkylphenols (C2, C4, C6), but nonylphenol-glucuronide was not excreted from intestinal tissue. Orally administered nonylphenol remained for long periods in gastrointestinal tissue as both the parent compound and glucuronide. The present study confirmed that intestinal tissue possesses an alkylphenol elimination system using UDP-glucuronosyltransferase; however, this system is impaired by the marginal transport of alkylphenol-glucuronide possessing long alkyl chain, such as nonylphenol.

Administration, Oral↗

PubMed2005

Lib, transcriptionally induced in senile plaque-associated astrocytes, promotes glial migration through extracellular matrix.

In an effort to identify astrocyte-derived molecules that may be intimately associated with progression of Alzheimer's disease (AD), Lib, a type I transmembrane protein belonging to leucine-rich repeat superfamily, has been identified as a distinctly inducible gene, responsive to beta-amyloid as well as pro-inflammatory cytokines in astrocytes. To evaluate the roles of Lib in AD, we investigated Lib expression in AD brain. In non-AD brain, Lib mRNA has been detected in neurons but not in quiescent astrocytes. On the contrary, in AD brain, Lib mRNA is expressed in activated astrocytes associated with senile plaques, but not expressed in neurons around lesions. Lib-expressing glioma cells displayed promotion of migration ability through reconstituted extracellular matrix and recombinant Lib protein bound to constituents of extracellular matrix. These observations suggest that Lib may contribute to regulation of cell-matrix adhesion interactions with respect to astrocyte recruitment around senile plaques in AD brain.

Aged↗

PubMed2005

Cytochrome P450 2E polymorphism in feline liver.

Only one isoform of cytochrome P450 (CYP) 2E subfamily was known in human and various animals. Three cDNAs corresponding to CYP 2E subfamily members (CYP2E-a, CYP2E-b and CYP2E-c) were obtained from feline liver. These cDNAs each had a 1488-bp nucleotide coding region encoding a predicted amino acid sequence of 495 residues. Eleven amino acid substitutions were observed between CYP2E-a and CYP2E-b, but only one substitution between CYP2E-b and CYP2E-c. The CO difference spectrums about 450 nm wave length and similar values of Vmax and Km of 6-hydoxygenase activity toward chlorzoxazone were observed in all three isoforms expressed in AH22 yeast cells. By PCR-RFLP, mRNA of the CYP2E-a was found to be expressed in liver, mononuclear cells, kidney, lung, stomach, intestine and pancreas, whereas CYP2E-b and CYP2E-c were expressed mainly in the liver and mononuclear cells. Expression of CYP2E-a was observed in the livers of all felines tested, but CYP2E-b and CYP2E-c were not expressed in all cats. The sequences of two different introns between exons I and II and between exons VII and VIII were obtained in genomic DNA from the feline liver. Based on these results, we conclude that cats have two highly similar CYP2E genes.

Amino Acid Sequence↗

PubMed2005

Stir bar sorptive extraction with in situ de-conjugation and thermal desorption gas chromatography-mass spectrometry for measurement of 4-nonylphenol glucuronide in human urine sample.

4-Nonylphenol glucuronide (NP-G) in human urine samples was analyzed using stir bar sorptive extraction (SBSE) with in situ de-conjugation by beta-glucuronidase and thermal desorption (TD)-gas chromatography-mass spectrometry (GC-MS). Distilled water (1 ml), 1.0 M ammonium acetate solution (100 microl) and beta-glucuronidase (10,000 units ml(-1), 10 microl) were added to human urine sample (1 ml), and extraction was commenced for 90 min at 37 degrees C while stirring at 250 rpm with a stir bar coated with a 500-microm-thick polydimethylsiloxane (PDMS) layer. Then, the stir bar was subjected to TD-GC-MS in the selected ion monitoring (SIM) mode. The calibration curve was made by SBSE method using 4-nonylphenol (NP) as the standard solution. The method showed good linearity and the correlation coefficients were 0.999 over the concentration range of 5-500 nM. Moreover, to optimize the conditions for SBSE with in situ de-conjugation and the recovery test, NP-G was synthesized by a biochemical technique in our laboratory. The limits of detection (S/N = 3) and quantitation (S/N > 10) for NP were 0.2 ng ml(-1) (1.0 nM) and 1.1 ng ml(-1) (5.0 nM), respectively. The average recoveries in the human urine samples (n = 6) spiked with NP-G at levels of 20 and 100 nM were 104.1 (R.S.D. 7.1%) and 100.6% (R.S.D. 9.2%), respectively, with correction using the added internal standard, 4-(1-methyl) octylphenol-d(5). The method enabled the precise determination of the standard and was applicable to the detection of trace amounts of NP-G in human urine samples.

Acetates↗

PubMed2005

UDP-glucuronosyltransferase isoforms catalyzing glucuronidation of hydroxy-polychlorinated biphenyls in rat.

Polychlorinated biphenyls (PCBs) are highly toxic environmental contaminants that can cause irreversible damage in humans and wildlife. The mechanism of toxicity is not clear, but biotransformation products such as hydroxy PCBs (OH-PCBs) are a major concern. Efforts to elucidate the metabolism of PCBs and their metabolites, however, have paid little attention to the structure of the compound to be eliminated. The objectives of this study were to clarify organ tissue distribution of the glucuronidation activities toward OH-PCBs and to determine the UDP-glucuronosyltranseferase (UGT) isoforms responsible for glucuronidation in relation to the OH-PCB structure. 2,4,6-Trichlorobiphenyl and 2,3,4,5-tetrachlorobiphenyl were incubated in primary culture of rat hepatocytes, and the metabolites were identified by HPLC. Organ tissue glucuronidation activities toward 10 OH-PCBs were investigated by reactions of microsomes prepared from brain, liver, small and large intestine, lung, kidney, and testis tissues. To determine substrate specificity of the isoforms toward the OH-PCBs, rat UGT isoforms UGT1A1, UGT1A3, UGT1A5, UGT1A6, UGT1A7, UGT2B1, UGT2B3, and UGT2B12 were expressed in yeast strain AH22. Glucuronidation of the PCBs was found to be contingent on their hydroxylation. The organ tissues had strong glucuronidation activities toward the OH-PCBs tested; and most OH-PCBs were glucuronidated by UGT1A1, UGT1A6, and UGT2B1, all of which were substrate-specific. In conclusion, glucuronidation activities of UGT1A1, UGT1A6, and UGT2B1 toward OH-PCBs is relative to expression of the isoforms in each tissue, and glucuronidation intensity of the isoforms is relative to the structure of the OH-PCB to be glucuronidated.

Animals↗

PubMed2005

Isoform-specific expression and induction of udp-glucuronosyltransferase in immunoactivated peritoneal macrophages of the rat.

Phase I drug-metabolizing enzymes such as cytochrome P450 in immunocytes are known to play a role in metabolic activation of toxic and immunosuppressive compounds such as polycyclic aromatic hydrocarbon (PAH). UDP-glucuronosyltransferase (UGT), a drug-metabolizing phase II enzyme, accelerates elimination of these compounds; however, there is little information on the expression and function of UGT in immunocytes. In this study, we investigated the expressions of UGT isoforms in rat peritoneal macrophages and the role of UGT in macrophage functions. Expressions of UGT1A1, 1A6, and 1A7 were observed in macrophages by immunohistochemical staining and reverse transcriptase-polymerase chain reaction. When macrophage cells cultured in plates were exposed to 1-naphthol and 3-hydroxybenzo-[a]pyrene (3-OH-B[a]P), these glucuronides increased in the medium, indicating that macrophages glucuronidated the chemicals. The production of the glucuronides of 1-naphthol and 3-OH-B[a]P was induced by lipopolysaccharide (LPS) treatment of the cultured macrophage cells. Northern blot analysis revealed that UGT1A7 mRNA was induced by LPS treatment. This result is the first evidence that a drug-metabolizing enzyme is induced by immunoactivation. The results indicated that macrophages can detoxify various toxic and immunosuppressive compounds with UGT, and that ability is enhanced by immunoactivation. We propose that macrophages contribute to protection against not only macromolecules as immunocytes but also small molecules such as the immunosuppressive agents PAHs in peripheral blood and interstitial tissues.

Animals↗

PubMed2005

Direct determination of peracetic acid, hydrogen peroxide, and acetic acid in disinfectant solutions by far-ultraviolet absorption spectroscopy.

In this paper we propose a rapid and highly selective far-ultraviolet (FUV) spectroscopic method for the simultaneous determination of peracetic acid (PAA), hydrogen peroxide, and acetic acid (AA). For this purpose we developed a novel FUV spectrometer that enables us to measure the spectra down to 180 nm. Direct determination of PAA, H(2)O(2), and AA, the three main species in disinfectant solutions, was carried out by using their absorption bands in the 180-220-nm region. The proposed method does not require any reagents or catalysts, a calibration standard, and a complicated procedure for the analysis. The only preparation procedure requested is a dilution of H(2)O(2) with pure water to a concentration range lower than 0.2 wt % in the sample solutions. Usually, the required concentration range can be obtained by the 10 times volume dilution of the actual disinfectant solutions. As the measured sample does not leave any impurity for the disinfection, it can be reused completely by using a circulation system. The detection limit for PAA of the new FUV spectrometer was evaluated to be 0.002 wt %, and the dynamic ranges of the measured concentrations were from 0 to 0.05 wt %, from 0 to 0.2 wt %, and from 0 to 0.2 wt % for PAA, H(2)O(2), and AA, respectively. The response time for the simultaneous determination of the three species is 30 s, and the analysis is applicable even to the flowing samples. This method may become a novel approach for the continuous monitoring of PAA in disinfectant solutions on the process of sterilization.

Acetic Acid↗

PubMed2005

Expression of ciliary neurotrophic factor (CNTF), CNTF receptor alpha (CNTFR-alpha) following experimental intracerebral hemorrhage in rats.

Ciliary neurotrophic factor (CNTF) is known as a neuro-survival factor in the developing and developed CNS, as well as in the CNS following injury. However, little is known about the expression of CNTF or that of its receptor (CNTFR-alpha) in cases of intracerebral hemorrhage (ICH). We investigated the temporal and spatial profiles of CNTF and CNTFR-alpha expression using a collagenase-induced ICH rat model. CNTF expression was up-regulated from the day following ICH induction and reached a peak level at 5 to 14 days, with increased expression observed in brain tissue surrounding the hematoma lesion and white matter structures in association with astroglial proliferation. Further, CNTFR-alpha was transiently expressed in the cerebral cortex surrounding the hematoma, with a peak at 5 days. Administration of exogenous CNTF into the lesion following initiation of ICH resulted in a prolonged expression of CNTFR-alpha on cortical neurons neighboring the hematoma. Our findings suggest differential regulation of CNTF and CNTFR-alpha, and the possibility of a therapeutic strategy using CNTF administration for ICH.

Animals↗

PubMed2005

Movement and fixation of intestinal microbiota after administration of human feces to germfree mice.

Human flora-associated (HFA) mice have been considered a tool for studying the ecology and metabolism of intestinal bacteria in humans, although they have some limitations as a model. Shifts in dominant species of microbiota in HFA mice after the administration of human intestinal microbiota was revealed by 16S rRNA gene sequence and terminal restriction fragment length polymorphism (T-RFLP) analyses. Characteristic terminal restriction fragments (T-RFs) were quantified as the proportion of total peak area of all T-RFs. Only the proportion of the T-RF peak at bp 366, identified as the Gammmaproteobacteria group and the family Coriobacteriaceae, was reduced in this study. Increased T-RFs over time at bp 56, 184, and 196 were affiliated with the Clostridium group. However, most of the isolated bacteria with unique population shifts were phylotypes. The vertical transmission of the intestinal microbiota of the mouse offspring was also investigated by dendrogram analysis derived from the similarity of T-RFLP patterns among samples. As a result, the intestinal microbiota of HFA mice and their offspring reflected the composition of individual human intestinal bacteria with some modifications. Moreover, we revealed that human-derived lactobacilli (HDL), which have been considered difficult to colonize in the HFA mouse intestine in previous studies based on culture methods, could be detected in the HFA mouse intestine by using a lactic acid bacterium-specific primer and HDL-specific primers. Our results indicate that the intestinal microbiota of HFA mice represents a limited sample of bacteria from the human source and are selected by unknown interactions between the host and bacteria.

Animals↗