Biomedical subjects

Jun Sakai

Publications and source records attributed to Jun Sakai.

14 recordsLinked to original sources

PubMed2007

Two-dimensional differential gel electrophoresis of rat heart proteins in ischemia and ischemia-reperfusion.

Ischemia-reperfusion injury occurs in acute myocardial infarction, cardiopulmonary bypass surgery, and heart transplantation. However the precise mechanisms still remain unclear. In order to identify proteins that are involved in ischemia-reperfusion injury, we compared precipitated 100,000g fractions of normal, ischemic, and ischemic-reperfused rat hearts using two-dimensional (2D) difference gel electrophoresis (2D-DIGE). 2D-DIGE is reliable method to define quantitative protein differences, especially when subtle protein changes are under investigation. In this study, six spots that changed more than twofold and two additional spots related to these spots were detected. Five of the spots were identified by matrix-assisted laser desorption/ionization time of flight mass spectrometry as protein disulfide isomerase, one as 60 kDa heat-shock protein, and two as elongation factor Tu.

Animals↗

PubMed2006

The relationship between bedding and face-down death in infancy: mathematical analysis of a respiratory simulation system using an infant mannequin to assess gas diffusibility in bedding.

Rebreathing is a model for the relationship between a prone sleeping position and sudden infant death syndrome. This study used a mechanical simulation model to establish the relationship between types of bedding and rebreathing potential for an infant placed prone (face down) at different postnatal ages. The infant mannequin was connected to a respirator set to deliver physiologically appropriate combinations of tidal volume (V(T)) and respiratory rates (RR) across a range of postnatal ages (0-18 months). Before measurements were made, CO(2) flow was regulated to 5+/-0.1% of end-tidal PCO(2) (EtCO(2)). After the model was placed in a prone position, any increase in the fractional concentration of inspired CO(2) (FiCO(2)) was measured. FiCO(2) increased immediately and rapidly, and reached a maximum value within a few minutes. The maximum FiCO(2) ranged from under 2% to over 10%, depending on the bedding. FiCO(2) was also affected by V(T) and RR. This model is not applicable to actual infants because of the large tissue stores of CO(2) in infants; however, it is useful for evaluation of gas diffusibility of bedding and will simplify the investigation of sleeping environments when a baby is found dead with its face covered by soft bedding. In general, the higher the FiCO(2), the greater the rebreathing potential. Theoretically, considering the paucity of body stores of O(2), changes in FiO(2) would be affected not by changes in FiCO(2), but by CO(2) production and gas movement around the infant's face. The rapid decrease of FiO(2) is approximated at the inverse of the FiCO(2) timecourse, suggesting the significance of not only CO(2) accumulation but also O(2) deprivation in the potential space around the baby's face.

Bedding and Linens↗

PubMed2006

Sudden infant death: lingual thyroglossal duct cyst versus environmental factors.

An 8-month-old female baby was found collapsed in the prone position 30 min after being positioned under soft-bedding. She was taken to the emergency room with cardiopulmonary arrest. Her heartbeat was recovered after resuscitation and continued for 20 h under artificial respiration, at which point the child died. At autopsy, the child showed no significant pathological abnormalities apart from a thyroglossal duct cyst of 2.0 cm diameter, therefore, it seemed that the cyst, which was close to the epiglottis, had caused asphyxia through airways occlusion. However, the child had shown no respiratory problems before death, and the risk of airway occlusion as a result of lingual cysts is more likely in a supine rather than a prone position. A small amount of evidence suggested that the child died as a result of suffocation from being covered by soft-bedding, which could have caused fatal asphyxia; it is also possible that a hypoxic state induced by airway obstruction might have been enhanced by being covered with bedding. It seemed reasonable to assume that death was caused by a combination of the lingual thyroglossal duct cysts and asphyxia caused by being covered in bedding, though the main factor appeared to be the large cyst.

Airway Obstruction↗

PubMed2005

12 Y-chromosomal STR haplotypes in Japanese.

Haplotypes and allele frequencies of 12 Y-STRs were examined in a population sample of 381 Japanese male volunteers. A total of 315 haplotypes were identified, of which 288 haplotypes were unique, and 18, three, three, two, one and one were found in two, three, four, five, eight and 18 individuals, respectively. Total gene diversity was 0.997.

Asian People↗

PubMed2005

Concentrations of toluene in the body killed by an injury to the head shortly after ingesting thinner.

An autopsy was conducted on a male showing leather-like skin damage, revealing the cause of death to be an injury to the head. Thinner was found scattered around the scene of death, and stomach and intestine contents smelled strongly of solvent. Toxicological analysis was conducted to determine whether or not the solvent was of a lethal level. Using gas chromatography, peaks of toluene, xylene, and ethylbenzene were detected in the blood and gastric contents. No toluene was detected in the urine, and therefore it was concluded that the decedent died of a severe head injury shortly after solvent ingestion. In the literature, toluene concentrations in blood and lung samples were determined as both fatal and non-fatal but clear differences in the fatality of toluene in solid organ samples, namely, the brain, liver and kidneys were shown. The brain is especially useful in postmortem analysis. In this case, the concentration of toluene in the brain was 20.0 microl/g, which was considered as a non-lethal level.

Benzene Derivatives↗

PubMed2005

18O-labeling quantitative proteomics using an ion trap mass spectrometer.

We describe a method for simultaneous identification and quantitation of proteins within complex mixtures. The method consists of 18O-labeling, a simple stable isotope-coding that requires merely enzymatic digestion in 18O-water, in combination with a capillary-liquid chromatography electrospray ion-trap mass spectrometer. In a separate experiment using the same sample and a spike test, we demonstrate that the difference ration was calculated accurately using the 18O-labeling method even if the protein was part of a complex mixture. Our data also suggest that the accuracy of the quantitation can be improved by averaging the difference ratios of several peptides. In comparing our method with the isotope-coded affinity tag (ICAT) method, we show that the 18O-labeling method has the advantages of better recovery and fewer isotope effects. Therefore, the 18O-labeling method is a powerful tool for large-scale proteomics applications.

Animals↗

PubMed2005

The relationship of a high level of serum beta-hydroxybutyrate to cause of death.

To examine the state of ketoacidosis in relation to the cause of death, three kinds of ketone bodies (acetoacetate, beta-hydroxybutyrate and acetone) were measured in postmortem serum. Of 100 autopsy cases, 22 had ketone body increasing pathophysiological conditions, overlapped in some cases, namely a poorly-nourished state (10 cases), alcoholic fatty liver damage (10), diabetes (5) and infectious disease (5). Of the 3, 11, 7 and 15 cases in which the beta-hydroxybutyrate concentration was greater than 10,000, 1000-10,000, 500-1000 and 200-500 micromol/l, 3 (100%), 8 (73%), 3 (43%) and 5 (33%), respectively, had one or more pathophysiological conditions that usually produce ketone bodies. Of the 64 cases in which the beta-hydroxybutyrate concentrations were less than 200 micromol/l, only 3 (5%) had some of these conditions. Cases showing high levels of ketone bodies tended to have pathophysiological states that can produce them, although the level of beta-hydroxybutyrate and these states did not show parallel relationships. When autopsy findings fail to explain the cause of death, a diagnosis as death caused by ketoacidosis would be reasonable if the serum beta-hydroxybutyrate level is over 1000 micromol/l and the body has pathophysiological conditions that tend to increase ketone bodies.

3-Hydroxybutyric Acid↗

PubMed2005

Melatonin as a local regulator of human placental function.

Melatonin plays a critical role in a variety of mammalian reproductive processes not only acting on the central nervous system but also behaving as a peripheral physiologic regulator. To address the relevance of melatonin to the maintenance of pregnancy at the feto-maternal interface, we investigated the expression of two types of membrane melatonin receptors, MT1 and MT2, as well as arylalkylamine N-acetyltransferase (AA-NAT) and hydroxyindole-O-methyltransferase (HIOMT), the two enzymes required for the conversion of serotonin to melatonin, in the human placenta and the effect of melatonin on the release of human chorionic gonadotropin (hCG) from cultured human trophoblast cells. RT-PCR analysis and DNA sequencing revealed that transcripts of MT1, MT2, AA-NAT, and HIOMT were present in the first-trimester human placenta. We also found that melatonin significantly potentiated hCG secretion at optimal concentrations. These results suggest that melatonin may regulate human placental function in a paracrine/autocrine manner, providing evidence for a novel role in human reproduction.

Acetylserotonin O-Methyltransferase↗

PubMed2005

Purification and cDNA cloning of NADPH-dependent aldoketoreductase, involved in asymmetric reduction of methyl 4-bromo-3-oxobutyrate, from Penicillium citrinum IFO4631.

Penicillium citrinum was found to catalyze the reduction of methyl 4-bromo-3-oxobutyrate to methyl (S)-4-bromo-3-hydroxybutyrate [(S)-BHBM] with high optical purity. From the strain, a cDNA clone encoding a novel NADPH-dependent alkyl 4-halo-3-oxobutyrate reductase (KER) was isolated. Escherichia coli cells overexpressing KER produced (S)-BHBM in the presence of an NADPH-regeneration system.

Alcohol Oxidoreductases↗

PubMed2004

Identification of major proteins in the lipid droplet-enriched fraction isolated from the human hepatocyte cell line HuH7.

Recent studies have revealed the presence of intracellular lipid droplets in wide variety of species. In mammalian cells, there exist proteins specifically localize in lipid droplets. However, the protein profile in the droplet remains yet to be clarified. In this study, a fraction enriched with lipid droplets was isolated from a human hepatocyte cell line HuH7 using sucrose density gradient centrifugation, and 17 major proteins in the fraction were identified using nano LC-MS/MS techniques. Adipose differentiation-related protein (ADRP) was the most abundant protein in the fraction. The secondary abundant proteins were identified to be acyl-CoA synthetase 3 (ACS3) and 17beta-hydroxysteroid dehydrogenase 11 (17betaHSD11). Included in the identified proteins were five lipid-metabolizing enzymes as well as two lipid droplet-specific proteins. When HuH7 cell lysate was fractionated by a density gradient, most of 17betaHSD11 was found in the droplet-enriched fraction. In immunocytochemical analysis, 17betaHSD11 showed ring-shaped images which overlapped with those for ADRP. These results suggest that a specific set of proteins is enriched in the lipid droplet-enriched fraction and that 17betaHSD11 localizes specifically in the fraction.

17-Hydroxysteroid Dehydrogenases↗

PubMed2004

Mouse testis transcriptome revealed using serial analysis of gene expression.

We applied serial analysis of gene expression (SAGE) to the mouse testis to reveal the global gene expression profile and to identify senescence-dependent changes in that profile. A total of 61,929 SAGE tags, including 19,323 unique tags, were obtained from 3- and 29-month-old BDF1 mice and 14-month-old SAMP1 mice. Genes highly expressed in the testis included those associated with spermatogenesis, protein metabolism, energy metabolism, growth and differentiation, and signal transduction. Testes from old mice of both strains appeared atrophied. Morphological examination of aged testes revealed extremely thin seminiferous epithelia and significantly decreased numbers of spermatids and spermatocytes. Despite the physical deterioration, no gross changes in the gene expression profile were apparent in the testes of old BDF1 mice. However, in 14-month-old SAMP1 mice, protamine 2 gene transcription was approximately 50% lower than in BDF1 mice. This reduction may be associated with the oligozoospermia and early decline in reproductive performance of SAMP1 mice. Our SAGE results are the first quantitative gene expression profile of the mouse testis and provide a reliable transcriptome reference for this organ.

Age Factors↗

PubMed2003

Positive association between panic disorder and polymorphism of the serotonin 2A receptor gene.

Family and twin studies have shown that genetic factors play an important role in the etiology of panic disorder. However, linkage and association studies using DNA markers have yielded inconclusive results. Increased serotonin neurotransmission may cause or be related to panic disorder. Assuming that genes regulating the serotonin system are involved in the pathogenesis of panic disorder, the authors searched for a genetic association of panic disorder with the serotonin 1A (HTR1A), 2A (HTR2A), and 2C (HTR2C) receptor genes. HTR1A, HTR2A and HTR2C polymorphisms were detected by the polymerase chain reaction method with analysis of restriction fragment-length polymorphisms (PCR-RFLP). The subjects were 63 biologically unrelated patients with panic disorder and 100 biologically unrelated normal control subjects who were native Japanese living in the western area of Japan. HTR1A and HTR2C showed no significant association with panic disorder. However, the frequency of the MspI A2 allele of HTR2A was significantly higher in the patients than in the normal control subjects. The study showed a positive association between panic disorder and the HTR2A gene, suggesting that HTR2A plays an important role in the pathogenesis of panic disorder.

Adolescent↗

PubMed2003

Proteomic analysis of rat heart in ischemia and ischemia-reperfusion using fluorescence two-dimensional difference gel electrophoresis.

Ischemia-reperfusion injury is a major complication occurring in acute myocardial infarction, cardiopulmonary bypass surgery, and heart transplantation. The aim of this study was to identify proteins that were involved in ischemia-reperfusion injury using fluorescence two-dimensional difference gel electrophoresis. We compared the 100,000 x g precipitate fractions of normal, ischemic and ischemia-reperfused rat hearts and detected six spots which changed more than two-fold in expression level and two additional spots related to these spots. Using peptide mass fingerprinting by matrix-assisted laser desorption/ionization-time of flight mass spectrometry, we identified five of these spots as protein disulfide isomerase A3 (PDA3), one as 60 kDa heat shock protein (HSP60) and two as elongation factor Tu (EF-Tu). HSP60 was increased during ischemia and decreased to normal expression level after reperfusion. EF-Tu was increased in ischemia but not decreased by reperfusion. We also found that several protein spots of PDA3 shifted towards a higher isoelectric point in ischemia and ischemia-reperfusion. Our data strongly suggested that PDA3 underwent dephosphorylation during ischemia and reperfusion and serine 343 of PDA3 was one of the phosphorylation sites.

Animals↗

PubMed2002

The influence on the schizophrenic symptoms by the DRD2Ser/Cys311 and -141C Ins/Del polymorphisms.

The hyperactivity of dopaminergic systems is one of the major etiological hypotheses of schizophrenia. The major support for this hypothesis is that effective antipsychotic drugs bind to dopamine receptors and improve acute schizophrenic symptoms. For this reason, we investigated the allelic association between schizophrenia and polymorphisms of the DRD2 genes for the Ser/Cys311 and -141C Ins/Del. The subjects were 190 schizophrenics (120 males and 70 females) and 103 normal controls (53 males and 50 females). There were no significant differences between the patients and controls in the allele frequencies and the frequencies of the genotypes. We found no statistical association between schizophrenia and polymorphisms of the DRD2 genes for the Ser/Cys311 and -141C Ins/Del. These results indicate that the DRD2 gene may not develop schizophrenia. Next, we examined whether the genotypes influence the symptoms of schizophrenia the using Positive and Negative Symptom Scale scores. The Ser/Cys patients exhibited significantly lower positive and negative symptom scores than Ser/Ser patients. Patients with Del/Del, Ins/Del, or Ins/Ins showed higher positive symptom scores in descending order. This result suggested that the Del allele worsens the positive symptoms. We concluded that the DRD2 receptor gene may not influence the onset of schizophrenia, but there is a strong possibility that the Cys311 and -141C Del have a significant influence on the symptoms of schizophrenia.

Adult↗