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Biomedical subjects

K Okamura

Publications and source records attributed to K Okamura.

At least 649 records · Page 36Linked to original sources
PubMedDate not supplied

Postnatal exposure to chlorinated dioxins and related chemicals on lymphocyte subsets in Japanese breast-fed infants.

Effects of postnatal exposure to polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and coplanar polychlorinated biphenyls (Co-PCBs) on lymphocyte subpopulations were investigated in the peripheral blood of 36 breast-fed Japanese babies. As a result, estimated total intakes of these chemicals in toxic equivalent quantity (TEQ) converted into 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) equivalents from the breast milk positively and negatively correlated with the respective percentages of CD4+ and CD8+ lymphocytes in the blood of breast-fed babies. Consequently, the ratios of CD4+ to CD8+ T cells showed significant increasing tendency with the estimated total TEQ intakes. Therefore, our study suggests that exposure to background levels of the highly toxic organochlorine compounds through the breast milk influences the human neonatal immune system.

Adult↗
PubMedDate not supplied

Postnatal exposure to chlorinated dioxins and related chemicals on thyroid hormone status in Japanese breast-fed infants.

Effects of postnatal exposure to polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and coplanar polychlorinated biphenyls (Co-PCBs) on thyroid hormone status were studied in the peripheral blood of 36 breast-fed Japanese infants. Estimated total intakes of these chemicals in toxic equivalent quantity (TEQ) converted into 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) from the breast milk significantly and negatively correlated with the levels of triiodothyronine (T3) and thyroxine (T4) in the blood of breast-fed babies. Therefore, exposure to background levels of the highly toxic organochlorine chemicals through the breast milk may cause some effects on thyroid hormone status in Japanese infants.

Adult↗
PubMedDate not supplied

Characterization of solubilized microvillous membrane proteins and glycoproteins from human placental syncytiotrophoblast.

Microvillous membrane fractions from human term placentae were prepared by differential centrifugation. Extration of membranes with PBS-EDTA or KCI removed soluble cytoplasmic components and serum proteins excepting trace amounts of albumin and transferrin. PAGE-SDS revealed 11 components in the Triton solubilized crude fraction after PBS-EDTA extraction. Membrane components solubilized with Triton were not fractionated by gel filtration on Bio-Gel A-50 m but DEAE-cellulose chromatography partially resolved these components. Three fractions were obtained by stepwise elution of absorbed materials using increasing concentrations of NaCl in the equilibrating buffer. These fractions were characterized using SDS-PAGE. The material unabsorbed to the DEAE contained two components of small molecular weight and one of them showed a positive PAS stain. The first eluted protein peak showed nine components, seven of which stained with PAS. The bulk of glycoproteins with molecular weights greater than 130 000 daltons were found in this fraction. The second eluted peak from DEAE was rich in components with molecular weights less than 42 000 daltons. Four components in this fraction were not identified in the other two ion-exchange fractions. Bands representing mobilities of albumin, transferrin and alkaline phosphatase were observed in DEAE-cellulose fractions; however, 12 components of unknown structure were revealed.

Albumins↗
PubMedDate not supplied

Mechanical strength of latissimus dorsi tendon transfer with Teflon felt augmentation.

Tensile properties of Teflon felt augmentation after latissimus dorsi tendon transfer to rotator cuff defect were examined in dog cadaver shoulders. Two experimental groups with latissimus dorsi tendon transfer were designed. In group 1 (right shoulders, n = 7) the tendon ends of latissimus dorsi were sutured to the greater tuberosity. In group 2 (left shoulders, n = 7) the repair was augmented with Teflon felt at the suture site. The ultimate tensile force and stiffness of each specimen in group 2 were individually compared with those in group 1. The average increases in ultimate tensile force and stiffness in group 2 were 53.8% and -3.7%, respectively. The individual value of ultimate tensile force in group 2 was significantly greater than that in group 1. These results demonstrate that augmentation at the repair site is mechanically effective latissimus dorsi tendon transfer. The augmentation procedure may provide protection during the healing period because of this and a surrounding fibrous tissue reaction.

Animals↗
PubMedDate not supplied

Scopadulciol, an inhibitor of gastric H+, K(+)-ATPase from Scoparia dulcis, and its structure-activity relationships.

A new tetracyclic diterpenoid, scopadulciol [3], together with 6-methoxybenzoxazolinone, glutinol, and acacetin, was isolated from the 70% EtOH extract of Scoparia dulcis collected in Taiwan. Its structure was elucidated to be 6 beta-benzoyl-12-methyl-13-oxo-9(12)a,9(12)b-dihomo-18-podocarpanol on the basis of spectral data. It mildly inhibited hog gastric H+, K(+)-ATPase. Examination of the inhibitory activities of derivatives of scopadulcic acid B [2], including 3, revealed that methylation of the carboxyl group and introduction of an acetyl group or oxime at C-13 or C-18 markedly enhanced the inhibitory activity, while debenzoylation reduced the activity. Among the 30 compounds tested, compound 12, a methyl ester of scopadulcic acid B [2], showed the most potent activity.

Abietanes↗
PubMedDate not supplied

Expression of organic anion transporting polypeptide E (OATP-E) in human placenta.

PURPOSE: To examine the expression of multifunctional Na(+)-independent organic anion transporting polypeptide, termed OATP-E, involved in the transport of thyroid hormone in human placenta. METHODS: Western blot analysis was performed using a specific antibody against OATP-E in human placenta to confirm the expression of OATP-E at the protein level. Immunohistochemistry was also performed using the specific antibody against OATP-E on frozen sections of human placenta. RESULTS: By Western blot analysis, a single band for OATP-E was observed in human placenta. Immunohistochemistry revealed that OATP-E was predominantly expressed at the apical surface of the syncytiotrophoblasts in placenta. CONCLUSION: These results reveal that OATP-E is expressed in human placenta, suggesting a functional role for the transplacental transfer of thyroid hormone.

Adult↗
PubMedDate not supplied

Intracytoplasmic sperm injection: stiletto conception or a stab in the dark.

To describe the importance of molecular and cellular analyses in intracytoplasmic sperm injection (ICSI) the authors review the literature on biological challenges in ICSI and associated techniques. Several matters can be proposed in molecular and cellular challenges in ICSI for safety and efficacy: (1) a reliable and convenient animal model for understanding the molecular and cellular basis of human ICSI must be established, and molecular and cellular analysis of the first cell cycle of human fertilization should be better understood; (2) a proper assay for human sperm function that contributes to the indication for ICSI should be developed; and (3) de novo and transmitted genetic security in ICSI should be examined.

Animals↗
PubMedDate not supplied

Provider characteristics: impact on bone density utilization at a health maintenance organization.

OBJECTIVE: Information from bone mineral density (BMD) is relevant in guiding postmenopausal osteoporosis prevention and treatment, yet many providers do not typically order BMDs. This study was designed to identify physician characteristics associated with utilization of bone densitometry in a northeastern US health maintenance organization (HMO). DESIGN: Internal medicine primary providers in practice at a northeastern HMO between April 1997 and March 1998 were categorized by BMD utilization, based on the number of BMDs performed during that time per number of women older than 50 years in their patient panel. In one analysis, providers in the highest quintile for this parameter were considered "high utilizers" (n = 25), and those in the lowest quintile, "low utilizers." These groups were compared with respect to provider characteristics and practice composition. In a second analysis, multiple variable linear regression was used to predict the likelihood of utilization of BMD as a function of those parameters for all providers. RESULTS: The range of BMDs by provider was 0 to 190 per 1,000 women >50 years (median = 34) over this 1-year period. Providers who were high utilizers had a significantly greater number of female patients more than age 50 in their practice (p < 0.05) and were also more likely themselves to be female (62% vs. 48%; p < 0.05). There was no association between BMD utilization and age of provider or years in practice. Female provider gender (p < 0.01) and greater percentage of women more than age 50 in the practice (p < 0.05) were independent predictors of BMD utilization in a multivariate model. CONCLUSION: BMDs were infrequently utilized by the majority of providers over this 1-year period. Female provider gender was associated with a significantly greater likelihood of BMD utilization that was not simply explained by the greater number of women in these providers' practices. These findings may be relevant to identifying strategies to improve bone health care in this population.

Absorptiometry, Photon↗
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Primary ependymoma of the ovary: a case report and literature review.

Ependymoma is a glioma with differentiation toward ependymal cells that usually arises in the central nervous system. Ovarian ependymoma is extremely rare, and the treatment strategies for this disease have not been established. This is the first report of a patient with advanced ovarian ependymoma who received fertility-sparing surgery and is now alive without disease. A 23-year-old Japanese woman, gravida 0, presented with a chief complaint of lower abdominal distension and weight loss. She underwent left salpingo-oophorectomy for suspected ovarian cancer. Microscopic examination revealed a highly cellular tumor composed of small cells with hyperchromatic, round-to-oval nuclei and scanty cytoplasm. Perivascular pseudorosettes, ependymal rosettes, and extensive necrosis were observed. After thorough pathologic examination, she was diagnosed as having stage IIIC ovarian ependymoma. Postoperatively, she received adjuvant chemotherapy and underwent secondary cytoreductive surgery that preserved the uterus and right ovary. Her menstrual cycle has resumed, and she is alive without evidence of disease 16 months after the start of treatment. Although rare, primary ovarian ependymoma must be kept in mind in the differential diagnosis of ovarian tumors, especially in young women. Administration of etoposide-based chemotherapy along with cytoreductive surgery is a potential standard treatment for advanced ovarian ependymoma.

Adult↗
PubMedDate not supplied

Alteration in the low-frequency domain in power spectral analysis of fetal heart beat fluctuations.

OBJECTIVE: Spectral analysis was conducted on fetal heart rate fluctuations for the purpose of investigating the change in gestational age and examining the usefulness as a method of estimating fetal blood gas. STUDY DESIGN: Five hundred and twenty-nine pregnant women with a single normal fetus and 26 women with intrauterine growth restriction (IUGR) were studied during the 20th to 38th gestational weeks. In cases of IUGR, fetal blood gas levels were evaluated with percutaneous umbilical blood sampling. A time series of fetal heart rate fluctuation was obtained with a 1. 15-MHz ultrasonic transducer, and power spectral analysis of 200 consecutive stable beats was performed with an autoregression method. Integrated areas of 0.025-0.125 cycles/beat were defined as low-frequency areas (LFAs) and were examined in normal fetuses. In addition, the relation between LFA and fetal blood gas values was studied. RESULTS: As pregnancy progressed, LFA increased with a cubic regression equation (Y = 6.484 - 0.764X + 0.029X2 - 0.00034X3). The correlation coefficient was 0.625 (p < 0.05). In the cases of IUGR, DeltaLFA was highly correlated with DeltapO2 and DeltapH (correlation coefficient, 0.650 and 0.618, respectively). CONCLUSIONS: Measurement of LFA provides insight into the development of fetal autonomic function and also may serve as a quantitative index of fetal well-being in mid-pregnancy.

Adolescent↗
PubMedDate not supplied

Prenatal diagnosis of lissencephaly by magnetic resonance image.

Two cases of lissencephaly were prenatally diagnosed by a magnetic resonance image (MRI). Smooth surface of brain and remarkable sylvian fissure, which were barely detectable by ultrasound, were easily observed in MRI. MRI is the most appropriate tool in diagnosing lissencephaly.

Adult↗
PubMedDate not supplied

Diagnostic use of cordocentesis in twin pregnancy.

We performed percutaneous umbilical blood sampling, under ultrasound guidance, in both twins of 11 twin pregnancies in whom twin-to-twin transfusion syndrome was suspected. Chorionicity and the presence of placental vascular anastomoses were assessed postnatally. The hemoglobin concentration, hematocrit and other biochemical variables in fetal blood were evaluated in both twins. The mean hemoglobin difference between the large and small twins was 4.8 g/dl (range 1.8-8.1 g/dl) in 5 monochorionic discordant twin pairs, and 1.2 g/dl in a monochorionic twin pair without discordancy. Hemoglobin values did not differ between dichorionic twins. The mean hematocrit difference between monochorionic discordant twins was 18.3%. In dichorionic discordant twins, the inter-twin hematocrit difference was very small. Total protein and albumin were normal in all twins.

Cordocentesis↗
PubMedDate not supplied

Diagnostic fetal blood sampling-technique related losses.

BACKGROUND: The applications of cordocentesis are limited by its safety. Cordocentesis is performed either freehand or with the aid of a fixed needle guide. Recent reports suggest a loss rate of 1-7% using the freehand technique. The potential influence of technique on the perinatal loss rate has not been examined. STUDY DESIGN: The procedure-related loss rates of two fetal diagnosis and treatment units, one in the United States (10 operators) and one in Japan (15 operators), who perform diagnostic cordocentesis with the aid of a fixed needle guide is calculated from a prospectively maintained database and compared to the published experience of large centers who use a freehand technique. RESULTS: A total of 1,260 diagnostic cordocenteses were performed. The mean gestation at sampling was 29.1 +/- 5 weeks. The umbilical vein was punctured in 90%. There were 12 procedure-related losses yielding an overall perinatal loss rate of 0.9%. There was no relationship between the risk of a loss and the number of prior procedures the operator had performed. Losses were more often associated with puncture of the umbilical artery (41.7 vs. 9.2%, p = 0.002). Eleven of 12 losses were associated with a postprocedure bradycardia. Eight fetuses who died had either a trisomy or triploidy, 1 had renal agenesis, 2 had severe early-onset growth restriction and 1 had rhesus disease. For all diagnoses other than a chromosome abnormality and severe fetal growth restriction, the procedure-related loss rate from diagnostic cordocentesis was 0.2% (2/1,021). CONCLUSION: This study suggests that technique is a variable in the loss rate for cordocentesis.

Bradycardia↗
PubMedDate not supplied

Effect of administered human growth hormone on protein metabolism in septic rats.

The effect of administered human growth hormone (hGH) on protein metabolism in septic rats was investigated. Fifty-three male Wistar rates with SVC cannulation were divided into four groups. Group I (n = 10) underwent sham-operation. Sepsis was induced by cecal ligation in group II (n = 19), group III (n = 10), and group IV (n = 14). Isocaloric, isonitrogenous glucose/amino acids were infused for 4 days. hGH was administered in group III (100 mU/day) and group IV (200 mU/day) every day. Cumulative nitrogen balance (mg/kg) in group IV was significantly higher than in group II (p less than 0.01): group I, 1264 +/- 355; group II, 117 +/- 693; group III, 92 +/- 735; group IV, 1001 +/- 279. Cumulative urinary excretion of 3-methylhistidine (3-MH, mg/kg) did not differ between group II and group IV: group I, 6.2 +/- 0.9; group II, 12.0 +/- 2.2; group III, 13.4 +/- 2.9; group IV, 10.5 +/- 2.3. Serum albumin level in group IV (1.8 +/- 0.2 g/dl) was significantly higher than in group II (1.5 +/- 0.2 g/dl) (p less than 0.01). Blood urea nitrogen level in group IV (12.6 +/- 2.3 mg/dl) was significantly lower than in group II (18.8 +/- 7.4 mg/dl) (p less than 0.05). Although serum levels of glucose, insulin, triglyceride, and phospholipid were higher in sepsis groups than in sham-operated group, those levels did not differ among sepsis groups. Administration of hGH, 200 mU/day, resulted in marked nitrogen retention and had little effect on 3-MH excretion.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMedDate not supplied

Glutamine-supplemented parenteral nutrition improves gut mucosa integrity and function in endotoxemic rats.

The effects of glutamine-supplemented parenteral nutrition on protein metabolism, small intestinal mucosal metabolism, morphology, and barrier function were studied in endotoxin-treated rats. Forty-six male Wistar rats were randomized to two groups of 23 animals each and received total parenteral nutrition solutions supplemented with either glutamine (GLN group) or glycine (GLY group) at 2% wt/vol. Endotoxemia was induced by continuous intravenous infusion of endotoxin at a dose of 2 mg/kg per day throughout the 4-day study period. The GLN group had a less-negative cumulative nitrogen balance (-14.0 +/- 132.8 mg of nitrogen in the GLN group and -86.8 +/- 161.7 mg of nitrogen in the GLY group, p < .05) and less cumulative excretion of urinary 3-methylhistidine (2910 +/- 593 nmol) than the GLY group (4447 +/- 933 nmol, p < .01). Jejunal mucosal glutaminase activity and the arterio-portal venous blood glutamine concentration differences were significantly higher in the GLN group compared with the GLY group (15.6 +/- 2.3 vs 11.1 +/- 1.9 mumol/g per minute, p < .05, and 181 +/- 52 vs 147 +/- 36 nmol/mL, p < .05, respectively). The morphology of the jejunal mucosa in the GLN group was significant for having greater mucosal weight (23.4 +/- 3.1 vs 17.6 +/- 2.5 mg/cm), villus height (445 +/- 75 vs 357 +/- 57 microns), crypt depth (197 +/- 34 vs 161 +/- 28 microns), and wall thickness (751 +/- 77 vs 648 +/- 102 microns) than the GLY group (p < .05).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMedDate not supplied

Insulin-like growth factor-I prevents gut atrophy and maintains intestinal integrity in septic rats.

BACKGROUND: The effects of insulin-like growth factor-I (IGF-I) on gut metabolism, structure, and barrier function as well as its general anabolic effects were investigated in septic rats. METHODS: Thirty-three male Wistar rats that underwent cecal ligation were randomly divided into one of the following two groups: (1) received only total parenteral nutrition (control group) or (2) received total parenteral nutrition with IGF-I (IGF group) at a dose of 4 mg/kg/d for 3 days. RESULTS: During the 3-day period, the body weight of rats in the IGF group increased significantly over that of rats in the control group (17.1 +/- 2.6 vs 5.8 +/- 4.6 g, p < .01). The total and free IGF-I plasma concentrations were significantly higher in the IGF group than in the control group. The cumulative nitrogen balance was significantly more positive for the IGF group (423.9 +/- 24.3 mg of nitrogen) than for the control group (290.8 +/- 26.0 mg of nitrogen). The weights of thymus, spleen, and kidneys were significantly increased in the IGF group compared with weights in the control group. Treatment with IGF-I improved the gut mucosal weight in all regions of the gut examined, including duodenum, jejunum, ileum, and colon. Histologic and biochemical analyses of the jejunum showed greater villus height and crypt depth and higher mucosal DNA and protein content in the IGF group. The arterial concentration of endotoxin was not significantly different between the two groups, whereas its level in portal blood was significantly lower in the IGF group (23.2 +/- 9.9 pg/mL) than in the control group (95.5 +/- 37.9 pg/mL), an indication that IGF-I treatment decreased the amount of endotoxin that traversed the gut barrier. CONCLUSIONS: These results indicate that IGF-I can improve gut metabolism and reduce mucosal atrophy and that it may play a role in maintaining the gut barrier function in sepsis.

Amino Acids↗
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Greater tuberosity notch: an important indicator of articular-side partial rotator cuff tears in the shoulders of throwing athletes.

We examined the location of rotator cuff tears, associated labral injuries, and notches on the greater tuberosity of the humeral head in shoulders of throwing athletes. Arthroscopic findings (rotator cuff tear, labral condition, and greater tuberosity notch) as well as other factors (duration of playing baseball, range of motion, and joint laxity) of 61 baseball players were retrospectively studied. The presence of a greater tuberosity notch was also evaluated for by plain radiographs. Forty patients had articular-side partial rotator cuff tears, most of which occurred in the interval between the supraspinatus and infraspinatus tendons. The existence of a rotator cuff tear was not related to the range of motion, joint laxity, the detachment of the superior glenoid labrum, or posterosuperior labral injury. Greater tuberosity notches were recognized in 38 shoulders by arthroscopy and most were detected on plain radiographs. The presence of a notch was significantly related to the existence of a rotator cuff tear, while the size of the notch was significantly related to the depth and width of the tear. The greater tuberosity notch seems to be one of the most important diagnostic indicators for a rotator cuff tear in throwing athletes.

Adolescent↗