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Biomedical subjects

A Morikawa

Publications and source records attributed to A Morikawa.

At least 73 records · Page 4Linked to original sources
PubMed2000

Biliary excretion of 17beta-estradiol 17beta-D-glucuronide is predominantly mediated by cMOAT/MRP2.

PURPOSE: The mechanism for the biliary excretion of 17beta-estradiol 17beta-D-glucuronide (E(2)17betaG), a cholestatic metabolite of estradiol, is still controversial. The purpose of the present study is to examine the transport of E(2)17betaG across the bile canalicular membrane. METHODS: We examined the uptake of [3H]E(2)17betaG by isolated canalicular membrane vesicles (CMVs) prepared from Sprague-Dawley (SD) rats and Eisai Hyperbilirubinemic rats (EHBR) whose canalicular multispecific organic anion transporter/multidrug resistance associated protein 2 (cMOAT/MRP2) function is hereditarily defective. Also, in vivo biliary excretion of intravenously administered [3H]E(2)17betaG was examined. RESULTS: In CMVs prepared from SD rats, but not from EHBR, a marked ATP-dependent uptake of [3H]E(2)17betaG was observed. Moreover, E(2)17betaG competitively inhibited the ATP-dependent uptake of [3H]2,4-dinitrophenyl-S-glutathione (DNP-SG). In addition, no significant inhibitory effect of verapamil (100 microM) and PSC-833 (5 microM) on the uptake of [3H]E(2)17betaG was observed. In vivo, the biliary excretion of intravenously administered [3H]E(2)17betaG was severely impaired in EHBR while the biliary excretion of [3H]E(2)17betaG in SD rats was reduced by administering a cholestatic dose (10 micromol/kg) unlabeled E(2)17betaG, but not by PSC-833 (3 mg/kg). CONCLUSIONS: The transport of E(2)17betaG across the bile canalicular membrane is predominantly mediated by cMOAT/MRP2.

Animals↗
PubMed2000

Effects of bathing immediately after birth on early neonatal adaptation and morbidity: a prospective randomized comparative study.

OBJECTIVE: Because the risks and benefits of early bathing of newborn infants are not well established, we investigated the effects of bathing immediately after birth on rectal temperature, respiratory rate, heart rate, blood pressure, percutaneous arterial blood oxygen saturation (SpO2) and early neonatal morbidity. METHODS: The study was designed as a randomized prospective comparative study in the neonatal care unit of a university hospital. A total of 187 healthy term and near-term newborn infants, who were delivered vaginally without asphyxia, between January and December 1997 were the study subjects. We compared findings in newborns who were bathed 2-5 min after birth (n = 95) with those of a control group (n = 92) who received dry care instead. Groups were comparable with respect to gestational age, birthweight, male: female ratio, Apgar score and umbilical blood pH. Rectal temperature was measured with an electronic thermometer immediately before the intervention bathing or dry care and at 30 min and 1, 2, 3, 8 and 12 h after birth. Heart rate, respiratory rate, systolic and diastolic blood pressure and SpO2 were measured at 1, 2, 8 and 12 h after birth. The incidence of early neonatal morbidity, including hyperbilirubinemia and gastrointestinal and respiratory problems, was also compared. RESULTS: Rectal temperature changed over time postnatally in both groups (P < 0.0001, ANOVA) and there was a significant difference in rectal temperature between groups (P< 0.0001, ANOVA). Mean (+/- SEM) rectal temperature at 30 min after birth (i.e. approximately within 20 min after intervention) was significantly higher in the bathed group than in the control (dry care) group (37.30 +/- 0.06 is 37.00 +/- 0.05 degrees C, respectively; P = 0.000022). Respiratory rate, heart rate, blood pressure and the ratio of the number of infants with SpO2 90-94% and 95-100% did not differ significantly between the two groups. The incidence of early neonatal morbidity, including vomiting, acute gastric mucosal lesion, polycythemia, need for tube feeding, phototherapy and oxygen therapy, also did not differ between the two groups. CONCLUSIONS: Early bathing, minutes after birth, did not appear to adversely affect the adaptation of healthy full-term and near-term newborn infants.

Age Factors↗
PubMed2000

Ultrasonographic detection of very thin percutaneous central venous catheter in neonates.

To assess the ability of ultrasonography to detect the tip of a very thin (0.4 mm outer diameter) percutaneous central venous catheter (PCVC) in neonates, the PCVC tip location was assessed by ultrasonography (US) and compared to the location estimated by standard radiography for 57 PCVCs in 44 neonates. Of 57 occasions, the examiner could not find the PCVC tip in three cases (5%). In the remaining 54 instances, in 87% of cases, the PCVC tip position was consistent with the location implied by skeletal landmarks on standard radiographs. On 24 occasions we also assessed catheter tip dislodgement according to flexion and extension of the infant's arm. US could detect 78% of cases of catheter tip dislodgement. The PCVC tip was sometimes visualized as a dot and parallel lines as well as mere parallel lines. In a large population of cases, US is a reliable method for detection of a thin PCVC tip. US provides precise information about the PCVC tip position in relation to vascular structure and contributes to safer positioning of the PCVC than traditional radiography alone.

Age Factors↗
PubMed2000

Morphological change in Pseudomonas aeruginosa following antibiotic treatment of experimental infection in mice and its relation to susceptibility to phagocytosis and to release of endotoxin.

The relationship between morphological changes in Pseudomonas aeruginosa following antibiotic treatment of experimental infection in mice, susceptibility to phagocytosis, and release of endotoxin was studied. The intraperitoneal administration of P. aeruginosa with imipenem or ceftazidime into mice induced morphological changes in the cells 2 h after injection. Round P. aeruginosa cells with imipenem treatment became susceptible to phagocytosis by peritoneal cells, whereas long filamentous cells with ceftazidime treatment were hardly phagocytized by peritoneal cells. The morphological changes also affected the plasma endotoxin level in the circulation.

Animals↗
PubMed2000

Augmentation of nitric oxide production by gamma interferon in a mouse vascular endothelial cell line and its modulation by tumor necrosis factor alpha and lipopolysaccharide.

The effect of gamma interferon (IFN-gamma), tumor necrosis factor alpha (TNF-alpha), and lipopolysaccharide (LPS) on nitric oxide (NO) production in the mouse vascular aortic endothelial cell line END-D was examined. LPS, TNF-alpha, and a low concentration of IFN-gamma inhibited NO production in END-D cells, while a high concentration of IFN-gamma definitely enhanced it. The NO production induced by a high concentration of IFN-gamma was further augmented by using IFN-gamma in combination with LPS or TNF-alpha. In sequential incubations of LPS and IFN-gamma, the enhancement of NO production required prior treatment with IFN-gamma. Stimulation of END-D cells with a high concentration of IFN-gamma led to the expression of inducible NO synthase (iNOS). The augmentation of NO production by IFN-gamma alone or in combination with LPS or TNF-alpha was completely blocked by several inhibitors of iNOS. It was strongly suggested that a high concentration of IFN-gamma itself enhanced NO production in END-D cells through inducing the expression of iNOS. LPS and TNF-alpha exclusively modulated the activity of iNOS once its expression was triggered by IFN-gamma. On the other hand, a low concentration of IFN-gamma, LPS, and TNF-alpha reduced NO production through down-regulating constitutive NOS (cNOS). The differential regulation of cNOS- and iNOS-mediated NO production by IFN-gamma, TNF-alpha, and LPS is discussed.

Animals↗
PubMed2000

Role of secretory IgA, secretory component, and eosinophils in mucosal inflammation.

Eosinophils and their products are important in the pathophysiology of allergic inflammation in mucosal tissues. Secretory component (SC) bound to IgA mediates transepithelial transport of IgA. As another biological activity of SC, we have reported that secretory IgA (sIgA) and SC preferentially activate human eosinophils. When eosinophils were stimulated with immobilized sIgA, degranulation and superoxide production were greater than when stimulated with serum IgA. In contrast, neutrophils responded similarly to sIgA and serum IgA. Superoxide production by eosinophils stimulated with cytokines was enhanced synergistically by immobilized SC, while SC showed no effect on neutrophil activation. Eosinophil superoxide production stimulated with sIgA was abolished by anti-CD18 mAb, suggesting that beta2 integrins might be crucial for this reaction. There are several reports that SC and sIgA may play important roles in regulating eosinophil functions in vivo in diseases associated with mucosal eosinophilia and in various allergic diseases. It is speculated that eosinophils in the mucosa are activated by SC or sIgA, and that subsequent degranulation and superoxide production are induced.

Animals↗
PubMed2000

Stimulation of the beta(2) integrin, alpha(M)beta(2), triggers tyrosine phosphorylation and cellular degranulation on human eosinophils.

Activation of human eosinophils by specific extracellular stimuli triggers the cellular degranulation response. Because cellular adhesion is critical for this eosinophil degranulation, we have tested the hypothesis that ligation of the beta(2) integrin, alpha(M)beta(2) (Mac-1, CD11b/CD18), leads to intracellular signaling events that contribute to the eosinophil activation response. Recently, we found that engagement of beta(2) integrin using two different approaches, such as cell adhesion induced by IL-5 or direct ligation of alpha(M)beta(2), triggered tyrosine phosphorylation of Cbl, the product of the c-cbl proto-oncogene, paxillin, a cytoskeletal protein, an unidentified 115-kD protein, and subsequent cellular degranulation. The results of this study indicate that engagement of alpha(M)beta(2) on eosinophils triggers an intracellular signaling cascade leading to cellular degranulation. Tyrosine phosphorylation of Cbl, paxillin, and a 115-kD protein may play important roles in adhesion-dependent cellular functions of eosinophils.

CD18 Antigens↗
PubMed2000

Bronchial hyperresponsiveness before and after the diagnosis of bronchial asthma in children.

OBJECTIVE: To assess at what age bronchial hyperresponsiveness (BHR) is acquired in children with asthma. BACKGROUND: A relationship between BHR and infantile wheezing diseases has been reported. Infants with a genetic predisposition to atopy are more likely to wheeze with respiratory viral infection or bronchiolitis, and it is suspected that the continued BHR after the first attack of asthma may be induced or triggered by some viral infections. Also, recent studies have reported the existence of atopic and BHR-related genes. However, whether BHR is congenital or acquired after asthma attacks, and when BHR in children with asthma is established or acquired remain unclear. METHODS: We performed methacholine inhalation challenge using a transcutaneous oxygen pressure (tcPO(2)) monitoring system in 205 children without asthma from 6 months to 6 years of age. During follow-up, 18 of these participants were diagnosed with asthma (group N-A). This group and 15 age-matched children without asthma (group N-N) were tested twice using methacholine inhalation challenge. For comparison, 39 age-matched atopic-type asthmatic children (group A-A) were also given the inhalation challenge twice. Methacholine inhalation challenge using a tcPO(2) monitoring system was performed while the participants were asleep in the supine position. Sequential doses of inhaled methacholine delivered by oxygen mask were doubled until a 10% decrease in tcPO(2) from the baseline was reached. The cumulative dose of methacholine at the inflection point of tcPO(2) (minimal dose of methacholine [Dmin]-PO(2)) was considered to represent BHR. RESULTS: In groups N-N and A-A, there was no difference in Dmin-PO(2) between the first and second challenge. However, the Dmin-PO(2) in group N-A significantly decreased from the first challenge to the second challenge. There was no significant difference between the Dmin-PO(2) in group N-N and the first Dmin-PO(2) in group N-A; or between the Dmin-PO(2) in group A-A and the second Dmin-PO(2) in group N-A. CONCLUSIONS: These data suggest that BHR in many infants with asthma is acquired after several asthma attacks.bronchial hyperresponsiveness, childhood asthma, methacholine inhalation challenge, transcutaneous oxygen pressure.

Asthma↗
PubMed2000

Endovascular treatment for a ruptured persistent trigeminal artery variant aneurysm on the distal portion--case report.

A 71-year-old female presented with a rare case of ruptured aneurysm on the distal persistent trigeminal artery (PTA) variant trunk. The endovascular approach was used to successfully occlude the proximal PTA variant, as direct catheter approach to the PTA variant aneurysm on the distal portion was prevented by the tortuous course of the vessel. She was discharged without neurological deficit.

Aged↗
PubMed2000

[Serum amyloid A levels in patients with hemophagocytic syndrome].

Concentrations of serum amyloid A protein (SAA) were measured in patients with hemophagocytic syndrome (HPS). There was a significant correlation between SAA and ferritin (p = 0.0003), while there was no significant correlation between C-reactive protein (CRP) and ferritin. These results indicate that SAA could be a useful clinical marker for activity of HPS.

Adolescent↗
PubMed2000

[Food allergy].

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Allergens↗
PubMed1999

Olfactory bulb dysplasia: a novel subtype of neuronal migration disorder.

We present a novel subtype of neuronal migration disorder found in a case of Pena-Shokeir phenotype, in which the deformation sequence originated from neurogenic fetal akinesia. The autopsied brain showed dysplastic features of dentate and olivary nuclei as well as a bilaterally enlarged olfactory bulb with abnormal laminar structures. The laminar structures comprised four layers: (1) a superficial layer without glomeruli, (2) a neuronal cell layer containing neurons simulating mitral cells, (3) a sparse cell layer enriched with tangential neuronal fibers, and (4) a reticular layer showing a mottled appearance with the accumulation of fine reticular neurites intermingled with granule cells. To our knowledge, these malformed laminar changes have never been reported, and we propose the term olfactory bulb dysplasia.

Autopsy↗
PubMed1999

Intestinal blood-flow velocity in uncomplicated preterm infants during the early neonatal period.

BACKGROUND: Intestinal blood-flow changes after birth. Objective. To elucidate the factors influencing intestinal blood-flow velocity in preterm infants during the early neonatal period. MATERIALS AND METHODS: We measured blood-flow velocity in the superior mesenteric artery by pulsed Doppler US in 44 uncomplicated infants with a gestational age of less than 34 weeks and from 1 to 6 days of age. RESULTS: Time-averaged mean blood-flow velocity significantly increased with age from 1 to 6 days old. There was a significant correlation of time-averaged mean blood-flow velocity with birth weight at 1, 2, 4, 5 and 6 days of age and with the amount of enteral feeding from 4 to 6 days of age. Multivariate analysis showed that partial correlation of time-averaged mean blood-flow velocity with birth weight at 2 days of age and that with the amount of enteral feeding at 5 days of age were significant. End-diastolic blood-flow velocity was significantly lower at 1 day of age in infants with patent ductus arteriosus than those without it. CONCLUSIONS: Age, birth weight, the amount of enteral feeding and patent ductus arteriosus are included in the determinants of intestinal blood-flow velocity in preterm infants.

Aging↗
PubMed1999

Transtubular potassium concentration gradient in preterm neonates.

To determine the postnatal changes in mineralocorticoid action on the cortical distal nephron in preterm neonates, we evaluated the transtubular potassium gradient (TTKG) and its relationship to other renal and non-renal parameters in 16 preterm neonates during the first 5 weeks of life. Preterm neonates were divided into two groups according to their gestational age: the first group (group A, n=9) had a gestational age less than 30 weeks and the second group (group B, n=7) had a gestational age over 30 weeks. TTKG in both groups increased significantly with postnatal age, and TTKG in group A was significantly lower than that in group B (P=0.0003; two-way repeated analysis of variance). TTKG in group A was significantly lower during the 2 weeks of postnatal life than that in full-term neonates [TTKG during 1st week (mean+/-SD) 3.73+/-1.32, P<0.00001; during 2nd week 7.77+/-3.60, P=0.0096 versus full-term neonates (n=19); 11.56+/-3.23]. TTKG in group B was significantly lower only during the 1st week of life (6.55+/-2.71, P=0.0013) compared with full-term neonates. Plasma aldosterone concentration did not correlate with TTKG value. Stepwise regression analysis showed that postnatal age, cortical lumen sodium concentration (CLNa), and clinical condition requiring the use of mechanical ventilation were independent variables that correlated significantly with TTKG. We postulate that the low TTKG level in preterm neonates might reflect the prematurity of renal function (early postnatal age, CLNa) and the condition(s), relating to immaturity, such as the use of mechanical ventilation.

Age Factors↗