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Biomedical subjects

A Morikawa

Publications and source records attributed to A Morikawa.

At least 91 records · Page 5Linked to original sources
PubMed1999

Allelic variations of the D2 dopamine receptor gene in children with idiopathic short stature.

The D2 dopamine receptor (DRD2) plays a major role in growth hormone (GH) secretion. Recent reports indicate that Taq I A DRD2 gene alleles (A1 and A2) are related to the function of DRD2. Idiopathic short stature (ISS) is defined as short stature without accompanying malnutrition, chronic disease, and endocrinological disorders. However, some reports suggest that ISS is associated with a mild disturbance of GH secretion. In this study, we examined the notion that allelic variants of the DRD2 are associated with ISS. We studied 55 children with ISS aged 8.4 (SD 2.9) years; (group I) and 104 age-matched children of normal stature (group II). Informed consent was obtained from each child's parent or guardian. Genomic DNAs were extracted from peripheral mononuclear cells and amplified by polymerase chain reaction (PCR). The PCR products were digested by Taq1 and resolved by electrophoresis. The frequency of the A1 allel was significantly higher in group I (0.42) than in group II (0.26). The insulin-like growth factor (IGF)-I ratio (the ratio of the individual level to the normal mean value according to age at our laboratory center) was significantly lower in group I than in group II. When group I was subdivided into group A (with the A1 allele) and group B (with only the A2 allele), group A had a significantly lower peak GH response to the l-dopa test, lower levels of IGF-I, and retarded bone maturation. These findings indicate that polymorphism of the DRD2 gene may be one genetic factor that affects body height in childhood, acting through the hypothalamus (GH-releasing hormone)--pituitary (GH)--IGF-I axis.

Alleles↗
PubMed1999

Corticosteroids in the treatment of the acute phase of Kawasaki disease.

OBJECTIVES: Corticosteroids are considered to be contraindicated during the acute phase of Kawasaki disease (KD) based on unfavorable results in early studies. In our hospital, however, corticosteroids have been used in some cases of KD with satisfactory results. We analyzed outcomes of patients with KD treated with or without corticosteroids. STUDY DESIGN: Medical records of 299 children with KD treated with one of the 4 regimens were reviewed retrospectively. Regimen 1 consisted of aspirin, dipyridamole, and propranolol; regimen 2 was regimen 1 plus prednisolone, 2 mg/kg/d, for 1 week, followed by tapering over 2 weeks; regimen 3 was regimen 1 plus intravenous gamma-globulin (IVGG), 200 or 400 mg/kg/d, for 5 consecutive days; and regimen 4 was regimen 1 plus both prednisolone and IVGG. RESULTS: Although patients treated with regimens 2 and 4 were more ill at presentation than those treated with regimens 1 and 3, respectively, the duration of fever was shorter in the former patient groups (P =.0013). Coronary aneurysms developed least frequently in patients treated with regimen 4 and less frequently with regimen 2 than with regimen 1 (P =.0730). Multiple regression analysis showed significant reductions of fever and coronary aneurysm incidence with prednisolone (P <.0001 and P =.0307, respectively). CONCLUSION: Our data suggest a possible role of corticosteroids in the treatment of the acute phase of KD.

Acute Disease↗
PubMed1999

Experimental murine model for autoimmune enterocolitis using Klebsiella pneumoniae O3 lipopolysaccharide as a potent immunological adjuvant.

An experimental model for autoimmune enterocolitis was produced in mice by repeated immunization of homologous colon extract together with Klebsiella 03 lipopolysaccharide (KO3 LPS) as an immunological adjuvant. Histological changes in the intestinal lesions were characterized by infiltration with polymorphonuclear leukocytes in the lamina propria, muscularis mucosae and submucosa of repeatedly immunized mice. No such intestinal lesions were produced in mice receiving injections of colon extract alone or KO3 LPS alone. Development of the autoantibody and delayed-type hypersensitivity against colon extract were found in mice immunized with the mixture of colon extract and KO3 LPS. Distinct positive staining was detected specifically on the columnar epithelium of villi. Sera from hyperimmunized mice defined organ-specific antigens present in the intestine. Therefore, it was suggested that the intestinal lesions might be caused by an autoimmune mechanism.

Adjuvants, Immunologic↗
PubMed1999

Gastrointestinal sounds and migrating motor complex in fasted humans.

OBJECTIVE: We investigated the relationships among gastrointestinal sounds, gastrointestinal manometric findings, and small intestinal transit time in healthy fasted humans. METHODS: Gastrointestinal sounds acquired with two microphones attached to the upper and lower abdominal walls of healthy subjects were quantified with a computer-aided sound analysis program. Antroduodenal contractions were recorded by manometry. Small intestinal transit time was measured by breath hydrogen testing after intraduodenal administration of lactulose. RESULTS: The sum of the gastrointestinal sound amplitudes (sound index) in both the upper and lower abdomen changed with time, coinciding with the gastric phases of the migrating motor complex. The sound indices in the upper and lower abdomen were 59.0+/-24.8 and 98.1+/-21.6 mV/min in phase 1, 95.5+/-27.9 and 127.4+/-34.9 mV/min in phase 2, and 132.8+/-12.4 and 188.5+/-73.4 mV/min in phase 3, respectively. There were no significant differences among motility phases in terms of the mean duration or frequency of each sound event. Intravenous erythromycin induced phase 3 in the stomach and doubled the sound index. Somatostatin analogue induced phase-3-like clustered contractions in the duodenum, but inhibited antral contractions and decreased the sound index. The small intestinal transit time was shorter and the sound index increased after intravenous metoclopramide, compared with controls. Scopolamine delayed small intestinal transit time and decreased the sound index. CONCLUSIONS: This study is the first to document the relationships between gastrointestinal sounds and the migrating motor complex. The chronological relation between antral motility and gastrointestinal sounds, and the dissimilar effects of erythromycin and somatostatin, suggest that antral contractions increase gastrointestinal sounds, perhaps by supplying gas into the intestine.

Adult↗
PubMed1999

Role of nitric oxide in lipopolysaccharide-induced hepatic injury in D-galactosamine-sensitized mice as an experimental endotoxic shock model.

The role of nitric oxide (NO) in lipopolysaccharide (LPS)-induced hepatic injury was studied in D-galactosamine (D-GalN)-sensitized mice. The inducible isoform of NO synthase (iNOS) was immunohistochemically detected on hepatocytes around blood vessels in livers of mice injected with D-GalN and LPS not on hepatocytes in mice injected with D-GalN or LPS alone, although mRNA for iNOS was found in those mice. Nitrotyrosine (NT) was also found in livers of mice injected with D-GalN and LPS. The localization of NT was consistent with that of iNOS, and the time courses of NT and iNOS expression were almost the same. Expression of iNOS and NT was detected exclusively in the hepatic lesions of mice injected with D-GalN and LPS. Anti-tumor necrosis factor alpha neutralizing antibody inhibited iNOS and NT expression and hepatic injury. The results suggested that NO from iNOS may play a role in LPS-induced hepatic injury on D-GalN-sensitized mice as an experimental endotoxic shock model.

Animals↗
PubMed1999

Expression of Fas and Fas ligand on mouse renal tubular epithelial cells in the generalized shwartzman reaction and its relationship to apoptosis.

Previously we reported that the consecutive injection of lipopolysaccharide (LPS) into LPS-sensitized mice for the generalized Shwartzman reaction (GSR) appeared to induce the injury of renal tubular epithelial cells via apoptosis. The aim of this study was to characterize the mechanism of renal tubular epithelial cell injury in GSR. The expression of Fas and Fas ligand was immunohistochemically detected on renal tubular epithelial cells from GSR-induced mice, although neither Fas nor Fas ligand was found in cells from untreated control mice or in cells from mice receiving a single injection of LPS. GSR-induced renal tubular epithelial cell injury was produced in neither Fas-negative MRL-lpr/lpr mice nor Fas ligand-negative MRL-gld/gld mice. The administration of anti-gamma interferon antibody together with a preparative injection of LPS prevented the expression of Fas and Fas ligand and the apoptosis of renal tubular epithelial cells. A provocative injection of tumor necrosis factor alpha into LPS-sensitized mice augmented Fas and Fas ligand expression and the apoptosis of renal tubular epithelial cells. The administration of tumor necrosis factor alpha to interleukin-12-sensitized mice resulted in Fas and Fas ligand expression and the apoptosis. Sensitization with interleukin-12 together with anti-gamma interferon antibody did not cause the apoptosis of renal tubular epithelial cells. It was suggested that the Fas/Fas ligand system probably plays a critical role in the development of renal tubular epithelial cell injury through apoptotic cell death.

Animals↗
PubMed1999

Effect of ultrasonically nebulized distilled water on airway epithelial cell swelling in guinea pigs.

To investigate the pathogenesis of ultrasonically nebulized distilled water-induced airway narrowing, we studied the role of airway epithelial cells during a distilled water-inhalation challenge in an animal model of airway inflammation. Guinea pigs were divided into four groups: 1) a sham/saline (S/S) group: sham ozone followed by saline inhalation; 2) a sham/water (S/W) group: sham ozone followed by water inhalation; 3) an ozone/saline (O/S) group: ozone followed by saline inhalation; and 4) an ozone/water (O/W) group: ozone followed by water inhalation. After exposure to either 3.0 parts/million ozone or air at the same flow rate for 2 h, guinea pigs were anesthetized and tracheostomized, and then lung resistance (RL) was measured. For morphometric assessment, tissues were fixed with formaldehyde, stained with hematoxylin and eosin, and cut into transverse sections. Airway dimensions were either measured directly or calculated from the internal perimeter, the external perimeter, and airway wall area. There were no statistical differences in the values of RL before distilled water inhalation between the sham groups and the ozone groups. RL increased significantly after 10 min of distilled water inhalation in both the S/W group and the O/W group. In the S/W group, epithelial cells were swollen, and intercellular spaces were wider, resulting in significant increase in epithelial wall thickness, but there was no significant infiltration by inflammatory cells. In the O/S group, the epithelium showed infiltration by inflammatory cells without change in cell volume. In the O/W group, the epithelium showed both infiltration and a greater increase in epithelial wall thickness compared with the S/W group. These results suggest that airway epithelial cell swelling, induced by inhaled distilled water, increases with RL in guinea pigs and that this reaction may be accelerated by airway inflammation.

Administration, Inhalation↗
PubMed1999

Effect of age and weaning on gastric mucosal injury in developing rats.

We evaluated ethanol- and HCl-induced mucosal damages in developing rats. The degree of damage induced by ethanol and HCl was greatest in 1-week-old rats and decreased significantly with age until 4 weeks; thereafter it increased again. To evaluate the effect of weaning on the maturational changes in mucosal defense, we compared ethanol-induced mucosal damage among three groups of newborn rats: (1) receiving milk only; (2) receiving only rat chow from 14 days of age, and (3) having free access to milk and chow. There were no significant differences at 18 and 21 days of age. The mucus thickness increased with age until 8 weeks and was not affected by weaning. In conclusion, developmental changes occur in gastric mucosal protection in rats. Weaning does not have a significant effect on these changes.

Aging↗
PubMed1999

Role of serum leptin in the regulation of weight gain in early infancy.

We investigated the changes in the serum leptin concentration from birth to 30 days of age in order to determine the effects of leptin in early infancy. Twenty-seven Japanese term infants (12 boys and 15 girls) were examined. The serum leptin concentration at 3-6 days of age was significantly lower than that in cord blood (p < 0.0001) and was significantly higher at 30 days than at 3-6 days (p < 0.0001). The serum leptin concentration did not differ with gender or nutrition. The body weight gain and the magnitude of leptin rise that occurred between 3-6 and 30 days of age showed a significant positive correlation (r = 0.79; p < 0.0001). These changes in leptin levels suggest that leptin plays an important role in the regulation of weight gain in early infancy.

Aging↗
PubMed1999

Intracellular signaling pathways in human eosinophil activation: role of a beta2 integrin, alphaMbeta2.

Cellular adhesion is crucial roles for eosinophil effector functions such as degranulation. Here, we focused on the role of a beta2 integrin, alphaMbeta2, in intracellular signaling pathways of human eosinophil activation. We found that the ligation of alphaMbeta2 triggers the activation of an intracellular signaling cascade, including protein tyrosine phosphorylation and phosphoinositide turnover, and subsequent cellular degranulation in human eosinophils. These signaling events may play important roles in adhesion-dependent cellular functions of eosinophils.

Cell Adhesion↗
PubMed1999

Difference in airway reactivity in children with atopic vs nonatopic asthma.

STUDY OBJECTIVE: To examine the difference in the mechanisms of bronchial hyperresponsiveness (BHR) in nonatopic asthma and in atopic asthma, we studied bronchial reactivity against nonspecific stimuli in children with atopic asthma and nonatopic asthma. DESIGN AND PARTICIPANTS: Fourteen children with nonatopic asthma, 24 children with atopic asthma, and 20 age-matched controls participated in this study. MEASUREMENTS: Inhalation challenge was performed by administering progressively doubling doses of methacholine with a continuous inhalation provocation method. The speed of bronchoconstriction to methacholine (Sm) and the speed of reversal of bronchoconstriction to methacholine after inhalation of a beta2-agonist (r-Sm), which was considered to represent the effect of the beta2-agonist, were calculated from the dose-response curve. RESULTS: The value of Sm was higher in the nonatopic asthma group than in the atopic asthma group and the control group. The value of r-Sm was also higher in the nonatopic asthma group than in the atopic asthma group, but did not differ from that in the control group. CONCLUSION: These results indicate that bronchial reactivity against methacholine and the beta2-agonist was greater in nonatopic asthma than in atopic asthma, and that the mechanism of BHR in children with nonatopic asthma may differ from that in children with atopic asthma.

Adolescent↗
PubMed1999

Analysis of gastrointestinal sounds in infants with pyloric stenosis before and after pyloromyotomy.

BACKGROUND: Although recent advances in computer technology enable us to analyze gastrointestinal sounds data objectively with ease, this clinical application has been investigated in only a few disorders. To investigate one potential role of this approach in pediatric practice, we recorded and analyzed gastrointestinal sounds in infants with hypertrophic pyloric stenosis (HPS), a motility-related disorder that is common in children. METHODS: In 15 infants with pyloric stenosis, gastrointestinal sounds were collected with a microphone placed 3 cm below the umbilicus for 60 minutes before pyloromyotomy and at 9 to 12 hours, 20 to 24 hours, 40 to 48 hours, and 112 to 120 hours after the operation. Data were entered into a computer to sum the amplitude of sound signals as a sound index (SI; mV per minute). In 12 infants, gastric emptying was measured immediately before each sound recording, using a marker dilution-double sampling method. RESULTS: Before surgery, the mean SI was 4.6 +/- 1.0 mV per minute, significantly less than in healthy controls (31.7 +/- 8.4 mV per minute). The SI remained in a similar range until 12 hours after operation, after which it began increasing to reach the normal range by 48 hours after operation (30. 0 +/- 9.4 mV per minute). Gastric emptying, also low in HPS before pyloromyotomy, increased by 4 to 5 times after surgery. There was a significant positive correlation between SI and gastric emptying. The incidence of postoperative symptoms (such as vomiting) were correlated significantly with SI at 24 hours after surgery. CONCLUSION: This study found decreased gastrointestinal sounds to be among physical findings suggestive of HPS and a useful indicator of gastric emptying and bowel motility after pyloromyotomy. Computer-assisted analysis of gastrointestinal sounds might be helpful in clinical practice for pediatric patients with some gastrointestinal disorders.

Analysis of Variance↗
PubMed1999

Bronchial reactivity to inhaled methacholine in infants with asthma and age-matched controls.

To evaluate bronchial hyperresponsiveness (BHR) in infants with asthma and the influence of aging on BHR during the infantile period, bronchial reactivity to inhaled methacholine (BRm) in infants was monitored using the transcutaneous oxygen pressure (tcPO2) method. One hundred thirty-seven infants with asthma (from 1 to 5 years, mean 3.4 years) and 97 age-matched children without chronic respiratory diseases (from 6 months to 5 years, mean 2.1 years) were enrolled in this study. Consecutive doses of methacholine were doubled until a 10% decrease in tcPO2 from the baseline was reached. The cumulative dose of methacholine at the inflection point of tcPO2 (Dmin-PO2) was considered to represent the reactivity of tcPO2 to inhaled methacholine. Dmin-PO2 values in the asthma groups were lower than those in the control groups in each year-group from 1 to 5. There was no statistical difference in Dmin-PO2 among the 1-4-year-old asthma groups, but Dmin-PO2 in the 5-year-old asthma group was significantly lower than Dmin-PO2 in the 1-4-year-old asthma groups. The same age-related change in Dmin-PO2 was also seen in the control groups. There was no difference in age-related Dmin-PO2 change between the female group and the male group. We concluded that BRm in asthmatic children increases during the infantile period, and that the age-related changes in BRm, observed in both asthmatic and control infants, may have an effect on the clinical symptoms of asthma during childhood.

Age Factors↗
PubMed1999

[Cranio-cervical junction dural arteriovenous malformation presenting with subarachnoid hemorrhage: report of two cases].

Most spinal dural arteriovenous malformations (AVMs) affect the thoracic and lumbar regions. The clinical features of dural AVMs are, usually, gradually progressing myelopathy, while hemorrhage is a rare occurrence. We have recently encountered two cases of cranio-cervical junction dural AVM which caused subarachnoid hemorrhage. Both patients, a 61-year-old and a 37-year-old man were admitted to our hospital due to sudden onset of severe headache. Left vertebral angiography demonstrated a dural AVM at the cranio-cervical junction. A left suboccipital craniotomy and left hemilaminectomy of the atlas were performed. Dural opening disclosed tortuous dilated abnormal vessels. The dural AVM was fed by multiple small dural branches of the left vertebral artery and drained into an intracranial pial vein. The dura where the left vertebral artery penetrated was coagulated and divided from the left vertebral artery. Postoperative courses of these patients were uneventful. The pathophysiology and surgical treatment of dural AVMs in the cranio-cervical junction are discussed.

Adult↗