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Biomedical subjects

H Mikawa

Publications and source records attributed to H Mikawa.

At least 217 records · Page 12Linked to original sources
PubMed1987

Specific IgG antibodies to Dermatophagoides pteronyssinus and egg white--their changes with age.

Dermatophagoides pteronyssinus-specific and egg white-specific IgG in 232 children and 42 adults were measured by the RAST method using monoclonal anti-human IgG antibodies (HG2-25) as the secondary antibody. Changes in allergen-specific IgG with the age of the subjects were examined. Allergen-specific IgG antibody in standard serum was designated as 1,000 U/mL. Standard curves were made for each measurement and the levels of allergen-specific IgG of the sera were expressed in units (U). Dermatophagoides pteronyssinus-specific IgG increases from 9 months of age until adulthood. The atopic group showed higher mean values than the non-atopic group (r less than .001). Egg white-specific IgG reaches a peak around 3 to 4 years of age. After this, it declines until adulthood. These results suggest that age factors and allergen factors must be taken into consideration when evaluating allergen-specific IgG antibodies.

Adolescent↗
PubMed1986

Iron status in low birth weight infants on breast and formula feeding.

Iron status in 15 low birth weight infants, 1000-2499 g, on breast feeding was studied longitudinally for the first 6 months of age, and the findings compared to those of 30 low birth weight infants receiving a proprietary iron-fortified formula. The two groups received no iron supplement until they developed iron deficiency. The incidence of iron deficiency at 6 months was significantly greater in the breast-fed group than in the formula-fed group (86% v 33%). The breast-fed group had significantly lower serum ferritin and hemoglobin values after 4 months of age. The findings indicate that breast-fed low birth weight infants have a higher risk of developing iron deficiency and should receive iron supplementation from 2 months of age.

Age Factors↗
PubMed1986

Selective immunoglobulin M deficiency associated with disseminated molluscum contagiosum.

A 16-year-old girl with disseminated molluscum contagiosum (MC) was found to have a very low level of serum IgM, elevated levels of IgG and IgA, and a high level of IgE. She had normal numbers of peripheral blood IgM+, IgG+ and IgA+ B-lymphocytes but their terminal differentiation into plasma cells could not be induced by pokeweed mitogen (PWM) in vitro. On the other hand, the patient's T-cells showed normal helper functions in the PWM system and normal interferon (IFN) production in vitro. However, the IgM+ B-cells can be induced to differentiate into IgM secreting cells by Epstein-Barr virus (EBV), suggesting that the genetic mechanism for synthesis of the component immunoglobulin proteins is present. T-cell functions were impaired, as shown by delayed type cutaneous hypersensitivity (DTH) and mitogen response. The data suggest that the selective IgM deficiency of the patient is due mainly to defects in B-cells at the terminal differentiation stage, but immunological abnormalities are present in both B and T-cell systems. Neutrophil functions examined were normal. MC was treated by intravenous injection of IFN without any side effects; however, no clinical improvement was achieved.

Adolescent↗
PubMed1986

Regulation of synthesis of N-linked glycoproteins and their lipid intermediates in human T lymphoblastoid cells.

The synthesis of N-linked glycoproteins and their lipid intermediates was investigated in cell-free preparations of human T lymphoblastoid cells during two phases of cell growth. The incorporation of 14C-labeled Man into glycoproteins and dolichol-linked oligosaccharides was greater during the logarithmic growth phase than the stationary phase. The incorporation of 14C-labeled GlcNAc into dolichol derivatives was increased in the logarithmic phase. However, the synthesis of Dol-P-Man was not significantly different. These data suggest that the differences are due, at least partially, to the increased synthesis of Dol-P-P-GlcNAc.

Carbon Radioisotopes↗
PubMed1986

Possible role of neuraminidase in the pathogenesis of arteritis and thrombocytopenia induced in rats by Erysipelothrix rhusiopathiae.

The role of the neuraminidase produced by Erysipelothrix rhusiopathiae (E. rhusiopathiae) in the pathogenesis of arteritis and induced thrombocytopenia was examined using young and adult rats. There was a close correlation between bacterial invasion, desialation and cell infiltration in the common iliac artery. E. rhusiopathiae induced arteritis from the second and third day after inoculation with 3 X 10(8) viable bacteria in the young and adult rats, respectively. This delay with age was closely related to the increase of free sialic acid in the plasma. The sites invaded by E. rhusiopathiae coincided with the desialated lesions, and the bacteria invaded the periarterial region which was always accompanied by desialation when examined with FITC-conjugated peanut lectin. The free sialic acid in the plasma was, at least partly, considered to originate from the desialation of the arterial wall caused by E. rhusiopathiae. The platelet number decreased significantly after inoculation. The sialic acid content of the platelets prepared from circulating blood at 12 and 18 hours after inoculation showed a slight decrease and decreased further when the platelets were incubated with the bacteria. Platelets obtained from circulating blood within 24 hours after inoculation or incubated with the bacteria had demonstrated desialated sites as detected by immunofluorescent staining with FITC-conjugated peanut lectin. In conclusion, free sialic acid in the plasma was considered to be a good marker of the desialation of the arteries caused by E. rhusiopathiae, and the neuraminidase produced by the bacteria would be a key to solve the pathogenesis of the arteritis and thrombocytopenia.

Age Factors↗
PubMed1986

The effect of neonatal hyperbilirubinemia on the auditory brainstem response.

Auditory brainstem response (ABR) testing was performed on 30 babies in the Premature Baby Center of Kyoto University Hospital as soon after birth as possible. In cases of hyperbilirubinemia of more than 15.0 mg/dl, ABR testing was performed at least twice. In four babies with total bilirubin concentrations of more than 18.0 mg/dl at some point, abnormal ABRs were seen. These abnormalities normalized with a decrease in serum total bilirubin concentration in two of the four cases, but in the other two the abnormalities showed no change. The cause and significance of this difference are not known, but ABR is a simple and useful method for assessing the neurotoxic effects of bilirubin on the nervous system.

Audiometry, Evoked Response↗
PubMed1986

Asymmetrical head-turning of preterm infants: some effects on later postural and functional lateralities.

Asymmetrical head-turning and its effects on subsequent functional lateralities and postural asymmetries were examined in 44 relatively low-risk preterm and 53 fullterm infants. Persisting head-turning to the right was observed more often among preterm infants, as was an asymmetrical skull with flattened right occiput and head-turning to the right. Asymmetrical trunk posture was present in 20 preterm and four fullterm infants. At nine months right-hand preference was more marked in preterm infants, and hand preference was well coincident with head-turning. Changes in hand preference occurred more often among fullterm infants. Asymmetrical gait seemed to correlate with head-turning in preterm infants.

Functional Laterality↗
PubMed1986

Effect of C3 depletion on the genesis of thrombocytopenia induced in rats by Erysipelothrix rhusiopathiae.

The role of complement in the pathogenesis of marked thrombocytopenia induced in rats by Erysipelothrix rhusiopathiae (E. rhusiopathiae) was examined. In cobra venom factor (CoF)-treated rats thrombocytopenia was not induced by the bacterium. The content of 5-hydroxytryptamine (5-HT) in platelets was decreased significantly after inoculation only in untreated rats. E. rhusiopathiae could bind C3 and generate platelet-bacteria aggregation when incubated in the plasma diluted with veronal-buffered saline containing calcium and magnesium (VBS++) or gelatin-VBS containing magnesium and ethyleneglycol tetra-acetic acid (GVB-Mg-EGTA), but not when incubated in GVB-ethylenediamine tetra-acetic acid (GVB-EDTA) diluted plasma or in CoF-treated or anti rat C3-treated plasma. When platelets were preincubated with activated zymosan, no bacteria could bind to platelets. From the results, we speculate that the alternative complement pathway, activated by E. rhusiopathiae, appears to mediate the formation of platelet-bacterial aggregations that may accelerate the removal of platelets from circulating blood.

Animals↗
PubMed1985

gamma-Aminobutyric acid, benzodiazepine binding sites and gamma-aminobutyric acid concentrations in epileptic E1 mouse brain.

All E1 mice provoked by postural stimulation since the age of 4 weeks had convulsions between 22 and 24 weeks of age, the refractory period ranging from 20 to 30 min. As compared to ddY mice, the maximal number of high-affinity [3H]muscimol binding sites was larger and the affinity was lower in the brains of the E1 mice, which had or had not experienced repeated seizures caused by postural stimuli. The basal and gamma-aminobutyric acid (GABA)-stimulated [3H]flunitrazepam binding sites, and GABA concentration in the brains of the E1 mice did not differ from those of the ddY mice. In E1 mice following provoked convulsions, there were no temporary changes in [3H]muscimol binding, or [3H]flunitrazepam binding with or without exogenous GABA stimulation. The GABA concentration in the brains of the E1 mice increased immediately after seizures, and returned to the control values within 60 min.

Animals↗
PubMed1985

Inhibitor of 2',5'-oligoadenylate synthetase induced in human T lymphoblastoid cell line treated with deoxyadenosine, deoxycoformycin and interferon.

The effect of deoxyadenosine (dAdo) with deoxycoformycin on the induction of 2',5'-oligoadenylate synthetase by interferon was investigated. After semi-purification through poly(I):poly(C) gel, the activity was similar in control and dAdo-treated cells. However, the activity in the crude extract decreased with rising concentrations of dAdo. On the other hand, the level of 2'-phosphodiesterase, which is also induced by interferon and degrades 2',5'-oligoadenylate, showed no significant change after dAdo treatment. Thus, the crude extract was speculated to contain an inhibitor of 2',5'-oligoadenylate synthetase. Further characterization of the inhibitor revealed that inhibition was not due to dATP accumulation in cells.

2',5'-Oligoadenylate Synthetase↗
PubMed1985

Monoclonal anti-human IgG antibodies for quantitation of allergen-specific IgG in human sera.

Eight monoclonal anti-human IgG antibodies were fully characterized and evaluated as possible reagents in solid phase radioimmunoassay for quantitating allergen-specific IgG antibody. Four monoclonal antibodies (HG24D, HG2-14, HG2-18, and HG2-25) recognize CH2 domain of human IgG and bind to human IgG fixed to microtiter plate with high affinities. These monoclonal antibodies were more suitable than polyclonal rabbit anti-human IgG antibody in Phadebas RAST for honey bee venom-specific IgG antibody. Nonspecific binding was much lower, and the slopes of standard curves were much steeper. In contrast to polyclonal antibody, the standard curve was hardly influenced by human serum IgG in sample diluent. These advantages of monoclonal antibodies that recognize CH2 domain of human IgG made it possible to quantitate egg white- and Dermatophagoides pteronyssinus-specific IgG antibodies with use of allergen disks prepared for IgE RAST. This property allows a single system to be used for measurement of IgG and IgE antibodies against clinically relevant allergens.

Allergens↗
PubMed1985

Experimental arteritis in young rats induced by Erysipelothrix rhusiopathiae.

The acute phase of arteritis of the common iliac artery induced in young rats by the inoculation of viable Erysipelothrix rhusiopathiae (E. rhusiopathiae) was examined. Within three days post inoculation, cell infiltration was first detected in the periarterial tissue, extending centripetally to the outer two-thirds of the media. However, the inner third of the media and the intima were free from cell infiltration, and the media showed no degeneration. E. rhusiopathiae first invaded the periarterial tissue and the adventitia, thereafter, invaded the outer two-thirds of the media, but not the inner third of the media or the intima. Invasion by the bacteria preceded cell infiltration. Arteritis was not induced by heat killed bacteria or the supernate from the culture medium. The arteritis was produced preferentially in large or medium-sized muscular arteries. Immunofluorescence test by FITC-conjugated peanut lectin demonstrated the desialated sites by the effect of the neuraminidase produced by E. rhusiopathiae in the arterial region that were concomitant with the invasion of the bacteria. C3 was also detected along the adventitia of the artery. The results demonstrated that viable E. rhusiopathiae can induce arteritis of muscular arteries and that the neuraminidase produced by the bacteria may play a role in the pathogenesis.

Animals↗
PubMed1985

Prognosis and treatment of polymyositis with particular reference to steroid resistant patients.

Eight boys and six girls with polymyositis examined between 1967 and 1982 were studied. The mean age of disease onset was 5 years 5 months. The initial regimen was prednisolone, 1.2 to 2.3 mg/kg/day, and after four weeks this dose was decreased gradually to a maintenance level of 5 to 20 mg on alternate days. The total treatment period was 3 years 6 months on average. Eleven of the 14 children had a uniphasic course, and steroids were stopped without a resurgence of the disease: three were refractory to steroid treatment. One of these died of a cardiomyopathy seven years after the onset of the illness despite treatment with steroids and cyclophosphamide; the second was treated with adrenocorticotrophic hormone after prednisolone, but without benefit; and in the third a series of treatment with lympho-plasmapheresis and cyclophosphamide resulted in some improvement. As cardiac involvement in polymyositis may become overt if the disease persists for many years, patients refractory to steroids should be given alternative treatment.

Adolescent↗