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Biomedical subjects

H Asada

Publications and source records attributed to H Asada.

At least 73 records · Page 4Linked to original sources
PubMed1998

Falloposcopic tuboplasty for bilateral tubal occlusion. A novel infertility treatment as an alternative for in-vitro fertilization?

The linear everting (LE) catheter has been developed to safely guide a Falloposcope into the entire length of Fallopian tube in order to observe the tubal lumen. It may also be useful therapeutically for the recanalization of occluded tubes. Fifty infertility patients who had been diagnosed with proximal, mid and distal tubal occlusion by hysterosalpingogram, Rubin test and hysteroscopic selective hydrotubation, were selected to undergo Falloposcopic tuboplasty (FT). Patients having hydrosalpinges were excluded from the study group. The total number of tubes treated was 102 during 53 FT procedures. On the basis of tubes attempted, the LE catheter successfully accessed 85.3% (87/102). A follow-up hysterosalpingogram was completed 1-3 months following the FT procedure, which revealed an overall patency rate of 79.4% (81/102). During FT, a high incidence of multiple adhesions was observed in the entire length of tubal lumen in patients having bilateral occlusions. To date, the total number of pregnancies following FT treatment is 11 over a follow-up period of 2 months to 3 years. FT has been established as a highly useful, less invasive and novel treatment for tubal infertility. This technique may be useful in selected patients with tubal infertility.

Catheterization↗
PubMed1998

Immunoradiometric assay for the N-terminal fragment of proatrial natriuretic peptide in human plasma.

Recently, the N-terminal fragment of proatrial natriuretic peptide (N-terminal proANP) has been proposed as a marker of chronic congestive heart failure. In this study, we established a two-step immunoradiometric assay using monoclonal antibodies and synthetic N-terminal proANP (1-67) as a standard. It allows us to measure plasma N-terminal proANP in only 4 h without prior extraction. The detection limit of this assay was 15 pmol/L for a 100 microL sample of plasma. Within-run CVs ranged from 1.7% to 2.9% and between-run CVs ranged from 4.2% to 5.1%. The dilution curves of plasma samples showed good linearity and analytical recovery was 89-104%. The mean (+/-SD) N-terminal proANP in plasma of 33 healthy subjects was 188 (+/-71) pmol/L and 1030 (+/-411) pmol/L in 25 patients with heart failure. Our immunoradiometric assay is rapid and precise enough for routine determination of N-terminal proANP in human plasma.

Antibodies, Monoclonal↗
PubMed1997

Productive infection of dendritic cells by HIV-1 and their ability to capture virus are mediated through separate pathways.

There is substantial evidence that dendritic cells (DC) residing within epithelial surfaces (e.g., Langerhans cells) are the initial cells infected with HIV after mucosal exposure to virus. To study DC-HIV interactions in detail, we propagated Langerhans cell-like DC from cord blood CD34(+) cells and from adult blood plastic-adherent PBMC in the presence of cytokines (GM-CSF, IL-4, and/or TNF-alpha). DC pulsed overnight with HIVBaL or HIVIIIB were infected productively with both viral subtypes (as assessed by PCR, supernatant p24 protein levels, electron microscopy, and antibody staining). Productive infection could be blocked by anti-CD4 mAbs, RANTES (regulated upon activation, normal T cell expressed and secreted) (for HIVBaL), stromal cell-derived factor-1 (for HIVIIIB), or azidothymidine added during the HIV pulse, as well as by blocking DC proliferation. However, pulsing DC with HIV under these blocking conditions had no effect on the ability of DC to capture virus and transmit infection to cocultured antigen-stimulated CD4(+) T cells. Thus, we show by several criteria that (a) productive infection of DC and (b) the ability of DC to capture virus are mediated through separate pathways. We suggest that strategies designed to block mucosal transmission of HIV should consider interfering with both virus infection and virus capture by DC.

Antigens, CD34↗
PubMed1997

Cleft palate and decreased brain gamma-aminobutyric acid in mice lacking the 67-kDa isoform of glutamic acid decarboxylase.

In addition to its role as an inhibitory neurotransmitter, gamma-aminobutyric acid (GABA) is presumed to be involved in the development and plasticity of the nervous system. GABA is synthesized by glutamic acid decarboxylase (GAD), but the respective roles of its two isoforms (GAD65 and 67) have not been determined. The selective elimination of each GAD isoform by gene targeting is expected to clarify these issues. Recently we have produced GAD65 -/- mice and demonstrated that lack of GAD65 does not change brain GABA contents or animal behavior, except for a slight increase in susceptibility to seizures. Here we report the production of GAD67 -/- mice. These mice were born at the expected frequency but died of severe cleft palate during the first morning after birth. GAD activities and GABA contents were reduced to 20% and 7%, respectively, in the cerebral cortex of the newborn GAD67 -/- mice. Their brain, however, did not show any discernible defects. Previous pharmacological and genetic investigations have suggested the involvement of GABA in palate formation, but this is the first demonstration of a role for GAD67-derived GABA in the development of nonneural tissue.

Aging↗
PubMed1997

Trauma-induced striatal CNTF and BDNF mRNA in hemiparkinsonian rats.

Surgical implantation of tissues into the brain causes trauma to the region receiving the graft. This study shows that real or simulated striatal trauma in hemiparkinsonian rats leads to increased expression of two trophic factor mRNAs: ciliary neurotrophic factor (CNTF) and brain-derived neurotrophic factor (BDNF). The baseline expression of BDNF mRNA was also markedly lower in dopamine-depleted striatum than in normal striatum in non-traumatized (control) hemiparkinsonian rats. Striatal CNTF message was relatively symmetrical in the non-traumatized (control) hemiparkinsonian rats. Host production of these and other trophic factors may play important roles in the response to tissue grafting, to enhance graft survival and as a stimulus to regenerative collateral axonal sprouting.

Animals↗
PubMed1997

Cytokine gene expression during the elicitation phase of contact sensitivity: regulation by endogenous IL-4.

Recent studies have focused on characterizing the cytokine profile produced in the epidermis during the sensitization phase of contact sensitivity (CS). Some prior studies have also identified altered individual cytokine mRNA profiles in skin or draining lymph nodes (or several cytokine mRNA profiles in the epidermis) during the elicitation phase of CS. In this study we determined the dynamics of appearance of a battery of cytokine mRNA levels in both the epidermis and dermis during the elicitation phase of CS. We isolated mRNA from dispase-separated epidermis and dermis of TNCB-sensitized and naive BALB/c mice at various times after TNCB challenge. Changes in IFN-gamma and IL-4 mRNA levels (by semiquantitative RT-PCR) were more reproducible and dramatic than those of other cytokines studied (IL-1beta, IL-2, IL-10, and IL-12 p40). Compared to naive mice, sensitized mice had significantly elevated IL-4 mRNA signals 9 and 24 h (dermis), and 24 h (epidermis), after TNCB challenge. The increased IL-4 mRNA levels were mast-cell-independent, because sensitized mast-cell-deficient mice showed similar increases in IL-4 mRNA. To examine the role of endogenous IL-4 in CS elicitation, sensitized mice were treated with anti-IL-4 mAb 1 h before challenge. In accord with prior studies, anti-IL-4 mAb-pretreated mice showed increased ear swelling 24 h after challenge compared to mice pretreated with isotype control mAb. Anti-IL-4 mAb pretreatment also enhanced IFN-gamma, IL-2, IL-12 p40, and IL-1beta (but not IL-10) mRNA signals in the dermis of sensitized and challenged mice. These data indicate that IL-4 is produced in murine skin during the elicitation phase of CS and is an important down-modulator of inflammation. IL-4 may blunt CS by regulating local production of proinflammatory cytokines.

Animals↗
PubMed1997

OK-432 therapy for recalcitrant warts.

Twelve patients with warts recalcitrant to various treatment, including cryotherapy, were treated with OK-432 injection therapy. Six patients received only subcutaneous injection, three received only intralesional injection, and the other three received both subcutaneous and intralesional injections. Complete clearing of the warts occurred in nine (75%) of 12 patients, while the other three patients were not cured. Grouping the patients by the method of injection, the success rate of subcutaneous injection was 5/9 (55.6%), and that of intralesional injection was 4/6 (66.7%). Although five patients complained of mild fever and malaise, these side effects gradually disappeared during the repeated injections. OK-432 injection is considered as a hopeful therapy for recalcitrant warts.

Adolescent↗
PubMed1997

Gender differences in effects of 20 days horizontal bed rest on muscle strength in young subjects.

Gender differences in the effect of 20 days bed rest (BR) on muscle strength were evaluated in voluntary 11 male and 7 female students. Maximum Isometric Voluntary Contractions (MVC) of 4 right arm muscles (RAM), 5 right leg muscles (RLM), and 2 body trunk muscles were measured with an isometric dynamometer, respectively. Muscle masses (MM) of right arm and leg and body trunk were determined by dual energy X-ray absorptiometry, respectively. The maximum cross sectional area (CSAmax) of right m. quadriceps femoris was measured by magnetic resonance imaging. Elbow flexion MVC in males and all MVC of RLM except knee flexion in both males and females were decreased (p<0.05), but elbow extension MVC in females was increased (p<0.05), while all of other MVC only tended to decrease. However, the decrements in leg MVC were not correlated to the leg MM, and also the decrement in knee extension was not correlated to the CSAmax of m. quadriceps. The reduction of MVC of antigravity muscles might be caused not only by a decrease in MM but also by other factors. The greater decrements of leg MVC during BR were the higher initial level in males, but the inverse was observed in females. However, this discrepancy between males and females cannot be explained in the present study.

Adolescent↗
PubMed1997

Effects of 20 days horizontal bed rest on maintaining upright standing posture in young persons.

The effects of 20 days horizontal bed rest (BR) on postural reflex were studied by measuring fluctuation of center of gravity in the body during two legs or one leg upright standing in 10 young volunteers. The fluctuation was decided as total moving distance of the center recorded during 60sec standing on a force plate. The stability was measured by the moved area. After BR, the moving distance increased during two legs standing with open eyes (p<0.05), but statistically unchanged with closed eyes. The moving area decreased during right one-leg standing with closed eyes (p<0.05), but unchanged during left one-leg standing. Despite with open eyes the increased distance suggested that postural reflexes to maintain upright position were probably decreased by increased unsuitable feedback informations from the visual receptor deconditioning during BR. The decreased area during right one-leg standing with closed eyes also suggested that the declined standing posture reflex was probably related to more rapidly lowered functions for maintaining standing position in the dominating leg than in the other.

Adult↗
PubMed1997

Effects of 20 days horizontal bed rest on kinesthesia during knee flexion and two-point discrimination in skin of young subjects.

Investigating the effect of 20 days bed rest (BR) on kinesthesia and two-point discrimination, 10 young volunteers participated in this study as subjects. Angle position sensation of right knee was measured in the prone position during flexion and extension monitored by a goniometer after two-point discrimination in skin was determined on the same lower leg. Flexed constant error was unchanged but directional constant error and absolute error were increased after BR (p<0.05). Two-point discrimination was unchanged after BR, which brought about a decline of the orientation of moving the joint indicated as over shooting of the angle during knee flexion, while it did not affect superficial sensation observed by two-point discrimination. Probably, an adjustment of deep sensation to the knee joint is lowered by the reduction in kinesthesia as well as the sensory disturbance during BR, which is independent on information from superficial sensation.

Adult↗
PubMed1996

Mice lacking the 65 kDa isoform of glutamic acid decarboxylase (GAD65) maintain normal levels of GAD67 and GABA in their brains but are susceptible to seizures.

The gene encoding of the 65 kDa isoform of the gamma-aminobutyric acid (GABA)-synthesizing enzyme, glutamic acid decarboxylase (GAD), GAD65, was targeted in mice by homologous recombination. Viable GAD65 -/- mice were obtained with the expected mendelian frequency and displayed no gross morphological defects. Despite the complete loss of GAD65 mRNA and protein in a homozygous mutant, there was no difference in GABA content in the brains of GAD65 +/+, +/-, and -/- mice. As for the other 67 kDa isoform (GAD67), the levels of mRNA and protein were largely unchanged by the GAD65 mutation. General behavior, including locomotor activity and performance in the Morris water maze task, appeared normal, but seizures were more easily induced by picrotoxin and pentylenetetrazol: the latencies to seizures induced by picrotoxin were shorter and the dose of pentylenetetrazol required for induction of seizures was lower.

Animals↗
PubMed1996

In vitro assessment of neurotrophic activity from the striatum of aging rats.

Neurotrophic factors are produced in the striatum following trauma and have a demonstrable effect on in vitro bioassays and on in vivo graft survival. We have previously measured the in vitro effect of these factors following trauma to the striatum of young rats. However, the effect of age on this neurotrophic response has not been evaluated. In this study we report on the in vitro effects of extracts (obtained from gelfoam) removed from striatal cavities 7 days following trauma. Gelfoam extract from aged rats (18-24 months) had a reduced neurite-promoting response in dorsal root ganglia (DRG) and SH-SY5Y (a dopamine-producing neuroblastoma cell line) assays, compared to gelfoam from young rats (2-3 months). In contrast, extracts from both young and old rats showed significant neuroprotection of SH-SY5Y cells from the dopaminergic neurotoxins N-methy-4phenylpyridinium ion (MPP +) and 6-hydroxydopamine (6-OHDA). The results suggest that the striatum of aged individuals may have (1) a diminished capacity of neurite promotion and/ or (2) that neurite outgrowth and neuroprotection may be influenced by different factors or different levels of the same factors. The direct implication is that aged animals would be the most appropriate models to study experimental therapies for Parkinson's disease.

1-Methyl-4-phenylpyridinium↗
PubMed1996

Familial Alzheimer's disease-linked mutations at Val717 of amyloid precursor protein are specific for the increased secretion of A beta 42(43).

In some pedigrees of familial Alzheimer's disease (FAD), three mutations of beta amyloid precursor protein (APP) have been found at the Val717 residue (to Ile, Phe, or Cly) and these mutations increase the secretion of A beta 42(43). To study the specificity of the effects of these mutations on APP processing, we transiently expressed APP genes with mutations of Val717 to Lys, Ser, Glu, or Cys in COS cells. The three familial AD-linked mutations increased the levels or ratios of A beta 42(43), whereas the secretion of A beta 40 was decreased. Other mutations irrelevant to FAD except Val717 to Lys had little effect on the ratio of A beta 42(43). Substitution to Lys decreased the secretion of A beta 42(43); substitution to Glu or Gly decreased the amount of intracellular C-terminal fragment produced by alpha-secretase, whereas it was increased by mutations to Phe, Cys, or Lys. However, the levels of secretion of soluble APP were constant, but a substitution to Glu reduced it. These results suggest a specific role of the Val717 residue in APP processing and, especially, in gamma-cleavage.

Alzheimer Disease↗
PubMed1996

Relation of abnormal burst activity of spinal neurons to the recurrence of autotomy in rats.

Two groups of rats received different amounts of peripheral deafferentations; one group received sections of sciatic nerve (S-rats) and the other received sections of sciatic and saphenous nerves (SS-rats). In Experiment 1 the occurrence of autotomy was compared between S- and SS-rats for up to 70 days after the surgery. Autotomy in SS-rats frequently recurred until 40 days after denervation whereas in S-rats it scarcely recurred. In Experiment 2 spontaneous activity was recorded from the spinal cords in S- and SS-rats, and the proportion of burst firing cells (B-cells), characterized by periodic and high frequency bursts, was compared. In both S- and SS-rats with fresh wounds the occurrence of B-cells was high until 40 days after denervation. However, B-cells were still frequently observed in SS-rats with old wounds until 40 days after denervation, whereas B-cells were scarcely found in S-rats with similar old wounds. This finding corresponded well with the behavioral observation in Experiment 1. The data strongly suggests that the continuance of a high proportion of B-cells in the spinal cord plays an essential role for the induction of recurrent autotomy.

Afferent Pathways↗
PubMed1996

Stabilization of adhesion plaques by the expression of drebrin A in fibroblasts.

The expression of drebrin A was induced in mouse fibroblasts (L cells) after transformation of cells with a vector that carried cDNA for rat drebrin A (developmentally regulated brain protein A) under the control of the promoter of the gene for metallothionein-I. When drebrin was expressed in the transformed cells (MTI-5 cells), the organization of actin filaments changed such that stress fibers were converted to a mesh-like structure. After subsequent treatment with 5 micrograms/ml cytochalasin D (a reagent that depolymerizes actin filaments), MTI-5 cells maintained their shape, while cells of a drebrin-negative cell line, MTI-11, formed retraction processes. Simultaneously, actin filaments changed into patchy dot-like aggregates in the cytoplasm of both MTI-5 and MTI-11 cells. These aggregates are known as cytoplasmic pools. In MTI-5 cells, adhesion plaques that were resistant to treatment with cytochalasin D appeared upon expression of drebrin. These adhesion plaques were immunostained with vinculin-specific antibodies, while those in MTI-11 cells were hardly immunostained. The amount of vinculin in MTI-5 cells increased in parallel with increase in the level of drebrin. These results suggest that expression of drebrin A induces changes in the assembly of actin filaments and adhesion plaques, with resultant modulation of cellular adhesion to the substratum.

Blotting, Western↗
PubMed1996

Traumatized rat striatum produces neurite-promoting and neurotrophic activities in vitro.

We have previously reported that ciliary neurotrophic factor (CNTF) mRNA is upregulated in the rat striatum following trauma and that its peak is coincident with a peak in the number of GFAP-positive astrocytes. CNTF, or other neurotrophic factors present in the traumatized striatum, may be involved in the dopaminergic fiber sprouting seen following cavitation or graft implantation in animal models of Parkinson's disease. This study was undertaken in order to further characterize the neurotrophic activity present following trauma through the use of bioassays. Adult rats underwent stereotaxic biopsy of the right striatum, and gelatin sponge [gelfoam (GF)] was placed in the resultant cavity. GF was collected from 1 to 30 days following trauma and homogenized. GF extracts (with equal protein concentrations) were assayed using dorsal root ganglion (DRG) explants, dissociated ciliary ganglia (CG), and human dopaminergic neuroblastoma cell (SH-SY5Y) cultures. The GF extracts had significant neurite-promoting activity (NPA) for DRG, CG, and SH-SY5Y cells, with the maximum effect seen 7 days after trauma. NPA was not blocked by anti-nerve growth factor (NGF) Ab, but anti-brain-derived neurotrophic factor (BDNF) Ab significantly blocked the activity for DRG. The GF extracts protected the SH-SY5Y cells from the neurotoxins 6-OHDA and MPP+, as did NGF and BDNF. This neuroprotective effect of GF was not blocked by anti-NGF Ab. This study suggests that the neurotrophic activity in GF extracts has CNTF-like and BDNF-like components as well as another, undefined component.

Animals↗
PubMed1996

Interleukin-15 mRNA is expressed by human keratinocytes Langerhans cells, and blood-derived dendritic cells and is downregulated by ultraviolet B radiation.

Interleukin (IL)-15 is a recently described cytokine that shares many functional activities with IL-2; however, unlike IL-2, IL-15 is produced by monocytes/macrophages, and not by lymphocytes. In this report, we assessed IL-15 mRNA expression by freshly isolated human epidermal cells, as well as by negatively selected keratinocytes and positively selected Langerhans cells, utilizing reverse transcription and polymerase chain reaction. In addition, cultured keratinocytes, immortalized keratinocytes (HaCaT cells), and dendritic cells expanded from adult peripheral blood in the presence of granulocyte/macrophage-colony stimulating factor and IL-4 were examined for IL-15 transcripts. Using cultured keratinocytes, we also studied the regulation of IL-15 mRNA expression by ultraviolet B radiation in vitro. Freshly isolated keratinocytes, HaCaT cells, and cultured keratinocytes all constitutively expressed IL-15 mRNA, and IL-15 expression was downregulated by ultraviolet B radiation in cultured keratinocytes in a time- and dose-dependent manner. In addition, IL-15 transcripts were constitutively expressed by freshly isolated Langerhans cells. IL-15 produced by keratinocytes, Langerhans cells, and other tissue-specific dendritic cells may be important in attracting and activating antigen-specific Th1 T cells. Furthermore, ultraviolet B-induced downregulation of keratinocyte IL-15 production may contribute to the relative state of immunosuppression induced by sun exposure.

Adult↗