Biomedical subjects

H Ichikawa

Publications and source records attributed to H Ichikawa.

At least 253 records · Page 14Linked to original sources

PubMed1995

YAC analysis and minimal tiling path construction for chromosome 21q.

We have undertaken a detailed analysis of several hundred YACs from widely available YAC libraries which map to human chromosome 21 with the goal of improving the physical map of chromosome 21 and determining the feasibility of producing a minimal tiling path of well characterized, stable, non-chimeric YACs spanning the long arm of the chromosome (21q). We report information on over 500 YACs known to contain STS from 21q including information on size, stability, chimerism, marker content, and NotI restriction sites. YACs derive from the CEPH and St. Louis YAC libraries, and STSs include the set of 198 markers originally used do assemble a YAC contig of 21q, as well as additional anonymous probes and gene markers. This information has assisted in refinements of STS order, has defined a region of general instability in 2lq22.3, has identified an increased number of NotI restriction sites, and has defined cryptic gaps, particularly in 2lq2l, for which few or no markers are available. These results have allowed us to develop and assess a minimal tiling path of overlapping YACs consisting of 59 YACs (and two PI clones), largely non chimeric, stable, and of verified STS content. They total 30 mb of non-overlapping DNA, and contain all chromosome 21 specific STSs originally used to define the 810 YAC 21q YAC contig. When integrated with the analysis of a somatic cell hybrid mapping panel of chromosome 21 reported in the accompanying manuscript, a greatly enhanced understanding of the physical map of chromosome 21 is obtained.

Chromosome Mapping↗

PubMed1995

Extent of aortopulmonary collateral blood flow as a risk factor for Fontan operations.

Between November 1987 and January 1990, 33 patients (tricuspid atresia, 9 patients; mitral atresia, 3; single ventricle, 15; others, 6) underwent Fontan operations. The rate of blood flow returning to the heart during aortic cross-clamping was measured as an indication of the extent of development of aortopulmonary collateral arteries. Percent cardiac return (calculated by dividing the blood flow rate returning to the heart by the cardiopulmonary bypass blood flow rate and expressing the value as a percentage), were 1% to 9%, 7 patients; 10% to 19%, 11; 20% to 29%, 9; 30% to 39%, 4; 40% to 49%, 1; and 50% to 59%, 1 patient. Percent cardiac return showed a significant correlation with postoperative mean systemic venous pressure (r = 0.6, p < 0.01). In those patients in whom percent cardiac return was more than 33%, the mean systemic venous pressure after operation was high (more than 17 mm Hg), and none of these patients survived. To predict percent cardiac return preoperatively, the conventional indices of systemic ventricular volume, pulmonary artery area index, arterial blood oxygen saturation, pulmonary blood flow index, and pulmonary vascular resistance were analyzed. None of these showed significant correlation with percent cardiac return. However, all the patients who had a high percent cardiac return (more than 30%) also had both high arterial blood oxygen saturation (more than 75% in room air) and small pulmonary artery area index (less than 55%). In addition, the age at operation showed good correlation (r = 0.6, p < 0.01) to percent cardiac return.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1995

Inhibition of Na+/H+ exchanger attenuates neutrophil-mediated reperfusion injury.

BACKGROUND: The effect of Na+/H+ exchange inhibition in neutrophil-induced reperfusion injury was investigated using a new amiloride analogue, 5-methyl-N-isobutyl amiloride (MIA). METHODS: Rat neutrophils were separated using Percoll gradient. Luminol chemiluminescence intensity of isolated neutrophils was depressed by MIA in a dose-dependent manner. RESULTS: The effect of MIA on neutrophil-induced reperfusion injury was evaluated in Langendorff-perfused rat hearts subjected to 30 minutes of normothermic ischemia. Postischemic left ventricular developed pressure recovery was depressed by the reperfusion with neutrophils (60% +/- 7% to 33% +/- 26%) and was reverted by MIA pretreatment (86% +/- 17%, p < 0.05). MIA also improved percent recovery of coronary flow (51% +/- 2% to 70% +/- 13%), reduced creatine kinase (0.28 +/- 0.1 to 0.085 +/- 0.03 IU.L-1.g-1 dry wt), and lactate dehydrogenase leakage (10.6 +/- 3.8 to 5.16 +/- 1.3 IU.L-1.g-1 dry wt) significantly. The incidence of reperfusion-induced ventricular fibrillation also was reduced by MIA. CONCLUSIONS: The inhibition of Na+/H+ exchange shows a protective effect against neutrophil-induced reperfusion injury possibly by inhibiting the activation of neutrophils.

Amiloride↗

PubMed1995

Excretory/secretory antigens of adult Paragonimus ohirai recognized by a monoclonal antibody.

An IgM monoclonal antibody (mAb) that reacted with the gut epithelium and luminal contents of adult Paragonimus ohirai was prepared from a mouse immunized with the excretory/secretory (ES) products of the parasite. The mAb reacted with the same sites not only of immature worms and newly excysted juveniles of P. ohirai, but also of adult worms of other Paragonimus species, such as P. westermani and P. miyazakii. The mAb did not react with adult antigens prepared from any other helminth parasites. Thus, the mAb is a genus-specific antibody against the gut-associated antigen. Immunoblotting revealed that two antigens with molecular masses (M(r)s) of 27 and 29 kDa were present in the ES products of adult P. ohirai, whereas four antigens with M(r) 27, 29, 36, and 38 kDa were detected i adult worm extract. Partially purified fractions containing acidic and neutral cysteine proteinases have 27 and 29 kDa protein molecules reactive with the mAb. The possibilities that the 36 and 38 kDa antigens may be precursors of these proteinases are discussed.

Animals↗

PubMed1995

Adjuvant-induced persistent photosensitivity models in guinea pigs. I. Induction of persistent photosensitivity.

Induction of persistent photosensitivity in guinea pigs was carried out in an attempt to induce a model suitable to clarify the mechanism of human persistent light reactors. Guinea pigs were treated with intradermal injection of adjuvant which consisted of desiccated Mycobacteria followed by topical application of hapten solution and irradiation with UVA. Unequivocal skin reactions were subsequently elicited with UVA exposure in the absence of hapten application. This enhanced UVA reactivity persisted and could be elicited for more than 2 years. In these guinea pigs, remarkably increased sensitivity to UVB was also observed. These animals appear quite similar to persistent light reactors among humans. Muramyl dipeptide used in place of Mycobacteria was also found to be effective in inducing photosensitivity to UVA. There were great differences of reactivity noted among different strains of guinea pig, suggesting that persistent photosensitivity is influenced by genetic background. Enhanced UV sensitivity was induced without hapten application, only with injections of adjuvant and UVA irradiation in the immunization procedure. These results suggest that this model will be useful to study chronic actinic dermatitis.

Acetylmuramyl-Alanyl-Isoglutamine↗

PubMed1995

Adjuvant-induced persistent photosensitivity models in guinea pigs. II. Characterization of immunological mechanisms.

The immunological characteristics of our adjuvant-induced persistent photosensitivity (AIPP) guinea pig model were examined. The sensitivity to long-wavelength ultraviolet light (UVA) was transferred with peritoneal exudate cells. Proliferative response was observed in peritoneal exudate cells and lymph node cells concomitantly cultured in the presence of sera that had previously been irradiated with UVA. Cervical lymph nodes of AIPP animals were found to be hypertrophic, and the ratio of major histocompatibility complex (MHC) class II positive cells was increased as compared to that of intact guinea pigs. These results suggest that persistent photosensitivity elicited with UVA is based on cellular autoimmunity. Thus, the AIPP guinea pig model should be useful to study the mechanism of persistent photosensitivity disease in humans.

Adjuvants, Immunologic↗

PubMed1995

Fisher syndrome after Campylobacter jejuni enteritis: human leukocyte antigen and the bacterial serotype.

We describe two children who had Fisher syndrome subsequent to Campylobacter jejuni enteritis. The C. jejuni isolates from both patients, who lived in different areas, belonged to PEN 2: LIO 4. One patient had the following human leukocyte antigens (HLAs): HLA-A24, 33; B44, 52; DQ1; and DR2, 6 antigens. Another had the HLA-A24, 33; B44, 54; Cw1; DQ1, 4; and DR4, 6. An effort should be made to isolate C. jejuni from patients with Fisher syndrome and to perform HLA typing so that the pathogenesis of this syndrome can be clarified.

Adolescent↗

PubMed1995

Na+/Ca2+ exchange current density in cardiac myocytes from rabbits and guinea pigs during postnatal development.

It has been proposed that the activity of the cardiac sarcolemmal Na+/Ca2+ exchanger may be greatest in developing animals before the sarcoplasmic reticulum (SR) reaches functional maturity. Experiments were performed in rabbits, which have a sparse SR at birth, and in newborn guinea pigs, which exhibit a more extensive SR. Whole cell voltage clamp techniques were used to characterize the Ni(2+)-sensitive Na+/Ca2+ exchange current in single freshly isolated cardiac myocytes. Na+/Ca2+ exchange current was measured from a holding potential of -40 mV by using a slow-ramp voltage protocol (-120 to +60 mV, 0.09 V/s) in the presence of Ba2+, Cs+, tetraethylammonia, D-600, and ouabain to block Ca2+, Na+, and K+ currents. Experiments in developing rabbits (1-22 days old) demonstrated that Na+/Ca2+ exchange current density was greatest at 1-4 days and declined rapidly over the first 3 wk of age. In contrast, Na+/Ca2+ exchange current density in newborn guinea pig myocytes did not differ from that recorded in adults. These results confirm that Na+/Ca2+ exchange is functional at birth in both rabbits and guinea pigs. The species-related difference in the ontogeny of Na+/Ca2+ exchange is consistent with the concept that Na+/Ca2+ exchange assumes a relatively greater role in newborn animals with a sparse SR.

Animals↗

PubMed1995

Evaluation of influential factors of cognitive impairments in idiopathic Parkinson's disease.

Using multivariate analysis, we investigated the influence on cognitive functions of aging, brain atrophy, incidental cerebral hyperintensities (CHs), medication, and severity, duration and the initial symptoms of the disease in 53 patients with idiopathic Parkinson's disease (PD). We semiquantitatively assessed the degree of brain atrophy and CHs based on previously established methods. Cognitive functions were significantly and diffusely impaired in PD when compared with controls who were matched for age as well as for the degree and location of CHs. Patients with PD, however, had larger ventricles. Prefrontal dysfunctions were associated with a variety of predictors such as CHs, brain atrophy, severity of PD and medication whereas dorsolateral frontal functions were related simply to age and CHs in the periventricular region. Posterior brain functions had association with severity of illness, ventricular dilatation and total CH score. Clinically observed cognitive impairments in PD may consist of cognitive defects intrinsic to the disease which are variously modified by these factors. It is essential to consider all these predictors simultaneously in any discussion of cognitive functions in PD.

Aged↗

PubMed1995

[Studies on antiulcer agents. III. Synthesis and antiulcer activity of phenylpropanol derivatives].

It was found that (+/-)ethyl 2-[2-(3-hydroxypropyl)-4-oxocyclohexylidene]-propionate (1), (+/-)ethyl 2-[2-(3-hydroxypropyl)-4,5-dimethoxyphenyl]propionate (2) and (+/-)3-[2-(3-hydroxypropyl)-4,5-dimethoxyphenyl]-2-butanone (3) had excellent antiulcer activities. In order to study structure-activity relationships, (+/-)2-[(3-hydroxypropyl)phenyl]cyclopentanone derivatives (4, 5) and (+/-)2-[(3-hydroxypropyl)phenyl]cyclopentanol derivatives (6, 7) were synthesized and tested for antiulcer activities. As a result, (+/-)2-[2-(3-hydroxypropyl)-4-methoxy-5-(2- piperidinoethoxy)phenyl]cyclopentanone (5k) exhibited potent antiulcer activities.

1-Propanol↗

PubMed1995

[Studies on antiulcer agents. IV. Synthesis and antiulcer activity of phenylpropanol derivatives].

It was found that (+/-)ethyl 2-[2-(3-hydroxypropyl)-4-oxocyclohexylidene-propionate (1), (+/-)ethyl 2-[2-(3-hydroxypropyl)-4,5-dimethoxyphenyl]propionate (2), (+/-)3-[2-(3-hydroxypropyl)-4,5-dimethoxyphenyl]-2-butanone (3) and (+/-)2-[2-(3-hydroxypropyl)-4-methoxy-5-(2- piperidinoethoxy)phenyl]cyclopentanone (4) had potent antiulcer activities. In order to study structure-activity relationships, (+/-)3-[(3-hydroxypropyl)phenoxy]-2-butanone derivatives (5, 6) were synthesized and tested for antiulcer activities. Among them, (+/-)3-[2-(3-hydroxypropyl)-4-methoxy-5-[3-(4- methylpiperidino)propoxy]phenoxy]-2-butanone.3/2 oxalate (6k) was selected as a preferred antiulcer agent.

1-Propanol↗

PubMed1995

A conditional negative selection for Arabidopsis expressing a bacterial cytosine deaminase gene.

The enzyme activity for cytosine deaminase, which converts cytosine to uracil in bacterial, is usually undetected in higher plants and animals. The enzyme also catalyzes conversion of non-toxic 5-fluorocytosine (5-FC) to 5- fluorouracil (5-FU), a toxic compound for plant growth. The gene encoding cytosine deaminase (codA) from Escherichia coli was fused to cauliflower mosaic virus (CaMV) 35S promoter (P35S), and cloned into a binary vector pLABR101. The resulting plasmid pLABR102 contained two marker genes for plants: a positive marker gene, bialaphos resistance (bar) gene driven by the promoter from nopaline synthase gene (Pnos) and a negative one, P35S-codA. The binary vector pLABR102 was transformed into Arabidopsis thaliana via Agrobacterium-mediated transformation. In transgenic progenies (T3) of the second (T2) generation heterozygous for a single T-DNA insertion, a 3:1 segregation ratio was observed on both bialaphos (resistance to sensitive) and 5-FC (sensitive to unaffected). From T2 plants homozygous for the T-DNA insert, on the other hand, no segregation was detected: all the T3 seedlings were resistant to bialaphos and sensitive to 5-FC. PCR and Northern analyses showed that the 5-FC sensitivity in transgenic descendants was caused by the integration and expression of the chimeric codA gene in the Arabidopsis genome. The results indicated that cytosine deaminase from E. coli is functional and useful for negative selection in Arabidopsis, and that sensitivity to 5-FC as well as the positive bialaphos resistance are dominant traits in Arabidopsis.

Acetyltransferases↗

PubMed1995

Effect of tea polyphenols on fecal flora and fecal metabolic products of pigs.

The effects of tea polyphenols on fecal flora and fecal metabolic activities were studied in eight 30-day-old pigs fed a basal diet (control) or the diet supplemented with 0.2% of tea polyphenols for 2 weeks. During tea polyphenol administration compared to before administration, the levels of lactobacilli were increased significantly (P < 0.05 and P < 0.01 on days 7 and 14 of administration, respectively), whereas the levels of total bacteria (P < 0.01) and bacteroidaceae (P < 0.01 and P < 0.001 on days 7 and 14 of administration, respectively) were decreased significantly. The detection rate of lecithinase positive clostridia including Clostridium perfrigens showed a tendency to decrease during administration. No detectable change occurred in the levels of other organisms throughout the experimental period. Fecal concentrations of ammonia were decreased significantly (P < 0.05 and P < 0.01 on days 7 and 14 of administration, respectively). Fecal phenol (P < 0.001), p-cresol (P < 0.05), and skatol (P < 0.01) were reduced significantly on day 14 of administration compared to before administration. The amounts of fecal short chain fatty acids, acetic acid (P < 0.05) and lactic acid (P < 0.05) were increased significantly on day 14 of administration. The pH values were decreased slightly during administration. The odour of the feces was reduced remarkably during tea polyphenol administration.

Animals↗

PubMed1995

Intention tremor and olivary enlargement: clinico-radiological study.

This study describes two patients who presented with intention tremor (IT) concomitant with olivary enlargement (OE), and discusses the relationship between these phenomena. Both patients had a vascular lesion in the brain stem, which subsequently caused IT and OE ipsilateral or contralateral to the site of the lesion, depending on the structures effected by the lesion. The results of our study suggest that damage involving the superior cerebellar tract, and central tegmental tract, or both, may result in IT and OE. However, IT and OE appear to have little physiological association, unlike the relation between OE and palatal myoclonus.

Humans↗

PubMed1995

Microscopic anatomy of the equine skin with special reference to the dermis.

We have observed and re-evaluated the histology of the skin of the horse, using samples from four Thoroughbreds. The skin was composed of the usual three components: epidermis, dermis and subcutis. In particular, the dermis was found to have three fibrous components: a papillary layer, a reticular layer and a cordovan-leather tissue layer. The cordovan-leather tissue layer was subdivided into a superficial main layer and a deeper accessory layer. The superficial main layer was thick, and present in all of the skin samples. The deeper accessory layer was found in the dorsal and dorso-lateral parts of the neck and trunk and in the extremities. Hair bulbs and sudoriferous glands did not extend into the cordovan-leather tissue layer and subcutis.

Animals↗

PubMed1995

[Mirror movements observed in patients skilled in playing the piano--symptomatological study].

We investigated mirror movements observed in two patients skilled in playing the piano and compared these symptoms with those reported in patients associated with frontal lobe, corpus callosum or cervical cord lesion. We found the following common features in our two patients: 1) mirror movements were observed during skilled finger movements such as playing the piano, 2) these were observed in distal parts of the bilateral upper extremities, 3) contralateral imitative associated movements were seen concomitantly, 4) frontal lobe symptoms and callosal disconnection syndrome were not seen, 5) both patients recalled having mirror movements in their infancy, and one had family history. These characteristics of mirror movements in our patients were similar to those in patients associated with cervical cord lesion, but were different from those in patients associated with frontal lobe or corpus callosum lesion. It is suggested that abnormal pathways in the pyramidal tract or cervical cord lesion elicited mirror movements in our patients.

Adult↗

PubMed1995

[Fisher's syndrome following Campylobacter jejuni enteritis--a case report and review of the literature].

A 13-year-old boy presented with ophthalmoplegia, cerebella ataxia and areflexia subsequent to watery diarrhea and pyrexia. Campylobacter jejuni (PEN 2: LIO 4) was isolated from the stools. The patient had a high titer of IgG anti-GQ1b IgG antibody titers which decreased during the clinical course. Although C. jejuni has recently been recognized as the most common microorganism causing infection preceding Guillain-Barré syndrome, only six patients with Fisher's syndrome after this bacterial infection have been reported. This is the first report of a patient with Fisher's syndrome in whom C. jejuni was identified as a causative organism in Japan.

Adolescent↗

PubMed1995

[Diltiazem abolishes the effect of ryanodine in St. Thomas' Hospital cardioplegic solution on the post-ischemic functional recovery].

Calcium-induced calcium release (CICR) from sarcoplasmic reticulum (SR) may contribute to calcium depletion of SR during the infusion of cardioplegic solution, which may protect the intracellular calcium overload observed during myocardial reperfusion. We have, therefore, investigated (1) the ability of ryanodine-containing cardioplegic solution to enhance myocardial protection and (2) the influence of diltiazem, L-type calcium channel blocker, on the ryanodine-enhanced cardioprotective effect in the isolated working rat heart. Hearts (n = 6-8/group) from male Wistar rats were aerobically (37 degrees C) perfused (20 min) with bicarbonate buffer (Ca2+ = 2.4 mM). This was followed by a 3 min infusion of St. Thomas' Hospital cardioplegic solution containing (1) 0 nmol/L of ryanodine or (2) 1.75 nmol/L of ryanodine combined with various concentrations of diltiazem (0, 0.13, 0.25 and 0.50 mumol/L). Hearts were then subjected to 40 min of normothermic (37 degrees C) global ischemia and 35 min of reperfusion (15 min Langendorff, 20 min working). (1) The recovery of aortic flow (%AF) was 52.2 +/- 3.5% in the ryanodine-free group. (2) %AF was 72.0 +/- 1.4%, 50.0 +/- 2.6*, 61.7 +/- 3.2* and 58.3 +/- 2.8*% in the 0, 0.13, 0.25 and 0.50 mumol/L diltiazem groups, respectively (*p < 0.05 vs the 0 mumol/L diltiazem group). Creatine kinase (CK) leakage during Langendorff reperfusion was less in the 0 mumol/L diltizaem (plus 1.75 nmol/L ryanodine) group than the ryanodine-free group.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗