Biomedical subjects

H Yamaguchi

Publications and source records attributed to H Yamaguchi.

At least 649 records · Page 36Linked to original sources

PubMed1996

[Augmented ability of spleen cells to produce interferons and prevention from lethal infection of herpes simplex virus in mice orally treated with Enterococcus faecalis preparation, FK-23].

Effects of the oral or intraperitoneal administration of an Enterococcus preparation, FK-23, to mice on the interferon (IFN) production by their spleen cells and on the host defense against the infection with herpes simplex virus (HSV)-1 were examined. Spleen cells were obtained from the mice intraperitoneally treated with cyclophosphamide (CY) and subsequently orally administered FK-23 preparation, and then cultured with phytohemagglutinin-P or bacterial lipopolysaccharide in vitro. They produced higher titers IFN than those obtained from control mice which were not treated with the FK-23 preparation. The IFN activity was neutralized mainly by antiIFN-beta antibody. Correspondingly, oral (5 mg/mouse) or intraperitoneal (1 mg/mouse) administration of the FK-23 preparation protected some of the CY-pretreated mice from death by HSV-1 infection.

Administration, Oral↗

PubMed1996

A case of swallowing-induced atrioventricular block after myocardial infarction.

We report a patient with transient atrioventricular (AV) block induced by swallowing. He complained of recurrent dizziness during meals and had suffered from inferior myocardial infarction 1 year before the onset of these symptoms. Radiologic examination showed no apparent esophageal abnormalities. Swallowing a piece of solid food or hot liquid repeatedly provoked advanced AV block. Administration of intravenous atropine sulfate prevented AV block. An electrophysiologic study revealed that this swallowing-induced AV block was an intranodal (A-H) block. We did not implant a cardiac pacemaker because his symptoms were not very serious and could be prevented by eating carefully. The patient has been symptom-free for the past 12 months. The previous myocardial infarction may be related to the appearance of this vagal-related AV block.

Deglutition↗

PubMed1996

Calcitonin gene-related peptide inhibits human platelet aggregation.

Calcitonin gene-related peptide (CGRP) is a potent vasodilator in humans. CGRP receptors have also been found in various tissues other than blood vessels, such as the central nervous system, kidney, and heart. However, little is known about the effects of CGRP on human platelets. We investigated the effect of CGRP (human alpha type) on platelet aggregation in 21 healthy subjects (9 men and 12 women, mean age 54.6 years). CGRP inhibited platelet aggregation in vitro in 19 of the subjects (90.5%) in a dose-dependent manner with 50% inhibitory doses of 1.6 mumol/L and 1.1 mumol/L for aggregation induced by epinephrine and collagen, respectively. 125I-labeled CGRP bound specifically to intact platelets. The dissociation constant (Kd) was 61.9 +/- 17.7 pmol and the maximum number of binding sites (Bmax) was 5.4 +/- 3.9 pmol/10(9) platelets. The CGRP analogue (8-37)CGRP, but not calcitonin, inhibited the binding of 125I-CGRP to platelets. CGRP (5 mumol/L), but not (8-37)CGRP or calcitonin, increased the platelet cyclic AMP (cAMP) concentration by 31.7 +/- 3.6%. Thus, CGRP inhibits platelet aggregation via a specific receptor and by increasing the platelet cAMP concentration. CGRP may play a role in the modulation of platelet function in humans.

Adult↗

PubMed1996

Molecular dynamics (MD) simulation of DNA dodecamer with 5-hydroxy-6-cytosinyl radical.

Molecular dynamics (MD) simulation of DNA dodecamer d (CGCGAATTC*GCG)2 with a primary radiation damage represented by 5-hydroxy-6-cytosinyl radical (C*) in position 9 was performed with AMBER 4.0 force field with periodic boundary conditions for the solvent. The temperature, potential energy of the system, energetic contributions from groups and RMS deviation from original positions were examined throughout the course of the simulation up to 140 ps. The stabilized structure (after 100 ps) was distorted and bent near the damaged site, which is similar to that observed in the MD of DNA with thymine glycol (Miaskiewicz, K. et al (1994) Radiat. Protection Dosimetry, 52, 149-153). The results suggest that a small and local damage in DNA may cause a large and global conformational change in DNA. Water molecules form two layers at distance 2.5 A and 5.5 A around the DNA. The MD simulation is a new approach to study radiation damages in molecular level.

Base Sequence↗

PubMed1996

Enhanced cholinergic activity in the medulla oblongata of DOCA-salt hypertensive and renal hypertensive rats.

We previously demonstrated that cholinergic activity in the medulla oblongata is enhanced in adult spontaneously hypertensive rats (SHR), a genetically hypertensive rat model. In this study, we examined possible alterations of medulla oblongata cholinergic mechanisms in nongenetic forms of hypertension, using deoxycorticosterone acetate (DOCA)-salt hypertensive and renal hypertensive rats. At a fully developed stage of hypertension in DOCA-salt hypertensive and renal hypertensive rats, choline acetyl-transferase (CAT) activity in the rostro-ventral medulla oblongata was enhanced, whereas there was no change in the activity of CAT in other parts of the medulla oblongata. There was no alteration of the medulla CAT activity in prehypertensive SHR or at an early stage of renal hypertension. Increases in blood pressure and plasma catecholamine levels induced by physostigmine (0.5 mg/kg, i.p.) were enhanced in DOCA-salt hypertensive and renal hypertensive rats. These findings suggest that cholinergic activities in the medulla oblongata are enhanced and that such activities are involved in enhancement of the sympathetic nervous system in non-genetically hypertensive rats. It seems unlikely that the altered cholinergic activity in the rostral ventrolateral medulla of adult SHR occurs genetically.

Animals↗

PubMed1996

Optimal dose of enterococcal preparation (FK-23) supplemented perorally for stimulation of leukocyte reconstitution in dogs treated with cyclophosphamide.

Optimal doses of orally supplemented heat-killed Enterococcus faecalis FK-23 preparation (FK-23) were evaluated in dogs treated with cyclophosphamide (CY). Leukocyte reconstitution was stimulated by the supplement of 100 mg/kg of FK-23 through an induction of neutrophilia, and the treatment of 10 mg/kg of FK-23 induced mild neutrophilia in dogs tested. However, the reconstitution was not stimulated by the treatment of 200 or 400 mg/kg of the drug. Although the effects of FK-23 appeared to be milder than those of recombinant human granulocyte colony stimulating factor (rhG-CSF), there was no significant difference in the leukocyte reconstitution between the two substances. An appropriate dose of FK-23 is 100 mg/kg for augmentation of leukocyte reconstituting capacity in dogs treated with CY.

Adjuvants, Immunologic↗

PubMed1996

Idiopathic ventricular fibrillation initiated by a short-coupled ventricular premature beat.

We report the case of a 38-year-old man who had idiopathic ventricular fibrillation (VF) which initiated by abnormally short-coupled ventricular premature beats. VF was successfully prevented by the combination of pilsicainide, propranolol, and verapamil. In particular, the effects of pilsicainide are assumed to exert an important effect in controlling this arrhythmia. Class Ic drugs may be effective for preventing VF initiated by short-coupled VPBs.

Adult↗

PubMed1996

Effectiveness of probucol in preventing restenosis after percutaneous transluminal coronary angioplasty.

Lipid lowering therapies were employed to prevent restenosis following elective percutaneous transluminal coronary angioplasty (PTCA). The effect of probucol was compared to that of Pravastatin in 141 coronary atherosclerosis patients. Probucol (750 mg/day) was administered for at least 30 days prior to PTCA (34 patients, group P-1) or less than 14 days prior to PTCA (27 patients, group P-2). Pravastatin (10 mg/day) was administered for at least 30 days prior to PTCA (38 patients, group V-1) or less than 14 days prior to PTCA (42 patients, group V-2). In group P-1, the patient restenosis rate was 17.6% and lesion restenosis rate was 14%. These rates were significantly lower than those of group V-1, which were 44.7% and 40.4% respectively (p < 0.05). The respective values were 48.1% and 51.8% in group P-2 (p < 0.05, vs group P-1) and 35.7% and 34% (p < 0.05, vs group P-1) in group V-2. Probucol seems to work, not only by lowering cholesterol but also by its antioxidative properties when administered for a sufficient period prior to PTCA.

Angioplasty, Balloon, Coronary↗

PubMed1996

Vitamin A is involved in estrogen-induced cell proliferation but not in cytodifferentiation of the chicken oviduct.

We examined vitamin A-deficient chicks to determine whether vitamin A affects the estrogen-induced development of the chick oviduct. When oviduct development was stimulated for 5 days with the synthetic estrogen, diethylstilbestrol, the wet weight of the oviduct in vitamin A-deficient chicks was only half that in control chicks. The DNA content in this tissue showed that the decreased oviduct weight in the vitamin A-deficient chicks was caused by the decreased proliferation of oviduct cells. However, the estrogen-induced expression of the ovalbumin gene was not affected by the vitamin A deficiency, suggesting that estrogen-induced cytodifferentiation is not affected by vitamin A. To clarify the vitamin A action on estrogen-induced development in the oviduct, transcripts of nuclear estrogen receptor (ER) and all-trans-retinoic acid (RAR alpha, beta and gamma) receptors, which exert the effects of estrogen and vitamin A, were measured. The ER, RAR alpha and RAR beta genes, but not that of RAR gamma, were expressed during oviduct development, indicating that estrogen and vitamin A may control the expression of target genes through their cognate receptors. Thus, we have shown that vitamin A is involved in estrogen-induced cell proliferation but not in cytodifferentiation of the chicken oviduct.

Animals↗

PubMed1996

Tissue distribution and plasma concentration of human guanylin.

Guanylin, a peptide homologue of the bacterial heat-stable enterotoxins, is an endogenous activator of guanylate cyclase C (GC-C). We determined the tissue content and plasma concentration of human guanylin, and its cellular source in the intestine. Human guanylin is distributed widely from the duodenum to the rectum, the highest content being in the ileum and proximal colon. The plasma concentration of immunoreactive guanylin in the normal individuals tested was 30.3 +/- 3.7 fmol/ml (mean +/- SE) and that in patients with chronic renal failure was elevated with increasing serum creatinine concentration. Guanylin immunoreactivity was detected in the villus epithelial cells in the small intestine and these guanylin-containing cells were increased in number along the cephalocaudal axis of the gut. Guanylin was also present in Paneth cells in the small intestine and superficial epithelial cells in the large intestine. Guanylin mRNA was detected in the intestine by the reverse transcription-polymerase chain reaction. Guanylin may have paracrine action on neighboring enterocytes, activating intestinal guanylate cyclase and thereby regulating intestinal fluid as well as electrolyte transport through the second messenger, cyclic GMP.

Adolescent↗

PubMed1996

Marked arteriosclerosis of the descending aorta in a teenager with interruption of the aorta.

Marked arteriosclerosis localized to the descending thoracic and abdominal aorta was observed in a 19-year-old girl with interruption of the aorta (type A) and a ventricular septal defect. She died from rupture of saccular aneurysm of the pulmonary trunk. The descending thoracic and abdominal aorta showed marked thrombogenic, lamellar thickening of the intima. In contrast, no significant arteriosclerosis was detected in the ascending aorta. Several factors including diffuse sludging of blood, mural thrombosis and hemodynamic changes, in close association with polycythemia, are hypothesized to be causative factors in the development of this lesion.

Adult↗

PubMed1996

Multiple endocrine neoplasia type 1 associated with malignant lymphoma and other complications.

A 49-year-old female with multiple endocrine neoplasia (MEN) type 1 associated with malignant lymphoma, lipoma, functioning adenomatous goiter, non-functioning adrenal tumor, polyneuropathy, postoperative primary hyperparathyroidism, and hepatitis B virus was a human T lymphotropic virus type 1 (HTLV-1) carrier. She underwent parathyroidectomy for primary hyperparathyroidism at age 44. At age 49, examinations of the enlarged para-aortic lymph nodes revealed diffuse small non-cleaved B cell lymphoma in stage II, and other various complications were also found. Multiple tumorigenetic factors were considered to be involved in the present case.

Adrenal Gland Neoplasms↗

PubMed1996

Protection of C3H/HE J mice from development of Candida albicans infection by oral administration of Juzen-taiho-to and its component, Ginseng radix: possible roles of macrophages in the host defense mechanisms.

Protective effect of a Japanese traditional herbal medicine, Juzen-taiho-to (TJ-48), which was recently reported to augment host-mediated antifungal actions, in Candida albicans-infected mice was further studied. TJ-48, given orally once daily for 5 consecutive days in a dose of 2 g/kg after intravenous infection of C. albicans, prolonged survival period of infected mice of a C3H/He J strain which is characteristic of functional deficiency of macrophages, but did not that of infected mice of a C3H/He N strain with normal macrophage function. Peritoneal macrophages obtained from C3H/He J mice showed a moderate inhibitory activity against Candida growth in vitro. The anti-Candida activity of the macrophages was augmented by the addition of TJ-48 or some component extracts of TJ-48 to the incubation medium. Among such active component extracts is an extract of Ginseng radix which was demonstrated to enhance the anti-Candida activity of macrophages in vitro and to prolong the survival time of C. albicans-infected C3H/He J mice without effect on C3H/He N mice. On the base of these findings, the mechanisms underlying the protective action of TJ-48 against systemic Candida infection was discussed in relation with its possible activity to activate the macrophage function.

Administration, Oral↗

PubMed1996

Antifungal antibiotic benanomicin A increases susceptibility of Candida albicans to phagocytosis by murine macrophages.

Benanomicin A is an antifungal antibiotic produced by Actinomadura spadix. In the present study, we investigated the effect of benanomicin A on the phagocytosis of Candida albicans by murine peritoneal macrophages and on the cell-surface hydrophobicity (CSH) of C. albicans. Although pretreatment of macrophages with benanomicin A had no effect on the phagocytosis, addition of benanomicin A to the culture of macrophages and Candida cells increased the susceptibility of Candida cells to the phagocytosis by the macrophages. Pretreatment of Candida cells with benanomicin A also increased the susceptibility of Candida cells to the phagocytosis. When Candida cells were mixed with benanomicin A, the antibiotic bound irreversibly to Candida cells. These data suggest the possibility that the increased susceptibility of Candida cells to the phagocytosis is mediated by the binding of benanomicin A to Candida cells. Examination of physicochemical property of Candida cell surface showed that the CSH of Candida cells significantly decreased by the treatment with benanomicin A. Thus, binding of benanomicin A to Candida cells may induce biochemical/physicochemical alternation of the surfaces, so that they become more susceptible to phagocytosis by murine macrophages. These properties of benanomicin A, along with its antifungal activity, seem to be beneficial in the treatment of fungal infections.

Animals↗

PubMed1996

YM-47522, a novel antifungal antibiotic produced by Bacillus sp. I. Taxonomy, fermentation, isolation and biological properties.

YM-47522, a novel antibiotic, was isolated from the culture broth of Bacillus sp. YL-03709B. The antibiotic was purified by centrifugal partition chromatography and ODS column chromatography. It exhibited potent in vitro antifungal activity especially against Rhodotorula acuta and Pichia angusta (MIC: 0.05 and 0.75 microgram/ml, respectively). It also showed moderate or weak antifungal activity against Candida albicans and Cryptococcus neoformans (MIC: 25 and 6.25 micrograms/ml, respectively), whereas it was inactive against filamentous fungi and bacteria.

Antifungal Agents↗

PubMed1996

Binding of benanomicin A to fungal cells in reference to its fungicidal action.

An antifungal antibiotic, benanomicin A, binds in the presence of Ca2+ to susceptible fungi and some bacteria, but not to antibiotic-resistant bacteria and mammalian cells. With the susceptible yeast Saccharomyces cerevisiae, benanomicin A binds similarly to whole cells and to protoplasts. Studies using benanomicin A and three structurally related derivatives suggested that a carboxylic acid in the D-alanine moiety and a sugar moiety in the benanomicin A molecule are essential for both binding and antifungal activities against growing S. cerevisiae. An amino substituent on the sugar moiety can be replaced with a hydroxyl group without the loss of activities. Benanomicin A binds to various yeast mannans which differ in glycosidic linkages. These results indicate that binding of benanomicin A to the mannan portion of fungal cells is essential for exertion of the antifungal activity.

Anthracyclines↗

PubMed1996

[Reconstruction procedure for full-thickness chest wall defects].

Reconstruction of full-thickness chest wall defects after the total layer resection of the chest wall has been performed on 6 cases. Five of 6 cases had local recurrent of breast carcinoma, one case had a recurrent liposarcoma in the chest wall. The reconstruction procedure of skeletal chest wall used to double soft Marlex mesh. The soft tissue layer of the chest wall was reconstructed with myocutaneous flaps in five cases (four cases using latissimus dorsi, one case using rectus abdominis), with omental pedicle graft and free skin flap in one case. Minor wound complications occurred in 2 in the 6 cases, one case had myocutaneous flap using rectus abdominis, the other case using omental pedicle flap, but any postoperative complications including respiratory insufficiency was not seen with myocutaneous flap using latissimus dorsi. The latissimus dorsi myocutaneous flap was most suitable to cover the soft tissue layer of the chest. We confirmed that Marlex mesh and latissimus dorsi myocutaneous flap were able to reconstructed for large defects of full-thickness chest wall involving the sternum, there were best approach to reconstruction full-thickness chest wall defects after total layer chest wall resection.

Aged↗

PubMed1996

Purification and characterization of Lewy bodies from the brains of patients with diffuse Lewy body disease.

Lewy bodies (LBs) are the pathological hallmarks of degenerating neurons in the brains of patients with Parkinson's disease and diffuse Lewy body disease. We developed a novel purification procedure for LBs using sucrose density separation followed by fluorescence-activated particle sorting, and we raised > 15 monoclonal antibodies to LBs purified from diffuse Lewy body disease brains. The monoclonal antibody that stained the largest number of LBs most intensely did not recognize ubiquitin in free or monoubiquitinated forms nor the ubiquitin conjugating enzymes, but it did react with polyubiquitin chains as well as with high molecular weight polyubiquitinated LB-derived proteins. Thus, these results suggest that LBs contain polyubiquitin chains. Although polyubiquitination of LB proteins may trigger ubiquitin-proteasome proteolytic pathways, the incomplete activation of these pathways could play a mechanistic role in the formation of LBs in neurodegenerative diseases.

Aged↗