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Biomedical subjects

H Yoshida

Publications and source records attributed to H Yoshida.

At least 1,117 records · Page 62Linked to original sources
PubMed1995

Comparison of the effect of monopolar and bipolar cauterization on skeletonized, dissected internal thoracic arteries.

The internal thoracic artery is preferable to the saphenous vein for use as a conduit for coronary artery bypass. More extensive use is possible if this artery is mobilized in a skeletonized form to provide greater length. Internal thoracic arteries are usually mobilized with cauterization. This study compared the effectiveness and effects on neighboring areas of division of the branches of the canine internal thoracic artery with bipolar cauterization and monopolar cauterization. Branch closure was significantly more secure in the bipolar cauterization group, with bleeding in 25 (9%) of 279 branches of 15 internal thoracic arteries treated with monopolar cauterization, in contrast to bleeding in 4 (1.3%) of 306 branches in the 15 internal thoracic arteries treated with bipolar cauterization, which were paired with the group treated with monopolar cauterization. The group of internal thoracic arteries treated with monopolar cauterization had a significantly higher prevalence of leakage when luminal pressure was increased from 120 to 160 mm Hg. Scanning electron microscopy demonstrated partial loss of endothelial cells on the flow surface of internal thoracic arteries treated with bipolar cauterization, compared with almost complete loss of endothelial cells around the orificial areas after monopolar cauterization. Secondary bipolar cauterization treatment caused only slightly more damage than primary treatment, but secondary monopolar cauterization was much more severe and extensive than primary treatment. These data suggest that bipolar cauterization is preferable to monopolar cauterization for skeletonized dissection of the internal thoracic artery.

Animals↗
PubMed1995

Pathogenicity of bacteria using a simulated root canal system.

The purpose of this study was to investigate the reliability of an implantation test using Teflon-simulated root canals for evaluating the pathogenicity of root canal bacteria. Models including suspensions of lyophilized strains (Actinomyces israelii, Streptococcus faecalis, and Porphyromonas asaccharolyticus) were implanted in rat subcutaneous tissue for 1 wk, and histological changes were observed. Severe inflammation occurred around the models. Among them, P. asaccharolyticus induced the severest inflammatory response. Further study using P. asaccharolyticus was conducted to compare the implantation test's ability to evaluate pathogenicity with that of an injection test at 1, 2, or 4 wk. Tissue injected with a bacterial suspension showed no clear response through the experimental periods, whereas tissue around implantation sites showed a severe response at 1 wk. However, the inflammatory response subsided at later stages. Consequently, further improvement is needed to investigate pathogenicity for long periods.

Actinomyces↗
PubMed1995

Effect of differential shear stress on platelet aggregation, surface thrombosis, and endothelialization of bilateral carotid-femoral grafts in the dog.

PURPOSE: The purpose of this study was to determine the effects of increased shear stress on the aggregability of platelets as they traverse a long, small-caliber (6 mm) Dacron graft in the dog and on the surface thrombosis and endothelialization of such a graft. METHODS: Each of nine dogs received bilateral carotid-femoral artery grafts, approximately 75 cm long, for 3 months; one graft of each pair had a distal femoral arteriovenous fistula to produce a higher shear rate than the contralateral graft. Platelet aggregation scores were determined on blood withdrawn from the external jugular vein and from the proximal and distal ends of the grafts in each animal. Graft flow rates, which were used in the computation of shear stress, and luminal pressure gradients through grafts were measured during surgery and specimen retrieval. Specimens were studied with light microscopy after hematoxylin and eosin and immunocytochemical staining and by scanning electron and transmission electron microscopy to evaluate the nature, composition, and thickness of the flow surface lining, as well as the transmural healing. RESULTS: Two high-shear stress and two low-shear stress grafts occluded unilaterally; five dogs had bilaterally patent grafts, allowing comparative analyses. All subjects had low platelet aggregability with aspirin. Platelet aggregation scores taken from proximal and distal ends of the grafts were not significantly different. The high-shear stress grafts had significantly more endothelial-like cell coverage (p < 0.0371) than the low-shear stress grafts, less flow-surface thrombus (p < 0.0056), and a thinner surface lining (p < 0.0029), on both the neointima and pseudointima. CONCLUSIONS: In subjects with low platelet aggregation scores, long Dacron grafts do not elevate platelet aggregability of blood flowing through them. High-shear stress grafts have less flow surface thrombus, more endothelialization, and a thinner surface lining than do low-shear stress grafts.

Animals↗
PubMed1995

Effect of in-vivo supplementation with low-dose vitamin E on susceptibility of low-density lipoprotein and high-density lipoprotein to oxidative modification.

OBJECTIVES: We have examined the effects of in-vivo supplementation with low-dose vitamin E on the susceptibility of low-density lipoprotein (LDL) and high-density lipoprotein (HDL) to oxidative modification, and compared the oxidizability of HDL with that of LDL. METHODS: Normal humans (n = 8) ingested vitamin E (150 mg/day for 1 week, followed by 300 mg/day for 3 weeks) in divided doses with meals. The subjects did not use any medications or vitamins before being enrolled in this study. Fasting blood samples were drawn before and at the end of supplementation. LDL and HDL were separated by sequential ultracentrifugation and susceptability to copper-mediated oxidation was measured. RESULTS: After vitamin E supplementation, vitamin E content of LDL increased 1.9-fold and that of HDL increased 1.8-fold. Lag time before initiation of LDL oxidation lengthened significantly (+20%, p < 0.01), and the propagation rate of LDL decreased significantly (-10%, p < 0.05). The lag time of HDL oxidation did not change significantly, but the propagation rate of HDL oxidation decreased significantly (-24%, p < 0.001). The lag time of HDL oxidation was shorter than that of LDL. HDL contained the same or higher concentrations of vitamin E relative to lipid mass as LDL, but contained lower concentration of CoQ10 relative to lipid mass and fewer molecules of vitamin E and beta-carotene per particle than LDL. CONCLUSIONS: We conclude that in-vivo supplementation of low-dose vitamin E protects LDL against oxidative modification and decreases the propagation rate of HDL oxidation significantly. We suggest that supplementation with low-dose vitamin E would be beneficial for ameliorating atherosclerosis.

Adult↗
PubMed1995

The expression of placental-type glutathione S-transferase (GST-pi) in human cutaneous carcinoma in situ, that is, actinic keratosis and Bowen's disease, compared with normal human skin.

The expression of human placental type glutathione S-transferase (GST-pi) was investigated in human cutaneous carcinoma in situ, that is, actinic keratosis and Bowen's disease, and compared with that in normal skin, using Northern blot and immunohistochemical analysis. In Northern blot examination, the expression of GST-pi transcript was recognized in all instances. Carcinoma in situ showed significantly higher expressions of GST-pi than normal skin. In the immunohistochemical examination, nuclear staining of GST-pi was noticed in some dysplastic cells of carcinoma in situ, especially in Bowen's disease. In actinic keratosis, a framework appearance was noticed in the staining pattern at a lower magnification because the lower part of the cytoplasm of dysplastic cells lining the stratum basale was positive for GST-pi, and all cells of the stratum granulosum and more cells of the stratum spinosum showed stronger GST-pi positive reaction than normal skin. In Bowen's disease, GST-pi positive, dysplastic cells existed throughout the epidermis. Because GST-pi positive, dysplastic cells and GST-pi positive, normal looking squamous cells made the GST-pi positive cell nests throughout the epidermis, and GST-pi positive, dysplastic cells, and GST-pi negative, normal looking cells coexisted in the parabasal layer, they showed a sawtooth appearance in the staining pattern at a lower magnification. These findings suggest that GST-pi is involved in the process of carcinogenesis.

Adult↗
PubMed1995

Midkine (MK) expression in extraembryonic tissues, amniotic fluid, and cerebrospinal fluid during mouse embryogenesis.

Midkine (MK) and pleiotrophin (PTN) constitute a new family of heparin-binding growth factors. Extraembryonic membranes and the placenta of the mouse expressed MK mRNA at 11.5 days gestation. While the MK mRNA level in extraembryonic membranes decreased during embryogenesis, that in the placenta remained unchanged. Immunohistochemical studies showed that Mk was located in the yolk sac and in the amnion at 11.5 days gestation. PTN mRNA expression was weak in extraembryonic membranes and was scarcely detectable in the placenta. Western blot analysis revealed the presence of MK in amniotic fluid and cerebrospinal fluid, in amounts of more than 1 microgram/ml, raising the possibility that MK delivered by these fluids participates in the regulation of organogenesis. Transport of MK from the site of its synthesis appears to also occur in the adult kidney, since MK mRNA and the MK protein are localized in different regions of the kidney.

Amino Acid Sequence↗
PubMed1995

Dissociated motor loss in forearm and hand muscles: case report.

A 27-year-old man was diagnosed with the unilateral dissociated motor loss of the forearm and hand muscles. His medical image findings were completely different from those of other reports such as so called flexion myelopathy (abnormal anterior displacement of the dura mater and the spinal cord against the posterior wall of the vertebral body in neck flexion). Our patient demonstrated lateral shift of the spinal cord to the right attributed to high thoracic scoliosis and disk herniation at the level of C6-7. The right side of the spinal cord was compressed between the disk herniation and the right lamina. In this condition, circulatory insufficiency probably occurred and resulted in damage of the anterior horn, which was selectively vulnerable for ischemia in the spinal cord.

Adult↗
PubMed1995

Effect of sonicated material from Fusobacterium nucleatum on the functional capacity of accessory cells derived from dental pulp.

Fusobacterium nucleatum-derived components were studied for their effect on the ability of accessory pulpal cells to induce T-lymphocyte proliferation. In initial experiments, spleen cells were used to establish concentration ranges at which testing of the effect of the bacterial components would be suitable. At low concentrations, bacterial substances induced a stimulatory effect on the proliferation rate of spleen cells, but not when purified T-lymphocytes were incubated in the presence of concanavalin A and pulpal accessory cells. At increasing concentrations, a dose-dependent reduction was observed. Pretreatment with the bacterial products for 4 h gave a stimulatory effect in the absence of concanavalin A for both spleen cells and T-lymphocytes. Removal of low-molecular weight components (<3.5 kDa) did not influence the inhibitory effect, whereas preheating the bacterial substances to 100 degrees C eliminated the observed inhibition. Findings show that heat-sensitive, high-molecular-weight components of F. nucleatum can evoke a concentration-dependent stimulatory or suppressive effect on the proliferation rate of T-lymphocytes in the presence of accessory cells derived from the dental pulp.

Analysis of Variance↗
PubMed1995

Induction of carcinomas and sarcomas by 9,10-dimethyl-1,2-benzanthracene administration into the hamster maxillary sinus.

To determine whether the local administration of 9,10-dimethyl-1,2-benzanthracene (DMBA) into the hamster maxillary sinus induced carcinoma at the injected site, hamsters were injected with 30 microliters of 0.5% solution of DMBA in dimethyl sulfoxide (DMSO) through the infraorbital foramen into the maxillary sinus once weekly for 10 weeks (Group 2). Another group of hamsters (Group 1) received similar injections of 30 microliters of DMSO only. In a third group of animals (Group 3), a roll of oxycellulose was inserted into the maxillary sinus and 40 microliters of a 2% solution of DMBA in DMSO was injected once. Sinonasal carcinomas were demonstrated in 73% (8/11) of the hamsters in Group 2 and sarcomas were shown in 73% (8/11) of the hamsters in Group 3, as well as some carcinomas. No tumors were seen in the Group 1 hamsters. Histologic examination revealed squamous cell carcinomas arising from the surface epithelium and submucous glands of the nasal cavity and maxillary sinus. These findings indicate that the intrasinal administration of a 0.5% solution of DMBA in DMSO is a reliable method for inducing maxillary sinus cancer.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1995

Proteolytic enzymes in salivary extravasation mucoceles.

We examined the content of type IV collagenases and plasminogen activators (PAs) in luminal fluid of four extravasation mucoceles by means of gelatin or casein zymography. Immunohistochemical staining for type IV collagenases and PAs was performed to identify the possible source of these enzymes. The luminal fluid examined by gelatin zymography showed a high level of type IV collagenases compared with saliva from Wharton's duct. PAs were detected in only one of the cases by casein zymography, and none was detected in the saliva. By immunohistochemical staining, type IV collagenases and PAs were detected in duct and myoepithelial cells of the adjacent salivary gland and in macrophages and fibroblasts of the cyst wall. The results suggest that proteolytic enzymes are involved in the pathogenesis of mucoceles.

Adolescent↗
PubMed1995

Effects of testosterone on tumor induction and epidermal growth factor production in the mouse submandibular gland.

To determine whether testosterone administration was capable of modifying salivary gland carcinogenesis, female mice were given 1 mg of 9,10-dimethyl-1,2-benzanthracene (DMBA) into the left submandibular gland and then Group 1 mice received 5 mg of testosterone propionate and Group 2 mice received vehicle, olive oil, subcutaneously for 8 weeks. Twelve weeks after the start of the experiment, the weight of the left submandibular gland of the Group 2 mice was greater than that of the Group 1 mice. The incidences of submandibular gland carcinoma in Groups 1 and 2 were 41% (12/29) and 57% (17/30), respectively. Epidermal growth factor (EGF) levels of the left submandibular gland were significantly higher in Group 1 as compared with Group 2. These findings indicate that testosterone increases the production of EGF in the DMBA-injected submandibular gland, but does not promote the development of submandibular gland carcinoma.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1995

[Quinolone-resistant mutations in Neisseria gonorrhoeae].

For 10 strains of Neisseria gonorrhoeae exhibiting decreased susceptibility to new quinolones (MIC, > or = 0.1 microgram/ml) isolated and preserved from patients with gonococcal urethritis during the period from February 1991 through January 1992. We investigated the mechanisms for development of resistance to new quinolones. After selecting 3 PCG-sensitive and new quinolone-resistant strains from among these strains, we first carried out transformation experiments of N. gonorrhoeae using a plasmid carrying the E. coli gyrA gene. We then determined the base sequence on the N. gonorrhoeae gyrA gene by PCR method. Of the 3 strains in which transformation experiments were carried out, 2 strains yielded transformants, one of which was 8 times more sensitive to norfloxacin (NFLX) than the original strain, and it was assumed that this strain has a mutation in the gyrA gene. In our study of the base sequence on the N. gonorrhoeae gyrA gene using the PCR method, both strains had the mutation of Ser 83 (TCC)-->Phe (TTC), and in addition to this mutation of Ser-->Phe, one other strain had the mutation of Asp-87 (GAC)-->Gly (GGC). This type of mutation of quinolone-resistant N. gonorrhoeae on the gyrA gene has high homology with the mutations reported for Escherichia coli and other strains and there appears to be a close correlation between the increasing frequency of use of the new quinolones in this country and the spread of such resistant strains of N. gonorrhoeae.

Drug Resistance, Microbial↗
PubMed1995

[An outbreak of Pontiac fever due to Legionella pneumophila serogroup 7. I. Clinical aspects].

In August 1994, an epidemic of acute febrile illness occurred at the Education Center Building of a company in Shibuya-ku, Tokyo. All 43 trainees attended in two groups and 2 staff members of the Center fell ill. The 45 patients came to one of our hospitals in two groups, and 35 patients were treated. The patients were 4 males and 31 females, and the average age was 29.0 years. The duration until falling ill was 36 to 90 hours after entering the Center. Symptoms were fever, lumbago arthralgia, headache, dyspnea, general fatigue, etc. Physical examination revealed slightly injected mucosa of the pharynx in a patient who complained of a sore throat. On laboratory examination, leukocytosis with a left shift of the nucleus and elevation of serum CRP levels were found. Erythromycin (600 mg, daily) and nonsteroidal antiinflammatory drugs (NSAIDs) were given by mouth to almost every patient. Two patients were hospitalized. The illness was self-limited, generally lasting from two to five days. Strains of legionellae isolated from the water of the cooling tower located at the top of the Center, were identified as L. pneumophila serogroup 7. Since seroconversion in a patient against the cooling tower strain from 1:16 to 1:256 was determined and the clinical courses agreed with the definition of Pontiac fever by Glick et al, we concluded that the epidemic was an outbreak of Pontiac fever due to L. pneumophila serogroup 7. Pontiac fever is considered to be one of the community-acquired diseases. Thus, we have to note that Pontiac fever may be misdiagnosed as we examine patients who complain of the symptoms noted above.

Adolescent↗
PubMed1995

Induction of apoptosis of T cells by infecting mice with murine cytomegalovirus.

Cytomegalovirus (CMV) is associated with several lymphocyte dysfunctions, but the precise mechanisms of the dysfunctions are still unclear. To elucidate the mechanisms, a cell cycle-DNA content analysis was performed on splenic T cells of murine CMV (MCMV)-infected BALB/c mice. T cells from mice infected with 3 x 10(3) PFU of MCMV contained a higher percentage of hypodiploid nuclei after 12 or 24 h of culture than those from naive mice. T cells from infected mice also contained a larger amount of fragmented DNA. Taken together, these results suggested that infection with MCMV induced the apoptotic cell death of T cells. This induction of apoptosis accounted for the dysfunction of lymphocytes, at least partially. Flow cytometric analysis showed that T cells as well as B cells from MCMV-infected mice expressed an augmented level of Fas antigen, an apoptosis-associated cell surface molecule, which might be the cause of the apoptosis of cells. T cells from MCMV-infected C57BL/6-lpr/lpr mice with mutations at the lpr/fas locus, however, also showed a substantial level of apoptosis, which was reproducibly lower than that seen in C57BL/6 mice. Therefore, it was suggested that the Fas-mediated pathway contributed to but was not sufficient for the induction of apoptosis and that mechanisms other than the Fas-associated pathway were also involved in the induction of apoptosis.

Animals↗
PubMed1995

High affinity IgE receptor-mediated prostaglandin E2 production by monocytes in atopic dermatitis.

High affinity IgE receptor (Fc epsilon R I) expression on monocytes and its upregulation on monocytes from patients with atopic dermatitis (AD) have been recently reported. In this study, we investigated whether prostaglandin E2 (PGE2) release from AD monocytes was Fc epsilon R I-dependent or not. The monocytes were stimulated with anti-Fc epsilon R I monoclonal antibody (mAb) and anti-Fc epsilon R II mAb. Cross-linking of Fc epsilon R I, but not that of Fc epsilon R II induced PGE2 release from monocytes. In order to confirm that the PGE2 release is IgE-dependent, stimulation with IgE+anti-IgE, IgG+anti-IgG and immune complexes made by incubation with AD patients' serum and recombinant Der fII (rDer fII-IC) were carried out in the culture. Significant PGE2 release by all the stimulants was observed, as compared with spontaneous release. PGE2 release by immune complex made by incubation with IgE-absorbed AD serum and rDer fII was much lower than that by rDer fII-IC. In monocytes from nonatopic donors, significant PGE2 release was observed when stimulated with IgE+anti-IgE, IgG+anti-IgG, rDer fII-IC, but not with anti-FC epsilon R I mAb and anti-Fc epsilon R II mAb. However, the release were significantly lower than respective PGE2 releases from AD monocytes. Taken together, cross-linking of Fc epsilon R I and IgE induced a PGE2 release from monocytes. This is a first report demonstrating an Fc epsilon R I-dependent mediator release from monocytes of AD patients.

Antigen-Antibody Complex↗
PubMed1995

Role of the deletion of polymorphism of the angiotensin converting enzyme gene in the progression and therapeutic responsiveness of IgA nephropathy.

Studies conducted over the last decade demonstrated variable therapeutic efficacy of angiotensin converting enzyme (ACE) inhibitor on the progression of glomerular diseases, including IgA nephropathy. In this study, among patients with biopsy-proven IgA nephropathy, 53 patients in whom creatinine clearance had been monitored over 5 yr were recruited for study. These patients were classified into two groups according to whether or not renal function had declined as determined by the slope of creatinine clearance against time: group 1 had stable renal function; group 2 had declining renal function (average: -6.7 +/- 1.3 ml/min/yr). 21 of 53 patients were treated with ACE inhibitor and followed for 48 wk. Gene polymorphism consisting of insertion (I) or deletion (D) of a 287-bp DNA fragment (presumed to be a silencer element) of the ACE gene was determined by PCR. 46 age-matched individuals without history of proteinuria were analyzed as controls. The DD genotype was significantly more frequent in group 2 (43%) than in controls (7%) or group 1 patients with stable renal function (16%). 48 wk after ACE inhibitor administration, proteinuria significantly decreased in patients with DD genotype but not in those with ID or II genotypes. The results indicate that deletion polymorphism in the ACE gene, particularly the homozygote DD, is a risk factor for progression to chronic renal failure in IgA nephropathy. Moreover, this deletion polymorphism predicts the therapeutic efficacy of ACE inhibition on proteinuria and, potentially, on progressive deterioration of renal function.

Adult↗
PubMed1995

Gene targeting in mice reveals a requirement for angiotensin in the development and maintenance of kidney morphology and growth factor regulation.

Elevated levels of endogenous angiotensin can cause hypertensive nephrosclerosis as a result of the potent vasopressor action of the peptide. We have produced by gene targeting mice homozygous for a null mutation in the angiotensinogen gene (Atg-1-). Postnatally, Atg-1- animals show a modest delay in glomerular maturation. Although Atg-1- animals are hypotensive by 7 wk of age, they develop, by 3 wk of age, pronounced lesions in the renal cortex, similar to those of hypertensive nephrosclerosis. In addition, the papillae of homozygous mutant kidneys are reduced in size. These lesions are accompanied by local up-regulation of PDGF-B and TGF-beta1 mRNA in the cortex and down-regulation of PDGF-A mRNA in the papilla. The study demonstrates an important requirement for angiotensin in achieving and maintaining the normal morphology of the kidney. The mechanism through which angiotensin maintains the volume homeostasis in mammals includes promotion of the maturational growth of the papilla.

Aging↗