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Biomedical subjects

S Yamada

Publications and source records attributed to S Yamada.

At least 541 records · Page 30Linked to original sources
PubMed1998

Analysis of mumps vaccine failure by means of avidity testing for mumps virus-specific immunoglobulin G.

To characterize patients with mumps vaccine failure, avidity testing was performed with the Enzygnost Anti-Parotitis Virus/IgG kit using a single-dilution-6 M urea denaturation method. Five groups of patients were tested. Group 1 consisted of 29 patients with primary mumps infections; group 2 was 20 children and adults with a definite history of natural infection; group 3 was 7 patients with a recent mumps vaccination, 1 of whom developed parotid gland swelling and aseptic meningitis; group 4 was 14 patients with mumps vaccine failure; and group 5 was 6 patients with recurrent episodes of parotitis in addition to a history of vaccination. On the basis of the results of groups 1 and 2, an avidity of </=31% was determined to be low, and >/=32% was determined to be high. Avidity maturation from low to high appears to occur around 180 days after the acute illness. The results of group 3 showed that the vaccine-induced immunoglobulin G (IgG) had very low avidity. Among the 14 patients in group 4, 12 patients, including 7 with a positive IgM response, were diagnosed as having secondary vaccine failures. The results of group 5 suggested the possibility that the avidity of the mumps vaccine-induced IgG remains low or borderline. These results showed that secondary mumps vaccine failure occurs not infrequently, even among school age children under condition in which the vaccine coverage is low (i.e., 33% in our study population), and therefore, vaccinees are prone to be exposed to wild-type viruses. Avidity testing should provide information useful for the analysis of mumps virus infections.

Adolescent↗
PubMed1998

Analysis of mycoplasmal pleural effusion by the polymerase chain reaction.

Ten pediatric patients with mycoplasmal pleuritis were tested for the presence of Mycoplasma pneumoniae in pleural fluid by the polymerase chain reaction (PCR). Three of the four PCR positive cases left a persistent consolidation. The remaining one was an infant who required mechanical ventilation. PCR may be useful in predicting delayed resolution of roentgenographic abnormality.

Adolescent↗
PubMed1998

Effect of Ganoderma lucidum on postherpetic neuralgia.

Administration of hot water soluble extracts of Ganoderma lucidum (GI) (36 to 72 g dry weight/day) decreased pain dramatically in two patients with postherpetic neuralgia recalcitrant to standard therapy and two other patients with severe pain due to herpes zoster infection.

Aged↗
PubMed1998

Physiological roles of integrin alpha 6 beta 1 in ovarian functions.

We previously reported that human ovarian cells express integrin beta 1 families. The physiological role(s) of integrins was investigated using in vitro human granulosa cell culture and in vivo mouse ovulation model. In human luteinizing granulosa cell culture obtained from the patients undergoing in vitro fertilization treatment, laminin, which is a ligand for integrin alpha 6 beta 1, suppressed the production of progesterone by granulosa cells. On the other hand, the anti-alpha 6 monoclonal antibody (mAb) GoH3, which partially inhibits the interaction between integrin alpha 6 beta 1 and laminin, enhanced production of progesterone by 2-fold of the control under the culture with laminin, indicating that integrin alpha 6 beta 1 regulates the luteinization of human granulosa cell during the periovulatory phase. In an immature superovulated 13-day-old ICR (CD-1) mice model, intraperitoneal administration of GoH3 induced successful ovulation, whereas no ovulation was observed in the GoH3-nontreated groups, showing that integrin alpha 6 beta 1 is related to gonadotropin-induced follicular growth. These findings suggest that the interaction between integrin alpha 6 beta 1 and laminin plays an important role in the corpus luteum formation and follicular growth.

Animals↗
PubMed1998

Conditioned medium from HepG2 cells transfected with human apolipoprotein(a) gene stimulates growth of human vascular smooth muscle cells: effects of overexpression of human apolipoprotein(a) gene.

Lipoprotein(a) [Lp(a)] is well known to stimulate growth of vascular smooth muscle cells (VSMCs), resulting in atherosclerosis. Its mechanism is postulated to be decreased in active transforming growth factor (TGF)-beta. However, the exact mechanisms and cellular processing from apolipoprotein(a) [apo(a)] to Lp(a) have not yet been clarified because no cultured cells producing apo(a) are available. Therefore, it is necessary to establish apo(a)-producing cells to study the role of apo(a). We evaluated the effects of overexpression of human apo(a) gene on human aortic VSMC growth. First, we tested whether transfection of apo(a) gene into human hepatoma cells, HepG2 cells, producing human apoB resulted in the formation of Lp(a). Transfection of apo(a) gene into HepG2 cells resulted in detectable levels of Lp(a) in the medium, as assessed by ELISA and Western blot, whereas no Lp(a) was detected in the medium of HepG2 cells transfected with control vector and untransfected HepG2 cells. Expression of apo(a) mRNA was also confirmed by reverse transcription-polymerase chain reaction. In contrast, Western blotting showed a single band detected by specific anti-apo(a) antibody, but not anti-apoB antibody, in the medium of apo(a)-transfected VSMCs. These results demonstrate that Lp(a) can be formed from apo(a) on HepG2 cells, whereas transfection of apo(a) gene into VSMCs resulted in the production of apo(a) alone but not Lp(a). Next, we examined the biological effects of overexpression of apo(a) gene on growth of VSMCs and endothelial cells. Incubation of cultured medium of HepG2 cells transfected with apo(a) gene with human VSMCs or endothelial cells resulted in a significant increase in cell number compared with the conditioned medium of HepG2 cells transfected with control vector. In contrast, transfection of apo(a) gene directly into VSMCs caused no significant effect on VSMC growth. Therefore, we measured TGF-beta concentration in the conditioned medium of VSMCs. However, using ELISA, only latent but not active TGF-beta was detected in the medium of VSMCs. Moreover, addition of neutralizing anti-TGF-beta antibody did not alter VSMC growth. These results suggest that Lp(a) could stimulate growth of VSMCs via the independent mechanisms from the inhibition of TGF-beta activation. Overall, these data demonstrate that overexpression of apo(a) gene in cells producing apoB results in formation of Lp(a), resulting in a mitogenic action on human endothelial cells and VSMCs. These results provide new information to understand the mechanisms of the mitogenic action of Lp(a) and suggest the role of Lp(a) in the pathogenesis of atherosclerosis.

Apolipoproteins↗
PubMed1998

Enteric lesions induced by different pseudorabies (Aujeszky's disease) virus strains inoculated into closed intestinal loops of pigs.

Three different strains of pseudorabies (Aujeszky's disease) virus were inoculated into ligated closed loops in the jejunum and ileum of five specific-pathogen-free pigs. Infected areas were compared with respect to distribution of histologic lesions and pseudorabies virus antigen. Two wild-type strains of pseudorabies virus produced enteric lesions consisting of necrosis of the subepithelial macrophages in the basilar crypt epithelium, necrosis of the lymphoid follicles in the Peyer's patches, degeneration of the epithelial cells in the crypt and villi, degeneration of the neuronal cells in the myenteric plexuses, and formation of intranuclear inclusion bodies on postinoculation days 2-4. Pseudorabies virus antigen was initially detected in subepithelial macrophages of the dome of Peyer's patches on postinoculation day 2 and subsequently extended to superficial epithelium and deeper into the lymphoid follicles and myenteric plexuses on postinoculation days 3-4. Many pseudorabies virus particles were also detected in the center of their necrotic foci. However, 1 mutant strain (ara-T-resistant) of pseudorabies virus did not produce enteric lesions. The results suggest that the primary target of infection by wild-type strains of pseudorabies virus might be the macrophages distributed in the subepithelial area of the dome Peyer's patches.

Animals↗
PubMed1998

Endothelin-converting enzyme-1 is expressed on human ovarian follicles and corpora lutea of menstrual cycle and early pregnancy.

We have previously reported that membrane-bound amino- and carboxypeptidases were expressed on the human follicles and corpora lutea (CL), and we proposed that these peptidases are involved in ovarian functions, probably by regulating the extracellular peptide concentrations. In this study, we examined the expression of endothelin-converting enzyme-1 (ECE-1) on human follicles and CL, which is a membrane-bound endopeptidase and is known to convert big endothelin-1 to endothelin-1. In the preovulatory follicles, immunohistochemical study showed that ECE-1 was expressed, with moderate intensity, on the theca interna cells and weakly on the granulosa cells. In the menstrual and pregnant CL, ECE-1 was highly expressed on both large and small luteal cells, indicating that ECE-1 expression increases during luteinization. Western blotting analysis revealed that the molecular mass of the ECE-1 extracted from the menstrual CL was 130 kDa and that ECE-1 was more strongly expressed on the CL in early and midluteal phases than the CL in late luteal phases. In the isolated luteinizing granulosa cells obtained from patients undergoing in vitro fertilization, ECE-1 was immunohistochemically detected on their cell surface. The activity of ECE-1 was also detected on cultured luteinizing granulosa cells by measuring endothelin-1 production from its precursor. The activity of ECE-1 was significantly enhanced by the treatment of human CG (10 U/mL) and interleukin (IL)-1 (10 ng/mL) during 4-day culture, whereas no significant alteration was observed by IL-4 (10 ng/mL) and IL-10 (10 ng/mL) treatment. These results indicate that ECE-1 is a cell surface differentiation-related molecule of human granulosa and of theca interna cells and suggest that the expression of ECE-1 is regulated by LH/human CG and cytokines.

Adult↗
PubMed1998

Absence of germ-line mutations of the multiple endocrine neoplasia type 1 (MEN1) gene in familial pituitary adenoma in contrast to MEN1 in Japanese.

Germ-line mutations of the MEN1 gene were analyzed in five cases of familial and four cases of sporadic multiple endocrine neoplasia type 1 (MEN-1), six cases in three independent pedigrees of familial pituitary adenoma without MEN-1, and three cases of familial isolated primary hyperparathyroidism (FIHP) in Japanese. Eight different types of germ-line mutations in all nine cases of MEN-1 were distributed in exons 2, 3, 7, and 10 and intron 7 of the MEN1 gene. Loss of heterozygosity (LOH) on 11q13 was detected in all nine tumors of these cases with microsatellite analysis. No germ-line mutation of the MEN1 gene was detected in three pedigrees of familial pituitary adenoma and three cases of FIHP. LOH on 11q13 was detected in two cases in one pedigree of familial pituitary adenoma, and one of them showed a heterozygous somatic mutation of the MEN1 gene. No LOH on 11q13 was detected in three cases of FIHP. Based on these, we conclude that the loss of function of menin is etiological for familial or sporadic MEN-1, but not for FIHP or most familial pituitary adenoma without MEN-1.

Adenoma↗
PubMed1998

Analysis of loss of heterozygosity on chromosome 11 and infrequent inactivation of the MEN1 gene in sporadic pituitary adenomas.

To investigate the role of tumor suppressor genes in sporadic pituitary adenomas, we first analyzed loss of heterozygosity on 11q13 with microsatellite analysis in 31 tumors. Loss of heterozygosity on 11q13 was detected in 1 mixed GH/PRL adenoma, and the somatic 22-bp deletion of the multiple endocrine neoplasia type 1 (MEN1) gene encoding menin was detected in this tumor. Trisomy 11 suggested by the decreased mean allelic ratios of 66% or 65% for 16 or 13 microsatellite markers, respectively, in 2 of 31 pituitary adenomas was confirmed by interphase fluorescence in situ hybridization. Screening for mutations of the MEN1 gene did not find mutations with PCR-single strand conformation polymorphism analysis in other pituitary adenomas retaining heterozygosity on 11q13. Based on these, it is concluded that inactivation of the MEN1 gene comprises a rare etiology for tumorigenesis of the pituitary gland, and that trisomy 11 or another gene(s) may contribute to the pathogenesis of sporadic pituitary adenomas.

Adenoma↗
PubMed1998

Effect of relatively low dose amiodarone therapy on left ventricular function in patients with ventricular tachyarrhythmias.

The effect of oral amiodarone (AMD) therapy on left ventricular (LV) function was evaluated retrospectively in Japanese patients with ventricular tachyarrhythmias and congestive heart failure. Seventeen patients were treated with oral AMD (maintenance dose 191+/-52mg/day) for more than 12 months. Fractional shortening (FS) on echocardiography revealed a trend towards an increase in the short-term (3 months) (p=0.06), but was not significant in the long-term follow-up period (more than 12 months) after AMD therapy. In 8 patients with 1 episode of myocardial infarction, FS revealed a trend towards an increase (p=0.09). In all of the 4 patients with dilated cardiomyopathy whose LV end-diastolic diameter was increased, FS was decreased in the long-term follow-up. Neither hospitalization frequency nor New York Heart Association classification were reduced by AMD therapy. In conclusion,oral AMD therapy did not cause LV function to recover significantly and could not improve the clinical course in patients with ventricular tachyarrhythmias. However, if the underlying disease is not progressive, AMD therapy may improve LV function.

Administration, Oral↗
PubMed1998

Activation of the 20S proteasome of Xenopus oocytes by cardiolipin: blockage of the activation of trypsin-like activity by the substrate.

The effects of an activator, cardiolipin, on the three peptidase activities of the 20S proteasome of Xenopus oocytes were examined. The trypsin-like activity was activated when the enzyme was treated with cardiolipin before the addition of the substrate, but there was no appreciable activation when cardiolipin was added concomitantly with the substrate. On the other hand, the chymotrypsin-like peptidase and peptidylglutamylpeptide hydrolase (PGPH) were activated regardless of the sequence of addition. When very low concentrations of the substrate (e.g. 0.1-0.5 microM; about 1/100 of the K(m)) were used, cardiolipin strongly activated trypsin-like peptidase by the simultaneous addition but not after substrate addition. These results suggest that the trypsin-type substrate produces a conformational change in the enzyme in a concentration-dependent manner which makes the activator sites inaccessible to cardiolipin.

Animals↗
PubMed1998

Colony-stimulating factor-1 stimulates the fusion process in osteoclasts.

Colony-stimulating factor-1 (CSF-1), also called macrophage colony-stimulating factor, is required for growth, differentiation, activation, and survival of cells of the mononuclear phagocytic system. This cytokine has been shown to be essential for osteoclast development as well as for inducing both proliferation and differentiation of osteoclast progenitors. It also sustains survival of mature osteoclasts and stimulates spreading and migration of these cells. In the present in vitro study, the formation of large tartrate-resistant acid phosphatase (TRAP)-positive cells with a high number of nuclei was observed when osteoclasts isolated from rat long bones were incubated with CSF-1. These large cells, cultured on plastic, bind calcitonin and form F-actin along the edges of the cells. Fusion to such large TRAP-positive multinucleated cells in the presence of CSF-1 and the formation of pits were also observed on dentine slices. Quantitative data obtained from cultures on plastic demonstrated that the number of osteoclasts slightly increased in the course of 72 h in the presence of 250 pM CSF-1, whereas it decreased rapidly after 24 h in the absence of CSF-1, which confirms that this cytokine is required for the survival of osteoclasts. The number of nuclei per osteoclast was maximal after 16 h of incubation with CSF-1, namely twice the value found in the absence of CSF-1. The maximal effect of the cytokine on the fusion process was observed at a concentration of 250 pM. A calculation of the medians of the average frequency of nuclei distribution per osteoclast resulted in four nuclei per osteoclast in the absence and six in the presence of CSF-1. Genistein and herbimycin A, inhibitors of tyrosine kinases, inhibited the fusion induced by CSF-1. The data suggest that CSF-1 induces osteoclast fusion and that tyrosine kinase(s) are involved in this process. The fusion process may continue throughout the entire life of an osteoclast.

Animals↗
PubMed1998

Bestatin, an aminopeptidase inhibitor, promotes follicular growth and ovulation suppressed by stress in mice.

We previously reported that the intraperitoneal and intrabursal administration of bestatin, an aminopeptidase inhibitor, enhanced follicular growth and ovulation in immature mice. In this study, we examined the effect of bestatin on follicular growth and ovulation under the conditions in which the ovarian response to gonadotropins was suppressed. Immature female mice were exposed to 72-h continuous lighting (on days 20-22 of life), or to 24-h starvation (on day 20). On days 20-22, bestatin (4 mg/ml, 100 microl) or PBS (100 microl) was administered ip. 4 times and pregnant mare serum gonadotropin (PMSG, 5 IU) and hCG (5 IU) were given on days 21 and 23, respectively. The numbers of ovulated oocytes per mice were significantly attenuated by both stresses. Bestatin significantly enhanced the numbers of ovulated oocytes under both lighting (49.5+/-7.0 vs. 28.0+/-5.5) and starvation (28.6+/-2.6 vs. 20.2+/-2.0) stresses (with vs. without bestatin, P<0.05). When follicular development was stimulated by PMSG (20 IU) on day 21, the serum estradiol concentration on day 23 was also suppressed by both stresses, but enhanced by bestatin under lighting (231.3+/-36.0 vs. 111.0+/-23.0 pg/ml) and starvation (151.9+/-8.8 vs. 90.7+/-15.4 pg/ml) stresses (with vs. without bestatin, P<0.01). Northern blot analysis revealed that the expression of P450arom-mRNA in the ovaries induced by PMSG (20 IU) was increased on day 23 by treatment with bestatin under starvation stress. These results indicated that stress inhibited the ovarian response to gonadotropins and that bestatin restored the response suppressed by stress.

Aminopeptidases↗
PubMed1998

Dynamics of serum immunoglobulin G avidity for Porphyromonas gingivalis in adult periodontitis.

The purpose of this study was to examine avidity of immunoglobulin G (IgG) antibody for surface antigens of Porphyromonas gingivalis in sera from patients with adult periodontitis. The antigens used were whole cell antigens, lipopolysaccharides (LPS), and fimbriae of non-invasive P. gingivalis ATCC 33277 and invasive 16-1. Serum IgG titers for the P. gingivalis antigens were measured by enzyme-linked immunosorbent assay (ELISA) before and after periodontal initial preparation. IgG avidity was measured by diethylamine dissociation ELISA. IgG titers for the whole cell antigens of 16-1, LPS, and the fimbria antigens from both P. gingivalis strains were significantly higher in the patient group than those in the control group, whereas values for avidities were significantly lower in patient sera. Although we found a statistically significant decrease in the IgG titers of patients following initial preparation, avidities against the fimbria antigen of invasive 16-1 strain increased. The present study showed that IgG antibodies elicited in patients were different in their ability to respond to invasive P. gingivalis 16-1 and to non-invasive 33277. The patient sera with high IgG titers demonstrated low values for avidity, suggesting that IgG responses in patients play a limited role in colonization inhibition or elimination of P. gingivalis. The data indicate that periodontally healthy individuals may have highly functional antibodies which may protect against P. gingivalis colonization. Our findings suggest that the ability to produce functional antibodies in the patient group is lower than that in the periodontally healthy group, but the functional antibodies can be induced by the initial preparation.

Adult↗
PubMed1998

Irreversible potent activation and reversible inhibition of trypsin-like activity of 20S proteasome purified from Xenopus oocytes by fatty acid.

The 20S proteasome purified from animal cells has various latent peptidase activities. Fatty acids such as linoleic, linolenic and oleic acids strongly activate both the chymotrypsin-type and peptidylglutamylpeptide (PGP) hydrolase-type activities, but have been reported to have little activation or inhibition of the trypsin-type activity. We show here that an increase of the fatty acid concentration produces activation of chymotrypsin-type and PGP hydrolase-type in a biphasic fashion: no effect until the threshold concentration and then a sharp activation. In contrast, the trypsin-type activity was markedly inhibited at low concentrations of fatty acid, slightly activated at higher concentrations, and inhibited again at even higher concentrations. The inhibition was removed when the concentration of fatty acid was reduced by dilution after pre-incubation with the fatty acid. As a result, the activation pattern became biphasic, which was identical to that of chymotrypsin-type and PGP hydrolase-type activities. These results suggest that in the chymotrypsin-type and PGP hydrolase-type peptidase fatty acids bind first to a class of sites without direct effect on the peptidase activity, but after saturation of this class it permits more fatty acid to bind to another class of sites involved in the activation. In the trypsin-type peptidase an additional class of fatty acid binding sites is uniquely present, which is involved in the enzyme inhibition. The dilution procedure described above removes the fatty acid molecules bound to the inhibition sites, but not the fatty acid molecules bound to the activation sites; this results in the fatty acid activation profile indistinguishable from that of the chymotrypsin- and PGP hydrolase-type peptidases.

Animals↗
PubMed1998

Autopsy findings in a long-term survivor with glioblastoma multiforme--case report.

Autopsy detected no tumor tissues in a patient who died 6.5 years after the diagnosis of glioblastoma multiforme. A 54-year-old male developed left hemiparesis one month prior to admission. Computed tomography demonstrated a cystic lesion in the right frontal region with irregular ring-like enhancement. The tumor was extensively removed together with the surrounding tissue followed by irradiation (whole brain 32.4 Gy, local 28.8 Gy), and intravenous administration of interferon-beta. Histological examination confirmed the diagnosis of glioblastoma multiforme. He died of accidental head trauma 6.5 years after surgery. Autopsy of the brain detected no evidence of glioblastoma multiforme. The only findings were cerebral edema and hematoma caused by head trauma, as well as histological changes due to radiation damage. This case apparently confirms the histological disappearance of tumor tissue in a long-term survivor with glioblastoma multiforme.

Brain Neoplasms↗
PubMed1998

Surgical techniques for arteriovenous malformations in functional areas: focus on the superior temporal gyrus.

Direct surgical intervention of arteriorvenous malformations (AVMs) in functional areas has been accepted as a standard mode of treatment. However, safe and successful intervention requires that such factors as exact location, size, vascular supply, and drainage be considered. Importantly, surgical techniques must be individualized to each patient, based on hemodynamic anatomy of the AVM. This paper discusses AVMs in the superior temporal lobe, which have a complex neuronal anatomy and circulatory system; the authors present 22 patients with AVMs of various sizes and describe the surgical techniques specific for the indicated location. Surgical procedures adhered to the following principles: 1) avoid brain tissue removal; 2) preserve microcirculation; 3) maintain circulation of the isolated major draining vein to access the AVM core; 4) compartmental isolation; and 5) preservation of functional area cortex covering the AVM. All patients underwent total resection except one, who had a subtotal resection. Neurological and occupational recovery was remarkable except for partial hemianesthesia in one patient; two patients are still in rehabilitation. This is the first description of a direct surgical approach to AVMs in the superior temporal gyrus, where management is challenging because the lesions may extend elsewhere, such as to Broca's and Wernicke's areas. The results suggest that the procedure is promising.

Adolescent↗