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Biomedical subjects

A Yamada

Publications and source records attributed to A Yamada.

At least 397 records · Page 22Linked to original sources
PubMed1993

[An autopsy case developing both marked stenosis of the coronary artery and dilated phase of hypertrophic cardiomyopathy].

An autopsy case involving the dilated phase of hypertrophic cardiomyopathy (HCM) is reported. This case was also complicated with a lesion similar to fibromuscular dysplasia of the coronary artery. A 37 year-old male died of cardiac insufficiency and an autopsy was performed. Macroscopically, both atriums and ventricles were dilated and the walls of both ventricles were markedly thickened. Also, the coronary artery was almost completely obstructed. Histological examination revealed bizarre myocardial hyperplasia with disorganization and marked fibrosis of the myocardium. The coronary artery showed intimal fibrous thickening with increase in elastic fibers and smooth muscle cells. There were similar lesions in other arteries examined; the renal arteries, external iliac arteries, pulmonary arteries and aorta. We think that this lesion of the coronary artery plays an important part in the progression from hypertrophic cardiomyopathy to dilated cardiomyopathy.

Adult↗
PubMed1993

LFA-1 expression on exocrine glands as a potential novel marker of malignant disease.

The lymphocyte function associated antigen 1 has been found only on leukocytes and lymphoid tissues; however, the expression of lymphocyte function associated antigen 1 on nonhematopoietic cells has not been reported previously. In this study, immunohistochemical expression of lymphocyte function associated antigen 1 was examined on various tissues from 35 patients with malignant diseases and 36 patients with benign diseases including benign tumors. The expression of lymphocyte function associated antigen 1 was found on various exocrine tissues (eg, gastric glands, bronchial epithelium, alveolar epithelium, duodenal glands, bile ducts, pancreatic acini, and salivary glands) uninvolved by tumor in patients with malignant diseases. Localization of lymphocyte function associated antigen 1 was limited to the exocrine glands and differed from tissue-infiltrating leukocytes. The expression of lymphocyte function associated antigen 1 on exocrine tissues was confirmed in all 35 cases of malignant diseases that were examined. These included a wide spectrum of carcinomas and hematopoietic tumors. In contrast, none of the 36 cases with benign diseases examined expressed lymphocyte function associated antigen 1 on their exocrine glands. These results indicate a strong correlation between lymphocyte function associated antigen 1 expression on exocrine glands and malignant disease. The expression of lymphocyte function associated antigen 1 on nonhematopoietic cells was further confirmed in nonhematopoietic cell lines. Two of 19 nonhematopoietic cell lines (MKN45 and PANC-1; exocrine gland cell lines) examined expressed lymphocyte function associated antigen 1 on both cell surface and cytoplasm. These results suggested that immunohistochemically defined lymphocyte function associated antigen 1 molecules on nontumorous exocrine gland cells are a potential marker for the presence of malignant diseases.

Antibodies, Monoclonal↗
PubMed1993

[Event-related potentials in progressive supranuclear palsy].

Abnormal event-related potential (ERP) has been reported in several types of dementing illness including Parkinson's disease (PD) and progressive supranuclear palsy (PSP). In this paper we report the result of EPR recordings obtained in normal control subjects (14 cases) and in patients with PSP (6 cases) and PD (32 cases). ERPs were recorded from 13 scalp electrodes, using the acoustic odd-ball paradigm. All PD patients were in early stage (Yahr stage 1 to 2), and all PSP patients were in the mild-to-moderate state. In control subjects and PD patients P3 was normal. In PSP patients, only one subject (17%) showed a normal P3 component, three cases (50%) demonstrated low amplitude and normal latency P3, and two cases (33%) featured lack of normal P3 sequence. The P3 abnormalities in PSP patients were not related with dementia, but with low amplitude P3 being observed in 2 of 3 non-demented patients, and abolished P3 in a patient with only mild dementia. The result suggests that the P3 changes in PSP patients develop earlier than the cognitive dysfunction, and they are related to the underlying subcortical lesion rather than dementia.

Adult↗
PubMed1993

Postexposure prophylaxis of varicella in family contact by oral acyclovir.

OBJECTIVE: To determine whether varicella can be prevented by administration of oral acyclovir (ACV) during the incubation period of the disease. SUBJECTS AND METHODS: ACV (40 or 80 mg/kg daily in four divided doses) was given orally to 25 exposed infants and children for 7 days, starting 7 to 9 days after exposure from the index case in their families. Their clinical features were compared with those of 25 age-matched control subjects who had been exposed in their families but did not receive ACV. A fluorescent antibody to membrane antigen assay was used for determination of the antibody to varicella-zoster virus, and a nested polymerase chain reaction method was used for detection of viremia. RESULTS: Among the 25 who received ACV, 4 (16%) developed the disease and 1 (4%) had a fever. On the other hand, all of 25 control subjects developed the disease and 17 (68%) had a fever. The incidence of fever and the severity of skin rashes were significantly lower (P < .01) in the subjects who received oral ACV than in the control group. Seroconversion was observed in 84% of subjects who received ACV. In some cases, varicella-zoster virus DNA was detected by polymerase chain reaction amplification in peripheral blood mononuclear cells from blood drawn approximately 14 days after exposure. CONCLUSIONS: Varicella can be prevented or modified by administration of oral ACV late in the incubation period.

Acyclovir↗
PubMed1993

[Composite valve graft replacement for aortic root aneurysm or dissection].

Fifty four patients who had aneurysms (n = 35) or dissections (n = 19) associated with aortic regurgitation underwent the replacement of the ascending aorta and aortic valve by composite valve graft during 15-year period between September 1976 and December 1991. Of these, 49 (90.7%) patients had an annuloaortic ectasia and 26 (48.1%) had the Marfan syndrome. The methods of coronary artery reattachment to the graft were as follows: direct reattachment (original Bentall's technique) in 45 patients, aortic button technique (Carrel's patch technique) in 6, Cabrol's technique in 2 and Piehler's technique in 1 patients. Seven patients with a DeBakey type I dissection had concomitant replacement of the aortic arch with an aid of selective cerebral perfusion. The overall hospital mortality rate was 12.9%, and it has significantly decreased to 6.7% since we adopted a cold cardioplegia, preclotting the graft with albumin autoclave technique and coronary artery reattachment using conventional over-and-over and interrupted mattress sutures with pledgets during the last 10-years. The mean duration of follow-up period was 58.6 months. The actuarial survival rate at 10 years for all patients was 76.4%; for those with dissection, 78.4%; and for patients with Marfan syndrome, 70.4%. Reoperation for the prosthesis-related complications was necessary in only one patient, although operations on the remainder of aorta were required in 5 patients. Actuarial freedom from these operations at 10 years was 74.1%, but it was 69.3% for the subgroup with Marfan syndrome. The present data indicates that composite valve graft technique is an useful method for patients with aortic root aneurysms or dissections.

Adult↗
PubMed1992

Structural similarity of D-aminopeptidase to carboxypeptidase DD and beta-lactamases.

The gene for D-aminopeptidase (dap) has been isolated from the bacterium Ochrobactrum anthropi SCRC C1-38 [Asano, Y., Nakazawa, A., Kato, Y., & Kondo, K. (1989) J. Biol. Chem. 264, 14233-14239] and its nucleotide sequence determined. An expression plasmid pC138DP (4.5 kb) was constructed by placing the gene downstream of the lac promoter of pUC19. The amount of the enzyme in the cell-free extract of Escherichia coli JM109/pC138DP was elevated to 288,000 units/L of culture, which is about 3600-fold over that of O. anthropi SCRC C1-38. The enzyme comprised about 30% of the total extractable cellular protein. The gene consisted of an open reading frame of 1560 nucleotides which specifies a protein of Mr 57,257. The deduced amino acid sequence of the enzyme showed that it is related to carboxypeptidase DD, beta-lactamases, and penicillin-binding proteins. Seven mutants of the enzyme were generated by site-specific mutagenesis to explore the roles of the residues of interest, around the sequence Ser61-Xaa-Xaa-Lys64, where Xaa is any amino acid, since the identical sequences also appear in the penicillin-recognizing peptide hydrolases with Ser at the active sites. The mutant enzymes expressed in E. coli were purified to homogeneity and kinetically characterized. Replacements of the site at Ser61 and Lys64 yielded mutants showing significantly reduced Vmax values, while most of the Km values remained unchanged. Changes at Cys60, which is adjacent to the likely active center Ser61, to Ser and Gly resulted in the production of enzyme less sensitive to PCMB, with almost unaltered Vmax/Km values. The enzyme appears to be a serine peptidase rather than a thiol one. The inhibition by PCMB in the wild-type enzyme may have been caused by a formation of a mercaptide bond between Cys 60 and PCMB. Considering that D-aminopeptidase, carboxypeptidase DD (a penicillin-binding protein), and beta-lactamase have a common feature in recognizing peptides containing D-amino acid and that the former two catalyze transpeptidation reactions with substrates containing D-alanyl-D-alanine moieties, we propose that the enzyme is a new member of the "penicillin-recognizing enzymes". We showed that the enzyme is actually inhibited by beta-lactam compounds, such as 6-APA, 7-ACA, benzylpenicillin, and ampicillin, although they are not the substrate for the enzyme. The relationship between the primary structures and the reactions catalyzed by D-aminopeptidase and other serine hydrolases beta-lactamases and carboxypeptidase DD is discussed.(ABSTRACT TRUNCATED AT 400 WORDS)

Alcaligenes↗
PubMed1992

Comparative teratogenicity of di-n-butyltin diacetate with n-butyltin trichloride in rats.

Teratological tests were conducted on di-n-butyltin diacetate (DBTA), and n-butyltin trichloride (MBTC). Pregnant Wistar rats were treated orally with DBTA at doses of 0, 1.7, 5.0, 10.0, and 15.0 mg/kg/day or with MBTC at doses of 0, 50, 100, 200, and 400 mg/kg/day during days 7-17 of gestation. Cesarean sections were performed on day 20 of gestation. Thymic atrophy of the pregnant rats was observed in a dose-dependent manner by DBTA treatment. The incidence of dead or resorbed fetuses and total resorption fetuses increased at the highest dose of DBTA. The incidence of fetuses with external malformations, such as cleft mandible, cleft lower lip, ankyloglossia (tongue-tie) and schistoglossia (cleft tongue), increased in a dose-dependent manner by DBTA treatment. The incidence of fetuses with skeletal malformations such as anomaly of mandibular fixation, fused ribs, fused cervical vertebral arches and fused thoracic vertebral arches also increased at 10.0 and 15.0 mg/kg. However, MBTC, one of the main metabolites of di-n-butyltin, failed to show any evidence of tetatogenic activity at any doses tested. The results indicate that DBTA has potent teratogenic effects on rat fetuses, and DBTA is different from MBTC with respect to teratogenic effects.

Animals↗
PubMed1992

Partial portal arterialization for the prevention of massive liver necrosis following extended pancreatobiliary surgery: experience of two cases.

Massive liver necrosis, which is a severe and highly fatal complication after extended pancreatobiliary surgery, may occur due to an interruption of the hepatic arterial flow caused by such events as an excision of the hepatic artery invaded by cancer, a ligation of the postoperatively ruptured hepatic artery, or a thrombotic obstruction of the reconstructed hepatic artery. In order to improve this ischemic state of the liver, we have performed a partial arterialization of the portal vein by making an arteriovenous shunt at the mesenteric vascular branches in two cases. Although a sufficient pathophysiological investigation could not be fully conducted, partial portal arterialization was considered to be effective in one patient, while no clinically noticeable adverse effects were revealed in the other patient.

Arteriovenous Shunt, Surgical↗
PubMed1992

Prophylactic effect of bestatin on the onset of invasive mole--clinical and fundamental studies.

This study was performed to determine whether bestatin (Ubenimex) has clinical prophylactic effects on the onset of invasive mole and a direct inhibitory effect on the growth of hydatidiform molar cells. A total of 49 patients with hydatidiform mole treated at Nagoya University Hospital from 1984 to 1990 were randomly divided into two groups, a bestatin administered-group and a bestatin non-administered group. Patients in the bestatin group were given 30 mg of bestatin orally and daily for three months just after their molar deliveries. There was no significant difference in age, gravidity, parity and gestational weeks between the two groups. There was also no significant difference in the duration of human chorionic gonadotropin (hCG) negative conversion in patients without invasive mole between the two groups. However, the incidence of invasive mole in the bestatin group (2/25, 8%) was significantly lower than that of the non-bestatin group (7/24, 29.2%). Nevertheless, there was no significant difference between the two groups in such immunological parameters as PHA skin test, PPD skin test, PHA stimulation index (PHA-SI), white blood cell (WBC) count lymphocytes % per WBC, OKT 3% per lymphocytes, OKT 4% per lymphocytes, OKT4/OKT8 and Leu 11% per lymphocytes. In vitro studies were performed with primary cultured hydatidiform moles. The result was that bestatin inhibited the secretion of hCG and 3H-thymidine uptake of hydatidiform molar cells. Thus, a possibility was suggested that bestatin directly inhibits the growth of hydatidiform molar cells and prevents the onset of invasive mole.

Adolescent↗
PubMed1992

Electrophysiological follow-up of acute and chronic experimental allergic encephalomyelitis in the Lewis rat.

Cortical somatosensory evoked potentials (c-SEP) and flash visual evoked potentials (f-VEP) were serially recorded in acute monophasic and chronic relapsing experimental allergic encephalomyelitis (EAE) in the Lewis rat. In acute EAE, a significantly delayed latency and broadened peak of the c-SEP were observed corresponding to the clinical onset, and then returned to normal with the disappearance of clinical signs. In chronic EAE, the c-SEP showed the same changes as in acute EAE, also reflecting the first attack, remission and relapsing phase. However, chronic EAE, when paralysis had recovered in the relapsing phase, showed c-SEP abnormalities suggestive of subclinical active lesions. In contrast, the f-VEP showed no obvious abnormalities in acute or chronic EAE. These findings suggest that the c-SEP is an objective and sensitive index for detecting clinical and pathological changes in acute and chronic EAE in the Lewis rat.

Animals↗
PubMed1992

CD45 isoform expression on human neonatal T cells: expression and turnover of CD45 isoforms on neonatal versus adult T cells after activation.

Neonatal T cells are phenotypically similar to "naive" T cells from adult donors in the CD45 isoform expression. Despite the phenotypic similarity, large differences were found between neonatal and adult T cells when T cells were activated. After activation with PHA, adult CD45RA+ T cells began to express CD45RO and no loss of CD45RA expression had yet occurred at Day 3 post-stimulation. Three days after activation, CD45RA+ neonatal T cells also coexpressed CD45RO; however, in contrast to adult T cells, a marked loss of CD45RA was observed. We analyzed the rapid loss of CD45RA found in neonatal T cells. The de novo synthesis of CD45 isoforms in neonatal T cells was essentially the same as that in the adult T cells. Turnover of the CD45RA was very rapid in both resting adult and neonatal T cells. After activation with PHA, the turnover of CD45RA on adult T cells was decreased significantly, while the turnover of CD45RA on neonatal T cells was not changed after activation. Therefore, the regulation of CD45 isoform expression not only involves switches in alternative splicing, but also involves different regulation of turnover of these isoforms from the cell membrane.

Adult↗
PubMed1992

Signaling from LFA-1 contributes signal transduction through CD2 alternative pathway in T cell activation.

LFA-1, a member of the integrin family of molecules, is involved in mediating cellular adhesion in all phases of the immune response, playing a role in the interaction of helper T cells as well as in killing of target cells by both cytotoxic T cells and natural killer cells. We have developed a monoclonal antibody, anti-HVS6B6, which recognizes a functionally unique epitope of the LFA-1 molecule. Although this mAb itself was not mitogenic against T cells, it induced a strong proliferative response when added to T cells with submitogenic concentrations of anti-CD2 (anti-T11(2) and anti-T11(3)) mAbs. In contrast, other anti-LFA-1 mAbs (CD11a and CD18) suppressed this anti-CD2 mAb-induced T cell proliferation. Kinetic studies showed that anti-HVS6B6 acts on an early event in CD2-mediated T cell activation. Although T11(3)-epitope expression induced by anti-T11(2) mAb was not affected by treatment of cells with anti-HVS6B6, both Ca2+ influx and phosphatidylinositol turnover induced by anti-CD2 mAbs were markedly enhanced by the pretreatment of T cells with anti-HVS6B6 mAb. These results indicate that the LFA-1 mediating signal contributes to a very early phase of signal transduction during CD2-mediated T cell activation.

Antibodies, Monoclonal↗
PubMed1992

Expression of mumps virus glycoproteins in mammalian cells from cloned cDNAs: both F and HN proteins are required for cell fusion.

Two recombinant plasmids were constructed by inserting the cDNAs of either the fusion (F) or the hemagglutinin-neuraminidase (HN) protein genes of mumps virus into the pcDL-SR alpha expression vector. Both the F and the HN proteins expressed in COS7 cells transfected with their respective recombinant plasmids were indistinguishable in terms of electrophoretic mobility from their counterparts synthesized in mumps virus-infected cells. The F protein was cleaved and expressed on the cell surface, but uncleaved forms were also detected. The expressed HN protein was transported to the cell surface and adsorbed guinea pig erythrocytes. Syncytium formation was induced when COS7 cells were transfected with both recombinant plasmid DNAs together, but not with the recombinant plasmid only carrying the F gene. This observation indicates that cell fusion mediated by mumps virus requires both the F and the HN glycoproteins.

Animals↗
PubMed1992

Molecular cloning and sequence analysis of the mumps virus gene encoding the L protein and the trailer sequence.

We have cloned and determined the nucleotide sequences of the seventh gene of the Miyahara strain of mumps virus (MuV) encoding the L protein. The L gene is 6925 nucleotides in length and contains a single long open reading frame which is capable of coding for a protein of 2261 amino acids with a calculated molecular weight of 256,571 Da. The deduced amino acid sequence of the L protein of MuV showed significant homology with those of six other paramyxoviruses, human parainfluenza type 2 virus, Newcastle disease virus, Sendai virus, measles virus, human parainfluenza type 3 virus, and human respiratory syncytial virus. The predicted MuV L protein contained distinct elements thought to be essential for RNA polymerase activity. A noncoding sequence of 24 nucleotides downstream of the presumed polyadenylation site of the L gene showed significant complementarity with the leader sequence composed of 55 nucleotide at the 3' end of the genomic RNA.

Amino Acid Sequence↗
PubMed1992

Structural determination of gangliosides that bind to influenza A, B, and C viruses by an improved binding assay: strain-specific receptor epitopes in sialo-sugar chains.

An improved binding assay for detection of ganglioside receptors for influenza A, B, and C viruses was developed. In this system, the virions bound to gangliosides that were developed on a silica gel thin-layer plate were detected by mouse monoclonal antibody against viral hemagglutinin and peroxidase-conjugated anti-mouse immunoglobin. No hydrolysis of the gangliosides by viral receptor-destroying enzyme was detected in the present condition. The reactivity of the viruses to gangliosides depended on the amount of developed gangliosides (10 pmols-10 nmols), the molecular species of sialic acid, and their sugar sequences. Human influenza A (PR/8/34), B (Lee/40), and C (Ann Arbor/1/50) viruses bound different receptor epitopes of sialo-sugar chains of gangliosides. The A/PR/8 virus bound most effectively to Neu5Ac-containing lacto-series gangliosides carrying type I and type II sugar chains, followed by ganglio-series and hematoside-series gangliosides. The A/PR/8 virus weakly bound to Neu5Ac alpha 2,6lactotetraosylceramide [IV6(Neu5Ac)Lc4Cer] and Neu5Ac alpha 2,6paragloboside [IV6(Neu5Ac)nLc4Cer] carrying Neu5Ac alpha 2,6Gal sequence, although their Neu5Ac alpha 2,3Gal derivatives were the most potent gangliosides tested. B/Lee/40 bound restrictively to IV6(Neu5Ac)Lc4Cer and IV6(Neu5Ac)nLc4Cer, which carry Neu5Ac alpha 2,6Gal sequence, and type I and type II lacto-series sugar chain, respectively. C/Ann Arbor/1/50 reacted only with 9-O-Ac-Neu5Ac-carrying sugar chains in all the gangliosides tested. This method also allowed the microanalysis of receptor gangliosides of unknown samples. ESK cells, sensitive to the influenza A viruses infection, expressed several kinds of receptor active gangliosides, while those from ESK-R cells, resistant to the virus infection, were undetectable.

Binding Sites↗
PubMed1992

Protective effect of ren-shen-yang-rong-tang (Ninjin-youei-to) in mice with drug-induced leukopenia against Pseudomonas aeruginosa infection.

When 200 mg/kg of cyclophosphamide (CY) or 5-fluorouracil (5-FU) were given subcutaneously to mice, severe reduction of leukocyte numbers in the peripheral blood was observed on day 4 and from day 4 to day 8 after the treatment, respectively. Daily administration of ren-shen-yang-rong-tang (Japanese name: Ninjin-youei-to, NYT), (1 g/kg/day) and recombinant human granulocyte-colony stimulating factor (rhuG-CSF, 2 micrograms/mouse/day) either from day 0 to day 4 after treatment with CY or from day 0 to day 8 after treatment with 5-FU accelerated the recovery of peripheral leukocytes. Administration of NYT and rhuG-CSF inhibited decreases in the number of colony forming units in the spleen (CFU-S) in drug-treated mice. In mice infected intraperitoneally with a virulent strain of Pseudomonas aeruginosa 4 days and 8 days after treatment with CY and 5-FU, respectively, lethal doses were much lower (approximately 1/1000) than that in normal mice. Administration of NYT and rhuG-CSF to drug-treated mice inhibited the enhanced bacterial growth in the peritoneal cavity. Administration of NYT or rhuG-CSF to drug-treated mice enhanced the recovery of accumulation of leukocytes into the infected peritoneal cavity from their depressed state. Administration of NYT was more effective for improving the host resistance of 5-FU-treated mice than for improving that of CY-treated mice in contrast to rhuG-CSF which exhibited stronger effect in CY-treated mice than in 5-FU treated mice.

Animals↗
PubMed1992

Nasal antibody response to mumps virus after vaccination and natural infection.

Nasopharyngeal secretions and sera were collected during an epidemic of mumps in a semi-closed institution. None of the children who received live attenuated mumps vaccine 5 months previously developed any symptoms of mumps. Neutralizing and IgA antibodies against mumps virus were measured by the peroxidase-antiperoxidase method and the fluorescent antibody to membrane antigen method, respectively. The immune responses in nasopharyngeal secretions and serum were studied in four groups (apparently infected, non-apparently infected, non-infected and vaccinated). We found that IgA, which has neutralizing activity, was produced after vaccination as well as after natural infection. It is suggested that local antibody induced by vaccination may contribute to protection against the mumps virus.

Antibodies, Viral↗