Search PubMed⌕ Search

Biomedical subjects

E Yamamoto

Publications and source records attributed to E Yamamoto.

At least 127 records · Page 7Linked to original sources
PubMed1995

Factors affecting the occurrence of bacteremia associated with tooth extraction.

This study examined the factors that affect the occurrence of bacteremia associated with tooth extraction and the kinds of bacteria causing this bacteremia. Bacteremia was found in 132 (72.1%) of 183 patients who had one or more teeth extracted for various reasons. Bacteremia occurred more frequently when teeth were extracted because of inflammatory dental diseases. The occurrence of bacteremia also increased with the number of teeth extracted and the age of the patients. When the volume of blood lost during surgery was > 50 ml and the time required for the operation exceeded 100 min, the occurrence of bacteremia was also higher. Anaerobes were isolated from 104 (78.8%) of the 132 cases of bacteremia. Of the 187 isolates obtained, three (1.6%) were aerobes, 51 (27.3%) were facultative anaerobes (including microaerophils), and 133 (71.1%) were anaerobes. Among facultative anaerobes and microaerophils, the most frequently isolated bacterial genera were Lactobacillus (n = 15), Streptococcus (n = 13), and Staphylococcus (n = 12); and among anaerobes, Eubacterium (n = 40), Peptostreptococcus (n = 40), and Propionibacterium (n = 20).

Adolescent↗
PubMed1995

The slow progression of hepatic fibrosis in intrahepatic cholestasis as compared with extrahepatic biliary atresia.

It has been shown that the progression of hepatic fibrosis in intrahepatic cholestasis (IHC) is not so prominent as in extrahepatic biliary atresia (EHBA), and that the biosynthetic activity of collagen increases along with the fibrotic disease process. We conducted immunohistochemical and ultrastructural studies on the distribution of collagen types III and IV and of alpha-actinin in the smooth musculature in liver specimens obtained from 4 patients with IHC and 14 patients with EHBA in liver transplantation from living related donors (LRLT). A recently developed sandwich enzyme immunoassay (EIA) was used to determine serum concentrations of type IV collagen, laminin and prolyl 4-hydroxylase (PH) in the patients before and after LRLT. Pathological study showed that the excessive deposition of type IV collagen in the perisinusoidal walls resulted in a clearly developed basal membrane beneath the sinusoidal endothelial cells, so-called sinusoidal capillarization. In the fibrous septa of IHC, fibrogenesis was apparently lower than in EHBA, since collagen deposition and myofibroblast proliferation were not so prominent compared to EHBA. Serum type IV collagen, laminin and PH increased in IHC, although not so markedly as in EHBA, and returned to normal within 5 weeks after successful LRLT. In conclusion, it is suggested that an increased level of serum type IV collagen reflects the de novo synthesis of basal membrane components, and that the determination of their serum levels by EIA can be utilized for the differentiation of the specific fibrogenic activity in each disease, and for monitoring patients before and after liver transplantation.

Actinin↗
PubMed1995

The frequency of 4977 base pair deletion of mitochondrial DNA in various types of liver disease and in normal liver.

Using a polymerase chain reaction (PCR) method, we tested for the hepatic mitochondrial DNA (mtDNA) deletion in 40 hepatic tumors (28 hepatocellular carcinomas [HCCs], 9 other malignant tumors, and 3 benign tumors) and in the livers of 71 patients, including 16 pediatric patients with end-stage liver disease who underwent living related donor liver transplantation and 16 liver donors. A 4977 base pair (bp) deletion of mtDNA was detected in 36 of 55 specimens of non-tumor portions of adult liver (65.5%). However, none of the specimens obtained from cirrhotic livers of the 16 pediatric patients younger than 13 years of age had the 4977 bp deletion. The frequency of mtDNA deletion was significantly decreased compared with normal liver in HCCs (7 of 28) and other malignant liver tumors (2 of 9). The frequency of this deletion was unrelated to the presence of liver cirrhosis, patient's gender, hepatitis B virus surface antigen status, and hepatitis C virus antibody status.

Adolescent↗
PubMed1994

A matrix metalloproteinase expressed on the surface of invasive tumour cells.

Gelatinase A (type-IV collagenase; M(r) 72,000) is produced by tumour stroma cells and is believed to be crucial for their invasion and metastasis, acting by degrading extracellular matrix macro-molecules such as type IV collagen. An inactive precursor of gelatinase A (pro-gelatinase A) is secreted and activated in invasive tumour tissue as a result of proteolysis which is mediated by a fraction of tumour cell membrane that is sensitive to metalloproteinase inhibitors. Here we report the cloning of the complementary DNA encoding a new matrix metalloproteinase with a potential transmembrane domain. Expression of the gene product on the cell surface induces specific activation of pro-gelatinase A in vitro and enhances cellular invasion of the reconstituted basement membrane. Tumour cells of invasive lung carcinomas, which contain activated forms of gelatinase A, were found to express the transcript and the gene product. The new metalloproteinase may thus trigger invasion by tumour cells by activating pro-gelatinase A on the tumour cell surface.

3T3 Cells↗
PubMed1994

Methicillin-resistant Staphylococcus aureus endocarditis following patch closure of a ventricular septal defect: report of a case.

We report herein the case of a 5-month-old infant who, after developing methicillin-resistant Staphylococcus aureus (MRSA) endocarditis following patch closure of a ventricular septal defect (VSD), was successfully treated by replacement of the Dacron patch with an autogenous pericardial patch. Initially, a large perimembranous VSD was repaired with a Dacron patch and after an uneventful recovery of 1 week, he began to spike intermittent fevers from 38 degrees C to 39 degrees C. Two blood cultures grew MRSA and a two-dimensional echocardiogram performed 16 days after surgery showed an irregular mass attached to the right ventricular aspect of the Dacron patch. At reoperation, a large vegetation attached to the Dacron patch was confirmed, but there was no patch dehiscence. Following removal of the patch, the VSD was repaired with an autogenous pericardial patch, soon after which the fever rapidly subsided. Imipenem, 125 mg every 6 h, and fosfomycin, 300 mg every 6 h, were administered for a total of 24 days after reoperation. The child remains well 12 months after his second operation.

Endocarditis, Bacterial↗
PubMed1994

Infectious complications in living related liver transplantation.

During the last 31 months, 50 children between 3 months and 15 years of age have undergone living related liver transplantation (LRLT) for end-stage liver diseases (39 biliary atresia, 2 Budd-Chiari syndrome, 2 progressive intrahepatic cholestasis, 3 liver cirrhosis, 1 Wilson disease, 1 protoporphyria, 1 tyrosinemia, and 1 fulminant hepatitis). Combined FK-506 and low-dose steroids were routinely used for immunosuppression. There were seven deaths, two of which were related to infection (Candida pneumonia and Epstein-Barr virus [EBV]-associated lymphoproliferative syndrome [LPS]). Five patients had a bacterial infection, all of which were associated with surgical complications. Three patients had Candida infection, all of which were malnourished, had biliary atresia, and had been managed with prolonged antibiotics against obstinate ascending cholangitis. There were 14 symptomatic viral infections (1 herpes simplex virus, 1 herpes zoster virus, 5 cytomegalovirus [CMV], 6 EBV, and 1 EBV-associated LPS). Three of the five CMV infections appeared in patients whose graft was ABO-incompatible, who were managed with prophylactic OKT-3. Most of the viral infections (except 1 EBV-associated LPS) were minor and were treated successfully. The low incidence and successful treatment of CMV infection are related to the high compatibility and low incidence of allograft rejection in LRLT. Bacterial and fungal infections can be decreased by greater refinement of surgical technique and more aggressive preoperative management. Treatment of EBV infection is still an unsolved problem.

Adolescent↗
PubMed1994

Living related liver transplantation in children.

We reviewed 37 living related liver transplantations (LRLT) performed by our department during the last 27 months on children with end-stage liver disease. The patients were 15 boys and 22 girls aged 7 months to 15 years with biliary atresia (27), cryptogenic cirrhosis (3), Budd-Chiari syndrome (2), progressive intrahepatic cholestasis (2), protoporphyria (1), Wilson's disease (1), and fulminant hepatitis (1). The donors were 14 fathers and 23 mothers. Grafts were made from the left lateral segment (19), left lateral segment with partial S4 (11), left lobe (6), and right lobe (1). After graft harvesting all donors resumed normal liver function and normal life. The recipient underwent total hepatectomy with preservation of the inferior vena cava. FK506 and low-dose steroids were used for immunosuppression. The survival rate was 90% (27/30) in elective cases and 57% (4/7) in emergency cases. Six recipients had functioning grafts but died of extrahepatic complications. Hepatic vein stenosis occurred in 3 cases at 3 months after LRLT and was successfully treated by balloon dilatation. Portal vein stenosis occurred in 1 case at 8 months after LRLT and was also safely dilated. We incurred no hepatic artery thrombosis after introducing microsurgery techniques. Among 12 viral, 5 bacterial, and 3 fungal postoperative infections, 1 Candida pneumonia and 1 EBV-associated lymphoma were lethal. Three patients with ABO-blood group compatible grafts and one with an incompatible graft developed acute rejection, which was controlled in evey case by steroid bolus and/or increasing the dose of FK506. There were no definite episodes of rejection in ABO-identical cases. Children with moderate growth retardation (> or = -1.5 SD of normal growth) caught up in growth soon after LRLT, but those with severe retardation (<-1.5 SD) were slow to attain age-normal height. Appropriate timing, meticulous surgical procedures, and comprehensive management of complications are crucial for successful outcome with LRLT. LRLT is a promising option for alleviating the shortage of livers for pediatric transplantation and may be regarded as an independent modality to supplement cadaver donation.

Acute Disease↗
PubMed1994

Mutational analysis of the Sar1 protein, a small GTPase which is essential for vesicular transport from the endoplasmic reticulum.

SAR1 encodes a 21-kDa GTPase, which is required for vesicle formation from the endoplasmic reticulum in yeast. Although it belongs to the expanding small GTPase superfamily, there are interesting structural features that are unique to the Sar1 protein. We performed a site-directed mutational study to identify the amino acid residues that are essential for the Sar1p function. Among seven mutants we constructed, four are functionless by themselves, while two confer temperature sensitivity to cells. When the mutant proteins are overproduced in wild-type cells, all of these six show a dominant negative effect on cell growth. The replacement by serine of the only cysteine residue present in Sar1p caused no significant change in the growth phenotype. These findings are not only important for analyzing the mechanism of the Sar1p action in yeast, but will also be very useful for studying the function of Sar1p counterparts in higher eukaryotes.

Amino Acid Sequence↗
PubMed1994

Long-term use of FK 506 in living related liver transplantation.

FK 506 (Tacrolimus) was used with steroids to treat 61 pediatric patients who received living related partial liver transplantation. Fifty-two recipients survived and 9 died between 6 months and 3 years after transplantation. In the surviving patients, oral doses of Tacrolimus were tapered from 0.298 +/- 0.277 mg/kg daily at 1 month after transplantation to 0.078 +/- 0.054 at 24 months after transplantation. The 12 h trough levels of Tacrolimus were 12.6 +/- 7.1 ng/ml and 4.1 +/- 2.4 at 1 and 24 months after transplantation, respectively. The percentage of recipients free from steroids was 77%, 97%, and 94% at 6, 12, and 24 months after transplantation, respectively. Liver allograft rejection was encountered in seven recipients, five of whom were treated by steroid pulse therapy and a dose increase of Tacrolimus; the remaining two required OKT3. However, there was no episode of rejection that required retransplantation. Infectious complications encountered in 34 patients included 12 bacterial, 3 fungal, and 19 viral infections. Two recipients died one of fungal pneumonia and one of Epstein-Barr virus-associated lymphoproliferative disorder. Regarding adverse reactions of Tacrolimus, hypertension was observed in 28 patients, diabetes mellitus in 3, pancreatitis in 3, convulsion in 1, tremor in 12, itching in 5, and pigmentation in the oral mucosa in 2. Slightly increased values of creatinine were observed in most of the patients; however, an abnormal increase of serum of serum creatinine (> 1.0 mg/dl) was confined to the complicated cases. Improvement of somatic growth was observed in 21 patients (62%) and 13 (75%) at 12 and 24 months after transplantation, respectively. The long-term use of Tacrolimus is highly effective in terms of its immunosuppressive potential and reduced adverse reaction. Steady growth development can be expected in pediatric recipients free from steroids.

Adolescent↗
PubMed1994

[An epidemiologic research design using the Annual of the Pathological Autopsy Cases in Japan].

Epidemiologic research designs using the Annual of the Pathological Autopsy Cases in Japan (APAC hereinafter) are discussed in this paper. The APAC data base has been recommended for use in epidemiologic research. However, it has not often been utilized for such research, even though it covers all pathological autopsy cases in Japan, perhaps because of different sampling proportions of each disease and because of the dead control series in APAC. First, we present epidemiologic measures in using the APAC. We show that the data base can be treated as a case-control design and that the magnitude of the exposure effect should be estimated by an odds ratio. Next, selection bias and information bias in using the APAC are discussed. The independence of the control series from the exposure is important in the determination of the control disease. Because this design is based on internal comparison, non-differential misclassification should be stressed more than differential misclassification.

Autopsy↗
PubMed1994

Statistical methods for the beta-binomial model in teratology.

The beta-binomial model is widely used for analyzing teratological data involving littermates. Recent developments in statistical analyses of teratological data are briefly reviewed with emphasis on the model. For statistical inference of the parameters in the beta-binomial distribution, separation of the likelihood introduces an likelihood inference. This leads to reducing biases of estimators and also to improving accuracy of empirical significance levels of tests. Separate inference of the parameters can be conducted in a unified way.

Animals↗
PubMed1994

Audiometry database system using a local area network.

We linked several audiometers to a personal computer to implement a standard pure-tone audiometric database system using a local area network (LAN). The efficiency of data entry and retrieval was increased by taking advantage of a relational database. The following five programs were developed: automatic incorporation of hearing test data program, audiogram retrieval and display program, patient information incorporation program, data transmission program through LAN, and evaluation of results of tympanoplasty. Data obtained over ten years or more can be rapidly stored and retrieved in this system, making it easier to evaluate the patient's hearing after tympanoplasty.

Audiometry, Pure-Tone↗
PubMed1994

[Advance of magnetic resonance spectroscopic imaging (MRSI) techniques].

Magnetic resonance spectroscopic imaging (MRSI) can provide density images of various metabolites in the human body, in vivo, by utilizing chemical shift. This technique has received attention as a new method for analyzing the diseased state, via metabolism. It increases the accuracy of diagnosis and provides hope for early diagnosis of brain disease. However, because a measurement time of more than ten minutes to one hour is required for imaging, it has been difficult to use MRSI techniques for clinical diagnosis. Improved techniques for high-speed imaging have recently been developed. This review describes the recent advances in this field.

Animals↗
PubMed1993

Experience with FK506 in living-related liver transplantation.

The new immunosuppressive agent FK506 was used with steroids to treat 22 pediatric patients who received living-related partial liver transplantation. Seventeen recipients survived and 5 died between one and 16 months after transplantation. Three of the 5 patients who died had required intensive care preoperatively. Autopsy findings showed no evidence of rejection. There was no episode of rejection that required retransplantation in any of the patients. Liver allograft dysfunction, which was suspected to be a rejection response, was encountered in 2 recipients with ABO-nonidentical but compatible grafts. However, their clinical and biochemical findings were ameliorated upon steroid pulse therapy or upon augmented FK506 administration without additional potent immunosuppressive agents. Steroid treatment has been discontinued in all surviving patients at 1-9 months after transplantation. Infectious complications encountered in 9 patients included 2 bacterial, 5 viral, and 2 fungal infections. One recipient died of fungal pneumonia. Abnormal increase of serum creatinine level was confined to the complicated patients. Hypertension was a temporary adverse reaction in the early postoperative period, and only one patient needed an antihypertensive drug at 2 months after transplantation. Acute pancreatitis with hyperamylasemia was observed in one patient who was treated successfully with reduction of FK506 administration. Tremor was observed in 8 patients, itching in 4, insomnia in 2, and vomiting in one. Hirsutism, gingival hypertrophy, and lymphoma were not observed. FK506 was highly effective in living-related partial liver transplantation not only in terms of immunosuppressive potential but also because it produced fewer adverse effects.

Adolescent↗
PubMed1993

The expression of invasive behavior of differentiated squamous carcinoma cell line evaluated by an in vitro invasion model.

In order to elucidate the factors contributory to the expression of invasiveness of oral squamous cell carcinoma, we conducted biochemical and morphological comparisons of well differentiated squamous carcinoma cell line OSC-19 (oral squamous cell carcinoma) and undifferentiated carcinoma cell line KB, both cultured on 3T3 cell-embedded collagen gel (in vitro invasion model). OSC-19 cells invaded 3T3 cell-embedded collagen gel, while KB cells and OSC-19 cells on 3T3 cell-free gel matrix were less invasive. Cultured OSC-19 cells were characterized by lower proliferating activity, lower secretion of laminin and higher secretion of fibronectin than those of KB cells. Although the basement membrane with deposition of laminin and type IV collagen was formed, it was discontinuous at the invasion front. Gelatin zymography and western blotting showed matrix metalloproteinases (MMP), i.e., 72 kDa gelatinase (MMP-2) and 92 kDa gelatinase (MMP-9). Gelatinolytic activity was assayed, and was higher in OSC-19 cells than in KB cells or OSC-19 cells of the 3T3 cell-free model. By immunohistochemical analysis, MMP-2-positive cells were found scattered in both cell lines without any preferential localization, and the positivity for MMP-9 was localized in the invasion front of OSC-19 cells. These results strongly suggest that the invasiveness of squamous cell carcinoma is well correlated with cell-matrix adhesion by fibronectin and with focal elaboration of metalloproteinases, especially MMP-9, which play a major role in degrading the extracellular matrix components.

3T3 Cells↗
PubMed1993

Molecular sorting in polarized and non-polarized cells: common problems, common solutions.

We have been interested in determining how epithelial cells generate and maintain their characteristically polarized distributions of membrane proteins. Our efforts to date strongly indicate that the polarized transport in MDCK cells may be due to a set of discrete targeting determinants often found on a membrane protein's cytoplasmic domain. Surprisingly, these determinants are widely distributed and are not specific to proteins expressed in polarized cells. They also appear to function in controlling polarized transport along both the biosynthetic and the endocytic (or transcytotic) pathways. Signals for basolateral transport have been characterized and, like the cytoplasmic domain signal used by plasma membrane receptors for accumulation at clathrin-coated pits, they often involve a critical tyrosine residue. Although the basolateral and coated pit signals may also be co-linear, they are not identical. The basolateral and apical transport determinants are also hierarchically arranged. Although a single protein may contain one or more signals specifying basolateral transport, inactivation of these signals appears to reveal a determinant that directs efficient apical transport. Given that the sequence determinants responsible for polarized transport are not restricted to epithelial cells and are related to determinants commonly utilized in all cells, it is possible that non-polarized cells contain cognate apical and basolateral pathways that are responsible for 'constitutive' transport from the Golgi to the plasma membrane. The presence of two cognate pathways might confer a high degree of plasticity to pre-differentiated cells, allowing them rapidly to begin assuming a polarized phenotype in response to extracellular stimuli without requiring the synthesis of epithelial cell-specific transport machinery.

Amino Acid Sequence↗
PubMed1993

Development of the vestibular aqueduct in Menière's disease.

The external aperture width of the vestibular aqueduct was measured in living subjects of various ages, with normal and diseased ears. Measurements were made from 3-dimensional reconstruction of CT images, and the developmental process was studied. The following results were obtained. i) In Menière's disease the external aperture was hypoplastic and its width significantly smaller than that in normal individuals and those with chronic otitis media, including children. ii) There were no significant differences between normal ears and ears with chronic otitis media in either adults or children. The development of external aperture was completed in childhood. iii) In Menière's disease, hypoplasia evidently begins before childhood, which suggests that congenital factors are involved in the pathology of this disease.

Adolescent↗