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Biomedical subjects

Y Yamazaki

Publications and source records attributed to Y Yamazaki.

At least 253 records · Page 14Linked to original sources
PubMed1998

Severe chronic active Epstein-Barr virus infection accompanied by virus-associated hemophagocytic syndrome, cerebellar ataxia and encephalitis.

We present a rare case of chronic active Epstein-Barr virus (EBV) infection showing various clinical outcomes. A 26-year-old man was admitted to our hospital due to persistent fever and dyspnea. Serologic response of the patient to EBV indicated chronic active infection. He showed pleuritis, parotitis, chronic hepatic dysfunction, disseminated intravascular coagulation, virus associated hemophaghocytic syndrome, acute rhabdomyolysis, acute renal failure, acute cerebellar ataxia, encephalitis and multiple brain abscesses. None of acyclovir, gancyclovir, prednisolone or interleukin-2 was effectual to abolish those abnormalities. This is the first report of transient cerebellar ataxia which aggravated to panencephalitis associated with chronic EBV infection.

Acute Kidney Injury↗
PubMed1998

Full-length sequence analysis of the vacA gene from cytotoxic and noncytotoxic Helicobacter pylori.

Some clinical isolates of Helicobacter pylori fail to express vacuolating cytotoxin, despite possessing a copy of the vacA gene on the chromosome. To gain insight into the differences between vacA from cytotoxic and noncytotoxic strains, the vacA open-reading frames from 16 cytotoxic and 22 noncytotoxic strains were sequenced. Mutations that cause truncation of VacA in 11 of 22 noncytotoxic strains were identified, including internal duplication, large deletion, 1-bp insertion, and non-sense mutations. In contrast, none of the 16 cytotoxic strains had any truncation of VacA. Four cytotoxic strains had inserted sequences downstream of vacA. Three were mini-IS605, and the other was a putative rfaJ gene that encodes lipopolysaccharide glucosyltransferase. The rfaJ gene identified in this study had a poly(C) tract, resulting in premature termination of the gene product. The phylogenetic tree based on the vacA open-reading frame indicated that two different H. pylori lineages are circulating in Japan and the West.

Bacterial Proteins↗
PubMed1998

In vivo gene transfer to mouse spermatogenic cells by deoxyribonucleic acid injection into seminiferous tubules and subsequent electroporation.

An in vivo gene transfer technique for living mouse testes was used to develop a novel transient expression assay system for transcriptional regulatory elements of spermatogenic specific genes. The combination of DNA injection into seminiferous tubules and subsequent in vivo electroporation resulted in an efficient and convenient assay system for gene expression during spermatogenesis. The transfer of the firefly luciferase reporting gene driven by the Protamine-1 (Prm-1) enhancer region revealed a significant increase in the activity of the reporter enzyme. Histochemical studies of the transfer of the lacZ gene driven by the Prm-1 enhancer showed specific lacZ expression only in haploid spermatid cells in adult testes, corresponding with the expression pattern of endogenous Prm-1. We were able to detect long-lasting transgene expression in the transfected spermatogenic cells. A group of spermatogenic differentiating cells maintained the transfected lacZ expression after more than 2 mo of transfection, suggesting that spermatogenic stem cells and/or spermatogonia could also incorporate foreign DNA and that the transgene could be transmitted to the progenitor cells derived from a transfected proliferating germ cell.

Animals↗
PubMed1998

Use of the protective antigen of Erysipelothrix rhusiopathiae in the enzyme-linked immunosorbent assay and latex agglutination.

To establish a safe and convenient serodiagnostic method for swine erysipelas, a purified protective protein antigen of Erysipelothrix rhusiopathiae, which included a large amount of protective protein (64 kDa protein), was used for enzyme-linked immunosorbent assay (ELISA) and the latex agglutination (LA) test. In the ELISA, the antisera to four different serovars (1a, 2, 5 and 20) of E. rhusiopathiae exhibit a positive reaction, while antisera to other species of bacteria (Listeria monocytogenes, Staphylococcus aureus, Streptococcus suis, Rhodococcus equi and Corynebacterium pseudotuberculosis) exhibit a negative reaction. In the LA test, the antisera to three different serovars (1a, 2 and 5) of E. rhusiopathiae reacted with P64-sensitized latex beads, while the antiserum to serovar 20 (2553 strain) did not. Moreover, the antisera to other species of bacteria (Listeria monocytogenes, Staphylococcus aureus, Streptococcus suis, Rhodococcus equi and Corynebacterium pseudotuberculosis) did not in this test. Comparing the results of the growth agglutination (GA), ELISA and LA tests of 284 swine sera, there was a high degree of correlation among the results. The detection of anti-E. rhusiopathiae antibodies in the GA, ELISA and LA tests were compared using sera from pigs immunized with P64, alkaline extract (AE) and live-cell vaccine (LV). In all three tests, anti-E. rhusiopathiae antibodies could be detected 1 week after immunization. The serum antibody titre as determined by the LA test increased moderately, as did that by the GA test, while that determined by ELISA increased rapidly. These results suggested that ELISA could be used to monitor changes in anti-E. rhusiopathiae antibody titre and the LA test could be used in the screening test for swine erysipelas.

Animals↗
PubMed1998

Renal transplantation into augmented bladders.

BACKGROUND: Urinary bladder augmentation is gaining popularity for the treatment of dysfunctional bladders in renal transplant patients. Although reported cases of adult and pediatric transplants into the augmented bladder have been favorable, the potential risk of urinary tract infection and graft failure under immunosuppression is still disputable. We report our experiences with 4 patients who underwent renal transplantation into an augmented bladder. METHODS: Between 1971 and 1996, 1275 renal transplants were performed at our institution. Of these transplants, 4 patients underwent renal transplantation into an augmented urinary bladder. Augmentation cystoplasty was performed before transplantation in 3 patients and 7 years after transplantation in the other patient. The bladder was augmented with an ileal segment in 3 patients and a ureter in the fourth patient. Graft function was assessed by the serum creatinine level. Fluorocystometrograms were performed in all patients at fixed intervals. RESULTS: Posttransplant renal function was satisfactory overall and no patient exhibited proteinuria. All patients except 1 acquired a large capacity low pressure bladder and remained continent with clean intermittent catheterization. One patient who underwent ureterocystoplasty is still incontinent because of his relatively small bladder capacity. Posttransplant pyelonephritis was documented in 3 patients during the follow-up period, but no other complications were observed. CONCLUSIONS: Our study demonstrates that renal transplantation into extensively reconstructed bladders can be safely performed with good success. Although urinary tract infection is a major consideration, we recommend pretransplant reconstruction not only to preserve graft function, but also to achieve urinary continence.

Adult↗
PubMed1998

Phylogenetic analysis of the entire genome of influenza A (H3N2) viruses from Japan: evidence for genetic reassortment of the six internal genes.

Nucleotide sequences of all eight RNA segments of 10 human H3N2 influenza viruses isolated during a 5-year period from 1993 to 1997 were determined and analyzed phylogenetically in order to define the evolutionary pathways of all genes in a parallel fashion. It was evident that the hemagglutinin and neuraminidase genes of these viruses evolved essentially in a single lineage and that amino acid changes accumulated sequentially with respect to time. In contrast, amino acid differences in the internal proteins were erratic and did not accumulate over time. Parallel analysis of the phylogenetic patterns of all genes revealed that the evolutionary pathways of the six internal genes were not linked to the surface glycoproteins. Genes coding for the basic polymerase-1, nucleoprotein, and matrix proteins of 1997 isolates were closest phylogenetically to those of earlier isolates of 1993 and 1994. Furthermore, all six internal genes of four viruses isolated in the 1995 epidemic season consistently divided into two distinct branch clusters, and two 1995 isolates contained PB2 genes apparently originating from those of viruses before 1993. It was apparent that the lack of correlation between the topologies of the phylogenetic trees of the genes coding for the surface glycoproteins and internal proteins was a reflection of genetic reassortment among human H3N2 viruses. This is the first evidence demonstrating the occurrence of genetic reassortment involving the internal genes of human H3N2 viruses. Furthermore, internal protein variability coincided with marked increases in the activity of H3N2 viruses in 1995 and 1997.

Amino Acid Sequence↗
PubMed1998

Pulmonary infection with Mycobacterium avium-intracellulare leads to air trapping distal to the small airways.

To clarify the structure and function of the airways in Mycobacterium avium-intracellulare (MAI) infection, we performed pulmonary function tests and high-resolution computed tomography (HRCT) of the thorax in female patients 61 +/- 9 yr of age (n = 12) with pulmonary MAI infection without predisposing lung disease and compared their data with those of normal female volunteers 54 +/- 8 yr of age (n = 9). We calculated the E/I ratio, i.e., the average ratio of HRCT number at full expiration to that at full inspiration, as an index for the evaluation of air trapping distal to the small airways. Patients showed significant increases in residual volume and slope of phase III (DeltaN2) of the single-breath nitrogen test, and significant decreases in flow at 50 and 25% of FVC, suggesting hyperinflation and obstruction of the small airways. HRCT of patients revealed the small nodules and ectasis of bronchioles and small bronchi located mainly in segments (S) S2, S3, S4, and S5. The E/I ratio was significantly elevated in patients, and especially higher in the upper lung field than in the lower lung field, suggesting air trapping distal to the small airways. The difference of E/I ratio between the upper and lower field is probably related to the segmental distribution of CT abnormalities. These findings suggest that MAI infection can lead to air trapping distal to the small airways.

Airway Obstruction↗
PubMed1998

Analysis of BAL fluid in M. avium-intracellulare infection in individuals without predisposing lung disease.

The purpose of this study was to investigate the characteristics of pulmonary inflammation caused by Mycobacterium avium-intracellulare (MAI) in individuals with neither predisposing lung disease nor immunodeficiency. We reviewed the records of 20 patients with pulmonary MAI infection (including 19 female patients) whose past history and previous chest radiographs revealed no predisposing lung disease. We analysed the bronchoalveolar lavage fluid (BALF) from these 20 patients and from six normal female controls. The BALF was recovered directly from the relevant segment that was identified with chest-computed tomography. The BALF cell profiles showed significantly elevated counts for total cells, lymphocytes and neutrophils, but the macrophage cell count was not elevated. The CD4+ lymphocyte count and CD4+/CD8+ ratio were significantly increased compared with those in the controls. The lymphocytes demonstrated phenotypical evidence of activation, with increased expression of human leukocyte antigen-D-related antigen (HLA-DR). The tumour necrosis factor-alpha, interleukin (IL)-1beta, IL-6 and IL-8 concentrations were significantly increased. The neutrophil elastase concentration was also increased, and it was significantly correlated with the neutrophil cell count in the BALF. These findings suggest that the increased counts of activated CD4+ lymphocytes and neutrophils and the elevated concentrations of proinflammatory cytokines and neutrophil elastase appear to be common characteristics in Mycobacterium avium-intracellulare infection.

Bronchoalveolar Lavage Fluid↗
PubMed1998

Clinical and neuroimaging features of Chiari type I malformations with and without associated syringomyelia.

The clinical and neuroimaging characteristics of 22 consecutive patients with Chiari type I malformations were evaluated to investigate the pathogenesis of syrinx formation. All patients underwent magnetic resonance imaging and x-ray tomography before surgery. The electric manometric Queckenstedt test was performed on 16 patients pre- and postoperatively. Syringomyelia was present in 17 patients and absent in five patients. All patients without syringomyelia suffered from foramen magnum compression syndrome, with a wider basal angle, more acute clivo-axial angle, shorter clivus, and more prominent tonsillar ectopia than patients with syringomyelia. Low brain stem position, basilar impression, and beaking of the cervicomedullary junction were also more prominent in patients without syringomyelia. Marked to complete block with the neck in flexed position by Queckenstedt test was present in all patients except one. Patients with Chiari malformation not associated with syringomyelia have more pronounced compression of the brain stem at the foramen magnum. Therefore, despite a block of the cerebrospinal fluid pathway at the foramen magnum, syrinx formation may be prevented by severe compression.

Adolescent↗
PubMed1998

Histochemical determination of stereoselectivity of esterases in normal pancreas and pancreatic tubular adenocarcinoma of hamsters.

Esterases in normal hamster pancreas and pancreatic tubular adenocarcinoma of ductal origin induced by N-nitrosobis(2-oxopropyl)amine were stained in cryostat sections with mixtures of a diazonium salt (fast blue RR) and with each of the enantiomers of alpha-naphthyl N-methoxycarbonylalaninate, N-methoxycarbonylvalinate, and N-acetylprolinate. Azo coupling of alpha-naphthol formed by enzymatic hydrolysis with the diazonium salt gives an azo dye that indicates the presence and amount of the enzyme activity in situ. Comparison between the color intensities obtained with each of the enantiomers of a chiral alpha-naphthyl ester shows the stereoselectivity, or enantiomeric preference, of the enzyme. Esterases in acinar cells of the normal pancreas showed slight stereoselectivity for N-methoxycarbonylalaninate, while esterases in fat cells scattered throughout the exocrine pancreas showed high stereoselectivity for (R)-N-acetylprolinate. These esterase activities were not found in the tumor, but another prominent esterase activity with high stereoselectivity for (S)-N-methoxycarbonylvalinate was found. Similar results were obtained by staining after polyacrylamide gel electrophoresis showing that the bands of esterases in the adenocarcinoma stained only with the S enantiomer of the N-methoxycarbonylvalinate. The present method is a valuable tool for designing anticancer prodrugs that are activated by tumor-specific esterases.

Adenocarcinoma↗
PubMed1998

[Giant retroperitoneal hematoma in a patient with von Recklinghausen's disease].

A 51-year-old male of von Recklinghausen's disease presented with huge retroperitoneal hematoma caused by spontaneous arterial rupture. He died of uncontrollable hemorrhage during the operation. Gross appearance of aorta, renal artery, celiac artery, pulmonary artery and lumbar artery were extremely fragile, and there was a complete rupture between aorta and lumbar artery. On the microscopic examination, significant medial dysplasia were demonstrated in these arteries. Arterial stenosis is well-known vascular complication in von Recklinghausen's disease. Spontaneous rupture of major artery, however, has been extremely uncommon. This is the 26th case reported in the world literature, and 21th case in the Japanese literature.

Aortic Rupture↗
PubMed1998

[Postoperative hypoxia and hyperfibrinolysis in patients after total knee replacement].

It was revealed that postoperative hypoxia had occurred frequently in patients after total knee replacement (TKR) in our preliminary study. Since we speculated that pulmonary embolism was the cause of the hypoxia, we investigated the relationship between PaO2 and D-dimer in patients after TKR and high tibial osteotomy (HTO). A total of 13 patients with the diagnosis of osteoarthritis were studied. Ten patients underwent TKR and three received HTO under subarachnoid block. Arterial oxygen tension and D-dimer were unchanged in patients who had undergone HTO. Even on the 5th postoperative day, five of the ten patients after TKR revealed a decrease in oxygen tension by more than 10% compared with the preoperative control (hypoxia group). In the other patients after TKR, a decrease of oxygen tension on the 5th postoperative day was under 10% (non-hypoxia group). There was a positive correlation between a decrease of PaO2 and a value of D-dimer in all of the patients who had undergone TKR and HTO. Although no patient developed dyspnea clinically, one patient in hypoxia group was diagnosed as pulmonary embolism in the scintigram. It is likely that pulmonary embolism is the cause of postoperative hypoxia in patients after TKR.

Aged↗
PubMed1998

[Traumatic aortic regurgitation: report of two surgical cases].

Two successful surgical cases with aortic regurgitation due to blunt trauma are reported. Case 1: A 48-year-old female was transferred to our hospital after a traffic accident. She was intubated and mechanically ventilated. Twelve days later, echocardiography demonstrated massive aortic regurgitation. The next day, aortic valve replacement was performed using a 21 mm SJM mechanical valve. The central part of the non-coronary cusp was torn and perforated 15 mm long. She is in good condition three years after surgery. Case 2: A 57-year-old male was transferred to the nearest hospital because he was involved in a snowslide accident. A month after the injury, catheterization showed massive aortic regurgitation and pulmonary hypertension. An aortotomy revealed that the intima around the right coronary ostium was completely torn. A perforation with a diameter of 3 mm was also observed on the right coronary cusp. After coronary cusps were excised, interrupted mattress sutures buttressed with pledgets were passed through the aortic wall at the distal level of the intimal laceration and then to the aortic annulus. A 25 mm SJM prosthetic valve was seated at the aortic ring. As the right coronary ostium was included in the plicated aortic wall, aortocoronary bypass was constructed using the great saphenous vein. He is doing well 14 months after surgery. Aortic regurgitation due to blunt trauma is rare and difficult to diagnose. Sometimes cardiac failure progresses rapidly. Therefore, urgent surgery is recommended as soon as the diagnosis is confirmed.

Aortic Aneurysm↗
PubMed1998

[Positive end-expiratory pressure facilitates washout of nitrous oxide in patients with obstructive pulmonary disease].

This study was designed to investigate the relationship between nitrous oxide elimination and each value of pulmonary function tests: percent vital capacity, air way resistance and percent of forced expiratory pressure (FEV1.0%) in patients undergoing general anesthesia. Furthermore, the effect of positive end-expiratory pressure (PEEP) on nitrous oxide elimination was studied. Thirty nine patients, anesthetized by oxygen, nitrous oxide and sevoflurane, were allocated randomly to one of two groups; one, with PEEP 10 cmH2O during nitrous oxide elimination and the other, without. After discontinuation of nitrous oxide, the concentration of nitrous oxide was measured at 15 sec intervals under controlled ventilation with 100% oxygen-sevoflurane. There was a significant correlation between nitrous oxide washout time and FEV1.0% (P < 0.05). Patients were further divided into two subgroups: FEV1.0% of over 70% (normal FEV) and that of less than 70% (low FEV). In the normal FEV group, the washout time was unaffected by PEEP. In the low FEV group, the washout times, with and without PEEP, were 7.07 +/- 0.93 min and 9.13 +/- 2.32 min, respectively. The difference was significant (P < 0.05). These results suggest that patients with chronic obstructive lung disease are at risk of delay in nitrous oxide elimination. This delay was found to be preventable with PEEP.

Aged↗
PubMed1998

[Mechanism of short-term improvement in exercise tolerance after lung volume reduction surgery for severe emphysema].

To investigate the mechanism of short-term improvement in exercise tolerance after lung volume reduction surgery (LVRS) for severe emphysema, we performed six-minute walk tests and pulmonary-function tests, and studied their correlation before and 3-to-5 months after LVRS in 7 patients with severe emphysema who underwent bilateral lung reduction via median sternotomy. Results of the tests showed a 59% increase in the 1-second forced expiratory volume (FEV1), a 25% reduction in the functional residual capacity (FRC), a 49% increase in the maximum voluntary ventilation (MVV), and a 20% increase in the distance walked in 6 minutes (6 MD). The degree of improvement in 6 MD correlated significantly with the degree of improvement in FEV1 (r = 0.97, p < 0.01), in FRC (r = 0.86, p < 0.05), and in MVV (r = 0.87, p < 0.05), and did not correlate with the degree of improvement in pulmonary gas exchange. These results support the hypothesis that an increase in lung elastic recoil after targeted emphysematous resection reduces airflow limitation, and thus leads to a short-term improvement in exercise tolerance after LVRS.

Aged↗
PubMed1998

Surgical complications of pediatric kidney transplantation: a single center experience with the extraperitoneal technique.

PURPOSE: The complex nature of pediatric renal transplantation and the often fragile condition of children with end stage renal disease create the potential for a number of complications. To decrease surgical complications we have performed renal transplantation via the extraperitoneal approach at our institution even in children who weigh less than 20 kg. We retrospectively evaluated whether renal transplantation via the extraperitoneal approach decreases surgical complications in pediatric kidney transplant recipients. MATERIALS AND METHODS: From February 1983 to December 1996, 1,115 patients underwent renal transplantation at our institution, including 60 boys and 47 girls with a mean age of 11.9 years who comprise the study group. Mean weight was 30 kg. at transplantation, and 32 and 75 patients weighed less than 20 and 20 or more kg., respectively. All 107 patients were treated with cyclosporine or tacrolimus based immunosuppression, including methylprednisolone and azathioprine or mizoribine. Living related and cadaveric renal transplantation was performed in 92 and 15 cases, respectively. The extraperitoneal technique was performed in all recipients, even in low weight children. The aorta and inferior vena cava, common iliac artery and vein or hypogastric artery and external vein were used for vascular anastomosis depending on recipient size. The ureter was anastomosed to the bladder via a modification of Paquin's method or an extravesical technique. RESULTS: During observation 7 surgical complications (6.5%) developed, including ureteral stricture, ureteral necrosis, renal artery stenosis, lymphocele, subcapsular hematoma, bladder leakage and significant vesicoureteral reflux to the graft in 1 patient each. There were no gastrointestinal complications. One patient with ureteral necrosis and 1 with subcapsular hematoma required surgical repair, and 1 underwent laparoscopic fenestration of a lymphocele. One patient with ureteral stricture and 1 with bladder leakage were treated conservatively, while another underwent ureteroneocystostomy. Overall only 1 graft (1%) was lost to a surgical complication (renal artery stenosis). CONCLUSIONS: The incidence of surgical complications of the extraperitoneal technique in pediatric renal transplant patients was low (6.5%) and seems to be acceptable. The extraperitoneal technique did not cause any gastrointestinal complications, which seems to be its greatest advantage. The extraperitoneal technique may be used safely even in low weight children.

Adolescent↗
PubMed1998

[Changes in atrial natriuretic peptide and pulmonary hemodynamics induced by exercise in patients with chronic pulmonary emphysema].

We studied the changes in pulmonary hemodynamics induced by arm-stretching exercise in 12 patients with chronic pulmonary emphysema (CPE) and 9 control subjects (Controls). Both patients and control subjects underwent right heart catheterization with inspired gas analysis at rest and during exercise for the 6 minute-exercise test. Mean pulmonary arterial pressure (mPAP) in patients with CPE significantly increased from 18.5 +/- 3.9 mmHg at rest to 25.7 +/- 5.1 mmHg during exercise without decreased oxygen tension of the arterial blood. Both mPAP and total pulmonary resistance increased in proportion to the increases in cardiac output. Mixed venous plasma atrial natriuretic peptide (ANP) was significantly evaluated during exercise in patients with CPE, but did not in Controls. There were a significantly positive relationships between ANP and mPAP, and a significantly negative relationships between ANP and PvO2 during exercise. These results suggest that pulmonary hypertension during light exercise in cases of CPE may be caused by deterioration of the pulmonary capillary bed, and that ANP may be a useful indicator for evaluating pulmonary hypertension in patients with CPE.

Atrial Natriuretic Factor↗