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Biomedical subjects

Y Sakai

Publications and source records attributed to Y Sakai.

At least 235 records · Page 13Linked to original sources

Cardiac tamponade originating from primary gastric signet ring cell carcinoma.

A 45-year-old man with dry cough and dyspnea was referred by a medical practitioner for evaluation of heart failure on February 10, 1996. Chest X-ray revealed increased cardiothoracic ratio, and ultrasonographic echocardiography disclosed massive pericardial effusion with right ventricular collapse. Cardiac tamponade was diagnosed and pericardiocentesis was performed. Ten days after admission, the pleural effusion had become more pronounced, and thoracocentesis was performed. Carcinoembryonic antigen level was elevated in both the pericardial and pleural effusion, and cytology implicated adenocarcinoma, which suggested malignant effusion. Endoscopic study disclosed gastric cancer in the posterior wall of the upper body, and the histopathological diagnosis was signet-ring cell carcinoma. The patient died of respiratory failure on May 2, 1996, and autopsy was performed. The final diagnosis was gastric cancer with pulmonary lymphangitis, pericarditis, and pleuritis carcinomatosa, accompanied by enlargement of mediastinal and paraaortic lymph nodes. Interestingly, the primary signet-ring cell carcinoma of the stomach was situated mostly in the mucosa. Deep in the submucosal region, there was prominent invasion of the intralymphatic vessels, without direct destruction of the mucosa muscularis.

Carcinoma, Signet Ring Cell↗

Position-independent human beta-globin gene expression mediated by a recombinant adeno-associated virus vector carrying the chicken beta-globin insulator.

The position-independent expression of transgenes in target cells is an essential subject for determining effective gene therapies. The chicken beta-globin insulator blocks the effects of regulatory sequences on transcriptional units at differential domains. We prepared a recombinant adeno-associated virus (rAAV) containing various combinations of the DNase I-hypersensitive site 2 (HS2), 3 (HS3), and 4 (HS4) core elements from the human beta-globin locus control region (LCR), the human beta-globin gene, and the herpes virus thymidine kinase promoter driven neomycin-resistant gene (neoR) (rHS432, rHS43, rHS42, rHS32, and rHS2), and also rAAV containing two copies of the 250-bp core sequence of the chicken beta-globin insulator on both sides of the rHS2 (rIns/HS2/2Ins). After isolating neomycin-resistant mouse erythroleukemia (MEL) cells infected with each rAAV, we analyzed the rAAV genome by Southern blots and polymerase chain reaction (PCR), using primers specific for HS core elements and the human beta-globin gene. All clones contained a single copy of the rAAV genome in the chromosome, however, some of them had a rearranged proviral genome. In five clones with a single unrearranged rAAV genome for each rAAV construct, we assayed the expression of the human b-globin gene relative to the endogenous mouse beta maj-globin gene, using quantitative reverse transcriptase (RT)-PCR. In clones infected with rHS432, the expression level of the human beta-globin gene ranged from 51.6% to 765.6% of that in the mouse beta maj-globin gene. Likewise, in rHS43, the expression level ranged from 36.7% to 259.0%; in rHS42, from 47.8% to 207.0%; in rHS32, from 47.9% to 105.4%; and in rHS2, from 6.1% to 172.1%, indicating a high variability of expression level in clones infected with recombinant virus lacking the insulator. In contrast, in clones infected with rIns/HS2/Ins, the range of expression of the human beta-globin gene ranged from 52.8% to 58.3% of that in the mouse beta maj-globin gene. These results indicate that the insulator functioned dramatically to reduce the variability of transgene expression due to the position effect. This insulator-rAAV vector system holds promise to provide a constant level of transgene expression for gene therapy, regardless of the insertion sites on the chromosome.

Animals↗

Subcellular distribution of protein kinase C isoforms in gastric antrum smooth muscle of STZ-induced diabetic rats.

Contractile responses to carbachol (CCh), protein kinase C (PKC) activity and distribution of PKC isoforms in subcellular fractions isolated from gastric antrum smooth muscle of control and streptozotocin (STZ)-induced diabetic rats were examined. CCh induced concentration-dependent contraction in antrum smooth muscle from controls and diabetics, and this contraction was significantly greater in diabetics than in controls. In diabetics, the PKC activity in the nucleus fraction was significantly decreased by about 63% in the resting condition and that in the cytosol fraction was significantly increased by about 135% after the treatment with 10 microM CCh for 10 min compared to controls. Immunoblot analysis showed that 8 PKC isoforms (-alpha, -beta, -gamma, -delta, -epsilon, -zeta, -iota, -lambda) were expressed in rat antrum smooth muscle. The PKC-beta isoform was significantly decreased by about 47% in the nucleus fraction in the resting condition in diabetics compared to controls. The nucleus, cytosol and membrane fractions of this isoform were decreased in controls after the treatment with 10 microM CCh for 10 min whereas these fractions were unchanged in diabetics. The PKC-epsilon significantly increased by about 219% in the cytosol fraction of diabetics in the resting condition, but the distribution of this isoform was unchanged in controls and diabetics after the treatment with 10 microM CCh for 10 min. Results suggest that the diversity of PKC isoform-specific distribution and translocation may be related to abnormal contractility and intracellular signal transduction through the PKC pathway in diabetics.

Animals↗

Trisomy 10 in a child with acute nonlymphocytic leukemia followed by relapse with a different clone.

We report a 2-year-old Japanese boy with acute nonlymphocytic leukemia (ANLL) having trisomy 10 as the sole chromosomal abnormality. The majority of the marrow blasts had lobulated nuclei and Auer rods in their cytoplasm. The blasts were positive for peroxidase, CD13, CD15, and CD33, but negative for esterase, CD3, CD7, CD34, and HLA-DR, indicating a diagnosis of ANLL, atypical M2 in French-American-British (FAB) classification. He was treated with combination chemotherapy, including anthracyclines, etoposide, and cytosine arabinoside. Four months after achieving the first remission, the disease relapsed during the consolidation therapy, and he died 9 months later. Trisomy 10 was not detected at relapse, and blasts showed phenotypes different from those at initial diagnosis. The present case suggests that the prognosis of acute leukemia with trisomy 10 in the pediatric age group may not be good, and that further studies are required to clarify the association of trisomy 10 with leukemogenesis and disease progression.

Bone Marrow↗

Clinical significance of magnetic resonance imaging (MRI) for focal chondral lesions.

To evaluate the diagnostic potential of magnetic resonance imaging (MRI) and define its role, focal chondral lesions of the femoral surface of the tibiofemoral joint were examined. Full-thickness defects were well detected prospectively (93%) with conventional MRIs initially administered for observation reference of ligaments and menisci. Optimized MRIs, which included right-angled planes to the lesion surface and magnetization transfer contrast (MTC) sequences, delineated the size of lesions (R2 = 0.648,p < 0.0001) and the difference between full-and partial-thickness defects (88% in accuracy). A forward-tilt of 30 degrees to the femoral shaft was the average plane angle that afforded optimal visualization of the chondral lesions. Our findings advocate that routine MRIs are sufficient in detecting severe chondral lesions that require further examination, and the optimized images are highly useful in facilitating the recently developed therapeutic approaches and follow-up studies for articular cartilage defects.

Adolescent↗

Temporally correlated inputs to leaky integrate-and-fire models can reproduce spiking statistics of cortical neurons.

There has been controversy over whether the standard neuro-spiking models are consistent with the irregular spiking of cortical neurons. In a previous study, we proposed examining this consistency on the basis of the high-order statistics of the inter-spike intervals (ISIs), as represented by the coefficient of variation and the skewness coefficient. In that study we found that a leaky integrate-and-fire model incorporating the assumption of temporally uncorrelated inputs is not able to account for the spiking data recorded from a monkey prefrontal cortex. In the present paper, we attempt to revise the neuro-spiking model so as to make it consistent with the biological data. Here we consider the correlation coefficient of consecutive ISIs, which was ignored in previous studies. Considering three statistical coefficients, we conclude that the leaky integrate-and-fire model with temporally correlated inputs does account for the biological data. The correlation time scale of the inputs needed to explain the biological statistics is found to be on the order of 100ms. We discuss possible origins of this input correlation.

Journal Article↗

Twin-tube endografts for aortic aneurysms: an experimental feasibility study.

PURPOSE: To explore feasibility of twin-tube endografts (TTEGs) for treatment of abdominal aortic aneurysm (AAA). MATERIALS AND METHODS: AAAs were created in six dogs by overdilation of Palmaz stents. TTEGs made of seven 9.5-mm-diameter Gianturco Rösch Z (GRZ) stents and covered with PTFE were deployed simultaneously from both femoral arteries through 10-F sheaths to exclude the AAA. Follow-up aortography was performed immediately and at 2, 4, and 8 weeks. Two dogs were killed at 4 weeks and four were killed at 8 weeks. Gross and histologic examinations were performed. RESULTS: AAA creation and TTEG placement were successful in all six dogs. TTEGs completely excluded AAAs in five dogs. Minor temporary perigraft leak was seen in one dog immediately after stent placement. Four dogs had TTEGs patent to termination at 8 weeks. In two dogs with oversized TTEGs, one of the twin endografts occluded at 2 weeks. At autopsy, TTEGs were formed in semicircular shape and histology did not show any significant inflammatory reaction. CONCLUSION: TTEGs show promise for treatment of AAA, with the potential of reducing the introductory sheath size. Further experimental studies, particularly with TTEGs extended into iliac arteries, are warranted.

Angiography↗

Subcellular localization of fructosyl amino acid oxidases in peroxisomes of Aspergillus terreus and Penicillium janthinellum.

Fructosyl amino acid oxidase (FAOD) is the enzyme catalyzing the oxidative deglycation of Amadori compounds, such as fructosyl amino acids, yielding the corresponding amino acids, glucosone, and H(2)O(2). In a previous report, we determined the primary structures of cDNAs coding for FAODs from two fungal strains Aspergillus terreus AP1 and Penicillium janthinellum and we found that both fungal FAODs included the putative peroxisome targeting signal 1 (PTS1) at the carboxyl terminal (Yoshida, N. et al., Eur. J. Biochem., 242, 499-505, 1996). In this study, we determined the intracellular localization of FAODs in these two fungi. Subcellular fractionation experiments and immuno-electronmicroscopic observations, together with the previous findings indicated that the FAODs were localized in peroxisomes of A. terreus AP1 and P. janthinellum. These FAODs were also found to belong to a new member of "peroxisomal sarcosine oxidase family protein" in eucaryotic cells.

Journal Article↗

Citric acid fermentation by magnetic drum contactor: use of methanol and ethanol for higher production.

Use of methanol or ethanol in the magneto-biotechnological technique was found to be enhance citric acid production in a magnetic drum contactor operation with Aspergillus niger AJ 117173. Continuous and repeated-batch fermentations were conducted with the addition of 2% ethanol. Continuous fermentation for 50 d gave a better citric acid yield (85%) and average productivity (3.8 g.l(-1).d(-1)) than repeated-batch fermentation over 60 d (65%, 2.3 g.l(-1).d(-1)).

Journal Article↗

A novel hemiacetal dehydrogenase activity involved in ethyl acetate synthesis in Candida utilis.

Acetate ester synthesis was studied in vitro with the ethyl acetate-producing yeast Candida utilis. The level of enzyme activity observed for the NAD+-dependent hemiacetal dehydrogenase acting on hemiacetal, which was produced non-enzymatically from an alcohol and an aldehyde, was much greater than that for the other enzyme involved in ester synthesis, alcohol acetyltransferase. The level of ethyl acetate synthesis in vivo approximately paralleled the hemiacetal dehydrogenase (HADH) activity. The results suggest that the main pathway for ethyl acetate synthesis in C. utilis involves a novel hemiacetal dehydrogenase activity.

Journal Article↗

Helicobacter pylori and mucosal atrophy in patients with gastric cancer: a special study regarding the methods for detecting Helicobacter pylori.

We assessed the sensitivities of several methods for detecting Helicobacter pylori (culture, histology, rapid urease test, and serology), and evaluated the H. pylori positivity considering the degree of atrophy in the background mucosa in 202 gastric cancer patients and 101 controls. The positivity of H. pylori determined by culture (81%) was significantly higher than that determined by serology (62%) in gastric cancer patients (P < 0.001). The positivities of H. pylori determined by biopsy and/or serology in intestinal (84%) and diffuse (95%) types of gastric cancer were higher than that observed in controls (54%) (P < 0.001). Intestinal-type gastric cancer tended to occur in the atrophic mucosa, in which H. pylori positivity was not different from that in controls after adjusting for the degree of atrophy, whereas diffuse-type gastric cancer was observed more often in the nonatrophic mucosa, in which H. pylori positivity was higher than that in controls even after adjusting for the degree of atrophy.

Aged↗

Intragenic deletion in the gene encoding ubiquitin carboxy-terminal hydrolase in gad mice.

The gracile axonal dystrophy (gad) mouse is an autosomal recessive mutant that shows sensory ataxia at an early stage, followed by motor ataxia at a later stage. Pathologically, the mutant is characterized by 'dying-back' type axonal degeneration and formation of spheroid bodies in nerve terminals. Recent pathological observations have associated brain ageing and neurodegenerative diseases with progressive accumulation of ubiquitinated protein conjugates. In gad mice, accumulation of amyloid beta-protein and ubiquitin-positive deposits occur retrogradely along the sensory and motor nervous systems. We previously reported that the gad mutation was transmitted by a gene on chromosome 5 (refs 10,11). Here we find that the gad mutation is caused by an in-frame deletion including exons 7 and 8 of Uchl1, encoding the ubiquitin carboxy-terminal hydrolase (UCH) isozyme (Uch-l1) selectively expressed in the nervous system and testis. The gad allele encodes a truncated Uch-l1 lacking a segment of 42 amino acids containing a catalytic residue. As Uch-l1 is thought to stimulate protein degradation by generating free monomeric ubiquitin, the gad mutation appears to affect protein turnover. Our data suggest that altered function of the ubiquitin system directly causes neurodegeneration. The gad mouse provides a useful model for investigating human neurodegenerative disorders.

Amino Acid Sequence↗

The prolactin gene is expressed in the mouse kidney.

BACKGROUND: Prolactin (PRL), originally identified as an anterior pituitary hormone exhibiting lactogenic activity, is now recognized as a versatile hormone expressed in a wide variety of tissues. METHODS: In this study, the expression of PRL in the mouse kidney was investigated by solution-phase and in situ reverse transcription-polymerase chain reaction (RT-PCR) methods and immunohistochemistry. RESULTS: Mouse PRL (mPRL) transcript and protein are localized in the parietal epithelial cells of Bowman's capsule. Pit-1 is a positive transcription factor for the expression of the PRL gene. The presence of Pit-1 transcript in the kidney was also assessed by RT-PCR methods. The localization of Pit-1 mRNA coincided well with that of PRL. Immunoreactivity to mouse PRL receptor (mPRL-R) is distributed on the luminal membrane of the proximal tubule cells and the parietal epithelial cells of Bowman's capsule. CONCLUSION: These data indicate that the parietal epithelial cells of Bowman's capsule synthesize PRL de novo and suggest that Pit-1 contributes to the transcriptional regulation of PRL gene expression in the kidney, and PRL expressed in this tissue functions in an autocrine/paracrine fashion.

Animals↗

Percutaneous choledochoscopic treatment of intrahepatic stones, including management of associated biliary stenoses.

BACKGROUND AND STUDY AIMS: Choledochoscopic lithotomy is a useful non-surgical treatment for intrahepatic stones. In patients with stenoses, the procedure often fails, and recurrence rates are high. PATIENTS AND METHODS: The efficacy and risks of choledochoscopic lithotomy using our procedure were investigated in 15 patients with intrahepatic stones, with and without strictures. Long-term follow-up results in patients after successful clearance were also reviewed. The follow-up period ranged from one month to 127 months (mean 75 months). RESULTS: Complete removal of stones was achieved in a mean of 2.0 sessions in all cases. The relationship between the number of sessions and the presence of the stenosis was not significant. One patient (6.7%) who had recurrent stones after complete clearance was successfully treated by repeat choledochoscopy. With regard to the rate of recurrence, there was no difference between patients with stenosis and those without. There was no procedure-related mortality. The rate of procedure-related complications was 6.7%. CONCLUSIONS: Choledochoscopic lithotomy for hepatolithiasis is an effective and safe procedure in most patients, even those with severe biliary stenosis. The choice of the appropriate route for lithotomy and appropriate management of stenoses offers a higher success rate and a lower rate of recurrence.

Aged↗

Histopathologic studies of colorectal postendoscopic resection sites: "skipping electrothermal injury" associated with endoscopic resection procedures.

To elucidate the pathologic changes due to endoscopic resection (ER), 32 post-ER sites in 24 surgically removed colorectal specimens and the previous ER specimens were examined. The depth of all the previous ER specimens was restricted to the submucosa, and all post-ER sites showed submucosal stromal changes of various degrees. Fourteen sites (43.8%) showed muscular or serosal changes. One of these lesions was considered to be a reaction to a tattoo agent, but all the other lesions were considered to represent skipping electrothermal injury caused by electrical current passing through the colorectal wall. The lesions consisted of muscular depletion in the inner layer of the muscularis propria (12 sites, 37.5%), hemorrhage or fibrosis between the inner and outer layers of the muscularis propria (3 sites, 9.4%), and serosal changes (10 sites, 31.3%). These skip regions would be vulnerable to electrical current. These findings suggest that asymptomatic electrothermal injury associated with ER is frequent. Statistically, the electrothermal injury appeared to be related to the size of the previous ER specimens. However. these results also reveal that the ER of tissues <10 mm can cause electrothermal injury and can result in full-thickness necrosis.

Aged↗

Efficacy of endoscopic clipping for bleeding gastroduodenal ulcer: comparison with topical ethanol injection.

OBJECTIVE: Although endoscopic clipping is used widely for the treatment of bleeding gastroduodenal ulcers, clinical trials on its efficacy are scarce. The aim of this study is to assess the efficacy and safety of endoscopic clipping for hemostasis from bleeding gastroduodenal ulcers. METHODS: The present study was designed as a retrospective study using historical controls. One hundred consecutive patients with bleeding gastroduodenal ulcers were treated by endoscopic clipping. The preceding 91 consecutive patients treated by endoscopic pure ethanol injection were regarded as controls. Forty-nine of the clipping group and 41 of the ethanol group had lesions at sites difficult to perform endoscopic manipulation. Hemostatic rates, rebleeding rates, amounts of blood transfusion, and durations of hospital stay were analyzed. RESULTS: The hemostatic rate was 96% in both clipping and ethanol groups, whereas the rebleeding rate was lower (15% vs 29%, p = 0.023) in the former than the latter. In technically difficult cases, the hemostatic rate was comparable (96 vs 90%). CONCLUSION: In patients with bleeding gastroduodenal ulcers, endoscopic clipping may be a choice of therapy because of a low rebleeding rate compared with pure ethanol injection.

Ethanol↗