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Biomedical subjects

Y Sakaguchi

Publications and source records attributed to Y Sakaguchi.

At least 19 recordsLinked to original sources
PubMed2003

Sudden onset of paraparesis caused by hypertrophy of the thoracic posterior longitudinal ligament.

STUDY DESIGN: Case report of a rare form of hypertrophy of the thoracic posterior longitudinal ligament (HPLL), causing paraparesis. OBJECTIVE: To describe this very rare pathological condition in the thoracic spine and the results of surgical intervention. SETTING: A department of orthopaedic surgery in Japan. METHODS: A 61-year-old man presented with acute paraparesis associated with HPLL in the thoracic region. A radiographic and pathological review of the case was conducted. Anterior decompression was performed, and he was followed for 3 years after the operation. RESULTS: Pathologic examination of the surgical specimen revealed proliferation of fibrocartilage and calcification. The patient's paraparesis ameliorated after the operation. CONCLUSION: For this case of myelopathy due to HPLL in the thoracic spine, urgent decompression gave excellent results. Clinical awareness of HPLL may aid correct diagnosis and prompt therapy.

Acute Disease↗
PubMed2002

[Subglottic granuloma with extubating mini-trach II: report of a case].

A case of subglottic granuloma after extubating Mini-trach II is described. The patient went aorto-coronary bypass and Mini-trach II was inserted for suction of sputum. Mini-trach II was extubated 6 days after insertion. The patient complained of dyspnea 3 months later. Examination showed subglottic granuloma. First, we burned the granuloma by laser under local anesthesia. Because the visual field was not good due to vocal cord movement, we failed to resect the granuloma completely. Therefore, we performed laryngo microsurgery under general anesthesia and resected the granuloma perfectly. The patient is in good health without signs of recurrence 6 months after granuloma removal. When we used Mini-trach II, the most important issues are insertion to the cricothyroid membrane, preventing infection, and careful follow-up after removing the Mini-trach II.

Aged↗
PubMed2001

Novel forms of squamous cell carcinoma antigen transcripts produced by alternative splicing.

Squamous cell carcinoma antigen (SCCA) is a member of the ovalbumin serine protease inhibitor family, and the serum level of SCCA is a tumor marker of squamous cell carcinoma. Reverse transcription (RT)-PCR of the squamous cell carcinoma cell line showed the existence of a 156 base shorter transcript compared with that of SCCA1 cDNA. By inverse PCR, we cloned the full length cDNA of this SCCA (SCCA1b). Sequence analysis of the complete 1541 bp SCCA1b cDNA showed that it coded for 338 amino acids and had no typical signal sequence in the NH(2) terminus. The cDNA was expressed in Escherichia coli and the product was detected using Western blotting with antibodies against SCCA. Furthermore, RT-PCR of the full coding region of SCCA2 cDNA from cancer tissue showed the existence of a 63 base short transcript (SCCA2b). A comparison of SCCA1b and SCCA2b cDNA with the SCCA1 and SCCA2 genes showed that these messages were derived from each gene by an alternative splicing mechanism.

Alternative Splicing↗
PubMed2001

EXAFS measurements for liquid Ge-Si alloys.

EXAFS measurements around the Ge-K edge have been carried out for liquid Ge-Si alloys for the first time to investigate the local structure around a Ge atom. To perform the EXAFS measurements for the liquid alloys with high melting temperatures, a new sapphire cell have been developed. The measurements were carried out for the liquid alloys from 10% to 60% of Si and the crystalline ones from 10% to 70% of Si as a reference. EXAFS oscillations, x(k), are observed even at 1480 degrees C for liquid Ge(0.4)Si(0.6). The position of the first peak in the radial distribution function obtained from Fourier transform of x(k) is shifted towards smaller distance for liquid and crystalline alloys with increasing Si concentration. The results of a curve-fit analysis in a harmonic approximation show that Ge-Ge and Ge-Si bonds in the liquid alloys become long with increasing Si concentration while those become slightly short in the crystaline ones.

Journal Article↗
PubMed2001

Target/surround asymmetry in perceptual filling-in.

Four experiments examined how differences in the properties of the target and surround affect the time required for perceptual filling-in. They examined differences in luminance, orientation, spatial frequency, and color. A larger target/surround difference delayed filling-in ('feature difference effect'). Interestingly, exchanging the target and surround properties significantly varied the time ('target/surround asymmetry'). Filling-in was facilitated when the target was brighter and closer to the vertical or horizontal than the surround. Little asymmetry was found in the frequency domain, while significant asymmetry was observed for specific color combinations. These effects are discussed with respect to edge adaptation, feature adaptation, balance of neural activities, and contextual modulation.

Analysis of Variance↗
PubMed2000

Transcriptional activation of the human hematopoietic prostaglandin D synthase gene in megakaryoblastic cells. Roles of the oct-1 element in the 5'-flanking region and the AP-2 element in the untranslated exon 1.

The human hematopoietic prostaglandin D synthase (H-PGDS) gene is highly expressed in human megakaryoblastic cells, in which phorbol ester induces its expression. We characterized the promoter activity of the 5'-flanking region and the untranslated exon 1 (-1044 to +290) of the human H-PGDS gene in human megakaryoblastic Dami cells. Transient expression analysis using the luciferase reporter gene revealed that the 5'-flanking region and the untranslated exon 1 were sufficient for efficient expression of the H-PGDS gene in Dami cells, but not in monocytic U937 cells. Deletion and site-directed mutagenesis of the Oct-1 element in the 5'-flanking region decreased the promoter activity by approximately 30% compared with that of the entire region from -1044 to +290. An electrophoretic mobility shift assay demonstrated that Oct-1 specifically bound to the promoter region. Interestingly, even only untranslated exon 1 (+1 to +290) showed approximately 60% of the promoter activity of the entire region from -1044 to +290. Site-directed mutagenesis of the AP-2 element within the untranslated exon 1 abolished the basal promoter activity as well as its phorbol ester-mediated up-regulation. In AP-2-deficient HepG2 cells, the H-PGDS promoter activity was enhanced by coexpression with AP-2alpha. These findings indicate that the Oct-1 element in the 5'-flanking region acts as a positive cis-acting element and that the AP-2 element in the untranslated exon 1 is crucial for both basal and phorbol ester-mediated up-regulation of human H-PGDS gene expression in megakaryoblastic Dami cells.

Base Sequence↗
PubMed2000

Effects of pterygium on corneal spherical power and astigmatism.

OBJECTIVE: To evaluate prospectively the corneal refractive status before and after pterygium surgery and its relationship with preoperative pterygium size. DESIGN: Prospective, nonrandomized, comparative (self-controlled) trial. PARTICIPANTS: One hundred thirty-six eyes undergoing primary pterygium removal surgery. MAIN OUTCOME MEASURES: Corneal spherical power, astigmatism, surface regularity index (SRI), and surface asymmetry index (SAI) before and after surgery, and the preoperative pterygium size. RESULTS: Before surgery, pterygium size significantly correlated with spherical power (Pearson's correlation coefficient, r = -0.370, P < 0.001), astigmatism (r = 0.600, P < 0.001), SRI (r = 0.367, P < 0.001), and SAI (r = 0.387, P < 0.001). The surgery significantly increased spherical power of the cornea, whereas astigmatism, SRI, and SAI were significantly decreased by the surgery (P < 0.01, paired t test with Bonferroni's correction of P value for multiple comparison). Surgically induced changes in spherical power (r = 0.598, P < 0.001) and astigmatism (r = 0.653, P < 0.001) significantly correlated with the preoperative pterygium size. Precise prediction of the magnitude of refractive changes based on the preoperative pterygium size was difficult. CONCLUSIONS: The presence of pterygium and its removal significantly influence the corneal refraction including spherical power, astigmatism, asymmetry, and irregularity, with the larger pterygium exerting the greater influence.

Adult↗
PubMed2000

Structure and chromosomal localization of human and mouse genes for hematopoietic prostaglandin D synthase. Conservation of the ancestral genomic structure of sigma-class glutathione S-transferase.

Hematopoietic prostaglandin D synthase (H-PGDS) is the key enzyme for the production of the D and J series of prostanoids, and the first recognized vertebrate homolog of sigma-class glutathione S-transferase (GST). We isolated the genes and cDNAs for human and mouse H-PGDSs. The human and mouse cDNAs contained a coding region corresponding to 199 amino-acid residues with calculated molecular masses of 23 343 and 23 226, respectively. Both H-PGDS proteins recombinantly expressed in Escherichia coli showed bifunctional activities for PGDS and GST, and had almost the same catalytic properties as the rat enzyme. Northern analyses demonstrated that the H-PGDS genes were expressed in a highly species-specific manner. Whereas the human gene was widely distributed, in contrast, the mouse gene was detected only in samples from oviduct and skin. By fluorescence in situ hybridization, the chromosomal localization of the human and mouse H-PGDS genes were mapped to 4q21-22 and 3D-E, respectively. The human and mouse H-PGDS genes spanned approximately 41 and 28 kb, respectively, and consisted of six exons divided by five introns. The exon/intron boundaries of both genes were completely identical to those of the sigma-class GST subfamily, although the amino-acid sequences of the latter were only 17.0-21.5% identical to those of either H-PGDS. These findings suggest that the H-PGDS genes evolved from the same ancestral gene as the members of the sigma-class GST family.

Amino Acid Sequence↗
PubMed2000

The assessment of dermatomal level of surgical anesthesia after spinal tetracaine.

UNLABELLED: Transcutaneous electrical stimulation (TES), a 60-mA, 50-Hz continuous square wave, has been considered equivalent to surgical incision. We examined whether TES at a smaller current (10 mA) can be used to predict surgical anesthesia and compare the results with sensory block to cold, pinprick, and touch after the administration of spinal tetracaine. Two groups of 40 consecutive patients, 17-69 yr old and 70 yr old or older received a subarachnoid injection of 0. 5% tetracaine in 10% glucose or saline according to the type of surgery. Patients undergoing abdominal surgery received glucose solution, and those scheduled for lower extremities surgery received saline solution, and thus, the resultant four groups of patients were studied. Neural block was assessed by the loss of sensation to cold, pinprick, touch, and TES at 10 mA (T10s), and tolerance (i.e., the loss of pain or discomfort) to TES at 10 (T10p) and 60 (T60) mA. Dermatomal levels of sensory block to cold, pinprick, and touch that were cephalad to T60 varied widely. In contrast, dermatomal levels of T10s and T10p cephalad to T60 were less variable, and the difference between T10s and T60 was the smallest among all the differences in any groups. Our results demonstrate that, regardless of patient age and baricity of a local anesthetic solution, T10s is a good predictor of T60 equivalent to the dermatomal level of surgical anesthesia. IMPLICATIONS: Our results show that the loss of sensation to transcutaneous electrical stimulation at 10 mA, but not cold, pinprick, or touch, is a good predictor of the dermatomal level of block to transcutaneous electrical stimulation at 60 mA, which is considered equivalent to the dermatomal level of surgical anesthesia after the administration of spinal anesthesia.

Abdomen↗
PubMed2000

Genetic analysis of type E botulinum toxin-producing Clostridium butyricum strains.

Type E botulinum toxin (BoNT/E)-producing Clostridium butyricum strains isolated from botulism cases or soil specimens in Italy and China were analyzed by using nucleotide sequencing of the bont/E gene, random amplified polymorphic DNA (RAPD) assay, pulsed-field gel electrophoresis (PFGE), and Southern blot hybridization for the bont/E gene. Nucleotide sequences of the bont/E genes of 11 Chinese isolates and of the Italian strain BL 6340 were determined. The nucleotide sequences of the bont/E genes of 11 C. butyricum isolates from China were identical. The deduced amino acid sequence of BoNT/E from the Chinese isolates showed 95.0 and 96.9% identity with those of BoNT/E from C. butyricum BL 6340 and Clostridium botulinum type E, respectively. The BoNT/E-producing C. butyricum strains were divided into the following three clusters based on the results of RAPD assay, PFGE profiles of genomic DNA digested with SmaI or XhoI, and Southern blot hybridization: strains associated with infant botulism in Italy, strains associated with food-borne botulism in China, and isolates from soil specimens of the Weishan lake area in China. A DNA probe for the bont/E gene hybridized with the nondigested chromosomal DNA of all toxigenic strains tested, indicating chromosomal localization of the bont/E gene in C. butyricum. The present results suggest that BoNT/E-producing C. butyricum is clonally distributed over a vast area.

Amino Acid Sequence↗
PubMed2000

Characterization of the enzymatic component of Clostridium perfringens iota-toxin.

The iota(a) component (i(a)) of Clostridium perfringens ADP ribosylates nonmuscle beta/gamma actin and skeletal muscle alpha-actin. Replacement of Arg-295 in i(a) with alanine led to a complete loss of NAD(+)-glycohydrolase (NADase) and ADP-ribosyltransferase (ARTase); that of the residue with lysine caused a drastic reduction in NADase and ARTase activities (<0.1% of the wild-type activities) but did not completely diminish them. Substitution of alanine for Glu-378 and Glu-380 caused a complete loss of NADase and ARTase. However, exchange of Glu-378 to aspartic acid or glutamine resulted in little effect on NADase activity but a drastic reduction in ARTase activity (<0.1% of the wild-type activity). Exchange of Glu-380 to aspartic acid caused a drastic reduction in NADase and ARTase activities (<0.1% of the wild-type activities) but did not completely diminish them; that of the residue to glutamine caused a complete loss of ARTase activity. Replacement of Ser-338 with alanine resulted in 0.7 to 2.3% wild-type activities, and that of Ser-340 and Thr-339 caused a reduction in these activities of 5 to 30% wild-type activities. The kinetic analysis showed that Arg-295 and Ser-338 also play an important role in the binding of NAD(+) to i(a), that Arg-295, Glu-380, and Ser-338 play a crucial role in the catalytic rate of NADase activity, and that these three amino acid residues and Glu-378 are essential for ARTase activity. The effect of amino acid replacement in i(a) on ARTase activity was similar to that on lethal and cytotoxic activities, suggesting that lethal and cytotoxic activities in i(a) are dependent on ARTase activity.

ADP Ribose Transferases↗
PubMed2000

Prognosis and surgical treatment of gastric cancer invading the pancreas.

The clinicopathologic characteristics of gastric cancer invading the pancreas have not been determined. Gastrectomy was performed in 282 patients with gastric cancer invading adjacent organs at the Department of Surgery II, Kyushu University Hospital, between 1970 and 1987, and patient data were retrospectively analyzed using univariate and multivariate analyses. Of these patients, 150 (53.2%) had tumors invading the pancreas and 132 had tumors invading adjacent organs other than the pancreas. In both groups, the undifferentiated tissue type with infiltrative growth, lymphatic involvement and lymph node metastasis was common. In cases of pancreas invasion, the extent of lymph node metastasis was more severe, vascular involvement was more frequent and the rate of concomitant liver metastasis was higher. The survival time of the patients with pancreas invasion was shorter compared to patients with cancer invading other organs, and pancreas involvement was one of the independent factors predicting a poor prognosis. With respect to surgical treatment of gastric cancer invading the pancreas, the prognosis was better for cases treated with curative surgery and pancreas resection. Of 39 patients treated with partial resection of the pancreas, the tumor had invaded only the capsule of the pancreas in 18 and the pancreas in the other 21. Pancreas-invasive gastric cancer cells are likely to advance via lymphatic and vascular routes and survival time is shorter, but curative resection can improve the survival rate, and perioperative treatment should be appropriately designed.

Aged↗
PubMed2000

Does adrenaline improve epidural bupivacaine and fentanyl analgesia after abdominal surgery?

The alpha-adrenergic agonists have been demonstrated to have synergistic effects with opioids and local anesthetics in animal research. The present study was performed to determine whether the addition of adrenaline improves the analgesic effects of an epidural infusion of a combination of fentanyl and bupivacaine after abdominal surgery. We studied 90 ASA 1 or 2 patients scheduled for abdominal surgery under epidural anaesthesia, with or without general anaesthesia. Patients were randomly divided into two groups to receive a postoperative epidural infusion of fentanyl 5 micrograms/ml in bupivacaine 0.2%, with or without adrenaline 5 micrograms/ml, at a rate of 2 ml/h for more than 48 hours. Postoperative pain relief was assessed using visual analog scales (VAS), both at rest and during coughing, at 2, 24, and 48 hours after surgery. The number of rescue analgesics and side-effects such as nausea, vomiting, pruritus, respiratory depression, headache, muscle weakness, and hypotension were recorded. Patients who received adrenaline (n = 40) reported significantly lower mean VAS scores than those who received no adrenaline (n = 37), both at rest at 24 hours postoperatively and during coughing at 24 and 48 hours. The number of additional analgesics and incidence of side-effects did not differ between groups. In conclusion, the results of the present study demonstrate that the addition of adrenaline to a combination of fentanyl and bupivacaine improves the quality of epidural analgesia after abdominal surgery. Under the conditions of the study, we did not detect any disadvantage from the addition of adrenaline.

Abdomen↗
PubMed2000

[Neuraxial blockade using image intensifier in patients after spinal instrumentation].

There is scant information in the literature regarding central neuraxial blockade in patients with previous back surgery or severe kyphoscoliosis. This report describes a 58-year-old female and an 84-year-old female with spinal instrumentation who presented for orthopedic surgery under neuraxial blockade. In both cases, multiple attempts of needle insertion using standard technique were unsuccessful, whereas spinal combined with epidural anesthesia was performed successfully using image intensifier. The anatomical considerations and difficulties in achieving reliable neuraxial blockade after spinal instrumentation are reviewed. Neuraxial blockade using image intensifier may provide less technical difficulty and a more reliable result in such patients.

Aged↗
PubMed1999

Crystallization and preliminary X-ray studies of the Ia component of Clostridium perfringens iota toxin complexed with NADPH.

A recombinant Ia component of Clostridium perfringens iota toxin, which ADP-ribosylates actin, was crystallized by the hanging drop vapor diffusion method using PEG4000 as a precipitating agent. The crystals were obtained in the presence of NADPH, which is similar to a real substrate, NADH, and belongs to the space group P1 (a = 47.9 A, b = 54.5 A, c = 103.1 A, alpha = 99.0 degrees, beta = 93.3 degrees, and gamma = 107.2 degrees ). The Matthews coefficient of native crystal was 2.7, assuming 2 mol/asymmetric unit. Native data were collected at 2.4-A resolution. The results from a heavy-atom search showed that lanthanide ions (samarium, holmium) altered the molecular packing, judging from the unit-cell difference. The crystals also belonged to the space group P1 (a = 47.7 A, b = 53.9 A, c = 54.6 A, alpha = 68.9 degrees, beta = 78.3 degrees, and gamma = 73.7 degrees ), which is consistent with only one molecule per asymmetric unit.

ADP Ribose Transferases↗
PubMed1999

Clostridium perfringens beta-toxin is sensitive to thiol-group modification but does not require a thiol group for lethal activity.

The beta-toxin gene isolated from Clostridium perfringens type B was expressed as a glutathione S-transferase (GST) fusion gene in Escherichia coli. The purified GST-beta-toxin fusion protein from the E. coli transformant cells was not lethal. The N-terminal amino acid sequence of the recombinant beta-toxin (r toxin) isolated by thrombin cleavage of the fusion protein was G-S-N-D-I-G-K-T-T-T. Biological activities and molecular mass of r toxin were indistinguishable from those of native beta-toxin (n toxin) purified from C. perfringens type C. Replacement of Cys-265 with alanine or serine by site-directed mutagenesis resulted in little loss of the activity. Treatment of C265A with N-ethylmaleimide (NEM), which inactivated lethal activity of r toxin and n toxin, led to no loss of the activity. The substitution of tyrosine or histidine for Cys-265 significantly diminished lethal activity. In addition, treatment of C265H with ethoxyformic anhydride which specifically modifies histidyl residue resulted in significant decrease in lethal activity, but that of r toxin with the agent did not. These results showed that replacement of the cysteine residue at position 265 with amino acids with large size of side chain or introduction of functional groups in the position resulted in loss of lethal activity of the toxin. Replacement of Tyr-266, Leu-268 or Trp-275 resulted in complete loss of lethal activity. Simultaneous administration of r toxin and W275A led to a decrease in lethal activity of beta-toxin. These observations suggest that the site essential for the activity is close to the cysteine residue.

Amino Acid Sequence↗
PubMed1999

Structural analysis of human SCC antigen 2 promoter.

The squamous cell carcinoma antigen (SCCA) has been used as a circulating tumor marker for the management of squamous cell carcinoma. SCCA consists of a small gene family of at least two in human genome (SCCA1 and SCCA2), which are tandemly arrayed on chromosome 18q21.3 and share 92% identical residues. SCCA expressions are tightly controlled in a tissue-specific manner. To investigate the role of SCCA2 in the cancer cells, we first isolated the human genomic clones, containing the promoter region of SCCA2 gene, and determined the nucleotide sequence surrounding the exon 1. The transcription start site was mapped by primer extension analysis, and a putative TATA box element was found in the 5'-flanking region. Other putative regulatory sequences, which include Ets binding sequence, NF-IL6 binding sequence and IRE consensus sequence, were also found in the region. Analysis of luciferase reporter gene expression in transient transfection showed that the promoter region of SCCA2 gene was located within the region from -424 to +47.

Antigens, Neoplasm↗