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Biomedical subjects

H Sakamoto

Publications and source records attributed to H Sakamoto.

At least 217 records · Page 12Linked to original sources
PubMed1999

Reduction of operating time and blood transfusion for craniosynostosis by simulated surgery using three-dimensional solid models.

Preoperative planning of craniofacial synostosis can be achieved through the use of two- or three-dimensional (3D) computed tomography (CT) images and by 3D solid models. The advantage of using 3D models was evaluated by calculating the amount of blood transfused and the operating time for 36 craniosynostosis procedures, 21 planned with 3D models and 15 with CT images performed in the past 7 years. The use of 3D models reduced both blood loss and operating time for fronto-orbital advancement with reshaping, LeFort III advancement, and LeFort IV minus Glabellar advancement; blood loss for fronto-orbital advancement without reshaping; and operating time for total cranial reshaping.

Adolescent↗
PubMed1999

Transumbilical embolization of a congenital dural arteriovenous fistula at the torcular herophili in a neonate. Case report.

A neonate, in whom a congenital cerebral vascular anomaly had been diagnosed prenatally, exhibited progressive high-output congestive heart failure soon after birth. Cerebral angiography revealed a congenital dural arteriovenous fistula (AVF) with a huge dural lake located at the torcular herophili. In addition to the meningeal blood supply, an unusual pial blood supply from all cerebellar arteries was observed to feed the fistula. The patient was treated by repeated transarterial and transvenous embolization through the umbilical venous route. To the authors' knowledge, neither the existence of a congenital dural AVF at the torcular herophili presenting with an enormous pial blood supply or the technique of trans-umbilical venous intervention has been reported in the literature.

Arteriovenous Fistula↗
PubMed1999

[A clinical study on long-term outcome in patients with syringomyelia associated with Chiari malformation].

To investigate the long-term outcome in patients with syringomyelia associated with Chiari malformation (chronic tonsilar herniation), we investigated the actual factors of the patient's problems by a questionnaire for the patient. Replies to the questionnaires were obtained from 44 patients with syringomyelia who had been treated with expansive suboccipital cranioplasty with dural plasty (with plugging of the central canal in 20 patients). In 25 cases (68%) in whom the motor dysfunction of the upper extremities remained, the symptoms improved in 16 cases (43%) and were unchanged in 9 cases (24%). In 18 cases (64%) in whom the motor dysfunction of the lower extremities remained, the symptoms improved in 10 cases (36%) and were unchanged in 8 cases (29%). In 31 cases (78%) in whom the sensory disturbance remained, the symptoms improved in 19 cases (48%) and were unchanged in 12 cases (30%). The motor dysfunction of the upper extremities persisted significantly in more patients having a duration of illness over 2 years than in patients with those less than 2 years. Sensory disturbance persisted significantly in more patients with a duration of illness over 3 years than in patients with that less than 3 years. These results suggest that firstly, sensory disturbance (disturbance of the posterior horn) is most apt to remain, then motor dysfunction of the upper extremities (disturbance of the anterior horn) and followed by motor dysfunction of the lower extremities (disturbance of the pyramidal tract). We conclude that patients should be treated before having irreversible spinal cord disturbance.

Adolescent↗
PubMed1999

[Estimation of left internal thoracic artery flow reserve after coronary artery bypass grafting using Doppler flow wire].

The usefulness of the left internal thoracic artery (LITA) for aortocoronary bypass grafting is now established. Reports of variation in LITA graft function are rare. Graft flow was measured using a Doppler flow wire to estimate graft function in 27 patients (24 males, 3 females) who underwent LITA grafting to the left anterior descending artery. Patients were classified into the following 3 groups: Group A consisted of 9 patients with normal left ventricular function and no native flow; Group B consisted of 11 patients with normal ventricular function and good native flow; Group C consisted of 7 patients with abnormal left ventricular function and no native flow. LITA graft function was also estimated 1 year after operation in 12 of these 27 patients (4 in each group). Diastolic/systolic velocity ratio (DSVR) and flow reserve were determined in the proximal, middle, and distal portions of the LITA graft and native left anterior descending artery before and after papaverine administration (8-10 mg). DSVR was significantly higher in the distal portion than in the proximal portion (p < 0.01), but this value did not change after papaverine administration. After 1 year, DSVR in the proximal portion was significantly higher in Group C than in Groups A or B (p < 0.05 for both). Four weeks after operation, the flow reserve of the distal portion was significantly higher in Group A than in Group C (p < 0.001). After 1 year, this value was significantly higher in Group A than in either Groups B or C (p < 0.01, p < 0.001, respectively). The rate of increase in flow reserve in the distal portion was significantly greater in Group A (23.4%) than in groups B (2.53%) or C (1.94%; p < 0.05 for both). The distal portion of the LITA was the best measurement site, since the flow pattern in the LITA graft varied throughout all portions. Diastolic flow velocity in the LITA graft was dominant in patients with myocardial damage. The results indicate that flow reserve of the LITA graft depends on antegrade native coronary flow and distal myocardial damage.

Coronary Artery Bypass↗
PubMed1999

[Surgical repair of postinfarction ventricular septal defect: modified Komeda-David procedure].

Since Cooley first reported surgical repair of postinfarction ventricular septal defect in 1957, there have been technical improvements in this procedure. However, the outcome of surgery has not been gratifying thus far. In 1990, Komeda and associates reported a single patch of bovine pericardium sutured to the healthy myocardium around the infarcted area on the left side of the septum that excludes the infarcted myocardium from the left ventricular cavity; a procedure based on a completely different idea. Since the satisfactory outcome of the surgical treatment in this procedure was obtained in a series of 12 patients, this surgical procedure has been in widespread use in Japan. On the other hand, this procedure has a drawback that there is a difficulty in suturing the patch and may lead to a postoperative residual shunt. We investigated a modified surgical procedure that could overcome this difficulty and would like to report it in this paper. At first, the perforated area should be covered with a felt strip and closed with mattress sutures. Secondly, the infarcted myocardium from the left ventricular cavity should be obliterated using a two-patch method. The primary advantage of this procedure is that it achieves a broader range of vision than a single patch method and enables easy suturing. Additionally, the development of a residual shunt can be prevented owing to the closure of perforation even if sutures fail to hold and leakage occurs. The tow-patch method has the advantage of avoiding tension against sutures since the patch is not everted around the sutures. However, the question arises whether only the healthy myocardium can be picked out and sutured without fail. In order to make the two-patch method more reloable the perforation should be closed in advance.

Aged↗
PubMed1999

[Pancreatic pleural effusion accompanied by bronchopleural fistula].

In recent years, chronic massive pleural effusions have been increasingly recognized as a serious complication of pancreatitis. We describe the third reported case of a pancreatic pleural effusion accompanied by bronchopleural fistula. A 49-year-old man suffering from chronic alcohol-related pancreatitis was admitted to our hospital complaining of cough and shortness of breath. A chest x-ray film disclosed a large right pleural effusion with an air-fluid level. Ultrasonography and computed tomography of the upper abdomen demonstrated a giant pancreatic pseudocyst in the pancreatic tail and a fistulous tract reaching into the posterior mediastinum via the esophageal hiatus. Thoracentesis revealed sterile hemorrhagic fluid with markedly elevated amylase activity of 20,955 IU/l (pancreatic isozyme, 100%) and no malignant cells. A diagnosis of pancreatic pleural effusion was made. The therapy for pancreatic internal fistula is somewhat controversial. We employed conservative therapy, including hyperalimentation and chest tube drainage that successfully decreased the pleural effusion and closed the fistulous tract. Nonetheless, we were still troubled by a continuous air-leak via the drainage tube. Pleurodesis confirmed the tentative diagnosis of bronchopleural fistula and successfully stopped the air-leak. No re-accumulation of pleural effusion has been seen for 2 years. We concluded that pancreatic enzyme-rich effusions, if long-standing, may be complicated by bronchopleural fistula, thus underscoring the need for urgent drainage and initially conservative management.

Bronchial Fistula↗
PubMed1999

Steroid therapy is effective in a young patient with an inflammatory abdominal aortic aneurysm.

We report a successful resection of an inflammatory aneurysm following treatment with steroids in a 23-year-old man. Suffering from fever and severe lumbago, he was admitted to our hospital. An ultrasound and computed tomography of the abdomen revealed an infrarenal abdominal aortic aneurysm surrounded by dense perianeurysmal fibrous tissue. We diagnosed it as an inflammatory abdominal aortic aneurysm based on a symptomatic inflammatory reaction and the findings of ultrasound and computed tomography. Since the aneurysmal wall strongly adhered to the surrounding tissues and surgery was ruled out when it proved impossible to expose the vessels sufficiently to obtain vascular control, steroid therapy was started to control fever and severe lumbago. Five months later, we undertook surgery. Our conclusion is that steroid therapy was very effective against a young patient with inflammatory abdominal aortic aneurysm.

Adult↗
PubMed1999

[Oculomotor nerve and trigeminal nerve involvement demonstrated by Gd-DTPA-enhanced MRI in acute lymphoblastic leukemia: a case report].

Magnetic Resonance Imaging (MRI) is considered a useful procedure for evaluating the intracranial diseases. Leukemic infiltration in either the oculomotor or trigeminal nerve is rarely seen by MRI. We herein describe the diagnostic assessment and outcome of an adult patient suffering from acute lymphoblastic leukemia (L2, FAB). An 18-year-old female was suspected to have ALL. She complained of nausea, vomiting, and double vision for a month, and further examination was required. Fiber gastroscope examination revealed no abnormal lesions in the upper gastrointestinal tract. Furthermore, a plain brain CT indicated no abnormalities in the brain. However, examination of a Gd-DTPA enhanced MRI and the liquor revealed that she had leptomeningeal leukemia with oculomotor and trigeminal nerve infiltration. Systemic administration of methotrexate (MTX) and cytarabine, and intrathecal injection of MTX were partially effective. Repeated Gd-DTPA enhanced MRI showed the shrinkage and reduced enhancement of oculomotor and trigeminal nerve, parallel to the improvement in the liquor. This case demonstrates the importance of MRI not only in the evaluation of therapy, but also in the early diagnosis of central nervous system leukemia.

Adolescent↗
PubMed1999

[An autopsy case of interstitial pneumonia probably induced by Sho-saiko-to].

A 66-year-old woman had been treated for 3 years by her local physician with Sho-saiko-to for chronic hepatitis C virus (HCV) infection and liver cirrhosis. She was admitted to our hospital because of cough, fever, and infiltrative shadows on chest x-ray films. Sho-saiko-to-induced pneumonitis was diagnosed and steroid therapy started. Though a temporary improvement was observed, interstitial pneumonitis relapsed and the patient died of respiratory failure and liver dysfunction. Autopsy findings showed diffuse alveolar damage and honeycombing. Furthermore, reverse-transcriptase polymerase chain reaction techniques detected HCV-RNA in specimens of fibrotic lung tissue. For comparison, HCV-RNA was not histologically detected in lung tissue specimens from 4 control subjects who were positive for HCV antibodies but who did not have interstitial lung disease. It was speculated that the progression of interstitial pneumonia in the present case may have been caused by HCV in combination with Sho-saiko-to-induced lung injury.

Aged↗
PubMed1998

Structures of escherichia coli CMP kinase alone and in complex with CDP: a new fold of the nucleoside monophosphate binding domain and insights into cytosine nucleotide specificity.

BACKGROUND: . Nucleoside monophosphate kinases (NMP kinases) catalyze the reversible transfer of a phosphoryl group from a nucleoside triphosphate to a nucleoside monophosphate. Among them, cytidine monophosphate kinase from Escherichia coli has a striking particularity: it is specific for CMP, whereas in eukaryotes a unique UMP/CMP kinase phosphorylates both CMP and UMP with similar efficiency. RESULTS: . The crystal structure of the CMP kinase apoenzyme from E. coli was solved by single isomorphous replacement and refined at 1.75 A resolution. The structure of the enzyme in complex with CDP was determined at 2.0 A resolution. Like other NMP kinases, the protein contains a central parallel beta sheet, the strands of which are connected by alpha helices. The enzyme differs from other NMP kinases in the presence of a 40-residue insert situated in the NMP-binding (NMPbind) domain. This insert contains two domains: one comprising a three-stranded antiparallel beta sheet, the other comprising two alpha helices. CONCLUSIONS: . Two features of the CMP kinase from E. coli have no equivalent in other NMP kinases of known structure. Firstly, the large NMPbind insert undergoes a CDP-induced rearrangement: its beta-sheet domain moves away from the substrate, whereas its helical domain comes closer to it in a motion likely to improve the protection of the active site. Secondly, residues involved in CDP recognition are conserved in CMP kinases and have no counterpart in other NMP kinases. The structures presented here are the first of a new family of NMP kinases specific for CMP.

Amino Acid Sequence↗
PubMed1998

In vitro effects of gonadotropin-releasing hormone (GnRH) analogue on cancer cell sensitivity to cis-platinum.

Six endometrial cancer cell lines (Ishikawa, EIIL, HEC1A, 6, 50 and 59), one breast cancer cell line (MCF-7) and two ovarian cancer cell lines (OVHS-1, HRA) were treated for 24 or 168 h with a gonadotropin-releasing hormone (GnRH) analogue, Buserelin acetate, and the cellular growth profile was studied. All these cell lines except for the HRA line had positive GnRH receptor mRNA expression detected by reverse transcriptase polymerase chain reaction. GnRHa suppressed cell growth after 168 h of exposure, but not after 24 h. Suppression of cell growth by the exposure to cis-platinum (CDDP, 10 nM for 24 h) was significantly increased in the presence of GnRHa for 168 h. The mechanism of this growth inhibition was tested by examining both RNA components of human telomerase (hTR) expression and telomerase activity. The results showed that GnRHa inhibits telomerase activity without altering the RNA component of telomerase expression. The present data suggest that GnRH analogue may modulate endometrial, breast and ovarian cancer cell growth through modifying the telomerase activity. Since GnRHa increased the cytotoxic effects of CDDP and GnRHa is a compound of high patient compliance, the value of GnRHa as a tumor sensitizer to CDDP should be further tested in clinical trials.

Antineoplastic Agents↗
PubMed1998

Expression of spliceosome-associated protein 49 is required for early embryogenesis in Caenorhabditis elegans.

Spliceosome-associated protein 49 (SAP 49) is a subunit of the splicing factor SF3b, which is involved in 3' splice site recognition in pre-mRNA splicing. Here we show the Caenorhabditis elegans SAP 49 gene is located in a gene cluster that is transcribed polycistronically with three other upstream genes. Transgenic analysis of expression of the gene cluster under the control of its native promoter revealed that in spite of its predicted essential function for all cells, the C. elegans SAP 49 expression is limited to specific cells in both larval and adult stages. When the endogenous SAP 49 expression was inhibited by microinjection of an antisense RNA, embryos laid by the injected worms ceased to develop at a specific stage of early embryogenesis, indicating that SAP 49 plays an essential role in the development of C. elegans. These results raise the possibility that SAP 49 is a cell-specific, not constitutive, splicing factor.

Animals↗
PubMed1998

Leptin receptors in estrogen receptor-containing neurons of the female rat hypothalamus.

This study was undertaken to reveal whether integration of the peripheral signals, leptin and estradiol, that convey information on the metabolic state and gonadal function, respectively, might occur in the same hypothalamic neuronal perikarya. Light and electron microscopic immunolabeling for leptin receptors (LRs) and estrogen receptors (ERs) was carried out on hypothalamic sections of female rats. In the medial preoptic area, periventricular regions, including the parvicellular paraventricular nucleus, the arcuate nucleus and the ventromedial hypothalamic nucleus, all of the cells that expressed immunoreactivity for ERs were also immunopositive for LR. On the other hand, only a subpopulation of LR-containing cells was found to express ERs. The extensive colocalization of receptors for leptin and estrogen in neuronal perikarya of all parts of the hypothalamus suggests a closely coupled interaction between these peripheral signals in the regulation of a variety of behavioral and neuroendocrine mechanisms.

Animals↗
PubMed1998

Spindle disturbances induced by benzo[a]pyrene and 7, 12-dimethylbenz[a]anthracene in a Chinese hamster cell line (V79-MZ) and the stability of the numerical chromosome aberrations that follow.

We previously reported that benzo[a]pyrene (BP) and 7, 12-dimethylbenz[a]anthracene (DMBA) induce aneuploidy and polyploidy, respectively, in the Chinese hamster cell line V79-MZ in the absence of S9 mix. In the present study we investigated the effect of BP and DMBA on the mitotic spindle. BP caused incomplete spindle formation and DMBA inhibited spindle formation completely. The combined results indicate that incomplete spindles caused by BP resulted in aneuploidy, and the absence of spindle formation caused by DMBA resulted in polyploidy. The induced polyploidy was stable for several serial passages in fresh medium. BP and DMBA induced different chromosome number distributions. After BP treatment, the normal distribution of chromosome number was restored in 4 days. After DMBA treatment, on the other hand, a tetraploid peak was maintained for 2 months following an initial transient broad distribution of chromosome number after 1 day. The results suggest that different mechanisms were involved in the induction of numerical aberrations by BP and DMBA. Furthermore the induction of numerical aberrations by BP and DMBA was reproducible over 5 months of passages. In four clones tested, the frequency of cells with the modal chromosome number in control cultures gradually decreased from 82% on the average just after cloning to 62% 5 months later. BP and DMBA induced characteristic ploidy changes following succeeding cell passages for up to 5 months, indicating that the ability to respond to BP and DMBA was stable for that period of time. Because these findings were specific to V79-MZ cells, this cell line might be a good tool for studying chemicals that induce numerical chromosome aberrations.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1998

Structural analysis of oligosaccharides derivatized with 4-aminobenzoic acid 2-(diethylamino)ethyl ester by matrix-assisted laser desorption/ionization mass spectrometry.

Oligosaccharides derivatized with 4-aminobenzoic acid 2-(diethylamino) ethyl ester (ABDEAE) can be analyzed by ESI (Yoshino, K.; et al. Anal. Chem. 1995, 67, 4028-4031) and MALDI (Takao, T.; et al. Rapid Commun. Mass Spectrom. 1996, 10, 637-640) mass spectrometry. In this study, oligosaccharides derived from the enzymatic cleavage of the sugar chains of glycoproteins ribonuclease B, erythropoietin, and transferrin were subjected to ABDEAE derivatization, prior to analysis on a matrix-assisted laser desorption/ionization time-of-flight mass spectrometer (MALDI-TOF MS) for high-resolution mass measurement and a postsource decay (PSD) experiment. In the mass measurement of ABDEAE derivatives, quasi-molecular ion species have been observed in monoisotopic resolution using 2,5-dihydroxybenzoic acid as the matrix from spots that contain 50-200 fmol of sample; in the PSD analyses from the spots contained 500 fmol-1 pmol of sample, the predominant backbone ion series which covers the entire mass range for all the derivatives, the internal ion series which reflect the branched trimannosyl core structure of N-glycans, and the low m/z fingerprint ion of ABDEAE were consecutively observed, permitting structure elucidation of the oligosaccharides. Given the effectiveness of this derivatization in terms of its high sensitivity and resolution with respect to MALDI-TOF MS, current methodology is clearly applicable to the sensitive detection and accurate structural analysis of N-glycans.

Carbohydrate Sequence↗
PubMed1998

CIS3 and JAB have different regulatory roles in interleukin-6 mediated differentiation and STAT3 activation in M1 leukemia cells.

We have reported JAK-signaling modulators, CIS1 (cytokine-inducible SH2 protein-1), CIS3 and JAB (JAK2 binding protein), which are structurally related. In M1 myeloid leukemia cells, CIS3 was induced by neither interleukin 6 (IL6) nor interferon gamma (IFNgamma), while JAB was induced strongly by IFNgamma and slightly by IL6 and leukemia inhibitory factor (ILF). Forced expression of CIS3 and JAB in M1 cells prevented IL6- or LIF-induced growth arrest and differentiation, even when their expression levels were comparable to endogenous ones in several cell lines such as HEL, UT-7, IFNgamma-treated M1, and CTLL2 cells. Pretreatment of parental M1 cells with IFNgamma but not IFNbeta resulted in suppression of LIF-induced STAT3 activation and differentiation, further supporting that physiological level of JAB is sufficient to inhibit LIF-signaling. However, unlike JAB, CIS3 did not inhibit IFNgamma-induced growth arrest, suggesting a difference in cytokine specificity between CIS3 and JAB. CIS3 inhibited STAT3 activation with slower kinetics than JAB and allowed rapid c-fos induction and partial FcgammaRI expression in response to IL6. In 293 cells, CIS3 as well as JAB bound to JAK2 tyrosine kinase domain (JH1), and inhibited its kinase activity, however, the effect of CIS3 on tyrosine kinase activity was weaker than that of JAB, indicating that CIS3 possesses lower affinity to JAK kinases than JAB. These findings suggest that CIS3 is a weaker inhibitor than JAB against JAK signaling, and JAB and CIS3 possess different regulatory roles in cytokine signaling.

Carrier Proteins↗