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Biomedical subjects

S Miyano

Publications and source records attributed to S Miyano.

At least 37 records · Page 2Linked to original sources
PubMed2000

The biomechanical effect of postoperative hypolordosis in instrumented lumbar fusion on instrumented and adjacent spinal segments.

STUDY DESIGN: Change in lumbar lordosis was measured in patients that had undergone posterolateral lumbar fusions using transpedicular instrumentation. The biomechanical effects of postoperative lumbar malalignment were measured in cadaveric specimens. OBJECTIVES: To determine the extent of postoperative lumbar sagittal malalignment caused by an intraoperative kneeling position with 90 degrees of hip and knee flexion, and to assess its effect on the mechanical loading of the instrumented and adjacent segments. SUMMARY OF BACKGROUND DATA: The importance of maintaining the baseline lumbar lordosis after surgery has been stressed in the literature. However, there are few objective data to evaluate whether postoperative hypolordosis in the instrumented segments can increase the likelihood of junctional breakdown. METHODS: Segmental lordosis was measured on preoperative standing, intraoperative prone, and postoperative standing radiographs. In human cadaveric spines, a lordosis loss of up to 8 degrees was created across L4-S1 using calibrated transpedicular devices. Specimens were tested in extension and under axial loading in the upright posture. RESULTS: In patients who underwent L4-S1 fusions, the lordosis within the fusion decreased by 10 degrees intraoperatively and after surgery. Postoperative lordosis in the proximal (L2-L3 and L3-L4) segments increased by 2 degrees each, as compared with the preoperative measures. Hypolordosis in the instrumented segments increased the load across the posterior transpedicular devices, the posterior shear force, and the lamina strain at the adjacent level. CONCLUSIONS: Hypolordosis in the instrumented segments caused increased loading of the posterior column of the adjacent segments. These biomechanical effects may explain the degenerative changes at the junctional level that have been observed as long-term consequences of lumbar fusion.

Adult↗
PubMed2000

Synthesis and diuretic activity of bicyclic fused heterocycles containing oxime-O-sulfonic acid moiety.

In order to investigate the origin of the loop-type diuretic activity of M17055 (1), several variants (3-9) were designed and synthesized by modifying the quinolinone skeleton, and their diuretic activities were compared with the lead 1 and furosemide in dogs. It was found that the negative charge distribution pattern afforded by the dispositional arrangement of the 4-oxime-O-sulfonic acid and 1-N-acyl carbonyl moiety attached to the tetrahydropyridine ring system is inevitable for the development of the activity, which strongly supports the previously proposed model for the active site of the Na(+)-K(+)-2Cl(-) cotransporter. Also reported is the first synthesis of the dihydrothieno[3,2-b]pyridine-7(4H)-one ring system required in the synthesis of compound 9.

Animals↗
PubMed2000

Spontaneous regression of hepatocellular carcinoma and review of literature.

A 68-year-old man presented with multiple hepatocellular carcinoma, which was considered to be unresectable at the first admission in January 1994. Pathological diagnosis was made by biopsy of the one lesion among them. From January 1994 to December 1997, 10 transarterial chemoembolizations and six percutaneous ethanol injection therapies were performed on the tumours in the cirrhotic liver. In February 1998 the tumour situated in the right lobe began to increase in size. The maximum tumour diameter was 6.3 cm measured by computed tomography (CT). In the beginning of May 1998 moderate ascites was present and mild hepatic encephalopathy was noticed. The patient was in the terminal stage of hepatocellular carcinoma and no further treatment was possible at that time. However, serum alpha-fetoprotein and protein induced by vitamin K absence or antagonist II dramatically decreased in June 1998. The CT scan also showed that the tumour had completely regressed without specific treatment. In February 1999 a new biopsy-proven hepatocellular carcinoma, 2 cm in diameter, developed in the lateral segment of the liver. It was well treated by percutaneous ethanol injection therapy. The patient was alive in good condition without any symptoms or tumour recurrence in June 1999. It was concluded that a rare case of spontaneous regression of hepatocellular carcinoma had occurred.

Aged↗
PubMed2000

Value of laparoscopic microwave coagulation therapy for hepatocellular carcinoma in relation to tumor size and location.

BACKGROUND AND STUDY AIMS: The indications for laparoscopic microwave coagulation therapy (LMCT) for hepatocellular carcinoma (HCC) have not yet been adequately evaluated. This study investigated the value of LMCT in the treatment of HCC. PATIENTS AND METHODS: Forty-three patients with liver cirrhosis (including five patients in Child Pugh grade C), with 56 HCC lesions, were enrolled in the study. When dynamic computed tomography (CT) showed a loss in HCC enhancement characteristics and a low concentration area after LMCT, a lesion was judged to have undergone complete necrosis. RESULTS: The rate of complete necrosis for lesions measuring 40 mm or less was significantly higher (P<0.01) than for those measuring 41 mm or more. The rate of complete necrosis for lesions located on the liver surface, excluding those located close to the gallbladder or in contact with the diaphragm, was also significantly higher (P<0.01) than for those situated deep within the liver. The outcome for lesions of 40 mm or less was favorable. Intra-abdominal hemorrhage occurred in two patients, pneumothorax in three, and hepatic infarction in one, all associated with LMCT. However, these patients did not suffer any sequelae of clinical significance. CONCLUSIONS: This study suggests that there is a strong indication for LMCT for HCCs measuring 40 mm or less in diameter and those located on the liver surface even if they are as large as 50 mm, but not for those located close to the gallbladder or in contact with the diaphragm. LMCT appears to be applicable in patients with impaired liver function.

Aged↗
PubMed2000

Algorithms for identifying Boolean networks and related biological networks based on matrix multiplication and fingerprint function.

Due to the recent progress of the DNA microarray technology, a large number of gene expression profile data are being produced. How to analyze gene expression data is an important topic in computational molecular biology. Several studies have been done using the Boolean network as a model of a genetic network. This paper proposes efficient algorithms for identifying Boolean networks of bounded indegree and related biological networks, where identification of a Boolean network can be formalized as a problem of identifying many Boolean functions simultaneously. For the identification of a Boolean network, an O(mnD+1) time naive algorithm and a simple O (mnD) time algorithm are known, where n denotes the number of nodes, m denotes the number of examples, and D denotes the maximum in degree. This paper presents an improved O(momega-2nD + mnD+omega-3) time Monte-Carlo type randomized algorithm, where omega is the exponent of matrix multiplication (currently, omega < 2.376). The algorithm is obtained by combining fast matrix multiplication with the randomized fingerprint function for string matching. Although the algorithm and its analysis are simple, the result is nontrivial and the technique can be applied to several related problems.

Algorithms↗
PubMed2000

Inferring qualitative relations in genetic networks and metabolic pathways.

MOTIVATION: Inferring genetic network architecture from time series data of gene expression patterns is an important topic in bioinformatics. Although inference algorithms based on the Boolean network were proposed, the Boolean network was not sufficient as a model of a genetic network. RESULTS: First, a Boolean network model with noise is proposed, together with an inference algorithm for it. Next, a qualitative network model is proposed, in which regulation rules are represented as qualitative rules and embedded in the network structure. Algorithms are also presented for inferring qualitative relations from time series data. Then, an algorithm for inferring S-systems (synergistic and saturable systems) from time series data is presented, where S-systems are based on a particular kind of nonlinear differential equation and have been applied to the analysis of various biological systems. Theoretical results are shown for Boolean networks with noises and simple qualitative networks. Computational results are shown for Boolean networks with noises and S-systems, where real data are not used because the proposed models are still conceptual and the quantity and quality of currently available data are not enough for the application of the proposed methods.

Algorithms↗
PubMed2000

Algorithms for inferring qualitative models of biological networks.

Modeling genetic networks and metabolic networks is an important topic in bioinformatics. We propose a qualitative network model which is a combination of the Boolean network and qualitative reasoning, where qualitative reasoning is a kind of reasoning method well-studied in Artificial Intelligence. We also present algorithms for inferring qualitative networks from time series data and an algorithm for inferring S-systems (synergistic and saturable systems) from time series data, where S-systems are based on a particular kind of nonlinear differential equation and have been applied to the analysis of various biological systems.

Algorithms↗
PubMed2000

Hybrid Petri net representation of gene regulatory network.

It is important to provide a representation method of gene regulatory networks which realizes the intuitions of biologists while keeping the universality in its computational ability. In this paper, we propose a method to exploit hybrid Petri net (HPN) for representing gene regulatory networks. The HPN is an extension of Petri nets which have been used to represent many kinds of systems including stochastic ones in the field of computer sciences and engineerings. Since the HPN has continuous and discrete elements, it can easily handle biological factors such as protein and mRNA concentrations. We demonstrate that, by using HPNs, it is possible to translate biological facts into HPNs in a natural manner. It should be also emphasized that a hierarchical approach is taken for our construction of the genetic switch mechanism of lambda phage which is realized by using HPNs. This hierarchical approach with HPNs makes easier the arrangement of the components in the gene regulatory network based on the biological facts and provides us a prospective view of the network. We also show some computational results of the protein dynamics of the lambda phage mechanism that is simulated and observed by implementing the HPN on a currently available tool.

Bacteriophage lambda↗
PubMed2000

The medial approach for operative release of post-traumatic contracture of the elbow.

We treated post-traumatic contracture of the elbow in 13 consecutive patients (14 elbows) by operative release. Through a single medial approach, the posterior oblique bundle of the medial collateral ligament was resected, followed by posterior and anterior capsulectomies. An additional lateral release through a separate incision was required in only four elbows. The results were assessed at a mean interval of 57 months after operation. Before surgery active extension lacked 43 degrees which improved to 17 degrees after operation. Active flexion before operation was 89 degrees, which improved to 127 degrees. The mean arc of movement increased from 46 degrees to 110 degrees. All 14 elbows showed scarring of the posterior oblique bundle of the medial collateral ligament. Neither the interval from injury to operative release nor the age of the patient affected the results. A medial approach is useful to reveal and excise the pathological changes in the medial collateral ligament. It is a safe and effective route through which to correct post-traumatic contracture of the elbow.

Adolescent↗
PubMed2000

Lamivudine as an alternative therapy for interferon-resistant chronic hepatitis B and the characteristics of hepatitis B virus: a case report.

A 27-year-old man who had been diagnosed as having chronic hepatitis B suffered disease exacerbation with marked reactivation of hepatitis B virus (HBV). Treatment with interferon (IFN) did not improve his condition, and his serum HBV DNA level increased to over 10 000 pg/ml during IFN administration. Following replacement with lamivudine, there was a substantial reduction in HBV DNA to an undetectable level, and liver function parameters subsequently improved to within the normal range. Quantitative analysis of the precore mutant HBV DNA, which is a variant that cannot express hepatitis B e antigen due to a G-to-A point mutation in the precore region of the viral genome, revealed that the amount present was greater than for the precore wild-type HBV DNA in the serum taken before IFN treatment. This case suggests that lamivudine would be an appropriate alternative to IFN, particularly in patients infected with HBV containing an excess of precore mutants resistant to IFN therapy.

Adult↗
PubMed2000

Syntheses of chirally modified thiacalix

New chirally modified p-tert-butylthiacalix[4]arenes were synthesized via conformation- and/or regioselective etherification with ethyl bromoacetate followed by hydrolysis of the ester moiety and then subsequent amidation with (S)-1-phenyl-ethylamine or (S)-1-(1-naphthyl)ethylamine. These chiral selectors were coated with OV-17 on capillary columns to examine their ability as chiral stationary phases (CSPs) for discrimination of enantiomeric amino acid, amine and alcohol derivatives. It was found that CSP-(S)-4 prepared from cone-shaped tetra-(S)-1-phenylethylamide (S)-4 showed good to fair separations for all the samples examined. On the contrary, the corresponding CSP-(S)-14 prepared from the cone-shaped tetraamide (S)-14 of the parent p-tert-butylcalix[4]arene did not indicate any enantioseparation at all for the same samples, showing that the bridging group of the calix[4]arene ring is critical for the advent of enantioselectivity. The effect of the types and the numbers of the chiral amide groups in the chiral selectors on enantioselectivity was also discussed.

Journal Article↗
PubMed2000

[The studies of hemodynamic changes and liver uptake in a combination of ATP stress test and low workload exercise test on myocardial scintigraphy].

A pharmacological adenosine-tri-phosphoric acid (ATP) stress test has been used in patients who can not perform an enough exercise stress test. However, falling blood pressure during the stress test and increased liver uptake of the tracer are often found in patients undergoing the ATP test. To prevent these phenomena, a combination of ATP stress test and low workload exercise test (ATP & EX) is proposed. The usefulness of this newly developed stress test was elucidated from two viewpoints. Firstly, the changes of hemodynamic parameters were measured in 34 patients: 17 undergoing ATP alone and 17 undergoing ATP & EX. Systolic blood pressure fell from 150 +/- 20 mmHg to 126 +/- 16 mmHg (p < 0.05) for ATP alone. However, it changed from 141 +/- 19 mmHg to 149 +/- 31 mmHg (ns) for ATP & EX. There was a significant fall in systolic blood pressure (> 30 mmHg) in 58.8% for ATP alone and 5.9% for ATP & EX (p < 0.01). Secondly, the ROI count in the liver and heart on an anterior projection image were measured in 38 patients: 11 undergoing ATP alone, 13 undergoing ATP & EX, and 14 undergoing an ergometer exercise test (EX). The ROI count in the liver at 60 minutes after tracer injection were 29.0 +/- 10.7 count/pixel, 21.4 +/- 5.2 count/pixel, 18.3 +/- 4.5 count/pixel for ATP alone, ATP & EX and EX, respectively. The activities for ATP & EX and EX were lower than that for ATP alone (p < 0.05 and p < 0.01). Thus, ATP & EX decreased the rates of the fall of systolic blood pressure and decreased liver uptake of the tracer compared with ATP alone. In conclusion, ATP & EX is a useful stress method for myocardial perfusion scintigraphy in patients who can not perform the enough exercise stress test.

Adenosine Triphosphate↗
PubMed2000

Intelligent system for topic survey in MEDLINE by keyword recommendation and learning text characteristics.

We have implemented a system for assisting experts in selecting MEDLINE records for database construction purposes. This system has two specific features: The first is a learning mechanism which extracts characteristics in the abstracts of MEDLINE records of interest as patterns. These patterns reflect selection decisions by experts and are used for screening the records. The second is a keyword recommendation system which assists and supplements experts' knowledge in unexpected cases. Combined with a conventional keyword-based information retrieval system, this system may provide an efficient and comfortable environment for MEDLINE record selection by experts. Some computational experiments are provided to prove that this idea is useful.

Artificial Intelligence↗
PubMed1999

Case report: Occurrence of hepatocellular carcinoma 4.5 years after successful treatment with virus clearance for chronic hepatitis C.

A 67-year-old man with hepatitis C virus infection and histological features of chronic active hepatitis was treated with human recombinant interferon alpha-2b. He responded successfully to interferon with normalization of serum alanine aminotransferase and continuous eradication of hepatitis C virus. However, 4.5 years after the end of interferon therapy, hepatocellular carcinoma, 20 mm in diameter, was detected by routine ultrasonographic screening. The patient underwent surgical treatment for resection of the hepatocellular carcinoma. The non-cancerous liver tissue was histologically normal. This suggests that patients who have shown a complete response to interferon therapy for chronic hepatitis C should be followed up closely.

Aged↗
PubMed1999

Identification of genetic networks from a small number of gene expression patterns under the Boolean network model.

Liang, Fuhrman and Somogyi (PSB98, 18-29, 1998) have described an algorithm for inferring genetic network architectures from state transition tables which correspond to time series of gene expression patterns, using the Boolean network model. Their results of computational experiments suggested that a small number of state transition (INPUT/OUTPUT) pairs are sufficient in order to infer the original Boolean network correctly. This paper gives a mathematical proof for their observation. Precisely, this paper devises a much simpler algorithm for the same problem and proves that, if the indegree of each node (i.e., the number of input nodes to each node) is bounded by a constant, only O(log n) state transition pairs (from 2n pairs) are necessary and sufficient to identify the original Boolean network of n nodes correctly with high probability. We made computational experiments in order to expose the constant factor involved in O(log n) notation. The computational results show that the Boolean network of size 100,000 can be identified by our algorithm from about 100 INPUT/OUTPUT pairs if the maximum indegree is bounded by 2. It is also a merit of our algorithm that the algorithm is conceptually so simple that it is extensible for more realistic network models.

Algorithms↗
PubMed1999

Analysis of liver single photon emission computed tomography in a case of fulminant hepatic failure.

Fulminant hepatic failure is associated with a high mortality rate. Thus, accurate assessment of hepatic functional reserve and hepatic regeneration is important. We describe a 67-year-old woman who survived subacute hepatic failure. We had an opportunity to monitor the clinical course of the patient using single photon emission computed tomography (SPECT) with 99mTc-galactosyl-human serum albumin (99mTc-GSA) and frequent hematological examinations. On admission, prothrombin time was remarkably prolonged (23.1% of control). The liver uptake of 99mTc-GSA was also considerably low. She responded well to treatment. Four weeks after admission, SPECT analysis showed a dramatic increase in liver uptake of 99mTc-GSA, suggesting promotion of hepatic regeneration. Moreover, functional liver volume calculated from the SPECT data showed a marked increase at 4 weeks after admission, whereas CT scan showed no change at that point. This indicated that SPECT with 99mTc-GSA reflected functional hepatocytes more accurately than liver volume determined by CT scan, which cannot exclude nonfunctional hepatocytes. The patient's condition improved in parallel with the improvements in the indices measured by SPECT and hematological examinations. SPECT analysis is practically useful for the prompt assessment of improvement in patients with fulminant hepatic failure.

Aged↗
PubMed1999

Bio-calculus: Its Concept and Molecular Interaction.

The way for expressing biological systems is a key element of usability. Expressions used in the biological society and those in the computer science society have their own merits. But they are too different for one society to utilize the expressions of the other society. In this paper, we design the bio-calculus that attempts to bridge this gap. We provide syntax which is similar to conventional expressions in biology and at the same time specifies information needed for simulation analysis. The information and mathematical background of bio-calculus is what is desired for the field of computer science. We show the practicality of bio-calculus by describing and simulating some molecular interactions with bio-calculus.

Journal Article↗