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Biomedical subjects

Y Koga

Publications and source records attributed to Y Koga.

At least 109 records · Page 6Linked to original sources
PubMed1999

Role of apoptosis induced by Helicobacter pylori infection in the development of duodenal ulcer.

BACKGROUND: Helicobacter pylori affects gastric epithelium integrity by acceleration of apoptosis. However, it remains unclear what product of the bacteria causes apoptosis, or whether or not the apoptosis is involved in the development of ulcers. AIMS: To elucidate the factor from H pylori that causes acceleration of apoptosis and the role of apoptosis in the development of duodenal ulcer in H pylori infection. PATIENTS: Five H pylori negative healthy volunteers, 47 H pylori positive patients with duodenal ulcer, and 35 H pylori positive patients with gastric ulcer. METHODS: An endoscopic examination was carried out to diagnose ulcers and determine their clinical stage. To analyse apoptosis, a cell cycle analysis was performed using biopsy specimens. RESULTS: There was a significant correlation between the urease activity of the H pylori strain and the level of apoptosis induced by this bacterial strain. Moreover, in duodenal ulcer patients infected with H pylori, the patients with an active ulcer exhibited a significantly higher level of apoptosis than those with ulcers at both the healing and scarring stages. CONCLUSION: These findings suggest that acceleration of apoptosis in the antral mucosa caused by the urease of H pylori plays a crucial role in the development of ulcers in the duodenum.

Adolescent↗
PubMed1999

A novel synthetic anti-acute pancreatitis agent, IS-741.

A novel synthetic drug, IS-741, inhibited cell adhesion in vitro and neutrophil in vivo. Thus, IS-741 inhibited the magnification of pancreatic lesion as well as progression to multiple organ failure in acute pancreatitis models. Furthermore, IS-741 at identical plasma concentrations equally improved the survival rates in animals of various species with severe acute pancreatitis. Based on these observations, it was considered that IS-741 inhibited tissue destruction by neutrophil after inhibiting neutrophil infiltration into the pancreas or other important organs in acute pancreatitis. It was also considered that IS-741 demonstrated various anti-acute pancreatitis effects by interrupting a vicious cycle of inflammation. Therefore, IS-741 is expected to become a useful drug for treating acute pancreatitis and multiple organ failure in clinical settings.

Acute Disease↗
PubMed1999

[Spinal anesthesia for a patient with long-term SMON].

SMON (subacute myelo-optico-neuropathy) may result from clioquinol neurotoxicity. An 81-year-old woman underwent internal fixation for left intertrochanteric fracture. She had been diagnosed as having SMON twenty years previously. Sensory examination revealed paresthesia and decreased deep sensation in the lower extremity. A recent neuropathological report shows that in long-term SMON of about fifteen years, degeneration is located from the medulla oblongata to T5-6. We performed spinal anesthesia of which the level of analgesia was below T5-6 in the present case. The level of anesthesia was determined by the pinprick test, and was recognized as below T10. Postoperatively, both the sensory level of analgesia and vital signs remained stable. There was no worsening of neurological findings after spinal anesthesia, including the postoperative period. In conclusion, spinal anesthesia which was limited to below the level of degeneration could be applied in a case of long-term SMON.

Aged↗
PubMed1999

[Changes in ionized magnesium concentrations during general anesthesia].

The change in ionized magnesium (Mg) was investigated during isoflurane-nitrous oxide-oxygen anesthesia. The patients were divided into two groups by induction method of anesthesia. Group 1 was induced with thiamylal 4 mg.kg-1 and Group 2 was induced with ketamine 1 mg.kg-1. The ionized Mg concentration was recorded by NOVA 8 analyzer and observed during anesthesia. We also recorded the serum concentration of total Mg after administration of thiamylal. During induction of anesthesia and surgery, ionized Mg concentration decreased significantly in both groups. The ionized Mg concentration after administration of thiamylal was significantly lower than that after administration of ketamine. The serum total Mg concentration did not decrease throughout the anesthesia course. The ionized calcium concentration decreased, but the concentration of Na and K remained essentially unchanged. We conclude, therefore, that ionized Mg concentration decreases during surgery under general anesthesia, in part, possibly by the effect of anesthetic agent on the cell membrane itself.

Adult↗
PubMed1999

[Prolonged antinociceptive effect of poly (DL-lactic acid)-fentanyl composites after their intrathecal injection in rats].

We synthesized poly (DL-lactic acid)-fentanyl composites and compared the duration of analgesia after the administration of a single intrathecal dose of these agents in rats. The drug was injected with an intrathecal catheter into the intrathecal space. Fentanyl composites or plain fentanyl in doses of 2.5 or 25 micrograms were administered, respectively. Animals were then tested for analgesia using the tail-flick test. The release rate of fentanyl from fentanyl composites in vitro was also evaluated. The antinociceptive effect of fentanyl composites (25 micrograms) was significantly longer than that of plain fentanyl. Administration of poly (DL-lactic acid) alone did not induce the antinociceptive effect. Four of 7 animals given plain fentanyl (25 micrograms) exhibited temporary respiratory depression, but none of the animals given fentanyl composites showed this response. In vitro experiments demonstrated a slow release of fentanyl from the fentanyl composites. We conclude that the antinociceptive effect of fentanyl can be prolonged when administered as a poly (DL-lactic acid)-fentanyl composite in the intrathecal space with decreased systemic side effects compared with the plain formulation.

Analgesics, Opioid↗
PubMed1999

[Diaphragmatic hernia with omental vessels delineated by computed tomography].

A 50-year-old man was admitted to our hospital for the evaluation of a blunted left costophrenic angle on chest roentgenograms. Chest non-enhanced computed tomographic (CT) scans demonstrated the omentum as a crescent-shaped, fat-dense, mass-like shadow on the left dorsal thoracic wall, contiguous with the abdominal cavity and floating. Omental vessels were recognized as funicular water densities running in the superior-to-inferior direction. Magnetic resonance imaging disclosed that the omental vessels ran continuously from the abdominal cavity into the thoracic cavity through a defect in the diaphragm. Diaphragmatic hernia was diagnosed, and corrective surgery performed. We reported this case because the CT-based delineation of omental vessels protruding into the thoracic cavity is rare.

Hernia, Diaphragmatic↗
PubMed1999

[Lung cancer with chylothorax successfully treated by chemical pleurodesis with OK-432].

A 66-year-old man was admitted to our hospital because of bloody sputum. Chest computed tomographic scans disclosed a right hilar tumor. A tumor in the right upper-lobe bronchus was detected by fiberoptic bronchoscopy. Microscopic examination disclosed moderately differentiated squamous cell carcinoma. The patient was treated with irradiation and combination chemotherapy. Thereafter, right chylous pleural effusion developed and continued to accumulate. Pleurodesis was induced by the intrathoracic injection of OK-432 at 15 KE per dose. Lung cancer with nontraumatic chylothorax is rare. In our patient, pleurodesis with OK-432 was an effective treatment.

Aged↗
PubMed1999

Accuracy verification of the photostereometric system KKN/1B developed for intraoperative measurement of knee movement immediately after total knee arthroplasty.

The function and integrity of the knee joint following total knee arthroplasty (TKA) is determined at first by the design and implantation of the prosthesis, and later by the tension of soft tissues surrounding it. Accurate post-TKA motion data obtained intraoperatively could be used not only to optimize implantation techniques from a kinematic standpoint, but also to improve prosthetic design. We therefore developed a system specifically geared to photostereometric measurement of 6 d.o.f. knee motion. A total of eight LEDs are mounted on the prosthetic components in two sets of four by means of connecting measuring-bows. The positions of the LEDs are detected in three-dimensions by two sets of three linear CCD cameras, located bilaterally relative to the knee. The position and orientation of the femoral component relative to the tibial one are estimated from the positions of all LEDs in the sense of least-squares. Based upon results of various accuracy validation experiments performed after precise camera calibration, static overall accuracy and spatial resolution were considered to lie within 0.52 and 0.11 mm, respectively, at any point on the femoral articular surface.

Arthroplasty, Replacement, Knee↗
PubMed1999

Screw home motion after total knee replacement.

The objective of this study was to evaluate the effect of muscle force and the posterior cruciate ligament on screw home motion in patients with total knee replacement in a posterior cruciate ligament retaining prosthesis (10 knees) and a posterior cruciate ligament substituting prosthesis (10 knees). Screw home motion was examined with only active extension and with two types of externally loaded active extension (2 kg and body weight). Screw home motion was measured with a 6 degrees of freedom electrogoniometer (instrumented spatial linkage). Retaining the posterior cruciate ligament maintained screw home motion, with and without external load to muscles, whereas substituting the posterior cruciate ligament maintained screw home motion only under the full external load of body weight. This was not seen with a 2-kg external load. As for the normal knee, it appears that screw home motion of a prosthetic knee is influenced, not only by the presence of ligamentous structures, but also by the activity of the muscles. The activity of the muscles may have a much greater effect on screw home motion with currently used prosthetic designs than does the presence of ligamentous structures.

Aged↗
PubMed1998

Predictors of sudden cardiac death in hypertrophic cardiomyopathy.

Patients with hypertrophic cardiomyopathy (HC) die suddenly. Proposed risk factors for sudden cardiac death (SCD) in HC are youth, a family history of SCD, syncope, and ventricular tachycardia. Hemodynamic variables have not convincingly proved to be risk factors for SCD. Therefore, this study was designed to examine predictors of SCD in a large number of patients with HC during long-term follow-up periods. The relation of studied variables (clinical, electrocardiographic, echocardiographic, hemodynamic, and exercise test findings) to SCD in 309 patients with HC who were initially diagnosed during 1971 through 1994 (mean follow-up 9.4 years) was examined by multivariate analysis. SCD occurred in 28 patients. Independent predictors of SCD were a smaller difference between peak and rest systolic blood pressure during exercise testing (p=0.006), and higher left ventricular outflow tract pressure gradient at rest (p=0.003). Exercise-related SCD occurred in 8 patients and exercise-unrelated SCD in 20 patients (mean age 28 vs 47 years, p <0.05). Thus, patients of exercise-related SCD were younger and had smaller increases in systolic blood pressure during exercise testing, whereas patients with exercise-unrelated SCD were older and had higher left ventricular outflow tract pressure gradient.

Adolescent↗
PubMed1998

2(1H)-quinolinone derivatives as novel anti-arteriostenotic agents showing anti-thrombotic and anti-hyperplastic activities.

In order to search for anti-arteriostenotic agents, a series of 2(1H)-quinolinone derivatives was synthesized and evaluated for anti-thrombotic activity and for anti-hyperplastic activity. From this series, (-)-6-[3-[3-cyclopropyl-3-[(1R,2R)-2-hydroxycyclohexyl]ureido]propoxy]-2 (1H)-quinolinone (1p, OPC-33509) was selected as the best candidate by balancing the efficacy on anti-thrombosis and anti-hyperplasia.

Animals↗
PubMed1998

A novel ether core lipid with H-shaped C80-isoprenoid hydrocarbon chain from the hyperthermophilic methanogen Methanothermus fervidus.

A new ether lipid core (designated as FU) was found in Methanothermus fervidus total lipid. Comparison with caldarchaeol showed lower mobility of FU on TLC and smaller molecular weight (m/z 1298) by 2 mass units on FAB-MS. Treatment of FU with HI followed by displacement with silver acetate afforded long chain alcohol acetate (ROAc), which was further saponified with mild alkali to its free alcohol (ROH). ROH is the long chain alcohol prepared from FU. The molecular weights of ROAc and ROH were shown by MS to be 1354 and 1186, respectively. These results suggested that the molecular formula of ROH was C80H162O4, and ROH had four hydroxyl groups, and one molecule of ROH was bound with two molecules of glycerol by four ether linkages. Because FU was not oxidized by NaIO4 and specific rotation [alpha]D of FU coincided with that of caldarchaeol, it seems that the ether linkages of FU are formed with hydroxyl groups of the sn-2 and sn-3 positions of each glycerol moiety. The structure of FU was suggested to be a modified caldarchaeol in which two hydrocarbon chains are bridged with a covalent bond. Although a few points remain to be elucidated before the final conclusion can be reached on the structure of FU due to difficulty in complete structure determination done even with every approach currently available, the most possible position of the bridge in FU hydrocarbon was proposed from the data of EI-MS of ROAc and 1H-NMR of FU. The hydrocarbon chain looks like H-shaped C80 isoprenoid.

Ether↗
PubMed1998

Prenatal identification of mos 45,X/46,X,+mar in a normal male baby by cytogenetic and molecular analysis.

We report a case of mos 45,X/46,X,+mar, diagnosed prenatally by amniocentesis, whose physical examination, including external and internal organs, along with serum testosterone values were normal five years after delivery. The mosaic karyotype was seen in 146 of 240 cells examined (amniotic fluid cells, 110/65; placental chorionic villi: 5/4; cord blood, 21/81; cultured skin fibroblasts, 10/90) from 386 metaphases, and the marker chromosome appeared as a small non-fluorescent acrocentric chromosome. All autosomes appeared normal, and no normal Y chromosome could be demonstrated. Analysis of 26 Y-chromosome loci by molecular techniques such as PCR, Southern analysis using multiple Y-specific DNA probes, and Hae III restriction endonuclease assessment of male-specific repeated DNA in the heterochromatic region of the Y chromosome, and fluorescence in situ hybridization (FISH), revealed the marker was derived from a Y chromosome including p terminal to q11.23, and paracentric inversion in the remaining Y long arm. The formation of testes can be considered as existence of SRY (sex-determining region of Y) as a testis-determining factor. The present report illustrates the importance of FISH and molecular techniques as a complement to cytogenetic methods for accurate identification and characterization of chromosome rearrangements in prenatal diagnosis.

Adult↗
PubMed1998

Separation of cyclosporins by high-performance liquid chromatography and mass spectrometric study of cyclosporin metabolites.

A semi-preparative (high-performance liquid chromatography) method for separation of cyclosporin metabolites in a fungal fermentation sample was developed. By using the optimized chromatographic separation, 20 cyclosporin metabolites in a process sample were isolated, and their molecular masses measured by double focusing sector mass spectrometry. The structures of some of the cyclosporin congeners were investigated by tandem sector mass spectrometry using fast atom bombardment ionization. The isobaric cyclosporins D ([Val2] CS) and G ([Nva2] CS) were differentiated by significantly different relative intensities of a fragment ion at m/z 30 [CH4N]+ from a precursor ion at m/z 72 [C4H10N]+. Otherwise the tandem mass spectrometry (MS/MS) spectra of the fragment ions of the two isomers are very similar. Cyclosporin A and iso-cyclosporin A were also analysed by high energy MS/MS. No significant fragment ions were found to provide distinctions between them. Relatively good overviews of process samples containing very similar structures were achieved by combining LC separation, molecular ion recognition and MS/MS characterization.

Amino Acid Sequence↗