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Biomedical subjects

M Kanai

Publications and source records attributed to M Kanai.

At least 145 records · Page 8Linked to original sources
PubMed1996

Molecular cloning and expression of rat liver aminopeptidase B.

We isolated, by immunological screening of a Uni-ZAP XR cDNA library constructed from rat liver mRNAs, a cDNA clone with 2212 base pairs encoding aminopeptidase B (EC 3.4.11.6). The open reading frame encodes a 649-amino acid protein with a theoretical molecular mass of 72,545 Da and bears the consensus sequence of the zinc metalloexopeptidases, indicating that the enzyme belongs to this family, which includes aminopeptidase A, aminopeptidase N, and leukotriene-A4 hydrolase. Escherichia coli SOLR cells infected with the pBluescript phagemid excised from the Uni-ZAP XR vector containing the aminopeptidase B cDNA had a high L-arginyl-beta-naphthylamidase activity. The recombinant protein was purified to homogeneity from the recombinant E. coli extracts. The enzyme had Cl--dependent aminopeptidase activity specifically restricted to the Arg and Lys derivatives and contained 1 mol of zinc per mol of the enzyme.

Amino Acid Sequence↗
PubMed1996

Participation of endodermal epithelial cells on the synthesis of plasma LDL and HDL in the chick yolk sac.

We ultrastructually examined the chick yolk sac endodermal epithelium and evaluated our findings in combination with the biochemical analysis of serum and yolk lipoproteins. Twenty-five to 30 nm-sized particles were demonstrated to be a principal element of the extracellular yolk mass and these were determined to be yolk very low density lipoprotein (VLDL). The particles were shown to be taken up by the epithelial cells via coated pits and engulfed by plasma membrane invaginations together with yolk subdroplets, another element of the yolk mass. Through apical vacuoles, the two yolk elements were incorporated into yolk drops, which were identified to be one of the lysosomal structures by a cytochemical procedure using acid phosphatase (AcP)ase activity. During the last week of incubation, which is the final third of the incubation period, the digestion seemed to progress rapidly in the yolk drops, which came to resemble lipolysosomes; lipoprotein production became active as expressed by an enlarged Golgi apparatus. The newly produced lipoprotein particles were electron-lucent and irregular in size (50-120 nm). They were sequestered in secretory vacuoles and secreted from the vascular surface of the epithelial cells. Finally, the particles were thought to be taken into the vitelline circulation as plasma lipoproteins. The major component of lipoprotein in serum was determined to be low density lipoprotein (LDL) and high density lipoprotein (HDL), while cholesterol content was found to increase during incubation. We concluded that endodermal epithelial cells participate the synthesis of plasma LDL and HDL. For this synthesis the cells probably apply lipids and apo-protein generated from yolk VLDL degradation.

Acid Phosphatase↗
PubMed1996

Changes in glucose transporter 2 and carbohydrate-metabolizing enzymes in the liver during cold preservation and warm ischemia.

In order to examine glucose metabolism in liver grafts during cold preservation (24 and 48 hr), warm ischemia (60 and 120 min), a combination of the two and reperfusion, the amount of protein and mRNA of glucose transporter 2 and the activities of enzymes in glycolysis (glucokinase, phosphofructokinase, pyruvatekinase), gluconeogenesis (glucose 6-phosphatase, fructose 1,6-bisphosphatase), and the pentose phosphate pathway (glucose 6-phosphate dehydrogenase) were measured. It appeared that glucose transport, the pentose phosphate pathway, and gluconeogenesis were maintained during cold preservation and warm ischemia. The activity of glucokinase significantly decreased from the control value of 1.33 +/- 0.23 IU/g protein to 0.70 +/- 0.17 (24 hr, P<0.05) and 0.57 +/- 0.12 (48 hr, P<0.01) only during cold preservation. However, the activity of phosphofructokinase significantly decreased from the control value of 4.37 +/- 0.06 IU/g protein to 2.67 +/- 0.15 (60 min, P<0.0001) and 1.53 +/- 0.06 (120 min, P<0.0001) only during warm ischemia. This indicates that glycolysis deteriorates during both cold preservation and warm ischemia and demonstrates further that the balance between glycolysis and gluconeogenesis shifts to gluconeogenesis. Even when cold preservation was combined with warm ischemia, the activity of glucokinase decreased only during cold preservation and the activity of phosphofructokinase decreased only during warm ischemia. Furthermore, these changes were time-dependent. It is suggested that they can be used as a clock to measure the durations of cold preservation and warm ischemia separately and that the magnitude of an ischemic injury to a liver and a liver graft's viability can be indirectly estimated before transplantation.

Animals↗
PubMed1996

Fungal metabolites. XXI. Characteristics of low energy collision induced dissociation of [M + 2H]2+, [M + H + Na]2+ and [M + 2Na]2+ of peptaibols using electrospray ionization mass spectrometry.

The mass spectral characteristics of selected peptaibols were investigated using electrospray ionization in conjunction with low-energy collision-induced dissociation (CID). Protonated and sodiated molecular species were selected as precursor ions and the resulting CID spectra are discussed with respect to fragmentation characteristics related to the structures of peptaibols. The CID spectra of peptaibols with acetylated N-terminus and with the sub-sequences of Aib-Pro were similar. The CID spectra of [M + 2Na]2+ provided structural information more than those of [M + 2H]2+ and [M + H + Na]2+. The CID of [M + 2Na]2+ can be used to deduce complete sequence information for peptaibols.

Amino Acid Sequence↗
PubMed1996

In vivo uptake of lecithin-coated polystyrene beads by rat hepatocytes and sinusoidal endothelial cells.

BACKGROUND: While phagocytosis by Kupffer cells (stellate perisinusoidal macrophages) is well known and that by endothelial cells also is thought to occur under certain conditions, the uptake of large particles by hepatocytes has not been well studied. We reported previously the selective phagocytic uptake of material by hepatocytes using egg lecithin-coated silicon particles. In the present work, we describe more precisely this process following the injection of lecithin-coated polystyrene beads. Additionally, we consider the possible significance of the transcytotic action by endothelial cells. METHODS: Polystyrene latex beads (240 nm in diameter) composed of two layers of polystyrene and methyl methacrylate with a central void cavity and diameter of 140 nm were injected into male Wister-Imamichi rats. The injections were administered through the hepatic portal vein in a volume of 3 ml (concentration of the lecithin-coated or uncoated beads was 2 mg/ml). Controls received the lecithin alone at a concentration of 2 mg/ml. Liver samples were taken 5, 10, or 15 min after injection, fixed, and processed for ultrastructural analysis. RESULTS: Both lecithin-coated and noncoated beads were mainly incorporated in the Kupffer cells as well as in the endothelial cells. Bristle-coated invaginations were observed in the uptake by both cell types; however, noncoated invaginations were also active in the endothelial cells, especially on the surface facing the perisinusoidal space of Disse. Only coated beads were observed within the space or in the hepatocytes. Once taken up by the hepatocytes, the lecithin-coated beads were found either within lysosomes or in a free state in the cytoplasm. CONCLUSIONS: Uptake of 240 nm lecithin-coated polystyrene beads was observed by Kupffer cells, endothelial cells and hepatocytes. These beads were considered to be transported across the endothelial cells by transcytosis. Pseudopodia and bristle-coated invaginations were not employed by the hepatocytes when incorporating the beads.

Animals↗
PubMed1996

Preoperative intrahepatic segmental cholangitis in patients with advanced carcinoma involving the hepatic hilus.

BACKGROUND: Major hepatic resection for biliary tract carcinoma continues to be a risky operation. In this study we examined the influence of preoperative intrahepatic segmental cholangitis on posthepatectomy mortality. METHODS: We analyzed retrospectively the clinical features of 118 patients who underwent liver resection including more than two segments for biliary tract carcinoma involving the hepatic hilus. RESULTS: Intrahepatic segmental cholangitis was encountered before operation in 22 cases. The morbidity and mortality rates for these patients were significantly higher than those of patients without preoperative cholangitis. Selective percutaneous transhepatic biliary drainage was performed before operation in 11 patients for segmental cholangitis. The morbidity rate of patients after hepatectomy was significantly lower than that of patients treated without percutaneous transhepatic biliary drainage. CONCLUSIONS: The presence of preoperative intrahepatic segmental cholangitis is a major prognostic factor in the outcome of major hepatic resection for biliary carcinoma. Selective percutaneous transhepatic biliary drainage for preoperative intrahepatic segmental cholangitis plays an important role in reducing complications after major hepatic resection.

Adult↗
PubMed1996

Selective percutaneous transhepatic embolization of the portal vein in preparation for extensive liver resection: the ipsilateral approach.

The ipsilateral approach was used at preoperative portal vein embolization in 38 patients with hepatobiliary malignancy. The right anterior portal branch was punctured. Two different 5.5-F triple-lumen balloon catheters were used, and fibrin glue and iodized oil were injected. Portal vein embolization was successful in all cases (right lobe, 24 patients; left lobe and right anterior segment, six; right lobe and left medial segment, three; right posterior segment, two; right anterior segment, one; left lobe, one; and right and caudate lobes, one).

Bile Duct Neoplasms↗
PubMed1996

The relation between crossed cerebellar blood flow and severities of hemiplegia: a technetium-(99m) hexamethylpropylene amine oxine SPECT study using Patlak plot method.

Crossed cerebellar diaschisis (CCD), decrease in crossed cerebellar blood flow (CCBF) (ml/100g/min), is often observed in the cerebral blood flow imaging of hemiplegic patients. We studied the relations between severities of hemiplegia and degrees of CCD. Severities of hemiplegia were evaluated by Brunnstrom stages (Br. stage) of lower limbs. Degree of CCD was evaluated as CCBF and asymmetry index (ASI) (%) of CCBF, which were calculated from technetium-(99m) hexamethylpropylene amine oxine ((99m)Tc HMPAO) SPECT study using Patlak plot method (Matsuda et al. 1992, 1993). We have studied twenty consecutive patients. The CCBF was significantly different between Br. stage II and IV (p = 0.0357), III and IV (p < 0.001) and III and V (p < 0.001). ASI was significantly different between II and IV (p = 0.0357), III and IV (p < 0.001) and III and VI (p = 0.0238). Both of CCBF and ASI of the group of II and III were significantly lower than those of the group of IV, V and VI (p = 0.0033 for CCBF and p = 0.0087 for ASI). We conclude that this study indicate a close correlation between the sevreties of hemplegia and the degrees of CCD.

Aged↗
PubMed1996

[Perioperative management for partial resection of a lymphangioma of the tongue].

Twelve month old boy had been suffering from a neck lymphangioma. Partial resection was carried out in his newborn period at another hospital, and he was obliged to be tracheostomied because of severe airway obstruction due to postoperative edema. He was scheduled for partial glossectomy since his tongue had increased in mass, which could easily be injured by teeth, and he had difficulties in swallowing recently. His airway was not obstructive even during sleep and preoperative MRI showed adequate space around the larynx. We induced anesthesia by a mask and he was subseqently intubated with a fiberscope via his nose because his huge and less mobile tongue could not allow the insertion of a laryngoscope and this might cause bleeding. We did not extubate the endotracheal tube for fear of airway obstruction attributable to postoperative edema. Marked edema around the neck persisted longer than we expected. We tried to evaluate the degree of diminution of edema with MRI twice to decide when extubation could be attempted. However, examination with MRI could not give us useful informations. Consequently we evaluated the timing of extubation by examining whether he could close his mouth or not, whether his tongue could move freely and the degree of edema. We realized lymphangioma caused marked and extensive edema after the operation and we should keep in mind that lymphangioma of the tongue might cause various anesthetic problems especially on airways.

Anesthesia, Inhalation↗
PubMed1995

Amyloid beta-protein ending at Thr43 is a minor component of some diffuse plaques in the Alzheimer's disease brain, but is not found in cerebrovascular amyloid.

The distribution of amyloid beta-protein ending at 40 (A beta 40), 42 (A beta 42), and 43 (A beta 43) were immunocytochemically examined in Alzheimer's brains. A large number of diffuse plaques were stained with A beta 42 antibody (S42), but some were weakly labeled with A beta 43 antibody (S43). Immature and mature plaques were labeled with A beta 40 antibody (S40), S42, and S43. Thus, A beta 42 is the major component of diffuse plaques, the initial phase of plaque formation, and A beta 43 is present as a minor component. Only A beta 40 is present in cerebrovascular amyloid.

Aged↗
PubMed1995

Quantitative analysis of synthetic human calcitonin by liquid chromatography-mass spectrometry.

The quantitative analysis of synthetic human calcitonin (hCT) by micro-liquid chromatography-electrospray ionization mass spectrometry (micro-LC-ESI-MS) is reported. hCT was extracted from plasma by an immobilized antibody column and separated by a micro-LC system. The molecular mass of hCT is 3417, and m/z 1140, corresponding to the [M + 3H]3+ ion, was observed by ESI-MS. This ion was monitored in the selected-ion monitoring mode; rat calcitonin, which is highly homologous to hCT, was used as an internal standard. The calibration curve for the quantification of hCT was linear in the range 10 ng/ml to 1 microgram/ml of plasma.

Amino Acid Sequence↗
PubMed1995

Modified amyloid beta protein ending at 42 or 40 with different solubility accumulates in the brain of Alzheimer's disease.

Serial extraction study of Alzheimer's disease (AD) and control brains revealed 4, 3.7 and 3 kD amyloid beta protein (A beta) species accumulated in AD brains. In the fractions extracted with TBS, 10% SDS and formic acid, considerable amounts of A beta species were recovered in SDS fractions besides TBS and formic acid fractions. Immunoblotting with several site-specific antibodies confirmed not only the presence of 4 kD A beta starting at the first amino acid of A beta but also 2 smaller A beta species with modification of their amino-termini in the highly resolutional Tris/Tricine gel system. A beta solubility using these solvents was associated with both modification of the amino-terminus and length of carboxyl-terminus of A beta. Especially, a large amount of modified A beta was found to be accumulated as forms with different solubility in AD brains.

Aged↗
PubMed1995

Changes in lymphocyte beta 2-adrenoceptors after hepatic resection.

Hepatic resection promotes such a high degree of surgical stress that it induces deterioration of various vital functions, which may involve the breakdown of signal transduction systems. To investigate the influence of surgical stress on signal transduction, we studied ligand-receptor specific binding activity after hepatic resection, focusing on lymphocyte beta 2-adrenoceptors. The maximum binding capacity (Bmax) and the dissociation constant (KD) were determined by radioligand binding assay using (-)3H-CGP12177 as a ligand. In the hepatectomy group, Bmax significantly decreased from 1380 +/- 109 to 799 +/- 49 receptors/cell on postoperative day (POD) 3 and to 802 +/- 93 receptors/cell on POD 7 (P < 0.05). In the control group, however, it did not significantly change after the operation. No significant changes in KD were found in either of these groups. The Bmax alteration was not due to the redistribution of lymphocyte subsets or receptor down regulation, but to the decrease in the Bmax of the individual subset. The hepatectomy group was divided into two groups according to the postoperative arterial ketone body ratio (AKBR): Group A, AKBR maintained at 0.7 or more; and Group B, AKBR decreased to below 0.7. The Bmax decrease, a percentage of the preoperative value, of Group B was significantly smaller than that of Group A (48.4 +/- 3.9 and 72.3 +/- 7.3%, respectively, P < 0.05). These results suggest that intense surgical stress, produced by hepatic resection, may influence even ligand-receptor binding parameters, and the decrease in AKBR can indicate the magnitude of surgical stress.

Adrenergic beta-Antagonists↗
PubMed1995

Laparoscopic splenectomy in children. Preliminary results and comparison with the open technique.

To determine the safety and efficacy of laparoscopic splenectomy (LS) in children, a retrospective review of our preliminary experience using LS was compared to results in patients who previously underwent open splenectomy (OS). From July 1993 to January 1995, we performed eight LS procedures in six children with hereditary spherocytosis (HS) and two with immune thrombocytopenic purpura (ITP). Laparoscopic cholecystectomy was simultaneously done in one case with HS. There were 4 males and 4 females who ranged in age from 5 to 15 years--an average age of 8.8 years. Two cases in the early series required a counterincision because of bleeding. Eleven patients who previously underwent OS in our department were used to compare demographics, operative courses, and surgical outcomes. The ages, genders, diseases, body weights, and spleen weights were comparable between LS group and OS groups. The operative time for the LS group was statistically longer than for the OS group (226 +/- 24 min vs 101 +/- 8 min, P < 0.001). The estimated blood loss in the LS group was similar to that of the OS group (100 +/- 39 ml vs 73 +/- 11 ml. P = 0.97). There were no peri- or postoperative complications in two groups. The postoperative hospital stay of LS group was statistically shorter than that of the OS (6.8 +/- 0.6 days vs 10.4 +/- .05 days, P < 0.0001). LS provided better cosmesis and minimized trauma in children over OS. LS appears to be a safe and effective procedure in children, and is useful in the management of pediatric patients with HS or ITP.

Adolescent↗
PubMed1995

Recurrent hemangiopericytoma of the liver: report of a case.

We present herein the case of a 63-year-old man with a locally recurrent hemangiopericytoma in the hepatic hilum. The patient presented to our hospital for the investigation of elevated transaminases 6 years after undergoing resection of a hemangiopericytoma followed by chemotherapy at another hospital. Various imaging techniques demonstrated a well-circumscribed, hypervascular tumor with central necrosis in the hepatic hilum. Establishing a preoperative diagnosis would have been difficult without the information that he had previously had a hemangiopericytoma of the abdominal cavity. An extended right hepatic lobectomy was performed and histopathological examination confirmed the diagnosis of recurrent hemangiopericytoma. Although hemangiopericytoma is a rare tumor, the clinical presentation and radiologic features of this case were fairly typical.

Antineoplastic Combined Chemotherapy Protocols↗