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Biomedical subjects

H Kitagawa

Publications and source records attributed to H Kitagawa.

At least 217 records · Page 12Linked to original sources
PubMed1996

[Inhibitory effect of FOY-305 on liver metastasis of the pancreatic cancer].

The potential for hepatic metastasis in nude mice was studied by the intrasplenic implantation method with five human pancreatic cancer cell lines, Capan-1, BxPC-3, AsPC-1, Panc-1, and MIAPaCa-2, especially in relation to serine protease expression, including urokinase-type plasminogen activator and pancreatic trypsinogen 1 (cationic form). The inhibitory effect of a serine protease inhibitor agent, FOY-305, on hepatic metastasis was also a assessed. As a result, the potential for hepatic metastasis was well correlated with expression of pancreatic trypsinogen 1 in these cell lines, and the incidence of metastasis was significantly decreased by FOY-305. These findings suggest that pharmacologic inhibition of serine protease activity may be a new strategy for the therapy of pancreatic cancer metastasis.

Animals↗
PubMed1996

[Early carcinoma of the biliary tract].

Early carcinoma of the biliary tract was defined as cancer cell invasion limited to the mucosal or muscularis propria in the case of the gallbladder, to the mucosal or fibro-muscular layer in the case of carcinoma of the bile duct and to the sphincter of Oddi in the case of the papilla of Vater from a study on the correlation between the depth of cancer invasion and the result of surgery. A few cases, however, have lymph node metastasis, venous invasion, perineural infiltration or involvement of the lymphatic vessels. The surgical procedures should therefore be selected in order to have a good chance for long-term survival. The importance of systematic lymph node dissection to improve survival is emphasize, even in patients with early biliary tract cancer.

Biliary Tract Neoplasms↗
PubMed1996

The apical caecal diverticulum of the chicken identified as a lymphoid organ.

A peculiar structure, observed as a dome-like protrusion at the apex of the caecum, was investigated macroscopically and histologically in healthy White Leghorn chickens. It was hemispheric or spherical in shape and as it consisted of a lumen with a wall occupied by lymphoid tissue, this structure was designated the apical caecal diverticulum (ACD). ACD were detected in 25.2% of examined chickens and had a mean diameter and height of 1.9 mm and 1.2 mm respectively. Histologically, both the lamina propria mucosae and the submucosa of ACD consisted of well developed aggregated lymphoid nodules. Each nodule was covered by follicle-associated epithelium which contained cells resembling M cells. Some secondary nodules extended into the subserosa. The muscularis mucosae and the stratum circulae of the tunica muscularis disappeared near the entrance to ACD. The stratum longitudinale also gradually decreased in thickness around the entrance, becoming an extremely thin layer in the diverticulum wall. At the caecal apex, each stratum of the tunica muscularis was thinner than in the caecal body and separated into several muscle bundles. These bundles were occasionally displaced by developed lymphoid nodules, causing them to protrude into the subserosa. The high frequency of ACD suggests that caecal apex may be sites for immunological surveillance in the chicken caecum. In addition to the intense and frequent antiperistalsis at the apex suggested by Yasukawa (1959), possible causes for the formation of ACD included (1) the fragility of the tunica muscularis at the ACD, and (2) the local removal of the physical supporting structures by the development of lymphoid nodules.

Animals↗
PubMed1995

Microanalysis of glycosaminoglycan-derived disaccharides labeled with the fluorophore 2-aminoacridone by capillary electrophoresis and high-performance liquid chromatography.

A series of disaccharides derived from chondroitin sulfate and heparin/heparan sulfate were derivatized at their reducing ends with the fluorophore 2-aminoacridone. The resulting labeled compounds derived from chondroitin sulfate or heparin/heparan sulfate were well separated and could be quantified by capillary electrophoresis and HPLC with a fluorescence detector. This method was successfully applied to the analysis of the disaccharide composition of sulfated tetra- and hexasaccharides derived from chondroitin sulfate and heparin/heparan sulfate. Remarkably, the saturated and the corresponding unsaturated chondrodisaccharides, the structures of which differ only in their nonreducing terminal uronic acid residues, were also well separated from each other by capillary electrophoresis. This facilitated disaccharide composition analysis of saturated chondrooligosaccharides prepared by testicular hyaluronidase digestion as well as unsaturated chondro- and heparin/heparan sulfate-oligosaccharides prepared by digestion with chondroitinases and heparitinases. The developed method employing the derivatization by 2-aminoacridone in conjunction with capillary electrophoresis or HPLC with a fluorescence detector allows a simple, sensitive, and quantitative disaccharide composition analysis of the glycosaminoglycan-derived oligosaccharides.

Aminoacridines↗
PubMed1995

Intracortical facilitation and inhibition after paired magnetic stimulation in humans under anesthesia.

The evoked spinal cord potential (ESCP) and the evoked compound muscle action potential (ECMAP) after paired transcranial magnetic stimulation were recorded simultaneously in eight subjects undergoing spine surgery. The ESCP was composed of a short-latency initial wave (D-wave) followed by later waves (I-waves). The mean conduction velocity of each wave was approximately 60 m/s. The interstimulus interval (ISI) affected the amplitude of both ESCP and ECMAP; the amplitude was inhibited at short ISIs (2 ms and 5 ms), was facilitated at ISI of 10 ms, and was inhibited again at longer ISIs (50 ms, 100 ms and 200 ms). The changes in later I-waves were prominent compared to the stable D-wave. These results suggest that transcranial magnetic stimulation alters the excitability of the motor cortex by affecting synaptic transmission in corticomotor (CM) neurons. The inhibition of the motor cortex at longer ISIs may contribute to a silent period following transcranial magnetic stimulation.

Aged↗
PubMed1995

Magnetic-evoked compound muscle action potential neuromonitoring in spine surgery.

STUDY DESIGN: Muscle action potentials elicited by paired transcranial magnetic stimulation were recorded during spine surgery in 34 patients. Anesthesia was based on ketamine and fentanyl. OBJECTIVES: To evaluate the optimal anesthetic regimen to be used for transcranial magnetic stimulation, and to determine the clinical import of magnetic-evoked compound muscle action potentials. SUMMARY OF BACKGROUND DATA: Muscle action potential by transcranial magnetic stimulation has been difficult to record under general anesthesia. Ketamine is known to not suppress the muscle responses, although no conclusive clinical study has been reported. METHODS: Paired transcranial magnetic stimulation was delivered as muscle action potentials were recorded from the limb musculature. RESULTS: Neuromonitoring was reliable in 56% of total cases and in 82% of the recent cases after reducing fentanyl dosage. Paired magnetic stimulation was an excellent facilitation technique for reliable monitoring. At higher dosages, fentanyl and ketamine decreased the reproducibility of the responses. CONCLUSIONS: Magnetic-evoked compound muscle action potential neuromonitoring is a sensitive and selective motor pathway monitoring method that covers the entire motor pathway, including the white and gray matter of the spinal cord. Ketamine-based anesthesia is a good choice for this purpose.

Action Potentials↗
PubMed1995

N-acetylgalactosamine (GalNAc) transfer to the common carbohydrate-protein linkage region of sulfated glycosaminoglycans. Identification of UDP-GalNAc:chondro-oligosaccharide alpha-N-acetylgalactosaminyltransferase in fetal bovine serum.

During the course of a study of elucidate the role of modification of the common polysaccharide-protein linkage structure, GlcA beta 1-3Gal beta 1-3Gal beta 1-4Xyl beta 1-O-Ser, in biosynthetic sorting mechanisms of the different sulfated glycosaminoglycan chains, a novel N-acetylgalactosamine (GalNAc) transferase was discovered in fetal bovine serum. The enzyme catalyzed the transfer of [3H]GalNAc from UDP-[3H]GalNAc to linkage tetrasaccharide and hexasaccharide serines synthesized chemically and to various regular oligosaccharides containing terminal D-glucuronic acid (GlcA), which were prepared from chondroitin and chondroitin sulfate using testicular hyaluronidase digestion. The labeled products obtained with the linkage tetra- and hexasaccharide serines and with the tetrasaccharide (GlcA beta 1-3GalNAc)2 were resistant to digestion with chondroitinase AC-II and beta-N-acetylhexosaminidase but sensitive to alpha-N-acetylgalactosaminidase digestion, indicating that the enzyme is an alpha-N-acetylgalactosaminyltransferase. This finding is in contrast to that of Rohrmann et al. (Rohrmann, K., Niemann, R., and Buddecke, E. (1985) Eur. J. Biochem., 148, 463-469), who reported that a corresponding product was susceptible to digestion with beta-N-acetylhexosaminidase. The presence of a sulfate group at C4 of the penultimate GalNAc or Gal units markedly inhibited the transfer of GalNAc to the terminal GlcA, while a sulfate group at C6 of the GalNAc had little effect on the transfer. Moreover, a slight but significant transfer of [3H]GalNAc was observed to an oligosaccharide containing terminal 2-O-sulfated GlcA as acceptor, whereas no incorporation was detected into oligosaccharides containing terminal unsaturated or 3-O-sulfated GlcA units. These results suggest that this novel serum enzyme is a UDP-GalNAc:chondro-oligosaccharide alpha 1-3- or 1-4-N-acetylgalactosaminyltransferase. The possibility of involvement of this enzyme in glycosaminoglycan biosynthesis is discussed.

Acetylgalactosamine↗
PubMed1995

Physiologic changes of nerve root during posterior lumbar discectomy.

STUDY DESIGN AND OBJECTIVES: The effects of nerve root retraction in posterior discectomy on pressure, blood flow, and electrophysiologic changes of the nerve root were investigated. OBJECTIVES: This study was performed to assess the effects of nerve root retraction in posterior discectomy on pressure, blood flow, and electrophysiologic changes of the nerve root. SUMMARY OF BACKGROUND DATA: The effects of compression on nerve tissue have been clinically studied mainly in peripheral nerves. The potential risk for lumbar nerve root injury has not been evaluated precisely in humans. METHODS: Among 31 patients with lumbar intervertebral disc herniation, the correlation between retraction pressure and changes in blood flow of the nerve root was evaluated. Retraction pressure was continuously monitored during the discectomy and the length of the discectomy procedure was measured. Threshold and amplitude of compound muscle action potentials were monitored before and after discectomy. The relationship between intraoperative data on nerve root physiology and postoperative neurologic change was analyzed. RESULTS: Nerve root blood flow was decreased to 18-30% of the initial value under the pressure around 70 g/cm2. An abrupt decrease in nerve root blood flow was observed even within 1 or 2 mm of retraction distance. The threshold of the nerve root before retraction was minimal in the nerve root of the asymptomatic side, but increased in the affected root demonstrating sensory loss only, and significantly increased in the root showing sensory/motor deficit. Amplitude of compound muscle action potentials evoked by the stimulation at distal from herniated mass was lowest in the nerve root showing sensory/motor deficit. In 4 of 31 patients, high retraction pressure (> 170 g/cm2) was required and they showed temporary sensory deterioration after surgery. The length of discectomy procedure in these 4 patients was 14.1 +/- 4.1 minutes, but it was 9.9 +/- 2.7 minutes in the remaining 27 patients. CONCLUSIONS: In posterior lumbar discectomy, nerve root ischemia usually occurs during retraction. The magnitude of pressure and time of retraction may be potential risk factors for nerve root injury.

Adolescent↗
PubMed1995

Large-scale expression of recombinant sialyltransferases and comparison of their kinetic properties with native enzymes.

Values of Km were determined for three purified sialyltransferases and the corresponding recombinant enzymes. The enzymes were Gal beta 1-4GlcNAc alpha 2-6 sialyltransferase and Gal beta 1-3(4)GlcNAc alpha 2-3 sialyltransferase from rat liver; these enzymes are responsible for the attachment of sialic acid to N-linked oligosaccharide chains; and the Gal beta 1-3GalNAc alpha 2-3 sialyltransferase from porcine submaxillary gland that is responsible for the attachment of sialic acid to O-linked glycoproteins and glycolipids. A procedure for the large scale expression of active sialyltransferases from recombinant baculovirus-infected insect cells is described. For the liver enzymes values of Km were determined using rat and human asialo alpha 1 acid glycoprotein and N-acetyllactosamine as variable substrates; lacto-N-tetraose was also used with the Gal beta 1-3(4)GlcNAc alpha 2-3 sialyltransferases. Antifreeze glycoprotein was used as the macromolecular acceptor for the porcine enzyme. Values for Km were also determined using CMP-NeuAc as the variable substrate.

Animals↗
PubMed1995

Unilateral pulmonary agenesis with tracheoesophageal fistula: a case report.

The authors describe a neonate with unilateral pulmonary agenesis and esophageal atresia (Gross type C). Definitive repair for the atresia was completed during the early neonatal period, and the patient is alive and well more than 1 year after surgery. Most patients with pulmonary agenesis associated with esophageal atresia have not survived, mainly because of postoperative cardiorespiratory failure. Early protection and preservation of respiratory units is essential for the management of these patients.

Esophageal Atresia↗
PubMed1995

Induction of bone resorbing-activity by mouse stromal cell line, MC3T3-G2/PA6.

Unfractionated mouse long-bone cells prestimulated with rat parathyroid hormone (PTH) for 7 days (PTH-prestimulated long-bone cells; PTH-psLB cells) contained about 20% tartrate-resistant acid phosphatase (TRAP)-positive mononuclear cells and about 0.2% TRAP-positive multinucleate cells. When PTH-psLB cells (1.0 x 10(5)/slice) were cultured on dentine slices, about 100 resorption lacunae (pits) per slice were formed by 6 h after the start of culture, while the number of TRAP-positive multinucleate cells on the dentine slices did not increase. When the number of inoculated cells was plotted versus the number of pits formed during the 6-h cultivation, a sigmoid curve was generated. When PTH-psLB cells (1.0 x 10(3)/slice) were cocultured with various mouse stromal cell lines, the MC3T3-G2/PA6 line was found to increase the number of pits. Since this activity was manifested within a short period of time (4 h), and as there was no change in the number of TRAP-positive multinucleate cells, we postulate that the activity of MC3T3-G2/PA6 is exerted on mature osteoclastic cells capable of resorbing bone rather than on some differentiation step of the osteoclast cell lineage. With respect to the mechanism of expression of this activity, it is unlikely that MC3T3-G2/PA6 produces a soluble factor, because no activity was seen when MC3T3-G2/PA6 and PTH-psLB cells were cultured separately across a membrane in a Transwell. These results suggest that cell-to-cell contact and communication between PTH-psLB cells and MC3T3-G2/PA6 may be a crucial event for the stimulation of osteoclastic bone resorption by MC3T3-G2/PA6.

Animals↗
PubMed1995

Detection and characterization of UDP-GalNAc: chondroitin N-acetylgalactosaminyltransferase in bovine serum using a simple assay method.

We report the occurrence, in bovine serum of a soluble form, of N-acetylgalactosaminyl-transferase activity, which is involved in chondroitin sulfate biosynthesis, and we describe a simple assay method for the enzyme. Chondroitin with the general structure [GlcA-GalNAc], was found to serve as acceptor substrates for the enzyme. To develop a routine assay, bovine serum was incubated with polymeric chondroitin and UDP-[3H]GalNAc. After the removal of labeled endogenous acceptors derived from serum by trichloroacetic acid treatment, the labeled chondroitin sulfate chains were separated from residual unincorporated label by centrifugation using syringe columns packed with Sephadex G-25, and the effluent fractions were monitored by scintillation counting. This simple method allowed us to perform multiple assays and to establish assay conditions for the serum N-acetylgalactosaminyltransferase involved in chondroitin polymerization.

Animals↗
PubMed1995

The effect of follicular fluid on intracellular free calcium levels in human spermatozoa.

In this study, we demonstrate the effect of follicular fluid (FF) on free cytosolic calcium ion ([Ca2+]i) in human spermatozoa, using a fluorescent indicator "fura 2," and we evaluate the factors that increase [Ca2+]i in FF. A significant and immediate [Ca2+]i increase (656.3 +/- 148.6 nM) was elicited by intact FF. The increase in [Ca2+]i elicited by lipid-stripped FF was only 50% (322 +/- 68.7 nM) of that elicited by intact FF. However, 82% of the [Ca2+]i increase elicited by intact FF was observed when lipid-stripped FF was supplemented with progesterone, but not when it was supplemented with estradiol. Also, progesterone at the concentrations of 1 ng/ml to 1 microgram/ml caused a significant increase in [Ca2+]i by itself, but estradiol produced a small effect, ranging from 3% to 9% of the effect produced by progesterone. These results indicate that progesterone plays a major role in the lipid fraction in FF to elicit the entry of calcium into human spermatozoa.

Calcium↗
PubMed1995

Decreased mitogenic and osteogenic responsiveness of calvarial osteoblasts isolated from aged rats to basic fibroblast growth factor.

Osteoporosis seen in aged individuals is represented by the reduced bone mass most likely resulting from decreased bone formation by osteoblasts. To examine whether aging causes a decrease in osteoblast activity, calvarial osteoblasts were isolated from aged rats (AOB) and studied for the capacity of the cells to form mineralized bone-like nodules in comparison with that of fetal calvarial osteoblasts (FOB). There were no significant differences in basal mineralized bone-like nodule formation determined by quantifying the size of the nodules which were formed in the cultures of AOB and FOB. However, the responsiveness of AOB to growth factors was profoundly reduced. AOB showed only marginal increase in mineralized bone-like nodule formation and growth in response to basic fibroblast growth factor (bFGF). On the other hand, bFGF markedly promoted mineralized bone-like nodule formation and proliferation in FOB. These results suggest that decreased responsiveness to local osteotropic growth factors such as bFGF might account for the reduced bone formation by aged osteoblasts, which in turn leads to the loss of bone mass characteristic for senile osteoporosis.

Aging↗
PubMed1995

A canine case of discoid lupus erythematosus with circulating autoantibody.

A nine-year-old Shetland sheepdog was diagnosed as discoid lupus erythematosus by clinical features, histopathologic findings, positive direct immunofluorescence, negative antinuclear antigen test and the absence of multisystemic diseases. The indirect immunofluorescence test of this patient dog with the salt split skin showed the deposition at the bottom of the cleft at basement membrane zone (BMZ). Western immunoblotting revealed the 120 kDa and the 85 kDa proteins targeted by the autoantibody. These proteins did not correspond with the known BMZ component.

Animals↗
PubMed1995

Systemic oxygen delivery and consumption in dogs with heartworm disease.

To investigate systemic oxygen (O2) transport, we calculated the oxygen delivery index (Do2I), oxygen consumption index (Vo2I) and oxygen extraction ratio (ER) in dogs with heartworm (HW) disease. The Do2I was 770 +/- 331 ml/min/kg in dogs mildly affected with pulmonary HW disease showing respiratory signs, mild anemia and mild cardiac insufficiency (n = 34); 238 +/- 155 ml/min/kg in dogs with ascitic pulmonary HW disease (n = 7); and 577 +/- 320 ml/min/kg in dogs with caval syndrome (CS) which survived (n = 15) or died (n = 7) after surgical HW removal. The Do2I was lower (P < 0.01) in all HW-infected groups, especially in ascites and CS-non-surviving dogs, than in HW-free dogs (n = 11, 1041 +/- 264 ml/min/kg). The Vo2I was higher in some mildly affected dogs (161 +/- 88 ml/min/kg), and lower (P < 0.01) in ascitic dogs (45 +/- 53 ml/min/kg) than in HW-free dogs (123 +/- 44 ml/min/kg). The ER was higher (P < 0.01) in all HW-infected groups than in HW-free dogs. The Do2I correlated significantly with Vo2I (r = 0.84, P < 0.01), and the Vo2I correlated significantly with ER (r = 0.48, P < 0.01). The Do2I correlated significantly with arterial O2 tension (r = 0.33), serum LDH (r = -0.46) and CK (r = -0.46) activities, serum urea nitrogen (UN, r = -0.32) and lactic acid (LA, r = -0.39) concentrations and cardiac index (r = 0.64).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗