Biomedical subjects

M Furuse

Publications and source records attributed to M Furuse.

At least 127 records · Page 7Linked to original sources

PubMed1996

Interspecies diversity of the occludin sequence: cDNA cloning of human, mouse, dog, and rat-kangaroo homologues.

Occludin has been identified from chick liver as a novel integral membrane protein localizing at tight junctions (Furuse, M., T. Hirase, M. Itoh, A. Nagafuchi, S. Yonemura, Sa. Tsukita, and Sh. Tsukita. 1993. J. Cell Biol. 123:1777-1788). To analyze and modulate the functions of tight junctions, it would be advantageous to know the mammalian homologues of occludin and their genes. Here we describe the nucleotide sequences of full length cDNAs encoding occludin of rat-kangaroo (potoroo), human, mouse, and dog. Rat-kangaroo occludin cDNA was prepared from RNA isolated from PtK2 cell culture, using a mAb against chicken occludin, whereas the others were amplified by polymerase chain reaction based on the sequence found around the human neuronal apoptosis inhibitory protein gene. The amino acid sequences of the three mammalian (human, murine, and canine) occludins were very closely related to each other (approximately 90% identity), whereas they diverged considerably from those of chicken and rat-kangaroo (approximately 50% identity). Implications of these data and novel experimental options in cell biological research are discussed.

Amino Acid Sequence↗

PubMed1996

Anatomical configuration of the spinal column in the supine position. III. Comparison of adolescent and adult volunteers.

To clarify the anatomical configuration of the spinal column in the adolescent in the supine position, we have studied 10 adolescent (13-17 yr) and 10 adult (26-38 yr) volunteers using magnetic resonance imaging. T1-weighted sagittal midline magnetic resonance images of the spinal column were obtained with subjects in the supine position. The maximum angles of decline of the lumbar spinal canal did not differ between the adolescent (mean 13.6 (SD 3.3) degrees) and adult (12.4 (3.8) degrees) groups. The maximum angles of incline of the upper thoracic spinal canal were smaller in the adolescent group (15.9 (4.7) degrees) than in the adult group (26.4 (5.8) degrees). The median highest point of the lumbar spinal canal was located at L4 (range L3-4 to L4-5) in both groups. The lowest points of the thoracic spinal canal in the adolescent and adult groups were located at T8-9 (T7 to T9) and T8 (T6-7 to T9), respectively. This study showed that thoracic kyphotic curvature in adolescents was reduced significantly in the supine position compared with that in adults. This minimized thoracic kyphosis may explain, in part, the enhanced cephalad spread of subarachnoid hyperbaric anaesthetic solutions in adolescents.

Adolescent↗

PubMed1996

Dynamics of cerebral blood flow and metabolism in patients with cranioplasty as evaluated by 133Xe CT and 31P magnetic resonance spectroscopy.

OBJECTIVE: Prolonged improvement in neurological and mental disorders has been seen after only cranioplasty in patients initially treated with external decompression for high intracranial pressure. The objective was to evaluate, using 133Xe CT and 31P magnetic resonance spectroscopy (MRS), how restoring the bone itself can influence cerebral blood flow and cerebral energy metabolism after high intracranial pressure is attenuated. METHODS: Seven patients (45-65 years old) who had undergone external decompression to prevent uncontrollable intracranial hypertension after acute subarachnoid haemorrhage were evaluated. Cerebral blood flow and metabolic changes were evaluated before and after cranioplasty. RESULTS: The ratio of phosphocreatine to inorganic phosphate (PCr/Pi), which is a sensitive index of cerebral energy depletion, was calculated and beta-ATP was measured. The cerebral blood flow value in the thalamus was normalised, from 44 (SD 9) to 56 (SD 8) ml/100 g/min (P < 0.01) and the value in the hemisphere increased from 26 (SD 3) to 29 (SD 4) ml/100 g/min on the side with the bone defect. The PCr/Pi ratio improved greatly from 2.53 (SD 0.45) to 3.01 (SD 0.24) (P < 0.01). On the normal side, the values of cerebral blood flow and PCr/Pi increased significantly (P < 0.01) after cranioplasty, possibly due to transneural suppression. The pH of brain tissue was unchanged bilaterally after cranioplasty. CONCLUSION: Cranioplasty should be carried out as soon as oedema has disappeared, because a bone defect itself may decrease cerebral blood flow and disturb energy metabolism.

Aged↗

PubMed1996

Early-stage rheumatoid arthritis: diagnostic accuracy of MR imaging.

PURPOSE: To investigate the role of magnetic resonance (MR) imaging in diagnosing early rheumatoid arthritis (RA). MATERIALS AND METHODS: Twenty patients (three men, 17 women; age range, 21-72 years) with clinically and radiologically proved RA underwent evaluation to define an MR imaging criterion for diagnosing synovial inflammation due to RA. Twenty-seven patients (16 with RA, 11 without RA [control patients]; three men, 24 women; age range, 19-75 years) suspected to have early RA but without radiographic abnormalities underwent evaluation to test the accuracy of using the criterion to diagnose RA. In each patient, coronal, fat-suppressed, and gadolinium contrast material-enhanced, T1-weighted images of both hands were obtained. RESULTS: The MR imaging criterion was periarticular contrast material enhancement of the wrists or the metacarpophalangeal and/or proximal interphalangeal joints in both hands. In the diagnosis of early RA, sensitivity and negative predictive value were both 100%, specificity was 73%, and accuracy was 89%. CONCLUSION: MR imaging is extremely useful in diagnosing early RA.

Adult↗

PubMed1996

Intracranial aneurysms: diagnostic accuracy of MR angiography with evaluation of maximum intensity projection and source images.

PURPOSE: To determine whether evaluation of source images from magnetic resonance (MR) angiography in addition to maximum-intensity projection (MIP) images improves the detection of aneurysms. MATERIALS AND METHODS: Conventional and MR angiography were performed in 193 patients with various intracranial vascular lesions or normal findings. Images were evaluated in a blinded manner. Two readings were performed 6 weeks apart by evaluating MIP images with and without source images. Results were evaluated with receiver operating characteristic analysis. RESULTS: Sensitivity for the detection of aneurysms increased slightly when source images were included. The detection rate of internal carotid artery aneurysms was most improved with the addition of source images. No statistically significant differences in performance were found between the readings with MIP images alone and with source images. CONCLUSION: Sensitivity may improve with combined reading of nonselective MIP and source images.

Case-Control Studies↗

PubMed1996

Overexpression of occludin, a tight junction-associated integral membrane protein, induces the formation of intracellular multilamellar bodies bearing tight junction-like structures.

Occludin is an integral membrane protein localizing at tight junctions with four transmembrane domains. When chicken occludin was overexpressed in insect cells by recombinant baculovirus infection, peculiar multilamellar structures accumulated in the cytoplasm. Partial isolation of these structures indicated that the introduced chicken occludin was highly enriched in these structures. Thin section electron microscopy revealed that each lamella was transformed from intracellular membranous cisternae whose luminal space was completely collapsed, and that in each lamella, outer leaflets of opposing membranes appeared to be fused with no gaps, like tight junctions. Furthermore, in the freeze-fracture replicas of these multilamellar structures, short tight junction-like intramembranous particle strands were occasionally observed, which were specifically labeled by anti-occludin mAb. These observations favor the idea that occludin plays a key role in the formation of tight junctions.

Animals↗

PubMed1996

Occludin is a functional component of the tight junction.

Occludin's role in mammalian tight junction activity was examined by 'labeling' the occludin pool with immunologically detectable chick occludin. This was accomplished by first transfecting MDCK cell with the Lac repressor gene. HygR clones were then transfected with chick occludin cDNA inserted into a Lac operator construct. The resulting HygR/NeoR clones were plated on porous inserts and allowed to form tight junctions. Once steady state transepithelial electrical resistance was achieved, isopropyl- beta-D-thiogalactoside was added to induce chick occludin expression. Confocal laser scanning microscopy of monolayers immunolabeled with Oc-2 monoclonal antibody revealed that chick occludin localized precisely to the preformed tight junctions. When sparse cultures were maintained in low Ca2+ medium, chick occludin and canine ZO-1 co-localized to punctate sites in the cytoplasm suggesting their association within the same vesicular structures. In low calcium medium both proteins also co-localized to contact sites between occasional cell pairs, where a prominent bar was formed at the plasma membrane. Chick occludin was detectable by western blot within two hours of adding isopropyl- beta-D-thiogalactoside to monolayers that had previously achieved steady state transepithelial electrical resistance; this coincided with focal immunofluorescence staining for chick occludin at the cell membrane of some cells. A gradual rise in transepithelial electrical resistance, above control steady state values, began five hours after addition of the inducing agent reaching new steady state values, which were 30-40% above baseline, 31 hours later. Upon removal of isopropyl- beta-D-thiogalactoside chick occludin expression declined slowly until it was no longer detected in western blots 72 hours later; transepithelial electrical resistance also returned to baseline values during this time. While densitometric analysis of western blots indicated that the presence of chick occludin had no detectable effect on E-cadherin or ZO-1 expression, the possibility cannot be excluded that ZO-1 might be a limiting factor in the expression of chick occludin at the cell surface. To test whether expression of chick occludin affected the process of tight junction assembly, monolayers in low Ca2+ medium were treated with isopropyl- beta-D-thiogalactoside for 24 or 48 hours, before Ca2+ was added to stimulate tight junction assembly. Chick occludin did not alter the rate at which transepithelial electrical resistance developed, however, steady state values were 30-40% above control monolayers not supplemented with the inducing agent. By freeze fracture analysis, the number of parallel tight junction strands shifted from a mode of three in controls to four strands in cells expressing chick occludin and the mean width of the tight junction network increased from 175 +/- 11 nm to 248 +/- 16 nm. Two days after plating confluent monolayers that were induced to express chick occludin, mannitol flux was reduced to a variable degree relative to control monolayers. With continued incubation with the inducing agent, mannitol flux increased on day 11 to 50%, and TER rose to 45% above controls. Both of these changes were reversible upon removal of isopropyl- beta-D-thiogalactoside. These data are consistent with the notion that occludin contributes to the electrical barrier function of the tight junction and possibly to the formation of aqueous pores within tight junction strands.

Animals↗

PubMed1996

Molecular dissection of tight junctions.

In epithelial and endothelial cells, the tight junction (TJ) seals cells to create a primary barrier to the diffusion of solutes across the cell sheet, and it also works as a boundary between the apical and basolateral membrane domains to create their polarization. An integral membrane protein working at TJ is postulated to exist, but it has remained elusive for quite some time. Most recently, using mAbs, we identified an integral membrane protein named occludin that was exclusively localized at TJ both in epithelial and endothelial cells. Here we overview our recent studies on the structure and function of occludin.

Animals↗

PubMed1996

Involvement of (n-6) essential fatty acids and prostaglandins in liver lipid accumulation in Japanese quail.

OBJECTIVE: To investigate the involvement of (n-6) essential fatty acids, such as linoleic acid [18:2(n-6)] or gamma-linolenic acid [18:3(n-6)], and of prostaglandins on liver lipid accumulation in Japanese quail. DESIGN: Effects of graded amounts of aspirin, which inhibits prostaglandin synthesis, on liver weight were determined in experiment 1. Experiment 2 was designed to clarify the effect of dietary essential fatty acid sources and inhibition of prostaglandin synthesis on the liver fat and fatty acid profile. ANIMALS: Female Japanese quail. PROCEDURE: In experiment 1, from 1 to 3 weeks of age, birds were fed ad libitum the essential fatty acids-free or linoleic acid-adequate (2%) diets with graded amounts of aspirin (0, 0.1, 0.2, and 0.4%). In experiment 2, from 1 to 4 weeks of age, birds were fed the same amount of essential fatty acids-free, linoleic acid-adequate, or gamma-linolenic acid (0.4%) diets with (0.2%) or without aspirin. RESULTS: In experiment 1, in groups given the essential fatty acids-free diet, liver weight increased with an increase in dietary aspirin concentration. In experiment 2, gamma-linolenic acid completely prevented liver triacylglycerol and cholesterol accumulation induced by the essential fatty acids-free diet. Aspirin treatment significantly lowered plasma prostaglandin F2 alpha concentration, but did not affect liver lipid concentrations. In groups fed the essential fatty acids-free diets, however, aspirin treatment increased liver weight and liver triacylglycerol concentration by 20 and 40%, respectively. CONCLUSIONS: gamma-Linolenic acid or its metabolites, but not linoleic acid itself, are important factors in reducing fatty liver in Japanese quail with the essential fatty acids-deficient condition.

Animals↗

PubMed1996

[Unilateral dissection of the cervical portion of the internal carotid artery and ipsilateral multiple cerebral infarctions caused by suicidal hanging: a case report].

This paper presents a case of traumatic dissection of the unilateral internal carotid artery of the cervical portion caused by hanging. A 63-year-old man attempted suicide by hanging and was rescued immediately after. No neurological deficits were detected for the first 4 hours. But then, right hemiplegia, aphasia and disturbed consciousness suddenly developed. On the 2nd day, MRI revealed multiple infarctions in the left cerebral hemisphere. MR angiography demonstrated severe stenosis at the cervical portion of the left internal carotid artery due to dissection. The left middle cerebral artery was not demonstrated. The patient was conservatively treated with fibrinolytic agents and regained consciousness gradually. But aphasia and right hemiplegia remained. During the next few weeks, the stenosis at the ICA slightly improved and the MCA was completely recanalized. Extracranial Doppler sonography revealed chronological hemodynamic changes of mean flow velocity and pulsatility index at the proximal and distal portion of the ICA stenosis.

Carotid Artery Diseases↗

PubMed1996

[Putaminal abscess occurring at the site of hemorrhage: a case report].

Brain abscesses following stroke have been reported only rarely. We presented a case of putaminal abscess following putaminal hemorrhage. The patient was admitted to our hospital because of acute onset of left hemiplegia. The size of the hematoma was medium and the patient was conservatively treated. In about two months after the ictus, he became intermittently febrile and laboratory examinations suggested the presence of general infections including meningitis. Meanwhile, CT and MRI revealed clearly abscess formation at the site of the hematoma with remarkable brain edema. Cerebrospinal fluid analysis showed the findings of meningitis. On diagnosis of brain abscess, stereotactic exploration was performed and pus mixed with old blood was aspirated. Bacteriological study of the specimen demonstrated Morganella morganii. Postoperative course was uneventful and the abscess cavity gradually subsided following drainage and irrigation of the abscess cavity.

Brain Abscess↗

PubMed1996

[CT findings of the irradiated intestinal wall: comparison of early vascular phase and delayed equilibrium phase].

The intestinal walls of the irradiated pelvic tumor cases of 20 patients were studied. CT manifestations of the irradiated intestinal wall were examined at the early vascular phase (examined 40 seconds after the injection of contrast medium by helical scan) and at the delayed equilibrium phase (examined 4 to 5 minutes after the injection of contrast medium by rapid sequence scan). Two characteristics were identified: intestinal wall thickening and a three-layered pattern. The former was better depicted on equilibrium phase, whereas the latter was clearer on early vascular phase. Differences in visualization of the wall thickening on vascular phase and delayed phase were statistically significant. The three-layered pattern was considered to suggest severe inflammatory edematous change of the intestinal wall. Early enhancement of the mucosal and muscular-serosal layers with less enhancement of the submucosal layer, and homogeneous distribution of the contrast medium to the interstitium on delayed phase were considered to be the reason.

Adult↗

PubMed1995

The interaction of clonidine and nitric oxide on feeding behavior in the chicken.

Central administration of alpha 2-receptor agonists stimulate food intake in mammalian and avian species. Recently we reported that inhibition of nitric oxide (NO) synthase (NOS) decreased food intake in chickens. In the present study, we investigated whether the increased eating induced by clonidine (Clon), an alpha 2-receptor agonist, is attenuated by NOS inhibition. In the first experiment, four levels (0, 9.4, 18.8 or 37.5 nmol/10 microliters) of Clon were administered into the right lateral ventricle of chickens, and food intake was monitored. Clon increased 30 min-food intake in a dose-dependent manner. In a co-administration study of L-NG-nitro-arginine methyl ester HCl (LNNA), a NOS inhibitor, and Clon, LNNA (0, 1.5, 3.0 or 5.9 mumol) attenuated food intake induced by Clon (37.5 nmol) in a dose-dependent manner. Our results suggest the possibility that NO interacts with adrenergic neurons in the central nervous system to modulate feeding behavior in the chicken.

Animals↗

PubMed1995

Factors influencing the intestinal phase of pancreatic exocrine secretion in the turkey.

The present study was done to investigate the factors regulating the intestinal phase of exocrine pancreatic secretion in the turkey. The intestine of turkeys equipped with pancreatic fistulas was perfused with peptone solution, fat emulsion and hydrochloric acid (HCl), and pancreatic flow and protein output were measured. Neither peptone solution nor fat emulsion had any effects on pancreatic secretion. HCl enhanced the flow rate of pancreatic juice but not protein output. To clarify the neural mechanism of this phenomenon, the vagal postganglionic blocker atropine was continuously infused and pancreatic secretion in response to intestinal HCl was measured. Atropine completely suppressed both pancreatic flow and protein output. It is suggested that the avian intestinal phase of pancreatic secretion is mainly controlled by cholinergic action though HCl stimulation.

Animals↗

PubMed1995

The regulation of gastrin secretion in the chicken.

Chicken gastrin has a C-terminal sequence resembling mammalian cholecystokinin, but its biological properties resemble mammalian gastrin. The mechanisms controlling chicken gastrin release are poorly understood. We have investigated the factors which influence chicken gastrin secretion in vivo. Plasma gastrin concentration was decreased within 12 h of fasting, but tissue gastrin concentrations were not significantly changed even after 24 h of food deprivation. In birds fasted for 24 h and treated with the H+/K(+)-ATPase inhibitor, omeprazole, plasma gastrin concentration was greatly enhanced indicating the importance of acid inhibition of the gastrin cell. It is well established that amino acids (particularly aromatics like Phe and Trp) and peptides stimulate gastrin release in mammals. In chicken, however, Met, His and Arg were the strongest stimulant amongst the essential amino acids investigated. Of these three amino acids, Met rapidly stimulated gastrin release. The GRP antagonist M216140 did not suppress the Met-induced gastrin release, suggesting that Met did not stimulate GRP release. Aromatic amino acids did not strongly influence gastrin release. Medium chain triacylglycerol, which is rapidly hydrolyzed to fatty acids in the lumen, strongly stimulated gastrin secretion but long chain triacylglycerol had no effect. The data suggest that amino acids (Met, Arg and His) and fatty acids, but not triacylglycerol, are gastrin releasing factors in birds while acid inhibits secretion: there are therefore both similarities and differences between birds and mammals in the control of gastrin release.

Animals↗

PubMed1995

Inhibition of food passage by omeprazole in the chicken.

The effect of omeprazole, a proton pump inhibitor, on the forward passage of the crop contents of chicks receiving 20% medium chain or long chain triacylglycerol was studied. Medium chain triacylglycerol significantly delayed the crop emptying of chicks compared with long chain triacylglycerol. Omeprazole also significantly inhibited passage from the crop of the long chain triacylglycerol meal. Application of omeprazole induces achlorhydria and consequently hypergastrinemia but chicken gastrin lower than 100 nmol/kg did not delay crop emptying. The addition of hydrochloric acid (HCl) to the diet reversed the action of omeprazole on the crop emptying of chicks. We conclude, then, that omeprazole delayed the crop emptying in chicks as a consequence of inhibition of acid secretion, although the mediator is not gastrin.

Animals↗

PubMed1995

Cholestyramine alters the lipid and energy metabolism of chicks fed dietary medium- or long-chain triacylglycerol.

The effects of cholestyramine, a bile acid binding polymer, on the lipid and energy metabolism of chicks given dietary medium-chain triacylglycerol (MCT) or long-chain triacylglycerol (LCT) were investigated. Chicks (from 8 to 17 days of age) were fed diets containing MCT or LCT at 200 g oil/kg diet with or without 2% cholestyramine under equalized feeding conditions. An adjusted LCT diet was formulated in order to supply another group with daily nutrients and dietary metabolizable energy (ME) equal to MCT groups, except for corn starch. ME intakes of chicks given MCT or LCT diets were reduced by cholestyramine; consequently, fat and energy retention was reduced, though the reduction was more drastic in chicks fed LCT. This was caused by a change in amounts of the fecal excretion of fat and bile acids. Cholestyramine enhanced the excretion of octanoic acid (8:0) in the feces, which suggests that bile acids are needed for 8:0 absorption. Cholestyramine affects the utilization of dietary MCT and LCT by lowering fat and energy retention in chicks. However, the effect of cholestyramine on MCT utilization was smaller than its effect on utilization of LCT.

Animals↗

PubMed1995

Role of dietary gamma-linolenic acid in liver lipid metabolism in Japanese quail.

1. The importance of linoleic acid (18:2n-6) itself and of dietary gamma-linolenic acid (18:3n-6) as essential fatty acids (EFA) in Japanese quail were investigated with regard to liver lipid metabolism. Experimental diets were made by adding of 0, 2 or 4 g gamma-linolenic acid/kg, or 20 g linoleic acid/kg to an n-6 EFA-free diet. From 3 to 6 weeks of age, birds were fed equal amounts of experimental diets. 2. Liver weight and lipid content in birds fed the 2 and 4 g gamma-linolenic acid/kg diet were significantly lower than those in birds fed the gamma-linolenic acid-free diet. However, no significant difference was observed between the gamma-linolenic acid- and linoleic acid-supplemented diets. 3. In birds fed the 4 g gamma-linolenic acid/kg diet, the proportion of arachidonic acid in the liver lipid was similar to that in quail fed the 20 g linoleic acid/kg diet, implying a conversion rate from linoleic acid to gamma-linolenic acid of approximately 20% of whole body content. 4. It is concluded that linoleic acid itself is not essential for Japanese quail and that at least 2 g/kg of gamma-linolenic acid in the diet completely prevents liver enlargement accompanied by lipid accumulation.

Analysis of Variance↗