[Hemostatic drugs in a patient with antiphospholipid syndrome and clinically significant perioperative bleeding].
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Adult↗
Biomedical subjects
M Mato
Publications and source records attributed to M Mato.
[Dexmedetomidine, a promising drug].
Surgical patients and others admitted to recovery and intensive care units require sedation and pain therapy, for which a range of pharmaceuticals is available. Their use is more or less widespread, but other drugs, such as dexmedetomidine, have been and continue to be studied for application in such patients. Dexmedetomidine, a compound derived from imidazole, has a high affinity for the alpha-2 adrenoreceptor, on which it acts as a potent agonist. A large number of laboratory and animal studies have been performed, as have clinical trials enrolling healthy volunteers or patients with the aim of shedding shed light on the main pharmacological features of dexmedetomidine. As a result, dexmedetomidine is known to have sedative, hypnotic and analgesic properties. It diminishes the need for other anesthetics and sympathicolytics, and it reduces catecholamine release. Controlled clinical trials have looked at the use of dexmedetomidine in patients who require sedation and analgesia in postoperative intensive care units. Research shows that dexmedetomidine lowers the need both for other sedatives, such as propofol or midazolam, and for analgesic morphine. Moreover, its effect on ventilation is scarce. Dexmedetomidine is presently distributed in the United States but not in the European Union. The aim of this review was to outline the main pharmacological properties of dexmedetomidine, including its pharmacokinetics and pharmacodynamics, to give an overall view of this promising drug.
Adrenergic alpha-Agonists↗
[Incidence of postoperative shivering in relation to the time of sevoflurane discontinuation].
OBJECTIVES: We aimed to determine whether early termination of sevoflurane administration lowers the incidence of postanesthetic shivering. MATERIAL AND METHODS: Eighty ASA I-III patients were randomized to two groups of 40 (Group A and Group B). All were premedicated with oral bromazepam. Fentanyl (2 micrograms/Kg), propofol (2.5 mg/Kg) and atracurium (0.5 mg/Kg) were used for induction. Anesthesia was maintained with sevoflurane in 60% N2O in oxygen at 1 maximum alveolar concentration, with boluses of fentanyl and atracurium on demand. Sevoflurane administration was terminated 30 minutes before awakening in group A and 10 minutes before awakening in group B. After termination, 60% N2O in oxygen was used in both groups. Mean blood pressure, heart rate and peripheral and core temperatures were measured at 5 minutes intervals during surgery. Postoperative shivering was recorded until one hour after awakening. RESULTS: Patient characteristics and duration of anesthesia were similar in both groups. The incidence of shivering was significantly lower in group A (4%) than in group B (57%). No significant differences were observed in other variables. CONCLUSIONS: The important observation in this study was that the incidence of postoperative shivering in group A was lower than in group B and lower than the incidences reported in other similar studies.
Adult↗
[Paraplegia after left thoracotomy in a patient carrying an epidural catheter].
A 61-year-old man undergoing left thoracotomy, in whom a lumbar epidural catheter had been inserted, experienced paraplegia in the immediate recovery period. Diagnostic tests and clinical examinations ruled out neurological causes attributable to the catheter, indicating that the cause was surgical. Paraplegia after thoracotomy is rare but has been described in the literature. We discuss ways that injuries may produce medullary lesions related to thoracic surgery.
Analgesia, Epidural↗
Regional difference of lipid distribution in brain of apolipoprotein E deficient mice.
According to recent knowledge, apolipoprotein E (apo E) plays a significant role in the homeostasis of intracellular cholesterol level in various tissues. Apo E deficient mice develop hyperlipidemia, and suffer from atherosclerosis in extracerebral blood vessels and neurodegeneration in the central nervous system. Furthermore, Walker et al. (Am. J. Path., 1997;151:1371-1377) demonstrated cerebral xanthomas of various sizes in the brain of apo E deficient mice. In the present study, it is illustrated that in the homozygous apo E deficient mice of advancing age, a great number of foamy macrophages extravasate from microvessels in thalamus and fimbria hippocampi, and scatter in the perivascular regions and migrate toward the ependyma, fimbria hippocampi, hippocampus, and thalamus. Here, it must be pointed out that under hyperlipidemia, although foamy macrophages made clusters in the perivascular region, the cerebral microvessels did not develop atherosclerosis. On the other hand, in the other cerebral regions such as cerebral cortex, caudoputamen, globus pallidus, and substantia nigra, macrophages did not appear and microvessels retained normal shapes, but the fluorescent granular perithelial (in short, FGP) cells accompanied by these vessels contained a certain amount of lipids. That is, in the cerebral cortex and caudoputamen, lipid components are detected in FGP cells and microglia, while in the globus pallidus and substantia nigra, they are mainly localized in astrocytes. The reason why the astrocytes in such defined regions contain, specifically, a high quantity of lipid components remains unsettled. Axonal degenerations are often represented in thalamus, globus pallidus, and substantia nigra. On the other hand, in the specimens of Wild-type mice, lipid components were observed only in FGP cells, and the vascular architecture took a normal profile. Any lipid laden macrophages and the axonal degenerations could not be detected through the cerebral parenchyma. Furthermore, it is also a noticeable finding that immunohistochemically, the FGP cells express a positive reaction against the antibody of apo E in the Wild-type mice, but those of homozygous apo E deficient mice are immunonegative. FGP cells are not only provided with the scavenger receptor, but also contribute to the lipid metabolism in the brain.
Animals↗
[Ultrastructural study on intracerebral small blood vessels and fluorescent granular perithelial (FGP) cells in experimental cerebral ischemia].
In order to clarify the sequential changes of the morphology of vascular cells and FGP cells under cerebral ischemia, 32 male Wistar rats were employed. The FGP cells in the present paper are distributed along cerebral microvessels, and markedly potent in the uptake capacity for endo- and exogenous substances under the physiological and pathological conditions. Under the anesthesia of pentobarbital, experimental animals suffered from cerebral ischemia were produced by (1) occlusion of bilateral vertebral arteries, (2) unilateral ligation of common carotid artery accompanied with occlusion of vertebral arteries and (3) temporary clipping of bilateral common carotid arteries accompanied with occlusion of vertebral arteries. On 1 to 14 days after the treatments mentioned above, the cerebral cortices of animals were examined with the electron microscope with paying special attention to morphological changes of FGP cells. From the observation, it is confirmed that: (1) after occlusion of vertebral arteries (first group of experimental animals), the FGP cells become edematous without any severe damage of cerebral neurons through 2 weeks.: (2) In case of the unilateral ligation of common carotid artery (second group of experimental animals), the FGP cells and neurons tend to degenerate at the ligated side on 14 days, but at the opposite side, the considerable vacuolation and swelling of the FGP cells are evident, without accompanying with any degeneration of neurons and FGP cells, and: (3) In the reflow experiment (third group of experimental animals), the neurons are not affective and the FGP cells show some degenerative changes on 7 days, but most of them recovered on 14 days. From these observations, it may be concluded that the morphological changes of FGP cells run parallel with the change of microenvironment surrounding neurons, and the FGP cells, in addition to astrocytes, are reliable morphological markers of cerebral edema.
Animals↗
Immunohistochemical evidence for a macrophage scavenger receptor in Mato cells and reactive microglia of ischemia and Alzheimer's disease.
Macrophage scavenger receptors (MSR) are implicated in the development of atherosclerosis and amyloid b-protein deposition in Alzheimer's disease. However, histopathological studies of MSR expression in human tissues have been hampered by a lack of specific antibodies. Using MSR-deficient mice, we successfully raised a novel monoclonal antibody against human MSR together with high-titer antisera. These antibodies specifically recognized human tissue macrophages and human MSR protein purified from differentiated THP1 cells. In normal brain, MSR staining was mainly distributed to the perivascular cells, which correspond to Mato's fluorescent granular perithelial cells (Mato cells). In the lesions of ischemia and Alzheimer's disease, a subset of microglia stained positive for MSR. These novel antibodies are useful tools for analysis of MSR expression in human tissues.
Alzheimer Disease↗
Ultrastructural and immunohistochemical changes of fluorescent granular perithelial cells and the interaction of FGP cells to microglia after lipopolysaccharide administration.
Fluorescent granular perithelial (FGP) cells introduced by Mato et al. (1979, 1980, 1981) are situated in the Virchow-Robin space of cerebral microvessels and exhibit a marked uptake capacity for the endo- and exogenous materials in physiological conditions. That is, the FGP cells are the perivascular macrophage lineage enclosed by a basal lamina and glia limitans and are distributed between blood vessels and cerebral parenchyma. As reported previously, the FGP cells were distinguishable from microglia and pericytes in their morphology, location, and epitopes on their cytoplasmic membrane. On the other hand, it is established that microglia are upregulated by lipopolysaccaride (LPS) administration, but it remains unsettled whether the FGP cells, the perivascular macrophagic cells, are activated by LPS or not and what role the FGP cells play in the upregulation of microglia. Thus far, the morphological relationship between FGP cells and microglia in the process of upregulation has not been clarified. Thirty-six 7-month-old Wistar male rats were employed. The animals were sacrificed at 2, 5, 10, 24, and 72 h after the intravenous administration of 500 microg/kg of LPS. The FGP cells and microglia in their cerebral cortex were studied with immunohistochemical and electron microscopical techniques. The findings of the present study indicated that the majority of FGP cells were upregulated by LPS from the results of immunohistochemical and morphological data, but some of them tended to degenerate. Furthermore, in the time course after LPS administration, microglia were also upregulated and approached the microvessels and occasionally contacted the FGP cells directly. From these findings, it is hypothesized that FGP cells may significantly influence the mobilization and upregulation of microglia caused by LPS administration.
Animals↗
Isolation and characterization of a cDNA clone of UDP-galactose: flavonoid 3-O-galactosyltransferase (UF3GaT) expressed in Vigna mungo seedlings.
Four cDNA clones were isolated from Vigna mungo seedlings by the screening with cDNA encoding UDP-glucose:flavonoid 3-O-glucosyltransferase (UF3GT) of Antirrhinum majus as a probe; the product of the gene corresponding to one cDNA was more highly expressed in the first simple leaves than in stems. Nucleotide sequence analysis revealed 1,691 bp (including 326 bp non-reading) containing an open reading frame of 455 amino acids. The deduced amino acid sequence showed 42% and 23% identity with those of A. majus UDP-glucose:flavonoid 3-O-glucosyltransferase (UF3GT) and Petunia hybrida UDP-rhamnose:anthocyanidin 3-O-glucoside rhamnosyltransferase (RT), respectively. One region of the cDNA (amino acids 325 to 387) showed similarity to ceramide UDP-galactosyltransferases of mice, rats and humans. A crude extract from Escherichia coli, in which the protein was expressed from the cDNA, showed high UF3GaT activity but low UF3GT activity, and was similar in K(m), optimal pH and substrate specificity to UF3GaT from V. mungo. We conclude that we have obtained UDP-galactose:flavonoid 3-O-galactosyltransferase (UF3GaT) cDNA from V. mungo.
Amino Acid Sequence↗
[Perithelial cells around cerebral blood vessels].
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Animals↗
Growth retardation of Mato's fluorescent granular perithelial (FGP) cells in scavenger receptor knockout (SRKO) mice.
BACKGROUND: Mato's fluorescent granular perithelial (FGP) cells are situated between the basal lamina of cerebral microvessels and the glia limitans covering astrocytic processes. Because they are potent enough to take up endo- and exogenous substances in a steady state, they are regarded as scavenger cells in the central nervous system. The scavenger receptor for oxidized low-density lipoprotein (LDL) is also expressed on their cytoplasmic membrane. We studied the differentiation and growth of FGP cells in wild-type and scavenger receptor knockout (SRKO) mice. METHODS: Wild-type (129 strain) and SRKO mice at 1, 3, 5, 8, 10, 14, and 28 days after birth were employed in this study. Stretch specimens of their cerebral cortices were used for immunohistochemical investigations, and Epon-embedded specimens of the same region were studied with an electron microscope. RESULTS: In wild-type mice, perivascular cells derived from the pial tissue were transformed at approximately 8 days after birth into the FGP cells, which, provided with several epitopes common to macrophage lineages, developed over a period of 14 days. The FGP cells possessed several inclusions and were surrounded by two defined sheets of basal lamina and continuous glia limitans. At 4 weeks, their morphology, enzymatic activity, and epitopes advanced with the aging of the mice. However, in SRKO mice, at 8 days, the perivascular cells took fibroblastoid forms with scarce lysosomal inclusions, and, even at 14 days, glia limitans remained discontinuous and most of FGP cells remained immature in their cytoplasmic organelles. Different from the case with the wild-type, the intensity of the labeling of epitopes remained at a low level. At 4 weeks, some of the FGP cells fell into degeneration, and the others were differentiated to a certain degree. CONCLUSIONS: The development of Mato's FGP cells in SRKO mice was retarded in the morphology, enzyme activity, and epitopes. The scavenger receptor, which reacted with the antibody 2F8, seems to be closely associated with the development of Mato's FGP cells.
Acid Phosphatase↗
[Study on Mato cells (Mato's FGP cells) under various conditions].
Mato cells are unique macrophagic cells locating in the Virchow-Robin space of cerebral microvessels. They play a significant role in blood brain barrier, and uptake and digest proteinous and lipoidal materials derived from surroundings. They are provided with epitopes of macrophage lineages such as MHC Class II and scavenger receptor. Under pathological conditions, -cerebral injury, hypercholesteremia, hypertension and congenital dysfunction of nerve and some enzymes-induce heavy damages of Mato cells in shape and contents, and some of Mato cells are going into degeneration. Subsequently, the architecture of microvessels is also modified and result in the narrowing of vascular luminae. Finally, the authors discusses these findings referring to the earlier reports of Alzheimer (1913).
Aging↗
Involvement of specific macrophage-lineage cells surrounding arterioles in barrier and scavenger function in brain cortex.
The transport of solutes between blood and brain is regulated by a specific barrier. Capillary endothelial cells of brain are known to mediate barrier function and facilitate transport. Here we report that specific cells surrounding arterioles, known as Mato's fluorescent granular perithelial (FGP) cells or perivascular microglial cells, contribute to the barrier function. Immunohistochemical and in situ hybridization studies indicate that, in normal brain cortex, type I and type II macrophage scavenger receptors are expressed only in FGP/perivascular microglial cells, and surface markers of macrophage lineage are also detected on them. These cells mediate the uptake of macromolecules, including modified low density lipoprotein, horseradish peroxidase, and ferritin injected either into the blood or into the cerebral ventricles. Accumulation of scavenged materials with aging or after the administration of a high-fat diet results in the formation of honeycomb-like foam cells and the narrowing of the lumen of arterioles in the brain cortex. These results indicate involvement of FGP/perivascular microglial cells in the barrier and scavenger functions in the central nervous system.
Adult↗
Study on distribution of pericyte and fluorescent granular perithelial (FGP) cell in the transitional region between arteriole and capillary in rat cerebral cortex.
BACKGROUND: The FGP (fluorescent granular perithelial) cell nominated by M. Mato were distributed around small cerebral vessels and potent in the uptake capacity. They are provided with surface antigens related to macrophage lineage. The aim of this report is to show the regional distribution of pericytes and novel perivascular cells (FGP cell) in relation to the glia limitans and basal lamina. METHODS: The perietal cortex of rat cerebrum were fixed with a mixture containing 2.5% glutaraldehyde and 2% paraformaldehyde with or without 1% tannic acid and 1% osmium tetroxide buffered with 0.1 M phosphate. The specimens were embedded in Epon 812 and cut serially and observed with the light microscope. After selecting the appropriate region of blood vessels in the sections, they were reembedded in Epon 812 and were prepared for electron microscopic observation. RESULTS: Fixatives containing tannic acid gave good results for the discrimination between the glia limitans and the basal lamina at an electron microscopical level. The FGP cells were situated in the interstices between thick basal lamina of blood vessel and thin glia limitans of astrocyte (Virchow Robin space). In the terminal part of cerebral arteriole, the vascular basal lamina abutted against the glia limitans and both laminae were fused. The basal lamina enclosing pericytes was common to endothelium and the basal lamina of capillary was assumed to be the composite of proper basal lamina and glia limitans. Subsequently, the FGP cells surround only arteriole and venule, whereas the pericytes belong to capillaries. At the boundary of arterioles and capillaries, FGP cells coexisted with pericytes and were localized at the external site of pericytes bordering with basal lamina. CONCLUSIONS: Based on these findings, the FGP cells were different from pericytes in their localization and distribution. Some roles of FGP cells in cerebral metabolism are discussed.
Animals↗
The distribution of TM-316-associated surface antigen on polymorphonuclear leucocytes: an immunoelectron microscopic study.
It has been established that MoAb TM-316 recognizes an epitope on leucocytes and specifically inhibits the chemotactic behavior of leucocytes. In the present paper, the distribution of this epitope on the cell surface and in intracellular organelles was studied by immunoelectron microscopy. Leucocytes separated from the blood of healthy men and from synovial fluid from patients suffering from rheumatoid arthritis were used. They were fixed with a mixture containing paraformaldehyde, glutaraldehyde and picric acid. As the second antibody, goat anti-mouse IgM conjugated to 10 nm gold colloids was employed. In normal specimens, the epitope was found to some extent on the cytoplasmic membrane of neutrophilic leucocytes, but it was only sparsely distributed on eosinophilic and basophilic leucocytes. On activated neutrophilic leucocytes, obtained from the synovial fluid of rheumatoid arthritis patients, the immunolabeling was markedly increased. The number of sites where the epitope occurs on the surface of leucocytes is thus associated with the cell type, and also with the level of activation of the leucocytes. In order to investigate the processing of the antigen, the intracellular localization of the epitope in the neutrophilic leucocytes was also studied. The epitope recognized by TM-316 was also detected in/on the characteristic granules and Golgi stacks.
Antigens↗
Helicobacter pylori detected deep in gastric glands: an ultrastructural quantitative study.
To determine the presence of Helicobacter pylori deep in the gastric glands and in the parietal cell canaliculi, biopsied specimens from 15 patients were observed by electron microscopy. In the specimens, 818 H. pylori and 1,846 parietal cells were detected. Most of the H. pylori (93.9%, 768/818) were present on the mucosal surface. However, a few organisms (50/818, 6.1%) were detected deep in the mucosa. The mean number of H. pylori per specimen was 2.13 (32/818, 3.9%) and 1.20 (18/818, 2.2%), deep in the gland and in the parietal cell canaliculi, respectively. All appeared morphologically intact. Although the combination of culture and histology from biopsy tissues is usually used for isolation of H. pylori in most laboratories, such organisms are considered difficult to detect with conventional methods and to dislodge with antimicrobial therapy. Therefore, H. pylori present deep in the mucosa are suggested to be one of the factors in recrudescence after eradication therapy. In addition, H. pylori in the parietal cell canaliculi may affect parietal cell function or alter gastric physiology.
Adult↗
Morphological aspects of the cytotoxic action of Helicobacter pylori.
OBJECTIVE: To morphologically investigate the cytotoxic action of Helicobacter pylori on gastric mucosal cells. METHODS: Twenty biopsy specimens were obtained from the antrum and greater curvature of the upper body of the stomach, and examined by electron microscopy to elucidate the process of mucus cell injury induced by H. pylori. RESULTS: Only H. pylori colonies in intimate contact with the mucosal cells caused various cell alterations, including loss of microvilli, mucus depletion, cell membrane injury and degeneration of the cytoplasm. In contrast, H. pylori that were not in contact with the mucosa had no effect on the surface mucus cells. CONCLUSIONS: The results of this study suggested the following mechanism of H. pylori-induced gastric mucosal injury. Intimate contact between H. pylori and the epithelial cell is necessary for cytotoxic action. During the process of cytotoxic action, degradation of the mucous gel layer and the glycocalyx are first caused by the proteolytic enzymes produced by H. pylori. Then the microorganism approaches the surface mucus cell, making intimate contact with the cell surface. Finally, H. pylori adheres directly to the cell membrane, effecting direct action of the toxins on the cell membrane. Subsequently, the degenerative changes induced destroy the cell membrane, resulting in degeneration of the cell itself.
Bacterial Adhesion↗
[An experimental study on muscle regeneration--formation of myotubes and environment].
The repair of injured muscle is completed by a proliferation and differentiation of myogenic cells and myotubes. However, little is known about the microenvironment in which the formation of myotubes can proceed in vivo. We employed the polyvinyl alcohol (PVA) sponge model to investigate the milieu in which myotubes could be differentiated. Small pieces of PVA sponge were implanted after immersion in physiological saline into the gastrocnemius of adult Wistar rats as controls. In the experimental groups, before implantation, PVA were treated with basic fibroblast growth factor (FGF), type IV collagen, laminin and hydrocortisone. Newly-formed tissues within the PVA were examined immuno- and histochemically under light- and electronmicroscopy after 7 to 10 days implantation. Particular attention was focused on the formation of myofilaments in the migrating cells. From this study, it became clear that FGF, collagen and laminin accelerated the migration of mesenchymal cells into the PVA compared with controls. However, myotube formation could not be detected in either the experimental or control groups. But in the specimen treated with 10mg/ml hydrocortisone, myotubes appeared frequently in the migrating cells of PVA. A small amount of fibroblasts, macrophages and eosinophils were scattered around the myotubes and not clustered. They were provided with undefined basal lamina. Fibronectin and collagen fibers were also detected surrounding the myotubes. These findings suggested that, although the migration of satellite cells and the appearance of fibronectin are prerequisites for myotube formation, the most promising condition for myotube formation involved a suppression in the migration of the fibroblasts, macrophages and eosinophils. A certain concentration of steroids can therefore prepare a favorable microenvironment for this process.
Animals↗