Biomedical subjects

M Mato

Publications and source records attributed to M Mato.

At least 37 records · Page 2Linked to original sources

PubMed1993

Age-related changes in the microvessels of the human stomach: an ultrastructural study.

The ultrastructure of microvessels in the gastric mucosa of patients with atrophic gastritis was investigated. In the gastric mucosa of atrophic gastritis, the endothelial cells of microvessels were irregularly swollen and subendothelial spaces were enlarged. The basement membrane underlying the endothelium was thickened. Degeneration of smooth-muscle cells was also evident in the media. These changes appear to correspond to sclerosis or aging of the microvessels. Such sclerotic changes in microvessels may initiate deterioration of the microenvironment in the gastric mucosa and may consequently affect metabolic activity of the gastric mucosal cells. Those sequences might induce degeneration or abnormal differentiation of mucosal cells. Such vascular changes may advance slowly and increase in intensity with advancing age. The final result would be the histologic changes associated with atrophic gastritis.

Aged↗

PubMed1993

Histologic differentiation and motility of rat stomach.

An ultrastructural and immunohistochemical study was done to investigate the normal developmental process of rat gastric wall. Neuronal processes were observed on the external side of immature muscle cells on gestational day 15, and Auerbach's plexus was found on gestational day 18, after which neuronal elements extended just under the subepithelial area. Myofilaments appeared in undifferentiated mesenchyme cells on gestational day 15. On day 17, stomach was responsive to Ach stimulation. On the day after the initiation of gastric motility, gastric glands started to form on the mucosal surface. At the same developmental stage, some parts of the mucosal epithelium and the submucosal connective tissues were stained with antiserum against tenascin. Endocrine and parietal cells appeared in the mucosal epithelium on gestational day 19. Dense secretory granules on the apical surface of mucosal epithelium were increased between day 20 and 21. The cytoplasmic organelles gradually developed with advancing fetal age. We suggest that tenascin may play a role in gastric gland formation and that there are some relationships between gastric gland formation and gastric motility. We believe that the development of subepithelial tissues may be closely associated with epithelial growth.

Animals↗

PubMed1992

Cytoprotection by 16,16-dimethylprostaglandin E2. Role of gastric juice and mucus gel layer.

A mechanism of cytoprotection by 16,16-dimethylprostaglandin E2 (16,16-dimethyl-PGE2) was investigated in rats with respect to possible roles of the gastric juice and the mucus gel layer. 16,16-Dimethyl-PGE2 significantly increased the volume of gastric juice and mucus thickness. In a gastric juice-emptied stomach, 16,16-dimethyl-PGE2 protected the gastric mucosa against 30% ethanol, but not against 40% ethanol. Moreover, this agent did not show any cytoprotective action even against 30% ethanol when both gastric juice and mucus gel were removed. In this situation there was no histological change in the depth of injury, whether 16,16-dimethyl-PGE2 was given as pretreatment or not. These results suggest that there are two mechanisms that may play major roles in the cytoprotection of the gastric mucosa by 16,16-dimethyl-PGE2: (a) dilution of necrotizing agents by increased gastric juice and (b) thickening of the mucus gel layer.

Animals↗

PubMed1990

[Cytoprotection by 16,16-dimethyl prostaglandin E2--role of gastric content and mucus gel layer].

The mechanism of cytoprotection by prostaglandins (PGs) is still unknown, although many hypotheses have been proposed. We postulated a hypothesis that increased gastric content and thickened mucus gel layer by PGs may protect the gastric mucosa against damage from necrotizing agents. Two series of experiments were performed on Wistar male rats, weighing 250-300 g. (1) 16,16-dimethyl prostaglandin E2 (dmPGE2) in doses of 20 micrograms/kg was given orogastrically. Fifteen minutes later, the stomachs were emptied and/or the mucus gel layer removed, and several concentration of ethanol applied. After ten minutes, the stomachs were removed and lesions of the gastric mucosae were evaluated macroscopically and histologically. (2) Volume and pH of the gastric content and mucus thickness were measured 15 minutes after dmPGE2 administration. DmPGE2 did not protect the gastric mucosa against 40% ethanol in the emptied stomach. This agent had no cytoprotective action on the emptied and mucus gel-removed stomach in 30% ethanol application. These results had no significant difference with control group (saline 1 ml p.o.) about the extent of erosion. In histological study of the erosive region by scanning and light microscopy, we also found no differences in the depth of erosion between dmPGE2 group and control. In addition, dmPGE2 increased the gastric volume and mucus thickness significantly. These data suggest that following two effects by PGs play major role in cytoprotection of the gastric mucosa; (1) dilution of necrotizing agents by increased gastric content, and (2) thickening of the mucus gel layer.

16,16-Dimethylprostaglandin E2↗

PubMed1990

[Studies of age-related changes in intracerebral small vessels of rat--do all cerebral blood vessels get aging concurrently?].

Age-related changes of intracerebral small blood vessels were studied with light and electron microscopes. In the first step of this investigation (Experiment 1), Wistar rats of 4-month-old were employed to determine the appropriate concentration of administrated HRP (horseradish peroxidase) for surveying the uptake capacity of HRP. Each rat was injected HRP intravenously under light anesthesia with ether. After 30 minutes, rat brains were excised and prepared for stretch specimen (Mato et al, 1979). Light microscopically, corresponding with decrease of the concentration of injected HRP, the reaction products of HRP in the cytoplasm of fluorescent granular perithelial (FGP) cells reduced linearly and the injection of 5 mg HRP revealed only FGP cells in the parietotemporal region of cerebral cortex. Referring to the results mentioned above, 10 mg of HRP was decided to be applicable dose for the following study. In the next experiment (Experiment 2), Wistar rats of 4-month-old, 1.7-year-old and 2.4-year-old were used for the study on the relation between morphological alteration of vascular cells and changes of uptake capacity of FGP cells in aging. At 30 minutes after the injection of 10 mg, rats were perfused and fixed with 2.5% glutaraldehyde and 2% paraformaldehyde under light anesthesia. Then, rat brains were removed and divided coronally into three parts. After slicing with Vibratome, number and distribution of FGP cells were studied under light microscope. The other specimens were dehydrated and embedded in Epon 812. The ultrastructure of vascular cells (endothelial and smooth muscle cells) and FGP cells at each age was examined with JEM 2000 EX electron microscope. Supplementary, ultrastructure of middle cerebral and retinal arteries of 2.4-year-old rats was also studied for comparison with that of the intracerebral (cortical)small vessels. The findings obtained from Experiment 2 could be summarized as follows; 1. Light microscopically, in 4-month-old and 1.7-year-old rats, FGP cells including positive granules of HRP were often recognizable along small blood vessels of cerebrum, especially in cerebral cortices. In 2.4-year-old rats, the numbers of FGP cells with positive granules of HRP decreased significantly (p less than 0.01). It was confirmed that the uptake capacity of FGP cells reduced with aging. But, exceptionally, regardless from aging of animals, FGP cells belonging to a few special vessels in the parietotemporal area of cerebral cortices included many and intense reaction products. 2. Electronmicroscopically, the vascular cells changed in appearance and contents with aging.(ABSTRACT TRUNCATED AT 400 WORDS)

Aging↗

PubMed1989

Studies on the vasculogenesis in rat cerebral cortex.

The cerebral cortices are nourished by blood circulating through a capillary network branching from parent arteries. In this paper, vasculogenesis of the cerebral cortices in developing rats (11-18 days after birth) was studied by light and electron microscopy after intravenous administration of horseradish peroxidase (HRP). In the first phase of vasculogenesis, tentacles grew out from the distal end of the vascular cord (tip cells), and in the second phase, they extended to the afferent blood vessel. The reaction product of HRP was distributed not only in the primitive vascular lumen, but also in the peripheral extravascular space of the vascular cord. Most tentacles were free from reaction product, but, in some cases where reaction product was detected, the intercellular spaces had spread into the tip cells and reached the root of the tentacles. After the tentacles contacted the afferent vascular cord, the two vascular cords approached and fused with each other. Blood serum was able to circulate between the two vascular cords via the irregular interstices formed among the endothelial cells, cytoplasmic processes, and tentacles. Later, the primitive vascular lumen developed to a sufficient size to allow for the circulation of blood cells. The sequential events in the process of fusion between two vascular cords are illustrated. The following two points were also noticed in this study: 1) during cerebral vasculogenesis, degeneration and vacuolization in primitive endothelial cells occurred only in some of the serial sections and did not play a significant role in the formation of vascular lumen, and 2) cerebral pericytal macrophages (CPM) (classified as fluorescent granular perithelial cells by the authors) appeared close to the vascular cord, although the biological meaning of it remained unknown in the present investigation.

Animals↗

PubMed1989

[Role of perivascular phagocyte (FGP) of cerebral small blood vessel in cerebral edema].

Small cerebral blood vessels are provided with slender phagocytic cells which were designated as FGP (fluorescent granular perithelial) cells from their localization and property. They were derived from pial cells and became potent in the uptake capacity for exogenous substance about at one week after birth. The present study aims to confirm the role of FGP cells and to clarify morphological changes of them in cerebral edema. Cerebral cortices of Wistar rats received head injury (caused with dry ice) were studied electron microscopically at 0.5, 2, 5, 10, 16, 30, 48 and 72 hours after the injury. At the same interval, HRP (horseradish peroxidase) was injected intravenously for the demonstration of uptake capacity of FGP cells. The authors' attention focused on the change of ultrastructure of vascular wall including perivascular phagocytic FGP cell around small blood vessels and on the uptake capacity of FGP cells at each time. From 2 to 5 hours after the cold injury, pinocytotic vesicles often appeared in endothelium and smooth muscle cells, and blood plasma infiltrated into the perivascular space and was taken in the FGP cells. The FGP cells in control were provided with intense round inclusion bodies and looked moderately intense. However, the FGP cells in the experimental animals after the injury became swollen and vacuolized following the fusion of inclusion bodies and breakdown of their limiting membrane and looked pale owing to presence of vacuoles. Under this condition, the uptake capacity of FGP cells for HRP decreased remarkably, and ACPase which was confined to the inclusion bodies in controls spread diffusely into cytoplasm.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1988

Choline acetyltransferase immunopositive pyramidal neurons in the rat frontal cortex.

The putative cholinergic neurons of the rat's frontal cortex (Krieg's area 10) were studied using monoclonal antibody to choline acetyltransferase (ChAT). This paper reports two novel findings which might be very important to reason the function of the frontal cortex. Firstly, the immunopositive cells were distributed in layers II, IV, V and VI around the rostral half, and layers IV, V and VI around the caudal half of Krieg's area 10. Secondly, the majority of immunopositive neurons in layer V was pyramidal cell.

Animals↗

PubMed1986

Tridimensional observation of fluorescent granular perithelial (FGP) cells in rat cerebral blood vessels.

The tridimensional appearance and distribution of FGP (fluorescent granular perithelial) cells was studied by means of light and scanning electron microscopy. In young rats they first appeared as hexagonal cells in that were closely associated; later they transformed into slender forms and were loosely arranged. Scanning electron microscope observation gave a general view of FGP cells, their globular vacuolated inclusions, and their hypertrophied protrusion into the luminal surface of blood vessels. The nodular protrusions may be related to the limitation of blood flow in small cerebral blood vessels.

Animals↗

PubMed1986

Serological determinants of fluorescent granular perithelial cells along small cerebral blood vessels in rodent.

As reported previously, the perivascular cells laden with fluorescent granules (FGP cell) are situated in Virchow-Robin space and show marked uptake capacity for intraventricularly administered substances. The phagocytic FGP cells are derived developmentally form leptomeningeal cells and are recognizable in various kinds of animals, including humans. In the present paper, the FGP cells of rodents are studied by immunological techniques. It is clearly demonstrated that rat FGP cells express the antigenic determinant for Ia antibody at about 7 days after birth, and also that mouse FGP cells show a positive reaction against mouse Fc and splenic macrophage antibodies at about the same developmental stage. The specific determinants of FGP cells appear concurrently with the initiation of horseradish peroxidase uptake. On the other hand, Ia antigen is also shown in subarachnoid macrophages, but not in immature FGP cells, endothelium and pericyte. Based on these findings, it seems reasonable to consider that the FGP cells are indigenous cerebral macrophages and significant for the local immune response in a cerebral tissue. Further, in this paper, to prevent confusion of the FGP cell with the other perivascular cells, the authors propose designating the FGP cell as Mato cell.

Aging↗

PubMed1985

An attempt to differentiate further between microglia and fluorescent granular perithelial (FGP) cells by their capacity to incorporate exogenous protein.

It seems established that under pathological conditions, microglia and blood monocytes (invading the cerebral parenchyma) behave as histiocytic cells in the central nervous system. However, it has not been clear whether or not phagocytic cells are present in normal cerebral tissue. Recently, we found a new type of cell having an uptake capacity for exogenous substance at the bifurcations of small cerebral vessels except for capillaries. According to Imamoto et al. (1982), ameboid microglia, a kind of precursor of microglia, appear at a perinatal stage and can incorporate exogenous material. In the present paper, the developmental sequences of ameboid microglia and the unique cells laden with fluorescent granules are compared at a light and electron-microscopic level. From this study, it is clear that ameboid microglia are already present in the corpus callosum at 5 days after birth and are potent in their uptake capacity for horseradish peroxidase (HRP). However, at 2 weeks, they transform into star cells and the capacity for incorporation diminishes markedly. The finding is also supported by the quantitative analysis of transformation of ameboid microglia. At 3 months, glial cells do not take the administered HRP under the present conditions. On the other hand, fluorescent granular perithelial (FGP) cells arise from a leptomeningeal tissue (pia mater) and become situated in the perivascular spaces. They are not clearly defined at 5 days, and their uptake capacity for HRP has not yet developed. At 2 weeks, the FGP cells take definite forms with several inclusion bodies, and their uptake capacity for HRP attains a certain degree. Often, they are located at bifurcations of small blood vessels. At 3 months, the FGP cells differentiate completely in appearance, and their pinocytotic capacity reaches a high level. Consequently, the FGP cells belong to a different type of cell from that of ameboid microglia in their developmental sequences and assume a principal role of scavenging waste products in normal cerebral tissue.

Animals↗

PubMed1985

Unusual intracytoplasmic lamellar bodies in a malignant gonadal stromal tumor.

Characteristic intracytoplasmic lamellar bodies were found in a malignant gonadal stromal tumor. These bodies consisted of the stacks of up to 200 tubular cisternae arranged in parallel. Each cisterna had a circular section in tangential view and a diameter of about 85 nm. The cisternae on the outermost side of these lamellar bodies tended to be dilated and adorned with ribosomes. The ends of cisternae were often contiguous with rough-surfaced endoplasmic reticulum. The latter feature is also seen in annulate lamellae, but periodically spaced annuli or discontinuities characteristic of annulate lamellae were never observed. Furthermore, fine ribosomal granules resembling a rosary were recognizable along the whole circumference of the outer surface of each cisterna. The unique structure we describe is a cytoplasmic organelle which, like annulate lamellae, is closely associated with the endoplasmic reticulum and is presumed to be related to the genesis of rough-surfaced endoplasmic reticulum in tumor cells.

Adult↗

PubMed1985

[Studies on ultrastructural changes in perivascular cells (F.G.P.) of small cerebral vessels at the initial stage after cold injury--chronological observations on F.G.P. within 24 hours].

As the potentiated cells in reaction to cerebral edema and damage, microglia, astrocytes and macrophages had been listed. Recent neuropathological study elucidated that most of cerebral macrophages were derived from blood leucocytes including monocytes. Several years ago, one of the authors reported the presence of histiocytic cells in perivascular space and named them as fluorescent granular perithelial (F.G.P.) cells from their morphological characteristics. The present paper is concerned with the response of the F.G.P. cells to the vasogenic edema induced with cold injury. The animals employed were Wistar male rats aged 3 months. At 2, 6, 10, and 24 hours after the cold injury, cerebral cortex was excised, and specimens were prepared for light and electron microscopical observations. As already reported, the F.G.P. cells included autofluorescent and PAS positive granules. The intracellular granules were rich in hydrolytic enzymes and lack in sudanophile substances. The F.G.P. cells were derived from leptomeningeal cells and acquired uptake capacity for exo- and endogenous substance after birth. In this paper, the F.G.P. cells locating in the boundary between cold injured and healthy regions were observed. At 2 to 10 hours after cold injury, the F.G.P. cells were vacuolated and swollen, and the electron opacity of them decreased moderately. Lipoidal substance appeared in the intracellular granules first at 2 hours and then increased, while the activity of acid phosphatase in them became low in corresponding with a time interval after the cold injury. At this period, occasionally the F.G.P. cells possessed a complicated boundary to astrocytes surrounding them. In general, such morphological changes were reversible and recovered partially around at 24 hours.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1984

Evidence for the possible function of the fluorescent granular perithelial cells in brain as scavengers of high-molecular-weight waste products.

The fluorescent granular perithelium (FGP) of rats and humans under experimental and pathological conditions was examined with the electron microscope. The FGP incorporated high molecular-weight protein (ferritin) and carbon particles administered intraventricularly. In a case of spontaneous cerebral hemorrhage, the FGP was found to contain lipoidal products and minute fragmented cell debris. The FGP in a patient with lipidosis contained pale inclusion bodies. In aged individuals, the inclusion bodies formed irregular larger aggregates.

Aging↗

PubMed1983

Distribution and number of fluorescent granular perithelial cells in coronal sections of rats cerebrum.

The fluorescent granular perithelial cells (F.G.P.) of rats aged 1 week to 2 years were observed under a light microscope to investigate intracellular granules and localization. This study showed that a marked proliferation of F.G.P. occurs within 3 weeks after birth and the total number remains constant for 2 years. The F.G.P. are mainly distributed in the gray matter, and are scarce in the white matter. The number and distribution of F.G.P. seems to reflect a difference of vascularization and function in different cerebral regions.

Aging↗

PubMed1983

Behavior of fluorescent granular perithelium (FGP) in cerebral cortex of SHR-SP rats under some conditions.

The fluorescent granular perithelial cells (FGP) in control and experimental specimens of SHR-SP rats were studied with light and electron microscopes. The results obtained are as follows. The FGP in SHR-SP rats are localized along small cerebral vessels and provided with many irregularly shaped inclusion bodies. Their matrices are homogenous and relatively less dense. Sometimes, the FGP fall into degeneration and their cytoplasm shrinks and fills with small dense granules. Concomitantly, collagen fibers appear surrounding them. After feeding rats a fat-rich chow, lipoidal substances appear in intracellular granules of FGP at the light microscopical level. Electron microscopically, the FGP are swollen and their inclusion bodies vary in shape and content. Large inclusion bodies are composed of several middle-sized inclusion bodies with heterogenous matrices. Frequently, pale inclusion bodies are provided with intensely stained limiting membranes. These facts suggest an incorporation of fat into the FGP. With the administration of elastase, intracellular lipid decreases moderately and the FGP scarcely swell. The cytoplasm of FGP and the contents of inclusion bodies become defined and contrasty. From this evidence, elastase seems to facilitate a fat metabolism in FGP. Morphological and functional differences between FGP and other perivascular cells including pericytes, microglia, and mast cells are briefly discussed.

Animals↗

PubMed1982

Uptake of fat by fluorescent granular perithelial cells in cerebral cortex after administration of fat rich chow.

As reported previously, fluorescent granular perithelial cells (F.G.P.) are distributed along small blood vessels, possibly postcapillary venous vessels, in the cerebral cortex; these cells take up intraventricularly administered horseradish peroxidase efficiently. In this study it is shown that lipid substances of the blood are easily incorporated into F.G.P. and stored in their cytoplasm. The quantity of fat deposits in F.G.P. varies with the age of the animal and is very marked in old rats. The administration of elastase suppresses the fat uptake and/or facilitates the fat metabolism in F.G.P.

Aging↗

PubMed1982

Ultrastructural observation on the tips of growing vascular cords in the rat cerebral cortex.

The distal ends of vascular cord in the cerebral cortex are investigated electron microscopically in rats at the 13th postnatal day. The tip of the vascular cord consists of central cuboidal cells (primitive endothelial cells) and surrounding flat cells (primitive pericytes), and has no lumen. The primitive endothelial cells (tip cells) possess several long tentacles which contain only fibrous structures and extend through the neuropile.

Animals↗