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S Kida

Publications and source records attributed to S Kida.

At least 37 records · Page 2Linked to original sources
PubMed1997

Membranous ultrastructure of human arachnoid cells.

The ultrastructure of arachnoid cell membranes was investigated by conventional transmission EM and by freeze-fracture techniques in human arachnoid granulations. Arachnoid cells showed widespread membrane specialization in the granulations including the formation of desmosomes, gap junctions, tight junctions, intermediate junctions, hemidesmosome-like structures, and micropinocytotic vesicles. However, the extent of the specialization varied from portion to portion; this was clearly shown on freeze-fracture replicas. Numerous extracellular cisterns were separated by cytoplasmic bodies or slender processes, joined by these junctional complexes. Uncoated and coated vesicles were abundant along the surface of extracellular cisterns representing the pathway of CSF. Complexes of branching tight junctions were comprised of 1-50 particle strands, which formed elaborate meshworks accompanied by numerous gap junctions and desmosomes. Micropinocytotic vesicles were often concentrated in the arachnoid cell cluster up to 40 per microm2, which is equivalent to the concentration in brain capillary endothelial cells. The results of this study clearly suggest that arachnoid cells in arachnoid granulations are not only tightly adherent to form a firm structure for the passage of CSF, but that the arachnoid cells lining the CSF pathway show intense cell-cell communication and pinocytotic activity. This high transcellular activity probably reflects active transports or secretion of certain molecules by arachnoid cells.

Adolescent↗
PubMed1997

[Immunologic significance of lymphatic drainage of the brain].

Despite the evidence for immunological reactions in the human CNS, in viral encephalitis and in multiple sclerosis, connections between the brain and the immune system are poorly understood. In rodents, tracers injected into the interstitial fluid of the brain drain to the cervical lymph nodes by perivascular pathways in the brain and nasal lymphatics. Similar pathways could serve as lymphatics in the human brain. In the present study, we test the hypothesis that lymphatic drainage of the brain and cervical lymph nodes play a key role in T-cell mediated immunity of the brain. Experimental allergic encephalomyelitis (EAE) was induced in Lewis rats by the injection of guinea pig spinal cord homogenate in complete Freund's adjuvant into the foot pads. This resulted in paralysis of the hind limbs and infiltration of lymphocytes and microglial activation centred mainly on the spinal cord; little inflammation was seen in the cerebrum. When a brain wound, in the form of cryolesion, was inflicted on one cerebral hemisphere, 8 days after the induction of EAE, there was a 6-fold enhancement of EAE lesions in the brain. This enhancement was reduced by 40% cervical lymphadenectomy at the time of the cryolesion. These results suggest that cervical lymph nodes play a pivotal role in cerebral EAE and may be a major source of brain-directed lymphocytes. If similar mechanisms apply in man, study of cervical lymphocytes and their manipulation could open new therapeutic avenues for the treatment of multiple sclerosis.

Animals↗
PubMed1997

Enhancement of eosinophil survival by lipopolysaccharide through releasing granulocyte-macrophage colony stimulating factor from mononuclear cells from patients with bronchial asthma.

BACKGROUND: The mechanism of bronchoobstruction in asthmatics following inhalation of lipopolysaccharide (LPS) is unclear. OBJECTIVE: In this study we have investigated the effects of the LPS on eosinophil survival rate in stimulating peripheral blood mononuclear cells (PBMCs) from patients with asthma. METHODS: PBMC supernatants from 10 asthmatic patients and 4 healthy subjects were compared for eosinophil survival rate using the same purified eosinophils. Two x 10(6) cells/ml of PBMCs were cultured for 24 hours in RPMI 1640 containing 10% fetal bovine serum along with 10 micrograms/ml of LPS. 10(6) cells/ml of eosinophils were incubated for 96 hours in the presence of PBMC-derived culture supernatants at 75% in volume. RESULTS: The viability of eosinophils incubated with PBMC supernatants from asthmatic patients stimulated with LPS was higher, 62.5% +/- 10.6% (mean +/- SD), than that without LPS, 26.9% +/- 10.8%, and also higher than that of PBMCs from healthy subjects with LPS, 40.0% +/- 15.4%. This increasing activity of asthmatic PBMC stimulated with LPS was markedly inhibited from 72.2% +/- 9.7% to 38.5% +/- 6.8% by addition of mouse anti-human GM-CSF antibody to the PBMC supernatant but not mouse anti-human IL-5 antibody. CONCLUSION: These results suggest that LPS enhances eosinophil survival in asthmatics by increasing the production of GM-CSF from PBMCs.

Adult↗
PubMed1996

Localization of E-cadherin in peripheral glia after nerve injury and repair.

Peripheral nerve injury results in histological and histochemical changes in neurons and glia. We have recently found that Ca(2+)-dependent cell adhesion molecule E-cadherin plays an important role in the selective fasciculation of a particular subset of unmyelinated sensory fibers. In the present immunohistochemical and immunoblot analyses, the temporal profile of the subcellular expression of this molecule in spinal nerves was examined after crushing, transecting, or ligaturing the sciatic nerve in mice with special attention paid to E-cadherin expression in glial cells. After axotomy of the sciatic nerve, distal axons of the proximal stump and the fibers of the distal stump degenerated, but E-cadherin was still detectable at the outer mesaxons of the myelinated axons as long as they remained morphologically intact. Subsequently, Schwann cells proliferated and migrated to form Schwann cell columns (Büngner's bands) as initial responses to denervation, and expressed E-cadherin at their site of contact with each other and later with sprouting axons. At the initial stage of myelin formation, slender processes of a single Schwann cell interdigitated with an enveloped axons, and expressed E-cadherin at the contact site elaborated by a single Schwann cell. Immunoblot analysis on day 7 revealed that E-cadherin was detected in both the proximal nerve segments and the regenerative distal segments, but was negative in the degenerative distal segments. On the basis of present data, it is suggested that E-cadherin might be involved in the stabilization of the peripheral glial network which provides the guidance of sprouting axons and myelination.

Animals↗
PubMed1996

Expression of NF2 gene product merlin in arachnoid villi and meningiomas.

Neurofibromatosis type 2 (NF2) gene encodes a novel 595 amino acid protein named merlin. Recently, Ruttledge et al demonstrated inactivation of NF2 gene in approximately 60% of sporadically occurring meningiomas. Merlin is thought to physiologically exist beneath the cell membrane, and to form a part of modulation in signal transduction, for example, information concerning contact inhibition. In NF2-related tumors, it is supposed that the mutation of merlin results in loss of this signal transduction leading to tumorigenesis. In this paper, we investigated the expression of NF2 gene product merlin in arachnoid villi and meningiomas. The immunohistochemical staining of merlin showed a striking contrast between arachnoid villi and meningiomas. In arachnoid cells, merlin was labeled in the whole cytoplasm, but not within the nuclei. In contrast, in meningiomas, immunoreactivity of merlin was mainly seen in the nuclei. These results suggest that arachnoid cells with normal merlin are capable of normal signal transduction, whereas meningioma cells with mutated merlin show impairment of signal transduction which may lead to tumorigenesis.

Arachnoid↗
PubMed1995

Isolation and characterization of a cDNA encoding a new type of human transcription elongation factor S-II.

We report the isolation of a cDNA encoding a new type of transcription factor S-II, termed h-SII-T1, from a human library. The mRNA corresponding to the clone is highly expressed in testis and ovary. Comparison of the deduced amino acid (aa) sequence with those of other S-II molecules shows that (i) the C-terminal zinc finger (Zf) domain is highly conserved, and (ii) the central segment is most similar to that of the rat testis-specific S-II. Further analyses of the hS-II-T1 aa sequence indicate that its N-terminal sequence exhibits similarity to eubacterial sigma 54. The significance of tissue-specific S-II molecules for the regulation of transcription elongation is discussed.

Amino Acid Sequence↗
PubMed1995

Isolation of a cDNA encoding a mouse TFIID subunit containing histone H4 homology.

A cDNA encoding a mouse transcription factor IID (TFIID) subunit, containing histone H4 homology, was cloned and sequenced. The predicted 678-amino-acid (aa) sequence of this molecule showed 97 and 41% identity to the human and Drosophila melanogaster homologues, respectively. Four putative direct repeats were found in the most highly conserved region in the central part of this protein.

Amino Acid Sequence↗
PubMed1995

Three distinct regions in a rat TFIID subunit containing histone H4 homology.

A cDNA encoding a rat transcription factor IID (TFIID) subunit (p80), with histone H4 homology, was isolated and sequenced. The deduced amino acid (aa) sequence predicts a 678-aa protein with 97% identity to the human and 42% to the Drosophila melanogaster (Dm) homologues. Homologies between three species indicate the presence of three distinct regions.

Amino Acid Sequence↗
PubMed1995

Effects of insulin-like growth factor-I, estrogen, glucocorticoid, and transferrin on the mRNA contents of ovalbumin and conalbumin in primary cultures of quail (Coturnix coturnix japonica) oviduct cells.

The effects of estrogen, dexamethasone, insulin-like growth factor-I (IGF-I), and transferrin on the messenger RNA (mRNA) contents of ovalbumin and conalbumin in primary cultures of quail oviduct cells were investigated. In the absence of one of the above hormones or factors, a decrease in ovalbumin mRNA was prominent. In particular, removal of IGF-I and transferrin caused a significant effect. Studies using a combination of estrogen, dexamethasone, IGF-I and transferrin indicated that IGF-I cooperates with estrogen or dexamethasone and transferrin works with dexamethasone. Specifically, IGF-I enhanced ovalbumin synthesis or increased cellular ovalbumin mRNA content depending on its concentration in the medium in the presence of estrogen. However, the effects of estrogen, dexamethasone, IGF-I, and transferrin were not similarly observed with conalbumin mRNA. These results show that ovalbumin synthesis is controlled by estrogen or glucocorticoid with IGF-I or transferrin and that cellular ovalbumin mRNA content is also regulated by these hormones or transferrin. In contrast, conalbumin synthesis and cellular content of conalbumin mRNA are not affected by these hormones under the conditions of the present study.

Animals↗
PubMed1995

Characterization of perivascular cells in astrocytic tumours and peritumoral oedematous brain.

Perivascular cells (PVCs) form an immunophenotypically defined population that plays an important scavenging role in the perivascular fluid drainage pathways in the rat brain; such cells may also act as antigen-presenting cells. The present study tests the hypotheses that (a) PVCs in human brain are distinct from microglia and haematogenous macrophages, and (b) PVCs within astrocytic tumours and peritumoral oedematous brain tissue react in a similar way to PVCs in the rat brain. Paraffin sections of formalin-fixed tissue from 10 astrocytomas, 10 anaplastic astrocytomas, 10 glioblastoma multiforme, peritumoral oedematous brain and from normal human brain were examined immunocytochemically using antibodies HLA-DR beta-chain for MHC class II antigen, PGM1 and MAC 387 directed against macrophage components, MT1 for T lymphocytes and GFAP for astrocytes. No PVCs, microglia or macrophages were labelled by these techniques in paraffin sections of normal brain. Microglia, macrophages recently derived from haematogenous monocytes and PVCs were labelled by immunocytochemistry in all tumours but were more numerous in glioblastomas than in astrocytomas or anaplastic astrocytomas. Perivascular cells were distinguished by their perivascular position, their expression of MHC class II antigen and were labelled by PGM1 antibody but not by MAC 387 antibody. Microglia and monocyte/macrophages, remote from blood vessels, on the other hand, were strongly labelled by MAC 387, moderately by PGM1 and showed weak expression of MHC class II antigen. A similar pattern of staining was seen in peritumoral oedematous tissue. These findings suggest that PVCs form a defined population of resident cells in the human brain and that they are distinct from microglia, monocytes and macrophages.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Focal brain damage enhances experimental allergic encephalomyelitis in brain and spinal cord.

The immunological basis of multiple sclerosis (MS) is well recognized but the factors inducing MS lesions are unclear. In this study, we test the hypothesis that focal brain injury, inflicted during the pre-clinical stages of experimental allergic encephalomyelitis (EAE), will enhance the severity of immunological damage in the cerebral hemispheres and spinal cord. Acute EAE was induced in 30 Lewis rats by the injection of guinea pig spinal cord homogenate in complete Freund's adjuvant. A cryolesion to the surface of the left cerebral hemisphere was induced at 3 days (n = 6) or 8 days (n = 10) postinoculation (p.i.) and animals were killed at 15 days p.i. Control animals were EAE only (n = 9), cryolesion only (n = 4), EAE and sham cryolesion (n = 5) and normal animals (n = 3). Brain and spinal cord were stained by immunocytochemistry using W3/13 (T-lymphocytes) OX6 (MHC Class II) and GFAP (astrocytes) antibodies. The results showed a 2-fold increase in the number of EAE lesions in the brain with significant and widespread increase of MHC Class II antigen expression by microglia, in the cryolesion EAE 8 days p.i. when compared with EAE only animals. The pattern of enhancement suggests that it is due to (i) local spread of tissue or serum factors from the cryolesion; (ii) neural factors affecting remote regions of the CNS; (iii) stimulation of the immune system which may occur due to products of brain injury draining to regional cervical lymph nodes. Investigation of the mechanisms involved may prove fruitful in establishing factors which initiate, aggravate or ameliorate brain damage in multiple sclerosis.

Animals↗
PubMed1995

Basic fibroblast growth factor may repair experimental cerebral aneurysms in rats.

BACKGROUND AND PURPOSE: To determine whether basic fibroblast growth factor (FGF) can induce proliferative response of endothelial cells and/or smooth muscle cells in aneurysmal lesions, we investigated the effect of the intravenous administration of basic FGF on experimental cerebral aneurysms. METHODS: Cerebral aneurysms were induced in rats by ligation of the unilateral common carotid artery, producing hypertension. Three months later, basic FGF was intravenously injected in two groups of randomly divided rats on days 1, 3, and 5 at two different doses (low dose: 2 micrograms/100 g body wt per day; high dose: 5 micrograms/100 g body wt per day). In a control group, normal saline was similarly injected. The junctions of the anterior cerebral artery (ACA) and the olfactory artery (OA) were examined with a light microscope. Aneurysmal changes were defined as the lesions with discontinuity of the internal elastic lamina in more than half of the outward dilated wall. Depending on whether the smooth muscle cell layer was present in the whole wall, the lesions were divided into two stages: early aneurysmal lesion (whole area) and saccular aneurysm (not totally preserved). RESULTS: The control and the low-dose groups presented no obvious intimal thickening in the intact ACA-OA junctions of both nonligated and ligated sides as well as in the aneurysmal changes. In contrast, in the high-dose group, various degrees of intimal thickening in the wall were detected in 7 of 15 early aneurysmal lesions (P = .019, Fisher's exact test). Immunohistochemistry showed the proliferated cells to be smooth muscle cells. CONCLUSIONS: These results demonstrate that exogenous basic FGF induces the proliferative response of smooth muscle cells in aneurysmal lesions in rats.

Animals↗
PubMed1995

Multicentric infantile myofibromatosis in the cranium: case report.

Infantile myofibromatosis is a rare clinical entity characterized by multiple mesenchymal tumors in the neonatal period. We describe a 15-month-old girl with multicentric cranial lesions involving the parietal and occipital bones associated with a single small subcutaneous lesion in the back. Magnetic resonance imaging clearly demonstrated the isointense lesions on T1-, T2-, and proton density-weighted images, which showed marked gadolinium enhancement of the tumors and adjacent dura mater. A histological examination of the resected temporal lesion revealed the myofibroblastic nature of the tumor cells. This is the first description of magnetic resonance features of multicentric infantile myofibromatosis in the cranium, and gadolinium-enhanced magnetic resonance images were useful in showing dural involvement. The importance of recognizing this disorder is emphasized because of its special clinical behavior.

Contrast Media↗
PubMed1994

Perivascular edema fluid pathway in astrocytic tumors.

Perivascular spaces are anatomical routes for the bulk flow drainage of fluid from the gray matter to the subarachnoid space in normal rat brain. Perivascular cells are the resident scavengers in perivascular spaces. Following focal brain damage, perivascular cells upregulate MHC Class II antigens associated with uptake of edema fluid. Similar cells can be defined in damaged human brain. In the present investigation, the distribution of MHC Class II upregulated perivascular cells was measured in 30 astrocytic tumors and adjacent edematous tissues by immunocytochemistry using the following antibodies: HLA-DR (MHC Class II), PGM1 and MAC387 (macrophages). Perivascular cells were PGM1+/MAC387- and were located in perivascular spaces along blood vessels of all sizes. MHC Class II+ perivascular cells were distributed mainly in the tumors but in some cases (4 of 10 in astrocytomas, 4 of 10 in anaplastic astrocytomas, and 7 of 10 in glioblastomas) they were also found in adjacent edematous brain. The extensive MHC Class II expression on perivascular cells suggests that perivascular cells play a scavenging role in the perivascular spaces in human brain. The results of the present study indicate the similarity between perivascular spaces in human and rat brains and emphasize the significance of perivascular spaces as anatomical routes for edema fluid drainage from human brain tissue.

Animals↗
PubMed1994

Insulin-like growth factor-I messenger RNA content in the oviduct of Japanese quail (Coturnix coturnix japonica): changes during growth and development or after estrogen administration.

Complementary DNA (cDNA) of insulin-like growth factor-I (IGF-I) of Japanese quail was cloned. The nucleotide sequence analysis of the cDNA showed that only seven bases differed from those of chicken IGF-I cDNA in the 440 bases of the cloned region. This difference in nucleotide sequence did not cause changes in the amino acid sequence. Using this cloned cDNA, the changes in IGF-I mRNA content in the tissues of female quail during growth and development were investigated. In the oviduct, IGF-I mRNA was high about 5 weeks after hatching, concomitant with the rapid increase in total DNA content in this tissue (and the increases in total RNA content and RNA/DNA ratio). It decreased after 6 weeks, in accordance with the appearance of ovalbumin mRNA. When immature quails (6-day-old) were injected with diethylstilbestrol (DES), induction of IGF-I mRNA was observed after 24 hr. A few days later, there was a strong induction of ovalbumin mRNA. These two inductions were dependent on the dose of DES. The sequential inductions of these two mRNAs were also noted when DES was re-administered to the immature quail to which it had been first administered and from which then withdrawn. The present results showed that IGF-I gene is expressed extensively during development of the oviduct, probably in accordance with the activity of DNA replication, because the highest IGF-I mRNA content was observed when the total DNA content of the tissues increased extensively. The results suggest that IGF-I in the oviduct of Japanese quail works in an autocrinal or paracrinal mode during the development of this tissue.

Amino Acid Sequence↗
PubMed1994

Synthesis of multilamellar phospholipids in meningioma cells.

This report is to demonstrate that specimen pretreated with tannic acid before osmification permits the ultrastructural identification of multilamellar phospholipids in 23 of the 30 meningiomas. The phospholipids very often had a fingerprint-like appearance, and were found within the cytoplasm of meningioma cells, among the plasma membranes and in the extracellular matrices. A preferential ultrastructural localization of multilamellar phospholipids to the glycogen-rich area within the cytoplasm was seen in 5 cases. They were intermingled with glycogen granules, or the latter were precipitated on the phospholipids. It is suggested that glycogen may serve as a source of energy for precursors of phospholipid synthesis in meningioma cells.

Adult↗