Structure and function of vascular endothelial growth factor receptor-1 and -2.
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Capillary Permeability↗
Biomedical subjects
M Shibuya
Publications and source records attributed to M Shibuya.
Involvement of VEGF and its receptors in ascites tumor formation.
Vascular endothelial growth factor (VEGF) has potent endothelial cell mitotic and vascular permeability activity. Several reports have suggested that VEGF may be one of the major factors regulating ascites formation, although no quantitative and systematic analyses have been carried out. To determine the role of VEGF in ascites formation, we examined the expression of VEGF in 13 mouse ascites tumors (5 sarcomas, 3 carcinomas, and 5 hematopoietic malignancies). We found that significant amounts (6-850 ng/mL) of biologically active VEGF accumulated in the ascites fluid of all 13 tumors, particularly in tumors of sarcoma and carcinoma origin (430 +/- 234 ng/mL). The microvessel densities in the peritoneal walls of tumor-bearing mice, which are significantly higher than those in healthy mice, basically correlated with but did not parallel VEGF concentrations, suggesting the existence of an additional modulator(s) of the angiogenic process. Administration of anti-mouse VEGF-neutralizing antibody to mice bearing the carcinoma-derived ascites tumor MM2 suppressed ascites accumulation, tumor growth, and tendency to bleed. These results directly demonstrate the crucial role of VEGF in carcinoma-derived ascites tumor formation in vivo.
Animals↗
Intra-arterial infusion of fasudil hydrochloride for treating vasospasm following subarachnoid haemorrhage.
In this pilot study we treated cerebral vasospasm in patients with subarachnoid haemorrhage to assess intra-arterial fasudil hydrochloride. We analysed effects of intra-arterial infusion on angiographically evident cerebral vasospasm in 10 patients including 3 with symptoms of vasospasm. Over 10 to 30 min 15 to 60 mg was administered via the proximal internal carotid artery or vertebral artery following standard angiography, without superselective techniques. A total of 24 arterial territories (21 internal carotid, 3 vertebral) were treated. Angiographic improvement of vasospasm was demonstrated in 16 arterial territories (local dilation in 2, diffuse dilation in 14) in 9 patients. In 2 symptomatic patients, intra-arterial fasudil hydrochloride was associated with resolution of symptoms without sequelae. In the third symptomatic patient the benefit of fasudil hydrochloride was only temporary, and a large cerebral infarction occurred. All asymptomatic patients showed no progression of angiographic to symptomatic vasospasm after treatment with intra-arterial fasudil hydrochloride. No adverse effect was encountered.
1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
Decreased expression of receptors for vascular endothelial growth factor and sinusoidal endothelial cell damage in cold-preserved rat livers.
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Animals↗
Expression of vascular endothelial growth factor (VEGF) in human thyroid neoplasms.
Vascular endothelial growth factor (VEGF), also known as vascular permeability factor (VPF), is an angiogenic factor that plays important roles in tumor growth. Angiogenesis studies on VEGF deal with various types of malignant tumors, but very little is known about the role or significance of VEGF in human thyroid neoplasms. Therefore, in the current study, we determined whether VEGF is found in normal and neoplastic thyroids and whether its expression is altered in different histological types of thyroid neoplasms. Reverse-transcription polymerase chain reaction (RT-PCR) analysis showed that all specimens of thyroid tumors expressed bands corresponding to 121-, 165-, and 189-amino acid forms of VEGF. Northern blot analysis showed an increase in VEGF mRNA levels in neoplastic tissues in comparison with normal thyroid samples. By nonisotopic in situ hybridization, most of the tumor cells in follicular adenomas expressed VEGF mRNA, whereas VEGF mRNA expression was identified only in epithelium of isolated follicles in normal thyroid tissues. In papillary thyroid carcinomas, an intense labeling with VEGF probe was often found in overlying tumor cells of neoplastic papillae. VEGF expression was distinctly intensified in undifferentiated carcinoma cells that were immediately adjacent to necrotic foci. The immunohistochemical localizations of VEGF protein were comparable to the localization of VEGF mRNA. In conclusion, our results suggest that the histological types of thyroid tumor may determine the vascular pattern through a paracrine mechanism involving VEGF.
Blotting, Northern↗
Alteration of the PTEN/MMAC1 gene locus in primary lung cancer with distant metastasis.
The PTEN/MMAC1 gene located at 10q23, has been proposed to be a tumor suppressor gene. To determine the involvement of alteration of the PTEN/MMAC1 gene in carcinogenesis and the progression of primary lung cancers, we analyzed tumor samples of primary and distant metastatic sites and normal lung tissue samples of 30 patients with advanced lung cancer with distant metastasis. The tissues were analyzed for allelic deletion and mutational inactivation of PTEN/MMAC1 by loss of heterozygosity (LOH) analysis, polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP), and direct sequence analysis. LOH of the PTEN/MMAC1 locus was common in each histologic type of primary lung cancer. In this study, the overall allelic deletion rate was 33.3% (7/21). Allelic loss at the primary site and that at the metastatic site of each patient, were identical; in most cases, it seemed that the allelic loss had occurred before metastasis. Sequence analysis of the PTEN/MMAC1 gene revealed a G to C substitution located 8 bp upstream of the coding region of exon 1 and which seems to be a polymorphism, in 4 of the 30 cases. Somatic mutations of the PTEN/MMAC1 gene were not identified in any of the tumors at the primary and metastatic sites. These data indicate that point mutations in the PTEN/MMAC1 gene are probably not an important factor in tumorigenesis and the progression of a major subset of lung cancers. Due to frequent allelic loss at the PTEN/MMAC1 locus occurring at a stage earlier than the metastatic process, alternative mechanisms in which the remaining allele is inactivated such as methylation or homozygous deletion of a small region of the gene that can not be detected by the usual analysis, or alteration of other important tumor suppressor genes lying close to the PTEN/MMAC1 gene on 10q23, may be involved in the tumorigenesis of lung cancers of all histologic subtypes.
Alleles↗
Vascular endothelial growth factor overproduced by tumour cells acts predominantly as a potent angiogenic factor contributing to malignant progression.
To elucidate the role of vascular endothelial growth factor (VEGF), an endothelial cell-specific mitogen, in tumour angiogenesis and malignant progression, an expression vector harboring human VEGF cDNA was stably transfected into three human cancer cell lines with poor VEGF productivity. Though their in vitro growth rate and intrinsic productivity of another angiogenic factor, basic fibroblast growth factor (bFGF), were not changed by transfection, those clones with higher VEGF production were endowed with tumorigenic and angiogenic potentials as follows: firstly, nontumorigenic, lung carcinoma QG90 cells having lower bFGF productivity acquired tumorigenicity as well as significant in vivo angiogenesis-inducing ability, secondly, tumorigenic colorectal carcinoma RPMI4788 cells having higher potency for bFGF production could form more vascularized solid tumour with faster growth rate and thirdly, oestrogen-dependent breast carcinoma MCF-7 cells, which did not produce detectable bFGF, acquired tumorigenicity even in the absence of oestrogen and the solid tumour growth rate was remarkably enhanced, accompanied with increased vascularization, in the presence of oestrogen. These results suggest that tumour progression closely depends on angiogenesis, and VEGF significantly contributes to malignant progression of a variety of tumour cells through its potent angiogenic activity, independent on the bFGF productivity of tumour cells.
Animals↗
p-Coumaroyltriacetic acid synthase, a new homologue of chalcone synthase, from Hydrangea macrophylla var. thunbergii.
Chalcone synthase and stilbene synthase are plant-specific polyketide synthases. They catalyze three common consecutive decarboxylative condensations and specific cyclization reactions. They are highly homologous to each other, and are likely to fall into a family of polyketide synthases along with acridone synthase and bibenzyl synthase. Two cDNA clones (named HmC and HmS), both of which show high homology to the known chalcone synthases, were obtained from leaves of Hydrangea macrophylla var. thunbergii. They were expressed in Escherichia coli in order to determine their enzyme functions. Detection of chalcone formation clearly indicated that HmC encoded chalcone synthase, while HmS protein catalyzed the formation of neither chalcone nor stilbene. However, a novel pyrone, a lactonization product of a linear tetraketide was detected in reaction products of HmS protein. This proves that HmS encodes a novel polyketide synthase that catalyzes only chain elongation without cyclization.
Acyltransferases↗
Two branches of the lupeol synthase gene in the molecular evolution of plant oxidosqualene cyclases.
Two new triterpene synthase cDNAs, named as OEW and TRW, were cloned from olive leaves (Olea europaea) and from dandelion roots (Taraxacum officinale), respectively, by the PCR method with primers designed from the conserved sequences found in the known oxidosqualene cyclases. Their ORFs consisted of 2274 bp nucleotides and coded for 758 amino acid long polypeptides. They shared high sequence identity (78%) to each other, while they showed only about 60% identities to the known triterpene synthases LUPI (lupeol synthase clone from Arabidopsis thaliana) and PNY (beta-amyrin synthase clone from Panax ginseng) at amino acid level. To determine the enzyme functions of the translates, they were expressed in an ERG7 deficient yeast mutant. Accumulation of lupeol in the cells of yeast transformants proved both of these clones code for lupeol synthase proteins. An EST (expression sequence tag) clone isolated from Medicago truncatula roots as a homologue of cycloartenol synthase gene, exhibits high sequence identity (75-77%) to these two lupeol synthase cDNAs, suggesting it to be another lupeol synthase clone. Comparatively low identity (approximately 57%) of LUP1 from Arabidopsis thaliana to either one of these clones leaves LUP1 as a distinct clone among lupeol synthases. From these sequence comparisons, now we propose that two branches of lupeol synthase gene have been generated in higher plants during the course of evolution.
Cloning, Molecular↗
Type VI collagen immunoreactivity in skeinoid fibers in small intestinal stromal tumors.
By immunoperoxidase analysis for types I to VI collagen, elastin, cytoskeletal components and some glycoproteins, we found type VI collagen immunoreactivity in amorphous eosinophilic deposits (skeinoid fibers) in three small intestinal stromal tumors. Negative results were obtained for types I, II, III, IV and V collagen, elastin, laminin, ubiquitin, intracellular filaments such as actin, desmin, vimentin, calponin and caldesmon, and glycoprotein such as lysozyme, factor XIIIa, beta2-microglobulin, alpha1-antitrypsin and alpha1-antichymotrypsin. In two lesions, the periodic acid-Schiff-positive skeinoid fibers were also focally labeled for amyloid P component.
Adult↗
Effect of diabetes on vitamin B6 requirement in experimental animals.
AIM: In the diabetic state, energy must be supplied mainly by amino acids and fat; therefore the metabolic processes are very similar to those of animals fed a high-protein diet. Vitamin B6-dependent enzymes, which are highly involved in amino acid metabolism, are important in diabetics. We investigated vitamin B6 content, and aspartate aminotransferase and glycogen phosphorylase activities, in several tissues of streptozotocin-induced diabetic and control rats. METHODS: The rats were fed a vitamin B6-free diet and administered an equivalent amount of pyridoxine based on body weight. RESULTS: Vitamin B6 content in all tissues examined, except for the liver, was lower in the diabetics than in controls. Aspartate aminotransferase activity was higher in the liver of diabetics than in the controls, but not in the other tissues. Glycogen phosphorylase activity in the gastrocnemius muscle of diabetics decreased to two-thirds of the control level. CONCLUSIONS: These data might indicate that diabetic animals should have a higher intake of vitamin B6 because a diabetic state can lead to a vitamin B6-deficiency.
Animals↗
Fasudil, a protein kinase inhibitor, prevents the development of endothelial injury and neutrophil infiltration in a two-haemorrhage canine subarachnoid model.
We examined the possible prophylactic potential of fasudil, a protein kinase inhibitor, on the development of endothelial injury and neutrophil infiltration after subarachnoid haemorrhage (SAH). Using the two haemorrhage canine model, fasudil (3 mg/kg) was infused intravenously for 30 min twice daily (days 1-7) and related histological changes were observed by light and electron microscopy. On day 7 characteristic features of the basilar arteries included corrugation of the elastic lamina and endothelial disruption; fasudil inhibited this endothelial damage. Marked neutrophil infiltration into the subarachnoid space was not detected until day 3. On day 7 a large number of neutrophils was observed in the subarachnoid space around all the basilar arteries examined; fasudil treatment significantly inhibited neutrophil infiltration. Our findings suggest that: (1) endothelial injury and neutrophils play a major role in the pathogenesis of cerebral vasospasm; and (2) fasudil inhibited both endothelial damage and neutrophil infiltration, and therefore protein kinase pathways may have a role in these pathological events. Copyright 1999 Harcourt Publishers Ltd.
Journal Article↗
Vascular endothelial growth factor-C gene expression in papillary and follicular thyroid carcinomas.
BACKGROUND: Vascular endothelial growth factor-C (VEGF-C) is known to be related to development of lymphatic vessels. Papillary thyroid carcinoma characteristically metastasizes to regional lymph nodes, whereas follicular thyroid carcinoma commonly spreads hematogenously. The present study was designed to determine whether expression of the VEGF-C gene is related to the different metastatic features of these 2 types of thyroid carcinoma. METHODS: Thyroid carcinoma specimens were obtained from 15 patients with papillary carcinoma and 4 patients with follicular carcinoma of the thyroid. VEGF-C gene expression was examined by Northern blotting and in situ hybridization. Immunohistochemistry was performed to localize the deposition of VEGF-C protein. RESULTS: The ratios of VEGF-C gene expression determined by Northern blot analysis were significantly higher in papillary than in follicular carcinoma. Nonmalignant thyroid tissue from patients with papillary carcinoma also expressed higher levels of VEGF-C than tissue from patients with follicular carcinoma. Expression of the VEGF-C gene was observed by in situ hybridization in cells of papillary thyroid carcinoma but not in those of follicular carcinoma. Positive staining with antibody against VEGF-C was detected in papillary cancer cells. CONCLUSIONS: Concurrent overexpression of the VEGF-C gene by both tumor cells and the surrounding tissue may be related to the prevalence of intrathyroidal spread through lymphatics and regional lymph node metastasis in patients with papillary thyroid carcinoma.
Adenocarcinoma, Follicular↗
Inhibition of neutrophil migration by a protein kinase inhibitor for the treatment of ischemic brain infarction.
This study investigated the therapeutic potential of agents that inhibited neutrophil infiltration in cerebral ischemic infarction. The migration of neutrophils elicited by N-formyl-methionyl-leucyl-phenylalanine, tumor necrosis factor, C5a or platelet-activating factor was potently inhibited by fasudil, an inhibitor of protein kinases including rho kinase, protein kinase C and myosin light chain kinase, and hydroxy fasudil, a metabolite of fasudil, in vitro. In a microembolism model in rats, myeloperoxidase-quantified neutrophil accumulation in the ischemic brain was observed 24 hr after embolization. Intravenous administration of fasudil prevented the accumulation of neutrophils. In rats given fasudil, myeloperoxidase activity in the ipsilateral hemisphere (0.04+/-0.01 unit/g wet tissue) was significantly lower than that in ischemic rats (0.11+/-0.02 unit/g wet tissue). Fasudil also significantly reduced the size of the infarct area and improved neurological functions. These results suggest that neutrophil infiltration into the ischemic brain is involved in the pathogenesis of ischemic injury and that inhibiting neutrophil infiltration may provide an effective therapeutic intervention to reduce ischemic injury.
1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
Establishment of specific pathogen-free rabbit colonies with limited-flora rabbits associated with conventional rabbit flora, and monitoring of their cecal flora.
In the present study we attempted to establish specific-pathogen-free (SPF) rabbit breeding colonies with two groups of limited-flora (LF) rabbits, both ex-germfree rabbits, and their offspring. Two groups of LF rabbits associated with cecal flora of conventional (CV) rabbits produced in a previous study [Exp. Animals, submitted], were transferred to individual barrier rooms and some of the LF rabbits were accommodated in isolators to maintain the basic flora for SPF rabbits. The composition of the cecal flora of LF rabbits was stable for a long period; bacteroides remained predominant and clostridia dominant. From the SPF rabbits, different types of bacteria, e.g., enterobacteriaceae and streptococci, which could not be isolated in the isolator were detected at a low population level at an early stage in the establishment of the SPF colonies, but the basic composition of the cecal flora was mainly bacteroidaceae and clostridia and did not change over a long period, and the floral composition became similar to that of CV rabbits. The fertility and weaning rates of the SPF rabbits were satisfactory for a SPF rabbit colony. In addition, these SPF colonies were free of more than one year rabbit-specific pathogens.
Animals↗
Production of ex-germfree rabbits for establishment of specific pathogen-free (SPF) colonies.
Nine groups of ex-germfree (GF) rabbits were produced by inoculation of hysterectomy-derived GF rabbits with various combinations of cecal bacteria isolated from conventional (CV) rabbits in order to establish a barrier-sustained colony. Six strains of Bacteroides and two strains of Streptococcus isolated from CV rabbits (2 to 3 weeks old) were used for pretreatment. The mortality of ex-GF rabbits inoculated with the anaerobic growth (CF) on EG or SM10 plates inoculated with a 10(-5) dilution of cecal contents was 71.4 to 94.4% when given without pretreatment. All ex-GF rabbits pretreated with Bacteroides alone survived, but the mortality of ex-GF rabbits inoculated with Bacteroides plus Streptococcus strains as pretreatment was 20 and 45.4%. The mortality of ex-GF rabbits inoculated with only Bacteroides was 43%. All ex-GF rabbits inoculated with Bacteroides plus anaerobic growth (CF), cecal suspension of ex-GF mice which had been inoculated with cecal suspensions of CV rabbits (MF) or chloroform-treated cecal suspension (CHF) survived, but CHF inoculated ex-GF rabbits were in an unhealthy condition with slight diarrhoea. These data indicate that inoculation with Bacteroides strains as pretreatment plus CF or MF was required to convert GF rabbits to the normal state.
Animals↗
[Open surgery for pontine hemorrhage: experience in 3 cases].
Experience in three pontine hemorrhage cases which were treated by open surgery is recorded here. They were operated on by trans-fourth ventricular, subtemporal transtentorial on retromastoid suboccipital approaches. The neurological symptom improved noticeably in one case who was operated on through the retromastoid suboccipital approach seven days after the onset. The pontine hemorrhage can even be cured with open surgery which is performed in the early stage and through the operative approach.
Aged↗
[The relationship between coagulation time and bilateral occurrence in chronic subdural hematoma].
The relationship between the bilateral occurrence and coagulation time was analyzed in 137 cases of chronic subdural hematoma. Bilateral chronic subdural hematomas more frequently happened in the patient with coagulation time elongation beyond the normal control. This tendency was significant in the non-traumatic group and bilateral subdural hematomas were found in: 45% in prothrombin time (PT)-elongated group vs 10.3% in non-elongated group and 38.9% in activated partial thromboplastin time (aPTT)-elongated group vs 14.6% in non-elongated group. The ratio of PT and aPTT coagulation time against the normal control was significantly larger in the bilateral group than in the unilateral group. The ratio was as follows: PT ratio was 1.056 in bilateral group and 0.995 in unilateral group. aPTT ratio was 1.051 in bilateral group and 0.954 in unilateral group. Furthermore the bilateral hematomas tended to happen in hemodialysis cases, and in patients on warfarin or anti-platelet drugs. Bilateral hematomas were found in 41.7%, 37.5% and 33.3% respectively. The ratio of PT and aPTT coagulation time was as follows: PT ratio was 1.040 in hemodialysis cases and 1.082 in warfarin-applicated cases. aPTT ratio was 1.022 in hemodialysis cases and 1.055 in warfarin-applicated cases. These results suggest that the suppressed coagulation ability and platelet function are involved in the genesis of bilateral chronic subdural hematomas.
Aged↗