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Biomedical subjects

C Suri

Publications and source records attributed to C Suri.

At least 19 recordsLinked to original sources
PubMed2006

The emergency of molecular and transgenic lymphology: what do we (really) know so far?

Since its first sequential visualization in 1902 by Florence Sabin, the development and maintenance of the lymphatic system has intrigued scientists and clinicians worldwide. Its close ties to the vascular network, relevance in the spread and control of parasitic and cancerous diseases, and involvement in the development of other disease states manifested by lymphedema are well known. What is still not clear is how the system develops in the first place, and this limits its effective manipulation for the management of disease states. The aim of the current article is to summarize advances that have been made via genetic approaches using transgenic and knockout mice. It should be noted that studies of lymphatic vessel growth utilizing protein reagents or transgenic technology alone, in a tissue/cell culture environment, during tumor metastasis, in a lymphatic disease paradigm, or during tissue repair, have shown that various growth factors, such as platelet-derived growth factor BB (1), hepatocyte growth factor (2), fibroblast growth factor (3), and VEGF-A (4) appear to play a role. This article is a commentary on the usefulness of specific genetic engineering tools in understanding the development of the lymphatic system--with a focus on the questions that have been addressed using these tools, the extent to which the questions have actually been answered, and the questions that have subsequently been raised. It is not meant to be a discussion of protein reagents or of specific biological situations that exhibit lymphangiogenesis (see reviews 5-7).

Angiopoietins↗
PubMed2002

Chaotic mixing generated by acoustic streaming.

The acoustic mixer presented in this paper is a closed cylinder containing chemical solutions. The ultrasound was generated in a water bath outside of the cylinder. The mixing efficiency was measured by using a laser-photodiode system and by mixing iodine and sodium thiosulfate. Iodine solution has a light brown color which becomes transparent if the solution is mixed with sodium thiosulfate. The unmixed regions of the solution in the container remain dark. Starch was used to make the solution darker. Considering the relative position between the cylinder and the transducer, it was shown that displacements parallel to the axes of the streaming have little effect on the mixing speed. Indeed, the distance of the cylinder from the center of the streaming is more important to obtain ideal mixing performances. The frequency and size of the transducers has been investigated too and little effect was found. In contrast, the wave amplitude seems to be the biggest factor in obtaining rapid mixing.

Journal Article↗
PubMed2002

BDNF overexpression increases dendrite complexity in hippocampal dentate gyrus.

There is increasing evidence that brain-derived neurotrophic factor (BDNF) modulates synaptic and morphological plasticity in the developing and mature nervous system. Plasticity may be modulated partially by BDNF's effects on dendritic structure. Utilizing transgenic mice where BDNF overexpression was controlled by the beta-actin promoter, we evaluated the effects of long-term overexpression of BDNF on the dendritic structure of granule cells in the hippocampal dentate gyrus. BDNF transgenic mice provided the opportunity to investigate the effects of modestly increased BDNF levels on dendrite structure in the complex in vivo environment. While the elevated BDNF levels were insufficient to change levels of TrkB receptor isoforms or downstream TrkB signaling, they did increase dendrite complexity of dentate granule cells. These cells showed an increased number of first order dendrites, of total dendritic length and of total number of branch points. These results suggest that dendrite structure of granule cells is tightly regulated and is sensitive to modest increases in levels of BDNF. This is the first study to evaluate the effects of BDNF overexpression on dendrite morphology in the intact hippocampus and extends previous in vitro observations that BDNF influences synaptic plasticity by increasing complexity of dendritic arbors.

Animals↗
PubMed2001

Absence of hippocampal mossy fiber sprouting in transgenic mice overexpressing brain-derived neurotrophic factor.

Excess neuronal activity upregulates the expression of two neurotrophins, nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) in adult hippocampus. Nerve growth factor has been shown to contribute the induction of aberrant hippocampal mossy fiber sprouting in the inner molecular layer of the dentate gyrus, however the role of prolonged brain-derived neurotrophic factor exposure is uncertain. We examined the distribution and plasticity of mossy fibers in transgenic mice with developmental overexpression of brain-derived neurotrophic factor. Despite 2--3-fold elevated BDNF levels in the hippocampus sufficient to increase the intensity of neuropeptide Y immunoreactivity in interneurons, no visible changes in mossy fiber Timm staining patterns were observed in the inner molecular layer of adult mutant hippocampus compared to wild-type mice. In addition, no changes of the mRNA expression of two growth-associated proteins, GAP-43 and SCG-10 were found. These data suggest that early and persistent elevations of brain-derived neurotrophic factor in granule cells are not sufficient to elicit this pattern of axonal plasticity in the hippocampus.

Animals↗
PubMed2000

Angiopoietin 2 expression in the retina: upregulation during physiologic and pathologic neovascularization.

Vascular development in the embryo requires coordinated signaling through several endothelial cell-specific receptors; however, it is not known whether this is also required later during retinal vascular development or as part of retinal neovascularization in adults. The Tie2 receptor has been implicated in stabilization and maturation of vessels through action of an agonist ligand, angiopoietin 1 (Ang1) and an antagonistic ligand, Ang2. In this study, we have demonstrated that ang2 mRNA levels are increased in the retina during development of the deep retinal capillaries by angiogenesis and during pathologic angiogenesis in a model of ischemic retinopathy. Mice with hemizygous disruption of the ang2 gene by insertion of a promoterless beta-galactosidase (beta gal) gene behind the ang2 promoter, show constitutive beta gal staining primarily in cells along the outer border of the inner nuclear layer identified as horizontal cells by colocalization of calbindin. During development of the deep capillary bed or retinal neovascularization, other cells in the inner nuclear layer and ganglion cell layer, in regions of neovascularization, stain for beta gal. Thus, there is temporal and spatial correlation of Ang2 expression with developmental and pathologic angiogenesis in the retina, suggesting that it may play a role.

Angiopoietin-1↗
PubMed2000

[Clinical experience with the use of benzylalcohol and amyl-m-cresol (Strepsils) in stomatological diseases].

The results gained with the treatment of benzylalcohol and amyl-m-cresol tablets in oral inflammatic diseases (153 cases) and in the prophylaxis of possible infections (119 cases) accompanied with surgical interventions has been summarised. It was concluded that, the average healing process shortened by 30% in time, and the quality parameters (pain, function etc.) showed 30% better results in 78.4% of the cases treated with Strepsils. 88.3/ of patients preferred to get the tablets, the tolerability was excellent. The two third of the patients suffering from inflammatory diseases reported reduction of the pain within the first 60 minutes after the very first tablet application. The experience gained with 272 patients showed very good effectivity especially in the cases aphtha, gingivostomatitis herpetica, stomatitis mycotica, gingivitis, denture stomatitis, erythema exsudativum multiforme, stomatopharyngitis, periodontitis. The drug has showed of remarkable result in the prophylaxis of periodontal, dentoalveolar, implant, soft tissue, maxillofacial surgical interventions.

Adolescent↗
PubMed2000

[Large cysts of dental origin in the maxilla].

The authors give a common survey of clinical and pathological appearance of cysts of maxillary sinuses, especially their dental origin. They review the possibilities of diagnosis and show the treatment technic they used the past 4 years on 11 cases. They emphasise the importance of radiological controlling the root canal treated teeth and the role of the dentist in instructing the patient about this.

Adult↗
PubMed1999

Leakage-resistant blood vessels in mice transgenically overexpressing angiopoietin-1.

Angiopoietin-1 (Ang1) and vascular endothelial growth factor (VEGF) are endothelial cell-specific growth factors. Direct comparison of transgenic mice overexpressing these factors in the skin revealed that the VEGF-induced blood vessels were leaky, whereas those induced by Ang1 were nonleaky. Moreover, vessels in Ang1-overexpressing mice were resistant to leaks caused by inflammatory agents. Coexpression of Ang1 and VEGF had an additive effect on angiogenesis but resulted in leakage-resistant vessels typical of Ang1. Ang1 therefore may be useful for reducing microvascular leakage in diseases in which the leakage results from chronic inflammation or elevated VEGF and, in combination with VEGF, for promoting growth of nonleaky vessels.

Angiopoietin-1↗
PubMed1999

Brain-derived neurotrophic factor transgenic mice exhibit passive avoidance deficits, increased seizure severity and in vitro hyperexcitability in the hippocampus and entorhinal cortex.

Transgenic mice overexpressing brain-derived neurotrophic factor from the beta-actin promoter were tested for behavioral, gross anatomical and physiological abnormalities. Brain-derived neurotrophic factor messenger RNA overexpression was widespread throughout brain. Overexpression declined with age, such that levels of overexpression decreased sharply by nine months. Brain-derived neurotrophic factor transgenic mice had no gross deformities or behavioral abnormalities. However, they showed a significant passive avoidance deficit. This deficit was dependent on continued overexpression, and resolved with age as brain-derived neurotrophic factor transcripts decreased. In addition, the brain-derived neurotrophic factor transgenic mice showed increased seizure severity in response to kainic acid. Hippocampal slices from brain-derived neurotrophic factor transgenic mice showed hyperexcitability in area CA3 and entorhinal cortex, but not in dentate gyrus. Finally, area CA1 long-term potentiation was disrupted, indicating abnormal plasticity. Our data suggest that overexpression of brain-derived neurotrophic factor in the brain can interfere with normal brain function by causing learning impairments and increased excitability. The results also support the hypothesis that excess brain-derived neurotrophic factor could be pro-convulsant in the limbic system.

Age Factors↗
PubMed1999

Expression of angiopoietin-1, angiopoietin-2, and the Tie-2 receptor tyrosine kinase during mouse kidney maturation.

The Tie-2 receptor tyrosine kinase transduces embryonic endothelial differentiation, with Angiopoietin-1 (Ang-1) acting as a stimulatory ligand and Ang-2 postulated to be a naturally occurring inhibitor. Expression of these genes was sought during mouse kidney maturation from the onset of glomerulogenesis (embryonic day 14 [E14]) to the end of nephron formation (2 wk postnatal [P2]), and during medullary maturation into adulthood (P8). Using Northern and slot blotting of RNA extracted from whole organs, these three genes were expressed throughout the experimental period with peak levels at P2 to P3. By in situ hybridization analysis at E18, P1, and P3, Ang-1 mRNA was found to localize to condensing renal mesenchymal cells, proximal tubules, and glomeruli in addition to maturing tubules of the outer medulla. In contrast, Ang-2 transcripts were more spatially restricted, being detected only in differentiating outer medullary tubules and the vasa recta bundle area. Using in situ hybridization and immunohistochemistry, Tie-2 was detected in capillaries of the nephrogenic cortex, glomerular tufts, cortical interstitium, and medulla including vessels in the vasa recta. Using Western blotting of protein extracted from whole organs, Tie-2 protein was detected between E14 and P8 with tyrosine phosphorylated Tie-2 evident from E18. These data are consistent with the hypothesis that Tie-2 has roles in maturation of both glomeruli and vasa rectae.

Aging↗
PubMed1999

[Risk patients in dentistry].

Authors study the risk diseases in dental practice. They analyze the possible complications and the methods of their prevention in each risk group. They take deal with the importance of antibiotic prophylaxis, the problems of local anaesthesia and the management of patients who suffer from coagulation disturbances. They present the management of risk patients in two cases. They emphasize the importance of anamnestic history in every case before dental treatment.

Acenocoumarol↗
PubMed1999

[Experience with clindamycin in stomatologic diseases].

In 114 patients suffering from dental inflammatory diseases (periostitis, gingivitis, sinusitis, periodontitis etc.) and in 41 cases of dental surgical procedures (implantation, dentoalveolar surgery etc.) 3 x 300 mg/day clindamycin was applied during 7 days in the framework of GCP phases IV. In 150 cases (97%) the product proved to be effective and only in 2 cases a mild side effect was observed. On the base of the results clindamycin can be advised for the treatment of stomatological diseases.

Aminoglycosides↗
PubMed1998

Increased vascularization in mice overexpressing angiopoietin-1.

The angiopoietins and members of the vascular endothelial growth factor (VEGF) family are the only growth factors thought to be largely specific for vascular endothelial cells. Targeted gene inactivation studies in mice have shown that VEGF is necessary for the early stages of vascular development and that angiopoietin-1 is required for the later stages of vascular remodeling. Here it is shown that transgenic overexpression of angiopoietin-1 in the skin of mice produces larger, more numerous, and more highly branched vessels. These results raise the possibility that angiopoietins can be used, alone or in combination with VEGF, to promote therapeutic angiogenesis.

Angiopoietin-1↗
PubMed1998

[The use of benzyl alcohol and amyl-m-cresol (Strepsils) in the oral cavity. (Review of the literature and first clinical experiences)].

The authors summarised the literature data of benzylalcohol and amyl-m-cresol. In the clinical practice they used Strepsils in the treatment of 22 patients suffered from oral inflammatic diseases and in the 20 prophylactic cases of oral surgical interventions. The preliminary clinical report shows that, the Strepsils seems to be very effective in the treatment of oral inflammations and in the prophylaxis too.

Adolescent↗
PubMed1997

Angiopoietin-2, a natural antagonist for Tie2 that disrupts in vivo angiogenesis.

Angiogenesis is thought to depend on a precise balance of positive and negative regulation. Angiopoietin-1 (Ang1) is an angiogenic factor that signals through the endothelial cell-specific Tie2 receptor tyrosine kinase. Like vascular endothelial growth factor, Ang1 is essential for normal vascular development in the mouse. An Ang1 relative, termed angiopoietin-2 (Ang2), was identified by homology screening and shown to be a naturally occurring antagonist for Ang1 and Tie2. Transgenic overexpression of Ang2 disrupts blood vessel formation in the mouse embryo. In adult mice and humans, Ang2 is expressed only at sites of vascular remodeling. Natural antagonists for vertebrate receptor tyrosine kinases are atypical; thus, the discovery of a negative regulator acting on Tie2 emphasizes the need for exquisite regulation of this angiogenic receptor system.

Amino Acid Sequence↗
PubMed1995

[Management of patients with maxillofacial injuries at the Oral Surgery Department of the Hungarian Central Military Hospital (analysis of a 10-year patient material)].

The authors have worked up the most important data of as many as 500 patients with malar and mandibular bone injuries. It is established that these injuries mostly derive from aggressive actions and traffic accidents. During this decade the ratio of injuries regarding the mandible and centre of the face has changed from 2.5:1 to 1:1. Since January 1, 1994 the number of managed injured patients has significantly increased, as a consequence of the maxillofacial service connected into the duty management in Budapest.

Accidents, Traffic↗
PubMed1994

Molecular phenotype of simian virus 40 large T antigen-induced primitive neuroectodermal tumors in four different lines of transgenic mice.

BACKGROUND: We compared the molecular phenotypes of central nervous system tumors arising in four different lines of transgenic mice (TGM) carrying the Simian virus 40 large T antigen driven by different promoters or enhancers. Two of the four lines developed primitive neuroectodermal tumors (PNETs) in the brain stem or pineal gland. A third TGM line developed retinoblastomas (a PNET-like tumor of the retina) as well as PNETs in the mesencephalon, while the fourth TGM developed retinoblastomas and adrenal pheochromocytomas. EXPERIMENTAL DESIGN: The expression of developmentally regulated polypeptides specific for the neuronal or glial lineage was examined in these PNETs using immunohistochemistry and Western blotting. RESULTS: Neoplastic cells in all of the PNETs exhibited neuronal, but no glial specific markers as evidenced by the invariable expression of synaptophysin, but no detectable glial fibrillary acidic protein or myelin basic protein. PNETs with a more differentiated neuronal phenotype expressed multiple neuronal polypeptides. The phenotypic properties of these PNETs closely resembled those found in human brain PNET biopsy samples and cell lines derived therefrom. CONCLUSIONS: We conclude that Simian virus 40 T antigen-induced PNETs in TGM exhibit the molecular phenotype of developing neurons or neuronal progenitor cells. Although many factors could influence the phenotype of these experimental PNETs (e.g., promoter, site of integration of the transgene) these PNETs appear to be suitable TGM models of human PNETs of the central nervous system.

Adrenal Gland Neoplasms↗