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Biomedical subjects

S Nori

Publications and source records attributed to S Nori.

18 recordsLinked to original sources
PubMed2005

Tumour proliferation, angiogenesis, and ploidy status in human colon cancer.

AIMS: Tumour angiogenesis is essential for carcinogenesis and facilitates the process of tumour development and metastasis. Vascular endothelial growth factor (VEGF) is a well characterised angiogenetic factor and is known to play a crucial role in new vessel development. To gain further insight into the effects of microvessel density and VEGF expression in colon cancer, their relation with tumour proliferation, ploidy status, and p53 expression was investigated in colon cancer. METHODS: Tissue samples of 50 archived colon cancers were analysed by immunohistochemistry for VEGF, p53, and the endothelial cell marker, von Willebrand factor (VWF), using specific antibodies. The same samples were re-cut for flow cytometric studies to obtain S phase fraction (SPF) and ploidy status. RESULTS: A positive significant correlation was found between SPF and angiogenesis. The median microvessel count in high SPF tumours was significantly higher than in low SPF ones. No association was found between VEGF expression and SPF. A positive correlation was found between ploidy status and p53 expression and microvessel count. Furthermore, a positive correlation was established between DNA ploidy, VEGF expression, and microvessel count. CONCLUSION: This study provides evidence that in colon cancer, tumour growth may be stimulated by vascular supply, and the lack of a correlation between tumour cell proliferation and VEGF expression indicates that these two parameters may be regulated by separate mechanisms. Furthermore, the positive correlation between microvessel density, VEGF expression, and ploidy status provides more evidence that genetic alterations are involved in tumour angiogenesis.

Adult↗
PubMed1998

The molecular and phenotypic profile of primary central nervous system lymphoma identifies distinct categories of the disease and is consistent with histogenetic derivation from germinal center-related B cells.

Primary central nervous system lymphoma (PCNSL) is a major cause of morbidity and mortality among human immunodeficiency virus (HIV)-infected individuals. The precise histogenetic derivation and the molecular pathogenesis of PCNSL is poorly understood. In an attempt to clarify the histogenesis and pathogenesis of these lymphomas, 49 PCNSL (26 acquired immunodeficiency syndrome [AIDS]-related and 23 AIDS-unrelated) were analyzed for multiple biologic markers, which are known to bear histogenetic and pathogenetic significance for mature B-cell neoplasms. PCNSL associated frequently (50.0%) with mutations of BCL-6 5' noncoding regions, which are regarded as a marker of B-cell transition through the germinal center (GC). Expression of BCL-6 protein, which is restricted to GC B cells throughout physiologic B-cell maturation, was detected in 100% AIDS-unrelated PCNSL and in 56.2% AIDS-related cases. Notably, among AIDS-related PCNSL, expression of BCL-6 was mutually exclusive with expression of Epstein-Barr virus (EBV)-encoded latent membrane protein (LMP)-1 and, with few exceptions, also of BCL-2. All but one PCNSL expressed hMSH2, which among mature B cells selectively stains GC B cells. These data suggest that PCNSL may be frequently related to GC B cells and may be segregated into two major biologic categories based on the expression pattern of BCL-6, LMP-1, and BCL-2. BCL-6(+)/LMP-1(-)/BCL-2(-) PCNSL occur both in the presence and in the absence of HIV infection and consistently display a large noncleaved cell morphology. Conversely, BCL-6(-)/LMP-1(+)/BCL-2(+) PCNSL are restricted to HIV-infected hosts and are represented by lymphomas with immunoblastic features. These data are relevant for the pathogenesis and histogenesis of PCNSL and may be helpful to segregate distinct biologic and prognostic categories of these lymphomas.

B-Lymphocyte Subsets↗
PubMed1997

Utilization of intraoperative electroneurography to understand the innervation of the trapezius muscle.

The radical neck dissection is an operation for the management of lymph node metastases from primary sites involving the oral cavity, larynx, and other areas of the head and neck. In this procedure, the spinal accessory nerve is removed along with other structures. In modified neck dissection the spinal accessory nerve is preserved. Patients undergoing the modified neck dissection have had variable functional outcomes from little or no pain or disability, to significant muscle dysfunction. Our group hypothesized that patients with good functional outcomes following modified neck dissection may have had motor contributions from C2, C3, or C4 branches, while those with less favorable outcomes did not. To demonstrate the presence of motor input and its significance both from the spinal accessory nerve and the branches of the cervical plexus, we utilized intraoperative electroneurography. We find that although there is motor contribution from C2, C3, and C4 to the trapezius muscle, it was not consistent or significant.

Cervical Plexus↗
PubMed1997

Immunohistochemical and in situ hybridization detection of growth-hormone-producing cells in human thymoma.

We have studied 25 thymomas by both immunohistochemistry and in situ hybridization for the presence of growth hormone (GH)-producing cells. Our results indicate that 1) GH-immunoreactive cells were present in 13 of 17 thymomas of cortical and predominantly cortical type but not in medullary (spindled) thymomas (n = 3) or low- to high-grade thymic carcinomas (n = 5), 2) GH-positive cells were mainly located at the periphery of the neoplastic lobules, at the periphery of the perivascular spaces and in the areas of medullary differentiation, 3) cells containing GH mRNA appeared at locations similar to those of GH-immunoreactive cells, and 4) GH-immunoreactive material was present only in the epithelial cell component as revealed by immunoelectron microscopy. In conclusion, this paper demonstrates the occurrence of GH-producing cells in noncarcinoid thymic tumors. The relevance of GH in thymoma cell biology requires additional investigations.

Adult↗
PubMed1996

Distribution of elastic fiber types in the epiphyseal region.

Three types of elastic fibers have been described: mature elastic fibers, elaunin fibers, and oxytalan fibers. To our knowledge, their location in the immature epiphysis has never been previously reported. The aim of the present study was to use histochemistry, immunohistochemistry, and electron microscopy to demonstrate the distribution of each type of elastic fiber in the epiphyseal region of growing humans and rabbits. Histological samples were collected from the knees of 10 immature New Zealand White rabbits and four children of various ages. The Weigert resorcin-fuchsin, Gomori aldehyde-fuchsin, Verhoeff iron haematoxylin, and Fullmer-Lillie methods were used for histochemistry; anti-elastin monoclonal antibodies, for immunohistochemistry; and tannic acid, uranyl acetate, and lead citrate stain, for transmission electron microscopy analysis. Elastic fibers were detected in the perichondrium, the epiphyseal vessels, and the outer and middle zones of Ranvier's groove. Their orientation was longitudinal in the outer zone and circumferential in the middle zone of the groove. Oxytalan fibrils (i.e., bundles of filaments of 10-12 nm in diameter that do not contain elastin) and elaunin fibers (i.e., filaments that cross discontinuous aggregates of elastin) were more plentiful in the middle zone and decreased with age, whereas mature fibers were more numerous in the outer zone and increased with age. This organization of elastic fibers seems to indicate an age-related process of maturation of the elastic network. The contribution of these fibers to the mechanical properties of the epiphyseal plate and to the growth process remains to be determined.

Age Factors↗
PubMed1996

Calretinin immunoreactivity in human sympathetic ganglia.

Calretinin is an "EF-hand" calcium-binding protein involved in the maintenance of intracellular calcium ion homeostasis. This study was undertaken to investigate the presence of calretinin in human lumbar paravertebral sympathetic ganglia from subjects of different ages (26-85 years) using immunohistochemical and immunoblotting methods. Calretinin-like immunoreactivity was found in a subpopulation of postganglionic sympathetic neurons, whose percentage decreased progressively with aging by about 50% (63% of immunoreactive neurons at < or = 40 years; 29% at > or = 81 years) whereas the neuronal density remained basically unchanged. Calretinin-like immunoreactivity showed a granular pattern of cytoplasmic distribution suggesting preferential localization of this protein associated with intracellular membranes. Occasionally diffuse cytosolic labelling was also observed. The immunoblotting demonstrated a protein band with an estimated molecular weight of 30 kDa, approximately. Present results provide, for the first time, evidence for the presence of calretinin in human paravertebral sympathetic ganglia. Since the number of calretinin-like immunoreactive neurons decreased significantly with aging our findings suggest an involvement of this protein in the age-dependent impairment of sympathetic function.

Adult↗
PubMed1995

The use of cyanoacrylate tissue adhesive in high-risk intestinal anastomoses.

The success of every intestinal surgical procedure primarily depends on correct technical execution of the intestinal sutures. Despite the continuing improvements in intestinal synthesis techniques and the introduction of mechanical staplers, the risk of anastomotic dehiscence remains a major concern. For high-risk anastomoses, defined as those performed under critical conditions, n-butyl-2-cyanoacrylate tissue adhesive allows for quick sealing of the two stumps and supports the physiological wound-healing process. Furthermore, no experimental or clinical studies have shown that this glue has any carcinogenic or mutagenic properties. Thus, we believe that n-butyl-2-cyanoacrylate will be extremely useful for intestinal anastomoses with a high risk of dehiscence.

Anastomosis, Surgical↗
PubMed1995

Stereopsis and binocularity in the squirrel monkey.

The squirrel monkey lacks anatomically demonstrable ocular dominance columns, and physiologically it has an ocular dominance distribution in V1 that is very different from that of macaques, with far fewer cells that strongly favor one eye over the other. We tested an alert squirrel monkey for physiological responses to stereoscopic stimuli by measuring evoked potentials in response to cytclopean patterns generated in dynamic random-dot stereograms. The monkey showed evoked responses both to changes in disparity and to shifts between correlation and uncorrelation between the two eyes. This result strongly suggests that the squirrel monkey can detect stereoscopic depth, which in turn casts some doubt on the assumption that ocular dominance columns bear an important relation to stereopsis.

Animals↗
PubMed1995

Use of [123I]MIBG to assess cardiac adrenergic innervation: experience in hypertensive cardiopathy and left ventricular aneurysms.

[123I]MIBG has been proposed as a suitable tracer of the adrenergic system of the heart. The aims of this study was to investigate the adrenergic functional status of the heart in hypertensive patients with left ventricular hypertrophy (LVH), and to evaluate the distribution of neuroadrenergic terminals in patients with left ventricular aneurysms (LVA) presenting complex arrhythmias. We studied 21 patients (4 normals, 11 with LVH and hypertension, and 6 with previous myocardial infarction, LVA and complex arrhythmias) who underwent series of [123I]MIBG planar scans (from 0.5 to 24 hours p.i.) and SPECT scans using both [123I]MIBG and 201Tl. Data quantification was performed by calculating the heart/mediastinum ratio (planar scan) and the percent uptake in 5 myocardial regions (SPECT scan). No significant differences between normals and hypertensive patients were found either in the heart/mediastinum ratio or in the regional distribution of [123I]MIBG and 201Tl. In hypertensive patients the uptake of [123I]MIBG was significantly higher than that of 201Tl in the septal wall while in the lateral and inferior walls it was significantly lower. In patients with anteroapical myocardial infarction (MI), the size of the [123I]MIBG defect was slightly smaller than the 201Tl defect; moreover a constant, severe [123I]MIBG defect was observed in the inferior walls whereas 201Tl uptake was normal. We conclude that while in hypertensive patients adrenergic innervation seems to be slightly impaired as compared to myocardial perfusion, in patients with MI a large area of functional or anatomical denervation may be detected despite the preserved perfusion and viability; this mismatch may be the trigger of complex arrhythmias.

3-Iodobenzylguanidine↗
PubMed1992

The ultrastructure of peripheral neurofibroma: the role of mast cells and their interaction with perineurial cells.

The authors analyze the ultrastructure of mast cells and perineurial cells when both are present in neurofibroma of the nerve sheath. Samples of pathologic tissue taken from three patients with neurofibroma of a peripheral nerve sheath were analyzed by light and transmission electron microscopy. The observations document the characteristics of the tumor cells (Schwann cells and perineurial cells) as well as the presence of numerous mast cells, typically in close contact with the perineurial cells and never with the Schwann cells. Many electron-dense vesicles were found between the cells; these vesicles are created when the cell membrane of the mast cell buds, and then they come into contact with the adjacent perineurial cell. Endocytosis vesicles are often present in the cytoplasm of perineurial cells. Analysis of these observations led the authors to assume the existence of a metabolic interaction between the two cell type in contact with each other and an active role of the mast cells in the evolution of the tumor. The following two theories are plausible: either the mast cells actively stimulate tumor growth, or they alter the phenotype of the tumor cell. These findings could have interesting clinical applications. The use of treatment protocols which inhibit mast cell activity could, in theory, stop either the proliferation of the neurofibroma or its malignant transformation.

Cell Division↗
PubMed1992

Ultrastructural analysis of the adaptation of articular cartilage to mechanical stimulation.

Ultrastructural analysis was conducted on samples of articular cartilage taken from both load-bearing and non-load-bearing areas with the aim of evaluating the morphologic adaptation of the articular cartilage to mechanical stimulation and identifying the mechanisms of interaction of the chondrocyte and the matrix. Through this analysis we were able to better define the adaptation process of the cartilage as well as the modalities of mechanical stress transmission. We believe that the complex formed by the chondrocyte, the pericellular matrix, and the pericellular capsule constitutes the biomechanical unit of the articular cartilage which serves as the sensor and transducer of mechanical stress. The arrangement of the collagen fibers and the proteoglycans which make up the pericellular capsule and membrane around the chondrocyte can be compared, from a mechanical standpoint, to a dynamic structure constructed in order to absorb the load stresses and protect the internal environment. From a biological standpoint, these are comparable to an extracellular-scaffold constructed with the aim of mediating the interaction between the chondrocyte and the territorial and inter-territorial compartments.

Adaptation, Physiological↗
PubMed1991

The ultrastructure of schwannoma and neurofibroma of the peripheral nerves.

An electron microscopic study of 4 solitary schwannomas and 2 neurofibromas of peripheral nerves was performed with the aim of investigating the debated histogenesis of the two types of lesion. Our observations confirm that solitary schwannoma is composed almost exclusively of cells with characteristics of differentiated Schwann cells, thus providing evidence for a neuroectodermal origin of the tumor. Analysis of the ultrastructure of neurofibroma shows the presence of 3 different types of cells: Schwann-like cells, perineurial-like cells, and fibroblast-like cells. Perineurial-like cells were prevalent in our observations. These findings as well as the many controversial aspects of the origin of neurofibroma could be explained by separating this type of neoplasia into two pathological forms: perineurial and interstitial. Moreover, the numerous differences between solitary schwannoma and neurofibroma allow us to hypothesize a different cellular origin for each tumor. If confirmed by further observations, this would explain the difference in the capacity of the two types of neoplasia to undergo malignant change, an occurrence almost unknown in solitary schwannoma yet relatively common in neurofibroma.

Collagen↗
PubMed1990

Axillary lymphadenectomy. A prospective, randomized trial of 13 factors influencing drainage, including early or delayed arm mobilization.

Greater amount and duration of postoperative wound drainage after lymphadenectomy impede healing. We evaluated the influence of early vs delayed initiation of shoulder mobilization on postoperative drainage. Fifty-seven women with clinical stage I or II breast cancer were randomized to either early (postoperative day 2) or delayed (postoperative day 5) shoulder motion. Early vs delayed time of exercise initiation had no effect on total amount or duration of drainage, either as an inpatient or outpatient. The two groups were determined to be homogeneous as to age, breast size, weight, height, obesity, previous biopsy, excision of pectoralis minor, excision of thoracodorsal complex, level of axillary dissection, total number of lymph nodes, number of positive lymph nodes, lymphatic vessel invasion (with negative lymph nodes), and whether the dominant hand was on the side operated on. The two factors predicting greater drainage were large numbers of positive lymph nodes and no previous surgical biopsy (as in one-step procedure).

Arm↗
PubMedDate not supplied

Innervation of the trapezius muscle by the intra-operative measurement of motor action potentials.

Although the surgical anatomy of the spinal accessory nerve and the cervical plexus has been extensively described, the exact motor innervation of the trapezius has been controversial. Attempts to resolve this question have involved anatomic or electrophysiologic studies in human embryos and animals. Extrapolation of the results to adult humans may not be correct. Accurate identification of muscle innervation is obtainable by intra-operative measurement of motor action potentials produced by direct stimulation of the accessory nerve and the cervical plexus. The study involved 14 patients undergoing supraomohyoid or modified neck dissections. Under direct vision, stimulating electrodes were placed on the identified nerves and motor action potentials, and latencies were recorded by surface electrodes placed over the three portions of the trapezius. In 13 patients, when the accessory nerve was stimulated, motor action potentials were obtained in 13 of 13 in the first portion, 11 of 13 in the second portion, and 10 of 13 in the third portion of the trapezius. In the last patient, the accessory nerve ended in the sternocleidomastoid muscle, and innervation of the trapezius was via C3 as demonstrated by motor action potentials. Responses when the roots of the cervical plexus were stimulated varied. Three patterns were seen: In the first group (seven patients), motor action potentials were distinct from those recorded when the accessory nerve was stimulated. Additionally, latencies were different from those of the accessory nerve. The second group (four patients) had motor action potentials that were similar to those obtained from stimulation of the accessory nerve, although their corresponding latencies were different.(ABSTRACT TRUNCATED AT 250 WORDS)

Accessory Nerve↗
PubMedDate not supplied

Coexpression of mRNAs for P2X1, P2X2 and P2X4 receptors in rat vascular smooth muscle: an in situ hybridization and RT-PCR study.

The expression of mRNAs for three P2X receptor subtypes (PX21, P2X2, P2X4) in the rat vascular system was studied by in situ hybridization and RT-PCR. In heart sections mRNAs transcripts for all three receptors were colocalized in smooth muscle cells of coronary vessels, while no specific positivity was apparent in myocardium. Coexpression of P2X receptor mRNA transcripts were also observed in other peripheral vessels, including aorta, pulmonary artery, internal and external iliac arteries, renal artery and femoral artery. By contrast, no mRNA transcripts of the above receptors were found in the superior mesenteric artery. RT-PCR performed on microdissected tissues (coronary arteries, aorta and myocardium from various heart areas) confirmed the presence of P2X1, P2X2 and P2X4 receptor mRNAs. Furthermore, in the same tissues two splice variants of the P2X2 receptor were identified. These results reveal an important molecular heterogeneity of P2X receptors, thus substantiating the possibility of a heteropolymeric assembly of ATP-gated ion channels in the cardiovascular system.

Animals↗
PubMedDate not supplied

Polymeric glues in intestinal surgery.

Authors reports the results of an experimental study on the usefulness of n-butyl-2-cyanoacrylate in abdominal surgery. The research, performed on Wistar rats and Landrace pigs, is constituted by an early phase, to verify the tissue reaction to the n-butyl-2-cyano-acrylate and its adhesive properties, and a main phase, in which it was evaluated the efficacy of n-butyl-2-cyano-acrylate as the only support or as an adjunct to the usual methods in intestinal synthesis. histological and angiographic examination of the surgical specimens demonstrated the tissue autotoxicity and the good adhesive effect of the tissue glue. Because of these characteristic, authors propose its employment to reinforce intestinal sutures performed with the usual methods in high risk condition.

Animals↗