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M Corti

Publications and source records attributed to M Corti.

At least 19 recordsLinked to original sources
PubMed2006

Capillary blood viscosity in microcirculation.

As known, at the arteriolar level there is the highest resistance to the flow due to the section and to the velocity with an average pressure fall of 50 mmHg (from 85 to 35 mmHg). This resistance is expressed in sec(-1) by the ratio W/2r. This ratio is very high with an average value of 332 sec(-1) and viscosity at this high shear-rate is negligible. At the capillary level the pressure fall is 11.5 mmHg but the vascular resistance W/2r is much lower, on average 32 sec(-1). We can say that if a resistance of 333 sec(-1) corresponds with a pressure fall of 50 mmHg, then a resistance of 32 sec(-1) should correspond with a pressure fall of 4.8 mmHg. The highest pressure fall is due to another kind of resistance which we can define as "Capillary Blood Viscosity" because it depends on the rheological and structural characteristics of the blood. Our instrument reproduces the structure of the capillary district in an experimental model and measures the General Blood Viscosity (GBV) and the Capillary Blood Viscosity (CBV) at the same shear-rate and in particular at the low shear-rate when in non-Newtonian fluids the highest increase in viscosity appears. Consequently, at the capillary, viscosity is dominant with respect to the other geometric and physical resistances. Moreover, the percentage ratio between the GBV and the CBV gives a physical measure of erythrocyte deformability. Knowing viscosity at shear-rate present in the circulatory system, we can obtain the size of RBCs aggregates in the different circulatory districts and their characteristics expressed like "aggregation bond". Changes in CBV are the only possibility in clinical practice to improve the circulatory flow in the capillary district because it is not sure that changes in the arteriolar section can improve the capillary flow or rather open arterio-venous anastomosis. Moreover, in the systemic circulation the aggregate size allows us to point out the phenomenon of cell adhesion because the presence of several receptors involves also the other blood cells. Finally the size and the stability of the RBCs aggregates can modify the endothelial thrombo-resistance.

Arthritis, Rheumatoid↗
PubMed2006

Biomechanics of lower limb raising from the supine position.

AIM: This study analyses the kinematics of the lower limb raising movement from the supine position and the electromyography activity of the muscles involved. METHODS: Twenty healthy right hand subjects performed the right lower limb raising from the supine position, starting from the clinical bed plane and up to a 70 degrees inclination of the thigh over the horizontal plane, while the knee was kept flexed at 120 degrees by a soft splint. The same exercise was executed with no resistance and with 2 kg and 8 kg respectively applied to the ankle. The kinematics was recorded utilising an optoelectronic system, whereas the electromyography activity was recorded by a surface electromyography (EMG) applied to the following muscles: right rectus femoris, left biceps femoris, rectus abominalis from both sides and dorsal major from both sides. RESULTS: In all the cases the pelvis performed a backwards rotation retroversion. The highest increase of EMG activation was recorded on the right rectus femoris as well as on the left biceps femoris; the increase was lower in the right rectus abdominis and in the right dorsal major, whereas it was minimum in the left rectus abdominis and in the left dorsal major. A great variability in the activation times was reported in the various muscles of the different subjects, regardless of the trials. The only muscle anticipating the right rectus femoris activation was the left biceps femoris. CONCLUSIONS: The research has shown how the simple movement under study is more complex than what is usually described by the text books, both in regard to the kinematics and to muscles' actions. Even the individual variability in utilising the agonist and stabilisation muscles can be of relevance for a more rational utilisation of the physical exercise in motor re-education.

Adult↗
PubMed2003

Cytogenetics of the genus Arvicanthis (Rodentia, Muridae). 3. Comparative cytogenetics of A. neumanni and A. nairobae from Tanzania.

The African rats of the genus Arvicanthis have been widely studied during recent years to clarify species boundaries and phylogenetic relationships. The wide chromosomal variability of the genus has been highlighted in several studies, with each accepted species characterised by its individual karyotypes and others being revealed as cryptic species. In the present paper we report the karyotype and the C- and G-banding patterns of the two species A. nairobae and A. neumanni from seven localities of Tanzania, an area of the range poorly studied. The two karyotypes were compared to that of A. niloticus, which is considered to be primitive. The karyotype of A. neumanni is characterised by 2n = 53-54 and NFa = 62. This karyotypic variability depends on a widespread Robertsonian polymorphism. The karyotype of A. nairobae shows 2n = 62 and NFa = 78; it diverges from that of A. niloticus through one reciprocal translocation, five inversions and three heterochromatic additions. The comparison with the karyotypes of other species of the genus showed that A. neumanni belongs to the east African lineage (with A. abyssinicus, A. blicki, A. niloticus), while A. nairobae is closer to the central and the west African representatives which were all previously under the name of A. niloticus (ANI-2, ANI-3, ANI-4). The distribution of A. nairobae in east Africa opens new scenarios in the biogeographical pattern of evolution of the genus.

Animals↗
PubMed2003

HCV recovery from peripheral blood mononuclear cell culture supernatants derived from HCV-HIV co-infected haemophilic patients with undetectable HCV viraemia.

Hepatitis C viraemia, in 38 human immunodeficiency virus positive (HIV+)/hepatitis C virus positive (HCV+) patients, was determined in haemophilic patients during the 4 years since initiation of highly active antiretroviral therapy (HAART). Six of 38 patients had persistently HCV-negative viraemia for more than 2 years. No correlation between HCV-negative viraemia and CD4+ T-cell counts, HIV viral load, age, type or severity of haemophilia could be established. Reduced levels of HIV viral load and the immune reconstitution that follows the initiation of HAART were not enough to explain the disappearance of HCV from plasma. Individuals who cleared plasma HCV had significantly higher CD8+ T-cell counts (P=0.0013) (mean +/- SE: 1153 +/- 117.8 cells microL(-1)) than those with HCV-positive viraemia (819.1 +/- 40.72 cells microL(-1)). Because HCV could maintain a low replication level in peripheral blood mononuclear cells (PBMC), we cultured PBMC of five of six patients with undetectable HCV viraemia. We found four of five HCV RNA-positive cultures. The presence of HCV RNA in our cultures proved that these cells may be an important viral reservoir that could contribute to HCV recurrence in plasma even after long periods of negative viraemia. In summary, our results indicate that in spite of prolonged HCV-negative plasma viraemia, HCV patients that are co-infected with HIV may harbour replication-competent HCV in their PBMC. Therefore, true clearance of HCV infection is difficult to achieve in these patients.

Adult↗
PubMed2003

[Primary esophageal lymphoma in a patient with AIDS].

Primary esophageal lymphomas are extremely rare. We report a primary esophageal T cell lymphoma of a diffuse large cell phenotype B in a patient with AIDS. Also we reviewed other published cases. The diagnosis of this complication should be considered in HIV seropositive patients with progressive displagia and endoscopic findings of masses, polyps or ulcerations and, specially in those unresponsive to antifungal or antiviral therapy. Biopsy and histopathologic studies are needed to confirm the diagnosis.

Adult↗
PubMed2003

[The compromise of esophagus in HIV/AIDS diseases].

Esophageal disease is a common complication in patients infected with human immunodeficiency virus type-1 (HIV-1). Dysphagia, odynophagia and retrosternal pain are the most common symptons associated with the esophageal compromise. Esophageal candidiasis, the most frequent opportunistic infection, may occur in patients with long-standing infection or may be a manifestation of the seroconversion. Cytomegalovirus and Herpes simplex virus are more likely to produce esophageal ulcers or erosions. HIV itself may be responsible for ulcerative esophagitis. Neoplasms as Kaposi's sarcoma, are an infrequent cause of symptomatic disease. Barium esophagography and specially upper endoscopy are the most commonly employed diagnostic modalities for the evaluation of symptomatic patients. Endoscopy may be warranted to make a rapid diagnosis such that specific therapy will not be delayed. The use of a combination of histologic, cytologic, mycologic and virologic studies is necessary to provide an etiologic diagnosis of these lesions.

AIDS-Related Opportunistic Infections↗
PubMed2002

Chromosomal characterization of Arvicanthis species (Rodentia, Murinae) from western and central Africa: implications for taxonomy.

A chromosome study of unstriped grass rats of the genus Arvicanthis (Rodentia, Murinae) in western and central Africa is presented. The observations extend the data available to 242 specimens from 59 localities. All individuals karyotyped belong to four karyotypic forms, or cytotypes, earlier described as ANI-1, ANI-2, ANI-3, and ANI-4 and are presumed to correspond to four distinct species. In order to provide diagnostic characters for these western and one central African Arvicanthis species, we standardized the chromosomal data available and developed a G- and C-banded chromosome nomenclature that allows easy species identification. Each form is characterized by a distinct geographical distribution, roughly following the biogeographical domains of western Africa, although their precise limits remain to be assessed. The sole area of sympatry detected is the region of the inner delta of the Niger River, where both ANI-1 and ANI-3 can be found. It is proposed that the three western African species ANI-1, ANI-3, and ANI-4 be renamed as A. niloticus, A. ansorgei, and A. rufinus, respectively.

Animals↗
PubMed2001

Endocytosis and signaling cascades: a close encounter.

Internalization of receptors and other cell surface components is well known to occur via clathrin-mediated endocytosis, although other less well characterized pathways are also involved. Internalized receptors are then delivered to early endosomes, where they are sorted to be recycled back to the plasma membrane for reutilization or transported to late endosomes/lysosomes for degradation. Endocytosis has long been considered as a constitutive, housekeeping function of animal cells that occurs independently of the cellular environment in contrast to regulated secretion. Here, we will discuss recent studies that are uncovering the existence of cross-talk between signaling molecules and components of the transport machinery, indicating that endocytosis can be modulated by signaling pathways.

Actins↗
PubMed2001

TNF-alpha, PDGF, and TGF-beta(1) expression by primary mouse bronchiolar-alveolar epithelial and mesenchymal cells: tnf-alpha induces TGF-beta(1).

The bronchiolar-alveolar epithelium (BAE) is a primary target site for inhaled agents that cause lung injury. These cells, consequently, release a broad range of mediators that influence other cell populations, including interstitial lung fibroblasts that are central to the development of interstitial pulmonary fibrosis (IPF). A number of peptide growth factors (GF) have been postulated to be essential in the pathogenesis of IPF. We demonstrate here that primary populations of mouse BAE and mesenchymal cells, maintained in culture, synthesize four potent GF. These are platelet-derived growth factor isoforms (PDGF) A and B, transforming growth factor beta-1 (TGF-beta(1)), and tumor necrosis factor alpha (TNF-alpha). A mouse lung epithelial cell isolation technique pioneered in this laboratory has been used to purify the BAE cells to greater than 85% (80 +/- 5.6% alveolar type II and 9 +/- 2.3% Clara cells) in culture. Northern analysis, RNase protection assay, and immunocytochemistry (ICC) were used to establish mRNA and protein expression of the GF over time in the cultured BAE and mesenchymal cells. We show for the first time in these primary mouse lung cells that treatment of both cell types with TNF-alpha upregulates expression of TGF-beta(1). The four GF are produced by both epithelial and mesenchymal cells but with different temporal patterns. TGF-beta(1) is expressed constitutively by BAE and mesenchymal cells, whereas TNF-alpha expression wanes over time. The findings by ICC were consistent with levels of mRNA expression in both cell types. As genetically defined and altered mouse strains are becoming increasingly valuable for modeling lung disease, studying the gene expression patterns of target cells from these animals in vitro would be useful in sorting out the complex responses by individual cell types of the lung and the interactions among the multitude of mediators that are released during lung cell injury.

Animals↗
PubMed2001

[Eye involvement in AIDS-related Kaposi sarcoma].

BACKGROUND: The study evaluates the incidence of ocular compromise in the Kaposi's sarcoma associated with AIDS. METHODS: We revised the clinical histories of HIV seropositives patients seen in the ophthalmology department from January, 1994 to December, 1998. All patients were examined by direct visually and dilated fundus examination with the use of either a direct or an indirect ophthalmoscope. RESULTS: In 6,552 patients, ocular Kaposi's sarcoma was diagnosed in 17 (0.25%), predominantly in male sex (88.23%). The lesions predominated in eyelids, and the inferior has been the most affected. In only one female, the ocular compromise was the first neoplastic manifestation. CONCLUSIONS: The ocular compromise in the Kaposi's sarcoma is an alternative to be considered in AIDS patients with previous or simultaneous cutaneous or visceral involvement. Due to the few clinical signs of these lesions, a thorough ocular study is recommended in these patients.

Acquired Immunodeficiency Syndrome↗
PubMed2001

Molecular phylogeny of Myomys/Stenocephalemys complex and its relationships with related African genera.

Partial 16S rRNA mitochondrial gene sequences were used to infer the phylogenetic relationships among Stenocephalemys albocaudata, S. griseicauda and Myomys albipes, three closely related Ethiopian endemic murines and a selection of related species (Myomys daltoni, Praomys delectorum, Mastomys natalensis, Hylomyscus kaimosae, and Colomys goslingi) from other African regions. The obtained phylogeny confirms the close relationship between M. albipes and the two Stenocephalemys species, but it also suggests that both the genera Myomys and Stenocephalemys are paraphyletic, as M. albipes is closer to Stenocephalemys than to M. daltoni and S. griseicauda is more closely related to M. albipes than to S. albocaudata. These data, if confirmed, would argue that M. albipes should be renamed S. albipes. In conclusion, our study suggests that morphological similarity is not always a reliable measure for close genetic relationship in murines. Morphological similarity among species that evolved under similar ecological conditions can be the result of convergent evolution rather than a consequence of recent common ancestry.

Journal Article↗
PubMed2001

The stress-induced MAP kinase p38 regulates endocytic trafficking via the GDI:Rab5 complex.

Early endocytic membrane traffic is regulated by the small GTPase Rab5, which cycles between GTP- and GDP-bound states as well as between membrane and cytosol. The latter cycle depends on GDI, which functions as a Rab vehicle in the aqueous environment of the cytosol. Here, we report that formation of the GDI:Rab5 complex is stimulated by a cytosolic factor that we purified and then identified as p38 MAPK. We find that p38 regulates GDI in the cytosolic cycle of Rab5 and modulates endocytosis in vivo. Our observations reveal the existence of a cross-talk between endocytosis and the p38-dependent stress response, thus providing molecular evidence that endocytosis can be regulated by the environment.

Amino Acid Substitution↗
PubMed2001

[HIV infected macrophages isolated from HIV+ patients with undetectable viral load undergoing combined antiretroviral treatment].

A new method of culture of peripheral blood leukocytes (PBMC) from HIV+ patients, in the absence of exogenous stimuli (allogeneic cells or cytokines) (PBMC w/s) was used for the detection of persistent viral infection in HIV patients who had undergone successful highly active antiretroviral therapy (HAART) lowering their viral burden to undetectable levels (< 50 RNA copies/ml). Infected cells were always of the monocyte/macrophage lineage (M). No infection could be detected in these patients using the classical system (co-culture with HIV-CMP activated with PHA and IL-2). Differences in the class of target cells (higher proportion of proliferating M and CCR5 expressing cells in the PBMC w/s system than in PBMC-PHA cultures) may determine the relative sensitivity of each technique to achieve successful isolation of HIV from different patients.

Antiretroviral Therapy, Highly Active↗
PubMed2001

[Disseminated infection due to strongyloides stercoralis in AIDS patients. A report of 2 cases].

Strongyloides stercoralis is an intestinal nematode that infects humans worldwide. Infected patients with severe involvement of cellular immunity may develop a syndrome characterized by the dissemination of larvae throughout the body. Extraintestinal strongyloidiasis has been infrequently reported and despite the prevalence of the helminth in tropical and developing countries there are few cases reported in AIDS patients. Most patients with disseminated strongyloidiasis present with fever, cough, diarrhea and shortness of breath. Chest radiographs usually show diffuse infiltrates. The diagnosis has been made by finding the helminth in respiratory secretions or stool. Enteric organisms like Escherichia coli can often be isolated in the blood or cerebrospinal fluid. We report two cases of disseminated strongyloidiasis in AIDS patients, in which stercoralis larvae were detected in sputum and stool samples.

AIDS-Related Opportunistic Infections↗
PubMed2000

Use of two-block partial least-squares to study covariation in shape.

The relatively new two-block partial least-squares method for analyzing the covariance between two sets of variables is described and contrasted with the well-known method of canonical correlation analysis. Their statistical properties, type of answers, and visualization techniques are discussed. Examples are given to show its usefulness in comparing two sets of variables--especially when one or both of the sets of variables are shape variables from a geometric morphometric study.

Analysis of Variance↗
PubMed2000

AIDS and Chagas' disease.

Chagas' disease can reactivate in patients with AIDS and present as a brain mass lesion or an acute diffuse meningoencephalitis indistinguishable from other opportunistic infections or neoplastic processes, such as toxoplasma encephalitis or central nervous system (CNS) primary lymphoma. The CNS tumor-like lesion is the most common manifestation of Chagas' disease reactivation in AIDS patients. The prognosis of untreated cases is grim and underscore the need for safe and effective therapeutic agents.

AIDS-Related Opportunistic Infections↗