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Biomedical subjects

A Torre

Publications and source records attributed to A Torre.

At least 19 recordsLinked to original sources
PubMed2002

[Simultaneous presence of antibodies against the glomerular basement membrane and anti-myeloperoxidase antibodies in 2 patients with rapidly progressive glomerulonephritis].

We report two patients with rapidly progressive glomerulonephritis without alveolar hemorrhage. Renal biopsy showed extracapillary glomerulonephritis with linear deposits of immunoglobulin G. Serologically anti-glomerular basement membrane antibodies (Ac AMBG) and ANCA anti-myeloperoxidase were present. All patients were treated with steroids, cyclophosphamide and plasma exchange. One patient needed dialysis, and other one died from a renal biopsy complication. We discuss the epidemiologic, pathogenic and prognostic aspects of this association.

Aged↗
PubMed2001

The heterogeneity of allergic phenotypes: genetic and environmental interactions.

OBJECTIVE: This article reinforces the reader's knowledge of the multifactorial nature of allergic diseases and of the heterogeneity of allergic phenotypes. DATA SOURCES: Personal studies and an evidence-based approach is used to support the assumption that three major abnormalities concur in the pathophysiology of allergic diseases: 1) enhanced allergen recognition and specific immune response; 2) a T helper 2 cytokine profile that results in polyclonal immunoglobulin E activation and mast cell-eosinophilic inflammation; and 3) organ hyperreactivity. STUDY SELECTION: Examples of genetic and environmental factors that preferentially influence each of these distinct pathophysiologic abnormalities are provided. RESULTS: Data presented indicate that allergic diseases distribute along a wide spectrum depending on the preferential pathophysiologic abnormalities operating in the individual patient. CONCLUSIONS: Categorization of allergic patients into distinct clinical phenotypes might result in a more patient-oriented (rather than disease-oriented) approach, and hence, better management.

Allergens↗
PubMed2001

Frequency and determinants of microalbuminuria in mild hypertension: a primary-care-based study.

OBJECTIVE: To evaluate the frequency of microalbuminuria and its relationship with several risk factors and left ventricular mass in a population of mildly hypertensive subjects attended in a primary-care setting. DESIGN: Cross-sectional study. SETTING: Eight primary-care centres. PATIENTS: Two hundred and twenty-three non-diabetic patients recently diagnosed with mild hypertension were included in the study. None of them had clinical evidence of target-organ damage or had received prior antihypertensive treatment. INTERVENTIONS: Subjects included in the study underwent clinical interview, measurement of blood pressure (BP) on three visits, blood analysis, measurement of albumin by immunonephelometry in three overnight urine collections, 24 h BP monitoring and M-mode and Doppler echocardiography. MAIN OUTCOME MEASURES: Tobacco habit, clinic BP, body mass index, serum lipids and uric acid, glycaemia, urinary albumin excretion (UAE), ambulatory BP and left ventricular mass index. RESULTS: The frequency of microalbuminuria was 7.2%. Microalbuminuric patients were more likely to be men and to be characterized by higher ambulatory BP, body mass index and uric acid levels. Regression analysis demonstrated that male sex and 24 h systolic BP were determinants of UAE. Patients with white-coat hypertension showed lower UAE than did subjects with sustained hypertension. Although a certain relationship between UAE and left ventricular mass index was found, these variables were not significantly correlated. CONCLUSIONS: A low proportion of mildly hypertensive patients attended in a primary care setting are microalbuminuric. In this population, UAE is an expression of BP values over 24 h and correlates with several risk factors.

Adult↗
PubMed2000

Distinct antitumor properties of a type IV collagen domain derived from basement membrane.

Vascular basement membrane is an important structural component of blood vessels. During angiogenesis this membrane undergoes many alterations and these changes are speculated to influence the formation of new capillaries. Type IV collagen is a major component of vascular basement membrane, and recently we identified a fragment of type IV collagen alpha2 chain with specific anti-angiogenic properties (Kamphaus, G. D., Colorado, P. C., Panka, D. J., Hopfer, H., Ramchandran, R., Torre, A., Maeshima, Y., Mier, J. W., Sukhatme, V. P., and Kalluri, R. (2000) J. Biol. Chem. 275, 1209-1215). In the present study we characterize two different antitumor activities associated with the noncollagenous 1 (NC1) domain of the alpha3 chain of type IV collagen. This domain was previously discovered to possess a C-terminal peptide sequence (amino acids 185-203) that inhibits melanoma cell proliferation (Han, J., Ohno, N., Pasco, S., Monboisse, J. C., Borel, J. P., and Kefalides, N. A. (1997) J. Biol. Chem. 272, 20395-20401). In the present study, we identify the anti-angiogenic capacity of this domain using several in vitro and in vivo assays. The alpha3(IV)NC1 inhibited in vivo neovascularization in matrigel plug assays and suppressed tumor growth of human renal cell carcinoma (786-O) and prostate carcinoma (PC-3) in mouse xenograft models associated with in vivo endothelial cell-specific apoptosis. The anti-angiogenic activity was localized to amino acids 54-132 using deletion mutagenesis. This anti-angiogenic region is separate from the 185-203 amino acid region responsible for the antitumor cell activity. Additionally, our experiments indicate that the antitumor cell activity is not realized until the peptide region is exposed by truncation of the alpha3(IV)NC1 domain, a requirement not essential for the anti-angiogenic activity of this domain. Collectively, these results effectively highlight the distinct and unique antitumor properties of the alpha3(IV)NC1 domain and the potential use of this molecule for inhibition of tumor growth.

Angiogenesis Inhibitors↗
PubMed2000

Anti-angiogenic cues from vascular basement membrane collagen.

Vascular basement membrane is an important structural component of blood vessels and has been shown to interact with and modulate vascular endothelial behavior during angiogenesis. During the inductive phase of tumor angiogenesis, this membrane undergoes many degradative and structural changes and reorganizes to a native state around newly formed capillaries in the resolution phase. Such matrix changes are potentially associated with molecular modifications that include expression of matrix gene products coupled with conformational changes, which expose cryptic protein modules for interaction with the vascular endothelium. We speculate that these interactions provide important endogenous angiogenic and anti-angiogenic cues. In this report, we identify an important antiangiogenic vascular basement membrane-associated protein, the 26-kDa NC1 domain of the alpha1 chain of type IV collagen, termed arresten. Arresten was isolated from human placenta and produced as a recombinant molecule in Escherichia coli and 293 embryonic kidney cells. We demonstrate that arresten functions as an anti-angiogenic molecule by inhibiting endothelial cell proliferation, migration, tube formation, and Matrigel neovascularization. Arresten inhibits the growth of two human xenograft tumors in nude mice and the development of tumor metastases. Additionally, we show that the anti-angiogenic activity of arresten is potentially mediated via mechanisms involving cell surface proteoglycans and the alpha1beta1 integrin on endothelial cells. Collectively, our results suggest that arresten is a potent inhibitor of angiogenesis with a potential for therapeutic use.

Animals↗
PubMed2000

Identification of alpha3, alpha4, and alpha5 chains of type IV collagen as alloantigens for Alport posttransplant anti-glomerular basement membrane antibodies.

BACKGROUND: Alport syndrome is a hereditary disorder of basement membranes especially affecting the kidneys, ears, and eyes. Some patients who undergo renal transplantation lose their kidneys as a result of posttransplant anti-glomerular basement membrane (anti-GBM) disease. METHODS: In the present study, we analyzed serum from 21 unselected Alport patients who underwent renal transplantation. Eleven samples were from patients without posttransplant anti-GBM nephritis, and 10 were from patients with this disease. RESULTS: Thirteen serum samples [10 alport posttransplant nephritis serum (APTN) and three Alport posttransplant serum (APT)] revealed linear binding to the GBM by indirect immunofluorescence. By using direct ELISA and immunoblotting with GBM constituents and type IV collagen NC1 domains from bovine, human, and recombinant sources, we detected anti-GBM antibodies in all Alport patients in varying titers. Five samples showed specific reactivity to the alpha3 chain, four to the alpha5 chain, six to both alpha3 and alpha5 chains, one to the alpha3 and alpha4 chains, and two to the alpha3, alpha4, and alpha5 chains of type IV collagen. The varied spectrum of reactivities was present equally in nephritic and non-nephritic sera. Ten control samples from non-Alport transplant patients did not exhibit specific binding to the GBM. CONCLUSIONS: These results suggest that the absence of alpha3, alpha4, and alpha5 chains of type IV collagen in the Alport kidney leads to alloantibodies in all Alport patients who receive transplants, irrespective of whether they develop nephritis or not. Although all Alport transplant patients develop this humoral response, only a select few develop anti-GBM disease. We suggest that this difference could be attributable to a genotypic effect on the ability of some individuals to launch a cell-mediated immune response.

Animals↗
PubMed2000

Canstatin, a novel matrix-derived inhibitor of angiogenesis and tumor growth.

We isolated and identified an endogenous 24-kDa human basement membrane-derived inhibitor of angiogenesis and tumor growth, termed canstatin. Canstatin, a fragment of the alpha2 chain of type IV collagen, was produced as a recombinant molecule in Escherichia coli and 293 embryonic kidneys cells. Canstatin significantly inhibited human endothelial cell migration and murine endothelial cell tube formation. Additionally, canstatin potently inhibited 10% fetal bovine serum-stimulated endothelial cell proliferation and induced apoptosis, with no inhibition of proliferation or apoptosis observed on non-endothelial cells. Inhibition of endothelial proliferation was not concomitant with a change in extracellular signal-regulated kinase activation. We demonstrate that apoptosis induced by canstatin was associated with a down-regulation of the anti-apoptotic protein, FLIP. Canstatin also suppressed in vivo growth of large and small size tumors in two human xenograft mouse models with histology revealing decreased CD31-positive vasculature. Collectively, these results suggest that canstatin is a powerful therapeutic molecule for suppressing angiogenesis.

Angiogenesis Inhibitors↗
PubMed1999

[The determination of arterial pressure by the physician or the nurse: its relation to ambulatory pressure and left ventricular mass. The MAPA-Madrid Group. Monitorización Ambulatoria de la Presión Arterial (Ambulatory Monitoring of Arterial Pressure)].

BACKGROUND: In the present study we evaluated the influence of the observer's status--physician or nurse--on blood pressure levels and the relationship among clinic blood pressure measurement with ambulatory blood pressure and left ventricle mass. PATIENTS AND METHODS: Cross sectional study performed in seven primary care centers. Participating physicians and nurses were trained for blood pressure measurement prior to the study and subsequently retrained at 3 month intervals during the study. Patients included in the study were 122 subjects with mild to moderate hypertension who underwent the following study protocol: a) measurement of clinic blood pressure by physician and nurse, in an independent fashion, on 3 visits; b) clinic-epidemiologic questionnaire; c) conventional hematological and biochemical study; d) electrocardiogram; e) 24-hour ambulatory blood pressure monitoring, f) M-mode and Doppler echocardiography (only in 58 subjects). RESULTS: Nurse-measured blood pressure levels were higher than those determined by physicians (mean differences: 3.9 [6.7] mmHg in systolic blood pressure and 2.6 [5.4] mmHg in diastolic blood pressure). The blood pressure level differences between the two observers were higher in female patients and subjects with low educational level, independently of the observer's gender. Nurse-measured blood pressure was more closely related to ambulatory blood pressure and left ventricle mass than physician-measured blood pressure. CONCLUSIONS: Nurse-measured blood pressure levels are lower than those determined by physicians and more closely related to ambulatory blood pressure and left ventricle mass than physician-measured blood pressure. These data support that nurses, instead of doctors, should routinely measure blood pressure in primary care centers.

Adolescent↗
PubMed1999

Frequency and determinants of white coat hypertension in mild to moderate hypertension: a primary care-based study. Monitorización Ambulatoria de la Presión Arterial (MAPA)-Area 5 Working Group.

Most of the previous studies on white coat hypertension were performed in hypertension clinics or academic settings and included relatively small series of patients. Consequently, the prevalence of white coat hypertension in primary care settings and the clinical and epidemiologic characteristics of this subgroup of patients are not well known. We performed this study to estimate the frequency of white coat hypertension in a population of mildly to moderately hypertensive subjects attended in a primary care setting and to examine possible epidemiologic and clinical factors that may identify these patients. Patients included in the study underwent clinical interview, measurement of clinic blood pressure (BP) on three visits, determination of serum lipids, glucose, uric acid, and urinary albumin excretion, 24-h ambulatory BP monitoring, and M-mode and Doppler echocardiography. Patients were classified as white coat hypertensives if their daytime ambulatory BP were < 135/85 mm Hg. We studied 345 patients, 136 (39%) of whom were diagnosed with white coat hypertension. The frequency of white coat hypertension was inversely proportional to the severity of clinic BP values. The diagnosis of white coat hypertension was independently associated with female gender and low educational level. Left ventricular mass index and urinary albumin excretion were lower in the white-coat hypertensive group compared with the group with sustained hypertension. Our results show that a high proportion of patients with mild to moderate hypertension attended in a primary care setting have white coat hypertension. Some clinical characteristics may be helpful in the identification of this group of subjects. White coat hypertensives show less target-organ damage than sustained hypertensive patients.

Adult↗
PubMed1998

Sexually active adolescents and young adults: a high-risk group for Chlamydia trachomatis infection.

BACKGROUND: The importance of travel as a risk factor for Chlamydia trachomatis infection was evaluated among a series of young people consecutively tested. METHODS: We studied 130 sexually active young subjects, aged 14-25 years, all living in the Rome, Italy, urban area. Ninety-eight females and 32 males attended hospital-based clinics or were the partners of an infected female. About half of these subjects had traveled abroad either for pleasure or for work, mostly to Europe, but also to North America or to Asia, where they admitted to having had casual sex. We used two "gold standard" methods to diagnose infection with C. trachomatis: culture on McCoy cells grown in shell vial, and direct immunofluorescence with monoclonal antibodies. Subjects were considered infected when at least one test was positive. RESULTS: Thirty-nine of 130 (30%) subjects were asymptomatic, and 27/130 (20.8%) subjects were infected with Chlamydia trachomatis, of whom 6/25 (24%) asymptomatic females and 3/14 (21.4%) asymptomatic males were infected. Among teen-aged (ages 14-19) youngsters with more than one sex partner, international travel was an additional significant risk factor for C. trachomatis infection (p<.02; OR 20; 95% CI 1.47-40%). Urethritis/cystitis and vaginal pathology/discharge were the prevalent manifestations of illness among the females, while urethritis was the only clinical condition found in the males. CONCLUSION: In a series of young subjects, travel abroad, sex with more than one partner, and teen age, combined together, were significant risk factors for the acquisition of Chlamydia trachomatis genitourinary infection.

Adolescent↗