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R García-Torres

Publications and source records attributed to R García-Torres.

18 recordsLinked to original sources
PubMed2000

Morphology of vascular, renal, and heart lesions in the antiphospholipid syndrome: relationship to pathogenesis.

A growing body of evidence suggests that aPL are not only serological markers of the antiphospholipid syndrome (APS), but may also directly contribute to the development of thrombosis and other manifestations, including the APS vasculopathy. The latter has been documented in leptmeninges, lung, skin, myocardium, peripheral arteries, and kidney. Renal lesions, a common feature of primary antiphospholipid syndrome (PAPS), include occlusion of principal renal arteries or their main branches, TMA, cortical ischemia, and renal vein thrombosis. Within the cardiac manifestations associated with aPL, valvular involvement is the most common. Histologic findings in valve specimens are consistent with a noninflammatory lesion characterized by intravalvular capillary thrombosis, laminar or verrucous superficial thrombosis, vascular proliferation, fibrosis, and calcification. Even though there is general consensus that endothelial damage triggers the chain of events that results in valve thickening, fusion, rigidity, and ultimately functional abnormalities, we believe that more experimental work remains to be done on the initial valve insult in APS.

Antibodies, Antiphospholipid↗
PubMed1998

Role of NO in cyclosporin nephrotoxicity: effects of chronic NO inhibition and NO synthases gene expression.

The role of nitric oxide (NO) during cyclosporin renal vasoconstriction was evaluated by glomerular hemodynamic and histological changes produced by chronic NO synthesis inhibition and neuronal (nNOS), inducible (iNOS), and endothelial (eNOS) NO syntheses mRNA expression in renal cortex and medulla. Uninephrectomized rats treated during 7 days with vehicle (Veh), cyclosporin A (CsA) 30 mg/kg, CsA + nitro-L-arginine methyl ester (L-NAME), and Veh + L-NAME (10 mg/dl) in the drinking water were studied. Increase in arterial pressure and afferent and efferent resistances, as well as decrease in glomerular plasma flow, ultrafiltration coefficient, and single-nephron glomerular filtration rate were significantly greater with CsA + L-NAME than with CsA alone. The increase in afferent resistance was higher with CsA + L-NAME than with Veh + L-NAME. In addition, glomerular thrombosis, proximal tubular vacuolization, and arteriolar thickening were more prominent. In renal cortex, eNOS mRNA expression exhibited a 2.7-fold increase in CsA, whereas, in medulla, nNOS and iNOs expression were lower in CsA than in Veh, while eNOS tended to increase. Our results support the hypothesis that NO synthesis is enhanced at cortical level during CsA nephrotoxicity, counterbalancing predominantly preglomerular vasoconstriction. Higher NO production could be the result of increased eNOS mRNA expression.

Animals↗
PubMed1997

Absence of ANCA in Mexican patients with Takayasu's arteritis.

Antineutrophil cytoplasmic autoantibodies (ANCA) were sought in 43 sera from 39 Mexican patients with typical Takayasu's arteritis (TA), (5 with active and 34 with inactive disease), and in a comparative group comprising 50 sera. Results were negative in all cases. This suggests that ANCA are not a serologic feature in TA per se, even during its active stage. ANCA positivity in TA, when present, may be a non-related phenomenon and probably identifies a subset of patients with atypical forms of TA or a polyangiitis overlap syndrome.

Adult↗
PubMed1996

Valvular heart disease in primary antiphospholipid syndrome (PAPS): clinical and morphological findings.

PURPOSE: To describe clinically and pathologically the valvular lesion of the primary antiphospholipid syndrome (PAPS). PATIENTS AND METHODS: We studied six patients with PAPS and valvulopathy. Four of them died and had autopsy and two had valvular replacement. The study comprised 18 heart valves, 16 from autopsy and two, one mitral and one aortic, resected at surgery. RESULTS: Murmurs and echocardiographic findings kept correlation with gross pathology. Abnormalities were found in one or more valves in all patients including two of five aortic, two of five mitral, one of four pulmonary and two of four tricuspid. Co-existence of new and old lesions was observed. Pathologic findings included intravalvular thrombosis with focal necrosis, and hemorrhage, vascular proliferation, mild histiocytic/fibroblastic infiltration, laminated and verrucous fibrin deposits, laminated and/or nodular fibrosis, and focal calcification. CONCLUSION: The PAPS valvular lesion consists mainly of superficial or intravalvular fibrin deposits and its subsequent organization: vascular proliferation, fibroblast influx, fibrosis and calcification. This results in valve thickening, fusion and rigidity leading to functional abnormalities. Inflammation is not a prominent feature of this lesion.

Adult↗
PubMed1994

Role of nitric oxide in renal hemodynamic abnormalities of cyclosporin nephrotoxicity.

To evaluate the participation of nitric oxide (NO) in chronic cyclosporin A (CsA) nephrotoxicity, the glomerular hemodynamic response to NO inhibition with N-nitro-L-arginine-methyl-ester (NAME) and stimulation of NO production with L-arginine was studied in uninephrectomized rats. Chronic CsA administration produced renal vasoconstriction, characterized by increased afferent (AR) and efferent (ER) resistances, decrease of glomerular plasma flow (QA) and ultrafiltration coefficient (Kf) that resulted in a 53% fall of single-nephron glomerular filtration rate (SNGFR). NAME infusion in vehicle group (V) elevated mean arterial pressure (MAP), AR and ER, reduced qA and Kf, and increased glomerular capillary pressure (PGC), resulting in a 28.9% fall of SNGFR. In the CsA group, NAME also increased MAP, but renal vasoconstriction was more intense; a greater rise of AR lowered PGC (P < 0.05 vs. V) further decreasing SNGFR by 38.9%. In control rats, L-arginine infusion induced a vasodilatory response of AR and ER, and elevation of QA and Kf, which resulted in a 72.6% increase in SNGFR. In the CsA group, greater vasodilation was observed and SNGFR rose by 114.9%. NO2-/NO3- urinary excretion was similar in CsA and V groups, and it was not modified by NAME in either group, but it increased five- to sixfold during L-arginine infusion in both groups. In conclusion, in CsA nephrotoxicity NO production seems to be normal and the ability of the renal endothelium to produce NO is maintained. Therefore renal vasoconstriction associated with CsA is not mediated by NO deficiency, although NO appears to attenuate it.

Animals↗
PubMed1993

Alport-leiomyomatosis syndrome: an update.

Alport-leiomyomatosis syndrome is a polygenic syndrome with a dominant X-linked inheritance pattern resulting from a large deletion in the 5' end of the COL4A5 gene coding for the type IV collagen alpha 5 chains. Hypothetically, the deletion extends beyond the 5' end and probably includes a second contiguous gene responsible for leiomyomatosis (the DL gene) and even a third one coding for congenital cataract (the CCT gene).

Adolescent↗
PubMed1993

[Alport's syndrome: new findings].

The Alport's syndrome is a disease characterized by a symptomatic triad: nephropathy, hypoacusia and ocular alterations. This syndrome is genetically heterogeneous and results from numerous mutations in COL4A5 gene, whose locus resides on the long arm of the X chromosome (Xq22). This gene codifies for IV collagen alpha 5 chain, which is a fundamental constituent of the glomerular, lens and Corti's organ basal membranes. Present knowledge on molecular genetics and the characterization of the different mutations that affect the Alport's gene will lead to classification of this syndrome in subtypes, according to those mutations, and to its phenotypic expressions; in addition, some syndromes, phenotypically similar, will probably have to be distinguished from Alport's disease, in a future, if a genetic alteration is found in genes other than COL4A5.

Collagen↗
PubMed1992

Mechanisms involved in the progression to glomerular sclerosis induced by systemic hypertension during mild puromycin aminonucleoside nephrosis.

To evaluate the contribution of systemic hypertension in the progression of nephropathies to glomerular sclerosis, a mild form of puromycin aminonucleoside (PAN) nephrosis was associated with Goldblatt hypertension and studied after 18 weeks. We studied four groups: Group I, controls; Group II, Goldblatt hypertension; Group III, PAN nephrosis; and Group IV, both conditions. Systolic blood pressure, 24-h proteinuria, serum cholesterol, triglycerides, glomerular hemodynamics, and histological studies were compared among the groups. Rats in groups II and IV developed systemic hypertension, but only group IV rats showed persistent proteinuria. No alterations in lipid metabolism were present in any of the groups. The most striking findings in the micropuncture studies were a significant increase of glomerular capillary pressure in group IV rats (63.15 +/- 1.34 mm Hg) as compared to controls (48.74 +/- 0.97 mm Hg) and to groups II and III (55.31 +/- 2.11 and 48.17 +/- 1.23 mm Hg, respectively), and a marked fall in Kf in groups III and IV. Only group IV showed significant histological alterations such as glomerular sclerosis, interstitial damage, and increased glomerular area. These results suggest that, in the presence of an underlying nephropathy, a greater fraction of systemic pressure is transmitted to the glomerular capillaries when systemic hypertension is present; the resulting elevation in glomerular pressure and proteinuria seems to be responsible for the progression to glomerular sclerosis.

Animals↗
PubMed1992

[Drash's syndrome and its variants. A report of 3 cases].

Three cases of Drash syndrome (DS) are presented. Two of them were 2 years old, the third one a newborn. Two are autopsy cases, one of the patients is alive. All three of them had nephrotic syndrome and renal failure, with mesangial sclerosis. All three had ambiguous genitalia, abdominal testes with variable degrees of dysgenesis and bilateral gonadoblastoma. Two cases had 46XY karyotype, in one case it was not performed. Two patients had nephroblastoma, one of them after several months of nephropathy, in the other it was the cause of consultation. The patient without nephroblastoma died at the age of 26 days with renal failure. We think that the original triad of DS: nephroblastoma, pseudohermaphroditism and nephropathy should be more precisely described and expanded to include related alterations in each one of its 3 elements: nephroblastomatosis, hamartomas, probably mesoblastic nephroma and pyelocaliceal malformations in addition to Wilms' tumor, variable disorders of sexual differentiation, gonadal dysgenesis and neoplasia, in addition to pseudohermaphroditism and superficial cortical renal dystrophy and increased reniculi, in addition to mesangial sclerosis. The various clinical forms of the syndrome are combinations of the triad in which a component can be missing and/or other related malformations be present. Chromosome anomalies are possibly responsible for this phenomena. Splitting into separate syndromes should not be done until the chromosome alterations and the regions and genes involved are identified.

Child, Preschool↗
PubMedDate not supplied

[Histological changes in renal transplants].

The main histological alterations observed in renal transplants, based on a short review of the medical literature and the Pathology Department of the General Hospital (National Medical Center. Mexican Institute of the Social Security) own experience, are reported.

Acute Kidney Injury↗
PubMedDate not supplied

[Nephropathology caused by congenital syphilis. Report of a case].

A case of congenital syphilis is reported. It deals with a three-month-old girl suffering from a nephropathy clinically characterized by edema, hematuria, severe proteinuria and slight renal insufficiency. On light an delectron microscopy, a mesangial proliferative and focal extracapillary proliferative glomerulonephritis with abundant intermembranoepithelial deposits was observed.

Diagnosis, Differential↗