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Biomedical subjects

L Carreras

Publications and source records attributed to L Carreras.

At least 19 recordsLinked to original sources
PubMed2000

Evaluation of red blood cell aggregation in diabetes by computerized image analysis.

Red blood cell (RBC) aggregation has been widely studied and its importance is well established in the rheology of microcirculation. RBC aggregation is a major factor responsible for the flow properties of blood. Increased RBC aggregation has been observed in several pathological states. Therefore, the measurement of erythrocyte aggregation is rheologically important for quantifying flow abnormality in pathological conditions. Normal RBC under low flow or at rest form rouleaux aggregates, while abnormal RBC aggregation may lead to the formation of irregular aggregate structures, which may be induced by cell-associated factors (reduced membrane sialic acid levels) but also by extracellular factors. The main objective of the present investigation was to study RBC aggregate morphology in diabetic patients, using direct microscopic observation and numerical processing of recorded digitized images. Blood samples were obtained from 20 diabetic patients and from 15 normal control subjects. The aggregate morphology was quantified by the so-called Aggregate Shape Parameter (ASP) defined as the ratio of the aggregate projected area to its square perimeter. ASP appeared significantly higher (p < 10(-5)) in diabetic patients (0.65 +/- 0.18) than in normal controls (0.28 +/- 0.15). This rheo-optical method based on the theoretical model for rouleaux aggregates provides a useful reference for measuring deviations of RBC aggregate morphology. Increased aggregation of RBC resulting from a decreased sialylation of glycophorins may be an important factor in the development of vascular diseases and in the microcirculation impairment.

Adult↗
PubMed1995

[Therapeutic immunoadsorption in Goodpasture disease].

The extraction of circulating antiglomerular basement membrane (GBM) antibodies by plasmapheresis (PP) has allowed the prognosis of Goodpasture's disease to markedly improve. Immunoabsorption (IA) may improve the results of PP upon allowing more effective immunoglobulin extraction. Two patients with Goodpasture disease were treated with IA. A rapid decrease was observed in the serum levels of anti GBM antibodies and improvement in respiratory failure. In one of the patients this regimen was administered following the observation of a lack of clinical response of pulmonary hemorrhage in three PP sessions (9 liters of treated plasma). In this patient, the IA processed 39 liters of plasma and the method was found to be equally effective on reinstatement (29 liters) on the occasion of a relapse in the pulmonary symptoms presented at three weeks after the first treatment. Both cases showed renal involvement. In one case this was incipient and the treatment was associated with non progression of the kidney disease, normalization of the urine sediment and preservation of renal function. In the second case treatment was initiated at an advanced disease state with no changes in dialysis needs. Immunoadsorption has shown to be effective in the treatment of pulmonary hemorrhage in Goodpasture's disease. Onset of treatment at an early stage of the kidney disease may avoid progression to renal failure.

Adult↗
PubMed1995

Interstitial nephritis in sarcoidosis: simultaneous multiorgan involvement.

Two cases of sarcoidosis with interstitial nephritis (lymphocytic and granulomatous) are described. In contrast to the majority of reported cases, patients simultaneously exhibited renal failure and multiple extrarenal manifestations, including bone marrow granulomas. Pretreatment gallium-67 gamma scan of the kidneys produced negative results. Patients were treated with steroids. Treatment resulted in a normal renal function after 1 year in the patient with lymphocytic interstitial nephritis. Renal function improved in the patient with granulomatous interstitial nephritis, and a second renal biopsy performed 13 months after diagnosis revealed granuloma disappearance and residual interstitial fibrosis. These cases provide evidence that interstitial nephritis in sarcoidosis may appear simultaneously with multiorgan involvement. The absence of gallium-67 renal intake does not guarantee that the disease is not active in the kidneys.

Female↗
PubMed1992

[Renal vasculitis without hematuria in senile patients].

Systemic vasculitis is a disease whose prognosis has improved considerably with steroid and immunosuppressive treatment, which points up the importance of early diagnosis. In elderly, diagnosis is made more difficult because the frequent onset in the form of a febrile syndrome with non-specific disturbances in general condition. In these patients it is not uncommon that a kidney involvement is what leads to diagnosis of the disease. Hematuria is almost a constant in vasculitis nephropathy. In their absence, acute renal failure in elderly is usually attributed to hemodynamic causes and the frequent presence of iatrogenic tubular factors. This is a report on the case of three elderly patients who presented a febrile syndrome with asthenia, anorexia and weight loss. The three cases progressed to acute renal failure with no disorders in urinary sediment. In two cases was a history of administration of gentamycin, indomethacin and iodated contrast. The clinical diagnosis was toxic and ischemic tubulopathy and, when dialysis became necessary, a renal biopsy was done which showed granulomatous vasculitis, intersticial nephritis and in two cases, necrotizing glomerulitis and crescent formation. Treatment with steroids and cyclophosphamide was started which improved general condition and renal function in one case. Early renal biopsy is advisable in senile patients with non specific systemic symptoms and progressive acute renal failure of unclear origin, even when hematuria is lacking. In this setting, the appearance of underdiagnosed renal vasculitis is possible, and consequent immunosuppressive treatment is a factor for consideration.

Acute Kidney Injury↗
PubMed1988

Apparent recurrence of hemolytic uremic syndrome in azathioprine-treated allograft recipients.

The present study describes 3 adult patients with hemolytic uremic syndrome (HUS) leading to chronic renal failure. Following renal transplantation, the 3 patients developed microangiopathic hemolytic anemia associated with acute rejection crises and graft failure. In 2 patients the renal histology of the transplanted kidney was consistent with HUS. It is concluded that, in adult patients, HUS may recur after renal transplantation and contribute to renal graft failure.

Adult↗
PubMed1986

Rectification of the remnants of the leaflets--a new surgical technique to avoid periprosthetic leaks in aortic valve replacement.

During the last 12 years, we have used a modified suture technique for aortic valve replacement in 450 patients in order to avoid periprosthetic leaks. There were 420 survivors, and reoperation for periprosthetic leaks was necessary in no instance. The "secret" of our technique consists of the uniform distribution of the tensile forces among all sutures, eliminating uneven stresses that favors tearing of the tissues or rupture of the stitches.

Adolescent↗
PubMed1985

Humoral and cellular immunological abnormalities in hypertensive patients.

A high frequency of immunological disturbances were recorded in 19 mild and 23 malignant hypertensive patients. IgG levels were raised in patients who survived a malignant phase of hypertension. We also found increased frequency of autoantibodies (26% vs. 9% in controls), increased T-lymphocyte reactivity against arterial-wall antigens (p = 0.001), a significant frequency of low responders to PHA (p = 0.003), and a statistically significant correlation (p = 0.031) between the presence of autoantibodies and T-cell hyper-reactivity against arterial antigens in mild hypertensive patients. We suggest that these abnormalities might be relevant in the pathogenesis of some hypertensive conditions. Autoantibody production is likely to be correlated with a predisposition to hypertension through some autoimmune mechanisms.

Adult↗