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Biomedical subjects

A Barrientos

Publications and source records attributed to A Barrientos.

At least 91 records · Page 5Linked to original sources
PubMed1995

Renal magnesium wasting with hypercalciuria, nephrocalcinosis and ocular disorders.

We report a case of congenital magnesium-losing kidney with associated hypercalciuria and ocular derangements consisting of myopia, bilateral macular colobomata and bilateral papillary dysversion and hypoplasia. Our patient provides further evidence of the existence of an oculorenal syndrome associating abnormalities in the renal handling of magnesium and calcium, and myopia and chorioretinal disease.

Adult↗
PubMed1994

Hemodialysis with acetate, DL-lactate and bicarbonate: a hemodynamic and gasometric study.

Using invasive techniques we have studied various hemodynamic and gasometric parameters in the course of hemodialysis (HD) with different buffers in an animal model. HD sessions of 180 minutes at zero ultrafiltration were carried out on three groups of eight uremic dogs each, under anesthesia and constant mechanical ventilation. The three groups differed only in the buffer used: acetate (Group AC), equal proportions of DL-lactate and acetate (Group AC+LA), and bicarbonate (Group BC). No hemodynamic changes were seen in Group BC. In the AC and AC+LA groups we observed on minute 1 a decrease of the mean blood pressure (MBP) and of the systemic vascular resistances (SVR). These parameters returned to baseline values within the first 30 minutes in Group AC+LA. In Group AC the SVR also returned to baseline values after the minute 30, but the MBP remained below baseline throughout the study period, together with cardiac index and left ventricular stroke work index decreases. Only in Group AC did we see a flattening of the ventricular function curves. Only in this Group was there a decrease of the arterial oxygen pressure (PaO2) with an associated increase of the alveolo-arterial and arterio-venous O2 differences. The O2 consumption was not modified in any of the groups. Acetate as a single buffer induces hemodynamic instability through peripheral vasodilation and reduction of myocardial contractility. The myocardial depression induced by acetate, in its turn, causes a reduction in PaO2. The mixed acetate+lactate buffer is hemodynamically better tolerated than acetate as single buffer, as it induces only vasodilation.

Acetates↗
PubMed1994

Multiple deletions of mtDNA in two brothers with sideroblastic anemia and mitochondrial myopathy and in their asymptomatic mother.

Two brothers presented with a clinical picture characterized by sideroblastic anemia, mild pancreatic insufficiency and progressive muscle weakness. The presence of an associated permanent basal lactic acidemia raised the suspicion of a mitochondrial disease. A muscle biopsy performed in both siblings proved the presence of a significant number of ragged-red fibers, and respiratory chain enzymatic determinations demonstrated a reduced activity of complexes I, III and IV. Mitochondrial DNA studies disclosed the presence of multiple deletions both in skeletal muscle and, to a lesser extent, in leukocytes. Similar, but not identical deletions were also present in the leukocytes and muscle from their mother. Deletions were flanked by short direct repeats. We conclude that such patients suffer from a familial form of mitochondrial disease clinically resembling Pearson's syndrome, with a probably autosomal dominant inheritance.

Adult↗
PubMed1994

Mutations in the type IV collagen alpha 3 (COL4A3) gene in autosomal recessive Alport syndrome.

A group of 22 unrelated patients with sporadic or non-X-linked Alport syndrome were screened for mutations in the non-collagenous domain of the type IV collagen alpha 3 (COL4A3) chain gene. The five 3'-exons of this gene, located on chromosome 2qter, were tested by single strand conformation polymorphism analysis and direct sequencing. One patient was heterozygous and another homozygous (Mochizuki et al., Nature Genetics, in press) for a deletion of five nucleotides. A third patient appeared to be a compound heterozygote for two different nonsense mutations. In two patients and the father of a deceased patient we found a heterozygous substitution of an evolutionary conserved leucine by proline. However, segregation data of the mutation and a COL4A3/COL4A4 CA-repeat marker in their families argued against a causative role of the missense mutation. Even drastic changes of strongly conserved amino acids, as in the Leu36Pro case, may not be significant. Autosomal recessive inheritance due to pathogenic COL4A3 mutations accounts for at least 13% of Alport syndrome cases in this sample. It is concluded that COL4A3 is a major gene in the genetically and clinically heterogeneous Alport syndrome.

Base Sequence↗
PubMed1994

Alveolar hemorrhage associated with antineutrophil cytoplasmic antibodies in rheumatoid arthritis.

A 65-year-old woman with previously known rheumatoid arthritis and chronic renal failure of possible glomerular origin was admitted to the hospital because of hemoptysis and respiratory insufficiency. Antineutrophil cytoplasmic antibodies (ANCAs) with antimyeloperoxidase activity were detected in her serum. The lung biopsy specimen evidenced alveolar hemorrhage. Under immunosuppressive therapy with steroids and cyclophosphamide, the patient's condition improved both clinically and radiologically, and the ANCA became negative after 6 months' therapy.

Aged↗
PubMed1993

Iron deficiency anemia after successful renal transplantation.

In patients with chronic renal failure, renal transplantation improves anemia and the production of erythropoietin. In patients undergoing hemodialysis the administration of recombinant human erythropoietin improves anemia with a decrease in bodily iron stores. Therefore, one would expect a similar decrease after kidney transplantation. We followed the ferric parameters to determine the incidence of iron deficiency anemia in 24 consecutive renal transplant patients for an interval long enough to achieve steady state values of hemoglobin (5.1 +/- 0.8 months). Hematological parameters and serum levels of iron, ferritin and erythropoietin were measured. The patients were divided into 2 groups according to the decrease in serum ferritin: group 1--16 with a decrease in respect to basal values (114 +/- 56 ng./ml.) and group 2--those without modifications (720 +/- 320 ng./ml.). Except for the similar values, group 1 showed greater improvement in anemia (red blood cells 4.3 x 10(6) +/- 1.1 x 10(6) versus 3.7 x 10(6) +/- 1.5 x 10(6)/ml., p < 0.01) and hematocrit index (38.5 +/- 5.2 versus 33.0 +/- 5.1%, p < 0.05). Four patients had microcythemia (mean corpuscular volume 76.6 +/- 1.4 fluid) with lower hemoglobin values than the other patients in group 1 (10.77 +/- 0.42 versus 12.79 +/- 0.42 gm./dl., p < 0.05). Among the 16 patients in group 1, 7 of 8 whose basal serum ferritin was less than 150 ng./ml. achieved ferritin levels of less than 30 ng./ml. In conclusion, our data support that renal transplantation produces a rapid decrease in iron stores and in some cases induces iron deficiency anemia. This fact should be evaluated and treated properly.

Adult↗
PubMed1993

Hypomagnesemic hypocalcemia in chronic renal failure.

Hypomagnesemic hypocalcemia in chronic renal disease is a rare finding. Controversy remains regarding the role of decreased magnesium in producing impaired parathyroid hormone (PTH) secretion versus target organ unresponsiveness to PTH. We describe six patients with severe chronic renal disease in whom hypocalcemia and hypomagnesemia were detected. Five patients had chronic interstitial nephropathy; all of them showed renal magnesium wasting. One patient had chronic glomerulonephritis and a malabsorption syndrome and showed a low rate of urinary excretion of magnesium. The administration of magnesium increased calcium levels in all patients. We have found elevated PTH levels in absolute terms, which, however, were inappropriate to correct hypocalcemia; the PTH levels increased in three patients and not in the other three after magnesium replacement. We conclude that in patients with tubulointerstitial nephropathies, chronic renal losses of magnesium can produce hypomagnesemic hypocalcemia.

Adult↗