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J Font

Publications and source records attributed to J Font.

At least 253 records · Page 14Linked to original sources
PubMed1987

Isolation, molecular and biological properties of a lectin from rice embryo: relationship with wheat germ agglutinin properties.

Rice lectin (Oryza sativa, var. Balilla 28) was purified from defatted embryos by aqueous acid extraction at pH 1.3 followed by ammonium sulfate precipitation between 2 and 4 M, affinity chromatography on agarose-p-aminophenyl-beta-D-N-acetylglucosamine, and gel filtration on AcA 54. The homogeneity of the lectin was checked by polyacrylamide gel electrophoresis, gel filtration, and immunodiffusion. The amino acid analysis revealed a high half-cystine content (9%) and a low aromatic and hydrophobic amino acid content. The lectin contained neither neutral carbohydrates nor amino sugars. The isoelectric point was estimated to be 8.1. The molecular weight of rice lectin was estimated to be 38,000. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis under reducing conditions showed two polypeptides with Mr 19,000 and 15,000. The circular dichroism spectrum of rice lectin in far ultraviolet was characterized by a positive maximum at 228 nm and a negative band at 203 nm suggesting the presence of a beta-pleated sheet and the absence of alpha-helix. Rice lectin had no human blood group specificity and agglutinated rabbit erythrocytes more efficiently than erythrocytes from other animal species. Furthermore, agglutination was enhanced by trypsin treatment of erythrocytes. The erythroagglutinating activity was very high since the minimal concentration needed to agglutinate erythrocytes was 0.05 micrograms/ml. Although [methyl-3H]thymidine incorporation was stimulated in human lymphocytes, rice lectin could not be considered as a mitogenic lectin since it stimulated neither blast transformation nor lymphocyte proliferation. The saccharide specificity of rice lectin was related to N-acetylglucosamine and its oligomers: N,N',N"-triacetylchitotriose was the most powerful inhibitor. Furthermore, the N-acetylneuraminic acid was not a specific rice determinant. Finally, the double immunodiffusion method revealed a cross-reactivity between rice lectin and wheat germ agglutinin, indicating that these lectins were closely antigenically related. The analogies and differences between biological and immunological properties of rice lectin and wheat germ agglutinin are discussed and the possibility of their evolution from a common ancestor is put forward.

Amino Acids↗
PubMed1987

Silent renal disease in systemic lupus erythematosus.

Several recent studies have focused on the discrepancy between lupus nephropathy and clinical renal involvement and, consequently, question the relevance of renal biopsy in these patients. We analyze the clinical characteristics, histological renal findings and subsequent course of patients with silent renal disease. Renal biopsy was performed in 15 patients with systemic lupus erythematosus (SLE) who had no clinical signs of renal involvement (no urinary sediment abnormalities, absence of proteinuria and serum creatinine less than 1.3 mg/dl). All biopsies were classified according to a modified classification proposed by the WHO. Six cases (40%) showed no histological or immunofluorescence changes (type I), 7 (47%) had mesangial nephropathy (3 type IIa and 4 type IIb) and 2 (13%) had focal proliferative glomerulonephritis (type III). None of the patients had previous evidence of neurological abnormalities. Patients with type I only had arthritis, skin lesions and Raynaud's phenomenon. By contrast, 7 patients with histological renal involvement had serositis or hemolytic anemia. All cases with silent nephropathy were treated with steroids and showed a benign clinical course with stable renal function and absence of urinary abnormalities during follow-up. We concluded that in the absence of clinical renal abnormalities, renal involvement is not uncommon in SLE. We believe that a renal biopsy should be performed mainly in those SLE patients presenting with clinical manifestations other than arthritis or cutaneous lesions since this policy may allow detection of significant silent renal injury.

Adolescent↗