RESUMEN
BACKGROUND: This study was designed to determine the magnitude and frequency of measurement errors with infrared tympanic thermometers in the clinical setting. METHODS: In a convenience sample of 137 adult inpatients, we compared body temperatures measured by a Diatek 9000 Infrared Aural Thermometer and an IVAC 2090 CoreCheck Tympanic Thermometer between themselves, in right versus left ears, and against concurrently measured oral temperatures using both an electronic thermoprobe and conventional glass mercury thermometer. RESULTS: There was a significant between-brand difference of 0.6 degrees C (IVAC Asunto(s)
Electrónica/instrumentación
, Mercurio
, Mucosa Bucal
, Termografía/instrumentación
, Termómetros/normas
, Membrana Timpánica
, Adolescente
, Adulto
, Anciano
, Anciano de 80 o más Años
, Análisis de Varianza
, Sesgo
, Cerumen
, Femenino
, Humanos
, Masculino
, Persona de Mediana Edad
, Reproducibilidad de los Resultados
RESUMEN
The development of IgA nephropathy in first degree relatives is a well-described, yet relatively uncommon, occurrence. The association of a C4 isotype deficiency or partial deficiency of another complement protein has been previously documented for patients with IgA nephropathy. The present report describes a family in which two siblings and their father had biopsy-confirmed IgA nephropathy; both siblings were deficient for the C4B isotype. In addition, one of the biopsied siblings and a third sibling with microscopic hematuria but no renal biopsy apparently had a partial deficiency of the complement regulatory protein, I. The findings in this family may be compatible with the hypothesis that a C4 isotype deficiency and/or a partial deficiency of an individual complement protein allows clinical expression of IgA nephropathy in an individual with a genetic susceptibility for the disease.
Asunto(s)
Complemento C4b/deficiencia , Glomerulonefritis por IGA/inmunología , Adolescente , Adulto , Afibrinogenemia/complicaciones , Afibrinogenemia/genética , Complemento C4a/análisis , Complemento C4a/genética , Electroforesis en Gel de Agar , Femenino , Glomerulonefritis por IGA/complicaciones , Glomerulonefritis por IGA/genética , Haplotipos/genética , Humanos , Masculino , Persona de Mediana Edad , Linaje , FenotipoRESUMEN
Certain alleles for the complement proteins, C4 and Bf, have been shown to be markers for insulin-dependent diabetes mellitus (IDDM) in samples of different racial and geographic composition. However, the same markers are not demonstrable in each group studied. Phenotyping for the complement alleles, C4 and Bf was performed on 168 Caucasian and 49 Black patients with IDDM. All of the patients were followed in Memphis, Tennessee and had onset of disease prior to age 18. The Bf*F1 allelic frequency was significantly increased for the Caucasian patients as compared to 93 healthy Caucasian controls (0.063 vs. 0.016) and for the Black IDDM patients as compared to 43 healthy Black controls (0.102 vs. 0.035). C4 phenotype frequencies showed a significant increase of the C4AQ0 (rr = 2.13) and C4A4 (rr = 2.91) phenotypes for the Caucasian IDDM patients as compared to controls, but the frequency of homozygous null C4A was not significantly increased. In addition significant negative associations of IDDM with C4A3 and C4A6 phenotypes and no association with any C4B phenotype were observed in our Caucasian patient population. Our data for Mild-South Blacks with IDDM suggest a similar positive association of IDDM with the BfF1 phenotype (rr = 3.4). However, there was no evidence among Black IDDM patients of the C4AQ0 and C4A4 associations observed in the Caucasian sample. The data support a possible association of IDDM with the C4A2 (rr = 5.86) and C4B2 (rr = 5.26) phenotypes. The hypothesis that racial admixture may account for the higher frequency of IDDM in US Blacks as compared with African Blacks has been forwarded by others.(ABSTRACT TRUNCATED AT 250 WORDS)
Asunto(s)
Complemento C4/genética , Factor B del Complemento/genética , Diabetes Mellitus Tipo 1/inmunología , Precursores Enzimáticos/genética , Alelos , Población Negra/genética , Niño , Diabetes Mellitus Tipo 1/genética , Femenino , Frecuencia de los Genes , Marcadores Genéticos , Humanos , Masculino , Fenotipo , Población Blanca/genéticaRESUMEN
Phenotype frequencies for the complement proteins Bf (factor B), C4A and C4B were performed in a sample of 49 Caucasian patients with psoriasis followed in Memphis, Tennessee. The genes for these proteins are located in the major histocompatibility complex between the HLA-B and HLA-DR loci. Bf phenotype frequency did not differ significantly for the patients as compared to regional controls. The C4*A6 allele was present in 26.6% of the patients as compared to 5.4% of the controls, p less than 0.001, relative risk = 4.93. The C4*A6 allele is known to be in linkage disequilibrium with the HLA B17 allele and produces a functionally defective gene product. The role, if any, of C4*A6 in the pathogenesis of psoriasis is uncertain.
Asunto(s)
Complemento C4/genética , Factor B del Complemento/genética , Precursores Enzimáticos/genética , Psoriasis/genética , Electroforesis/métodos , Humanos , FenotipoRESUMEN
Phenotype frequencies for the complement proteins C4A, C4B, Bf (factor B) and C3 were performed for 49 Caucasian patients with psoriasis. The C4*A6 allele was present in 26.6% of the patients as compared to 5.4% of healthy regional Caucasian controls, p less than 0.001, relative risk = 6.28. The C4*A6 allele is known to be in linkage disequilibrium with the HLA B17 allele and to produce a non-functional gene product when it occurs with the B17 allele. HLA B17 is known to be associated with psoriasis in many Caucasian populations. Additional findings in the present study were a significant reduction in the C4B*2 allele frequency, a non-significant increase in the Bf*F allele frequency and no difference for Bf or C3 phenotype frequencies in the patients with psoriasis as compared to the controls.
Asunto(s)
Proteínas del Sistema Complemento/genética , Psoriasis/genética , Complemento C3/genética , Complemento C4/genética , Complemento C4a/genética , Complemento C4b/genética , Factor B del Complemento/genética , Frecuencia de los Genes , Humanos , Fenotipo , Población BlancaRESUMEN
Activation of alternative complement pathway is presumed to be important pathogenically in IgA nephropathy since renal biopsies usually exhibit glomerular deposition of C3 and P (properdin). Surprisingly, little is known about plasma complement activation in this disease, and the plasma C3 and C4 concentrations are usually normal or increased. We quantitated C3 activation in 202 plasmas from 81 patients with IgA nephropathy using a sensitive new assay that detects a neoantigen [iC3b-C3d neoantigen) which appears when C3b is inactivated to iC3b, C3dg, or C3d. This assay accurately quantitates small amounts of in vivo C3 activation. The concentration of iC3b-C3d neoantigen in plasma was significantly increased, indicating C3 activation in 37% of the pediatric and 57% of the adult plasmas assayed. When data from serial determinations in the patients were analyzed, 75% of the adult and 57% of the pediatric patients had C3 activation on at least one occasion. Classical pathway activation, quantitated by C4 activation was found in 20% of the adult and 5% of the pediatric plasmas. No association was found between elevated iC3b-C3d neoantigen concentration and history of macroscopic hematuria, chronic renal insufficiency or degree of proteinuria. These studies show that complement activation can frequently be detected in the plasma of IgA nephropathy patients. However, the pathophysiologic significance of this complement activation remains to be determined.