RESUMEN
BACKGROUND: Genetic disposition and androgen dependence are important characteristics of the common patterned loss of scalp hair known as androgenetic alopecia (AGA). The genetic factors contributing to AGA are currently unknown. The human hairless gene (HR) has recently been cloned and mutations have been reported in families with autosomal recessive universal congenital alopecia and papular atrichia. The main feature of these disorders is persistent complete absence of hair at or shortly after birth. This suggests that HR is essential and specific for the development of hair. OBJECTIVES: To test the hypothesis that HR may be involved in AGA. METHODS: We systematically screened HR for genetic variability by means of single-strand conformation analysis (SSCA) in 46 unrelated men with AGA. To test for an involvement of HR in the development of AGA, seven common variants were genotyped in 61 families with 93 affected offspring. The results were analysed with the transmission/disequilibrium test (TDT). RESULTS: SSCA showed 15 single nucleotide substitutions: eight missense mutations, four silent mutations and three mutations in exon-flanking intronic sequences. TDT results showed a marginally significant association between AGA and variants 3379-29G/T (P = 0.024) and 2611-68C/T (P = 0.047). These results, however, did not remain significant after applying the conservative Bonferroni correction for multiple testing. CONCLUSIONS: Our results do not provide evidence for a strong involvement of HR in the development of AGA, although a minor role cannot be fully excluded.
Asunto(s)
Alopecia/genética , Mutación , Proteínas/genética , Adulto , Alelos , Cartilla de ADN/genética , Variación Genética , Genotipo , Humanos , Masculino , Mutación Missense , Reacción en Cadena de la Polimerasa/métodos , Polimorfismo Conformacional Retorcido-Simple , Factores de TranscripciónAsunto(s)
Alopecia/genética , Mutación Missense/genética , Mutación Puntual/genética , Polimorfismo Genético/genética , Proteínas/genética , Factores de Transcripción , Adolescente , Adulto , Secuencia de Bases , Análisis Mutacional de ADN , Etnicidad/genética , Exones/genética , Femenino , Frecuencia de los Genes/genética , Genotipo , Haplotipos/genética , Humanos , Masculino , Persona de Mediana Edad , Linaje , Proteínas/química , Grupos Raciales/genética , Dedos de Zinc/genéticaRESUMEN
About 24 intrinsic neurosecretory neurons within the pericardial organs (POs) of the crab Carcinus maenas produce a novel crustacean hyperglycaemic hormone (CHH)-like peptide (PO-CHH) and two CHH-precursor-related peptides (PO-CPRP I and II) as identified immunochemically and by peptide chemistry. Edman sequencing and MS revealed PO-CHH as a 73 amino acid peptide (8630 Da) with a free C-terminus. PO-CHH and sinus gland CHH (SG-CHH) share an identical N-terminal sequence, positions 1-40, but the remaining sequence, positions 41-73 or 41-72, differs considerably. PO-CHH may have different precursors, as cDNA cloning of PO-derived mRNAs has revealed several similar forms, one exactly encoding the peptide. All PO-CHH cDNAs contain a nucleotide stretch coding for the SG-CHH(41-76) sequence in the 3'-untranslated region (UTR). Cloning of crab testis genomic DNA revealed at least four CHH genes, the structure of which suggest that PO-CHH and SG-CHH arise by alternative splicing of precursors and possibly post-transcriptional modification of PO-CHH. The genes encode four exons, separated by three variable introns, encoding part of a signal peptide (exon I), the remaining signal peptide residues, a CPRP, the PO-CHH(1-40)/SG-CHH(1-40) sequences (exon II), the remaining PO-CHH residues (exon III) and the remaining SG-CHH residues and a 3'-UTR (exon IV). Precursor and gene structures are more closely related to those encoding related insect ion-transport peptides than to penaeid shrimp CHH genes. PO-CHH neither exhibits hyperglycaemic activity in vivo, nor does it inhibit Y-organ ecdysteroid synthesis in vitro. From the morphology of the neurons it seems likely that novel functions remain to be discovered.
Asunto(s)
Empalme Alternativo , Hormonas de Invertebrados/aislamiento & purificación , Neuronas/química , Sistemas Neurosecretores/química , Péptidos/aislamiento & purificación , Precursores de Proteínas/aislamiento & purificación , Secuencia de Aminoácidos , Animales , Proteínas de Artrópodos , Secuencia de Bases , Bioensayo , Glucemia/metabolismo , Braquiuros , Clonación Molecular , ADN Complementario/genética , Ecdisteroides , Hemolinfa , Hormonas de Invertebrados/genética , Masculino , Modelos Genéticos , Datos de Secuencia Molecular , Péptidos/genética , Precursores de Proteínas/genética , Análisis de Secuencia de ADN , Esteroides/metabolismo , Distribución TisularRESUMEN
The water in the nebulizer of respirators is a potential source of infection for patients receiving artificial respiration. Interposition of a special equipment that will produce ozone-free ultraviolet radiation will prevent infection of the patient by the inspired humidified air, even if the bacterial count in the nebulizer fluid is very high. Interposition of the same equipment on the expiratory side is also recommended to minimize the risk of infection of the environment by bacteria in the expired air.
