兔肠致病性大肠杆菌(rEPEC)菌株RDEC-1的基因组中lifA基因与LEE (Locus for enterocyte effacement)致病岛相毗邻。本试验通过DNA序列分析、基因打靶技术、细胞因子检测以及动物试验,分析lifA基因完整核苷酸序列及其生物学功能。结果表...兔肠致病性大肠杆菌(rEPEC)菌株RDEC-1的基因组中lifA基因与LEE (Locus for enterocyte effacement)致病岛相毗邻。本试验通过DNA序列分析、基因打靶技术、细胞因子检测以及动物试验,分析lifA基因完整核苷酸序列及其生物学功能。结果表明,RDEC-1的lifA基因的核苷酸序列与人肠致病性大肠杆菌的完全相同;lifA基因具有降低家兔外周血单核细胞IL-2表达的作用。与野生型菌株RDEC-1相比,被定点敲除lifA基因的RDEC-1突变株(RDEC-1ΔlifA)口服接种家兔后,排菌量明显降低。利用野生型RDEC-1和RDEC-1ΔlifA基因缺失菌株同时口服接种家兔,从粪便中分离细菌,结果显示野生型RDEC-1是优势菌,而RDEC-1ΔlifA基因缺失菌数量极少。RDEC-1ΔlifA基因缺失菌株和野生型RDEC-1都能引起特征性家兔肠道上皮的黏附与细胞脱落病变(A/Elesion)。表明rEPEC的lifA基因在免疫调节和细菌的肠道定居中起重要作用,这为研究lifA基因的生物学功能提供了直接证据。展开更多
Background: Lifa disease (Frictional dermal melanosis over bony prominences) has been described in Iraq for the first time in 1993, as a new distinctive pigmentary skin condition that followed chronic friction with a ...Background: Lifa disease (Frictional dermal melanosis over bony prominences) has been described in Iraq for the first time in 1993, as a new distinctive pigmentary skin condition that followed chronic friction with a body washing agent (lifa) during bathing. Objective: To assess this increasingly common problem where still many doctors unaware about its presence especially in other Middle East countries. Patients and Methods: A case series descriptive study done in Departments of Dermatology-Najaf and Baghdad Teaching Hospitals, between March 2007- Oct.2008. Full history and clinical examination were done for all patients including Wood's light examination. Biopsies were taken from 21 patients and sent for hematoxylin-eosin and Congo red stains. Results: Fifty two (49 female and 3 male) patients with typical clinical features of lifa disease were studied. The mean age of presentation was 27.92 ± 7.58 years. All patients were slim with prominent bones and low body mass index, used lifa vigorously during bathing.Pigmentation was distributed bilaterally and symmetrically over bony prominences. The most common affected sites were: clavicular areas (67.3%) and upper back (42%). Wood's light and histopathological examinations revealed dermal melanosis. No amyloid deposit was detected by using Congo red stain in any patient. Conclusions: Lifa disease is a common distinctive pigmentary disfiguring problem especially among females. The histopathology showed dermal melanosis, and might be confused with other pigmentary problems like macular amyloidosis.展开更多
基金NIDDK 1RO1DK51507 (ECB)VA/DOD Merit Review Award
文摘兔肠致病性大肠杆菌(rEPEC)菌株RDEC-1的基因组中lifA基因与LEE (Locus for enterocyte effacement)致病岛相毗邻。本试验通过DNA序列分析、基因打靶技术、细胞因子检测以及动物试验,分析lifA基因完整核苷酸序列及其生物学功能。结果表明,RDEC-1的lifA基因的核苷酸序列与人肠致病性大肠杆菌的完全相同;lifA基因具有降低家兔外周血单核细胞IL-2表达的作用。与野生型菌株RDEC-1相比,被定点敲除lifA基因的RDEC-1突变株(RDEC-1ΔlifA)口服接种家兔后,排菌量明显降低。利用野生型RDEC-1和RDEC-1ΔlifA基因缺失菌株同时口服接种家兔,从粪便中分离细菌,结果显示野生型RDEC-1是优势菌,而RDEC-1ΔlifA基因缺失菌数量极少。RDEC-1ΔlifA基因缺失菌株和野生型RDEC-1都能引起特征性家兔肠道上皮的黏附与细胞脱落病变(A/Elesion)。表明rEPEC的lifA基因在免疫调节和细菌的肠道定居中起重要作用,这为研究lifA基因的生物学功能提供了直接证据。
文摘Background: Lifa disease (Frictional dermal melanosis over bony prominences) has been described in Iraq for the first time in 1993, as a new distinctive pigmentary skin condition that followed chronic friction with a body washing agent (lifa) during bathing. Objective: To assess this increasingly common problem where still many doctors unaware about its presence especially in other Middle East countries. Patients and Methods: A case series descriptive study done in Departments of Dermatology-Najaf and Baghdad Teaching Hospitals, between March 2007- Oct.2008. Full history and clinical examination were done for all patients including Wood's light examination. Biopsies were taken from 21 patients and sent for hematoxylin-eosin and Congo red stains. Results: Fifty two (49 female and 3 male) patients with typical clinical features of lifa disease were studied. The mean age of presentation was 27.92 ± 7.58 years. All patients were slim with prominent bones and low body mass index, used lifa vigorously during bathing.Pigmentation was distributed bilaterally and symmetrically over bony prominences. The most common affected sites were: clavicular areas (67.3%) and upper back (42%). Wood's light and histopathological examinations revealed dermal melanosis. No amyloid deposit was detected by using Congo red stain in any patient. Conclusions: Lifa disease is a common distinctive pigmentary disfiguring problem especially among females. The histopathology showed dermal melanosis, and might be confused with other pigmentary problems like macular amyloidosis.