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排序方式: 共有573条查询结果,搜索用时 15 毫秒
101.
Ke W Bethel CR Papp-Wallace KM Pagadala SR Nottingham M Fernandez D Buynak JD Bonomo RA van den Akker F 《Antimicrobial agents and chemotherapy》2012,56(5):2713-2718
Class A carbapenemases are a major threat to the potency of carbapenem antibiotics. A widespread carbapenemase, KPC-2, is not easily inhibited by β-lactamase inhibitors (i.e., clavulanic acid, sulbactam, and tazobactam). To explore different mechanisms of inhibition of KPC-2, we determined the crystal structures of KPC-2 with two β-lactamase inhibitors that follow different inactivation pathways and kinetics. The first complex is that of a small boronic acid compound, 3-nitrophenyl boronic acid (3-NPBA), bound to KPC-2 with 1.62-Å resolution. 3-NPBA demonstrated a Km value of 1.0 ± 0.1 μM (mean ± standard error) for KPC-2 and blocks the active site by making a reversible covalent interaction with the catalytic S70 residue. The two boron hydroxyl atoms of 3-NPBA are positioned in the oxyanion hole and the deacylation water pocket, respectively. In addition, the aromatic ring of 3-NPBA provides an edge-to-face interaction with W105 in the active site. The structure of KPC-2 with the penam sulfone PSR-3-226 was determined at 1.26-Å resolution. PSR-3-226 displayed a Km value of 3.8 ± 0.4 μM for KPC-2, and the inactivation rate constant (kinact) was 0.034 ± 0.003 s−1. When covalently bound to S70, PSR-3-226 forms a trans-enamine intermediate in the KPC-2 active site. The predominant active site interactions are generated via the carbonyl oxygen, which resides in the oxyanion hole, and the carboxyl moiety of PSR-3-226, which interacts with N132, N170, and E166. 3-NPBA and PSR-3-226 are the first β-lactamase inhibitors to be trapped as an acyl-enzyme complex with KPC-2. The structural and inhibitory insights gained here could aid in the design of potent KPC-2 inhibitors. 相似文献
102.
Flexible choledochoscope was used in 16 patients undergoing common bile duct (CBD) exploration for suspected stones. Stones were found in the CBD in 4 patients in whom introperative cholangiogram was normal. T-tube cholangiogram done between the 10th and 14th postoperative days was normal in all 16 patients. None of the patients had symptoms suggestive of retained stones during follow-up ranging from 6 to 19 months. We feel that the use of choledochoscopy in patients undergoing CBD exploration will help reduce the incidence of retained stones.KEY WORDS: Cholangiography, Choledocholithiasis, Choledochoscopy 相似文献
103.
PLK DE SYLVA KM SHAH H MANI AK HUKKOO S BHATTACHARYA YOGESH CHANDER 《Medical Journal Armed Forces India》1998,54(3):182-184
The interaction of Herpes zoster and Human Immunodeficiency Virus (HIV) was evaluated in 120 cases of herpes zoster admitted to our hospital and in 157 HIV positive cases detected in the hospital during the same period. The incidence of HIV seropositivity was 22.5 per cent in cases of herpes zoster without AIDS defining disease conditions. Whereas the incidence of Herpes zoster in cases detected to be HIV positive in the same period was 17.2 per cent. A large number of herpes zoster cases found to be HIV positive were in the sexually active age group viz. 21-30 years. Thoracic dermatomal segments were most frequently involved. None of the cases had severe complications or showed evidence of progression to symptomatic HIV disease.KEY WORDS: Herpes zoster, HIV infection 相似文献
104.
105.
Not only does breast milk provides an ideal nutrient composition for the newborn, but it also contains a variety of substances that may actively influence growth and development of the infant and stimulate neonatal protection against gastrointestinal diseases. Hormones, growth factors, cytokines and even whole cells are present in breast milk and act to establish biochemical and immunological communication between mother and child. In addition, milk nutrients such as nucleotides, glutamine and lactoferrin have been shown to influence gastrointestinal development and host defense. The unique properties of milk as a mediator of biochemical messages will be presented and the clinical significance of breastfeeding in the prevention of neonatal gastrointestinal diseases will be discussed. 相似文献
106.
It is now clear that parenteral growth hormone (GH) therapy stimulates growth and increases the adult stature of girls with Turner syndrome. In addition, oestrogens are given to almost all girls with this syndrome because of primary hypogonadism. Oestrogens influence both growth and maturation of the epiphyseal growth plates. Therefore, the form and timing of oestrogen therapy may have an important impact on the outcome of other growth-promoting therapies. To examine the impact of the timing of oestrogen initiation on growth, a randomized trial was conducted in patients with Turner syndrome who were receiving GH. Some patients received oestrogen at 12 years of age, while in others this treatment was not started until 15 years of age. Those girls that received oestrogen later were significantly taller as adults. The single most important factor in determining height gain appeared to be the number of years of GH therapy prior to the initiation of oestrogen treatment. 相似文献
107.
108.
SM Weinberg SD Naidoo KM Bardi CA Brandon K Neiswanger JM Resick RA Martin ML Marazita 《Orthodontics & craniofacial research》2009,12(4):271-281
Authors – Weinberg SM, Naidoo SD, Bardi KM, Brandon CA, Neiswanger K, Resick JM, Martin RA, Marazita ML Objective – Various lines of evidence suggest that face shape may be a predisposing factor for non‐syndromic cleft lip with or without cleft palate (CL/P). In the present study, 3D surface imaging and statistical shape analysis were used to evaluate face shape differences between the unaffected (non‐cleft) parents of individuals with CL / P and unrelated controls. Methods – Sixteen facial landmarks were collected from 3D captures of 80 unaffected parents and 80 matched controls. Prior to analysis, each unaffected parent was assigned to a subgroup on the basis of prior family history (positive or negative). A geometric morphometric approach was utilized to scale and superimpose the landmark coordinate data (Procrustes analysis), test for omnibus group differences in face shape, and uncover specific modes of shape variation capable of discriminating unaffected parents from controls. Results – Significant disparity in face shape was observed between unaffected parents and controls (p < 0.01). Notably, these changes were specific to parents with a positive family history of CL / P. Shape changes associated with CL / P predisposition included marked flattening of the facial profile (midface retrusion), reduced upper facial height, increased lower facial height, and excess interorbital width. Additionally, a sex‐specific pattern of parent‐control difference was evident in the transverse dimensions of the nasolabial complex. Conclusions – The faces of unaffected parents from multiplex cleft families displayed meaningful shape differences compared with the general population. Quantitative assessment of the facial phenotype in cleft families may enhance efforts to discover the root causes of CL /P. 相似文献
109.
血小板冷藏会使血管假性血友病因子受体复合物(von Willebrand factor receptor complex)聚集成簇。巨噬细胞αMβ2 整合素结合在成簇复合物的GPIbα亚基,导致输注的冷藏血小板被快速清除。因此输注用血小板不能冷藏,但现在的室温保存方式也存在很大缺点。我们已证明αMβ2是一种凝集素,它能识别GPIbα的N-连接葡聚糖上暴露的β-N-乙酰葡萄胺。冷藏血小板的酶促半乳糖苷化阻止了αMβ2的这种识别,延长了有 相似文献
110.