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941.
A. S. M. Towhidul Alam Christopher L. -H. Huang David R. Blake Mone Zaidi 《Bioscience reports》1992,12(5):369-380
Several important conclusions have recently emerged fromin vitro studies on the resorptive cell of bone, the osteoclast. First, it has been established that osteoclast function is modulated locally, by changes in the local concentration of Ca2+ caused by hydroxyapatite dissolution. It is thought that activation by Ca2+ of a surface membrane Ca2+ receptor mediates these effects, hence providing a feedback control. Second, a number of molecules produced locally by the endothelial cell, with which the osteoclast is in intimate contact, have been found to affect bone resorption profoundly. For instance, the autocoid nitric oxide strongly inhibits bone resorption. Finally, reactive oxygen species have been found to aid bone resorption and enhance osteoclastic activity directly. Here, we will attempt to integrate these control mechanisms into a unified hypothesis for the local control of bone resorption. 相似文献
942.
This article considers ethnomedical knowledge and practices among parents related to contraction of acute gastroenteritis among children in Peshawar, Pakistan. Research methods included analysis of the Emergency Pediatric Services’ admission register, a structured interview administered to 47 parents of patients seen in the Khyber Medical College Teaching Hospital, semi-structured interviews of 12 staff, and four home visits among families with children treated at the hospital. The use of native research assistants and participant observation contributed to the reliability of the findings, though the ethnographic, home-visit sample is small. Our research indicated that infection rates are exacerbated in homes through two culturally salient practices and one socioeconomic condition. Various misconceptions propagate the recurrence or perserverance of acute gastroenteritis including assumptions about teething leading to poor knowledge of disease etiology, rehydration solutions leading to increased severity of disease, and diaper usage leading to the spread of disease. In our Discussion, we suggest how hospital structures of authority and gender hierarchy may impact hospital interactions, the flow of information, and its respective importance to the patient’s parents leading to possible propagation of disease. These ethnographic data offer a relatively brief but targeted course of action to improve the effectiveness of prevention and treatment efforts. 相似文献
943.
Nousheen Zaidi Leslie Lupien Nancy B. Kuemmerle William B. Kinlaw Johannes V. Swinnen Karine Smans 《Progress in lipid research》2013,52(4):585-589
One of the most important metabolic hallmarks of cancer cells is enhanced lipogenesis. Depending on the tumor type, tumor cells synthesize up to 95% of saturated and mono-unsaturated fatty acids (FA) de novo in spite of sufficient dietary lipid supply. This lipogenic conversion starts early when cells become cancerous and further expands as the tumor cells become more malignant. It is suggested that activation of FA synthesis is required for carcinogenesis and for tumor cell survival. These observations suggest that the enzymes involved in FA synthesis would be rational therapeutic targets for cancer treatment. However, several recent reports have shown that the anti-tumor effects, following inhibition of endogenous FA synthesis in cancer cell lines may be obviated by adding exogenous FAs. Additionally, high intake of dietary fat is reported to be a potential risk factor for development and poor prognosis for certain cancers. Recently it was reported that breast and liposarcoma tumors are equipped for both de novo fatty acid synthesis pathway as well as LPL-mediated extracellular lipolysis. These observations indicate that lipolytically acquired FAs may provide an additional source of FAs for cancer. This review focuses on our current understanding of lipogenic and lipolytic pathways in cancer cell progression. 相似文献
944.
Sheetal Uppal Shikha Salhotra Nitika Mukhi Fatima Kamal Zaidi Manas Seal Somdatta Ghosh Dey Rajiv Bhat Suman Kundu 《The Journal of biological chemistry》2015,290(4):1979-1993
Heme proteins, which reversibly bind oxygen and display a particular fold originally identified in myoglobin (Mb), characterize the “hemoglobin (Hb) superfamily.” The long known and widely investigated Hb superfamily, however, has been enriched by the discovery and investigation of new classes and members. Truncated Hbs typify such novel classes and exhibit a distinct two-on-two α-helical fold. The truncated Hb from the freshwater cyanobacterium Synechocystis exhibits hexacoordinate heme chemistry and bears an unusual covalent bond between the nonaxial His117 and a heme porphyrin 2-vinyl atom, which remains tightly associated with the globin unlike any other. It seems to be the most stable Hb known to date, and His117 is the dominant force holding the heme. Mutations of amino acid residues in the vicinity did not influence this covalent linkage. Introduction of a nonaxial His into sperm whale Mb at the topologically equivalent position and in close proximity to vinyl group significantly increased the heme stability of this prototype globin. Reversed phase chromatography, electrospray ionization-MS, and MALDI-TOF analyses confirmed the presence of covalent linkage in Mb I107H. The Mb mutant with the engineered covalent linkage was stable to denaturants and exhibited ligand binding and auto-oxidation rates similar to the wild type protein. This indeed is a novel finding and provides a new perspective to the evolution of Hbs. The successful attempt at engineering heme stability holds promise for the production of stable Hb-based blood substitute. 相似文献
945.
Barbara S. Zielinski Kim Fredricks Rod McDonald Aliya U. Zaidi 《Brain Cell Biology》2005,34(3-5):209-216
This study examined olfactory sensory neuron morphology and physiological responsiveness in newly hatched sea lamprey, Petromyzon marinus L. These prolarvae hatch shortly after neural tube formation, and stay within nests for approximately 18 days, before moving downstream to silty areas where they burrow, feed and pass to the larval stage. To explore the possibility that the olfactory system is functioning during this prolarval stage, morphological and physiological development of olfactory sensory neurons was examined. The nasal cavity contained an olfactory epithelium with ciliated olfactory sensory neurons. Axons formed aggregates in the basal portion of the olfactory epithelium and spanned the narrow distance between the olfactory epithelium and the brain. The presence of asymmetric synapses with agranular vesicles within fibers in the brain, adjacent to the olfactory epithelium suggests that there was synaptic connectivity between olfactory sensory axons and the brain. Neural recordings from the surface of the olfactory epithelium showed responses following the application of L-arginine, taurocholic acid, petromyzonol sulfate (a lamprey migratory pheromone), and water conditioned by conspecifics. These results suggest that lampreys may respond to olfactory sensory input during the prolarval stage. 相似文献
946.
H Elmahmoudi F Ben-Lakhal W Elborji A Jlizi K Zahra R Sassi M Zorgan B Meddeb A Elgaaied Ben Ammar E Gouider 《Diagnostic pathology》2012,7(1):92
ABSTRACT: Inherited factor VII (FVII) deficiency is a rare disorder characterized by a bleeding phenotype varying from mild to severe. To date, more than 200 mutations have been described along the F7 gene encoding for FVII. The aim of this study was the identification of genetic defects underlying FVII deficiency in 10 patients belonging to eight unrelated families of the North provinces from Tunisia. Mutation detection was performed by sequencing the whole F7 gene coding region, exon-intron boundaries and about 400 bp of the promoter region. We identified 5 mutations in five unrelated families; the novel p.F328Y mutation and the reported mutations: p.R304Q, p.M298I, IVS1aG > A and nt1005C > T. For the remaining 5 patients we didn't identified any mutations using PCR/Sequencing protocol. In conclusion, this study represents the first comprehensive molecular series of FVII deficiency affected patients in Tunisia from the North. We will try in the future to continue the molecular study for Tunisian patients from Center and South provinces in order to have a complete idea about the FVII deficiency mutational profile in our country. Virtual slides The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1288044089753085. 相似文献
947.
Asma Ben Ghnaya Annick Hourmant Stéphane Cerantola Nelly Kervarec Jean Yves Cabon Michel Branchard Gilbert Charles 《Plant Cell, Tissue and Organ Culture》2010,102(2):191-197
To gain more insight into the impact of zinc on the primary metabolites in rapeseed, plants were regenerated in vitro in the
presence of zinc (0.1–1 mM), acclimatized, transferred to a greenhouse, and treated with 2 mM ZnSO4. The main metabolites, including soluble carbohydrates and free amino acids, were analyzed by nuclear magnetic resonance
spectroscopy, and further confirmed by spectrophotometry and enzymatic analyses. Exposure of these greenhouse-grown plants
to ZnSO4 led to both a significant rise of the total amino acid level and an increase of proline accumulation in the different tissues.
Moreover, the control plants, regenerated without zinc stress, exhibited a significant reduction of soluble carbohydrate levels,
whereas the plants derived from Zn-treated regenerants exhibited significantly higher levels of both glucose and sucrose.
These levels increased proportionally with the Zn concentration in the regeneration step. 相似文献