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1.
Thomas C. Noonan David F. Kern Asrar B. Malik 《Prostaglandins & other lipid mediators》1985,30(3):419-434
The pulmonary microvascular responses to leukotrienes B4, C4 and D4 (total dosage of 4 μg/kg i.v.) were examined in acutely-prepared halothane anesthetized and awake sheep prepared with lung lymp fistulas. In anesthetized as well as unanesthetized sheep, LTB4 caused a marked and transient decrease in the circulating leukocyte count. Pulmonary transvascular protein clearance (pulmonary lymph flow x lymph-to-plasma protein concentration ratio) increased transiently in awake sheep, suggesting a small increase in pulmonary vascular permeability. The mean pulmonary artery pressure (P
) also increased. In the acutely-prepared sheep, the LTB4-induced pulmonary hemodynamic and lymph flow responses were damped. Leukotriene C4 increased P
to a greater extent in awake sheep than in anesthetized sheep, but did not significantly affect the pulmonary lymph flow rate (Q̇lym) and lmph-to-plasma protein concentration (L/P) ration in either group. LTD4 increased P
and Q̇lymp in both acute and awake sheep; Q̇lym increased without a significant change in the L/P ratio. The LTD4-induced rise in P
occurred in association with an increase in plasma thromboxane B2 (Txb2) cocentration. The relativity small increase in Q̇lym with LTD4 suggests that the increase in the transvascular fluid filtration rate is the result of a rise in the pulmonary capillary hydrostatic pressure. In conclusion, LTB4 induces a marked neutropenia, pulmonary hypertension, and may transiently increase lung vascular permeability. Both LTC4 and LTD4 cause a similar degree of pulmonary hypertension in awake sheep, but had different lymph flow responses which may be due to pulmonary vasoconstriction at different sites, i.e. greather pre-capillary constriction with LTC4 because Q̇lym did not change and greater post-capillary constriction with LTD4 because Q̇ increased with the same rise in P
. 相似文献
2.
Michael S. Goligorsky Hirokazu Tsukahara Harold Magazine Thomas T. Andersen Asrar B. Malik Wadie F. Bahou 《Journal of cellular physiology》1994,158(3):485-494
Cellular mechanisms responsible for the termination of ET-1 signal are poorly understood. In order to examine the hypothesis that nitric oxide serves as a physiological brake of ET- 1 signaling, Chinese hamster ovary (CHO) cells stably transfected with the ETA receptor cDNA (CHO-ET) were studied. CHO-ET responded to ET-1 with robust [Ca2+], transients and developed a long-lasting homologous desensitization. Donors of nitric oxide (NO), 3-morpholino-sydnonimine HCl(SIN-1), or sodium nitroprusside (SNP) reduced the amplitude of these responses, accelerated the rate of [Ca2+], recovery, and counteracted the development of homologous desensitization by a cyclic GMP-independent mechanism, suggesting an alternative mode for NO modulation of ET-1 responses. Stimulation of CHO-ET cells with mastoparan, a wasp venom acting directly on G proteins (bypassing receptor activation), was inhibited by NO, revealing a postreceptoral target for NO-induced modulation of [Ca2+] mobilization. Using a lys9-biotinylated ET-1 (ET-1 [BtK9]), binding sites were “mapped” in CHO-ET cells. Receptor-ligand complexes did not exhibit spontaneous dissociation during 60min observations. Quantitative fluorescence microscopy revealed that SNP or SIN-1 caused a rapid, concentration-dependent, and reversible dissociation of biotinylated ET- 1 from ETA receptor (EC50 = 75 μM and 6 μM, respectively), an effect that was not mimicked by 8-bromo-cyclic GMP. “Sandwich” co-culture of endothelial cells with CHO-ET showed that activation of NO production by endothelial cells similarly resulted in dissociation of ET-1 [BtK9] from ETA receptors. We hypothesize that NO plays a role in physiological termination of ET-1 signalling by dual mechanisms: (1) displacement of bound ET-1 from its receptor, thus preventing homologous desensitization, and (2) interference with the postreceptoral pathway for [Ca2+] mobilization, hence inhibiting end-responses to ET-1. © 1994 Wiley-Liss, Inc. 相似文献
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Mohammed Rafi Shaik Rabbani Syed Syed Farooq Adil Mufsir Kuniyil Mujeeb Khan Mohammed S. Alqahtani Jilani P. Shaik Mohammed Rafiq H. Siddiqui Abdulrahman Al-Warthan Mohammed A.F. Sharaf Abdelatty Abdelgawad Emad Mahrous Awwad 《Saudi Journal of Biological Sciences》2021,28(2):1196-1202
Due to their inexpensive and eco-friendly nature, and existence of manganese in various oxidation states and their natural abundance have attained significant attention for the formation of Mn3O4 nanoparticles (Mn3O4 NPs). Herein, we report the preparation of Mn3O4 nanoparticles using manganese nitrate as a precursor material by utilization of a precipitation technique. The as-prepared Mn3O4 nanoparticles (Mn3O4 NPs) were characterized by using X-ray powder diffraction (XRD), UV–Visible spectroscopy (UV–Vis), High-Resolution Transmission electron microscopy (HRTEM), Field emission scanning electron microscopy (FESEM), Thermal gravimetric analysis (TGA) and Fourier-transform infrared spectroscopy (FT-IR). The antimicrobial properties of the as-synthesized Mn3O4 nanoparticles were investigated against numerous bacterial and fungal strains including S. aureus, E. coli, B. subtilis, P. aeruginosa, A. flavus and C. albicans. The Mn3O4 NPs inhibited the growth of S. aureus with a minimum inhibitory concentration (MIC) of 40 μg/ml and C. albicans with a MIC of 15 μg/ml. Furthermore, the Mn3O4 NPs anti-cancer activity was examined using MTT essay against A549 lung and MCF-7 breast cancer cell lines. The Mn3O4 NPs revealed significant activity against the examined cancer cell lines A549 and MCF-7. The IC50 values of Mn3O4 NPs with A549 cell line was found at concentration of 98 µg/mL and MCF-7 cell line was found at concentration of 25 µg/mL. 相似文献
6.
BackgroundSusumu Ohno’s idea that modern vertebrates are degenerate polyploids (concept referred as 2R hypothesis) has been the subject of intense debate for past four decades. It was proposed that intra-genomic synteny regions (paralogons) in human genome are remains of ancient polyploidization events that occurred early in the vertebrate history. The quadruplicated paralogon centered on human HOX clusters is taken as evidence that human HOX-bearing chromosomes were structured by two rounds of whole genome duplication (WGD) events.ResultsEvolutionary history of human HOX-bearing chromosomes (chromosomes 2/7/12/17) was evaluated by the phylogenetic analysis of multigene families with triplicated or quadruplicated distribution on these chromosomes. Topology comparison approach categorized the members of 44 families into four distinct co-duplicated groups. Distinct gene families belonging to a particular co-duplicated group, exhibit similar evolutionary history and hence have duplicated simultaneously, whereas genes of two distinct co-duplicated groups do not share their evolutionary history and have not duplicated in concert with each other.ConclusionThe recovery of co-duplicated groups suggests that “ancient segmental duplications and rearrangements” is the most rational model of evolutionary events that have generated the triplicated and quadruplicated paralogy regions seen on the human HOX-bearing chromosomes. 相似文献
7.
MA Abo-El Seoud MM Sarhan AE Omar MM Helal 《Archives Of Phytopathology And Plant Protection》2013,46(3):175-184
Essential oils of fennel, peppermint, caraway, eucalyptus, geranium and lemon were tested for their antimicrobial activities against some plant pathogenic micro-organisms (Fusarium oxysporum, Alternaria alternate, Penicilium italicum Penicilium digitatum and Botyritus cinerea). Essential oils of fennel, peppermint, caraway were selected as an active ingredient for the formulation of biocides due to their efficiency in controlling the tested micro-organisms. Successful emulsifiable concentrates (biocides) were prepared from these oils using different emulsifiers (Emulgator B.L.M. Tween20 and Tween80) and different fixed oils (sesame, olive, cotton and soybean oils). Physico-chemical properties of the formulated biocide (spontaneous emulsification, emulsion stability test, cold stability and heat stability tests as well as viscosity, surface tension and pH) were measured. The prepared biocides were ready to be tested for application in a future work as a safe pesticide against different pathogens. 相似文献
8.
Sihem Dabbou Samia Dabbou Guido Flamini Gaetano Pandino Laura Gasco Ahmed Noureddine Helal 《化学与生物多样性》2016,13(11):1475-1483
The phytochemical composition in two Tunisian globe artichoke cultivars (bracts, leaves, and floral stems) was evaluated in the plant byproducts. The results indicated that the bracts contain the highest levels of total phenols, o‐diphenols, and flavonoids, whereas tannins seem to be more abundant in the leaves. Bracts from the ‘Violet d'Hyères’ cultivar possessed more total phenols (160.8 mg/g DW), flavonoids (64.9 mg/g DW), and anthocyanins (15.3 μg/g DW) than the ‘Blanc d'Oran’ bracts (134.5 mg/g DW, 51.2 mg/g DW, and 8.3 μg/g DW, resp.). Sixty‐four volatile compounds were identified in the headspace of globe artichoke material, particularly in the bracts. The volatile profile showed that sesquiterpene hydrocarbons and non‐terpene derivatives were the main volatiles emitted by the bracts in both cultivars. These results suggest that globe artichoke byproducts might represent a potential source of natural compounds, which could be used as nutraceuticals or as ingredients in the design of functional foods. 相似文献
9.
Parathyroid hormone-related protein (PTHrP), a oncofetal gene product possessing smooth muscle relaxant properties, has been found in rat and human uterine smooth muscle cells (USMC) where it is postulated to regulate myometrial tone and/or blood flow. Studies investigating the gestational regulation of PTHrP in human USMC have not been performed. This study was conducted to determine if pregnancy alters the capacity of USMC to secrete or respond to PTHrP. USMC cultures were established from 8 hysterectomy specimens (H) and 7 non-laboring (NP) and 5 laboring term pregnant uterine biopsies (LP). PTHrP secretion was measured at baseline and in response to TGF-beta1 using a immunoradiometric assay. The USMC response to PTHrP was assessed by incubating cultures with human (1-34)PTHrP and measuring cellular cAMP by radioimmunoassay. We found that cultures from the groups did not differ with respect to basal PTHrP secretion. TGF-beta1, on the other hand, produced dose-dependent increases in secreted PTHrP in each group such that LP>NP>H at 12 hrs and LP>NP and H 24 hrs. Maximal responses were found at 24 hrs in cells treated with 10 ng/ml TGF-beta1 (LP: 2034+/-366 vs NP: 1485+/-427; H: 1250+/-202 fmol/mg). Incubation of cultures with PTHrP produced dose-dependent increases in cAMP production, with 10(-7) M increasing levels by 64%. Neither pregnancy nor labor significantly affected the cAMP response. These findings indicate that the human myometrium has the capacity to increase PTHrP secretion during pregnancy and labor through a TGF-beta-dependent pathway. Such findings are consistent with a role of PTHrP in enhancing uterine blood flow. 相似文献
10.
Helal CJ Sanner MA Cooper CB Gant T Adam M Lucas JC Kang Z Kupchinsky S Ahlijanian MK Tate B Menniti FS Kelly K Peterson M 《Bioorganic & medicinal chemistry letters》2004,14(22):5521-5525
High-throughput screening with cyclin-dependent kinase 5 (cdk5)/p25 led to the discovery of N-(5-isopropyl-thiazol-2-yl)isobutyramide (1). This compound is an equipotent inhibitor of cdk5 and cyclin-dependent kinase 2 (cdk2)/cyclin E (IC(50)=ca. 320nM). Parallel and directed synthesis techniques were utilized to explore the SAR of this series. Up to 60-fold improvements in potency at cdk5 and 12-fold selectivity over cdk2 were achieved. 相似文献