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Abstract
Integrins are a family of heterodimeric receptors, which modulate many cellular processes including: growth, death (apoptosis), adhesion, migration, and invasion by activating several signaling pathways. Integrin-binding RGD (arginine-glycine-aspartic acid) is found in several important extracellular matrix proteins which serve as adhesive integrin ligands. The RGD motif has also been found in many toxins from snake venom and other sources that specifically inhibit integrin binding function and serve as potent integrin antagonists, particularly of platelet aggregation and integrin-mediated cell adhesion. Many of these proteins have potential as therapeutic agents which can target integrins directly. Structural and functional studies of several RGD-containing toxins suggest that the inhibitory potency of these proteins lies in subtle positional requirements of the tripeptide RGD at the tip of a flexible loop, a structural feature for binding to integrins. In addition, amino acid residues in this loop in close vicinity to the RGD-motif determine the integrin-binding specificity and selectivity. This review will present a review of integrin structure and function, and of disintegrin structural features responsible for their activity as antagonists of integrin function. The use of integrins in drug targeting and integrins as targets for drug delivery by using the RGD as a template structure will also be discussed.
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Wessmann A, Lu D, Lamb CR, Smyth B, Mantis P, Chandler K, Boag A, Cherubini GB, Cappello R. Brain and spinal cord haemorrhages associated with Angiostrongylus vasorum
infection in four dogs. Vet Rec 2006; 158:858-63. [PMID: 16798954 DOI: 10.1136/vr.158.25.858] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Multifocal haemorrhages associated with Angiostrongylus vasorum infection were observed in the central nervous system of four dogs with neurological signs including depression, seizures, spinal pain and paresis. In magnetic resonance images the majority of the lesions were isointense or slightly hyperintense in T1-weighted images, hyperintense in T2-weighted images and hypointense in T2*-weighted (gradient echo) images, compatible with haemorrhages more than seven days old. Lesions were found in the brain of three of the dogs and in the spinal cord of two. The cerebrospinal fluid contained high concentrations of protein and evidence of erythrophagia. All the dogs had coagulopathy and pulmonary haemorrhage of varying severity. A vasorum larvae were detected in the faeces of each of the dogs. Neural A vasorum was confirmed at postmortem examination in two dogs.
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228
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Equils O, Naiki Y, Shapiro AM, Michelsen K, Lu D, Adams J, Jordan S. 1,25-Dihydroxyvitamin D inhibits lipopolysaccharide-induced immune activation in human endothelial cells. Clin Exp Immunol 2006; 143:58-64. [PMID: 16367934 PMCID: PMC1809565 DOI: 10.1111/j.1365-2249.2005.02961.x] [Citation(s) in RCA: 105] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
In addition to its well-known role in mineral and skeletal homeostasis, 1,25-dihydroxyvitamin D3 [1,25-(OH)2, D3] regulates the differentiation, growth and function of a broad range of immune system cells, including monocytes, dendritic cells, T and B lymphocytes. Vascular endothelial cells play a major role in the innate immune activation during infections, sepsis and transplant rejection; however, currently there are no data on the effect of 1,25-(OH)2 D3 on microbial antigen-induced endothelial cell activation. Here we show that 1,25-(OH)2 D3 pretreatment of human microvessel endothelial cells (HMEC) inhibited the enteric gram-negative bacterial lipopolysaccharide (LPS) activation of transcription factor NF-kappaB and interleukin (IL)-6, IL-8 and regulated upon activation normal T cell exposed and secreted (RANTES) release. The effect of 1,25-(OH)2 D3 was not due to increased cell death or inhibition of endothelial cell proliferation. 1,25-(OH)2 D3 pretreatment of HMEC did not block MyD88-independent LPS-induced interferon (IFN)-beta promoter activation. 1,25-(OH)2 D3 pretreatment of HMEC did not modulate Toll-like receptor 4 (TLR4) or MD-2 expression. These data suggest that 1,25-(OH)2 D3 may play a role in LPS-induced immune activation of endothelial cells during gram-negative bacterial infections, and a suggest a potential role for 1,25-(OH)2 D3 and its analogues as an adjuvant in the treatment of gram-negative sepsis.
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229
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Al-Azzawi H, Mathur A, Lu D, Swartz-Basile D, Nakeeb A, Pitt H. Pioglitazone increases gallbladder volume in insulin- resistant obese mice. J Surg Res 2006. [DOI: 10.1016/j.jss.2005.11.107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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230
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Swartz-Basile D, Lu D, Tran K, Graewin S, Nakeeb A, Pitt H. Advanced glycation end products accumulate in the diabetic gallbladder. J Surg Res 2006. [DOI: 10.1016/j.jss.2005.11.410] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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231
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Chen S, Lu D, Zhang M, Che J, Yin Z, Zhang S, Zhang W, Bo X, Ding Y, Wang S. Double-antigen sandwich ELISA for detection of antibodies to SARS-associated coronavirus in human serum. Eur J Clin Microbiol Infect Dis 2005; 24:549-53. [PMID: 16133409 PMCID: PMC7088218 DOI: 10.1007/s10096-005-1378-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The study presented here was conducted to evaluate the performance of a double-antigen sandwich ELISA to detect antibodies in human serum against the coronavirus associated with severe acute respiratory syndrome (SARS). A recombinant partial nucleocapsid protein of SARS-associated coronavirus was used as a serodiagnostic antigen in the ELISA. A total of 2892 clinical serum samples were tested with the ELISA kit, which positively identified 25 of 35 (71.4%) samples of patients with confirmed SARS infection, 286 of 407 (70%) samples of patients suspected of having SARS, 229 of 302 (75.8%) samples of convalescent SARS patients, and 0 of 544 samples obtained from healthcare workers; only 1 of 1604 clinical samples obtained from patients with other diseases demonstrated a weakly positive result. These results indicate that the double-antigen sandwich ELISA is an effective screening method for the serodiagnosis of SARS-associated coronavirus.
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232
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Whited KL, Lu D, Tso P, Kent Lloyd KC, Raybould HE. Apolipoprotein A-IV is involved in detection of lipid in the rat intestine. J Physiol 2005; 569:949-58. [PMID: 16239275 PMCID: PMC1464270 DOI: 10.1113/jphysiol.2005.097634] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Long chain triglyceride (>C12) in the intestinal lumen potently inhibits gastric emptying and acid secretion via the vagal afferent pathway. While the mechanism of inhibition involves the formation of chylomicrons, the essential role of the apolipoprotein apo A-IV is unclear. Using apo A-IV(-/-) mice, we tested the hypothesis that inhibition of gastric emptying and gastric acid secretion in response to dietary lipid is dependent upon apo A-IV. As measured by nuclear scintigraphy in awake mice, gastric emptying of an ingested whole-egg meal was significantly faster in apo A-IV(-/-) knockout versus A-IV(+/+) controls (34 +/- 1 versus 54 +/- 3 min, P < 0.0001). In anaesthetized A-IV(+/+) mice, meal-stimulated gastric acid secretion was 59% inhibited by intestinal lipid infusion; this was abolished in apo A-IV(-/-) mice. Oral gavage of lipid in awake mice activated neurones throughout the nucleus of the solitary tract (NTS) in A-IV(+/+) mice, measured by immunohistochemical localization of Fos protein expression. However, in the mid region of the NTS (bregma -7.32 to -7.76 mm), Fos expression in response to intestinal lipid was significantly decreased by 50% in apo A-IV(-/-) mice compared to A-IV(+/+) controls. We conclude that activation of the vagal afferent pathway and inhibition of gastric function in response to dietary lipid is partly dependent upon apo A-IV.
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233
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McLaughlin PJ, Brown CM, Winston KM, Thakur G, Lu D, Makriyannis A, Salamone JD. The novel cannabinoid agonist AM 411 produces a biphasic effect on accuracy in a visual target detection task in rats. Behav Pharmacol 2005; 16:477-86. [PMID: 16148454 DOI: 10.1097/00008877-200509000-00022] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Cannabinoid agonists have been shown to produce dose-related impairments in several measures of cognitive performance. However, it is unclear if low doses of cannabinoid CB1 agonists, or CB1 antagonists, can facilitate aspects of stimulus detection. The present study employed an operant procedure involving visual stimulus detection in rats. The task was found to be sensitive to the muscarinic acetylcholine antagonist scopolamine. The CB1 antagonist AM 251 did not affect stimulus detection processes across a broad range of doses. However, the novel CB1 agonist AM 411 produced a biphasic effect, with the two lowest doses (0.25 and 0.5 mg/kg) enhancing accuracy. AM 411 changed patterns of responding toward runs of consecutive errors on only one of the two levers. It produced a biphasic effect on consecutive errors on the lever associated with a higher level of errors, with decreases in errors following the lower doses (0.25 and 0.5 mg/kg) and increases following the highest dose (2.0 mg/kg). These effects were not accompanied by changes in measures of bias commonly used to uncover such patterns in rodent operant models of cognitive performance. In contrast to the cognitive impairment seen after administration of moderate to high doses of CB1 agonists, it appears that low doses of some CB1 agonists may be capable of enhancing stimulus detection processes.
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234
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Lu X, Lu D, Scully MF, Kakkar VV. Snake Venom Metalloproteinase Containing a Disintegrin-like Domain, its Structure-activity Relationships at Interacting with Integrins. ACTA ACUST UNITED AC 2005; 3:249-60. [PMID: 15974889 DOI: 10.2174/1568016054368205] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Snake venom disintegrins represent a family of RGD (Arg-Gly-Asp) or KGD (Lys-Gly-Asp)-containing proteins which have been reported to be unique and potentially useful tools not only for investigating integrin-ligand interactions, but also for the development of anti-thrombotic agents in terms of their anti-platelet activities. Snake venom proteins containing a disintegrin-like domain represent another super-family of proteins in which many of them have been demonstrated to have similar ability to inhibit platelet aggregation and integrin-mediated cell adhesion as the disintegrins. This super-family includes a large number of snake venom metalloproteinases and disintegrin related, RGD-containing snake venom proteins (disintegrin-like proteins) such as dendroaspin. Recently, a family of homologues of the snake venom metalloproteinases have been found in a wide variety of mammalian tissues as well as in other eukaryotic organisms termed ADAM (a disintegrin-like and metalloproteinase) proteins. ADAMs are members of the metazincins that also include the related matrix metalloprotease (MMPs). Some of ADAM proteins have now shown to interact with integrins, and the disintegrin-like domain may be crucial part in their function as proteases. A description of structure-activity relationships of snake venom proteins containing a disintegrin-like domain is outlined in this review, along with reports of the modulation of protein activity by recombinant mutation. Comparison is also made of the structural and functional features of the metalloproteinases in snakes compared with those from other species. The review is intended to provide insights in which may assist the development of new therapeutic approaches.
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235
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Huang XJ, Jiang Q, Chen H, Xu L, Liu D, Chen Y, Han W, Zhang Y, Liu K, Lu D. Low-dose methotrexate for the treatment of graft-versus-host disease after allogeneic hematopoietic stem cell transplantation. Bone Marrow Transplant 2005; 36:343-8. [PMID: 15968295 DOI: 10.1038/sj.bmt.1705034] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Methotrexate (MTX) is commonly used in the prophylaxis of graft-versus-host disease (GVHD) after allogeneic hematopoietic stem cell transplantation (allo-HSCT). In order to evaluate the efficacy and safety of low-dose MTX treatment in patients with GVHD after allo-HSCT, 38 patients with acute GVHD (aGVHD), chronic GVHD (cGVHD) or GVHD post-donor lymphocyte infusion (post-DLI GVHD) after allo-HSCT received intravenous MTX at a dose of 5 or 10 mg every 5-- days until a complete or partial response was seen, or there was treatment failure or intolerable side effects. The overall response rate was 94.7% (18/19 patients) in patients with aGVHD, 76.2% (16/21 patients) in patients with cGVHD and 2/2 in patients with post-DLI GVHD. The response rate for GVHD involving various organs was 100% in skin, 75% in gut, 55.6% in liver, 75% in mouth and 100% in the eye, among all enrolled patients. Side effects were minor. Short-term, low-dose MTX is a tolerable and an effective regimen for patients with aGVHD, cGVHD or post-DLI GVHD after allo-HSCT.
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236
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Williams B, Atkins A, Zhang H, Lu D, Jimenez X, Li H, Wang MN, Ludwig D, Balderes P, Witte L, Li Y, Zhu Z. Cell-based selection of internalizing fully human antagonistic antibodies directed against FLT3 for suppression of leukemia cell growth. Leukemia 2005; 19:1432-8. [PMID: 15931264 DOI: 10.1038/sj.leu.2403825] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
FMS-like tyrosine kinase 3 (FLT3) receptor is highly expressed in an array of hematological malignancies including approximately 90% of acute myelogenous leukemia (AML). Ligand stimulation of the receptor promotes the survival and proliferation of leukemia cells. Strategies targeting FLT3 using monoclonal antibodies may therefore constitute an effective therapeutic approach for these leukemia. Towards this, we selected a naïve antibody phage display library on both recombinant FLT3 receptor protein and FLT3-expressing leukemia cells using a tailored selection scheme that was designed to isolate antagonistic phage antibodies that not only interfere with receptor/ligand binding but also trigger receptor internalization upon cell surface binding. Phage antibodies were screened first for their ability to bind to cell surface receptor and induce receptor internalization, followed by their activity in blocking ligand-receptor interaction and neutralizing ligand-stimulated receptor activation and cell proliferation. We identified three fully human antibodies, EB10, A2IN, and D4-3, which bound specifically to both soluble and cell surface-expressed FLT3. All three antibodies were shown to be internalized upon binding to cell surface-expressed receptor in a time-dependent fashion. EB10 and D4-3 blocked ligand binding to the receptor with IC(50)s of 14 and 7 nM, respectively. Further, EB10 and D4-3 inhibited FLT3 ligand-induced receptor phosphorylation and cell proliferation in EOL-1 leukemia cells. Taken together, these results suggest that both EB10 and D4-3 may represent excellent therapeutic candidates for the treatment of FLT3-expressing human leukemia, both as unmodified antibodies and as conjugates of cytotoxic agents.
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237
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Lu D, Lamb CR, Patterson-Kane JC, Cappello R. Treatment of a prolapsed lumbar intervertebral disc in a ferret. J Small Anim Pract 2005; 45:501-3. [PMID: 15515799 DOI: 10.1111/j.1748-5827.2004.tb00195.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A seven-month-old, male ferret had acute paraplegia and radiographs showed signs of disc prolapse between the second and third lumbar vertebrae (L2/3). Hemilaminectomy was performed to decompress the spinal cord. Histological examination revealed that the extradural material was consistent with annulus fibrosus and the L2/3 articular facets were enlarged as a result of bone remodelling. The ferret became ambulatory one month postoperatively. Five months postoperatively, the ferret had normal posture with mild proprioceptive deficits in the pelvic limbs, and fusion of the L2 and L3 vertebral bodies.
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238
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Järbe TUC, DiPatrizio NV, Lu D, Makriyannis A. (???)-Adamantyl-??8-tetrahydrocannabinol (AM-411), a selective cannabinoid CB1 receptor agonist: effects on open-field behaviors and antagonism by SR-141716 in rats. Behav Pharmacol 2004; 15:517-21. [PMID: 15472574 DOI: 10.1097/00008877-200411000-00008] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
(-)-Adamantyl-Delta8-tetrahydrocannabinol (AM-411) is a 'classical' tricyclic cannabinoid CB1 receptor agonist in which the C-3 alkyl side-chain has been replaced with an adamantyl group. The compound is cannabinoid CB1 receptor subtype selective (CB1 Ki=6.86 nmol/l, CB2 Ki=52.0 nmol/l). We examined the effects of AM-411 alone and in combination with the cannabinoid CB1 receptor antagonist/inverse agonist, SR-141716, on open-field behaviors of rats. The lowest effective dose of AM-411, 3 mg/kg, suppressed ambulation (horizontal activity) and rearing (vertical activity) and increased circling frequency compared to vehicle control levels. Co-administration of SR-141716 normalized these changes. SR-141716 (3 and 5.6 mg/kg) also produced significant increases in scratching and grooming (both frequency and duration), effects that were not eliminated in the presence of AM-411. Coupled with previous drug discrimination data, the open-field profile of AM-411 suggests that this high-affinity CB1 cannabinoid receptor agonist induces behavioral effects similar to the natural cannabinoid Delta9-tetrahydrocannabinol and different from (R)-methanandamide, a chiral analog of the endogenous ligand anandamide.
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239
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Cherubini GB, Cappello R, Lu D, Targett M, Wessmann A, Mantis P. MRI findings in a dog with discospondylitis caused by Bordetella species. J Small Anim Pract 2004; 45:417-20. [PMID: 15352413 DOI: 10.1111/j.1748-5827.2004.tb00259.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A case of discospondylitis in a dog secondary to Bordetella species, diagnosed early with the assistance of magnetic resonance imaging (MRI), is reported. The history and clinical signs were suggestive of possible discospondylitis. MRI identified changes and allowed a presumptive diagnosis of discospondylitis, which was subsequently confirmed by bacterial culture of biopsy material. Discospondylitis associated with Bordetella species infection has not, to the authors' knowledge, been previously reported in the dog.
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240
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Owen MC, Lamb CR, Lu D, Targett MP. Material in the middle ear of dogs having magnetic resonance imaging for investigation of neurologic signs. Vet Radiol Ultrasound 2004; 45:149-55. [PMID: 15072148 DOI: 10.1111/j.1740-8261.2004.04025.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
The aim of this study was to determine the prevalence and potential significance of finding material in the middle ear of dogs having magnetic resonance (MR) imaging. Of 466 MR studies reviewed, an increased signal was identified in the tympanic bulla in 32 (7%) dogs. Cavalier King Charles spaniels, Cocker spaniels, Bulldogs, and Boxers were over-represented compared to the population of dogs having MR imaging. Five (16%) dogs had definite otitis media and one (3%) had a meningioma invading the middle ear. Of the remaining dogs, 13 (41%) had possible otitis media and 13 (41%) had neurologic conditions apparently unrelated to otitis media. The most common appearance of material in the middle ear was isointense in T1-weighted images and hyperintense in T2-weighted images. There was no apparent correlation between the signal characteristics of the material and the diagnosis. Enhanced signal after gadolinium administration was observed affecting the lining of the bulla in dogs with otitis media and in dogs with unrelated neurologic conditions. In dogs without clinical signs of otitis media, finding an increased signal in the middle ear during MR imaging may reflect subclinical otitis media or fluid accumulation unrelated to inflammation. Brachycephalic dogs may be predisposed to this condition.
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241
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Crawford S, Lu D, Maher JF. 303 CHARACTERIZATION OF EXPRESSION PATTERNS OF THE MOUSE FEM1C GENE. J Investig Med 2004. [DOI: 10.1136/jim-52-suppl1-856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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242
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Perrotti LI, Lu D, Niyomachai T, Cornejo S, Russo SJ, Jenab S, Quiñones-Jenab V. Temporal effects of estrogen and progesterone on behavioral and endocrinological responses to acute cocaine administration. Cell Mol Biol (Noisy-le-grand) 2003; 49:1269-74. [PMID: 14983997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/29/2023]
Abstract
Estrogen and progesterone have been postulated to play a key role modulating cocaine-induced behavioral and neurochemical activation in female rats. This study investigated the temporal relationship between estrogen and progesterone in the modulation of cocaine-induced behavioral alterations. Ovariectomized Fischer rats received s.c. injections of estradiol benzoate 48 hr prior to cocaine or saline treatment and one s.c. injection of progesterone concurrently or 1, 4, 20, 24, 30, 44 or 48 hr after estrogen treatment. Forty-eight hours after estrogen treatment rats received either a single i.p. injection of 15 mg/kg of cocaine or 0.9% saline. Overall, cocaine induced increases in locomotor behaviors (ambulatory and rearing activity). A bimodal interaction between estrogen and progesterone was observed in the modulation of all locomotor activities. A gradual increase in behaviors, which peaked when progesterone was administered 24 hr after estrogen was followed by an inhibition of both ambulatory and rearing activity when progesterone was administered for a shorter period of time. This estrogen and progesterone interaction was not observed in the modulation of cocaine-induced stereotypic activity. However, shorter administration of progesterone in relation to estrogen administration resulted in lowered benzoylecgonine plasma levels when compared to longer progesterone administration times. On the other hand, longer administration of progesterone (48 hr of estrogen and progesterone) caused increases in corticosterone levels in cocaine-treated rats. Thus, the temporal interaction between estrogen and progesterone in the regulation of cocaine metabolism and hypothalamic-pituitary-axis (HPA) activation do not completely correlate with that observed for locomotor behavioral activation. Taken together, these results suggest that temporal interactions between estrogen and progesterone may underlie some of the previously reported estrous cycle and sex effects on cocaine-induced behavioral and endocrinological alteration.
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243
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Lu D, Lamb CR, Pfeiffer DU, Targett MP. Neurological signs and results of magnetic resonance imaging in 40 cavalier King Charles spaniels with Chiari type 1-like malformations. Vet Rec 2003; 153:260-3. [PMID: 12974337 DOI: 10.1136/vr.153.9.260] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
In human beings a Chiari type 1 malformation is a developmental condition characterised by cerebellar herniation and syringohydromyelia. Abnormalities compatible with such a malformation were identified by magnetic resonance imaging in 39 cavalier King Charles spaniels with neurological signs and in one neurologically normal cavalier King Charles spaniel that was examined postmortem. The dogs with these abnormalities had a wide variety of neurological signs, but there was no apparent correlation between the neurological signs and the severity of cerebellar herniation, syringohydromyelia or hydrocephalus.
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Zhao D, Huang Y, Jin Z, Qu W, Lu D. Effect of aggregate size in cell cultures of Saussurea medusa on cell growth and jaceosidin production. PLANT CELL REPORTS 2003; 21:1129-1133. [PMID: 12836008 DOI: 10.1007/s00299-003-0631-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2002] [Revised: 03/10/2003] [Accepted: 03/11/2003] [Indexed: 05/24/2023]
Abstract
Cell suspension cultures of Saussurea medusa were grown in shake flasks and a 5-l stirred tank bioreactor. Biomass and jaceosidin distribution in cell aggregates of different sizes were investigated during the cultivation period. The results showed that on day 10, jaceosidin accumulation showed an increase with increasing size of the cell aggregate to 4 mm in diameter, with the highest jaceosidin accumulation being 12.2 mg/g. An inverse tendency was observed with cell aggregates larger than 4 mm in diameter, with the lowest accumulation being 3.1 mg/g. However, all of the cell aggregates, despite their size, synthesized almost the same amount of jaceosidin at day 12. Oxygen diffusion limitation and cell-cell contact may explain this behavior. In comparison with cells cultivated in shake flasks, decreased biomass and decreased jaceosidin concentration were observed when the cells were cultivated in a stirred tank bioreactor. The sublytic effects caused by the hydrodynamic stress in combination with insufficient nutrients in the bioreactor may cause cell damage.
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245
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Lu D, Pocknell A, Lamb CR, Targett MP. Concurrent benign and malignant multiple meningiomas in a cat: clinical, MRI and pathological findings. Vet Rec 2003; 152:780-2. [PMID: 12846291 DOI: 10.1136/vr.152.25.780] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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246
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Lu X, Lu D, Scully MF, Kakkar VV. Modulation of Integrin-binding Selectivity by Mutation within the RGDLoop of Snake Venom Proteins: A Novel Drug Development Approach. ACTA ACUST UNITED AC 2003; 1:189-96. [PMID: 15320698 DOI: 10.2174/1568016033477522] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Integrins are a family of heterodimeric class I transmembrane receptors, many of which bind to the RGD sequence in adhesive proteins and mediate the adhesive interactions of a variety of cells. The RGD motif has also been found in snake venom proteins that specifically inhibit integrin binding function and serve as potent integrin antagonists. The majority of these proteins interact with beta1 and beta3 associated integrins and their potency is at least 500-2000 times higher than short RGD peptides. Structural and functional studies suggest that the inhibitory potency of these proteins lies in subtle positional requirements of the tripeptide RGD that is harboured in a defined flexible loop. The integrin-binding specificity and selectivity of each of the proteins is controlled by amino acid residues in this loop in close vicinity to the RGD-motif. The review includes an overview of the structure and function of snake-venom integrin antagonists. The ability of these proteins to control platelet aggregation, cell adhesion and ligand binding is compared to that of short linear, cyclic RGD-peptides and RGD-containing proteins and the influence of modulation of amino acid residues flanking the RGD motif is also considered. The review is intended to provide insight into the development of novel inhibitors as drugs.
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Zhang R, Chen K, Lu D, Ma X, Hou L, Zhu X, Peng K, Wang T. [Study on efficacy of "bushen huoxue liquid" in male rats with osteoporosis induced by dexamethasone and its mechanism]. ZHONG YAO CAI = ZHONGYAOCAI = JOURNAL OF CHINESE MEDICINAL MATERIALS 2003; 26:347-9. [PMID: 14535018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/27/2023]
Abstract
OBJECTIVE To study the efficacy of "Bushen Huoxue Liquid" (BSHXL) in male rats with osteoporosis induced by dexamethasone (DM) and its mechanism. METHODS Forty-six male Sprague-Dawley rats at 18 months of age were chosen. They were divided into four groups, BSHXL and DM were administered appropriately for 12 weeks. General bone mineral density (GBMD), femur bending strength (FBS), serum-BGP, serum-PTH and serum-E2 were measured. RESULTS GBMD, FBS in BSHXL prevention group were significantly higher than those in DM group (P < 0.01), and the same with those in normal control group (P > 0.05). GBMD, FBS in BSHXL treatment group were higher than those in DM group (P < 0.05), and lower than those in normal control group. Compared with DM group, level of serum-T in BSHXL prevention group and BSHXL treatment group increased (P < 0.05) and level of serum-PTH in those two groups decreased (P < 0.05). But in comparison with DM group, level of serum-E2 and serum-BGP in the above-mentioned two groups had no significant difference (P > 0.05). CONCLUSION BSHXL could prevent and treat osteoporosis in male rats induced by DM.
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Zhu Z, Hattori K, Zhang H, Jimenez X, Ludwig DL, Dias S, Kussie P, Koo H, Kim HJ, Lu D, Liu M, Tejada R, Friedrich M, Bohlen P, Witte L, Rafii S. Inhibition of human leukemia in an animal model with human antibodies directed against vascular endothelial growth factor receptor 2. Correlation between antibody affinity and biological activity. Leukemia 2003; 17:604-11. [PMID: 12646950 DOI: 10.1038/sj.leu.2402831] [Citation(s) in RCA: 117] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Vascular endothelial growth factor (VEGF) and its receptors (VEGFR) have been implicated in promoting solid tumor growth and metastasis via stimulating tumor-associated angiogenesis. We recently showed that certain 'liquid' tumors such as leukemia not only produce VEGF, but also express functional VEGFR, resulting in an autocrine loop for tumor growth and propagation. A chimeric anti-VEGFR2 (or kinase insert domain-containing receptor, KDR) antibody, IMC-1C11, was shown to be able to inhibit VEGF-induced proliferation of human leukemia cells in vitro, and to prolong survival of nonobese diabetic-severe combined immune deficient (NOD-SCID) mice inoculated with human leukemia cells. Here we produced two fully human anti-KDR antibodies (IgG1), IMC-2C6 and IMC-1121, from Fab fragments originally isolated from a large antibody phage display library. These antibodies bind specifically to KDR with high affinities: 50 and 200 pM for IMC-1121 and IMC-2C6, respectively, as compared to 270 pM for IMC-1C11. Like IMC-1C11, both human antibodies block VEGF/KDR interaction with an IC(50) of approximately 1 nM, but IMC-1121 is a more potent inhibitor to VEGF-stimulated proliferation of human endothelial cells. These anti-KDR antibodies strongly inhibited VEGF-induced migration of human leukemia cells in vitro, and when administered in vivo, significantly prolonged survival of NOD-SCID mice inoculated with human leukemia cells. It is noteworthy that the mice treated with antibody of the highest affinity, IMC-1121, survived the longest period of time, followed by mice treated with IMC-2C6 and IMC-1C11. Taken together, our data suggest that anti-KDR antibodies may have broad applications in the treatment of both solid tumors and leukemia. It further underscores the efforts to identify antibodies of high affinity for enhanced antiangiogenic and antitumor activities.
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Wang Q, He P, Lu D, Shen A, Jiang N. Screening of pyruvate-producing yeast and effect of nutritional conditions on pyruvate production. Lett Appl Microbiol 2002; 35:338-42. [PMID: 12358699 DOI: 10.1046/j.1472-765x.2002.01188.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
AIMS To find a yeast strain that can overproduce pyruvate and to investigate the effect of nutrients on pyruvate production. METHODS AND RESULTS Trichosporon cutaneum PD70, a yeast strain that can overproduce pyruvate, was isolated from shake-flask cultures of 132 yeast strains. Pyruvate was measured by the HPLC or DNP method (see Materials and methods). Pyruvate production reached approximately 30.0 +/- 1.0 g l(-1) in basal fermentation medium. Different nutrient supplements had great effects on pyruvate production. Some of the conditions that gave the highest yield are described. CONCLUSIONS Exogenous thiamine supplement caused a decrease in pyruvate yield. Some amino acids, such as L-arginine, L-isoleucine and L-valine, caused a minor increase in pyruvate yield. Soybean peptone was the most suitable nitrogen source for pyruvate production. A glucose concentration of 15% in fermentation medium gave the highest yield (34.6 g l(-1)) and the highest yield against consumed glucose (0.429 g g(-1)). SIGNIFICANCE AND IMPACT OF THE STUDY Nutrients have significant impacts on pyruvate production. As a pyruvate overproducing yeast strain independent of exogenous vitamins or amino acids, T. cutaneum PD70 provides an advantage for commercial pyruvate production.
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Zhang W, Lu D, Kawazu S, Komeda K, Takeuchi T. Adenoviral insulin gene therapy prolongs survival of IDDM model BB rats by improving hyperlipidemia. Horm Metab Res 2002; 34:577-82. [PMID: 12439786 DOI: 10.1055/s-2002-35419] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Diabetes is frequently associated with hyperlipidemia, which results in atherogenic complications. Insulin-dependent diabetes mellitus (IDDM) model BB/Wor//Tky (BB) rats exhibit both hyperglycemia and hyperlipidemia and die within 3 weeks after the onset of diabetes unless insulin therapy is given. We performed insulin gene therapy in BB rats with adenovirus vectors through the tail vein. After infusion, plasma triglyceride levels dropped quickly and maintained low levels for 1 week, whereas blood glucose levels showed a slight decrease. The survival period of diabetic BB rats was prolonged to up to 75 days by infusing insulin gene-expressing adenoviral vectors. We suggest that the control of hyperlipidemia can be a life-saving measure when combined with hyperglycemia control in the treatment of diabetes.
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