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Ubhayakar GN, Li WY, Corbishley CM, Patel U. Improving glandular coverage during prostate biopsy using a long-core needle: technical performance of an end-cutting needle. BJU Int 2002; 89:40-3. [PMID: 11849158 DOI: 10.1046/j.1464-4096.2001.001177.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To compare the technical performance of a 33-mm core-length biopsy needle with that of the standard 18 mm needle, as many prostate cancers are isoechoic and in large prostates the tissue coverage with the 18 mm needle is inadequate. PATIENTS AND METHODS A 33-mm core length BioPince VSL disposable needle (Amedic, Sweden) and a standard TruCut 18 mm needle (Medical Device Technology Inc., FL, USA) were used to take prostatic biopsies in two groups of 15 patients. The following variables were assessed for each group: mean core length, core quality, capsular coverage (one or both capsules within the specimen), and side-effects in the first week after biopsy (for the BioPince group, surveyed using a self-completed questionnaire). The results were compared with historical data from a group of 30 patients biopsied using the standard needle. RESULTS For the BioPince and standard groups the mean (sd) core length was 19.4 (8.9) and 14.9 (5.1) mm, respectively. Four needles in the BioPince group failed to capture a sample, requiring needle replacement. The samples were fragmented in 15 of 90 (17%) and 41 of 90 (46%) biopsies in the BioPince and standard groups, respectively (P < 0.05). Specimens had both capsules present in five of 90 (6%) and four of 90 (4%), respectively. Within 7 days minor bleeding was the most common side-effect. Pain after biopsy was the only symptom showing a significant difference between the groups, at six of 15 and none (P = 0.001), respectively. The incidence of haematuria, haematospermia and rectal bleeding was similar in the two groups (P > 0.05), but fever more common (three vs none) in the BioPince group (P = 0.06). CONCLUSION When set at a 33-mm stroke length, the BioPince needle increases the mean core length by 30%, with less fragmentation than a standard 18 mm needle. However, it has a significant failure rate for capture (27% needle replacement rate), slightly greater morbidity (pain and possibly fever) and shows no advantage in capsular coverage. Therefore, there are shortcomings with this end-cutting needle when used at 33 mm core length.
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Patel U, Yan YP, Hobbs FW, Kaczmarczyk J, Slee AM, Pompliano DL, Kurilla MG, Bobkova EV. Oxazolidinones mechanism of action: inhibition of the first peptide bond formation. J Biol Chem 2001; 276:37199-205. [PMID: 11483595 DOI: 10.1074/jbc.m102966200] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Oxazolidinones are potent inhibitors of bacterial protein biosynthesis. Previous studies have demonstrated that this new class of antimicrobial agent blocks translation by inhibiting initiation complex formation, while post-initiation translation by polysomes and poly(U)-dependent translation is not a target for these compounds. We found that oxazolidinones inhibit translation of natural mRNA templates but have no significant effect on poly(A)-dependent translation. Here we show that various oxazolidinones inhibit ribosomal peptidyltransferase activity in the simple reaction of 70 S ribosomes using initiator-tRNA or N-protected CCA-Phe as a P-site substrate and puromycin as an A-site substrate. Steady-state kinetic analysis shows that oxazolidinones display a competitive inhibition pattern with respect to both the P-site and A-site substrates. This is consistent with a rapid equilibrium, ordered mechanism of the peptidyltransferase reaction, wherein binding of the A-site substrate can occur only after complex formation between peptidyltransferase and the P-site substrate. We propose that oxazolidinones inhibit bacterial protein biosynthesis by interfering with the binding of initiator fMet-tRNA(i)(Met) to the ribosomal peptidyltransferase P-site, which is vacant only prior to the formation of the first peptide bond.
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Seymour H, Perry MJ, Lee-Elliot C, Dundas D, Patel U. Pain after transrectal ultrasonography-guided prostate biopsy: the advantages of periprostatic local anaesthesia. BJU Int 2001; 88:540-4. [PMID: 11678747 DOI: 10.1046/j.1464-410x.2001.02324.x] [Citation(s) in RCA: 88] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
OBJECTIVE To prospectively evaluate the efficacy and safety of periprostatic local anaesthesia (LA) during prostatic biopsy guided by transrectal ultrasonography (TRUS), as 20-65% of men report moderate to severe pain, and there is anecdotal and published evidence that periprostatic anaesthesia improves patients' tolerance. PATIENTS AND METHODS In all, 157 patients were prospectively recruited and sequentially randomized to receive either LA or no anaesthesia. Sextant biopsies were taken in all men but some had more than six biopsies. All were asked to complete questionnaires immediately after TRUS-guided biopsy and for the subsequent week, giving pain scores and recording any morbidity, including symptoms of infection; analgesic use was also surveyed. RESULTS Patients given LA had significantly lower pain scores at the time of biopsy than those given no anaesthesia, with median (sd) pain scores of 1.53 (0.7) and 1.95 (0.65) (P < 0.001), respectively. In addition, there was a trend towards less analgesic use by those given LA, although this was not statistically significant. There was no difference in the amount of haematuria, haematochezia or haematospermia, or infection rate, between the groups. The additional cost and time of the procedure was minimal ( pound3.00 and 3 min/per patient, respectively). CONCLUSION Periprostatic LA infiltration is a quick and simple procedure which significantly improves immediate pain with no added morbidity; we strongly advocate its use to improve patient tolerance of TRUS-guided prostate biopsy.
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Viswanathan K, Daniak SM, Salomone K, Kiely T, Patel U, Converso K, Manning WJ, Silverman DI. Effect of cardioversion of atrial fibrillation on improvement in left ventricular performance. Am J Cardiol 2001; 88:439-41. [PMID: 11545774 DOI: 10.1016/s0002-9149(01)01699-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Kariv I, Cao H, Marvil PD, Bobkova EV, Bukhtiyarov YE, Yan YP, Patel U, Coudurier L, Chung TD, Oldenburg KR. Identification of inhibitors of bacterial transcription/translation machinery utilizing a miniaturized 1536-well format screen. JOURNAL OF BIOMOLECULAR SCREENING 2001; 6:233-43. [PMID: 11689123 DOI: 10.1177/108705710100600405] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
This report presents the miniaturization of a HTS screen to identify inhibitors of prokaryotic transcription-translation in a 1536-well format. The in vitro assay design utilized the bacterial expression machinery to drive expression of a firefly luciferase reporter gene, which was read as an endpoint luminesence measurement. This multicomponent system permits identification of inhibitors at different steps in this pathway. Successful miniaturization required integration of homogeneous assay formats, robust liquid-handling workstations, and second-generation imaging systems. Comparison of data from a triplicate 1536-well screen of a subset of a target library that had been previously validated and followed up for hit confirmation in a 384-well plate format confirmed that triplicate screening yields data of higher confidence and quality, eliminates the time-consuming and potentially error-prone step of cherry-picking, and reduces the number of false positives and negatives. The substantial savings of reagents and reduction of the numbers of plates to process obtained in a 1536-well format as compared to a 384-well format allowed a full triplicate evaluation of the entire library of 183,000 compounds at lower cost and in less time. The triplicate-screen statistics are consistent with a highly reliable data set with a coefficient of variation of 14.8% and Z' and Z values of 0.57 and 0.25, respectively. This screen resulted in the identification of 1,149 hits (0.63% hit rate), representing a compound population at 2.5 standard deviations from the mean cutoff. Furthermore, the data demonstrate good agreement between IC(50) values derived for this assay in a 1536-well format and 384-well format.
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Watson GM, Patel U. Primary antegrade ureteric stenting: prospective experience and cost-effectiveness analysis in 50 ureters. Clin Radiol 2001; 56:568-74. [PMID: 11446755 DOI: 10.1053/crad.2000.0708] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
AIM To evaluate the success rate and cost efficiency of primary antegrade ureteric stenting (antegrade ureteric stent insertion as a single procedure without preliminary drainage). MATERIALS AND METHODS A policy of primary stenting was tested in 38 patients (50 ureters) with obstructive hydronephrosis, of acute or chronic onset and of benign or malignant origin. Patients with suspected pyonephrosis were excluded. Patients successfully primarily stented (group 1) were compared to a group stented as a traditional two-stage procedure (group 2). End point assessments were screening time, equipment used, procedure-related costs, bed occupancy and technical and clinical success rate. Using these cost and outcome measures, a cost-efficiency analysis was performed comparing the two strategies. RESULTS 40/50 (80%) ureters were considered primary stent successes. The average procedure-related bed occupancy was 2 days (range 1-2 days). Simple equipment alone was successful in 16 cases. Van ( pound46/case). The mean screening time was similar for the two groups (13.5 min vs Andel dilatation catheters and peel-away sheaths were frequently used (23 ureters). Expensive equipment was rarely necessary (four cases) and average extra equipment cost was small 15.3 min; P > or = 0.05). There was a minimum saving of pound800 per successful primary stent. The cost-effectiveness of a primary antegrade stenting strategy was pound1229 vs pound2093 for secondary stenting. CONCLUSION In carefully selected patients, the majority of obstructed ureters can be primarily stented using simple equipment. The reduced hospital stay and overall success rate significantly improves the cost competitiveness of antegrade ureteric stenting.
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Weigner MJ, Thomas LR, Patel U, Schwartz JG, Burger AJ, Douglas PS, Silverman DI, Manning WJ. Early cardioversion of atrial fibrillation facilitated by transesophageal echocardiography: short-term safety and impact on maintenance of sinus rhythm at 1 year. Am J Med 2001; 110:694-702. [PMID: 11403753 DOI: 10.1016/s0002-9343(01)00716-1] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
BACKGROUND For patients presenting with atrial fibrillation of only a few weeks duration, the use of transesophageal echocardiography offers the opportunity to markedly abbreviate the duration of atrial fibrillation before cardioversion. We sought to determine if the shorter duration of atrial fibrillation allowed by a transesophageal echocardiography strategy had an impact on the recurrence of atrial fibrillation and prevalence of sinus rhythm during the first year following cardioversion. METHODS Transesophageal echocardiography was attempted in 539 patients (292 men, 247 women; 71.6 +/- 13.0 years.) with atrial fibrillation > or =2 days (66.1% <3 weeks) or of unknown duration before elective cardioversion of atrial fibrillation. Therapeutic anticoagulation at the time of transesophageal echocardiography was present in 94.6% of patients, and 73.4% of subjects were discharged on warfarin. RESULTS Atrial thrombi were identified in 70 (13.1%) patients. Successful cardioversion in 413 patients without evidence of atrial thrombi was associated with clinical thromboembolism in 1 patient (0.24%, 95% confidence interval: 0.0--0.8%). In patients with atrial fibrillation <3 weeks at the time of cardioversion (a duration incompatible with conventional therapy of 3 to 4 weeks of warfarin before cardioversion), the 1-year atrial fibrillation recurrence rate was lower (41.1% vs. 57.9%, P <0.01), and the prevalence of sinus rhythm at 1 year was increased (65.8% vs. 51.3%, P <0.03). No other clinical or echocardiographic index was associated with recurrence of atrial fibrillation or sinus rhythm at 1 year. CONCLUSIONS Early cardioversion facilitated by transesophageal echocardiography has a favorable safety profile and provides the associated benefit of reduced recurrence of atrial fibrillation for patients in whom the duration of atrial fibrillation is <3 weeks.
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Bhattacharyya N, Banerjee T, Patel U, Banerjee S. Impaired repair activity of a truncated DNA polymerase beta protein. Life Sci 2001; 69:271-80. [PMID: 11441918 DOI: 10.1016/s0024-3205(01)01120-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
DNA polymerase beta (polbeta) is an essential enzyme for gap filling synthesis in damaged DNA template involved in base excision repair pathway. A truncated polbeta protein is expressed in primary colorectal and breast adenocarcinomas. To determine a possible alteration in the functions of the enzyme, a human cell line named HeLapolbetadelta expressing the truncated form of polbeta has been established. These cells revealed a significantly reduced level of repair activity evaluated by gap filling synthesis and polbeta activity. More importantly, the HeLapolbetadelta cells are hypersensitive to MNNG, a DNA alkylating agent. It appears from the responses that the gap filling synthesis of WT cells, a HeLa cell line overexpressing wild-type polbeta protein, was inhibited by HeLapolbetadelta protein.
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Patel U. Foreign body aspiration: An unusual presentation of myasthenia gravis. Otolaryngol Head Neck Surg 2001. [DOI: 10.1067/mhn.2001.115766] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Patel U, Forsen J. Foreign body aspiration: an unusual presentation of myasthenia gravis. Otolaryngol Head Neck Surg 2001; 124:698-9. [PMID: 11391268 DOI: 10.1177/019459980112400623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Seymour HR, Matson MB, Belli AM, Morgan R, Kyriou J, Patel U. Rotational digital subtraction angiography of the renal arteries: technique and evaluation in the study of native and transplant renal arteries. Br J Radiol 2001; 74:134-41. [PMID: 11718384 DOI: 10.1259/bjr.74.878.740134] [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: 11/05/2022] Open
Abstract
Rotational digital subtraction angiography (RDSA) allows multidirectional angiographic acquisitions with a single injection of contrast medium. The role of RDSA was evaluated in 60 patients referred over a 7-month period for diagnostic renal angiography and 12 patients referred for renal transplant studies. All angiograms were assessed for their diagnostic value, the presence of anomalies and the quantity of contrast medium used. The effective dose for native renal RDSA was determined. 41 (68.3%) native renal RDSA images and 8 (66.7%) transplant renal RDSA images were of diagnostic quality. Multiple renal arteries were identified in 9/41 (22%) native renal RDSA diagnostic images. The mean volume of contrast medium in the RDSA runs was 51.2 ml and 50 ml for native and transplant renal studies, respectively. The mean effective dose for 120 degrees native renal RDSA was 2.36 mSv, equivalent to 1 year's mean background radiation. Those RDSA images that were non-diagnostic allowed accurate prediction of the optimal angle for further static angiographic series, which is of great value in transplant renal vessels.
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LaPoint SF, Patel U, Rubio A. Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL). Adv Anat Pathol 2000; 7:307-21. [PMID: 10976909 DOI: 10.1097/00125480-200007050-00004] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a recently described neurovascular disease affecting young to middle age individuals. The disease is caused by mutations in the Notch3 gene located in the short arm of chromosome 19. Clinically, the disease is characterized by migrainous headaches (with or without aura), mood disturbances, focal neurologic deficits, transient ischemic attacks, strokes, and dementia. Pathologically, the disease is characterized by a stereotypic degeneration of the arterial walls (especially in the intracranial compartments) with deposition in the media of a nonatheromatous, nonamyloidotic substance that under the electron microscope (EM) appears as a granular osmiophilic material (GOM), pathognomonic for the disease. The nature of the GOM is undetermined and the pathogenesis remains to be elucidated. A review of current literature in English language is presented on the clinical, radiologic, pathologic, and genetic features of CADASIL.
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Lee-Elliott C, Khaw KT, Belli AM, Patel U. Iatrogenic arteriovenous fistula in a renal allograft: the result of a TAD guidewire injury. Cardiovasc Intervent Radiol 2000; 23:306-9. [PMID: 10960547 DOI: 10.1007/s002700010075] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
A case is presented of an iatrogenic arteriovenous fistula developing in a renal allograft following guidewire manipulation during transplant renal artery angioplasty. Hyperdynamic flow through the fistula was causing a shunt of blood away from the renal cortex as demonstrated on sonography and scintigraphy. Selective embolization was performed, correcting the maldistribution of flow to the peripheral renal cortex. The diagnosis and difficulty in management of asymptomatic renal arteriovenous fistulae is also discussed.
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Whitson BA, Cheng BC, Kokini K, Badylak SF, Patel U, Morff R, O'Keefe CR. Multilaminate resorbable biomedical device under biaxial loading. JOURNAL OF BIOMEDICAL MATERIALS RESEARCH 2000; 43:277-81. [PMID: 9730065 DOI: 10.1002/(sici)1097-4636(199823)43:3<277::aid-jbm8>3.0.co;2-k] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The design and test of a multilaminate sheet developed for a hernia repair application is presented. As biomaterial applications become more complex, characterization of uniaxial properties becomes insufficient and biaxial testing becomes necessary. A measure of the in-plane biaxial strength of the device is inferred from a ball burst test. The results of this test for different thicknesses of the device are correlated with the uniaxial strength of the material. A biaxial test such as the ball burst test is more indicative of the properties of a planar material than would be a uniaxial test. The interactions in the biaxial mode of failure are of value and can be related back to a classical uniaxial tensile test from the ball burst test. The material used in this study to fabricate the device was a resorbable biomaterial called small intestinal submucosa (SIS). The effects of rehydration on the stiffness and associated ball burst properties of the SIS device were also measured. It is shown that at a rehydration time of 5 min from a reference dry state, steady-state mechanical properties are reached.
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Abou-Gharbia MA, Childers WE, Fletcher H, McGaughey G, Patel U, Webb MB, Yardley J, Andree T, Boast C, Kucharik RJ, Marquis K, Morris H, Scerni R, Moyer JA. Synthesis and SAR of adatanserin: novel adamantyl aryl- and heteroarylpiperazines with dual serotonin 5-HT(1A) and 5-HT(2) activity as potential anxiolytic and antidepressant agents. J Med Chem 1999; 42:5077-94. [PMID: 10602693 DOI: 10.1021/jm9806704] [Citation(s) in RCA: 72] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Several novel functionalized adamantyl aryl- and heteroarylpiperazine derivatives were prepared and examined in various receptor binding and behavioral tests to determine their serotonin receptor activities. Many compounds demonstrated modest to high affinity for 5-HT(1A) receptors, with compounds 9, 13, 23, 33, 34, and 43 being the most potent at this site. Compound 1, 2-[4-(2-pyrimidinyl)-1-piperazinyl]ethyl adamantyl-1-carboxylate, demonstrated relatively high affinity for 5-HT(1A) receptors (K(i) = 8 nM) and acceptable selectivity versus D(2) receptors (K(i) = 708 mM); however, it lacked in vivo activity in serotonergic behavioral models. In contrast, compounds 9 (WY-50,324, SEB-324, adatanserin), adamantyl-1-carboxylic acid 2-[4-(2-pyrimidinyl)-1-piperazinyl]ethylamide, and 13, adamantyl-1-carboxylic acid 2-[4-(2-methoxyphenyl)-1-piperazinyl]ethylamide, demonstrated high affinity for 5-HT(1A) binding sites (K(i) = 1 nM for both) and moderate affinity for 5-HT(2) receptors (K(i) = 73 and 75 nM, respectively). Both compounds also demonstrated partial 5-HT(1A) agonist activity in vivo in rat serotonin syndrome and 5-HT(2) antagonist activity in quipazine- and DOI-induced head shake paradigms. The selective 5-HT(1A) partial agonist and 5-HT(2) antagonist activity of 9 was accompanied by significant anxiolytic activity in an animal conflict model. On the basis of this profile, compound 9 entered development as a combined anxiolytic and antidepressant agent.
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Shah J, Jones J, Miller MA, Patel U, Anson KM. Selective embolization of bleeding renal angiomyolipoma in pregnancy. J R Soc Med 1999; 92:414-5. [PMID: 10656013 PMCID: PMC1297323 DOI: 10.1177/014107689909200813] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Beaulieu PL, Cameron DR, Ferland JM, Gauthier J, Ghiro E, Gillard J, Gorys V, Poirier M, Rancourt J, Wernic D, Llinas-Brunet M, Betageri R, Cardozo M, Hickey ER, Ingraham R, Jakes S, Kabcenell A, Kirrane T, Lukas S, Patel U, Proudfoot J, Sharma R, Tong L, Moss N. Ligands for the tyrosine kinase p56lck SH2 domain: discovery of potent dipeptide derivatives with monocharged, nonhydrolyzable phosphate replacements. J Med Chem 1999; 42:1757-66. [PMID: 10346928 DOI: 10.1021/jm980676t] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
p56lck is a member of the src family of tyrosine kinases. Through modular binding units called SH2 domains, p56lck promotes phosphotyrosine-dependent protein-protein interactions and plays a critical role in signal transduction events that lead to T-cell activation. Starting from the phosphorylated dipeptide (2), a high-affinity ligand for the p56lck SH2 domain, we have designed novel dipeptides that contain monocharged, nonhydrolyzable phosphate group replacements and bind to the protein with KD's in the low micromolar range. Replacement of the phosphate group in phosphotyrosine-containing sequences by a (R/S)-hydroxyacetic (compound 8) or an oxamic acid (compound 10) moiety leads to hydrolytically stable, monocharged ligands, with 83- and 233-fold decreases in potency, respectively. This loss in binding affinity can be partially compensated for by incorporating large lipophilic groups at the inhibitor N-terminus. These groups provide up to 13-fold increases in potency depending on the nature of the phosphate replacement. The discovery of potent (2-3 microM), hydrolytically stable dipeptide derivatives, bearing only two charges at physiological pH, represents a significant step toward the discovery of compounds with cellular activity and the development of novel therapeutics for conditions associated with undesired T-cell proliferation.
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Jones J, Shah J, Morris S, Gordon EM, Patel U, Corbishley CM. An unusual renal mass after partial nephrectomy for renal cell carcinoma. J Urol 1999; 161:913-4. [PMID: 10022714] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
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Miki Y, Grossman RI, Udupa JK, van Buchem MA, Wei L, Phillips MD, Patel U, McGowan JC, Kolson DL. Differences between relapsing-remitting and chronic progressive multiple sclerosis as determined with quantitative MR imaging. Radiology 1999; 210:769-74. [PMID: 10207480 DOI: 10.1148/radiology.210.3.r99mr44769] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
PURPOSE To investigate the cross-sectional relationships among multiple quantitative brain magnetic resonance (MR) imaging measurements in patients with relapsing-remitting versus chronic progressive multiple sclerosis (MS). MATERIALS AND METHODS Thirty-eight patients with MS (relapsing-remitting, 26, chronic progressive, 12) were examined. Lesion volume on T2-weighted MR images, contrast material-enhancing lesion volume, percentage of brain parenchymal volume (brain volume/[brain volume + cerebrospinal fluid volume), and magnetization transfer ratio histogram peak height for the whole brain were calculated. RESULTS Significant negative correlation was noted between volume on T2-weighted images and magnetization transfer ratio histogram peak height for both the relapsing-remitting and chronic progressive groups (P < .001 for both). A positive correlation was demonstrated for lesion volume on T2-weighted images and enhancing lesion volume in the relapsing-remitting group (P < .01) but not in the chronic progressive group. Negative correlations were demonstrated for enhancing lesion volume and magnetization transfer ratio histogram peak height (P = .02), for Expanded Disability Status Scale score and magnetization transfer histogram peak height (P = .02), and for Expanded Disability Status Scale score and percentage of brain parenchymal volume in the relapsing-remitting group (P = .004) but not in the chronic progressive group. CONCLUSION The cross-sectional relationships among multiple quantitative brain MR imaging measurements are different between relapsing-remitting and chronic progressive MS.
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Llinaś-Brunet M, Beaulieu PL, Cameron DR, Ferland JM, Gauthier J, Ghiro E, Gillard J, Gorys V, Poirier M, Rancourt J, Wernic D, Betageri R, Cardozo M, Jakes S, Lukas S, Patel U, Proudfoot J, Moss N. Phosphotyrosine-containing dipeptides as high-affinity ligands for the p56lck SH2 domain. J Med Chem 1999; 42:722-9. [PMID: 10052978 DOI: 10.1021/jm980612i] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Src homology-2 (SH2) domains are noncatalytic motifs containing approximately 100 amino acid residues that are involved in intracellular signal transduction. The phosphotyrosine-containing tetrapeptide Ac-pYEEI binds to the SH2 domain of p56lck (Lck) with an affinity of 0.1 microM. Starting from Ac-pYEEI, we have designed potent antagonists of the Lck SH2 domain which are reduced in peptidic character and in which the three carboxyl groups have been eliminated. The two C-terminal amino acids (EI) have been replaced by benzylamine derivatives and the pY + 1 glutamic acid has been substituted with leucine. The best C-terminal fragment identified, (S)-1-(4-isopropylphenyl)ethylamine, binds to the Lck SH2 domain better than the C-terminal dipeptide EI. Molecular modeling suggests that the substituents at the 4-position of the phenyl ring occupy the pY + 3 lipophilic pocket in the SH2 domain originally occupied by the isoleucine side chain. This new series of phosphotyrosine-containing dipeptides binds to the Lck SH2 domain with potencies comparable to that of tetrapeptide 1.
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Yamada K, Patel U, Shrier DA, Tanaka H, Chang JK, Numaguchi Y. MR imaging of CNS tractopathy: wallerian and transneuronal degeneration. AJR Am J Roentgenol 1998; 171:813-8. [PMID: 9725322 DOI: 10.2214/ajr.171.3.9725322] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Ford JC, Hackney DB, Lavi E, Phillips M, Patel U. Dependence of apparent diffusion coefficients on axonal spacing, membrane permeability, and diffusion time in spinal cord white matter. J Magn Reson Imaging 1998; 8:775-82. [PMID: 9702877 DOI: 10.1002/jmri.1880080405] [Citation(s) in RCA: 73] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
We used a numerical simulation of water self-diffusion among permeable cylinders to predict the dependence of MR-based apparent diffusion coefficients in white matter on axonal separation, barrier permeability, and diffusion time (T). The transverse apparent diffusion coefficient (tADC), calculated with simulated diffusion-sensitizing gradients perpendicular to the axon fibers, remains a function of T down to diffusion times as short as .1 microsec for a range of diffusion barrier permeability. As the diffusion time lengthens, the response of tADC depends on axon diameter, with decreases in tADC occurring earliest, and most dramatically, for the smallest fiber diameter simulated (2 microm). For a given axonal separation, asymptotic values of ADC are determined by permeability alone and are the same for 2-microm and 11-microm fibers of equal membrane permeability. The effect of increased relative intracellular volume is manifested primarily in a decrease in tADC at short T. Increases in interaxonal spacing increase the tADC at asymptotically long diffusion times and reduce the dependence on permeability. However, at the widest plausible axonal separations, permeability remains an important determinant of tADC. These simulations may enhance interpretation of measured tADC in the context of the underlying physiologic and structural changes at the cellular level that accompany white-matter disease.
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Patel U. Amplatz gooseneck snare in stripping of failing haemodialysis catheters. Clin Radiol 1998; 53:541. [PMID: 9714402 DOI: 10.1016/s0009-9260(98)80183-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
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Patel U, Forte V, Taylor G, Sirkin W. Castleman's disease as a rare cause of a neck mass in a child. THE JOURNAL OF OTOLARYNGOLOGY 1998; 27:171-3. [PMID: 9664249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
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Yamada K, Shrier DA, Rubio A, Yoshiura T, Iwanaga S, Shibata DK, Patel U, Numaguchi Y. MR imaging of the mamillothalamic tract. Radiology 1998; 207:593-8. [PMID: 9609878 DOI: 10.1148/radiology.207.3.9609878] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
PURPOSE To demonstrate the normal and abnormal appearance of the mamillothalamic tract (MTT) on cranial magnetic resonance (MR) images. MATERIALS AND METHODS Two formalin-fixed normal human brain specimens sectioned in axial and coronal planes were used to demonstrate the normal anatomy of the MTT. MR images were obtained in 32 volunteers. Proton-density-weighted coronal and axial pulse sequences were used. The images were evaluated for visualization quality and size and signal intensity of the MTTs in correlation with the specimens. Abnormal MTTs were identified on cranial MR images in two patients, and the imaging findings were analyzed. The clinical history of the patients was also reviewed to determine the effect of these findings on patient care. RESULTS Normal MTTs were easily identified on MR studies of cadaveric brains and of the brains of the human volunteers. On MR images, normal MTTs were commonly symmetric in appearance, with signal intensity equal to that of other normal fiber tracts. The abnormal MTTs showed high signal intensity on images obtained with a long repetition time or asymmetric volume loss and were associated with atrophy of the ipsilateral mamillary body. CONCLUSION Normal MTTs are readily visible on conventional MR images. Abnormality of the MTT is a very subtle finding but may be a marker of a limbic system abnormality.
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