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Parthasarathy R, Cote GJ, Gagel RF. Hammerhead ribozyme-mediated inactivation of mutant RET in medullary thyroid carcinoma. Cancer Res 1999; 59:3911-4. [PMID: 10463581] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
Abstract
Activating mutations of the RET proto-oncogene cause hereditary medullary thyroid carcinoma. To examine whether selective inactivation of mutant RET could prevent transformation, a hammerhead ribozyme was designed to cleave RET mRNA containing a transforming mutation of codon 634 TGC --> TAC (Cys634Tyr). In vitro RNA cleavage assay demonstrated that the ribozyme selectively cleaved RET RNA with a Cys634Tyr but not Cys634Arg or the normal sequence. Expression of ribozyme in NIH/3T3 cells prevented RET-mediated colony formation in soft agar. This inhibition required catalytically active ribozyme and was specific for the TAC mutation. Therefore, ribozymes designed to selectively target mutant RET RNA may provide an effective therapeutic in the treatment of this syndrome.
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Parthasarathy R, Sriram K, Santha T, Prabhakar R, Somasundaram PR, Sivasubramanian S. Short-course chemotherapy for tuberculosis of the spine. ACTA ACUST UNITED AC 1999. [DOI: 10.1302/0301-620x.81b3.0810464] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
We performed a randomised, controlled clinical trial to compare ambulant short-course chemotherapy with anterior spinal fusion plus short-course chemotherapy for spinal tuberculosis without paraplegia. Patients with active disease of vertebral bodies were randomly allocated to one of three regimens: a) radical anterior resection with bone grafting plus six months of daily isoniazid plus rifampicin (Rad6); b) ambulant chemotherapy for six months with daily isoniazid plus rifampicin (Amb6); or c) similar to b) but with chemotherapy for nine months (Amb9). Ten years from the onset of treatment, 90% of 78 Rad6, 94% of 78 Amb6 and 99% of 79 Amb9 patients had a favourable status. Ambulant chemotherapy for a period of six months with daily isoniazid plus rifampicin (Amb6) was an effective treatment for spinal tuberculosis except in patients aged less than 15 years with an initial angle of kyphosis of more than 30° whose kyphosis increased substantially.
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Parthasarathy R, Sriram K, Santha T, Prabhakar R, Somasundaram PR, Sivasubramanian S. Short-course chemotherapy for tuberculosis of the spine. A comparison between ambulant treatment and radical surgery--ten-year report. THE JOURNAL OF BONE AND JOINT SURGERY. BRITISH VOLUME 1999; 81:464-71. [PMID: 10872368 DOI: 10.1302/0301-620x.81b3.9043] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
We performed a randomised, controlled clinical trial to compare ambulant short-course chemotherapy with anterior spinal fusion plus short-course chemotherapy for spinal tuberculosis without paraplegia. Patients with active disease of vertebral bodies were randomly allocated to one of three regimens: a) radical anterior resection with bone grafting plus six months of daily isoniazid plus rifampicin (Rad6); b) ambulant chemotherapy for six months with daily isoniazid plus rifampicin (Amb6); or c) similar to b) but with chemotherapy for nine months (Amb9). Ten years from the onset of treatment, 90% of 78 Rad6, 94% of 78 Amb6 and 99% of 79 Amb9 patients had a favourable status. Ambulant chemotherapy for a period of six months with daily isoniazid plus rifampicin (Amb6) was an effective treatment for spinal tuberculosis except in patients aged less than 15 years with an initial angle of kyphosis of more than 30 degrees whose kyphosis increased substantially.
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Parthasarathy R, Gilbert B, Mehta K. Aerosol delivery of liposomal all-trans-retinoic acid to the lungs. Cancer Chemother Pharmacol 1999; 43:277-83. [PMID: 10071977 DOI: 10.1007/s002800050895] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE To optimize the delivery of all-trans-retinoic acid (ATRA) to lung tissue, we determined the potential of vehiculating the drug in liposomes (L-ATRA) and delivering it via aerosol. Liposomes may provide a means to prevent local irritation of lung tissue and reduce pulmonary toxicity, prolong therapeutic levels and generate high drug concentrations at the tumor sites. Cumulatively, this would result in reduced systemic toxicity and enhanced drug efficacy. METHODS Previous studies have shown that liposomes can serve as excellent carriers for otherwise poorly soluble ATRA. Delivery of ATRA to the lung tissue of mice was accomplished by nebulization of L-ATRA. The liposomes in the aerosol were relatively uniform (309 +/- 138 nm), stable, and retained the drug well. RESULTS The drug was effectively delivered at high concentrations (10 +/- 2 microg/g of tissue) to the lungs of mice and was retained for at least up to 96 h after a single exposure to L-ATRA aerosol. No appreciable levels of ATRA were detected in the blood or the liver of treated mice. The aerosol-delivered ATRA was biologically active as demonstrated by its ability to induce the expression of tissue-type transglutaminase. CONCLUSION Aerosol delivery of L-ATRA offers an effective way to deliver high levels of ATRA to the lung without apparent pulmonary toxic effects.
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Parthasarathy R, Viswanathan KS. Self-dual Chern-Simons equations and Nambu-Goto action. ACTA ACUST UNITED AC 1999. [DOI: 10.1088/0305-4470/31/50/011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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106
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Parthasarathy R, Viswanathan KS. A q-analogue of the supersymmetric oscillator and its q-superalgebra. ACTA ACUST UNITED AC 1999. [DOI: 10.1088/0305-4470/24/3/019] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Abstract
Treatment with all-trans-retinoic acid (ATRA) induces complete remission in many acute promyelocytic leukemia patients. However, plasma drug levels progressively decrease following prolonged treatment with oral ATRA. This decrease is due, at least in part, to the induced cytochrome P-450-dependent metabolism of ATRA. To investigate if incorporation of ATRA in liposomes could alter its metabolism, we compared the cellular metabolism of liposomal-ATRA (L-ATRA) with free drug. Microsomes isolated from the rat liver metabolized L-ATRA to a significantly lower extent than they did free-ATRA. Similarly, in F9 cells, L-ATRA was metabolized at a slower rate than the free drug. These results suggest that L-ATRA may have important clinical implications in terms of slowing down the rate of ATRA metabolism and producing long-term remission in APL patients.
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Parthasarathy R, Finch CD, Wolfgang J, Nordlander P, Dunning FB. Low-energy dissociative electron attachment to CH2Br2, CHClBr2, and CCl3Br: Intermediate lifetimes and decay energetics. J Chem Phys 1998. [DOI: 10.1063/1.477553] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Kayasth S, Raje N, Asari T, Parthasarathy R. Trace element profile of semiconductor materials: Gallium and arsenic. Anal Chim Acta 1998. [DOI: 10.1016/s0003-2670(98)00267-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Vadnal R, Heng HH, Parthasarathy L, Parthasarathy R. Human chromosomal localization of a gene for inositol monophosphatase by fluorescence in situ hybridization. Neuroreport 1998; 9:683-5. [PMID: 9559938 DOI: 10.1097/00001756-199803090-00022] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Inhibition of the enzyme inositol monophosphatase (IMPase) (E.C. 3.1.3.25) has been linked to the therapeutic action of lithium in the treatment of manic-depression (bipolar) disorder. Because of the link between bipolar and IMPase, we felt it would be of considerable importance to determine the human chromosomal localization of the IMPase gene. Fluorescence in situ hybridization analysis using a human cDNA clone, which included the 5'-UTR and the complete coding region, mapped the human IMPase gene to chromosome 8q21.2-21.3. No gene locus for manic-depressive disorder has yet been identified. Further studies on this IMPase gene, and other potential gene variants and mutations, should help to determine if specific subgroups of patients with manic-depressive disorder can be determined on a molecular basis, with regard to the IMPase gene.
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Balakrishnan R, Parthasarathy R, Sulkowski E. Alzheimer's beta-amyloid peptide: affinity for metal chelates. THE JOURNAL OF PEPTIDE RESEARCH : OFFICIAL JOURNAL OF THE AMERICAN PEPTIDE SOCIETY 1998; 51:91-5. [PMID: 9516042 DOI: 10.1111/j.1399-3011.1998.tb00624.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Alzheimer's amyloid peptide, A beta(1-42) and its fragments, A beta(1-28) and A beta(1-16), were chromatographed on IDA-M(II) columns (M: Cu2+, Ni2+ and Zn2+). The retention of A beta(1-42) and its fragments on IDA-Cu(II) could not be reversed in decreasing a gradient of pH, from 7.0 to 4.0. All A beta peptides were recovered from IDA-Ni(II) columns in a decreasing pH gradient from 7.0 to 4.0, within the pH range from 5.6 to 5.1. A beta(1-42) peptide was strongly retained on IDA-Zn(II) at pH 4.0, but its A beta(1-28) and A beta(1-16) were only transiently retained on IDA-Zn(II) columns when applied at pH 6.1. We submit that histidine clusters, residing both in the Alzheimer's beta-amyloid peptide and in most of the APP/APLP superfamily of proteins, constitute high-affinity binding sites for immobilized metal chelates.
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Parthasarathy R, Parthasarathy L, Vadnal R. Brain inositol monophosphatase identified as a galactose 1-phosphatase. Brain Res 1997; 778:99-106. [PMID: 9462881 DOI: 10.1016/s0006-8993(97)01042-1] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
During the course of our analysis of myo-inositol monophosphatase (IMPase), a key enzyme of brain inositol signaling, we found it also hydrolyzes galactose 1-phosphate (Gal 1-P), an intermediate of galactose metabolism. Electrophoretically homogeneous IMPase was prepared from three different sources: (i) bovine brain, (ii) rat brain, and (iii) human brain (recombinant), which demonstrated similar ability to hydrolyze inositol monophosphates and galactose 1-phosphate. The ability of IMPase to use both inositol 1-phosphates and galactose 1-phosphate equally as substrates is of considerable importance in determining lithium's mechanism of action. Our current results suggest that during lithium therapy, both galactose and inositol metabolic pathways can be simultaneously modulated through lithium inhibition of IMPase. Enzyme studies with Mg2+ ions as activators and with Li+, Ca2+, Mn2+, Ba2+ ions as inhibitors demonstrate that IMPase is a single enzyme possessing the ability to hydrolyze both inositol monophosphates and Gal-1-P with equal efficiency. In addition, gel-filtration chromatographic analysis demonstrated that IMPase and galactose 1-phosphatase activities co-purify in our electrophoretically homogeneous enzyme preparations. Our results indicate that lithium inhibition of IMPases at clinically relevant concentrations, may modulate both inositol and galactose metabolism, and identifies yet another carbohydrate pathway utilizing IMPase.
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Parthasarathy R, Srikrishnan T. Cytldlne Cyclic (3′, 5′) Monophosphate: Cyclic Nucleotide With a Non-Characteristic Ribose Ring Conformation. ACTA ACUST UNITED AC 1997. [DOI: 10.1080/07328319708002548] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Balakrishnan R, Ramasubbu N, Varughese KI, Parthasarathy R. Crystal structures of the copper and nickel complexes of RNase A: metal-induced interprotein interactions and identification of a novel copper binding motif. Proc Natl Acad Sci U S A 1997; 94:9620-5. [PMID: 9275172 PMCID: PMC23236 DOI: 10.1073/pnas.94.18.9620] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/1997] [Accepted: 07/07/1997] [Indexed: 02/05/2023] Open
Abstract
We report the crystal structures of the copper and nickel complexes of RNase A. The overall topology of these two complexes is similar to that of other RNase A structures. However, there are significant differences in the mode of binding of copper and nickel. There are two copper ions per molecule of the protein, but there is only one nickel ion per molecule of the protein. Significant changes occur in the interprotein interactions as a result of differences in the coordinating groups at the common binding site around His-105. Consequently, the copper- and nickel-ion-bound dimers of RNase A act as nucleation sites for generating different crystal lattices for the two complexes. A second copper ion is present at an active site residue His-119 for which all the ligands are from one molecule of the protein. At this second site, His-119 adopts an inactive conformation (B) induced by the copper. We have identified a novel copper binding motif involving the alpha-amino group and the N-terminal residues.
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Finch CD, Parthasarathy R, Akpati HC, Nordlander P, Dunning FB. Low-energy dissociative electron attachment to CFCl3, CF2Br2, and 1,1,1- and 1,1,2-C2Cl3F3: Intermediate lifetimes and decay energetics. J Chem Phys 1997. [DOI: 10.1063/1.473858] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Parthasarathy L, Parthasarathy R, Vadnal R. Molecular characterization of coding and untranslated regions of rat cortex lithium-sensitive myo-inositol monophosphatase cDNA. Gene 1997; 191:81-7. [PMID: 9210592 DOI: 10.1016/s0378-1119(97)00045-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Lithium sensitive myo-inositol monophosphatase (IMPase) is a pivotal enzyme which controls the levels of brain inositol within the inositol-based signaling system. Its capacity to release free myo-inositol from inositol monophosphates generated from receptor-linked and de novo pathways is crucial to the maintenance of appropriate amounts of intracellular myo-inositol, which is essential for both inositol-based cell signaling and cell volume control. We present here the full length cDNA encompassing the coding and untranslated regions (5'- and 3'-UTRs) of rat brain IMPase. This cDNA was derived from rat cortex mRNA by the RT-PCR technique. Analysis of this cDNA revealed several interesting features which include a short 5'-untranslated region (5'-UTR) of 68 nucleotides followed by coding region of approximately 0.8 kb and a long 3'-untranslated region (3'-UTR) of 1.2 kb. Both 5'-rapid amplification of cDNA ends (5'-RACE) and 3'-RACE techniques were carried out to isolate both UTRs and double stranded sequencing was carried out to its entirety (approximately 2.1 kb) by 'gene walking' using several oligonucleotide primers. All nucleotides were sequenced unambiguously using the sense and antisense strands of DNA. PCR analysis for the coding region and the deduced amino acid sequence demonstrated a DNA fragment of 831 bp and 277 amino acids, respectively, which are strikingly similar to human hippocampal IMPase. The 5'-UTR demonstrated distinct CpG doublets, characteristic of 'housekeeping' genes. The sequence around the initiator methionine, AAGATGG, conforms well to the Kozak consensus sequence for mammalian protein biosynthesis and the 3'-UTR demonstrated three canonical (AATAAT, AATTAA, AATACA) and one unusual polyadenylation signals (ATTAAA) followed by a 31 base poly(A) tail. The presence of a CCTGTG in the 3'-UTR (putative carbohydrate response element) links IMPase mRNA to brain carbohydrate metabolic pathways. Computer analyses demonstrated several unique features of this mRNA, including the potential formation of hairpin loops which might be important in its intracellular regulation and turn-over. In summary, this lithium-sensitive brain IMPase mRNA has the following characteristics: a 5'-CpG-rich short untranslated segment, a highly conserved coding region, and a long 3'-untranslated region with several polyadenylation signals.
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Balakrishnan R, Parthasarathy R, Ramasubbu N. Crystal structure of a dipeptide Boc-Aib-Phe-OMe. THE JOURNAL OF PEPTIDE RESEARCH : OFFICIAL JOURNAL OF THE AMERICAN PEPTIDE SOCIETY 1997; 49:371-4. [PMID: 9211217 DOI: 10.1111/j.1399-3011.1997.tb00888.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
In order to understand the effect of the restrictions posed by the Aib residue on peptide conformation we studied the crystal structure of a dipeptide tBoc-Aib-Phe-OMe. Crystals of this compound are triclinic, space group P1 with a = 9.600(1) A, b = 10.262(1) A, c = 10.799(1) A, alpha = 98.43 degrees (1), beta = 99.18 degrees (1), gamma = 98.87 degrees (1), V = 1021.69(18) A3 and Z = 2. The structure was solved by direct methods and refined to an R-factor of 4.98%. The backbone conformational angles for the Aib residue in molecule A are in the left-handed helical region, while in molecule B they are in the right-handed helical region. The Phe residue in molecule A is in the right-handed helical conformation, while in molecule B it is in the beta-region. The peptide units are trans and show significant deviation from planarity [(omega 1 = 166.67(5) degrees and omega 2 = -177.9(5)].
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Balakrishnan R, Ramasubbu N, Varughese KI, Parthasarathy R. Crystal structure of RNase-form I (complexed with nickel). Acta Crystallogr A 1996. [DOI: 10.1107/s0108767396094755] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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119
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Zeng H, Parthasarathy R, Rampal AL, Jung CY. Proposed structure of putative glucose channel in GLUT1 facilitative glucose transporter. Biophys J 1996; 70:14-21. [PMID: 8770183 PMCID: PMC1224905 DOI: 10.1016/s0006-3495(96)79560-7] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
A family of structurally related intrinsic membrane proteins (facilitative glucose transporters) catalyzes the movement of glucose across the plasma membrane of animal cells. Evidence indicates that these proteins show a common structural motif where approximately 50% of the mass is embedded in lipid bilayer (transmembrane domain) in 12 alpha-helices (transmembrane helices; TMHs) and accommodates a water-filled channel for substrate passage (glucose channel) whose tertiary structure is currently unknown. Using recent advances in protein structure prediction algorithms we proposed here two three-dimensional structural models for the transmembrane glucose channel of GLUT1 glucose transporter. Our models emphasize the physical dimension and water accessibility of the channel, loop lengths between TMHs, the macrodipole orientation in four-helix bundle motif, and helix packing energy. Our models predict that five TMHs, either TMHs 3, 4, 7, 8, 11 (Model 1) or TMHs 2, 5, 11, 8, 7 (Model 2), line the channel, and the remaining TMHs surround these channel-lining TMHs. We discuss how our models are compatible with the experimental data obtained with this protein, and how they can be used in designing new biochemical and molecular biological experiments in elucidation of the structural basis of this important protein function.
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Naik AN, Parthasarathy R, Isaac MK. Brief report: families of rural mentally ill and treatment adherence in district mental health programme. Int J Soc Psychiatry 1996; 42:68-72. [PMID: 8730538 DOI: 10.1177/002076409604200108] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
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121
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Bader AL, Parthasarathy R, Harvey WR. A novel proline, glycine: K+ symporter in midgut brush-border membrane vesicles from larval Manduca sexta. J Exp Biol 1995; 198:2599-607. [PMID: 8576686 DOI: 10.1242/jeb.198.12.2599] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Alkali-cation-dependent uptake of proline and glycine into brush-border membrane vesicles from the midgut of the larval tobacco hornworm Manduca sexta was investigated using rapid filtration assays. Uptake of both amino acids was by electrophoretic symport, with K+ being the favored cation at pH 10. Counterflow accumulation of proline was elicited by glycine and vice versa, suggesting that the two amino acids are transported by a common symporter, which we designate the pro, gly: K+ symporter. L-alpha-Aminoisobutyric acid was the only other amino acid that elicited the accumulation of both proline and glycine. D-Proline was not symported; L-proline, glycine and L-alpha-aminoisobutyric acid appear to be the only substrates of the pro, gly: K+ symporter. Neutral amino acids with relatively short sidechains elicit glycine accumulation, suggesting that glycine may also be symported by the well-established neutral amino acid system. Since proline does not utilize the broad-spectrum, neutral system, its symport appears to be exclusively through the pro, gly: K+ symporter. Proline symport was found mainly in posterior midgut vesicles, suggesting that the pro, gly: K+ symporter may be localized in this region of the midgut.
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Go K, Parthasarathy R. Crystal structure and a twisted beta-sheet conformation of the tripeptide L-leucyl-L-leucyl-L-leucine monohydrate trimethanol solvate: conformation analysis of tripeptides. Biopolymers 1995; 36:607-14. [PMID: 7578952 DOI: 10.1002/bip.360360506] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
In order to test the helical preference of short oligo-L-leucines, we crystallized the tripeptide L-leucyl-L-leucyl-L-leucine (LLL) and carried out x-ray diffraction studies of it (L-leucyl-L-leucyl-Lleucine)2. 3CH3OH. H2O, (C39H84N6O12), crystallized in the monoclinic system, space group P2(1), cell parameters: a = 12.031(2), b = 15.578(3), c = 14.087(2) A, alpha = 90 degrees, beta = 97.29(1) degrees, gamma = 90 degrees, V = 2618.6 A3, MW = 829.1, Dc = 1.051 g cm-3, R index of 0.057 for 4213 reflections (lambda CuK alpha = 1.5418 A) > 2 sigma. LLL takes up the beta-sheet rather than a helical conformation in the crystalline state. The three methanol molecules and the water molecule that constitute the solvent of crystallization form a network of hydrogen bonds to the LLL molecules and to one another. It is rather remarkable that though A and L have stronger helical preferences than G, neither AAA nor LLL form the crystalline helix but GAL does, indicating that the helical preferences depend on the sequence context. The residue L2 in molecule A and the residues L1 and L3 of molecule B do not show the preferred conformation for forming helices. Further, very remarkably, LLL exhibits a unique supersecondary feature of the protein folding topology, namely the twisted beta-sheet, whereas most short peptides show only the classical beta-sheet conformation.(ABSTRACT TRUNCATED AT 250 WORDS)
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Rajeswari R, Sivasubramanian S, Balambal R, Parthasarathy R, Ranjani R, Santha T, Somasundaram PR, Ganapathy S, Sudarsana K, Sayeed ZA. A controlled clinical trial of short-course chemotherapy for tuberculoma of the brain. TUBERCLE AND LUNG DISEASE : THE OFFICIAL JOURNAL OF THE INTERNATIONAL UNION AGAINST TUBERCULOSIS AND LUNG DISEASE 1995; 76:311-7. [PMID: 7579312 DOI: 10.1016/s0962-8479(05)80029-2] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
OBJECTIVE The efficacy of a short-course regimen in the treatment of brain tuberculoma and computerised tomography (CT) scan appearance before, during and after antituberculosis treatment was studied in a controlled clinical trial. DESIGN Patients aged over 5 years with tuberculoma of the brain diagnosed by CT scan were randomly allocated to one of the following 2 regimens: Regimen 1: rifampicin, isoniazid and pyrazinamide daily for an initial 3 months followed by rifampicin and isoniazid twice-weekly for 6 months. Regimen 2: rifampicin, isoniazid and pyrazinamide thrice-weekly for an initial 3 months followed by rifampicin and isoniazid twice-weekly for 6 months. The patients were followed intensively for 2 years from the start of treatment. RESULTS Of the 108 patients analysed (regimen 1: 56, regimen 2: 52), at the end of treatment clinical status was normal in 91% in regimen 1 and 88% in regimen 2. Of the 91 patients with scan assessments, CT scan lesions disappeared at 24 months in 77% of 47 patients in regimen 1 and 80% of 44 in regimen 2, and in both groups 88% of the patients were clinically normal. None had relapses requiring treatment. CONCLUSIONS Short-course regimens of 9 months' duration are effective in the treatment of tuberculoma of the brain; clinical recovery was faster than scan clearance.
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Vadnal R, Parthasarathy R. Myo-inositol monophosphatase: diverse effects of lithium, carbamazepine, and valproate. Neuropsychopharmacology 1995; 12:277-85. [PMID: 7576004 DOI: 10.1016/0893-133x(94)00088-h] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The therapeutic molecular sites of action for the mood-stabilizing medications are unknown. Myo-inositol monophosphatase (E.C. 3.1.3.25) is a major enzyme of the inositol signaling system that has previously been shown to be inhibited by clinically relevant concentrations of lithium, implicating this enzyme as a potential therapeutic site of action in manic-depressive disorder. Inhibition of myo-inositol monophosphatase (IMPase), which converts myo-inositol monophosphates to myo-inositol, results in increased levels of myo-inositol monophosphates and decreased myo-inositol available for the resynthesis of inositol phospholipids. In addition to lithium, carbamazepine and valproate are also used medically to treat manic-depressive disorder. It is of considerable interest to determine whether inhibition of IMPase activity is a common unifying mechanism for mood-stabilizing medications. Using a partially purified myo-inositol monophosphatase preparation derived from bovine brain, we examined the effects of lithium, carbamazepine, and valproate on the IMPase reaction. These results demonstrate that (1) lithium inhibited IMPase activity in the low millimolar range, (2) carbamazepine stimulated the IMPase reaction beginning in the low-micromolar range, and (3) valproate did not demonstrate any stimulation or inhibition of IMPase. We conclude that inhibition of IMPase is not a common neurochemical mechanism for mood-stabilizing medications.
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Viswanathan KS, Parthasarathy R. QCD strings as a constrained Grassmannian sigma model. PHYSICAL REVIEW. D, PARTICLES AND FIELDS 1995; 51:5830-5838. [PMID: 10018339 DOI: 10.1103/physrevd.51.5830] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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