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Iqbal MP, Ali AA, Waqar MA, Mehboobali N. Urinary N-acetyl-beta-D-glucosaminidase in rheumatoid arthritis. Exp Mol Med 1998; 30:165-9. [PMID: 9873839 DOI: 10.1038/emm.1998.24] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Excretion of urinary N-acetyl beta-D-glucosaminidase (NAG) and its isoenzyme patterns were studied in two groups of patients with rheumatoid arthritis (RA) and in normal control subjects. Urine samples were collected from 30 seropositive RA patients, 19 seronegative RA patients, and 15 normal healthy subjects. All the patients and normal subjects were assessed to have normal liver and kidney functions. A small portion of the urine sample was dialyzed against 0.01 M phosphate buffer, pH 7.0 and NAG activity was monitored. Mean +/- SD values of urinary NAG in seropositive RA patients, in seronegative RA patients and in normal healthy subjects were found to be 4.20 +/- 3.73 U/g creatinine, 2.96 +/- 2.11 U/gm creatinine, and 1.71 +/- 0.6 U/g creatinine, respectively. The mean urinary, NAG value in RA patients was found to be significantly higher (P < 0.05) in seropositive RA compared to the mean NAG value in normal healthy subjects and patients with seronegative RA when analyzed by one way ANOVA and Tukey-HSD test. The mean proportion of isoenzyme form B to isoenzyme form A in seropositive RA patients was also found to be significantly different (P < 0.05) from the mean proportion of these forms in normal healthy subjects and seronegative RA patients. There also appears to be a correlation between the concentration of urinary NAG and severity of the disease in seropositive RA.
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Iqbal MP, Baig JA, Ali AA, Niazi SK, Mehboobali N, Hussain MA. The effects of non-steroidal anti-inflammatory drugs on the disposition of methotrexate in patients with rheumatoid arthritis. Biopharm Drug Dispos 1998; 19:163-7. [PMID: 9569999 DOI: 10.1002/(sici)1099-081x(199804)19:3<163::aid-bdd82>3.0.co;2-l] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
We have studied the pharmacokinetics of methotrexate in patients with rheumatoid arthritis concurrently taking the most commonly used non-steroidal anti-inflammatory drugs (NSAIDs), aspirin, diclofenac, naproxen, indomethacin, and ibuprofen. The area under the curve, the total systemic clearance, the distribution volume, and the half-life of methotrexate in patients receiving concurrent NSAID therapy did not change significantly (at p < 0.05). Concurrent treatment with NSAIDs resulted in increased inter-patient variability of methotrexate concentration, possibly as a result of biochemical interactions; however, it does not appear clinically relevant. The data suggest that the NSAIDs do not significantly affect the disposition of methotrexate, contrary to some of the earlier reports.
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Ali AA, Iqbal MP, Hussain MA, Mehboobali N, Beg JA, Rahbar MH. Methotrexate in rheumatoid arthritis: a 2 year experience at a university hospital in Pakistan. J PAK MED ASSOC 1998; 48:3-6. [PMID: 9610077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
In this study we report our two years experience of methotrexate (MTX) in the management of rheumatoid arthritis (RA) at the Aga Khan University Hospital, Karachi. We studied the clinical course of 124 RA patients. The mean age was 44 +/- 11 years (range 19-72) and mean duration of RA was 5 +/- 4 years (range 0.3-25). Female to male ratio was 10:2.4 (100F:24M). All of them were diagnosed according to the criteria set by American Rheumatism Association. The mean value of ESR was 60 +/- 30 (Range 3-128). Fifty one percent had severe disease (> 10 joints involved and evidence of erosions and deformities). Twenty-one patients had extra-articular manifestations. None of them had received MTX previously. Their kidney and liver functions were assessed to be normal. Patients were divided into two groups. One group (n = 92) received MTX (7.5-10 mg/week) as initial treatment, while the other group (n = 32) was given other disease modifying anti-rheumatic drugs (penicillamine, salazopyrin, gold, or chloroquine) followed by MTX. Assessment of the treatment outcome and development of any adverse reactions was carried out at 3-month interval over an average period of 1 year. Assessment of the treatment outcome in the group which received MTX as initial drug revealed the response to be excellent in 13%, good in 70%, fair in 11% and variable in 4%. In the group which received MTX as second-line of therapy, 59% of the patients had the response from good to excellent, while 25% of the patients exhibited poor to fair response. Regarding side-effects of MTX treatment, 57% exhibited none, while 35% had nausea and vomiting. Alopecia was the next common toxicity in these patients. Two individuals had abnormal liver function tests (value twice more than normal), while one developed lung fibrosis. MTX despite its adverse effects in some of the patients is still an effective, well tolerated and inexpensive disease modifying drug in RA.
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Malik IA, Mehboobali N, Iqbal MP. Effect of ifosfamide on intracellular glutathione levels in peripheral blood lymphocytes and its correlation with therapeutic response in patients with advanced ovarian cancer. Cancer Chemother Pharmacol 1997; 39:561-5. [PMID: 9118472 DOI: 10.1007/s002800050616] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The successful outcome of ovarian cancer therapy with alkylating agents and cisplatin is seriously hampered by the development of acquired drug resistance. An increase in intracellular glutathione (GSH) levels in cancer cells is one of the major mechanisms involved. Depletion of GSH overcomes drug resistance and restores the chemosensitivity of malignant cells. Ifosfamide (IFEX), an alkylating agent, has been demonstrated to decrease intracellular GSH levels in vitro in malignant cell lines and in vivo in peripheral blood lymphocytes (PBL) obtained from patients with cancer. We studied the effect of IFEX on intracellular GSH levels in PBL isolated from patients with advanced ovarian cancer who were receiving chemotherapy. A total of 14 patients received IFEX plus mesna as a continuous infusion (1 g/m2 per day) for 6 consecutive days and cisplatin (100 mg/m2) as a 24-h continuous infusion on the 6th day. PBL were isolated prior to the initiation of chemotherapy and on the 3rd and 6th days of IFEX infusion. Intracellular GSH levels were determined by a modification of Tietze's method. IFEX caused a 20% or greater suppression of intracellular GSH levels in nine patients, eight of whom achieved complete remission of their disease. Six patients responded poorly to this chemotherapeutic regimen, five of whom showed no significant suppression of GSH levels. These data suggest that IFEX suppresses intracellular GSH levels in PBL from patients with ovarian cancer and that this suppression correlates closely with the subsequent clinical outcome.
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Iqbal MP, Niazi SK, Mehboobali N, Zaidi AA. Disposition kinetics of aditoprim in two monkeys in comparison to other mammalian species. Biopharm Drug Dispos 1995; 16:713-8. [PMID: 8573690 DOI: 10.1002/bdd.2510160810] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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Iqbal MP, Waqar MA. Basic medical research as a means of solving national health problems. J PAK MED ASSOC 1995; 45:250-2. [PMID: 8683836] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
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Iqbal MP, Niazi SK, Ashfaq MK, Mahboobali N. Pharmacokinetics of aditoprim in normal and febrile sheep. Biopharm Drug Dispos 1995; 16:343-9. [PMID: 7548783 DOI: 10.1002/bdd.2510160410] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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Flavell AJ, Jackson V, Iqbal MP, Riach I, Waddell S. Ty1-copia group retrotransposon sequences in amphibia and reptilia. MOLECULAR & GENERAL GENETICS : MGG 1995; 246:65-71. [PMID: 7823913 DOI: 10.1007/bf00290134] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
We have isolated sequences belonging to Ty1-copia group retrotransposons from the genomes of an amphibian (Pyxicephalus adspersa) and three reptiles (Conolophus subscristatus, Amblyrynchus cristatus and Pytas mucosus). Two different sequences were found in the amphibian (Tpa1 and Tpa2). Each is present in several copies per genome and absent from the genomes of two other amphibian species. The C. subcristatus sequence Tcs1 is present in multiple copies in both its host genome (Galapagos land iguana) and the genome of the related Galapagos marine iguana (A. cristatus). There is little or no polymorphism in Tcs1 insertions between different individual animals, suggesting that this sequence is not transposing rapidly in either iguana genome. The P. mucosus sequence Tpm1 shows a discontinuous distribution in snake species, suggesting that it has either been lost from many lineages during vertical germline transmission or has been transferred horizontally in some snake species. Phylogenetic comparisons of all these sequences with each other and with other members of this retrotransposon group from other animals and plants show that sequences within a particular vertebrate species are most closely related to each other, consistent with a vertical transmission model for their evolution.
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Iqbal MP, Ashfaq MK, Niazi SK, Mahboobali M, Khawaja KN. Pharmacokinetics of aditoprim and trimethoprim in buffalo calves. Biopharm Drug Dispos 1994; 15:173-7. [PMID: 8011968 DOI: 10.1002/bdd.2510150209] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Pharmacokinetic parameters of two antifolates, trimethoprim and aditoprim, were studied in buffalo calves. The elimination half-life of aditoprim (6.14 h) was nearly twice as long as that of trimethoprim (3.08 h) and compares well with values observed in heifers. This longer half-life of aditoprim is a result of its much larger distribution volume (four to five times larger) because the clearance of aditoprim was about twice as high as that of trimethoprim. The longer half-life of aditoprim is expected to give a longer duration of in vivo bacteriostatic activity than that of trimethoprim.
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Iqbal MP, Ali AA, Alvi AA. Severe bone marrow suppression in a patient with rheumatoid arthritis on methotrexate. J PAK MED ASSOC 1993; 43:262-3. [PMID: 8133640] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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Iqbal MP, Zuberi H, Waqar MA, Ahmed M. Thymidylate synthase in normal and cancer tissues. Biochem Soc Trans 1993; 21:187S. [PMID: 8359440 DOI: 10.1042/bst021187s] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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Iqbal MP, Mehboobali N, Waqar MA. Effect of folates and folate antagonists on lipid peroxidation. Biochem Soc Trans 1993; 21:91S. [PMID: 8359544 DOI: 10.1042/bst021091s] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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Iqbal MP, Malik I, Mehboobali N. Appearance of a methotrexate binding plasma protein during high dose methotrexate therapy. J PAK MED ASSOC 1992; 42:193-6. [PMID: 1433799] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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Iqbal MP. Methotrexate as an alternative to surgery in ectopic pregnancy: a new role for an old drug. J PAK MED ASSOC 1992; 42:97-100. [PMID: 1597927] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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Iqbal MP, Rothenberg SP, da Costa M. Evidence for kinetic and immunologic heterogeneity of dihydrofolate reductase in L1210 leukemia cells. BIOCHEMICAL MEDICINE AND METABOLIC BIOLOGY 1991; 46:196-207. [PMID: 1782010 DOI: 10.1016/0885-4505(91)90067-u] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Two species of DHFR were identified in wild-type L1210 murine leukemia cells by analysis of the kinetics of the binding of MTX and dissociation of the MTX-enzyme complex at pH 5.0 and pH 7.2. The two forms of DHFR were also distinguished by immunoinhibition of the binding of MTX and the catalytic reduction of FH2 to FH4 using an antiserum raised to the purified high affinity form of DHFR. The Ka for the binding of MTX by the low affinity form of the enzyme is 4.5 x 10(7) M-1, substantially lower than the reported Ka for the binding of this drug by the high affinity enzyme. The low affinity form of the enzyme catalyzed the reduction of FH2 to FH4 at a rate slower than the high affinity form of DHFR.
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Iqbal MP, Mehboobali N, Waqar MA, Ahmed M. Heterogeneity of methotrexate binding in human colon tumor cells. J PAK MED ASSOC 1991; 41:136-9. [PMID: 1895499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
[3H]-methotrexate binding at pH 5.0 and pH 7.2 by the cytosol of tumor tissues and the surrounding normal areas of the gastrointestinal tract of patients suffering from colon or gastric cancer has been used to identify in these cells the presence of a binder of methotrexate having low-affinity for this drug in addition to the enzyme dihydrofolate reductase. Scatchard analysis of the [3H]-methotrexate binding data by a colon tumor sample also reveals that there are two binders of this drug present in the cytosol of these cells. The association constant (Kass) for one binder of methotrexate is = 5.6 x 10(7) M-1 while the Kass for the second binder is = 1.0 x 10(6) M-1. The two binders do not differ very much in their apparent molecular weight. Upon isoelectric focusing, the tumor cell cytosol resolves into 4 major isoproteins each having the ability not only to bind [3H]-methotrexate but also reduce [3H]-pteroylglutamic acid to [3H]-tetrahydropteroylglutamic acid. This suggests that the two binders of methotrexate may be the two forms of dihydrofolate reductase having different affinities for this anticancer drug.
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Iqbal MP, Mehboobali N, Waqar MA. Yeast cells with a low-affinity binder of methotrexate. Biochem Soc Trans 1991; 19:192S. [PMID: 1889572 DOI: 10.1042/bst019192s] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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Iqbal MP, Mehboobali N, Waqar MA, Zuberi HS. Dihydrofolate reductase from a reptile, uromastix. Biochem Soc Trans 1991; 19:193S. [PMID: 1889573 DOI: 10.1042/bst019193s] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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Iqbal MP, Malik IA. Mega doses of methotrexate in the treatment of osteosarcoma. J PAK MED ASSOC 1990; 40:248-51. [PMID: 2123265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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Iqbal MP, Waqar MA, Mehboobali N, Malik I. A low-affinity binder for methotrexate in human leukaemia cells. Biochem Soc Trans 1990; 18:633-4. [PMID: 2276483 DOI: 10.1042/bst0180633] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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Iqbal MP, Mahboobali N, Niazi SK, Mahmood MA. Pharmacokinetics of aditoprim in goats using a radioassay. Biopharm Drug Dispos 1990; 11:533-41. [PMID: 2207303 DOI: 10.1002/bdd.2510110607] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
A simple, highly sensitive radioassay was developed for the activity of a newly discovered inhibitor of dihydrofolate reductase (DHFR), aditoprim. The procedure is based on the inhibition of binding of [3H]-methotrexate ([3H]MTX) with bacterial dihydrofolate reductase by the antifolate, aditoprim. The analytic sensitivity using this binding inhibition method was less than 5 ng in plasma. The procedure developed requires no extraction of the drug from the plasma. The variation of simultaneous duplicate determinations was 6.3 per cent, whereas the variability of plasma samples assayed on different days was less than 11 per cent. The assay developed was applied to study the pharmacokinetics of aditoprim in the goat. In comparison with trimethoprim (TMP), the new inhibitor of DHFR, aditoprim, had a longer half-life and a larger volume of distribution, suggesting enhanced and prolonged antibacterial activity of aditoprim over TMP.
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Iqbal MP, Khursheed M, Mahboobali N. Methotrexate clearance and clinical toxicity in osteosarcoma following high-dose methotrexate therapy. J PAK MED ASSOC 1989; 39:38-42. [PMID: 2499702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Two patients with osteogenic sarcoma were treated with high-dose methotrexate (MTX) followed by leucovorin 'rescue'. Profiles of MTX clearance from plasma and erythrocytes were obtained. Clearance of the drug from plasma during the first 36 hours appears to be biphasic with the first phase of elimination of the drug being appreciably more rapid than the second phase. The drug had also incorporated into the bone marrow precursor cells and reappeared after a few days in the circulating mature erythrocytes which may later serve as a slow-changing compartment for MTX. Nonspecific binding of the drug to plasma proteins may have been one of the causes of delayed clearance of plasma MTX observed in one of the patients. However, delayed clearance does not appear to correlate with the severity of clinical toxicity which was found to be more pronounced in a patient with a better clearance of the drug. Our results support the more recent concept that enhanced clinical toxicity may not be predictable by monitoring plasma MTX alone.
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Iqbal MP, Rothenberg SP, LaRosa C. Mouse brain contains a high molecular weight nonfunctional protein with antigenic homology to dihydrofolate reductase. Biochem Biophys Res Commun 1986; 141:258-62. [PMID: 3800999 DOI: 10.1016/s0006-291x(86)80362-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The cytosol of brain tissue from mature BDF1 mice contains very little dihydrofolate reductase activity but it does contain a high molecular weight nonfunctional protein which cross-reacts in a radioimmunoassay for the active enzyme. Liver cytosol contains less of this high molecular weight cross-reacting protein and more of the functional dihydrofolate reductase. The cytosol from kidney contains very little of the high molecular weight cross-reacting protein, 95% of the immunoreactive proteins being the functional form of dihydrofolate reductase. The modification of dihydrofolate reductase into a nonfunctional form may be an intrinsic property of some cells and this finding could explain the variability in measuring the activity of this enzyme in brain tissue of mature animals.
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Iqbal MP, Rothenberg SP. Radioenzymatic assay for dihydrofolate reductase using [3H]dihydrofolate. Methods Enzymol 1986; 122:346-9. [PMID: 3517566 DOI: 10.1016/0076-6879(86)22192-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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Iqbal MP. Mechanisms of resistance to methotrexate. J PAK MED ASSOC 1985; 35:348-50. [PMID: 3937906] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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