1226
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Khan S, Rahman AM, Payne JF, Rahimtula AD. Mechanisms of petroleum hydrocarbon toxicity: studies on the response of rat liver mitochondria to Prudhoe Bay crude oil and its aliphatic, aromatic and heterocyclic fractions. Toxicology 1986; 42:131-42. [PMID: 2948297 DOI: 10.1016/0300-483x(86)90004-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The effect of Prudhoe Bay crude oil (PBCO) and its different fractions [aliphatic, aromatic, heterocyclic (NOS)] on the bioenergetic functions of isolated rat liver mitochondria were studied. A DMSO extract of PBCO inhibited state 3 respiration (in the presence of ADP) with either succinate or beta-hydroxybutyrate as substrate. The ascorbate-TMPD dependent state 3 respiration was not affected. Succinate dehydrogenase and beta-hydroxybutyrate dehydrogenase activities were also lost in the presence of the PBCO extract suggesting that inhibition of state 3 respiration may be due to blockage of the electron transport chain. Stimulation of state 4 respiration (in the absence of ADP) and of the oligomycin sensitive ATPase activity by the PBCO extract was observed. Fractionation of PBCO indicated that the aromatic fraction was mainly responsible for its inhibitory effects. By comparison, the heterocyclic fraction had weak inhibitory properties while the aliphatic fraction was essentially inactive. It is concluded that the aromatic components of PBCO inhibit mitochondrial respiration and oxidative phosphorylation mainly through impairment of the mitochondrial membrane and inhibition of beta-hydroxybutyrate and succinate dehydrogenase supported electron transfer activities of the respiratory chain.
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1227
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Khan S, Payne JF, Rahimtula AD. Mechanisms of petroleum hydrocarbon toxicity: destruction of liver microsomal and mitochondrial calcium pump activities by a Prudhoe Bay crude oil. JOURNAL OF BIOCHEMICAL TOXICOLOGY 1986; 1:31-43. [PMID: 3271883 DOI: 10.1002/jbt.2570010404] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Administration of Prudhoe Bay crude oil (PBCO) to rats resulted in an abrupt drop in liver mitochondrial and microsomal ATP-dependent calcium uptake activity. Also, in vitro incubations of either mitochondria or microsomes in the presence of a dimethyl sulfoxide (DMSO) extract of PBCO resulted in a dose-dependent inhibition of calcium influx. The release of calcium from calcium-loaded mitochondria and microsomes was also observed in the presence of the PBCO extract. At concentrations which effect calcium sequestration, the PBCO extract produced swelling of mitochondria. Microsomal ATPase activity in the presence or absence of calcium was unaffected by PBCO. The results indicate that increased permeability of the membranes to calcium is a contributory factor in the inhibition of calcium uptake by PBCO.
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1228
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Khan S, Mahtab H, Khan AK, Banik NG, Kashem M. The interrelationship between growth hormone, cortisol, and insulin in diabetic patient. BANGLADESH MEDICAL RESEARCH COUNCIL BULLETIN 1986; 12:59-67. [PMID: 3551909] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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1229
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Butler M, Khan S. Immunoreactive calcitonin in amyloid fibrils of medullary carcinoma of the thyroid gland. An immunogold staining technique. Arch Pathol Lab Med 1986; 110:647-9. [PMID: 2424399] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
A lymph node containing metastatic medullary carcinoma of the thyroid gland was examined immunohistochemically for the presence of calcitonin by light and electron microscopy. Electron microscopy showed dense, selective labeling of the tumor-associated amyloid fibrils and labeling of the scanty intracytoplasmic neurosecretory granules. By light microscopy, a few tumor cells showed strong staining, whereas the amyloid fibrils showed equivocal staining.
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1230
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Khan S, Payne JF, Rahimtula AD. Mechanisms of petroleum hydrocarbon toxicity: functional changes in rat liver mitochondria after exposure to a Prudhoe Bay Crude Oil. Toxicol Lett 1986; 32:141-6. [PMID: 3738925 DOI: 10.1016/0378-4274(86)90060-3] [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: 01/07/2023]
Abstract
Administration of a Prudhoe Bay Crude Oil (PBCO) to rats (5 ml/kg/day for 2 days) resulted in a 30-35% inhibition of liver mitochondrial state 3 respiration with beta-hydroxybutyrate or succinate as substrates. beta-Hydroxybutyrate dehydrogenase, succinate dehydrogenase, NADH oxidase and succinate oxidase activities were also decreased in PBCO-treated rats. A significant increase in latent ATPase activity was also observed. Our results suggest that PBCO exerts its effects on liver mitochondria through the inhibition of beta-hydroxybutyrate- and succinate-supported electron transfer activities and by impairment of the mitochondrial membrane.
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1231
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Kohan S, Fröysa B, Cederlund E, Fairwell T, Lerner R, Johansson J, Khan S, Ritzen M, Jörnvall H, Cekan S. Peptides of postulated inhibin activity. Lack of in vitro inhibin activity of a 94-residue peptide isolated from human seminal plasma, and of a synthetic replicate of its C-terminal 28-residue segment. FEBS Lett 1986; 199:242-8. [PMID: 3084296 DOI: 10.1016/0014-5793(86)80488-4] [Citation(s) in RCA: 36] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
A 94-residue polypeptide isolated from human seminal plasma and its chemically synthesized C-terminal 28-residue segment were studied in an in vitro inhibin bioassay utilizing rat pituitary cell cultures. Both peptides have previously been claimed to have inhibin activities, and the effects on the secretion and cellular content of gonadotrophins (FSH and LH) were now assessed in the in vitro assay. No inhibition was found. After 72 h of culture, both the cellular content and the spontaneous as well as the LHRH-stimulated release of bioactive or immunoactive FSH and LH remained unaffected. Similarly, no effects were found on the storage and/or release of prolactin, growth hormone, or thyrotropin. We conclude that both the native 94-residue peptide and the synthetic replicate of its C-terminal 28-residue segment, do not influence the pituitary FSH secretion when assessed in this in vitro system.
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1232
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Sanderson IR, Kingston JE, Khan S, Walker-Smith JA. Hodgkin's disease complicating Crohn's disease in a child. J R Soc Med 1985; 78:860-1. [PMID: 4045889 PMCID: PMC1289954 DOI: 10.1177/014107688507801014] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
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1233
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Abstract
The motion of tethered cells of Streptococcus was analyzed at low values of protonmotive force (delta p). Cells repeatedly energized and de-energized stopped at discrete angular positions, indicating a rotational symmetry of barriers to rotation of order 5 or 6. At values of delta p smaller than -30 mV, constraints imposed by these barriers were evident when cells were starved and gradually energized, but not when they were energized first and then gradually de-energized. At values of delta p larger than about -30 mV, the cells behaved as if there were no barriers. Cells spinning in this regime also executed rotational Brownian movement. At energy levels above threshold, the motor determines torque; it does not fix the position of the rotor relative to the stator.
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1234
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Abstract
Effects of n-octane and n-nonane (1 ml per kg body weight daily) on hepatic and serum enzymes, which reflect abnormal liver function and concentration of lipid and nucleic acid (serum and liver), were studied after 2 and 7 days intraperitoneal administration to albino rats. Decreased activities of serum acetylcholine esterase and carboxyl esterase were observed, together with an increase in FDP aldolase activity. Significant decrease in the concentration of albumin, total protein, and total and esterified cholesterol in serum have been noted after n-octane and n-nonane administration for 7 days. Also, free cholesterol content of liver was elevated significantly after solvents exposure.
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1235
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1236
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Khan S. Assessment of nutritional status of students of Lady Health Visitor class. J PAK MED ASSOC 1984; 34:272-5. [PMID: 6438357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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1237
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Shousha S, Barrison IG, El-Sayeed W, Khan S, Parkins RA. A study of incidence and relationship of intestinal metaplasia of gastric antrum and gastric metaplasia of duodenum in patients with nonulcer dyspepsia. Dig Dis Sci 1984; 29:311-6. [PMID: 6705642 DOI: 10.1007/bf01318515] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The incidence and relationship of intestinal metaplasia of the gastric antrum and gastric metaplasia of the first part of the duodenum were studied in endoscopic biopsies from 120 patients with nonulcer dyspepsia. Intestinal metaplasia was present in 29% of antral biopsies and gastric metaplasia in 39% of duodenal biopsies, with 9% of patients having both. Intestinal metaplasia was not related to alcohol consumption, but was significantly higher in patients who smoked 10 cigarettes or more daily. (P less than 0.002). Gastric metaplasia was associated with duodenitis. Its incidence was significantly higher in males (P less than 0.001) and in patients with a history of high/moderate alcohol intake (P less than 0.02); these findings are reminiscent of the presence of a similar relationship between these factors and duodenal ulcers and support the suggestion that duodenitis and duodenal ulcers probably represent different parts of a single disease spectrum. The presence of both types of metaplasia in 9% of the patients suggest that factors other than gastric acidity may influence the development of metaplasia.
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1238
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Nigam P, Khan S, Singh R, Kapoor KK, Kumar A, Gupta AK. Chemoprophylaxis of arrhythmias with oral disopyramide in acute myocardial infarction. THE JOURNAL OF THE ASSOCIATION OF PHYSICIANS OF INDIA 1983; 31:759-62. [PMID: 6370949] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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1239
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Khan S. Prevalence of obesity amongst female medical students. J PAK MED ASSOC 1983; 33:266-8. [PMID: 6422078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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1240
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Khan S. Importance of nutrition for female population of reproductive age. J PAK MED ASSOC 1983; 33:264-5. [PMID: 6422077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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1241
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Garud MA, Saraiya UB, Lulla M, Khan S, Paraskar M, Daftary D. Cytology screening program in an urban and rural community in India. Review of a ten-year experience. Acta Cytol 1983; 27:429-31. [PMID: 6576543] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
An approach to the detection and management of early cervical cancer and its precursors utilizing basic and inexpensive equipment and a team of workers comprising physicians, cytotechnicians and social workers in an urban and rural community in India is described. In the ten-year period from 1970 to 1979, a total of 26,217 patients had Papanicolaou smears taken; 104 patients had histologically proven carcinoma in situ or microinvasive cancer of the cervix in which the clinical findings at the time of cell study did not indicate malignancy. The policy of management based on judicial conservatism and essential radicalism gave good survival rates and minimum morbidity.
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1242
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Khan S, Berg HC. Isotope and thermal effects in chemiosmotic coupling to the membrane ATPase of Streptococcus. J Biol Chem 1983; 258:6709-12. [PMID: 6222047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
We measured rates of ATP synthesis by the proton-translocating ATPase of the motile Streptococcus strain V4051. Starved cells were energized artificially by exposing their membranes to a variable electrical potential difference (internal medium negative) and a fixed pH difference (internal medium alkaline). The initial rates of ATP synthesis increased exponentially with protonmotive force. The results were the same in D2O and H2O; there was no solvent isotope effect. At a fixed protonmotive force, the rates were strongly dependent on temperature, as expected for a reaction with a large enthalpy of activation. At a different protonmotive force, the rates varied with temperature in an identical fashion; there was no change in the enthalpy of activation. We conclude that protonation-deprotonation steps are not rate limiting and that the protons that cross the membrane drive ATP synthesis by mass action. The transmembrane electric field acts by changing the concentrations of the reactants, not by changing the configuration of the enzyme-substrate complex.
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1243
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Khan S, Berg HC. Isotope and thermal effects in chemiosmotic coupling to the membrane ATPase of Streptococcus. J Biol Chem 1983. [DOI: 10.1016/s0021-9258(18)32275-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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1244
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Trewhella J, Anderson S, Fox R, Gogol E, Khan S, Engelman D, Zaccai G. Assignment of segments of the bacteriorhodopsin sequence to positions in the structural map. Biophys J 1983; 42:233-41. [PMID: 6871370 PMCID: PMC1329232 DOI: 10.1016/s0006-3495(83)84391-4] [Citation(s) in RCA: 60] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Specific amino acid sequence segments have been assigned to locations in the structural map of bacteriorhodopsin using two-dimensional neutron diffraction data and a model building analysis. Models are constructed computationally by building specific regions of the amino acid sequence as alpha helices and then positioning the helices on axes indicated by the density map of Henderson and Unwin (Nature [Lond.]. 1975, 257:28-32). Neutron diffraction data were collected from samples of stacked, oriented "native" purple membranes as well as purple membranes containing different kinds of deuterated amino acids. Models differing in the assignments of helices to specific axes and in rotations of the helices about those axes were tested against the neutron data using a weighted residual factor to rank the models. This residual factor was calculated between observed and predicted intensity differences for pairs of data sets. Using this approach, a small set of related models has been found that predicts the observed intensity changes between five independent data sets. These models are inconsistent with the proposed locations of the retinal chromophore and the carboxyl terminus and with any of the previously proposed models for bacteriorhodopsin.
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1245
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Khan S, Berg HC. Isotope and thermal effects in chemiosmotic coupling to the flagellar motor of Streptococcus. Cell 1983; 32:913-9. [PMID: 6831561 DOI: 10.1016/0092-8674(83)90076-4] [Citation(s) in RCA: 103] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The torque generated by the flagellar motor of Streptococcus strain V4051 has been determined from rates of rotation of cells tethered by a single flagellum in media of different isotopic composition and temperature. Starved cells were energized artificially with either a potassium diffusion potential or a pH gradient. The torque increased linearly with protonmotive force. Identical results were obtained in media made with D2O or H2O; there was no solvent isotope effect. At a fixed protonmotive force, the torque was approximately constant over a temperature range of 4 degrees -38 degrees C. In cells chemotactically inert to changes in cytoplasmic pH, the motor turned counterclockwise when protons moved inward and clockwise when they moved outward. We conclude that the motor is a reversible engine driven by simple acid-base dissociation. A detailed model is discussed.
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1246
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1247
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Pandya KP, Khan S. Effect of n-octane and n-nonane administration on alkaline phosphatase activity in tissues of female rats. Biochem Pharmacol 1982; 31:201-3. [PMID: 7059361 DOI: 10.1016/0006-2952(82)90211-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Studies on alkaline phosphatase were conducted in albino rats exposed to n-octane or n-nonane for 2 and 7 days; there was an increase in alkaline phosphatase activity of liver, spleen and bone marrow. Increase in spleen alkaline phosphatase activity persisted up to 42 days after single dose of n-octane or n-nonane. Pretreatment with protein synthesis inhibitors, cycloheximide or ethionine removed this observed increase of alkaline phosphatase activity in liver and spleen.
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1248
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DiMauro S, Miranda AF, Khan S, Gitlin K, Friedman R. Human muscle phosphoglycerate mutase deficiency: newly discovered metabolic myopathy. Science 1981; 212:1277-9. [PMID: 6262916 DOI: 10.1126/science.6262916] [Citation(s) in RCA: 92] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Muscle phosphoglycerate mutase activity was decreased (5.7 percent of the lowest control value) in a 52-year-old man with intolerance for strenuous exercise and recurrent pigmenturia since adolescence. All of the other enzymes of glycolysis had normal activities, and glycogen concentration was normal. Electrophoretic, heat lability, and mercury inhibition studies showed that the small residual activity in the patient's muscle was represented by the brain (BB) isoenzyme of phosphoglycerate mutase, suggesting a genetic defect of the M subunit which predominates in normal muscle. The prevalence of the BB isoenzyme in other tissues, including muscle culture, may explain why symptoms were confined to muscle.
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1249
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Ghose JC, Chaudhury A, Khan S, Kumar P. Risk of advanced heart block during surgery in patients with bifascicular block. THE JOURNAL OF THE ASSOCIATION OF PHYSICIANS OF INDIA 1981; 29:435-8. [PMID: 7319997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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1250
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Khan S, Pandya KP. Biochemical studies on the toxicity of n-octane and n-nonane. ENVIRONMENTAL RESEARCH 1980; 22:271-276. [PMID: 6250816 DOI: 10.1016/0013-9351(80)90139-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
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