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Huggett DB, Khan IA, Foran CM, Schlenk D. Determination of beta-adrenergic receptor blocking pharmaceuticals in United States wastewater effluent. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2003; 121:199-205. [PMID: 12521108 DOI: 10.1016/s0269-7491(02)00226-9] [Citation(s) in RCA: 128] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Beta adrenergic receptor antagonists (beta-Blockers) are frequently prescribed medications in the United States and have been identified in European municipal wastewater effluent, however no studies to date have investigated these compounds in United States wastewater effluent. Municipal wastewater effluent was collected from treatment facilities in Mississippi, Texas, and New York to investigate the occurrence of metoprolol, nadolol, and propranolol. Propranolol was identified in all wastewater samples analyzed (n = 34) at concentrations < or = 1.9 microg/l. Metoprolol and nadolol were identified in > or = 71% of the samples with concentrations of metoprolol < or = 1.2 microg/l and nadolol < or = 0.36 microg/l. Time course studies at both Mississippi plants and the Texas plant indicate that concentrations of propranolol, metoprolol, and nadolol remain relatively constant at each sampling period. This study indicates that beta-Blockers are present in United States wastewater effluent in the ng/l to microg/l range.
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Ganzera M, Dharmaratne HRW, Nanayakkara NPD, Khan IA. Determination of saponins and alkaloids in Caulophyllum thalictroides (blue cohosh) by high-performance liquid chromatography and evaporative light scattering detection. PHYTOCHEMICAL ANALYSIS : PCA 2003; 14:1-7. [PMID: 12597249 DOI: 10.1002/pca.666] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The roots of Caulophyllum thalictroides, traditionally used for the treatment of menstrual difficulties and as an aid in childbirth, contain saponins, which are considered to be responsible for the uterine stimulant effects, together with teratogenic alkaloids. An HPLC method has been developed which permits the determination of the triterpene saponins in the plant and also the separation of four alkaloids. The best results were obtained with a C-12 stationary phase using ammonium acetate buffer (pH 8.0) and acetonitrile as mobile phase. Owing to their low UV absorbance, the saponins were detected by evaporative light scattering, whereas the alkaloids were monitored by UV at 310 nm. The identities of the compounds were confirmed in an LC-MS experiment. Different plant samples and commercial products have been analysed using the described method, and remarkable qualitative and quantitative variations were revealed. Comparing the daily uptake of total saponins, a difference of greater than 100-fold was observed within the various products; the alkaloid content on the other hand was more uniform.
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Schaneberg BT, Applequist WL, Khan IA. Determination of aristolochic acid I and II in North American species of Asarum and Aristolochia. DIE PHARMAZIE 2002; 57:686-9. [PMID: 12426949] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 02/27/2023]
Abstract
Wild ginger, Asarum canadense, which has folk uses as a medicinal and food plant, has been reported to contain aristolochic acid I. Rhizomes of North American species of Aristolochiaceae were surveyed for the presence of aristolochic acids by HPLC. Aristolochic acid I (1) and aristolochic acid II (2) were present in Aristolochia species and Hexastylis; 1 alone was detected in multiple accessions of A. canadense and Asarum caudatum, though not in Asarum wagneri. Concentrations in A. canadense were highly variable, reaching as much as 0.037 percent of dry weight.
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Haddad M, Khan IA, Lacaille-Dubois MA. Two new prosapogenins from Albizia adianthifolia. DIE PHARMAZIE 2002; 57:705-8. [PMID: 12426954] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/27/2023]
Abstract
Two new triterpenoidal prosapogenins 1 and 2 were obtained from the mild alkaline hydrolysate of the crude saponin fraction of Albizia adianthifolia (Mimosaceae) roots. Their structures were mainly determined by spectral analyses as acacic acid 3-O-beta-D-xylopyranosyl-(1-->2)-beta-D-fucopyranosyl-(1-->6)- 2-acetylamino-2-deoxy-beta-D-glucopyranoside (1) and acacic acid 3-O-(beta-D-xylopyranosyl-(1-->2)-beta-D-fucopyranosyl-(1-->6)- [beta-D-glucopyranosyl-(1-->2)]-beta-D-glucopyranosyl)-21-O-(6(S)-2- hydroxymethyl-6-methyl-6-O-(beta-D-quinovopyranosyl)-2,7-octadienoyl) ester (2). Furthermore, the known julibroside A3 was isolated from the crude saponin mixture. Compounds 1 and 2 did not show any ability to potentiate in vitro cisplatin cytotoxicity in a human colon cancer cell line.
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80
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Shui Z, Khan IA, Tsuga H, Dobrzynski H, Haga T, Henderson Z, Boyett MR. Role of receptor kinase in long-term desensitization of the cardiac muscarinic receptor-K+ channel system. Am J Physiol Heart Circ Physiol 2002; 283:H819-28. [PMID: 12124232 DOI: 10.1152/ajpheart.00515.2001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Desensitization of the cardiac muscarinic K+ channel was studied in cultured neonatal rat atrial cells and in Chinese hamster ovary (CHO) cells transfected with muscarinic receptor (HM(2)), G protein-coupled inward rectifying K+ channels 1 and 4, and G protein-coupled receptor kinase 2. In atrial cells incubated in 10 microM carbachol for 24 h, channel activity in cell-attached patches was substantially reduced as a result of long-term desensitization. The long-term desensitization was also observed in CHO cells transfected with the wild-type receptor and receptor kinase (as well as the channel). However, long-term desensitization was greatly reduced or abolished if the cells were 1) not transfected with the receptor kinase, 2) transfected with a mutant receptor lacking phosphorylation sites (rather than the wild-type receptor), or 3) transfected with a mutant receptor kinase lacking kinase activity (rather than the wild-type receptor kinase). We suggest that long-term desensitization of the cardiac muscarinic receptor-K+ channel system to muscarinic agonist may involve phosphorylation of the receptor by receptor kinase.
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81
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Bedir E, Khan IA, Walker LA. Biologically active steroidal glycosides from Tribulus terrestris. DIE PHARMAZIE 2002; 57:491-3. [PMID: 12168535] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/26/2023]
Abstract
The steroidal saponin constituents obtained from Tribulus terrestris were tested for their antimicrobial and cytotoxic effects. The spirostanol-based steroidal saponins 1-3 exhibited remarkable activity against fungal organisms (Candida albicans and Cryptococcus neoformans) and cancer cell lines [human malignant melanoma (SK-MEL), human oral epidermoid carcinoma (KB), human breast ductal carcinoma (BT-549), and human ovary carcinoma (SK-OV-3)], while none of the compounds possessing the furostanol framework 4-7 showed activity. The most active spirostanol glycoside, compound 3 exhibited a broad range of anticancer activity against cell lines, SK-MEL, KB, BT-549 and SK-OV-3 at IC50s of 6.0, 7.0, 6.0 and 8.2 micrograms/ml, respectively, while compounds 1 and 2 showed selective cytotoxicity against SK-MEL at 6.7 and 9.1 micrograms/ml, respectively. The minimum inhibitory concentrations (MIC) in antifungal bioassay for compounds 1-3 varied from 1.5 to 6.2 micrograms/ml, which prompted to conclude certain structural features are required for these bioactivities.
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Ganzera M, Zhao J, Khan IA. Hypericum perforatum--chemical profiling and quantitative results of St. John's Wort products by an improved high-performance liquid chromatography method. J Pharm Sci 2002; 91:623-30. [PMID: 11920747 DOI: 10.1002/jps.10057] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The analysis of flavonoids, naphthodianthrones, and the phloroglucinol derivative hyperforin in H. perforatum is described in this article. In a 35-min HPLC run nine major compounds could be identified and baseline separated in the methanolic plant extracts. For an optimum separation the mobile phase consisted of 10 mM ammonium acetate buffer (pH 5.0) and an acetonitrile/methanol mixture; a Synergi MAX-RP 80 A column (C-12 material) was used as stationary phase. Detection was performed at 270 nm, and the identity of the compounds was confirmed in an LC-MS experiment. Commercial St. John's Wort products were analyzed and qualitative and quantitative results are discussed.
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Khan IA, Reddy BV, Mahboob M, Rahman MF, Jamil K. Acute and sub-acute effects of 2-butenoic acid-3-(diethoxy phosphinothioyl) methyl ester (RPR-II) on testis of albino rat. INDIAN JOURNAL OF EXPERIMENTAL BIOLOGY 2002; 40:162-8. [PMID: 12622178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 03/01/2023]
Abstract
Acute and sub-acute toxic effects of a novel phosphorothionate coded as RPR-II on testis of albino rats were studied. In acute study rats received a single dose of 12.3 mg/kg of RPR-II and sacrificed after 24 hr. For sub-acute study 0.58 mg/kg/day was administered orally to rats for 10 and 21 days. Acute exposure of rats to RPR-II brought no change either in the gonadosomatic index (GSI) or in the structure of testis or in the serum levels of testosterone. Testis glutathione (GSH) level and glutathione S-transferase (GST) activity was significantly decreased whereas, acid phosphatase (AcP) levels increased significantly at 24 hr post-treatment. On 7th day (withdrawal period) after the cessation of the treatment the GSH, GST, AcP, and AkP levels reached to near control. The sub-acute study revealed a significant decrease in GSI on 10th and 21st day of the treatment. In contrast, a time-dependent and significant increased in GSH level and GST activity was observed on 100th and 21st day of post-treatment, except GSH level on 10th day, which was declined. Due to RPR-II treatment the testis AcP and alkaline phosphatase (AkP) levels were significant at both 10th and 21st day of medication but AcP levels were increased whereas AkP levels decreased. The histopathological studies on day 10th showed considerable loss of spermatozoids in testis and at 21st day complete derangement of cellular organization was observed. Testosterone levels decreased significantly on 10th day and remained significantly low at 21st day. However, withdrawal studies showed a recovery in testis of rat treated with RPR-II. GST, GSH, GSI, AcP and AkP values recovered, testosterone levels were also well recovered but recovery in testis structure remained at a low profile. The present study suggests that RPR-II may cause testicular toxicity in rats affecting the normal functioning of testis and it also gave some new information in withdrawal studies.
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Mehta NJ, Khan IA, Mehta RN, Tejani F, Vasavada BC, Sacchi TJ. End-of-life care-related publications in cardiology journals. Am J Cardiol 2001; 88:1460-3, A9. [PMID: 11741578 DOI: 10.1016/s0002-9149(01)02138-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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85
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Mikell JR, Ganzera M, Khan IA. Analysis of sesquiterpenes in Valeriana officinalis by capillary electrophoresis. DIE PHARMAZIE 2001; 56:946-8. [PMID: 11802657] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
A capillary electrophoresis (CE) method permitting the determination of the main sesquiterpenes in Valeriana officinalis has been developed. A separation of valerenic acid and its hydroxy and acetoxy derivatives, three compounds characteristic for the species, was achieved using a 40 mM phosphate-borate buffer at pH 8.5, which contained 10% isopropanol as organic modifier. Applied temperature and voltage were 35 degrees C and 17.5 kV, respectively. This setup allowed a baseline separation of the three compounds within 8 min, with a detection limit of 5.8 micrograms/ml or less. Out of six market products analyzed, only one contained a detectable amount of the marker compounds, with 0.54% of hydroxyvalerenic acid and 0.13% valerenic acid, respectively. The quantitative results were comparable to those obtained by HPLC.
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86
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Abourashed EA, Khan IA. GC determination of parthenolide in feverfew products. DIE PHARMAZIE 2001; 56:971-2. [PMID: 11802663] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
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87
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Ganzera M, Crockett S, Tellez MR, Khan IA. Determination of nepetalactone in Nepeta cataria by reversed phase high performance liquid chromatography. DIE PHARMAZIE 2001; 56:896-7. [PMID: 11817179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
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88
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Ganzera M, Bedir E, Khan IA. Determination of steroidal saponins in Tribulus terrestris by reversed-phase high-performance liquid chromatography and evaporative light scattering detection. J Pharm Sci 2001; 90:1752-8. [PMID: 11745732 DOI: 10.1002/jps.1124] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
This paper describes the first analytical method suitable for the determination of steroidal saponins in Tribulus terrestris. A separation by high performance liquid chromatography (HPLC) was achieved by using a reversed-phase (RP-18) column, evaporative light scattering (ELS) detection, and a water/acetonitrile gradient as the mobile phase. The marker compound, protodioscin, was detected at a concentration as low as 10.0 microg/mL. Several different samples of plant material were successfully analyzed, and depending on origin and plant part used for extraction, significant differences in the composition of the saponins were observed. The analysis of market products showed considerable variations of 0.17 to 6.49% in the protodioscin content.
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Bedir E, Tatli II, Calis I, Khan IA. Trojanosides I-K: new cycloartane-type glycosides from the aerial parts of Astragalus trojanus. Chem Pharm Bull (Tokyo) 2001; 49:1482-6. [PMID: 11724245 DOI: 10.1248/cpb.49.1482] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Three new cycloartane-type triterpene glycosides have been isolated from the aerial parts of Astragalus trojanus. The structures were established mainly by a combination of one- and two-dimensional NMR techniques [1H-1H-correlation spectroscopy (COSY), 1H-13C-heteronuclear multiple quantum correlation spectroscopy (HMQC), and 1H-13C-heteronuclear multiple-bond correlation spectroscopy (HMBC)] and high resolution electrospray ionization mass spectrometry (HR-ESI-MS) as 3-O-beta-(2',3'-di-O-acetyl)-D-xylopyranosyl-6-O-beta-D-glucopyranosyl-16-O- acetoxy-20(R),24(S)-epoxycycloartane-3beta,6alpha,16beta,25-tetrol, 3-0-[alpha-L-rhamnopyranosyl-(1-->2)-beta-(3',4'-di-O-acetyl)-D-xylopyranosyll-6-O-beta-D-xylopyranosyl-20(R),24(S)-epoxycycloartane-3p,6alpha,16beta,25-tetrol, 3-O-beta-D-xylopyranosyl-6,16-di-O-beta-D-glucopyranosyl-20(R)24(S)-epoxycycloartane-3beta,6alpha,16beta,25-tetrol.
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Abstract
Peripartum cardiomyopathy is an under-recognized form of dilated cardiomyopathy of unknown cause and is associated with excess morbidity and mortality in women of childbearing age. Incidence of peripartum cardiomyopathy ranges from 1 in 1,300 to 1 in 15,000 pregnancies. The diagnostic criteria are onset of heart failure in the last month of pregnancy or in first 5 months postpartum, absence of determinable cause for cardiac failure, and absence of a demonstrable heart disease before the last month of pregnancy. Multiparity, twin births, advanced maternal age, preeclampsia, gestational hypertension, and black race are known risk factors. The exact cause of peripartum cardiomyopathy is unclear. The clinical presentation of patients with peripartum cardiomyopathy is similar to that of patients with systolic congestive heart failure. Little is known about the therapy of this disease, and the medical treatment is limited to the use of drugs for symptomatic control. Prospective, randomized, double-blind studies are needed to define the role of immunosuppressive treatment and to evaluate the role of conventional treatment of dilated cardiomyopathy in reducing the mortality rate of peripartum cardiomyopathy. About half the patients of peripartum cardiomyopathy recover without any complications. The prognosis is poor in patients with persistent cardiomyopathy. Persistence of disease after 6 months indicates irreversible cardiomyopathy and portends worse survival. The risk of developing peripartum cardiomyopathy in subsequent pregnancies remains high. The clinical and therapeutic aspects of the peripartum cardiomyopathy are discussed.
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91
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Ganzera M, Khan IA. A reversed phase high performance liquid chromatography method for the analysis of boswellic acids in Boswellia serrata. PLANTA MEDICA 2001; 67:778-780. [PMID: 11731931 DOI: 10.1055/s-2001-18346] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
An HPLC method for the separation of boswellic acids, the active constituents in Boswellia serrata resin has been developed. The first accurate determination of 6 individual acids was possible in the resin as well as in multi-component preparations. By using an acidic mobile phase, raised temperature and a 4 microm Synergi MAX-RP 80 A column the acids could be detected at levels as low as 0.9 microg/ml. The study of market products revealed significant variations in the content of these pharmacologically active compounds in commercial samples.
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Li XC, Barnes DL, Khan IA. A new lignan glycoside from Eleutherococcus senticosus. PLANTA MEDICA 2001; 67:776-778. [PMID: 11731930 DOI: 10.1055/s-2001-18352] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
A new lignan glycoside, named eleutheroside E(2) (1), has been isolated from the roots of Eleutherococcus senticosus (known as "Siberian ginseng"), along with isomaltol 3-O-alpha-D-glucopyranoside (2), eleutherosides B, E and E(1), and thymidine. The structure of 1 was established by spectral interpretations as episyringaresinol 4"-O-beta-D-glucopyranoside. Compound 2 is described here for the first time as a naturally occurring compound.
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Wattanasuwan N, Khan IA, Gowda RM, Vasavada BC, Sacchi TJ. Effect of acute myocardial infarction on cholesterol ratios. Chest 2001; 120:1196-9. [PMID: 11591560 DOI: 10.1378/chest.120.4.1196] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
OBJECTIVE In patients with acute myocardial infarctions (MIs), cholesterol levels are no longer valid after 24 h from presentation because acute MI causes a rapid decline in serum levels of total cholesterol, low-density lipoprotein (LDL) cholesterol, and high-density lipoprotein (HDL) cholesterol. The objective of this study was to evaluate the effect of acute MI on the total cholesterol/HDL cholesterol ratio and the LDL cholesterol/HDL cholesterol ratio. METHODS The study consisted of 45 patients who were admitted to the hospital with acute MIs. Serum levels of total cholesterol, HDL cholesterol, LDL cholesterol, and triglycerides were determined on day 1 post-MI and day 4 post-MI. The total cholesterol/HDL cholesterol ratio and the LDL cholesterol/HDL cholesterol ratio were calculated. Serum lipid levels and cholesterol ratios were compared between day 1 post-MI and day 4 post-MI. RESULTS From day 1 post-MI to day 4 post-MI, the mean (+/- SD) serum levels of total cholesterol (188.4 +/- 52.5 vs. 170.5 +/- 57.2 mg/dL, respectively; p = 0.01), LDL cholesterol (120.3 +/- 48.9 vs. 105.9 +/- 43.0 mg/dL, respectively; p = 0.009), and HDL cholesterol (45.0 +/- 18.5 vs 39.3 +/- 16.1 mg/dL, respectively; p < 0.001) decreased, but the mean serum level of triglycerides (119.2 +/- 81.2 vs 149.3 +/- 68.3 mg/dL, respectively; p = 0.006) increased. The cholesterol ratios, however, remained unchanged between day 1 post-MI and day 4 post-MI. The total cholesterol/HDL cholesterol ratio was 4.59 +/- 1.84 on day 1 post-MI and 4.67 +/- 1.77 on day 4 post-MI (change not significant). The LDL cholesterol/HDL cholesterol ratio was 2.96 +/- 1.58 on day 1 post-MI and 2.99 +/- 1.44 on day 4 post-MI (change not significant). CONCLUSION Acute MI does not affect the cholesterol ratios. Therefore, when the absolute levels of serum cholesterol are no longer valid (beyond 24 h after an MI), the cholesterol ratios still could be useful for cholesterol risk assessment in patients with acute MIs.
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Abourashed EA, Galal AM, El-Feraly FS, Khan IA. Separation and quantification of the major daucane esters of Ferula hermonis by HPLC. PLANTA MEDICA 2001; 67:681-682. [PMID: 11582552 DOI: 10.1055/s-2001-17354] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
A simple HPLC method was developed to quantify the major daucane sesquiterpene esters present in herb and roots of Ferula hermonis Boiss. The method utilized a C(18) reversed phase analytical column with isocratic elution for 30 minutes and UV detection at 240 nm. Extracts from two crude plant samples and two commercial products were fingerprinted and quantitatively analyzed.
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Khan IA, Wattanasuwan N, Mehta NJ, Tun A, Singh N, Singh HK, Vasavada BC, Sacchi TJ. Prognostic value of serum cardiac troponin I in ambulatory patients with chronic renal failure undergoing long-term hemodialysis: a two-year outcome analysis. J Am Coll Cardiol 2001; 38:991-8. [PMID: 11583870 DOI: 10.1016/s0735-1097(01)01513-3] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
OBJECTIVES We sought to evaluate the prognostic value of cardiac troponin I (cTnI) in asymptomatic, ambulatory patients with chronic renal failure treated with long-term hemodialysis. BACKGROUND Smaller, short-term follow-up studies on this subject have given conflicting results. METHODS A total of 126 ambulatory patients with chronic renal failure treated with long-term hemodialysis were followed for two years for all-cause mortality, cardiac mortality, all-cause hospital admissions and cardiac hospital admissions. Serum cTnI was measured before dialysis at the time of study entry. RESULTS One hundred two patients had normal serum levels of cTnI (< or =0.03 ng/ml) and 24 patients had elevated levels (0.015 +/- 0.007 vs. 0.053 +/- 0.029 ng/ml, p < 0.0001). No significant difference in all-cause mortality (20 vs. 4 deaths), cardiac mortality (4 vs. 1 death), all-cause hospital admissions (1.74 +/- 1.72 vs. 1.25 +/- 1.19 admissions/patient) or cardiac admissions (0.52 +/- 0.89 vs. 0.33 +/- 0.76 admissions/patient) was present between the patients with normal cTnI levels and those with elevated cTnI levels. Serum cTnI was not significantly different between patients who died versus those who survived (0.022 +/- 0.019 vs. 0.022 +/- 0.021 ng/ml). Serum cTnI was not an independent predictor of all-cause mortality, cardiac mortality, all-cause admissions or cardiac admissions. Age (older) and serum albumin (lower) were independent predictors of all-cause mortality, whereas a history of myocardial infarction was an independent predictor of cardiac mortality. Serum sodium (lower) was an independent predictor of all-cause hospital admissions, whereas hypertension and previous myocardial infarction were independent predictors of cardiac admissions. The best predictors of the time to death were age (older) and serum sodium level (lower), irrespective of the serum cTnI levels. CONCLUSIONS Cardiac troponin I has a limited role in predicting mortality and hospital admissions in asymptomatic patients with chronic renal failure treated with long-term hemodialysis.
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Muhammad I, Li XC, Dunbar DC, ElSohly MA, Khan IA. Antimalarial (+)-trans-hexahydrodibenzopyran derivatives from Machaerium multiflorum. JOURNAL OF NATURAL PRODUCTS 2001; 64:1322-1325. [PMID: 11678659 DOI: 10.1021/np0102861] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Bioassay-guided fractionation of Machaerium multiflorum yielded the hitherto unreported (+)-trans-hexahydrodibenzopyrans machaeriol A (1) and machaeriol B (2), as well as the known guaiane sesquiterpene (-)-kessane. Structure elucidation was based on (1)H and (13)C NMR data, mainly 2D NMR (1)H-(1)H COSY, (1)H-(13)C HMQC, (1)H-(13)C HMBC, and (1)H-(1)H NOESY experiments. This is the first report of the hexahydrodibenzopyrans from a higher plant other than the genus Cannabis. The cannabimimetic activity was thus evaluated by radioligand binding assay for cannabinoid receptor CB1, which indicated, notably, that both 1 and 2 were inactive. In addition, the cross reactivity of 1 and 2 toward antibodies designed for urinary metabolites of cannabinoids was evaluated with the EMIT and On Line cannabinoids assays. Both compounds showed no response at 100 000 ng/mL in both assays. Machaeriol B (2) demonstrated in vitro antimalarial activity (IC(50) = 120 ng/mL) against Plasmodium falciparum W-2 clone.
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Ganzera M, Zhao J, Khan IA. Analysis of terpenelactones in Ginkgo biloba by high performance liquid chromatography and evaporative light scattering detection. Chem Pharm Bull (Tokyo) 2001; 49:1170-3. [PMID: 11558605 DOI: 10.1248/cpb.49.1170] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A reversed phase HPLC method permitting the determination of 5 terpenelactones in Ginkgo biloba, without the need of any sample preparation is presented in this paper. The compounds were successfully separated within 25 min by using a C-12 column, an evaporative light scattering (ELS) detector and a mobile phase comprising of ammonium acetate buffer, methanol and isobutanol. All terpenelactones were detectable at concentrations as low as 20.3 microg/ml. The analysis of G. biloba market products showed remarkable variations in the lactone content, and more than 2 fold differences in the suggested daily doses of the total lactones, from 8.84 mg to 18.28 mg, respectively.
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Nair CK, Khan IA, Esterbrooks DJ, Ryschon KL, Hilleman DE. Diagnostic and prognostic value of Holter-detected ST-segment deviation in unselected patients with chest pain referred for coronary angiography: a long-term follow-up analysis. Chest 2001; 120:834-9. [PMID: 11555517 DOI: 10.1378/chest.120.3.834] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
OBJECTIVE To evaluate the diagnostic and prognostic significance of ST-segment deviation detected by ambulatory Holter monitoring in unselected chest pain patients referred for coronary angiography. METHODS Two hundred seventy-seven patients (71% were men) who underwent coronary angiography for evaluation of chest pain were studied with 24-h ambulatory Holter monitoring within 72 h of angiography. A lumen diameter reduction of > or = 50% was considered coronary artery disease. The ST-segment deviation was defined as > or = 1-mm deviation from the baseline lasting > or = 1 min separated by a minimum of 1 min. The patients were followed up for 65 +/- 21 months (mean +/- SD) for occurrences of death, myocardial infarction, hospitalization for unstable angina, and need for revascularization. RESULTS Of the 277 patients, 223 (80%) had coronary artery disease. The prevalence of coronary artery disease was not significantly different in patients with (43 of 48 patients; 90%) and without (180 of 229 patients; 79%) Holter-detected ST-segment deviation. The diagnostic accuracy of Holter-detected ST-segment deviation in predicting the presence of coronary artery disease was poor (33%), with a sensitivity of 19% and a specificity of 91%. The presence of Holter-detected ST-segment deviation was not predictive of future cardiac events or death. CONCLUSION The ST-segment changes detected on ambulatory Holter monitoring are of limited value in identifying coronary artery disease and predicting the future adverse cardiac events or death in unselected patients with chest pain.
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Chaudhuri AR, Khan IA, Ludueña RF. Detection of disulfide bonds in bovine brain tubulin and their role in protein folding and microtubule assembly in vitro: a novel disulfide detection approach. Biochemistry 2001; 40:8834-41. [PMID: 11467944 DOI: 10.1021/bi0101603] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Cysteine residues in tubulin are actively involved in regulating ligand interactions and microtubule formation both in vivo and in vitro. These cysteine residues are sensitive reporters in determining the conformation of tubulin. Although some of the cysteines are critical in modulating drug binding and microtubule assembly, it is not clear how many of these normally exist as disulfides. The controversy regarding the disulfide bonds led us to develop a disulfide detection assay to reexamine the presence of the disulfide linkages in purified alphabeta tubulin and explore their possible biological functions in vitro. The accessible cysteine residues in alphabeta tubulin were alkylated with an excess of iodoacetamide to prevent artifactual generation of disulfide linkages in tubulin. After removal of excess iodoacetamide, tubulin was unfolded in 8 M urea. Half of the unfolded tubulin was treated with dithiothreitol to reduce any disulfide bonds present. The aliquots were then treated with iodo[(14)C]acetamide and the incorporation of radioactivity was measured. We also used the same approach to detect the disulfide linkages in the tubulin in a whole-cell extract. We found in both cases that the samples which were not treated with dithiothreitol had little or no incorporation of iodo[(14)C]acetamide, while the others that were treated with dithiothreitol had significant amounts of (14)C incorporation into tubulin. Moreover, the reduction of the disulfide linkages in tubulin resulted in inhibition of microtubule assembly (29-54%) and markedly affected refolding of the tubulin from both an intermediate and a completely unfolded state. All these data therefore suggest that tubulin has intrachain disulfide bonds in the alpha- and beta-subunits and that these disulfides assist in correct refolding of tubulin from the intermediate unfolded state or help to recover the hydrophobic domains from the completely unfolded state. These disulfides also regulate microtubule assembly and the stability of tubulin in vitro. Our results suggest that tubulin disulfides may play a role in tubulin folding and that thiol-disulfide exchange in tubulin could be a key regulator in microtubule assembly and dynamics of tubulin in vivo.
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Khan IA, Reddy BV, Mahboob M, Rahman MF, Jamil K. Effects of phosphorothionate on the reproductive system of male rats. JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART. B, PESTICIDES, FOOD CONTAMINANTS, AND AGRICULTURAL WASTES 2001; 36:445-456. [PMID: 11495022 DOI: 10.1081/pfc-100104188] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Acute and Sub-acute toxic effects of a new pesticide phosphorothionate coded as RPR-V on testis of albino rat were studied. For the acute study, rats received a single dose of 30 mg/kg of RPR-V and sacrificed after 24 hours. For the Subacute study, 1.42 mg/kg/day was administered orally to rats for 10 days and 21 days. Acute exposure of rats to RPR-V brought no change either in the Gonadosomatic Index (GSI) or in the structure of testis or in the serum levels of Testosterone. Similarly, no significant change was observed in the Glutathione S-transferase (GST) activity. But, in testis there was significant increased in the reduced Glutathione (GSH) and Acid Phosphatase (AcP), whereas Alkaline Phosphatase (AkP) levels decreased significantly at 24hr post treatment. On 7th day (withdrawal period) after the cessation of the treatment the GSH, AcP, and AkP levels reached to near control. The sub-acute study revealed a significant post treatment. Due to RPR-V treatment the testis AcP levels increased significantly at 21st day of medication but AkP levels decreased both at 10th and 21st day of post treatment. Histopathological studies showed that after 10th day testis showed considerable loss of spermatozoids and at 21st day complete derangement of cellular organization was observed. Testosterone levels decreased significantly after 10th day and remained significantly low at 21st day. However, withdrawal studies showed a recovery in testis of rat treated with RPR-V. GST, GSH, GSI, AcP and AkP values were recovered, testosterone levels were also recovered but recovery in testis structure remained at a low profile.
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