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Morris HR, Khan MN, Janssen JC, Brown JM, Perez-Tur J, Baker M, Ozansoy M, Hardy J, Hutton M, Wood NW, Lees AJ, Revesz T, Lantos P, Rossor MN. The genetic and pathological classification of familial frontotemporal dementia. ARCHIVES OF NEUROLOGY 2001; 58:1813-6. [PMID: 11708988 DOI: 10.1001/archneur.58.11.1813] [Citation(s) in RCA: 85] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
BACKGROUND Frontotemporal dementia (FTD) is an important cause of neurodegenerative dementia, particularly in younger patients. TAU has been identified as the gene responsible for FTD linked to chromosome 17, but it is likely that there is pathological and genetic heterogeneity among families with FTD. OBJECTIVE To explore the genetic and pathological basis of familial FTD. DESIGN Clinical case series with genetic analysis of each family, and pathological confirmation of diagnosis where possible. SETTING Specialist dementia research group, particularly recruiting patients with young-onset dementia. PATIENTS Twenty-two families with an index member with FTD, meeting Lund-Manchester criteria, and a family history of other affected members with dementia were ascertained. RESULTS Half of the families had mutations in the TAU gene (TAU exon 10 +14, +16, and P301S), and pathological diagnoses were available in 17 of 22 families. Three main pathological diagnoses were made: FTD with neuronal and glial tau deposition, FTD with ubiquitin inclusions, and FTD with neuronal loss and spongiosis but without intracellular inclusions. No cases of familial Pick disease were identified. With the use of the pathological diagnoses, each family with FTD with neuronal and glial tau deposition had a TAU mutation, whereas TAU mutations were not identified in families in the other 2 diagnostic groups. CONCLUSIONS This study illustrates the value of TAU sequencing in FTD and suggests that around one half of individuals with familial FTD have TAU mutations and dementia with tau pathological findings. Furthermore, these data suggest that there are at least 2 additional genes to be identified among families with autosomal dominant FTD.
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Khan MN, Sarwar A. Determination of trace amounts of copper(II) by using catalytic redox reaction between methylene blue and ascorbic acid. ANAL SCI 2001; 17:1195-7. [PMID: 11990595 DOI: 10.2116/analsci.17.1195] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
A sensitive and selective kinetic-spectrophotometric method is proposed for the determination of microg mL(-1) amounts of Cu2+ based on its catalytic effect on the oxidation of L-ascorbic acid by Methylene Blue in a strongly acidic medium. The reaction is monitored spectrophotometrically by measuring the decrease in color intensity of Methylene Blue at 665 nm. The analysis of Cu2+ ion is performed by a fixed-time method. At a given time of 2 min at pH 2.20 and 32 degrees C, the detection limit is 10 ng mL(-1) and the relative standard deviation for 0.4 microg mL(-1) Cu2+ is 3.60% (n = 6). The method is free from most of the interferences and the effect of diverse ions on the determination of Cu2+ is also reported. The proposed method is virtually specific to copper and has been satisfactorily applied to its determination in electric copper wire samples and pharmaceutical products. Results were also verified by the atomic absorption spectrometry technique (AAS).
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Islam MS, Hossain MA, Khan SI, Khan MN, Sack RB, Albert MJ, Huq A, Colwell RR. Survival of Shigella dysenteriae type 1 on fomites. JOURNAL OF HEALTH, POPULATION, AND NUTRITION 2001; 19:177-182. [PMID: 11761771] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Studies have shown that various objects, such as utensils, toys, and clothes, can serve as vehicles for transmission of Shigella spp. Shigellae can become viable but non-culturable (VBNC) when exposed to various environmental conditions as shown in earlier studies. The present study was carried out to detect VBNC Shigella dysenteriae type 1 on various fomites by direct viable counting, polymerase chain reaction (PCR), and fluorescent antibody methods. S. dysenteriae type 1 was inoculated onto cloth, wood, plastic, aluminum, and glass objects. Results showed that 1.5-4.0 hours after inoculation, S. dysenteriae type 1 became non-culturable, and after five days, non-culturable but viable S. dysenteriae type 1 could be detected by both PCR and fluorescent antibody techniques. Fomites can be considered an important potential route of transmission of VBNC S. dysenteriae type 1 and a significant factor in the epidemiology of shigellosis.
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Lone FW, Aziz AB, Khan MN, Pervez S. A case of intramural pregnancy: the importance of differentiation from fibroid uterus. Aust N Z J Obstet Gynaecol 2001; 41:337-8. [PMID: 11592555 DOI: 10.1111/j.1479-828x.2001.tb01242.x] [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: 11/27/2022]
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Islam MS, Siddika A, Khan MN, Goldar MM, Sadique MA, Kabir AN, Huq A, Colwell RR. Microbiological analysis of tube-well water in a rural area of Bangladesh. Appl Environ Microbiol 2001; 67:3328-30. [PMID: 11425764 PMCID: PMC93023 DOI: 10.1128/aem.67.7.3328-3330.2001] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Five tube-wells in Matlab, Bangladesh, were selected for analysis of selected biophysicochemical parameters. The results showed that all tube-well water samples contained zooplankton and bacteria. Results for some of the parameters were outside the accepted limits recommended by the World Health Organization for drinking water. It is concluded that water from tube-wells should be treated if used as drinking water.
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Houlden H, Baker M, Morris HR, MacDonald N, Pickering-Brown S, Adamson J, Lees AJ, Rossor MN, Quinn NP, Kertesz A, Khan MN, Hardy J, Lantos PL, St George-Hyslop P, Munoz DG, Mann D, Lang AE, Bergeron C, Bigio EH, Litvan I, Bhatia KP, Dickson D, Wood NW, Hutton M. Corticobasal degeneration and progressive supranuclear palsy share a common tau haplotype. Neurology 2001; 56:1702-6. [PMID: 11425937 DOI: 10.1212/wnl.56.12.1702] [Citation(s) in RCA: 267] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE To analyze the association of polymorphisms in the tau gene with pathologically confirmed corticobasal degeneration (CBD). BACKGROUND The authors previously described an extended tau haplotype (H1) that covers the human tau gene and is associated with the development of progressive supranuclear palsy (PSP). The authors now extend this analysis to CBD, a neurodegenerative condition with clinical and neuropathologic similarities to PSP. Like PSP, CBD is associated with accumulation of aggregates containing the 4-repeat isoforms of tau. Because of difficulty in diagnosis of CBD, the authors only analyzed cases with pathologically confirmed CBD. METHODS The authors collected 57 unrelated, neuropathologically confirmed cases of CBD. Tau sequencing in these cases failed to show the presence of pathogenic mutations. Polymorphisms that spanned the tau gene were analyzed in all CBD cases and controls. RESULTS Analyzing tau polymorphisms in CBD cases showed that the frequency of H1 and H1/H1 was significantly increased when analyzing all cases and when separating by country of origin. H1 frequency in all CBD cases was 0.921, compared with a control frequency of 0.766 (X(2) = 9.1, p = 0.00255 [1df], OR 3.56 [8.43 > CI 95% > 1.53]). The H1/H1 frequency was also significantly higher at 0.842 compared with 0.596 in age-matched controls (X(2) = 17.42, p = 0.00016, 2df), OR 3.61 [7.05 > CI 95% > 1.85]). CONCLUSIONS The CBD tau association described here suggests that PSP and CBD share a similar cause, although the pathogenic mechanism behind the two diseases leads to a different clinical and pathologic phenotype.
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Gustafsson SE, Khan MN, Eijk JV. Wavelength scanning and mirror alignment of a new multipass Fabry-Perot interferometer. ACTA ACUST UNITED AC 2001. [DOI: 10.1088/0022-3735/12/11/020] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Steckelmacher W, Strong R, Khan MN, Lucas MW. On the validity of beam-foil experiment designed to test theories of 'charge exchange to continuum states' of energetic ions. ACTA ACUST UNITED AC 2001. [DOI: 10.1088/0022-3700/11/15/018] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Soomro I, Khan MN, Muzaffar S, Kayani N, Pervez S, Hussainy AS, Ahmed R, Hasan SH. Retinoblastoma tells the story of our health care system. J PAK MED ASSOC 2000; 50:410-1. [PMID: 11191440] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Abstract
OBJECTIVE To review cases of retinoblastoma. SETTING Department of Pathology Aga Khan University Hospital Karachi. METHOD Twenty-three specimens from cases of retinoblastoma received over a period of eight years were routinely processes and stained with haematoxylin and Eosin stain. Other stains were used for tuberculoses and melanin. Immunochemistry was resorted to in undifferentiated tumors. RESULTS Over 60% cases of retinoblastoma were diagnosed after 5 years and nine cases showed involvement of optinerve. CONCLUSION Late diagnosis of retinoblastoma effects the stage of the tumors and the prognosis.
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Gill MS, Kayani N, Khan MN, Hasan SH. Breast diseases in males--a morphological review of 150 cases. J PAK MED ASSOC 2000; 50:177-9. [PMID: 10979622] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
OBJECTIVE This study was carried out to observe the prevalence breast diseases of males in our setup. METHOD All cases of male breast disease diagnosed from 1991-97. RESULTS One hundred and fifty (150) cases of male breast diseases were diagnosed. Age of the patients ranged from 4 to 90 years, with mean age 38.75 years (median = 33 years). Gynecomastia was the most common pathological abnormality of the male breast (58.66%). Most of the patients presented in the 3rd decade of life. Amongst the malignant conditions, infiltrating ductal carcinoma was most prevalent (82%). Most of the patients with malignancy presented in the 5th and 6th decades of life. CONCLUSION Gynecomastia was the most prevalent male breast disorder, followed by infiltrating ductal carcinoma. Our findings correspond with that of world literature.
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Badgett DK, Comerota MC, Khan MN, Eid IG, Kerr RP, Comerota AJ. Duplex venous imaging: role for a comprehensive lower extremity examination. Ann Vasc Surg 2000; 14:73-6. [PMID: 10629268 DOI: 10.1007/s100169910013] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Real-time compression ultrasound (CU) along with venous duplex imaging is the most commonly performed noninvasive vascular examination. It has become the definitive diagnostic test for most patients with deep venous thrombosis (DVT). Some practioners have recommended that CU alone of the common femoral vein (CFV) and of the popliteal vein (PV) are all that is required since a complete examination is time consuming and calf veins are difficult to visualize. However, if only the CFV and PV are examined, all patients with isolated superficial femoral vein (SFV) and calf DVT remain undiagnosed. The purpose of this study is to establish the value of a comprehensive venous duplex examination compared to CFV and PV compression alone for detecting both proximal and infrapopliteal DVT. From January 1996 through December 1997, the initial venous duplex examinations of 5767 extremities in 3067 patients were reviewed and results tabulated according to presence and location of clot. The ATL 3000 with a 7-14 mHz probe was utilized. Studies were interpreted as normal, proximal DVT (popliteal and above, with or without calf DVT), isolated calf, or isolated SFV deep venous thrombosis. If only the CFV and PV had been examined, 30.3% (isolated SFV + isolated calf vein DVT) of all DVT and 4.5% of proximal DVT would have been missed. A complete venous duplex examination altered the care in 288 (30.3%) of all patients examined who had DVT, and is therefore recommended as the standard noninvasive examination when evaluating patients for acute DVT.
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Khan MN, Ngassapa O, Matee MI. Antimicrobial activity of tanzanian chewing sticks against oral pathogenic microbes. PHARMACEUTICAL BIOLOGY 2000; 38:235-240. [PMID: 21214468 DOI: 10.1076/1388-0209(200007)3831-sft235] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Methanol extracts from the bark and wood of ten plants used as chewing sticks in Morogoro region, in Tanzania, were tested for their ability to inhibit the growth of cariogenic bacteria, Streptococcus mutans , Actinomyces viscosus and a yeast Candida albicans . Screening for antimicrobial activity was done by the agar-hole diffusion method, and minimum inhibitory concentrations (MICs) were determined by the agar dilution method. Extracts from seven out of the ten plants showed varying degrees of growth inhibitory effect on the microorganisms, with Acacia senegal var. senegal stem bark being the most active, followed by the stem bark of Eriosema psoraleoides . Their MICs ranged from 0.63 mg/ml to 5 mg/ml. Three plants Ocimum suave , Opilia celtidifolia and Xerophyta suaveolens did not exhibit any antimicrobial effect. Actinomyces viscosus was relatively more sensitive to the extracts than S. mutans and C. albicans . This study has also demonstrated that most bark extracts possessed antimicrobial activity, while many wood extracts were inactive. It is, therefore, advisable to use, for toothbrushing, unpeeled, rather than peeled chewing sticks, in order to exploit fully their antimicrobial effect. However, additional studies are needed to determine their antiplaque, anticaries and antimycotic effects.
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Findlay JW, Smith WC, Lee JW, Nordblom GD, Das I, DeSilva BS, Khan MN, Bowsher RR. Validation of immunoassays for bioanalysis: a pharmaceutical industry perspective. J Pharm Biomed Anal 2000; 21:1249-73. [PMID: 10708409 DOI: 10.1016/s0731-7085(99)00244-7] [Citation(s) in RCA: 376] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Immunoassays are bioanalytical methods in which quantitation of the analyte depends on the reaction of an antigen (analyte) and an antibody. Although applicable to the analysis of both low molecular weight xenobiotic and macromolecular drugs, these procedures currently find most consistent application in the pharmaceutical industry to the quantitation of protein molecules. Immunoassays are also frequently applied in such important areas as the quantitation of biomarker molecules which indicate disease progression or regression, and antibodies elicited in response to treatment with macromolecular therapeutic drug candidates. Currently available guidance documents dealing with the validation of bioanalytical methods address immunoassays in only a limited way. This review highlights some of the differences between immunoassays and chromatographic assays, and presents some recommendations for specific aspects of immunoassay validation. Immunoassay calibration curves are inherently nonlinear, and require nonlinear curve fitting algorithms for best description of experimental data. Demonstration of specificity of the immunoassay for the analyte of interest is critical because most immunoassays are not preceded by extraction of the analyte from the matrix of interest. Since the core of the assay is an antigen-antibody reaction, immunoassays may be less precise than chromatographic assays; thus, criteria for accuracy (mean bias) and precision, both in pre-study validation experiments and in the analysis of in-study quality control samples, should be more lenient than for chromatographic assays. Application of the SFSTP (Societe Francaise Sciences et Techniques Pharmaceutiques) confidence interval approach for evaluating the total error (including both accuracy and precision) of results from validation samples is recommended in considering the acceptance/rejection of an immunoassay procedure resulting from validation experiments. These recommendations for immunoassay validation are presented in the hope that their consideration may result in the production of consistently higher quality data from the application of these methods.
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Khan MN, Arifin Z, Yusoff MR, Ismail E. Effects of Nonionic, Cationic, and Mixed Nonionic-Cationic Surfactants on the Acid-Base Behavior of Phenyl Salicylate. J Colloid Interface Sci 1999; 220:474-476. [PMID: 10607470 DOI: 10.1006/jcis.1999.6509] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The effects of Brij 35 micelles, CTABr micelles, and mixed Brij 35-CTABr micelles on the acid-base behavior of phenyl salicylate (PST) have been studied in aqueous solution containing 2% v/v acetonitrile. The apparent pK(b) (pK(app)(b)) of PST is decreased by 1.5 pK units with the increase in [Brij 35] from 0 to 0.02 M which is attributed to micellar medium effect. The values of pK(app)(b) remain almost independent of [CTABr] within its range 0.01-0.03 M. The increase in [CTABr] from 0 to 0.03 M in aqueous solution containing 0.02 M Brij 35 has not resulted in a change in pK(app)(b). This shows that the characeristic structural features of nonionic Brij 35 micelles remain essentially unchanged on addition of CTABr under the present experimental conditions. Copyright 1999 Academic Press.
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Khan MN, Cleaton-Jones PE. Dental caries in African preschool children: social factors as disease markers. J Public Health Dent 1998; 58:7-11. [PMID: 9608440 DOI: 10.1111/j.1752-7325.1998.tb02984.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
OBJECTIVE This study investigated the associations between dental caries prevalence and severity and social factors in 3- to 5-year-old African children. METHODS Dental caries was diagnosed in natural light using WHO criteria, minors, and explorers. Socioeconomic information was obtained by questionnaire. RESULTS The percentages of 3-, 4-, and 5-year-olds with any caries experience were 47 percent, 58 percent, and 63 percent, respectively. Mean dmfs scores (SD) were 2.2(3.6), 3.0(3.8), and 3.7(4.1), respectively. Family education was associated with caries prevalence (P = .03) and severity (P = .008) in a multivariable regression model. CONCLUSION In the indigenous African group studied, family education is a disease marker to target in future caries risk evaluations.
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Yee RW, Sullivan LS, Lai HT, Stock EL, Lu Y, Khan MN, Blanton SH, Daiger SP. Linkage mapping of Thiel-Behnke corneal dystrophy (CDB2) to chromosome 10q23-q24. Genomics 1997; 46:152-4. [PMID: 9403072 DOI: 10.1006/geno.1997.5028] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Corneal dystrophy of the anterior basement membrane is a heterogeneous set of diseases characterized by painful, recurrent, bilateral erosions of the cornea, which often result in significant visual impairment. There are several similar but clinically distinct forms of anterior basement membrane/Bowman's membrane disease, including two autosomal dominant forms, Reis-Bücklers and Thiel-Behnke corneal dystrophy. Genes causing autosomal, nonsyndromic corneal dystrophy have been mapped to human chromosomes 1p, 5q, 12q, 16q, 17p, and 20p. Using microsatellite markers closely linked to the known corneal dystrophy loci, we excluded linkage between the known sites and the disease locus in a large, four-generation family with Thiel-Behnke corneal dystrophy. A genome-wide search using a panel of microsatellite markers demonstrated a maximum two-point lod score of 4.0 at 0% recombination between the disease locus in this family and the marker D10S1239, which maps to 10q23-q24. Testing with additional microsatellite markers from 10q places the disease locus between D10S677 and D10S1671, a distance of approximately 12.0 cM, with a maximum multipoint lod score of 5.5. Based on this evidence, we have identified another locus (CDB2) for corneal dystrophy of the anterior basement membrane/Bowman's membrane, Thiel-Behnke type, further demonstrating the exceptional genetic and phenotypic heterogeneity of these diseases.
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Khan MN, Renaud RL, Leatherland JF. Metabolism of estrogens and androgens by embryonic tissues of Arctic charr, Salvelinus alpinus. Gen Comp Endocrinol 1997; 107:118-27. [PMID: 9208311 DOI: 10.1006/gcen.1997.6908] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
This study examines the ability of Arctic charr (Salvelinus alpinus) embryos to metabolize tritiated androstenedione (A4), testosterone (T), 17 beta-estradiol (E2), and estrone (E1) in vitro; the metabolic products were separated by HPLC. A4 was poorly metabolized, with 48 to 64% of the substrate remaining even after 24 hr of incubation. The major metabolites of A4 metabolism are E1 and some other unidentified metabolites. T was mostly converted to A4, along with some reduced steroids, but E2 was a minor metabolite. Further, while E2 was almost exclusively transformed into E1, when E1 was used as the precursor, there was little metabolism; the products of E1 metabolism were small amounts of E1 sulfate, glucuronide, E2, and an unknown metabolite which cochromatographed with reference steroid androstenetrione (also called 11-ketoandrostenedione). It is concluded that in Arctic charr embryos there is preferential expression of a form of 17 beta-hydroxysteroid dehydrogenase resembling the type 2 isozyme of mammals that converts T and E2 to A4 and E1, respectively.
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Khan MN, Renaud RL, Leatherland JF. Steroid metabolism by embryonic tissues of Arctic charr, Salvelinus alpinus. Gen Comp Endocrinol 1997; 105:344-57. [PMID: 9073496 DOI: 10.1006/gcen.1996.6835] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
High-performance liquid chromatography analysis of extracts of Arctic charr (salvelinus alpinus) eggs revealed the presence of several steroids, predominantly progestogens together with testosterone. Yolk sac embryos were incubated with tritiated progesterone ([3H]P4) or 17-hydroxyprogesterone ([3H]17OHP) to examine the ability of the embryos to metabolize progestogens in vitro; both progestogen precursors were converted to various free and conjugated steroids metabolites (sulfates and glucuronides). [3H]P4 was completely metabolized to form steroids that coeluted with standard 11-oxygenated androgens, corticosteroids, progestogens, and some other unidentified metabolites. This report also describes the biosynthesis of 17,20 beta-dihydroxy-4-pregnen-3-one and 17,20 beta-dihydroxy-4-pregnen-3-one 20-sulfate by embryos of Arctic charr that were incubated with 17OHP.
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Islam MN, Alimuzzaman M, Khan MN, Bashar MA, Zafar A. Ruptured aneurysm of the sinus of Valsalva. BANGLADESH MEDICAL RESEARCH COUNCIL BULLETIN 1996; 22:19-26. [PMID: 9037841] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The objective of the present study was to assess the value of imaging techniques in the diagnosis of ruptured aneurysm of sinus of Valsalva (RASV). 38 patients were included in the study. 30 were male and 8 female. Their age ranged from 7 to 55 years (mean 25.8 years). Echocardiographic and doppler studies were done in all cases and 20 patients underwent catheterization and angiography. Two patients were asymptomatic, 20 (53%) had acute onset of symptoms and in the remaining 16 (42%) patients symptoms developed gradually. Twenty two (58%) patients were in NYHA functional class III or IV when first seen. Predominant symptoms were dyspnea (79%), palpitation (55%) and chest pain (52%). A continuous machinery murmur was detected in all the patients with associated thrill in 34 patients. Right coronary sinus (RCS) was the most common sinus involved (89%) followed by the noncoronary sinus (NCS) which was involved in 11% of patients. None of the patients in our series had aneurysm of the left coronary sinus. Twenty eight of the 34 RCS aneurysms ruptured into the right ventricular outflow tract (RVOT), 4 into right ventricular cavity (RVC), one into right atrium (RA) and one dissected into the ventricular septum and subsequently ruptured into the left ventricle. Of the 4 NCS aneurysms, 2 ruptured into RVC, one into RA and one into both the RA and RVC. Associated ventricular septal defect (VSD) was found in 10 (26%) patients and all of these patients had RCS aneurysm that ruptured into the RVOT. Aortic regurgitation (AR) was detected in 16 (42%) cases. Discrete subaortic stenosis was detected in one patient who also had associated VSD and AR. Vegetation of the aortic valve was detected in one patient who had RCS aneurysm. Twelve patients (11 male and one female) underwent surgical correction, 10 with and 2 without prior catheterization. Localization of the involved sinus, site of rupture and associated cardiac lesions by echocardiography and doppler study were found accurate at surgery and/or angiography in 22 cases of our series. Imaging techniques, thus appeared to be reliable tools for the diagnosis of RASV.
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Khan MN. The relief of mitral stenosis. An historic step in cardiac surgery. Tex Heart Inst J 1996; 23:258-65; discussion 265-6. [PMID: 8969024 PMCID: PMC337096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Significant progress has been achieved in cardiac surgery in the last 50 years. Mitral valve surgery (especially for the relief of mitral stenosis) has paralleled the innovations and trends of cardiac surgery and often has served as the benchmark of the latest procedures and techniques. A chronological survey of mitral valve surgery is presented, with emphasis on parallels to cardiac surgery in general and with highlights of key figures and events that have conclusively altered the surgeon's approach to and success with cardiac dysfunction. A few surgeons promulgated the idea of cardiac surgery in the late 19th century, but mitral valve surgeries were not performed in earnest until Souttar's and Cutler's initial attempts in the 1920s and were not successful on large groups of patients until Bailey and Harken made independent breakthroughs in the 1940s, finally laying to rest the idea of the "inviolable heart." Cardiopulmonary bypass provided cardiac surgeons with the time to implant mechanical and bioprosthetic valves for palliative benefit to patients. The "perfect" valve has yet to be found, but the Starr-Edwards mechanical valve since its inception in 1961 has been one of the most successful and widely used prosthetic valves. Gradual improvement in surgical technique and growing knowledge of valve function enabled the re-emergence of mitral valve repair in the 1980s as the preferred surgical method of treating mitral stenosis. In the last 10 years, mitral valve balloon dilation has provided a nonsurgical technique for relief of stenosis and represents the broader trend towards interventional techniques.
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Khan MN, Kuliya-Umar AF. Kinetics and mechanism of general acid-catalysed thiolytic cleavage of 9-anilinoacridine. Bioorg Med Chem 1995; 3:881-90. [PMID: 7582964 DOI: 10.1016/0968-0896(95)00074-q] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The rates of the reactions of 2-mercaptoethanol (2-ME) with 9-anilinoacridine (9-ANA) have been studied in the buffer solutions of 2-ME, hydroxylamine, phosphate and morpholine. Both ionised and non-ionised forms of 2-ME and free hydroxylamine show nucleophilic reactivity toward protonated 9-ANA. The rate constants for general acid-catalysed thiolytic cleavage of protonated 9-ANA reveal a Brønsted plot of slope (alpha) of 0.93 which indicates that probably the rate-determining step involves proton transfer in a thermodynamically unfavourable direction. A stepwise mechanism for thiolysis has been suggested. General acid catalysis could be detected for thiolysis of non-protonated 9-ANA only in the buffer solutions of phosphate and morpholine. General acid catalysis seems to be unimportant when the nucleophile is non-ionised 2-ME which is attributed to the probable occurrence of intramolecular general acid catalysis.
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Abstract
The hydroxide ion-catalyzed hydrolysis of securinine involves the ring opening of the lactone moiety. The rate of hydrolysis is insensitive to the ionic strength. The observed pseudo-first-order rate constants reveal a decrease of approximately 4-fold due to the increase in the MeCN content from 4 to 50% (v/v) in mixed aqueous solvent. The temperature dependence of the rate of hydrolysis follows the Eyring equation, which yields delta H* and delta S* as 11.0 kcal mol-1 and -34.5 cal deg-1 mol-1, respectively. The hydroxyl carboxylate product of the alkaline hydrolysis of securinine is shown to undergo cyclization in acidic medium to yield securinine. The observed pseudo-first-order rate constants for cyclization increase linearly with an increase in [H+]. The change in the content of MeCN from 3.8 to 47.2% (v/v) in mixed aqueous solvents does not show an effect on the rate of the cyclization reaction. The most plausible mechanisms for alkaline hydrolysis and acid cyclization reactions are also discussed.
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73
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Ahmad HR, Khan MA, Memon M, Khan MN. Volume history response of airway resistance. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1995; 393:111-5. [PMID: 8629465 DOI: 10.1007/978-1-4615-1933-1_23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
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74
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Lajis NH, Abdullah AS, Salim SJ, Bremner JB, Khan MN. Epi-sarsasapogenin and epi-smilagenin: two sapogenins isolated from the rumen content of sheep intoxicated by Brachiaria decumbens. Steroids 1993; 58:387-9. [PMID: 8212090 DOI: 10.1016/0039-128x(93)90043-m] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Spectroscopic examination of purified extracts of the rumen content of sheep intoxicated by Brachiaria decumbens revealed the presence of two spirostanes, identified as epi-sarsasapogenin and epi-smilagenin. Sarsasapogenone was obtained by the oxidation of sarsasapogenin. The reduction of sarsasapogenone using lithium aluminum hydride yielded isomeric products, sarsasapogenin (20%) and epi-sarsasapogenin (80%).
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75
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Khan MN, Nizami SS, Khan MA, Ahmed Z. New saponins from Mangifera indica. JOURNAL OF NATURAL PRODUCTS 1993; 56:767-770. [PMID: 8326325 DOI: 10.1021/np50095a016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Two new terpenoidal saponins, indicoside A [1] and indicoside B [2], were isolated from Mangifera indica. Their structures were determined as 28-hydroxylupa-12,20(29)-diene-3-O-[beta-glucopyranosyl-(1-->2)] [-beta-glucopyranosyl-(1-->3)]-alpha-L-arabinopyranoside [1] and 28-hydroxylupa-12,20(29)-diene-3-O-[beta-glucopyranosyl-(1-->3)-al pha-L-rhamnopyranosyl-(1-->2)][beta-glucopyranosyl(1-->3)]-alpha-L- arabinopyranoside [2] on the basis of chemical and spectroscopic studies.
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76
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Khan MN, Lai WH, Burgess JW, Posner BI, Bergeron JJ. Potential role of endosomes in transmembrane signaling. Subcell Biochem 1993; 19:223-54. [PMID: 8385820 DOI: 10.1007/978-1-4615-3026-8_8] [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: 01/30/2023]
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77
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Burgess JW, Wada I, Ling N, Khan MN, Bergeron JJ, Posner BI. Decrease in beta-subunit phosphotyrosine correlates with internalization and activation of the endosomal insulin receptor kinase. J Biol Chem 1992; 267:10077-86. [PMID: 1374397] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
In a previous study, we showed that the rat hepatic insulin receptor (IR) kinase of endosomes (ENs) was transiently activated to levels exceeding those of plasma membrane (PM) receptors following insulin injection. Phosphatase treatment of EN receptors abolished IR kinase activation implicating beta-subunit autophosphorylation as a mediator of the activation process (Khan, M. N., Baquiran, G., Brule, C., Burgess, J., Foster, B., Bergeron, J. J. M., and Posner, B. I. (1989) J. Biol. Chem. 264, 12931-12940). In the present study, the phosphotyrosine (PY) content of the IR beta-subunit in PM and ENs was estimated by two different methods. In one method, direct in vivo labeling with 32Pi followed by receptor immunoprecipitation was carried out. In the second method, immunoblotting with antibodies against the submembrane domain of the IR beta-subunit, encompassing residue 960 (alpha 960), and with antibodies against PY (alpha PY) was used to determine the content of PY/beta-subunit in PM and ENs following injection of insulin. By both methods, it was found that the PY content of PM IR was significantly greater than that of IR in ENs. With doses of 1.5 micrograms of insulin/100 g body weight (50% receptor occupancy) or 15 micrograms/100 g body weight (receptor saturation), the PY/beta-subunit of PM IR attained a level 2.0 to 2.5-fold of that observed for the IR of ENs. Surprisingly, the IR of ENs incorporated 3 to 5 times more PY/beta-subunit than those of PM consequent to autophosphorylation. Exogenous IR kinase activity (poly(Glu:Tyr)) in PM changed only slightly with insulin dose. In contrast, EN receptors exhibited a dose-dependent increase in kinase activity coincident with the decrease in PY/beta-subunit levels. A comparison of the proportion of receptor and kinase activity immunoprecipitated by alpha PY both before and after autophosphorylation indicated that ENs but not PM contained a small population of lightly phosphorylated but highly activated receptors. Since Thr12-Lys (IR kinase residues 1142-1153) efficiently inhibited IR autophosphorylation of both PM and EN receptors, Tris phosphorylation of beta-subunit regulatory tyrosines was unlikely. These results may be explicable by a dephosphorylation-dependent activation of IR kinase, as seen with the src family of tyrosine kinases.
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Ali SM, Paramanik MA, Khan MN, Samad A. Assessment of low attendance at primary health care centre. BANGLADESH MEDICAL RESEARCH COUNCIL BULLETIN 1991; 17:81-7. [PMID: 1841596] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The study was conducted at 11 (eleven) randomly selected villages of Rupganj Upazila in order to find out the way to promote Primary Health Care. 1186 household heads and 11 physicians interviewed for the purpose. The study revealed that more than 54.14 percent of the study population were suffering from various diseases and only 4 percent of the patients attended Primary Health Care Centre/Complex. 52% of the patients were not satisfied by the service of Primary Health Care Centre/Complex. Want of medicine, lack of good physicians and doctors, carelessness about the patients constituted the principal causes of unsatisfactory treatment. The comparative distribution of opinion of household heads and physicians about non-attendance to Primary Health Care Centres by patients is statistically insignificant (P less than 0.05) which implies that the opinions are more or less the same. Both household heads and physicians opined that supply of sufficient medicine, equipment, improvement of health education and more budget allocations are essential to make the Primary Health Care service effective.
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Kachra Z, Barash I, Yannopoulos C, Khan MN, Guyda HJ, Posner BI. The differential regulation by glucagon and growth hormone of insulin-like growth factor (IGF)-I and IGF binding proteins in cultured rat hepatocytes. Endocrinology 1991; 128:1723-30. [PMID: 1706258 DOI: 10.1210/endo-128-4-1723] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The liver is a major site of production of insulin-like growth factor-I (IGF-I) and IGF binding proteins (IGF-BPs). GH decisively influences IGF-I production. To study the role of GH and glucagon in the regulation of IGF-I and IGF-BP production, we examined IGF-I and IGF-BPs secreted by primary rat hepatocytes cultured in a serum-free medium. Glucagon (1 x 10(-8) M) stimulated IGF-I secretion and IGF-BP secretion. Bovine GH (bGH, 300 ng/ml) stimulated IGF-I secretion but suppressed IGF-BP secretion. Combining bGH and glucagon significantly augmented IGF-I secretion above the level seen with each individual agent. The inhibitory effect of bGH on IGF-BP secretion was reversed by glucagon. The major species of IGF-BPs secreted by hepatocytes were found, on Western ligand blotting, to be 24K and 30-34K. All species of secreted IGF-BPs appeared to be comparably affected by glucagon, bGH, and their combination. Northern analysis of IGF-I mRNA revealed three transcripts of 0.7-1.1 kilobases (kb), 1.8 kb, and 7.0 kb. Glucagon stimulated IGF-I mRNA levels 1.8- to 2.0-fold, whereas bGH stimulated IGF-I mRNA levels 2.0- to 2.5-fold. When hepatocytes were incubated with glucagon and bGH for 6 h, IGF-I mRNA levels were augmented 10-fold. Glucagon, in the presence of 50 ng/ml bGH, had a dose-dependent effect on IGF-I mRNA accumulation from a 6-fold level of stimulation at 50 ng/ml of glucagon to a 9-fold level of stimulation at 1000 ng/ml glucagon to a 9-fold level of stimulation at 1000 ng/ml glucagon. This study has demonstrated that glucagon, as well as GH, has significant effects on the production of both IGF-I and IGF-BPs. Of particular interest was the marked augmentation of hepatic IGF-I messenger RNA levels and the reversal of the low levels of IGF-BP production seen on adding glucagon to bGH.
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80
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Khan MN, Ahmad SH, Fakhir S. Comparison of temperatures at different sites in term and pre-term neonates. Indian Pediatr 1990; 27:807-9. [PMID: 2279803] [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
Temperatures of 30 term and 20 preterm neonates were recorded by mercury-in-glass thermometer at 4 measurement sites; rectum (2 cm beyond anus), external auditory canal, axilla and between skin and mattress. Whereas, the mean rectal and aural temperatures in term infants were significantly higher than their preterm counterparts (p less than 0.01), axillary and skin mattress temperatures did not differ significantly in the two groups. The variation between stabilized temperature at four measurement sites was less marked in preterm as compared to term infants. The skin mattress temperature measurement is a simpler technique and it closely approximates the rectal temperature in preterm infants. Temperatures at all the measurement sites stabilized by 5 minutes both in term and preterm infants.
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81
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Chowdhury MM, Bhuyan MA, Khan MN, Ahmed N, Malek MA. Effect of retraining on nutrition among tribal women volunteers in Bangladesh. BANGLADESH MEDICAL RESEARCH COUNCIL BULLETIN 1989; 15:73-80. [PMID: 2629698] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Training programme on Nutrition was carried out on 42 tribal women nutrition volunteers from Rangamati, Khagrachari and Banderban districts of Chittagong Hill Tracts during July 1987 to June 1988. There were a basic training for 10 days and five retrainings of 6 days on the same group. Assessments on the level of their knowledge before and after each training were conducted by a standard questionnaire. Mean score obtained by the trainees initially was 46.28% which increased to 97.23% in the last round. Although the knowledge gain was found statistically significant in each retraining but the retention of knowledge in pre-test of each retraining was found statistically significant (P less than 0.001) upto second round (i.e. 1st retraining) and thereafter the retention was found insignificant (P greater than 0.05).
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82
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Khan MN, Baquiran G, Brule C, Burgess J, Foster B, Bergeron JJ, Posner BI. Internalization and activation of the rat liver insulin receptor kinase in vivo. J Biol Chem 1989; 264:12931-40. [PMID: 2546941] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The preparation of clearly delineated plasmalemma (PM) and endosomal subcellular fractions from rat liver has allowed us to compare insulin receptor (IR) kinase activity at the cell surface and in hepatic endosomes (ENs) as a function of dose and time after injected insulin. Tyrosine kinase activity in PM and ENs was measured, after solubilization and partial purification by wheat germ agglutinin chromatography (lectin-purified), using poly(Glu:Tyr) as substrate. Following the injection of a subsaturating dose of insulin (1.5 micrograms/100 g body weight), lectin-purified receptor showed peak activation at 30 s in PM and at 2 min in ENs. As observed previously (Khan, M. N., Savoie, S., Bergeron, J. J. M., and Posner, B. I. (1986) J. Biol. Chem. 261, 8462-8472) autophosphorylation activity was also augmented following insulin injection. In a pattern virtually identical to that of exogenous kinase activity, autophosphorylation attained peak activity at 30 s in PM and at 2 min in ENs. The time course of IR autophosphorylation in intact membranes was very similar to that observed for lectin purified receptors and was seen with an injected insulin dose as low as 150 ng/100 g body weight. Phosphatase treatment of the solubilized endosomal receptor abolished its enhanced activity. Hence, insulin treatment led to in vivo receptor phosphorylation which was reflected in the enhancement of both tyrosine kinase and autophosphorylation activities. Significant differences in the phosphorylation activities of PM and ENs were observed. Phosphoamino acid analyses revealed that the activated IR of intact PM was autophosphorylated in vitro, at both serine (55%) and tyrosine (45%) residues; whereas the activated IR of intact ENs was phosphorylated in vitro exclusively on tyrosine autophosphorylation specific activity for the activated IR of ENs was 3- to 4-fold that of the IR of PM. This was observed for the lectin purified IRs as well as for IRs of intact cell fractions. The reduced level of IR autophosphorylation in PM was not due to occlusion of tyrosine acceptor sites by prior in vivo phosphorylation. The rapidity with which activated IR accumulates in ENs as well as the sensitivity of endosomal IR kinase to activation by injected insulin are consistent with the endosomal apparatus serving a physiologically significant site for the regulation of transmembrane signaling.
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83
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Shamsi Z, Anwar MA, Khan MN. Fine needle percutaneous transhepatic cholangiogram (PTC). J PAK MED ASSOC 1989; 39:219-21. [PMID: 2509758] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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84
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Khan MN, Baquiran G, Brule C, Burgess J, Foster B, Bergeron JJ, Posner BI. Internalization and Activation of the Rat Liver Insulin Receptor Kinase in vivo. J Biol Chem 1989. [DOI: 10.1016/s0021-9258(18)51577-5] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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85
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Abstract
Experience of 189 patients with non-specific ulcerative colitis has been reviewed. The majority of patients was in the 21-30 year age group, and neither sex predominated. Seventy-two percent had mild to moderate disease. The disease was mainly confined to the left colon (60%) and 13% had total colitis.
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86
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Khan MN. Aqueous degradation of N-(hydroxymethyl)phthalimide in the presence of specific and general bases. Kinetic assessment of N-hydroxymethyl derivatives of nitrogen heterocycles as possible prodrugs. J Pharm Biomed Anal 1989; 7:685-91. [PMID: 2490772 DOI: 10.1016/0731-7085(89)80112-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The conversion of N-(hydroxymethyl)phthalimide (NHPH) to phthalimide could not be detected within 300 s at pH 9.0, whereas in 0.18 M NaOH complete conversion of NHPH to phthalimide was observed within 50 s. In the presence of 0.2-0.4 M 1,4-diazabicyclo[2.2.2]octane buffer solutions (pH 9.30-9.54), 40-60% conversion of NHPH to phthalimide occurred within 90-120 s. The initial concentration of NHPH affected the extent of conversion of NHPH to phthalimide.
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87
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Barenton B, Patel BA, Khan MN, Guyda HJ, Posner BI. Insulin-like growth factor-binding proteins in hypophysectomized rat liver: characterization and subcellular localization. Endocrinology 1988; 122:2499-507. [PMID: 2967175 DOI: 10.1210/endo-122-6-2499] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
We have characterized binding proteins for insulin-like growth factors (IGFs) in hepatic subcellular fractions and in the washed supernatants of these fractions in normal and hypophysectomized (hypox) rats. In the course of assessing IGF-II-binding sites on rat liver microsomes, we observed that [125I] IGF-II binding to the microsomal membranes of hypox rats was much lower than that in normal rats. Paradoxically, binding increased in hypox animals at low concentrations (0.5-5 ng/ml) of unlabeled IGF-II. After resuspension and centrifugation (washing) of the microsomes, no difference was found in [125I]IGF-II binding to hypox vs. normal microsomes. However, the binding of [125I]IGF-II to the washing supernatant (SN) from hypox rat microsomes was greater than binding to that from normal animals. Binding to SN was inhibited by unlabeled IGF-II in a dose-dependent manner. Scatchard analyses indicated that the affinity constant for binding by hypox SN was higher than that of normal SN and the microsomal fractions of both hypox and normal rats. After further subfractionation of the liver, no binding activity was found in SN from plasmalemma, whereas it was about 20% of input counts per min of [125I]IGF-II in SN from combined Golgi-endosome fractions of hypox rat liver. We next compared IGF-binding moieties in microsomal SN with those in plasma using cross-linking of [125I]IGF-II followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. In normal rat plasma, we observed the presence of 42K, 39K, 31K, and 27K binding complexes. In hypox rat plasma only a 42-39K doublet was found. In the SN of normal rat microsomes, the predominant complex migrated at 39K and was distinguishable only after acidification. In the SN of hypox rat microsomes, the 42K complex was predominant, with a minor 34K complex. These studies have identified IGF-binding moieties in hepatic tissues, particularly in hepatic vesicular elements, which interfere in the binding of IGF-II to membrane receptors. Their presence in these receptor-rich elements may influence IGF binding to intracellular receptors and, hence, the biological activity of the peptide.
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88
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Bergeron JJ, Lai WH, Kay DG, Doherty JJ, Khan MN, Posner BI. The endosomal apparatus and transmembrane signalling. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1988; 234:213-24. [PMID: 3063087 DOI: 10.1007/978-1-4757-1980-2_14] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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89
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Khan MN. Spectrophotometric determination of alkyl salicylate from the mixture of phenyl and alkyl salicylates by the use of the selective reactivity of phenyl salicylate toward secondary amines. J Pharm Biomed Anal 1987; 5:515-21. [PMID: 16867496 DOI: 10.1016/0731-7085(87)80061-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/1986] [Revised: 02/10/1987] [Indexed: 11/23/2022]
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90
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Khan MN, Savoie S, Bergeron JJ, Posner BI. Differential kinetics and sensitivity to chloroquine of receptor-mediated insulin and prolactin endocytosis in liver parenchymal cells. BIOCHIMICA ET BIOPHYSICA ACTA 1986; 888:100-6. [PMID: 3017440 DOI: 10.1016/0167-4889(86)90075-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Systemically injected [125I]prolactin or [125I]insulin was accumulated and cleared from rat liver at different rates. Quantitative subcellular fractionation indicated a predominant accumulation of [125I]insulin in liver microsomes while [125I]prolactin was found in both the light-mitochondrial and microsomal fractions. The acidotropic agent chloroquine diminished the rate and extent of loss of each ligand from liver homogenates. In chloroquine treated rats, radiolabeled insulin accumulated in both the light-mitochondrial and the microsomal fractions. Subfraction of microsomes on discontinuous sucrose gradients revealed "early' endosomes in which ligand uptake was maximal at 2-5 min. In contrast, comparable subfraction of the of light mitochondrial fraction revealed "late' endosomes in which ligand uptake was maximal at 10-20 min. Chloroquine-treated rats showed a more marked enhancement of insulin compared to prolactin uptake in the "early' endosomes. It is suggested that "early' endosomes found in the Golgi-intermediate and -heavy fractions floated from parent microsomes may selectively degrade insulin but not prolactin. This could account for the apparently different kinetics of insulin and prolactin uptake into liver parenchyma.
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91
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Kay DG, Lai WH, Uchihashi M, Khan MN, Posner BI, Bergeron JJ. Epidermal growth factor receptor kinase translocation and activation in vivo. J Biol Chem 1986; 261:8473-80. [PMID: 2424897] [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] Open
Abstract
The rat liver epidermal growth factor (EGF) receptor was assessed for EGF-dependent autophosphorylation as well as phosphorylation of a defined exogenous substrate in purified plasmalemma and Golgiendosome fractions isolated from rat liver homogenates. While EGF-dependent kinase activity was readily detected in plasmalemma the corresponding activity in Golgi-endosome fractions required detergent. Consequent to the systemic injection of EGF in vivo, the majority (approximately 60%) of receptor as evaluated by 125I-EGF binding was rapidly lost (T 1/2 approximately 8 min) from the plasmalemma and correspondingly accumulated in the Golgi-endosome fraction in a dose-dependent manner. Electron microscope radioautography of 125I-EGF uptake into Golgi-endosome fractions identified internalization into lipoprotein-filled vesicles of heterogenous size and shape but not into stacked saccules of the Golgi apparatus. Evaluation of receptor kinase activity in plasmalemma fractions isolated at various times after EGF injection in vivo showed more rapid loss of EGF-dependent autophosphorylation activity (T 1/2 approximately 10 s) than of receptor content (T 1/2 approximately 8 min). In contrast to the EGF receptor kinase of the plasmalemma fraction, kinase activity accumulating in endosomes was activated, i.e. maximally stimulated, in the absence of EGF or Triton X-100 in vitro. Furthermore, following the peak time of accumulation of EGF receptor kinase in endosomes (5-15 min) EGF-dependent autophosphorylation activity and EGF receptor content were lost more slowly (T 1/2 approximately 27 and 87 min for the loss of autophosphorylation activity and receptor content, respectively). The rapidity of translocation of activated EGF receptor into endosomes (30 s) and the dose response to low levels (1 microgram) of EGF injected are consistent with a physiological role for internalized EGF receptor kinase activity.
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92
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Khan MN, Savoie S, Bergeron JJ, Posner BI. Characterization of rat liver endosomal fractions. In vivo activation of insulin-stimulable receptor kinase in these structures. J Biol Chem 1986; 261:8462-72. [PMID: 3522569] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
A protocol employing discontinuous sucrose gradient centrifugation was developed to prepare light mitochondrial (L) and Golgi fraction endosomes from simultaneously prepared parent L and microsomal fractions. As judged by the concentration of labeled hormone postinjection, L intermediate and heavy endosome subfractions were 40- to 175-fold purified and Golgi intermediate and heavy endosome subfractions were 30- to 45-fold purified. On electron microscopy, L endosomal fractions contained a predominance of lipoprotein-filled vesicles and were less heterogeneous than corresponding Golgi endosomal fractions. All endosomal fractions were enriched in receptors for insulin and prolactin but binding sites for the former were more broadly distributed in other subfractions than those for the latter. On Percoll gradient centrifugation, L endosomal fractions yielded one peak (rho 1.057) corresponding to the heavier of two peaks seen in Golgi endosomal fractions. The protein composition of high density L and Golgi endosomes, as assessed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, was similar. The bulk of marker enzymes assayed did not migrate with the endosomal components. Combined acid phosphatase cytochemistry and electron microscope radioautography established that about 80% of the L endosomes contained no acid phosphatase. By affinity labeling and immunological titration with insulin receptor antibody, insulin receptors were identical in L and Golgi endosomes. Insulin-stimulable receptor kinase was demonstrable in both L and Golgi endosome fractions. Following in vivo insulin administration, the insulin receptor kinase in both L and Golgi endosomes was significantly activated. This activated state was not inhibited by a large excess of antiserum to insulin and thus not due to insulin contaminating the partially purified receptor preparation. These observations are compatible with the maintenance and/or initiation of hormone-dependent phosphorylations intracellularly.
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93
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Bergeron JJ, Searle N, Khan MN, Posner BI. Differential and analytical subfractionation of rat liver components internalizing insulin and prolactin. Biochemistry 1986; 25:1756-64. [PMID: 3011072 DOI: 10.1021/bi00355a046] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Receptor-mediated endocytosis of 125I-insulin and 125I-prolactin into liver parenchymal cells has been studied by quantitative subcellular fractionation. Differential centrifugation yielded three particulate fractions, N (nuclear), ML (large granule), and P (microsomes), and a final supernatant (S). Quantitative differences in the extent and rates of accumulation of 125I-insulin and 125I-prolactin into the fractions were observed. The acidotropic agent chloroquine and the microtubule disrupting agent colchicine were administered separately to rats. The agents increased significantly the T 1/2 of hormone clearance from the liver and augmented the accumulation of both ligands in the low-speed ML fraction. However, differences in the rates of accumulation of insulin and prolactin into all cell fractions were still maintained. Analytical centrifugation of each of the particulate fractions was carried out in order to determine if different endocytic components were specific to insulin or prolactin internalization. This was not the case. An "early" endosomal component of density 1.11 was identified in microsomes. A "late" endosome of density 1.10 was identified in the large granule (ML) fraction. Both endosomal components appeared to accumulate insulin and prolactin but at different rates. Marker enzyme analysis identified the presumed plasma membrane component in microsomes (density approximately 1.155). This component showed a significant difference in the rate of loss of 125I-insulin (T 1/2 approximately 4.1 min) as compared to that of 125I-prolactin (T 1/2 approximately 12.7 min). A further difference in the handling of the ligands was observed in early endosomes.(ABSTRACT TRUNCATED AT 250 WORDS)
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Posner BI, Khan MN, Kay DG, Bergeron JJ. Internalization of hormone receptor complexes: route and significance. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1986; 205:185-201. [PMID: 3024469 DOI: 10.1007/978-1-4684-5209-9_9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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95
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Bergeron JJ, Paiement J, Khan MN, Smith CE. Terminal glycosylation in rat hepatic Golgi fractions: heterogeneous locations for sialic acid and galactose acceptors and their transferases. BIOCHIMICA ET BIOPHYSICA ACTA 1985; 821:393-403. [PMID: 2934093 DOI: 10.1016/0005-2736(85)90043-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Endogenous acceptors for N-acetylglucosamine (GlcNAc), galactose (Gal) or sialic acid (NeuAc) transfer were labeled to high activities when purified hepatic Golgi fractions were incubated with the corresponding radiolabeled nucleotide sugar in the absence of detergent. The in vitro conditions which were optimal for the endogenous glycosylation of GlcNAc and Gal acceptors (Mn2+, ATP) also promoted fusion within a subset of Golgi membranes. Electron microscope radioautography revealed that the majority of NeuAc acceptors were associated with unfused Golgi membranes, whereas the majority of Gal acceptors were localized to fused membranes. GlcNAc acceptors were approximately equally distributed between fused and unfused membranes. Under conditions in which Golgi membrane fusion was absent (-Mn2+), only NeuAc transfer was active. The majority of endogenous NeuAc acceptors were consequently assigned to the more trans regions of the hepatic Golgi apparatus as concluded from a combination of radioautography (NeuAc transfer) and acid NADPase cytochemistry (reactive medial and trans Golgi saccules). The distribution of NeuAc and Gal transferases was assessed after Percoll gradient centrifugation of disrupted Golgi fractions. The median density of NeuAc transferase was lower than that of Gal transferase. The studies are indicative of distinct Golgi components harboring the majority of acceptors and enzymes for terminal glycosylation.
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Bergeron JJ, Cruz J, Khan MN, Posner BI. Uptake of insulin and other ligands into receptor-rich endocytic components of target cells: the endosomal apparatus. Annu Rev Physiol 1985; 47:383-403. [PMID: 2986535 DOI: 10.1146/annurev.ph.47.030185.002123] [Citation(s) in RCA: 139] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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Khan MN, Savoie S, Khan RJ, Bergeron JJ, Posner BI. Insulin and insulin receptor uptake into rat liver. Chloroquine action on receptor recycling. Diabetes 1985; 34:1025-30. [PMID: 3899805 DOI: 10.2337/diab.34.10.1025] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
In the present study, the effect of chloroquine on both insulin and receptor distribution was examined in vivo. Insulin injection (25 nmol/100 g body wt) caused a marked accumulation of both insulin and its receptor in purified hepatic Golgi fractions by 15 min postinjection. Percoll fractionation of parent Golgi fractions resolved two endocytic components of low (rho = 1.040-1.050) and high (rho = 1.053-1.064) density in which the relative distribution of insulin binding sites was unaltered by chloroquine. Chloroquine significantly accumulated in the high-density region of the Percoll gradient consistent with this being a low pH compartment. 125I-insulin accumulated first in the low-density (1 min) and subsequently in the high-density region (5-10 min) of Percoll-subfractionated Golgi fractions. Chloroquine treatment caused marked accumulation of 125I-insulin in the high-density compartment with substantial retention of radiolabel therein at 20 min postinjection. 125I-insulin extracted from the Percoll fractions was comparably intact in control and chloroquine-treated rats. These data suggest that the chloroquine-accumulating, high-density compartment of hepatic Golgi fractions is the site of dissociation of internalized insulin-receptor complexes before degradation of the ligand and receptor recycling.
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Khan RJ, Khan MN, Bergeron JJ, Posner BI. Prolactin uptake into liver endocytic components. Reduced sensitivity to chloroquine. BIOCHIMICA ET BIOPHYSICA ACTA 1985; 838:77-83. [PMID: 2981568 DOI: 10.1016/0304-4165(85)90252-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Subfractionation of hepatic Golgi fractions on Percoll gradients revealed two populations of lactogen-receptor enriched components with one pool of rho = 1.040-1.050 and a high-density component of rho = 1.053-1.064. 125I-labelled prolactin uptake into Percoll gradient subfractions demonstrated rapid accumulation into low-density elements and slower accumulation in high-density structures. Electron microscope radioautography demonstrated that silver grains were largely associated with lipoprotein-filled structures. Radiolabel was highly concentrated in these components especially the very pure higher-density component where enrichment over the homogenate was 184-fold at the peak time after injection (10 min). Administered chloroquine accumulated in the higher-density component but not in low-density elements, suggesting that the former are at an acid intraluminal pH. In contrast to the marked effect of chloroquine on insulin uptake into endocytic structures found in Golgi fractions (Posner, B.I., Patel, B.A., Khan, M.N. and Bergeron, J.J.M. (1982) J. Biol. Chem. 257, 5789-5799), little effect of this pH disrupting agent was observed on prolactin uptake. The difference between the effect of chloroquine on 125I-labelled prolactin and 125I-labelled insulin uptake may reflect the greater stability of prolactin-receptor complexes in a low-pH environment.
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Posner BI, Khan MN, Bergeron JJ. Peptide hormone receptors in intracellular structures from rat liver. Methods Enzymol 1985; 109:219-31. [PMID: 2985917 DOI: 10.1016/0076-6879(85)09088-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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Abstract
The kinetics of hydrolysis of maleimide was carried out within the [OH-] range of 2.46 X 10(-6) to 2.0 M at 30 degrees C. The observed pseudo-first-order rate constants, kobs, follow the empirical equation: kobs = (A1[OH-] + A2[OH-]2)/(1 + A3[OH-]). Both ionized and un-ionized forms of maleimide have been suggested to be involved in hydrolysis. The nucleophilic attacks by hydroxide ion at the carbonyl carbon of both ionized and un-ionized maleimide and by water at the carbonyl carbon of ionized maleimide to form tetrahedral intermediates are considered to be the rate-determining steps. The observed results obtained at different 1,4-dioxane-water compositions have revealed an increase in kobs with a decrease in 1,4-dioxane content which could be attributed to the higher polarity of the transition state compared with the reactant state.
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