651
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Khan SA, Merkel GJ, Becker JM, Naider F. Synthesis of the dodecapeptide-alpha mating factor of Saccharomyces cerevisiae. INTERNATIONAL JOURNAL OF PEPTIDE AND PROTEIN RESEARCH 1981; 17:219-30. [PMID: 7014484 DOI: 10.1111/j.1399-3011.1981.tb01985.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The synthesis of His-Trp-Leu-Gln-Leu-Lys-Pro-Gly-Gln-Pro-Met-Tyr, the dodecapeptide alpha-mating factor from Saccharomyces cerevisiae, and its Ala2- and Cha2-(beta-cyclohexylalanine) analogs are reported. Peptides were synthesized in solution using a combination of mixed anhydride and 1-hydroxybenzotriazole accelerated active ester coupling procedures. Dilute methanesulfonic acid (0.1-0.2 M) in methylene chloride-formic acid solution was employed to specifically remove the tert.-butoxycarbonyl group in the presence of the benzyloxycarbonyl group. Free peptides were obtained using catalytic transfer hydrogenation with formic acid as the hydrogen donor followed by mild acidolysis with trifluoroacetic acid. The alpha-factor and the Cha2-analog exhibited almost equal ability to cause "shmooing" of a-mating types of S. cerevisiae whereas the Ala2-analog exhibited no activity in this assay. These results differ with structure-activity studies reported on the tridecapeptide alpha-factor.
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652
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Novick RP, Khan SA, Murphy E, Iordanescu S, Edelman I, Krolewski J, Rush M. Hitchhiking transposons and other mobile genetic elements and site-specific recombination systems in Staphylococcus aureus. COLD SPRING HARBOR SYMPOSIA ON QUANTITATIVE BIOLOGY 1981; 45 Pt 1:67-76. [PMID: 6271492 DOI: 10.1101/sqb.1981.045.01.013] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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653
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Khan SA, Novick RP. Terminal nucleotide sequences of Tn551, a transposon specifying erythromycin resistance in Staphylococcus aureus: homology with Tn3. Plasmid 1980; 4:148-54. [PMID: 6100928 DOI: 10.1016/0147-619x(80)90004-9] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The erythromycin resistance determinant of Staphylococcus aureus plasmid pI258 resides on a 5.3 kb transposon, Tn551. We have determined DNA sequences surrounding the junctions between the transposon and the flanking DNA in the wild-type plasmid, in an insertion into a second plasmid, and in two transposon-related deletions. The ends of the transposon consist of an inverted repeat of 40 base pairs flanked by a direct repeat of 5, thus placing the transposon in the same class as Tn3, IS2, Tn501, gamma delta, and bacteriophage Mu. Interestingly, we find that the terminal sequences of the 40 base pairs inverted repeat are very similar to the ends of Tn3, a transposon which one would not have expected to show any relation to Tn551. This result suggests common ancestry for Tn3 and Tn551. The inverted repeat sequence of Tn551 also contains (with one additional inserted base) the internal heptanucleotide sequence which has been found to be common to most of the transposable elements that generate 5-base pair direct repeat sequences.
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654
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Naider F, Khan SA, Parker DD, Becker JM. Inhibition of oligopeptide transport in S. cerevisiae by a peptide-poly (ethylene glycol) conjugate. Biochem Biophys Res Commun 1980; 95:1187-91. [PMID: 6998475 DOI: 10.1016/0006-291x(80)91598-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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655
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Sahai Srivastava BI, Khan SA, Minowada J, Henderson ES, Rakowski I. Terminal deoxynucleotidyl transferase activity and blast cell characteristics in adult acute leukemias. Leuk Res 1980; 4:209-15. [PMID: 7412359 DOI: 10.1016/0145-2126(80)90080-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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656
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Bhanot OS, Khan SA, Chambers RW. A new system for studying molecular mechanisms of mutation by carcinogens. J Biol Chem 1979; 254:12684-93. [PMID: 227905] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
A new system for studying the molecular mechanisms of mutation by carcinogens is described. The system involves (a) site-specific modification of the essential gene G in phi X174 replicative form DNA by a combination of chemical and enzymatic steps; (b) production of mutant virus carrying a change at a single preselected site by transfection of spheroplasts with the site modified phi X174 DNA; (c) detection and propagation of mutants using a host carrying the plasmid, p phi XG, that rescues all type of gene G mutants by complementation; (d) identification of the mutation in the progeny virus by isolating and sequencing mutant phi X174 DNA in the region that carried the parental, site-specific change. To demonstrate that this system is operational, we have produced a previously unknown phi X174 gene G mutant carrying a C leads to T base change at position 2401 of the viral (plus) strand. This preplanned, nonsense (amber) mutant was obtained by changing G to A at the appropriate position in a chemically synthesized, octadeoxynucleotide, minus strand primer; elongating this enzymatically with Escherichia coli DNA polymerase I (larger fragment) (lacking 5' leads to 3' exonuclease activity) to a 17-mer; and repriming to obtain the site-modified phi X174 replicative form DNA enzymatically with E. coli DNA polymerase I (large fragment) and T4 DNA ligase. After transfection of spheroplasts with the heteroduplex DNA, the lysate was screened for mutant virus with permissive (carrying p phi XG) and nonpermissive (without p phi XG) host cells. About 1% of the progeny virus were mutants. Out of 15 isolates, 11 were suppressible by an amber Su1+ (serine) or an ochre Su8+ (glutamine) suppressor. The other 4 isolates were not suppressed at all. Replicative form DNA produced from one of the suppressible mutants was shown (by sequencing) to contain the expected C leads to T change at the preselected site in the viral strand. Replicative form DNA from one of the nonsuppressible mutants was partially sequenced. No change was found at or around position 2401. The nature of the mutation(s) in these isolates is still unknown. The occurrence of mutations outside the preselected sites represent a potential problem for our projected studies, but additional data is required before the problem can be fully evaluated. In spite of this, it should be possible to study, in vivo, the biological effects of any site-specific modification (including covalent modifications by carcinogens) that can be introduced into gene G of phi X174 DNA via a synthetic, oligonucleotide primer.
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657
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Prasad K, Singh B, Khan SA, Agarwala AK, Padmanabhan VS, Chatterjee AK. A case of bite by Krait snake. THE JOURNAL OF THE ASSOCIATION OF PHYSICIANS OF INDIA 1979; 27:1043-4. [PMID: 575720] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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658
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Prakash B, Singh B, Khan SA, Pahuja JM, Prasad K, Agarwal RK, Padmanabhan V, Chatterjee AK. Digitalis intolerance: case report. Indian Heart J 1979; 31:375-6. [PMID: 546726] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
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659
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Khan SA. Observations in the treatment of acne vulgaris with a povidone iodine skin cleanser. THE BRITISH JOURNAL OF CLINICAL PRACTICE 1979; 33:289-90. [PMID: 160799] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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660
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Baig MA, Khan SA. Effect of storage conditions on protein contents of different components of Indian buffalo blood. INDIAN JOURNAL OF BIOCHEMISTRY & BIOPHYSICS 1979; 16:332-4. [PMID: 540943] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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661
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Khan SA, Hasan M. Effect of various doses of lithium on the level of biogenic amines in discrete areas of rat brain. Indian J Med Res 1979; 69:489-94. [PMID: 447388] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
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662
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Srivastava BI, Khan SA, Song SY. Terminal deoxynucleotidyl transferase in hairy-cell leukaemia and Hodgkin's disease. Br J Cancer 1978; 38:643-4. [PMID: 728354 PMCID: PMC2009790 DOI: 10.1038/bjc.1978.264] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
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663
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Khan SA, Sivanandaiah KM. Solid-phase synthesis of oxytocin, desaminooxytocin and 4-Thr-oxytocin using active esters in presence of 1-hydroxybenzotriazole. INTERNATIONAL JOURNAL OF PEPTIDE AND PROTEIN RESEARCH 1978; 12:164-9. [PMID: 700921 DOI: 10.1111/j.1399-3011.1978.tb02880.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Using appropriate amino acid active esters (3 eq.) in presence of HOBt (1 eq.) and employing DPM protection for the thiol function of cysteine, a rapid synthesis of oxytocin in the solid phase has been accomplished. The DPM group has been removed by sodium-liquid ammonia reduction since boiling TFA is ineffective. Desaminooxytocin and 4-Thr-oxytocin have been synthesized using lesser quantities of amino acid active esters (1.5 eq.) in presence of HOBt (1 eq.), but the durations of coupling are longer. The solid-phase synthesis of desamino-oxytocin using appropriate Boc-amino acids in presence of DCCI in toluene medium has been described. Toluene does not exert any significant accelerating influence on the coupling rate as it does when active esters are employed.
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664
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Khan SA. Treatment of non-inflammatory dermatoses. A double-blind comparison of 1% hydrocortisone plus 10% urea and 0.05% fluocinonide. THE PRACTITIONER 1978; 221:265-7. [PMID: 364458] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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665
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Sahai Srivastava BI, Khan SA, Minowada J, Freeman A. High terminal deoxynucleotidyl transferase activity in pediatric patients with acute lymphocytic and acute myelocytic leukemias. Int J Cancer 1978; 22:4-9. [PMID: 277433 DOI: 10.1002/ijc.2910220103] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Specificity of TdT5 as a marker for ALL was evaluated by determining its activity in cells from normal control subjects and from 35 pediatric patients with ALL, AML, Hodgkin's disease and disseminated Burkitt's lymphoma. We evaluated the DNA polymerase activity, cell surface phenotypes (E rosettes, EAC rosettes, Smlg and la-like, HTLA and cALL antigens), and hematological and cytochemical characteristics in both the normal and patient groups. DNA polymerase alpha + beta and DNA polymerase gamma activity were indiscriminately high in all immature cells as found in ALL, AML, Burkitt's lymphoma and phytohemagglutinin-stimulated normal lymphocytes, when compared to mature leukocytes found in normal individuals or in patients whose cancer was in remission. High TdT activity was found in 24 of 26 T and non-T/non-B ALL patients in active phase as well as in two of three AML patients one of whom had Auer rods. Thus, TdT, although valuable for monitoring ALL patients, may have limitations in separating AML from ALL.
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666
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667
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Srivastava BI, Khan SA, Minowada J, Gomez GA, Rakowski I. Terminal deoxynucleotidyl transferase activity in blastic phase of chronic myelogenous leukemia. Cancer Res 1977; 37:3612-8. [PMID: 269010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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668
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Khan SA, Salahuddin A. Influence of pH, temperature & denaturant on the time course of the autodigestion of porcine pepsin. INDIAN JOURNAL OF BIOCHEMISTRY & BIOPHYSICS 1977; 14:202-5. [PMID: 25842] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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669
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Abstract
Antibodies to the deoxyribotrinucleotides dpApTpA and dpApApT were prepared by injecting the bovine serum albumin conjugates of the respective haptens in rabbits. The specificities of the antibodies were determined by estimating the inhibition of the binding of the tritiated haptens to the immunoglobulins by various nonradioactive mono- and oligonucleotides, using nitrocellulose membrane binding assay. Anti-dpApTpA and anti-dpApApT antisera were found to contain antibodies which were highly specific to the respective hapten sequence.
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670
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Khan SA, Humayun MZ, Jacob TM. Antibodies specific to a deoxyribodinucleotide sequence. Nucleic Acids Res 1977; 4:2997-3006. [PMID: 410004 PMCID: PMC342629 DOI: 10.1093/nar/4.9.2997] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Antibodies were raised in rabbits against the bovine serum albumin conjugate of dpApT. Analysis by double diffusion in agar gel and quantitative precipitation test showed the presence of antibodies specific to the hapten in the antisera. Quantitative data on the specificity of the antibodies were obtained by studying the inhibition of the binding of 3H-dpApT to the antisera by various nonradioactive mono- and oligonucleotides, using a nitrocellulose membrane binding assay. The antibodies were found to be highly specific for the dinucleotide sequence dpApT. The antibodies were able to bind to synthetic oligonucleotides containing the sequence dpApT and to denatured calf thymus DNA.
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671
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Khan SA, Williamson DM. A double-blind comparison of 1% hydrocortisone plus 10% urea ('Alphaderm') and 0.1% betamethasone 17-valerate in the treatment of non-infective inflammatory dermatoses. Curr Med Res Opin 1977; 5:354-8. [PMID: 343995 DOI: 10.1185/03007997709110192] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
A double-blind controlled trial was carried out over a period of 3 weeks to assess the effectiveness of 1% hydrocortisone, in a specialized carbamide drug delivery system, compared with 0.1% betamethasone 17-valerate cream in the treatment of 21 patients with bilateral, symmetrical, non-infective inflammatory dermatoses. The trial preparations were applied topically twice daily, each to one side only during the trial. Although overall patient preference tended to favour betamethasone 17-valerate, the physician's assessment of clinical improvement, based on severity rating scores, indicated that both preparations were equally effective and there were no significant differences between the calculated mean percentage clinical improvements at the end of each week.
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672
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Sahai Srivastava BI, Khan SA, Henderson ES. High terminal deoxynucleotidyl transferase activity in acute myelogenous leukemia. Cancer Res 1976; 36:3847-50. [PMID: 1085195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Although leukocytes from all 13 acute lymphoblastic leukemia patients examined had high terminal deoxynucleotidyl transferase (terminal transferase) activity (20 to 100 units/mg of cellular DNA, where 1 unit equals 1 nmole of nucleotide polymerized in 1 hr) and those from 21 acute myelocytic leukemia patients had low terminal transferase activity (0.2 to 2 units/mg of cellular DNA), the bone marrow and peripheral blood leukocytes from 2 patients with acute myelocytic leukemia, diagnosed on the basis of clinical features and the morphology, cytochemistry, and cytogenetics of the leukemic cells, had terminal transferase activity (39 to 52 units/mg of cellular DNA) equivalent to that found in leukemic lymphoblasts. These results bring under question the specificity of high terminal transferase activity outside of the thymus as a marker for leukemic lymphoblasts and, secondarily, the derivation of acute lymphoblastic leukemia cells in all cases from thymocytes. Perhaps malignant transformation in a pleuripotent stem cell with derepression of the genome for terminal transferase could account for high terminal transferase activity observed in certain leukemic cells.
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673
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Murthy GG, Peress NS, Khan SA. Demonstration of antibodies to testicular basement membrane by immunofluorescence in a patient with multiple primary endocrine deficiencies. J Clin Endocrinol Metab 1976; 42:637-41. [PMID: 770495 DOI: 10.1210/jcem-42-4-637] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Circulating antibodies directed against testicular basement membrane and germinal cells are demonstrated in a patient with multiple primary endocrine gland deficiencies involving the thyroid, adrenals, testes, and pernicious anemia. Testicular biopsy revealed focal destruction of seminiferous tubules and interstitial fibrosis. The tubular basement membranes showed sharply positive immunofluorescence when stained with the patient's FITC conjugated gamma globulins.
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674
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Khan SA, Bilquees F. The environment, attitudes and activities of rural women: a case study of a village in Punjab. PAKISTAN DEVELOPMENT REVIEW 1976; 15:237-71. [PMID: 12308180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/19/2023]
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675
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