Abdulkader Rahmo - Academia.edu (original) (raw)

Papers by Abdulkader Rahmo

Research paper thumbnail of The catalytic mechanism of carboxypeptidase A and active site intersubsite cooperativity

Research paper thumbnail of Cutaneous Leishmaniasis in Syria

Cutaneous leishmaniasis (CL) is a public health problem in Syria call for this parasite’s epidemi... more Cutaneous leishmaniasis (CL) is a public health problem in Syria call for this parasite’s epidemiological and evolutionary investigation. Evaluation of its population structure by multilocus enzyme electrophoresis (MLEE), current gold standard for classification, has some drawbacks ,such as the lack of discriminatory power below species level, it is labour intensive and time-consuming. In this study , MLEE has been replaced by applying PCR-RFLP of the internal transcribed spacer 1 (ITS1) for identification of leishmania at species level, on 37 samples were obtained from patients with suspected CL referred to Damascus Dermatology Hospital, 19 of them from Damascus and 18 from Aleppo. Intraspecific variation could be detected by the use of 9 hypervariable microsatellite markers. Our results showed that all samples were L. tropica. 26 genotype were detected, of wich 20 were unique to individual strains and 6 were shared by more than sample. Results also showed that there was amoderate ...

Research paper thumbnail of Regulation of urea and citrulline synthesis under physiological conditions

Biochemical Journal, 1993

Information on the regulation of urea synthesis in vivo was obtained by examining the relationshi... more Information on the regulation of urea synthesis in vivo was obtained by examining the relationship between ureagenesis in vivo, citrulline synthesis in vitro, and two factors currently hypothesized to exert short-term regulation of this pathway: the liver mitochondrial content of N-acetylglutamate (NAG) and substrate availability. Rats meal-fed for 4 h every day (4-20 schedule) or for 8 h every other day (8-40 schedule) were used. (1) The citrulline-synthesizing capacity of mitochondria from livers of rats on the 8-40 schedule exceeded the corresponding velocity of urea synthesis in vivo at all time points studied. (2) Mitochondrial NAG in these livers increased from 127 +/- 32 pmol/mg of protein at 0 h to 486 +/- 205 pmol/mg at 3 h after the start of a meal, and decreased thereafter, but the correlation between NAG content and the velocity of citrulline synthesis was not simple, suggesting that NAG is not the only determinant of the state of activation of carbamoyl phosphate syntha...

Research paper thumbnail of The N -acetylglutamate content and N -acetylglutamate synthase activity of human liver

Biochemical Journal, 1991

Research paper thumbnail of Small mobile stem cells in emerging tissue organization

Journal of Cell Science and Therapy, Mar 29, 2016

Research paper thumbnail of In vivo and immunohistochemical study of dentin and pulp tissue regeneration in the root canal

The ultimate goal of endodontics therapy is the regeneration of tooth supporting tissues. This ca... more The ultimate goal of endodontics therapy is the regeneration of tooth supporting tissues. This case study evaluated whether the transplantation of autologous dental pulp stem cells with chitosan scaffold into pulpless root canals could mediate pulp regeneration in human mature teeth. The dental pulp stem cells isolated from the patient`s pulp tissue. The cells were then seeded onto a chitosan scaffold and then transported into the root canal of the patient. After eight weeks the tooth was extracted and prepared for histological and immunohistochemical examination in purpose to identify the nature of tissues formed in the canal space. After endodontic regeneration procedures, pulplike tissue characterized by the presence of odontoblast-like cells aligning dentin-like hard tissue was observed. This is the first clinical and histological evidence in the dental literature that shows that pulp and dentin like tissue can be generated in a human tooth using dental pulp stem cells.

Research paper thumbnail of Ffect of S Elected I Nsecticides on SF 9 I Nsect C Ell L Ine

The toxic effect of three insecticides: dimethoate (organophosphate insecticide), acetamiprid (ne... more The toxic effect of three insecticides: dimethoate (organophosphate insecticide), acetamiprid (neonicotinoid insecticide) and deltamethrin (pyrethroid insecticide) were evaluated in vitro on cultured Sf9 cell line. Cell growth inhibition was measured by the 3(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. Regression Analysis was used to estimate the 20% inhibition of cells growth (IC20). The IC20 values obtained for deltamethrin, acetamiprid and dimethoate were: 46.8, 61.6 and 68.9 μM, respectively. The proportion of phagocytic cells was positively correlated with the applied concentrations of the insecticides.

Research paper thumbnail of Pyrosequencing for rapid detection of tuberculosis resistance to Rifampicin and Isoniazid in Syrian and Lebanese clinical isolates

International Journal of Mycobacteriology, 2015

Background: Rapid and accurate techniques are always welcomed for the detection of resistant stra... more Background: Rapid and accurate techniques are always welcomed for the detection of resistant strains of Mycobacterium tuberculosis MTB. Objectives: The objective of this study is to evaluate the pyrosequencing technology for the detection of MTB resistance to Rifampicin (RIF) and Isoniazid (INH) in Syrian and Lebanese clinical strains; 66 strains resistant to INH, among them 56 resistant also to RIF, were tested. Methods: Four pyrosequencing assays were optimized and applied to the following loci: rpoBrpoB RIF resistance-determining region, katG, the promoter regions of inhA and ahpC-oxyR intergenic region. Results: The prevalence of mutations on codon 315 of the katG gene, inhA and ahpc-oxyR were 42.4%, 21.2% and 9.0%, respectively, which make an overall sensitivity of 72.6% for INH resistance. All RIF-resistant strains contained at least one non-synonymous codon change in the sequenced rpoB region (507-533) relative to the ATCC reference strain. The RIF drug resistance region (RRDR) sequencing identified 96 modified codons representing 34 different mutations. Conclusions: The high sensitivity and the short turnaround time combined with multilocus sequencing of several isolates in parallel make pyrosequencing an attractive method for drug resistance screening for MTB.

Research paper thumbnail of Introducing a Novel Human Stem Cell with Exceptional Characteristics: Small, Mobile Stem Cells (SMS)

Journal of Life Sciences and Technologies, 2013

Blood especially umbilical cord blood is a valuable source of adult stem cells. These cells are q... more Blood especially umbilical cord blood is a valuable source of adult stem cells. These cells are quite heterogeneous, and are far from being fully explored. We describe herein a novel cell population with extraordinary features. Long-term adherent cell culture was initiated and characterized microscopically. Cell movement was measured using suitable software. Flow cytometric measurements were used to characterize surface antigens. Standard differentiation media were applied and histochemical methods used to examine differentiation. Cultured cells isolated from umbilical cord blood were very small, strongly adherent, CD34+ cells. They proliferated for more than a year in standard media without spontaneous differentiation, senescence or apoptosis, and displayed resistance to some adverse conditions. These cells formed a complex extracellular matrix, and multi-cellular layers. They exhibited exceptional kinetic characteristics with detected speed of 1.5 µm/sec. They are responsive to common differentiation inductive media. Under these conditions, clear changes to cell structure, and cell complex assembly, is microscopically observed. This cell type is termed SMS (Small, Mobile, Stem cell). Based on these exceptional features, we are confident that SMS cells will contribute significantly to a new understanding and appreciation of human stem cells; ushering new venues for therapeutic and biotechnological applications.

Research paper thumbnail of The Cytotoxic Effect of Essential Oil of Syrian Citrus Limon Peel on Human Colorectal Carcinoma Cell Line (LIM1863)

Middle East Journal of Cancer, 2012

Background : Essential oils are the volatile fraction of aromatic and medicinal plants created af... more Background : Essential oils are the volatile fraction of aromatic and medicinal plants created after extraction by steam or water distillation. Species of the genus Citrus (Rutaceae) have been widely used in traditional medicine as volatile oils and are currently the subject of numerous research. Citrus essential oil consists of different terpens that have antitumor activities. This study determines the cytotoxic effect of the essential oils of Citrus limon L. peels on a colorectal cancer cell line (LIM1863). Methods :We harvested four samples from four locations in Syria. Essential oils were prepared by hydrodistillation and analyzed by Gas chromatography-mass spectrometry (GC-MS).Various concentrations ofessential oils (0.5-48 µg/ml) were added to cultured cells and incubated for 72 h. Cell viability was evaluated byMTT-based cytotoxicity assay. Results :We noted 18 components that represented 98.81% of the total oil content. The major components were: limonene (61.8%-73.8%), γ-te...

Research paper thumbnail of The N-acetylglutamate content and N-acetylglutamate synthase activity of human liver

Biochemical Journal, 1991

... Abdulkader RAHMO and Luisa RAIJMAN University of Southern California, School of Medicine, Dep... more ... Abdulkader RAHMO and Luisa RAIJMAN University of Southern California, School of Medicine, Department of Biochemistry, 2011 Zonal Avenue, Los Angeles, CA 90033, USA 1. Tuchman, M. & Holzknecht, RA (1990) Biochem. ...

Research paper thumbnail of The catalytic mechanism of carboxypeptidase A and active site intersubsite cooperativity

Research paper thumbnail of The Cytotoxic Effect of Essential Oil of Syrian Citrus limon Peel on Human Colorectal Carcinoma Cell Line (Lim1863)

Middle East Journal of Cancer, 2012

Abstract Background: Essential oils are the volatile fraction of aromatic and medicinal plants cr... more Abstract Background: Essential oils are the volatile fraction of aromatic and medicinal plants created after extraction by steam or water distillation. Species of the genus Citrus (Rutaceae) have been widely used in traditional medicine as volatile oils and are currently the subject of numerous research. Citrusessential oil consists of different terpens that have antitumor activities. This study determines the cytotoxic effect of the essential oils of Citrus limon L. peels on a colorectal cancer cell line (LIM1863). Methods: We harvested four samples ...

Research paper thumbnail of The Cytotoxic Effect of Essential Oils Citrus Aurantium Peels on Human Colorectal Carcinoma Cell Line (LIM1863)

Citrus essential oils (EOs) contain different terpens that have been shown to possess antitumor e... more Citrus essential oils (EOs) contain different terpens that have been shown to possess antitumor effects. We determined the cytotoxic effect of essential oils of Citrus aurantium L. subspamara peels on a colorectal cancer cell line (Lim1863). Three samples were harvested from three locations in Syria. EOs were extracted by hydrodistilation and analyzed by GC-MS. EOs content of Limonene was96-97.7 % while α-pinene and β-myrcenewere0.35-1% and 0.9-1.4% respectively. Various concentrations of EOs (0.25-48 µl/ml) were added to cultured cells and incubated for 72 h. Cell viability was evaluated using the MTT-based cytotoxicity assay. The obtained IC50 value range of C. aurantium Eos was 2.18-2.44 µl/ml. In conclosion, C. aurantium peels Eos obviously reduced the cell viability and it might have cytotoxic effect against colorectal cancer cell line.

Research paper thumbnail of Effect of Selected Insecticides on SF9 Insect Cell Line

The toxic effect of three insecticides: dimethoate (organophosphate insecticide), acetamiprid (ne... more The toxic effect of three insecticides: dimethoate (organophosphate insecticide), acetamiprid (neonicotinoid insecticide) and deltamethrin (pyrethroid insecticide) were evaluated in vitro on cultured Sf9 cell line. Cell growth inhibition was measured by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. Regression Analysis was used to estimate the 20% inhibition of cells growth (IC 20). The IC 20 values obtained for deltamethrin, acetamiprid and dimethoate were: 46.8, 61.6 and 68.9 µM, respectively. The proportion of phagocytic cells was positively correlated with the applied concentrations of the insecticides.

Research paper thumbnail of Contribution of katG, ahpC and inhA mutations to the detection of isoniazid-resistant Mycobacterium tuberculosis isolates from Lebanon and Syria

International Journal of Mycobacteriology, 2015

This article appeared in a journal published by Elsevier. The attached copy is furnished to the a... more This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues. Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. In most cases authors are permitted to post their version of the article (e.g. in Word or Tex form) to their personal website or institutional repository. Authors requiring further information regarding Elsevier's archiving and manuscript policies are encouraged to visit: http://www.elsevier.com/authorsrights Author's personal copy Contribution of katG, ahpC and inhA mutations to the detection of isoniazid-resistant Mycobacterium tuberculosis isolates from Lebanon and Syria

Research paper thumbnail of Mycobacterium tuberculosis spoligotypes circulating in the Syrian population: A retrospective study

International Journal of Mycobacteriology, 2013

Genotyping Mycobacterium tuberculosis in Lebanon on the national level may be beneficial for asse... more Genotyping Mycobacterium tuberculosis in Lebanon on the national level may be beneficial for assessing patients and monitoring the therapeutic response to DOTS. This study aimed to characterize the spoligotypes of clinical isolates of M. tuberculosis patients collected between April 2004 and October 2005 from all Lebanese provinces. Isolates (n = 60) were cultured and identified by their biochemical characteristics. DNA extracts of these samples were amplified by PCR and genotyped by spoligotyping. Thirteen (13) patterns of M. tuberculosis complex family strains were identified: 41.6% of the strains belonged to the T 1 family, 25.0% to LAM 9, 10.0% to Haarlem 3, 3.3% to each of CAS, LAM 8, BCG and Family 36 and 1.7% to each of Haarlem 1, LAM 10, S, M. africanum, X 1 and T 3 families. The noticeable absence of Beijing and East African Indian families was not consistent with the patterns reported in neighbouring countries. A more inclusive study of the Lebanese population is necessary to accurately identify most of the prevailing families in the country.

Research paper thumbnail of The In-Vitro Toxic Effect of The Glycoalkaloids for Some Solanum Species Against The LIM-1863 Cell Line

Pharmacognosy Journal, 2014

Background The LIM-1863 Cell Line is one of the colon cancer types considered to be responsible f... more Background The LIM-1863 Cell Line is one of the colon cancer types considered to be responsible for a high rate of deaths, and the glycoalkaloids being natural substances existing in the Solanum species have anticancer effects. Objective This research aims at studying the effect of the glycoalkaloids on viability of the LIM-1863 cancerous cells in-vitro. Materials and Methods The glycoalkaloids in this study are extracted by the ultrasonic waves technique and detecting them by the Thin Layer Chromatography (TLC) in addition to incubating of the LIM-1863 cells with different concentrations of the glycoalkaloids for 48 hours and then assessing of the cell viability using the MTT assay.Results The findings showed that the glycoalkaloids have a toxic effect on the LIM-1863 cells and that half of the inhibiting concentration (IC 50) of the Solanum fruits extract: (Solanum nigrum L.), (Solanum villosum Mill.) and (Solanum elaeagnifolium Cav.) on the LIM-1863 cells have the (164.7, 35.91 and 12.14 µg/ml) values successively. Conclusion The observations indicated that the glycoalkaloids are able to inhibit the colon cancer cell proliferation.

Research paper thumbnail of Testing for the presence of Mycobacterium tuberculosis Beijing genotype strains in Syrian samples

International Journal of Mycobacteriology, 2012

The Beijing family of Mycobacterium tuberculosis (MTB) has been reported to have an exceptional c... more The Beijing family of Mycobacterium tuberculosis (MTB) has been reported to have an exceptional capacity to spread tuberculosis (TB) and induce multi-drug resistance. A method has been developed to distinguish this family from the rest of the MTB families through realtime DNA amplification and subsequent analysis of the melting point of an amplicon. Two pools of multi-drug resistant (MDR) MTB samples collected at two different time periods from various regions in Syria have been selected. This preliminary screening indicated a complete absence of the Beijing family in all samples. This research presents an effective differentiation of bacterial Beijing strains, with minimal effort and cost through analysis of differential amplicon melting points.

Research paper thumbnail of Genotypic detection of rifampicin-resistant M. tuberculosis strains in Syrian and Lebanese patients

Journal of Infection and Public Health, 2012

Setting: The incidence of multi-and extensively drug-resistant TB cases is increasing in many cou... more Setting: The incidence of multi-and extensively drug-resistant TB cases is increasing in many countries. Resistance to rifampicin is widely considered a surrogate marker for multiple drug resistant TB. No efforts have been made to identify and quantify the drug-resistant genotypes in the Syrian and Lebanese communities. Objective: The genotypic characterization of rpo B mutations in the rifampicin drugresistance region (RRDR) of resistant Mycobacterium tuberculosis isolates in Syrian and Lebanese patients. Design: The pyrosequencing technique was applied to DNA derived from the M. tuberculosis isolates of 56 patients. Results: RRDR sequencing identified 97 modified codons representing 35 different mutations; 31 (34%) of the 97 modifications were novel and have not been previously reported. The changes were mostly within codons 531 (37/97: 38%), 533 (28/97: 29%) and 526 (9/97: 9%). Additionally, 30 (54%) isolates had multiple codon changes. Conclusion: This study indicates the importance of the RRDR hotspot region for the detection of rifampicin resistance in MTB clinical isolates from Syrian and Lebanese patients. However, new mutations and mutations in other locations within the RRDR were also observed. The vast majority (95%) of the studied isolates from this pool of patients contained mutations in codons 531 and/or 533.

Research paper thumbnail of The catalytic mechanism of carboxypeptidase A and active site intersubsite cooperativity

Research paper thumbnail of Cutaneous Leishmaniasis in Syria

Cutaneous leishmaniasis (CL) is a public health problem in Syria call for this parasite’s epidemi... more Cutaneous leishmaniasis (CL) is a public health problem in Syria call for this parasite’s epidemiological and evolutionary investigation. Evaluation of its population structure by multilocus enzyme electrophoresis (MLEE), current gold standard for classification, has some drawbacks ,such as the lack of discriminatory power below species level, it is labour intensive and time-consuming. In this study , MLEE has been replaced by applying PCR-RFLP of the internal transcribed spacer 1 (ITS1) for identification of leishmania at species level, on 37 samples were obtained from patients with suspected CL referred to Damascus Dermatology Hospital, 19 of them from Damascus and 18 from Aleppo. Intraspecific variation could be detected by the use of 9 hypervariable microsatellite markers. Our results showed that all samples were L. tropica. 26 genotype were detected, of wich 20 were unique to individual strains and 6 were shared by more than sample. Results also showed that there was amoderate ...

Research paper thumbnail of Regulation of urea and citrulline synthesis under physiological conditions

Biochemical Journal, 1993

Information on the regulation of urea synthesis in vivo was obtained by examining the relationshi... more Information on the regulation of urea synthesis in vivo was obtained by examining the relationship between ureagenesis in vivo, citrulline synthesis in vitro, and two factors currently hypothesized to exert short-term regulation of this pathway: the liver mitochondrial content of N-acetylglutamate (NAG) and substrate availability. Rats meal-fed for 4 h every day (4-20 schedule) or for 8 h every other day (8-40 schedule) were used. (1) The citrulline-synthesizing capacity of mitochondria from livers of rats on the 8-40 schedule exceeded the corresponding velocity of urea synthesis in vivo at all time points studied. (2) Mitochondrial NAG in these livers increased from 127 +/- 32 pmol/mg of protein at 0 h to 486 +/- 205 pmol/mg at 3 h after the start of a meal, and decreased thereafter, but the correlation between NAG content and the velocity of citrulline synthesis was not simple, suggesting that NAG is not the only determinant of the state of activation of carbamoyl phosphate syntha...

Research paper thumbnail of The N -acetylglutamate content and N -acetylglutamate synthase activity of human liver

Biochemical Journal, 1991

Research paper thumbnail of Small mobile stem cells in emerging tissue organization

Journal of Cell Science and Therapy, Mar 29, 2016

Research paper thumbnail of In vivo and immunohistochemical study of dentin and pulp tissue regeneration in the root canal

The ultimate goal of endodontics therapy is the regeneration of tooth supporting tissues. This ca... more The ultimate goal of endodontics therapy is the regeneration of tooth supporting tissues. This case study evaluated whether the transplantation of autologous dental pulp stem cells with chitosan scaffold into pulpless root canals could mediate pulp regeneration in human mature teeth. The dental pulp stem cells isolated from the patient`s pulp tissue. The cells were then seeded onto a chitosan scaffold and then transported into the root canal of the patient. After eight weeks the tooth was extracted and prepared for histological and immunohistochemical examination in purpose to identify the nature of tissues formed in the canal space. After endodontic regeneration procedures, pulplike tissue characterized by the presence of odontoblast-like cells aligning dentin-like hard tissue was observed. This is the first clinical and histological evidence in the dental literature that shows that pulp and dentin like tissue can be generated in a human tooth using dental pulp stem cells.

Research paper thumbnail of Ffect of S Elected I Nsecticides on SF 9 I Nsect C Ell L Ine

The toxic effect of three insecticides: dimethoate (organophosphate insecticide), acetamiprid (ne... more The toxic effect of three insecticides: dimethoate (organophosphate insecticide), acetamiprid (neonicotinoid insecticide) and deltamethrin (pyrethroid insecticide) were evaluated in vitro on cultured Sf9 cell line. Cell growth inhibition was measured by the 3(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. Regression Analysis was used to estimate the 20% inhibition of cells growth (IC20). The IC20 values obtained for deltamethrin, acetamiprid and dimethoate were: 46.8, 61.6 and 68.9 μM, respectively. The proportion of phagocytic cells was positively correlated with the applied concentrations of the insecticides.

Research paper thumbnail of Pyrosequencing for rapid detection of tuberculosis resistance to Rifampicin and Isoniazid in Syrian and Lebanese clinical isolates

International Journal of Mycobacteriology, 2015

Background: Rapid and accurate techniques are always welcomed for the detection of resistant stra... more Background: Rapid and accurate techniques are always welcomed for the detection of resistant strains of Mycobacterium tuberculosis MTB. Objectives: The objective of this study is to evaluate the pyrosequencing technology for the detection of MTB resistance to Rifampicin (RIF) and Isoniazid (INH) in Syrian and Lebanese clinical strains; 66 strains resistant to INH, among them 56 resistant also to RIF, were tested. Methods: Four pyrosequencing assays were optimized and applied to the following loci: rpoBrpoB RIF resistance-determining region, katG, the promoter regions of inhA and ahpC-oxyR intergenic region. Results: The prevalence of mutations on codon 315 of the katG gene, inhA and ahpc-oxyR were 42.4%, 21.2% and 9.0%, respectively, which make an overall sensitivity of 72.6% for INH resistance. All RIF-resistant strains contained at least one non-synonymous codon change in the sequenced rpoB region (507-533) relative to the ATCC reference strain. The RIF drug resistance region (RRDR) sequencing identified 96 modified codons representing 34 different mutations. Conclusions: The high sensitivity and the short turnaround time combined with multilocus sequencing of several isolates in parallel make pyrosequencing an attractive method for drug resistance screening for MTB.

Research paper thumbnail of Introducing a Novel Human Stem Cell with Exceptional Characteristics: Small, Mobile Stem Cells (SMS)

Journal of Life Sciences and Technologies, 2013

Blood especially umbilical cord blood is a valuable source of adult stem cells. These cells are q... more Blood especially umbilical cord blood is a valuable source of adult stem cells. These cells are quite heterogeneous, and are far from being fully explored. We describe herein a novel cell population with extraordinary features. Long-term adherent cell culture was initiated and characterized microscopically. Cell movement was measured using suitable software. Flow cytometric measurements were used to characterize surface antigens. Standard differentiation media were applied and histochemical methods used to examine differentiation. Cultured cells isolated from umbilical cord blood were very small, strongly adherent, CD34+ cells. They proliferated for more than a year in standard media without spontaneous differentiation, senescence or apoptosis, and displayed resistance to some adverse conditions. These cells formed a complex extracellular matrix, and multi-cellular layers. They exhibited exceptional kinetic characteristics with detected speed of 1.5 µm/sec. They are responsive to common differentiation inductive media. Under these conditions, clear changes to cell structure, and cell complex assembly, is microscopically observed. This cell type is termed SMS (Small, Mobile, Stem cell). Based on these exceptional features, we are confident that SMS cells will contribute significantly to a new understanding and appreciation of human stem cells; ushering new venues for therapeutic and biotechnological applications.

Research paper thumbnail of The Cytotoxic Effect of Essential Oil of Syrian Citrus Limon Peel on Human Colorectal Carcinoma Cell Line (LIM1863)

Middle East Journal of Cancer, 2012

Background : Essential oils are the volatile fraction of aromatic and medicinal plants created af... more Background : Essential oils are the volatile fraction of aromatic and medicinal plants created after extraction by steam or water distillation. Species of the genus Citrus (Rutaceae) have been widely used in traditional medicine as volatile oils and are currently the subject of numerous research. Citrus essential oil consists of different terpens that have antitumor activities. This study determines the cytotoxic effect of the essential oils of Citrus limon L. peels on a colorectal cancer cell line (LIM1863). Methods :We harvested four samples from four locations in Syria. Essential oils were prepared by hydrodistillation and analyzed by Gas chromatography-mass spectrometry (GC-MS).Various concentrations ofessential oils (0.5-48 µg/ml) were added to cultured cells and incubated for 72 h. Cell viability was evaluated byMTT-based cytotoxicity assay. Results :We noted 18 components that represented 98.81% of the total oil content. The major components were: limonene (61.8%-73.8%), γ-te...

Research paper thumbnail of The N-acetylglutamate content and N-acetylglutamate synthase activity of human liver

Biochemical Journal, 1991

... Abdulkader RAHMO and Luisa RAIJMAN University of Southern California, School of Medicine, Dep... more ... Abdulkader RAHMO and Luisa RAIJMAN University of Southern California, School of Medicine, Department of Biochemistry, 2011 Zonal Avenue, Los Angeles, CA 90033, USA 1. Tuchman, M. & Holzknecht, RA (1990) Biochem. ...

Research paper thumbnail of The catalytic mechanism of carboxypeptidase A and active site intersubsite cooperativity

Research paper thumbnail of The Cytotoxic Effect of Essential Oil of Syrian Citrus limon Peel on Human Colorectal Carcinoma Cell Line (Lim1863)

Middle East Journal of Cancer, 2012

Abstract Background: Essential oils are the volatile fraction of aromatic and medicinal plants cr... more Abstract Background: Essential oils are the volatile fraction of aromatic and medicinal plants created after extraction by steam or water distillation. Species of the genus Citrus (Rutaceae) have been widely used in traditional medicine as volatile oils and are currently the subject of numerous research. Citrusessential oil consists of different terpens that have antitumor activities. This study determines the cytotoxic effect of the essential oils of Citrus limon L. peels on a colorectal cancer cell line (LIM1863). Methods: We harvested four samples ...

Research paper thumbnail of The Cytotoxic Effect of Essential Oils Citrus Aurantium Peels on Human Colorectal Carcinoma Cell Line (LIM1863)

Citrus essential oils (EOs) contain different terpens that have been shown to possess antitumor e... more Citrus essential oils (EOs) contain different terpens that have been shown to possess antitumor effects. We determined the cytotoxic effect of essential oils of Citrus aurantium L. subspamara peels on a colorectal cancer cell line (Lim1863). Three samples were harvested from three locations in Syria. EOs were extracted by hydrodistilation and analyzed by GC-MS. EOs content of Limonene was96-97.7 % while α-pinene and β-myrcenewere0.35-1% and 0.9-1.4% respectively. Various concentrations of EOs (0.25-48 µl/ml) were added to cultured cells and incubated for 72 h. Cell viability was evaluated using the MTT-based cytotoxicity assay. The obtained IC50 value range of C. aurantium Eos was 2.18-2.44 µl/ml. In conclosion, C. aurantium peels Eos obviously reduced the cell viability and it might have cytotoxic effect against colorectal cancer cell line.

Research paper thumbnail of Effect of Selected Insecticides on SF9 Insect Cell Line

The toxic effect of three insecticides: dimethoate (organophosphate insecticide), acetamiprid (ne... more The toxic effect of three insecticides: dimethoate (organophosphate insecticide), acetamiprid (neonicotinoid insecticide) and deltamethrin (pyrethroid insecticide) were evaluated in vitro on cultured Sf9 cell line. Cell growth inhibition was measured by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. Regression Analysis was used to estimate the 20% inhibition of cells growth (IC 20). The IC 20 values obtained for deltamethrin, acetamiprid and dimethoate were: 46.8, 61.6 and 68.9 µM, respectively. The proportion of phagocytic cells was positively correlated with the applied concentrations of the insecticides.

Research paper thumbnail of Contribution of katG, ahpC and inhA mutations to the detection of isoniazid-resistant Mycobacterium tuberculosis isolates from Lebanon and Syria

International Journal of Mycobacteriology, 2015

This article appeared in a journal published by Elsevier. The attached copy is furnished to the a... more This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues. Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. In most cases authors are permitted to post their version of the article (e.g. in Word or Tex form) to their personal website or institutional repository. Authors requiring further information regarding Elsevier's archiving and manuscript policies are encouraged to visit: http://www.elsevier.com/authorsrights Author's personal copy Contribution of katG, ahpC and inhA mutations to the detection of isoniazid-resistant Mycobacterium tuberculosis isolates from Lebanon and Syria

Research paper thumbnail of Mycobacterium tuberculosis spoligotypes circulating in the Syrian population: A retrospective study

International Journal of Mycobacteriology, 2013

Genotyping Mycobacterium tuberculosis in Lebanon on the national level may be beneficial for asse... more Genotyping Mycobacterium tuberculosis in Lebanon on the national level may be beneficial for assessing patients and monitoring the therapeutic response to DOTS. This study aimed to characterize the spoligotypes of clinical isolates of M. tuberculosis patients collected between April 2004 and October 2005 from all Lebanese provinces. Isolates (n = 60) were cultured and identified by their biochemical characteristics. DNA extracts of these samples were amplified by PCR and genotyped by spoligotyping. Thirteen (13) patterns of M. tuberculosis complex family strains were identified: 41.6% of the strains belonged to the T 1 family, 25.0% to LAM 9, 10.0% to Haarlem 3, 3.3% to each of CAS, LAM 8, BCG and Family 36 and 1.7% to each of Haarlem 1, LAM 10, S, M. africanum, X 1 and T 3 families. The noticeable absence of Beijing and East African Indian families was not consistent with the patterns reported in neighbouring countries. A more inclusive study of the Lebanese population is necessary to accurately identify most of the prevailing families in the country.

Research paper thumbnail of The In-Vitro Toxic Effect of The Glycoalkaloids for Some Solanum Species Against The LIM-1863 Cell Line

Pharmacognosy Journal, 2014

Background The LIM-1863 Cell Line is one of the colon cancer types considered to be responsible f... more Background The LIM-1863 Cell Line is one of the colon cancer types considered to be responsible for a high rate of deaths, and the glycoalkaloids being natural substances existing in the Solanum species have anticancer effects. Objective This research aims at studying the effect of the glycoalkaloids on viability of the LIM-1863 cancerous cells in-vitro. Materials and Methods The glycoalkaloids in this study are extracted by the ultrasonic waves technique and detecting them by the Thin Layer Chromatography (TLC) in addition to incubating of the LIM-1863 cells with different concentrations of the glycoalkaloids for 48 hours and then assessing of the cell viability using the MTT assay.Results The findings showed that the glycoalkaloids have a toxic effect on the LIM-1863 cells and that half of the inhibiting concentration (IC 50) of the Solanum fruits extract: (Solanum nigrum L.), (Solanum villosum Mill.) and (Solanum elaeagnifolium Cav.) on the LIM-1863 cells have the (164.7, 35.91 and 12.14 µg/ml) values successively. Conclusion The observations indicated that the glycoalkaloids are able to inhibit the colon cancer cell proliferation.

Research paper thumbnail of Testing for the presence of Mycobacterium tuberculosis Beijing genotype strains in Syrian samples

International Journal of Mycobacteriology, 2012

The Beijing family of Mycobacterium tuberculosis (MTB) has been reported to have an exceptional c... more The Beijing family of Mycobacterium tuberculosis (MTB) has been reported to have an exceptional capacity to spread tuberculosis (TB) and induce multi-drug resistance. A method has been developed to distinguish this family from the rest of the MTB families through realtime DNA amplification and subsequent analysis of the melting point of an amplicon. Two pools of multi-drug resistant (MDR) MTB samples collected at two different time periods from various regions in Syria have been selected. This preliminary screening indicated a complete absence of the Beijing family in all samples. This research presents an effective differentiation of bacterial Beijing strains, with minimal effort and cost through analysis of differential amplicon melting points.

Research paper thumbnail of Genotypic detection of rifampicin-resistant M. tuberculosis strains in Syrian and Lebanese patients

Journal of Infection and Public Health, 2012

Setting: The incidence of multi-and extensively drug-resistant TB cases is increasing in many cou... more Setting: The incidence of multi-and extensively drug-resistant TB cases is increasing in many countries. Resistance to rifampicin is widely considered a surrogate marker for multiple drug resistant TB. No efforts have been made to identify and quantify the drug-resistant genotypes in the Syrian and Lebanese communities. Objective: The genotypic characterization of rpo B mutations in the rifampicin drugresistance region (RRDR) of resistant Mycobacterium tuberculosis isolates in Syrian and Lebanese patients. Design: The pyrosequencing technique was applied to DNA derived from the M. tuberculosis isolates of 56 patients. Results: RRDR sequencing identified 97 modified codons representing 35 different mutations; 31 (34%) of the 97 modifications were novel and have not been previously reported. The changes were mostly within codons 531 (37/97: 38%), 533 (28/97: 29%) and 526 (9/97: 9%). Additionally, 30 (54%) isolates had multiple codon changes. Conclusion: This study indicates the importance of the RRDR hotspot region for the detection of rifampicin resistance in MTB clinical isolates from Syrian and Lebanese patients. However, new mutations and mutations in other locations within the RRDR were also observed. The vast majority (95%) of the studied isolates from this pool of patients contained mutations in codons 531 and/or 533.