PubMed Health⌕ Search

Biomedical subjects

A Azam

Publications and source records attributed to A Azam.

11 recordsLinked to original sources
PubMed2001

Synthesis, characterisation and antiamoebic activity of new thiophene-2-carboxaldehyde thiosemicarbazone derivatives and their cyclooctadiene Ru(II) complexes.

Reaction of new thiosemicarbazones (1-4) derived from thiophene-2-carboxaldehyde and cycloalkylaminothiocarbonylhydrazine with [Ru(eta(4)-C8H12)(CH3CN)2Cl2] leads to form complexes (1a-4a) of the type [Ru(eta(4)-C8H12)(TSC)Cl2] (where TSC=thiosemicarbazone). All the compounds have been characterised by elemental analysis, IR, 1H NMR, electronic spectra and thermogravimetric analysis. It is concluded that the thionic sulphur and the azomethine nitrogen atom of the ligands are bonded to the metal ion. In vitro antiamoebic screening against (HK-9) strain of Entamoeba histolytica indicated that the Ru(II) complexes of thiophene-2-carboxaldehyde thiosemicarbazones were found more active than the thiosemicarbazones.

Animals↗
PubMed2000

Synthesis and antiamoebic activity of new cyclooctadiene ruthenium(II) complexes with 2-acetylpyridine and benzimidazole derivatives.

Reaction of [Ru(eta4-C8H12) (CH3CN)2 Cl2] with 2-(2-pyridyl) benzimidazole or Schiff bases derived from 2-acetylpyridine and S-methyldithiocarbazate, S-benzyldithiocarbazate and thiosemicarbazide leads to form new complexes of the type [Ru(eta4-C8H12)(L)Cl2] (where L=ligand). In vitro, most of the compounds exhibited potent activity and the Ru derivatives 1a [Ru(eta4-C8H12)(2-Acpy-SMDT)Cl2], 2a [Ru(eta4-C8H12)(2-Acpy-SBDT)Cl2] and 3a [Ru(eta4-CsH12)(2-Acpy-TSC)Cl2] were found more active than metronidazole against (HK-9) strain of Entamoeba histolytica.

Amebicides↗
PubMed2000

Inter- and intra-strain variation in the 5.8S ribosomal RNA and internal transcribed spacer sequences of Entamoeba histolytica and comparison with Entamoeba dispar, Entamoeba moshkovskii and Entamoeba invadens.

The ribosomal RNA genes in Entamoeba histolytica are located on circular DNA molecules in about 200 copies per genome equivalent. Nucleotide sequence analysis of the 5.8S rRNA gene and the flanking internal transcribed spacers was carried out to determine the degree of sequence divergence in the multiple rRNA gene copies of a given strain; amongst three different E. histolytica strains (HM-1:IMSS, Rahman and HK-9); and amongst four species of Entamoeba (Entamoeba histolytica, Entamoeba dispar, Entamoeba moshkovskii and Entamoeba invadens). The results show that all rRNA gene copies of a given strain are identical. Few nucleotide positions varied between strains of a species but the differences were very pronounced amongst species. In general, the internal transcribed spacer 2 sequence was more variable and may be useful for strain- and species-identification. The 5.8S rRNA gene and the internal transcribed spacer 2 of E. invadens were unusually small in size.

Animals↗
PubMed1996

Identification of novel genes from Entamoeba histolytica by expressed sequence tag analysis.

Shotgun sequencing of cDNA clones is now an established approach to gain insight into the expressed nucleotide (nt) sequences in a given cell. We analysed 100 randomly picked cDNA clones of the protozoan parasite, Entamoeba histolytica, by nt sequencing, with a view to obtain novel gene sequences not detected so far by biochemical and genetic analyses. About 56% of the analysed clones showed significant homology with other genes in the database, including a number of genes whose presence may not be suspected in E. histolytica owing to its unusual subcellular organization. The results suggest that this approach can provide important clues to understand unique biochemical mechanisms in this parasite.

Animals↗
PubMed1994

Localization of endothelin-1 and its binding sites in scleroderma skin.

OBJECTIVE: Endothelin-1 (ET-1) has been implicated in the pathogenesis of systemic sclerosis (SSc) as it is both a potent vasoconstrictor and fibroblast mitogen and is raised in the circulation of patients with SSc and primary Raynaud's phenomenon. METHODS: We examined the localization and level of expression of ET-1 and its putative receptors in clinically "uninvolved" (i.e., prescleroderma skin) and involved skin from patients with diffuse cutaneous systemic sclerosis (dcSSc), using the alkaline phosphatase antialkaline phosphatase technique while ET-1 binding sites were examined using in vitro autoradiography. RESULTS: There was an increase in dermal ET-1 staining in clinically uninvolved and involved skin from patients with early active dcSSc compared with late stage fibrotic SSc skin and normal skin from healthy volunteers. Increased ET-1 staining was associated predominantly with the superficial vessels in the SSc skin sections. In addition, there was a significant increase in [125I]ET-1 binding to superficial vessels and the dermal/epidermal junction in SSc skin compared with the binding to similar structures in normal tissue. There was no change in [125I]ET-1 binding to the deep dermal vessels in both SSc and normal skin. This increase in [125I]ET-1 binding in SSc skin was not maintained with increasing tissue fibrosis. CONCLUSION: The presence of increased ET-1 levels as well as its binding sites in both the prescleroderma and involved skin of patients with dcSSc compared to controls suggests that ET-1 may play a role in the pathology of dermal fibrosis and vasoconstriction in SSc.

Adult↗