Association of Triglyceride and C-reactive Protein Level with Severity of Angiographically Defined Coronary Artery Disease.

Coronary artery disease (CAD) is considered as a major cause of morbidity and mortality worldwide. Inflammatory cytokines play an important role in the pathogenesis and progression of atherosclerosis. The aim of the study was to find out the association of C-reactive protein (CRP) and triglyceride (TG) level on the severity of CAD in patients with ischemic heart disease (IHD). This cross-sectional study was performed in the Department of Cardiology, National Institute of Cardiovascular Diseases, Dhaka, Bangladesh during the period of March 2018 to February 2021. Total 431 patients with ischemic heart disease were enrolled after taking informed written consent. CRP values were categorized into normal (<6 mg/L), borderline (6-10 mg/L) and high (>10mg/L) and TG level were categorized into normal (<150 mg/dl), borderline (150-199mg/dl) and high (≥200 mg/dl). Patients with ischemic heart disease (IHD) were stratified according to CRP value and TG level. Severity of CAD was assessed by the Gensini score. Most of the patients (33.4%) belonged to age 51-60 years. The mean age was 51.31±10.30 years. The majority (74.5%) of patients were male. Among risk factors, the highest 205(47.6%) patients were smokers followed by hypertension 190(44.1%) and diabetes mellitus 175(40.5%). The association of TG and CRP with the whole spectrum of IHD was found statistically significant (p<0.05). Severe CAD was found higher in high TG and high CRP level group compared with the other groups and was statistically significant. Inflammation assessed by high CRP and hypertriglyceridemia associated with the risk and severity of CAD.

An Echocardiographic Study of the Right Ventricular Diastolic Function in Systemic Hypertension and Its Relation with the Left Ventricular Homologous Changes.

Diastolic dysfunction is a major predictor of mortality and morbidity in hypertensive patients. Not only LV, the RV is also expected to be affected in this overall procedure. To observe the Echocardiographic changes of diastolic function of the RV in systemic HTN and their relation with similar parameters of the LV was the objective. TDI was used in association with standard Doppler modality. In this cross-sectional study, 50 hypertensive subjects were studied who were devoid of any other conditions that may influence the diastolic function of the RV from 01 May 2012 to 31 October 2012 at Bangabandhu Sheikh Mujib Medical University (BSMMU), Dhaka, Bangladesh. In addition to 2D and M-mode evaluation, standard Doppler and pulsed tissue Doppler assessment of both ventricles were performed. Measurements were obtained for diastolic as well as systolic function of both ventricles. The RV diastolic parameters were impaired in both standard Doppler and tissue Doppler analysis in association with LV parameters. Systolic functions (LV FS and RV TAPSE) were preserved. Doppler-derived tricuspid peak E and E/A were related negatively to septal thickness, but tissue Doppler-derived RV Em/Am showed negative association with both RVAWT and septal thickness. RV RTm was related positively to RVAWT. The RV diastolic parameters showed positive relation with the LV similar parameters both in standard Doppler (E peak velocity, E/A ratio and EDT) and tissue Doppler (Em peak velocity, Em/Am and PCTm) assessment. So, in systemic HTN, LV diastolic dysfunction is also associated with diastolic disturbances of the RV. Pulsed tissue Doppler is a useful tool to detect the changes. RV diastolic parameters correlate well with those of the LV. Prolongation of the active relaxation (RTm) phase of RV is due to its increased wall thickness.

Pattern and Extent of Tricuspid Valve Involvement in Chronic Rheumatic Heart Disease.

Rheumatic heart disease causes a significant number of morbidity and mortality in Bangladesh. Although the mitral and the aortic valve are the two most involved valves in rheumatic heart disease, the tricuspid valve disease is not uncommon secondary to, or in association with, mitral or aortic valve disease, but receives less attention as compared to the primary left-sided valve disease. Appropriate treatment of the tricuspid valve disease may improve long-term functional outcome. But the pattern and extent of the tricuspid valve involvement was not studied recently. This study was carried out to observe the pattern and extent of tricuspid valve involvement in Rheumatic Heart Disease patients. This observational analytical study was undertaken in the department of Cardiology, Bangabandhu Sheikh Mujib Medical University, Dhaka, Bangladesh from December 2010 to September 2011. Considering all ethical issues, data were collected from 173 subjects who underwent Echocardiography for their Chronic Rheumatic heart disease. Pattern of tricuspid valve involvement was observed by using Transthoracic Echocardiography by 2D, M mode and Doppler assessment. One hundred seventy three (173) patients with Rheumatic Heart disease was studied, out of these, 36 patients had evidence of tricuspid valve involvement based on echocardiographic findings. Fifteen (15) patients had Tricuspid stenosis and 36 patients had Tricuspid Regurgitation in the patients with TV involvement. All the patients with TV involvement had thickened leaflets. Doming, restriction of motion and calcification were present in different proportions. From this study, it can be concluded that organic tricuspid valve involvement in RHD is not uncommon in our country.

A Case of Severe Coarctation of Aorta Associated With Bicuspid Aortic Valve Managed Surgically.

Coarctation of the aorta is a congenital cardiac malformation that can go undiagnosed until old age with only hypertension as a marker of its presence because clinical signs can be subtle and overlooked if a complete physical exam is not performed. Long-term survival is exceptional in patients with untreated aortic coarctation. In this case report, we present a late diagnosis of aortic coarctation in a 45-year-old male. Our patient was relatively asymptomatic until he presented with exertional dyspnea and fatigue in his fourth decade of life in Bangabandhu Sheikh Mujib Medical University (BSMMU), on the month of August, 2016. The patient was managed by surgery of aorta. After the 6 months follow-up visit, the patient was in good clinical condition.

Characterization of key residues in the subdomain encoded by exons 8 and 9 of human inducible nitric oxide synthase: a critical role for Asp-280 in substrate binding and subunit interactions.

Human inducible nitric oxide synthase (iNOS) is active as a dimer of two identical subunits. Each subunit has an amino-terminal oxygenase domain that binds the substrate l-Arg and the cofactors heme and tetrahydrobiopterin and a carboxyl-terminal reductase domain that binds FMN, FAD, and NADPH. We previously demonstrated that a subdomain in the oxygenase domain encoded by exons 8 and 9 is important for dimer formation and NO synthesis. Further, we identified Trp-260, Asn-261, Tyr-267, and Asp-280 as key residues in that subdomain. In this study, using an Escherichia coli expression system, we produced, purified, and characterized wild-type iNOS and iNOS-Ala mutants. Using H(2)O(2)-supported oxidation of N(omega)-hydroxy-l-Arg, we demonstrate that the iNOS mutants' inabilities to synthesize NO are due to selective defects in the oxygenase domain activity. Detailed characterization of the Asp-280-Ala mutant revealed that it retains a functional reductase domain, as measured by its ability to reduce cytochrome c. Gel permeation chromatography confirmed that the Asp-280-Ala mutant exists as a dimer, but, in contrast to wild-type iNOS, urea-generated monomers of the mutant fail to reassociate into dimers when incubated with l-Arg and tetrahydrobiopterin, suggesting inadequate subunit interaction. Spectral analysis reveals that the Asp-280-Ala mutant does not bind l-Arg. This indicates that, in addition to dimerization, proper subunit interaction is required for substrate binding. These data, by defining a critical role for Asp-280 in substrate binding and subunit interactions, give insights into the mechanisms of regulation of iNOS activity.

Novel kanamycin/neomycin phosphotransferase cassette increases transformation efficiency in E. coli.

Stable transformation depends on the efficient delivery of DNA into cells and the robust expression of genes that encode proteins which provide resistance to selective (cytotoxic) compounds. We have examined the possibility that altering the 5'untranslated region (UTR) of a selectable marker may increase transformation efficiency. A 15-nucleotide synthetic UTR (the so-called universal translational enhancer [UTE]) was placed upstream of a kanamycin/neomycin phosphotransferase (kanaR) gene to create a novel expression cassette, UTE-kanaR. In comparison to a wild-type version of kanaR, UTE-kanaR produced up to 30-fold more transformants in E. coli. The superior performance of UTE-kanaR was independent of the promoter strength, indicating that the gene may find general use in routine transformation experiments.

Roles of Gln81 and Cys80 in catalysis by glycosylphosphatidylinositol-phospholipase C from Trypanosoma brucei.

Glycosylphosphatidylinositol-specific phospholipase C (GPtdIns-PLC) is found in the protozoan parasite Trypanosoma brucei. A region of protein sequence similarity exists between the protozoan enzyme and eubacterial phosphatidylinositol-phospholipases C. The functional relevance of Cys80 and Gln81 of GPtdIns-PLC, both in this region, was tested with a panel of mutations at each position. Gln81Glu, Gln81Ala, Gln81Gly, Gln81Lys and Gln81Leu mutants were inactive. Cleavage of GPtdIns was detectable in Gln81Asn, although the specific activity decreased 500-fold, and kcat was reduced 50-fold. Thus an amide side-chain at residue 81 is essential for catalysis by GPtdIns-PLC. Sulfhydryl reagents inactivate GPtdIns-PLC, suggesting that a Cys could be close to the enzyme active site. Surprisingly, p-chloromercuriphenyl sulfonate (p-CMPS) is significantly more potent than N-ethylmaleimide, the less bulky compound. This knowledge prompted us to test whether replacement of Cys80 with an amino acid possessing a bulky side-chain would inactivate GPtdIns-PLC: Cys80Ala, Cys80Thr, Cys80Phe, Cys184Ala, and Cys269-270-273Ser were constructed for that purpose. Cys80Phe lacked enzyme activity, while Cys80Ala, Cys80Thr and Cys269-270-273Ser retained 33 to 100% of wild-type activity. Interestingly, the Cys80Ala and Cys80Thr mutants became resistant to p-CMPS, as predicted if the sulfhydryl reagent reacted with Cys80 in the wild-type enzyme to form a cysteinyl mercurylphenylsulfonate moiety, a bulky adduct that inactivated GPtdIns-PLC, similar to the Cys80Phe mutation. We conclude that a bulky side-chain (or adduct) at position 80 of GPtdIns-PLC abolishes enzyme activity. Together, these observations place Cys80 and Gln81 at, or close to, the active site of GPtdIns-PLC from T. brucei.

Effect of short 5' UTRs on protein synthesis in two biological kingdoms.

Efficient ribosomal protein synthesis is dependent on cis-acting elements in the 5' untranslated region (UTR) of mRNAs. Between prokaryotes and eukaryotes, the sequence and location of these elements differ to the extent of not being functionally interchangeable. We explored the possibility of constructing bifunctional UTRs that could direct translation in both prokaryotes and eukaryotes. A variant of a UTR from ner of phage Mu (ner-ACC) enhanced protein synthesis in a rabbit reticulocyte lysate, and it was compared to a lacZ-CTA, containing the lambda cro RBS and the Escherichia coli lacZ spacer. Several mutants in the -3 to -1 regions of both lacZ-CTA and ner-ACC were tested in rabbit reticulocyte lysate and E. coli to select UTRs that were optimized simultaneously for both biological kingdoms. The lacZ-ATC proved 217-fold more effective than ner-ACC in this cross-species ability to enhance translation. The lacZ-ACC and ner-ATC were 83- and 78-fold, respectively, better than ner-ACC. We conclude that short UTRs (12-15 nt in length) can be fine-tuned in the -9 to -1 regions to enhance protein synthesis concurrently in prokaryotes and eukaryotes. In related studies, we show that nt at the -3 to -1 region of mRNAs exert an enormous impact on synthesis of proteins in E. coli.

Anatomy of the stimulative sequences flanking the ARS consensus sequence of chromosome VI in Saccharomyces cerevisiae.

We have analyzed the relationship between autonomously replicating sequence (ARS) structure and function for three ARS (ARS605, ARS607 and ARS609) from chromosome VI of Saccharomyces cerevisiae by systematic XhoI-linker mutation in the ARS consensus sequence (ACS) and flanking sequences. All mutations that encroached upon the ACS destroyed ARS activity. DNA sequences stimulative for ARS function were identified on either side of the ACS of ARS605 and only on the 3'-side of the ACS of ARS607. In ARS609, however, no such stimulative sequences were observed. Base substitutions complementary to the wild-type sequence of those stimulative regions, in ARS605 and ARS607, that did not change the delta G of unwinding nor affected ARS activity suggests that these regions have, at least, a function as DNA-unwinding elements (DUE). ARS605, ARS607 and ARS609 DNA are of low delta G value and showed hypersensitivity to single-strand-specific nuclease when inserted in negatively supercoiled plasmid. Linker mutations inhibitory for ARS activity (5L11 and 7L14) also caused significant changes in local nucleotide (nt) sensitivity within the ACS and its adjoining regions. Complementary base substitutions, however, did not affect these changes in local nt sensitivity. These results imply that the stimulative regions flanking the ACS are necessary to produce an optimum conformation around the ACS which may be important for full ARS activity.

A protein which binds preferentially to single-stranded core sequence of autonomously replicating sequence is essential for respiratory function in mitochondrial of Saccharomyces cerevisiae.

From yeast nuclear extract, we have identified several DNA-protein complexes using the T-rich strand of core consensus sequence of autonomously replicating sequence by gel shift assay. One of them showed preferential binding to the T-rich sequence of the DNA. We have partially purified a protein constituent of this complex and cloned its gene. The gene has an open reading frame encoding a protein of 380 amino acids (M(r) = 42,100) which is processed to a mature protein of 371 amino acids (M(r) = 40,900). The protein has neither significant amino acid homology with any previously reported proteins nor characteristic motifs. A putative HAP2/HAP3/HAP4 binding sequence was found at about 1 kilobase upstream of the gene. Disruption of the chromosomal gene revealed that the gene was neither essential for cell viability nor involved in DNA replication, but was essential for mitochondrial respiratory function. We therefore named the gene MRF1 for mitochondrial respiratory function 1. In a mrf1 null mutant the absorption spectra of cytochromes b, a, and a3 were undetectable, although mitochondrial DNA and protein synthesis in mitochondria were intact. Antibodies against MRF1 detected the antigen localized predominantly in the nucleus in vivo. These results suggest that MRF1 is a transcriptional regulatory protein of some genes whose products are necessary for the functional assembly of mitochondrial respiratory proteins.

Location and characterization of autonomously replicating sequences from chromosome VI of Saccharomyces cerevisiae.

We have reported the isolation of linking clones of HindIII and EcoRI fragments, altogether spanning a 230-kb continuous stretch of chromosome VI. The presence or absence of autonomously replicating sequence (ARS) activities in all of these fragments has been determined by using ARS searching vectors containing CEN4. Nine ARS fragments were identified, and their positions were mapped on the chromosome. Structures essential for and/or stimulative to ARS activity were determined for the ARS fragments by deletions and mutations. The organization of functional elements composed of core and stimulative sequences was found to be variable. Single core sequences were identified in eight of nine ARSs. The remaining ARS (ARS603) essential element is composed of two core-like sequences. The lengths of 3'- and 5'-flanking stimulative sequences required for the full activity of ARSs varied from ARS to ARS. Five ARSs required more than 100 bp of the 3'-flanking sequence as stimulative sequences, while not more than 79 bp of the 3' sequence was required by the other three ARSs. In addition, five ARSs had stimulative sequences varying from 127 to 312 bp in the 5'-flanking region of the core sequence. In general, these stimulative activities were correlated with low local delta Gs of unwinding, suggesting that the low local delta G of an ARS is an important element for determining the efficiency of initiation of replication of ARS plasmids.