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Biomedical subjects

M Khalili

Publications and source records attributed to M Khalili.

16 recordsLinked to original sources
PubMed2006

Development and evaluation of a one-step real-time reverse transcription polymerase chain reaction assay for the detection of salmonid alphaviruses in serum and tissues.

We designed 4 primer pairs to amplify conserved regions of the E1 or nsP4 genes of salmonid alphavirus (SAV) and evaluated their performance in optimized 1-step SYBR green real-time RT-PCR (RRT-PCR) assays. A single primer pair, amplifying a 227 bp segment of E1 was then chosen for further study. This RRT-PCR was shown to be highly repeatable and reproducible over a wide range of RNA dilutions, with a linear relationship between cycle threshold (Ct) value and RNA concentration over a 10(7) dilution range. The limit of detection was calculated to be < or = 1.5 TCID50 ml(-1). When applied to sera previously screened by virus isolation for SAV viraemia, the RRT-PCR correctly identified all 13 culture-positive samples, as well as finding an additional 28 sera positive. Relative semi-quantitation of sera showed a very highly significant relationship between copy number and TCID50 (p < 0.001, R2 = 0.9563). Following experimental infection of salmon, heart samples were consistently positive until 21 d post infection (dpi), with (weak) positive signals still detectable in 50% of fish 70 dpi.

Alphavirus↗
PubMed2006

A novel single step double positive double negative selection strategy for beta-globin gene replacement.

beta-Thalassemias are a heterogeneous group of autosomal recessive disorders, characterized by reduced or absence of the beta-globin chain production by the affected alleles. Transplantation of genetically corrected autologous hematopoietic stem cell (HSC) is an attractive approach for treatment of these disorders. Gene targeting (homologous recombination) has many desirable features for gene therapy due to its ability to target the mutant genes and restore their normal expression. In the present study, a specific gene construct for beta-globin gene replacement was constructed consisting of: two homologous stems including, upstream and downstream regions of beta-globin gene, beta-globin gene lying between hygromycin and neomycin resistant genes as positive selection markers and thymidine kinase expression cassettes at both termini as negative selection marker. All segments were subcloned into pBGGT vector. The final plasmid was checked by sequencing and named as pFBGGT. Mammalian cell line COS-7 was transfected with linear plasmid by lipofection followed by positive and negative selection. DNA of the selected cells was analyzed by PCR and sequencing to confirm the occurrence of homologous recombination. In this novel strategy gene replacement was achieved in one step and by a single construct.

Animals↗
PubMed2005

Physics-based protein-structure prediction using a hierarchical protocol based on the UNRES force field: assessment in two blind tests.

Recent improvements in the protein-structure prediction method developed in our laboratory, based on the thermodynamic hypothesis, are described. The conformational space is searched extensively at the united-residue level by using our physics-based UNRES energy function and the conformational space annealing method of global optimization. The lowest-energy coarse-grained structures are then converted to an all-atom representation and energy-minimized with the ECEPP/3 force field. The procedure was assessed in two recent blind tests of protein-structure prediction. During the first blind test, we predicted large fragments of alpha and alpha+beta proteins [60-70 residues with C(alpha) rms deviation (rmsd) <6 A]. However, for alpha+beta proteins, significant topological errors occurred despite low rmsd values. In the second exercise, we predicted whole structures of five proteins (two alpha and three alpha+beta, with sizes of 53-235 residues) with remarkably good accuracy. In particular, for the genomic target TM0487 (a 102-residue alpha+beta protein from Thermotoga maritima), we predicted the complete, topologically correct structure with 7.3-A C(alpha) rmsd. So far this protein is the largest alpha+beta protein predicted based solely on the amino acid sequence and a physics-based potential-energy function and search procedure. For target T0198, a phosphate transport system regulator PhoU from T. maritima (a 235-residue mainly alpha-helical protein), we predicted the topology of the whole six-helix bundle correctly within 8 A rmsd, except the 32 C-terminal residues, most of which form a beta-hairpin. These and other examples described in this work demonstrate significant progress in physics-based protein-structure prediction.

Amino Acid Sequence↗
PubMed2001

Caffeine increases paragigantocellularis neuronal firing rate and induces withdrawal signs in morphine-dependent rats.

Using single unit recording in nucleus paragigantocellularis neurons located in the rostral ventrolateral medulla, and measuring the precipitated withdrawal syndrome, we investigated whether chronic morphine administration would produce adaptive changes in the adenosine system. Caffeine (50 mg/kg, i.p.) induced withdrawal signs (head shakes, tooth chattering, ejaculation, chewing, and irritability) in morphine-dependent rats 10-18 min after the injection. Only the tooth chattering and diarrhea were expressed following a direct paragigantocellularis injection of caffeine (200 microM, 0.5 microl). The spontaneous activity of paragigantocellularis neurons was significantly decreased by microinjection of both adenosine (10 nM) and an adenosine A1 receptor-selective agonist, cyclohexyladenosine (200 microM), into the paragigantocellularis nucleus of both control and morphine-dependent rats, but the decrease in firing rate of paragigantocellularis neurons of morphine-dependent rats was greater than that of control ones. There was also a significant enhancement of spontaneous activity of paragigantocellularis neurons 8-15 min after caffeine administration (50 mg/kg, i.p.) and 10-18 min after the injection of an adenosine A1 receptor-selective antagonist 8-phenyltheophylline (10 mg/kg, i.p.) in both control and morphine-dependent rats. However, the effect of the antagonists was greater in morphine-dependent rats than in control ones. These data suggest that there is an increase in the sensitivity of nucleus paragigantocellularis neurons to adenosine receptor ligands in morphine-dependent rats that may be associated with the ability of caffeine to produce withdrawal signs.

Adenosine↗
PubMed2000

Interferon and ribavirin versus interferon and amantadine in interferon nonresponders with chronic hepatitis C.

OBJECTIVE: The aim of this study was to compare the potential efficacy and safety of a combination of interferon and ribavirin with that of interferon and amantadine in patients who had previously failed to respond to interferon monotherapy. METHODS: A total of 29 patients were randomized to 3 million units of alpha-interferon three times weekly with 1000 mg of ribavirin daily (group A, n = 14) or an identical dose of alpha-interferon and amantadine hydrochloride given in a dose of 200 mg daily (group B, n = 15). Patients were treated for 24 wk and observed for 24 wk posttreatment. RESULTS: The treatment groups were evenly matched with respect to gender, frequency of genotype 1, presence of fibrosis, as well as baseline alanine aminotransferase (ALT) and HCV RNA levels. At the end of therapy, five of 14 or 36% of patients in group A versus 0 of 15 in group B had both normal serum ALT and nondetectable HCV RNA by polymerase chain reaction (p = 0.017). A complete response was sustained, however, in only two of 13 patients (15%) in group A who completed 24 wk of observation posttreatment. CONCLUSIONS: A substantial proportion of interferon nonresponders have an end-of-treatment biochemical and virological response to a combination of interferon and ribavirin, and sustained responses are possible. The addition of amantadine to interferon, in contrast, does not seem to enhance the antiviral effectiveness of interferon in patients who have previously failed to respond.

Adult↗
PubMed2000

Photosensitization of red blood cell hemolysis by lutetium texaphyrin.

Lutetium (III) texaphyrin photosensitizes postirradiation or "delayed" photohemolysis (DPH) of human and bovine red blood cells at 730 nm by a Type-2 pathway mediated by singlet molecular oxygen. The DPH rate increases with increasing incubation temperature and with the second power of the incident fluence. The experimental DPH curves are in good agreement with a multi-hit kinetics model based on target theory.

Animals↗
PubMed1993

A survey of mineral status of soils, feeds and cattle in the Selale Ethiopian highlands. I. Macro elements.

The macro mineral status of cattle in the Selale highlands of Ethiopia was evaluated during the rainy and dry seasons of 1989 and 1990 in terms of mineral concentrations in soils, feeds, blood plasma and faeces on 25 farms. Bone samples from animals of local breeds from a slaughter house were collected during the rainy and dry seasons of 1990. Soils were analysed for pH, organic matter, Ca, P, Mg, Na and K. The results indicated wide variation in the concentrations of minerals on different farms. Available feeds in the area consist of pasture, hay, the straw of barley, oats and teff, and the grains of barley and oats. Pasture grass and other feeds were found to be deficient in Na, P and Mg in relation to dietary requirements. Analyses of blood plasma from crossbred and local cattle showed that a number of samples contained P below the critical level of 1.45 mmol/litre. Effects of year and season were significant for Ca, P, Mg and K. The effect of age was significant for P (P < 0.001). Faecal analyses revealed that about 80% of animals were deficient in Na. Wide variations in the mineral content of soils and lack of significant correlations among soil, pasture and blood plasma indicated that soil and pasture analyses are not reliable in assessing macro mineral status of grazing cattle in this environment. Analyses of bone and blood for Ca and P, blood for Mg and faeces for Na appear to provide better indices.

Animal Feed↗
PubMed1993

A survey of mineral status of soil, feeds and cattle in the Selale Ethiopian highlands. II. Trace elements.

The trace element status of crossbred Friesian x zebu (Boran) and local zebu cattle in the Selale highlands of Ethiopia was evaluated during the rainy and dry seasons of 1989 and 1990 in terms of the trace element content of soils, feeds, blood plasma and faeces on 25 randomly selected farms. Liver samples from animals of local breeds from a slaughter house were collected during the rainy and dry seasons of 1990 and analysed. Soil Fe and Mn were found to be high. Iron contents of all feeds were extremely high and Mn contents were higher than the dietary requirement. A large proportion of feed samples were deficient in Cu and zinc. There were wide variations in the concentrations of these elements among the soil and feed samples. Blood plasma Fe (P < 0.001) and Cu (P < 0.01) values differed significantly between the years. Plasma samples collected during 1990 contained lower mean Cu than 1989. The effect of season was statistically significant (P < 0.001) for all the trace elements. More than half of the animals were found to have low plasma Cu and Zn during the rainy season. Due to lack of any correlations between soil, pasture and blood plasma it is suggested that analyses of soils and pasture are not reliable for assessing the Fe, Cu and Zn status of grazing cattle in the highlands. Analyses of liver and blood appear to provide better indices.

Animal Feed↗
PubMed1992

Ionescu-Shiley valve failure. I: Experience with 125 standard-profile explants.

A group of standard-profile Ionescu-Shiley valve implants, 357 aortic and 190 mitral, was reviewed for cases of failure requiring surgical explantation. To date, 90 (25.2%) of the aortic and 35 (18.4%) of the mitral valves have failed, and are the subject of this analysis. Observations of these explants confirm previous suggestions about the clinical and pathologic patterns of the Ionescu-Shiley valve's failure, but are extended in this study to allow more confident statistical analyses. Cusp tear with insufficiency remains the most important reason for explantation, precipitating removal to date of 19.1% of the aortic and 10.0% of the mitral valves implanted. This difference, aortic versus mitral, is significant (p less than 0.006) and the reverse of observations made in other studies of pericardial valves. In this review there is no significant difference in the proportion of aortic and mitral valves that failed with calcification (2.2% and 3.1%, respectively). Aortic Ionescu-Shiley valves failing with tears had a mean of 3.1 tears per valve, whereas mitral valves had 1.2. Aortic valves also showed considerably more pretear wear than did mitral valves. Although the large number of these Ionescu-Shiley valve failures has been a profound clinical disappointment, it has provided an opportunity to observe and detail the pathology of their failure.

Adolescent↗
PubMed1992

Ionescu-Shiley valve failure. II: Experience with 25 low-profile explants.

A group of patients who had low-profile Ionescu-Shiley valves implanted, 237 aortic and 130 mitral, was reviewed for cases of bioprosthetic failure requiring explantation. Fourteen such aortic and 11 mitral valves were recovered at operation. The most common reason for explantation was valvular insufficiency due to cusp tears, accounting for 50.0% of aortic and 82.0% of mitral explants. Morphologic examination of the valves suggested a common mode of failure with tears, and this is illustrated. The clinical and pathologic patterns of this valve's failure are compared with those of the standard-profile Ionescu-Shiley valve, and many similarities exist. A tendency for a larger proportion of mitral valve failures with tears is, however, in contrast to observations of the standard-profile valve, in which aortic failures are more common. Additionally, low-profile valves, in either the aortic or mitral positions, fail after a shorter time in situ than their standard-profile counterparts, at a mean of 45.1 months versus 78.0 in the aortic position (p less than 0.01) and at 52.2 months versus 73.8 in the mitral position (p less than 0.05). These differences in the performance of the Ionescu-Shiley valve models may have implications for the design of future bioprostheses.

Adult↗
PubMed1992

The University of Ottawa Heart Institute Cardiac Transplant Program: the first 100 transplants. A pathologic study of the explanted hearts.

Since 1984, 122 orthotopic heart transplants have been performed at the University of Ottawa Heart Institute. Of the 114 adult patients, 100 (87.8%) were males and 14 (12.2%) females, with mean ages of 45.8 and 47.9 yr, respectively. The hearts of these adults were pathologically diagnosed as chronic ischemic heart disease (CIHD) in 55 (48.2%), acute ischemic heart disease (AIHD) in 17 (14.9%), dilated cardiomyopathy (DC) in 30 (26.3%), valvular heart disease in five (4.4%), congenital heart disease in three (2.6%), myocarditis in three (2.6%), and other in one (0.9%) of the cases. The adult hearts (94) among the first 100 transplants were studied morphologically, to look for differences among the three major groups with clinical "end-stage" heart failure. The mean heart weights were 435, 356, and 463 gm in the CIHD, AIHD, and DC groups, respectively, with AIHD less than CIHD or DC (p less than 0.01). The ventricular wall thicknesses were similar in CIHD and DC, but the left ventricular (LV) wall thicknesses in AIHD were more than in CIHD or DC (p less than 0.01). The ventricular diameters were greater in DC than in CIHD or AIHD (p less than 0.01) and greater in CIHD than in AIHD (p less than 0.01). The mean LV cavity volumes were 158, 94, and 200 ml in CIHD, AIHD, and DC, respectively, with DC greater than in CIHD or AIHD (p less than 0.01) and CIHD greater than in AIHD (p less than 0.01). The relative differences in AIHD compared to CIHD and DC are referrable to the shorter duration of disease in the acute ischemic group.2+ off

Acute Disease↗
PubMed1990

Estimation of endogenous energy and nitrogen losses in the cockerel during fasting and postprandial.

1. The endogenous energy (EEL) and nitrogen losses of adult cockerels were studied during both when the animals were starved and when they were fed on a highly digestible nitrogen-free diet. The birds were fed three intakes by intubation and the effects of these intakes were compared. 2. During the 48-h study, the excretion of energy (EEL) was found to be 49.4 kJ, when the birds were given food. When starved this estimate was considerably higher, 70.3 kJ. 3. When endogenous energy per 48 h was corrected to zero nitrogen balance (EEL0), the value of starved animals of 30.1 kJ was still considerably higher than the 13.4 kJ for fed birds. 4. It was concluded that feeding a nitrogen free, highly digestible diet reduces the excretion of endogenous energy. Thus determinations from starved birds appear to give biased estimates of EEL and EEL0. Hence, true metabolisable energy values would also be overestimated where endogenous energy values from starved birds were used.

Animal Feed↗