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Biomedical subjects

A Anwar

Publications and source records attributed to A Anwar.

At least 37 records · Page 2Linked to original sources
PubMed2000

Gender differences in the regulation of P450 aromatase expression and activity in human adipose tissue.

OBJECTIVE: To investigate the hormonal regulation of P450 aromatase activity (responsible for the conversion of C19 androgens to C18 oestrogens) in human adipose tissue from men and pre- and post-menopausal women. SUBJECTS: Subcutaneous abdominal adipose tissue was obtained from 19 subjects: six pre-menopausal females (mean age 41.8+/-(s.e.m.) 2.5; mean weight 76.01+/-5.6 kg), eight post-menopausal females (mean age 59.9+/-2.0; mean weight 63.5+/-2.6 kg), and five males (mean age 35.8+/-8.8; mean weight 78.5+/-7.8 kg) undergoing elective or cosmetic surgery. MEASUREMENTS: Cell viability and cell size were determined using staining techniques. RT-PCR was used to confirm the presence of aromatase. The regulation of aromatase activity was characterized using androstenedione as a substrate in a tritiated water release assay. Aromatase activity was analysed in abdominal subcutaneous stromal cells (ASC) and mature adipocytes (AD) cultured in serum-free medium with cortisol (10-6-10-7 M), insulin (500 nM) or a combination of both. RESULTS: In ASC aromatase activity increased in females from 14.5+/-1.7 to 29. 3+/-2.6 pmol/mg/h (n=14, P<0.05) and to 25.2+/-2.1 pmol/mg/h with cortisol (10-7 M) and insulin, respectively (P<0.05). In males ASC basal aromatase activity (20.5+/-4.2 pmol/mg/h; n=5) was inhibited by cortisol (10-7 M) alone (12.3+/-1.8 pmol/mg/h) and in combination with insulin (6.6+/-1.2 pmol/mg/h; men vs women, P<0.005). Aromatase activity in mature adipocytes was stimulated by cortisol plus insulin (P<0.05) with no gender-specific differences. Treatment of ASC from both pre- and post-menopausal females with cortisol alone (10-6 M; 10-7 M) or in combination with insulin demonstrated significantly different aromatase regulation compared with male aromatase stromal cell regulation (P<0.05); however there were no differences in aromatase regulation between pre- and post-menopausal females either in stromal cells or adipocytes. CONCLUSION: This study shows intrinsic gender differences in the regulation of aromatase, suggesting that differential enzyme regulation may affect sex steroid metabolism to alter the pattern of fat distribution between the sexes.

Adipocytes↗
PubMed2000

Alkaline protease from Spilosoma obliqua: potential applications in bio-formulations.

Some properties of the purified alkaline protease from larvae of the insect Spilosoma obliqua (Lepidoptera) and its potential application as an additive in various bio-formulations are reported. The novel feature of the present study is the use of insect protease. The protease was found to be compatible with some of the commercial detergents tested, and was also effective in cleaving various protein substrates tested, albeit to different extents, implying broader substrate specificity and effectiveness of the protease against a wide variety of stains. This property of the protease can also be exploited by using it as an active component in enzymic debriders in view of its ability to digest various protein substrates. The insect protease appears to be potentially useful as an additive in detergent, stain remover and other bio-formulations.

Animals↗
PubMed2000

Insulin-like growth factor binding protein-4 expression is decreased by angiotensin II and thrombin in rat aortic vascular smooth muscle cells.

Insulin-like growth factor-I (IGF-I) is a ubiquitous peptide that regulates cellular growth and differentiation and is involved in vascular proliferative responses. The effects of IGF-I are modulated by several IGF-I binding proteins (IGFBPs), including IGFBP-4, the main IGFBP produced by vascular smooth muscle cells (VSMCs). We have previously shown that angiotensin II (Ang II)-induced and thrombin-induced mitogenesis in VSMCs is dependent on autocrine IGF-I. In addition, we have demonstrated that IGF-I and IGFBP-4 mRNA levels are upregulated in the hypertensive aorta of abdominally coarcted rats, a high-renin hypertension model. To obtain further insight into the IGF-I system and to specifically study changes in IGFBP-4, a known inhibitor of IGF-I action, VSMCs were incubated with Ang II or thrombin. Compared with control, Ang II induced an 87+/-2% downregulation of IGFBP-4 mRNA levels at 24 hours, with a 61+/-6% decrease of IGFBP-4 levels, as determined by Western ligand blot analysis. Thrombin had the same depressor effects (87+/-2% for the mRNA levels and 61+/-3% for the protein levels). Ang II and thrombin coincubation with (125)I-IGFBP-4 in the conditioned media failed to reveal any increase in fragmentation, indicating that proteolytic cleavage of IGFBP-4 was not involved in the observed effects. Exogenous recombinant human IGFBP-4 decreased thrombin-induced DNA synthesis of human aortic VSMCs by 64%, whereas anti-IGFBP-4 antibody potentiated thrombin-induced DNA synthesis. These data suggest that downregulation of IGFBP-4 expression in VSMCs may play a critical role in vascular growth response to Ang II and thrombin in normal and diseased states, by increasing the bioavailability of IGF-I for its cell-surface receptor.

Angiotensin II↗
PubMed2000

Percutaneous vascular surgery after aortic valvuloplasty: initial clinical experience.

Percutaneous balloon aortic valvuloplasty can be associated with significant vascular morbidity. Often, managing the access site prolongs the length of hospitalization. Three patients were successfully treated with percutaneous femoral arterial vascular surgery immediately after aortic valvuloplasty. These patients did not suffer early or late vascular complications. The access site care was dramatically improved when compared to our usual experience.

Aged↗
PubMed1999

Plasma platelet-activating factor acetylhydrolase activity is not associated with premature coronary atherosclerosis.

Platelet-activating factor acetylhydrolase activity in plasma was compared between 72 subjects with angiographically normal coronary arteries and matched controls with clinically significant obstruction. No difference was seen, and we conclude that variation in plasma platelet-activating factor acetylhydrolase activity is not a risk factor for coronary artery disease.

1-Alkyl-2-acetylglycerophosphocholine Esterase↗
PubMed1999

Balloon rupture during stent implantation: A novel technique of salvage with a new manual power injector.

Pinhole leak or rupture of a stent delivery balloon is a well-recognized technical problem encountered in vascular interventions. This event leads to inadequate stent expansion. These stents cannot be fully deployed with the same balloon and frequently the balloon cannot be retrieved without dislodging the stent. We describe a technique for successful stent deployment in such situations using the Oz Power Syringe, a new manual power injector. Cathet. Cardiovasc. Intervent. 48:74-77, 1999.

Aged↗
PubMed1999

Hepatic lipase (LIPC) promoter polymorphism in men with coronary artery disease. Allele frequency and effects on hepatic lipase activity and plasma HDL-C concentrations.

Hepatic lipase is an important determinant of plasma HDL concentration and LDL subclass distribution and may therefore influence susceptibility to coronary artery disease (CAD). To assess the effect of genetic variation in hepatic lipase activity on CAD susceptibility, we determined the frequency of the -514T allele of hepatic lipase in white men with CAD and in controls who did not have CAD. In men with CAD, postheparin plasma hepatic lipase activity was 15% to 20% lower in heterozygotes and 30% lower in homozygotes for the -514T allele. Allele frequencies were similar in cases and controls, however, and were consistent with Hardy-Weinberg expectation in both groups. This finding was confirmed in a second group comprising cases with premature symptomatic CAD and controls who were free of disease. These data indicate that a primary decrease in hepatic lipase activity of as much as 30% does not influence susceptibility to CAD in white men.

Alleles↗
PubMed1999

The use of a new mechanically advantaged syringe for performing coronary intervention.

OBJECTIVE: To determine the utility of a new mechanically advantaged syringe in the performance of percutaneous coronary intervention. BACKGROUND: A new mechanically advantaged syringe has been developed to perform cardiovascular imaging. We wanted to assess the utility of this device in the performance of small catheter percutaneous coronary intervention. Data from coronary interventions performed with the standard technique at our institution, using a 10 ml manual syringe, were compared to the use of a new mechanically advantaged syringe. Contrast utilization during the standard technique was assessed by obtaining data from fifty consecutive successful single-vessel coronary interventions (angioplasty with or without stenting). After an initial learning experience with the mechanically advantaged syringe, fifty consecutive successful single-vessel coronary interventions were assessed. Most interventions performed using the mechanically advantaged syringe were with 6 French catheters. Detailed contrast utilization information was gathered. RESULTS: During the standard method of performing coronary intervention, 216 +/- 114 ml of contrast were used. Utilizing the mechanically advantaged OZ Power Syringe (Cardiovascular Innovations Inc., Athens, Texas), the contrast use was reduced to 66 +/- 39 ml (p < 0.0001) per case. The syringe also allowed excellent visualization despite using a smaller guide catheter system. CONCLUSION: The OZ Power Syringe can be utilized effectively in percutaneous coronary intervention. Our preliminary data suggest that there may be reduced contrast use without sacrificing image quality.

Angioplasty, Balloon, Coronary↗
PubMed1999

Massive thromboembolism due to transcatheter ASD closure with ASDOS device.

Transcatheter occlusion of atrial septal defects (ASD) is currently being investigated as an attractive alternative to surgical correction. Thromboembolic events are rare in both techniques. However, we report a case of massive systemic embolization and residual left atrial thrombus after secundum ASD transcatheter closure by the ASDOS device (Atrial Septal Defect Occlusion System, Dr. Ing Osypka Corporation, Germany). The patient was successfully treated by femoral embolectomies, surgical removal of the device and closure of the ASD without a patch. No thrombophilia was found on subsequent exploration. Transcatheter ASD closure with the ASDOS device may therefore expose the patient to severe embolic complications. Further evaluation is needed before this technique can be safely recommended.

Adult↗
PubMed1998

Epidural ketamine reduces post-operative epidural PCA consumption of fentanyl/bupivacaine.

PURPOSE: To study the analgesic effect of epidural ketamine on postoperative pain and epidural PCA consumption after total abdominal hysterectomy. METHODS: Sixty-one ASA I-II patients, 34-60 yr were randomly assigned into three groups. Epidural catheters were inserted before induction of anaesthesia. Patients in group I and II received 30 mg ketamine epidurally before induction of anaesthesia or 20 min after skin incision: group III received placebo. Postoperatively, on first analgesia request, sedation score, Visual Analogue Scale (VAS), Prince Henry Score (PHS) and Bromage motor weakness score were taken and followed by an epidural bolus of 9 ml bupivacaine 0.25% + 50 micrograms fentanyl. Analgesia was maintained by PCA with a mixture of bupivacaine 0.1% + fentanyl 0.001% epidurally. Measurements were repeated at 1, 2, 4, 8, 12 and 24 hr. RESULTS: First analgesia request was 17 +/- 6.8 min in the control group compared with 31.4 +/- 23.8 and 44 +/- 23.1 min for groups I and II respectively. The differences between group III and group I (P < 0.05) and between group III and group II (P < 0.01) were statistically significant. Twenty four hour PCA consumption was 101.2 +/- 47.2, 87 +/- 27 and 162 +/- 38 ml for groups I, II and III respectively. The differences between group III and group I and that between group III and group II were statistically significant (P < 0.001). CONCLUSION: Epidural ketamine 30 mg reduces post hysterectomy pain as evidenced by prolongation of time to first analgesia request and reduction in postoperative epidural PCA consumption. This effect is manifest whether ketamine is given before induction or 20 min after skin incision.

Adult↗
PubMed1998

Role of naturally occurring autoantibodies in senescence of normal and ATP depleted goat erythrocytes.

The possible role of autoantibodies in the senescence of goat erythrocytes has been investigated. For this purpose goat gammaglobulin was purified to homogeneity and antigoat gammaglobulin was raised in rabbits. Using the peroxidase labelled antigoat gammaglobulin it was possible to detect the presence of auto anti band-3 antibodies in goat sera. The goat erythrocytes were aged in vitro by ATP-depletion, which resulted in appearance of a 52,000 mol. wt. polypeptide. The in vitro aged goat erythrocyte membrane bound substantial amounts of auto anti band-3 antibodies as visualized by immunoblots.

Adenosine Triphosphate↗
PubMed1998

Structure of an ovine CYP11B1 gene.

Glucocorticoids play an important role in the normal development and proliferation of cells, and are also involved in inflammatory responses. The level of active glucocorticoids in the body is controlled in part by the enzyme CYP11B1, which catalyses the final step of its biosynthesis. In this report, we have completely characterised the ovine CYP11B1 gene using two overlapping clones isolated from an lambdaEMBL3 sheep liver genomic library. The gene comprised 9 exons and 8 introns, spanning over a region of 8.0 kb. Two ovine CYP11B1 transcripts, with molecular sizes of 1.9 and 4.0 kb, have also been isolated from the adrenal zona fasciculata region, which showed that they arose from the usage of the two polyadenylation sites situated 2.1 kb apart in exon 9. The transcriptional start sites of the gene has been mapped using primer extension analysis. Three major start sites were identified at positions -5, -6 and -77 from the first ATG codon (Met), with two minor sites located at positions -306 and -413. When examined in context with the ovine CYP11B1 5' regulatory region, the results suggested that the ovine CYP11B1 gene contained two additional core promoters located further upstream of a proximal TATA box which could be utilised to produce mRNAs with alternative transcriptional start sites.

Adrenal Cortex Hormones↗
PubMed1996

Insulin-like growth factor 1 binding protein 3 synthesis by aortic endothelial cells is a function of cell density.

Proliferating bovine aortic endothelial cells in culture do not express the insulin-like growth factor 1 binding protein 3 gene, in contrast to the genes encoding binding proteins 2, 4, 5, and 6. The binding protein 3 gene is activated only at cell confluency with continual transcription thereafter, for at least an eight-day post-confluent period, both in the presence or absence of serum. Secretion of protein product into the medium parallels transcription. DNA synthesis is inversely related to the amount of total insulin-like growth factor 1 binding protein 3 in the culture medium. The addition of anti-binding protein 3 antibody to media significantly increases the rate of DNA synthesis by extensively post-confluent cells. These data suggest (1) aortic endothelial cells are an important source of circulating binding protein 3, (2) binding protein 3 has an inhibitory effect upon the growth of endothelial cells, (3) the triggering of binding protein 3 synthesis after confluency suggests a role in maintaining the growth-arrested monolayer state of the cells in vivo.

Animals↗
PubMed1996

G-protein coupled and tyrosine kinase receptors: evidence that activation of the insulin-like growth factor I receptor is required for thrombin-induced mitogenesis of rat aortic smooth muscle cells.

IGF I is an ubiquitous peptide that activates a membrane tyrosine kinase receptor and has autocrine/paracrine effects on vascular smooth muscle cells. Thrombin activates a G-protein coupled receptor and is also a mitogen for vascular smooth muscle cells. To assess the potential role of IGF I as a mediator of thrombin's effects, we characterized expression of IGF I and of its receptor on vascular smooth muscle cells exposed to thrombin. Thrombin dose-dependently decreased IGF I mRNA levels and caused a delayed decrease in IGF I secretion from vascular smooth muscle cells. This effect was mimicked by the hexapeptide SF-FLRN (that functions as a tethered ligand) and was inhibited by hirudin. In contrast, thrombin doubled IGF I receptor density on vascular smooth muscle cells, without altering binding affinity (Kd). An anti-IGF I antiserum markedly reduced thrombin-induced DNA synthesis, whereas nonimmune serum and an anti-fibroblast growth factor antibody were without effect. Cell counts confirmed these results. Downregulation of IGF I receptors by antisense phosphorothioate oligonucleotides likewise markedly inhibited thrombin-induced DNA synthesis. These data demonstrate that a functional IGF I-IGF I receptor pathway is essential for thrombin-induced mitogenic signaling and support the concept of cross talk between G-protein coupled and tyrosine kinase receptors.

Amino Acid Sequence↗
PubMed1996

Distal vessel pullback angiography and pressure gradient measurement: an innovative diagnostic approach to evaluate the no-reflow phenomenon.

The angiographic appearance of "no-reflow" in saphenous vein grafts or native coronary arteries has been described following administration of thrombolytic therapy or performance of percutaneous transluminal coronary angioplasty or atherectomy. Apparent occlusion may represent spasm, dissection, thrombosis, or competitive collateral circulation, all of which must be excluded to make the diagnosis of "no-reflow." We describe an innovative approach to the diagnostic dilemma created by the appearance of "no-reflow" at coronary angiography. Pressure gradient measurement with distal vessel pull-back (retrograde) angiography provides maximal information regarding the severity of disease and the etiology of "no-reflow," while exposing both the patient and angiographer to less risk compared to standard strategies.

Angioplasty, Balloon, Coronary↗
PubMed1994

Coronary stenting with a new ultra-short balloon expandable device: early and late animal results.

The early and late effects of a new balloon-expandable coronary stent (Boneau II) were studied in 16 adult mongrel dogs. Thirty-three balloon-expandable stents were deployed using standard transfemoral coronary angioplasty technique. Single stents were placed in eight dogs and multiple (two to four) stents were placed in eight dogs. Intravenous heparin (3,000 units) was administered at the beginning of the procedure. Aspirin, dipyridamole, dextran, and warfarin were not administered before or after the procedure. All stent deployments were successful. Angiographic or pathologic examinations were performed within 24 hr of deployment on two of the dogs, at 2 weeks on two of the dogs, at 2 months on three of the dogs, at 6 months on six of the dogs, and at 1 year on three of the dogs. All successfully deployed stents were noted to be widely patent. There was no evidence of side-branch vessel occlusion. There was no evidence of acute or late vessel thrombosis. Histologic examination at 2 months showed a mean intimal thickness of 153 microns. The stainless steel Boneau II coronary stent is relatively short and easily deployed. This balloon-expandable coronary stent was successfully deployed in normal canine arteries without the use of anticoagulation or antiplatelet therapy before or after the procedure. The Boneau II intracoronary stent has a very low thrombogenic potential in dogs.

Angioplasty, Balloon, Coronary↗