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Biomedical subjects

A Mustafa

Publications and source records attributed to A Mustafa.

At least 19 recordsLinked to original sources
PubMed2005

Application of urea based SNCR system in the combustion effluent containing low level of baseline nitric oxide.

Selective Non-Catalytic Reduction (SNCR) of nitric oxide has been studied experimentally by injecting aqueous urea solution with and without additive in a pilot-scale diesel fired tunnel furnace at 3.4% excess oxygen level and with low ppm of baseline NO(x) ranging from 65 to 75 ppm within the investigated temperature range. The tests have been carried out using commercial grade urea as NO(x) reducing agent and commercial grade sodium carbonate as additive. The furnace simulated the small-scale combustion systems, where the operating temperatures are usually in the range of about 973 to 1323 K and NO(x) emission level remains below 100 ppm. With 5% plain urea solution, at Normalized Stoichiometric Ratio (NSR) of 4 as much as 54% reduction was achieved at 1128 K, whilst in the additive case the NO(x) reduction was improved to as much as 69% at 1093 K. Apart from this improvement, in the additive case, the effective temperature window as well as peak temperature of NO(x) reduction shifted towards lower temperatures. The result is quite significant, especially for this investigated level of baseline NO(x). The ammonia slip measurements showed that in both cases the slip was below 16 ppm at NSR of 4 and optimum temperature of NO(x) reduction. Finally, the investigations demonstrated that urea based SNCR is quite applicable to small-scale combustion applications and commercial grade sodium carbonate is a potential additive.

Ammonia↗
PubMed2004

Treatment of acute mastoiditis: report of 31 cases over a ten year period.

OBJECTIVE: With possible extracranial and intracranial complications, acute mastoiditis is the leading complication of acute otitis media (AOM). The goal of this study is to assess the clinical features, pathogens, complications and especially management of acute mastoiditis in the ENT service, University Hospital of Strasbourg, France. METHODS: Systematic review of all medical records of patients who were admitted with acute mastoiditis from January 1993 to April 2003. RESULTS: 31 patients, 18 male (58%) and 13 female (42%) fulfilled inclusion criteria. The average age was 16, going from 6 months to 70 years, with 55% between 0 to 5 years. Most common symptom was otalgia (84%), 58% of patients had history of past AOM and 61% were under antibiotic therapy during admission. Twenty-three patients (74%) presented retroauricular swelling and erythema. 18 (58%) had a displaced pinna. Cultures taken from pus isolated Streptococcus pneumoniae in 12 cases (38.7%), Pseudomonas aeruginosa in 2 cases (6.4%), Streptococcus beta-haemolyticuis 1 case, Staphylococcus coagulase-positive 1 case and Mycobacterium tuberculosis hominis 1 case (3%). Complications of acute mastoiditis occurred in 3 cases (10%): Meningitis 2 cases and facial nerve paralysis 1 case. Surgery therapy was periformed in 84% of cases (mastoidectomy only or in combination with myringotomy with tube insertion) and medical therapy only in 16% of cases. CONCLUSION: Despite use of antibiotics, acute mastoiditis remains still a threat for patients with AOM, especially for children under 5 years of age. Great care is required from clinicians to make an early diagnosis in order to promote adequate management and prevent complications.

Acute Disease↗
PubMed2004

Tuberculous acute mastoiditis--a rare diagnosis. A case report.

Tuberculous acute mastoiditis (TAM) is a rare inflammatory infective condition of the mastoid process that can be difficult to diagnose. We presente the case of a 65-year-old women with earache, ear purulent discharge and tenderness of the mastoid tip after long time of medical therapy. Mastoidectomy with attico-antrotomy revealed chronic granulations with an osteitic process of mastoid and tympanic cavity with intact ossicular chain. Standard medical therapy resulted with prompt healing. Despite its rarity, diagnosis of TAM is often delayed, with potentially danger for severe complications.

Aged↗
PubMed2002

Skin morphology and humoral non-specific defence parameters of mucus and plasma in rainbow trout, coho and Atlantic salmon.

Susceptibility to different diseases among related species, such as coho salmon (Oncorhynchus kisutch), rainbow trout (Oncorhyncus mykiss) and Atlantic salmon (Salmo salar), is variable. The prominence of these species in aquaculture warrants investigation into sources of this variability to assist future disease management. To develop a better understanding of the basis for species variability, several important non-specific humoral parameters were examined in juvenile fish of these three economically important species. Mucous protease, alkaline phosphatase and lysozyme, as well as plasma lysozyme activities and histological parameters (epidermal thickness and mucous cell density, and size) were characterized and compared for three salmonids: rainbow trout, Atlantic salmon and coho salmon. Rainbow trout had a thicker epidermis and significantly more mucous cells per cross-sectional area than the other two species. Rainbow trout also had significantly higher mucous protease activity than Atlantic salmon and significantly higher lysozyme (plasma and mucus) activities than coho and Atlantic salmon, in seawater. Atlantic salmon, on the other hand, had the lowest activities of mucous lysozyme and proteases, the thinnest epidermal layer and the sparsest distribution of mucous cells, compared with the two other salmonids in seawater. Only coho salmon had sacciform cells. Atlantic and coho salmon had higher mucous lysozyme activities in freshwater as compared to seawater. There was no significant difference between mucous lysozyme activities in any of the three species reared in freshwater; however, rainbow trout still had a significantly higher plasma lysozyme activity compared with the other two species. All three species exhibited significantly lower mucous alkaline phosphatase and protease activities in freshwater than in seawater. Our results demonstrate that there are significant histological and biochemical differences between the skin and mucus of these three salmonid species, which may change as a result of differing environments. Variation in these innate immune factors is likely to have differing influences on each species response to disease processes.

Alkaline Phosphatase↗
PubMed2002

The glutamate transporter GLAST-1 (EAAT-1) is expressed in the plasma membrane of osteocytes and is responsive to extracellular glutamate concentration.

The glutamate/aspartate transporter GLAST-1 is expressed in bone in vivo and also exists as a splice variant (GLAST-1a) in which exon 3 is excluded. Since GLAST-1 expression is regulated in bone in response to osteogenic mechanical stimuli in vivo and binding of glutamate to receptors on osteoblasts increases osteoblast number and activity in vitro, control of extracellular glutamate concentrations may be critical for balanced bone remodelling. To determine whether GLAST isoforms may act to regulate extracellular glutamate concentration in bone we investigated whether their pattern or level of expression is responsive to glutamate concentration in bone cells. GLAST-1a mRNA is expressed at lower levels than GLAST-1 mRNA in all cells examined. The GLAST-1a/GLAST-1 mRNA ratio is greater in MLO-Y4 osteocytes than in SaOS-2 osteoblast-like cells, although this does vary in SaOS-2 cells in response to extracellular glutamate concentration. Transfection of MLO-Y4 cells with green fluorescent protein (GFP)-tagged GLAST isoforms revealed a plasma membrane localization of GLAST-1, consistent with its transporter function, whereas GLAST-1a appeared to be expressed within internal vesicles. Interestingly, low extracellular glutamate concentrations redistributed GLAST-1-GFP into a similar internal expression pattern. Regulation of the expression and distribution of GLAST-1 by extracellular glutamate in bone cells indicates that it may regulate glutamate signalling in bone, consistent with its operation in the central nervous system.

Animals↗
PubMed2002

Reducing waiting times associated with an integrated child health service.

Following an increase in average waiting times associated with a child health service in East London, an initiative to rapidly reduce the numbers of children waiting long periods following a referral was undertaken over the period May to June 1999. A multidisciplinary cooperative approach was adopted operating within the existing available resources and involved medical, nursing, managerial and administrative staff. The initiative involved a review of the accuracy of the waiting list, followed by an invitation to remaining patients to provide an option of continuing to wait to be seen or offering attendance at a rapid response clinic associated with reduced waiting and consultation times. Half-hourly appointments were routinely offered instead of hourly appointments and proformas were adopted for history taking and onward referrals to save time spent on administration. A total of 162 patients were seen over the course of a month and a satisfaction questionnaire completed by relatives indicated a preference for the new service. The mean waiting time was reduced to under a quarter of the time at the start of the initiative to a mean of less than two months. The purpose of the study was to see if the waiting list could be reduced by using existing staff. We wanted to ascertain the parents' views whether shorter waits and shorter consultation periods were acceptable, and to ascertain if the waiting list could be kept down or whether the waiting list would rapidly recur after the rapid response clinics stopped. The findings are discussed in relation to initiatives elsewhere and the need to maintain a high quality service.

Adolescent↗
PubMed2001

The effect of ovariectomy and ovarian steroid treatment on growth hormone and insulin-like growth factor-I levels in the rat femur.

Growth hormone (GH) and insulin-like growth factor-I (IGF-I) are known to play an important role in bone metabolism. The regulation of plasma levels of GH and IGF-I by ovarian steroids is well known, however, their effect on local GH and IGF-I is still unclear. In this study, we investigated the effect of ovariectomy and ovarian steroid treatment on the femur GH and IGF-I levels as well as on bone density in the rat. Nine month-old rats were ovariectomized (OVX) or sham-operated (SHAM) and 9 weeks after the surgery they were treated with daily s.c. injections of either 17beta-estradiol (OVX + E), progesterone (OVX + P), or vehicle (OVX + V) for another 10 weeks. GH and IGF-I levels in the femur extracts were measured by specific radioimmunoassay (RIA). Ovariectomy decreased GH and had no effect on IGF-I levels. Estradiol treatment increased femur GH and IGF-I levels compared to SHAM rats. Progesterone restored GH and increased IGF-I levels. Ovariectomy decreased, estrogen restored and progesterone partially restored femur bone density. Our results demonstrate that ovariectomy and ovarian steroids modulate the levels of GH and IGF-I in the bone of aged OVX rats. However, these effects appear to be limited to supraphysiological concentrations of estradiol and progesterone.

Animals↗
PubMed2001

Reduced levels of insulin-like growth factor-1 receptor (IGF-1R) suppress cellular signaling in experimental autoimmune sialadenitis (EAS).

The nonobese diabetic mouse (NOD) develops destruction and functional impairment of salivary and lachrymal glands, experimental autoimmune sialadenitis (EAS), resembling and representing a model for Sjogren's syndrome (SS). To investigate the mechanisms of tissue destruction in EAS, we analyzed a cell survival promoter insulin-like growth factor-1 receptor (IGF-1R) in the submandibular glands of NOD mice with this disease. We also evaluated the expression of a downstream effector of IGF-1R, BAD. Receptor-binding autoradiography revealed that the IGF-1R levels in submandibular glands from young NOD mice were lower than those in adult NOD mice. Immunofluorescence staining demonstrated that BAD expression in the epithelial cells of the submandibular gland was consistently enhanced throughout the course of EAS in NOD mice. These findings suggest that a reduction in the levels of IGF-1R induces a defective glandular homeostasis in the submandibular gland epithelial cells and triggers EAS.

Animals↗
PubMed2001

Circulating immune complexes induced by food proteins implicated in precocious myocardial infarction.

BACKGROUND: Circulating immune complexes (CIC) are frequently found in postinfarction patients. The constituents of these CIC are mostly unknown. AIM: The objective of the current study was to assess whether CIC containing alimentary proteins and antibodies against these proteins are implicated in precocious myocardial infarction (MI). METHODS: Seventy-six survivors (67 men and 9 women, mean age 39 years) of a first MI before the age of 45 years were enrolled in this study. Two control groups were included. One group consisted of age-matched, randomly selected, population-based healthy individuals, 79 men and 11 women, without features of coronary heart disease. An additional control group was used only for the determination of serum antibodies against some of the alimentary proteins and consisted of 139 healthy blood donors, 95 men and 44 women, with a mean age of 42 years. Sucrose density gradient centrifugation, gel filtration and precipitation by polyethylene glycol were used for the isolation of CIC, and enzyme-linked immunosorbent assay (ELISA) was used to measure the immunoglobulin levels and specific antibodies against alimentary proteins in both sera and isolated CIC. Sodium dodecylsulfate (SDS) polyacrylamide gel electrophoresis and Western blotting were used to determine alimentary proteins in the CIC. RESULTS: Alimentary antigens/antibodies were present in immune complex form in seven out of 14 (50%) postinfarction patients who had persistent high concentrations of CIC, the latter constituting 18% of the entire group. Antibodies of the IgG isotype predominated. A rise in CIC, signs of activation of the classical complement pathway, and a rise in plasma concentrations of von Willebrand factor antigen (vWFAg) were evident within 1 week in four patients subjected to a 2-week elimination diet followed by a single challenge with cow's milk. CONCLUSION: This study suggests that dietary proteins occasionally give rise to persistent CIC, which may predispose to MI at a young age.

Adult↗
PubMed2001

Estimating the cost of sea lice to salmon aquaculture in eastern Canada.

Parasitic sea lice are serious problems in aquaculture. The true cost of these parasites is unknown. We demonstrate the economic burden imposed by sea lice, so that researchers, aquatic specialists, and policy makers can approximate the economic cost of this problem and work towards developing alternative control methods.

Animals↗
PubMed2000

Circulating immune complexes in 50-year-old men as a strong and independent risk factor for myocardial infarction.

BACKGROUND: Circulating immune complexes (CICs) and autoantibodies against oxidatively modified LDLs (oxLDLs) and cardiolipin occur in patients with atherosclerosis and myocardial infarction (MI). The ability of such CICs and antibodies to predict myocardial infarction (MI) was investigated in a prospective nested case-control study in which healthy 50-year-old men were followed for 20 years. METHODS AND RESULTS: Two hundred fifty-seven men were included in the study, and 119 developed MI (39 died) between 50 and 70 years of age. One hundred thirty-eight randomly chosen men who did not develop MI up to 70 years of age served as controls. The prevalence of elevated levels of CICs and the concentration of CICs in men who developed MI were higher than in those who remained healthy. The concentration of CICs at age 50 was associated with a marked increased risk for MI, and this risk was independent of other conventionally recognized risk factors. There was a positive correlation between the levels of CIC and IgG antibodies to cardiolipin in men who developed MI. The level of IgG antibodies and the prevalence of elevated IgG and IgM antibodies to cardiolipin were higher in those who developed MI and had CICs than in those without CICs. Among men homozygous for C4 null alleles, those who developed MI had higher concentrations of CICs than did those who remained healthy. CONCLUSIONS: This prospective study shows that CICs alone or in combination with autoantibodies against cardiolipin in healthy males at 50 years of age predict subsequent MI between the age of and 70 years.

Aged↗
PubMed2000

Muscarinic M3 receptor subtype gene expression in the human heart.

The heart is an important target organ for cholinergic function. In this study, muscarinic receptor subtype(s) in the human heart were determined using reverse transcription-polymerase chain reaction. Our results demonstrated muscarinic receptor M2 and M3 subtype RNA in left/right atria/ventricles of donor hearts. Receptor autoradiography analysis using selective muscarinic ligands indicated an absence of M1 receptor subtype in the human heart. The level of muscarinic receptor binding in atria was two to three times greater than in ventricles. Our results suggest that muscarinic receptors in the human heart are of the M2 and M3 subtypes. This is the first report of M3 receptors in the human myocardium.

Adolescent↗
PubMed2000

Effects of sea lice (Lepeophtheirus salmonis Kröyer, 1837) infestation on macrophage functions in Atlantic salmon (Salmo salar L.).

Experiments were conducted to determine the effects of sea lice, Lepeophtheirus salmonis, on non-specific defence mechanisms in Atlantic salmon, Salmo salar, by experimentally infesting hatchery-reared 1 and 2 year old post-smolts, S1 and S2, with laboratory grown infective copepodids at moderate to high infection intensities ranging from 15-285 lice per fish. The effects of sea lice-induced stress were investigated by measuring the blood levels of cortisol and glucose as indicators of primary and secondary stress responses, and by changes in macrophage respiratory burst activity and phagocytosis as indicators of tertiary stress responses as well as non-specific defence mechanisms. Fish were sampled prior to sea lice infestation at day 0 and at days 3, 7, 14 and 21 post-infestation. Sea lice were at copepodid stage at day 3, at chalimus stages at days 7 and 14, and at pre-adult stage at day 21. Blood levels of cortisol and glucose were found to be significantly increased at day 21 in fish-infested with the highest levels. Macrophage respiratory burst and phagocytic activities were found to be significantly decreased only at day 21. These results indicate that sea lice do not suppress host defence mechanisms during the earlier stages of infestation. They do have effects on the development of chronic stress and on the host non-specific defence mechanisms soon after the lice reach the pre-adult stage.

Age Factors↗
PubMed2000

Modulation of early immune responses and suppression of Trypanosoma brucei brucei infections by surgical denervation of the spleen.

OBJECTIVE: To examine critical interactions between the nervous system and the immune system during experimental African trypanosomiasis. METHODS AND RESULTS: Inoculation of Trypanosoma brucei brucei resulted in early interferon (IFN)-gamma production, elevated corticosterone and prostaglandin E(2) (PGE(2)) levels and increased splenocyte proliferation, as measured by enzyme-linked immunospot assay, radioimmunoassay and thymidine incorporation assay, respectively. Splenic denervation suppressed IFN-gamma, corticosterone and PGE(2) production, enhanced splenocyte proliferation, and significantly reduced parasitemia and prolonged rat survival. CONCLUSIONS: Our data show substantial effects of the nervous system on early immune responses that may influence the outcome of this disease. These effects were not dependent on cytokine inhibitory mediators such as prostaglandins or stress hormones. More investigations are required to understand the evident neural control over the immune system during infectious challenges, which may assist in novel therapeutic approaches.

Animals↗
PubMed1999

Cytokinetics of a novel 1,2,3-triazene-containing heterocycle, 8-nitro-3-methyl-benzo-1,2,3,5-tetrazepin-4(3H)-one (NIME), in the human epithelial ovarian cancer cell line OVCAR-3.

The mechanism of action of the novel tetrazepinone 8-nitro-3-methyl-benzo-1,2,3,5-tetrazepin-4(3H)-one (NIME), structurally related to the antitumour drug temozolomide, was studied in the human ovarian tumour cell line OVCAR-3. NIME preferentially inhibited DNA synthesis over protein and RNA syntheses at 3 and 24 hr post-treatment. A Maxam-Gilbert sequencing assay showed that NIME induced barely detectable levels of guanine N7 alkylation in an isolated DNA strand, in contrast to temozolomide, a strong alkylating agent containing, like NIME, a cyclic 3-methyl-1,2,3-triazene moiety. Alkaline sucrose density-gradient sedimentation, at concentrations 2- to 10-fold lower than the ones used in the DNA sequencing assay, showed significant DNA damage in OVCAR-3 cells 24 hr after treatment with NIME. This was accompanied by a significant accumulation of cells in late S and G2M. Cell cycle arrest was transient and was reversed after 2-3 days following drug treatment. This was in agreement with bivariate bromodeoxyuridine/propidium iodide analysis, which showed that at 100 microM, a concentration at which the majority of the cells arrested in late S and G2M, a significant fraction of bromodeoxyuridine positive (S-phase) cells escaped the block. In an attempt to elucidate the mechanism underlying these effects, the degradation of NIME in cell culture medium was analyzed by GC-MS (gas chromatography coupled with mass spectrometry). The results showed that, in contrast to temozolomide, NIME did not convert to an open-chain alkyltriazene in cell culture medium, but to a major benzimidazole product, which exerted a minor effect on the cell cycle. This suggests that NIME, despite containing a 3-(alkyl)-1,2,3-triazene moiety, does not act by DNA alkylation but probably by generating a short-lived genotoxic species during its degradation to 6,5-benzofused derivatives.

Alkylation↗
PubMed1999

Circulating immune complexes and complement C4 null alleles in patients in patients operated on for premature atherosclerotic peripheral vascular disease.

Circulating immune complexes can lead to vascular inflammation and premature atherosclerosis and the fourth component of complement, C4, plays an important role in the removal of immune complexes. The objective of this study was to analyze the relation between circulating immune complexes and C4 null alleles in patients operated on for peripheral vascular disease before the age of 50. The prevalence of circulating immune complexes and null alleles of C4 (C4Q0) was determined in 62 patients with peripheral atherosclerosis requiring surgery before 50 years of age and in a matched control group. C4A and C4B null alleles (C4A*Q0, C4B*Q0) were determined by electrophoresis of plasma, followed by immunofixation. C4A and C4B concentrations were measured by ELISA. Circulating immune complexes were determined by sucrose density gradient centrifugation and gel filtration. There was no difference in the distribution of C4Q0 between patients and controls. The patients had higher prevalences and levels of circulating immune complexes. This was correlated with the presence of C4Q0, especially C4A*Q0. There was an inverse correlation of concentration of circulating immune complexes with C4A levels and with ratio of C4A/B levels. Thus, a significant proportion of patients with premature peripheral atherosclerosis had circulating immune complexes and C4A*Q0 enhanced the propensity to immune complex formation. This might represent one mechanism for vascular damage in this patient group.

Adult↗
PubMed1999

Anti-cardiolipin antibodies and circulating immune complexes in type 1 diabetes mellitus: increased prevalence and relation to vascular complications.

Anti-cardiolipin antibodies, oxidatively modified low-density lipoproteins (oxLDL) and circulating immune complexes are humoral factors that have been linked to vascular damage. To analyse their possible role in the vascular complications in type 1 diabetes mellitus, we investigated patients with and without vascular complications (retinopathy, nephropathy, polyneuropathy, foot ulcers). The patients were matched for age, sex and duration of diabetes. The patients were also compared with 102 healthy individuals. Anti-cardiolipin antibodies of IgG and IgA type were more common in patients compared with healthy individuals. There was no difference between patients with and without vascular complications. There was no increased prevalence of IgM anti-cardiolipin antibodies, but the levels of these antibodies were higher in patients with vascular complications compared with patients without complications and controls. Eighty-three percent of patients had circulating immune complexes in comparison with 5% of healthy individuals. Such complexes were more common in patients with complications. Both the prevalence and the levels of immune complexes were higher in patients with null alleles of complement factor C4. Patients with vascular complications had higher prevalence of C4A than of C4B null alleles. Anti-cardiolipin antibodies were present in higher relative concentrations in immune complex form than in serum in all six patients analysed. There was no increased prevalence of antibodies against oxidatively modified LDL in the patients. The higher prevalence and levels of anti-cardiolipin antibodies and circulating immune complexes in patients with vascular complications suggests that these humoral factors might be involved in the vascular complications of type 1 diabetes mellitus.

Adult↗