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Biomedical subjects

M A Hussain

Publications and source records attributed to M A Hussain.

At least 19 recordsLinked to original sources
PubMed2006

The study of neural network-based controller for controlling dissolved oxygen concentration in a sequencing batch reactor.

The design and development of the neural network (NN)-based controller performance for the activated sludge process in sequencing batch reactor (SBR) is presented in this paper. Here we give a comparative study of various neural network (NN)-based controllers such as the direct inverse control, internal model control (IMC) and hybrid NN control strategies to maintain the dissolved oxygen (DO) level of an activated sludge system by manipulating the air flow rate. The NN inverse model-based controller with the model-based scheme represents the controller, which relies solely upon the simple NN inverse model. In the IMC, both the forward and inverse models are used directly as elements within the feedback loop. The hybrid NN control consists of a basic NN controller in parallel with a proportional integral (PI) controller. Various simulation tests involving multiple set-point changes, disturbances rejection and noise effects were performed to review the performances of these various controllers. From the results it can be seen that hybrid controller gives the best results in tracking set-point changes under disturbances and noise effects.

Algorithms↗
PubMed2006

Prevalence study to elucidate the transmission pathways of Helicobacter pylori at oral and gastroduodenal sites of a South Indian population.

INTRODUCTION: Since the discovery of Helicobacter pylori (H. pylori), much progress has been made worldwide in the field of its epidemiology. In spite of these advancements, many aspects of epidemiology still remain unclear, particularly among populations with low socio-economic status. The present study was designed to elucidate the different routes of transmission of H. pylori in the Hyderabad (South India) population and to investigate the impact of certain factors, such as age, gender, and lifestyle. METHODS: Samples used for the study included saliva and biopsy samples of 400 symptomatic subjects from Hyderabad, India. The patients were retrospectively grouped, based on histopathology of the biopsy and 16S rRNA amplification of both saliva and biopsy as H. pylori positive and negative. RESULTS: This study showed that the prevalence of H. pylori in both saliva and biopsy samples increased with age. In addition, the H. pylori infection was found more commonly in the saliva and biopsy samples among males (64 percent and 60 percent, respectively) than females (53.3 percent and 64 percent, respectively). Similarly, 71.6 percent and 73.5 percent of those who consumed municipal water acquired H. pylori (which were respectively found in their saliva and biopsy samples) compared to a lesser proportion (12.6 percent and 12.6 percent, respectively) of those who consumed boiled or filtered water. The study also found that subjects who preferred home-cooked food (57.1 percent and 57.7 percent) showed a lower prevalence of H. pylori in saliva and biopsy samples, respectively, compared to those (80 percent and 88 percent) who frequently ate out. CONCLUSION: The results of the present study suggest that besides the oral-oral route, the transmission of H. pylori also takes place through the consumption of food prepared under unhygienic conditions. Consumption of municipal tap water also has a high impact in the transmission of H. pylori.

Adolescent↗
PubMed2005

Rapid diagnosis of Helicobacter pylori infection in dyspeptic patients using salivary secretion: a non-invasive approach.

INTRODUCTION: Current guidelines that recommend Helicobacter pylori eradication treatment without endoscopy in selected patients underscore the importance of non-invasive testing. The accuracy of saliva as a non-invasive specimen was compared with that of invasive tests in pretreatment diagnosis of H. pylori infection. METHODS: One hundred patients undergoing gastroscopy were grouped into 80 symptomatic and 20 asymptomatic subjects and were investigated for the presence of H. pylori in saliva and stomach. Samples tested comprised saliva and gastric biopsies collected from each patient. Exclusion criteria were history of peptic ulcer, bleeding ulcer, cancer or recent use of antibiotics, proton pump inhibitors and non-steroidal anti-inflammatory drugs. Two sets of primers homologous to 534 bp fragment of H. pylori DNA, which have been shown previously to be highly specific and sensitive, were used for the polymerase chain reaction (PCR) amplification. RESULTS: 72 (90 percent) of the symptomatic group and 10 asymptomatic subjects were infected with H. pylori in the stomach as determined by histology and direct PCR amplification of biopsy DNA obtained from each subject. H. pylori DNA was identified in the saliva of 70 (87.5 percent) symptomatic subjects and 12 (60 percent) asymptomatic control subjects. CONCLUSION: High rates of detection using saliva as a specimen indicate that saliva of the infected person could serve as a reliable non-invasive alternative to detect the presence of H. pylori infection in comparison to the currently available standard diagnostic tests.

Adult↗
PubMed2004

A decrease in effective diameter of rat mesenteric venules due to leukocyte margination after a bolus injection of pentoxifylline--digital image analysis of an intravital microscopic observation.

The ability of leukocytes to adhere to endothelial cells (EC) and then to migrate out of the blood stream into tissues enable them to perform their surveillance functions. Adhesion of leukocytes to EC is, however, only possible if the cells have marginated as a result of rheological interaction with other blood cells in flow. Using Pentoxifylline (PTX), a rheologically active drug, to manipulate this interaction, we have imaged and quantified this margination phenomenon in vivo. A system has been developing to perform this imaging via an intravital microscope connected to an image processing system. Albino rats were anesthetized and cannulated for intravenous bolus injection (0.5 ml) of PTX (1.25 mg/ml) through the femoral vein. A longitudinal incision exposed the mesentery, part of which was observed under microscope to visualize microcirculation. The image of interest was then stored on computer hard drive. Individual leukocyte velocities were determined before and after PTX infusion. The leukocytes, marginating and sticking after PTX infusion either remained attached, constituting the peripheral marginating leukocyte pool in the postcapillary venules, or detached with different step velocities. The reduction in effective venular diameters as a result of leukocyte margination was estimated to be 32-44%. These results demonstrate the biological importance of hemodynamic displacement leading to docking, adhesion, rolling and migration processes of leukocytes in blood.

Animals↗
PubMed2002

Fluid bed granulation of a poorly water soluble, low density, micronized drug: comparison with high shear granulation.

A 2(4-1) fractional factorial design was used to evaluate the effect of various process variables in fluid bed granulation, on the physico-chemical properties of granule and tablet containing a high dose, poorly water soluble, low density, and micronized drug. The process variables studied were inlet air temperature, inlet air flow, spray rate of the binder solution, and atomization air pressure. Tablets with identical composition, weight, size and hardness were also manufactured in a high shear granulator and their physical properties were determined and compared with those produced by the fluidized bed granulation method. Except for the granule size distribution, other physical properties of granulations and tablets produced in a fluid bed granulator are independent of the selected process variables within the study range. Both atomization air pressure and spray rate of the binder solution had strong impact on granule size distribution. Irrespective of the process conditions used in the fluid bed granulation, granules from this process were more porous, less dense and more compressible than the granules from the high shear granulation process. Comparable tablet dissolution rates to those prepared by the optimized high shear granulation method can be achieved by selecting the appropriate process conditions in fluid bed granulation. These results suggest that wet granulation tablets of a high dose, poorly water soluble, low density, micronized drug can be manufactured using a fluidized bed granulation method, with comparable tablet dissolution rates to those produced with an optimized high shear granulation method.

Powders↗
PubMed2001

Resistance to nonspecific protein adsorption by poly(vinyl alcohol) thin films adsorbed to a poly(styrene) support matrix studied using surface plasmon resonance.

Thin films of poly(vinyl alcohol) (PVA) polymer were prepared on a flat, nonporous, poly(styrene) support matrix by adsorption from aqueous solution and were characterized in order to investigate the nonspecific adsorption of proteins to a chromatographically relevant surface. The integrity and surface coverage of the PVA thin films were established by surface analysis and atomic force microscopy imaging. The adsorption of the PVA polymers to the poly(styrene) substrate and the nonspecific adsorption of proteins to the PVA-coated surface were monitored using surface plasmon resonance. PVA was strongly bound to the poly(styrene) surface, but the surface density of the adsorbed PVA polymers was affected substantially by the concentration, molecular weight, and degree of hydrolysis of PVA polymers used. There was evidence of increasing degrees of unfolding of the PVA polymer onto the poly(styrene) surface as the concentration of the the PVA coating solution increased. Complete PVA coverage of the poly(styrene) surface was observed at PVA concentrations of 0.1 mg/mL or greater but with significant influence of both molecular weight and degree of hydrolysis of the PVA polymers. Resistance of the PVA-coated poly(styrene) surface to the nonspecific adsorption of human serum albumin (HSA) correlated with the degree of surface coverage of the PVA. The use of anti-HSA as a probe for adsorbed HSA suggested that HSA was displacing PVA from the poly(styrene) surface at the lower PVA surface coverage. A complete barrier to nonspecific protein adsorption was observed with a PVA coating solution concentration of greater than 0.1 mg/ mL with a degree of hydrolysis of <88%.

Adsorption↗
PubMed2001

Calcium pyrophosphatase dihydrate (CPPD) crystal deposition disease in a teaching hospital in Kuwait.

OBJECTIVE: A Medline electronic search showed a paucity of reports on calcium pyrophosphate dihydrate crystal deposition disease (CPPD-CDD) from the Gulf region. To date only a single case report has been published from this region. Therefore, this study aimed, firstly, at finding out the prevalence of chondrocalcinosis in adult Arabs in Kuwait presenting with knee arthritis and, secondly, at carrying out an observational study of CPPD-CDD among Arabs in Kuwait. METHODS: For the study of the prevalence of chondrocalcinosis 100 consecutive adult patients presenting with knee arthritis were radiologically examined. For the observational study the clinical, laboratory, and radiological findings were analysed in patients with CPPD-CDD seen over a period of five years. RESULTS: This study showed the presence of chondrocalcinosis in two (2%) of the 100 adult Kuwaiti and other Middle-Eastern Arab patients (70 men, 30 women, median age 50 (range 45-80)) who presented to the rheumatology clinic for the evaluation of knee pain. When the younger age of the group (only three patients aged >70) is taken into account the figure was comparable with that reported from Western countries. Over a period of five years a total of 2726 new patients were evaluated at the rheumatology clinic of this institution. A diagnosis of crystal arthritis was made in 85 patients (3%). Fourteen of these 85 (that is, 16.5%, but 0.5% of the total cases) were diagnosed with definite (eight patients) or probable (six patients) CPPD-CDD. Different clinical presentations, including that of acute monarthritis (that is, pseudogout), premature generalised osteoarthritis, and polyarticular rheumatoid-like presentations, were seen in different patients. Overlap with true gout, with the additional presence of monosodium urate crystals in the joint aspirate, was seen in two patients. CONCLUSION: The present report shows that CPPD-CDD may not be uncommon among Arabs in the Gulf region. A high degree of clinical awareness and routine examination of joint aspirates with careful analysis for crystals may make it a more common diagnosis in this part of the world. In this regard it is interesting to note that cases and case series including familial cases have been reported from North Africa, especially Tunisia, indicating that the disease has been well described in Arabs of other geographical regions.

Adult↗
PubMed2001

Effect of oestrogen replacement therapy on bone mass in post-menopausal Bangladeshi women.

The female population comprises 48.66% of our total population, of which 10.30% are above the age of 49, many of whom are post-menopausal. Menopause is associated with bone-loss and its consequences. Hormone replacement therapy (HRT), particularly replacement of estrogen, prevents bone-loss. We undertook this prospective case-controlled study to find out whether or not HRT is beneficial to our women. A total of 106 patients were studied, amongst them 60 were cases and 46 were controls. The women in the first group were given either conjugated equine estrogen alone (surgical menopause group) or conjugated equine estrogen plus cyclical progesterone (natural menopause group). Results showed that there was 4.29% increase in bone mineral density in women who received hormone replacement therapy (HRT). This increase was 5.23% in early and 3.56% in late menopause group. Women with natural menopause gained more bone mass (4.22%) than women with surgical menopause (3.9%). Our results also showed that women who denied HRT (controls) lost bone mass (5.26%), the loss was more in those with surgical menopause (6.24%) than those with natural menopause (4.87%). Therefore it can be concluded that post-menopausal hormone replacement therapy prevents bone-loss. However, to evaluate the beneficial effect of long-term HRT, further studies with larger samples are recommended.

Bangladesh↗
PubMed2000

Glucagon-like peptide 1 increases glucose-dependent activity of the homeoprotein IDX-1 transactivating domain in pancreatic beta-cells.

Both glucose and glucagon-like peptide 1 (GLP-1) stimulate insulin gene transcription in endocrine pancreatic beta-cells within the islets of Langerhans. The effects of glucose are mediated by the homeodomain transcription factor islet duodenum homeobox -1 (IDX-1) that binds to two adenine thymidine-rich (A1 and A2/3) motifs within the rat insulin promoter. Glucose stimulates the activity of the transactivation domain of IDX-1 that lies within the first 80 amino acids of the IDX-1 protein. The effects of GLP-1 on insulin gene expression are primarily conferred by the cAMP responsive element (CRE) within the insulin promoter. GLP-1 stimulates glucose-dependent insulin release from beta-cells. We hypothesize that GLP-1 may augment the effects of glucose on insulin gene transcription. Here we show that GLP-1 stimulates insulin gene transcription independent of the CRE and is glucose-dependent. Furthermore, we show that GLP-1 stimulates the transactivational activity of IDX-1.

Animals↗
PubMed2000

Re-evaluation of anion-exchange HPLC for the analysis of acidic compounds.

A number of weak and strong anion-exchange HPLC phases have been evaluated for the analysis of acidic drugs and related compounds. Using eluents with high organic content, reasonable chromatography could be obtained and widely differing compounds easily separated in isocratic mode. Retention was related to solute pKa and concentration of ammonium acetate in the eluent. All the phases showed an unexplained loss in retention with repeated use, although with one material; nucleosil SAX, this was low (15%) and considered acceptable. This material was also shown to be relatively stable under typical bioanalytical conditions.

Acetates↗
PubMed2000

Consolidation behavior of an experimental, cross-linked polyalkyl ammonium polymer.

The effect of various factors (i.e., particle size, lubricant, moisture, and excipients) on the tableting properties of DMP 504 powder, an experimental, cross-linked polyalkyl ammonium polymer, was studied using an instrumented single-punch tablet press. The results indicate that plastic deformation is the primary consolidation mechanism for DMP 504. Lubrication of DMP 504 with magnesium stearate resulted in negative interaction in compactibility. The increase in tablet hardness with increase in water content of DMP 504 (up to 2.5%) could be attributed to the lubricating effect of water. Increasing the water content above the optimum moisture range (i.e., 2.5% to 4.0%) caused a drastic reduction in tablet crushing strength due to the hydrodynamic resistance. A mixture of DMP 504 with microcrystalline cellulose or starch led to a positive interaction with respect to compactibility. A deviation in tablet strength from the linear interpolated value did not correspond to a deviation in tablet thickness. The improved compactibility for the mixture of DMP 504 and microcrystalline cellulose or starch is not related directly to the facilitated densification.

Chemistry, Pharmaceutical↗
PubMed2000

Glucagon stimulates expression of the inducible cAMP early repressor and suppresses insulin gene expression in pancreatic beta-cells.

The hormone glucagon is secreted by the alpha-cells of the endocrine pancreas (islets of Langerhans) during fasting and is essential for the maintenance of blood glucose levels by stimulation of hepatic glucose output. Excessive production and secretion of glucagon by the alpha-cells of the islets is a common accompaniment to diabetes. The resulting hyperglucagonemia stimulates hepatic glucose production, thereby contributing to hyperglycemia of diabetes. The reduced insulin secretion in diabetes and resultant failure to suppress glucagon secretion by intra-islet paracrine mechanisms is believed to cause the hypersecretion of glucagon. Here, we report the discovery of a new mechanism by which glucagon suppresses insulin secretion. We show that glucagon, but not glucagon-like peptide 1 (GLP-1), or pituitary adenylyl cyclase-activating peptide (PACAP) specifically induces the expression of the transcriptional repressor inducible cAMP early repressor (ICER) in pancreatic beta-cells, resulting in a repression of the transcriptional expression of the insulin gene. Remarkably, glucagon, GLP-1, and PACAP all stimulate the formation of cAMP to a comparable extent in rat pancreatic islets, but only glucagon activates the expression of ICER and represses insulin gene transcription in beta-cells. These findings lead us to propose that hyperglucagonemia may additionally aggravate the diabetic phenotype via a suppression of insulin gene expression mediated by the transcriptional repressor ICER.

1-Methyl-3-isobutylxanthine↗