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N Ahmed

Publications and source records attributed to N Ahmed.

At least 19 recordsLinked to original sources
PubMed2006

Translational proteomics: developing a predictive capacity -- a review.

Over the past decade, proteomics has undergone a rapid development and radiation, diversifying across the biochemical landscape. While no single technique yet delivers complete proteomic coverage, application-specific adaptations afford significant opportunity for discovery and the development of predictive capacity (e.g. surrogate biomarker and clinical diagnostics). Targeted proteomic approaches, protein profiling strategies using affinity capture mass spectrometry and solution array represent realistic opportunities to deliver predictive capacity. The aim of this review is to provide an overview of proteomic technologies and how the outcomes delivered by such platforms may be translated into applications of predictive utility in clinical and basic science. In particular, recent applications in protein/peptide profiling (solid-phase affinity capture mass spectrometry and the targeted approach of antibody arrays) and the opportunities they afford researchers within the discipline of reproductive biology to develop new diagnostic and prognostic tests and surrogate biomarkers to improve the delivery of women's health care are considered.

Animals↗
PubMed2006

A novel missense mutation of SLC7A9 frequent in Japanese cystinuria cases affecting the C-terminus of the transporter.

Cystinuria is caused by the inherited defect of apical membrane transport systems for cystine and dibasic amino acids in renal proximal tubules. Mutations in either SLC7A9 or SLC3A1 gene result in cystinuria. The mutations of SLC7A9 gene have been identified mainly from Italian, Libyan Jewish, North American, and Spanish patients. In the present study, we have analyzed cystinuria cases from oriental population (mostly Japanese). Mutation analyses of SLC7A9 and SLC3A1 genes were performed on 41 cystinuria patients. The uptake of 14C-labeled cystine in COS-7 cells was measured to determine the functional properties of mutants. The protein expression and localization were examined by Western blot and confocal laser-scanning microscopy. Among 41 patients analyzed, 35 were found to possess mutations in SLC7A9. The most frequent one was a novel missense mutation P482L that affects a residue near the C-terminus end of the protein and causes severe loss of function. In MDCK II and HEK293 cells, we found that P482L protein was expressed and sorted to the plasma membrane as well as wild type. The alteration of Pro482 with amino acids with bulky side chains reduced the transport function of b(0,+)AT/BAT1. Interestingly, the mutations of SLC7A9 for Japanese cystinuria patients are different from those reported for European and American population. The results of the present study contribute toward understanding the distribution and frequency of cystinuria-related mutations of SLC7A9.

Amino Acid Substitution↗
PubMed2006

Estimates of dietary exposure of children to artificial food colours in Kuwait.

To assess the intake of artificial food colour additives by 5-14-year-old children in the State of Kuwait, a 24-h dietary recall was conducted twice on 3141 male and female Kuwaiti and non-Kuwaiti children from 58 schools. The determination of colour additives in 344 foods items consumed was performed using high-performance liquid chromatography with diode array detector. A comparison with the Food and Agriculture Organization and World Health Organization acceptable daily intakes (ADIs) was undertaken to evaluate the potential risk associated with the consumption of artificial colour additives by children in Kuwait. The results indicated that out of nine permitted colours, four exceeded their ADIs by factors of 2-8: tartrazine, sunset yellow, carmoisine and allura red. Further, follow-up studies to provide insight into potential adverse health effects associated with the high intakes of these artificial colour additives on the test population are warranted.

Adolescent↗
PubMed2006

Spot morning urine protein creatinine ratio and 24 hour urinary total protein excretion rate.

Proteinuria helps to establish the diagnosis of most renal diseases and also to predict the outcome of such diseases. Proteinuria is biochemically represented by measuring the protein concentration in timed collection of 24 hour urine. But, 24-hour timed urine collection is time consuming, cumbersome and often unreliable due to collection errors and also results in undue delay on diagnostic process. An alternate approach avoiding arduous and inaccurate timed urine collection can be the measurement of protein creatinine ratio in spot morning urine. This study was aimed to evaluate whether the spot morning urine protein creatinine ratio can be a reliable alternative to 24-hour urinary total protein (UTP) estimation. The study was carried out in the department of Biochemistry, Bangabandhu Sheikh Mujib Medical University, Dhaka on 50 (fifty) non-diabetic Chronic Renal Disease (CRD) patients with an age ranging from 18 -70 years. The study subjects were grouped into mild, moderate and severe CRD on the basis of GFR. Urinary protein and creatinine concentrations were measured in spot morning urine samples and their ratios were calculated. Urinary protein measured in 24-hour timed collected urine samples gave the 24-hour UTP excretion rate. In our study, spot morning urine protein creatinine ratio significantly correlated with 24-hour UTP excretion rate in all CRD patients. Severe CRD patients gave significant positive correlation (p<0.05), whereas mild and moderate CRD patients gave very highly significant positive correlation (p<0.001). Therefore, it may be suggested that protein creatinine ratio in spot morning urine can be accepted as a reliable and alternative to 24-hour UTP excretion rate in non-diabetic chronic renal disease patients. This simple and inexpensive procedure will thus simplify the way of establishing the severity of renal disease along with its prognosis.

Adolescent↗
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

Diagnostic MR imaging features of craniocerebral Aspergillosis of sino-nasal origin in immunocompetent patients.

BACKGROUND: Craniocerebral invasive Aspergillosis of sino-nasal origin has been reported with a very high mortality due to a peculiarly fulminant clinical course. Early diagnosis based on clinical radiological imaging may have an impact on final clinical outcome. This retrospective study focuses on characteristic MR imaging features of Aspergillosis (of sinonasal origin) in immunocompetent patients. METHODS: Medical records of patients were reviewed retrospectively during the period from 1991 to 2003 in the two tertiary care hospitals. All the patients had radiological evidence of disease in the paranasal sinuses with or without intracranial extension. Immunocompetence of patients was assessed on clinical and radiological data. MRI scans (n=20) were reviewed by both clinical neurosurgeons and neuroradiologists separately. MRI was done on 1.5 tesla scanners and both T2-weighted and T1 weighted sequences were obtained followed gadolinium enhanced images. Patients were categorized into three types based on their anatomical location on MRI scans; type-1 being intracerebral, type-2 as intracranial extradural and type-3 invading orbit and/or skull base only. All these patient had the epicenter of disease in the nose and/or paranasal sinuses as evident on MR imaging. All patients underwent standard surgical intervention followed by antifungal therapy. Clinical outcome was assessed on Glasgow outcome scale with mean duration of clinical follow up of 13.9 months. FINDINGS: Mean age of patents (n=20) was 31.1 years with male preponderance (3:1). MRI scans showed evidence of disease in paranasal sinuses including mucosal thickening (n=11) and complete filling of sinuses (n=9). T2-weighted images showed extremely hypo-intense fungal mass (n=19) while T1-weighted images had iso-intense signals (n=18). Gadolinium-enhanced images showed bright homogenous contrast enhancement (n=18) and peripheral ring enhancement pattern (n=2). All patients underwent appropriated surgical procedures depending upon anatomical location followed by standard antifungal therapy. Tissue diagnoses were established by histopathology (n=20) and culture growth (n=5). Overall mortality remained 15 percent. INTERPRETATION: Craniocerebral Aspergillosis of sinonasal origin has typical MR imaging features. These features include a mass lesion producing hypo-to-iso-intense signals on T1-weighted, extremely low signals (hypo-intense) on T2-weighted images, with bright homogenous enhancement on post-gadolinium T1-weighted imaging. These features in the clinical background may be helpful in early diagnosis and management of Aspergillosis of sino-nasal origin in immunocompetent hosts. Prospective clinical study is required to make firm clinical therapeutic recommendations.

Adolescent↗
PubMed2005

Isolation and characterization of heparin and gelatin binding buffalo seminal plasma proteins and their effect on cauda epididymal spermatozoa.

Seventy semen ejaculates were obtained from 14 Murrah buffalo bulls and were subjected to plasma separation immediately after collection by centrifugation at 2000 rpm for 20 min and stored in liquid nitrogen until analysis. In the seminal plasma the total protein concentration were estimated and the heparin and gelatin binding (HB and GB) proteins were isolated using heparin and gelatin affinity column chromatography. The molecular weight of individual isolated HB and GB protein was determined by SDS-PAGE analysis. Buffalo bull spermatozoa was collected from cauda epididymis under aseptic conditions and was used for the in vitro fertility tests (i.e. bovine cervical mucus penetration test (BCMPT) and hypo-osmotic swelling test (HOST)). The heparin and gelatin binding buffalo seminal plasma proteins were used in six concentrations i.e. 10, 20, 30, 40, 50 and 60 microg/ml to test their effect on in vitro fertility assessment of cauda epididymal spermatozoa. The overall mean values of total protein, HB and GB proteins were recorded as 29+/-2.7, 2.61 and 0.2mg/ml, respectively. Eighteen total protein bands were observed in the range of 12-127 kDa. Eight major HB proteins were isolated in the range of 13-71 kDa. Seven major GB proteins were isolated in the range of 13-61 kDa in the buffalo seminal plasma. The mean penetration distance (mm) travelled by the buffalo cauda spermatozoa was maximum in HB proteins (26.9+/-0.6) followed by GB proteins (25.4+/-0.6) and control (21.2+/-1.4). The difference in BCMPT values between protein treated and control group was significant (P<0.05). Almost similar trend in the effect of protein on values of HOST percentage in both HB and GB proteins treated semen samples were recorded (66.4+/-0.65 and 66.1+/-0.6, respectively). The difference in HOST values between proteins treated and control group (50.4+/-2.0) was significant (P<0.05). The present results indicate that among the isolated proteins, 4 proteins were commonly seen in both the heparin and gelatin-sepharose affinity column chromatography, and the addition of buffalo seminal plasma proteins improved the in vitro sperm functions (40 microg/ml gave best results) of buffalo cauda spermatozoa.

Animals↗
PubMed2005

Immunization with DNA vaccines encoding different mycobacterial antigens elicits a Th1 type immune response in lambs and protects against Mycobacterium avium subspecies paratuberculosis infection.

Paratuberculosis, or Johne's disease, is a disease of domestic and wild ruminants that culminate with a chronic enteritis caused by Mycobacterium avium subsp. paratuberculosis. The aim of this work was to evaluate the type of immune response, Th1 or Th2, induced by DNA vaccinations in lambs of Sarda breed. Twenty-five lambs, serum negative for M. paratuberculosis, were selected at birth from equally serum negative mothers. The lambs were inoculated at 5 months of age with three different mycobacterial antigens cloned into a mammalian expression vector as fusion protein with the enhanced green fluorescent protein (pEGFP-N1). The animals were divided in five groups containing each five lambs. Each group was vaccinated as following (A: physiological solution; B: Gudair; C: p-85A-Mav; D: p-85A-BCG; E: p-Hsp65). Immune response was evaluated by measuring the expression of INF-gamma (Th1 type response) and IL-10 (Th2 type response) by real-time PCR. Gene expression was estimated by comparing the results with that of beta-actin. INF-gamma expression level was increased in lambs vaccinated with plasmids codifying mycobacterial antigens, in particular with p-Hsp65, in comparison with the controls suggesting stimulation of a Th1 immune response similar to that supported by natural infection of M. paratuberculosis. Moreover, animals were infected orally with live M. paratuberculosis. Three months after vaccination and again INF-gamma and IL-10 expression was evaluated in order to verify in vivo the protection level of the vaccines. Plasmids p-85A-BCG and p-Hsp65 seem to elicit a stronger protective immune response against M. paratuberculosis by evaluating the expression level of INF-gamma and evaluating the presence of M. paratuberculosis and animal cell organ damage post-mortem.

Animals↗
PubMed2005

Degradation products of proteins damaged by glycation, oxidation and nitration in clinical type 1 diabetes.

AIMS/HYPOTHESIS: Hyperglycaemia in diabetes is associated with increased glycation, oxidative stress and nitrosative stress. Proteins modified consequently contain glycation, oxidation and nitration adduct residues, and undergo cellular proteolysis with release of corresponding free adducts. These free adducts leak into blood plasma for eventual renal excretion. The aim of this study was to perform a comprehensive quantitative analysis of protein glycation, oxidation and nitration adduct residues in plasma protein and haemoglobin as well as of free adducts in plasma and urine to quantify increased protein damage and flux of proteolytic degradation products in diabetes. METHODS: Type 1 diabetic patients (n=21) and normal healthy control subjects (n=12) were studied. Venous blood samples, with heparin anticoagulant, and 24-h urine samples were taken. Samples were analysed for protein glycation, oxidation and nitration adducts by a quantitative comprehensive screening method using liquid chromatography with triple quadrupole mass spectrometric detection. RESULTS: In type 1 diabetic patients, the concentrations of protein glycation, oxidation and nitration adduct residues increased up to three-fold in plasma protein and up to one-fold in haemoglobin, except for decreases in pentosidine and 3-nitrotyrosine residues in haemoglobin when compared with normal control subjects. In contrast, the concentrations of protein glycation and oxidation free adducts increased up to ten-fold in blood plasma, and urinary excretion increased up to 15-fold in diabetic patients. CONCLUSIONS/INTERPRETATION: We conclude that there are profound increases in proteolytic products of glycated and oxidised proteins in diabetic patients, concurrent with much lower increases in protein glycation and oxidation adduct residues.

Adult↗
PubMed2005

Quantitative determination of organochlorine pesticides in sewage sludges using soxtec, soxhlet and pressurized liquid extractions and ion trap mass-mass spectrometric detection.

A new analytical method is described for the determination of organochlorine pesticides (OCPs) in sewage sludges using GC-ion trap-MS-MS. In this work, 16 organo-chlorine pesticides (OCPs) listed by the US Environmental Protection Agency (US EPA) as priority pollutants were separated and quantified. Sludge samples from three of Kuwait's wastewater treatment plants (WWTPs) were analyzed for organochlorine pesticides (OCPs). Spiked sludge samples were extracted with a mixture of (1:1 v/v) dichloromethane (DCM)/hexane. The extracts were cleaned on a silica/aluminum oxide column, then transferred to a gel permeation chromatography (GPC) column, before undergoing further silica/aluminum oxide clean-up; the presence of OCPs was then confirmed by GC-ion trap-MS-MS. Three extraction techniques, soxtec, soxhlet, and pressurized liquid extractions were utilized, compared and validated using the spiked sludge samples. The methods were validated in term of accuracy (recovery) and precision (RSD). The method recovery values varied from 76.1 to 92.9% for the three extraction techniques.

Aluminum Oxide↗
PubMed2005

Ascites induces modulation of alpha6beta1 integrin and urokinase plasminogen activator receptor expression and associated functions in ovarian carcinoma.

Interactions between cancer cells and the surrounding medium are not fully understood. In this study, we demonstrate that ascites induces selective changes in the expression of integrins and urokinase plasminogen activator/urokinase plasminogen activator receptor (uPA/uPAR) in ovarian cancer cells. We hypothesise that this change of integrin and uPA/uPAR expression triggers signalling pathways responsible for modulating phenotype-dependent functional changes in ovarian cancer cells. Human ovarian surface epithelial (HOSE) cell lines and epithelial ovarian cancer cell lines were treated with ascites for 48 h. Ascites induced upregulation of alpha6 integrin, without any change in the expression of alphav, beta1 and beta4 integrin subunits. Out of the four ovarian cancer cell lines studied, ascites induced enhancement in the expression of uPA/uPAR in the more invasive OVCA 433 and HEY cell lines without any change in the noninvasive OVHS1 and moderately invasive PEO.36 cell lines. On the other hand, no change in the expression of alpha6 integrin or uPAR, in response to ascites, was observed in HOSE cells. In response to ascites, enhancement in proliferation and in adhesion was observed in all four ovarian cancer cell lines studied. In contrast, no significant increase in proliferation or adhesion by ascites was observed in HOSE cells. Ascites-induced expression of uPA/uPAR correlated with the increased invasiveness of HEY and OVCA 433 cell lines but was not seen in OVHS1, PEO.36 and HOSE cell lines. Upregulation of alpha6 integrin and uPA/uPAR correlated with the activation of Ras and downstream Erk pathways. Ascites-induced activation of Ras and downstream Erk can be inhibited by using inhibitory antibodies against alpha6 and beta1 integrin and uPAR, consistent with the inhibition of proliferation, adhesion and invasive functions of ovarian cancer cell lines. Based on these findings, we conclude that ascites can induce selective upregulation of integrin and uPA/uPAR in ovarian cancer cells and these changes may modulate the functions of ovarian carcinomas.

Ascites↗
PubMed2005

Enhanced expression of peroxisome proliferator-activated receptor gamma in epithelial ovarian carcinoma.

The peroxisome proliferator-activated receptors (PPARs) belong to a subclass of nuclear hormone receptor that executes important cellular transcriptional functions. Previous studies have demonstrated the expression of PPARgamma in several tumours including colon, breast, bladder, prostate, lung and stomach. This study demonstrates the relative expression of PPARgamma in normal ovaries and different pathological grades of ovarian tumours of serous, mucinous, endometrioid, clear cell and mixed subtypes. A total of 56 ovarian specimens including 10 normal, eight benign, 10 borderline, seven grade 1, nine grade 2 and 12 grade 3 were analysed using immunohistochemistry. Immunoreactive PPARgamma was not expressed in normal ovaries. Out of eight benign and 10 borderline tumours, only one tumour in each group showed weak cytoplasmic PPARgamma expression. In contrast, 26 out of 28 carcinomas studied were positive for PPARgamma expression with staining confined to cytoplasmic and nuclear regions. An altered staining pattern of PPARgamma was observed in high-grade ovarian tumours with PPARgamma being mostly localized in the nuclei with little cytoplasmic immunoreactivity. On the other hand, predominant cytoplasmic staining was observed in lower-grade tumours. Significantly increased PPARgamma immunoreactivity was observed in malignant ovarian tumours (grade 1, 2 and 3) compared to benign and borderline tumours (chi2 = 48.80, P < 0.001). Western blot analyses showed significant elevation in the expression of immunoreactive PPARgamma in grade 3 ovarian tumours compared with that of normal ovaries and benign ovarian tumours (P < 0.01). These findings suggest an involvement of PPARgamma in the onset and development of ovarian carcinoma and provide an insight into the regulation of this molecule in the progression of the disease.

Adenocarcinoma, Clear Cell↗
PubMed2005

Advanced glycation end product free adducts are cleared by dialysis.

Plasma advanced glycation end product (AGE) free adducts are increased up to 50-fold among patients on dialysis. We examined the ability of hemodialysis (HD) and continuous ambulatory peritoneal dialysis (CAPD) to clear these compounds. The AGE free adducts Nepsilon-carboxymethyl-lysine (CML) and Nepsilon-(1-carboxyethyl)lysine (CEL) and the hydroimidazolones derived from glyoxal (G-H1), methylglyoxal (MG-H1), and 3-deoxyglucosone (3DG-H) were determined by LC-MS/MS and pentosidine by HPLC with fluorimetric detection in ultrafiltrates of plasma, urine, or PD effluent as appropriate from patients on HD (n = 8) or PD (n = 8), and from healthy controls (n = 8). Among patients on HD, all free AGEs predialysis were significantly higher than in controls and were decreased with dialysis. The removal of MG-H1 and 3DG-H was comparable to that of urea, whereas that of CML and pentosidine was some 20% higher; in contrast, the removal of CEL and G-H1 was 25% lower. Among patients on CAPD, free AGEs in PD effluent increased with increasing dwell time. The combined renal and peritoneal 24-h excretion rates of CML (4.7 micromol), CEL (6.5 micromol), 3DG-H (16.6 micromol), and pentosidine (0.08 micromol) were twofold higher than the amount excreted in healthy controls, whereas MG-H1 was ninefold higher (59 micromol); the combined clearances of all free AGEs except pentosidine were lower than in healthy controls. Impaired renal clearance contributes to increased plasma free AGEs in uremia, but the increased excretion rate among patients on PD demonstrates that there was also an increased synthesis of free AGEs. Both HD and PD are able to remove free AGEs.

Adult↗
PubMed2005

A comparative study on effect of lamivudine in wild and precore mutant variety of chronic hepatitis B virus infected patients.

The aim of this study is to evaluate the effectiveness of lamivudine treatment in both precore mutant and wild type of chronic hepatitis B (CHB) patients. The study was done on sixty CHB patients of both sexes seeking treatment in the Outpatient Department and admitted patients of Mymensingh Medical College Hospital. The patients were divided into two groups. Group A included chronic hepatitis B patients with raised ALT (> 80 u/l ) with HBeAg positivity, and group B included precore mutant variety of CHB patients with raised ALT (> 80 u/l) with HBeAg negativity. In Group-A, after 1 year of completion of lamivudine therapy there was 86.67% normalization of ALT, 23.33% HBeAg loss, 16.67% anti-HBeAg development and 73.33% HBV DNA loss. In Group-B, there was 76.67% normalization of ALT and 73.33% HBV DNA loss after 1 year of completion of therapy. In the present study, it was observed that lamivudine is equally effective in both wild and precore mutant variety of CHB patients. This was reflected by normalization of ALT and loss of HBV DNA. This study also shows the reappearance of HBV DNA during the later half of Lamivudine therapy which is due to YMDD mutation.

Antiviral Agents↗