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Biomedical subjects

A Ahmad

Publications and source records attributed to A Ahmad.

At least 19 recordsLinked to original sources
PubMed2006

Exaggerated vasomotor response to ANG II in rats with fetal programming of hypertension associated with exposure to a low-protein diet during gestation.

The renin-angiotensin system plays a key role in the initiation and maintenance of elevated blood pressure associated with altered intrauterine milieu. The current studies were undertaken to verify whether vascular response to ANG II is increased in adult offspring of low-protein fed dams (LP) compared with control (CTRL) and if so, to examine underlying mechanism(s). ANG II-induced contraction of carotid rings was increased in LP (E(max), the maximum asymptote of the curve, relative to maximal response to KCl 80 mM: 230 +/- 3% LP vs. 201 +/- 2% CTRL, P < 0.05). In both groups, contraction to ANG II was mediated solely by AT1R. Responses to thromboxane A2 analog U-46619 and to KCl 80 mM under step increases in tension were similar between groups. Endothelium depletion enhanced contraction to ANG II in both groups, more so in LP. Blockade of endothelin formation had no effect on response to ANG II, and ANG-(1-7) did not elicit vasomotor response in either group. Superoxide dismutase (SOD) analog Tempol normalized LP without modifying CTRL response to ANG II. Basal levels of superoxide (aortic segments, lucigenin-enhanced chemiluminescence and fluorescent dye hydroethidine) were higher in LP. ANG II further increased superoxide production in LP only, and this was inhibited by coincubation with diphenylene iodonium or apocynin (inhibitor of NADPH oxidase complex). AT1R expression in carotid arteries was increased in LP, whereas SOD expression was unchanged. In conclusion, vasoconstriction to ANG II is exaggerated in this model of developmental programming of hypertension, secondary to enhanced vascular production of superoxide anion by NADPH oxidase with concomitant increase of AT1R expression.

Age Factors↗
PubMed2006

Brillouin-Raman comb fiber laser with cooperative Rayleigh scattering in a linear cavity.

We demonstrate a multiple-wavelength Brillouin comb laser with cooperative Rayleigh scattering that uses Raman amplification in dispersion-compensating fiber. The laser resonator is a linear cavity formed by reflector at each end of the dispersion-compensating fiber to improve the reflectivity of the Brillouin Stokes comb. Multiple Brillouin Stokes generation has been improved in terms of optical signal-to-noise ratio and power-level fluctuation between neighboring channels. Furthermore, the linewidth of the Brillouin Stokes is uniform within the laser output bandwidth.

Journal Article↗
PubMed2006

Current chronic kidney disease practice patterns in the UK: a national survey.

BACKGROUND: There is an increasing focus on improving the detection and management of patients with chronic kidney disease (CKD). Data on CKD prevalence based on population sampling are now available, but there are few data about CKD patients attending nephrology services or how such services are organized. AIM: To survey services for CKD patients nationally. METHODS: A pre-piloted questionnaire was sent to all 72 renal units in the UK, referring to the situation in June 2004. RESULTS: Seventy units (97%) responded. The median ratio of prevalent CKD patients/prevalent renal replacement therapy (RRT) patients in the 25 units with data was 3.7 (IQR 2.7-5.7) and the median ratio of CKD stage 4 and 5 patients/prevalent RRT patients was 0.6 (IQR 0.4-1.1). This gives an estimated 140 000 CKD patients under the care of UK nephrologists, with 23 000 at CKD stage 4 or 5 (excluding those on RRT). Very few units had a full complement of the recommended multi-skilled renal team. Counsellors and psychologist were the most common perceived shortages. Of 70 responding units, 50 (74%) were using low clearance clinics for management of advanced CKD patients. Elective dialysis access services often had long delays, with median waiting time for vascular access ranging between 1 and 36 weeks, and for Tenchkoff catheter, between 0 and 12 weeks. DISCUSSION: CKD patients are a significant workload for UK nephrologists. Current provision of service is variable, and services need to be re-designed to cope with the expected future increase of referral of CKD patients.

Chronic Disease↗
PubMed2006

Optimization of nitrogen and phosphorus limitation for better biodegradable plastic production and organic removal using single fed-batch mixed cultures and renewable resources.

The process for the production of biodegradable plastic material (polyhydroxyalkanoates, PHAs) from microbial cells by mixed-bacterial cultivation using readily available waste (renewable resources) is the main consideration nowadays. These observations have shown impressive results typically under high carbon fraction, COD/N and COD/P (usually described as nutrient-limiting conditions) and warmest temperature (moderate condition). Therefore, the aim of this work is predominantly to select mixed cultures under high storage responded by cultivation on a substrate - non limited in a single batch reactor with shortest period for feeding and to characterize their storage response by using specific and kinetics determination. In that case, the selected-fixed temperature is 30 degrees C to establish tropical conditions. During the accumulated steady-state period, the cell growth was inhibited by high PHA content within the cells because of the carbon reserve consumption. From the experiments, there is no doubt about the PHA accumulation even at high carbon fraction ratio. Apparently, the best accumulation occurred at carbon fraction, 160 +/- 7.97 g COD/g N (PHAmean, = 44.54% of dried cells). Unfortunately, the highest PHA productivity was achieved at the high carbon fraction, 560 +/- 1.62 g COD/g N (0.152 +/- 0.17 g/l. min). Overall results showed that with high carbon fraction induced to the cultivation, the PO4 and NO3 can remove up to 20% in single cultivation.

Biodegradation, Environmental↗
PubMed2006

[Left-sided appendicitis: description of a rare case in an adult patient diagnosed in Antananarivo].

The purpose of this report is to describe a case of appendicitis in the left iliac fossa. Clinical presentation involved pain in the right iliac fossa with all classical signs of appendicitis. Anomalous location of the appendix was suspected on the basis of a special clinical feature and the patient's family history. Confirmation was achieved by colic contrast enema before surgical treatment.

Abdominal Pain↗
PubMed2005

SHO pay scales.

Explore the source record for details and available documents.

Dentists↗
PubMed2005

Tyrosinase inhibitory lignans from the methanol extract of the roots of Vitex negundo Linn. and their structure-activity relationship.

Phytochemical investigation of the methanol extract of Vitex negundo afforded eight lignans; negundin A 1, negundin B 2, 6-hydroxy-4-(4-hydroxy-3-methoxy)-3-hydroxymethyl-7-methoxy-3,4-dihydro-2-naphthaledehyde 3, vitrofolal E 4, (+)-lyoniresinol 5, (+)-lyoniresinol-3alpha-O-beta-d-glucoside 6, (+)-(-)-pinoresinol 7, and (+)-diasyringaresinol 8. The structures of these compounds were elucidated unambiguously by spectroscopic methods including 1D and 2D NMR analysis and also by comparing experimental data with literature data. The tyrosinase inhibitory potency of these compounds has been evaluated and attempts to justify their structure-activity relationships have been made in the present work. The compound 5 was found to be the most potent (IC(50)=3.21 microM) while other compounds demonstrated moderate to potent inhibitions. It was found that the substitution of functional group(s) at C-2 and C-3 positions and the presence of the -CH(2)OH group plays a vital role in the potency of the compounds. The compound 5 can act as a potential lead molecule to develop new drugs for the treatment of hyperpigmentation associated with the high production of melanocytes.

Inhibitory Concentration 50↗
PubMed2005

Extra-cranial metastasis of glioblastoma multiforme presenting as acute parotitis.

We present an unusual case of extracranial metastasis of glioblastoma multiforme (GBM) to the parotid gland and cervical lymph nodes. The patient had previously undergone two craniotomies to debulk a left frontal GBM, followed by radiotherapy. After the second craniotomy, while waiting for chemotherapy, the patient was re-admitted with a short history of a painful swelling of his left parotid gland. The initial diagnosis was infective parotitis; however, as there was no improvement with broad-spectrum antibiotics, CT was undertaken, which revealed a mass in the parotid gland with a necrotic centre and enlarged cervical lymph nodes. Parotid gland biopsy revealed a parotid GBM metastasis. This case illustrates how GBM behaves in an aggressive manner even outside the CNS. A brief review of the literature and of the theories, which might explain the extra-neural metastasis of this tumour is also presented.

Acute Disease↗
PubMed2005

Trends in adult renal replacement therapy in the UK: 1982-2002.

BACKGROUND: Following the introduction of dialysis and transplantation for the treatment of established renal failure (ERF) 40 years ago, the UK failed to match the achievements of many other countries. AIM: To review progress with treatment for ERF in the UK in the past 20 years. DESIGN: Review of four cross-sectional national studies, and 1997-2002 annual UK Renal Registry data. METHODS: Data on UK patients on renal replacement treatment (RRT) were collated from three sources: European Registry reports for 1982-1990, surveys carried out within the UK in 1993, 1996, 1998 and 2002, and the UK Renal Registry database (1997-2002). Trends in acceptance and prevalence rates, median age, cause of ERF, and treatment modality were analysed and compared with current data from other countries. RESULTS: The UK annual acceptance rate for RRT increased from 20 per million population (pmp) in 1982 to 101 pmp in 2002. This growth was largely in those aged over 65 years, and in those with co-morbidity. Annual acceptance rates for ERF due to diabetes rose from 1.6 to 18 pmp. The prevalence of RRT increased from 157 pmp in 1982 to 626 pmp in 2002. Hospital haemodialysis has become the main modality, and is increasingly being provided in satellite units. Although rising, UK acceptance and prevalence rates are still lower than in many developed countries. DISCUSSION: Despite significant expansion in RRT services for adults in the UK over the last 20 years, there is evidence of unmet need, and need is expected to rise, due to demographic changes and trends in type 2 diabetes. Continuing growth in the already substantial investment in RRT will be needed, unless efforts to prevent the occurrence of ERF are successful.

Adolescent↗
PubMed2005

A 2-year follow-up of orphans' competence, socioemotional problems and post-traumatic stress symptoms in traditional foster care and orphanages in Iraqi Kurdistan.

BACKGROUND: This paper aims to compare orphans' development in two different care systems. METHODS: Based on age, sex, psychological trauma scores, competence and psychological problem scores, two comparable samples were found representing orphans in the traditional foster care (n = 94) and the orphanages (n = 48) in a middle-large city in Iraqi Kurdistan. At an index interview, Child Behaviour Checklist (CBCL), Harvard-Uppsala Trauma Questionnaire for Children and Post-traumatic Stress Symptoms for Children (PTSS-C) were administered to the caregivers. After 1 year the CBCL, and after 2 years both the CBCL and the PTSS-C, were-re-administered, consecutively. RESULTS: Although both samples revealed significant decrease in the means of total competence and problem scores over time, the improvement in activity scale, externalizing problem scores and post-traumatic stress disorder-related symptoms proved to be more significant in the foster care than in the orphanages. While the activity scale improved in the foster care, the school competence deteriorated in both samples, particularly among the girls in the orphanages. The improvement of boys' activity scores in the foster care, and deterioration of girls' school competence in the orphanages were the most significant gender differences between samples over time. CONCLUSIONS: Even if the two orphan care systems showed more similarities than differences, the foster care revealed better outcomes over time. The results are discussed in relation to gender, age, socio-economic situation, cultural values and the characteristics of each care system.

Adolescent↗
PubMed2005

Medical interns knowledge of TB in Pakistan.

Of 460 interns from five Pakistani teaching hospitals surveyed, only 22% correctly identified the estimated number of new TB cases in Pakistan. The majority (96%) knew that droplet infection was the usual mode of transmission. Only 38% considered sputum smears for acid-fast bacilli as the best test for diagnosis of pulmonary TB and 43.5% for follow-up during TB treatment. The recommended four-drug anti-TB regimen was prescribed by 56.5% in the initiation phase and the recommended two-drug combination in the continuation phase by 52%. Most interns (82%) were unable to identify a single component of directly observed treatment short course (DOTS) strategy. Our study reflects poor awareness of and low compliance to the World Health Organization/National Tuberculosis Programme guidelines among interns. For effective control of TB, immediate action to improve undergraduate and continuing medical education is essential, with special emphasis on national guidelines.

Clinical Competence↗
PubMed2004

Restorative potential of dopaminergic grafts in presence of antioxidants in rat model of Parkinson's disease.

Free radical mediated damage has been reported to contribute significantly towards low survival (5-10%) of grafted dopaminergic neurons, post transplantation. In the present study, an attempt has been made to explore the neuroprotective potential of the combination of two major antioxidants ascorbic acid (AA) and glutathione (GSH) on ventral mesencephalic cells (VMC) and nigral dopamine (DA) neurons when co-transplanted together with VMC in rat model of Parkinson's disease (PD). GSH and AA have been reported to act co-operatively in the conditions of oxidative stress thereby helping in maintaining the cellular GSH/GSSG redox status. Functional recovery was assessed 12 weeks post transplantation, where a significant restoration (p<0.001) in d-amphetamine induced circling behavior (62%), spontaneous locomotor activity (SLA; 64%), dopamine-D2 receptor binding (63%), dopamine (65%) and 3,4-dihydroxy phenyl acetic acid (DOPAC) level (64%) was observed in co-transplanted animals as compared to lesioned and VMC alone grafted rats. VMC and GSH+AA co-transplanted animals exhibited a significantly higher surviving TH-immunoreactive (TH-ir) neurons number (p<0.01), TH-ir fibers outgrowth (p<0.05) in striatal graft and TH-ir neurons in substantia nigra pars compacta (SNpc) (p<0.01), as compared to VMC alone transplanted rats. An attempt was made to further confirm our in vivo observations through in vitro experiments where following in vitro exposure to 6-OHDA, a higher cell survival (p<0.01), TH-ir cell counts (p<0.001) and DA and DOPAC levels (p<0.01) were also observed in 8-day-old VMC culture in presence of GSH+AA as compared to VMC cultured in absence of antioxidants. The results suggest that GSH+AA when co-transplanted with VMC provide higher restoration probably by increasing the survival of grafted VMC and simultaneously supporting nigral TH-immunopositive neurons in rat model of PD.

3,4-Dihydroxyphenylacetic Acid↗
PubMed2004

Olfactory ensheathing cell transplantation restores functional deficits in rat model of Parkinson's disease: a cotransplantation approach with fetal ventral mesencephalic cells.

Different strategies have been worked out to promote survival of transplanted fetal ventral mesencephalic cells (VMCs) using trophic and nontrophic support. Olfactory ensheathing cells (OECs) express high level of growth factors including NGF, bFGF, GDNF, and NT3, which are known to play important role in functional restoration or neurodegeneration. In the present investigation, an attempt has been made to study functional restoration in 6-hydroxydopamine (6-OHDA)-lesioned rat model of Parkinson's disease (PD) following cotransplantation of VMC and OECs (cultured from olfactory bulb, OB) in striatal region. The functional restoration was assessed using neurobehavioral, neurochemical, and immunohistochemical approach. At 12 weeks, post-transplantation, a significant recovery (P < 0.001) in D-amphetamine induced circling behavior (73%), and spontaneous locomotor activity (SLA, 81%) was evident in cotransplanted animals when compared with 6-OHDA-lesioned animals. A significant restoration (P < 0.001) in [3H]-spiperone binding (77%), dopamine (DA) (82%) and 3,4-dihydroxy phenyl acetic acid (DOPAC) level (75%) was observed in animals cotransplanted with OECs and VMC in comparison to lesioned animals. A significantly high expression and quantification of tyrosine hydroxylase (TH)-positive cells in cotransplanted animals further confirmed the supportive role of OECs in viability of transplanted dopaminergic cells, which in turn may be helping in functional restoration. This was further substantiated by our observation of enhanced TH immunoreactivity and differentiation in VMC cocultured with OECs under in vitro conditions as compared to VMC alone cultures. The results suggest that cotransplantation of OECs and VMC may be a better approach for functional restoration in 6-OHDA-induced rat model of Parkinson's disease.

3,4-Dihydroxyphenylacetic Acid↗
PubMed2004

Systemic lupus erythematosus in Pakistan.

Clinical features of systemic lupus erythematosus (SLE) have been described from different geographical regions in the world, with some clinical differences among different racial groups. Although data on the characteristics of SLE in Pakistan is scarce, it is not uncommon in the South East Asian region. The purpose of this study was, therefore, to delineate the clinical pattern and disease course in Pakistani patients with SLE and to compare it with international data on lupus patients. A total of 196 patients with SLE fulfilling the clinical and laboratory criteria of the American Rheumatism Association admitted to the hospital between 1986 and 2001 were studied by means of a retrospective review of their records. Demographically, it was seen that SLE is a disease predominantly of females in their third decade, which is consistent with worldwide data. The mean age of presentation was 31 years (range 14-76) and the mean duration of follow up was 34 (4-179) months. Generally, there was less cutaneous (46%), arthritic (38%), serositis (22%) and renal involvement (33%) but more neuropsychiatric symptoms (26%) in our population. Eighty-six percent of patients were ANA positive, whereas anti dsDNA was positive in 74% of patients. Infections, renal involvement, seizures and thrombocytopenia were associated with poor prognosis (P < 0.05). This study is the first of its kind in Pakistan. The clinical and laboratory characteristics of SLE patients in our study place our population in the middle of a spectrum between the Caucasians and other Asian populations. It has shown that the clinical characteristics of SLE patients in this country may be different to those of its neighbors.

Adolescent↗
PubMed2004

Maximum tolerable dose of cyclophosphamide and azathioprine in Pakistani patients with primary renal disease.

OBJECTIVE: The immunosuppressive regimens, at present, mainly rely on western guidelines that were derived from studies conducted in western populations. No such study exists for South Asian population, which is home to almost two billion people different in both genetics and environment from west. Locally derived thresholds for side effects markedly different from western figures may warrant re-adjustment of current local immunosuppressive regimens that are at present based largely on western guidelines. In order to define optimum dose for Cyclophosphamide (CYC) and Azathioprine (AZA) based immunosuppressive therapy, we conducted this study to find out maximum tolerable doses of azathioprine (AZA) and cyclophosphamide (CYC) beyond which neutropenia and thrombocytepenia are most likely to occur in patients with primary renal pathology. METHOD: Patients with systemic vasculitis and idiopathic glomerulonephritis who were on CYC and AZA were identified through review of medical records at a tertiary care hospital in Pakistan (The Aga Khan University Hospital, Karachi). Patients were categorized under three principal diagnosis i.e. systemic lupus erythematosus (SLE), primary (idiopathic) glomerulonephritis (GN) and Wegener's granulomatosis (WG). The Receiver Operating Curve (ROC) was used to calculate the maximum tolerable dose for both CYC and AZA. RESULTS: We identified 94 patients aged 6-82 years (median 44.5 years) with primary renal disease (Wegener's granulomatosis n=13, Systemic lupus erythematosis n=62 and idiopathic glomerulonephritis n=19) who received CYC or AZA. Of these 94 patients, 36.2% (n=34) received CYC and 63.8% (n=60) received AZA. The mean dose of CYC was 1.54 +/- 0.50 mg/kg of body weight (range: 0.77-2.93). The mean dose of AZA was 1.64 +/- 0.59 mg/kg of body weight (range: 0.47-2.97). The maximum tolerable doses calculated for CYC and AZA were 1.25 mg/kg and 1.30 mg/kg of body weight respectively. The maximum tolerable dose for CYC and AZA among males could not be calculated, because of insufficient number of patients who developed neutropenia and thrombocytopenia. The maximum tolerable doses for CYC and AZA among females were 1.34 mg/kg and 1.03 mg/kg of body weight respectively. Also we found out that AZA was relatively more likely to cause neutropenia and thrombocytopenia (p=0.07). CONCLUSION: We thereby recommend that CYC should be initiated at a dose no more than 1 mg/kg of body weight and AZA at an initial dose of 0.75-1.0 mg/kg of body weight. The dose may be adjusted later on the basis of clinical response and laboratory reports.

Adolescent↗
PubMed2004

The fly ash influenced the heavy metal status of the soil and the seeds of sunflower. A case study.

In this study, four cultivars of sunflower (Helianthus annuus) were grown in the sandy loam soil, supplemented with graded (v/v) quantity (0, 20, 40, 60, 80, 100%) of the fly ash, released by the combustion of the coal from the thermal power plant. The presence of fly ash in the soil increased its porosity, water holding capacity, pH, E.C., C.E.C., the content of sulphate, carbonate, bicarbonate, chloride, phosphorus, potassium, calcium and various trace elements. However, in the seeds, except Fe, Pb, Mn and Zn, and other heavy metals remained untraced up to 40% of the fly ash, above that their quantity slightly increased but the values are very much under the permissible limits.

Carbon↗