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Biomedical subjects

I Ahmed

Publications and source records attributed to I Ahmed.

At least 37 records · Page 2Linked to original sources
PubMed2005

Quantification of anion and cation release from a range of ternary phosphate-based glasses with fixed 45 mol% P2O5.

This article reports on the use of ion chromatography (IC) to investigate extensively the release profiles of both cations and anions and characterize the relationship between composition and degradation for a ternary-based Na(2)O-CaO-P(2)O(5) glass system developed as biomaterials. Studies are carried out on glasses with the formula 45P(2)O(5)-55(xCaO-Na(2)O) in deionized water, where x = 30, 35, and 40 mol%, using a cumulative release method, where the solution is changed at regular intervals. Degradation behavior is linear with time where the degradation rate shows an initial decrease with increasing CaO content. This rate then increases with a further addition of CaO. Cation release profiles follow similar trends to the degradation rates. Anion release profiles show a decrease for the PO(4) and linear polyphosphate (P(2)O(7) and P(3)O(10)) species with increasing CaO content. This decrease is attributed to the cross-linking of the Ca(2+) ions. In contrast, the cyclic P(3)O(9) anion exhibits the highest amount of anionic release, which demonstrates similar trends to the cations. These release patterns suggest that the cyclic P(3)O(9) species dominate the degradation rates. The proposed mode of degradation is a hydrolysis reaction, with the cyclic metaphosphate undergoing acid/base catalysis. The pH remains constant for the 30 and 35 mol% CaO glasses, and drops to about 5.5 for the 40 mol% composition. By using a response factor, it is possible to semiquantitatively analyze the additional peaks observed in the chromatograms. Suggestions are also put forward as to the identity of some of these unidentified peaks.

Absorbable Implants↗
PubMed2005

A review of ENT consultant postal questionnaires.

In recent years, there appears to have been an increase in the number of postal questionnaires being received by ENT consultants. Questionnaires with unsound methodology waste the time of those who send and receive them, as inferences cannot be made from their results. In this study,a review was performed on a sample of 19 questionnaire studies published in two ENT journals between January 1998 and December 2002. Each study was given a 30-point score, based on the quality of its methodology. The average score assigned to each study was 32 percent, suggesting that the quality of methodology was generally poor. These results should serve as a warning to those embarking on and those interpreting research of this kind.

Consultants↗
PubMed2005

Appendix mass: do we know how to treat it?

INTRODUCTION: The traditional management of appendiceal mass has been an initial conservative approach followed by interval appendicectomy. More recently, the necessity of interval appendicectomy has been questioned by a growing amount of evidence in the surgical literature. The aim of this study was to review the available scientific evidence and to determine how appendiceal masses are currently being managed in the Mid-Trent region by general surgeons. PATIENTS & METHODS: A literature search using Medline, Embase, Cinahl, HMIC and Biosis was carried out. A personal or telephonic survey of all consultants and specialist registrars working in general surgery in the Mid-Trent region (n = 67) was conducted recording their management protocol of 3 different clinical scenarios--a 14-year-old boy, a 29-year-old female and a 68-year-old male. Responses of the questionnaire were entered to a database in Microsoft Access 2000 and analysed. RESULTS: The results showed that there was difference of opinion on the management of appendix mass in either scenario. Appendectomy (interval or emergency) is still practised by 75% of general surgeons in the Mid-Trent region and less that 25% manage asymptomatic appendix mass without interval appendectomy. Additionally, specialist registrars appear more likely not to offer patients interval appendicectomy after successful conservative management (P < 0.05). CONCLUSIONS: At present, there is no agreed consensus on the management of appendiceal mass. There is a need to develop a protocol for the management of this common problem.

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↗
PubMed2005

Do citation classics in rhinology reflect utility rather than quality?

Citation rates have been suggested to be more of an indicator of utility than quality. The aim of this study was to apply measures of utility and quality to articles identified as citation classics in rhinology/anterior skull base surgery. There were 14 articles analysed in the study. The assessment of quality was performed by combining factors from previous publications on quality assessment and the various elements were categorised into four groups; quality of written article and publication, quality of research, quality of evidence-based methodology and quality of outcome. This study revealed that citation classics in rhinology/anterior skull base surgery were well-written and satisfied peer review in reputable journals in the specialty. Quality is satisfied by clarity of exposition and patient numbers. The research was generally asking an important question and the methodology overall was adequate and appropriate for the type of study performed. A good quality of research and outcome was demonstrated with a definite historical importance, and reports that stimulated further research and enquiry. Quality is not satisfied by the lack of randomised controlled trials, appropriate statistical analysis or patient criteria. In conclusion citation rates when considered as an individual measure, reflect utility rather than quality.

Bibliometrics↗
PubMed2004

Colonic pacing: a therapeutic option for the treatment of constipation due to total colonic inertia.

HYPOTHESIS: The treatment of constipation caused by total colonic inertia is problematic and its results are unsatisfactory. We speculated that colonic pacing would initiate electric activity in the inertial colon and effect rectal evacuation. METHODS: Nine patients with constipation due to total colonic inertia (age range, 39-52 years; 7 women, 2 men) were enrolled in the study. One pacing electrode was applied to each of the 4 potential colonic pacemaker sites, and 2 to 3 temporary recording electrodes were applied distally. A stimulator was embedded subcutaneously in the inguinal area. Home pacing was practiced after patients were trained; the recording electrodes were removed before home pacing was started. RESULTS: Colonic pacing evoked electric waves, which effected defecation in 6 of the 9 patients. Three of these 6 patients had spontaneous defecation after a few months of pacing, and their electrodes and stimulators were removed. In the other 3 of these 6 patients, the pacemakers are still in place and continue to effect rectal evacuation. Colonic pacing did not produce rectal evacuation in 3 patients and is believed to have failed because of an advanced stage of colonic inertia. CONCLUSION: Colonic pacing induced rectal evacuation in 66.6% of the patients with total colonic inertia. No complications were encountered. We suggest that colonic pacing be considered as a new therapeutic option in the treatment of total colonic inertia.

Adult↗
PubMed2004

Processing, characterisation and biocompatibility of iron-phosphate glass fibres for tissue engineering.

Iron-phosphate glass fibres based on the CaO-Na2O-Fe2O3-P2O5 system have been processed and characterised via thermal, XRPD, dissolution rates, diameter and biocompatibility studies. The compositions investigated were fixed at 50mol% P2O5, and the CaO content was varied between 30, 35 and 40mol%. The Fe2O3 was added in low amounts from 1-5mol%, substituting it for the Na2O mol%. The number of Tc (crystallisation temperature) peaks detected from the thermal analysis traces only showed correlation with XRPD analysis, for five out of the 15 compositions investigated. It has been suggested that either the crystalline phases had very similar Tc temperatures or that the other phase(s) were present in very small quantities. There was a good match seen with number of Tm (melting temperature) peaks picked up from the DTA traces, with the number of phases identified from XRPD analysis. The main phases identified from XRPD were NaCa(PO3)3, CaP2O6 and NaFeP2O7. Using network connectivity (NC), predictions on Qn species present within the compositions investigated were made. The predicted species (metaphosphates) matched with phases identified from XRPD analysis. A decrease in dissolution rates for the bulk glass and glass fibres was seen with an increase in CaO mol%, along with an increase in Fe2O3 mol%. An increase in fibre dissolution rates was seen with a decrease in diameter size. The biocompatibility studies were conducted using a conditionally immortal muscle precursor cell line derived from the H-2Kb-tsA58 immortomouse. It was found that iron-phosphate glass fibres containing 4-5mol% Fe2O3 was sufficient for cell attachment and differentiation. It was seen that myotubes formed along the axis of the fibres (which was indicative of differentiation). The biocompatibility of these compositions was attributed to the enhanced chemical durability of the glass fibres.

Animals↗
PubMed2004

Phosphate glasses for tissue engineering: Part 1. Processing and characterisation of a ternary-based P2O5-CaO-Na2O glass system.

This paper presents the results of a study of the thermal properties, X-ray powder diffraction (XRPD), NMR and solubility of a range of phosphate-based glasses. Ion release and pH measurements were also obtained. The compositions were limited by fixing the P2O5 mol% content at 45, 50 and 55 mol%, and varying the CaO mol% at 30, 35 and 40 mol%. Initial data collected from thermal analysis showed an increase in the Tg values, with increasing CaO mol%, as expected. An increase in crystallisation temperatures with increasing CaO mol% was also observed, with sharp peaks indicating the presence of single and/or double phases. Initial XRPD data revealed that the 45 mol% P2O5 precipitated a calcium bridged trimetaphosphate (Na4Ca[PO3]6) at the sodium oxide contents of 25 and 20 mol%, but at the 15 mol% level two phases formed, NaCa[PO3]3 and Ca2P2O7. The 50 mol% P2O5 compositions showed two sodium phosphate-rich phases [NaCa(PO3)3 and NaPO3] for the lower calcium containing compositions, and a calcium phosphate phase [CaP2O6] for compositions with higher CaO mol%. The 55 mol% P2O5 compositions, exhibited similar phases for the lower calcium containing compositions, and a single calcium phosphate phase (CaP2O6) was identified for the higher calcium containing composition. NMR analysis revealed the presence of Q1 and Q2 species in the 45 mol% P2O5 compositions, and Q2 species present in the 50 and 55 mol% P2O5 compositions. The non-linear data obtained from the thermal and solubility analyses conducted were attributed to the packing density of the 45 mol% P2O5 compositions. The solubility was seen to decrease with increasing CaO mol%, for all the glasses investigated, and all the compositions showed a gradual decrease in pH with time, and this was accounted for by the release of Na+ and Ca2+ ions into solution.

Biocompatible Materials↗
PubMed2004

Phosphate glasses for tissue engineering: Part 2. Processing and characterisation of a ternary-based P2O5-CaO-Na2O glass fibre system.

This paper presents the results of a study of the thermal properties, solubility and dimensions of a range of phosphate-based glass fibres (PB-GFs). The glass compositions were limited by fixing the P2O5 content to 45, 50 and 55 mol%, and varying the CaO mol% at 30, 35 and 40. PB-GFs were obtained from the 50 and 55 mol% P2O5 compositions; however, we were unable to obtain fibres from the 45 mol% compositions. This was linked to the cross-linked density, network connectivity and average chain length of the compositions studied. With regards to thermal parameters investigated, initial data showed an increase of the Tg and crystallisation temperatures with increasing CaO mol% at each fixed phosphate content. A decrease in Tg temperatures was also observed with increasing P2O5 content to 55 mol%. The crystallisation temperatures obtained for compositions with fixed phosphate at 55 mol%, showed a reverse pattern, with a decrease in values as compared to the fixed 50 mol% phosphate compositions. The diameters of the fibres all decreased with increasing RPMs as expected, and the solubility also increased with increasing RPMs. This was related to the increased surface area of the higher RPM fibres. There was also a decrease seen in solubility with increasing CaO mol%.

Biocompatible Materials↗
PubMed2004

Beneficial effects and mechanism of action of Momordica charantia juice in the treatment of streptozotocin-induced diabetes mellitus in rat.

This study investigated the beneficial effects and mechanism of action of the juice of Momordica charantia in streptozotocin (STZ)-induced diabetes mellitus in rats. Diabetes mellitus was associated with significant (p < 0.01) time course reductions in body weight, plasma insulin and the number of insulin positive cells per islet and significant (p < 0.01) time course elevation in blood glucose and osmolarity and systolic blood pressure compared to age-matched healthy controls. Oral intake of M. charantia juice by STZ-induced diabetic rats partially reversed all the diabetes-induced effects measured. Daily oral administration of M. charantia juice to STZ-induced diabetic rates significantly (p < 0.01) reduced the Na+- and K+-dependent absorptions of glucose by the brush border membrane vesicles of the jejunum compared to the responses obtained in STZ-induced diabetic rat. Either insulin (100 MM) or the fruit juice lyophilised extract (5 microg x ml(-1)) can stimulate 14C-D-glucose uptake in L6 myotubes. These effects were completely blocked by wortmannin, an inhibitor of phosphatidylinositol 3-kinase. High concentrations (10-200 microg x ml(-1)) of M. charantia juice extract inhibited 14C-D-glucose uptake in L6 myotubes compared to the control response. The effect of M. charantia treatment was also investigated on myelinated fibre abnormalities in the tibial nerve of STZ-induced diabetic and control rats. The results show that diabetes was associated with significant (p < 0.05) reduction in the mean cross-sectional myelinated nerve fibres, axonal area, myelin area and maximal fibre area compared to end controls. Treatment of STZ-induced diabetic rats with M. charantia juice normalised the structural abnormalities of peripheral nerves. The results indicate that M. charantia can exert marked beneficial effects in diabetic rats, and moreover, it can regulate glucose uptake into jejunum membrane brush border vesicles and stimulate glucose uptake into skeletal muscle cells similar to the response obtained with insulin.

Animals↗
PubMed2004

Are bedside features of shock reproducible between different observers?

Shock is often under-reported in children attending hospitals in developing countries. Readily obtainable features of shock (capillary refill time, temperature gradient, pulse volume, and signs of dehydration) are widely used to help prioritise management in the emergency assessment of critically ill or injured children. However, data are lacking on their validity, including, importantly, reproducibility between observers. Agreement of these signs was examined in 100 consecutive children admitted to a paediatric ward on the coast of Kenya. After an initial training of clinical sign recognition, there was moderate agreement for most features of cardiovascular compromise (delayed capillary refill > or =4 s, kappa = 0.49; and weak pulse volume, kappa = 0.4) and only substantial agreement for temperature gradient (kappa = 0.62). For hydration status, only in the assessment of skin turgor was there a moderate level of agreement (kappa = 0.55). Capillary refill times and assessment of pulse volume recommended by the recent American consensus guidelines achieved only a "low" moderate to poor interrater agreement, questioning the reliability of such parameters.

Child↗
PubMed2004

Management of sudden sensorineural hearing loss - a national survey.

The management of Sudden Sensorineural Hearing loss is a controversial issue and there is no universally agreed protocol in its management The aim of this study was to ascertain the referral trends, treatment strategies, and outcome of treatment adopted by the Consultant Otorhinolarygologists in this country. A postal questionnaire was sent to all 32 Consultants in the Republic of Ireland, which achieved 21(65.62%) responses. Patients were referred to 13(61.9%) respondents within two weeks of the onset of symptoms and 3(14.28%) Consultants were referred patients within twenty four hours of the onset of symptoms. All specialists routinely performed full blood count and erythrocyte sedimentation rate, 15(71.42%) routinely assess fasting blood sugar and 5(23.80%) investigate fasting lipids and perform a syphilis screen. MR imaging to outrule vestibular schwanoma is performed by 11(52.38%) respondents. When treated within two weeks of the symptoms 6(28.57%) of the respondents were optimistic about recovery of hearing upon treatment whereas 2(9.52%) considered recovery of useful hearing less likely if treated more than two weeks after onset The triple therapy with oral vasodilators, oral steroids, and Carbogen inhalation was favoured by 9(42.85%). Oral steroid was the sole therapeutic modality by 4(19.04%). The opinion of Consultants was that the referral trend from the primary care physician is appropriate and 20(95.23%). Consultants considered an optimistic outcome if treated within two weeks. The investigations and management protocol for sudden sensorineural hearing loss is not uniform which is consistent with the treatment strategies world wide.

Audiometry, Pure-Tone↗
PubMed2003

Efficacy and tolerability of borage oil in adults and children with atopic eczema: randomised, double blind, placebo controlled, parallel group trial.

OBJECTIVE: To study the efficacy and tolerability of borage oil, which contains a high concentration of gamma linolenic acid, in children and adults with atopic eczema. DESIGN: Single centre, randomised, double blind, placebo controlled, parallel group trial. SETTING: Acute district general hospital in Nuneaton, England. PARTICIPANTS: 151 patients, of whom 11 failed to return for assessment, leaving an evaluable population of 140 (including 69 children). INTERVENTION: Adults received four capsules of borage oil twice daily (920 mg gamma linolenic acid), and children received two capsules twice daily, for 12 weeks. MAIN OUTCOME MEASURES: Change in total sign score at 12 weeks measured with the six area, six sign, atopic dermatitis (SASSAD) score (primary endpoint); symptom scores, assessed on visual analogue scales; topical corticosteroid requirement, assessed on a five point scale; global assessment of response by participants; adverse events and tolerability. RESULTS: The mean SASSAD score fell from 30 to 27 in the borage oil group and from 28 to 23 in the placebo group. The difference between the mean improvements in the two groups was 1.4 (95% confidence interval -2.2 to 5.0) points in favour of placebo (P = 0.45). No significant differences occurred between treatment groups in the other assessments. Subset analysis of adults and children did not indicate any difference in response. The treatments were well tolerated. CONCLUSION: Gamma linolenic acid is not beneficial in atopic dermatitis.

Adult↗
PubMed2003

Study of the functional activity of the cecocolonic junction with identification of a "physiologic sphincter", "cecocolonic inhibitory reflex" and "colocecal excitatory reflex".

Radiologic, endoscopic and histomorphologic studies have suggested the presence of a sphincter at the cecocolonic junction (CCJ), while some investigators have denied its existence. To investigate the physiologic activity at the CCJ, the right colon was exposed during right hemicolectomy for early colonic cancer in 11 patients (mean age 43.6+/-12.3 years; 8 men). Three manometric catheters were introduced through colotomy to be separately located in the cecum, CCJ and ascending colon. We determined the CCJ pressure response to cecal and colonic distension by means of a balloon filled with saline in increments of 10 ml. The test was repeated after individual anesthetization of cecum, CCJ and ascending colon. The CCJ measured 1.6+/-0.6 cm in length and had a higher pressure ( p<0.05) than the cecum or colon. Large-volume cecal distension effected a significant CCJ pressure reduction which was augmented as the distension increased. Latency decreased upon increase of the distending volume. In contrast, the CCJ responded to large-volume colonic distension by pressure elevation which increased upon increase of the distending volume. Latency diminished with increased distension. Small-volume cecal or colonic distension effected no CCJ pressure response. The anesthetized CCJ did not respond to distension of the cecum or colon. Likewise, the CCJ did not exhibit a pressure response to distension of the anesthetized cecum or colon. The CCJ is a high-pressure zone which reacts to cecal or colonic distension by dilatation or narrowing, respectively. These data presumably denote the existence of a physiologic sphincter at the CCJ. We suggest that the CCJ pressure response to cecal or colonic distension is reflex and mediated through the cecocolonic inhibitory and colocecal excitatory reflexes, respectively. The role of the CCJ and related reflexes in colonic motility disorders needs to be studied.

Adult↗
PubMed2003

Antipsychotic drug treatment for elderly people with late-onset schizophrenia.

BACKGROUND: At least 0.1% of the world's elderly population have a diagnosis of schizophrenia that started late in life and prognosis may be made worse by delay and avoidance of treatment. OBJECTIVES: To assess the effects of antipsychotic drugs for elderly people with late-onset schizophrenia. SEARCH STRATEGY: We searched the Cochrane Schizophrenia Group trials register (September 2002). This register is compiled by methodical searches of BIOSIS, Cochrane Central Register of Controlled Trials (CENTRAL), CINAHL, Dissertation Abstracts, EMBASE, LILACS, MEDLINE, PSYNDEX, PsycINFO, RUSSMED, Sociofile, supplemented with hand searching of relevant journals and numerous conference proceedings. References of all identified studies were also inspected for more trials. SELECTION CRITERIA: All relevant randomised controlled trials that compared atypical antipsychotic drugs with other treatments for elderly people (at least 80% of whom should be over 65 years of age) with a recent (within five years) diagnosis of schizophrenia or schizophrenia like illnesses such as delusional disorder, schizoaffective disorder, schizophreniform psychosis or paraphrenia. DATA COLLECTION AND ANALYSIS: All citations were inspected by the principal reviewer (SA) and papers ordered and re-inspected (by IA, NAQ, SP) to ensure reliable selection. Methodological quality of trials would have been assessed using the Cochrane Reviewers' Handbook criteria and data would have been independently extracted. Data were to have been excluded if loss to follow up was greater than 50%. For homogeneous dichotomous data the relative risk (RR), 95% confidence interval (CI), and the number needed to treat (NNT) and number needed to harm (NNH), were to have been calculated based on an intention-to-treat basis. MAIN RESULTS: Electronic searching produced 119 references, 65 of which were selected for examination of the full text. These referred to 38 studies. Not one study met the entry criteria for this review. Most were randomised but involved elderly people with chronic schizophrenia. Four trials involved people with schizophrenia, and did include a minority who suffered from paraphrenia. Outcomes for this sub-group, however, were not reported. One randomised study (n=18) did focus on late onset schizophrenia, but unfortunately the two treatments under evaluation, remoxipride and thioridazine, have both been withdrawn from use. REVIEWER'S CONCLUSIONS: There is no trial-based evidence upon which to base guidelines for the treatment of late onset schizophrenia. This review highlights the need for good quality controlled clinical trials to address the effects of antipsychotic drugs for this group. Such trials are possible. Until they are undertaken people with late onset schizophrenia will be treated by doctors using clinical judgement and habit to guide prescribing.

Age of Onset↗
PubMed2002

Differential modulation of growth and glutathione metabolism in cultured rat astrocytes by 4-hydroxynonenal and green tea polyphenol, epigallocatechin-3-gallate.

Oxidative stress has been implicated in the pathogenesis of cancer and prominent neurodegenerative disorders such as Alzheimer's and Parkinson's diseases. Apoptosis and cell cycle deregulation appear to be the mode of cell death in these disorders. Green tea polyphenol, epigallocatechin-3-gallate (EGCG) has been shown to be a potent antiinflammatory, apoptotic and cancer chemopreventive agent. 4-Hydroxynonenal (HNE), a by-product of lipid peroxidation (LPO), has been reported to induce apoptosis and inhibit growth in many cell systems including neuroglial cultures. We have studied both the dose and time dependent effects of HNE and EGCG on the viability of primary astrocyte cell cultures prepared from neonatal rats. HNE was found to be cytotoxic at a higher dose (0.1 mM) and markedly reduced (up to 80%) the astrocyte viability while EGCG did not appear to be cytotoxic under similar conditions. In addition, we have also studied the alterations in glutathione (GSH) and LPO levels and the activities of GSH metabolizing enzymes after treatment with HNE and EGCG. A 40% decrease in GSH level and a moderate increase in LPO were observed in HNE treated cells suggesting an increase in oxidative stress. HNE treatment caused a 50% decrease in GSH reductase and a 35% increase in GSH peroxidase activities. Although HNE treatment did not lead to any significant alterations in GSH-S-transferase (GST) activity, an increased expression of GST isoenzymes was seen following the exposure to HNE. EGCG treatment caused a significant increase in LPO even in the presence of elevated GSH content. In contrast to HNE, EGCG treatment resulted in a significant decrease (50%) in the activity and expression of GSTs. Treatment of astrocyte cultures with HNE, resulted in a severe impairment in mitochondrial respiration as measured by MTT exclusion assay, while treatment with EGCG had no effect on mitochondrial respiratory activity. Both HNE and EGCG were found to initiate apoptosis in astrocytes as measured by DNA fragmentation assay. However, HNE seems to be a stronger apoptotic and cytotoxic agent than EGCG. These results suggest that HNE and EGCG differentially modulate oxidative stress and regulate the growth and survival of astrocytes.

Aldehydes↗