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Biomedical subjects

A B Ahmed

Publications and source records attributed to A B Ahmed.

At least 19 recordsLinked to original sources
PubMed2006

The effect of metformin on blood glucose control in overweight patients with Type 1 diabetes.

AIMS: In a randomized, double-blind, cross-over study, we investigated the effect of metformin on blood glucose control and daily insulin dose in overweight patients with Type 1 diabetes. METHODS: We studied 15 C-peptide-negative patients, aged 48 +/- 12 years, with a body mass index of 31.3 +/- 2.6 kg/m(2). Each patient had a 'screening visit', followed by a 4-week 'run-in' period. This was followed by two separate 16-week 'study' (treatment) periods, separated by a 4-week 'wash-out' period. Patients received either metformin or placebo during the 'study' periods, in random order. RESULTS: HbA(1c) was significantly lower following 16 weeks of treatment with metformin (7.8 +/- 1.1%) compared with baseline (8.5 +/- 1.4%; P < 0.005) and placebo (8.6 +/- 1.2%; P < 0.005). Fasting plasma glucose, following 16 weeks of metformin treatment, was significantly lower (8.3 +/- 2.8 mmol/l) compared with baseline (12.4 +/- 3.0 mmol/l; P < 0.01) and placebo (12.6 +/- 3.4 mmol/l; P < 0.01). Compared with baseline (60 +/- 14 units), total daily insulin dose was significantly lower following the addition of metformin (50 +/- 13 units; P < 0.05) and this final total daily insulin dose in the metformin group was lower compared with placebo (58 +/- 12 units, P < 0.05). Body weight did not change following metformin or placebo treatment. CONCLUSION: Metformin can effectively improve glycaemic control and reduce the total daily insulin dose in overweight people with Type 1 diabetes.

Blood Glucose↗
PubMed2003

A survey of peri-operative use of magnesium sulphate in adult cardiac surgery in the UK.

We conducted a postal survey of cardiac anaesthetists in the UK, to determine the extent of magnesium sulphate (MgSO4) use and the main indications for its administration. Questionnaires were sent to anaesthetists at 35 UK hospitals undertaking adult cardiac surgery. Responses were received from 24 hospitals (69%) totalling 124 individual responses. Twenty-five (20%) of the anaesthetists responding to the questionnaire routinely gave magnesium other than in cardioplegia. The most common indications for administration were arrhythmia prophylaxis and treatment, myocardial protection, and the treatment of hypomagnesaemia.

Adult↗
PubMed2001

Tracheal intubation through the laryngeal mask airway using a gum elastic bougie: the effect of head position.

STUDY OBJECTIVE: To determine the effect of head position on success of tracheal intubation through a Laryngeal Mask Airway (LMA) using a gum elastic bougie. DESIGN: Randomized, controlled study. SETTING: Anesthesia and operating rooms of the University Hospital, Nottingham, UK. PATIENTS: 20 patients scheduled to undergo routine elective surgery requiring the use of an LMA for anesthesia. INTERVENTIONS: Blind placement of a gum elastic bougie through an LMA in two head positions. MEASUREMENTS AND MAIN RESULTS: Final position of the gum elastic bougie after removal of the LMA as determined by fiberoptic laryngoscopy. The gum elastic bougie was correctly sited in the trachea in the classical intubating position in 4/20 (20%) and in the neutral position in 0/20 (0%). There was no difference in the success of this technique between the two head positions. CONCLUSIONS: This technique cannot be recommended as an alternative to direct laryngoscopy following a failed intubation.

Head↗
PubMed2001

Cardiac output during hemiarthroplasty of the hip. A prospective, controlled trial of cemented and uncemented prostheses.

In a prospective, controlled study, we measured the effect on cardiac output of the introduction of methylmethacrylate during hemiarthroplasty for displaced fractures of the femoral neck. We treated 20 elderly patients who were similar in age, height, weight and preoperative left ventricular function with either cemented or uncemented hemiarthroplasty. Using a transoesophageal Doppler probe, we measured cardiac output before incision and at six stages of the procedure: during the surgical approach, reaming and lavage of the femoral canal, the introduction of cement, the insertion of the prosthesis, and in reduction and closure. We found that before the cement was introduced, there was no difference in stroke volume or cardiac output (p > 0.25). Cementation produced a transient but significant reduction in cardiac output of 33% (p < 0.01) and a reduction in stroke volume of 44% (p < 0.02). The introduction of cement did not affect the heart rate or mean arterial pressure. There was no significant difference in cardiac function on insertion of the prosthesis. Standard non-invasive haemodynamic monitoring did not detect the cardiovascular changes which may account for the sudden deaths that sometimes occur during cemented hemiarthroplasty. The fall in stroke volume and cardiac output may be caused by embolism occurring during cementation, but there was no similar fall during reaming or insertion of the prosthesis.

Aged↗
PubMed2000

Randomized, placebo-controlled trial of combination antiemetic prophylaxis for day-case gynaecological laparoscopic surgery.

In a randomized, double-blind trial, we compared i.v. ondansetron 4 mg (control), i.v. ondansetron 4 mg and cyclizine 50 mg (combination) and i.v. saline 0.9% (placebo), given after induction of standardized anaesthesia, for the prevention of nausea and vomiting (PONV) after day-case gynaecological laparoscopic surgery. Compared with placebo, fewer patients in the control group vomited (9/20 versus 11/59, P = 0.02) or needed rescue antiemetic (7/20 versus 9/59, P = 0.06) before discharge. Compared with the control, fewer patients in the combination group (n = 60) vomited (11/59 versus 2/60, P = 0.01) or needed rescue antiemetic (29/59 versus 2/60, P = 0.03) before discharge. The incidence of vomiting in the combination group was less than 5% overall. Compared with the control, the combination group had a significantly lower incidence (P = 0.001) and severity (P < 0.001) of nausea after discharge and more patients with no PONV at any time during the study (15/59 versus 27/60, P = 0.03). Unlike the placebo and control groups, no patient receiving combination prophylaxis was admitted overnight for PONV management.

Adult↗
PubMed2000

Cardiovascular pharmacology: new drugs and new indications.

This review presents a brief overview of some of the many exciting developments that are taking place in the field of cardiovascular pharmacology. Research continues to progress at a rapid rate, and we can expect many drugs to enter the clinical arena within the next few years. It must be borne in mind, however, that the pharmaceutical industry and hospital budgetary restrictions sometimes limit drug development and occasionally interrupt clinical trials, even before their results have been obtained.

Journal Article↗
PubMed1998

A physiology simulator: validation of its respiratory components and its ability to predict the patient's response to changes in mechanical ventilation.

We aimed to validate the mathematical validity and accuracy of the respiratory components of the Nottingham Physiology Simulator (NPS), a computer simulation of physiological models. Subsequently, we aimed to assess the accuracy of the NPS in predicting the effects of a change in mechanical ventilation on patient arterial blood-gas tensions. The NPS was supplied with the following measured or calculated values from patients receiving intensive therapy: pulmonary shunt and physiological deadspace fractions, oxygen consumption, respiratory quotient, cardiac output, inspired oxygen fraction, expired minute volume, haemoglobin concentration, temperature and arterial base excess. Values calculated by the NPS for arterial oxygen tension and saturation (PaO2 and SaO2), mixed venous oxygen tension and saturation (PvO2 and SvO2), arterial and mixed venous carbon dioxide tension (PaCO2 and PvCO2) and arterial pH were accurate compared with measured values. Subsequently, arterial gas responses to changes in minute volume of FiO2 were measured in 31 patients and were compared with the NPS prediction for each response. The 95% limits of agreement in predicting the magnitude of change were: arterial oxygen tension -2.07 to 2.47 kPa; PaCO2 -0.33 to 0.67 kPa; and pH -0.023 to 0.033. This investigation has validated respiratory components of the NPS. We recommend the NPS as a clinical tool for predicting the effects of alterations in mechanical ventilation in stable patients in the intensive care unit.

Adult↗
PubMed1998

The effect of the insulin analog lispro on nighttime blood glucose control in type 1 diabetic patients.

OBJECTIVE: Unmodified regular insulin has a long absorption tail, unlike the fast-acting insulin analog lispro, and may contribute to hypoglycemia in the early part of the night. A randomized crossover double-blind study was performed to compare blood glucose concentrations in the early part of the night in type 1 diabetic patients receiving lispro or unmodified regular human insulin, in random order, on 2 separate study days. RESEARCH DESIGN AND METHODS: We studied 23 C-peptide-negative patients; 12 were using a premeal plus basal insulin regimen, and 11 were using twice-daily insulin injections. Patients were admitted to the investigation unit at 5:00 P.M. and received a single dose of lispro or unmodified regular human insulin before the evening meal. In both groups, the NPH insulin dose remained unchanged. Identical meals and snacks were eaten at the same time during both study days. RESULTS: Average postprandial (6:00-10:00 P.M.) blood glucose concentrations were significantly lower after lispro therapy compared with human insulin (7.1 +/- 0.4 [SE] vs. 8.5 +/- 0.4 mmol/l, P = 0.0002). Nighttime (midnight to 4:00 A.M.) blood glucose concentrations were significantly higher after lispro compared with human insulin (10.3 +/- 0.4 vs. 9.1 +/- 0.4 mmol/l, P = 0.02). This difference was greatest in patients on the premeal plus basal insulin regimen (11.6 +/- 0.5 vs. 8.7 +/- 0.4 mmol/l, P < 0.001). The incidence of nocturnal hypoglycemia (midnight to 4:00 A.M., blood glucose < 3.5 mmol/l) was less with lispro compared with unmodified insulin (1 vs. 6 patients, P = 0.04). Nighttime (midnight to 4:00 A.M.) 3-hydroxybutyrate (102 +/- 13 vs. 51 +/- 7 mumol/l, P = 0.000) and glycerol (52 +/- 3 vs. 42 +/- 2 mumol/l, P < 0.01) were significantly higher after lispro therapy compared with human insulin in patients on the premeal plus bolus insulin regimen. CONCLUSIONS: Lispro can improve postprandial blood glucose control and reduce the incidence of nocturnal hypoglycemia at the expense of nocturnal hyperglycemia and hyperketonemia in patients using a premeal plus basal insulin regimen.

Adult↗
PubMed1998

Optimal provision of daytime NPH insulin in patients using the insulin analog lispro.

OBJECTIVE: Insulin lispro improves early postprandial blood glucose control but can result in late interprandial hyperglycemia. As an approach to resolving this problem, we performed a randomized, crossover study with four treatment arms, comparing the daytime metabolic profile after either premeal lispro alone or premeal lispro with optimal daytime NPH insulin and with standard human regular insulin. RESEARCH DESIGN AND METHODS: Twelve C-peptide negative type 1 diabetic patients were studied on four separate study days, at least 7 days apart. On each study day, patients received one of the four study insulin treatments, in random order, with identical meals and snacks. The four treatments were 1) premeal human regular insulin before lunch and supper at unchanged dose; 2) premeal lispro (unchanged dose) at lunchtime and dinner; 3) pre-lunch reduced-dose lispro (70%) before lunch and supper with supplemental lunchtime NPH and with a 6-h interval until dinner; and 4) pre-lunch reduced-dose lispro (70%) before lunch and supper with supplemental lunchtime NPH and with a 8-h interval until dinner. All patients were using their usual premeal plus basal insulin regimen during the period of the study, with human regular insulin before meals and NPH insulin at bedtime. RESULTS: Postprandial blood glucose concentrations (1230-1500) were lower after reduced or usual lispro dose compared with human regular insulin (5.5+/-0.2 and 5.6+/-0.2 vs. 8.2+/-0.5 mmol/l, P < 0.001), with no difference between the lispro doses. However, prepran-Dial (1800) blood glucose levels deteriorated to higher levels after usual-dose lispro alone compared with either human regular insulin (P < 0.05) or reduced-dose lispro plus NPH (P < 0.05) (8.9+/-0.3 vs. 7.1+/-0.8 and 6.4+/-0.4 mmol/l), with no difference between human regular insulin and reduced-dose lispro plus NPH. During the 2 h between the usual and delayed mealtime, blood glucose concentrations remained controlled on lispro plus NPH (2000: 6.5+/-0.4 mmol/l). CONCLUSIONS: Reduced-dose lunchtime lispro plus NPH maintained the improvement in postprandial blood glucose control with no deterioration in interprandial blood glucose control, even up to a late meal.

Adult↗
PubMed1998

Optimization of evening insulin dose in patients using the short-acting insulin analog lispro.

OBJECTIVE: A three-way, crossover, open-label, randomized study was designed to compare the evening and night (1800-0800) glycemic control when the evening premeal lispro dose was reduced by 20% and the bedtime basal NPH dose increased by 25%, or when the basal NPH dose was moved to before dinner at 1800, compared with the control arm on standard premeal human regular insulin and pre-bedtime NPH insulin. RESEARCH DESIGN AND METHODS: A total of 13 type 1 diabetic patients who use a premeal plus basal insulin regimen were studied on three separate days, with identical meals and snacks at the same times on each study day. On the control study day, patients received human regular insulin before dinner and NPH at bedtime in their usual doses. On another day, lispro was given before dinner with a dose reduction of 20%, and NPH at bedtime at 125% of usual dose. In the third regimen, the lispro and NPH were administered together in their usual dose before the evening meal by separate injections. The three regimens were tested in random order. RESULTS: Postprandial (1800-2200) blood glucose concentrations were lower after reduced-dose lispro compared with human regular insulin (6.0 +/- 0.3 [SEM] vs. 7.4 +/- 0.3 mmol/l, P < 0.05). Nighttime (2400-0400) blood glucose concentrations were not different (8.6 +/- 0.3 vs. 9.2 +/- 0.3 mmol/l, NS), and prebreakfast concentrations were also unchanged (7.7 +/- 0.9 vs. 8.7 +/- 0.8 mmol/l) after lispro with increased-dose NPH compared with standard insulin. By contrast, both nighttime (10.0 +/- 0.3 mmol/l, P < 0.05) and fasting glucose concentrations (10.8 +/- 0.6 mmol/l, P < 0.05) were significantly higher with dinnertime usual-dose lispro plus dinnertime usual-dose NPH compared with standard human insulin. Hypoglycemia at night (blood glucose < 3.0 mmol/l) did not differ between study days, but it was more frequent postprandially after dinner usual-dose lispro plus early NPH (2 vs. 7 patients, P = 0.062). CONCLUSIONS: With lower mealtime and higher basal bedtime insulin doses, patients using insulin lispro may be able to gain an overall improvement in evening blood glucose control without deteriorated nighttime glucose levels. Earlier basal NPH dosage alone does not ameliorate the nighttime hyperglycemia of short-acting insulin analog regimens.

3-Hydroxybutyric Acid↗
PubMed1993

Toxoplasma gondii in Saudi blood donors a serological study using three tests.

A total of one hundred and fifty Saudi blood donors were examined for Toxoplasma gondii antibodies (IgG-IgM) by three serological techniques, 50 normal cross matched controls were subjected to the same examination. The number of positive donors for IgG by Indirect Haemagglutination test (IHA) was 36 (24%), by Enzyme Linked Immunosorbent Assay (ELISA) was 70 (46.7%), and by Immunofluorescent test (IFAT) 74 (49.3%). As to IgM the ELISA and IFAT showed 3 positive cases among the blood donors (2%). Rheumatoid factor and antinuclear antibodies were done for positive cases, and showed no significant cross reaction, IgG antibodies were significantly high in donors than in controls. The three tests were more or less dependable. However regarding simplicity, specificity, accuracy and time consumption factor IFAT was recommended for Toxoplasma IgG for all blood donors to avoid the risk of in infection.

Animals↗
PubMed1992

A proposed four-element neutron-photon-beta thermoluminescence dosimeter.

It is common practice for a worker exposed to a mixed field with neutrons to wear both a photon-beta dosimeter and a neutron dosimeter. In this study, a thermoluminescence dosimeter has been designed and is proposed for use in mixed fields. The maximum applicable ranges of the mixed field can have photons with unknown energy from 20 keV to 2 MeV, betas with unknown energy from 147Pm to 90Sr-Y, and neutrons of known energy from thermal to 15 MeV. This proposed dosimeter (a combination of Harshaw beta-gamma thermoluminescence dosimeter and albedo neutron thermoluminescence dosimeter) has an advantage of using a minimum number of thermoluminescence dosimeter elements (therefore, making it less costly) to measure the dose equivalents in a mixed field of neutron, photon, and beta radiation. The basic dosimeter design consists of four thermoluminescence elements of TLD-600 and TLD-700 with different filtrations. Using the high-temperature peak methodology for TLD-600 and a filtration algorithm, the neutron, photon, and beta dose equivalents in a mixed field can be determined. The design, detection principle, and three dosimetric algorithms for three versions of the basic design of the four-element dosimeter are presented and discussed. The work that is required for the proposed dosimeter to be usable when it is made is also presented.

Algorithms↗
PubMed1989

Sensitivity of LiF thermoluminescent dosemeters to 6-18 keV photons.

The sensitivity of thermoluminescent dosemeters (TLD) to 6-18 keV photons at six different effective energies was determined using an extrapolation chamber as a dosimetric standard. Photons having effective energies of 8.1, 9.2, 13.5, 13.8 and 18.0 keV were generated from an x-ray machine using appropriate kilovoltages and aluminium filters. Photons from an 55Fe source (6 keV) were also used to broaden the range of energies investigated. Observed sensitivities relative to 137Cs were found not to differ from unity with the possible exception of 6.0 keV photons. At 6.0 keV the sensitivity was found to be 0.83 +/- 0.5.

Fluorides↗
PubMed1986

Thermoluminescence response of LiF to alpha radiation.

The relative alpha-to-gamma radiation sensitivity of LiF chips (TLD-100) was determined using 241Am and 137Cs. Sensitivity is expressed in thermoluminescence per unit of absorbed dose in grays. The relative sensitivity varied from 0.13 to 0.23 with a mean of 0.18 +/- 0.03. The chips were exposed at ambient temperature and pressure.

Alpha Particles↗