Biomedical subjects
Publications and source records attributed to M Hegazy.
We present the results of using a simple Ilizarov fixator frame in treatment of 66 feet in 52 patients (mean age 8.5 years) of 58 relapsed and eight neglected clubfeet with grade III or IV severity with a mean follow-up of 40 (26-58) months. Our frame, in spite of being simple and easy for surgeons and patients to handle, achieved satisfactory correction comparable to the literature.
INTRODUCTION: Azimilide dihydrochloride blocks both the rapid (I(Kr)) and slow (I(Ks)) components of the delayed rectified K+ current; dofetilide blocks only I(Kr). Their efficacies were assessed on atrial flutter reentrant circuits in dogs with surgically induced right atrial enlargement. METHODS AND RESULTS: Multiple biopsies of the tricuspid valve and banding of the pulmonary artery in male mongrel dogs made them susceptible, about 3 weeks postoperatively, to stimulation-induced sustained (5 min or longer) atrial flutter. Azimilide 3 mg/kg administered intravenously (i.v.) terminated flutter in 8 of 8 dogs, but a slower, nonsustained arrhythmia could be reinduced in 5. In these 5 dogs, azimilide 10 mg/kg terminated flutter and prevented reinduction. This dose increased effective refractory period significantly more in the slow conduction zone (25%) than in the normal zone (17%) and increased flutter cycle length (37%). Termination followed progressive conduction delay in the slow zone of the reentrant circuit. Dofetilide 1 microg/kg i.v. terminated flutter in 6 of 6 dogs, but the arrhythmia could be reinduced. At 3 microg/kg, flutter terminated in all dogs and could not be reinduced. Dofetilide also increased the effective refractory period significantly more in the slow zone (17%) than in the normal zone (12%) and increased cycle length (33%), leading to interruption of the arrhythmia circuit. CONCLUSION: In the canine right atrial enlargement model of circus movement atrial flutter, both azimilide 10 mg/kg i.v. and dofetilide 3 microg/kg i.v. were 100% effective in terminating flutter and preventing reinduction. Efficacy relied on a similar mechanism of differentially prolonged refractoriness in the slow conduction component of the reentrant circuit where drug-induced termination occurred.
Although regular screening for diabetic retinopathy with ophthalmoscopy or retinal photography is widely recommended in the United States and Europe, few reports of its use in developing countries are available. We compared the performance of screening by retinal photography with that of indirect ophthalmoscopy by using data from a population-based survey of diabetes and its complications in Egypt. During that project, 427 persons with diabetes underwent an eye examination and fundus photography with a non-mydriatic camera through a dilated pupil. Data from the examinations of the right eye of each patient are presented. Ninety-two (22%) of the 427 retinal photographs were ungradable; in 58 eyes (63%), this was due to media opacity (42 eyes with cataract, 3 with corneal opacity, and 13 with both). Agreement between retinal photography and indirect ophthalmoscopy was poor (kappa = 0.33; 95% CI = 0.27-0.39) and primarily due to the large number of eyes (n = 79) with ungradable photographs that could be graded by ophthalmoscopy. None of these eyes was judged by ophthalmoscopy to have sight-threatening retinopathy. Fifty-four photographs were diagnosed with greater retinopathy than found on ophthalmoscopy. Retinal photography with the nonmydriatic camera through a dilated pupil is a useful method to screen for diabetic retinopathy in most adults in Egypt. However, such screening strategies have limited use in older persons and in persons with corneal disease or cataract.
We performed a cross-sectional, population-based survey of persons 20 years of age and older living in Cairo and surrounding rural villages. The purpose was to describe glycaemic control and the prevalence of microvascular and neuropathic complications among Egyptians with diagnosed diabetes, previously undiagnosed diabetes, impaired glucose tolerance, and normal glucose tolerance. A total of 6052 households were surveyed. The response rate was 76% for the household survey and 72% for the medical examination. Among people with previously diagnosed diabetes, mean haemoglobin A1c, was 9.0%. Forty-two per cent had retinopathy, 21% albuminuria, and 22% neuropathy. Legal blindness was prevalent (5%) but clinical nephropathy (7%) and foot ulcers (1%) were uncommon in persons with diagnosed diabetes. Among people with diagnosed diabetes, microvascular and neuropathic complications were associated with hyperglycaemia. Retinopathy was also associated with duration of diabetes; albuminuria with hypertension and hypercholesterolaemia; and neuropathy with age, female sex, and hypercholesterolaemia. Albuminuria was as common in people with previously undiagnosed diabetes (22%) as those with diagnosed disease (21%). Mean haemoglobin A1c was lower (7.8%) and retinopathy (16%) and neuropathy (14%) were less prevalent in people with previously undiagnosed disease. Ocular conditions, blindness, and neuropathy were prevalent in the non-diabetic population. The microvascular and neuropathic complications of diabetes are a major clinical and public health problem in Egypt.
The onset of diabetes relative to clinical diagnosis was estimated in Egyptians with non-insulin-dependent diabetes mellitus (NIDDM) based on the relationship between retinopathy and duration of diabetes. Between July 1992 and October 1993 the Diabetes in Egypt (DIE) Project performed a cross-sectional, population-based survey with clinical and laboratory follow-up to describe the prevalence of microvascular, neuropathic, and macrovascular complications among Egyptians > or = 20 years of age with diagnosed diabetes, previously undiagnosed diabetes, impaired glucose tolerance, and normal glucose tolerance. The sample of persons with diabetes diagnosed prior to the survey had medical examinations which included a dilated eye examination and retinal photographs. Generalized linear models were used to relate the probability of retinopathy to duration of diabetes. Among 218 persons with diabetes diagnosed prior to the DIE project, 87 (40%) had diabetic retinopathy. The onset of retinopathy was estimated to occur 2.6 years (p = 0.04) prior to clinical diagnosis. The estimated annual incidence of retinopathy was 5% and the estimated prevalence at the time of clinical diagnosis of diabetes was 12%. On the basis of reports that retinopathy does not occur until approximately 5 years after the development of diabetes, the onset of NIDDM was estimated to occur 7.6 years prior to its clinical diagnosis. This estimate of the onset of NIDDM in Egyptians is comparable to other estimates reported for US and Australian populations.
INTRODUCTION: The effects of a Class III agent, azimilide dihydrochloride, on atrial flutter circuits were studies in a functional model of single loop reentrant atrial flutter using dogs, 3 to 5 days after production of sterile pericarditis. METHODS AND RESULTS: A computerized mapping system was used to construct activation maps from 138 to 222 epicardial sites in the right atrium. Doses of 3, 10, and 30 mg/kg i.v. azimilide dihydrochloride were analyzed in 8 dogs in which sustained atrial flutter lasting more than 30 minutes was induced by burst pacing. Atrial flutter was always due to single loop circus movement reentry in the lower right atrium. At 3 mg/kg, azimilide dihydrochloride terminated atrial flutter in 2 dogs; however, atrial flutter was reinduced. At 10 mg/kg, atrial flutter was terminated in all 8 dogs but was reinduced in 4 dogs with slower rate. At 30 mg/kg, atrial flutter was terminated in the remaining 4 dogs and could not be reinduced. Atrial flutter cycle length always increased prior to termination. Isochronal activation maps showed that the increase in cycle length was due to additional conduction delays in the slow zone of the reentrant circuit. The site of termination was always located within the slow conduction zone situated in the lower right atrium between the line of functional conduction block and the AV ring. Effective refractory periods (ERPs) were measured at selected sites in the slow zone and normal zone at twice diastolic threshold for the 10 mg/kg dose. Azimilide preferentially prolonged ERP in the slow zone (42.4 +/- 20.1 msec, mean +/- SD) compared with the normal zone (23.3 +/- 15.4 msec, P < 0.0001). The increase in cycle length corresponded with the increase in ERP in the slow zone. CONCLUSIONS: In a functional model of circus movement atrial flutter, azimilide dihydrochloride terminates and prevents reinduction of atrial flutter by a preferential increase in refractoriness leading to further conduction delay and conduction block in the slow zone of the functional reentrant circuit.
We have tested the hypothesis that isoflurane potentiates non-depolarizing neuromuscular block via an increase in muscle blood flow. Anaesthesia was induced with thiopentone 4-5 mg kg-1 in 30 adult male patients of ASA physical status I or II and was maintained with 70% nitrous oxide in oxygen supplemented with either a bolus dose of fentanyl 4 micrograms kg-1 followed by an infusion of 1 microgram kg-1 h-1 (balanced anaesthesia group, n = 15) or 1.1% end-tidal isoflurane (isoflurane group, n = 15). Vecuronium 0.1 mg kg-1 was given for neuromuscular block. The force of contraction of the adductor pollicis of the thumb in response to ulnar nerve stimulation was recorded. Thenar muscle blood flow was measured continuously with a laser Doppler flowmeter. Times required for the first twitch in the train-of-four (T1) to recover to 25%, 75% and 90% of its control value were mean 26.3 (SD 5), 35.3 (10), 43.5 (7) min and 39.2 (15), 53 (12.5), 61.2 (10) min in the balanced anaesthesia and isoflurane groups, respectively (P < 0.01). Recovery index (time between T1 25% and 75%) was prolonged significantly in the isoflurane group. Administration of thiopentone significantly increased thenar muscle blood flow from 2.6 (1.9) and 2.2 (1.5) ml min-1/100 g to 19.2 (14) and 21.7 (16) ml min-1/100 g in the balanced anaesthesia and isoflurane groups, respectively (P < 0.001). The addition of fentanyl (balanced) or isoflurane to the anaesthetic mixture produced further increases in thenar muscle blood flow to reach, respectively, 26.2 (16) and 26.8 (13.6) ml min-1/100 g during steady state anaesthesia. Thenar muscle blood flow was comparable in the two groups throughout the study. We conclude that isoflurane prolonged vecuronium-induced neuromuscular block. This prolongation was not related primarily to increase in muscle blood flow.
The high concentration of zinc in the bovine pineal gland prompted us to investigate the existence of a zinc-binding protein in this organ. In this study, we report that the subcellular distribution of zinc in the bovine pineal gland is nonuniform, with the crude nuclear, mitochondrial, microsomal, and supernatant fractions having 0.264 +/- 0.038, 0.160 +/- 0.019, 0.130 +/- 0.016, and 0.287 +/- 0.010 micrograms zinc/mg protein, respectively. Furthermore, gel filtration studies using Sephadex G-75 and a 105,000 g supernatant fraction revealed two zinc binding protein peaks that bind 1.7 and 3.7 micrograms Zn++/mg protein, respectively. Furthermore, purification of the protein peak with an elution volume (ve/vo) of 2.06 on anion exchange chromatography (DEAE-A25) yielded a single protein peak which binds 10 micrograms zinc/mg protein. The comparative high performance liquid chromatographic (HPLC) profiles of the zinc-induced hepatic metallothionein isoform I (retention time = 17.39 min) and of the bovine pineal metallothionein-like protein isoform I (retention time = 17.49 min) are similar. Since zinc is a potent inhibitor of sulfhydryl-containing enzymes and receptor sites, we investigated the effects of zinc and found that it inhibited the binding of [3H]glutamate (IC 50 = 80 microM) and of [3H]spiroperidol (IC 50 = 0.6 mM) to the pineal membranes. The results of these studies are interpreted to indicate that the bovine pineal gland possesses an active and dynamic zinc homeostatic mechanism, whose precise function(s) remain(s) to be delineated.
Glycogen synthase I (EC 2.4.1.11) from rat and from rabbit skeletal muscle was phosphorylated in vitro by glycogen synthase kinase 4 (EC 2.7.1.37) to the extent of 0.8 phosphates/subunit. For both phosphorylated enzymes, the activity ratio (activity without glucose 6-P divided by activity with 8 mM glucose 6-P) was 0.8 when determined with low concentrations of glycogen synthase and/or short incubation times. However, the activity ratio was 0.5 with high enzyme concentrations and longer incubation times. It was found that the lower activity ratios result largely from UDP inhibition of activity measured in the absence of glucose 6-P. Inhibition by UDP was much less pronounced for glycogen synthase I, indicating that a major consequence of phosphorylation by glycogen synthase kinase 4 is an increased sensitivity to UDP inhibition.
Cell proliferation in carcinoma in the bilharzial bladder was studied in 92 patients in terms of the in vitro labeling index (LI), cell density (CD) and labeled cell density (LCD) using the in vitro 3H-Tdr technique. Cell proliferation was much greater in high than in low grade tumors and in deep than in superficial parts of the tumor, but was much less dependent on cell type; transitional cell cancer had the highest activity followed by squamous cell and adenocarcinoma. The probability of local recurrence after cystectomy decreased markedly when the LI exceeded 5.0%. The influence of the following three pre-operative radiotherapy regimens was studied: split-course (SC): the initial course consisted of 20 Gy in 10 treatments with a similar course was given after one week, hyper-fractionation using 17 treatments 0.6 Gy each on two successive days, this 2-day course of 20 Gy was repeated after one week, and concentrated irradiation consisting of two treatments, 6.0 Gy each with a gap of one week. Cystectomy was performed 14-20 days after treatment in all groups. Preoperative irradiation was generally associated with an increased probability of local control. The unfavorable influence of a high pretreatment LI was not noted after pre-operative irradiation. The CD was also reduced in proportion to the pretreatment LI. It is proposed that the response to irradiation was proportional to the initial proliferation activity and hence the prognostic significance of tumor grade and pretreatment LI was masked. Postirradiation tumor volume reduction was a strong predictor of treatment outcome. Concentrated irradiation was the least efficient pre-operative irradiation regimen and was associated with the least tumor volume reduction.
The rate of cell production in thirty-five cases of carcinoma in Bilharzial bladder was evaluated from the labelling index after in vitro incubation with [3H]TdR. Squamous cell carcinoma was the most frequent histological type in this series and had a median LI of 8.0% which corresponds to a potential doubling time of 5.9 days. In squamous cell tumours the LI increased with the histological grade. Transitional cell tumours had a somewhat greater LI. In all histological types the LI was significantly greater in the deep infiltrating parts of the tumour than in the superficial parts. The discrepancy between the estimated potential doubling time and the growth rate normally attributed to such tumours suggests the existence of an extensive cell loss factor. Areas of focal or diffuse mucosal hyperplasia were associated with increased LI.
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