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Biomedical subjects

R Ahmad

Publications and source records attributed to R Ahmad.

At least 19 recordsLinked to original sources
PubMed1992

Suppression of the renin-angiotensin-aldosterone axis with erythropoietin therapy by a negative feedback loop.

To investigate the pathophysiology of hypertension in patients receiving recombinant human erythropoietin (rHuEpo) we studied its effects on the renin-aldosterone axis of chronic haemodialysis (HD) patients not receiving antihypertensive drugs. Nine severely anaemic normotensive HD patients received rHuEpo 50 U/kg bodyweight, thrice weekly after each HD. The dose was increased by 25 U/kg bodyweight every 4 weeks to a maximum of 100 U/kg or until an increase of Hb or Hct of 2 g/dl or 7% was achieved. Blood samples were taken after 30 min supine rest and while seated 10 min later after gentle ambulation. Results expressed as mean +/- SEM: therapy in normotensive HD patients by a negative feedback loop, before the development of hypertension.

Adult↗
PubMed1992

Haemodialysis-related porphyria cutanea tarda and treatment by recombinant human erythropoietin.

Haemodialysis-related porphyria cutanea tarda is a rare, but serious and mutilating skin condition, resulting from extremely high plasma porphyrin levels because of their inadequate clearance by haemodialysis. The treatment is very difficult as chloroquine is ineffective and venesection, the conventional treatment of this disease, is not always an option because of anaemia of end-stage renal disease. We report a case of haemodialysis-related porphyria cutanea tarda and her successful management by recombinant human erythropoietin treatment.

Erythropoietin↗
PubMed1992

Phlebotomy for erythropoietin-induced malignant hypertension.

Four patients on regular dialysis treatment whose blood pressure was well controlled, developed malignant hypertension while receiving maintenance recombinant human erythropoietin (r-Hu-EPO). None of these patients had a haematocrit greater than 35% at any stage, and clinically, none had any evidence of fluid overload. Initially, they were all managed by stopping r-Hu-EPO and intensification of antihypertensive therapy. However, none of the patients responded, and venesection of 500 ml of blood was performed in each case with swift and sustained response.

Adult↗
PubMed1992

Effect of fluoride concentrations on overdenture abutments.

This study evaluated the preventive effect of four concentrations of fluoride. Twenty-five extracted caries-free anterior teeth from patients aged 50-70 were prepared as overdenture abutments. The teeth were sectioned mesiodistally into two halves. The teeth were covered with a protective varnish, leaving a window on the root surface and one on the cut dentin of the occlusal. The root halves were randomly divided into 5 groups of 10 specimens and each group received a different 5-minute topical treatment prior to being placed in the demineralizing solution. The treatments were: Group 1: distilled H2O only; Group 2: 100 ppm F-, Group 3: 250 ppm F-, Group 4: 500 ppm F-; and Group 5: 1000 ppm F-. The teeth were cycled for 6 hours in a demineralizing solution and for 17 hours in a fluoride-free remineralizing solution. The cycling was maintained for 10 days. The root halves were sectioned and prepared for histologic examination. The depth of the lesions were measured from standardized photo-micrographs by means of a sonic digitizer. The conclusions were: (1) the lesions on the root surface were too small to be measurable, (2) the lesions on dentin were all of similar depth, and (3) the lesions had bands within them and the width of these bands showed a dose response to the fluoride concentration of the topical application.

Aged↗
PubMed1992

Portal vein thrombosis following sclerotherapy.

We present the case of a woman with idiopathic portal hypertension who underwent sclerotherapy for bleeding esophageal varices. She had a rebleed 27 months after complete eradication of esophageal varices. Endoscopy showed bleeding gastric varices. Ultrasonography, and later splenoportography, revealed a large thrombus in the right branch of the portal vein causing gross dilation of the portal and splenic vein. A proximal splenorenal shunt was done to decompress the portal system and hence gastric varices. Repeat endoscopy 4 weeks after surgery revealed complete disappearance of the gastric varices, while ultrasonography at 38 weeks showed marked decompression of the portal system with complete disappearance of the thrombus from the right branch of the portal vein. No new thrombus formation was seen.

Adult↗
PubMed1991

A spirostanol glycoside from Cestrum nocturnum.

A new steroidal saponin named nocturnoside A has been isolated from the methanolic extract of the fresh leaves of Cestrum nocturnum and has been characterized by 13C NMR spectroscopy to be 3-O-[beta-D-glucopyranosyl(1----3)-beta-D-glucopyranosyl(1----2)-beta-D- glucopyranosyl((3----1)-beta-D-xylopyranosyl)(1----4)-beta-D- galactopyranosyl) (25R)-spirost-5-ene-2 alpha,3 beta-diol.

Carbohydrate Sequence↗
PubMed1991

Low-dose desferrioxamine test for the diagnosis of aluminium-related bone disease in patients on regular haemodialysis.

Bone biopsy in an invasive method of diagnosing aluminium related bone disease (ABD). Toxic side-effects have been reported with the currently used 'high-dose Desferrioxamine (DFO) tests.' A low-dose DFO test was evaluated for the diagnosis of ABD in 28 symptomatic patients (13 male) on regular haemodialysis treatment. DFO 0.5 g diluted in 100 ml of 0.9% sodium chloride was given intravenously during the first 2 h of dialysis. Aluminium estimation before (t1) and 48 h after DFO challenge (t2) were made by DC plasma emission spectrometry. Following the DFO test bone biopsy was performed and the specimen stained for aluminium using soluchrome zurine. The DFO test was considered positive if the t2 concentration was 150 micrograms/l or treble the amount of t1. Nineteen patients (8 male) fell into this group and all except two had ABD. Of the nine remaining patients (5 male) who had a negative DFO test none had ABD. We conclude that ABD can be diagnosed safely in the majority of patients using a low-dose DFO test, thereby avoiding toxic side-effects.

Adult↗
PubMed1991

Delayed recovery of renal function in patients with acute renal failure due to accelerated hypertension.

Five patients with acute renal failure due to accelerated hypertension required regular dialysis treatment for 2-12 months (mean 8.8), before recovering sufficient renal function for dialysis to be withdrawn. Two patients who had prior evidence of chronic renal impairment remained off dialysis for 20 and 27 months before decompensating again to require regular dialysis treatment. Two patients with no prior history of renal disease have remained independent of dialysis for 32 and 48 months. The fifth patient was lost to follow-up after a 7 month dialysis-free period. Delayed recovery of renal function following accelerated hypertension is a distinct possibility and should be considered in such patients before contemplating long term strategies such as renal transplantation.

Acute Kidney Injury↗
PubMed1991

Bronchial reactivity in patients undergoing long-term haemodialysis for chronic renal failure.

Trapping of neutrophils within the lung occurs in patients undergoing haemodialysis and is also a possible mechanism in the pathogenesis of bronchial hyper-responsiveness. Falls in peak expiratory flow rate occur in most dialysis patients, and some develop overt asthmatic symptoms. To see whether these changes in airway function are secondary to increases in bronchial reactivity during haemodialysis, we therefore performed histamine challenge testing in 6 non-asthmatic patients before and after haemodialysis. No change in reactivity was observed, suggesting that haemodialysis does not commonly result in bronchial hyper-reactivity in non-asthmatic individuals.

Adult↗
PubMed1990

Haemodynamic effect of supraaortic ridge enhancement on the closure mechanism of the aortic valve and its implications in aortic valve repair.

The presence of the sinus of valsalva plays an essential part in the closing mechanism of the aortic valve. High-energy vortices are initiated at the upper limit of each sinus or supraaortic crest, and last during the whole valve closing time. An attempt was made to prove this hypothesis in vivo by intermittent augmentation of each supraaortic ridge. In a series of five dogs without cardiopulmonary bypass, pledgeted sutures were placed at the level of each crest and passed through tourniquets. In a series of three sheep, similar sutures were placed under direct vision with cardiopulmonary bypass. The supraaortic crests were augmented or maintained normal by tightening or loosening the tourniquets repeatedly. Simultaneous aortic and ventricular pressures and 2D- and M-mode echocardiography were recorded. In the dog series the results were unpredictable due to variability in the supraaortic crest enhancement because the sutures did not correspond to the anatomical crest. In the sheep series the sutures were correctly placed and M-mode echocardiography demonstrated a significant (p less than 0.01) shortening in systolic time. These results suggest the use of enhancement of the supraaortic crest as an adjunct technique in aortic valve repair.

Animals↗
PubMed1990

Hyperosmolar nonketotic hyperglycemia manifested as ascending polyneuropathy.

We have described a case of hyperosmolar nonketotic hyperglycemia atypically manifested as an ascending progressive predominantly motor neuropathy with sensory involvement. Although the patient noticed polydipsia, the lack of endogenous renal function prevented the expected polyuria and dehydration. Treatment with insulin produced such marked clinical improvement that 15 days after admission he was discharged home, fully mobile and self-sufficient. Because hyperosmolar nonketotic decompensation is uncommon and patients may initially have neurologic signs without a previous history of diabetes mellitus, the diagnosis may be overlooked.

Combined Modality Therapy↗
PubMed1990

Fractionated urinary cytology in the follow-up of bladder cancer.

Cytological examination of voided urine is an established investigation in urological practice. In a pilot study of 50 patients with histologically proven transitional cell carcinoma of the bladder, urine cytology was undertaken on samples from the initial, mid-stream and terminal parts of the void. Analysis showed that although the cell density varied between the samples in some cases, no part of the void was consistently richer in benign or malignant cells and similar cell types were seen in every sample from any given patient. It was concluded that fractionated cytology did not improve the diagnostic accuracy of urinary cytology and that any sample of urine was suitable for cytological purposes.

Adult↗