Biomedical subjects
P Prasad
Publications and source records attributed to P Prasad.
Quantification of midline shift as a predictor of poor outcome following head injury.
A retrospective study of patient outcome, based on admission computed tomography, was carried out in 75 consecutive patients with head injury. Computed tomography data collected included the type and extent of intracranial hemorrhage, the extent of midline shift, and the ratio of midline shift compared with the extent of intracranial hemorrhage. Midline shift was considered to be out of proportion to intracranial hemorrhage when the midline shift of the septum pellucidum exceeded the extent of the hemorrhage as measured radially from the inner table of the skull. When computed tomography data were analyzed by logistic regression, significant predictive factors for poor outcome were intracranial hemorrhage (34%), intracranial hemorrhage with midline shift (61%), and midline shift out of proportion to the extent of intracranial hemorrhage (88%). When patient outcome and mortality rates are considered, our study indicates that midline shift out of proportion to the extent of intracranial hemorrhage is a highly useful predictor of poor patient outcome following head injury.
Accelerated ocular neovascularisation in diabetics following posterior chamber lens implantation.
Two well controlled non-insulin dependent diabetics with background retinopathy underwent endocapsular lens extraction with in-the-bag posterior chamber implantation. In the postoperative period rubeosis iridis set in abruptly. The fellow eyes showed no progression of retinopathy and the diabetic status showed no deterioration. The cause of neovascularisation and the role of intra- versus extracapsular extraction with implantation are discussed.
The winnowed wisdom of medicine.
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Diagnosis of olfactory neuroblastoma by cytology.
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The evolution of medicine.
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A case of pure primary squamous cell carcinoma of the breast diagnosed by fine needle aspiration biopsy.
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Revisiting medical ethics.
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The divarication of the medical ethos.
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Influence of short-term water deprivation on antipyrine disposition.
The effects of acute (96 h) water deprivation on the disposition kinetics of antipyrine and hepatic cytochrome P-450 content were investigated in male rats. The disposition kinetics of antipyrine in rats deprived of water for 96 h was altered significantly: the total body clearance and steady-state volume of distribution decreased by 27.1 and 22.4%, respectively, as compared to control rats. There was no significant change in the disposition rate constant as a result of simultaneous changes in the volume of distribution and clearance. There was a 51.4% decrease in the hepatic cytochrome P-450 content in water-deprived rats. These results suggest that the pharmacokinetic changes observed in acute water deprivation with a model drug, antipyrine, are related to a decrease in total body water and to a reduced amount and/or activity of the hepatic microsomal oxidative enzymes.
Extragenital syphilitic chancres.
Two patients with extragenital chancres are presented to emphasize unusual expressions of primary syphilis. The clinical presentations and differential diagnosis of extragenital chancres are discussed.
Mechanism of spinal injury due to caudocephalad accleration.
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Effect of acute water deprivation on renal function in rats.
The effect of acute water deprivation for 96 h on renal function was studied in male Sprague-Dawley rats. The glomerular filtration rate (GFR) and the effective renal plasma flow (ERPF) were estimated using inulin and p-amino hippuric acid (PAH), respectively, as model compounds. Acute water deprivation caused a significant decrease (44 per cent) in the GFR without altering the ERPF. These results indicate that a proper dosage adjustment may have to be made in the dehydration condition, especially for drugs whose disposition is dependent on GFR.
Bilateral acute retinal necrosis--a case report.
A 42 year old man presented with acute bilateral uveitis and necrotizing retinitis. Systemic investigations including test for AIDS and CMV retinitis were negative. Despite oral Acyclovir, both eyes progressed rapidly to retinal detachment with loss of vision. Early recognition is necessary to diagnose the bilateral acute retinal necrosis syndrome and initiate treatment. Bilateral acute retinal necrosis (BARN) is a term first coined by Young and Bird in 1978 although the syndrome had been originally described by Urayama et al as an unilateral condition. This syndrome is characterized by the triad of acute confluent peripheral necrotizing retinitis, moderate to severe vasculitis and vitritis in an otherwise healthy individual. Rhegmatogenous retinal detachment occurs within two to three months of the onset of the disease and the second eye is involved in 36% of patients, usually within 6 weeks. We herein report a patient who presented with simultaneous BARN leading to retinal detachment in a matter of days. Also, to our knowledge this is the first report of this condition in India.
Cluster headache or narrow angle glaucoma?
A 47 year old man with episodes of attacks of pain, redness and mild blurring of vision was investigated for narrow angle glaucoma in view of shallow anterior chambers and a cupped optic disc. The history was reviewed following a spontaneous attack in hospital, which had features other than acute glaucoma. A diagnosis of cluster headache was made on the basis of tests. Cluster headache has been defined as unilateral intense pain, involving the eye and head on one side, usually associated with flushing, nasal congestion and lacrimation; the attacks recurring one or more times daily and lasting 20 - 120 minutes. Such attacks commonly continue for weeks or months and are separated by an asymptomatic period of months to years. This episodic nature, together with unilaterality and tendency to occur at night, closely mimics narrow angle glaucoma. Further, if patients have shallow anterior chambers and disc cupping, the differentiation becomes more difficult yet critical. Resource to provocative tests is often the only answer as the following case report demonstrates.
Disposition of procainamide and N-acetylprocainamide in protein-calorie malnutrition.
The influence of dietary protein deficiency on the disposition of procainamide (PA) and its major metabolite, N-acetylprocainamide (NAPA) was investigated in male Sprague-Dawley rats fed for 4 weeks on a 23 (control) or a 5% (low) protein diet ad libitum. Procainamide and N-acetylprocainamide in plasma and urine were determined by a sensitive and specific HPLC assay using a cation-exchange column. After an iv dose of 50 mg/kg procainamide hydrochloride, the average mean residence time (MRT) was approximately 82% higher, while the total plasma clearance (CI) per kg of body weight and terminal elimination rate constant (k) were significantly decreased by 46 and 49%, respectively, in the protein-deficient animals. No significant differences were found in the two groups of animals with respect to the apparent steady state volume of distribution (Vss). Although the percentage of PA recovered unchanged in the urine over 48 hr was not significantly different between control and protein-deficient animals, rats on a low protein diet excreted a smaller percentage of the administered PA dose (mean +/- SE, 19.0 +/- 4.0 vs. 30.8 +/- 1.4%) as NAPA. In addition to the apparent decrease in metabolic clearance (CIm) to NAPA (6.8 +/- 1.4 vs. 19.9 +/- 2.3 ml/min/kg) in the protein-deficient rats, there was a 55% decrease in the renal clearance of PA. There appeared to be no significant difference in the disposition characteristics of NAPA (i.e. MRT, Vss, CI, and k) between the two groups of animals after a 25 mg/kg dose of N-acetylprocainamide hydrochloride.(ABSTRACT TRUNCATED AT 250 WORDS)