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Biomedical subjects

E Amin

Publications and source records attributed to E Amin.

10 recordsLinked to original sources
PubMed2005

Changes in immediate early gene expression in the rat brain after unilateral lesions of the hippocampus.

Activity of the immediate early genes c-fos and zif268 was compared across hemispheres in rats with unilateral, excitotoxic lesions of the hippocampus (dentate gyrus and CA fields 1-4). Counts of the protein products of these genes were made shortly after rats performed a test of spatial working memory in the radial-arm maze, a task that is sensitive to bilateral lesions of the hippocampus. Unilateral hippocampal lesions produced evidence of widespread hypoactivity. Significant reductions in immediate early gene counts were observed within all three anterior thalamic nuclei, as well as the entorhinal, perirhinal, and postrhinal cortices, and much of the subicular complex. In contrast, no observable changes were detected in the anterior cingulate, infralimbic or prelimbic cortices, as well as several amygdala nuclei, even though many of these regions receive projections from the subiculum. Instead, the immediate early gene changes were closely linked to sites that are thought to be required for successful task performance, with both immediate early genes giving similar patterns of results. The findings support the notion that the anterior thalamic nuclei, hippocampus, and parahippocampal cortices form the key components of an interdependent neuronal network involved in spatial mnemonic processing.

Animals↗
PubMed2004

Novel spatial arrangements of familiar visual stimuli promote activity in the rat hippocampal formation but not the parahippocampal cortices: a c-fos expression study.

The novelty of a cue may arise from the presence of an element that has not previously been experienced or from familiar elements that have been rearranged. The present study mapped the anatomical basis of responding to this second form of novelty. For this, rats were trained on a working memory spatial task in a radial-arm maze in a cue-controlled environment. On the final test day the positions of the familiar, extra-maze cues were rearranged for half of the rats (group Novel). The spatial configuration of the cues now matched that of the control rats (group Familiar). Neuronal activation, as measured by the immediate early gene, c-fos, was then compared between the two groups. Rearrangement of visual stimuli led to significant increases in Fos-positive cells in various hippocampal subfields (rostral CA1, rostral CA3 and rostral dentate gyrus) as well as the parietal cortex and the postsubiculum. In contrast, no changes were observed in other sites including the perirhinal cortex, postrhinal cortex, lateral and medial entorhinal cortices, retrosplenial cortices, or anterior thalamic nuclei. These results highlight the selective involvement of the hippocampus for processing novel rearrangements of visual stimuli and suggest that this involvement is intrinsic as it is independent of the parahippocampal cortices. This pattern of Fos changes is the mirror image of that repeatedly found for novel individual stimuli (perirhinal increase, no hippocampal change), demonstrating that these two forms of novelty have qualitatively different neural attributes.

Animals↗
PubMed2001

Perirhinal cortex and place-object conditional learning in the rat.

The present study examined whether excitotoxic lesions of the perirhinal cortex can affect acquisition of a place-object conditional task in which object and spatial information must be integrated. Testing was carried out in a double Y-maze apparatus, in which rats learned a conditional rule of the type, "In Place X, choose Object A, not Object B (A+ vs. B-); in Place Y, choose Object B, not Object A (A- vs. B+)." Perirhinal cortex lesions significantly impaired acquisition of this task while sparing performance of an allocentric spatial memory task performed in a radial arm maze. Perirhinal cortex lesions also had no apparent effect on a 1-pair object discrimination task performed in the double Y maze or on retention and acquisition of 4-pair concurrent discrimination problems performed in a computer-automated touch screen testing apparatus. The results suggest that, although the perirhinal cortex and hippocampus can be functionally dissociated, their normal mode of operation includes the integration of object and spatial information.

Animals↗
PubMed1989

Medullary carcinoma of the breast: mammographic and US appearance.

Medullary carcinoma of the breast is an uncommon tumor, which may mimic a benign mass at both mammography and ultrasonography (US). A total of 24 medullary carcinomas visible at mammography appeared as round or oval, noncalcified masses with varying degrees of marginal lobulation. In six of the 24 patients, US demonstrated well-defined masses with an inhomogeneous, hypoechoic texture. There was no attenuation of sound, and all lesions showed enhanced through transmission.

Adult↗
PubMed1984

Enhancement of renal venous renin ratios by intravenous hydralazine in renovascular hypertension.

Renal venous renin (RVR) studies were done in 34 patients with moderate-to-severe hypertension before (unstimulated) and after (15- and 30-minute samples) a 20-mg bolus of i.v. hydralazine. The unstimulated lateralizing ratio of angiographically abnormal kidney or ipsilateral (I) to contralateral (C) RVR of greater than or equal to 1.5 was found in 69%, and the unstimulated ratio of I-inferior vena cava (IVC) renin below renal veins (I-IVC)/IVC (index of reduced renal blood flow) of greater than or equal to 0.48 was present in 50% of 16 patients (10 unilateral and 6 bilateral renal artery stenosis). The I/C and I-IVC/IVC ratios were abnormal in 100% and 88%, respectively, in 1 or both of the posthydralazine sampling in these patients. Hydralazine increased the absolute RVR from the ischemic kidney more than the contralateral kidney and did not result in new false-negative or positive I/C ratios. It is concluded that hydralazine stimulation of RVR is a safe and reliable way to determine the functionally significant pressor kidney in renovascular hypertension.

Clinical Enzyme Tests↗
PubMedDate not supplied

Essential fatty acid status in infants and children with chronic liver disease.

The relationship between essential fatty acid (EFA) status and degree of hyperbilirubinaemia and oxidant stress in infants and children with chronic liver diseases was evaluated. Thirty patients with chronic cholestasis and 30 with liver cirrhosis were examined; 30 healthy subjects served as controls. Patient groups had significant decreases in EFAs and significant elevation of total bilirubin. Levels of thiobarbituric acid reactive substances were significantly raised and were significantly inversely correlated to decreased EFA levels. There were also significant decreases in retinol, alpha-tocopherol and alpha-tocopherol/total lipids ratio, which had significant positive correlations with decreased EFA levels. Infants and children with chronic liver diseases have a high risk of EFA deficiency correlated with progressive elevation of serum bilirubin and progressive deterioration of oxidant status.

Adolescent↗