Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P50583 (asymmetrical)
 12,197 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A 58-year-old man developed progressive difficulty with comprehension and verbal output with dementia. Positron emission tomography with 18F 2-fluoro-2-deoxy-D-glucose demonstrated asymmetrical frontal and anterior temporal lobe loss of glucose use. Scopolamine infusion (0.3 mg) did not influence memory. Postmortem studies revealed evidence of Pick's disease, with Pick bodies, loss of somatostatin, preservation of choline acetyltransferase and immunostaining with neurofilament antibodies. Pharmacological challenge and positron imaging offer valuable means for the noninvasive assessment of dementing illness. The contributions of functional imaging to our knowledge of frontal involvement in dementing illness are reviewed.
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PMID:Functional imaging, the frontal lobes, and dementia. 840 92

Hypoglycaemia may cause transient cognitive impairment and neurological deficits that are frequently unilateral. The effect of mild hypoglycaemia (serum glucose level 3.4 +/- 0.1 mmol/l; mean +/- SEM) on regional cerebral blood flow and cerebrovascular resistance was studied in eight right-handed children with insulin-dependent diabetes mellitus (age 14.9 +/- 0.7 years; diabetes duration 7.4 +/- 1.1 years; six males) using the intravenous xenon-133 clearance method. Global mean cerebral grey and white matter blood flow, adjusted to mean pCO2 of cohort, showed a trend towards an increase from 54.7 +/- 3.5 ml.100 g-1.min-1 at baseline euglycaemia to 58.0 +/- 4.1 ml.100 g-1.min-1 during hypoglycaemia (p = 0.075). Statistically significant changes were seen in global mean cerebral grey matter blood flow, as indexed by initial slope, which increased from 88.0 +/- 6.5 min-1 before hypoglycaemia to 96.3 +/- 7.2 min-1 during hypoglycaemia (p < 0.05). Cerebral grey matter blood flow was significantly higher in the right hemisphere compared to the left during hypoglycaemia (p < 0.01) but not at baseline euglycaemia. Measurements of global cerebrovascular resistance showed a borderline decrease from 1.64 +/- 0.11 to 1.54 +/- 0.11 mm Hg.ml-1.100 g-1.min-1 (p < 0.09). In conclusion, mild hypoglycaemia is associated with increases in cerebral blood flow which are greater in grey matter flow indices and in the right hemisphere. We speculate that asymmetrical cerebral blood flow changes may explain the frequent laterality of neurological deficits during severe hypoglycaemia.
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PMID:Regional cerebral blood flow during hypoglycaemia in children with IDDM. 859 24

A female alcoholic presented with Wernicke's encephalopathy subsequent to administration of diazepam and glucose (without thiamine) for treatment of withdrawal seizures. Nystagmus and cerebellar ataxia quickly resolved when administered thiamine, although severe global amnesia consistent with Korsakoff's syndrome persisted. Magnetic resonance imaging (MRI) revealed infarction of the right temporal lobe with hippocampal atrophy, but no lesions of thalamus or atrophy of mammillary bodies. Positron emission tomography (PET) confirmed decreased cerebral metabolic rates for glucose (CMRglu) in the right temporal lobe corresponding to MRI findings, but also significant metabolic asymmetry of dorsal thalamus, i.e. reduced CMRglu in left versus right. This patient is unique in that neuroradiological findings revealed intact mammillary bodies and suggest asymmetrical dysfunctions (structural right temporal and functional left diencephalic) to produce her profound amnesia.
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PMID:Severe global amnesia presenting as Wernicke-Korsakoff syndrome but resulting from atypical lesions. 868 98

There are a number of noninvasive imaging methods in patients with dementia, including X-ray CT, MRI, SPECT and PET. Anatomical imaging using CT and MRI is often used for assessing severity of brain atrophy, which is commonly seen in patients with dementia. However, the early detection of brain abnormalities seem to be limited with these methods. Brain functional studies using radionuclide techniques have been recently developed with introduction of a variety of new radiopharmaceuticals. Among them, brain perfusion SPECT which is clinically available in most of the hospitals, is considered as a powerful means for accurate diagnosis and assessment of severity of dementia. Hypoperfusion is commonly seen in bilateral parieto-temporal cortex (association cortex) in patients with Alzheimer's disease. Frontal hypoperfusion is seen in the advanced cases of Alzheimer's disease. This disease is easily differentiated with multi-infarct dementia where multiple asymmetrical hypoperfusion is seen in the brain cortex on SPECT. More importantly, such functional abnormality is often observed in patients with normal findings in CT or MRI, indicating clinical value of brain perfusion SPECT for early detection of Alzheimer's disease. Bilateral hypoperfusion is noted in the frontal cortex in patients with Pick disease. Recently biochemical imaging can be obtained with positron emission tomography (PET) using various physiological tracers labeled with C-11, N-13, O-15, and F-18. Cerebral perfusion, metabolism and receptor functions can be quantitatively measured in vivo. The PET study nicely demonstrated that hypometabolism in bilateral parieto-temporal cortex in patients with Alzheimer's disease. Furthermore, glucose metabolism is considered to be further suppressed compared to perfusion, indicating suppression of brain synaptic function in this disease. In conclusion, brain functional imaging using SPECT and PET is useful for the detection and evaluation of a variety of dementia.
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PMID:[Image analysis in patients with dementia]. 875 24

A hypothesis that, in the rat, fluid circulates across the placenta, with circulation being maintained by active transport of Na+ from mother to fetus, has been tested. Transfer of 51Cr-EDTA from mother to fetus and from fetus to mother has been measured and the respective unidirectional transfer constants, Kmf and Kfm, have been calculated. Immediately before the transfer measurement, the fetuses were injected intravenously with 10 microliters of isotonic glucose (controls); with 30 or 300 microliters of isotonic saline; or with 10, 30, or 60 microliters of 9% NaCl. In controls, Kmf of 51Cr-EDTA was 2.0 +/- 0.6 microliters/min, and Kfm was 4.3 +/- 1.0 microliters/min. Injecting the fetus with NaCl had no effect on Kmf, whereas the Kfm was increased significantly in a dose-dependent way. In other experiments, 51Cr-EDTA was injected into nephrectomized maternal animals, and the radioactivity of maternal and fetal plasma was followed for 30 h. The time course of fetal plasma radioactivity supported the thesis that the transfer of 51Cr-EDTA across the rat placenta is highly asymmetrical.
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PMID:Effect of NaCl load administered to the fetus on the bidirectional movement of 51Cr-EDTA across rat placenta. 903 41

Energy metabolism and glycolysis of normal human term placental trophoblast in two-sided culture was investigated during differentiation from cytotrophoblast to syncytiotrophoblast, because glycogen metabolism is abnormal in several trophoblast related pregnancy diseases, including pre-eclampsia. After initial recovery of energy and cytoplasmic NADH/NAD+ redox by 24 h of culture, measures of cellular energy state, [ATP], [ADP], [ATP]/[ADP] ratio, ([ATP] + [ADP] + [AMP]), [ATP]/([ATP] + [ADP] + [AMP]) and energy charge remained essentially constant until 72 h, despite periods of increased energy turnover. At 24 h there was a burst of glycogenolysis, and glycolysis indicated by increased lactate production, which coincided with formation of syncytium. Subsequently, there was no resynthesis nor further breakdown of glycogen. At 48 h, oxygen consumption temporarily increased substantially, without increased glycolysis, during functional differentiation of the syncytiotrophoblast. Glucose uptake was constant and largely from the basal (in vivo fetal facing) side. Lactate output into the basal fetal medium was twice as fast as that into the microvillous (maternal) medium, and oxygen uptake was also asymmetrical. The results show that before and after differentiation substantial relatively constant aerobic glycolysis occurs, but that during increased energy demand cytotrophoblast depends on both glycolytic and aerobic energy production whereas syncytiotrophoblast relies on aerobic metabolism.
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PMID:Energy metabolism and glycolysis in human placental trophoblast cells during differentiation. 913 Oct 49

We have studied the surface of native Valonia cellulose I microcrystals under propanol and waterby atomic force microscopy (AFM). Ultra-high-resolution images of the surface are presented, as well as lower resolution morphological observations of whole crystals. The pitch of 0.52 nm along the molecule due to the asymmetrical glucose unit and the intermolecular spacing of approximately 0.6 nm are clearly resolved in both imaging environments. The relationship between the crystalline bulk and the surface are discussed, with particular attention being paid to previous crystallographic studies. We also show that the glucose units along the cellulose chains are not topographically equivalent due to the twofold screw symmetry and accordingly present strong evidence of triclinic character by direct surface imaging, rather than by taking average measurements in reciprocal space. The crystallographic distinction between monoclinic and triclinic structure is a displacement of the cellulose chains by a quarter of the c axis period, resulting in either a stagger or a diagonal shifting, respectively, of the cellobiose unit along the chain axis by 0.26 nm. This structural identification (in real space) represents, as far as we are aware, the highest resolution AFM imaging of a biological specimen to date. This study opens up the future possibility of identifying the localized triclinic or monoclinic nature of the Valonia cellulose surface with AFM.
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PMID:High-Resolution Atomic Force Microscopy of Native Valonia Cellulose I Microcrystals 924 53

Myocardial glucose metabolism has been shown to be heterogeneous in patients with hypertrophic cardiomyopathy (HCM). We tested the hypothesis that myocardial glucose metabolism differs between patients with HCM and those with hypertensive heart disease (HHD) associated with asymmetrical septal hypertrophy. We studied 12 patients with HCM, 7 HHD patients associated with asymmetrical septal hypertrophy using 18F 2-deoxyglucose (FDG) and positron emission tomography. We calculated % FDG fractional uptake in the inter-ventricular septum and posterolateral wall. Heterogeneity of FDG uptake was evaluated by % interregional coefficient of variation of FDG fractional uptake in each wall segment. In both the interventricular septum and posterolateral wall, % FDG fractional uptake was not significantly different between the two groups. The % interregional coefficient of variation for both interventricular septum (10.6 +/- 1.6 vs. 4.1 +/- 0.5, p < 0.01) and posterolateral wall (5.9 +/- 0.7 vs. 3.8 +/- 0.5, p < 0.05) was significantly larger in patients with HCM than in HHD patients associated with asymmetrical septal hypertrophy. Echocardiography demonstrated that the degree of asymmetrical septal hypertrophy was similar between the two groups. These results suggest that myocardial glucose metabolism may be more heterogeneous in patients with HCM compared to HHD patients associated with asymmetrical septal hypertrophy, although the left ventricular shape is similar. The difference in the heterogeneity might have resulted from differences in the pathogeneses of the two diseases.
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PMID:Myocardial glucose metabolism is different between hypertrophic cardiomyopathy and hypertensive heart disease associated with asymmetrical septal hypertrophy. 926 31

Depressions of regional cerebral metabolism beyond the epileptogenic zone have been demonstrated in patients with intractable temporal lobe epilepsy. However, their clinical relevance, and the causes of prefrontal metabolic asymmetries are less well understood. We investigated 96 temporal lobe epilepsy patients by FDG-PET and neuropsychological assessment who had a corresponding unilateral temporal hypometabolism, left hemisphere speech dominance, full scale IQ of > 70 and no extratemporal lesion in MRIs. The regional glucose metabolism was determined in each patient in homologous regions including prefrontal cortex, and normalized to whole brain metabolism. Regional differences of > 10% were regarded as asymmetrical. Prefrontal metabolic asymmetries were more frequent in patients with left temporal lobe epilepsy (21 left, six right) and a history of secondarily generalized seizures. A multivariate analysis of variance revealed a main effect for prefrontal metabolic asymmetry on neuropsychological 'frontal lobe measures', including verbal and performance intelligence measures. Prefrontal metabolic asymmetry was not related to 'measures of episodic memory', presence of psychiatric symptoms or frontal interictal epileptiform discharges. We conclude that prefrontal metabolic asymmetry is associated with cognitive impairment. Patients with temporal lobe epilepsy of the left speech dominant hemisphere and a history of secondarily generalized seizures are at considerable risk of developing prefrontal metabolic asymmetry.
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PMID:Prefrontal asymmetric interictal glucose hypometabolism and cognitive impairment in patients with temporal lobe epilepsy. 944 82

A computer program was developed to allow easy derivation of steady-state velocity and binding equations for multireactant mechanisms including or without rapid equilibrium segments. Its usefulness is illustrated by deriving the rate equation of the most general sequential iso ordered ter ter mechanism of cotransport in which two Na+ ions bind first to the carrier and mirror symmetry is assumed. It is demonstrated that this mechanism cannot be easily reduced to a previously proposed six-state model of Na+-D-glucose cotransport, which also includes a number of implicit assumptions. In fact, the latter model may only be valid over a restricted range of Na+ concentrations or when assuming very strong positive cooperativity for Na+ binding to the glucose symporter within a rapid equilibrium segment. We thus propose an equivalent eight-state model in which the concept of positive cooperativity is best explained within the framework of a polymeric structure of the transport protein involving a minimum number of two transport-competent and identical subunits. This model also includes an obligatory slow isomerization step between the Na+ and glucose-binding sequences, the nature of which might reflect the presence of functionally asymmetrical subunits.
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PMID:Reduction of an eight-state mechanism of cotransport to a six-state model using a new computer program. 953 94


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