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Query: UMLS:C0011570 (depression)
 172,036 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We report a case of spinal subdural haematoma with neurological deficit in a 36-yr-old woman following Caesarean section for severe preeclampsia and placental abruption. She had been taking chronic trifluoperazine treatment for depression. Her activated partial thromboplastin time (aPTT) was 49 sec (normal = 26-36) but all other tests of coagulation were normal. Epidural anaesthesia was attempted but, despite a negative test dose, injection of local anaesthetic resulted in a generalized seizure and general anaesthesia was induced. Seventy-two hours after delivery, she was found to have bilateral leg weakness, urinary incontinence, absent rectal sphincter tone and asymmetrical leg reflexes. The diagnosis of spinal haematoma was confirmed by magnetic resonance imaging. She underwent emergency laminectomy and made a full neurological recovery.
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PMID:Spinal subdural haematoma in a parturient after attempted epidural anaesthesia. 826 79

1. We assessed the effects of specific brain hypoxia on the control of inspiratory and expiratory muscle electromyographic (EMG) activities in response to specific carotid body hypoxia in seven awake goats. We used an isolated carotid body perfusion technique that permitted specific, physiological, steady-state stimulation of the carotid bodies or maintenance of normoxia and normocapnia at the carotid bodies while varying the level of systemic, and therefore, brain oxygenation. 2. Isolated brain normocapnic hypoxia of up to 1.5 h duration increased inspired minute ventilation (VI) by means of increases in both tidal volume (VT) and respiratory frequency (fR). Electromyographic activities of both inspiratory and expiratory muscles were augmented as well. These responses were similar to those produced by low levels of whole-body normoxic hypercapnia. We conclude that moderate levels of brain hypoxia (Pa,O2 approximately 40 mmHg) in awake goats caused a net stimulation of ventilatory motor output. 3. Hypoxic stimulation of the carotid bodies alone caused comparable increases in VT and fR, and EMG augmentation of both inspiratory and expiratory muscles whether the brain was hypoxic or normoxic. These responses were quite similar to those obtained over a wide range of whole-body normoxic hypercapnia. We conclude that the integration of carotid body afferent information is not affected by moderate brain hypoxia in awake goats. 4. We found no evidence for an asymmetrical recruitment pattern of inspiratory vs. expiratory muscles in response to carotid body hypoxia or in response to brain hypoxia alone. 5. Our data support the concept that moderate brain hypoxia results in a net stimulation of respiratory motor output. These findings question the significance of 'central hypoxic depression' to the regulation of breathing under physiological levels of hypoxaemia in the awake animal.
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PMID:Effects of specific carotid body and brain hypoxia on respiratory muscle control in the awake goat. 848 10

The spatiotemporal progression of cortical spreading depression was investigated by imaging of activity-dependent intrinsic optical signals in rat sensorimotor cortex. In contrast to the traditional conception of a uniformly propagating event, the evolution of the spreading depression was characterized by an asymmetrical propagating wavefront and a non-uniform dispersion of optical signals behind the wavefront. As these optical signals are a reflection of underlying molecular and metabolic processes, the imaging approach to spreading depression might constitute a useful technique for investigating the functional organization as well the pathophysiology of the cerebral cortex.
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PMID:Characterization of cortical spreading depression by imaging of intrinsic optical signals. 898 44

The physicochemical properties of water enable it to act as a solvent for electrolytes, and to influence the molecular configuration and hence the function--enzymatic in particular--of polypeptide chains in biological systems. The association of water with electrolytes determines the osmotic regulation of cell volume and allows the establishment of the transmembrane ion concentration gradients that underlie nerve excitation and impulse conduction. Fluid in the central nervous system is distributed in the intracellular and extracellular spaces (ICS, ECS) of the brain parenchyma, the cerebrospinal fluid, and the vascular compartment--the brain capillaries and small arteries and veins. Regulated exchange of fluid between these various compartments occurs at the blood-brain barrier (BBB), and at the ventricular ependyma and choroid plexus, and, on the brain surface, at the pia mater. The normal BBB is relatively permeable to water, but considerably less so to ions, including the principal electrolytes Brain fluid regulation takes place within the context of systemic fluid volume control, which depends on the mutual interaction of osmo-, volume-, and pressure-receptors in the hypothalamus, heart and kidney, hormones such as vasopressin, renin-angiotensin, aldosterone, atriopeptins, and digitalis-like immunoreactive substance, and their respective sites of action. Evidence for specific transport capabilities of the cerebral capillary endothelium, for example high Na+K(+)-ATPase activity and the presence at the abluminal surface of a Na(+)--H+ antiporter, suggests that cerebral microvessels play a more active part in brain volume regulation and ion homoeostasis than do capillaries in other vascular beds. The normal brain ECS amounts to 12-19% of brain volume, and is markedly reduced in anoxia, ischaemia, metabolic poisoning, spreading depression, and conventional procedures for histological fixation. The asymmetrical distributions of Na+ K+ and Ca2+ between ICS and ECS underlie the roles of these cations in nerve excitation and conduction, and in signal transduction. The relatively large volume of the CSF, and extensive diffusional exchange of many substances between brain ECS and CSF, augment the ion-homeostasing capacity of the ECS. The choroid plexus, in addition to secreting CSF principally by biochemical mechanisms (there is an additional small component from the extracellular fluid), actively transports some substances from the blood (e.g. nucleotides and ascorbic acid), and actively removes others from the CSF. In contrast with CSF secretion, CSF reabsorption is principally a biomechanical process, passively dependent on the CSF-dural sinus pressure gradient. Pathological increases in intracranial water content imply development of an intracranial mass lesion. The additional water may be distributed diffusely within the brain parenchyma as brain oedema, as a cyst, or as increase in ventricular volume due to hydrocephalus. Brain oedema is classified on the basis of pathophysiology into four categories, vasogenic, cytotoxic, osmotic and hydrostatic. The clinical conditions in which brain oedema presents the greatest problems are tumour, ischaemia, and head injury. Peritumoural oedema is predominantly vasogenic and related to BBB dysfunction. Ischaemic oedema is initially cytotoxic, with a shift of Na+ and CI- ions from ECS to ICS, followed by osmotically obliged water, this shift can be detected by diffusion-weighted MRI. Later in the evolution of an ischaemic lesion the oedema becomes vasogenic, with disruption of the BBB. Recent imaging studies in patients with head injury suggest that the development of traumatic brain oedema may follow a biphasic time course similar to that of ischaemic oedema. Hydrocephalus is associated in the great majority of cases with an obstruction to the circulation or drainage of CSF, or, occasionally, with overproduction of CSF by a choroid plexus papilloma. In either case, the consequence is a ris
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PMID:The normal and pathological physiology of brain water. 907 71

Dispositional tendencies toward appetitive motivation have been hypothesized to be related to the development of psychopathology. Moreover, decreased left-frontal cortical activity has been reported in depression and has been related to low-trait positive affect and high-trait negative affect. The present study tested the hypothesis that relatively greater left- than right-frontal cortical activity would be related to heightened approach-related dispositional tendencies. Resting frontal cortical asymmetrical activity, as measured by electroencephalographic activity in the alpha band, was examined in relation to the motivational response tendencies of a behavioral activation system (BAS) and a behavioral inhibition system (BIS), as measured by C. S. Carver and T. L. White's (1994) BIS-BAS self-report questionnaire. Results supported the hypothesis.
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PMID:Behavioral activation sensitivity and resting frontal EEG asymmetry: covariation of putative indicators related to risk for mood disorders. 910 28

Hornyhead turbot, Pleuronichthys verticalis (Pleuronectiformes: Pleuronectidae), are morphologically asymmetrical teleosts with substantial bilateral asymmetry in the neurocranium, suspensorium and anterior jaws. In order to quantify the kinematics of prey capture and to test for functional bilateral asymmetries, four individuals of this species were video-taped feeding using a high-speed video system at 200 fields s-1. Frame-by-frame analysis revealed several features not commonly found in prey capture behavior of previously studied ray-finned fishes. These features include (1) extreme lateral compression of the suspensorium and opercular series prior to mouth opening, indicating the consistent presence of a preparatory phase during feeding, (2) apparent dissociation of hyoid retraction and lower jaw depression, (3) prolonged hyoid retraction throughout much of the feeding cycle, and (4) concomitant dorsal rotation of the neurocranium and closing of the jaws. P. verticalis also demonstrate a significant degree of functional bilateral asymmetry during prey capture. When approaching prey, fish flex their heads towards the ocular (anatomically the right) side of the body. During prey capture, their jaws bend out of the midline towards the blind (left) side. Comparisons of the displacement and timing for movements of homologous anatomical features on the ocular and blind sides of the head reveal that maximum gape is always larger on the blind side of the head than on the ocular side. In contrast, other kinematic variables measured are similar on both sides of the head. These results suggest that P. verticalis possess unique functional features of prey capture behavior and that morphological bilateral asymmetry of the head and jaws is associated with, and perhaps causally related to, the functional bilateral asymmetry present during feeding.
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PMID:Kinematics of prey capture in a flatfish, Pleuronichthys verticalis 931 16

In this paper, thermal avoidance in tethered flying locusts is described for the first time. Changes in body posture examined using high-speed cinematography revealed that the animals responded to a laterally positioned heat source with contralaterally directed abdomen and hindleg ruddering, behavioural patterns resembling manoeuvres observed in collision avoidance and in response to auditory signals. The analysis also showed that, during stimulation, left and right forewing depression became asymmetrical during the downstroke but remained symmetrical during the upstroke. Hindwing depression and elevation remained symmetrical during stimulus presentations. Electromyographic recordings from the left and right first basalar muscles (M97; forewing depressors) showed that contralateral depressor muscle activity was advanced by 10­12 ms relative to that on the stimulated side. There was also an increase in burst duration on the contralaterally stimulated side and an increase in wingbeat frequency of approximately 3 Hz. Ablation experiments showed that removal of the antennal flagella, which are the site of previously described thermoreceptors, did not abolish thermal avoidance manoeuvres. We conclude that thermal avoidance is triggered by an infrared sensitivity that is not mediated by the compound eyes, the ocelli or the antennal flagella.
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PMID:Thermal avoidance during flight in the locust Locusta migratoria 931 76

The kinematics of prey capture in two bilaterally asymmetrical pleuronectiform flatfish species (Pleuronichthys verticalis and Xystreurys liolepis) and two symmetrical percomorph species (Lepomis macrochirus, a centrarchid, and Cheilinus digrammus, a labrid) were compared to test the hypothesis that flatfish have distinct prey-capture kinematics from those quantified for other percomorph fishes. Size-matched individuals of both flatfish species were video-taped feeding using a high-speed video system. Cephalic displacement and timing variables were quantified and compared with data from similarly sized L. macrochirus and C. digrammus previously collected by other researchers using similar experimental methodology. Nested multivariate analyses of variance indicated that there was no significant difference in prey-capture kinematics between flatfish and non-flatfish taxa, but that prey-capture kinematics did differ among the four taxa. Multiple nested analyses of variance revealed that the taxa differed in 7 of 11 kinematic variables. Post-hoc tests and comparisons with other fish taxa suggest that individuals of P. verticalis possess an unusual combination of prey-capture kinematics including large hyoid depression, large neurocranial rotation, large upper jaw protrusion and small gape. Previous research has suggested that this combination of traits is associated with suction-based prey capture. Correspondingly, the ram­suction index calculated for P. verticalis is more negative (indicating a greater use of suction) than that calculated for the other taxa. When homologous kinematic variables are compared across these four taxa, flatfish do not appear to have similar prey-capture kinematics. However, both flatfish species are distinct from the two symmetrical percomorph species in their asymmetrical jaw movements.
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PMID:Do flatfish feed like other fishes? A comparative study of percomorph prey-capture kinematics. 934 70

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

Studies using single photon emission computed tomography (SPECT) have found low cerebral blood flow (CBF) in frontal and parietal cortices in patients with chronic opiate dependence. In the present study, SPECT with 99mTc-HMPAO as tracer was used to compare 27 detoxified opiate addicts with nine healthy control subjects. All the subjects were evaluated with clinical psychiatric (DSM-IV), psychometric and neuropsychological measures. Compared with normal control subjects, the addicts showed a non-significant reduction of whole brain perfusion values. Significant hypoperfusion in the right frontal and left temporal lobes was found in addicts with comorbid depression, and a significant decrease in CBF in the right frontal lobe was observed in those with antisocial tendencies. A significant negative correlation emerged between Depression subscale scores on the Minnesota Multiphasic Personality Inventory and left temporal CBF in the patients. No significant correlations were found, however, between measures of cognition and CBF in opiate addicts. The asymmetrical findings in CBF that characterized the addicts relative to normal control subjects may be more closely related to mood and behavioral traits than to substance abuse, per se.
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PMID:Regional cerebral blood flow and comorbid diagnosis in abstinent opioid addicts. 981 37


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