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Biomedical subjects

I L Kwee

Publications and source records attributed to I L Kwee.

63 records · Page 4Linked to original sources
PubMed1984

Sustained upgaze in coma.

Sustained upgaze is a rare phenomenon that is observed primarily in those patients with coma secondary to cardiac arrest or prolonged hypotension. Because of "selective vulnerability" of the brain, cardiac arrest or prolonged hypotension may produce both cerebral and cerebellar cortical damage sparing the brain stem vestibulo-ocular reflex (VOR) pathways. This selective damage may be responsible for the generation of sustained upgaze. The VORs receive their selective inhibition from the cerebellar flocculus. This inhibition is exerted on only one of the two VOR pathways converging on each extra-ocular muscle, so that total disinhibition of the VOR pathway activities will result in a tonic upward bias. The underlying neuronal mechanism of sustained upgaze appears to be due to total floccular disinhibition resulting in upward drift produced by the biased VOR and the lack of correcting saccades due to cerebral dysfunction releasing the brain stem ocular motor systems from their control.

Cerebellar Cortex↗
PubMed1984

Epileptic Kluver-Bucy syndrome: case report.

The Kluver-Bucy syndrome (KBS) consists of prominent oral tendencies, emotional blunting, altered dietary habits, hypersexuality, and visual and auditory agnosia. It was first produced experimentally in monkeys; subsequently, many human cases have been reported. The syndrome results from bilateral temporal lobe damage, and is mainly observed in conditions which tend to produce such damage, such as herpes encephalitis, Pick disease, and head injury. A case of KBS associated with psychomotor status epilepticus is reported.

Agnosia↗
PubMed1983

Triple fossa metastasis of prostate cancer.

The radiological appearance of prostate cancer metastasis to the central nervous system often mimics meningioma. The bony change of prostate cancer metastasis resembles the hyperostosis of meningioma because of its blastic rather than lytic nature. On computed tomographic (CT) scan, like meningioma, prostate cancer metastasis enhances homogeneously after the infusion of contrast material. Triple fossa (middle, temporal, and orbital fossae) involvement by a solitary mass without bony destruction is thought to be highly specific for meningiomas. We report a case demonstrating the CT findings typical for a triple fossa meningioma caused by prostate cancer metastasis.

Adenocarcinoma↗
PubMed1983

Theophylline-induced seizures: clinical and pathophysiologic aspects.

The clinical features and management of theophylline-induced seizures are not well appreciated in spite of their unique aspects. These seizures tend to occur in neurologically intact patients and leave no or only minor neurologic sequelae if controlled early. They begin with focal motor seizures with or without secondary generalization and are followed by stupor or coma. They are responsive only to adjustment of theophylline dosage. Should the motor phenomenon persist, it takes the form of epilepsia partialis continua. Extensive workup for a structural brain lesion may be unrewarding. The electroencephalogram typically shows periodic lateralized epileptiform discharges, which may provide a diagnostic clue.

Aged↗
PubMed1982

Computed tomography of spinal cord atrophy.

Spinal cord atrophy takes on several different forms which correlate closely with specific clinical features. The majority of them, however, can be categorized into three distinct patterns, diffuse (transverse myelopathy), hemi- (Brown-Sequard syndrome), or anterior (anterior spinal artery syndrome) atrophy. Until recently, the differential diagnosis had been made solely on the neurological examination. We present three cases of spinal cord atrophy, one in each category. Spinal computed tomography with metrizamide appears to be a reliable supporting diagnostic method for spinal cord atrophy.

Atrophy↗
PubMed1982

Floccular inhibition of the vestibulo-ocular reflex in man.

The vestibulo-ocular reflex (VOR) plays a major role in ocular motility. Stimulation of each semicircular canal produces excitation of a specific extraocular muscle and inhibition of its antagonist in each eye. Floccular inhibition of the VOR has been extensively studied in the rabbit. Inhibitory projections from floccular Purkinje cells reach the ipsilateral vestibular nucleus via the restiform body and selectively control certain VORs. We examined the ocular functions in a patient with a lateral lower pontine infarct that included the restiform body. The patient exhibited unilateral, selective disinhibition of the VOR manifested by disconjugate upward rotatory drift of the eyes at the end of lateral eye movement towards the side of the lesion. He had marked directional preponderance on caloric testing. The same underlying mechanism which produced the biased VOR also appeared to affect target position determination in fast eye movements, resulting in lateropulsion of saccades and asymmetric OKNs. This is the first clinical case supporting the theory of selective cerebellar inhibition of the VOR.

Animals↗
PubMedDate not supplied

19F 2-FDG NMR imaging of the brain in rat.

Images of the rat head reflecting glucose utilization were obtained using 2-fluoro-2-deoxy-D-glucose (2-FDG) and 19F nuclear magnetic resonance (NMR) imaging. Spatial heterogeneity of glucose utilization in the rat head was clearly demonstrated showing significantly higher glucose utilization in the brain as compared to the surrounding tissues. Although the potential adverse effects of the high doses of 2-FDG (400 mg/kg) needed to perform the study preclude immediate application of this technique to clinical quantitative glucose utilization studies, the present study shows potential for future development of glucose utilization imaging by NMR.

Animals↗
PubMedDate not supplied

One-dimensional chemical shift imaging of fluorinated neuroleptics in rat brain in vivo by 19F NMR rotating frame zeugmatography.

One-dimensional chemical shift imaging reflecting local tissue contents of the fluorinated neuroleptics fluphenazine and trifluoperazine in rat brain was obtained noninvasively in vivo using one-dimensional 19-fluorine (19F) nuclear magnetic resonance (NMR) rotating frame zeugmatography. Activities of these fluorinated neuroleptics showed a differential distribution in the brain, maximal in the deep structures presumably within the basal ganglia. An additional resonance of an unidentified fluorinated metabolite was localized to the subcutaneous tissue. The present data indicate the feasibility of chemical shift imaging of fluorinated neuroleptics using a high field NMR system and the potential for future development of neurotransmitter imaging by NMR.

Animals↗