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Biomedical subjects

B Remler

Publications and source records attributed to B Remler.

13 recordsLinked to original sources
PubMed1998

Global cerebral blood flow, blood volume, and oxygen metabolism in patients with migraine headache.

OBJECTIVE: Migraine headaches with and without aura are representative of vascular headache states traditionally thought to be mediated by alterations in vascular tone. Validation of this theory has been hampered in part by technical difficulties inherent in the measurement of cerebral blood flow (CBF). The purpose of this study was to compare CBF measured during migraine and migraine-free states using PET. METHODS: Patients with a minimum of one migraine headache without aura per month (International Headache Society [IHS] criteria) underwent measurement of CBF, cerebral blood volume (CBV), oxygen extraction, and metabolism during an episode of spontaneous migraine headache. Imaging was repeated during a migraine-free period of at least 48 hours. PET radiotracers used were: CBF, H(2)15O; CBV, C15O; oxygen metabolism, 15O2. RESULTS: In nine patients (seven female and two male), global CBF (mL/min/100 g [SD]) was measured as 52.70 (6.9) during migraine and 59.65 (10.6) in the migraine-free state; p=0.028. CBV (mL/100 g [SD]) was 3.6 (0.43) during the symptomatic state and 3.8 (0.55) after the migraine; p=0.047. Oxygen metabolism (mL/min/100 g [SD]) was 3.68 (0.9) during migraine and 3.38 (1.02) without headache; p=0.211. The oxygen extraction ratio was 0.48 (0.15) and 0.41 (0.12) during migraine and migraine-free states, respectively; p=0.132. CONCLUSIONS: In patients experiencing migraine without aura, CBF and CBV are reduced during the headache phase. Cerebral oxygen metabolism and oxygen extraction are not significantly affected.

Adolescent↗
PubMed1997

Benign paroxysmal positioning vertigo: classic descriptions, origins of the provocative positioning technique, and conceptual developments.

The original description of benign paroxysmal positioning vertigo (BPPV) has been variously attributed to Bárány, Adler, and others. In addition, the proper eponymic designation for the provocative positioning test used to diagnose BPPV has been unclear, because authors use a variety of different terms, including Bárány, Nylén-Bárány, Nylén, Hallpike, Hallpike-Dix, and Dix-Hallpike to refer to the procedure in current use. Based on a review of the extant medical literature, Bárány was the first to describe the condition in detail, and Dix and Hallpike were the first to clearly describe both the currently used provocative positioning technique and the essential clinical manifestations of benign paroxysmal positioning vertigo elicited by that technique. Nevertheless, despite their important contributions, neither Bárány nor Dix and Hallpike understood the pathophysiology of BPPV nor did they appreciate that the positioning techniques they used actually demonstrated pathology in the semicircular canals rather than the utricle. The modern understanding of the pathophysiology of BPPV began with Schuknecht's proposal that the dysfunction resulted from the gravity-dependent movement of loose or fixed dense material within the posterior semicircular canal ("cupulolithiasis"). Although Schuknecht's formulations were not consistent with all clinical features of the disease, they led to the modern "canalolithiasis theory" and highly effective canalith repositioning or "liberatory" maneuvers for BPPV.

History, 20th Century↗
PubMed1996

Opsoclonus.

Opsoclonus is a rare disorder of the saccadic system, in which fixation is continuously interrupted by multivectorial, back-to-back saccades that at times can be seen only with an ophthalmoscope. To diagnose it reliably, eye movement recording is required. Opsoclonus may be a harbinger of an occult malignancy, though many cases are postinfectious, toxic-metabolic or idiopathic. The underlying malignancy is usually neural crest tumors in children and lung, breast, or gynecologic cancer in adults. Opsoclonus can be accompanied by myoclonus and ataxia. Concurrent appearance of oscillations affecting eyes and limbs suggests a common brainstem generator. Dysfunction of the glycinergic omnipause neurons in the nucleus raphe interpositus has been proposed. Autoantibodies against neural epitopes shared with a tumor are implicated in the pathogenesis of opsoclonus in paraneoplastic cases. Because of the association with malignancies, full oncological work-up is indicated in every case. Coexisting opsoclonus carries a relatively good prognosis for the cancer; however, the neurologic disability may remain even if the tumor has been arrested. New, potentially effective immunoadsorption therapy for opsoclonus is currently under investigation.

Adult↗
PubMed1990

Balint's syndrome in Alzheimer's disease: visuospatial functions.

A subgroup of patients with Alzheimer's disease (AD) developed Balint's syndrome, an uncommon and incompletely understood disorder of visuospatial processing. We characterized the visuospatial features of three AD patients with Balint's syndrome and compared them to three comparably demented AD patients without this syndrome. On visuospatial tasks, the Balint patients were unable to integrate visual stimuli over space. On contrast sensitivity testing, the Balint patients had significantly decreased contrast sensitivities for low spatial frequency gratings (0.5, 1.0 and 2.0 cpd) alternated at 7.5 Hz. Furthermore, the Balint patients had left visual field attentional deficits and normal hemifield P100 visual evoked potentials. In AD, Balint's syndrome involved decreased sensitivity to low spatial frequencies necessary for global visuospatial analysis, a disturbance suggesting damage to the magnocellular visual system in the occipitoparietal association cortex and, possibly, in the optic nerves.

Aged↗
PubMed1990

Disorders of the visual system in Alzheimer's disease.

Alzheimer's disease (AD) is associated with disturbances in basic visual, complex visual, and oculomotor functions. The broad range of visual system disorders in AD may result from the concentration of neuropathology in visual association cortex and optic nerves in this disease. AD patients and their caregivers frequently report visuospatial difficulties in these patients. Examination of the visual system in AD may reveal visual field deficits, prolonged visual evoked potentials, depressed contrast sensitivities, and abnormal eye movement recordings. Complex visual disturbances include constructional and visuoperceptual abnormalities, spatial agnosia and Balint's syndrome, environmental disorientation, visual agnosia, facial identification problems, and visual hallucinations. The purpose of this article is to review the spectrum of visual system disturbances found in AD and, in particular, to describe the methods used to screen for complex visual abnormalities in these patients.

Alzheimer Disease↗
PubMed1988

[New findings in Oguchi disease].

The authors report on clinical and electrophysiological studies of a patient with Type I Oguchi's disease. Numerous small pigmentations of the retinal pigment epithelium (RPE) causing focal disruption of the Oguchi reflex were observed, a phenomenon which has not previously been reported. Consistent with reports of pathologic changes in the RPE, an abnormal electro-oculogram (EOG) was recorded in this patient. On the basis of this information, the pigmentations were interpreted as dysplastic changes.

Adolescent↗
PubMed1986

[Pattern ERG in X-chromosome juvenile retinoschisis].

Typical electroretinographic findings in x-chromosomal juvenile retinoschisis are a normal a-wave and a reduced b-wave suggesting that the primary defect is located at the level of the bipolar cell layer whereas deeper retinal structures are not basically affected. The marked amplitude reduction in the pattern-ERG suggests to look for the origin of response in the inner retinal layer or in subsequent structures.

Child↗
PubMed1984

[Inflammatory and regressive changes of the posterior surface of the cornea].

A 52-year-old woman contracted a serious influenza; three weeks later a dropshaped patch, whitish-yellow in color and deeply vascularized, was seen on the posterior upper surface of the cornea of one eye. It was accompanied by an anterior uveitis. The Tyndall phenomenon was positive. The sensibility of the upper quadrants of the cornea was reduced, temporally to 1.84 g/mm2, nasally to 3.20 g/mm2. Central vision was approx. 0.03. The condition was treated locally with steroid eye drops and generally with Diclofenac 2 X 50 mg. The infiltration became clearer as a result and vision increased to 0.8. Further examinations over a period of 2-1/2 years revealed crystal-like deposits and fiberglass-like structures. The erythrocyte sedimentation rate remained elevated. Since the etiology of these changes is still unknown, the authors suggest the purely descriptive term 'deep parenchymatous keratitis'. It would seem likely that this is a herpetic condition, especially in view of the decreased sensibility of the upper quadrants of the cornea.

Cornea↗
PubMedDate not supplied

Phenytoin-induced seizures: a paradoxical effect at toxic concentrations in epileptic patients.

We examined the incompletely defined convulsant action of phenytoin (PHT) at toxic concentrations in humans. A retrospective chart review (1979-1985) yielded 96 cases (90 patients), meeting both clinical and laboratory criteria for PHT intoxication. Seven patients, all with epilepsy, had one or more seizures while toxic. However, in only two patients (2.1%) with serum concentrations of 93.2 and 69.7 micrograms/ml was a causal relationship deemed highly probable. Seizures did not occur in most toxic epileptic patients with total serum PHT concentrations as high as 85.1 micrograms/ml or in any of the nonepileptic patients with concentrations as high as 64.2 micrograms/ml. The lack of convulsant action of PHT in these patients suggests that seizure risk may be multifactorial and also that PHT is a weak convulsant. We conclude that PHT at very high concentrations can rarely exacerbate seizures or even precipitate generalized status in some epileptic patients, a paradoxical effect.

Adolescent↗
PubMedDate not supplied

Antiepileptic drug intoxication: factors and their significance.

A retrospective chart review (1979-1985) was performed to identify probable causes of intoxication with antiepileptic drugs (AEDs). We identified 141 patients meeting clinical and laboratory criteria for intoxication and 17 with clinical signs but with serum concentrations within the therapeutic range. The majority were epileptic patients; almost half were treated with monotherapy, most with phenytoin (PHT). The causes of intoxication in the epileptic patients were iatrogenic (41%), inappropriate dose self-adjustment (34%), suicide attempt (18%), inappropriate caretaker dose adjustment (9%), accidental ingestion (8%), unrecognized drug interaction (6%), and association with intercurrent illness (2%). Twenty-two patients had more than one probable cause of intoxication. In nonepileptic patients the causes were suicide attempt (50%), accidental ingestion (27%), and iatrogenic (23%). Most patients had signs of ocularmotor and vestibulocerebellar dysfunction. Rarely described manifestations of intoxication, such as seizures or choreoathethosis, were observed in a few patients. The average hospital stay was 6.9 days; there was no mortality, and all patients recovered fully. We conclude that AED intoxication is a major but preventable cause of morbidity and that suicide attempts are an important and underrecognized contributor in both epileptic and non-epileptic patients.

Accidents↗
PubMedDate not supplied

Assessment of the effects of ciprofloxacin and nalidixic acid on cerebral blood flow and metabolism in healthy subjects by positron emission tomography.

STUDY OBJECTIVES: The mechanism by which the fluorinated quinolones produce central nervous system effects is unknown. Using positron emission tomography (PET), we evaluated the effects of two quinolones on brain blood flow as well as on oxygen and glucose metabolism. These determinations were done in conjunction with ophthalmologic and neuro-ophthalmologic testing. DESIGN: Randomized, double-blind, placebo-controlled, 7-day course of ciprofloxacin 750 mg (C750) or 500 mg (C500) every 12 hours, or nalidixic acid (NA) 1 g every 6 hours. POPULATION: Twenty-four healthy male volunteers, six in each treatment arm. RESULTS: [table: see text] CONCLUSIONS: Compared with baseline values, NA significantly reduced brain glucose uptake, whereas C500, C750, and placebo produced no detectable effect. No compound significantly altered brain blood flow or oxygen metabolism compared with baseline or other treatments. No significant effect on electroretinographic, electro-oculographic, or other neuro-ophthalmologic tests was observed.

Adolescent↗