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Biomedical subjects

J A Winfield

Publications and source records attributed to J A Winfield.

32 records · Page 2Linked to original sources
PubMed1984

The warning leak in subarachnoid hemorrhage and the importance of its early diagnosis.

A 40-year-old man had a severe headache of sudden onset and progressive palsy of the third cranial nerve from a minor subarachnoid hemorrhage. Despite assessment by two primary care physicians the possibility of serious neurologic disease was not raised and the urgency of the situation not appreciated. Two weeks after the onset of the headache the patient was urgently admitted to hospital at the request of a neuro-ophthalmologist. Cerebral angiography revealed an aneurysm of the posterior communicating artery, which was surgically occluded with a clip. The patient had a satisfactory recovery, with almost complete return of nerve function by the time of discharge from hospital. Such "warning leaks" in subarachnoid hemorrhage are discussed, and a protocol for their assessment is recommended.

Adult↗
PubMed1979

Vestibular effects of electrical stimulation of the cochlea. Monitored in the awake primate.

The effect of electrical stimulation of the cochlea on vestibular response was monitored in six rhesus monkeys. Eye movements and single-unit activity from the vestibular portion of the eighth nerve, vestibular nuclei, reticular formation, and abducens nucleus were observed while electrical stimulation was delivered through an implanted cochlear prosthesis. In one animal of this series, neural activity from the inferior colliculus and cochlear nuclear complex was also recorded. Electrical stimulation elicited eye-movement responses in only one animal. In the animals from which single-unit activity was recorded, no positive vestibular effects were noted. In one animal of this study, responses were elicited from auditory structures by relatively low intensities of electrical stimulation.

Acoustic Stimulation↗
PubMed1976

Effect of early exposure to patterned sound on unit activity in rat inferior colliculus.

1. Young rats were exposed to one of two patterns of sounds for 5 h daily during the first 4 mo of life. The up pattern consisted of a tone swept from 6 to 9 kHz in 1 s alternated with a 1-s noise burst. The down pattern differed in that the sweeps were from 9 to 6 kHz. 2. A pattern evoked more spikes, on the average, from units in the inferior colliculus of rats exposed to that pattern than from units in animals exposed to the other pattern. 3. The exposure effect was most pronounced in the unit responses to the noise-burst segment within a pattern suggesting a long-lasting, malleable influence of the tone sweep which defined the pattern. Responses to pattern noise components were less for both exposed groups than for the unexposed controls, suggesting that inhibitory mechanisms were responsible for the pattern discrimination evident in the responses of the exposed unit population. 4. Unit responses in unexposed rats were somewhat more selective for the down pattern so that the resulting shift in response selectivity was relatively more apparent for exposure to the up pattern. 5. While control and down-exposed units generally responded more to both the tone sweep and noise burst in one pattern, a large proportion of the up-exposed unit population continued to favor the down over the up-swept tone, but responded more to the up-pattern noise bursts. This suggests that the unit responses to the noise bursts did not simply reflect prolonged responses to the tone sweeps. 6. No similar effects were seen for units from mothers similarly exposed to the same patterns.

Acoustic Stimulation↗
PubMedDate not supplied

A rare case of cerebellar glioblastoma multiforme in childhood: MR imaging.

Glioblastoma multiforme is a highly malignant brain neoplasm that is very rarely discovered in childhood but accounts for approximately 17% of intracranial tumors in the adult. Only approximately 25 children with glioblastoma multiforme in the cerebellum have been described in the literature. We report on a 4 1/2-year-old girl with this tumor in the cerebellar hemisphere and discuss the magnetic resonance imaging findings.

Brain↗
PubMedDate not supplied

Cerebral venous thrombosis. Demonstration with magnetic resonance angiography.

Three patients with cerebral venous thrombosis (CVT) were imaged with magnetic resonance angiography (MRA). Initial spin-echo magnetic resonance (MR) demonstrated acute or subacute thrombosis in all patients. The presence of thrombosis was confirmed with MRA. Repeat MRA in the three patients revealed partial recanalization in one and almost complete recanalization in two patients. The etiology of CVT is reviewed, and the advantages of MRA are compared with conventional MR imaging and computed tomography in the evaluation of CVT.

Adult↗
PubMedDate not supplied

Salmonella osteomyelitis with epidural abscess. A case report with review of osteomyelitis in children with sickle cell anemia.

Neurologic complications of sickle cell anemia are most commonly ischemic strokes secondary to sludging in cerebral arterioles. We, therefore, report a case of progressive paraparesis in a child with sickle cell anemia which was initially thought to be secondary to a spinal cord ischemic event. Further diagnostics demonstrated that the neurologic deficits were secondary to salmonella osteomyelitis and an epidural abscess, compressing the upper thoracic spinal cord at the T6 level. The diagnostic and radiological features which help to distinguish between bone infarct and osteomyelitis, both responsible for bone pain in sickle cell patients, are also presented. In particular, Tc-sulfur colloid bone marrow imaging is the most helpful test for distinguishing between these similarly presenting clinical entities, as early as 48 h after bone pain develops.

Abscess↗
PubMedDate not supplied

Fourth ventricular entrapment caused by rostrocaudal herniation following shunt malfunction.

The subacute development of isolated fourth ventricle (IFV) is a recognized complication following shunting of the lateral ventricles for congenital and acquired hydrocephalus. We present an unusual case of acute IFV in a clinical setting which has not previously been described. Subsequent to rostrocaudal herniation caused by an obstructed frontally placed ventricular catheter, IFV developed in our patient 24 h following shunt revision, necessitating placement of an additional fourth ventricle shunt system. No signs of intraventricular hemorrhage or cerebrospinal fluid (CSF) infection were detected at the time of shunt revision and there was no documentation of similar events in the perinatal history. Dependent upon the actual underlying etiology of this child's hydrocephalus, we hypothesize that two mechanisms may have accounted for this unusual and precipitous development of IFV. Following rostrocaudal herniation and caudal shift of the brainstem, progressive edema in the pons developed. If communicating hydrocephalus was the primary etiology, then midbrain edema occluded the aqueduct of Sylvius, preventing retrograde flow of CSF to the shunt. A distinctly different mechanism for acute IFV must be invoked if aqueductal stenosis was the preexisting cause for congenital hydrocephalus. Following herniation, brainstem displacement and edema resulted in obliteration of the lateral pontine and ambient cisterns, preventing the normal rostral migration of CSF around and over the mesencephalon. Cerebellar tonsillar herniation with impaction of the tonsils into the foramen magnum may have also contributed to obstruction of fourth ventricular outflow in both settings. This unusual case of acute onset IFV is presented in detail. The underlying etiologies and clinical settings in which IFV may develop is reviewed as well.(ABSTRACT TRUNCATED AT 250 WORDS)

Brain Edema↗