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Biomedical subjects

J K Morgan

Publications and source records attributed to J K Morgan.

16 recordsLinked to original sources
PubMed1996

Temporal lobe arteriovenous malformations: surgical management and outcome.

BACKGROUND: Temporal lobe arteriovenous malformations (AVMs) represent a subgroup of intracranial AVMs with particular characteristics and management issues. METHODS: We performed a retrospective analysis of 24 consecutive patients with temporal lobe AVMs treated with surgical excision. Factors such as location, size, arterial feeders, venous drainage, and clinical follow-up were recorded for each. Results were compared with those of 132 patients with nontemporal lobe AVMs surgically treated over the same time period. RESULTS: Sixteen of the temporal AVMs were located in the convexity, six in the mesotemporal region, and two were predominantly intraventricular. The mode of presentation was seizure in 11 patients, hemorrhage in 7, headache in 4, and 2 were asymptomatic. Patients with convexity AVMs more commonly presented with seizures, whereas patients with mesotemporal or intraventricular AVMs were more likely to present with hemorrhage. One patient with subarachnoid hemorrhage from a basilar artery aneurysm died. Postoperatively, 2 patients (8.3%) had a new hemiparesis and dysphasia, 1 (4%) had a new dysphasia and hemianopsia, and 3 others (13%) were left with an isolated superior quadrant field deficit. Lasting surgical morbidity other than isolated field deficit was 13% for patients with temporal AVMs and 15% for those with nontemporal AVMs. CONCLUSIONS: Temporal lobe AVMs may be successfully resected using a direct microsurgical approach with limited morbidity and excellent prognosis for recovery. Most of the deficits relating to AVM hemorrhage and those of the immediate postoperative period improved significantly over the subsequent few months.

Adolescent↗
PubMed1994

Ophthalmoplegia with bilateral ptosis secondary to midbrain hemorrhage. A case with clinical and radiologic correlation.

A 65-year-old white female presented with the sudden onset of headaches, bilateral ptosis, and complete ophthalmoplegia. Other than a mild decrease in mental status, she was neurologically intact. Magnetic resonance imaging (MRI) and computed tomography (CT) examinations showed a midline hemorrhage extending from the caudal diencephalon to the pontomesencephalic junction affecting the oculomotor complex, the medial longitudinal fasciculus (MLF), and the rostral parapontine reticular formation (PPRF). Ischemic changes were also noted in the midline pontine tegmentum possibly affecting root fibers from the abducens nuclei. Angiography was negative for a vascular anomaly. The radiologic findings are correlated with current models of oculomotor organization to provide an explanation for this patient's unique clinical presentation.

Aged↗
PubMed1992

Neuropeptide Y in the primate model of subarachnoid hemorrhage.

The cause of cerebral vasospasm after subarachnoid hemorrhage (SAH) remains unknown. Recently, an association between the potent vasoconstricting peptide, neuropeptide Y, and delayed cerebral vasospasm after SAH has been postulated. This was based on the findings of increased neuropeptide Y levels in the cerebrospinal fluid (CSF) and plasma after SAH in animals and humans. For this study, the primate model of SAH was used to assess the possible role of neuropeptide Y in delayed vasospasm after SAH. Fifteen cynomolgus monkeys underwent placement of a clot of either whole blood or red blood cells in the subarachnoid space around the middle cerebral artery (MCA). Sequential arteriography for assessment of MCA diameter and sampling of blood and CSF for neuropeptide Y were performed: before SAH (Day 0); 7 days after SAH, when signs of delayed cerebral vasospasm peak in this model and in humans; 12 days after SAH; and 28 days after SAH. Subarachnoid hemorrhage did not evoke changes in CSF or plasma levels of neuropeptide Y. Nine monkeys had arteriographic evidence of vasospasm on Day 7, but no change in neuropeptide Y levels occurred in plasma or CSF. In addition, neuropeptide Y levels did not change, even after resolution of vasospasm on Day 12 or Day 28. Neuropeptide Y levels were substantially higher in CSF than in arterial plasma (p less than 0.003 at each interval). No correlation was found between neuropeptide Y levels in CSF and in plasma. These results do not confirm a relationship between neuropeptide Y levels in the CSF or peripheral plasma and delayed cerebral vasospasm in SAH.

Analysis of Variance↗
PubMed1992

Is vasospasm related to proliferative arteriopathy?

Although proliferative arteriopathy has been postulated to play a role in the etiology of vasospasm after subarachnoid hemorrhage (SAH), histological and morphological studies examining cerebral vasospasm have produced conflicting results. To help settle this controversy, the authors used an in vivo label of cell division, bromodeoxycytidine, to assess cell proliferation in a primate model of SAH. Fifteen cynomolgus monkeys received a clot of either whole blood (11 animals) or red blood cells (four animals) placed around the right middle cerebral artery (MCA). On the day of surgery continuous intravenous infusion of bromodeoxycytidine was begun and continued until the animal was sacrificed immediately after arteriography on Day 7, 12, or 27 following surgery. Sections from the right and left MCA's were stained with a monoclonal antibody against bromodeoxcytidine, and labeled cells were counted. Arteriographic evidence of vasospasm occurred in nine monkeys on Day 7. On Day 12 and Day 27 no monkeys had persistent vasospasm. Placement of subarachnoid clot around the right MCA increased proliferative activity across all layers of the arterial wall. Most of the labeled cells were in the adventitia and the endothelium. Although there were more dividing cells in all layers of the right MCA than the left MCA (p < 0.01), the number of stained cells per section was limited (range 0.1 to 21.2, mean 8) and the occurrence of vasospasm was not associated with the number of dividing cells in the right MCA on Day 7, 12, 27, or for all days combined (p > 0.6). Cerebral vasospasm after SAH was not associated with the extent of proliferation of cells in the vessel wall, nor could the intensity of the limited proliferative changes have been responsible for narrowing of the vessel diameter.

Animals↗
PubMed1992

Tenosynovial giant-cell tumor of the cervical spine. Case report.

A case of tenosynovial giant-cell tumor affecting the cervical spine is reported. The lesion is seen primarily in the fingers, knee, or ankle, and there are no previous reports of it occurring in the spine. The histological and radiological features of this tumor are discussed along with a brief description of the disease entity.

Adult↗
PubMed1991

Central nervous system involvement in Von Hippel-Lindau disease.

Fifty individuals with Von Hippel-Lindau disease (VHL) were studied with gadolinium-enhanced magnetic resonance imaging (MRI) to determine the frequency and distribution of CNS lesions. The associated clinical features were also reviewed. Thirty-six (72%) of the 50 had 1 or more CNS tumors. The most frequently affected sites in the CNS excluding the retina were the cerebellum (52%), spinal cord (44%), and brainstem (18%). New regional predilections for the craniocervical junction and conus medullaris were demonstrated by this study. Forty-one percent of all VHL patients with CNS tumors were neurologically asymptomatic: cerebellar tumors (50%), spinal cord tumors (50%), and brainstem tumors (44%) were often without clinical signs or symptoms. Multiple lesions were common. The mean age of all VHL patients (34.5 years) was similar to the mean age of all CNS VHL patients (34.4 years), suggesting a lack of age association. CNS lesions commonly occurred in the 2nd decade of life. All patients at risk for VHL should be evaluated using gadolinium-enhanced MRI after 10 years of age, although ophthalmic examination should be initiated within the 1st 2 years of life. Enhanced MRI is particularly useful in the detection of CNS tumors in patients with the VHL gene.

Adolescent↗
PubMed1990

Thrombolytic therapy and posterior circulation extracranial-intracranial bypass for acute basilar artery thrombosis. Case report.

Basilar artery thrombosis has a very poor prognosis. A 56-year-old comatose man with acute basilar artery occlusion was successfully treated with local urokinase infusion which reopened the basilar artery and revealed a midbasilar stenotic plaque. This procedure was followed by a superficial temporal artery to superior cerebellar artery anastomosis for protection of the posterior circulation.

Acute Disease↗
PubMed1988

Venous angiomas: an underestimated cause of intracranial hemorrhage.

Cerebral venous angiomas are considered by many investigators as infrequent and incidental. Our experience, however, has been different. Since 1975, we have compiled a group of 21 patients with 23 venous angiomas. Nine patients (43%) presented with intracranial hemorrhage, and two in this group had recurrent hemorrhage. Surgical extirpation of the venous angioma was performed in all nine cases. An additional resection of a frontal venous angioma was performed in a woman with intractable seizures and headache. We experienced limited morbidity and no mortality. Although venous angiomas may be uncommon clinically, they have a significant potential for hemorrhage, and particularly, rehemorrhage if left untreated.

Adolescent↗
PubMed1987

Development of the basilar pons in the North American opossum: dendrogenesis and maturation of afferent and efferent connections.

The present study provides data on temporal factors that may play a role in the development of precerebellar-cerebellar circuits in the North American opossum. In this study the basilar pons and cerebellum are analyzed from birth, 12-13 days after conception, to approximately postnatal day (PD) 80 at which time the brainstem and cerebellum have a mature histological appearance. In Nissl preparations, the basilar pons was first seen at PD 7 as a small cluster of tightly packed cells. Analysis of Golgi impregnations revealed that dendritic growth occurred between PD 25-80. During this period, dendrites gradually increased in length and in the complexity of their branching pattern. Horseradish peroxidase (HRP) was placed into the cerebellar and cerebral cortices in order to examine the development of efferent and afferent projections of the basilar pons, respectively. Evidence for the growth of pontine axons into the cerebellum was first detected on PD 17. Neurons located dorsally within the basilar pons appear to be the first neurons retrogradely labeled with horseradish peroxidase. By PD 27 retrogradely labeled neurons are found throughout the basilar pons. Afferent fibers from the cerebral cortex are not seen within the neuropil of the nucleus until after PD 25 and by PD 29, they have greatly expanded their terminal fields. Degeneration techniques reveal that afferent fibers from the cerebellum arrive by PD 19 and increase in number until PD 30 when their adult distribution is achieved. These data suggest that the time of afferent arrival from the cerebral cortex and deep cerebellar nuclei is closely correlated in time with the initiation of dendritic maturation and the outgrowth of pontocerebellar axons. Afferent axons from the cerebral cortex and deep cerebellar nuclei reach the basilar pons and afferents from the basilar pons grow into the cerebellum when the dendrites of the respective target neurons are very immature. Thus, the time of axon arrival in these circuits may be an important factor in determining their synaptic location on individual neurons. The data derived from the present study is compared to those obtained in previous studies on the inferior olive. The results of this comparison provide evidence for a similar sequence of events, but a differential timetable for the development of specific connections within precerebellar-cerebellar circuits.

Afferent Pathways↗
PubMed1986

Team sports for the severely retarded: training a side-of-the-foot soccer pass using a maximum-to-minimum prompt reduction strategy.

A program to teach three severely retarded adults to use a side-of-the-foot soccer pass was evaluated. A 9-step stimulus-response chain was taught using forward chaining. In contrast to usual practice, intensive physical prompts were provided initially to teach each response component, then systematically faded. Approximately 20 lessons (trials) were presented in 20-min sessions. A multiple baseline across subjects design showed that the three trainees achieved the no-prompt criterion after 24, 29, and 22 sessions, respectively. Subanalyses indicated that successive response components were learned only after training was implemented. Follow-up data were obtained 57 and 276 days later in the training room and in a gymnasium; in both settings, criterion was achieved with fewer than three reinstructions.

Cues↗
PubMed1976

Infantile eczema: A long-term follow-up study.

A 15-17 year follow-up study was conducted on ninety-nine patients who had suffered from infantile eczema. The persistance of the eczema and the occurrence of related conditions were noted. The persistence of eczema was shown to be greater in those patients with a positive family history of eczema and in those who had developed asthma or hay-fever. An attempt was made to see if the persistence of eczema was affected by the position of the child in the family, and some factors provoking relapses were noted. The patients were also questioned with regard to their achievements in academic examinations, and to their social, artistic and sporting activities. The results showed a success rate in examinations not significantly higher than average. It was not possible to show if there is a particular type of atopic personality. There was no constant characteristic in social or artistic patterns. The group as a whole were normal at the milestones of early development, i.e. walking, talking and reading, and also normal with regard to weight and height.

Adolescent↗