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Biomedical subjects

R M Shuman

Publications and source records attributed to R M Shuman.

At least 19 recordsLinked to original sources
PubMed1995

The Chiari malformations: a constellation of anomalies.

The Chiari malformations form a group of abnormalities that are pathogenetically interrelated. The most important member of the group is the Chiari type II malformation, known as the Arnold-Chiari malformation. Its cardinal features are the myelomeningocele in the thoraco-lumbar spine, the venting of the intracranial cerebrospinal fluid through the central canal, the hypoplasia of the posterior fossa, the herniation of hindbrain into the cervical spinal canal, and the compressive damage to cranial nerves. Some of the abnormalities are progressive, and thus treatable. Limitation of progression may improve outcomes. The challenges to our treatment programs involve early diagnosis, delivery by Caesarean section, emergent closure of the neural plaque and prophylaxis of hydrocephalus, anticipatory prevention of the neurological compression syndromes, multidisciplinary teams, and age-appropriate interventions.

Arnold-Chiari Malformation↗
PubMed1991

Production of transgenic birds.

The avian embryo presents a tremendous challenge for those interested in accessing and manipulating the avian germ line. By far the most successful method of gene transfer is by retrovirus vector. The efficacy of retrovirus vectors has been demonstrated by germ line insertion of replication-competent retroviruses as well as the insertion of replication-defective retrovirus vectors carrying bacterial marker genes. Retroviral vectors have also been shown to be useful for the transfer and expression of genes in somatic cells. Further, germ line transgenesis has been reported in both the chicken and the Japanese quail. In addition, several alternative gene transfer methods are under development. These include transfection of avian sperm, development of germ line chimeras using primordial germ cells and blastodermal cells, and the development of embryonic stem cell lines. Potentially, basic research and the poultry industry will derive substantial benefit from this revolutionary technology.

Animals↗
PubMed1991

HLA patterns in children with parainflammatory leukoencephalomyelitis.

We have evaluated the human leukocyte antigen (HLA) phenotype of six children with parainflammatory leukoencephalomyelitis (PIL). Patients with PIL demonstrate an increased prevalence of the HLA-A1, -A28, -B44, -DR6, and -DR7 antigens. These HLA associations are different from those reported in other inflammatory demyelinating diseases, including multiple sclerosis, optic neuritis, Guillain-Barré syndrome, and chronic relapsing inflammatory polyneuropathy. The HLA constitution of the patient appears to be one important host factor in determining the nature of the immune response to an encephalitogenic challenge.

Child↗
PubMed1990

Cystic optic glioma.

A pilocytic astrocytoma of the optic nerve, chiasm, hypothalamus, or third ventricle is a relatively common tumor of childhood. This case report illustrates such a tumor, originating from this location, which is unusual because of the association with two very large cystic extensions into the middle cranial fossa and into the third ventricle. The massive size and extent of this tumor and cysts was demonstrated on a magnetic resonance imaging (MRI) scan, with gadolinium enhancement. This case illustrates a novel macroscopic appearance for a pilocytic glioma of the anterior third ventricle. The purpose of this report is to alert clinicians to the varied morphology this tumor may present as we apply increasingly our improved radiological, operative, and histopathological techniques.

Astrocytoma↗
PubMed1990

The molecular biology of occlusive stroke in childhood.

It is very likely that many of the same factors involved in occlusive disease in the adult are operative in the child. The major difference may be in the factors that damage endothelium in these two age groups and thereby initiate this catastrophe (atherosclerosis versus "other" causes of endothelial changes). Our task in this next decade is the rational exploration of the effects of endothelium-mediated kinins, endothelial secretory products, angiospasm, platelet aggregration, prostaglandins, and lipoproteins on pediatric stroke.

Blood Platelets↗
PubMed1988

The evolution of ischemic cerebral infarction in infancy: a sonographic evaluation.

Cranial sonography provides a noninvasive, portable method for imaging the infant brain. This study describes the time-dependent, sonographic findings of infantile cerebral infarction, as well as computed tomographic (CT) scan and neuropathologic confirmation. Three hundred ninety-five infants under 18 months of age were sonogrammed over a period of 18 months. Three infants were diagnosed by cranial sonography and confirmed by CT scan and/or autopsy to have acute ischemic cerebral infarcts. The cases were followed with serial cranial sonograms for up to 18 months of age. The acute sonographic findings included a hyperechoic zone around the infarcted tissue. The subacute infarct had a checkerboard pattern, while the chronic infarcts were anechoic.

Cerebral Infarction↗
PubMed1987

Gene transfer in swine embryos by injection of cells infected with retrovirus vectors.

Key components for gene transfer to swine embryos using an avian retrovirus are described. A replication-defective reticuloendotheliosis (REV) viral vector can infect and be expressed in pig embryo fibroblasts (PEF). Infection with a replication-competent vector (REV-A) indicates a presumptive block to viral replication in PEF. Swine embryos obtained at the morula stage can be cultured in vitro to the blastocyst stage, injected with retrovirus helper cells or quail embryo fibroblasts producing REV, and transferred to recipient swine with survival to at least 6 wk of gestation.

Animals↗
PubMed1987

Patterns of cerebral arterial injury in children with neurological disabilities.

We reviewed the data from 215 consecutively imaged children who were referred because of neurologic disease. We specifically looked for evidence of cerebral arterial infarction in the form of focal brain damage in an arterial vascular distribution. Twenty-eight showed an arterial infarction pattern. All the major cerebral arteries were involved: middle cerebral artery, 17/28; posterior cerebral artery, 7/28; anterior cerebral artery, 2/28; carotid, 2/28; and vertebro-basilar, 1/28. Six of the 28 subjects had disorders reported to be associated with cerebrovascular damage. Another 13 subjects had other associated disorders, including perinatal distress and presumed anoxia, closed head trauma, hydrocephalus, and dehydration with electrolyte imbalance. Despite a careful search of medical records, we were unable to find any evidence of an adverse event or associated illness for more than one third of the children. These data suggest that cerebral arterial infarction is a more common lesion in the static neurologic disabilities of childhood than previously thought.

Adolescent↗
PubMed1986

Holoprosencephaly and related midline cerebral anomalies: a review.

We propose a simple pathogenetic mechanism that reduces a bewildering variety of central nervous system malformations to a manageable group sharing defects of midline prosencephalic growth. It is neither new nor innovative, but attempts to summarize many pathologic entities within a concept that accounts for known embryologic events and the sequence and timing of those events. We propose midline prosencephalic dysgenesis as a category of malformations including aprosencephaly, holoprosencephaly, septo-optic dysplasia, and agenesis of the corpus callosum.

Abnormalities, Multiple↗
PubMed1986

Midline telencephalic dysgenesis: report of three cases.

A series of three complex cerebral malformations is presented. The series was characterized by incomplete development of the commissural and chiasmatic plate of the developing forebrain. Associated anomalies included hypoplasia of the hippocampus, heterotopias, and nonfusion of the cerebellum. Mild facial anomalies were present, as were somatic anomalies of the heart and kidneys. Emphasis is placed on the order and classification of similar cerebral anomalies.

Abnormalities, Multiple↗
PubMed1985

Gaucher's disease: a case history with extensive lipid storage in the brain.

Patients with acute infantile or type II neuropathic Gaucher's disease demonstrate neurologic deficits that are seemingly greater than the extent of the central nervous system involvement found at autopsy. Examination of the brain of an affected child shows widespread deposition of lipid in a pattern not recognized heretofore. Based on these observations, the authors hypothesize that widespread deposition of the Gaucher glucocerebroside elicits a mild tissue response, which functionally becomes highly significant.

Brain↗
PubMed1985

Central nervous system involvement in congenital visceral fibromatosis.

Congenital visceral myofibromatosis is an uncommon disorder characterized by multiple tumors of myofibroblastic origin in the neonatal period. The natural history of the disorder has been well delineated. The myofibroblast is the cell of origin of the tumor. This is a report of a patient in whom multiple mesenchymal tumors occurred in the CNS as well as in other organs. Light and electron microscopic findings of the CNS lesions are similar to those of the somites and viscera.

Adult↗
PubMed1984

The development of capillaries in the telencephalon of beagle puppies.

The microvessels of the telencephalons of Beagle puppies between newborn and 72 hours of age were investigated ultrastructurally at 24-hour intervals. The morphometry of the microvasculature from the germinal matrix was compared with that of the microvasculature from the borderzone cerebral cortex. The endothelial cell walls of the microvessels from these two sites were similar during the study period, but the lumina of the matrical microvessels were significantly larger than the lumina of the control cortical microvessels. The proportion of matrical microvessels with large lumina undergoes progressive attrition with time. The values (areas) for the lumina of the matrical microvessels, and their distribution, come to resemble those of the cortex. The morphometry of the cortical microvasculature is comparatively static. The data suggest that there is an active modification in the microvasculature of the germinal matrix of the Beagle puppy in the immediate postnatal period.

Animals↗
PubMed1983

Cerebellopontine angle lipoma: a review.

Lipomas located in the cerebellopontine angle (CPA) have rarely been reported. With the advent of computed tomographic scanning and more sophisticated physiological diagnostic techniques, CPA lipomas are being reported more frequently. This paper reviews the world's literature on this lesion and summarizes the symptoms and signs, diagnostic studies, pathology, and surgical results. Recommendations regarding the therapy of this lesion are presented.

Adult↗
PubMed1981

Abnormal brainstem auditory evoked potentials and neuropathology in "locked-in" syndrome.

Brainstem auditory evoked potentials (BAEPs) were studied in a "locked-in" syndrome resulting from multiple occlusions of paramedian pontine arteries. Abnormality of BAEPs (first recorded 10 days after infarction) indicated that brainstem damage extended beyond the basis pontis, where, typically, interruption of corticospinal pathways results in the "locked-in" syndrome. Later, partial BAEP recovery suggested that the technique can be used to distinguish between permanent and transient brainstem involvement. Autopsy examination revealed close correspondence between permanent brainstem damage and persistent BAEP abnormalities. Persistent abnormal prolongation of III-V conduction time and aberration of wave IV were associated with damage near the lateral lemniscus contralateral to the stimulated ear.

Aged↗
PubMed1980

Periventricular leukomalacia. A one-year autopsy study.

We review the frequency and distribution of periventricular leukomalacia (PVL) in consecutive neonatal autopsies in a complete 12-month period. Periventricular leukomalacia occurred in 88% of the high-risk infants. The demographic factors that define risk are a birth weight between 900 and 2,200 g and a survival of six days or more. Virtually all infants with PVL suffered severe clinical insults, and/or had additional necrotic lesions in their viscera. Preferentially, PVL occurs in the cerebral axons in the occipital and sensory-motor radiations. The frequency with which this lesion is found at autopsy may correspond to the frequency with which visual, auditory, and motor dysfunctions occur in surviving premature infants. Electrophysiologic investigations of the high-risk premature infant seem warranted.

Birth Injuries↗