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Biomedical subjects

J Pearson

Publications and source records attributed to J Pearson.

At least 235 records · Page 13Linked to original sources
PubMed1978

Epidural lipoma simulating lumbar disc protrusion.

Spinal lipomata are usually associated with congenital anomalies. A lipoma, presenting with symptoms, signs and myelographic findings suggestive of a lumbar disc protrusion, is rare. Asymmetry of the origin of some of the scaral nerve roots may be the clue for suspecting epidural lipoma pre-operatively.

Adult↗
PubMed1977

Localization and characterization of phenylethanolamine N-methyl transferase in the brain of various mammalian species.

The distribution of PNMT activity in various regions and nuclei of the rat, monkey and human brain was investigated. The distribution of PNMT activity in the rat brain correlates with the distribution of PNMT immunofluorescence. The PNMT activity in the primate brain is more widely distributed than in the rat brain. High and intermediate enzyme activity values were dound in the same regions of the primate brain as in the rat brain. Intermediate or low levels were also found in various other regions of the primate brain, e.g., basal ganglia, amygdala, septum, habenula. The brain PNMT has the same substrate specificity and similar kinetic properties as the adrenal enzyme. Immunotitration studies revealed cross-reactivity between the homologous adrenal and brain PNMT.

Amygdala↗
PubMed1977

Brain death: I. Angiographic correlation with the radioisotopic bolus technique for evaluation of critical deficit of cerebral blood flow.

An innocuous intravenous portable radioisotopic test using technetium 99m pertechnetate was employed to demonstrate the deficit of cerebral blood flow associated with brain death. The results are compared to those of bilateral carotid and vertebral angiography in 20 patients. Absence of a bolus tracing from the head in the presence of a control tracing of a bolus from the femoral artery in two successive studies one hour apart reliably correlated with the clinical and electroencephalographic findings signifying cerebral death in comatose, apneic patients. Angiography indicated absence of intracranial circulation in 10 patients. Stasis filling or retrograde emptying of arterial vessels (or both) occurred in 7 patients. There was no evidence of venous filling in any of these 17 patients; all of them had either an absent head bolus or an "intermediate tracing." Results indicate that either form of tracing represents a critical decrease of cerebral blood flow. Two other patients had evidence of severely impaired abnormal posterior fossa circulation without angiographic evidence of cerebral circulation; both of these patients had an absent head bolus. An additional patient had an unusually small head bolus, and angiography revealed extravasation of radiopaque material but no evidence of intracranial circulation. We conclude that the bolus technique is a helpful adjunct in diagnosing brain death.

Adolescent↗
PubMed1977

Brain death: II. Neuropathological correlation with the radioisotopic bolus technique for evaluation of critical deficit of cerebral blood flow.

Diffuse necrosis and autolysis were found in the brains from 6 comatose, respirator-supported patients in whom the bolus technique demonstrated no cerebral blood flow during a period exceeding 20 hours prior to cardiac death. When blood flow was insufficient to produce a bolus, there was no evidence of active tissue response to necrosis. In 6 similar patients, when cerebral blood flow was detected by the bolus technique, less extensive necrosis was observed postmortem and there was active tissue response.

Apnea↗
PubMed1977

Effects of depot injections of retinyl palmitate on 7,12-dimethylbenz[a]anthracene-induced preneoplastic changes in rat skin.

The preneoplastic skin changes usually induced by topical application of 7,12-dimethylbenz[a]anthracene (DMBA) to adult rat skin did not appear when animals were treated locally with depot im injections of high doses of retinyl palmitate (RP) prior to exposure to the carcinogen. The epidermal histology after RP-DMBA treatment was similar to that seen in areas exposed to RP alone. Keratinization was inhibited but there was no cellular atypia, evidence of cell injury, or mucous metaplasia. Other features were hyperplasia with acanthosis and thickened stratum granulosum, parakeratosis, intercellular edema, and loss of hair overlying the injection site. Ultrastructurally, the epidermal cells contained conspicuously fewer tonofibrils and increased dense chromatin, when compared to control cells. Skin changes observed following treatment of littermates with DMBA alone included the appearance of giant tumor cells, dyskeratotic cells, nuclear hyperchromatism, increased nucleocytoplasmic ratio, and pleomorphic nuclei and nucleoli. oss of desmosomes, increased tonofibrils, and defects in the basement membrane with epithelial projections into the dermis were also seen. These preneoplastic changes did not regress when application with DMBA was discontinued after 6 weeks; exposure to the carcinogen for longer than 6 weeks resulted in an exacerbation of the abnormal state. RP had profound effects on rat epidermis that interfered with the effects of a potent skin carcinogen. The mechanisms underlying the phenomenon have not been defined. The use of depot injections of the vitamin which avoids both systemic toxicity and the local irritation seen with topical exposure could serve as a model in which the anticarcinogenesis properties of retinoids could be explored.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1976

Anaplastic neuronal tumors of brain.

A multicentric neuronal tumor of brain with unique morphologic features is described. It is compared with four other markedly anaplastic brain tumors containing neoplastic neurons. Demonstration of axon processes, which must be carefully distinguished from other similarly stained structures, is essential for the recognition of such tumors. Recent experience suggests that anaplastic neuronal tumors are more frequent than is generally realized. It is suggested that axon stains should be more widely employed in the investigation of atypical or highly pleomorphic gliomas.

Adult↗
PubMed1976

Neuronal depletion in the globus pallidus of heroin addicts.

Decreased neuronal population densities are described in the globus pallidus of narcotic addicts. Toxicologic studies indicate mixed addiction to be frequent, but exposure to parenteral heroin is the only common factor. This permanent brain damage seems more likely to be caused by recurrent episodes of hypoxia during severe reactions to narcotics than to be related to direct neurotoxic effects of heroin. The lesion may account for some of the long term changes observed in addicts.

Adolescent↗
PubMed1976

Intramyofiber metastases in skeletal muscle.

Autopsy examination in a case of metastatic carcinoma revealed psoas muscle invasion with nests of tumor cells within individual myofibers. Such findings suggest that there is an intracellular route for the spread of malignant tumor in skeletal muscle.

Carcinoma, Small Cell↗
PubMed1976

Investigating possible effects of abestos in city water: surveillance of gastrointestinal cancer incidence in Duluth, Minnesota.

The recent discovery of over one million asbestos-like fibers per liter of Duluth tap water and the suggestive evidence of a link between certain gastrointestinal (GI) cancers and work exposure to asbestos fibers in the air prompted this study. GI cancer incidence data were gathered for Duluth in the same manner as data previously gathered for comparison cities, Minneapolis and St. Paul. Although some differences in GI cancer incidence occurred among the three cities in 1969-1971, there was no consistent pattern of statistically significant differences observed. The number of GI cancers diagnosed in Duluth residents in 1972 was similar to that in each of the previous three years. This study represents the start of ongoing cancer surveillance in Duluth.

Age Factors↗
PubMed1976

Characterization of the oncornavirus particles in the plasma of guinea pigs with L2C leukemia.

The inoculation of L2C guinea pig leukemia cells into strain 2 guinea pigs results in the death of the animals within 12 to 15 days. Death is preceded by the simultaneous appearance in the plasma of (i) elevated leukocyte levels, (ii) extracellular virus particles, and (iii) a particle-associated RNA-directed DNA polymerase. This enzyme activity has a cation preference identical to that of the type B bromodeoxyuridine-induced guinea pig virus, i.e., an Mg2+ optimum at 20 mM and no activity using Mn2+. Competitive molecular hybridization studies also revealed that the plasma of leukemic guinea pigs contained approximately 2 X 10(9) genome equivalents per ml of an RNA that is homologous to the RNA of the bromodeoxyuridine-induced guinea pig virus. Morphological observations indicate that most, but not all, of the extracellular particles observed in leukemia plasma are derived from the intracisternal particles seen in the L2C tumor cells. The possibilities that either two viral populations are present or that the in vivo morphogenesis of the type B bromodexoyuridine-inducible guinea pig virus is markedly different from its in vitro morphogenesis are discussed.

Animals↗
PubMed1976

Congenital total external ophthalmoplegia associated with infantile spinal muscular atrophy. Fine structure of extraocular muscle.

A case of total congenital external ophthalmoplegia associated with infantile spinal muscular atrophy is presented. In the first 29 months of life, ophthalmoplegia has remained complete. Ultrastructure of lateral rectus extraocular muscle indicates a neurogenic process as the basis of the ophthalmoplegia. Light microscopy alone is insufficient to distinguish primary "myopathic" from "neurogenic" disease in external eye muscles.

Child, Preschool↗
PubMed1975

The sural nerve in familial dysautonomia.

In familial dysautonomia there are malfunctions of motor, sensory and autonomic systems. The sural nerve has reduced transverse fascicular area, diminished numbers of myelinated axons (particularly those of small diameter) and very few non-myelinated axons. Catecholamine containing endings are not found in accompanying arteries. These changes are compatible with reduced neuronal populations described in sympathetic and sensory ganglia. The observed pathology accounts for many of the clinical features of the disease and suggests an abnormality in intrauterine development.

Adolescent↗