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Biomedical subjects

P H Patterson

Publications and source records attributed to P H Patterson.

At least 127 records · Page 7Linked to original sources
PubMed1985

Small intensely fluorescent cells in culture: role of glucocorticoids and growth factors in their development and interconversions with other neural crest derivatives.

The neural crest gives rise to a number of adrenergic derivatives, including sympathetic neurons and adrenal chromaffin cells, which contain catecholamines (CAs) but differ in other morphological and functional characteristics. Small intensely fluorescent (SIF) cells, which exist primarily as a minority cell population in autonomic ganglia, are a third cell type in the sympathoadrenal branch of the neural crest lineage. In some respects these cells appear intermediate in phenotype between sympathetic neurons and adrenal chromaffin cells. We established pure dissociated cell cultures of SIF cells from rat superior cervical ganglia (SCG) and used these to study the role of environmental factors in SIF cell development and the relationship of these cells to the other cell types of the sympathoadrenal lineage. When cells from neonatal rat SCG were grown for 3 weeks in the presence of glucocorticoid and in the absence of nerve growth factor (NGF), pure cultures of SIF cells developed. The properties of the cells included (i) small cell size and the occasional presence of short neurites, (ii) intense CA histofluorescence and immunoreactivity for CA synthetic enzymes, (iii) synthesis and storage of CA from radioactive precursors, and (iv) characteristic ultrastructure. The concentration of the glucocorticoid and the presence or absence of non-neuronal cell factors influenced which types of SIF cells developed. In micromolar glucocorticoid most of the cells resembled adrenal chromaffin or type II SIF cells: they displayed immunohistochemically detectable phenylethanolamine-N-methyltransferase (PNMT), synthesized and stored epinephrine, and contained large granular vesicles (100 to 300 nm). When SCG cells were grown in 10(-8) M hormone, many fewer SIF cells developed and a higher percentage of these lacked PNMT immunoreactivity, had neurites, and contained vesicles of smaller mean diameter (70 to 130 nm), similar to those of type I SIF cells in vivo. In the presence of conditioned medium (medium conditioned by non-neuronal cells) as well as glucocorticoid, virtually all of the cells morphologically resembled type I SIF cells. In the absence of glucocorticoid, no SIF cells were ever observed after 3 weeks in culture. By following the development of CA histofluorescence and SIF cell ultrastructure in the cultures over time, we demonstrated that SIF cells were not present in large numbers in these cultures immediately after plating, but were induced from an apparently undifferentiated precursor by the hormonal environment, whereas most of the principal neurons died.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1984

Leg deformities: inability to increase severity by increasing body weight of chicks and poults.

Five 4-week experiments were conducted to determine the effects of body weight on the severity of leg deformities in broiler chicks and turkey poults reared on raised wire floors. In order to make the influence of body weight independent of genetic, environmental, and nutritional effects, increasing body weight was achieved by harnessing steel weights on the backs of poults and chicks. In the first experiment, 3-day-old male and female chicks were harnessed with 0-, 1-, 2-, or 3-g weights (nine chicks per weight load). Weights were changed every 3 to 4 days until 4 weeks of age such that the artificial weight averaged 0, 3, 4.5, or 8.5% of their body weight. In Experiments 2 and 3, three replicates of 10 female chicks were assigned to isocaloric diets containing 18, 21, or 24% crude protein. Five chicks in each treatment and replicate were harnessed at 3 days of age with weights averaging approximately 13% of their body weight. Weights were changed weekly. Experiments 4 and 5 were designed similar to Experiments 2 and 3 except that male and female turkey poults were fed 22, 25, or 28% dietary crude protein and were harnessed with weights equal to about 8 to 10% of their body weight. Body weights of the birds were recorded weekly.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1983

Tyrosine hydroxylase activity decreases with induction of cholinergic properties in cultured sympathetic neurons.

Establishment of transmitter phenotype is an essential step in neuronal development. Studies on rat sympathetic neurons both in vivo and in vitro have provided evidence that mature cholinergic sympathetic neurons arise from previously noradrenergic neurons. Cultured rat superior cervical ganglion neurons can be influenced by their environment to remain noradrenergic, to acquire dual transmitter function, or to become predominantly cholinergic. Several other neuronal traits, such as a variety of surface molecules and released proteins, change simultaneously with levels of catecholamine and acetylcholine production, suggesting that various components of transmitter phenotype are regulated in concert. In this report, tyrosine hydroxylase levels are compared in neurons cultured under noradrenergic, dual function, or cholinergic conditions. Both enzyme activity in cell extracts and immunocytochemical staining were measured. These methods showed significantly less tyrosine hydroxylase enzyme activity and immunoreactive material in cholinergic cultures compared to noradrenergic and dual function cultures. These data support the interpretation that a switch in transmitter status from noradrenergic to cholinergic has occurred. This interpretation contrasts with that of Iacovitti et al. (Iacovitti, L., T. H. Joh, D. H. Park, and R. P. Bunge (1981) J. Neurosci. 1: 685-690), who conducted their experiments under critically different culture conditions.

Adrenergic Fibers↗
PubMed1981

Adolescents with abnormal cervical cytology.

Cytology screening is an important diagnostic tool to detect precancerous and cancerous lesions of the uterine cervix. Cervical intraepithelial neoplasia (CIN) represents a continuum of neoplastic alterations, from mild dysplasia to carcinoma in situ. Our high incidence of 32/1,000 adolescent girls with abnormal cervical cytology, suggestive of CIN, supports studies showing that major cervical pathology does exist in this age group. The importance of this problem, previous experiences, reliability of screening, management, and associated risk factors are reviewed. We advocate that the sexually active older adolescent, 18 to 21, have PAP smears at least yearly. It is also our feelings that sexually active adolescent under 18 should have annual PAP smears, even though our studies revealed a paucity of significantly abnormal findings in this age group.

Adolescent↗
PubMed1981

On the role of cyclic nucleotides in the transmitter choice made by cultured sympathetic neurons.

Previous investigations have established that electrical activity or chronic depolarization influences the development of neonatal rat sympathetic neurons in dissociated cell culture. Depolarization reduces their ability to respond to a cholinergic inducing factor produced by non-neuronal cells, allowing normal adrenergic differentiation to proceed (Walicke, P., R. Campenot, and P. Patterson (1977) Proc. Natl. Acad. Sci. U. S. A. 74: 5767-5771). The present study examines whether the developmental effects of depolarization are mediated through cyclic nucleotides. Addition of dibutyryl cAMP, dibutyryl cGMP, adenosine, prostaglandin E1, and cholera toxin all raise neuronal cyclic nucleotide levels and qualitatively mimic the developmental effects of depolarization. However, the quantitative decrease in acetylcholine production caused by these cyclic nucleotide agents is much smaller than that caused by depolarization. Short (48-hr) exposures to the cyclic nucleotide derivatives do not alter transmitter synthesis, indicating that long term developmental changes are involved. Chronic depolarization with elevated K+ increases neuronal cAMP 2-fold but has little effect on cGMP. The increase in cAMP is maintained during several weeks of depolarization and is present as early as the 3rd day in vitro, preceding the significant alterations in adrenergic and cholinergic differentiation. Exposure to 2 mM theophylline also increases neuronal cAMP, but in contrast to the other agents, it enhances cholinergic differentiation. In combination with elevated K+, theophylline further increases neuronal cAMP but still favors cholinergic differentiation. Thus, although cAMP satisfies some criteria for being the second messenger in the developmental effects of depolarization, several findings are consistent with the nucleotide playing a central role: (i) Depolarization has much larger effects on transmitter choice than the cyclic nucleotide agents and (ii) theophylline can uncouple cyclic nucleotide levels from the developmental events.

Acetylcholine↗
PubMed1981

Neuronal cell surfaces: distinctive glycoproteins of cultured adrenergic and cholinergic sympathetic neurons.

Cell surface components which are candidates for a role in nerve-target interactions specific for neurons of particular transmitter types in the sympathetic nervous system have been identified. Neurons of superior cervical ganglia of neonatal rats were dissociated and cultured in the virtual absence of non-neuronal cells under conditions previously found to control their choice of neurotransmitter. When raised in medium conditioned by heart cells, the neurons become cholinergic; when raised in medium which depolarizes them, the neurons remain in their original adrenergic state. The cell surface proteins of the neurons were labeled by either metabolic or surface-specific methods, separated by two-dimensional polyacrylamide gel electrophoresis, and visualized by autoradiography. A total of approximately 35 glycoproteins can be resolved, of which at least 14 are exposed on the cell surface. We evaluated glycoproteins of neurons raised under conditions which differ in their potency for inducing cholinergic properties: medium conditioned by skeletal muscle, liver, or heart cells or medium containing 1 mM butyric acid. The expression of three neuronal glycoproteins was correlated with the ability of a given culture condition to induce the synthesis and accumulation of acetylcholine or catecholamines. Two of these proteins are exposed on the cell surface, and the third appears to be identical with a protein previously shown to be secreted into the culture medium.

Acetylcholine↗
PubMed1980

Preliminary studies on the use of monoclonal antibodies as probes for sympathetic development.

The precise structural organization and proper functioning of the adult nervous system depend on the ability of neurones to make highly ordered synaptic connexions. To define molecules involved in the development of these connexions and to study their functional roles, we use primary cultures of dissociated rat sympathetic neurones grown in the virtual absence of non-neuronal cells. These neurones can develop adrenergic or cholinergic properties, depending on the environment in which they are grown. This ability to manipulate neuronal phenotype is being used in an attempt to identify cell surface macromolecules that are important in the development or function of adrenergic and cholinergic properties. We have produced monoclonal antibodies against the surface membranes of these neurones and are in the process of characterizing them. Results are presented on the binding specificity of one of these antibodies and on the effect of two other antibodies on neurotransmitter synthesis, uptake, and release.

Acetylcholine↗