Distinct promoters direct neuronal and nonneuronal expression of rat aromatic L-amino acid decarboxylase.

Aromatic L-amino acid decarboxylase (AADC, EC 4.1.1.

Differentiation status of rat enterocytes after intestinal adaptation to jejunoileal bypass.

The differentiation status of epithelial cells in intestinal adaptation remains unclear. To determine whether enterocytes reach optimum maturity following adaptation after 85% shortening of the rat gut by jejunoileal bypass surgery, activities of two brush border enzymatic markers of differentiation, alkaline phosphatase and sucrase, were examined in subpopulations of epithelial cells isolated sequentially from the villus/crypt axis of normal (sham operated) and hyperplastic mucosa. In jejunal villi, adaptational hyperplasia was associated with an increase in total epithelial alkaline phosphatase, but not total sucrase, activity; alkaline phosphatase activity increased most obviously in cells at the 11-50% position (from the tip) on villi.

Carnivorous plants: phylogeny and structural evolution.

The carnivorous habit in flowering plants represents a grade of structural organization. Different morphological features associated with the attraction, trapping, and digestion of prey characterize a diversity of specialized forms, including the familiar pitcher and flypaper traps. Phylogenetic analysis of nucleotide sequence data from the plastic rbcL gene indicates that both carnivory and stereotyped trap forms have arisen independently in different lineages of angiosperms.

Leukoderma in association with giant congenital nevi: report of two cases.

Two patients are presented in whom giant congenital nevi were associated with hypopigmentation. One patient has had no associated melanoma. The second patient developed hypopigmentation years before a melanoma was excised, and increased hypopigmentation was noted years later without evidence of melanoma recurrence.

Autoregulation of pit-1 gene expression mediated by two cis-active promoter elements.

The pit-1 gene is a member of a large family of genes that encode proteins which are involved in development and which contain a highly homologous region, referred to as the POU domain. Pit-1, a pituitary-specific transcription factor, can activate the transcription of the growth hormone and prolactin promoters. It is expressed in mature thyrotroph, somatotroph and lactotroph cell types of the anterior pituitary which arise sequentially during development; somatotrophs and lactotrophs, which secrete growth hormone and prolactin, respectively, are the last to arise.

Years of potential life lost: another indicator of the impact of cutaneous malignant melanoma on society.

Years of potential life lost (YPLL) is an indicator of premature mortality that complements traditional incidence and mortality rates and that facilitates comparisons among different cancers. We calculated YPLL from cutaneous melanoma and 11 other cancers routinely recorded and tracked by Surveillance, Epidemiology and End Results (SEER). YPLL from cutaneous melanoma ranked eighth for persons younger than 65 years of age and fourth for those 20 to 49 years of age.

The POU-specific domain of Pit-1 is essential for sequence-specific, high affinity DNA binding and DNA-dependent Pit-1-Pit-1 interactions.

Pit-1 is a member of a family of transcription factors sharing two regions of homology: a highly conserved POU-specific (POUS) domain and a more divergent homeodomain (POUHD). Analysis of mutant Pit-1 proteins suggests that, while the POUHD is required and sufficient for low affinity DNA binding, the POUS domain is necessary for high affinity binding and accurate recognition of natural Pit-1 response elements. Pit-1 is monomeric in solution but associates as a dimer on its DNA response element, exhibiting DNA-dependent protein-protein interactions requiring the POUS domain.

Systemic factors are trophic in bypassed rat small intestine in the absence of luminal contents.

Mucosal histology, crypt cell proliferation and brush border enzymes were measured in rats with varying degrees of jejunoileal bypass, in order to compare the effect of systemic and luminal factors on adaptive growth and differentiation (brush border enzymes) in small intestinal epithelium. Eighty five percent jejunoileal bypass caused a functional short gut; in intestine remaining in continuity there were significant increases in segmental weight, villus area and crypt depth, compared with sham operated controls and 25% jejunoileal bypass rats. Despite villus cell hyperplasia in 85% bypass rats, mucosal sucrase and alkaline phosphatase fell in jejunum and remained low in ileum, while leucine amino peptidase rose in ileum.

Relationship between the sympathetic nervous system and vascular smooth muscle: a morphometric study of adult and juvenile spontaneously hypertensive rat/Wistar-Kyoto rat caudal artery.

The relationship between the sympathetic nervous system and vascular smooth muscle has been assessed in adult and juvenile spontaneously hypertensive rats (SHR) and compared with age-matched Wistar-Kyoto rats (WKY) using ultrastructural and light microscopic morphometric analysis of the caudal artery. The absolute volume of smooth muscle in the caudal artery of adult SHR (14-19) months was 169% greater than that in WKY vessels. As well, the axonal volume was 89% greater than that in the WKY.

A two-base change in a POU factor-binding site switches pituitary-specific to lymphoid-specific gene expression.

The structurally related POU homeo domain proteins Pit-1 and Oct-2 activate pituitary- and lymphoid-specific transcription, respectively, by binding to similar AT-rich motifs in their target genes. In this study we identify bases critical for recognition and activation by Pit-1 and examine how small differences in Pit-1 and Oct-2-binding sites can impart differential transcriptional responses in pituitary and B-lymphoid cells. Scanning mutagenesis of Pit-1 response elements in both the rat prolactin and growth hormone genes reveals a critical binding motif recognized in an identical manner by the native Pit-1 protein and cloned Pit-1 gene product.

A family of POU-domain and Pit-1 tissue-specific transcription factors in pituitary and neuroendocrine development.

The anterior pituitary gland provides a model for investigating the molecular basis for the appearance of phenotypically distinct cell types, within an organ, a central question in development. The rat prolactin and growth hormone genes are selectively expressed in distinct cell types (lactotrophs and somatotrophs) of the anterior pituitary gland, which reflect differential mechanisms of gene activation or restriction because of interactions of multiple factors binding to these genes. We find that the pituitary-specific 33,000 dalton transcription factor, Pit-1, normally expressed in somatotrophs, lactotrophs, and thyrotrophs, can bind to and activate both growth hormone and prolactin promoters in vitro at levels even tenfold lower than those normally present in pituitary cells.

A pituitary POU domain protein, Pit-1, activates both growth hormone and prolactin promoters transcriptionally.

The anterior pituitary gland provides a model for investigating the molecular basis for the appearance of phenotypically distinct cell types within an organ, a central question in development. The rat prolactin and growth hormone genes are expressed selectively in distinct cell types (lactotrophs and somatotrophs, respectively) of the anterior pituitary gland, reflecting differential mechanisms of gene activation or restriction, as a result of the interactions of multiple factors binding to these genes. We find that when the pituitary-specific 33-kD transcription factor Pit-1, expressed normally in both lactotrophs and somatotrophs, is expressed in either the heterologous HeLa cell line or in bacteria, it binds to and activates transcription from both growth hormone and prolactin promoters in vitro at levels even 10-fold lower than those normally present in pituitary cells.

Activation of cell-specific expression of rat growth hormone and prolactin genes by a common transcription factor.

In the anterior pituitary gland, there are five phenotypically distinct cell types, including cells that produce either prolactin (lactotrophs) or growth hormone (somatotrophs). Multiple, related cis-active elements that exhibit synergistic interactions appear to be the critical determinants of the transcriptional activation of the rat prolactin and growth hormone genes. A common positive tissue-specific transcription factor, referred to as Pit-1, appears to bind to all the cell-specific elements in each gene and to be required for the activation of both the prolactin and growth hormone genes.

Dietitians' development of an enteral nutrition management package.

Several dietitians at the Royal Victoria Hospital, Montreal, examined current hospital practices in enteral feeding and defined three major areas of concern that are known to influence the management of enterally-fed patients. These concerns deal with physicians' perceptions, nursing management and cost. In order to address these concerns and consequently improve the management of enterally-fed patients, an Enteral Nutrition Management Package consisting of an order form, flow sheet and monitoring record was developed.

A c-erb-A binding site in rat growth hormone gene mediates trans-activation by thyroid hormone.

The substance 3,5,3-triiodothyronine (T3) stimulates growth hormone gene transcription in rat pituitary tumour cells. This stimulation is thought to be mediated by the binding of nuclear T3 receptors to regulatory elements 5' to the transcriptional start site. Understanding of the mechanism by which thyroid hormone activates gene transcription has been limited by failure to purify nuclear T3 receptors because of their low abundance, and by the absence of defined T3 receptor-DNA binding sites affecting T3 regulation.

A single gene codes for aromatic L-amino acid decarboxylase in both neuronal and non-neuronal tissues.

We have sought to determine whether aromatic L-amino acid decarboxylase which functions as a neurotransmitter biosynthetic enzyme in neuronal cells can be distinguished from an enzyme with similar activity found in peripheral tissues where no neurotransmitters are synthesized. Aromatic L-amino acid decarboxylase was purified to electrophoretic homogeneity from bovine adrenal medulla, and highly specific antibodies were produced. In addition, a DNA clone complementary to aromatic L-amino acid decarboxylase mRNA was isolated by immunological screening of a lambda gt11 cDNA expression library.

Two different cis-active elements transfer the transcriptional effects of both EGF and phorbol esters.

Short cis-active sequences of the rat prolactin or Moloney murine leukemia virus genes transfer transcriptional regulation by both epidermal growth factor and phorbol esters to fusion genes. These sequences act in a position- and orientation-independent manner. Competitive binding analyses with nuclear extracts from stimulated and unstimulated cells suggest that different trans-acting factors associate with the regulatory sequence of each gene.

Discrete cis-active genomic sequences dictate the pituitary cell type-specific expression of rat prolactin and growth hormone genes.

The anterior pituitary gland, which is derived from a common primordium originating in Rathke's pouch, contains phenotypically distinct cell types, each of which express discrete trophic hormones: adrenocorticotropic hormone (ACTH), thyroid-stimulating hormone (TSH), prolactin, growth hormone, and follicle stimulating hormone (FSH)/luteinizing hormone (LH). The structurally related prolactin and growth hormone genes, which are evolutionarily derived from a single primordial gene, are expressed in discrete cell types--lactotrophs and somatotrophs, respectively--with their expression virtually limited to the pituitary gland. The pituitary hormones exhibit a temporal pattern of developmental expression with rat growth hormone and prolactin characteristically being the last hormones expressed.

Phenylethanolamine N-methyltransferase-containing neurons in rat retina: immunohistochemistry, immunochemistry, and molecular biology.

We sought to characterize in detail neurons in rat retina that contain phenylethanolamine N-methyltransferase (PNMT), the epinephrine biosynthetic enzyme. Cell bodies and processes of PNMT-containing neurons in retina were identified by immunohistochemistry. The coexistence of other catecholamine biosynthetic enzymes in the same cells was also investigated.

Partial expression of catecholaminergic traits in cholinergic chick ciliary ganglia: studies in vivo and in vitro.

We have previously demonstrated that at embryonic Day (E) 8, some cells of the chick ciliary ganglion (CG) contain the catecholaminergic (CA) enzyme tyrosine hydroxylase (TH), but not phenylethanolamine-N-methyltransferase (PNMT); and that in culture essentially all cells express both enzymes. In the present study, we sought to determine, first, whether the expression of adrenergic traits in the CG in vivo is transient or permanent in the CG. To do so, CGs were removed from E5 to postnatal Day 5, fixed, and processed for the immunocytochemical localization of the CA enzymes: TH, L-amino acid decarboxylase (AADC), and PNMT.

Aromatic L-amino acid decarboxylase in the rat brain: immunocytochemical localization in neurons of the brain stem.

Neurons containing the enzyme aromatic L-amino acid decarboxylase were immunocytochemically localized in the brain stem of the rat. The enzyme occurred as expected in previously well characterized monoaminergic cell groups, and in addition in some nuclei with unknown neurotransmitters. Major aggregates of neurons that were immunoreactive for aromatic L-amino acid decarboxylase but contained neither tyrosine hydroxylase nor serotonin, were found in the pretectal nuclei, the lateral parabrachial nucleus, and the dorsolateral subdivision of the nucleus tractus solitarius.

Olfactory bulb dopamine neurons survive deafferentation-induced loss of tyrosine hydroxylase.

Peripheral deafferentation of the rodent olfactory bulb results in loss of dopamine content, tyrosine hydroxylase activity and immunocytochemical staining for tyrosine hydroxylase in juxtaglomerular dopamine neurons. Reinnervation of the bulb by afferent neurons results in the return of all parameters to control levels suggesting that the dopamine neurons did not degenerate but that the expression of tyrosine hydroxylase enzyme was transneuronally regulated in a static population of juxtaglomerular cells. To evaluate this possibility, we determined the activity and immunocytochemical localization of the second enzyme in the dopamine biosynthetic pathway, DOPA decarboxylase.

Aromatic L-amino acid decarboxylase in the rat brain: coexistence with vasopressin in small neurons of the suprachiasmatic nucleus.

We demonstrated the coexistence of aromatic L-amino acid decarboxylase (AADC) and arginine-vasopressin in neurons of the hypothalamic suprachiasmatic nucleus of Sprague-Dawley rats. Neurons that lacked monoamines but expressed immunoreactivity to the enzyme AADC occupied the rostral and caudal poles of the suprachiasmatic nucleus and mediodorsal and dorsolateral positions along the entire extent of the nucleus. AADC was also localized in similar neurons of the suprachiasmatic nucleus of rats from other strains including the homozygous Brattleboro rat.