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Biomedical subjects

E Gardner

Publications and source records attributed to E Gardner.

At least 19 recordsLinked to original sources
PubMed1992

Complementary physical and genetic techniques map the vinculin (VCL) gene on chromosome 10q.

Vinculin is a cytoskeletal protein component of adherens type cell junctions. The gene had been mapped to 10q11.2-qter. We have used a combination of physical and genetic mapping techniques to refine this localization. Hybridization of the vinculin cDNA probe, HV1, to a human-rodent somatic hybrid panel initially suggested a position of either 10q11.2 or 10q22.1-10q23. Genetic recombination mapping in three-generation families with multiple endocrine neoplasia type 2 (MEN2) indicated a position distal to D10S22 (10q21.1) in 10q22.1-10q23. This was confirmed by hybridization of the vinculin cDNA to flow-sorted translocation derivative chromosomes containing the q21-qter portion of chromosome 10. We conclude that the vinculin locus maps in 10q22.1-q23, distal to D10S22.

Animals↗
PubMed1992

A preliminary analysis of consortium data for markers tightly linked to multiple endocrine neoplasia type 2A.

We have analyzed DNA marker typing data contributed by six independent groups to estimate the pairwise genetic distances between these markers and the locus for multiple endocrine neoplasia type 2A (MEN 2A). We used LIPED to calculate these distances for female, male, and sex-average linkage maps and to determine the corresponding LOD scores. The preliminary analyses of this large data set (89 MEN 2A families and five non-MEN 2A references families, with 1,934 total individuals) are reported here. These refined estimates of the genetic map in this region will aid in the assignment of presymptomatic diagnoses. This study clearly points out the limitation of pairwise linkage analysis in further refining the position of MEN2A in this small region of chromosome 10. Further refinement of the genetic map position of MEN2A will be best accomplished by finding, verifying, and accurately mapping crossovers in specific families.

Chromosome Mapping↗
PubMed1979

Anterior pituitary adenylate cyclase: stimulation by dopamine and other monoamines.

Adenylate cyclase activity of homogenates of anterior pituitary from rat, rabbit and monkey was stimulated by dopamine, other amine neurotransmitters and Gpp(NH)p. The concentration of dopamine for half-maximal stimulation of activity was 2--5 micrometer. Studies with selective agonists and antagonists indicated the presence of dopamine receptors and beta-adrenergic receptors coupled to adenylate cyclase in anterior pituitary. In addition, histamine stimulated activity in rabbit and monkey, but not in rat, anterior pituitary.

Adenylyl Cyclases↗
PubMed1979

The initial development of the human brain.

An account of the early development of the human brain has been prepared from the data available for the Carnegie Collection, as well as from published information from other sources. Although the site of the neural plate can be discerned at stage 7, the first visible indication of the nervous system is the neural groove in certain embryos of stage 8, in which the embryonic disc measures more than 1 mm and the notochordal process at least 0.3 mm. The progressive fusion of the neural folds during stage 10, and the closure of the rostral and caudal neuropores at stages 11 and 12, respectively, are detailed with further precision than hitherto. It is emphasized that the major subdivisions of the human brain do not begin as vesicles, but as enlargements of the open neural folds at stage 9. The relationships of the neuromeres to the otic region, the somites, and the neural crest are clarified and illustrated. The early appearance of the telencephalon medium (before cerebral vesicles have formed) is stressed, and the terminological implications for the subdivisions of the brain are discussed.

Brain↗
PubMed1979

Types of neural cells in the spinal ganglia of human embryos and early fetuses.

Spinal ganglial of human embryos and fetuses ranging in C.-R. length from 15 to 74 mm and in age from 6 1/2 to 11 postovulatory weeks were studied by light and electron microscopy. A sequence of events in differentiation and maturation enabled five types of cells to be distinguished: 1. apolar, undifferentiated neuroblasts are the main cells at 6 1/2 to 7 1/2 weeks; 2. early bipolar neuroblasts (strictly speaking, types 2 to 5 are immature neurons) predominate at the end of the embryonic period proper (8 postovulatory weeks); 3. intermediate bipolar neuroblasts are characteristic of the early fetal period; 4. late bipolar neuroblasts, in which two proceses arise separately from one pole of the cell, appear at about 10 postovulatory weeks; 5. unipolar neuroblasts are found within another week and, by that time, cells of types 1 and 2 are no longer present.

Cell Differentiation↗
PubMed1977

Fibers in monkey posterior articular nerves.

The distribution of axons in the posterior articular nerves in rhesus monkey has been studied in terms of ratio of myelinated to unmyelinated fibers, and size of myelinated fibers. Conduction velocity measurements were also made. The nerves contained 2,000 to 2,200 unmyelinated fibers of 0.2 to 1.2 mum diameter. They contained 399 to 478 myelinated fibers, varying in size from 1.4 to 12.3 mum. Thus 80 to 85% of fibers in these nerves were unmyelinated. The maximum conduction velocity of 70 to 80 meters per second corresponded to an initial small deflection, with most fibers conducting at slower rates. These results are compared to previous reports which severely underestimated the number of unmyelinated fibers because electron microscope counts were not utilized. It is suggested that pain fibers from the knee joint of monkey make up much of this large population of unmyelinated axons. An unknown number of post-ganglionic sympathetic fibers is also included in the unmyelinated fiber group.

Animals↗
PubMed1976

Pathogenesis of methylazoxymethanol-induced lesions in the postnatal mouse cerebellum.

Previous studies have shown that methylazoxymethanol acetate (MAM) and methylazoxymethanol glucoside (cycasin) cause destruction of differentiation cells in the postnatal mouse cerebellum. The major features of the resulting architectural disarray were Purkinje cell misalignment and granule cell deletion along with cerebellar dysfunction. Although it was clear from a number of studies that destruction of differentiation cells in the immediate postnatal period was the primary lesion, several important facets of the pathellular response to the injury was incompletely described. The relationship of the cellular response to the subsequent pathological alterations was not completely evaluated. Also, the presence of unattached Purkinje cell dendritic spine postsynpatic sites suggested that their development had occurred without presynaptic parallel fiber terminal differentiation. The possibility of early synaptogenesis and degeneration was not, however, completely ruled out.

Animals↗
PubMed1976

The nerve supply and conducting system of the human heart at the end of the embryonic period proper.

The nerve supply and conducting system were studied in a stage 23 human embryo of exceptional histological quality. The nerves on the right side arose from cervical sympathetic and from cervical and thoracic vagal filaments. Out of their interconnexions vagoxympathetic nerves emerged, which (1) sent a branch in front of the trachea to the aorticopulmonary ganglion, thereby supplying arterial and venous structures, and (2) formed the right sinal nerve, which supplied the sinu-atrial node, and gave filaments to the interatrial septum which could be traced to the atrioventricular node and pulmonary veins. The nerves on the left side arose similarly from cervical sympathetic and from cervical and thoracic vagal filaments. These formed several descending, ganglionated, vagosympathetic filaments that descended to the right of the arch of the aorta and entered the aorticopulmonary ganglion. Filaments leaving the ganglion supplied the pulmonary trunk, ascending aorta, interatrial septum, pulmonary veins, and, as the left sinal nerve, the fold of the left vena cava. The thoracic vagal filaments descended to the left of the arch of the aorta and supplied chiefly the arterial end of the heart. No thoracic sympathetic cardiac filaments were found. The sinu-atrial node began as a crescentic mass in front of the lower part of the superior vena cava. It gradually extended on each side of the superior vena cava and came to form its posterior wall at a more caudal level. The atrial myocardium that formed the septum spurium, venous valves, and interatrial septum could be traced from the sinu-atrial to the atrioventricular node. Myocardium also encircled the atrial aspects of the atrioventricular orifices, and could be traced caudally to the atrioventricular nde. The atrioventricular node was a conspicuous mass in the anterior and lower part of the interatrial septum, from which a clearly defined bundle left to enter the interventricular septum. Right and left limbs were observed, the former being a rounded bundle that passed immediately in front of the root of the aorta.

Atrioventricular Node↗
PubMed1975

The Dandy-Walker and Arnold-Chiari malformations. Clinical, developmental, and teratological considerations.

Five patients with the Dandy-Walker syndrome had dysgenesis of the cerebellar vermis, cystic dilatation of the fourth ventricle, and a high position of the tentorium cerebelli. When only these features are present, the patient may lead a normal life. Additional defects usually account for the prominent clinical and pathological features of this syndrome. In this series, one patient had aqueductal stenosis, four had agenesis of the corpus callosum, two had hydrocephalus, one had cerebral abiotrophy, and one (a 72-year-old man) had no additional defects and no symptoms from his Dandy-Walker syndrome. An analysis of development and teratological considerations indicates that the Dandy-Walker and Arnold-Chiari malformations are complex disorders that have different causes and mechanisms and begin at different times in the emryonic period. The causes are still unknown.

Adolescent↗