Search Results - (Author, Cooperation:L. O'Connor)

2011-11-15

Nature Publishing Group (NPG)

0028-0836

1476-4687

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

Adult ; Aged ; Aged, 80 and over ; Female ; Gene Expression Regulation, Neoplastic ; *Genetic Predisposition to Disease ; Humans ; Male ; Melanoma/*genetics ; Microphthalmia-Associated Transcription Factor/*genetics ; Middle Aged ; *Mutation ; Sumoylation/genetics ; Young Adult

2018-02-14

The American Society for Microbiology (ASM)

0022-538X

1098-5514

Medicine

0168-1591

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Biology

Electronic Resource

1476-4687

Nature Archives 1869 - 2009

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

[Auszug] THE story of commercial artificial insemination in Great Britain is quite a short one, spanning, in fact, less than twenty years, for it was as recently as November 1942 that the first commercial artificial insemination (A.I.) centre was opened at Cambridge. In 1944, the Milk Marketing Board took ...

Electronic Resource

1432-1106

Female hamster ; Steroid hormone ; Benzodiazepines ; 3H-muscimol binding ; Quantitative autoradiography

Springer Online Journal Archives 1860-2000

Medicine

Summary The levels of gamma amino butyric acid (GABAA) receptors (i.e. 3H-Muscimol binding sites) were determined by quantitative neurotransmitter receptors autoradiography in ovariectomized (OVX), OVX-estradiolo (E), OVX-progesterone (P), OVX-E+P, diazepam (DZ) and DZ + Ro15-1788 treated female hamsters.The various hormonal treatments altered 3H muscimol binding in many brain areas, whereas DZ and DZ + Ro15-1788 had little influence on GABAA receptor levels at the onset of the blocked aggressive behavioral activity. For example, E, P and E+P all significantly increased 3H muscimol binding in medial preoptic area, ventromedial hypothalamic nuclei, and vertical diagonal bandmedial septal nucleus, whereas P treatment increased binding in the caudate-putamen and decreased it in reuniens nucleus of the thalamus. E and E+P treatments increased 3H muscimol binding in the corticomedial amygdala nucleus and hippocampus. Diazepam treatment decreased the GABAA receptor binding in the caudate-putamen and basolateral amygdala, while having no effect in the other brain regions where hormone treatment was effective. In vitro incubation of brain sections with micromolar concentrations of E or P did not change muscimol binding. These results suggest that ovarian steroids, and benzodiazepines to a lesser extent, modulate 3H muscimol binding but do so in different brain regions. The hormone effects on 3H muscimol binding in the critical reproductive centres at a time period that coincides with the onset of its behavioral effect is consistent with a genomic controlled activity.

Electronic Resource

1432-1106

Receptor autoradiography ; Progesterone ; 3H muscimol binding ; Hamster

Springer Online Journal Archives 1860-2000

Medicine

Summary Quantitative receptor autoradiography was applied to evaluate the effects of one and three injections of 1 mg progesterone (P) on 3H muscimol binding levels in the different forebrain areas of the female hamster. The overall effect of P resulted in substantial increases in 3H muscimol binding in brain areas containing gonadal steroid receptors: medial preoptic area and ventromedial hypothalamic nucleus as well as in bed nucleus stria terminalis and subiculum. Similarly, the caudate putamen, a region where gonadal steroid receptors are not abundant, also showed substantial increases of 3H muscimol binding receptor levels. Moreover, female hamsters treated with P for 3 days presented altered 3H muscimol binding levels in the amygdala and thalamic nucleus that were, in some cases, not produced by one dose of P. P treatment also decreased GABAA binding in two areas of the thalamus. These results are consistent with the proposal that P may alter GABAergic inhibitory activity via changes in the levels of GABAA receptors in certain forebrain areas in the female hamster, changes which may be linked to the mediation of anxiolytic effects and to the inhibition of aggressive behavior. These data also suggest that P treatment increases the binding of high affinity GABA receptors in some forebrain sites and may be responsible for maintenance of the anxiolytic effects.

Electronic Resource

1573-4919

Springer Online Journal Archives 1860-2000

Biology

Chemistry and Pharmacology

Medicine

Summary The first reports of the presence of acetyl groups in proteins were concerned with N-terminal acetylation and in 1958 an acetyl peptide was found in a natural protein. The presence of acetyl groups in histories was reported in 1963. N-terminal acetylation can occur in the absence of protein biosynthesis in cell-free systems, although the N-terminus became acetylated while the chain was still on the ribosome. After in vivo administration of 3H-acetate, a displacement of the radioactivity with time towards the higher molecular weight regions is evident. The acetyl groups are bound in the peptidyl moiety of the peptidyl-tRNA. N-terminal acetylation of the H4 histories occurs on the nascent chains in the cytoplasm, whereas internal lysine residues are progressively acetylated after the histone enters the nucleus. The H1 histories containing only the amino terminal acetyl group are the most stable metabolically. Acetylation of chromosomal proteins has been correlated with gene activation and, also, gene inactivation has been correlated with histone deacetylation. Both processes occur rapidly and twice as fast in nuclei from rat hepatoma cells as in nuclei from fetal and adult livers. The arginine-rich histone fraction appears to play a major role in the regulation of RNA synthesis and the arginine-rich histone-specific acetyl transferases may have a major function in the transcription of the genome. Acetyl transferases have been characterized from: pigeon liver acetone fractions, cytosol of uteri from immature rats, rat liver nuclei and cytoplasm, calf liver nuclei and calf thymus cytoplasm, all with different specificities. An acetyl transferase bound to ribosomes active in the acetylation of histories can be solubilized by washing the ribosomes with 0.5 M KCI. Acetylation of ribosomal proteins occurs at a time when the initiation complex is being formed. The acetyl transferase activity of rat liver cytoplasm can be resolved into two components by gel filtration. One component appears to be responsible for acetylation of the epsilon amino group of internal lysine residues in nascent chains. The other component has been investigated to a greater extent and constitutes an RNA-containing proteolipid complex termed complex A which contains enzymes responsible for amino acid activation and the acetylation of polysomal proteins. Electron microscopic studies have revealed a duplex structure with a central hollow in the big unit. Its RNA consists largely of tRNA. The eight lipids, contained therein with the exception of two, were glycolipids. Activities for the enzymatic activation of twelve amino acids: L-Arg, L-Asp, L-Glu, L-GluNH2, Gly, L-Leu, L-Met, L-Phe, L-Pro, L-Ser, L-Thr and L-Tyr may be located on the inside of complex A, while lysine

Electronic Resource

1573-7381

Springer Online Journal Archives 1860-2000

Medicine

Abstract The Long Evans shaker (les) rat is a recently identified CNS myelin mutant with an autosomal recessive mode of inheritance. Although scattered myelin sheaths are present in some areas of the CNS, most notably the ventral spinal cord in the young neonatal rat, this myelin is gradually lost, and 8-12 weeks little myelin is present throughout the CNS. Despite this severe myelin deficiency, some mutants may live beyond one year of age. Rare, thin myelin sheaths that are present early in development lack myelin basic protein (MBP) and on ultrastructural examination are poorly compacted and lack a major dense line. Many oligodendrocytes develop an accumulation of vesicles and membranous bodies, but no abnormal cell death is observed. In the optic nerve, cell kinetic studies show an increase in proliferation at early time points in les, while total glial cell counts are also increased in les from 2 months of age. In situ hybridization studies demonstrate that the numbers of mature oligodendrocytes are similar to controls early in life and increase with time compared to controls. There is both a progressive astrocyte hypertrophy and microgliosis. While les has a mutation in the myelin basic protein (mbp) gene, it is dissimilar in both genotype and phenotype to the previously described mbp mouse mutants, shiverer (shi) and shiverermld. Unlike shi and its allele, where myelin increases with time and oligodendrocytes become ultrastructurally normal, les oligodendrocytes are permanently disabled, continue to demonstrate cytoplasmic abnormalities, and fail to produce myelin beyond the first weeks of life.

Electronic Resource