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Biomedical subjects

L Austin

Publications and source records attributed to L Austin.

At least 73 records · Page 4Linked to original sources
PubMed1983

Increased in vitro labeling of stable RNA within the rat nodose ganglion following abdominal vagotomy.

An in vitro procedure for labeling of RNA in the excised rat nodose ganglion was used to evaluate the changes in incorporation of [3H]uridine into ganglionic RNA following transection of the abdominal vagus nerves. Significant increases in the incorporation into 28S, 18S and 4S RNA were observed at 1 day after injury, which were maximal at 4 days before returning to unoperated control level by 7 days. A second transient increase in the labelling of these RNA species occurred between 9 and 11 days after injury. Comparison of the time course of these increases with those seen previously following cervical vagus nerve crush injury indicate that the time of onset of the increase in incorporation in independent of the site of injury, but that the maximal response is delayed by 1 day with the more distal lesion. These data are consistent with the existence of separate signals for initiating and modulating the cell body response to axon injury, which are transported retrogradely from the site of injury at rates exceeding the slow component of axoplasmic transport.

Animals↗
PubMed1983

Thermodynamic behaviour of membrane enzymes in Duchenne muscular dystrophy.

Erythrocyte ghost preparations have been prepared from blood of Duchenne patients (DMD), female carriers of the disease and controls. Arrhenius plots of Na+, K+-ATPase activity of these membrane preparations show a biphasic response for controls. For 75% of DMD and carriers the response is monophasic. This is not an inherent property of the membrane since it can vary over time in the one individual and it can be induced in normal membranes by preincubation with DMD plasma. Arrhenius plots of AChE activity showed no such difference between the three sources of blood.

Acetylcholinesterase↗
PubMed1983

Brief psychotherapy in late adolescence: a psychodynamic and developmental approach.

Four cases were discussed in which college students presented themselves in crisis for psychiatric treatment; each was dealing with a normal developmental crisis of late adolescence centering around separation-individuation issues. A type of brief psychotherapy was described which maintained the focus on the primary dynamic conflict and promoted ego development by interpreting the unconscious intrapsychic conflict. The incestuous, aggressive, and regressive themes were explored, and defenses were actively interpreted whenever they interfered with the awareness of autonomous strivings consistent with the ego ideal. Although other authors have emphasized the necessity of establishing a contract early which specifies the number of visits, we have emphasized the importance of maintaining strict therapeutic neutrality, especially regarding the duration of treatment with late adolescents. We view this as an important cornerstone of technique in assisting the healthy late adolescent in his quest for increasing autonomy, ego-ideal integration and ego mastery.

Adjustment Disorders↗
PubMed1983

Plasma lipoproteins in Duchenne muscular dystrophy.

Plasma lipoproteins of Duchenne muscular dystrophy patients and carriers of the disease, together with age- and sex-matched controls, were examined by density gradient ultracentrifugation and agarose gel electrophoresis. Analysis of density gradient profiles revealed a significant reduction in absorbance (435 nm) by low density and high density lipoproteins from Duchenne patients when compared with controls. Although no abnormalities were observed on electrophoresis of whole plasma samples, the isolated low density lipoprotein fractions from Duchenne patients and carriers displayed increased electrophoretic mobility compared with controls. The results obtained implicate the plasma lipoproteins, in particular the low density lipoproteins, as the primary site of the lesion in this disease.

Adolescent↗
PubMed1982

Protein turnover in brain during the development of alcohol dependence.

The chronic effect of ethanol on central nervous system protein turnover was investigated in selected regions of brain following intoxication and withdrawal in a strain of ethanol preferring mice. Mice were serially injected with [14C]glucose in order to achieve a constant specific radioactivity of brain glutamate. Protein turnover was calculated from the specific activities of extracted protein and free glutamate. Results from these studies show that ethanol causes a significant increase in protein turnover in all sections of brain. The brain protein turnover in animals following alcohol withdrawal also shows an increase which deviates significantly from controls in 2 of the 3 regions examined.

Alcohol Drinking↗
PubMed1981

Characterization of the association of two small molecular weight RNAs with eukaryotic polysomes.

Previous studies of the adult rat cerebral cortex have shown that two of the small molecular weight RNAs, K and L, are primarily cytoplasmic in location and are present in significant quantities in the microsomal fraction. We have examined their appearance in microsomal preparations. The results demonstrate that both K and L are, in fact, associated with polyribosomes. In particular, it is shown that (i) K and L are present in both membrane-bound and free polysomes; (ii) removal of microsomal membranes with Triton X-100 does not alter their association with microsomal polysomes; (iii) all of the K and almost one-half of the L associated with rat liver polysomes are resistant to high salt washing; and (iv) K and L are present in rabbit reticulocyte-free polysome preparations. The protein synthesis inhibitors cycloheximide and aurintricarboxylic acid significantly alter the association of K and L with rabbit reticulocyte-free polysomes. It is concluded that K and L are transiently associated with polysomes during the process of protein synthesis.

Aging↗
PubMed1981

Differential and coordinate regulation of the eukaryotic small molecular weight RNAs.

We have detected within the adult rat cerebral cortex 9 identifiable small molecular weight RNAs, K, K', L, Q, A, C, D, G', and H. These molecules are electrophoretically similar to the small RNAs found in other mammalian cells. Metabolic turnover and subcellular fractionation studies demonstrate that each of these small RNAs behave in a manner distinguishable from the other 8. In addition, 2 of the small RNAs, K and A, are under considerable developmental regulation. The results obtained suggest that no 2 of these molecules are present exclusively within the same subcellular structure. The cellular concentrations of the small RNAs were analyzed in 7 different adult rat tissues which varied 10-fold in their cellular RNA concentrations. The cellular levels of the cytoplasmic RNAs, 28 S, 18 S, and 5 S rRNA, 4 S tRNA, K, and L, were found to be a function of the total cellular RNA concentration. In contrast, the cellular levels of the nuclear RNAs, A, C, D, and H, varied slightly between tissues and were independent of the total cellular RNA concentration. However, these variations in the levels of the nuclear RNAs were significant in that they revealed these molecules are coordinately regulated.

Animals↗
PubMed1979

Depression simulating organic brain disease.

The authors report four cases of depression manifesting as organic brain syndrome in adult nongeriatric patients. The correct diagnoses in three cases were made by a psychiatrist's or resident's empathic response to the patient, and in the fourth by the patient's history of depression. The authors state that only by maintaining a high degree of suspicion and trusting one's empathic response to the patient will unusual presentation of depression be recognized.

Adult↗
PubMed1978

Phospholipid composition and metabolism in mouse muscular dystrophy.

1. The composition and metabolism of phospholipids were studied in various tissues from both normal and dystrophic mice of the 129 ReJ strain. Phospholipids extracted from forebrain, spinal cord, sciatic nerve and plasma were fractionated by t.l.c. and measured. 2. Very significant alterations were found in the choline phospholipids from these tissues, except forebrain. Plasma phosphatidylcholine in the dystrophic mouse was increased by 38%. There was a 2-fold increase in lysophosphatidylcholine in the spinal cord of dystrophic mice. The sciatic nerve showed a marked decrease in sphingomyelin content, which is approximately half of that in the controls. 3. Five enzymes involved in phosphatidylcholine metabolism [namely cholinephosphotransferase (EC 2.7.8.2); phospholipases A (EC 3.1.1.4, EC 3.1.1.32); lysophospholipase (EC 3.1.1.5); lysophosphatidylcholine acyltransferase (EC 2.3.1.23); phospholipase C (EC 3.1.4.3)] were studied in tissue preparations from forebrain, spinal cord, sciatic nerves, gastrocnemius muscles and liver. 4. Activities of phospholipases A and C were significantly increased, about 5-fold and 60% respectively, in gastrocnemius muscle of dystrophic mice compared with controls. Phospholipases A also showed 50% higher activity in the sciatic nerves of dystrophic than of normal mice. Lysophosphatidylcholine acyltransferase activities were significantly increased in the sciatic nerves and spinal cord, by 50-100% over that of the controls. The forebrain and spinal cord from dystrophic mice, however, had only 60% of lysophospholipase activities of that of the normal control. Cholinephosphotransferase activity was unchanged in these tissues from both normal and dystrophic mice. 5. It is suggested that are number of features of mouse muscular dystrophy related to altered membrane structure and function can be rationalized in terms of changes in lipid composition and metabolism.

1-Acylglycerophosphocholine O-Acyltransferase↗
PubMed1978

Axonal transport of 4S RNA in the chick optic system.

The axonal transport of tRNA has been investigated in the chick optic system. Chicks were injected with [3H]uridine intraocularly or intracranially and the RNA of the retina, nerve complex, and tecta separated by polyacrylamide gel electrophoresis and then counted. The ratio of tRNA to rRNA specific activities increased with time in both the nerve complex and contralateral tectum. The ratio increased more rapidly in the nerve complex than the tectum. However, no increase was observed in the case of intracranially injected animals. This is consistent with the axonal flow of tRNA. When [methyl-3H]methionine was used as precursor, the preferential labeling of 4S RNA to rRNA which resulted more clearly showed a transport of 4S RNA from the retinal cells to the tectum. In conclusion, it was found that about 40% of the radioactive RNA observed within the optic tectum 4 days after an intraocular injection of [3H]uridine was accounted for by 4S RNA which has flowed from the retina. However, the migration of a methylated RNA molecule of size 4S, but unrelated to rRNA, cannot be entirely eliminated.

Animals↗