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Biomedical subjects

J H Austin

Publications and source records attributed to J H Austin.

At least 91 records · Page 5Linked to original sources
PubMed1979

Studies in aging of the brain: IV. Familial Alzheimer disease: Relation to transmissible dementia, aneuploidy, and microtubular defects.

Alzheimer disease was transmitted in a pattern consistent with an autosomal dominant trait in three families. This brings to 50 the number of such families reported. In one of our families, one patient had histologically confirmed Alzheimer disease, whereas her sister had proved spongiform encephalopathy. Other data suggest a link between familial Alzheimer disease and transmissible dementia. Alzheimer disease is associated with abnormal neurofibrillary structures, Down syndrome, and abnormal numbers of chromosomes in lymphocytes (aneuploidy). These observations are consistent with a disorder in the physiology of tubular-filamentous structures involving different cell types.

Adult↗
PubMed1978

Precautions in familial transmissible dementia: including familial Alzheimer's disease.

Recent studies suggest that some cases of familial Alzheimer's disease may be associated with a transmissible dementia. Animal experiments show that presymptomatic carriers of "slow virus" agents can transmit disease. Because of these findings, we have extended the precautions previously delineated to include those at risk of acquiring transmissible dementia, specifically, to the descendants of those affected with familial Alzheimer's disease or familial Creutzfeldt-Jakob's disease. Blood donation from such persons may pose a danger, because transmissible spongioform encephalopathy has been passed from animal to animal by blood serum and by the WBC layer of frozen whole blood.

Alzheimer Disease↗
PubMed1978

The effects of minor degrees of obliquity on the lateral chest radiograph.

Minor degrees of obliquity affect the appearance of the lateral chest radiograph. For 100 normal subjects we compared findings on three left lateral projections: the "straight lateral", rotation of the subject's right side 10 degrees anterior ("right anterior"), and rotation of the patient's right side 10 degrees posterior ("right posterior"). A number of structures appeared generally best seen in the "right anterior" lateral projection, less well seen in the "straight posterior" lateral projection and least well seen in "right posterior" lateral projection. These structures were the epicardial fat stripe and pericardial line, the anterior margin of the ascending aorta, the hilar vessels, the origins of the upper lobe bronchi, and the posterior wall of the bronchus intermedius. The heart appeared largest in the "right anterior" lateral view, while in the "right posterior" lateral view it appeared smallest (whether assessed subjectively or by measurement of posterior left ventricular overlap of the inferior vena cava). Similarly, the hilar vascular shadows and major bronchi were most prominent when rotated apart in the "right anterior" projection and least prominent when more nearly superimposed in the "right posterior" projection. Slight rotation showed no significant effect on the anteroposterior diameter of the trachea, the width of the left pulmonary artery, or the diameters of the upper lobe bronchi. The azygos vein and a well visualized posterior tracheal band were seen in a few patients. They tended to be best and most frequently seen in the "right posterior" lateral view. Either obliquity tended to improve delimeation of the anterior pleural margins and the costophrenic angles. This was also true for the interlobar fissures, but confusing superimposition shadows were less likely in the "right anterior" than the "right posterior" lateral radiograph.

Aortography↗
PubMed1977

The right paratracheal stripe.

The right paratracheal stripe (RPS) is seen on postero-anterior chest radiographs as a thin, water-density stripe between the air column of the trachea and the adjacent right lung. The range of width of the RPS in 1,259 normal subjects was 1 to 4 mm. An RPS width of 5 mm or more is reliable evidence of disease. The differential diagnosis of this finding is lengthy, and best divided into those diseases affecting the (a) trachea; (b) mediastinum; and (c) pleura.

Adolescent↗
PubMed1976

Studies of connections between locus coeruleus and cerebral cortex.

Small tracking electrodes were inserted into the cat locus coeruleus (LC), and the effects of LC stimulation were determined on the transcallosal potential (TCP) evoked in cerebral cortex on the same side. LC stimulation at 8 volts inhibited TCP amplitude an average of 11%. Rostral LC placements appeared most effective. LC stimulation, without drugs, did not affect the peak latency of the TCP. dl-Propranolol and FLA-63 blocked LC inhibition of the TCP and also increased TCP amplitude per se. Propranolol first increased the latency of the TCP during LC stimulation, then decreased decreased it, while also prolonging the latency of the TCP per se. Phenoxybenzamine increased rather than blocked the LC inhibitory effect and also increased TCP amplitude. dl-Erythro-DOPS slightly increased the LC inhibitory effect, and substantially increased TCP amplitude. dl-Threo-DOPS produced somnolence in unanesthetized animals, led to increased norepinephrine levels in cortex and brain stem, and caused cortical potentials to fluctuate widely. A midbrain lesion of the dorsal ascending NE bundle blocked the LC inhibitory effect. LC stimulation alone, or in combination with evoked cortical stimulation, did not affect the interstimulus electrocorticogram or the heart rate. In the transcallosal system of the cortical regions studied, the LC appears to play mainly an inhibitory role.

Animals↗
PubMed1976

A system for measuring the noradrenaline receptor contribution to the flexor reflex.

A system is described for recording psoas muscle contractions in response to stimuli delivered to the sole of the foot of the acute spinalized unanaesthetized rat. Clonidine, an alpha adrenergic receptor agonist, caused a major increase in this flexor reflex amplitude. The increase was blocked by phenoxybenzamine at a dosage level of 20 mg/kg which did not, of itself, reduce flexor reflex amplitude. Older, larger rats responded significantly more forcefully to clonidine than did younger, smaller rats. However, these differences between rats of different size tended to disappear when the data were expressed in terms of 0/0 of original baseline amplitude. L-dopa, 75 mg/kg, increased the flexor reflex amplitude more so than did L(+)erythro dihydroxyphenylserine (DOPS) at twice the disage in rats pretreated with reserpine and nialamide. Other DOPS isomers were less effective, and L(-)threo DOPS was toxic. These results support the view that spinal noradrenaline receptors exist that increase the psoas flexor reflex. The advantages of the present system are twofold: first, the results may be quantitated; second, small amounts of potential central noradrenaline receptor agonists and antagonists may be tested for their effect on the flexor reflex using relatively few unanaesthetized rats.

Animals↗
PubMed1975

Bilateral adrenal enlargement in Addison's disease caused by tuberculosis. Nephrotomographic demonstration.

Nephrotomography showed markedly enlarged adrenal glands in a 67-year-old man with acute Addison's disease due to tuberculosis. Other causes of acute adrenal insufficiency associated with enlarged adrenals are histoplasmosis and, rarely, bilateral metastatic carcinoma, amyloidosis, or hemorrhage. Radiologic demonstration of large adrenal glands in a patient with acute Addision's disease should strongly suggest an infectious etiology.

Addison Disease↗