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Biomedical subjects

J Young

Publications and source records attributed to J Young.

At least 505 records · Page 28Linked to original sources
PubMed1978

Fractures of the odontoid: a laboratory and clinical study of mechanisms.

Previous reports and a study of the mechanism of injury in 25 cases of fracture of the odontoid suggest that the fracture usually results from a high velocity force directed to the head, producing flexion, extension, or rotation of the upper cervical spine. In a laboratory biomechanical study using cadaver preparations, fractures of the odontoid were produced in 20 specimens from the upper cervical spine, which were loaded in failure in forward and lateral modes.

Adolescent↗
PubMed1977

Differences in mouse mammary tumor viruses. Relationship to early and late occurring mammary tumors.

The murine model has been used extensively to study the various factors involved in the etiology of mammary carcinoma. Inbred mouse strains have been classically categorized into (i) high incidence stains with tumors occurring relatively early in the life of the animal, or (ii) low or moderate incidence strains with tumors occurring later on in life. We have radioactively labeled the RNA genome of the mouse mammary tumor virus (MMTV) from each of several mouse strains. We report here, using the technique of molecular hybridization, that the class of MMTVs responsible for the early occurring mammary tumors in high incidence strains can be clearly distinguished from the MMTVs associated with late occurring mammary tumors in low or moderate incidence strains; we also demonstrate that minor differences in MMTV genomes can also exist within these classes. Our findings show that MMTVs are transmitted via the germ line (as a germinal provirus) in some mouse strains, whereas in other strains, a non-germ line transmission is clearly demonstrated. Biochemical techniques can thus be used to track the mode of transmission of oncogenic viruses. The relationship of these findings to an understanding of the etiology of mammary carcinoma is discussed.

Animals↗
PubMed1977

Inhibitory action of porcine follicular fluid upon granulosa cell luteinization in vitro: assay and influence of follicular maturation.

Culture medium 199 supplemented with follicular fluid from 1-2 mm antral porcine follicles inhibited spontaneous luteinization of granulosa cells from preovulatory porcine follicles in vitro. Three characteristics of luteinization were inhibited: morphological transformation, progesterone secretion, and accumulation of cyclic AMP in response to LH. The last was inhibited more effectively by culture media containing 50% follicular fluid than by media containing 20% follicular fluid. The inhibitory actions of the follicular fluid were not altered by charcoal or petroleum ether extraction. Follicular fluid from large follicles (6-12 mm) did not exhibit any of these inhibitory actions. These observations may indicate the presence of a luteinization inhibitor in the fluid of small follicles which (1) is lost by the time the follicle reaches the preovulatory stage, or (2) is overcome by a stimulatory agent which may accumulate as the follicle grows.

Animals↗
PubMed1975

Effect of micelle formation on the absorption of neutral fat and fatty acids by the chicken.

Experiments were conducted to determine the absorption of various dietary fatty acids and glycerides singly and in mixtures. Chickens with or without cannulated bile ducts or ligated pancreatic ducts were used to evaluate the absorption of fatty acids or mixtures of fatty acids and the absorption patterns of several classes of lipids and their effect on the absorption of palmitic acid under in vivo conditions. In spite of wide melting point differences, isomers of various monoglycerides or 18-carbon unsaturated fatty acids exhibited identical absorption and solubility patterns. A homologous series of saturated monoglycerides showed a maximum absorption value for the monoglycerides with fatty acids of 12 and 14 carbons. Absorption decreased with increasing chain lengths of the fatty acid in the monoglyceride. Conversely, the absorption of palmitic acid when fed with the various monoglycerides progressively increased to a maximum in the mixture containing monomyristin and then decreased when fed with monopalmitin or monostearin.

Animal Nutritional Physiological Phenomena↗
PubMed1975

Rectal potential difference in the diagnosis of aldosterone excess.

Rectal potential difference (pd) is directly related to the plasma aldosterone concentration, and rises when aldosterone is stimulated by sodium deprivation. However, when the measurement of rectal pd was tested at a screening test for hyperaldosteronism in 19 hypertensive subjects, four of the eight with primary hyperaldosteronism had a normal pd and four of the eight without aldosterone excess had an abnormally raised potential difference. The technique cannot therefore be recommended as a routine screening test for hyperaldosteronism. No relationship was found between rectal pd and hypertension associated with excess of deoxycorticosterone. Rectal pd rises in response to the mineralocorticoid-like agent carbenoxolone.

Adult↗