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Biomedical subjects

M Turner

Publications and source records attributed to M Turner.

11 recordsLinked to original sources
PubMed1992

Object recognition versus object discrimination: comparison between human infants and infant monkeys.

Human infants (12-32 months old) and adults learned a delayed nonmatching-to-sample (DNMS) task and single- and multiple-pair discrimination tasks using nonverbal procedures previously used with monkeys. Infants learned discriminations rapidly and at a young age (12 months), but they required prolonged training and maturation before learning the DNMS task. Adults learned all tasks rapidly. After learning the DNMS task to criterion, memory performance declined systematically in an inverse relation to age. The dissociation in ability of infants on the DNMS versus discrimination tasks closely resembles the dissociation previously reported with infant monkeys (Bachevalier & Mishkin, 1984). Results from both infant humans and monkeys support a neurocognitive maturational model.

Adolescent↗
PubMed1992

Molecular basis of gonadotrophin action on human granulosa cell function.

We studied in vitro the effects of Follicle Stimulating Hormone (FSH) and Luteinising Hormone (LH) on: 1) mature human granulosa cell proliferation and steroidogenesis; 2) intra-cellular second messenger (cAMP) generation, and the effects of cAMP analogues on cell function; and 3) mRNA expression of the rate limiting enzymes for progesterone and oestradiol synthesis namely: Cholesterol side chain cleavage (P450 SCC), Aromatase (P450 Arom); and 4) LH receptor mRNA expression. FSH maintained or stimulated, whereas LH markedly inhibited, basal granulosa cell proliferation. Steroidogenesis (oestradiol and progesterone production) was dose dependently increased by both gonadotrophins; with LH having the greater effect. However, only LH was able to induce maximal progesterone production. FSH generated about ten fold less cAMP than LH; and low and high doses of cAMP analogue were able to mimic FSH and LH effects respectively. Northern analyses showed that both FSH and LH were able to induce maximal P450 Arom mRNA expression, whereas only LH could stimulate maximal P450 SCC mRNA transcription. Maximal P450 Arom mRNA expression was associated with less cAMP generation than for P450 SCC. LH-R mRNA expression was induced by FSH but the strongest stimulatory effect was with LH. These results indicate that: 1) FSH and LH have markedly different effects on mature granulosa cell function; 2) the differential action of FSH and LH are dose dependently mediated through intracellular cAMP; 3) mRNA expression of P450 SCC and P450 Arom are differentially regulated by gonadotrophins and intracellular cAMP; and 4) LH was the most potent inducer of its own receptor mRNA.(ABSTRACT TRUNCATED AT 250 WORDS)

Cyclic AMP↗
PubMed1975

A study of serum lipoproteins and angiographic evidence of coronary artery disease.

Extensive serum lipid analyses, with specific emphasis on the concentration of serum beta and pre-beta-lipoproteins, were made on 93 patients who had a clinical diagnosis of angina pectoris and were undergoing coronary angiographic studies. Those individuals with abnormal angiographic evidence of obstructive coronary artery disease, including a group with a prior myocardial infarction, have almost uniformly elevated serum beta-lipoprotein levels when related to an arbitrary division based on the mean values for a "normal" adult population at a similar age level. Compared to serum cholesterol and serum triglycerides, the serum lipoprotein concentrations, specifically beta-lipoproteins, appear to be a more useful parameter for predicting the existence of coronary artery disease. Further studies relating clinical risk factors to coronary artery disease might be better approached by using angiography of coronary vessels rather than myocardial infarction or sudden death from coronary artery disease as an endpoint of morbid data.

Adult↗
PubMedDate not supplied

The Fabella Syndrome.

The Fabella Syndrome is recognized by a sharp pain, local tenderness, and intensification of pain in the area of the fabella by full extension of the knee. After diagnostic tests with local anesthesia and ineffective conservative treatment, surgical extirpation may produce lasting relief of symptoms.

Adolescent↗