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L Hinds

Publications and source records attributed to L Hinds.

12 recordsLinked to original sources
PubMed1995

Comparative study of the antioxidant defence systems in the erythrocytes of Australian marsupials and monotremes.

A comparison of the erythrocyte (RBC) antioxidant metabolites and enzymes in nine marsupial and two monotreme species was carried out. Reduced glutathione (GSH) concentrations were comparable with those reported for other marsupial and eutherian species. An important finding was that the erythrocytes of the southern hairy nosed wombat regenerated GSH faster than the erythrocytes from its close relative, the common wombat. The activities of glutathione-S-transferase, NADH-methaemoglobin reductase, superoxide dismutase, and glutathione peroxidase (GSH-Px), showed similar levels and extents of variation as those observed in other marsupial and eutherian species. Catalase activities in the marsupials were lower than those measured in the two monotreme species and much lower than those reported in eutherian species. A negative correlation, significant at P < 0.05, was observed between GSH-Px and catalase activities in the RBC of the marsupials. Since both these enzymes "detoxify" H2O2, there appears to be a reciprocal relationship between the activities of these enzymes in marsupial RBC.

Analysis of Variance↗
PubMed1995

Comparative erythrocyte metabolism in marsupials and monotremes.

Concentrations of ATP and DPG, activities of 10 enzymes and the glycolytic rates were measured in the erythrocytes of 11 species of marsupials and two species of monotremes. Mean DPG concentrations were greater in the erythrocytes of marsupials than those of eutherian mammals. The opposite is true of ATP. Significant findings from the results of enzyme activities were: high activity of hexokinase (7.39 +/- 0.82 EU/g Hb) in the short-beaked echidna, pyruvate kinase (37.49 +/- 1.0 EU/g) Hb in bridled nailtail wallaby and glucose-6-phosphate dehydrogenase (G6PD; 41.66 +/- 1.24 EU/g Hb) in black-striped wallaby. About 6- to 7-fold difference in the activity of G6PD levels between the two species of wombats was confirmed. Glucose phosphate isomerase activity was also shown to be twice as high in the red cells of the common wombat compared with those of the southern hairy nosed wombat. There were wide variations in the glycolytic rate among the species examined.

Adenosine Triphosphate↗
PubMed1992

Blushing as a function of audience size.

Almost no experimental analysis of blushing has been done since Darwin's observations in 1872. Forty-eight college women watched a videotape intended to elicit blushing, and a videotape not intended to elicit blushing, but elicit physiological responses. A subject was alone, or with one or four persons present. Blushing, which was measured directly with a photoplethysmograph probe on the cheek, was greater during the blushing than nonblushing stimulation. Blushing increased as audience size increased from one to four, but not from zero to one. Audience size and kind of stimulation interacted statistically. Similar results were obtained with ear coloration, cheek temperature, and skin conductance responses, although confidence levels were lower. Cheek coloration and temperature were significantly correlated during nonblushing stimulation, and the zero and one audience conditions, but not during the four audience condition, when blushing was greatest. These results may be placed within the context of emotional effects of audience size generally, including stuttering and speech disturbance, disruption of learning, and self-reported tension.

Adult↗
PubMed1990

Facial coloration and temperature responses in blushing.

Little work on the psychophysiology of blushing has been done since Darwin's 1872 observations. Facial vascular and temperature changes have been largely ignored in psychophysiology. We had 16 female and 16 male undergraduate volunteers watch a videotape intended to produce blushing (the individual's singing recorded the previous day), and a videotape not intended to produce blushing, but elicit physiological responses for comparison (a segment from Hitchcock's movie Psycho). Four people were present as a subject watched these video segments. Cheek and ear coloration, measured photoplethysmographically, cheek temperature, and finger skin conductance responses were significantly greater during stimulation intended to elicit blushing than during comparison stimulation. Gender interacted statistically with kind of stimulation only in cheek temperature. Only video segments of the subject's face that coincided with maximal cheek coloration during stimulation intended to produce blushing were judged reliably as blushing, and then more often in females than in males.

Adolescent↗
PubMed1989

A second form of gonadotropin-releasing hormone (GnRH), with chicken GnRH II-like properties, occurs together with mammalian GnRH in marsupial brains.

GnRH peptides in the hypothalami of marsupials (tammar wallaby, short-nosed bandicoot, and eastern quoll) and a monotreme (echidna) were investigated by reverse phase HPLC and RIA with region-specific antisera. In the wallaby hypothalamic extract, a single form of GnRH was present, which eluted in the same position as synthetic mammalian GnRH on HPLC and was recognized by antibodies directed against the NH2- and COOH-termini of mammalian GnRH as well as by antibodies to the middle region. Two GnRH molecular forms were demonstrated in the bandicoot and quoll hypothalamic extracts. One form eluted in the same position as synthetic mammalian GnRH on HPLC and was quantified equally by two mammalian GnRH antisera. The second form eluted in the same position as synthetic chicken GnRH II and was recognized by specific antibodies to this molecule. Quantification of this immunoreactive peak with two chicken GnRH II antisera was not equal, suggesting that the peptide has similar properties to, but may not be identical to, chicken GnRH II. Immunoreactive GnRH was also detected in the echidna hypothalamic extract. These findings demonstrate that in some mammals more than one form of GnRH is present in the brain of a single species, as has previously been found in species from all nonmammalian vertebrate classes. The finding in marsupial brain of a peptide with properties of chicken GnRH II, which has previously been reported in species of Aves, Reptilia, Amphibia, Osteichthyes, and Chondrichthyes, supports our hypothesis that this widespread structural variant may represent an early early evolved and conserved form of GnRH.

Aging↗
PubMed1981

Hormonal control of the corpus luteum and embryonic diapause in macropodid marsupials.

Embryonic diapause in the macropodid marsupials is associated with an undeveloped corpus luteum (CL) and low levels of progesterone in plasma. The fertilized egg will enter diapause after ovariectomy and can survive for several months but for reactivation to occur the CL must be present and grow, and there must be a rise in plasma progesterone concentrations. Therefore the central question in the endocrine control of this phenomenon is how the activity of the CL is controlled. The pituitary exerts a tonic inhibition on the CL, probably through prolactin, and when this is released, even temporarily, the CL is reactivated. Once reactivated, no pituitary support is needed for either CL growth or steroidogenesis. The membranes of the luteal cells contain abundant prolactin receptors and prolactin probably exerts its inhibitory effect directly on the CL. Prolactin does not appear to affect steroidogenesis directly, since progesterone production in vitro does not differ between quiescent and reactivated CL and is not altered by addition of prolactin or LH. The increase in plasma progesterone after reactivation can be accounted for by the increase in CL mass. We conclude that circulating prolactin inhibits hyperplasia and hypertrophy of luteal cells and that as the prolactin level declines the CL increases in size, causing plasma progesterone levels to rise and blastocyst growth and development to resume.

Animals↗
PubMed1975

Debilitating ossifying fibromas of a white-tailed deer associated with ear tagging.

A 2.3 kg partially ossified fibroma developed apparently within a 4-1/2 month period near a tag inserted in the right ear of a 5-1/2 year old white-tailed doe (Odecoileus virginianus). This growth caused an abnormal head carriage, disturbed feeding and resulted in emaciation. Secondary partially ossified fibromas developed at the left ear tag and in the right external acoustic meatus. The latter fibroma penterated the tympanic membrane. The puncture wounds in the ears associated with the aluminum tags probably provided sites for virus infection and subsequent fibromatosis.

Animals↗