PubMed Health⌕ Search

Biomedical subjects

M Starling

Publications and source records attributed to M Starling.

6 recordsLinked to original sources
PubMed2006

Cryptic gentes revealed in pallid cuckoos Cuculus pallidus using reflectance spectrophotometry.

Many cuckoo species lay eggs that match those of their hosts, which can significantly reduce rejection of their eggs by the host species. However, egg mimicry is problematic for generalist cuckoos that parasitize several host species with different egg types. Some generalist cuckoos have overcome this problem by evolving several host-specific races (gentes), each with its own, host-specific egg type. It is unknown how generalist cuckoos lacking gentes are able to avoid egg rejection by hosts. Here we use reflectance spectrophotometry (300-700 nm) on museum egg collections to test for host-specific egg types in an Australian generalist cuckoo reported to have a single egg type. We show that the colour of pallid cuckoo (Cuculus pallidus) eggs differed between four host species, and that their eggs closely mimicked the eggs of the host they parasitized. These results reveal that pallid cuckoos have host-specific egg types that have not been detected by human observation, and indicate that gentes could be more common than previously realized.

Adaptation, Physiological↗
PubMed1992

Assessment of myocardial oxidative metabolism in aortic valve disease using positron emission tomography with C-11 acetate.

C-11 acetate has recently been introduced as a tracer of myocardial oxidative metabolism with the use of positron emission tomography. To evaluate this approach in the pressure- or volume-loaded heart, C-11 acetate clearance rate constants were determined in 22 patients with chronic aortic valve disease and in nine normal subjects. Global myocardial C-11 clearance was significantly higher in patients with predominant aortic stenosis (n = 11) or aortic regurgitation (n = 11) than in normal subjects (0.069 +/- 0.017 min-1 and 0.072 +/- 0.010 min-1 compared with 0.050 +/- 0.004 min-1, p less than 0.05) and correlated significantly with the rate-pressure product corrected for mean aortic valve gradient (r = 0.73, p = 0.0001) for all studies. However, analysis of patient subgroups demonstrated that this correlation held only for aortic stenosis (r = 0.79, p less than 0.005 for gradient-corrected rate-pressure product). Additionally, C-11 clearance was strongly correlated with the product of heart rate and mean wall stress in patients with aortic stenosis (r = 0.89, p less than 0.005) but not in patients with aortic regurgitation. Normalization of C-11 acetate clearance rate constants for gradient-corrected rate-pressure product were significantly lower in patients with loaded ventricles, particularly in the presence of a low ejection fraction, compared to normal subjects. Possible mechanisms include myocardial adaptation through hypertrophy or depressed contractility, which would both tend to reduce oxygen consumption under any given load. Serial comparison of C-11 acetate kinetics and noninvasive indexes of oxygen demand may provide assessment of disease progression in pathologic ventricular loading.

Acetates↗
PubMed1978

Cell kinetics in the erythroid compartment of guinea pig bone marrow: a model based on 3H-TdR studies.

A model of steady-state erythropoiesis in the guinea pig is described. The model incorporates an unidentified progenitor compartment, as well as compartments representing proerythroblasts, basophilic, polychromatic and orthochromatic cells. A computer representation of the model permits a simulation of the labeling curves obtained in pulse and intermittent labeling regimes. It was found that a reasonable fit to the data can be achieved when the parameters for the various compartments are essentially identical. The results of a preliminary sensitivity analysis, carried out by perturbing the duration of S phase from the best fit value, are reported. The fit achieved to the data supports the hypothesis underlying the model that each compartment corresponds to one generation and that the flux within and between compartments is sequential.

Animals↗
PubMedDate not supplied

Twenty-four hour pressure area management: study report.

The aim of the pilot study presented in this article was to evaluate the effectiveness of an alternating-pressure mattress overlay (AlphaXcell) used in combination with a pressure-reducing cushion (Multitec) in providing 24-hour pressure area care in a wide range of patients within a district general hospital.

Aged↗