Change in the stability of tendon collagen during ageing in the reptile, Calotes versicolor. A brief note.

Age related changes in the digestibility of tendon collagen of the garden lizard, Calotes versicolor, were traced using type I collagenase from Clostridium histolyticum. Collagen from older lizards showed less susceptibility for collagenase digestion than the younger lizards suggesting increased number of cross-linkages comparable with mammals.     

Alterations in the RNA, protein and free amino acid level of the liver of the garden lizard, calotes versicolor, during aging and partial hepatectomy

The relative RNA content (mg/g wet wt.) in the liver of Calotes versicolor rises till the lizards weight about 15 g and then declines with increasing age. Total RNA (mg/whole liver) reaches the peak at 32–38 g of bodyweight and remains constant thereafter. The protein concentration (mg/g wet wt.) increases more rapidly up to 48 g of bodyweight and then slowly increases during the later half of the lifespan. The total protein (mg/whole liver) also shows the same trend. The specific free amino acid level (mg/g wet wt.) shows a decline till the lizards weigh 32–38 g and thereafter remains at a constant level. Total free amino acid pool (mg/ whole liver) increases more significantly up to 35–38 g bodyweight followed by a slow rise. Partial hepatectomy leads to an increase in RNA, Protein and free amino acid content of the liver at 4 hr after operation followed by a decrease at 24 hr. The changes in protein and free amino acid content were more significant in younger lizards than the older ones.     

Inhibitory effect of cadmium chloride on the cross-linking of collagen in young male garden lizards.

Administration of cadmium chloride (total dose 50 μg) to young male garden lizards results in the increase of solubility of collagen and soluble/insoluble collagen ratio in bone, cartilage and tendon after two weeks of treatment. Total collagen content also tend to decrease. It is suggested that cadmium chloride prevents collagen cross-linking in in vivo condition.     

Blood flow imaging with MR: spin-phase phenomena

Blood flow phenomena occurring when flow is within the magnetic resonance (MR) imaging plane were analyzed. In this situation, the signal intensity of vascular lumina is predominantly determined by spin-phase change phenomena, and section transition effects of moving spins can be neglected. In this paper, we develop the concepts of in-plane flow, with emphasis on the notion that the spatial variations in velocity and acceleration of blood, which mainly occur along vessel walls, are important determinants of intravascular signal loss in MR images. Flow patterns in the large mediastinal arteries were qualitatively and quantitatively analyzed in six healthy subjects and 14 patients with hemodynamic abnormalities using multiple electrocardiograph-gated image acquisition; ungated studies of 30 patients were analyzed for venous flow effects. Intraluminal signal was strongly dependent on the phase of the cardiac cycle and the echo number. Signal loss was found to occur along vessel walls, in vascular bends, and at bifurcations.