No abstract

This study was carried out to record the detailed morphometric structure of the trachea in dogs using 15 female and four male healthy adult mongrel dogs. The diameter and thickness of each tracheal ring were measured, the number of tracheal rings varying from 36 to 45. All data were subjected to statistical analysis which was carried out on individual sections of the trachea, i.e. the cranial cervical, middle cervical, thoracic inlet and the intrathoracic tracheal regions, which consisted of 12, 12, nine and 12 tracheal rings, respectively. Fusion of the tracheal rings was especially obvious in the cranial cervical and thoracic inlet regions as a result of neck movements. The diameter and thickness of the tracheal rings are smallest at the thoracic inlet level because the direction of the trachea changes at this point where the thoracic inlet is relatively small and surrounded by bone. The ratios of inner transverse to inner vertical and outer transverse to outer vertical diameters were almost the same, between 1.14 and 1.25 in all regions, which indicated that the trachea is near-circular in shape in the dog. At the thoracic inlet level cross-sectional lumen areas are 7 and 6% smaller than those in the middle cervical and intrathoracic regions, respectively. The thinnest cartilage was seen at the thoracic inlet level where there is a risk of tracheal collapse.

In many organisms, polo kinases appear to play multiple roles during M-phase progression. To provide new insights into the function of the budding yeast polo kinase Cdc5, we generated novel temperature-sensitive cdc5 mutants by mutagenizing the C-terminal noncatalytic polo box domain, a region that is critical for proper subcellular localization. One of these mutants, cdc5-11, exhibited a temperature-sensitive growth defect with an abnormal spindle morphology. Strikingly, provision of a moderate level of benomyl, a microtubule-depolymerizing drug, permitted cdc5-11 cells to grow significantly better than the isogenic CDC5 wild type in a FEAR (cdc Fourteen Early Anaphase Release)-independent manner. In addition, cdc5-11 required MAD2 for both cell growth and the benomyl-remedial phenotype. These results suggest that cdc5-11 is defective in proper spindle function. Consistent with this view, cdc5-11 exhibited abnormal spindle morphology, shorter spindle length, and delayed microtubule regrowth at the nonpermissive temperature. Overexpression of CDC5 moderately rescued the spc98-2 growth defect. Interestingly, both Cdc28 and Cdc5 were required for the proper modification of the spindle pole body components Nud1, Slk19, and Stu2 in vivo. They also phosphorylated these three proteins in vitro. Taken together, these observations suggest that concerted action of Cdc28 and Cdc5 on Nud1, Slk19, and Stu2 is important for proper spindle functions.

Computed tomographic images of the thoracic spine of 13 German shepherd dogs were examined in order to determine the thoracic spine morphometry. Examinations were carried out in the transverse plane both intervertebral and mid-vertebral levels of the each thoracic vertebrae. The dorsoventral and interpedicular diameters of the spinal canal, the dorsoventral and transverse diameters of the vertebral body, the dorsoventral and transverse diameters of the spinal cord and also the cross-section area of the spinal canal were measured. The maximum values were found to be at the level of C7-T1. The shapes of the spinal canal and cord were circular in middle part, the shape became transverse oval in the cranial and caudal parts of the thoracic spine. The most significant correlation between the diameters was found to be in male dogs, except between dorsoventral diameters of the spinal canal and that of the vertebral body and between dorsoventral diameters of the spinal canal and transverse diameters of the vertebral body.

Ten segments of the aorta of the rabbit were studied quantitatively. The thoracic and abdominal aorta of the rabbit were measured from proximal to distal and parallel to the reduced diameter, demonstrating a decreasing thickness of the tunica intima and tunica media that becomes physiologically apparent during adulthood in these commonly used laboratory animals. The ratio of intimal to medial thickness, multiplied by 100, was calculated and found to be between 2.56 and 3.74 for the thoracic aorta and 4.03 and 5.62 for the abdominal aorta of the rabbit. These findings are important for the better understanding of the development of atherosclerosis.