[Eye changes in the merle syndrome in the dog (author's transl)]

In 44 dachshunds of both sexes, reared and held under identical conditions in order to investigate the effects of the merle gene, ophthalmologic examinations were performed. Eleven extreme dapples with a cutaneous depigmentation beyond 50% (homozygous merle animals, MM) exhibited severe defects in variable forms: Microphthalmia and microcornea, microcoria and corectopia, cataracts and colobomas, rudimentary lenses and ectasia of episcleral vessels. In heterozygous merles with a white percentage of coat color beneath 50% (Mm), lacking tapetum lucidum, depigmented retina, papillary anomaly and ectasia of episcleral vessels were stated, as well as in MM-animals, though not in all. These findings are interpreted as obvious gene dosis effects of the incompletely dominant merle gene which is used to produce a characteric harlequin dappling in many breeds of dogs. With the exception of ectasia of episcleral vessels in a few animals, the homozygous well pigmented controls (mm) displayed none of the anomalies mentioned. The meaning of these results for comparactive medicine and animal protection is discussed.

Bone scanning and diagnosis of reflex sympathetic dystrophy secondary to herniated lumbar disks

In two cases, reflex sympathetic dystrophy (RSD) was due to herniated intervertebral disk at L4-5. In both cases, bone scanning with technetium 99m pyrophosphate was of value and its use is recommended in diagnosing mild or early cases of RSD. RSD may be the cause of persisting pain after disk surgery.

[Some mechanical properties of the pig aorta (author's transl)]

In a machine for tensile tests the ultimate strength, stress and strain of the aorta ascendens of 47 female pigs (German landrace) at three different regions of the vessel wall were determined. The animals were fattened under identical conditions in a progeny testing station and slaughtered at the same living weight (102 +/- 2 kg). Weak regressions of body weight and age on parameters measured were nevertheless accounted for. The average elastin content of the aorta ascendens diminished with advancing age but was not significantly correlated to biomechanical properties of the three single samples. Maximum load, stress and modulus of vessel wall segment I (stamped out nearer to the heart) was greater than in sample II. These circumferential segments however exhibited highly stronger biomechanical resistance than sample III, which was stamped longitudinally. In samples I and II there was a negative correlation between thickness of the wall and ultimate tensile stress (N/mm2). Freezing of the material prior to test at -18degrees C for one week resulted in a significant rise in ultimate tensile strength and stress. The meaning of these findings for comparative angiology is discussed.

[The exogenous and genetic components of some vessel wall characteristics in the pig (author's transl)]

Insufficiencies of the circulatory system and increasing transport losses in pigs as well as analogies with respect to atherosclerosis of men and swine were the motives for a broad statistical investigation of important characteristics of the circulatory system in a big population of female German landrace pigs, fattened as progeny groups under identical conditions in a testing station and slaughtered at 100 kg weight. As the most essential results, highly significant seasonal and genetical influences on several traits are to be mentioned, and some meaningful correlations between them: Plasma cholesterol, ceruloplasmin and hematocrit showed markedly lower levels in the summer and increased values in the cold season; the thickness of the intima (aorta and arteria pulmonalis) was quite distinctly greatest in the spring, this phenomenon being almost exactly paralleled by augmented amounts of copper and iron in the aortic wall. Increased heart weights were again found in the cold, decreased ones in the warm seasons. On average, bigger hearts and vessels were accompanied by higher elastin contents of the aorta, but these contents stood in very significant negative correlation to the ash content and the amounts of certain mineral components (Ca, Mg and P) of the vessel wall, especially to the ash percentage of the elastic fibers. This indicates that calcifying and mineralizing processes in the wall obviously take place at the cost of the elastic components. The estimation of heritabilities in half and full sibs revealed with h2 = 60% high henetic influences on the elastin content of the aorta and equally so on the ash percentage of elastic fibers. Future investigations must correlate these findings with direct measurements of biomechanical and rheological properties of the vessels.