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Mountain Sheep (mountain + sheep)

Distribution by Scientific Domains
Life Sciences75%

Selected Abstracts

Large Interarcuate Spaces in the Cervical Vertebral Column of the Tyrolean Mountain Sheep

ANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 1 2003
E. Turkof
Summary Large interarcual spaces have been described between the arcus vertebrae C5/C6 and C6/C7 in the cervical vertebral column of Nubian goats. This aperture enables direct access to spinal cord and rootlets without the need to perform a hemilaminectomy. The present study was performed in order to determine whether these large interarcual spaces can also be found in the vertebral column of the Tyrolean mountain sheep, as this small ruminant, which is anatomically very similar to the Nubian goat, is frequently used for experimental purposes at the Surgical University Clinic in Austria. The carcasses of 10 sheep (six females, four males; range of age: 2.5,6 years, range of weight: 52,89 kg) were dissected and the vertebral column was exposed. All 10 sheep showed elliptic openings between the fourth cervical and the first thoracal vertebrae. Three sheep had additional openings between the first and the second thoracal vertebrae. All openings were covered solitarily by the ligamentum flavum and under this ligamentum lay the spinal cord without any further osseous or ligamentous protection. These findings are not mentioned in the common textbooks of veterinary anatomy and deserve attention, as they can be a step forward towards non-traumatic experimental surgery on the spinal cord. [source]

Elevation and connectivity define genetic refugia for mountain sheep as climate warms

MOLECULAR ECOLOGY, Issue 14 2006
CLINTON W. EPPS
Abstract Global warming is predicted to affect the evolutionary potential of natural populations. We assessed genetic diversity of 25 populations of desert bighorn sheep (Ovis canadensis nelsoni) in southeastern California, where temperatures have increased and precipitation has decreased during the 20th century. Populations in low-elevation habitats had lower genetic diversity, presumably reflecting more fluctuations in population sizes and founder effects. Higher-elevation habitats acted as reservoirs of genetic diversity. However, genetic diversity was also affected by population connectivity, which has been disrupted by human development. Restoring population connectivity may be necessary to buffer the effects of climate change on this desert-adapted ungulate. [source]

Large Interarcuate Spaces in the Cervical Vertebral Column of the Tyrolean Mountain Sheep

ANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 1 2003
E. Turkof
Summary Large interarcual spaces have been described between the arcus vertebrae C5/C6 and C6/C7 in the cervical vertebral column of Nubian goats. This aperture enables direct access to spinal cord and rootlets without the need to perform a hemilaminectomy. The present study was performed in order to determine whether these large interarcual spaces can also be found in the vertebral column of the Tyrolean mountain sheep, as this small ruminant, which is anatomically very similar to the Nubian goat, is frequently used for experimental purposes at the Surgical University Clinic in Austria. The carcasses of 10 sheep (six females, four males; range of age: 2.5,6 years, range of weight: 52,89 kg) were dissected and the vertebral column was exposed. All 10 sheep showed elliptic openings between the fourth cervical and the first thoracal vertebrae. Three sheep had additional openings between the first and the second thoracal vertebrae. All openings were covered solitarily by the ligamentum flavum and under this ligamentum lay the spinal cord without any further osseous or ligamentous protection. These findings are not mentioned in the common textbooks of veterinary anatomy and deserve attention, as they can be a step forward towards non-traumatic experimental surgery on the spinal cord. [source]

Freeze-dried bone for maxillary sinus augmentation in sheep

CLINICAL ORAL IMPLANTS RESEARCH, Issue 6 2002
Part II: Biomechanical findings
Abstract: This study examines the biomechanical loading capacity of dental implants placed in the posterior maxilla in conjunction with subantral augmentation with either homogeneous demineralized freeze-dried bone from sheep (s-DFDB) or heterogeneous demineralized freeze-dried human bone (h-DFDB) as grafting material in sheep. In 36 adult female mountain sheep, the Schneiderian membrane was elevated extraorally in both maxillary sinuses, and two titanium plasma-flame-sprayed cylindrical implants were inserted in each lateral antral wall. Three groups of 18 maxillary sinuses each were augmented with s-DFDB, h-DFDB and autogenous bone from the illiac crest, respectively. In the remaining 18 sinuses, the subantral hollow space was left empty. Pull-out tests were carried out after intervals of 12, 16 and 26 weeks. The mean pull-out force needed, irrespective of time, was 259.3 N in the empty control group, 356.7 N in the group augmented with autogenous bone, 278.1 N in the test group augmented with h-DFDB and 365.2 N in the group augmented with s-DFDB, revealing no significant difference between the individual groups (P > 0.05). The implants of the group augmented with autogenous bone showed an increase in the mean pull-out force from 223.8 N after 12 weeks to 523.7 N after 26 weeks. The nonaugmented control group yielded values of 248 N after 12 weeks, which rose to 269.8 N at the last test, while the values of the h-DFDB group increased from 275.4 N to 325.4 N. The highest initial pull-out values were obtained in the s-DFDB group. They amounted to 310.5 N after 12 weeks and rose to 481.4 N after 26 weeks. Time thus proved to have a significant influence on the pull-out forces (P = 0.014) with a statistically proven linear trend (P = 0.007). The findings of this experimental study indicate that the use of homogeneous DFDB in one-stage sinus lift procedures results in a mechanical loading capacity of implants comparable to that achieved by autogenous cancellous bone from the iliac crest. In contrast, the use of heterogenous-DFDB resulted in only slightly higher pull-out forces than those observed in the nonaugmented control group after 26 weeks. [source]