Thawing permafrost can mitigate warming-induced drought stress in boreal forest trees

Perennially frozen soil, also known as permafrost, is important for the functioning and productivity of most of the boreal forest, the world's largest terrestrial biome. A better understanding of complex vegetation-permafrost interrelationships is needed to predict changes in local- to large-scale carbon, nutrient, and water cycle dynamics under future global warming. Here, we analyze tree-ring width and tree-ring stable isotope (C and O) measurements of Gmelin larch (Larix gmelinii (Rupr.) Rupr.) from six permafrost sites in the northern taiga of central Siberia. Our multi-parameter approach shows that changes in tree growth were predominantly controlled by the air and topsoil temperature and moisture content of the active soil and upper permafrost layers. The observed patterns range from strong growth limitations by early summer temperatures at higher elevations to significant growth controls by precipitation at warmer and well-drained lower-elevation sites. Enhanced radial tree growth is mainly found at sites with fast thawing upper mineral soil layers, and the comparison of tree-ring isotopes over five-year periods with different amounts of summer precipitation indicates that trees can prevent drought stress by accessing water from melted snow and seasonally frozen soil. Identifying the active soil and upper permafrost layers as central water resources for boreal tree growth during dry summers demonstrates the complexity of ecosystem responses to climatic changes.

Tree-ring data set for dendroclimatic reconstructions and dendrochronological dating in European Russia

The data set presented represents 15 years of collection. It contains tree-ring width measurements from 64 sites of living trees and ten historical chronologies based on archaeological and construction wood up to year 572 CE, altogether 2909 tree-ring series and more than 450000 measured and cross-dated tree rings. It covers the vast territory of European Russia, including its forested northern and central parts, and the Northern Caucasus mountains. The potential use of these data include climatic reconstructions of regional and hemispheric scale, dendrochronological dating of historical and cultural wood, ecological and remote sensing studies.

Measurement(s)	growth ring
Technology Type(s)	Measurement Device
Factor Type(s)	location
Sample Characteristic - Organism	Pinus sylvestris • Picea abies • Quercus robur • Larix sibirica • Fagus orientalis
Sample Characteristic - Environment	woodland area
Sample Characteristic - Location	European Russia

Investigation of a modified reverse saphenous conduit flap in the dog

This experimental study investigated the feasibility of a modified reverse saphenous conduit flap (RSCF). Modified reverse saphenous conduit flaps were harvested bilaterally in 11 experimental dogs. Each flap was based on preservation of either the cranial or caudal branch of the medial saphenous artery and vein, but not both. In five dogs, flaps were elevated from a medial femoral donor site and subsequently sutured into their normal anatomical positions (orthotopic flap). Four of five orthotopic flaps based on the cranial saphenous vessels and three of five orthotopic flaps based on the caudal saphenous vessels survived in their entirety. Orthotopic flaps demonstrated an “all or none” survival pattern. In the second phase, flaps were elevated bilaterally from a medial femoral donor site and transferred to a metatarsal skin defect using a bridging incision in six dogs (heterotopic flaps). Two of six heterotopic flaps, based on the cranial saphenous vessels and two of six based on the caudal saphenous vessels, survived in their entirety. Three flaps, based on the cranial pedicle and two flaps based on a caudal pedicle, experienced partial survival. One flap based on the cranial pedicle and two flaps based on the caudal pedicle experienced total flop failure. Survival of the modified reverse saphenous conduit flap, as described herein, is inconsistent and, therefore, its use cannot be recommended. Additionally, the results suggest that the reverse saphenous conduit flap should be used with caution in cases where trauma or surgery has embarrassed the integrity of either the cranial or caudal vascular branch.

Gait analysis of dogs with hip dysplasia treated with gold bead implantation acupuncture

A “double blinded” prospective study was undertaken to determine whether gold bead implantation acupuncture alleviates lameness and pain in dogs, affected by moderate to severe hip dysplasia. Nineteen large-breed adult dogs, of various breeds with clinical and radiographic evidence of hip dysplasia, were randomly assigned to the acupuncture or the placebo group. The acupuncture treatment with gold bead implantation was performed by a licensed acupuncturist. Objective data were acquired, in the gait analysis laboratory, using kinetic and kinematic parameters before and at one and three months after treatment. In the acupuncture group there was a decrease in vertical and peak vertical impulse formation at one month, which indicated an increase in lameness, without any significant difference between groups at three months post-treatment.

Subjective data were gathered by radiographs as well as serial complete physical examinations by an experienced clinician and an owner questionnaire, before and at one and three months after treatment. Subjective grading of hip dysplasia radiographs did not show any difference in severity between the two groups. According to the physical examination, one dog in the acupuncture group improved, five stayed the same and three worsened. In the placebo group two dogs improved, four stayed the same and three worsened. According to the questionnaire, three dogs in the acupuncture group improved, four stayed the same and two worsened. In the placebo group three dogs improved and six stayed the same. Serial blood analyses were performed and the results were within normal limits at all times.

Localization of integrin alpha(v)beta3 and vascular endothelial growth factor receptor-2 (KDR/Flk-1) in cutaneous and oral melanomas of dog

Melanomas are common neoplasms of dogs and arise from pigment-producing cells called melanocytes or melanoblasts. Melanomas of skin are often easily cured by surgical excision, but those of oral mucosa are aggressive, metastasize to the regional lymph nodes and lungs, and respond poorly to conventional therapy. Tumor growth is sustained by proliferation of microvessels via a process called angiogenesis. Integrin alpha(v)beta3 is expressed in proliferating but not in quiescent microvessels suggesting a role in angiogenesis. Vascular endothelial growth factor (VEGF) manifests its mitogenic and angiogenic effects mainly via VEGF receptor-2 (VEGFR-2/Flk-1). We conducted this immunocytochemical study to investigate the expression of integrin alpha(v)beta3 and VEGFR-2 in archival and fresh samples from cases of canine melanomas. Results show that integrin alpha(v)beta3 was expressed in 72% and 88% of cutaneous and oral melanomas, respectively, and the expression was restricted to and immediately around the melanocytes and endothelial cells. VEGFR-2 staining of selected cases of melanoma revealed that its expression overlapped with the alpha(v)beta3 integrin. Dual immuno-gold electron microscopy confirmed co-localization of integrin alpha(v)beta3 and VEGFR-2 in melanocytes and endothelial cells. These data demonstrate expression and co-localization of integrin alpha(v)beta3 and VEGFR-2 in cutaneous and oral melanomas of dogs.