Two fundamentally different processes of rocky planet formation exist, but it is unclear which one built the terrestrial planets of the solar system. They formed either by collisions among planetary embryos from the inner solar system or by accreting sunward-drifting millimeter-sized “pebbles” from the outer solar system. We show that the isotopic compositions of Earth and Mars are governed by two-component mixing among inner solar system materials, including material from the innermost disk unsampled by meteorites, whereas the contribution of outer solar system material is limited to a few percent by mass.
View Article and Find Full Text PDFCalcium-aluminum-rich inclusions (CAIs) are the oldest dated materials that provide crucial information about the isotopic reservoirs present in the early Solar System. For a variety of elements, CAIs have isotope compositions that are uniform yet distinct from later formed solid material. However, despite being the most abundant metal in the Solar System, the isotopic composition of Fe in CAIs is not well constrained.
View Article and Find Full Text PDFUltrasound imaging was used to investigate vastus medialis (VM) architecture in 10 males and 10 females at different knee angles. Increase in muscle thickness occurs predominantly when the knee angle is changed from 0° (full extension) and 45° (p < 0.05); increases in VM pennation angle can be predominantly observed between 45° and 90° (p < 0.
View Article and Find Full Text PDFKey Points: The oxygen cost of breathing represents a significant fraction of total oxygen uptake during intense exercise. At a given ventilation, women have a greater work of breathing compared with men, and because work is linearly related to oxygen uptake we hypothesized that their oxygen cost of breathing would also be greater. For a given ventilation, women had a greater absolute oxygen cost of breathing, and this represented a greater fraction of total oxygen uptake.
View Article and Find Full Text PDFRespir Physiol Neurobiol
September 2014
The oxygen cost of exercise hyperpnea (V˙(O2 RM)) has been quantified using a variety of techniques with inconsistent findings. Between-study variation relates to poor control of breathing patterns and lung mechanics. We developed a methodology allowing precise matching of exercising WOB in order to estimate V˙(O2 RM).
View Article and Find Full Text PDFThe eye is a unique sensory structure, which must be evaluated for toxicity to determine the safety of drugs, industrial chemicals, and consumer products. Changes in the structure and/or function of ocular tissues following systemic administration of a potential new drug in preclinical animal models can result in significant delays in the development of a new therapeutic and in some cases lead to termination of the development. The ability to detect and characterize ocular toxicity in preclinical models and to predict risk in patients is critically dependent on the preclinical testing strategy, the availability and use of state-of-the-art ocular safety assessment tools, and the knowledge of drug mechanism of action and the current regulatory environment.
View Article and Find Full Text PDFBackground: Excessive dermal scarring is characterized by an overabundant deposition of extracellular matrix caused by fibrosis. The purpose of this study was to modify a rodent model of cutaneous healing for use in the development of compounds to minimize scarring, and to test the model with a small molecule inhibitor of transforming growth factor-β type I receptor, activin receptor-like kinase 5, because this class of inhibitors has been demonstrated to be effective in minimizing fibrosis in other organs.
Methods: The rodent model of cutaneous healing consists of uniform full-thickness incisional dermal wounds in rats.
Int J Physiol Pathophysiol Pharmacol
March 2010
Various subtypes of the acid sensing ion channel have been detected in the retina of rodents and other mammalian species, but the functional importance of this finding is not clearly understood. The purpose of the study was to determine if retinal degeneration was present in ASIC1a-/- mice. The eyes of ASIC1a-/- mice, heterozygote ASIC1a+/- mice, and wild type ASIC1a+/+ mice that were 5 or 22-27 weeks old were processed by routine histotech-nological methods and examined for histologic changes in the retina and other portions of the eye.
View Article and Find Full Text PDFThe ability to predict ocular side effects of systemically delivered drugs is an important issue for pharmaceutical companies. Although animal models involving standard clinical ophthalmic examinations and postmortem microscopic examinations of eyes are still used to identify ocular issues, these methods are being supplemented with additional in silico, in vitro, and in vivo techniques to identify potential safety issues and assess risk. The addition of these tests to a development plan for a potential new drug provides the opportunity to save time and money by detecting ocular issues earlier in the program.
View Article and Find Full Text PDFObjective: To describe the microscopic features and lineage of proliferating/infiltrating pigmented cells in ocular melanosis of Cairn Terriers. Animals studied Forty-nine globes removed from 45 Cairn Terriers with ocular melanosis and three globes from control dogs were available for microscopic examination.
Procedures: All globes were examined histologically, eight affected and three control globes were also examined by immunohistochemistry, and three affected and three control globes by transmission electron microscopy.
Cyclooxygenase isoenzymes (COX-1 and -2) catalyze the conversion of arachidonic acid to prostaglandins (PGs) and play a significant role in the health and disease of the eye. Experimental animal models of ocular diseases have been used to assess the effects of the selective COX inhibitors (COXIBs), and nonselective, nonsteroidal anti-inflammatory drugs (ns-NSAIDs) are currently employed in the management of various ophthalmic conditions. This paper provides a review of the comparative expression of COX-1 and COX-2 in the eye under normal and pathologic conditions, including the pathophysiologic role of PGs, and the effects of ns-NSAIDs and selective COX-2 inhibitors in the treatment of ophthalmic conditions.
View Article and Find Full Text PDFContemp Top Lab Anim Sci
May 2005
A female, wild-caught, rhesus macaque (Macaca mulatta), in captivity for 23 years and estimated to be older than 26 years, had an 8-year history of progressive spinal curvature. Scoliosis was initially noted 1 year after a therapeutic bilateral ovariectomy to treat endometriosis. Eight years after the initial diagnosis, the curvature had progressed to a structural (nonflexible), lumbar scoliosis with a curvature to the left and a structural thoracolumbar kyphosis.
View Article and Find Full Text PDFScandals have dominated newspaper headlines, bringing corporate directors under increasing scrutiny. These issues continue to elicit public outrage about wrongdoing and ultimately resulted in standards for for-profit corporate board members through the enactment of the Sarbanes Oxley Act in 2002. Although all board members must address corporate responsibility issues, directors of health care organizations also have responsibilities unique to the health care industry that must be met in relation to corporate compliance requirements.
View Article and Find Full Text PDFErgot alkaloids are-synthesized by fungi of the Claviceps family that infect rye as well as other cereals and grains. Since a portion of the ranch mink diet is cereal, mink are at a risk of being exposed to ergot alkaloids. This study was performed to determine the reproductive toxicity of ergot alkaloids derived from ergot-contaminated oats in mink.
View Article and Find Full Text PDFObjective: To describe the clinical and histological appearance of persistent fetal intraocular vasculature in a colony of ferrets. Design Prospective study.
Animals Studied: Eighty-six European ferrets (Mustela putorius).
Thirty-six formalin-fixed, paraffin-embedded enucleated globes from cats with a diagnosis of diffuse anterior uveal melanoma were obtained. Sections of tumor were excised, deparaffinized, and subjected to nested polymerase chain reaction (PCR) to identify proviral DNA sequences from the feline leukemia virus (FeLV)-feline sarcoma virus (FeSV; 36 eyes), and the feline immunodeficiency virus (FIV; 18 eyes). All samples tested were negative for FIV DNA.
View Article and Find Full Text PDFOBJECTIVE: To determine the incidence and describe ocular abnormalities in a cross-section of the population of Rocky Mountain Horses. Design: Prospective study. Animals: Five-hundred and fourteen Rocky Mountain Horses.
View Article and Find Full Text PDFMature female natural dark mink (Mustela vison) were fed 0.0006 (control), 0.016, 0.
View Article and Find Full Text PDFIn this report we describe the lesions produced by the protozoal organism, Toxoplasma gondii, in the eyes and brain of the common yellow canary (Serinus canaria). Nine of 15 birds in a flock were affected with blindness, which developed over a 3-mo span, and two birds developed torticollis. Microscopic alterations within the eye consisted of a nonsuppurative chorioretinitis with large numbers of macrophages that contained the tachyzoite form of T.
View Article and Find Full Text PDFPrevious research has shown that ingestion of 3,3',4,4',5-pentachlorobiphenyl (PCB 126) by juvenile mink (kits) caused a lesion in the mandible and maxilla that consisted of proliferation of sQuamous epithelium in the periodontal ligament, osteolysis of adjacent alveolar bone, and loose and displaced teeth. Similar, but less severe changes, developed in adult mink fed 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). The present study was conducted to compare similarities and differences of the lesion within the jaws of mink fed these 2 polyhalogenated hydrocarbons.
View Article and Find Full Text PDFBackground: Pet dogs and men share a vulnerability for the development of prostate carcinoma. The purpose of this study was to further characterize the clinical and pathologic features of spontaneous canine prostate carcinoma.
Methods: A multiinstitutional, retrospective study was conducted using 76 dogs with prostate carcinoma that underwent postmortem evaluation.
This report characterizes squamous cell proliferation in young farm mink (Mustela vison) fed a diet supplemented with 0.024 ppm 3,3',4,4',5-pentachlorobiphenyl (polychlorinated biphenyl [PCB] congener 126). One to 2 months of dietary exposure to PCB 126 resulted in gross lesions of the upper and lower jaws consisting of mandibular and maxillary nodular proliferation of the gingiva and loose teeth.
View Article and Find Full Text PDFThe maxilla and mandible from 2 adult female mink fed 5.0 ppb 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) for 6 mo were grossly unremarkable, but histologically had nests of squamous epithelium within the periodontal ligament. There was osteolysis of the adjacent alveolar bone.
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