Traces of human migrations in Helicobacter pylori populations

Helicobacter pylori, a chronic gastric pathogen of human beings, can be divided into seven populations and subpopulations with distinct geographical distributions. These modern populations derive their gene pools from ancestral populations that arose in Africa, Central Asia, and East Asia. Subsequent spread can be attributed to human migratory fluxes such as the prehistoric colonization of Polynesia and the Americas, the neolithic introduction of farming to Europe, the Bantu expansion within Africa, and the slave trade.     

Identification of active edge sites for electrochemical H2 evolution from MoS2 nanocatalysts

The identification of the active sites in heterogeneous catalysis requires a combination of surface sensitive methods and reactivity studies. We determined the active site for hydrogen evolution, a reaction catalyzed by precious metals, on nanoparticulate molybdenum disulfide (MoS2) by atomically resolving the surface of this catalyst before measuring electrochemical activity in solution. By preparing MoS2 nanoparticles of different sizes, we systematically varied the distribution of surface sites on MoS2 nanoparticles on Au(111), which we quantified with scanning tunneling microscopy. Electrocatalytic activity measurements for hydrogen evolution correlate linearly with the number of edge sites on the MoS2 catalyst.     

Do riparian buffer strips mitigate the impacts of clearcutting on small mammals?

We assessed the impact of clearcutting on small mammals in riparian areas and evaluated riparian buffer strips as a tool for conserving small mammals in managed forests. Over two summers, we trapped small mammals of seven species in riparian areas in southwestern British Columbia, Canada. Communities of small mammals were compared across three different habitat types: (1) clearcut to the stream bank, (2) clearcut with a 30 m riparian buffer strip, and (3) control (no logging). Species richness was significantly lower in clearcuts than in controls and buffers. On clearcut sites, creeping voles were more abundant, but red-backed voles and dusky shrews were less abundant than at the control sites. At sites with riparian buffer strips, both voles were present in numbers similar to those found in controls, but dusky shrews were less common. Significantly more deer mice and creeping voles were infested with bot flies at clearcut sites than at buffer sites, and no animals were infested at any of the control sites. Riparian reserves appear to be useful in reducing the short-term impacts of clearcutting on small mammal communities, though they do not eliminate these impacts altogether.     

Effects of Foliar Fertilization on Incidence of Berry Shrivel and Bunch Stem Necrosis in Vitis vinifera L. CVS ‘Pinot Blanc’ and ‘Zweigelt’

Berry shrivel and bunch stem necrosis are the economically most important physiological disorders of grapevine. The nutritional status of the plant is considered as one of the main elicitors for the occurrence of these disorders. For foliar fertilization trials, two vineyards that had previously been affected by both diseases were selected in Southwest Germany, one with the variety ‘Zweigelt’ and one with Pinot Blanc. By the use of potassium, magnesium, and calcium foliar fertilizers, a rapid increase of different nutrients in the plants should be caused and the effects on the diseases observed. In 2010, no significant differences in the fertilization treatments were found for both varieties. In ‘Pinot Blanc’, significantly more berries were affected by berry shrivel in 2011 in plots treated with calcium fertilizer compared to those treated with potassium and magnesium. Plots with magnesium fertilizer showed significantly less berries affected by berry shrivel than the untreated control.     

Immunohistochemical studies of cone photoreceptors and cells of the inner retina in feline rod-cone degeneration

Previous studies using electroretinography and immunohistochemistry have shown normal cone function and structure in early stages of hereditary rod‐cone degeneration of Abyssinian cats. To further investigate the cone photoreceptors and the inner retina of dystrophic cats, antibodies against green‐ and blue‐sensitive cones and specific cell types of inner retina were used in seven cats with the recessively inherited rod‐cone degeneration, and three normal European short‐haired cats. There was a reduction in number of both types of cones early in the disease. Changes at early stages of disease also occurred among horizontal cells in which there was an extension and a thickening of their lateral processes. The regular configuration of bipolar cells was changed in the more advanced stages of disease and their apical dendrites were lost. Abnormalities were not observed in the amacrine cells and in the ganglion cell layer in any of the present cases. This study shows that the cone system is morphologically abnormal in young cats at an earlier stage of disease than previously shown. The present findings also support the assumption that the inner retina is largely preserved throughout the disease process.     

THE USE OF INTRAPERITONEAL FLUID AS A SIMPLE TECHNIQUE FOR ENHANCING SONOGRAPHIC VISUALIZATION OF THE CANINE PANCREAS

Sonographic evaluation of the pancreas was performed in ten healthy research dogs following intraperitoneal fluid administration. Physiological saline solution was aseptically introduced into the peritoneal cavity of each dog to create an acoustic window that would facilitate sonographic delineation of normal pancreatic tissues. Abdominal ultrasound examinations were performed in all dogs before and after the production of the diagnostic hydroperitoneum. Sonograms of the pancreas and other abdominal organs were scored on the basis of image clarity by experienced and novice ultrasonographers. Statistical analysis was then used to compare the effectiveness of each preparation method. A significant difference (P < 0.05) was established between the scores from the diagnostic hydroperitoneum sonograms and the baseline scans performed without intraperitoneal fluid placement. Sonographic visualization scores for the pancreas and other abdominal organs were increased following production of the diagnostic hydroperitoneum. These results indicate that the technique of diagnostic hydroperitoneum will significantly improve ultrasonographic visualization of the pancreas, and may prove useful in the diagnosis of canine pancreatic disease.     

Electrophysiologic differentiation of homozygous and heterozygous Abyssinian-crossbred cats with late-onset hereditary retinal degeneration

OBJECTIVE: To develop a method to electrophysiologically differentiate heterozygous-carrier Abyssinian-crossbred cats from homozygous-affected Abyssinian-crossbred cats before clinical onset of inherited rod-cone retinal degeneration. ANIMALS: 14 back-crossed Abyssinian-crossbred cats of unknown genotype (homozygous or heterozygous) for inherited rod-cone retinal degeneration, 24 age-matched mixed-breed control cats, 6 age-matched heterozygous Abyssinian-crossbred cats, and 6 homozygous Abyssinian cats. PROCEDURE: Electroretinography (ERG) of heterozygous and homozygous cats revealed differences, especially for scotopic recordings. Frequent ophthalmoscopy and ERG (2 to 5 times; at intervals of 3 to 6 months) of back-crossed cats were performed. Amplitudes and implicit times were analyzed by use of a graphic representation of results. Ratios for amplitudes of the b-waves to amplitudes of the a-waves (b-wave:a-wave) were compared. RESULTS: 8 back-crossed cats had decreased a-wave amplitudes, increased b-wave implicit times, and abnormal ERG waveforms. Values for the b-wave:a-wave for the highest scotopic light intensity were significantly higher for those same 8 cats. CONCLUSIONS AND CLINICAL RELEVANCE: The 8 back-crossed Abyssinian-crossbred cats with abnormal results developed fundus changes over time consistent with disease. A graphic representation of ERG results can be used to differentiate between genotypes prior to funduscopic changes. Values for the b-wave:a-wave ratio provide confirmation. These ERG analyses may be applied clinically in the diagnosis of retinal degenerations in various species. IMPACT FOR HUMAN MEDICINE: Cats with hereditary rod-cone degeneration may be a useful model for comparative studies in relation to retinitis pigmentosa in humans. Similar evaluations of ERG results could possibly be used for humans with suspected generalized retinal degeneration.     

Enhanced expression of cyclooxygenase-2 in glaucomatous dog eyes

Objective Cyclooxygenase‐2 (COX‐2)‐derived prostaglandins (PGs) are shown to play important pathophysiologic roles in various disease states. Recently, the effectiveness of topical PGs in reducing intraocular pressure (IOP) has stimulated further interest in the physiologic function of COX‐2 and PGs in normal and glaucomatous eyes. Therefore, we investigated the cell‐type distribution and expression of COX‐2 in normal and glaucomatous dog eyes. Procedures Using isoform‐specific antibodies, we immunohistochemically evaluated COX‐2 expression in formalin‐fixed and paraffin‐embedded normal (n = 5) and glaucomatous (n = 17) dog eyes. Results In the normal eyes, only minimal COX‐2 immunoreactivity was observed in the ciliary epithelium. In the glaucomatous eyes, COX‐2 expression was further observed in the cornea and corneoscleral limbus. In the cornea, moderate to strong COX‐2 expression was observed in all corneal layers (epithelium, stromal cells and endothelium), with the greatest expression present in the epithelial layer. In the corneoscleral limbus area, COX‐2 immunoreactivity was noted in the stromal cells of sclera, trabecular meshwork and endothelial cells of the angular aqueous plexus. Conclusions Increased expression of COX‐2 in dog glaucomatous eyes suggests that COX‐2‐derived PGs may have a potential role in the pathogenesis of canine glaucoma.     

Severe brain damage after punitive training technique with a choke chain collar in a German shepherd dog

The features of severe ischemic brain damage after strangulation by the owner of a 1-year-old German shepherd dog are described. The dog was disciplined by the owner during training by holding the dog off the ground by his choke chain collar. At first, the dog behaved normally, but he became increasingly ataxic and started circling to the left and showed reduced consciousness. The neurological examination revealed severe disorientation, left lateral pleurothotonus, and circling. The neurological findings were consistent with a multifocal brain lesion. A magnetic resonance imaging scan was performed and showed changes in the T2- and diffusion-weighted images, consistent with severe cerebral edema resulting from ischemia. Because of the severity of the clinical features, the dog was later euthanized. To the author's knowledge, this is the first report of a severe brain ischemia after strangulation in a dog.