Modulation of the tissue reninangiotensin-aldosterone system in dogs with chronic mild regurgitation through the mitral valve

OBJECTIVE: To investigate whether the tissue and plasma renin-angiotensin-aldosterone system (RAAS) is activated in dogs with mild regurgitation through the mitral valve and determine the contribution of chymase and angiotensin-converting enzyme (ACE) to the activation of the RAAS and potential production of angiotensin II during the chronic stage of mild mitral valve regurgitation. ANIMALS: 5 Beagles with experimentally induced mild mitral valve regurgitation and 6 clinically normal (control) Beagles. PROCEDURES: Tissue ACE and chymase-like activities and plasma RAAS were measured and the RAAS evaluated approximately 1,000 days after experimental induction of mitral valve regurgitation in the 5 dogs. RESULTS: Dogs with experimentally induced mitral valve regurgitation did not have clinical signs of the condition, although echocardiography revealed substantial eccentric hyper- trophy. On the basis of these findings, dogs with mitral valve regurgitation were classified as International Small Animal Cardiac Health Council class Ib. Plasma activity of renin and plasma concentrations of angiotensin I, angiotensin II, and aldosterone were not significantly different between dogs with mitral valve regurgitation and clinically normal dogs. Tissue ACE activity was significantly increased and chymase-like activity significantly decreased in dogs with mitral valve regurgitation, compared with values in clinically normal dogs. CONCLUSIONS AND CLINICAL RELEVANCE: The tissue RAAS was modulated without changes in the plasma RAAS in dogs with mild mitral valve regurgitation during the chronic stage of the condition. An ACE-dependent pathway may be a major route for production of angiotensin II during this stage of the condition.     

An outbreak of systemic granulomatous disease in cows with high milk yields

Seven of 92 lactating Holstein cows on a dairy farm developed urticaria with alopecia and decreased milk production, and three of the seven died over the course of 7 to 18 days. Pathologic examination of the three cows, including the two dead and one euthanized cow, revealed that the skin, liver, spleen, kidneys, heart, salivary glands, pancreas, adrenal glands, mammary glands, lymph nodes, and trigeminal ganglia had lymphocytic to lymphogranulomatous inflammation. Inflammation predominated by lymphocytic infiltration was prominent in the heart, pancreas, mammary glands, adrenal gland, and trigeminal ganglia. Severe granulomatous inflammation with multinucleated giant cells was present in the spleen and kidneys. These lesions and their distributions were most similar to those seen in suspected cases of citrus pulp toxicosis and hairy vetch toxicosis. The outbreak of this disease resolved with the elimination of Citrus pulp from the feed. Immunohistochemical detection of lymphocytes and macrophage markers confirmed dramatic hyperplasia of CD3-positive T lymphocytes in these lesions. This strongly suggested that a type 4 hypersensitivity reaction played a role in the development of the lesions.     

Anaplasma marginale infection in a Japanese Black cow 13 years after eradication of Rhipicephalus (Boophilus) microplus in Okinawa, Japan

In October 2007, a 15-year-old Japanese Black cow on Ishigaki Island, Okinawa, Japan, was diagnosed with Anaplasma marginale infection based on clinical symptoms, blood examination, smear observation, 16S rRNA and groEL gene sequence analysis, and the result of a CF test. The cow was introduced into the farm from mainland Japan as a calf in 1993, one year before the eradication of Rhipicephalus (Boophilus) microplus, the main vector of A. marginale in Okinawa Prefecture. It is possible that the cow was first infected with A. marginale as a calf in Ishigaki Island and had been persistently infected since then. This is the first reported clinical case of A. marginale infection of cattle since the eradication of R. microplus in Okinawa Prefecture. Additional analysis of major surface protein 1α amino acid sequences revealed that the A. marginale Okinawa strain presented four new repeat forms which were not seen in other strains. This indicates that the Okinawa strain may be a unique geographical variant of A. marginale.     

Light-chain multiple myeloma in a cat.

A diagnosis of light-chain multiple myeloma was made in an 11-year-old male American Shorthair cat. The cat showed atypical plasma cell infiltration in the bone marrow, biclonal gammopathy caused by polymerization of myeloma protein (M-protein), and Bence-Jones proteinuria. The M-protein in the serum of the cat was analyzed by using 12% sodium dodeyl sulfate (SDS) polyacrylamide gel electrophoresis with Coomassie brilliant blue staining. An intense band with a size of 27 kDa, the size of the immunoglobulin light chain, was clearly observed, whereas the band corresponding to the immunoglobulin heavy chain (59 kDa) was undetectable. The 27-kDa band was confirmed to be an immunoglobulin light chain by Western blotting by using antibodies for feline immunoglobulin. These data suggested that the neoplastic plasma cells produce light chain only, leading to the diagnosis of light-chain multiple myeloma in the cat.     

Necessity of dietary taurine supplementation for preventing green liver symptom and improving growth performance in yearling red sea bream Pagrus major fed nonfishmeal diets based on soy protein concentrate

The necessity of dietary taurine supplementation for preventing green liver symptom and improving growth performance of red sea bream Pagrus major fed nonfishmeal (non-FM) diets was investigated. Yearling red sea bream (initial body weight, 580 g) were fed for 36 weeks on non-FM diets based on soy protein concentrate (SPC) supplemented with taurine at levels of 0%, 0.5%, 1.0%, 1.5%, and 2.0%. Specific growth rate (SGR) and feed conversion ratio (FCR) of fish fed the taurine-unsupplemented SPC diet were markedly inferior. In these fish, incidence of green liver was markedly higher and was accompanied by a decrease of tissue taurine concentration and an increase of hepatopancreatic bile pigment content. The green liver symptom was mainly caused by an increase of hemolysis since the erythrocytes became osmotically fragile due to taurine deficiency. Physiological abnormality and growth performance (SGR and FCR) were markedly improved by taurine supplementation to the SPC diets. These results indicate that dietary taurine supplementation is necessary for yearling red sea bream fed non-FM diet based on SPC to maintain normal physiological condition and growth performance.     

In situ detection of cellular and abnormal isoforms of prion protein in brains of cattle with bovine spongiform encephalopathy and sheep with scrapie by use of a histoblot technique.

To detect prion protein, brains from 5 cattle naturally affected with bovine spongiform encephalopathy (BSE) and 3 sheep naturally affected with scrapie were examined and compared with brains of normal cattle and sheep using a histoblot technique. The technique enabled the in situ distinctive detection of the cellular (PrP(C)) and abnormal (PrP(Sc)) isoforms of the prion protein. In BSE- or scrapie-affected brains, the Prp(C) signal decreased, especially in those areas where the PrP(Sc) signal was detected.     

Vertical Changes in Bacterial Communities in Percolating Water of a Japanese Paddy Field as Revealed by PCR-DGGE

Percolating water was sampled from the plow layer and subsoil layer in a Japanese paddy field, and the bacterial communities were compared together with floodwater by polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) targeting a partial 16S rRNA gene and subsequent sequencing. The number of DGGE bands ranged from 16 to 28 with no significant differences among the sampling sites and times. Only 2 bands were common for the three sources of water samples. DGGE bands specific for the floodwater samples and percolating water samples from the plow layer were identified, while percolating water samples from the subsoil layer did not show specific bands but displayed common bands to those of the floodwater samples (7 bands) and percolating water samples from the plow layer (1 band). Cluster analysis of the DGGE banding patterns showed a distinct clustering in the samples of percolating water from the plow layer and a closer relationship between the others. These results suggest that the bacterial communities in percolating water changed during downward movement through the plow layer and subsoil layer. Sequences of the DGGE bands specific for the samples of percolating water from the plow layer showed a close relationship with anaerobic bacteria such as iron-reducers or uncultured bacterial DNA isolated from environments that are considered to be less oxic. On the other hand, the sequences of the bands specific for the samples of floodwater and percolating water from the subsoil layer showed a close relationship with uncultured bacterial DNA isolated from freshwater environments.     

Influences of organic debris and rice root on the nitrogen fixation in the submerged soil

Abstract

A series of experiments has been conducted on the N2 fixation in the paddy soils by the authors (1–4). The amount of organic substrates for microorganisms and the degree of reduction of the soil are found to be two major factors affecting the N₂-fixing activity of the heterotrophic microorganisms in the submerged soil. Organic debris, rice root and their neighboring soils are identified to be the important micro-sites for the heterotrophic N₂ fixers. The organic debris and the rice root are considered to play dual roles by supplying the organic substances; (1) increase of the population of the heterotrophic N₂ fixers—the amount of nitrogenase, (2) preparation of the reduced conditions favorable for the nitrogenase activity.

However, it is not yet clearly known which of these two roles of the organic substrates is more essential to the N₂-fixing activity in the paddy soil. In addition, it is expected that there must be some differences between the organic debris and rice root in their contribution to the N₂ fixation in the paddy soil.

An experiment was carried out to clarify these problems. Moist soil sample was collected from the plough layer of the paddy field at Central Agric. Exp. Sta. in Konosu City, Saitama Pref., passed through a 5 mm sieve and placed in pots (3 kg moist soil/pot). Ammonium sulfate, calcium superphosphate, and potassium chloride at the rate of 0.4-0.4-0.4 (N-P₂O₅-K₂0) g/pot were incorporated into the soil 7 days before transplanting. Split application of ammonium sulfate at the rates of 0.2 and 0.4 g N/pot were also incorporated at 30 and 41 days after transplanting respectively. These pots were divided into three series; planted (P-series), non-planted (N-series), and non-planted and applied with organic manure (O-series). In case of O-series, 60 g of fairly rotted organic manure was applied to each pot. Each pot of P-series was planted with two 4O-day-old seedlings of rice plant at 7 days after submergence. The Nseries was regarded as a control. Each series was not replicated in this preliminary experiment.     

Molecular structures of gellan gum imaged with atomic force microscopy in relation to the rheological behavior in aqueous systems in the presence or absence of various cations

Aqueous solutions of gellan gum with comparable molecular masses but with different acyl contents were investigated by atomic force microscopy and rheological measurements in the presence or absence of various cations. For a high-acyl sample, no continuous network structures were identified microscopically, except in the presence of Ca (2+), where structural inhomogeneity was the highest in terms of the height distribution of molecular assemblies. Rheological thermal hysteresis between sol-gel transitions was detected in the presence of K (+) and Ca (2+), particularly Ca (2+). The storage modulus at 20 degrees C was larger in the order Na (+) < Ca (2+) < K (+). For a low-acyl sample, continuous network structures were identified in the presence of each cation, involving greater thermal hysteresis than the corresponding data for the high-acyl sample. Structural homogeneity was the highest in the presence of K (+). Thermal hysteresis and elasticity of the system were discussed in terms of continuousness and homogeneity of network structures.     

Phylogenetic positions of Mn<Superscript>2+</Superscript>-oxidizing bacteria and fungi isolated from Mn nodules in rice field subsoils

We isolated manganous ion (Mn²⁺) oxidizing bacteria and fungi from Mn nodules collected from two Japanese rice fields. The phylogenetic position of the Mn-oxidizing bacteria and fungi was determined based on their 16S rDNA and 18S rDNA sequences, respectively. Among 39 bacterial and 25 fungal isolates, Burkholderia and Acremonium strains were the most common and dominant Mn²⁺-oxidizing bacteria and fungi, respectively. Majority of the Mn-oxidizing bacteria and fungi isolated from the Mn nodules belonged to the genera that had been isolated earlier from various environments. Manganese oxide depositions on Mn²⁺-containing agar media by these microorganisms proceeded after their colony developments, indicating that the energy produced from Mn²⁺ oxidation is poorly used for microbial growth.