Hypomagnesemia in 188 Dogs: A Hospital Population-Based Prevalence Study

Magnesium is a divalent cation involved in more than 300 metabolic processes. Magnesium acts as an intracellular regulator of most energy-demanding pathways. Clinical investigation in the human medical field has determined risk factors for hypomagnesemia and its relationship to a number of disease processes. Experimental studies have established the effects of hypomagnesemia in dogs, but little is known of its prevalence, risk factors, or clinical associations in a hospital population of dogs. To study the prevalence, risk factors, and clinical associations of hypomagnesemia in dogs, a retrospective cross-sectional study of dogs admitted to the University of Minnesota Veterinary Teaching Hospital over a 2.5-year period was undertaken. The prevalence of hypomagnesemia in the study population was 6.1% (188 of 3,102 dogs). Using both categorical and continuous variables in a univariate analysis, significant associations with hypomagnesemia were identified and used to construct a multivariate analysis of the relative risk of hypomagnesemia. Results from evaluation of 3,102 dogs indicate that the most significant predictors of hypomagnesemia were albumin ( P ≤ .0001; odds ratio [OR] = 0.2), potassium ( P ≤ .0001; OR = 0.5), total CO₂ ( P ≤.05; OR = 0.9), and blood urea nitrogen concentrations ( P < .0001; OR = 0.9), a diagnosis of cardiovascular disease ( P < .02; OR = 1.9); and being a Collie ( P < .02; OR = 3.9) or German Shepherd Dog ( P < .002; OR = 2.2). These results can be used to better understand and predict hypomagnesemia in dogs.     

Modification of the Pharmacokinetics and Dosage of Cefuroxime by Endotoxin-induced Fever in Buffalo Calves

The effect of endotoxin-induced fever on the pharmacokinetics and dosage regimen of cefuroxime was investigated in buffalo calves following a single intravenous dose of 10 mg/kg body weight. The fever was induced by intravenous administration of E. coli endotoxin at a dose of 1 g/kg body weight. The distribution and elimination half-lives were 0.100 h and 1.82 h, respectively, in healthy and 0.109 h and 2.28 h, respectively, in febrile buffalo calves. About 91% of the administered dose was excreted in the urine within 24 h. There was no effect of fever on the plasma protein binding of cefuroxime. The dosage regimen for intravenous administration of cefuroxime may be reduced in febrile conditions but the probability of this was only 0.3.     

Histamine relaxes constricted trachea and bronchi of horse

Horse trachea and bronchi contracted to slow-reacting substance of anaphylaxis, carbachol, 5-hydroxytryptamine, histamine, 2-methyl-histamine, bradykinin and prostaglandin F₂. Prostaglandins E₁ and E₂, isoprenaline and 4-methylhistamine caused relaxation of carbachol-contracted bronchi. Mepyramine (H₁-blocker) specifically inhibited histamine bronchoconstriction. In the presence of mepyramine, histamine caused relaxation of carbachol-contracted bronchi. Metiamide (H₂-blocker) inhibited histamine bronchorelaxation but not relaxation of the trachea. This suggests (1) the presence of both H₁- and H₂-receptors mediating bronchoconstriction and relaxation respectively (2) the existence of an atypical histamine receptor in the trachea. The study suggests that in equine respiratory hypersensitivity under therapy with classical (H₁) antihistaminics, further release of histamine may exert a beneficial broncholytic effect on airways contracted by other chemical mediators of immediate-type inflammation.     

Rhizosphere soil microbial index of tree species in a coal mining ecosystem

Microbial characterization of the tree rhizosphere provides important information relating to the screening of tree species for re-vegetation of degraded land. Rhizosphere soil samples collected from a few predominant tree species growing in the coal mining ecosystem of Dhanbad, India, were analyzed for soil organic carbon (SOC), mineralizable N, microbial biomass carbon (MBC), active microbial biomass carbon (AMBC), basal soil respiration (BSR), and soil enzyme activities (dehydrogenase, urease, catalase, phenol oxidase, and peroxidase). Among the tree species studied, Aegle marmelos recorded the highest value for MBC (590 mg kg⁻¹), urease (190.5 μg NH₄⁺-N g⁻¹ h⁻¹), catalase (513 μg H₂O₂ g⁻¹ h⁻¹), dehydrogenase (92.3 μg TPF g⁻¹ h⁻¹), phenol oxidase (0.057 μM g⁻¹ h⁻¹) and BSR/AMBC (0.498 mg CO₂-C mg biomass⁻¹ day⁻¹); Tamarindus indica for mineralizable N (69.5 mg kg⁻¹); Morus alba for catalase (513 μg H₂O₂ g⁻¹ h⁻¹) and phenol oxidase (0.058 μM g⁻¹ h⁻¹); Tectona grandis for peroxidase (0.276 μM g⁻¹ h⁻¹), AMBC/MBC (99.4%), and BSR/MBC (0.108 mg CO₂-C mg biomass⁻¹ day⁻¹); Ficus religiosa for AMBC (128.4 mg kg⁻¹) and BSR (12.85 mg CO₂-C kg⁻¹ day⁻¹); Eugenia jambolana for MBC/SOC (8.03%); Butea monosoperma for AMBC/SOC (1.32%) and Azadirachta indica for BSR/AMBC (0.1134 mg CO₂-C mg biomass⁻¹ day⁻¹). Principal component analysis was employed to derive a rhizosphere soil microbial index (RSMI) and accordingly, dehydrogenase, BSR/MBC, MBC/SOC, EC, phenol oxidase and AMBC were found to be the most critical properties. The observed values for the above properties were converted into a unitless score (0–1.00) and the scores were integrated into RSMI. The tree species could be arranged in decreasing order of the RSMI as: A. marmelos (0.718), A. indica (0.715), Bauhinia bauhinia (0.693), B. monosperma (0.611), E. jambolana (0.601), Moringa oleifera (0.565), Dalbergia sissoo (0.498), T. indica (0.488), Morus alba (0.415), F. religiosa (0.291), Eucalyptus sp. (0.232) and T. grandis (0.181). It was concluded that tree species in coal mining areas had diverse effects on their respective rhizosphere microbial processes, which could directly or indirectly determine the survival and performance of the planted tree species in degraded coal mining areas. Tree species with higher RSMI values could be recommended for re-vegetation of degraded coal mining area.     

Saccharin-induced systemic acquired resistance against rust (Phakopsora pachyrhizi) infection in soybean: Effects on growth and development

We examined the effect of saccharin on the systemic acquired resistance (SAR) response of soybean to the fungus Phakopsora pachyrhizi, the causal agent of soybean rust. Plants were grown hydroponically in half-strength Hoagland’s solution and were challenged with the pathogen 1, 5, 10 and 15 d after treatment with 3 mM saccharin applied either as a foliar spray or a root drench at the 2nd trifoliate (V3) and early reproductive (R1) stages. Plants were destructively harvested and assessed for visible rust symptoms 2 wk after inoculation. Mode of saccharin application was a significant factor influencing the severity of rust infection. Saccharin applied as a root drench was more effective than the foliar spray treatment at inducing SAR, with increased resistance observed 1 d after application. Systemic protection against rust infection was still apparent 15 d after application of saccharin as a root drench. In contrast, foliar treatment with saccharin did not increase systemic protection until 15 d after treatment. When systemic protection was induced by the application of saccharin in either manner, there was no significant reduction of plant growth, except when plants were inoculated 15 d after the saccharin application as a root drench at the R1 stage of development.     

Growth, photosynthetic pigments and photosynthetic activity during seedling stage of cowpea (Vigna unguiculata) in response to UV-B and dimethoate

UV-B (0.4 W m⁻²) irradiation and dimethoate (100 and 200 ppm) treatments, singly and in combination, declined the growth, photosynthetic pigment contents and photosynthesis (O₂ evolution and CO₂-fixation) of cowpea (Vigna unguiculata). Contrary to this, low concentration of dimethoate (50 ppm) caused stimulation on these parameters, while together with UV-B it showed inhibitory effects. Carotenoids (Car) showed varied responses. It was found that carbon-fixation (¹⁴CO₂) was more sensitive to both the stresses than photosynthetic oxygen evolution. Photosynthetic electron transport activity was reduced by both the stresses, however, 50 ppm dimethoate besides inhibiting photosystem II (PSII) and whole chain activity, showed slight stimulation in photosystem I (PSI) activity. The individual effect of two stresses on PSII activity was probably due to interruption of electron flow at oxidation side of PSII which extended to its reaction center following simultaneous exposure. A similar trend was also noticed in case of CO₂ liberation (measured as ¹⁴CO₂ release) in light and dark. Results suggest that dimethoate (100 and 200 ppm) and UV-B alone caused heavy damage on pigments and photosynthetic activity of cowpea, leading to the significant inhibition in growth. Further, the interactive effects of both the stresses got intensified. However, low concentration (50 ppm) of dimethoate showed stimulation, but in combination, it slightly recovered from the damaging effect, caused by UV-B.     

Comparative studies on chlorpyrifos and methyl parathion induced oxidative stress in different parts of rat brain: Attenuation by antioxidant vitamins

Organophosphate (OP) pesticides are among the most widely used synthetic chemicals for controlling a wide variety of pests. Chlorpyrifos (o,o′-diethyl-o-3,5,6-trichloro-2-pyridyl phosphorothionate, CPF) is among the leading OP pesticides used extensively throughout the world including India while methyl parathion (o,o-di methyl-o-p-nitrophenyl phosphorothioate, MPT) another OP compound, widely used as insecticide and acaricide to control many biting or sucking pests of agricultural crops. Present study was carried out to compare the chronic toxicity of CPF and MPT, their potential to generate oxidative stress and ameliorating effects of antioxidant vitamins in brain of rats. Results of the present study clearly demonstrated that the oral exposure of CPF or MPT, generated oxidative stress in different parts of rat brain consequently accumulating malondialdehyde (MDA) and 4-hydroxynonanal (4HNE), the two major end products of lipid peroxidation, in all the three brain regions i.e. fore-, mid- and hind-brain. The levels of hydrogen peroxide (H₂O₂) were also increased in all the three brain regions when compared with control. CPF and MPT exposure caused decrease in the levels of reduced glutathione (GSH) and increase in the levels of oxidized glutathione (GSSG) in all the three brain regions. The increase in the levels of MDA, 4HNE, H₂O₂ and GSSG was less pronounced when CPF or MPT was given to the rats fed with a mixture of vitamin A, E and C. The present findings clearly show that oral intake of a mixture of vitamin A, E and C protects the rats from MPT or CPF induced oxidative stress and suggest that this treatment alleviates the toxicity of these pesticides to a greater extent.     

Ration restriction,compensatory growth and pituitary growth hormone gene expression in Labeo rohita

An experiment to investigate the compensatory growth (CG) response of Labeo rohita was conducted in two phases: a first phase (6 weeks) in which triplicate groups of fish were subjected to feed restriction (5, 25, 50 and 75 % of satiation) or satiation feeding (control) and a second phase (6 weeks) of satiation feeding for all treatment groups. CG in body weight occurred in groups which were under moderate feed restriction (50–75 % of satiation) under phase 1, but more severe feed restrictions resulted in lower weight gain. Improved feed conversion ratio (FCR) (1.6 ± 0.05 and 1.9 ± 0.03) relative to control (2.1 ± 0.06) was observed in the fish that displayed CG following moderate feed restriction (50–75 % of satiation). At the end of the experiment, body moisture, lipid and protein content were not significantly different between moderately restricted fish and the control. After the first phase, there was no significant difference in the expression of pituitary growth hormone (GH) gene between groups, but at the end of the experiment, significantly lower GH expression was observed in the fish subjected to a restriction of 25 and 50 % of satiation during phase 1. Exploiting the ability of fishes to undergo CG in terms of weight gain and improved FCR without major changes in body composition can be considered as an effective management practice.