Oxytetracycline as a predisposing condition for chalkbrood in honeybee

Antibiotics, particularly oxytetracycline, have been discussed as a possible predisposing condition in the appearance of chalkbrood in the honeybee (Apis mellifera L.). Nevertheless, the scientific data to support this belief have been insufficient. We have developed a method to study the effects of this antibiotic as a predisposing factor under different circumstances. We conclude that oxytetracycline does not increase the risk of chalkbrood in susceptible worker brood in the short or mid-term.     

Study of Calcium Ion Diffusion in Nixtamalized Quality Protein Maize as a Function of Cooking Temperature

In this report, the effect of temperature on the calcium content of Quality Protein Maize (QPM H-368C) during the nixtamalization process as a function of the steeping time for three cooking temperatures (72, 82, and 92°C) is presented. Also, for the first time, we report in physico-chemical terms the end of the cooking stage during the nixtamalization process that was established when the moisture content in corn kernels reached a value of 36% (w/w) with a lime concentration of 1% (w/v), independent of the cooking temperature. Atomic absorption spectroscopy was used to determine the calcium concentration in the whole kernel and in its different anatomical components (pericarp, endosperm, and germ) as well as in 10% of the outermost layers, the next 10%, and the remaining 80% of the endosperm as a function of the steeping time. It was found that if the cooking temperature increases, the calcium content increases also. For steeping times in the range of 5–7 hr, a relative maximum was found in the calcium contents of 0.24, 0.21, and 0.18% (w/w) in QPM H-368 flours at 92, 82, and 72°C, respectively. Calcium was found in the most external layers in the endosperm and minimum diffusion occurs in the internal 80%. Phosphorous was measured by using UV spectroscopy and the results showed that it remains constant at 0.24% throughout the process. Scanning electron microscopy analysis was used to explain the calcium ion diffusion in the kernel. The physical changes in the pericarp govern the calcium diffusion process.     

Radiographic diagnosis of craniodorsal coxofemoral luxation in standing equids

Radiographic evaluation of the pelvis in standing horses has been used to diagnose fractures of the pelvis, head and greater trochanter of the femur, and luxations of the coxofemoral joint. Coxofemoral luxation injuries are more common in smaller horse breeds and donkeys, but, due to their size, the standing ventrodorsal projection is not possible, as there is insufficient space to place the radiography equipment under the animal's abdomen. The objective of the study was to report the advantages and limitations of the use of an oblique radiographic projection to diagnose unilateral craniodorsal coxofemoral luxation in 3 ponies and a donkey performed with the animals standing under light sedation. All cases had severe unilateral hindlimb lameness and asymmetry of the gluteal region; 2 also had concurrent intermittent upward fixation of the patella. A standing dorsolateral 20–30° ventral oblique radiograph of the affected coxofemoral joint was performed in all cases to obtain a definitive diagnosis. Radiography of the coxofemoral joint in standing ponies and donkeys can be carried out to identify craniodorsal coxofemoral luxation avoiding the need for general anaesthesia.     

Evidence for antibody-catalyzed ozone formation in bacterial killing and inflammation

Recently, we showed that antibodies catalyze the generation of hydrogen peroxide (H2O2) from singlet molecular oxygen (1O2*) and water. Here, we show that this process can lead to efficient killing of bacteria, regardless of the antigen specificity of the antibody. H2O2 production by antibodies alone was found to be not sufficient for bacterial killing. Our studies suggested that the antibody-catalyzed water-oxidation pathway produced an additional molecular species with a chemical signature similar to that of ozone. This species is also generated during the oxidative burst of activated human neutrophils and during inflammation. These observations suggest that alternative pathways may exist for biological killing of bacteria that are mediated by potent oxidants previously unknown to biology.     

Stimulation of bone formation in vitro and in rodents by statins

Osteoporosis and other diseases of bone loss are a major public health problem. Here it is shown that the statins, drugs widely used for lowering serum cholesterol, also enhance new bone formation in vitro and in rodents. This effect was associated with increased expression of the bone morphogenetic protein-2 (BMP-2) gene in bone cells. Lovastatin and simvastatin increased bone formation when injected subcutaneously over the calvaria of mice and increased cancellous bone volume when orally administered to rats. Thus, in appropriate doses, statins may have therapeutic applications for the treatment of osteoporosis.     

Tissue specificity of histone phosphorylation

The incorporation of (32)P-phosphate into histone fractions isolated from normal, hepatectomized, and Novikoff hepatoma-bearing rats was investigated. Varying degrees of phosphorylation were exhibited by different histone fractions. The phosphorylation of histones is tissue specific and appears to be correlated with metabolic cell functions, that is, it decreases with increasing mitotic activity of the cells.     

Arsenic and metals mobility in soils impacted by tailings at Zimapán,México

Purpose

Mining wastes may cause important environmental impacts in soil, water, and air due to their high metals and arsenic contents. The aim of this work was the assessment of the mobility of arsenic and several heavy metals in soils located near different types of tailing heaps in the town of Zimapán, México.

Materials and methods

One hundred twenty soil samples were collected nearby to three tailing heaps, one oxidized presenting a red color (RT), and two with gray wastes (OSM and NSM) but with different age, during the dry and rainy seasons at the surface and to 40 cm depth, as well as to different distances from the deposits. Arsenic, Cd, Cu, Fe, Mn, Pb, V, and Zn total concentrations were determined; in addition, geochemical phase distribution of As, Cu, Mn, and Zn in selected samples was determined by sequential extraction. Concentrations were measured by graphite furnace atomic absorption spectrometry and inductively coupled plasma. To interpret the results, statistical analyses were performed.

Results and discussion

All samples presented high As concentrations reaching more than 50,000 mg kg^?1 close to OSM tailings, although the highest concentrations in the available fractions were measured in NSM impacted soils. Arsenic and metals concentrations exceeded the screening limits recommended for industrial sites. In samples influenced by OSM tailings, most of the elements analyzed were in the residual fraction, whereas in NSM and RT they were mostly in the organic and sulfide fractions and in the Fe and Mn oxides fractions, respectively. Larger concentrations of As and metals than those allowed by the screening values in Canada and the Netherlands were measured in the residential area representing a health threat for the inhabitants and the environment.

Conclusions

Acid mine drainage, water, and wind erosion of tailings have polluted nearby soils. Higher concentrations of As and metals were measured during the rainy season in gray tailings impacted soils and during the dry season in red tailings, showing both deposit types’ different mobility. Elements fractionation in soils depends mainly on tailings characteristics. Low metals and As proportions were found in the fraction with the highest mobility. Metals and arsenic are more stable in soils impacted by gray tailings, mainly in the organic and sulfides and residual fractions, while in RT, most are linked to Fe and Mn oxyhydroxides. Polluted soils in residential areas constitute a health hazard. Remedial actions must be taken to stop the population exposure.

     

Surveillance programme for important equine infectious respiratory pathogens in the USA

The prevalence and epidemiology of important viral (equine influenza virus [EIV], equine herpesvirus type 1 [EHV-1] and EHV-4) and bacterial (Streptococcus equi subspecies equi) respiratory pathogens shed by horses presented to equine veterinarians with upper respiratory tract signs and/or acute febrile neurological disease were studied. Veterinarians from throughout the USA were enrolled in a surveillance programme and were asked to collect blood and nasal secretions from equine cases with acute infectious upper respiratory tract disease and/or acute onset of neurological disease. A questionnaire was used to collect information pertaining to each case and its clinical signs. Samples were tested by real-time PCR for the presence of EHV-1, EHV-4, EIV and S equi subspecies equi. A total of 761 horses, mules and donkeys were enrolled in the surveillance programme over a 24-month study period. In total, 201 (26.4 per cent) index cases tested PCR-positive for one or more of the four pathogens. The highest detection rate was for EHV-4 (82 cases), followed by EIV (60 cases), S equi subspecies equi (49 cases) and EHV-1 (23 cases). There were 15 horses with double infections and one horse with a triple infection. The detection rate by PCR for the different pathogens varied with season and with the age, breed, sex and use of the animal.