Plant virus infection development as affected by heavy metal stress

The work was focused on the investigation of possible dependencies between the development of viral infection in plants and the presence of high heavy metal concentrations in soil. Field experiments have been conducted in order to study the development of systemic tobacco mosaic virus (TMV) infection in Lycopersicon esculentum L. cv. Miliana plants under effect of separate salts of heavy metals Cu, Zn and Pb deposited in soil. As it is shown, simultaneous effect of viral infection and heavy metals in tenfold maximum permissible concentration leads to decrease of total chlorophyll content in experiment plants mainly due to the degradation of chlorophyll a. The reduction of chlorophyll concentration under the combined influence of both stress factors was more serious comparing to the separate effect of every single factor. Plants' treatment with toxic concentrations of lead and zinc leaded to slight delay in the development of systemic TMV infection together with more than twofold increase of virus content in plants that may be an evidence of synergism between these heavy metal's and virus' effects. Contrary, copper although decreased total chlorophyll content but showed protective properties and significantly reduced amount of virus in plants.     

Rotation advancement of the midface by distraction osteogenesis

A wide variety of disease processes produce alteration of midfacial skeletal growth, resulting in moderate-to-severe midface deficiency presenting as retrusion associated with Angle's class III malocclusion. Le Fort III osteotomies with advancement can provide an excellent tool for correction of this deformity. Recently, the corrective procedure of choice for advancement of midfacial segments has been distraction osteogenesis after osteotomy. Straight linear advancement is the most common choice for corrective movement of the midfacial segment, whether accomplished through acute surgical advancement or through the progressive distraction technique. Unfortunately, linear advancement can produce abnormal configurations, both at the nasal root and lateral orbits, regardless of the technique used. Enophthalmos, caused by orbital enlargement, may limit the advancement necessary to achieve class I occlusion.The authors have extended the utility of the Le Fort III procedure and have improved the final outcome by creating a controlled rotation advancement of the midfacial segment using distraction. The application of an existing internal distraction device is modified to control the movement of the midfacial segment in a rotation advancement path. Included in the series were 10 patients with severe midface retrusion secondary to multiple congenital syndromes, along with cleft lip and palate. The ages of the patients ranged from 6 to 14 years. An internal distraction system was used in all cases. Application of the distractor was substantially modified to simplify both fixation and removal and to produce controlled rotation advancement. The team orthodontist determined the final occlusal relationship. Percutaneous distractor drive rods were removed 4 to 6 weeks after active distraction to increase patient comfort. The distractors and all associated hardware were removed after 12 to 16 weeks of consolidation; follow-up periods ranged from 1 to 3 years.By using the modified distractor application to produce rotation advancement, the contour abnormalities at the nasal root and lateral orbit and the enophthalmos produced by linear advancement were eliminated. Significant improvement in facial contour and class I occlusion was obtained in all cases. Complications consisted of near exposure of the device in one patient. Stability has been excellent, with no relapse reported by the orthodontist.Rotational advancement of facial segments by distraction allows successful early intervention in patients with significant midface retrusion. The abnormal nasal root and lateral orbital configurations produced by direct linear advancement are avoided, and a stable and normalized facial configuration is produced.     

Extramedullary hematopoiesis in a case of benign mixed mammary tumor in a female dog: cytological and histopathological assessment

Backgroud  

Extramedullary hematopoiesis (EMH) is defined as the presence of hematopoietic stem cells such as erythroid and myeloid lineage plus megakaryocytes in extramedullary sites like liver, spleen and lymph nodes and is usually associated with either bone marrow or hematological disorders. Mammary EMH is a rare condition either in human and veterinary medicine and can be associated with benign mixed mammary tumors, similarly to that described in this case.     

The effects of electromagnetic radiation of extremely high frequency and low intensity on the growth rate of bacteria Escherichia coli and the role of medium pH

It has been shown that coherent electromagnetic irradiation (EMI) of extremely high frequency (45-53 GHz) or millimeter waves (wavelength 5.6-6.7 mm) of low intensity (flux capacity 0.06 mW/cm2) of Escherichia coli K12, grown under anaerobic conditions during the fermentation of sugar (glucose) for 30 min or 1 h, caused a decrease in their growth rate, the maximum inhibitory effect being achieved at a frequency of 51.8 or 53 GHz. This effect depended on medium pH when the maximal action was determined at pH 7.5. In addition, separate 30-min of 1-h irradiation (frequency 51.8 or 53 GHz) of doubly distilled water or some inorganic ions contained in Tris-phosphate buffer where the cells were transferred induced oppositely directed changes in further growth of these bacteria under anaerobic conditions; irradiation of water caused a decrease in the growth rate of bacteria. A significant change in pH of water (0.5-1.5 unit) was induced by a 30-irradiation at a frequency of 49, 50.3, 51.8, or 53 GHz, when the initial pH value was 6.0 or 8.0, but not 7.5. These results indicate the changes in the properties of water and its role in the effects of EMI of extremely high frequency. The marked effect of EMI on bacteria disappeared upon repeated irradiation for 1 h at a frequency of 51.8 or 53 GHz with an interval of 2 hours. This result indicates some compensatory mechanisms in bacteria.     

Axisymmetric Drop Shape Analysis for Estimating the Surface Tension of Cell Aggregates by Centrifugation

Biological tissues behave in certain respects like liquids. Consequently, the surface tension concept can be used to explain aspects of the in vitro and in vivo behavior of multicellular aggregates. Unfortunately, conventional methods of surface tension measurement cannot be readily applied to small cell aggregates. This difficulty can be overcome by an experimentally straightforward method consisting of centrifugation followed by axisymmetric drop shape analysis (ADSA). Since the aggregates typically show roughness, standard ADSA cannot be applied and we introduce a novel numerical method called ADSA-IP (ADSA for imperfect profile) for this purpose. To examine the new methodology, embryonic tissues from the gastrula of the frog, Xenopus laevis, deformed in the centrifuge are used. It is confirmed that surface tension measurements are independent of centrifugal force and aggregate size. Surface tension is measured for ectodermal cells in four sample batches, and varies between 1.1 and 7.7 mJ/m². Surface tension is also measured for aggregates of cells expressing cytoplasmically truncated EP/C-cadherin, and is approximately half as large. In parallel, such aggregates show a reduction in convergent extension-driven elongation after activin treatment, reflecting diminished intercellular cohesion.     

A 1-year study of osteoinduction in hydroxyapatite-derived biomaterials in an adult sheep model: part II. Bioengineering implants to optimize bone replacement in reconstruction of cranial defects

The present study investigated hydroxyapatite biomaterials implanted in critical-size defects in the calvaria of adult sheep to determine the optimal bioengineering of hydroxyapatite composites to facilitate bone ingrowth into these materials. Five calvarial defects measuring 16.8 mm in diameter were made in each of 10 adult sheep. Three defects were filled with cement paste composites of hydroxyapatite and beta-tricalcium phosphate as follows: (1) 100 percent hydroxyapatite-cement paste, (2) 60 percent hydroxyapatite-cement paste, and (3) 20 percent hydroxyapatite-cement paste. One defect was filled with a ceramic composite containing 60 percent hydroxyapatite-ceramic, and the fifth defect remained unfilled. One year after implantation, the volume of all biomaterials was determined by computed tomography, and porosity and bone replacement were determined using backscatter electron microscopy. Computed tomography-based volumetric assessment 1 year after implantation demonstrated that none of the unfilled cranial defects closed over the 1-year period, confirming that these were critical-size defects. There was a significant increase in volume in both the cement paste and ceramic implants containing 60 percent hydroxyapatite (p < 0.01). There was no significant change in volume of the remaining cement paste biomaterials. Analysis of specimens by backscatter electron microscopy demonstrated mean bone replacement of 4.8 +/- 1.4 percent (mean +/- SEM) in 100 percent hydroxyapatite-cement paste, 11.2 +/- 2.3 percent in 60 percent hydroxyapatite-cement paste, and 28.5 +/- 4.5 percent in 20 percent hydroxyapatite-cement paste. There was an inverse correlation between the concentration of hydroxyapatite and the amount of bone replacement in the cement paste for each composite tested (p < 0.01). Bone replacement in 60 percent hydroxyapatite-ceramic composite (13.6 +/- 2.0 percent) was not significantly different from that in 60 percent hydroxyapatite-cement paste. Of note is that the ceramic composite contained macropores (200 to 300 microm) that did not change in size over the 1-year period. All cement paste composites initially contained micropores (3 to 5 nm), which remained unchanged in 100 percent hydroxyapatite-cement paste. Cement paste implants containing increased tricalcium phosphate demonstrated a corresponding increase in macropores following resorption of the tricalcium phosphate component. Bone replacement occurred within the macropores of these implants. In conclusion, there was no significant bone ingrowth into pure hydroxyapatite-cement paste (Bone Source, Stryker-Leibinger Inc., Dallas, Texas) in the present study. The introduction of macropores in a biomaterial can optimize bone ingrowth for reconstruction of critical-size defects in calvaria. This was demonstrated in both the ceramic composite of hydroxyapatite tested and the cement paste composites of hydroxyapatite by increasing the composition of a rapidly resorbing component such as beta-tricalcium phosphate.     

The influence of low-energy millimeter electromagnetic waves on the stability of DNA molecules in solution

The influence of low-energy millimeter electromagnetic waves on aqueous saline solution of DNA from the liver of healthy rats and rats with sarcoma 45 has been investigated. The characteristic parameters of irradiated and unirradiated DNA, melting temperature, and the range of melting were obtained from melting curves. The duration of exposure did not practically affect the range of melting, while the thermostability of DNA increased; as irradiation duration increased to 90 min, the melting temperature of tumor increased by approximately 1.5 degrees C. It was assumped that the increase in the thermostability of DNA is due to a more effective stabilization of the DNA double helix caused by the dehydration of Na(+)- ions present in the solution.     

The effects of influence of electromagnetic irradiation of millimeter wavelength on background impulse activity of supraoptic nucleus' neurons of rats' hypothalamus

In conditions of acute experiment on white rats anaesthetized by Nembutal (40 mg/kg, intraperitoneally), the registration and analysis of background impulse activity of the supraoptic nucleus neurons of rats' hypothalamus in norm and after electromagnetic irradiation of millimeter wavelength on organism, were carried out. Distributions of neurons by the degree of rhythm regularity, the character of types of dynamics of the following impulse flows, the modality of histograms of interspike intervals, the average discharge frequency, the coefficient of interspike intervals variation, were found out. Changes of the background impulse activity which were related mainly to the changes of the inner structure of registered impulse flows, were revealed. Significant shifts were generally observed in the character of dynamics of neuronal current flows and degree of regularity of the impulse activity. Statistically significant changes of the average frequency of discharges of different frequency range neurons' populations were revealed.