Finite element analysis of different loading conditions for implant-supported overdentures supported by conventional or mini implants

The effect of implants’ number on overdenture stability and stress distribution in edentulous mandible, implants and overdenture was numerically investigated for implant-supported overdentures. Three models were constructed. Overdentures were connected to implants by means of ball head abutments and rubber ring. In model 1, the overdenture was retained by two conventional implants; in model 2, by four conventional implants; and in model 3, by five mini implants. The overdenture was subjected to a symmetrical load at an angle of 20 degrees to the overdenture at the canine regions and vertically at the first molars. Four different loading conditions with two total forces (120, 300 N) were considered for the numerical analysis. The overdenture displacement was about 2.2 times higher when five mini implants were used rather than four conventional implants. The lowest stress in bone bed was observed with four conventional implants. Stresses in bone were reduced by 61% in model 2 and by 6% in model 3 in comparison to model 1. The highest stress was observed with five mini implants. Stresses in implants were reduced by 76% in model 2 and 89% increased in model 3 compared to model 1. The highest implant displacement was observed with five mini implants. Implant displacements were reduced by 29% in model 2, and increased by 273% in model 3 compared to model 1. Conventional implants proved better stability for overdenture than mini implants. Regardless the type and number of implants, the stress within the bone and implants are below the critical limits.     

Methylation of KvDMR1 involved in regulating the imprinting of CDKN1C gene in cattle

The CDKN1C gene encodes a cyclin‐dependent kinase inhibitor and is one of the key genes involved in the development of Beckwith–Wiedemann syndrome and cancer. In this study, using a direct sequencing approach based on a single nucleotide polymorphism (SNP) at genomic DNA and cDNA levels, we show that CDKN1C exhibits monoallelic expression in all seven studied organs (heart, liver, spleen, lung, kidney, muscle and subcutaneous fat) in cattle. To investigate how methylation regulates imprinting of CDKN1C in cattle, allele‐specific methylation patterns in two putative differential methylation regions (DMRs), the CDKN1C DMR and KvDMR1, were analyzed in three tissues (liver, spleen and lung) using bisulfite sequencing PCR. Our results show that in the CDKN1C DMR both parental alleles were unmethylated in all three analyzed tissues. In contrast, KvDMR1 was differentially methylated between the two parental alleles in the same tissues. Statistical analysis showed that there is a significant difference in the methylation level between the two parental alleles (P < 0.01), confirming that this region is the DMR of KvDMR1 and that it may be correlated with CDKN1C imprinting.     

Diversity measures in macroinvertebrate and zooplankton communities related to the trophic status of subtropical reservoirs: Contradictory or complementary responses?

Macroinvertebrate communities have been widely used as a tool for assessing the environmental quality of freshwater ecosystems, whereas zooplankton communities have been to some extent neglected. However, the importance of using different indicators to achieve a more comprehensive framework of assessment regarding water quality has been recognized. This study compared estimates of species richness (number of species) and the Shannon–Wiener index for data on macroinvertebrate and zooplankton communities in tropical reservoirs and related them to their trophic state. The trop+hic classification was obtained by applying the Carlson index (1977) modified by Toledo et al. (1983), and the index of the Brazilian Society of the Environmental Technology Agency. The comparative response of the different indicators was analyzed using a series of bivariate correlations (Draftsman’s plot). The results illustrate that diversity measures, namely species richness, responded differently when related to the trophic classification of reservoirs, depending on the community considered. The species richness of zooplankton was positively related to hypereutrophic conditions, due to the higher number of rotifer species, including tolerant generalist species and at the same time, as a result of the exclusion of species from other groups, whereas for macroinvertebrates, species richness was negatively related to hypereutrophic conditions. Melanoides tuberculatus, which exhibits a high tolerance and competitive ability under such conditions, was the dominant species in macroinvertebrate communities, which excluded endemic species and reduced local richness and diversity. The same indicators applied to the zooplankton and macroinvertebrate communities might therefore provide contradictory responses regarding ecological quality assessment in tropical reservoirs, which suggest that zooplankton should be taken into account among the biological quality elements considered in the ecological quality assessment, management, and restoration of water bodies.     

Physiological functions of the TRPM4 channels via protein interactions

Transient Receptor Potential, Melastatin-related, member 4 (TRPM4) channels are Ca²⁺-activated Ca²⁺-impermeable cation channels. These channels are expressed in various types of mammalian tissues including the brain and are implicated in many diverse physiological and pathophysiological conditions. In the past several years, the trafficking processes and regulatory mechanism of these channels and their interacting proteins have been uncovered. Here in this minireview, we summarize the current understanding of the trafficking mechanism of TRPM4 channels on the plasma membrane as well as heteromeric complex formation via protein interactions. We also describe physiological implications of protein-TRPM4 interactions and suggest TRPM4 channels as therapeutic targets in many related diseases. [BMB Reports 2015; 48(1): 1-5]     

PCR-generated conspecific sodium channel gene probe for the house fly.

A segment of the house fly (Musca domestica) homologue of the para (paralytic) sodium channel gene of Drosophila melanogaster was isolated by using mixed sequence oligonucleotide primers in the polymerase chain reaction (PCR). The specificity of the procedure was demonstrated by genomic Southern analysis using the housefly PCR amplification product as a probe and by DNA sequence analysis. The latter showed structural homology to the para gene, but not to the corresponding region of DSC1, another D. melanogaster gene with structural similarity to vertebrate sodium channel genes.     

Modulation of DNA synthesis in aortic smooth muscle cells by dinitrotoluenes

Studies were conducted to determine if in vivo exposure to dinitrotoluenes (DNT), which is associated with circulatory disorders of atherosclerotic etiology in humans, is associated with alterations of vascular smooth muscle cells (SMC) consistent with the atherogenic process. Sprague-Dawley rats (150-180 g) were injected IP for 5 days/week for 8 weeks with 2,4- or 2,6-DNT (0.5, 5, or 10 mg/kg) or medium chain triglyceride (MCT) oil. Histopathologic evaluation of aortae from animals exposed to either isomer showed dysplasia and rearrangement of SMC at all doses tested. Reduced ³H-thymidine incorporation was observed in primary cultures of aortic SMC from DNT-exposed animals relative to vehicle controls. This inhibitory response was maintained for up to two passages in culture after which a significant increase in thymidine incorporation was observed. Exposure of SMC from naive animals to DNT in vitro (1–100 µM) did not alter the extent of thymidine incorporation in cycling or growth-arrested cultures. In contrast, exposure to 2,4- or 2,6-diaminotoluene (DAT) (1–100 µM), carcinogens which share toxic metabolic intermediates in common with DNT, inhibited replicative DNA synthesis and stimulated unscheduled DNA synthesis in cycling and growth-arrested cultures of SMC, respectively. Our results suggest that modulation of DNA synthesis in aortic SMC by DNT metabolites generated in vivo contribute to the development of vascular lesions.Abbreviation DAT diaminotuluene - tDNT technical grade dinitrotoluene - DNT dinitrotoluenes - HU hydroxyurea - IP intraperitoneal - LDH lactate dehydrogenase - MCT oil medium chain triglyceride - NPTC non-protein thiol content - RDS replicative DNA synthesis - SEM standard error of the mean - SMC smooth muscle cells - UDS unscheduled DNA synthesis     

Estimates of relatedness and inbreeding in goose strains from DNA fingerprints

The purpose of this study was to determine if DNA fingerprints (DFPs) could be used to estimate relatedness and inbreeding of strains of geese and to compare three methods of calculating relatedness indices. Strains included a control and selected strain from each of the Chinese and Synthetic (Chinese, Hungarian and Pilgrim) breeds. DFP patterns for each strain were based on individual DNA samples from six females, or on pooled DNA from 15 females different from those used for individual samples. Three relatedness indices were used, namely, genetic distance, modified Rogers distance and band sharing. All relatedness indices showed a closer relationship of strains within than between breeds. Correlation coefficients among relatedness indices were higher based on pooled DNA (r ≥|0·97|) than those based on individual DNA (r ≥|0·741). Inbreeding estimates were higher for selected compared with control strains. It appears that the use of DFPs to estimate relatedness, regardless of index used, and inbreeding can be valuable for studying geese where there is a limited breeding history.     

Detection of leucochimaerism in bovine twins by DNA fingerprinting

Karyotyping and hypervariable genetic markers indicate extensive leucochimaerism between pairs of dizygotic twins in cattle, a result of placental vascular anastomosis. The extent of this chimaerism includes both kind and number of cells exchanged. All heterosexual twin pairs harboured two types of leucocytes, having either XX or XY chromosome pairs, and 30 of 31 pairs of twins shared identical DNA fingerprints. Although chromosome results from skin fibroblasts indicate that some chimaerism occurs in the skin, the low level allows for differentiation of genotypes between twins. The results warrant against the common practice of using blood samples for DNA typing if twinning is not properly documented.