The catalytic subunit of DNA-dependent protein kinase regulates proliferation, telomere length, and genomic stability in human somatic cells

The DNA-dependent protein kinase (DNA-PK) complex is a serine/threonine protein kinase comprised of a 469-kDa catalytic subunit (DNA-PK_cs) and the DNA binding regulatory heterodimeric (Ku70/Ku86) complex Ku. DNA-PK functions in the nonhomologous end-joining pathway for the repair of DNA double-stranded breaks (DSBs) introduced by either exogenous DNA damage or endogenous processes, such as lymphoid V(D)J recombination. Not surprisingly, mutations in Ku70, Ku86, or DNA-PK_cs result in animals that are sensitive to agents that cause DSBs and that are also immune deficient. While these phenotypes have been validated in several model systems, an extension of them to humans has been missing due to the lack of patients with mutations in any one of the three DNA-PK subunits. The worldwide lack of patients suggests that during mammalian evolution this complex has become uniquely essential in primates. This hypothesis was substantiated by the demonstration that functional inactivation of either Ku70 or Ku86 in human somatic cell lines is lethal. Here we report on the functional inactivation of DNA-PK_cs in human somatic cells. Surprisingly, DNA-PK_cs does not appear to be essential, although the cell line lacking this gene has profound proliferation and genomic stability deficits not observed for other mammalian systems.     

Use of the EM algorithm to detect QTL affecting multiple-traits in an across half-sib family analysis

QTL detection experiments in livestock species commonly use the half-sib design. Each male is mated to a number of females, each female producing a limited number of progeny. Analysis consists of attempting to detect associations between phenotype and genotype measured on the progeny. When family sizes are limiting experimenters may wish to incorporate as much information as possible into a single analysis. However, combining information across sires is problematic because of incomplete linkage disequilibrium between the markers and the QTL in the population. This study describes formulæ for obtaining MLEs via the expectation maximization (EM) algorithm for use in a multiple-trait, multiple-family analysis. A model specifying a QTL with only two alleles, and a common within sire error variance is assumed. Compared to single-family analyses, power can be improved up to fourfold with multi-family analyses. The accuracy and precision of QTL location estimates are also substantially improved. With small family sizes, the multi-family, multi-trait analyses reduce substantially, but not totally remove, biases in QTL effect estimates. In situations where multiple QTL alleles are segregating the multi-family analysis will average out the effects of the different QTL alleles.     

Serum Calcium Response Following Oral Zinc Oxide Administrations in Dairy Cows

Six non-pregnant cows were allocated into 3 groups. Group 1 comprised a pair of lactating cows, whereas groups 2 and 3 each comprised a pair of non-lactating cows. The cows in groups 1 and 2 were dosed intraruminally by stomach tube with zinc oxide at 120 mg Zn per kg of bodyweight at weekly intervals for a period of 33 days. Each cow received a total of 4 doses of zinc oxide. Group 3 served as non-treated control group. Blood samples were collected from all 6 cows daily. Serum was analysed for concentration of calcium. Within 12–24 h of each zinc oxide administration the serum calcium of the lactating cows dropped dramatically indicating the existence of an antagonistic effect between Zn and Ca. The first Zn induced hypocalcaemic episode in the lactating cows was followed by a rise in serum calcium to a level above the pre-dosing level and above the mean value of the control group. The depth of the hypocalcaemic response decreased with the number of zinc oxide dosings. This effect was explained as a response from the stimulation of the calcium homeostatic mechanisms. In the Zn dosed non-lactating cows responses were similar but less clear. The perspective of these findings is discussed in relation to resistance towards parturient hypocalcaemia.     

Milk Fever Control Principles: A Review

Three main preventive principles against milk fever were evaluated in this literature review, and the efficacy of each principle was estimated from the results of controlled investigations. Oral calcium drenching around calving apparently has a mean efficacy of 50%–60% in terms of milk fever prevention as well as prevention of milk fever relapse after intravenous treatment with calcium solutions. However, some drenches have been shown to cause lesions in the forestomacs. When using the DCAD (dietary cation-anion difference) principle, feeding rations with a negative DCAD (measured as (Na + K) – (Cl + S)) significantly reduce the milk fever incidence. Calculating the relative risk (RR) of developing milk fever from controlled experiments results in a mean RR between 0.19 and 0.35 when rations with a negative versus positive DCAD are compared. The main drawback from the DCAD principle is a palatability problem. The principle of feeding rations low in calcium is highly efficient in milk fever prevention provided the calcium intake in the dry period is kept below 20 g per day. Calculating the relative risk (RR) of developing milk fever from controlled experiments results in a very low mean RR (between 0 and 0.20) (daily calcium intake below versus above 20 g/d). The main problem in implementing the low-Ca principle is difficulties in formulating rations sufficiently low in calcium when using commonly available feeds. The use of large doses of vitamin D metabolites and analogues for milk fever prevention is controversial. Due to toxicity problems and an almost total lack of recent studies on the subject this principle is not described in detail. A few management related issues were discussed briefly, and the following conclusions were made: It is important to supply the periparturient cow with sufficient magnesium to fulfil its needs, and to prevent the dry cows from being too fat. Available information on the influence of carbohydrate intake, and on the effect of the length of the dry period and prepartum milking, is at present insufficient to include these factors in control programmes.     

Risk of Infection with Leishmania spp. in the Canine Population in the Netherlands

The dog is the main reservoir of Leishmania infantum, the causative agent of visceral leishmaniasis (VL) in humans in Southern Europe. In order to identify the risk of dogs from a Leishmania non-endemic area traveling to a Leishmania -endemic area becoming infected and the risk of transmitting infection to humans in non-endemic areas an investigation was performed, in which the results of a questionnaire were combined with the results of a serologic survey.     

Gadopentatic acid affects in vitro proliferation and doxorubicin response in human breast adenocarcinoma cells

Contrasting agents (CAs) that are administered to patients during magnetic resonance imaging to facilitate tumor identification are generally considered harmless. However, gadolinium (Gd) based contrast agents can be retained in the body, inflicting specific cell line cytotoxicity. We investigate the effect of Gadopentatic acid (Gd-DTPA) on human breast adenocarcinoma MCF-7 cells. These cells exhibit a toggle switch response: exposure to 0.1 and 1 mM concentrations of Gd-DTPA enhances proliferation, which is hindered at a higher 10 mM concentration. Proliferation is enhanced when cells transition to 3D morphologies in post confluent conditions. The proliferation dependence on the concentration of CA is absent for Hs 578T and MDA-MB-231 triple negative cell lines. MCF-7 cells reveal a double toggle switch related to the expression of VEGF, which goes through high–low–high downregulation when cells are exposed to 0.1, 1, and 10 mM Gd-DTPA, respectively. Finally, doxorubicin drug response is assessed, which also reveals a double toggle switch behavior, where drug cytotoxicity exhibits a nonlinear dependence on the CA concentration. A toggle switch in cell characteristics that are exposed to 1 mM of Gd-DTPA amplifies the importance of this threshold, affecting several cell behaviors if surpassed. This work emphasizes the important effects that CAs can have on cells, specifically Gd-DTPA on MCF-7 cells, and the implications for cell growth and drug response during clinical and synthetic biology procedures.     

Association analysis between four vitamin D receptor gene polymorphisms and developmental dysplasia of the hip

Developmental dysplasia of the hip (DDH) is a congenital condition characterized by abnormality in acetabulum size and/or shape. The incidence rate of DDH differs between different populations with risk factors including positive family history, breech presentation, sex, firstborn status, side of the hip, mode of delivery and oligohydramnios. It is recognized that DDH has a genetic component that exhibit autosomal dominant patterns. Many candidate genes have been studied and found to be associated with the disease; most of them are normally involved in cartilage development and joint metabolism. In this study, the association of four single-nucleotide polymorphisms (SNPs) (rs731236, rs1544410, rs7975232 and rs2228570) in the vitamin D receptor (VDR) gene was studied by a case–control analysis. The study sample involves 50 cases with confirmed DDH presentation and 50 nonDDH controls. SNPs were genotyped using conventional polymerase chain reaction (PCR) and restriction fragment-length polymorphism (RFLP) techniques. Genotype and allele frequencies were analysed using SPSS software. No significant associations were found between the VDR polymorphisms analysed and DDH. Further work need to be performed using genomewide analysis to elucidate the genetic basis of DDH.     

Bioerosion in the Miocene Reefs of the northwest Red Sea,Egypt

Macroborings provide detailed information on the bioerosion, accretion and palaeoenvironment of both modern and fossil reefs. Dolomitized reefal carbonates in the Um Mahara Formation exhibit an outstanding example of spatially distributed, well‐preserved bioerosion structures in tropical to subtropical syn‐rift Miocene reefs. Ten ichnospecies belonging to five ichnogenera are identified; three belonging to the bivalve‐boring ichnogenus Gastrochaenolites, three attributed to the sponge‐boring ichnogenus Entobia, and four ichnospecies assigned to three worm‐boring ichnogenera Trypanites, Maeandropolydora and Caulostrepsis. The distribution of the reported borings is strongly linked to the palaeo‐reef zones. Two distinctive ichnological boring assemblages are recognized. The Gastrochaenolites‐dominated assemblage reflects shallower‐marine conditions, under water depths of a few metres, mostly in back‐reef to patch‐reef zones of a back‐reef lagoon. The Entobia‐dominated assemblage signifies relatively deeper marine conditions, mostly in reef core of the fringing Miocene reefs. These ichnological assemblages are attributed herein to the Entobia sub‐ichnofacies of the Trypanites ichnofacies. This ichnofacies indicates boring in hard carbonate substrates (such as corals, rhodoliths, carbonate cements and hardgrounds) during periods of non‐sedimentation or reduced sediment input.