Cell lines: Valuable tools or useless artifacts

Cell lines are often used in place of primary cells to study biological processes. However, care must be taken when interpreting the results as cell lines do not always accurately replicate the primary cells. In this article, we will briefly talk about advantages and disadvantages of cell lines and then discuss results using the mouse Sertoli cell line, MSC-1, compared with primary mouse Sertoli cells. MSC-1 cells resemble Sertoli cells morphologically and possess several biochemical markers associated with Sertoli cells. Studies have demonstrated that the function and regulation of retinoic acid receptor α (RARα) is similar between MSC-1 and rat Sertoli cells. However, MSC-1 cells lack some of the immune privilege properties associated with primary Sertoli cells, including survival in animals with a fully functional immune system. Therefore, it has to be kept in mind that cell lines do not behave identically with primary cells and should not be used to replace primary cells. In order to strengthen the findings, key control experiments using primary cells should always be performed

Assessment of DNA damage by 53PB1 and pKu70 detection in peripheral blood lymphocytes by immunofluorescence and high-resolution transmission electron microscopy

Purpose 53BP1 foci detection in peripheral blood lymphocytes (PBLs) by immunofluorescence microscopy (IFM) is a sensitive and quantifiable DNA double-strand break (DSB) marker. In addition, high-resolution transmission electron microscopy (TEM) with immunogold labeling of 53BP1 and DSB-bound phosphorylated Ku70 (pKu70) can be used to determine the progression of the DNA repair process. To establish this TEM method in the PBLs of patients with cancer, we analyzed and characterized whether different modes of irradiation influence the formation of DSBs, and whether accompanying chemotherapy influences DSB formation. Methods We obtained 86 blood samples before and 0.1, 0.5, and 24 h after irradiation from patients (n = 9) with head and neck or rectal cancers receiving radiotherapy (RT; n = 4) or radiochemotherapy (RCT; n = 5). 53BP1 foci were quantified by IFM. In addition, TEM was used to quantify gold-labelled pKu70 dimers and 53BP1 clusters within euchromatin and heterochromatin of PBLs. Results IFM analyses showed that during radiation therapy, persistent 53BP1 foci in PBLs accumulated with increasing numbers of administered RT fractions. This 53BP1 foci accumulation was not influenced by the irradiation technique applied (3D conformal radiotherapy versus intensity-modulated radiotherapy), dose intensity per fraction, number of irradiation fields, or isodose volume. However, more 53BP1 foci were detected in PBLs of patients treated with accompanying chemotherapy. TEM analyses showed that DSBs, indicated by pKu70, were present for longer periods in PBLs of RCT patients than in PBLs of RT only patients. Moreover, not every residual 53BP1 focus was equivalent to a remaining DSB, since pKu70 was not present at every damage site. Persistent 53BP1 clusters, visualized by TEM, without colocalizing pKu70 likely indicate chromatin alterations after repair completion or, possibly, defective repair. Conclusion IFM 53BP1 foci analyses alone are not adequate to determine individual repair capacity after irradiation of PBLs, as a DSB may be indicated by a 53BP1 focus but not every 53BP1 focus represents a DSB

Laboratory Testing and Analysis of Joints for Rigid Pavements

The primary objective of this study was to analyze the concrete pavement system under nonlinear temperature distribution and vehicle wheel loading. The jointed concrete pavement system consists of concrete slabs with transverse and longitudinal joints, dowel bars (across transverse joints), tie bars (across longitudinal joints), subbase and subgrade soil. Under the loading conditions the pavement structural system may fail by cracking of the concrete slab, loss-of-support of slab due to temperature induced curling, closing and opening of joints, and failure of load transfer devices such as dowel bars, etc. In order to understand the cause of these failures or to achieve an economical design, the state of stress in the pavement system should be determined. It is very difficult to predict the stresses accurately in the pavement system with discontinuities and complex support conditions using conventional classical methods. Therefore, this project uses the ANSYS finite element software. A literature review was performed to identify and evolve an accurate finite element model. It was found from this review that there were difficulties in incorporating the dowel-concrete interface, loss-of-support, contact conditions at the joints, nonlinear temperature distribution, etc. Since there has been no systematic comparison between the experiment and theoretical analysis in the past, the present study conducted the following laboratory testing to determine the respective stiffness quantities: (I) Doweled concrete blocks under bending and shear load, (2) Concrete blocks with tie bars under bending and shear load, (3) Concrete blocks with aggregate interlock joints under shear load, and (4) Concrete blocks with sealed joints under shear load The stiffness values derived from these testing procedures is to be used in the evolution of a finite element model for the concrete pavement system. In addition to this, it is recommended that field measurement of temperature distribution through the thickness of the slab be performed. Finally, a full-scale field testing using FWD is also recommended. The test results obtained from this full-scale testing could be used to assess the validity of the finite element model

Fatal Outcome of Disseminated Strongyloidiasis despite Detectable Plasma and Cerebrospinal Levels of Orally Administered Ivermectin

Strongyloides stercoralis affects over 100 million people worldwide. Those people most susceptible to infection are those with an immunocompromising condition, such as cancer or human immunodeficiency virus (HIV). Local disease may spread throughout the body of the host, causing a condition termed disseminated strongyloidiasis. Standard treatment for Strongyloides stercoralis infection is oral ivermectin. We describe a patient with chronic lymphocytic leukemia diagnosed with disseminated strongyloidiasis two weeks after initial presentation. After repeated dosing of oral ivermectin with no clinical response, serum and cerebral spinal fluid (CSF) concentrations of ivermectin were measured to assess absorption. The peak serum concentration of 49.3 ng/mL correlated with a CSF concentration of 0.14 ng/mL. Despite these concentrations, the patient eventually succumbed to multi-system organ failure. We discuss the reasons for treatment failure and explore the utility of measuring ivermectin concentrations

Prosthetic shoulder arthroplasty in patients 40 years or younger: outcomes stratified by diagnosis and surgery

Background The outcomes of patients 50–55 years old or younger undergoing prosthetic shoulder arthroplasty (PSA) may not generalize to younger patients. We report outcomes following PSA in a consecutive series of patients 40 years or younger. We hypothesize that total shoulder arthroplasty (TSA) provides better outcome and durability than resurfacing hemiarthroplasty (RHA). Methods Patients were stratified by diagnosis and surgical procedure performed, RHA or TSA. Active range of motion and self-assessed outcome were evaluated preoperatively and at final follow-up. Results Twenty-nine consecutive PSAs were identified in 26 patients, comprising 9 TSAs and 20 RHAs, with a minimum of 2-year follow-up. Twelve PSAs were performed for chondrolysis. Mean active forward elevation, abduction, external rotation, and internal rotation improved significantly (p<0.001 for all). Mean pain score improved from 6.3 to 2.1, Simple Shoulder Test from 4.0 to 9.0, and American Shoulder and Elbow Surgeons score from 38 to 75 (p<0.001 for all). Patients undergoing RHA and TSA had similar outcomes; but three RHAs required revision, two of these within 4 years of implantation. Four of five patients undergoing revision during the study period had an original diagnosis of chondrolysis. Conclusions PSA in young patients provides substantial improvement in active range of motion and patient reported outcomes irrespective of diagnosis and glenoid management. However, patients undergoing RHA, especially for chondrolysis, frequently require subsequent revision surgery, so that RHA should be considered with caution in young patients and only after shared decision-making and counsel on the risk of early revision to TSA

Population pharmacokinetics of artesunate and dihydroartemisinin following single- and multiple-dosing of oral artesunate in healthy subjects

<p>Abstract</p> <p>Background</p> <p>The population pharmacokinetics of artesunate (AS) and its active metabolite dihydroartemisinin (DHA) were studied in healthy subjects receiving single- or multiple-dosing of AS orally either in combination with pyronaridine (PYR) or as a monotherapy with or without food.</p> <p>Methods</p> <p>Data from 118 concentration-time profiles arising from 91 healthy Korean subjects were pooled from four Phase I clinical studies. Subjects received 2-5 mg/kg of single- and multiple-dosing of oral AS either in combination with PYR or as a monotherapy with or without food. Plasma AS and DHA were measured simultaneously using a validated liquid chromatography- mass spectrometric method with a lower limit of quantification of 1 ng/mL for both AS and DHA. Nonlinear mixed-effect modelling was used to obtain the pharmacokinetic and variability (inter-individual and residual variability) parameter estimates.</p> <p>Results</p> <p>A novel parent-metabolite pharmacokinetic model consisting of a dosing compartment, a central compartment for AS, a central compartment and a peripheral compartment for DHA was developed. AS and DHA data were modelled simultaneously assuming stoichiometric conversion to DHA. AS was rapidly absorbed with a population estimate of absorption rate constant (Ka) of 3.85 h^-1. The population estimates of apparent clearance (CL/F) and volume of distribution (V2/F) for AS were 1190 L/h with 36.2% inter-individual variability (IIV) and 1210 L with 57.4% IIV, respectively. For DHA, the population estimates of apparent clearance (CLM/F) and central volume of distribution (V3/F) were 93.7 L/h with 28% IIV and 97.1 L with 30% IIV, respectively. The population estimates of apparent inter-compartmental clearance (Q/F) and peripheral volume of distribution (V4/F) for DHA were 5.74 L/h and 18.5 L, respectively. Intake of high-fat and high-caloric meal prior to the drug administration resulted in 84% reduction in Ka. Body weight impacted CLM/F, such that a unit change in weight resulted in 1.9-unit change in CLM/F in the same direction.</p> <p>Conclusions</p> <p>A novel simultaneous parent-metabolite pharmacokinetic model with good predictive power was developed to study the population pharmacokinetics of AS and DHA in healthy subjects following single- and multiple-dosing of AS with or without the presence of food. Food intake and weight were significant covariates for Ka and CLM/F, respectively.</p

Mass measurements of very neutron-deficient Mo and Tc isotopes and their impact on rp process nucleosynthesis

The masses of ten proton-rich nuclides, including the N=Z+1 nuclides 85-Mo and 87-Tc, were measured with the Penning trap mass spectrometer SHIPTRAP. Compared to the Atomic Mass Evaluation 2003 a systematic shift of the mass surface by up to 1.6 MeV is observed causing significant abundance changes of the ashes of astrophysical X-ray bursts. Surprisingly low alpha-separation energies for neutron-deficient Mo and Tc are found, making the formation of a ZrNb cycle in the rp process possible. Such a cycle would impose an upper temperature limit for the synthesis of elements beyond Nb in the rp process.Comment: Link to online abstract: http://link.aps.org/doi/10.1103/PhysRevLett.106.12250

Iptakalim attenuates self-administration and acquired goal-tracking behavior controlled by nicotine

Iptakalim is an ATP-sensitive potassium channel opener, as well as an a4b2-containing nicotinic acetylcholine receptor (nAChR) antagonist. Pretreatment with iptakalim diminishes nicotine-induced dopamine (DA) and glutamate release in the nucleus accumbens. This neuropharmacological profile suggests that iptakalim may be useful for treatment of nicotine dependence. Thus, we examined the effects of iptakalim in two preclinical models. First, the impact of iptakalim on the interoceptive stimulus effect of nicotine was evaluated by training rats in a discriminated goal-tracking task that included intermixed nicotine (0.4 mg/kg, SC) and saline sessions. Sucrose was intermittently presented in a responseindependent manner only on nicotine sessions. On intervening test days, rats were pretreated with iptakalim (10, 30, 60 mg/kg, IP). Results revealed that iptakalim attenuated nicotine-evoked responding controlled by the nicotine stimulus in a dose-dependent manner. In a separate study, the impact of iptakalim on the reinforcing effects of nicotine was investigated by training rats to lever-press to selfadminister nicotine (0.03 mg/kg/infusion). Results revealed that pretreatment with iptakalim (1, 3, 6 mg/kg, IV) decreased nicotine intake (i.e., less active lever responding). Neither behavioral effect was due to a non-specific motor effect of iptakalim, nor to an ability of iptakalim to inhibit DA transporter (DAT) or serotonin transporter (SERT) function. Together, these finding support the notion that iptakalim may be an effective pharmacotherapy for increasing smoking cessation and a better understanding of its action could contribute to medication development

Rapid communication A rapid and reversible change in dopamine transporters induced by methamphetamine

Abstract Because high doses of methamphetamine promote free radical formation, and striatal dopamine transporters are rapidly inactivated by oxidative events, we determined the effect of a single high dose of methamphetamine on dopamine transporter activity in striatal synaptosomes. One hour after methamphetamine administration, dopamine uptake decreased by 48%. This dramatic decline was totally reversed by 24 h after treatment. These findings suggest that methamphetamine reversibly decreases dopamine transporter activity by oxidative mechanisms