Rapid Generation of Human Neuronal Cell Models Enabling Inducible Expression of Proteins-of-interest for Functional Studies

CRISPR-Cas9 technology has transformed the ability to edit genomic sequences and control gene expression with unprecedented ease and scale. However, precise genomic insertions of coding sequences using this technology remain time-consuming and inefficient because they require introducing adjacent single-strand cuts through Cas9 nickase action and invoking the host-encoded homology-directed repair program through the concomitant introduction of large repair templates. Here, we present a system for the rapid study of any protein-of-interest in two neuronal cell models following its inducible expression from the human AAVS1 safe harbor locus. With lox-flanked foundation cassettes in the AAVS1 site and a tailor-made plasmid for accepting coding sequences-of-interest in place, the system allows investigators to produce their own neuronal cell models for the inducible expression of any coding sequence in less than a month. Due to the availability of preinserted enhanced green fluorescent protein (EGFP) coding sequences that can be fused to the protein-of-interest, the system facilitates functional investigations that track a protein-of-interest by live-cell microscopy as well as interactome analyses that capitalize on the availability of exquisitely efficient EGFP capture matrices.

Predictors of 1-year mortality in adult lung transplant recipients: a systematic review and meta-analysis

BACKGROUND

Upon surviving the first year post-lung transplantation, recipients can expect a median survival of 8 years. Within the first year, graft failure and multi-organ failure (possibly secondary to graft failure) are common causes of mortality. To better understand the prognosis within the first year, we plan on conducting a systematic review and meta-analysis of observational studies addressing the association between the patient, donor, and transplant operative factors and graft loss 1-year post-lung transplant.

METHODS

We searched MEDLINE, Embase, Cochrane Database of Systematic Reviews, Cochrane Central Register, and PubMed supplemental for non-MEDLINE records for observational studies identifying independent risk factors for early mortality (1 year) in adult lung transplant recipients. We plan on including cohort studies and secondary analyses of randomized controlled trials studying adult lung transplant recipients undergoing their first lung transplant, without any simultaneous organ transplant. We will conduct a random-effects meta-analysis that pools the effect estimates from all eligible studies to obtain a summary estimate and confidence interval for all independent non-therapeutic factors identified in the primary studies.

DISCUSSION

The results from this study may inform future guidelines on the selection of candidates and donors for transplantation and predictive model development and inform the decision-making process that the physician and patient undertake together. Furthermore, through the conduction of this review, we can identify the limitations with the current best evidence, which will encourage the need for studies with a better methodology to reassess the predictors of mortality.

Determinants of success and failure of EMLA

Although EMLA is known to be an effective topical anesthetic, its rate of success is unknown. Indeed, researchers have suggested that EMLA may fail with young and apprehensive children. Therefore, the objectives of this study were to assess EMLA's rate of success as well as factors which predict success. A double-blind, placebo-controlled design was utilized. The sample included 258 children and adolescents aged 5-18 years who were having venipuncture or intravenous (i.v.) cannulation. After having their anxiety assessed, subjects were randomly assigned to have EMLA or placebo applied over the procedure site for 90 min. The visual analogue scale was used to assess pain caused by removal of the semi-permeable dressing and by the procedure. Other information that was collected included: duration of drug application, interval between drug removal and procedure, skin changes at bandage and drug sites and rated difficulty of the procedure. EMLA was successful 84% of the time for venipuncture and 51% of the time for i.v. cannulation. Factors which predicted success of EMLA included type of procedure, duration of drug application and anxiety. EMLA was less successful for i.v. cannulation compared to venipuncture even with duration of drug application controlled. Those who had a poor outcome were more anxious than those with a good outcome. Age of child was not a factor. Strategies for improving efficient use of EMLA were recommended.

In vitro recovery of carbamazepine from ensure

The in vitro recovery of three different dosage forms of carbamazepine (CBZ) when dispersed in gastric or intestinal fluids, in the presence or absence of Ensure was determined. An equivalent of 1 mg of pure CBZ from Tegretol 200 mg of conventional tablets, chewtablets of Tegretol 200-mg and Apo-carbamazepine (200-mg tablets) were dispersed in five dissolution mediums (0.5 ml of Ensure; 0.5 ml of Ensure and 1.0 ml of gastric fluid; 1.0 ml of gastric fluid; 0.5 ml of Ensure and 1.0 ml of intestinal fluid; and 1.0 ml intestinal fluid) and mixed for 1 hr and filtered. The filtrates were then assayed for CBZ using a UV spectrophotometer. The mean recoveries of CBZ for all dosage forms in the various dissolution mediums were: Ensure/gastric fluid, 85%; gastric fluid, 75%, Ensure/intestinal fluid, 59%; intestinal fluid, 79%; and Ensure, 58%. The differences in CBZ recovery from gastric or intestinal fluid, in the presence or absence of Ensure were found to be statistically significant (p less than 0.05). The difference in dosage forms were statistically not discernible. The significant differences observed in recoveries of CBZ due to Ensure warrants an in vivo study to realize the clinical implication of administering CBZ with Ensure.

A survey of parenteral nutrition programs

A questionnaire on parenteral nutrition (PN) programs was sent to Canadian hospital pharmacy directors in a random sample of 100 hospitals. The intent was to obtain information about the existing status of PN committees, PN teams, PN pharmacists, and the environment in which they function. Sixty-seven of the 74 respondents had PN programs. PN protocols were approved in 85 percent of the hospitals; and PN committees existed in 60 percent of the hospitals. Ten hospitals had multidisciplinary PN teams, with pharmacists on each team. Most of the hospitals required routine standardized laboratory tests for PN patients; but only 34 percent of the hospitals had developed monitoring forms. Canadian pharmacists have made progress in the area of PN, however, there are still opportunities for pharmacist involvement in the clinical areas of PN therapy.

Vitamin K1 increases sister chromatid exchange in vitro in human leukocytes and in vivo in fetal sheep cells: a possible role for "vitamin K deficiency" in the fetus

The levels of the vitamin K-dependent clotting factors are markedly lower in the human fetus and newborn than in older infants and adults. Direct measurement of vitamin K1 in cord plasma records low or undetectable levels. This phenomenon, although the norm, is referred to as vitamin K deficiency and is a significant risk factor for hemorrhage in the fetus and newborn. Sister chromatid exchange (SCE), which may be used as an index of mutagenic activity, was assayed in cultured leukocytes of placental and adult blood following phytohemagglutinin stimulation. The mean number of SCEs per metaphase in human placental blood was 3.32 +/- SE 0.219 as compared with levels of 5.13 +/- SE 0.273 in young adults (p less than 0.01), and in the presence of added vitamin K1 at a concentration of 1 X 10(-6) M the SCE increased significantly in both adult and placental cells. In vitro SCE dose response curves to K1 in the blood of fetal and maternal sheep were obtained. When five fetal sheep were given 1 mg of K1 by catheter into the femoral vein the SCE increased from 3.94 +/- SE 0.15 preinjection to 5.38 +/- SE 0.23 at 24 h postinjection (p less than 0.01). In the pretreatment fetal sheep, serum vitamin K1 was below detectable levels in all seven animals in which it was assayed and reached levels as high as 0.3 X 10(-6) M 1 h post-K1 injection. The low level of K1 in the fetus may in fact confer some biological advantage by reducing the risk of mutagenic events during a period of rapid cell proliferation.

Vitamin K as a regulator of benzo(a)pyrene metabolism, mutagenesis, and carcinogenesis. Studies with rat microsomes and tumorigenesis in mice

Vitamin K3 inhibits the conversion of benzo(a)pyrene to its more polar metabolites in an in vitro rat liver microsomal system. Vitamin K3 also inhibits benzo(a)pyrene metabolism in rat liver fragments and reduces its mutagenicity in the Ames test. Higher concentrations of vitamin K3 are required to comparably reduce benzo(a)pyrene metabolism when the microsomal system has been induced with 3-methylcholanthrene. High pressure liquid chromatography analysis of the products of benzo(a)pyrene metabolism shows a uniform reduction of all the metabolic products. When tumors were induced in ICR/Ha female mice by the intraperitoneal injection of benzo(a)pyrene, those mice given vitamin K3 before or both before and after benzo(a)pyrene had a slower rate of tumor appearance and tumor death rate as compared with those receiving benzo(a)pyrene alone. However, vitamin K1 increased the rate of tumor death while vitamin K deprivation and warfarin decreased the rate of tumor appearance and death in benzo(a)pyrene-injected mice. These studies indicate that vitamin K3 is an inhibitor of aryl hydrocarbon hydroxylase and reduces the carcinogenic and mutagenic metabolites in vitro, and inhibits benzo(a)pyrene tumorigenesis in vivo. That vitamin K1 enhances the benzo(a)pyrene effect while warfarin and vitamin K deficiency inhibit benzo(a)pyrene tumorigenesis indicates that vitamin K1, vitamin K deprivation, or possibly blockade of its metabolic cycle also modulates benzo(a)pyrene metabolism in vivo but by a mechanism or at a site different from the vitamin K3 effect. The vitamin K series should be considered as capable of serving a regulatory function in the metabolism of benzo(a)pyrene and possibly other compounds metabolized through the mixed function oxidase system.

Effects of conjugated and nonconjugated antithymocyte globulin and trenimon on T lymphocytes and skin graft rejection

These studies were undertaken to investigate the use of a technique for "homing" of an alkylating agent to lymphocytes as an immunosuppressive approach to inhibit allograft rejection. Trenimon (Tr) was bound covalently to antithymocyte globulin (ATG) and the effects of the complex on peripheral blood cells, thymus cells, spleen cells, and on foreign skin graft rejection assessed. When rabbit ATG was bound covalently to Tr, an alkylating agent, the conjugate (ATG-Tr) retained both complement-dependent antithymus cell acitivity and alkylating activity in vitro, but these activities were reduced. In vivo ATG decreased lymphocytes and increased neutrophils in the blood. ATG-Tr reduced circulating lymphocytes to lower levels and partially attenuated the rise in neutrophils. The in vivo effects of ATG, Tr, ATG-Tr, and ATG mixed with Tr (ATG + Tr) on thymus cells, spleen cells, T lymphocytes in the spleen, and rejection of a foreign skin graft were compared. Tr decreased all cell types, especially thymocytes, but did not delay graft rejection. ATG and ATG-Tr decreased thymocytes, eradicated T cells from the spleen, and delayed graft rejection 3-fold. ATG + Tr decreased thymocytes as Tr had done, eradicated T cells from the spleen, and delayed graft rejection 5-fold. It was concluded that ATG-Tr possessed antithymocyte antibody activity and Tr alkylating activity, but did not confer an immunological advantage over ATG alone, and that ATG and Tr mixed together unbound acted synergistically to delay graft rejection.