Potentially inappropriate prescriptions in geriatric patients hospitalized in the internal medicine department of a referral hospital in Mexico.

BACKGROUND: Potentially inappropriate prescription (PIP) constitutes a risk for the development of adverse effects of a drug that outweigh its benefits, which can be considered inappropriate medication use. OBJECTIVE: To describe the prevalence of PIP in geriatric patients hospitalized at the internal medicine department of a referral hospital in Mexico. MATERIAL AND METHODS: Cross-sectional, descriptive design, with simple allocation of medical records from patients older than 65 years hospitalized between January 2016 and August 2017. The STOPP/START criteria were applied to identify the number of PIPs, the number of prescribed medications, number and type of comorbidities, as well as days of hospital stay. RESULTS: A prevalence of PIP of 73.3% was identified, with main comorbidities being hypertension and type 2 diabetes mellitus. A total of 1,885 prescribed medications were quantified; mean hospital stay was 6.3 days. CONCLUSIONS: A high prevalence of PIP was identified in hospitalized geriatric patients, hence the importance of applying the STOPP/START criteria and of the role of the pharmacist for validating the prescription prior to drug administration.

ANTECEDENTES: Una prescripción potencialmente inapropiada (PPI) constituye un riesgo de presentar efectos adversos por un fármaco que superan los beneficios de este, pudiendo considerarse como uso inadecuado de medicamentos. OBJETIVO: Describir la prevalencia de prescripciones potencialmente inapropiadas en pacientes geriátricos hospitalizados en el servicio de medicina interna de un hospital de referencia en México. MATERIAL Y MÉTODOS: Diseño descriptivo transversal, con asignación simple de expedientes clínicos de pacientes hospitalizados mayores de 65 años, entre enero de 2016 y agosto de 2017. Se aplicaron los criterios STOPP y START para identificar el número de PPI, cantidad de medicamentos prescritos, presencia, cantidad y tipo de comorbilidades, así como días de estancia hospitalaria. RESULTADOS: Se encontró una prevalencia de 73.3 % de PPI y las principales comorbilidades fueron hipertensión arterial y diabetes mellitus tipo 2. Se cuantificaron 1885 medicamentos prescritos; la estancia hospitalaria media fue de 6.3 días. CONCLUSIONES: Se identificó alta prevalencia de PPI en los pacientes geriátricos hospitalizados, de ahí la importancia de aplicar los criterios STOPP y START y del papel del farmacéutico en la validación de la prescripción antes de la administración de medicamentos.

The Role for the DSB Response Pathway in Regulating Chromosome Translocations.

In response to DNA double strand breaks (DSB), mammalian cells activate the DNA Damage Response (DDR), a network of factors that coordinate their detection, signaling and repair. Central to this network is the ATM kinase and its substrates at chromatin surrounding DSBs H2AX, MDC1 and 53BP1. In humans, germline inactivation of ATM causes Ataxia Telangiectasia (A-T), an autosomal recessive syndrome of increased proneness to hematological malignancies driven by clonal chromosomal translocations. Studies of cancers arising in A-T patients and in genetically engineered mouse models (GEMM) deficient for ATM and its substrates have revealed complex, multilayered roles for ATM in translocation suppression and identified functional redundancies between ATM and its substrates in this context. "Programmed" DSBs at antigen receptor loci in developing lymphocytes employ ubiquitous DDR factors for signaling and repair and have been particularly useful for mechanistic studies because they are region-specific and can be monitored in vitro and in vivo. In this context, murine thymocytes deficient for ATM recapitulate the molecular events that lead to transformation in T cells from A-T patients and provide a widely used model to study the mechanisms that suppress RAG recombinase-dependent translocations. Similarly, analyses of the fate of Activation induced Cytidine Deaminase (AID)-dependent DSBs during mature B cell Class Switch Recombination (CSR) have defined the genetic requirements for end-joining and translocation suppression in this setting. Moreover, a unique role for 53BP1 in the promotion of synapsis of distant DSBs has emerged from these studies.

Lymphocyte-specific compensation for XLF/cernunnos end-joining functions in V(D)J recombination.

Mutations in XLF/Cernunnos (XLF) cause lymphocytopenia in humans, and various studies suggest an XLF role in classical nonhomologous end joining (C-NHEJ). We now find that XLF-deficient mouse embryonic fibroblasts are ionizing radiation (IR) sensitive and severely impaired for ability to support V(D)J recombination. Yet mature lymphocyte numbers in XLF-deficient mice are only modestly decreased. Moreover, XLF-deficient pro-B lines, while IR-sensitive, perform V(D)J recombination at nearly wild-type levels. Correspondingly, XLF/p53-double-deficient mice are not markedly prone to the pro-B lymphomas that occur in previously characterized C-NHEJ/p53-deficient mice; however, like other C-NHEJ/p53-deficient mice, they still develop medulloblastomas. Despite nearly normal V(D)J recombination in developing B cells, XLF-deficient mature B cells are moderately defective for immunoglobulin heavy-chain class switch recombination. Together, our results implicate XLF as a C-NHEJ factor but also indicate that developing mouse lymphocytes harbor cell-type-specific factors/pathways that compensate for the absence of XLF function during V(D)J recombination.

Pembrolizumab with or Without Lenvatinib as First-line Therapy for Patients with Advanced Urothelial Carcinoma (LEAP-011): A Phase 3, Randomized, Double-Blind Trial.

BACKGROUND: Pembrolizumab plus lenvatinib has shown antitumor activity and acceptable safety in patients with platinum-refractory urothelial carcinoma (UC). OBJECTIVE: To evaluate pembrolizumab plus either lenvatinib or placebo as first-line therapy for advanced UC in the phase 3 LEAP-011 study. DESIGN, SETTING, AND PARTICIPANTS: Patients with advanced UC who were ineligible for cisplatin-based therapy or any platinum-based chemotherapy were enrolled. INTERVENTION: Patients were randomly assigned (1:1) to pembrolizumab 200 mg intravenously every 3 wk plus either lenvatinib 20 mg or placebo orally once daily. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Dual primary endpoints were progression-free survival (PFS) and overall survival (OS). An external data monitoring committee (DMC) regularly reviewed safety and efficacy data every 3 mo. RESULTS AND LIMITATIONS: Between June 25, 2019 and July 21, 2021, 487 patients were allocated to receive lenvatinib plus pembrolizumab (n = 245) or placebo plus pembrolizumab (n = 242). The median time from randomization to the data cutoff date (July 26, 2021) was 12.8 mo (interquartile range, 6.9-19.3). The median PFS was 4.5 mo in the combination arm and 4.0 mo in the pembrolizumab arm (hazard ratio [HR] 0.90 [95% confidence interval {CI} 0.72-1.14]). The median OS was 11.8 mo for the combination arm and 12.9 mo for the pembrolizumab arm (HR 1.14 [95% CI 0.87-1.48]). Grade 3-5 adverse events attributed to trial treatment occurred in 123 of 241 patients (51%) treated with lenvatinib plus pembrolizumab and in 66 of 242 patients (27%) treated with placebo plus pembrolizumab. This trial was terminated earlier than initially planned based on recommendation from the DMC. CONCLUSIONS: The benefit-to-risk ratio for first-line lenvatinib plus pembrolizumab was not considered favorable versus pembrolizumab plus placebo as first-line therapy in patients with advanced UC. PATIENT SUMMARY: Lenvatinib plus pembrolizumab was not more effective than pembrolizumab plus placebo in patients with advanced urothelial carcinoma.

IgH class switching and translocations use a robust non-classical end-joining pathway.

Immunoglobulin variable region exons are assembled in developing B cells by V(D)J recombination. Once mature, these cells undergo class-switch recombination (CSR) when activated by antigen. CSR changes the heavy chain constant region exons (Ch) expressed with a given variable region exon from Cmu to a downstream Ch (for example, Cgamma, Cepsilon or Calpha), thereby switching expression from IgM to IgG, IgE or IgA. Both V(D)J recombination and CSR involve the introduction of DNA double-strand breaks and their repair by means of end joining. For CSR, double-strand breaks are introduced into switch regions that flank Cmu and a downstream Ch, followed by fusion of the broken switch regions. In mammalian cells, the 'classical' non-homologous end joining (C-NHEJ) pathway repairs both general DNA double-strand breaks and programmed double-strand breaks generated by V(D)J recombination. C-NHEJ, as observed during V(D)J recombination, joins ends that lack homology to form 'direct' joins, and also joins ends with several base-pair homologies to form microhomology joins. CSR joins also display direct and microhomology joins, and CSR has been suggested to use C-NHEJ. Xrcc4 and DNA ligase IV (Lig4), which cooperatively catalyse the ligation step of C-NHEJ, are the most specific C-NHEJ factors; they are absolutely required for V(D)J recombination and have no known functions other than C-NHEJ. Here we assess whether C-NHEJ is also critical for CSR by assaying CSR in Xrcc4- or Lig4-deficient mouse B cells. C-NHEJ indeed catalyses CSR joins, because C-NHEJ-deficient B cells had decreased CSR and substantial levels of IgH locus (immunoglobulin heavy chain, encoded by Igh) chromosomal breaks. However, an alternative end-joining pathway, which is markedly biased towards microhomology joins, supports CSR at unexpectedly robust levels in C-NHEJ-deficient B cells. In the absence of C-NHEJ, this alternative end-joining pathway also frequently joins Igh locus breaks to other chromosomes to generate translocations.

Herpetic Anterior Uveitis Multicentre Longitudinal Study (The UVHER Project). Baseline Characteristics.

PURPOSE: The aim of the UVHER project is to evaluate the risk of development of optic nerve damage in patients with herpetic anterior uveitis (AU) prospectively followed over 2 years. Herein, we described the baseline characteristics. METHODS: This is a multicentre, prospective study. An aqueous humour tap was performed. Only patients with a positive PCR were included. Clinical characteristics, optical coherence tomography (OCT) parameters and visual field (VF) abnormalities were registered. RESULTS: 27 patients were included: 18 Herpes Simplex (HSV), one Varicella Zoster (VVZ), and 8Cytomegalovirus (CMV). Patients with HSV-AU had severe inflammation, iris atrophy and corneal involvement. In patients with CMV-AU, less inflammation and medium-to-large keratic precipitates were observed. OCT showed a thinner RNFL and GCL in CMV-AU patients in comparison to HSV patients. VF showed abnormalities in six cases. CONCLUSIONS: Patients in the UVHER cohort showed the typical clinical manifestations of herpetic AU. In CMV patients, optic nerve damage was observed at baseline, and in HSV patients, inflammation was more severe.

Ischemic Optic Neuropathy After Administration of a SARS-CoV-2 Vaccine: A Report of 2 Cases.

BACKGROUND Since the start of vaccination efforts against COVID-19, several presumed secondary ocular events have been described. We present 2 cases of non-arteritic anterior ischemic optic neuropathy (NA-AION) in patients whose symptoms appeared in the first 2 weeks after administration of the Pfizer-BioNTech COVID-19 mRNA BNT162b2/Cominarty vaccine. CASE REPORT The first patient was a 53-year-old man who presented visual field disturbance in the right eye 7 days after the first vaccine dose, and who consulted a physician 10 days after the second dose, when he experienced loss of vision in the left eye. After a full examination, bilateral anterior optic disc neuropathy was diagnosed. The second patient was a 65-year-old man who presented anterior optic disc neuropathy 12 days after his first vaccination. In both cases, arteritic origin was ruled out due to absence of systemic symptoms and because of normal levels of C-reactive protein and erythrocyte sedimentation rates. CONCLUSIONS Ischemic optic neuropathy is a rare adverse ocular secondary effect of COVID-19 vaccines. Further basic and clinical research is needed to elucidate the pathogenic mechanisms and better characterize the clinical picture of this entity.

Factors Possibly Associated with Mortality in Intubated COVID-19 Patients: A Retrospective Study.

In Mexico, there is a high mortality rate among patients intubated because of COVID-19. The objective of this study was to investigate the associations of age, comorbidities, and biochemical parameters with the in-hospital mortality of COVID-19 patients. A retrospective study of 79 intubated patients admitted to one hospital in Jalisco, Mexico, between July 2020 and January 2021 was performed. Demographic and clinical characteristics were collected. The mean age was 57.7 (±12.8) years, with 83.5% non-survivors and 16.5% survivors. Age, lactate dehydrogenase (LDH) and D-dimer levels were found to be significantly higher in the non-survivor group (p = 0.011, p = 0.026, p = 0.007, respectively). Patients ≥58 years had a high risk of mortality (OR = 7.017). Significant correlations were also found in some of the study variables: LDH levels and leukocyte count (r = 0.388, p = 0.034) and CRP levels and fibrinogen (r = 0.692, p ˂ 0.001) in the patients ˂58 years. Leukocyte count with LDH levels (r = 0.381, p = 0.024) were significant in the group ≥58 years. No significant difference was observed in the presence of diabetes mellitus (DM) and hypertension. In conclusion, according to logistic regression analysis, age over 58 years represents the main factor associated with mortality in these patients.

Antioxidant and Anti-Inflammatory Effects of Coenzyme Q10 Supplementation on Infectious Diseases.

With the appearance of new viruses and infectious diseases (ID) such as COVID-19 in 2019, as well as the lack of specific pharmacological tools for the management of patients with severe complications or comorbidities, it is important to search for adjuvant treatments that help improve the prognosis of infectious disease patients. It is also important that these treatments limit the oxidative and hyperinflammatory damage caused as a response to pathogenic agents, since, in some cases, an inflammatory syndrome may develop that worsens the patient's prognosis. The potential benefits of complementary nutrients and dietary interventions in the treatment of pathological processes in which oxidative stress and inflammation play a fundamental role have been widely evaluated. Coenzyme Q10 (CoQ10) is a supplement that has been shown to protect cells and be effective in cardiovascular diseases and obesity. Additionally, some studies have proposed it as a possible adjuvant treatment in viral infections. Preclinical and clinical studies have shown that CoQ10 has anti-inflammatory and antioxidant effects, and effects on mitochondrial dysfunction, which have been linked to the inflammatory response.

Impact of Pharmaceutical Education on Medication Adherence and Its Clinical Efficacy in Patients with Type 2 Diabetes and Systemic Arterial Hypertension.

Purpose: To evaluate the impact of pharmaceutical education on medication adherence in patients with Type 2 Diabetes and Systemic Arterial Hypertension. Patients and Methods: This randomized clinical trial enrolled patients with a diagnosis of Type 2 Diabetes Mellitus and Systemic Arterial Hypertension treated in an internal medicine outpatient clinic of a teaching hospital. One hundred and three patients were randomly assigned to the study groups; 51 to the control group and 52 to the intervention group with a 6 months follow-up. Medication adherence was assessed using the Morisky 8-item medication adherence scale. To improve patient adherence to treatment, a wallet card was provided with an up-to-date list of prescribed medications along with recommendations for follow-up care. Results: One hundred and seventy-nine patients were screened for eligibility, of which 103 (57.5%) participated in the study. The intervention group showed a statistically significant decrease in capillary glucose levels, glycated hemoglobin, systolic and diastolic blood pressure, total cholesterol and triglycerides compared to the control group. The frequencies on medication adherence levels at 3 and 6 months in the control group remained similar to baseline, while in the intervention group the frequency of high adherence increased significantly at 6 months (8.7% to 43.5%). Conclusion: A high percentage of patients are not achieving optimal control of their diabetes. Medication adherence rates were between 45-50% in patients at the baseline of the study, but after receiving education and support from a pharmacist, the intervened group showed a significant increase in their adherence.

Direct synthesis of NNN-donor enantiopure scorpionate ligands by an efficient diastereoselective nucleophilic addition to imines.

New enantiopure imines (1-9) with a chiral substrate to control the stereochemistry of a newly created stereogenic center have been synthesized by reaction of the commercially available (1R)-(-)-myrtenal and different primary amines. The diastereomerically enriched lithium-scorpionate compounds [Li(κ(3)-mobpza)(THF)] (10) (mobpza = N-p-methylphenyl-(1R and 1S)-1-[(1R)-6,6-dimethylbicyclo[3.1.1]-2-hepten-2-yl]-2,2-bis(3,5-dimethylpyrazol-1-yl)ethylamide), [Li(κ(3)-mobpza)(THF)] (11) (mobpza = N-p-methoxyphenyl-(1R and 1S)-1-[(1R)-6,6-dimethylbicyclo[3.1.1]-2-hepten-2-yl]-2,2-bis(3,5-dimethylpyrazol-1-yl)ethylamide), [Li(κ(3)-fbpza)(THF)] (12) (fbpza = N-p-fluorophenyl-(1R and 1S)-1-[(1R)-6,6-dimethylbicyclo[3.1.1]-2-hepten-2-yl]-2,2-bis(3,5-dimethylpyrazol-1-yl)ethylamide), and [Li(κ(3)-clbpza)(THF)] (13) (clbpza = N-p-chlorophenyl-(1R and 1S)-1-[(1R)-6,6-dimethylbicyclo[3.1.1]-2-hepten-2-yl]-2,2-bis(3,5-dimethylpyrazol-1-yl)ethylamide) were obtained by a diastereoselective 1,2-addition of an organolithium reagent to imines in good yield and with good diastereomeric excess (ca. 80%). The complexes [LiCl(κ(2)-R,R-fbpzaH)(THF)] (14) and [LiCl(κ(2)-R,R-clbpzaH)(THF)] (15) were obtained in enantiomerically pure form by the treatment of THF solutions of 12 or 13 with NH(4)Cl. The enantiomerically pure amines (R,R-mbpzaH) (16), (R,R-mobpzaH) (17), (R,R-fbpzaH) (18), and (R,R-clbpzaH) (19) were obtained by hydrolysis of the lithium-scorpionate compounds 10-13 with H(2)O. The lithium compound 12 was reacted with [TiCl(4)(THF)(2)] or [ZrCl(4)] to give the enantiopure complexes [MCl(3)(κ(3)-R,R-fbpza)] [M = Ti (20), Zr (21)]. The amine compound 18 reacted with [MX(4)] (M = Ti, X = O(i)Pr, OEt; M = Zr; X = NMe(2)) to give the complexes [MX(3)(κ(3)-R,R-fbpza)] (22-24). The reaction of Me(3)SiCl with [Zr(NMe(2))(3)(κ(3)-R,R-fbpza)] (24) in different molar ratios led to the halide-amide-containing complexes [ZrCl(NMe(2))(2)(κ(3)-R,R-fbpza)] (25) and [ZrCl(2)(NMe(2))(κ(3)-R,R-fbpza)] (26) and the halide complex 21. The isolation of only one of the three possible diastereoisomers of complexes 25 and 26 revealed that chiral induction from the ligand to the zirconium center took place. The structures of these compounds were elucidated by (1)H and (13)C{(1)H} NMR spectroscopy, and the X-ray crystal structures of 5, 12, 14, 15, and 24 were also established.

Multisystem Inflammatory Syndrome in Children (MIS-C) Following SARS-CoV-2 Infection: Role of Oxidative Stress.

With the appearance of the SARS-CoV-2 virus in December 2019, all countries in the world have implemented different strategies to prevent its spread and to intensively search for effective treatments. Initially, severe cases of the disease were considered in adult patients; however, cases of older school-age children and adolescents who presented fever, hypotension, severe abdominal pain and cardiac dysfunction, positive for SARS-CoV-2 infection, have been reported, with increased pro-inflammatory cytokines and tissue damage, condition denominated multisystemic inflammatory syndrome (MIS-C); The emerging data from patients with MIS-C have suggested unique characteristics in the immunological response and also clinical similarities with other inflammatory syndromes, which can support as a reference in the search for molecular mechanisms involved in MIS-C. We here in propose that oxidative stress (OE) may play a very important role in the pathophysiology of MIS-C, such as occurs in Kawasaki disease (KD), severe COVID-19 in adults and other processes with characteristics of vascular damage similar to MIS- C, for which we review the available information that can be correlated with possible redox mechanisms.

Mammalian SIRT1 limits replicative life span in response to chronic genotoxic stress.

The Saccharomyces cerevisiae chromatin silencing factor Sir2 suppresses genomic instability and extends replicative life span. In contrast, we find that mouse embryonic fibroblasts (MEFs) deficient for SIRT1, a mammalian Sir2 homolog, have dramatically increased resistance to replicative senescence. Extended replicative life span of SIRT1-deficient MEFs correlates with enhanced proliferative capacity under conditions of chronic, sublethal oxidative stress. In this context, SIRT1-deficient cells fail to normally upregulate either the p19(ARF) senescence regulator or its downstream target p53. However, upon acute DNA damage or oncogene expression, SIRT1-deficient cells show normal p19(ARF) induction and cell cycle arrest. Together, our findings demonstrate an unexpected SIRT1 function in promoting replicative senescence in response to chronic cellular stress and implicate p19(ARF) as a downstream effector in this pathway.

Human Forebrain Organoids from Induced Pluripotent Stem Cells: A Novel Approach to Model Repair of Ionizing Radiation-Induced DNA Damage in Human Neurons.

Human induced pluripotent stem cells (iPSCs) can generate virtually any cell type and therefore are applied to studies of organ development, disease modeling, drug screening and cell replacement therapy. Under proper culture conditions in vitro induced pluripotent stem cells (iPSCs) can be differentiated to form organ-like tissues, also known as "organoids", which resemble organs more closely than cells, in vivo. We hypothesized that human brain organoids can be used as an experimental model to study mechanisms underlying DNA repair in human neurons and their progenitors after radiation-induced DNA double-strand breaks (DSBs), the most severe form of DNA damage. To this end, we customized a protocol for brain organoid generation that is time efficient. These organoids recapitulate key features of human cortical neuron development, including a subventricular zone containing neural progenitors that mature to postmitotic cortical neurons. Using immunofluorescence to measure DNA DSB markers, such as γ-H2AX and 53BP1, we quantified the kinetics of DSB repair in neural progenitors within the subventricular zone for up to 24 h after a single 2 Gy dose of ionizing radiation. Our data on DNA repair in progenitor versus mature neurons indicate a similar timeline: both repair DNA DSBs which is mostly resolved by 18 h postirradiation. However, repair kinetics are more acute in progenitors than mature neurons in the mature organoid. Overall, this study supports the use of 3D organoid culture technology as a novel platform to study DNA damage responses in developing or mature neurons, which has been previously difficult to study.

Evolution of the immunoglobulin heavy chain class switch recombination mechanism.

To mount an optimum immune response, mature B lymphocytes can change the class of expressed antibody from IgM to IgG, IgA, or IgE through a recombination/deletion process termed immunoglobulin heavy chain (IgH) class switch recombination (CSR). CSR requires the activation-induced cytidine deaminase (AID), which has been shown to employ single-stranded DNA as a substrate in vitro. IgH CSR occurs within and requires large, repetitive sequences, termed S regions, which are parts of germ line transcription units (termed "C(H) genes") that are composed of promoters, S regions, and individual IgH constant region exons. CSR requires and is directed by germ line transcription of participating C(H) genes prior to CSR. AID deamination of cytidines in S regions appears to lead to S region double-stranded breaks (DSBs) required to initiate CSR. Joining of two broken S regions to complete CSR exploits the activities of general DNA DSB repair mechanisms. In this chapter, we discuss our current knowledge of the function of S regions, germ line transcription, AID, and DNA repair in CSR. We present a model for CSR in which transcription through S regions provides DNA substrates on which AID can generate DSB-inducing lesions. We also discuss how phosphorylation of AID may mediate interactions with cofactors that facilitate access to transcribed S regions during CSR and transcribed variable regions during the related process of somatic hypermutation (SHM). Finally, in the context of this CSR model, we further discuss current findings that suggest synapsis and joining of S region DSBs during CSR have evolved to exploit general mechanisms that function to join widely separated chromosomal DSBs.

On the search for NNO-donor enantiopure scorpionate ligands and their coordination to group 4 metals.

The preparation of new chiral bis(pyrazol-1-yl)methane-based NNO-donor scorpionate ligands in the form of the lithium derivatives [Li(bpzb)(THF)] [1; bpzb = 1,1-bis(3,5-dimethylpyrazol-1-yl)-3,3-dimethyl-2-butoxide] and [Li(bpzte)(THF)] [2; bpzte = 2,2-bis(3,5-dimethylpyrazol-1-yl)-1-p-tolylethoxide] or the alcohol ligands (bpzbH) (3) and (bpzteH) (4) has been carried out by 1,2-addition reactions with trimethylacetaldehyde or p-tolualdehyde. The separation of a racemic mixture of the alcohol ligand 3 has been achieved and gave an enantiopure NNO alcohol-scorpionate ligand in three synthetic steps: (i) 1,2-addition of the appropriate lithium derivative to trimethylacetaldehyde, (ii) esterification and separation of diastereoisomers 5, (iii) saponification. Subsequently, the enantiopure scorpionate ligand (R,R)-bpzmmH {6; R,R-bpzmmH = (1R)-1-[(1R)-6,6-dimethylbicyclo[3.1.1]2-hepten-2-yl]-2,2-bis(3,5-dimethylpyrazol-1-yl)ethanol} was obtained with an excellent diastereomeric excess (>99% de) in a one-pot process utilizing the aldehyde (1R)-(-)-myrtenal as a chiral substrate to control the stereochemistry of the newly created asymmetric center. These new chiral heteroscorpionate ligands reacted with [MX(4)] (M = Ti, Zr; X = NMe(2), O(i)Pr, OEt, O(t)Bu) in a 1:1 molar ratio in toluene to give, after the appropriate workup, the complexes [MX(3)(kappa(3)-NNO)] (7-18). The reaction of Me(3)SiCl with [Ti(NMe(2))(3)(bpzb)] (7) or [Ti(NMe(2))(3)(R,R-bpzmm)] (11) in different molar ratios gave the halide-amide-containing complexes [TiCl(NMe(2))(2)(kappa(3)-NNO)] (19 and 20) and [TiCl(2)(NMe(2))(kappa(3)-NNO)] (21 and 22) and the halide complex [TiCl(3)(kappa(3)-NNO)] (23 and 24). The latter complexes can also be obtained by reaction of the lithium compound 1 with TiCl(4)(THF)(2) and deprotonation of the alcohol group of 6 with NaH, followed by reaction with TiCl(4)(THF)(2) in a 1:1 molar ratio, respectively. Isolation of only one of the three possible diastereoisomers of the complexes 19 and 22 revealed that chiral induction from the ligand to the titanium center took place. The structures of these complexes were elucidated by (1)H and (13)C{(1)H} NMR spectroscopy, and the X-ray crystal structures of 3-7, 12, and 24 were also established. Finally, we evaluated the influence that the chiral center of the new heteroscorpionate complexes has on the enantioselectivity of the asymmetric epoxidation of allylic alcohols.

B-cell receptor cross-linking delays activation-induced cytidine deaminase induction and inhibits class-switch recombination to IgE.

BACKGROUND: During differentiation, B cells receive signals by antigen through the B-cell receptor (BCR) and signals that induce isotype switching. OBJECTIVE: We sought to investigate the effects of BCR ligation on isotype switching. METHODS: Naive B cells from BALB/c mice were stimulated with LPS plus IL-4 alone or plus anti-IgM (0.1-10 mug/mL). IgE and IgG1 levels in supernatants were measured by means of ELISA on day 6. Cmu or Cvarepsilon germline transcripts, activation-induced cytidine deaminase (AID), and Imu-Cvarepsilon postswitch transcripts were measured by means of RT-PCR. Deletional switch recombination was assessed by means of digestion circularization PCR of Smu-Svarepsilon products. RESULTS: BCR cross-linking inhibited IgE and IgG1 switching in a dose-dependent fashion. This was not due to inhibition of proliferation, increased apoptosis, or cell death. BCR cross-linking had no effect on Cmu or Cvarepsilon germline transcripts but suppressed the generation of Smu-Svarepsilon switch products and Imu-Cvarepsilon postswitch transcripts and caused a delay in the expression of AID mRNA, with decreased expression on days 2 and 3 after stimulation. Concomitantly, the number of DNA repair foci at the IgH locus on day 3 was significantly decreased. AID expression and activity became normal on day 4, but isotype switching remained profoundly diminished 8 days after stimulation. CONCLUSION: BCR cross-linking delays AID expression. This might interfere with class-switch recombination by disrupting the temporal coordination of signals that lead to class-switch recombination.

Loss of ARID1A in Tumor Cells Renders Selective Vulnerability to Combined Ionizing Radiation and PARP Inhibitor Therapy.

PURPOSE: Somatic inactivating mutations in ARID1A, a component of the SWI/SNF chromatin remodeling complex, are detected in various types of human malignancies. Loss of ARID1A compromises DNA damage repair. The induced DNA damage burden may increase reliance on PARP-dependent DNA repair of cancer cells to maintain genome integrity and render susceptibility to PARP inhibitor therapy.Experimental Design: Isogenic ARID1A-/- and wild-type cell lines were used for assessing DNA damage response, DNA compactness, and profiling global serine/threonine phosphoproteomic in vivo. A panel of inhibitors targeting DNA repair pathways was screened for a synergistic antitumor effect with irradiation in ARID1A-/- tumors. RESULTS: ARID1A-deficient endometrial cells exhibit sustained levels in DNA damage response, a result further supported by in vivo phosphoproteomic analysis. Our results show that ARID1A is essential for establishing an open chromatin state upon DNA damage, a process required for recruitment of 53BP1 and RIF1, key mediators of non-homologous end-joining (NHEJ) machinery, to DNA lesions. The inability of ARID1A-/- cells to mount NHEJ repair results in a partial cytotoxic response to radiation. Small-molecule compound screens revealed that PARP inhibitors act synergistically with radiation to potentiate cytotoxicity in ARID1A-/- cells. Combination treatment with low-dose radiation and olaparib greatly improved antitumor efficacy, resulting in long-term remission in mice bearing ARID1A-deficient tumors. CONCLUSIONS: ARID1A-deficient cells acquire high sensitivity to PARP inhibition after exposure to exogenously induced DNA breaks such as ionizing radiation. Our findings suggest a novel biologically informed strategy for treating ARID1A-deficient malignancies.

PARP1 depletion induces RIG-I-dependent signaling in human cancer cells.

DNA Damage Response (DDR) and DNA repair pathways are emerging as potent, ubiquitous suppressors of innate immune signaling in human cells. Here, we show that human cells surviving depletion of the Single Strand Break (SSB) repair protein PARP1 undergo p21-dependent senescence or cell cycle checkpoint activation in the context of activation of innate immune signaling, or viral mimicry. Specifically, we observe induction of a large number of interferon-stimulated genes (ISGs) and multiple pattern recognition receptors (PRRs; including RIG-I, MDA-5, MAVS, TLR3 and STING) and increased nuclear IRF3 staining. Mechanistically, depletion of the double-stranded RNA (dsRNA) helicase RIG-I or its downstream effector MAVS specifically rescues ISG induction in PARP1-depleted cells, suggesting that the RIG-I/MAVS pathway is required for sustained ISG expression in this context. Experiments with conditioned media or a neutralizing antibody to the α/ß-IFN receptor revealed that persistent ISG expression additionally requires an autocrine/paracrine loop. Finally, loss of PARP1 and radiation-induced DNA damage strongly synergize in the induction of p21 and ISGs. Overall, these findings increase our understanding of how PARP1 may suppress deleterious phenotypes associated to aging, inflammation and cancer in humans.

Oxidative Stress, Apoptosis, and Mitochondrial Function in Diabetic Nephropathy.

Diabetic nephropathy (DN) is the second most frequent and prevalent complication of diabetes mellitus (DM). The increase in the production of oxidative stress (OS) is induced by the persistent hyperglycemic state capable of producing oxidative damage to the macromolecules (lipids, carbohydrates, proteins, and nucleic acids). OS favors the production of oxidative damage to the histones of the double-chain DNA and affects expression of the DNA repairer enzyme which leads to cell death from apoptosis. The chronic hyperglycemic state unchains an increase in advanced glycation end-products (AGE) that interact through the cellular receptors to favor activation of the transcription factor NF-κB and the protein kinase C (PKC) system, leading to the appearance of inflammation, growth, and augmentation of synthesis of the extracellular matrix (ECM) in DN. The reactive oxygen species (ROS) play an important role in the pathogenesis of diabetic complications because the production of ROS increases during the persistent hyperglycemia. The primary source of the excessive production of ROS is the mitochondria with the capacity to exceed production of endogenous antioxidants. Due to the fact that the mechanisms involved in the development of DN have not been fully clarified, there are different approaches to specific therapeutic targets or adjuvant management alternatives in the control of glycemia in DN.