Mitochondrial DNA replication in sea urchin oocytes

Mitochondrial DNA (mtDNA) replicative intermediates from Strongylocentrotus purpuratus oocytes were isolated by ethidium bromide-CsCl density gradient centrifugation and examined by electron microscopy after formamide spreading. In some experiments, the mtDNA was radioactively labeled by exposing isolated oocytes to [3H]thymidine. Oocyte mtDNA replication appears to follow the displacement loop model outlined in mouse L cells. There are differences in detail. The frequency of D-loop DNA is much lower in oocytes, suggesting that the relative holding time at the D-loop stage is shorter. Duplex synthesis on the displaced strand occurs early and with multiple initiations. The frequency of totally duplex replicative forms, or Cairns' forms, is the highest reported for mtDNA. The differences may be related to the fact that oocyte mtDNA replication occurs in the absence of cell division and need not be coordinated with a cell cycle. Molecules with expanded D loops banded in the intermediate region between the lower and upper bands in an ethidium bromide-CsCl gradient, supporting the notion that displacement replication proceeds on a closed circular template which is subject to nicking-closing cycles. In mature sea urchin eggs, replicative forms are absent and virtually all the mtDNA is stored as clean circular duplexes. Some novel structural variants of superhelical circular DNA (molecules with denaturation loops and double branch-migrated replicative forms) are reported

The association between embedded catheter implantation and hospitalization costs for peritoneal dialysis initiation: a retrospective cohort study

Background: Compared with the conventional peritoneal dialysis (PD) catheter insertion, embedding PD catheter implantation is one of the procedures for planned PD initiation. However, facilities where embedded PD catheter implantation is available are limited, and the impact of embedded PD catheter implantation on hospitalization cost and length of hospitalization is unknown. Methods: This retrospective single-center cohort study included 132 patients with PD initiation between 2005 and 2020. The patients were divided into two groups: 64 patients in the embedding group and 68 patients in the conventional insertion group. We created a multivariable generalized linear model (GLM) with the gamma family and log-link function to evaluate the association among catheter embedding, the duration and medical costs of hospitalization for PD initiation. We also evaluated the effect modification between age and catheter embedding. Results: Catheter embedding (β coefficient − 0.13 [95% confidence interval − 0.21, − 0.05]) and age (per 10 years 0.08 [0.03, 0.14]) were significantly associated with hospitalization costs. Catheter embedding (− 0.21 [− 0.32, − 0.10]) and age (0.11 [0.03, 0.19]) were also identified as factors significantly associated with length of hospitalization. The difference between the embedding group and the conventional insertion group in hospitalization costs for PD initiation (P for interaction = 0.060) and the length of hospitalization (P for interaction = 0.027) was larger in young-to-middle-aged patients than in elderly patients. Conclusions: Catheter embedding was associated with lower hospitalization cost and shorter length of hospitalization for PD initiation than conventional PD catheter insertion, especially in young-to-middle-aged patients.The version of record of this article, first published in Clinical and Experimental Nephrology, is available online at Publisher’s website: https://doi.org/10.1007/s10157-023-02416-

First-in-human phase 1 trial of hemoglobin vesicles as artificial red blood cells developed for use as a transfusion alternative

[Figure: see text

O laboratório como espaço da produção dos fatos científicos no pensamento de Latour e Woolgar

Neste artigo faremos uma apresentação crítica do “realismo ascendente” de Bruno Latour e Steve Woolgar, em Vida de Laboratório, obra em que investigam o funcionamento de um laboratório de neuroendocrinologia buscando compreender como os fatos científicos são socialmente construídos. Assumindo uma postura radical, descartam a ontologia realista mais comum, rompem com a epistemologia da filosofia da ciência tradicional, com a história e a sociologia da ciência e mesmo com a antropologia. Concluem que o laboratório – primeiro aquele específico, estudado, e depois em sentido geral – é um espaço de produção literária técnica onde os fatos científicos são construídos. A concepção de ciência dos autores levanta problemas filosóficos tradicionais, além de requerer uma formalização lógica

Effect of CYP3A5*3 genetic variant on the metabolism of direct-acting antivirals in vitro : a different effect on asunaprevir versus daclatasvir and beclabuvir

Direct-acting antivirals, asunaprevir (ASV), daclatasvir (DCV), and beclabuvir (BCV) are known to be mainly metabolized by CYP3A enzymes; however, the differences in the detailed metabolic activities of CYP3A4 and CYP3A5 on these drugs are not well clarified. The aim of the present study was to elucidate the relative contributions of CYP3A4 and CYP3A5 to the metabolism of ASV, DCV, and BCV, as well as the effect of CYP3A5*3 genetic variant in vitro. The amount of each drug and their major metabolites were determined using LC-MS/MS. Recombinant CYP3As and CYP3A5*3-genotyped human liver microsomes (CYP3A5 expressers or non-expressers) were used for the determination of their metabolic activities. The contribution of CYP3A5 to ASV metabolism was considerable compared to that of CYP3A4. Consistently, ASV metabolic activity in CYP3A5 expressers was higher than those in CYP3A5 non-expresser. Moreover, CYP3A5 expression level was significantly correlated with ASV metabolism. In contrast, these observations were not found in DCV and BCV metabolism. To our knowledge, this is the first study to directly demonstrate the effect of CYP3A5*3 genetic variants on the metabolism of ASV. The findings of the present study may provide basic information on ASV, DCV, and BCV metabolisms

Voxel-based structural magnetic resonance imaging (MRI) study of patients with early onset schizophrenia

<p>Abstract</p> <p>Background</p> <p>Investigation into the whole brain morphology of early onset schizophrenia (EOS) to date has been sparse. We studied the regional brain volumes in EOS patients, and the correlations between regional volume measures and symptom severity.</p> <p>Methods</p> <p>A total of 18 EOS patients (onset under 16 years) and 18 controls matched for age, gender, parental socioeconomic status, and height were examined. Voxel-based morphometric analysis using the Brain Analysis Morphological Mapping (BAMM) software package was employed to explore alterations of the regional grey (GM) and white matter (WM) volumes in EOS patients. Symptoms were assessed using the Positive and Negative Syndrome Scale (PANSS).</p> <p>Results</p> <p>EOS patients had significantly reduced GM volume in the left parahippocampal, inferior frontal, and superior temporal gyri, compared with the controls. They also had less WM volume in the left posterior limb of the internal capsule and the left inferior longitudinal fasciculus. The positive symptom score of PANSS (higher values corresponding to more severe symptoms) was negatively related to GM volume in the bilateral posterior cingulate gyrus. The negative symptom score was positively correlated with GM volume in the right thalamus. As for the association with WM volume, the positive symptom score of PANSS was positively related to cerebellar WM (vermis region), and negatively correlated with WM in the brain stem (pons) and in the bilateral cerebellum (hemisphere region).</p> <p>Conclusion</p> <p>Our findings of regional volume alterations of GM and WM in EOS patients coincide with those of previous studies of adult onset schizophrenia patients. However, in brain regions that had no overall structural differences between EOS patients and controls (that is, the bilateral posterior cingulate gyrus, the right thalamus, the cerebellum, and the pons), within-subject analysis of EOS patients alone revealed that there were significant associations of the volume in these areas and the symptom severity. These findings suggest that at an early stage of the illness, especially for those with onset before brain maturation, a wide range of disturbed neural circuits, including these brain regions that show no apparent morphological changes, may contribute to the formation of the symptomatology.</p

Effects of sodium-glucose co-transporter 2 inhibitors on ultrafiltration in patients with peritoneal dialysis: a protocol for a randomized, double-blind, placebo-controlled, crossover trial (EMPOWERED)

The version of record of this article, first published in Clinical and Experimental Nephrology, is available online at Publisher’s website: https://doi.org/10.1007/s10157-024-02467-w.Background: Volume overload is common and associated with high mortality in patients on peritoneal dialysis (PD). Traditional strategies including diuretics, water/salt restriction, and icodextrin-based solutions cannot always fully correct this condition, necessitating novel alternative strategies. Recent studies confirmed the expression of sodium–glucose cotransporter 2 (SGLT2) in the human peritoneum. Experimental data suggest that SGLT2 inhibitors decrease glucose absorption from the PD solution, thereby increasing the ultrafiltration volume. This trial aims to assess whether SGLT2 inhibitors increase the ultrafiltration volume in patients on PD. Methods: The EMPOWERED trial (trial registration: jRCTs051230081) is a multicenter, randomized, double-blind, placebo-controlled, crossover trial. Patients with clinically diagnosed chronic heart failure are eligible regardless of the presence of diabetes if they use at least 3 L/day glucose-based PD solutions. Participants will be randomly assigned (1:1) to receive empagliflozin 10 mg once daily and then placebo or vice versa. Each treatment period will last 8 weeks with a 4-week washout period. This study will recruit at least 36 randomized participants. The primary endpoint is the change in the daily ultrafiltration volume from baseline to week 8 in each intervention period. The key secondary endpoints include changes in the biomarkers of drained PD solutions, renal residual function, and anemia-related parameters. Conclusions: This trial aims to assess the benefit of SGLT2 inhibitors in fluid management with a novel mechanism of action in patients on PD. It will also provide insights into the effects of SGLT2 inhibitors on solute transport across the peritoneal membrane and residual renal function

Minor contribution of CYP3A5 to the metabolism of hepatitis C protease inhibitor paritaprevir in vitro

Paritaprevir (PTV) is a non-structural protein 3/4A protease inhibitor developed for the treatment of hepatitis C disease as a fixed dose combination of ombitasvir (OBV) and ritonavir (RTV) with or without dasabuvir. The aim of this study was to evaluate the effects of cytochrome P450 (CYP) 3A5 on in vitro PTV metabolism using human recombinant CYP3A4, CYP3A5 (rCYP3A4, rCYP3A5) and human liver microsomes (HLMs) genotyped as either CYP3A5*1/*1, CYP3A5*1/*3 or CYP3A5*3/*3. The intrinsic clearance (CLint, Vmax/Km) for the production of a metabolite from PTV in rCYP3A4 was 1.5 times higher than that in rCYP3A5. The PTV metabolism in CYP3A5*1/*1 and CYP3A5*1/*3 HLMs expressing CYP3A5 was comparable to that in CYP3A5*3/*3 HLMs, which lack CYP3A5. CYP3A4 expression level was significantly correlated with PTV disappearance rate and metabolite formation. In contrast, there was no such correlation found for CYP3A5 expression level. This study represents that the major CYP isoform involved in PTV metabolism is CYP3A4, with CYP3A5 having a minor role in PTV metabolism. The findings of the present study may provide foundational information on PTV metabolism, and may further support dosing practices in HCV-infected patients prescribed PTV-based therapy

The relationship between physical signs of aging and social functioning in persons with Down syndrome in Japan

Background: In Japan, there have been no substantial studies of social function and physical aging in adults with Down syndrome. The aim of the present study was to examine social functions (movement, conversation, and daily living skills) and physical signs of aging in adults with Down syndrome in Japan, and to analyze the relationship between changes in social function and age.Methods: A cross-sectional survey of persons with Down syndrome who were 15 years of age or older (15-65 years old) was conducted. The survey was conducted in patients associations, institutes, group homes, and workplaces from July to December 2009. Primary caregivers, such as family members and institute staff, were asked to complete a questionnaire on the subjects’ living situation, movement ability, conversational skills, daily living skills, and 10 characteristics of physical aging at the time of the survey.Results: The total number of subjects was 315. Subjects’ movement ability, conversational ability, and daily living skills declined as a function of age. Canities (40.6%) were the most prevalent physical sign of aging, followed by missing teeth, hump back, and skin wrinkling. Further, physical aging was related to a decline in social functions (p < 0.001).Conclusion: The present study showed that adults with Down syndrome exhibit signs of physical aging earlier than do the general population, and that physical aging is associated with social functioning. Thus, the appearance of physical aging might indicate a decline in social functioning