Assessing mitochondria-targeted acyl hydroquinones on the mitochondrial platelet function and cytotoxic activity: Role of the linker length

INTRODUCTION

The use of triphenylphosphonium cation (TPP+) linked to phenolic compounds by alkyl chains has a significant relevance as a mitochondrial delivery strategy in biomedicine because it affects mitochondrial bioenergetics in models of noncommunicable diseases such as cancer and cardiovascular-related conditions. Studies indicate that a long alkyl chain (10-12 carbon) increases the mitochondrial accumulation of TPP+-linked drugs. In contrast, other studies show that these compounds are consistently toxic to micromolar concentrations (as observed in platelets). In the present study, we evaluated the in vitro effect of three series of triphenylphosphonium-linked acyl hydroquinones derivates on the metabolism and function of human platelets using 3-9 carbons for the alkyl linker. Those were assessed to determine the role of the length of the alkyl chain linker on platelet toxicity.

METHODS

Human platelets were exposed in vitro to different concentrations (2-40 μM) of every compound; cellular viability, phosphatidylserine exposition, mitochondrial membrane potential (ΔΨm), intracellular calcium release, and intracellular ROS generation were assessed by flow cytometry. An in silico energetic profile was generated with Umbrella sampling molecular dynamics (MD).

RESULTS AND CONCLUSIONS

There was an increase in cytotoxic activity directly related to the length of the acyl chain and lipophilicity, as seen by three techniques, and this was consistent with a decrease in ΔΨm. The in silico energetic profiles point out that the permeability of the mitochondrial membrane may be involved in the cytotoxicity of phosphonium salts. This information may be relevant for the design of new TPP+ -based drugs with a safe cardiovascular profile.

The Use of Triphenyl Phosphonium Cation Enhances the Mitochondrial Antiplatelet Effect of the Compound Magnolol

Although platelets are anucleated cells, they have fully functional mitochondria, and currently, it is known that several processes that occur in the platelet require the action of mitochondria. There are plenty of mitochondrial-targeted compounds described in the literature related to cancer, however, only a small number of studies have approached their interaction with platelet mitochondria and/or their effects on platelet activity. Recent studies have shown that magnolia extract and mitochondria-targeted magnolol can inhibit mitochondrial respiration and cell proliferation in melanoma and oral cancer cells, respectively, and they can also induce ROS and mitophagy. In this study, the effect of triphenylphosphonium cation, linked by alkyl chains of different lengths, to the organic compound magnolol on human-washed platelets was evaluated. We demonstrated that the addition of triphenylphosphonium by a four-carbon linker to magnolol (MGN4) considerably enhanced the Magnolol antiplatelet effect by a 3-fold decrease in the IC50. Additionally, platelets exposed to MGN4 5 µM showed several differences from the control including increased basal respiration, collagen-induced respiration, ATP-independent respiration, and reduced ATP-dependent respiration and non-mitochondrial respiration.

[Epidemiology of neuromyelitis optica spectrum. New and old challenges]

INTRODUCTION

This epidemiological review on neuromyelitis optica spectrum disorder (NMOSD) focuses on describing the methodologies employed in studies conducted under the 2015 NMOSD criteria and the studies conducted in Spain and Latin America, as well as examining factors related to the prognosis of the disease.

DEVELOPMENT

The methodology used in the studies varies essentially in the application of different diagnostic criteria, sources of records, antibody detection techniques and standardisation methods. However, in general terms, NMOSD is distributed worldwide with an incidence/prevalence that is higher in women than in men, and in Asian and African-American countries than in Western countries. The frequency increases in parallel to age, with a peak incidence/prevalence in the 40-59 age range. The Latin American population has particular epidemiological characteristics linked to its racial and genetic mix. Finally, epidemiological variables, such as belonging to the black race, being of older age at onset and being female, are associated with a worse functional prognosis.

CONCLUSIONS

Epidemiological data on NMOSD vary from one study to another, largely due to discrepancies in the methodological designs. Although Latin American studies are scarce, the findings described are associated with their ethnic mix. The homogenisation of criteria and the use of similar diagnostic techniques and standardisation methods must be implemented for the correct study of the epidemiology of NMOSD.

Risk factors of severe COVID-19 in people with multiple sclerosis : A systematic review and meta-analysis

Objectives

To gather, synthesize, and meta-analyze data regarding the risk factors associated with a severe course of COVID-19 among patients with multiple sclerosis (pwMS).

Methods

MEDLINE, Embase, Scopus, and WoS were searched in May 2021. Briefly, the eligibility criteria included: 1) studies assessing COVID-19 severity among adult pwMS; 2) definitive diagnoses or high clinical suspicion of COVID-19; 3) a categorization of COVID-19 severity into at least two categories; 4) quantitative effect size and precision measurements; and 5) English language; and 6) clear effect size/precision measures. internal validity of studies was assessed using the NIH Quality Assessment Tools. A list of possible risk factors was created based on the search results and was later used in extraction, synthesis, and meta-analysis of the data.

Results

Thirteen studies were included in the syntheses. Outcome measures were either extracted from the papers, obtained from the primary researchers or calculated manually. The meta-analyses showed a significantly (P < 0.05) increased odds of a severe COVID-19 in pwMS with all of the assessed risk factors, except smoking and most DMTs.

Conclusion

This study facilitates evidence-based risk/benefit assessments in practice. Older men with progressive MS on anti-CD20 therapies are more at risk of an unfortunate COVID-19 outcome.

Fishers' perception of the interaction between the South American sea lions and the Chinook salmon fishery in southern Chile

We studied how the South American sea lion (SASL, Otaria flavescens) interacts with the operation of an artisanal fishery of Chinook salmon, a non-native species in Chile, using a combination of biological and social approaches, including a valuation by fishers about this interaction. During austral summer of 2019, an observer onboard artisanal fishing boats characterized the attack behavior of SASLs to gillnet-captured Chinook salmon during 33 hauls and analyzed which factors may affect the intensity of attacks. To analyze the relationship between fishers and SASLs, a Likert scale about the perception and views about nature was applied. A total of 23 interviews—including 35 open and 16 closed questions—with fishers were conducted to describe how they perceived the interactions with SASLs. Interactions with SASLs were recorded in 35% of the fishing events and varied depending on both operational factors, such as the number of boats, as well as environmental factors, such as moon’s luminosity. Even though SASL interactions resulted in seven fish (~ 70 kg) damaged of a total catch of 2815 kg (2.5%) during the survey, boats with a damaged catch by SASL lost up to 11% of their revenue. This is consistent with 87% of the interviewed fishers who considered that the conflict with the SASL negatively impacts their activity and results in economic losses. A negative perception towards SASLs likely results from personal experience and revenue loss, even though impacts of SASL interactions at the scale of the entire fishery may be less important. While older fishers with less formal education have a productivist and instrumental focus, younger fishers with a more sustainable and conservationist view of fishing offer an opportunity to lead an improved local understanding of the relationship between salmon, SASLs, and humans.

Partial hardware removal in guided growth surgery: A convenient strategy?

BACKGROUND

Tension band plates (TPBs) are frequently used in guided growth (CG) surgeries. Recently, the concept of removing the metaphyseal screw only to stop the growth modulating effect rather than completely removing the implant, has gained popularity. Although this strategy would have certain potential advantages, the associated risks are unknown. The aim of this study is to report the experience of three institutions with this strategy.

METHODS

A database was compiled with the demographic information of patients treated by guided growth using TBPs between January 2014 and January 2019 at three institutions. The cases where only the metaphyseal screw was removed were identified. The records were reviewed to analyze the indications, demographic data, characteristics of the procedure, complications and need for additional procedures.

RESULTS

We reviewed 28 partial hardware removals, performed in 10 patients (all male). Initial surgery was indicated for angular deformity (N = 6), and leg-length discrepancy (N = 4). The average age at the time of surgery was 9.5 ± 2.9 years (range 4 to 13 years). Three procedures were performed on the distal femur, 3 on the proximal tibia, 2 on the distal tibia, and 20 combined. The average follow-up was 23.3 ± 11 months (range 12 to 52 months). We observed recurrence of deformities in 7 of 28 (22%) limbs that required re-insertion of the metaphyseal screw. Two patients presented complications from the procedure: soft tissue irritation (N = 1) and angular deformity (N = 1). Both patients required unplanned surgery.

DISCUSSION

Partial hardware removal in guided growth surgery could favor the presentation of complications. The benefits of this strategy must be considered against the possible undesired effects generated by its application.

STUDY DESIGN

Therapeutic study (Level IV).

Fate of petroleum hydrocarbons in bioturbated pristine sediments from Caleta Valdés (Patagonia Argentina): An ex situ bioassay

Petroleum can pollute pristine shorelines as a consequence of accidental spills or chronic leaks. In this study, the fate of petroleum hydrocarbons in soft pristine sediment of Caleta Valdés (Argentina) subject to ex situ simulated oil pollution was assessed. Sedimentary columns were exposed to medium and high concentrations of Escalante Crude Oil (ECO) and incubated in the laboratory during 30 days. Levels of aliphatic hydrocarbons at different depths of the sedimentary column were determined by gas chromatography. Oil penetration was limited to the first three centimetres in both treatments, and under this depth, hydrocarbons were clearly biogenic (terrestrial plants) as in the whole sedimentary column of the control assay. Bioturbation by macrobenthic infauna was strongly impacted by oil pollution which resulted in reduced sediment oxygenation and low burial of petroleum hydrocarbons. This may partly explain the limited hydrocarbon biodegradation observed, as indicated by the relatively high values of the ratios nC17/pristane, nC18/phytane, and total resolved aliphatic hydrocarbons/unresolved complex mixture. Correspondingly, at the end of the experiment the most probable number of hydrocarbon-degrading bacteria reached ~ 10³ MPN g^-1 dry weight. These values were lower than those found in chronically polluted coastal sediments, reflecting a low activity level of the oil-degrading community. The results highlight the low attenuation capacities of Caleta Valdés pristine sediments to recover its original characteristics in a short time period if an oil spill occurs. In this work, we present a novel and integrative tool to evaluate the fate of petroleum hydrocarbons and their potential damage on pristine sediments.

Bartonella vinsonii subsp. berkhoffii and B. henselae in dogs

This study aimed to molecularly survey Bartonella in dogs from Chile. Quantitative real-time PCR (qPCR) for Bartonella spp. based on nuoG gene was performed in 139 blood samples taken from dogs belonging to rural localities of the Valdivia Province, Los Ríos region, southern Chile. nuoG qPCR-positive samples were submitted to conventional PCR assays for ftsZ, gltA, rpoB and nuoG genes and sequencing for speciation and phylogenetic analysis. Based upon qPCR results, Bartonella spp. occurrence in dogs was 4.3% (6/139). Out of six nuoG qPCR-positive samples, six, three, two and none showed positive results in cPCR assays based on gltA, ftsZ, rpoB and nuoG genes, respectively. Consistent sequencing results were obtained only for the ftsZ gene from sample #1532 (GeneBank accession number: MG252491), and gltA gene from samples #1535 (MG252490) and #1532 (148 bp fragment that was not deposited in GenBank). Phylogenetic analysis of ftsZ and gltA genes allowed speciation of two nuoG-positive samples, one as Bartonella vinsonii subsp. berkhoffii and the other as B. henselae. Bartonella vinsonii subsp. berkhoffii and B. henselae are detected for the first time in dogs from Chile, highlighting the importance of the canine population as a source of zoonotic agents and potential infection risk to humans.

[Acute mountain sickness at 3500 and 4250 m. A study of symptom, incidence and severity]

BACKGROUND

Acute Mountain Sickness (AMS) refers to signs and symptoms associated with hypobaric hypoxia. Its reported incidence is highly variable.

AIM

To determine the incidence of AMS symptoms and severity at 3,500 and 4,250 m above sea level.

SUBJECTS AND METHODS

A population of 362 soldiers without former exposure to altitude was studied. AMS symptoms, were assessed by an extensively used standard questionnaire (Lake Louise), applied 36-72 hours after exposure to high altitude.

RESULTS

A group of 200 recruits ascended to Putre (3,500 m) and a second group (162) ascended to Alto Pacollo (4,250 m). The incidence of AMS was 28% and 60% respectively (p < 0.05). Headaches and sleeping difficulties were the most frequent symptoms at both altitudes. Furthermore, severe digestive problems and dizziness were described in a high proportion of individuals at both 3,500 and 4,250 m.

CONCLUSIONS

The prevalence of AMS in this study is similar to that reported elsewhere at equivalent altitudes.

[Activity of imipenem and meropenem against strains of Acinetobacter baumannii isolated from various Chilean hospitals]

The activity of two carbapenem compounds, imipenem and meropenem, against 447 strains of Acinetobacter baumannii isolated between 1990 and 1998 in different Chilean hospitals was determined. MIC ranges, MIC(50) and MIC(90), were determined by an agar dilution method. Similar antibacterial activities were observed for both antibacterials; however, a slight increase in the MIC(50) of imipenem and meropenem, and in the MIC(90) of meropenem was found among strains isolated from 1997-1998. Although A. baumannii remains susceptible to these antibiotics, the MIC(50) and MIC(90) have increased in recent years.

[Adherence of Acinetobacter baumannii to rat tracheal tissue]

BACKGROUND

Acinetobacter baumannii is an important nosocomial pathogen whose virulence factors have not been fully elucidated.

AIM

To study the adherence and hemagglutinating capacity of several biotypes of Acinetobacter baumannii.

MATERIAL AND METHODS

Thirty nine strains of Acinetobacter baumannii isolated from hospitalized patients were studied. The adherence of these strains to small pieces of rat tracheal tissue was studied. Additionally, their ability to hemagglutinate human erythrocytes and the effect of D-mannose and D-galactose on the adherence and hemagglutinating capacity was assessed. Transmission electron microscopy of strains was performed looking for the presence of fimbriae.

RESULTS

All strains exhibited adherence to tissues. All strains had also D-mannose and D-galactose resistant hemagglutinating ability. Fimbriae were found in Acinetobacter baumannii and E coil cells.

CONCLUSIONS

Adherence of Acinetobacter baumannii to rat tracheal tissue, apparently not related to the presence of fimbriae, may be a virulence mechanism of this bacterium.

[Microdoses of BCG vaccine for prophylaxis in bladder cancer stage T1]

A prophylaxis with a minidose of BCG Vaccine (1 mgr.) is performed in vesical instillation during one year, to 108 patients bearing bladder cancer in the stage T1. In the first month the instillations are once a week, each fifteen days the second and third month and then, once a month for one year. An 19.4% of recurrences is obtained with an general average observation time of 37.3 months as well as an important increase of muster populations of T lymphocytes and a positive test of dinitroclorobenzene. As complications we have obtained an inguinal BCG adenitis and in a few cases disury and frequency for two or three days. We conclude that the doses of the BCG vaccine used during the period of one year, is satisfactory in the reduction of recurrences and without important complications.

[Soft tissue sarcoma. Combined treatment of drug therapy, radiotherapy and conservative surgery]

The preliminary results of a prospective and cooperative protocol for the treatment of soft tissue sarcomas of trunk and extremities, stages IB-IIIB are presented. Thirty one patients (17 males, 22 with a tumor larger than 5 cm) aged 16 to 68 years, were treated with one dose of epirubicin 70 mg/m2 i.v. and radiotherapy (3000 rads in 10 fractions) Two or three weeks later an ample surgical complications occurred in 6 patients and were all of infectious origin. The median follow up period has been of 26 months. During this period 5 patients presented late surgical complications (edema in 4 and a pathological fracture in 1), 2 patients had a local tumor recurrence and distant metastases appeared in 7. Actuarial survival was 60% at 48 months. Ninety six percent of surviving patients conserved their extremity. It is concluded that with this treatment modality local recurrence is acceptable, morbidity is low and that the majority of patients do not require amputations or crippling resection.

[Continuous hemodialysis in the treatment of chronic renal insufficiency in emergencies]

Continuous hemodialysis is advantageous for the treatment of renal failure in critically ill patients. This study reports our experience in the treatment of emergencies during chronic renal failure with continuous hemodialysis using a Cuprofane membrane. Eighteen patients with acute decompensations of chronic renal failure were treated with continuous hemodialysis (14 arteriovenous and 4 veno-venous). Procedures lasted a mean of 44.2 h, blood urea nitrogen decreased from 150.3 +/- 49.8 to 60.6 +/- 30.7 mg/dl, metabolic acidosis was corrected raising serum bicarbonate from 10.1 +/- 44 to 17.8 +/- 3.3 mEq/L and hyperkalemia was corrected. Mean ultrafiltration was 239.6 +/- 124.6 ml/h which allowed to withdraw a mean 10.590 ml of ultrafiltrate. Two patients were complicated with femoral artery pseudoaneurysms and one patient with a catheter related sepsis. Global mortality was 16.7%, which compared favorably with the 32.1% predicted mortality according to the Simplified Acute Physiology Score. It is concluded that continuous hemodialysis, a readily available procedure, is suitable for the treatment of emergencies during chronic renal failure.

[Impetigo in children: etiology and response to treatment]

Seventy seven cases of impetigo were studied in children. Group A beta hemolyticus Streptococcus was the only bacterial agent isolated from 25 culture samples, Staphylococcus aureus from 6 and both agents from 39 cases. Cultures were negative in 7 children. The clinical response to treatment with penicillin G benzathine, crust removal and skin cleansing was satisfactory in 93.5% of the cases, nonresponders (6.5%) were satisfactory treated oral with cloxacillin.