Effects of Chronic Static Stretching on Maximal Strength and Muscle Hypertrophy: A Systematic Review and Meta-Analysis with Meta-Regression

BACKGROUND

Increases in maximal strength and muscle volume represent central aims of training interventions. Recent research suggested that the chronic application of stretch may be effective in inducing hypertrophy. The present systematic review therefore aimed to syntheisize the evidence on changes of strength and muscle volume following chronic static stretching.

METHODS

Three data bases were sceened to conduct a systematic review with meta-analysis. Studies using randomized, controlled trials with longitudinal (≥ 2 weeks) design, investigating strength and muscle volume following static stretching in humans, were included. Study quality was rated by two examiners using the PEDro scale.

RESULTS

A total of 42 studies with 1318 cumulative participants were identified. Meta-analyses using robust variance estimation showed small stretch-mediated maximal strength increases (d = 0.30 p < 0.001) with stretching duration and intervention time as significant moderators. Including all studies, stretching induced small magnitude, but significant hypertrophy effects (d = 0.20). Longer stretching durations and intervention periods as well as higher training frequencies revealed small (d = 0.26-0.28), but significant effects (p < 0.001-0.005), while lower dosage did not reach the level of significance (p = 0.13-0.39).

CONCLUSIONS

While of minor effectiveness, chronic static stretching represents a possible alternative to resistance training when aiming to improve strength and increase muscle size. As a dose-response relationship may exist, higher stretch durations and frequencies as well as long program durations should be further elaborated.

Recombinant BoHV-5 glycoprotein (rgD5) elicits long-lasting protective immunity in cattle

BoHV-5 is a worldwide distributed pathogen usually associated with a lethal neurological disease in dairy and beef cattle resulting in important economic losses due to the cattle industry. Using recombinant gD5, we evaluated the long-duration humoral immunity of the recombinant vaccines in a cattle model. Here we report that two doses of intramuscular immunization, particularly with the rgD5ISA vaccine, induce long-lasting antibody responses. Recombinant gD5 antigen elicited tightly mRNA transcription of the Bcl6 and the chemokine receptor CXCR5 which mediate memory B cells and long-lived plasma cells in germinal centers. In addition, using an in-house indirect ELISA we observed higher and earlier responses of rgD5-specific IgG antibody and the upregulation of mRNA transcription of IL2, IL4, IL10, IL15, and IFN-γ in rgD5 vaccinated cattle, indicating a mixed immune response. We further show that rgD5 immunization protects against both BoHV -1 and -5. Our findings indicate that the rgD5-based vaccine represents an effective vaccine strategy to induce an efficient control of herpesviruses.

Lifelong versus not lifelong death wishes in older adults without severe illness: a cross-sectional survey

BACKGROUND

Some older adults with a persistent death wish without being severely ill report having had a death wish their whole lives (lifelong persistent death wish; L-PDW). Differentiating them from older adults without severe illness who developed a death wish later in life (persistent death wish, not lifelong; NL-PDW) can be relevant for the provision of adequate help and support. This study aims to gain insight into the characteristics, experiences, and needs of older adults with a L-PDW versus older adults with a NL-PDW and into the nature of their death wishes.

METHODS

In the Netherlands, in April 2019, a cross-sectional survey study was conducted among a large representative sample of 32,477 citizens aged 55 years and older. Respondents with a L-PDW (N = 50) were compared with respondents with a NL-PDW (N = 217) using descriptive statistics, Kruskal-Wallis tests, and Fisher's exact tests.

RESULTS

Respondents with a L-PDW were relatively younger and less often had (step)children. They less often looked back on a good and satisfying life with many good memories and more often reported trauma. Older adults with a NL-PDW more often reported loss and bereavement. Overall, the groups showed a lot of similarities. Both groups reported a death wish diverse in nature, numerous health problems, and a variety of needs for help and support.

CONCLUSIONS

Some of the differences we found between the groups might be particularly relevant for the provision of adequate help and support to older adults with a L-PDW (i.e., their past and trauma) and to older adults with a NL-PDW (i.e., their loss and bereavement). The heterogeneity of both groups and the diverse nature of their death wish indicate that careful assessment of the death wish, its background, and underlying needs is required to provide personalized help and support to older adults with a death wish.

Rational design, engineer, and characterization of a novel pegylated single isomer human arginase for arginine depriving anti-cancer treatment

AIMS

Arginine depleting enzymes are found effective to treat arginine-auxotrophic cancers and therapy-resistant malignancies, alone or in combination with cytotoxic agents or immune checkpoint inhibitors. We aim to select and validate a long-lasting, safe and effective PEGylated and cobalt-chelated arginase conjugated at the selective cysteine residue as a therapeutic agent against cancers.

MAIN METHODS

Exploring pharmacokinetic and pharmacodynamic properties of the three arginase conjugates with different PEG modality (20 kDa linear as A20L, 20 kDa branched as A20Y, and 40 kDa branched as A40Y) by cell-based and animal studies.

KEY FINDINGS

Arginase conjugates showed comparable systemic half-lives, about 20 h in rats and mice. The extended half-life of PEGylated arginase was concurrent with the integrity of conjugates of which PEG and protein moieties remain attached in bloodstream for 72 h after drug administration. Arginase modified with a linear 20 kDa PEG (A20L) was chosen as the lead candidate (PT01). In vitro assays confirmed the very potent cytotoxicity of PT01 against cancer cell lines of breast, prostate, and pancreas origin. In MIA PaCa-2 pancreatic and PC-3 prostate tumor xenograft models, weekly infusion of the PT01 at 5 and 10 mg/kg induced significant tumor growth inhibition of 44-67%. All mice experienced dose-dependent but rapidly reversible weight loss following each weekly dose, suggesting tolerable toxicity.

SIGNIFICANCE

These non-clinical data support PT01 as the lead candidate for clinical development that may benefit cancer patients by providing an alternative cytotoxic mechanism.

Potential use of 3-(trimethoxysilyl)propyldimethyl octadecyl ammonium chloride as an antimicrobial and antiviral agent for the disinfection of personal protective equipment

Currently, no vaccine or established therapeutic agents are available for coronavirus disease 2019. The sharp increase in demand for personal protective equipment (PPE) necessitates an improvement in the protective efficacy of PPE. We evaluated the potential antimicrobial and antiviral effects of a surface-coating disinfectant (3-(trimethoxysilyl)propyldimethyl octadecyl ammonium chloride, Si-QAC) when applied onto PPE. Si-QAC-pre-coated PPE was artificially contaminated with either influenza virus or Salmonella. The results showed significantly reduced influenza and Salmonella titers in Si-QAC-coated PPE; these antimicrobial effects lasted 7 days. This suggests that this surface-coating disinfectant effectively reduces pathogen contamination of PPE, enabling their safe and long-term use.

Protection of horse ears against Simulid parasitism: Efficacy of a mammal semiochemical solution over 10hours

Hematophagous insects can be vectors of pathogens and cause significant economic loss in zootechnical production. Among biting insects, many dipteran species feed on horse blood. The black fly (Diptera: Simuliidae) group, is responsible for several disorders in horses and inflicts painful bites that lead to undesirable behaviours in horses, particularly when bites occur in sensitive areas such as the inner ear. A field study was conducted in a French equestrian center during which a semiochemical was applied on horses' ears to assess repellent efficacy against simulid infestation. During the first phase of the study, efficacy was evaluated over a one hour period. Then, during the second phase of the study, persistency of the effect was tested at 8, 9 and 10h after application. The results of the study's first phase showed 90% efficacy over one hour, with 121.5 insects found in control ears and 12 insects in treated ears (p=0.001). In the second phase of the study, a total amount of 411 insects were observed on control ears whereas only 2 insects were observed on treated ears (p<0.0001); the treatment remained over 98% effective up to 10hours after application. When using a slow release excipient, this semiochemical may offer at least 10h of protection against simulids. This safe, efficient, and long lasting protection could help horses and their owners to manage simulid parasitism.

Effectiveness of 0.05% oxymetazoline (Vicks Sinex Micromist®) nasal spray in the treatment of objective nasal congestion demonstrated to 12 h post-administration by magnetic resonance imaging

INTRODUCTION

This study aimed to assess the qualitative and quantitative utility of MRI imaging to illustrate the magnitude and duration of the effect of a standard 100 μg dose of oxymetazoline in a commercially available formulation that also contains aromatic oils.

METHODS

This was a randomized, open label, single dose, parallel group study in 21 adult male and female subjects who reported moderate to severe nasal congestion due to acute upper respiratory tract infection or hay fever. MRI scans were acquired using a 3T Philips Achieva scanner with a 16 channel head receive coil. High resolution MRI scans of the nasal turbinates were obtained immediately prior to dosing (baseline) and at approximately 1, 8, 10, 11, and 12 h after dosing. The efficacy variables of primary interest were inferior turbinate total volume at 8 and 12 h post-dosing. The secondary efficacy variables analysed were inferior turbinate total volume at 1, 10, and 11 h post-dosing, middle turbinate total volume at 1, 8, 10, 11, and 12 h post-dosing.

RESULTS

Changes from baseline volumes measured for the inferior and middle turbinates of subjects receiving the oxymetazoline formulation showed significant (P < 0.05) decreases at all times up to and including 12 h post-administration. No significant decreases from baseline were detected in subjects receiving a sham 'spray' (untreated control - spray bottles with no spray solution). Statistical ANCOVA results of inferior and middle turbinate volume indicated significant differences (P < 0.05) at all measurement points up to and including 12 h post-administration between the oxymetazoline treatment group and the untreated control with the only exception the middle turbinate volume at 10 h (P = 0.0896). The significant changes were likely to be clinically relevant though this was not measured in the study. No AEs were reported during this study and no other safety evaluations were made.

CONCLUSIONS

This study showed that MRI assessment of nasal congestion in human volunteers is a robust, repeatable and viable measurement technique. The application of a 100 μg Vicks Sinex Micromist(®) nasal decongestant (0.05% oxymetazoline solution) delivered a highly significant reduction in inferior and middle turbinate volumes compared with the application of a control, measurable by the MRI method up to and including a 12 h post-dose scan.