Victory above all: the weight loss practices and perceptions of Chinese male kickboxers
Objectives Kickboxing is a dynamic combat sport (CS) in which two competitors engage in full-force strikes using their hands, elbows, knees, shins, and feet. To ensure athletes compete against opponents of similar body size and weight for fairness, kickboxing competition is classified according to weight classes. Previous studies revealed that CS athletes tend to intentionally lose weight to gain a competitive advantage over their opponents. However, little is known about weight loss (WL) practices in kickboxers and the perceptions of CS athletes about WL. The aim of this study is to investigate the WL practices and perceptions of Chinese male kickboxers. Methods A total of 152 Chinese male kickboxers completed the adapted Rapid WL Questionnaire. Participants were categorized by age group, weight category, competitive level, attitude toward impact of WL on health, and performance. Results Sixty-eight percent of kickboxers purposefully engaged in WL practices. The average habitual WL was 6.0% of body mass (BM), with the average highest WL being 8.8% of BM. Most participants reduced 41–60% of their total planned magnitude of WL between 60 days and 9 days before the weigh-in, 21–40% between 8 days and 2 days before the weigh-in, and 0–20% within 1 day before the weigh-in. Coaches (67%) were most reported as the primary guides for WL. The primary reason kickboxers engage in WL is competing against lighter opponents to increase the chances of winning (70%). Most participants believed that WL had no impact on health (42%), improved performance (57%), and did not lead to unfair competition (73%). Significant differences were observed in both the highest WL% (p = 0.005, p = 0.018), the habitual WL% (p = 0.005, p = 0.018), the age beginning WL (p = 0.005, p = 0.018), and the annual WL times (p = 0.005, p = 0.018) across age and competitive level, but not observed across weight category, and attitudes toward both the health and performance impacts of WL (all p > 0.05). No significant differences were found in habitual weight regain after weigh-in/habitual WL (%) after weigh-in across all groups (all p > 0.05). Conclusions The prevalence of WL among Chinese male kickboxers is relatively low when compared to other CS, but the magnitude is relatively higher compared with previous studies. Their WL practices are mainly guided by kickboxing coach, and the primary reasons of WL is to gain a competitive advantage and improve performance.
Meng et al. (2025) Victory above all: the weight loss practices and perceptions of Chinese male kickboxers. PeerJ 13:e19709 https://doi.org/10.7717/peerj.19709
Clinical significance and heterogeneity of circulating tumor cells and clusters in breast cancer subtypes
The marked heterogeneity of breast cancer results in substantial variations in clinical characteristics, metastatic patterns, and prognosis across molecular subtypes. However, circulating tumor cells (CTCs) and circulating tumor cell clusters (CTC clusters), pivotal mediators of metastasis, have not been comprehensively evaluated for their biological characteristics and clinical significance across molecular subtypes. This review synthesizes recent research advancements to comprehensively examine the distribution characteristics, biological functions, and prognostic associations of CTCs and CTC clusters in luminal A, luminal B, HER2-positive breast cancer, and triple-negative breast cancer (TNBC). It was observed that HER2-positive breast cancer is associated with elevated CTC counts, whereas TNBC, despite lower CTC counts, exhibits CTCs and CTC clusters with enhanced invasiveness and metastatic potential due to Notch1 signaling pathway activation, elevated PD-L1 expression, and desialylation modifications. In luminal subtypes, the scarcity of CTC clusters is linked to a reduced metastatic risk; however, luminal B exhibits a greater propensity for CTC cluster formation than luminal A, suggesting prognostic differences. Clinical data demonstrate that CTC cluster counts are significantly inversely correlated with overall survival (OS) and disease-free survival (DFS), and that dynamic monitoring of CTC clusters enables prediction of treatment resistance and recurrence risk. Furthermore, the molecular profiles of CTCs (e.g., HER2 status, ESR1 mutations) facilitate personalized guidance for targeted and endocrine therapies. However, current detection technologies exhibit limitations in capturing CTC clusters with high efficiency and sensitivity, necessitating further optimization through microfluidic sorting, single-cell omics, and artificial intelligence approaches. This review underscores the heterogeneity of CTCs and CTC clusters across breast cancer subtypes, alongside their potential for clinical translation, offering theoretical support for prognostic evaluation and individualized treatment strategies in precision medicine. This study may be of considerable value to researchers and clinicians in the field of cancer metastasis.
Hao et al. (2025) Clinical significance and heterogeneity of circulating tumor cells and clusters in breast cancer subtypes. PeerJ 13:e19703 https://doi.org/10.7717/peerj.19703
Effect of modulating the extracellular matrix cross linkage by genipin on tumor cell resistance and survival in thioacetamide-induced hepatocellular carcinoma in rats
Background Previous studies on patients and rats with hepatocellular carcinoma (HCC) have shown significant changes in the extracellular matrix (ECM). Versican, a component of the ECM, forms extensive multimolecular interactions with other ECM components, particularly hyaluronan, through specific domains in its core protein. However, disturbances in the hyaluronan-versican interaction may affect cancer development. We aimed to examine the effect of modulating matrix cross-linkage between hyaluronan and versican using genipin on tumor cell survival, resistance, and renewal. Methods Following the induction of HCC in rats using thioacetamide, an oral dose of 10 mg/kg of genipin was administered. Liver impairment was evaluated by measuring serum α-fetoprotein (AFP) levels and examining liver sections stained with hematoxylin/eosin and anti-versican and anti-fibronectin antibodies. Additionally, hepatic expression levels of mRNA and proteins, including epidermal growth factor (EGF), epidermal growth factor receptor (EGFR), fibronectin, glycogen synthase kinase-3 beta (GSK-3β), protein kinase B (PKB), and versican, were analyzed. Results Genipin enhances rats’ survival, leading to reduction in serum AFP levels and number of hepatic nodules. Micro-imaging examinations reveal that genipin reduces vacuolated cytoplasm, apoptotic nuclei, and necrotic nodules. Additionally, it significantly lowers EGF, EGFR, fibronectin, GSK-3β, PKB, and versican expression levels. Conclusion Genipin may be considered novel anticancer agent with hepatoprotective effects. This is achieved by reducing versican-free forms. Additionally, genipin decreases tumor cells’ resistance by lowering the expression of EGF, EGFR, PKB, and GSK-3β. Finally, it reduces tumor cell survival by decreasing the expression of fibronectin.
Hassan et al. (2025) Effect of modulating the extracellular matrix cross linkage by genipin on tumor cell resistance and survival in thioacetamide-induced hepatocellular carcinoma in rats. PeerJ 13:e19680 https://doi.org/10.7717/peerj.19680
The reading difficulties in Chinese for individuals with attention deficit hyperactivity disorder: the role of executive function deficits
Background Attention-deficit/hyperactivity disorder (ADHD) and reading disability (RD) are prevalent childhood conditions that together affect millions of children worldwide. In China, the prevalence of ADHD is approximately 6.4%, whereas the prevalence of RD ranges from 3.45% to 8%. Approximately 18–45% of children with ADHD also display comorbid RD, which further compromises their academic success and social functioning. Executive-function (EF) deficits are a core feature of ADHD and are known to affect reading in RD, yet their specific impact on Chinese reading remains under-explored. Objective This study investigated how EF deficits influence Chinese reading in children with ADHD, with the goal of informing diagnosis and intervention for ADHD-RD comorbidity. Methods This study recruited 160 Chinese-speaking children who met DSM-5 criteria for ADHD and allocated them to two groups—ADHD-only (n = 80) and ADHD + RD (n = 80). ADHD symptoms were rated with the Swanson, Nolan and Pelham Teacher and Parent Rating Scale (SNAP-IV), whereas Chinese reading was evaluated with the Dyslexia Checklist for Chinese Children (DCCC). Executive functions were measured with tasks tapping visuospatial working memory, verbal working memory, and response inhibition (Go/No-Go). Results Both groups showed no significant differences in ADHD symptom scores. Compared with the ADHD-only group, the ADHD + RD group obtained higher total and subscale DCCC scores and lower accuracies on EF tasks. Total DCCC scores correlated negatively with EF performance, especially on visuospatial working-memory and response-inhibition tasks. Conclusion This study suggests that individuals with ADHD comorbid with Chinese reading disabilities (RD) exhibit more pronounced deficits in executive function, particularly in verbal and visual-spatial working memory, and response inhibition tasks, compared to individuals with ADHD alone. These cognitive deficits are significantly negatively correlated with Chinese reading abilities, emphasizing the importance of not only focusing on traditional ADHD symptoms but also prioritizing training to enhance executive functions, especially visual-spatial working memory and response inhibition, when diagnosing and treating patients with ADHD comorbid with RD, in order to improve their reading abilities.
Wei et al. (2025) The reading difficulties in Chinese for individuals with attention deficit hyperactivity disorder: the role of executive function deficits. PeerJ 13:e19679 https://doi.org/10.7717/peerj.19679
Gender differences in peak medial joint contact forces during activities of daily living
Women are more likely to suffer from knee osteoarthritis as compared to men. For men and women, greater peak knee medial joint contact force is associated with greater rates of knee osteoarthritis. However, it is unclear if the increased rates of knee osteoarthritis in women is associated with greater medial joint contact force. We hypothesize that because women experience greater rates of knee osteoarthritis, they would experience greater peak medial joint contact force. Fifty-two healthy, young participants (26 women, 26 men) performed sit-to-stand, stand-to-sit, self-selected speed walking, self-selected speed running, and set speed running trials over force plates while motion capture data was recorded. Medial joint contact force, scaled by bodyweight, was calculated with a reduction modeling approach from inverse dynamics data and ultrasound measured distances. Differences in peak medial joint contact force between men and women were tested with one-tailed unpaired Student’s t-tests with a Bonferroni correction. No significant differences were seen between groups peak medial joint contact force in any of the tested movements. Medial joint contact force may not be able to explain the disparity in knee osteoarthritis rates between men and women.
Snyder et al. (2025) Gender differences in peak medial joint contact forces during activities of daily living. PeerJ 13:e19677 https://doi.org/10.7717/peerj.19677
Chronic sleep deprivation is associated with delayed puberty onset in rats, activation of proinflammatory cytokines and gut dysbiosis
Chronic sleep deprivation (CSD) in adolescents has become a trend with adverse health outcomes. Previous studies have demonstrated that sleep deprivation causes inflammation, alters puberty onset, and changes the gut microbiome composition; however, the relationship between these is still unknown. Therefore, we hypothesized that CSD delays the onset of puberty via elevating proinflammatory cytokines and alter ation of gut microbiome composition. Using the modified multiple platform method, we conducted a 4-week CSD experiment in juvenile rats and assessed pubertal markers, antioxidant activity, cytokine levels, and gut microbiome profiles. CSD significantly reduces body weight, delays onset of puberty, and elevated antioxidant enzyme activities in both sexes. In the sleep-deprivation female (SDF) rats, plasma levels of lipopolysaccharide–binding protein (LBP), interleukin-1β (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) were significantly elevated; mRNA levels of TNF-α and IL-1β were also significantly elevated in the colon and reproductive organs, respectively. In the sleep-deprivation male (SDM) rats, only plasma levels of IL-6 were elevated considerably; in addition, mRNA levels of IL-1β and TNF-α were also significantly elevated in the colon and reproductive organs, respectively. Gut microbiome analysis revealed that the predominant bacteria at the genus level were Muribaculaceae, Prevotellaceae UCG-001, and Ruminococcaceae UCG-005 in the SDF rats; Prevotellaceae NK3B31, Ruminococcaceae UCG-010, Eubacterium coprostanoligenes, and Shuttleworthia in the SDM rats. CSD rats with abundant genera were positively correlated with antioxidant enzyme activities and mRNA levels of proinflammatory cytokines. Overall, CSD is associated with delayed puberty onset, possibly via an increase in the expression levels of proinflammatory cytokines and altering the gut microbiome composition, indicating proinflammatory cytokines and gut microbiome play an important role in pubertal timing change. These findings may guide the future studies to intervene sleep deprivation-related delays in the onset of puberty.
Gunawan et al. (2025) Chronic sleep deprivation is associated with delayed puberty onset in rats, activation of proinflammatory cytokines and gut dysbiosis. PeerJ 13:e19668 https://doi.org/10.7717/peerj.19668
Enhancing physical activity in older type 2 diabetic adults through remote patient monitoring: a pre-post study in Taiwan
Background Type 2 diabetes (T2D) is a growing concern among older adults, increasing the risk of frailty, and functional decline. In Taiwan, the convergence of population aging and high diabetes prevalence calls for innovative care strategies. This study evaluated the effectiveness of incorporating wearable step-count devices into the diabetic pay-for-performance (P4P) program to enhance physical activity and explore associations with related health outcomes. Methods This prospective, single-arm interventional study was conducted from February to September 2023 at a medical center in central Taiwan. T2D participants in P4P who were able to use smart phone were enrolled. At baseline, comprehensive geriatric assessment was performed to measure participants’ physical, mental functions and nutritional status. Daily step data were collected via Garmin trackers and synced automatically. Participants received weekly remote feedback from diabetes educators to encourage adherence in 2 months. The Wilcoxon signed-rank test assessed changes in step counts over time, and Spearman’s rank correlation examined associations with baseline health indicators. An association of daily step counts with metabolic controls factors, biochemical data, disease severity, functional performance, frailty, nutritional and mood were analyzed. Results The study involved 66 participants, median age 72 years, with 24 males (36.4%) and 42 females (63.6%). Metabolic indicators showed fasting plasma glucose at 110.0 mg/dL (interquartile range, IQR: 97.0–137.5) and hemoglobin A1c at 6.1 (IQR: 5.7–7.2). Additionally, low-density lipoprotein was 86.5 mg/dL (IQR: 67.3–104.5), and triglycerides were 98.5 mg/dL (IQR: 76.8–139.8). Urine albumin-creatinine ratio was 15.3 (IQR: 7.6–84.9), and estimated glomerular filtration rate (eGFR) was 70.7 mL/min/1.73 m2 (IQR: 48.9–78.1). Functional capacity varied, with 47.0% having low muscle strength and 92.0% showing low physical performance. 15.2% showed symptoms of depression. Malnutrition and frailty were observed in 6.1% and 13.6%, respectively. Median daily steps significantly increased from 1,560.8 (IQR: 955.9–3,301.5) in week 1 to 2,652.9 (IQR: 1,271.8–4,139.3) in the final week (p < 0.001). Higher daily step counts were positively correlated with physical and nutritional status and negatively correlated with age, depressive symptoms, and frailty. Remote monitoring led to a significant and consistent increase in daily step counts across all tracking periods (p < 0.001). Conclusions The study found that digital mobile health monitoring improved daily step counts over time in older diabetic patients, and baseline physical functions, and nutritional status were related to the changes. Whether incorporating this wearable technology into diabetes education program improves long metabolic controls needs further researches.
Lin et al. (2025) Enhancing physical activity in older type 2 diabetic adults through remote patient monitoring: a pre-post study in Taiwan. PeerJ 13:e19659 https://doi.org/10.7717/peerj.19659
Associations between squalene epoxidase gene polymorphisms and obesity
Background Among the known control points of cholesterol synthesis, squalene epoxidase (SQLE) is considered a key factor influencing cholesterol metabolism. Methods A total of 1,045 consecutive participants were divided into an obese group and a control group. Blood biochemical markers were measured, and deoxyribonucleic acid (DNA) was extracted from all participants. Statistical analyses were conducted to assess the associations between SQLE gene single nucleotide polymorphisms (SNPs) and obesity. Results The C/C genotype of SQLE SNP1 (rs10104486) was significantly more associated with obesity compared to the A/A genotype. A significant difference in genotype distribution frequency for rs10104486 was observed between the obese and control groups. The recessive model (CC vs. AC + AA) also showed a statistically significant difference. For SQLE SNP2 (rs2288312), differences were found in genotype distribution frequency, allele frequency, and the recessive model (GG vs. AA + AG) between the two groups. Conclusions This study indicates a correlation between the SQLE gene polymorphisms rs10104486 and rs2288312 and obesity in a young population. Participants carrying the C allele of rs10104486 were more likely to develop obesity than those carrying the A allele, with the CC genotype identified as a predisposing factor.
Yu et al. (2025) Associations between squalene epoxidase gene polymorphisms and obesity. PeerJ 13:e19635 https://doi.org/10.7717/peerj.19635
Internal structure of the action and acceptance questionnaire II (AAQ-II): evidence for a three-factor and bifactor model in two samples of university students
Background Experiential avoidance (EA), defined as an inflexible behavioral pattern by which a person tries to avoid contact with private unpleasant situations, is considered a transdiagnostic variable associated with various psychopathological disorders. The Acceptance and Action Questionnaire II (AAQ-II) is a broadly used measure of EA. However, inconsistencies in the methods employed for examining its internal structure and the need for culturally validated measures in diverse populations highlight the need for further study. We conducted two studies in Spanish-speaking university students (nStudy1 = 829; nStudy2 = 830) to determine the validity and reliability of the AAQ-II. Methods In the first study, we examined the questionnaire through exploratory factor analysis (EFA). In the second study, we conducted confirmatory factor analysis (CFA) to examine how well these factor structures fit our data. Results We suggested a three-factor structure (namely: painful memories, emotional distress, and affective control), in contrast with the unidimensional model consistently reported in the literature. The three-factor model showed a better fit overall. Additionally, we tested a bifactor model to determine the feasibility of a general factor. Our results suggested that this general factor explained a high amount of the variance within the model when compared to the three independent factors. In terms of convergent validity, significant positive associations were found between EA and suicidal ideation, depressive and anxious symptoms, while negative associations were found with psychological well-being. The factor structures tested showed good internal consistency indices (ω = 0.853–0.918; α = 0.853–0.918). Discussion We discuss our results in terms of their methodological and practical implications for the use of the AAQ-II.
Núñez et al. (2025) Internal structure of the action and acceptance questionnaire II (AAQ-II): evidence for a three-factor and bifactor model in two samples of university students. PeerJ 13:e19620 https://doi.org/10.7717/peerj.19620
Molecular evolution of TRPC4 regulatory sequences supports a role in mammalian thermoregulatory adaptation
Background Proteins encoded by the canonical transient receptor potential (Trpc) gene family form transmembrane channels involved in diverse signal-transduction pathways. Trpc4 has been shown necessary for the induction of nonshivering thermogenesis (NST) in mice, a key component of which is thermogenic brown adipose tissue (BAT). In bats, Trpc4 exhibited diversifying selection within exons encoding regulatory binding sites of TRPC4. Methods To assess whether diversification of these regulatory sequences mirrors the diversification of mammalian thermoregulatory strategies, the ratio of nonsynonymous to synonymous substitutions (ω) was estimated for multiple tetrapod outgroups and eutherian orders. Four questions were addressed: (1) Did the ancestral eutherian Trpc4 diverge under positive selection from nonplacental mammals that lack BAT? (2) Did Trpc4 subsequently become more constrained in descendant eutherian clades? (3) In eutherian clades that subsequently lost BAT by inactivation of the thermogenin gene Ucp1, did Trpc4 become less constrained? (4) Does the evolutionary rate of Trpc4 differ between quantitatively more heterothermic mammal orders (bats and rodents) relative to quantitatively less heterothermic outgroups (carnivores, artiodactylids, and primates)? Results Coincident with the advent of BAT, Trpc4 evolutionary rate increased significantly in ancestral eutheria after their divergence from nonplacental mammals but a branch-site model did not support a rate class ω > 1 along that branch. In descendant eutherian mammals, Trpc4 became far more constrained, with an evolutionary rate less than half that of tetrapod clades lacking NST, a pattern was not seen in other Trp channel genes. Intensifying selection in descendent eutherian mammals was further supported with the RELAX program, which also indicated reduced constraint on Trpc4 in clades that have secondarily lost BAT. However, no consistent pattern was identified within mammalian orders with strong variation in heterothermy: evidence of increased evolutionary rate was again found in bats for Trpc4 as well as homologs it directly binds in heteromeric membrane channels (Trpc5 and Trpc1), yet all rodent Trpc genes had low evolutionary rates. Evolutionary rates of Trpc4 and Trpc1 in bats were consistent with relaxed constraint whereas bat Trpc5 experienced diversifying selection. Most variation among tetrapod TRPC4 sequences lies within an 85 amino-acid window that is functionally uncharacterized. Sequence alignments demonstrated that the TRPC4 β isoform, which lacks a portion of the C-terminal regulatory region, originated in basal eutherians but appears to be lost in many tip lineages. Collectively, the data indicate that the C-terminal region of TRPC4 has responded to selection on NST thermoregulation during the diversification of eutherian mammals. The drivers of increased diversification of Trpc4 and interacting genes in bats remain to be determined.
Cornman (2025) Molecular evolution of TRPC4 regulatory sequences supports a role in mammalian thermoregulatory adaptation. PeerJ 13:e19697 https://doi.org/10.7717/peerj.19697