Nanoplastics exacerbate Parkinson's disease symptoms in C. elegans and human cells.

The increasing prevalence of nanoplastics in our environment due to the widespread use of plastics poses potential health risks that are not yet fully understood. This study examines the physiological and neurotoxic effects of these minuscule nanoplastic particles on the nematode Caenorhabditis elegans as well as on human cells. Here, we find that 25 nm polystyrene nanoplastic particles can inhibit animal growth and movement at very low concentrations, with varying effects on their surface groups. Furthermore, these nanoplastic particles not only accumulate in the digestive tract but also penetrate further into extraintestinal tissues. Such nanoplastics significantly compromise the integrity of the intestinal barrier, leading to "leaky gut" conditions and cause mitochondrial fragmentation in muscles, which possibly explains the observed movement impairments. A striking discovery was that these nanoplastics exacerbate symptoms similar to those of Parkinson's disease (PD), including dopaminergic neuronal degeneration, locomotor dysfunction, and accumulation of α-Synuclein aggregates. Importantly, our study demonstrates that the detrimental effects of nanoplastics on the aggregation of α-Synuclein extend to both C. elegans and human cell models of PD. In conclusion, our research highlights the potential health hazards linked to the physicochemical properties of nanoplastics, underlining the urgency of understanding their interactions with biological systems. ENVIRONMENTAL IMPLICATION: The escalating prevalence of nanoplastics in the environment due to widespread plastic usage raises potential health risks. Studies conducted on C. elegans indicate that even low concentrations of 25 nm polystyrene nanoplastics can impair growth and movement. These particles accumulate in the digestive system, compromising the intestinal barrier, causing "leaky gut", as well as inducing Parkinson's-like symptoms. Importantly, in both C. elegans and human cell models of Parkinson's disease, such nanoplastics penetrate tissues or cells and increase α-Synuclein aggregates. This underscores the urgent need to understand the interactions of nanoplastics with biological systems and highlights potential environmental and health consequences.

Association Between Oral Health Status and Survival Time in Terminally Ill Cancer Patients.

INTRODUCTION: Patients with terminal cancer often experience various oral problems. Whether oral health status is associated with the survival of terminally ill cancer patients receiving palliative care remains unclear. METHODS: We analyzed the data of 59 Korean patients with terminal cancer receiving palliative care, including their oral health status, using a modified Korean version of the Oral Health Assessment Tool (OHAT). Patients were categorized into "Good," "Moderate," or "Poor" groups based on OHAT scores. The Kaplan-Meier method was used to compare the median survival time, and the prognosis between groups was estimated using Cox proportional hazard models. RESULTS: The most common oral symptoms observed were xerostomia (69.5%) and mucositis (17.0%). Significantly shorter survival times were observed in patients with hyperbilirubinemia, elevated creatinine levels, and no use of dentures. The "Poor" group had a shorter survival than the "Good" oral group (P = .010). A multivariate Cox proportional hazards analysis revealed that the "Poor" group was significantly associated with poor survival compared to the "Good" group (hazard ratio, 2.05; P = .047). CONCLUSION: Terminally ill cancer patients with poor oral health may have a higher risk of shorter survival. Palliative care professionals should pay attention to oral health. Further research is needed to determine the effects of oral care on survival.

Biosynthesis of polylactic acid and its copolymers using evolved propionate CoA transferase and PHA synthase.

For the synthesis of polylactic acid (PLA) and its copolymers by one-step fermentation process, heterologous pathways involving Clostridium propionicum propionate CoA transferase (Pct(Cp)) and Pseudomonas sp. MBEL 6-19 polyhydroxyalkanoate (PHA) synthase 1 (PhaC1(Ps6-19)) were introduced into Escherichia coli for the generation of lactyl-CoA endogenously and incorporation of lactyl-CoA into the polymer, respectively. Since the wild-type PhaC1(Ps6-19) did not efficiently accept lactyl-CoA as a substrate, site directed mutagenesis as well as saturation mutagenesis were performed to improve the enzyme. The wild-type Pct(Cp) was not able to efficiently convert lactate to lactyl-CoA and was found to exert inhibitory effect on cell growth, random mutagenesis by error-prone PCR was carried out. By employing engineered PhaC1(Ps6-19) and Pct(Cp), poly(3-hydroxybutyrate-co-lactate), P(3HB-co-LA), containing 20-49 mol% lactate could be produced up to 62 wt% from glucose and 3HB. By controlling the 3HB concentration in the medium, PLA homopolymer and P(3HB-co-LA) containing lactate as a major monomer unit could be synthesized. Also, P(3HB-co-LA) copolymers containing various lactate fractions could be produced from glucose alone by introducing the Cupriavidus necator beta-ketothiolase and acetoacetyl-CoA reductase genes. Fed-batch cultures were performed to produce P(3HB-co-LA) copolymers having 9-64 mol% of lactate, and their molecular weights, thermal properties, and melt flow properties were determined.

The effect of internal versus external abutment connection modes on crestal bone changes around dental implants: a radiographic analysis.

BACKGROUND: To the best of our knowledge, the influence of external versus internal implant-abutment connections on crestal bone remodeling has not been reported. The aim of the present study is to investigate the influence of the abutment connection on peri-implant crestal bone levels (CBLs) using radiographic recordings. METHODS: Radiographic recordings from 40 single-tooth implants (20 external and 20 internal octagonal connections; one implant/patient) in 40 patients (15 males and 25 females; mean age: 54.3 years) were selected for analyses. The radiographic evaluation included the following: 1) linear bone change (LBC); 2) dimensional change (DC); and 3) angle between the implant and adjacent bone (AIB). Differences in LBC, DC, and AIB between implant placement and 1 year after loading for each system were evaluated using a paired t test. Comparison of LBC, DC, and AIB between systems at 1 year after loading was done using analysis of covariance. The significance level was set at P ≤0.05. RESULTS: Radiographic CBLs (LBCs) were reduced at 1 year after loading compared to those at implant placement to reach statistical significance for the external connection (P = 0.000) but not the internal connection (P = 0.939). CBL changes were significantly greater for the external compared to the internal connection (P = 0.000). Similarly, the DC for the external connection was significantly greater compared to that for the internal connection (P = 0.004). CONCLUSION: Within the limitations of this study, the implant-abutment connection technology appears to have a significant impact on peri-implant CBLs, with the external connection paralleled by a significant reduction of CBLs.