Study on the disinfection effect of chlorine dioxide disinfectant (ClO2) on dental unit waterlines and its in vitro safety evaluation.

BACKGROUND: Ensuring the safety of dental unit waterlines (DUWLs) has become a pivotal issue in dental care practices, focusing on the health implications for both patients and healthcare providers. The inherent structure and usage conditions of DUWLs contribute to the risk of biofilm formation and bacterial growth, highlighting the need for effective disinfection solutions.The quest for a disinfection method that is both safe for clinical use and effective against pathogens such as Staphylococcus aureus and Escherichia coli in DUWLs underscores the urgency of this research. MATERIALS: Chlorine dioxide disinfectants at concentrations of 5, 20, and 80 mg/L were used to treat biofilms of S. aureus and E. coli cultured in DUWLs. The disinfection effectiveness was assessed through bacterial counts and culturing. Simultaneously, human skin fibroblast cells were treated with the disinfectant to observe changes in cell morphology and cytotoxicity. Additionally, the study included corrosion tests on various metals (carbon steel, brass, stainless steel, aluminum, etc.). RESULTS: Experimental results showed that chlorine dioxide disinfectants at concentrations of 20 mg/L and 80 mg/L significantly reduced the bacterial count of S. aureus and E. coli, indicating effective disinfection. In terms of cytotoxicity, higher concentrations were more harmful to cellular safety, but even at 80 mg/L, the cytotoxicity of chlorine dioxide remained within controllable limits. Corrosion tests revealed that chlorine dioxide disinfectants had a certain corrosive effect on carbon steel and brass, and the degree of corrosion increased with the concentration of the disinfectant. CONCLUSION: After thorough research, we recommend using chlorine dioxide disinfectant at a concentration of 20 mg/L for significantly reducing bacterial biofilms in dental unit waterlines (DUWLs). This concentration also ensures satisfactory cell safety and metal corrosion resistance.

Paediatric atypical teratoid/rhabdoid tumour of the pineal region mimicking a meningioma: a case report and literature review.

PURPOSE: Atypical teratoid/rhabdoid tumour (AT/RT) is a highly malignant central nervous system tumour of early childhood. According to the latest WHO classification, the diagnosis of AT/RTs needs to be confirmed by the absence of SMARCB1 (INI1) or SMARCA4 (BRG1) protein expression. AT/RT in the pineal region is infrequent and most have not been proven genetically. Here, we report a case of AT/RT in the pineal region, preoperatively misdiagnosed as a meningioma. Immunohistochemistry revealed the absence of INI1 protein expression. METHOD: A 29-month-old boy was admitted to the hospital after 14 days of emotional apathy and a 2-day vomiting history. AT/RT was not considered during the initial diagnosis because this tumour is rare in this region and is often accompanied by cystic degeneration and necrosis on imaging. Subsequently, the patient underwent surgery and the tumour was completely excised. RESULT: The pathological diagnosis was AT/RT. After discharge, the patient continued chemotherapy in other hospitals but died five months after surgery because of disease progression. CONCLUSION: To our knowledge, this is the fifth case of paediatric pineal AT/RT confirmed genetically. Although in children AT/RT in the pineal gland is rare, a differential diagnosis of AT/RT should be considered when new pineal masses appear in children. For this highly malignant disease with poor prognosis, it is very important to detect and recognize the disease as soon as possible, and to adopt surgery plus multiple treatment management.

Combined detection of AFP-L3, GP73 and TIP30 enhances diagnostic accuracy for HBV-related cirrhosis and hepatocellular carcinoma.

OBJECTIVE: To investigate the value of combined tests of serum Golgi protein-73, alpha-fetoprotein- L3 and Tat-interacting protein-30 in the diagnosis of hepatitis B virus related cirrhosis and hepatocellular carcinoma. METHODS: The cross-sectional study was conducted at Yuebei People's Hospital, Guangdong, China, from January to October 2017, and comprised hepatitis B patients and healthy controls. Serum Golgi protein-73, alpha-fetoprotein-L3 and Tat-interacting protein-30 levels in both groups were detected by enzyme-linked immunosorbent assay (ELISA). Alpha-fetoprotein-L3 was separated and quantified by electrochemiluminescence immunoas says and the percentage of alpha-fetoprotein-L3 to alphafetoprotein was calculated. RESULTS: Of the 721 subjects, 525(%) were patients and 196(%) were healthy controls. Among the patients, 271(%) had chronic hepatitis B, 161(%) had liver cirrhosis and 93(%) had hepatocellular carcinoma. Serum Golgi protein-73, alpha-fetoprotein-L3 and Tat-interacting protein-30 levels were significantly different in the hepatocellular carcinoma patients compared to controls, and those with chronic hepatitis and liver cirrhosis (p<0.01 each). The sensitivity and specificity of the combined detection of the three serum levels for diagnosing cirrhosis were 78.26% and 86.72%. The corresponding values for diagnosing hepatocellular carcinoma were 86.02% and 92.51%. CONCLUSIONS: Combined detection of Golgi protein-73, alpha fetoprotein-L3 and Tat-interacting protein was found to have the potential to improve diagnostic accuracy.

Substrate Stiffness Modulates the Maturation of Human Pluripotent Stem-Cell-Derived Hepatocytes.

Obtaining functional hepatocytes from human pluripotent stem cells (hPSCs) holds great potential for applications in drug safety testing, as well in the field of regenerative medicine. However, developing functionally mature hPSC-derived hepatocytes (hPSC-Heps) remains a challenge. We hypothesized that the cellular microenvironment plays a vital role in the maturation of immature hepatocytes. In this study, we examined the role of mechanical stiffness, a key component of the cellular microenvironment, in the maturation of hPSC-Heps. We cultured hPSC-Heps on collagen-coated polyacrylamide hydrogels with varying elastic moduli. On softer substrates the hPSC-Heps formed compact colonies while on stiffer substrates they formed a diffuse monolayer. We observed an inverse correlation between albumin production and substrate stiffness. The expression of key cytochrome enzymes, which are expressed at higher levels in the adult liver compared to the fetal liver, also correlated inversely with substrate stiffness, whereas fetal markers such as Cyp3A7 and AFP showed no correlation with stiffness. Culture of hPSC-Heps on soft substrates for 12 days led to 10-30 fold increases in the expression of drug-metabolizing enzymes. These results demonstrate that substrate stiffness similar to that of the liver enables aspects of the maturation of hPSC-Heps.

Molecular cloning and characterization of hemoglobin alpha and beta chains from plateau pika (Ochotona curzoniae) living at high altitude.

Hemoglobin (Hb) plays an important role in oxygen transfer from lung to tissues. Possession of a Hb with high oxygen affinity helps highland animals to adapt to high altitude, has been studied profoundly. Plateau pika (Ochotona curzoniae), a native species living at 3,000-5,000 m above sea level on Qinghai-Tibet Plateau, is a typical hypoxia and low temperature tolerant mammal. To investigate the possible mechanisms of plateau pika Hb in adaptation to high altitude, the complete cDNA and amino acid sequences of plateau pika hemoglobin alpha and beta chains have been described. Compared with human Hb, alterations in important regions can be noted: alpha111 Ala-->Asn, beta35 Tyr-->Phe, beta112 Cys-->Val, beta115 Ala-->Ser, and beta125 Pro-->Gln. Phylogenetic analysis of alpha and beta chains shows that plateau pika is closer to rabbit than to other species. This study provides essential information for elucidating the possible roles of hemoglobin in adaptation to extremely high altitude in plateau pika.

Molecular cloning of hemoglobin alpha-chain gene from Pantholops hodgsonii, a hypoxic tolerance species.

To investigate the possible mechanisms of high-altitude native animals in adapting to high altitude, we cloned hemoglobin alpha-chain (alpha-chain Hb) gene from Pantholops hodgsonii, an animal species that indigenously lives at elevations of 3700-5500 m on the Qinghai-Tibetan plateau. Using reverse transcription polymerase chain reaction (RT-PCR) technique, the alpha-chain Hb gene was amplified from total RNA in the liver of the Pantholops hodgsonii. TA cloning technique was used and the PCR product was cloned into pGEM-T vector. The DNA sequence of the gene was highly homologous with sheep (99.1%), goat (98.6%), cattle (95.6%) and human (86.5%). The alpha-chain Hb gene encoded a 142-amino acid protein that could be identified with the homology of alpha-chain Hb protein in sheep (98%), goat (96%), cattle (91%) and human (87%). However, 18 alternations were detected when compared with the alpha-chain Hb gene in human, and 2 in sheep. Moreover, the alterations of á117 GluAsp and alpha 132 AsnSer in important regions were noted in human and sheep, respectively. Phylogenetic analysis suggested that the structure of alpha-chain Hb was highly similar to that in sheep. This study provided essential information for elucidating the possible roles of hemoglobin in adapting to extremely high altitude in Pantholops hodgsonii.

Determination of oridonin in rat plasma by reverse-phase high-performance liquid chromatography.

A method for quantitative determination of oridonin in rat plasma using reversed-phase high-performance liquid chromatography (RP-HPLC) coupled with UV spectrometry was established and the method was applied to a pharmacokinetics study of oridonin in rats. From a variety of compounds and solvents tested, ticolpidine was selected as the internal standard (IS) and ethyl acetate was found to be the best solvent for extracting oridonin from plasma samples. RP-HPLC analysis of the extracts was performed on an analytical column (DIKMA ODS, 200 mm x 4.6 mm; i.d., 5 microm) equipped with a security guard pre-column system. There was a good linearity over the range 0.05-8.0 microg/mL (r>0.99). The recoveries were about 95.0% in plasma, and the intra- and inter-day coefficients of variation were less than 9.0% in all cases. The limit of detection (LOD) was 0.025 microg/mL and the lower limit of quantification (LLOQ) was 0.05 microg/mL. The RP-HPLC method was readily applied to quantitate oridonin in rat plasma within 24 h in a pharmacokinetics study where experimental rats received a single dose of oridonin (12.5 mg/kg) and the result was presented.