Ventilation strategies based on an aerodynamic analysis during a large-scale SARS-CoV-2 outbreak in an acute-care hospital.

BACKGROUND: This study aimed to investigate ventilation strategies to prevent nosocomial transmission of coronavirus disease 2019 (COVID-19). METHODS: We conducted a retrospective epidemiological investigation of a severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) outbreak in a teaching hospital (February-March 2021). The largest outbreak ward was studied, and measurements were taken to determine the pressure difference and air change per hour (ACH) of the rooms. Airflow dynamics were assessed using an oil droplet generator, indoor air quality sensor, and particle image velocimetry in the index patient's room, corridor, and opposite rooms, by varying the opening and closing of windows and doors. RESULTS: During the outbreak, 283 COVID-19 cases were identified. The SARS-CoV-2 spread occurred sequentially from the index room to the nearest room, especially the opposite. The aerodynamic study demonstrated that droplet-like particles in the index room diffused through the corridor and the opposite room through the opening door. The mean ACH of the rooms was 1.44; the air supply volume was 15.9% larger than the exhaust volume, forming a positive pressure. Closing the door prevented diffusion between adjacent rooms facing each other, and natural ventilation reduced the concentration of particles within the ward and minimised their spread to adjacent rooms. CONCLUSIONS: Spread of droplet-like particles between rooms could be attributed to the pressure difference between the rooms and corridor. To prevent spread of SARS-CoV-2 between rooms, increasing the ACH in the room by maximising ventilation and minimising the positive pressure through supply/exhaust control and closing the room door are essential.

Arthroscopic Implantation of Adipose-Derived Stromal Vascular Fraction Improves Cartilage Regeneration and Pain Relief in Patients With Knee Osteoarthritis.

Purpose: To compare the pain relief and cartilage repair status of patients with knee osteoarthritis who received arthroscopic treatment with or without stromal vascular fraction (SVF) implantation. Methods: We retrospectively evaluated the patients who were examined with 12-month follow-up magnetic resonance imaging (MRI) after arthroscopic treatment for knee osteoarthritis from September 2019 to April 2021. Patients were included in this study if they had grade 3 or 4 knee osteoarthritis according to the Outerbridge classification in MRI. The visual analog scale (VAS) was used for pain assessment over the follow-up period (baseline and at 1-, 3-, 6-, and 12-month follow-ups). Cartilage repair was evaluated using follow-up MRIs based on Outerbridge grades and the Magnetic Resonance Observation of Cartilage Repair Tissue scoring system. Results: Among 97 patients who received arthroscopic treatment, 54 patients received arthroscopic treatment alone (conventional group) and 43 received arthroscopic treatment along with SVF implantation (SVF group). In the conventional group, the mean VAS score decreased significantly at 1-month post-treatment compared with baseline (P < .05), and gradually increased from 3 to 12 months' post-treatment (all P < .05). In the SVF group, the mean VAS score decreased until 12 months post-treatment compared with baseline (all P < .05 except P = .780 in 1-month vs 3-month follow-ups). Significantly greater pain relief was reported in the SVF group than in the conventional group at 6 and 12 months' post-treatment (all P < .05). Overall, Outerbridge grades were significantly greater in the SVF group than in the conventional group (P < .001). Similarly, mean Magnetic Resonance Observation of Cartilage Repair Tissue scores were significantly greater (P < .001) in the SVF group (70.5 ± 11.1) than in the conventional group (39.7 ± 8.2). Conclusions: The results regarding pain improvement and cartilage regeneration and the significant correlation between pain and MRI outcomes at 12-months follow-up indicate that the arthroscopic SVF implantation technique may be useful for repairing cartilage lesions in knee osteoarthritis. Level of Evidence: Level III, retrospective comparative study.

Cartilage lesion size and number of stromal vascular fraction (SVF) cells strongly influenced the SVF implantation outcomes in patients with knee osteoarthritis.

PURPOSE: This study evaluated outcomes in patients with knee osteoarthritis following stromal vascular fraction implantation and assessed the associated prognostic factors. METHODS: We retrospectively evaluated 43 patients who underwent follow-up magnetic resonance imaging 12 months after stromal vascular fraction implantation for knee osteoarthritis. Pain was assessed using the visual analogue scale and measured at baseline and 1-, 3-, 6-, and 12-month follow-up appointments. In addition, cartilage repair was evaluated based on the Magnetic Resonance Observation of Cartilage Repair Tissue scoring system using the magnetic resonance imaging from the 12-month follow-up. Finally, we evaluated the effects of various factors on outcomes following stromal vascular fraction implantation. RESULTS: Compared to the baseline value, the mean visual analogue scale score significantly and progressively decreased until 12 months post-treatment (P < 0.05 for all, except n.s. between the 1 and 3-month follow-ups). The mean Magnetic Resonance Observation of Cartilage Repair Tissue score was 70.5 ± 11.1. Furthermore, the mean visual analogue scale and Magnetic Resonance Observation of Cartilage Repair Tissue scores significantly correlated 12 months postoperatively (P = 0.002). Additionally, the cartilage lesion size and the number of stromal vascular fraction cells significantly correlated with the 12-month visual analogue scale scores and the Magnetic Resonance Observation of Cartilage Repair Tissue score. Multivariate analyses determined that the cartilage lesion size and the number of stromal vascular fraction cells had a high prognostic significance for unsatisfactory outcomes. CONCLUSION: Stromal vascular fraction implantation improved pain and cartilage regeneration for patients with knee osteoarthritis. The cartilage lesion size and the number of stromal vascular fraction cells significantly influenced the postoperative outcomes. Thus, these findings may serve as a basis for preoperative surgical decisions. LEVEL OF EVIDENCE: IV.

Steady amelioration of institutional hand hygiene behavior among health care personnel after 12-year consistent intervention.

BACKGROUND: Institutional hand hygiene (HH) behavior is difficult to monitor and improve consistently, especially over long periods. This study aimed to investigate the long-term effects of HH promotion activities. METHOD: We launched the HH promotion team in 2010 and conducted interventions including goal setting, observation and feedback, education, reward incentives, and accountability. Optimal HH compliance rates were calculated based on adherence to all 6-step HH technique and appropriate time recommended by the World Health Organization. HH and optimal HH compliance were calculated over 12 years. Poisson regression analysis was used to determine the trend in HH compliance according to year. RESULTS: In 2010, HH and optimal HH compliance were 59.7% and 15.6%, respectively. HH compliance increased by 83.9% in 2013 and remained over 75%. HH compliance increased significantly, with a relative risk (RR) of 1.014 (95% CI 1.002-1.025, P = .018). Optimal HH compliance increased by 67.8% in 2013 and remained over 60%, except in 2016 (58.8%) and 2019 (59.8%). Optimal HH compliance increased with RR 1.033 (95% CI 0.991-1.076, P = .123). DISCUSSION: HH and optimal HH compliance increased significantly over the 12 years when subgroup analysis was performed by job category. CONCLUSIONS: HH promotion team activities improved and maintained optimal HH compliance among HCWs.

A SARS-CoV-2 outbreak associated with vaccine breakthrough in an acute care hospital.

BACKGROUND: We aimed to analyze an outbreak caused by a vaccine breakthrough infection in a hospital with an active infection control program where 91.9% of health care workers were vaccinated. METHODS: We investigated a SARS-CoV-2 outbreak between September 9 and October 2, 2021, in a referral teaching hospital in Korea. We retrospectively collected data on demographics, vaccination history, transmission, and clinical features of confirmed coronavirus disease 2019 (COVID-19) in patients, health care workers, and caregivers. RESULTS: During the outbreak, 94 individuals tested positive for SARS-CoV-2 using reverse transcription-polymerase chain reaction testing. There were infections in 61 health care workers, 18 patients, and 15 caregivers; 74.5% (70/94) were vaccine breakthrough infections. Most transmissions appeared to be caused by three index cases, which accounted for 86.2% (81/94) of transmissions. Forty-seven (58.0%, 47/81) cases were associated with the hospital staff cafeteria and offices located in the basement. Among health care workers and caregivers, only one required oxygen supplementation. In contrast, among patients, there were four fatal cases (22.2%, 4/18), 3 of which were unvaccinated. CONCLUSIONS: Superspreading infection among fully vaccinated individuals occurred in an acute care hospital while the delta variant was dominant. Given the potential for severe complications, as this outbreak demonstrated, preventive measures including adequate ventilation should be emphasized to minimize transmission in hospitals.

Scope of a weekly infection control team rounding in an acute-care teaching hospital: a pilot study.

Regular and well-organized inspection of infection control is an essential element of an infection control program. The aim of this study was to identify the functional scope of weekly infection control team rounding (ICTR) in an acute care hospital. We conducted weekly ICTR between January 18 and December 26, 2018 to improve the compliance to infection control and prevention measures at a 734-bed academic hospital in the Republic of Korea and analyzed the results retrospectively. We categorized the results into five groups: "well maintained," "improvement needed," "long-term support, such as space or manpower, needed," "not applicable," or "could not be observed". A total of nine categories and 85 sub-elements of infection control and prevention practices were evaluated. The median number of infection control team (ICT) visits per department was 7 (interquartile range [IQR]: 6-7). The ICT assessed a median of 16 elements (IQR: 12-22), and a total of 7452 results were obtained. Of those, 75% were monitored properly, 22% were "not applicable", and 4% were difficult to observe. The most common practices that were difficult to observe were strategies to prevent catheter-related surgical site infections, pneumonia, and occupationally acquired infections as well as injection safety practices. Although the ICTR was able to maintain regular visits to each department, further strategies beyond regular ICTR are needed to reduce category of "could not observed". This pilot study may provide an important reference for institutional infection prevention practices as it is the first study to investigate the functional coverage of ICTR.

Oral immunisation of mice with transgenic rice calli expressing cholera toxin B subunit fused to consensus dengue cEDIII antigen induces antibodies to all four dengue serotypes.

Dengue virus (DENV) infection is an emerging global health threat. DENV consists of four distinct serotypes, necessitating a tetravalent vaccine. In this study, expression of consensus envelope protein domain III (cEDIII) fused to cholera toxin B subunit (CTB) in transgenic rice calli was improved using the luminal binding protein BiP at the N-terminus and the SEKDEL signal sequences at the C-terminus, targeting the recombinant protein to endoplasmic reticulum (ER). We found that the fusion protein showed higher levels of expression when compared to the fusion proteins using rice amylase 3D (RAmy3D) or CTB native signal sequence only. The CTB-cEDIII fusion protein was evaluated as an oral dengue vaccine candidate in mice. Serotype specific systemic IgG antibodies and specific IgA response in feces were detected and furthermore, T cell proliferation and high frequency antibody-secreting B cells were detected in the spleen. These results suggest the possible use of plant-based dengue tetravalent vaccine targeted to the mucosal immune system for induction of systemic and mucosal immune responses to DENV infection.

Effects of hypotaurine on substantia gelatinosa neurons of the trigeminal subnucleus caudalis in immature mice.

To understand the action and mechanism of hypotaurine, an immediate precursor of taurine, on orofacial nociceptive processing, we examined the direct effects and receptor types involved in hypotaurine-induced responses using the whole-cell patch clamp technique in the substantia gelatinosa (SG) neurons of the trigeminal subnucleus caudalis (Vc) of immature mice. Under the condition of high-chloride pipette solution, hypotaurine elicited inward currents or upward deflections of membrane potential, which increased in a concentration-dependent manner (30-3000 µM) with the EC50 of 663.8 and 337.6 µM, respectively. The responses to 300 µM hypotaurine were reproducible and recovered upon washout. The 300 µM hypotaurine-induced currents were maintained in the presence of TTX, CNQX, and AP5, indicating direct postsynaptic action of hypotaurine on SG neurons. Responses to both low (300 µM) and high (1 or 3 mM) concentrations of hypotaurine were completely and reversibly blocked by the glycine receptor antagonist strychnine (2 µM), but unaffected by the GABAA receptor antagonist gabazine (3 µM) which blocks synaptic GABAA receptors at low concentration. Furthermore, responses to 300 µM hypotaurine and a maximal concentration of glycine (3 mM) were not additive, indicating that hypotaurine and glycine act on the same receptor. Hypotaurine-induced currents were partially antagonized by picrotoxin (50 µM) which blocks homomeric glycine receptors and by bicuculline (10 µM) which is an antagonist of α2 subunit-containing glycine receptors. These results suggest that hypotaurine-induced responses were mediated by glycine receptor activation in the SG neurons and hypotaurine might be used as an effective therapeutics for orofacial pain.

Baicalin Activates Glycine and γ-Aminobutyric Acid Receptors on Substantia Gelatinosa Neurons of the Trigeminal Subsnucleus Caudalis in Juvenile Mice.

The substantia gelatinosa (SG) of the trigeminal subnucleus caudalis (Vc) receives nociceptive afferent inputs from thin-myelinated A[Formula: see text] fibers and unmyelinated C fibers and has been shown to be involved in the processing of orofacial nociceptive information. Scutellaria baicalensis Georgi (Huang-Qin, SbG), one of the 50 fundamental herbs of Chinese herbology, has been used historically as anti-inflammatory and antineoplastic medicine. Baicalin, one of the major compounds of SbG, has been reported to have neuroprotective, anti-inflammatory and analgesic effects. However, the receptor type activated by baicalin and its precise action mechanism on the SG neurons of Vc have not yet been studied. The whole-cell patch clamp technique was performed to examine the ion channels activated by baicalin on the SG neurons of Vc. In high Cl[Formula: see text] pipette solution, the baicalin (300[Formula: see text][Formula: see text]M) induced repeatable inward currents ([Formula: see text][Formula: see text]pA, [Formula: see text]) without desensitization on all the SG neurons tested. Further, the inward currents showed a concentration (0.1-3[Formula: see text]mM) dependent pattern. The inward current was sustained in the presence of tetrodotoxin (0.5[Formula: see text][Formula: see text]M), a voltage sensitive Na[Formula: see text] channel blocker. In addition, baicalin-induced inward currents were reduced in the presence of picrotoxin (50[Formula: see text][Formula: see text]M), a GABAA receptor antagonist, flumazenil (100[Formula: see text][Formula: see text]M), a benzodiazepine-sensitive GABAA receptor antagonist, and strychnine (2[Formula: see text][Formula: see text]M), a glycine receptor antagonist, respectively. These results indicate that baicalin has inhibitory effects on the SG neurons of the Vc, which are due to the activation of GABAA and/or the glycine receptor. Our results suggest that baicalin may be a potential target for orofacial pain modulation.

Production of functional human vascular endothelial growth factor(165) in transgenic rice cell suspension cultures.

Vascular endothelial growth factors (VEGFs) are secreted by tumor cells and other cells exposed to hypoxia, and play a critical role in the development and differentiation of the vascular system. In this study, we investigated the production of functional recombinant human VEGF165 (rhVEGF165) in transgenic rice cell suspension culture. Complementary DNA was synthesized from human leukemia HL60 cells and cloned into expression vectors under the control of the rice α-amylase 3D (RAmy3D) promoter. The rice seed (Oryza sativa L. cv. Dongjin) was transformed with this recombinant vector by the Agrobacterium mediated method and the integration of the target gene into the plant genome was confirmed by genomic PCR. The expression of rhVEGF165 in the rice cells was determined by Northern blot and Western blot analyses. The accumulated rhVEGF165 protein in the culture medium was 19 mg/L after 18 days of culturing in a sugar-free medium. The rhVEGF165 was purified using a heparin HP column and its biological activity was tested on human umbilical vein endothelial cells (HUVECs). The purified rhVEGF165 significantly increased the proliferative activity of the HUVECs. Therefore, it was demonstrated that functional rhVEGF165 could be produced using transgenic rice suspension culture vector under the control of the RAmy3D promoter.