Dissecting the Role of VicK Phosphatase in Aggregation and Biofilm Formation of Streptococcus mutans.

VicRK (WalRK or YycFG) is a conserved 2-component regulatory system (TCS) that regulates cell division, cell wall biosynthesis, and homeostasis in low-GC Gram-positive bacteria. VicRK is also associated with biofilm formation of Streptococcus mutans on the tooth surface as it directly regulates the extracellular polysaccharide (EPS) synthesis. Of the 2 components, VicK possesses both autokinase and phosphatase activities, which regulate the phosphorylation and dephosphorylation of the regulator VicR in response to environmental cues. However, the dual mechanism of VicK as the autokinase/phosphatase in regulating S. mutans' responses is not well elucidated. Previously, it has been shown that the phosphatase activity depends on the PAS domain and residues in the DHp domain of VicK in S. mutans. Specifically, mutating proline at 222 in the PAS domain inhibits VicK phosphatase activity. We generated a VicKP222A mutant to determine the level of VicR-P in the cytoplasm by Phos-tag sodium dodecyl sulfate polyacrylamide gel electrophoresis. We show that in VicKP222A phosphatase, attenuation increased phosphorylated VicR (VicR-P) that downregulated glucosyltransferases, gtfBC, thereby reducing the synthesis of water-insoluble polysaccharides (WIS-EPS) in the biofilm. In addition, VicKP222A presented as long-rod cells, reduced growth, and displayed asymmetrical division. A major adhesin of S. mutans, SpaP was downregulated in VicKP222A, making it unable to agglutinate in saliva. In summary, we have confirmed that VicK phosphatase activity is critical to maintain optimal phosphorylation status of VicR in S. mutans, which is important for cell growth, cell division, EPS synthesis, and bacterial agglutination in saliva. Hence, VicK phosphatase activity may represent a promising target to modulate S. mutans' pathogenicity.

The COVID-19 effect: number of patients presenting to The Mid Yorkshire Hospitals OMFS team with dental infections before and during The COVID-19 outbreak.

This paper investigates the effect of the COVID-19 outbreak and closure of dental practices on the frequency and severity of dental infections presenting in our emergency department. We compared the mean number of daily emergency department referrals for dental abscesses in the two weeks prior to and following the Chief Dental Officer's statement advising general dental practitioners to cease routine appointments, the mean number decreased from 1 to 0.37. In contrast, the severity and requirement for admission of these infections rose from 35% to 80%. This highlights the importance of the provision of local urgent dental centres during the COVID-19 outbreak in order to reduce pressure on secondary and tertiary care centres.

[Clinical analysis of 555 outpatients with hand, foot and mouth diseases caused by different enteroviruses].

Objective: To study the clinical characteristics of outpatients with hand, foot and mouth disease (HFMD) caused by different serotypes of enteroviruses. Methods: This was a prospective study. From February 2017 to March 2018, 563 outpatients with HFMD were enrolled by systematic sampling in the Department of Infectious Diseases, Henan Children's Hospital. Throat swabs were collected to determine the serotypes via PCR. Demographic, clinical, and laboratory data were collected by standard questionnaire. All cases were followed up twice at 2 and 9 weeks after the initial outpatient visit through telephone interview. A total of 563 cases were enrolled and 555 (98.6%) cases were positive for human enteroviruses, including 338 (60.9%) males. Analyses were stratified by enterovirus serotypes, Chi square test or Fisher's exact test, Rank sum test was used for comparison among different groups. Results: The age of 555 cases was 24.2 (16.4, 41.3) months. Among them 44.0% (224 cases) were identified as coxsackievirus (CV)-A6, while 189 cases, 35 cases, 14 cases and 73 cases were identified as CV-A16, enterovirus (EV)-A71, CV-A10 and other serotypes, respectively. Fever (≥37.5 ℃) was present in 51.4% (285/555) of laboratory confirmed cases. The proportions of fever in cases of CV-A6 (68.9%(168/244)) and CV-A10 (12/14) were significantly higher than those in cases of CV-A16 (31.7%(60/189),χ(2)=57.344,14.313,both P=0.000), other serotypes (43.8%(32/73),χ(2)=15.101 and 8.242, P=0.000 and 0.004) and EV-A71 (37.1%(13/35), χ(2)=13.506 and 9.441, P=0.000 and 0.002) respectively. There was no significant difference between CV-A6 and CV-A10 in presentation of fever (χ(2)=1.785, P=0.182). There were 359 cases (64.7%) with eruptions in mouth, hands, feet and buttocks. Cases infected with EV-A71 had the highest proportions (74.3%(26/35)) of rash emerging simultaneously in mouth, hands, feet, and buttocks. The proportion in cases of CV-A16, CV-A6, CVA10 and other serotype were 73.5% (139/189), 61.9% (151/244), 7/14 and 49.3% (36/73), respectively. The proportion of rash on other parts of body, such as face, limbs or torso in cases infected with CV-A6 (16.8% (41/244)) was the higherest and the proportion in cases of CV-A16, EV-A71, CV-A10 or other serotypes were 8.5% (16/189) , 5.7% (2/35) , 1/14, 6.8% (5/73) , respectively. None of these cases developed serious complications. Desquamation occurred in 45.5% (179/393) cases 7.5 (5.0, 9.0) days after disease onset and 13.5% (53/393) cases showed onychomadesis 31.0 (18.0, 33.5) days after disease onset. The proportion of desquamation and onychomadesis associated with CV-A6 (64.2% (95/148) and 31.8% (47/148)) was significantly higher than CV-A16 (31.8% (49/154) and 1.3% (2/154), χ(2)=33.601 and 52.482, both P=0.000) and other serotypes (38.0%(19/50) and 6.0%(3/50),χ(2)=10.236 and 12.988, P=0.001 and 0.000). Desquamation appeared more in cases of CV-A6 than in cases of CV-A10 (2/11,χ(2)=9.386, P=0.002), with the proportion of onychomadesis higher in CV-A6 than in EV-A71 (3.3% (1/30),χ(2)=11.088, P=0.001). Conclusion: Clinical manifestation such as fever, rash emerging parts, desquamation and onychomadesis are different among outpatient HFMD cases infected with CV-A16, CV-A6, EV-A71, CV-A10 and other enteroviruses.

Fusion of Newcastle disease virus with liposomes: role of the lipid composition of liposomes.

We demonstrate here that fusion occurs between the membrane of the Newcastle disease virus (NDV) and liposomes. Fluorescence dequenching studies (using Rhodamine-bearing viral envelopes) revealed the mixing of the lipids constituting the viral and liposomal membrane. The digestion of internal viral proteins by trypsin-containing liposomes indicated the mixing of the internal aqueous compartments. This last assay is independent of exchange of lipids between liposomal and viral membrane in the absence of fusion. Investigation of the effects of liposomal composition indicated that the presence of phosphatidylethanolamine and gangliosides are essential to optimize fusion. The fact that the Newcastle disease virus membrane can fuse with liposome also confirms that fusion must be determined by the viral proteins and could be mostly independent of the nature or presence of the host proteins.

An instrument to assess the oral health status of nursing home residents.

This article presents data from the development and testing of an instrument to evaluate the oral health of nursing home residents by nursing personnel (RNs, LVNs, and CNAs). After the instrument was developed, nursing staff were taught to do a brief oral health status examination (BOHSE). Using the instrument, a dentist examined 100 residents; the examination was repeated on the same residents by each category of nurse examiners. Correlation coefficients indicate that statistically significant interrater reliability between the three categories of nursing personnel and the dentist was established, suggesting that nursing staff can be taught to evaluate the oral health of residents. Replication of the study in multiple sites is recommended.

Estimation of actual caries prevalence and treatment needs from field survey caries information on a child population in U.S.A.

Caries scores (DT + Dt) were recorded under simulated field survey conditions on 270 children ranging in age from 3 to 12 years. The children were subsequently diagnosed under optimum clinical conditions. The findings from the field and clinical examinations were statistically analyzed to determine the relationships between "survey" and "true" caries scores. It is proposed that the true mean caries score can be estimated from the survey mean score by adding 1.5 teeth in the primary dentition and 2 teeth in the mixed dentition. Tables were devised to estimate treatment needs for children at various survey caries scores in each dentition category.

The internal ventricular venting loop catheter. A new, simplified, single cannulation approach for a ventricular assist system.

The internal ventricular venting loop (IVVL) catheter is a coaxial, two lumen, bidirectional flow cannula introduced peripherally and advanced intraluminally to the pulmonary artery by its flow directed, balloon tipped inner tubing in a right ventricular assist system (RVAS), or to the left ventricle over a guide wire under fluoroscopy in a left ventricular assist system (LVAS). Its use was successfully tested in six acute canine experiments using a small IVVL catheter. Hemodynamic responses to increasing roller pump flow rates, to a maximum of 1 L/min, were initially measured. Then, hemodynamic changes to 600 ml/min, after left anterior descending artery ligation (in IVVL-LVAS) and 300 ml/min after right coronary artery ligation (in IVVL-RVAS) were regularly recorded every 15 min until cardiac arrest. The IVVL-LVAS was able to significantly decrease the pulmonary capillary wedge pressure, while the IVVL-RVAS was able to significantly decrease the central venous pressure. The IVVL system was able to partially unload the ventricles and restore about 33-60% of the cardiac output. However, it could not effectively support the heart during arrest. Thus, the IVVL catheter can facilitate simple and effective single cannulation for either RVAS or LVAS. This approach may enable ordinary cardiac centers to make use of already available blood pumps for temporary, inexpensive, and less invasive application of partially assisted circulation when intra aortic balloon pump assistance fails.

An assessment of epilepsy patients' knowledge of their disorder.

PURPOSE: Patient education is an effective component of comprehensive care. Studies assessing patient's knowledge of their epilepsy are scarce. We report the first objective study evaluating knowledge of epilepsy patients referred to an American tertiary care center. METHODS: Two hundred twenty epilepsy patients referred to an epilepsy center completed a knowledge questionnaire. The questionnaire included topics related to safety, compliance, and legal issues of driving and employment. Questionnaire scores were correlated with demographics, number of years with epilepsy, and educational background. RESULTS: Of 220 patients, 175 were included in study analysis. Thirteen percent (n = 28) were excluded because of the diagnosis of nonepileptic seizures, and 8% (n = 17) were excluded because of having a diagnosis other than epilepsy. The average age and number of years with epilepsy was 34.7 +/- 13 and 14. 4 +/- 13.1, respectively. Neither age (r = 0.20, p