Radiographic features of COVID-19 based on an initial cohort of 96 patients in Singapore

INTRODUCTIONChest radiographs (CXRs) are widely used for the screening and management of COVID-19. This article describes the radiographic features of COVID-19 based on an initial national cohort of patients.METHODSThis is a retrospective review of swab-positive patients with COVID-19 who were admitted to four different hospitals in Singapore between 22 January and 9 March 2020. Initial and follow-up CXRs were reviewed by three experienced radiologists to identify the predominant pattern and distribution of lung parenchymal abnormalities.RESULTSIn total, 347 CXRs of 96 patients were reviewed. Initial CXRs were abnormal in 41 (42.7%) out of 96 patients. The mean time from onset of symptoms to CXR abnormality was 5.3 ± 4.7 days. The predominant pattern of lung abnormality was ground-glass opacity on initial CXRs (51.2%) and consolidation on follow-up CXRs (51.0%). Multifocal bilateral abnormalities in mixed central and peripheral distribution were observed in 63.4% and 59.2% of abnormal initial and follow-up CXRs, respectively. The lower zones were involved in 90.2% of initial CXRs and 93.9% of follow-up CXRs.CONCLUSIONIn a cohort of swab-positive patients, including those identified from contact tracing, we found a lower incidence of CXR abnormalities than was previously reported. The most common pattern was ground-glass opacity or consolidation, but mixed central and peripheral involvement was more common than peripheral involvement alone.     

New discoveries and directions for medical, dental and dental hygiene research: low temperature atmospheric pressure plasma

Abstract:  The study of plasma integrates physics, chemistry, biology, and engineering, and has recently engaged medicine and dental hygiene in research efforts. The study of plasma holds promise for a myriad of applications ranging from lasers and electronics, hazardous waste management, decontamination, sterilization and disinfection of foods, soil, water, instruments, to medical uses in wound healing and treating certain types of tumours and cancers. Plasma represents a new state-of-the-art sterilization and disinfection treatment for certain oral and enviornmental pathogens, heat-sensitive materials, contaminated medical waste, hard and soft surfaces, and ventilation systems may assist health care facilities in the management of various health concerns. The role that Low Temperature Atmospheric Pressure Plasma (LTAPP) could play in the inactivation of pathogenic microorganisms might prove to be a new, faster, noncorrosive, more economical alternative, as well as support green healthcare.     

O等位基因引起ABO基因型与表现型定型差异

保证输血时血清学方面的安全,首要的是对受血者与献血者ABO血型定型,血清学检查通常分两个步骤.正定型通常使用鼠源单克隆抗体检测红细胞表面是否存在A或B抗原.互补的实验即反定型,利用当红细胞上缺乏A或B抗原时,人群可天然产生相对应的抗体的原理,检测血清中是否存在抗-A或者抗-B抗体.确定了受血者红细胞表面的ABO抗原以及血浆中的抗体,便能确定血型,为其提供相合的血液.     

C-Kit and Its Ligand Stem Cell Factor: Potential Contribution to Prostate Cancer Bone Metastasis

The tyrosine kinase receptor c-kit and its ligand stem cell factor (SCF) have not been explored in prostate cancer (PC) bone metastasis. Herein, we found that three human PC cell lines and bone marrow stromal cells express a membrane-bound SCF isoform and release a soluble SCF. Bone marrow stromal cells revealed strong expression of c-kit, whereas PC cells showed very low levels of the receptor or did not express it all. Using an experimental model of PC bone metastasis, we found that intraosseous bone tumors formed by otherwise c-kit-negative PC3 cells strongly expressed c-kit, as demonstrated using immunohistochemical and Western blot analyses. Subcutaneous PC3 tumors were, however, c-kit-negative. Both bone and subcutaneous PC3 tumors were positive for SCF. Immunohistochemical analysis of human specimens revealed that the expression frequency of c-kit in epithelial cells was of 5% in benign prostatic hyperplasia, 14% in primary PC, and 40% in PC bone metastases, suggesting an overall trend of increased c-kit expression in clinical PC progression. Stem cell factor expression frequency was more than 80% in all the cases. Our data suggest that the bone microenvironment up-regulates c-kit expression on PC cells, favoring their intraosseous expansion.     

Rapid decrease in tuberculin skin test reactivity at preschool age after newborn vaccination

A study of tuberculin sensitivity was performed in 353 children aged 4-6 years, all vaccinated at birth with British BCG vaccine. Significant waning of tuberculin reactions with increasing age was found (p < 0.05). In the age group < 4.5 years, the mean tuberculin reaction was 6.6 mm, in the age group 4.5-5.5 years 5.2 mm and in the age group of > 5.5 years 3.5 mm. The number of children with positive reactions (> or = 5 mm) was 165 (40%) and those with strong reactions (> or = 10 mm) 49 (14%). None of the latter children had active tuberculosis during a follow-up period of 12 months. Eighty-three (24%) of the children had no reaction. The children who had been revaccinated with the MPR vaccine against measles, rubella and parotitis (n = 31) had significantly larger tuberculin reactions than the non-revaccinated children. Atopic dermatitis or infections during the preceding six months did not have any significant influence on reaction sizes. Our results demonstrate that the variation in size of tuberculin reactions after BCG vaccination at birth is large. We conclude that tuberculin sensitivity wanes rapidly by the age of 4.0-6.3 years.     

Feeding during acute diarrhea as a risk factor for persistent diarrhea

Dietary intake during diarrhea in children less than three years of age was estimated from information recorded on illustrated dietary forms used by children's caretakers during the first week of illness in a prospective community-based study of diarrheal diseases in Lima, Peru. The frequency of consumption and the amount consumed of food groups and selected commonly consumed foods were analyzed by the final duration of the diarrheal episode. Cereals were less frequently consumed during the acute phase of diarrheal episodes that ultimately became persistent (>14 days'duration), apparently shortening the duration of the episode by one day (median duration of four days in children not consuming vs three days in children consuming cereals during diarrhea, p <0.02 Kaplan-Meier logrank test). Only roots and tubers (mainly potatoes) were consumed in greater quantity during episodes that became persistent. There was no evidence that consumption of breast milk or non-maternal milk was associated with an alteration in diarrheal duration. This study provides further evidence of the beneficial effects of continuing feeding during diarrhea using foods available at the home level, especially cereals, which are commonly used in the diet of young children.     

Role of Moraxella (Branhamella) catarrhalis as a respiratory pathogen in children

During a 12-month surveillance period in 1981-1982, Moraxella catarrhalis was detected in cultures from nasopharyngeal aspirates from 76 (17%) of 449 children hospitalized with middle or lower respiratory tract infection. Seroconversion to M. catarrhalis was positive in 4(5%) of the 76 patients with M. catarrhalis present in nasopharyngeal aspirates and in 4(1%) of 373 patients with a negative finding. Although children with respiratory tract infections were often colonized by the organism, this was rarely the infective agent of the middle or lower airways. Four of 8 patients with seroconversion to M. catarrhalis exhibited a concomitant RSV infection. The carriage of this species was more closely associated with parainfluenza virus infections. Serological responses to M. catarrhalis were not associated with acute otitis media, and were also rare in children with pneumonia. It is concluded that bronchopulmonary infections caused by M. catarrhalis are rare in children, and that M. catarrhalis aetiology need not be considered in the selection of antibiotics in cases of community-acquired pneumonia or other infections of the middle or lower respiratory tract affecting primarily healthy children.