Factors influencing SARS-CoV-2 transmission and outbreak control measures in densely populated settings.

Starting with a handful of SARS-CoV-2 infections in dormitory residents in late March 2020, rapid transmission in their dense living environments ensued and by October 2020, more than 50,000 acute infections were identified across various dormitories in Singapore. The aim of the study is to identify combination of factors facilitating SARS-CoV-2 transmission and the impact of control measures in a dormitory through extensive epidemiological, serological and phylogenetic investigations, supported by simulation models. Our findings showed that asymptomatic cases and symptomatic cases who did not seek medical attention were major drivers of the outbreak. Furthermore, each resident had about 30 close contacts and each infected resident spread to 4.4 (IQR 3.5-5.3) others at the start of the outbreak. The final attack rate of the current outbreak was 76.2% (IQR 70.6-98.0%) and could be reduced by further 10% under a modified dormitory housing condition. These findings are important when designing living environments in a post COVID-19 future to reduce disease spread and facilitate rapid implementation of outbreak control measures.

Coracoid bone graft osteolysis after Latarjet procedure: A comparison study between two screws standard technique vs mini-plate fixation.

AIMS: One of the reason for Latarjet procedure failure may be coracoid graft osteolysis. In this study, we aimed to understand if a better compression between the coracoid process and the glenoid, using a mini-plate fixation during the Latarjet procedure, could reduce the amount of coracoid graft osteolysis. MATERIALS AND METHODS: A computed tomography scan analysis of 26 prospectively followed-up patients was conducted after modified Latarjet procedure using mini-plate fixation technique to determine both the location and the amount of coracoid graft osteolysis in them. We then compared our current results with results from that of our previous study without using mini-plate fixation to determine if there is any statistical significant difference in terms of corcacoid bone graft osteolysis between the two surgical techniques. RESULTS: The most relevant osteolysis was represented by the superficial part of the proximal coracoid, whereas the deep part of the proximal coracoid graft is least involved in osteolysis and has best bone healing. The current study showed a significant difference only for the deep part of the distal coracoid with our previous study (P < 0.01). DISCUSSION: To our knowledge, there are no studies in literature that show the causes of coracoid bone graft osteolysis after Latarjet procedure. CONCLUSION: Our study suggests that there is a significant difference only for the deep part of the distal coracoid in terms of osteolysis. At clinical examination, this difference did not correspond with any clinical findings. LEVEL OF EVIDENCE: Level 4. CLINICAL RELEVANCE: Prospective case series, Treatment study.

Coracoid graft osteolysis after the Latarjet procedure for anteroinferior shoulder instability: a computed tomography scan study of twenty-six patients.

BACKGROUND: The Latarjet procedure has been advocated as an option for the treatment of anteroinferior shoulder instability in certain patients. However, progression of the transferred coracoid bone graft to osteolysis has been reported in the literature. We propose that the coracoid bone graft osteolysis could be one of the causes of failure of the Latarjet procedure. MATERIALS AND METHODS: A computed tomography scan analysis was done of 26 patients prospectively followed-up after the Latarjet procedure to determine the location and the amount of the coracoid graft osteolysis. RESULTS: The most relevant osteolysis was represented by the superficial part of the proximal coracoid, whereas the distal region of the coracoid bone graft, especially in the deep portion, was the least involved in osteolysis and had the best bone healing. DISCUSSION: To our knowledge, this is the first study to quantify and localize coracoid osteolysis after Latarjet procedure for anteroinferior shoulder instability using CT scan analysis. CONCLUSION: Our study suggests that the bone-block effect from the Latarjet procedure may not be the principal effect in its treatment of anteroinferior shoulder instability in patients without significant bony defects.

Chronic exposure to TNF-alpha increases airway mucus gene expression in vivo.

BACKGROUND: Hypersecretion of mucus plays an important role in the pathogenesis and severity of asthma. The primary proteins in mucus are mucin glycoproteins; MUC-5AC is the primary airway mucin gene. The calcium chloride-activated channel gene hCLCA1 (gob-5 in the mouse) has been suggested to increase MUC-5AC gene expression, and both are increased in asthmatic patients and murine models. TNF-alpha increases the expression of these genes in vitro but has not been investigated in vivo. OBJECTIVE: We sought to determine whether TNF-alpha increases gene expression of gob-5 and MUC-5AC and induces mucus cell metaplasia in vivo. METHODS: Naive BALB/c mice received 50 ng of recombinant murine TNF-alpha (rmTNF-alpha) intratracheally daily for 1, 2, or 3 weeks; another group received the same dose of intratracheal rmTNF-alpha daily for 3 weeks and then alternate-day treatment for 3 additional weeks (total of 6 weeks). AKR mice received 50 ng of rmTNF-alpha intratracheally for 3 or 6 weeks daily. Naive nontreated mice were used as control animals. Airway gene products for gob-5 and MUC-5AC were determined by means of real-time PCR. Lung tissue sections were stained with periodic acid-Schiff/Alcian blue to assess mucus cell metaplasia. RESULTS: rmTNF-alpha significantly increased gene expression of airway gob-5 and MUC-5AC after 2 weeks in the BALB/c mice. There was noticeable mucus staining in all mice treated for at least 3 weeks with TNF-alpha and in 80% of the mice receiving 2 weeks of treatment. After 3 weeks of treatment, the AKR mice also showed increased gob-5 expression. CONCLUSIONS: This study demonstrates for the first time that TNF-alpha alone in vivo is sufficient to increase airway mucus gene expression in 2 murine strains.