Simulation of pandemics in real cities: enhanced and accurate digital laboratories

This study develops a modelling framework for simulating the spread of infectious diseases within real cities. Digital copies of Birmingham (UK) and Bogotá (Colombia) are generated, reproducing their urban environment, infrastructure and population. The digital inhabitants have the same statistical features of the real population. Their motion is a combination of predictable trips (commute to work, school, etc.) and random walks (shopping, leisure, etc.). Millions of individuals, their encounters and the spread of the disease are simulated by means of high-performance computing and massively parallel algorithms for several months and a time resolution of 1 minute. Simulations accurately reproduce the COVID-19 data for Birmingham and Bogotá both before and during the lockdown. The model has only one adjustable parameter calculable in the early stages of the pandemic. Policymakers can use our digital cities as virtual laboratories for testing, predicting and comparing the effects of policies aimed at containing epidemics.

Pharmacokinetics and serum concentrations of antimycobacterial drugs in adult Turkish patients

OBJECTIVE

To document the pharmacokinetics and serum concentrations of first-line anti-tuberculosis drugs in adult Turkish patients with pulmonary tuberculosis (PTB).

DESIGN

Consenting 21 adult patients (aged 38 ± 4 years, 10 female and 11 male) with newly diagnosed active PTB participated in the study. Blood samples were collected 1, 2, 4, 6 and 24 h after simultaneous isoniazid (INH), rifampicin (RMP), pyrazinamide (PZA) and ethambutol (EMB) ingestion. Serum concentration-time profiles, maximum serum concentrations, time to achieve maximum serum concentrations, the half-life and the areas under the serum concentration-time curve for each of the four drugs were determined.

RESULTS

Wide variations in pharmacokinetic parameters were observed among patients. In respectively 8 (38%), 17 (81%), 3 (14%) and 1 (5%) patients, the maximum INH, RMP, PZA and EMB serum concentrations were below the accepted therapeutic concentrations.

CONCLUSION

Our data show that the serum concentrations of anti-tuberculosis drugs varied considerably in the study patients. Therapeutic drug monitoring is necessary to identify patients with subtherapeutic INH and RMP serum concentrations.

Prevalence of egg sensitization in Turkish infants based on skin prick test

AIM

Egg allergy is one of the most frequent allergies in infants. The aim of this study was to determine the frequency of sensitization to egg in infants based on skin prick test results and to evaluate associated allergic conditions by questionnaire.

METHODS

All infants born between June 2001 and May 2002 were recalled to the hospital according to their dates of birth, and 1015 infants aged between 8-18 months were included in the study. An interview was conducted with each mother and a questionnaire requesting data on food allergy and other allergic diseases was completed during this interview. An egg skin prick test (whole egg) was applied to all infants.

RESULTS

Positive skin prick test results were recorded in 19 infants (1.87 %). There was no difference between the prick test-positive and -negative groups with respect to any of the demographic characteristics investigated (gender, age, birth weight, egg consumption, age of introduction of egg and other solids, breastfeeding). No significant association was demonstrated between sensitization to egg and family history of allergy. Moreover, there was no association between sensitization to egg and occurrence of atopic dermatitis, recurrent wheezing, gastrointestinal symptoms and doctor diagnosis of asthma.

CONCLUSION

The prevalence of egg sensitization based on skin prick test results has been found as 1.87 % among Turkish infants in Istanbul. However, no significant relationship was found between allergic sensitization to egg and occurrence of allergic diseases in this study population.

Predictors of early leaving from the cotton spinning mill environment in newly hired workers

OBJECTIVE

This longitudinal study aimed to identify the predictors of leaving during the first year of employment from the cotton spinning mill environment in newly hired workers.

METHODS

One hundred and ninety eight consecutively appointed new employees were investigated by questionnaire, lung function test, and skin test. They were examined before employment and at the end of the 1st week, and the 1st, 3rd, 6th, and 12th month after starting work and when possible before leaving their job. 572 personal dust sampling and 191 endotoxin measurements were performed to assess the environmental exposure. For the univariate analysis chi2, Student t tests, ANOVA, and Kruskall Wallis tests were used. Cox proportional hazards analysis was used to identify factors associated with leaving the job.

RESULTS

Fifty three per cent of workers left the mill environment during their first working year. Work related lower respiratory tract symptoms reported at the third month were associated with an increase rate of leaving the industry compared to those remaining in the industry (25% v 4.8%; p<0.005). Having respiratory symptoms at the first month of work predicted those leaving the industry at some point in the next 11 months. According to the Cox model, increasing age and having work related lower respiratory tract symptoms were found to be predictors for leaving job at the first working year. Atopic status, dust and endotoxin levels, and lung function changes were not consistently predictive of workers who left the industry in the follow up period.

CONCLUSION

This study demonstrated that work related respiratory symptoms can predict workers likely to leave the cotton mill environment during the first year of employment, but atopy or acute lung function changes do not.

The effects of quantum energy surgical device and of bipolar coagulation: a comparative experimental study

OBJECTIVE

The quantum energy surgical device (QESD) employs an innovative, "no-touch" thermal coagulation, incision and evaporation technique in which thermal energy is delivered to tissue in the format of high-energy neutral argon gas atoms. The aim of this study is to compare QESD and bipolar coagulation (BC) through assessment of both haemostasis and histological damage to isolated femoral arteries of rats.

METHODS

Sixty rats were randomly divided into acute and short-term experimental groups. In the acute group (n=20) histopathological evaluation was performed immediately following coagulation, whereas in the short-term experimental group (n=20) the evaluation was performed 10 days later. Each sham group consisted of ten rats. Viewed under the surgical microscope, only normal-appearing, freshly sectioned, and bleeding femoral arteries were studied. Right femoral arteries subject to QESD coagulation, and left femoral arteries to BC. Haemorrhaging was controlled using the minimal coagulation time necessary to stop it. All vascular layers, including endothelium, internal elastic lamina, media and adventitia were examined histologically and ultrastructurally in a "blind" fashion to critically compare morphological damage due to QESD and BC.

RESULTS

Surgical haemostasis induced by QESD was found to be as safe as BC. Light microscopy revealed more marked histopathological changes in the BC than in the QESD group. These involved mainly the endothelial and medial compartments and, at the ultrastructural level, consisted of endothelial degeneration and exfoliation, irregularity of internal elastic lamina, degeneration, and loss of medial smooth muscle.

CONCLUSION

The results indicate that QESD coagulation induces significantly less histological damage than does BC. Thus QESD coagulation is a safe, less tissue destructive, and equally effective method of haemostasis.