Optimization of insect cell based protein production processes - online monitoring, expression systems, scale-up

Due to the increasing use of insect cell based expression systems in research and industrial recombinant protein production, the development of efficient and reproducible production processes remains a challenging task. In this context, the application of online monitoring techniques is intended to ensure high and reproducible product qualities already during the early phases of process development. In the following chapter, the most common transient and stable insect cell based expression systems are briefly introduced. Novel applications of insect cell based expression systems for the production of insect derived antimicrobial peptides/proteins (AMPs) are discussed using the example of G. mellonella derived gloverin. Suitable in situ sensor techniques for insect cell culture monitoring in disposable and common bioreactor systems are outlined with respect to optical and capacitive sensor concepts. Since scale-up of production processes is one of the most critical steps in process development, a conclusive overview is given about scale up aspects for industrial insect cell culture processes

Seroepidemiology of Varicella and value of self-reported history of Varicella infection in Iranian medical students

Objectives: We conducted this study to assess the seroprevalence of Varicella zoster virus (VZV) antibodies in a group of Iranian medical sciences students that were at risk of Varicella and the value of self-reported history as a predictor of immunity. Material and Methods: 255 medical, nursing and obstetrics students who had not entered as a student or worked in a hospital from 3 different schools were enrolled in the study in 2012 (Qazvin province, Iran). Demographics and other information as well as the history of Varicella were obtained through a self-administered questionnaire. Blood samples were collected to determine the Varicella IgG levels via an enzyme-linked immunosorbent assay. A statistical analysis was performed by calculating prevalences and their 95% confidence intervals. Sensitivity, specificity, positive and negative predictive values, Cohen's kappa and positive and negative likelihood ratios of recalled history were determined. p < 0.05 was considered statistically significant. Results: The mean age of participants was 21.3±4.3 years. Seropositivity rate was 74.5%. The relationships between marital status, number of family members, and acquired VZV history with immunity against the virus were statistically significant. The overall rate of reported history was 57%. The positive and negative predictive values of self-reported history of Varicella were 91% and 47.3%, respectively. Conclusions: Immunization of students of Iranian medical sciences seems logical in the near future. Also, they should be tested for Varicella immunity regardless of the history of previous infection

Neonatal BCG vaccination and tuberculin skin sensitivity among schoolchildren of the United Arab Emirates

A cross-sectional survey of 785 schoolchildren living in the Al An region was undertaken between January and June 1994 to assess the effect of neonatal BCG vaccination on tuberculin sensitivity and to study the risk of exposure to tuberculosis in the same population. A documented history of BCG vaccination was obtained in 547 (69.7%) schoolchildren. The prevalence of a 10 mm or greater induration of tuberculin skin reactivity varied from 8% in unvaccinated to 11.5% among vaccinated children. This was not statistically significant. Children living in urban areas irrespective of vaccination status had a higher rate of tuberculin reactivity than those living in rural areas (relative risk 5.77; 95% confidence interval 1.85-18.00; p<0.0004). The pattern and rate of tuberculin sensitivity were similar among the other socio-demographic standards investigated. Earlier BCG vaccination had no effect on subsequent tuberculin sensitivity of either negative (0.4 mm), intermediate (5-9 mm) or positive (greater than or equal to 10 mm) type skin reactions. It is concluded that the risk of exposure to tuberculous infection is several times higher among children living in urban areas than among those living in a rural environment. Earlier BCG vaccination should not interfere with diagnostic tuberculin skin sensitivity and is still a useful tool in assessing the risk of tuberculous infection in such populations

Factors associated with tuberculin reactivity among children in United Arab Emirates

A cross-sectional survey of tuberculin skin reactivity was conducted in Al-Ain, United Arab Emirates (U.A.E.) between January and June 1994, to find out the prevalence rate of tuberculosis infection. A pre-designed questionnaire was used to collect details of BCG scar, age, sex, residence area, nationality, education, type of house, number of rooms, family size and household contact history of tuberculosis, A total of 785 students were screened, of whom 547 gave a history of BCG vaccination in the past and 238 were BCG-negative. Among BCG-negative children aged 5-11 years and 12-15 years, only 6.5% and 9.3%, respectively, had a positive Mantoux reaction - a rate lower than most Third World countries, but higher than developed countries where under 2% of children are tuberculin reactors. A general linear model with positive Mantoux reaction as the dependent variable was fitted to the data to examine the joint effect of age, sex, residential area, number of rooms at home, family size and BCG vaccine history. The Mantoux reaction was entered as positive and a number of statistically significant associations were found between positive Mantoux test >10 mm and: age (P=0.0018); sex (P=0.0281); residential area (P10 mm). The prevalence (8%) in the 5-14 years age group puts U.A.E. between low (2%) and middle (14%) prevalence countries, according to the classification of the International Union Against Tuberculosis. This calls for continuation of free treatment of active cases and increased efforts towards screening of contacts

Toxoplasma antibody prevalence among healthy adults in United Arab Emirates

Objective: The aim of this study was to establish baseline data on the seroprevalence of toxoplasmosis and to assess some inherent and environmental risk factors that may be associated with toxoplasmosis among healthy adults in United Arab Emirates

Haemophilus influenzae type b still remains a leading cause of meningitis among unvaccinated children - A prospective CSF analysis study

A prospective, hospital-based cerebrospinal fluid (CSF) analysis study was undertaken in 65 children who had diagnostic lumbar puncture on admission for suspected central nervous system infections. Twenty-three children were clinically diagnosed to have had sepsis and/or meningitis. CSF bacterial culture grew Haemophilus influenzae type b (Hib) in four cases and Streptococcus pneumonia (SP) was cultured in another child. Bacterial antigen was detected in 13 other CSF specimens and the pathogens were Hib (n = 9), SP (n = 3) and Group B Streptococcus (n = 1). No etiologic cause was identified to explain the abnormal CSP pleocytosis and biochemistry in the remaining five cases. In contrast, the CSF analysis was normal in 42 other children with probable viral and non-infectious neurological condition, mostly febrile convulsions. The overall frequency rate for all types of meningitis and especially for Hib meningitis were 43 and 31 cases per 100 000 children < 5 years of age, respectively. These findings support our earlier observations that Hib meningitis still remains the leading cause of childhood meningitis in our region. Also it reaffirms the observation that bacterial meningitis may often be under-reported if CSF positive culture alone is considered for the diagnosis

Genetic and environmental factors associated with migraine in schoolchildren

Objective.-The aim of this study was to find the prevalence of migraine and headache in schoolchildren in the United Arab Emirates and to determine the genetic and environmental factors associated with these conditions