A human in vitro model system for investigating genome-wide host responses to SARS coronavirus infection

Background

Schistosoma mansoni and Plasmodium falciparum are common infections of school aged children in Kenya. They both cause enlargement of the spleen, but their relative contribution to the condition of splenomegaly remains unknown in areas where both infections are endemic. Here, we have investigated whether relatively high exposure to both infections has a clinically measurable effect on this condition.

Methods

96 children aged 6–16 years living along a ten kilometre stretch and within 4 km south of a river that is a source of both S. mansoni and malaria infections were examined clinically for splenomegaly along the mid clavicular line (MCL) and mid axillary line (MAL). The survey was conducted outside the malaria transmission season. The consistency of the organ was recorded as soft, firm or hard. Mapping of the locations of houses and the course of the river was undertaken. Egg counts were mapped at the household level, as were IgG3 responses to Plasmodium falciparum schizont antigen (anti-Pfs IgG3), in order to identify areas with relatively high exposure to both infections, either infection or neither infection. ANOVA was used to test for differences in egg counts, IgG3 levels and the magnitude of spleen enlargement between these areas.

Results

4 contiguous sectors were identified, one where anti-Pfs IgG3 responses and S. mansoni egg counts were both high, one where only anti-Pfs IgG3 responses were high, one where only egg counts were high, and one where both anti-Pfs IgG3 responses and egg counts were low. Spleen MAL and MCL values were significantly higher amongst children from the sector with highest IgG3 levels and highest egg counts but similar amongst children from elsewhere. Both egg counts and anti-Pfs IgG3 responses were significantly higher in children with MAL values >=4 cm. Hardening of spleens was associated with proximity of domicile to the river.

Conclusions

Micro-geographical variation in exposure to S. mansoni and malaria infections can be exploited to investigate the chronic impact of these two infections. These results provide firm evidence that relatively high exposure to both infections exacerbates splenomegaly even outside the malaria transmission season. Major implications include assessing the burden of infection in school age-children.     

Serum hepatitis B surface antigen correlates with fibrosis and necroinflammation: A multicentre perspective in China

The kinetics of serum hepatitis B surface antigen (HBsAg) during the natural history of hepatitis B virus (HBV) infection has been studied, but the factors affecting them remain unclear. We aimed to investigate the factors affecting HBsAg titres, using data from multicentre, large‐sized clinical trials in China. The baseline data of 1795 patients in 3 multicentre trials were studied, and the patients were classified into 3 groups: hepatitis B early antigen (HBeAg)‐positive chronic HBV infection (n = 588), HBeAg‐positive chronic hepatitis B (n = 596), and HBeAg‐negative chronic hepatitis B (n = 611). HBsAg titres in the different phases were compared, and multiple linear progression analyses were performed to investigate the implicated factors. HBsAg titres varied significantly in different phases (P = .000), with the highest (4.60 log10 IU/mL [10%‐90% confidence interval: 3.52 log10 IU/mL‐4.99 log10 IU/mL]) in patients with HBeAg‐positive chronic HBV infection. In all phases, age and HBV DNA were correlated with serum HBsAg level. In HBeAg‐positive chronic hepatitis B patients, a negative correlation between HBsAg titres and fibrosis stage was observed. Alanine amonitransferase or necroinflammatory activity was also correlated with HBsAg titres in HBeAg‐negative chronic hepatitis B patients. In conclusion, decreased HBsAg titres may be associated with advancing fibrosis in HBeAg‐positive chronic hepatitis B patients or increased necroinflammation in those with HBeAg‐negative chronic hepatitis B. Our findings may help clinicians better understand the kinetics of HBsAg and provide useful insights into the management of this disease.     

Mutational scanning of large genes by extensive PCR multiplexing and two-dimensional electrophoresis: application to the RB1 gene

With the rapid increase in the number of identified human disease genes, the development of accurate and cost-efficient mutation tests has become opportune. Here we present a combination of extensive PCR multiplexing and two-dimensional (2-D) DNA electrophoresis to screen for mutations in 26 exons of the retinoblastoma (RB1) tumor suppressor gene. In 2-D electrophoresis, fragments are separated according to size and base pair sequence in non-denaturing and denaturing gradient gels, respectively. All target fragments, designed to have optimal melting characteristics, were prepared in a two-step PCR (a 6-plex long-PCR pre- amplification and a subsequent 25-plex short-PCR) followed by heteroduplexing. The mixture of PCR amplicons was then subjected to 2-D electrophoresis under a single set of experimental conditions. With this design, 35 previously identified mutations in 18 different exons were detected in 33 bilateral retinoblastoma patients. These results suggest that 2-D electrophoresis in this format provides a generally applicable, practical and fast way to diagnose with high accuracy large genes for a broad spectrum of possible disease-causing mutations.      

Relationship between image quality and ultrasound exposure level in diagnostic US devices

Ultrasonographic B-mode images were obtained at various exposure levels with three real-time diagnostic scanners. Adult human and tissue-equivalent phantom images were compared in terms of diagnostic content and depth of penetration. For the exposure level settings used, spatial-peak pulse-average intensities ranged from approximately 10 to 500 W/cm2. At the 3.50-3.75-MHz nominal frequencies used in the study, images of the human abdomen showed little discernible change in quality with varying exposure levels. However, phantom tests confirmed that depth of penetration is a function of exposure level. The results suggest that a judicious use of exposure level and receiver gain controls can be a practical means for minimizing patient exposure to ultrasound without sacrifice of diagnostic effectiveness.     

UK childbirth delivery options in 2001–2002: alternatives to consultant unit booking and delivery

BACKGROUND: Government policy advocates maternal choice in pregnancy care. Two key issues are place of birth and type of lead professional. Anecdotal evidence suggests there is variation in both these issues across the UK, but there has been no recent national assessment of whether maternal options are in line with government policy. AIM: To establish the range of women's childbirth delivery options, degree of midwife autonomy, and supporting training and governance mechanisms. DESIGN: Two postal questionnaires. SETTING: UK maternity units. METHOD: Questionnaires were sent to maternity services managers. MAIN OUTCOME MEASURES: number and type of units and births, transfers and care types; midwifery procedures; clinical governance and training activities. RESULTS: Completed questionnaires were received from 301 out of 308 (97.7%) units in 2002 and from 258 out of 309 (83.5%) units in 2001. Midwife-led care is available in 186 English (76.9%), 15 Welsh (78.9%), 18 Scottish (48.6%) and three Northern Ireland (30.0%) units. There are 73 (24.3%) stand-alone, 22 (7.3%) alongside, 127 (42.2%) integrated and 79 (26.2%) consultant units (for definitions of unit types, see main text), with a median 2215 hospital, 25 home and 210 midwife-led births. The median antenatal and labour transfers from midwife-led units are 25.5% (interquartile range [IQR] = 18.5-36.5%) and 18.0% (IQR = 13.4-24.8%) respectively; transfers are independent of distance to nearest consultant unit, country and unit type. CONCLUSIONS: Despite government policy promoting greater parental choice, this is not in evidence in many parts of the UK. The wide variations in home birth, midwife-led care and maternity-unit types merit further exploration. If more midwife-led units are to be established as a way of promoting parental choice and dealing with junior doctor rota problems, then such units must have adequate governance and training activities in place.     

Epstein-Barr virus-associated hemophagocytic syndrome: virological and immunopathological studies

The virus-associated hemophagocytic syndrome (VAHS) is a disorder characterized by a benign, generalized histiocytic proliferation, with marked hemophagocytosis associated with systemic viral infections. We have studied the virological and immunopathological events occurring in two children experiencing Epstein-Barr VAHS. Neither of the patients had an underlying immunodeficiency and both recovered from their disease and are completely well one year after follow-up. In each patient, evidence for primary Epstein-Barr virus (EBV) infection was documented with a typical humoral immune response, including IgM antibody directed against virus capsid antigen. EBV was demonstrated in lymphoreticular tissues by electron microscopy and molecular hybridization studies. Permissive EBV infection was suggested by the finding of mature virus particles and linear viral DNA in lymphoreticular tissues. Immunopathological studies demonstrated complete effacement of lymph node architecture by a marked proliferation of immunoblasts in patient 1 and infiltration and effacement of the lymph node architecture with benign-appearing histiocytes in patient 2. Atypical lymphocytes characteristic of acute EBV infection were notably absent in the peripheral blood of both patients and cytotoxic T cells, which normally lyse EBV-infected B cells, were also absent from the peripheral circulation. Our observations suggest that EBV-induced VAHS may be the result of an increased virus burden in the face of immunoregulatory cell imbalances.     

The esophagus after endoscopic injection sclerotherapy: acute and chronic changes

The changes seen on radiographs of the esophagus following endoscopic injection sclerotherapy (EIS) for varices are described and illustrated. In the early period (within 30 days) after EIS, the spectrum of changes includes mucosal ulceration, luminal narrowing, intramural defects, sinuses, fistulae, esophageal dissection, and perforation. In the late period (after 30 days), the spectrum includes strictures, irregular contour, mural defects, esophageal dysmotility, and luminal obstruction. Familiarity with these radiographic features will aid in proper interpretation of esophagograms following EIS for esophageal varices.