Antenatal screening and prevalence of infection: surveillance in London, 2000-2007

In the United Kingdom (UK), it is recommended to universally offer antenatal infection screening for human immunodeficiency virus (HIV), hepatitis B and syphilis infections, and susceptibility to rubella for the benefit of the mother and to reduce vertical transmission of infection. This paper describes the surveillance of antenatal infection including uptake of screening, and the results of testing in pregnant women in London between 2000 and 2007. Antenatal screening coordinators in liaison with midwifery heads and microbiologists at all thirty London National Health Service (NHS) Trust maternity units supplied quarterly data on the number of pregnant women booked for antenatal care, tests done, and tests results. The overall estimated uptake of screening increased since 2000 and reached 95.6% for HIV, 96.5% for syphilis, 96.2% for hepatitis B and 97% for rubella susceptibility by the second half of 2007. There is considerable variation in the performance between NHS Trusts. The overall estimated prevalence of HIV infection was 3.4/1,000 women (ranging from <1/1,000 to 10/1,000 across Trusts), of hepatitis B (HBsAg-positive) was 11.3/1,000 (2.6/1,000- 23.9/1,000), of syphilis was 4.4/1,000 (<1/1,000-16.3/1,000) and of rubella susceptibility was 39.3/1,000 (19-103/1,000). Antenatal infection screening has improved and there has been some success in implementation of national policy. However, screening uptake and prevalence of infection vary considerably across London NHS Trusts and some women are evidently disadvantaged. Improvements in information systems should help local partners to focus their interventions in those Trusts where work is still needed to increase testing as well as the capacity to monitor the uptake of screening.

Antenatal screening and prevalence of infection: surveillance in London, 2000-2007

In the United Kingdom (UK), it is recommended to universally offer antenatal infection screening for human immunodeficiency virus (HIV), hepatitis B and syphilis infections, and susceptibility to rubella for the benefit of the mother and to reduce vertical transmission of infection. This paper describes the surveillance of antenatal infection including uptake of screening, and the results of testing in pregnant women in London between 2000 and 2007. Antenatal screening coordinators in liaison with midwifery heads and microbiologists at all thirty London National Health Service (NHS) Trust maternity units supplied quarterly data on the number of pregnant women booked for antenatal care, tests done, and tests results. The overall estimated uptake of screening increased since 2000 and reached 95.6% for HIV, 96.5% for syphilis, 96.2% for hepatitis B and 97% for rubella susceptibility by the second half of 2007. There is considerable variation in the performance between NHS Trusts. The overall estimated prevalence of HIV infection was 3.4/1,000 women (ranging from <1/1,000 to 10/1,000 across Trusts), of hepatitis B (HBsAg-positive) was 11.3/1,000 (2.6/1,000- 23.9/1,000), of syphilis was 4.4/1,000 (<1/1,000-16.3/1,000) and of rubella susceptibility was 39.3/1,000 (19-103/1,000). Antenatal infection screening has improved and there has been some success in implementation of national policy. However, screening uptake and prevalence of infection vary considerably across London NHS Trusts and some women are evidently disadvantaged. Improvements in information systems should help local partners to focus their interventions in those Trusts where work is still needed to increase testing as well as the capacity to monitor the uptake of screening.

Inherited predisposition to colorectal adenomas caused by multiple rare alleles of MUTYH but not OGG1, NUDT1, NTH1 or NEIL 1, 2 or 3

BACKGROUND

MUTYH-associated polyposis (MAP) is a recessive trait characterised by multiple colorectal adenomas and a high risk of colorectal cancer. MUTYH functions in the DNA base excision repair pathway and has a key role in the repair of oxidative DNA damage.

OBJECTIVES

To assess the contribution of inherited variants in genes involved in base excision repair and oxidative DNA damage including MUTYH, OGG1, NEIL1, NEIL2, NEIL3, NUDT1 and NTH1 to the multiple colorectal adenoma phenotype.

METHODS

Inherited variants of MUTYH, OGG1, NEIL1, NEIL2, NEIL3, NUDT1 and NTH1 were sought in 167 unrelated patients with multiple colorectal adenomas whose family histories were consistent with recessive inheritance. These variants were also characterised in approximately 300 population controls.

RESULTS

Thirty-three patients (20%) and no controls were MUTYH homozygotes or compound heterozygotes (ie, carried two mutations) and therefore had MAP. Eight different pathogenic MUTYH mutations were identified, of which four were novel. MAP cases had significantly more adenomas than non-MAP cases (p = 0.0009; exact test for trends in proportions) and presented earlier (p = 0.013; analysis of variance). Twenty-four protein-altering variants were identified upon screening of OGG1, NEIL1, NEIL2, NEIL3, NUDT1 and NTH1. However, all combinations of two (or more) variants that were identified at an individual locus in patients were also seen in controls, and no variants were significantly over-represented (or under-represented) in cases.

CONCLUSION

Multiple rare alleles of MUTYH are associated with autosomal recessive MAP, while OGG1, NEIL1, NEIL2, NEIL3, NUDT1 and NTH1 do not contribute significantly to autosomal recessive polyposis.

Likelihood of a particular order of genetic markers and the construction of genetic maps

We model the recombination process of fungal systems via chromatid exchange in meiosis, which accounts for any type of bivalent configuration in a genetic interval in any specified order of genetic markers, for both random spore and tetrad data. First, a probability model framework is developed for two genes and then generalized for an arbitrary number of genes. Maximum likelihood estimators (MLEs) for both random and tetrad data are developed. It is shown that the MLE of recombination for tetrad data is uniformly more efficient over that from random spore data by a factor of at least 4 usually. The MLE for the generalized probability framework is computed using the expectation-maximization (EM) algorithm. Pearson's chi-squared statistic is computed as a measure of goodness of fit using a product-multinomial setup. We implement our model with genetic marker data on the whole genome of Neurospora crassa. Simulated annealing is used to search for the best order of genetic markers for each chromosome, and the goodness of fit value is evaluated for model assumptions. Inferred map orders are corroborated by genomic sequence, with the exception of linkage groups I, II, and V.

Cultural enhancement of a clinical service to meet the needs of indigenous people; genetic service development in response to issues for New Zealand Maori

The delivery of good health care services within clinical settings is predicated by an understanding of the needs of the stakeholders. Most of the information generated to date on the transfer of mutational analysis to clinical service has been within a Eurocentric model favouring individual autonomy. It is predictable that this model does not easily translate for other cultures. Current genetic technology has elucidated the molecular basis of many diseases. In familial cancer and other late-onset disorders, there is now the possibility of 'prediction' where a high risk conferred by family history can be confirmed or negated by genetic testing. In paediatric disorders, prediction is offered in the form of prenatal or pre-implantation genetic diagnosis. We report on the processes undertaken in an attempt to provide a culturally sensitive service for the Maori people of Aotearoa, New Zealand.

Systems biology of the neurospora biological clock

A major challenge of systems biology is explaining complex traits, such as the biological clock, in terms of the kinetics of macromolecules. The clock poses at least four challenges for systems biology: (i) identifying the genetic network to explain the clock mechanism quantitatively; (ii) specifying the clock's functional connection to a thousand or more genes and their products in the genome; (iii) explaining the clock's response to light and other environmental cues; and (iv) explaining how the clock's genetic network evolves. Here, the authors illustrate an approach to these problems by fitting an ensemble of genetic networks to microarray data derived from oligonucleotide arrays with approximately all 11 000 Neurospora crassa genes represented. A promising genetic network for the clock mechanism is identified.

The role of interleukin 6 in megakaryocyte formation, megakaryocyte development and platelet production

Megakaryocytopoiesis is the cellular amplification and differentiation of precursors into immature megakaryocytes, and the cytoplasmic maturation of these megakaryocytes, a process terminating in the release of platelets into the circulation. Interleukin 6 (IL-6) stimulates megakaryocytopoiesis in the bone marrow, increasing platelet numbers in the circulation. IL-6 alone is poorly active on the growth of stem cell populations, but acts in synergy with stem cell factor (c-kit ligand) to expand the committed myeloid progenitor compartments but not the megakaryocyte progenitors. IL-6 has a direct action on megakaryocyte progenitors but only in synergy with low doses of interleukin 3 (IL-3), increasing the number of immature megakaryocytes and enhancing the processes of development into mature megakaryocytes. IL-6 is about 10 times more active on megakaryocytes than on megakaryocyte progenitors in cell culture. It is active alone and will stimulate increases in cell size and DNA content. IL-6 does not appear to stimulate the process of platelet release. IL-6 is found in bone marrow, in both macrophage subsets and megakaryocytes, indicating that it may be an important physiological regulator of both paracrinal (microenvironmental) and autocrinal mechanisms controlling megakaryocyte development in bone marrow.

Design and analysis of an efficient recursive linking algorithm for constructing likelihood based genetic maps for a large number of markers

A multi-locus likelihood of a genetic map is computed based on a mathematical model of chromatid exchange in meiosis that accounts for any type of bivalent configuration in a genetic interval in any specified order of genetic markers. The computational problem is to calculate the likelihood (L) and maximize L by choosing an ordering of genetic markers on the map and the recombination distances between markers. This maximum likelihood estimate (MLE) could be found either with a straightforward algorithm or with the proposed recursive linking algorithm that implements the likelihood computation process involving an iterative procedure is called Expectation Maximization (EM). The time complexity of the straightforward algorithm is exponential without bound in the number of genetic markers, and implementation of the model with a straightforward algorithm for more than seven genetic markers is not feasible, thus motivating the critical importance of the proposed recursive linking algorithm. The recursive linking algorithm decomposes the pool of genetic markers into segments and renders the model implementable for hundreds of genetic markers. The recursive algorithm is shown to reduce the order of time complexity from exponential to linear in the number of markers. The improvement in time complexity is shown theoretically by a worst-case analysis of the algorithm and supported by run time results using data on linkage group-II of the fungal genome Neurospora crassa.

Succinylcholine or rocuronium? A meta-analysis of the effects on intubation conditions

This meta-analysis was undertaken to compare the effects of succinylcholine (SCH) and rocuronium (RCR) on endotracheal intubation (ETI) conditions. Eligible randomised controlled trials (RCTs) were identified via medline and a manual search of references. The frequencies of excellent and unacceptable ETI conditions in subjects receiving SCH 1.0-1.5 mg/kg and RCR 0.6-1.2 mg/kg were determined using standard statistical methods. Inclusion criteria were met by 16 RCTs, representing 1362 subjects. SCH was associated with a 17.7% increase (95% CI = 13-22) in the frequency of excellent ETI conditions and a 5.1% decrease (95% CI = -7.3 to -2.9) in the frequency of unacceptable ETI conditions, when compared with RCR. In the subgroup undergoing true rapid sequence intubation, SCH was associated with a 19.1% increase (95% CI = 13.7-24.5) in the frequency of excellent ETI conditions. SCH appears to be superior to RCR in creating excellent ETI conditions and avoiding unacceptable ETI conditions.

Development of atrophy of the retinal pigment epithelium around disciform scars

BACKGROUND/AIMS

Eyes with burnt out disciform scars secondary to age related macular degeneration (AMD) are regarded as visually stable. The aim of this study is to report the subsequent development of atrophy of the retinal pigment epithelium (RPE) around the scars and discuss the possible basis.

METHODS

20 eyes from 18 patients were observed to develop atrophy around choroidal neovascularisation (CNV). A method of measuring expansion of the atrophy over time is described using the Topcon Imagenet 2000 system. An additional 10 clinicopathological examples were reviewed.

RESULTS

Clinically CNV became surrounded initially by a ring of pallor that progressed to an expanding band of atrophy of the RPE. It developed most rapidly in the first 3 years after CNV became quiescent but then continued to expand slowly to more than three times the size of the scar. Histopathological specimens showed large choroidal vessels entering the scars directly and a reduced number of small choroidal vessels beneath and around the scar

CONCLUSIONS

Disciform scars may become surrounded by an expanding band of atrophy of the RPE, postulated to result from remodelling of the choroidal circulation. The ongoing enlargement of the resulting scotoma may need to be considered when planning management and assessing treatment outcomes.

Efficient recursive linking algorithm for computing the likelihood of an order of a large number of genetic markers

Assuming no interference, a multi-locus genetic likelihood is implemented based on a mathematical model of the recombination process in meiosis that accounts for events up to double crossovers in the genetic interval for any specified order of genetic markers. The mathematical model is realized with a straightforward algorithm that implements the likelihood computation process. The time complexity of the straightforward algorithm is exponential without bound in the number of genetic markers and implementation of the model for more than 7 genetic markers is not feasible, motivating the need for a novel algorithm. A recursive linking algorithm is proposed that decomposes the pool of genetic markers into segments and renders the model implementable for a large number of genetic markers. The recursive algorithm is shown to reduce the order of time complexity from exponential to linear. The improvement in time complexity is shown theoretically by a worst-case analysis of the algorithm and supported by run time results using data on linkage group-I of the fungal genome Neurospora crassa.

Metabolic Model of Autoregulation in the Circle of Willis

The Circle of Willis (CoW) is a ringlike structure of blood vessels found at the base of the brain. Its main function is to distribute oxygen-rich arterial blood to the cerebral mass. In a previous study, a one-dimensional (1D) model of the CoW was created to simulate a series of possible clinical scenarios such as occlusions in afferent arteries, absent or stringlike circulus vessels, or arterial infarctions (Moorhead et al., 2004, Comput. Methods Biomech. Biomed. Eng., 7(3), pp. 121–130). The model captured cerebral haemodynamic autoregulation by using a proportional-integral-derivative (PID) controller to modify efferent artery resistances. Although some good results and correlations were achieved, the model was too simple to capture all the transient dynamics of autoregulation. Hence a more physiologically accurate model has been created that additionally includes the oxygen dynamics that drive the autoregulatory response. Results very closely match accepted physiological response and limited clinical data. In addition, a set of boundary conditions and geometry is presented for which the autoregulated system cannot provide sufficient perfusion, representing a condition with increased risk of stroke and highlighting the importance of modeling the haemodynamics of the CoW. The system model created is computationally simple so it can be used to identify at-risk cerebral arterial geometries and conditions prior to surgery or other clinical procedures.

Enhanced optical chromatography in a PDMS microfluidic system

The purely refractive index driven separation of uniformly sized polystyrene, n = 1.59 and poly(methylmethacrylate), n = 1.49 in an optical chromatography system has been enhanced through the incorporation of a custom poly(dimethysiloxane) (PDMS) microfluidic system. A customized channel geometry was used to create separate regions with different linear flow velocities tailored to the specific application. These separate flow regions were then used to expose the entities in the separation to different linear flow velocities thus enhancing their separation relative to the same separation in a constant velocity flow environment. A microbiological sample containing spores of the biological warfare agent, Bacillus anthracis, and a common environmental interferent, mulberry pollen, was investigated to test the use of tailored velocity regions. These very different samples were analyzed simultaneously only through the use of tailored velocity regions.

HspE7 treatment of pediatric recurrent respiratory papillomatosis: final results of an open-label trial

OBJECTIVES

We sought to evaluate the effectiveness of HspE7, a recombinant fusion protein of Hsp65 from Mycobacterium bovis BCG and E7 protein from human papillomavirus 16, to improve the clinical course of pediatric patients with recurrent respiratory papillomatosis.

METHODS

An open-label, single-arm intervention study was conducted in 8 university-affiliated medical centers. Twenty-seven male and female patients with recurrent respiratory papillomatosis, ages 2 to 18 years, were enrolled and followed up to 60 weeks. Before enrollment, these patients required surgery on average every 55 days. After a baseline debulking surgery, the patients received HspE7 500 microg subcutaneously monthly, for 3 doses over 60 days. The primary end point was the length of the interval from the last surgery during the treatment period until the first debulking surgery in the posttreatment period, compared with the median intersurgical interval (ISI) of the 4 surgeries before the treatment.

RESULTS

The mean of the first posttreatment ISI increased 93% (from 55 days to 106 days; p < .02). The median ISI for all surgeries after treatment was similarly prolonged (mean, 107 days; p < .02), indicating a sustained treatment effect, and was associated with a significant decrease in the number of required surgeries (p < .003). Unexpectedly, the treatment effect was most striking in the 13 female patients, who had statistically significant increases in both the first posttreatment ISI (142%; p < .03) and the median ISI (147%; p < .03). The most common adverse events were mild-to-moderate injection site reactions.

CONCLUSIONS

Treatment with HspE7 appears to significantly improve the clinical course in pediatric patients with RRP insofar as it reduces the frequency of required surgeries. These results warrant a confirmatory phase III trial.

Rationing in the emergency department: the good, the bad, and the unacceptable

OBJECTIVES

Waiting times in emergency departments (EDs) are an important government priority. Although substantial efforts are currently being made to reduce waiting times, little attention has been paid to the patients' view. We used qualitative methods to explore patients' perspectives on waiting times and other approaches to rationing and prioritisation.

METHODS

Face to face, in depth, qualitative interviews (n = 11) explored how patients valued waiting times for non-urgent ED care. The framework approach (identifying a thematic framework through repeated re-reading) was used to analyse transcripts.

RESULTS

Interviewees found some forms of rationing and prioritisation acceptable. They expected rationing by delay, but required explanations or information on the reason for their wait. They valued prioritisation by triage (rationing by selection) and thought that this role could be expanded for the re-direction of non-urgent patients elsewhere (rationing by deflection). Interviewees were mainly unwilling or unable to engage in prioritisation of different types of patients, openly prioritising only those with obvious clinical need, and children. However, some interviewees were willing to ration implicitly, labelling some attenders as inappropriate, such as those causing a nuisance. Others felt it was unacceptable to blame "inappropriate" attenders, as their attendance may relate to lack of information or awareness of service use. Explicit rationing between services was not acceptable, although some believed there were more important priorities for NHS resources than ED waiting times. Interviewees disagreed with the hypothetical notion of paying to be seen more quickly in the ED (rationing by charging).

CONCLUSIONS

Interviewees expected to wait and accepted the need for prioritisation, although they were reluctant to engage in judgements regarding prioritisation. They supported the re-direction of patients with certain non-urgent complaints. However, they perceived a need for more explanation and information about their wait, the system, and alternative services.

3D models of blood flow in the cerebral vasculature

The circle of Willis (CoW) is a ring-like arterial structure located in the base of the brain and is responsible for the distribution of oxygenated blood throughout the cerebral mass. To investigate the effects of the complex 3D geometry and anatomical variability of the CoW on the cerebral hemodynamics, a technique for generating physiologically accurate models of the CoW has been created using a combination of magnetic resonance data and computer-aided design software. A mathematical model of the body's cerebral autoregulation mechanism has been developed and numerous computational fluid dynamics simulations performed to model the hemodynamics in response to changes in afferent blood pressure. Three pathological conditions were explored, namely a complete CoW, a fetal P1 and a missing A1. The methodology of the cerebral hemodynamic modelling is proposed with the potential for future clinical application in mind, as a diagnostic tool.

Tissue engineering of autologous cartilage grafts in three-dimensional in vitro macroaggregate culture system

In the field of tissue engineering, techniques have been described to generate cartilage tissue with isolated chondrocytes and bioresorbable or nonbioresorbable biomaterials serving as three-dimensional cell carriers. In spite of successful cartilage engineering, problems of uneven degradation of biomaterial, and unforeseeable cell-biomaterial interactions remain. This study represents a novel technique to engineer cartilage by an in vitro macroaggregate culture system without the use of biomaterials. Human nasoseptal or auricular chondrocytes were enzymatically isolated and amplified in conventional monolayer culture before the cells were seeded into a cell culture insert with a track-etched membrane and cultured in vitro for 3 weeks. The new cartilage formed within the in vitro macroaggregates was analyzed by histology (toluidine blue, von Kossa-safranin O staining), and immunohistochemistry (collagen types I, II, V, VI, and X and elastin). The total glycosaminoglycan (GAG) content of native and engineered auricular as well as nasal cartilage was assayed colorimetrically in a safranin O assay. The biomechanical properties of engineered cartilage were determined by biphasic indentation assay. After 3 weeks of in vitro culture, nasoseptal and auricular chondrocytes synthesized new cartilage with the typical appearance of hyaline nasal cartilage and elastic auricular cartilage. Immunohistochemical staining of cartilage samples showed a characteristic pattern of staining for collagen antibodies that varied in location and intensity. In all samples, intense staining for cartilage-specific collagen types I, II, and X was observed. By the use of von Kossa-safranin O staining a few positive patches-a possible sign of beginning mineralization within the engineered cartilages-were detected. The unique pattern for nasoseptal cartilage is intense staining for type V collagen, whereas auricular cartilage is only weakly positive for collagen types V and VI. Engineered nasal and auricular macroaggregates were negative for anti-elastin antibody (interterritorially). The measurement of total GAG content demonstrated higher GAG content for reformed nasoseptal cartilage compared with elastic auricular cartilage. However, the total GAG content of engineered macroaggregates was lower than that of native cartilage. In spite of the mechanical stability of the auricular macroaggregates, there was no equilibrium of indentation. The histomorphological and immunohistochemical results demonstrate successful cartilage engineering without the use of biomaterials, and identify characteristics unique to hyaline as well as elastic cartilage. The GAG content of engineered cartilage was lower than in native cartilage and the biomechanical properties were not determinable by indentation assay. This study illustrates a novel in vitro macroaggregate culture system as a promising technique for tissue engineering of cartilage grafts. Further long-term in vitro and in vivo studies must be done before this method can be applied to reconstructive surgery of the nose or auricle.