Connectivity of diagnostic technologies: improving surveillance and accelerating tuberculosis elimination

In regard to tuberculosis (TB) and other major global epidemics, the use of new diagnostic tests is increasing dramatically, including in resource-limited countries. Although there has never been as much digital information generated, this data source has not been exploited to its full potential. In this opinion paper, we discuss lessons learned from the global scale-up of these laboratory devices and the pathway to tapping the potential of laboratory-generated information in the field of TB by using connectivity. Responding to the demand for connectivity, innovative third-party players have proposed solutions that have been widely adopted by field users of the Xpert(®) MTB/RIF assay. The experience associated with the utilisation of these systems, which facilitate the monitoring of wide laboratory networks, stressed the need for a more global and comprehensive approach to diagnostic connectivity. In addition to facilitating the reporting of test results, the mobility of digital information allows the sharing of information generated in programme settings. When they become easily accessible, these data can be used to improve patient care, disease surveillance and drug discovery. They should therefore be considered as a public health good. We list several examples of concrete initiatives that should allow data sources to be combined to improve the understanding of the epidemic, support the operational response and, finally, accelerate TB elimination. With the many opportunities that the pooling of data associated with the TB epidemic can provide, pooling of this information at an international level has become an absolute priority.

Biochemical and molecular characteristics of Malaysian patients with lysinuric protein intolerance

Lysinuric protein intolerance (LPI) is an inborn error of dibasic amino acid transport due to a defect in the dibasic amino acid transporter in the renal and intestine and has a heterogenous presentation. Three Malaysian patients with LPI were studied and their biochemical and molecular findings compared. There were differences and similarities in the biochemical and molecular findings. Molecular analysis of SLC7A7 gene revealed a novel mutation c.235G>A; p.(Gly79Arg) in exon three in Patient 1 and a mutation c.1417C>T; p.(Arg473*) in exon 10 in patient 2 and 3. The degree of concentration of dibasic amino acids may determine the type of disease of the cell membrane transport, however, a positive molecular confirmation will secure the diagnosis.

Serum Fragments of Tau for the Differential Diagnosis of Alzheimer's Disease

Differential diagnosis of AD is still a challenge due to overlapping features with other types of dementia. Biomarkers for the differential diagnosis of AD can improve the diagnostic value of the disease and ensure an appropriate treatment of patients. The aim of this study was to evaluate the potential of two neo-epitope fragments of Tau as serum biomarkers for differential diagnosis of AD. The neo-epitope fragments of Tau were assessed in a cross-sectional cohort of subjects with AD, MCI, other dementias or subjects with non-dementia related memory complaints. The two Tau neo-epitope fragments were an ADAM10-generated fragment (Tau-A) and a caspase-3-generated fragment (Tau-C). The serum levels of the fragments were measured by two competitive ELISAs detecting Tau-A and Tau-C, respectively. Tau-A and Tau-C were able to separate subjects with AD and MCI from those with other dementias (p<0.0042 and p<0.05), and Tau-A could also discriminate between AD and MCI patients and subjects with non-dementia related memory complaints (p<0.05). Tau-A showed a significantly greater discrimination between AD and MCI subjects and patients with other dementias when compared to CSF biomarkers t-Tau and p-Tau. The ability of Tau-A to differentiate between AD and MCI from other dementias was comparable with CSF Aβ1-42, t-Tau/Aβ1-42 and p-Tau/Aβ1-42. The separation between the diagnostic groups was significantly improved when the CSF biomarkers as well as age and BMI were used in combination with Tau-A (AUC=0.87, 95% CI: 0.75-0.94) (p<0.0001). In conclusion, this study shows that a neoepitope fragment of Tau detected in serum can provide guidance on the differential diagnosis of AD.

Urban and rural comparison of vitamin D status in Pakistani pregnant women and neonates

We undertook a cross-sectional study in rural Jehlum and urban Karachi to evaluate the prevalence of vitamin D deficiency in Pakistani pregnant women and neonates and to assess any association of serum 25(OH) vitamin D [25(OH)D] concentration with vitamin D binding protein (Gc) genotypes. Altogether, 390 women and 266 neonates were recruited from urban and rural sites, respectively. Serum 25(OH)D was measured by an immunoassay, while Gc genotypes were identified using polymerase chain reaction followed by restriction fragment length polymorphism or PCR-RFLP. One-way analysis of variance or ANOVA and linear regression were used for statistical analysis. In urban Karachi, 99.5% of women and 97.3% of neonates were vitamin D deficient (< 50 nmol/L), while 89% of women and 82% of neonates were deficient in rural Jehlum. Gc genotypes were not associated with serum 25(OH)D concentrations in both women and their neonates. We conclude that vitamin D deficiency is highly prevalent in Pakistani women and their neonates, and Gc genotypes are not associated with serum 25(OH)D concentrations.

Comparative Study of Clinical and Sonographic Estimation of Foetal Weight at Term

A cross sectional comparative study was conducted at Dhaka National Medical College, Dhaka from January to June 2012, to observe the accuracy of clinical and ultrasonographic estimation of foetal weight at term in our environment. Seventy five pregnant women who fulfilled the inclusion criteria had their foetal weight estimated independently using clinical and ultrasonographic methods. Accuracy was determined by percentage error, absolute percentage error and proportion of estimates within 10% of actual birth weight (birth weight fetus of +10%). Statistical analysis was done using the paired t-test, the Wilcoxon signed-rank test, and the chi-square test. The study sample had an actual average birth weight of 2989.60 ± 408.76 (range 2310-4000 gm). Overall, the clinical method overestimated birth-weight, while ultrasound underestimated it. The mean absolute percentage error of the clinical method was more than that of the sonographic method, and the number of estimates within 10% of actual birth weight for the clinical method (41.3%) was less than for the sonographic method (57.3%); the difference was not statistically significant. In the low birth-weight (<2,500 gm) group, the mean absolute percentage error of sonographic estimates were significantly smaller. Significantly more sonographic estimates (75%) were within 10% of actual birth-weight than those of the clinical method (0%). No statistically significant difference was observed in all the measures of accuracy for the normal birth-weight range of 2,500-<4,000 gm and in the macrosomic group (≥ 4,000 gm). Clinical estimation of birth-weight is as accurate as routine ultrasonographic estimation, except in low-birth-weight babies.

Advanced 3D-Sonographic Imaging as a Precise Technique to Evaluate Tumor Volume

Determination of tumor volume in subcutaneously inoculated xenograft models is a standard procedure for clinical and preclinical evaluation of tumor response to treatment. Practitioners frequently use a hands-on caliper method in conjunction with a simplified formula to assess tumor volume. Non-invasive and more precise techniques as investigation by MR or (μ)CT exist but come with various adverse effects in terms of radiation, complex setup or elevated cost of investigations. Therefore, we propose an advanced three-dimensional sonographic imaging technique to determine small tumor volumes in xenografts with high precision and minimized observer variability. We present a study on xenograft carcinoma tumors from which volumes and shapes were calculated with the standard caliper method as well as with a clinically available three-dimensional ultrasound scanner and subsequent processing software. Statistical analysis reveals the suitability of this non-invasive approach for the purpose of a quick and precise calculation of tumor volume in small rodents.

T1 gadolinium enhancement of intracranial atherosclerotic plaques associated with symptomatic ischemic presentations

BACKGROUND AND PURPOSE

Contrast enhancement of intracranial atherosclerotic plaques has recently been investigated using high field and high resolution MR imaging as a risk factor in the development of ischemic stroke. We studied the reliability of conventional MR imaging at 1.5T in evaluating intraplaque enhancement and its relationship with acute cerebrovascular ischemic presentations in patients with severe intracranial atherosclerotic disease.

MATERIALS AND METHODS

We retrospectively identified and analyzed 19 patients with 22 high-grade intracranial atherosclerotic disease plaques (>70% stenosis) in vessels cross-sectionally visualized by neuroanatomic MR imaging. Atherosclerotic plaques were classified as asymptomatic or symptomatic. Two blinded neuroradiologists independently ranked each lesion for the presence of intraplaque enhancement by use of a 5-point scale (1-5). Furthermore, plaque enhancement was quantified as the relative change in T1WI spin-echo signal intensity (postcontrast/precontrast) in the vessel wall at the site of each intracranial atherosclerotic disease lesion.

RESULTS

Intraplaque enhancement was observed in 7 of 10 (70%) symptomatic plaques, in contrast to 1 of 12 (8%) asymptomatic plaques. Interobserver reliability correlated well for intraplaque enhancement (κ = 0.82). The degree of relative plaque enhancement in symptomatic versus asymptomatic lesions (63% versus 23%) was statistically significant (P = .001, t test).

CONCLUSIONS

In this pilot study, we determined that intraplaque enhancement could be reliably evaluated with the use of cross-sectional imaging and analysis of vessels/plaques by use of conventional neuroanatomic MR imaging protocols. In addition, we observed a strong association between intraplaque enhancement in severe intracranial atherosclerotic disease lesions and ischemic events with the use of conventional MR imaging. Our preliminary study suggests that T1 gadolinium-enhancing plaques may be an indicator of progressing or symptomatic intracranial atherosclerotic disease.

Pregnancy outcome in a case of non-obstructive hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is a relatively common genetic disorder (1:500) inherited as an autosomal dominant trait. It is caused by mutations in any one of 10 genes encoding protein components of cardiac sarcomere. Some theoretically calculated risks exist when patients with HCM become pregnant. The physiologic increase of cardiac output and increased stroke volume may be impaired due to the non-compliant ventricular walls. In the first trimester, the physiologic hypervolemia of pregnancy to some extent counteracts the natural decrease in peripheral vascular resistance which would have otherwise provoked an obstruction gradientin systolic flow. As pregnancy advances, the vena caval compression may decrease venous return causing cardiac compromise, whereas the stress of labour may precipitate arrhythmia. We report our experience of a pregnancy with co-existant non-obstructive hypertrophic cardiomyopathy and nodal bradycardia ultimately resulting in pre-term delivery, neonatal death and maternal death in puerperium from overt cardiac failure after a relatively uneventful gestation.

Successful pregnancy outcome with coexisting primary epithelial ovarian carcinoma

Maternal epithelial ovarian cancer (EOC) is rare. EOC is reported to occur in 1:12,000 to 1:50,000 pregnancies. We report a case of Stage IA epithelial ovarian cancer detected in the first trimester managed by laparotomy at 13 weeks followed by left sided salpingo-oophorectomy and infra-colic omentectomy. Histopathology revealed papillary mucinous cystadenocarcinoma (well differentiated with negative peritoneal cytology for malignancy). Chemotherapy was not warranted due to early stage disease and she had an uneventful gestation ending in vaginal delivery of a 2.5 kilogram male baby at term. During the period of follow up she developed no clinical or biochemical evidence of tumour recurrence or relapse.

Mechanical characterization of sintered piezo-electric ceramic material using scanning acoustic microscope

Lead Zirconate Titanate (PZT) is a piezo-electric ceramic material that needs to be characterized for its potential use in microelectronics. Energy dispersive X-ray analysis (EDX) is conducted to determine the chemical composition of the PZT ceramics. The scanning electron microscope (SEM) is performed to study the surface morphology, grain structure and grain boundaries. The SEM image helps us to understand the surface wave propagation and scattering phenomena by the PZT and the reason for its anisotropy and inhomogeneity due to the grain structure. In this paper scanning acoustic microscopy at 100 MHz excitation frequency is conducted for determining mechanical properties of PZT. Earlier works reported only the longitudinal wave speed in PZT while in this paper longitudinal, shear and surface acoustic wave speeds of sintered PZT are measured from its acoustic material signature (AMS) curves, also known as V(z) curves. AMS or V(z) curve is the variation of the output voltage as a function of the distance between the acoustic lens focal point and the reflecting surface. The average velocities of longitudinal, shear and surface acoustic waves in a PZT specimen are determined from its V(z) curve generated at 100 MHz excitation frequency and found to be over 5000 m/s, over 3000 m/s and between 2500 and 3000 m/s, respectively. From these velocities all elastic constants of the specimen are obtained.