Worldwide proficiency test for routine analysis of δ2H and δ18O in water by isotope-ratio mass spectrometry and laser absorption spectroscopy

RATIONALE

The interpretation of stable hydrogen and oxygen isotope data in isotope hydrology relies on accurate, high-precision analytical measurements of the (2)H:(1)H and (18)O:(16)O ratios in liquid H(2)O samples.

METHODS

A synthesis of the International Atomic Energy Agency (IAEA) worldwide proficiency test for analytical laboratories conducting routine analysis of δ(2)H and δ(18)O values in water (WICO2011) by isotope-ratio mass spectrometry (IRMS) and laser absorption spectroscopy (LAS) technology has been carried out.

RESULTS

This test revealed that >96% of the 160 laboratory submissions provided acceptable results within ±2‰ for δ(2) H values and ±0.2‰ for δ(18)O values of the established reference values for four test waters, and no difference in outcomes based on IRMS vs. LAS technology was found for good performing laboratories.

CONCLUSIONS

The leading cause of outliers appeared to be improper calibration or compromised storage of laboratory standard and primary reference waters; hence the importance of judicious storage of lab standards cannot be understated. The deprecated practice of single standard normalization was identified as a problem for some laboratories. We further recommend that laboratories strive to report parsimonious long-term precisions based upon control standards, and to improve quantification and correction for LAS instrumental drift and inter-sample carryover effects.

Particulate matter characterization by gray level co-occurrence matrix based support vector machines

An efficient and highly reliable automatic selection of optimal segmentation algorithm for characterizing particulate matter is presented in this paper. Support vector machines (SVMs) are used as a new self-regulating classifier trained by gray level co-occurrence matrix (GLCM) of the image. This matrix is calculated at various angles and the texture features are evaluated for classifying the images. Results show that the performance of GLCM-based SVMs is drastically improved over the previous histogram-based SVMs. Our proposed GLCM-based approach of training SVM predicts a robust and more accurate segmentation algorithm than the standard histogram technique, as additional information based on the spatial relationship between pixels is incorporated for image classification. Further, the GLCM-based SVM classifiers were more accurate and required less training data when compared to the artificial neural network (ANN) classifiers.

Post-traumatic endophthalmitis with retained intraocular foreign body - a case report with review of literature

INTRODUCTION

Endophthalmitis following penetrating eye injuries has a poor prognosis and presents a diagnostic and therapeutic challenge. The aim of reporting this case was to identify the causative organism of post-traumatic endophthalmitis due to retained iron foreign body and to highlight the importance of carrying out diagnostic investigations.

CASE

A 20-year-old male presented with tenderness and blurring in the right eye 3 days after injury with an iron particle. Visual acuity was perception of light with accurate projection of rays in all quadrants. The slit-lamp examination revealed ciliary and conjuctival congestion. There was a vertically-oriented self-sealed, full-thickness laceration in the cornea adjacent to the limbus. The anterior chamber evaluation revealed + 4 cells, +3 flare and a 2 - mm hypopyon. There was cataract with a ruptured anterior lens capsule. Posterior synechae was present at 5�0 clock position. B-scan showed echogenic metallic foreign body in the posterior chamber, with vitreous opacities. The vitreous tap was done and intra-vitreal antibiotics injections of 1 mg in 0.1 ml vancomycin and 2.25 mg in 0.1 ml ceftazidime were given. Culture and sensitivity of the tap revealed staphylococcus as the causative agent. The patient was put on moxifloxacin eye drops, fortified tobramycin and cephazolin eye drops 1 hourly along with atropine eye drops. The patient was referred to the vitreoretinal surgeon urgently for pars plana vitrectomy and foreign body removal. At follow up, the patient's BCVA was improved.

CONCLUSION

The causative organism isolated was similar to that documented in other reports. Endophthalmitis must be treated with vitrectomy and intra-vitreal injections of antibiotics after a proper vitreous tap.

Stromal differences in odontogenic cysts of a common histopathogenesis but with different biological behavior: a study with picrosirius red and polarizing microscopy

OBJECTIVES

The present study was undertaken to detect and compare the pattern of collagen fibers in odontogenic cysts and also to find out if this methodology could be used to predict the aggressive nature of odontogenic cysts by comparing with the odontogenic tumors.

MATERIALS AND METHODS

The collagen in the wall of 11 odontogenic keratocysts, 14 dentigerous cysts and 14 radicular cysts was studied histochemically by staining sections with picrosirius red and examining under polarizing microscope. This was compared to 10 cases of odontogenic tumors using Z test of proportion at 1% and 5%.

RESULTS

In dentigerous cysts, odontogenic keratocysts and odontogenic tumors, the predominant color of collagen fibers birefringence was found to be orangish red, whereas in radicular cysts the collagen fiber was of green color.

CONCLUSIONS

Similar birefringence pattern of collagen fibers between dentigerous cysts, odontogenic keratocysts and odontogenic tumors may indicate that these lesions have a common histogenesis with a broad spectrum of biological behavior and belong to the same group, i.e., are developmental in origin. Different patterns of radicular cysts suggest different biological behavior and a positive role of inflammation on polarization color of collagen fibers.

Parathyroid hormone and its effects on dental tissues

In the current era, various pharmacological agents exist for osteoporosis management, and synthetic parathyroid hormone (PTH) (Teriparatide, Forteo) is one of the treatment options. Depending on the timing of administration, PTH has a unique ability to cause both bone apposition and bone resorption. This review focuses on the effects of PTH on the bone, specifically the jaw bones mandible and maxilla. The article briefly describes the fundamental mechanism of PTH action at the molecular level, as well as in experimental animals and in humans. It differentiates intermittent administration of PTH, especially at doses tolerated by humans that increase bone strength and prevent bone fractures, from continuous use that may lead to bone loss. In particular, it shows how intermittent administration of PTH can play a significant role in periodontal repair and implant success via stimulation of bone mineral content especially in the pre-alveolar region.

Profile of blood donors and reasons for deferral in coastal South India

BACKGROUND

A blood transfusion is a life-saving procedure in many instances. An adequate supply of safe blood is ensured by exercising donor deferral criteria and screening for Transfusion Transmitted Infections (TTI). The aim of this paper is to study the profile of blood donors and reasons for donor deferral in coastal South India.

METHOD

The study was conducted at a tertiary care hospital in Mangalore. All those who donated between 1 January 2008 and 31 December 2008 were included in the study. Data was collected using a pre-tested semi-structured proforma and analysed using SPSS version 11.5.

RESULTS

Most of the donors were under the age of 25 (42.92%). Donors were predominantly male (95.20%). In terms of occupation, most subjects were students (28.01%) followed by businessmen (18.61%). Slightly more than three-quarters of the donors (77.20%) were replacement donors. The main reasons for deferral were consumption of medication in the past 72 hours (15.15%), hypertension (13.18%), a low haemoglobin level (12.34%) and alcohol intake in the past 72 hours (12.20%). Among the TTIs identified, most samples were positive for Hepatitis B surface Antigen - HBsAg (0.87%) or tested positive for Anti-Hepatitis C (HCV antibodies (0.36%).

CONCLUSION

From the study it was concluded that the majority of the donor population was young and educated. The reason for donation was mainly replacement rather than voluntary. This issue needs to be addressed by exercising proactive measures to increase the number of voluntary, nonremunerated, low-risk donors.

A new approach to simulate characterization of particulate matter employing support vector machines

This paper, for the first time, applies the support vector machines (SVMs) paradigm to identify the optimal segmentation algorithm for physical characterization of particulate matter. Size of the particles is an essential component of physical characterization as larger particles get filtered through nose and throat while smaller particles have detrimental effect on human health. Typical particulate characterization processes involve image reading, preprocessing, segmentation, feature extraction, and representation. Of these various steps, knowledge based selection of optimal image segmentation algorithm (from existing segmentation algorithms) is the key for accurately analyzing the captured images of fine particulate matter. Motivated by the emerging machine-learning concepts, we present a new framework for automating the selection of optimal image segmentation algorithm employing SVMs trained and validated with image feature data. Results show that the SVM method accurately predicts the best segmentation algorithm. As well, an image processing algorithm based on Sobel edge detection is developed and illustrated.

Salvadora persica

Salvadora persica (kharijal) is a large, well-branched, and evergreen shrub or a tree resembling Salvadora oleoides (meethijal) found in the dry and arid regions of India. Chewing sticks have been used for centuries for tooth cleaning, and are recommended by the World Health Organization in areas where their use is customary. Salvadora persica has enormous reported activities. It has potential medicinal and research activities. Salvadora persica is a promising product and is useful to produce antiplaque, analgesic, anticonvulsant, antibacterial, antimycotic, cytotoxic, antifertility, deobstruent, carminative, diuretic, astringent, and also used in biliousness, and rheumatism. This review highlights the pharmacologic effects and therapeutic effects of Salvadora persica. The chemical constituents present in different parts of the plant are also discussed.

Management of infertility in low resource countries

Infertility is a global problem, but the highest prevalence is in low resource countries, particularly in sub-Saharan Africa where infection-related tubal damage is the commonest cause. Most infections causing tubal damage are preventable and assisted conception can treat the infertility. However, assisted conception, despite being available for nearly three decades is either unavailable or inaccessible to most residents of resource poor countries. Infertility has social, economic and personal effects, which go beyond childlessness, and women bear the major brunt of the burden. There is urgent need for a comprehensive sexual and reproductive healthcare initiative involving maternal and child health, safe abortions, family planning and infertility prevention and management. The provision of low cost assisted reproduction for couples in poorly resourced countries also needs to be revisited.

The use of E-test for the drug susceptibility testing of Mycobacterium tuberculosis - a solution or an illusion?

AIM

To evaluate E-test as a tool for rapid determination of drug susceptibility against the conventional LJ method focusing on reliability, expense, ease of standardization and performance of the technique in low resource settings.

MATERIALS AND METHODS

A total of 74 clinical isolates (2004-2005) of Mycobacterium tuberculosis were tested using E-test for susceptibility to streptomycin (STM), isoniazid (INH), rifampicin (RIF) and ethambutol (EMB) by E-strip and LJ (LJPM) proportion methods.

RESULTS

The LJPM method, the gold standard, detected resistance against STM in 16.2%, INH in 40.5%, RIF in 18.9% and EMB in 27% cases. In comparison, the resistance values showed by E-test was 66.67% for STM, 57.14% for INH 71.43% for RIF and 80% for EMB. The susceptible correlation was 90.32% for STM, 73.91% for INH, 93.33% for RIF and 59.26% for EMB. E-test correctly identified only eight of the 12 (66.6%) MDR isolates and wrongly identified four isolates which were not MDR. The overall agreement between the two methods was only 48.6%. Resistant isolates showed false positive resistance observed while using E-strip towards all the drugs.

CONCLUSION

E-strips are not quite feasible as a replacement for LJ-proportion method on a large scale due to high risk of cross contamination, laboratory infection, expense associated with it and high false positive resistance observed to all first line drugs. However, the good correlation observed for RIF between the two methods indicates that E-test could contribute to the role in rapid screening of MDR TB isolates as rifampicin mutations are invariably observed in MDR TB isolates.

Atherosclerosis in Asian Indians with systemic lupus erythematosus

OBJECTIVES

Atherosclerosis has emerged as an important late complication of systemic lupus erythematosus (SLE). Asian Indians, as an ethnic group, are known to be metabolically predisposed to development of early atherosclerosis. No data on this aspect of SLE are available from Asia. This study was undertaken to find the frequency of atherosclerosis in Indian lupus patients and the factors affecting such an occurrence.

METHODS

Carotid artery intimo-medial thickness (IMT) and plaque were used as markers of atherosclerosis. High-resolution B-mode ultrasonography was used to compare carotid IMT and plaque in 50 patients with SLE and 50 age- and sex-matched healthy controls.

RESULTS

Patients with lupus (age 31.6+/-10.05, median 30.5 years; disease duration 52.3+/-36.7, median 46 months) exhibited a significantly greater IMT than controls (0.417+/-0.07 vs. 0.362+/-00.07 mm; p = 0.003). Carotid plaques were seen in seven (14%) cases. None of the control population had plaques (p = 0.006). On bivariate analysis, the IMT was significantly affected by age, systolic blood pressure (SBP), disease duration and menopausal status. On multivariate analysis, the only factor significantly affecting IMT was SBP. The Systemic Lupus International Collaborating Clinics/American College of Rheumatology (SLICC/ACR) score was the sole factor found to significantly affect the occurrence of plaque.

CONCLUSIONS

Asian Indian lupus patients in our study, despite being relatively young and with shorter disease duration, exhibited premature atherosclerosis in the form of significantly thicker intimo-media and plaque. The factors found to affect accelerated atherosclerosis in our cohort were age, SBP, disease duration, postmenopausal status and the SLICC/ACR score.

Age-related decrease in rod bipolar cell density of the human retina: an immunohistochemical study

During normal ageing, the rods (and other neurones) undergo a significant decrease in density in the human retina from the fourth decade of life onward.Since the rods synapse with the rod bipolar cells in the outer plexiform layer, a decline in rod density (mainly due to death)may ultimately cause an associated decline of the neurones which,like the rod bipolar cells,are connected to them.The rod bipolar cells are selectively stained with antibodies to protein kinase C-alpha.This study examined if rod bipolar cell density changes with ageing of the retina, utilizing donor human eyes (age: 6-91 years).The retinas were fixed and their temporal parts from the macula to the mid-periphery sectioned and processed for protein kinase C-alpha immunohistochemistry.The density of the immunopositive rod bipolar cells was estimated in the mid-peripheral retina (eccentricity: 3-5 mm)along the horizontal temporal axis.The results show that while there is little change in the density of the rod bipolar cells from 6 to 35 years (2.2%), the decline during the period from 35 to 62 years is about 21% and between seventh and tenth decades,it is approximately 27%.