Modification of the o-cresolphthalein complexone method by improving stability of reagents for determination of serum total calcium

Objective: Measurement of total calcium level in serum plays a main role in the diagnosis of many diseases such as osteomalacia, primary hyperparathyroidism and bone metastasis of carcinoma. Commonly used WHO recommended o-cresolphthalein complexone method has some disadvantages such as poor reagent stability, inconvenience in reagent preparation and higher reagent wastage. Therefore this study was performed to develop a new method to measure the total serum calcium by avoiding the weaknesses of the currently employed method. Methods: A comparative study was performed using in-ward adult patient’s serum samples (n=100) received at the Department of Chemical Pathology, National Hospital, Sri Lanka for calcium analysis. They were analyzed by using 4 methods namely; developed method, validated kit method, WHO method and WHO (2000) method. Results: The developed method exhibited linear results of calcium concentration from 2.5 to 15 mg/dl. No significant change in reagent performance over 60 days from preparation was observed. Recovery range was very high in the developed method. The results of the developed method correlated well with the WHO method and other two methods. Conclusion: It was concluded that the developed method for the serum calcium analysis benefits over currently used methods in the Medical Laboratory practice due to the stability of the reagent performance.

Priorities for research and development on small ruminants in Sri Lanka

In IDL-279

Natural rubber latex-clay nanocomposite: use of montmorillonite clay as an alternative for conventional CaCO3

Natural rubber (NR) latex-clay nanocomposite (NRLCN) synthesized with montmorillonite (MMT) clay aqueous dispersion was evaluated for reinforcement and barrier properties. The physio-mechanical properties of the NRLCN were compared with the conventional NR latex composites containing CaCO3. The NRLCN structure was characterized with X-ray diffraction and scanning electron microscope techniques. The X-ray diffraction data showed that, with a lower concentration of clay, a highly exfoliated clay structure was achieved whilst the clay aggregation gradually resulted in a higher concentration of clay. The crosslink density as computed based on the solvent absorption data of the latex nanocomposite films was increased with the increase of clay concentration. As a result of nanoscale dispersion of the montmorillonite clay and higher crosslink density of the latex nanocomposite films, the resistance to permeation of small molecules through the NRLCN was significantly enhanced in comparison to conventional NR latex-CaCO3 composites. Solid state mechanical properties of NRLCNs showed a significant reinforcement effect of dispersed clay platelets but without significantly reducing the elastic properties. The higher mechanical properties and improved barrier resistance indicated that NR latex nanocomposites containing montmorillonite clay is a potential replacement for conventional NR latex composites containing CaCO3

Development of an early detection method for white root disease caused by Rigidoporus microporus

Rigidoporus microporus (Fr.) Overeem has become an increasingly important plant pathogenic fungus in Sri Lanka and in many other countries. This fungus causes white root disease in many economically important agricultural, ornamental and plantation crops such as Rubber, Tea, Coconut, Jack, Bread fruit, Mango, Cashew nuts, Carsmbola, Avacado, Cassava, Cinnamon, Cocoa, Yams, Weeping willows and Teak resulting huge losses to the growers. Moreover, the sacred “bo trees” (Ficus religiosa) and the Sri Lanka‟s national plant “Na tree”, (Mesua ferrea) are also affected. In rubber white root disease is the most destructive root disease in Sri Lankan rubber plantations and is currently spreading at an alarming rate. The disease can be controlled by drenching with systemic fungicides tebuconazole or hexaconazole. For chemical control, early disease diagnosis is important. The disease at present is identified through the foliar symptoms, yellowing and buckling. The characteristic fruit bodies are observed at later stages and by then most plants are beyond redemption. The incapability of identifying the disease during the early stages causes economic losses to the grower and they are continually confronted with this problem. The present study was aimed at developing an early detection technique enabling to overcome the above problem. The use of mulching to detect the fungal growth in artificially inoculated polybag plants is reported. The detection of the disease was by the examination of the collar region of the plants. It was revealed that till 8 weeks no plants showed any rhizomorphs on the collar region. But 10 weeks after mulching, 40% of the plants showed rhizomorphs at the collar region while there was no such growth on the infected plants without the mulch. Twelve weeks after mulching, 80% of the plants showed the fungal growth while after 14 weeks all the plants under investigation were had rhizomorphs at the collar region. The plants infected and kept without mulching did not show any rhizomorphs on the collar region till the 12th week after mulching. After 14 weeks of incubation 10% of the plants without mulching also showed foliar symptoms.. The fungal mycelium is reported to grow superficially as rhizomorphs on Hevea roots and it has also been reported that this epiphytic mycelium always grows well ahead of the area where fungal penetration occurs. This time gap can be effectively used to detect the disease early. Hence, chemical control would become more efficient as the infection is detected during very early stages. However, further investigations are necessary to assess the pathogenicity behind the rapid upward movement of the pathogen and also to demonstrate its applicability under natural field conditions