Effect of heat, pH and coating process with stearic acid using a fluidized bed granulator on viability of probiotic Lactobacillus reuteri C 10

This study was conducted to investigate the use of a fluidized bed granulator to coat a probiotic Lactobacillus reuteri C 10 with stearic acid with a view to enhance its survival rate during storage. L reuteri C 10 cells of two treatments, namely, freeze-dried cells incorporated with trehalose and sucrose as cryoprotectants prior to freeze-drying, and freeze-dried cells without any incorporation of cryoprotectants were evaluated. Since the pH of stearic acid is 5.5 and the melting point is 57.23°C, and the inlet temperature of the fluidized bed granulator could be as high as 70°C, a preliminary study was initiated to determine the tolerance of L. reuteri C 10 cells to heat exposure from 58 to 70°C and acidic conditions of pH 4 to 6 for 60 min, during which the cell viabilities were determined every 15 min. In the coating process, 2:3 ratio of freeze-dried L. reuteri C 10 cells and stearic acid, fluidization air of 20 to 50 rpm, coating rate of 40 to 80 g/min and inlet and outlet temperatures of between 50 to 70°C were assessed for optimization of the fluidized bed granulator. Results of the  preliminary study showed that freeze-dried L. reuteri C 10 cells incorporated with cryoprotectants exhibited significantly (P < 0.05) less cell loss than cells without cryoprotectants when exposed to 62°C for 15 to 60 min, 64 °C for 15 to 30 min, 66°C for 30 min and 68°C for 15 to 30 min. Freeze-dried L. reuteri C 10 cells with cryoprotectants were also able to survive for 15 min at 70°C, but not freeze-dried L. reuteri C 10 cells without cryoprotectants. Freeze-dried L. reuteri C 10 cells with or without cryoprotectants could tolerate acidic conditions and there was growth and increase in cell viability at pH 4, 5 and 6. However, cells with cryoprotectants had significantly (P < 0.05) more growth when exposed to pH 5 for 30 to 60 min, and pH 6 for 15 to 60 min than cells without cryoprotectants. The application of a fluidized bed granulator to coat L. reuteri C 10 cells with or without cryoprotectants with melted stearic was not successful in this study because the fluidized bed granulator could not maintain the temperature of stearic acid above its melting point which led to clogging of the tube and spray nozzle of the fluidized bed granulator or resulted in the formation of a big lump of stearic acid and L. reuteri C 10 cells instead of uniform coated cell granules. Installation of a temperature jacket on the fluidized bed granulator may be necessary to control the temperature of stearic acid in the tube and spray nozzle above melting point.Key words: Coating, fluidized bed granulator, Lactobacillus reuteri C10, stearic acid

Transbronchial needle aspiration of mediastinal lymph node

In Malaysia, transbronchial needle aspiration (TBNA) is a relatively new procedure performed only in a handful of respiratory centres. We reviewed TBNA of mediastinal lymph node performed in Hospital Tengku Ampuan Afzan (HTAA) to determine the yield and its complications. Data was retrieved from endoscopy databases and patients' records, CT thorax images and all cytological and histological slides were reviewed. Twenty-five patients had TBNA performed. TBNA was positive in 15 patients (60%). Overall, 80% had confirmed malignancy after bronchoscopy. Only four patients had documented bleeding after TBNA and in two of them, bleeding stopped spontaneously and another two patients required diluted adrenaline to stop the bleed. No mortality was reported from this procedure. Hence, TBNA is a safe procedure

Protein Microarray On-Demand: A Novel Protein Microarray System

We describe a novel, simple and low-cost protein microarray strategy wherein the microarrays are generated by printing expression ready plasmid DNAs onto slides that can be converted into protein arrays on-demand. The printed expression plasmids serve dual purposes as they not only direct the synthesis of the protein of interest; they also serve to capture the newly synthesized proteins through a high affinity DNA-protein interaction. To accomplish this we have exploited the high-affinity binding (∼3–7×10 −13 M) of E. coli Tus protein to Ter, a 20 bp DNA sequence involved in the regulation of E. coli DNA replication. In our system, each protein of interest is synthesized as a Tus fusion protein and each expression construct directing the protein synthesis contains embedded Ter DNA sequence. The embedded Ter sequence functions as a capture reagent for the newly synthesized Tus fusion protein. This “all DNA” microarray can be converted to a protein microarray on-demand without need for any additional capture reagent.

Cytotoxic and antibacterial activities of endophytic fungi isolated from plants at the National Park, Pahang, Malaysia

<p>Abstract</p> <p>Background</p> <p>Endophytes, microorganisms which reside in plant tissues, have potential in producing novel metabolites for exploitation in medicine. Cytotoxic and antibacterial activities of a total of 300 endophytic fungi were investigated.</p> <p>Methods</p> <p>Endophytic fungi were isolated from various parts of 43 plants from the National Park Pahang, Malaysia. Extracts from solid state culture were tested for cytotoxicity against a number of cancer cell lines using the MTT assay. Antibacterial activity was determined using the disc diffusion method.</p> <p>Results</p> <p>A total of 300 endophytes were isolated from various parts of plants from the National Park, Pahang. 3.3% of extracts showed potent (IC₅₀< 0.01 μg/ml) cytotoxic activity against the murine leukemic P388 cell line and 1.7% against a human chronic myeloid leukemic cell line K562. <it>Sporothrix </it>sp. (KK29FL1) isolated from <it>Costus speciosus </it>showed strong cytotoxicity against colorectal carcinoma (HCT116) and human breast adenocarcinoma (MCF7) cell lines with IC₅₀values of 0.05 μg/ml and 0.02 μg/ml, respectively. Antibacterial activity was demonstrated for 8% of the extracts.</p> <p>Conclusion</p> <p>Results indicate the potential for production of bioactive agents from endophytes of the tropical rainforest flora.</p

Evaluation of the surface roughness of three heat-cured acrylic denture base resins with different conventional lathe polishing techniques: A comparative study

Purpose: Surface roughness promotes adhesion and colonization of denture plaque. Therefore, it is important to know the effects of polishing and finishing on the surface roughness of various acrylic resin materials. Objectives: To evaluate and compare the effects of different conventional lathe polishing techniques on heat cured acrylic resins in producing surface roughness. Materials and Methods: Three different commercially available heat-cured acrylic resin materials namely DPI, Meliodent and Trevalon Hi were selected. 30 Specimens of each acrylic material (30 x 3 = 90, 10 x 60 x 2mm) were prepared and divided into 5 groups, each group consisted of 6 Nos. of specimens per material(6x3=18) and were grouped as Group A(unfinished), Group B (finished), Group C (Polishing Paste), Group D (Polishing Cake) and Group E (Pumice and Gold rouge). The resulted surface roughness (µm) was measured using Perthometer and observed under Scanning Electron Microscope. The values obtained were subjected statistical analyses. Results: Among the materials tested, better results were obtained with Trevalon Hi followed by Meliodent and DPI. Among the polishing methods used, superior results were obtained with universal polishing paste followed by polishing cake; Pumice and Gold rouge. Although Pumice and Gold rouge values produced greater roughness value, they were well within the threshold value of 0.2 mm