The cytotoxic effect of Baeckea frustescens extracts in eliminating hypoxic breast cancer cells.

BACKGROUND: Adaptive metabolic response towards a low oxygen environment is essential to maintain rapid tumour proliferation and progression. The vascular network that surrounds the tumour develops an intermittent hypoxic condition and stimulates hypoxia-inducing factors. Baeckea frutescens is used in traditional medicine and known to possess antibacterial and cytoprotective properties. In this study, the cytotoxic effect of B. frutescens leaves and branches extracts against hypoxic human breast cancer (MCF-7) was investigated. METHOD: The extracts were prepared using Soxhlet apparatus for ethanol and hexane extracts while the water extracts were freeze-dried. In vitro cytotoxic activities of B. frutescens extracts of various concentrations (20 to 160 µg/mL) at 24, 48, and 72 hours time points were studied using MTT in chemically induced hypoxic condition and in 3-dimensional in vitro cell culture system. An initial characterisation of B. frutescens extracts was carried out using Fourier-transform Infrared- Attenuated Total Reflection (FTIR-ATR) to determine the presence of functional groups. RESULTS: All leaf extracts except for water showed IC50 values ranging from 23 -158 µg/mL. Hexane extract showed the lowest IC50 value (23 µg/mL), indicating its potent cytotoxic activity. Among the branch extracts, only the 70% ethanolic extract (B70) showed an IC50 value. The hexane leaf extract tested on 3- dimensional cultured cells showed an IC50 value of 17.2 µg/mL. The FTIR-ATR spectroscopy analysis identified various characteristic peak values with different functional groups such as alcohol, alkenes, alkynes, carbonyl, aromatic rings, ethers, ester, and carboxylic acids. Interestingly, the FTIR-ATR spectra report a complex and unique profile of the hexane extract, which warrants further investigation. CONCLUSION: Adaptation of tumour cells to hypoxia significantly contributes to the aggressiveness and chemoresistance of different tumours. The identification of B. frutescens and its possible role in eliminating breast cancer cells in hypoxic conditions defines a new role of natural product that can be utilised as an effective agent that regulates metabolic reprogramming in breast cancer.

Toward improved mechanical, tribological, corrosion and in-vitro bioactivity properties of mixed oxide nanotubes on Ti-6Al-7Nb implant using multi-objective PSO.

Recently, the robust optimization and prediction models have been highly noticed in district of surface engineering and coating techniques to obtain the highest possible output values through least trial and error experiments. Besides, due to necessity of finding the optimum value of dependent variables, the multi-objective metaheuristic models have been proposed to optimize various processes. Herein, oriented mixed oxide nanotubular arrays were grown on Ti-6Al-7Nb (Ti67) implant using physical vapor deposition magnetron sputtering (PVDMS) designed by Taguchi and following electrochemical anodization. The obtained adhesion strength and hardness of Ti67/Nb were modeled by particle swarm optimization (PSO) to predict the outputs performance. According to developed models, multi-objective PSO (MOPSO) run aimed at finding PVDMS inputs to maximize current outputs simultaneously. The provided sputtering parameters were applied as validation experiment and resulted in higher adhesion strength and hardness of interfaced layer with Ti67. The as-deposited Nb layer before and after optimization were anodized in fluoride-base electrolyte for 300min. To crystallize the coatings, the anodically grown mixed oxide TiO2-Nb2O5-Al2O3 nanotubes were annealed at 440°C for 30min. From the FESEM observations, the optimized adhesive Nb interlayer led to further homogeneity of mixed nanotube arrays. As a result of this surface modification, the anodized sample after annealing showed the highest mechanical, tribological, corrosion resistant and in-vitro bioactivity properties, where a thick bone-like apatite layer was formed on the mixed oxide nanotubes surface within 10 days immersion in simulated body fluid (SBF) after applied MOPSO. The novel results of this study can be effective in optimizing a variety of the surface properties of the nanostructured implants.

Optimizing the coagulation process in a drinking water treatment plant -- comparison between traditional and statistical experimental design jar tests.

In this study of coagulation operation, a comparison was made between the optimum jar test values for pH, coagulant and coagulant aid obtained from traditional methods (an adjusted one-factor-at-a-time (OFAT) method) and with central composite design (the standard design of response surface methodology (RSM)). Alum (coagulant) and polymer (coagulant aid) were used to treat a water source with very low pH and high aluminium concentration at Sri-Gading water treatment plant (WTP) Malaysia. The optimum conditions for these factors were chosen when the final turbidity, pH after coagulation and residual aluminium were within 0-5 NTU, 6.5-7.5 and 0-0.20 mg/l respectively. Traditional and RSM jar tests were conducted to find their respective optimum coagulation conditions. It was observed that the optimum dose for alum obtained through the traditional method was 12 mg/l, while the value for polymer was set constant at 0.020 mg/l. Through RSM optimization, the optimum dose for alum was 7 mg/l and for polymer was 0.004 mg/l. Optimum pH for the coagulation operation obtained through traditional methods and RSM was 7.6. The final turbidity, pH after coagulation and residual aluminium recorded were all within acceptable limits. The RSM method was demonstrated to be an appropriate approach for the optimization and was validated by a further test.

The effect of Piper betel extract on the wound healing process in experimentally induced diabetic rats.

BACKGROUND: Piper betel (PB) possesses antimicrobial, antifungal, antioxidant and wound healing properties due to its powerful antioxidant effect. Diabetes mellitus (DM) is a metabolic disorder which is associated with complications like impaired wound healing, nephropathy and neuropathy. The main aim of the study was to study the wound healing properties of PB. MATERIALS AND METHODS: A total of 33 male Sprague-Dawley rats (250-300 g) were taken and divided into 3 groups: Group I (control) comprising of 14 rats; Group II (diabetic untreated) comprising of 9 rats; Group III (diabetic treated) comprising of 10 rats. After 10 days of acclimatization, the animals were fasted overnight and diabetes was induced by administration of streptozotocin (45 mg/Kg body weight in a single dose, through tail vein) to group II and III animals. Four 6 mm-diameter full thickness skin excision wounds were created and PB extract (50 mg diluted in 0.1 ml of normal saline) was applied locally for 10 days in group III. The group I and II received normal saline (0.1 ml) for 10 days. The total protein content and the wound contraction rate were determined. RESULTS: The wound contraction rate of group III (35.03 +/- 2.96) was higher as compared to group II (18.40 +/- 3.87) with p = 0.014. The total protein content for group III was 106.39 +/- 4.46 as compared to group II (72.86 +/- 12.86) with p = 0.050. CONCLUSION: PB acted as a protective agent in the early phase of wound healing by increasing total protein content and wound contraction rate.

Appraisal of latex glove proteins in the induction of sensitivity to multiple latex allergens.

Six Hevea brasiliensis latex protein allergens, Hevb 1, Hev b 2, Hev b 3, Hev b 4, and two variants of Hev b 7 (7b and 7c), were purified from Hevea latex, while a seventh protein, Hev b 5, was prepared in recombinant form. The presence of these proteins in glove extracts was indicated by their respective antibodies in the serum of rabbits immunized against the extracts. The relative propensities of IgE binding to the individual latex allergens were compared using sera from latex-allergic patients. IgE recognition of Hev b 4, Hev b 7b, Hev b 5 and Hev b 2 was most frequently encountered, with 75, 61, 31 and 28%, respectively, of the patient sera reacting. Sensitivity to multiple latex proteins was common, and out of the 31 seropositive patients, 23 (74%/ ) had IgE against at least two latex allergens, while 12 (39%) had IgE specific for at least three allergens. Statistical analysis of the data suggested that many patients might have acquired sensitivity to Hev b 2, Hev b 4 and Hev b 7b from a common source. (e.g., from latex products). On the other hand, sensitivity to Hev b 5 and to Hev b 7c were interrelated. It is plausible that sensitivity to these two proteins might have been acquired from sources other than latex products (e.g., from certain foods).

cDNA cloning of the 43-kDa latex allergen Hev b 7 with sequence similarity to patatins and its expression in the yeast Pichia pastoris.

IgE-mediated hypersensitivity to latex proteins present in health care products, particularly in latex gloves, has become an important public health problem in recent years. We purified natural Hev b 7, a 43-kDa patatin-like allergen from the latex of Hevea brasiliensis and determined several internal peptide sequences. A heterologous hybridization probe of a patatin gene of potato, to which these peptides could be aligned best, was used to screen a latex cDNA library. The cDNA encoded an acidic protein of 388 amino acids with a molecular mass of 42.9 kDa. The deduced amino acid sequence had 39-42% identity to patatins from Solanum tuberosum. The purified recombinant Hev b 7 expressed in the yeast Pichia pastoris displayed, similarly to patatins from S. tuberosum, esterase activity. Both natural and recombinant Hev b 7 were recognized by IgE from sera of latex-sensitized allergic individuals. In contrast to patatins from S. tuberosum and Nicotiana tabacum, natural Hev b 7 lacked an N-terminal leader peptide for targeting to the endoplasmatic reticulum and was not glycosylated. These results establish the 43-kDa patatin-like protein as a latex allergen and raise the possibility of different cellular localization and function compared to S. tuberosum patatins.

Precipitation of Hevea brasiliensis latex proteins with trichloroacetic acid and phosphotungstic acid in preparation for the Lowry protein assay.

Many proteins derived from the latex of Hevea brasiliensis that remain soluble in trichloroacetic acid (TCA) can be precipitated by phosphotungstic acid (PTA). A combination of 5% TCA and 0.2% PTA precipitates a wide range of proteins effectively even when they are present in low concentrations (below 1 microgram ml-1). In addition to its protein purification function, acid precipitation also increases the sensitivity of the subsequent protein assay by allowing the test sample to be concentrated. Another advantage of protein precipitation by TCA and PTA is that very small amounts of protein (of the order of 10 micrograms) can be repeatably recovered without the use of precipitate-bulking agents such as sodium deoxycholate. This general procedure of protein purification and concentration is simple and rapid, but the use of PTA may not be fully compatible with the Bradford protein assay. A modified Lowry microassay is described which enables about 3 micrograms ml-1 to be quantitated at the photometric absorbance of 0.05. When used in conjunction with protein concentration by precipitating with TCA/PTA, approximately 0.4 microgram ml-1 protein present in 6 ml of solution can be assayed.