An Experimental and Numerical Study on Nodular Gel Phantom during Cryotherapy.

BACKGROUND: Cryogen spray cooling is an effective method to treat nodular basal cell carcinoma. OBJECTIVE: To study the effect of spraying distance (z = 27 mm, 18 mm and 9 mm) on a nodular gel phantom and to validate the numerical model. MATERIALS AND METHODS: Liquid nitrogen is sprayed on agarose gel phantom using 0.8 mm nozzle diameter. A two-dimensional Pennes equation with phase change is solved on the axisymmetric non-orthogonal grid. RESULTS: The lethal front is obtained at 4 mm from the gel surface, irrespective of spraying distance and the same is validated with numerical results. The maximum necrotic volume and lethal front achieved by -50C and -25C isotherms seem to have a lower dependence on the spraying distance as opposed to those corresponding to the 0C isotherm. In contrast, the initiation of these parameters is highly dependent on the nozzle to gel height. CONCLUSION: The numerical study presents good agreement with experimental data. The decrease in spraying distance leads to higher rate of maximum ablation volume during freezing, but final ablation volume remained approximately similar.

Identification of mega-environments and rice genotypes for general and specific adaptation to saline and alkaline stresses in India.

In the present study, a total of 53 promising salt-tolerant genotypes were tested across 18 salt-affected diverse locations for three years. An attempt was made to identify ideal test locations and mega-environments using GGE biplot analysis. The CSSRI sodic environment was the most discriminating location in individual years as well as over the years and could be used to screen out unstable and salt-sensitive genotypes. Genotypes CSR36, CSR-2K-219, and CSR-2K-262 were found ideal across years. Overall, Genotypes CSR-2K-219, CSR-2K-262, and CSR-2K-242 were found superior and stable among all genotypes with higher mean yields. Different sets of genotypes emerged as winners in saline soils but not in sodic soils; however, Genotype CSR-2K-262 was the only genotype that was best under both saline and alkaline environments over the years. The lack of repeatable associations among locations and repeatable mega-environment groupings indicated the complexity of soil salinity. Hence, a multi-location and multi-year evaluation is indispensable for evaluating the test sites as well as identifying genotypes with consistently specific and wider adaptation to particular agro-climatic zones. The genotypes identified in the present study could be used for commercial cultivation across edaphically challenged areas for sustainable production.

Aldo-keto reductase-1 (AKR1) protect cellular enzymes from salt stress by detoxifying reactive cytotoxic compounds.

Cytotoxic compounds like reactive carbonyl compounds such as methylglyoxal (MG), melandialdehyde (MDA), besides the ROS accumulate significantly at higher levels under salinity stress conditions and affect lipids and proteins that inhibit plant growth and productivity. The detoxification of these cytotoxic compounds by overexpression of NADPH-dependent Aldo-ketoreductase (AKR1) enzyme enhances the salinity stress tolerance in tobacco. The PsAKR1 overexpression plants showed higher survival and chlorophyll content and reduced MDA, H2O2, and MG levels under NaCl stress. The transgenic plants showed reduced levels of Na+ levels in both root and shoot due to reduced reactive carbonyl compounds (RCCs) and showed enhanced membrane stability resulted in higher root growth and biomass. The increased levels of antioxidant glutathione and enhanced activity of superoxide dismutase (SOD), ascorbate peroxidase (APX) and glutathione reductase (GR) suggest AKR1 could protect these enzymes from the RCC induced protein carbonylation by detoxification process. The transgenics also showed higher activity of delta 1-pyrroline-5- carboxylate synthase (P5CS) enzyme resulted in increasedproline levels to maintain osmotic homeostasis. The results demonstrates that the AKR1 protects proteins or enzymes that are involved in scavenging of cytotoxic compounds by detoxifying RCCs generated under salinity stress.

A Novel Adjuvant-Solution Layer Strategy for Improving the Efficacy of Cryosurgery.

BACKGROUND: During cryosurgery, studies reported earlier suggest increased destruction inside the tumour due to adjuvants or the prevention of damage to neighbouring healthy tissue through different methods. OBJECTIVE: This study advocates a novel strategy that increases the freezing inside agarose gel phantoms by addition of glycine and limits the freezing to the desired location using a perfluorohexane layer during cryosurgery. MATERIALS AND METHODS: Cryosurgery of glycine containing gels is carried out with and without perfluorohexane layer and the thermal history is measured using K-type thermocouples connected to a data acquisition system. RESULTS: The presence of glycine causes increased freezing during cryosurgery with an ice ball depth of 16 mm, while with a perfluorohexane layer at this gel interface, this depth is 13 mm, indicating the ability of this layer to limit freezing. CONCLUSION: It can be concluded that glycine addition results in substantial temperature decrease and perfluorohexane layer insulates the glycine gel effectively during cryosurgical cooling.

Neonatal exposure to 17ß-estradiol down-regulates the expression of synaptogenesis related genes in selected brain regions of adult female rats.

AIMS: Administration of estradiol or compounds with estrogenic activity to newborn female rats results in irreversible masculinization as well as defeminization in the brain and the animals exhibit altered reproductive behavior as adults. The cellular and molecular mechanism involved in inducing the irreversible changes is largely unknown. In the present study, we have monitored the changes in the expression of selected synaptogenesis related genes in the sexually dimorphic brain regions such as POA, hypothalamus and pituitary following 17ß-estradiol administration to neonatal female rats. MAIN METHODS: Female Wistar rats which were administered 17ß-estradiol on day 2 and 3 after birth were sacrificed 120days later and the expression levels of genes implicated in synaptogenesis were monitored by semi-quantitative reverse transcription PCR. Since estradiol induced up-regulation of COX-2 in POA is a marker for estradiol induced masculinization as well as defeminization, in the present study only animals in which the increase in expression of COX-2 gene was observed in POA were included in the study. KEY FINDINGS: Down-regulation of genes such as NMDA-2B, NETRIN-1, BDNF, MT-5 MMP and TNF-α was observed in the pre-optic area of neonatally E2 treated female rat brain but not in hypothalamus and pituitary compared to the vehicle- treated controls as assessed by RT-PCR and Western blot analysis. SIGNIFICANCE: Our results suggest a possibility that down-regulation of genes associated with synaptogenesis in POA, may be resulting in disruption of the cyclical regulation of hormone secretion by pituitary the consequence of which could be infertility and altered reproductive behavior.

Cryopreservation of hMSCs seeded silk nanofibers based tissue engineered constructs.

Long term cryopreservation of tissue engineering constructs is of paramount importance to meet off-the shelf requirements for medical applications. In the present study, the effect of cryopreservation using natural osmolytes such as trehalose and ectoin with and without conventional Me2SO on the cryopreservation of tissue engineered constructs (TECs) was evaluated. MSCs derived from umbilical cord were seeded on electrospun nanofibrous silk fibroin scaffolds and cultured to develop TECs. TECs were subjected to controlled rate freezing using nine different freezing solutions. Among these, freezing medium consisting of natural osmolytes like trehalose (40mM), ectoin (40mM), catalase (100µg) as antioxidant and Me2SO (2.5%) was found to be the most effective. Optimality of the chosen cryoprotectants was confirmed by cell viability (PI live/dead staining), cell proliferation (MTT assay), microstructure analysis (SEM), membrane integrity (confocal microscopy) and in vitro osteogenic differentiation (ALP assay, RT-PCR and histology) study carried out with post-thaw cryopreserved TECs. The mechanical integrity of the cryopreserved scaffold was found to be unaltered. The performance of the freezing medium towards cryopreservation of TEC was superior than the performance achieved using conventional Me2SO and similar to the non cryopreserved TEC. Overall we have formulated an efficient freezing medium that may pave the way of long term preservation of TECs with maintaining its integrity, MSCs viability and differentiation potentiality. It was observed that the performance of freezing medium for cryopreservation of TECs was better than the Me2SO.

Effect of lead on growth, protein and biosorption capacity of Bacillus cereus isolated from industrial effluent.

A bacterial strain (Bacillus cereus) with the ability to grow under conditions of high concentrations of lead was isolated from the industrial effluent collected from Peenya Industrial Area, Bangalore. The effect of lead on growth, protein content and lead biosorption capacity of Bacillus cereus was investigated. The results revealed that with increase in lead concentration (100, 200, 300, 400 and 500 mg I(-1)) there was a decrease in growth, protein content (10.6, 8.2, 6.7, 3.8 and 1.9 mg g(-1) d. wt.) and lead biosorption (90.3, 57.8, 48.94, 31.3 and 22.24%) Bacillus cereus, signifying toxic effect of lead on the bacterial strain. Plasmid DNA was isolated from Bacillus cereus to study its resistance mechanism. The size of the plasmid was approximately 33kb. Transformation results suggest that lead resistance gene may be present on the chromosomal DNA ratherthan the plasmid DNA as the transformants did not show lead resistance.

Tissue-specific differential induction of ornithine aminotransferase by estradiol in rats of various ages.

The level and induction of ornithine aminotransferase of the liver and kidney cortex were determined at different phases of the life span of female rats. The level of this enzyme in the liver did not change significantly till adulthood and decreased thereafter. However, there was no significant differences in the level of this enzyme in the kidney cortex of the rat throughout its life span. Further, the level of this enzyme in the kidney cortex was more than 2.5-fold higher than that of the liver in all the age groups. Ovariectomy decreased, and 17-beta-estradiol increased significantly, the activity of the kidney cortex enzyme in rats except for the old ones. The effects of both these treatments were highest in the young-adult (13-weeks) rats. In contrast, the liver enzyme was irresponsive towards both these treatments.

Effects of age and substrate on the circadian rhythm of liver tryptophan pyrrolase of female rats.

The level of tryptophan pyrrolase does not change significantly throughout the 24 hr cycle of the day in rat liver. Young and adult rats show a similar trend in the activity pattern of this enzyme. However, the activity pattern is altered in the post-reproductive rats. L-tryptophan induces liver tryptophan pyrrolase in rats of all the ages. Maximum induction is observed in the post-reproductive rats as compared to the young and adult rats. Further, the degree of induction of this enzyme by its substrate is also affected by the age of the rat.

Comparative studies on myosin ATPase of a flying and nonflying bird.

Myosin was purified from the flight muscles of a flying (pigeon) and a nonflying (fowl) bird. Ki (ADP) of myosin ATPase of pigeon is higher, but the Km (ATP) is lower than that of fowl. The specific activity (mumole of Pi liberated/min/mg protein) is higher for the fowl. A0.5 (CaCl2) of myosin of both pigeon and fowl is similar. However, the two proteins differ in their interactions with ADP, ATP and p-chloromercuribenzoate. The two proteins have the same tyrosine, tryptophan and sulfhydryl contents. The electrophoretic patterns of the two myosins on SDS-polyacrylamide gels are different. These studies show significant molecular differences in the myosin derived from the flight muscles of a flying (pigeon) and a nonflying (fowl) bird.