St. Thomas College, Palai

About: St. Thomas College, Palai is a based out in . It is known for research contribution in the topics: Dielectric & X-ray photoelectron spectroscopy. The organization has 73 authors who have published 97 publications receiving 448 citations.

Analysis of sparse data in logistic regression in medical research: A newer approach

Abstract: Background and Objective: In the analysis of dichotomous type response variable, logistic regression is usually used. However, the performance of logistic regression in the presence of sparse data is questionable. In such a situation, a common problem is the presence of high odds ratios (ORs) with very wide 95% confidence interval (CI) (OR: >999.999, 95% CI: 999.999). In this paper, we addressed this issue by using penalized logistic regression (PLR) method. Materials and Methods: Data from case-control study on hyponatremia and hiccups conducted in Christian Medical College, Vellore, Tamil Nadu, India was used. The outcome variable was the presence/absence of hiccups and the main exposure variable was the status of hyponatremia. Simulation dataset was created with different sample sizes and with a different number of covariates. Results: A total of 23 cases and 50 controls were used for the analysis of ordinary and PLR methods. The main exposure variable hyponatremia was present in nine (39.13%) of the cases and in four (8.0%) of the controls. Of the 23 hiccup cases, all were males and among the controls, 46 (92.0%) were males. Thus, the complete separation between gender and the disease group led into an infinite OR with 95% CI (OR: >999.999, 95% CI: 999.999) whereas there was a finite and consistent regression coefficient for gender (OR: 5.35; 95% CI: 0.42, 816.48) using PLR. After adjusting for all the confounding variables, hyponatremia entailed 7.9 (95% CI: 2.06, 38.86) times higher risk for the development of hiccups as was found using PLR whereas there was an overestimation of risk OR: 10.76 (95% CI: 2.17, 53.41) using the conventional method. Simulation experiment shows that the estimated coverage probability of this method is near the nominal level of 95% even for small sample sizes and for a large number of covariates. Conclusions: PLR is almost equal to the ordinary logistic regression when the sample size is large and is superior in small cell values.

Comparative phytochemical and anti‑bacterial studies of two indigenous medicinal plants Curcuma caesia Roxb. and Curcuma aeruginosa Roxb

Abstract: Background: Traditional medicinal plants could serve as a good supply of new dependable, biodegradable, renewable drugs and can be utilised for its anti‑bacterial activity directly or indirectly. Aims: To evaluate the phytochemical and anti‑bacterial properties of two morphologically similar indigenous medicinal plants Curcuma caesia and Curcuma aeruginosa belonging to the family Zingiberaceae. Materials and Methods: Evaluation of rhizome extracts using methanol was performed for the presence of active principles. Qualitative analysis was carried out for diverse phytoconstituents. Different concentrations (1.25, 2.5, 5.0 mg/ml) of hexane, chloroform, ethyl acetate, acetone, methanol and water serial extracts from the rhizome of C. caesia and C. aeruginosa were tested against Gram positive (Staphylococcus aureus, Streptococcus haemolyticus and Bacillus cereus) and Gram negative (Salmonella typhi, Enterobacter aerogens, Vibrio cholerae, Pseudomonas aeruginosa and Serratia marcescens) bacteria. National Committee for Clinical Laboratory Standard (NCCL) standards were strictly followed to perform anti‑bacterial disc susceptibility test using disc diffusion method. Statistical Analysis: All the values of the results were expressed as means of two independent experiments ± standard deviation. Results: Phytochemical screening of these two plants confirmed the presence of various bioactive substances and thus validating its use in herbal remedies. Anti‑bacterial studies showed varying degree of inhibitory action against all the tested bacteria. Among the Gram positive bacteria, acetone extract of C. caesia showed maximum activity against S. aureus and hexane extract of C. aeruginosa exhibited maximum activity against B. cereus. In Gram negative bacteria, chloroform extract of C. caesia showed maximum inhibitory action against S. marcescens, whereas the methanol extract of C. aeruginosa showed higher inhibitory action against S. typhi. Conclusions: The findings about present study suggest that the rhizome extract possess excellent anti‑bacterial potential that can be used for therapeutic purposes for many bacterial infectious diseases with proper evaluation procedures. The present study validated the use of these plants in traditional medicine and recommends for making new pharmaceuticals for therapeutic needs. Key words: Anti‑bacterial activity, Curcuma aeruginosa, Curcuma caesia, medicinal plants, plant extracts

Asymbiotic seed germination and in vitro conservation of Coelogyne nervosa A. Rich. an endemic orchid to Western Ghats

Abstract: Coelogyne nervosa is an epiphytic orchid endemic to Western Ghats, South India. The mature seeds of C. nervosa were cultured on ½ MS (Murashige and Skoog), MS, Kn (Knudson) and VW (Vacin and Went) media to evaluate the seed germination response. Of the four basal media used, MS medium supported maximum seed germination. Further experiments to enhance seed germination were done on MS medium supplemented with various concentrations (10, 20, 30 and 40 %) of coconut water (CW). Thirty percent CW gave the highest response in terms of percent seed germination (96), fresh weight (7.2 mg/seedling) and protocorm length (15.2 mm). Since CW containing medium did not support further seedling growth, each seedling was isolated and cultured on MS medium supplemented with either BA (6-benzylaminopurine) or Kin (kinetin) alone (1.0–4.0 mg/l each) or in combination with NAA (1-naphthaleneacetic acid; 0.2–1.0 mg/l). Maximum growth was observed on MS medium supplemented with BA (3.0 mg/l) and NAA (0.5 mg/l). On this medium, the seedlings reached an average length of 3.6 cm with 2.8 well expanded green leaves per seedling. Similarly optimum, healthy, white root induction (3.3 roots/seedlings) was also observed on the same medium. The rooted seedlings were successfully transplanted to pots with 91 % success. The 2-year-old tissue culture derived plants produced normal flowers and fruits.