1.Pneumococcal replicative state in relation to its adherence capacity to A549-cell line: A preliminary in vitro analysis
Mohd Nasir Mohd Desa ; Navaratnam Parasakthi ; Shamala Devi Sekaran ; Jamunarani Vadivelu
Malaysian Journal of Microbiology 2011;7(2):107-110
This study was to compare the replication capacity of pneumococcal isolates (serotypes 1, 7F, 19F and 23F) with their adherence pattern to monolayer cells (A549). For standardization purposes, all isolates showed a normal growth curve in both bacteriological (THB + 0.5% yeast extract with and without 2% FBS) and cell culture media (RPMI + 2% FBS). In the former media, a shorter lag phase was observed for isolate serotypes 1 and 7F in presence of serum while in the later; growth yield was lower for all isolates with stationary phase approaching OD600 of 0.01 as compared to 1.0 in bacteriological media. In the replicative analysis at different growth phases of the isolates in cell culture media, growth capacity at 3 h post-incubation was frequently twice as that at 1 h, and that at early-log phase was frequently higher than that at mid-log phase at both post-incubation times. Adherence was frequently the least at early-log phase although the isolates were in the most active state of replication to increase the number of pneumococcal cells to adhere. At mid- and late-log phases, pneumococcal adherence was frequently higher although the replication was reduced. This study marks the potential correlation between pneumococcal growth fitness and adherence capacity whereby the later may not be superior during the early growth phase.
2.Bilateral thalamic internal medullary lamina involvement in a case of dengue encephalitis
Sherrini Bazir Ahmad ; Chin Sum Cheong ; Shen-Yang Lim ; Kartini Rahmat ; Faizatul Izza Rozalli ; Shamala Devi Sekaran ; Helmi Sulaiman, Sasheela Ponnampalavanar ; Kheng Seang Lim ; Chong Tin Tan
Neurology Asia 2016;21(4):375-379
There are 50-100 million dengue infections each year, but dengue encephalitis is relatively
uncommon. The aetiology of neuronal injury is proposed to be due to direct viral neurotropism or
host immune response-mediated inflammation causing neuronal damage. We report a case of severe
dengue encephalitis, presenting during the acute viraemic phase of the disease. This was associated
with inflammation and haemorrhage of the internal medullary lamina of both thalami which, to our
knowledge, has not yet been reported in other infections of the central nervous system.
Dengue
3. Anti-encystment and amoebicidal activity of Lonicera japonica Thunb. and its major constituent chlorogenic acid in vitro
Tooba MAHBOOB ; Abdul-Majid AZLAN ; Tian-Chye TAN ; Veeranoot NISSAPATORN ; Chandramathi SAMUDI ; Shamala Devi SEKARAN ; Christophe WIART
Asian Pacific Journal of Tropical Medicine 2016;9(9):866-871
Objective To examine the acanthamoebicidal effects of ethyl acetate, aqueous and butanol fractions of dried flower buds of Lonicera japonica (L. japonica) Thunb. (Flos Lonicerae) in vitro. Methods Acanthamoeba triangularis isolates were obtained from environmental water samples and identified by PCR. They were exposed to ethyl acetate, water and butanol fractions of L. japonica Thunb. at concentrations ranging from 0.5 mg/mL to 1.5 mg/mL. The extracts were evaluated for growth inhibition at 24, 48 and 72 h, respectively. Chlorogenic acid at a concentration of 1 mg/mL was examined for inhibition of encystment. Results Ethyl acetate fraction at a concentration of 1.5 mg/mL evoked a significant reduction of trophozoite viability by 48.9% after 24 h, 49.2% after 48 h and 33.7% after 72 h chlorogenic acid, the major active constituent of L. japonica Thunb. at the concentration of 1 mg/mL reduced the cysts/trophozoite ratio by 100% after 24 h, 84.0% after 48 h and 72.3% after 72 h. This phenolic compound at concentration of 1 mg/mL concurrent with 0.6% hydrogen peroxide inhibited hydrogen peroxide-induced encystment by 92.8% at 72 h. Conclusions Results obtained from this study show that ethyl acetate fraction at 1.5 mg/mL is the most potent fraction of L. japonica Thunb. and its major constituent chlorogenic acid showed the remarkable inhibition of encystment at a concentration of 1 mg/mL.