Preventive effect of ethanol extract of Alpinia calcarata Rosc on Ehrlich's ascitic carcinoma cell induced malignant ascites in mice

ObjectiveTo explore cytotoxic activity of ethanol extract of Alpinia calcarata Rosc (EEAC) rhizome against Ehrlich ascites carcinoma (EAC) tumor bearing Swiss Albino mice.MethodsIn the present study, its anti-neoplastic activity has been studied by monitoring parameters like tumor weight measurement, survival time, tumor cell growth inhibition, haematological characteristics etc.ResultsIt was found that EEAC at dose 8 mg/kg/day (i.p.) significantly decreased tumor weight (62.0%; P <0.01), increased life span (70.25%; P <0.01) and reduced tumor cell growth rate (85.7%; P <0.01) in comparison to those of EAC bearing mice. The plant extract also improved the depleted haematological parameters like RBC, WBC, Hb%, differential counts (e.g. lymphocytes, neutrophils, monocytes etc) of EAC bearing mice towards normal. The host toxic effects were not very high and recovered gradually towards normal within a few days after treatment.ConclusionsEEAC exhibits potent in vivo cytotoxic activity against EAC tumor bearing Swiss Albino mice. So, the plant can be considered as a probable new source of antitumor agents.     

Antiproliferative effects of novel urea derivatives against human prostate and lung cancer cells; and their inhibition of β-glucuronidase activity

Twenty-one novel urea derivatives were synthesized and their structures characterized by mass, NMR, IR, and UV spectroscopy. These compounds were evaluated for their antiproliferative profile against human PC-3 (prostate) and NCI-H460 (lung) cancer cell lines. Among them, compound 21 N-(3-nitrophenyl)-N′-(1-phenylethyl)urea was found to be active against both PC-3 (IC₅₀ ± SEM: 20.13 ± 0.91 μM) and NCI-H460 (GI₅₀: 22 ± 2.6 μM) cell lines; hence has the potential to be further studied as anticancer agent. These compounds were also investigated for their ability to inhibit urease, β-glucuronidase, and phosphodiesterase enzymes. N-(2,6-Dimethylphenyl)-N′-(4′-nitrophenyl)urea (1) demonstrated 90 % inhibition of β-glucuronidase enzyme (IC₅₀ ± SEM: 3.38 ± 0.043 μM).     

Effects of different types of tooth movement and force magnitudes on the amount of tooth movement and root resorption in rats

Objective:To investigate differences in the amount of tooth movement and root resorption that occurred after tipping and bodily movement of the maxillary first molar in rats.Materials and Methods:Ten-week-old female Wistar rats were divided into two groups according to type of tooth movement and subdivided into four subgroups according to the magnitude of applied force. Nickel-titanium closed-coil springs exerting forces of 10, 25, 50, or 100 g were applied to the maxillary left first molars to induce mesial tooth movement. We designed a novel orthodontic appliance for bodily tooth movement. Tooth movement distance and root resorption were measured using microcomputed tomography and scanning electron and scanning laser microscopy.Results:The amount of tooth movement in the bodily tooth movement group was less than half that in the tipping tooth movement group. The greatest amount of tooth movement occurred in the 10-g tipping and 50-g bodily tooth movement subgroups, and the amount of tooth movement decreased with the application of an excessive magnitude of force. Conversely, root resorption increased when the heavier orthodontic force was applied in both groups. Root resorption in the tipping tooth movement group was approximately twice that in the bodily tooth movement group.Conclusions:Root resorption in the tipping tooth movement group was more pronounced than that in the bodily tooth movement group. Although the amount of tooth movement decreased when extremely heavy forces were applied, root resorption increased in both the tipping and bodily tooth movement groups in rats.     

Cytotoxic C-Methylated Chalcones from Syzygium samarangense.

Abstract

The flavonoids 2′-hydroxy-4′,6′-dimethoxy-3′-methylchalcone (1), 2′,4′-dihydroxy-6′-methoxy-3′,5′-dimethylchalcone (2), 2′,4′-dihydroxy-6′-methoxy-3′-methylchalcone (3), 2′,4′-dihydroxy-6′-methoxy-3′-methyldihydrochalcone (4) and 2′,4′-dihydroxy-6′-methoxy-3′,5′-dimethyldihydrochalcone (5), isolated from Syzygium samarangense. (Blume) Merr. & L.M. Perry (Myrtaceae), were subjected to cytotoxicity testing using the dimethylthiazoldiphenyl tetrazolium (MTT) assay. The cell lines used were the Chinese hamster ovarian (CHO-AA8) and the human mammary adenocarcinoma, (MCF-7 and SKBR-3). Among the test compounds, 2 exhibited significant differential cytotoxicity against the MCF-7 cell line with an IC₅₀ of 0.0015 ± 0.0001 nM. It was also cytotoxic against the SKBR-3 cell line with an IC₅₀ of 0.0128 ± 0.0006 nM. Doxorubicin, the positive control, had an IC₅₀ of 2.60 ± 0.28 × 10^?4 nM against the MCF-7 cell line and an IC₅₀ of 2.76 ± 0.52 × 10^?5 nM against the SKBR-3 cell line. When tested in a mechanism-based yeast bioassay for detecting DNA-damaging agents using genetically engineered Saccharomyces cerevisiae. RS322Y (RAD52) mutant strain and (LF15/11) (RAD+) wild-type strain, 2 showed significant selective cytotoxicity against the RAD52 yeast mutant strain. It had an IC₁₂ of 0.1482 nM, as compared with the positive control, streptonigrin, which had an IC₁₂ of 0.0134 nM. Hence, 2 is a cytotoxic natural product with potential anticancer application.     

Genotype-phenotype correlation in Costello syndrome: HRAS mutation analysis in 43 cases

Background

Costello syndrome (CS) is a rare multiple congenital abnormality syndrome, associated with failure to thrive and developmental delay. One of the more distinctive features in childhood is the development of facial warts, often nasolabial and in other moist body surfaces. Individuals with CS have an increased risk of malignancy, suggested to be about 17%. Recently, mutations in the HRAS gene on chromosome 11p13.3 have been found to cause CS.

Methods

We report here the results of HRAS analysis in 43 individuals with a clinical diagnosis of CS.

Results

Mutations were found in 37 (86%) of patients. Analysis of parental DNA samples was possible in 16 cases for both parents and in three cases for one parent, and confirmed the mutations as de novo in all of these cases. Three novel mutations (G12C, G12E, and K117R) were found in five cases.

Conclusions

These results confirm that CS is caused, in most cases, by heterozygous missense mutations in the proto‐oncogene HRAS. Analysis of the major phenotypic features by mutation suggests a potential correlation between malignancy risk and genotype, which is highest for patients with an uncommon (G12A) substitution. These results confirm that mutation testing for HRAS is a reliable diagnostic test for CS.     

Antimanic-like effect of tamoxifen is not reproduced by acute or chronic administration of medroxyprogesterone or clomiphene

Tamoxifen, a protein kinase C (PKC) inhibitor and antiestrogenic drug, has clinical antimanic effects and blocks psychostimulant-induced hyperlocomotion. Medroxyprogesterone (MPA), which has antiestrogenic effects, also exerts some clinical benefits in female manic patients and partially blocks amphetamine-induced hyperlocomotion, indicating that the antiestrogenic effect of tamoxifen could contribute to its antimanic effect. The present study evaluated the effect of acute and chronic (21 day) treatment of two antiestrogenic drugs, MPA and clomiphene (an estrogenic receptor antagonist), on methylphenidate (MPH, 5.0mg/kg)-induced hyperlocomotion in mice, an animal model of mania. Acute and chronic tamoxifen administration was used as a positive control. Acute and chronic tamoxifen (1.0mg/kg) administration blocked MPH-induced hyperlocomotion. Acute and chronic MPA (acute: 3.0 or 6.0mg/kg; chronic: 3.0mg/kg) and clomiphene (acute: 1.5 or 3.0mg/kg; chronic: 1.5mg/kg) treatment did not alter MPH-induced hyperlocomotion. These results indicate that tamoxifen exerts antimanic-like effects, and reduced estrogenic activity does not have antimanic-like effects in this psychostimulant-induced hyperlocomotion model. Therefore, the antiestrogenic effect of tamoxifen likely does not contribute to its antimanic effect, which may instead be related to its effect on PKC activity. Therefore, PKC inhibition may be associated with the antimanic effect of mood stabilizers.     

Missense and nonsense mutations in the alternatively-spliced exon 2 of COL2A1 cause the ocular variant of Stickler syndrome

Stickler syndrome type I (STL1) is a phenotypically heterogeneous disorder characterized by ocular and extraocular features. It is caused by null-allele mutations in the COL2A1 gene that codes for procollagen II. COL2A1 precursor mRNA undergoes alternative splicing, resulting in two isoforms, a long form including exon 2 (type IIA isoform) and a short form excluding exon 2 (type IIB isoform). The short form is predominantly expressed by differentiated chondrocytes in adult cartilage, and the long form in chondroprogenitor cells during early development and in the vitreous of the eye, which is the only adult tissue containing procollagen IIA. Recent evidence indicates that due to the tissue-specific expression of these two isoforms, premature termination codon mutations in exon 2 cause Stickler syndrome with minimal or no extraocular manifestations. We describe here two mutations in exon 2 of COL2A1 in three patients with predominantly ocular Stickler syndrome: Cys64Stop in two patients, and a novel structural mutation, Cys57Tyr, in one patient. RT-PCR of total lymphoblast RNA from one patient with the Cys64Stop mutation revealed that only the normal allele of the IIA form was present, indicating that the mutation resulted either in complete loss of the allele by nonsense-mediated mRNA decay or by skipping of exon 2 via nonsense-mediated altered splicing, resulting in production of the type IIB isoform. The results of COL2A1 minigene expression studies suggest that both Cys64Stop and Cys57Tyr alter positive cis regulatory elements for splicing, resulting in a lower IIA:IIB ratio.     

Problem based learning

PBL, an educational format, stimulates active and life long learning. PBL improves the motivation of students, stimulates integration of disciplines, small group learning; improves clinical reasoning, problem-solving and decision making. It has been introduced increasingly in the curricula of a number of countries in South-East Asia, viz. Thailand, India, Myanmar and Nepal. We feel that the seed of PBL should be sown in the soil of the Undergraduate Medical Curriculum in Bangladesh urgently.