Geeta Talukder

Prevention of cytotoxic effects of arsenic by short-term dietary supplementation with selenium in mice in vivo.

Interaction between selenium and arsenic has been used to protect against the genotoxic effects of sodium arsenite through dietary intervention by an equivalent amount (1/10 LD50) of sodium selenite. The two salts were administered by gavaging to laboratory bred Swiss albino mice sequentially and in combination. Cytogenetic endpoints, including chromosomal aberrations (CA) and damaged cells (DC) were recorded 24 h after exposure from chromosome spreads in bone marrow cells. Administration of sodium selenite 1 h before sodium arsenite reduced the clastogenic effects of the latter significantly. The protection was less when the salts were given together and negative when arsenite was given before selenite. Histological changes were recorded. Such reduction of arsenic toxicity through dietary intervention by selenium is of significance in protecting against the widespread toxicity observed in human populations exposed to arsenic through drinking water from contaminated deep tubewells in West Bengal and Bangladesh.

Protection against cytotoxic effects of arsenic by dietary supplementation with crude extract of Emblica officinalis fruit

Dietary administration of a crude aqueous extract of Emblica officinalis Gaertn. fruit reduced significantly the cytotoxic effects of sodium arsenite administered orally. The crude extract (685u2005mg/kg bw) was given daily by gavaging to age and sex matched laboratory bread Swiss albino mice for 7 and 14 days, followed by a single dose of sodium arsenite (2.5u2005mg/kg bwu2005=u20051/10 of LD50). The animals were killed after 24u2005h and chromosome preparations made following a schedule of colchicine–fixative–air drying–Giemsa. The endpoints screened were chromosomal aberrations and damaged cells. The crude extract reduced arsenic damage bringing the cells almost to the normal level. Copyright

Dietary garlic extract in modifying clastogenic effects of inorganic arsenic in mice: two-generation studies

Mice are fed by gavage crude garlic extract (100 mg/kg b.wt.) for 30 consecutive days. One set was administered sodium arsenite (0.1 mg/kg b.wt.) simultaneously. Another set was treated with sodium arsenite only. Mice given distilled water were kept as negative control. Exposed mice from each set were sacrificed and bone marrow preparations examined for chromosomal aberrations and damaged cells. Sodium arsenite is a strong clastogen and the effects were reduced to a significant level by prolonged administration of garlic extract. For F1 studies, exposed male mice were mated with exposed female mice, and the progeny examined. In the progeny, clastogenic effects of sodium arsenite persisted in a lower degree, indicating that the metal is able to cross the transplacental barrier. There was no statistically significant difference between the effect in progeny of parents only given sodium arsenite when given simultaneously for prolonged periods in the parents; however, the effect is meagre in the next generation.

Chromosome damage induced by selenium salts in human peripheral lymphocytes

Two inorganic salts of selenium, sodium selenite (Na(2)SeO(3)) and sodium selenate (Na(2)SeO(4)), were screened for damage to chromosome and cell division following exposure to human lymphocyte cultures. In vitro exposure of human peripheral blood lymphocytes to high concentration of two inorganic salts of selenium-sodium selenite (2.9 x 10(-5) M) and sodium selenate (2.65 x 10(-5) M)-was found to be lethal; no blast cells being formed. Lower concentrations of both salts, 5.8 x 10(-6) M and 1.06 x 10(-5) M, respectively, were highly mitostatic. Lower concentrations of sodium selenite (2.9 x 10(-6) M, 1.16 x 10(-6) M and 2.32 x 10(-7) M) and sodium selenate (5.3 x 10(-6) M, 2.65 x 10(-6) M and 1.06 x 10(-6) M), respectively, induced chromosomal aberrations and reduced cell division in proportions directly related to the dose. Sodium selenite was considerably more clastogenic than sodium selenate.

Selenium salts and chromosome damage.

Sodium selenite and sodium selenate, fed by gavaging to age-matched male Swiss albino mice and observed after 24 h following a colchicine-fixative-air drying-Giemsa schedule, were found to induce chromosome breaks and spindle disturbances in bone marrow cells. The four concentrations used were fractions of LD50 and the effects were directly proportionate to the concentration of the chemical. Sodium selenite induced a slightly higher frequency of chromosomal aberrations than sodium selenate.

Chlorophyll and chromosome breakage

Increased consumption of green vegetables in the diet has been associated with protection against carcinogenic effects and related mutagenic and clastogenic (chromosome breaking) activity of genotoxic agents. Chlorophyll, present in all green plant parts, has been suggested to be a major protective factor in the process. We have, however, observed that while a crude aqueous extract of Indian spinach leaf significantly reduced genotoxic effects, chlorophyll alone was ineffective. On the other hand, chlorophyll, both as an aqueous extract from the leaf and in a purified commercial form, induced a significantly high frequency of chromosome breaks in bone marrow cells of mice on oral administration. The crude aqueous extract of the leaf was non-toxic. The protective activity of the crude leaf extract may be attributed to the total effect of the interaction between different components, in which the clastogenicity of chlorophyll has been neutralized.

Effects of crude garlic extract on mouse chromosomes in vivo

Three concentrations (25, 50 and 100 mg/kg body weight) of fresh garlic (Allium sativum L.) were administered daily by gavage to Swiss albino mice for different durations up to 60 days. These concentrations had been observed to protect significantly against effects of known clastogens. The endpoints scored were frequencies of chromosomal aberrations and damaged cells induced in bone marrow preparations. These parameters were found to be directly dose dependent and after an initial enhancement at 7 days, were reduced following prolonged exposure for 30 and 60 days to the low level observed at 24 hr. Therefore, administration of a low concentration of garlic extract daily is suggested for at least 30 days to obtain the maximum benefit of the extract in protecting against the clastogenic effects of known genotoxicants.

Interaction of different hemoglobinopathies in Eastern India with a view to establish genotype-phenotype correlation.

Analysis of the molecular basis of hemoglobinopathies provides an opportunity to define genotype–phenotype variations as well as establish the origin of mutation. The present study deals with a large cohort of 1,661 cases referred to the counseling unit and 889 individuals from random screening of the population of Tripura. Characterization of mutation in 291 cases (582 alleles) was performed by the PCR‐ARMS method using genomic DNA. The haplotype of 56 βE mutation‐bearing chromosomes were identified by the RFLP‐PCR method. Genotypes were constructed and correlated with hematological and clinical phenotypes. IVS‐1nt 5 (G→C) mutation was observed as the most frequent mutation, followed by codon 30 (G→C). Production of HbE was significantly (P < 0.001) higher in nontransfusion‐dependent Eβ‐thalassemia patients. βE mutation was observed only on four haplotypes linked to framework 2. Type 2 haplotype was observed mainly from chromosomes of Tripura origin, but none from South Bengal. Homozygous E individuals with 1//1 genotype were significantly (P < 0.01) more anemic compared to individuals with 2//2 genotype. This work creates a database of hemoglobinopathy mutations for the population of Eastern India which will facilitate prenatal diagnosis and counseling. Am. J. Hum. Biol. 12:454–459, 2000.

Modification of Cytotoxic Effects of Inorganic Arsenic by a Crude Extract of Allium sativum L. in Mice

AbstractA crude extract of Allium sativum (100 mg/kg b.w./day) was administered orally to Swiss albino mice with a normal diet for 30 days. Sodium arsenite, a known cytotoxic agent, was given subcutaneously in normal saline to mice (0.1 mg/kg b.w. = 1/50 of LD50) on days 7,14,21 AND 30 of experiments. Chromosomal studies were conducted on bone marrow preparations following the colchicine-air-drying Giemsa schedule. The frequency of chromosomal aberrations was significantly lower in animals maintained on crude plant extract as a dietary supplement during exposure to sodium arsenite as compared to those treated with arsenite alone. A crude extract of Allium sativum thus protects against the clastogenicity of sodium arsenite.

Genetic Causes of Congenital Malformation in India

Abstract Congenital malformations are a major cause of death of neonates in India where prenatal detection and treatment are not adequate in many hospitals and health centers. Incidence is specially high in stillbirths. It is not realized that genetic causes - chromosomal, single gene and polygenic - are the main causes of many congenital defects and early detection and prevention should be essential to make the small family norm a success.