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M Karan

Publications and source records attributed to M Karan.

9 recordsLinked to original sources
PubMed2006

Comparative macroanatomical study of the neurocranium in some carnivora.

This study was carried out to investigate the specific anatomical features of the neurocranium of the skull of the dog, cat, badger, marten and otter. Twenty-five animals (five from each species) were used without sexual distinction. The neurocranium consists of os occipitale, os sphenoidale, os pterygoideum, os ethmoidale, vomer, os temporale, os parietale and os frontale. The processus paracondylaris is projected ventrally in the cat, dog, marten and badger, and caudally in the otter. Two foramina were found laterally on each side of the protuberantia occipitalis externa in the otter, and one foramen was found near the protuberantia occipitalis externa in the badger. Foramen was not seen in other species. Paired ossa parietalia joined each other at the midline, forming the sutura sagittalis in the badger, dog, otter and cat while it was separated by the linea temporalis in the marten. The os frontale was small in otters, narrow and long in martens, and quite wide in cats and dogs. The bulla tympanica was rounded in the marten, dog, cat and badger, dorsoventral compressed in otter, and it was very large in all species examined. These observations represented interspecies differences in the neurocranium of marten, otter, badger, cat and dog.

Animals↗
PubMed2001

Additional rep-encoding DNAs associated with banana bunchy top virus.

Banana bunchy top nanovirus (BBTV) has a multicomponent circular single-stranded DNA (cssDNA) genome consisting of at least six components. We have cloned, sequenced and analysed two additional cssDNA components, designated BBTV-S1 and S2, associated with a Taiwanese BBTV isolate. The sequences of BBTV-S1 and S2 comprised 1109 and 1095 nucleotides (nt), respectively, and like BBTV DNA-1, potentially encoded replication initiation proteins (Reps). However, the genome organisation of BBTV-S1 and S2 differed from that of BBTV DNA-1 in that (i) the stem sequence of the CR-SL was not conserved, (ii) the internal gene was absent and (iii) the probable TATA boxes were located 5' of the stem-loop. Further, sequence and phylogenetic analysis of the Rep genes indicated that BBTV DNA-S1 and S2 were distinct from BBTV DNA-1. When different geographical isolates of BBTV were tested for the presence of BBTV-S1/S2, these components were detected in various isolates from Vietnam, Taiwan, the Philippines, Tonga and Samoa but were not detected in isolates from Australia, Egypt, Fiji, and India. Based on these results, BBTV-S1 and S2 do not appear to be integral components of the BBTV genome and represent additional Rep-encoding DNAs associated with BBTV.

Amino Acid Sequence↗
PubMed2001

Screening of various Swertia species extracts in primary monolayer cultures of rat hepatocytes against carbon tetrachloride- and paracetamol-induced toxicity.

Swertia chirata Buch-Ham. (Gentianaceae), one of the oldest medicinal herbs of India, is a source of the Indian ayurvedic drug 'chirata' used for the treatment of liver disorders and malarial fevers. In this study, eight species of Swertia were collected. Each of the dry whole plant was extracted into methanol, the aqueous extract of which was sequentially extracted into hexane, chloroform and butanol extracts. The extracts were screened for their anti-hepatotoxic activity against carbon tetrachloride (CCl4) and paracetamol (acetaminophen (AAP)) toxicity in primary monolayer cultures of rat hepatocytes. The primary cultures, 2.5 x 10(6) cells /3 ml medium/60 mm collagen-coated plates, were exposed to 2.5 mM CCl4 or 12 mM AAP in the presence or absence of plant extracts (100 microg/ml culture medium). Cells and medium were harvested after 22 h of treatment for the assay of cellular reduced gluthathione (GSH) content and leakage of lactate dehydrogenase as biological end-points of toxicity. Both CCl4 and AAP at the indicated concentrations reduced GSH by almost 50 and 80%, respectively, while the enzyme leakage was almost 15% above the untreated control. Hexane and methanol extracts of most of the species in general offered relatively good protection. The anti-hepatotoxic activity, nevertheless, was evident in all Swertia species against both the toxicants. However, Swertia purpurascens, Swertia chirata, Swertia paniculata and Swertia cordata exhibited better activity compared with other species investigated. In addition, influence of various extracts (10-100 microg/ml medium) was examined on cellular growth of rat Reuber hepatoma cell line H4IIEC3/G-. Except for the butanol extract of S. chirata, no other extracts exerted toxicity in terms of neutral red uptake by the cells.

Acetaminophen↗
PubMed1999

Antihepatotoxic activity of Swertia chirata on carbon tetrachloride induced hepatotoxicity in rats.

The methanol extract of Swertia chirata was evaluated for antihepatotoxic activity against carbon tetrachloride induced liver toxicity in experimental rats. The extract was found to be active and on fractionation into butanol soluble and chloroform soluble fractions, the activity was traced and found more profound in the chloroform soluble fraction. The butanol soluble bitter rich fraction showed marginal activity. The results based on biochemical estimations have been expressed statistically and are additionally supported by histopathological examination of the liver of experimental rats and pentobarbitone induced sleep time studies in mice.

Animals↗
PubMed1999

Antihepatotoxic activity of Swertia chirata on paracetamol and galactosamine induced hepatotoxicity in rats.

The extracts of Swertia chirata were evaluated for antihepatotoxic activity using paracetamol and galactosamine models. The methanol extract of the whole plant was found active at a dose of 100 mg/kg i.p. On fractionating this extract into chloroform soluble and butanol soluble fractions, the activity was retained in the chloroform soluble fraction which was most active at a dose level of 25 mg/kg i.p. with overall protection of 81% and 78% against paracetamol and galactosamine, respectively. The butanol soluble fraction, rich in bitter secoiridoids, was devoid of significant activity. The protective effect observed against these two hepatotoxins which are different in their mechanisms of inducing hepatotoxicity, suggests broader and non-specific protection of the liver against these two toxins by non-bitter components of Swertia chirata.

Acetaminophen↗
PubMed1994

Detection and characterization of pangola stunt Fijivirus from Australia using cloned cDNA probes.

Four cDNA clones were generated from the genomic dsRNA of an Australian isolate of pangola stunt Fijivirus (PaSV). Each clone hybridized with nucleic acid extracts from PaSV infected plants but not healthy plants. Further, each clone hybridized with more than one segment of the PaSV dsRNA genome. One clone was used to demonstrate that homology existed between the Australian isolate of PaSV and a South American isolate of PaSV although the isolates differed in the sizes of the genomic dsRNAs and in the vector species. The clone also hybridized with some segments of the maize rough dwarf Fijivirus genome.

Australia↗
PubMed1994

Evidence for two groups of banana bunchy top virus isolates.

Banana bunchy top virus (BBTV) DNA component 1 from isolates from 10 different countries was cloned and sequenced and the sequences were aligned and compared. This analysis indicated two groups: the South Pacific group (isolates from Australia, Burundi, Egypt, Fiji, India, Tonga and Western Samoa) and the Asian group (isolates from the Philippines, Taiwan and Vietnam). The mean sequence difference within each group was 1.9 to 3.0% and between isolates from the two groups was approximately 10%, but some parts of the sequences differed more than others. However, the protein encoded by the major open reading frame, which is probably a replicase, differed by approximately 5%. The region from the beginning of the stem-loop sequence to the potential TATA box was identical in all isolates except for a two nucleotide change in the Western Samoan isolate and a single change in that of the NSW isolate. These results, together with other evidence, suggest that BBTV has spread to bananas after the initial movement of bananas from the Asian Pacific regions to Africa and the Americas.

Africa↗
PubMed1991

Stability and extractability of double-stranded RNA of pangola stunt and sugarcane Fiji disease viruses in dried plant tissues.

When leaves infected with pangola stunt virus (PaSV) were dried at 23, 37, 50, 70 or 105 degrees C, the dsRNA was stable and could be extracted after aerobic storage at room temperature for 1 month, although at 105 degrees C the amount obtained was reduced. The dsRNA was also recovered after leaves were freeze dried and stored in vacuo at room temperature for 6 months, or were dried and stored aerobically at room temperature for 10.5 months. dsRNA of sugarcane Fiji disease virus (FDV) was also stable when infected leaves were dried at 23, 37, 50 or 105 degrees C and stored aerobically for 3 months or for at least 6 months when infected leaves were dried at 70 degrees C. The unexpected high stability and extractability of both PaSV and FDV dsRNA when dried in leaves at low or high temperatures and stored at room temperature indicate that these, and probably other plant-infecting reoviruses, can be transported readily in desiccated host tissue between different countries for later extraction and comparison of their dsRNAs.

Desiccation↗