Search for chromosomal variations among gas-exposed persons in Bhopal

Summary A chromosomal survey using standard lymphocyte cultures employing different media and G-banding techniques was initiated in 1984. This study became particularly important following the tragic gaseous exposure of the population in Bhopal at midnight on 2 December 1984. We have been able to formulate a chromosomal profile for each person whom we have studied; during 1986–1988, 154 persons were examined twice. Among seemingly normal individuals, as many as 20% might possess some chromosomal abnormality; of these, 50% may develop, at a later date, some kind of pathological complication (such as tumours, recurrent abortion or transmission of defects to their offspring). The people exposed to methyl isocyanate have repeatedly shown Robertsonian translocations, mostly in acrocentric chromosomes 13 and 21. Other types of translocations have been studied among all exposed (53) and normal (101) persons; the involvement of chromosomes 5, 9, 11, 14 and 16 is statistically significant (P= <0.001). One of the major clinical symptoms is dyspnoea; we have estimated that almost all seriously dyspnoeic patients have developed at least two categories of chromosomal aberrations, one of which is Robertsonian translocation, in at least 10% metaphases. Our chromosomal survey will be of significance because we are able to identify people with chromosomal aberrations that might be correlated with future pathological consequences of the accident. The chromosomal load that can be sustained with an apparently normal phenotype can also be measured.     

Effect of bromocriptine,a dopamine receptor agonist,on the experimentally induced gastric ulcers in albino rats

The effect of bromocriptine, a dopamine receptor agonist, has been studied on the aspirin, phenylbutazone and reserpine induced gastric ulcers in rats. A single dose of bromocriptine 4 mg/kg s.c. produced a significant exacerbation of gastric ulcers induced by all the three ulcerogenic drugs, whereas in the same dose administered once daily for 5 consecutive days, it produced a marked protective effect in all the models. A review of the literature shows that different mechanisms may be involved in the opposite effects of acutely and chronically administered bromocriptine observed in this study. The study also points towards a role of dopamine in the pathogenesis of gastroduodenal ulceration.     

Phenolic acid effects on peanut growth and oil production

Plants of peanut (Arachis hypogaea L. var. PG No. 1) were given two foliar sprays of phenolic compounds (H-acid, 1, 2, 4-acid, resorcinol and RD-Brown) at 100 and 200 ppm, 35 and 50 days after sowing. In treated plants, shelling %, yield (kg/ha), number of gynophores per plant and number of pods per plant were significantly greater than in the control. Oil content of kernels also showed a significant increase with all the phenolic compounds applied. These compounds increased the linoleic acid concentration so improving nutritional quality. The number of gynophores was significantly correlated with the number of pods per plant and yield per hectare. The effect of phenolic compounds on growth and development was independent of their structural configuration.     

Ras complements the carboxyl terminus of v-Abl protein in lymphoid transformation.

Abelson murine leukemia virus (Ab-MLV) mutants expressing v-Abl proteins lacking the carboxyl terminus are compromised in the ability to transform lymphoid but not NIH 3T3 cells. This feature correlates with the presence of low levels of phosphotyrosine in lymphoid cells infected with carboxyl-terminal truncation mutants. In contrast, high levels of phosphotyrosine are observed in NIH 3T3 cells infected with wild-type and mutant Ab-MLV. Two downstream targets affected in lymphoid transformants are the GTPase-activating protein and GTPase-activating protein-associated protein p62, molecules which are heavily tyrosine phosphorylated in lymphoid cells transformed by wild-type Ab-MLV but not carboxyl-terminal truncation mutants of Ab-MLV. This difference suggested that signaling mediated via the Ras pathway may be compromised in lymphoid cells expressing the carboxyl-terminal truncation mutants. Consistent with this idea, expression of v-Ha-ras complemented these mutants in primary bone marrow transformation assays and increased transformation frequencies obtained with the Ab-MLV mutants 8- to 20-fold. These data suggest that a biologically important link exists between the carboxyl terminus of v-Abl protein and the Ras pathway. Signals transmitted via this connection may enhance those mediated via other regions of the v-Abl protein and facilitate transformation of primary, nonimmortalized cells such as pre-B lymphocytes.     

Identification of 3- and 4-phosphorylated phosphoinositides and inositol phosphates in stomatal guard cells

Components of the polyphosphoinositide signalling pathway have been identified in stomatal guard cells of Commelina communis L., one of the few plant systems shown unequivocally to be capable of responding to release of inositol 1,4,5-trisphosphate in the cytoplasm by increase in cytoplasmic Ca²⁺. 'Isolated' epidermal strips of C. communis (in which all cells other than guard cells have been killed by treatment at low pH) were radiolabelled with myo -[2n-³H]inositol or [³²P]orthophosphate for 17–18 h. The phosphoinositides and inositol phosphates were extracted. Phosphoinositides were deacylated and the head groups resolved by HPLC. The water-soluble products generated by mild periodate cleavage of HPLC-purified, deacylated lipid fractions were examined. The resulting biochemical analysis led to the identification of: PtdIns, PtdIns3 P , PtdIns4 P , PtdIns(3,4) P ₂ and PtdIns(4,5) P ₂. Thex inositol phosphates were resolved by HPLC. Preliminary analysis of HPLC-purified putative inositol phosphate fractions resulted in the identification of each inositol phosphate class, that is, Ins P , Ins P ₂, Ins P ₃, Ins P ₄, Ins P ₅ and Ins_P6. Many of these inositol phosphates occurred in different isomeric forms. The presence of 3-phosphorylated phosphoinositides suggests that they may have a role in signalling in stomatal guard cells.     

Mapping of the seed storage protein locus Sec-2 in rye

The segregation of the 75K gamma secalin locus (Sec-2) in combination with five interchanges (reciprocal translocations) and two marker genes was analyzed. The translocations involved chromosome arms 1RL, 1RS, 2RL, 2RS, 4RL, 5RL, 5RS, 6RL and 6RS. The gene loci were both on 2R, but the arm was not known. Although the Sec-2 locus was expected to be on chromosome 2RS, no linkage between Sec-2 and any of the markers was found. This is concluded to be the result of exceptionally frequent recombination between Sec-2 and the break point of one of the translocations, which is the only marker in 2RS.     

Using replicate observations in observer agreement studies with binary assessments.

By introducing replicate observations into observer agreement studies, one can obtain better measures of observer agreement than heretofore possible. New methodology based on the analysis of latent variables allows a separation of within- and between-observer variation for binary measures of assessment among pairs of observers. Maximum likelihood estimation and hypothesis testing are discussed. The methodology is illustrated using data on the assessment of dysplasia by pathologists.