e19a2 BCR-ABL fusion transcript in typical chronic myeloid leukaemia: a report of two cases.

This report describes two patients with chronic myeloid leukaemia (CML): one of them developed accelerated phase CML and died 8 years after diagnosis and the other is at the chronic phase. Sequence analysis of reverse transcription-polymerase chain reaction products showed the presence of BCR-ABL fusion transcript e19a2. This finding suggests that CML carrying mu-BCR breakpoint may exhibit a clinical course similar to typical CML.

Glutathione S-transferase M1 and T1 null genotype frequency in chronic myeloid leukaemia.

Polymorphisms associated with genes coding for glutathione S-transferase enzymes are known to influence metabolism of different carcinogens and have been associated with incidence of various types of cancer. We have determined the GST M1 and GST T1 'null' genotype frequency in 81 patients with chronic myeloid leukaemia (CML) and 123 racially and geographically matched control individuals by multiplex polymerase chain reaction (PCR). GST M1 null genotype frequencies in CML and controls were 28.4% and 27.7%, respectively. GST T1 null genotype frequencies in CML and controls were 19.8% and 7.3%, respectively. The GST T1 null genotype frequency in CML patients is significantly different from that in controls (odds ratio (OR) 3.12, 95% confidence interval (CI) 1.3-7.45, P=0.008).

Changing scenario of transfusion-related viral infections.

OBJECTIVE: To study the changing incidence of blood transfusion-related viral infections consequent to compulsory screening of blood and greater awareness of the problem, over the last five years. METHODS: This is a cross-sectional study carried out at Medical College, Calcutta. Three groups each consisting of 100 subjects were selected for this study. Group A comprised multiple transfused patients who have also received transfusion before 1995. Group B comprised patients who had received transfusions only since 1995. Group C comprised of control patients who have never been transfused. The incidence of HBsAg +ve, anti-HCV +ve and HIV +ve cases were calculated and expressed as percentages and compared using the chi square test. RESULTS: The incidences of HBsAg +ve and anti-HCV +ve cases in the three groups were 20% and 16% in Group A, 7% and 6% in Group B and 4% and 2% in Group C. The difference between Group A and Group B were statistically significant. CONCLUSION: The incidence of HBsAg and anti-HCV positive cases among the multi-transfused has decreased over the last five years.

Solitary plasmacytoma of the skull bone.

Solitary plasmacytoma of the bone is an uncommon variety of plasma cell tumour. Here an interesting case of solitary plasmacytoma of the skull bone, which is extremely rare, is being reported.

Structural organisations of hemoglobin and myoglobin influence their binding behaviour with phenothiazines.

Binding modalities of chlorpromazine and trifluoperazine, two widely used antipsychotic phenothiazine drugs with hemoglobin and myoglobin have been studied to understand how the quaternary, tertiary and secondary structural organisations of the proteins regulate the binding process. NaCl-induced alteration in the quaternary structure of hemoglobin influences its binding modality with phenothiazines. Minor alterations in the tertiary structure of thermally denatured myoglobin (denaturation temperature ranging between 30-70 degrees C) do not affect its affinity and the modality of binding with the drugs, but alterations in the secondary structure of the protein denatured at temperatures between 70-80 degrees C influence its binding.

Trifluoperazine is more effective than chlorpromazine in releasing oxygen from haemoglobin and myoglobin.

The extent of oxygen release from two heme proteins, haemoglobin and myoglobin have been studied in the presence of trifluoperazine and chlorpromazine (5-1000 microM). At a molar ratio (drug:protein) of 1.5, the release of oxygen from haemoglobin was 4 and 15% in the presence of chlorpromazine and trifluoperazine respectively, while from myoglobin the corresponding values were 20 and 40%. The findings were attributed to the greater extent of local conformational change around tryptophan moieties of each of the proteins induced by trifluoperazine.

Interaction of chlorpromazine with myoglobin and hemoglobin. A comparative study.

The mode and nature of the binding of chlorpromazine (CPZ), a psychotropic drug, with myoglobin, a monomeric muscle protein, were studied spectrofluorometrically and the results compared with those from the binding of CPZ to hemoglobin, a tetrameric allosteric protein from red blood cells (RBC). CPZ interacted with myoglobin in a non-cooperative mode, with a binding constant of 8.4 x 10(3) M-1 in 0.145 M NaCl, pH 6.8, whereas in the case of hemoglobin this interaction was found to be positively cooperative with a binding constant of 4.2 x 10(3) M-1. The interaction of CPZ with myoglobin was not influenced by the NaCl molarity of the solution, whereas CPZ interaction with hemoglobin significantly decreased with increasing NaCl molarity, indicating that CPZ-hemoglobin binding is mostly electrostatic in nature, whereas that of the CPZ-myoglobin complex is of a non-electrostatic type. Thermodynamic analysis revealed that binding of CPZ to hemoglobin was exothermic (delta H degrees = -2.65 kcal/mol), whereas binding to myoglobin was endothermic (delta H degrees = + 1.39 kcal/mol) with a high entropic contribution (delta S degrees = +23 cal/degree/mol), suggesting that CPZ binding to myoglobin is hydrophobic in nature. Such contrasting binding features of this drug have been discussed in the light of a typical subunit interaction property present and absent in hemoglobin and myoglobin, respectively.

Chlorpromazine induced aggregation of normal human hemoglobin. Electron microscopic evidence.

Normal human hemoglobin exceeding a certain minimum concentration (called critical aggregation concentration) undergoes aggregation in presence of the psychotherapeutic drug chlorpromazine (CPZ). The critical aggregation concentration decreases with the increase of CPZ concentration. Electron micrographs of CPZ-treated hemoglobin clearly indicate that the aggregates of hemoglobin are in filamentous form of average width 75 +/- 8 A. A possible mechanism for such aggregation has been discussed.

True hermaphroditism: a report of two cases.

Two cases with true hermaphroditism are described. A 2 year old child presented with ambiguous genitalia, and had bilateral ovotestis in the labioscrotal folds. A 20 year old boy presented with grade V gynaecomastia and periodical bleeding as well as seminal discharge after phallic stimulation; he had right sided ovotestis, normal size uterus, left ovary and hypoplastic fallopian tubes. Male gender was assigned to both. Cytogenetically both were 46XX. Gonadectomy was done in both the cases. Bilateral mastectomy and hysterectomy was done in the second case.

Studies on the interaction of chlorpromazine with haemoglobin.

The interaction of chlorpromazine (CPZ), a widely used antipsychotic tranquillizer, with the allosteric protein haemoglobin, has been studied by different methods. From r versus Cf plot obtained by an equilibrium dialysis experiment, the maximum value of r was found to be 6.8 at 0.15 M NaCl. Binding parameters, namely the affinity constant K and the degree of cooperativity nH, were determined from the Hill plot. Circular dichroism studies indicate a conformation change of haemoglobin in the presence of CPZ. Oxygen has been found to be released from haemoglobin with the progressive addition of CPZ. The extent of the release of oxygen depends on the stoichiometric ratio of CPZ: haemoglobin (D/P). The possible nature of the binding site of the protein has been discussed on the basis of the information obtained from fluorescence measurements.

Interaction of chlorpromazine with hemoglobin.

Binding of chlorpromazine (CPZ), a widely used antidepressant tranquilizer, with hemoglobin has been studied by equilibrium dialysis method. r/Cf versus r plot was typically concave downwards revealing the positive cooperative nature of binding. Binding parameters, namely the affinity constant (K) and the degree of cooperativity (nH) were determined from the Hill plot. Oxygen was found to be released gradually from hemoglobin with gradual addition of CPZ, the extent of oxygen release depending on the stoichiometric ratio of CPZ: hemoglobin (D/P).

Evidence for cooperative binding of chlorpromazine with hemoglobin: equilibrium dialysis, fluorescence quenching and oxygen release study.

Binding of chlorpromazine (CPZ) with human hemoglobin has been studied by equilibrium dialysis and fluorescence quenching. Results of equilibrium dialysis experiment when analysed by Hill plot revealed that the binding was positively cooperative with overall affinity constant K = 3.8 x 10(3) M-1. CPZ quenched the fluorescence of hemoglobin and the analysis of the quenching data by Stern-Volmer equation indicated two types of quenching process, namely, dynamic and static quenching. Dynamic quenching constant was measured from the decay of fluorescent life time of tryptophans of hemoglobin in presence of CPZ. Static quenching constant concerned with the ground state complex formation between CPZ and hemoglobin was found to be 5 x 10(3) M-1. Almost all the tryptophans of hemoglobin were found to be accessible for CPZ to interact with. Oxygen was found to be released when CPZ was added to hemoglobin. Extent of release of oxygen depends on the D/P ratio of CPZ(D): hemoglobin(P).

Cooperative binding of chlorpromazine with hemoglobin.

The binding of chlorpromazine (CPZ), an widely used tranquilizer, with hemoglobin (Hb) at pH 6.5 has been investigated by means of spectrophotometry, circular dichroism (CD), and equilibrium dialysis. In CD spectra Hb treated with CPZ exhibited a blue shift of 5 nm in the visible wavelength range. The positively cooperative nature of binding was revealed by equilibrium dialysis experiments. The basic parameters, namely, the cooperative binding constant (K), the degree of cooperativity (q), and the number of amino acids (n) occupied by one CPZ molecule were evaluated from spectrophotometric and dialysis experiments and found to be sensitive to NaCl concentration, suggesting the electrostatic nature of the binding process.

Differential survival and chloramphenicol-insensitive error-prone repair of hydroxylamine-inactivated phi X174 bacteriophage mutants.

Features of inactivation, repair and concomitant mutagenesis of hydroxylamine-treated phi X174 bacteriophages are reported here. (1) For reasons unknown, the nonsense phage mutants tested here were far more sensitive to hydroxylamine than the wild-type phage. In contrast, the sensitivities of these same phi X174 mutants to UV-irradiation are indistinguishable. (2) Hydroxylamine-treated amber phages mutated to ochre but not to wild-type particles, i.e., G leads to A transition events were recovered. (3) The repair of phi X174 phages from hydroxylamine-induced damage was error-prone, but unlike UV damage, did not require protein synthesis de novo. Possible mechanisms of these novel features are discussed.

Ultraviolet, photodynamic and thermal inactivation of mycoplasmaviruses.

The ultraviolet light, photodynamic, and thermal inactivation parameters have been measured for the three groups of mycoplasmaviruses. The differences in these parameters for the three virus groups reflect differences in virion structure and in genome size and structure.

Gliding mycoplasmas are inhibited by cytochalasin B and contain a polymerizable protein fraction.

Studies are presented on the effect of cytochalasin B (CB) on the growth of five Mycoplasma species, three Acholeplasma species, and one Spiroplasma species. The three gliding mycoplasma species (M gallisepticum, M pneumoniae and M pulmonis are the only mycoplasmas inhibited by CB. These are the only prokaryotes reported to be inhibited by CB. This suggested that these three mycoplasmas might have some sort of cytoskeletal structure. A protein fraction has been isolated from M gallisepticum which polymerizes in 0.6 M KCl and depolymerizes when KCl is removed. This fraction contains a major 58,000-dalton protein, a 46,000-dalton protein, and a minor 87,000-dalton protein.

Photodynamic inactivation and its repair in mycoplasmas.

Photodynamic inactivation is the loss in viability observed when organic dye-treated cells are exposed to visible light and molecular oxygen. The photodynamic inactivation of mycoplasmas, the smallest free living cells, has been studied. Depending on the extent of inactivation in Acholeplasma laidlawii, photodynamic induced damage can be repaired if the irradiated cells are incubated in the dark in buffer. Analysis of the DNA of these cells shows that photodynamic inactivation induces single strand breaks which can be repaired during liquid holding. To examine possible damage to the cell membrane, glucose uptake was studied as a permeability measure. Neither acriflavine nor photodynamic inactivation had any measurable effect on membrane permeability.