Acute effects of GM1 ganglioside: reduction in both behavioral asymmetry and loss of Na+, K+-ATPase after nigrostriatal transection

GM1 ganglioside injections (i.p.) reduce amphetamine-induced asymmetric rotation in rats 48 h after a partial unilateral transection of the nigrostriatal pathway. We found that this reduction was maximal when rats received their first GM1 injection within 2 h after surgery. Rats injected 4-12 h after surgery, or rats only pretreated with GM1, showed no significant effect on rotation. Striatal membrane Na+,K+-ATPase in rats injected with GM1 0-2 h after hemitransection showed only a 10% loss in activity (versus the untransected hemisphere) as compared to control losses of 38%. The maintenance of membrane Na+,K+-ATPase activity in GM1-treated rats may be one mechanism by which a balance between hemispheres in striatal dopaminergic transmission is preserved, resulting in reduced asymmetric rotation. The observation that there is a critical postsurgical period when GM1 administration results in optimal functional recovery supports our hypothesis that gangliosides are exerting an acute effect on damaged CNS tissue. This acute effect is further evidenced by the reduced loss of membrane Na+,K+-ATPase following injury.

Mechanism of action of the platelet function inhibitor from Vipera russelli siamensis snake venom

Human platelet aggregation induced by ADP, adrenaline, collagen or thrombin was inhibited by the venom inhibitor. Heating reduced both its phospholipase A2 enzymatic and anti-aggregatory activities, although not in parallel. The inhibitor caused significant dose-related inhibitory effects on the clot retraction of rabbit platelet-rich plasma caused by thrombin, while platelet malondialdehyde formation stimulated by thrombin was not affected. Furthermore, the venom inhibitor increased basal cyclic AMP levels in platelets, while cyclic GMP content was slightly lowered, but not in a dose-dependent manner. In addition, microscopic study revealed that the cytoskeleton was disordered after treatment of platelets with the venom inhibitor. The platelets lost their discoid form, while the ultrastructural changes of platelet aggregation induced by ADP were blocked. It is concluded that increasing platelet cyclic AMP and the disorder of the cytoskeleton may be the mechanism of action of the venom inhibitor on platelet function.

Trends in morbidity and mortality for oesophageal cancer in Linxian County, 1959-1983

Data on morbidity and mortality from oesophageal cancer (EC) over the 25 years from 1959-1983 indicate that this malignancy has been the commonest cause of death in Linxian (LX) county during that period, accounting for 16% of deaths from all causes and 65% of deaths from cancer. Whereas incidence and mortality of EC were high but stable during this period, a decline in mortality has been noted recently in younger age groups, coinciding with an improvement in nutritional standards. Cohort analysis for the period 1879-1954 demonstrates mortality peaks among individuals born late in the last century and early in the present one. It also shows that a decline in mortality appears to have started among natives of the county born during the period 1935-1954.

Correlation of karyotype with patient sex and age in acute myeloid leukemia

Karyotypes were determined in 109 patients with acute myeloid leukemia. The proportions of patients with nonclonal chromosomal abnormalities, with numeric changes only, and with severe chromosomal aberrations were all found to increase to a statistically significant degree with patient age. Most patients in whom less than half of all cells were abnormal were elderly males. These results indicate that the cell karyotype was less stable in elderly patients than in younger patients. A higher frequency of nonclonal chromosomal changes was found in patients with clonal abnormalities compared with those without such abnormalities. Male patients tended to gain chromosomes and had more hyperdiploid abnormalities than female patients, who tended to lose chromosomes and had more hypodiploid abnormalities. This trend of chromosomal gain in males and loss in females mainly involved chromosomes similar in size to the sex chromosomes. Three female patients with trisomy 8 and one with 7q+ and t(8;21) showed an X chromosome twisted into a spiral shape. The results indicate that the initial karyotype effects the formation of some numeric changes. These findings are discussed in relation to possible secondary chromosomal changes and karyotypic instability.

A platelet function inhibitor purified from Vipera russelli siamensis (Smith) snake venom

By means of CM-Sephadex C-50 column chromatography and gel filtration on Sephadex G-75, a potent platelet function inhibitor was purified from Vipera russelli siamensis venom. It appeared as a single protein band on polyacrylamide gel electrophoresis in the presence or absence of SDS, and consists of 123 amino acid residues. Its NH2-terminal residue is serine. It showed the following characteristics: molecular weight, 13,800; isoelectric point, 10.4; LD50, 0.5 +/- 0.12 mg/kg (i.v.). The platelet inhibitor exhibited phospholipase A2 activity with a specific activity of 35 mumoles/min/mg. From 2 g of the venom, 70 mg of the purified inhibitor was obtained. Inhibition of human platelet aggregation induced by ADP or adrenaline was dose-dependent, with ID50 of 1.14 micrograms/ml or 0.37 microgram/ml, respectively. The platelet aggregation induced by thrombin or collagen was also inhibited and the inhibitory activity on platelet aggregation was heat stable (at 100 degrees C, 20 min) in an acidic medium (pH 5.8), while its phospholipase A2 activity was relatively heat labile under the same condition. The release of 3H-serotonin in platelets stimulated by ADP was also inhibited and this was positively correlated with inhibition of platelet aggregation induced by ADP (r = 0.998, P less than 0.002).

8;21 translocation in acute granulocytic leukaemia: cytological, cytochemical and clinical features

Thirty patients with the 8;21 translocation and three with closely related variants have been studied. Ages ranged from 3 to 64 years (mean 28.3). Thirty-one were entered into the MRC's 8th Acute Myeloid Leukaemia Trial. Twenty-nine (88%) achieved complete remission. Marrow smears from most patients showed granulocytic maturation (M2, FAB classification) with characteristic abnormalities, but at least six showed predominantly myeloblastic (M1) morphology. The blast cells were markedly heterogeneous with regard to size and nuclear cytoplasmic ratio. Typical staining patterns were observed in the blast cells using Sudan black B and diaminobenzidine peroxidase stains, and to a lesser extent with periodic acid-Schiff and chloroacetate esterase. Butyrate esterase was negative in all cases. Auer rods were present in the granulocyte precursors in 31 cases and in eosinophil precursors in two cases. In most cases the existence of the translocation was predicted from the cytological and cytochemical findings. Seven patients developed solid leukaemic deposits, principally in the mastoid cavities, orbital cavities or thoracic spine (extradural).

Groups of darkly stained chromosomes may be artifacts

Groups or conglomerations of darkly stained chromosomes (GDSC) observed in this study appeared to be artifacts as they were strictly technique dependent. Two methods of cell fixation were compared. In method I, fixative was added drop by drop to cell pellets and agitated continuously over a rotamixer. In method II, a few drops of fixative were added to hypotonic solution suspended with cells and mixed using a Pasteur pipette. In 11 patients with acute myeloid leukemia (AML) and in one patient with preleukemia studied using method I, no GDSC were found in the total of 325 metaphases examined. In 36 patients with AML, one with Klinefelter's syndrome and one with neutropenia studied using method II, GDSC were found in 18 patients. A further comparative study using different methods for cell fixation was performed in three patients. The frequency of cells with GDSC varied sharply with different methods used in two patients. In one patient the cells with GDSC were analyzed in detail. The number of darkly stained chromosomes in each cell was found to vary from 4 to 14 with a mean of 8.26 and D- and G-group chromosomes were preferentially involved.

A further study on quicker re-entry of chromosomally abnormal cells to active proliferation and preferential death of chromosomally normal cells during ageing of specimens in acute myeloid leukemia (AML)

Quicker re-entry of chromosomally abnormal cells to active proliferation under culture conditions was observed in cultured peripheral blood samples, old or fresh, but not in cultured bone marrow samples. In 10 patients with AML studied using peripheral blood, the mitotic index (MI) rose after 24 h in culture and reached a peak after 48 h in culture in AA patients (with all abnormal karyotypes); the MI rose after 24 h in culture and reached a peak after 48, 72 or 96 h in culture in AN patients (mixed normal and abnormal karyotypes); the MI remained at much lower level until after 72, 96 or 120 h of culture in NN patients (all normal karyotypes). The MI at 24 and 48 h of culture was significantly higher in AN and AA patients than in NN patients. A significantly increased frequency of chromosomally normal cells after prolonged culture was observed in one patient with t(8;21). The results of this study also suggest that chromosomally normal cells are more likely to die off than are abnormal ones during ageing of specimens.

Double minutes in acute myeloid leukemia

Five out of 110 patients with acute myeloid leukemia (AML) showed double minutes (DM) in cytogenetic preparations. DM were found to occur predominantly in elderly patients, and in erythroleukemia or acute myelomonocytic leukemia. The five patients were apparently divided into two groups according to the number of DM per cell. Patients with few sets of DM had exclusively complex karyotypes and a poor prognosis while patients with numerous DM had otherwise normal or nearly normal karyotypes and a good prognosis. Data on 11 previously reported cases of AML with DM were collected from the literature and consistent results were revealed except that several of the 11 patients were diagnosed as having acute myeloblastic leukemia (M1 and M2 in the FAB classification), which is apparently due to differences in diagnostic criteria. Therefore, numerous or few DM in a cell might relate to different entities. When the number of DM was small they might have resulted from breakdown of existing chromosomes.

Correlation between chromosomal pattern, cytological subtypes, response to therapy, and survival in acute myeloid leukaemia

Chromosomal karyotypes were determined with standard G-banding in 103 patients with acute myeloid leukaemia (AML). Abnormal clones were present in 52 (50.5%). Higher frequencies of abnormalities were observed in male than in female patients and in erythroleukaemia (EL) than in other subtypes of AML. Abnormalities were more frequent in myeloblastic (AMyL) than in myelomonocytic leukaemias (AMML) and mixtures of both normal and abnormal karyotypes were more common among elderly patients; these differences, though of marginal statistical significance, are consistent with previous reports. 9 of 10 cases with 5 or more aberrant chromosomes and 6 of 8 cases with unidentified marker chromosomes were either AMML or EL. Remission rates, median survivals and relative death rates were collated in 82 patients, in relation to the karyotype patterns NN (all normal), AN (mixed normal and abnormal) and AA (all abnormal). The differences between the groups did not reach statistical significance. Serial cytogenetic studies were performed in 10 patients. New karyotype changes emerged in only 1 of 6 relapses. 4 examples of t(8;21) and 2 of t(15;17) were found. 1 case of AMML showed trisomy 8 and double minute chromosomes. 1 case of EL showed 2 marker chromosomes with homogeneously staining regions.

A case of erythroleukaemia with homogeneously staining regions on chromosomes

A case of erythroleukaemia with homogeneously staining regions on chromosomes is described. The number of chromosomes in bone marrow cells varied from 41 to 46 with a mode of 43. A variety of structural and numerical chromosomal abnormalities was observed. Two marker chromosomes with homogeneously staining regions were found in all aneuploid cells examined. Intensive chemotherapy failed to induce a remission and the patient died 3.9 months after diagnosis. The relation of the homogeneously staining regions on chromosomes to the two courses of chemotherapy prior to cytogenetic study is discussed.

Cytogenetic study in acute myeloid leukaemia using peripheral blood samples sent by post

The patterns of chromosomal abnormalities in acute myeloid leukaemia (AML) revealed by study of peripheral blood specimens (group A) up to seven days old were comparable to the results from fresh bone marrow (group B). However, a decreasing proportion of cases providing enough metaphases for study, an increasing proportion of cases with chromosomal abnormalities, a decreasing ratio AN:AN + AA (see footnote Table 1) and a decreasing percentage of chromosomally normal cells in AN cases were found with ageing of specimens, which clearly demonstrates that cells with a normal karyotype were more likely to lose the capacity for dividing and die off than abnormal ones during ageing of specimens. Since the cells in older specimens were less active in division, a prolonged culture time was used. The different times for the cells from older specimens to re-enter active proliferation in culture conditions appeared to have some cytobiological significance. Three cases with t(8q-; 21q+) were present in group A but none in group B. Two cases of APL both showed a t(15q+; 17q-) and the breakpoints seemed to be at 15q24 and 17q22. One case showed trisomy 8 and double minute chromosomes. The remission rate in AN patients was lower than in AA or NN patients.

Derivation of an electron-transport rate equation, energy-conservation equations and a luminescence-flux equation of algal and plant photosynthesis

On the assumption that the photosynthetic electron-transport rate is sometimes limited on the water-splitting side of Q (the oxidized primary electron acceptor), and that Q reduction, as well as primary charge recombination, is not kinetically a monomolecular process, a rate equation, a luminescence-flux equation and several versions of energy-conservation equations are derived. The energy-conservation equations explain most, if not all, observed relationships between rate and fluorescence. In particular, by assuming that the limiting site on the water-splitting side of Q is uncoupler-sensitive, these equations explain the uncoupler-induced simultaneous stimulations of rate and fluorescence as well as inhibition of luminescence without additional assumption ad hoc for each individual phenomenon. A newly introduced parameter central to the derivation of these equations is the specific affinity between two electron carriers.

Salts and chloroplast fluorescence

Chlrorplast fluorescence was exicted by a weak measuring beam. A time-separated actinic light was used to modify the redox states of Q which in turn induced a change in the fluorescence yield. In salt-depleted chloroplasts, fluorescence saturated at a low actinic light intensity. CaCl2 increased the "variable" fluorescence as well as the rate of ferricyanide-Hill reaction. With Tris-washed chloroplasts, Photosystem II donor couple, phenylenediamine and ascorbate, did not increase the fluorescnece to a large extent without the presence of CaCl2. It is suggested that salt-depletion inactivates the Photosystem II reaction center of chloroplasts.