Aristololactam-beta-D-glucoside. A new DNA binding monofunctional intercalating alkaloid

The binding of aristololactam-beta-D-glucoside to DNA is characterized by hypochromism and bathochromism in the absorption band, quenching of the fluorescence intensity, increase in the positive and negative ellipticity of DNA, enhancement of thermal transition temperature, sign and magnitude of thermodynamic parameters, increase of the contour length of sonicated rod-like DNA and induction of the unwinding-rewinding process of covalently closed superhelical DNA. Binding parameters determined from absorbance and fluorescence titration by Scatchard analysis, according to an excluded-site model, indicate a very high affinity towards DNA. The binding of the alkaloid is an exothermic process with Gibbs free energy of -7.4 kcal/mol, van't Hoff enthalpy of -13.8 kcal/mol and entropy of -21.5 cal/degree/mol at 25 degrees. On the basis of these observations it is concluded that aristololactam-beta-D-glucoside binds to DNA by a mechanism of intercalation.

Copper (II) induced radiosensitization of thymine

An aqueous solution of thymine (2 x 10(-3) M, pH 5.6) was irradiated with 60Co gamma-rays in the absence and in the presence of CuSO4 (5 x 10(-4) M) under different conditions. In argon and N2O saturated solutions, the presence of CuSO4 increased the radiosensitivity of thymine to a greater extent, while the product distribution was changed. Thus in the presence of CuSO4 the formation of dimeric products was prevented and the yields of cis-thymine glycol and 5-hydroxymethyl uracil were greatly increased. The sensitized degradation was suggested to be due to the oxidation of the transient hydroxyl adducts of thymine by copper ions.

Structural rearrangement of the retinoblastoma gene in human breast carcinoma

Structural changes of the human retinoblastoma gene have been demonstrated previously in retinoblastoma and some clinically related tumors including osteosarcoma. Structural aberrations of the retinoblastoma locus (RB1) were observed in 25% of breast tumor cell lines studied and 7% of the primary tumors. These changes include homozygous internal deletions and total deletion of RB1; a duplication of an exon was observed in one of the cell lines. In all cases, structural changes either resulted in the absence or truncation of the RB1 transcript. No obvious defect in RB1 was detected by DNA blot analysis in primary tumors or cell lines from Wilms' tumor, cervical carcinoma, or hepatoma. These results further support the concept that the human RB1 gene has pleiotropic effects on specific types of cancer.

Reed-Sternberg cells in Hodgkin's cell lines HDLM, L-428, and KM-H2 are not actively replicating: lack of bromodeoxyuridine uptake by multinuclear cells in culture

We compared the proliferation of mononuclear and multinuclear cells in four Hodgkin's cell lines, HDLM-1, HDLM-1d, L-428, and KM-H2, by examining their capacity to incorporate bromodeoxyuridine (BrdUrd) into nuclei. Approximately 5% of all cells in HDLM-1 cultures had two or more nuclei, a characteristic of Reed-Sternberg (RS) cells. Unlike mononuclear Hodgkin's (H) cells, these RS cells exhibited no uptake, or only minimal uptake of BrdUrd, suggesting that they did not replicate actively. Cytogenetic study showed that 25% of the HDLM-1 cells contained a tetraploid (4X) set of chromosomes with a characteristic two-peak distribution. Following treatment of HDLM-1 cells with phorbol ester, the percentages of 4X cells and RS cells increased to 50% and 12%, respectively. This increase in RS cells was not likely to be due to cell fusion as shown by the absence of hybridization of BrdUrd-positive and -negative nuclei. Phorbol ester has a short-term effect of blocking the exit of cells from G1 into S phase, but no effect on the transition from S phase to G2/M phase. The block is more prominent in 2X cells than in 4X cells, which may explain the increase in percentage of 4X cells in phorbol ester-treated cultures. In addition, phorbol ester induced the differentiation of H-RS cells, which was accompanied by loss of the marker HeFi-1 from the cell surface. Approximately one third of the RS cells did not express HeFi-1, or expressed only minimal amounts. The findings led us to the following conclusions: (1) The 4X cells probably are formed from 2X H cells as a result of disturbed cytokinesis, but not a cell fusion. (2) A considerable number of 4X cells were H cells, because the number of 4X cells consistently exceeded that of RS cells. (3) Since mitotic figures are extremely rare in RS cells and these cells did not show active BrdUrd uptake, the increased number of RS cells must also be a consequence of disturbed cytokinesis of H cells or a result of nuclear transformation (twisting, convolution, or separation of the nucleus) in H cells. (4) Most RS cells lose their proliferating capacity and some RS cells may undergo further differentiation. Uptake of BrdUrd and phorbol ester induction were also studied on the other three H-RS cell lines, HDLM-1d, L-428, and KM-H2, with results similar to those for HDLM-1.

Influence of some dietary chemopreventive agents on the expression of functional differentiation of the mouse mammary gland in vitro

The purpose of the present studies was to determine the influence of the chemopreventive agents selenium, 4-(hydroxyphenyl)-retinamide (4-HPR) and beta-carotene, on functional differentiation (lactogenesis) of the mouse mammary gland cells. The hormone-induced expression of the milk-protein genes, beta-casein, epsilon-casein and the whey acidic protein (WAP) was used as molecular marker of differentiation of the mammary cells in organ culture medium containing insulin, prolactin, aldosterone and hydrocortisone. Quantitative determination of the cellular concentration of the respective mRNA was ascertained by molecular hybridization of RNA to the specific cloned cDNA probes using both the solution and the filter hybridization methods. Selenium at 100 nm concentration caused a pronounced inhibition of accumulation of the respective mRNAs. The retinoid, 4-HPR, also caused a dose-dependent inhibition of expression of these mRNA sequences. In contrast, concentrations of the 3 mRNAs in beta-carotene-treated glands remained similar to those observed in glands cultured in medium containing the hormones and hexane (the latter being the solvent for beta-carotene). The significant antagonistic action of selenium and 4-HPR, however, was reversible after removal of the chemicals from the culture medium. Thus, among the 3 chemicals tested, selenium and retinoid can cause an adverse effect on functional differentiation (lactogenesis) of the mammary cells. This inhibitory effect, however, was reversible. beta-Carotene, on the other hand, caused no apparent antagonistic effect on expression of the milk-protein genes in the isolated whole mammary organ in culture.

Hematological changes produced by lindane (gamma-HCH) in six species of birds

Hematological changes were studied after oral administration of lindane (gamma-hexachlorocyclohexane) at 5 mg/kg body weight twice in 1 week in 6 species of agriculturally important birds: house sparrow, baya weaver bird, common myna, rose-ringed parakeet, blue rock pigeon and domestic duck. Lindane induced anemia in the birds as judged by reduced RBC count, hematocrit and hemoglobin content with corresponding changes in MCV, MCH and MCHC. Bleeding and clotting time were markedly prolonged. Splenic cell counts were decreased with marginal increase of splenic weight in most of the lindane fed birds. Total leucocyte counts were increased while the differential counts of WBC show marked heterophilia and eosinophilia with a decrease in monocyte, lymphocyte and basophil numbers. Domestic duck appears to be somewhat resistant compared to the wild birds studied. Besides anemia the results suggest both immunosuppression and stress effects and indicate that early hematological changes induced by lindane may serve as an initial warning for pesticide toxicity.

Nucleic acids in the spermatozoa of pure and strain crosses of White Leghorn cockerels

Nucleic acids (DNA and RNA) were estimated in the spermatozoa of three pure strains (M, N and P) and three strain crosses (N X P, M X N and P X M) of White Leghorn cockerels. The average DNA content was 2.31 +/- 0.06 X 10(-9)mg/sperm. Most was found in the P X M strain cross and least in the P strain. The DNA content of the P strain was significantly lower than that in the other strains and it also had the lowest fertility and hatchability of all the strains. The average RNA content in poultry spermatozoa was 0.0522 +/- 0.0038 X 10(-9)mg/sperm. Again, most RNA was found in the P X M strain cross and least in the P strain. The P X M strain cross had a significantly higher RNA content than the rest of the strains. Thus, the P X M strain contained the most DNA and RNA whereas the P strain had least.

Density of Culex vishnui and appearance of JE antibody in sentinel chicks and wild birds in relation to Japanese encephalitis cases

In the District of Burdwan, a rural area of West Bengal State, India, Japanese encephalitis (JE) virus is endemic. In one village a longitudinal survey was conducted in order to find out whether associations could be established between the density of the vector mosquito Culex vishnui in two types of resting places, the incidence of infections in sentinel chicks exposed at monthly intervals, the prevalence of antibodies in wild birds and the occurrence of clinical infections in the human population. The experiment lasted from August 1981 till August 1982. Meteorologically a summer season (March-June), a rainy season (July-October) and a winter season (November-February) are distinguished. In the sentinel chicks infections were observed in all three seasons; in wild birds antibodies were prevalent throughout the year; these observations suggest perennial transmission of the virus in its maintenance cycle. Human infections were observed periodically with, in August 1982, a pronounced peak; this may point to fluctuations in the level of circulation of the virus in its maintenance cycle and spillover to the human population at times of peak circulation. The peaks may be related to the influx of young non-immune birds and newborn mammals into the animal population in summer. Further studies, including virus isolation attempts from mosquitoes and nestling birds, are required to prove this hypothesis.

Estradiol modulation of pineal gland activity in the wild bandicoot rat, Bandicota bengalensis

In the present study, the effect of estradiol dipropionate on the cytology and mitotic activity of the pineal gland was evaluated in adult ovariectomized and juvenile bandicoot rats, Bandicota bengalensis. Estradiol treatment for 5 days inhibited the ovariectomy-induced hypertrophy of the pineal gland, and increased the nuclear diameters of pinealocytes in juvenile males while having no effect on the pineal cytology of juvenile females. Estradiol injection induced mitosis in the pinealocytes of adult ovariectomized and juvenile bandicoot rats. Thus, estradiol exhibited a dual action (stimulatory and inhibitory) on the pineal gland of this wild rat.

The reduction of root colonization by mycorrhizal fungi by mycophagous amoebae

Two mycophagous amoebae, Saccamoeba sp. and Gephyramoeba sp., reduced the colonization of pine roots in soil by the ectomycorrhizal fungus, Rhizopogon luteolus, when added at the same time as the fungus or 2 weeks later. Another mycophagous amoeba, an unidentified leptomyxid, was unable to do so. When seedlings were grown in sterilized soil amended with different population levels of Saccamoeba, 42 and 85 amoebae g soil−1 had no effect but large reductions in root colonization by R. luteolus occurred when 430 and 860 amoebae g soil−1 were added. After 4 weeks, however, the protozoa population increased to a similarly high level in all treatments irrespective of the numbers added initially. Our results indicate that protozoa can have a large effect on the establishment of inoculated symbiotic fungi and could markedly affect the microbial composition of the rhizosphere.

Mitogenic action of prolactin on the pancreatic islet cells in the chick

A histological investigation was made to elucidate whether mammalian (ovine) prolactin can induce mitotic activity in pancreatic islet cell (in splenic lobe) of chicks. Prolactin treatment in different dosages (total dosage: 15, 50 and 100 IU per bird in 10 days) increased the mitotic frequency and also caused hypertrophy in the AF-positive cells of the B-islets in the splenic lobe. The increase in mitotic frequency was uniform for all doses applied. It is suggested that prolactin has a mitogenic action on the pancreatic islet cells of male chicks and that action is possibly not dose-dependent.

Cytophysiological responses of the pineal gland to intermale aggression in a wild rat

Intermale aggression by pairing bandicoot rats (Bandicota bengalensis) in their home cage, continuously for three hours, stimulated the pineal gland activity, cytologically measured by decreasing cell population density and increasing nuclear size of the pinealocytes, in the socially subordinate animals. The pineal gland of the dominant animal was not perceptibly affected by aggression. It is suggested that during aggression, the subordinate rats perhaps suffered from psychosocial stress that might have caused hyperactivity of their pineal gland.

Cytophysiological response of the pineal gland to long-term administration of norethisterone (a progestogen-only contraceptive) in rats

Chronic administration of norethisterone for 75 days caused a marked inhibition of the pineal gland activity of cycling albino rats. In addition to a decrease in the nuclear diameter, possibly the cell size also decreased. The progestin, however, failed to induce mitosis in this gland. It is suggested that prolonged administration of norethisterone exerts untoward effects on the pineal gland function in adult female albino rats.

Studies on dimensional characteristics of spermatozoa in pure and strain crosses of White Leghorn cockerels

Sperm head dimensional characteristics were evaluated in three pure strains (M, N, and P) and three strain crosses (N x P, M x N, and P x M) of White Leghorn cockerels. A total of 120 collections from 24 cockerels were taken. The average sperm head length recorded was 14.58 +/- .09 mu, with an average maximum value of 15.29 +/- .19 mu for spermatozoa from the P x M strain cockerels. The average sperm breadth was found to be .722 +/- .005 mu. Maximum values were found for spermatozoa from the M x N strain cockerels that averaged .735 +/- .004 mu. There was a significant difference (P less than .01) between strains for sperm head length. The P x M strain had a significantly longer sperm head length than the other strains. This may be associated with heterosis. There were no significant differences among strains for sperm head breadth. The mean sperm head area was recorded to be 10.61 +/- .08 mu 2. Maximum sperm head area was observed in semen from P x M strain cockerels (11.03 +/- .15 mu 2). The average sperm head shape was found to be 20.14 +/- .22. There were significant differences (P less than .01) among strains for sperm head area and sperm head shape. The repeatability estimates for all the dimensional characteristics showed that they are highly repeatable traits, indicating that additive gene action is playing an important role in the expression of these traits.

The chemistry of pyrrolic compounds. LII. The preferred pathway of electron delocalization in metalloporphyrins

Measurement of the proton coupling constant in the allylic unit, CH3-C=C-H, of the zinc(II), nickel(II) and magnesium(II) chelates of the deuteroporphyrin isomer (3a) points in each case to the double bond of this system having a significantly diminished bond order. Similar data have been obtained for the dication derivative of (3a). These findings are in accord with the view that the π-electron delocalization pathway in porphyrin dications and metalloporphyrins involves the periphery of the molecule as was previously shown for the metal-free porphyrin. New synthetic approaches to the porphyrin (3a) have been studied.

Prolactin induced mitotic activity in the anterior pituitary gland of the chick

The current investigation was undertaken to study whether mammalian prolactin can induce mitotic activity in the anterior pituitary gland in chicks. It was found that intramuscular injections of ovine prolactin (1.5 i.u. and 10 i.u. each daily per bird for 10 days) significantly increased mitotic frequency in the adenohypophysis of juvenile cockerels. It is suggested that ovine prolactin has a mitogenic action on the adenohypophysis of the male chicks and that the reaction may be dose-dependent.