Quantitative exfoliative oral cytology in iron-deficiency and megaloblastic anemia

A study was undertaken to ascertain if there were any morphometric or morphologic changes in exfoliated oral squames in either iron-deficiency or vitamin B12-deficiency states. The results revealed a significant (P less than .05) increase in nuclear area and a significant alteration in nuclear/cytoplasmic ratio in vitamin B12 deficiency; both returned to normal following replacement therapy. No changes were seen with iron deficiency anemia or non-vitamin B12 megaloblastic anemia. Ultrastructurally, the surface morphology showed similar features in all groups, with the plasma membrane forming complex folds (microplications) in three patterns: branching, parallel and network. The microplication widths and interplication distances were remarkably constant in both control and study groups, regardless of pattern.     

Effect of N,P, and K on root yield and nutrient levels in the leaves and roots of rutabagas grown in a greenhouse

Summary Experiments were conducted to determine the influence of N, P, and K and of the NP and NK interactions on root yields and tissue concentrations of N, P, and K of rutabagas grown on a sandy loam soil under greenhouse conditions. Root yields were increased by applications of N and K but not by added P. The yield response to N was dependent on K supply. The highest dry matter content in roots was associated with the lowest rates of N and K and the lowest root yields. The N content of tissue at the early vegetative stage increased with increasing rates of N and decreased with increasing rates of P and K. The N content of root tissue at harvest increased at the highest rates of N but was unaffected by rates of P and K. The P and K content of root tissue increased with increasing rates of P and K, respectively. The levels of nutrients in early vegetative tissue associated with optimum yields were about 2.6, 0.24, and 2.0% for N, P, and K, respectively. The corresponding values in the leaf tissue at harvest were about 1.2, 0.12, and 1.5% N, P, and K, respectively. Contribution No.222.     

Selective esterification of 1,6-anhydrohexopyranoses: The possible role of intramolecular hydrogen-bonding

Selective esterification reactions of 1,6-anhydro-3-deoxy-β-D-xylo-hexopyranose(1), 1,6-anhydro-β-D-glucopyranose (7), and several derivatives of 7, were conducted with an acid chloride or acid anhydride in pyridine. Reaction of 1 with p-toluenesulfonyl chloride and with benzoyl chloride gave 70 and 63%, respectively, of the 2-esters. The 2-methyl and 2-benzyl ethers of 7, both having strongly hydrogen-bonded C-4 hydroxyl group, reacted with p-toluenesulfonyl chloride to yield the 4-monosulfonates (71 and 74%, respectively). Esterification of the 2-methyl ether and 2-p-toluenesulfonate of 7 with p-toluenesulfonic anhydride instead of with p-toluenesulfonyl chloride led to increased yields of the 4-p-toluenesulfonates after a shorter reaction-time.     

Sensitive rapid detection method for viable bacterial cells

A rapid sensitive method for the detection of viable bacterial cells is described in which P³² as inorganic orthophosphate is used to label the cells. Factors affecting the uptake of P³² by cells as well as the sensitivity of the method have been explored with suspensions of Aerobacter aerogenes. The uptake of P³²O₄ is dependent on several factors. Of various incubation media tested, one composed of 0.005 m KCl, 0.002 m MgSO₄ and 10 mg/ml of glucose was found to best stimulate the uptake of the tracer. Incubation time and temperature and level of isotope and of unlabeled P also affected uptake. Labeled cells were collected on a membrane filter for measurement of radioactivity. Under optimal conditions, as few as 23 viable cells per milliliter were detected in 1 hr with 95% confidence.     

The importance of intercalation in the covalent binding of benzo(a)pyrene diol epoxide to DNA

The primary mode of non-covalent interaction of the strong carcinogen, benzo(a)pyrene diol epoxide, with DNA is through intercalation. It has variously been suggested that intercalative complexes may be prerequisite for either covalent binding or DNA-catalysed hydrolysis of the epoxide or both. Geacintov [Geacintov, N. E. (1986). Carcinogenesis 7, 589.] has recently argued that intercalation is important in covalent binding and presented theoretical constructs consistent with this proposal. A more general theoretical model is presented here which includes the possibilities that either catalysis of hydrolysis or covalent binding of benzo(a)pyrene diol epoxide DNA can occur (a) in an intercalation complex, or (b) without formation of a detectable, physically bound complex. It is shown that a variety of possible mechanisms formulated under this general theory lead to equations for overall reaction rates and covalent binding fractions which are all of the same form with respect to DNA concentration dependence. A consequence of this is that experimental studies of the dependence of hydrolysis rates and covalent binding fractions on DNA concentration do not distinguish between the various possible mechanisms. These findings are discussed in relation to the interactions of benzo(a)pyrene diol epoxide with chromatin in cells.     

Loss of Rb activates both p53-dependent and independent cell death pathways in the developing mouse nervous system.

Extensive apoptosis occurs in the nervous system of mouse embryos homozygous mutant for a targeted disruption of the retinoblastoma (Rb) gene. This cell death is present in both the central (CNS) and peripheral nervous systems (PNS) and is associated with abnormal S phase entry of normally post-mitotic neurons. Aberrant proliferation in the CNS correlates with increased free E2F DNA binding activity and increased expression of cyclin E, an E2F target gene and critical cell cycle regulator. Cell death in the CNS is accompanied by increased levels of the p53 tumor suppressor gene product and increased expression of the p53 target gene, p21Waf-1/Cip-1. However, induction of p53 is not observed in the PNS of Rb-mutant embryos, nor does loss of p53 function inhibit cell death in the PNS. Surprisingly, p21Waf-1/Cip-1 is induced in the sensory ganglia of Rb-mutant embryos in a p53-independent manner. Although loss of p53 gene function prevents cell death in the CNS of Rb-mutant embryos, it does not restore normal proliferative control.     

Critical importance of microsome concentration in mutagenesis assay with V79 Chinese hamster cells.

For optimum mutagensis in V79 Chinese hamster cells, the amount of liver postmitochondrial fraction in the assay was found to be of critical importance, depending on the chemicals being tested. Benzo[a]pyrene (BP) required lower (1-5%) concentrations of the liver 15 000 X g supernatant (S15) from methylcholanthrene pretreated rats for a maximum induction of cytotoxicity and mutagenicity, as determined by 8-azaguanine- and ouabain-resistance. A sharp peak of mutagenicity and cytotoxicity was induced by 7,8-dihydroxy-7,8-dihydrobenzo[a]pyrene (7,8-diol BP) at a concentration of 1% of the S15 fraction. Little or no response was induced by these compounds with the S15 concentrations of more than 10%. Similarly, aflatoxin B1 induced a sharp peak of mutagenicity and cytotoxicity at a concentration of 2% of the liver S15 fraction from Aroclor-pretreated rats. Under the same condition, non-carcinogenic aflatoxin G2 did not induce cytotoxicity and mutagenicity. Analysis of BP metabolites by high-pressure liquid chromatography indicates that with the 30% S15 fraction, more than 80% of BP was metabolized during the first 15 min, while with the 2% S15 fraction, 7,8-diol BP increased continuously throughout the 120-min incubation period, suggesting a strong metabolic competition to rapidly remove BP and 7,8-diol BP with a high concentration of the S15. In contrast with these compounds, N-nitrosodimethylamine induced mutagenicity and cytotoxicity which increased linearly in proportion to the increasing amount of the S15 fraction from phenobarbitone- and Aroclor-pretreated rats. Various nitrosamines with different lipophilicity were examined at a high (30%) and low (2%) concentration of the S15 fraction from Aroclor-pretreated rats, in which ratios of mutation frequencies at 30% and 2% correlated inversely with lipophilicity of the compound. This result suggests that the lipid solubility of test compounds may be one factor which determines the concentration of post-mitochondrial supernatant for optimum mutagenesis.