Evaluation of vitamin D3 metabolites in Callithrix jacchus (common marmoset)

Vitamin D₃ (cholecalciferol) is endogenously produced in the skin of primates when exposed to the appropriate wavelengths of ultraviolet light (UV-B). Common marmosets (Callithrix jacchus) maintained indoors require dietary provision of vitamin D₃ due to lack of sunlight exposure. The minimum dietary vitamin D₃ requirement and the maximum amount of vitamin D₃ that can be metabolized by marmosets is unknown. Observations of metabolic bone disease and gastrointestinal malabsorption have led to wide variation in dietary vitamin D₃ provision amongst research institutions, with resulting variation in circulating 25-hydroxyvitamin D₃ (25(OH)D₃), the accepted marker for vitamin D sufficiency/deficiency. Multiple studies have reported serum 25(OH)D₃ in captive marmosets, but 25(OH)D₃ is not the final product of vitamin D₃ metabolism. In addition to serum 25(OH)D_3, we measured the most physiologically active metabolite, 1,25-dihydroxyvitamin D₃ (1,25(OH)₂D₃), and the less well understood metabolite, 24,25-dihydroxyvitamin D₃ (24,25(OH)₂D₃) to characterize the marmoset's ability to metabolize dietary vitamin D₃. We present vitamin D₃ metabolite and related serum chemistry value colony reference ranges in marmosets provided diets with 26,367 (Colony A, N = 113) or 8,888 (Colony B, N = 52) international units (IU) of dietary vitamin D₃ per kilogram of dry matter. Colony A marmosets had higher serum 25(OH)D₃ (426 ng/ml [SD 200] vs. 215 ng/ml [SD 113]) and 24,25(OH)₂D₃ (53 ng/ml [SD 35] vs. 7 ng/ml [SD 5]). There was no difference in serum 1,25(OH)₂D₃ between the colonies. Serum 1,25(OH)₂D₃ increased and 25(OH)D₃ decreased with age, but the effect was weak. Marmosets tightly regulate metabolism of dietary vitamin D₃ into the active metabolite 1,25(OH)₂D₃; excess 25(OH)D₃ is metabolized into 24,25(OH)₂D₃. This ability explains the tolerance of high levels of dietary vitamin D₃ by marmosets, however, our data suggest that these high dietary levels are not required.     

Pathogenicity of some chrysosporium species isolated in France

In order to appreciate the pathogenicity of several geophilic Chrysosporium species (including Anixiopsis stercoraria, Chrysosporium keratinophilum, C. tropicum, C. pannorum, C. state of Arthroderma curreyi, C. state of A. multifidum, and C. state of A. tuberculatum), the authors have realized two series of experimental infestations. Inoculation of these fungi on the back of guinea pigs produced rare erythematous scaling lesions which spontaneously disappeared 3–5 weeks later. No real hair invasion was observed. In white mice, eight weeks after intraperitoneal inoculation, granulomas with necrotic center were observed in the peritoneal tissue with C. keratinophilum, C. tropicum, C. state of A. curreyi and C. state of A. tuberculatum. Conidia were often intact in necrotic centers and retrocultures were positive. With C. state of A. curreyi, spherical spores associated with rare budding cells were noted. The pathogenic role of these keratinophilic fungi is uncertain. However, their ability to remain viable for several weeks in skin and peritoneal tissue indicates that they could become pathogen in certain circumstances.This paper was presented at the X^th congress of the International Society for Human and Animal Mycology at Barcelona, Spain from June 27 to July 1, 1988.     

Immunophenotyping of acute myeloid leukaemia: relevance of analysing different lineage-associated markers

The immunophenotype of 135 previously untreated patients with FAB defined acute myeloid leukaemia (AML) was studied at diagnosis. The panel of reagents included monoclonal antibodies (MoAb) recognising myeloid-associated determinants (CD11, CD13, CD14, CD33 and others) as well as MoAb directed towards lymphoid antigens (CD7, CD10, CD19) and TdT. The results indicate that CD13 and/or CD33 are consistently expressed in AML and only rarely in ALL blasts (131/135 + ve cases, versus 4/130 in ALL). Lymphoid antigen expression was rarely detected when CD10 and CD19 were investigated in AML (0.9% and 2% + ve cases, respectively), whereas significant positivities were found for TdT and CD7 (20% and 10% respectively). Concerning FAB subtypes, two new MoAb (LAM3 and LAM7) proved very useful in the specific recognition of AML with monocytic features. The phenotype CD13+ and/or CD33+, CD9+, HLA-DR- was found to be almost exclusive for M3 AML. The response to induction chemotherapy was analysed in CD7+ and in TdT+ patients. In the latter group a statistically significant lower response rate was found with respect to TdT-ve-AML patients.     

Circadian Variations in the Affinities of Nad Kinase and Nadp Phosphatase for their Substrates, Nad+ and Nadp+ in Dividing and Nondividing Cells of the Achlorophyllous Zc Mutant of Euglena Gracilis Klebs (Strain Z)

-We have previously shown that NAD kinase and NADP phosphatase activities display circadian rhythms, in the soluble (SN) and membrane-bound (P) fractions of crude extracts of the achlorophyllous ZC mutant of the phytoflagellate Euglena gracilis (which displays circadian rhythmicity of cell division). We determined if changes in the affinity of NADP phosphatase and NAD kinase for their substrates, NADP⁺ and NAD⁺, were occurring by calculating the ratios 100(velocity found in Km conditions/velocity found in saturating conditions). The rationale was that if the affinity remained unchanged according to circadian time (CI), these values should always equal 50, independently of any changes in enzyme quantity; values greater than 50 should indicate increases in enzyme affinity, and values less than 50 decreases in affinity. Our results indicated that these values calculated for NADP phosphatase exhibited a complex pattern of rhythmicity, while those for NAD kinase displayed circadian variations strongly correlated with the rhythms in enzyme activity. The curves showed troughs at CT 00-04 both in dividing and nondividing cells and peaks at CT 18-20 or at CT 08-14 in cells sampled, respectively, from a dividing or a stationary culture. Such variations are indicative of changes in the kinetic properties of the enzyme, which may reflect modifications in its affinity either for effectors (such as Ca2⁺-calmodulin) or for its substrate, NAD⁺. This may be due to (i) the expression of different isoenzymes at different CTs; (ii) different posttranslational modifications of the enzyme; or (iii) concentrations of effectors varying in a circadian manner.     

Assessment of the mutagenicity of fractions from s-triazine-treated Zea mays

A water-soluble extract from maize plants exposed to 3 s-triazine herbicides (atrazine, simazine and cyanazine) has been shown to be mutagenic in strain TA100 of Salmonella. No mutagenic activity was observed in any control plant extracts using either water or a variety of organic solvents. Gel permeation studies of the extracts suggest that the mutagen(s) are small molecules (less than 1000 MW). HPLC fractionation suggests that the mutagens formed from each of the 3 herbicides are similar in polarity and water solubility, eluting in a 50/50 water:methanol fraction. Approximately 89% of 14C-labeled HPLC chromatographable metabolites of atrazine were also associated with this fraction, suggesting a close chemical link between a labeled but unidentified metabolite and the mutagenic activity.     

Protein synthetic activity and adenylate energy charge in Rhein-treated cultured human glioma cells.

The effect of Rhein (RH) on the protein synthetic activity and adenylate energy charge in human glioma cells cultured in vitro has been investigated. The results demonstrate that in RH-treated cells, the protein synthesis is strongly decreased, but no modifications in the qualitative pattern occur. The extent of inhibition is a function of the drug concentration as well as of the time of exposure. Such an inhibition must be ascribed mainly to a reduction of adenylate energy charge brought about by RH because of its effect on respiration and glycolysis. The correlation between the adenylate energy charge and cell viability, as well as the possibility of using rhein as a biochemical modulator to reduce or to reverse multidrug resistance, are also discussed.     

Effects of Salicylate on Virus-Infected Tobacco Plants

Salicylate watered onto the soil of tobacco plants in pots reduced the antigen accumulation and local lesion growth of tobacco necrosis virus mechanically inoculated on the leaves. It also retarded the growth of the necrotic centres of lesions and, in parallel, inhibited ethylene production from infected leaves. However, the therapeutic index of salicylate was very small and the chemical had to be applied in advance of, or at the same time as virus inoculation to give good levels of resistance. The number of lesions and their rate of appearance were not affected by salicylate. In addition, it did not induce resistance against multiplication, systemic spread or symptom severity in tobacco plants inoculated with a necrotic strain of potato virus Y. These findings suggest that salicylate is not likely to prove useful as polyvalent chemotherapeutic agent.     

Possible role of 06-methylguanine-DNA-transferase in the response of patients with primary tumor of the brain to chemotherapy using chloro-ethyl-nitroso-urea: results of a current study

We have started a study to measure the MT activity in surgical specimens from high grade human malignant gliomas, with the dual aim to (i), know whether lack of activity can be demonstrated in these tumors, and (ii), relate the measured levels of MT to the histology of the tumors and to the response of patients to chemotherapy with 1-(2-Chloroethyl)-3-Cyclohexyl-1-Nitrosourea (CCNU). To date, 12 Gliomas have been assayed. In 11 tumors, MT activities ranging from 30 to 150 fmoles/mg protein have been measured. The only negative specimen derived from a patient who had received radiotherapy before surgery. At the present stage of the study, therefore, we have no unequivocal evidence for the existence of MT-deficient Gliomas.