Biological effects of D2O administration to Coturnix japonica

Levels of 7.8, 18.5 and 26 mole % deuterium oxide were administered sequentially to $\text{Coturnix japonica}$ (Japanese quail) via the drinking water. The primary effect observed was on egg frequency, which decreased from a normal level of 0.89 for 7.8 mole % D₂O to a low of 0.38 during the administration of 26 mole % D₂O. Adverse symptoms, such as hyperexcitability, convulsions, skin ulcerations, comatosity, weight loss, or death, which have been associated with deuterium toxicity in other animals, were not observed in these experiments. The amount of deuterium deposited in the water of the egg was 6.9, 13.98, and 19.83 mole % when 7.8, 18.5 and 26 mole % deuterium respectively was administered. For each period, the deuterium content of egg water rapidly reached a maximum concentration after which the concentration decreased slightly. This dilution effect has not been noted previously in body fluids from other animals.     

A novel galactosyl-binding lectin from the plasma of the blood clam,Anadara granosa (L) and a study of its combining site

Control Analysis has been carried out in the first steps of a rat liver glycolytic system. Attention has been focused on the effect of several glucose concentrations on the control, particularly regarding the role of glucokinase. From kinetic studies of the whole metabolic system we have obtained information on the flux variation under different glucose concentrations. This information together with the kinetics of glucokinase has allowed us to calculate Flux Control and Elasticity Coefficients for glucokinase and the Response Coefficient of the system with respect to glucose. The changes in of the value of Flux Control Coefficients demonstrates that in conditions of low glucose concentration, glucokinase is the main enzyme in controlling the flux through the pathway, but at high glucose concentration the control moves to phosphofructokinase. Next, we have compared our results with those obtained with the shortening and titration method, previously described (Torres, N.V., Mateo, F., Mélendez-Hevia, E. and Kacser, H., (1986) Biochem. J. 234, 169–174; Torres, N.V. and Meléndez-Hevia, E. 1991. Molec. Cell. Biochem. 101, 1–10). Furthermore, from knowledge of the enzyme kinetics of the system we have been able to build a model of the pathway that allows us computer similation of its behavior and calculation of the Flux Control Coefficient profile at different glucose concentrations. By the three methods the results correlate, supporting the use of the pathway substrate as external modulator of the metabolic system as a tool for practical application of Control Analysis.     

Termination of pregnancy in cases of fetal death in utero by intravenous prostaglandin F2alpha.

Delivery was induced by an intravenous infusion of prostaglandin F2alpha (PGF2alpha) in gradually increasing doses in 30 consecutive cases of fetal death in utero after the 28th week of gestation. Twenty patients delivered during the first day of prostaglandin administration, 9 on the second day, and 1 patient not until the third day of infusion. It is concluded, that intravenous PGF2alpha appears to be superior to oxytocin in termination of pregnancy under these conditions.     

Apparent molecular weight of substance P/neurokinin-1 receptors determined using a photoaffinity labelled probe, [(3'-125I) D-Tyro, (4'-N3)Phe8, Nle11]-substance P

A photoreactive derivative, [(3'-125I) D-Tyro, (4'-N3)Phe8, Nle11]-substance P (SP) was prepared and iodinated using carrier-free [125I] to determine the apparent molecular weight of one sub-type of neurokinin (NK) receptor, the SP/NK-1 type. The unlabelled analogue competed for [3H]-SP sites with an IC50 of 10 nM. The radioactive photoprobe (KD approximately 0.17 nM, Bmax = 15.6 fmol/mg protein) was used to photoaffinity label membranes prepared from rat brain. Autoradiographs revealed that a single band with an apparent molecular weight of 46,000 daltons was specifically labelled. This labelling was inhibited by non-radioactive SP in a concentration-dependent manner (1.0 nM-0.1 mM) suggesting that the observed labelling represents the SP/NK-1 receptor type.     

DNA-binding domain of human c-Myc produced in Escherichia coli.

We have identified the domain of the human c-myc protein (c-Myc) produced in Escherichia coli that is responsible for the ability of the protein to bind sequence-nonspecific DNA. Using analysis of binding of DNA by proteins transferred to nitrocellulose, DNA-cellulose chromatography, and a nitrocellulose filter binding assay, we examined the binding properties of c-Myc peptides generated by cyanogen bromide cleavage, of mutant c-Myc, and of proteins that fuse portions of c-Myc to staphylococcal protein A. The results of these analyses indicated that c-Myc amino acids 265 to 318 were responsible for DNA binding and that other regions of the protein (including a highly conserved basic region and a region containing the leucine zipper motif) were not required. Some mutant c-Mycs that did not bind DNA maintained rat embryo cell-cotransforming activity, which indicated that the c-Myc property of in vitro DNA binding was not essential for this activity. These mutants, however, were unable to transform established rat fibroblasts (Rat-1a cells) that were susceptible to transformation by wild-type c-Myc, although this lack of activity may not have been due to their inability to bind DNA.     

Isolation and structural studies of phosphate-containing oligosaccharides from alkaline and acid hydrolysates of Streptococcus pneumoniae type 6B capsular polysaccharide

The capsular polysaccharide of Streptococcus pneumoniae serotype 6B [----2)-alpha-D-Galp-(1----3)-alpha-D-Glcp-(1----3)-alpha-L-Rhap-( 1----4)- D-RibOH-(5-P----]n was depolymerised under alkaline (NaOH) and acidic (HF) conditions. The former treatment yielded, as the major component, alpha-2-P-Galp-(1----3)-alpha-Glcp-(1----3)-alpha-Rhap-(1----4)-5- P-RibOH. The latter treatment at -16 degrees gave alpha-Galp-(1----3)-alpha-Glcp-(1----3)-alpha-Rhap-(1----4)-Rib OH-(5-P----2)- alpha-Galp-(1----3)-alpha-Glcp-(1----3)-alpha-Rhap-(1----4)-Rib OH and at 4 degrees gave alpha-Galp-(1----3)-alpha-Glcp-(1----3)-alpha-Rhap-(1----4)-Rib OH. These oligosaccharides were characterised by sugar analysis, f.a.b.-m.s., and 1H- and 13C-n.m.r. spectroscopy.     

Comparative evaluation of fresh, fixed, and cryopreserved solid tumor cells for reliable flow cytometry of DNA and tumor associated antigen.

Five different protocols for the short-term preservation of cells used for multiparameter flow cytometric assay of tumour associated antigens (TAA) and DNA were assessed in cell suspensions prepared by mechanical disaggregation of 15 gynecological tumors. The protocols at 4 degrees C were 1) storage in buffer, 2) storage in 50% methanol, and 3) storage in buffer after formalin fixation. Tissues were also cryopreserved as cell suspensions and tissue blocks. When the TAA expression and DNA histograms of the preserved cells were compared with those in fresh cell suspensions, cryopreservation was found to be the best method: TAA expression was well preserved and there was a good correlation between TAA expression and the quality of the DNA histograms, respectively, in fresh and cryopreserved cells (RS: 0.82-0.91, P less than 0.001 for all TAAs). The cell suspensions preserved at 4 degrees C all showed a significant increase in background fluorescence (P less than 0.05) and a reduction in the TAA specific fluorescence (P less than 0.011). Methanol fixation was better than buffered formalin for the proteins studied, though both gave significantly worse results than cryopreservation. The quality of these cell suspensions and the correlation with TAA measurements in fresh cell suspensions deteriorated progressively with time, particularly if they were stored more than a week.     

Eicosanoids in breast cancer patients before and after mastectomy.

In 19 patients with a malignant breast tumor, tumor tissue and blood were taken to determine the eicosanoid profile and platelet aggregation. Values were compared with those of patients with benign tumors (n = 4), or undergoing a mammary reduction (n = 7). Postoperatively, blood was taken as well in order to compare pre- and postoperative values. Eicosanoids were measured in peripheral blood monocytes and mammary tissue by means of HPLC; furthermore, TXA2, 6-keto-PGF1 alpha, and PGE2 were determined by RIA. Differences in pre- and postoperative values of cancer patients were seen in plasma RIA values: PGE2 and 6-k-PGF1 alpha were significantly higher preoperatively when compared with postoperatively, however, such differences were seen in the control groups as well. Compared to benign tumor or mammary reduction test material the eicosanoid profile of tissue obtained from malignant mammary tumors showed important differences. Except for PGF2 alpha, HHT and 15-HETE no detectable quantities of eicosanoids were found in the non-tumor material, whereas in the malignant tumor material substantial quantities of a number of eicosanoid metabolites were present. Statistically significant correlations could be established between patient/histopathology data and the results of the platelet aggregation assays, e.g. between menopausal status and ADP aggregation; oestrogen receptor (+/-) and collagen and arachidonic acid aggregation, inflammatory cell infiltration score and arachidonic acid aggregation and fibrosis score and ADP aggregation. The results show that eicosanoid synthesis in material from mammary cancer patients is different from that in benign mammary tissue. The implications, in particular, in relation to future prognosis of the patient, remain obscure.