Effect of Sodium Molybdate on Androgen Binding to Its Receptor from Shionogi Carcinoma 115

The effects of molybdate on the binding characteristics of androgen receptor from the androgen-dependent mouse tumor (Shionogi carcinoma 115) with 17/β-hydroxy-5α-androstan-3-one were studied by the charcoal adsorption method. The dissociation constant (Kd) was (4.65±0.54) ×1O-11 M in the presence of 10-12 mM sodium molybdate, which was one order of magnitude lower than the value without molybdate ((4.54±0.72)× 10-10 M). Since the half life of the binding activity of unbound receptor was extended from 10 h to 75 h by adding molybdate, the effects of chaotropic reagents on binding were studied in the presence of molybdate. KC1 (0.3 -1.0 M) remarkably increased Kd without affecting the maximum binding capacity or the dissociation rate. KSCN (>0.1 M) had no effect on Kd but increased the dissociation rate, and while at concentrations at or above 0.5 M it completely inhibited the androgen binding to the cytosol receptor. Urea (0.5-2.0 M) increased Kd proportionally to the increase in the dissociation rate. Kd was also increased by 0.2-0.5 M guanidine, but the maximum binding capacity was reduced

On the q-Strong Diffie-Hellman Problem

This note is an exposition of reductions among the q-strong Diffie-Hellman problem and related problems

Circular Dichroism Quantitative Estimate of α-Helix Content of Human Serum Albumin in the Presence of NaSCN, Urea and KCl at Various pH

Conformational changes in human serum albumin (HSA) in the presence of several concentrations of NaSCN, urea and KCl at various pH were examined quantitatively on the basis of rotational strength at 208 nm by means of circular dichroism (CD). The α-helix content of HSA was markedly dependent on concentrations of NaSCN and urea, but not on KCl. However, when these salts coexisted with a concentration of hydrogen ion in the albumin solution, the α-helix content of HSA was markedly dependent on all these salts. Among these salts, the distortion power of NaSCN on the conformational stability of the peptide backbone was undoubtedly several hundred times stronger than that of the other salts. Conformational changes in HSA were scarcely observed at pH 4.8-10.0 under a constant concentration of each salt, but were more dependent on pH outside of the above range regardless of salt. The α-helix content of highly denaturated HSA in solution containing a high salt concentration was less dependent on the hydrogen ion concentration, while at a low concentration of each salt, it was pH dependent, as if there was no salt

The Influence of Cyclophosphamide on Accumulation of Peritoneal Exudate Cells Responding to PPD in BCG- sensitized Guinea Pigs

In BCG-sensitized guinea pigs, the influence of pretreatment with cyclophosphamide (CY) (300 mg/kg) 3 days before sensitization on peritoneal exudate cell accumulation in the PPD-induced delayed type hypersensitivity reaction was analyzed by using the sponge implant method. The number of polymorphonuclear neutrophils (PMN) accumulating in the intraperitoneally implanted sponges containing 50 μg of PPD was increased more than that in the untreated group 24-48 hours after challenged implantation when CY pretreated. The accumulation of mononuclear cells, however, was decreased. The enhanced effect of CY pretreatment on the immune response to PPD in tuberculin type of delayed type hypersensitivity through the selective inhibition of suppressor cells may be evaluated in terms of the increase in PMN accumulating at the reaction site

The Influence of D-penicillamine on Granuloma Formation in Implanted Collagen Sponges in Ferritin-sensitized and Non-sensitized Guinea Pigs

In ferritin-sensitized and non-sensitized guinea pigs, using the method of granuloma formation within peritoneally implanted collagen sponges that were either impregnated or not impregnated with ferritin, the effects of D-penicillamine on the cellular aspects of thus created granulomas were quantitatively evaluated by scheduled administration. Daily administration of D-penicillamine (200 mg/kg) for 14 days before and 10, 14 or 18 days after the sponge implantation decreased small mononuclear cell population (SMN) which consisted of lymphocytes, small monocytes and plasma cells, on the 10th-18th days in sponge granulomas in both sensitized and non-sensitized groups, but the administration for 14 days before the sponge implantation higher increased SMN infil- tration on the 14th day in sensitized group. This phenomenon disclosed a close association with a marked infiltration of perivascular lymphocytes and plasma cells in the presence of granulomatous inflammation with the involvement of the delayed hypersensitivity reaction. The enhancement of the dominant lymphocytes infiltrating perivascularly by D-penicillamine may be mediated by chemotactic factors such as lymphokines inducing the delayed hypersensitivity reaction. On the other hand, the frequency of foreign body multinucleated giant cells was decreased by daily administration of D-penicillamine before and after implantation in both groups. This decrease in the number of the giant cells is considered to be due to inhibition of accumulation in the sponges of macrophages and/or monocytes to be fused

Growth Characteristics of KB and RAJI Cells in the Liquid Culture Medium in Relation to the Human Tumor Stem Cell Assay for Anti-Tumor Agents

Recently the chemosensitivity assay with clonal human tumor stem cells in liquid medium have been developed. We have investigated the optimal conditions for culture and counting of KB cells, which derived from a human epidermoid carcinoma and grow as a sheet adhered to the bottom surface of the culture, and RAJI cells, which derived from Burkitt lymphoma and grow as a suspension in liquid medium, as the representatives of the human tumor cells. Both stock cells were maintained in Eagle\u27s MEM medium plus 10 per cent calf serum in C02 incubator at 37°C. Trypsinized cell suspensions were delivered in plastic wells with different culture media and incubated for different periods. Then the cell number was counted by the Coulter Counter in ISOTON II solvent. For KB cells, the culture medium should not be changed for 72 hours, otherwise enough cell number could not be obtained. To prevent the aggregation of KB cells in ISOTON II, calf serum (10%) was effective and EDTA (0.02%) had an additive effect. RAJI cells did not aggregate in ISOTON II. Ethanol and dimethylsulfoxide inhibited the growth of RAJI cells, but almost no inhibition was noted when the initial cell number was more than 8×l04/ml. Ethanol was more toxic. Both solvents, however, did not affect the growth of KB cells

Characteristics of Multiple Choice Questions Intrinsic to Their Format

Multiple choice questions (MCQs) are not suitable for testing an examinee\u27s knowledge. Examiners cannot distinguish whether questions have been answered by random guessing or not. In many types of MCQs, knowledge of only two items (a correct terminal) out of four or five is sufficient to answer correctly. If an examinee can identify a correct terminal, he can answer a question correctly even if all other items are blank. In the multiple completion type problem (K-type) and its modifications, one to five correct terminals exist depending on answer codes. Therefore, even if an examiner presents difficult material in an item, an examinee could receive points by locating another correct terminal. On the other hand, even if an examinee knows all three correct items appearing in the answer code (e.g. type K, answer code "A"), he is still compelled to make a random guess and could select the wrong answer. Therefore the scores achieved by the examinees on such tests can not be said to truly reflect their actual knowledge of a subject. MCQs can, however, be used for self-assessment

Chalcones from Methanol Extract of Humulus Lupulus

Extracts of Humulus Lupulus yielded two known compounds, isoxanthohumol and xanthohumol, and two new chalcone derivatives, 3\u27-(isoprenyl)- 2\u27,4 - dihydroxy - 4\u27,6\u27- dimethoxychalcone and 2\u27,6\u27-dimethoxy-4,4\u27-dihydroxychalcone. Their structures were established by spectral methods