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PubMed1979

Scintillation-proximity assay of antigen-antibody binding kinetics: concise communication.

Tritiated latex particles and scintillant latex particles have been covalently coated with an antigen (human albumin) and both types of particles are than combined in dilute aqueous suspensions. The formation of antibody-induced dimer and higher-order aggregation resulted in scintillations that could be measured in a standard liquid-scintillation counter, energy-gated for H-3. Rabbit anti-human antiserum was easily detected at a titer of 1:10(6). Human albumin, in the inhibition mode, was also easily detected at 0.1 ng/ml. Since the samples are nondestructively assased, it was possible to examine the kinetics of aggregation under a variety of conditions.

Albumins↗

PubMed1977

Benzo[a]pyrene metabolizing activity of cultured cells as determined by a simplified radiometric method.

Benzo[a]pyrene metabolism in various kinds of mammalian cultured cells was measured by a simplified method. Cells growing in the bottom of glass test tubes were treated with 2micron of 14C-benzo[a]pyrene for 24 hr; unmetabolized benzo[a]pyrene was then extracted with organic solvents in the same test tube, and the amount of water-soluble products recovered in the aqueous phase was measured by a liquid scintillation counter. Among rodent embryo cells, embryo cells of C3H/He mice and Syrian hamsters showed a higher activity in benzo[a]pyrene metabolism than those of DDD, AKR, and C57BL/6 mice. Several cell line sensitive to density-dependent inhibition, such as Y-AK, DL1, and C3H/10T1/2, actively metabolized benzo[a]pyrene to water-soluble products. The metabolizing activity of C3H/He mouse embryo cells was markedly enhanced by pretreatment with benz[a]anthracene. tthe amount of water-soluble products by phytohemagglutinin-stimulated human lymphocytes was much less than that by most cultured cell lines and embryo cells, but clearly increased with extension of culture days.

Animals↗

PubMed1983

[Effects of nifurtimox, benznidazole, and beta-lapachone on the metabolism of DNA, RNA and proteins in Trypanosoma cruzi].

Nifurtimox and benznidazole have trypanostatic actions in vitro and inhibit the incorporation of [3H] thymidine, [3H] uridine and L-[3H] leucine in T. cruzi macromolecules. The effect of nifurtimox may be explained by (a) direct inhibition of nucleic acid biosynthesis, or (b) generation of the oxygen radicals in T. cruzi and therefore, only mechanism (a) should be valid. In order to obtain more information on the action of these drugs on T. cruzi, in the present study we examined the effect of nifurtimox and benznidazole on DNA, RNA and protein turnover in epimastigote (culture) forms of the parasite. Complementary experiments were performed with beta-lapachone that, like nifurtimox, generates oxygen radicals in T. cruzi. Epimastigotes (Tulahuen strain) at the exponential-phase of growth were cultured with [3H] thymidine, [3H] uridine or L-[3H] leucine to label DNA, RNA and protein, respectively. After incubation, the cells were washed free of radioactive precursor, resuspended in fresh medium and reincubated at 30 degrees C with nifurtimox (10 or 100 microM), benznidazole (38 or 380 microM) or beta-lapachone (1.6 or 7.8 microM), for 1-3 hours. Controls were incubated without drug. At one hour time intervals, sampler were taken, washed free of medium and filtered through 0.45 microns Metricel filters. The filters were washed with 10% trichloroacetic acid to remove the acid soluble material, and after drying, the radioactivity incorporated in DNA, RNA and protein was counted with a scintillation counter. The results show that after elimination of the labelled precursors, 3H activity in DNA, RNA and protein decayed as a function of the time of incubation. Nifurtimox, benznidazole and beta-lapachone, stimulated in all cases they decay of the incorporated radioactivity. Calculation of "half-life" values for DNA, RNA and protein(s) indicated that nifurtimox and beta-lapachone exerted their greatest effects on DNA while benznidazole increased the decay of DNA, RNA and protein to about the same extent. Taking into account the effects of nifurtimox and beta-lapachone on DNA stability, specific lesions (single-strand breaks) were investigated in DNA from control, nifurtimox, benznidazole or beta-lapachone treated epimastigotes. The number of single-strand breaks was (per 10(6)b) 25 with 100 microM nifurtimox, 1.4 with 380 microM benznidazole and 45 with 7.8 microM g-lapachone. Interestingly enough, after reincubation of nifurtimox-damaged epimastigotes in fresh medium for 24 hours, recovery of DNA lesions could be observed.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

PubMed1977

[Simple method of measuring the physiological form the velocity of intestinal transit].

The velocity of intestinal transit was studied in 24 healthy volunteers using as a marker a small rubber bag which contained 7 to 10 microcuries of NaI 131. The bag was ingested and its passage along the digestive tract followed over the abdominal surface with the help of a collimated scintillation counter connected to an automatic counting system. The time elapsing since ingestion of the bag until its expulsion with feces was taken as the intestinal transit time. In a normal subject, transit of the bag was compared with the one of plastic radioopaque pellets whose passage along the intestine can be followed radiologically, and which at present are considered the best existent marker to measure velocity of intestinal transit. The bay and pellets progressed practically together along the digestive tract. The described method is thought to be very useful to measure in a phisiologic and simple way the velocity of intestinal transit.

Adolescent↗

PubMed1984

[Pathogenetic significance of adenosine deaminase in autoimmune diseases].

UNLABELLED: Adenosine deaminase (ADA: E.C.3.5.4.4.) is one of the catabolic enzymes of purine nucleotide. In 1972 Gibllet has discovered two cases of ADA deficiency combined with severe immunodeficiency (ADA-. SCID) with remarkable dysfunction in both T and B cell. Thereafter, it has been believed by many investigators that deficiency of purine metabolic enzyme had played important role in immune function mechanism. Rheumatoid arthritis (RA) is one of the autoimmune diseases which is very frequently seen, but its pathogenesis is not distinct yet. This study has shown how the catabolic pathway of erythrocytes and lymphocytes in RA has been distorted. MATERIALS: Erythrocytes and lymphocytes in peripheral blood were obtained from patients with RA (48 cases), SLE (4), primary gout (55) and healthy control (23). 2. T cell and non-T cell in peripheral blood were obtained from patients with RA (5), gout (55) and healthy control (28). 3. T cell and non-T cell in joint fluid were obtained from patients with RA (19) and osteoarthritis (OA (9)). METHODS: Erythrocytes and lymphocytes were separated from peripheral blood by Ficoll-Conray (density 1,077) by use of gradient centrifugation method. The lymphocytes with PBS was mixed with sheep red blood cells. E rosette-positive (T cell) and E rosette-negative (non-T cell) populations were separated from lymphocytes in peripheral blood and joint fluid by human sodium metrizoate Ficoll mixed solution (density 1,090) by use of gradient centrifugation method. Erythrocytes bursted at -70 degrees C and lymphocytes were sonicated for 25 sec. at 20 kHz. The reaction mixture which consisted of 0.2 mM Tris-HCl buffer (pH 7.4), 30 mM [8-14C] adenosine and the samples was incubated at 37 degrees C for 30 min. After incubation, adenosine, inosine and the reaction mixture were applied on DEAE-cellulose paper. Radioactivity of the samples was measured with liquid scintillation counter. RESULTS: There was no significant difference in ADA activity of erythrocytes between normal male and female, but a significant difference was found in ADA activity of lymphocytes among its subpopulations. ADA activity of erythrocytes and lymphocytes in RA patients was much lower than the other groups (gout and normal subjects). Particularly, ADA activity in T cell was the lowest. In gouty patients, ADA activity of erythrocytes and T cell was higher. ADA activity of peripheral erythrocytes in RA patients was lower than that of joint fluid.(ABSTRACT TRUNCATED AT 400 WORDS)

Adenosine Deaminase↗

PubMed1983

Effect of naloxone on endotoxin-induced pulmonary platelet sequestration.

The opiate antagonist, naloxone, has been shown to obviate hypotension and to improve survival of animals with shock induced by endotoxin, hypovolemia, and spinal transection. This study was done to evaluate the effects of naloxone on pulmonary platelet trapping (PPT) and on platelet aggregability in dogs with endotoxin shock. Dogs with 51Cr labelled platelets were treated with naloxone before and after induction of endotoxin shock. PPT was assessed by measuring 51Cr activity in lung and blood using a gamma scintillation counter. ADP induced platelet aggregability was measured in an aggregometer. PPT seen in endotoxin shocked controls was obviated by naloxone treatment; this effect was more pronounced in pretreated dogs. Naloxone treated animals did not show the increased platelet aggregability normally seen in endotoxin shocked dogs. These results suggest the applicability of naloxone therapy for adult respiratory distress associated with shock.

Animals↗

PubMed1983

[In vitro method determining sensitivity of anticancer agents by incorporation of radioactive precursors].

A new sensitivity test of anticancer agents was developed to measure the lethal effects of cancer cells by the incorporation of radioactive precursors. The thousand cancer cells were cultured in a microplate in the presence of anticancer agents. These cells were exposed to radioactive precursors. Two or three days later, the cancer cells were harvested on a glass fiber filter by a multiple automatic cell-harvester and the incorporation of precursors was counted by a liquid scintillation counter. In this study, the in vivo results of drug testing in animal model systems were compared with drug sensitivities. Mice inoculated Ehrlich ascites cells were treated with various kinds of anticancer drugs. The development of the cells was compatible with the result of the sensitivity test. The growths of Lauson and ME-180 cells derived from human cancers implanted subcutaneously to nude mice were also well correlated with this sensitivity test.

Animals↗

PubMed1976

Iron absorption in gastric and duodenal pathology in patients with iron deficiency anaemias.

Absorption of radioactive iron was studied in 87 patients with different types of iron deficiency anaemias and in 23 healthy subjects. The subjects were given 1...2muci of radiactive iron in the form of FeSO4 together with 5 mg of nonradioactive iron as a carrier and 100 to 150 g of white bread, radioactivity on the whole body being studied with a big liquid scintillation counter 4 pi (BLSC-2). In clinical observations and in single experiments on volunteers there was no conformity of the values of absorption with the levels of acid-formation. But in the same time the gastric juice from an anaemic horse almost doubled iron absorption in healthy individuals. Marked morphological changes in the gastric mucosa inhibited the absorption in the intestine and the degree of increase of absorption in patients with anaemia depended to some extent on the morphological conditions of the gastric mucosa. When healthy subjects and patients with iron deficiency anaemia were given bread "enriched" with iron before baking instead of common bread with "external" mark there was observed similar correlation between the values of absorption but the figures were somewhat lower.

Anemia, Hypochromic↗

PubMed1980

The effect of a milk diet on the retention of 74As labelled arsenic in mice.

The effect of 3 diets with different proportion of milk proteins on retention of arsenic was studied in mice. Arsenic was administered via drinking water in concentration 50 mg As [III] per litre labelled with 74As in amount 2.96 MBq per 100 ml. After 2, 4, 8, 16 and 32 days of exposure the mice in groups of 6 each from all 3 experimental cohorts were decapitated and the content of 74As was determined in whole body, blood, liver, kidneys, spleen, lungs and heart by measuring of the activity in Gamma Scintillation Counter Tesla. From the intake of drinking water and amount of arsenic found in the experimental animals was calculated retention of arsenic in mice at different exposure intervals in all three diets. The values of arsenic found at the exposure intervals in examined materials of all three experimental cohorts were compared. The results obtained indicate that a milk diet has no adverse effect at exposure to arsenic in the sense of enhancing of its retention in mice at given experimental conditions. The found data seemed to suggest that the milk protein rich diet caused retardation of the increase of arsenic concentrations in blood, liver and kidneys that might lead at a lower exposure rate to a decrease in arsenic content in tissues of exposed animals.

Animals↗

PubMed1984

Total hydrolyzable glycerol in amniotic fluid, and its relationship to fetal lung maturity.

We describe an enzymic quantification of total hydrolyzable glycerol in amniotic fluid. An extract of amniotic fluid is hydrolyzed in mild alkali, without pretreatment with lipase. The resulting glycerol (some of which may be derived from trace amounts of triglyceride) is then enzymatically phosphorylated with adenosine 5'-[gamma 32P]triphosphate to yield glycerol [gamma 32P]phosphate. After removal of excess [gamma 32P]ATP by charcoal, the radioactivity of the glycerophosphate is measured in a liquid scintillation counter. The close correlation (r = 0.96) we found between total hydrolyzable glycerol and phosphatidylglycerol indicates that the contribution of triglyceride to the value for total glycerol is inconsequential. This method is less time consuming and more precise than the method for phosphatidylglycerol.

Amniotic Fluid↗

PubMed1984

[Optimization of liquid scintillation counting by using multichannel pulse-height analyzer].

The method for determining optimum conditions of a liquid scintillation counter (LSC) for low-level counting of tritium was studied. To compare the lower limit of detection, the figure of merit EM/square root B was used. Th measurement system is a LSC connected with a multichannel pulse-height analyzer (MCA). Both of tritium spectra and background spectra were searched for the condition that maximizes the figure of merit. The optimum condition obtained by using the MCA was fitted for a single channel pulse-height analyzer of the LSC. The figure of merit obtained by this method was 20.6% greater than that obtained by the balance point method.

Arginine↗

PubMed1984

Induction of unscheduled DNA synthesis in rat stomach mucosa by glandular stomach carcinogens.

Induction of unscheduled DNA synthesis (UDS) (repair DNA synthesis) in stomach pyloric mucosa of the F344/- DuCrj rat was examined in in vitro organ cultures in the presence of tritiated thymidine ([3H]dThd) and hydroxyurea after administration of chemical carcinogens in vivo. The DNA fraction was extracted from the cultured tissue, and the incorporation of [3H]dThd into DNA was determined in a liquid scintillation counter. DNA concentration was determined spectrophotometrically with either diphenylamine or 3,5- diaminobenzoic acid. A good correlation between induction of UDS and site specificity of carcinogens was observed. The glandular stomach carcinogens N-methyl-N'-nitro-N-nitrosoguanidine (CAS: 70-25-7), N-ethyl-N'-nitro-N-nitrosoguanidine (CAS: 63885-23-4), N-propyl-N'-nitro-N-nitrosoguanidine, 4-nitroquinoline 1-oxide (CAS: 56-57-5), and N-nitroso-N-methylurethane (CAS: 615-53-2) induced UDS in the pyloric mucosa of the stomach. UDS could be detected 2-4 hours after administration of carcinogens in vivo by the present method. The forestomach carcinogens 1-methyl-1-nitrosourea (CAS: 684-93-5) and aristolochic acid (CAS: 1398-06-7) and the nongastric carcinogens 2-acetylaminofluorene (CAS: 53-96-3), 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole, 3-amino-1-methyl-5H-pyrido[4,3-b]indole, and dimethylnitrosamine (CAS: 62-75-9) did not induce UDS in the pyloric mucosa.

Animals↗

PubMed1983

Estimation of lipid assimilation from faecal samples using 14C-triolein as tracer and 51CrCl3 as non-absorbable marker.

14C-triolein was investigated as tracer of dietary lipids from faecal measurements in 48 consecutive gastrointestinal patients. Simultaneously, 51CrCl3 was investigated as non-absorbable marker. Faecal 51Cr was measured in a whole-body scintillation counter and faecal 14C by means of a combustion technique. This technique permitted accurate measurement of faecal 51Cr and faecal 14C in each stool collected over a 6-day period. The investigation showed that the transit time of 51Cr was slightly shorter than the transit time of 14C-triolein in patients with high faecal excretion of 14C. Nevertheless, total faecal 14C, estimated from the ratio between 14C and 51Cr in two stools, correlated very closely with measured, cumulative faecal 14C (r = 0.99, P less than 0.001). 51CrCl3 was therefore considered useful as a non-absorbable marker. The 14C-labelling of triolein was stable during gastrointestinal transit. Qualitatively, estimated faecal 14C agreed with faecal fat diagnosing steatorrhoea in 97% (95% confidence limits 90-100%) of the patients with quantitative faecal collections. Quantitatively, a significant correlation with faecal fat was found (r = 0.82, P less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMedDate not supplied

[Effect of the structure of the cell nucleus chromatin on absorption of low-energy beta-radiation emitted from an incorporated source].

To study the energy absorption in cell nuclei the analysis was made of the level of registration of beta-particles, emitted by the incorporated tritium, using a liquid scintillation counter. It was shown that the treatment, modifying the chromatin structure, changed the number of beta-particles registered. The pattern of the spectral changes indicated that the effect observed was not the result of the quenching processes. The effect was absent when the source of a higher energy (14C) was used. The authors submit the conceptions concerning the mechanisms of the phenomenon observed which are confirmed by the theoretical studies.

Animals↗

PubMed1983

[Analysis of cytotoxicity in cultured choriocarcinoma cell lines using methotrexate and actinomycin-D].

The cytotoxicity of methotrexate (MTX) and actinomycin-D (Act-D), and the influence of Citrovorum factor on MTX-treated cells were analyzed in vitro, using two choriocarcinoma cell lines (BeWo and SCH). HCG and beta-HCG in medium were measured with a radioimmunoassay kit, and 3H-MTX,-thymidine, and-uridine with a liquid scintillation counter. The following results were obtained. The MTX resistant cell line of BeWo, named BeWo, was selected by continuous exposure to increasing concentration of MTX in culture medium. The resistant cell was 50 to 100 times as resistant to MTX as the parent BeWo to the inhibition of cell growth and the development of resistance was accompanied by two-third decrease in 3H-MTX transport. The cytotoxicity of MTX and Act-D were found to increase linearly with the drug dose for concentrations between 10(-9) and 10(-4)M, 10(-10) and 10(-7)M, respectively. Act-D caused lethal damage in three choriocarcinoma cells (BeWo, SCH and BeWo) at one-thousandths the concentration of MTX. Citrovorum factor given within twelve hours following the start of methotrexate administration decreased in 3H-MTX transport and inhibited MTX-induced growth.

Cell Division↗

PubMed1984

The role of lymphovenous communication in the development of postmastectomy lymphedema.

Forty women were investigated 6 to 24 months after radical mastectomy for the presence of functioning lymphovenous communications in the arm; 20 cases were edematous and the rest were not. Ten normal volunteer women were also investigated and served as controls. Iodinated (I125) human serum albumin was injected intralymphatically in the arm, and samples of blood were taken from both basilic veins simultaneously at 5, 10, 15, 30, 45, and 60 minutes. The radioactivity of each sample was determined with a scintillation counter. Lymphangiography was performed in all cases 1 month after the isotopic studies and lymphangiograms were evaluated for the presence of lymphovenous shunts. In the volunteers and the edematous postmastectomy group, there was negligible lymphovenous shunting of labeled albumin. In the nonedematous postmastectomy group, there was an increased quantity of local lymphovenous transfer of iodinated albumin. Lymphovenous shunts were detected radiologically in two patients who did not have edema. On the basis of our observations, the incidence of postmastectomy lymphedema is predetermined and is a consequence of the lack of existence of lymphovenous communications that can allow adequate lymph flow drainage from the arm after radical dissection of axillary lymph nodes.

Arm↗

PubMed1984

Assembly of transferred normal spleen cells in situ at sites eliciting the delayed hypersensitivity reaction to tumor antigens in mice.

Cell assembly at sites eliciting the delayed hypersensitivity reaction (DHR) to tumor antigens was studied using 51Cr-labeled cells. C3H/He mice were strongly immunized with syngeneic MM46 tumors. The MM46 antigen fraction elicited tumor-specific DHR when injected into the footpad of MM46-immunized mice. The test mice were then injected iv with 51Cr-labeled spleen cells from normal mice, their feet were cut off, and radioactivity in the feet was counted in a gamma-scintillation counter as a measure of the assembly of 51Cr-spleen cells at the site of the antitumor DHR. Assembly of spleen cells persisted for 48 hr after injection of the antigen fraction. Local passive transfer of the DHR also induced assembly of spleen cells, indicating that it is a cell-mediated immune reaction. On the basis of these results, the role of cell movement in host defense systems against tumors is discussed.

Animals↗

PubMed1982

Diamine oxidase in the diagnosis of ruptured fetal membranes.

Diamine oxidase activity is present in amniotic fluid but absent from vaginal secretions, providing a method for diagnosing rupture of membranes. Vaginal secretions were absorbed onto sterile paper strips, eluted, and assayed for diamine oxidase activity. Interfering substances included maternal serum, iodine antiseptics, and large amounts of meconium. Two of 109 prenatal clinic (negative control) specimens displayed measurable diamine oxidase activity; one of 144 postamniotomy (positive control) specimens had no diamine oxidase activity. Of 75 test specimens obtained by speculum examination and 488 test specimens obtained without the aid of a speculum, 18 and 62, respectively, displayed a diamine oxidase test result different from results of conventional tests (nitrazine paper, ferning, fetal cell stains). These discrepancies are discussed in view of the utility of the diamine oxidase test as an adjunct to conventional methods for diagnosing rupture of membranes. The diamine oxidase test appears to be objective, sensitive, quantitative, and capable of detecting amniotic fluid leaks more than 25 hours after rupture of membranes. It can be performed in 1 hour and requires a scintillation counter.

Amine Oxidase (Copper-Containing)↗