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PubMed2001

Prevalence of Helicobacter pylori in gastric cancer in a South-East Asian population by 14C-urea breath test.

BACKGROUND: Helicobacter pylori is believed to play an important role in the aetiology of gastric cancer. There is a great variability in seropositivity and histological frequency of H. pylori in gastric cancer. The present prospective study investigates the prevalence of H. pylori infection in gastric cancer patients using 14C-urea breath testing. METHODS: Patients with endoscopic biopsy-proven gastric cancer were fasted for 6 h prior to ingesting 18.5 x 104 Bq of 14C-urea cocktail orally. Breath samples were collected after 20 min by asking them to blow into a hyamine solution and measurements were read in a scintillation counter. RESULTS: Fifty out of 51 patients (98%) with gastric cancer were positive on the 14C-urea breath test compared to 29 patients (61%) who were positive on histology. There was no association between sex, age or tumour site, stage, differentiation, Lauren type and H. pylori status. The test was negative in one patient with cardial tumour in which histology of the resected specimen was also negative for the bacteria. CONCLUSIONS: Active H. pylori infection is highly prevalent in gastric cancer in a South-East Asian population. The 14C-urea breath test is a highly sensitive method for detecting the presence of H. pylori even in gastric adenocarcinoma irrespective of the stage.

Adenocarcinoma↗

PubMed1997

The in vitro effect of vitamin D3 analogue EB-1089 on a human prostate cancer cell line (PC-3).

OBJECTIVE: To determine the effect of vitamin D3 analogue (EB-1089) on the growth and proliferation of a prostate cancer cell line (PC-3). MATERIALS AND METHODS: PC-3 cells (10(4) cells per well) were plated into 24-well tissue culture plates. After 24 h, the culture medium was replaced with one containing the vitamin D3 analogue EB-1089; a control treatment using only replacement medium was conducted in parallel. Cell proliferation was measured by the incorporation of 3H-thymidine 7 and 12 days after the addition of the vitamin D3 analogue. Cells were precipitated with 5% trichloroacetic acid and the radioactivity determined using a scintillation counter. Each experiment was performed at least five times. RESULTS: There was a significant dose-dependent inhibition of cell growth after 7 and 12 days of treatment with EB-1089, varying from 40 to 70% of the 3H-thymidine incorporation by controls, respectively. The maximum inhibition occurred with 0.1 micromol/L EB-1089 on day 7 and day 12 (both P < 0.01). Longer incubation times appeared to have a greater effect when higher concentrations of EB-1089 were used. CONCLUSION: These in vitro studies have shown that the vitamin D3 analogue EB-1089 can significantly reduce the growth rate of the prostate cancer cell line PC-3. This would support the hypothesis that deficiency of vitamin D increases the risk of prostate cancer and further in vivo testing of vitamin D is warranted for its potential role in active therapy.

Antineoplastic Agents↗

PubMedDate not supplied

Stability of platelet surface antigens during storage.

We measured changes in A, B, 2H, PlA1, and HLA Class I antigens on human platelets stored as routine platelet concentrates (PCs) in 50 to 60 ml of citrate-phosphate-dextrose-adenine (CPDA-1) plasma in polyolefin (PL 732) bags at 22 degrees C with continuous cartwheel rotation. Samples were obtained at 1, 3, 5, and 10 days of storage; incubated with human IgG anti-A, -B, -HLA and -PlA1; incubated with mouse monoclonal 125I-labeled anti-human IgG; centrifuged through phthalate ester oils; and assayed in a gamma scintillation counter. Additionally, group O platelets were analyzed using 125I-labeled IgM mouse monoclonal anti-Type 2H. Mean values for molecules of Ig bound per platelet showed that platelet surface antigens A, B, 2H, PlA1, and HLA Class I showed no significant change during 10-day storage as routine PCs in CPD-A1 in PL 732 bags. Identical radioassays were performed with platelets incubated at 22 degrees C in plastic test tubes for 24 hours in homologous plasma from donors negative for the respective antigens and in a variety of artificial media with albumin and lipids. No significant changes occurred in any of the surface antigens, except for the loss of approximately 50 percent of the blood group A antigen from platelets stored in O plasma or in albumin media. These data indicate that HLA, PlA1, and type 2H structures do not readily dissociate from the platelet membrane during storage, while some blood group A antigens, presumably acquired passively from the plasma, will elute from the platelet under certain conditions. Routine storage conditions are unlikely to alter the immunogenicity of platelets due to a loss of antigen expression.

Antibodies, Monoclonal↗

PubMed1985

[Separate measurements of compact and spongy bone density using a transverse rotation scanner. Determination of mineral content of the radius using a least squares algorithm].

The absorption profile of the distal forearm, which depends on bone mineralisation, was measured using a high resolution microcomputer-controlled transverse rotational scanner with a tightly collimated I-125 photon source and a scintillation counter. Reconstruction of the anatomical structures within the measured area occurred in two stages. Subsequently the linear attenuation coefficient for soft tissues, compacta and spongiosa was obtained by a "least-square" algorithm. The absorption coefficient of the compacta and spongiosa provided a measure of bone mineralisation. Correlation between the reconstructed images and the calculated results and measurements was tested by calculation. Ten measurements of a model and of in vivo bones resulted in a coefficient of variation of 1.8% and 3.3% for the compacta and 2.5% and 3.8% for the spongiosa. Relative deviation from the standard varied from +1.3% to -1.0%, depending on mineral content. This new, technically simple procedure for the separate determination of the compacta and spongiosa in the distal radius is useful for the early recognition of changes in bone mineralisation which are usually apparent first in the spongiosa.

Bone and Bones↗

PubMed1972

A new micromethod for evaluating lymphocyte responses to phytohemagglutinin: quantitative analysis of the function of thymus-dependent cells.

We have developed a new micromethod for testing phytohemagglutinin stimulation of human lymphocytes. 50 mul of peripheral blood is incubated at 37 degrees C directly, without cell separation, with 50 mul of tissue culture medium containing 50mug of phytohemagglutinin for 24 hr. Then, 0.5 muCi of tritiated thymidine in 50 mul of tissue culture medium is added and incubated for an additional 16 hr. After incubation, erythrocytes are selectively lysed in distilled water, and white blood cells are trapped quickly on a Millipore filter. The radioactivity of the filter is then assessed by a scintillation counter. The requirement of extremely small amounts of blood and a short incubation time are advantages. Further, this method provides a most useful evaluation of thymusdependent cell populations in man and experimental animals and, for the first time, this method provides the possibility of quantitating the deficiency of thymus-dependent cells.

Adolescent↗

PubMed1984

A quantitative dot-immunobinding assay for proteins using nitrocellulose membrane filters.

An immunoassay method is described for the quantitative determination of synapsin I (protein I) and of a 36,000-dalton membrane protein from rat brain synaptic vesicles. The samples are spotted on nitrocellulose membrane filters, incubated sequentially with specific antibodies and 125I-labeled protein A, and assayed for radioactivity in a gamma scintillation counter. Conditions have been established to prevent losses of protein from the sheets during processing, to quench background radioactivity, and to adjust the sensitivity to the range desired. A large number of samples can be handled in parallel. The assay does not require iodination of the antigen and is accurate even with crude tissue samples. Standard curves were linear over a 20- to 50-fold range. The sensitivity of the method is such that 10 pmol of synapsin I and 50 ng of total vesicle membrane protein could be measured with accuracy. The method should prove useful for a wide range of proteins.

Animals↗

PubMed1997

Mechanisms of lymphocyte adhesion to cultured human corneal epithelial cells.

PURPOSE: The authors studied the adhesion mechanisms between peripheral blood lymphocytes (PBL) and cultured human corneal epithelial (HCE) cells to investigate the lymphocyte interaction with corneal epithelial cells in the corneal immune response. METHODS: First, the authors examined the expression of intercellular adhesion molecule (ICAM)-1 or lymphocyte function-associated antigen (LFA)-3 on the normal human corneal epithelium and cultured HCE cells by an immunostaining technique and flow cytometry. Effects of inflammatory cytokines such as interferon (IFN)-gamma and tumor necrosis factor (TNF)-alpha, on ICAM-1 or LFA-3 expression on cultured HCE cells were also examined. Second, the authors performed an adhesion assay with 51Cr-labeled monocyte-depleted PBL from normal, healthy volunteers and cultured HCE cells, with and without treatment of IFN-gamma or TNF-alpha in 96-well-plates for 1 hour at 37 degrees C in 5% CO2. After unbound PBL were removed, the radioactivity of the sample in each well was counted with a scintillation counter. In addition, the authors evaluated the blocking effects of monoclonal antibodies (mAbs) on the adhesion of PBL to the cultured HCE cells. RESULTS: ICAM-1 expression was not detected in the normal human corneal epithelium. However, the expression of ICAM-1 was detected on the cultured HCE cells with Dulbecco's Modified Eagle Medium supplemented with 10% fetal bovine serum. In addition, both IFN-gamma and TNF-alpha increased ICAM-1 expression on the cultured HCE cells dramatically. LFA-3 expression was detected in all cell layers of the normal human corneal epithelia. Neither IFN-gamma nor TNF-alpha had any effect on LFA-3 expression on the cultured HCE cells. The PBL adhesion to the HCE cells with and without treatment of IFN-gamma or TNF-alpha was blocked dominantly by anti-ICAM-1 or anti-LFA-1 alpha mAb. Anti-LFA-3 mAb also blocked the PBL adhesion but had less blocking effect than anti-ICAM-1 or anti-LFA-1 alpha mAb. Anti-very late activation antigen beta, or anti-human leukocyte antigen (HLA)-class I or HLA-class II mAb had no effect on the PBL adhesion to the HCE cells. The adhesion percentile of the PBL applied to the HCE cells pretreated with IFN-gamma or TNF-alpha showed a dose-response curve dependent on the concentration of these cytokines. CONCLUSIONS: The results in the present study demonstrate that (i) adhesion of lymphocytes to HCE cells could be mediated by the LFA-1-ICAM-1 pathway and/or the CD2-LFA-3 pathway; (ii) the LFA-1-ICAM-1 pathway could be crucial in lymphocyte adhesion to HCE cells; (iii) IFN-gamma or TNF-alpha exerts an enhancing effect not only on the ICAM-1 expression on HCE cells but also on the adhesion of lymphocytes to HCE cells.

Antibodies, Monoclonal↗

PubMed1999

Intravitreal pharmacokinetics in rabbits of the foscarnet lipid prodrug: 1-O-octadecyl-sn-glycerol-3-phosphonoformate (ODG-PFA).

PURPOSE: To evaluate the intraocular distribution and metabolism of the lipid prodrug of foscarnet, 1-O-octadecyl-sn-glycerol-3- phosphonoformate (ODG-PFA), following intravitreal administration. METHODS: Twenty rabbits received ODG-[14C]PFA intravitreal injection, yielding 0.632 mM resultant intravitreal concentration. Two animals per group were sacrificed at different intervals post-injection. The drug levels in ocular tissues were determined with counting the radioactivity by Tracor Mark III Liquid Scintillation Counter. Four rabbits were used for analysis of the drug metabolism in vitreous by lipid extraction technique. RESULTS: The drug level in vitreous was 526 microM at day one and 227 microM at the fifth week. The vitreous half life was approximately four to five weeks. The retinal level of the drug was 292 microM at day one, 75 microM at the fifth week and 32 microM at the tenth week, which was still more than ten times higher than the IC90 against HCMV. Lipid extraction analysis showed that, in vivo, both ODG-PFA and PFA were present in vitreous, but in in vitro incubations with vitreous, ODG-PFA conversion to PFA was negligible. CONCLUSION: ODG-PFA possesses a long vitreous half life and sustained high drug level in retina. The vitreous did not metabolize drug but acted as a drug reservoir. Intravitreal liposomal ODG-PFA may be expected to be a long acting potent local therapy for CMV retinitis.

Animals↗

PubMed2001

Inhibition of cholesteatomatous bone resorption with pamidronate disodium.

Bone destruction is known to be an important cause of complications in chronic cholesteatomatous otitis media. A strategy that blocks localized bone resorption may prevent the progression of the disease. The bisphosphonate drug pamidronate is known to inhibit bone resorption and has been used in the treatment of Paget's disease and osteoporosis. The aim of this study was to investigate the effect of pamidronate on the inhibition of bone resorption in cholesteatoma using a neonatal rat calvarial culture system. Radioactive calcium was subcutaneously injected into pregnant rats. Neonatal calvariae were harvested after i.p. injection of pamidronate disodium to neonatal rats and culture supernatants of cholesteatoma keratinocytes were then added to the calvarial culture media. Radioactive calcium release was measured using a beta-ray scintillation counter. The percentage of calcium release was significantly higher in cholesteatoma culture supernatant than in Dulbecco's modification of Eagle's medium. The percentage calcium release in cholesteatoma culture supernatant was significantly lower with the high dose of pamidronate than with the low dose. These results suggest that pamidronate can inhibit the bone resorption caused by cholesteatoma. This study suggests a possible application for pamidronate in the prevention of cholesteatomatous bone destruction.

Animals↗

PubMed1976

In vitro studies on the use of penicillamine with tartar emetic against Schistosoma mansoni worms.

In vitro studies were carried out to test Sb125 tartar emetic (T.E.) in concentrations of 75, 100, 125, 150 and 200 mug/ml of rabbit serum and these concentrations together with penicillamine in ratios ranging from 1:1 to 1:6 for their effect on the motility and antimony uptake by Schistosoma mansoni worms. The motility was observed microscopically every half hour for six hours and the Sb125 content was measured by a scintillation counter at one hour intervals for five hours. Results indicate that the ratio in which penicillamine is used with T.E. is very important. The antimony uptake by the worm is reduced, and the onset of T.E. action is delayed when it is used with penicillamine in a ratio exceeding 1:2.

Animals↗

PubMed1975

The dynamics of diquat in a model eco-system.

Muskelung (Esox-masquinongy chiensis) fry were used in a 96 hour toxicity study with diquat and simazine. Although the death of sufficient control fish invalidated the test as a whole, some interesting observations were made. At the end of 48 hours 4 out of 10 fish had died in the control tank and 8 had died in the simazine tank while all 10 diquat-treated fish appeared healthy. Two model eco-systems with components from Chautauqua Lake, N.Y. were constructed in 20 gallon glass aquaria to trace the movement of 14C labeled diquat. After activity had reached near background levels in the water from the test tank, fish, plants, sediments and snails were counted in a liquid scintillation counter to discover the fate of diquat within the system. The concentration of diquat was found to be highest in sediments, followed by fish tissue, snail parts, with plants having the lowest measured concentration.

Animals↗

PubMed1998

Influence of the phosphate balance on the activity distribution of 99mTc-hydroxy-methylene diphosphonate. Experimental studies in the mouse.

OBJECTIVE: The purpose was to determine whether changes in the phosphate balance have an influence on the distribution of bone-seeking radiopharmaceuticals. MATERIAL AND METHODS: The biodistribution of 99mTc-HDP in mice, intravenously administered under varying conditions, was assessed by removing different organs and estimating their activity in a scintillation counter. Some experiments were also performed with 99mTc-MDP and 99mTc-DPD. RESULTS: After 1 h and 18 h on phosphate-enriched drinking water, the mice showed a strongly increased uptake in all organs/tissues representing background activity and a decrease in the bone uptake. This pattern changed with time. After 6-8 days of phosphate load, we saw a more favourable distribution with a reduction of the background and whole-body activity. Administration of hPTH 1-34 gave rise to an activity distribution similar to that after 6-8 days on phosphate-enriched water. Changing the phosphate balance had less obvious effects on the distribution of 99mTc-MDP and 99mTc-DPD. CONCLUSION: The activity distribution of bone-seeking radiopharmaceuticals in the mouse is affected by the phosphate balance. The mechanism behind this finding is unknown but it may be partially mediated by PTH. It is possible that changes in the phosphate balance, induced by pharmaceuticals or by dietary changes, may affect the image quality at bone scintigraphy.

Animals↗

PubMed1987

Reduction of 141Ce absorption in suckling rats.

The influence of diet or its ingredients on 141Ce absorption and retention was investigated in six-day-old rats. Animals were fed over 8h with cow's milk, rat diet or a mixture of rat diet ingredients (fish meal, sunflower meal, alfalfa, cane molasses and premix) labelled with 141Ce. Whole-body radioactivity was determined in a double crystal scintillation counter every 24 h over a six-day period. Gut, liver, kidney and femur retention and cerium distribution in the gut was determined at the end of the experiment. Compared to milk diet, administration of rat diet or ingredients caused respectively 3 and 7.5 times lower whole body retention. Carcass retention was reduced by rat diet or ingredients 2-3 times and intestinal retention 3 and 8 times respectively. Irrespective of the dietary treatment the main site of cerium intestinal retention was the ileum. Our present results indicate that some compounds of rat diet might be considered as a means of reducing cerium absorption and intestinal retention in the very young.

Animal Feed↗

PubMed1990

HTO oral administration in mice. I: Threshold dose rate for haematopoietic death.

Tritiated water in various concentrations was orally administered continuously to (C57BL/6N and C3H/He)F1 female mice in a closed animal chamber. Tritium radioactivity in various organ tissues was measured periodically after initiating tritiated water intake using an automatic sample combustion system and a liquid scintillation counter. After 7 days the specific radioactivity reached a plateau. These data allowed absorbed organ doses to be estimated. Within a range of 1.48 x 10(11) to 5.92 x 10(11) Bq/dm3 as the concentration of tritiated water in drinking water, the time of death after initiating the administration was about 2 weeks, a typical time for haematopoietic death. A linear relationship of times of death with tritiated water concentrations in drinking water was observed, on a log-log scale, between 1.85 x 10(10) Bq/dm3 and 1.48 x 10(11) Bq/dm3. At concentrations lower than 9.25 x 10(9) Bq/dm3, mice no longer died from haematopoietic failure. We conclude, therefore, that there should be a threshold dose rate for haematopoietic death.

Animals↗

PubMed2004

Mathematical modeling of RDX and HMX metabolism in poplar (Populus deltoides x Populus nigra, DN34) tissue culture.

Three mathematical models were developed based on a fate study as an approach to define transformation pathways of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) within plant cells. [U-14C]RDX and [U-14C]HMX were added in Murashige and Skoog (MS) liquid media containing Populus deltoides x P. nigra (DN34) tissue cultures. Radioactivity of samples was analyzed using HPLC, a bio-oxidizer and liquid scintillation counter. Based on information collected, transformation pathways of nitramine compounds were fitted with the raw data obtained and using a modified "green liver" model. Ordinary differential equations were developed and simulations were performed with MicroMath Scientist version 2.0 (MicroMath Inc., St. Louis, MO, USA). The three models, with different sequential transformation processes, were tested in order to support the raw data (model I) and the assumptions of the modified "green liver" model (models II and III). The results showed a high correlation between the collected data and the simulated concentrations for all models. Thus, the simplest model developed (model I) is the best model description of these particular results. The results obtained suggest that the principle of parsimony should be applied. The "green liver"-based models also demonstrated a reliable approach for the investigation of degradation pathways of nitramines within plant cells.

Azocines↗

PubMed1967

Circadian phase relationships of thymidine-3H uptake, labeled nuclei, grain counts, and cell division rate in rat corneal epithelium.

Significant differences in the uptake of thymidine-(3)H, percentage of labeled cells, numbers of grains per labeled nucleus, and mitotic rate were noted in rat corneal epithelium along a 24-hr time scale. These were demonstrated by injecting subgroups of five animals every hour during a 24-hr period with thymidine-(3)H, sacrificing them 2 hr later, and analyzing the corneal epithelium by scintillation counter and radioautographic techniques. The increase in uptake during specific periods of the 24-hr time scale is attributed to an acceleration in the rate of DNA synthesis by individual cells and to an increase in the percentage of cells in the population actively synthesizing DNA.

Animals↗

PubMed1991

Prevention of radioactive indicator and viral particle transmission with an ointment barrier.

OBJECTIVE: To determine the efficacy of a lanolin-based gel in preventing radioactive particle and viral penetration. DESIGN: Paired, stacked filter discs were held in a stainless steel support, and the gel was applied manually to the upper surface of the upper filter. Indicator solution containing either radioactive viral particles (3H-labeled simian virus 40 or 3H-labeled woodchuck hepatitis virus) or 20 microliters or 100 microliters of 32P-labeled radioactive compounds of much lower molecular weight then were applied to the upper filter. The filter discs were separated after 30 minutes, and the lower disc was examined for radioactivity in a liquid scintillation counter. RESULTS: Transmission of radioactive particles was statistically significantly reduced by the application of the ointment on the upper filter (from 6.7 +/- 0.1 x 10(5) counts per minute [cpm] to 88 +/- 38 cpm). Transmission of both labeled viral particles also was reduced to a similar degree. CONCLUSIONS: Application of protective ointment to the filters significantly reduces transmission of radioactive viral particles and smaller radioactive compounds through filter discs. Use of this ointment may offer similar mechanical protection against the transmission of viruses between patient and healthcare provider.

Equipment Contamination↗

PubMed1996

Transepithelial transport of ascorbic acid by the isolated intact ciliary epithelial bilayer of the rabbit eye.

The purpose of these experiments was to test whether the isolated intact epithelial bilayer derived from rabbit ciliary processes transports ascorbic acid and to what degree the transport rate in vitro corresponds to the in vivo process. The intact ciliary epithelial bilayer of the rabbit eye isolated by perfusion was mounted in a particularly constructed Ussing type chamber. Fluxes were measured by additions of 14C ascorbate to the hemichamber on either the pigmented epithelium (PE) or the nonpigmented epithelium (NPE) side where equal concentrations of ascorbate from .02 to 2.0 mM were present. Samples were taken at intervals thereafter and counted in a liquid scintillation counter. The experiments were done under short circuit conditions to avoid the possible influence of fluctuating currents upon the movement of ascorbate. Like the earlier iris ciliary body preparations, separation of ascorbate fluxes is also done by the isolated intact ciliary epithelial bilayer, and the transport of ascorbic acid proceeds by saturation kinetics. The uptake process is accomplished entirely by the pigmented epithelium (PE). The Km of the process is 0.97 mM, and Vmax was valued at 130 nM/L/hr. Thus, assuming an aqueous flow rate of 2 microliters/min, the transfer of ascorbic acid across the bilayer occurs at a rate required to maintain the ordinary millimolar concentration of ascorbic acid in the aqueous humor found in vivo.

Animals↗