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At least 325 records · Page 18Linked to original sources
PubMed1985

Ability of sera from mice treated with Ge-132, an organic germanium compound, to inhibit experimental murine ascites tumours.

Sera from C57Bl/6 mice treated orally with Ge-132 exhibited antitumour activity against Ehrlich (allogeneic) and RL male 1 (syngeneic) ascites tumours in BALB/c mice. Sera obtained from mice 24 h after Ge-132 administration displayed the greatest antitumour effect and this was dose dependent. Sera prepared from mice 12, 36, or 48 h after Ge-132 treatment had no protective effect. Circulating interferon (IFN) was induced at 24 h after administration of Ge-132 but was not detected in the sera at 12, 36, or 48 h after administration. The antiviral activity of sera from Ge-132-treated mice was inactivated by treatments with trypsin, low pH, and anti-IFN gamma antiserum. The inactivated preparations of serum IFN induced by Ge-132 did not exhibit antitumour activity when administered to tumour-bearing mice. These results suggest that antitumour activity in the sera of Ge-132-treated mice may be expressed through activities of Ge-132-induced lymphokine(s), such as IFN gamma.

Animals↗
PubMed1998

Improved quantitative electron probe X-ray microanalysis of biological cryosections using an EDS germanium detector and a super-atmosphere thin window (SuperATW).

A new Link energy-dispersive GEM detector with SuperATW window was tested for quantitative electron probe microanalysis of low calcium and sodium concentrations ([Ca], [Na]) in intracellular compartments of cardiac myocytes. We compare Ca profiles with high count statistics and similar peak area collected under the same conditions with either a Be-windowed Si and a Ge SuperATW detector. The height of the Ca peak was increased by 7%, the full width at half-maximum height was reduced by 9% with the Ge detector. The counts statistics of the Ca K alpha peak improved by 9% and the partial overlap with the K K beta peak was better deconvoluted. We calculate [Ca] and errors of the single measurement in mitochondria of guinea-pig cardiac myocytes from spectra acquired with a Si or Ge detector. For identical analysis conditions, the [Ca] were identical; however, with the Ge SuperATW detector, the calculated error of the single measurement was only 1/2.7 of that calculated from measurements with the Si detector. We compare the peak area of identical [Na] in spectra collected with the Be-windowed Si detector and Ge SuperATW detector. The peak area was significantly higher with the SuperATW Ge than with the Si detector and Be window, whereas the continuum in the range 4-10 keV was comparable, demonstrating the improved sensitivity for low atomic elements such as Na of the Ge SuperATW detector. [Na] and errors of the single measurement in mitochondria of quiescent guinea-pig cardiac myocytes were calculated from spectra acquired with the Si or the Ge detector. The use of the Ge SuperATW detector improved the detectability limit for sodium by more than 80% and reduced the error of the single measurement by a factor of 7-8.

Animals↗
PubMed1991

Modifying responses of allyl sulfide, indole-3-carbinol and germanium in a rat multi-organ carcinogenesis model.

The modifying potential of allyl sulfide (AS), indole-3-carbinol (I3C) and carboxyethylgermanium sesquioxide (GE) on lesion development was examined in a wide-spectrum initiation model. Groups 1-4 were treated sequentially with diethylnitrosamine (DEN) (100 mg/kg, i.p., single dose), N-methylnitrosourea (MNU) (20 mg/kg, i.p., four doses at days 2, 5, 8 and 11), and N,N-dibutylnitrosamine (DBN) (0.05% in drinking water during weeks 3 and 4). Groups 5-7 received vehicles without carcinogens during the initiation period. Group 8 served as the untreated control. After this initiating procedure, groups 2-7 were administered a diet containing 0.5% AS or I3C and 0.05% GE. All surviving animals were killed 40 weeks after the beginning of the experiment and the target organs were examined. The induction of GST-P+ hepatic foci in rats treated with carcinogens was significantly inhibited by treatment with all three compounds. AS treatment significantly decreased the incidence of hepatic hyperplastic nodules, adenoma of the lung and thyroid, and papillary or nodular hyperplasia of the urinary bladder. Administration of GE also significantly inhibited the development of hepatic nodules and adenoma of the lung and thyroid. However, I3C only inhibited the hyperplastic nodules of the liver. These results demonstrated that this multi-organ initiation model could be useful in confirming organ-specific modification potential and, in addition, the inhibitory effect of AS, I3C and GE on liver, lung, thyroid and urinary bladder carcinogenesis.

Allyl Compounds↗
PubMed2005

Simulation of germanium detector calibration using the Monte Carlo method: comparison between point and surface source models.

Simulation of detector calibration using the Monte Carlo method is very convenient. The computational calibration procedure using the MCNP code was validated by comparing results of the simulation with laboratory measurements. The standard source used for this validation was a disc-shaped filter where fission and activation products were deposited. Some discrepancies between the MCNP results and laboratory measurements were attributed to the point source model adopted. In this paper, the standard source has been simulated using both point and surface source models. Results from both models are compared with each other as well as with experimental measurements. Two variables, namely, the collimator diameter and detector-source distance have been considered in the comparison analysis. The disc model is seen to be a better model as expected. However, the point source model is good for large collimator diameter and also when the distance from detector to source increases, although for smaller sizes of the collimator and lower distances a surface source model is necessary.

Algorithms↗
PubMed2006

Large area germanium detector arrays for lung counting: what is the optimum number of detectors?

Using the Lawrence Livermore National Laboratory (LLNL) torso phantom to calibrate a lung counting system can lead to the conclusion that three large area (i.e. >70 mm diameter) Ge detectors will outperform a four-detector array and provide a lower MDA as a four-detector array of large area Ge detectors covers a significant portion of inactive tissue (i.e. non-lung tissue). The lungs of the LLNL phantom, which are approximately 10 cm too short compared with real lungs, also suggests that a two-detector array could be used under limited circumstances. When tested with modified lungs that are more human-like, it was found that the four-detector array showed the best counting efficiency and the lowest MDA. Fortunately, these findings indicate that, although the LLNL phantom's lungs are too short, there is no adverse impact on the calibration of a lung counter.

Computer Simulation↗
PubMed1983

Identification of 241Am in the axillary lymph nodes with an intrinsic germanium detector.

A routine measurement with two 200 mm-diameter phoswich detectors, placed one each side of the sternum, yielded an apparent lung content of 17 nCi 241Am for a subject. subject. Inspection of the data revealed that there were many more counts from the left side than from the right and that there was a greater number of Np L X rays observed, relative to the L gamma ray, than would be expected for a uniform lung distribution of 241Am. These observations suggested a shallow localised deposit in the left side of the chest. The subject's working history could not rule out an inhalation exposure, but he was known to have had a wound contaminated with Pu/Am in his left hand 16 yr previously. The wound had contained approx. 0.02-0.03 mu Ci 241Am initially, most of which was excised from the wound site after 50 days. Prompted by this knowledge we used a 50mm-diameter intrinsic Ge detector to examine the wound and relevant lymph node sites. The results demonstrated a localised deposit of 241Am in the axillary lymph nodes with approx. 1 nCi 241Am at the wound site. Subsequent measurements made with the phoswich detectors suggested that there was approx. 7 nCi 241Am in the lymph nodes with approx. 1 nCi 241Am in the liver, thereby accounting for most of the detectable 241Am contamination in the thorax.

Americium↗
PubMed2005

Temperature-induced density anomaly in Te-Rich liquid germanium tellurides: p versus sp3 bonding?

The density anomaly of liquid Ge(0.15)Te(0.85) measured between 633 and 733 K is investigated with ab initio molecular dynamics calculations at four temperatures and at the corresponding experimental densities. For box sizes ranging from 56 to 112 atoms, an 8 k-points sampling of the Brillouin zone is necessary to obtain reliable results. Contrary to other Ge chalcogenides, no sp(3) hybridization of the Ge bonding is observed. As a consequence, the negative thermal expansion of the liquid is not related to a tetrahedral bonding as in the case of water or silica. We show that it results from the symmetry recovery of the local environment of Ge atoms that is distorted at low temperature by a Peierls-like mechanism acting in the liquid state in the same way as in the parent solid phases.

Computer Simulation↗