The accuracy of helium ion CT based particle therapy range prediction: an experimental study comparing different particle and x-ray CT modalities.

This work provides a quantitative assessment of helium ion CT (HeCT) for particle therapy treatment planning. For the first time, HeCT based range prediction accuracy in a heterogeneous tissue phantom is presented and compared to single-energy x-ray CT (SECT), dual-energy x-ray CT (DECT) and proton CT (pCT). HeCT and pCT scans were acquired using the US pCT collaboration prototype particle CT scanner at the Heidelberg Ion-Beam Therapy Center. SECT and DECT scans were done with a Siemens Somatom Definition Flash and converted to RSP. A Catphan CTP404 module was used to study the RSP accuracy of HeCT. A custom phantom of 20 cm diameter containing several tissue equivalent plastic cubes was used to assess the spatial resolution of HeCT and compare it to DECT. A clinically realistic heterogeneous tissue phantom was constructed using cranial slices from a pig head placed inside a cylindrical phantom (ø150 mm). A proton beam (84.67 mm range) depth-dose measurement was acquired using a stack of GafchromicTM EBT-XD films in a central dosimetry insert in the phantom. CT scans of the phantom were acquired with each modality, and proton depth-dose estimates were simulated based on the reconstructions. The RSP accuracy of HeCT for the plastic phantom was found to be 0.3 ± 0.1%. The spatial resolution for HeCT of the cube phantom was 5.9 ± 0.4 lp cm-1for central, and 7.6 ± 0.8 lp cm-1for peripheral cubes, comparable to DECT spatial resolution (7.7 ± 0.3 lp cm-1and 7.4 ± 0.2 lp cm-1, respectively). For the pig head, HeCT, SECT, DECT and pCT predicted range accuracy was 0.25%, -1.40%, -0.45% and 0.39%, respectively. In this study, HeCT acquired with a prototype system showed potential for particle therapy treatment planning, offering RSP accuracy, spatial resolution, and range prediction accuracy comparable to that achieved with a commercial DECT scanner. Still, technical improvements of HeCT are needed to enable clinical implementation.

Inhibition of monocarboxylate transporter-4 depletes stem-like glioblastoma cells and inhibits HIF transcriptional response in a lactate-independent manner.

Hypoxic regions are frequent in glioblastoma (GBM), the most common type of malignant adult brain tumor, and increased levels of tumor hypoxia have been associated with worse clinical outcomes. To unmask genes important in hypoxia, we treated GBM neurospheres in hypoxia and identified monocarboxylate transporter-4 (MCT4) as one of the most upregulated genes. To investigate the clinical importance of MCT4 in GBM, we examined clinical outcomes and found that MCT4 overexpression is associated with shorter patient survival. Consistent with this, MCT4 upregulation correlated with the aggressive mesenchymal subset of GBM, and MCT4 downregulation correlated with the less aggressive G-CIMP (Glioma CpG Methylator Phenotype) subset of GBM. Immunohistochemical analysis of tissue microarrays confirmed that MCT4 protein levels were increased in high-grade as compared with lower-grade astrocytomas, further suggesting that MCT4 is a clinically relevant target. To test the requirement for MCT4 in vitro, we transduced neurospheres with lentiviruses encoding short-hairpin RNAs (shRNAs) against MCT4, resulting in growth inhibition of 50-80% under hypoxia in two lines. MCT4 knockdown was associated with a decreased percentage of cells expressing the stem-cell marker CD133 and increased apoptotic fraction. We also found that flow-sorted CD133-positive cells had almost sixfold higher MCT4 levels than CD133-negative cells, suggesting that the stem-like population might have a greater requirement for MCT4. Most importantly, MCT4 silencing also slowed GBM intracranial xenograft growth in vivo. Interestingly, whereas MCT4 is a well-characterized lactate exporter, we found that both intracellular and extracellular lactate levels did not change following MCT4 silencing, suggesting a novel lactate export-independent mechanism for growth inhibition in GBMs. To identify this potential mechanism, we performed microarray analysis on control and shMCT4-expressing neurospheres and found a dramatic reduction in the expression of multiple Hypoxia-Inducible Factor (HIF)-regulated genes following MCT4 knockdown. The overall reduction in HIF transcriptional response was further validated using a hypoxia response element (HRE)-dependent green-fluorescent protein (GFP) reporter line.

Experimental demonstration of a synthetic aperture compression scheme for multi-Petawatt high-energy lasers.

We present the experimental demonstration of a subaperture compression scheme achieved in the PETAL (PETawatt Aquitaine Laser) facility. We evidence that by dividing the beam into small subapertures fitting the available grating size, the sub-beam can be individually compressed below 1 ps, synchronized below 50 fs and then coherently added thanks to a segmented mirror.

Erythritol: an interpretive summary of biochemical, metabolic, toxicological and clinical data.

A critical and comprehensive review of the safety information on erythritol was undertaken. Numerous toxicity and metabolic studies have been conducted on erythritol in rats, mice and dogs. The toxicity studies consist of long-term feeding studies conducted to determine carcinogenic potential, intravenous and oral teratogenicity studies to determine the potential for effects on the foetus, oral studies in which erythritol was administered over one or two generations to determine the potential for reproductive effects, and studies in bacterial and mammalian systems to determine mutagenic potential. The majority of the safety studies conducted were feeding studies in which erythritol was mixed into the diet at concentrations as high as 20%. The metabolic studies in animals have shown that erythritol is almost completely absorbed, not metabolized systemically and is excreted unchanged in the urine. The safety studies have demonstrated that erythritol is well tolerated and elicits no toxicological effects. The clinical program for erythritol involved a series of single-dose and repeat-dose, short-duration studies which have been used to investigate the human correlates to the physiological responses seen in the preclinical studies. The clinical studies showed erythritol to be well tolerated and not to cause any toxicologically relevant effects, even following high-dose exposure. Erythritol administered orally to humans was rapidly absorbed from the gastrointestinal tract and quantitatively excreted in the urine without undergoing metabolic change. At high oral doses, urinary excretion accounted for approximately 90% of the administered dose with minimal amounts appearing in the faeces. A comparison of the human and animal data indicated a high degree of similarity in the metabolism of erythritol and this finding supports the use of the animal species used to evaluate the safety of erythritol for human consumption. It can be concluded, based on the available studies that erythritol did not produce evidence of toxicity.

Expression of chromosomally inserted bacillus thuringiensis israelensis toxin genes in bacillus sphaericus

Bacillus thuringiensis israelensis delta-endotoxin genes were inserted into transposon Tn917 in plasmid pTV51Ts and cloned into the chromosome of Bacillus sphaericus 2362. Many of the transformants reacted with antibody to the 135-, 128-, 65-, and 28-kDa B.t.israelensis toxin proteins and were approximately 10 times more toxic to A. aegypti larvae than the untransformed host. Some of the transformants differed physiologically and morphologically from the wild-type B. sphaericus. The toxicity of the transformed phenotype was maintained through many transfers in the absence of selective pressure. Copyright 1998 Academic Press.

Assessment of DNA damage induced in vitro by etoposide and two fungicides (carbendazim and chlorothalonil) in human lymphocytes with the comet assay.

The effects of two fungicides (carbendazim and chlorothalonil) on the induction of DNA damage in human peripheral blood lymphocytes (human PBL) have been investigated using the single cell gel electrophoresis assay (SCGE assay or comet assay) immediately after a 1-h treatment and after a 24-h post-treatment incubation. The assessment of etoposide (an effective antitumour agent) effects on human PBL in terms of cell viability and dose-DNA damage relationships was made and etoposide selected as a positive control. The results indicate that etoposide induces significant (p < 0.01) dose-dependent DNA damages for concentrations at which the loss of cell viability is low. After a 24-h recuperation period, all observed DNA damages has disappeared. With SCGE assay performed after a 1-h treatment, similar positive results were observed with chlorothalonil alone or in association with carbendazim, without any loss of cell viability. However, a dramatic loss of cell viability was measured after 24 h and was associated with a large proportion of highly damaged cells. In contrast, carbendazim was not cytotoxic on human PBL and did not induced DNA damage using the SCGE assay either immediately after treatment or after a 24-h post-treatment incubation. These results point to the necessity of an adequate evaluation of immediate and long-term cytotoxicity of compounds that are to be assessed by the SCGE assay.

[Second opinion--from the medical insurance viewpoint]. / Second opinion--aus versicherungsmedizinischer Sicht.

The history of the initial second opinion programmes is summarized. The original expectations in these programmes and their goals are stated. Some studies on second opinion programmes showed cost-savings in health care expenditure. However, there are no valid studies proving that the health care budget had been decreased. Improvements in the patient doctor relationship were demonstrated although improvements in the quality of patient care through second opinion programmes could not be ascertained. This lack of consistency reflects the limited reliability of clinical judgements. J. R. Clarke demonstrated that analysing the decision path leading to a surgical procedure was superior to second opinion programmes in achieving a correct surgical therapy. The Swiss Accident Insurance Company (SUVA) is organized in regionally assigned physicians and a dense network of administrative offices providing proficient advisory (support?) services to physicians in practice. Additional programmes are therefore not advocated and a mandatory confirmation of the need for certain surgical indications through second opinion programmes is not required. Instead, we advise to employ decision analysis in order to strengthen the foundation of clinical judgments and to improve the selection of therapies. It is proposed that elaborating medical-surgical decision paths should include psychological, socio-economical and cultural issues affecting the patient's welfare, in addition to anatomical and technical aspects determining the therapeutic feasibility.

Serum galactosyltransferase activities in newborn children and pregnant women.

We have compared serum galactosyltransferase activity in pregnant women and in newborn children. Subjects in this study were 75 women at different stages of pregnancy and 60 newborns, including premature infants. Activity ratios in pregnant women are based on the period of gestation, expressed in weeks of amenorrhea. Average values were 265 nmol/h/ml for up to 12 weeks of amenorrhea, 369 from 13 to 28 weeks and 483 over 28 weeks versus 232 nmol/h/ml for non-pregnant women. In infants, galactosyltransferase activity decreased with increasing age from conception, but the activity level was always much higher in newborns than in women at the ninth month of pregnancy. We discuss the origin of the enzyme in these various samples.

Biological markers and ovarian carcinomas: galactosyltransferase, CA 125, isoenzymes of amylase and alkaline phosphatase.

We present a comparative study of several biological markers (galactosyltransferase, CA 125, isoenzymes of amylase and alkaline phosphatase) with a view to ovarian carcinoma follow-up. Serum samples were obtained from a population of 75 patients under clinical observation. After a minimum 18-months period, we assessed the prognostic value of the markers. No marker permits the detection of discrete, evolving carcinomas. CA 125 is the marker that gives the best results, particularly in terms of sensitivity. Galactosyltransferase has a lower sensitivity except in the case of endometrioid carcinomas. Simultaneous analysis with CA 125 and galactosyltransferase results in no decisive improvement, other than greater precision in unfavourable prognoses. Isoenzymes of amylase and alkaline phosphatase are of no interest in the follow-up of such carcinomas.

Cloning and expression of Bacillus thuringiensis israelensis delta-endotoxin DNA in B. sphaericus.

Bacillus thuringiensis israelensis delta-endotoxin genes were cloned into Bacillus sphaericus 2362, producing stable transformants reacting with antibody to the 28- and 65-kDa B. thuringiensis israelensis crystal proteins and approximately 10 times more toxic to Aedes mosquito larvae than the original host strain. The LC50 after 48 hr of exposure of Aedes larvae to the most active transformed clone was 0.19 microgram/ml, compared with an LC50 of 1.9 microgram/ml for B. sphaericus 2362 and less than 0.1 microgram/ml for B. thuringiensis israelensis. The cloning vector, plasmid pPL603E, was also effective in transforming B. subtilis 1E20 with B. thuringiensis israelensis DNA, producing highly toxic clones with less stable gene expression than the clones of B. sphaericus.

[Localization and modulation of galactosyltransferase during in vitro proliferation of a human ovarian adenocarcinoma cell line]. / Localisation et modulation de la galactosyltransférase au cours de la prolifération in vitro d'une lignée cellulaire issue d'un adénocarcinome ovarien humain.

A cell line, IGROV1, originating from a human ovarian cancer, releases a galactosyltransferase activity in its culture medium during proliferation. The proliferating IGROV1 cells appear as two populations: some cells grow in floating clusters whereas the greater part of them adhere to the culture substrate. The study of galactose transfer by intact cells onto an exogenous glycoprotein acceptor (ovomucoid) shows the presence of surface-associated galactosyltransferase onto the two cellular sub-populations. Opposite to intracellular activity, surface-associated and released galactosyltransferase activities depend on cellular adhesion and proliferation.

A simple serum galactosyltransferase assay method suitable for routine use.

UDP-Galactose: N-acetylglucosaminyl glycoprotein beta 1-4 galactosyltransferase (GT) catalyzes the transfer of galactose to N-acetylglucosamine from UDP-[3H]Gal. The uncharged reaction product (tritiated N-acetyllactosamine) is separated from the unreacted UDP-[3H]Gal by ion-exchange chromatography. The major advantage of this method is its rapidity compared to other isotopic techniques.

Alteration in isoenzyme patterns of serum galactosyltransferase activity in ovarian cancer patients: preliminary results.

Isoelectric focusing on agarose gel was used to separate the isoenzymes of serum galactosyltransferase (uridine diphosphogalactose: N-acetylglucosaminyl galactosyltransferase, EC 2.4.1.22) from 8 healthy women, and 11 ovarian cancer patients of whom 4 were in clinical remission. In all cases, we found 7 major peaks with isoelectric points ranging from 4.0-5.4. The most acidic peaks were preferentially elevated in the tumor-bearing patients, particularly the peak with pI 4.44.

Serum galactosyltransferase activity with three acceptors in ovarian cancer patients.

Several laboratories have demonstrated the usefulness of serum galactosyltransferase as a biological marker for ovarian neoplasms. However, contradictory results have been published recently, which might be partially explained by differences in methodology. We thus decided to measure serum galactosyltransferase activity in patients with ovarian cancer and benign gynecological diseases using three different assay systems. A very good correlation was obtained between the results of these assays. Furthermore, we confirm that serum GT is frequently elevated in cancer patients, and is of potential value for their follow-up.

[Comparative study of various technics for the determination of human serum galactosyltransferase]. / Etude comparative de différentes techniques de dosage de la galactosyltransférase sérique humaine.

We have compared three assays for serum galactosyltransferase activity, which use ovomucoïd, asialo agalactofetuin and free N-acetylglucosamine respectively as exogenous acceptors. A very good correlation between the three assays is obtained, for the whole range of GT activity. When the methods are compared to one another, the slopes of the regression lines are similar whether the sera are collected from healthy controls, pregnant women, or women suffering from benign gynecologic diseases or ovarian neoplasms. The methods which uses free N-acetylglucosamine as acceptor is rapid, cheaper and easier to perform.

Isoenzymatic patterns of human galactosyltransferase from normal and cancer patients.

Chromatofocusing revealed the high heterogeneity of human serum galactosyltransferase with regard to isoelectric point. At least 11 major peaks of activity were observed for normal sera, at the following pH elutions: 4.3, 4.4, 4.6, 4.77, 5.0, 5.15, 5.45, 5.8, 6.35, 6.65, and 6.9. In addition, a fraction of the activity was eluted above pH 7. Some of those peaks were also present in sera from cancer patients, but almost all the peaks in the 7.4-5.4 pH range had disappeared. Alpha-lactalbumin affinity chromatography strongly modified the chromatofocusing pattern of galactosyltransferase from an ascitic fluid of a cancer patient.

[Separation of isoenzymatic forms of human serum galactosyltransferase by chromatofocusing and isoelectric focusing. Application to cancerology]. / Séparation des formes isoenzymatiques de la galactosyltransférase du sérum humain par chromatofocalisation et focalisation isoélectrique. Application à la cancérologie.

Chromatofocusing is used to separate the multiple isoenzyme forms of human serum galactosyltransferase. At least 11 major peaks of activity are observed in normal sera, which are eluted between pH 4.3 and 6.9; a fraction of activity is eluted above pH 7.0. The normal patterns are compared with those obtained with sera from cancer patients and with an ascitic fluid. Chromatofocusing appears as resolutive as agarose isoelectric focusing.

[Determination of human serum galactosyltransferase using a kinetic spectrophotometric technic]. / Dosage de la galactosyltransférase du sérum humain à l'aide d'une technique cinétique spectrophotométrique.

A kinetic spectrophotometric method in which galactose transfer is coupled to the production of NADH, has been adapted to the assay of galactosyltransferase activity in human serum. Under the described conditions, the rate of NADH production is linear with regard to enzyme concentration, and directly depends upon the various biochemical factors which control galactosyltransferase activity.