Treatment plan modification using voxel-based weighting factors/dose prescription

Under various clinical situations, it is desirable to modify the original treatment plan to better suit the clinical goals. In this work, a method to help physicians modify treatment plans based on their clinical preferences is proposed. The method uses a weighted quadratic dose objective function. The commonly used organ-/ROI-based weighting factors are expanded to a set of voxel-based weighting factors in order to obtain greater flexibility in treatment plan modification. Two different but equivalent modification schemes based on Rustem's quadratic programming algorithms--modification of a weighting matrix and modification of prescribed doses--are presented. Case studies demonstrated the effectiveness of the two methods with regard to their capability to fine-tune treatment plans.     

Comparative genomic hybridization analysis of hepatoblastoma reveals high frequency of X-chromosome gains and similarities between epithelial and stromal components

Hepatoblastoma (HB) is the most common liver tumor in childhood and differs in its environmental risk factors and genetic background from hepatocellular carcinoma. HB is associated with inherited conditions such as familial adenomatous polyposis and Beckwith-Wiedemann syndrome, suggesting the importance of genetic abnormalities in the pathogenesis and progression of this disease. It has a very polymorphous morphology. A diverse range of cytogenetic alterations has been reported to date, the most frequent being trisomy 2 and trisomy 20. Thirty-five HB specimens from 31 patients (22 purely epithelial, 4 purely mesenchymal, 9 mixed) were examined by comparative genomic hybridization (CGH), a technique that enables us to screen the entire tumor genome for genetic losses and gains. Our aims were as follows: (1) to characterize chromosome abnormalities that appear in this tumor and (2) to identify possible differences between different histologic subtypes of HB. We found significant gains of genetic material, with very little difference in the number and type of alterations between the different histologic components of HB. The most frequent alterations were gains of Xp (15 cases, 43%) and Xq (21 cases, 60%). This finding was also confirmed by fluorescent in situ hybridization performed on nuclei extracted from 6 specimens. Other common alterations were 1p-, 2q+, 2q-, 4q-, and 4q+. We found no difference between different histologic subtypes, a finding that may be in agreement with the hypothesis of a common clonal origin for the different components. An hitherto-unreported high frequency of X chromosome gains may support the assumption that X-linked genes are involved in the development of this neoplasm.     

Gene gun bombardment-mediated expression and translocation of EGFP-tagged GLUT4 in skeletal muscle fibres in vivo

Cellular protein trafficking has been studied to date only in vitro or with techniques that are invasive and have a low time resolution. To establish a gentle method for analysis of glucose transporter-4 (GLUT4) trafficking in vivo in fully differentiated rat skeletal muscle fibres we combined the enhanced green fluorescent protein (EGFP) labelling technique with physical transfection methods in vivo: intramuscular plasmid injection or gene gun bombardment. During optimisation experiments with plasmid coding for the EGFP reporter alone EGFP-positive muscle fibres were counted after collagenase treatment of in vivo transfected flexor digitorum brevis (FDB) muscles. In contrast to gene gun bombardment, intramuscular injection produced EGFP expression in only a few fibres. Regardless of the transfection technique, EGFP expression was higher in muscles from 2-week-old rats than in those from 6-week-old rats and peaked around 1 week after transfection. The gene gun was used subsequently with a plasmid coding for EGFP linked to the C-terminus of GLUT4 (GLUT4-EGFP). Rats were anaesthetised 5 days after transfection and insulin given i.v. with or without accompanying electrical hindleg muscle stimulation. After stimulation, the hindlegs were fixed by perfusion. GLUT4-EGFP-positive FDB fibres were isolated and analysed by confocal microscopy. The intracellular distribution of GLUT4-EGFP under basal conditions as well as after translocation to the plasma membrane in response to insulin, contractions, or both, was in accordance with previous studies of endogenous GLUT4. Finally, GLUT4-EGFP trafficking in quadriceps muscle in vivo was studied using time-lapse microscopy analysis in anaesthetised mice and the first detailed time-lapse recordings of GLUT4-EGFP translocation in fully differentiated skeletal muscle in vivo were obtained.     

Factors affecting the determination of threshold doses for allergenic foods: how much is too much?

BACKGROUND: Ingestion of small amounts of an offending food can elicit adverse reactions in individuals with IgE-mediated food allergies. The threshold dose for provocation of such reactions is often considered to be zero. However, because of various practical limitations in food production and processing, foods may occasionally contain trace residues of the offending food. Are these very low, residual quantities hazardous to allergic consumers? How much of the offending food is too much? Very little quantitative information exists to allow any risk assessments to be conducted by the food industry. OBJECTIVE: We sought to determine whether the quality and quantity of existing clinical data on threshold doses for commonly allergenic foods were sufficient to allow consensus to be reached on establishment of threshold doses for specific foods. METHODS: In September 1999, 12 clinical allergists and other interested parties were invited to participate in a roundtable conference to share existing data on threshold doses and to discuss clinical approaches that would allow the acquisition of that information. RESULTS: Considerable data were identified in clinical files relating to the threshold doses for peanut, cows' milk, and egg; limited data were available for other foods, such as fish and mustard. CONCLUSIONS: Because these data were often obtained by means of different protocols, the estimation of a threshold dose was very difficult. Development of a standardized protocol for clinical experiments to allow determination of the threshold dose is needed.     

Acid phosphatases.

Acid phosphatases (APs) are a family of enzymes that are widespread in nature, and can be found in many animal and plant species. Mystery surrounds the precise functional role of these molecular facilitators, despite much research. Yet, paradoxically, human APs have had considerable impact as tools of clinical investigation and intervention. One particular example is tartrate resistant acid phosphatase, which is detected in the serum in raised amounts accompanying pathological bone resorption. This article seeks to explore the identity and diversity of APs, and to demonstrate the relation between APs, human disease, and clinical diagnosis.     

Genotoxicity of naturally occurring indole compounds: correlation between covalent DNA binding and other genotoxicity tests

3-Methylindole (3MI), melatonin (Mel), serotonin (Ser), and tryptamine (Tryp) were evaluated in vitro for their potential to induce DNA adducts, DNA strand breaks, chromosomal aberrations (Abs), inhibition of DNA synthesis, and mutations. All compounds produced DNA adducts in calf thymus DNA in the presence of rat liver S9. In cultured rat hepatocytes, all produced DNA adducts but none induced DNA strand breaks. In Chinese hamster ovary cells, 3MI and Mel produced DNA adducts, Abs, and inhibition of DNA synthesis with and without S9, except that Mel without S9 did not form adducts. Ser formed DNA adducts, was an equivocal Abs inducer, and suppressed DNA synthesis. Tryp induced neither adducts nor Abs, but did suppress DNA synthesis with S9. Ser and Tryp were less cytotoxic than 3MI and Mel. Mel, Ser, and Tryp failed to induce mutations in Salmonella and E. coli strains with or without S9. 3MI and Mel produced DNA adducts but not mutations in Salmonella TA100 with S9. 3MI and its metabolite indole 3-carbinol also did not induce mutations in a shuttle vector system in human cells. The lack of correlation between DNA adducts and other genotoxicity endpoints for these indole compounds may be due to the higher sensitivity of the (32)P-postlabeling adduct assay or it may indicate that the indole-DNA adducts per se are not mutagenic and are not able to induce strand breaks or alkali-labile lesions. The indole-induced Abs may result from cytotoxicity and suppression of DNA synthesis with minimal if any contribution from DNA adducts.     

Attitudes about genetic risk of couples undergoing in-vitro fertilization

Many couples undergoing in-vitro fertilization (IVF) are at a higher risk of having a child with a genetic abnormality. In a sample of 55 consecutive couples starting IVF, only 33% had no genetic risk factor. The most common genetic risks were advanced maternal age and possible abnormalities associated with severe male infertility. Despite education on these risks, 71% of couples had no interest in receiving formal genetic counselling. Only 14% of couples at risk would consider using a gamete donor to avoid transmitting a genetic disorder to a child. The triple test to screen for fetal abnormalities was acceptable to 82% of couples, but only 47% planned to have amniocentesis or chorionic villi sampling. Couples were significantly more likely to opt for prenatal testing if they would consider terminating a pregnancy should the fetus have a severe genetic abnormality (P < 0.01). Roman Catholic couples tended to have more conservative attitudes about pregnancy termination. Socio-economic status and whether the infertility factor was male or female were not predictors of a couple's attitudes.      

Expert opinion on the management and follow-up of uveitis patients during SARS-CoV-2 outbreak

ABSTRACT

Introduction

Routine medical and ophthalmic care is being drastically curtailed in the context of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic. Uveitis patients require particular attention because of their theoretical risk of viral infection, in the context of therapeutic immunosuppression.     

Tetrasomy 12pter-12p13.31 in a girl with partial Pallister-Killian syndrome phenotype

A dysmorphic patient was shown to carry a small supernumerary marker chromosome. Multicolor, centromere-multicolor and regular FISH experiments proved the marker to be an analphoid 12pter derived isochromosome. Microdissection of the marker followed by reverse painting and array CGH analysis showed that the isochromosome contains approximately 6 Mb of 12pter-12p13.31 derived sequence. This is only the second report of a marker with a neocentromere 12pter and the molecular fine mapping of the duplicated region further refines the 12p region defining the Pallister-Killian syndrome phenotype. In addition, we show the feasibility of using microdissected chromosomes or chromosomal fragments to molecularly map the chromosomal breakpoints on array CGH. This technology may aid in the identification of chromosomal translocation breakpoints.