Mutations affecting the formation and function of the cardiovascular system in the zebrafish embryo

As part of a large-scale mutagenesis screen of the zebrafish genome, we have identified 58 mutations that affect the formation and function of the cardiovascular system. The cardiovascular system is particularly amenable for screening in the transparent zebrafish embryo because the heart and blood vessels are prominent and their function easily examined. We have classified the mutations affecting the heart into those that affect primarily either morphogenesis or function. Nine mutations clearly disrupt the formation of the heart. cloche deletes the endocardium. In cloche mutants, the myocardial layer forms in the absence of the endocardium but is dysmorphic and exhibits a weak contractility. Two loci, miles apart and bonnie and clyde, play a critical role in the fusion of the bilateral tubular primordia. Three mutations lead to an abnormally large heart and one to the formation of a diminutive, dysmorphic heart. We have found no mutation that deletes the myocardial cells altogether, but one, pandora, appears to eliminate the ventricle selectively. Seven mutations interfere with vascular integrity, as indicated by hemorrhage at particular sites. In terms of cardiac function, one large group exhibits a weak beat. In this group, five loci affect both chambers and seven a specific chamber (the atrium or ventricle). For example, the weak atrium mutation exhibits an atrium that becomes silent but has a normally beating ventricle. Seven mutations affect the rhythm of the heart causing, for example, a slow rate, a fibrillating pattern or an apparent block to conduction. In several other mutants, regurgitation of blood flow from ventricle to atrium is the most prominent abnormality, due either to the absence of valves or to poor coordination between the chambers with regard to the timing of contraction. The mutations identified in this screen point to discrete and critical steps in the formation and function of the heart and vasculature.

Mutations affecting development of the zebrafish ear

In a large scale screen for genetic defects in zebrafish embryogenesis we identified mutations affecting several aspects of ear development, including: specification of the otic placode, growth of the otic vesicle (otocyst), otolith formation, morphogenesis of the semicircular canals and differentiation of the otic capsule. Here we report initial phenotypic and genetic characterization of 20 of these mutations defining 13 independent loci. Embryos mutant at the quadro locus display abnormal specification of the otic placode. As revealed by dlx-3 expression, the otic field in the mutant embryos is smaller or split into two fields. At later stages of development the ear of quadro mutants is frequently divided into two smaller, incomplete units. Four loci affect ear shape shortly after formation of the otic vesicle. All of them also display abnormal brain morphology. Mutations in five loci result in the absence of otolith formation; two of these also produce changes of ear morphology. Two loci, little richard and golas, affect morphology of the otic vesicle shortly before formation of the semicircular canals. In both cases the morphogenesis of the semicircular canals is disrupted. Finally, the antytalent locus is involved in late expansion of the ear structure. Analysis of mutations presented here will strengthen our understanding of vertebrate ear morphogenesis and provide novel entry points to its genetic analysis.

[Intracavitary brachytherapy method using after-loading for treatment of women with endometrial uterine neoplasm]

We would like to introduce intracavitary brachytherapy using double rod-shaped applicators. The women who are treated with this method are evaluated in III FIGO stage and the patients in stage I and II who could not undergo the operation. This method allows to distribute equally the dose in whole uterus, insertion of the applicators is not difficult. The brachytherapy treatment is well tolerated.

[Combined dose distribution in the small pelvis of postsurgical radiotherapy patients with cancer of the endometrium]

X-ray's doses in the pelvis area was published and discussed in this paper. On the CT scan base, doses was calculated by the treatment planning system Target 2 plus. The analysis of dose distribution was performed on 26 patients with the postsurgical cancer of endometrium. The treatment was combined teletherapy and brachytherapy techniques.

Can busulfan replace fractionated total body irradiation as conditioning regimen for allogeneic bone marrow transplantation in children with acute lymphoblastic leukemia

The results of allogenic bone marrow transplantation (allo-BMT) in 26 children with ALL treated with the same initial- and relapse-BFM-protocols, but transplanted in different centers (Poznań, Wroclaw, Hannover) after conditioning with two different regimens have been compared. Ten children (6 in Poznań, 4 in Wroclaw) were conditioned for BMT with busulfan and cyclophosphamide when fractionated TBI (FTBI) was not available there. Sixteen children obtained FTBI and etoposide (11 in Hannover, where in children with ALL exclusively chemoradioconditioning regimen has been employed, and 5 in Poznań). It has been found, that the chemoconditioning procedure was probably less effective (5-year EFS 18%) than the regimen with FTBI (7-year EFS 60%). Therefore, TBI seems to be at this point still mandatory in pediatric ALL patients, unless combinations of chemotherapeutic drugs might be able to substitute the radiation in the future.

[Combined calculation of dosage for brachytherapy and external beam therapy in radiation treatment of cervix cancer]

In this paper authors present complex doses of ionizing radiation from brachytherapy and external beam therapy. Doses were determined on Computerized Planning System--Target 2 plus for patients with cancer of cervix.

A method for improving the output dose rate protocols for cobalt machines

A method of correcting the output dose rate of the radiotherapeutic cobald units is presented. This method links measurements values with the decay formula for increasing the accuracy of output dose rate determining. The least squares method has been applied to mathematical processing of the data. Results were discussed on the record of output dose rate which had been measured since 1969.

Functional analysis of the mouse homeobox gene HoxB9 in Drosophila development

Mammalian genomes contain clusters of homeobox genes (Hox-C, HOX-C) which are structurally similar to the homeotic genes of the Drosophila HOM complex. One method for assessing the functional similarity of particular Drosophila HOM and mammalian Hox genes is to test the ability of Hox genes to induce homeotic phenotypes when expressed in developing Drosophila. Here we describe such functional tests using mouse HoxB9 (formerly Hox-2.5), whose closest structural relative in Drosophila is Abdominal-B. When expressed from a heat shock promoter, HoxB9 induces transformations of head towards more posterior identities in Drosophila larvae and adults. These transformations share some similarities with the phenotypic effects produced by ectopically expressed Abdominal-B, but are also similar to the transformations induced by Antennapedia and mouse HoxB6 (Hox-2.2), suggesting that HoxB9 specifies a positional identity that is intermediate between Antennapedia and Abdominal-B.

[Influence of applicator moves to dose distribution during Selectron LDR brachytherapy]

Irradiation of cancer diseases with intracavitary applicator makes impossible visual control of applicator's position during the process of irradiation. In this paper example applicator moves during the treatment are presented and their influence to dose distribution especially in reference points is discussed. Verification of applicator's position has been made by the use of roentgen films.

A human HOX4B regulatory element provides head-specific expression in Drosophila embryos

Like other homeobox genes of the Antennapedia and bithorax complexes (collectively called the HOM complex), the Drosophila Deformed (Dfd) gene has structural homologues in the Hox/HOX complexes of mouse and humans, one of which is human HOX4B (refs 3, 4). Previous experiments indicated that HOX4B protein can specifically activate the expression of the endogenous Dfd transcription unit in Drosophila embryos and larvae. We therefore asked whether HOX4B cis-regulatory elements could mimic the function of a Dfd autoregulatory element in Drosophila embryos. Here we show that a HOX4B upstream element can surprisingly provide expression in a posterior head segment of Drosophila. One possible mechanism for the axial position-specificity of the human element may involve the conservation of a Dfd-specific autoregulatory circuit in both arthropod and chordate lineages. This possibility is supported by the finding that a Drosophila Dfd autoregulatory element supplies spatially localized expression in the hindbrain of mouse embryos.

Dose rate in irregularly shaped high energy photon beams

A quick method of calculating the dose-rate distribution in irregularly shaped beams is presented. This method is partly based on the Cunningham model. The proposed modifications make it possible to avoid the scatter functions in favor of direct use of tissue-phantom ratios and field size coefficients. The problem has been evaluated for photons generated by 10 and 23 MV linacs. The calculated dose rates have been compared with measured ones, and good accuracy has been achieved.

Dose-rate distribution under partially shielded beams

We are presenting a method of calculating the dose-rate distributions in partially shielded field. An attenuator was placed in central beam axis and also in an off-axis geometry. The study was made with a Co-60 radiation and with photons generated by 10 and 23 MV Linac at depths, in phantom, from 5 to 30 cm. To obtain the calculated values of dose-rates; the contributions of the three components to the total dose-rate were measured. The calculated dose-rate distributions agree well with the measured data in case of 10 MV and 23 MV radiation.

Genetic evidence that acute morphologic transformation, induction of cellular DNA synthesis, and focus formation are mediated by a single activity of the bovine papillomavirus E5 protein

The bovine papillomavirus (BPV) type 1 E5 gene encodes a 44-amino-acid protein that can stably transform cultured rodent cells when expressed in the absence of all other viral genes. We have previously constructed a BPV-simian virus 40 recombinant virus (Pava-1) which efficiently expresses the BPV type 1 E5 gene in infected cells (J. Settleman and D. DiMaio, Proc. Natl. Acad. Sci. USA 85:9007-9011, 1988). Within 48 h of Pava-1 infection, the vast majority of mouse C127 cells underwent a dramatic morphologic transformation which was accompanied by cell proliferation. Infection of C127 cells made quiescent by contact inhibition and serum starvation caused a great induction of cellular DNA synthesis. These morphologic and mitogenic responses were proportional to the virus multiplicity of infection. Mutational analysis indicated that the E5 gene is both necessary and sufficient for these activities. Analysis of a variety of E5 missense mutants revealed a strong correlation between their phenotypes in the acute transformation assays following infection and in the stable focus-forming assay following transfection. Most of the defective mutants expressed normal levels of E5 protein following infection, indicating that their defective phenotypes are not due to the synthesis of an unstable protein. The failure to genetically resolve these E5 activities suggests that the ability of the E5 protein to cause acute morphologic transformation and reentry into the cell cycle may be intimately related to its ability to cause stable cell transformation and that these functions are probably mediated by a single biochemical activity of the E5 protein.