Design and implementation of a system for treating paediatric patients with stereotactically-guided conformal radiotherapy.

BACKGROUND AND PURPOSE: Stereotactically-guided conformal radiotherapy (SCRT) allows the delivery of highly conformal dose distributions to localised brain tumours. This is of particular importance for children, whose often excellent long-term prognosis should be accompanied by low toxicity. The commercial immobilisation system in use at our hospital for adults was felt to be too heavy for children, and precluded the use of anaesthesia, which is sometimes required for paediatric patients. This paper therefore describes the design and implementation of a system for treating children with SCRT. This system needed to be well tolerated by patients, with good access for treating typical childhood malignancies. MATERIALS AND METHODS: A lightweight frame was developed for immobilisation, with a shell-based alternative for patients requiring general anaesthetic. Procedures were set up to introduce the patients to the frame system in order to maximise patient co-operation and comfort. Film measurements were made to assess the impact of the frame on transmission and surface dose. The reproducibility of the systems was assessed using electronic portal images. RESULTS: Both frame and shell systems are in clinical use. The frame weighs 0.6 kg and is well tolerated. It has a transmission of 92-96%, and fields which pass through it deliver surface doses of 58-82% of the dose at d(max), compared to 18% when no frame is present. However, the frame is constructed to maximise the availability of unobstructed beam directions. Reproducibility measurements for the frame showed a mean random error of 1.0+/-0.2mm in two dimensions (2D) and 1.4+/-0.7 mm in 3D. The mean systematic error in 3D was 2.2mm, and 90% of all overall 3D errors were less than 3.4mm. For the shell system, the mean 2D random error was 1.5+/-0.2mm. CONCLUSIONS: Two well-tolerated immobilisation devices have been developed for fractionated SCRT treatment of paediatric patients. A lightweight frame system gives a wide range of possible unobstructed beam directions, although beams that intersect the frame are not precluded, provided that output corrections are applied. A shell system allows the use of general anaesthesia. Both systems give reproducible immobilisation to complement the high-precision treatment delivery.

Identification of new X-chromosomal genes required for Drosophila oogenesis and novel roles for fs(1)Yb, brainiac and dunce.

We performed a screen for female sterile mutations on the X chromosome of Drosophila melanogaster and identified new loci required for developmental events in oogenesis as well as new alleles of previously described genes. We present mapping and phenotypic characterization data for many of these genes and discuss their significance in understanding fundamental developmental and cell biological processes. Our screen has identified genes that are involved in cell cycle control, intracellular transport, cell migration, maintenance of cell membranes, epithelial monolayer integrity and cell survival or apoptosis. We also describe new roles for the genes dunce (dnc), brainiac (brn) and fs(1)Yb, and we identify new alleles of Sex lethal (Sxl), ovarian tumor (otu), sans filles (snf), fs(1)K10, singed (sn), and defective chorion-1 (dec-1).

A filter for breast imaging on a radiotherapy X-ray simulator.

Simulator radiographs taken as a record of breast radiotherapy planning often show ill defined breast tissue margins because exposure parameters are set to optimize visualization of the chest wall rather than the bulk of the breast. This creates difficulties when using simulator images as reference images in verification by comparing with either portal film or images from an electronic portal imaging device. Our aim was to improve breast images taken at simulation without changing exposure parameters that have been optimized for visualization of the chest wall. This has been achieved via an external filter to be used when taking radiographs with the treatment simulator. The filter is made of stainless steel coated with tin and is shaped to maintain acceptable imaging of the chest wall by covering only the section of field anterior to the chest wall. Radiographs of breast simulations using the filter have been accepted as satisfactory by both clinicians and radiographers. The filter is now in routine clinical use for breast and chest wall treatment simulation.

The delivery of intensity modulated radiotherapy to the breast using multiple static fields.

BACKGROUND AND PURPOSE: To develop a method of using a multileaf collimator (MLC) to deliver intensity modulated radiotherapy (IMRT) for tangential breast fields, using an MLC to deliver a set of multiple static fields (MSFs). MATERIALS AND METHODS: An electronic portal imaging device (EPID) is used to obtain thickness maps of medial and lateral tangential breast fields. From these IMRT deliveries are designed to minimize the volume of breast above 105% of prescribed dose. The deliveries are universally-wedged beams augmented with a set of low dose shaped irradiations. Dosimetric and planning QA of this method has been compared with the standard, wedged treatment and the corresponding treatment using physical compensators. Several options for delivering the MSF treatment are presented. RESULTS: The MSF technique was found to be superior to the standard technique (P value=0.002) and comparable with the compensated technique. Both IMRT methods reduced the volume of breast above 105% dose from a mean value of 12.0% of the total breast volume to approximately 2.8% of the total breast volume. CONCLUSIONS: This MSF method may be used to reduce the high dose volume in tangential breast irradiation significantly. This may have consequences for long-term side effects, particularly cosmesis.

Loss of hilar mossy cells in Ammon's horn sclerosis.

PURPOSE: Hilar mossy cells represent an important excitatory subpopulation of the hippocampal formation. Several studies have identified this cell type as particularly vulnerable to seizure activity in rat models of limbic epilepsy. Here we have subjected hilar mossy cell loss in the hippocampus of patients with chronic temporal lobe epilepsy (TLE) to a systematic morphological and immunohistochemical analysis. METHODS: Hippocampal specimens from 30 TLE patients were included; 21 patients presented with segmental neuronal cell loss [Ammon's horns clerosis (AHS)] and 8 with focal lesions (tumors, scars, malformations) not involving the hippocampus proper. In one additional TLE patient, no histopathological alteration could be observed. Surgical specimens from tumor patients without epilepsy (n = 2) and nonepileptic autopsy brains (n = 8) were used as controls. Hilar mossy cells in the human hippocampus were visualized using a novel polycloncal antiserum directed against the metabotropic glutamate receptor subtype mGluR7b or by intracellular Lucifer Yellow injection, confocal laser scanning microscopy, and three-dimensional morphological reconstruction. RESULTS: Compared with controls, a significant loss of mGluR7 immunoreactive mossy cells was observed in patients with AHS (p < 0.05). In contrast, TLE patients with focal lesions but structurally intact hippocampus demonstrated only a discrete, nonsignificant reduction of this neuronal subpopulation. This observation was confirmed by analysis of 62 randomly injected hilar neurons from AHS patients, in which we were unable to detect neurons with a morphology like that of hilar mossy cells. CONCLUSION: Our present data indicate significant hilar mossy cell loss in TLE patients with AHS. In contrast, hilar mossy cells appear to be less vulnerable in patients with lesion-associated TLE. Although the significance of mGluR7 immunoreactivity in mossy cells remains to be studied, loss of this cell population is compatible with alterations in hippocampal networks and regional hyperexcitability as pathogenic mechanism of AHS and TLE.

Drosophila Lissencephaly-1 functions with Bic-D and dynein in oocyte determination and nuclear positioning.

Here we show that the Drosophila homologue of Lissencephaly-1, DLis-1, acts together with Bicaudal-D (Bic-D), Egalitarian (Egl), dynein and microtubules to determine oocyte identity. DLis-1 is further required for nurse-cell-to-oocyte transport during oocyte growth, and for the positioning of the nucleus in the oocyte. Immunostaining of DLis-1 protein reveals a cortical localization that is independent of microtubules. DLis-1 may function in this position as a cortical anchor for the other nuclear-localization factors. DLis-1 and Bic-D are further required for nuclear localization in the developing nervous system, indicating that homologues of Bic-D, dynein and Egl-like proteins may also be involved in vertebrate neural migration and that their absence may cause a Miller-Dieker-like lissencephaly.

Cellular pathology of hilar neurons in Ammon's horn sclerosis.

In addition to functionally affected neuronal signaling pathways, altered axonal, dendritic, and synaptic morphology may contribute to hippocampal hyperexcitability in chronic mesial temporal lobe epilepsies (MTLE). The sclerotic hippocampus in Ammon's horn sclerosis (AHS)-associated MTLE, which shows segmental neuronal cell loss, axonal reorganization, and astrogliosis, would appear particularly susceptible to such changes. To characterize the cellular hippocampal pathology in MTLE, we have analyzed hilar neurons in surgical hippocampus specimens from patients with MTLE. Anatomically well-preserved hippocampal specimens from patients with AHS (n = 44) and from patients with focal temporal lesions (non-AHS; n = 20) were studied using confocal laser scanning microscopy (CFLSM) and electron microscopy (EM). Hippocampal samples from three tumor patients without chronic epilepsies and autopsy samples were used as controls. Using intracellular Lucifer Yellow injection and CFLSM, spiny pyramidal, multipolar, and mossy cells as well as non-spiny multipolar neurons have been identified as major hilar cell types in controls and lesion-associated MTLE specimens. In contrast, none of the hilar neurons from AHS specimens displayed a morphology reminiscent of mossy cells. In AHS, a major portion of the pyramidal and multipolar neurons showed extensive dendritic ramification and periodic nodular swellings of dendritic shafts. EM analysis confirmed the altered cellular morphology, with an accumulation of cytoskeletal filaments and increased numbers of mitochondria as the most prominent findings. To characterize cytoskeletal alterations in hilar neurons further, immunohistochemical reactions for neurofilament proteins (NFP), microtubule-associated proteins, and tau were performed. This analysis specifically identified large and atypical hilar neurons with an accumulation of low weight NFP. Our data demonstrate striking structural alterations in hilar neurons of patients with AHS compared with controls and non-sclerotic MTLE specimens. Such changes may develop during cellular reorganization in the epileptogenic hippocampus and are likely to contribute to the pathogenesis or maintenance of temporal lobe epilepsy.

vasa is required for GURKEN accumulation in the oocyte, and is involved in oocyte differentiation and germline cyst development.

The Drosophila gene vasa is required for pole plasm assembly and function, and also for completion of oogenesis. To investigate the role of vasa in oocyte development, we generated a new null mutation of vasa, which deletes the entire coding region. Analysis of vasa-null ovaries revealed that the gene is involved in the growth of germline cysts. In vasa-null ovaries, germaria are atrophied, and contain far fewer developing cysts than do wild-type germaria; a phenotype similar to, but less severe than, that of a null nanos allele. The null mutant also revealed roles for vasa in oocyte differentiation, anterior-posterior egg chamber patterning, and dorsal-ventral follicle patterning, in addition to its better-characterized functions in posterior embryonic patterning and pole cell specification. The anterior-posterior and dorsal-ventral patterning phenotypes resemble those observed in gurken mutants. vasa-null oocytes fail to efficiently accumulate many localized RNAs, such as Bicaudal-D, orb, oskar, and nanos, but still accumulate gurken RNA. However, GRK accumulation in the oocyte is severely reduced in the absence of vasa function, suggesting a function for VASA in activating gurken translation in wild-type ovaries.

Practical implementation of compensators in breast radiotherapy.

BACKGROUND AND PURPOSE: A method of using electronic portal imaging to design compensators for tangential breast irradiation has been developed. We describe how this has been implemented. MATERIALS AND METHODS: The compensator design method generates wedged and unwedged beam weights, in conjunction with templates for multiple lead-sheet compensators and pseudo-CT outlines. The latter describe the breast and lung profiles in a set of transverse slices. The layers of the compensator and pseudo-CT outlines are transferred to a treatment planning system for verification. The accuracy of the planning system for the high transmission blocks used to describe the compensators has been verified using a plotting tank system. Dose volume histogram data and transaxial and sagittal plan slices have been compared for both standard and compensated treatments for a sample set of five patients. RESULTS: The planning system predicted the dose at depths of 1.5 and 5 cm to within 2% for the compensators tested. The biggest source of discrepancy was a consequence of the planning system requiring blocks to have integer percentage transmission. For all patients studied, the compensated treatment resulted in a significant reduction in the percentage volume outside the 95-105% dose, with an average reduction of 10.2%. The percentage volume outside the 95-107% dose was also reduced by typically 3.4%. The implementation was found to yield a convenient automatic method of designing compensators using electronic portal imaging and verifying the results using a planning system. CONCLUSIONS: These results indicate that this method of implementation can be used in practice. The dosimetric accuracy of the treatment planning system is limited by the requirement that blocks should be of integer transmission, but this effect is small.

[Portal vein and hepatic vein thrombosis in occult myeloproliferative syndrome. Progression of thrombosis under heparin therapy]. / Pfortader- und Lebervenen-verschlüsse bei okkultem myeloproliferativem Syndrom. Thromboseprogression unter Heparin.

In a 45-year-old woman presenting with subacute liver failure and portal hypertension the diagnostic workup revealed portal vein thrombosis and occlusion of small hepatic veins. An occult myeloproliferative syndrome was assumed. During full-dose heparin therapy the thrombotic process progressed to segmental venous small bowel infarctions, liver failure and death. In-vitro culture of mononuclear blood cells showed spontaneous growth of erythroid precursor cells. Necropsy demonstrated acute hemorrhagic necrosis of the liver, thrombotic material within the portal and mesenteric veins, thrombosis, dilatation, sclerosis, and partial obliteration of small portal vein branches, and obliterative fibrosis and thrombosis of small intrahepatic veins. The bone marrow and spleen findings support the diagnosis of a myeloproliferative disorder.

The Drosophila melanogaster homolog of the mammalian MAPK-activated protein kinase-2 (MAPKAPK-2) lacks a proline-rich N-terminus.

Recently, a mammalian kinase cascade was discovered that is triggered by stress and heat shock, and leads to the stimulation of mitogen-activated protein kinase (MAPK)-activated protein kinase-2 (MAPKAPK-2). Surprisingly, this process turns out to be independent of the classical MAPK. The stress-induced activation of MAPKAPK-2, in turn, results in the phosphorylation of small heat-shock proteins (Hsp). We have isolated a Drosophila melanogaster (Dm) cDNA encoding a polypeptide that has extensive sequence similarity to the mammalian MAPKAPK-2. As in mammalian MAPKAPK-2, the Dm MAPKAPK-2 possesses a MAPK phosphorylation site and a nuclear targeting sequence located C-terminal to the catalytic domain. However, in contrast to its mammalian counterpart, it lacks the Pro-rich N-terminal region proposed to form Src-homology domain 3 (SH3) binding domains. A 2.4-kb MAPKAPK-2 message is expressed throughout development, while two shorter transcripts of 2.3 and 1.8 kb appear to be specifically expressed in the germline. The 1.8-kb transcript results from the usage of an atypical germline-specific polyadenylation signal (AATATA) located early within the 3' untranslated region. Dm MAPKAPK-2 is located at cytological position 5D in the Dm genome.

Cloning of the cDNA encoding the porcine p55 tumor necrosis factor receptor.

We have utilized RT-PCR to clone the porcine p55TNFR cDNA, encoding the 55-kDa tumor necrosis factor receptor (TNFR), encompassing the entire coding region and most of the 3' untranslated region. PCR was performed using total cellular RNA of porcine kidney cell line 15 [PK(15)] and primers for the human p55TNFR. Since the length of the entire fragment was over 2000 bp, we fused two amplified subfragments with the help of a restriction endonuclease. The entire fragment was cloned and its amino acid (aa) sequence was compared to the human, rat and mouse p55TNFR. This comparison revealed identities of 79, 71 and 72%, respectively. The highest identities of 90, 80 and 85% were detected in the so called "death domain" for the human, rat and mouse sequences, respectively. This domain is crucial for the cytotoxic signal transduction of p55TNFR.

Null alleles reveal novel requirements for Bic-D during Drosophila oogenesis and zygotic development.

In the Drosophila ovary, the Bicaudal-D (Bic-D) gene is required for the differentiation of one of 16 interconnected cystocyte sister cells into an oocyte. A new class of Bic-Dnull alleles reveals a novel requirement for Bic-D for zygotic viability. In the germ line, the null mutations show that developmental processes that take place in germarial region 1, even those that create asymmetry, are independent of Bic-D function. Bic-D is then required to establish oocyte identity in one cystocyte and is essential, not only for the oocyte-specific accumulation of all oocyte markers that we have tested so far, but also for the posterior migration of the oocyte. In addition, normal polarity amongst the nurse cells requires Bic-D, indicating that the creation of different nurse cell identities may depend on oocyte determination. Our results show that different processes in early oogenesis require different amounts of Bic-D in a process-specific way and certain later processes can proceed at low levels of Bic-D. This suggests that the patterning of the female germ line and the development of an oocyte depend on differential responses to a single activity that is capable of initiating distinct oogenesis processes and can establish different cell fates.

Requirement for phosphorylation and localization of the Bicaudal-D protein in Drosophila oocyte differentiation.

In the Drosophila female the product of the germline stem cell, the cystoblast, gives rise to 16 interconnected cystocytes. One of them differentiates into the oocyte, while the 15 others become polyploid nurse cells. Bic-D is required for the differentiation of an oocyte and hence for fertility. Recessive mutations in Bic-D block the oocyte-specific accumulation of its own and other RNAs. Based on its properties and distribution, the Bic-D protein appears to be a component of a cytoskeletal transport or anchoring system. Additional results suggest that the phosphorylation of the Bic-D protein is essential for its accumulation in the pro-oocyte and that this process leads to the gradual localization to the pro-oocyte of factors required for oocyte differentiation.

Bicaudal-D, a Drosophila gene involved in developmental asymmetry: localized transcript accumulation in ovaries and sequence similarity to myosin heavy chain tail domains.

The Bicaudal-D (Bic-D) gene is essential for the differentiation of the oocyte in Drosophila. Dominant gain-of-function mutations result in the formation of double abdomen embryos. The Bic-D gene was cloned and identified using restriction fragment length polymorphisms, Northern analysis, and transformation rescue. Bic-D RNA accumulates in the oocyte during the earliest stages of oogenesis and is localized anteriorly in later stages. The predicted protein contains several extended amphipathic helices, and its similarity to myosin heavy chain tails, paramyosin, and kinesin suggests a similar type of coiled-coil protein interaction.

[Is the aorto-coronary bypass operation useful in patients with advanced coronary sclerosis and poor ventricular function?]. / Bringt die aorto-koronare Bypass-Operation einen Nutzen bei Patienten mit fortgeschrittener Koronarsklerose und schlechter Ventrikelfunktion?

The prognosis and long term results in 56 patients with coronary artery disease and impaired left ventricular function (EF less than or equal to 40%) who underwent aortocoronary bypass surgery (all cases) and aneurysmectomy (26 cases) between 1972 and 1980 were compared with those in 47 equally ill patients treated medically. Survival was significantly higher in the surgical than in the non-surgical group, the survival rate being 80% and 58% respectively at 41 months after study entry (p = 0.012). No difference in survival was observed between grafted patients and patients in whom additional aneurysmectomy was performed. 26 patients were recatheterized postoperatively and this revealed an increase in left ventricular ejection fraction at rest from 33 +/- 5% to 44 +/- 11% (p less than 0.001) and a decrease in left ventricular end-diastolic pressure from 18 +/- 8 mm Hg to 14 +/- 8 mm Hg (p less than 0.025). Postoperatively the patients had less angina and physical working capacity increased. At restudy the average NYHA class had decreased in the surgical group from 2.9 +/- 0.7 to 2.1 +/- 0.9 (p less than 0.001) but was unchanged in the non-surgical group (2.6 +/- 0.6 and 2.6 +/- 0.7 respectively). It is concluded that aortocoronary bypass surgery improves survival, left ventricular function and symptoms in patients with coronary artery disease and severely impaired myocardial function.