The swollen leg and primary lymphoedema

Children who present with unilateral or bilateral swelling of the legs are often suspected of having a deep venous thrombosis. The incidence of deep venous thrombosis in children is low and lymphoedema may be a more appropriate diagnosis. Lymphoedema can be primary or secondary. In childhood, primary lymphoedema is more common and may be seen associated with other congenital abnormalities, such as cardiac anomalies or gonadal dysgenesis. Primary hypoplastic lymphoedema is the most often encountered type. It is more common in girls, especially around puberty, and is typically painless. Atypical presentations produce diagnostic confusion and may require imaging to confirm the presence, extent, and precise anatomical nature of the lymphatic dysplasia. This article describes four patients presenting with limb pain and reviews the clinical features and imaging options in children with suspected lymphoedema.     

Tyrosine kinase inhibitors. 17. Irreversible inhibitors of the epidermal growth factor receptor: 4-(phenylamino)quinazoline- and 4-(phenylamino)pyrido[3,2-d]pyrimidine-6-acrylamides bearing additional solubilizing functions

4-Anilinoquinazoline- and 4-anilinopyrido[3,2-d]pyrimidine-6-acrylamides substituted with solubilizing 7-alkylamine or 7-alkoxyamine side chains were prepared by reaction of the corresponding 6-amines with acrylic acid or acrylic acid anhydrides. In the pyrido[3,2-d]pyrimidine series, the intermediate 6-amino-7-alkylamines were prepared from 7-bromo-6-fluoropyrido[3,2-d]pyrimidine via Stille coupling with the appropriate stannane under palladium(0) catalysis. This proved a versatile method for the introduction of cationic solubilizing side chains. The compounds were evaluated for their inhibition of phosphorylation of the isolated EGFR enzyme and for inhibition of EGF-stimulated autophosphorylation of EGFR in A431 cells and of heregulin-stimulated autophosphorylation of erbB2 in MDA-MB 453 cells. Quinazoline analogues with 7-alkoxyamine solubilizing groups were potent irreversible inhibitors of the isolated EGFR enzyme, with IC(50[app]) values from 2 to 4 nM, and potently inhibited both EGFR and erbB2 autophosphorylation in cells. 7-Alkylamino- and 7-alkoxyaminopyrido[3,2-d]pyrimidines were also irreversible inhibitors with equal or superior potency against the isolated enzyme but were less effective in the cellular autophosphorylation assays. Both quinazoline- and pyrido[3,2-d]pyrimidine-6-acrylamides bound at the ATP site alkylating cysteine 773, as shown by electrospray ionization mass spectrometry, and had similar rates of absorptive and secretory transport in Caco-2 cells. A comparison of two 7-propoxymorpholide analogues showed that the pyrido[3,2-d]pyrimidine-6-acrylamide had greater amide instability and higher acrylamide reactivity, being converted to glutathione adducts in cells more rapidly than the corresponding quinazoline. This difference may contribute to the observed lower cellular potency of the pyrido[3,2-d]pyrimidine-6-acrylamides. Selected compounds showed high in vivo activity against A431 xenografts on oral dosing, with the quinazolines being superior to the pyrido[3,2-d]pyrimidines. Overall, the quinazolines proved superior to previous analogues in terms of aqueous solubility, potency, and in vivo antitumor activity, and one example (CI 1033) has been selected for clinical evaluation.     

Reovirus prolongs survival and reduces the frequency of spinal and leptomeningeal metastases from medulloblastoma

Medulloblastoma (MB), the most common pediatric brain tumor, is a highly malignant disease with a 5-year survival rate of only 60%. Tumor cells invade surrounding tissue and disseminate through cerebral spinal fluid, making treatment difficult. Human reovirus type 3 exploits an activated Ras pathway in tumor cells to support productive infection as an oncolytic virus. Here, we examined the ability of human reovirus to kill MB cells lines and surgical specimens in vitro and inhibit tumor growth/metastases in vivo. Most human MB cell lines tested (five of seven = 71.4%), two MB cell lines derived from spontaneously arising tumors in Patched-1(+/-) mice (two of two = 100%) and three MB primary cultures derived from surgical specimens, were susceptible to reovirus infection. Reovirus was internalized and transcribed in both susceptible and resistant cell lines. However, viral protein synthesis was restricted to cell lines with higher levels of activated Ras, suggesting that Ras plays a critical role in reovirus oncolysis in MB. Using an in vivo Daoy orthotopic animal model, we found that a single i.t. injection of reovirus dramatically prolonged survival compared with controls (160 versus 70 days, respectively; P = 0.0003). Repeating this experiment with GFP-labeled Daoy cells and multiple i.t. administrations of reovirus, we again found prolonged survival and a dramatic reduction in spinal and leptomeningeal metastases (66.7% in control injections versus 0.0% in the live virus group). These data suggest that this oncolytic virus may be a potentially effective novel therapy against human MB. Its ability to reduce metastases to the spinal cord could allow a reduction in the dose/field of total neuroaxis cerebral-spinal radiotherapy currently used to treat/prevent cerebral spinal fluid dissemination.     

Suppression of high-density artefacts in x-ray CT images using temporal digital subtraction with application to cryotherapy

Image guidance in cryotherapy is usually performed using ultrasound. Although not currently in routine clinical use, x-ray CT imaging is an alternative means of guidance that can display the full 3D structure of the iceball, including frozen and unfrozen regions. However, the quality of x-ray CT images is compromised by the presence of high-density streak artefacts. To suppress these artefacts we applied temporal digital subtraction (TDS). This TDS method has the added advantage of improving the grey scale contrast between frozen and unfrozen tissue in the CT images. Two sets of CT images were taken of a phantom material, cryoprobes and a urethral warmer (UW) before and during the cryoprobe freeze cycle. The high density artefacts persisted in both image sets. TDS was performed on these two image sets using the corresponding mask image of unfrozen material and the same geometrical configuration of the cryoprobes and the UW. The resultant difference image had a significantly reduced artefact content. Thus TDS can be used to significantly suppress or eliminate high-density CT streak artefacts without reducing the metallic content of the cryoprobes. In vivo study needs to be conducted to establish the utility of this TDS procedure for CT assisted prostate or liver cryotherapy. Applying TDS in x-ray CT guided cryotherapy will facilitate estimation of the number and location of all frozen and unfrozen regions, potentially making cryotherapy safer and less operator dependent.     

Cytoplasmic RNA in nervous system tumours in children: a fluorochromic histochemical study using acridine orange

Acridine orange was used as a fluorochromic histochemical stain of nucleic acids, applied to 78 neoplasms of the central and peripheral nervous systems of 60 children. Some cases were compared with 5 adults and 4 other cases of chronic reactive gemistocytic gliosis. Opposite concentration gradients of cytoplasmic ribonucleic acid (RNA) was demonstrated in tumours of the neuronal/neuroectodermal series, and those of the glial/neuroepithelial series. Minimal AO-RNA fluorescence was seen in 8 cerebellar medulloblastomas and in a retinoblastoma; strong AO-RNA fluorescence occurred in one cerebellar medulloblastoma and in 3 primitive neuroectodemal tumours of the cerebral cortex. Intermediate intensity of fluorescence was found in neuroblastomas, and strong fluorescence was shown in well differentiated ganglioneuroma cells and in cells of chromaffin tumours. Among glial tumours, by contrast, the most anaplastic cells displayed the most RNA fluorescence, while better differentiated astrocytoma cells showed much less. Gradients also were found within some astrocytomas, corresponding to zones of relative anaplasia. Minimal or no fluorescence was detected in reactive gemistocytes or in oligodendroglioma cells. Ependymomas were weakly fluorescent and choroid plexus papillomas showed more fluorescence, similar to the findings in normal ependyma and choroid plexus. Several non-neuroepithelial tumours of the nervous system and Schwannomas also were studied. The acridine orange technique applied to either frozen or paraffin sections of nervous system tumours, has value as an adjunct in the diagnosis and grading of these neoplasms and perhaps in distinguishing reactive gliosis from benign astrocytoma.     

A semi-empirical treatment planning model for optimization of multiprobe cryosurgery

A model is presented for treatment planning of multiprobe cryosurgery. In this model a thermal simulation algorithm is used to generate temperature distribution from cryoprobes, visualize isotherms in the anatomical region of interest (ROI) and provide tools to assist estimation of the amount of freezing damage to the target and surrounding normal structures. Calculations may be performed for any given freezing time for the selected set of operation parameters. The thermal simulation is based on solving the transient heat conduction equation using finite element methods for a multiprobe geometry. As an example, a semi-empirical optimization of 2D placement of six cryoprobes and their thermal protocol for the first freeze cycle is presented. The effectiveness of the optimized treatment protocol was estimated by generating temperature-volume histograms and calculating the objective function for the anatomy of interest. Two phantom experiments were performed to verify isotherm locations predicted by calculations. A comparison of the predicted 0 degrees C isotherm with the actual iceball boundary imaged by x-ray CT demonstrated a spatial agreement within +/-2 mm.     

Pituitary adenomas associated with elevated blood follicle-stimulating hormone levels: a histologic, immunocytologic, and electron microscopic study of two cases

The histologic, immunocytologic, and electron microscopic features of pituitary adenomas surgically removed from two men with elevated levels of blood follicle-stimulating hormone (FSH) are described. In both cases, the high blood FSH levels were reduced after surgery. By light microscopy, the tumors corresponded to chromophobic adenomas, and the immunoperoxidase technique revealed the presence of immunoreactive FSH (beta-subunit) in the cytoplasm of the adenoma cells. By electron microscopy, the adenoma cells differed considerably from nontumorous FSH cells. They were smaller and angular and contained numerous microtubules as well as spherical secretory granules measuring 100 to 250 nm in diameter and often lining up along the cell membranes. The present findings are consistent with the view that FSH-producing adenomas may originate in the human pituitary.