Gastrin-releasing peptide-induced down-regulation of tumor suppressor protein PTEN (phosphatase and tensin homolog deleted on chromosome ten) in neuroblastomas

OBJECTIVES: To evaluate whether aggressive, undifferentiated neuroblastomas express tumor suppressor protein PTEN (phosphatase and tensin homolog deleted on chromosome ten) and to examine the effects of gastrin-releasing peptide (GRP) on PTEN gene and protein expression. SUMMARY BACKGROUND DATA: We have previously shown that neuroblastomas secrete GRP, which binds to its cell surface receptor (GRP-R) to stimulate cell growth in an autocrine fashion. However, the effects of GRP on expression of the tumor suppressor gene PTEN have not been elucidated in neuroblastomas. METHODS: Paraffin-embedded sections from human neuroblastomas were analyzed for PTEN and phospho-Akt protein expression by immunohistochemistry. Human neuroblastoma cell lines (SK-N-SH and SH-SY5Y) were stably transfected with the plasmid pEGFP-GRP-R to establish GRP-R overexpression cell lines, and the effects of GRP on PTEN gene and protein expression were determined. RESULTS: A decrease in the ratio of PTEN to phospho-Akt protein expression was identified in poorly differentiated neuroblastomas. An increase in GRP binding capacity was confirmed in GRP-R overexpressing cells, which demonstrated an accelerated constitutive cell growth rate. PTEN gene and protein expression was significantly decreased in GRP-R overexpressing cells when compared with controls. CONCLUSIONS: Our findings demonstrate decreased expression of the tumor suppressor protein PTEN in more aggressive undifferentiated neuroblastomas. An increase in GRP binding capacity, as a result of GRP-R overexpression, down-regulates PTEN expression. These findings suggest that an inhibition of the tumor suppressor gene PTEN may be an important regulatory mechanism involved in GRP-induced cell proliferation in neuroblastomas.     

Neonatal airway obstruction caused by rapidly growing nasopharyngeal teratoma

A case report is presented of a rapidly growing congenital nasopharyngeal teratoma (epignathus) in a preterm infant, leading to severe upper airway obstruction. Prenatal diagnosis by ultrasonography did not reveal the condition because the tumour masses were initially small and there was no polyhydramnios. Epignathus is a rare cause of upper airway obstruction of the newborn that can grow rapidly in the neonatal period and should be treated surgically.
Conclusion:  Epignathus is a rare cause of upper airway obstruction of the newborn that can grow rapidly in the neonatal period.     

头孢克肟胶囊人体药动学研究及生物等效性评价

目的：研究头孢克肟胶囊在健康人体内的药动学及生物等效性。方法：以18名健康志愿者为试验对象，采用同体交叉试验方法，分别单剂量口服受试制剂或参比制剂各400mg，采用HPLC法测定血浆中药物浓度。结果：参比制剂和受试制剂的tmax分别为（3．39±0．50）和（3．39±0．50）h，cmax分别为（2．33±0．33）和（2．27±0．25）μg／mL，t1／2分别为（3．92±0．85）和（4．41±0．68）h，AUC0～16分别为（14．61±2．67）和（14．82±2．02）μg·h·mL^-1，AUC0～∞分别为（16．00±3．13）和（16．81±2．62）μg·h·mL^-1。结论：受试制剂与参比制剂生物等效，受试制剂的相对生物利用度为（98．69±13．13）％。     

Cell cycle and melanoma--two different tumours from the same cell type

Melanoma of the uvea of the eye and melanoma of the skin share a common cell of origin, but differ substantially in their behaviour and response to chemotherapy. There is increasing evidence that this is related to differences in their molecular phenotype, particularly in relation to the expression of cell cycle-associated proteins. Since many cytotoxic agents act by damaging DNA, resistance is often associated with intact mechanisms which allow the neoplastic cells to arrest their growth while DNA is repaired, or to resist apoptosis in response to detection of DNA damage. p53 is important to these processes, but mutation appears to be a less common event in uveal melanoma than in skin melanoma, probably due to the lack of UV exposure in the uvea. There are also differences in proliferation-associated proteins such as c-myc and cyclin D1. Overexpression of the former molecule is associated with a poor prognosis in skin melanoma, but is associated with a good prognosis in uveal melanoma, although there is considerable genetic heterogeneity within each type. While prognostic studies may therefore be of little relevance to individual patients, they continue to inform our understanding of tumour biology.     

Atlanto-axial rotatory fixation: Improved demonstration using spiral CT

Atlanto-axial rotatory fixation (AARF) is an uncommon condition which is often missed at presentation because of its rarity and the relative subtlety of plain film X-ray findings, but early detection and appropriate management are vital for a cure. We describe three cases in which the use of spiral computed tomography scanning with 3D and sagittal reconstructions greatly aided diagnosis and management. The 3D images gave a more graphic picture of the overall alignment of the upper cervical spine and the skull base, while the sagittal reconstructions demonstrated the presence or absence of compensatory atlanto-occipital subluxation. The literature is briefly reviewed.     

The lens in hereditary hyperferritinaemia cataract syndrome contains crystalline deposits of L-ferritin

BACKGROUND/AIM: Hereditary hyperferritinaemia cataract syndrome (HHCS) is an autosomal dominant disorder characterised by elevated serum L-ferritin and bilateral cataracts. The ocular manifestations of this disorder are poorly studied. This study therefore sought to determine the origin of cataracts in HHCS. METHODS: L-ferritin ELISA, immunohistochemical and ultrastructural analysis of a lens nucleus from an HHCS individual. RESULTS: The HHCS lens L-ferritin content was 147 microg/g dry weight of lens compared with <16 microg/g for a non-HHCS control cataract lens. The cataract comprised discrete crystalline inclusions with positive staining with anti-L-ferritin but not anti-H-ferritin. CONCLUSIONS: This unusual finding of crystalline opacities in the lens may be unique to HHCS and is likely to result from disturbed metabolism of L-ferritin within the lens or an abnormal interaction between L-ferritin and lens proteins.     

Vascular endothelial growth factor is elevated in ocular fluids of eyes harbouring uveal melanoma: identification of a potential therapeutic window

BACKGROUND: Improved local treatment of uveal melanoma makes it possible for many patients to retain the affected eye, but a proportion will develop secondary complications such as neovascularisation of the iris (NVI) and require enucleation. Although vascular endothelial growth factor A (VEGF-A) is known to correlate with NVI and can cause NVI in experimental models, this pro-angiogenic cytokine is consistently reported to be absent in uveal melanoma. Novel anti-VEGF therapies are now in clinical trial, and the authors therefore wished to determine whether VEGF-A was indeed elevated in melanoma bearing eyes. METHODS: VEGF-A concentrations were measured in aqueous and vitreous from 19 and 30 enucleated eyes respectively. RESULTS: Elevated VEGF-A concentrations (up to 21.6 ng/ml) were found in melanoma bearing eyes compared with samples from patients undergoing routine cataract extraction (all had values below 0.96 ng/ml). Immunohistochemistry showed VEGF-A protein in the iris and/or ciliary body of 54% and basic fibroblast growth factor (bFGF) in 82% of the eyes examined. VEGF was found to a limited extent and at very low levels in only 9% of these tumours. Aqueous or vitreous VEGF levels showed no apparent correlation with retinal detachment, tumour size, vascularity, or immunohistochemistry. Though limited in number, the highest VEGF levels correlated with previous radiation therapy, and with the presence neovascularisation of the iris or optic nerve head. bFGF was not significantly elevated in ocular fluids: it is known to be a pro-angiogenic agent and was detected in the majority of primary uveal melanomas. CONCLUSION: Based on this study, though the source of VEGF within eyes harbouring uveal melanoma is not clear, these data suggest that anti-VEGF therapy might prove useful in the management of some patients with NVI secondary to uveal melanoma.     

Primary orbital melanoma masquerading as vascular anomalies

PURPOSE: To review two cases of primary orbital melanoma presenting like orbital vascular anomalies. METHODS: Retrospective review of clinical presentation, treatment, radiology and pathology for two patients under the care of the Orbital Clinic at Moorfields Eye Hospital. RESULTS: Both lesions presented with the appearance and behaviour of vascular anomalies. In one case, a spindle cell melanoma appeared to be a low flow vascular anomaly with a loculated secondary haemorrhage and, in the other case, a melanoma of soft parts was considered to be an arteriovenous malformation and responded partially to embolisation. CONCLUSION: Primary malignant melanoma may present as a secondary vascular lesion of the orbit and this very rare tumour should be considered in the differential diagnosis of any vascular anomaly.     

Chemosensitization of solid tumor cells by alteration of their susceptibility to apoptosis

Chemosensitization strategies use the administration of one drug or agent to render cancer cells more susceptible to a second agent. Usually this involves enhanced drug metabolism, improvement of drug uptake or blockage of resistance mechanisms. Alteration of the susceptibility of cancer cells to apoptosis, the process of individual cell death by which many chemotherapeutic drugs act, shows particular promise for therapy in the future, and is the focus of this review. The dependence of cancer cells on non-neoplastic cells to form solid tumors allows anti-angiogenic therapy to be used in conjunction with chemotherapy to increase the therapeutic index. Chemosensitization strategies are set to become increasingly important in cancer therapy, allowing rational design of synergistic drug combinations at an earlier stage in drug development.