Pupillary dysfunction in myasthenia gravis.

The constriction-dilation cycles of pupils exposed to a stationary, discrete slit-lamp beam were significantly prolonged in 25 myasthenic patients (1,060.4 +/- 45.8 msec) undergoing therapy with steroids, anticholinesterases, or both, compared to normal controls (801.9 +/- 8.6 msec) or subjects receiving steroids for nonneurological disease (860.9 +/- 14.9 msec). The duration of myasthenia correlated with the slowing of the cycle time. Myasthenia gravis may affect ectodermally derived smooth muscle or the autonomic neuromuscular junction or both, and not be restricted to the well-demonstrated alterations of neuromuscular junction in striated muscle of mesodermal origin. Alternatively, prolonged pupillary cycles could be attributed to dysfunction of central pathways of the pupillary light reflex.     

CpG island promoter hypermethylation of a novel Ras-effector gene RASSF2A is an early event in colon carcinogenesis and correlates inversely with K-ras mutations

We report in silico identification and characterisation of a novel member of the ras association domain family 1 (RASSF1)/NORE1 family, namely, RASSF2, located at chromosomal region 20p13. It has three isoforms, all contain a ras association domain in the C-terminus. The longest isoform RASSF2A contains a 5' CpG island. RASSF2A was cloned from a brain cDNA library and directly sequenced, confirming the genomic gene structure. In previous reports, we and others have demonstrated that RASSF1A is epigenetically inactivated in a variety of cancers, including sporadic colorectal cancer (CRC). In the present report, we analysed the methylation status of RASSF2A promoter region CpG island in sporadic CRC and compared it to K-ras mutation status. RASSF2A promoter region CpG island was hypermethylated in a majority of colorectal tumour cell lines (89%) and in primary colorectal tumours (70%), while DNA from matched normal mucosa was found to be unmethylated (tumour-specific methylation). RASSF2A expression was reactivated in methylated tumour cell lines after treatment with 5-aza 2-deoxycytidine. RASSF2A methylation is an early event, detectable in 7/8 colon adenomas. Furthermore, 75% of colorectal tumours with RASSF2A methylation had no K-ras mutations (codons, 12 and 13) (P=0.048), Fisher's exact test). Our data demonstrate that RASSF2A is frequently inactivated in CRCs by CpG island promoter hypermethylation, and that epigenetic (RASSF2A) and genetic (K-ras) changes are mutually exclusive and provide alternative pathways for affecting Ras signalling.     

Identification of novel VHL target genes and relationship to hypoxic response pathways

Upregulation of hypoxia-inducible factors HIF-1 and HIF-2 is frequent in human cancers and may result from tissue hypoxia or genetic mechanisms, in particular the inactivation of the von Hippel-Lindau (VHL) tumour suppressor gene (TSG). Tumours with VHL inactivation are highly vascular, but it is unclear to what extent HIF-dependent and HIF-independent mechanisms account for pVHL tumour suppressor activity. As the identification of novel pVHL targets might provide insights into pVHL tumour suppressor activity, we performed gene expression microarray analysis in VHL-wild-type and VHL-null renal cell carcinoma (RCC) cell lines. We identified 30 differentially regulated pVHL targets (26 of which were 'novel') and the results of microarray analysis were confirmed in all 11 novel targets further analysed by real-time RT-PCR or Western blotting. Furthermore, nine of 11 targets were dysregulated in the majority of a series of primary clear cell RCC with VHL inactivation. Three of the nine targets had been identified previously as candidate TSGs (DOC-2/DAB2, CDKN1C and SPARC) and all were upregulated by wild-type pVHL. The significance for pVHL function of two further genes upregulated by wild-type pVHL was initially unclear, but re-expression of GNG4 (G protein gamma-4 subunit/guanine nucleotide-binding protein-4) and MLC2 (myosin light chain) in a RCC cell line suppressed tumour cell growth. pVHL regulation of CDKN1C, SPARC and GNG4 was not mimicked by hypoxia, whereas for six of 11 novel targets analysed (including DOC-2/DAB2 and MLC2) the effects of pVHL inactivation and hypoxia were similar. For GPR56 there was evidence of a tissue-specific hypoxia response. Such a phenomenon might, in part, explain organ-specific tumorigenesis in VHL disease. These provide insights into mechanisms of pVHL tumour suppressor function and identify novel hypoxia-responsive targets that might be implicated in tumorigenesis in both VHL disease and in other cancers with HIF upregulation.     

Improvement of bilateral motor functions in patients with Parkinson disease through the unilateral intraputaminal infusion of glial cell line-derived neurotrophic factor

OBJECT: Glial cell line-derived neurotrophic factor (GDNF) has demonstrated significant antiparkinsonian actions in several animal models and in a recent pilot study in England in which four of five patients received bilateral putaminal delivery. In the present study the authors report on a 6-month unilateral intraputaminal GDNF infusion in 10 patients with advanced Parkinson disease (PD). METHODS: Patients with PD in a functionally defined on and off state were evaluated 1 week before and 1 and 4 weeks after intraputaminal catheter implantation in the side contralateral to the most affected side. Each patient was placed on a dose-escalation regimen of GDNF: 3, 10, and 30 microg/day at successive 8-week intervals, followed by a 1-month wash-out period. The Unified Parkinson's Disease Rating Scale (UPDRS) total scores in the on and off states significantly improved 34 and 33%, respectively, at 24 weeks compared with baseline scores (95% confidence interval [CI] 18-47% for off scores and 16-51% for on scores). In addition, UPDRS motor scores in both the on and off states significantly improved by 30% at 24 weeks compared with baseline scores (95% CI 15-48% for off scores and 5-61% for on scores). Improvements occurred bilaterally, as measured by balance and gait and increased speed of hand movements. All significant improvements of motor function continued through the wash-out period. The only observed side effects were transient Lhermitte symptoms in two patients. CONCLUSIONS: Analysis of the data in this open-label study demonstrates the safety and potential efficacy of unilateral intraputaminal GDNF infusion. Unilateral administration of the protein resulted in significant, sustained bilateral effects.     

Knowledge, awareness, and use of the UV index amongst the West Australian public

The ultraviolet (UV) index provides an opportunity to warn people about the degree of hazard that exists on a particular day and subsequently lead to the adoption of sun protective behaviors. While the UV index has been promoted in Australia for some time, little research has been conducted into the understanding and use of the index. As such, a random telephone survey of 501 adults was conducted in December 1999 to gather data into the public's understanding and use of the UV index in Perth, Australia. A high awareness of the UV index existed among the respondents, with 90% indicating they had heard of the term UV index. However, only 5% indicated they had noticed the UV index/forecast for that particular day. The results indicate that a campaign to increase awareness of the UV index by the public is not warranted, but that efforts should be focused on developing tools to communicate behavior change messages linked to the UV index levels. The research was conducted with funding from Healthway, Health Promotion Foundation of Western Australia.     

RASSF1A interacts with microtubule-associated proteins and modulates microtubule dynamics

The candidate tumor suppressor gene RASSF1A is inactivated in many types of adult and childhood cancers. However, the mechanisms by which RASSF1A exerts its tumor suppressive functions have yet to be elucidated. To this end, we performed a yeast two-hybrid screen to identify novel RASSF1A-interacting proteins in a human brain cDNA library. Seventy percent of interacting clones had homology to microtubule-associated proteins, including MAP1B and VCY2IP1/C19ORF5. RASSF1A association with MAP1B and VCY2IP1/C19ORF5 was subsequently confirmed in mammalian cell lines. This suggested that RASSF1A may exert its tumor-suppressive functions through interaction with the microtubules. We demonstrate that RASSF1A associates with the microtubules, causing them to exist as hyperstabilized circular bundles. We found that two naturally occurring tumor-associated missense substitutions in the RASSF1A coding region, C65R and R257Q, perturb the association of RASSF1A with the microtubules. The C65R and R257Q in addition to VCY2IP1/C19ORF5 showed reduced ability to induce microtubule acetylation and were unable to protect the microtubules against the depolymerizing action of nocodazole. In addition, wild-type RASSF1A but not the C65R or the R257Q is able to block DNA synthesis. Our data identify a role for RASSF1A in the regulation of microtubules and cell cycle dynamics that could be part of the mechanism(s) by which RASSF1A exerts its growth inhibition on cancer cells.     

Case report: radical radiotherapy for early laryngeal cancer in a patient with human immunodeficiency virus: no evidence of increased toxicity

There are very few reported cases of laryngeal squamous cell carcinoma (SCC) in patients with a background of human immunodeficiency virus (HIV) infection. We report a case of a 42-year-old man who developed a T2 N0 left vocal cord well differentiated SCC with an 11 year history of HIV infection. He successfully completed a course of radical radiotherapy 66 Gy in 33 fractions over 47 days. During his treatment he experienced only a grade 1 Radiation Therapy Oncology Group (RTOG) acute toxicity reaction to the larynx and no weight loss. At 32 months follow up he remains disease free and has no significant late morbidity. Prior to his radiotherapy his CD4 count was 350 cells mm(-3); we discuss the view that the treatment chosen needs to be individually tailored with respect to the patient's immune status.     

Epigenetic risks related to assisted reproductive technologies: epigenetics, imprinting, ART and icebergs?

Recently, a series of case reports and small studies has suggested that births involving assisted reproductive technology (ART) may have an increased risk of imprinting disorders such as Beckwith-Wiedemann syndrome and Angelman syndrome. Herein, the significance and implications of these findings are discussed. It is speculated that, although such imprinting disorders may be shown to be only rare complications of ART, epigenetic errors might account for a much wider spectrum of ART-related complications than is recognized currently. Addressing these questions should be a priority for research on cohorts of ART children.     

Ionotropic glutamate receptor biology: effect on synaptic connectivity and function in neurological disease

Glutamate receptor signaling is essential to normal synaptic function in the central nervous system. The major ionotropic glutamate receptors (AMPA, Kainic, and NMDA) have different synaptic functions depending upon cellular and subcellular localization, subunit composition, and second messenger systems linked to the receptors. In this review, we examine major advances in glutamate receptor biology whose physiology plays a central role in neurologic disease such as epilepsy and stroke. A key feature of glutamate receptor activation in neurologic disease is the downstream effects on cell survival, genetic expression of axon guidance cues, synaptic connectivity/formation of networks, and neuronal excitability. Identification of therapeutic pharmacologic targets and development of antagonists specific to the disease process remain central themes in epilepsy and stroke research.