Development of photoreceptor-specific promoters and their utility to investigate EIAV lentiviral vector mediated gene transfer to photoreceptors

BACKGROUND: We wanted to investigate the ability of recombinant equine infectious anemia virus (EIAV) vectors to transduce photoreceptor cells by developing a series of photoreceptor-specific promoters that drive strong gene expression in photoreceptor cells. METHODS: Promoter fragments derived from the rhodopsin (RHO), the beta phosphodiesterase (PDE) and the retinitis pigmentosa (RP1) genes were cloned in combination with an enhancer element, derived from the interphotoreceptor retinoid-binding protein gene (IRBP), into luciferase reporter plasmids. An in vitro transient reporter assay was carried out in the human Y-79 retinoblastoma cell line. The optimal promoters from this screen were then cloned into the recombinant EIAV vector for evaluation in vivo following subretinal delivery into mice. RESULTS: All promoters maintained a photoreceptor-specific expression profile in vitro and the gene expression was further enhanced in combination with the IRBP enhancer. The use of IRBP-combined RHO or PDE promoters showed modest but exclusive expression in photoreceptors following subretinal delivery to mice. By contrast an EIAV vector containing the cytomegalovirus (CMV) promoter drove reporter gene expression in both photoreceptors and retinal pigment epithelium. CONCLUSIONS: It may be possible to use recombinant EIAV vectors containing photoreceptor-specific promoters to drive therapeutic gene expression to treat a range of retinal degenerative diseases where the photoreceptor cell is the primary disease target.     

CETACEAN OCCURRENCE PATTERNS IN THE AMUNDSEN AND SOUTHERN BELLINGSHAUSEN SEA SECTOR, SOUTHERN OCEAN

We conducted 239.5 h and 3,494 km of cetacean surveys in the Amundsen and Bellingshausen seas, from 15 February to 31 March 1994; most of the area, the large portion of which was ice covered, had never before nor has it since been surveyed for cetaceans, even to the date when this paper was prepared (2006). Logistic regression and an information-theoretic approach related the occurrence of Antarctic minke whales Balaenoptera bonaerensis (the most abundant species) to whether we were in open- or pack-ice-covered pelagic or neritic waters, in or out of the marginal ice zone (MIZ), and north or south of the Antarctic Circumpolar Current southern boundary. Other variables included date and distance to the MIZ and shelfbreak front. Statistical analysis showed that the probability of sighting a minke, as well as killer whale—but not the case for an index to whale density—was related to the proximity of coastal polynyas in early autumn, switching offshore to the MIZ once waters within the pack began to freeze persistently later in the season. Probability of detection was higher with distance into the MIZ. Supporting these findings, the density index was strongly related to ice concentration in an inverse relationship. The strong relationship to polynyas and the MIZ indicate that sea-ice divergence altered by decadal or longer-term climate change, as described in the recent literature, could well affect any apparent, long-term trends evident in this species' abundance if surveyed only in open or near-to-ice waters. We speculate on how the minke whale's pagophilic nature (1) could have been encouraged by large-scale industrial whaling and by competition with species more characteristic of open waters and the outer MIZ, and (2) may have protected the population somewhat during industrial whaling resulting in the much greater abundance of this species now compared to other targeted species.     

Dopamine mediates context-dependent modulation of sensory plasticity in C. elegans

Dopamine has been implicated in the modulation of diverse forms of behavioral plasticity, including appetitive learning and addiction. An important challenge is to understand how dopamine's effects at the cellular level alter the properties of neural circuits to modify behavior. In the nematode C. elegans, dopamine modulates habituation of an escape reflex triggered by body touch. In the absence of food, animals habituate more rapidly than in the presence of food; this contextual information about food availability is provided by dopaminergic mechanosensory neurons that sense the presence of bacteria. We find that dopamine alters habituation kinetics by selectively modulating the touch responses of the anterior-body mechanoreceptors; this modulation involves a D1-like dopamine receptor, a Gq/PLC-beta signaling pathway, and calcium release within the touch neurons. Interestingly, the body touch mechanoreceptors can themselves excite the dopamine neurons, forming a positive feedback loop capable of integrating context and experience to modulate mechanosensory attention.     

Quality control of human tissues-experience from the Indiana University Cancer Center-Lilly Research Labs human tissue bank

The success of molecular research and its applications in both the clinical and basic research arenas is strongly dependent on the collection, handling, storage, and quality control of fresh human tissue samples. This tissue bank was set up to bank fresh surgically obtained human tissue using a Clinical Annotated Tissue Database (CATD) in order to capture the associated patient clinical data and demographics using a one way patient encryption scheme to protect patient identification. In this study, we determined that high quality of tissue samples is imperative for both genomic and proteomic molecular research. This paper also contains a brief compilation of the literature involved in the patient ethics, patient informed consent, patient de-identification, tissue collection, processing, and storage as well as basic molecular research generated from the tissue bank using good clinical practices. The current applicable rules, regulations, and guidelines for handling human tissues are briefly discussed. More than 6,610 cancer patients have been consented (97% of those that were contacted by the consenter) and 16,800 tissue specimens have been banked from these patients in 9 years. All samples collected in the bank were QC’d by a pathologist. Approximately 1,550 tissue samples have been requested for use in basic, clinical, and/or biomarker cancer research studies. Each tissue aliquot removed from the bank for a research study were evaluated by a second H&E, if the samples passed the QC, they were submitted for genomic and proteomic molecular analysis/study. Approximately 75% of samples evaluated were of high histologic quality and used for research studies. Since 2003, we changed the patient informed consent to allow the tissue bank to gather more patient clinical follow-up information. Ninety two percent of the patients (1,865 patients) signed the new informed consent form and agreed to be re-contacted for follow-up information on their disease state. In addition, eighty five percent of patients (1,584) agreed to be re-contacted to provide a biological fluid sample to be used for biomarker research.     

Checkpoint independence of most DNA replication origins in fission yeast

Background

In budding yeast, the replication checkpoint slows progress through S phase by inhibiting replication origin firing. In mammals, the replication checkpoint inhibits both origin firing and replication fork movement. To find out which strategy is employed in the fission yeast, Schizosaccharomyces pombe, we used microarrays to investigate the use of origins by wild-type and checkpoint-mutant strains in the presence of hydroxyurea (HU), which limits the pool of deoxyribonucleoside triphosphates (dNTPs) and activates the replication checkpoint. The checkpoint-mutant cells carried deletions either of rad3 (which encodes the fission yeast homologue of ATR) or cds1 (which encodes the fission yeast homologue of Chk2).

Results

Our microarray results proved to be largely consistent with those independently obtained and recently published by three other laboratories. However, we were able to reconcile differences between the previous studies regarding the extent to which fission yeast replication origins are affected by the replication checkpoint. We found (consistent with the three previous studies after appropriate interpretation) that, in surprising contrast to budding yeast, most fission yeast origins, including both early- and late-firing origins, are not significantly affected by checkpoint mutations during replication in the presence of HU. A few origins (~3%) behaved like those in budding yeast: they replicated earlier in the checkpoint mutants than in wild type. These were located primarily in the heterochromatic subtelomeric regions of chromosomes 1 and 2. Indeed, the subtelomeric regions defined by the strongest checkpoint restraint correspond precisely to previously mapped subtelomeric heterochromatin. This observation implies that subtelomeric heterochromatin in fission yeast differs from heterochromatin at centromeres, in the mating type region, and in ribosomal DNA, since these regions replicated at least as efficiently in wild-type cells as in checkpoint-mutant cells.

Conclusion

The fact that ~97% of fission yeast replication origins – both early and late – are not significantly affected by replication checkpoint mutations in HU-treated cells suggests that (i) most late-firing origins are restrained from firing in HU-treated cells by at least one checkpoint-independent mechanism, and (ii) checkpoint-dependent slowing of S phase in fission yeast when DNA is damaged may be accomplished primarily by the slowing of replication forks.     

Severe upper airway obstruction due to delayed retropharyngeal hematoma formation following blunt cervical trauma

Background

We report a case of severe upper airway obstruction due to a retropharyngeal hematoma that presented nearly one day after a precipitating traumatic injury. Retropharyngeal hematomas are rare, but may cause life-threatening airway compromise.

Case presentation

A 50 year-old man developed severe dyspnea with oropharyngeal airway compression due to retropharyngeal hematoma 20 hours after presenting to the emergency department. The patient also had a fractured first cervical vertebra and was diagnosed with a left brachial plexopathy. The patient underwent emergent awake fiberoptic endotracheal intubation to provide a definitive airway.

Conclusion

Retropharyngeal hematoma with life-threatening airway compromise can develop hours or days after a precipitating injury. Clinicians should be alert to the potential for this delayed airway collapse, and should also be prepared to rapidly secure the airway in this patient population likely to have concomitant cervical spinal or head injuries.