Assignment of the 5-hydroxytryptamine (serotonin) receptor 5A gene (HTR5A) to human chromosome band 7q36.1

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Localization of the human dihydrolipoamide dehydrogenase gene (DLD) to 7q31→q32

The gene for human dihydrolipoamide dehydrogenase (DLD) has been localized to the long arm of chromosome 7, within bands q31→q32, by gel-blot hybridization analysis with DNA from a panel of somatic cell hybrids containing various portions of human chromosome 7.published_or_final_versio

New Approaches to Photodynamic Therapy from Type I, II and III to Type IV Using One or More Photons

Photodynamic therapy (PDT) is an alternative cancer treatment to conventional surgery, radiotherapy and chemotherapy. It is based on activating a drug with light that triggers the generation of cytotoxic species that promote tumour cell killing. At present, PDT is mainly used in the treatment of wet age-related macular degeneration, for precancerous conditions of the skin (e.g. actinic keratosis) and in the palliative care of advanced cancers, for instance of the bladder or the oesophagus. PDT is still not used as a first line cancer treatment, which is surprising given the first clinical trials by Dougherty’s group dating back to the 1970’s. PDT has significant advantages over surgery or radiation therapy for low lying tumours due to better cosmetic outcome and localised treatment for the patients. However, despite these advantages and significant developments in optical technology that has enabled light penetration to deeper lying tumours, in excess of 5 cm, a lack of phase III clinical trials has slowed down the uptake of PDT by the healthcare sector as a frontline treatment in cancer. However research continues to demonstrate the potential benefits of PDT and the need to stimulate funding and uptake of clinical studies using next generation photosensitizers offering advanced targeted delivery, improved photodynamic dose combined with modern light delivery technologies. This review surveys the available PDT treatments and emerging novel developments in the field with a particular focus on two-photon techniques that are anticipated to improve the effectiveness of PDT in tissues at depth and on next generation drugs that work without the need of the presence of oxygen for photosensitization making them effective where hypoxia has taken hold

A novel method for high-throughput detection and quantification of neutrophil extracellular traps reveals ROS-independent NET release with immune complexes

AbstractA newly-described first-line immune defence mechanism of neutrophils is the release of neutrophil extracellular traps (NETs). Immune complexes (ICxs) induce low level NET release. As such, the in vitro quantification of NETs is challenging with current methodologies. In order to investigate the role of NET release in ICx-mediated autoimmune diseases, we developed a highly sensitive and automated method for quantification of NETs. After labelling human neutrophils with PKH26 and extracellular DNA with Sytox green, cells are fixed and automatically imaged with 3-dimensional confocal laser scanning microscopy (3D-CLSM). NET release is then quantified with digital image analysis whereby the NET amount (Sytox green area) is corrected for the number of imaged neutrophils (PKH26 area). A high sensitivity of the assay is achieved by a) significantly augmenting the area of the well imaged (11%) as compared to conventional assays (0.5%) and b) using a 3D imaging technique for optimal capture of NETs, which are topologically superimposed on neutrophils. In this assay, we confirmed low levels of NET release upon human ICx stimulation which were positive for citrullinated histones and neutrophil elastase. In contrast to PMA-induced NET release, ICx-induced NET release was unchanged when co-incubated with diphenyleneiodonium (DPI). We were able to quantify NET release upon stimulation with serum from RA and SLE patients, which was not observed with normal human serum. To our knowledge, this is the first semi-automated assay capable of sensitive detection and quantification of NET release at a low threshold by using 3D CLSM. The assay is applicable in a high-throughput manner and allows the in vitro analysis of NET release in ICx-mediated autoimmune diseases

Refined localization of the asparagine synthetase gene (ASNS) to chromosome 7, region q21.3, and characterization of the somatic cell hybrid line 4AF/106/K015

We have mapped the asparagine synthetase gene (ASNS) to 7q21.3 by fluorescence in situ hybridization. While this study refined the localization of the gene, it also revealed a rearrangement in a somatic cell hybrid line which was used in previous ASNS mapping. Using additional probes from other regions of human chromosome 7, we showed that this cell line (4AF/106/KO15) contained a rearranged chromosome 7 in which a segment of the long arm was apparently duplicated and inserted into the short arm. Caution should be used therefore when interpreting data obtained from this cell line for gene mapping studies.published_or_final_versio

Molecular definition of a narrow interval at 7q22.1 associated with myelodysplasia

Chromosome 7 translocations, deletions, or monosomy are associated with myelodysplasia (MDS) and acute myeloid leukemia both in children and adults. These chromosomal anomalies represent one of the most common cytogenetic abnormalities associated with these diseases and usually herald a poor prognosis. In this study two cosmid DNA probes that mapped to 7q22.1 and were known to be separated by approximately 500 kb were identified to flank the proximal inversion breakpoint in a patient carrying a constitutional inversion (7q22.1-34) associated with MDS. A yeast artificial chromosome (YAC) clone that encompassed the two cosmids was identified and shown to span the breakpoint. Fluorescence in situ hybridization was then used to analyze six additional patients with myelodysplasia and chromosomal rearrangements of the 7q22 region (three patients had translocations and three carried deletions). The breakpoint in one of the patients was found to be contained within the same YAC clone that spanned the inversion breakpoint. Moreover, this same interval was determined to be absent in all three patients with chromosomal deletions. These results suggest that this segment of DNA on chromosome 7q22.1 may contain specific gene(s) that have a significant role in myeloid malignancies.link_to_OA_fulltex

Hemizygous deletion of the syntaxin 1A gene in individuals with Williams syndrome: Letters to the editor

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Time-resolved nanosecond fluorescence lifetime imaging and picosecond infrared spectroscopy of combretastatin A-4 in solution and in cellular systems

Fluorescence lifetime images of intrinsic fluorescence obtained with two-photon excitation at 630 nm are shown following uptake of a series of E-combretastatins into live cells, including human umbilical vein endothelial cells (HUVECs) that are the target for the anticancer activity of combretastatins. Images show distribution of the compounds within the cell cytoplasm and in structures identified as lipid droplets by comparison with images obtained following Nile red staining of the same cells. The intracellular fluorescent lifetimes are generally longer than in fluid solution as a consequence of the high viscosity of the cellular environment. Following incubation the intracellular concentrations of a fluorinated derivative of E combretastatin A4 in HUVECs are up to between 2 and 3 orders of magnitude higher than the concentration in the surrounding medium. Evidence is presented to indicate that at moderate laser powers (up to 6 mW) it is possible to isomerize up to 25% of the combretastatin within the femtolitre focal volume of the femtosecond laser beam. This suggests that it may be possible to activate the E-combretastatin (with low cellular toxicity) to the Z-isomer with high anticancer drug activity using two-photon irradiation. The isomerization of Z- and E-combretastatins by 266 nm irradiation has been probed by ultrafast time-resolved infrared spectroscopy. Results for the E-isomer show a rapid loss of excess vibrational energy in the excited state with a lifetime of 7 ps, followed by a slower process with a lifetime of 500 ps corresponding to the return to the ground state as also determined from the fluorescence lifetime. In contrast the Z-isomer, whilst also appearing to undergo a rapid cooling of the initial excited state, has a much shorter overall excited state lifetime of 14 ps

Molecular cytogenetic delineation of deletions and translocations involving chromosome band 7q22 in myeloid leukemias

Loss of chromosome 7 (-7) or deletion of its long arm (7q-) are recurring chromosome abnormalities in myeloid disorders, especially in therapy-related myelodysplastic syndrome (t-MDS) and acute myeloid leukemia (t-AML). The association of -7/7q- with myeloid leukemia suggests that these regions contain a novel tumor suppressor gene(s) whose loss of function contributes to leukemic transformation or tumor progression. Based on chromosome banding analysis, two critical regions have been identified: one in band 7q22 and a second in bands 7q32-q35. We analyzed bone marrow and blood samples from 21 patients with myeloid leukemia (chronic myeloid leukemia, n = 2; de novo MDS, n = 4; de novo AML, n = 13: t-AML, n = 2) that on chromosome banding analysis exhibited deletions (n = 19) or reciprocal translocations (n = 2) of band 7q22 using fluorescence in situ hybridization. As probes, we used Alu-polymerase chain reaction products from 22 yeast artificial chromosome (YAC) clones that span chromosome bends 7q21.1-q32, including representative clones from a panel of YACs recognizing a contiguous genomic DNA fragment of 5 to 6 Mb in band 7q22. In the 19 cases with deletions, we identified two distinct commonly deleted regions: one region within band 7q22 was defined by the two CML cases; the second region encompassed a distal part of band 7q22 and the entire band 7q31 and was defined by the MDS/AML cases. The breakpoint of one of the reciprocal translocations was mapped to 7q21.3, which is centromeric to both of the commonly deleted regions. The breakpoint of the second translocation, which was present in unstimulated bone marrow and phytohemagglutinin-stimulated blood of an MDS patient, was localized to a 400-kb genomic segment in 7q22 within the deletion cluster of the MDS/AML cases. In conclusion, our data show marked heterogeneity of 7q22 deletion and translocation breakpoints in myeloid leukemias, suggesting the existence of more than one pathogenetically relevant gene.link_to_OA_fulltex

Involvement of the HLXB9 homeobox gene in Currarino syndrome [2]

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