Construction of a consistent YAC contig for human chromosome region 3p14.1

Chromosomal deletions and translocations of human chromosome region 3p14 are observed in various human malignancies and suggest the existence of a tumor suppressor gene locus within this region. Tumors most frequently affected by these aberrations are small-cell lung cancer and renal-cell carcinoma. In continuation of our previously published YAC contig of chromosome region 3p14.2-p14.3, we report here on the construction of a YAC contig of at least 11 Mb that consisted of 171 YACs and covers the entire subregion 3p14.1. This contig includes the t(3;8) breakpoint of a hereditary renal-cell carcinoma localized in 3p14.2 and extends into human chromosome region 3p12-p13. It defines the order of 34 DNA probes in relation to reference markers D3S6 and D3S30 as well as the human protein tyrosine phosphatase-gamma gene. For 31 DNA probes we identified nonchimeric YACs by fluorescence in situ hybridization. The minimal tiling pathway consists of 16 yeast artificial chromosomes. As a prerequisite for identification of a putative tumor suppressor gene within this region, this contig renders human chromosome region 3p14.1 accessible to gene isolation

Tetrahydrouridine Inhibits Cell Proliferation through Cell Cycle Regulation Regardless of Cytidine Deaminase Expression Levels

Tetrahydrouridine (THU) is a well characterized and potent inhibitor of cytidine deaminase (CDA). Highly expressed CDA catalyzes and inactivates cytidine analogues, ultimately contributing to increased gemcitabine resistance. Therefore, a combination therapy of THU and gemcitabine is considered to be a potential and promising treatment for tumors with highly expressed CDA. In this study, we found that THU has an alternative mechanism for inhibiting cell growth which is independent of CDA expression. Three different carcinoma cell lines (MIAPaCa-2, H441, and H1299) exhibited decreased cell proliferation after sole administration of THU, while being unaffected by knocking down CDA. To investigate the mechanism of THU-induced cell growth inhibition, cell cycle analysis using flow cytometry was performed. This analysis revealed that THU caused an increased rate of G1-phase occurrence while S-phase occurrence was diminished. Similarly, Ki-67 staining further supported that THU reduces cell proliferation. We also found that THU regulates cell cycle progression at the G1/S checkpoint by suppressing E2F1. As a result, a combination regimen of THU and gemcitabine might be a more effective therapy than previously believed for pancreatic carcinoma since THU works as a CDA inhibitor, as well as an inhibitor of cell growth in some types of pancreatic carcinoma cells

Chronic Hiccups: An Underestimated Problem

Persistent singultus, hiccupping that lasts for longer than 48 hours, can have a tremendous impact on a patient's quality of life. Although involved neurologic structures have been identified, the function of hiccups remains unclear they have been controversially interpreted as a primitive reflex preventing extent swallowing of amniotic fluid in utero, an archaic gill ventilation pattern, or a fetus' preparation for independent breathing. Persistent singultus often presents as a symptom for various diseases, most commonly illnesses of the central nervous system or gastrointestinal tract; they can also be evoked by a variety of pharmacological agents. It is often impossible to define a singular cause. A wide range of treatment attempts, pharmacological and nonpharmacological, have been concerted to this date; however, chlorpromazine remains the only Food and Drug Administration approved drug in this context. Large-scale studies on efficacy and tolerance of other therapeutic strategies are lacking. Gabapentin, baclofen, and metoclopramide have been reported to accomplish promising results in reports on the therapy of persistent singultus; they may also be effective when given in combination with other drugs, eg, proton pump inhibitors, or as conjoined therapy. As another approach of note, acupuncture treatment was able to abolish hiccups in a number of studies. When managing hiccup patients within the clinical routine, it is of importance to conduct a comprehensive and effective diagnostic workup; a well-functioning interdisciplinary team is needed to address possible causes for the symptom. Persistent singultus is a medical problem not to be underestimated; more research on options for effective treatment would be greatly neede