PyA-cluster system for the detection and imaging of miRNAs in living cells through double-three-way junction formation

Herein, we describe an extended version of a fluorescence probe for detecting miRNAs through the novel application of a ^PyA-cluster system. By testing various (CG)_n sequences in the middle of the oligonucleotide strand of the probe, we obtained an optimal sequence that formed a double-three-way-junction structure, with two ^PyA units positioned close together, in the presence of the target miRNA. This system readily detected the locations of target miRNAs in living cells and allowed visualization of structural changes through variations in the color of the fluorescence.

Pentacyclic adenine: a versatile and exceptionally bright fluorescent DNA base analogue

A highly fluorescent, non-perturbing, pentacyclic adenine analog was designed, synthesized, incorporated into DNA and photophysical evaluated.

Emissive base analogs are powerful tools for probing nucleic acids at the molecular level. Herein we describe the development and thorough characterization of pentacyclic adenine (pA), a versatile base analog with exceptional fluorescence properties. When incorporated into DNA, pA pairs selectively with thymine without perturbing the B-form structure and is among the brightest nucleobase analogs reported so far. Together with the recently established base analog acceptor qA_nitro, pA allows accurate distance and orientation determination via Förster resonance energy transfer (FRET) measurements. The high brightness at emission wavelengths above 400 nm also makes it suitable for fluorescence microscopy, as demonstrated by imaging of single liposomal constructs coated with cholesterol-anchored pA–dsDNA, using total internal reflection fluorescence microscopy. Finally, pA is also highly promising for two-photon excitation at 780 nm, with a brightness (5.3 GM) that is unprecedented for a base analog.

Detection of cofilin mRNA by hybridization-sensitive double-stranded fluorescent probes

We have developed hybridization-sensitive fluorescent oligonucleotide probes that, in the presence of quencher strands, undergo efficient fluorescence quenching through the formation of partial DNA/DNA duplexes.

Fluorescence properties of 6-aryl-2'-deoxy-furanouridine and -pyrrolocytidine and their derivatives

2'-deoxyfuranouridine derivatives presenting various aryl groups have been synthesized through Cu(I)-catalyzed intramolecular cyclizations. Moreover, corresponding pyrrolo-dC derivatives have been synthesized and both families of compounds thoroughly characterized using UV/vis and fluorescence spectroscopy as well as time-dependent density functional theory calculations. The photophysical characterization, show that our newly synthesized derivatives of the important pyrrolo-dC family have high fluorescence quantum yields (QYs) and brightness values. Pyrrolo-dC derivative, 3a, shows an environment sensitive QY of up to >60% and brightness of almost 3000, in low polarity solvents and excitation and emission maxima between 365-381 nm and 479-510 nm, respectively, in solvents of different polarities. Two other derivatives, 3b and 3c, show high QYs and brightness values of up to 3300 that are fairly insensitive to their microenvironment. These promising photophysical features suggest future applicability as fluorescent nucleobase analogs.

Primary malignant teratoma of the thyroid gland: report and discussion of two cases

BACKGROUND

Teratoma of the thyroid in adults is a rare neoplasm and is usually seen in young females. Most of the thyroid teratoma are malignant. The tumor appears as a dominant mass in the thyroid gland and is often associated with local lymph node involvement. We describe our experience of primary malignant teratoma of the thyroid in two young women who were treated with aggressive chemotherapy and surgical intervention.

METHODS

Medical records of two patients treated between 1993 and 1995 were reviewed. Both patients were women (36 years old and 34 years old). The diagnosis of primary malignant teratoma of the thyroid was made on the basis of clinical, radiographic, and microscopic findings. Patients were treated with aggressive combination chemotherapy consisting of alternating regimens similar to those used for high-volume germ-cell tumor patients at the University of Texas M. D. Anderson Cancer Center.

RESULTS

One of the patients demonstrated a partial response to chemotherapy and underwent postchemotherapy surgery for removal of residual disease. The other patient had a complete response to chemotherapy. Both patients are alive and disease free for 32- and 26-plus months.

CONCLUSIONS

Primary malignant teratoma of the thyroid is sensitive to combination chemotherapy. It appears that the treatment strategy offered-aggressive induction chemotherapy with planned surgery for removal of residual disease, similar to that for patients with testicular tumors-has the potential to provide a durable, complete remission.