Biomedical subjects

Ali Asadi

Publications and source records attributed to Ali Asadi.

3 recordsLinked to original sources

PubMed2007

Janus-AT bases: synthesis, self-assembly, and solid state structures.

The high yielding synthesis of heterocycles with defined H-bond accepting and donating capabilities provides for the design of self-assembling structures and specific recognition of biological targets. Herein we report the syntheses and solid-state structures of three self-complementary uracil/thymine derivatives where each presents the standard ADA face inherently complementary to adenine and a synthetically appended DAD face complementary to uracil/thymine. These heterocycles, which have never before been reported or characterized, represent diaminopurine-uracil/thymine hybrids that, in two of the three cases, relate to previously reported heterocyclic hybrids of G and C. All three heterocycles crystallized to afford the first X-ray crystal structures of self-complementary heterocycles capable of ADA-DAD pairing. The potential use in DNA and RNA recognition are briefly discussed.

Adenine↗

PubMed2006

The pancreatic beta cell is a key site for mediating the effects of leptin on glucose homeostasis.

The hormone leptin plays a crucial role in maintenance of body weight and glucose homeostasis. This occurs through central and peripheral pathways, including regulation of insulin secretion by pancreatic beta cells. To study this further in mice, we disrupted the signaling domain of the leptin receptor gene in beta cells and hypothalamus. These mice develop obesity, fasting hyperinsulinemia, impaired glucose-stimulated insulin release, and glucose intolerance, similar to leptin receptor null mice. However, whereas complete loss of leptin function causes increased food intake, this tissue-specific attenuation of leptin signaling does not alter food intake or satiety responses to leptin. Moreover, unlike other obese models, these mice have reduced fasting blood glucose. These results indicate that leptin regulation of glucose homeostasis extends beyond insulin sensitivity to influence beta cell function, independent of pathways controlling food intake. These data suggest that defects in this adipoinsular axis could contribute to diabetes associated with obesity.

Animals↗

PubMed2005

Neonatal gastrointestinal stromal tumor. Report of a case and review of literature.

Gastrointestinal stromal tumor (GIST) is very rare in infancy. Most of the reported cases in the literature are in adults; some are in children but there are a few reported cases in the literature. The present case is a 6-day-old female neonate presenting with lethargy, poor feeding, constipation, abdominal distention, and rectal bleeding. She was operated on with the impression of intestinal obstruction, and right hemicolectomy was performed on her. Surgical specimen showed a well-defined and round 3-cm mass in the cecal area. Diagnosis was made by histologic and immunohistochemical studies which showed a GIST. The tumor showed positive vimentin and c-kit but negative for all other markers (desmin, actin, S100, NSE, and CD-34). So the case was an undifferentiated GIST. After 1 year of follow-up the patient was completely normal.

Biomarkers, Tumor↗