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Biomedical subjects

S Craigo

Publications and source records attributed to S Craigo.

4 recordsLinked to original sources
PubMed2002

Rupture of the renal pelvis associated with intravenous fluid bolus.

Previously reported cases of spontaneous rupture of the kidney or ureter reflect underlying renal pathology and have been reported both spontaneously and in relationship to delivery, but not in relation to other operative procedures. A 27-year-old woman at 19 weeks' gestation developed severe right flank pain in the operating room immediately prior to cerclage placement. Postoperative renal ultrasound examination and intravenous pyelogram performed to evaluate persistent flank pain demonstrated renal pelvis rupture. No other renal abnormality was present. We postulated that increased urine flow from the fluid bolus for the spinal anesthetic precipitated the rupture.

Adult↗
PubMed1993

A single point mutation (Phe340-->Leu340) of a conserved phenylalanine abolishes 4-[125I]iodo-(2,5-dimethoxy)phenylisopropylamine and [3H]mesulergine but not [3H]ketanserin binding to 5-hydroxytryptamine2 receptors.

The molecular processes by which agonists and antagonists bind to serotonin2 [5-hydroxytryptamine (5-HT2)] receptors are currently unknown. Three molecular models have proposed that conserved aromatic residues help to anchor the phenyl ring of 5-HT via stacking or pi-pi-type interactions with the 5-HT2 receptor. To test these models we made single point mutations (Phe339-->Leu339 and Phe340-->Leu340) of two aromatic residues that are conserved among all guanine nucleotide-binding protein-coupled 5-HT receptors and a single point mutation (Phe125-->Leu125) that exchanges a 5-HT2 for a 5-HT1c sequence. [3H]Mesulergine binding was abolished by Phe340-->Leu340 and unchanged with the Phe339-->Leu339 and Phe125-->Leu125 mutations, whereas [3H]ketanserin binding affinity was diminished by the Phe339-->Leu339 mutation and unchanged by Phe340-->Leu340 and Phe125-->Leu125. We also found that the affinities of three ergot derivatives (mesulergine, methysergide, and lisuride) were decreased by 88-1079-fold with only the Phe340-->Leu340 mutation. We also discovered that 4-[125I]iodo-2,5-(dimethoxy)phenylisopropylamine (DOI) binding was abolished in COS-7 cells expressing 5-HT2 (Phe340-->Leu340) receptors but maintained in cells expressing the Phe339-->Leu339 and Phe125-->Leu125 mutations. Additionally, the Ki values for several agonists and partial agonists (5-HT, DOI, m-chlorophenylpiperazine, trifluoromethylphenylpiperazine, bufotenine, and MK-212) were greatly diminished (26-14,000-fold decrease) only with the Phe340-->Leu340 receptor mutation. Finally, the Phe340-->Leu340 mutant receptors displayed an attenuated or abolished ability to augment phosphoinositide hydrolysis in COS-7 cells with four separate agonists (5-HT, MK-212, bufotenine, and quipazine). Taken together, these results are consistent with the idea that agonists and certain ergot derivatives anchor to 5-HT2 receptors, in part, via specific interactions with aromatic residue Phe340 located in transmembrane region VI.

Amino Acid Sequence↗
PubMed1992

Identification of receptor domains that modify ligand binding to 5-hydroxytryptamine2 and 5-hydroxytryptamine1c serotonin receptors.

Serotonin [5-hydroxytryptamine (5-HT)] receptors are distinguished pharmacologically by their characteristic affinities for agonists and antagonists. Two serotonin receptors, the 5-HT2 and 5-HT1c, share a number of pharmacologic and structural properties while differing in their affinities for certain agonists and antagonists. To identify regions of the 5-HT2 and 5-HT1c receptors important for specifying their unique pharmacology, we constructed six chimeric 5-HT2/5-HT1c receptors in which domains of each receptor were exchanged. The abilities of several drugs to inhibit [3H]mesulergine bound to the chimeric and parent receptors transiently expressed in COS-7 cells were then examined. For spiperone and haloperidol (both butyrophenones), chimeras that exchanged transmembrane (TM) domains I and II or TMs I-III had the greatest effects on binding affinity. The binding affinity of cinanserin (a cinnamanilide) was significantly changed in all the chimeras studied. In contrast, the binding of ketanserin (a 4-fluorobenzoylpiperidine) was strongly influenced by chimeras that exchanged TMs I-III (but not I and II) and by chimeras that exchanged intracellular loop 3 to TM VII. 5-HT binding affinity was greatly altered for chimeras that exchanged domains of intracellular loop 3 to TM VII, with minor effects being noted for chimeras that exchanged TMs I and II and I-III. The affinities of the nonselective drugs mesulergine, mianserin, and m-chlorophenylpiperazine were relatively unaffected when domains of the 5-HT2 and 5-HT1c receptors were exchanged. Taken together, these results imply that structurally diverse 5-HT2 antagonists utilize distinct regions of the 5-HT2 receptor for high affinity binding.

Base Sequence↗