The coral-derived natural products eleutherobin and sarcodictyins A and B: effects on the assembly of purified tubulin with and without microtubule-associated proteins and binding at the polymer taxoid site.

We examined interactions with purified tubulin of synthetic sarcodictyins A and B and eleutherobin (coral-derived antimitotic agents) and of compound 1, an analogue of sarcodictyin A methylated at the C-3 oxygen atom (i.e., the methyl ketal analogue of sarcodictyin A and thus structurally similar to eleutherobin but lacking the C-3 sugar moiety).

Purification, characterization, and drug susceptibility of tubulin from Leishmania.

Past work suggests that tubulin from kinetoplastid parasites may present an excellent drug target. To explore this possibility, tubulin was purified on a milligram scale from Leishmania mexicana amazonensis promastigotes by sonication, DEAE-Sepharose chromatography, and one cycle of assembly-disassembly. Purified leishmanial tubulin is recognized by commercially available anti-tubulin antibodies and displays concentration dependent assembly in vitro.

Improving searching skills and evidence retrieval.

Objective: To evaluate the effect of a three-hour training session in formulating questions and searching databases.

Design: A randomised controlled trial and before and after study, with blinded outcome assessment.

Setting: Oxford University Medical School, first clinical year.

Applying the results of trials and systematic reviews to individual patients.

Your patient is a 60-year-old hypertensive, alcoholic woman whose symptomless atrial fibrillation was first documented 3 months ago. An echocardiogram shows an enlarged left atrium, rendering successful cardioversion unlikely. She tells you that both of her parents had severe strokes that made the last years of their lives horrible, and she is terrified of having a stroke.

Benefit of carotid endarterectomy in patients with symptomatic moderate or severe stenosis. North American Symptomatic Carotid Endarterectomy Trial Collaborators.

Background: Previous studies have shown that carotid endarterectomy in patients with symptomatic severe carotid stenosis (defined as stenosis of 70 to 99 percent of the luminal diameter) is beneficial up to two years after the procedure. In this clinical trial, we assessed the benefit of carotid endarterectomy in patients with symptomatic moderate stenosis, defined as stenosis of less than 70 percent. We also studied the durability of the benefit of endarterectomy in patients with severe stenosis over eight years of follow-up.

Finding and applying evidence during clinical rounds: the "evidence cart".

Context: Physicians need easy access to evidence for clinical decisions while they care for patients but, to our knowledge, no investigators have assessed use of evidence during rounds with house staff.

Objective: To determine if it was feasible to find and apply evidence during clinical rounds, using an "evidence cart" that contains multiple sources of evidence and the means for projecting and printing them.

Design: Descriptive feasibility study of use of evidence during 1 month (April 1997) and anonymous questionnaire (May 1997).

Natural osmolyte trimethylamine N-oxide stimulates tubulin polymerization and reverses urea inhibition.

The natural osmolyte trimethylamine N-oxide (TMAO) is one of the methylamine compounds often accumulated by diverse organisms in response to osmotic stress and/or to compensate for the deleterious effects of urea. Tubulin polymerization is promoted by TMAO. At 1 M TMAO, tubulin polymers are produced with properties expected of normal steady-state microtubules (MT): polymerization is reversed by exposure to cold or the antimitotic drug podophyllotoxin, a critical concentration for polymerization at 30 degrees C of 1.

Paclitaxel-resistant human ovarian cancer cells have mutant beta-tubulins that exhibit impaired paclitaxel-driven polymerization.

Acquired resistance to paclitaxel can be mediated by P-glycoprotein or by alterations involving tubulin. We report two paclitaxel-resistant sublines derived from 1A9 human ovarian carcinoma cells. Single-step paclitaxel selection with verapamil yielded two clones that are resistant to paclitaxel and collaterally sensitive to vinblastine.