Identification of non-conventional small molecule degraders and stabilizers of squalene synthase.

Squalene synthase (SQS) is an essential enzyme in the mevalonate pathway, which controls cholesterol biosynthesis and homeostasis. Although catalytic inhibitors of SQS have been developed, none have been approved for therapeutic use so far. Herein we sought to develop SQS degraders using targeted protein degradation (TPD) to lower overall cellular cholesterol content. We found that KY02111, a small molecule ligand of SQS, selectively causes SQS to degrade in a proteasome-dependent manner. Unexpectedly, compounds based on the same scaffold linked to E3 ligase recruiting ligands led to SQS stabilization. Proteomic analysis found KY02111 to reduce only the levels of SQS, while lipidomic analysis determined that KY02111-induced degradation lowered cellular cholesteryl ester content. Stabilizers shielded SQS from its natural turnover without recruiting their matching E3 ligase or affecting enzymatic target activity. Our work shows that degradation of SQS is possible despite a challenging biological setting and provides the first chemical tools to degrade and stabilize SQS.

Identification of Dihydroorotate Dehydrogenase Inhibitors Using the Cell Painting Assay.

Profiling approaches have been increasingly employed for the characterization of disease-relevant phenotypes or compound perturbation as they provide a broad, unbiased view on impaired cellular states. We report that morphological profiling using the cell painting assay (CPA) can detect modulators of de novo pyrimidine biosynthesis and of dihydroorotate dehydrogenase (DHODH) in particular. The CPA can differentiate between impairment of pyrimidine and folate metabolism, which both affect cellular nucleotide pools. The identified morphological signature is shared by inhibitors of DHODH and the functionally tightly coupled complex III of the mitochondrial respiratory chain as well as by UMP synthase, which is downstream of DHODH. The CPA appears to be particularly suited for the detection of DHODH inhibitors at the site of their action in cells. As DHODH is a validated therapeutic target, the CPA will enable unbiased identification of DHODH inhibitors and inhibitors of de novo pyrimidine biosynthesis for biological research and drug discovery.

Periviable birth: executive summary of a Joint Workshop by the Eunice Kennedy Shriver National Institute of Child Health and Human Development, Society for Maternal-Fetal Medicine, American Academy of Pediatrics, and American College of Obstetricians and Gynecologists.

This is an executive summary of a workshop on the management and counseling issues of women anticipated to deliver at a periviable gestation (broadly defined as 20 0/7 through 25 6/7 weeks of gestation), and the treatment options for the newborn. Upon review of the available literature, the workshop panel noted that the rates of neonatal survival and neurodevelopmental disabilities among the survivors vary greatly across the periviable gestations and are significantly influenced by the obstetric and neonatal management practices (for example, antenatal steroid, tocolytic agents and antibiotic administration; cesarean birth; and local protocols for perinatal care, neonatal resuscitation and intensive care support). These are, in turn, influenced by the variations in local and regional definitions of limits of viability. Because of the complexities in making difficult management decisions, obstetric and neonatal teams should confer prior to meeting with the family, when feasible. Family counseling should be coordinated with the goal of creating mutual trust, respect and understanding, and should incorporate evidence-based counseling methods. Since clinical circumstances can change rapidly with increasing gestational age, counseling should include discussion of the benefits and risks of various maternal and neonatal interventions at the time of counseling. There should be a plan for follow-up counseling as clinical circumstances evolve. The panel proposed a research agenda and recommended developing educational curricula on the care and counseling of families facing the birth of a periviable infant.

Surgical resection of endometriosis after prior hysterectomy.

Twenty-seven patients who underwent laparotomy after a prior hysterectomy for endometriosis were studied. The mean interval from index surgery to repeat surgery was 7.8 years. Abdominal/pelvic pain was the most common presenting complaint, followed by the objective finding of a pelvic mass. Six patients were taking estrogen replacement therapy. Physical findings suggested a pelvic mass or nodularity in 15 patients. Extensive pelvic adhesions with dense involvement of the ovaries was common. Surgery in 2 patients was complicated by an enterotomy, with 4 patients requiring a bowel resection and anastomosis. Postoperatively, 5 patients developed fever, 3 a postoperative ileus, 1 a wound breakdown, and 1 a small bowel obstruction. The mean hospital stay was 5 days. We conclude that in patients who have undergone a hysterectomy as treatment for endometriosis, subsequent surgery to remove the ovaries involved with recurrent endometriosis carries considerable morbidity. In light of readily available estrogen replacement therapy, conservation of the ovaries in patients who are undergoing a hysterectomy for endometriosis should be applied with caution.

Immunoassays for quantifying choriogonadotropin compared for assay performance and clinical application.

We examined calibration and accuracy, precision, sensitivity, specificity, and "hook" effects for recently revised automated choriogonadotropin (hCG) immunoassay systems (Baxter-Dade Stratus II, Abbott IMx intact hCG and total beta hCG) and compared them with a widely used immunoradiometric assay (Hybritech). We estimated hCG in pregnant women, women with trophoblastic disease, nonpregnant young and menopausal women, normal men, and men with testicular tumors. We found clinically unimportant differences in calibration (all calibrated to the 3rd International Standard). Detection of hCG by all four assays was limited by their responses in serum from nonpregnant women and men. Precision within-run was best for the automated instruments, but all four assays had similar between-run precision. The Hybritech, Stratus, and IMx intact assays are specific for intact hCG. The IMx total beta assay quantifies both free beta subunit and beta subunit present in intact hCG. There is a clinically important hook effect in the Hybritech assay but not the Stratus or IMx assays (to 1.2 x 10(6) int. units/L). Results for pregnant women were similar by all four assays. We measured "hCG" to 8 int. units/L in menopausal women, which weakly correlated with concentrations of lutropin and follitropin and was, in part, explained by crossreactivity. There was no sample-probe carryover in either instrument. We found the IMx diluting module as well as results at the extremes of the IMx calibration curves (less than 10, 800-1200 int. units/L) unreliable but encountered no such problems with the Stratus system. Both automated systems involve batch analyzers with limited throughput but provide hCG concentration estimates much more quickly than the Hybritech assay can.

Vaginal birth after cesarean section: the impact of patient resistance to a trial of labor.

In spite of the relative safety and medical advantages of vaginal birth after cesarean section, the procedure continues to be underutilized in the private practice setting. To evaluate the hypothesis that resistance by the patient often precludes a trial of labor, an observational study was conducted of all women with a history of one prior cesarean section who were delivered in 1989 at Ochsner Foundation Hospital. The choices of 167 women and the judgments of their obstetricians were longitudinally recorded during the antepartum and intrapartum course. Patients routinely received the patient guide of the American College of Obstetricians and Gynecologists for vaginal birth after cesarean section. Ultimately, 50% of patients who were encouraged by their obstetrician toward vaginal birth after cesarean section opted for an elective repeat cesarean section without a trial of labor. Reasons for patient resistance are enumerated and potential future remedial proposals are discussed.

Nasal fractures in adults -a brief discussion of principles.

A discussion of the management of acute nasal fractures in adults is presented. Repair of the nasal injury should be postponed so the patient can be stabilized and totally evaluated while the surgeon plans and prepares to do the optimum nose operation. Two weeks or more may be allowed for this with a few stated exceptions. Acute nasal fractures are the misguided mobilization phase of a nasal reconstruction. This must be rectified and completed and the nose modifed and repaired in accordance with the principles of functional rhinologic surgery. Some remarks on the fallibility of X-ray diagnosis are included.