Studies on Nucleic Acid Reassociation Kinetics: Retarded Rate of Hybridization of RNA with Excess DNA

The rate of reaction of excess double-stranded bacteriophage phi X174 and plasmid RSF2124 DNA drivers with enzymatically synthesized asymmetric RNA tracers was measured. Other reactions were carried out with excess Escherichia coli DNA and E. coli RNA labeled in vivo. RNA and DNA fragment lengths were held approximately equal. For each case it was shown that in DNA excess the rate constant for RNA· DNA hybridization is 3- to 4.5-fold lower than that of the renaturation rate constant for the driver DNA. This retardation was also observed in pseudo-first-order hybridization reactions driven by excess strand-separated RSF2124 DNA. It was concluded that the rate constant for RNA· DNA hybridization depends partially on which species is in excess

Ovarian Hyperstimulation Syndrome: Current Views on Pathophysiology, Risk Factors, Prevention, and Management

Objective: To summarize current views on the pathophysiology, risk factors, prevention, clinical features, and management of Ovarian Hyperstimulation Syndrome (OHSS). Design: Literature review. Results: OHSS is a condition characterized by increased capillary permeability, and experimental evidence has identified a provocative link to pathologic vasoactive cytokine actions. Although the ultimate physiologic mechanism of OHSS is not yet known, there are well-known risk factors that must be considered during the administration of medications to treat infertility. Clinical features are consequences of third-spaced intravascular fluid, and OHSS may become life-threatening secondary to thromboembolism or compromised pulmonary or cardiovascular function. Cornerstones of prevention have historically included cycle cancellation, coasting, decreased dosing of human chorionic gonadotropin (hCG) trigger, use of an agonist trigger, and cryopreservation of all embryos. Newer methods of prevention include the administration of a dopamine agonist medication. Management options for OHSS include outpatient transvaginal paracentesis, outpatient transabdominal paracentesis, and inpatient hospitalization with or without paracentesis. Conclusions: OHSS continues to be a serious complication of assisted reproductive therapy (ART), with no universally agreed upon best method of prevention. Coasting and cryopreservation of all embryos are the most commonly used approaches in the literature, but cycle cancellation is the only method that can completely prevent the development of OHSS. Dopamine agonists are currently being investigated to both prevent and improve the clinical course in OHSS. Recent publications suggest that outpatient paracentesis both prevents the need for inpatient hospitalization and is a cost-effective strategy

Ovarian Hyperstimulation Syndrome: Current Views on Pathophysiology, Risk Factors, Prevention, and Management

OBJECTIVE: To summarize current views on the pathophysiology, risk factors, prevention, clinical features, and management of Ovarian Hyperstimulation Syndrome (OHSS). DESIGN: Literature review RESULTS: OHSS is a condition characterized by increased capillary permeability, and experimental evidence has identified a provocative link to pathologic vasoactive cytokine actions. Although the ultimate physiologic mechanism of OHSS is not yet known, there are well-known risk factors that must be considered during the administration of medications to treat infertility. Clinical features are consequences of third-spaced intravascular fluid, and OHSS may become life-threatening secondary to thromboembolism or compromised pulmonary or cardiovascular function. Cornerstones of prevention have historically included cycle cancellation, coasting, decreased dosing of human chorionic gonadotropin (hCG) trigger, use of an agonist trigger, and cryopreservation of all embryos. Newer methods of prevention include the administration of a dopamine agonist medication. Management options for OHSS include outpatient transvaginal paracentesis, outpatient transabdominal paracentesis, and inpatient hospitalization with or without paracentesis. CONCLUSIONS: OHSS continues to be a serious complication of assisted reproductive therapy (ART), with no universally agreed upon best method of prevention. Coasting and cryopreservation of all embryos are the most commonly used approaches in the literature, but cycle cancellation is the only method that can completely prevent the development of OHSS. Dopamine agonists are currently being investigated to both prevent and improve the clinical course in OHSS. Recent publications suggest that outpatient paracentesis both prevents the need for inpatient hospitalization and is a cost-effective strategy

Manuscript has been retracted

International Journal of Exercise Science 7(2) : 128-139, 2014. Manuscript has been retracted

A disrupted circumstellar torus inside eta Carinae's Homunculus Nebula

We present thermal infrared images of the bipolar nebula surrounding eta Carinae at six wavelengths from 4.8 to 24.5 microns. These were obtained with the MIRAC3 camera system at the Magellan Observatory. Our images reveal new intricate structure in the bright core of the nebula, allowing us to re-evaluate interpretations of morphology seen in images with lower resolution. Complex structures in the core might not arise from a pair of overlapping rings or a cool (110 K) and very massive dust torus, as has been suggested recently. Instead, it seems more likely that the arcs and compact knots comprise a warm (350 K) disrupted torus at the intersection of the larger polar lobes. Some of the arcs appear to break out of the inner core region, and may be associated with equatorial features seen in optical images. The torus could have been disrupted by a post-eruption stellar wind, or by ejecta from the Great Eruption itself if the torus existed before that event. Kinematic data are required to rule out either possibility.Comment: 8 pages, 3 figures (Fig. 1 in color); to appear in ApJ Letter