Complex role of zinc in methamphetamine toxicity in vitro.

Methamphetamine is a drug of abuse that can induce oxidative stress and neurotoxicity to dopaminergic neurons. We have previously reported that oxidative stress promotes the liberation of intracellular Zn(2+) from metal-binding proteins, which, in turn, can initiate neuronal injurious signaling processes. Here, we report that methamphetamine mobilizes Zn(2+) in catecholaminergic rat pheochromocytoma (PC12) cells, as measured by an increase in Zn(2+)-regulated gene expression driven by the metal response element transcription factor-1. Moreover, methamphetamine-liberated Zn(2+) was responsible for a pronounced enhancement in voltage-dependent K(+) currents in these cells, a process that normally accompanies Zn(2+)-dependent cell injury. Overnight exposure to methamphetamine induced PC12 cell death. This toxicity could be prevented by the cell-permeant zinc chelator N,N,N', N'-tetrakis(2-pyridylmethyl)-ethylenediamine (TPEN), and by over-expression of the Zn(2+)-binding protein metallothionein 3 (MT3), but not by tricine, an extracellular Zn(2+) chelator. The toxicity of methamphetamine to PC12 cells was enhanced by the presence of co-cultured microglia. Remarkably, under these conditions, TPEN no longer protected but, in fact, dramatically exacerbated methamphetamine toxicity, tricine again being without effect. Over-expression of MT3 in PC12 cells did not mimic these toxicity-enhancing actions of TPEN, suggesting that the chelator affected microglial function. Interestingly, P2X receptor antagonists reversed the toxicity-enhancing effect of TPEN. As such, endogenous levels of intracellular Zn(2+) may normally interfere with the activation of P2X channels in microglia. We conclude that Zn(2+) plays a significant but complex role in modulating the cellular response of PC12 cells to methamphetamine exposure in both the absence and presence of microglia.

Effect of age on kainate-induced seizure severity and cell death.

While the onset and extent of epilepsy increases in the aged population, the reasons for this increased incidence remain unexplored. The present study used two inbred strains of mice (C57BL/6J and FVB/NJ) to address the genetic control of age-dependent neurodegeneration by building upon previous experiments that have identified phenotypic differences in susceptibility to hippocampal seizure-induced cell death. We determined if seizure induction and seizure-induced cell death are affected differentially in young adult, mature, and aged male C57BL/6J and FVB/NJ mice administered the excitotoxin, kainic acid. Dose response testing was performed in three to four groups of male mice from each strain. Following kainate injections, mice were scored for seizure activity and brains from mice in each age group were processed for light microscopic histopathologic evaluation 7 days following kainate administration to evaluate the severity of seizure-induced brain damage. Irrespective of the dose of kainate administered or the age group examined, resistant strains of mice (C57BL/6J) continued to be resistant to seizure-induced cell death. In contrast, aged animals of the FVB/NJ strain were more vulnerable to the induction of behavioral seizures and associated neuropathology after systemic injection of kainic acid than young or middle-aged mice. Results from these studies suggest that the age-related increased susceptibility to the neurotoxic effects of seizure induction and seizure-induced injury is regulated in a strain-dependent manner, similar to previous observations in young adult mice.

Antisocial personality, substance abuse, and exposure to parental violence in males referred for domestic violence.

This study investigated whether childhood disruptive behavior (hyperactivity, oppositional-defiance, conduct problems) plus adult psychopathic adjustment are associated with domestic violence. Adult males (n = 66) in diversion programs completed the Wender Utah Rating Scale (WURS), MMPI Psychopathic Deviate scale (PD), Conflict Tactics Scales representing themselves and their parents, and substance use measures. Substance use and lifespan antisocial personality (measured by high WURS and PD scores) were robust predictors of verbal and moderate physical domestic abuse. Violence in the family of origin was associated with abuse when tested alone, but failed to exhibit unique association with abuse when other predictors were taken into account. The possibility that antisocial batterers respond to contingencies by moderating physical harm, while persisting at psychological harm, is discussed.

Skin cancer of the head and neck with clinical perineural invasion.

PURPOSE: To review treatment and outcomes in 62 patients with clinical and/or gross evidence of perineural invasion from skin cancer of the head and neck. METHODS AND MATERIALS: Sixty-two patients received radiotherapy at the University of Florida as part or all of their treatment between January 1965 and April 1995. All patients had clinical signs and symptoms of perineural involvement and/or documentation of tumor extending to grossly involve nerve(s). Twenty-one patients underwent therapy for previously untreated lesions, including 12 who received radiotherapy alone and nine who had surgery with postoperative radiotherapy. Forty-one patients underwent therapy for recurrent lesions, including 18 treated with radiotherapy alone and 23 who received preoperative or postoperative radiotherapy. RESULTS: Factors on multivariate analysis that predicted local control included patient age, previously untreated vs. recurrent lesions, presence of clinical symptoms, and extent of radiotherapy fields. Recurrence patterns were predominantly local; 26 of 31 patients (84%) who developed local recurrence after treatment had recurrent cancer limited to the primary site. CONCLUSIONS: Many patients with skin cancer and symptomatic perineural invasion have disease that is incompletely resectable. Approximately half these patients will be cured with aggressive irradiation alone or combined with surgery. Age, prior treatment, and clinical symptoms influence the likelihood of cure.

Predictors of success of methotrexate treatment in women with tubal ectopic pregnancies.

BACKGROUND: The use of methotrexate for the treatment of women with tubal ectopic pregnancies is now common practice. However, the clinical and hormonal determinants of the success of this treatment are not known. METHODS: We studied 350 women with tubal ectopic pregnancies who were treated with methotrexate intramuscularly according to a single-dose protocol. Pretreatment serum concentrations of human chorionic gonadotropin and progesterone, the size and volume of the gestational mass, fetal cardiac activity, and the presence of fluid (presumably blood) in the peritoneal cavity were correlated with the efficacy of therapy, as defined by resolution of the ectopic pregnancy without the need for surgical intervention. RESULTS: There was no relation between the women's age or parity, the size or volume of the conceptus, or the presence of fluid in the peritoneal cavity and the efficacy of treatment. Among the 320 women in whom treatment was successful (91 percent), the mean (+/-SD) serum chorionic gonadotropin and progesterone concentrations were 4019+/-6362 mIU per milliliter and 6.9+/-6.7 ng per milliliter (21.9+/-21.3 nmol per liter), respectively, as compared with 13,420+/-16,590 mIU per milliliter and 10.2+/-5.5 ng per milliliter (32.4+/-17.5 nmol per liter) (P<0.001 and P=0.02) in the 30 women in whom treatment was not successful. Fetal cardiac activity was present in 12 percent of the successfully treated cases and 30 percent of those in which treatment was not successful (P=0.01). Regression analysis revealed the pretreatment serum chorionic gonadotropin concentration to be the only factor that contributed to the failure rate. CONCLUSIONS: Among women with tubal ectopic pregnancies, a high serum chorionic gonadotropin concentration is the most important factor associated with failure of treatment with a single-dose methotrexate protocol.

Retrovirus DNA termini bound by integrase communicate in trans for full-site integration in vitro.

Integration of linear retrovirus DNA involves the concerted insertion of the viral termini (full-site integration) into the host chromosome. We investigated the interactions that occur between long terminal repeat (LTR) termini bound by avian retrovirus integrase (IN) for full-site integration in vitro. Wild-type (wt) or mutant LTR donors that possess gain-of-function ("G") or loss-of-function ("L") for full-site integration activity were used. G LTR termini are characterized as having significantly higher strand transfer activity than the wt and the L LTR termini. L LTR mutations are classified as partially or extremely defective for strand transfer activity. The L mutations were further classified by their ability to either permit or block the assembly of G or wt LTR termini into nucleoprotein complexes capable of full-site strand transfer. We demonstrated that avian myeloblastosis virus IN bound to G LTR termini increased the incorporation of partially defective L LTR termini into nucleoprotein complexes that were capable of full-site integration. The observed full-site integration activity of these assembled nucleoprotein complexes appeared to be influenced by each individual IN-LTR complex in trans. In contrast, extremely defective L LTR termini exhibited the ability to effectively block the assembly of wt LTR termini into nucleoprotein complexes capable of full-site strand transfer. Data from nonspecific DNA competition experiments suggested that IN had an apparent higher affinity for G LTR donor termini than for partially defective L LTR donor termini as measured by full-site integration activity. However, assembled nucleoprotein complexes containing either two G or two L LTR donors were stable, having a similar half-life of approximately 2 h on ice. The results suggest that LTR termini bound by IN exhibit an allosteric effect to modulate full-site integration in vitro. Similar regulatory controls also appear to exist in vivo between the wt U3 and wt U5 LTR termini in retroviruses as well as purified retrovirus preintegration complexes that promoted full-site integration in vitro.

Skin cancer of the head and neck with incidental microscopic perineural invasion.

PURPOSE: To address outcomes in clinically asymptomatic patients in whom the unexpected finding of microscopic perineural invasion is noted at the time of surgery. METHODS AND MATERIALS: The 35 patients included in this study had skin cancers of the head and neck treated with curative intent between January 1965 and April 1995 at the University of Florida. All patients were without clinical or radiographic evidence of perineural invasion but, at the time of biopsy or surgical excision, had the incidental finding of microscopic perineural invasion. Definitive therapy consisted of radiotherapy alone after lesion biopsy (3 patients) or surgical excision preceded (2 patients) or followed (30 patients) by radiotherapy. All patients had follow-up for at least 1 year, 13 patients (37%) had follow-up for at least 5 years. RESULTS: The 5-year local control rate was 78%. The 5-year local control rate for the few patients treated with radiotherapy alone was statistically similar to that for patients treated with surgery and radiotherapy (100% vs. 77%, p = 0.4). Multivariate analysis for factors affecting local control included sex, histology, age, treatment group, clinical T stage, initial histologic differentiation, and previously untreated vs. recurrent tumors, none of which was found to be significant. CONCLUSIONS: Both surgery plus radiotherapy and radiotherapy alone provide a relatively high rate of local control for patients with incidentally discovered perineural invasion secondary to skin cancer.

Respiratory failure. After the intensive care unit.

RF is a unique situation. It is specific in diagnosis and yet, at the same time, broad in concept. It can be acutely life threatening or chronic in presentation and need for intervention. Patients are cared for in ICUs, medical-surgical floors, and nursing homes as well as at home. When RF is a complicating condition of an already hospitalized patient, the road to recovery may be long and complicated. It is important that the health care team provides education and counseling so that the patient and family can cope with the changing events and the potentially long road to recovery. Outcome data from all the sites of care are currently lacking for a comparative analysis of the most effective site. All the sites of care discussed in this article are cost-effective alternatives to the ICU, but there is a lack of standards and evidence of measurable outcomes such as the quality and cost relationship. Outcome data are needed to document the cost of care and the relationship of that cost to specific outcomes such as final discharge disposition, survival, complications, and quality of life. Health care provides have a much clearer image of the care that can be provided in the multiple sites available. Unfortunately, patients and families do not have that same level of understanding. For many patients and families, regardless of what the facility is called, it is not the acute hospital, and that is where they wish to remain until discharge home. Clarification and standardization are needed regarding the terminology used to describe the various sites of care. It is important that integrated health care institutions provide education and counseling to patients and families regarding the continuum of care and the many alternatives along that path.

Aspiration and microscopy in the diagnosis of ectopic pregnancy.

OBJECTIVE: To compare Karman cannula aspiration followed by dissecting microscopy with suction curettage and permanent histology in obtaining and identifying chorionic villi. METHODS: Karman cannula aspiration was performed before standard curettage for failed intrauterine pregnancies (N=22) or possible ectopic gestation (N=24). Dissection microscopy for chorionic villi was performed on aspirates before submission for permanent histology. Sensitivity, specificity, positive and negative predictive value of each method in obtaining and identifying villi was determined. RESULTS: Overall, all methods were only moderately sensitive in detecting chorionic villi (50-76%). If failed intrauterine pregnancies were excluded, all methods had poor sensitivity (25-64%). However, if villi were detected, the positive predictive value of all methods was high (> 80%). CONCLUSIONS: Karman cannula aspiration followed by dissecting microscope examination or permanent histology may offer an alternative to traditional curettage in the diagnosis of ectopic gestations. A larger trial to validate these findings seems justified.

Purification of recombinant Rous sarcoma virus integrase possessing physical and catalytic properties similar to virion-derived integrase.

Recombinant Rous sarcoma virus integrase cloned from the Prague A (PrA) virus strain was expressed in Escherichia coli. Here we report the detailed purification procedure resulting in an apparently homogeneous integrase. Recombinant PrA integrase was compared at both the protein structural and the catalytic levels to avian myeloblastosis virus integrase purified from virions. Both proteins exist minimally in a dimeric state at low nanomolar concentrations as analyzed by glycerol gradient sedimentation and protein crosslinking studies. Likewise, both proteins have similar specific activities for full-site (concerted integration reaction) and half-site strand transfer activities using linear 480-bp retrovirus-like donor substrates that contain wild-type or mutant termini. They respond similarly to high NaCl concentrations ( approximately 350 mM) as well as aprotic solvents for efficient full-site strand transfer. The data suggest that recombinant integrase proteins with physical and catalytic properties similar to the virion counterpart can be purified using these techniques and will faithfully and efficiently promote the full-site integration reaction in vitro.

Analysis of three hundred fifteen ectopic pregnancies treated with single-dose methotrexate.

OBJECTIVES: The objective of this study was to review the largest single series of ectopic pregnancies treated with single-dose methotrexate reported to date. STUDY DESIGN: A review of 315 patients with unruptured ectopic pregnancies treated with single-dose methotrexate 50 mg/m2 from March 21, 1990, to March 1, 1997, was performed. RESULTS: Overall 287 patients were successfully treated with methotrexate for a success rate of 90.1%. Six patients electively withdrew and requested surgery within 1 week of starting therapy. Excluding withdrawals the overall success rate was 92.9%. Ten patients with an ectopic pregnancy > 3.5 cm but < or = 4 cm in size were treated for a 90% success rate. Forty-four patients with positive ectopic cardiac activity were treated with an 87.5% success rate. CONCLUSIONS: This large series indicates that single-dose intramuscular methotrexate for treatment of ectopic pregnancy is associated with an excellent overall success rate.

Health status utility assessment by standard gamble: a comparison of the probability equivalence and the lottery equivalence approaches.

PURPOSE: Utility values obtained with the standard gamble (SG) method using the probability equivalence approach (PE) have a reported bias due to the "certainty effect." This effect causes individuals to overvalue a positive outcome when it occurs under certainty. Researchers in the decision sciences have proposed an alternative, "lottery equivalence" (LE) approach, using paired gambles, to eliminate this bias. The major objective of the current study was to investigate the certainty effect in health status utility measures and to test our hypothesis that the certainty effect would act in a reverse direction for negatively valued outcomes. METHODS: Fifty-four subjects completed the study by assessing preferences for three health states by rating scale and then by SG using PE as well as LE approaches with assessment lotteries of 0.5 and 0.75. RESULTS: The results from 41 useable responses point towards possible existence of the certainty effect in health in the hypothesized direction: utility values obtained with the PE were significantly lower than with the LEs. There was no significant difference between the LE values indicating elimination of the bias. CONCLUSIONS: The results have important implications since the SG using PE is thought be the "gold standard" in health status utility measurements.

Hydroxamate-based inhibitors of low affinity IgE receptor (CD23) processing.

A series of hydroxamic acids related to the non-selective matrix metalloprotease inhibitor Batimastat is described, which inhibits the proteolytic cleavage of the low affinity IgE receptor from cell membrane preparations. Limited SAR studies suggest that the structural requirements for effective inhibition are distinct from those required for the inhibition of collagenase.

Selective inhibition of low affinity IgE receptor (CD23) processing.

A series of hydroxamic acids related to the non-selective matrix metalloproteinase inhibitor Batimastat has been prepared, some members of which are potent inhibitors of the processing of the low affinity IgE receptor (CD 23). Increased activity is obtained by appropriate substitution at the alpha-position, whilst selectivity is gained by use of a P1' benzyl group in conjunction with a C-terminal primary amide.

Cytosolic 85-kDa phospholipase A2-mediated release of arachidonic acid is critical for proliferation of vascular smooth muscle cells.

Recent evidence suggests that arachidonic acid (AA) may be involved in regulating cellular proliferation. The predominant mechanism of AA release from cellular phospholipids is via phospholipase A2 (PLA2) hydrolysis. The purpose of this study was to examine the roles of the distinct 14-kDa and 85-kDa PLA2 enzymes in human coronary artery vascular smooth muscle cell (hCAVSMC) proliferation. Cultured hCAVSMCs proliferate in the presence of growth medium with a typical doubling time of 30-40 h, grow at a slower proliferative rate upon reaching confluency (day 8), and eventually undergo contact inhibition of growth (day 10). Neither Type II 14-kDa PLA2 activity nor mass changed over a 10-day culture period. In contrast, 85-kDa PLA2 protein activity and mRNA decreased as time in culture progressed. This reduction in 85-kDa PLA2 correlated with reductions in DNA synthesis and suggested a possible association between 85-kDa PLA2 and proliferation. To directly evaluate the role of the 85-kDa PLA2 in proliferation we examined the effects of an 85-kDa PLA2 inhibitor (AACOCF3) and 85-kDa PLA2 antisense oligonucleotides on proliferation. Both reagents dose dependently inhibited proliferation, whereas a 14-kDa PLA2 inhibitor (SB203347), a calcium-independent PLA2 inhibitor (HELSS), an 85-kDa sense oligonucleotide, and a nonrelevant scrambled control oligonucleotide had no effect. The mechanism by which 85-kDa PLA2 influences cellular proliferation remains unclear. Inhibition of 85-kDa PLA2 activity produced neither phase-specific cell cycle arrest nor apoptosis (fluorescence-activated cell sorter analysis). Addition of AA (20 mu M) attenuated the effects of both AACOCF3 and 85-kDa antisense oligonucleotides implicating AA as a key mediator in cellular proliferation. However, although prostaglandin E2 (PGE2) was present in the culture medium, it peaked early (day 3) in culture, and indomethacin had no effect on cellular proliferation indicating that hCAVSMC proliferation was not mediated through PGE2. These data provide the first direct evidence that PLA2 is involved in control of VSMC proliferation and indicate that 85-kDa PLA2-mediated liberation of AA is critical for cellular proliferation.

Radiotherapy for pituitary adenoma: long-term outcome and sequelae.

PURPOSE: To review outcome and treatment sequelae in patients treated with external beam radiotherapy for pituitary adenomas. METHODS AND MATERIALS: One hundred forty-one patients with pituitary adenomas received radiotherapy at the University of Florida and had 2-year minimum potential follow-up. One hundred twenty-one had newly diagnosed adenomas, and 20 had recurrent tumors. Newly diagnosed tumors were treated with surgery and radiotherapy (n = 98) or radiotherapy alone (n = 23). Patients with recurrent tumors received salvage treatment with surgery and radiotherapy (n = 10) or radiotherapy alone (n = 10). The impact of age, sex, presenting symptoms, tumor extent, surgery type, degree of resection, hormonal activity, primary or salvage therapy, and radiotherapy dose on tumor control was analyzed. Tumor control is defined by the absence of radiographic progression and stable or decreased hormone level (in hormonally active tumors) after treatment. Effect of therapy on vision, hormonal function, neurocognitive function, life satisfaction, and affective symptoms were examined. A Likert categorical scale survey was used for assessment of neurocognitive, life satisfaction, and affective symptom status. Survey results from the radiotherapy patients were compared with a control group treated with transsphenoidal surgery alone. Multivariate analysis used the forward step-wise sequence of chi squares for the log rank test. RESULTS: At 10 years, tumor control for the surgery and radiotherapy group (S + RT) was 95% and not statistically different (p = 0.58) than for patients treated with radiotherapy alone (RT) (90%). Patients with prolactin- and ACTH-secreting tumors had significantly worse tumor control, as did patients treated for recurrent tumors. Multivariate analysis for tumor control revealed that only young age was predictive of worse outcome (p = 0.0354). Visual function was either unaffected or improved in most patients, although four patients developed visual loss due to treatment. Hormonal function was affected adversely in 46 of the 93 patients for whom detailed hormonal information was available. Neurocognitive function evaluation revealed that patients in the S + RT group were more likely (p = 0.005) to report difficulty with memory than those in the RT-alone or S-alone groups. No significant difference in life satisfaction or affective symptoms was evident. CONCLUSIONS: Pituitary adenomas are well controlled by external beam radiotherapy, either alone or in combination with surgery. Visual symptoms often improve after treatment. Hormonal sequelae require medical intervention in many patients. Neurocognitive sequelae may be different among treatment groups.

Avian retrovirus U3 and U5 DNA inverted repeats. Role Of nonsymmetrical nucleotides in promoting full-site integration by purified virion and bacterial recombinant integrases.

The U3 and U5 termini of linear retrovirus DNA contain imperfect inverted repeats that are necessary for the concerted insertion of the termini into the host chromosome by viral integrase. Avian myeloblastosis virus integrase can efficiently insert the termini of retrovirus-like DNA donor substrates (480 base pairs) by a concerted mechanism (full-site reaction) into circular target DNA in vitro. The specific activities of virion-derived avian myeloblastosis virus integrase and bacterial recombinant Rous sarcoma virus (Prague A strain) integrase (approximately 50 nM or less) appear similar upon catalyzing the full-site reaction with 3'-OH recessed wild type or mutant donor substrates. We examined the role of the three nonsymmetrical nucleotides located at the 5th, 8th, and 12th positions in the U3 and U5 15-base pair inverted repeats for their ability to modify the full-site and simultaneously, the half-site strand transfer reactions. Our data suggest that the nucleotide at the 5th position appears to be responsible for the 3-5-fold preference for wild type U3 ends over wild type U5 ends by integrase for concerted integration. Additional mutations at the 5th or 6th position, or both, of U3 or U5 termini significantly increased (approximately 3 fold) the full-site reactions of mutant donors over wild type donors.

IgE secretion is attenuated by an inhibitor of proteolytic processing of CD23 (Fc epsilonRII).

CD23, the low-affinity IgE receptor, is up-regulated on interleukin (IL)-4-stimulated B cells and monocytes, with a concomitant increase in the release of soluble fragments of CD23 (sCD23) into the medium by proteolytic processing of the surface-bound intact CD23. The effect of inhibition of the processing of CD23 on IgE production in human and mouse cells and in a mouse model in vivo was evaluated. CD23 processing to sCD23 from RPMI 8866 (a human Epstein-Barr virus-transformed B cell line) cell membranes was inhibited by a broad-spectrum matrix-metalloprotease inhibitor, batimastat, with an IC50 of 0.15 microM. Batimastat also inhibited CD23 processing in whole RPMI 8866 cells as well as in IL-4-stimulated purified human monocytes with similar IC50. Batimastat inhibited IgE production from IL-4/anti-CD40-stimulated human tonsil B cells as well as mouse splenic B cells in a manner consistent with inhibition of CD23 processing. Release of soluble fragments of CD23 in the cell supernatants of tonsil B cells was inhibited over the concentration range of 1-10 microM batimastat and intact cell surface CD23 was increased on mouse splenic B cells in the presence of these concentrations of batimastat. IgE production of IL-4-stimulated human peripheral blood mononuclear cells was also blocked by 1-10 microM batimastat, again with comparable inhibition of sCD23 release over the same concentration range. Finally, in a mouse model of IgE production, batimastat inhibited IgE production in response to ovalbumin challenge as determined by serum IgE levels. Taken together, the data support a role of CD23 in IgE production and point to CD23 processing to sCD23 as a therapeutically relevant control point in the regulation of IgE synthesis.

Single serum progesterone as a screen for ectopic pregnancy: exchanging specificity and sensitivity to obtain optimal test performance.

OBJECTIVE: To investigate the diagnostic accuracy of screening serum P in diagnosis of ectopic pregnancy (EP) and to identify a cutoff value that provides the best compromise between test sensitivity and specificity. DESIGN: Retrospective analysis. SETTING: University hospital. INTERVENTIONS: Observation only. PATIENTS: First trimester pregnant women at risk for EP. MAIN OUTCOME MEASURE: Single P measurements were obtained from 3,674 pregnancies with outcomes defined as EP, viable intrauterine pregnancy (IUP), and spontaneous abortion (SAB). Diagnostic accuracy of the test was analyzed by generating receiver operating characteristic (ROC) curves, which quantify the ability of the test to distinguish EP and SAB from IUP. RESULTS: Diagnostic accuracy for EP versus IUP was 88.7% +/- 0.1% (mean +/- SEM); for SAB versus IUP, 93.8% +/- 0.4%; and for SAB + EP versus IUP, 92.8% +/- 0.4%. Diagnostic accuracy for SAB versus EP was only 39.4% +/- 0.2%. In the interval of 15.0 to 19.9 ng/mL (47.7 to 63.3 nmol/L), P missed 5.3% of the EPs and incorrectly included 84.3% of the viable IUPs; in the interval of 20.0 to 24.9 ng/mL (63.6 to 79.2 nmol/L), sensitivity improved in that only 3.5% of the EPs were missed but 88.8% of viable IUPs were included incorrectly. A cutoff value of > or = 17.5 ng/mL (55.7 nmol/L), the median point of the 15.0 to 19.9 ng/mL (47.7 to 63.3 nmol/L) interval, missed only 35 of 423 (8.3%) total EPs in the study. CONCLUSION: Analysis of ROC curves demonstrates that single serum P has high diagnostic accuracy for differentiating accidents of pregnancy (SAB and EP) from viable IUP, both individually (SAB versus IUP and EP versus IUP) and collectively (SAB + EP versus IUP); it cannot efficiently discriminate SAB versus EP. We conclude that for P > or = 17.5 ng/mL (55.7 nmol/L), patients thought to be at risk for EP may be followed reasonably without ultrasound or further invasive diagnostic studies.