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Background Context Spinal osteoid osteomas are benign primary tumors arising predominantly from the posterior column of the spine. These "osteoblastic" lesions have traditionally been treated with intralesional excision. Purpose The purpose of the present study was to review the treatment and local recurrence rates for symptomatic spinal osteoid osteomas. Study Design/Setting Multicenter ambispective cross-sectional observational cohort study. Patient Sample During the study period, a total of 84 patients (65 males, 19 females) were diagnosed with a spinal osteoid osteoma and received surgical treatment. The mean age at surgery was 21.8 ± 9.0 years (range: 6.7–52.4 years) and the mean follow-up was 2.7 years (13 days–14.5 years). Outcome Measures Local recurrence, perioperative morbidity, and cross-sectional survival. Methods Using the AOSpine Knowledge Forum Tumor multicenter ambispective database, surgically treated osteoid osteoma cases were identified. Patient demographic, clinical and diagnostic, treatment, local recurrence, perioperative morbidity, and cross-sectional survival data were collected and retrieved. Descriptive statistics were summarized using mean/standard deviation or frequency/percentage. Results In our study, most of the tumors were localized in the mobile spine (81 of 84 [96%]); all patients reported pain as a symptom. According to the postoperative assessment, 10 (12%) patients received an en bloc resection with marginal or wide margins, whereas two (2%) patients received en bloc resections with intralesional margins, 69 (82%) patients were treated by piecemeal "intralesional" resection, and three (4%) patients were not assessed. A total of six patients (7%) experienced a local recurrence, all of which occurred in patients who had received an intralesional resection. Conclusions Benign bone-forming tumors of the spine are uncommon. Most patients in our series underwent a piecemeal resection with intralesional margins. This remains safe with a low local recurrence rate. En bloc excision may provide more chance of complete excision of the nidus but is not mandatory. The importance of complete excision of the nidus cannot be overemphasized.

Study design Multicenter, ambispective observational study. Objective To quantify local recurrence and mortality rates after surgical treatment of symptomatic spinal hemangiomas and identify prognostic variables for local disease control. Summary of background data Spinal hemangiomas are the most common primary tumors of the spine and are generally benign and usually asymptomatic. Because of the rarity of symptomatic spinal hemangiomas, optimal surgical treatment remains unclear. Methods AOSpine Knowledge Forum Tumor Investigators created a multicenter database of primary spinal tumors including demographics, presentation, diagnosis, treatment, survival, and recurrence data. Tumors were classified according to Enneking and Weinstein-Boriani-Biagini. Descriptive statistics were summarized and time to mortality and recurrence was determined. Results Between 1996 and 2012, 68 patients (mean age = 51 yr, SD = 16) underwent surgical treatment of a spinal hemangioma. Epidural disease was present in 55% of patients (n = 33). Pain and neurological compromise were presenting symptoms in 82% (n = 54) and 37% (n = 24) of patients, respectively. Preoperative embolization was performed in 35% of patients (n = 23), 10% (n = 7) had adjuvant radiotherapy, and 81% (n = 55) underwent posterior-alone surgery. The local recurrence rate was 3% (n = 2). Mortality secondary to spinal hemangioma was not observed (mean follow-up = 3.9 yr, SD = 3.8). Conclusion This is the largest multicenter surgical cohort of spinal hemangiomas. Symptomatic spinal hemangiomas are a benign tumor despite frequently presenting with epidural disease and neurological compromise. Thus, formal en bloc resection is not required, and excellent rates of local control and long-term survival can result from aggressive intralesional resection during index surgery. Level of evidence 3.

Object The National Institutes of Health recommends strategies to obtain evidence for the treatment of rare conditions such as primary tumors of the spine (PTSs). These tumors have a low incidence and are pathologically heterogeneous, and treatment approaches are diverse. Appropriate evidence-based care is imperative. Failure to follow validated oncological principles may lead to unnecessary mortality and profound morbidity. This paper outlines a scientific model that provides significant evidence guiding the treatment of PTSs. Methods A four-stage approach was used: 1) planning: data from large-volume centers were reviewed to provide insight; 2) recruitment: centers were enrolled and provided the necessary infrastructure; 3) retrospective stage: existing medical records were reviewed and completed with survival data; and 4) prospective stage: prospective data collection has been implemented. The AOSpine Knowledge Forum Tumor designed six modules: demographic, clinical, diagnostic, therapeutic, local recurrence, survival, and perioperative morbidity data fields and provided funding. Results It took 18 months to implement Stages 1–3, while Stage 4 is ongoing. A total of 1495 tumor cases were captured and diagnosed as one of 18 PTS histotypes. In addition, a PTS biobank network has been created to link clinical data with tumor pathology and molecular analysis. Conclusions This scientific model has not only aggregated a large amount of PTS data, but has also established an international collaborative network of spine oncology centers. Access to large volumes of data will generate further research to guide and enhance PTS clinical management. This model could be applied to other rare neoplastic conditions. Clinical trial registration no.: NCT01643174 (ClinicalTrials.gov).

Study design An ambispective cohort study. Objective The aim of this study was to determine whether the application of the Enneking classification in the management of spinal chondrosarcomas influences local recurrence and survival. Summary of background data Primary spinal chondrosarcomas are rare. Best available evidence is based on small case series, thus making it difficult to determine optimal management and risk factors for local recurrence and survival. Methods The AOSpine Knowledge Forum Tumor developed a multicenter ambispective database of surgically treated patients with spinal chondrosarcoma. Patient data pertaining to demographics, diagnosis, treatment, cross-sectional survival, and local recurrence were collected. Tumors were classified according to the Enneking classification. Patients were divided into two cohorts: Enneking appropriate (EA) and Enneking inappropriate (EI). They were categorized as EA when the final pathological assessment of the margin matched the Enneking recommendation, and otherwise, they were categorized as EI. Results Between 1987 and 2011, 111 patients (37 female; 74 male) received surgical treatment for a primary spinal chondrosarcoma at a mean age of 47.4 ± 15.8 years. Patients were followed for a median period of 3.1 years (range = 203 d-18.7 yrs). Median survival for the entire cohort was 8.4 years postoperative. After 10 years postoperative, 36 (32%) patients died and 37 (35%) patients suffered a local recurrence. Twenty-three of these 37 patients who suffered a local recurrence died. Sixty (58%) patients received an EA procedure while 44 (42%) received an EI procedure. EI patients had a higher hazard ratio for local recurrence than those who received an EA procedure (P = 0.052). Local recurrence was strongly associated with chondrosarcoma-related death (risk ratio = 3.6, P Conclusion This is the largest multicenter cohort of spinal chondrosarcomas. EA surgical management appeared to correlate with a decreased risk of local recurrence, yet no relationship with survival was found. Where possible, surgeons should strive to achieve EA margins to minimize the risk of local recurrence. Level of evidence 4.

We present the GAMA Panchromatic Data Release (PDR) constituting over 230deg$^2$ of imaging with photometry in 21 bands extending from the far-UV to the far-IR. These data complement our spectroscopic campaign of over 300k galaxies, and are compiled from observations with a variety of facilities including: GALEX, SDSS, VISTA, WISE, and Herschel, with the GAMA regions currently being surveyed by VST and scheduled for observations by ASKAP. These data are processed to a common astrometric solution, from which photometry is derived for 221,373 galaxies with r, 31 pages and 30 figures. Accepted in MNRAS. High-resolution copy available from our release site: http://gama-psi.icrar.org/ or directly via http://www.simondriver.org/mwavev05.pdf

We report on a search for new low-surface-brightness galaxies (LSBGs) using Sloan Digital Sky Survey (SDSS) data within the GAMA equatorial fields. The search method consisted of masking objects detected with SDSS photo, combining gri images weighted to maximise the expected signal-to-noise ratio (SNR), and smoothing the images. The processed images were then run through a detection algorithm that finds all pixels above a set threshold and groups them based on their proximity to one another. The list of detections was cleaned of contaminants such as diffraction spikes and the faint wings of masked objects. From these, selecting potentially the brightest in terms of total flux, a list of 343 LSBGs was produced having been confirmed using VISTA Kilo-degree Infrared Galaxy Survey (VIKING) imaging. The photometry of this sample was refined using the deeper VIKING Z band as the aperture-defining band. Measuring their $g-i$ and $J-K$ colours shows that most are consistent with being at redshifts less than 0.2. The photometry is carried out using an AUTO aperture for each detection giving surface brightnesses of $��_{r} \ge 25 \, \mathrm{mag} \, \mathrm{arcsec}^{-2}$ and magnitudes of $r > 19.8$ mag. None of these galaxies are bright enough to be within the GAMA main survey limit but could be part of future deeper surveys to measure the low-mass end of the galaxy stellar mass function., 11 pages, 8 figures, accepted by MNRAS

OBJECT A chordoma is an indolent primary spinal tumor that has devastating effects on the patient's life. These lesions are chemoresistant, resistant to conventional radiotherapy, and moderately sensitive to proton therapy; however, en bloc resection remains the preferred treatment for optimizing patient outcomes. While multiple small and largely retrospective studies have investigated the outcomes following en bloc resection of chordomas in the sacrum, there have been few large-scale studies on patients with chordomas of the mobile spine. The goal of this study was to review the outcomes of surgically treated patients with mobile spine chordomas at multiple international centers with respect to local recurrence and survival. This multiinstitutional retrospective study collected data between 1988 and 2012 about prognosis-predicting factors, including various clinical characteristics and surgical techniques for mobile spine chordoma. Tumors were classified according to the Enneking principles and analyzed in 2 treatment cohorts: Enneking-appropriate (EA) and Enneking-inappropriate (EI) cohorts. Patients were categorized as EA when the final pathological assessment of the margin matched the Enneking recommendation; otherwise, they were categorized as EI. METHODS Descriptive statistics were used to summarize the data (Student t-test, chi-square, and Fisher exact tests). Recurrence and survival data were analyzed using Kaplan-Meier survival curves, log-rank tests, and multivariate Cox proportional hazard modeling. RESULTS A total of 166 patients (55 female and 111 male patients) with mobile spine chordoma were included. The median patient follow-up was 2.6 years (range 1 day to 22.5 years). Fifty-eight (41%) patients were EA and 84 (59%) patients were EI. The type of biopsy (p < 0.001), spinal location (p = 0.018), and if the patient received adjuvant therapy (p < 0.001) were significantly different between the 2 cohorts. Overall, 58 (35%) patients developed local recurrence and 57 (34%) patients died. Median survival was 7.0 years postoperative: 8.4 years postoperative for EA patients and 6.4 years postoperative for EI patients (p = 0.023). The multivariate analysis showed that the EI cohort was significantly associated with an increased risk of local recurrence in comparison with the EA cohort (HR 7.02; 95% CI 2.96–16.6; p < 0.001), although no significant difference in survival was observed. CONCLUSIONS EA resection plays a major role in decreasing the risk for local recurrence in patients with chordoma of the mobile spine.

The National Institutes of Health recommends strategies to obtain evidence for the treatment of rare conditions such as primary tumors of the spine (PTSs). These tumors have a low incidence and are pathologically heterogeneous, and treatment approaches are diverse. Appropriate evidence-based care is imperative. Failure to follow validated oncological principles may lead to unnecessary mortality and profound morbidity. This paper outlines a scientific model that provides significant evidence guiding the treatment of PTSs.A four-stage approach was used: 1) planning: data from large-volume centers were reviewed to provide insight; 2) recruitment: centers were enrolled and provided the necessary infrastructure; 3) retrospective stage: existing medical records were reviewed and completed with survival data; and 4) prospective stage: prospective data collection has been implemented. The AOSpine Knowledge Forum Tumor designed six modules: demographic, clinical, diagnostic, therapeutic, local recurrence, survival, and perioperative morbidity data fields and provided funding.It took 18 months to implement Stages 1-3, while Stage 4 is ongoing. A total of 1495 tumor cases were captured and diagnosed as one of 18 PTS histotypes. In addition, a PTS biobank network has been created to link clinical data with tumor pathology and molecular analysis.This scientific model has not only aggregated a large amount of PTS data, but has also established an international collaborative network of spine oncology centers. Access to large volumes of data will generate further research to guide and enhance PTS clinical management. This model could be applied to other rare neoplastic conditions. Clinical trial registration no.: NCT01643174 (ClinicalTrials.gov).

Study Design, The study group consisted of 53 patients who underwent 75 operations for spine metastases. Patient and tumor demographic factors, preoperative nutritional status, and perioperative adjunctive therapy were retrospectively reviewed. Objective, To determine the risk factors for wound breakdown and infection in patients undergoing surgery for spinal metastases. Summary of Background Data. Spinal Fusion using spine implants may be associated with an infection rate of 5% or more. Surgery for spine metastases is associated with an infection rate of more than 10%. Factors other than the type of surgery performed may account for the greater infection rate. Methods. Data were obtained by reviewing patient records. Age, sex, and neurologic status of the patient; tumor type and site; and surgical details were noted. Adjunctive treatment with corticosteroids and radiotherapy was recorded, Nutritional status was evaluated by determining serum protein and serum albumin concentrations and by total lymphocyte count. Results. Wound breakdown and Infection occurred in 75 of 75 wounds. No patient or tumor demographic factors other than intraoperative blood loss (P < 0.1) were statistically associated with infection; The correlation between preoperative protein deficiency (P < 0.01) or perioperative corticosteroid administration (P < 0.10) and wound infection was significant. There was no statistical correlation between lymphocyte count or perioperative radiotherapy and wound infection. Conclusions, The results indicate that preoperative protein depletion and perioperative administration of corticosteroids are risk factors for wound infection in patients undergoing surgery for spine metastases, Perioperative correction of nutritional depletion and cessation of steroid therapy may reduce wound complications.

Study Type Retrospective cohort. Introduction The treatment of rare neoplastic conditions is challenging, especially because studies providing high levels of evidence are often lacking. Such is the case with primary tumors of the spine (PTS), which have a low incidence, are pathologically heterogeneous, and have diverse treatment approaches. 1 Despite these difficulties, appropriate evidence-based care of these complex patients is imperative. Failure to follow validated oncologic principles may lead to unnecessary mortality and profound morbidity. Objective With the aim of offering patients the most appropriate treatment based on the best available evidence, a novel scientific model was developed and employed. This article outlines this model, which has not only provided significant evidence guiding treatment of this rare condition, but we believe is readily transferrable to other similarly rare conditions. Methods A four-stage approach was employed. (1) Planning: Data from large volume centers were reviewed together with results from a feasibility questionnaire to provide insight into epidemiology, patient volumes, tumor pathology, treatment modalities, and outcomes. (2) Recruitment: Centers with sufficient volume and valid data were enrolled and provided with the necessary infrastructure. This included study coordinators and a secure, Web-based database (REDCap, Vanderbilt University, Nashville, Tennessee, United States) to capture international data from six modules comprising: demographic, clinical, diagnostic, therapeutic, local recurrence, perioperative morbidity fields, and a cross-sectional survey to update survival information. The AOSpine Knowledge Forum Tumor designed these modules and provided funding. Each center received institutional ethics approval. (3) Retrospective stage: Prospectively collected data from all recruited centers were reviewed and analyzed retrospectively. (4) Prospective stage: Following interim analysis, prospective data collection has been implemented. In addition, a PTS bio-bank network has been created to link clinical data with tumor pathology and molecular analysis. Results It took 18 months to implement stages 1 to 3 of this model and stage 4 is ongoing. A total of 1,495 tumor cases were captured and diagnosed as one of the 18 primary spine tumor subtypes listed ( Fig. 1 ). The most prevalent diagnosis was chordoma (n = 344, 23%). There were 674 females and 821 males with a mean age of 43 ± 19 years at the time of surgery. Surgical treatment was performed between 1981 and 2012. The survival at 5 and 10 years postsurgery was 71.9 and 53.3%, respectively, with a median survival of 13 years postsurgery ( Fig. 2 ). Conclusions To date, this is the largest international collection of PTS. This novel scientific model has not only aggregated a large amount of PTS data, but has also established an international collaborative network of spine oncology centers. The access to large volumes of clinical and bio-bank data will generate further research to guide and enhance the clinical management of PTS. This novel scientific model could be of similar tremendous value if applied to other rare neoplastic conditions.

Background Chordomas are rare, locally aggressive bony tumors associated with poor outcomes. Recently, the single nucleotide polymorphism (SNP) rs2305089 in the T (brachyury) gene was strongly associated with sporadic chordoma development, but its clinical utility is undetermined. Methods In 333 patients with spinal chordomas, we identified prognostic factors for local recurrence-free survival (LRFS) and overall survival and assessed the prognostic significance of the rs2305089 SNP. Results The median LRFS was 5.2 years from the time of surgery (95% CI: 3.8-6.0); greater tumor volume (≥100cm3) (hazard ratio [HR] = 1.99, 95% CI: 1.26-3.15, P = .003) and Enneking inappropriate resections (HR = 2.35, 95% CI: 1.37-4.03, P = .002) were independent predictors of LRFS. The median overall survival was 7.0 years (95% CI: 5.8-8.4), and was associated with older age at surgery (HR = 1.11 per 5-year increase, 95% CI: 1.02-1.21, P = .012) and previous surgical resection (HR = 1.73, 95% CI: 1.03-2.89, P = .038). One hundred two of 109 patients (93.6%) with available pathologic specimens harbored the A variant at rs2305089; these patients had significantly improved survival compared with those lacking the variant (P = .001), but there was no association between SNP status and LRFS (P = .876). Conclusions The ability to achieve a wide en bloc resection at the time of the primary surgery is a critical preoperative consideration, as subtotal resections likely complicate later management. This is the first time the rs2305089 SNP has been implicated in the prognosis of individuals with chordoma, suggesting that screening all patients may be instructive for risk stratification.

Despite promising advances in basic spinal cord repair research, no effective therapy resulting in major neurological or functional recovery after traumatic spinal cord injury (tSCI) is available to date. The neurological examination according to the International Standards for Neurological and Functional Classification of Spinal Cord Injury Patients (International Standards) has become the cornerstone in the assessment of the severity and level of the injury. Based on parameters from the International Standards, physicians are able to inform patients about the predicted long-term outcomes, including the ability to walk, with high accuracy. In those patients who cannot participate in a reliable physical neurological examination, magnetic resonance imaging and electrophysiological examinations may provide useful diagnostic and prognostic information. As clinical research on this topic continues, the prognostic value of the reviewed diagnostic assessments will become more accurate in the near future. These advances will provide useful information for physicians to counsel tSCI patients and their families during the catastrophic initial phase after the injury.

Introduction Spinal hemangiomas are the most common tumor of the spine, being identified in 2 to 27% of patients at autopsy and on radiographic and magnetic resonance imaging studies. The majority of spinal hemangiomas are identified incidentally with only 1% presenting with symptoms, including pain, pathologic fracture, or neurologic compromise. Because of the rarity of symptomatic presentation, optimal surgical treatment of, and risk factors for local recurrence and mortality associated with, symptomatic spinal hemangiomas remain unclear. This multicenter cohort study aims to quantify rates of local recurrence and mortality following surgical treatment of symptomatic spinal hemangiomas and to identify prognostic variables for local disease control and death. Patient and Methods: AOSpine knowledge forum tumor investigators created an ambispective database of surgically treated patients with symptomatic spinal hemangiomas. Patient data pertaining to demographics, clinical presentation, diagnosis, treatment, cross-sectional survival, local recurrence, and perioperative morbidity were collected. Tumors were classified according to Enneking and Weinstein–Boriani–Biagini. Descriptive statistics were summarized and Kaplan–Meier curves illustrated mortality and recurrence. Fisher exact and log-rank tests identified prognostic variables for recurrence and mortality. Results Between 1996 and 2012, 68 patients (mean age = 51 years, SD = 16), 43 females and 25 males, underwent surgical treatment for a spinal hemangioma with 23% ( n = 13) classified as benign aggressive. Epidural tumor extension was present in 55% of patients ( n = 33). Pain was a presenting symptom in 82% ( n = 54), 31% ( n = 20) had a pathologic fracture, and 37% ( n = 24) were neurologically compromised. Overall, 23 patients (35%) underwent preoperative embolization. Enneking appropriate surgery was performed in 79% of patients ( n = 44). Adjuvant radiotherapy was employed in 10% of patients ( n = 7). The local recurrence rate was 3% ( n = 2) with no recurrences in patients undergoing marginal or wide resection. Mortality because of the spinal hemangioma was not observed during the study period (mean follow-up = 3.9 years, SD = 3.8). Prior subtotal intralesional resection was performed in one of the two patients who had a local recurrence. Conclusion This is the largest multicenter surgical cohort of spinal hemangiomas. Although symptomatic spinal hemangiomas frequently present with epidural disease and neurologic compromise, they remain a benign tumor. Thus, formal en bloc resection, with an associated risk and increased morbidity, is not required, and excellent rates of local control and long-term survival can be obtained when strict oncologic treatment principles are followed during the index surgery.

The overall hypersensitivity reaction rate among 14,249 U.S. Marine Corps personnel who received 36,850 doses of an investigational Japanese encephalitis vaccine was 10.3 per 10,000 doses; reaction rates were 16.1 and 10.3 per 10,000 doses for the first two doses, and 2.0 per 10,000 doses for the third. The reaction rate was 26.7 per 10,000 vaccinees. Of 38 reactors, 26 had urticaria and/or angioedema, and 11 had pruritus. Vaccine reaction intervals clustered within 48 hours for dose 1, but the median reaction interval for dose 2 was 96 hours. A history of urticaria or allergic rhinitis was associated with an increased probability of a vaccine reaction.

Equilibrium constants for transfer from water to vapor, determined by dynamic vapor pressure measurements, show that the hydrophilic character of imidazole (log K(v/w) = -7.2) is no greater than might be expected on the basis of its constituent groups, whereas p-nitrophenol (log K(v/w) = -8.6) is about 30-fold more hydrophilic than would be the case if the effects of its constituent groups were additive. In contrast, the p-nitrophenolate ion (estimated log K(v/w) = -46) is less hydrophilic, by approximately 15 orders of magnitude, than might be expected if there were no interactions between its substituent groups. Thiopicric acid yields the most hydrophobic benzenoid anion that appears to have been reported thus far, its dissociated tetraethylammonium salt entering methylene chloride from water with an equilibrium constant approaching unity. The hydrophilic character of p-benzoquinone (log K(v/w) = -4.3) is much exceeded by that of p-hydroquinone (log K(v/w) = -7.5), so that solvent water exerts a major effect on the redox potential of this system. Comparison with model compounds indicates that in both p-benzoquinone and p-hydroquinone, solvation requirements of the symmetrical polar substituents are in conflict.

Some analogs of alpha-chlorohydrin were studied as an effort to improve the activity and to determine structure-activity relationships. The structural analogs were prepared and their activities in male rats were studied. Several were slightly active but only 1-amino-3-chloro-2-propanol hydrochloride was strongly active (effective dose-99 was 7-8 mg/kg/day; lethal dose-50 was 500 mg/kg). The rest were all derivatives whose activity could be rationalized by in vivo hydrolysis to give 1-amino-3-chloro-2-propanol or alpha-chlorohydrin. On resolving the amino compound an excellent separation of activity and acute toxicity was achieved. Details of these synthesis will published elsewhere.

Reading is a process in which the reader brings meaning to the printed page in order to reorganize the structure of his thinking to increase comprehension. Preston (1964) presented comprehension items (but not the reading passages) of the Cooperative English Test to college freshmen and 77 per cent of the subjects achieved scores better than chance. Imus, Rothney, and Bear (1938) reported that Opthalm-O-Graph reading comprehension scores of college students were almost as high when the comprehension test on a given passage was taken before the passage was read as after it was read. J. Harlan Shores (1968) writes: Most important of all to both reading comprehension and speed are those factors that relate the reader to the material he is reading — the background of experience he has for this material, his purpose for reading it, his interest in the field and especially in the part of it about which he is reading, his mental set with respect to this job and to this material, his familiarity with the peculiarities of style and phraseology of this author and his field, whether these new concepts are compatible with or contrary to those he already holds. Smith (1959) described how students respond to multiplechoice items. As presently prepared, one choice is usually too broad, one is too narrow, one is irrelevant and one is correct.

Equilibrium constants for transfer from water to vapor, determined by dynamic vapor pressure measurements, show that the hydrophilic character of imidazole (log K(v/w) = -7.2) is no greater than might be expected on the basis of its constituent groups, whereas p-nitrophenol (log K(v/w) = -8.6) is about 30-fold more hydrophilic than would be the case if the effects of its constituent groups were additive. In contrast, the p-nitrophenolate ion (estimated log K(v/w) = -46) is less hydrophilic, by approximately 15 orders of magnitude, than might be expected if there were no interactions between its substituent groups. Thiopicric acid yields the most hydrophobic benzenoid anion that appears to have been reported thus far, its dissociated tetraethylammonium salt entering methylene chloride from water with an equilibrium constant approaching unity. The hydrophilic character of p-benzoquinone (log K(v/w) = -4.3) is much exceeded by that of p-hydroquinone (log K(v/w) = -7.5), so that solvent water exerts a major effect on the redox potential of this system. Comparison with model compounds indicates that in both p-benzoquinone and p-hydroquinone, solvation requirements of the symmetrical polar substituents are in conflict.

The abortifacient properties of analogs of aminoglutethimide were tested in rats. Aminoglutethimide is nonsteroidal and nonestrogenic, and induces abortion in pregnant rats by interfering with the conversion of cholesterol to delta5-pregnenolone. However, the spread between efficacy (100 mg/kg) and toxicity (200 mg/kg) is not large, thus limiting its potential use in humans. A series of derivatives, Schiff b ases and an unsaturated ring system were prepared. None of the prepared analogs demonstrated the abortifacient activity of aminoglutethimide. It is concluded that the abortifacient activity of aminoglutethimide is highly specific, and that all changes made caused the activity to be lost. The experimental procedures involved in preparing the analogs are described.