A prospective comparison of computer-navigated and fluoroscopic-guided in situ fixation of slipped capital femoral epiphysis.

BACKGROUND: Slipped capital femoral epiphysis (SCFE) is usually treated with percutaneous in situ screw fixation to prevent further progression of deformity. The purpose of this investigation is to compare computer navigation (CN) techniques with traditional fluoroscopic (fluoro) techniques for in situ fixation of SCFE. METHODS: This study was an IRB-approved prospective study of 39 hip pinnings in 33 children. CN techniques were used in 22 cases and fluoro in 17. The CN and fluoro groups were statistically similar in terms of grade and acuity of the slip. Children were assigned to the groups based on the intraoperative imaging technique used by the attending on call, with 3 surgeons in each group taking equal amounts of call. The "approach-withdraw" technique was used in all cases. Postoperative limited-cut, reduced-dose computed tomography (CT) scans were obtained to evaluate screw placement. This included blinded analysis for screw penetration of the joint, screw tip-to-apex distance, the distance the screw passed to the center of the physis, and attainment of center-center position. The number of pin passes, intraoperative radiation exposure, and operating room (OR) time were also analyzed. Statistics used included ANOVA, the χ and median tests. RESULTS: Compared with the fluoro group, CN resulted in more accurate screw placement. There was 1 case of joint penetration in the fluoro group not appreciated intraoperatively but detected on postoperative CT. CN also resulted in statistically significant (P < 0.05) reduced screw tip-to-apex distance and distance to the center of the physis. There was no statistically significant difference between the 2 groups in attainment of the center-center position, number of pin passes, or intraoperative radiation exposure. OR time averaged 19 minutes longer in the CN group. There was no case of avascular necrosis or chondrolysis in either of the groups. CONCLUSIONS: Compared with traditional fluoro techniques, CN in situ fixation of SCFE results in more accurate screw placement, comparable number of pin passes and intraoperative radiation exposure, and increased OR time. The cost-benefit ratio of this technology requires careful consideration at each individual institution. LEVEL OF EVIDENCE: II.

Photocytotoxicity of the fluorescent nonsteroidal androgen receptor ligand TDPQ.

1,2,3,4-tetrahydro-2,2-dimethyl-6-(trifluoromethyl)-8-pyridono[5,6-g]quinoline (TDPQ), a selective nonsteroidal androgen receptor (AR) ligand, is a fluorescent compound. We characterized its spectral properties in comparison with the structural precursor carbostyril 151 (C151) and with its racemic structural isomer 4-ethyl-1,2,3,4-tetrahydro-6-(trifluoromethyl)-8-pyridino[5,6-g]quinoline (ETPQ). The absorption maximum in CH3CN of either TDPQ or ETPQ is 400 nm whereas that of C151 is 350 nm. The fluorescence lifetimes (tau) and quantum yields (phif) in CH3CN are typical of fluorescent dyes: TDPQ (4.2 ns, 0.8) and ETPQ (4.6 ns, 0.76). C151 showed lower tau and phif of 0.2 ns and 0.02, respectively. TDPQ can function as a fluorescent label at (sub)micromolar concentrations. We detected TDPQ fluorescence in human breast tumor cells using confocal microscopy. While the fluorescence maxima of the compounds were solvent insensitive, the phif for ETPQ decreased in aqueous solutions regardless of the presence of albumin or DNA. The phif of TDPQ was less affected. The quantum yield of singlet oxygen (1O2) photosensitization (phiso) by TDPQ and ETPQ was about 7% in CH3CN, sufficient to induce photocytotoxicity. TDPQ was photocytotoxic in AR-positive MDA-MB-453 breast cancer cells but not in AR-negative MDA-MB-231 cells. The combination of AR selectivity with photocytotoxicity makes TDPQ a promising candidate for selective targeting of AR-positive cells during photodynamic therapy.

Androgen receptor-mediated apoptosis is regulated by photoactivatable androgen receptor ligands.

We have studied nonsteroidal ligands of the human androgen receptor (hAR) and have shown elsewhere that when photoactivated by visible light they collide with O2 to yield singlet oxygens (1O2) in vitro. Here we report cell killing after brief light activation (405 nm) of 1,2,3,4-tetrahydro-2,2-dimethyl-6-(trifluoromethyl)-8-pyridono[5,6-g]quinoline (TDPQ) in human prostate tumor cells. TDPQ/AR complexes were required for the death response because AR-positive LNCaP cells were killed, whereas AR-negative PC-3 cells were resistant. Excess dihydrotestosterone (DHT) blocked the TDPQ effect when the two were added together; irradiation of cells containing DHT alone had no effect. When LNCaP AR expression was suppressed using small interfering oligonucleotides targeting AR, photocytotoxicity was diminished. Conversely, stable transfection of hAR into PC-3 cells made the cells photosensitive to TDPQ. Similar results were obtained using a structural isomer of TDPQ, and also the synthetic steroidal AR ligand R1881. Cell death occurred via apoptosis as demonstrated by annexin V immunostaining, nuclear condensation, and caspase inhibition. Death involved oxidative stress, because it was prevented by addition of the antioxidant ascorbic acid during photoactivation. Detection of elevated levels of 8-hydroxy-2'-deoxyguanosine in nuclei of irradiated cells indicated oxidative DNA damage. Apoptosis spread into adjacent nonirradiated cells by direct cell-cell contacts, indicative of a bystander effect. Other photoactivatable ligands are described, implying a general method for ablation of cells bearing specific nuclear hormone receptors.

An orally active selective androgen receptor modulator is efficacious on bone, muscle, and sex function with reduced impact on prostate.

A number of conditions, including osteoporosis, frailty, and sexual dysfunction in both men and women have been improved using androgens. However, androgens are not widely used for these indications because of the side effects associated with these drugs. We describe an androgen receptor (AR) ligand that maintains expected anabolic activities with substantially diminished activity in the prostate. LGD2226 is a nonsteroidal, nonaromatizable, highly selective ligand for the AR, exhibiting virtually no affinity for the other intracellular receptors. We determined that AR bound to LGD2226 exhibits a unique pattern of protein-protein interactions compared with testosterone, fluoxymesterone (an orally available steroidal androgen), and other steroids, suggesting that LGD2226 alters the conformation of the ligand-binding domain. We demonstrated that LGD2226 is fully active in cell-based models of bone and muscle. LGD2226 exhibited anabolic activity on muscle and bone with reduced impact on prostate growth in rodent models. Biomechanical testing of bones from animals treated with LGD2226 showed strong enhancement of bone strength above sham levels. LGD2226 was also efficacious in a sex-behavior model in male rats measuring mounts, intromissions, ejaculations, and copulation efficiency. These results with an orally available, nonaromatizable androgen demonstrate the important role of the AR and androgens in mediating a number of beneficial effects in bone, muscle, and sexual function independent from the conversion of androgens into estrogenic ligands. Taken together, these results suggest that orally active, nonsteroidal selective androgen receptor modulators may be useful therapeutics for enhancing muscle, bone, and sexual function.

Novel series of potent, nonsteroidal, selective androgen receptor modulators based on 7H-[1,4]oxazino[3,2-g]quinolin-7-ones.

Recent interest in orally available androgens has fueled the search for new androgens for use in hormone replacement therapy and as anabolic agents. In pursuit of this, we have discovered a series of novel androgen receptor modulators derived from 7H-[1,4]oxazino[3,2-g]quinolin-7-ones. These compounds were synthesized and evaluated in competitive binding assays and an androgen receptor transcriptional activation assay. A number of compounds from the series demonstrated single-digit nanomolar agonist activity in vitro. In addition, lead compound (R)-16e was orally active in established rodent models that measure androgenic and anabolic properties of these agents. In this assay, (R)-16e demonstrated full efficacy in muscle and only partially stimulated the prostate at 100 mg/kg. These data suggest that these compounds may be utilized as selective androgen receptor modulators or SARMs. This series represents a novel class of compounds for use in androgen replacement therapy.

Discovery of 6-N,N-bis(2,2,2-trifluoroethyl)amino- 4-trifluoromethylquinolin-2(1H)-one as a novel selective androgen receptor modulator.

The androgen receptor is a member of the extended family of nuclear receptors and is widely distributed throughout the body. Androgen therapy is used to compensate for low levels of the natural hormones testosterone (T) and dihydrotestosterone and consists of administration of T, prodrugs thereof, or synthetic androgens. However, currently available androgens have many drawbacks. We identified 6-dialkylamino-4-trifluoromethylquinolin-2(1H)-ones as orally available tissue-selective androgen receptor modulators.

Meclizine is an agonist ligand for mouse constitutive androstane receptor (CAR) and an inverse agonist for human CAR.

The constitutive androstane receptor (CAR, NR1I3) is a key regulator of xenobiotic and endobiotic metabolism. The ligand-binding domains of murine (m) and human (h) CAR are divergent relative to other nuclear hormone receptors, resulting in species-specific differences in xenobiotic responses. Here we identify the widely used antiemetic meclizine (Antivert; Bonine) as both an agonist ligand for mCAR and an inverse agonist for hCAR. Meclizine increases mCAR transactivation in a dose-dependent manner. Like the mCAR agonist 1,4-bis[2-(3,5-dichloropyridyloxy)]benzene, meclizine stimulates binding of steroid receptor coactivator 1 to the murine receptor in vitro. Meclizine administration to mice increases expression of CAR target genes in a CAR-dependent manner. In contrast, meclizine suppresses hCAR transactivation and inhibits the phenobarbital-induced expression of the CAR target genes, cytochrome p450 monooxygenase (CYP)2B10, CYP3A11, and CYP1A2, in primary hepatocytes derived from mice expressing hCAR, but not mCAR. The inhibitory effect of meclizine also suppresses acetaminophen-induced liver toxicity in humanized CAR mice. These results demonstrate that a single compound can induce opposite xenobiotic responses via orthologous receptors in rodents and humans.

5-benzylidene-1,2-dihydrochromeno[3,4-f]quinolines as selective progesterone receptor modulators.

A series of 5-benylidene-1,2-dihydrochromeno[3,4-f]quinolines (4) were synthesized and tested in bioassays to evaluate their progestational activities, receptor- and tissue-selectivity profiles as selective progesterone receptor modulators (SPRMs). Most of the new analogues exhibited as highly potent progestins with more than 100-fold receptor selectivity over other steroid hormone receptors and LG120920 (7b) demonstrated tissue selectivity toward uterus and vagina versus breasts in a rodent model after oral administration.

Career choices in the biosciences: what companies are looking for when they are filling a position.

Holding a Ph.D. or other doctoral degree in the biological sciences used to allow for only one main career path. Faculty positions at either research-intensive universities or at predominantly teaching institutions defined the career path very well. The situation is considerably more complex now. Many individuals decide to pursue careers in for-profit organizations, either by personal preference, geographic needs, or simply as an expedient way to continue in biology in a meaningful way. This article arises from the need to define a better understanding of the nature of corporate job seeking for potential job applicants. The author draws upon his experience over a thirty-year scientific career in industry and academics. The distinctions he makes are helpful for job-seekers in this new environment.

An operative approach to address severe genu valgum deformity in the Ellis-van Creveld syndrome.

BACKGROUND: The genu valgum deformity seen in the Ellis-van Creveld syndrome is one of the most severe angular deformities seen in any orthopaedic condition. It is likely a combination of a primary genetic-based dysplasia of the lateral portion of the tibial plateau combined with severe soft-tissue contractures that tether the tibia into valgus deformations. Progressive weight-bearing induces changes, accumulating with growth, acting on the initially distorted and valgus-angulated proximal tibia, worsening the deformity with skeletal maturation. The purpose of this study is to present a relatively large case series of a very rare condition that describes a surgical technique to correct the severe valgus deformity in the Ellis-van Creveld syndrome by combining extensive soft-tissue release with bony realignment. METHODS: A retrospective review examined 23 limbs in 13 patients with Ellis-van Creveld syndrome that were surgically corrected by two different surgeons from 1982 to 2011. Seven additional patients were identified, but excluded due to insufficient chart or radiographic data. A successful correction was defined as 10° or less of genu valgum at the time of surgical correction. Although not an outcomes study, maintenance of 20° or less of genu valgum was considered desirable. Average age at surgery was 14.7 years (range 7-25 years). Clinical follow-up is still ongoing, but averages 5.0 years (range 2 months to 18 years). Charts and radiographs were reviewed for complications, radiographic alignment, and surgical technique. The surgical procedure was customized to each patient's deformity, consisting of the following steps: 1. Complete proximal to distal surgical decompression of the peroneal nerve 2. Radical release and mobilization of the severe quadriceps contracture and iliotibial band contracture 3. Distal lateral hamstring lengthening/tenotomy and lateral collateral ligament release 4. Proximal and distal realignment of the subluxed/dislocated patella, medial and lateral retinacular release, vastus medialis advancement, patellar chondroplasty, medial patellofemoral ligament plication, and distal patellar realignment by Roux-Goldthwait technique or patellar tendon transfer with tibial tubercle relocation 5. Proximal tibial varus osteotomy with partial fibulectomy and anterior compartment release 6. Occasionally, distal femoral osteotomy RESULTS: In all cases, the combination of radical soft-tissue release, patellar realignment and bony osteotomy resulted in 10° or less of genu valgum at the time of surgical correction. Complications of surgery included three patients (five limbs) with knee stiffness that was successfully manipulated, one peroneal nerve palsy, one wound slough and hematoma requiring a skin graft, and one pseudoarthrosis requiring removal of hardware and repeat fixation. At last follow-up, radiographic correction of no more than 20° of genu valgum was maintained in all but four patients (four limbs). Two patients (three limbs) had or currently require revision surgery due to recurrence of the deformity. CONCLUSION: The operative approach presented in this study has resulted in correction of the severe genu valgum deformity in Ellis-van Creveld syndrome to 10° or less of genu valgum at the time of surgery. Although not an outcomes study, a correction of no more than 20° genu valgum has been maintained in many of the cases included in the study. Further clinical follow-up is still warranted. LEVEL OF EVIDENCE: IV.

Modelling competition and hybridization between native cutthroat trout and nonnative rainbow and hybrid trout.

Native salmonid fish have been displaced worldwide by nonnatives through hybridization, competition, and predation, but the dynamics of these factors are poorly understood. We apply stochastic Lotka-Volterra models to the displacement of cutthroat trout by rainbow/hybrid trout in the Snake River, Idaho, USA. Cutthroat trout are susceptible to hybridization in the river but are reproductively isolated in tributaries via removal of migratory rainbow/hybrid spawners at weirs. Based on information-theoretic analysis, population data provide evidence that hybridization was the primary mechanism for cutthroat trout displacement in the first 17 years of the invasion. However, under some parameter values, the data provide evidence for a model in which interaction occurs among fish from both river and tributary subpopulations. This situation is likely to occur when tributary-spawned cutthroat trout out-migrate to the river as fry. The resulting competition with rainbow/hybrid trout can result in the extinction of cutthroat trout even when reproductive segregation is maintained.

Potent, nonsteroidal selective androgen receptor modulators (SARMs) based on 8H-[1,4]oxazino[2,3-f]quinolin-8-ones.

A series of androgen receptor modulators based on 8H-[1,4]oxazino[2,3-f]quinolin-8-ones was synthesized and evaluated in an androgen receptor transcriptional activation assay. The most potent analogues from the series exhibited single-digit nanomolar potency in vitro. Compound 18h demonstrated full efficacy in the maintenance of muscle weight, at 10 mg/kg, with reduced activity in prostate weight in an in vivo model of androgen action.

Position of immobilization for pediatric forearm fractures.

The purpose of this study was to evaluate the effect of forearm position on residual fracture angulation for pediatric distal-third forearm fractures at the time of union. One hundred nine pediatric distal-third forearm fractures undergoing closed reduction and casting were prospectively randomized to be immobilized in pronated, supinated, or neutral position. Initial angulation and displacements were radiographically compared with healed fracture angulation at a minimum of 6 weeks. With 99 complete patient files, 38 fractures were casted in neutral, 26 in pronated, and 35 in supinated positions. Average initial angulation was 20 degrees; postreduction angulation measured 3 degrees. Final angulation at union averaged 7 degrees for all fractures. Forearm position failed to show a significant effect on fracture angulation at union. Residual fracture angulation at the time of union for pediatric distal-third forearm fractures was not significantly affected by forearm position (pronation, supination, neutral) during cast immobilization.

Synthesis and biological activity of 5-methylidene 1,2-dihydrochromeno[3,4-f]quinoline derivatives as progesterone receptor modulators.

A series of 5-methylidene 1,2-dihydrochromeno[3,4-f]quinoline derivatives were synthesized and tested in biological assays to evaluate scope and limitations of the nonsteroidal SPRM pharmacophore (3). A number of orally available highly potent nonsteroidal modulators were identified by modification of the substituents at 5-methylidene position.

Development of progesterone receptor antagonists from 1,2-dihydrochromeno[3,4-f]quinoline agonist pharmacophore.

A series of 1,2-dihydrochromeno[3,4-f]quinoline derivatives was synthesized and tested in biological assays to evaluate the nonsteroidal progesterone receptor modulator pharmacophore (4) as antiprogestins. A number of potent analogues were identified by modification of the substituents at the D-ring.