Functional characterization of the G162R and D216H genetic variants of human CYP17A1.

Cytochrome P450 17A1 (CYP17A1) is a dual-function enzyme catalyzing reactions necessary for cortisol and androgen biosynthesis. CYP17A1 is a validated drug target for prostate cancer as CYP17A1 inhibition significantly reduces circulating androgens and improves survival in castration-resistant prostate cancer. Germline CYP17A1 genetic variants with altered CYP17A1 activity manifesting as various endocrinopathies are extremely rare; however, characterizing these variants provides critical insights into CYP17A1 protein structure and function. By querying the dbSNP online database and publically available data from the 1000 genomes project (http://browser.1000genomes.org), we identified two CYP17A1 nonsynonymous genetic variants with unknown consequences for enzymatic activity and stability. We hypothesized that the resultant amino acid changes would alter CYP17A1 stability or activity. To test this hypothesis, we utilized a HEK-293T cell-based expression system to characterize the functional consequences of two CYP17A1 variants, D216H (rs200063521) and G162R (rs141821705). Cells transiently expressing the D216H variant demonstrate a selective impairment of 16α-hydroxyprogesterone synthesis by 2.1-fold compared to wild-type (WT) CYP17A1, while no effect on 17α-hydroxyprogesterone synthesis was observed. These data suggest that substrate orientations in the active site might be altered with this amino acid substitution. In contrast, the G162R substitution exhibits decreased CYP17A1 protein stability compared to WT with a near 70% reduction in protein levels as determined by immunoblot analysis. This variant is preferentially ubiquitinated and degraded prematurely, with an enzyme half-life calculated to be ∼2.5 h, and proteasome inhibitor treatment recovers G162R protein expression to WT levels. Together, these data provide new insights into CYP17A1 structure-function and stability mechanisms.

Prognostic significance of supradiaphragmatic lymph nodes at initial presentation in patients with stage III high-grade serous ovarian cancer.

PURPOSE: To identify the optimal size threshold and to assess the prognostic significance of supradiaphragmatic lymph nodes at initial presentation of patients with high-grade serous ovarian cancer (HGSC). METHODS: This IRB-approved, HIPAA-compliant retrospective study included baseline pretreatment staging abdominal CTs of 88 women (mean age 62 years, SD 10.4, range 29-85) with FIGO stage III HGSC. Patients with stage IV disease were excluded due to worse prognosis and management guided by distant metastases. Two fellowship-trained radiologists independently reviewed abdominal CTs to record the presence of supradiaphragmatic nodes, abdominal lymphadenopathy, peritoneal carcinomatosis, and ovarian mass. Progression-free survival (PFS) and overall survival (OS) were recorded after median 79 months follow-up (IQR 58-115, range 13-144). The optimal short-axis size threshold for supradiaphragmatic lymphadenopathy was determined by correlating 3, 4, 5, 6, 7, and 10 mm thresholds with PFS and OS using Log-rank test. Prognostic significance of supradiaphragmatic lymphadenopathy was assessed using Cox proportional hazards models. RESULTS: There was good interobserver agreement for presence (κ = 0.65, 95%CI 0.51-0.79) and size (ICC = 0.77, 95%CI 0.66-0.86) of supradiaphragmatic nodes. 5 mm short-axis size threshold was associated with significantly shorter PFS (median 14 months, IQR 11-17 vs. 23 months, IQR 12-59; p = 0.02) and OS (median 44 months, IQR 27-69 vs. 65 months, IQR 45-96; p = 0.03). Total 38/88 (43%) patients had supradiaphragmatic lymphadenopathy. On Cox proportion hazards analysis, supradiaphragmatic lymphadenopathy was significantly associated with shorter PFS (p = 0.02; HR 1.81, 95%CI 1.11-2.96) and OS (p = 0.008; HR 2.11, 95%CI 1.21-3.65). CONCLUSION: In patients with stage III HGSC, supradiaphragmatic lymphadenopathy is associated with shorter PFS and OS. Further studies would help determine its implications on staging, decision regarding neoadjuvant therapy, and surgical technique.

A Phase I study of cyclin-dependent kinase inhibitor, AT7519, in patients with advanced cancer: NCIC Clinical Trials Group IND 177.

BACKGROUND: AT7519 is a small-molecular inhibitor of multiple cyclin-dependent kinases (CDKs). It shows encouraging anti-cancer activity against multiple cell lines and in tumour xenografts. This phase I study was conducted to evaluate the safety and tolerability of AT7519 given as 1-h intravenous infusion on days 1, 4, 8 and 11 every 3 weeks. METHODS: Patients with advanced refractory solid tumours or non-Hodgkin's lymphoma were enroled. Dose escalation occurred in a 3+3 manner based on toxicity assessment. Pharmacokinetic samples were collected after first AT7519 infusion, whereas pharmacodynamics (PD) samples were obtained in selected patients. RESULTS: Thirty-four patients were enroled, and 32 received study treatments over 4 dose levels. Dose-limiting toxicities included mucositis, febrile neutropenia, rash, fatigue and hypokalemia. The recommended phase II dose (RP2D) was 27.0 mg m(-2). Ten of 19 patients evaluable for efficacy had stable disease as the best response (median duration: 3.3 months; range: 2.5 to 11.1 months). There was no clinically significant QTc prolongation. There was an apparent dose proportional increase in AT7519 exposure. The PD studies showed reduction in markers of CDK activity in selected patients' skin biopsies post treatment. CONCLUSIONS: AT7519, when administered as an intravenous infusion on days 1, 4, 8 and 11, was well tolerated. The RP2D is 27.0 mg m(-2). At this dose level, plasma AT7519 concentrations were above the biologically active concentrations, and preliminary anti-cancer activity was observed in patients. This dosing schedule is being further evaluated in multiple phase II studies.

The risk of failure after primary orchidopexy: an 18 year review.

OBJECTIVE: To review the primary orchidopexy failure rate and outcome of repeat orchidopexy in a tertiary paediatric surgical centre and identify risk factors. METHODS: A prospectively collected and validated audits system was used to identify all boys having a repeat orchidopexy from August 1990 to December 2008 (18 years). RESULTS: In total, 1538 boys underwent orchidopexy with 1886 testicles operated on. Of these 348 (22.6%) patients had bilateral cryptorchidism. A need for repeat orchidopexy was identified in 31 boys resulting in a primary failure rate of 1.6% over the 18 years. Unilateral orchidopexy as the primary operation had a 1.5% failure rate. The failure rate for bilateral cryptorchidism was 1.87% per testicle rising to 1.93% per testicle when the primary operation was synchronous bilateral orchidopexy. Orchidopexy failure occurred in 9 patients (1.97%) who were under 24 months, 15 (2.67%) who were between 24 and 72 months and 7 (0.8%) over 72 months at time of first operation. CONCLUSION: Possible risk factors for primary orchidopexy failure are bilateral operation and older age at time of operation. Failure in achieving a satisfactory scrotal position (and testicular loss) following orchidopexy has been postulated as a potential surgical standard for revalidation of paediatric surgeons. This study adds important contemporary data to inform that process.

Regulation of mitosis and taxane response by Daxx and Rassf1.

Current theories suggest that mitotic checkpoint proteins are essential for proper cellular response to taxanes, a widely used family of chemotherapeutic compounds. We recently showed that absence or depletion of protein Daxx increases cellular taxol (paclitaxel) resistance-a common trait of patients diagnosed with several malignancies, including breast cancer. Further investigation of Daxx-mediated taxol response revealed that Daxx is important for the proper timing of mitosis progression and cyclin B stability. Daxx interacts with mitotic checkpoint protein RAS-association domain family protein 1 (Rassf1) and partially colocalizes with this protein during mitosis. Rassf1/Daxx depletion or expression of Daxx-binding domain of Rassf1 elevates cyclin B stability and increases taxol resistance in cells and mouse xenograft models. In breast cancer patients, we observed the inverse correlation between Daxx and clinical response to taxane-based chemotherapy. These data suggest that Daxx and Rassf1 define a mitotic stress checkpoint that enables cells to exit mitosis as micronucleated cells (and eventually die) when encountered with specific mitotic stress stimuli, including taxol. Surprisingly, depletion of Daxx or Rassf1 does not change the activity of E3 ubiquitin ligase anaphase promotion complex/C in in vitro settings, suggesting the necessity of mitotic cellular environment for proper activation of this checkpoint. Daxx and Rassf1 may become useful predictive markers for the proper selection of patients for taxane chemotherapy.

Pneumothorax in cystic fibrosis: prevalence and outcomes in Scotland.

BACKGROUND: Pneumothorax is a feared complication of cystic fibrosis. With improved survival into adult life the incidence of pneumothorax is expected to increase. The optimal management of these patients is unclear. METHODS: Case review of patients from the three Scottish adult CF centres. RESULTS: A total of 22 episodes of pneumothorax occurred in 20 patients over a 12year period. 2 patients died as a result of the pneumothorax. 16 pneumothoraces were treated by insertion of an intercostal drain and 8 by observation. 8 patients suffered a prolonged air leak. 5 patients were treated with pleurodesis. Pneumothorax was associated with a small decline in lung function which persisted for at least 1year. CONCLUSION: Pneumothorax can present a challenge to treat in adult CF. However successful outcomes can be achieved even in cases of prolonged air leaks. Current national guidelines help in selecting optimal pleural interventions.

Impact of bone geometry on effective properties of bone scaffolds.

The characterization of bone/scaffold composite mechanical properties is essential for translation to the clinic, but in vivo studies require resources and personnel not available to many investigators. Therefore, the ability to predict composite properties could facilitate scaffold evaluation and reduce the number of in vivo studies required. To date, there have been no studies that have used experimental data to formulate a model of bone morphology or that have examined morphology as a variable in composite properties. In this study, a simple model was developed to predict the effective elastic properties of hydroxyapatite (HA) scaffold/bone composites using representative volume elements (RVE) and finite element analysis. While the RVE for the scaffold is clear, the choice of RVE for bone is not. Two bone geometries were generated for the RVE based on data from an in vivo study: a uniform coating and bridges in pores. Three scaffolds were evaluated in order to consider the effects of scaffold material modulus and porosity. Results showed that the bone geometry had little influence on composite elastic properties when compared to experimental error from the in vivo study. The implication is that such properties can be estimated by measuring the volume fraction of bone using a non-destructive method like microcomputerized tomography and the simple RVE model.

Selective CCR2-targeted macrophage depletion ameliorates experimental mesangioproliferative glomerulonephritis.

The CCL2/CCR2 chemokine/receptor axis directs the chemotaxis of infiltrating monocytes/macrophages and T cells and plays a pivotal role in tissue damage and fibrosis in kidney diseases. The eradication of the activated leucocytes should diminish the production of inflammatory mediators, limit tissue damage and ameliorate disease. A recombinant fusion protein (OPL-CCL2-LPM) comprised of the human CCL2 (monocyte chemoattractant protein-1) chemokine fused to a truncated form of the enzymatically active A1 domain of Shigella dysenteriae holotoxin (SA1) has been developed. The CCL2 portion binds specifically to CCR2-bearing leucocytes and the fusion protein enters the cells, where the SA1 moiety inhibits protein synthesis resulting in cell death. The compound was tested in a model of anti-thymocyte serum (ATS)-induced mesangioproliferative glomerulonephritis (ATS-GN). Male rats were injected with ATS on day 0 and treated intravenously with vehicle, 50 or 100 microg/kg of OPL-CCL2-LPM Q2D from days 2, 4, 6 and 8. Urine and blood were collected on days 0, 5 and 9. Animals were sacrificed on day 9. No treatment-related effects on body weight or signs of clinical toxicity were observed. Urine protein levels were decreased in treated animals. At the highest dose, histopathological analyses of kidney sections revealed maximum reductions of 36, 31, 30 and 24% for macrophage count, glomerular lesions, alpha-smooth muscle actin and fibronectin respectively. These results indicate a significant protective effect of OPL-CCL2-LPM in this model of nephritis.

Mitochondria/nuclear signaling of alternative oxidase gene expression occurs through distinct pathways involving organic acids and reactive oxygen species.

Cultured cells of tobacco (Nicotiana tabacum L. cv Petit Havana) were used to investigate signals regulating the expression of the "model" nuclear gene encoding the alternative oxidase (AOX) (AOX1), the terminal oxidase of the mitochondrial alternative respiratory pathway. Several conditions shown to induce AOX1 mRNA accumulation also result in an increase in cellular citrate concentrations, suggesting that citrate and/or other tricarboxylic acid (TCA) cycle intermediates may be important signal metabolites. In addition, mitochondrial reactive oxygen species (ROS) production has recently been shown to be a factor mediating mitochondria-to-nucleus signaling for the expression of AOX1. We found that the exogenously supplied TCA cycle organic acids citrate, malate and 2-oxoglutarate caused rapid and dramatic increases in the steady-state level of AOX1 mRNA at low, near physiological concentrations (0.1 mM). Furthermore, an increase in AOX1 induced by the addition of organic acids occurs independently of mitochondrial ROS formation. Our results demonstrate that two separate pathways for mitochondria-to-nucleus signaling of AOX1 may exist, one involving ROS and the other organic acids.

A phase I study of AMD473 and docetaxel given once every 3 weeks in patients with advanced refractory cancer: a National Cancer Institute of Canada-Clinical Trials Group trial, IND 131.

BACKGROUND: AMD473 (previously ZD0473) is a new-generation platinum compound with activity against a wide range of human tumour cell lines and xenografts, including carboplatin- and cisplatin-resistant lines. To assess its potential combined with a taxane, a phase I study of AMD473 and docetaxel in advanced cancer was initiated by the National Cancer Institute of Canada-Clinical Trials Group. PATIENTS AND METHODS: Patients with advanced cancer, measurable disease, performance status Eastern Cooperative Oncology Group 0-2, no major organ dysfunction, and one or no previous taxane regimen received escalating doses of AMD473 and docetaxel every 3 weeks, with a starting dose of AMD473 80 mg/m(2) and docetaxel 60 mg/m(2). RESULTS: Thirty-three patients enrolled on four dose levels were evaluable for toxicity and 25 patients were evaluable for response. The maximum tolerated dose was dose level 4 (AMD473 120 mg/m(2) and docetaxel 75 mg/m(2)), with grade 4 neutropenia in both minimally and heavily pretreated patients causing dose-limiting toxicity. As well at dose level 4, one patient had grade 3 vomiting despite premedication. Dose level three was expanded for both groups of patients and was defined as the recommended phase II dose at AMD473 100 mg/m(2) and docetaxel 75 mg/m(2). Non-hematologic toxicities included fatigue, diarrhoea and other mild toxicities. There was one partial response in a patient with prostate cancer and stable disease in 15 patients. No apparent pharmacokinetic interaction was noted. CONCLUSION: AMD473 and docetaxel can be combined with a recommended phase II dose level of 100 mg/m(2) and 75 mg/m(2), respectively, given intravenously every 3 weeks. The combination has activity and should be explored in responsive tumour types.

Phase II study of troxacitabine (BCH-4556) in patients with advanced and/or metastatic renal cell carcinoma: a trial of the National Cancer Institute of Canada-Clinical Trials Group.

PURPOSE: A multi-institution phase II study was undertaken by National Cancer Institute of Canada-Clinical Trials Group to evaluate the efficacy and toxicity of intravenous troxacitabine (Troxatyl; Shire Pharmaceuticals Plc, Laval, Quebec, Canada), in patients with renal cell carcinoma. PATIENTS AND METHODS: Between June 1999 and March 2000, 35 patients (24 male) with a mean age of 60 years who had advanced and/or metastatic disease were treated with troxacitabine given as an intravenous infusion over 30 minutes at a dose of 10 mg/m2 intravenously, once every 3 weeks. RESULTS: Of the 33 of 35 patients evaluable for response, there were two confirmed partial responses, 21 patients had stable disease (median duration, 4.4 months), and 10 patients had progressive disease. Eight patients remained stable for more than 6 months, of whom six remain free of progression. The most common drug-related nonhematologic toxicities observed were skin rash (77.1%), hand-foot syndrome (68.6%), alopecia (51.4%), fatigue (51.4%), and nausea (57.1%). Out of a total of 145 cycles of treatment, 98 were given without steroid premedication, whereas 47 cycles were given with steroid premedication. Without premedication, skin rash occurred in 37% of cycles compared with 26% when steroids were given prophylactically. CONCLUSION: Troxacitabine given at a dose of 10 mg/m2 once every 3 weeks was well tolerated in patients with metastatic renal cell cancer, with common toxicities being a moderate to severe granulocytopenia and skin rash. Steroid premedication may reduce the frequency and severity of the skin rash. Our current study suggests that the nucleoside analog troxacitabine may have modest activity against renal cell carcinoma; however, larger studies are required to confirm this.

Phase II study of CGP 69846A (ISIS 5132) in recurrent epithelial ovarian cancer: an NCIC clinical trials group study (NCIC IND.116).

OBJECTIVE: ISIS 5132 is a 20-base phosphorothioate DNA oligonucleotide against human c-raf kinase, a downstream effector of ras oncogene function. C-raf kinase is a molecule in the MAP kinase signaling cascade which is essential for cellular proliferation, the overexpression of which leads to malignant expression. Activity of this compound was documented in a woman with ovarian cancer in a Phase I study. METHODS: We evaluated ISIS 5132 at a dose of 4 mg/kg/day by continuous venous infusion, administered for 21 days q 4 weeks in 22 patients with recurrent ovarian cancer in a standard two-stage Phase II design. Three patients were ineligible; 19 patients are evaluable for toxicity and 16 for response. All patients had previously received systemic therapy for ovarian cancer (6 had one and 13 had two prior regimens). Patients were treated with a median of two cycles and 79% of the patients received >90% planned dose intensity. RESULTS: ISIS 5132 was well tolerated with no episodes of Grade 3 or 4 hematologic or biochemical (creatinine, AST, bilirubin) toxicity. There were six episodes of grade 3 nonhematologic toxicity in 4 patients thought to be treatment related (lethargy 2; anorexia 1; abdominal pain 2; shortness of breath 1). No responses were seen in the 16 patients who are evaluable for response; 4 had stable disease for a median of 3.8 months and 12 patients had documented progressive disease. CONCLUSION: ISIS 5132 at 4 mg/kg/day as a single agent did not show activity in recurrent ovarian cancer.

Vasorelaxant properties of isolated human radial arteries: comparison with internal mammary arteries.

Radial arteries, used in revascularisation surgery, are prone to spasm. We have examined the ability of nitrovasodilators, calcium channel blockers, and K(ATP) channel openers to cause vasodilation, and to attenuate contractions due to depolarisation and receptor activation in radial and mammary arteries used in coronary artery bypass graft surgery. Two to three millimetre rings of artery obtained from patients at surgery were studied in organ baths in vitro. Constriction to KC1 and phenylephrine was examined before and again after treatment of the rings with drug or vehicle. Calcium channel blockers were the only compounds to inhibit contractions to both KC1 and phenylephrine. Sodium nitroprusside attenuated constriction to phenylephrine but not KC1 in both vessels. K(ATP) channel openers similarly attenuated constriction to phenylephrine in radial arteries but were much less effective in mammary arteries. These studies support the continued use of calcium blockers after revascularisation with radial artery but suggest that other classes of drug may be as effective at minimising spasm due to receptor mediated constriction.

Interactions among ascorbate, dehydroascorbate and glucose transport in cultured hippocampal neurons and glia.

There is an increasing recognition of the damaging role played by oxygen radicals in mediating necrotic neuronal injury. As such, it becomes important to understand the transport mechanisms that help maintain appropriate levels of small molecule antioxidants such as ascorbate in the brain. It has long been known that the transport of dehydroascorbate (DHA) into a variety of cell types is accomplished through the Glut-1 glucose transporter. In this paper, we characterize interactions among the transports of ascorbate, DHA and glucose in hippocampal cultures. We find: (a) sodium-dependent transport of ascorbate in mixed neuronal/glial, pure glial, and neuron-enriched hippocampal cultures; in contrast, we observed no such transport of DHA; (b) such ascorbate transport appeared to be independent of the glucose transporter, in that glucose did not compete for such transport, and overexpression of the Glut-1 glucose transporter did not alter ascorbate uptake; (c) in contrast, ascorbate, at concentrations ranging from 1 to 20 mM inhibited 2-dexogyglucose transport in mixed, glial and enriched neuronal hippocampal cultures; (d) potentially, ascorbate, by acting as an electron donor, could impair the function of molecules involve in the transport or metabolism of glucose. We observed mild inhibition of glucose transport by one unrelated electron donor (glutathione). Moreover, transport was also inhibited by an ascorbate analog which is not an electron donor. Thus, we conclude that ascorbate transport in hippocampal neurons and glia occurs independent of the glucose transporter but that, nevertheless, ascorbate, at concentrations generally thought to be supraphysiological, has the potential for disrupting glucose transport.

Dissecting the electrostatic interactions and pH-dependent activity of a family 11 glycosidase.

Previous studies of the low molecular mass family 11 xylanase from Bacillus circulans show that the ionization state of the nucleophile (Glu78, pK(a) 4.6) and the acid/base catalyst (Glu172, pK(a) 6.7) gives rise to its pH-dependent activity profile. Inspection of the crystal structure of BCX reveals that Glu78 and Glu172 are in very similar environments and are surrounded by several chemically equivalent and highly conserved active site residues. Hence, there are no obvious reasons why their apparent pK(a) values are different. To address this question, a mutagenic approach was implemented to determine what features establish the pK(a) values (measured directly by (13)C NMR and indirectly by pH-dependent activity profiles) of these two catalytic carboxylic acids. Analysis of several BCX variants indicates that the ionized form of Glu78 is preferentially stabilized over that of Glu172 in part by stronger hydrogen bonds contributed by two well-ordered residues, namely, Tyr69 and Gln127. In addition, theoretical pK(a) calculations show that Glu78 has a lower pK(a) value than Glu172 due to a smaller desolvation energy and more favorable background interactions with permanent partial charges and ionizable groups within the protein. The pK(a) value of Glu172 is in turn elevated due to electrostatic repulsion from the negatively charged glutamate at position 78. The results also indicate that all of the conserved active site residues act concertedly in establishing the pK(a) values of Glu78 and Glu172, with no particular residue being singly more important than any of the others. In general, residues that contribute positive charges and hydrogen bonds serve to lower the pK(a) values of Glu78 and Glu172. The degree to which a hydrogen bond lowers a pK(a) value is largely dependent on the length of the hydrogen bond (shorter bonds lower pK(a) values more) and the chemical nature of the donor (COOH > OH > CONH(2)). In contrast, neighboring carboxyl groups can either lower or raise the pK(a) values of the catalytic glutamic acids depending upon the electrostatic linkage of the ionization constants of the residues involved in the interaction. While the pH optimum of BCX can be shifted from -1.1 to +0.6 pH units by mutating neighboring residues within the active site, activity is usually compromised due to the loss of important ground and/or transition state interactions. These results suggest that the pH optima of an enzyme might be best engineered by making strategic amino acid substitutions, at positions outside of the "core" active site, that electrostatically influence catalytic residues without perturbing their immediate structural environment.

Isolation of a CONSTANS ortholog from Pharbitis nil and its role in flowering.

The short-day plant Pharbitis nil is a model plant for the study of photoperiodic control of floral initiation. Flower formation can be induced at the cotyledon stage by a single long night of at least 14 h in duration. Using differential display of mRNA we identified a P. nil ortholog of the Arabidopsis CONSTANS (CO) gene, which will be referred to as PnCO. Expression of PnCO was high after a 14-h night, but low when the dark period was 12 h or less. Our results indicate that the level of the PnCO transcript is photoperiodically regulated. After transfer from continuous light to darkness, PnCO showed a circadian pattern of expression. Expression of the CAB gene, which is a molecular marker for the circadian clock, exhibited a different pattern of expression than did PnCO and was not subject to the same photoperiodic control. A major portion of the PnCO transcripts contained an unspliced intron. Only the intron-free PnCO was able to complement the co mutant of Arabidopsis by shortening the time to flower.

Role of copper ions and cytochrome P450 in the vasodilator actions of the nitroxyl anion generator, Angeli's salt, on rat aorta.

Since copper ions catalyse the oxidation of nitroxyl anion to nitric oxide, we investigated whether this might explain the vasodilator actions of the nitroxyl generator, Angeli's salt, in rat aorta. Parallel studies were conducted with S-nitroso-N-acetyl-D,L-penicillamine (SNAP), since Cu ions catalyse the liberation of nitric oxide from this compound. Copper sulphate enhanced relaxation to Angeli's salt and SNAP but this resulted from reduced destruction of nitric oxide by superoxide rather than from enhanced generation of nitric oxide, since it was mimicked by superoxide dismutase and by the superoxide dismutase mimetic, MnCl2. Results with the selective Cu2+ chelators, neocuproine and bathocuproine disulfonate, and the Cu2+ chelators, EDTA, cuprizone and diethyldithiocarbamate, confirmed an important role for endogenous copper in mediating relaxation to SNAP but suggested only a minor role for Angeli's salt. Relaxation to Angeli's salt was, however, powerfully blocked by proadifen, suggesting an important role for cytochrome P450.

Towards non-invasive screening of skin lesions by near-infrared spectroscopy.

A noninvasive tool for skin tumor diagnosis would be a useful clinical adjunct. The purpose of this study was to determine whether near-infrared spectroscopy can be used to noninvasively characterize skin lesions. In vivo visible- and near-infrared spectra (400--2500 nm) of skin neoplasms (actinic keratoses, basal cell carcinomas, banal common acquired melanocytic nevi, dysplastic melanocytic nevi, actinic lentigines, and seborrheic keratoses) were collected by placing a fiberoptic probe on the skin. Paired t tests, repeated measures analysis of variance and linear discriminant analysis were used to determine whether significant spectral differences existed and whether spectra could be classified according to lesion type. Paired t tests showed significant differences (p < 0.05) between normal skin and skin lesions in several areas of the near-infrared spectrum. In addition, significant differences were found between the lesion groups by analysis of variance. Linear discriminant analysis classified spectra from benign lesions compared with premalignant or malignant lesions with high accuracy. Near-infrared spectroscopy is a promising noninvasive technique for the screening of skin lesions.