Theoretical versus empirical measures of retinal magnification for scaling AOSLO images.

The adaptive optics scanning light ophthalmoscope (AOSLO) allows cellular resolution imaging of the living retina. The accuracy of many quantitative measurements made from these images requires accurate estimates of the lateral scale of the images. Here, we used trial lenses, which are known to affect the relative magnification of the retinal image, to compare empirical measures of image scale with theoretical estimates from a four-surface optical model. The theoretical optical model overestimated the empirically determined change in image scale in 70% of the subjects examined, albeit to varying degrees. While the origin for the differences between subjects is not known, residual accommodation during imaging likely contributes to this variability in retinal magnification. These data provide an opportunity to derive improved lateral scaling error estimates for structural metrics extracted from AOSLO retinal images.

Cardiovascular collapse following povidone-iodine wash.

We present a case study of a severe episode of iodine toxicity following povidone-iodine wash with clinical manifestations of cardiovascular collapse, metabolic acidosis, renal failure and seizures. Povidone-iodine has been used as a medical antiseptic and disinfectant since 1952 Iodine toxicity secondary to povidone-iodine use is rare. Iodine toxicity is difficult to diagnose and the diagnosis is made by a high index of suspicion. Toxicity due to iodine correlates with serum and urine iodine levels. Treatment of iodine toxicity is supportive. A review of literature relating to the components of povidone-iodine, iodine metabolism, its manifestations and management of iodine toxicity secondary to povidone-iodine is also presented. An Ovid-Medline search from 1950 to 2009 revealed 1236 articles on the clinical manifestations of povidone-iodine usage but no article on iodine toxicity relating to povidone-iodine based on the following search criteria: povidone-iodine and/or iodine toxicity secondary to povidone-iodine (limited to English language, review articles, full text and human patients).

Procedimientos intervencionales guiados por ultrasonido en radiología musculoesquelética / Ultrasound guided interventional procedures in musculoskeletal radiology

Ultrasound is a useful diagnostic modality to study many structures such as subcutaneous tissue, tendons, muscles, joints, and nerves. It has low cost, wide availability and high resolution. These advantages make ultrasound a good modality in interventional procedures like soft tissue tumors biopsy, aspiration of cysts and other collections, and also in treating symptomatic calcifications like deposition of hidroxiapatite crystals in the rotator cuff, among other indications. Our objetive is to present the experience of the authors in performing musculoskeletal interventional procedures by ultrasound.

El ultrasonido es una modalidad imaginológica útil para el estudio de múltiples estructuras, tales como tejidos subcutáneos, tendones, músculos, articulaciones y nervios. Tiene un bajo costo, amplia disponibilidad y alta resolución. Estas ventajas hacen del ultrasonido una excelente modalidad en procedimientos intervencionales tales como biopsias de tejidos de partes blandas, aspiración de quistes y otras colecciones y también en el tratamiento de calcificaciones sintomáticas, tales como depósitos de cristales de hidroxiapatita de calcio en el manguito rotador. Este artículo desea mostrar la experiencia de los autores en la realización de procedimientos intervencionales musculoesqueléticos guiados por ultrasonido.

Nano-electromechanical displacement sensing based on single-walled carbon nanotubes.

We present a nano-electromechanical system based on an individual single-walled carbon nanotube (SWNT) demonstrating their potential use for future displacement sensing at the nanoscale. The fabrication and characterization of the proposed nanoscaled transducer, consisting of a suspended metal cantilever mounted on top of the center of a suspended SWNT, is presented and discussed. The displacement of the nanoscale cantilever is detected via the electromechanically induced change in conductance of the strained SWNT. A relative differential resistance sensitivity (for a metallic SWNT) of up to 27.5%/nm was measured and a piezoresistive gauge factor of a SWNT of up to 2900 was extracted.

Avances en el diagnóstico de la Enfermedad de Parkinson: ecografía transcraneal / Advances in diagnosis of Parkinson Disease: transcranial ultrasonography

La ecografía transcraneal constituye una herramienta nueva y muy útil en el estudio de la patología de los ganglios basales. Se describe su utilidad en el diagnóstico de la Enfermedad de Parkinson y otros parkinsonismos al mostrar cambios en la ecogenicidad de la sustancia nigra (SN), sitio clave en la fisiopatología de la enfermedad. En otros cuadros como temblor esencial y parkinsonismo por fármacos, es normal, a menos que haya susceptibilidad a desarrollar parkinsonismo. Por lo tanto constituye un método complementario a la clínica, económico y no invasivo, asequible para el paciente y que debe utilizarse más en nuestro medio.

Detection of Phytophthora ramorum Blight in Oregon Nurseries and Completion of Koch's Postulates on Pieris, Rhododendron, Viburnum, and Camellia.

Phytophthora ramorum, the cause of sudden oak death in California and Oregon coastal forests and ramorum blight in European nurseries and landscapes (1), was detected in six Oregon nurseries in Jackson, Clackamas, and Washington counties from May to June 2003. The pathogen was isolated from: Viburnum bodnantense 'Dawn', V. plicatum var. tomentosum 'Mariesii', Pieris japonica × formosa 'Forest Flame', P. japonica 'Variegata' and 'Flaming Silver', P. floribunda × japonica 'Brouwer's Beauty', Camellia sasanqua 'Bonanza' and other cultivars, C. japonica, and Rhododendron × 'Unique'. Samples of symptomatic tissues were plated on a Phytophthora-selective medium (PARP) and tested by polymerase chain reaction (PCR) (3). All samples positive for P. ramorum with PCR yielded P. ramorum isolates in culture. The isolates have the European genotype, mating type A1, except for the Camellia spp. isolates, which have the North American genotype, mating type A2 (2). Isolates are deposited in the American Type Culture Collection. Koch's postulates for this pathogen have been completed on V. bodnantense and C. japonica (1). To confirm pathogenicity on the new hosts, isolates from V. plicatum var. tomentosum 'Mariesii', Pieris × 'Forest Flame', Pieris × 'Brouwer's Beauty', and P. japonica 'Variegata' and 'Flaming Silver' were used to inoculate healthy plants of the same cultivars. For isolates from Rhododendron × 'Unique' and C. sasanqua 'Bonanza', pathogenicity was tested on Rhododendron × 'Nova Zembla' and C. sasanqua 'Sutsugekka' and 'Kanjiro'. Three to five plants of each cultivar were inoculated and three to five were noninoculated. Zoospore inoculum was prepared on dilute V8 agar for one isolate from each host. Foliage of plants growing in 10-cm pots was dipped for 5 sec in a zoospore suspension (3 × 104 zoospores per ml) or sprayed to runoff with a hand mister (6 × 104 zoospores per ml). Control plants were dipped in or sprayed with sterile water. C. sasanqua plants were also inoculated by placing 6-mm mycelial plugs on individual leaves that had been wounded by piercing with a pin. Control leaves were wounded but not inoculated. Foliage was enclosed in plastic bags to retain humidity and the pathogen, and plants were incubated in a locked growth chamber (21 to 23°C). After 21 days, plants were examined for symptoms, and isolations onto PARP were made. All inoculated plants showed foliar symptoms, and P. ramorum was consistently isolated from inoculated plants, but not from asymptomatic control plants. On Rhododendron × 'Nova Zembla', nearly all leaves were wilted and dead, as were terminal buds and stems. Pieris spp. cultivars exhibited leaf and stem necrosis and defoliation. On V. plicatum var. tomentosum 'Mariesii', necrotic leaf lesions and defoliation of the lower leaves were observed. On C. sasanqua, necrotic lesions developed only on wounded leaves inoculated with mycelial plugs; these leaves abscised. Our results confirm the pathogenicity of Oregon nursery isolates of P. ramorum on V. plicatum var. tomentosum 'Mariesii', P. japonica × formosa 'Forest Flame', P. japonica 'Variegata' and 'Flaming Silver', P. floribunda × japonica 'Brouwer's Beauty', C. sasanqua and Rhododendron and complete Koch's postulates for several new hosts. References: (1) J. M. Davidson et al. Online publication. doi:10.1094/PHP-2003-0707-01-DG. Plant Health Progress, 2003. (2) E. M. Hansen et al. Plant Dis. 87:1267, 2003. (3) L. M. Winton and E. M. Hansen. For. Pathol. 31:275, 2001.

Sage advice. Experienced physician executives share the secrets of their success. Interview by David O. Weber.

Seven successful physician executives, now retired from distinguished careers, look back over their experiences and offer advice for those who follow. Be a good doctor first, and never let business interests undermine the ethics of the health care profession. Prepare for management responsibilities with business training. Seek out mentors and develop a network of knowledgeable colleagues and advisors. Exert leadership rather than authority. Expect disappointments and arm yourself for them.

Inhibition of insect juvenile hormone epoxide hydrolase: asymmetric synthesis and assay of glycidol-ester and epoxy-ester inhibitors of trichoplusia ni epoxide hydrolase.

Juvenile hormone (JH) undergoes metabolic degradation by two major pathways involving JH esterase and JH epoxide hydrolase (EH). While considerable effort has been focussed on the study of JH esterase and the development of inhibitors for this enzyme, much less has been reported on the study of JH-EH. In this work, the asymmetric synthesis of two classes of inhibitors of recombinant JH-EH from Trichoplusia ni, a glycidol-ester series and an epoxy-ester series is reported. The most effective glycidol-ester inhibitor, compound 1, exhibited an I(50) of 1.2x10(-8) M, and the most effective epoxy-ester inhibitor, compound 11, exhibited an I(50) of 9.4x10(-8) M. The potency of the inhibitors was found to be dependent on the absolute configuration of the epoxide. In both series of inhibitors, the C-10 R-configuration was found to be significantly more potent that the corresponding C-10 S-configuration. A mechanism for epoxide hydration catalyzed by insect EH is also presented.

Comparative metabolism of chloroacetamide herbicides and selected metabolites in human and rat liver microsomes.

Acetochlor [2-chloro-N-(ethoxymethyl)-N-(2-ethyl-6-methyl-phenyl)-acetamide], alachlor [N-(methoxymethyl)-2-chloro-N-(2, 6-diethyl-phenyl)acetamide], butachlor [N-(butoxymethyl)-2-chloro-N-(2,6-diethyl-phenyl)acetamide], and metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl) acetamide] are pre-emergent herbicides used in the production of agricultural crops. These herbicides are carcinogenic in rats: acetochlor and alachlor cause tumors in the nasal turbinates, butachlor causes stomach tumors, and metolachlor causes liver tumors. It has been suggested that the carcinogenicity of these compounds involves a complex metabolic activation pathway leading to a DNA-reactive dialkylbenzoquinone imine. Important intermediates in this pathway are 2-chloro-N-(2,6-diethylphenyl)acetamide (CDEPA) produced from alachlor and butachlor and 2-chloro-N-(2-methyl-6-ethylphenyl)acetamide (CMEPA) produced from acetochlor and metolachlor. Subsequent metabolism of CDEPA and CMEPA produces 2,6-diethylaniline (DEA) and 2-methyl-6-ethylaniline (MEA), which are bioactivated through para-hydroxylation and subsequent oxidation to the proposed carcinogenic product dialkylbenzoquinone imine. The current study extends our earlier studies with alachlor and demonstrates that rat liver microsomes metabolize acetochlor and metolachlor to CMEPA (0.065 nmol/min/mg and 0.0133 nmol/min/mg, respectively), whereas human liver microsomes can metabolize only acetochlor to CMEPA (0.023 nmol/min/mg). Butachlor is metabolized to CDEPA to a much greater extent by rat liver microsomes (0.045 nmol/min/mg) than by human liver microsomes (< 0.001 nmol/min/mg). We have determined that both rat and human livers metabolize both CMEPA to MEA (0.308 nmol/min/mg and 0.541 nmol/min/mg, respectively) and CDEPA to DEA (0.350 nmol/min/mg and 0.841 nmol/min/mg, respectively). We have shown that both rat and human liver microsomes metabolize MEA (0.035 nmol/min/mg and 0.069 nmol/min/mg, respectively) and DEA (0.041 nmol/min/mg and 0.040 nmol/min/mg, respectively). We have also shown that the cytochrome P450 isoforms responsible for human metabolism of acetochlor, butachlor, and metolachlor are CYP3A4 and CYP2B6.

In vitro metabolism of alachlor by human liver microsomes and human cytochrome P450 isoforms.

Alachlor (2-chloro-N-methoxymethyl-N-(2,6-diethylphenyl)acetamide) is a widely used pre-emergent chloroacetanilide herbicide which has been classified by the USEPA as a probable human carcinogen. The putative carcinogenic metabolite, 2,6-diethylbenzoquinone imine (DEBQI), is formed through a complex series of oxidative and non-oxidative steps which have been characterized in rats, mice, and monkeys but not in humans. A key metabolite leading to the formation of DEBQI is 2-chloro-N-(2,6-diethylphenyl)acetamide (CDEPA). This study demonstrates that male human liver microsomes are able to metabolize alachlor to CDEPA. The rate of CDEPA formation for human liver microsomes (0.0031 +/- 0.0007 nmol/min per mg) is significantly less than the rates of CDEPA formation for rat liver microsomes (0.0353+/-0.0036 nmol/min per mg) or mouse liver microsomes (0.0106 +/- 0.0007). Further, we have screened human cytochrome P450 isoforms 1A1, 1A2, 2B6, 2C8, 2C9, 2C18, 2C19, 2D6, 2E1, and 3A4 and determined that human CYP 3A4 is responsible for metabolism of alachlor to CDEPA. Further work is necessary to determine the extent to which humans are able to metabolize CDEPA through subsequent metabolic steps leading to the formation of DEBQI.

Cloning and expression of a novel juvenile hormone-metabolizing epoxide hydrolase during larval-pupal metamorphosis of the cabbage looper, Trichoplusia ni.

A full-length cDNA encoding for a microsomal juvenile hormone (JH)-metabolizing epoxide hydrolase (TmEH-1) was isolated from a cDNA library constructed from fat body of last stadium (wandering) cabbage loopers, Trichoplusia ni, at the exact developmental time of maximum JH epoxide hydrolase activity. TmEH-1 was 1887 base pairs in length with a 1389 base pair open reading frame encoding 463 amino acids. Amino acid sequence analysis showed that TmEH-1 was most similar to and contained the exact catalytic triad (Asp-226, Glu-403 and His-430) found in microsomal epoxide hydrolases. TmEH-1-specific message was present along with JH III epoxide hydrolase activity in fat body in feeding (days 1 and 2) and wandering (day 3) larvae with the peak in message level preceding the peak in JH epoxide hydrolase activity by 1 day. When TmEH-1 was expressed in baculovirus-infected Spodoptera frugiperda cells, a 46,000 molecular weight protein appeared on SDS-PAGE which corresponded to the predicted size coded by the TmEH-1 message and which was positively correlated with increases in JH III epoxide hydrolase activity above that of wild-type controls. In subcellular distribution studies, 58% of the juvenile hormone III epoxide hydrolase activity was in the insoluble fractions. Baculovirus expressed TmEH-1 demonstrated a higher specific activity for JH III as compared to the general EH substrates, cis- and trans-stilbene oxide. Southern blot analyses suggested that multiple epoxide hydrolase genes are present in T. ni.

Biological Suppression of Seedborne Fusarium spp. During Cold Stratification of Douglas Fir Seeds.

Fusarium spp. are important soil- and seedborne pathogens of Douglas fir (Pseudotsuga menziesii) in conifer seedling nurseries. We investigated the effects of culture media and cold stratification on isolation of Fusarium spp. from three Douglas fir seedlots and tested whether the numbers and species mixtures found on stratified seeds could cause disease. Nearly all cold-stratified seeds plated on three semiselective culture media yielded Fusarium spp., including F. avenaceum, F. culmorum, F. lateritium, F. moniliforme, F. poae, F. proliferatum, F. sambucinum, F. solani, and F. tricinctum. Species composition did not differ significantly among the media. Isolation of Fusarium spp. from seeds plated on Komada's medium (pH 6.8) at various stages of imbibition and cold stratification progressively increased from 10 to 22% to 65 to 100%. When stratified seeds were planted in conditions conducive to disease development, however, little disease attributable to Fusarium spp. resulted. A subsequent study was conducted to determine whether a biological control agent applied during imbibition could reduce the proliferation of Fusarium spp. during stratification. Unstratified Douglas fir seeds were imbibed for 24 h in a suspension of Pseudomonas chlororaphis isolate RD31-3A, a rifampicin-resistant fluorescent pseudomonad with previously demonstrated biocontrol activity against F. oxysporum. This treatment reduced the proliferation of Fusarium spp. during cold stratification without significantly affecting subsequent seed germination. The greatest reduction in poststratification populations of seedborne Fusarium spp. was achieved when preimbibition treatment with hydrogen peroxide was followed by seed imbibition in live bacteria. Seed imbibition in bacterial suspensions may be an effective means to deliver biological control agents to Douglas fir seeds.

Influence of ectomycorrhizal fungal inoculation on growth and root IAA concentrations of transplanted conifers.

We determined whether in vitro plant growth regulator production by mycorrhizal fungi is correlated with conifer seedling growth and root IAA concentrations. Container-grown seedlings of interior Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), lodgepole pine (Pinus contorta Dougl.) and ponderosa pine (Pinus ponderosa Dougl.) were inoculated at seeding with ectomycorrhizal fungi having a high, moderate or low capacity to produce either IAA or ethylene in vitro. Inoculated seedlings were grown for one season in the nursery, harvested in December, cold stored over winter and then transplanted to either a nursery field or a forest site in the spring. Seedling morphology and endogenous IAA in roots were measured immediately after cold storage and again six and 12 months after transplanting. Morphological responses to inoculation varied among different mycorrhizal fungi. Free IAA concentration of roots was increased in some inoculation treatments for all conifer species. In seedlings transplanted to a nursery field, in vitro ethylene-producing capacity of the ectomycorrhizal fungi was highly correlated with more morphological features than in vitro IAA-producing capacity. Both IAA- and ethylene-producing capacity were significantly correlated with more morphological features in seedlings transplanted to a forest site than in seedings transplanted to a nursery field. One year after transplanting, only in vitro IAA-producing capacity was correlated with endogenous IAA concentration of roots of the inoculated seedlings. We conclude that growth responses of conifer seedlings can be partially influenced by IAA and ethylene produced by ectomycorrhizal fungal symbionts.

Mechanism of action and cloning of epoxide hydrolase from the cabbage looper, Trichoplusia ni.

The majority of the JH III epoxide hydrolase activity in last stadium day 3 (gate 1) wandering Trichoplusia ni was membrane bound with approximately 9% of the activity found in the cytosol. Both the microsomal and cytosolic JH epoxide hydrolases were stable, retaining 30% of their original activity after incubation at 4 degrees C for 15 days. 18O-labeled water underwent enzyme catalyzed regioselective addition to the least substituted C10 position of JH III. In multiple turnover reactions with JH epoxide hydrolase in 97.9% 18O-labeled water, only 91.3% 18O incorporation was observed. This is consistent with an SN2 reaction likely involving a carboxylate in the active site of JH epoxide hydrolase. The DNA amplification cloning of a fragment of a putative T. ni epoxide hydrolase is reported. The deduced amino acid sequence shares 67% similarity to the rat microsomal epoxide hydrolase.

Alpha,beta-unsaturated carbonyl compounds: inhibition of rat liver glutathione S-transferase isozymes and chemical reaction with reduced glutathione.

Five different alpha,beta-unsaturated carbonyl compounds displayed different reactivities with regard to inhibition of alpha- and mu-class isozymes of rat liver glutathione S-transferases and the chemical reaction with glutathione. Only (E)-2-octenal and (E)-3-nonen-2-one exhibited significant levels of inhibition for each of the rat liver GST isozymes examined. The (E)-2-octenal was more effective as an inhibitor of the alpha-class of isozymes when compared to the mu-class, whereas the (E)-3-nonen-2-one showed a greater degree of inhibition of the mu-class of isozymes relative to the alpha-class. Isozyme 1-1 demonstrated the greatest degree of inhibition with (E)-2-octenal (IC50 = 5.89 microM) of all inhibitor/isozyme combinations. The Ki values for (E)-2-octenal and (E)-3-nonen-2-one toward selected alpha- and mu-class of rat liver glutathione S-transferase isozymes were determined and both of these compounds competitively inhibited all five of the rat liver glutathione S-transferase isozymes examined. The Ki values obtained for these two compounds were significantly different for each of the isozymes except for isozyme 4-4. With the alpha-class of rat liver GST isozymes, (E)-3-nonen-2-one showed a larger Ki value than (E)-2-octenal. Whereas, with the mu-class, (E)-2-octenal exhibited a larger Ki value than (E)-3-nonen-2-one. The rate constants of the forward reaction (k+1), as well as the equilibrium constants (Kd) were determined and the rate constants of the reverse reaction (k-1) were calculated.