Amplitude Apodizers Encoded onto Fresnel Lenses Implemented on a Phase-Only Spatial Light Modulator

We show that both a lens and a nonuniform amplitude transmission filter can be encoded simultaneously onto a twisted nematic liquid-crystal spatial light modulator (SLM) working in the phase-only mode. The inherent equivalent apodization that is due to the pixelated structure of the SLM is compensated for. In addition, different types of nonuniform transmission pupil such as transverse apodizing, transverse hyperresolving, and axial hyperresolving (multifocusing) filters are implemented. The excellent agreement between numerical and experimental results shows the capability of this method to encode amplitude apodizers on a phase-only SLM.

Functional recovery of skilled forelimb use in rats obliged to use the impaired limb after grafting of the frontal cortex lesion with homotopic fetal cortex

The long-term effect of transplanting embryonic frontal cortex into a unilateral frontal cortex lesion has been studied in adult rats. Before surgery, activity in an open field, muscular strength of both forelimbs, and performance in a paw-reaching-for-food task were scored in 26 rats. In 21 animals a unilateral cortex lesion was then made in the forelimb motor area of the hemisphere contralateral to the preferred paw in the paw-reaching-for-food task, while the other 5 animals were sham-operated. On retesting, the lesion animals changed the preferred paw. A solid homotopic transplant of embryonic tissue (embryonic day 17) was then placed in the lesion cavity in 11 of the lesion rats. Three months later neither lesion alone nor lesion plus transplantation affected open field behavior and muscular strength, but the lesion permanently affected performance in the paw-reaching-for-food task, as shown by a change of preferred paw and a functional deficit in the paw contralateral to the lesion. Transplantation ameliorated the deficits caused by the lesion, but this was only evident when animals were forced to reach with the paw contralateral to the lesion plus transplant. The behavioral results were independent of the size of the lesion and graft. Connections between graft and host tissue were studied by means of the fluorescent tracer 1,1'-dioctadecyl-3,3,3'3'-tetramethylindocarbocyanine perchlorate (DiI). A dense array of labeled fibers was found in the host cortex adjacent to the transplant. The results suggest that functional recovery depends on grafting but is only evident when the animal is obliged to use the affected limb.

Chromosomal comparisons among and within populations of Simulium (Chirostilbia) pertinax (Diptera, Simuliidae)

Chromosomal studies were carried on six larval populations of Simulium (Chirostilbia) pertinax from different locations in Brazil. Larvae were collected in the states of Paraná, Rio Grande do Sul, Rio de Janeiro and São Paulo. Polytene chromosome map comparisons within and among populations showed no differences in banding pattern, except for some limited polymorphism (secondary NOR and four band polymorphisms). There were no chromosomal variations associated with the resistance or susceptibility of the larvae to temephos. The chromosomal homosequentiality found among the six populations suggests that S. pertinax may be a monomorphic species.

LUMO energy of model compounds of bispyridinium compounds as an index for the inhibition of choline kinase

Eleven derivatives of 1,1'-[1,2-ethylenebis(benzene-1,4-diylmethylene)]bis(4-pyridinium) dibromides bearing various groups at C-4 of the pyridinium moiety were synthesized and examined for their inhibition of choline kinase (ChoK) and antiproliferative activities. The C-4 substituents include electron-releasing, neutral or electron-withdrawing groups. A one-parameter regression equation has been derived which satisfactorily describes the ex vivo inhibitory potency of ChoK of the title compounds. The electronic effect plays a critical function in the ex vivo inhibition of ChoK although the role of electrostatic interactions could be altered due to a solvation process of both ChoK and ligands.

Differential interleukin-8 response of intestinal epithelial cell line to reactogenic and nonreactogenic candidate vaccine strains of Vibrio cholerae

In this study, we analyzed whether attachment of Vibrio cholerae vaccine strains to human intestinal epithelial cells can induce an interleukin-8 (IL-8) response. The IL-8 transcripts were detected by PCR amplification of reverse-transcribed mRNA, and the gene product secretion was measured by an enzyme-linked immunosorbent assay. Infection of monolayers of the undifferentiated HT29-18N2 cell line with reactogenic (JBK70 and 81) and nonreactogenic (CVD103HgR and 638) vaccine strains of V. cholerae resulted in markedly higher IL-8 expression by epithelial cells exposed to reactogenic strains than by cells exposed to the nonreactogenic strains. Additionally, epithelial cells produced IL-8 transcripts following stimulation with cholera vaccine strains in a concentration-dependent manner. These results represent a new insight into the inflammatory component of reactogenicity and could be used as a predictive marker of vaccine reactogenicity prior to human testing.

Optimal multichannel estimation of the location of a target with nonoverlapping noise

We propose a new algorithm for estimating the location of an object in multichannel images when the noise is spatially disjointed from (nonoverlapping with) the target. This algorithm is optimal for nonoverlapping noise and for multichannel images in the maximum-likelihood sense. We consider the case in which the statistical parameters of the input scene are unknown and are estimated by observation. We assess the results for simulated images with white and Gaussian background, for a large scale of variances of the background noise, and different values of the contrast in the scene. We compare the results of this algorithm with the results obtained with two other algorithms, the optimal algorithm for monochannel nonoverlapping noise and the optimal algorithm for multichannel additive noise, and we show that in both cases improvement can be obtained. We show the efficiency of the estimation for real input scenes when the background noise is correlated clutter noise. This algorithm has the same complexity as correlation, and the improvement is obtained with no more calculation cost than with classic methods.

From a classic approach in cancer chemotherapy towards differentiation therapy: acyclic and cyclic seven-membered 5-fluorouracil O,N-acetals

Novel derivatives of 5-fluorouracil (5-FU) possessing a broader spectrum of antitumor activity and fewer toxic side effects than 5-FU have been sought. Herein, we report three different types of 5-FU O,N-acetals: a) a novel class of 5-fluorouracil-containing acyclonucleosides. The antitumor activities of such compounds were assessed against HEp human cells showing that (RS)-1-¿[3-(2-hydroxyethoxy)-1-cyclopentoxy]propyl¿-5-fluorouracil 3c is 4-fold more active than 5-FU. (RS)-1-¿[3-(2-hydroxyethoxy)-1-isopropoxy]propyl¿-5-fluorouracil 3b has important potential advantages over 5-FU because of its lower toxicity and its ability to induce myogenic differentiation in rhabdomyosarcoma cells. Our results suggest that this drug may be useful for differentiation therapy in this type of tumor; b) within the cyclic prodrugs of 5-FU, a series of new ring-expanded isosteres (1,4-oxaheteroepanes) of Ftorafur were synthesized. The level of diastereoselectivity in the preparation of cis and trans 1-(3-chloromethyl)-1,4-dioxepan-5-yl)-5-fluorouracil, although modest, suggests a potentially general approach for controlling the stereochemistry of this unexplored class of reactions involving the preparation of 5-FU seven-membered O,N-acetals; c) new 5-FU acyclic analogs containing two 5-FU moieties at both ends of the molecules with a linker having two amide bonds have been designed and synthesized. These bis(5-FU-O,N-acetals) show interesting antineoplastic activities against the HT-29 cell line.

Fully complex synthetic discriminant functions written onto phase-only modulators

Synthetic discriminant functions (SDF's) are an effective tool for pattern-recognition applications. However, their experimental implementation is difficult because of the difficulty in writing full complex modulation functions onto spatial light modulators (SLM's) with restricted coding domains. Iterative methods are required for the implementation of SDF filters in real SLM's. A great deal of experimental research has been done with phase-only filters because they can be successfully implemented with liquid-crystal SLM's. We have recently introduced a technique for encoding arbitrary amplitude information onto the phase-only filter, thus allowing us to encode an arbitrary complex function onto a phase-only SLM. We apply this technique to the generation of arbitrary complex SDF filters, thus avoiding the necessity of iterative algorithms. We examine the discrimination capabilities of fully complex SDF filters designed with different parameters and constraints. Experimental results obtained with liquid-crystal SLM's are included.

Inherent apodization of lenses encoded on liquid-crystal spatial light modulators

Focusing diffractive optical elements encoded in liquid-crystal spatial light modulators yields an inherent equivalent apodization of the focused spot as a result of the pixelated nature of these devices and the finite extent of each pixel. We present a theoretical explanation for and experimental evidence of this effect. We demonstrate an experimental procedure for measuring the apodization and a method to compensate for this effect.

Construction and characterization of a nonproliferative El Tor cholera vaccine candidate derived from strain 638

In recent clinical assays, our cholera vaccine candidate strain, Vibrio cholerae 638 El Tor Ogawa, was well tolerated and immunogenic in Cuban volunteers. In this work we describe the construction of 638T, a thymidine auxotrophic version of improved environmental biosafety. In so doing, the thyA gene from V. cholerae was cloned, sequenced, mutated in vitro, and used to replace the wild-type allele. Except for its dependence on thymidine for growth in minimal medium, 638T is essentially indistinguishable from 638 in the rate of growth and morphology in complete medium. The two strains showed equivalent phenotypes with regard to motility, expression of the celA marker, colonization capacity in the infant mouse cholera model, and immunogenicity in the adult rabbit cholera model. However, the ability of this new strain to survive environmental starvation was limited with respect to that of 638. Taken together, these results suggest that this live, attenuated, but nonproliferative strain is a new, promising cholera vaccine candidate.

[Meningitis due to haemophilus influenzae type f]

We report an immunocompetent 5-month-old boy with Haemophilus influenzae type f (Hif) meningitis. The patient had previously been immunized with two doses of Hib conjugate vaccine (PRP-T). Vaccination failure was initially suspected based on Gram stain report. The results of culture identified a non-b Haemophilus influenzae capsular serotype (Hif).Non-Hib serotypes should be considered as potential pathogenic agents in children under the age of 5 years with invasive diseases. An adequate epidemiological surveillance system would be helpful in detecting the role of these non-b Hif serotypes as significant pathogens, which appear to be on the increase.

Construction of a cassette for cloning and analysis of replicons

The aim of this work was the construction of a cassette, i.e., a non-replicative molecule formed by linkage of an antibiotic resistance gene and a multiple cloning site. This cassette would allow the cloning and analysis of a wide range of replicons. The aac(6')-lc amikacin gene was isolated and ligated to the multiple cloning site of the pUC18 vector. This construction was HindIII digested and cloned in the HindIII site of the vector. The resulting pHJ13 clone conferred to the recipient cells the ability to grow in presence of amikacin (cassette marker) and ampicillin (vector gene). By restriction analysis, the cassette orientation was established. Cassette versatility is provided by the presence of the unaltered multiple cloning site segment, and also because it allows sequencing of any replication origin inserted. Cassette functionality was demonstrated by ligation to a replicative region of H plasmid pHH1457. Presence of the ori region from pHH1457 and the aac(6')-lc gene was confirmed in E. coli transformed clones. The incompatibility properties of the pHH1457 and its capability to replicate in a Poll defective strain were preserved in the pHJII14 construct. Currently, the amikacin cassette is being used in the characterization of H Complex plasmids.

Glutaryl-CoA dehydrogenase deficiency in Spain: evidence of two groups of patients, genetically, and biochemically distinct

Glutaryl-CoA dehydrogenase (GCDH) deficiency causes glutaric aciduria type I (GA I), an inborn error of metabolism that is characterized clinically by dystonia and dyskinesia and pathologically by neural degeneration of the caudate and putamen. Studies of metabolite excretion allowed us to categorize 43 GA I Spanish patients into two groups: group 1 (26 patients), those presenting with high excretion of both glutarate and 3-hydroxyglutarate, and group 2 (17 patients), those who might not be detected by routine urine organic acid analysis because glutarate might be normal and 3-hydroxyglutarate only slightly higher than controls. Single-strand conformation polymorphism (SSCP) screening and sequence analysis of the 11 exons and the corresponding intron boundaries of the GCDH gene allowed us to identify 13 novel and 10 previously described mutations. The most frequent mutations in group 1 were A293T and R402W with an allele frequency of 30% and 28%, respectively. These two mutations were also found in group 2, but always in heterozygosity, in particular in combination with mutations V400M or R227P. Interestingly, mutations V400M and R227P were only found in group 2, and at least one of these mutations was found in 11 of 15 unrelated alleles, accounting together for 53% of the mutant alleles in group 2. Therefore, it seems clear that two genetically and biochemically distinct groups of patients exist. The severity of the clinical phenotype seems to be closely linked to the development of encephalopathic crises rather than to residual enzyme activity or genotype. Comparison of GCDH protein with other acyl-CoA dehydrogenases (whose x-ray crystal structure has been determined) reveals that most of the mutations identified in GCDH protein seem to affect folding and tetramerization, as has been described for a number of mutations affecting mitochondrial beta-oxidation acyl-CoA dehydrogenases.

Modulation of myogenic differentiation in a human rhabdomyosarcoma cell line by a new derivative of 5-fluorouracil (QF-3602)

The in vitro study of mechanisms involved in drug-induced maturation has made it possible to use differentiation-based therapy in clinical practice. The goal of this new therapy is the development of specific agents to induce cancer cells to stop proliferating and express characteristics of normal cells. Recently, by structural modifications of 5-fluorouracil (5-FU), we synthesized a new pyrimidine acyclonucleoside-like compound, 1-¿[3-(3-chloro-2-hydroxypropoxy)-1-methoxy]propyl¿-5-fluorouracil (QF-3602), which showed in rhabdomyosarcoma cells a low toxicity and time-dependent growth inhibition. In this work, we compared the degree of myogenic differentiation of RD rhabdomyosarcoma (RMS) cells after treatment with QF-3602 and 5-FU. Scanning and transmission electron microscopy (SEM and TEM) and immunocytochemical analyses showed that QF-3602 induced the appearance of myofilaments along the myotube-like giant RD cells, an increase in fibronectin and a decrease in vimentin expression. In contrast, only minor changes were observed with 5-FU. Moreover, polymerase chain reaction (PCR) analyses showed that QF-3602 did not induce overexpression of the mdr 1 gene, a resistance mechanism that frequently appears in classical cytotoxic therapy in these tumors. Compounds obtained by structural modifications of 5-FU may be useful in differentiation therapy as a new approach to the treatment of RMS.

Hydroacoustic estimation of fish biomass in the Gulf of Nicoya, Costa Rica

A stratified sampling design was used for a hydroacoustic survey of the inner parts of the Gulf of Nicoya in 1987 and 1988. The bottom topography of the inner Gulf was modeled by introducing the concept of a topographical basin model, as the basis for the projection of the sample survey estimates to the entire inner gulf. The bottom depth contours and volumes for the basin model were constructed from nautical charts. The estimates of sample abundance were made for the fish in the inner Gulf using the acoustic methods, EMS (Expectation Maximization and Smoothing) and echo integration. The estimates of population were made by the multiplication of the topographic model's estimate of water volume and a model of fish density dependent on bottom depth. The results showed a general decrease in fish density biomass with bottom depth, and a simultaneous tendency for maximum concentrations over bottom depths of about four meters. The four meter bottom depth includes a broad expanse of the inner Gulf located south of Isla Chira. Overall estimates of volumetric density (0.269 fish/m3) and of areal densities (1.88 fish/m2) are comparable to other estuarine shallow water environments.

[Spatial distribution of sharks captures in the Pacific of Nicaragua and its relationship with several oceanographic variables]

Between August 1995 and August 1997 long line fishing techniques and a bathythermograph were used to correlate some physical variables with the spatial distribution of four shark species in 26 fishing cruises off the Nicaraguan Pacific Coast. They were the thresher (Alopias vulpinus), blue (Prionace glaucea), gray (Carcharhinus falciformis) and hammer (Sphyra lewini). All species concentrated in the southeastern Nicaraguan Pacific, at the seasonal upwelling area of Papagayo Gulf. The range of sea surface temperatures in which the sharks were captured was 25-28 degrees C. We could clearly associate this physical parameter with shark availability. The vertical distribution of the captured sharks suggests that they occupy termocline levels above the 15 degrees C isotherm. Although these species are oceanic, the blue shark was captured in ocean waters over the 1800 m isobar, while the grey and thresher sharks where close to the continental shelf. Body length in decreasing order are: thresher (210-290 cm, SN = 21), blue (60-240 cm, SN = 13) and gray (80-200 cm, SN = 17).

QSAR of 1,1'-(1,2-ethylenebisbenzyl)bis(4-substitutedpyridinium) dibromides as choline kinase inhibitors: a different approach for antiproliferative drug design

Ten new structures of a series of the title compounds were synthesized and screened for their activity to inhibit choline kinase under ex vivo conditions. Their inhibitory potency correlates with the 13C chemical shifts (in CD3OD) of the methylene group bearing the positively charged nitrogen. The inhibitory effect on proliferation against the HT-29 cell line is strongly dependent on its ability to inhibit the production of phosphorylcholine.

Serum leptin concentrations in children with Prader-Willi syndrome and non-syndromal obesity

There is limited information on the underlying physiological mechanisms promoting obesity in patients with Prader-Willi syndrome (PWS). The aim of this study was to investigate whether body fat regulation in children with PWS is similar to that in children with non-syndromal obesity and non-obese children. We studied three groups: 1) 72 non-obese children and adolescents; 2) 68 children with non-syndromal obesity; and 3) 11 patients with PWS. Height and weight were measured and body mass index (BMI) and BMI SDS were calculated. Fasting serum leptin concentrations were determined. Median leptin serum concentrations were similar in PWS patients and children with non-syndromal obesity. Median leptin serum concentrations were higher in these two groups than in the non-obese group. Log leptin serum concentrations and BMI SDS showed significant correlations in the three groups of patients; correlation coefficients were 0.525, 0.285 and 0.854, respectively. In conclusion, median leptin serum concentrations are similar in PWS patients and children with non-syndromal obesity. The relationship between log serum leptin concentrations and BMI SDS was different in the three groups of patients studied.

Gray-level computer-generated hologram filters for multiple-object correlation

Synthesis of gray-level computer-generated holograms allows for an increase of the information storage capability that is usually achieved with conventional binary filters. This is mainly because more degrees of freedom are available. We propose to profit from this feature by synthesizing complex filters formed by many superimposed holograms, each with a different carrier frequency. We apply these gray-level filters to perform multichannel correlation and in this way enhance the capability of optical correlators to process the information in parallel and simultaneously. First, we analyze the behavior of some performance criteria on the impulse response and on the correlation as a function of the number of holograms that are multiplexed. Then we show the results of two experiments: In the first a composed phase-only filter is used in a multiple-object recognition process. In the second a composed synthetic discriminant function filter is used to implement an object classification by means of a binary code.

Image processing with the radial Hilbert transform: theory and experiments

The Hilbert transform is useful for image processing because it can select which edges of an input image are enhanced and to what degree the edge enhancement occurs. However, the transform operation is one dimensional and is not applicable for arbitrarily shaped two-dimensional objects. We introduce a radially symmetric Hilbert transform that permits two-dimensional edge enhancement. We implement one-dimensional, two-dimensional, and radial Hilbert transforms with a programmable phase-only liquid-crystal spatial light modulator. Experimental results are presented.