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.

Bessel function output from an optical correlator with a phase-only encoded inverse filter

We report on a technique for producing a Bessel function correlation output for an arbitrary input pattern. The central dark spot at the center of the Bessel function correlator output is narrower than the width of the normal correlation spot and can be extremely useful for locating the center of the correlation signal. The Bessel function is produced by convolution of the extremely sharp correlation produced by an inverse filter with the Bessel function and is encoded with a single phase-only liquid-crystal spatial light modulator. To encode amplitude information on the filter, we spatially modulate the phase encoded on the filter. Amplitude modulation is obtained by modulation of the diffraction efficiency of the phase grating. Experimental results are presented.

Cloning and characterization of a replicon region of the IncHII plasmid pHH1457

A replicative region of the large conjugative plasmid pHH1457 (incompatibility group HII (IncHII)) was cloned. A 1.4-kbp region, in a stable pSBII14 clone, containing a PolI-independent replicon and determinants for the HII incompatibility phenotype, was selected and characterized. High incompatibility with IncHII plasmids was corroborated. Independent replication of the insert was demonstrated by ligation to an antibiotic resistance cassette. pSBII14 was used as a probe to identify IncHII plasmids from other members of the H complex: IncHI (IncHI1, IncHI2 and IncHI3 subgroups). Hybridization experiments revealed a high homology with the replication region of IncHII plasmids, but not with IncHI1 or IncHI3 plasmid prototypes. Homology with IncHI2 plasmids was observed, suggesting the presence of IncHII-like replicons among this subgroup of plasmids. This is the first report of the characterization of an IncHII plasmid maintenance region.

Encoding amplitude information onto phase-only filters

We report a new, to our knowledge, technique for encoding amplitude information onto a phase-only filter with a single liquid-crystal spatial light modulator. In our approach we spatially modulate the phase that is encoded onto the filter and, consequently, spatially modify the diffraction efficiency of the filter. Light that is not diffracted into the first order is sent into the zero order, effectively allowing for amplitude modulation of either the first-order or the zero-order diffracted light. This technique has several applications in both optical pattern recognition and image processing, including amplitude modulation and inverse filters. Experimental results are included for the new technique.

Programmable axial apodizing and hyperresolving amplitude filters with a liquid-crystal spatial light modulator

Amplitude-transmitting filters for apodizing and hyperresolving applications can be easily implemented by use of a two-dimensional programmable liquid-crystal spatial light modulator operating in a transmission-only mode. Experimental results are in excellent agreement with theoretical predictions. This approach can permit the analysis of various filter designs and can allow the filters to be changed rapidly to modify the response of an optical system.

ENT aspects of the mummification of the head in ancient Egypt: an imaging study

This study of a mummified head from the British museum by high resolution computer tomography and 3D reconstruction illustrates, without mutilation of the specimen, some aspects of mummification of the head; namely the extraction of the brain through the nose and filling the cranium with linen like material, packing of the oral cavity and the presence of false eyes. These findings alone allow one to date the mummy to no sooner than the 20th dynasty, a time when this custom was at its peak. ENT aspects of the mummification of the head are discussed.

[The persistence of the left vena cava superior and the absence of the right vena cava superior: the implications in the implantation of a definitive pacemaker]

Persistent left superior vena cava and associated absence of the right superior vena cava is exceedingly rare. The authors present a case, diagnosed when a DDD pacemaker system was being implanted, and point out its rarity, possibility of diagnosis by non invasive methods and technical implications in transvenous electrode implantation.

Preliminary assessment of the safety and immunogenicity of a new CTXPhi-negative, hemagglutinin/protease-defective El Tor strain as a cholera vaccine candidate

Vibrio cholerae 638 (El Tor, Ogawa), a new CTXPhi-negative hemagglutinin/protease-defective strain that is a cholera vaccine candidate, was examined for safety and immunogenicity in healthy adult volunteers. In a double-blind placebo-controlled study, no significant adverse reactions were observed in volunteers ingesting strain 638. Four volunteers of 42 who ingested strain 638 and 1 of 14 who received placebo experienced loose stools. The strain strongly colonized the human small bowel, as evidenced by its isolation from the stools of 37 of 42 volunteers. V. cholerae 638, at doses ranging from 4 x 10(7) to 2 x 10(9) vibrios, elicited significant serum vibriocidal antibody and anti-Ogawa immunoglobulin A antibody secreting cell responses.

GR-891: a novel 5-fluorouracil acyclonucleoside prodrug for differentiation therapy in rhabdomyosarcoma cells

Differentiation therapy provides an alternative treatment of cancer that overcomes the undesirable effects of classical chemotherapy, i.e. cytotoxicity and resistance to drugs. This new approach to cancer therapy focuses on the development of specific agents designed to selectively engage the process of terminal differentiation, leading to the elimination of tumorigenic cells and recovery of normal cell homeostasis. A series of new anti-cancer pyrimidine acyclonucleoside-like compounds were designed and synthesized by structural modifications of 5-fluorouracil, a drug which causes considerable cell toxicity and morbidity, and we evaluated their applicability for differentiation therapy in human rhabdomyosarcoma cells. We tested the pyrimidine derivative GR-891, (RS)-1-[[3-(2-hydroxyethoxy)-1-isopropoxy]propyl]-5-fluorouracil, an active drug which shows low toxicity in vivo and releases acrolein which is an aldehyde with anti-tumour activity. Both GR-891 and 5-fluorouracil caused time- and dose-dependent growth inhibition in vitro; however, GR-891 showed no cytotoxicity at low doses (22.5 micromol l(-1) and 45 micromol l(-1)) and induced terminal myogenic differentiation in RD cells (a rhabdomyosarcoma cell line) treated for 6 days. Changes in morphological features and in protein organization indicated re-entry in the pathway of muscular maturation. Moreover, GR-891 increased adhesion capability mediated by the expression of fibronectin, and did not induce overexpression of P-glycoprotein, the mdr1 gene product, implicated in multidrug resistance. New acyclonucleoside-like compounds such as GR-891 have important potential advantages over 5-fluorouracil because of their lower toxicity and their ability to induce myogenic differentiation in rhabdomyosarcoma cells. Our results suggest that this drug may be useful for differentiation therapy in this type of tumour.

[Rett's syndrome in the Spanish population]

INTRODUCTION AND OBJECTIVE

Rett syndrome was described in 1966 and became known through the English medical literature in 1983. There are typical and atypical forms. The objective of this study was to record the cases diagnosed in Spain and discover their clinical characteristics in order to describe its phenotype and geographical distribution.

PATIENTS AND METHODS

We know of 207 cases and have obtained the records of 168 of these patients. A protocol and data collection programme has been developed giving the criteria for inclusion, and data which support or exclude this. Data collection was by post and the data for identification were the date of birth and the initials of the name and two surnames. With these variables, double-registering of patients was almost impossible. A statistical study with descriptive analysis and a study of continuous and alternating variables was immediately done.

RESULTS AND CONCLUSION

The results gave the main characteristics, the differences between typical and atypical cases and a comparative study of variables. It has given clinical data which may be useful for prognosis of the condition in the future.

Production of emotional facial expressions in European American, Japanese, and Chinese infants

European American, Japanese, and Chinese 11-month-olds participated in emotion-inducing laboratory procedures. Facial responses were scored with BabyFACS, an anatomically based coding system. Overall, Chinese infants were less expressive than European American and Japanese infants. On measures of smiling and crying, Chinese infants scored lower than European American infants, whereas Japanese infants were similar to the European American infants or fell between the two other groups. Results suggest that differences in expressivity between European American and Chinese infants are more robust than those between European American and Japanese infants and that Chinese and Japanese infants can differ significantly. Cross-cultural differences were also found for some specific brow, cheek, and midface facial actions (e.g., brows lowered). These are discussed in terms of current controversies about infant affective facial expressions.

Input-image homogenization as a method to improve a correlator's discrimination capability

We propose an input-image preprocessing method consisting of homogenization of the image to improve the discrimination capability of a correlation-based recognition process. This method is an approximation of the optimal filter. It offers the advantage that correlation with the preprocessed images can easily be implemented in an optical correlator working with phase-only spatial light modulators.

Replicating function of the RS1 element associated with Vibrio cholerae CTX phi prophage

The RS1 element associated with Vibrio cholerae CTX phi prophage was cloned from an E1 Tor biotype Vibrio cholerae strain. We used the recA- vaccine strain Peru-15, that lacks the target for RS-mediated site-specific integration, to show that RS1 promotes autonomous replication of a suicide vector. A linker insertion in the rstR open reading frame abolished autonomous replication in Peru-15 but not in a strain containing an RS1 in the chromosome. An AT-rich region containing cis-acting elements involved in autonomous replication was identified by deletion. This region was sufficient to support autonomous replication in a strain containing an RS1 in the chromosome. DNA sequence analysis of a region present in RS1 and not RS2 revealed the presence of putative binding sites for host proteins involved in plasmid replication. These results indicate that RS1 contains a replicon distinct from RS2 which could be involved in replicative recombination events associated with tandem amplification of the CTX element.

Production of emotional facial expressions in European American, Japanese, and Chinese infants

European American, Japanese, and Chinese 11-month-olds participated in emotion-inducing laboratory procedures. Facial responses were scored with BabyFACS, an anatomically based coding system. Overall, Chinese infants were less expressive than European American and Japanese infants. On measures of smiling and crying, Chinese infants scored lower than European American infants, whereas Japanese infants were similar to the European American infants or fell between the two other groups. Results suggest that differences in expressivity between European American and Chinese infants are more robust than those between European American and Japanese infants and that Chinese and Japanese infants can differ significantly. Cross-cultural differences were also found for some specific brow, cheek, and midface facial actions (e.g., brows lowered). These are discussed in terms of current controversies about infant affective facial expressions.

One-step multichannel pattern recognition based on the pixelated structure of a spatial light modulator

We present an architecture in which a multichannel correlator can perform simultaneous optical pattern recognition. Processing in parallel is made possible by use of the different diffraction orders produced by the pixelated structure of the liquid-crystal spatial light modulator employed to display the input scene. We codify additional quadratic phases in the filters to separate the correlation information corresponding to each channel. We demonstrate that the system can recognize different targets simultaneously. Good agreement between experimental and numerically simulated results is obtained.

Production and characterization of a monoclonal antibody against mannose-sensitive hemagglutinin of Vibrio cholerae

We have generated murine monoclonal antibodies (MAb) against Vibrio cholerae mannose-sensitive hemagglutinin (MSHA) using conventional hybridoma procedures. Seven hybridomas were obtained and one characterized. Hybridoma 2F12/F1 secreted an antibody of the IgG3 type that reacted with a 17-kDa antigen corresponding to the product of the mshA gene. This MAb inhibited mannose-sensitive agglutination of chicken erythrocytes by EL tor and O139 vibrios. Vibrios expressing MSHA activity inhibited binding of the antibody secreted by 2F12/F1 to MSHA-coated microtiter plates.

Detection theory approach to multichannel pattern location

We propose and assess new algorithms for detecting and locating an object in multichannel images. These algorithms are optimal for additive Gaussian noise and maximize the likelihood of the observed images. We consider two cases, in which the illumination of the target and the variance of the noise in each channel are either known or unknown. We show that in the latter case the algorithm provides accurate estimates of variance and luminance. These algorithms can be viewed as postprocessed versions of the correlation of a reference with the scene image in each channel.

Choline kinase inhibitors as a novel approach for antiproliferative drug design

Recent progress in deciphering the molecular basis of carcinogenesis is of utmost importance to the development of new anticancer strategies. To this end, it is essential to understand the regulation of both normal cell proliferation and its alterations in cancer cells. We have previously demonstrated that in ras-transformed cells there is an increased level of phosphorylcholine (PCho) resulting from a constitutive activation on choiline kinase (ChoK). The importance of ChoK for the regulation of cell proliferation has also been proposed since an inhibitor for this enzyme, hemicholinium-3 (HC-3), drastically reduces entry into the S phase after stimulation with growth factors. Here we report the synthesis of several new compounds which are highly specific inhibitors for ChoK, with up to 1000-fold or 600-fold increased inhibitory activity, compared to HC-3 under ex vivo or in vitro conditions respectively. These novel compounds also drastically reduce entry into the S phase after stimulation with specific growth factors. A more profound inhibition of cell proliferation was observed in ras-, src- and mos-transformed cells in the presence of ChoK inhibitors, compared to their parental, untransformed NIH3T3 cells. By contrast, this effect was not observed in fos-transformed cells. While ras, src and mos transformation is associated with elevated levels of ChoK activity, fos-induced transformation does not affect ChoK activity. The inhibitory effect on proliferation of the new compounds correlates with their ability to inhibit the production of phosphorylcholine in whole cells, a proposed novel second messenger for cell proliferation. These results strongly support a critical role of choline kinase in the regulation of cell growth and makes this enzyme a novel target for the design of new antiproliferative and anticancer drugs.

Real-time binary-amplitude phase-only filters

A real-time binary-amplitude phase-only filter (BAPOF) implemented in available phase-only modulators is presented. The BAPOF has an amplitude transmission equal to one only in a region of support, while the transmission is equal to zero in the complementary region. To implement zero transmission in a phase-only modulator we propose to add a linear phase to the region of support. In this way the correlation desired is obtained off axis. Computer simulations and experimental results obtained with this technique are given.

Enterocutaneous fistulas: an unusual solution

Enterocutaneous fistulas are not a minor problem in gastrointestinal tract surgery. Significant reduction of mortality and morbidity has been attained but they still remain high. The authors report three clinical cases in which they sealed and treated enterocutaneous, chronic, iatrogenic fistulas by injecting biological glue (N-Butil 2-Cyanoacrylate-Histoacryl) into the internal opening and fistulous tract. We believe that the technic we propose here, in the proper setting, may be an important contribution to the management of iatrogenic (postoperative) enterocutaneous fistulas.

Diheterocyclanes as synthons for the preparation of novel series of nucleoside and acyclonucleoside analogues

Convenient synthesis of 1-[[3-(2-hydroxyethylhetero)-1-alkoxy]alkyl]-5-fluorouracils 3-8 was accomplished via the use of tin (IV) chloride, capable of a 1,4-chelation on alkoxy-1,4-diheteroepanes. Increasing the reaction time led to 5-FU seven-membered nucleoside analogues which could be considered as upper isosteres of the effective antitumour agent Ftorafur. Using 1-[[3-(2-hydroxyethoxy)-1-alkoxy]propyl]-5-fluorouracil as a parent drug, several chemical modifications on the acyclic moiety were made with the aim of obtaining new compounds showing significant antiproliferative activity in rhabdomyosarcoma (RD) cells. 14 treatment in vitro caused time- and dose-dependent growth inhibition on RD cells. Interestingly, when they were treated with doses of 35 microM and 140 microM of 14 for 6 days, they showed morphological and phetotypic differentiation with increased expression of desmin, alpha-actinin and tropomyosin. We suggest a potential role for differentiation therapy as a therapeutic approach to the treatment of rhabdomyosarcoma.

Promoter activities in Vibrio cholerae ctx phi prophage

Comparison of cholera toxin (CT) production directed by different gene constructs and S1 nuclease mapping revealed the presence of a ctxB-specific promoter within the ctxA coding sequence. Initiation of transcription in this region occurred in wild-type El Tor and classical biotype choleragenic vibrios. We propose that transcription from the ctxB-specific promoter and a stronger ribosomal binding site on the ctxB mRNA synergistically contribute to achieve the correct (5B:1A) subunit stoichiometry. Plasmid pB, a CT promoterless vector expressing only CTB, was used to detect promoter activity by restoration of A-subunit synthesis. Promoter activity expressed in vitro and in vivo was detected upstream of the zonula occludens toxin gene, suggesting that this factor could be produced in vivo to contribute to fluid accumulation. No promoter activity was detected in vitro and in vivo upstream from the accessory cholera enterotoxin gene.

A New Systematization of the Conformational Behavior of Seven-Membered Rings. Isoclinal Anomeric and Related Orientations(1)

The chair and twist-chair conformations of seven-membered rings are classified as a function of the signs of their endocyclic torsion angles. The conformational analysis (MM3) of the methoxy- and methyloxepanes 1-6 used as patterns allows the study and classification of the different types of hydrogen orientation in the seven-membered saturated heterocycles. General principles are established, allowing the prediction of the stability of the different twist-chair conformations as a function of the substituent type, its position in the ring, and the type of hydrogen atom that has been substituted. These results are extended to the 1,4-dioxepane derivatives 7-13 and are compared with experimental data.

Effects on bone mass of long term treatment with thyroid hormones: a meta-analysis

Osteoporosis is the main cause of spine and hip fractures. Morbidity, mortality, and costs arising from hip fractures have been well documented. Thyroid hormones (TH) are widely prescribed, mainly in the elderly. Some studies (but not all) found a deleterious effect of suppressive TH therapy on bone mass. These conflicting data raised a controversy as to the safety of current prescribing and follow-up habits, which, in turn, raised major health-care issues. To look for a detrimental effect on bone of TH therapy, we performed a meta-analysis (by pooling standardized differences, using a fixed effect model) of all published controlled cross-sectional studies (41, including about 1250 patients) concerning the impact of TH therapy on bone mineral density (BMD). Studies with women receiving estrogen therapy were excluded a priori, as were studies with a high percentage of patients with postoperative hypoparathyroidism, when no separate data were available. We decided to stratify the data according to anatomical site, menopausal status, and suppressive or replacement TH therapy, resulting in 25 meta-analysis on 138 homogeneous subsets of data. The main sources of heterogensity between studies that we could identify were replacement or suppressive TH therapy, menopausal status, site (lumbar spine, femoral neck, Ward's triangle, greater trochanter, midshaft and distal radius, with various percentages of cortical bone), and history of hyperthyroidism, which has recently been found to impair bone mass in a large epidemiological survey. To improve homogeneity, we excluded a posteriori 102 patients from 3 studies, who had a past history of hyperthyroidism and separate BMD data, thus allowing assessment of the TH effect in almost all 25 subset meta-analyses. However, controls were usually not matched with cases for many factors influencing bone mass, such as body weight, age at menarche and at menopause, calcium dietary intake, smoking habits, alcohol intake, exercise, etc. For lumbar spine and hip (as for all other sites), suppressive TH therapy was associated with significant bone loss in postmenopausal women (but not in premenopausal women), whereas, conversely, replacement therapy was associated with bone loss in premenopausal women (spine and hip), but not in postmenopausal women. The detrimental effect of TH appeared more marked on cortical bone than on trabecular bone. Only a large long term prospective placebo-controlled trial of TH therapy (e.g. in benign nodules) evaluating BMD (and ideally fracture rate) would provide further insight into these issues.

Long-term persistence of ciprofloxacin-resistant Haemophilus influenzae in patients with cystic fibrosis

Ciprofloxacin has been a major advance in the treatment of chronic respiratory infections. Three patients with cystic fibrosis and colonized by 5 nontypeable Haemophilus influenzae strains exhibiting low- (MIC, 2 microg/mL) and high-level ciprofloxacin resistance (MICs, 16-32 microg/mL) are described. The patients had received several courses of ciprofloxacin. These MICs represent a decrease in ciprofloxacin susceptibility of 200-3200 times. Molecular epidemiologic methods demonstrated that 2 patients were chronically colonized by their own ciprofloxacin-resistant strains for > or = 15-17 months. Three strains showed simultaneous resistance to ampicillin and chloramphenicol by enzyme inactivation, and 2 had ampicillin resistance without beta-lactamase activity. These data suggest that the emergence and long-term persistence of ciprofloxacin-resistant H. influenzae in patients with cystic fibrosis can be a consequence of antibiotic treatment.