Serosurvey for Brucella spp. and Coxiella burnetii in animals on Caribbean islands

To determine the prevalence of antibodies to Brucella melitensis, Brucella abortus and Coxiella burnetii in animals on Caribbean islands we obtained sera from convenience samples of cattle (C), sheep (S), goats (G) and cats (F) from Dominica (C, S, G), Grenada (C, S, G), Montserrat (C, S, G), Puerto Rico (C), Nevis (C, S, G), St Kitts (C, S, G, F) and St Lucia (C, G). The sera were tested for antibodies against the Brucella spp. using commercial ELISA kits. Some sera were also tested at 1/80 for antibodies to C. burnetii using an indirect fluorescent antibody test. Positive sera were also tested at 1/640. None of 599 cattle, 462 sheep or 434 goats were positive in the Brucella ELISAs. None of 230 cattle had antibodies against C. burnetii, but one of 299 sheep was positive at 1/80 (Dominica – 1/54, 2%, 95% CI (0%–5.6%)), as were two of 314 goats, at 1/80 (Grenada – 1/53, 2%, 95% CI (0%–7.5%)) and 1/640 (St Kitts − 1/18, 5.6%, 95% CI (0%–16.7%)), and one of 34 cats, at 1/80 (St Kitts − 1/34; 3%, 95% CI (0%–8.8%)). Our data suggests that there is a very low prevalence or absence of B. melitensis and B. abortus on Caribbean islands. Coxiella burnetii, however, is present but it appears to be present on only some islands and then only at low levels. Overall, there appears to be a low threat to human and animal health from these organisms in the Caribbean.

Improving global integration of crop research

Field laboratories in realistic crop environments are needed

Comprehensive Sclerotinia Stem Rot Screening of Soybean Germplasm Requires Multiple Isolates of Sclerotinia sclerotiorum

Sclerotinia sclerotiorum population variability directly affects Sclerotinia stem rot (SSR) resistance breeding programs. In the north-central United States, however, soybean germplasm selection has often involved only a single isolate. Forty-four S. sclerotiorum isolates from Illinois, Michigan, Minnesota, Nebraska, Wisconsin, Poland, and across 11 different host species were evaluated for variation in isolate in vitro growth, in vitro oxalate production, and in planta aggressiveness on the susceptible soybean 'Williams 82'. Significant differences (P < 0.0001) were detected in isolate in planta aggressiveness, in vitro growth, and in vitro oxalate production. Furthermore, diverse isolate characteristics were observed within all hosts and locations of collection. Aggressiveness was not correlated to colony growth and was only weakly correlated (r = 0.26, P < 0.0001) to isolate oxalate production. In addition, the host or location of collection did not explain isolate aggressiveness. Isolate oxalic acid production, however, may be partially explained by the host (P < 0.05) and location (P < 0.01) of collection. Using a representative subset of nine S. sclerotiorum isolates and soybean genotypes exhibiting susceptible or resistant responses (determined using a single isolate), a significant interaction (P = 0.04) was detected between isolates and genotypes when SSR severity was evaluated. Our findings suggest that screening of S. sclerotiorum-resistant soybean germplasm should be performed with multiple isolates to account for the overall diversity of S. sclerotiorum isolates found throughout the soybean-growing regions of the United States.

Ehrlichiosis, babesiosis, anaplasmosis and hepatozoonosis in dogs from St. Kitts, West Indies

Background

Although tick-borne diseases are important causes of morbidity and mortality in dogs in tropical areas, there is little information on the agents causing these infections in the Caribbean.

Methodology

We used PCRs to test blood from a cross-section of dogs on St Kitts for Ehrlichia (E.) canis, Babesia (B.) spp., Anaplasma (A.) spp. and Hepatozoon (H.) spp. Antibodies against E. canis and A. phagocytophilum/platys were detected using commercial immunochromatography tests. Records of the dogs were examined retrospectively to obtain clinical and laboratory data.

Principal findings

There was serological and/or PCR evidence of infections of dogs with E. canis (27%; 46/170), Babesia spp. (24%; 90/372) including B. canis vogeli (12%; 43/372) and B. gibsoni (10%; 36/372), A. platys (11%; 17/157) and H. canis (6%; 15/266). We could not identify the Babesia sp. detected in nine dogs. There was evidence of multiple infections with dual infections with E. canis and B. canis vogeli (8%; 14/179) or B. gibsoni (7%; 11/170) being the most common. There was agreement between immunochromatography and PCR test results for E. canis for 87% of dogs. Only 13% of exposed dogs had signs of a tick-borne disease and 38% had laboratory abnormalities. All 10 dogs presenting for a recheck after treatment of E. canis with doxycycline were apparently healthy although all remained seropositive and six still had laboratory abnormalities despite an average of two treatments with the most recent being around 12 months previously. Infections with Babesia spp. were also mainly subclinical with only 6% (4/67) showing clinical signs and 13% (9/67) having laboratory abnormalities. Similarly, animals with evidence of infections with A. platys and H. canis were largely apparently healthy with only occasional laboratory abnormalities.

Conclusions

Dogs are commonly infected with tick-borne pathogens in the Caribbean with most having no clinical signs or laboratory abnormalities.

“I Wish I Had AIDS”: A qualitative study on access to health care services for HIV/AIDS and diabetic patients in Cambodia

Financially stricken Cambodian patients with diabetes and HIV/AIDS typically encounter multiple, serious barriers to effective care. This process may extend over many years and involve numerous rounds of diagnosis and treatment as the disease progresses from initial symptoms to longer term complications. Living with both the impact of the disease and this ongoing struggle for care can severely disrupt the everyday life of both sufferers and their families. Our retrospective study adopted qualitative research methods to collect data from HIV/AIDS and diabetic patients enrolled and not enrolled in treatment programs at varying institutions in urban and rural settings. Using purposive sampling techniques, a total of 25 HIV/AIDS and 45 diabetic patients were recruited. Semi-structured and open-ended interviews were used to collect information on patient experiences of different phases in the on-going process of seeking care and treatment. The findings indicate that both HIV/AIDS and diabetic patients encounter multiple supply- and demand-side barriers to care at different stages of their illness. More strikingly, our research findings suggest that supply-side barriers, for example rationing systems or targeting strategies that limit access to free treatment or social assistance, are substantially higher for diabetic patients. This perceived inequity had a profound impact on diabetic patients to the extent that some “wished they had HIV/AIDS”. These findings suggest that there is an urgent need to widen the focus of health care to address the substantial and increasing burden of disease resulting from diabetes and other serious chronic disorders in Cambodia and many other low/middle income countries. 

Protein analysis as a measure of active biomass in activated sludge

Conventional methods to determine the biomass in activated sludge are the measurement of total suspended solids (TSS) and volatile suspended solids (VSS). Such methods do not distinguish between active biomass and inactive organic material. In this study, biomass was determined with both conventional methods and also through measuring the protein content with the modified Lowry method. In order to investigate the relationship between activity and biomass concentration in terms of TSS, VSS and protein content, some starvation experiments were conducted. It was found that the protein fraction of VSS differs under different starvation conditions. The biological activity of the activated sludge was measured as oxygen uptake rate (OUR). The strongest correlation could be measured between protein and OUR under various conditions. The results show that protein is an appropriate parameter for the measurement of the biological activity.

Ehrlichia ruminantium in Amblyomma variegatum and domestic ruminants in the Caribbean

The highly sensitive nested pCS20 polymerase chain reaction assay for Ehrlichia ruminantium was negative on 506 Amblyomma variegatum from Caribbean islands where clinical heartwater has not been reported, mainly the United States Virgin Islands (18), Dominica (170), Montserrat (5), Nevis (34), St. Kitts (262), and St. Lucia (17). Positive results were obtained with positive controls (Crystal Springs strain) and A. variegatum from countries in Africa where infections are endemic, mainly Tanzania (1/37) and Burkino Faso (2/29). Positive major antigenic protein-1 enzyme-linked immunosorbent assays for E. ruminantium were obtained on convenience samples of sera from apparently healthy cattle, sheep, and goats on Dominica (0/95, 0%; 3/135, 2%; 2/57, 4%), Grenada (0/4, 0%; 1/98, 1%; 1/86, 1%), Montserrat (0/12, 0%; 0/28, 2%; 5/139, 4%), Nevis (0/45, 0%; 0/157, 0%; 0/90, 0%), Puerto Rico (0/422, 0%; 0, 0%), St. Kitts (3/86, 4%; 1/25, 0%; 0/26, 0%), and St. Lucia (0/184, 0%; 0/15, 0%; 0, 0%), respectively. The pCS20 polymerase chain reaction results indicate E. ruminantium is not present on islands where clinical heartwater does not occur. The occasional positive major antigenic protein-1B enzyme-linked immunosorbent assay results appear, then, to be false-positive reactions, and serology appears to be of limited use in testing for E. ruminantium in the Caribbean, as is the case in Africa.

Rickettsia africae in Amblyomma variegatum and domestic ruminants on eight Caribbean islands

We used PCRs with omp A primers to determine if spotted fever group rickettsiae occurred in Amblyomma variegatum from 6 Caribbean islands. Positive amplicons were obtained from ticks from the U.S. Virgin Islands (9/18; 50%), Dominica (39/171; 30%), Montserrat (2/5; 40%), Nevis (17/34; 50%), St. Kitts (46/227; 20%), and St. Lucia (1/14; 7%). Sequences for a convenience sample of reaction products obtained from A. variegatum on St. Kitts (7), American Virgin Islands (4), Montserrat (2), and St. Lucia (1) were 100% homologous with that of Rickettsia africae , the agent of African tick-bite fever. To determine if transmission of R. africae occurred, we used Rickettsia rickettsii antigen in IFA tests and found positive titers (≥ 1/80) with sera from cattle, goats, and sheep from Dominica (24/95 [25%], 2/136 [2%], 0/58 [0%]), Nevis (12/45 [27%], 5/157 [3%], 0/90 [0%]), St. Kitts (2/43 [5%], 1/25 [4%), 1/35 [3%]), and St. Lucia (6/184 [3%] cattle), respectively. No seropositive animals were found in Grenada (0/4, 0/98/, 0/86), Montserrat (0/12, 0/26, 0/52), or Puerto Rico (0/80 cattle). Our study indicates that R. africae and African tick-bite fever are widespread in the Caribbean.

Parasites of stray cats (Felis domesticus L., 1758) on St. Kitts, West Indies

During 2005-2006, 100 stray cats on St. Kitts were examined using standard parasitological methods. Eggs identified were those of hookworms (88%), Trichuris spp. (71%), Eucoleus aerophillus (16%), Mammomonogamus spp. (45%), Physaloptera spp. (18%), Toxocara spp. (4%), Platynosomum spp. (81%) and taeniids (30%). Coccidian oocysts were found in 12% of the cats and Ctenocephalides felis found on 26%. When the direct fecal smear, benchtop flotation, modified double centrifugation, fecal sedimentation and adhesive tape/scotch tape methods were compared, the modified double centrifugation and benchtop flotation techniques detected most of the positive samples for the widest variety of parasites; 50% (Toxocara spp.) to 100% (hookworms) and 100% (Toxocara spp.) to 96% (hookworms), respectively.

Feline immunodeficiency virus, feline leukemia virus and Bartonella species in stray cats on St Kitts, West Indies

Stray cats trapped in various areas of Basseterre, the capital of St Kitts in the West Indies, were tested for infection with feline immunodeficiency virus (FIV) and feline leukemia virus (FeLV) using commercial kits. Of 99 (51 male and 48 female) cats trapped in 2006/7, 15% (12 males and three females) were positive for FIV while none were positive for FeLV. Of 72 (41 males and 31 females) cats trapped in 2009, 14% (nine males and one female) were positive for FIV while none were positive for FeLV. Polymerase chain reaction analysis revealed DNA of Bartonella species in whole blood collected from 60/95 (63%) cats trapped in 2006/7. Sequencing of the 16S-23S rRNA gene intergenic transcribed spacer (ITS) region of a convenience sample of nine amplicons and the 11 isolates made from 43 blood samples which were cultured using Bartonella alpha Proteobacteria (BAPGM) enrichment medium revealed B henselae (14) and B clarridgeiae (six).

Inhibition of apoptosis in periodontitis

This study investigated whether the prolonged survival of inflammatory cells in periodontal disease could be due to the inhibition of apoptosis by tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) decoy receptors and inhibition of the terminal stages of apoptosis signaling by inhibitor of apoptosis (IAP) family members. Gingival tissue samples were taken from healthy individuals and those with chronic periodontitis. The expression of TRAIL, TRAIL receptors, TUNEL, cleaved caspase-3, xIAP, and survivin was determined immunohistologically and at the level of mRNA expression. Higher levels of TRAIL and the TRAIL decoy receptor, TRAIL R4, were expressed in the diseased periodontal tissues (p < 0.005). Statistically (p < 0.05) higher levels of cleaved caspase-3 and the cleaved caspase-3 inhibitors, xIAP and survivin, were seen. Similar changes were seen at the level of mRNA. The results indicate that apoptosis in periodontitis may be inhibited by elevated expression of TRAIL decoy receptors and cleaved caspase-3 inhibitors.

Failure to demonstrate Babesia, Anaplasma or Ehrlichia in thrombocytopenic dogs from St Kitts

BACKGROUND

Thrombocytopenia is common in dogs on St Kitts but there is no data on the possible etiological role played by infections with Anaplasma, Babesia and Ehrlichia, other than E. canis, which are known to occur in the Caribbean.

METHODOLOGY

Blood from 13 thrombocytopenic but apparently healthy dogs seronegative (Snap 3Dx) for E. canis were tested by PCR for Ehrlichia, Anaplasma and Babesia.

RESULTS

All PCRs were negative.

CONCLUSIONS

The results confirm the high sensitivity of SNAP testing for E. canis and indicate Anaplasma and Babesia are not important causes of thrombocytopenia in dogs on St Kitts.

Bioceramics composition modulate resorption of human osteoclasts

Biomaterials used in bone regeneration are designed to be gradually resorbed by the osteoclast and replaced by new bone formed through osteoblastic activity. The aim of the present study is to analyze the role of osteoclasts in the resorption process. The attachment of human osteoclasts and the appearance of their resorption lacunae, when cultured on either the resorbable crystalline, calcium orthophosphate materials or on the long-term stable bioceramic material was investigated. The resorbable materials contain Ca10[K,Na](PO4)7 (AW-Si) and Ca2KNa(PO4)2 (GB14, GB9 & D9/25) as their main crystal phases, however they differ in their total solubility. These differences result from small variations in the composition. The long-term stable material consist of about 30% fluorapatite beside calcium zirconium phosphate (Ca5(PO4)3F + CaZr4(PO4)6) and shows a very small solubility. AW-Si has an alkali containing crystalline phase, Ca10[K,Na](PO4). While GB14, GB9 and D9/25 contain the crystalline phase Ca2KNa(PO4)2 with small additions of crystalline and amorphous diphosphates and/or magnesium potassium phosphate (GB14). D9/25 and AW-Si is less soluble compared to GB14, and GB9 among the resorbable materials. Resorbable and long-term stable materials vary in their chemical compositions, solubility, and surface morphology. Osteoclasts modified the surface in their attempts to resorb the materials irrespective of the differences in their physical and chemical properties. The depth and morphology of the resorption imprints were different depending on the type of material. These changes in the surface structure created by osteoclasts are likely to affect the way osteoblasts interact with the materials and how bone is subsequently formed.

Localization of tyrosine phosphorylated proteins in human sperm and relation to capacitation and zona pellucida binding

Mammalian sperm must undergo a process known as capacitation before fertilization can take place. A key intracellular event that occurs during capacitation is protein tyrosine phosphorylation. The objective of this study was to investigate and visualize protein tyrosine phosphorylation patterns in human sperm during capacitation and interaction with the zona pellucida. The presence of specific patterns was also assessed in relation to the fertilizing capacity of the spermatozoa after in vitro fertilization. Protein tyrosine phosphorylation was investigated by immunofluorescence. Phosphorylation increased significantly with capacitation and was localized mainly to the principal piece of human sperm. Following binding to the zona pellucida, the percentage of sperm with phosphotyrosine residues localized to both the neck and the principal piece was significantly higher in bound sperm than in capacitated sperm in suspension. When the percentage of principal piece-positive sperm present after capacitation was <7%, fertilization rates after in vitro fertilization were reduced. Different compartments of human spermatozoa undergo a specific sequence of phosphorylation during both capacitation and upon binding to the zona pellucida. Tyrosine phosphorylation in the principal and neck piece may be considered a prerequisite for fertilization in humans.

Efficient transposition of the Tnt1 tobacco retrotransposon in the model legume Medicago truncatula

The tobacco element, Tnt1, is one of the few active retrotransposons in plants. Its transposition is activated during protoplast culture in tobacco and tissue culture in the heterologous host Arabidopsis thaliana. Here, we report its transposition in the R108 line of Medicago truncatula during the early steps of the in vitro transformation-regeneration process. Two hundred and twenty-five primary transformants containing Tnt1 were obtained. Among them, 11.2% contained only transposed copies of the element, indicating that Tnt1 transposed very early and efficiently during the in vitro transformation process, possibly even before the T-DNA integration. The average number of insertions per transgenic line was estimated to be about 15. These insertions were stable in the progeny and could be separated by segregation. Inspection of the sequences flanking the insertion sites revealed that Tnt1 had no insertion site specificity and often inserted in genes (one out of three insertions). Thus, our work demonstrates the functioning of an efficient transposable element in leguminous plants. These results indicate that Tnt1 can be used as a powerful tool for insertion mutagenesis in M. truncatula.

Economic transition should come with a health warning: the case of Vietnam

STUDY OBJECTIVE

s: To assess the affordability of health care to poor rural households in Vietnam under conditions of transition from a planned to a market economy and, in light of other transitional experience, inform policy on increasing access of the poor to affordable care of acceptable quality.

DESIGN

Observational study by cross sectional socioeconomic survey, longitudinal healthcare seeking survey, and qualitative semi-structured interviews and focus group discussions; qualitative follow up over six years.

SETTING

Four rural communes in north of Vietnam between 1992 and 1998. SURVEY PARTICIPANTS: 656 households (2995 people) selected by systematic random sampling.

MAIN RESULTS

Compared with non-poor households, poor households had significantly lower average per capita rates of healthcare consultation and expenditure (p<0.01 in both cases). Poor households delayed and minimised healthcare seeking, especially of expensive hospital services. Two thirds of average healthcare spending by poor households was on relatively inexpensive but frequent acts of local ambulatory care. The poor restrained their healthcare seeking but not in proportion to income: for households reporting illness, the average proportion of income devoted to health care was 21.9% for the poor compared with 8.2% for the non-poor (p<0.01). To meet healthcare costs, many poor households reduced essential consumption, sold assets and incurred debt, threatening their future livelihood.

CONCLUSIONS

In the short-term the poor need exemption from public sector user fees in both primary and hospital care. In the longer run the government budget and prepayment schemes should replace direct user charges in healthcare finance. Transitional economies like Vietnam should preserve the public health services built up under the planned economy. Market reforms that stimulate growth in the economy appear inappropriate to reform of social sectors.

The protease and reverse transcriptase of the tobacco LTR retrotransposon Tnt1 are enzymatically active when expressed in Escherichia coli

The open reading frame (ORF) of the tobacco retrotransposon Tnt1-94 was over-expressed in Escherichia coli to assay its protease and reverse transcriptase (RT) enzymatic activities. In E. coli, Tnt1-94 polyprotein is cleaved off by the element-encoded protease to release a Gag protein with an apparent molecular mass of 37 kDa that forms high-density aggregates. The catalytic site of Tnt1-94 protease (D-T-A) as determined by deletion analysis differs from that of retroviruses and of well-characterized retrotransposons (D-T/S-G). The cleaved or uncleaved ORF of Tnt1-94 displays an exogenous RT activity. Over-expression of plant retrotransposons ORFs in E. coli provides a very useful strategy to assay the enzymatic activities of their proteins and to determine their catalytic sites.

Tnt1 transposition events are induced by in vitro transformation of Arabidopsis thaliana, and transposed copies integrate into genes

Tissue culture has been shown to induce the transposition of plant transposable elements; their insertion at novel sites results in somaclonal variation. Introduction of the tobacco retrotransposon Tnt1 into Arabidopsis thaliana by co-cultivation of root explants with Agrobacterium tumefaciens induces its transposition at a high frequency, but no transposed copies are found in plants transformed by the in planta procedure. Transposition occurs in the transformed root cells or in the calli derived from them, allowing the regeneration of transformed plants with up to 26 transposed copies of Tnt1. Analysis of Tnt1 integration sites in Arabidopsis shows that the Tnt1 endonuclease does not show any cleavage-site specificity at the sequence level. The insertion sites are unlinked and distributed on all five Arabidopsis chromosomes. The fact that the majority of the integration sites are located in coding regions, and none in repeated sequences, demonstrates the potential of Tnt1 as a tool for gene tagging.

Effects of human hydrosalpinx fluid on in-vitro murine fertilization

Patients with hydrosalpinges show a decrease of both fertility and clinical outcome of IVF and embryo transfer treatment. Several reports have demonstrated the negative effects of hydrosalpinx fluid (HSF) on embryo development and implantation. The aim of this study was to determine whether human HSF, collected from infertile patients, might exhibit a deleterious effect on gametes and fertilization using a murine IVF system. Murine gametes were co-incubated during IVF until first cleavage with human HSF diluted to 50% from four patients (HSF1-4). It was demonstrated that HSF affected fertilization, as determined by the count of the 2-cell embryos. Pre-incubation of spermatozoa with HSF during capacitation significantly lowered the percentage of 2-cell embryos (P < 0.05). While HSF1-3 had no significant effect on motility and viability of spermatozoa, HSF4 almost completely affected their survival. In contrast, pre-incubation of ovulated oocytes surrounded by their cumulus cells with HSF before IVF did not impede first cleavage. Taken together, these results suggest that HSF has a cytotoxic effect on spermatozoa and/or impairs the fertilization process, probably by altering capacitation/acrosome reaction and/or ligand(s)-receptor(s) interactions. Hydrosalpinges may be partly associated with sterility through HSF inhibitory effects on fertilization.

A novel, rapid, and accurate method for detecting microdeletion involving the DAZ gene in infertile men

OBJECTIVE

To report on a novel, accurate method for detecting microdeletion involving the DAZ gene in infertile men.

DESIGN

Retrospective clinical study.

SETTING

University Infertility Center of Cochin Hospital, Paris, France.

PATIENT(S)

Infertile patients (n = 25) consulting our infertility department during 1998. The patient cohort included subjects with nonobstructive azoospermia and oligoasthenospermia.

INTERVENTION(S)

Blood samples were collected from each subject.

MAIN OUTCOME MEASURE(S)

DNA analysis using polymerase chain reaction (PCR)-denaturing gradient gel electrophoresis (DGGE).

RESULT(S)

We used a new molecular genetic strategy to rapidly identify deletions of the Y chromosome that include the DAZ locus. The experiment consists of amplifying simultaneously exon 4 of the DAZ and DAZLA genes with the use of specific primers that are complementary to intronic sequences of these genes. DGGE was used to separate the two PCR products, with good resolution. In infertile men with a microdeletion of the DAZ gene, this method allows amplification of an internal control when a deletion of that portion of the Yq chromosome is observed on a single amplification.

CONCLUSION(S)

This PCR-DGGE method for detection of DAZ gene deletion is simple and fast and does not require the use of radioactive elements. Compared with the classic PCR approach, this new method allows the amplification of the DAZLA copy to be used as an effective internal control in infertile men with microdeletion of the DAZ locus. This procedure could be particularly useful in screening for the DAZ locus in the diagnostic workup of nonobstructive azoospermia and severe oligoasthenoteratozoospermia.

Design, synthesis and testing of amino-bicycloaryl based orally bioavailable thrombin inhibitors

Replacement of the highly basic benzamidine moiety with moderate basic amino-bicycloaryl moieties in a series of thrombin inhibitors related to NAPAMP provided potent enzyme inhibition and significant improvements in membrane transport and oral bioavailability.

1-Aminoisoquinoline as benzamidine isoster in the design and synthesis of orally active thrombin inhibitors

Replacement of the highly basic benzamidine moiety of NAPAP by the moderately basic 1-aminoisoquinoline moiety resulted in thrombin inhibitors with improved selectivity towards trypsin and enhanced Caco-2 cell permeability.

Novel acylguanidine containing thrombin inhibitors with reduced basicity at the P1 moiety

Replacement of the noragmatine group in thrombin inhibitors with a beta-alanyl-guanidine group resulted in a nearly equipotent and more selective compound 8 despite the fact that the pKa of this P1 moiety is five orders of magnitude lower. Further modification resulted in a nonpeptide inhibitor with this beta-alanyl-guanidine group, compound 28. This is an active and selective thrombin inhibitor and in view of its nonpeptide/low basicity structure selected for further pharmacological studies.

Myelomeningocele and Waardenburg syndrome (type 3) in patients with interstitial deletions of 2q35 and the PAX3 gene: possible digenic inheritance of a neural tube defect

From a spina bifida clinic we have identified two patients with a syndrome of myelomeningocele and Waardenburg syndrome type 3 (WS3). The patients each possess a single, de novo, interstitial deletion of chromosome 2 (2q35-36.2), including the PAX3 gene. Deletion of PAX3 was confirmed by fluorescence in situ hybridization (FISH). Analysis with PAX3 and flanking microsatellites shows that the deleted interval of chromosome 2 is of paternal origin and is at least 2 and 6 cM in the two patients. Interstitial deletions in this region result in the Waardenburg syndrome (WS1), but have not been associated with neural tube defects (NTDs). Although other etiologies have not been formally excluded, these patients raise the possibility of a digenic etiology of their NTDs via a genetic interaction of the deleted PAX3 gene with a second unidentified locus.

Retrovirus-like end processing of the tobacco Tnt1 retrotransposon linear intermediates of replication

The tobacco retrotransposon Tnt1 can transpose through an RNA intermediate in the heterologous host Arabidopsis thaliana. We report here the identification and characterization of extrachromosomal linear and circular DNA forms of Tnt1 in this heterologous host. Our results demonstrate that Tnt1 linear intermediates possess two extra base pairs at each end compared with Tnt1's integrated forms. Prior to integration into the host genome, the two terminal nucleotides at the 3' end of these linear intermediates are removed, as in the case of the yeast Ty3 retrotransposon and of retroviruses. Our data, together with those from recent studies of Ty3, reinforce the idea that 3' dinucleotide cleavage is not restricted to retroviral integrases and is probably a feature shared by many different retrotransposons' enzymes.

[The future of male contraception: immunocontraception by preventing gamete interaction]

This paper summarize the main data relevant to the obtention of contraceptive vaccines based on spermatozoa as well as zona pellucida antigens. The development of novel forms of contraception is one way in which this global population problems can be tackled. The sperm as well as the oocyte antigens are studied as possible contraceptive vaccine candidates are the subject of this review.

The expression of the tobacco Tnt1 retrotransposon is linked to plant defense responses

Activation of retrotransposons by stresses and external changes is common in all eukaryotic systems, including plants. The transcription of the tobacco Tnt1 retrotransposon was studied in its natural host as well as in Arabidopsis and tomato. It is activated by factors of microbial origin, by external stresses, and by viral, bacterial, and fungal attacks. Tnt1 expression is linked with the biological responses of the plant to the elicitor or to the pathogen attack and in particular with the early steps of the metabolic pathways leading to the activation of plant defense genes. In most cases, the basic features of Tnt1 regulation in tobacco are maintained in tomato and Arabidopsis, but some host-specific regulations were shown. The U3 region of the Tnt1 LTR contains the major cis-acting components of Tnt1 transcriptional activation in association with the plant defense responses. Furthermore, the Tnt1 U3 region, and especially the tandemly repeated BII boxes, contains several sequences similar to well-characterized motifs involved in the activation of several plant defense genes. The possible origin of Tnt1 regulatory sequences as well as the biological implications of Tnt1 activation by pathogen attacks are discussed.

The promoter of the tobacco Tnt1 retrotransposon is induced by wounding and by abiotic stress

The transcription of the tobacco Tnt1 retrotransposon was previously shown to be induced, in tobacco and in heterologous species, by microbial elicitors and by pathogen infections. We report here that the expression of the Tnt1 promoter is also activated in heterologous species such as tomato and Arabidopsis by wounding, freezing and by other abiotic factors known to induce the plant defence response, such as salicylic acid, CuCl2, or oxidative stress. A similar regulation is observed in tobacco for most treatments. The induction of the Tnt1 promoter expression by wounding remains localized around injury points. In CuCl2-treated Arabidopsis plants, the transcription of Tnt1 is correlated with accumulation of the phytoalexin camalexin and with the expression of the EL13 defence gene. The interest of the Tnt1 promoter as a sensitive indicator of the plant defence responses is discussed.

Central venous catheter tip position and malfunction in a paediatric oncology unit

An audit of 151 central venous catheters (CVCs) in 118 children with malignant disease was carried out over 20 months. The types included 31 valved silastic (Groshong), 58 non-valved silastic (Hickman), and 62 non-valved polyurethane (Cuff Cath) CVCs. There was no difference between the three groups with regard to the clinical diagnosis. The mean patient age at catheter insertion was 5.5 years and the mean weight 21.6 kg. None of the catheter types were associated with an increased risk of problems at insertion, migration, mechanical damage, blockage, sampling, or catheter infection. The incidence of catheter infection was 1.4/1,000 catheter days. Exit-site infection was less frequent with Groshong CVCs (P <0.05), which were in situ for the shortest period. The risk of problems with blood sampling was significantly increased in those catheters whose tip was sited outside the right atrium (P <0.005). For the 60 CVCs removed electively, the mean duration in situ was similar for all catheter types; 43 were removed following a problem. Of these, Groshong catheters were in situ for the shortest period (P = 0.05), probably as a result of delayed anchoring of the cuff. The tip position was the single most important determinant in the correct functioning of CVCs, irrespective of the type of catheter. Intraoperative screening of the tip position at catheter insertion is therefore mandatory for optimal catheter functioning.

[Identification of spermatozoa L-selectin and two potential pellucida ligands]

At the molecular level, gamete interactions partly depend on zona pellucida-glycoproteins fucosylation. We show, by immunocytochemistry, the sialyl-lewisx and sialyl-lewisa oligosaccharides on human zonae pellucidae. These epitopes are potential ligands of cell adhesion molecules named selectins which are known to play a role in endothelium-leukocyte interactions. By immunofluorescence, we find the leukocyte selectin (L-selectin) on the spermatozoa head. Preincubation of spermatozoa with an anti-L-selectin monoclonal antibody produces a significant inhibition of zona pellucida tight binding, under hemizona assay conditions. In contrast, preincubation of the zonae pellucidae with anti-sialyl-lewisx or anti-sialyl-lewisa antibodies does not produce a significant inhibition of spermatozoa binding. Western blot analysis of spermatozoa-detergent extracts revealed a band at approximatively 90 kDa with the anti-L-selectin monoclonal antibody. This spermatozoa selectin could play a role in human spermatozoa-zona pellucida binding. Zona-ligands have yet to be precisely defined.

Composition of human zona pellucida as revealed by SDS-PAGE after silver staining

The macromolecular composition of zona pellucida (ZP) isolated from human oocytes and embryos was characterized by one- and two-dimensional sodium dodecyl sulfate polyacrylamide gel electrophoresis (1-D- and 2-D-SDS-PAGE) under reducing conditions after silver staining. ZP specimens obtained after in vitro fertilization were removed from pools of heavily fragmented embryos and inseminated oocytes that failed to fertilize. For unfertilized oocytes, two major bands with an apparent molecular weight of, respectively, 96 and 76-54 kDa were observed after 1-D-SDS-PAGE and silver staining. When ZP were isolated from fragmented embryos, the electrophoretic pattern showed a marked attenuation of the 96-kDa band. Silver-stained 2-D-SDS-PAGE analysis of ZP components from unfertilized oocytes revealed the presence of four protein trains: ZP1 (Mr = 92-80 kDa, pl = 4.9-5.9), ZP2 (Mr = 66-58 kDa, pl = 5.0-6.0), ZP3H (high) (Mr = 72-58 kDa, pl = 3.5-5.1), and ZP3L (low) (Mr = 62-54 kDa, pl = 3.5-5.1). The human ZP3 family (ZP3H and ZP3L) showed marked heterogeneity. Fertilization-associated changes were apparent in the electrophoretic pattern. ZP1 (Mr = 92-86 kDa, pl = 5.0-5.8) displayed a dramatic decrease in intensity, and a new component had migrated to a position similar to that of ZP2. This modification may have been responsible for one aspect of the zona reaction, and could have contributed to a zona block to polysperma.

RNA-mediated transposition of the tobacco retrotransposon Tnt1 in Arabidopsis thaliana

The tobacco (Nicotiana tabacum) retrotransposon Tnt1 was introduced into Arabidopsis thaliana. In this heterologous host plant species, Tnt1 undergoes an RNA-mediated transposition and creates a 5 bp duplication at the insertion sites. This is the first report of transposition of a retrotransposon after introduction into a heterologous host species. Tnt1 transposed during in vitro regeneration of transformed A.thaliana, but no transposition event was detected as happening in T2 and T3 generation plants. Newly synthesized copies of Tnt1 can integrate into coding regions of the host DNA. Our results open up the possibility of using Tnt1 as a new tool for insertional mutagenesis and functional analysis of plant genomes, in addition to the strategies of T-DNA and transposon tagging.

Feasible synthesis and biological properties of six 'non-glycosamino' glycan analogues of the antithrombin III binding heparin pentasaccharide

In this paper, we report the synthesis of 'non-glycosamino' glycan analogues 5-10 of the antithrombin III binding pentasaccharide 1. Pentasaccharides 5-10 feature a pseudo-alternating EFGH tetrasaccharide sequence, that is, the disaccharide fragments EF and GH have the same substitution pattern. In the synthetic strategy applied for the synthesis of pentasaccharides 5-10, the properly protected EF disaccharide fragments 19 and 20 are obtained from their GH counterparts 17 and 18 by base-catalyzed epimerization. Series I, comprising pentasaccharides 5-7, has an invariable EFGH tetrasaccharide containing 2-O-sulfate 3-O-methyl uronic acid moieties. Series II, on the other hand, contains pentasaccharides 8-10 and has an invariable EFGH tetrasaccharide containing 2,3-di-O-methyl uronic acid moieties. Coupling disaccharides 17 with 25 and 18 with 26 exclusively afforded the alpha-coupled tetrasaccharides 27 and 28, respectively. Glycosylation of acceptor tetrasaccharides 29 and 30 with glucosyl donors 35, 36 and 39 provided, after deprotection and sulfation, the title-compounds 5-10. Biological data obtained with series I and II indicate that the in vivo half-life but not the intrinsic anti-Xa activity depends on the substitution pattern of the D-unit. In addition, the applicability of reversed UV capillary electrophoresis as an analytical tool to determine the purity of these 'non-glycosamino' glycans is demonstrated.