Optimization of dengue virus genome assembling using GSFLX 454 pyrosequencing data: evaluation of assembling strategies

Currently assembling genomes without reference is one of the most important challenges for bioinformaticists all over the world in an attempt to characterize new organisms. The current study has used two dengue virus type 4 (DENV-4) strains recently isolated in Brazil, which have its genomes sequenced using the GSFLX 454 sequencer (Roche, Life Science) by the pyrosequencing method. The GSFLX 454 data were used for testing different genome assembling strategies. We described a pipeline that was able to recover more than 96% of the sequenced genome in a single run and could be helpful for further assembly attempts of other DENV genomes, as well as other RNA virus-like genomes.

Feline Leishmania infection in a canine leishmaniasis endemic region, Portugal

Canine leishmaniasis (CanL) caused by Leishmania infantum is a serious zoonotic public health and veterinary problem in the Mediterranean basin. Leishmania infection in domestic cats (Felis catus domesticus) has been reported in several countries where this zoonosis is endemic, such as Portugal, Spain, Italy, France, Greece, Israel, Palestine and Brazil. The aim of this study was to contribute to the knowledge of the role played by cats in Leishmania epidemiology, in an endemic focus of zoonotic leishmaniasis, the Lisbon metropolitan area, Portugal. L. infantum DNA was detected in peripheral blood of 28 out of 138 cats (20.3%). The result of PCR in blood of cats was not closely associated with the level of specific circulating antibodies in their sera. Positive serology was observed only in one cat out of 76. In the same geographic region and time period the indirect immunofluorescent test revealed 20.4% (31/152) of dogs with antibodies and PCR detected Leismania DNA on 34.9% (53/152) animals. Despite the fact that specific antibodies have been validated for diagnosis of CanL, their detection does not seem to be sensitive enough to predict Leishmania infection in cats. On the other hand, the presence of parasite DNA in cat's peripheral blood during the transmission season and out of the season suggests that these animals living in endemic areas are frequently exposed or infected with the parasite. Although dogs have been universally regarded as the major domestic/peridomestic reservoir hosts, the present data allow us to hypothesize that cats can act as an alternative reservoir host of L. infantum, rather than an accidental host. However, in order to evaluate the existence of a transmission cycle with cats sustaining and spreading zoonotic leishmaniasis is necessary to prove that these animals can transmit the parasite to the vector in nature.

The macrobenthic community along a mercury contamination in a temperate estuarine system (Ria de Aveiro, Portugal)

Mercury is a widely distributed environmental pollutant and a toxic element to all living organisms. This study represents an attempt to evaluate its correlation with the macrobenthic community structure in a temperate estuarine system, the Ria de Aveiro (Portugal). The macrobenthic community structure showed significant differences along the mercury gradient. Overall, the increase of mercury contamination was associated with reduced total abundance, lower species richness, and dominance of tolerant taxa. The polychaetes Hediste diversicolor and Alkmaria romijni, and the isopod Cyathura carinata were associated with high levels of mercury in sediment, while the bivalves Scrobicularia plana, Cerastoderma edule and Abra alba showed higher density in lesser contaminated sites. Furthermore, highly contaminated sites showed substantially lower abundances of surface-deposit feeders and herbivores, and higher abundances of subsurface-deposit feeders and omnivores. Salinity was also a significant factor affecting the community, being responsible for seasonal variations in the macrobenthic assemblages.

Infectivity of five different types of macrophages by Leishmania infantum

Leishmania are intracellular parasites that multiply as the amastigote form in the macrophages of their vertebrate hosts. Since vaccines against leishmaniases are still under development, the control of these diseases relies on prompt diagnosis and chemotherapy in infected humans as well as in dogs, which are the main reservoir of Leishmania infantum, in Mediterranean countries. To establish the macrophage type to be used as an in vitro model for antileishmanial chemotherapeutic studies, we analysed the susceptibility of human peripheral blood derived macrophages, macrophages derived from mouse bone marrow, mouse peritoneal macrophages and macrophages differentiated from cell lines U-937 and DH82 to infection by two L. infantum strains, one obtained from a human leishmanial infection and other from a canine infection. Both strains displayed comparable behaviour in their capacity of infecting the different macrophage types. Human peripheral blood macrophages and DH82 cells were less infectable by both strains. U-937, mouse peritoneal macrophages and mouse bone marrow derived macrophages are the most active cells to phagocytose the parasites. However, U-937 cell line appears to be the most useful as Leishmania infection model providing an unlimited source of homogeneous host cells with reproducibility of the results, is less time consuming, less expensive and tolerate high doses of first line drugs for human and canine visceral leishmaniasis treatment.

Purinergic signaling regulates neural progenitor cell expansion and neurogenesis

Neural stem and progenitor cells typically exhibit a density-dependent survival and expansion, such that critical densities are required below which clonogenic progenitors are lost. This suggests that short-range autocrine factors may be critical for progenitor cell maintenance. We report here that purines drive the expansion of ventricular zone neural stem and progenitor cells, and that purine receptor activation is required for progenitor cells to be maintained as such. Neural progenitors expressed P2Y purinergic receptors and mobilized intracellular calcium in response to agonist. Receptor antagonists suppressed proliferation and permitted differentiation into neurons and glia in vitro, while subsequent removal of purinergic inhibition restored progenitor cell expansion. Real-time bioluminescence imaging of extracellular ATP revealed that the source of extracellular nucleotides are the progenitor cells themselves, which appear to release ATP in episodic burst events. Enzyme histochemistry of the adult rat brain for ectonucleotidase activity revealed that NTDPase, which acts to degrade active ATP and thereby clears it from areas of active purinergic transmission, was selectively localized to the subventricular zone and the dentate gyrus, regions in which neuronal differentiation proceeds from the progenitor cell pool. These data suggest that purine nucleotides act as proliferation signals for neural progenitor cells, and thereby serve as negative regulators of terminal neuronal differentiation. As a result, progenitor cell-derived neurogenesis is thus associated with regions of both active purinergic signaling and modulation thereof.

Progenitor cells derived from the adult human subcortical white matter disperse and differentiate as oligodendrocytes within demyelinated lesions of the rat brain

A distinct population of white matter progenitor cells (WMPCs), competent but not committed to generate oligodendrocytes, remains ubiquitous in the adult human subcortical white matter. These cells are present in both sexes and into senescence and may constitute as much as 4% of the cells of adult human capsular white matter. Transduction of adult human white matter dissociates with plasmids bearing early oligodendrocytic promoters driving fluorescent reporters permits the separation of these cells at high yield and purity, as does separation based on their expression of A2B5 immunoreactivity. Isolates of these cells survive xenograft to lysolecithin-demyelinated brain and migrate rapidly to infiltrate these lesions, without extending into normal white matter. Within several weeks, implanted progenitors mature as oligodendrocytes, and develop myelin-associated antigens. Lentiviral tagging with green fluorescent protein confirmed that A2B5-sorted progenitors develop myelin basic protein expression within regions of demyelination and that they fail to migrate when implanted into normal brain. Adult human white matter progenitor cells can thus disperse widely through regions of experimental demyelination and are able to differentiate as myelinating oligodendrocytes. This being the case, they may constitute appropriate vectors for cell-based remyelination strategies.

Prevalence of visual impairment in people aged 75 years and older in Britain: results from the MRC trial of assessment and management of older people in the community

AIMS

To measure the prevalence of visual impairment in a large representative sample of people aged 75 years and over participating in the MRC trial of assessment and management of older people in the community.

METHODS

53 practices in the MRC general practice research framework. Data were obtained from 14 600 participants aged 75 years and older. Prevalence of visual impairment overall (binocular visual acuity <6/18) which was categorised separately into low vision (binocular visual acuity <6/18-3/60) or blindness (binocular visual acuity of <3/60). The prevalence of binocular acuity <6/12 was presented for comparison with other studies. Visual acuity was measured using Glasgow acuity charts; glasses, if worn, were not removed.

RESULTS

Visual acuity was available for 14 600 people out of 21 241 invited (69%). Among people with visual acuity data, 12.4% overall (1803) were visually impaired (95% confidence intervals 10.8% to 13.9%); 1501 (10.3%) were categorised as having low vision (8.7% to 11.8%), and 302 (2.1%) were blind (1.8% to 2.4%). At ages 75-79, 6.2% of the cohort were visually impaired (5.1% to 7.3%) with 36.9% at age 90+ (32.5% to 41.3%). At ages 75-79, 0.6% (0.4% to 0.8%) of the study population were blind, with 6.9% (4.8% to 9.0%) at age 90+. In multivariate regression, controlling for age, women had significant excess risk of visual impairment (odds ratio 1.43, 95% confidence interval 1.29 to 1.58). Overall, 19.9% of study participants had a binocular acuity of less than 6/12 (17.8% to 22.0%).

CONCLUSION

The results from this large study show that visual impairment is common in the older population and that this risk increases rapidly with advancing age, especially for women. A relatively conservative measure of visual impairment was used. If visual impairment had been defined as visual acuity of <6/12 (American definition of visual impairment), the age specific prevalence estimates would have increased by 60%.

Randomised comparison of three methods of administering a screening questionnaire to elderly people: findings from the MRC trial of the assessment and management of older people in the community

OBJECTIVE

To compare three different methods of administering a brief screening questionnaire to elderly people: post, interview by lay interviewer, and interview by nurse.

DESIGN

Randomised comparison of methods within a cluster randomised trial.

SETTING

106 general practices in the United Kingdom.

PARTICIPANTS

32 990 people aged 75 years or over registered with participating practices.

MAIN OUTCOME MEASURES

Response rates, proportion of missing values, prevalence of self reported morbidity, and sensitivity and specificity of self reported measures by method of administration of questionnaire for four domains.

RESULTS

The response rate was higher for the postal questionnaire than for the two interview methods combined (83.5% v 74.9%; difference 8.5%, 95% confidence interval 4.4% to 12.7%, P<0.001). The proportion of missing or invalid responses was low overall (mean 2.1%) but was greater for the postal method than for the interview methods combined (4.1% v 0.9%; difference 3.2%, 2.7% to 3.6%, P<0.001). With a few exceptions, levels of self reported morbidity were lower in the interview groups, particularly for interviews by nurses. The sensitivity of the self reported measures was lower in the nurse interview group for three out of four domains, but 95% confidence intervals for the estimates overlapped. Specificity of the self reported measures varied little by method of administration.

CONCLUSIONS

Postal questionnaires were associated with higher response rates but also higher proportions of missing values than were interview methods. Lower estimates of self reported morbidity were obtained with the nurse interview method and to a lesser extent with the lay interview method than with postal questionnaires.

Diagnosis of Oropouche virus infection using a recombinant nucleocapsid protein-based enzyme immunoassay

Oropouche (ORO) virus is an emerging infectious agent that has caused numerous outbreaks of an acute febrile (dengue-like) illness among humans in Brazil, Peru, and Panama. Diagnosis of ORO virus infection is based mainly on serology. Two different antigens, hamster serum antigen (HSA) and Vero cell lysate antigen (VCLA), are currently used in enzyme immunoassays (EIAs) in Brazil and Peru, respectively, to investigate the epidemiology of ORO virus infection. Both antigens involve use of infectious virus, and for this reason their use is restricted. Consequently, the frequency and distribution of ORO virus infection are largely unexplored in other countries of South America. This report describes the use of a bacterially expressed recombinant nucleocapsid (rN) protein of ORO virus in EIAs for the diagnosis of ORO virus infection. The data revealed that the purified rN protein is comparable to the authentic viral N protein in its antigenic characteristics and is highly sensitive and specific in EIAs. Among 183 serum samples tested, a high degree of concordance was found between rN protein-based EIA and HSA- and VCLA-based EIAs for the detection of both ORO virus-specific immunoglobulin M (IgM) and IgG antibodies. The high sensitivity, specificity, and safety of the rN protein-based EIA make it a useful diagnostic technique that can be widely used to detect ORO virus infection in South America.

NSPc1, a novel mammalian Polycomb gene, is expressed in neural crest-derived structures of the peripheral nervous system

Anterior-posterior (A-P) patterning is a key element in early embryonic development. Polycomb group (PcG) genes act as transcriptional repressors to regulate A-P patterning by either directly or indirectly controlling the coordinated expression of the HOM/Hox homeobox (Curr. Opin. Genet. Dev. 7 (1997) 488; Trends Genet. 13 (1997) 167). We describe the isolation and characterization of a novel mammalian PcG gene, termed Nervous System Polycomb-1 (NSPc1). Human and mouse NSPc1 genes encode proteins with an N-terminal RING finger domain and share homology with Drosophila melanogaster lethal(3)73Ah and the mammalian Mel18 and Bmi1 genes. Transcripts are observed at 10 dpc in the otic vesicle, urogenital bud and dorsal root ganglia. At 11.5 dpc, transcripts are present in a subset of neural crest cell derivatives of the peripheral nervous system, and in the neural tube. NSPc1 expression is ubiquitous in adult tissue.

Combinatorial chemoprevention of intestinal neoplasia

A combination of two drugs afforded remarkable protection from intestinal neoplasia in APC(Min/+) mice, a murine model of human familial adenomatous polyposis (FAP). One of the drugs was sulindac, a prototypical non-steroidal anti-inflammatory drug with established chemopreventative activity. The second drug was EKI-569, a newly developed, irreversible inhibitor of the epidermal growth factor receptor kinase. Although 100% of the untreated APC(Min/+) mice developed approximately 20 polyps, nearly half the mice treated with these two agents developed no polyps at all. These results suggest a powerful strategy for the chemoprevention of human colonic neoplasia.

Is it advantageous to lower cholesterol in the elderly hypertensive?

Hypertension is often associated with other risk factors for cardiovascular disease, including elevated levels of cholesterol, and casual systolic hypertension is a very prevalent finding in the elderly (50% of women over the age of 80 have casual systolic blood pressures > or = 160 mmHg). Total cholesterol levels steadily increase with age from 20 to 65, following which they decrease slightly in men and tend to plateau in women. Elevated cholesterol levels are not uncommon in the elderly (61% of women aged between 65 and 74 have total cholesterol levels over 6.2 mmol/L [240 mg/dL]). From the data available, it is reasonable to conclude that after the age of 65, increased blood lipids, although still a risk factor for coronary heart disease (CHD), become less pronounced as risk factors and that by 75 years of age their predictive value has disappeared. Indeed, in the very elderly, there is evidence to suggest that high total cholesterol is associated with longevity. In elderly hypertensives with elevated serum cholesterol, differing risks have been reported. The European Working Party on Hypertension in the Elderly (EWPHE) trial suggested a negative relationship between cholesterol and mortality, while the Systolic Hypertension in the Elderly Program (SHEP) trial suggested a positive relationship. With regards to intervention, it is well documented that antihypertensive treatment in elderly hypertensives up to the age of 80 who have blood pressures over 160 mmHg systolic is associated with significant reductions in stroke and cardiovascular events. The efficacy of dietary modification in reducing cholesterol in the elderly has been supported by some studies but not by all. Three major intervention trails using statins have shown that in elderly patients up to the age of 70-75 who have established CHD, lipid-lowering therapy can be of benefit. The experience from these and other trials suggests that statins are generally well tolerated in the elderly. It is difficult and premature to extrapolate these results to elderly patients who have hypertension and raised cholesterol levels without established CHD. Further trials are required before routinely suggesting it is advantageous to lower cholesterol in an elderly hypertensive who does not have pre-existing evidence of CHD. It is possible that large numbers may prove to require treatment.

Nucleotide sequences and phylogeny of the nucleocapsid gene of Oropouche virus

The nucleotide sequence of the S RNA segment of the Oropouche (ORO) virus prototype strain TRVL 9760 was determined and found to be 754 nucleotides in length. In the virion-complementary orientation, the RNA contained two overlapping open reading frames of 693 and 273 nucleotides that were predicted to encode proteins of 231 and 91 amino acids, respectively. Subsequently, the nucleotide sequences of the nucleocapsid genes of 27 additional ORO virus strains, representing a 42 year interval and a wide geographical range in South America, were determined. Phylogenetic analyses revealed that all the ORO virus strains formed a monophyletic group that comprised three distinct lineages. Lineage I contained the prototype strain from Trinidad and most of the Brazilian strains, lineage II contained six Peruvian strains isolated between 1992 and 1998, and two strains from western Brazil isolated in 1991, while lineage III comprised four strains isolated in Panama during 1989.

Flexible foraging strategy of Cory's shearwater, Calonectris diomedea, during the chick-rearing period

Procellariiformes are well known for their low rates of food provisioning to their slow-growing chicks. In some species, the patterns of food delivery to chicks have been deduced from changes in their weight, obtained from periodic weighings. However, the behaviour of individual parents cannot be resolved using this method. In this study, we used a periodic weighing protocol with Cory's shearwater chicks on Selvagem Grande island, in the northeast Atlantic. In addition, we used an automatic logging system to examine the attendance of individual parents. In 1997, the chicks were fed infrequently, and were in significantly poorer condition, than in other years and at other colonies. This suggests that the adults were experiencing some difficulties in finding an adequate food supply close to the colony. Under these conditions, individual parents adopted a dual provisioning strategy, making both short and long foraging trips, a previously undescribed behaviour in any northern hemisphere petrel species. Although meals delivered to chicks were larger after long trips than after short trips, the average amount of food provisioned per day spent at sea decreased with increasing trip length, and so chicks did not benefit from longer trips. This finding suggests that long trips can be used to restore the adult's body condition, presumably depleted during short trips as shown previously for some petrels and albatrosses. The adoption of this flexible foraging strategy, which differs from the uniform intervals observed in Cory's shearwaters experiencing situations of 'normal' food abundance, may represent a mechanism through which breeding birds compromise between the needs of their chicks and the maintenance of their own body condition. Copyright 1998 The Association for the Study of Animal Behaviour.

Atmospheric impact assessment and monitoring of dioxin emissions of municipal solid waste incinerators in Portugal

In Portugal two municipal solid waste (MSW) incinerators are under construction in the metropolitan areas of Lisbon and Porto. During the development of the Environmental Impact Assessment (EIA) studies of these units the authors found several limitations and uncertainties associated to the assessment of the environmental impact. Uncertainties were particularly felt on the assessment of the environmental impacts associated with the atmospheric emissions of PCDD and PCDF. At present an External Monitoring Plan is under design.

Failure of testicular development associated with a rearrangement of 9p24.1 proximal to the SNF2 gene

In 46,XY individuals, testes are determined by the activity of the SRY gene (sex-determining region Y), located on the short arm of the Y chromosome. The other genetic components of the cascade that leads to testis formation are unknown and may be located on the X chromosome or on the autosomes. Evidence for the existence of several loci associated with failure of male sexual development is indicated by reports of 46,XY gonadal dysgenesis associated with structural abnormalities of the X chromosome or of autosomes (chromosomes 9, 10, 11 and 17). In this report, we describe the investigation of a child presenting with multiple congenital abnormalities, mental retardation and partial testicular failure. The patient had a homogeneous de novo 46,XY,inv dup(9)(pter-->p24.1::p21.1-->p23.3::p24.1-->qter) chromosome complement. No deletion was found by either cytogenetic or molecular analysis. The SRY gene and DSS region showed no abnormalities. Southern blotting dosage analysis with 9p probes and fluorescent in situ hybridisation data indicated that the distal breakpoint of the duplicated fragment was located at 9p24.1, proximal to the SNF2 gene. We therefore suggest that a gene involved in normal testicular development and/or maintenance is present at this position on chromosome 9.

Identification of Trypanosoma cruzi trans-sialidase family members as targets of protective CD8+ TC1 responses

CD8+ T lymphocytes play a critical role in immunity to Trypanosoma cruzi. However, the target molecules of this T cell subset have not been elucidated. In this work, we report the identification of an H-2Kb-restricted CTL epitope within two trypomastigote surface Ags encoded by members of the T. cruzi sialidase/trans-sialidase gene superfamily. Octapeptide VDYNFTIV sensitized target cells for lysis by CD8+ CTL generated from spleens of T. cruzi-infected mice. Peptide-specific CD8+ T cell lines were cytotoxic, secreted IFN-gamma and TNF-alpha, but low to undetectable levels of IL-4 and IL-5, and were able, upon adoptive transfer, to confer a high degree of protection against challenge infection. Finally, the protective determinant appears to be conserved among parasites from diverse geographic locations. This constitutes the first identified class I MHC-restricted epitope in T. cruzi and provides the basis for the search of additional targets to be considered in the development of vaccines against Chagas' disease.

Identification of Trypanosoma cruzi trans-sialidase family members as targets of protective CD8+ TC1 responses

CD8+ T lymphocytes play a critical role in immunity to Trypanosoma cruzi. However, the target molecules of this T cell subset have not been elucidated. In this work, we report the identification of an H-2Kb-restricted CTL epitope within two trypomastigote surface Ags encoded by members of the T. cruzi sialidase/trans-sialidase gene superfamily. Octapeptide VDYNFTIV sensitized target cells for lysis by CD8+ CTL generated from spleens of T. cruzi-infected mice. Peptide-specific CD8+ T cell lines were cytotoxic, secreted IFN-gamma and TNF-alpha, but low to undetectable levels of IL-4 and IL-5, and were able, upon adoptive transfer, to confer a high degree of protection against challenge infection. Finally, the protective determinant appears to be conserved among parasites from diverse geographic locations. This constitutes the first identified class I MHC-restricted epitope in T. cruzi and provides the basis for the search of additional targets to be considered in the development of vaccines against Chagas' disease.

Deletions of distal 9p associated with 46,XY male to female sex reversal: definition of the breakpoints at 9p23.3-p24.1

Monosomy of distal 9p is associated in rare cases with abnormalities of testicular determination, which can lead to male to female sex reversal in a 46,XY genetic background. We present two 46,XY individuals partially monosomic for 9p who were raised as females. Definition of the breakpoints using somatic cell hybrids containing only the rearranged chromosome 9 indicated that in the first patient the breakpoint was located between markers D9S256 and D9S144 and in the second patient, the breakpoint was distal to the marker D9S144. In both cases this corresponds to the cytogenetic position 9p23.3-p24.1. Analysis of highly polymorphic microsatellite markers demonstrated a paternal origin of the rearranged chromosome 9 in both patients. These studies define the minimum region associated with male to female sex reversal as 9p24.1-pter.

Hypertelorism and hypospadias associated with a de novo apparently balanced translocation between 8q22.3-23 and 20p13

A de novo apparently balanced translocation involving chromosomes 8 and 20 was found in a 14-year-old boy with minor anomalies, mild skeletal abnormalities and ambiguous external genitalia including perineoscrotal hypospadias, rudimentary fused labioscrotal folds, bilateral cryptorchidism, and small penis. The karyotype was 46,XY, t(8;20)(q22.3-23;p13). No signs of other conditions known to be associated with structural anomalies of either chromosome 8 or 20 were present and incomplete masculinisation of the external genitalia appears to be the main component of the phenotype. Clinical and biological studies showed apparently normal testicular function in utero and after birth. Examinations excluded 5 alpha-reductase deficiency or a block in any enzymatic steps of testosterone, glucocorticoid and mineralocorticoid biosynthesis. Coding sequences of the sex-determining gene (SRY) and androgen receptor gene (AR) were found to be identical to those of a normal male excluding their role in the cause of the present condition. Since several other reports describe the association of hypospadias and hypertelorism with deletions or translocations involving 8q, we suggest that a locus necessary for male sex differentiation is located at distal 8q.

Swine cytosolic malic enzyme: cDNA cloning, sequencing, and localization

A highly significant genetic association has been found between some alleles of the swine Major Histocompatibility Complex SLA (Swine Leukocyte Antigen genetic complex) and the cytosolic malic enzymatic activity level in muscles. The aim of this study was to find out whether this genetic association was due to a close linkage of the SLA region and the gene coding for the enzyme. Since no swine cytosolic malic enzyme sequence (ME1) was available, we isolated several overlapping fragments that spanned the almost entire malic enzyme transcript both by screening of a swine cDNA library and by RT-PCR. The results indicated the existence of two transcripts of 2. 0 and 3.1 kb, which probably correspond to two alternative forms of one gene. The sequence of the transcript was highly similar to the other published mammalian cytosolic NADP+-dependent malic enzyme cDNA, especially within the four functional domains. Two major bands at 3.7 and 2.4 kb were detected on Northern blots containing the RNA from 25 tissues from fetuses and adult pigs. A high expression level was found in the adrenal gland, muscle, liver, and peripheral nerves. The analysis of malic enzyme RFLPs in five SLA informative families revealed an independent segregation of the ME1 gene from the SLA region. In situ hybridization results localized the cytosolic malic enzyme on the swine Chromosome (Chr) 1p1.2, except that the association between SLA and the malic enzyme activity level was due to a physical genetic linkage. Thus, the mechanisms underlying this association remain to be elucidated.

Ipomeanol analogs as chemopreventive agents: effect on the in vitro metabolism of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK)

4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) is a tobacco-specific, powerful, organospecific lung carcinogen. 4-Ipomeanol (IPO) is an investigational chemotherapeutic drug with specific toxicity towards the lung. We hypothesized that non-toxic analogs of IPO could be competitive inhibitors of the metabolic activation of NNK. We had shown previously that 4-hydroxy-1-phenyl-1-pentanone (HPP) and 7-hydroxy-1-phenyl-1-octanone (4-HPO) are effectively inhibiting the lung tumor activity of NNK in A/J mice. In these extended studies we have synthesized 11 new analogs of HPP and tested them for their in vitro activities as inhibitors of the metabolism of NNK. The present study demonstrated that the lipophilicity in the molecule is playing an important role for the inhibition of NNK metabolism with pulmonary and hepatic microsomes of A/J mice.

The BAT1 gene in the MHC encodes an evolutionarily conserved putative nuclear RNA helicase of the DEAD family

The BAT1 gene has previously been identified about 30 kb upstream from the tumor necrosis factor (TNF) locus and close to a NF kappa b-related gene of the nuclear factor family in the major histocompatibility complex (MHC) of human, mouse, and pig. We now show that the BAT1 translation product is the homolog of the rat p47 nuclear protein, the WM6 Drosophila gene product, and probably also Ce08102 of Caenorhabditis elegans, all members of the DEAD protein family of ATP-dependent RNA helicases. This family has more than 40 members, including the eukaryotic translation initiation factor-4A (eIF-4A), the human nuclear protein p68, and the Drosophila oocyte polar granule component vasa. BAT1 spans about 10 kb, is split into 10 exons of varying length, and encodes a protein of 428 amino acids (approximately 48 kDa). Human and pig BAT1 cDNAs display 95.6% identity in the coding region and 80% identity in the 5' and 3' noncoding regions. Several repeat sequences of different types were identified in introns of the porcine BAT1 gene. Three different mRNAs, 4.1, 1.7, and 0.9 kb, respectively, were detected in all tissues analyzed upon hybridization with porcine BAT1 cDNA. Transfection and expression of human BAT1 cDNA after tagging with a heterologous antibody recognition epitope revealed a nuclear localization of the hybrid protein. An MspI RFLP was detected in an SLA class I typed family, confirming the localization of the BAT1 gene in the porcine MHC. BAT1 thus encodes a putative nuclear ATP-dependent RNA helicase and is likely to have an indispensable function.

Characterization of six new loci within the swine major histocompatibility complex class III region

A search for new potential coding sequences was conducted within two overlapping cosmid genomic DNA clusters of about 170 and 45 kb from the swine major histocompatibility complex class III region. The sequences were detected with various probes, including pools of swine cDNA, homologous and heterologous genomic sequences, and synthetic oligonucleotides. The 170 kb cluster was centered on the tumor necrosis factor genes (TNF), and the 45 kb cluster contained the heat-shock protein 70 genes (HSP70). The TNF cluster revealed the presence of five new genes: lymphotoxin beta, BAT1, BAT2, BAT3, and a sequence related to DNA-binding factors. No sequence homologous to B144 was found in the TNF cluster, although other unidentified coding sequences may be present in this cluster. The HSP70 cluster contained a gene identified as BAT6, that is, tRNA-valyl synthetase. These results provide new evidence that the genomic maps of these various genes in the TNF and HSP70 sub-regions are similar in swine and human.

Physical mapping of the split hand/split foot locus on chromosome 7 and implication in syndromic ectrodactyly

Split hand/split foot (ectrodactyly; SHSF) is a human developmental malformation characterized by missing digits and claw-like extremities. An autosomal dominant form of this disorder has been mapped to 7q21.3-q22.1; the locus has been designated SHFD1. We have constructed a physical map consisting of overlapping yeast artificial chromosome clones for the entire region. Somatic cell hybrid and fluorescent in situ hybridization analyses were used to define SHSF-associated chromosomal rearrangements in twelve patients. An SHFD1 critical interval of 1.5 Mb was established by analysis of five patients with deletions. Translocation or inversion breakpoints found in six patients were mapped within 700 kb of each other in the critical region. Of note is that eight of the patients analyzed (67%) are in fact classified as having syndromic ectrodactyly. Thus, these mapping data establish a relationship between simple split hand/split foot and this more complex group of human birth defects. Finally, we have mapped DLX5, a member of the Distal-less homeobox gene family, to the SHFD1 critical interval.

Fine mapping of the autosomal dominant split hand/split foot locus on chromosome 7, band q21.3-q22.1

Split hand/split foot (SHFD) is a human developmental defect characterized by missing digits, fusion of remaining digits, and a deep median cleft in the hands and feet. Cytogenetic studies of deletions and translocations associated with this disorder have indicated that an autosomal dominant split hand/split foot locus (gene SHFD1) maps to 7q21-q22. To characterize the SHFD1 locus, somatic cell hybrid lines were constructed from cytogenetically abnormal individuals with SHFD. Molecular analysis resulted in the localization of 93 DNA markers to one of 10 intervals surrounding the SHFD1 locus. The translocation breakpoints in four SHFD patients were encompassed by the smallest region of overlap among the SHfD-associated deletions. The order of DNA markers in the SHFD1 critical region has been defined as PON-D7S812-SHFD1-D7S811-ASNS. One DNA marker, D7S811, detected altered restriction enzyme fragments in three patients with translocations when examined by pulsed-field gel electrophoresis (PFGE). These data map SHFD1, a gene that is crucial for human limb differentiation, to a small interval in the q21.3-q22.1 region of human chromosome 7.

[Management of tricuspid atresia in neonates. Report of three cases and review of literature]

The present article describes the management of three neonates with tricuspid atresia and duct dependent pulmonary circulation referred to the Instituto de Coração de Pernambuco in November 1992. A brief literature review of the condition is added. Full diagnosis was established with echocardiography at the neonatal ICU; all of them were intubated, mechanically ventilated and started on PGE1 and Dopamine infusions. Within 10h to 24h of hospitalization, all were submitted to surgery. One patient died on the third postoperative day the other two were discharged in good clinical condition. Despite the small our experience shows that clinical and surgical management of tricuspid atresia with duct dependent pulmonary circulation can reach satisfactory results in our region providing that early diagnosis of cyanotic heart disease is established by the pediatrician with timely transferal of the neonate to a reference center in paediatric cardiology.

Isolation of four HSP70 genes in the pig and localization on chromosomes 7 and 14

For insight into the general organization of the swine leukocyte antigen (SLA) complex, the swine major histocompatibility complex (MHC), four sequences related to the heat-shock proteins HSP70 were characterized by screening of a pig genomic cosmid library with a swine cDNA HSP70 2.6-kb probe. This yielded three positive clones: HC2.2, HC3.2, and HC4.2. Restriction site maps revealed a large overlap of HC2.2 with HC3.2, whereas HC4.2 was independent. Southern blot hybridization with the 5' section, the central section, and the 3' section of the 2.6-kb probe and also with a swine 4.5-kb HSP70 genomic probe suggested the existence, within the overlapping clones, of three distinct HSP70 sequences encompassing a segment no longer than 22 kb. The HC4.2 clone, which hybridized with the same probes, displayed a single band of 7.3 kb, probably corresponding to one gene only. Fluorescent in situ hybridization on swine chromosome metaphases with the whole HC2.2 or HC4.2 cosmids allowed the assignment of HC2.2 to MHC region on Chromosome (Chr) 7 (Cen-p1.1), and of HC4.2 to Chr 14 (q2.4-2.5). Thus, as in humans, the swine MHC comprises three closely linked HSP70 loci. The presence of additional genes belonging to the same inducible HSP70 gene family can be expected from what is known in humans. The HSP70 gene found here on the pig Chr 14 may be one of these putative unidentified genes.

[Evaluation of interests, experiences and chemistry knowledge among students admitted to the Lisboa Medical School en 1989/1990]

Selected medical students for undergraduate medical courses in Portugal exhibit each year substantial deficiencies in chemistry. The group of students admitted to the Faculty of Medicine of Lisbon in 1989/1990 were selected by admission criteria apparently more restrictive than before. The aim of this study was to evaluate the quality of the theoretical knowledge in chemistry showed by those students before learning biochemistry. Eight-four of the admitted students were invited to participate in the study, by replying to an anonymous questionnaire on chemistry. A second questionnaire to identify a variety of personal/social factors was completed by the same students some days later. The results obtained have confirmed a clearly insufficient chemical background, in spite of the high scores achieved by those students in chemistry and other science subjects on the application. The majority of the students here studied declared financial security, live with their families, study at home, and report scarce outside distractions. It may be concluded that the new admission criteria to the faculties of medicine do not select students with better academic performances on chemistry than before. Otherwise, the sociocultural characteristics of the entrants do not fulfill the expectations that could contrast them clearly with average groups of students.

Retrieval effects of both post- and presession beta-endorphin administration in a three-session paradigm

Rats were submitted to three sessions, with a 24-hr interval between, of step-down inhibitory avoidance task using a 60-Hz, 0.3-mA footshock, or of two-way active avoidance task using 25 presentations of a 5-sec. 1-kHz tone and a 0.4-mA footshock. Animals received intraperitoneal injections of either saline or beta-endorphin (2.0 microgram/kg) after the first session, and before the second or the third sessions, in a 2 x 2 x 2 design. beta-Endorphin given before the second or the third sessions improved retention for both tasks, but when administered after the first session, it impaired retention for the second session. The administration of beta-endorphin after the first session prevented the retrieval enhancement by the opioid given before the third session. Rats receiving beta-endorphin both after the first and before the second sessions, whilst showing no retrieval impairment on the second session, also did not show the pre-third session beta-endorphin retrieval enhancing effect. These data suggest that the post-first session exaggeration of the endogenous opioid state by beta-endorphin administered after the first session causes a long-lasting change in retrievability for the active and inhibitory avoidance tasks, as shown by the lack of the retrieval enhancing effect of beta-endorphin given before the third session.