The improvement of crop yield in marginal environments using 'on-farm' seed priming: nodulation, nitrogen fixation and disease resisitance

On-farm seed priming with water is a low-cost, low-risk technology that is easily adopted by resource-poor farmers. It increases the yield of tropical and subtropical annual crops in marginal areas by a combination of better crop establishment and improved individual plant performance. The effects of seed priming, i.e. soaking seeds overnight in water before sowing, on plant growth and development are consequences of faster germination, emergence, and more vigorous early growth. Results from in-vitro, on-station and on-farm experiments are discussed. Recent work has tested opportunities for resource-poor farmers to use seed priming as a vehicle for applying biofertilisers (Rhizobia). Preliminary results from field experiments suggest that these interventions are very effective over and above the already demonstrated benefits of priming with water alone. In a pot experiment using chickpea, combining a Rhizobium inoculation with seed priming significantly increased nodulation but had little effect on yield. Nevertheless, the results confirmed that Rhizobium inoculation is compatible with on-farm seed priming. Observations in the field have shown that some primed crops show enhanced resistance to disease, either as a consequence of increased vigour, altered phenology, or due to some more fundamental mechanism associated with exposure of seeds to anaerobic conditions during priming. Priming seeds of a highly susceptible cultivar of pearl millet in water for 8 h before sowing significantly reduced the incidence of downy mildew in artificially infected seedlings from 80% to less than 60%.

Eosinophils in a tri-cell multicellular tumor spheroid (MTS)/endothelium complex

Eosinophils have been found in infiltrates of many different cancers. It is still unclear as to whether they are passive bystanders in the cellular milieu or active cellular agents in host responses. Thus their harmful or helpful nature remains equivocal. We have developed an in vitro tri-cell model of eosinophils, MCF-7 breast tumor cell spheroids and HUVEC endothelial cells to examine the binding and association of eosinophils with both the tumor and the endothelia and the ensuing action of the tumor. Eosinophils bound very rapidly to the tumor spheroid and remained tightly bound throughout the 24 hr culture period. Histological staining of the tri-cell complex revealed highly granulated eosinophils as well as large amounts of degranulated protein diffused throughout the spheroid. IL-5 treatment of eosinophil: MTS complexes resulted in destruction of the tumor cells, particularly those which had grown out from the spheroid onto the endothelial cells. Eosinophils, pretreated with IL-5 before interaction with the tumor or endothelial cells, bound aggressively to the endothelial cells, thereby preventing tumor attachment. This eosinophil tri-cell tumor model system mimics clinical observations with regards to binding to epithelial and endothelial cells, dispersal of granular proteins throughout the tumor and also tumor destruction. Because it closely mirrors in vivo cellular interactions, it allows one to study more closely the mechanism(s) of eosinophil killing, the modulation of eosinophil activity and the testing of therapeutic interventions. The accommodation of the model to tumor invasion, using metastatic tumor cells and extracellular matrices such as matrigel, will help to elucidate a role for eosinophils (and their mediators) in cancer invasion and metastasis.

Five-year results of a new total replacement prosthesis for the finger metacarpo-phalangeal joints

An unconstrained surface metacarpophalangeal joint replacement was developed with metal metacarpal and polyethylene phalangeal components, fixed by uncemented finned polyethylene plugs which allowed some metacarpal component motion. Clinical and radiological results in 13 joints in eight patients are presented after 5 years. One infection required revision at 3 months. There were no further complications. At final review there were no implant failures. Two of 13 joints showed lucency around the phalangeal component and one showed 2mm subsidence of the metacarpal component. No other adverse radiological features were observed. Seven patients had no pain and one had minor discomfort. Joint movement had improved from an arc of 27 degrees to 60 degrees and disability, assessed using the P.E.M. questionnaire, had improved from 77% to 9%.

Sequence of Plasmodium falciparum chromosomes 1, 3-9 and 13

Since the sequencing of the first two chromosomes of the malaria parasite, Plasmodium falciparum, there has been a concerted effort to sequence and assemble the entire genome of this organism. Here we report the sequence of chromosomes 1, 3-9 and 13 of P. falciparum clone 3D7--these chromosomes account for approximately 55% of the total genome. We describe the methods used to map, sequence and annotate these chromosomes. By comparing our assemblies with the optical map, we indicate the completeness of the resulting sequence. During annotation, we assign Gene Ontology terms to the predicted gene products, and observe clustering of some malaria-specific terms to specific chromosomes. We identify a highly conserved sequence element found in the intergenic region of internal var genes that is not associated with their telomeric counterparts.

High-speed plasmid isolation using 96-well, size-exclusion filter plates

The accelerating pace of genomics analysis has necessitated the abbreviation of DNA sample preparation protocols. We have developed a size-exclusion-based system for the rapid isolation ofplasmid DNA in a 96-well microplate format. This high-speed protocol employs a modified alkaline lysis methodfor the preparation of the bacterial lysate, followed by three short vacuum filtration steps. Unlike traditional bind/wash/elute methods, there is no need to use chaotropic salts or ethanol. The samples are recovered from the top side of the MultiScreen96 PLASMID plates. Starting with bacterial cell pellets, the entire prycedure for purifying the plasmid DNA can be performed in 30 min with a multichannel pipettor. The high yields, reproducibility, and quality of the plasmids make this system a good choice for any cloning or DNA sequencing operation.

The genome sequence of Schizosaccharomyces pombe

We have sequenced and annotated the genome of fission yeast (Schizosaccharomyces pombe), which contains the smallest number of protein-coding genes yet recorded for a eukaryote: 4,824. The centromeres are between 35 and 110 kilobases (kb) and contain related repeats including a highly conserved 1.8-kb element. Regions upstream of genes are longer than in budding yeast (Saccharomyces cerevisiae), possibly reflecting more-extended control regions. Some 43% of the genes contain introns, of which there are 4,730. Fifty genes have significant similarity with human disease genes; half of these are cancer related. We identify highly conserved genes important for eukaryotic cell organization including those required for the cytoskeleton, compartmentation, cell-cycle control, proteolysis, protein phosphorylation and RNA splicing. These genes may have originated with the appearance of eukaryotic life. Few similarly conserved genes that are important for multicellular organization were identified, suggesting that the transition from prokaryotes to eukaryotes required more new genes than did the transition from unicellular to multicellular organization.

Recovery of zeta-chain expression and changes in spontaneous IL-10 production after PSA-based vaccines in patients with prostate cancer

Circulating T lymphocytes of patients with prostate cancer have been reported to have functional deficits, including low or absent zeta-chain expression. To determine whether these functional impairments could be reversed by prostate specific antigen-based vaccination therapy, 10 patients treated with recombinant human prostate specific antigen plus GM-CSF and eight others receiving prostate specific antigen plus oil emulsion in two pilot clinical trials were evaluated prior to and after vaccination for several immunologic end points, including zeta-chain expression and cytokine production by circulating T cells as well as the frequency of T cells able to respond to prostate specific antigen in ELISPOT assays. The flow cytometry assay for zeta-chain expression was standardized to allow for a reliable comparison of pre- vs post-vaccination samples. Prior to therapy, the patients were found to have significantly lower zeta-chain expression in circulating CD3(+) cells and a higher percentage of zeta-chain negative CD3(+) and CD4(+) cells than normal donors. The patients' peripheral blood mononuclear cells spontaneously produced more IL-10 ex vivo than those of normal controls. After vaccination, recovery of zeta-chain expression was observed in 50% of patients in both clinical trials. Also, spontaneous IL-10 secretion by peripheral blood mononuclear cells decreased following immunotherapy in patients treated with prostate specific antigen and GM-CSF. The frequency of prostate specific antigen-reactive T cells was detectable in 7 out of 18 patients vs 4 out of 18 patients prior to vaccination. Only one of 18 patients was a clinical responder. The vaccine had stimulatory effects on the patients' immune system, but post-vaccine immune recovery could not be correlated to progression-free survival in this small cohort of patients with prostate cancer.

End-to-end performance measurement of Internet based medical applications

We present a method to obtain an end-to-end characterization of the performance of an application over a network. This method is not dependent on any specific application or type of network. The method requires characterization of network parameters, such as latency and packet loss, between the expected server or client endpoints, as well as characterization of the application's constraints on these parameters. A subjective metric is presented that integrates these characterizations and that operates over a wide range of applications and networks. We believe that this method may be of wide applicability as research and educational applications increasingly make use of computation and data servers that are distributed over the Internet.

The decaying genome of Mycobacterium leprae

Everything that we need to know about Mycobacterium leprae, a close relative of the tubercle bacillus, is encrypted in its genome. Inspection of the 3.27 Mb genome sequence of an armadillo-derived Indian isolate of the leprosy bacillus identified 1,605 genes encoding proteins and 50 genes for stable RNA species. Comparison with the genome sequence of Mycobacterium tuberculosis revealed an extreme case of reductive evolution, since less than half of the genome contains functional genes while inactivated or pseudogenes are highly abundant. The level of gene duplication was approximately 34% and, on classification of the proteins into families, the largest functional groups were found to be involved in the metabolism and modification of fatty acids and polyketides, transport of metabolites, cell envelope synthesis and gene regulation. Reductive evolution, gene decay and genome downsizing have eliminated entire metabolic pathways, together with their regulatory circuits and accessory functions, particularly those involved in catabolism. This may explain the unusually long generation time and account for our inability to culture the leprosy bacillus.

Differentiation between bone infarction and acute osteomyelitis in children with sickle-cell disease with use of sequential radionuclide bone-marrow and bone scans

BACKGROUND

The differentiation of bone infarction from acute osteomyelitis in patients with sickle-cell disease is challenging, as the clinical presentations of the two conditions are similar and imaging and laboratory studies are of limited value.

METHODS

A combination of radionuclide bone-marrow and bone scans was performed sequentially within a twenty-four-hour period (with one exception) to aid in the differentiation between bone infarction and osteomyelitis in seventy-nine consecutive episodes of acute bone pain in children with sickle-cell disease.

RESULTS

Seventy cases of bone infarction were diagnosed on the basis of decreased uptake on the bone-marrow scan and abnormal uptake on the bone scan at the site of pain. Antibiotic administration was discontinued in sixty-six of the seventy cases after the imaging results were obtained, and the bone pain resolved. In four of the seventy-nine cases, there was normal uptake on the bone-marrow scan and abnormal uptake on the bone scan at the site of pain, findings that were suggestive of acute osteomyelitis. In three of these cases, osteomyelitis was proven by culture, and the symptoms in all four resolved with antibiotic treatment. In five of the seventy-nine cases, the bone-marrow and bone scans were normal and thought to indicate neither osteomyelitis nor bone infarction; in all of these cases, the symptoms resolved without the use of antibiotics.

CONCLUSIONS

These findings suggest that osteomyelitis can be differentiated from bone infarction in children with sickle-cell anemia and acute bone pain by a combination of sequential bone-marrow and bone scintigraphy.

WP744, a novel anthracycline with enhanced proapoptotic and antileukemic activity

BACKGROUND

MDR1 or MRP1 drug resistance mechanisms seriously limit the efficacy of anthracyclines such as doxorubicin, in the treatment of acute myeloid leukemia (AML). Our studies indicated that reducing basicity, increasing steric hindrance at C-4', and/or lipophilicity may help circumvent P-glycoprotein (P-gp)-mediated anthracycline efflux and thus increase drug retention in MDR-positive cells. From a series of 4'-substituted analogs, 4'-O-benzylated doxorubicin (WP744) was selected for a comparison with the classic anthracycline doxorubicin for their cytotoxic and pro-apoptotic properties. WP744 retains cytotoxic activity against P-gp and MRP-positive cells.

METHODS AND RESULTS

In three AML cell lines (K562, KBM-3, and OCIM2) WP744 was markedly more potent (IC50 values of 0.18, <0.05, and <0.05 microg/ml, respectively) than doxorubicin (IC50 values of >0.5, 0.07, and 0.09 microg/ml, respectively). Likewise, WP744 inhibited the colony formation by AML-CFU cells from fresh bone marrow of three AML patients more strongly than doxorubicin. Cell growth inhibition by WP744 is accompanied by apoptosis induction as shown by TUNEL assay in OCIM2 cells. WP744-induced apoptosis appears to be mediated by caspase-3 as apoptotic changes were abrogated in the presence of the caspase 3 inhibitor Z-DEVD-FMK. Accordingly, caspase 3 activity was elevated in the lysates from drug-treated cells. WP744 induced also cleavage of apoptotic marker poly(ADP-ribose)polymerase (PARP). Finally, WP744 at 0.05 microM and greater was a potent inducer of apoptosis (by quantitative DNA fragmentation) in cultured human acute lymphoblastic leukemia (ALL) CEM cells, compared to 0.5 microM doxorubicin needed for a similar effect.

CONCLUSION

The novel anthracycline WP744 was found to be an antileukemic agent with proapoptotic activity superior to that of doxorubicin.

Therapeutic targeting of the MEK/MAPK signal transduction module in acute myeloid leukemia

The mitogen-activated protein kinase (MAPK) pathway regulates growth and survival of many cell types, and its constitutive activation has been implicated in the pathogenesis of a variety of malignancies. In this study we demonstrate that small-molecule MEK inhibitors (PD98059 and PD184352) profoundly impair cell growth and survival of acute myeloid leukemia (AML) cell lines and primary samples with constitutive MAPK activation. These agents abrogate the clonogenicity of leukemic cells but have minimal effects on normal hematopoietic progenitors. MEK blockade also results in sensitization to spontaneous and drug-induced apoptosis. At a molecular level, these effects correlate with modulation of the expression of cyclin-dependent kinase inhibitors (p27(Kip1) and p21(Waf1/CIP1)) and antiapoptotic proteins of the inhibitor of apoptosis proteins (IAP) and Bcl-2 families. Interruption of constitutive MEK/MAPK signaling therefore represents a promising therapeutic strategy in AML.

Is breaking up hard to do? Breakage, growth, and survival in the parasitic clonal plant Cuscuta corymbosa (Convolvulaceae)

In a tripartite exploration of the effects of traumatic breakage in the parasitic clonal plant Cuscuta corymbosa, experimental breakage had significant negative effects upon stem extension of ramets distal to a break and the level of that effect depended upon the number of ramets in the severed fragment. Regular monitoring of clonal individuals transplanted onto naturally occurring, native host species revealed that breakage in individuals growing under natural conditions ranged from 2 to 66% of all interramet connections and significantly affected distance between ramets and stolon generation in ramets associated with a break. Simulations revealed that these responses to breakage would significantly change the "shape" of a clonal individual in a manner capable of affecting probabilities of encounter with patchily distributed resources. Nonetheless, the observed levels of breakage had no discernible effect on biomass accumulation, although individuals that survived into the dry season and thus gained the potential to reproduce in additional seasons had a significantly lower rate of breakage than those that did not. We suggest that the lack of a relationship between breakage and within-season biomass accumulation is an indication that parasite response to breakage is gauged to expected levels of breakage for the habitat. We note that the capacity of ramets to survive disconnection significantly decreased the loss of tissue that would occur if subunits did not possess the potential to function independently.

Mechanism of GnRH receptor signaling on gonadotropin release and gene expression in pituitary gonadotrophs

Gonadotropin releasing hormone (GnRH), the first key hormone of reproduction, is synthesized and secreted from the hypothalamus in a pulsatile manner and stimulates pituitary gonadotrophs (5-10% of the pituitary cells) to synthesize and release gonadotropin luteinizing hormone (LH) and follicle stimulating hormone (FSH). Gonadotrophs consist of 60% multihormonal cells (LH+FSH) and 18% LH- and 22% FSH-containing cells. LH and FSH, members of the glycoprotein hormone family, stimulate spermatogenesis, folliculogenesis, and ovulation. Although GnRH plays a pivotal role in gonadotropin synthesis and release, other factors such as gonadal steroids and gonadal peptides exert positive and negative feedback mechanisms, which affect GnRH actions. GnRH actions include activation of phosphoinositide turnover as well as phospholipase D and A2, mobilization and influx of Ca2+, activation of protein kinase C (PKC) and mitogen-activated protein kinase (MAPK). A complex crosstalk between the above messenger molecules mediates the diverse actions of GnRH. Understanding the signaling mechanisms involved in GnRH actions is the basis for our understanding of basic reproductive functions in general and gonadotropin synthesis and release in particular.

Self-reported marijuana effects and characteristics of 100 San Francisco medical marijuana club members

In order to assess the relationships between medical marijuana users' reasons for use, side effects, and drug use patterns, 100 participants were recruited from the San Francisco Cannabis Cultivator's Club. Users, averaging 14 years pre-illness use, perceived marijuana to be more effective than other treatments and to have less severe side effects. Urine drug assays showed recent use of other drugs, particularly stimulants. History of substance abuse or dependence and other psychiatric disorders was common. Those with greater past dependence on other drugs thought marijuana to be more effective but also reported worse side effects and quality of life. Quality of life was associated more with marijuana side effects rating than effectiveness. Patients reported potentially serious marijuana side effects on some questionnaires but not others. Inconsistencies in reporting made interpretation of results difficult. Physician supervision of medical marijuana use would allow more effective monitoring of therapeutic and unwanted effects, some unrecognized by patients.

From first base: the sequence of the tip of the X chromosome of Drosophila melanogaster, a comparison of two sequencing strategies

We present the sequence of a contiguous 2.63 Mb of DNA extending from the tip of the X chromosome of Drosophila melanogaster. Within this sequence, we predict 277 protein coding genes, of which 94 had been sequenced already in the course of studying the biology of their gene products, and examples of 12 different transposable elements. We show that an interval between bands 3A2 and 3C2, believed in the 1970s to show a correlation between the number of bands on the polytene chromosomes and the 20 genes identified by conventional genetics, is predicted to contain 45 genes from its DNA sequence. We have determined the insertion sites of P-elements from 111 mutant lines, about half of which are in a position likely to affect the expression of novel predicted genes, thus representing a resource for subsequent functional genomic analysis. We compare the European Drosophila Genome Project sequence with the corresponding part of the independently assembled and annotated Joint Sequence determined through "shotgun" sequencing. Discounting differences in the distribution of known transposable elements between the strains sequenced in the two projects, we detected three major sequence differences, two of which are probably explained by errors in assembly; the origin of the third major difference is unclear. In addition there are eight sequence gaps within the Joint Sequence. At least six of these eight gaps are likely to be sites of transposable elements; the other two are complex. Of the 275 genes in common to both projects, 60% are identical within 1% of their predicted amino-acid sequence and 31% show minor differences such as in choice of translation initiation or termination codons; the remaining 9% show major differences in interpretation.

A superfamily of variant genes encoded in the subtelomeric region of Plasmodium vivax

The malarial parasite Plasmodium vivax causes disease in humans, including chronic infections and recurrent relapses, but the course of infection is rarely fatal, unlike that caused by Plasmodium falciparum. To investigate differences in pathogenicity between P. vivax and P. falciparum, we have compared the subtelomeric domains in the DNA of these parasites. In P. falciparum, subtelomeric domains are conserved and contain ordered arrays of members of multigene families, such as var, rif and stevor, encoding virulence determinants of cytoadhesion and antigenic variation. Here we identify, through the analysis of a continuous 155,711-base-pair sequence of a P. vivax chromosome end, a multigene family called vir, which is specific to P. vivax. The vir genes are present at about 600-1,000 copies per haploid genome and encode proteins that are immunovariant in natural infections, indicating that they may have a functional role in establishing chronic infection through antigenic variation.

Gene discovery in Plasmodium chabaudi by genome survey sequencing

The first genome survey sequencing of the rodent malaria parasite Plasmodium chabaudi is presented here. In 766 sequences, 131 putative gene sequences have been identified by sequence similarity database searches. Further, 7 potential gene families, four of which have not previously been described, were discovered. These genes may be important in understanding the biology of malaria, as well as offering potential new drug targets. We have also identified a number of candidate minisatellite sequences that could be helpful in genetic studies. Genome survey sequencing in P. chabaudi is a productive strategy in further developing this in vivo model of malaria, in the context of the malaria genome projects.

Stimulant psychosis: symptom profile and acute clinical course

Nineteen patients seen at a psychiatric emergency service with amphetamine- or cocaine-induced psychotic disorder were assessed with structured interviews, chart review, and blood and urine testing. All had a predominance of positive symptoms from the Positive and Negative Syndrome Scale (PANSS). However, some subjects had substantial Negative Scale scores (26%), bizarre delusions (95%), and Schneiderian hallucinations (63%), mimicking a broad range of schizophrenic symptoms. Several PANSS scores were correlated with treatment intensity: Positive score with seclusion hours, General Psychopathology and Negative scores with hospitalization length, and General Psychopathology score with neuroleptic dose. Presenting symptoms may help in treatment planning.

Massive gene decay in the leprosy bacillus

Leprosy, a chronic human neurological disease, results from infection with the obligate intracellular pathogen Mycobacterium leprae, a close relative of the tubercle bacillus. Mycobacterium leprae has the longest doubling time of all known bacteria and has thwarted every effort at culture in the laboratory. Comparing the 3.27-megabase (Mb) genome sequence of an armadillo-derived Indian isolate of the leprosy bacillus with that of Mycobacterium tuberculosis (4.41 Mb) provides clear explanations for these properties and reveals an extreme case of reductive evolution. Less than half of the genome contains functional genes but pseudogenes, with intact counterparts in M. tuberculosis, abound. Genome downsizing and the current mosaic arrangement appear to have resulted from extensive recombination events between dispersed repetitive sequences. Gene deletion and decay have eliminated many important metabolic activities including siderophore production, part of the oxidative and most of the microaerophilic and anaerobic respiratory chains, and numerous catabolic systems and their regulatory circuits.

Imaging and clinical characteristics of focal atrophy of segments 2 and 3 in primary sclerosing cholangitis

BACKGROUND AND AIMS

Focal atrophy in primary sclerosing cholangitis (PSC) is usually thought to result from severe biliary stricture and focal biliary cirrhosis. Atrophy of the left lateral segments (segments 2 and 3) are striking when observed grossly. This type of atrophy may be subtle on cross-sectional imaging and by endoscopic retrograde cholangiopancreatography (ERCP) because of the peripheral location and compensatory hypertrophy of other parts of the liver. We examined 44 consecutive PSC patients to determine the incidence and clinical characteristics of this abnormality, and to correlate imaging studies with the gross appearance.

METHODS

We reviewed all cases of PSC encountered over a 3 year period ascertained from the liver disease registry. Magnetic resonance imaging or CT images were re-examined for evidence of segment 2 and 3 atrophy.

RESULTS

Four of 44 patients had focal segment 2 and 3 atrophy. These four had been confirmed laparoscopically or by inspection of the liver explant. The remaining segments of the liver were relatively spared of injury in two of the patients, and three of the four patients had preserved synthetic function without evidence of portal hypertension. While the abnormality is clearly visible on cross-sectional imaging, its peripheral location caused it to be an unobtrusive. Likewise, ERCP did not clearly reveal the abnormality on initial inspection.

CONCLUSIONS

We conclude that focal atrophy of segments 2 and 3 is a sometimes early and subtle finding in PSC that may be overlooked in cross-sectional imaging or ERCP unless specifically sought.

Calculation of the electronic structure and spectra of model cytochrome P450 compound I

The electronic structure and spectra of the oxyferryl (Fe=O) compound I P450 heme species, the transient putative active intermediate of cytochrome P450s, have been calculated employing a full protoporphyrin IX heme model representation. The principal aim of this work was to compare the computed spectra of this species with the observed transient spectra attributed to it. Computations were made using both nonlocal density functional theory (DFT) and semiempirical INDO/CI methods to characterize the electronic structure of the compound I P450 species. Both methods resulted in a similar antiferromagnetic doublet as the ground state with a ferromagnetic quartet excited state partner, slightly higher in energy. The INDO/ROHF/CI semiempirical method was used to calculate the spectrum of the protoporphyrin IX P450 compound I heme species in its lowest energy antiferromagnetic doublet state at the DFT optimized geometry. As a reference, the spectrum of the ferric resting form of the protoporphyrin IX P450 heme species was also calculated. The computed shifts in the Soret and Q bands of compound I relative to the resting state were both in good agreement with the corresponding experimentally observed shifts in the transient spectra of cytochrome P450cam (Biochem. Biophys. Res. Commun. 201 (1994) 1464) and chloroperoxidase (Biochem. Biophys. Res. Commun. 94 (1980) 1123) both ascribed to their common compound I heme site. This consistency provides additional, independent support for the assignment of compound I as the origin of the reported observed transient spectra.

Evaluating a telemedicine system to assist in the management of dermatology referrals

BACKGROUND

Teledermatology systems fall into two categories: live video or store-and-forward. In the former, video-conferencing equipment is used to connect a patient with a remote consultant. This method has been evaluated as an aid to dermatology, but it is expensive both in terms of capital and running costs. Video consultations are generally longer than conventional ones and harder to schedule. Some authors have considered store-and-forward as an alternative to live video: instead of a consultation, specialists could make a rapid inspection of a transmitted still image.

OBJECTIVES

A study was conducted to evaluate the role of telemedicine in the dermatology outpatients department of a district general hospital (Whittington Hospital NHS Trust, London, U.K.).

METHODS

One hundred and ninety-four patients were seen by one of two consultant dermatologists. A nurse used a video camera to store digital images of each patient's problem and compiled a history from the GP's referral letter. The images were reviewed 13 months later by both dermatologists; they recorded a provisional diagnosis and an assessment of how urgent an appointment would have been made given the information provided by the system. A third consultant graded the level of agreement between the telemedicine diagnoses and the face-to-face consultations.

RESULTS

High levels of agreement were found between the diagnoses of the dermatologists using the system to inspect images and those of the dermatologist who saw the patients (77%). Consultants using the system recommended fewer urgent appointments (32% compared with 64%) and felt that in 31% of cases the patient did not need to be seen. In 15% of these cases (5% of the total), however, their diagnosis differed significantly from that of the consultant who saw the patient. Had the system been in use, 14% of patients conventionally assigned a non-urgent appointment would have been seen urgently.

CONCLUSIONS

The images allowed a reasonably accurate diagnosis. The software was not reliable (six cases could not be viewed), or easy to use (it took approximately an hour to view 20 cases) but an improved version could be used in triaging outpatient appointments.

Prevalence of small inversions in yeast gene order evolution

Gene order evolution in two eukaryotes was studied by comparing the Saccharomyces cerevisiae genome sequence to extensive new data from whole-genome shotgun and cosmid sequencing of Candida albicans. Gene order is substantially different between these two yeasts, with only 9% of gene pairs that are adjacent in one species being conserved as adjacent in the other. Inversion of small segments of DNA, less than 10 genes long, has been a major cause of rearrangement, which means that even where a pair of genes has been conserved as adjacent, the transcriptional orientations of the two genes relative to one another are often different. We estimate that about 1,100 single-gene inversions have occurred since the divergence between these species. Other genes that are adjacent in one species are in the same neighborhood in the other, but their precise arrangement has been disrupted, probably by multiple successive multigene inversions. We estimate that gene adjacencies have been broken as frequently by local rearrangements as by chromosomal translocations or long-distance transpositions. A bias toward small inversions has been suggested by other studies on animals and plants and may be general among eukaryotes.

Both the structure and DNA binding function of the barrier-to-autointegration factor contribute to reconstitution of HIV type 1 integration in vitro

Retroviral integration is mediated by viral preintegration complexes (PICs), and human immunodeficiency virus type 1 (HIV-1) PICs treated with high salt lose their in vitro integration activity. Barrier-to-autointegration factor (BAF) is a host protein that efficiently restores PIC activity, but the mechanism(s) by which BAF participates in HIV-1 integration remains largely unknown. Here we developed a gel shift assay to study BAF DNA binding, and analyzed 14 mutant proteins containing substitutions of conserved residues for binding and PIC reconstitution activities. Although wild-type BAF efficiently bound double-stranded DNA, binding to single-stranded DNA, RNA, or an RNA/DNA hybrid was not detected, suggesting that BAF associates with retroviral cDNA relatively late during reverse transcription. Although some of the BAF mutant proteins efficiently bound DNA, others were defective for binding. Mutants that bound DNA efficiently reconstituted HIV-1 integration, even though in one case binding was just 0.2% of wild-type BAF. Although misfolded mutants did not reconstitute integration, a structurally intact DNA binding-defective mutant displayed partial activity at high BAF concentration. We therefore conclude that both BAF protein structure and its DNA binding activity play roles in reconstituting HIV-1 integration in vitro.

Effects of agronomic treatments on structure and function of ammonia-oxidizing communities

The aim of this study was to determine the effects of different agricultural treatments and plant communities on the diversity of ammonia oxidizer populations in soil. Denaturing gradient gel electrophoresis (DGGE), coupled with specific oligonucleotide probing, was used to analyze 16S rRNA genes of ammonia oxidizers belonging to the beta subgroup of the division Proteobacteria by use of DNA extracted from cultivated, successional, and native deciduous forest soils. Community profiles of the different soil types were compared with nitrification rates and most-probable-number (MPN) counts. Despite significant variation in measured nitrification rates among communities, there were no differences in the DGGE banding profiles of DNAs extracted from these soils. DGGE profiles of DNA extracted from samples of MPN incubations, cultivated at a range of ammonia concentrations, showed the presence of bands not amplified from directly extracted DNA. Nitrosomonas-like bands were seen in the MPN DNA but were not detected in the DNA extracted directly from soils. These bands were detected in some samples taken from MPN incubations carried out with medium containing 1,000 microg of NH(4)(+)-N ml(-1), to the exclusion of bands detected in the native DNA. Cell concentrations of ammonia oxidizers determined by MPN counts were between 10- and 100-fold lower than those determined by competitive PCR (cPCR). Although no differences were seen in ammonia oxidizer MPN counts from the different soil treatments, cPCR revealed higher numbers in fertilized soils. The use of a combination of traditional and molecular methods to investigate the activities and compositions of ammonia oxidizers in soil demonstrates differences in fine-scale compositions among treatments that may be associated with changes in population size and function.

Phylogeography of Peromyscus furvus (Rodentia; muridae) based on cytochrome b sequence data

We conducted phylogenetic analyses of cytochrome b sequence data to assess genetic variation within and among the three allopatric segments of the distribution of Peromyscus furvus from the Sierra Madre Oriental in eastern Mexico. We identified 24 unique haplotypes among the 54 individuals examined and genetic distances ranged up to 0.078 substitutions per site. Populations from the central portion of the range formed a monophyletic unit, whereas samples from the southern distributional unit were polyphyletic. Furthermore, the southernmost population sampled may represent a distinct species. This high degree of genetic differentiation among populations, currently recognized as conspecific, mirrors the result of other genetic studies of highland rodents in Mesoamerica. Together these studies indicate that the region, already considered hyperdiverse on the basis of species diversity and endemism, may contain considerably greater diversity than is currently appreciated.

Education purchasers' views of nursing as an all graduate profession

The issue of whether nursing should be an all graduate profession is one of the most important questions currently facing the nursing profession. The literature indicates that there are differing views on this issue but that there is little research on the performance of graduate nurses in practice. Purchasers of education have played an increasingly significant part in nurse education since the advent of Working Paper 10 (WP10) (DOH 1989). Purchasers hold the resources for nurse education and can now decide whether to commission for diploma or degree level student nurses, therefore they will have a major influence on the outcome of this debate. The aim of this paper is to discuss the views of the purchasers of education about this issue. A purposeful sample of 34 key stakeholders involved in commissioning and contracting for education was selected and asked for their views on whether nursing will or should become an all graduate profession. Key areas that were focused upon were the problems that might emerge from an all graduate nursing profession, the advantages of graduate level nurses within the NHS, what graduateness is and what it might mean for nursing. The results indicated that purchasers were convinced of the importance of nursing graduates but only as part of the workforce. Alternative ways of increasing the percentage of graduates rather than in pre-registration education were preferred with pathways of education linked to continuing professional development. Significantly, the participants were able to articulate the attributes of a degree level education for clinical practice including leadership, assertiveness, and reflective, critical skills.

The Australian National Workplace Health Project: design and baseline findings

BACKGROUND

This paper describes the study design, recruitment, measurement, and initial recruitment outcomes of Australia's largest workplace intervention trial, the National Workplace Health Project.

METHODS

This was a cluster-randomized trial of socio-behavioral and environmental interventions focusing on key behaviors of physical activity, healthy food choices, cigarette smoking, and alcohol consumption, as well as motivational readiness for change. Twenty worksites were randomized separately for each intervention using a two-by-two factorial design. All participants underwent a health risk appraisal and measurements were made at baseline and at 1 and 2 years.

RESULTS

The overall response rate for the baseline survey was 73% with 61% attending the health risk appraisal. The sample was predominantly male, English-speaking, married, blue-collar workers. Overall, 12% reported unsafe alcohol consumption, 26% were current smokers, 44% were physically inactive, 74% ate at most one piece of fruit per day, and 26% ate at most one serving of vegetables per day. Intervention and control conditions were similar at baseline for the primary outcomes, except that a higher proportion of the sociobehavioral intervention condition was more physically active (59%) than the corresponding control condition (53%).

CONCLUSIONS

This study will permit the rigorous evaluation of the efficacy of sociobehavioral and environ mental intervention approaches to workplace health promotion. Although participants were randomized by worksite, intervention and control conditions were similar at baseline; any differences in the primary out come variables will be controlled for in the analysis.

Role of gap junctions in endothelium-derived hyperpolarizing factor responses and mechanisms of K(+)-relaxation

We have examined the effects of ouabain (1 mM), the gap junction inhibitors, 18 alpha-glycyrrhetinic acid (100 microM), N-(piperidin-1-yl)-5-(4-chlorophenyl)-1-(2, 4-dichlorophenyl)-4-methyl-1H-pyrazole-3-carboxamide hydrochloride (SR141716A; 10 microM) and palmitoleic acid (50 microM), and clotrimazole (10 microM) against endothelium-derived hyperpolarizing factor (EDHF)-mediated and K(+)-induced vasorelaxations in the rat mesentery. In the presence of indomethacin (10 microM) and 300-microM N(G)nitro-L-arginine methyl ester (L-NAME), carbachol caused EDHF-mediated relaxations (R(max)=85.3+/-4.0%). In the presence of ouabain, these responses were substantially reduced (R(max)=11.0+/-2.3%). 18 alpha-glycyrrhetinic acid, SR141716A, palmitoleic acid and clotrimazole also significantly inhibited these EDHF-mediated responses. K(+) caused vasorelaxation of preparations perfused with K(+)-free buffer (R(max)=73.7+/-2.4%), which were reduced by 10-microM indomethacin (R(max)=56.4+/-6.2%). K(+) vasorelaxation was essentially abolished by endothelial denudation. Both ouabain and 18 alpha-glycyrrhetinic acid opposed K(+) relaxations, however, neither SR141716A, clotrimazole nor palmitoleic acid had any effect. Direct cell-cell coupling via gap junctions was attenuated by ouabain, clotrimazole and palmitoleic acid. We conclude that: (i) that gap junctional communication plays a major role in EDHF-mediated relaxations, (ii) that K(+)-vasorelaxation is endothelium-dependent (thus, K(+) is unlikely to represent an EDHF), and (iii) that the inhibitory actions of ouabain and clotrimazole on gap junctions might contribute towards their effects against EDHF.

Liposomal Bcl-2 antisense oligonucleotides enhance proliferation, sensitize acute myeloid leukemia to cytosine-arabinoside, and induce apoptosis independent of other antiapoptotic proteins

The antiapoptotic proteins, Bcl-2 and Bcl-X(L), are expressed in most cases of acute myeloid leukemia (AML) and may contribute to drug resistance in AML. We tested the hypothesis that down-regulation of Bcl-2 alone by antisense oligodeoxynucleotides (Bcl-2-AS) induces apoptosis, even in the presence of other antiapoptotic genes. We tested Bcl-2-AS in myeloid leukemic HL-60 cells, in Bcl-2 and Bcl-X(L) overexpressing HL-60-DOX cells, and in primary AML samples. Down-regulation of Bcl-2 by Bcl-2-AS reduced the viability of HL-60 cells and, less effectively, HL-60-DOX cells and increased ara-C cytotoxicity in both cell lines. Incubation of primary AML blasts with Bcl-2-AS decreased Bcl-2 expression in CD34(+) blast cells after induction of apoptosis and enhancement of ara-C cytotoxicity in 11 of 19 primary AML samples. In 8 samples in which Bcl-2-AS did not induce apoptosis, baseline Bcl-2 levels were found to be strikingly high. The expression of other antiapoptotic proteins (Bcl-X(L), Bag-1, A1, and Mcl-1) did not prevent Bcl-2-AS-induced apoptosis. Bcl-2-AS also inhibited colony formation of AML progenitor cells. Low concentrations of Bcl-2-AS induced significant increases in S-phase cells (P =.04). Results establish Bcl-2 as a critical target for AS strategies in AML in which the baseline levels predict response to Bcl-2-AS. Bcl-2 exerts both antiapoptotic and antiproliferative functions in AML. Because early normal hematopoietic stem cells do not express Bcl-2, Bcl-2-AS therapy should be highly selective for AML cells. (Blood. 2000;95:3929-3938)

"No fear" curricular change: monitoring curricular change in the W. K. Kellogg Foundation's National Initiative on Community Partnerships and Health Professions Education

PURPOSE

To assess the effect of the W. K. Kellogg Foundation's five-year (9/91 to 9/96) primary care curricular change initiative involving seven sites and 27 schools with respect to courses offered, graduates' specialty choices, and valued school features (e.g., reputation, research, productivity, school climate) and to track how well the schools possessed or developed the processes associated with enduring curricular change.

METHOD

Information was collected via pre- and post-surveys of faculty and students, site visits, annual reports, and medical students' specialty match results.

RESULTS

In general, the schools either possessed or developed the institutional, curricular design, and curriculum features associated with successful curricular change. Further, the initiative had a positive or neutral impact on most of the valued features: 199 courses were revised or developed, including 138 offered in the community, involving 141 interdisciplinary faculty. Comparing 1991-1997 data, the average percentage increases in students' selecting primary care from the involved schools were greater than the national percentages. In 1997, a larger percentage of project school graduates selected primary care than the national average.

CONCLUSION

Medical schools can make major curricular changes and achieve intended outcomes (e.g., new and/ or revised courses, multidisciplinary instruction, instruction in the community, and changes in specialty choice), and this can occur without negatively impacting other valued school aspects.

From sequence to chromosome: the tip of the X chromosome of D. melanogaster

One of the rewards of having a Drosophila melanogaster whole-genome sequence will be the potential to understand the molecular bases for structural features of chromosomes that have been a long-standing puzzle. Analysis of 2.6 megabases of sequence from the tip of the X chromosome of Drosophila identifies 273 genes. Cloned DNAs from the characteristic bulbous structure at the tip of the X chromosome in the region of the broad complex display an unusual pattern of in situ hybridization. Sequence analysis revealed that this region comprises 154 kilobases of DNA flanked by 1.2-kilobases of inverted repeats, each composed of a 350-base pair satellite related element. Thus, some aspects of chromosome structure appear to be revealed directly within the DNA sequence itself.

Role of glutamine 151 of human immunodeficiency virus type-1 reverse transcriptase in substrate selection as assessed by site-directed mutagenesis

A natural mutation at codon 151 (Gln --> Met; Q151M) of HIV-1 RT has been shown to confer resistance to the virus against dideoxy nucleoside analogues [Shirasaka, T., et al. (1995) Proc. Natl. Acad. Sci. U.S.A. 92, 2398], suggesting that Gln 151 may be involved in conferring sensitivity to nucleoside analogues. To understand its functional implication, we generated two mutant derivatives of this residue (Q151M and Q151N) and examined their sensitivities to ddNTPs and their ability to discriminate against rNTPs versus dNTP substrates on natural U5-PBS HIV-1 RNA template. We found that Q151M was highly discriminatory against all four ddNTPs but was able to incorporate rNTPs as efficiently as the wild type enzyme. In contrast, the Q151N mutant was only moderately resistant to ddNTPs but exhibited a higher level of discrimination against rNTPs. The fidelity of misinsertion was found to be highest for the Q151N mutant followed by Q151M and the wild type enzyme. These results point toward the importance of the amino acid side chain at position 151 in influencing the ability of the enzyme in recognition and discrimination against the sugar moieties of nucleotide substrates.

Heat-inducible vectors for use in gene therapy

The objectives of this study were to quantity and compare the activities of a minimal heat shock (HS) promoter and other promoters used in gene therapy applications, and to identify strategies to amplify the heat inducibility of therapeutic genes. Human tumour cells were transiently or stably transfected with the HS promoter driving expression of reporter genes. HS promoter activity was induced transiently, with maximum activity 16-24 h after HS, and was dependent on temperature. The activity of the minimal HS promoter was similar, after 42 degrees C HS for 1 h, to that of the cytomegalovirus (CMV) promoter. To determine if the HS promoter could be used to activate a second conditional promoter, cells were transiently transfected with vectors containing both the HS and human immunodeficiency virus type 1 (HIV1) promoters. When the IL-2 gene was placed downstream of the HIV1 promoter. IL-2 production was temperature-independent. The addition of the HIV tat gene downstream of the HS promoter caused IL-2 to be induced more than 3 fold after a single 42 degrees C HS. These data indicate that the minimal HS promoter, following activation by clinically attainable temperatures (< or = 42 degrees C), can drive expression of therapeutic genes at levels comparable to the CMV promoter and be used in conjunction with a second conditional promoter to drive temperature-dependent, gene expression.