STUDIES ON THE CULTIVATION OF THE VIRUS OF LYMPHOGRANULOMA VENEREUM

Two strains of the lymphogranuloma venereum virus were maintained in tissue cultures for 12 and 21 generations respectively. In a third strain a quantitative increase in potency as high as 1000 times was obtained by inoculating tissue cultures with infected emulsions of known virulence. Greater increases in potency were consistently obtained by maintaining tissue cultures and virus at room temperature (23°C. with a range of approximately ± 5°C.) than by incubating them at 37°C. The virus did not survive in the absence of oxygen. Embryonic guinea pig brain and serum ultrafiltrate were found to be the most effective vehicles for propagation of the lymphogranuloma virus. There is evidence that the site of activity for this virus is intracellular. Embryonic guinea pig brain cells were maintained in the serum ultrafiltrate diluted with buffered salt solution in good (morphologic) condition for as long as 70 days. Not only could old cultures be successfully inoculated with the virus of lymphogranuloma, but high titres could be maintained over extended periods.

STUDIES IN RODENT POLIOMYELITIS : III. EXPERIMENTAL POLIOMYELITIS IN GUINEA PIGS PRODUCED WITH THE MURINE STRAIN OF SK POLIOMYELITIS VIRUS

1. Murine SK poliomyelitis virus has been transferred from mouse to guinea pig with the establishment of a fixed strain of cavian passage virus. 2. The disease thus produced in guinea pigs is characterized by the occurrence of flaccid paralysis. Typical poliomyelitic lesions are found in the anterior horn of the spinal cord. 3. Guinea pigs are susceptible to infection with murine virus by the intracerebral, intravenous, intraperitoneal, and subcutaneous route; cavian passage virus produces paralysis only upon intracerebral or intravenous injection. Neither virus paralyzes guinea pigs by feeding or nasal instillation. 4. The potency of the virus (murine or cavian) in guinea pigs is considerably lower than in mice and compares with the titer of the original SK strain in monkeys. In paralyzed guinea pigs the virus is found only in the central nervous system and not in extraneural sites, such as blood or abdominal viscera. 5. Attempts to cultivate cavian passage virus in tissue culture have yielded evidence of some in vitro propagation but no passage virus has as yet been obtained by this method. 6. Cross neutralization tests with cavian passage virus in guinea pigs and with murine virus in mice have established the serological identity of the two viruses. Inactivation of cavian passage virus in guinea pigs by poliomyelitis-convalescent monkey sera is irregular. Complete neutralization has been obtained with a concentrated poliomyelitis horse serum. 7. Resistance to reinfection with potent virus can be demonstrated in convalescent guinea pigs as well as in guinea pigs which have survived a symptomless infection with either murine or cavian virus. This immunity is demonstrable by the power of the serum of such animals to neutralize the virus in vitro and by the ability of nerve tissue to dispose in vivo of the infectious agent. 8. Cavian passage virus has a limited pathogenicity for rhesus monkeys. Of a total of 35 monkeys injected intracerebrally with guinea pig passage virus 26 failed to respond with any manifest symptoms of disease; 8 monkeys showed various signs of definite involvement of the central nervous system consisting of tremor, convulsions, facial palsy, and localized pareses; 1 monkey developed typical flaccid paralysis. 9. Following injection with cavian virus the virus may be recovered from the tissues of normal monkeys but not from the tissues of convalescent monkeys shortly after a paralyzing attack of poliomyelitis due to SK or Aycock virus. 10. Immunization of monkeys with early cavian passage virus by the subcutaneous route has given no clear-cut evidence of protection against intracerebral reinfection with SK poliomyelitis virus. Neither has there been any evidence of effective interference in monkeys injected intravenously with early cavian passage virus and intracerebrally with RMV poliomyelitis virus. 11. The bearing of the experimental data upon the epidemiology of the human disease is discussed.

EPIDEMIC KERATOCONJUNCTIVITIS : I. ISOLATION AND IDENTIFICATION OF A FILTERABLE VIRUS

1. A virus has been isolated from two patients suffering with epidemic keratoconjunctivitis. 2. At first the virus could be maintained only by the inoculation of tissue cultures (serum ultrafiltrate and embryonic mouse brain) with conjunctival scrapings or with emulsified mouse brains from early passage animals. Later it caused a fatal disease in every mouse into which it was inoculated, and could, then be readily maintained in mice. 3. The virus proved pathogenic for unweaned white Swiss mice by the intranasal, intraperitoneal, and intracerebral routes; for adult mice by the intranasal and intracerebral routes, and for rabbits by only the intracerebral route. 4. Although the titer of tissue cultures rarely exceeded 10^–2 or 10^–3, the virus, once established in mice, increased in potency until titers of 10^–5 and 10^–6 were attained. Mice injected with either the emulsion of mouse brain tissue or with the tissue culture material in these dilutions developed symptoms within a definite incubation period; once the disease was initiated, it followed a characteristic course for a period of a few to 24 hours, and consistently terminated in death. 5. The pathological changes in mice were limited to the central nervous system, and were not particularly distinctive. The neurotropic character of the virus is further shown by the fact that only the brain tissue was consistently pathogenic for mice. 6. Serial tissue cultures could be maintained only at room temperature, and when the inoculum from virus-infected cultures into fresh tissue cultures contained ground-up cells. 7. The highest level of potency in cultures occurred on about the 6th day at room temperature. 8. The virus passed without difficulty through an E-K Seitz filter (double pads) and through all grades of Berkefeld filters. 9. The virus passed consistently through graded collodion membranes with an A.P.D. of 75 to 100 millimicrons and to a lesser extent through those with an A.P.D. of 50 to 75 millimicrons. Membranes with an A.P.D. of less than 50 millimicrons retained the virus. 10. The mouse virus was not neutralized by anti-lymphocytic choriomeningitis serum, antiherpes serum, normal human serum, or serum from cases of non-specific conjunctivitis or keratitis. 11. Mice hyperimmunized to Theiler's virus were susceptible to the mouse keratoconjunctivitis virus. The latter virus was also not neutralized by hyperimmune Theiler rabbit serum. 12. The mouse virus could be neutralized by serum from the two patients from whom the virus had been isolated, and also by that from the three patients convalescing from epidemic keratoconjunctivitis in California and the serum of a convalescent in New York. The neutralization data were confirmed by tests on 15 additional convalescent serums (unpublished data). 13. A mild but characteristic picture of epidemic keratoconjunctivitis was reproduced in a human volunteer following inoculation with the mouse virus. 14. The serum of the human volunteer, while not neutralizing the mouse virus before infection, contained neutralizing antibodies 1 month after infection. 15. Development of antibodies was demonstrated in one patient (R.H.) in the present series, and in six other patients of another series (unpublished data).

STUDIES IN RODENT POLIOMYELITIS : V. INTERFERENCE BETWEEN MURINE AND MONKEY POLIOMYELITIS VIRUS

1. The murine strain of SK poliomyelitis virus interferes with the propagation in rhesus monkeys of SK, Aycock, and RMV poliomyelitis monkey virus. 2. This interference is demonstrable by intracerebral injection of mixtures of murine and monkey virus prepared in vitro as well as by separate injection of the two viruses by diverse routes. 3. Mixture tests carried out with graded doses of murine and monkey virus show that 0.5 cc. of a 10 per cent suspension prepared from the brains of paralyzed mice is capable of counteracting at least 100 minimal paralyzing doses of two strains of monkey virus. 4. No interference was demonstrable with suspensions of brains infected with murine virus which had been inactivated by heating for (1/2) hour at 75 degrees C., or with suspensions prepared from normal mice, or with brain suspensions prepared from mice infected with herpes virus. 5. When murine virus is introduced into monkeys by the intravenous route, before or after intracerebral infection with monkey virus, distinct prophylactic or therapeutic results may be obtained. 6. Analysis of the figures shows that the success of interference depends upon (a) the size of the infecting dose of monkey virus, (b) the amount of murine virus injected, and (c) the choice of proper intervals between the injection of monkey and murine virus. 7. The mechanism of the interference phenomenon here described is discussed in the light of the available data.

Proteomic Discrimination of Well- from Poorly-Differentiated Breast Carcinomas

Background: Pathological grade is a useful prognostic factor for stratifying breast cancer patients into favorable (well-differentiated tumors) and less favorable (poorly-differentiated tumors) outcome groups. The current system of tumor grading, however, is highly subjective and a large proportion of tumors are characterized as intermediate-grade, making determination of optimal treatments difficult.Methods: Primary breast tumor specimens from patients diagnosed with well- (n=27) and poorly-differentiated (n=51) invasive ductal carcinoma were obtained from patients enrolled in the Clinical Breast Care Project. Frozen tissues were sectioned and mounted on gold coated MALDI target plates for protein expression profiling. Hematoxylin and eosin (H&E) stained slides were prepared from serial sections for histological characterization. MALDI matrix was deposited as individual spots on the tissue sections in a histology directed manner to assay specific areas and tissue types of interest. Mass spectral data were then acquired from multiple sites across each tissue section.Results: 129 features were observed in well-differentiated and 132 in poorly-differentiated tumors. While the majority of features detected were similar between the two groups, 6 protein features were expressed at significantly lower and 12 at significantly higher levels in the poorly-differentiated tumors, including increased expression of Calgranulin A and Calgizzarin.Conclusions: Protein expression differences detected here suggest that well- and poorly-differentiated invasive breast tumors are molecularly distinct diseases and that these protein changes may contribute to the structural integrity of the tumor cell. In particular, calgranulin A and calgizzarin are members of the S100 protein family, and function in processes such as cell proliferation and differentiation. Further refinement of this differentiation protein signature may not only improve our understanding of the biological processes involved with tumor grade but provide pathologists with new molecular tools to classify breast tumors and reduce the subjectivity associated with current grading criteria.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 6126.

The genome of the simian and human malaria parasite Plasmodium knowlesi

Plasmodium knowlesi is an intracellular malaria parasite whose natural vertebrate host is Macaca fascicularis (the 'kra' monkey); however, it is now increasingly recognized as a significant cause of human malaria, particularly in southeast Asia. Plasmodium knowlesi was the first malaria parasite species in which antigenic variation was demonstrated, and it has a close phylogenetic relationship to Plasmodium vivax, the second most important species of human malaria parasite (reviewed in ref. 4). Despite their relatedness, there are important phenotypic differences between them, such as host blood cell preference, absence of a dormant liver stage or 'hypnozoite' in P. knowlesi, and length of the asexual cycle (reviewed in ref. 4). Here we present an analysis of the P. knowlesi (H strain, Pk1(A+) clone) nuclear genome sequence. This is the first monkey malaria parasite genome to be described, and it provides an opportunity for comparison with the recently completed P. vivax genome and other sequenced Plasmodium genomes. In contrast to other Plasmodium genomes, putative variant antigen families are dispersed throughout the genome and are associated with intrachromosomal telomere repeats. One of these families, the KIRs, contains sequences that collectively match over one-half of the host CD99 extracellular domain, which may represent an unusual form of molecular mimicry.

Identification of proteins promoting development of metastatic breast tumors

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Background: Primary breast tumors are constantly shedding tumor cells into the circulatory and lymphatic systems. Although detection of occult tumor cells is a risk factor for recurrence and progression, tumor cells remain detectable years after initial diagnosis in patients without clinical or histological detection of metastasis. Thus the question remains as to why some women with circulating tumor cells develop metastatic breast cancer while others do not. Methods: Negative lymph nodes from women with node negative (n=22) and node positive disease (n=36) were obtained from patients enrolled in the Clinical Breast Care Project. Negative lymph node status was confirmed by IHC analysis. Frozen tissues were sectioned and mounted on gold coated MALDI target plates for protein expression profiling. Hematoxylin and eosin (H&E) stained slides were prepared from serial sections for histological characterization. MALDI matrix was deposited as individual spots on the tissue sections in a histology directed manner to assay specific areas and tissue types of interest. Mass spectral data were then acquired from multiple sites across each tissue section. Results: 131 features were observed in negative nodes from patients without metastatic disease and 129 in negative nodes from patients with lymph node metastases. While the majority of features detected were similar between the two groups, 8.5% were differentially expressed. Two of the features which were expressed at significantly higher levels in nodes from patients with metastatic disease have been putatively identified as thymosin β4 and thymosin β10. Conclusions: Thymosin β4 and 10 have been associated with disease progression and metastatic capacity in a number of tumor types. The overexpression of these proteins in tumor-negative nodes from patients with metastatic disease in other regional nodes suggests lymph nodes do not play a passive role in metastasis, rather, expression of a specific subset of proteins creates an hospitable environment to facilitate colonization. These markers of metastasis may permit molecular discrimination of those patients with indolent disease from those at risk for metastasis and will thus allow for the design of customized treatment regimens to more effectively treat, or prevent, metastatic spread.

No significant financial relationships to disclose.

Overexpression of chemokine receptor CXCR4 in cancer specimens following neoadjuvant chemotherapy predicts outcome in patients with locally advanced breast cancer (LABC)

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Background: Despite significant advances made in the treatment of locally advanced breast cancer (LABC) with neoadjuvant chemotherapy, a significant number of patients continue to die. A molecular predictor to identify those who are at an increased risk for relapse is sorely needed. CXCR4 is a chemokine receptor that has been linked to breast cancer invasion and metastasis. We postulate that CXCR4 overexpression levels in cancer specimens following neoadjuvant chemotherapy predict cancer outcome in patients with LABC. Methods: 54 patients with LABC were prospectively accrued and analyzed. All had neoadjuvant chemotherapy, followed by definitive surgical and adjuvant chemo-radiation therapy. Study homogeneity was maintained by standardized treatment, surveillance, and compliance protocols. A 1 cm 3 cancer from the surgical specimens of each patient was retrieved for analysis. CXCR4 levels were detected using Western blots and results were quantified against 1 μg of HeLa cells (positive controls). CXCR4 expression was defined as low (<6.6 fold) or high (= 6.6 fold). Primary endpoints were cancer recurrence and death. Statistical analysis performed included Kaplan-Meier survival analysis, log-rank test, and Cox proportional hazard model. Results: With a median follow-up of 30 months, patients whose tumors had high CXCR4 overexpression (= 6.6 fold) had a statistically significantly higher incidence of recurrence (p= 0.0009) and cancer-related death (p= 0.0168) than those in the low CXCR4 group (< 6.6 fold). After adjusting for tumor size, nodal status, ER, PR and HER-2 status, the relative risk for recurrence and death in the high CXCR4 group was 27.3-fold (p=0.001; 95% CI: 6.2 to 120.8) and 4.8-fold (p=0.0076; 95% CI: 1.5 to 15.0) higher than those in the low CXCR4 group, respectively. Conclusion: High CXCR4 overexpression in cancer specimens following neoadjuvant chemotherapy was highly predictive of cancer recurrence and cancer death in patients with LABC.

No significant financial relationships to disclose.

Rifampicin mono-resistant Mycobacterium tuberculosis in Bujumbura, Burundi: results of a drug resistance survey

SETTING

Bujumbura, Burundi.

OBJECTIVES

To determine resistance levels of Mycobacterium tuberculosis (TB) to the main anti-tuberculosis drugs after 11 years of a DOTS programme using a WHO-recommended partially intermittent 6-month rifampicin (RMP) first-line regimen and fixed-dose drug combinations (FDCs).

DESIGN

Drug susceptibility testing of systematic samples of M. tuberculosis isolated from newly registered sputum smear-positive cases in the capital during a 15-month period (2002-2003).

RESULTS

Of 496 strains from new cases, 16.1% showed resistance to any drug, 6.3% to isoniazid (INH), 2.0% to RMP (1.4% multidrug-resistant TB [MDR-TB]), 13.3% to streptomycin and 1.6% to ethambutol. Among 69 strains from previously treated cases, the prevalence of resistance was 30%, 19%, 15% (12% MDR-TB strains), 25% and 6%, respectively.

CONCLUSION

Levels of drug resistance in Bujumbura are higher than average for Africa, despite long-term use of the DOTS strategy with FDCs and a ban on sales of TB drugs. Most worrying is the appearance of MDR-TB and RMP-resistant, INH-susceptible strains in new cases. Although a survey cannot prove that high HIV prevalence, elevated levels of resistance to some other drugs and irregular intake allowed acquisition of drug resistance, the effectiveness and safety of 6-month regimens with (partially) intermittent RMP throughout under such conditions should be investigated.

Regional implementation of the NWC guideline on ST-elevation myocardial infarction: Report from the Task Force Prehospital Triage Zuidoost Brabant (PHT ZoB)

BACKGROUND

The NVVC guideline on ST-elevation myocardial infarction forms the basis for the regional prehospital triage (PHT) project in Zuidoost Brabant. In this project diagnosis and treatment strategies are determined in the ambulance.

AIM

To summarise quality assessment and clinical results after one year.

METHODS

We evaluated the protocol and patient record form, the patient's call, assignment of tasks, diagnosis, treatment, time intervals, information to hospitals, cooperation and data transmission. Time delays were compared with time delays in a regional dry run before the start of the project and with time delays reported in the literature.

RESULTS

Patients still wait over one hour before seeking medical attention. The GP received the majority (65%) of patient calls. In half of all cases (51%), GPs call the ambulance centre only after they have seen the patient. When the patient calls the ambulance centre (35%), information to the GP is either prompt or absent. In 77% of calls to 112 it remains unclear whether the GP was informed at all. The treatment strategy was correct in 97% of cases. Time between symptoms and call decreased in comparison with our local preliminary investigation. Quality assessment after one year shows protocol deviations that are either logical procedural improvements or correctable flaws with no substantial negative influence.

CONCLUSION

Short-term clinical results are good, but structured follow-up is needed to reduce mortality in the long term, especially after thrombolysis. A guideline is a snapshot of a dynamic process. The PHT project allows rapid adaptations to be made to new paradigms.

Otolithenfunktionstests - Ein differenziertes, qualitätsgesichertes Screeningsystem

INTRODUCTION

More than 30% of all otogenic vestibular disorders are related to isolated macular dysfunction. Videooculographic examination techniques for the otolith-ocular reflex, e. g. by means of eccentric rotation tests, are not widely used in clinical routine as these put a considerable strain on technical and staff resources. Thus, there is a considerable risk of "false negative" classification of vertigo disorders being labelled as "non-otogenic". By means of vestibular-evoked myogenic potentials (VEMPs) and caloric irrigation in prone and supine position, several examination techniques for a side-related investigation of macula-induced vestibulo-ocular reflexes are available. The objective of this study is to compare and evaluate these techniques as screening tests.

METHODS

In 32 patients with vestibular disorders we performed investigations for VEMPs, eccentric rotation tests, as well as caloric irrigation for macular reaction in prone and supine position. In addition, we performed other audiologic and vestibular function tests which were complemented by the clinical course in order to differentiate each case between otogenic and non-otogenic vertigo with or without macular affection.

RESULTS

The technical feasibility as well as patients' acceptance for VEMP testing is better than for eccentric rotation tests. The sensitivity index for VEMPs (89%) as well as for caloric irrigation in prone and supine position for macular examination (71%) is satisfactory. However, the specificity of VEMPs is inferior (53%) to eccentric rotation (100%).

DISCUSSION

Both the examination for VEMPs as well as caloric macular testing in prone and supine position carry features which make them feasible for screening, even though these two procedures test for two different parts of the otolith system. However, to confirm a diagnosis and to set up a therapeutic concept for macular function disorders, eccentric rotation should be added.

The genome of the social amoeba Dictyostelium discoideum

The social amoebae are exceptional in their ability to alternate between unicellular and multicellular forms. Here we describe the genome of the best-studied member of this group, Dictyostelium discoideum. The gene-dense chromosomes of this organism encode approximately 12,500 predicted proteins, a high proportion of which have long, repetitive amino acid tracts. There are many genes for polyketide synthases and ABC transporters, suggesting an extensive secondary metabolism for producing and exporting small molecules. The genome is rich in complex repeats, one class of which is clustered and may serve as centromeres. Partial copies of the extrachromosomal ribosomal DNA (rDNA) element are found at the ends of each chromosome, suggesting a novel telomere structure and the use of a common mechanism to maintain both the rDNA and chromosomal termini. A proteome-based phylogeny shows that the amoebozoa diverged from the animal-fungal lineage after the plant-animal split, but Dictyostelium seems to have retained more of the diversity of the ancestral genome than have plants, animals or fungi.

Intracellular free radical production in synovial T lymphocytes from patients with rheumatoid arthritis

OBJECTIVE

To investigate the cellular and molecular sources of oxidative stress in patients with rheumatoid arthritis (RA) through analysis of the production of reactive oxygen species (ROS) in synovium.

METHODS

Cytochemical procedures based on the 3,3'-diaminobenzidine (DAB)-Mn2+ deposition technique were used on unfixed cryostat sections of synovium from RA patients and rheumatic disease controls. For immunophenotyping, sections were incubated, fixed, and stained with fluorescein isothiocyanate-labeled antibodies. Fluorescence-activated cell sorter analysis of the ROS-reactive dye 6-carboxy-2',7'-dichlorodihydrofluorescein diacetate-di(acetoxymethyl ester) was used to measure intracellular ROS in T lymphocytes from peripheral blood and synovial fluid. To determine which enzymes produced ROS, different inhibitors were tested.

RESULTS

Large quantities of DAB precipitated in the majority of RA synovial T lymphocytes, indicative of intracellular ROS production. These ROS-producing T lymphocytes were observed throughout the synovium. Polymerization of DAB was observed to a lesser extent in other forms of chronic arthritis, but was absent in osteoarthritis. DAB staining of cytospin preparations of purified RA synovial fluid T cells confirmed the presence of ROS-producing cells. One of the ROS involved appeared to be H2O2, since catalase suppressed intracellular ROS production. Superoxide dismutase, which uses superoxide as a substrate to form H2O2, diphenyleneiodonium (an inhibitor of NADPH oxidase), N(G)-monomethyl-L-arginine (an inhibitor of nitric oxide synthesis), nordihydroguaiaretic acid (an inhibitor of lipoxygenase), and rotenone (an inhibitor of mitochondrial ROS production) failed to suppress ROS production.

CONCLUSION

Our findings show that chronic oxidative stress observed in synovial T lymphocytes is not secondary to exposure to environmental free radicals, but originates from intracellularly produced ROS. Additionally, our data suggest that one of the intracellularly generated ROS is H2O2, although the oxidase(s) involved in its generation remains to be determined.

Comparison of anatomical tibial plateau angle versus observer measurement from lateral radiographs in dogs

This study was conducted to compare the anatomical tibial plateau angle (TPA) with that measured by observers from a lateral radiograph of the limb, the hypothesis being that there would not be any statistically significant differences between the observer measured TPA and the true anatomical TPA. Twelve pelvic limbs from skeletally mature greyhound cadavers, without any clinical or radiographic evidence of stifle pathology, were used in this study. The radiographs were taken of each limb in a lateral position with the primary beam centered over the tibial eminences and collimated to include the stifle and tarso-crural joints. For subsequent radiographs, Kirschner wires were inserted to enable identification of the tibial plateau. The TPA was then measured, by three observers, from the plain radiographs and by one observer from the marked radiographs. The mean observer TPA was 24.4 degrees (range 17-30 degrees) and the mean anatomical TPA was 23.8 degrees (range 15-31 degrees). The mean and median discrepancy between the anatomical TPA and the observer TPA was negative and very small (- 0.64 degrees and 0 degrees). The magnitude of the discrepancy between individual measurements made by the observers tended to overestimate small angles and underestimate the large ones, and this trend is statistically significant. These results suggest that the measurements made by observers accurately represent the anatomical slope of the tibial plateau. Therefore, observer TPA is suitable for the planning and assessment of TPLO procedures. However, as the anatomical TPA moves away from a median angle (23.25 degrees) the magnitude of error in the measurement increases.

Genome sequence of the enterobacterial phytopathogen Erwinia carotovora subsp. atroseptica and characterization of virulence factors

The bacterial family Enterobacteriaceae is notable for its well studied human pathogens, including Salmonella, Yersinia, Shigella, and Escherichia spp. However, it also contains several plant pathogens. We report the genome sequence of a plant pathogenic enterobacterium, Erwinia carotovora subsp. atroseptica (Eca) strain SCRI1043, the causative agent of soft rot and blackleg potato diseases. Approximately 33% of Eca genes are not shared with sequenced enterobacterial human pathogens, including some predicted to facilitate unexpected metabolic traits, such as nitrogen fixation and opine catabolism. This proportion of genes also contains an overrepresentation of pathogenicity determinants, including possible horizontally acquired gene clusters for putative type IV secretion and polyketide phytotoxin synthesis. To investigate whether these gene clusters play a role in the disease process, an arrayed set of insertional mutants was generated, and mutations were identified. Plant bioassays showed that these mutants were significantly reduced in virulence, demonstrating both the presence of novel pathogenicity determinants in Eca, and the impact of functional genomics in expanding our understanding of phytopathogenicity in the Enterobacteriaceae.

Systematic restaining of sputum smears for quality control is useful in Burundi

SETTING

Routine tuberculosis control services in Burundi.

OBJECTIVE

To determine whether systematic restaining of sputum smears for acid-fast bacilli (AFB) prior to rechecking quality assessment is necessary.

DESIGN

Blinded rechecking of peripheral routine smears, including a second control of discordants, before and after restaining.

RESULTS

Without restaining, 10/825 (1.2%) negative, and 59/189 (31.2%) positive results were declared false. After restaining, there were 34 (4.1%) false negatives and 13 (6.9%) false positives, both highly significant changes. Before restaining, quantification of positive smears was usually considered too high, while after restaining 41 out of 42 positives were found to have too low readings.

CONCLUSIONS

Despite mild climatic conditions in Burundi, restaining all slides before rechecking revealed an unrecognised, widespread problem of false negatives, rather than false positives. This indicated the need for critical re-appraisal of the standard procedure using cold staining, rather than re-training, as would have been inferred from results without restaining. Systematic restaining of all slides prior to rechecking may be more widely needed in National Tuberculosis Programmes to cover all possible serious causes of error. Cold staining should be avoided in field programmes since its performance is easily affected by frequently encountered adverse factors.

Origin and distribution of polycyclic aromatic hydrocarbons in surficial sediments from the savannah river

Surface sediments collected from the Savannah River, located in the southeastern state of Georgia, USA, in June-July 1994 were analyzed for individual polycyclic aromatic hydrocarbons (PAHs). Three subdivisions of the river were identified for the study: upstream from, adjacent to, and downstream from the city of Savannah. There was high spatial variability in the total PAH (SigmaPAH) concentrations that ranged from 29 to 5,375 ng/g with an average concentration of 1,216 +/- 1,161 (SD). Of the three subdivisions, the highest SigmaPAH concentrations were in the middle segment, which was adjacent to urban and industrial areas. To elucidate sources, molecular indices based on indices among phenanthrene versus anthracene and fluoranthene versus pyrene were used to determine pyrogenic and petrogenic sources, respectively. These indices have been used by other authors to differentiate sources. In most cases, PAHs in sediments nearest the city of Savannah were of high temperature and pyrogenic origin. These pyrogenic PAHs were highly associated with toxicity to benthic organisms. The two-ringed naphthalene and substituted naphthalenes, which are petroleum-related PAHs, were significantly higher in the lower section of the river relative to the subdivisions. This river segment receives inputs primarily from shipping and boating traffic. Perylene, which is indicative of nonanthropogenic terrestrial inputs of carbon, had the highest concentration among the individual PAHs measured. High perylene concentrations were found at stations located upstream and adjacent to forested terrain and where salinity level was low. To discriminate pattern differences and similarities of individual PAHs among samples, principal component analysis (PCA) was performed on the more hydrophobic and persistent nonalkylated PAHs. These differences and similarities were used to infer perylene origin. PCA was performed on 14 nonalkylated PAHs that was normalized to the sum of nonalkylated PAHs, using a correlation matrix. Generally, the PAHs were separated into group patterns according to chemical and physical properties associated with log K(OW), except perylene. Perylene, a five-ringed PAH, was distinctly separated from the other five-ringed PAHs. The sources for perylene are likely from biogenic, terrestrial precursors. The collected data show that pyrogenic PAHs were highly associated with biological effects on benthic organisms, based on bioassay results. Perylene, a nonanthropogenic PAH, was found throughout the river and constituted a large percentage of total PAHs in the upper river.

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.

Toxicological studies in tropical ecosystems: an ecotoxicological risk assessment of pesticide runoff in South Florida estuarine ecosystems

A multiyear study in the C-111 canal system and associated sites in Florida Bay was undertaken to determine the potential pesticide risk that exists in South Florida. After the examination of extensive pesticide concentration data in surface water, tissues, and semipermeable membrane devices (SPMDs), canal contamination seems to be derived from the extensive agricultural production that drains into the C-111 canal. The results of this study indicate that runoff from agricultural processes led to quantifiable pesticide residues in both canal and bay surface water, which occasionally exceeded current water quality criteria. The major pesticide of concern was endosulfan, which was detected at 100% of the sites sampled. Endosulfan exposure did not cause any acute effects in fish and crustaceans deployed in field bioassays. Chronic effects were observed in copepods, clams, and oysters but could not be attributed to endosulfan exposure. The decision to alter the C-111 canal flow and allow increased freshwater flow into the adjacent Everglades National Park may result in discharges of pesticides into the Everglades. Continued monitoring in this area is needed during this change in flow regime.