Lead concentrations and labeling of new paint in cameroon.

In spite of the availability of substitutes for lead compounds used in paints, manufacturers continue to produce these paints for decorative and industrial applications. We report here on the concentration of lead in new paint sold in Cameroon and provide a summary of labeling practices on paints available in the country, based on a market survey. Investigators visited 76 retail and wholesale paint suppliers in Cameroon to collect information from paint product labels and to collect samples of paints to analyze for lead content. Only 8.5% of paints had labels identifying any of the ingredients, and none of the lead paints included any warning language. Based on a convenience sample (weighted to include multiple colors from the most common brands), 61 mostly enamel paints were purchased from retail outlets and analyzed for lead content (median: 2150 ppm; range: <21-500,000 ppm). Sixty-six percent of the new paint samples had concentrations exceeding the U.S. standard of 90 ppm total lead. All but one of the samples with lead concentrations greater than 90 ppm were also greater than 600 ppm. The largest manufacturer in the country-Seigneurie, a subsidiary of the U.S.-based company PPG-had significant lead concentrations in 9 out of 22 (41%) paints tested. There is an immediate need to adopt mandatory standards to limit the lead content of paint manufactured, imported, and sold in the country. To promote safer paint products we recommend the development of a third-party certification program for paints without added lead. These recommendations are consistent with the objectives of the Global Alliance to Eliminate Lead Paint established under the auspices of the United Nations to address this problem on a global scale.

Histopathologic evaluation of arterial wall response to 5 neurovascular mechanical thrombectomy devices in a swine model.

BACKGROUND AND PURPOSE: Five commercial devices are available for mechanical thrombectomy in acute ischemic stroke. This study evaluated and compared the resultant arterial damage from these devices. MATERIALS AND METHODS: Wall damage after 4 wall-contact devices (the Merci retriever, Catch thromboembolectomy system, and Solitaire FR revascularization devices of 4 and 6 mm) and 1 aspiration device (the Penumbra System) was evaluated in the superficial femoral arteries of 20 male swine. Each device was tested with and without intraluminal clot. Twenty control vessels were not subjected to any intervention. Acute histopathologic changes were evaluated. RESULTS: In the device samples, endothelial denudation (72.8 ± 29.4% versus 0.9 ± 1.9%, P < .0001), medial layer edema (52 ± 35.9% versus 18.1 ± 27.8%, P = .004), and mural thrombus (5.3 ± 14.2% versus 0%, P = .05) were found to a greater extent compared with the control samples. The aspiration device provoked more intimal layer (100 ± 79.1% versus 58.8 ± 48.9%, P = .27) and medial layer (75 ± 35.4% versus 46.3 ± 34.8%, P = .13) edema than the wall-contact devices. CONCLUSIONS: All devices caused vascular injuries extending into the medial layer. The aspiration device was associated with more intimal and medial layer edema, compared with the wall-contact devices except for the Catch thromboembolectomy system.

A multiplex-PCR assay for identification of the quarantine plant pathogen Xanthomonas axonopodis pv. phaseoli.

In this study we developed an algorithm to screen for all exact molecular signatures of the quarantine pathogen Xanthomonas axonopodis pv. phaseoli (Xap), based on available data of the presence or absence of virulence-associated genes. The simultaneous presence of genes avrBsT and xopL is specific to Xap. Therefore we developed a multiplex PCR assay targeting avrBsT and xopL for the molecular identification of Xap. The specificity of this multiplex was validated by comparison to that of other molecular identification assays aimed at Xap, on a wide collection of reference strains. This multiplex was further validated on a blind collection of Xanthomonas isolates for which pathogenicity was assayed by stem wounding and by dipping leaves into calibrated inocula. This multiplex was combined to the previously described X4c/X4e molecular identification assay for Xap. Such a combination enables the molecular identification of all strains of Xanthomonas pathogenic on bean. Results also show that assay by stem wounding does not give reliable results in the case of Xap, and that pathogenicity assays by dipping should be preferred.

Adhesion and fitness in the bean phyllosphere and transmission to seed of Xanthomonas fuscans subsp. fuscans.

Deciphering the mechanisms enabling plant-pathogenic bacteria to disperse, colonize, and survive on their hosts provides the necessary basis to set up new control methods. We evaluated the role of bacterial attachment and biofilm formation in host colonization processes for Xanthomonas fuscans subsp. fuscans on its host. This bacterium is responsible for the common bacterial blight of bean (Phaseolus vulgaris), a seedborne disease. The five adhesin genes (pilA, fhab, xadA1, xadA2, and yapH) identified in X. fuscans subsp. fuscans CFBP4834-R strain were mutated. All mutants were altered in their abilities to adhere to polypropylene or seed. PilA was involved in adhesion and transmission to seed, and mutation of pilA led to lower pathogenicity on bean. YapH was required for adhesion to seed, leaves, and abiotic surfaces but not for in planta transmission to seed or aggressiveness on leaves. Transmission to seed through floral structures did not require any of the known adhesins. Conversely, all mutants tested, except in yapH, were altered in their vascular transmission to seed. In conclusion, we showed that adhesins are implicated in the various processes leading to host phyllosphere colonization and transmission to seed by plant-pathogenic bacteria.

The Type III secretion system of Xanthomonas fuscans subsp. fuscans is involved in the phyllosphere colonization process and in transmission to seeds of susceptible beans.

Understanding the survival, multiplication, and transmission to seeds of plant pathogenic bacteria is central to study their pathogenesis. We hypothesized that the type III secretion system (T3SS), encoded by hrp genes, could have a role in host colonization by plant pathogenic bacteria. The seed-borne pathogen Xanthomonas fuscans subsp. fuscans causes common bacterial blight of bean (Phaseolus vulgaris). Directed mutagenesis in strain CFBP4834-R of X. fuscans subsp. fuscans and bacterial population density monitoring on bean leaves showed that strains with mutations in the hrp regulatory genes, hrpG and hrpX, were impaired in their phyllospheric growth, as in the null interaction with Escherichia coli C600 and bean. In the compatible interaction, CFBP4834-R reached high phyllospheric population densities and was transmitted to seeds at high frequencies with high densities. Strains with mutations in structural hrp genes maintained the same constant epiphytic population densities (1 x 10(5) CFU g(-1) of fresh weight) as in the incompatible interaction with Xanthomonas campestris pv. campestris ATCC 33913 and the bean. Low frequencies of transmission to seeds and low bacterial concentrations were recorded for CFBP4834-R hrp mutants and for ATCC 33913, whereas E. coli C600 was not transmitted. Moreover, unlike the wild-type strain, strains with mutations in hrp genes were not transmitted to seeds by vascular pathway. Transmission to seeds by floral structures remained possible for both. This study revealed the involvement of the X. fuscans subsp. fuscans T3SS in phyllospheric multiplication and systemic colonization of bean, leading to transmission to seeds. Our findings suggest a major contribution of hrp regulatory genes in host colonization processes.

Do cytokeratin-positive-only sentinel lymph nodes warrant complete axillary lymph node dissection in patients with invasive breast cancer?

The small number of nodes harvested with lymphatic mapping and sentinel lymph node (SLN) biopsy has allowed a more detailed pathologic examination of those nodes. Immunohistochemical stains for cytokeratin (CK-IHC) have been used in an attempt to minimize the false negative rate for SLN mapping. This study examines the value of CK-IHC positivity in predicting further lymph node involvement in the axillary basin. From April 1998 through May 1999, 519 lymphatic mappings and SLN biopsies were performed for invasive breast cancer. SLNs were examined by imprint cytology, hematoxylin and eosin (H&E), and CK-IHC. Patients with evidence of metastatic disease by any of the above techniques were eligible for complete axillary node dissection (CAND). The frequency with which these modalities predicted further lymph node involvement in the axillary basin was compared. Of the 519 lymphatic mappings, 39 patients (7.5%) had a CK-IHC-positive-only SLN. Five (12.8%) of these 39 patients had at least 2 SLNs positive by CK-IHC. Twenty-six of the CK-IHC-positive-only patients underwent CAND. Three of these 26 patients (11.5%) had additional metastases identified after CAND. The sensitivity levels with which each modality detected further axillary lymph node involvement were as follows: CK-IHC, 98 per cent; H&E, 94 per cent; and imprint cytology, 87 per cent. A logistic regression to compare the prognostic value of the three modalities was performed. All were significant, with odds ratios of 19.1 for CK-IHC (P = 0.015), 5.3 for H&E (P = 0.033), and 3.86 for imprint cytology (P = 0.0059). These data validate the enhanced detection of CK-IHC for the evaluation of SLNs. Detection of CK-IHC-positive SLNs appears to warrant CAND in patients with invasive breast cancer. However, the therapeutic value of CAND or adjuvant therapies based on CK-IHC-positive SLNs would be best answered by prospective randomized trials.

Lymphatic mapping and sentinel lymph node biopsy in patients with breast cancer.

The standard of care for the evaluation of axillary nodal involvement remains complete lymph node dissection. Lymphatic mapping and sentinel lymph node (SLN) biopsy are changing this long-held paradigm; indeed, several leading institutions already reserve complete axillary dissection for patients with metastasis to the SLN. In addition to reviewing the literature, this chapter describes our lymphatic mapping experience at the H Lee Moffitt Cancer Center and Research Institute with 1147 breast cancer patients. Our results, in addition to a meta-analysis of data from 12 institutions comprising an additional 1842 patients undergoing complete axillary dissection, demonstrate that SLN biopsy is an accurate method of axillary staging. Although the results from small series may exaggerate the probability of false negative results, the risk of nodal disease based on tumor size and other risk factors should be evaluated when considering the results of SLN sampling.

Two-dimensional representations of the third dimension and their perception by infants.

Many researchers have examined the perception of the third dimension or the preference for three-dimensional versus two-dimensional stimuli in infants, but little is known about infants' representation of the third dimension in a two-dimensional display. Two experiments were conducted to study this capacity. The first experiment was a replication of earlier work, involving a television screen. No difference was observed between looking durations for the 'normal' and 'strange' events in 4-month-olds. As this situation was cognitively complex, a simpler interposition situation was displayed to 3-month-olds in the second experiment. Infants then looked longer at the 'strange' event than at the 'normal' event, suggesting that in a complex situation more perceptual indices must be given to infants. These different data are discussed.

Flock worker's lung: chronic interstitial lung disease in the nylon flocking industry.

BACKGROUND: Two young men working at a nylon flocking plant in Rhode Island developed interstitial lung disease of unknown cause. Similar clusters at the same company's Canadian plant were reported previously. OBJECTIVE: To define the extent, clinicopathologic features, and potential causes of the apparent disease outbreak. DESIGN: Case-finding survey and retrospective cohort study. SETTING: Academic occupational medicine program. PATIENTS: All workers employed at the Rhode Island plant on or after 15 June 1990. MEASUREMENTS: Symptomatic employees had chest radiography, pulmonary function tests, high-resolution computed tomography, and serologic testing. Those with unexplained radiographic or pulmonary function abnormalities underwent bronchoalveolar lavage, lung biopsy, or both. The case definition of "flock worker's lung" required histologic evidence of interstitial lung disease (or lavage evidence of lung inflammation) not explained by another condition. RESULTS: Eight cases of flock worker's lung were identified at the Rhode Island plant. Three cases were characterized by a high proportion of eosinophils (25% to 40%) in lavage fluid. Six of the seven patients who had biopsy had histologic findings of nonspecific interstitial pneumonia, and the seventh had bronchiolitis obliterans organizing pneumonia. All seven of these patients had peribronchovascular interstitial lymphoid nodules, usually with germinal centers, and most had lymphocytic bronchiolitis and interstitial fibrosis. All improved after leaving work. Review of the Canadian tissue specimens showed many similar histologic findings. Among the 165-member study cohort, a 48-fold or greater increase was seen in the sex-adjusted incidence rate of all interstitial lung disease. CONCLUSIONS: Work in the nylon flocking industry poses substantial risk for a previously unrecognized occupational interstitial lung disease. Nylon fiber is the suspected cause of this condition.