A survey of helminth control practices on sheep farms in Great Britain and Ireland.

A telephone survey of 600 farmers throughout Great Britain and Ireland was conducted in order to characterise helminth control practices, and identify factors correlated with perceived anthelmintic failure. Overall, 93% of surveyed farmers routinely treated their sheep against nematodes, 67% against liver fluke and 58% against tapeworms. Anthelmintic resistance in nematodes was perceived by farmers to be present on 10% of farms. Farmers who dosed ewes at mating were more likely to have observed anthelmintic failure, than those who were aware of national guidelines on parasite control. However, objective assessment of anthelmintic efficacy had only been undertaken on 19% of farms. Ewes were treated at mating and lambing on 63% and 62% of farms, respectively. On average, lambs were treated 3.6 times annually, depending on geographical region and on dates of lambing and finishing. Although 'quarantine' treatments were widely administered to bought-in stock, these were appropriately applied in only 3% of cases. This study provides baseline data against which the impact of future anthelmintic information campaigns can be assessed; it will facilitate the development of rational, farm-level mathematical models in support of sustainable parasite control, and will aid in the design of farm management practices that prolong the effective lifespan of novel classes of anthelmintic.

Congenital self-healing reticulohistiocytosis (Hashimoto-Pritzker disease): ten-year experience at Dallas Children's Medical Center.

The real incidence of congenital self-healing reticulohistiocytosis (CSHR) may be underreported because of its high rate of spontaneous resolution and lack of clinical recognition. Currently, there are no criteria other than clinical that can reliably distinguish CSHR from cutaneous involvement by disseminated Langerhans cell histiocytosis (LCH). In this study we investigate the role of E-cadherin, Ki-67, and phosphorylated histone H3 (PHH3) immunohistochemical stains in distinguishing CSHR from disseminated LCH. We found that no significant difference was seen in the histologic features and the expression of E-cadherin, Ki-67, and PHH3 between the two groups; thus supporting the theory that CSHR and LCH represent different ends of a spectrum of the same condition.

Red tides in the Gulf of Mexico: Where, when, and why?

[1] Independent data from the Gulf of Mexico are used to develop and test the hypothesis that the same sequence of physical and ecological events each year allows the toxic dinoflagellate Karenia brevis to become dominant. A phosphorus-rich nutrient supply initiates phytoplankton succession, once deposition events of Saharan iron-rich dust allow Trichodesmium blooms to utilize ubiquitous dissolved nitrogen gas within otherwise nitrogen-poor sea water. They and the co-occurring K. brevis are positioned within the bottom Ekman layers, as a consequence of their similar diel vertical migration patterns on the middle shelf. Upon onshore upwelling of these near-bottom seed populations to CDOM-rich surface waters of coastal regions, light-inhibition of the small red tide of ~1 ug chl l(-1) of ichthytoxic K. brevis is alleviated. Thence, dead fish serve as a supplementary nutrient source, yielding large, self-shaded red tides of ~10 ug chl l(-1). The source of phosphorus is mainly of fossil origin off west Florida, where past nutrient additions from the eutrophied Lake Okeechobee had minimal impact. In contrast, the P-sources are of mainly anthropogenic origin off Texas, since both the nutrient loadings of Mississippi River and the spatial extent of the downstream red tides have increased over the last 100 years. During the past century and particularly within the last decade, previously cryptic Karenia spp. have caused toxic red tides in similar coastal habitats of other western boundary currents off Japan, China, New Zealand, Australia, and South Africa, downstream of the Gobi, Simpson, Great Western, and Kalahari Deserts, in a global response to both desertification and eutrophication.

Hypersensitivity reactions in neonates and infants.

Although rare, several hypersensitivity reactions can occur in the infant population. Several types of hypersensitivity reactions are discussed, including urticaria, drug eruptions, erythema multiforme, allergic contact dermatitis, and vasculitis (acute hemorrhagic edema of infancy); neonatal lupus also is discussed. Although most of these conditions are benign, their presentations can be dramatic and a cause of concern for both parents and physicians. Important considerations and differences in the diagnosis and management of these conditions in children under the age of 6 months are discussed.

X-linked reticulate pigmentary disorder with systemic manifestations: report of a third family and literature review.

Three siblings, two boys and one girl, presented with pigmentary abnormalities. The brothers, ages 11 and 6 years, had diffuse reticulate macular hyperpigmentation with onset in early childhood. In addition, these boys had hypohydrosis, coarse hair with an upswept frontal hairline, failure to thrive, and chronic pulmonary disease. The older boy also had corneal dystrophy and marked photophobia. A punch biopsy specimen from the 11-year-old showed melanophages and necrotic keratinocytes. Stains for amyloid were negative. The sister, age 2 years, had congenital linear hyperpigmented patches involving the intertrigenous areas, but was otherwise normal. The clinical findings of these children were consistent with X-linked reticulate pigmentary disorder with systemic manifestations. We present a summary of the clinical manifestations of this rare disorder and discuss efforts to identify the causative gene.

Primary annular plaque-type psoriasis.

We described two adolescent girls with untreated, consistently annular, plaque-type psoriasis without pustules, a presentation that is to our knowledge, not previously described. No typical confluent plaque-type lesions were present. The plaques in our patients resembled other entities such as tinea corporis and erythema annulare centrifugum, given the erythematous, scaling borders and central clearing. Biopsy specimens from our patients showed features characteristic of psoriasis vulgaris. Both patients responded to combination therapy with calcipotriene and a mid-potency steroid. We conclude that primary annular plaque-type psoriasis shares features of both typical plaque-type and annular pustular psoriasis, suggesting that these entities represent a spectrum of psoriatic disease.

Ichthyosis and keratotic follicular plugs containing dystrophic calcification in newborns: distinctive histopathologic features of x-linked dominant chondrodysplasia punctata (Conradi-Hünermann-Happle syndrome).

Prior to the recent characterization of the enzymatic defect and identification of the involved gene, the histopathology of X-linked dominant chondrodysplasia punctata (Conradi-Hünermann-Happle syndrome or CDPX2) has been described under various names including calcinosis universalis, chondrodystrophia calcificans congenita, Conradi disease, and Conradi-Hünermann syndrome. We present two newborns with characteristic ichthyosiform erythroderma noted at birth. Radiographs demonstrated chondrodysplasia punctata in one patient. Although the x-ray performed at birth was negative in the other patient, sterol analyses of the keratotic scales were diagnostic for CDPX2. Skin biopsies from both patients showed thick laminated orthokeratosis and prominent keratotic follicular plugs containing dystrophic calcification. We also retrospectively examined 20 cases of various types of ichthyosis seen over a 23-year period at our institution. Intracorneal calcium deposition was not seen in any of these cases. As demonstrated by our cases and review of the literature, dystrophic calcification in the keratotic plug is a distinctive histopathologic feature of Conradi-Hünermann-Happle syndrome in newborns and is not seen in other known forms of ichthyoses.

Self-healing juvenile cutaneous mucinosis.

A healthy 14-month-old black girl presented with a 3-week complaint of "knots" on the face and hands. The lesions were acute in onset and asymptomatic. Multiple, firm, nontender, skin-colored to erythematous nodules were noted on the scalp, forehead, axillae, lower legs, abdomen, and hands. A skin biopsy specimen revealed a well-circumscribed accumulation of mucin in the reticular dermis. Colloidal iron stain was positive. Radiographs showed soft tissue prominence only. Serum protein electrophoresis, thyroid function tests, complete blood count, sedimentation rate, and antinuclear antibody were normal, except for lymphocytosis. Findings were consistent with self-healing juvenile cutaneous mucinosis (SHJCM). SHJCM is a condition of unknown etiology characterized by rapid onset of asymptomatic, indurated papules or nodules. Affected children may have arthralgias, but are otherwise well. Spontaneous resolution is the rule. Most skin lesions in our patient had resolved within 6 months of onset. This patient is unique because of the young age of onset.

Rofecoxib-induced instant aquagenic wrinkling of the palms.

An 18-year-old woman presented with a 3-week complaint of exaggerated palmar wrinkling and swelling following brief exposure (1-2 minutes) of her hands to water. She had a history of mixed connective tissue disease and had been started on rofecoxib therapy 1 month prior to the onset of her skin symptoms. Discontinuation of rofecoxib was followed by resolution of symptoms within a period of 3 weeks. Similar palmar skin changes following water exposure have been reported to occur in cystic fibrosis and are thought to be due to increased salt content of the skin and secondary increased water-binding capacity. Rofecoxib is a selective COX-2 inhibitor that has been shown to increase sodium reabsorption in the kidney via effects on prostaglandin E2 and the renal vasculature. The COX-2 protein is also expressed in keratinocytes and plays a role in keratinocyte differentiation. Prostaglandin E2 also plays a role in keratinocyte proliferation and differentiation. Thus rofecoxib may cause increased sodium reabsorption in the skin, as it does in the kidney. The rofecoxib-associated elevation in skin sodium may increase keratin water-binding capacity and cause exaggerated aquagenic wrinkling of the skin, as occurs in cystic fibrosis.

Choroid plexus cysts in the mid-trimester fetus--practical application suggests superiority of an individualized risk method of counseling for trisomy 18.

OBJECTIVES: Analysis of a referral population of patients with choroid plexus cysts (CPCs) was performed to compare an average risk method of counseling to an individualized risk method. METHODS: A total of 395 patients referred to a Prenatal Diagnosis Center were included, of whom 341 had isolated CPCs and 54 had associated ultrasound abnormalities. For isolated CPCs, an average risk of 1/150 for aneuploidy was compared to an individualized risk assessment [prior risk as determined by maternal age or serum screening multiplied by the likelihood ratio established by Gupta et al. (1997)]. Accuracy, cost, and procedure-related losses were assessed. RESULTS: Both methods resulted in 100% sensitivity. The individualized method resulted in greater specificity, decreased costs, and (theoretically) fewer procedure-related pregnancy losses. CONCLUSIONS: An individualized risk method of counseling utilizing the likelihood ratios established by Gupta et al. (1997) was superior to an average risk method for assessing trisomy 18 risk in the setting of CPC detected in mid-trimester.

Retrieval of chlorophyll from remote-sensing reflectance in the china seas.

The East China Sea is a typical case 2 water environment, where concentrations of phytoplankton pigments, suspended matter, and chromophoric dissolved organic matter (CDOM) are all higher than those in the open oceans, because of the discharge from the Yangtze River and the Yellow River. By using a hyperspectral semianalytical model, we simulated a set of remote-sensing reflectance for a variety of chlorophyll, suspended matter, and CDOM concentrations. From this simulated data set, a new algorithm for the retrieval of chlorophyll concentration from remote-sensing reflectance is proposed. For this method, we took into account the 682-nm spectral channel in addition to the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) channels. When this algorithm was applied to a field data set, the chlorophyll concentrations retrieved through the new algorithm were consistent with field measurements to within a small error of 18%, in contrast with that of 147% between the SeaWiFS ocean chlorophyll 2 algorithm and the in situ observation.

Atmospheric Correction of SeaWiFS Imagery: Assessment of the Use of Alternative Bands.

Spatial inhomogeneity, or speckling, frequently occurs in Sea-viewing Wide Field-of-view Sensor (SeaWiFS) data products such as water-leaving radiance and chlorophyll concentration. We have found that this effect may be caused by high-altitude aerosols or thin cirrus clouds or even by digitization errors. For the scenes evaluated, whitecaps were ruled out as a likely cause of these errors. We tried to avoid using the 765-nm band, which is affected by O(2) absorption and is more sensitive to digitization errors, by instead using the 670-nm band in the atmospheric correction and found that speckling for either cloud-free areas or cloud-adjacent areas was significantly reduced.

Band-ratio or spectral-curvature algorithms for satellite remote sensing?

For the retrieval of chlorophyll concentrations or the total absorption coefficients of oceanic waters based on water color, there are algorithms that use either band ratios or spectral curvatures of remote-sensing reflectance or water leaving radiance. We show that band-ratio algorithms have the potential to be applied to a wider dynamic range of oceanic waters, whereas spectral-curvature algorithms show stable performance as long as the data set falls within the appropriate range.

Hyperspectral remote sensing for shallow waters. 2. Deriving bottom depths and water properties by optimization.

In earlier studies of passive remote sensing of shallow-water bathymetry, bottom depths were usually derived by empirical regression. This approach provides rapid data processing, but it requires knowledge of a few true depths for the regression parameters to be determined, and it cannot reveal in-water constituents. In this study a newly developed hyperspectral, remote-sensing reflectance model for shallow water is applied to data from computer simulations and field measurements. In the process, a remote-sensing reflectance spectrum is modeled by a set of values of absorption, backscattering, bottom albedo, and bottom depth; then it is compared with the spectrum from measurements. The difference between the two spectral curves is minimized by adjusting the model values in a predictor-corrector scheme. No information in addition to the measured reflectance is required. When the difference reaches a minimum, or the set of variables is optimized, absorption coefficients and bottom depths along with other properties are derived simultaneously. For computer-simulated data at a wind speed of 5 m/s the retrieval error was 5.3% for depths ranging from 2.0 to 20.0 m and 7.0% for total absorption coefficients at 440 nm ranging from 0.04 to 0.24 m(-1). At a wind speed of 10 m/s the errors were 5.1% for depth and 6.3% for total absorption at 440 nm. For field data with depths ranging from 0.8 to 25.0 m the difference was 10.9% (R2 = 0.96, N = 37) between inversion-derived and field-measured depth values and just 8.1% (N = 33) for depths greater than 2.0 m. These results suggest that the model and the method used in this study, which do not require in situ calibration measurements, perform very well in retrieving in-water optical properties and bottom depths from above-surface hyperspectral measurements.

Satellite-sensor calibration verification with the cloud-shadow method.

An atmospheric-correction method appropriate for high-spatial-resolution sensors that uses cloud-shaded pixels together with pixels in a neighboring region of similar optical properties is described. This cloud-shadow method uses the difference between the total radiance values observed at the sensor for these two regions, thus removing the nearly identical atmospheric radiance contributions to the two signals (e.g., path radiance and Fresnel-reflected skylight). What remains is largely due to solar photons backscattered from beneath the sea to dominate the residual signal. Normalization by the direct solar irradiance reaching the sea surface and correction for some second-order effects provides the remote-sensing reflectance of the ocean at the location of the neighbor region, providing a known ground target spectrum for use in testing the calibration of the sensor. A similar approach may be useful for land targets if horizontal homogeneity of scene reflectance exists about the shadow. Monte Carlo calculations have been used to correct for adjacency effects and to estimate the differences in the skylight reaching the shadowed and neighbor pixels.