Regional target loads of atmospheric nitrogen and sulfur deposition for the protection of stream and watershed soil resources of the Adirondack Mountains, USA

Acidic deposition contributes to a range of environmental impacts across forested landscapes, including acidification of soil and drainage water, toxic aluminum mobilization, depletion of available soil nutrient cations, and impacts to forest and aquatic species health and biodiversity. In response to decreasing levels of acidic deposition, soils and drainage waters in some regions of North America have become gradually less acidic. Thresholds of atmospheric deposition at which adverse ecological effects are manifested are called critical loads (CLs) and/or target loads (TLs). Target loads are developed based on approaches that account for spatial and temporal aspects of acidification and recovery. Exceedance represents the extent to which current or projected future levels of acidic deposition exceed the level expected to cause ecological harm. We report TLs of sulfur (S) and nitrogen (N) deposition and the potential for ecosystem recovery of watershed soils and streams in the Adirondack region of New York State, resources that have been less thoroughly investigated than lakes. Regional TLs were calculated by statistical extrapolation of hindcast and forecast simulations of 25 watersheds using the process-based model PnET-BGC coupled with empirical observations of stream hydrology and established sensitivity of sugar maple (Acer saccharum) to soil base saturation and brook trout (Salvelinus fontinalis) to stream acid neutralizing capacity (ANC). Historical impacts and the expected recovery timeline of regional soil and stream chemistry and fish community condition within the Adirondack Park were evaluated. Analysis suggests that many low-order Adirondack streams and associated watershed soils have low TLs (<40 meq/m²/yr of N + S deposition) to achieve specified benchmarks for recovery of soil base saturation or stream ANC. Acid-sensitive headwater and low-order streams and watershed soils in the region are expected to experience continued adverse effects from N and S deposition well into the future even under aggressive emissions reductions. Watershed soils and streams in the western Adirondack Park are particularly vulnerable to acidic deposition and currently in exceedance of TLs. The methods used for linking statistical and process-based models to consider chemical and biological response under varying flow conditions at the regional scale in this study can be applied to other areas of concern.

A synthesis of patterns of environmental mercury inputs, exposure and effects in New York State

Mercury (Hg) pollution is an environmental problem that adversely affects human and ecosystem health at local, regional, and global scales-including within New York State. More than two-thirds of the Hg currently released to the environment originates, either directly or indirectly, from human activities. Since the early 1800s, global atmospheric Hg concentrations have increased by three- to eight-fold over natural levels. In the U.S., atmospheric emissions and point-source releases to waterways increased following industrialization into the mid-1980s. Since then, water discharges have largely been curtailed. As a result, Hg emissions, atmospheric concentrations, and deposition over the past few decades have declined across the eastern U.S. Despite these decreases, Hg pollution persists. To inform policy efforts and to advance public understanding, the New York State Energy Research and Development Authority (NYSERDA) sponsored a scientific synthesis of information on Hg in New York State. This effort includes 23 papers focused on Hg in atmospheric deposition, water, fish, and wildlife published in Ecotoxicology. New York State experiences Hg contamination largely due to atmospheric deposition. Some landscapes are inherently sensitive to Hg inputs driven by the transport of inorganic Hg to zones of methylation, the conversion of inorganic Hg to methylmercury, and the bioaccumulation and biomagnification along food webs. Mercury concentrations exceed human and ecological risk thresholds in many areas of New York State, particularly the Adirondacks, Catskills, and parts of Long Island. Mercury concentrations in some biota have declined in the Eastern Great Lakes Lowlands and the Northeastern Highlands over the last four decades, concurrent with decreases in water releases and air emissions from regional and U.S. sources. However, widespread changes have not occurred in other ecoregions of New York State. While the timing and magnitude of the response of Hg levels in biota varies, policies expected to further diminish Hg emissions should continue to decrease Hg concentrations in food webs, yielding benefits to the fish, wildlife, and people of New York State. Anticipated improvements in the Hg status of aquatic ecosystems are likely to be greatest for inland surface waters and should be roughly proportional to declines in atmospheric Hg deposition. Efforts that advance recovery from Hg pollution in recent years have yielded significant progress, but Hg remains a pollutant of concern. Indeed, due to this extensive compilation of Hg observations in biota, it appears that the extent and intensity of the contamination on the New York landscape and waterscape is greater than previously recognized. Understanding the extent of Hg contamination and recovery following decreases in atmospheric Hg deposition will require further study, underscoring the need to continue existing monitoring efforts.

Co-infection as a confounder for the role of Clostridium difficile infection in children with diarrhoea: a summary of the literature

Although Clostridium difficile is a major cause of antibiotic-associated diarrhoea in adults, the incidence and severity of C. difficile infection (CDI) in children is unclear. One complicating factor in assessing the role of CDI in children is the possibility of co-infection with other gastrointestinal pathogens. In this review, we summarise the literature concerning C. difficile co-infections in young children, in an attempt to discuss the rate of co-infections and their potential role in the severity of CDI clinical presentation. We identified 31 studies where co-infections were analysed, comprising 1,718 patients with positive C. difficile tests. The pooled percentage of reported co-infections was 20.7% (range 0-100%). Viral co-infections were most commonly reported (46%), with bacteria and parasites accounting for 14.9% and 0.01% of cases, respectively. However, the panel of co-infections tested for varied considerably among studies and 38% of stated co-infections did not have a pathogen reported. Substantial variation in how and when tests for gastrointestinal co-infections are carried out, small sample sizes and a lack of clear CDI case definitions preclude meaningful conclusions on the true rate of co-infections in this patient population. This review suggests that co-infections may be common in children with diarrhoea who tested positive for C. difficile. Given a lack of CDI case definitions, especially in young children under the age of 5 years, a broad panel of pathogens should be tested for to exclude other microbiological causes. However, the summarised poor quality of the available literature on this subject highlights a need for further studies.

Nitrogen isotopes as indicators of NO(x) source contributions to atmospheric nitrate deposition across the midwestern and northeastern United States

Global inputs of NO(x) are dominated by fossil fuel combustion from both stationary and vehicular sources and far exceed natural NO(x) sources. However, elucidating NO(x) sources to any given location remains a difficult challenge, despite the need for this information to develop sound regulatory and mitigation strategies. We present results from a regional-scale study of nitrogen isotopes (delta15N) in wet nitrate deposition across 33 sites in the midwestern and northeastern U.S. We demonstrate that spatial variations in delta15N are strongly correlated with NO(x) emissions from surrounding stationary sources and additionally that delta15N is more strongly correlated with surrounding stationary source NO(x) emissions than pH, SO4(2-), or NO3- concentrations. Although emission inventories indicate that vehicle emissions are the dominant NO(x) source in the eastern U.S., our results suggest that wet NO3- deposition at sites in this study is strongly associated with NO(x) emissions from stationary sources. This suggests that large areas of the landscape potentially receive atmospheric NO(y) deposition inputs in excess of what one would infer from existing monitoring data alone. Moreover, we determined that spatial patterns in delta15N values are a robust indicator of stationary NO(x) contributions to wet NO3- deposition and hence a valuable complement to existing tools for assessing relationships between NO3- deposition, regional emission inventories, and for evaluating progress toward NO(x) reduction goals.

Child restraint systems: an update for physicians

During the past decade, many advances have been made in motor vehicle safety restraint systems, and these advancements have brought changes in the recommendations for child passenger safety. In spite of these advances, a high morbidity and mortality rate continues to be attributed to improper or absent child restraint use. Child transportation safety is a complex issue. Lack of public awareness and incomplete laws contribute to the confusion. The solution involves professional and public education, further technological advances, and advocacy for improved legislation and regulation. Physicians have a unique opportunity to incorporate advice about proper restraint use into their daily practice; however, that requires a clear understanding of the current recommendations. Both the age and weight of the child determine the appropriate child restraint system. Understanding, practicing, and promoting these recommendations will save lives. This article reviews the current recommendations for proper child restraint while traveling in a motor vehicle.

Effect of endodontic sealers on dowels luted with resin cement

PURPOSE

This study evaluated the retention of prefabricated parallel-sided dowels luted with resin cement in extracted teeth that were obturated with gutta percha using a eugenol sealer or a calcium hydroxide sealer.

MATERIALS AND METHODS

Extracted maxillary incisor roots (N = 51) were instrumented to simulate conventional root canal therapy and divided into 3 groups (n = 17). One group was not obturated. Second and third groups were obturated with gutta percha using a eugenol-containing or calcium hydroxide-containing sealer. Gutta percha was removed using a heated plugger, and dowel spaces were prepared to a 7 mm depth. Dowel space walls were acid etched and primed, and prefabricated stainless steel dowels were luted using resin cement. After 24 hours, the load required to dislodge each dowel along a path parallel to its long axis was measured and recorded. A one-way analysis of variance (alpha = 0.05) was performed to identify differences in the means among groups. The incidence of failure within the cement or at the dentin-cement interface was also recorded.

RESULTS

No statistically significant difference was found among the control (159.9 +/- 96.3 N), eugenol sealer (153.1 +/- 77.3 N), and calcium hydroxide sealer (192.0 +/- 89.3 N) groups. Nearly all specimens displayed adhesive failure at the dentin-resin cement interface.

CONCLUSIONS

Conventional endodontic obturation using a eugenol-containing or a calcium hydroxide-containing endodontic sealer did not affect retention of prefabricated stainless steel dowels luted with resin cement.

Extensive psoriasis induced by interferon alfa treatment for chronic hepatitis C

A 47 year old man with chronic hepatitis C was treated with interferon alfa, 3 million units three times a week, and developed widespread plaque psoriasis within weeks of starting interferon therapy. There was no previous history of psoriasis. The psoriasis was characterised by extensive nail involvement and plaques at the interferon injection sites. The patient relapsed after a total of 12 months of interferon and was subsequently treated with interferon and tribavirin (ribavirin) with recurrence of the psoriasis.

Successful treatment of acquired perforating dermatosis with rifampicin in an Asian patient with sclerosing cholangitis

Acquired perforating dermatosis (APD) is a very rare disorder which has been described in association with systemic diseases such as diabetes mellitus, HIV infection or lymphoma. In this report we describe a patient with APD associated with sclerosing cholangitis and diabetes mellitus who was successfully treated with rifampicin. A 33-year-old Indian woman with a history of extensive pancreatic surgery, sclerosing cholangitis and insulin dependent diabetes mellitus was referred to our unit with intractable pruritus. She was treated with cholestyramine, ursodeoxycholic acid, several analgesics, UVB therapy, topical steroids, sedative antihistamines and plasmapheresis without significant improvement. Increasingly severe itching was associated with papular skin changes limited initially to the lower limbs but which later involved her entire body. Biopsy of a representative lesion showed the changes of APD. She was subsequently treated with rifampicin which produced a dramatic resolution of pruritus within 3 weeks and the skin changes progressively resolved over subsequent months. In this newly described association of APD with sclerosing cholangitis, rifampicin treatment appeared to be efficient in ameliorating pruritus and the papular skin changes typical of APD.

Biologic properties of human herpesvirus 7 strain SB

The growth characteristics of human herpesvirus 7 strain SB (HHV-7 (SB)) were studied in human umbilical cord blood lymphocyte (CBL) cultures. The virus has approximately a 4-day growth cycle, as measured by immunofluorescence analysis, quantitation of the relative viral DNA concentration, and examination of infected cells by electron microscopy on consecutive days post-infection. By systematically varying the culture media components, improved culturing conditions were established. Activated lymphocytes were required for virus growth. HHV-7(SB) grew best in phytohemagglutinin-stimulated CBL cultured in media containing 0.01 mg/ml hydrocortisone. Addition of recombinant human interleukin 2 (IL-2) at concentrations exceeding 1-10 U/ml inhibited virus growth in most CBL cultures. Addition of exogenous IL-2 to the culture media had no effect on viral DNA production. However, the percentage of virus antigen-positive cells was highest when 0.1-1 U/ml was added to the media. Differences in the ability of individual CBL cultures to replicate HHV-7(SB) was not explained by differing CD4+ cell concentrations. However, individual cultures varied in the level of endogenous IL-2 production, which may contribute to the virus growth variability in CBL. HHV-7(SB) grew in the CD4-positive T-cell line SupT1, but not in a variety of other lymphocyte, fibroblast, or epithelial cell lines. Nine compounds were tested for antiviral activity against HHV-7 in vitro. Phosphonoformic acid inhibited virus growth with a 50% effective concentration of 4.8 microM. Ganciclovir (200 microM) and phosphonoacetic acid (100 microM) inhibited more than 90% of virus production. None of the compounds were cytotoxic at concentrations which inhibited the virus. A generalized increase in host cell protein synthesis was also observed in virus-infected cells similar to that seen in CBL infected with human herpesvirus 6.

Accelerating the pace of luciferase reporter gene assays

Luciferase reporter gene assays have gained more importance because of their easy readout, high sensitivity and lack of environmental waste disposal problems. However, several obstacles remain that have prohibited a wider use and the implementation of this type of assay in high-throughput screening programs: (i) Measurements need to be carried out within an active enzyme reaction, and the assessment of such reactions are time-dependent; (ii) the signal produced has a "flash" type characteristic and therefore requires specialized equipment for measurement; and (iii) side-reactions can occur that interact with the signal readout of the assay in a non-reproducible way. These hurdles make an otherwise convenient assay principle troublesome for larger-scale screening use. We have attempted to overcome these problems by different means, leading to the development of LucLite, a stable signal homogeneous reagent system. This system allows use in a higher throughput screening capacity and enables the use of standard scintillation/luminescence instruments.

Nitrate and nitric acid concentrations at two Rocky Mountain baseline monitoring sites

A two-tiered, Teflon/nylon filterpack system was used to characterize spatial and temporal patterns of particulate nitrates and nitric acid vapors at two monitoring sites in the Rocky Mountains. Geometric means for particulate nitrates were 38.9 and 52.8 ng/m(3) for the upper and lower sites, respectively. For nitric acid, geometric means of 70.4 ng/m(3) for the upper site and 295 ng/m(3) for the lower site were observed. The relatively low concentrations found at these two sites are comparable to published values for these materials at other remote sites. Atmospheric concentrations of nitrates and nitric acid were correlated significantly at each site, and the total nitrate concentrations (NO(3)(-) plus HNO(3)) were correlated between sites. Comparisons between the two sites indicate that nitric acid concentrations were statistically greater at the lower elevation site, whereas nitrate concentrations were not significantly different. No general seasonal or annual pattern of nitrate or nitric acid concentrations were evident when comparable sampling periods were examined.

Bullous pemphigoid following radiotherapy

We report the case of a 57-year-old woman who developed bullous pemphigoid 3 weeks after electron beam radiotherapy. The bullae were confined to the area of the radiation field and responded to topical clobetasol propionate 0.05% cream (Dermovate). This is the second case of bullous pemphigoid confined to an area of previous radiotherapy. Radiotherapy may be a rare trigger for the development of bullous pemphigoid.

Pemphigoid nodularis: a report of two cases

Pemphigoid nodularis is a rare variant of bullous pemphigoid characterized by the development of pruritic hyperkeratotic nodules. These nodules may be the presenting feature of the disease, and may precede the development of bullae by several years. The condition appears to be more common in females than males, and is often resistant to treatment. We report two definite cases and one possible case of pemphigoid nodularis, and review the literature relating to this disorder.

Neonatal lupus erythematosus with persistent telangiectasia and spastic paraparesis

A case of neonatal lupus erythematosus with cutaneous and neurological features is reported. At 5 years of age, the patient retains residual telangiectatic lesions over the trunk and face and has mild spastic diplegia, originally detected at the age of 1 year. Persistent telangiectasia is now a recognized feature of neonatal lupus erythematosus. The pathogenesis of the neurological deficit is uncertain.

Diffuse primary cutaneous amyloidosis

A case of extensive primary cutaneous amyloidosis exhibiting both macular and lichenoid lesions is reported. Lesions were arranged in a distinctive linear pattern covering much of the trunk and limbs, in places following Blaschko's lines. The coexistence of macular and lichenoid lesions suggests that this is an unusual variant of biphasic cutaneous amyloidosis.

A potpourri of parasites in poetry and proverb

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Juvenile spring eruption of the ears: a probable variant of polymorphic light eruption

We report 18 cases in which a pruritic, erythematous, papular and vesicular eruption developed on the ears following sun exposure. Four of these patients had, on other occasions, suffered from typical polymorphic light eruption. The clinical features, histological changes, and results of phototesting suggest that juvenile spring eruption of the ears is a localized form of polymorphic light eruption.

Lichen sclerosus et atrophicus--a review of 15 cases in young girls

We report a series of 15 girls who developed lichen sclerosus between the ages of 18 months and 9 years. Only five of these were initially referred to a dermatologist and the diagnosis was made promptly in these cases on the first visit to the clinic. The diagnosis was usually delayed under disciplines less familiar with the disease. We encountered a high level of parental anxiety regarding the possibility of misdiagnosis of lichen sclerosus as childhood sexual abuse. Dysuria and pain on defaecation were common and prominent symptoms which have not previously been stressed adequately. The clinical features were diagnostic in all our cases, although three had undergone vulval biopsy under general anaesthesia prior to being seen by a dermatologist. There was a trend towards improvement with increasing age.

Stress distribution surrounding endodontic posts

This study compared the stress distribution during insertion and function of three prefabricated endodontic posts with different designs using the criteria of post length and diameter. Test blocks of photoelastic material were prepared with simulated endodontic canals. Three posts for each design, diameter, and depth were cemented. Each specimen was examined and photographed without load, with 135 Newton (N) compressive force, and with 90 N and/or 135 N oblique force applied at 26 degrees by use of a circular polariscope. Para-Post and Para-Post Plus posts produced similar, evenly distributed patterns of stress using the criteria of diameter, depth, and load. Flexi-Post posts produced asymmetric stress patterns with concentration of stress at each thread. During compressive loading and after cementation alone, Flexi-Post posts displayed significantly higher shoulder stresses and substantially greater stresses along the coronal surface of the post's length than Para-Post and Para-Post Plus posts. Apical stresses were similar for Flexi-Post, Para-Post, and Para-Post Plus posts during compressive loading.

Neurological complications of systemic sclerosis--a report of three cases and review of the literature

We report three cases of systemic sclerosis demonstrating four different neurological complications: trigeminal neuropathy, peripheral neuropathy, carpal-tunnel syndrome and prolonged response to local anaesthesia. A review of the literature reveals a wide range of neurological abnormalities associated with systemic sclerosis. When they occur, these are often presenting features.

Juvenile spring eruption of the ears

We report two patients with a distinctive bullous photodermatosis conforming to the previously described entity, 'juvenile spring eruption of the ears'. This is an unusual bullous photodermatosis, which develops over the light exposed areas of the ears, usually in the spring. Boys and young male adults are most commonly affected. Juvenile spring eruption receives scant attention in dermatological texts, and to our knowledge no cases have been reported in the English literature since 1954.

Prolidase deficiency: a case report and literature review

We describe a patient in whom chronic leg ulceration was due to prolidase deficiency. The clinical features of this condition are described and we discuss the metabolic abnormality and the treatment regimes which have been employed. We also report the further finding of erosive cystitis, which we consider should be added to the list of clinical features of prolidase deficiency.

Lichen sclerosus

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Dietary manipulation in childhood atopic dermatitis

The dietary habits of 73 children seen consecutively in a dermatology out-patient department were studied to ascertain the nature and frequency of dietary manipulation and to assess any potential hazards. Although most children had only mild flexural dermatitis, 71% had had significant alterations made to their diet before attendance at hospital. Almost all diets were unsupervised and only six children had seen a dietitian. Over half had been started on diets before any professional advice had been sought. Information on diet had come from media, books or magazines (51%), friends (32%), general practitioners (27%) and district nurses or health visitors (18%). The major dietary alterations included the exclusion of eggs, dairy products and food additives, and the use of soya and goat's milk. Under 10% of patients claimed benefit from these largely unsupervised diets. Harmful practices included the frequent use of unboiled, unpasteurized goat's milk, unmodified goat's milk in a baby of 4 months and the use of severely restricted diets. Three children (6%) in the diet group had been on diets which were considered by a hospital dietitian to be particularly dangerous. However, there was no evidence of growth retardation, failure to thrive or specific deficiency syndromes in the group we studied. Uncontrolled, unsupervised and often prolonged dietary alterations are commonplace in children with atopic dermatitis. This is a potentially serious health problem.

Ectopic cutaneous schistosomiasis and schistosomal ocular inflammatory disease

We describe a patient with unilateral ectopic cutaneous schistosomiasis as a feature of Schistosoma mansoni infection. In addition to skin lesions he also suffered from schistosomal ocular inflammatory disease. The infection appeared to have been acquired during a visit to Tanzania. Ectopic cutaneous lesions usually affect the perineal area or trunk, and our patient is unusual in the localization of his skin lesions to the forehead.

An outbreak of scabies in a residential home

An outbreak of scabies in a residential home for the elderly is described, and the investigation and management of the problem discussed. Multiple cases of scabies in this type of community are almost invariably associated with the presence of an unrecognized case of crusted (Norwegian) scabies. Unless such an individual is recognized, attempts to eradicate the problem may prove unsuccessful.