Overview of surface measurements and spatial characterization of submicrometer particulate matter during the DISCOVER-AQ 2013 campaign in Houston, TX.

The sources of submicrometer particulate matter (PM1) remain poorly characterized in the industrialized city of Houston, TX. A mobile sampling approach was used to characterize PM1 composition and concentration across Houston based on high-time-resolution measurements of nonrefractory PM1 and trace gases during the DISCOVER-AQ Texas 2013 campaign. Two pollution zones with marked differences in PM1 levels, character, and dynamics were established based on cluster analysis of organic aerosol mass loadings sampled at 16 sites. The highest PM1 mass concentrations (average 11.6 ± 5.7 µg/m3) were observed to the northwest of Houston (zone 1), dominated by secondary organic aerosol (SOA) mass likely driven by nighttime biogenic organonitrate formation. Zone 2, an industrial/urban area south/east of Houston, exhibited lower concentrations of PM1 (average 4.4 ± 3.3 µg/m3), significant organic aerosol (OA) aging, and evidence of primary sulfate emissions. Diurnal patterns and backward-trajectory analyses enable the classification of airmass clusters characterized by distinct PM sources: biogenic SOA, photochemical aged SOA, and primary sulfate emissions from the Houston Ship Channel. Principal component analysis (PCA) indicates that secondary biogenic organonitrates primarily related with monoterpenes are predominant in zone 1 (accounting for 34% of the variability in the data set). The relevance of photochemical processes and industrial and traffic emission sources in zone 2 also is highlighted by PCA, which identifies three factors related with these processes/sources (~50% of the aerosol/trace gas concentration variability). PCA reveals a relatively minor contribution of isoprene to SOA formation in zone 1 and the absence of isoprene-derived aerosol in zone 2. The relevance of industrial amine emissions and the likely contribution of chloride-displaced sea salt aerosol to the observed variability in pollution levels in zone 2 also are captured by PCA. IMPLICATIONS: This article describes an urban-scale mobile study to characterize spatial variations in submicrometer particulate matter (PM1) in greater Houston. The data set indicates substantial spatial variations in PM1 sources/chemistry and elucidates the importance of photochemistry and nighttime oxidant chemistry in producing secondary PM1. These results emphasize the potential benefits of effective control strategies throughout the region, not only to reduce primary emissions of PM1 from automobiles and industry but also to reduce the emissions of important secondary PM1 precursors, including sulfur oxides, nitrogen oxides, ammonia, and volatile organic compounds. Such efforts also could aid in efforts to reduce mixing ratios of ozone.

A 6-month maintenance therapy with adapalene-benzoyl peroxide gel prevents relapse and continuously improves efficacy among patients with severe acne vulgaris: results of a randomized controlled trial.

BACKGROUND: Acne vulgaris is a chronic and frequently recurring disease. A fixed-dose adapalene-benzoyl peroxide (adapalene-BPO) gel is an efficacious and safe acne treatment. OBJECTIVES: To assess the long-term effect of adapalene-BPO on relapse prevention among patients with severe acne after successful initial treatments. METHODS: This is a multicentre, double-blind, randomized and controlled study. In total, 243 subjects who had severe acne vulgaris and at least 50% global improvement after a previous 12-week treatment were randomized into the present study to receive adapalene-BPO gel or its vehicle once daily for 24 weeks. RESULTS: At week 24, compared with vehicle, adapalene-BPO resulted in significantly higher lesion maintenance success rate (defined as having at least 50% improvement in lesion counts achieved in initial treatment) for all types of lesions (total lesions: 78·9% vs. 45·8%; inflammatory lesions: 78·0% vs. 48·3%; noninflammatory lesions: 78·0% vs. 43·3%; all P < 0·001). Significantly more subjects with adapalene-BPO than with vehicle had the same or better Investigator's Global Assessment score at week 24 than at baseline (70·7% vs. 34·2%; P < 0·001). The time when 25% of subjects relapsed was 175 days with adapalene-BPO and 56 days with vehicle (17 weeks earlier; P < 0·0001). Adapalene-BPO led to further decrease of lesion counts during the study and 45·7% of subjects were 'clear' or 'almost clear' at week 24. It was also safe and well tolerated in the study. CONCLUSIONS: Adapalene-BPO not only prevents the occurrence of relapse among patients with severe acne, but also continues to reduce disease symptoms during 6 months.

Antenatal corticosteroids for the prevention of neonatal respiratory distress in a predominantly rural state Medicaid population.

OBJECTIVE: To examine the use of prenatal intramuscular steroids in a community setting as outlined in National Institutes of Health (NIH) guidelines to reduce respiratory distress syndrome in premature infants. METHODS: We performed a complete chart review for 1 year of deliveries to Medicaid mothers at 25-34 weeks' gestation at all obstetric units in Arkansas, analyzing time of arrival to the hospital, time of delivery, and dosage, and route of steroid administration to compare processes between community and teaching center sites, and general performance with NIH guidelines. RESULTS: Of 191 deliveries at 25-34 weeks' gestation, 63.4% of mothers received at least one dose of corticosteroids before delivery. Only 124 (65%) of these mothers presented to the hospital more than 4 hours before delivery and 87% of these mothers received at least one dose of corticosteroids before delivery. Ninety percent of women who were transferred after presenting in labor and 94.9% of women who delivered at the tertiary care referral center received corticosteroids. There was no statistically significant difference in corticosteroid administration rates for women with or without preterm premature rupture of membranes. Many women received corticosteroids at dosages and intervals disparate with NIH guidelines. CONCLUSION: Obstetric providers in Arkansas administered antenatal steroids to Medicaid women in preterm labor at a rate higher than stated in previous literature. Delivery at a nonreferral center or within 4 hours of arrival to the hospital were associated with reduced antenatal corticosteroid administration. Improved performance efforts should target institutional usage and behavior of mothers at risk for premature delivery.

Erythema nodosum leprosum: nature and extent of the cutaneous microvascular alterations.

Skin biopsy specimens from four patients with erythema nodosum leprosum, when examined as Epon-embedded, 1-micron sections, exhibited a necrotizing vasculitis involving capillaries, venules, and small-to-medium arteries and veins. In the superficial dermis, affected venules and capillaries showed endothelial cell enlargement and focal necrosis associated with perivascular infiltrates of lymphocytes. In the deep dermis and subcutaneous tissue, affected venules, arterioles, and arteries exhibited endothelial cell necrosis and matted fibrin in the vessel walls associated with perivascular infiltrates of neutrophils. Throughout the dermis, mononuclear phagocytes with vacuoles containing numerous fragmented organisms were observed. By electron microscopy, electron-dense material resembling immune complexes was observed in the walls of these vessels. These observations support the concept that erythema nodosum leprosum is an immune complex-mediated necrotizing vasculitis involving capillaries, arterioles, arteries, venules, and veins.

Clinical and histopathologic spectrum of necrotizing vasculitis. Report of findings in 101 cases.

Clinical and histopathologic features of 101 cases of necrotizing vasculitis were selected on the basis of the following histopathologic criteria: fibrinoid necrosis of blood vessel walls, endothelial cell hyperplasia, and an infiltrate within and around the blood vessel walls predominantly of polymorphonuclear leukocytes. There were three clinical patterns of vasculitis: (1) associated with other coexistent disease, (2) associated with known precipitating events, and (3) idiopathic. Two histologic features were particularly notable in view of the clinical findings. First, vasculitis extending deep into the reticular dermis or subcutaneous tissue seemed to be associated more often with systemic disease such as malignancy or connective tissue disease. Second, in biopsy specimens from patients with hypocomplementemia, the inflammatory infiltrate was composed almost exclusively of neutrophils, as compared with the mixed infiltrate seen in normocomplementemic vasculitis.

Subcorneal pustular dermatosis and pustular psoriasis. A clinicopathologic correlation.

The relationship between subcorneal pustular dermatosis (SCPD) and pustular psoriasis is discussed on the basis of a study of 23 patients with SCPD seen at the Mayo Clinic, Rochester, Minn, since 1956. In seven of the 23 patients, pustular psoriasis subsequently developed, and in three other patients there was associated psoriasis vulgaris. It was impossible to make a histopathologic distinction between SCPD and some cases of pustular psoriasis. The response to therapy with sulfones was erratic, if not ineffective. Our data suggest that disease identical to SCPD is, in many instances, strongly associated biologically, clinically, and histopathologically with psoriasis, and that continued observation of the clinical course may further substantiate this relationship in many cases.

Vitiligolike macules in systemic scleroderma.

Changes of hyperpigmentation and depigmentation in systemic scleroderma have been known since the last century, but their relationship to the pathogenesis of the condition is poorly understood. Clinical, histologic, histochemical, immunopathologic, and electron microscopic studies of the depigmented lesions in seven patients with systemic scleroderma demonstrated changes similar to those of vitiligo, but with subtle differences. Immunologic mechanisms seem to be involved in the induction of depigmentation in both vitiligo and systemic scleroderma.

Primary neuroendocrine carcinomas of the skin (Merkel cell tumors). A clinical, histologic, and ultrastructural study of thirteen cases.

Neuroendocrine carcinomas of the skin have recently been recognized, and clinicopathologic information on these tumors is accumulating rapidly. We studied 13 such lesions by light and electron microscopy, and eight were subjected to immunohistochemical analysis. The ages of the patients (five women and eight men) ranged from 24 to 84 years. Nine patients had neoplasms occurring in sun-exposed areas; one patient had metachronous symmetric lesions on the arms, and another had antecedent hypohidrotic ectodermal dysplasia. Eight tumors metastasized, and six spread to regional or distant lymph nodes. Three patients died with visceral metastases to the liver, bones, and brain. All patients had their primary tumor confined to the corium and subcutaneous tissue without involvement of overlying epidermis. Tumor cells were round and uniform in size, with delicate nuclear chromatin and a high mitotic rate. An organoid growth pattern was seen in all tumors, with focal trabeculation and rare rosette formation. Ultrastructurally, peripheral cytoplasmic dense-core granules were evident, and perinuclear filament whorls could be seen in all 13 tumors. The latter feature was stable, even in specimens taken from paraffin blocks for electron microscopy. Immunoperoxidase studies failed to reveal serotonin, calcitonin, or adrenocorticotrophin within tumor cells.

Cutaneous malignant histiocytosis: a clinical and histopathologic study of eight cases, with immunohistochemical analysis.

Eight cases of autopsy-proved malignant histiocytosis (MH) are reported, in which cutaneous involvement was a prominent finding at initial clinical presentation. In two patients, the disease remained confined to the skin for significant periods before systemic dissemination appeared. Immunohistochemical analysis of cutaneous infiltrates of MH showed uniform negativity of the atypical cells for lysozyme, immunoglobulin light chain, glycogen, and chloroacetate esterase content. In five cases, cytochemical stains for acid phosphatase, butyrate (nonspecific) esterase, chloroacetate esterase, and peroxidase activity were performed on bone marrow aspirates containing malignant cells; all demonstrated diffuse positivity for acid phosphatase and nonspecific esterase, and negativity for peroxidase and chloroacetate esterase. Touch-imprint preparations of cutaneous lesions in one of these cases yielded identical results. These findings indicate that cytochemical methods are preferable to immunohistochemical technics in identification of histiocytic malignancies and that foci of skin involvement may provide a useful source for such diagnostic evaluation.

The clinicopathologic spectrum of lymphomatoid papulosis: study of 31 cases.

Herein we review the Mayo Clinic experience with thirty-one cases of lymphomatoid papulosis seen since 1965. All patients had chronic, recurrent, and self-healing erythematous papulonodular lesions, which often became pustular, ulcerated, and resolved with scarring. The clinical features often corresponded to those seen in Mucha-Habermann disease; however, the predominant histopathologic feature was an infiltrate composed primarily of atypical lymphoid cells suggestive of malignant lymphoma. In six patients, a lymphoproliferative disorder was eventually diagnosed. There were two cases of mycosis fungoides (stage I), one case of nodular sclerosing Hodgkin's disease, and three cases of malignant lymphoma--one diffuse mixed large and small cell type with features of T-immunoblastic type, one diffuse large cell type, and one follicular small cleaved cell type. The clinical course of the lymphomatoid papulosis was unaffected by chemotherapy for the lymphoproliferative disorder. Our data indicate that, with sufficient duration of follow-up, malignant lymphoma may develop in some patients with lymphomatoid papulosis.

The clinical and histopathologic spectrums of urticarial vasculitis: study of forty cases.

Urticarial skin lesions may occur in patients as a manifestation of necrotizing vasculitis. We describe a series of forty patients with idiopathic chronic urticaria and histologic features of necrotizing vasculitis. On the basis of clinical evaluation, we have classified urticarial vasculitis into two major groups: (1) hypocomplementemic (sixteen patients, ten of whom had evidence of renal disease) and (2) normocomplementemic (twelve patients with systemic disease and twelve with only cutaneous involvement). Most patients with hypocomplementemia presented with arthritis, and some had abdominal pain or airway compromise. Although patients with normocomplementemia and systemic disease had a less severe clinical course, four exhibited renal disease that was characterized by microhematuria and proteinuria. Direct immunofluorescence microscopy of the skin aids in assessing renal involvement in some cases of hypocomplementemic urticarial vasculitis, particularly when IgG and IgM are deposited at the basement membrane. There seems to be a spectrum of disease in urticarial vasculitis, ranging from benign cutaneous lesions to systemic disease.

Epidermoid hidradenoma. A clinicopathologic study.

Clinical and histopathologic data in 8 cases of epidermoid hidradenoma are presented. Most of the tumors were in the head and neck, and most of the patients were middle-aged and older adults. Generally, the lesions were asymptomatic nodules that sometimes showed ulceration or rapid growth. Despite having some histologic atypia or focal mitotic activity, the tumors were found to be benign on long-term evaluation. This epidermoid variant should not be otherwise differentiated from the benign group of solid-cystic hydradenomas, because cytologic variability did not predict a significant change in prognosis.

Basal cell tumor with eccrine differentiation (eccrine epithelioma).

In 1969, Freeman and Winkelmann reported two cases of basal cell tumors with features of eccrine differentiation. On the basis of subsequent personal cases and isolated literature reports, we wish to emphasize the characteristics of this tumor. It is an infiltrating basaloid growth, usually on the scalp or head, that frequently recurs, apparently because of inadequate excision. Basaloid, alveolar, and cystic epithelial masses, which constitute the tumor, may be seen individually or together. Areas that appear to be morpheaform epithelioma or similar to syringoma can be observed. Enzyme studies reveal phosphorylase and focal lysosomal enzymes such as acid phosphatase. Acid mucopolysaccharides are present in foci. Electron microscopy shows epithelial masses with eccrine duct features. Eccrine epithelioma is a rare tumor that may be mistaken for syringoma, basal cell carcinoma, adenocystic carcinoma, sweat gland carcinoma, or metastatic tumor. Its differentiation toward eccrine structure and function predicts the chronic, recurrent, locally infiltrative clinical course observed in patients to date.

Reactive and neoplastic epithelial alterations of the vulva. A classification of the vulvar dystrophies from the dermatopathologist's viewpoint.

The clinical classification of the vulvar dystrophies has traditionally been difficult because most of these lesions present as a white hyperkeratotic patch. An international committee for the study of the vulva designed a histologic classification that consists of: I, hyperplastic type, with or without atypia; II, lichen sclerosus; and, III, mixed dystrophy, with or without atypia. A new classification and a fourth type are proposed by us to sort out a group of strictly benign dermatoses with distinctive histopathologic features which can present clinically as a white patch in the vulva; these are best designated as benign dermatoses. In addition to these, squamous cell carcinoma in situ and Paget's disease may also be manifested as a white patch. Hence, a classification of vulvar diseases with new nomenclature is presented from the dermatopathologist's perspective, based on histologic and clinical features.

Adenoma sebaceum of Pringle: a clinicopathologic review, with a discussion of related pathologic entities.

"Adenoma sebaceum of Pringle" (ASP) is a misnomer. The tumor is not an adenoma and is not derived from sebaceous glands. The lesion is characterized by dermal fibrosis and associated vascular proliferation and dilatation. Changes in contiguous sebaceous glands and other adnexal structures are merely secondary. Thus, "angiofibroma" would be a more appropriate name. The histologic changes in ASP (and in related pathologic lesions) suggest that it is a hamartoma rather than a true neoplasm. However, the embryologic tissue of its origin is not definitively known.

The histopathology of lupus erythematosus panniculitis.

Lupus erythematosus panniculitis is a clinical variant of lupus erythematosus in which the main pathologic process involves the deep corium and subcutaneous tissue. We reviewed twenty-nine cases of lupus panniculitis, as well as the cases previously reported in the literature. The histopathologic changes in lupus panniculitis are characterized by a lymphocytic panniculitis, hyaline degeneration of the fat, hyaline papillary bodies, and lymphoid nodular structures in the lower dermis and subcutaneous tissue. Direct immunofluorescence can be important in supplementing the histopathologic study of lupus panniculitis. Lesions of discoid lupus erythematosus are seen in 21% of cases. When this disorder exists in the absence of other typical cutaneous or systemic lesions, the diagnosis of lupus erythematosus has been questioned. We believe that the histopathologic findings of this entity are alone sufficient for a diagnosis of lupus panniculitis, even in the absence of cutaneous or systemic lesions.

Melasma: a clinical, light microscopic, ultrastructural, and immunofluorescence study.

Melasma is an acquired brown hypermelanosis of the face. Although it is thought that melasma is associated with multiple etiologic factors (pregnancy, gastric, racial, and endocrine), one of the primary causes of its exacerbation appears to be exposure to sunlight. Three patterns of melasma are recognized clinically: (1) a centrofacial pattern, (2) a malar pattern, and (3) a mandibular pattern. Examination of patients with Wood's light (320--400 nm) is useful in classifying the specific type of melasma in correlation with the localization of pigment granules (melanosomes) in the epidermis and dermis. Four types of melasma are described on the basis of Wood's light examination: (1) an epidermal type, (2) a dermal type, (3) a mixed type, and (4) a fourth type, described in patients of dark complexion, in which the lesions, for lack of contrast, are not discernible on Wood's light examination, perhaps due to the increased number of melanosomes in the normal skin of black individuals. Light, histochemical, and electron microscopic studies revealed an increase in number and activity of type-specific melanocytes which appeared to be engaged in increased formation, melanization, and transfer of pigment granules (melanosomes) to the epidermis as well as to the dermis. The melanocyte seems to undergo a functional alteration brought about by a combination of multiple factors, including persistent sun exposure, hormonal factors, and genetic predisposition.

Encephalocraniocutaneous lipomatosis: a new neurocutaneous syndrome.

Encephalocraniocutaneous lipomatosis is a congenital neurocutaneous disorder with the distinguishing histopathological features of dysgenesis and neoplasia of the adipose tissue. The dominant clinical features of the syndrome include convulsions beginning in infancy, mental retardation, and unilateral cutaneous and ophthalmological lesions with ipsilateral cerebral malformations. A patient with this rare disorder of ectomesodermal dysgenesis has been studied in order to classify clinically and histologically the associated skin lesions. To our knowledge, this is the fourth case of encephalocraniocutaneous lipomatosis reported in the English literature.