Development and applications of a concentrating membrane osmometer for colloid solutions.

The membrane concentration osmometer coupled with multiple sample preparations has been used for over a century to determine a number of colloidal properties. At the dilute region, this method has been used to determine solute molecular mass. When the solution is proteinaceous, in the intermediate region, the osmotic pressure profile provides the second virial coefficient, useful for estimating protein crystallization and salting out. At the most crowded concentrations, it provides insight into protein hydration and protein-ion interaction. One of the most critical factors in generating the osmotic pressure profile is minimizing the quantity of protein used and reducing the error in preparing samples. Here, we introduce a membrane concentrating osmometer that allows one to measure osmotic pressure over a wide concentration range from a single sample. A test study was performed using the osmotic pressure profile of self-crowded bovine serum albumin solutions. The resulting profile was in good agreement with previous data in the literature obtained from multiple sample studies. The osmotic pressure profile was further used with a free solvent-based osmotic pressure model to determine protein hydration and ion binding. These results were in excellent agreement with literature values. This concentrating osmometer has several advantages over a conventional concentration osmometer for obtaining the osmotic pressure profile for proteinaceous solutions: (1) the amount of protein required is significantly decreased, (2) the potential for experimental error in sample preparation diminishes, and (3) the time for generating the osmotic pressure profile is substantially reduced.

Interrogating the Osmotic Pressure of Self-Crowded Bovine Serum Albumin Solutions: Implications of Specific Monovalent Anion Effects Relative to the Hofmeister Series.

The free-solvent-based (FSB) model and osmotic pressure were used to probe the ion binding and protein hydration for self-crowded bovine serum albumin in 0.15 M NaF, NaCl, NaI, and NaSCN solutions. All experiments were conducted with solutions at pH 7.4. The regressed results of the FSB model behavior to the measured osmotic pressure were excellent, albeit, the osmotic pressure data for NaSCN were noisy. The resulting ion binding and hydration were realistic values and the covariance of the two parameters was exceptionally low, providing substantial credibility to the FSB model. The results showed that the kosmotropic F- and neutral Cl- solutions generated significantly higher ion binding and protein hydration than the chaotropic solutions of I- and SCN-. Further, the ionic strength ratio and resulting hydration implied that the chaotropic solutions had substantially higher aggregation than the other salts investigated. Overall, the FSB model provides an additional, complementary tool to contribute to the analysis of crowded protein solutions relative to anions in the Hofmeister series as it can interrogate crowded solutions directly; something that is not possible with many measurement techniques.

Epithelium-Derived Wnt Ligands Are Essential for Maintenance of Underlying Digit Bone.

Clinically, many nail disorders accompany bone deformities, but whether the two defects are causally related is under debate. To investigate the potential interactions between the two tissue types, we analyzed epithelial-specific ß-catenin-deficient mice, in which nail differentiation is abrogated. These mice showed regression of not only the nail plate but also of the underlying digit bone. Characterization of these bone defects revealed active bone resorption, which is suppressed by Wnt activation in osteoblast and osteoclast precursors. Furthermore, we found that Wntless expression, essential for Wnt ligand secretion, was lacking in the ß-catenin-deficient nail epithelium and that genetic deletion of Wntless (Wls) in the nail epithelium led to the lack of Wnt activation in osteoblast and osteoclast precursors and subsequently led to defective regression of the underlying digit bone. Together, these data show that epithelial Wnt ligands can ultimately regulate Wnt signaling in osteoblast and osteoclast precursors, known to regulate bone homeostasis. These results reveal a critical role for the nail epithelium on the digit bone during homeostatic regeneration and show that Wnt/ß-catenin signaling is critical for this interaction.

Indeterminate cell histiocytosis that presented clinically as benign cephalic histiocytosis.

Indeterminate cell histiocytosis (ICH) is a rare, heterogeneous disorder that is characterized by immunophenotypic features of both Langerhans cell histiocytosis (LCH) and non-LCH. We describe a 12-month-old boy with a four-month history of asymptomatic, small, pink-tan papules on his face. Histopathologic evaluation showed a superficial, dermal infiltrate of histiocytes that was positive for S100, CD1a, CD68, and Factor XIIIa. To our knowledge, this represents the first report of the clinical presentation of benign cephalic histiocytosis with immunohistochemical findings of ICH. We review the classification of histiocytic disorders and the clinical and immunohistochemical features of both ICH and benign cephalic histiocytosis.

New world cutaneous leishmaniasis.

A 24-year-old Bangladeshi man presented with a 12-week history of a pruritic papule on his left elbow that had enlarged and ulcerated. He was without any constitutional or systemic symptoms. He reported a history of extensive travel in the two years prior to presentation that included Bangladesh, South and Central America, and Mexico. Histopathologic features were consistent with leishmaniasis. Speciation by the Centers for Disease Control showed L. brasiliensis.

Plate-like osteoma cutis.

Osteoma cutis is the aberrant development of bone within the skin. The bone formation may be de novo (primary) or result from an injury to the skin (secondary). Here we present a healthy 53-year-old man with no known abnormalities in calcium or phosphate metabolism with plate-like osteoma cutis of the scalp. Plate- or plaque-like osteoma cutis was initially described as a congenital condition but has now been reported several times in the literature as an idiopathic process that occurs in adults. Treatment options are limited and are only required if the lesion is bothersome to the patient.

Exogenous ochronosis.

We present a case of exogenous ochronosis in a 53-year-old woman with skin type IV, who used a topical hydroquinone preparation of an unknown concentration for several years. Traditionally, exogenous ochronosis was thought to occur exclusively in patients with darker skin types who use high concentrations of hydroquinone cream. Reports now document cases in patients of all skin types and in patients even using low concentrations of hydroquinone cream for short periods of time. Although the incidence of exogenous ochronosis in the United States is unclear, it may be more common than many clinicians believe. It is important for clinicians and patients to be aware of exogenous ochronosis in order to prevent exacerbation in patients with this rare side effect.

Netherton syndrome with ichthyosis linearis circumflexa and trichorrhexis invaginatum.

Netherton syndrome is a rare, autosomal recessive disorder that is characterized by congenital ichthyosis, trichorrhexis invaginata, and atopic diathesis. Ichthyosis presents at birth with erythroderma and subsequently evolves into ichthyosis linearis circumflexa; hair shaft abnormalities tend to present later. The disorder is caused by loss-of-function mutations in the SPINK5 (serine protease inhibitor Kazal-type 5) gene that encodes LEKTI (lympho-epithelial Kazal-type related inhibitor), which is a protease inhibitor that counteracts epidermal proteases involved in desquamation. Use of topical medications is limited by potential for systemic absorption and toxicity in the setting of a defective skin barrier. Therapeutic options include topical glucocorticoids and retinoids, oral retinoids, and narrowband ultraviolet B phototherapy. Topical tacrolimus has been shown to be efficacious and may be used safely with careful laboratory monitoring.

Nevus lipomatosus superficialis.

Nevus lipomatosus superficialis is an uncommon cutaneous hamartoma that is characterized by the presence of adipose tissue within the reticular dermis. We describe a 15-year-old boy with a three-year history of the classic type of nevus lipomatosus superficialis, which presented as linear arrays of soft, cerebriform papulonodules and plaques in the right inguinal fold. Investigation for chromosomal aberrations and dysregulation of Wnt signaling may provide insights into the pathogenesis of this hamartoma. Treatment is usually with surgical excision although successful use of other modalities has been described.

Vegetative pyoderma gangrenosum.

Vegetative pyoderma gangrenosum is a rare, superficial variant of pyoderma gangrenosum that is more commonly found on the trunk as single or multiple, non-painful lesions. There is typically no associated underlying systemic disease. Compared to classic pyoderma gangrenosum, vegetative lesions are more likely to heal without the use of systemic glucocorticoids, although up to 39% of patients required a short course of prednisone in a review of 46 cases. Treatments for vegetative pyoderma gangrenosum include topical and intralesional glucocorticoids, minocycline or doxycycline, dapsone, colchicine, and, rarely, alternative steroid-sparing immunosuppressants. We present a case of multiple vegetative pyoderma gangrenosum lesions arising in prior surgical sites in a patient found to have IgA monoclonal gammopathy and abnormal urinary protein electrophoresis.

Nail lichen planus in a patient with alopecia totalis.

A 67-year-old man with a three-year history of non-scarring alopecia that progressed to alopecia totalis despite intralesional glucocorticoid injections is presented. He developed 20-nail dystrophy that was recalcitrant to antifungal and anti-inflammatory treatments. Biopsy of the nail matrix showed histopathologic features of lichen planus. Alopecia totalis and isolated lichen planus of the nails are uncommon subtypes of common dermatologic disorders. Rarely reported concurrently, we provide a review of the literature of their association, which is most likely attributed to their autoimmune pathogeneses.

Palmoplantar lichen planus.

Palmoplantar lichen planus (PPLP) is an uncommon variant of lichen planus that affects the palms and soles. Clinical findings are varied although they have been conceptualized into two large groupings, an erythematous scaly pattern and a hyperkeratotic pattern. Histopathologic features are those of classic LP. We present a case of PPLP that improved with methotrexate after failing treatment with acitretin.

Dermatitis herpetiformis.

Dermatitis herpetiformis (DH) is an autoimmune bullous disease, which represents the cutaneous manifestation of gluten sensitivity, in the setting of celiac disease. Although classical DH is characterized clinically by grouped, vesicles on an erythematous base, primary lesions often are absent owing to the intense, associated pruritus. Instead, many cases present only with erythematous erosions with numerous overlying excoriations. As in celiac disease, the core pathogenic mechanisms of DH are likely mediated by immunoglobulin A class autoantibodies against one of several transglutaminase enzymes. As the production of these autoantibodies is directly correlated with gastrointestinal exposure to gliadin, which is an alcohol-soluble fraction of gluten, a gluten-free diet represents the cornerstone of a DH management regimen. In cases refractory to dietary management alone, dapsone is the first-line agent for the treatment of DH, although many other agents have been anecdotally reported as effective.

Pemphigus foliaceus.

A 55-year-old woman presented after a four-year history of impetiginized eczema that was distributed over her face, scalp, chest, and back and a recent diagnosis of breast cancer. A skin biopsy specimen for direct immunofluorescence demonstrated intercellular IgG4. Anti-desmoglein 1 and 3 antibodies were present. Indirect immunofluorescence testing was positive on monkey but not rat esophagus. These findings were consistent with a diagnosis of pemphigus foliaceus in association with a malignant condition. After many years of the use of topical glucocorticoids and oral antibiotics, the patient's disease was ultimately managed with methotrexate and a small dose of prednisone. Increasing data supports a role for a steroid-sparing effect of methotrexate in pemphigus vulgaris and likely pemphigus foliaceus.

Collision tumor of eccrine poroma, seborrheic keratosis, and a viral wart.

A 68-year-old woman presented for evaluation of a large, red-brown plaque on her left buttock with irregular borders and prominent overlying verrucous changes. The plaque had been present since childhood but over a three-year period had been enlarging with increasing nodularity and easy bleeding with trauma. Histopathologic examination demonstrated an enlarged papillated and polypoid heterogeneous lesion. In part of the specimen, there are bulbous aggregates of small squamous cells with foci of eccrine ductal differentiation. There are other areas with horn pseudocysts, hypergranulosis, and compact orthokeratosis with parakeratosis. There are scattered enlarged heavily pigmented melanocytes, some of which have long and thick dendrites. This collision tumor consisted of an eccrine poroma, a seborrheic keratosis, and a viral wart. The clinical and histopathologic features of collision tumors and poromas are reviewed.

Adiposis dolorosa.

We report a 46-year-old woman with a nine-year history of obesity; chronic diffuse pain in the adipose tissue of her medial upper arms, lower trunk, and thighs; multiple biopsy-proven lipomas and angiolipomas; and a lipomatous pseudomass of the breast. Her systemic symptoms included generalized weakness, fatigue, memory impairment, and arthralgias. Although some of the lesions were tender, most were only appreciated with palpation. Her clinical history and histopathologic data suggested adiposis dolorosa (Dercum's disease). Owing to the chronic pain, an interdisciplinary approach with the use of analgesics and doxycycline has been initiated.

Vulvar nevi, melanosis, and melanoma: an epidemiologic, clinical, and histopathologic review.

Pigmented vulvar lesions are present in approximately 1 in 10 women and include melanocytic and nonmelanocytic proliferations. Vulvar nevi, melanosis, and melanoma are particularly challenging because of the similarity of their clinical and/or histopathological presentation. As a result, they are often difficult to diagnose, may result in patient and physician anxiety, and can lead to unneeded, potentially disfiguring surgical procedures. Because it is often detected late, vulvar melanoma carries a poor prognosis with associated significant morbidity and mortality, underscoring the importance of prompt recognition and treatment. In this review, we analyze the distinct epidemiologic, clinical, and histopathologic characteristics of vulvar nevi, melanosis, and melanoma, discuss treatment options, and propose a practical, systematic approach to facilitate formulation of a differential diagnosis and initiation of appropriate management.

Urethral adenocarcinoma associated with intestinal-type metaplasia, case report and literature review.

The presence of glandular epithelium in urinary tract biopsies poses a diagnostic challenge. Intestinal metaplasia of the urethra may be seen in many congenital, iatrogenic, and reactive conditions, as well as in association with malignant conditions such as urethral adenocarcinoma. We present a case of a 61 year-old woman presenting with microscopic hematuria. Successive biopsies showed glandular epithelium with focal atypia in close association with inflammation, but no overt malignancy. Only on surgical resection was the associated high grade adenocarcinoma revealed. When intestinal-type mucosa is present within a urinary tract biopsy, associated malignancy may be present only focally. Thorough sampling and consideration of the differential diagnosis is imperative.

Mitotic rate in melanoma: prognostic value of immunostaining and computer-assisted image analysis.

The prognostic value of mitotic rate in melanoma is increasingly recognized, particularly in thin melanoma in which the presence or absence of a single mitosis/mm can change staging from T1a to T1b. Still, accurate mitotic rate calculation (mitoses/mm) on hematoxylin and eosin (H&E)-stained sections can be challenging. Antimonoclonal mitotic protein-2 (MPM-2) and antiphosphohistone-H3 (PHH3) are 2 antibodies reported to be more mitosis-specific than other markers of proliferation such as Ki-67. We used light microscopy and computer-assisted image analysis software to quantify MPM-2 and PHH3 staining in melanoma. We then compared mitotic rates by each method with conventional H&E-based mitotic rate for correlation with clinical outcomes. Our study included primary tissues from 190 nonconsecutive cutaneous melanoma patients who were prospectively enrolled at New York University Langone Medical Center with information on age, gender, and primary tumor characteristics. The mitotic rate was quantified manually by light microscopy of corresponding H&E-stained, MPM-2-stained, and PHH3-stained sections. Computer-assisted image analysis was then used to quantify immunolabeled mitoses on the previously examined PHH3 and MPM-2 slides. We then analyzed the association between mitotic rate and both progression-free and melanoma-specific survival. Univariate analysis of PHH3 found significant correlation between increased PHH3 mitotic rate and decreased progression-free survival (P=0.04). Computer-assisted image analysis enhanced the correlation of PHH3 mitotic rate with progression-free survival (P=0.02). Regardless of the detection method, neither MPM-2 nor PHH3 offered significant advantage over conventional H&E determination of mitotic rate.