Alopecia Areata in C3H/HeJ Mice Involves Leukocyte-mediated Root Sheath Disruption in Advance of Overt Hair Loss

Alopecia areata (AA) can be induced in C3H/HeJ mice by grafting full-thickness AA-affected skin. An 8- to 12-week delay between surgery and overt hair loss onset provides an opportunity to examine disease pathogenesis. Normal haired C3H/HeJ mice were sham-grafted or grafted with AA-affected skin. Mice were euthanatized 2, 4, 6, 8, 10, and 12 weeks after surgery along with chronic AA-affected mice as a positive control. Until 6 weeks after grafting, inflammation was only evident around anagen-stage hair follicles in host skin adjacent to but not distant from the AA-affected graft. From 8 weeks on, AA-grafted but not sham-grafted mice exhibited a diffuse dermal inflammation at distant sites that progressively focused on anagen-stage hair follicles at 10 and 12 weeks. Perifollicular inflammation was primarily composed of CD4+ and CD8+ cells associated with follicular epithelium intercellular adhesion molecule -1 expression. Only CD8+ cells penetrated intrafollicularly by 12 weeks after surgery, although both CD4+ and CD8+ intrafollicular cells were observed in chronic AA-affected mice. Under electron microscopy, intrafollicular lymphocyte and macrophage infiltration associated with hair follicle dystrophy was prominent 10 weeks after surgery, primarily within the differentiating outer and inner root sheaths. This study shows that focal follicular inflammation develops some time in advance of overt hair loss and focuses on the differentiating root sheaths in C3H/HeJ mice. The severity of inflammation and the degree of hair follicle dystrophy induced by the infiltrate appear to reach a threshold level before overt hair loss occurs.

Bioaccumulation of pharmaceuticals and personal care products in the unionid mussel Lasmigona costata in a river receiving wastewater effluent

Freshwater mussels are frequently found in rivers receiving effluent from wastewater treatment plants (WWTP), and there is strong evidence that poor water quality is deleterious to freshwater mussel populations. WWTPs are among the main sources of pharmaceuticals and personal care products (PPCPs) in surface waters. We monitored 145 PPCPs in wild and caged mussels both upstream and downstream of the Kitchener WWTP in the Grand River, Ontario, as well as 118 PPCPs in water samples. Our objectives were to characterize the seasonal changes in PPCP concentrations in water, to calculate bioaccumulation factors (BAFs) of PPCPs in mussels, and to determine the chemical and physical properties of PPCPs driving the bioaccumulation. Seventy PPCPs were detected in water, and concentrations were highest in the summer or early fall, which corresponded to low river flow. Forty-three PPCPs from many pharmaceutical classes were detected in mussel tissues, including stimulants, a contrasting agent, anti-inflammatory drugs, anti-bacterial agents, antibiotics, antidepressants, antihistamines, progestins, and illicit drugs such as cocaine and amphetamines. The BAFs ranged from 0.66 for metformin to 32,022 for sertraline. Using partial least squares to predict BAFs based upon chemical properties, log KOC, Log KOW, and fugacity ratio (sediment) all had similar and positive loadings with BAFs (R(2)X = 0.70; caged mussels). BAFs of PPCPs in mussels were predictable from fugacity models that estimate bioconcentration factors using log KOW. Our study demonstrated that mussels readily bioaccumulate PPCPs, in a manner consistent with expectations based upon BCF models and the chemical characteristics of each compound.

Microsatellite DNA mutations in double-crested cormorants (Phalacrocorax auritus) associated with exposure to PAH-containing industrial air pollution

Hamilton Harbour, Ontario, Canada is one of the most polluted sites on the Great Lakes, and is subject to substantial airborne pollution due to emissions from both heavy industry and intense vehicle traffic. Mutagenic Polycyclic aromatic hydrocarbons (PAHs) are present at very high concentrations in the air and sediment of Hamilton Harbour. We used five variable DNA microsatellites to screen for mutations in 97 families of Double-crested Cormorants (Phalacrocorax auritus) from three wild colonies, two in Hamilton Harbour and one in cleaner northeastern Lake Erie. Mutations were identified in all five microsatellites at low frequencies, with the majority of mutations found in chicks from the Hamilton Harbour site closest to industrial sources of PAH contamination. Microsatellite mutation rates were 6-fold higher at the Hamilton Harbour site closest to the industrial sources of PAH contamination than the other Hamilton Harbour site, and both were higher than the reference colony. A Phase I metabolite of the PAH benzo[a]pyrene identified by LC-MS/MS in bile and liver from Hamilton Harbour cormorant chicks suggests that these cormorants are exposed to and metabolizing PAHs, highlighting their potential to have caused the observed mutations.

Development of a calibration methodology for large-volume, solid ⁶⁸Ge phantoms for traceable measurements in positron emission tomography

We have developed a methodology to calibrate the (68)Ge activity concentration in large (9L) cylindrical epoxy phantoms in a way that is traceable to national standards. The method was tested on two prototype cylindrical phantoms that are being used in a clinical trial and gave (68)Ge activity concentration values with combined standard uncertainties of about 1.1%. Imaging data from the phantoms using a calibrated PET-CT scanner gave values consistent with the calibrated activity concentrations within experimental uncertainties.

Calibration of Traceable Solid Mock (131)I Phantoms Used in an International SPECT Image Quantification Comparison

The International Atomic Energy Agency (IAEA) has organized an international comparison to assess Single Photon Emission Computed Tomography (SPECT) image quantification capabilities in 12 countries. Iodine-131 was chosen as the radionuclide for the comparison because of its wide use around the world, but for logistical reasons solid (133)Ba sources were used as a long-lived surrogate for (131)I. For this study, we designed a set of solid cylindrical sources so that each site could have a set of phantoms (having nominal volumes of 2 mL, 4 mL, 6 mL, and 23 mL) with traceable activity calibrations so that the results could be properly compared. We also developed a technique using two different detection methods for individually calibrating the sources for (133)Ba activity based on a National standard. This methodology allows for the activity calibration of each (133)Ba source with a standard uncertainty on the activity of 1.4 % for the high-level 2-, 4-, and 6-mL sources and 1.7 % for the lower-level 23 mL cylinders. This level of uncertainty allows for these sources to be used for the intended comparison exercise, as well as in other SPECT image quantification studies.

Feasibility study on the spatial and temporal movement of Samburu's cattle and wildlife in Kenya using GPS radio-tracking, remote sensing and GIS

The study was conducted to assess the technical feasibility of studying the spatial and temporal interaction of traditionally herded livestock and wildlife using global positioning system (GPS) tracking technology in Northern Kenya. Two types of collars were used on nine cows: radio frequency and global system for mobile communications (GSM) collars and GPS-satellite (SAT) collars. Full results of cattle tracking were available for eight cows (3 GSM and 5 SAT) tracked between July 2008 and September 2010. A cumulative total of 1556 tracking days was recorded over the 17 month period. On average cows walked 10,203 m/day (average total monthly distance walked was 234 km). Significant seasonal differences were found; on average cows walked 9.607 m and 10,392 m per day in the rainy and the dry seasons, respectively. This difference was also significant for total monthly and daily distance walked between the dry and the rainy season. On average cows walked daily 9607 m and 10,392 m on the rainy and the dry season respectively. During the dry months a 48 h cycle was observed with cows walking 15-25 km to water every 2nd day but only 5-8 km/day between watering days. There was a 24% overlap of cattle range with both elephants and zebras. This study demonstrated the feasibility of tracking cattle using radio collars. It shows the complexity of spatial use by cattle and wildlife. Such information can be used to understand the dynamics of disease transmission between livestock and wildlife.

Primary follicular dystrophy with scarring dermatitis in C57BL/6 mouse substrains resembles central centrifugal cicatricial alopecia in humans

A number of C57BL/6 (B6) substrains are commonly used by scientists for basic biomedical research. One of several B6 strain-specific background diseases is focal alopecia that may resolve or progress to severe, ulcerative dermatitis. Clinical and progressive histologic changes of skin disease commonly observed in C57BL/6J and preliminary studies in other closely related substrains are presented. Lesions develop due to a primary follicular dystrophy with rupture of severely affected follicles leading to formation of secondary foreign body granulomas (trichogranulomas) in affected B6 substrains of mice. Histologically, these changes resemble the human disease called central centrifugal cicatrical alopecia (CCCA). Four B6 substrains tested have a polymorphism in alcohol dehydrogenase 4 (Adh4) that reduces its activity and potentially affects removal of excess retinol. Using immunohistochemistry, differential expression of epithelial retinol dehydrogenase (DHRS9) was detected, which may partially explain anecdotal reports of frequency differences between B6 substrains. The combination of these 2 defects has the potential to make high dietary vitamin A levels toxic in some B6 substrains while not affecting most other commonly used inbred strains.

A new large-area 2pi proportional counting system at NIST

A new large-area gas flow multi-wire proportional counter has been developed to replace the large-area counting system that is currently in use at the National Institute of Standards and Technology (NIST) and several Department of Defense counting facilities for calibrating large-area alpha and beta sources. The current systems are over 20 years old and part replacement is very difficult. The new systems have been built using specifications that will improve on the current systems and allow collecting data at pressures up to 0.2MPa. The ability to operate at higher pressures will increase the beta efficiency of the counter and lead to improved precision in the final measured results. Comparison of the results from the old and new systems is presented for both alpha and beta sources.

Epidermal growth factor/transforming growth factor alpha receptors and psoriasis

The abnormal growth and differentiation in psoriasis is reflected in the abnormal regulation of Epidermal Growth Factor/Transforming Growth Factor Alpha (EGF/TGFalpha) receptor metabolism. In psoriasis and other hyperproliferative skin conditions these receptors are persistently expressed throughout the interfollicular epidermis as long as the growth stimulatory signal persists. One of the first biochemical signs of effective therapy of psoriasis is the return of the EGF/TGFalpha receptor pattern toward the primarily basilar distribution seen in normal human adult skin. Whether the abnormal expression of TGFalpha in the involved skin induces the persistent expression of EGF receptors is not known nor is the signal that causes the increased production of TGFalpha. Studies to determine what factors regulate EGF receptor expression and TGFalpha induction may yield important new insights into the pathogenesis and therapy of psoriasis.

Reactive site-dependent phenotypic alterations in plasminogen activator inhibitor-1 transgenic mice

BACKGROUND

Plasminogen activator inhibitor-1 (PAI-1) is the major physiological inhibitor of plasminogen activators (PAs) and plays a role in the regulation of a number of physiological processes including the degradation of extracellular matrix proteins, cell proliferation and migration, and intracellular signaling.

AIM

To characterize the effects of durable expression of a stable form of human PAI-1 and to characterize important structure-function relationships in PAI-1 in vivo.

METHODS

We developed transgenic mice lines overexpressing stable variants of human PAI-1 under the control of the murine preproendothelin-1 promoter and characterized the phenotypic alterations displayed by transgenic mice.

RESULTS

Transgenic mice expressing an active form of human PAI-1 (PAI-1-stab) display complex phenotypic abnormalities including alopecia and hepatosplenomegaly. Reactive site mutant transgenic mice expressing inactive PAI-1 exhibit complete phenotypic rescue, while transgenic mice expressing PAI-1 with reduced affinity for vitronectin manifest all of the phenotypic abnormalities present in PAI-1-stab transgenic mice.

CONCLUSIONS

The protease inhibitory activity of PAI-1 toward PAs and/or other serine proteases is necessary and sufficient to promote complex phenotypic abnormalities and mediates many of the physiological effects of PAI-1 in vivo.

Radiographic joint damage in rheumatoid arthritis is associated with differences in cartilage turnover and can be predicted by serum biomarkers: an evaluation from 1 to 4 years after diagnosis

INTRODUCTION

The objective of this study was to determine whether serum biomarkers for degradation and synthesis of the extracellular matrix of cartilage are associated with, and can predict, radiographic damage in patients with rheumatoid arthritis (RA).

METHODS

Clinical and radiographic data of 87 RA patients were recorded 1 year after disease onset and then annually up to four years. Serum concentrations of four cartilage biomarkers were determined at these time points: a neoepitope formed by collagenase cleavage of type II collagen (C2C), a neoepitope formed by collagenase cleavage of type II collagen as well as type I collagen (C1,2C), a carboxy propeptide of type II procollagen formed during synthesis (CPII), and a cartilage proteoglycan aggrecan turnover epitope (CS846-epitope). Biomarker concentrations between patients with rapid radiographic progression (>7.3 Sharp/van der Heijde units per year) and those with slow radiographic progression (<2.3 units per year) were compared. In addition, we evaluated the long-term and short-term predictive value of each biomarker for progression of radiographic damage.

RESULTS

Patients with rapid radiographic progression had higher C2C, higher C1,2C, and higher CS846-epitope levels than slow progressors. CPII levels showed no differences. Most importantly, the long-term radiographic progression for C2C, for C1,2C, and for CS846-epitope can be predicted by the biomarker value at year 1 after disease onset. C2C was also a predictor for joint space narrowing and annual radiographic damage during the subsequent year.

CONCLUSION

This study shows that the concentration of serum biomarkers of cartilage collagen breakdown and proteoglycan turnover, but not of collagen synthesis, are related to joint destruction in RA. The use of these biomarkers may be of value when studying progression of joint damage in patients with RA.

Detection of aggrecanase- and MMP-generated catabolic neoepitopes in the rat iodoacetate model of cartilage degeneration

OBJECTIVE

To characterize the time course of aggrecan and type II collagen degradation in the rat iodoacetate model of cartilage degeneration in relationship to the temporal sequence that has been described in human osteoarthritis (OA).

DESIGN

Rats were injected intra-articularly in one knee joint with iodoacetate and damage to the tibial plateau was assessed from digitized images captured using an image analyzer. The articular cartilage from the tibial plateau was harvested, extracted and glycosaminoglycan (GAG) content was measured using the dimethylmethylene blue (DMMB) assay. Cartilage aggrecan neoepitopes were detected in cartilage extracts by Western blotting using antibodies recognizing the aggrecanase-generated C-terminal neoepitope NITEGE (BC-13) and the MMP-generated C-terminal neoepitope DIPEN (BC-4). A type II collagen collagenase-generated neoepitope was detected in cartilage extracts by ELISA using the Col2-3/4Cshort antibody; denatured collagen was detected using the Col2-3/4m antibody.

RESULTS

Degenerative joint changes and proteoglycan (GAG) loss progressed with time after iodoacetate injection. Western blotting of cartilage extracts of iodoacetate treated rats demonstrated an increase in both aggrecanase- and MMP-generated epitopes with the NITEGE aggrecanase neoepitope being significantly elevated on days 7, 14 and 21 while DIPEN the MMP neoepitope was significantly elevated on days 7 and 14. The type II collagen neoepitope recognized by Col2-3/4Cshort was significantly increased in cartilage extracts of rats at days 14 and 21 after iodoacetate injection.

CONCLUSION

The proteoglycan fragments extracted from the knee cartilage of rats after the intra-articular injection of iodoacetate appeared to result from cleavage at both aggrecanase and MMP sites. Cleavage of type II collagen by collagenase was also detected after iodoacetate injection and occurred subsequent to the initiation of aggrecan loss. These observations serve to demonstrate similarities in the mechanisms of cartilage degeneration induced by iodoacetate to those seen in articular cartilage in OA.

Apoptosis plays a distinct role in the loss of precursor lymphocytes during zinc deficiency in mice

Lymphopenia is a characteristic of zinc deficiency, which is associated with massive loss of pre-B and pre-T cells from the primary lymphoid organs of zinc-deficient mice that have elevated serum corticosterone (CS). We examined whether this naturally elevated glucocorticoid level is associated with increased apoptotic loss of pre-T cells in the thymus of A/J and CAF1/J mice. In three experiments, partially atrophied thymuses were removed from 20 marginally zinc-deficient (ZD) young adult mice and cultured for 6 h in parallel with thymocytes prepared from 17 adequately fed mice. Thymocyte immunophenotyping combined with flow cytometric cell cycle analysis was used to identify the degree of apoptotic cell death among thymocytes of the two dietary groups, which were compared in the absence of in vivo phagocytosis. Apoptosis was enhanced 50-300% among pre-T cells (CD4+CD8+) prepared from ZD mice. This resulted in a 38% shrinkage of the thymic pre-T cell compartment, which was associated with an 80% decrease in thymic cell number. Pro-T cells (CD4-CD8-) and mature T cells (CD4+CD8-, CD4-CD8+), which express higher levels of Bcl-2 protein, survived ZD to a greater extent and formed a greater proportion of the remaining thymocyte population in ZD mice. Collectively, these data show that heightened degrees of apoptotic cell death induced in vivo by CS-disrupted thymic T cell lymphopoiesis, identifies the means of disruption of marrow B cell lymphopoiesis and explains the appearance of lymphopenia.

What is the 'true' function of skin?

Conventional textbook wisdom portrays the skin as an organ that literally enwraps whatever each of us stands for as a more or less functional, individual member of the mammalian species, and has it that the skin primarily establishes, controls and transmits contacts with the external world. In addition, the skin has long been recognized to protect the organism from deleterious environmental impacts (physical, chemical,microbiological), and is well-known as crucial for the maintenance of temperature, electrolyte and fluid balance. Now, ever more studies are being published that show the skin to also operate as a huge and highly active biofactory for the synthesis,processing and/or metabolism of an astounding range of e.g. structural proteins, glycans, lipids and signaling molecules. Increasingly, it becomes appreciated that the skin, furthermore, is an integral component of the immune, nervous and endocrine systems, with numerous lines of cross-talk between these systems established intracutaneously (e.g. Ann NY Acad Sci Vol 885, 1999; Endocrine Rev 21:457-487, 2000; Physiol Rev 80:980-1020, 2001; Exp Dermatol 10: 349-367, 2001). All these emerging cutaneous functions beyond the classical image of the skin as a barrier and sensory organ are immediately relevant for many of the quandaries that clinical dermatology, dermatopathology, and dermatopharmacology are still struggling with to-date, and offer the practising dermatologist attractive new targets for therapeutic intervention. Yet, many of these skin functions are not even mentioned in dermatology textbooks and await systematic therapeutic targeting. Following a suggestion by Enno Christophers, the current 'Controversies' feature brings together an unusually diverse council of biologists and clinicians, who share their thought-provoking views with the readers and allow us to peek into the future of research in cutaneous biology, not the least by reminding us of the -- often ignored -- evolutionary and embryonal origins of our favorite organ. Hopefully, this unique discussion feature will foster an understanding of the 'true' skin functions that is both more comprehensive and more profound than conventional teaching on this topic, and will stimulate more than 'skin-deep' reflections on the full range of skin functions.

Melanocyte and gonad activity as potential severity modifying factors in C3H/HeJ mouse alopecia areata

Circumstantial evidence has previously suggested gonad derived steroid hormones and melanogenesis related antigens may modify human alopecia areata (AA). AA-like hair loss can be induced in C3H/HeJ mice after skin allografts from spontaneous AA-affected mice. This inducible model was used to evaluate hormones and hair follicle melanocyte presence as disease-severity modifiers. Ten females and 9 males were gonadectomized and received AA-affected allografts. All gonadectomized mice had 2-4 weeks delay in AA onset relative to non-gonadectomized controls. Two females and 4 males failed to develop any AA by 25 weeks after grafting. The experiment was repeated with gonadectomized female and male mice plus non-gonadectomized mice subcutaneously implanted with silastic capsules containing 80 microg 17beta estradiol or 10 mg 5alpha dihydrotestosterone, respectively. Five of 11 ovariectomized and 9 of 11 non-ovariectomized, estradiol supplemented females developed AA with extremely rapid progression. Three of 8 castrated, but none of 11 non-castrated, dihydrotestosterone-supplemented males expressed AA. In a separate study, 14 mice were freeze-branded, producing white hair on the dorsal lumbar region, and later received full-thickness allografts. Thirteen mice developed patchy pigmented and non-pigmented hair loss. One mouse developed diffuse, pigmented hair loss, but with white hair survival persisting 25 weeks after grafting. The results suggest that gonadal steroid hormones can modulate C3H/HeJ mouse AA where estradiol promoted rapid progression of AA while dihydrotestosterone increased resistance to AA onset. In general, both pigmented and non-pigmented C3H/HeJ mouse hair is susceptible to AA. Murine AA susceptibility and severity clearly involves an interplay between genetic and epigenetic factors.

Chlamydia pneumoniae and chronic skin wounds: a focused review

The genus, Chlamydophilia, as obligate intracellular pathogens, induce chronic scarring in humans. Chlamydia pneumoniae, a common cause of pneumonia, infects endothelial cells and circulating macrophages. Evidence that C. pneumoniae is an opportunistic pathogen in chronic skin ulcers and other inflammatory skin conditions analogous to its role in atherosclerosis is reviewed.

A distinct role for apoptosis in the changes in lymphopoiesis and myelopoiesis created by deficiencies in zinc

Reduced numbers of lymphocytes in the peripheral immune system appeared to be a significant cause of the loss in host defense capacity in humans and animals that are zinc deficient (ZD). A series of studies verified that ZD substantially reduced the lymphocyte compartment of both the marrow and thymus in young adult mice, with large losses noted among the pre-B and pre-T cells. Suboptimal nutriture along with chronic production of glucocorticoids generated during ZD had accelerated apoptosis among these precursor lymphocytes two- to threefold. Thus, the primary cause of the lymphopenia created by ZD was reduced production of lymphocytes and heightened cell death among precursor cells. The data will also show that myelopoiesis in the marrow was protected and enhanced numbers of myeloid progenitor cells were found in S and G2/M. Thus, as zinc became limiting the second line of defense appeared to be down-regulated via reduction of lymphopoiesis while cells of the myeloid lineage were protected to maintain the first line of defense that provides innate immunity. This may represent an important adaptation of the immune system to suboptimal nutriture that deserves further exploration.

Amyopathic dermatomyositis

Amyopathic dermatomyositis is a variant of dermatomyositis that is characterized by the typical skin rash but without the muscle abnormalities. It has been proposed that the amyopathic and myopathic forms of dermatomyositis exist on a continuum, a concept that is supported by family and genetic studies and the observation that a small proportion of amyopathic patients transform to a frankly myopathic state. The amyopathic state is defined by a lack of muscle weakness and through diagnostic tests, including serum muscle enzymes, electromyogram studies, and muscle biopsies, that are usually normal or show only minimal abnormalities. Despite the lack of weakness, many patients complain of debilitating fatigue. More sensitive measures of muscle function, such as P-31 magnetic resonance spectroscopy, suggest that muscle metabolism is abnormal in amyopathic patients. The amyopathic form is more commonly seen in adults than in children, although juvenile cases are reported. Some early series suggested no association with underlying malignancies, but recent reports indicate that malignancies occur. Determining whether a patient has amyopathic rather than myopathic disease may have prognostic implications.

Histologic features of actinic keratoses in solid organ transplant recipients and healthy controls

BACKGROUND

Squamoproliferative lesions are common in patients who are immunosuppressed, particularly in recipients of solid organ transplants. Histologic features in such biopsy specimens may differ from those of otherwise healthy patients. Actinic keratoses (AKs) in transplant recipients may possess pathologic characteristics that suggest that they arose in an immunosuppressed host.

OBJECTIVE

We evaluated 30 randomly selected AKs from 25 recipients of solid organ transplants and compared their histologic features to those of 50 AKs from 45 patients who were not immunosuppressed.

METHODS

Tissue samples were categorized by sex, patient age, and site of biopsy. Sixteen separate histologic criteria were evaluated in a blinded fashion in each specimen. Statistical analysis was performed between the two groups with and without controlling for the age of the patient.

RESULTS

The transplant group was significantly younger (54.8 years) than the nontransplant group (70.0) and contained more men (88%) than women (51%). AKs from transplant recipients were statistically more likely to demonstrate bacterial colonization, confluent parakeratosis, hyperkeratosis, increased mitotic activity, and verrucous changes. After controlling for age only, hyperkeratosis failed to be more prevalent in the transplant group.

CONCLUSION

Certain histopathologic features are more common in AKs of immunosuppressed transplant recipients and may be used to distinguish between those removed from otherwise healthy persons.

Animal models for male pattern (androgenetic) alopecia

The stump-tailed macaque (Macaca arctoides) appears to be a suitable biological model for human androgenetic alopecia. The expense, danger, and low availability compromise its value but macaques currently remain the model of choice. Rodent models, both testosterone induced alopecia and various xenograft approaches, show promise for elucidating fundamental information on normal and abnormal hair growth as well as serving as models to develop new therapies to treat hair loss.

Morphology of hair in normal and mutant laboratory mice

Inbred laboratory mice are mammals and therefore are haired. Mice develop many of the same diseases as humans and have become the premier in vivo model for studying biology, pathology, genetics, and molecular mechanisms. Mice are useful tools to study hair biology. Examples of characterized mutant mice with abnormal pilosebaceous unit phenotypes are presented to illustrate the value of these animals as models to help understand human diseases of the skin and hair.

Nineteen documented cases of Loxosceles reclusa envenomation

OBJECTIVE

Our purpose was to review documented Loxosceles reclusa (brown recluse spider) envenomations and to describe the natural history.

METHODS

This article is a retrospective review of 19 documented cases seen in a university dermatology clinic. The study included the cases of 11 female and 8 male patients between the ages of 15 and 54 years with documented cases of brown recluse spider bite between 1987 and 1993. Rest, ice compresses, elevation, and prophylactic antibiotics were used in all cases. Fourteen patients received dapsone and 11 received nonsteroidal anti-inflammatory drugs. Two patients were hospitalized. A 3-point scale of cutaneous lesion severity was developed. Analysis of the association between maximum lesion severity (mild, moderate, severe) and time to complete healing or final evaluation was statistically significant (P < .001).

RESULTS

All patients presented with localized erythema. Most bites were on the extremities (18/19; 95%). The most common presenting symptom was pain at the bite site (10/19; 53%). Eleven patients (58%) had skin necrosis; 32% of them had areas of necrosis larger than 1 cm(2). Time to healing ranged from 5 days to more than 17 weeks (mean, 5.6 weeks). Average time to healing for grade 3 (severe) lesions was 74 days, for grade 2 (moderate) lesions 22 days, and for grade 1 (mild) lesions 8 days (in patients seen more than once).

CONCLUSIONS

Brown recluse spider bites frequently induce necrotic, slowly healing lesions. Maximum lesion severity is a predictor of time to complete healing.

Necrotic arachnidism

Necrotic arachnidism is the potential cutaneous reaction to spider bite venom. In the United States, members of 7 spider families may be responsible for envenomation sufficiently severe to warrant treatment. Characteristics of several spiders, in particular Loxosceles spiders, whose bite is toxic to humans are described, and diagnostic standards, preventive measures, and treatment options are reviewed. (J Am Acad Dermatol 2001;44:561-73.)

LEARNING OBJECTIVE

After the completion of this learning activity, participants should be familiar with the characteristics of several different spider families endemic to the United States. Furthermore, this learning activity should aid in the prevention and diagnosis of spider bites as well as in the classification and treatment of specific bites.

Middermal elastolysis in two patients with lupus erythematosus

Despite lupus erythematosus (LE) being considered a "connective tissue disease," little has been written about the elastic fiber changes in the skin of affected patients. We report our histologic findings in two patients with unusual cutaneous lesions. Elastic fiber loss was noted, and scattered giant cells with elastic fiber phagocytosis were prominent in one patient. The findings are similar to those described for middermal elastolysis. Other authors have reported patients with LE and elastic fiber loss resembling anetoderma. We believe that a spectrum of elastic fiber changes can occur in patients with LE and may be induced by infiltrating lymphocytes and/or circulating antibodies.

Comparison of alopecia areata in human and nonhuman mammalian species

Alopecia areata (AA) is a nonscarring form of inflammatory hair loss in humans. AA-like hair loss has also been observed in other species. In recent years the Dundee experimental bald rat and the C3H/HeJ mouse have been put forward as models for human AA. AA in all species presents with a wide range of clinical features from focal, locally extensive, diffuse hair loss, to near universal alopecia. Histologically, all species have dystrophic anagen stage hair follicles associated with a peri- and intrafollicular inflammatory cell infiltrate. Autoantibodies directed against anagen stage hair follicle structures are a consistent finding. Observations on AA pathogenesis suggest nonhuman species can provide excellent models for the human disease. Ultimately, animal models will be used to determine the genetic basis of AA, potential endogenous and/or environmental trigger(s), mechanism(s) of disease initiation and progression, and allow rapid evaluation of new and improved disease treatments.

Variations in the cell cycle status of lymphopoietic and myelopoietic cells created by zinc deficiency

Zinc deficiency causes thymic atrophy and lymphopenia. It was recently shown that zinc deficiency causes sizable losses among the precursor lymphocytes, such that this compartment was depleted 40%-50% in the marrow of young adult mice. However, the myeloid compartments increased substantially both in proportion and absolute number as zinc deficiency advanced. Zinc deficiency caused no change in the cell cycle status of precursor B cells and only modest changes in cycling pro-B cells. Conversely, cells of the myeloid series, especially monocytes, exhibited as much as a 40% increase in the proportion of cells in S and G(2)/M, while myeloid progenitors had an overall 56% increase in cells in the proliferative phase as zinc deficiency advanced. Whether zinc deficiency alters the rate of production of myeloid and lymphopoietic cells or alters the degree of apoptosis or both awaits further study.

Mercury exposure and cutaneous disease

Human contact with mercury has been ongoing for centuries and was previously considered a legitimate means of treating different cutaneous and systemic conditions. Toxicity from this heavy metal may occur from exposure to elemental, inorganic, and organic forms of mercury. This article outlines the signs and symptoms of mercury poisoning and the different clinical conditions with assorted cutaneous findings.

Lanceolate hair-J (lahJ): a mouse model for human hair disorders

Lanceolate hair-J (lahJ) arose spontaneously in 1994 on the DBA/1LacJ inbred background at The Jackson Laboratory. Mutant mice were runted, alopecic, and lacked vibrissae. As they aged, their skin wrinkled. Affected mice developed a noninflammatory, proliferative skin disease with follicular dystrophy. Hair fibers developed a number of abnormalities including periodic nodules along the shaft (trichorrhexis nodosa), compaction resembling trichorrhexis invaginata, spiral fractures, broken tips, and lance-shaped tips. This mutation exhibits some characteristics that resemble an autosomal recessive ichthyosiform disease that occurs in humans characterized in part by peculiar, invaginating, multinodal, hair shaft abnormalities known as Netherton's syndrome. Periodic nodules also resemble the human genetic based disease monilethrix. This autosomal recessive mouse mutation, allelic with lanceolate hair (lah), based on breeding studies, is located on mouse Chromosome 18, within a cluster of genes coding for adhesion molecules. Homozygotes for either of these allelic mouse mutations have elevated serum IgE levels, a feature also common with human Netherton's syndrome.

The dynamic link between the integrity of the immune system and zinc status

The results of more than three decades of work indicate that zinc deficiency rapidly diminishes antibody- and cell-mediated responses in both humans and animals. The moderate deficiencies in zinc noted in sickle cell anemia, renal disease, chronic gastrointestinal disorders and acrodermatitis enteropathica; subjects with human immunodeficiency virus; children with diarrhea; and elderly persons can greatly alter host defense systems, leading to increases in opportunistic infections and mortality rates. Conversely, short periods of zinc supplementation substantially improve immune defense in individuals with these diseases. Mouse models demonstrate that 30 d of suboptimal intake of zinc can lead to 30-80% losses in defense capacity. Collectively, the data clearly demonstrate that immune integrity is tightly linked to zinc status. Lymphopenia and thymic atrophy, which were the early hallmarks of zinc deficiency, are now known to be due to high losses of precursor T and B cells in the bone marrow. This ultimately leads to lymphopenia or a failure to replenish the lymphocytic system. Glucocorticoid-mediated apoptosis induced by zinc deficiency causes down-regulation of lymphopoiesis. Indeed, zinc itself can modulate death processes in precursor lymphocytes. Finally, there is substantial evidence that zinc supplementation may well reduce the impact of many of the aforementioned diseases by preventing the dismantling of the immune system. The latter represents an important area for research.

Massive xanthomatosis and altered composition of atherosclerotic lesions in hyperlipidemic mice lacking acyl CoA:cholesterol acyltransferase 1

Inhibitors of acyl CoA:cholesterol acyltransferase (ACAT) have attracted considerable interest as a potential treatment for atherosclerosis. Currently available inhibitors probably act nonselectively against the two known ACATs. One of these enzymes, ACAT1, is highly expressed in macrophages in atherosclerotic lesions, where it contributes to foam-cell formation. In this study, we examined the effects of selective ACAT1 deficiency in two mouse models of atherosclerosis. In the setting of severe hypercholesterolemia caused by deficiency in apoE or the LDL receptor (LDLR), total ACAT1 deficiency led to marked alterations in cholesterol homeostasis and extensive deposition of unesterified cholesterol in the skin and brain. Bone marrow transplantation experiments demonstrated that ACAT1 deficiency in macrophages was sufficient to cause dermal xanthomas in hyperlipidemic LDLR-deficient mice. ACAT1 deficiency did not prevent the development of atherosclerotic lesions in either apoE-deficient or LDLR-deficient mice, despite causing relatively lower serum cholesterol levels. However, the lesions in ACAT1-deficient mice were atypical in composition, with reduced amounts of neutral lipids and a paucity of macrophages in advanced lesions. Although the latter findings may be associated with increased lesion stability, the marked alterations in cholesterol homeostasis indicate that selectively inhibiting ACAT1 in the setting of severe hyperlipidemia may have detrimental consequences.

Pyoderma gangrenosum and Chlamydia pneumoniae infection in a diabetic man: pathogenic role or coincidence?

Chlamydia Pneumoniae is not a known cause of skin infections, but unusual pathogens cause chronic infections in diabetic patients. Multiple idiopathic pyoderma gangrenosum-like (PG-like) lesions were refractory to multiple therapeutic agents in a diabetic patient who had C pneumoniae identified by serologic tests and polymerase chain reaction. Based on complete resolution by prolonged anti-chlamydial antibiotic therapy and concomitant decrease in serologic and titers determined by polymerase chain reactions, the PG-like lesions were presumed to be due to C pneumoniae.

Brown recluse spider bites

The bite of the brown recluse spider (BRS) is the most severe arthropod cause of necrotic skin lesions. The severity of cutaneous injury due to BRS bites vary from mild erythema to severe necrosis. Rarely, severe systemic reactions occur. Diagnosis may be difficult, since the victim may not feel the bite or see the spider. Treatment must be individually tailored. Proper treatment, reassurance, and rapid followup are helpful in reducing the cutaneous and psychologic discomfort associated with BRS bites.

Spontaneous alopecia areata-like hair loss in one congenic and seven inbred laboratory mouse strains

Alopecia areata (AA) research has been hampered by the lack of suitable animal models for use in experimental procedures. AA-like hair loss has been observed in several species, including dogs, cats, horses, cattle, and nonhuman primates; however, these examples are isolated cases in outbred species of large size, limiting their use in AA research. Inbred rodent strains are ideal research models. C3H/HeJ mice can develop spontaneous AA-like hair loss and have previously been advanced as a suitable experimental model. The search for additional mouse strains with AA-like hair loss has continued. Nonscarring, inflammatory, spontaneously reversible hair loss has been observed in individual mice from several inbred mouse strains. Aside from C3H/HeJ mice, an AA-like phenotype has been observed in the substrain C3H/HeJBir, with an expression frequency of 5%. Up to 10% of individuals in an A/J mouse colony have been confirmed to develop patchy AA-like hair loss. Isolated examples of AA have also been identified in C3H/HeN/J mice, C3H/OuJ mice, HRS/J+/hr heterozygous normal mice, CBA/CaHN-Btk(xid)/J mice, and BALB.2R-H2h2/Lil mice, each with a colony frequency of less than 1%. BALB.2R-H2h2/Lil mice may also have severe nail defects. AA is regarded as rare in nonhuman species; however, nonscarring inflammatory based alopecia has been identified in several mouse strains. These examples may represent different subtypes of the heterogeneous AA phenotype. Pathologic and genetic analysis of different AA affected mouse strains may contribute to understanding AA pathogenesis and elucidating susceptibility genes.

Basal cell carcinoma of the lower extremities

BACKGROUND

The most common malignancy in the USA is basal cell carcinoma. It is most prevalent on the head and neck, but can occur elsewhere. We sought to determine the frequency of basal cell carcinomas arising on the lower extremities, as well as the gender of affected patients, the histologic subtype, and the specific sites of involvement.

METHODS

We reviewed cases submitted to the Vanderbilt Dermatopathology Service between 1994 and 1997 which were diagnosed as basal cell carcinoma. A subset of 150 cases which arose on the lower extremities and a control group of 150 cases which arose at other anatomic sites were studied further.

RESULTS

A significantly greater number of basal cell carcinomas of the lower extremities arose in women, were of the superficial subtype, and were found below the knee; 59% of basal cell carcinomas in both sexes arose on the right limb.

CONCLUSION

Basal cell carcinomas of the lower extremities occur more often in women in the USA and are of the superficial subtype. This may be due to differing patterns of dress and exposure to the sun.

Tamoxifen-induced remission of psoriasis

Psoriasis vulgaris may be worsened or precipitated by numerous factors, including hormonal influences. Several lines of evidence suggest that female sex hormones such as estrogen and progesterone affect this condition. We describe a patient whose psoriasis responded favorably to administration of the antiestrogen compound tamoxifen.

Alopecia areata: an autoimmune disease?

A wide range of hypotheses such as focal infection, trophoneuroses, and endocrine dysfunction, have been previously proposed to explain the pathogenesis of alopecia areata (AA). Currently, the most widely held belief is that AA is an autoimmune disease with cellular and/or humoral immunity directed against anagen hair follicle antigen(s). However, until recently evidence in support of an autoimmune mechanism of AA has been largely circumstantial. More fundamental evidence has recently been amassed in support of AA as an autoimmune disease by using animal models. These data include: 1) identification of cross-species hair follicle specific IgG autoantibodies, 2) The ability to induce AA in an animal model with transfer of skin from affected to naive individuals, and 3) the induction of disease by transfer of lymphocytes to human skin grafted to severe combined immunodeficiency mutant mice. A review of the previous and current data related to the autoimmune basis of AA is provided to put into perspective the future studies needed to definitively determine whether AA is an autoimmune disease.

Androgenetic alopecia: in vivo models

Androgenetic alopecia is the most common form of balding in humans. There is great interest in finding a reliable animal model to study the pathogenesis and treatment of this abnormality. The sump-tailed macaque (Macaca artoides) has been the standard model and appears to be useful homologue. These primates are reasonably good predictors of compound efficacy. Due to reduced size and expense, rodent models have been sought. Testosterone inducible models require more development but offer potential. Xenografts of human skin to immunodeficient mice, notably nude or severe combined immunodeficiency, are small, relatively inexpensive, and easy to work with if a source of human tissue is available. Xenografts to double mutant mice for severe combined immunodeficiency and a number of hormone receptor null mutations offer new refinements to these xenograft models.

Recalcitrant acne vulgaris secondary to a dental abscess

This case report describes a middle-aged man with acne that was recalcitrant to numerous medications, including three courses of isotretinoin. His condition cleared after an infected tooth was removed and recurred when another tooth became carious. Acne vulgaris is associated with several immunologic responses including the production of antibodies against Propionibacterium acnes, the gram-positive bacteria found in acne lesions. We believe that the presence of our patient's dental infections provoked a follicular inflammatory response resulting in his recalcitrant acne.

Cigarette smoking-associated elastotic changes in the skin

BACKGROUND

Clinical features of the skin in persons who smoke include increased wrinkling, gauntness, and discoloration that has been termed smoker's face. The histologic changes in the sun-exposed skin of these patients have not been previously elucidated.

OBJECTIVE

The purpose of this study was to assess the amount of elastosis in the sun-exposed skin of smokers and nonsmokers.

METHODS

We evaluated the skin from the forehead and cheeks of 17 smokers and 14 nonsmokers for the presence of elastosis. With the use of a computer-generated analysis of tissue sections at 4 different levels, the amount of elastotic material was expressed as an average percent of the field staining for elastic tissue. Patients were also evaluated for the presence of other malignancies, arsenic and radiation exposure, and previous skin cancers.

RESULTS

There was a significantly greater amount of elastosis (P < .05) in the skin of patients who smoked compared with those patients who did not. No significant differences were found between the 2 groups with regard to the other parameters evaluated.

CONCLUSION

Cigarette smoking is associated with an increase in elastosis, which may contribute to the clinical features of "smoker's face."

The North American experience with photopheresis

Photopheresis or extracorporeal photochemotherapy (ECP) is a novel immunomodulatory therapy based upon pheresis of light-sensitive cells. Whole blood is removed from patients who have previously ingested the photosensitizing agent 8-methoxypsoralen (8-MOP) followed by leukapheresis and exposure of the 8-MOP containing white blood cells (WBCs) extracorporeally to an ultraviolet A (UVA) light source prior to their return to the patient. In 1988, the Food and Drug Administration (FDA) approved photopheresis for the treatment of cutaneous T-cell lymphoma (CTCL). Treatment of CTCL with photopheresis has been reported in over 300 patients worldwide. Photopheresis has also demonstrated encouraging results in the treatment of solid organ transplant rejection, graft versus host disease, scleroderma, and other autoimmune diseases although fewer patients have been studied. This review will focus on the North American experience with photopheresis.

Colchicine in dermatology

Colchicine is a medication most often used to treat symptoms of gout. This drug has also been shown to have beneficial effects on cutaneous conditions, including leukocytoclastic vasculitis, psoriasis, and Sweet's syndrome. Colchicine inhibits the function of polymorphonuclear leukocytes, and dermatoses with a strong presence of these cells may benefit the most from the administration of this medication. A review of the pharmacology, mechanism of action, and adverse reactions of colchicine is also presented.