Microscopic Evolution of Laboratory Volcanic Hybrid Earthquakes

Characterizing the interaction between fluids and microscopic defects is one of the long-standing challenges in understanding a broad range of cracking processes, in part because they are so difficult to study experimentally. We address this issue by reexamining records of emitted acoustic phonon events during rock mechanics experiments under wet and dry conditions. The frequency spectrum of these events provides direct information regarding the state of the system. Such events are typically subdivided into high frequency (HF) and low frequency (LF) events, whereas intermediate "Hybrid" events, have HF onsets followed by LF ringing. At a larger scale in volcanic terranes, hybrid events are used empirically to predict eruptions, but their ambiguous physical origin limits their diagnostic use. By studying acoustic phonon emissions from individual microcracking events we show that the onset of a secondary instability-related to the transition from HF to LF-occurs during the fast equilibration phase of the system, leading to sudden increase of fluid pressure in the process zone. As a result of this squeezing process, a secondary instability akin to the LF event occurs. This mechanism is consistent with observations of hybrid earthquakes.

Observation of the Kibble-Zurek Mechanism in Microscopic Acoustic Crackling Noises

Characterizing the fast evolution of microstructural defects is key to understanding "crackling" phenomena during the deformation of solid materials. For example, it has been proposed using atomistic simulations of crack propagation in elastic materials that the formation of a nonlinear hyperelastic or plastic zone around moving crack tips controls crack velocity. To date, progress in understanding the physics of this critical zone has been limited due to the lack of data describing the complex physical processes that operate near microscopic crack tips. We show, by analyzing many acoustic emission events during rock deformation experiments, that the signature of this nonlinear zone maps directly to crackling noises. In particular, we characterize a weakening zone that forms near the moving crack tips using functional networks, and we determine the scaling law between the formation of damages (defects) and the traversal rate across the critical point of transition. Moreover, we show that the correlation length near the transition remains effectively frozen. This is the main underlying hypothesis behind the Kibble-Zurek mechanism (KZM) and the obtained power-law scaling verifies the main prediction of KZM.

Acute generalized exanthematous pustulosis induced by chromium picolinate

A case of acute generalized exanthematous pustulosis (AGEP) due to chromium picolinate is described. This supplemental form of chromium has received a great deal of interest recently because of its possible beneficial effects on both muscle strength and body composition. There have been no previous reports to our knowledge of adverse cutaneous reactions to this agent. Various aspects of AGEP are reviewed.

Deep dermal granuloma annulare presenting as an eyelid tumor in a child, with review of pediatric eyelid lesions

A case of deep dermal granuloma annulare (GA) involving the eyelid of a child is reported. GA presenting in the periocular region is rare and may mimic other lesions. The differential diagnosis of pediatric eyelid lesions is reviewed.

The United States military and leishmaniasis

Leishmaniasis occurs not only in American travelers and military personnel alike but infects a significant portion of the world's population. The US military has made major contributions to the understanding of the complicated epidemiology of this parasite, the development of rapid reliable diagnostic tests, and to the development of safe, more efficient, and more effective treatment of leishmaniasis.

Safety and efficacy of intravenous sodium stibogluconate in the treatment of leishmaniasis: recent U.S. military experience

The efficacy and toxicity of sodium stibogluconate (SSG) at a dosage of 20 mg/(kg.d) for either 20 days (for cutaneous disease) or 28 days (for visceral, mucosal, or viscerotropic disease) in the treatment of leishmaniasis is reported. Ninety-six U.S. Department of Defense health care beneficiaries with parasitologically confirmed leishmaniasis were prospectively followed for 1 year. One patient was infected with human immunodeficiency virus; otherwise, comorbidity was absent. Clinical cure occurred in 91% of 83 cases of cutaneous disease and 93% of 13 cases of visceral/viscerotropic disease. Adverse effects were common and necessitated interruption of treatment in 28% of cases, but they were generally reversible. These included arthralgias and myalgias (58%), pancreatitis (97%), transaminitis (67%), headache (22%), hematologic suppression (44%), and rash (9%). No subsequent mucosal leishmaniasis was identified, and there were no deaths attributable to SSG or leishmaniasis.

Felodipine-induced gingival hyperplasia

Felodipine is a calcium channel blocking agent used in the management of hypertension and angina. We report a case of gingival hyperplasia in a patient with chronic use of this drug. Gingival changes occurred soon after initiation of felodipine and improved upon its discontinuation. The clinical characteristics, inciting agents, proposed pathogenetic mechanisms, as well as prevention and treatment of drug-induced gingival hyperplasia are briefly reviewed.

Acinic cell carcinoma presenting as an upper lip mass

BACKGROUND

Acinic cell carcinoma (ACC) is a rare tumor generally involving the parotid gland and infrequently the minor salivary glands.

OBJECTIVE

Clinical and histopathological characteristics of a case of ACC of the minor salivary glands, and brief review of the literature.

METHODS

Routine stains with H&E, PAS, iron, and mucicarmine; immunohistochemistry with cytokeratin, CEA, S-100, and leu-M1.

RESULTS

The ACC was removed by wide local excision. Histopathology revealed papillary cystic, solid, and ductal architectural features. The mucinous material within the lumina of the cystic and ductal structures was PAS and mucicarmine positive, and diastase resistant. All tested immunohistochemical reagents reacted with the epithelial cells. There were no mitoses, necrosis, cellular pleomorphism, or infiltration.

CONCLUSIONS

ACC is a rare tumor of salivary glands characterized by an indolent clinical course with the potential for both local recurrence and metastatic spread when tracked for decades. Published mortality rates vary from 6 to 50%. Histopathologic features do not reliably predict biologic behavior.

Cutaneous angiosarcoma arising in the radiation site of a congenital hemangioma

We describe a patient in whom angiosarcoma developed at the site of a hemangioma that was treated during infancy with radiation for refractory thrombocytopenia. Our findings, along with those of the 10 reported cases from the world literature, are summarized. One third of angiosarcomas arise in the skin. They most often show one of three clinical patterns. First and most common is occurrence as a bruiselike lesion on the scalp or face of an elderly person. Second in frequency is the Stewart-Treves syndrome. Third and least common is angiosarcoma developing as a sequela of previous radiation therapy. The prognosis in general is poor, with a mean survival length of 24 months and a 5-year survival rate of 10%. Effective treatment relies on early diagnosis and wide-margin surgical excision.

Essential syphilitic alopecia revisited

There has been a resurgence of syphilis in the past decade. Uncommonly, diffuse hair loss, termed essential alopecia, is the only sign of syphilitic infection. We describe two patients with syphilis in whom the first sign of disease was alopecia and discuss the clinical and histopathologic findings of essential syphilitic alopecia.

Phialophora verrucosa: a new cause of mycetoma

A 29-year-old Thai woman had draining sinus tracts, tumefaction, and granules on the plantar aspect of the foot. Phialophora verrucosa was isolated from the lesion. P. verrucosa is a major agent of chromoblastomycosis, which is known to rarely cause subcutaneous phaeohyphomycosis. This dematiaceous fungus has not been previously reported to cause mycetoma. This case illustrates the clinical spectrum of disease of this fungus. The salient features of mycetoma and management options are presented.

A dose-ranging study of the efficacy and safety of azelastine nasal spray in the treatment of seasonal allergic rhinitis with an acute model

BACKGROUND

Oral azelastine, a nonsteroidal antiinflammatory respiratory investigational drug has demonstrated activity in the treatment of allergic rhinitis and asthma with a good safety profile.

METHODS

Azelastine nasal spray was compared with sustained-release oral chlorpheniramine maleate and placebo for efficacy and safety in the treatment of seasonal allergic rhinitis in a double-dummy, two-center, 2-day, double-blind, randomized, dose-ranging, parallel-groups, onset and duration of action study. Two hundred sixty-four subjects reported to an outdoor park on Saturday morning during the height of the fall pollen season and remained there for 8 hours that day and the next to ensure maximal exposure to seasonal aeroallergens. Symptom diary cards were collected hourly Saturday from 8:00 AM to 10:00 AM (baseline period). Subjects who had sufficient symptoms were randomized into five groups and received medication at 10:00 AM and 10:00 PM on Saturday and at 10:00 AM on Sunday: azelastine 0.1% (1 spray [0.12 mg] per nostril every 12 hours, 2 sprays per nostril every every 12 hours, or 2 sprays per nostril once daily), Chlor-Trimeton Repetabs (12 mg twice daily), or placebo (twice daily). Diary cards were completed hourly (11:00 AM to 4:00 PM) and at 6:00, 8:00, and 10:00 PM on Saturday and again hourly on Sunday (from 8:00 AM to 4:00 PM) to evaluate rhinitis symptoms and adverse events.

RESULTS

Two hundred fifty-nine subjects completed the study. The groups that received 2 sprays of azelastine per nostril once and twice daily and the chlorpheniramine group had statistically significantly more improvement in total rhinitis symptoms than the placebo group without serious adverse events.

CONCLUSIONS

This study supports a once to twice daily dosing regimen for 2 sprays of 0.1% azelastine in the acute treatment of allergic rhinitis with onset of action within 2 to 3 hours.

Hypereosinophilic syndrome associated with HIV infection. Military Medical Consortium for Applied Retroviral Research

A hypereosinophilic syndrome associated with dermatitis has been observed rarely in association with HIV infection. We describe the case of a young man with AIDS who came to us with a diffuse cutaneous eruption, fever, angioedema, eosinophilia, and a mildly elevated serum IgE level. No allergic or infectious cause of this illness could be determined, and the patient was treated with corticosteroids and PUVA therapy, resulting in complete resolution of the dermatitis and associated findings. In this case, there were clinical and histopathologic similarities to the idiopathic hypereosinophilic syndrome and to acute graft-versus-host disease. The serum level of the cytokine interleukin-5 (IL-5), which is associated with eosinophil production, was found to be mildly elevated during the peak of the eruption, while samples drawn previously and subsequently were not. Although it appears that the syndrome we describe is associated with the measurably elevated level of IL-5, further investigation is required to determine whether there is a cause and effect relationship between IL-5 and this entity. A brief review of the literature concerning eosinophils and HIV infection is also presented in the context of this case.

Rapid diagnosis of coccidioidomycosis with a DNA probe to ribosomal RNA

BACKGROUND

Although nucleic acid probe hybridization assays were previously exclusively used as a tool in the research setting, such assays have recently become commercially available for the detection of a variety of infectious microorganisms.

OBSERVATIONS

We used a commercially available DNA hybridization probe test that targets organism-specific ribosomal RNA sequences to rapidly diagnose a patient with disseminated coccidioidomycosis. The natural amplification inherent to such DNA:RNA probe systems obviates the need for electrophoretic separation and amplification steps, which are often required in more traditional DNA:DNA probe assays. With this probe, culture confirmation was obtained within 48 hours after the clinical specimens were received.

CONCLUSION

Rapid DNA hybridization probe techniques have wide application in infectious diseases, especially those characterized by slow culture growth of pathogens such as deep fungi and atypical mycobacteria.

Childhood localized vulvar pemphigoid is a true variant of bullous pemphigoid

BACKGROUND

Childhood localized vulvar pemphigoid has been recently reported in four girls. A fifth child with this proposed rare variant of bullous pemphigoid is described. Moreover, findings in the various immunopathologic studies we performed establish this entity as a true morphologic variant of bullous pemphigoid.

OBSERVATIONS

In situ deposits of IgG in this patient's epidermal basement membrane zone localized to the epidermal side of 1 mol/L of saline-split skin. Moreover, the patient had circulating IgG autoantibodies that bound the epidermal side of 1 mol/L of saline-split skin in indirect immunofluorescence microscopy and immunoprecipitated the 230-kd bullous pemphigoid antigen from biosynthetically radiolabeled human keratinocyte extracts. These laboratory findings are identical to those documented in patients with the generalized "classic" form of bullous pemphigoid.

CONCLUSIONS

This study demonstrates that a child with clinical, histopathologic, and immunopathologic features of localized vulvar pemphigoid had circulating autoantibodies that identify a specific keratinocyte antigen, the bullous pemphigoid antigen, which may serve as a molecular marker for this disease.

Long-term therapy with low-dose isotretinoin for prevention of basal cell carcinoma: a multicenter clinical trial. Isotretinoin-Basal Cell Carcinoma Study Group

BACKGROUND

High-dose isotretinoin has been reported to have a prophylactic effect on nonmelanoma skin cancer, although it is associated with significant toxicity.

PURPOSE

To test the effectiveness of the long-term administration of low-dose isotretinoin in reducing the occurrence of basal cell carcinoma at a new site in patients with previously treated basal cell carcinomas and to measure the toxicity associated with this regimen, we conducted a clinical trial at eight cancer centers.

METHODS

Nine hundred and eighty-one patients with two or more previously confirmed basal cell carcinomas were randomly assigned to receive either 10 mg of isotretinoin or a placebo daily. Patients were followed for 36 months and monitored at 6-month intervals for skin cancer and toxic effects.

RESULTS

After 36 months of treatment, no statistically significant difference in either the cumulative percent of patients with an occurrence of basal cell carcinoma at a new site or the annual rate of basal cell carcinoma formation existed between patients receiving isotretinoin and those receiving the placebo. Elevated serum triglycerides, hyperostotic axial skeletal changes, and mucocutaneous reactions were more frequent in the group receiving isotretinoin than in the control group, and these differences were all statistically significant (P less than .001).

CONCLUSION

This low-dose regimen of isotretinoin not only is ineffective in reducing the occurrence of basal cell carcinoma at new sites in patients with two or more previously treated basal cell carcinomas but also is associated with significant adverse systemic effects.

IMPLICATION

The toxicity associated with the long-term administration of isotretinoin, even at the low dose used in this trial, must be weighted in planning future prevention trials.

Epithelioid hemangioendothelioma associated with reflex sympathetic dystrophy

A patient with long-standing reflex sympathetic dystrophy of the foot developed an aggressive epithelioid hemangioendothelioma of the involved extremity. The tumor metastasized to a regional lymph node and later to the lungs. The features of epithelioid hemangioendothelioma and reflex sympathetic dystrophy are reviewed.

Transient, nonpigmenting fixed drug eruption caused by radiopaque contrast media

A unique case of a transient, nonpigmenting fixed drug eruption caused by the radiopaque contrast medium iothalamate is reported. The patient had on the medial aspect of the thigh a fixed solitary, recurrent, indurated, erythematous plaque, which resolved within 2 days. The scant literature available on nonpigmenting fixed drug eruptions is reviewed.

Cutaneous and ocular manifestations of Down syndrome

A patient with Down syndrome and extensive elastosis perforans serpiginosa is presented. There is an increased incidence of elastosis perforans serpiginosa, alopecia areata, syringomas, and Norwegian scabies in patients with this syndrome. Ocular findings include slanting of the palpebral fissures, Brushfield's spots, nystagmus, and epicanthal folds. Serious ocular complications that may impair vision include keratoconus, congenital cataracts, and retinal detachment.

A prospective study of the risk of an immediate adverse reaction to protamine sulfate during cardiopulmonary bypass surgery

Protamine sulfate administration may cause life-threatening reactions. We prospectively examined the incidence of immediate adverse reaction after protamine in 243 patients who underwent cardiopulmonary bypass surgery. Twenty-six patients (10.7%) had reactions, and 1.6% had a precipitous drop in blood pressure immediately after protamine administration. Risk factors were previous exposure to protamine, diabetes, history of receiving protamine-containing insulin, and possibly vasectomy. However, neither a positive skin test nor a positive IgE ELISA for antiprotamine antibody predicted that a patient would have a reaction. C4a levels were increased in patients who had reactions as compared with age-, sex-, and cardiac disease-matched patients who did not have reactions, suggesting a role for complement in some reactions. Immediate adverse reactions to protamine are very common, and alternative therapies are urgently needed to eliminate the use of protamine.

Cutaneous myiasis caused by the African tumbu fly (Cordylobia anthropophaga)

We describe a patient with cutaneous myiasis caused by the African tumbu fly (Cordylobia anthropophaga). This case demonstrates the need for a detailed travel history and an understanding of the fly life cycle to prevent erroneous diagnosis and to expedite prompt treatment. The nature of the lesions, larval morphological features, histological characteristics, and immune response directed toward fly maggots are described.

Basal cell carcinoma of the nipple. Report of two cases

Two cases of basal cell carcinoma of the nipple are presented, bringing the total number of reported cases to 15. The majority, including our two patients, are elderly men. This finding suggests a causal role of exposure to ultraviolet radiation. In our cases excision was curative.

Rheumatoid neutrophilic dermatitis

We recently examined a patient with severe rheumatoid arthritis who presented clinically with fixed urticaria-like plaques. Histologic examination revealed a dense neutrophilic dermal infiltrate without associated vasculitis. On clinical and histologic grounds, this case differs from other noninfectious neutrophilic inflammatory disorders. We present a case of rheumatoid neutrophilic dermatitis and review the salient features of this unique disorder.

Proteus syndrome

The term Proteus syndrome was coined in 1983 to describe a disorder of skeletal, hamartomatous, and other mesodermal malformations. The syndrome was named after the Greek god Proteus, whose name means "the Polymorphous." Clinical features of this new syndrome are currently being defined. Including the case reported herein, we have found 34 patients with Proteus syndrome described in the English literature. Major clinical findings, defined as those findings seen in more than half of the cases, include hemihypertrophy, macrodactyly, exostoses, epidermal nevi, characteristic cerebriform masses involving the plantar or palmar surfaces, a variety of subcutaneous masses, and scoliosis. Histologic examination of subcutaneous masses has identified a variety of lipomatous, hamartomatous, and angiomatous tumors.

The ridgeback anomaly. A new follicular pattern of the scalp

A patient with an anomaly of hair pattern development is described. Scalp hair follicles generally grow at a downward inclination to the scalp surface. Normal whorled patterns appear in the posteroparietal area. The patient described was noted to have a whorled hair pattern located over the right temporoparietal region, growing in a clockwise direction. The remainder of the scalp adopted the upward follicular growth pattern of the posterior portion of the whorl, directed toward the apical anatomic axis. A ridge of hair over the nape of the neck reversed direction, similar to hair growth on the Rhodesian Ridgeback dog, growing in a downward manner. The relationship of this new hair pattern to current theories of scalp hair pattern development is reviewed.

Basal cell carcinomas arising in chronic lymphedema

A unique case is presented of basal cell carcinomas arising in chronic lymphedema of the lower extremity. The lesions were successfully treated with the CO2 laser.

Seronegative secondary syphilis in a patient infected with the human immunodeficiency virus (HIV) with Kaposi sarcoma. A diagnostic dilemma

Reagin and treponemal antibody tests are highly reliable in diagnosing secondary syphilis. However, patients infected with the human immunodeficiency virus (HIV) respond abnormally to antigenic stimulation and may fail to develop typical serologic responses to infections. We report the case of an HIV-infected man with Kaposi sarcoma and secondary syphilis whose VDRL test and fluorescent treponemal antibody-absorbed test were repeatedly nonreactive. Correct diagnosis required biopsy of a skin lesion with silver staining to show spirochetes. Clinicians treating HIV-infected patients should be aware of the problems of serologic diagnosis of syphilis in these patients. Biopsy samples of appropriate tissues and staining for spirochetes may be needed to arrive at the correct diagnosis.

White piedra

White piedra, a fungal infection caused by Trichosporon cutaneum, has been reported in Europe, South America, and the Orient. A few cases have also been reported in the United States, all of them acquired as well in this country. A patient whose condition was diagnosed in California apparently contracted white piedra while visiting Panama, demonstrating that tropical diseases may occasionally be found at great distances from their point of origin. Therapy with topical clotrimazole and removal of infected hairs by shaving failed to produce a clinical or culturally confirmed cure in this patient.

Evaluation of the mutagenic potential of mycotoxins using Salmonella typhimurium and Saccharomyces cerevisiae

The mutagenic effects of fiteen mycotoxins on Salmonella typhimurium strains TA1535, TA1537 and TA1538 and Saccharomyces cerevisiae strain D-3 were tested. Only aflatoxin B1 and sterigmatocystin were mutagenic. Both were active against S. typhimurium strain TA1538 and S. cerevisiae strain D-3; however, both required activation by the hepatic S-9 enzyme preparation. A positive correlation between the other mycotoxins reported to be carcinogenic and the two in vitro test systems employed was not demonstrated in our hands.