Symmetrical Skin Lesions on the Gluteal Region in a Patient with Anti-Laminin-332 Mucous Membrane Pemphigoid

Mucous membrane pemphigoid (MMP), previously called cicatricial pemphigoid, is a rare subepidermal immunobullous disorder that primarily affects the mucous membranes (1,2). MMP is divided into two major subtypes, anti-BP180-type MMP and anti-laminin-332 (previously called laminin 5 or epiligrin) MMP. Anti-laminin-332 MMP is known to be associated with malignant tumors (3), which may cause overexpression of autoantibodies and induce autoimmunity to laminin-332 (4). MMP primarily affects the mucous membranes, and widespread skin lesions are rare. In MMP, circumscribed skin lesions have been previously reported as occurring on the head, neck, and upper trunk (5). We report a case of anti-laminin-332 MMP presenting with symmetrical skin lesions characteristic of MMP on the weight-bearing areas of the gluteal region. A 66-year-old Japanese man presented with a month-long history of multiple erosions and blisters on the mucous membranes and skin, with conjunctival hyperemia, nasal obstruction, oral pain, and hoarseness of voice. Three days before the first visit, he was diagnosed with gastric cancer with liver metastasis by gastrointestinal endoscopy and abdominal ultrasound examination for tarry stool. Physical examination demonstrated erosions and tense bullae on the conjunctivae, tongue, and lips (Figure 1, a,b), as well as erosive erythematous skin lesions on the nape, right index finger, both legs, and symmetric lesions on the gluteal region (Figure 1, c). His body weight was 86 kg. Laboratory examinations showed slight liver dysfunction and elevation of C-reactive protein levels. Histopathologic examination of the skin lesions demonstrated subepidermal blisters with lymphocytic and eosinophilic infiltrates (Figure 1, d,e). Direct immunofluorescence (IF) revealed linear deposits of IgG and C3, but not IgA, along the basement membrane zone (BMZ) (Figure 1, f,g). An IgG subclass study showed IgG1 and IgG4 deposits. Indirect IF on normal human skin revealed weak positivity for IgA anti-keratinocyte cell surface antibodies and IgG anti-BMZ antibodies, which were bound to the dermal side of 1 mol/L NaCl-split skin (Figure 1, h). IgG immunoblot analyses of both normal human epidermal and dermal extracts showed negative results (including BP230, BP180, 290 kDa type VII collagen, and 200 kDa laminin-γ1). Immunoprecipitation using radio-labeled cultured keratinocyte lysate demonstrated positive reactivity with laminin-332 (Figure 1, i). We established the diagnosis of anti-laminin-332 MMP. We started treatment with oral minocycline (200 mg/day) and niacinamide (900 mg/day) with topical corticosteroids without any effect after 2 weeks of therapy. Administration of oral prednisolone (40 mg/day) with topical corticosteroids and alprostadil ointment on the skin lesions, as well as beclometasone dipropionate powder on the oral lesions resulted in significant improvement of mucocutaneous lesions within 10 days. Although the gastric cancer and liver metastasis initially responded to chemotherapy with fluorouracil and cisplatin, the patient succumbed to multiple organ failure 9 months after the initial visit. Anti-laminin-332 antibodies were originally detected by immunoprecipitation, as in our case. Immunoblotting of purified human laminin-332 have been subsequently developed, which detects the 165/145 kDa α3, 140 kDa β3, and 105 kDa γ2 subunits of laminin-332 in various patterns (6). Today, the ELISA system uses laminin-332 preparations as adjunct diagnostic tools in MMP (7). Occasionally, a wide spectrum of autoantibodies is detected in MMP, for example, MMP with IgG antibodies to both BP180 and laminin-332, which were considered to be developed via epitope spreading. Detection of circulating IgA autoantibodies against the skin have also been reported in MMP (8). However, the pathogenic significance and mechanisms of coexistence of IgG anti-laminin-332 antibodies and IgA anti-keratinocyte cell surface antibodies found in our case are currently unknown. It is generally considered that IgG1 antibodies activate complements and are pathogenic in MMP, while IgG4 antibodies behave as blocking antibodies and are protective. In our case, direct IF revealed IgG1 and IgG4 deposits; the same was reported in a previous case report (9). The pathogenic roles of autoantibodies with different IgG subclasses need to be analyzed in further studies. Conjunctival mucosal lesions in MMP may occur by rubbing of the eyes due to irritation. Blinking subjects the conjunctivae to repeated friction. Vocal cords vibrate during breathing and speaking. The tongue moves while eating and drinking; in particular, the tip of the tongue gets into frequent contact with the inner sides of the incisor teeth. In the present case, characteristic symmetrical skin lesions were seen on the weight-bearing areas of the gluteal region on bony prominences which receive mechanical stresses in the sitting position. These skin lesions were subjected to repeated stretch and pressure stresses, but no ischemic changes were observed, such as decubitus ulcers. Therefore, the symmetrical skin lesions in the gluteal region as well as the ocular and oral mucosal lesions seen in our patient might have resulted from the same mechanism of pathogenesis. We reported a case of anti-laminin-332 MMP presenting with symmetrical gluteal skin lesions, probably induced by mechanical stress. MMP primarily affects the mucous membranes, and widespread skin lesions are rare. Our case emphasizes that clinicians need to specifically check for the presence of skin lesions on weight-bearing parts of the body during examination of patients with suspected MMP.

A case of neonate effectively treated with everolimus for giant hepatic hemangioma complicated with congenital duodenal atresia and Kasabach-Merritt syndrome

BACKGROUND

Disseminated intravascular coagulation (DIC) with Kasabach-Merrit syndrome from a large hepatic hemangioma is life-threatening. We report a case of giant hepatic hemangioma of the newborn with KMS.

RESULTS

The patient was born at 37 gestational weeks and 2 days via cesarean section; weight at birth was 2952 g. Congenital duodenal atresia was noted during the fetal period. DIC developed after delivery and a giant liver hemangioma was diagnosed via abdominal CT. The cause of DIC was Kasabach-Merritt syndrome owing to a giant hepatic hemangioma. First, combination therapy of 2 mg/kg/day of prednisolone and 0.2 mg/kg/day of propranolol was initiated form enterostomy. However, the size of the hepatic hemangioma did not alter, as observed via image evaluation. Therefore, 0.3 mg/kg/day of everolimus was administered frorm enterostomy. Subsequently, the size of the hepatic hemangioma was assessed via image evaluation. Although it did not alter, blood flow to the hepatic hemangioma decreased and thrombocytopenia was also suppressed. We performed hepatic lateral segmentectomy, radical operation for duodenal atresia. The pathological diagnosis of the removed tumor was infantile hemangioma.

CONCLUSION

We report everolimus may be useful when PSL and propranolol are ineffective.

Atypical protein kinase C isoforms differentially regulate directional keratinocyte migration during wound healing

BACKGROUND

The epidermis possesses regenerative properties that become apparent only after wounding. Atypical protein kinase C (aPKC) isoforms aPKCζ and aPKCλ form a ternary complex with Par3 and Par6, and play crucial roles in establishing and maintaining epithelial cell polarity. The epidermal loss of aPKCλ results in progressive depletion of hair follicle stem cells. However, it is unclear whether aPKCs have equivalent activities in epidermal regeneration.

OBJECTIVES

To clarify functional differences between aPKCζ and aPKCλ in cutaneous wound healing.

METHODS

We compared cutaneous wound healing processes in vivo using mutant mice with genetic deletion of each aPKC isoform. We also analyzed functional differences between aPKCζ and aPKCλ in cell proliferation, directional cell migration, and formation of microtubules in vitro using primary keratinocytes established from each mutant mouse.

RESULTS

Wound healing was significantly retarded in epidermis-specific aPKCλ knockout mice. In aPKCλ-deleted keratinocytes, the correct orientation of cell protrusions toward the wound was disrupted through the destabilization of Par6β. The elongation of stabilized β-tubulin was also deteriorated in aPKCλ-deleted keratinocytes, leading to defects in cell spreading. Conversely, wound healing and directional cell migration in aPKCζ-deleted mice were comparable to those in their control littermates.

CONCLUSIONS

aPKCs are not functionally equivalent; aPKCλ, but not aPKCζ, plays a primary role in cutaneous wound healing.

Measurement of trihydroxy-linoleic acids in stratum corneum by tape-stripping: Possible biomarker of barrier function in atopic dermatitis

Epidermal ceramides are indispensable lipids that maintain the functions of the stratum corneum. Esterified omega-hydroxyacyl-sphingosine (EOS) ceramide with a linoleate moiety is one of the most important ceramide species for forming cornified lipid envelopes. This linoleate moiety is eventually metabolized to trihydroxy-linoleic acid (triol, 9,10,13-trihydroxy-11E-octadecenoic acid). Thus, we assumed that a decrease of triols might reflect skin barrier dysfunction. Against this background, the purposes of this study were to measure the triols by a simple tape-stripping method and to determine the correlation between the amount of triols and transepidermal water loss (TEWL) as an indicator of barrier dysfunction in atopic dermatitis patients. Twenty Japanese subjects with normal skin and 20 atopic dermatitis patients were enrolled in this study. TEWL was measured and triols of the stratum corneum were analyzed by tape-stripping. The results showed for the first time that triols in the stratum corneum could be simply measured using the tape-stripping method. The triol levels in atopic dermatitis patients were much higher than those in healthy subjects. Moreover, the triol levels correlated with TEWL of non-lesional forearm skin in patients with atopic dermatitis. The results suggest that the assaying of triol levels via non-invasive tape-stripping could be beneficial for monitoring barrier function in atopic dermatitis.

The first nationwide surveillance of antibacterial susceptibility patterns of pathogens isolated from skin and soft-tissue infections in dermatology departments in Japan

To investigate the trends of antimicrobial resistance in pathogens isolated from skin and soft-tissue infections (SSTI) at dermatology departments in Japan, a Japanese surveillance committee conducted the first nationwide survey in 2013. Three main organisms were collected from SSTI at 30 dermatology departments in medical centers and 10 dermatology clinics. A total of 860 strains - 579 of Staphylococcus aureus, 240 of coagulase-negative Staphylococci, and 41 of Streptococcus pyogenes - were collected and shipped to a central laboratory for antimicrobial susceptibility testing. The patient profiles were also studied. Among all 579 strains of S. aureus, 141 (24.4%) were methicillin-resistant (MRSA). Among 97 Staphylococcus epidermidis strains, 54 (55.7%) were methicillin-resistant (MRSE). MRSA and MRSE were more frequently isolated from inpatients than from outpatients. Furthermore, these methicillin-resistant strains were also isolated more frequently from patients with histories of taking antibiotics within 4 weeks and hospitalization within 1 year compared to those without. However, there were no significant differences in MIC values and susceptibility patterns of the MRSA strains between patients with a history of hospitalization within 1 year and those without. Therefore, most of the isolated MRSA cases at dermatology departments are not healthcare-acquired, but community-acquired MRSA. S. pyogenes strains were susceptible to most antibiotics except macrolides. The information in this study is not only important in terms of local public health but will also contribute to an understanding of epidemic clones of pathogens from SSTI.

A randomized double-blind trial of intravenous immunoglobulin for bullous pemphigoid

BACKGROUND

Patients with steroid-resistant bullous pemphigoid (BP) require an appropriate treatment option.

OBJECTIVE

A multicenter, randomized, placebo-controlled, double-blind trial was conducted to investigate the therapeutic effect of high-dose intravenous immunoglobulin (IVIG; 400mg/kg/day for 5days) in BP patients who showed no symptomatic improvement with prednisolone (≥0.4mg/kg/day) administered.

METHODS

We evaluated the efficacy using the disease activity score on day15 (DAS15) as a primary endpoint, and changes in the DAS over time, the anti-BP180 antibody titer, and safety for a period of 57days as secondary endpoints.

RESULTS

We enrolled 56 patients in this study. The DAS15 was 12.5 points lower in the IVIG group than in the placebo group (p=0.089). The mean DAS of the IVIG group was constantly lower than that of the placebo group throughout the course of observation, and a post hoc analysis of covariance revealed a significant difference (p=0.041). Furthermore, when analyzed only in severe cases (DAS≥40), the DAS15 differed significantly (p=0.046). The anti-BP180 antibody titers showed no difference between the two groups.

CONCLUSION

IVIG provides a beneficial therapeutic outcome for patients with BP who are resistant to steroid therapy.

Comparative studies of the marginal band and plasma membrane of the epidermis

The membranous fraction isolated from stratum corneum by 8M urea-beta ME containing alkaline buffer (pH 9.0) is quite crude when observed by electron microscopy. However, this procedure may be useful for clinical samples, as one can isolate and compare both the soluble (interfilamentous) fraction and the keratin filament from the same sample in addition to the residues (membranous fraction). A further purified membranous fraction was isolated by a new method. Human stratum corneum was chopped and treated with 8M urea-50 mM Tris-HCl (pH 9.0), digested by the use of trypsin, and the product fractionated by a sucrose density gradient to obtain separate single cells without the cytoplasm. One sample was then treated with trypsin for 1 hour and another with urea buffer for 24 hours. Observations revealed a thickened inner membrane (marginal band) of approximately 150A. Each of the membranous samples contained a level of half-cystine markedly higher in amount (around 100/1,000) and involved mostly in the epsilon-(gamma-glutamyl) lysine cross-linkages (around 30%). In order to compare the membranous fraction of horny and living cells (marginal bands and plasma membranes), the fraction was then isolated from living cells. The relative amino acid composition of the membranous fraction of the plasma membrane resembled that of human erythrocytes, but was quite different from that of the marginal band. These comparative studies of biochemical and morphological features suggested the importance of S-S cross-linking enzymes and transglutaminase in the transformation mechanism of the marginal band.

Possible Spontaneous Regression of a Metastatic Lesion of Keratoacanthoma-Like Squamous Cell Carcinoma in a Regional Lymph Node

We report herein a case of keratoacanthoma-like squamous cell carcinoma in an 82-year-old male that showed regional lymph node metastasis followed by self-regression of the metastatic lesion. This case is consistent with the previously reported observation that tumors compatible with the clinical features of keratoacanthoma may have malignant biological potential, however, it also demonstrates that even metastatic lesions may exhibit self-regression similar to that observed for primary lesions. Despite the view that keratoacanthoma-like squamous cell carcinoma may represent a variant of squamous cell carcinoma, occasionally it undergoes a unique clinical course.

The "push-down" technique using a novel micro-forceps for microvascular venous coupling

A microvascular coupling system was developed and introduced for clinical application to facilitate fast and safe anastomosis of small vessels. However, operators often encounter some difficulty, particularly in pinning the vascular wall onto the ring-pins. To overcome the difficulty, the authors developed the "push down" technique and made newly-designed micro-forceps. These forceps have been used in 111 venous couplings involving 96 critical anastomoses. This study reports herein the patency results showing effectiveness and safety of the "push down" technique using a prototype micro-forceps in the pinning procedure in a microvascular coupling system.

Suppression of choriocarcinoma invasion and metastasis following blockade of BDNF/TrkB signaling

Brain-derived neurotrophic factor (BDNF) acts through its cognate receptor tyrosine kinase-B (TrkB) to regulate diverse physiological functions in reproductive and other tissues. In normal and malignant trophoblastic cells, the BDNF/TrkB signaling promotes cell growth. Due to the highly malignant nature of choriocarcinoma, we investigated possible involvement of this system in choriocarcinoma cell invasion and metastasis. We demonstrated that treatment of cultured choriocarcinoma cells, known to express both BDNF and TrkB, with a soluble TrkB ectodomain or a Trk receptor inhibitor K252a suppressed cell invasion accompanied with decreased expression of matrix metalloproteinase-2, a cell invasion marker. In vivo studies using a tumor xenograft model in athymic nude mice further showed inhibition of cell invasion from tumors to surrounding tissues following the suppression of endogenous TrkB signaling. For an in vivo model of choriocarcinoma metastasis, we performed intravenous injections of JAR cells expressing firefly luciferase into severe combined immunodeficiency (SCID) mice. Treatment with K252a inhibited metastasis of tumors to distant organs. In vivo K252a treatment also suppressed metastatic tumor growth as reflected by decreased cell proliferation and increased apoptosis and caspases-3/7 activities, together with reduced tissue levels of a tumor marker, human chorionic gonadotropin-β. In vivo suppression of TrkB signaling also led to decreased expression of angiogenic markers in metastatic tumor, including cluster of differentiation 31 and vascular endothelial growth factor A. Our findings suggested essential autocrine/paracrine roles of the BDNF/TrkB signaling system in choriocarcinoma invasion and metastasis. Inhibition of this signaling could serve as the basis to develop a novel therapy for patients with choriocarcinoma.

Immunoglobulin prophylaxis against cytomegalovirus infection in patients at high risk of infection following allogeneic hematopoietic cell transplantation

Reports on the efficacy of intravenous immunoglobulin (IVIG) prophylaxis against cytomegalovirus (CMV) infection after allogeneic hematopoietic cell transplantation (HCT) have often sparked controversy. In addition, we are not aware of any study that has examined whether prophylaxis with IVIG affects the incidence of CMV infection in high-risk patients--those who are elderly or have received human leukocyte antigen (HLA) mismatched HCT. In the present open-label, phase II study, we addressed this question. We enrolled 106 patients in the study. The cumulative incidences of CMV infection at 100 days after HCT were similar in the intervention and the control groups (68% and 64%, P=.89; 89% and 87%, P=.79, respectively, for patients 55 years or older and those who received HLA-mismatched HCT). In those who received HLA-mismatched HCT, 1-year overall survival after HCT was 46% in the intervention group and 40% in the control group (P=.31); for age≥55 years, the corresponding values were 46% and 40% (P=.27). Our data showed that prophylaxis with regular polyvalent IVIG did not affect the incidence of CMV infections or survival among older patients or those who receive HLA-mismatched HCT.

Prevalence of dermatological disorders in Japan: a nationwide, cross-sectional, seasonal, multicenter, hospital-based study

To clarify the prevalence of skin disorders among dermatology patients in Japan, a nationwide, cross-sectional, seasonal, multicenter study was conducted in 69 university hospitals, 45 district-based pivotal hospitals, and 56 private clinics (170 clinics in total). In each clinic, information was collected on the diagnosis, age, and gender of all outpatients and inpatients who visited the clinic on any one day of the second week in each of May, August, and November 2007 and February 2008. Among 67,448 cases, the top twenty skin disorders were, in descending order of incidence, miscellaneous eczema, atopic dermatitis, tinea pedis, urticaria/angioedema, tinea unguium, viral warts, psoriasis, contact dermatitis, acne, seborrheic dermatitis, hand eczema, miscellaneous benign skin tumors, alopecia areata, herpes zoster/postherpetic neuralgia, skin ulcers (nondiabetic), prurigo, epidermal cysts, vitiligo vulgaris, seborrheic keratosis, and drug eruption/toxicoderma. Atopic dermatitis, impetigo, molluscum, warts, acne, and miscellaneous eczema shared their top-ranking position in the pediatric population, whereas the most common disorders among the geriatric population were tinea pedis, tinea unguium, psoriasis, seborrheic dermatitis, and miscellaneous eczema. For some disorders, such as atopic dermatitis, contact dermatitis, urticaria/angioedema, prurigo, insect bites, and tinea pedis, the number of patients correlated with the average high and low monthly temperatures. Males showed a greater susceptibility to some diseases (psoriasis, erythroderma, diabetic dermatoses, inter alia), whereas females were more susceptible to others (erythema nodosum, collagen diseases, livedo reticularis/racemosa, hand eczema, inter alia). In conclusion, this hospital-based study highlights the present situation regarding dermatological patients in the early 21st century in Japan.

Inhibition of brain-derived neurotrophic factor/tyrosine kinase B signaling suppresses choriocarcinoma cell growth

Brain-derived neurotrophic factor (BDNF) signals through its receptor tyrosine kinase (Trk)B to regulate the development trophoblast cells during peri- and postimplantation periods. Possible involvement of this signaling system in malignant human trophoblastic cell growth has not been investigated. Here, we found the expression of BDNF and neurtropin-4/5 together with TrkB in human trophoblastic choriocarcinoma cells. Treatment of cultured choriocarcinoma cells with a soluble TrkB ectodomain or a Trk receptor inhibitor K252a suppressed cell proliferation and increased apoptosis associated by the disruption of mitochondrial functions, whereas an inactive plasma membrane nonpermeable K252b was ineffective. Studies using these specific inhibitors also indicated the importance of the phosphatidylinositol 3-kinase and ERK pathways in mediating BDNF actions. Based on PCR array analyses to identify changes in expression profiles of cell cycle- and apoptosis-related genes in cultured choriocarcinoma cells, we found that suppression of endogenous TrkB signaling led to decreases in key proproliferation cell cycle genes and increases in two inhibitory cell cycle genes together with the up-regulation of several proapoptotic genes. In vivo studies in athymic nude mice bearing choriocarcinoma cell tumors further demonstrated that treatment with K252a, but not K252b, suppressed tumor growth accompanied by decreased cell proliferation, reduced levels of a tumor marker, human chorionic gonadotropin-beta, and increased levels of apoptosis and caspase-3/7 activities. Thus, autocrine signaling of the BDNF/TrkB system is important for human choriocarcinoma cell growth, and inhibition of BDNF/TrkB signaling in these cells could provide a novel therapy for patients with choriocarcinoma.

Saltiness enhancement by the characteristic flavor of dried bonito stock

There is a pressing need for the development of ways of preparing palatable salt-reduced foods to reduce the salt intake of the Japanese population. The salt-reducing effect of the characteristic flavors other than umami of dried bonito stock, which is widely used in everyday Japanese food, was examined by sensory evaluation. In the 1st sensory evaluation, the effect was evaluated in a model solution. The saltiness of 0.80% NaCl solution was equivalent to that of 0.12% monosodium glutamate (MSG) solution containing 0.81% NaCl and dried bonito stock containing 0.68% NaCl. Saltiness enhancement could not be found when MSG solution was used, but was found with 6% dried bonito stock. The 2nd evaluation examined whether the effect was valid for 2 everyday Japanese foods--traditional Japanese clear soup (sumashi-jiru) and steamed egg custard (tamagodoufu). Although enhancement of saltiness by dried bonito stock could not be clearly demonstrated in the soup, a change in NaCl concentration within 15% did not affect the palatability of the soup. However, dried bonito stock not only enhanced the saltiness but also improved the palatability of steamed egg custard. These findings are expected to be useful for improving the palatability of salt-reduced food.

Induction of gene encoding FABP4 in Pten-null keratinocytes

Keratinocyte-specific Pten-null mice revealed distinct phenotypes, including epidermal and sebaceous gland hyperplasia. To determine the candidate genes that contribute to their phenotypes, we analyzed a comprehensive gene expression of Pten-null keratinocytes using microarray technology. Consequently, it was demonstrated that the most induced gene was adipocyte-specific fatty acid-binding protein (FABP4). Collectively, it is conceivable that the FABP4 pathway mediates the sebaceous gland hyperplasia in keratinocyte-specific Pten-null mice.

Accuracy and reliability of continuous blood glucose monitor in post-surgical patients

BACKGROUND

The STG-22 is the only continuous blood glucose monitoring system currently available. The aim of this study is to determine the accuracy and reliability of the STG-22 for continuously monitoring blood glucose level in post-surgical patients.

METHODS

Fifty patients scheduled for routine surgery were studied in surgical intensive care unit (ICU) of a university hospital. After admission to the ICU, the STG-22 was connected to the patients. An attending physician obtained blood samples from a radial arterial catheter. Blood glucose level was measured using the ABL800FLEX immediately after blood collection at 0, 4, 8, and 16 h post-admission to the ICU (total of 200 blood glucose values).

RESULTS

The correlation coefficient (R2) was 0.96. In the Clarke error grid, 100% of the paired measurements were in the clinically acceptable zone A and B. The Bland and Altman analysis showed that bias+/-limits of agreement (percent error) were 0.04(0.7)+/-0.35(6.3) mmol (mg/dl) (7%), -0.11(-2)+/-1.22(22) (15%) and -0.33(-6)+/-1.28(23) (10%) in hypoglycemia (<70(3.89) mmol (mg/dl), normoglycemia (3.89(70)-10(180) mmol (mg/dl), and hyperglycemia (>10(180) mmol (mg/dl), respectively.

CONCLUSIONS

The STG-22 can be used for measuring blood glucose level continuously and measurement results are consistent with intermittent measurement (percentage error within 15%). Therefore, the STG-22 is a useful device for monitoring in blood glucose level in the ICU for 16 h.

Bleeding time prolonged by daily low-dose aspirin is shortened by one medium dose aspirin

BACKGROUND

In planning surgery, a low-dose aspirin regimen for prevention of thrombotic events is often discontinued in order to avoid the risk of excessive bleeding during surgery. However, this procedure increases the risk from adverse thrombotic events. We propose a different method, which may normalize the prolonged bleeding time caused by low-dose aspirin. We verified the effectiveness of this method in healthy volunteers.

METHODS

Volunteers with bleeding time prolonged by taking 81 mg of aspirin a day for a period of 1 week were randomly divided into two groups. The test group of 18 volunteers received a dose of 660 mg of aspirin, while the control group of 16 received placebo. Bleeding time and maximum platelet activity were then evaluated.

RESULTS

Before 660 mg of aspirin or placebo, bleeding time was prolonged: in the aspirin group from 3.1 +/- 0.7 to 6.1 +/- 1.4 min (n=18), and in the placebo group from 2.9 +/- 0.9 to 6.1 +/- 1.5 min (n=16). This prolongation was significant in both groups at the P<0.01 level. In the test group, bleeding time was shortened to 4.5 +/- 1.3 min (P<0.01), which is in the normal range, while it remained prolonged in the control group (6.0 +/- 1.2 min). Platelet activity, on the other hand, was suppressed in both groups.

CONCLUSION

We conclude that 660 mg of aspirin effectively shortens the bleeding time prolonged by daily low-dose (81 mg) aspirin.

Pten deficiency in melanocytes results in resistance to hair graying and susceptibility to carcinogen-induced melanomagenesis

Phosphate and tensin homologue deleted on chromosome 10 (PTEN) is a tumor suppressor gene inactivated in numerous sporadic cancers, including melanomas. To analyze Pten functions in melanocytes, we used the Cre-loxP system to delete Pten specifically in murine pigment-producing cells and generated DctCrePten(flox/flox) mice. Half of DctCrePten(flox/flox) mice died shortly after birth with enlargements of the cerebral cortex and hippocampus. Melanocytes were increased in the dermis of perinatal DctCrePten(flox/flox) mice. When the mutants were subjected to repeated depilations, melanocyte stem cells in the bulge of the hair follicle resisted exhaustion and the mice were protected against hair graying. Although spontaneous melanomas did not form in DctCrePten(flox/flox) mice, large nevi and melanomas developed after carcinogen exposure. DctCrePten(flox/flox) melanocytes were increased in size and exhibited heightened activation of Akt and extracellular signal-regulated kinases, increased expression of Bcl-2, and decreased expression of p27(Kip1). Our results show that Pten is important for the maintenance of melanocyte stem cells and the suppression of melanomagenesis.