Merkel Cell Carcinoma In Situ: No More Serendipity?

ABSTRACT: A 50-year-old man, with a history of extensive sun exposure and multiple previous non-melanoma skin cancers, presented with an asymptomatic 8-× 10-millimeter scaly, skin-colored papule on his right shoulder. Subsequent biopsy and excision revealed epidermal hyperplasia containing large atypical basaloid cells with pagetoid spread. Immunoperoxidase staining for cytokeratin-20 demonstrated a focal perinuclear dot-like pattern, and after excluding other in situ entities, a diagnosis of Merkel cell carcinoma In Situ (MCCIS) was rendered. MCCIS is a very rare entity. Although approximately 18% of Merkel cell carcinomas have epidermal involvement, currently only 17 cases of MCCIS have been reported, of which only 7 had no associated neoplasm. Previously, MCCIS was considered a serendipitous or incidental finding, as most cases co-existed with squamous cell carcinoma in situ. This case is unique in that it was not associated with a squamous lesion, and in addition, the pagetoid spread was unusual and has only occasionally been described. As such, MCCIS should be added to list of in situ epidermal lesions with pagetoid spread.

Rho GTPases control specific cytoskeleton-dependent functions of hematopoietic stem cells.

The Rho family of guanosine triphosphatases (GTPases) is composed of members of the Ras superfamily of proteins. They are GTP-bound molecules with a modest intrinsic GTPase activity that can be accelerated upon activation/localization of specialized guanine nucleotide exchange factors. Members of this family act as molecular switches and are required for coordinated cytoskeletal rearrangements that are crucial in a set of specialized functions of mammalian stem cells. These functions include self-renewal, adhesion, and migration. Mouse gene-targeting studies have provided convincing evidence of the indispensable and dispensable roles of individual members of the Rho GTPase family and the putative upstream and downstream mediators in stem cell-specific functions. The role of Rho GTPases and related signaling pathways previously seen in other cell types and organisms have been confirmed in mammalian hematopoietic stem cells (HSCs), and new signaling pathways and unexpected functions unique to HSCs have been identified and dissected. This review summarizes our current understanding of the role of Rho family of GTPases on HSC and progenitor activity through cytoskeleton-mediated signaling pathways, providing insight about relevant signaling pathways that regulate mammalian stem cell self-renewal, adhesion, and migration.

Vav3 collaborates with p190-BCR-ABL in lymphoid progenitor leukemogenesis, proliferation, and survival.

Despite the introduction of tyrosine kinase inhibitor therapy, the prognosis for p190-BCR-ABL(+) acute lymphoblastic leukemia remains poor. In the present study, we present the cellular and molecular roles of the Rho GTPase guanine nucleotide exchange factor Vav in lymphoid leukemogenesis and explore the roles of Vav proteins in BCR-ABL-dependent signaling. We show that genetic deficiency of the guanine nucleotide exchange factor Vav3 delays leukemogenesis by p190-BCR-ABL and phenocopies the effect of Rac2 deficiency, a downstream effector of Vav3. Compensatory up-regulation of expression and activation of Vav3 in Vav1/Vav2-deficient B-cell progenitors increases the transformation ability of p190-BCR-ABL. Vav3 deficiency induces apoptosis of murine and human leukemic lymphoid progenitors, decreases the activation of Rho GTPase family members and p21-activated kinase, and is associated with increased Bad phosphorylation and up-regulation of Bax, Bak, and Bik. Finally, Vav3 activation only partly depends on ABL TK activity, and Vav3 deficiency collaborates with tyrosine kinase inhibitors to inhibit CrkL activation and impair leukemogenesis in vitro and in vivo. We conclude that Vav3 represents a novel specific molecular leukemic effector for multitarget therapy in p190-BCR-ABL-expressing acute lymphoblastic leukemia.

Morphea and its variants and the "floating sign"-an additional finding in morphea.

We report 2 patients with typical clinical findings of circumscribed morphea who on histopathologic examinations had histiocytes ("floating sign") surrounding individual collagen fibers in the dermis in addition to the key histologic findings of morphea. To our knowledge, there are no previous reports in the medical literature of such a phenomenon. Histopathological findings in idiopathic morphea and morphea-like conditions are reviewed.

Insulin-like growth factor binding protein-3 mediates vascular repair by enhancing nitric oxide generation.

RATIONALE: Insulin-like growth factor binding protein (IGFBP)-3 modulates vascular development by regulating endothelial progenitor cell (EPC) behavior, specifically stimulating EPC cell migration. This study was undertaken to investigate the mechanism of IGFBP-3 effects on EPC function and how IGFBP-3 mediates cytoprotection following vascular injury. OBJECTIVE: To examine the mechanism of IGFBP-3-mediated repair following vascular injury. METHODS AND RESULTS: We used 2 complementary vascular injury models: laser occlusion of retinal vessels in adult green fluorescent protein (GFP) chimeric mice and oxygen-induced retinopathy in mouse pups. Intravitreal injection of IGFBP-3-expressing plasmid into lasered GFP chimeric mice stimulated homing of EPCs, whereas reversing ischemia induced increases in macrophage infiltration. IGFBP-3 also reduced the retinal ceramide/sphingomyelin ratio that was increased following laser injury. In the OIR model, IGFBP-3 prevented cell death of resident vascular endothelial cells and EPCs, while simultaneously increasing astrocytic ensheathment of vessels. For EPCs to orchestrate repair, these cells must migrate into ischemic tissue. This migratory ability is mediated, in part, by endogenous NO generation. Thus, we asked whether the migratory effects of IGFBP-3 were attributable to stimulation of NO generation. IGFBP-3 increased endothelial NO synthase expression in human EPCs leading to NO generation. IGFBP-3 exposure also led to the redistribution of vasodilator-stimulated phosphoprotein, an NO regulated protein critical for cell migration. IGFBP-3-mediated NO generation required high-density lipoprotein receptor activation and stimulation of phosphatidylinositol 3-kinase/Akt pathway. CONCLUSION: These studies support consideration of IGFBP-3 as a novel agent to restore the function of injured vasculature and restore NO generation.

Novel 16-minute technique for evaluating melanoma resection margins during Mohs surgery.

BACKGROUND: Immunohistochemistry (IHC) applied to Mohs micrographic surgery (MMS) is time consuming and labor intensive, and the variability of staining quality has prevented its widespread use in clinical practice. OBJECTIVE: To investigate the readability of immunostains processed by a novel automated 16-minute technique used for evaluation of frozen sections prepared during MMS for melanoma. METHODS: A rapid automated instrument that performs MART-1 (melanoma antigen recognized by T cells) immunostains in 16 minutes was used to stain frozen sections and was compared with MART-1 stains of paraffin (permanent) sections, hematoxylin-eosin (H&E) stains of frozen and permanent sections from the positive or negative control specimens of the Mohs layers for melanoma. A total of 480 interpretations from 48 sections (4 types of stains for each specimen, 12 specimens read by 10 interpreters) were analyzed via blinded examination by 5 dermatopathologists and 5 Mohs surgeons at two institutions. A scoring system was used to assess the readability of each slide. Analysis of variance was used for statistical analysis. RESULTS: In terms of clarity of interpreting melanoma sections, the 16-minute MART-1 IHC of frozen sections is equivalent to the standard MART-1 of permanent sections. The 16-minute MART-1 sections are also significantly easier to interpret than permanent sections stained with H&E for both the dermatopathologists and Mohs surgeons (P < .05). LIMITATIONS: The study represents data collected from only two institutions in the United States. CONCLUSION: The rapid-stained frozen IHC sections are significantly easier to interpret than the "gold standard" permanent sections stained with H&E. This technology facilitates the rapid interpretation of melanoma in frozen sections.

The operative management of melanoma: where does Mohs surgery fit in?

BACKGROUND: Melanoma is a life-threatening malignancy. Surgery is the primary management for melanoma, and management guidelines have evolved gradually over a century from radical surgery with lymph node dissection to conservative margin surgery. There are specific rationales and problems with Mohs micrographic (MMS) surgery for managing melanoma. OBJECTIVE: To review the literature for the surgical management of melanoma and to understand where MMS fits in this spectrum of management options. CONCLUSIONS: MMS should be considered as an option for melanoma surgery, especially when the tumor is found in photodamaged skin. Further randomized prospective clinical trials are needed to select the best therapeutic approach for the treatment of melanoma. Until then, careful margin control is the key for successful tumor removal whether it is standard excision, staged excision, or MMS.

Treatment of squamous cell carcinoma in situ: a review.

BACKGROUND: Squamous cell carcinoma in situ (SCCIS) is thought to be a precursor to squamous cell carcinoma. It should be treated before invasive cancer develops, especially in transplant recipients, who may develop more aggressive skin cancers. Treatment can involve surgical and nonsurgical methods. OBJECTIVE To review the evidence available in the English medical literature for different treatment options of SCCIS on nongenital skin and evaluate the efficacy of each option. METHODS AND MATERIALS: A Pubmed search of articles describing the treatment of SCCIS was conducted. Keywords were "treatment," "Bowen's disease," and "squamous cell carcinoma in situ." Articles describing the use of surgical excision, curettage and electrodesiccation, cryotherapy, 5-fluorouracil, imiquimod, radiation, photodynamic therapy, lasers, and rarer methods were reviewed. RESULTS: No single treatment can be said to be superior for any one situation. Most studies are small, limiting the power of each. Further studies are needed to clarify optimal treatment protocols for nonsurgical methods such as cryotherapy, photodynamic therapy, and topical chemotherapy. CONCLUSION: There are many methods available to treat SCCIS. Physicians should consider each patient's situation while keeping in mind that treatment protocols have not been fully defined for most options. The authors have indicated no significant interest with commercial supporters.

Preoperative methicillin-resistant Staphylococcus aureus screening in Mohs surgery appears to decrease postoperative infections.

BACKGROUND: Colonization with methicillin-resistant Staphylococcus aureus (MRSA) places patients at risk for postoperative MRSA wound infections. OBJECTIVE: To determine the effect of a decontamination and prophylaxis protocol on postoperative MRSA wound infections in patients with nasal MRSA. METHODS & MATERIALS: Wound cultures over a 23-month period were reviewed before and 11 months after implementation of a screening and decontamination protocol. After preoperative MRSA screening with nasal swabs, carriers were instructed to use intranasal mupirocin for 5 to 7 days before surgery and 5 to 7 days of trimethoprim-sulfamethoxazole starting the day before surgery. RESULTS: During the 23 months before prescreening evaluation, we performed 3,633 Mohs surgical cases, and 12 postoperative MRSA wound infections (0.3%) occurred. Subsequently, 963 patients underwent screening for MRSA, and 23 MRSA carriers were identified (2.4%). Of the 22 who underwent the decontamination and treatment protocol, none developed postoperative wound infections. One MRSA carrier did not receive preoperative treatment and subsequently developed a MRSA wound infection. There were no other MRSA infections. CONCLUSION: Preoperative MRSA screening and implementation of a decontamination protocol appears to decrease postoperative MRSA wound infections after Mohs surgery. Although an interesting observation, controlled studies of clinical and cost effectiveness are required before general implementation. The authors have indicated no significant interest with commercial supporters.

Labeling of stem cells with monocrystalline iron oxide for tracking and localization by magnetic resonance imaging.

Precise localization of exogenously delivered stem cells is critical to our understanding of their reparative response. Our current inability to determine the exact location of small numbers of cells may hinder optimal development of these cells for clinical use. We describe a method using magnetic resonance imaging to track and localize small numbers of stem cells following transplantation. Endothelial progenitor cells (EPC) were labeled with monocrystalline iron oxide nanoparticles (MIONs) which neither adversely altered their viability nor their ability to migrate in vitro and allowed successful detection of limited numbers of these cells in muscle. MION-labeled stem cells were also injected into the vitreous cavity of mice undergoing the model of choroidal neovascularization, laser rupture of Bruch's membrane. Migration of the MION-labeled cells from the injection site towards the laser burns was visualized by MRI. In conclusion, MION labeling of EPC provides a non-invasive means to define the location of small numbers of these cells. Localization of these cells following injection is critical to their optimization for therapy.

High-throughput identification of clinically important bacterial pathogens using DNA microarray.

Rapid and accurate detection of pathogenic bacteria is important for the treatment of patients with suitable antibiotics. Here we report the development of a diagnostic DNA microarray for the high-throughput identification of 39 pathogenic bacteria selected based on their high prevalence rate and/or difficulty of cultivation. The 23S ribosomal DNA and 16S-23S rDNA intergenic spacer region were used as target DNAs for pathogen detection. Universal- and species-specific probes were designed based on the unique and common sites within the target DNA sequences. New target DNA sequences were determined for the detection of 19 bacterial pathogens. The usefulness of the designed probes was validated using 39 reference bacteria and also with 515 clinical isolates from various clinical samples including blood, stool, pus, sputum, urine and cerebrospinal fluid. The DNA microarray developed in this study allowed efficient detection of bacterial pathogens with the specificities of 100%. The sensitivities were 100% as well except for the two pathogens, Enterobacter cloacae (75%) and Enterococcus faecium (85%). These results suggest that the DNA microarray-based assay developed in this study outperforms current diagnostic systems with respect to sensitivity, specificity, and high-throughput detection, and thus should be useful in pathogen diagnosis in the clinical setting.

Treatment of severe alopecia areata with intralesional steroid injections.

BACKGROUND: Treatment of alopecia areata with intralesional steroid injection is generally recommended for people who have less than 50% scalp involvement. In a specialized hair loss clinic, the authors successfully treated patients with extensive alopecia areata (over 50% but under 99%) with intralesional corticosteroid injections. OBSERVATIONS: A review of patients with extensive alopecia areata was done. Six out of 10 patients responded to treatment with intralesional triamcinolone acetonide. In comparison to the non-responders, the responders tended to have exclamation mark hairs and a positive hair pull test at their initial physical examination, and exhibited improvement during the initial months of treatment. Complications were negligible, with mild reversible atrophy in three patients. The treatment was well tolerated and, in some patients, pain was minimized by use of a topical anesthetic agent applied under occlusion prior to the visit. CONCLUSION: Intralesional triamcinolone acetonide is a safe and effective treatment for patients with extensive alopecia areata. Patients with exclamation point hairs and a positive hair pull test may be more likely to respond.

Ischemic vascular damage can be repaired by healthy, but not diabetic, endothelial progenitor cells.

Endothelial precursor cells (EPCs) play a key role in vascular repair and maintenance, and their function is impeded in diabetes. We previously demonstrated that EPCs isolated from diabetic patients have a profound inability to migrate in vitro. We asked whether EPCs from normal individuals are better able to repopulate degenerate (acellular) retinal capillaries in chronic (diabetes) and acute (ischemia/reperfusion [I/R] injury and neonatal oxygen-induced retinopathy [OIR]) animal models of ocular vascular damage. Streptozotocin-induced diabetic mice, spontaneously diabetic BBZDR/Wor rats, adult mice with I/R injury, or neonatal mice with OIR were injected within the vitreous or the systemic circulation with fluorescently labeled CD34(+) cells from either diabetic patients or age- and sex-matched healthy control subjects. At specific times after administering the cells, the degree of vascular repair of the acellular capillaries was evaluated immunohistologically and quantitated. In all four models, healthy human (hu)CD34(+) cells attached and assimilated into vasculature, whereas cells from diabetic donors uniformly were unable to integrate into damaged vasculature. These studies demonstrate that healthy huCD34(+) cells can effectively repair injured retina and that there is defective repair of vasculature in patients with diabetes. Defective EPCs may be amenable to pharmacological manipulation and restoration of the cells' natural robust reparative function.

Connexins: Intercellular Signal Transmitters in Lymphohematopoietic Tissues.

Life-long hematopoietic demands are met by a pool of hematopoietic stem cells (HSC) with self-renewal and multipotential differentiation ability. Humoral and paracrine signals from the bone marrow (BM) hematopoietic microenvironment control HSC activity. Cell-to-cell communication through connexin (Cx) containing gap junctions (GJs) allows pluricellular coordination and synchronization through transfer of small molecules with messenger activity. Hematopoietic and surrounding nonhematopoietic cells communicate each other through GJs, which regulate fetal and postnatal HSC content and function in hematopoietic tissues. Traffic of HSC between peripheral blood and BM is also dependent on Cx proteins. Cx mutations are associated with human disease and hematopoietic dysfunction and Cx signaling may represent a target for therapeutic intervention. In this review, we illustrate and highlight the importance of Cxs in the regulation of hematopoietic homeostasis under normal and pathological conditions.

Vasculopathy-associated hyperangiotensinemia mobilizes haematopoietic stem cells/progenitors through endothelial AT2R and cytoskeletal dysregulation.

Patients with organ failure of vascular origin have increased circulating haematopoietic stem cells and progenitors (HSC/P). Plasma levels of angiotensin II (Ang-II), are commonly increased in vasculopathies. Hyperangiotensinemia results in activation of a very distinct Ang-II receptor set, Rho family GTPase members, and actin in bone marrow endothelial cells (BMEC) and HSC/P, which results in decreased membrane integrin activation in both BMEC and HSC/P, and in HSC/P de-adhesion and mobilization. The Ang-II effect can be reversed pharmacologically and genetically by inhibiting Ang-II production or signalling through BMEC AT2R, HSCP Ang-II receptor type 1 (AT1R)/AT2R or HSC/P RhoA, but not by interfering with other vascular tone mediators. Hyperangiotensinemia and high counts of circulating HSC/P seen in sickle cell disease (SCD) as a result of vascular damage, is significantly decreased by Ang-II inhibitors. Our data define for the first time the role of Ang-II HSC/P traffic regulation and redefine the haematopoietic consequences of anti-angiotensin therapy in SCD.

Increasing vancomycin susceptibility in vancomycin resistant enterococci by vanH promoter and ddl transformation.

OBJECTIVES: In vancomycin resistant enterococci (VRE) the vanHAXYZ genes encode a new pathway of enzymes to produce d-alanyl-d-lactate. We investigated the effect of vanH promoter and ddl gene transformation on vancomycin susceptibility in a vanA phenotype of Enterococcus faecalis. METHODS: To construct plasmid pJW1, the vanH promoter was cloned to plasmid pAM401. Plasmid pJW2 was constructed by cloning the ddl gene into pAM401. To construct pJW3, the ddl gene was ligated downstream of the vanH promoter of the plasmid pJW1. The competent VRE was transformed with pJW1, pJW2 and pJW3 using electroporation. The minimal inhibitory concentration (MIC) of vancomycin for VRE and transformed E. faecalis was determined using the broth dilution method. The expression of the vanA and ddl gene of VRE and transformed E. faecalis was evaluated by RT PCR. RESULTS: The transformation of the vanH promoter reduced the vancomycin MIC of VRE. In VRE and transformed E. faecalis, the vanA and ddl genes were expressed. CONCLUSIONS: This study presents a way of altering high-level vancomycin resistance with gene transformation in enterococci. In the future, development of an effective gene delivery system will contribute to the design of new modalities that will help overcome the limitations of antimicrobial therapy.

Clinical outcomes of tuberculosis in renal transplant recipients.

Tuberculosis (TB) is an important cause of morbidity and mortality in renal transplant recipients. Rifampin has a potent sterilizing activity, but it reduces the serum concentrations of the immunosuppressive agents. Moreover, the possible contribution made by mycobacterial infection to the incidence of graft rejection or renal dysfunction remains unclear. In this study, we investigated the recurrence of TB and graft survival duration according to rifampin usage, and we evaluated the factors that could influence the duration time until the recurrence of TB. Seventy-eight TB patients diagnosed after kidney transplantation were studied. Pulmonary TB was diagnosed in 26 of the 78 patients (33.3%), pleural TB in 23 (29.5%), combined pulmonary and pleural TB in 5 (6.4%), miliary TB in 19 (24.4%), and intestinal TB in 2 patients. In the pulmonary (pulmonary TB and pleural TB) TB group, no differences in graft survival and the TB free duration period were observed between the rifampin usage subgroup and the non- rifampin usage subgroup. In the extrapulmonary TB group, no difference was found in mean graft survival time between the rifampin usage subgroup and the non-rifampin usage subgroup, but the rifampin usage subgroup showed that the TB had a tendency to recur later than for the non-rifampin usage subgroup (87 +/- 8 vs. 44 +/- 7 months, respectively, p=0.30). The factor affecting the duration period until the recurrence of TB was the treatment duration (RR=0.761, p=0.030). This study suggests that rifampin does not affect graft survival in renal transplant recipients in whom immunosuppression is carefully monitored. Also, the study results indicate that rifampin may prevent a recurrence of extrapulmonary tuberculosis. Prolonged treatment appears to be appropriate for renal transplant recipients with TB.

Clinical manifestations and diagnosis of extrapulmonary tuberculosis.

Since the diagnosis of extrapulmonary tuberculosis (EPT) is largely depended on the physician's suspicion in respect of the disease, we believed that it would be worthwhile to scrutinize the clinical characteristics of EPT. Thus, here we present retrospectively evaluated clinical manifestations of patients who were diagnosed as EPT cases in a tertiary referral care hospital. Medical records of 312 patients, diagnosed as having EPT at Yongdong Severance hospital from January 1997 to December 1999, were reviewed retrospectively. In total 312 patients, 149 (47.8%) males and 163 (52.2%) females aged from 13 years to 87 years, were included into this study. The most common site of the involvement was pleura (35.6%). The patients complained of localized symptoms (72.4%) more frequently than systemic symptoms (52.2%). The most common symptom was pain at the infected site (48.1%). Leukocytosis, anemia, and elevated erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) were found in 12.8%, 50.3%, 79.3% and 63.1% of the patients, respectively. Twenty-four percent of the patients had underlying medical illnesses such as, diabetes mellitus or liver cirrhosis, or were over 60 years old. In 67.3% of patients, tuberculosis was suspected at the initial visit. However, tuberculosis was microbiologically proven in only 23.7% of the patients. The time interval from the symptom onset to the diagnosis varied, with the mean duration of the period 96 days. Pulmonary parenchymal abnormal lesions were found in 133 patients (42.6%) on chest radiographs. EPT has a wide spectrum of clinical manifestations, so it is difficult to diagnose it. Based on our studies, only 11.2% of the patients were confirmed as EPT. So it is important that the physician who first examines the patient should have a high degree of suspicion based on the chest radiography, localized or systemic symptoms and several laboratory parameters reviewed in this study.