Search tips
Search criteria

Results 1-3 (3)

Clipboard (0)

Select a Filter Below

more »
Year of Publication
Document Types
Soluble adenylyl cyclase (sAC) is an enzyme that generates cyclic adenosine monophosphate (cAMP), a signaling molecule involved in regulating melanocyte differentiation, proliferation and melanogenesis. R21, a mouse monoclonal antibody against sAC, shows a pattern of pan nuclear staining in lentigo maligna showing possible utility for diagnosis and for margin assessment.
31 re-excision specimens for lentigo maligna were evaluated for R21 expression using a previously published protocol. In addition, a prospective analysis of 123 cases including 41 lentigo malignas, 30 non-lentigo maligna type melanomas, 38 lentigos and 44 benign nevi were evaluated using a modified stringent protocol that eliminates non-melanocyte staining.
The sensitivity of nuclear staining with R21 in lentigo maligna was 87.8%. Nuclear expression of sAC was observed in 40% of other melanomas and in only 2.3% of the benign nevi. R21 did not stain nuclei of resting melanocytes but nuclear staining was observed in 28.9% of melanocytic hyperplasias. R21 staining facilitated extent of the lesion in resection margins. In cases examined under the less stringent conditions interpretation can be facilitated by comparing R21 and Mart1/Melan A staining. Greater than 9 pan nuclear staining melanocytes within one high power field along with a pan nuclear sAC/melan A ratio >0.5 was consistent with a positive margin while five or less pan nuclear staining melanocytes along with a sAC/melan A ratio of <0.3 constituted a negative margin.
R21 is a useful diagnostic adjunct in the diagnosis of lentigo maligna and can facilitate the evaluation of margins in re-excisions.
PMCID: PMC3732207  PMID: 23194049
2.  The correlation of TRPM1 (Melastatin) mRNA expression with microphthalmia-associated transcription factor (MITF) and other melanogenesis-related proteins in normal and pathological skin, hair follicles and melanocytic nevi 
Journal of cutaneous pathology  2010;37(Suppl 1):26-40.
Melastatin (TRPM1), a.k.a. transient receptor potential cation channel, subfamily M, member 1 (TRPM-1) regulates melanocyte differentiation and proliferation. TRPM1 is transcriptionally regulated by the essential melanocyte transcription factor MITF (microphthalmia-associated transcription factor). For the most part, MITF expression is preserved during melanoma progression, while TRPM1 mRNA expression decreases or is completely lost. The loss of TRPM1 is associated with melanomas that are more aggressive.
To assess the relationship between TRPM1 mRNA expression and the expression of MITF and nine other markers of melanocytes and melanin-related proteins by immunohistochemistry in normal skin, scars, hair follicles and ordinary melanocytic nevi.
Samples of normal skin (n = 102; from tumor excisions and plastic procedures), scars (n = 5; from re-excision specimens) and compound melanocytic nevi (n = 4) were evaluated for the presence of TRPM1 mRNA transcripts as detected by chromogenic in situ hybridization (CISH). Immunohistochemical techniques were used to detect melanin-related proteins including: MITF, S100 protein, Mart-1, tyrosinase, Mel5, HMB45, tyrosinase-related protein-1 (TRP1), TRP2 and α-melanocyte stimulating hormone (αMSH). The labeling index (LI) was defined as the number of intraepidermal cells expressing mRNA or protein per one hundred basal keratinocytes.
A wide range of LI was found for all markers (0–33 positive cells/100 keratinocytes). When these LI were compared, no significant differences in the expression of MITF, S100, Mart1, tyrosinase proteins and TRPM1 mRNA were identified. The LI for TRPM1 mRNA expression ranged from 74% of that for MITF to 86% for tyrosinase. The LI for TRP-1, TRP-2 and Mel5 was similar to that of TRPM1, while HMB-45 had a significantly lower LI than all other markers. TRPM1 mRNA correlated most tightly with MITF and tyrosinase expression (r = 0.81 and 0.68, respectively, both p = 0.0001). Likewise, the strongest correlation among all the melanin-related proteins existed between tyrosinase and MITF (r = 0.79, p = 0.0001). There was variable expression of melanin-related proteins when LI were analyzed by anatomic site, patient age, extent of sun-damage and proximity to a melanocytic tumor. Anogenital skin showed the highest and acral skin the lowest LI for TRPM1, MITF, S100 protein, Tyrosinase, Mel5 and HMB45. Advanced age (>60 years) was associated with decreased TRPM1 expression. Sun-damaged skin exhibited significantly increased LI as measured by MITF, S100 protein, Mart1, tyrosinase and HMB-45, but no differences for TRPM1. However, the MITF-TRPM1 differential (i.e. MITF LI-TRPM1 LI = MITF+TRPM1 – melanocytes) was significantly increased in site-matched skin (4.6 ± 4.4 vs. 1.5 ± 2.5, p = 0.01). There was a suggestion of reduced LI in normal skin in the proximity of melanoma (from melanoma re-excision specimens) for S100, HMB45 and TRPM1 mRNA. TRPM1 LI was significantly decreased in scars compared to normal skin (5.6 ± 1.4 vs. 9.7 ± 4.3, p = 0.02), this was reflected in an increase in the MITF-TRPM1 differential (9.6 ± 7.5 vs. 3.2 ± 3.1, p = 0.0001). MITF LI were consistently higher than MSLN LI at all levels of the hair follicle; notably, MITF was expressed by isthmic-bulge cells. In ordinary melanocytic nevi, MITF and TRPM1 expression decreased with melanocyte descent: there was more signal for both markers in superficial epithelioid type A melanocytes than deeper type C melanocytes.
By CISH, TRPM1 mRNA expression is specific for melanocytes and strongly associated with MITF and tyrosinase expression, the latter implicating a mature melanocyte phenotype. However, in normal skin, TRPM1 mRNA expression appears to be dynamic, labeling most but not all melanocytes, with variable expression ostensibly related to local environmental factors.
PMCID: PMC2882198  PMID: 20482673
3.  Cotransplanted Bone Marrow Derived Mesenchymal Stem Cells (MSC) Enhanced Engraftment of Hematopoietic Stem Cells in a MSC-dose Dependent Manner in NOD/SCID Mice 
Journal of Korean Medical Science  2006;21(6):1000-1004.
Transplantation of marrow-derived mesenchymal stem cells (MSCs), expanded by culture in addition to whole bone marrow, has been shown to enhance engraftment of human hematopoietic stem cells (HSCs). Our hypothesis was that there might be an optimum ratio range that could enhance engraftment. We examined the percent donor chimerism according to the ratio of HSCs to MSCs in non-obese diabetic/severe combined immunodeficiency (NOD/SCID) mice. We tested a series of ratios of co-transplanted CD34+-selected bone marrow cells, and marrow-derived MSCs into sublethally irradiated NOD/SCID mice. In all experiments, 1×105 bone marrow derived human CD34+ cells were administered to each mouse and human MSCs from different donors were infused concomitantly. We repeated the procedure three times and evaluated engraftment with flow cytometry four weeks after each transplantation. Serial ratios of HSCs to MSCs were 1:0, 1:1, 1:2 and 1:4, in the first experiment, 1:0, 1:1, 1:2, 1:4 and 1:8 in the second and 1:0, 1:1, 1:4, 1:8 and 1:16 in the third. Cotransplantation of HSCs and MSCs enhanced engraftment as the dose of MSCs increased. Our results suggest that the optimal ratio of HSCs and MSCs for cotransplantation might be in the range of 1:8-1:16; whereas, an excessive dose of MSCs might decrease engraftment efficiency.
PMCID: PMC2721918  PMID: 17179676
Hematopoietic Stem Cells; Mesenchymal Stem Cells; Transplantation; Mice, SCID; Engraftment

Results 1-3 (3)