Understanding the progression of melanocytic neoplasia using genomic analysis: from fields to cancer

Analysis of DNA copy number changes using comparative genomic hybridization in melanocytic neoplasms has revealed distinct patterns of chromosomal aberrations between benign melanocytic nevi and melanoma. Whereas the vast majority of melanoma expresses chromosomal aberrations, blue nevi, congenital nevi, and most Spitz nevi typically show no aberrations. A subset of Spitz nevi shows an isolated gain of chromosome 11p, an aberration pattern not observed in melanoma. These Spitz nevi frequently harbor mutations in the HRAS gene located on this chromosomal arm. Comparisons among melanoma types showed that melanomas of the palms, soles, and subungual sites can be distinguished by the presence of multiple gene amplifications that arise very early in their progression. About 50% of these amplifications are found at the cyclin D1 locus. By contrast, amplifications are significantly less frequent in other cutaneous melanoma types and if present arise late in progression. The frequent amplifications in melanomas on acral sites allowed the detection of single basal melanocytes with gene amplifications in the histologically normal appearing skin immediately adjacent to a melanoma. These "field cells" represent subtle melanoma in situ and are likely to represent minimal residual disease that can lead to local recurrences if not excised with safety margins. The high frequency of chromosomal aberrations in melanomas and their relative absence in nevi could indicate that melanocytes of melanomas went through telomeric crisis, whereas melanocytes in nevi did not. Such a scenario would suggest that replicative senescence is a tumor-suppressive mechanism in melanocytic neoplasia. It might also explain part of the phenomenon of regression commonly seen in melanoma. Genomic analysis is a powerful tool to obtain insight in the progression of melanocytic neoplasms with potential clinical applications for classification and detection of minimal residual melanoma.

Two cases of unusual acral melanocytic tumors: illustration of molecular cytogenetics as a diagnostic tool

The differential diagnosis between benign Spitz nevus and malignant melanoma may present considerable difficulties in some cases. Here we report 2 unusual melanocytic tumors with spitzoid features developing in acral sites of Japanese patients to illustrate the use of comparative genomic hybridization (CGH) to classify these lesions. Case 1 was a 12-mm-thick, >2 cm-diameter nodule on the sole of a 37-year-old man. Case 2 was a subungual tumor of the left index finger in a 13-year-old boy. CGH showed absence of chromosomal aberrations in case 1 and multiple aberrations in case 2, including focused amplification as previously described in acral melanomas. Case 1 was free of disease after 2.5 years of follow-up, whereas case 2 developed lymph node metastasis. We conclude that molecular techniques such as CGH can be of diagnostic help in the classification of histologically ambiguous lesions.

Molecular cytogenetics as a diagnostic tool for typing melanocytic tumors

The melanocyte can give rise to a variety of both benign and malignant lesions that differ in their clinical and histopathological appearance. It is likely that genetic changes underlie this phenotypic diversity. Comparative genomic hybridization (CGH) is a genome-wide scanning technique that permits the measurement of copy number aberrations in archival tumors. Using CGH, we have demonstrated significant differences in the frequency of chromosomal aberrations in primary cutaneous melanomas and Spitz nevi. Whereas the majority of melanomas have aberrations frequently involving chromosomes 9, 10, 7, and 6, most Spitz nevi do not show aberrations. However, a small subset of Spitz nevi show an isolated gain of the short arm of chromosome 11p. As this aberration has not been observed in melanomas, the measurement of chromosomal aberrations should be further evaluated as a diagnostic tool for ambiguous melanocytic tumors.

A full-coverage, high-resolution human chromosome 22 genomic microarray for clinical and research applications

We have constructed the first comprehensive microarray representing a human chromosome for analysis of DNA copy number variation. This chromosome 22 array covers 34.7 Mb, representing 1.1% of the genome, with an average resolution of 75 kb. To demonstrate the utility of the array, we have applied it to profile acral melanoma, dermatofibrosarcoma, DiGeorge syndrome and neurofibromatosis 2. We accurately diagnosed homozygous/heterozygous deletions, amplifications/gains, IGLV/IGLC locus instability, and breakpoints of an imbalanced translocation. We further identified the 14-3-3 eta isoform as a candidate tumor suppressor in glioblastoma. Two significant methodological advances in array construction were also developed and validated. These include a strictly sequence defined, repeat-free, and non-redundant strategy for array preparation. This approach allows an increase in array resolution and analysis of any locus; disregarding common repeats, genomic clone availability and sequence redundancy. In addition, we report that the application of phi29 DNA polymerase is advantageous in microarray preparation. A broad spectrum of issues in medical research and diagnostics can be approached using the array. This well annotated and gene-rich autosome contains numerous uncharacterized disease genes. It is therefore crucial to associate these genes to specific 22q-related conditions and this array will be instrumental towards this goal. Furthermore, comprehensive epigenetic profiling of 22q-located genes and high-resolution analysis of replication timing across the entire chromosome can be studied using our array.

Genetic changes in neoplasms arising in congenital melanocytic nevi: differences between nodular proliferations and melanomas

Large congenital melanocytic nevi (CMN) are at an increased risk of developing melanoma. Several forms of secondary proliferations can arise in congenital nevi on rare occasions. Although some of these closely resemble melanoma both clinically and histologically, metastasis is rare. We used comparative genomic hybridization to analyze chromosomal aberrations in different types of proliferations arising in CMN and compared them to typical congenital nevi, clear-cut melanomas arising in congenital nevi, as well as primary cutaneous melanomas that were not associated with a CMN. Cases of CMN and CMN with secondary proliferations were assigned to six groups according to the predominant histological pattern: group I, bland congenital nevi (n = 6); group II, congenital nevi with foci of increased cellularity (n = 4); group III, CMN with a proliferation simulating superficial spreading melanoma in situ (n = 3); group IV, CMN with a proliferation simulating nodular melanoma (n = 9); group V, proliferating neurocristic hamartoma (n = 1); and group VI, melanoma arising in congenital nevus (n = 6). No aberrations were found in groups I to III, whereas seven of nine cases of group IV, and one of one case of group V, showed aberrations. In group IV six of seven cases with aberrations (86%) showed numerical aberrations of whole chromosomes exclusively. This pattern differed significantly from the findings in melanoma that arose within CMN (n = 6), group VI, or independent of CMN (n = 122) in which only 5% showed numerical changes only. The single case in group V showed aberrations similar to melanoma. The finding of frequent numerical chromosomal aberrations in atypical nodular proliferations arising in CMN identifies these as clonal neoplasms with a genomic instability consistent with a mitotic spindle checkpoint defect. This difference compared to the aberration pattern found in melanoma might explain their more benign clinical behavior and may be of diagnostic value in ambiguous cases.

Cyclin D1 is a candidate oncogene in cutaneous melanoma

The retinoblastoma pathway has been implicated in melanoma; however, previous studies of one of the key components of this pathway, cyclin D1 (CD1), failed to find amplification of this gene in a large series of melanomas. We have recently shown that a particular subtype of melanoma, acral melanoma (AM), has frequent amplification of the CD1 locus. This suggested that CD1 might be important in AM and that it may also be important in other melanoma types, even though its copy number may not be altered. We compared CD1 gene copy number and protein expression in 137 invasive primary cutaneous melanomas (71 superficial spreading melanomas, 17 nodular melanomas, 19 lentigo maligna melanomas, 18 AMs, and 12 unclassifiable melanomas) using fluorescence in situ hybridization and immunohistochemistry. We found frequent amplification of CD1 in AM (44.4%) and occasional amplification in lentigo maligna melanoma (10.5%) and superficial spreading melanoma (5.6%). CD1 protein was overexpressed in all cases with amplifications and in an additional 20% of cases without amplification. We tested the importance of CD1 in cell growth in melanoma by using adenovirus-mediated antisense treatment targeted to CD1 in two melanoma cell lines, one with and the other without CD1 amplification and overexpression. Antisense mediated down-regulation of CD1 induced apoptosis in vitro and led to significant tumor shrinkage of melanoma xenografts in severe combined immunodeficient mice. However, it did not alter the growth of normal melanocytes. Together, these results suggest that CD1 may be an oncogene in melanoma and that targeting its expression may be therapeutically beneficial.

Persistent (recurrent) Spitz nevi: a histopathologic, immunohistochemical, and molecular pathologic study of 22 cases

This report describes 22 Spitz nevi that seemed to have been clinically removed but persisted and clinically recurred at the biopsy site. These were evaluated in terms of histopathology, immunohistochemistry, and molecular pathology using comparative genomic hybridization (CGH) and fluorescent in situ hybridization. One of these 22 lesions was originally reported as an atypical melanocytic proliferation with some features of a Spitz nevus and was included in the study set at an early stage but was later recognized as melanoma after metastasis to regional lymph nodes 3 years after the local recurrence. We noted four histopathologic patterns in the recurrent lesions: 1) a predominantly intraepidermal pattern resembling "pseudomelanoma" as seen in recurrent "common" melanocytic nevi, 2) a compound, mostly nested pattern above or within a scar that was nearly identical to the originally biopsied Spitz nevus, 3) a nodular growth pattern that closely simulated invasive melanoma, and 4) a desmoplastic pattern resembling an intradermal desmoplastic Spitz nevus. Although the majority of recurrent lesions exhibited asymmetry and pagetoid spread, the dermal component usually had a low mitotic rate and retained architectural and cytologic maturation, which allowed distinction from invasive melanoma. Except for the metastasizing melanoma, the immunostaining pattern with S-100 and HMB-45 was identical to that previously reported for Spitz nevi. Ki67 revealed a very low proliferation rate in all cases, including the melanoma. CGH performed in 10 cases yielded results consistent with Spitz nevi in eight cases. The remaining two cases showed CGH profiles more typical of melanoma, and one of these was the above-referenced case of melanoma, proven by metastasis. Although ancillary molecular techniques such as CGH are of great help in distinguishing these from melanoma, until such techniques become widely available we advocate complete but conservative excision of any recurrent Spitz nevus.

Genetic analysis of Pten and Ink4a/Arf interactions in the suppression of tumorigenesis in mice

Dual inactivation of PTEN and INK4a/ARF tumor suppressor genes is a common feature observed in a broad spectrum of human cancer types. To validate functional collaboration between these genes in tumor suppression, we examined the biological consequences of Pten and/or Ink4a/Arf deficiency in cells and mice. Relative to single mutant controls, Ink4a/Arf-/-Pten+/- mouse embryonic fibroblast cultures exhibited faster rates of growth in reduced serum, grew to higher saturation densities, produced more colonies upon low density seeding, and showed increased susceptibility to transformation by oncogenic H-Ras. Ink4a/Arf deficiency reduced tumor-free survival and shortened the latency of neoplasias associated with Pten heterozygosity, specifically pheochromocytoma, prostatic intraepithelial neoplasia, and endometrial hyperplasia. Compound mutant mice also exhibited an expanded spectrum of tumor types including melanoma and squamous cell carcinoma. Functional synergy between Ink4a/Arf and Pten manifested most prominently in the development of pheochromocytoma, prompting an analysis of genes and loci implicated in this rare human neoplasm. The classical pheochromocytoma genes Ret, Vhl, and Nf-1 remained intact, a finding consistent with the intersection of these genes with pathways engaged by Pten and Ink4a/Arf. Notably, conventional and array-comparative genomic hybridization revealed frequent loss of distal mouse chromosome 4 in a region syntenic to human chromosome 1p that is implicated in human pheochromocytoma. This study provides genetic evidence of collaboration between Pten and Ink4a/Arf in constraining the growth and oncogenic transformation of cultured cells and in suppressing a wide spectrum of tumors in vivo.

HDM2 protein overexpression, but not gene amplification, is related to tumorigenesis of cutaneous melanoma

We investigated the role of alterations of HDM2, the human homologue of murine mdm2, in the tumorigenesis and progression of cutaneous melanoma. A well-characterized cohort of 172 cases representing different points in the spectrum of melanocyte transformation (16 dysplastic nevi, 11 melanomas in situ, 107 invasive primaries, and 38 metastatic lesions), as well as 11 human melanoma cell lines were examined by immunohistochemistry and Western blotting for HDM2 protein expression, and by either Southern blotting (SB) or fluorescence in situ hybridization for HDM2 gene amplification. HDM2 overexpression, defined as >20% tumor cells showing nuclear immunoreactivity, was observed in 1 of 16 (6%) dysplastic nevi, 3 of 11 (27%) melanomas in situ, and 81 of 145 (56%) invasive primary and metastatic melanomas. Comparable frequencies of HDM2 overexpression were observed among invasive primary cases with differing tumor thicknesses as well as among the metastatic cases: 21 of 40 (53%) at < or =1.5 mm; 31 of 50 (62%) at 1.6-3.9 mm; 10 of 17 (58%) at >4 mm; and 19 of 38 (50%) metastases. HDM2 amplification was observed in 1 of 88 (1%) primary cases using fluorescence in situ hybridization, and in 0 of 12 (0%) metastatic cases that overexpressed HDM2 using SB. Melanoma cell lines expressed HDM2 protein, but there was no evidence of amplification by SB. Our data suggest that HDM2 protein overexpression is common in invasive and metastatic melanoma. Observing HDM2 overexpression in noninvasive melanoma suggests that expression of this oncogene may play an early role in melanocyte transformation. HDM2 amplification occurs infrequently, and other mechanisms that up-regulate HDM2 expression are under investigation.

Dual inactivation of RB and p53 pathways in RAS-induced melanomas

The frequent loss of both INK4a and ARF in melanoma raises the question of which INK4a-ARF gene product functions to suppress melanoma genesis in vivo. Moreover, the high incidence of INK4a-ARF inactivation in transformed melanocytes, along with the lack of p53 mutation, implies a cell type-specific role for INK4a-ARF that may not be complemented by other lesions of the RB and p53 pathways. A mouse model of cutaneous melanoma has been generated previously through the combined effects of INK4a(Delta2/3) deficiency (null for INK4a and ARF) and melanocyte-specific expression of activated RAS (tyrosinase-driven H-RAS(V12G), Tyr-RAS). In this study, we made use of this Tyr-RAS allele to determine whether activated RAS can cooperate with p53 loss in melanoma genesis, whether such melanomas are biologically comparable to those arising in INK4a(Delta2/3-/-) mice, and whether tumor-associated mutations emerge in the p16(INK4a)-RB pathway in such melanomas. Here, we report that p53 inactivation can cooperate with activated RAS to promote the development of cutaneous melanomas that are clinically indistinguishable from those arisen on the INK4a(Delta2/3) null background. Genomewide analysis of RAS-induced p53 mutant melanomas by comparative genomic hybridization and candidate gene surveys revealed alterations of key components governing RB-regulated G(1)/S transition, including c-Myc, cyclin D1, cdc25a, and p21(CIP1). Consistent with the profile of c-Myc dysregulation, the reintroduction of p16(INK4a) profoundly reduced the growth of Tyr-RAS INK4a(Delta2/3-/-) tumor cells but had no effect on tumor cells derived from Tyr-RAS p53(-/-) melanomas. Together, these data validate a role for p53 inactivation in melanomagenesis and suggest that both the RB and p53 pathways function to suppress melanocyte transformation in vivo in the mouse.

Mutations and copy number increase of HRAS in Spitz nevi with distinctive histopathological features

Spitz nevus is a benign melanocytic neoplasm that can be difficult or impossible to histologically distinguish from melanoma. We have recently described copy number increases of chromosome 11p in a subset of Spitz nevi. To study the molecular and histological features of this group, we studied 102 Spitz nevi for 11p copy number increases using fluorescence in situ hybridization (FISH) on tissue arrays. Copy number increases of at least threefold were found in 12 cases (11.8%) and involved the HRAS gene on chromosome 11p. Sequence analysis of HRAS showed frequent oncogenic mutations in cases with copy number increase (8/12 or 67%), contrasting with rare HRAS mutations in cases with normal HRAS copy numbers (1/21 or 5%, P: < 0.0001). Tumors with 11p copy number increases were larger, predominantly intradermal, had marked desmoplasia, characteristic cytological features, and had an infiltrating growth pattern. Proliferation rates in the majority of these cases were low to absent. HRAS activation by either mutation or copy number increase alone could explain several of the histological features that overlap with those of melanoma. We speculate that HRAS activation in the absence of co-operating additional genetic alterations drives the partially transformed melanocytes of these Spitz nevi into senescence or a stable growth arrest. Although there is no data suggesting that Spitz nevi with HRAS activation are at risk for progression to melanoma, future studies are warranted to assess their biological behavior more accurately.

Pericardial lipoma: ultrasound, computed tomography and magnetic resonance imaging findings

Primary tumours of the heart and pericardium are extremely rare. Cardiac lipomas account for only 10% of all primary cardiac tumours. A case of surgically proven pericardial lipoma demonstrated by ultrasound, CT and MRI is presented here.

Atrial myxoma demonstrated by cine gradient refocused echo magnetic resonance imaging

A case of atrial myxoma presenting with syncope evaluated by echocardiography and MRI is described. Cine gradient-echo MRI demonstrated atrial myxoma as a very low signal intensity mass indicating the presence of haemosiderin.

Gene amplifications characterize acral melanoma and permit the detection of occult tumor cells in the surrounding skin

Acral melanoma (AM) is commonly distinguished from superficial spreading melanoma (SSM), the most common type of melanoma, by its clinical presentation as well as its ethnic distribution. However, justification for such a distinction is controversial because of histological overlap and lack of prognostic significance. We analyzed chromosomal aberrations of 15 AMs and 15 SSMs that were comparable for tumor thickness and patient age, using comparative genomic hybridization. All AMs had at least one (mean, 2.0) gene amplification, significantly more than the SSMs, in which only 2 of 15 (13%) had one amplification each (P < 0.0001). At least 15 different genomic regions were amplified in AM. These involved small portions of chromosomal arms, sometimes including known oncogenes implicated in melanoma. The most frequently amplified regions in AMs occurred at 11q13 (47%), 22q11-13 (40%), and 5p15 (20%). Comparison of the amplification levels of invasive and noninvasive portions of the tumors using fluorescence in situ hybridization suggested that amplifications occurred before the formation of the invasive portion. The finding of amplifications of 11q13 in three of five additional cases of AM in situ further supports the notion that amplifications arise early in the progression of AM. Very significantly, we found isolated melanocytes with amplifications in the epidermis up to 3 mm beyond the histologically recognizable extent of the melanomas in 5 of 15 invasive AMs. In conclusion, our data show that AM is a distinct type of melanoma characterized by focused gene amplifications occurring early in tumorigenesis, and that malignant cells are present beyond the histologically detectable boundary, thereby revealing one mechanism of local recurrence.

Molecular cytogenetic analysis of Spitz nevi shows clear differences to melanoma

Spitz nevus is a benign neoplasm of melanocytes that can be difficult or impossible to distinguish from melanoma by clinical and histopathologic examination. We studied genomic DNA from 17 Spitz nevi by comparative genomic hybridization (CGH). Thirteen lesions showed no chromosomal aberrations, three cases had a gain involving the entire p-arm of chromosome 11, and one case showed a gain of chromosome 7q21-qter. Fluorescence in situ hybridization (FISH) on lesional tissue with a probe for the p-arm of chromosome 11 showed 6-10 p-arm signals per nucleus in those cases with a CGH-detected gain of chromosome 11p. One case with a normal CGH profile also showed increased copy number of 11p by FISH. Thus, the majority of Spitz nevi have a normal chromosomal complement at the level of CGH resolution; however some may contain gains, with 11p apparently being the most frequently involved location. These findings differ significantly from the previously reported changes in primary cutaneous melanoma, which show frequent deletions of chromosomes 9p (82%), 10q (63%), 6q (28%), and 8p (22%), as well as gains of chromosomes 7 (50%), 8 (34%), 6p (28%), 1q (25%) by CGH analysis. These clear differences in the location and frequencies of chromosomal aberrations in Spitz nevi and primary cutaneous melanomas could represent a basis for developing adjunctive techniques for refining accuracy in the difficult differential diagnosis of spitzoid melanocytic neoplasms.

Signet-ring cell formation in cutaneous neoplasms

BACKGROUND

Signet-ring cells are formed by intracytoplasmic accumulations of various substances that push the nucleus to the cellular border. Signet-ring cells in epithelial neoplasms are often regarded as evidence of adenocarcinoma.

OBJECTIVE

The study surveys the rare settings in which signet-ring cells are encountered in dermatopathologic specimens and investigates mechanisms of their formation.

METHODS

A total of 23 cutaneous tumors with a significant population of signet-ring cells were studied by immunohistochemistry and electron microscopy.

RESULTS

Signet-ring cells were found in a variety of cutaneous neoplasms, including primary cutaneous squamous and basal cell carcinoma and melanoma, as well as in metastatic adenocarcinoma. In all but the metastatic adenocarcinomas the vacuoles were periodic acid Schiff (PAS), PAS-digest, and colloidal iron negative. There was no staining of the vacuoles with antibodies against keratins and vimentin. Electron microscopy showed only empty spaces in all cases.

CONCLUSION

The signet-ring like appearance of the cells in most of these conditions is probably the result of coalescence of intracytoplasmic vacuoles and not accumulation of secretory products. Signet-ring formation is not specific for cellular lineage but can occur in a variety of cutaneous neoplasms, analogous to other cellular alterations as rhabdoid, granular, clear, spindle, and balloon cells and oncocytes.

[Pilomatrix carcinoma in an unusual location. Case report and review of the literature]

A 58-year-old man developed an extensive pilomatrical carcinoma in the left axilla. Clinically, a squamous cell carcinoma was suspected. Histological examination revealed the presence of proliferating basaloid cells with many atypical mitoses and mass necrosis infiltrating into the subcutaneous tissue. The tumor was removed by micrographic surgery with a 2 cm safety margin. Histological examination of 2 regional lymph nodes as well as further diagnostic procedures ruled out metastases. We review the clinical and histopathological differences between pilomatricoma and pilomatrical carcinoma, as well as the published cases of the malignant variant.

Paraneoplastic pemphigus treated with dexamethasone/ cyclophosphamide pulse therapy

Paraneoplastic pemphigus (PNP) is an autoimmune, mucocutaneous bullous disease associated with underlying malignancies. We report a patient with Waldenström's macroglobulinemia who developed clinical, histological and immunopathological features typical of PNP. The patient was treated twice with i.v. dexamethasone and cyclophosphamide pulse therapy (day 1: cyclophosphamide 500 mg i.v.; day 1-3: dexamethasone 100 mg i.v.) at 3-week intervals. Therapy was continued with oral cyclophosphamide (50 mg/d). Two weeks after initiation of treatment, significant improvement of the cutaneous and mucosal lesions was noted. The therapy also had beneficial effects on the macroglobulinemia in terms of a marked reduction of the IgM lambda serum level. Three months after the second pulse, severe stomatitis recurred but the patient rejected any further systemic therapy. The initial response of the usually recalcitrant mucosal and skin lesions of PNP makes dexamethasone/cyclophosphamide pulse therapy an interesting therapeutic option.

Eosinophilic globules in spitz nevi: no evidence for apoptosis

Eosinophilic globules are commonly found in Spitz nevi and can be of help in the differential diagnosis with melanoma. Despite their use as a diagnostic marker, there are conflicting concepts concerning the mechanism of the formation of these globules. Because pyknotic nuclei are often present in the cells surrounding the globules, many believe that apoptotic cell death of keratinocytes and melanocytes is an important mechanism in their formation. We studied nine Spitz nevi containing 21 eosinophilic globules for apoptotic cell death around and within Kamino bodies using the TUNEL method (TdT-mediated dUTP-x nick end-labeling method). In none of the cases were positive cells seen in the vicinity of the globules. Single apoptotic cells were found only sporadically in the melanocytes of the neoplasms (one to four per section) and were scattered throughout the entire lesion. The absence of apoptosis-specific labeled cells in the vicinity of eosinophilic globules and the rare occurrence of positive stained cells in other parts of the tumors makes apoptotic cell death unlikely to be relevant in the formation of eosinophilic globules.

Chromosomal gains and losses in primary cutaneous melanomas detected by comparative genomic hybridization

The analysis of genetic changes in primary cutaneous melanoma has been limited by the need for fixation for diagnostic purposes. However, comparative genomic hybridization is able to analyze such specimens. We have applied comparative genomic hybridization to 32 primary melanomas to discover and map genomic regions with aberrant DNA copy numbers. The analysis was performed on native, nonamplified DNA extracted from manually dissected tumor sections. Loss of chromosome 9 was detected in 81% of the tumors, most commonly affecting the p arm. Additional common losses occurred on chromosomes 10 (63%), 6q (28%), and 8p (22%). Gains in copy number involved chromosomes 7 (50%), 8 (34%), 6p (28%), 1q (25%), 20 (13%), 17 (13%), and 2 (13%). Amplifications indicating areas harboring potential oncogenes were seen at 4q12, 5p14.3-pter, 7q33-qter, 8q12-13, 11q13.3-14.2, and 17q25. Correlations among the regions with copy number changes indicate that losses of chromosomes 9 and 10 occur early on in melanoma progression, whereas gains of chromosome 7 occur later. This sequence of events was further substantiated by an intratumoral comparison of copy number changes in areas with radial and vertical growth phase patterns. The overall pattern of regions affected by copy number changes is consistent with cytogenetic data from metastatic melanoma; however, the frequencies of involvement differ, providing further insight into the course of genetic events.

Adult rhabdomyoma of the lip

A 75-year-old man presented with a slowly enlarging crust on the left lower lip. Beneath the crust, there was a palpable nodule approximately 1 cm. A superficial punch biopsy demonstrated an actinic keratosis of the lip. A vermillonectomy with a wedge-shaped excision of the nodule was performed because invasive squamous cell carcinoma was suspected. Histologically, the tumor proved to be an adult rhabdomyoma with an overlying actinic keratosis. The tumor cells were positive for desmin and muscle-specific actin and negative for vimentin, alpha-smooth muscle actin (alpha-SMA), and S100 protein. Some areas of cross-striation were present. Only very rarely are dermatologists confronted with these slow-growing tumors with skeletal-muscle differentiation, occurring predominantly in the head and neck area of older adults. The histologic differential diagnosis includes granular cell tumor, hibernoma, oncocytoma and paraganglioma.

A lymphohistiocytic variant of anaplastic large cell lymphoma with demonstration of the t(2;5)(p23;q35) chromosome translocation

Cytogenetic investigations were performed in a case of a nodal malignant non-Hodgkin's lymphoma. Histopathological analysis from an involved lymph node as well as from a skin biopsy revealed a lymphohistiocytic variant of CD30-positive anaplastic large cell lymphoma (ALCL). A t(2;5)(p23;q35) chromosome translocation could be observed in all metaphases analysed. This finding was confirmed both by RT-PCR analysis of the NPM/ALK fusion protein and by positive staining with the p80(NPM/ALK) antibody. To the best of our knowledge, this is the first report of a t(2;5) documented by classic cytogenetics in the lymphohistiocytic variant of ALCL.

Elevated serum levels of soluble CD30 are associated with atopic dermatitis, but not with respiratory atopic disorders and allergic contact dermatitis

Type 2 helper T-cell immune responses can be demonstrated in the human atopic disorders atopic dermatitis and allergic asthma/rhinoconjunctivitis. The CD30 (Ki-1) antigen, originally described on Hodgkin and Reed-Sternberg cells, has recently been proposed as a marker of T cells with potent B-cell helper activity producing IL-5 and gamma-IFN, as well as on CD4+ and CD8+ T cells with a Th2 cytokine profile. As a soluble form of CD30 (sCD30) is released by CD30+ cells in vivo, we studied its clinical significance in atopic disorders compared with allergic contact dermatitis and healthy controls. Elevated sCD 30 levels were associated with atopic dermatitis (P < 0.0001), but not with respiratory atopic disorders or allergic contact dermatitis. sCD30 levels in patients with atopic-dermatitis were independent of serum IgE. The particular occurrence of serum sCD30 in patients with atopic dermatitis indicates a special regulatory function of CD30+ cells in this disease.

Annexins in cancer and autoimmune diseases

Several annexins have been implicated in the pathogenesis of benign and malignant neoplasms of different origins. In some tumours a suppressive action of annexins has been shown, whereas studies of other tumours indicate an involvement of annexins in tumour progression. In the light of the expression of annexins at distinct episodes of fetal development these observations point towards a functional role of annexins in cellular development and differentiation. This view is supported by data that link certain annexins to distinct pathways of signal transduction. Auto-antibodies against several annexins have been detected in patients with autoimmune diseases such as systemic lupus erythematosus, rheumatoid arthritis and inflammatory bowel disease. Until now it is unclear whether their presence reflects a relevant pathogenetic mechanism or merely represents an unspecific expression of a raised autoimmunity in these patients.

Primary neuroendocrine carcinoma of the skin with an unusual follicular lymphocytic infiltrate of the dermis

Primary neuroendocrine carcinoma of the skin (PNECS) is a rare cutaneous tumor occurring predominantly on sun-exposed skin of elderly people. This histomorphological appearance of this aggressive tumor can be highly variable depending on the predominating growth pattern. We present an unusual case of PNECS: the tumor masked by a dense lymphoid infiltrate with a well-formed follicular growth pattern. In these cases of PNECS, the differential diagnosis must be extended to lymphoid neoplasms as well as lymphoepithelial neoplasms.

Melanoma in childhood: an EORTC-MCG multicenter study on the clinico-pathological aspects

Melanoma in children is rare. Nevertheless, it is imperative that clinicians be aware that melanoma does occur in childhood. Yet there is very little information available on the clinico-pathologic variations, and the prognostic parameters of melanoma in children. This report presents the results of a multicenter study of 102 lesions originally diagnosed as cutaneous melanoma, conducted among 5 Western European countries and collected during the period 1961-1994. Criteria for inclusion in the study included: (1) diagnosis of cutaneous melanoma; (2) age up to 16 years at diagnosis; and (3) availability of representative microscopic slides. On the basis of the histologic review only, 60 lesions were confirmed as melanoma, and 42 lesions initially diagnosed as melanoma were reclassified as nevi; 31 of the latter contained a predominance of spindle cells. The only significant parameter associated with the development of metatases or fatal outcome was thickness of more than 2.00 mm. The 5-year survival rate observed in this study was 84%. Based on these findings we conclude that considerable over-diagnosis of melanomas in children occurs. In order, therefore, to give consistent epidemiological data on melanomas in children and to improve proper recognition of their diagnostic features, both by clinicians and by pathologists, we propose to set up a central registry of melanomas in children in Europe, under the auspices of the European Organization for Research and Treatment of Cancer.

Effect of wetting the mouth on aortic blood pressure just before taking sublingual nitrates

The absorption of sublingual nitrate tablets is sometimes variable. We performed a randomized controlled trial to determine whether wetting the mouth improved the decrease in aortic systolic blood pressure (BP) from sublingual nitrate tablet or spray. The 100 patients undergoing routine diagnostic cardiac catheterization were allocated to control (no nitrate), 0.3 mg sublingual nitrate tablet, 0.4 mg sublingual nitrate spray, water + 0.3 mg sublingual nitrate tablet, or water + 0.4 mg sublingual nitrate spray. Aortic systolic and diastolic BP were recorded using a fluid-filled catheter and measured off-line blind to the treatment group. Compared with control subjects, there were significant decreases in aortic systolic BP with both nitrate preparations (tablet = -7.1 mm Hg, 95% confidence interval [CI] = -12.5 to -1.6 mm Hg; spray = -8.0 mm Hg, 95% CI = -13.4 to -2.5 mm Hg). On average, water significantly increased the fall in aortic systolic BP with nitrate tablets (-5.5 mm Hg, 95% CI = -10.9 to -0.1 mm Hg, p = 0.044) but did not significantly enhance the effect of nitrate spray (-2.8 mm Hg, 95% CI = -8.3 to 2.6 mm Hg). Water significantly increased the fall in aortic diastolic BP with tablets only (-2.9 mm Hg, 95% CI = -5.5 to -0.2), and had no significant effect on heart rate. Water had a consistently larger influence on the hemodynamic effects of nitrate tablets than on the effects of nitrate spray. Patients with a dry mouth will have an increased effect from sublingual nitrate tablets if they wet their mouth before using sublingual nitrate tablets. Water does not appear to assist in the action of sublingual spray.

Interleukin-10 production in malignant melanoma: preferential detection of IL-10-secreting tumor cells in metastatic lesions

IL-10 mRNA expression and protein production in established melanoma cell lines and freshly cultured primary and metastatic melanoma cells was examined. The in situ distribution of IL-10 in native melanoma tissue was also investigated by immunohistochemistry in primary tumors, metastases, benign melanocytic nevi and normal skin of healthy persons and melanoma patients. IL-10 mRNA, but not IL-10 protein in the culture supernatant, was found in 1 of 4 cultured melanoma cells of primary tumors, while 3 of 6 melanoma-metastasis-derived cultures expressed both IL-10 mRNA and protein. No IL-10 was detected in skin biopsies of healthy volunteers or in the healthy skin of melanoma patients; nor was IL-10 found in congenital melanocytic nevi. In only 1 of the 11 examined primary malignant melanomas was IL-10 immunoreactivity detected within the cytoplasm of cells in the tumor. On the other hand, 4 of 9 metastases clearly displayed scattered IL-1O+ cells. In all sections with IL-10-positive cells, the cells were positive for HMB-45. No co-expression of CD3 and IL-10 was observed. The data suggest that melanoma cells themselves are the main origin of IL-10 in tumor specimens in vivo. The preferential expression of IL-10 in metastatic lesions and in cultured cells from metastases might indicate an increased spreading potential of IL-10-secreting melanoma-cell clones.

[Giant cell fibroblastoma. A rare soft tissue tumor in childhood]

We report on a 9-year-old girl with a giant cell fibroblastoma of the right anterior chest wall. This rare soft tissue tumour occurs predominantly in the first two decades of life. The typical clinical presentation is a solitary, usually 2-6 cm large, non-tender mass of blue-greyish colour which is mostly located on the back, anterior chest wall, thigh or groin. The histology shows a loose infiltrate of predominantly bland spindle cells in dermis and subcutis. Characteristic elements of the tumour are large angiectoid branching spaces lacking any endo- or epithelium, and relatively small multinucleated cells (floret cells). The recurrence rate is high if the tumour is not excised with adequate safety margins. Metastases are not reported. It is of pre-eminent importance to differentiate this rare benign tumor from sarcomas, in order to avoid an inappropriately aggressive therapy.

[Microcystic adnexal carcinoma of the skin. An underestimated tumor]

Microcystic adnexal carcinoma is a rare semimalignant cutaneous neoplasm characterised by slow but locally aggressive growth. Its histogenesis and nomenclature are still a subject of controversy. Under-recognition and the tumor's bland cytologic features lead to frequent misdiagnoses. In addition, subclinical tumour invasion explains the high incidence of local recurrence. Thus, the tumour makes great demands on the planning of its surgical removal. We report the case of an 81-year-old woman with a microcystic adnexal carcinoma of the lower lip, which was treated by micrographic surgery. On the basis of this case, differential diagnoses, histogenesis and micrographic surgery as the treatment of choice are discussed.

Phospholipase A2 is secreted by murine keratinocytes after stimulation with IL-1 alpha and TNF-alpha

Phospholipase A2 (PLA2)-catalysed liberation of arachidonic acid is the rate-limiting step in the generation of the lipid mediators prostaglandins and leukotrienes. PLA2 regulation thus represents a pivotal mechanism in the pathogenesis of inflammation. In this study we investigated the effects of TNF alpha and IL-1 alpha on PLA2 activity in cultured murine keratinocytes. Starting 18 h after stimulation, PLA2 activity increased significantly by about 250-320%) in the supernatants and in the cell pellets. This effect was completely inhibited either by preincubation of the cells with dexamethasone 48 h before stimulation or by coincubation with actinomycin D. PLA2 activity detected in the supernatants was blocked by reduction with dithiothreitol, whereas the PLA2 activity in the pellets was dithiothreitol-resistant. We conclude that in murine keratinocytes IL-1 alpha induce de novo synthesis and release of a secretory PLA2 and the induction of a different PLA2 activity in the cytosol. These findings indicate a crucial link between early cytokine effects and the initiation of the lipid mediator cascade in keratinocytes. The observation that PLA2 induction could be completely inhibited by preincubation with dexamethasone allows new insights into the mechanism of steroid effects on epidermal inflammation and renders PLA2 regulation an interesting therapeutic target.

Preoperative characterization of pigmented skin lesions by epiluminescence microscopy and high-frequency ultrasound

BACKGROUND AND DESIGN

Previous studies have referred to the value of epiluminescence microscopy in the differential diagnosis of pigmented skin lesions and to the possibility of preoperative tumor thickness measurement in malignant melanoma by high-frequency ultrasound. Both noninvasive methods have been combined in this study. The question of improved diagnostic accuracy was discussed. Previously proposed epiluminescence microscopic characteristics of 508 melanocytic lesions and sonographic characteristics of 792 skin tumors were investigated for their sensitivity and specificity. The tumor thickness of 108 malignant melanomas was measured sonographically.

RESULTS

Black dots, irregular pigment network, and grayish-blue areas have been shown to be the most sensitive characteristics, whereas pseudopods, grayish-blue areas, and a whitish veil have been shown to be the most specific epiluminescence microscopic features for malignant melanoma. Sonography alone cannot reliably distinguish between different skin tumors. Preoperatively, the tumor thickness of 85% of the melanomas was assessed correctly concerning the pT stage.

CONCLUSIONS

A 20-MHz ultrasound, in addition to epiluminescence microscopy, may improve the diagnostic accuracy by delivering information about depth and topographic location of skin tumors, but cannot give highly specific information about tissue dignity. It is a reliable tool for tumor thickness measurement for surgical planning.

Autoantibodies to annexins: a diagnostic marker for cutaneous disorders?

Annexins/lipocortins are a group of structurally related calcium and lipid binding proteins which have been implicated as mediators of the anti-inflammatory action of corticosteroids. Autoantibodies against annexin-1 have been reported in association with autoimmune diseases such as systemic lupus erythematosus and rheumatoid arthritis and their presence has been hypothesized as the reason for the steroid resistance phenomenon. In this study we investigated IgG- and IgM-autoantibodies against annexin-1,-2,-3,-4,-5 and -6 in sera of 221 patients with skin disorders and 114 healthy blood donors with newly established ELISAs. Patients were clustered into 5 groups according to their diagnosis: autoimmune diseases, psoriasis, leg ulcer, malignant melanoma, and miscellaneous diseases. Autoantibodies directed against each annexin were detectable in all investigated groups, in the control group as well as in the disease groups, without displaying any significant correlation to any of the disease states. The homogenous distribution of annexin-autoantibodies throughout the control group and all the disease groups studied, do not support the implication of annexin-autoantibodies in pathophysiological states and make them an unlikely candidate for use as a diagnostic marker.

[Benign giant cell tumor of the tendon sheath. A differential diagnosis of cutaneous tumors near the joint]

Giant cell tumour of the tendon sheath, though rather a common connective tissue tumour, is rarely mentioned in the dermatological literature. It is a benign, slow-growing tumour arising from the synovia and it is most frequently located on the joints of the fingers. It becomes manifest clinically as a firm, skin-coloured nodule fixed to the underlying tissue. The histological picture is characteristic and shows osteoclast-like giant cells, histiocytic cells, foam cells and focal haemosiderosis. It probably reflects a reactive process similar to that of fibrous histiocytoma. The therapy of choice is excision, with a small margin of uninvolved tissue to avoid recurrences.

Localization of annexins in normal and diseased human skin

Annexins (AX) or lipocortins are a family of calcium and phospholipid binding proteins that have been implicated to play a role in the regulation of inflammation and cellular differentiation. To investigate a potential role of AX in skin disorders we studied the distribution of six different AX in normal human skin (NHS) and several inflammatory and hyperproliferative skin diseases. A distinct staining pattern could only be shown for AX-1 and AX-2. In NHS AX-1-antibody (Ab) displayed a very strong reactivity with eccrine sweat ducts. In the diseases investigated we found a highly increased expression of AX-1 in keratinocytes (KCs) in the vicinity of inflammatory processes such as psoriasis. Furthermore, the AX-1 expression was increased in differentiated squamous cell carcinoma (SCC) whereas undifferentiated SCC and basal cell carcinoma were negative. AX-3, -4, -5, and -6 showed no distinctive expression pattern. Our data demonstrate an abnormal distribution of AX-1 in association with proliferating KCs under inflammatory and neoplastic conditions. Its pattern of reactivity shows similarities to the known distribution of the EGF-receptor kinase, which has been demonstrated to phosphorylate AX-1 with high activity in various cellular systems. These results support the concept that the appearance of AX-1 is linked to a certain level of KC differentiation.

Inhibition of human skin phospholipase A2 by "lipocortins" is an indirect effect of substrate/lipocortin interaction

Proteins of the annexin/lipocortin family have been claimed to mediate the anti-inflammatory action of glucocorticosteroids by the inhibition of phospholipases A2. This hypothesis has been challenged by the finding that annexins do not directly interact with the enzyme in a classical enzyme/inhibitor behavior, but more likely block the access of the phospholipase A2 to its substrate by binding to phospholipids. Because former studies with skin phospholipase A2 suggested a specific regulation by annexin-1, we investigated the substrate dependence of this effect. For this purpose phospholipase A2 activities in human epidermis and dermis homogenates were measured in the presence of various amounts of annexins-1, -2, or -5. The respective annexin was preincubated in separate series either with the substrate or with the enzyme. We found a partial inhibition of both epidermal and dermal phospholipase A2 activities with all annexins tested (annexin-5 >> annexin-2 > annexin-1). The inhibitory effect was absolutely dependent on the annexin/phospholipid ratio and occurred only at very high annexin concentrations relative to the amount of substrate. Our data demonstrate that the inhibition of human skin phospholipase A2 by annexins depends on the substrate concentrations, as has been shown for phospholipases A2 of other origins as well. All observations can be explained by the current "substrate depletion model" characterizing the indirect effects of annexins on phospholipase A2 activities. It is therefore rather unlikely that annexins are directly involved in the regulation of phospholipase A2 activity of human skin under physiologic conditions.

[Lipocortins and phospholipases: new aspects in the physiology of glucocorticosteroid effect]

Glucocorticosteroids are among the most useful and most widely prescribed anti-inflammatory drugs. Despite their wide use little is yet known about their mode of action. In the last 10 years a group of proteins called lipocortins or annexins has been characterized. Those proteins exert an inhibitory effect on the synthesis of lipid mediators by way of an important proinflammatory enzyme, phospholipase A2. Phospholipases are known to be involved in cell-signal transduction and generation of inflammatory mediators like prostaglandins, leukotrienes and platelet-activating-factor. The cellular expression of lipocortins is induced by glucocorticosteroids. The inhibition of cellular phospholipases via lipocortins may account for some aspects of the action of glucocorticosteroids.

[Computer networks in clinical practice--a histology data bank system]

In hospital and in private practice huge amounts of data have to be managed. Conventional storage and documentation techniques are being replaced more and more by the use of computers. Local area networks based on the interconnection of stand-alone PC workstations offer several advantages over non-communicating systems. The use of computer networks solves many communication problems and in this way improves the flow of information. The interconnection may be achieved by step-by-step integration of preexisting elements. This paper presents a database system for archiving routine histology data and illustrates the use of a computer network in a dermatology department.

Giant lichenification of the vulva with marked ulcerations. A case report

A case of vulvar giant lichenification of Pautrier showed uncommon ulcerations in the center of hyperplastic verrucoid plaques. The diagnosis was made from the history, clinical findings and characteristic features on the skin biopsy. Other causes of vulvar ulcers, such as venereal disease, chronic bullous and autoimmune diseases, and neoplastic conditions were excluded. We treated the patient with systemic antihistamines, topical antiseptics and corticosteroids, and sublesional injections of triamcinolone. The itch-scratch cycle was interrupted by the patient's wearing cotton gloves at night. Complete healing of the ulcers and an improvement in the pruritus was achieved within 14 weeks.

Abnormal cardiovascular regulation in the mitral valve prolapse syndrome

Studies of patients with mitral valve prolapse syndrome have suggested autonomic nervous system dysfunction, but a precise definition of mechanisms is lacking. We measured supine and standing heart rate, blood pressure, cardiac output, oxygen consumption, plasma catecholamines, and blood volume in 23 symptomatic women with both echocardiographic and phonographic signs of MVP and in 17 normal control subjects. An analysis of the results revealed 2 distinct subgroups of patients: those with normal heart rates but increased vasoconstriction (Group I, n = 10) and those with orthostatic tachycardia (Group II, n = 13). Group II patients had heart rates at rest supine of 97 +/- 3 compared with 79 +/- 2 in Group I patients and 78 +/- 8 in control subjects. Estimated total blood volumes were lowest in Group I patients, intermediate in Group II patients, and highest in control subjects (p less than 0.05). Other measurements at rest supine were similar in patients and controls. After standing for 5 minutes, patients had a higher mean plasma epinephrine value, diastolic blood pressure (81 +/- 2 versus 74 +/- 3 mm Hg, p less than 0.05), and peripheral resistance (1,878 +/- 114 versus 1,414 +/- 92, dynes s cm-5, p less than 0.01), wider arteriovenous oxygen difference (6.7 +/- 0.4 versus 5.3 +/- 0.5 vol%), and lower stroke volume index (26 +/- 2 versus 33 +/- 2 ml/m2, p less than 0.01) than did the control subjects. Cardiac output was normal in Group II patients but reduced in Group I patients, who demonstrated marked vasoconstriction. No patient had evidence of a "hyperkinetic" circulatory state. A cycle of decreased forward stroke volume, vasoconstriction, and blood volume contraction appears to be present in at least some symptomatic patients with MVP.

Haemodynamic responses to static and dynamic handgrip before and after autonomic blockade

1. Six healthy men performed static and dynamic handgrip to local muscular fatigue in approximately 6 min under control conditions, i.e. without drugs and after combined parasympathetic and beta-adrenergic blockade with atropine and metoprolol. 2. From rest to exercise at fatigue, systolic, diastolic and mean arterial pressures increased by 32 +/- 4 and 39 +/- 3 mmHg, 24 +/- 3 and 26 +/- 4 mmHg, and 26 +/- 3 and 30 +/- 3 mmHg respectively for static and dynamic handgrip. There were no significant differences between the pressor responses for the two modes of contraction. Cardiac output increased significantly only during dynamic exercise. Total peripheral resistance increased by 2.3 +/- 1.0 units for static handgrip (P less than 0.05) and by 0.7 +/- 0.8 unit (P greater than 0.05) for dynamic handgrip. Autonomic blockade abolished the heart rate response to both static and dynamic handgrip. For both modes of contraction the systolic arterial pressure responses were 9-12 mmHg lower (P less than 0.05) after autonomic blockade, but the diastolic and mean pressure responses were not significantly affected. A significant increase in cardiac output persisted during dynamic exercise. The increase in peripheral resistance during static exercise tended to be greater after blockade. Plasma noradrenaline and adrenaline levels showed only minor elevations in response to static and dynamic handgrip and were not changed by autonomic blockade. 3. These data indicate that when performed to a common end-point with identical small muscle groups static and dynamic exercise produce an equally large pressor response, which is only slightly attenuated by autonomic blockade.

Passive leg raising does not produce a significant or sustained autotransfusion effect

Passive leg raising is widely used to treat hypotension associated with hypovolemia. Presumably gravity causes a central translocation of leg venous blood and an increase in filling pressure, cardiac output, and arterial pressure. Ten healthy volunteers, 25 to 35 years old, had measurements of heart rate, blood pressure, and cardiac output in the supine position after 20 sec and 7 min of 60 degrees passive leg elevation. The protocol was performed 3 and 45 min after the subjects changed from an ambulatory upright to a supine position. Stroke volume and cardiac output increased transiently (8-10%) when the legs were raised after 3 min rest in the supine position. By 7 min of leg elevation, these beneficial effects disappeared. After 45 min supine, leg raising had no effect on stroke volume or cardiac output but increased blood pressure (4 mm Hg) by increasing peripheral resistance (15%). Thus, leg raising, like application of the MAST trousers, fails to produce any sustained increase in cardiac output or stroke volume. Small venous leg volumes and time-dependent changes in the distribution of venous volume and compliance may explain the absence of any sustained 'autotransfusion' effect.

Hemodynamic effects of Medical Anti-Shock Trousers (MAST garment)

Despite widespread use of the Medical Anti-Shock Trousers (MAST) little is known about the exact mechanism by which they increase arterial pressure. It is assumed that an autotransfusion occurs. To examine this question, blood pressure, heart rate, forearm blood flow, cardiac output, and stroke volume were measured in ten healthy adults, supine and during 60 degree headup tilt with MAST garment pressures of 409 and 100 mm Hg. Supine, the garment produced no net 'autotransfusion,' but raised blood pressure (27%) by increasing peripheral resistance (48%) with decreased stroke volume and cardiac output (18%). During headup tilt without the MAST device, venous pooling in the legs decreased stroke volume (52%), cardiac output (30%), and increased total peripheral resistance (40%). Application of the garment during tilt shifted this blood centrally, producing increased stroke volume (52%), cardiac output (30%), and increased total peripheral resistance (40%). Application of the garment during tilt shifted this blood centrally, producing increased stroke volume (14%). In supine normovolemic subjects, the garment raised pressure almost exclusively by increased systemic afterload. Forearm vascular resistance did not change and the increased pressure augmented flow to the arm, i.e., to noncompressed tissue. With increased venous pooling during tilt, the MAST garment acted as a 'G-suit' and caused a central shift of blood volume. These findings could explain: 1) why fluid replacement is not always adequate to maintain pressure when deflating the trousers; 2) why the trousers should not be used if one wishes to avoid increasing afterload (e.g., certain patients with acute myocardial infarction). We conclude that the MAST garment acts as a local, effective, nonpharmacologic vasoconstrictor and should be used when such an effect is clinically appropriate.

Total plasma creatinine: an accurate measure of total striated muscle mass

Creatinine is a metabolite unique to striated muscle. Measurement of 24-h urinary creatinine excretion is an established method for estimating striated muscle mass. However, accurate assessment of urinary creatinine excretion is often impractical. We investigated the hypothesis that total plasma creatinine could be used instead of urinary creatinine excretion to estimate body composition. In 24 men, plasma volume and plasma creatinine concentration were measured, and total plasma creatinine was calculated as the product of these two measurements. Other measurements included urinary creatinine excretion, total body water, and anthropometry. Total plasma creatinine correlated strongly with urinary creatinine excretion (r = 0.82) and with weight, total body water, and anthropometrically estimated lean body mass. Muscle mass could be predicted by the equation: 0.88 x total plasma creatinine (mg). To verify this relationship, total plasma creatinine was prospectively measured in four dogs, then their total striated muscle was removed and weighed. Predicted muscle mass was within +/- 3.9% (range = 0.5-10.8%) of observed muscle mass. The ability to estimate muscle mass conveniently and accurately from total plasma creatinine should prove valuable for future studies in physiology and body composition.

A prospective randomized trial of tocainide in patients following myocardial infarction

One hundred forty-six patients with recent acute myocardial infarction were grouped at random into those treated with tocainide, an oral analogue of lignocaine, or placebo and followed up for 6 months. In addition to standard investigations, a 24-hour ambulatory taped ECG recording was obtained prior to randomization and thereafter at 2, 8, 16, and 24 hours after discharge. The ECGs were analyzed by means of an automated, computerized reporting system. Forty-two patients had significant ventricular arrhythmias, 10 of whom had effective plasma levels of tocainide compared with 27 patients on placebo (P < 0.005). In the placebo patients with increasing mobilization there was a consistent rise in the number of ventricular ectopic beats per day. There was no such increase in the tocainide patients (P < 0.01). Side effects were few and the incidence of central nervous system side effects was similar in both the tocainide and placebo groups. There was no conclusive evidence of myocardial depression, heart rate and blood pressure being unchanged over the 6-month period. Although ventricular arrhythmias were suppressed, the number of patients in the study was too small to draw conclusions regarding the mortality rate.