N S Penneys’s research while affiliated with Washington University in St. Louis and other places

CD44 is a widely distributed cell surface protein thought to be involved in multiple steps of normal immune cell function, including T-cell activation, and in cellular adhesion where it mediates cell attachment to hyaluronate. In normal skin, CD44 is found by immunohistochemical means to be primarily in eccrine coil cells. In this study, we have looked at the expression of CD44 in normal scalp and in two different hair disorders, androgenetic alopecia and alopecia areata. In normal scalp and androgenetic alopecia, CD44 was found in its normal distribution in eccrine coil cells. In scalp of 30 patients with alopecia areata, there was no expression of this glycoprotein. Patients were also assessed pre and post treatment for their alopecia areata, and even though they had no significant hair regrowth, 2 patients regained expression of CD44, indicating a variable expression of this protein in the alopecia areata disease process. The absence of CD44 expression in alopecia areata-affected scalp may give further information regarding the pathogenesis of this disease.

Reductions in reimbursement are applied to all physicians in a region equally. However, physicians do not practice in equivalent situations. For example, there are few fiscal allowances for academic functions associated with teaching and administration. Furthermore, university-based physicians may practice in clinical venues that cannot be as efficient as nonuniversity sites. Unavoidable inefficiencies may include (1) the costs of maintaining one historical record for a large noncontiguous practice; (2) university-required holiday schedules and sick leave, making university personnel less productive; (3) noncompetitive overhead rates assigned to clinic components by university financial offices; (4) university-based accounting systems that are not designed for effective cost control and the timely generation of useful management information; and (5) poorly managed billing services. Until now, declining reimbursements have generally led to sufficient efficiencies in delivery so that revenues and expenses can be in equilibrium.

Focal adhesion kinase is a protein-tyrosine kinase that is found in cellular contact sites and is phosphorylated in response to cell attachment. It is possible that the immunohistochemical detection of this enzyme might be increased in keratinocytes involved in an acantholytic process. Normal skin, pemphigus vulgaris and foliaceus, Darier's disease, Hailey--Hailey disease, warty dyskeratoma, Grover's disease and spongiotic dermatitis were assayed for the immunohistochemical expression of focal adhesion kinase. Focal adhesion kinase was not observed in normal epidermis. This antigen was observed in keratinocytes adjacent to acantholytic spaces and in acantholytic cells in pemphigus vulgaris and foliaceus. Focal adhesion kinase was not detected in keratinocytes involved in focal acantholytic dyskeratoses such as Darier's disease, Grover's disease and warty dyskeratoma but was weakly detected in Hailey--Hailey disease. One consequence of immunologically mediated acantholysis is the upregulation of focal adhesion kinase possibly as a component of biochemical pathways that reconstruct the process of adhesion or respond to the process of acantholysis.

The polymerase chain reaction (PCR) is a molecular diagnostic technique that has been applied to many infectious processes. Stained and unstained Tzanck smears, vesicle fluid swabs, and crusts have all been used as the source for template DNA for the PCR to document evidence of herpes simplex virus and varicella-zoster virus infection. Thirty-five cases with histologic evidence of acute herpesvirus infection were retrieved from archival tissue blocks that were up to 5 years old. Paraffin and hematoxylin-eosin-stained tissue sections obtained from routinely prepared glass slides from these cases were then examined for herpesvirus DNA using the PCR. The PCR-detected herpesvirus DNA from 34 (97.1%) of 35 paraffin tissue samples. Herpes simplex virus and varicella-zoster virus DNA were detected in eight and 26 of these cases, respectively. For hematoxylin-eosin-stained tissue samples, PCR detected herpesvirus DNA sequences in 16 (45.7%) of 35 cases. Herpesvirus DNA was isolated from paraffin tissue sections and recently prepared hematoxylin-eosin-stained tissue samples obtained from archival tissue blocks that were up to 5 and 2 years old, respectively. The PCR can detect herpesvirus DNA in extremely high yield from unstained paraffin-embedded tissue samples with histologic evidence of acute herpesvirus infection that are up to 5 years old. Herpesvirus DNA can also be identified in approximately 50% of these cases from hematoxylin-eosin-stained tissue sections obtained from routinely prepared glass slides.

Epithelioid and spindle cell nevus (ESN; Spitz nevus) is a histologically well-described entity. We hypothesized that the features of ESN may reflect activation by a proliferative stimulus. Nevocytes and keratinocytes in ESN and control specimens were examined for expression of the proliferation marker, proliferating cell nuclear antigen (PCNA). Standard immunohistochemical methods were used to examine the expression of PCNA in a series of ESN, other nevi, and malignant melanoma. PCNA was detected in nevocytes in a significant percentage of ESN but not in other nevi. PCNA expression was increased in basilar keratinocytes in ESN when compared with staining of basilar keratinocytes in normal epidermis. In other melanocytic nevi and noninflamed melanoma, PCNA expression in keratinocytes was similar to that in normal control tissue. Increased PCNA labeling in nevocytes and keratinocytes in ESN suggests that a growth stimulus, present within some of these lesions, affects both keratinocytes and nevocytes.

Merkel cells are an integral component of the cutaneous nervous system. They are commonly associated with dermal nerves under normal physiological conditions. We postulated that Merkel cells may be present in increased numbers within the epidermis overlying benign peripheral nerve sheath tumours such as neurilemomas and neurofibromas. Paraffin-embedded skin biopsy specimens from 21 patients with neurilemomas and 26 with neurofibromas, were analysed for the presence of Merkel cells using a standard immunohistochemical assay (avidin-biotin-peroxidase complex system) with an antibody to cytokeratin 8 (CAM 5.2). Ten cases of leiomyomas were examined as controls. Merkel cells were identified in the interfollicular area of the basal cell layer overlying 14 of 21 (67%) neurilemomas and nine of 26 (35%) neurofibromas. Merkel cells were more frequently observed in increased numbers in a linear array within the basal cell layer in neurilemomas than in neurofibromas, where they were found as individual cells. No Merkel cells were found in the epidermis overlying leiomyomas. The results of this study suggest that Merkel cells are quantitatively increased in the basal cell layer of the epidermis overlying benign peripheral nerve sheath tumours, particularly neurilemomas.

CD44 is a widely distributed cell surface protein thought to be involved in multiple steps of normal immune cell function, including T-cell activation, and in cellular adhesion where it mediates cell attachment to hyaluronate. In normal skin, CD44 is found by immunohistochemical means to be primarily in eccrine coil cells. In this study, we have looked at the expression of CD44 in normal scalp and in two different hair disorders, androgenetic alopecia and alopecia areata. In normal scalp and androgenetic alopecia, CD44 was found in its normal distribution in eccrine coil cells. In scalp of 30 patients with alopecia areata, there was no expression of this glycoprotein. Patients were also assessed pre and post treatment for their alopecia areata, and even though they had no significant hair regrowth, 2 patients regained expression of CD44, indicating a variable expression of this protein in the alopecia areata disease process. The absence of CD44 expression in alopecia areata-affected scalp may give further information regarding the pathogenesis of this disease.

A spectrum of skin lesions are believed to be secondary to the presence of Mycobacterium tuberculosis. Demonstration of M tuberculosis directly or in culture in some of these eruptions can be difficult. We used the polymerase chain reaction and a primer/probe set specifically for M tuberculosis complex DNA to evaluate five types of skin lesions clinically considered to represent infection by, or reaction to, M tuberculosis. Mycobacterium tuberculosis DNA was demonstrated in paraffin-embedded sections of these five cases, representing a variety of clinical and histologic patterns. In two cases, M tuberculosis could not be demonstrated by routine cultural methods. DNA diagnostic methods such as the polymerase chain reaction can be used to rapidly identify cutaneous lesions produced by M tuberculosis.