bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of molar rotation on arch length
Authors: McDonald John L. , Shofer Frances S. , Ghafari Joseph
Published: March 2003

The aim of this study was to evaluate the effect of maxillary first molar rotation on arch length in patients whose Class II, division 1 malocclusion was treated with a straight‐pull headgear. The sample included 19 children who represent a subset of a population enrolled for 2 years in a prospective clinical trial of Class II treatment. The inner bow was adjusted at monthly visits and the average distalizing force was 14–16 oz per side. Measurements were made with digital calipers on casts obtained at baseline and at a time point averaging 16 months (SD 3 months) into treatment. Molar movement was related to a coordinate system referenced to the midpalatal raphae and the occlusal plane through a palatal plug that could be transferred to successive casts of the same patient. Distances from the cusp tips were measured to the reference system. The distal and lateral displacement, and the rotation of the molars over time were then computed. High correlations were observed between molar rotation and tooth displacement (that is the net differential movement between the mesiobuccal – MB – and mesiopalatal – MP – cusps): r=0.9, p=0.0001 (left side); r=0.8, p=0.0001 (right side). The average rotation of the molar was 15.4° (SE±3.80) on the left side and 10.8° (SE±2.20) on the right side. The average differential displacements between the MB and MP cusps were 1.04 mm (SE±0.29) (left) and 0.73 mm (SE±0.23) (right). The differences between the two sides were not statistically significant. The molar rotation did not correlate with any of the following parameters: initial tooth position; initial distance between the MB and MP cusps as a correlate of molar anatomy; transverse (mostly buccal) movement of the MB and MP cusps; distal movement of the tooth, as measured by the total displacement of the MB and MP cusps. This study qualifies the relationship between molar rotation and increase in arch length. The mean total distal movement of the molar was larger (nearly 3 mm) than the average contribution of molar rotation to space gain (about 1 mm), suggesting that the distal movement of the tooth was a combination of rotation and translation (or tipping). The contribution of the molar rotation is more significant with a smaller total displacement of the tooth.
Reappraisal of Class II molar relationships diagnosed from the lingual side
Authors: D Liu , B Melsen
Published: March 2003

The buccal and lingual molar relationships in 459 clinically diagnosed Class II cases and the impact of upper first permanent molar rotation on this classification were assessed. Of the 459 Class II cases, 99 (10.78%) sides exhibited unilateral neutral molar relationship assessed from both the buccal and the lingual aspect. None of the molars exhibiting Class I relationship were rotated. The 175 (19.06%) sides with mild Class II molar relationship from the buccal aspect were all judged to be Class I lingually and 85% of these molars were rotated mesially. In the case of a moderate buccal Class II tendency, 55% of the molars were in a Class I relationship when evaluated from the lingual side, whereas 45% belonged to mild (1st°) Class II with molar rotations present in 81% of the cases. When a severe (3rd°) Class II was present from the buccal side, its corresponding lingual Class II tendencies were accordingly elevated (83% 2nd°, 17% 3rd°). Among these cases, the molar rotations occurred in 74% of the cases. The results suggested the upper mesiopalatal cusp as a pivotal axis around which the upper first molar rotated. This cusp occluded most frequently in the central fossa, less frequently in the mesio‐triangular fossa and rarely anterior to the mesio‐triangular fossa. Rotations that correspond to these types of lingual occlusion were 85, 81 and 74%, respectively. The correlation between buccal and lingual molar relationships and their correlation with molar rotation were all significant (p<0.001). Moreover, canine relationship was linearly correlated with the conventional (buccal) molar relationship in Class II cases, expressed by Ycanine relation=1.423+0.47 Xmolar relation (p<0.001). The results indicate that a more differentiated diagnosis of the molar relationship will allow for a more causally directed correction of Class II molar relationship.
Breadth of the mandibular condyle affected by disturbances of the sex hormones in ovariectomized and orchiectomized mice
Authors: Fujita Tadashi , Kawata Toshitsugu , Tokimasa Chiyoko , Kohno Shinya , Kaku Masato , Tanne Kazuo
Published: March 2003

It is well known that the size of the condyle is different between males and females in humans. It has also been documented that ovariectomy (OVX) and orchiectomy (ORX) influence the remodeling of the condylar head in experimental animals. However, influences of sex hormones on the condyle in terms of its breadth have not been examined. With these considerations, this study was designed to examine the breadth of the mandibular condyle in OVX and ORX mice by histomorphometry 8 weeks after surgery. In the OVX mice, the condylar breadth was significantly larger than in the controls, while no significant differences in the breadth were found between the ORX mice and the controls. The thickness of the condylar cartilage layers exhibited similar findings to the breadth of the condyle. On the contrary, the trabecular bone volume was significantly smaller in the OVX and ORX mice than in the corresponding controls, and the difference was more substantial in female mice than in the males. These findings emphasize that a reduction of sex hormone levels, induced by OVX and ORX, significantly influences condylar morphogenesis.
Dermatofibroma is a clonal proliferative disease
Authors: Chen Tse‐Ching , Kuo Tseng‐tong , Chan Heng‐Leong
Published: March 2003

Benign fibrous histiocytoma of the skin or dermatofibroma (DF) has been regarded as a fibrohistiocytic tumor. Whether DF is a neoplastic growth or a reactive process has not been settled. Since a neoplastic process is clonal in nature, clonal analysis of DF was conducted to see if DF is a clonal disease. Fresh specimens of 13 DFs and 2 hypertrophic scars obtained from female patients were studied. The adjacent nonlesional skin tissues served as controls. The clonal analysis was based on the methylation pattern of the polymorphic X‐chromosome linked androgen‐receptor gene (HUMARA). Eight DFs and 1 hypertrophic scar were heterozygous at the androgen receptor gene and could be analyzed. All 8 informative DFs showed a significant reduction in one of the allelic bands compared with the corresponding bands of the nonlesional tissue after Hha I digestion. Therefore, DF is a clonal proliferative disease. In contrast, 1 hypertrophic scar showed a polyclonal pattern of X‐chromosome inactivation. We conclude that DF is a clonal disease favoring a neoplastic process.
Pigmented squamous cell carcinoma
Authors: Chapman M. Shane , Quitadamo Mark J. , Perry Ann E.
Published: March 2003

Pigmented squamous cell carcinomas have been reported in the oral and ocular mucosae, but rarely in the skin. We present a case of pigmented squamous cell carcinoma of the forehead and review the current English literature. Pigmented squamous cell carcinoma can be confused with pigmented basal cell carcinomas and melanoma, especially those melanomas associated with pseudoepitheliomatous hyperplasia and should be included in the differential diagnosis of atypical pigmented lesions.
Factor XIIIa+ dermal dendrocytes in erythema elevatum diutinum and ordinary cutaneous leukocytoclastic vasculitis lesions
Authors: Pacheco Laura Scatena , Sotto Mírian N.
Published: March 2003

Factor XIIIa+ dermal dendrocytes belong to the dermal microvascular unit and are related to wound healing, angiogenic and fibrogenic processes. Erythema elevatum diutinum (EED) is a leukocytoclastic vasculitis followed by repair and fibrosis. In order to verify the involvement of fXIIIa+DD in the pathogenesis of EED and ordinary leukocytoclastic vasculitis (OLV) these cells were immune labeled with anti‐factor XIIIa antibody and quantified in 15 biopsies of EED, 18 of OLV and compared with 11 fragments of normal skin (NS). The number of vessels was evaluated by endothelial cell staining with anti CD34 antibody. FXIIIa+DD appeared in both groups of vasculitis with hyperthophic dendrites, with no difference in their number at any level of the dermis. The number of fXIIIa+DD in the superficial dermis was higher in OLV than in NS (p<0.001). The number of dermal vessels in the EED group was higher at all dermis depths evaluated when compared with NS (p<0.05) and in the middle and deep dermis when compared with OLV (p<0.05). The results suggest the participation of fXIIIa+DD in the immunopathological mechanisms of both groups of vasculitis studied. However, there was no correlation between the number of fXIIIa+DD and angiogenesis and fibrogenesis in the EED lesions.
Keratotic melanocytic nevus: a clinicopathologic and immunohistochemical study
Authors: Horenstein Marcelo G. , Prieto Victor G. , Burchette James L. , Shea Christopher R.
Published: March 2003

Background: Epidermal hyperplasia in melanocytic nevi is a common but little‐investigated phenomenon.

Methods: We prospectively examined all melanocytic nevi diagnosed in our department over an 8‐month period, for the criteria of keratotic melanocytic nevus (KMN), namely the presence of marked epidermal hyperplasia with or without horn pseudocyst formation, hyperkeratosis, and papillomatosis. In addition to routine histologic review, we studied 12 representative cases with immunohistochemistry to examine expression of Ki‐67, epidermal growth factor receptor (EGFR), Bcl‐2, and Bax.

Results: From a total of 1527 melanocytic nevi, 95 were KMN (prevalence 6%). The average age was 34 years, with a male:female ratio of 1:2. The predominant location was the trunk (76%), followed by head and neck (20%), and extremities (4%). Clinical diagnoses were atypical nevus (44%), nevus not otherwise specified (43%), and others including seborrheic keratosis, acrochordon, and basal cell carcinoma. Two KMN were junctional, 44 compound, and 49 intradermal. Twenty‐three KMN (24%) had histologic features suggesting congenital onset, and 15 (16%) had mild to moderate dysplastic features. Two cases demonstrated induction of sebaceous glands. Significantly increased Ki‐67 expression was detected in the hyperplastic epidermis, particularly in deeper areas related to keratinous cysts and hair follicles. Bcl‐2 and Bax (anti‐ and pro‐apoptosis proteins, respectively) and EGFR were expressed similarly in both normal and hyperplastic epidermis overlying the KMN.

Conclusions: KMN are commonly biopsied skin lesions, mostly located on the trunk. Many such lesions are clinically considered atypical, in contrast to their benign histologic appearance. The epidermal hyperplasia on top of KMN demonstrates increased cellular proliferation, in the context of adequately regulated apoptosis and EGFR expression. The cellular proliferation seems to commence in hair follicles.
A case of intravascular large B‐cell lymphoma mimicking erythema nodosum: the importance of multiple skin biopsies
Authors: Kiyohara T. , Kumakiri M. , Kobayashi H. , Shimizu T. , Ohkawara A. , Ohnuki M.
Published: March 2003

Background: Intravascular lymphoma is a rare disease characterized by the proliferation of neoplastic monuclear cells within the lumens of small blood vessels. The neoplastic cells are usually of B‐cell origin, and rarely of T‐cell or histiocytic origin. Although this clinicopathological entity of lymphoma has not been listed in general pathological classifications such as REAL classification or the Working Formulation, it is recently in the WHO classification scheme, which is essentially an updated REAL scheme, and the EORTC classification scheme.

Methods: In this report, a 62‐year‐old woman with intravascular large B‐cell lymphoma was observed by clinical, histopathological, immunohistochemical and molecular methods.

Results: A 62‐year‐old woman presented with large erythematous macules on the bilateral thighs and lower legs. The lesions were accompanied with hard, tender, intradermal or subcutaneous nodules mimicking erythema nodosum. Histopathological examination in the first biopsy revealed non‐specific panniculitis compatible with erythema nodosum. The second biopsy revealed emboli of atypical lymphocytes within many of the dilated and proliferated vessels in the deep dermis and subcutaneous tissue. These cells were positive for L‐26 and kappa light chain, and negative for lambda light chain, factor VIII‐related antigen, CD30, CD34, CD68 and UCHL‐1. These findings confirmed the diagnosis of intravasular large B‐cell lymphoma. A laboratory examination showed a high level of LDH and abnormal cells in the bone marrow. An MRI of the brain and computed tomographic (CT) scans of the chest and abdomen revealed no evidence of malignancy. Before the treatment, the size of the nodules decreased spontaneously by about 50% in one month and significantly in two months. Although combination chemotherapy, which consisted of CHOP, brought her partial remission, she experienced neurological symptoms 6 months after the initial treatment and died of brain metastasis 9 months after the treatment.

Conclusions: This is a unique case for two following reasons: 1) the first biopsy revealed non‐specific findings compatible with erythema nodosum; and 2) before the treatment, the nodules regressed spontaneously. Dermatologists should take multiple skin biopsies for EN lesions with the non‐specific histopathological findings not to refute the existence of this disease.
Restrictive dermopathy: report of a case and review of the literature
Authors: Wesche W. A. , Cutlan R. T. , Khare V. , Chesney T. , Shanklin D.
Published: March 2003

Background: Restrictive dermopathy is a rare autosomal recessive skin disorder that is fatal in the neonatal period. Clinical and pathologic findings are distinctive and allow for a specific diagnosis in most cases.

Methods: We present a case of an affected infant and a review of the previously reported cases in the literature.

Results: The infant had thick shiny skin with reduced compliance and multiple spontaneous linear splits. Additional findings included an abnormal facies with a distinctive small, round and open mouth, low set ears, small nose, widely spaced sutures, flexion contractures of the extremities, and poorly expanded lungs. The infant expired 65 h after birth. Histologic findings of the skin at autopsy included a relatively unremarkable epidermis, a flat dermal‐epidermal junction (absent rete ridges), an overall thinned dermis with hypoplastic appendage structures, a dense fibrotic reticular dermis with collagen parallel to the epidermis, a sharp subcutaneous margin, and an abnormally thick layer of subcutaneous adipose tissue. Electron microscopic findings included dense dermal patches of collagen and fibroblasts with abundant endoplasmic reticulum and unusually small tonofilaments. Review of previously reported cases reveals strikingly consistent findings.

Conclusions: This rare condition illustrates that abnormal cutaneous development may produce fetal hypokinesia, leading to profound effects on intrauterine growth and development. The autosomal recessive pattern of inheritance and morphologic changes of the skin and skeletal system in this disorder suggest that a structural protein or enzyme defect, perhaps of collagen metabolism, may underlie the pathogenesis.
Upregulation of P‐cadherin expression in the lesional skin of pemphigus, Hailey‐Hailey disease and Darier’s disease
Authors: Hakuno Megumi , Akiyama Masashi , Shimizu Hiroshi , Wheelock Margaret J. , Nishikawa Takeji
Published: March 2003

Background: Autoimmune blistering diseases, pemphigus vulgaris (PV) and pemphigus foliaceus (PF), are known to be caused by binding of autoantibodies to the desmosomal cadherins, desmoglein 3 and desmoglein 1, respectively. Recently, mutations in the genes coding Ca2+ pumps leads to inherited blistering diseases, Hailey‐Hailey disease (HHD) and Darier’s disease (DD). Cadherins are a family of Ca2+‐dependent cell adhesion molecules and P‐cadherin is one of the major cadherins expressed in the epidermis. Although detailed mechanisms of acantholysis of these blistering diseases have not been fully clarified, abnormal expression of cadherins caused by altered Ca2+ concentration due to the binding of autoantibodies to cell surface or by mutations in Ca2+ pumps is suggested to be involved in mechanisms of acantholysis of these atuoimmune and inherited blistering diseases. The purpose of the present study was to determine whether altered P‐cadherin expression is present in these diseases.

Method: Distribution patterns of P‐cadherin in skin specimens from patients with PV (n=2), PF (n=2), HHD (n=4) and DD (n=3), were examined with confocal laser scanning microscopy using two anti‐P‐cadherin antibodies, 6A9 and NCC‐CAD‐299.

Results: In normal control skin, P‐cadherin expression was restricted to the basal layer. In contrast, positive immunostaining of P‐cadherin was observed not only in the basal cells, but also in the suprabasal cells in lesional skin of all the acantholytic diseases.

Conclusions: The present results clearly demonstrated that upregulation of P‐cadherin expression occurs in the acantholysis in all the four blistering diseases PV, PF, HHD and DD. Upregulation of P‐cadherin may be involved in the pathomechanism of both the autoimmune blistering diseases and the inherited blistering diseases.
S100A6 preferentially labels type C nevus cells and nevic corpuscles: additional support for Schwannian differentiation of intradermal nevi
Authors: Fullen D. R. , Reed J. A. , Finnerty B. , McNutt N. S.
Published: March 2003

Background: Melanocytic nevi typically show a morphologic sequence of maturation from epithelioid “type A” cells to fusiform, Schwann cell‐like “type C” cells with dermal descent. Nevi may also produce Wagner‐Meissner‐like structures (nevic corpuscles). Previous studies have shown that this maturation of intradermal nevi recapitulates intermediate stages in Schwann cell development. In intradermal nevi, we have evaluated the pattern of S100A6 protein, a form of S100 found in Schwann cells.

Methods: Formalin‐fixed, paraffin‐embedded archival tissues were evaluated by immunohistochemistry using antibodies specific for S100A6 and S100B in 38 intradermal nevi (IDN). Ten neurofibromas (NF), 3 Schwannomas (SCH), 2 palisaded and encapsulated neuromas (PEN), and 2 granular cell tumors (GCT) were included as positive controls since these lesions have large numbers of Schwann cells.

Results: Melanocytic nevi demonstrated preferential anti‐S100A6 staining of “type C” cells (36/38; 28 strong, 8 weak) and nevic corpuscles (25/38; 19 strong, 6 weak) compared to “type A” cells (17/38; 17 weak) and “type B” cells (17/38; 4 strong, 13 weak). All NF, SCH, and PEN stained strongly with anti‐S100A6. Both GCT were negative with anti‐S100A6 but positive with anti‐S100B.

Conclusions: The pattern of S100A6 expression in intradermal nevi further supports the hypothesis that maturation in these lesions recapitulates features of Schwann cell differentiation. The lack of S100A6 expression by both GCT suggests that these lesions have lost this feature of Schwann cells, which may play a role in their peculiar phenotypic appearance.
Recurrent melanocytic nevus: a histologic and immunohistochemical evaluation
Authors: Hoang Mai P. , Prieto Victor G. , Burchette James L. , Shea Christopher R.
Published: March 2003

Background: Recurrent melanocytic lesions may histologically resemble malignant melanoma.

Methods: We evaluated the original nevi (ON) and recurrent nevi (RN) of 15 patients by routine histology and immunohistochemistry (IHC), examining expression of S‐100 protein, gp100 (with HMB‐45), MART‐1, tyrosinase, and the Ki‐67 proliferation marker.

Results: Compared with ON, RN had a dermal scar, a significantly greater number of melanophages, and a greater extent of cellular atypia including prominent nucleoli and larger cell size. Architecturally, RN showed significantly less symmetry than ON; however, the percentage of junctional cohesive nests, the presence of suprabasal spread, and the degree of confluence were similar between ON and RN. Both ON and RN showed a decrease in expression of gp100 and tyrosinase with increasing depth (“maturation gradient”) and low proliferative activity in both the junctional (4.6% for ON vs. 4.13% for RN) and the dermal components (0.93% for ON vs. 1.45% for RN).

Conclusions: RN exhibit a dermal scar, a greater number of melanophages, cytologic atypia, and asymmetry than ON, features that may raise concern about the possibility of malignant melanoma. However, the area with the irregular architectural pattern is restricted to the epidermis and dermis immediately above the scar. In addition, IHC helps to distinguish RN from malignant melanoma; specifically, RN demonstrate an immunohistochemical “maturation pattern” (with HMB‐45 and anti‐tyrosinase) and a low proliferative index (with Ki‐67).
Granulomatous lymphangitis of the scrotum and penis
Authors: Murphy Michael J. , Kogan Barry , Carlson J. Andrew
Published: March 2003

Background: Acquired lymphedema of the genitalia is a rare childhood presentation and is more common in elderly individuals secondary to pelvic/abdomenal malignancy or its therapy or worldwide due to filariasis.

Objective: Herein, we report a case of a healthy 11‐year‐old boy who presented with a 1‐year history of chronic, asymptomatic scrotal and penile swelling. Biopsy revealed edema, lymphangiectases and peri‐ and intralymphatic sarcoidal type granulomas. This histologic pattern of granulomatous lymphangitis is most commonly associated with orofacial granulomatosis (granulomatous cheilitis and Melkersson‐Rosenthal syndrome) and Crohn’s disease. Treatment with topical steroids and physical support has resulted in marked improvement. No systemic disease (Crohn’s disease) is evident 1 year later. Literature review revealed 44 cases of genital lymphedema with non‐infectious granulomas. The majority of these young patients had Crohn’s disease, frequently with anal involvement and a minority, both with and without Crohn’s disease, had orofacial granulomatosis.

Conclusions: Granulomatous lymphangitis should be considered in the differential diagnosis of chronic idiopathic swelling of the genitalia, particularly in younger individuals. Further clinical examination, additional laboratory studies and close follow‐up for co‐existing or subsequent development of Crohn’s disease should be performed. The overlap between granulomatous lymphangitis of the genitalia, Crohn’s disease and orofacial granulomatosis suggest that granulomatous lymphangitis of the genitalia may represent a forme fruste of Crohn’s disease.
Expression of the fibroblast/macrophage marker 1B10 by spindle cells in Kaposi's sarcoma lesions and by Kaposi's sarcoma‐derived tumor cells
Authors:   Thierry Simonart, Degraef Chantale , Heenen Michel , Hermans Philippe , Van Vooren Jean‐Paul , Noel Jean‐Christophe
Published: March 2003

Background:  Kaposi's sarcoma (KS) is a tumor whose ontogenic origin remains a matter of contention. KS tissues are characterized by predominant expression of endothelial markers, while KS‐derived cell cultures are usually characterized by expression of mesenchymal non‐endothelial cell markers.

Aims:  In order to clarify the ontogenic origin of KS cells, we investigated the expression of the fibroblast/macrophage marker 1B10 in KS tissues (AIDS‐associated KS, n = 9; classic KS, n = 6; iatrogenic KS, n = 6) and in KS‐derived cell cultures.

Results:  1B10 was expressed by loosely distributed spindle‐shaped cells in early ‘patch‐stage’ KS and by a variable proportion of spindle cells in late ‘plaque‐ and nodular‐stage’ KS. Using immunohistochemistry and immunoblot analysis, we found that, in vitro, reactivity for 1B10 was uniformly evidenced in fibroblasts and in KS‐derived spindle cell cultures, irrespective of their histological or epidemiological setting. By contrast, vascular smooth muscle cells and endothelial cells were negative for 1B10.

Conclusions:  These results suggest that the KS spindle cells isolated in vitro may represent a particular subpopulation of the KS spindle cell compartment.
Platelet involvement in cutaneous small vessel vasculitis
Authors: Meijer‐Jorna Lorine B. , Mekkes Jan R. , Van Der Wal Allard C.
Published: March 2003

Background:  Secretory products of platelets serve important functions in inflammation and thrombosis. Participation of platelets in the tissue reaction associated with cutaneous small vessel vasculitis has not yet been evaluated, so we systematically investigated the presence of platelet aggregates in inflamed microvessels.

Methods:  Thirty‐six biopsies containing vasculitis and 18 biopsies with perivascular or interface type dermatitis were reviewed and adjacent sections were immunohistochemically stained with anti‐CD61 antibody recognizing GPIIbIIIa receptors on platelets and with anti‐von Willebrand factor (anti‐vWF) antibody.

Results:  Platelet aggregates were observed in 27 (75%) of the vasculitis biopsies and three (16.7%) of the perivascular dermatitis biopsies, of which two (11%) had traumatic vessel damage. In all vasculitis cases, platelet clumps were associated with diffuse immunostaining of the perivascular stroma with the initiator of platelet aggregation anti‐vWF. In the non‐vasculitis type of dermatitis anti‐vWF staining remained strictly limited to the cytoplasm of endothelial cells in 10 cases, and in eight cases there was also slight diffuse perivascular staining, albeit less extensively than in vasculitis cases.

Conclusion:  Formation of platelet aggregates appears to play a thus far unrecognized role in cutaneous small vasculitis. Secretory products of platelets will likely contribute to the inflammatory response and tissue damage in vasculitis. Moreover, platelet immunohistochemistry may be helpful in the diagnosis of microvascular damage in paraffin sections.
Clear cell atypical fibroxanthoma:a clinicopathologic study
Authors: Crowson A. Neil , Carlson‐Sweet Kim , Macinnis Colleen , Taylor James R. , Battaglia Tammy , LaMar Walter L. , Minor David , Sutter Steven , Hill Tamara
Published: March 2003

Introduction: The atypical fibroxanthoma (AFX) is considered by most authorities to represent a superficial or minimally invasive variant of malignant fibrous histiocytoma that most often presents as a solitary nodule on the sun‐exposed skin of the elderly. Among the rarest variants is the clear cell AFX, a lesion which raises consideration to a differential diagnosis encompassing a variety of neoplastic and non‐neoplastic clear cell proliferations.

Methods:  We describe three cases of a distinctive cutaneous neoplasm arising in the sun‐exposed skin of elderly patients. In all cases, formalin‐fixed, paraffin‐embedded tissue was available for analysis. The histology in concert with the immunophenotype was held to be diagnostic of the clear cell variant of AFX.

Results:  All tumors comprised sheets of large cells with foamy cytoplasms and hyperchromatic, polyploid nuclei manifesting frequent and atypical mitoses. The critical cells in our cases expressed CD68 but none of CD3, CD20, CD34, S‐100 protein, muscle‐specific actin, factor XIIIa, Melan‐A, carcinoembryonic antigen, or cytokeratin.

Conclusion:  Although typical examples of AFX provoke diagnostic consideration of spindle cell cancers of the skin (most often spindle cell melanoma, spindle cell squamous cell carcinoma, and leiomyosarcoma), the clear cell variant raises other differential diagnostic considerations instead. These include balloon cell melanoma, sebaceous carcinoma, pleomorphic liposarcoma, chordoma, parachordoma, tricholemmal carcinoma and clear cell squamous cell carcinoma. A diagnosis of AFX is one of exclusion; one must employ immunohistochemical markers to rule out the aforementioned differential diagnostic considerations. By reporting the fifth, sixth and seventh cases of clear cell AFX, we hope to alert dermatopathologists to this distinctive and unusual neoplasm, recognition of which is essential to avoid under‐ or over‐diagnosis and inappropriate therapy.
Problems in the interpretation of apparent ‘radial growth phase’ malignant melanomas that metastasize
Authors: Abramova Liana , L. Slingluff Craig , Patterson James W.
Published: March 2003

Background:  The delineation of radial and vertical growth phases in primary cutaneous malignant melanomas has contributed to our understanding of melanoma progression and has enhanced the ability of pathologists to provide clinicians with meaningful prognostic information. Vertical growth phase (VGP) lesions have the potential to metastasize, but radial growth phase (RGP) melanomas are believed to lack competence for metastasis.

Methods:  We have identified three cases in which metastasis occurred in association with lesions initially interpreted as RGP melanomas. To determine whether these cases truly represented exceptional metastasizing RGP melanomas or VGP lesions incorrectly identified as RGP lesions, careful microscopic re‐review of these cases was performed.

Results:  In one case, additional microscopic sectioning revealed a focus of vertical growth that was not evident on the original sections. In the other two cases, only radial growth was found. In one of these cases there was melanoma in situ with regressive changes, but no evidence for invasive melanoma. In the other, a RGP lesion was associated with an adjacent compound nevus with periadnexal involvement.

Conclusions: These cases suggest that, while true RGP melanomas have an excellent prognosis, caution must be exercised in defining a lesion as having no metastatic potential when multiple sections of the primary lesion are unavailable, when the lesion is accompanied by regressive changes, or when there is an associated melanocytic nevus. It is possible that strictly defined RGP melanomas may metastasize in very rare cases. Our observations also suggest that metastatic potential is a function of numerous factors, and may not be evaluable on morphological grounds alone.
Langerhans cell microgranulomas (pseudo‐pautrier abscesses): morphologic diversity, diagnostic implications and pathogenetic mechanisms
Authors: Burkert Kelly L. , Huhn Karen , Whitaker Menezes Diana , Murphy George F.
Published: March 2003

The term ‘Langerhans cell microgranuloma’ (LCM) was introduced a decade ago to draw attention to focal collections of these cells within the epidermal layer that develops during certain immune reactions. In spite of a growing awareness of this phenomenon during the past decade, few reports have focused on the development and phenotype of LCM. In this commentary, we review the historical development of the concept of LCM, demonstrate the salient immunomorphologic characteristics of LCM, and advance a hypothesis to explain their sequential evolution and formation.
Dental anxiety among Israeli dental students: a 4‐year longitudinal study
Authors: Peretz Benjamin , Mann Jonathan
Published: March 2003

The aims of the present study were (a) to evaluate students’ estimation of their parents’ dental anxiety; (b) to measure students’ dental anxiety and to study their ranking of the most fear provoking stimuli in the dental situation during their pre‐clinical and clinical years; (c) to investigate gender differences among students with regard to dental anxiety. 30 3rd‐year students (15 male and 15 female) who completed a 4‐section questionnaire which requested sociodemographic information, evaluation of parents’ dental anxiety, dental anxiety scale (DAS) and dental fear scale (DFS), completed the DAS and DFS in their 5th and 6th years. Both male and female students estimated their mothers’ dental anxiety as significantly higher than their fathers’. Female students ranked their parents higher than males. DAS scores were significantly higher among female students than among males in the 3rd year. However, DAS scores were reduced from the 3rd to the 6th year among the total class and significantly among females, while males’ levels of anxiety remained within close range throughout the years. The dental anxiety scores of all students who experienced a dental procedure in the past were higher than the scores of the students who did not. The most fearful stimulus was ‘feeling the needle’. Our findings may suggest that the change in the reported dental anxiety of the students during the years of dental studies in the present study may be explained by the increased professional education and clinical experience that the students acquire throughout their studies in the dental school. Being exposed to basic trivial dental procedures (such as local anaesthetic injection) may help students either to be habituated or to use rational coping strategies when dealing with personal dental experience.
A comparison between videotaped and live demonstrations, for the teaching of removable partial denture procedures
Authors: Packer M. E. , Rogers J. O. , Coward T. J. , Newman P. S. , Wakeley R.
Published: March 2003

Aim: This study was devised to test the effectiveness of videotaped demonstrations as opposed to live demonstrations, to small groups of undergraduate dental students. The outcome was assessed by comparing the students' understanding of the clinical and laboratory technical stages of the altered cast impression technique, which is used in the construction of removable partial dentures.

Method: 31 students watched a series of videotaped demonstrations and 30 received a similar series of live demonstrations. The altered cast procedure was divided into 5 distinct stages, each of which was assessed with the aid of agreed criteria, initially by the students and then by 2 staff assessors and these results were compared. The students were subsequently asked to rate how helpful the videotaped or live demonstration had been on a 5‐point scale.

Results: The live demonstration group showed better agreement between the students' assessment and the assessors' assessment of the quality of the work for the first part of the clinical stage. There was no difference in the groups' assessment of the final outcome of this clinical stage and the subsequent laboratory technical stages. Students who observed the live demonstrations indicated higher scores for its helpfulness in performance of all the stages of the technique, when compared to those who had observed a videotaped demonstration.

Conclusion: Both teaching methods developed a similar level of understanding of the principles behind the exercise, although the students preferred the live demonstrations. A carefully produced videotaped demonstration can be a useful alternative to a live demonstration in teaching the short and clear cut technique selected for this study.
Students' evaluation of online course materials in Fixed Prosthodontics: a case study
Authors: Pilcher Elizabeth S.
Published: March 2003

Purpose: The purpose of this study was to assess a new online course format for dental students. Preclinical Fixed Prosthodontics I is a didactic and laboratory course given in the first year of the dental school curriculum. In the spring semester of 1999, the didactic portion of the course was offered in a web‐based format as a supplement to the traditional lecture format.

Methods: The study population was 53 first year dental students at one school. The study design was a one group post test without a control group. The online questionnaire consisted of multiple choice questions, Leikert scale questions and open‐ended questions. Data were collected using Filemaker Pro and analyzed using EpiInfo.

Results: Student response rate was 96% (52/53). All of the students responded that they felt comfortable with their computer skills in utilizing this course format. Most (96%) responded that the online materials were either very helpful or helpful to them. About half, (54%) recommended that the online format be continued as a supplement to traditional lectures, while 28% recommended replacing traditional lectures with the new format in order to provide more laboratory time in the course. The syllabus, lecture materials, bulletin board and handouts were found to be the most helpful online features. The least helpful features were the listserve, decision tree, and e‐mail options. Most frequently mentioned strengths of the online material were listed as 1) the ability to view material at their own pace and at a time convenient to them, 2) quality photographs in lecture materials and 3) online quizzes. Weaknesses of the course were ranked by students as 1) problems with access to the materials and the intranet system, 2) taking quizzes online and 3) difficulty in printing the web‐based lecture materials.

Conclusions: The delivery of web‐based material as a course supplement in Fixed Prosthodontics I was determined to be an overall success. Fine tuning of problems with access to the materials took place throughout the course. The student feedback will help direct future development of web‐based course materials in the dental school curriculum.
Replacement of the native crayfish Astacus astacus by the introduced species Pacifastacus leniusculus in a small, enclosed Finnish lake: a 30‐year study
Authors: Westman Kai , Savolainen Riitta , Julkunen Markku
Published: March 2003

The native noble crayfish Astacus astacus L., and the introduced North American signal crayfish Pacifastacus leniusculus Dana, co‐occur in Slickolampi, a small lake in southern Finland. That both species have lived side‐by‐side for 30 yr without any signs of crayfish plague Aphanomyces astaci, indicates that the P. leniusculus population must be plague‐free. According to annual trap catches and population size estimates, A. astacus was clearly dominant in the 1970s and most of the 1980s. At the end of the 1980s, however, there was a shift in the relative abundances of the two species, and in the 1990s, P.leniusculus became dominant. As the 1990s drew to a close, it accounted for >98% of total catches. Originating from a minor stocking (only 900 2nd stage juveniles) P. leniusculus has not augmented the existing fauna in this lake but has almost completely replaced A. astacus. Both species seem to a great extent to prefer the same types of biotope but P. leniusculus is distinctly more demanding and was encountered less often than A. astacus on gently‐sloping soft shores. The proportion of A. astacus with chelae injuries (16 yr, mean 17.3%) was nearly twice that of P. leniusculus (9.3%), suggesting that agonistic interspecific encounters do occur and that P. leniusculus is much more competitive. However, the consistent weakening of A. astacus, even at sites with only a low density of P. leniusculus, indicates that the elimination of A. astacus is not adequately explained by competitive exclusion. We suggest that its disappearance is governed by a combination of several interacting mechanisms, of which harvest (≥100 mm specimens of both species) and interspecific competition with P.leniusculus were initially the main reasons for the decline in the population. The ultimate reason for the collapse of A. astacus seems to have been the almost complete cessation of successful reproduction, presumably due to reproductive interference between the two species. Interspecific mating results in females laying sterile eggs. Although both species suffer from the ensuing loss of recruitment, the consequences are less serious for P. leniusculus, which has a higher capacity for population increase than A. astacus: the smaller the proportion of A. astacus, the greater the role played by reproductive interference as a replacement mechanism.
Patterns of parasite species richness of Western Palaeartic micro‐mammals: island effects
Authors: De Bellocq Joëlle Goüy , Morand Serge , Feliu Carlos
Published: March 2003

We investigate the patterns of parasite species richness of small mammals of the Western Palaearctic, and the effects of insularity. We compiled 28 studies dealing with 16 species of mammals. There was a significant effect of area size on the total parasite species richness, controlling for host sample size. Four mammal species were sufficiently sampled. Two are associated with humans: Mus musculus, and Rattus rattus, and two are not associated with humans, Apodemus sylvaticus and Clethrionomys glaerolus. We show that there is an effect of insularity on parasite species richness of A. sylvaticus. Rodents associated with humans show no effect of insularity on parasite species richness. These rodents appear to reflect a more complex pattern of parasite species richness, probably because of their close association with humans. Host specificity of parasites significantly decreases on islands, with the exception of Rattus rattus. We use parasitological data in order to explore the geographical connections between host populations. We show that parasites may help to resolve these connections but we emphasise that parasites are better geographic than phylogenetic markers.
Effects of forest edge on populations of white‐footed micePeromyscus leucopus
Authors: Wolf Mosheh , Batzli George O.
Published: March 2003

Several studies have reported higher densities of white‐footed mice in small fragments than in large fragments of eastern deciduous forests. The edge hypothesis states that higher densities in smaller fragments reflect an increase in relative amount of edge habitat, which supports higher densities of mice because of its higher quality. To test this hypothesis we live trapped white‐footed mice along edge‐to‐interior gradients in forest fragments of east‐central Illinois. Our results indicated a greater abundance of mice in the forest interior than near the edge, which did not support the edge hypothesis. This pattern could occur because dominant adults hold larger territories of higher quality habitat, thereby reducing density and increasing fitness near the edge (an ideal despotic distribution). We found some evidence of increased reproductive success (juveniles per female) at the edge, but this could reflect density‐dependent demographic processes rather than habitat quality. Furthermore, other indicators of dominance (body weight, and reproductive activity) did not show an increase at the edge, and other studies indicate higher prevalence of natural enemies at edges, which could account for lower densities there. Reduced competition from larger rodents and reduced predation could cause higher densities in small fragments but the distributions of competitors and predators do not strongly support these hypotheses. We suggest two additional hypotheses that could account for greater densities in smaller fragments: 1) estimates of high densities could be artifacts of the large effect that a few captures can have on density estimates for very small fragments, and 2) densities in smaller fragments are overestimated because mice use a relatively larger area of surrounding habitat as fragment size decreases.
Exotic plant invasions over 40 years of old field successions: community patterns and associations
Authors: Meiners Scott J. , Pickett Steward T. A. , Cadenasso Mary L.
Published: March 2003

While exotic plant species often come to dominate disturbed communities, long‐term patterns of invasion are poorly known. Here we present data from 40 yr of continuous vegetation sampling, documenting the temporal distribution of exotic plant species in old field succession. The relative cover of exotic species decreased with time since abandonment, with significant declines occurring ≥20 yr post‐abandonment. The number of exotic species per plot also declined with time since abandonment while field‐scale richness of exotics did not change. This suggests displacement occurring at small spatial scales. Life history types changed from short‐lived herbaceous species to long‐lived woody species for both native and exotic plant species. However, shrubs and lianas dominated woody cover of exotic plants while trees dominated native woody cover. The species richness of exotic and native species was positively correlated at most times. In abandoned hay fields, however, the proportion of exotic plant cover per plot was inversely related to total species richness. This relationship suggests that it is not the presence, but the abundance of exotic species that may cause a reduction in community diversity. While the development of closed‐canopy forest appears to limit most introduced plant species, several shade‐adapted exotic species are increasing within the fields. These invasions may cause a reversal of the patterns seen in the first 40 yr of succession and may result in further impacts on community structure.
Integrating the statistical analysis of spatial data in ecology
Authors: Liebhold A. M. , Gurevitch J.
Published: March 2003

In many areas of ecology there is an increasing emphasis on spatial relationships. Often ecologists are interested in new ways of analyzing data with the objective of quantifying spatial patterns, and in designing surveys and experiments in light of the recognition that there may be underlying spatial pattern in biotic responses. In doing so, ecologists have adopted a number of widely different techniques and approaches derived from different schools of thought, and from other scientific disciplines. While the adaptation of a diverse array of statistical approaches and methodologies for the analysis of spatial data has yielded considerable insight into various ecological problems, this diversity of approaches has sometimes impeded communication and retarded more rapid progress in this emergent area. Many of these different statistical methods provide similar information about spatial characteristics, but the differences among these methods make it difficult to compare the results of studies that employ contrasting approaches. The papers in this mini‐series explore possible areas of agreement and synthesis between a diversity of approaches to spatial analysis in ecology.
Abundance and species richness as a function of food resources and vegetation structure: juvenile fish assemblages in rivers
Authors: Grenouillet Gaël , Pont Didier , Seip Knut L.
Published: March 2003

Availability of food and habitat complexity are two factors generally invoked to explain the high density of fish in vegetated habitats. The role of food resources (zooplankton) and habitat complexity (expressed by a vegetation structural index) in determining juvenile fish abundance and fish species richness in three morphologically contrasted macrophyte types (Sagittaria, Ceratophyllum and Nuphar) was studied for a large, lowland river.

 Our results showed that fish abundance increased with food availability, and was maximal for intermediate values of vegetation complexity. Food resources and vegetation complexity did not, however, explain the higher juvenile fish abundance observed in Sagittaria beds. We suggested that plant growth form, acting on fish foraging success and risk of predation, might influence patterns of juvenile fish distribution.  Species‐abundance relationships were similar among the three macrophyte types, but relationships between number of fish species (fish richness) and number of samples differed. Fish richness in terms of total number of fish species found at each sampling point showed the same pattern as for fish abundance: it increased with food availability and was highest at intermediate vegetation complexities. However, since both fish abundance and fish richness responded in the same manner to food availability and vegetation complexity, we were not able to distinguish statistically any effect for the specific fish richness formulated by the number of fish species per unit fish abundance. The current paradigm that structural complexity of vegetation provides a wider range of niches, increasing species diversity, was thus not verified. This finding indicates a simple species‐abundance relationship (the passive sampling hypothesis), and suggests that no special mechanism acts directly on fish species richness.