Knock down analysis reveals critical phases for specific oskar noncoding RNA functions during Drosophila oogenesis

The oskar transcript, acting as a noncoding RNA, contributes to a diverse set of pathways in the Drosophila ovary, including karyosome formation, positioning of the microtubule organizing center (MTOC), integrity of certain ribonucleoprotein particles, control of nurse cell divisions, restriction of several proteins to the germline, and progression through oogenesis. How oskar mRNA acts to perform these functions remains unclear. Here, we use a knock down approach to identify the critical phases when oskar is required for three of these functions. The existing transgenic shRNA for removal of oskar mRNA in the germline targets a sequence overlapping a regulatory site bound by Bruno1 protein to confer translational repression, and was ineffective during oogenesis. Novel transgenic shRNAs targeting other sites were effective at strongly reducing oskar mRNA levels and reproducing phenotypes associated with the absence of the mRNA. Using GAL4 drivers active at different developmental stages of oogenesis, we found that early loss of oskar mRNA reproduced defects in karyosome formation and positioning of the MTOC, but not arrest of oogenesis. Loss of oskar mRNA at later stages was required to prevent progression through oogenesis. The noncoding function of oskar mRNA is thus required for more than a single event.

Different roles for the adjoining and structurally similar A-rich and poly(A) domains of oskar mRNA: Only the A-rich domain is required for oskar noncoding RNA function, which includes MTOC positioning

Drosophila oskar (osk) mRNA has both coding and noncoding functions, with the latter required for progression through oogenesis. Noncoding activity is mediated by the osk 3' UTR. Three types of cis elements act most directly and are clustered within the final ~120 nucleotides of the 3' UTR: multiple binding sites for the Bru1 protein, a short highly conserved region, and A-rich sequences abutting the poly(A) tail. Here we extend the characterization of these elements and their functions, providing new insights into osk noncoding RNA function and the makeup of the cis elements. We show that all three elements are required for correct positioning of the microtubule organizing center (MTOC), a defect not previously reported for any osk mutant. Normally, the MTOC is located at the posterior of the oocyte during previtellogenic stages of oogenesis, and this distribution underlies the strong posterior enrichment of many mRNAs transported into the oocyte from the nurse cells. When osk noncoding function was disrupted the MTOC was dispersed in the oocyte and osk mRNA failed to be enriched at the posterior, although transport to the oocyte was not affected. A previous study did not detect loss of posterior enrichment for certain osk mutants lacking noncoding activity (Kanke et al., 2015). This discrepancy may be due to use of imaging aimed at monitoring transport to the oocyte rather than posterior enrichment. Involvement in MTOC positioning suggests that the osk noncoding function may act in conjunction with genes whose loss has similar effects, and that osk function may extend to other processes requiring those genes. Further characterization of the cis elements required for osk noncoding function included completion of saturation mutagenesis of the most highly conserved region, providing critical information for evaluating the possible contribution of candidate binding factors. The 3'-most cis element is a cluster of A-rich sequences, the ARS. The close juxtaposition and structural similarity of the ARS and poly(A) tail raised the possibility that they comprise an extended A-rich element required for osk noncoding function. We found that absence of the poly(A) tail did not mimic the effects of mutation of the ARS, causing neither arrest of oogenesis nor mispositioning of osk mRNA in previtellogenic stage oocytes. Thus, the ARS and the poly(A) tail are not interchangeable for osk noncoding RNA function, suggesting that the role of the ARS is not in recruitment of Poly(A) binding protein (PABP), the protein that binds the poly(A) tail. Furthermore, although PABP has been implicated in transport of osk mRNA from the nurse cells to the oocyte, mutation of the ARS in combination with loss of the poly(A) tail did not disrupt transport of osk mRNA into the oocyte. We conclude that PABP acts indirectly in osk mRNA transport, or is associated with osk mRNA independent of an A-rich binding site. Although the poly(A) tail was not required for osk mRNA transport into the oocyte, its absence was associated with a novel osk mRNA localization defect later in oogenesis, potentially revealing a previously unrecognized step in the localization process.

Sub-lethal coral stress: detecting molecular responses of coral populations to environmental conditions over space and time

In order for sessile organisms to survive environmental fluctuations and exposures to pollutants, molecular mechanisms (i.e. stress responses) are elicited. Previously, detrimental effects of natural and anthropogenic stressors on coral health could not be ascertained until significant physiological responses resulted in visible signs of stress (e.g. tissue necrosis, bleaching). In this study, a focused anthozoan holobiont microarray was used to detect early and sub-lethal effects of spatial and temporal environmental changes on gene expression patterns in the scleractinian coral, Montastraea cavernosa, on south Florida reefs. Although all colonies appeared healthy (i.e. no visible tissue necrosis or bleaching), corals were differentially physiologically compensating for exposure to stressors that varied over time. Corals near the Port of Miami inlet experienced significant changes in expression of stress responsive and symbiont (zooxanthella)-specific genes after periods of heavy precipitation. In contrast, coral populations did not demonstrate stress responses during periods of increased water temperature (up to 29°C). Specific acute and long-term localized responses to other stressors were also evident. A correlation between stress response genes and symbiont-specific genes was also observed, possibly indicating early processes involved in the maintenance or disruption of the coral-zooxanthella symbiosis. This is the first study to reveal spatially- and temporally-related variation in gene expression in response to different stressors of in situ coral populations, and demonstrates that microarray technology can be used to detect specific sub-lethal physiological responses to specific environmental conditions that are not visually detectable.

A surreptitious sinister sarcoma

Angiosarcoma is an exceedingly rare endothelial-derived sarcoma that, when seen, usually presents as an expanding bruise-like patch or violaceous papule/nodule on the head of an elderly patient. Herein, we present the histologic features of an unusual case that defied initial diagnosis.

Dermal atypical lipomatous tumor/well-differentiated liposarcoma obfuscated by epidermal inclusion cyst: a wolf in sheep's clothing?

Epidermal inclusion cysts are an exceedingly common entity seldom seen in association with a malignant tumor. Herein, we report a unique case of an epithelial inclusion cyst seen in association with an atypical lipomatous tumor/well-differentiated liposarcoma. The epidermal inclusion cyst was delimited to the dermis and circumferentially enveloped by an atypical adipocyte tumor containing myxoid foci and comprised of lipoblasts. This case underscores the importance of scrutinizing the entirety of cysts and other ostensibly trivial dermal entities to avoid the pitfall of misdiagnosing a potentially serious tumor.

Benign lichenoid keratosis: a clinical and pathologic reappraisal of 1040 cases

Benign lichenoid keratosis, otherwise known as lichen planus-like keratosis, is a common, cutaneous entity that is often confused with cutaneous malignancy. Few studies have examined the multiple clinical and pathologic guises of this entity, particularly within the context of clinical pathologic correlation or magnitude of this study. We examined the epidemiologic, clinical, and pathologic attributes of 1040 consecutive cases of benign lichenoid keratosis referred for pathologic examination at a busy laboratory over an entire year. Clinical parameters assessed included the age, anatomic location, gender, and multiplicity of the lesions. Pathologic attributes were assessed yielding discernment of five different subtypes that included a classic type, bullous type, atypical type with cytologically atypical lymphocytes, an early or interface type, and a late regressed or atrophic type. The results yielded an average age at presentation of 59.5 years with an age range of 36 to 87 years. The gender frequency was 76% female, 24% male. The trunk was the most common location (76%), followed by the extremities (33%) and head and neck (7%); 8% of patients presented with two lesions and less than 1% with three lesions prompting consideration of lichen planus. The classic, atypical, and bullous forms of the disease clinically presented with erythematous papule/plaque(s). The early or interface type showed erythematous to hyperpigmented brown macules and the regressed or atrophic type presented as violaceous papules or irregularly distributed macular pigmentation; 81% of the lesions showed the classic histology consisting of epidermal acanthosis with a band-like lichenoid lymphocytic infiltrate. Variable numbers of plasma cells, eosinophils, and neutrophils were identified as well as epidermal parakeratosis distinguishing these lesions from typical lichen planus. The bullous variant showed intraepidermal or subepidermal bullous cavities with a dense associated lymphocytic infiltrate and increased numbers of necrotic basilar layer keratinocytes. The atypical variant showed features of the classic type with scattered enlarged CD-3, CD-30 (+) lymphocytes possessing hyperchromatic, irregular nuclei. The early interface type showed single lymphocytes aligned along the dermoepidermal junction without epidermal acanthosis and adjacent lentigo. The regressed or atrophic variant showed epidermal atrophy with papillary dermal scarring, patchy lymphocytic infiltrates and melanin incontinence. The clinicopathologic spectrum of benign lichenoid keratosis is broad and encompasses several unrelated entities. An awareness of its expanded presentation is essential to avoid misdiagnosis and may serve as an important forerunner of pathogenic discernment.

Establishment and characterization of a new mantle cell lymphoma cell line, Mino

Mantle cell lymphoma (MCL) is a distinct type of B-cell non-Hodgkin's lymphoma characterized by cyclin D1 overexpression and the cytogenetic abnormality, the t(11;14)(q13;q32). MCL cell lines have been difficult to establish and in vitro studies of these neoplasms are scarce. We describe the establishment and characteristics of a new MCL cell line, Mino. The cells are large, growing singly and in small clumps in vitro. By flow cytometry, the immunophenotype was compatible with MCL (i.e. CD5+CD20+CD23-FMC7+). Conventional cytogenetics showed hyperdiploidy with multiple complex karyotypic abnormalities, but no evidence of the t(11;14), proven to be present only by fluorescence in situ hybridization and polymerase chain reaction (PCR) methods. Western blots showed expression of cyclin D1 but no detectable cyclin D2 and cyclin D3; the retinoblastoma protein was predominantly phosphorylated. There was expression of tumor suppressor gene products including p53, p16(INK4a), and p21(WAF1). Sequencing of the TP53 gene revealed a mutation (codon 147(valine-->glycine)) in exon 5. Epstein Barr virus was absent. In summary, Mino is a new MCL cell line that may be useful to study the pathogenesis of MCL.

Cutaneous indeterminate cell histiocytosis: a new spindle cell variant resembling dendritic cell sarcoma

BACKGROUND

Cutaneous indeterminate cell histiocytosis is a rare neoplastic disorder. Its varied histological presentation and rarity have limited efforts to determine its pathogenic relationship with other histiocytic lesions and possibly, its recognition.

METHODS

We report on an unusual histologic pattern of indeterminate cell histiocytosis that resembled follicular dendritic sarcoma. A battery of immunohistochemical stains and electron microscopy were performed to elucidate the phenotype of the "histiocytic" cells. Based on a review of the literature, reported cases of indeterminate cell histiocytosis are presented and the diagnostic differential of spindle-cell lesions is discussed.

RESULTS

Spindling histiocytes were positive for S-100 and CD1a. The monocytic/macrophage marker, CD68, and the dendritic cell marker, CD21, were negative. Electron microscopy failed to reveal Birbeck granules.

CONCLUSIONS

Relatively few reports of indeterminate cell histiocytosis exist, some of which include discussion of potential overlaps with the non-X histiocytoses. Although the presence of prominent spindling in our case expanded the differential to include non-histiocytic disorders, the identified histiocytes unequivocally fulfilled the criteria of S-100 and CD1a positivity without demonstrable Birbeck granules.

Disseminated acanthamoebiasis presenting as lobular panniculitis with necrotizing vasculitis in a patient with AIDS

BACKGROUND

Disseminated acanthamoebiasis is a rare entity, almost exclusively occurring in the immunocompromised host.

METHODS

We report an unusual case of a 35-year-old female with recurrent sinusitis and multiple skin nodules demonstrating a necrotizing panniculitis, shown to be due to disseminated acanthamoebiasis.

RESULTS

Histologic sections showed a neutrophilic lobular panniculitis with 20- to 30-microm trophozoites consistent with Acanthamoeba species.

CONCLUSIONS

A review the literature shows that the histopathological presentation of acanthamoebiasis often eludes initial diagnostic attempts and that central nervous system (CNS) involvement is frequent and ultimately fatal. When amoebiasis is suspected, knowledge of the trophozoite and cyst forms may be helpful in distinguishing Acanthamoeba species from Entamoeba histolytica.

Developing the Vascular Quality of Life Questionnaire: a new disease-specific quality of life measure for use in lower limb ischemia

AIMS

The purpose of this study was to develop and validate an easily used disease-specific quality of life (QOL) measure for patients with chronic lower limb ischemia and to design an evaluative instrument, responsive to within-subject change, that adds to clinical measures of outcome when comparing treatment options in the management of lower limb ischemia.

METHODS

The first phase consisted of item generation, item reduction, formulating, and pretesting in patients with ischemia. The proportion of patients who selected an item as troublesome and the mean importance they attached to it were combined to give a clinical impact factor. Items with the highest clinical impact factor were used to formulate a new 25-item questionnaire that was then pretested in 20 patients with lower limb ischemia. In the second phase, reliability, validity, and responsiveness of the new questionnaire were assessed in 39 patients with lower limb ischemia who were tested at 0 and 4 weeks. The King's College Hospital's Vascular Quality of Life Questionnaire and the Short-Form 36 were administered at each visit, and treadmill walking distance and ankle/brachial pressure indices were recorded. The new questionnaire's reliability, internal consistency, responsiveness, and validity were determined.

RESULTS

Areas of QOL impairment were consistent through the ranges of disease severity and age, with no apparent differences between the men and women. Therefore, a single questionnaire is applicable to all patients with chronic lower limb ischemia. In stable patients test-retest scores demonstrated a reliability of r more than 0.90. Each item had internal consistency (item-domain Cronbach alpha =.7-.9). The questionnaire was responsive to change, with correlation between change in the questionnaire's total score and both global and clinical indicators of change (P <.001). The questionnaire showed face and construct validity.

CONCLUSIONS

This disease-specific questionnaire is reliable, responsive, valid, and ready for use as an outcome measure in clinical trials. It is sensitive to the concerns of patients with lower limb ischemia, offering a simple method to measure the effect of interventions on their QOL.

Assessing coral stress responses using molecular biomarkers of gene transcription

We present a method for detecting rapid changes in coral gene expression at the messenger ribonucleic acid (mRNA) level. The staghorn coral Acropora cervicornis was exposed to 1 and 10 microg/L permethrin and 25 and 50 microg/L copper for 4 h. Using differential display polymerase chain reaction (PCR), mRNA associated with each toxicant exposure were reverse transcribed into complementary DNA (cDNA) fragments that were subsequently amplified and isolated. Six differentially expressed cDNA fragments were further developed into molecular probes that were used in Northern dot blots to determine the change in transcription levels of target transcripts. Changes in mRNA abundance were quantified by densitometry of chemiluminescence of digoxigenin-labeled probes hybridizing to target mRNA transcripts. The six gene probes showed varying degrees of sensitivity to the toxicants as well as specificity between toxicants. These probes were hybridized in Southern blots to genomic DNA from A. formosa sperm, which lacks zooxanthellae, to demonstrate that the genes coding for the mRNA transcripts produced are found within the coral genome. The gene probes developed in this study provide coral biologists with a new tool for coral assessment. Gene probes are sensitive, toxicant-specific biomarkers of coral stress responses with which gene sequence information can be obtained, providing a mechanism for identifying the stressor altering the gene expression.

Expression of the caveolins in dermal vascular tumors

INTRODUCTION

Histopathologic criteria are usually sufficient for the accurate distinction of benign from malignant dermal vascular tumors. A minority of cases, however, pose a vexing diagnostic dilemma. Recent studies suggest that caveolin, a scaffolding cell membrane protein, may prove helpful in predicting the biologic behavior of endothelial-derived neoplasms.

METHODS

We analyzed a series of 30 dermal vascular tumors including 12 lobular capillary hemangiomas (LCH), 4 cases of targetoid hemosiderotic hemangiomas (TH), 4 cases of tufted angioma (TA), 12 cases of Kaposi's sarcoma (KS), 4 epithelioid (EH) and 1 spindle cell hemangioendothelioma (SH), and 4 cases of angiosarcoma (AS). The distribution of immunoreactivity was analyzed by quantifying cell membrane staining in each case.

RESULTS

There was a statistically significant difference in the expression of caveolin between LCH (mean labeling index=91.6), TH (mean labeling index=89.7), and TA (mean labeling index=87.2) and the cases of KS (mean labeling index=21.6, EH mean labeling index= 23.1), and the AS (mean labeling index=6.3).

CONCLUSIONS

These results indicate that antibodies to caveolin may be useful in separating benign and malignant dermal vascular tumors and possibly implicates this peptide in their pathogenesis.

Fibromucinous T-cell lymphoma: a new clinicopathologic variant of mycosis fungoides?

We report a case of mycosis fungoides associated with extensive dermal fibrosis and mucin deposition. The patient developed indurated plaques with diffuse tightening of the skin reminiscent of the sclerosing disorder scleromyxedema, which was later associated with nodules and lymphadenopathy. Skin biopsies showed diffusely thickened collagen bundles in the dermis and mucin deposition with a dense infiltrate of atypical lymphocytes with an immunophenotypic pattern indicative of mycosis fungoides. In our opinion, these clinical and histopathologic features are unusual for mycosis fungoides and can be construed as a distinct fibromucinous variant. Alternatively, this may represent a fibrosing reaction pattern similar to that described with systemic T- and B-cell lymphomas or a variety of inflammatory disorders.

Cutaneous epithelioid malignant nerve sheath tumor with rhabdoid features: a histologic, immunohistochemical, and ultrastructural study of three cases

INTRODUCTION

Malignant rhabdoid tumors are morphologically defined as sheets of loosely cohesive cells with eccentric nuclei and hyaline, paranuclear inclusions. Although originally described as a distinctive renal neoplasm of childhood, these tumors have since been described in all age groups and in a variety of extrarenal sites. In the latter setting, it is thought that the rhabdoid phenotype is comprised of histogenetically unrelated tumors, that regardless of histogenesis, pursue a biologically aggressive behavior.

METHODS

We report on the clinical, histologic, immunophenotypic, and ultrastructural characteristics of three cases of cutaneous malignant rhabdoid tumor.

RESULTS

Each of the cases arose on the trunk or the extremity of elderly men. None of the patients had neurofibromatosis. All of the lesions histologically showed sheets of loosely cohesive polygonal cells with eccentric nuclei and hyaline paranuclear inclusions. Each of the cases showed the following immunophenotype: S-100 (+), synaptophysin(+), vimentin (+), alpha smooth muscle actin (-), CD-30 (-), HMB-45 (-), and pankeratin(-). Ultrastructure of two of the cases yielded similar results showing paranuclear filamentous aggregates of intermediate filaments, cell membrane dense plaques, and rudimentary cell junctions consistent with nerve sheath differentiation. Tonofilaments, dense bodies, microtubules, neurosecretory granules, and melanosomes were not identified. Each of the patients died of widely metastatic disease within 1 year of diagnosis.

CONCLUSIONS

Cutaneous epithelioid malignant nerve sheath tumor is a potentially aggressive tumor capable of showing rhabdoid differentiation thus simulating a variety of neoplasms. Immunophenotyping and ultrastructural analysis reliably discriminates these lesions from melanoma, de-differentiated carcinoma, lymphoma, and rhabdomyosarcoma.

Solitary fibrous tumors are immunophenotypically distinct from mesothelioma(s)

INTRODUCTION

Solitary fibrous tumor is a soft tissue tissue tumor of unknown histogenesis. Based upon histologic similarities and CD-34 expression, it has been suggested that these neoplasms bear some relationship to mesothelioma, and may represent its extra-pleural equivalent.

METHODS

In order to further investigate this possible relationship, we examined a series of five dermal and five extra-cutaneous solitary fibrous tumors with antibodies directed against the mesothelial markers calretinin and HBME-1.

RESULTS

All the lesions failed to stain with the antibodies tested. This suggests that despite some similar histologic and immunophenotypic features, these lesions are not immunophenotypically identical. Mesotheliomas are CD-34(+), calretinin(+), HBME-1(+), while solitary fibrous tumors are CD-34(+), calretinin(-), HBME-1(-).

CONCLUSIONS

The histogenesis of solitary fibrous tumor remains elusive. It is unlikely that tumor location or tumor de-differentiation accounts for the dichotomous staining properties, as these neoplasms show a similarly benign histologic appearance regardless of location.

Cocaine increases beta-myosin heavy-chain protein expression in cardiac myocytes

BACKGROUND

As many as 47% of chronic cocaine users develop cardiac ventricular hypertrophy. The presence and degree of cocaine-induced ventricular hypertrophy is not correlated with the use of other substances of abuse such as alcohol or cigarettes. Moreover, this hypertrophy occurs in individuals without sustained increases in arterial blood pressure or heart rate, or increases in the plasma concentration of renin, aldosterone, norepinephrine, or cortisol. Therefore, we investigated whether cocaine, in concentrations commonly found in cocaine users, has any direct effects on the protein content in cardiac ventricular myocytes. We compared the effects of cocaine with norepinephrine, which increases the total protein content, especially beta-myosin heavy-chain contractile protein (beta-MHC), in cardiac ventricular myocytes.

METHODS

Experiments were performed on 30-day-old rat ventricular myocytes suspended in culture media and cultured in flasks. In 12 suspension-culture experiments, cocaine or norepinephrine, in doses of 0 (control) or 10(-6) mol/L was added to each culture and the cells were harvested on day 5. In 16 flask-culture experiments, cocaine or norepinephrine was added to each culture on day 7 in doses of 0 (control-vehicle), 10(-7), or 10(-6) mol/L and the cells were harvested on day 10. The total protein content and the myosin protein expression of the myocytes in each culture were determined. Juvenile and adult rat cardiac myosin protein is predominately alpha-myosin heavy-chain protein (alpha-MHC), whereas beta-MHC occurs primarily in fetal rat hearts.

RESULTS

In the suspension-culture experiments, cocaine, 10(-6) mol/L, increased the cardiomyocyte total protein concentration by 29% +/- 2% (P <.001) and the beta-MHC expression by 81% +/- 10% (P <.01) in comparison with the control myocytes. Cocaine slightly decreased cardiomyocyte alpha-MHC. Norepinephrine increased the total protein concentration by 21% +/- 3% (P <.001) and the beta-MHC expression by 59% +/- 10% (P <.01), but did not increase alpha-MHC expression. In the flask-culture experiments, cocaine, 10(-6) mol/L, maximally increased the total protein concentration by 28% (P <.001), the protein/cell ratio by 57% +/- 10% (P <.01), and the beta-MHC expression by 85% +/- 8% (P <.01). Cocaine slightly decreased alpha-MHC. Norepinephrine, 10(-6) mol/L, maximally increased the total protein concentration by 35%, the protein/cell ratio by 63% +/- 9% (P <.01), and the expression of beta-MHC by 78% +/- 11% (P <. 01). Norepinephrine did not increase alpha-MHC expression. In 18 separate flask-culture experiments, cocaine, 10(-6) mol/L, was added to the cardiomyocyte cultures after the addition of phentolamine (n = 9), in concentrations of 10(-7) to 10(-5) mol/L, or metoprolol (n = 9), in concentrations of 10(-7) to 10(-5) mol/L. Neither phentolamine nor metoprolol inhibited the cocaine-induced increase in cardiomyocyte total protein content or the expression of beta-MHC.

CONCLUSION

Cocaine, similar to norepinephrine, significantly increases the total protein content and the expression of beta-MHC in cardiac ventricular myocytes. In this manner, cocaine may cause cardiac ventricular hypertrophy. This process is not inhibited by alpha- or beta-adrenergic receptor blockade.

Pigmented squamous cell carcinoma of the skin: morphologic and immunohistochemical study of five cases

Invasive pigmented squamous cell carcinoma (PSCC) of the skin is reportedly rare. Herein, we evaluate an additional five cases and compare their relative frequency with non-pigmented squamous cell carcinoma (SCC). Of 46,791 archived cases of SCC, a total of five cases of PSCC were discovered for a relative frequency of approximately 0.01%. Grossly, each tumor presented as a rapidly growing crusted papule on actinic damaged skin of the face. Microscopically, all were composed of a mixture of keratininized squamous cells and melanin-producing dendritic melanocytes. The squamous cells stained for epithelial membrane antigen, and both low and high molecular keratins. The melanocytes stained for S-100 and HMB-45. A matched series of 31 SCCs were subjected to an identical immunohistochemical battery of stains to determine if a histologically subtle and unsuspected number of intratumoral melanocytes existed in SCC. Each of the cases failed to show intratumoral melanocytes. The differential diagnosis and possible histogenesis of PSCC is discussed and the importance of extensive pathologic examination to prevent misdiagnosis is emphasized. Despite the histologic dissimilarity, the long-term prognosis of the reported cases was similar to conventional SCC.

Elastofibroma of the foot: uncommon presentation: a case report and review of the literature

We report the clinical, microscopic and ultrastructural features of an elastofibroma arising in the foot. The lesion typically occurs in the elderly, and in 85% of cases arises from the connective tissue of the posterior chest wall. The histopathologic features of this lesion are distinctive, and are characterized by a haphazard array of eosinophilic collagen and elastic fibers, associated with fibroblasts and aggregates of mature fat cells. There are only two reported cases in the literature arising in the foot.

Solitary fibrous tumor of the skin

Solitary fibrous tumor (SFT) is an uncommon mesenchymal tumor that typically arises in the pleural cavity. Comprised of spindled cells characteristically arranged in diverse architectural patterns, SFT histologically simulates a variety of benign and malignant mesenchymal tumors. The diagnosis of SFT has been refined by the availability of newer immunohistochemical markers such as CD-34 and factor XIIIa, facilitating the identification of SFTs arising in multiple extrapleural sites, including the skin. We describe three cases of primary cutaneous SFT, review the literature, and discuss the histologic and immunohistochemical differential of other cutaneous tumors that SFT can mimic.

Expression of p-27 (kip1) in nevi and melanomas

Histopathologic criteria are usually sufficient for the accurate distinction of benign from malignant melanocytic lesions of the skin. A minority of cases, however, particularly Spitz nevi, continue to pose a vexing diagnostic challenge. Recent research, however, suggests that p27 (kip1), a cell cycle inhibitory protein, may prove helpful in predicting the biologic behavior of a diverse array of human neoplasms. We analyzed 63 melanocytic lesions of the skin (21 Spitz compound nevi, 21 compound nevi, 21 melanomas, and a variety of other benign and malignant cutaneous neoplasms as a control group) for expression of p27 (kip1). The distribution of immunoreactivity was analyzed by quantifying nuclear staining in each case without knowledge of the diagnosis or outcome. Clinical history and follow-up information were obtained by chart review. There was no difference in the expression of p27 between Spitz nevi (labeling index=38.4+/-4.0), compound nevi (labeling index=40.1+/-4.8), and melanoma (labeling index=42.3+/-5.1). Logistic regression failed to show any difference in p27 labeling index between the nevi and melanoma (p=0.736). These results indicate that antibodies to p27 are not useful in distinguishing between these melanocytic lesions.

Ocular adnexal oncocytoma: a case series and clinicopathologic review of the literature

The authors report the clinical, microscopic, and ultrastructural features of four oncocytic lesions involving the ocular adnexa. Three of the lesions originated in the ocular caruncle of elderly women, and a single case was encountered from the medial eyelid of an elderly man. Each lesion clinically presented as a slow-growing, painless, red mass. The histopathologic features were distinctive, with polyhedral cells containing granular eosinophilic cytoplasm found to consist of large numbers of mitochondria on ultrastructural examination. Of the 40 cases previously reported primarily in the ophthalmologic literature, the cases reported here similarly involved the eyelid and associated ocular adnexa with a predilection for elderly women. Oncocytomas probably represent an age-associated metaplastic and neoplastic transformation of the glandular epithelium comprising the ducts of salivary glands.

Technical report: Combined carotid bifurcation endarterectomy and intra-operative transluminal angioplasty of a proximal common carotid artery stenosis: an alternative to extrathoracic bypass

A method of management of a dual stenoses affecting the proximal common carotid artery and the internal carotid artery, the tandem lesion, is described in two cases. The combination of a surgical endarterectomy of the internal carotid artery narrowing and percutaneous balloon dilatation of the more proximal common carotid artery narrowing, via the arteriotomy site, with clamping of the internal carotid artery was successfully employed to avoid an extrathoracic bypass procedure.

Merkel cell carcinoma in a renal transplant patient: increased incidence?

The identification of malignancies associated with transplantation has led to enhanced vigilance and care in these patients, as well as insight into the pathogenesis of select malignancies. We report a case of Merkel cell carcinoma, an uncommon cutaneous malignancy of neuroendocrine origin, diagnosed in a 65-year-old Caucasian man 6 years after renal transplantation. While it is well known that transplant patients are at increased risk for squamous cell carcinomas of the skin, other types may also have an increased frequency. We suggest that Merkel cell carcinoma could have an increased incidence in the transplant population.

Myofibroblastoma of the breast revisited: an etiologic association with androgens?

Myofibroblastoma of the breast is an uncommon benign stromal tumor encountered predominantly among elderly men. Histologically, myofibroblastoma is a well-circumscribed tumor comprised of bipolar spindle cells arranged in short fascicles traversed by collagen bundles. Based on previous histological, immunohistochemical, and ultrastructural observations, this tumor is thought to be derived from myofibroblasts. The pathogenesis of myofibroblastoma is unknown. Given the demographics of this lesion, the established trophic effect of steroid hormones, and the potential diagnostic utility of hormone receptor analysis in differentiating spindle cell tumors, we immunohistochemically tested for estrogen and androgen receptors in a host of spindle cell lesions including myofibroblastoma of the breast. Five cases reported herein of histological confirmed myofibroblastoma obtained from male and female breasts each showed strong nuclear antibody staining for the androgen receptor, not seen in four cases of leiomyosarcoma, three cases of fibromatosis, three cases of dermatofibrosarcoma protuberans, and two cases of monophasic synovial sarcoma. We postulate that the androgen receptor or its ligands may be pathologically related to the development of myofibroblastoma of the breast and diagnostically useful in differentiating it from other spindle cell lesions.

Fibronectin and the extracellular matrix in the perforating disorders of the skin

Despite detailed microscopic descriptions and clinical observation, little is known regarding the pathogenesis of the perforating disorders of skin, which have traditionally been subdivided into numerous microscopic entities associated with various clinical settings. An increasing body of evidence now suggests that the perforating disorders of skin are akin, and may constitute an expanded single pathologic entity. Each of the classic perforating disorders of skin, including elastosis perforans serpiginosa, perforating folliculitis, reactive perforating collagenosis, Kyrle's disease, and perforating disorder of uremia, have been shown to extrude collagen, elastin, and related extracellular matrix components through the epidermis. Considering a shared pathogenic mechanism among these entities, we explored the possible role of the extracellular matrix, in particular fibronectin, in perforating disorders of skin. Using immunohistochemical and serum determinations of extracellular matrix constituents, including fibronectin, collagen type IV, laminin, and tenascin, we showed consistent serum elevation and/or deposition of fibronectin, in each case, without a commensurate increase in laminin, collagen type IV, and tenascin. We propose that elevated serum and tissue concentrations of fibronectin may be responsible for inciting, in a physiologically aberrant manner, increased epithelial migration and proliferation culminating in perforation.

Angiomatoid malignant fibrous histiocytoma revisited. An immunohistochemical and DNA ploidy analysis

A histologic, immunohistochemical, and DNA ploidy analyses were performed on two cases of angiomatoid malignant fibrous histiocytoma to ascertain the histogenesis and relationship of endothelial, histiocytic, and fibroblastic elements. Both cases were slowly growing, grossly encapsulated. Subcutaneous masses resected from pediatric patients. Microscopically, the tumors were composed of solid masses of epithelioid and spindle cells with abnormal endothelial-lined and blood-filled cystic spaces surrounded by normal vascular structures and aggregates of lymphocytes occasionally forming germinal follicles. The tumor cells stained exclusively with CD34 and vimentin antibodies. Tumor-associated vessels stained for CD31, CD34, vimentin, and Ulex europaeus. Occasional cells within germinal follicles stained for lysozyme, CD68, and HAM56. Ploidy analysis of tumor cells showed intermediate aneuploidy with a DNA index of 1.14. Blood vessels within and surrounding the tumor as well as inflammatory cells were DNA euploid. These studies suggest that the tumor--though comprised of histologically and immunohistochemically benign-appearing euploid endothelial, fibroblastic, and inflammatory elements--contains an aneuploid population of undifferentiated mesenchymal cells.

Comparison of BACTEC 12B vs solid media for the recovery of Mycobacterium avium complex from blood cultures in AIDS patients

We compared liquid (BACTEC 12B) and solid culture media for the diagnosis of Mycobacterium avian complex (MAC) bacteremia among 258 AIDS patients with a positive blood culture. Neither culture media alone had adequate sensitivity; BACTEC 12B detected growth earlier. Use of both liquid and solid media may improve the yield of mycobacterial blood culture.

Epithelial induction in dermatofibroma: a role for the epidermal growth factor (EGF) receptor

Dermatofibroma (DF) refers to a spectrum of firm, nodular, nonencapsulated lesions that occur commonly on the extremities. Histologically, DF is composed of spindle cells with variable differentiation toward histiocytic and vascular elements, often associated with epithelial hyperplasia and basilar keratinocyte pigmentation that histologically may simulate basal cell carcinoma (BCC). The characteristic epithelial changes are likely to be mesenchyma-mediated and probably represent a host reparative response otherwise known as the inductive phenomenon. Epidermal-mesenchymal cellular interactions, including induction, occur in various stages of embryonic skin development and in response to injury with tissue repair. Cellular interaction is mediated by direct apposition of cells or by soluble protein hormones produced directly by the cell (autocrine effect) or adjacent cells (paracrine effect). Among the important soluble mediators are epidermal growth factor (EGF), which is known to stimulate the proliferation and differentiation of a variety of transformed and benign tissues. We investigated the possible etiologic association between EGF receptor (EGF-R) expression and epithelial induction in a prospective series of 20 cases of DF compared to entities such as granular cell tumor, scar tissue, and nevus sebaceus similarly showing epithelial hyperplasia. Immunohistochemical staining for EGF-R showed strong dermal staining of dendritic spindle cells and overlying hyperplastic keratinocytes in each of the DF cases. Immunohistochemical staining for EGF-R was absent within all dermal loci of granular cell tumor (n = 3), nevus sebaceus (n = 6), and scar tissue (n = 12).

Absence of Epstein-Barr virus in lymphoepitheliomalike carcinoma of the skin. Polymerase chain reaction evidence and review of five cases

Lymphoepithelioma is a lymphocyte-rich, poorly differentiated, nonkeratinizing carcinoma of the nasopharynx with distinctive clinical, epidemiologic, and etiologic features. Histologically and immunophenotypically identical tumors arising outside the nasopharynx are designated lymphoepitheliomalike carcinomas (LELCs), and have been described in the gastrointestinal tract, lung, salivary glands, thymus, and increasingly in the skin. Despite similarities between LELC and nasopharyngeal lymphoepithelioma, there is growing evidence that they are etiologically distinct. Serologic studies and molecular techniques have consistently demonstrated an etiopathologic association between Epstein-Barr virus (EBV) and lymphoepithelioma and LELC of several locations, including stomach, salivary gland, lung, and thymus. Though histologically similar. lymphoepitheliomalike carcinoma of the skin (LELCS) does not contain EBV DNA by RNA in situ hybridization. Recently, techniques for polymerase chain reaction (PCR) using fixed tissue have been described that to our knowledge have not been applied to LELCS. We studied five cases of LELCS, taking advantage of the higher sensitivity of PCR to evaluate the role, if any, of EBV specifically in the pathogenesis of LELCS.

The Effect of Hemodialysis on the Expression of Platelet Glycoproteins Ib, IIb/IIIa and P-Selectin

To determine the effect of hemodialysis on expression of platelet receptors in patients with chronic renal failure.

DESIGN

Blood sampling performed in chronic HD patients prior to the dialysis session, then 15 and 180 minutes into HD. Both dialysis machine inlet and outlet samples were taken at 15 minutes. Control subjects had a single blood sample taken.

PATIENTS

Thirteen adult males on chronic hemodialysis and 20 age and sex matched healthy controls.

MEASUREMENTS

Flow-cytometric analysis of platelet GP-Ib, GP-IIb/IIIa, and P-selectin. Plasma vWF multimers were analyzed by SDS-polyacrylamide gel electrophoresis and immunoblotting.

RESULTS

Mean channel fluorescence (MCF) for GP lb was significantly (P < 0.05) decreased in pre-dialysis patients compared to controls and decreased further 3 hours into the dialysis session compared to the start of the dialysis treatment (P < 0.01). MCF for GP IIb/IIIa between predialysis patients and controls was similar, but decreased after a single dialysis session (P < 0.01). MCF for P-selectin on platelets was similar in patients and controls, but fewer platelets from the patients expressed P-selectin compared to controls (P < 0.05). Qualitative multimeric analysis of the vWF in patients, pre- and post-HD was unchanged.

CONCLUSIONS

Alterations in platelet surface expression of GPIb, GPIIb/IIIa, and P-selectin may, partially contribute to the changes in platelet function seen in patients on hemodialysis. It is unlikely that alterations in the surface expression of these receptors alone can adequately account for the complex platelet and hemostatic changes associated with uremia and the HD procedure.

A 10-year prospective audit of outcome of surgical treatment for colorectal carcinoma

The outcome of 555 patients who underwent surgery under the care of a surgeon with an interest in colorectal disease was examined prospectively over a 10-year period with no exclusions. There was a 4.7 percent incidence of clinical leaks (10 percent for anterior resection) and an overall corrected 10-year survival rate after curative surgery of 58, 59 and 48 percent for right colonic, left colonic and rectal tumours respectively. The incidence of isolated local recurrence was 8 percent after curative surgery for carcinoma of the rectum. Twenty-five percent of patients with rectal tumours required abdominoperineal excision. Patients who underwent curative abdominoperineal excision of the rectum had corrected 5- and 10-year survival rates of 48 and 36 percent, compared with 60 and 58 percent respectively for curative anterior resection. The perioperative mortality rate of those undergoing palliative surgery was 8 percent, and 75 percent died within 2 years from distant and not local disease. A policy of always attempting resection was validated by the fact that 99 percent of primary tumours were removed with a low perioperative mortality rate (4 percent overall), a high curative resection rate and a low morbidity rate.

Papillomatous melanocytic nevi: an estrogen related phenomenon

A prospective two-month epidemiologic and histologic study of all melanocytic nevi biopsied (n = 434) at the University of Oklahoma Health Center was undertaken. Melanocytic nevi with papillomatous features (PAP) (n = 50) were found to occur predominantly in females (females = 44, males = 6; p < 0.01 adjusted for sex distribution of all melanocytic nevi). Immunohistochemical analysis of melanocytic nevi revealed concordance between PAP and intracytoplasmic nevocellular staining for estrogen-inducible pS2 protein. Melanocytic nevi without papillomatous features failed to stain for pS2 protein. These results suggest a hormone responsiveness exclusive of patient sex which may influence the pathogenesis of these distinctive melanocytic nevi.

Ectopic prostatic tissue of the anal canal

A unique case is reported of ectopic prostatic tissue present within the anal submucosa from a routine ischial decubitus resection specimen. Although ectopic prostatic tissue has been reported at loci adjoining the prostate, most notably within the urethra, this case is noteworthy by merit of its disparate location.

Eruptive vellus hair cysts and neurologic abnormalities: two related conditions?

A fifteen-year-old white boy with a history of seizure disorder, borderline cognitive function, academic difficulty, and explosive temper outbursts was evaluated for asymptomatic flesh-colored papules appearing on his chest, abdomen, and axillae. Examination of a biopsy specimen showed eruptive vellus hair cysts; results of genetic, endocrinologic, and neuropsychiatric evaluation revealed abnormalities suggestive of a previously undescribed neurocutaneous syndrome.