Heat shock activation of telomeric sequences in different tissues of Chironomus thummi

The authors present ultrastructural and immunohistochemical characteristics of an intracranial suprasellar tumor displaying features of cavernous angioma with islets of adipose tissue. Electron microscopy revealed thin-walled vessels separated by a loose collagenous stroma containing nests of mature adipocytes as well as fibroblasts, myofibroblasts, mast cells, and a few macrophages. Intracytoplasmic lipid droplets were also identified in scattered pericytes and smooth muscle cells of vascular walls and in the transitional cells resembling smooth muscle cells and adipocytes. Many adipose tissue cells were positive for S-100 protein with polyclonal antibodies. Other lipidized tumor cells were immunoreactive for some or all of the following: smooth muscle-specific actin, factor XIIIa, vimentin, and, occasionally, for desmin. Ultrastructure and immunohistochemistry indicate that in addition to typical adipocytes, lipidized cells of another nature contribute to the characteristic appearance of the adipose tissue component of angiolipoma.     

Clear-cell smooth muscle tumor of the skin

We report a case of a previously undescribed benign neoplasm characterized by a poorly circumscribed proliferation of clear cells, arranged both singly and in elongated fascicles oriented in haphazard fashion within the middle and lower reticular dermis. The fascicles consisted of spindle-shaped cells that were periodic acid-Schiff positive and diastase labile. These cells were characterized by oval, hyperchromatic, cigar-shaped nuclei and clear cytoplasm. Immunohistochemically, neoplastic cells were diffusely positive for smooth muscle actin (1A4), common muscle actin (HHF-35), and vimentin. Immunoreactivity for fibronectin was also focally noted. The neoplasm, which we designated clear-cell smooth muscle tumor of the skin, should be distinguished from smooth muscle hamartoma and other smooth muscle proliferations at cutaneous level. We highlight in this case report the histopathologic differential diagnosis among other tumors with myofibroblastic, melanocytic, and neural differentiation.     

Intraoperative arterial occlusion in total joint arthroplasty

This report illustrates a calcified leiomyoma of deep soft tissue in the left leg of a 6-year-old boy. The tumour was composed of spindle cells arranged in interlacing bundles, between which were multiple small and large areas of calcification. Tumour cells were positive for vimentin, desmin and smooth muscle actin. Ultrastructurally, the cells showed numerous pinocytotic vesicles and bundles of intracytoplasmic filaments with smooth muscle dense bodies. Only four calcified leiomyomas have been previously reported in the deep soft tissues of limbs. Here we report a new case and suggest a new pathogenetic scheme involving alkaline phosphatase in the origin of these calcifications.     

Morphologic study of the musculature of the third eyelid in the cat (Felis catus)

The presence of smooth and striated muscles associated with protrusion or retraction of the feline third eyelid was investigated histologically in eight cats. Nine smooth muscle strands extending into the third eyelid are described and illustrated. No striated muscle fibers extending into or within the third eyelid were observed.     

Uterine bizarre lipoleiomyoma

A case of uterine bizarre lipoleiomyoma occurring in a 58-year-old woman is described. A subserosal 8.5 cm mass in the posterior wall of the body had a lipoma-like appearance with strands of fibrous tissue. Histologically, the tumor predominantly consisted of adipocytes which varied in size and shape. Some cells had the appearance of signet ring cells, some had hyperchromatic nuclei, and multivacuolated lipoblasts with hyperchromatic nuclei were observed throughout the lesion. The fibrous areas showed a proliferation of smooth muscle cells with and without atypical nuclei. There was no mitotic figure. Flow cytometric analysis indicated aneuploidy. The patient was well without disease 10 months after hysterectomy. Patients with this type of tumor need a close and long-term follow-up because of the paucity of clinical information.     

Phenotype and engraftment potential of cytokine-mobilized peripheral blood mononuclear cells

Atypical fibroxanthoma is a superficial variant of pleomorphic malignant fibrous histiocytoma. Histopathologically, it is characterized by a dermal nodule composed of bizarre cells arranged in a haphazard-to-fascicular pattern. These cells are spindle or rounded, pleomorphic and with numerous atypical mitotic figures. Some cells appear polygonal with ample and foamy cytoplasm. We recently encountered two elderly patients with atypical fibroxanthoma on their face. Histopathologically, one of the lesions was composed, almost entirely, of clear cells, whereas in the other one aggregations of clear cells constituted a half of the neoplasm. Atypical multinucleated cells with a Touton-like appearance were present. In addition to clear cells, areas of more conventional atypical spindle cells arranged in fascicles were seen, supporting the diagnosis of atypical fibroxanthoma. PAS staining failed to demonstrate glycogen in neoplastic cells. Immunohistochemistry revealed that neoplastic cells expressed positivity for vimentin, muscle-specific actin, and alpha smooth muscle actin, whereas cytokeratin, S-100 protein, EMA, CEA, and desmin were negative. Ultrastructural studies showed that neoplastic cells contained abundant rough endoplasmic reticulum, mitochondria, and numerous lipid vacuoles within the cytoplasm. Clear-cell atypical fibroxanthoma is a rare variant of atypical fibroxanthoma that should be differentiated from other clear-cell neoplasms of the skin.     

Prevalence of Helicobacter pylori infection in children from urban and rural West Virginia

BACKGROUND AND PURPOSE: Chlamydia pneumoniae infection has recently become noteworthy in relation to atherosclerosis. We investigated by immunohistochemistry the distribution of C pneumoniae infection in the atherosclerotic carotid artery. METHODS: Twenty carotid atherosclerotic lesions that were resected during carotid endarterectomy were investigated. Parallel sections were stained immunohistochemically with monoclonal antibodies for a C pneumoniae-specific antigen, macrophages, and smooth muscle cells. RESULTS: Immunoreactivity for the C pneumoniae-specific antigen was observed in 11 of 20 specimens (55%), and intense immunoreactivity was observed in 7 of 20 (35%). C pneumoniae infection was observed in endothelial cells, macrophages and in smooth muscle cells that had migrated into the atheromatous plaque, as well as in smooth muscle cells and small arteries in the media underlying the atheromatous plaques. C pneumoniae infection was most prominently observed in smooth muscle cells. The severity of the infection as demonstrated by immunohistochemistry was not significantly related to general risk factors for atherosclerosis. CONCLUSIONS: C pneumoniae widely infects endothelial cells, macrophages, and smooth muscle cells in the atherosclerotic carotid artery. The results of the present study can help us to understand how C pneumoniae infection contributes to the progression of carotid atherosclerosis.     

The dimensional characteristics of smooth muscle in rat blood vessels. A computer-assisted analysis

This investigation was undertaken to provide precise information about the dimensional characteristics of vascular smooth muscle cells as related to their paracellular matrix. The representative types of vessels were fixed at the mean blood pressures of adult male Wistar rats. The shapes, positions of the nucleus, linear dimensions, volumes, and orientation within the vessel wall were determined by a computer-assisted reconstruction of the cells from serial sections. Wall-to-lumen and cellular-to-paracellular ratios also were assessed. The smooth muscle cells were elongate, but whereas some are spindle shaped, most are not, and may be shaped like flattened triangles, paddles, boomerangs, or hourglasses, and in addition, any one of these shapes may be forked. The nucleus tended to be in the largest part of the cell, wherever that region occurred. Thus, the majority of the nuclei (61%) were not centrally located, but overlapped the middle and end thirds of the elongate cells. Of the three arteries investigated, the muscular type tail artery had cells with volumes two to three times larger (P less than 0.01) than cells in a musculoelastic (femoral) or elastic (mesenteric) artery, and six times larger (P less than 0.01) than those of the portal vein. Therefore, the smooth muscle cells of the vein were significantly smaller than those in any artery (P less than 0.01). The smooth muscle cells were aligned at a steeper angle in the vessel wall (15 degrees +/- 2 degrees) of the muscular artery than in those with more elastic tissue (9 degrees +/- 2 degrees), with a higher percentage of circumferential cells in the latter. The wall-to-lumen ratios decreased as the relative amount of paracellular matrix, particularly elastic tissue, increased in the three arteries. Therefore, irregularly shaped cells, with the nucleus in the thickest region, and having characteristic cell volumes depending on the type of vessel, form the vascular smooth muscle tissue. These factors are relevant if stereology, or measuring from two dimensions, is used to estimate size characteristics in cardiovascular disease such as hypertension. In addition, the optimum angle at which vascular strips are cut would vary, for example, when used in testing pharmacological agents.     

Granulation tissue polyposis associated with carcinoid tumours of the small intestine

We report two patients with ileal carcinoid tumours which were associated with polyps due to mucosal granulation tissue proliferation. In both cases the tumours had extensively infiltrated the small bowel wall and mesentery, and one had hepatic metastases. The mucosal surface of each specimen showed numerous, pale brown, sessile polyps which were restricted to the intestinal segment involved by carcinoid tumour, although not always closely related to neoplastic cells. The polyps were formed by the proliferation of capillaries, smooth muscle cells and myofibroblasts as demonstrated by immunohistochemistry and electronmicroscopy.     

Myofibroblastoma of the breast. Report of 8 cases

Eight cases of breast myofibroblastomas are reported: two in men and six in post-menopausal women. This study and a review of the 19 published cases permit to define more precisely the particular features of this rare and benign mesenchymal tumour. Good demarcation, lack of necrosis and nuclear atypia argue for the benign nature of the lesion. It is made up of spindle cells (mainles myofibroblasts) which are positive for vimentin and not for S 100 protein or epithelial markers. Alpha-smooth muscle cell actin and desmin labelling are heterogeneous. This immunohistochemical study underlines the variable results of myofibroblasts for smooth muscle markers reflecting different degrees in their differentiation, without resolving the question of their origin. A simple surgical excision is required for this benign lesion. No recurrence has never been observed.     

Dopamine D1/D2 antagonist combinations as antagonists of the discriminative stimulus effects of cocaine

Platelet-derived growth factor (PDGF) exists as a dimer composed of two homologous but distinct peptides termed PDGF-A and -B chains, and may exist as AA, AB, and BB isoforms. The PDGF-B chain has been implicated as a mediator of renal vascular rejection by virtue of up-regulated expression of its receptor, PDGF beta-receptor, in affected arteries. A role for PDGF-A chain in mediating intimal proliferation has been suggested in human atherosclerosis (Rekhter MD, Gordon D: Does platelet-derived growth factor-A chain stimulate proliferation of arterial mesenchymal cells in human atherosclerotic plaques? Circ Res 1994, 75:410), but no studies of this molecule in human renal allograft injury have been reported to date. We used two polyclonal antisera to detect expression of PDGF-A chain and one monoclonal antibody to detect PDGF-B chain by immunohistochemistry in fixed, paraffin-embedded tissue from 1) normal adult kidneys, 2) a series of renal transplant biopsies chosen to emphasize features of vascular rejection, and 3) allograft nephrectomies. Immunohistochemistry was correlated with in situ hybridization on adjacent, formalin fixed tissue sections from nephrectomies utilizing riboprobes made from PDGF-A and -B chain cDNA. PDGF-A chain is widely expressed by medial smooth muscle cells of normal and rejecting renal arterial vessels of all sizes by immunohistochemistry and in situ hybridization. PDGF-A chain is also expressed by a population of smooth muscle cells (shown by double immunolabeling with an antibody to alpha-smooth muscle actin) comprising the intima in chronic vascular rejection. In arteries demonstrating acute rejection, up-regulated expression of PDGF-A chain by endothelial cells was detected by both immunohistochemistry and in situ hybridization. In contrast, PDGF-B chain was identified principally in infiltrating monocytes within the rejecting arteries, similar to its localization in infiltrating monocytes in human atherosclerosis. Although less prominent than the case for PDGF-A chain, PDGF-B chain also was present in medial and intimal smooth muscle cells in both rejecting and nonrejecting renal arteries. PDGF-A and -B chains have now been localized at both the mRNA and protein levels to the intimal proliferative lesions of vascular rejection. These peptides, which are known stimuli for smooth muscle cell migration and proliferation in experimental vascular injury, may have similar stimulatory effects on smooth muscle cells in an autocrine and/or paracrine manner to promote further intimal expansion and lesion progression in this form of human vasculopathy.     

Radiation induced intracranial leiomyosarcoma: its histopathological features

This is a case of intracranial sarcoma which was recognized 23 years after irradiation therapy for pituitary adenoma. Four operations were performed because of recurrences with a short interval between each operation. Immunohistochemically, the tumour cells were stained for smooth muscle actin, human muscle actin and vimentin. It was verified as a leiomyosarcoma. This report is the first case of intracranial leiomyosarcoma associated with radiation therapy in pituitary adenoma.     

Systemic expression of a newly recognized protein, LECT2, in the human body

LECT2 (leukocyte cell-derived chemotaxin 2) is a new, recently isolated protein shown to be synthesized by hepatocytes. All hepatocytes show diffuse immunostaining for LECT2 within the cytoplasm. In the present study an attempt was made to investigate the expression of LECT2 in normal and diseased human organs and tissues, other than the liver, using indirect immunoperoxidase staining. LECT2 was found to be generally expressed in vascular, endothelial and smooth muscle cells, adipocytes, cerebral nerve cells, apical squamous epithelia, parathyroid cells, sweat and sebaceous glandular epithelia, Hassall bodies and some mononuclear cells in immunohematopoietic tissue, although some of these cells and tissues were occasionally unstained in diseased conditions. Alternatively, this protein was generally negative, although it was occasionally positively stained in osteoblasts, chondrocytes, cardiac and skeletal muscle cells, smooth muscle cells of the gastrointestinal tract, and the epithelial cells of some tissues. LECT2 seems to be related to the cell cycle or repair process following damage to a variety of cells.     

Spiral structures in the wall of the hepatic venous system in the dog

Unique spiral structures, located in the wall of the hepatic venous system in the dog, were examined in the central veins and the hepatic venous branches, utilizing microvascular corrosion casting and freeze-fracture technique in scanning electron microscopy and transmission electron microscopy of tissue sections. The whole hepatic venous system was divided into 4 portions: the central, sublobular, collecting and branches of the hepatic veins. The central vein was spindle-shaped with several compressions. Removing the endothelial cells of the central vein, pathways of venous sinusoids were like a labyrinth. In the sublobular veins, spiral structures distinctly appeared as the diameter increased. Beneath the endothelial cells in the constricted portions, smooth muscle bundles were found. The spiral structures gradually became irregular in the collecting veins and discontinuous to form shallow constrictions in cast thicker branches of the intrahepatic veins. A single, fine spindle of the central vein was formed by the arrangement of liver cells. The spiral structures of the sublobular vein were formed by smooth muscle bundles. Irregularity of the spiral structures in the collecting veins was caused by smooth muscle bundles anastomosing with adjacent ones. Disappearance of the spiral structure in cast thicker branches of the intrahepatic veins was due to absence of muscle bundles.     

Immunoelectron microscopic localization of plasminogen activator inhibitor type 1 (PAI-1) in smooth muscle cells from morphologically normal and atherosclerotic human arteries

Vascular wall fibrinolytic system proteins are believed to play a pivotal role in atherogenesis. Tissue-type plasminogen activator (t-PA) and urokinase plasminogen activator (u-PA) influence persistence of luminal thrombi and proteolysis of extracellular matrix, respectively. The major physiologic inhibitor of t-PA and u-PA is plasminogen activator inhibitor type 1 (PAI-1). All three of these fibrinolytic system proteins have been detected in vascular endothelial cells, smooth muscle cells, and macrophages by light microscopic immunohistochemistry. This study was undertaken to delineate, by immunoelectron microscopy, the loci of PAI-1 in smooth muscle cells from intact morphologically normal and atherosclerotic human arteries as well as in isolated and cultured smooth muscle cells from arteries. In intact vessels, PAI-1 immunoreactivity was associated with contractile filaments in cells in both normal and atherosclerotic tissues. Lipid-laden smooth muscle cells in atherosclerotic vessels were mainly of the synthetic phenotype and displayed lesser amounts of PAI-1 associated with rough endoplasmic reticulum and contractile filaments. Isolated smooth muscle cells exhibited either a contractile or synthetic phenotype. In the cells with a contractile phenotype, PAI-1 was associated with the contractile elements, whereas in the cells with a synthetic phenotype, the PAI-1 was associated predominantly with elements of the endoplasmic reticulum. Because PAI-1 is associated predominantly with contractile filaments in smooth muscle cells, the net amount of immunodetectable PAI-1 appears to be greater in contractile compared with synthetic phenotype cells.     

Osteosarcoma in an American robin (Turdus migratorius)

An osteosarcoma arising from the left hemimandible was diagnosed in an adult American robin (Turdus migratorius). Neoplastic spindle cells were observed extending away from foci of trabecular bone in dense sheets, occasionally within osteoid tissue. The variably pleomorphic spindle cells contained fibrillar, lightly basophilic cytoplasm, irregular, round to ovoid nuclei, and single or multiple small nucleoli. This is the first report of an osseous neoplasm in a wild passerine.     

Glomangiosarcoma of the hip: report of a highly aggressive tumour with widespread distant metastases

Malignant glomus tumour is an extremely rare neoplasm, and only a few cases with local invasive or aggressive features have been described to date. We present a distinctive case of a malignant glomus tumor arising on the skin of the left hip of a 47-year-old woman. The primary tumour was small, with a maximum diameter of 1 cm, but 2 years after the tumour was excised, multiple lung and skin metastases appeared. Post-mortem examination also revealed widespread metastases in almost all of the visceral organs. Histological examination showed that the primary tumour was composed of a sheet-like proliferation of epithelioid round or short spindle cells surrounding small venules. In addition, there was a proliferation of long spindle cells with eosinophilic fibrillary cytoplasm, which mimicked a leiomyosarcoma. The tumour cells were intensely immunopositive for actin and vimentin but were negative for desmin. This is an exceptional case of malignant glomangiomyoma with widespread metastases, which represents a distinct variant of de novo glomangiosarcoma.     

Congenital superficial angiomyxoma

Superficial angiomyxomas are rare, benign, dermal and subcutaneous tumours. We describe a 12-year-old girl who presented with a nodular swelling in the midline of her scalp that had been present since birth. Histological examination revealed an ill-defined myxoid lesion within the dermis, comprising spindle cells, blood vessels and occasional multi-nucleate giant cells. Immunohistochemical staining was negative for S-100, cytokeratin and smooth muscle actin, but focally positive for CD34. Our patient is unusual in that the angiomyxoma was present at birth, which has not previously been described. The importance of screening patients with cutaneous myxomas for cardiac lesions is discussed.     

Rapid increase in plasma nitrite concentration following intravenous administration of nipradilol

The microscopical and immunohistochemical features of a rare cutaneous leiomyoma in a cat are described. The principal characteristics of this tumour were multiple bundles of smooth muscle, either discrete or conjoined, with numerous collagen fibres between the muscle cells, and osteoid metaplasia. The tumour was designated a piloleiomyoma as it was considered to have arisen from the arrector pili muscles.