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K Chorneyko

Publications and source records attributed to K Chorneyko.

9 recordsLinked to original sources
PubMed2003

Merkel cell (neuroendocrine) carcinoma of the anal canal: report of a case.

Merkel cell tumors are rare neuroendocrine tumors typically found on sun-exposed areas such as extremities. We describe the case of a 42-year-old female with a Merkel cell tumor arising in the anal canal. The tumor was initially thought to represent a hemorrhoid arising during pregnancy and was excised locally after confirmation of extensive metastatic disease. The patient died 13 months after diagnosis with extensive metastatic disease involving the liver. In our search of the world literature there are several reports of neuroendocrine tumors in the rectum; however, no cases of documented Merkel cell tumors arising in the anal canal have been reported. These tumors seem to behave in a very aggressive manner when found in other atypical areas. The presentation symptoms were perianal discomfort and bleeding. Local excision may be the only surgical treatment necessary to control symptoms, given the propensity to early metastases and short life expectancy.

Adult↗
PubMed2002

Quantification of subcellular glycogen in resting human muscle: granule size, number, and location.

A few qualitative investigations suggested that location of muscle glycogen (G) granules in specific sites may be associated with distinct metabolic roles. Similarly, it has been suggested that the acid-soluble and -insoluble G fractions (macro- and proglycogen, respectively) are different metabolic pools and also could exist as separate entities. We employed a transmission electron microscopic technique to quantify subcellular G particle size, number, and location in human vastus lateralis biopsies of 11 resting men. The intra- and interobserver variability for the various measures was generally <4%. Granule size and number were quantified in subcellular compartments (subsarcolemmal, intra- and intermyofibrillar). Subcellular location was critical: G was more densely concentrated in the subsarcolemmal than in the myofibrillar space, whereas the single-particle volume was greater in the latter. Single-particle diameter ranged from 10 to 44 etam and followed a continuous, normal distribution. This implies that proglycogen is not a distinct entity, but rather that pro- and macroglycogen are divisions of smaller and larger molecules. These results demonstrate a compartmentalized pattern of subcellular G deposition in human skeletal muscle for both the size and density of granules.

Adult↗
PubMed2000

Gastrointestinal stromal tumors may originate from a subset of CD34-positive interstitial cells of Cajal.

Most gastrointestinal stromal tumors (GISTs), a subgroup of mesenchymal neoplasms of the gut wall, express both Kit (CD117) and CD34 proteins. It has been suggested that GISTs originate from or differentiate into interstitial cells of Cajal (ICC), after several reports indicated that ICC are likely the only cells in the gut which express both Kit and CD34. ICC are among the few cell types resident in the gut which express Kit, together with mast cells. However, the question whether or not ICC express CD34 is currently disputed. Using single-cell reverse transcriptase-polymerase chain reaction (RT-PCR) on cultured murine intestinal cells, single ICC were selected by morphology and tested for the expression of c-kit and CD34 mRNA. Most ICC were only c-kit-positive, however a subset (7 out of 43) were double positive for both c-kit and CD34. In the human small intestine, sequential immunohistochemical staining for Kit and CD34 proteins on the same 3-microm sections showed that some of the ICC surrounding Auerbach's plexus and ICC within the circular muscle layer of the small intestine were positive for both Kit and CD34. In addition, CD34(+)Kit(-) cells were seen adjacent to ICC. These data from two different techniques indicate that ICC can be double positive for Kit and CD34. Thus, GISTs with the Kit(+)CD34(+) phenotype may arise from a subpopulation of CD34(+) Kit(+) ICC.

Animals↗
PubMed2000

Gender differences in muscle inflammation after eccentric exercise.

Unaccustomed exercise is followed by delayed-onset muscle soreness and morphological changes in skeletal muscle. Animal studies have demonstrated that women have an attenuated response to muscle damage. We studied the effect of eccentric exercise in untrained male (n = 8) and female (n = 8) subjects using a unilateral exercise design [exercise (Ex) and control (Con) legs]. Plasma granulocyte counts [before (Pre) and 48 h after exercise (+48h)] and creatine kinase activity [Pre, 24 h after exercise (+24h), +48h, and 6 days after exercise (+6d)] were determined before (Pre) and after (+24h, +48h, +6d) exercise, with biopsies taken from the vastus lateralis of each leg at +48h for determination of muscle damage and/or inflammation. Plasma granulocyte counts increased for men and decreased for women at +48h (P < 0.05), and creatine kinase activity increased for both genders at +48h and +6d (P < 0.01). There were significantly greater areas of both focal (P < 0.001) and extensive (P < 0.01) damage in the Ex vs. Con leg for both genders, which was assessed by using toluidine blue staining. The number of leukocyte common antigen-positive cells/mm(2) tissue increased with exercise (P < 0.05), and men tended to show more in their Ex vs. Con leg compared with women (P = 0.052). Men had a greater total (Ex and Con legs) number of bcl-2-positive cells/mm(2) tissue vs. women (P < 0.05). Atrophic fibers with homogeneous bcl-2-positive staining were seen only in men (n = 3). We conclude that muscle damage is similar between genders, yet the inflammatory response is attenuated in women vs. men. Finally, exercise may stimulate the expression of proteins involved in apoptosis in skeletal muscle.

Adult↗
PubMed1999

Interstitial cells of Cajal as precursors of gastrointestinal stromal tumors.

Interstitial cells of Cajal (ICC) are implicated in the regulation of gut peristalsis and are immunostained by antibodies against Kit (CD117), a tyrosine kinase receptor. Most gastrointestinal mesenchymal tumors (GIMTs) are of uncertain histogenesis, although many are CD34-positive. CD34 was found to colocalize with vimentin (Vim) and the Kit-positive networks of cells within and around neural plexi, indicating that ICC can be Vim- and CD34-positive. ICCs appear to be the only Kit+CD34+Vim+ cell in the gut. Formalin-fixed, paraffin-embedded tissues from 43 GIMTs were immunostained for Kit, CD34, Vim, PGP 9.5 (PGP, a neural marker), muscle-specific actin (MSA), and other markers including desmin (Des). Eight tumors were myoid (MSA+Des+Vim-Kit-CD34-), and one was a schwannoma (PGP+S100+Vim+Kit-CD34-), but 34 tumors were of uncertain histogenesis (gastrointestinal stromal tumors, GIST), exhibiting neither a complete myoid nor a schwannian immunophenotype. All 34 were Vim+, and 33/34 were either Kit (n = 30) or CD34 (n = 23) immunoreactive. Of these 34 GIST, 24 were negative for all myoid and neural markers, 6 were PGP+S100-, and 4 were MSA+Des-. The Kit+CD34+Vim+ immunophenotype of GIST suggests that they originate from, or have differentiated into, ICC-like cells; the term ICC tumor (ICCT) is suggested. Kit is a more sensitive marker than CD34 for ICCT, but both are required in tumor identification. All clinically malignant GISTs were pathologically malignant (size, mitoses) but also showed loss of either CD34 or Kit. "Blind" examination of electron micrographs in 10 tumors showed them to be heterogeneous. Some had features seen in normal ICC, but cells could not be positively identified as being adult ICC. GIMT may therefore be classifiable into those with pure myoid, schwannian (or neural) differentiation, but the majority are of ICC origin or show ICC differentiation immunophenotypically (ICCT).

Biomarkers, Tumor↗
PubMedDate not supplied

The ultrastructure of liposarcomas with attention to "dedifferentiation".

Liposarcomas are among the most common soft tissue sarcomas. It is recognized that dedifferentiation can occur within a well-differentiated liposarcoma, but there is limited information concerning the ultrastructure of the dedifferentiated cells. A series of 8 cases has been studied by light and electron microscopy and compared with well-differentiated, myxoid, and pleomorphic liposarcomas. No definite evidence of lipoblastic differentiation could be found in the dedifferentiated cases. The tumor cells resembled atypical cells in the well-differentiated liposarcomas, supporting the close relationship between these two types of tumors. However, since no conclusive line of differentiation could be found in the dedifferentiated cases, this study supports the contention that these neoplasms are undifferentiated counterparts of well-differentiated liposarcomas.

Aged↗
PubMedDate not supplied

Oligodendroglioma with granular cells: a case report.

Oligodendrogliomas can display a spectrum of histologic and ultrastructural features. The authors describe a case of an oligodendroglioma composed almost exclusively of eosinophilic granular cells. By electron microscopy, the tumor cells had abundant lysosomes containing electron-dense pleomorphic material. Although eosinophilic granular cells can be seen focally in oligodendrogliomas, it is unusual for them to pre-dominate. By light microscopy alone, such an appearance raises a broad differential diagnosis that electron microscopy can help resolve. In addition, the ultrastructural similarities between this tumor and granular cell tumors in general support the idea that granular cell neoplasms are a phenotype expressed by a wide variety of cells.

Brain Neoplasms↗