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Dive into the research topics where Rumelia Koren is active.

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Featured researches published by Rumelia Koren.


American Journal of Clinical Pathology | 2001

Patterns of Protein Kinase C Isoenzyme Expression in Transitional Cell Carcinoma of Bladder Relation to Degree of Malignancy

Leah Langzam; Rumelia Koren; Rivka Gal; Valentina Kugel; Adrian Paz; Amicur Farkas; Sanford R. Sampson

We determined the pattern of protein kinase C (PKC) isoform expression in human cell lines by Western blotting and immunofluorescent staining techniques. In addition, we examined PKC isoform expression in tissue samples of transitional cell carcinoma (TCC) of the bladder. PKC delta, PKC beta II, and PKC eta were found primarily in the RT4 cell line (low-grade tumor), and PKC zeta was expressed most strongly in the SUP cell line (invasive tumor). In tissue samples of urinary bladder cancer, PKC isoenzymes were expressed differentially as a function of tumor stage and grade; expression of PKC beta II and PKC delta was high in normal tissue and in low-grade tumors and decreased with increasing stage and grade of TCC. The opposite pattern was seen with PKC zeta. The differences in expression of specific isoenzymes as related to levels of malignancy of the cell lines and tissue samples suggest that the PKC family has an important role in normal and neoplastic urothelium.


Acta Histochemica | 2001

Capsular collagen staining of follicular thyroid neoplasms by picrosirius red: role in differential diagnosis.

Rumelia Koren; Eitan Yaniv; Don Kristt; J. Shvero; Vladimir Veltman; Ilyia Grushko; Rafael Feinmesser; Jaqueline Sulkes; Rivka Gal

A key criterion in the diagnosis of thyroid follicular carcinoma is capsular invasion, but invasion cannot always be demonstrated histologically. Since invasion is likely to evoke reactions in the capsular collagen, we examined the effects of invasion on capsular collagen with the picrosirius orange-red (PSR) staining technique for collagen. Under polarized light, the color of PSR-stained collagen varies as a function of the structural and biochemical properties of the collagen fibers. Capsules of widely invasive carcinomas (n = 10), minimally invasive carcinomas (n = 10), and adenomas (n = 28) were stained with the PSR method. Carcinomas were assessed along the thickened capsule for sites of definite invasion, minimal invasion, and no evidence of invasion. In adenomas, sites of thickened capsules (similar to carcinomas) were compared to sites of thin capsules. All foci were evaluated for the color and color intensity of collagen fibers. We found a significantly higher frequency of yellow-green collagen fibers than of orange-red fibers at sites of invasion, whereas orange-red fibers significantly predominated at non-invaded sites. In a minority of cases both colors occurred but the non-dominant color was of lesser intensity in all but 1 case. There were no significant differences in staining between minimally and widely invasive carcinomas. Thick capsules of adenomas consistently stained with an intense orange-red color, although weakly stained yellow-green fibers were also observed in some of these cases. We conclude that PSR staining can provide diagnostically useful information in capsular samples of carcinomas, when both color and color intensity of PSR staining are evaluated at the same site. Specifically, intense yellow-green birefringence of collagen in a thickened capsule is additional evidence for capsular invasion.


Pathology & Oncology Research | 2001

Increased incidence of diabetes mellitus in the patients with transitional cell carcinoma of urinary bladder

Sergey Kravchick; Rivka Gal; Shmuel Cytron; Ronit Peled; Yona Weissman; Eliahu Mukamel; Rumelia Koren

The progression of bladder cancer to invasive disease is highly dependent on its ability to penetrate basement membrane of urothelium. Studies on diabetic nephropathy have shown a reduction in proteoglycan content of the glomerular basement membrane. Based on the well-known fact that proteoglycans are one of the main components of basement membrane and extracellular matrix we assessed the relationship between diabetes mellitus, bladder cancer incidence and its behavior. These studies include 252 patients with microscopically confirmed transitional cell carcinoma of bladder, and 549 patients with other urological disorders who served as controls. The prevalence of diabetes mellitus in each group was assessed. The group of patients suffering from transitional cell carcinoma was divided according to etiological risk factors such as cigarette smoking, diabetes and patients that were non-smokers and did not suffer from diabetes mellitus. We assessed the features of bladder cancer behavior in each group. Logistic regression model estimation for statistical analysis was used, with transitional cell carcinoma as a dependent binary variable and age, sexes smoking and diabetes as independent variables. Statistical significance was considered at two levels: p <-0.001 and p <-0.05. Odds ratio (OR) adjusted to age, sex, cigarette smoking, diabetes mellitus and 95% Confidence Interval (CI) were calculated for TCC. In the TCC group 22.2% of the patients suffered from diabetes mellitus. In the control group 10.38% suffered from diabetes mellitus. Logistic regression analysis, OR and 95% CI showed a statistically significant relationship between diabetes and TCC. These data are comparable only with smoking (OR -2.3; 95% CI -1.6 –3.5 and OR-1.58; 95% CI -1.08 –2.4 correspondingly). Based on these data we suggest that diabetes mellitus may be considered an etiological risk factor for bladder cancer development.


Applied Immunohistochemistry & Molecular Morphology | 2000

Protein kinase C (PKC) isoenzymes immunohistochemistry in lymph node revealing solution-fixed, paraffin-embedded bladder tumors.

Rumelia Koren; Langzam L; Paz A; Livne Pm; Rivka Gal; Sampson

Protein kinase C (PKC) plays an important role in cellular differentiation and in the malignant process. In an earlier study, it was shown that the expression pattern of PKC isoenzymes is altered in some tumors compared to their corresponding normal tissue. In this study, we evaluated the pattern of PKC isoenzyme immunostaining in bladder transitional cell carcinoma (TCC) of different grades and stages and normal tissue. Twenty-seven TCC samples and six areas of normal bladder mucosa were stained with antibodies specific for the PKC isoenzymes: alpha, beta 1, beta 2, delta, and zeta. The sections were scored for intensity of staining, and the correlation with grade and stage of the tumors was computed. The PKC alpha and beta 2 immunostains were intense in normal urothelium and in all evaluated tumors. PKC beta 1 and delta stains were intense in normal and low-grade and -stage tumors and weak in high-grade and -stage tumors. The opposite trend was found for PKC zeta. PKC isoenzyme expression differs in invasive TCC compared to low-grade, low-stage TCC and normal urothelium. The value of these findings as a marker of tumor aggressiveness should be further assessed.


Inhalation Toxicology | 2009

Histopathological changes of the nasal mucosa induced by smoking

Tuvia Hadar; Eitan Yaniv; Ytzhak Shvili; Rumelia Koren; Jacob Shvero

Changes in the histopathology of the respiratory epithelium in response to cigarette smoking have been studied in depth in the lungs, but data on the nasal lining are lacking. The aim of the present retrospective study was to investigate the histological changes that occur in the nasal mucosa of smokers compared with non-smokers. The study group included 47 patients who underwent partial resection of the inferior turbinates. Archival nasal tissue samples were collected and examined by light microscopy: the number of goblet cells was counted, and the degree of inflammation, congestion, and edema was graded as mild, moderate, or severe. Epithelial thickness was measured as well. Findings were compared between smokers (nu2009=u200921) and non-smokers (nu2009=u200926). On statistical analysis, significant differences were found between the smokers and non-smokers in mean number of goblet cells in the nasal epithelium, 43.43u2009±u200916.80 vs. 16.23u2009±u20095.65 respectively (pu2009<u20090.0001), mean edema grade, 2.43u2009±u20090.75 vs. 1.12u2009±u20090.33 respectively (pu2009<u20090.0001), and mean epithelial thickness, 111.9u2009±u200925.8 μm vs. 60.4u2009±u200918.4 μm respectively (pu2009<u20090.0001). The corresponding mean values of congestion were 2u2009±u20090.71 and 1.27u2009±u20090.67 (p < 0.001), and of inflammation, 1.81u2009±u20090.60 and 1.81u2009±u20090.85 (NS). In conclusion, the histopathological findings in the nasal mucosa of smokers resemble reported findings in the bronchial respiratory epithelium. The main differences from non-smokers are greater goblet cell hyperplasia and thicker epithelium.


Ophthalmic Surgery and Lasers | 1996

Sodium Hyaluronate as a Tool in Strabismus Surgery in Rabbits

Valentin Fulga; Rumelia Koren; Nathan Ezov; Rivka Gal; Avraham Nimrod; Hanna Savir

BACKGROUND AND OBJECTIVEnThe authors tested whether coating tissue with sodium hyaluronate (Na-HA) reduced postoperative adhesions and accelerated the healing process in strabismus surgery.nnnMATERIALS AND METHODSnThe surgical technique was tested during recession and resection operations performed on 30 rabbits and was compared with the use of NaCl 0.9%. Clinical, biomicroscopic examinations were performed on postoperative days 1, 2, 7, and 30 and histopathologic examinations were performed on postoperative days 2, 7, and 30.nnnRESULTSnClinically, there were no statistically significant differences between the study group and the control group. Also, there were no statistically significant differences between the two groups for most of the histopathologic criteria; however, new vessel formation was smaller with Na-HA than without it. Statistical significance was defined as P < .05.nnnCONCLUSIONnThe authors found no significant positive effect of Na-HA on postoperative healing in rabbits.


Journal of Clinical Laser Medicine & Surgery | 2000

Differences in histochemical characteristics of gingival collagen after ER:YAG laser periodontal plastic surgery.

Gavriel Kesler; Rumelia Koren; Anat Kesler; Don Kristt; Rivka Gal

OBJECTIVEnThe aim of this study is to evaluate gingival collagen for the effect of treatment with the Erbium:YAG Kesler handpiece. The handpiece is designed for gingival resurfacing in cases of hypertrophic gingiva and gingival pigmentation.nnnBACKGROUND DATAnLasers represent recent technological advances that afford new options for the treatment of periodontal diseases. However, lasers used for esthetic gingival soft tissue resurfacing require careful histopathological evaluation of the effects on tissue. In particular, it is important to determine the effect of laser irradiation on connective tissue, especially the collagen fibers. To date, no stage-wise clinical or histological studies have been performed addressing this issue.nnnMETHODSnTen patients underwent irradiation with the following parameters: energy per pulse, 500 mJ; repetition rate, 10 pps; spot size, 3 mm. Gingival biopsy specimens were derived from 6 patients with hypertrophic gingiva and 4 with gingival pigmentation. The patients were examined before laser treatment and at 7 and 14 days after laser treatment. The tissues were fixed in tymph node revealing solution (LNRS), embedded in paraffin, sectioned at 5 microm, and stained with hematoxylin & eosin. The status of collagen in the treatment site was examined under polarized light after picrosirius red (PSR) staining. PSR is a collagen stain that differentiates collagen fiber density or size by means of a spectrum of color changes under polarized light. The major colors are red, orange, yellow, and green.nnnRESULTSnWe found a significant difference in the properties of collagen fibers at the first week and at 14 days post-treatment. In the normal gingiva, the predominant polarization colors were in the red-orange range, signifying tightly packed, mature collagen. During the first postoperative week, collagen fibers exhibited polarization colors in the green to green-yellow range, implying loosely packed collagen fibers. After 2 weeks, collagen fibers reacquired their preoperative PSR characteristics.nnnCONCLUSIONSnWe conclude that sequential series of changes accompany photothermal treatment of the gingiva. The occurrence of this sequence in all successful outcome cases may suggest the importance of these temporally sequenced changes in collagen during gum healing. In any event, the status of PSR staining of gum collagen provides a useful adjunct in the assessment of gingival health.


Applied Immunohistochemistry & Molecular Morphology | 2000

Black thyroid adenoma. Clinical, histochemical, and ultrastructural features.

Rumelia Koren; Joelle Bernheim; Pinchas Schachter; Ariel Schwartz; Anette Siegal; Rivka Gal

A 22-year-old woman with a hot thyroid nodule who was being treated with minocycline for severe acne vulgaris is presented. A partial thyroidectomy specimen revealed a black adenoma. Microscopically, the black pigment was found in the follicular cells and the colloid of the adenoma. The pigment was bleached with potassium permanganate and was Fontana-Masson stain positive. It was negative for iron, periodic acid-Schiff, and acid-fast Ziehl-Neelsen stains. All these feature suggest a melanin-like pigment. However, electron microscopic examination revealed a dense osmophilic material present within the lysosomes of the follicular cells. No melanosomes were present. Twenty-six previously reported cases are reviewed, and the possible mechanisms for the deposition of the pigment in the adenoma and its relation to minocycline degradation products are discussed.


The American Journal of Surgical Pathology | 1997

Lymph Node Revealing Solution: A New Method for Detection of Minute Axillary Lymph Nodes in Breast Cancer Specimens

Rumelia Koren; Shlomo Kyzer; Adrian Paz; Vladimir Veltman; Baruch Klein; Rivka Gal

The staging and prognosis of patients with breast cancer is related to the presence or absence of axillary lymph node involvement. However, in some cases no lymph nodes or too small a number of lymph nodes are revealed by the traditional method of palpating and sectioning the axillary fat. In the present study we demonstrate the usefulness of the lymph node revealing solution (LNRS) in breast cancer. Specimens from 13 patients, in whom <10 lymph nodes were identified in the axilla by the traditional method, were included in the study. After excising the lymph nodes by the traditional method, axillary tissue was immersed in LNRS for 6-12 hours. Additional lymph nodes, which stood out as white chalky nodules, were excised and processed as usual. The LNRS increased the mean number of nodes per case from 6.0+/-2.5 found by the traditional method to 12.54+/-4.61 nodes per case (p < 0.01). The size of the nodes identified by the LNRS was significantly smaller (p < 0.01) than those detected by the traditional method. The LNRS changed the lymph node stage of the disease in four of the studied cases (30%). LNRS seems to be the technique of choice for detection of axillary lymph nodes in cases where the number of detected lymph nodes by the traditional method is too small for accurate staging.


Journal of Histochemistry and Cytochemistry | 2001

Reduced Expression of Activin A in Focal Lymphoid Agglomerates Within Nasal Polyps

Tsipi Shoham; Eitan Yaniv; Rumelia Koren; Rivka Gal; Reshmi Parameswaran; Arkadi Kravitz; Henry Geron; Dana Markovitz; Marina Lantzki; Dov Zipori

It has been previously reported that activin A, a homodimer of the βA inhibin subunit, is secreted by stromal cells from mouse bone marrow and causes apoptotic death of mouse plasmacytoma tumor cells. Recent in vitro studies have also implicated this cytokine in the suppression of normal B-cell lymphopoiesis. In this study we examined the occurrence of activin A in nasal polyp tissues that present a combination of epithelium, mesenchyme, and vascular endothelium, with frequent massive hemopoietic infiltration. Anti-βA-chain antibodies strongly stained epithelial mucous glands and some endothelial cells, and diffusely stained the polyp stroma. Normal adult conchae were similarly stained, whereas activin A was not detected prenatally by immunostaining of nasal tissues. Staining specificity was substantiated by ligand competition assays. Detailed examination of the inflammatory polyp infiltrate showed that activin A staining was reduced in sites of focal infiltration of B-lymphoid cells. It is therefore implied that local accumulation of a large number of B-cells is associated with relatively low activin A expression.

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Eitan Yaniv

Weizmann Institute of Science

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Dov Zipori

Weizmann Institute of Science

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