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Biomedical subjects

C Simopoulos

Publications and source records attributed to C Simopoulos.

At least 19 recordsLinked to original sources
PubMed2006

Hypoxia inducible factors 1alpha and 2alpha are associated with VEGF expression and angiogenesis in gallbladder carcinomas.

AIMS: To investigate the significance of the hypoxia inducible factors HIF-1alpha and HIF-2alpha in gallbladder adenocarcinomas and their relation to angiogenesis and to the expression of VEGF, an angiogenic factor transcriptionally regulated by HIFalphas. METHODS: HIF-1alpha and 2alpha expression was assessed immunohistochemically in 60 patients with early gallbladder adenocarcinomas, treated with surgery alone. In addition, the vascular density (VD) and the expression of the angiogenic factors VEGF and thymidine phosphorylase (TP) were examined. The results were correlated with clinico-pathological features and prognosis. RESULTS: Overexpression of HIF-1alpha and 2alpha was significantly associated with increased tumor angiogenesis and VEGF expression, while HIF-2alpha was linked with upregulation of TP. None of these factors were associated with T-stage and tumor grade. Although HIFs did not relate significantly with prognosis, patients with HIF-1/2 expression who failed to switch-on VEGF or intratumoral angiogenesis had a favorable outcome. CONCLUSION: Hypoxia inducible factors are upregulated in a large proportion of gallbladder adenocarcinomas, a feature strongly related to increased expression of VEGF and intensified angiogenesis.

Adenocarcinoma↗
PubMed2006

Comparison of angiogenic activity after urethral reconstruction using free grafts and pedicle flap: an experimental study.

PURPOSE: An experimental study was undertaken in order to estimate the angiogenic activity in different free grafts and pedicle flap in urethral reconstruction in an animal model. METHODS: Twenty-eight white New Zealand rabbits were randomly divided into five groups (O, A, B, C and D). A ventral urethral defect was created in all groups. In the group O, (n = 4), a simple closure of the defect was performed. Free penile skin graft (group A, n = 6), buccal mucosal graft (group B, n = 6), bladder mucosal graft (group C, n = 6), and pedicle penile skin graft (group D, n = 6) were used to bridge the urethral defect as an onlay patch. The animals were euthanized on the 21st postoperative day. The angiogenic activity was assessed with immunohistochemistry, using the anti-CD31 MoAb and the alkaline phosphatase antialkaline phosphatase procedure. The native vascularity of penile skin as well as buccal and bladder mucosa was assessed in rabbits from group O (n = 3). Statistical analysis was performed using one-way ANOVA. RESULTS: The angiogenesis seen with a magnification of x 200 in groups O, A, B, C, and D was 34.1 +/- 4.1 (mean +/- SD), 61.7 +/- 6.4, 94.3 +/- 6.4, 91.5 +/- 7.2, and 30.8 +/- 5.2 vessels per optical field, respectively. There were statistically significant differences (p < 0.001) between group O and groups A, B, C and between group A and groups B, C, D, but not (p > 0.5) between groups B and C and groups O and D. The native vascularity of penile skin, buccal mucosa and bladder mucosa was 23.3 +/- 3.0, 24.6 +/- 3.7 and 17.0 +/- 2.6 vessels per optical field, respectively. CONCLUSION: Buccal and bladder mucosal grafts exhibit a higher angiogenic activity than free and pedicle penile skin flap when transplanted in urethral defects. As the buccal mucosal graft showed the higher angiogenic activity and its harvesting is easier than bladder mucosa, we propose that in urethral reconstruction surgery the use of this graft might offer more reliable results.

Animals↗
PubMed2006

Loss of chromosome 1 in myxopapillary ependymoma suggests a region out of chromosome 22 as critical for tumour biology: a FISH analysis of four cases on touch imprint smears.

OBJECTIVE: Ependymomas are glial tumours. They constitute approximately 5-10% of intracranial tumours and are tumours which can recur. Predictive factors of outcome in ependymomas are not well established. Karyotypic studies are relatively scarce and loss of chromosome 22 has been described to correlate with recurrence. We are unaware of any reports involving chromosome 1 aberrations in the malignant progression of ependymomas. METHODS: Cytogenetic analysis of four myxopapillary ependymomas was performed using double target fluorescent in situ hybridization (FISH), focusing on chromosomes 1 and 22. RESULTS: One patient's tumour had recurred. FISH was performed on 500 nuclei/tumours. All four cases showed a loss of chromosome 22q while only one showed an additional loss of chromosome 1p, and this was the one that recurred. CONCLUSIONS: We support the presence of a tumour suppressor gene on 1p associated with relapse in myxopapillary ependymomas and suggest that status of chromosome 1p by FISH may indicate a high-risk group of patients harbouring this tumour. More studies of this type are needed towards this direction as our results refer to a minimal number of individuals analysed.

Adult↗
PubMed2006

Human embryonal tissues of all three germ layers can express the CD30 antigen. An immunohistochemical study of 30 fetuses coming after therapeutic abortions from week 8th to week 16th of gestation.

Originally, expression of the CD30 antigen was shown to be typical of the tumor cells of Hodgkin disease and of anaplastic large cell lymphomas. In reactive lymphoid tissue, CD30 is expressed only in a small population of activated lymphoid blasts. Since then, several reports have been published describing CD30 expression in non lymphoid tissues and neoplasms, such as embryonal carcinomas, seminomas, cultivated macrophages, histiocytic neoplastic cells, deciduals cells, and mesothelioma cells. In order to gain insight into the functions of CD30, given that it can mediate signals for cell proliferation and apoptosis, we studied the distribution of the antigen in different fetal archival paraffin-embedded tissues from week 8th to 16th of gestation. We investigated the immunohistochemical expression of CD30 in 30 paraffin-embedded tissue samples representing all three germ layers, using the monoclonal antibody Ber-H2 CD30 is expressed early in human fetal development (8th-10th week) in a wide variety of tissues, with the exception of the skin and thymus in which it is expressed later on. This is consistent with the observation that these organs are not fully differentiated before 10th and 13th week, respectively. No expression was observed in the cardiovascular and respiratory systems. The finding of CD30 expression in the terminal period of organogenesis, period, which is highly hormone related, implies that the antigen has an important role in cell development, maturation, and pathway to terminal differentiation in almost all fetal tissues and structures.

Abortion, Therapeutic↗
PubMed2005

Risk factors for conversion of laparoscopic cholecystectomy to open cholecystectomy.

BACKGROUND: Conversion to open cholecystectomy is still required in some patients. The aim of this study was to evaluate preoperative factors associated with conversion to open cholecystectomy in elective cholecystectomy and acute cholecystitis. METHODS: The records of 1,804 patients who underwent cholecystectomy from May 1992 to January 2004 were reviewed retrospectively. The demographics and preoperative data of patients who required conversion to laparotomy were compared to those with successful laparoscopic cholecystectomy. RESULTS: Conversion to open cholecystectomy was needed in 94 patients (5.2%),of which 44 (2.8%) had no inflammation and 50 (18.4%) had acute inflammation of the gallbladder. Male gender, age older than 60 years, previous upper abdominal surgery, diabetes, and severity of inflammation were all significantly correlated with an increased conversion rate to laparotomy. Also, the conversion from laparoscopic to open cholecystectomy in acute cholecystitis patients was associated with greater white blood cell count, fever, elevated total bilirubin, aspartate transaminase, and alanine transaminase levels, and the various types of inflammation. CONCLUSIONS: None of these risk factors were contraindications to laparoscopic cholecystectomy. This may help predict the difficulty of the procedure and permit the surgeon to better inform patients about the risk of conversion from laparoscopic to open cholecystectomy.

Acute Disease↗
PubMed2005

Distribution of somatostatin in pancreatic ductal adenocarcinoma remodels the normal pattern of the protein during foetal pancreatic development: an immunohistochemical analysis.

AIM: To determine the immunoreactivity of somatostatin during the development of the human fetal pancreas and pancreatic ductal adenocarcinoma, given that, somatostatin-positive cells were demonstrated either into its embryonic anlage or into pancreatic cancer. METHODS: Tissue sections from 15 pancreatic fetal specimens, and an equal number of ductal adenocarcinoma specimens were assessed. RESULTS: The density of positive cells in the primitive exocrine ductal epithelium and endocrine epithelium was significantly different from the relevant density in the neoplastic pancreatic tissue of mixed (ductal-endocrine) and pure ductal type (P1=0.021 P2=0.001, P3<0.0001, P4=0.003 respectively). The above values were estimated from the 8th to 10th week. There was no significant difference in the density of positive cells in the mantle zone of the islets from the 13th to the 24th week, and the neoplastic tissue of mixed (P5=0.16) and pure ductal type (P6=0.65). CONCLUSION: The immunostaining for somatostatin identifies a subgroup of pancreatic ductal adenocarcinomas with a neuroendocrine component, (initially considered as pure ductal tumors), and mixed ductal and neuroendocrine tumors. This pattern of expression in neoplasms recapitulates the normal pattern during the embryonal development of the organ, raising the question of therapeutic efficacy of somatostatin and analogues as monotherapy in pancreatic cancer management.

Adenocarcinoma↗
PubMed2005

A comparative study of invasive and oscillometric methods of arterial blood pressure measurement in the anesthetized rabbit.

INTRODUCTION: The aim of this project was to evaluate the reliability and accuracy of direct, using the central ear artery (CEA), and oscillometric, using limb-cuffs, methods of arterial blood pressure (AP) measurement in the anesthetized rabbit. METHODS: New Zealand rabbits were anesthetized using a xylazine-ketamine-isoflurane protocol. Using the abdominal aorta (ABA) as direct "gold standard" for AP measurements, ABA pressure readings, via femoral artery catheterization, were compared with those made simultaneously from the ascending aorta after median sternotomy. Thereafter, direct CEA as well as forelimb-(FL) and hindlimb-(HL) cuff oscillometric readings were compared with those made simultaneously from ABA. RESULTS: The blood pressure in the ABA correlated with that from ascending aorta. Furthermore, CEA correlated with the ABA readings. Nevertheless, at high pressures, their divergence from "true" pressure tended to increase. Oscillometric readings at the FL site correlated well with "true" pressure while those at the HL site did not. Their divergence tended to increase at high pressures when using the FL site, while it varied when using the HL site. The accuracy of measurements was moderate for the FL site while poor for the HL site. DISCUSSION: Our results suggest that the CEA can be readily used with high reliability and accuracy for direct AP measurements in the anesthetized rabbit. On the other hand, the FL-cuff oscillometric method should only be used for the evaluation of AP at low and normal pressure ranges.

Anesthesia, General↗
PubMed2005

Infarction of an accessory spleen presenting as acute abdomen in a neonate.

An accessory spleen is a relatively common condition, but the torsion thereof is extremely rare, with only nine pediatric cases reported in the literature. This paper describes a case of an accessory spleen that was found to be necrotic during an emergency laparotomy in a 14-day-old female infant with signs of acute abdomen. To our knowledge, this is the youngest reported patient. The etiology of the necrosis was thrombosis of its trophic vessels, secondary to its pedicle torsion. The literature is also reviewed.

Abdomen, Acute↗
PubMed2005

LYVE-1 immunohistochemical assessment of lymphangiogenesis in endometrial and lung cancer.

AIMS/METHODS: Normal and malignant pulmonary and endometrial tissues were analysed for lymphatic vessels to assess the process of lymphangiogenesis and its role at these sites, using specific immunostaining for LYVE-1 and the panendothelial marker CD31. RESULTS: Lymphatics were clearly demonstrated in some normal tissues (myometrium, bronchial submucosa, and intestinal submucosa), but not in others (endometrium and alveolar tissue). LYVE-1 positive lymphatic vessels were detected at the tumour periphery of endometrial and lung carcinomas, but not within the main tumour mass. Double staining for LYVE-1 and the MIB1 proliferation marker revealed a higher proliferation index in lymphatic endothelial cells at the invading front of endometrial carcinomas, compared with myometrial areas distal to the tumour. Lung and endometrial carcinomas did not have an intratumorous lymphatic network. CONCLUSIONS: Although lymphangiogenesis may occur at the invading tumour front, incorporated lymphatics do not survive. Therefore, the dissemination of cancer cells through the lymphatics may occur by invasion of peripheral cancer cells into the adjacent normal lymphatics, or through shunts eventually produced at the invading tumour front as a consequence of active angiogenesis and lymphangiogenesis.

Adenocarcinoma↗
PubMed2005

Laparoscopic cholecystectomy in a patient with situs inversus using ultrasonically activated coagulating scissors. Report of a case and review of the literature.

Situs inversus totalis is a rare defect with a genetic predisposition, which can present difficulties in the management of abdominal pathology, especially in laparoscopic surgery, due to the mirror-image anatomy. Herein, we report on a patient with situs inversus totalis and symptomatic cholelithiasis. The patient had a successful laparoscopic cholecystectomy, using ultrasonically activated coagulating scissors. Diagnostic pitfalls and technical details of the laparoscopic cholecystectomy are discussed and a review of the relevant literature is presented.

Cholecystectomy, Laparoscopic↗
PubMed2004

Induction of hepatic hematopoiesis with tenascin-C expression during the second trimester of development.

OBJECTIVE: To determine the role of tenascin-C in fetal hepatic hematopoietic proliferation and differentiation in different stages of development. STUDY DESIGN: We examined and compared the immunohistochemical expression of tenascin-C in the hepatic stromal portal fields in the first, second, and third trimester of gestation respectively, in relation to the appearance of CD34 progenitor hematopoietic, stromal progenitor and vascular endothelial positive cells. RESULTS: Our results demonstrated a quantitative difference in the second trimester of gestation concerning the expression of tenascin-C in the connective tissue stroma of the hepatic portal fields over the equivalent expression of the protein in the first (P<0.0001, t-test) and third trimester (P<0.0001, t-test). Similar changes in the above period were found concerning the expression of CD34 over the first (P<0.0001, t-test) and third trimesters (P<0.0001, t-test), suggesting a direct involvement of tenascin-C in the sustaining of hematopoietic activity. CONCLUSIONS: Our data provide evidence that an ECM glycoprotein component, tenascin-C, plays a relevant role in hematopoiesis through interaction between stromal cells and hematopoietic progenitor cells.

Female↗
PubMed2004

Mucocele of the appendix: a report of five cases.

Mucocele of the appendix is an uncommon disorder, characterized by a cystic dilatation of the lumen. It is often diagnosed clinically from signs and symptoms of acute appendicitis or, if it is asymptomatic, as an incidental finding during ultrasonography, computed tomography, and radiographic examinations of the gastrointestinal tract, or laparotomy. The incidence of mucocele ranges from 0.2% to 0.3% of all appendectomy specimens. We report five cases of appendiceal mucocele (all women, aged 19-90 years), who were admitted from January 1993 to January 2003 to our hospital. These cases represent 0.29% of the 1720 appendectomies performed during this period. Three of the patients were symptomatic and had appendectomies. The final diagnosis for mucocele was given at laparotomy. No colon neoplasms were identified during surgery, and subsequent colonoscopic examinations were also negative. The other two patients were asymptomatic of appendiceal tumor. Colonoscopy revealed two colonic malignant tumors in one patient and an adenocarcinoma of the sigmoid colon in the other. Mucocele of the appendix was diagnosed pre-operatively by ultrasound and computed tomography. One of the two patients underwent a right hemicolectomy and sigmoidectomy; the other one underwent an appendectomy, cecostomy and sigmoidectomy. Four of the patients recovered and are doing well today; one patient died on the twenty-fifth postoperative day. The most common symptom of mucocele is abdominal pain, although many patients may be asymptomatic. Mucocele is often associated with concomitant colon cancer, thus patients with this tumor should be systematically checked for other colonic lesions.

Adenocarcinoma↗
PubMed2004

Bilateral metastatic rhabdomyosarcoma to the breast in an adolescent female: touch imprint cytology and implication of MyoD1 nuclear antigen.

BACKGROUND: Rhabdomyosarcoma accounts for approximately 4% of all childhood malignancies. Breast metastases from rhabdomyosarcoma are uncommon with an incidence of 6%. CASE REPORT: We present a patient who developed bilateral mammary metastases from rhabdomyosarcoma arising in the right lower extremity. An 11-year-old female with a 20-month history of rhabdomyosarcoma was referred to our department because of bilateral breast enlargement. A needle core biopsy was performed and touch imprint slides were obtained. Cytology determined the masses to be metastases of rhabdomyosarcoma. MyoD1 immunostain and RT-PCR analysis confirmed the diagnosis. CONCLUSIONS: Cytomorphology with ancillary methods is essential in the diagnosis of metastatic breast deposits in order to avoid unnecessary mastectomy and to employ systemic treatment.

Biomarkers, Tumor↗
PubMed2004

Colostomy type in anorectal malformations: 10-years experience.

AIM: The aim of this study was to evaluate the influence of colostomy type on morbidity during the treatment of anorectal malformations. METHODS: Sixty-eight infants (male: female ratio 1.3:1) with anorectal malformations that required colostomy were treated in our clinics during the period 1991-2001. Of these patients, 26 had received a loop colostomy: 14 of these underwent posterior sagittal anorectoplasty (PSARP) at the age of 9-12 months (Group A), and 12 underwent PSARP at the age of 2-4 months (Group B). Forty-two infants received a separated-stomas colostomy and underwent PSARP at the age of 9-12 months (Group C). The incidence of complications among groups was compared using the 2 sided Fisher's exact test. RESULTS: Eight cases from group A were complicated with prolapse of the stomas, perianal wound infection, pull-through dehiscence, and anal fibrotic stricture. The only complication observed in groups B and C was perianal wound infection, which occurred in 1 case from each group. A statistically significant difference was observed in the incidence of complication between groups A and C (p<0.001) and between groups A and B (p=0.014). The results from groups B and C did not differ significantly (p=0.398). When the cases complicated with colostomy prolapse were removed from the statistical analysis, groups A and C still differed significantly (p=0.001) but groups A and B did not (p=0.069). CONCLUSIONS: As the incidence of complications increases with time after a loop colostomy, we encourage either an early corrective procedure or the modification into separated-stomas colostomy (SSC) before PSARP is performed for those cases that would involve definitive surgery in late infancy.

Abnormalities, Multiple↗
PubMed2003

Laparoscopic cholecystectomy in patients with previous upper or lower abdominal surgery.

BACKGROUND: Previous abdominal surgery has been reported as a relative contraindication to laparoscopic cholecystectomy. This study specifically examined the effect of previous intraabdominal surgery on the feasibility and safety of laparoscopic cholecystectomy. METHODS: Data from 1,638 consecutive patients who underwent laparoscopic cholecystectomy were reviewed and analyzed for open conversion rates, operative times, intra- and postoperative complications, and hospital stay. RESULTS: Of the 1,638 study patients 473 (28.9%) had undergone previous abdominal surgery: 58 upper and 415 lower abdominal operations. The 262 patients who had undergone only a previous appendectomy were excluded from further analysis. Adhesions were found in 70.7%, 58.8% and 2.1% of patients respectively, who had previous upper, lower or no previous abdominal surgery with adhesiolysis required, respectively, in 78%, 30% and 0% of these cases. There were no complications directly attributable to adhesiolysis. Patients with previous upper abdominal surgery had a longer operating time (66.4 +/- 34.2 min), a higher open conversion rate (19%), a higher incidence of postoperative wound infection (5.2%), and a longer postoperative stay (3.4 +/- 2.1 days) than those who had undergone previous lower abdominal surgery (50.8 +/- 24 min, 3.3%, 0.7%, and 2.6 +/- 1.4 days, respectively) and those without prior abdominal surgery (47.4 +/- 25.6 min, 5.4%, 1.2%, and 2.8 +/- 1.9 days, respectively). CONCLUSIONS: Previous abdominal operations, even in the upper abdomen, are not a contraindication to safe laparoscopic cholecystectomy. However, previous upper abdominal surgery is associated with an increased need for adhesiolysis, a higher open conversion rate, a prolonged operating time, an increased incidence of postoperative wound infection, and a longer postoperative stay.

Abdomen↗