Biomedical subjects

N Kavantzas

Publications and source records attributed to N Kavantzas.

54 records · Page 3Linked to original sources

PubMed1997

Findings of computerized nuclear morphometry of papillary thyroid carcinoma in correlation with the age of the patients.

The aim of this study was to evaluate the usefulness of nuclear morphometry in the pathology of papillary thyroid carcinoma by computer-aided image analysis and the statistical comparison of nuclear morphometric parameters with the age of patients. Seventy cases of papillary thyroid carcinoma diagnosed by fine needle aspiration (FNA) biopsies were classified into two groups according to the patients' age (group I: <45 years and group II: >45 years). The following six nuclear morphometric parameters were measured in a large number of randomly selected nuclei of each case: area, perimeter, major axis length, elongation, roundness, and compactness. The statistical analysis was performed by using special algorithms, and the results of the two groups were compared for each of the parameters measured using the t-test. Area, perimeter, and major axis length of papillary thyroid carcinoma nuclei demonstrate a statistically significant correlation with the age of patients, whereas elongation, roundness, and compactness did not show any correlation. Nuclear morphometry in association with the follow-up of patients could be suggested as an important prognostic index for papillary thyroid carcinoma.

Adolescent↗

PubMed1997

The application of image analysis in the measurement of the myocardial infarct area in an experimental model.

BACKGROUND: Thrombolytic therapy improves left ventricular ejection fraction and survival. Using the image analysis method, the study was undertaken to evaluate the effects of intraaortic balloon pump used in conjunction with reperfusion in reducing infarct size by measuring the infarct area. Also, the usefulness of image analysis as an objective method for the measurement of myocardial infarct area is evaluated. METHODS: 22 dogs were subjected to proximal left anterior descending coronary artery occlusion. The dogs were classified into 3 groups. In group I (n = 7), occlusion lasted for 6 hours. In group II (n = 6), 2 hours of occlusion were followed by reperfusion. In group III, (n = 9) after 2 hours of occlusion, the dogs were assisted with the intraaortic balloon pump throughout the 4 hours of reperfusion. The measurement of the infarcted area components (fragmentation, edema, hemorrhage and polymorphonuclear infiltrations) was followed by a semiautomatic method including in connection a microscope photographic camera, a scanner and a computer with the appropriate software. The results were analyzed statistically using the t-test. RESULT: In group I, the mean value of fragmentation was 28.2%, in group II, 10.1% (p < 0.01 versus group I) and in group III, 3.9% (p < 0.01 versus I and p < 0.05 versus group II). CONCLUSION: Reperfusion and intraaortic balloon pump increased the salvage of the ischemic myocardium over that achieved by reperfusion alone in a canine occlusion - reperfusion model. Image analysis could be considered as an accurate and objective method for the measurement of the myocardial infarct area in the experimental model of our study and it could be used in any other experimental study in which the accurate measurement of myocardial infarct area is needed.

Animals↗

PubMed1997

Findings of computerised nuclear morphometry of papillary thyroid carcinoma in correlation with known prognostic factors.

The aim of this study was the evaluation of the usefulness of nuclear morphometry in the pathology of papillary thyroid carcinoma by computer-aided image analysis and the statistical comparison of nuclear morphometric parameters with age of patients, tumor size and the presence or not of thyroid capsule invasion. Thirty three cases of papillary thyroid carcinoma were classified in two groups according to patients' age (group I: < 45 years and group II: > 45 years), according to tumor's size (group I: < 2.5 cm, group II: > 2.5 cm) and to the presence or not of thyroid capsule invasion (group I: invasion (+), group II: no invasion (-)). The following six nuclear morphometric parameters were measured in a large number of randomly selected nuclei of each case: area, perimeter, major axis length, minor axis length, elongation and roundness. The statistical analysis was performed using special algorithms and the results of the two groups of each prognostic factor examined, were compared for each of the measured parameter using the t-test. When the classification was associated with age it was shown that younger people (group I) have lower area, perimeter, major axis length, elongation and roundness means of papillary thyroid carcinoma nuclei than older ones (group II) whereas minor axis length did not show any difference between the two groups. When the classification was associated with tumor size it was shown that younger people (group I) have lower area, perimeter, major axis length means of papillary thyroid carcinoma nuclei than older ones (group II) whereas minor axis length, elongation and roundness did not show any difference between the two groups. Finally, when the cases were classified according to the presence or not of the capsule invasion it was shown that younger people (group I) have lower area, perimeter, major axis length means of papillary thyroid carcinoma nuclei than older ones (group II) whereas roundness did not showed any difference between the two groups. On the other hand younger people (group I) have higher elongation and roundness means than the older ones (group II). Nuclear morphometry in association with the patients' follow-up could represent an important prognostic index for papillary thyroid carcinoma.

Adult↗

PubMed1997

Non-Hodgkin lymphoma of brain occurring after cardiac transplantation.

This case report concerns a case of NHL which affected a 56 year-old patient after cardiac transplantation. The patient was hospitalized because of worsening congestive failure. Despite maximal medical treatment the patient continued to be in NYHA Class III-IV and underwent orthotopic cardiac allograft transplantation. The NHL developed in the CNS eighteen months after surgery and had a very quick lethal progression.

Brain Neoplasms↗

PubMed1996

The myocardial fibrosis in patients with dilated cardiomyopathy. The application of image analysis in the myocardial biopsies.

BACKGROUND: The aim of our study is to investigate whether myocardial fibrosis measured by image analysis may be considered as an important and accurate index of dilated cardiomyopathy and its prognosis. METHODS: The study group consisted of 24 patients with dilated cardiomyopathy, which was diagnosed by echocardiography, radionuclide ventriculography, cardiac catheterization, and left ventricular endomyocardial biopsy. The patients' overall disability was conventionally expressed with the criteria for functional capacity. Using image analysis, the percentage of fibrosis in a total of 35 myocardial biopsies was accurately measured, followed by a study comparing the percentage of myocardial fibrosis and the clinical parameters (left ventricular ejection fraction and overall functional capacity), showing the degree of each patient's heart failure. RESULTS: A correlation was found among fibrosis, left ventricular ejection fraction, and overall functional capacity. The cases with small values of fibrosis (< 10%) have big values of ejection fraction and belong to Class I of overall functional capacity. The cases with big values of fibrosis (> 10%) belong to Classes III and IV of overall functional capacity and have small values of ejection fraction. The results of the comparative study were graphically presented and considered significant. CONCLUSION: Myocardial fibrosis measured by image analysis might be considered an important prognostic index of dilated cardiomyopathy.

Adult↗

PubMed1996

The contribution of pathological examination of the placenta in the investigation of the causes of foetal mortality.

The purpose of this study was to evaluate the significance of histological examination of the placenta during routine post-mortem examination of foetal, perinatal and early neonatal deaths with particular reference to the cause of death. Three hundred (300) placentas were examinated over a period of three years (1988-1991). The clinical history, autopsy examination and placental histological examination were taken into account to determine the cause of death. Autopsy findings revealed the cause of death in only 33 cases (12.9%). In contrast, placental examination allowed us to determine the cause of death in 123 cases (48.4%) especially in abortions (54.4%). The most frequent abnormalities found were vascular insufficiency in intrauterine deaths (16.47%) and acute chorioamnionitis with foetal involvement in abortions (31.4%). Fifty six (56) cases with diagnoses of acute chorioamnionitis, chronic villitis of unknown aetiology and erythroblastosis were classified in the highrisk group for a subsequent pregnancy. Routine histological examination of the placenta following a perinatal death constitutes a necessary complement to autopsy examination, as it provides essential information for the cause of death and therefore helps in planning and more effective prenatal monitoring of a future pregnancy.

Abortion, Spontaneous↗

PubMed1996

The role of factor XIIIa in the mesenchymatogenesis of the human placenta: an immunohistochemical analysis.

Human placentas from normal pregnancies [9], interrupted pregnancies due to congenital anomalies of the fetuses [7] and legal abortions [9] were examined immunohistochemically using monoclonal antiserum for factor XIIIa. Hofbauer cells of the chorionic villi were strongly positive for factor XIIIa. Deeper staining in early pregnancy reflects the greater numbers of Hofbauer cells in this period of gestation. Our findings support the hypothesis that the presence of factor XIIIa in the Hofbauer cells promotes the maturation of the chorionic villi.

Chorionic Villi↗

PubMed1996

Computerized nuclear morphometry of renal cell carcinomas.

The aim of this study was the evaluation of the usefulness of nuclear morphometry in the pathology of renal cell carcinoma by computer-aided image analysis and the statistical comparison of nuclear morphometric parameters with the histologic grade of the tumors. 44 cases of renal cell carcinoma, classified by two independent pathologists into 4 histologic grades (I-IV), were examined. The following 5 nuclear morphometric parameters were measured in a large number of randomly selected nuclei of each case: Major axis length, area, elongation, roundness and compactness. The statistical evaluation was performed using one-way analysis of variance between the four groups of the histologic grades (I-IV). Between them, there was a statistically very significant difference of the mean value of all the evaluated parameters. The values of the estimated parameters, with the exception of roundness and compactness, showed a strong tendency to increase in proportion to histologic grade. Our results suggest that image analysis is a reproducible and objective method for the grading of renal cell carcinoma, and it can be helpful in the unbiased evaluation of such tumors.

Adult↗

PubMed1996

Estimation of the percentage of carotid atheromatous plaque components and investigation of a probable correlation with the neurologic status of the patients.

The aim of this study was to estimate the percentage of the carotid atherosclerotic plaque components using image analysis in 50 cases of carotid endarterectomies as well as the search for a probable correlation with the neurologic status of the patients. According to their preoperational neurologic status, the patients were classified as asymptomatic (Group I), symptomatic-TIA (Group II) and symptomatic-previous stroke (Group III). For the image analysis and the exact estimation of the carotid plaque components, special algorithms were developed. The following plaque components were measured: fibrous component, calcium, cellular infiltrations, cholesterol and hemorrhage. Between the groups I-III, there was not found any statistically significant difference of the mean value of all the estimated parameters. Our results indicate that the morphology of the carotid atheromatous plaque seems not to be correlated with the neurologic status of the patients.

Aged↗

PubMed1996

Cystadenolymphoma of the parotid gland an immunohistochemical study of the epithelial component of twenty cases.

Carcinoembryonic antigen, epithelial membrane antigen, Keratin, Desmin, Vimentin, CD30, lysozyme, alpha 1-antitrypsin, alpha 1-antichymotrypsin, S-100 protein, somatostatin and glucagon were looked for using immunohistochemical methods in the epithelial component of 20 parotid gland cystadenolymphomas and 20 normal parotid glands. Carcino-embryonic antigen, ephithelial membrane antigen, S-100 protein, and somatostatin were found in the epithelial cells of most of the cystadenolymphomas. In normal parotid tissue, carcinoembryonic antigen, epithelial membrane antigen, Keratin, alpha 1-antitrypsin, alpha 1-antichymotrypsin, and S-100 protein were found in all three types of ductal cells, somatostatin only in intercalated and striated ductal cells, and lysozyme only in acinar and intercalated ductal cells. Desmin and CD30 were found in the epithelial component of seven of the 20 tumors versus none of the 20 normal parotid glands. Glucagon and Vimentin were negative both in tumor epithelial cells and in normal parotid ductal cells. Our results support the theory that cystadenolymphomas arise from epithelial cells. The presence of lysozyme in the epithelial tumor cells and in the intercalated ductal cells of normal parotid tissue suggest that cystadenolymphomas may arise from the intercalated ducts. The presence of S-100 and somatostatin may indicate that the tumor derives from neuroendocrine structures, but further studies are needed to clarify this point.

Adenolymphoma↗

PubMed1995

Prognostic evaluation of oestrogen-regulated protein immunoreactivity in ductal invasive (NOS) breast cancer.

Determination of steroid receptors and several oestrogen-regulated proteins in mammary carcinomas is useful in the prediction of their evolution and of the likely success of endocrine therapy. Cathepsin D (Cat D), pS2 peptide and heat shock protein 27 (Hsp 27) were detected immunohistochemically in 63 infiltrating ductal (NOS) breast carcinomas, and our results were qualitatively correlated with several clinicopathological indicators and patients' overall survival. Cat D immunostaining of tumour cells was strongly associated with axillary nodal involvement (Pf = 0.0005) and so, it is directly connected with the metastatic capacity of malignant cells. pS2 immunoreactivity was correlated with oestrogen and progesterone receptor positivity (Pf = 0.0009 and Pf = 0.05 respectively) and, nonsignificantly, with good differentiation of the tumours (Pf = 0.06). Neoplastic cells expressing this protein are therefore characterised by a highly organised state of cellular physiology. Hsp 27 was expressed predominantly in tumours with one to four infiltrated lymph nodes (Pt = 0.05), and Hsp 27-positive patients were inclined to rather short survival, possibly due to chemotherapy resistance. In future, prognostic estimation of each one of the examined markers should be performed in specific large subgroups of patients. The findings of this study contribute to the establishment of criteria by which these subgroups should be formed.

Adult↗

PubMed1995

Subcutaneous sacrococcygeal myxopapillary ependymoma. A case report.

A case of myxopapillary ependymoma presenting as a primary tumor of the subcutaneous tissue of the sacrococcygeal area is reported. The tumor usually presents as an asymptomatic mass at the base of the spine in young individuals and may therefore be mistaken for a pilonidal cyst. The clinical and pathological features of this tumor are discussed.

Adult↗

PubMed1995

A comparative study of pulsed Nd:YAG and CO2 laser effect on aortic valves.

Laser angioplasty is a promising new technology, which sometimes offers the surgeon an alternative tool to conventional therapy. One of the main prerequisites of using powerful pulsed lasers in angioplasty is the optimum choice of the irradiation parameters (the wavelength, the pulse shape and duration, the energy parameters). Infrared lasers have numerous applications in surgery. Among them the pulsed CO2 laser emitting at 10.6 microns and the pulsed Nd:YAG laser emitting at 1.064 microns are the most widely used, since the delivery of laser energy in short pulses of high peak pulse power limits distant thermal effects. The CO2 laser wavelength is greatly absorbed by tissue water, while the Nd:YAG laser wavelength is poorly absorbed by water or other tissue chromophores, affecting deeper the tissue. The CO2 laser incises effectively the tissue, but presents inadequate coagulation, while the Nd:YAG laser seems to present better coagulation properties. In this work, a comparative study of pulsed Nd:YAG and CO2 lasers in ablating cardiovascular tissue, is presented. The irradiation regime of the two lasers is determined, for the specific tissue and/or pathology. Also the depth of thermally induced coagulation is measured. The results are presented according to the efficacy of each laser for incision and/or coagulation.

Angioplasty, Laser↗

PubMed1995

Interpretation of diagnostic implications of fluorescence parameters for atherosclerosis in fibrous, calcified and normal arteries.

Fluorescence spectroscopy presents great interest for the diagnosis of atherosclerosis. Nevertheless there are some difficulties in the interpretation of diagnostic information. This could be overcome by precise methods of extraction of the diagnostic parameters and convenient statistical analysis, which are the subject of this work. Fluorescence excitation-emission matrices from different categories of coronary arteries were developed and used to derive the optimum excitation wavelength on the one hand and to assign the spectra to specific chromophores on the other hand. Simple dimensionless functions (Fi) were formed by the ratio of the intensities at selected wavelength and the logistic model was used for statistical analysis. Decision surfaces were drawn and it was estimated that the probability of correct classification is 88%. The algorithm correctly diagnoses 97% of healthy from diseased samples and 80% of fibrous from calcified coronary arteries.

Algorithms↗

PubMed1995

Primary causes of fetal deaths in Athens a clinicopathological study.

The authors studied 239 cases of fetal death, occurring before the 24th week of gestation, during a five-year period, from 1989 to 1993. Based on clinical information and autopsy findings, their cases were classified as follows: 1) amniotic infection syndrome; 2) congenital anomalies; 3) disorders of the placenta and adnexae, and 4) others. The causes of fetal death were determined and evaluated statistically. In 83 cases (39 %), only autopsy revealed the cause of fetal death. The correlation of clinical and pathological findings showed that autopsy constitutes an important source of information for the determination of causes of fetal death, as well as for future genetic counselling. Moreover, it can broaden our knowledge about perinatal mortality, by correctly interpreting clinical and complementary investigation data.

Abortion, Spontaneous↗

PubMed1994

Perinatal death and thymus gland.

Three hundred (300) cases of perinatal death were autopsied and the thymus was removed for histologic examination. The histologic findings were classified into five groups: a) normal-mature thymus, b) involutional changes--"Starry sky" pattern, c) involutional changes--intense lymphocytic depletion, d) hypoplasia--aplasia, e) agenesis. The perinatal deaths were classified into five groups according to Wigglesworth's classification: 1) normally formed macerated stillborn neonates, 2) congenital malformations, 3) conditions associated with immaturity, 4) asphyxial conditions developing in labor, 5) other specific conditions (e.g. known-beta-hemolytic streptococcal infection or a fatal inborn error of metabolism). The main objective was to identify a possible correlation between sex, gestational age, birth weight, thymus weight, histologic features of the thymus and cause of death. In conclusion, a strong correlation was found between: a) weight of thymus and gestational age, b) weight of thymus and birth weight, c) weight of thymus and its histologic features, d) histologic features of thymus and cause of death, e) weight of thymus and cause of death, f) gestational age and cause of death. No correlation was found between: a) gestational age and histologic features of thymus, b) birth weight and histologic features of thymus, c) weight of thymus and sex, d) histologic features of thymus and sex, e) cause of death and sex.

Birth Weight↗

PubMed1989

[Primary angiosarcoma of the spleen. Apropos of a new case].

The authors report a new case of primary angiosarcoma of the spleen and, after a review of the literature, they discuss its clinical, diagnostic and therapeutic problems. Primary angiosarcoma of the spleen is a very rare tumor. The diagnosis should be suspected in the case of a patient with splenomegaly and unexplained anemia, with no evidence of lymphoma, leukemia or myelofibrosis. In 30% of cases, the tumor presents in the form of spontaneous rupture of the spleen. The prognosis is very poor, as it is a highly malignant tumor, even more so in the presence of early metastases with or without spontaneous rupture of the organ. Splenectomy prior to rupture could increase the survival. Patients with or without metastatic disease may be treated by combination chemotherapy, which still remains empirical and palliative.

Hemangiosarcoma↗

PubMedDate not supplied

DNA topoisomerase II-alpha immunoreactivity as a marker of tumor aggressiveness in invasive breast cancer.

OBJECTIVE: The nuclear enzyme DNA topoisomerase (topo) II breaks and rejoins DNA strands; its isoform topo IIalpha is associated with active cell proliferation of mammalian cells. The aim of this study was to examine the relationship between the expression of topo IIalpha and biological behavior markers in breast cancer. METHODS: Formalin-fixed, paraffin-embedded tissue from 88 samples of infiltrating breast cancer was immunohistochemically stained for topo IIalpha. For each case, a topo IIalpha index was determined by image analysis. Similar indexes were available for Ki-67 protein, a known cell proliferation marker, and p53, bcl-2 and c-erbB-2 oncoproteins. Each case had been staged and graded and the patients had been followed up for a mean period of 61.62 months. RESULTS: Elevated topo IIalpha immunopositivity (in >10% of malignant nuclei) was detected in 22 tumors, and this immunostatus was statistically associated with poor nuclear differentiation, absence of steroid hormone receptors, high Ki-67 immunoexpression, p53 protein accumulation and c-erbB-2 protein overexpression. Topo IIalpha expression was not linked with disease extent (stage or lymph node status). Neither proliferation marker (topo IIalpha or Ki-67) had any significant influence on the patients' recurrence-free survival. CONCLUSION: From the above results, we conclude that topo IIalpha overexpression appears to be linked with cellular dedifferentiation and potentially aggressive tumor phenotype in invasive breast cancer.

Adult↗