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N Karkavitsas

Publications and source records attributed to N Karkavitsas.

33 records · Page 2Linked to original sources
PubMed1997

Effectiveness of Tc-99m sestamibi compared to Ga-67 in patients with pulmonary sarcoidosis.

The authors evaluated the suitability of Tc-99m MIBI to be used as an alternative to Ga-67 in pulmonary sarcoidosis imaging. Studies were performed on 21 patients. Eleven patients (group I) had been on corticosteroid treatment before the study, while 10 patients (group II) had received no treatment. Activity of sarcoidosis was assessed from clinical manifestations of the disease, pulmonary function tests, bronchoalveolar lavage, high-resolution computed tomography, and serum biochemistry. Ga-67 imaging results were abnormal in 73% of patients of group I (n = 8) and 90% of patients of group II (n = 9). Tc-99m MIBI imaging results were abnormal in 0% of patients of group I (n = 0) and 40% of patients of group II (n = 4). The lymph nodes were better demonstrated with Ga-67. Abnormal results of Ga-67 imaging were 100% sensitive to clinically active sarcoidosis, but had a relatively low specificity (33%). In contrast, abnormal MIBI imaging had very low sensitivity (11%). The authors conclude that planar Tc-99m MIBI scintigraphic images are not sensitive for the diagnosis of pulmonary sarcoidosis.

Adult↗
PubMed1997

Non-small cell lung cancer functional imaging: increased hexakis-2-methoxy-isobutyl-isonitrile tumor clearance correlates with resistance to cytotoxic treatment.

Detection of P-glycoprotein and other multidrug resistance protein activity is currently under investigation to identify subgroups of cancer patients with tumors resistant to chemotherapy. Application of a test that reliably evaluates the phenomenon in vivo would not only serve as a predictor for responses to chemotherapy but would also be of use in testing the efficacy of multidrug resistance reversers in humans. Tc-99m radiolabeled hexakis-2-methoxy-isobutyl-isonitrile (Tc-sestamibi) has been recently shown to be extruded from cells through P-glycoprotein activity. In the present study, we examined the uptake and extrusion rate of the radiotracer in 25 patients with advanced non-small cell lung cancer undergoing chest radiotherapy, using a novel scintigraphic technique based on simulation-guided pinhole imaging. Five-min tumor images were taken 10, 60, and 120 min postinjection of 20 mCi of Tc-sestamibi. Six of 25 (24%) of tumors showed a 1.3-1.7 times higher extrusion rate as compared to that of normal lung tissue. Increased tumor clearance of Tc-sestamibi significantly correlated with resistance to radiotherapy (P = 0.05) as well as the existence of distant metastasis (P = 0.008). Patients with known resistance to chemotherapy had a higher extrusion rate as compared to chemotherapy-naive patients (P = 0.01). Moreover, increased Tc-sestamibi tumor capture was seen in patients with distant metastasis (P = 0.09). We concluded that functional imaging of lung cancer with Tc-sestamibi may have a role in predicting responses to cytotoxic treatment and in identifying tumors with aggressive behavior. Additional clinicopathological trials are required to investigate whether Tc-sestamibi kinetics correlates with P-glycoprotein expression, intratumoral angiogenesis, or other mechanisms.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1996

Functional imaging of tumours with 99Tcm-sestamibi pinhole scintigraphy.

This study presents the advantages of pinhole over parallel-hole scintigraphy in the assessment of 99Tcm-sestamibi-related tumour biology. Twenty-five patients with malignancies underwent 99Tcm-sestamibi scintigraphy (Cardiolite, Dupont) before radiotherapy, 10 of whom had repeat scintigrams after the delivery of 25 Gy and at the end of radiotherapy. A total of 45 scintigrams with parallel-hole and pinhole collimation were evaluated for tumour avidity and ability to provide images for differential biological analysis within the tumour (areas of different uptake) or beyond the main mass (multifocality, satellite tumoral foci). The pinhole collimator was located with precision over the tumour area using a radiotherapy simulator. In 19 of 45 (42%) parallel-hole scintigrams the tumours were non-avid, whereas in 13 of 45 (29%) the tumours could be identified but the image quality was very poor. In contrast, tumour avidity was assessed in all 25 cases (100%) using pinhole scintigraphy and all pinhole images were evaluable for assessment of 99Tcm-sestamibi biology. The tumour-to-normal tissue (T/N) count ratio for the tumoral centre ranged from 1.71 to 4.36 (median 3.07) vs 1.54 to 3.20 (median 2.18) at the periphery, as assessed by pinhole imaging. Of 10 cases followed up with repeated scintigrams during radiotherapy, 2 showed an increasing T/N ratio during radiotherapy, both of whom did not respond to treatment. In the other eight cases, the T/N ratio decreased progressively during radiation treatment and all eight cases showed a varying degree of response on computed tomography or magnetic resonance imaging carried out 2 months after radiotherapy. It is concluded that 99Tcm-sestamibi tumour avidity can be successfully assessed with pinhole scintigraphy. Pinhole scintigraphy provides tumour images suitable for the evaluation of biological features related to radiolabelled pharmaceuticals. The premature observation that tumours showing increased 99Tcm-sestamibi uptake during radiotherapy correlated with poor therapeutic outcome requires further investigation.

Adenocarcinoma↗
PubMed1996

[Myocardial perfusion scintigraphy using 99mTC-tetrofosmin: a comparison with coronary angiography].

AIM: Coronary angiography is still the most reliable method for the detection of coronary artery disease. In this study we compared to this method the accuracy of 99mTc-Tetrofosmin myocardial SPECT. METHOD: Fifty two patients (38 male and 14 female) were studied with stress-rest 99mTc-Tetrofosmin myocardial SPECT. Two independent observers evaluated the uptake of the radiotracer using a score from 0 to 4. All patients underwent coronary angiography and the results were compared to SPECT findings. We considered as hemodynamic significant any obstruction greater than 50% and as ischemic any myocardial region with radiotracer uptake less than 4 at stress. RESULTS: There was good segmental correspondence between tetrofosmin scintigram and angiography. Sensitivity 72.2-91.1%, specificity 80.0-88.2%, ppv 76.4-88.5% and npv 83.3-85.7%, depending on the obstructed vessel. CONCLUSION: 99mTc-Tetrofosmin myocardial SPECT is a reliable alternative for the detection of CAD.

Adult↗
PubMed1993

Cord blood erythropoietin in the presence and absence of labor in normal infants.

To evaluate erythropoietin (Ep) levels in normal labor and cesarean section we studied the cord serum of 111 term pregnancies, divided into three groups: (i) those born by normal vaginal delivery (n = 69); (ii) those delivered vaginally from mothers who were smokers (n = 20); and (iii) those delivered by elective cesarean section (n = 22). The three groups did not differ in maternal age, gestational age, birthweight, infant sex and Apgar scores. No correlation was found between Ep and hematocrit in all three groups of normal terms studied. Although not statistically significant the lower mean Ep value observed in cesarean section compared with the values obtained from normal deliveries could suggest that the process of labor may be a cause of these differences.

Adolescent↗
PubMed1992

Mechanisms accounting for the impaired natural-killer cell activity in refractory anaemia with excess of blasts.

Natural killer (NK) cells were analyzed in 38 untreated patients with refractory anaemia with excess of blasts (RAEB), using cytotoxicity assays and immunofluorescence with monoclonal antibodies. We found that patients with RAEB have normal numbers of peripheral blood and bone marrow NK cells. NK cells from RAEB patients express very low natural-killer cell activity (NKa) which may be increased significantly with recombinant alpha-interferon and recombinant interleukin-2, although it remains below the lower limit of the control range. The cells exhibit normal tumour cell binding capacity, but fail to release sufficient amounts of natural-killer cytotoxic factors (NKCFs) upon their interaction with NK-sensitive K562 cell targets or their stimulation with phytohaemagglutinin. Our results suggest that defective NKa in RAEB patients may be due, at least in part, to impaired release of functionally active NKCFs. This disturbance is probably the result of some intrinsic defect of RAEB NK cells in NKCF production, storage, and/or release. The possibility of an impairment in the activation signal provided by the stimulatory K562 cells cannot be excluded, although it seems unlikely. We postulate that this abnormality might represent a manifestation of dysplastic haemopoiesis. Further studies are certainly needed to investigate whether other defective mechanisms are also implicated in the determination of the low NKa in patients with RAEB.

Adult↗
PubMed1991

Enterogastric reflux after various types of antiulcer gastric surgery: quantitation by 99mTc-HIDA scintigraphy.

In 28 controls and 142 patients subjected to a variety of antiulcer procedures, the enterogastric reflux (EGR) was quantitated by 99mTc-HIDA scintigraphy and expressed as the EGR index on 229 different occasions. The EGR index was calculated according to two different formulas: one based on the maximal radioactivity over the gastric area as a percentage value of the total abdominal activity (EGR-Im) and the other based on the relative maximal radioactivity over the gastric area as a percentage value of the relative hepatobiliary activity (EGR-It). There was a significant positive correlation of values between the two methods (P less than 0.0001). In patients with an EGR-Im greater than 20% or EGR-It greater than 57% and postgastric surgery symptoms some of the symptoms were attributed to EGR, an antireflux procedure is expected to relieve those symptoms. Sixteen of these patients underwent Roux-en-Y gastrectomy and their preoperative symptoms were relieved.

Duodenal Ulcer↗
PubMed1988

[Bone and liver metastases in uterine, cervical and ovarian cancer].

Examination for liver and bone metastases was performed in 30 women suffering from carcinoma of the uterus and in 27 with cervical and 37 with ovarian carcinoma. Scintigraphy was the examination method of choice in bone metastases and computed tomography in liver metastases. Bone metastases were not seen in any patient in the stages I to IV with carcinoma of the cervix and ovarian carcinoma. Bone metastases were found in one patient in stage III and in one in stage IV with carcinoma of the uterus. Liver metastases were found in four patients in stages III and IV with carcinoma of the uterus and in five patients with ovarian carcinoma.

Bone Neoplasms↗
PubMed1985

[CT of a rare benign liver lymphangioma].

Lymphangiomas of the liver are very rare hamartomas and can occur singly or in multiple form. CT findings of this disease have not been reported so far. Based on a case where diagnosis had been confirmed by biopsy, the CT image is described and the findings discussed.

Aged↗
PubMedDate not supplied

Defective natural killer cell activity of peripheral blood lymphocytes correlates with the degree of neutropenia in patients with chronic idiopathic neutropenia of adults.

Natural killer cell activity (Nka) of peripheral blood mononuclear cells (PBMCs) against K562 cell targets was assessed in 66 patients with chronic idiopathic neutropenia of adults (CINA) using the 16-h 51Cr-release assay. It was found that CINA patients exhibited significantly lower Nkr than normal subjects, which strongly correlated with the degree of neutropenia and the numbers of circulating neutrophils. Patients' NKa was increased by recombinant human interleukin-2 (rhIL-2) or recombinant human interferon-alpha (rhIFN-alpha), but the values obtained did not reach the respective NKa values found in normals. However, percentages of cytokine-induced rises of NKa did not differ statistically between patients and normal subjects. No serum inhibitors of NKa were demonstrated in our patients. CINA patients had low numbers of circulating NK cells as defined by the expression of NK-cell-related surface markers CD16, CD56, and CD57. CD16+ and CD56+, but not CD57+, cells correlated with the values of baseline NKa. The numbers of all these cell subsets correlated with the degree of neutropenia and the numbers of circulating neutrophils. Using CD56+-enriched PBL suspensions, it was shown that patients' NK cells displayed normal tumor cell binding capacity and produced in vitro normal amounts of natural killer cytotoxic factor(s) against K562 cell targets upon activation with rhIFN-alpha. Finally, percentages of perforin-expressing and granzyme B-expressing CD16+ cells did not differ statistically between patients and normal controls. Based on all these observations, we concluded that CINA patients display low NKa probably because they have low numbers of circulating NK cells. No functional abnormalities of NK cells were demonstrated. The cause and the underlying mechanisms leading to NK-cell depletion in these patients remain to be clarified.

Adult↗
PubMedDate not supplied

Evaluation of inflammatory cytokines in malignant and benign pleural effusions.

We measured the levels of inflammatory cytokines interleukin-1alpha (IL-1alpha), interleukin-1beta (IL-1beta), interleukin-2 (IL-2), interleukin-6 (IL-6), interleukin-8 (IL-8), and tumor necrosis factor-alpha (TNF-alpha) in pleural effusions and serum in 65 consecutive patients: 32 with malignant pleural effusion (MPE) (group A), and 33 with inflammatory benign pleural effusion (BPE) (group B). Serum levels of 15 healthy individuals served as control. Concentrations of IL-1alpha were higher in serum compared to pleural fluid in both groups (47.1+/-33.9 vs. 25.9+/-1.7 fmol/ml, p<0.001, in group A; and 39.9+/-30.9 vs. 25.4+/-16.3 fmol/ml, p<0.02, in group B). Similarly, concentrations of IL-1beta and IL-2 were significantly higher in serum compared to pleural fluid in both groups. In contrast, IL-6, IL-8 and TNF-alpha were found at high concentration in MPE in comparison to serum IL-6: 171.8+/-60.4 vs. 7. 2+/-7 fmol/ml (p<0.001), IL-8: 1175.15+/-2385.6 vs. 285.2+/-187.2 pg/ml (p<0.05), TNF-alpha: 204.9+/-82.9 vs. 79.4+/-31.9 fmol/ml (p<0. 001). Similarly, pleural concentrations of IL-6, IL-8 and TNF-alpha were higher in BPE patients in comparison to serum IL-6: 124.3+/-56. 2 vs. 8.6+/-6.4 fmol/ml (p<0.001) IL-8: 2109.2+/-4121.5 vs. 291. 6+/-197.9 pg/ml (p<0.02), TNF-alpha: 183.8+/-28.2 vs. 86.2+/-23.9 fmol/ml (p<0.001). These data suggest that IL-6, IL-8 and TNF-alpha might be secreted locally at the site of active disease both in benign and malignant pleural effusions.

Adenocarcinoma↗
PubMedDate not supplied

Immunohistochemical analysis of the ras p21 oncoprotein in Hashimoto's thyroiditis.

We studied the ras oncogene expression using immunohistochemical detection of p21 oncoprotein in paraffin-embedded tissue sections or fine needle aspiration (FNA) material from 25 patients with Hashimoto's thyroiditis and 12 healthy individuals. We also investigated the presence of this protein in the lymphocytes of thyroid gland, as well as in peripheral blood lymphocytes. We found increased expression of p21 oncoprotein by thyroid epithelial cells in 22 patients (intensity of staining ++), whereas we observed negative or slightly positive in 9 and 3 out of 12 normal controls, respectively (intensity of staining, - or +/-). We also detected p21 oncoprotein in moderate amounts in patients' intrathyroid lymphocytes (intensity of staining +), but peripheral blood lymphocytes did not present any staining result. Our findings provided evidence that epithelial cells, as well as lymphocytes infiltrating the thyroid gland, are probably "activated" in Hashimoto's thyroiditis. The significance of this "activation" in thyroid tumorigenesis remains unknown.

Adult↗
PubMedDate not supplied

Use of CA-125 in the diagnosis and management of endometriosis: influence of treatment with danazol.

OBJECTIVE: To compare CA-125 levels in endometriotic women with normal controls. PATIENTS AND METHODS: The level of the oncofetal antigen CA-125 was measured in serum samples taken from 40 women, aged 21 to 33 years. Blood samples for CA-125 from 15 endometriotic women were measured before treatment, during the last 15 days of a 6-month administration of Danazol, and 3 months after treatment, and were compared to findings in 15 women without endometriosis (from whom blood samples were taken only once). RESULTS: The CA-125 levels were significantly higher in patients with endometriosis before treatment as compared with the controls (P < .01). The administration of Danazol significantly reduced the levels of CA-125 (P < .01), and 3 months after treatment the levels of CA-125 remained significantly lower (P < .05) as compared to the respective pretreatment values. CONCLUSION: The results support the view that the determination of CA-125 levels may assist in (a) evaluating women with endometriosis and (b) treatment with Danazol.

Adult↗