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Biomedical subjects

J Papadimitriou

Publications and source records attributed to J Papadimitriou.

At least 37 records · Page 2Linked to original sources
PubMed1997

Anterior, posterior, or laparoscopic approach for the management of adrenal diseases?

BACKGROUND: At the advent of laparoscopic adrenalectomy it seemed timely to us to assess the advantages and the overall results of the different techniques that are currently used in an approach to adrenalectomy. PATIENTS AND METHODS: Between 1984 and 1995, 165 patients underwent adrenalectomy. Eighty-six patients (37 men and 49 women with a mean age of 46.4 years) underwent adrenalectomy via the anterior approach, 61 patients (18 men and 43 women with a mean age of 43.8 years) underwent posterior extraperitoneal adrenalectomy, and 18 patients (8 men and 10 women with a mean age of 48.7 years) underwent anterior laparoscopic adrenalectomy. For statistical analysis of the different comparisons between the groups we used the t test for independent samples, the Wilcoxon test, chi-square, and one way analysis of variance. RESULTS: There was no operative mortality. The morbidity was 13.9% in the anterior approach, 9.8% in the posterior approach, and 0% in the laparoscopic approach. The mean operating time for unilateral adrenalectomy was 155.3 min (range 75 to 315) for the anterior approach, 108.6 min (range 60 to 195) for the posterior approach and 116.1 min (range 75 to 180) for the laparoscopic approach. For bilateral adrenalectomy the mean operating time was 165 min for the anterior and 178 min for the posterior approach. The average diameter of tumors resected anteriorly was 8.07 cm (range 2.5 to 20), posteriorly was 5.25 cm (range 0.5 to 14), and laparoscopically was 4.03 cm (range 2 to 6.5). The mean length of postoperative hospitalization for patients undergoing unilateral adrenalectomy was 8 days (range 2 to 25) for the anterior approach, 4.5 days (range 1 to 11) for the posterior approach, and 2.2 days (range 1 to 5) for the laparoscopic approach. Patient controlled analgesia lasted 3.4 days for those operated anteriorly, 2.3 days for those operated posteriorly, and 1.08 days for those that underwent laparoscopic adrenalectomy. CONCLUSIONS: The laparoscopic approach to the adrenal promises the safest and least painful operation with shorter in-hospital stay and the best cosmetic and long-term results. The posterior approach is the fastest of all and a better overall operation than the anterior approach that should only be reserved for removing very large adrenal tumors and when concomitant intra-abdominal procedures, that can't be handled laparoscopically, are anticipated.

Adolescent↗
PubMed1997

Liver iron depletion and toxicity of the iron chelator deferiprone (L1, CP20) in the guinea pig.

The use of the iron chelator deferiprone (L1, CP20, 1,2-dimethyl-3-hydroxypyrid-4-one) for the treatment of diseases of iron overload and other disorders is problematic and requires further evaluation. In this study the efficacy, toxicity and mechanism of action of orally administered L1 were investigated in the guinea pig using the carbonyl iron model of iron overload. In an acute trial, depletion of liver non-heme iron in drug-treated guinea pigs (normal iron status) was maximal (approximately 50% of control) after a single oral dose of L1 of 200 mg kg-1, suggesting a limited chelatable pool in normal tissue. There was no apparent toxicity up to 600 mg kg-1. In each of two sub-acute trials, normal and iron-loaded animals were fed L1 (300 mg kg-1 day-1) or placebo for six days. Final mortalities were 12/20 (L1) and 0/20 (placebo). Symptoms included weakness, weight loss and eye discharge. Iron-loaded as well as normal guinea pigs were affected, indicating that at this drug level iron loading was not protective. In a chronic trial guinea pigs received L1 (50 mg kg-1 day-1) or placebo for six days per week over eight months. Liver non-heme iron was reduced in animals iron-loaded prior to the trial. The increase in a wave latency (electroretinogram), the foci of hepatic, myocardial and musculo-skeletal necrosis, and the decrease in white blood cells in the drug--treated/normal diet group even at the low dose of 50 mg kg-1 day-1 suggests that L1 may be unsuitable for the treatment of diseases which do not involve Fe overload. However, the low level of pathology in animals treated with iron prior to the trial suggests that even a small degree of iron overload (two-fold after eight months) is protective at this drug level. We conclude that the relationship between drug dose and iron status is critical in avoiding toxicity and must be monitored rigorously as cellular iron is depleted.

Administration, Oral↗
PubMed1997

Tropisetron versus Metoclopramide in the Control of Emesis in Far-Advanced Cancer.

The present study was conducted to assess the optimum treatment for nausea and vomiting in patients with far advanced cancer. More specifically, we studied patients with cancers that were too far advanced to benefit from chemotherapy or radiotherapy and whose nausea and vomiting were not due to drug intake, cranial, electrolytic, or metabolic causes. One hundred twenty patients who were under antiemetic medication with metoclopramide (MET) and suddenly presented with uncontrolled nausea and vomiting were randomized to three different therapeutic regimens: MET plus dexamethasone (DEX), MET plus tropisetron (TRO), and MET plus TRO plus DEX. Patient diary cards were used to assess nausea and vomiting. By the end of day 15, total control of vomiting was achieved in 24% of MET plus DEX patients, in 84% of MET plus TRO patients, and in 92% of MET plus TRO plus DEX patients. Total control of nausea was achieved in 18% of MET plus DEX patients, in 74% of MET plus TRO patients, and in 87% of MET plus TRO plus DEX patients. All antiemetic treatments were similarly well tolerated. TRO in combination with either MET or MET and DEX produced the best control of both nausea and vomiting.

Journal Article↗
PubMed1996

Predicting axillary lymph node metastases in breast carcinoma patients.

Routine axillary dissection is primarily used as a means of assessing prognosis to establish appropriate treatment plans for patients with primary breast carcinoma. However, axillary dissection offers no therapeutic benefit to node negative patients and patients may incur unnecessary morbidity, including mild to severe impairment of arm motion and lymphedema, as a result. This paper outlines a method of evaluating the probability of harbouring lymph node metastases at the time of initial surgery by assessment of tumour based parameters, in order to provide an objective basis for further selection of patients for treatment or investigation. The novel aspect of this study is the use of Maximum Entropy Estimation (MEE) to construct probabilistic models of the relationship between the risk factors and the outcome. Two hundred and seventeen patients with invasive breast carcinoma were studied. Surgical treatment included axillary clearance in all cases, so that the pathologic status of the nodes was known. Tumour size was found to be significantly correlated (P < 0.001) to the axillary lymph node status in the multivariate anlaysis with age (P = 0.089) and vascular invasion (P = 0.08) marginally correlated. Using the multivariate model constructed, 38 patients were predicted to have risk of nodal metastases lower than 20%, of these only 4 (10%) patients had lymph node metastases. A comparison with the Multivariate Logistic Regression (MLR) was carried out. It was found that the predictive quality of the MEE model was better than that of the MLR model. In view of the small sample size, further verification of this model is required in assessing its practical application to a larger population.

Axilla↗
PubMed1996

Pelvic floor reconstruction after major cancer surgery.

BACKGROUND: Many surgical techniques to keep the small intestine out of the pelvis after cancer surgery have been developed. METHODS: We used part of the ileum and its mesentery sutured around the linea terminalis in ten patients who underwent surgery for rectal or gynecologic carcinomas. RESULTS: All imaging studies of our patients on the tenth postoperative day confirmed the position of the bowel above the pelvis. Four of ten patients had radiation treatment postoperatively without any problems. CONCLUSION: Use of the ileum to reconstruct the pelvic floor seems to be a simple and efficacious technique to keep the pelvic area free. We believe this warrants further investigation in a larger number of patients.

Aged↗
PubMed1996

Disclosure of diagnostic information to cancer patients in Greece.

Truth-telling to cancer patients is controversial. The aim of the present study was to investigate oncologists', radiotherapists', and palliative care specialists' attitudes and truth-telling practices in Greece. A postal survey of a representative sample of 300 oncologists, radiotherapists, and palliative care specialists was made in February 1993. A total of 228 doctors completed and returned the questionnaires. It appears that withholding the truth from cancer patients remains very common in Greece.

Adult↗
PubMed1996

Initiation of impaired outer segment degradation in vivo using an antisense oligonucleotide.

This paper describes the first successful in vivo application of antisense DNA technology to induce the accumulation of photoreceptor outer segment derived debris in the retina. An antisense oligonucleotide (CatSC), which was previously demonstrated to be an effective tool to induce debris accumulation in vitro, was injected into the vitreous of pigmented and non-pigmented rats. The animals were euthanased 7 days after the injections. The number of inclusions significantly increased in the RPE layer of Long Evans and RCS-rdy + rats injected with 66 ug of CatSC to 96.2 +/- 13.6 (SD) (p < 0.0003) and 204.2 +/- 39.3 (SD) (p < 0.0001), respectively. The difference between the number of phagosome-like inclusions present in control saline, 6.6 ug of CatSC or 66 ug of sense oligonucleotide (S1) injected animals was not statistically significant. There were no abnormalities observed in the inner layers of the retina but the accumulation of phagosome-like inclusions was accompanied by disorganisation in the apices of outer segments. The large number of inclusions found in CatSC treated animals showed the characteristics of phagosomes containing stacks of undigested photoreceptor outer segment membranes which suggest that the lysosomal digestion process was halted or at least slowed down by the antisense oligonucleotide.

Animals↗
PubMed1996

Ischemia of spinal cord following elective operative procedures of the infrarenal abdominal aorta.

OBJECTIVE: Ischemia of the spinal cord following procedures of the infrarenal abdominal aorta and the iliac arteries due to aneurysmatic or occlusive disease. DESIGN: Retrospective study, duration of follow up: two years. SETTINGS: Vascular Department of the 2nd Surgical Clinic of the University of Athens, Medical School. PATIENTS: 1,112 operative procedures to the infrarenal abdominal aorta and iliac arteries, carried out from January 1, 1976 to June 30, 1994; 665 cases were aneurysms, electively operated, to which a tube graft was placed in 390 and a bifurcated graft in the remaining 265. Similarly 457 bifurcated prostheses were placed due to stenotic disease. INTERVENTIONS: Aneurysmectomy, graft insertion. MEASURES: Death, severe disability. RESULTS: Ischemic damage to the spinal cord was noted in two cases postoperatively. The first case following placement of bifurcated prosthesis due to high occlusion of the abdominal aorta and the second case following resection of an aneurysm and placement of a tube graft. One of the patients passed away on the 43rd postoperative day, and the other 18 months after was able to stand but, however, could not walk easily without the help of another person. CONCLUSIONS: The complication seems to be multicausal, carrying a bad prognosis and cannot be foreseen. The stable hemodynamic condition of the patient during the operative and postoperative period with revascularisation of at least one hypogastric artery, reduces the time of aortic occlusion and securing collateral circulation might reduce these complications. Also preopeorative angiography of the spinal cord with more sophisticated techniques, might constitute the most reliable prognosis in the future.

Aged↗
PubMed1996

Our first experience applying simultaneous bilateral carotid endarterectomy.

Simultaneous bilateral carotid endarterectomy (SBCE) has been very rarely cited in the international literature. Twelve patients underwent 24 SBCE's (Group A). They were compared with 22 bilateral staged endarterectomies in 11 (Group B) and 155 cases with unilateral endarterectomies (Group C). The indications and surgical management were similar and the accompanying risk factors were comparable in the 3 groups. Shunt or patch was not used and occlusion time was 13 +/- 2'. Total occlusion time in the SBCE was 25 +/- 3'. The results are comparable in the 3 groups. In the SBCE group one case of TIA was particularly noted together with another case with transient vocal cord paresis; however no death, myocardial infarct, respiratory problems or permanent damage of the central nerves were observed in this group. Despite the small number of our patients together with that of the international literature, it seems that a better preoperative assessment of the function of the circle of Willis in association with meticulous surgical technique and proper patient selection, encourages the tactics of simultaneous bilateral carotid endarterectomy.

Carotid Stenosis↗
PubMed1995

Interferon-alpha inhibits erythropoietin-induced proliferation, but not differentiation, and restricts erythroleukemia development.

The immature erythroid cell line J2E responds to erythropoietin (Epo) by proliferating and terminally differentiating into hemoglobin-synthesizing red blood cells. These cells produce a rapid, fatal erythroleukemia in mice characterized by hepatosplenomegaly and severe anemia. The aim of this study was to investigate the effects of murine interferons-alpha (MuIFN-alpha) on J2E cells in vitro and in vivo. Here we show that in culture MuIFN-alpha inhibited the Epo-induced proliferation of J2E cells but did not interfere with differentiation. When mice with J2E erythroleukemias were treated with MuIFNs in vivo, an extension of their life span was observed. Moreover, numerous necrotic lesions of infiltrating leukemic cells were detected in the spleens of these mice. Finally, ex vivo treatment of leukemic bone marrow cells with Epo and MuIFNs delayed mortality even further. It was concluded that MuIFNs (1) suppressed the proliferation of J2E cells in vitro but did not affect Epo-induced differentiation, and (2) inhibited the progress of erythroleukemias, especially in combination with Epo.

Animals↗
PubMed1995

A rapid fatal erythroleukemia caused by J2E cells can be treated ex vivo with erythropoietin.

The J2E cell line is an immature erythroid line which terminally differentiates in response to erythropoietin (epo), producing mature, hemoglobin-synthesizing red blood cells. We have shown that when these cells were injected into mice a rapid and fatal erythroleukemia developed with symptoms of severe anemia and hepatosplenomegaly. Southern blotting demonstrated that the leukemic cells were the introduced J2E cells. In addition to spleen and liver, the bone marrow was a major site of leukemic cell infiltration, and when grown in vitro leukemic cells from bone marrow remained responsive to erythropoietin. We reasoned, therefore, that treatment of mice with this hormone should alleviate the erythroleukemia, but regular injections of epo in vivo failed to arrest the progress of the disease. However, when bone marrow from leukemic mice was exposed continuously to the hormone ex vivo, before reinfusion into naive recipients, a marked extension in life span was observed. It was concluded that ex vivo epo treatment could be used therapeutically for J2E cell erythroleukemias.

Animals↗
PubMed1995

Emergence of myeloid cells from cultures of J2E erythroid cells is linked with karyotypic abnormalities.

J2E cells are an erythroid cell line immortalized at the proerythroblast stage of differentiation by the J2 retrovirus which contains the raf and myc oncogenes. In response to erythropoietin, these cells terminally differentiate into mature, hemoglobin-producing erythroid cells. We have shown previously that B cells overexpressing raf and myc acquired the phenotype of macrophages, and here we demonstrate that, under adverse growth conditions, myeloid cells can also emerge from J2E cultures. Morphologically, ultrastructurally, and by cytochemical analyses, these cells resembled monocytic precursor cells at different stages of differentiation. They no longer responded to erythropoietin, failed to express an erythroid-specific surface antigen, and ceased producing transcripts for globin genes, GATA-1 and SCL. Most of the converted cells displayed surface antigens typically found on myeloid cells and in vivo produced histiocytomas with severe cachexia, instead of erythroleukemias. All of the myeloid convertants had karyotypic abnormalities, and we speculate that these mutations may have triggered the transition from erythroid to myeloid phenotype. Overexpression of raf and myc oncogenes may have generated genetic instability, which then influenced the commitment of cells to specific lineages.

Animals↗
PubMed1994

Glandular peripheral nerve sheath tumours.

Glandular differentiation in peripheral nerve sheath neoplasms is a rare but well recognised phenomenon, believed to represent the least common of the various forms of heterologous differentiation which may occur in tumours of peripheral nerve. This group of tumours--the 'glandular peripheral nerve sheath neoplasms'--are the subject of this short review. The majority of glandular peripheral nerve sheath neoplasms arise in patients with von Recklinghausen's disease and follow a malignant course, but both benign and sporadic forms have now been described. Neither the presence nor the appearance of the glandular foci are believed to influence patient outcome. Predictions of likely biologic behaviour are best based upon an assessment of the nature of the accompanying spindle cell stroma. Glandular peripheral nerve sheath neoplasms must be distinguished from various tumours of soft tissue which may share similar histological features e.g. synovial sarcoma and the epitheloid nerve sheath tumours. Immunohistochemistry and ultrastructural examination may aid in this regard, and have also contributed to our understanding of the nature and origin of the glandular structures, though questions regarding their histogenic origins remain somewhat controversial.

Cell Differentiation↗