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C Stefanidis

Publications and source records attributed to C Stefanidis.

14 recordsLinked to original sources
PubMed2003

Vulvar intraepithelial neoplasia (VIN)--diagnostic and therapeutic challenges.

PURPOSE: Vulvar intraepithelial neoplasia (VIN) represents a current diagnostic and therapeutic challenge. The present retrospective study is an institutional experience on the diagnosis and management of VIN. METHODS: One hundred and thirteen women with VIN were reviewed and analyzed. Diagnosis was established by colposcopically directed biopsies whereas treatment was performed by either a surgical or a laser CO2 approach. RESULTS: The mean age of all VIN patients was 47.4 years. The most common symptom was pruritus (60.1%). The majority of the lesions were multifocal (N = 64, 56.6%) and located in the non-hairy part of the vulva (87.6%). VIN management consisted of laser CO2 treatment in 51 patients (45.1%), surgical treatment in 37 (32.7%) whereas 25 VIN, cases were managed by conventional medical treatment. The risk of disease relapse was not associated with VIN grade (p = 0.35) nor with the treatment modality used (p = 0.42). The risk of disease relapse was significantly higher for multifocal lesions (p < 0.001). Long-term follow-up of our patients showed that four patients (3.5%) developed an invasive vulvar carcinoma. CONCLUSION: Our study confirms other reports concerning the diagnostic and treatment difficulties of the management of VIN. Although the benefits of treatment are obvious there seems to be no guarantee that invasion will not occur.

Adolescent↗
PubMed2001

Spill behaviour using REACTPOOL. Part II. Results for accidental releases of silicon tetrachloride (SiCl(4)).

Silicon tetrachloride is a toxic, corrosive water reactive substance that is used widely in the process industries. On spillage from containment it creates liquid pools that can either boil or evaporate. The main feature of the pool behaviour is the exothermic reaction with water. There are three sources of water available for reaction: free ground water, substrate water and atmospheric moisture. Hydrogen chloride gas and ortho-silicic acid solid (or silica gel) are produced by the hydrolysis reaction. The purpose of this paper is to describe the dangers involved in cases of accidental releases of silicon tetrachloride, to report its properties, referring to toxicity data, major accidents and mitigation tests. It also describes pool behaviour using REACTPOOL [1]. Model results indicate that the pool behaviour is governed mainly by the amount of water available for reaction. Surface roughness and wind speed also have a significant effect on the results. Results are compared with those for other water reactive chemicals in Part III of this series of papers [3]. The generated cloud will initially contain silicon tetrachloride and hydrogen chloride with numerous processes taking place. Although silicon tetrachloride has been involved in many major hazard incidents, there are no experimental data relevant to the modelling requirements.

Accidents, Occupational↗
PubMed2001

REACTPOOL: a code implementing a new multi-compound pool model that accounts for chemical reactions and changing composition for spills of water reactive chemicals.

All chemicals that react violently with water or in contact with water liberate toxic gas are included in the list of substances covered by the majority of the international legislation on major hazards. This category includes a large number of chemicals that are used widely in the process industries. A survey of accidents that occurred in the last 10 years in the USA shows numerous major incidents that involved spillages of these substances. Even so, there are almost no experimental data on the behaviour of these chemicals on release. Furthermore, there are very few published studies on modelling the behaviour of such spillages, except in the case of hydrogen fluoride. In previous work we reported a new theoretical model [J. Haz. Mat. 62 (1998) 101-129, J. Haz. Mat. 62 (1998) 131-142, J. Haz. Mat. A67 (1999) 9-40], that describes accidental spills of SO(3) and oleum, which are substances with very complex behaviour that belong to this category. It describes both the pool [J. Haz. Mat. 62 (1998) 101-129, J. Haz. Mat. 62 (1998) 131-142] and the cloud behaviour [J. Haz. Mat. A67 (1999) 9-40]. In the work reported here the pool model was modified in a generic form in order to include other water reactive chemicals. REACTPOOL is a new code that can be used for both instantaneous and continuous liquid releases under a wide range of input parameters (steady or varying). It can be used for all liquids irrespective of their volatility and reactivity, and it describes pools consisting of more than one liquid that can have changing composition and properties. The purpose of this paper is to present the general procedure followed in REACTPOOL and to show how the new model has been modified and implemented for substances other than SO(3) and oleum. The modelling procedure has been implemented in a computer code written in Visual Basic, and results of the model have been generated using this code. It should be noted that this model requires validation data, but that the availability of such data awaits the performance of suitable experimental investigations.

Aerosols↗
PubMed1996

Body composition of children on CAPD.

Our objectives were to estimate the body composition of children on continuous ambulatory peritoneal dialysis (CAPD), assess the fat-free mass (FFM) by bioelectrical impedance (BIA) and skinfold anthropometry (SF), and determine the effect of various parameters of the nutritional status and adequacy of dialysis on body composition. The design was a noninterventional retrospective clinical trial. The percent of fat ranged from 10% to 25% (15 +/- 2), when it was calculated from SF, and was from 9% to 32% (18 +/- 2) when it was calculated from BIA. There was a significant correlation between the percent of fat calculated by SF and by BIA (r = 0.94, p < 0.0001 with limits of agreement 4.16 to 1.37 and -0.40 to -3.19). The water content of FFM ranged from 70%-79%(74 +/- 1). There was a weak but significant correlation (r = 0.64, p = 0.016) between protein catabolic rate (PCR) and KT/V (V = 60% of weight). This correlation became more significant (r = 0.83, p = 0.0007) when the V of KT/V was calculated from BIA. The prediction of body composition with the use of bioelectrical impedance is a simple and reliable technique. Serial measurements of BIA might be an important tool for the assessment of the nutritional intervention.

Adipose Tissue↗
PubMed1994

Increased left atrial pressure inhibits hypoxic pulmonary vasoconstriction.

An increase in left atrial pressure (Pla) has been reported to either inhibit or not affect hypoxic pulmonary vasoconstriction in intact dogs. We investigated mean pulmonary arterial pressure (Ppa)-flow (Q) relationships at low and high fixed Pla and Ppa-Pla relationships at fixed Q in piglets, which are known to present with a stronger hypoxic pulmonary pressor response than dogs. Seven piglets were anesthetized; equipped with balloon catheters in inferior vena cava and left atrium to control Q and Pla, respectively; and ventilated alternatively in hyperoxia [fractional concn of O2 in inspired air (FIO2) 0.4] and hypoxia (FIO2 0.12). In all experimental conditions, Ppa-Q plots were best described by a linear approximation with extrapolated pressure intercepts (Pi) not different from Pla. Hypoxia increased slope but not Pi of Ppa-Q plots. An increase in Pla from 8 to 17 mmHg induced a parallel shift of Ppa-Q plots to higher Ppa in hyperoxia but did not affect Ppa-Q plots in hypoxia. In hyperoxia, an increase in Pla at constant Q induced an approximately equal increase in Ppa, whereas in hypoxia there was no effect. The hypoxia-induced increase in Ppa was blunted by increased Pla at all levels of Q studied. We conclude that in anesthetized piglets at fixed Pla hypoxia increases the slope of Ppa-Q plots without affecting Pi and an increase in Pla inhibits hypoxic pulmonary vasoconstriction. The results suggest that no closing pressure higher than normal Pla contributes to hyperoxic or hypoxic Ppa in the intact porcine pulmonary circulation.

Animals↗
PubMed1994

Effects of a chronic aortopulmonary shunt on pulmonary hemodynamics in piglets.

Systemic-to-pulmonary shunting in growing pigs has been proposed as an experimental model of high-flow pulmonary hypertension associated with congenital heart defects. We investigated multipoint pulmonary arterial pressure (Ppa) vs. cardiac output (Q) plots and pulmonary vascular impedance spectra in 13 piglets aged approximately 4 mo and ventilated alternatively in hyperoxia (inspired O2 fraction 0.4) and in hypoxia (inspired O2 fraction 0.12). The measurements were done 8 wk after either an anastomosis between the thoracic aorta and the pulmonary trunk (n = 7 piglets) or a sham operation (n = 6). Cardiac output was altered by a manipulation of venous return. In the sham-operated piglets, hypoxia increased Ppa by an average of 12 mmHg over the entire range of Q studied, from 60 to 120 ml/kg, and increased both 0 Hz (Z0) and characteristic (Zc) pulmonary vascular impedance. In the shunted piglets compared with the sham-operated piglets in hyperoxia, Ppa was increased by an average of 5-6 mmHg at all levels of Q studied, from 60 to 120 ml/kg (P < 0.01), and Zc was also increased (P < 0.01), whereas Z0 was unchanged. In the shunted piglets, hypoxia increased Ppa at all levels of Q studied only to an average of 3 mmHg, and neither Z0 nor Zc was altered by hypoxia. We conclude that an aortopulmonary shunt of 2-mo duration in growing pigs increases both pulmonary vascular resistance and impedance and is associated with a blunting of pulmonary vascular reactivity to hypoxia.

Animals↗
PubMed1993

Pulmonary vascular impedance vs. resistance in hypoxic and hyperoxic dogs: effects of propofol and isoflurane.

The pulmonary vascular effects of inhaled anesthetics have been reported variably. We compared the effects of intravenous anesthesia (propofol) and inhalational anesthesia (isoflurane) on multipoint mean [pulmonary arterial pressure (Ppa)-pulmonary arterial occluded pressure (PpaO)]/cardiac output (Q) plots and on pulmonary vascular impedance (PVZ) spectra in eight dogs alternatively ventilated in hyperoxia [inspired O2 fraction (FIO2) 0.4] and in hypoxia (FIO2 0.1). Q was altered by a manipulation of venous return. During propofol, hypoxia increased (Ppa-PpaO) by an average of 2-3 mmHg over the entire range of Q studied, from 1 to 2.5 l.min-1 x m-2. This hypoxic pulmonary vasoconstriction (HPV) was associated with insignificant changes in PVZ. Decreasing Q in hypoxia and hyperoxia did not affect PVZ. Compared with propofol, isoflurane decreased (Ppa-PpaO) by an average of 2-5 mmHg at all levels of Q studied in both hypoxia and hyperoxia but did not affect HPV. During isoflurane anesthesia, 0 Hz PVZ was lower (P < 0.01) in hypoxia, but otherwise the PVZ spectrum was not different from that recorded during propofol anesthesia. We conclude that, in dogs, 1 degree general anesthesia with isoflurane alone decreases pulmonary vascular tone without inhibition of HPV and that 2 degrees pressure/Q plots in the time domain are more sensitive than those in the frequency domain to subtle hemodynamic changes induced by hypoxia or isoflurane at the periphery of the pulmonary vasculature.

Anesthesia↗
PubMed1993

Nutritional status and growth in children less than 12 kg treated with continuous ambulatory peritoneal dialysis.

Various parameters of nutritional status and growth in 13 children with weight less than 12 kg were estimated at the start of continuous ambulatory peritoneal dialysis (CAPD) and 1 year later. A significant improvement in weight, triceps skinfold, and serum albumin was noticed. Height and midarm muscle circumference did not change significantly. However, a significant improvement in height occurred in patients with initial abnormal height (<--2 SDS). There was no significant change in protein intake and urea nitrogen appearance (UNA) during the study period. A significant correlation between protein intake and UNA was noticed. All patients had normal serum insulinlike growth factor. In conclusion, there was no significant change in either height velocity or muscle mass despite the improvement in many nutritional parameters.

Anthropometry↗
PubMed1992

Stimulus-response curves for hypoxic pulmonary vasoconstriction in piglets.

OBJECTIVE: The aim was to characterise stimulus-response curves for hypoxic pulmonary vasoconstriction and to observe the effects of drugs reputed to enhance it: aspirin (a cyclo-oxygenase inhibitor), and doxapram (a peripheral chemoreceptor agonist). METHODS: Mean pulmonary artery pressure (Ppa) versus fraction of inspired O2 (FIO2) relationships were studied in 18 intact anaesthetised piglets, before and after the intravenous administration, in random order, of either physiological saline, 1 g aspirin, or 20 mg.kg-1 doxapram. Cardiac output (Q) was kept constant, to avoid passive Q dependent changes in Ppa. RESULTS: A progressive decrease in FIO2 from 100% to 12% was associated with an average increase in Ppa from 19 to 38 mm Hg (p < 0.001). When FIO2 was further decreased to 8%, Ppa decreased to 32 mm Hg (p < 0.01). This stimulus-response curve was unaffected by saline, but displaced in a non-PO2-dependent manner to higher Ppa by doxapram and by aspirin. CONCLUSIONS: The pulmonary vascular response to inspiratory hypoxia in intact anaesthetised piglets is biphasic, with a maximum at an FIO2 of 12%. Neither aspirin nor doxapram affect the shape of this stimulus-response curve, and in particular do not prevent low FIO2 associated inhibition of hypoxic pulmonary vasoconstriction.

Animals↗
PubMed1983

Renal osteodystrophy in children undergoing continuous ambulatory peritoneal dialysis.

Fifteen children undergoing continuous ambulatory peritoneal dialysis for 0.3 to 2.4 years were evaluated longitudinally for renal osteodystrophy. Immunoreactive parathyroid hormone, 25-OHD, total and ionized calcium, inorganic phosphate, and alkaline phosphatase levels were measured regularly. Skeletal radiographic studies were performed at the onset and conclusion of CAPD and at six-month intervals during therapy. All children received 1,25(OH)2D3 and aluminum hydroxide, and nine received supplemental calcium. Plasma 25-OHD concentrations were normal to elevated, and calcium increased steadily to high normal levels despite a trend to persistent hyperphosphatemia. The increased calcium levels suppressed parathyroid hormone overactivity in only one patient. At the onset of CAPD, nine patients had hyperparathyroid bone disease seen radiographically, three of whom also had rachitic lesions. At the end of CAPD, the hyperparathyroid lesions had improved in four patients, completely resolved in three, and deteriorated in two. Rachitic lesions had completely healed in two patients and improved in the third. However, among the six children without radiographically evident lesions at onset of CAPD, hyperparathyroid bone lesions developed in two and rachitic lesions in two others during CAPD. Although CAPD and appropriate therapy benefited most patients with renal osteodystrophy, the benefits were not uniform, and bone lesions deteriorated in some.

Adolescent↗
PubMedDate not supplied

Spontaneous rupture of a left iliac arterial aneurysm. A case report.

Isolated aneurysm of the iliac arteries is rare. It represents only 1.7% of the aneurysms of the aortic bifurcation involving the arteries (7, 13) and its rupture can be fatal. It is located deep in the pelvis and it is often difficult to detect clinically. The symptoms can mimic genitourinary, gastrointestinal or neurologic disorders. Prompt diagnosis by computerized tomography must be made in cases of emergency. Urgent aneurysmectomy is indicated in case of rupture. The average mortality rate is 50%.

Abdomen, Acute↗
PubMedDate not supplied

Benign thoracic schwannoma and postoperative chylothorax: case report and review of the literature.

Among all the neurogenic tumours, the benign intrathoracic schwannoma is a rare tumour. Most often it is discovered by accident in the course of a routine X-ray examination of the thorax. Symptoms appear only when size becomes important. The surgical removal of an intrathoracic schwannoma may result in the development of a chylothorax. According to the literature, its treatment remains controversial. The originality of the case we report here is on the one hand the exceptional size of the tumour and the success over the long term of conservative treatment with complete parenteral alimentation, and on the other hand, the inefficacy of the subcutaneous administration of the analogue of somatostatin in reducing a chylothorax with high outflow.

Adult↗