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Biomedical subjects

G Bougioukas

Publications and source records attributed to G Bougioukas.

11 recordsLinked to original sources
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

The supportive value of pre-bypass L-glutamate loading in patients undergoing coronary artery bypass grafting.

AIM: Experimental studies have demonstrated that an exogenous supply of glutamate improves mechanical function and recovery of ischemic myocardium. The aim of the present study was to investigate the effect of myocardial pre-bypass loading with glutamate on myocardial protection during global ischemia and reperfusion of patients undergoing coronary artery bypass grafting (CABG). METHODS: The study was double blinded. Twenty patients undergoing elective CABG were randomized to receive L-glutamate (n = 10) or normal saline (n = 10). Intracellular levels of glutamate, ATP and lactate were measured in left ventricular biopsies collected 10 min after aortic clamp release. Hemodynamic data, and postoperative release of CK-MB and troponin T were also measured. RESULTS: Pre-bypass administration of glutamate resulted in myocardial glutamate loading since glutamate levels were significantly higher in the glutamate group of patients than in controls (18.6 +/- 3.1 versus 8.7 +/- 1.2 microg/g tissue, P < 0.001). In the same group ATP levels were also significantly higher (2.4 +/- 0.7 versus 1.5 +/- 0.4 microg/g tissue, P < 0.05) and lactate levels significantly less than in controls (6.9 +/- 1.9 versus 12.0 +/- 2.1 microg/g tissue, P < 0.001). Glutamate patients had statistically significantly superior post-bypass hemodynamic performance (cardiac index, left ventricular stroke work index, systemic vascular resistance and pulmonary vascular resistance). Statistically significantly lower levels of CK-MB (6 h postoperative), total and peak CK-MB, troponin T (24 h postoperative), and total troponin T were found in the glutamate group. CONCLUSIONS: The results of this preliminary study indicate that pre-bypass intravenous administration of glutamate in patients undergoing CABG has a supportive effect on myocardial metabolism during global ischemia and reperfusion, improves patients' postoperative hemodynamic performance and reduces postoperative cardiac enzyme release.

Adenosine Triphosphate↗
PubMed2003

Lactate dehydrogenase-5 (LDH-5) overexpression in non-small-cell lung cancer tissues is linked to tumour hypoxia, angiogenic factor production and poor prognosis.

Lactate dehydrogenase-5 (LDH-5) catalyses the reversible transformation of pyruvate to lactate, having a principal position in the anaerobic cellular metabolism. Induction of LDH-5 occurs during hypoxia and LDH-5 transcription is directly regulated by the hypoxia-inducible factor 1 (HIF1). Serum LDH levels have been correlated with poor prognosis and resistance to chemotherapy and radiotherapy in various neoplastic diseases. The expression, however, of LDH in tumours has never been investigated in the past. In the present study, we established an immunohistochemical method to evaluate the LDH-5 overexpression in tumours, using two novel antibodies raised against the rat muscle LDH-5 and the human LDH-5 (Abcam, UK). The subcellular patterns of expression in cancer cells were mixed nuclear and cytoplasmic. In direct contrast to cancer cells, stromal fibroblasts were reactive for LDH-5 only in a minority of cases. Serum LDH, although positively correlated with, does not reliably reflect the intratumoral LDH-5 status. Lactate dehydrogenase-5 overexpression was directly related to HIF1alpha and 2alpha, but not with the carbonic anhydrase 9 expression. Patients with tumours bearing high LDH-5 expression had a poor prognosis. Tumours with simultaneous LDH-5 and HIF1alpha (or HIF2alpha) overexpression, indicative of a functional HIF pathway, had a particularly aggressive behaviour. It is concluded that overexpression of LDH-5 is a common event in non-small-cell lung cancer, can be easily assessed in paraffin-embedded material and provides important prognostic information, particularly when combined with other endogenous markers of hypoxia and acidity.

Adult↗
PubMed2003

Imprint cytology for rapid evaluation of lung and mediastinal lesions.

BACKGROUND: Frozen-section biopsy (FSB) of pulmonary and mediastinal tumors is commonly used in the evaluation of diagnostic tissue in thoracic surgery. However, FSB can be labor intensive for the pathology department and time-consuming while the patient is anaesthetised. Imprint cytology is more rapid than the FSB procedure (average, 1 min versus 10 min per tissue sample) and allows more extensive sampling of the specimen. METHODS: In this preliminary study we compared the diagnostic accuracy of imprint cytology and permanent sections on lung and mediastinal lesions from 38 patients. RESULTS: There were no false-positive results and 2 false-negative results. The sensitivity was 99.13%, the specificity was 100% and the positive predictive value was 100%, as no false-positive results were observed. These results match favorably with those in other studies comparing the diagnostic accuracy of imprinting cytology with that of FSB and with reported accuracy rates of the FSB method. CONCLUSION: Our findings confirm the usefulness of this procedure as an adjunt or alternative for FSB in the pathologic evaluation of lung and mediastinal space-occupying lesions.

Adenocarcinoma↗
PubMed2002

Spontaneous pneumothorax resulting from congenital cystic adenomatoid malformation in a pre-term infant: case report and literature review.

In the literature there are only three reported cases of spontaneous pneumothorax resulting from congenital cystic adenomatoid malformation in children under 1 year and for whom any resuscitative efforts were made. We present here a fourth case of a pre-term baby girl who was in perfect health, until she suffered a spontaneous pneumothorax as the initial manifestation of congenital cystic adenomatoid malformation of the lung at 10 weeks of age. Atypical segmentectomy with the use of stapling devices was successful. The characteristics of this particular manifestation are discussed.

Cystic Adenomatoid Malformation of Lung, Congenita↗
PubMed2002

Immunocytochemical profile of malignant pleural effusions of small-cell lung cancer.

BACKGROUND: Small-cell lung carcinoma (SCLC) is a highly malignant tumour of a somewhat distinctive cell type. The aim of this study was to determine the immunocytochemical profile of tumor cells and lymphoid cell in SCLC pleural fluids. METHODS: Nine cases of malignant pleural fluids of SCLC were studied using cell block preparation. In pleural effusions cytologically proven to be malignant in 9 patients with SCLC, the immunocytological features of tumor cells, together with the determination of lymphocytic subsets were documented. RESULTS: In all 9 cases, tumor cells reacted with neuron-specific enolase (NSE) (100%), whereas in 6 of 9 cases (66,66%) tumor cell expressed synaptophysin, thyroid transciption factor-1 (TTF-1) and chromogranin A antigens. Phenotyping of the lymphocytes revealed in the majority of cases an expression of CD3 and CD4 antigens (8 and 7 cases, respectively) in contrast to CD8 and CD20 expression (1 and 1 case, respectively). CONCLUSIONS: The reactivity pattern of the tumor cells with the markers used in our study is a specific for SCLC. No significant difference in the distribution of lymphocytic subpopulations is observed in correlation with other malignant and no malignant processes involving the pleural cavity.

Antigens, CD↗
PubMed1995

Long-term surgical outcome of closed mitral commissurotomy.

Seven hundred and fifty-four patients who underwent closed mitral commissurotomy (CMC) between 1958 and 1993 (71% female, 29% male; mean age 39 years) for acquired mitral stenosis were reviewed postoperatively. Particular attention was given to those patients who later required mitral valve replacement (MVR). The total follow up experience was 9,607.9 years. Eighty-two patients (11%) needed a repeat CMC and 30% of these patients had subsequent MVR. In all, 146 patients (19, 3%) required MVR a mean of 17.0 years after commissurotomy (range one to 35 years). Preoperative factors associated with an unsatisfactory postoperative course and with later MVR included preoperative functional class, calcification of the mitral valve and subvalvular fusion. The adequacy of valvulotomy assessed at operation was also related to outcome. Postoperatively, poor functional improvement, congestive heart failure and the necessity for a repeat CMC were associated with late MVR. The indications for MVR were restenosis (59%), residual stenosis with or without mild mitral regurgitation (30%), and moderate to severe regurgitation (11%). Among survivors, 88% improved at least one functional class after MVR and the majority was free of congestive heart failure. It is concluded that CMC provides excellent long term clinical improvement in appropriately selected patients. The mean time interval of 17 years between CMC and late MVR reveals the efficacy of CMC to achieve satisfactory long term results.

Adolescent↗
PubMed1992

Reduction of CyA nephrotoxicity by nifedipine during and after experimental in situ renal preservation.

In order to evaluate the role of nifedipine in the nephrotoxic effect induced by both ischemia and CyA, 18 healthy mongrel dogs were used. The kidneys were exposed and subjected to 1 h of ischemia by clamping both renal vessels. To the renal artery of the first group of kidneys (n = 9), 300 mL of cold Euro-Collins solution, in which nifedipine (Bay a 1040-10 mg) was diluted, was infused for 15 min (nifedipine group), while 300 mL of cold Euro-Collins solution plus 10 mg of placebo (Bay a 1040-placebo) was infused to the renal artery of the second group (n = 9) of kidneys (placebo group). Venous drainage was effected through a plastic cannula. All animals received through a nasogastric catheter 20 mg/kg cyclosporine A at the beginning of the ischemia. The 1 h of ischemia was divided in a 15-min period of cold ischemia and 45-min of warm ischemia, at the end of which the clamps were removed. During the 2 h (30 min x 4) after reperfusion, 10 mg of nifedipine and placebo was administered additionally by a peripheral vein to the nifedipine and the placebo group, respectively. Then the kidneys were removed for histological study. Urine volume and creatinine and urea clearances of the nifedipine group were significantly higher than the placebo group (p < 0.001) while TxB2 levels were higher in the placebo group in all studied periods (p < 0.001). Urine sodium, FENa, osmolar clearance, and LDH values were significantly different (p < 0.01), but the urine potassium concentration was not different in the two groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1983

Mitral valve replacement with preservation of papillary muscles and chordae tendineae - revival of a seemingly forgotten concept. I. Preliminary clinical report.

In 45 consecutive patients mitral valve replacement was performed leaving the posterior mitral leaflet and its chordal attachment to both papillary muscles intact (Lillehei's technique). Most patients showed moderate to severe pulmonary hypertension before surgery, 15 of the patients had double valve operations and 4 had a triple valve procedure. All patients survived and were discharged, the postoperative courses being remarkably uneventful with only very limited need of inotropic support in 3 patients and resumption of spontaneous respiration within the first 20 hours after the operation. The clinical courses in these patients seem to indicate that preserving the continuity between papillary muscles and mitral annulus in mitral valve replacement may improve left ventricular function at least early after surgery.

Adult↗
PubMed1982

Valve replacement for chronic mitral insufficiency; long-term follow up using technetium pertechnetate scintigraphy.

Technetium Pertechnetate Scintigraphy was performed in 12 patients (9 men and 3 women, average age 48 +/- 13 years) on an average 19.8 +/- 11 months after valve replacement for chronic mitral insufficiency. Preoperative conventional ventriculography had revealed increased enddiastolic and endsystolic volumes (230.9 +/- 66 resp. 73.5 +/- 26 ml). 59.4 +/- 9% of the stroke volume (157.5 +/- 47 ml) regurgitated into the left atrium. Ejection-fraction (67.7 +/- 6%) was normal in all cases. Postoperative first pass technique was employed using a fast multicrystal camera (Baird Atomic, system 77). Volumes were assessed measuring normalized total count rate (count integral of the left ventricle divided by the maximum count density). 19.8 +/- 11 months after valve replacement enddiastolic and endsystolic volumes revealed normal at rest (121.8 +/- 38 resp. 52.8 +/- 35 ml) and after maximum exercise (122.0 +/- 29 resp. 37.6 +/- 22 ml). Ejection fraction responded physiologically to exercise by rising from 57.7 +/- 12 to 69.7 +/- 10%.

Adult↗