Using statins to reduce cardiovascular risk after carotid endarterectomy.
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Cardiovascular Diseases↗
Biomedical subjects
D Papadimitriou
Publications and source records attributed to D Papadimitriou.
Nuclear reprogramming and adult stem cell potential.
Cell-based therapy may represent a new strategy to treat a vast array of clinical disorders including neurodegenerative diseases. Recent observations indicate that adult somatic stem cells have the capacity to contribute to the regeneration of different tissues, suggesting that differentiative restrictions are not completely irreversible and can be reprogrammed. Cell fusion might account for some changed phenotype of adult cells but it seems to be biologically irrelevant for its extreme rarity. Other experimental evidences are compatible with the hypothesis of wide multipotency of well-defined stem cell populations, but also with transdifferentiation and/or dedifferentiation. Further studies on nuclear reprogramming mechanisms are necessary to fulfil the promise for developing autologous cellular therapies.
Adult↗
Structural and optical characterization of pyrolytic carbon derived from novolac resin.
The structural and optical properties of technologically interesting pyrolytic carbons formed from cured novolac resin and cured novolac/biomass composites were studied by X-Ray Diffraction Analysis (XRD), and Fourier Transform Infrared (FTIR), Raman and Photoluminescence (PL) spectroscopy. Pyrolysis of the cured materials took place at temperatures in the range 400-1000 degrees C. The most important weight loss, shrinkage and structural changes of pyrolyzed composites are observed at temperatures up to 600 degrees C due to the olive stone component. In the same temperature range, the changes in pyrolyzed novolac are smaller. The spectroscopic analysis shows that novolac pyrolyzed up to 900 ( degrees )C has less defects and disorder than the composites. However, above 900 ( degrees )C, pyrolyzed novolac becomes more disordered compared to the pyrolyzed composites. It is concluded that partial replacement of novolac by olive stone in the composite materials leads to the formation of a low cost, good quality product.
Biomass↗
Mycotic aneurysm of the infrarenal aorta.
The mycotic aneurysms of the infrarenal aorta (MAIA) are extremely rare and the associated morbidity and mortality is very high. The classification of infected aneurysms considers four types: a) true mycotic aneurysms, b) secondary mycotic aneurysms due to bacterial arteritis, c) infected preexisting abdominal aortic aneurysms and d) post-traumatic infected false aneurysms. The prognosis of true MAIA's is better than the other forms of infected aneurysms. The standard treatment includes the resection of the aneurysm and infectious surrounding tissues and the restoration of the flow using ex situ (axillobifemoral) bypass or in situ replacement with autologous vein or a rifampicinebonded graft. We present a case of mycotic aneurysm of the infrarenal aorta and a brief discussion of the alternative treatments from the relevant literature.
Aged↗
A survey of 14 computed tomography scanners in Greece and 32 scanners in Italy. Examination frequencies, dose reference values, effective doses and doses to organs.
A survey of examination frequencies, dose reference values, effective doses and doses to organs involving 14 scanners from Greece and 32 scanners from Italy was carried out for the years 1999 and 2000. Examination frequencies per scanner and per year were found to be 3590 for Greece and 4520 for Italy. For the types of examinations considered, CDTI(W) and DLP measurements were taken. Also scan lengths used for the same types of examinations were monitored. For the same types of examinations effective doses were calculated by two methods, and it was found that their mean values ranged from 13.1 mSv for thoracic spine to 1.6 mSv for the brain examinations. From the data of the 14 Greek laboratories, doses to organs were calculated and it was found that the thyroid receives 50.2 +/- 19.8 mGy during a cervical spine examination while the gonads receive 17.8 +/- 6.9 mGy during a routine pelvis examination.
Body Burden↗
Incidence of abdominal wall hernias in patients undergoing aortic surgery for aneurysm or occlusive disease.
BACKGROUND: The aim of this study was to compare the incidence of abdominal and incisional hernias in patients with abdominal aortic aneurysm (AAA) versus patients with aortoiliac occlusive disease (AOD). PATIENTS AND METHODS: The study included retrospectively 121 patients, who underwent elective aortic surgery due to AAA (n = 63) or AOD (n = 58) in the period between January 1998 and January 2000. The patients were examined for the presence of abdominal hernias upon admission, as well as for the development of incisional hernias on follow-up. RESULTS: The incidence of inguinal hernias was significantly higher in the group AAA (21/6-33.3%) compared to the group with AOD (6/58-10.3%) (p < 0.01). The incidence of other abdominal wall hernias (umbilical, epigastric or miscellaneous hernias) was also significant higher in AAA group. Furthermore, the incidence of inguinal hernias was significantly higher in the subgroup of patients with an aneurysm diameter more than 6 cm (41.5% vs 18.2%, p < 0.05). The mean follow-up of the patients was 1.7 +/- 0.3 years. 7 cases of incisional hernia were noted in the AAA group (11.1%) and only 2 cases in the AOD group (3.4%) (p < 0.05). The size of the aneurysm had no influence on the incidence of incisional hernias in the AAA group. CONCLUSION: We conclude that there seems to be an increased incidence of abdominal wall hernias as well as postoperative incisional hernias in patients undergoing aortic surgery for aneurysm disease compared with aortoiliac occlusive disease.
Aged↗
Allicin release under simulated gastrointestinal conditions from garlic powder tablets employed in clinical trials on serum cholesterol.
The failure of five recent clinical trials to show significant reduction in elevated serum cholesterol by a single brand of allicin-standardized garlic powder tablets is in contrast to many prior positive studies with the same brand. The hypocholesterolemic activity of garlic is mainly due to allicin, a compound that is produced by the acid-sensitive garlic enzyme, alliinase, only after tablet consumption. Therefore, the allicin-releasing ability of ten lots of these tablets--manufactured over the same years that the positive and negative clinical trials were conducted (1989-1997)--was determined under simulated gastrointestinal dissolution conditions, as defined by U.S. Pharmacopeia Method 724A. It was found that the older lots were more resistant to acid-disintegration (2.5 h vs. 1.3 h, P < 0.001) and that they released three times as much allicin (44% vs. 15 % of their potential, P < 0.001) as the newer lots. A second brand of tablets employed in a recent negative trial released no detectable amount of allicin, while a third set of tablets with high allicin release was used in a trial that gave positive effects. Hence, the persons involved in the recent negative clinical trials probably received considerably less allicin than did those in the older positive studies, possibly accounting for much of the discrepancy in the outcomes. In conclusion, clinical trials using garlic powder tablets to assess any effect of garlic that might be related to allicin, as most are, cannot be considered valid for garlic when the trial shows no effect, unless the expected allicin release from the tablets has at least been determined under standardized drug release conditions (USP 724A).
Cholesterol↗
Evaluation of fetal heart monitoring in the first stage of labor.
OBJECTIVE: To evaluate the usefulness of continuous electronic fetal heart rate (FHR) monitoring in the first stage of labor. METHODS: A total of 814 pregnant women in labor without identifiable risk factors was divided into two groups. In group A (468 cases), continuous FHR monitoring began in the earliest phase of the first stage of labor (cervical dilatation < or = 4 cm), while in group B (346 cases) it began when the cervical dilatation was > 4 cm. Initial FHR tracings were normal in all 814 cases. The fetal monitoring findings were analyzed at 10-min intervals, and comparisons were made between the two groups concerning FHR findings and their correlation with the state of the newborns. RESULTS: No significant difference was found between the two groups in the incidence of repetitive variable decelerations (1.9% and 1.7%, respectively); sporadic variable decelerations (9.2% and 8.7%, respectively); persistent repetitive late decelerations that resulted in Cesarean section (1.1% and 1.4%, respectively); or sporadic late decelerations (8.3% and 8.1%, respectively). One newborn from each group required intensive neonatal care. CONCLUSIONS: The same tracing sufficiency of fetal stress was observed in the two groups. However, the manner of labor supervision in group B seemed to be more beneficial, because of greater maternal comfort, a lower necessity for personnel, lower consumption of cardiotocographic materials and the possibility of labor induction for more women. Since fetal monitoring is widely used, it is preferable to start continuous FHR monitoring when the dilatation of the cervix approximates 4-5 cm (second phase of the first stage of labor) without risk of fetal loss.
Adolescent↗
Intercomparison of TL dosimetry (DIMOND programme).
During DIMOND CA, a thermoluminescence dosimetry intercomparison has been performed, in order to ensure that all participants measure the same dose. After the calibrating and annealing procedures, 50 TLD pellets (in groups of five) of each participating country were sent to the coordinator to be irradiated with 'unknown' radiations (blind test). The irradiation conditions (8 different set-ups, one for each group of pellets per participant) were (i) one gamma irradiation (60Co), at air kerma in the range of 0.3 to 50.0 mGy, (ii) seven X ray irradiations, at air kerma in the range of 0.3 to 50.0 mGy, with tube potential in the range of 40 to 150 kV and a variety of filter combinations. Ten pellets (two groups) were used for background and transport dose evaluation. After measuring the TLDs, the participants sent the results to the coordinator for intercomparison. Irradiating set-up conditions, evaluated doses, as well as comparison of mean values with the 'true' nominal doses are presented and discussed.
Gamma Rays↗
Patient dose, image quality and radiographic techniques for common X ray examinations in two Greek hospitals and comparison with European guidelines.
The radiographic technique factors and the quality of each radiographic image for three common examinations (chest PA, pelvis AP and lumbar spine LAT) were compared with the European criteria and entrance surface dose (ESD) was measured for each radiograph in two Greek hospitals. The measurements were carried out using calibrated LiF thermoluminescence dosemeters. The patients were selected so that their weight was close to 70 +/- 10 kg and their height to 170 +/- 10 cm. Effective dose values were calculated using a PC-based Monte Carlo program. All four X ray rooms in the survey achieved mean doses well below the European reference doses. However the mean doses in the X ray rooms differed by a factor of about 3.
Dose-Response Relationship, Radiation↗
Application of European Commission reference dose levels in CT examinations in Crete, Greece.
The purpose of this study was to apply European Commission reference dose levels (EC RDLs) to routine CT examinations. The dosimetric quantities proposed in the European Guidelines (EG) for CT are weighted computed tomography dose index (CTDI(w)) for a single slice and dose-length product (DLP) for a complete examination. Patient-related data as well as technical parameters for brain, chest, abdomen and pelvis examinations were collected for four CT scanners in the Euromedica Medical Center. Computed tomography dose index (CTDI) measurements were performed on each scanner and CTDI(w), DLP and effective dose E were estimated for each type of examination for a random sample of 10 typical patients. Mean values of CTDI(w) had a range of 27.0-52.0 mGy for brain and 13.9-26.9 mGy for chest, abdomen and pelvis examinations. Mean values of DLP had a range of 430-758 mGy cm for brain, 348-807 mGy cm for chest, 278-582 mGy cm for abdomen and 306-592 mGy cm for pelvis examinations. Mean values of E were 1.4 mSv for brain, 10.9 mSv for chest, 7.1 mSv for abdomen and 9.3 mSv for pelvis examinations. Results confirm that the Euromedica Medical Center meets EC RDLs for brain, abdomen and pelvis examinations, in terms of radiation dose and examination technique. As far as chest examination is concerned, although CTDI(w) of each scanner is within proposed values, the DLP is consistently exceeded, probably because of the large irradiation volume length L. It is anticipated that a reduction of L, or product mAs, or their combination, will reduce DLP without affecting image quality.
Brain↗
Alterations in carbon dioxide release during abdominal aortic clamping for aneurysmal or occlusive repair.
BACKGROUND: Application and removal of an infrarenal aortic clamp is associated with changes in oxygen consumption, especially when collateral perfusion is limited. Carbon dioxide production during abdominal aortic clamping is expected also to change. The aim of this study was to evaluate the alterations of CO2 release during abdominal aortic surgery. METHODS DESIGN: prospective study. SETTING: University Hospital, Greece. PATIENTS: 17 patients undergoing abdominal aortic aneurismal (AAA) repair and 8 patients undergoing repair of aortoiliac occlusive disease. INTERVENTION: intraoperative record or calculation of PaCO2, PetCO2, PECO2, VD, VDalv, and VCO2. Patients with aneurysms were randomly divided to have constant ventilation (group AA) or modified ventilation to preserve normocapnia (group AB) during clamping. Ventilation was kept constant in the occlusive patients group (group OD). RESULTS: Patients with AAA showed a significant decrease of VCO2 during clamping and an elevation after unclamping in both groups (AA and AB), with no difference of statistical importance between them. During clamping, PetCO2/ PaCO2 ratio was decreased and VDalv was increased especially in group AA, while unclamping produced the opposite effect. Occlusive patients showed insignificant alterations. CONCLUSIONS: Our results suggest that, the calculated alveolar dead space is only an indicator of the true V/Q in patients with AAA, because it is strongly dependent on the CO2 load to the lungs, which is markedly altered in the same period. The modification of ventilation during clamping based only on PetCO2 and not on arterial sampling, could possibly lead to hypercarbia in these patients.
Aged↗
Continuous contralateral jugular acid-base and blood gas monitoring during carotid endarterectomy.
BACKGROUND: The aim of this study is to evaluate the intravascular multiparameter sensor Paratrend 7 (P7) for continuous acid-base and blood gas monitoring after retrograde jugular catheterization during carotid endarterectomy. PATIENTS AND METHODS: We studied 11 patients with history of smoking (72.7%), coronary artery disease (72.7%), hypertension (100%), diabetes mellitus (55.5%) and TIA's and/or nondisabling stroke (90.9%). The contralateral internal jugular vein was punctured retrogradely and the calibrated P7 sensor was introduced. The sensor was removed after surgery. The P7 provides continuous graphical display of pH, pCO2, and pO2, while temperature, oxygen saturation, HCO3 concentration and base excess are displayed numerically. RESULTS: Mean duration of carotid cross-clamping was 17.0 +/- 6.2 min. Mean stump pressure was 50.2 +/- 12.9 mmHg. Intraluminal shunting was not used in any operation. All sensors were easily inserted. During clamping, pH became persistently more acidic (7.31 to 7.28; p < 0.05), pCO2 was elevated (44.7 to 49.8 mmHg; p < 0.05) while, in the majority of the patients, there was a non significant decrease in pjvO2/SjvO2. Declamping was followed by a short period of decrease of pH and elevation of pCO2 reminiscent of wash out phenomena. PjvO2 was significantly elevated (53.8 +/- 5.2 to 59.0 +/- 5.8 mmHg; p < 0.001) after the restoration of flow. In one case, P7 was diagnostic for unsuccessful endarterectomy. CONCLUSIONS: P7 is useful during carotid endarterectomy providing continuous and "on-line" information on brain metabolism. It is a simple and powerful technique, which should be further investigated.
Acid-Base Equilibrium↗
Carbon tetrachloride modulates the rat hepatic microsomal UDP-glucuronyl transferase activity and membrane fluidity.
Modulations in rat hepatic microsomal UDP-glucuronyl transferase activity have been observed during carbon tetrachloride (CCl4) poisoning, with a large decrease in the enzyme cooperatively and increase in the membrane fluidity, occurring 30 min after administration. The results strengthen the possibility that an increase in microsomal membrane fluidity may be an early key event in liver injury induced by CCl4.
Allosteric Regulation↗
Shock-front-stimulated optical scattering in water.
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Journal Article↗
Compatibility of amphotericin B with certain large-volume parenterals.
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Amphotericin B↗
Reduced dialysis of nitrofurantoin and hydrocortisone acetate from methylcellulose solutions.
Factors affecting reduction in the permeation rate of nitrofurantoin and hydrocortisone acetate from methylcellulose solutions through a cellulose membrane were investigated. The factors evaluated were the effect of polymer agglomeration and whether the drugs formed a complex with the polymer. The influence of polymer agglomeration was evaluated by dynamic dialysis studies of nitrofurantoin dissolved in solutions of methylcellulose 400 cps, which agglomerates, and in methylcellulose 50 cps, which does not exhibit this behavior. Dialysis rates of this drug were measured as a function of polymer concentration, ionic strength, heating time prior to measurement, and temperature. The effect of polymer agglomeration on the permeation rates of hydrocortisone acetate was studied by varying the ionic strength of the drug-polymer solution. Complex formation studies were conducted for both drugs by the equilibrium dialysis method. Polymer agglomeration caused a substantial reduction in the dialysis rate of both drugs in methylcellulose 400 cps solutions. There was less reduction in the dialysis rate of nitrofurantoin with increased polymer concentration of methylcellulose 50 cps solutions, which was attributed to the increase in the bulk viscosity of the solution. There was no evidence of complex formation of the drugs with the polymers.
Chemical Phenomena↗
Colorimetric determination of penicillins and related compounds in intravenous solutions by nickel (II)-catalyzed hydroxamic acid formation.
Solutions of ampicillin, carbenicillin, methicillin, oxacillin, penicillin G, and cephalothin in 5% dextrose were analyzed by nickel(II)-catalyzed hydroxylaminolysis. The reactions of these antibiotics were complete within 20 min at room temperature. Under the analytical conditions, molar absorptivities of the ferric-hydroxamate complexes ranged from 830 to 1005 liters/mole/cm. Coefficients of variation for the analysis of these antibiotics in 5% dextrose were typically less than 3% at concentrations of 1 mg/ml. Oxacillin was analyzed by the same method in normal saline and/or lactated Ringer solutions. The method also was applied to the analysis of chloramphenicol in aqueous solutions. Only ampicillin showed a significant decrease in concentration in 48 hr.
Catalysis↗