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C Politis

Publications and source records attributed to C Politis.

At least 19 recordsLinked to original sources
PubMed2005

Tooth transplantations: a descriptive retrospective study.

The aim of the present study was to perform a retrospective study of autogeneously transplanted teeth in order to examine the influence of clinical criteria such as the type of the donor tooth, the root length at the time of transplantation, donor eruption stage and others on the overall success rate of the transplantation. The material of this study consisted of 194 patients in whom 273 teeth were transplanted. The mean age at the time of autotransplantation was 18.1 years with a standard deviation of 7.5 years. Transplantations were performed in two hospitals. The follow-up period varied from 15 days to 11 years, and the mean follow-up time was 3.8 years. 58/273 teeth showed one or other form of resorption, 37/273 teeth showed ankylosis, 30/273 showed no important changes in pulp chamber size, 104/273 showed major discoloration after transplantation, 92/273 teeth showed positive results for cold test after transplantation and 26/273 teeth showed clinically unacceptable pocket depth. Clinical and radiological evaluations were performed. An association was found between successful transplantation and donor tooth type (P<0.01), root length at the time of transplantation (P<0.0001) and recipient tooth site (P=0.03). There was a borderline association between successful transplantation and donor eruption stage (P=0.05). In conclusion, autotransplantation of teeth performed with a careful surgical procedure at the stage of 1/2-3/4 of their intended or expected root length can render a very useful service to patients.

Adolescent↗
PubMed2004

An update on predeposit autologous blood donation and transfusion in Europe.

BACKGROUND AND OBJECTIVES: The aim of this study was to update previous data on the practice of autologous blood transfusion in Europe. MATERIALS AND METHODS: A questionnaire, mainly about predeposit, was distributed to each National Representative on the Council of Europe's Committee of Experts on Blood Transfusion and Haematology. Detailed replies were received from 23. RESULTS: Predeposit autologous blood units collected in 2000 amounted to 3.3% of the allogeneic units, compared with 4.2% in 1997. Predeposit collection was commonest in Italy (7.8%) and Germany (6.4%). CONCLUSIONS: Although autologous transfusion showed no sign of increase in Europe from 1997 to 2000, the need for alternatives to allogeneic transfusion is growing. Policy and practices in this field should be followed on an ongoing basis.

Blood Donors↗
PubMed2003

Image-based planning and clinical validation of zygoma and pterygoid implant placement in patients with severe bone atrophy using customized drill guides. Preliminary results from a prospective clinical follow-up study.

The zygoma implant has been designed for those situations where there is insufficient bone in the upper jaw, which would otherwise require onlay or inlay (sinus) bonegrafts. The aim of the study was to present and validate a planning system for implant insertion based on preoperative CT imaging. It allows the surgeon to determine the desired position of different kinds of implants. Finally a customized drill guide is produced by stereolithography. In this study, zygoma, pterygoid and regular platform implants were used. The treatment protocol is validated through 12 case studies, selected at random from the total patient group (n=29 patients). From postoperative images, the exact implant location is determined and the deviation of axes between planned and inserted implants is calculated. In this in vivo study, displacements, varying according to the type of implant and the location of the implants, were observed. From a clinical standpoint, most of the inserted implants were judged to be adequately sited. A prospective clinical follow-up study was performed on all 29 patients. Although all patients presented with severe maxillary atrophy, excellent cumulative survival rates (92%) for the zygoma implants and 93% for regular platform implants have been obtained.

Adult↗
PubMed2001

An inhibitor of mTOR reduces neoplasia and normalizes p70/S6 kinase activity in Pten+/- mice.

PTEN phosphatase acts as a tumor suppressor by negatively regulating the phosphoinositide 3-kinase (PI3K) signaling pathway. It is unclear which downstream components of this pathway are necessary for oncogenic transformation. In this report we show that transformed cells of PTEN(+/-) mice have elevated levels of phosphorylated Akt and activated p70/S6 kinase associated with an increase in proliferation. Pharmacological inactivation of mTOR/RAFT/FRAP reduced neoplastic proliferation, tumor size, and p70/S6 kinase activity, but did not affect the status of Akt. These data suggest that p70/S6K and possibly other targets of mTOR contribute significantly to tumor development and that inhibition of these proteins may be therapeutic for cancer patients with deranged PI3K signaling.

Alleles↗
PubMed2001

Autologous blood donation and transfusion in Europe.

BACKGROUND AND OBJECTIVES: The aim of this study was to record practices in autologous blood transfusion in Europe in 1997. MATERIALS AND METHODS: A questionnaire mainly about predeposit was distributed to the National Representatives of all 41 member states of the Council of Europe's Committee of Experts on Blood Transfusion and Haematology. Replies were received from 29. RESULTS AND CONCLUSION: Autologous blood units collected in 1997 amounted to 4.2% of the allogeneic units, with wide variations between countries. Predeposit was used most frequently in Italy (8.9%), Germany (7.1%) and France (6.6%). Some countries, notably Scandinavia, do not encourage predeposit, chiefly on the grounds that it is not cost-effective, but others are promoting its use.

Blood Banks↗
PubMed2001

Seizures in the critically ill: the role of imipenem.

PURPOSE: To determine the risk of seizures in critically ill patients receiving the antibiotic imipenem, a broad-spectrum antibiotic that has been associated with seizures. Reports generally have not considered other contributing factors such as dose, seizure history, and morbidity index of the underlying illness necessitating the antibiotic. METHODS: Charts of all patients in a 450-bed municipal hospital who received imipenem in a 6-month period, as determined by pharmacy records, were reviewed for dosage and duration of imipenem use, occurrence of seizures. and mortality outcome. Attention was paid to demographic features; pattern of seizure occurrence during, before, and after imipenem use; renal function; and correction for dosage based on size. RESULTS: Seventy-five charts were reviewed. Sixty-three patients had no seizures during the hospitalization, four had seizures while receiving imipenem, and eight had seizures during the hospitalization but before or after imipenem use. The incidence of seizures was 4/1,000 patient-days on, and 3.9/1,000 patient-days off imipenem (not significant). The risk of seizure in both groups was considerably higher in those patients with a history of seizures before hospitalization. The presence of other factors that could contribute to increased concentration of imipenem in the brain, such as renal failure or acute stroke, did not contribute to seizure incidence. Metabolic derangement, anoxia, and phenytoin discontinuation did contribute to seizure incidence. CONCLUSIONS: Seizure incidence is increased in all critically ill patients (16% of patients studied), but with no added risk during the period patients received imipenem. Determining the proper dose based on a patient's body mass, correction of dose in the presence of renal failure, and avoidance of excess of 2 g/day of imipenem removes any added risk for seizures from imipenem. Despite experimental data to suggest action of imipenem on the glutamate/N-methyl-d-aspartate receptor, or interference with binding to the gamma-aminobutyric acid receptor, and early clinical studies that warned against its use because of seizure risk, we found that careful use of this antibiotic is safe.

Acute Disease↗
PubMed2001

Skeletal and dento-alveolar stability after surgical-orthodontic treatment of anterior open bite: a retrospective study.

The aim of this investigation was to assess skeletal and dento-alveolar stability after surgical-orthodontic correction of skeletal anterior open bite treated by maxillary intrusion (group A) versus extrusion (group B). The cephalometric records of 49 adult anterior open bite patients (group A: n = 38, group B: n = 11), treated by the same maxillofacial surgeon, were examined at different timepoints, i.e. at the start of the orthodontic treatment (T1), before surgery (T2), immediately after surgery (T3), early post-operatively (+/- 20 weeks, T4) and one year post-operatively (T5). A bimaxillary operation was performed in 31 of the patients in group A and in six in group B. Rigid internal fixation was standard. If maxillary expansion was necessary, surgically assisted rapid palatal expansion (SRPE) was performed at least 9 months before the Le Fort I osteotomy. Forty-five patients received combined surgical and orthodontic treatment. The surgical open bite reduction (A, mean 3.9 mm; B, mean 7.7 mm) and the increase of overbite (A, mean 2.4 mm; B, mean 2.7 mm), remained stable one year post-operatively. SNA (T2-T3), showed a high tendency for relapse. The clockwise rotation of the palatal plane (1.7 degrees; T2-T3), relapsed completely within the first post-operative year. Anterior facial height reduction (A, mean -5.5 mm; B, mean -0.8 mm) occurred at the time of surgery. It can be concluded that open bite patients, treated by posterior Le Fort I impaction as well as with anterior extrusion, with or without an additional bilateral sagittal split osteotomy (BSSO), one year post-surgery, exhibit relatively good clinical dental and skeletal stability.

Adolescent↗
PubMed2001

A worldwide analysis of AG molecular diversity inferred from serology.

Ten population samples from different geographic origins were tested serologically for the AG polymorphism of human beta-lipoproteins. Their haplotype frequencies were used with previously published data to perform a wide analysis of AG genetic differentiations throughout the world. Coancestry coefficients were computed from weighted F(ST)s among populations by using a matrix of molecular distances among AG haplotypes, which is here determined on the basis of DNA studies. Coancestry coefficients derived from unweighted F(ST)s and more classical Prevosti distances were computed on the same data and used for a comparison. In all cases a highly significant correlation was found between genetics and geography on a worldwide scale, while the significance of the correlation with linguistics differed. A test of significance of the pairwise F(ST)s among populations also gave different results depending on whether the molecular distance matrix among AG haplotypes was included. Globally, this study shows that in spite of being highly significantly correlated to each other, different genetic distance measures can lead to different interpretations of the same data set. Moreover, the elucidation of the molecular models related to the presently known serological polymorphisms may represent an additional tool for analyzing such polymorphisms in human population genetics studies.

Amino Acid Substitution↗
PubMed1998

The psychosocial impact of chronic illness.

Depending on the severity of thalassemia and the level of health care provided, the thalassemic person may suffer from his/her chronic condition going through the path: disease-->impairment-->disability-->handicap. There is evidence that a high clinical burden is associated with a psychosocial burden for the patients and the family. In Greece, support strategies have developed in the last twenty years to help the thalassemic patient and his/her family. Recent studies in 909 patients show that the life span is prolonged (mean age 27 years), 83% of the patients study or work, 12% are married and 2.3% have set up a family, and 98% utilize the social benefits provided (free education, free entrance to universities, tax allowances, cash benefit, early retirement, etc.). However, psychometric tests performed in 131 patients and 65 matched normal controls over 14 years of age have shown that hostility (extroverted, delusional, total p < 0.001) is an important component of the psychological profile of the patients. The patient's role through their association is strong and undoubtedly has influenced the public's extremely high (93%) awareness of the basic features of the disease and the supportive attitude of the average Greek citizen toward the life style of the thalassemic patient. On the whole, in many thalassemic patients illness has overpowered all other aspects of life. For few, however, life is much more than an illness. Shouldn't this be the message for the patient's psychosocial support strategies?

Adaptation, Psychological↗
PubMed1998

T2 relaxation time study of iron overload in b-thalassemia.

Myocardial iron deposition occurs as a result of blood transfusion therapy in b-thalassemia major patients. Since this deposition causes various cardiac complications, it is of interest to assess the iron content of the myocardium in relation to the clinical picture of the patients. Two different MRI indices were used to achieve this purpose: the T2 relaxation time and the heart/skeletal muscle signal intensity ratio. ECG gated spin echo images were obtained from 54 adult thalassemic patients, with a mean age of 26 (18-44) years, at TE = 22 ms and 60 ms, using a 1.5 T system. Patients were divided into 2 groups (A and B), according to their serum ferritin levels (> or < 2000 ng ml(-1)). Results were compared with nine controls, with a mean age of 25 (18-43) years. Heart T2 relaxation time in controls (44.3 +/- 3.5 ms) was higher than in group A (29.9 +/- 5.7 ms, P < 0.001) and group B (33.4 +/- 6.8 ms, P < 0.01). T2 was measurable in 66% of group A and 83% of group B patients. The heart/muscle signal intensity ratio in group A (0.45 +/- 0.27) was lower than in group B (0.82 +/- 0.33, P < 0.001) and the controls (1.15 +/- 0.20, P < 0.001). The heart/muscle signal intensity ratio was measurable in 94% of the patients and demonstrated an inverse relationship with the serum ferritin levels (r = -0.52, P < 0.01). This study indicates that the heart/muscle ratio is a sensitive index of iron overload and it can be measured in the majority of patients, irrespective of tissue iron concentration, thereby offering an advantage over the use of T2 relaxation time.

Adolescent↗
PubMed1995

Cryopreservation of teeth. Organizational aspects of a tissue bank for tooth tissues.

Cryopreservation of teeth became possible since a better understanding of the cryoprotective mechanism of cosolvents such as dimethylsulfoxide (DMSO). The high number of extractions of healthy teeth performed for orthodontic reasons, i.a., gives a sufficient amount of donor teeth. The organization and quality control of a tissue bank for teeth tissues is legally regulated. This paper highlights some of the key-issues of these stipulations.

Cryoprotective Agents↗