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  • 1
    ISSN: 1432-0533
    Schlagwort(e): Key words p21 ; p53 ; Astrocytoma ; Single-strand ; conformation polymorphism ; Immunohistochemistry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Approximately one quarter of human astrocytomas show immunohistochemical positivity for p53 protein but lack p53 gene mutations, which could reflect either an accumulation of wild-type p53 protein or an inadequate sensitivity of mutation detection. Since wild-type p53 up-regulates p21 expression, increased p21 expression in those astrocytomas with p53 accumulation in the absence of mutations would argue that the protein was wild type in these tumors. We therefore compared p21 expression with p53 gene and protein status in 48 primary human astrocytomas. Single-strand conformation polymorphism analysis and direct sequencing of the p53 gene showed mutations in 11 tumors (22.9%), while immunohistochemistry revealed positive staining in 19 cases (39.6%). Those tumors with p53 immunopositivity in the absence of p53 mutation had significantly increased p21 expression when compared to either mutant p53 or p53-immunonegative cases. Neither p53 nor p21 status correlated with proliferation indices, as assessed by Ki-67 immunohistochemistry. These results support the hypotheses that functionally wild-type p53 accumulates in some astrocytomas, and that alternative cell cycle checkpoints (such as the p16 pathway) may be more important than p21 in regulating proliferation in astrocytomas.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    ISSN: 1436-2813
    Schlagwort(e): postoperative cardiac functions ; cardiac index ; stroke index ; left ventricular stroke work index ; left ventricular minute work index ; extracorporeal circulation ; preoperative NYHA classification
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Effectiveness of only left coronary perfusion on myocardial protection was assessed by measuring serially cardiac functions such as cardiac index(CI), stroke index(SI), left ventricular minute work index(LVWI) and left ventricular stroke work index (LVSWI) in 22 consecutive patients with isolated, scheduled aortic valve replacement. The cardiac functions were determined 2,4 and 6 hours after open heart surgery. Correlation coefficients(r) between coronary perfusion time and the cardiac functions were less than 0.23, such being statistically insignificant. SI and LVSWI were in statistically significant inverse correlation to the preoperative NYHA classification and extracorpreal circulation(ECC) time for 4 hours following open heart surgery, and CI and LVWI for 2 hours. The correlation coefficients were highest at the 2nd postoperative hour and then decreased with passage of time. Therefore, the cardiac dysfunctions occurring in the postoperative period correlated either to the preoperative NYHA classification or ECC time, or both. It does, however, seem likely that the dysfunctions were correlated to ECC time as the recovery time of 4 hours from the dysfunctions is too short for preoperatively existing dysfunction. Therefore, it was concluded that the continuous perfusion of only the left coronary artery was not the determinant factor of the postoperative dysfunctions and that the ECC time afforded detrimental effects, although such continued for 4 hours in terms of SI and LVSWI, and 2 hours in term of CI and LVWI.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    ISSN: 1436-2813
    Schlagwort(e): operation ; operative technique ; suturing ; beneficial effect of forceps on suturing ; needle handling
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Ideal suturing was defined as advancing a needle along its curvature (needle circle) to minimize tissue trauma, while placing the suture with its intended span and tissue bite in the expected place. Actual suture tracks were analyzed to find the keys to produce such suturing. Correspondence of those tracks to the ideal track was then determined by the span, the initial needle angle (IA) into the tissue, and the center of the needle circle. Eight surgeons with 4–7 years of experience produced 22 ideal sutures in two types of tissue simulants: The entrance and exit points of the needle were level in flat suturing, while the entrance point was slanted 45 degrees for slant suturing. The correspondence was better with slant suturing than flat suturing (P〈0.01). The IA in flat suturing was 49.0±2.0 (mean±SE) degrees versus 33.0 for ideal suturing (P〈0.01), while that in slant suturing was 35.5±1.9 (P: ns). In conclusion, the IA was the key to good results, and was optimized in slant suturing, which was instinctively utilized in practice by using forceps. The forceps avoided a derangement of suturing stemming from the configuration of the needle employed and from the range of motion of the surgeon's arm (human engineering), while satisfying the surgeons inclination to take a large IA.
    Materialart: Digitale Medien
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  • 4
    Digitale Medien
    Digitale Medien
    Springer
    Surgery today 17 (1987), S. 465-469 
    ISSN: 1436-2813
    Schlagwort(e): suture ; surgical technique ; experience in surgery
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The pinpoint accuracy in the suturing techniques of 35 surgeons was measured by the distance deviated from an expected needle exit. The grip of the needle holder used by the surgeons was their habitual one. Accuracy was tested using two ways of suturing; namely with, and without wavering a needle to aim at an exit after suturing began. Where the surgeons did not waver the needle, accuracy improved both when the surgical experience was greater than one year (p〈0.05) and again when the experience exceeded 10–15 years (not significant). Difference of the accuracy between individual surgeons disappeared in those surgeons with 15 to 20 years experience. Where the surgeons wavered the needle, improvement was more marked in the former period and less in the latter. Wavering improved the accuracy in each group (p〈0.01), but with the possible danger of injuring tissue. In conclusion, accuracy was not as precise as most surgeons' confidence believed. A significant improvement was observed with 1-year experience, but the improvement thereafter was poor. Fifteen to 20 years experience was not enough to acquire a suturing technique not necessitating needle wavering in the tissue, still yielding a 1.7 mm deviation in a 2 cm suture-stride. It was however enough to eliminate surgeons' individual differences in accuracy.
    Materialart: Digitale Medien
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  • 5
    ISSN: 1436-2813
    Schlagwort(e): epinephrine ; dopamine ; norepinephrine ; cardiac index ; stroke index ; open heart surgery
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Serum catecholamines (epinephrine, dopamine and norepinephrine) were measured two, four and six hours after open heart surgery. The ratios of stroke index (SI) and cardiac index (CI) to catecholamines (CA) were determined. Patients studied consisted of 27 with congenital and 14 with acquired heart disease. Extracorporeal circulation (ECC) time was longer than 90 minutes in 17 and shorter in 24 patients. SI and CI diminished in elder patients with congenital disease (Group Cg-ad), patients with acquired desease (Group Ac) and patients with a longer ECC time (Group L). Therefore, elder age and/or longer ECC time seems to be responsible to the lower indices. However, the ratios of the indices to CA showed that the lower indices indicated the poor response of the myocardium to CA in Group Ac and Group L. The response was larger in Group Cg-ad and the lower indices were related to lower serum CA level. It was concluded, therefore, that the indices of stroke volume and cardiac output had inverse correlation to ECC time, but not to age, namely, prolonged ECC compromised more severely the myocardium and resulted in the poor response of the myocardium to CA. Subsequently, to compensate for the poor response, serum CA levels were elevated probably to maintain due SI and CI in patients with prolonged ECC.
    Materialart: Digitale Medien
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  • 6
    ISSN: 1436-2813
    Schlagwort(e): Low output syndrome ; subendocardial hemorrhagic necrosis ; myocardial protection ; intermittent aortic crossclamping ; coronary perfusion ; stroke index ; cardiac index
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Twenty-seven patients undergoing open-heart surgery were divided into three groups, i.e., control, intermittent aortic crosslamping and coronary perfusion groups. Myocardial oxygen extraction, lactate extraction, arterial-coronary sinus hydrogen ion difference, potassium difference and glucose difference were determined during the operation, as well as, postoperative stroke and cardiac indices and comparisons were made. When the ascending aorta was not crossclamped, myocardial metabolism was well preserved during and after the perfusion at a flow rate of 2.0 L./min/m2. Intermittent aortic crossclamping for 15 minutes alternating with a period of perfusion for five minutes at 30°C was sufficient to protect the myocardium from ischemia. Perfusion of the left coronary artery alone at a flow rate of six per cent of total body perfusion (150 to 200 ml per minute) at 30°C was sufficient to protect the myocardium when the aorta was opened. Since intermittent perfusion of the left coronary artery may produce myocardial derangement, coronary perfusion should be continuous. Otherwise topical cardiac cooling or other means of myocardial protection should be used.
    Materialart: Digitale Medien
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  • 7
    ISSN: 1573-7373
    Schlagwort(e): APEX nuclease ; AP endonuclease ; DNA 3′ repair diesterase ; cellular sensitivity to genotoxic agents ; glioma cells (human)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The multifunctional DNA repair enzyme (APEX nuclease) having apurinic/apyrimidinic (AP) endonuclease, 3′-5′ exonuclease, DNA 3′ repair diesterase and DNA 3′-phosphatase activities is thought to be involved in repair of AP sites and single-strand breaks with 3′-blocked termini. To investigate the biological role of the enzyme, we studied the correlation between APEX AP endonuclease activity in several human glioma cell lines having various degree of its expression and cellular susceptibility to cytotoxic agents such as methyl methanesulfonate (MMS), 1-(4-amino-2-methyl-5-pyrimidinyl)methyl-3-(2-chloroethyl)-3-nitrosourea hy-drochloride (ACNU), cis-diamminedichloroplatinum(II) (CDDP), etoposide (VP-16), hydrogen peroxide (H2O2), hyperthermia and X-ray. The cell lines having lower APEX expression showed higher sensitivity to MMS and H2O2 which are known to induce AP sites and single strand breaks on DNA, respectively. The cellular susceptibility to the other agents tested was not significantly correlated to the APEX expression. The present results are thought to support the notion that APEX nuclease plays an important role on repair of AP sites and single-strand DNA breaks with 3′-blocked termini in mammalian cells.
    Materialart: Digitale Medien
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  • 8
    Digitale Medien
    Digitale Medien
    Springer
    Surgery today 19 (1989), S. 424-431 
    ISSN: 1436-2813
    Schlagwort(e): operative technique ; suture ; surgeon’s skill ; training of the surgeon
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The suturing techniques of fifteen surgeons with similar surgical experience were evaluated with respect to pinpoint accuracy and the force produced while suturing. Subjects were randomly selected from a group of surgeons whose surgical experience ranged from five to six years. Accuracy was determined by the deviated distance between the needle exit and the designated exit. Force was expressed as torques (F) loaded on a needle holder, and included the derivatives (dF/dt) and integrals (IF). Suturing times (T) were also measured. Ten attempts at suturing were allowed, using each of the following two methods: 1) allowing adjustment by wavering the needle to improve accuracy, and 2) suturing without wavering the needle. The differences in technique, on an individual basis, were highly significant. The accuracy and the mechanics, including the maximum F, maximum dF/dt, IF, IF/T, and T, all had a p-value of less than 0.0001. The surgeons’ ranks according to these variables were also concordant, the Kendall’s coefficients of concordance (W) being 0.60 (p=0.002) for suturing done without wavering and 0.56 (p=0.005), for that done with wavering. It was concluded that the surgeons’ skill in suturing techniques differed significantly among individuals and that the surgeons’ ranks according to the variables were also concordant. Thus, formal training in suturing techniques should be established as part of the training of all surgeons.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 9
    Digitale Medien
    Digitale Medien
    Springer
    Surgery today 17 (1987), S. 123-129 
    ISSN: 1436-2813
    Schlagwort(e): diabetes mellitus ; hyperosmolar hyperglycemic non-ketotic diabetic coma ; hypoxemia ; open heart surgery ; pulmonary dysfunction
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The ratio of PaO2 to FiO2 was often low (300 or less) in four patients with complications of hyperosmolar hyperglycemic non-ketotic diabetic coma (HHNKDC) following open heart surgery. Four of our patients had poor oxygenation and subsequent spontaneous recovery from in the immediate post-operative period, although HHNKDC occurred only in one during this period. In the 3 others, poor oxygenation without accompanying HHNKDC lasted for 1–6 days and HHNKDC developed about 2 weeks after open heart surgery at time when poor oxygenation reoccurred. If a working diagnosis of congestive heart failure was made only on the basis of the most common probability, and the fluid supply was restricted, HHNKDC would readily occur or be aggravated by the dehydration iatrogenically produced. It is thus concluded that HHNKDC should be included in diagnoses for pulmonary dysfunction.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 10
    ISSN: 1436-2813
    Schlagwort(e): diabetes mellitus ; ischemic heart disease ; coronary artery bypass grafting ; pulmonary oxygen transfer ; arterial/alveolar oxygen tension ratio
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The objective of this study was to determine the effects of a diabetic disposition on pulmonary gas exchange by examining 72 patients who underwent coronary artery bypass grafting (CABG), using the arterial/alveolar oxygen tension ratio [(a/a)Po 2] as a criterion. Patients were divided into a diabetic (DM) group and a nondiabetic (non-DM) group. The postoperative blood gases and hemodynamic data measured when the blood glucose level was at a maximum on the day of CABG were used as the postoperative pulmonary gas exchange indices, and the physicians who managed these patients were unaware of this study. The preoperative (a/a)Po 2 ratio was 0.66±0.03 (SE) in the DM group and 0.78±0.02 in the non-DM group (P〈0.01), while the postoperative ratios were 0.42±0.03 and 0.52±0.03, respectively (P=0.01). The correlation coefficient (r) for regression analysis of the relation between the postoperative Pao 2/Fio 2 ratio and the postoperative (a/a)Po 2 ratio was 0.99 in the DM group (P〈0.01) and 0.88 in the non-DM group (P〈0.01). The r values of the relation between (a/a)Po 2 and (a-a)Po 2 were −0.68 (P〈0.00) and −0.84 (P〈0.01), while those for the respiratory index were −0.87 (P〈0.01), and −0.93 (P〈0.01), respectively. Thus, pulmonary oxygen transfer was compromised before and after CABG in the DM group compared to the non-DM group. Moreover, the Pao 2/Fio 2, being the simplest pulmonary gas exchange index to calculate, was a reliable substitute for the (a/a)Po 2 ratio during the early postoperative management of CABG patients.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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