Normovolaemic haemodilution and hyperoxia have no effect on fractal dimension of regional myocardial perfusion in dogs

Hypervolaemic haemodilution makes myocardial perfusion more homogenous as reflected by reduced fractal dimension of regional myocardial perfusion. The clinically more commonly performed acute normovolaemic haemodilution, however, has not yet been studied in this respect. Hyperoxic ventilation with 100% oxygen is used in conjunction with haemodilution to compensate for low oxygen content by increasing physically dissolved oxygen in plasma. Since hyperoxia is known to cause disturbance in microcirculatory regulation we studied the effects of acute normovolaemic haemodilution to haematocrit (hct) 20 ± 1% and hyperoxia on regional myocardial perfusion heterogeneity in 22 anaesthetized dogs using fractal and correlation analysis. Regional myocardial perfusion was assessed with radioactive microspheres. The results of the study were that heart rate, blood volume and arterial pressure were unchanged during haemodilution. Cardiac index was 3.6 ± 0.7 L min^?1 m^?2 before and 4.6 ± 0.7 L min^?1 m^?2 after haemodilution (P < 0.05). Fractal dimension (D) of regional myocardial perfusion was 1.17 ± 0.10 at baseline. Neither haemodilution (D = 1.19 ± 0.10) nor hyperoxia (D = 1.17 ± 0.10) altered fractal properties of regional myocardial perfusion. Spatial correlation of blood flow to adjacent tissue samples before haemodilution was 0.58 ± 0.15. Haemodilution and hyperoxia did not significantly influence spatial correlation (0.57 ± 0.12 vs. 0.60 ± 0.09; ns). We conclude that neither acute normovolaemic haemodilution nor haemodilution in combination with hyperoxic ventilation alter physiological myocardial perfusion heterogeneity.     

Incidence of Atrial Fibrillation in Patients with Different Mode of Pacing. Long-term Follow-up

We evaluated the incidence of atrial fibrillation in 189 patients (92males, 97females, mean age 75 ± 12yrs, range 41–100yrs) with pacemaker, during a mean follow-up of 5.5yrs (range 1–24yrs). The indications for implant were: complete AV block (115pts), second degree Möbilz 2 AV block (51pts). bifascicular block (5pts). sick sinus syndrome (14pts), symptomatic bradycardia (4pts). The mode of stimulation considered were VVI (105pt), VVI rate responsive (21pts), single lead VDD (43pts), DDD (20pts). The occurrence of retrograde VA conduction in patients with VVI or VVI rate responsive pacing was also evaluated. Atrial fibrillation occurred in 40 pts (21%). The highest incidence was evidenced in patients with sick sinus syndrome (9pts, 64%), and in patients with VVI stimulation (28pts, 27%). On the contrary, the lowest incidence was found in single lead VDD stimulation (4pts, 9%). The patients with dual chamber pacing showed a relatively high incidence of the arrhythmia (5pts, 25%). Atrial fibrillation occurred in 9 out of 32 patients with retrograde VA conduction, and in 22 out of 94 patients without retrograde conduction (28% versus 23%, p=NS). In conclusion, it is confirmed that patients with sick sinus syndrome are at high risk for atrial fibrillation. Single lead VDD stimulation seems to be the better mode of pacing in preventing atrial fibrillation, while dual chamber pacing showed minor efficacy. The presence of retrograde VA conduction could not predict the occurrence of the arrhythmia.     

Modulation of all-trans retinoid acid pharmacokinetics in acute promyelocytic leukaemia by prolonged interferon-α therapy

Summary. Continuous treatment with all-trans retinoid acid (ATRA) induces accelerated drag catabolism which is considered responsible for acquired resistance to ATRA. We studied the effect of interferon-o:2a (IFN) on ATRA pharmacokinetics in two patients with acute promyelocytic leukaemia (APL) in complete remission maintained by alternating 15d of IFN and 15 d of ATRA. Day 15 ATRA levels obtained during IFN + ATRA treatment were significantly higher than those observed in patients maintained on ATRA alone. In one patient IFN was discontinued and day 15 ATRA levels decreased to those observed in patients scheduled for maintenance with ATRA alone. In our two patients IFN substantially reduced the induction of ATRA catabolism, indicating a potential role for IFN in modulating ATRA pharmacokinetics.     

Familial gastric cancer and Li–Fraumeni syndrome

CORSO G., PEDRAZZANI C., MARRELLI D., PINTO E. & ROVIELLO F. (2010) European Journal of Cancer Care 19 , 377–381
Familial gastric cancer and Li–Fraumeni syndrome Gastric cancer occurs in some familial diseases with inherited cancer predisposition. Genetic factors have been correlated with the hereditary diffuse gastric cancer and other familial gastric cancer conditions as hereditary non‐polyposis colorectal cancer and Li–Fraumeni syndrome. The present study was aimed at searching for germ line mutations of TP53 gene in familial gastric cancer with cluster for Li–Fraumeni syndrome or Li–Fraumeni‐like syndrome. Twenty‐three pedigrees with characteristics for Li–Fraumeni‐like syndrome were identified. DNA of the proband was sequenced using polymerase chain reaction/single‐strand conformation polymorphism. Among these 23 cases, no germ line mutation of TP53 was identified, while two single‐nucleotide polymorphisms were identified in four patients. In our area, in which a high rate of familial aggregation was demonstrated, the lack of germ line mutation of TP53 together with the infrequency of mutation of E‐cadherin gene seem to limit the role of genetic predisposition in the development of gastric cancer.