Systemic coronary surgery in the beating heart. Experience in 250 cases

OBJECT: To report our recent experience with off-pump coronary artery revascularization in multi-vessel disease. METHODS: Between October 1996 and August 1998, 250 off-pump (OP) procedures were completed at the Montreal Heart Institute, representing more than 90% of all procedures done during the same time frame (97% for 1998). These patients have been compared to 1870 patients operated upon under cardiopulmonary bypass during the years 1995-1996 (CPB). RESULTS: Mean age, sexe distribution, and preoperative risk factors were comparable for both groups. On average 2.89 +/- 0.8 and 2.84 +/- 0.6 grafts/patient were completed in OP and CPB groups respectively. A majority (70%) of patients had either a triple or quadruple bypass. Coronary anastomoses were achieved with myocardial mechanical stabilization and heart "verticalization". Ischemic time was shorter in the OP group (29.8 +/- 0.9 vs 45 +/- 0.4 min, p < 0.05). Similarly, need for transfusion was significantly less (OP: 34 vs CPB: 66%, p < 0.005). Use of postoperative intra-aortic counterpulsation as well as the raise of CK-MB were lesser in the OP group. Operative mortality (OP: 1.6%, vs CPB: 2%, p = ns) and perioperative myocardial infarction rate (OP: 3.6% vs CPB: 4.2) were comparable for both groups. CONCLUSION: Off-pump complete coronary artery revascularization is an acceptable alternative to conventional surgery in a majority of patients with good results given progressive experience, rigorous technique, and adequate coronary artery stabilization.     

Mechanisms of protection afforded by cyclooxygenase inhibitors to endothelial function against ischemic injury in rat isolated hearts.

The aim of this study was to assess whether cyclooxygenase (COX) inhibitors protect the endothelial function against the deleterious effect of ischemia and reperfusion. Isolated rat hearts perfused under constant-flow conditions were exposed to 30 min of partial ischemia (flow, 1 ml/min) followed by 20 min of reperfusion, after which coronaries were precontracted with U-46619, and the response to the endothelium-dependent vasodilator, serotonin (5-HT), was compared with that of the endothelium-independent vasodilator, sodium nitroprusside (SNP). In untreated hearts, ischemia diminished selectively 5-HT-induced vasodilation, compared with sham hearts (without ischemia). The vasodilation to SNP was unaffected in all groups. Pretreatment with 6-MNA, 30 microM, a COX-2 inhibitor with some activity on COX 1, diclofenac, 1 microM (COX-1 and -2), or 1-(7-carboxyheptyl) imidazole, 10 microM [thromboxane (TX) synthase inhibitor] but not indomethacin, 10 microM (COX-1 inhibitor) preserved the vasodilation induced by 5-HT after ischemia. Enzyme immunoassays indicated that all COX inhibitors decreased the concentration of TXB2 and 6-keto-PGF1alpha [stable metabolites of TXA2 and prostacyclin (PGI2), respectively] in coronary effluent during ischemia. Furthermore, indomethacin was the only one to abolish the concentration of PGE2 during ischemia and early reperfusion. No clear trend on ventricular postischemic recovery could be observed between treated and untreated groups under our experimental protocols. These data suggest that, under our conditions, 6-MNA, diclofenac, and 1-7-CHI, but not indomethacin, protect the endothelial function via a reduction in TX concentration. Disparities between COX inhibitors may be due to the complete abolition of PGE2 concentration during ischemia and reperfusion in the indomethacin group.     

Leucoéncephalopathie multifocale progressive

Summary A young woman presented a mixed congenital and familial immunodeficiency syndrome consisting in an absence of IgA and lowered levels of IgG and IgM, with a defect in cellular immunity. She had a mild malabsorption syndrome with slight alterations of the jejunal mucosa. Non-caseating tuberculoid granulomata were found in skin lesions, in lymph nodes and in the spleen. At age 27 the patient died of a neurological disease of 4 months duration. Autopsy revealed a very widespread demyelinating process involving mainly the right cerebellar hemisphere but also most of the pons and left cerebellum, with the typical morphologic characters of PML. In the hemispheres lesions were limited to microscopical microglial nodules with discrete demyelination. A review of 86 published cases of PML revealed 9 other cases in which lesions showed a strong predilection for the subtentorial territories. This sampling allows for the assumption that some 11% of the cases of PML have this particular lesion distribution. Other pertinent features of this case are briefly discussed.

     

Absolute fat mass, percent body fat, and body-fat distribution: which is the real determinant of blood pressure and serum glucose?

Associations of body mass index (BMI), absolute fat mass, percent body fat, and regional fat distribution with concentrations of fasting blood glucose and blood pressure were examined cross-sectionally in 1551 men and women aged 15-79 y from two study centers. Measurements included height, weight, multiple skinfold thicknesses, body density by underwater weighing, and waist and hip girths. Three principal findings emerged: 1) Absolute overall body mass and fat mass were stronger predictors of blood pressure and blood glucose than were relative fat mass, after age, height, and current cigarette-smoking status were adjusted for; 2) when diastolic blood pressure and serum glucose were used as the external validity criteria, densitometry was not a "gold standard" for body composition associated with risk for increased blood pressure and serum glucose; and 3) BMI was as good a predictor of blood pressure and glucose as was any other measure of body fat in nearly all analyses.     

Pathologic study of Morton's neuroma

The clinical syndrome of Morton's neuroma [correction of nephroma] was described over a century ago, but its etiopathology remains unknown. Recent studies suggest that it may be induced by compression neuropathy. Histologic changes in digital nerves resected for therapeutic purposes were compared with histologic findings of digital nerves sampled at autopsy of asymptomatic subjects. Results show that approximately one-third of resected "diseased" digital nerves were histologically normal. The authors question the therapeutic approach, which consists of resecting the nerves.     

Intraoperative cranial nerve monitoring during posterior skull base surgery

Intraoperative monitoring of neurophysiologic function is rapidly evolving as an important adjunct during skull base surgery to reduce the incidence of neurologic deficit. Facial nerve monitoring is an excellent model, since electrical and mechanical evoked potentials can be directly presented to the surgeon in real-time through an acoustic loudspeaker display. The lower cranial nerves may also be monitored using similar electromyographic techniques. Auditory system monitoring is more difficult due to the low amplitude response that requires averaging and filtering to extract the evoked potential. In conjunction with auditory monitoring, improved hearing preservation may be further enhanced by concomitant facial nerve monitoring, since the surgeon is alerted to traumatic manipulations that may affect both facial and cochlear nerves. Techniques and interpretative issues are presented to maximize the efficacy and safety of cranial nerve monitoring.     

Thalamic evoked potentials to somatosensory stimulation in man.

Thalamic somatosensory evoked potentials (ThSEPs) were recorded by averaging technique from various thalamic structures during 59 stereotactic operations. From 372 records, response patterns and latency characteristics were analysed in relation to the intrathalamic localization. The findings can be summarized as follows. In N. ventro-caudalis (VC) and ventro caudalis parvocellularis (Vcpc) ThSEPs showed the most definite (and exclusively contralateral) responses characterized by a single positive (P1) deflection. The latency was shortest in VC (mean value, 17.5 msec) and in Vcpc (15.6 msec). Responses from N. centrum medianum (CM), parafascicularis (Pf) and limitans (Lim) were composed of early P1-N1 and of later P2-N2 components. The P1 latency was relatively consistent, with a mean value of 28.2 msec. Pulvinar responses showed a pattern similar to CM, with a mean P1 latency at 30.5 msec. Responses of N. dorsalis medialis (DM) were small, variable and longest, with a mean P1 latency of 54.2 msec. To ipsilateral stimulation, CM, Pul, DM and N. ventro-lateralis (VL) showed comparable wave forms. The possible role of the CM-Pf-Lim complex and of Pulvinar in the "extra-lemniscal" sensory system was considered. The usefulness of ThSEP recording to identify electrode locations in the thalamus is thus confirmed.     

A toxicokinetic model of malathion and its metabolites as a tool to assess human exposure and risk through measurements of urinary biomarkers.

A toxicokinetic model is proposed to predict the time evolution of malathion and its metabolites, mono- and dicarboxylic acids (MCA, DCA) and phosphoric derivatives (dimethyl dithiophosphate [DMDTP], dimethyl thiophosphate [DMTP], and dimethyl phosphate [DMP]) in the human body and excreta, under a variety of exposure routes and scenarios. The biological determinants of the kinetics were established from published data on the in vivo time profiles of malathion and its metabolites in the blood and urine of human volunteers exposed by intravenous, oral, or dermal routes. In the model, body and excreta compartments were used to represent the time varying amounts of each of the following: malathion, MCA, DCA, DMDTP, DMTP, and DMP. The dynamic of intercompartment exchanges was described mathematically by a differential equation system that ensured conservation of mass at all times. The model parameters were determined by statistically adjusting the explicit solution of the differential equations to the experimental human data. Simulations provide a close approximation to kinetic data available in the published literature. When simulating a dermal exposure to malathion, the main route of entry for workers, the model predicts that it takes an average of 11.8 h to recover half of the absorbed dose of malathion eventually excreted in urine as metabolites, compared to 3.2 h following an intravenous injection and 4.0 h after oral administration. This shows that following a dermal exposure, the absorption rate governs the urinary excretion rate of malathion metabolites because the dermal absorption rate is much slower than biotransformation and renal clearance processes. The model served to establish biological reference values for malathion metabolites in urine since it allows links to be made between the absorbed dose of malathion and the time course of cumulative amounts of metabolites excreted in urine. From the no-observed-effect level (NOEL) of 0.61 micromol/kg/day derived from the data of Moeller and Rider (1962), the model predicts corresponding biological reference values for MCA, DCA, and phosphoric derivatives of 44, 13, and 62 nmol/kg, respectively, in 24-h urine samples. The latter were used to assess the health risk of workers exposed to malathion in botanical greenhouses, starting from urinary measurements of MCA and DCA metabolites.     

Ewing’s肉瘤细胞X-射线照射后TNF-α和TGF-β mRNA表达的研究

 目的　研究Ewing’s肉瘤细胞系 (RM 82 )X 射线外照射后肿瘤坏死因子 (TNF α)和转化生长因子 (TGF β)mRNA表达水平的变化 ,探讨X 射线诱导内源性TNF α和TGF β产生的可能性及意义。 方法　应用实时荧光RT PCR ,检测接受不同剂量X 线照射 (2Gy ,5Gy ,10Gy ,2 0Gy ,30Gy ,4 0Gy)和受照后不同时间 (1h ,3h ,6h ,12h ,2 4h ,4 8h ,72h)。TNF α和TGF βmRNA表达水平的变化。 结果　RM 82细胞TNF αmRNA表达水平较外照射前显著升高。一方面受照后TNF αmRNA表达逐渐升高 ,照射剂量达 4 0Gy时TNF αmRNA表达水平达高峰 ,为正常对照组的 10 8倍 ;另一方面 ,照射后 3h后TNF αmRNA表达逐渐升高 ,6h达高峰 ,为正常对照组的 18倍。相反 ,TGF βmRNA表达水平X 射线照射前后无显著变化。结论　Ewing’s肉瘤细胞系 (RM 82 )接受X 线照射后TNF αmRNA表达明显升高 ,且呈现时间、剂量依赖性。放射治疗可诱导Ewing’s肉瘤细胞系 (RM 82...     

Fat gram target to achieve high energy intake in cystic fibrosis

Higher fat and energy intakes confer a survival advantage in cystic fibrosis (CF). There is a need to develop effective nutrition programmes that ensure optimal energy intake in CF.

Methodology:

A cross-sectional measurement of clinical characteristics and energy and fat intakes in patients attending the CF outpatients clinic of the John Hunter Hospital, Newcastle was undertaken. Twenty-nine subjects, mean age 12 years (range 4.3–20.2), completed weighed food records to determine the contribution of fat to the percentage of the recommended energy intake obtained and to document use of pancreatic enzyme replacement therapy.

Results:

Diets with a high percentage of energy derived from fat did not guarantee that individuals with CF met their energy requirements. Subjects with total fat intakes of 100 g per day or greater, however, achieved in excess of 110% recommended daily intake (RDI) for energy. Up to 47% of subjects consumed more pancreatic enzyme replacement capsules than shown to give maximum effectiveness.

Conclusion:

Setting a 100 g daily fat target is a realistic way of ensuring high energy intakes in CF. Fat ready reckoners would identify the fat content of food and prescribe specific numbers of pancreatic enzyme replacement capsules to be consumed with each meal or food item.