Scalp electrical recording during paralysis: quantitative evidence that EEG frequencies above 20 Hz are contaminated by EMG.

OBJECTIVE: To identify the possible contribution of electromyogram (EMG) to scalp electroencephalogram (EEG) rhythms at rest and induced or evoked by cognitive tasks. METHODS: Scalp EEG recordings were made on two subjects in presence and absence of complete neuromuscular blockade, sparing the dominant arm. The subjects undertook cognitive tasks in both states to allow direct comparison of electrical recordings. RESULTS: EEG rhythms in the paralysed state differed significantly compared with the unparalysed state, with 10- to 200-fold differences in the power of frequencies above 20 Hz during paralysis. CONCLUSIONS: Most of the scalp EEG recording above 20 Hz is of EMG origin. Previous studies measuring gamma EEG need to be re-evaluated. SIGNIFICANCE: This has a significant impact on measurements of gamma rhythms from the scalp EEG in unparalysed humans. It is to be hoped that signal separation methods will be able to rectify this situation.     

Right Hepatic Lobectomy Using the Staple Technique in 101 Patients

Background Application of linear stapling devices for extrahepatic vascular control in liver surgery has been well-established. However, the technique for use of stapling devices in hepatic parenchymal transection is not well defined. Purpose To describe the safety and efficacy of our technique for use of vascular stapling devices in hepatic parenchymal transection during open right hepatic lobectomy is the purpose of this study. Methodology We reviewed our experience with 101 consecutive open right hepatic lobectomies performed by a single surgeon between January 2003 and July 2006, in which vascular staplers were utilized for the parenchymal transection phase. Results Of the 101 patients who underwent resection, 53 (52%) were female. The mean age was 58 years. Malignant disease was the indication for resection in the majority of patients (88%). Of those with cancer, 78% (69 of 89) had metastatic colorectal cancer, 6% (5 of 89) had metastatic neuroendocrine tumor, 4% (4 of 89) had hepatocellular carcinoma, 4% (4 of 89) had cholangiocarcinoma, and the remaining 8% were other metastatic cancers. Twelve patients (12%) underwent resection for hepatic adenoma or symptomatic benign disease (FNH or hemangioma). Forty-eight patients (48%) underwent a major ancillary procedure at the time of hepatic resection. Thirty-nine patients (39%) had a nonanatomic wedge resection of a left lobe lesion, 27 patients (27%) had one or more lesions treated with radiofrequency ablation (RFA), and 6 patients (6%) were treated with a synchronous bowel resection. The median total operative time was 336 min (range 155–620 min). A Pringle maneuver for temporary vascular inflow occlusion was utilized in all cases, with a median time of 9 min (range 4–17 min). Ten patients (10%) required blood transfusion during surgery or in the postoperative period. The maximum transfusion was 2 U of packed red blood cells (PRBC) in seven patients and 1 U of PRBC in three patients. The mean nadir postoperative hematocrit was 28.2. All patients with malignant disease had tumor-free margins at the completion of the procedure. The average hospital length of stay was 6.0 days. One patient (1%) developed a clinically significant bile leak requiring a postoperative endoscopic retrograde cholangiography (ERCP). No patient required reoperation. The 30 and 60-day postoperative survival was 100%. Conclusion These findings indicate that application of vascular stapling devices for parenchymal transection in major hepatic resection is a safe technique, with low transfusion requirements and minimal postoperative bile leak. The technique allows for rapid transection of the entire right hepatic lobe in under 10 min. Short video clips of the technique will be demonstrated. Presented at the 2007 American Hepato–Pancreato–Biliary Association, Las Vegas, Nevada, April 19–22, 2007 (oral presentation/video presentation).     

Fetal beta-endorphin levels in response to reductions in uterine blood flow

Fetal beta-endorphin release has been associated with fetal hypoxia. The purpose of this study was to assess the degree of uterine blood flow reduction needed to elicit fetal beta-endorphin release in the sheep since there is a large reserve of oxygen supply to the fetus. Uterine blood flow was reduced by 26 +/- 2, 46 +/- 3 and 66 +/- 2%, producing fetal oxygen content concentrations of 5.7 +/- 0.6, 4.4 +/- 0.7 and 2.6 +/- 0.3 ml/dl, respectively. Although fetal oxygen concentrations were significantly decreased in the groups with a reduction in uterine blood flow of 46 and 66%, beta-endorphin was elevated only in the latter group. It is speculated that fetal beta-endorphin is released at a level of hypoxia which leads to a decrease in fetal oxygen consumption. A reduction in uterine blood flow of 66% appears to produce a stressful environment for the fetus as measured by fetal plasma beta-endorphin levels.     

Colony-stimulating factors for chemotherapy-induced febrile neutropenia: a meta-analysis of randomized controlled trials.

PURPOSE: Current treatment for febrile neutropenia (FN) includes hospitalization for evaluation, empiric broad-spectrum antibiotics, and other supportive care. Clinical trials have reported conflicting results when studying whether the colony-stimulating factors (CSFs) improve outcomes in patients with FN. This Cochrane Collaboration review was undertaken to further evaluate the safety and efficacy of the CSFs in patients with FN. METHODS: An exhaustive literature search was undertaken including major electronic databases (CANCERLIT, EMBASE, LILACS, MEDLINE, SCI, and the Cochrane Controlled Trials Register). All randomized controlled trials that compare CSFs plus antibiotics versus antibiotics alone for the treatment of established FN in adults and children were sought. A meta-analysis of the selected studies was performed. RESULTS: More than 8,000 references were screened, with 13 studies meeting eligibility criteria for inclusion. The overall mortality was not influenced significantly by the use of CSF (odds ratio [OR] = 0.68; 95% CI, 0.43 to 1.08; P = .1). A marginally significant result was obtained for the use of CSF in reducing infection-related mortality (OR = 0.51; 95% CI, 0.26 to 1.00; P = .05). Patients treated with CSFs had a shorter length of hospitalization (hazard ratio [HR] = 0.63; 95% CI, 0.49 to 0.82; P = .0006) and a shorter time to neutrophil recovery (HR = 0.32; 95% CI, 0.23 to 0.46; P < .00001). CONCLUSION: The use of the CSFs in patients with established FN caused by cancer chemotherapy reduces the amount of time spent in hospital and the neutrophil recovery period. The possible influence of the CSFs on infection-related mortality requires further investigation.     

Regulation of Basal and Nursing-Induced Secretion of Growth Hormone in the Neonatal Rat: The Involvement of Serotonergic, Muscarinic Cholinergic, Alpha2-Adrenergic, Somatostatin and Growth Hormone-Releasing Hormone Systems

Various neural factors are involved in the suckling-induced increase in serum growth hormone (GH) levels in neonatal rats, and, in the present study the serotonergic, cholinergic, somatostatin and GH-releasing hormone (GHRH) systems were investigated. The serotonin (5-HT) precursor 5-hydroxy-L-tryptophan (5-HTP) and the 5-HT receptor agonist quipazine maleate stimulated serum GH levels in 2-day-old rat pups separated from their mothers for 6 h. The increase in serum GH during suckling was further elevated by 5-HTP. The 5-HT antagonist cyproheptadine decreased serum GH levels in separated 2-day-old pups, and although it reduced the amplitude of the suckling-induced increase in serum GH concentration, it did not alter the increase in serum GH on a percentage basis. The effect of the cholinergic muscarinic antagonist atropine sulfate (ATR) was similar to that of cyproheptadine. Moreover, in separated pups, ATR prevented the increase in serum GH induced by 5-HTP. In contrast with 2-day-old pups, ATR completely eliminated the suckling-induced release of GH in 10-day-old rats. However, ATR failed to prevent GH release induced by the α₂-adrenergic agonist clonidine HCI in 10-day-old male pups. While thyrotropin-releasing hormone increased serum GH levels, rat GHRH failed to alter serum GH levels either in separated or in suckled 2-day-old rat pups. Immunoneutralization for rat GHRH eliminated the increase in serum GH induced by clonidine HCI in 10-day-old pups, but (on a percentage basis) failed to prevent the GH-increasing effect of suckling in 2-day-old pups. While somatostatin failed to significantly decrease serum GH in separated 2-day-old pups, it effectively decreased serum GH levels in 2-day-old pups which were suckled. Cysteamine, which depletes hypothalamic somatostatin, increased serum GH in separated 2-day-old pups, and further increased the suckling-induced levels of serum GH. Cysteamine partially prevented the GH-decreasing effect of ATR. The present findings suggest that 1) the serotonergic and cholinergic systems are involved in the regulation of GH secretion as early as day 2 postpartum; 2) the serotonergic and cholinergic systems modulate the basal, and do not modulate the suckling-induced levels of serum GH; 3) the serotonergic system may exert its stimulatory influence on GH secretion only in the presence of a functional muscarinic cholinergic system; 4) the cholinergic system, at least in part, stimulates GH secretion via a cysteamine-sensitive system (probably by inhibiting somatostatin); 5) the cholinergic system is not functionally coupled with the α₂-adrenergic system, which stimulates GH secretion via rat GHRH; 6) since in 10-day-old pups clonidine HCI was effective only in males, while suckling was effective in both sexes, the α₂-adrenergic system is not involved in the suckling-induced increase of serum GH; and finally 7) neither somatostatin nor rat GHRH seem to be involved in the suckling-induced changes in serum GH. The findings are consistent with the hypothesis that the high circulating GH levels in the neonatal rat are due to alternative GH-releasing factors, perhaps thyrotropin-releasing hormone or γ-aminobutyric acid. The neurohumoral mediator of the suckling-induced GH release in neonatal rats remains to be identified.     

Reduction of Immunosuppression for Transplant-Associated Skin Cancer: Rationale and Evidence of Efficacy

BACKGROUND: Solid organ transplant recipients may develop numerous or life-threatening skin cancers. In addition to aggressive standard treatment of skin cancer, reduction of immunosuppression has been considered an adjuvant therapeutic strategy, albeit without direct proof of efficacy. OBJECTIVE: To review the rationale for and evidence supporting the efficacy of reduction of immunosuppression for severe skin cancer in transplant recipients. METHODS: Review of the literature regarding direct and indirect evidence on reduction of immunosuppression for transplant-associated skin cancer. RESULTS: Although there are no randomized controlled trials of reduction of immunosuppression as a therapeutic intervention for transplant patients with skin cancer, multiple lines of evidence suggest that this strategy may be an effective adjuvant therapy. A randomized trial has demonstrated a lower incidence of skin cancer in transplant recipients after reduction of immunosuppression, albeit in a cohort not previously affected by skin cancer. Case series of reduction or cessation of immunosuppression demonstrate a lower incidence of skin cancer or improved outcomes of preexisting skin cancer. Lower overall immunosuppression is associated with a lower incidence of skin cancer. Multiple cancers affecting the skin have been shown to regress with reduction of immunosuppression. CONCLUSIONS: Reduction of immunosuppression may be an effective adjuvant therapeutic strategy when confronting severe transplant-associated skin cancer. The risks of reduction of immunosuppression must be better defined, and randomized trials of this strategy are necessary.     

药物动力学入门(三)

重复给药许多药物不仅投药一次。病人在接受药物治疗时,通常是经多次的药物应用。这样每一剂量给予的次数和多少则称为给药方案。通过给药方案的调整,则可以显著地改变药物治疗的效果。口服给药如果口次剂量每次给药的间隔相当长,则由每一次剂量所给的药物已几乎完全消除,所以这些分次给药的行为相互将无何影响,如图33所示。