Influence of cholinergic circuitries in generation of high-frequency somatosensory evoked potentials.

OBJECTIVE: High-frequency oscillations (HFOs) evoked by upper limb stimulation reflect highly synchronised spikes generated in the somatosensory human system. Since acetylcholine produces differential modulation in subgroups of neurons, we would determine whether cholinergic drive influences HFOs. METHODS: We recorded somatosensory evoked potentials (SEPs) from 31 scalp electrodes in 7 healthy volunteers, before and after single administration of rivastigmine, an inhibitor of central acetylcholinesterase. Right median nerve SEPs have been analysed after digital narrow bandpass filtering (500-700 Hz). Raw data were further submitted to Brain Electrical Source analysis (BESA) to evaluate the respective contribution of lemniscal, thalamic and cortical sources. Lastly, we analysed by Fast Fourier transform spectral changes after drug administration in the 10-30 ms latency range. RESULTS: Rivastigmine administration caused a significant increase of HFOs in the 18-28 ms latency range. Wavelets occurring before the onset latency of the conventional N20 SEP did not show any significant change. A similar increase concerned the strength of cortical dipolar sources in our BESA model. Lastly, we found a significant power increase of the frequency peak at about 600 Hz in P3-F3 traces after drug intake. CONCLUSIONS: Our findings demonstrate that the cortical component of HFOs is significantly enhanced by cholinergic activation. Pyramidal chattering cells, which are capable to discharge high-frequency bursts, are mainly modulated by cholinergic inputs; by contrast, acetylcholine does not modify the firing rate of fast-spiking GABAergic interneurons. We thus discuss the hypothesis that cortical HFOs are mainly generated by specialised pyramidal cells.     

Radionuclide evaluation of ventricular function at rest and during exercise in double inlet ventricle

We studied ventricular volumes and ejection fraction by radionuclide angiography (equilibrium technique) in 15 patients (aged 3-48 years) with double inlet ventricle not yet submitted to corrective surgery. The end-diastolic volume (measured in nine cases) ranged from 108 to 219 ml/m2 (156 +/- 32), being lower than the normal theoretical value (right plus left ventricle) in six cases. Ejection fraction ranged from 30 to 77% (56.4 +/- 13). The value was significantly higher in the subgroup of 10 patients with a dominant left ventricle as compared to the five cases with dominant right or indeterminate ventricular morphology (63.2 +/- 8.3 versus 42.8 +/- 9, P less than 0.01). In seven of the 15 patients, measurements were obtained both at rest and during dynamic exercise in the semi-upright position. The end-diastolic and end-systolic volumes, stroke volume, ejection fraction underwent a slight non-significant reduction (from 158 +/- 29 to 147 +/- 24 ml/m2, from 58 +/- 16 to 56 +/- 24 ml/m2, from 100 +/- 27 to 90 +/- 24 ml/m2, from 64% +/- 9 to 61% +/- 13). During exercise, ventricular volumes mostly behaved as follows: slight reduction of end-systolic volume, decrease of end-diastolic volume, no increase (no change or decrease) of ejection fraction.(ABSTRACT TRUNCATED AT 250 WORDS)     

Preoperative Carcinoembryonic Antigen and Prognosis of Colorectal Cancer. An Independent Prognostic Factor Still Reliable

To evaluate whether, in a sample of patients radically treated for colorectal carcinoma, the preoperative determination of the carcinoembryonic antigen (p-CEA) may have a prognostic value and constitute an independent risk factor in relation to disease-free survival. The preoperative CEA seems to be related both to the staging of colorectal neoplasia and to the patient''s prognosis, although this—to date—has not been conclusively demonstrated and is still a matter of intense debate in the scientific community. This is a retrospective analysis of prospectively collected data. A total of 395 patients were radically treated for colorectal carcinoma. The preoperative CEA was statistically compared with the 2010 American Joint Committee on Cancer (AJCC) staging, the T and N parameters, and grading. All parameters recorded in our database were tested for an association with disease-free survival (DFS). Only factors significantly associated (P < 0.05) with the DFS were used to build multivariate stepwise forward logistic regression models to establish their independent predictors. A statistically significant relationship was found between p-CEA and tumor staging (P < 0.001), T (P < 0.001) and N parameters (P = 0.006). In a multivariate analysis, the independent prognostic factors found were: p-CEA, stages N1 and N2 according to AJCC, and G3 grading (grade). A statistically significant difference (P < 0.001) was evident between the DFS of patients with normal and high p-CEA levels. Preoperative CEA makes a pre-operative selection possible of those patients for whom it is likely to be able to predict a more advanced staging.Key words: Colorectal carcinoma, Preoperative carcinoembryonic antigen, Disease-free survival, Independent prognostic factorIn the world today, more than 1 million cases of patients with colorectal neoplasia are identified each year. Forty percent of these will have a poor prognosis for which targeted therapeutic strategies could most likely be more effective.^1–3 For this reason, finding prognostic factors that are early, reliable, and related to the extent of the tumor is of the utmost importance. Among these, the most that are considered even to this day are T and N parameters.^1,2,4,5 Less relied upon, however, is the M parameter, which is often understaged due to inadequate pretreatment diagnostic methods.⁶ However, these parameters, which are available to us only after surgery, do not represent the gold standard. In fact, the prognosis of patients with the same staging is often various and that the need to continually implement ever-changing variables in an already excessively fragmented staging is still present.^2,4,7–9Recently, in light of these needs, great attention has been paid to the study of molecular and genetic markers. At present, these markers still have not found a regular application due to the complexity of their determination, the difficulty of standardization and, last but not least, the low cost-benefit ratio.^1,3,4,9,10With this in mind, in our opinion, the carcinoembryonic antigen (CEA) maintains its position, as for over 30 years it has continued to be the most widely used marker¹¹ and whose validity, with regard to colorectal follow-up, has been sanctioned by leading organizations such as the American Society of Clinical Oncology (ASCO)¹² and the European Group on Tumor Markers.¹³ Moreover, as Herrera¹⁴ and Wanebo¹⁵ had already reported by the end of the ‘70s, the preoperative determination of the CEA (p-CEA) seems to be related both to the staging of colorectal neoplasia and to the patient''s prognosis. However, to date, none of this has been conclusively demonstrated and is still a matter of intense debate both in prestigious scientific journals^{4,7,11,16–21} as well as in different guidelines.²²The American Society of Clinical Oncology itself, if on the one hand suggests using the determination of the CEA in the preoperative staging thus justifying a worse prognosis when increased,¹² on the other, does not validate using the p-CEA in the determination of an adjuvant or neo-adjuvant therapeutic strategy.²³Regarding this issue, we believe it still pertinent to evaluate whether in a sample of patients radically treated for colorectal carcinoma, the determination of the p-CEA may have a prognostic value and constitute an independent risk factor in relation to disease-free survival (DFS).     

Ontogeny of mitogen responsive lymphocytes in the bovine fetus

Bovine fetal lymphocytes were examined for their ability to respond to the mitogens phytohemagglutinin (PHA), Concanavalin A (ConA) and pokeweed mitogen (PWM) in the lymphocyte blastogenesis test (LBT). PHA-, Con A- and PWM-responsive lymphocytes appeared simultaneously at 75-80 days of gestation. The response increased with age of the fetus until, by 120 days of gestation, the response to PHA, Con A and PWM of many fetuses was in the range of values obtained with lymphocytes from normal adult cattle.     

Cranial neuropathy in systemic malignancy in a VA population

We studied 30 men with cranial neuropathy (CN) and systemic malignancy to determine the etiology and prognosis of CN. The most common malignancy was prostate (33%), followed by lung (27%). The etiology of CN was metastatic in 25 (83%) and nonmetastatic in 5 (17%). Only 6 patients improved: 3 metastatic and 3 nonmetastatic. Although prognosis for recovery was better in the nonmetastatic group, there was no significant difference in survival between the metastatic and the nonmetastatic groups.     

The use of intraluminal prosthesis in the surgical management of aortic dissection

The treatment of acute aortic dissection requires expeditions and reproducible operations aimed at avoiding rupture of the dissection or its antegrade or retrograde progression. In 12 type A and 11 type B dissections the aorta was repaired using an intraluminal prosthesis to reduce the risk of hemorrhage and its related complications. Overall mortality rates were 33% in type A and 36% in type B patients, similar to that observed in patients operated with other techniques, but the incidence of intraoperative bleeding was possibly reduced and the cross-clamping time was significantly shorter. This method of repair is a sound alternative to conventional anastomotic suturing, particularly in clinically compromised patients and in the hands of surgeons on call, who may lack the experience of dealing with a particularly fragile aortic wall.