Rapid-bolus contrast-enhanced dynamic computed tomography in acute pancreatitis: a prospective study.

The purpose of this prospective study was to determine the clinicopathological significance of necrotic areas demonstrated by rapid-bolus contrast-enhanced computed tomography (CT) in patients with biochemically predicted severe pancreatitis. Although CT necrosis occurred significantly more frequently in patients with clinically severe (ten of 12) compared with mild (seven of 20) pancreatitis (P less than 0.025), seven of 17 (41 per cent) patients with CT necrosis developed clinically mild pancreatitis and six of ten (60 per cent) patients with clinically severe pancreatitis and CT necrosis recovered with conservative management. The site and extent of CT necrosis did not correlate with disease severity. Fine-needle aspiration cytology, operative and post-mortem findings and endoscopic retrograde cholangiopancreatography examinations all strongly suggested that CT necrosis represents true pancreatic necrosis. We conclude that the finding of CT necrosis is not in itself an indication for operative intervention, but that rapid-bolus contrast-enhanced dynamic CT greatly facilitates the planning and execution of surgical therapy.     

Standard versus Fiberoptic Pulmonary Artery Catheterization for Cardiac Surgery in the Department of Veterans Affairs: A Prospective, Observational, Multicenter Analysis

Background: Controversy exists regarding the utility of continuous monitoring of mixed venous oxygen saturation (S vo2) during cardiac surgery. During a multicenter, prospective, observational study in the Department of Veterans Affairs (Cooperative Study #5), frequency of use of standard pulmonary artery catheterization (PAC) and S vo2-PAC was recorded. Here the authors relate these data to clinical outcomes.

Methods: Logistic and Cox regression models evaluating the association of PAC type with mortality, one or more postoperative complications, cardiac complications, time to extubation, and intensive care unit length of stay were constructed. The number of thermodilution cardiac outputs and arterial blood gas analyses performed in the first 24 h postoperatively were compared.

Results: Data from 3,265 patients undergoing myocardial revascularization (81.7%) or valve replacement-repair (18.3%) were considered. S vo2-PAC was used in 49% and PAC in 51% of patients. In the 14 hospitals, S vo2-PAC was used in all patients in four, in some patients in four, and never in six. No association of S vo2-PAC use with outcome were observed aside from unexplained hospital level effects. A small but statistically significant reduction in the number of arterial blood gas analyses (8 +/- 3 vs. 10 +/- 4, P < 0.0001, S vo2-PAC vs. PAC, respectively) and thermodilution cardiac outputs (14 +/- 8 vs. 15 +/- 9, P < 0.0001, S vo2-PAC vs. PAC, respectively) was observed with use of S vo2-PAC.     

The Effects of Combined Intravenous and Inhaled Steroids (Beclomethasone Dipropionate) for the Emergency Treatment of Acute Asthma

Objective : To compare the efficacy of high-dose inhaled steroids in conjunction with IV steroids with that of IV steroids alone in the emergency treatment for acute asthma.
Methods : A double-blind, placebo-controlled, randomized trial was conducted on 60 ED patients presenting with acute asthma. All patients received nebulized salbutamol, and IV methylprednisolone, 80 mg at baseline and 40 mg at 6 hours. In addition to the above therapy, the experimental group received beclomethasone dipropionate (BDP) 7 mg over 8 hours via a metered-dose inhaler (MDI) attached to a holding chamber, while the control group received a placebo administered in the same fashion. Patients were treated on the protocol for 12 hours with the primary outcome measure being the change in % predicted FEV₁.
Results : Of 60 patients, 30 were randomized to BDP (age: 42 ± 16 years; FEV₁: 0.97 ± 0.42 L) and 30 were randomized to placebo (age: 37 ± 18 years; FEV₁: 0.98 ± 0.35 L). Spirometry and dyspnea measured by the Borg Scale improved significantly in both groups compared with baseline (p < 0.001). Changes in spirometry measures, dyspnea, and vital signs did not differ between treatment groups over the 12 hours of study (p > 0.05).
Conclusion : Inhaled BDP added to the standard regimen of IV methylprednisolone, and β-agonist did not further improve flow rates or dyspnea scores measured for up to 12 hours after presentation to the ED.     

An inhibitory effect of veratridine during tetanic stimulation of the rat diaphragm

The membrane ‘labilizer’ veratridine (3.7 ± 10^-6 m) which potentiates the contractions at twitch (0.1 Hz) stimulation due to multiple discharges, inhibited the tetanic contractions (50 Hz in 10 s) and the simultaneously recorded electromyogram in a use-dependent way, leading to fading of tetanic tension. The effect was equal during indirect and direct stimulation, and could therefore be localized to the excitable sarcolemma. This was confirmed by intracellular recording of action potentials, showing a marked veratridine-induced fallout of action potentials during continuous 50 Hz stimulation, whereas endplate potentials were unaffected. Accordingly, veratridine probably caused a use-dependent inhibition of the Na⁺ channels of the excitable sarcolemma. The tetanic fade was unaffected by K⁺ depolarization, increased by hyperpolarization in K⁺-free solution, and decreased by high Ca²⁺. All these changes of the ionic concentrations inhibited the twitch potentiating effect of veratridine. Since hyperpolarization and increasing the electric field in the membrane with high Ca^,+ had opposite effects on the tetanic fade, the field change was probably not the cause of the antagonism in high Ca²⁺. Instead, a membrane stabilizing effect of high Ca²⁺ is suggested, since the neutral local anaesthetic benzocaine (1.5 ± 10^-4 m), which is also a membrane stabilizing drug, had the same effects as high Ca²⁺ on the veratridine-induced tetanic fade. The effect of veratrine during tetanic stimulation was partly reversible upon washing. The reversibility was enhanced by high Ca²⁺ or benzocaine.     

Hundreds of neurons in the Aplysia abdominal ganglion are active during the gill-withdrawal reflex

A combination of optical and electrode recording methods was used to obtain an overview of the neuron activity in the Aplysia abdominal ganglion in response to a light touch to the siphon skin. Spike activity was detected in up to 150 different neurons. Habituation and sensitization of the gill-withdrawal reflex was accompanied by large changes in the number of activated neurons. It is likely that these recordings are incomplete; the actual number of activated neurons is estimated to be about 300 in the acutely sensitized preparation. While we presume that not all 300 of these neurons are involved in the gill-withdrawal reflex, the number of neurons is so large that it may be difficult to determine the role of each activated neuron with presently available experimental tools.