Compact voltage and current stimulation buffer for high-density microelectrode arrays.

We report on a compact (0.02 mm(2) ) buffer for both voltage and current stimulation of electrogenic cells on a complementary metal-oxide semiconductor microelectrode array. In voltage mode, the circuit is a high-current class-AB voltage follower, based on a local common-mode feedback (LCMFB) amplifier. In current mode, the circuit is a current conveyor of type II, using the same LCMFB amplifier with cascode stages to increase the gain. The circuit shows good linearity in the 0.5-3.5 V input range and has extensively been used for stimulation of neuronal cultures.

Continuous infusion of vancomycin in methicillin-resistant staphylococcus infection.

OBJECTIVE: The aim of the study was to verify the therapeutic response of vancomycin in methicillin-resistant staphylococcus infection (MRSA/ MRCNS) administered according to two different methods (intermittent infusion vs. continuous infusion). METHOD: Experimental plan: retrospective study; study environment: university hospital, two intensive care units. Twenty-five critically ill patients submitted to antibiotic treatment with vancomycin for infection from MRSA/MRCNS were studied. The patients, who were classified according to SAPS II scores, were divided into two groups: group A (n = 14): dose of vancomycin of 0.5 g x 4/day and group B (n = 11): dose of 2 g/day of vancomycin administered in a continuous infusion. Before the antibiotic therapy was started (T1) and prior to its end (T2), the following parameters were evaluated: degree of impairment of the main organs and systems by means of sepsis-related organ failure assessment score (SOFA) and count of the white blood cells (WBC). The length of the hospital stay during intensive care was calculated for both groups (statistics: Student t test). RESULTS: No significant differences were found in the SAPS II scores and in the length of the hospital stay. In a comparison of the T1 and T2 results, we noted that patients of group A had no variations in the SOFA scores (4.84 +/- 2.48 vs. 4 +/- 3.9) and in the WBC mean values (12,415 +/- 5,099 vs. 12,841 +/- 6,864 cells/mm3). In contrast, in the patients of group B, we noted significant variations (p < 0.05) in the mean values of the SOFA scores (6.62 +/- 2.2 vs. 4.37 +/- 3.5) and in the mean values relative to the WBC count (17,242 +/- 12,842 vs. 10,757 +/- 3,610 cells/mm3). CONCLUSIONS: In critically ill patients suffering from MRSA/MRCNS infection, vancomycin administration in continuous infusions improved organ function and leukocyte response, but did not seem to modify the overall evolution of the disease.

Sensitive and rapid method for the simultaneous quantification of five antidepressants with their respective metabolites in plasma using high-performance liquid chromatography with diode-array detection.

A high-performance liquid chromatographic method with diode array detection (HPLC-DAD) has been developed for the simultaneous separation and quantification of imipramine, amitriptyline, maprotiline, fluoxetine, clomipramine and their respective metabolites using a 500-microl plasma sample and clovoxamine as the internal standard. The substances were eluted on a Symmetry C18 5-microm column (250x4.6 mm, I.D.). Full UV spectra from 200 to 450 nm were recorded on-line during the entire analysis and were automatically compared to spectra stored in a library. The quantification was performed at 226, 254, and 400 nm. Peak height ratios were linear over a concentration range of 10-3000 ng/ml: the correlation coefficient (r) was better than 0.998 for all substances at each wavelength. Acceptable coefficients of variation are demonstrated for both within-run and day-to-day assays. The method is simple, highly specific and currently being used for drug monitoring and toxicological studies in children and adult patients.

[Evaluation of the synergism between ketorolac and morphine in the treatment of postoperative pain]. / Valutazione del sinergismo tra ketorolac e morfina nel trattamento del dolore postoperatorio.

BACKGROUND: The aim of the study is to determine what concentration of ketorolac and morphine administered together i.v. achieve best synergic effect between NSAID antiinflammatory and opioids analgesic properties. DESIGN: Randomized comparative study was carried out on 180 patients, ASA II-IV, undergoing major general surgery, in an University Clinic. METHODS: Postoperative pain therapy by i.v. PCA: group 1 morphine 0.75 mg.ml + ketorolac 0.75 mg.ml; group 2 morphine 0.50 mg.ml + ketorolac 1.50 mg.ml; group 3 morphine 0.25 mg.ml + ketorolac 1.50 mg.ml; in saline solution. Initial bolus: 2 ml. Continuous infusion 1.5 ml.h. Demand bolus: 0.2 ml. Lockout time: 30 minutes. Evaluations included: pain intensity (T0, T3, T18); total amount of infused drugs (T18); number of valid demands and attempts (T18); amount of autoadministered analgesic drugs in percent of highest available amount (T18); side effects (T18); patient's judgment. DATA ANALYSIS: ANOVA and Student's "t"-test. RESULTS: A statistically significant reduction of pain intensity was found after 3 and 18 hours in the three groups, no differences were found among the groups. Group 2 required an amount of autoadministered drugs significantly lower than other groups. Rare side effects. Patient's judgment was generally positive. CONCLUSIONS: Results suggest a greater synergetic effect between morphine and ketorolac in concentrations used in group 2.

[Gabexate mesilate (FOY), a new synthetic protease inhibitor, in the treatment of shock. An Italian multicenter study]. / Il gabesato mesilato (FOY), nuovo antiproteasico sintetico, nel trattamento dello shock. Studio multicentrico italiano.

BACKGROUND: Circulatory shock has been accepted as a consequence of a chain of biochemical events beginning with production of proteases and ending with an uncontrolled generation of oxygen radicals. OBJECTIVE: To evaluate the efficacy of gabexate-mesilate (FOY) in circulatory shock in man. Gabexate-mesilate is a new wide-range synthetic protease inhibitor that also has antioxidant properties. DESIGN: Clinical multicenter study with open design that has been compared with some Japanese controlled studies performed using identical parameters and very similar protocols. EXPERIMENTS: 59 shocked patients were treated with FOY in 9 italian intensive therapy units. Circulatory shock was traumatic (n = 14), traumatic-hemorrhagic (n = 25), septic (n = 11) or of mixed type (n = 9). Evaluation of seriousness of shock on beginning of therapy and during the follow-up period was performed on the basis of the same "shock score" (Ogawa and Fujita, Jap J Surg 12:122, 1982) that was used in Japanese clinical studies on FOY in shock. 1.45 mg/kg/hour of FOY were injected i.v. during 48 hours. Conventional therapy was permitted but steroids and aprotinin were excluded. The follow-up period was 9 days. RESULTS: 8 patients died. The mean initial score of the survivors was 8.2; after 8 hours it was 5.0 and after 12 it was 4.0. No adverse reactions were reported. The above quoted survival was greater than that of Japanese studies although the initial score was quite the same. However these studies were controlled and demonstrated gabexate-mesilate to be significantly more active in shock therapy than placebo. They also demonstrated an activity of FOY greater than that of aprotinin when shock was associated to acute respiratory insufficiency and to coagulopathies. CONCLUSIONS: Gabexate mesilate might be useful in therapy of circulatory shock due to its wide-range inhibition of proteases and to its antioxidant properties.

Oxygen-derived free radicals in the pathogenesis of experimental shock.

Oxygen-derived free radicals are naturally produced in biological systems mostly in ischemia and hypoxia related conditions. Imbalance of physiological defenses against oxygen-derived free radicals causes cellular damage. In our laboratory the role of oxygen radicals in the pathogenesis of circulatory shock was studied by exploiting the scavenging action of the spin-trapping compound phenyl-butyl-nitrone (PBN) in experiments concerning: (1) survival after shock, (2) microcirculatory derangements in endotoxin shock, (3) fluidity modifications of cell membranes during shock, (4) exhalation of ethane as non-invasive marker of shock. In some experiments the steroid methylprednisolone was used. Results showed that administration of PBN and of the steroid (1) ensures survival after otherwise lethal shock as confirmed by decreased ethane exhalation, (2) prevents microcirculatory troubles, (3) maintains stability of cell membranes. These findings strongly support the role of oxygen-derived free radicals in the pathogenesis and pathophysiology of circulatory shock.

[Anesthesia for outpatient termination of pregnancy: a comparison of anesthetic techniques]. / Valutazione di quattro metodiche di anestesia nell'interruzione volontaria di gravidanza.

PIP: 60 outpatients who submitted to termination of pregnancy at less than 12 weeks gestation (legal abortion) were randomly anesthetized with fentanyl + thiopentone, ketamine + diazepam, thiopentone + halotane, or thiopentone + enflurane. Each patient breathed spontaneously 3 liters/minute of nitrous oxide. The psychomotor recovery time was evaluated by means of the Zazzo test of "deux barrages" and the matrix attentive test. The anesthesia time and the intra- and postoperative side effects were recorded too. There was a greater frequency of nausea, vomiting, headache, and postoperative restlessness in those patients anesthetized with ketamine + diazepam. This anesthetic mixture induced a longer psychomotor recovery time. On the other hand, in patients anesthetized with fentanyl + thipentone, the authors observed a need for intraoperative additional analgesia during dilatation of the cervix. On the contrary, either technique with the volatile anesthetic agents halothane or enflurane is satisfactory for outpatient termination of pregnancy. When compared with the total intravenous anesthetic technique, the use of enflurane resulted in swifter recovery and minimal side effects and proved to be a safe and reliable anesthetic for this procedure. (author's)^ieng