Rapid non-enzymatic HPLC determination of total MHPG in human plasma

We have previously reported a method for the determination of total 3-methoxy-4-hydroxy phenylethylene glycol (MHPG) in brain, based on a simple acid-catalyzed hydrolysis. Now we extend this procedure to the determination of plasma total MHPG. The method involves the deproteinization of plasma with perchloric acid, followed by 3 minutes of an acid-catalyzed step. The hydrolysates are injected into the HPLC system, using a formic acid/methanol eluent with fluorimetric detection. Sample detection limit is below 1 ng MHPG/mL of plasma. This procedure has been used for the determination of plasma total MHPG from 109 healthy individuals of both sexes. Mean value was: 5.4 + 2.3 ng total MHPG/mL of plasma (means +/- S.D., N = 109). No sex differences were observed, and a slight correlation with age (r = 0.24, p less than 0.02) has been found. Plasma-free MHPG was also determined in a subgroup of 15 randomly chosen individuals (3.0 +/- 1.2 ng free MHPG/mL plasma, means +/- S.D.). A significant correlation was obtained with plasma total MHPG (r = 0.77, p less than 0.001, N = 15). The main advantage of the present method lays in its simplicity, since no enzymatic hydrolysis or extraction procedures are needed, being its reliability fully proven through 109 plasma total MHPG determinations.

[Doppler echocardiographic evaluation of heart transplantation]

In order to evaluate major Doppler-Echocardiographic parameters for the diagnosis of acute cardiac allograft rejection episodes a serial of 54 Doppler Echocardiograms were performed simultaneously with endomyocardial biopsy in five patients (mean age = 40.2 y/o). Measurements included: right and left chambers diameters, left ventricular (LV) myocardial diastolic thickness, LV systolic function parameters, LV mass, LV volume/mass ratio, LV isovolumic relaxation time, mitral flow peak velocities and pressure half-time. Episodes with acute rejection histopathologic findings, Billingham class III or IV, were associated to increase in LV free wall thickness and LV mass (p less than 0,005) as well as decreased isovolumic relaxation time and pressure half-time (p less than 0,001). Left ventricular systolic function parameters and heart rate were no different comparing rejection and no rejection episodes. However, in each patient, progressive lower values of LV ejection fraction were associated to higher incidence of acute rejection episodes. Isovolumic relaxation time increased promptly following immunosuppressive therapy. Thus, Doppler Echocardiography is a reliable method for early detection of acute cardiac allograft rejection and monitoring of the cardiac transplant recipient.

[Morphologic findings in systemic amebiasis. Apropos of 1 case]

Amebiasis is an uncommon infectious disease in our region. We describe the anatomopathologic findings of the autopsy of a patient who died of systemic amebiasis, briefly commenting the anatomo-clinical characteristics of this disease and its diagnosis.

A multicenter, randomized, double-blind study comparing once-daily bedtime administration of famotidine and ranitidine in the short-term treatment of active duodenal ulcer

The efficacy and safety of famotidine and ranitidine in the treatment of active duodenal ulcer were compared in a multicenter, randomized double-blind study. The study was carried out at 5 centers and involved a total of 143 patients with endoscopically documented active duodenal ulcer. The patients received either famotidine (1 40 mg tablet at night) or ranitidine 2 150 mg tablets at night). Endoscopic examinations were performed at 4 and 6 weeks of active treatment. Day and nocturnal pain were also monitored, and the laboratory and clinical profiles evaluated. One hundred and thirty-three patients fulfilled the evaluation criteria (66 patients in the famotidine group and 67 in the ranitidine group). Healing rates at weeks 4 or 6 of treatment showed no significant differences between the famotidine group and the ranitidine group. The healing rates were 78% at week 4 and 96% at week 6 in the famotidine group, and 76% at week 4 and 95% at week 6 in the ranitidine group. Similar results were observed in both treatment groups with regard to pain resolution, decrease in antacid intake and safety profile.

A multicentre, randomized, double-blind study comparing nocte famotidine or ranitidine for the treatment of active duodenal ulceration

The efficacy and safety of famotidine and ranitidine in the treatment of active duodenal ulcer were compared in a multicentre, randomized, double-blind study. The study was carried out in five centres which included a total of 143 patients with endoscopically documented active duodenal ulcer. The patients received either famotidine (one tablet of 40 mg at night) or ranitidine (two tablets of 150 mg at night). Endoscopic examinations were performed at 4 and 6 weeks of active treatment. Daytime and nocturnal pain were also monitored, and the laboratory and clinical profiles evaluated. One hundred and thirty-three patients fulfilled the evaluation criteria (66 patients in the famotidine group and 67 in the ranitidine group). Healing rates at 4 or 6 weeks of treatment showed no significant differences between the famotidine and ranitidine groups. The healing rates were 80% at week 4 and 97% at week 6 in the famotidine group, and 77% at week 4 and 96% at week 6 in the ranitidine group. Similar results were observed in both treatment groups with regard to pain resolution, decrease in antacid intake and safety profile.

A multicenter, randomized, double-blind study comparing a daily bedtime administration of famotidine and ranitidine in short-term treatment of active duodenal ulcer

The efficacy and safety of famotidine and ranitidine in the treatment of active duodenal ulcer were compared in a multicenter, randomized double-blind study. The study was carried out in 5 centers which included a total of 143 patients with endoscopically documented active duodenal ulcer. The patients received either famotidine (1 tablet of 40 mg at night) or ranitidine (2 tablets of 150 mg at night). Endoscopic examinations were performed at 4 and 6 weeks of active treatment. Day and nocturnal pain were also monitored and the laboratory and clinical profiles evaluated. One hundred and thirty-three patients fulfilled the evaluation criteria (66 patients in the famotidine group and 67 in the ranitidine group). Healing rates at weeks 4 or 6 of treatment showed no significant differences between the famotidine and the ranitidine groups. The healing rates were 79% at week 4 and 96% at week 6 in the famotidine group, and 77% at week 4 and 95% at week 6 in the ranitidine group. Similar results were observed in both treatment groups with regard to pain resolution, decrease in antacid intake and safety profile.

Biogenic amines stimulate regeneration of cilia in Tetrahymena thermophila

Serotonin and catecholamines affect the regeneration of cilia in Tetrahymena thermophila in a dose-dependent manner: micromolar concentrations are stimulatory, whereas millimolar concentrations have little or no effect. This conclusion is based on motility measurements in regenerating cells and on ciliary counts in scanning electron micrographs. In addition, the recognition mechanism for each hormone appears to be specific and independent. Our results suggest an evolutionary link with hormonal mechanisms in multicellular eukaryotes.

Serotonergic status in human blood

Preliminary data on the existence of a plasma pool of serotonin (5HT) in human blood has been confirmed in a descriptive study of two distinctive pools of 5HT (plasma and platelet), and its metabolite 5-hydroxyindoleacetic acid (5HIAA), in the blood of 175 healthy individuals. Plasma 5HT (0.93 +/- 0.67 ng/mL, X +/- S.D.) shows a significant but low correlation with platelet 5HT (711 +/- 319 ng/10(9) platelets) (r=0.29, p less than 0.001). Diastolic blood pressure correlated significantly with plasma 5HT (r=0.51, p less than 0.05) and whole blood 5HT (r=0.52, p less than 0.05) in older individuals (50-65 years) but not in the whole group (r=0.052, n.s.). Differences between sexes include plasma 5HT, whole blood 5HT (both higher in women) and plasma 5HIAA (lower in women) and may reflect a differential whole body 5HT function. The effect of meal consumption and a peripheral 5HT synthesis inhibitor (carbidopa) in four human subjects has also been tested. Carbidopa (0.7 mg/kg) significantly lowers the plasma pool of 5HT (mean change -33%) 2 hr. after administration, while platelet 5HT is unchanged. These data support the existence of a human plasma 5HT pool, with a rapid turnover, different from the 5HT in platelets (slow turnover, reserve pool). Both may be useful in evaluating different aspects of 5HT-mediated pathologies.

Coagulation defects during extracorporeal circulation in the dog

This study was undertaken in an attempt to diminish the frequency and severity of postextracorporeal circulation hemorrhage in dogs. Its purpose is to ascertain the amount of 99mTc-labeled autologous fibrinogen deposited in the oxygenator, as well as the coagulation defect originated during the surgical procedure when heparin is not administered (group I) and when it is at doses of 1 mg/kg body weight (group II) and 3 mg/kg body weight (group III). The result demonstrate that the fibrinogen deposition in the oxygenator decreased as the dose of heparin administered was augmented. The coagulation disorders were produced by factor consumption, affecting all dogs in group I. The same type of alteration was produced with the use of heparin, but in some the platelet count, fibrinogen and fibrinogen degradation products and the prothrombin and thrombin times were maintained within normality or were only slightly altered. Significant differences were not detected between groups II and III. For this reason, we recommend the utilization of heparin in experimental extracorporeal circulation in a single dose of 1 mg/kg body weight, administered at the initiation of bypass, which provides a sufficient level of anticoagulation for at least 60 min and makes its neutralization with protamine unnecessary, the effects of which are especially adverse in the dog.

Localization and comparative nucleotide sequence analysis of the transforming domain in herpes simplex virus DNA containing repetitive genetic elements

The 7.5-kilobase BamHI E fragment (BamHI-E) of herpes simplex virus type 2 (HSV-2) DNA (map position 0.533-0.583) encodes the 144-kDa subunit of ribonucleotide reductase and induces the neoplastic transformation of immortalized cell lines. To define the minimal transforming region of BamHI-E, a series of subclones were constructed that spanned the entire fragment. These subclones were assayed for focus formation in Rat-2 cells. Removal of the promoter region from the viral 144-kDa-protein gene left the transforming activity of DNA clones intact. A 481-bp Pst I-Sal I subclone of BamHI-E was capable of inducing focus formation and tumorigenic conversion. The nucleotide sequence of this fragment and the colinear nontransforming region of HSV-1 DNA was determined and compared. Striking differences were detected in the structure and organization of repeated sequence elements. Specifically, transforming HSV-2 DNA contains multiple regions of alternating purines and pyrimidines, G + C-rich sequences that are potential binding sites for transcription factor Sp1, and insertion-like sequence elements that are interrupted by base substitutions in nontransforming HSV-1 DNA. These results define a distinct transforming domain in HSV-2 DNA composed of repetitive elements implicated in gene rearrangement and activation.

Effects of different doses of acetylsalicylic acid on platelet aggregation: an experimental study of prosthetic materials in dogs

Laminar flow is the condition best suited to the study of platelet thrombi. This type of thrombus is predominant in arteries, in the tubes of cannulas used in artificial circulatory systems, in cardiac valve prostheses and in prosthetic arterial implants. Antiplatelet drugs could, in these cases, reduce the extent of thrombus formation. At present the optimal dose of acetylsalicylic acid (ASA) to achieve the best antithrombotic effect is unknown; some papers show that high doses augment experimental thrombosis. By means of autologous platelets labelled with 111In-oxine, we have quantified the accumulation on different materials used in cardiovascular surgery (woven, knitted and double velour Dacron, Avcothane 51 elastomere and smooth surface and rough surface pericardium). Samples of these fabrics were placed in a laminar flow chamber connected between the right atrium and femoral artery of the experimental animals (dogs). The animals were divided into four groups of eight dogs: Group I: no treatment Group II: animals treated one week earlier with ASA (1 mg/kg/day) Group III: as in Group II, but at a dose of 5 mg/kg/day Group IV: as in Group II, but at a dose of 20 mg/kg/day. The materials upon which the least amount of platelets were accumulated were the smooth, epicardial surface of pericardium (SP) and Avcothane (AV). The least deposition was produced in Group III, with the exception of SP. In the case of this material, there was no difference between Groups I and III. In Group IV, the deposit was greater with respect to the untreated group (Group I), except in the case of AV, in which there was no difference between Groups I and IV.