Evaluation of dose due to ingestion of natural radionuclides of the uranium series in spring waters.

The concentrations of uranium isotopes and their decay products 226Ra, 222Rn, 210Pb and 210po have been analyzed in the mineral spring waters of a highly radioactive region of Brazil: Aguas da Prata. This region is located in the Poços de Caldas Plateau, one of the largest weathered alkaline intrusions in the world. Dose calculations were performed to evaluate the relative importance of these radionuclides in the exposure of the local population to radiation. Based upon concentrations measured in all the springs available, effective doses per year varying from 1.4 x 10(-4) mSv year(-1) for 238U to 5.1 x 10(-2) mSv year(-1) for 222Rn were observed. The doses from the ingestion of 222Rn, 210Po and 210Pb are of the same order of magnitude, and therefore these radionuclides are the most critical as far as the consumption of these waters is concerned.

The effects of prolonged cardiopulmonary bypass on cell-mediated immunity.

Studies of T-cell subsets (CD3+, CD4+, CD8+, CD8+ CD57+ cells), lymphocyte response to concanavalin A (Con A), phytohaemoagglutinin (PHA) and the alterations of white cell membranes shown by scanning electronic microscope (SEM) in 51 patients who underwent cardiac operation were performed. Out of these 51 unselected patients, for 16, duration of CPB was < or = 110 min (group A), while for the other 35 (group B) it was prolonged (> 110 minutes). Although variations of the lymphocyte subset observed between groups A and B were slightly significant (p < 0.05 before CPB and on postoperative day 7), the T-cell reactivity in group B in comparison to that of group A did not normalize by postoperative day 7 regardless of stimulation with PHA or with Con A. With the use of the SEM, the folded aspect of lymphocyte surface decreased after surgery in about 71% (group A) and 78% (group B) of the observed cells. The outcome of the immunological effects given by our studies could have been due to an elongated CPB even if there need to be taken into consideration multifactorial influences, i.e. biological, pharmacological and hormonal hypotheses, and rapid changes in CPB-micro-environment.

Alterations in erythrocyte morphology induced by blood pumps.

A scanning electron microscopy was used after in vitro and in vivo tests to investigate any alterations caused by the peristaltic roller pump in erythrocyte morphology. The electron micrographs of samples were examined as follows: 1) by image analyser; 2) by applying Bessis's classification for the qualitative study of crenated red blood cells (RBCs). The in vitro test was repeated four times using blood from healthy donors. Each basal blood sample was divided into 250 ml portions, each of which was recirculated for 12 minutes at different flow rates. In order to verify any persistent erythrocyte damage caused by the peristaltic pump, 15 minutes after recirculation at 450 ml/min, another sample was prepared using the blood remaining from the last test. A statistically significant direct correlation was found between blood flow (Qb) increase and the percentage of morphologically altered RBCs, when either using an image analyser (r = 0.97; p < 0.05) or Bessis's classification (r = 0.95; p < 0.05). However, neither method showed any statistically significant difference between the percentage of deformed RBCs, determined in the basal sample, or in the percentage found at the end of the 450 ml/min test after standing 15 minutes at room temperature. The in vivo test was carried out on 6 patients over 2 dialysis sessions, which differed only for the Qb: 250 versus 400 ml/min. The two dialysis sessions gave comparable results when using both study methods regarding the presence of deformed RBCs.(ABSTRACT TRUNCATED AT 250 WORDS)

Autologous hemodonation in the corrective surgery of craniostenosis.

Homologous transfusions are mandatory in most surgical procedures for correcting craniofacial malformations in infancy. A program of preoperative and intraoperative auto-hemodonation was developed and carried out in eleven infants. Although homologous transfusion could have been avoided in only 7 patients, we think that further experiences and minor corrections of our program may improve these results.

Efficacy and safety of predeposit blood autodonation in 500 cases of myocardial revascularization.

Since 1985 all patients scheduled for coronary artery bypass grafting have been evaluated for admission to a program of predeposited blood autodonation. From a total of 816 consecutive patients, 505 were admitted to the program (group 1). The other 311 (group 2) were excluded on the basis of one or more of the following criteria: 1) emergency surgical indication, 2) hemoglobin less than 12 g/dl, or 3) uncontrolled angina or clinically manifest cardiac failure. Postoperative use of homologous blood products was required by 16% of the group 1 and 44% of the group 2 patients (p less than 0.001). Altogether 597 patients (73%) had no contact with homologous blood products. There was no intergroup difference in the incidence of postoperative complications. Non-A, non-B hepatitis developed in three group 1 and four group 2 patients. Its incidence was 0.9% among all discharged patients and 3.2% of the homologous blood recipients. The findings emphasize the safety and value of the autodonation with predeposit program in significantly reducing the requirement for homologous blood in coronary artery bypass grafting.

[Blood transfusions in hemorrhage of the upper digestive tract]. / L'emotrasfusione nell'emorragia del tratto digestivo superiore.

On the basis of data published, at least three quarters of patients with acute haemorrhage of the upper digestive tract (AHUDT) undergo blood transfusions. An epidemiologic survey carried out over a period of more than two years, showed that only 322 subjects out of 587 (54.8%) with AHUDT received blood transfusions, the mean need being 3.6 +/- 6.1 units of packed erythrocytes. Our series included a relevant percentage (29%) of hepatocirrhotics, whose transfusion need was, as expected, markedly higher in comparison with the others (71% transfused versus 47.9%, and a mean of 5.3 units versus 2.9). Persistent bleeding, rebleeding rate, operation and mortality rate in our study were, respectively, 4.1%, 28.4%, 10.2% and 15.5%. Mortality among subjects non transfused was 3.4%. The adoption of restrictive criteria made it possible to avoid unnecessary blood transfusions. Patients who were hemodynamically stable with haemoglobin greater than 8 g/dl were not transfused. Our experience has shown that about fifty per cent of patients with AHUDT can be preserved from the risks connected with blood transfusions.

[Autotransfusion technic in surgery of craniostenoses in children]. / Tecniche di autoemodonazione nella chirurgia delle craniostenosi in età infantile.

The extensive blood loss during the surgical correction of craniosynostosis in infancy needs usually homologous transfusion. The Authors report a program of preoperative and intraoperative hemodilution and their experience in six infants, the very first in pediatric neurosurgery. Prevention of homologous blood transfusion achieved in 4 out 6 cases can be considered a success that could be further improved introducing minor changes in our protocol.

Normovolemic hemodilution in head and neck surgery.

As the transfusion risks to which patients are exposed are gradually understood, every effort is being made to find both a valid and safe alternative to homologous blood transfusions. Bearing this in mind, the most sensible solution appears to be the practice of a self-donor procedure with normovolemic hemodilution prior to elective surgery. However, even repeated bloodlettings do not modify the oxygen delivery to tissues since, with a reduction in the hemoglobin content of the circulating blood, there is a corresponding increase in oxygen availability. Since the reduction of circulating erythrocytes brings with it a reduction in blood viscosity, there is in turn an improvement in the microcirculation. The generally better tissue oxygenation, the reduction of the blood's viscosity and the increased circulatory perfusion all also favor a prophylaxis against deep vein thrombosis. We have currently performed 72 surgical procedures for head and neck neoplasms that were undertaken at the Clinical ENT Division of Treviso Hospital precisely with the normovolemic hemodilution described above. The self-donor transfusion technique was adopted with the help of the hospital's transfusion service. We have analyzed the data relative to this method and have found that the normovolemic hemodilution represents the treatment of choice in surgery-induced stress, particularly since this approach allows a better tissue oxygenation.

[Determination of serologic markers of hepatitis B virus in high risk areas at the Central Air Force Hospital of Peru]. / Determinación de marcadores serológicos del virus de la hepatitis B en áreas de alto riesgo del Hospital Central Fuerza Aérea del Perú.

In the present paper, the serologic markers of Hepatitis B virus were studied in 123 people belonging to the Hospital Central de la Fuerza Aérea del Perú that had been working in areas of high risk to get contact with this virus. The determination was done with the enzimo inmuno assay (EIA Abbot) and the results were the following: In 15 individuals (12.1%), at least one positive marker was found, evidence which proved to have been in contact with the virus in some moment of his life. Only one carrier (0.8%) was found, in 6 (4.8%) the presence of anti-HBc as only marker was found and in 8 (6.5%) the presence of Anti-HBc and Anti-HBs was observed which means post infection immunity. The great number of the individuals in which the markers were found, were male: 13 (16.0%) against only 2 (4.7%) female. There wasn't great difference with relation to the prevalency of markers according to the years of work like there has been observed in other greater series. It can be concluded that in this group the incidence of infection due to VHB was no greater than that of general population, which indicates us the little contact that they have had with the contaminating material during their professional life.

[The determination of serological markers of the hepatitis B virus in high-risk areas of the Central Air Force Hospital of Peru]. / Determinación de marcadores serológicos del virus de la hepatitis B en áreas de alto riesgo del Hospital Central Fuerza Aérea del Perú.

In the present paper, the serologic markers of Hepatitis B virus were studied in 123 people belonging to the Hospital Central de la Fuerza Aérea del Perú that had been working in areas of high risk to get contact with this virus. The determination was done with the enzyme immunoassay (EIA Abbot) and the results were the following: In 15 individuals (12.1%), at least one positive marker was found, evidence which proved to have been in contact with the virus in some moment of his life. Only one carrier (0.8%) was found, in 6 (4.8%) the presence of anti-HBc as only marker was found and in 8 (6.5%) the presence of anti-HBc and anti-HBs was observed which means post infection immunity. The great number of the individuals in which the markers were found, were male: 13 (16.0%) against only 2 (4.7%) female. There wasn't great difference with relation to the prevalence of markers according to the years of work like there has been observed in other greater series. It can be concluded that in this group the incidence of infection due to VHB was no greater than that of general population, which indicates us the little contact that they have had with the contaminating material during their professional life.