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Biomedical subjects

J Vega

Publications and source records attributed to J Vega.

At least 91 records · Page 5Linked to original sources
PubMed1979

Antibody-independent activation of complement by human peripheral B lymphocytes.

Normal human peripheral blood lymphocytes were shown to activate complement in normal human serum (NHS). This activation led to C3 fixation on the cell membrane, which in turn was visualized by fluorescence. The reaction occurred in the absence of detectable amounts of antibodies, since an agammaglobulinemic patient's serum also supported complement activation, and the results were unaltered by absorption of normal human serum. Trypsin treatment of lymphocytes to remove possible complement activators bound to the cell membrane, did not have any effect on the complement activation by lymphocytes. Complement membrane fluorescence was abolished in the presence of EDTA or ethyleneglycolbis(aminoethylether) tetraacetate (EGTA) supplemented by Mg++ions indicating that the classical pathway of complement activation was involved in the reaction. Experiments performed with T and B-purified populations showed that the phenomenon was confined to the B cell fraction. Complement deposition did not diminish the number of EAC rosettes, and viability remained unchanged after exposure of lymphocytes to normal human serum.

Agammaglobulinemia↗
PubMed1979

Purification of human T and B cells by a discontinuous density gradient of percoll.

A simple technique for isolating human peripheral B and T cells is described. This method is based on the different mobility of cells in a discontinuous density gradient of Percoll. A population with a mean of 72.8% of surface stable Ig (B cells) is found in the top layer (fraction I) whereas T cells with less than 3% of Ig are distributed in the two lower layers (fractions II and III). B cells obtained by this method were highly viable and reacted strongly with anti-DRw specific sera, whereas T cells did not respond. The clear-cut difference between positive and negative reactions makes this technique very suitable for DRw typing. The proliferative response to PHA is decreased in fractions I and III while greatly increased in fraction II. The different mitogenic responses in the two fractions containing T cells probably represent two functionally distinct T cell subsets. Cells from all fractions are less activated than unseparated cells when Con A and PWM are used as mitogen. The technique is very rapid, avoids the interaction of cells with their specific receptors and gives both T and B cells in one step, all advantages over other methods commonly used.

Antilymphocyte Serum↗
PubMed1978

["Yersinia pseudotuberculosis" in a case of mesenteric lymphadenitis (author's transl)].

An eleven-year old girl's case of an inflammatory process of the right lower abdomen is described, with a positive agglutination reaction to "Y. pseudotuberculosis", serotype I-A. The surgical operation disclosed a normal coecal appendix as well as a mass of clustered ganglionar adenopathies, exclusively located in the ileo-coecal junction. Histologic findings were a pulpar and follicular hyperplasia with mastocytes accumulation and metachromatic staining of capsule and connective tissue. From homogenized ganglionar mass an agent was isolated, further identified as "Y. pseudotuberculosis" type I-A. A comment follows on the frequency of mesenteric lymphadenitis as cause of inflammatory processes of the lower right abdomen in children and the rarity of isolation of "Y. pseudotuberculosis" as etiological agent as compared with the more common "Y. enterocolitica".

Child↗
PubMedDate not supplied

Mechanical circulatory support for perioperative donor heart failure.

Perioperative acute donor heart failure can be caused by various factors, such as recipient pulmonary hypertension, marginal donor heart function, or immunologic mismatch. Of 265 patients who underwent orthotopic transplantation, four received mechanical support for acute perioperative donor heart failure. In two patients with reactive pulmonary hypertension, right heart bypass (RHB) with a centrifugal pump was used for 53 and 36 hr, respectively. One patient who experienced biventricular donor heart failure was supported for three days with an intraarterial, transvalvular, axial-flow left ventricular assist device (LVAD). Circulation was supported effectively with the LVAD, despite an initial absence of right ventricular function. The fourth patient, who had signs of heart failure, received intraaortic balloon pump support for 24 hr after transplantation. All four patients were weaned from circulatory support, and heart function was restored in each; the mean left ventricular ejection fraction was 63% (range from 57 to 71%). One patient died of fungal infection 14 days after being weaned from pump support, another died of lymphoma two months after support was discontinued, and the remaining two patients are well 9 and 18 months after transplantation. In cases of acute donor heart dysfunction, temporary mechanical assistance is a reliable option for supporting the circulation during heart recovery.

Adult↗
PubMedDate not supplied

Morbidity and mortality following abdominoperineal resection for low rectal adenocarcinoma.

BACKGROUND: Abdominoperineal resection (APR) has been the standard treatment of low rectal cancer, but it is associated with significant morbidity and mortality. AIM: To analyze the morbidity and mortality rates associated with this surgical procedure performed at a tertiary-level cancer center. MATERIALS AND METHODS: From 1995-1999, 137 patients with rectal cancer located between 0 and 8 cm from the anal verge underwent APR. Covariates were analyzed mean chi 2 and those favorable or adverse covariates affecting the perineal infection and recurrences were analyzed by logistic regression analysis. RESULTS: There were 78 males and 59 females, with a mean age of 57.4 +/- 14.6 years. Mean intraoperative hemorrhage was 739 +/- 547 mL; 51 (37.2%) patients received blood transfusion. Seventy-two patients received preoperative radiotherapy (PRT): 22, postoperative chemo-radiation therapy; 21, PRT + chemotherapy, and 22, APR only. Seventeen patients (12.4%) had major complications and 47 (34.3%) had minor complications. Twenty patients (14.6%) developed perineal wound infection. The main factors influencing these complications were administration of PRT +/- chemotherapy and age over 55 years. Operative mortality was 0.7%. Median follow-up was 32 months. Twelve patients (8.8%) had local recurrence and 35 (25.7%) had distant recurrence. Overall five-year survival was 75%. CONCLUSIONS: APR is a surgical procedure associated with significant morbidity but low postoperative surgical mortality. The main cause of morbidity was perineal would infection influenced by administration of PRT +/- chemotherapy and age over 55 years. However, this treatment association is linked with low rate of local recurrence.

Abdomen↗
PubMedDate not supplied

[Doppler echocardiography in the diagnosis of mechanic complications of acute myocardial infarction].

OBJECTIVES: To evaluate the ability of bedside emergency Doppler/Echocardiographic (ECOCG/DP) studies in the diagnosis of mechanic complications during acute myocardial infarction (AMI). DESIGN: Retrospective analysis of 44 fatal AMI cases, studied by ECOCG/DP and with diagnostic confirmation by surgery and/or necropsy. SETTING: Patients (pts) with AMI admitted to an Intensive Care Unit of a tertiary Hospital (UCIM), Hospital de Santa Maria. PATIENTS: 44 fatal AMI cases were analysed (24 men and 20 women; mean age +/- SD: 72 +/- 9 years) and were divided in two groups according to Killip classification in Group 1 (III/IV): 35 pts and Group 2 (I/II): 9 pts. METHODS: ECOCG/DP was performed in a routine basis at admission, using all standard views and by subcostal view when in an emergency scenario. RESULTS: In 20 pts with bad left ventricular function (LVF) (Group 1) at admission, ECOCG/DP monitoring showed that death was due to worsening of LVF, which was confirmed by necropsy. In the other 15 pts of this group, ECOCG/DP documented the clinical diagnosis of cardiac rupture (free wall: 4 pts; papillary muscle: 4 pts; interventricular septum: 7 pts) which was confirmed by surgery and/or necropsy. In the 9 pts of Group 2, ECOCG/DP disclosed, at admission, good LVF in all. In 5 pts there was a sudden worsening clinical status, and ECOCG/DP showed a severe pericardial effusion with right chambers collapse, highly suggestive of free wall rupture also confirmed at necropsy. In the other 4 pts, ECOCG/DP showed aggravation of wall motion abnormalities and of LVF without rupture, once again in agreement with necropsy. Five clinical cases are presented for illustration of this issue. CONCLUSION: In the 44 fatal AMI cases of our study there was complete agreement between the ECOCG/DP and necropsy studies. In AMI patients, ECOCG/DP monitoring can in a routine basis, evaluate wall motion abnormalities and LVF. In an emergency setting ECOCG/DP can diagnose all the mechanic complications with a great certainty.

Aged↗
PubMedDate not supplied

[Lead exposure and its effects on child health].

Childhood lead poisoning is a man-made disease whose magnitude has not yet been measured in Chile. In the U.S.A. it has been estimated that 4 percent of children have elevated blood lead levels and that among poor black children, this rate is as high as 18 percent. The main sources of symptomatic lead poisoning are lead-based paint used in interior and exterior house surfaces, airborne lead from leaded gasoline and industrial emissions. Lead can be transferred from any source to soil and dust. Other sources of lead are contaminated food and water, occupational sources, and lead glazed pottery. Neurological symptoms (hyperactivity, distractibility, lower intellectual development), psychological difficulties (behavioral deficits), hematologic abnormalities (reduction in the biosynthesis of heme, anemia), and metabolic changes (reduction in concentration of 1-25 dihydroxy vitamin D and in the metabolism of erythrocyte pyrimidine) have been shown to occur in lead poisoning. Recent data suggests that prenatal exposure to lead my be related to minor congenital abnormalities, tumors of the kidney, and growth abnormalities.

Air Pollution↗
PubMedDate not supplied

[Mortality due to lesions in accidents and violence in children under 20 years of age].

Given the importance of injury's associated mortality in children, the total number of deaths caused by injuries in subjects under 20 years of age along years 1982 through 1987 in Chile, were studied. The Annals of Mortality and Causes of Death of the Chilean National Institute of Statistics were reviewed for that period. The average annual injury's death rate was 21.95 per 100,000 inhabitants younger than 20 years. Suffocation, motor vehicle accidents, burning and drowning were the leading causes of death by injuries. In infants, the main reported cause of death was suffocation (90.1% of the total deaths). Motor vehicle accidents were the leading cause of death for children aged 5 to 19 years. Fifty percent of the total deaths occurred in children aged less than one year. The total injury death rate trend remained stable over the analyzed period. The same occurred for deaths due to motor vehicle accidents in 5 to 19 years old. The trend for deaths by suffocation in children aged less than one year has clearly increased during the period, as is also the case for the proportion due to this same cause over the total number of deaths.

Accidents↗
PubMedDate not supplied

[The role of cellular contacts in the recovery of the ion channels of epithelial cell membranes].

Cationic currents in mature MDCK cells are almost exclusively due to K+ channels. Harvesting with trypsin-EDTA destroys 80-90% of these channels. Upon replating, K+ currents recover in 12-20 h, by means a process that requires synthesis of proteins and of RNA. In the present work we demonstrate that this restoration depends on a Ca2+ activated-cell contact. Thus, cells in confluent monolayers bathed with 1.8 mM Ca2+ have a K+ current of 343 +/- 82 pA; confluent without Ca2+ have only 90 +/- 12 pA (27% of control; and without cell-cell contacts incubated with 1.8 mM Ca2+ (subconfl+Ca2+) have 104 +/- 21 pA (31% of control). This demonstration that the expression of K+ channels depends on Ca-activated cell-attaching molecules suggests that a molecule of the type of uvomorulin is involved.

Animals↗