Biomedical subjects

R Soares

Publications and source records attributed to R Soares.

At least 19 recordsLinked to original sources

PubMed1991

Susceptibility to infection with Mycobacterium avium is paradoxically correlated with increased synthesis of specific anti-bacterial antibodies.

A comparison was made between the levels of splenic and intestinal (Peyer's patches and thin intestinal epithelium) Ig production of C57BL/6 germ free and conventional C57BL/6, BALB/c, DBA/2 and C3H/He mice and the susceptibility to Mycobacterium avium infection, evaluated by the number of bacterial colony-forming units (CFU) found in the liver and in the spleen of the animals. Mice received an i.p. injection of either 5 x 10(6), 10(7) or 10(8) bacteria, or were given the larger inoculum intragastrically. Alternatively, mice were treated with an i.p. injection of M. avium bacterial sonicates. A marked increase of splenic IgA production, quantitatively associated with the size of the inoculum and thus with the degree of infection, was observed in susceptible compared to relatively resistant mice. This increase was observed at an earlier time following infection with the larger rather than with the smaller inocula. Consistent significant increases in splenic production of IgG isotypes were only observed in the susceptible mice after infection with the intermediate and larger inocula whereas a comparative increase of IgM was only clearly observed after infection with the larger inoculum. Intestinal Ig production remained unchanged, however, in both susceptible and relatively resistant mice after i.p. infection. Also, all mice were resistant to M. avium infection by the intragastric route and with this site of entry splenic and intestinal Ig production remained unchanged. Susceptibility to M. avium infection was also quantitatively associated with increased levels of circulating specific anti-bacterial antibodies.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1990

Low T- and B-cell reactivity is an apparently paradoxical request for murine immunoprotection against Streptococcus mutans. Murine protection can be achieved by immunization against a B-cell mitogen produced by these bacteria.

C57BL/6 mice thymectomized as adults or depleted of CD4+ cells were much less susceptible than intact conventional mice to the B-cell mitogenic and specific immunosuppressive effects of a protein designated as F5'EP-Sm secreted by Streptococcus mutans. These mice were also considerably more resistant to infection by these bacteria than intact individuals. The immunosuppressor effect of F5'EP-Sm was also abrogated, however, in conventional intact mice when immunized intraperitoneally against heat-inactivated F5'EP-Sm. On the other hand, resistance to bacterial infection could be achieved by immunization of conventional intact C57BL/6 mice against heat-inactivated F5'EP-Sm by intraperitoneal or intradermal routes even when the animals were infected 3 months after immunization and even when the immunization procedure did not include Freund's adjuvant, which was the case with the intradermal route. Interestingly, the protection against the bacterial infection was accompanied by only a minor increase in specific serum antibodies against F5'EP-Sm. These results are discussed in the context of adequate strategies for immunoprotection against Streptococcus mutans and other micro-organisms which are secretors of substances that share both B-cell mitogenic and immunosuppressive properties and which are thus able to suppress the immune response by overstimulation of the immune system of the host.

Animals↗

PubMed1990

[Mitral prostheses with and without dysfunction: evaluation using 2-D Doppler echocardiography].

STUDY OBJECTIVE: To evaluate the flow characteristics of normal and abnormal functioning mechanical and bioprosthetic (B) mitral valves. DESIGN: Prospective study in patients submitted to mitral valve replacement. SETTING: Laboratory of Echocardiography at Santa Marta Hospital. PATIENTS: 61 consecutive and asymptomatic patients with normally functioning mitral prosthesis (prt)--37 Bjork-Shiley (B-S), 11 Carpentier-Edwards (C-E), 5 Hancok (HAN), 7 Ionescu-Shiley (I-S) and 1 Wessex--and 15 pts with abnormal prosthetic function (6 B-S, 5 Hall-Kaster, 2 C-E, 1 I-S and 1 HAN). INTERVENTION: Prosthetic mitral flow record, using 2D-Doppler echocardiography, to analyse: peak velocity (PV), peak gradient (PG), mean gradient (MG), pressure half time (PHT), area (A) and presence of regurgitation (R). RESULTS: Normally functioning prosthetic valves--PV ranged from 88 to 186 cm/s (134.6 +/- 24.3) in B-S prt and 133 to 198 cm/s (157.4 +/- 18.8) in B, p less than 0.0001. The prt B-S showed a greater PG (10.3 +/- 2.5 vs 7.6 +/- 2.6 mmHg), MG (3.1 +/- 1.1 vs 2.6 +/- 1 mmHg) and smaller area (2.3 +/- 0.4 vs 2.5 +/- 0.4 cm2) then Bioprosthetic ones, p less than 0.0001, p = 0.003, p = 0.003 respectively. There was a significant correlation between PG and MG: r = 0.84, r = 0.87, r = 0.84 respectively in B-S prt, Bioprosthesis and both, p less than 0.001. Mild regurgitation was present in 8 pts with prt B-S and 4 with B. Malfunctioning prosthetic valves--The mean of PV was 238.5 +/- 29.2 cm/s in prt B-S compared to 265.48.2 +/- 48.2 cm/s in B. Significant regurgitation, was detected by Doppler technic in 100% of B and 72% of mechanical prt. PV greater than 2 m/s has a 100% sensitivity and specificity to separate normal from abnormal prosthesis function. CONCLUSIONS: These data may be useful as reference values to the follow-up of pts with these types of prt. The prt B-S seems to have more optimal hemodynamics profile than B ones. Protodiastolic transprosthetic PV greater than 2 m/s suggest abnormal functioning valve. PG is a significant determinant of MG.

Adult↗

PubMed1990

[Rhythm profile in patients with psoriatic arthritis].

OBJECTIVE: To analyze the rhythmic profile in patients with psoriatic arthritis (PA). DESIGN: In order to evaluate the rhythmic profile of patients with PA, we have carried out ambulatory 24 hour ECG recordings in 22 patients presented consecutively to the Holter ECG laboratory. SETTING: Patients followed in a specialised rheumatology consultation, in Santa Maria Hospital. PATIENTS: We have studied 22 patients (pts), 10 male and 12 female, aged 49.8 +/- 8.4 years, presenting PA diagnosed in average 12.9 years before. A group of 36 individuals, 25 male and 11 female, aged 37 +/- 8 years and without disease, were used as control. RESULTS: All patients were in sinus rhythm with a mean heart rate of 71 +/- 6 (min - 51.5 +/- 7.0 and max - 130.3 +/- 15.0). In 8 (36.6%) there were sinus bradycardia less than 50/min and sinus tachycardia (greater than 120/min) in 15 patients (68.1%). Two patients (9%) presented supraventricular tachycardia and one had AV block. There were premature atrial systoles in 14 pts (63.6%), and ventricular arrhythmias in 9 (40.9%). In control group, there were sinus bradycardia in 16.6%, sinus tachycardia in 33.3%, premature atrial systoles in 33.3% and ventricular arrhythmias in 25% of them; in 11% there were conduction disturbances. CONCLUSIONS: a) Premature atrial systoles were the rhythm disturbance more prevalent. b) Patients with PA presented a significant higher incidence of sinus bradycardia and sinus tachycardia. c) Cardiac conduction disturbances were not frequent. d) Our results may suggest the presence of a subtle autonomic dysfunction in patients with psoriatic arthritis.

Adult↗

PubMed1990

[Flow in the entry chamber of the left ventricle. Changes with age].

OBJECTIVES: To evaluate the influence of aging in the parameters of the left ventricle diastolic function, using 2D-Doppler echocardiography. STUDY DESIGN: Prospective study of normals subjects. MATERIAL AND METHODS: They were studied 38 normals subjects aged between 23-70 years divided in two groups: group A--20 subjects aged less than 45 years (34.5 +/- 6) and group B--18 subjects aged greater than 45 years (55.7 +/- 8.4); we registered the left ventricle inflow flows by 2D-pulsed Doppler Echocardiography and analyzed the following indexes: E and A Velocities, E/A ratio, relations of areas under the curves of flow, E Area/Total Area (EAr/TAr), A Area/Total Area (AAr/TAr), 33% Area/Total Area (33Ar/TAr), 50% Area/Total Area (50Ar/TAr) and A Area/E Area (AAr/EAr). RESULTS: E Vel and E/A ratio are significantly higher in the group A (p less than 0.001), both decreasing with aging, respectively r = -0.71 and r = 0.63; on the other way, the relative contribution of atrial systole to the left ventricle diastolic filling is significantly higher in the group B(ArA/ArT p less than 0.001; AAr/EAr p less than 0.001), increasing significantly with aging, r = 0.64 and r = 0.69, respectively. CONCLUSIONS: There is an increasing of atrial contribution to the left ventricular diastolic filling in the elderly, so in comparative studies it must be used control groups with the same age.

Adult↗

PubMed1990

[Influence of respiratory cycle on the flows in the entry and exit chambers of the left ventricle].

OBJECTIVES: to analyse the effects of the normal respiration in the flows of left ventricle inflow and outflow tracts by Pulsed Doppler Echocardiography. STUDY DESIGN: prospective study of normal subjects. MATERIALS AND METHODS: twenty normals subjects by physical examination, electrocardiographic, radiological and echocardiographic criteria, aged between 23-70, mean 47.5 +/- 14; they were registered the inflow and outflow tracts flows simultaneously with the respiratory cycle. We analysed the peak early and end diastolic velocities and time intervals in the inflow tract flow and peak velocity and time intervals in the outflow tract and their changes with respiration. RESULTS: during expiration, there was a significative higher peak early velocity in the inflow tract and in the maximal velocity in the outflow tract of the left ventricle; there was no significative changes in the time intervals. CONCLUSIONS: it's important do not forget the changes of the different indexes used to determine the volumes, cardiac output and left ventricle function observed during normal respiration, in a normal or patient population.

Adult↗

PubMed1990

[Non-invasive evaluation of systolic pressure of the pulmonary artery in patients with tricuspid regurgitation, using Doppler echocardiography].

STUDY OBJECTIVE: To quantify the systolic pulmonary artery pressure (SPAP) by continuous wave Doppler echocardiography and record the prevalence of tricuspid regurgitation (TR). DESIGN: Prospective analysis of 42 patients (pts), submitted to right heart catheterization (RHC). SETTING: Pts referred to the Echocardiographic Laboratory at Sta. Marta Hospital - H.C.L. PATIENTS: Sequential sample of 42 pts with several cardiac pathologies, subjected to RHC and 2D Doppler Echocardiography. INTERVENTIONS: The right ventricular and SPAP were recorded in the hemodynamic exam. We considered pulmonary hypertension (PH) if SPAP was greater than 35 mmHg or mean pressure greater than 20 mmHg. The pts were divided into two groups: I-pts without PH and II-pts with PH. The 2D Doppler echocardiography was made within 24 H of the hemodynamic one. Peak gradient (pg) of TR and the correlation with catheterization data were analysed. RESULTS: Hemodynamic--The mean SPAP in the sample was 46 +/- 21.5 mmHg (27 +/- 4.6 in group I and 55 +/- 20.2 mmHg in II). In 35 pts with TR the mean SPAP was 50.3 +/- 21.2 mmHg. Doppler--The pressure gradient was 40 +/- 18.7 mmHg. 57% pts of the group I and 96% II had TR p less than 0.001. The correlation between Doppler gradient and SPAP was r = 0.95, and no change was noted when 7 is used as a constant. CONCLUSION: Continuous wave Doppler echocardiography is a non invasive technic useful to the quantitative analysis of SPAP.

Adult↗

PubMed1989

Induction of non-specific immunosuppression in mice by mycobacterial infections and its relationship to macrophage activation.

The development of non-specific immunosuppression during the infection of different strains of mice with three mycobacterial species was evaluated by studying the immune response to a heterologous antigen (sheep red blood cells) and comparing it with the induction of non-specific resistance to a Listeria monocytogenes challenge. It was shown that early (at 15 days) immunosuppression developed in Mycobacterium avium-susceptible mouse strains infected with a high inoculum dose [2.5 x 10(8) colony forming units (CFU)] of virulent M. avium but not in resistant mice infected with a similar inoculum nor in susceptible mice infected by a smaller inoculum dose (2.5 x 10(6) CFU). In the latter case it developed only during the second month of infection and was of smaller magnitude. An inoculum of M. avium of attenuated virulence did not induce immunosuppression. M. lepraemurium induced a late immunosuppression, which occurred when extensive bacterial proliferation had already taken place. The non-pathogenic M. bovis BCG induced immunosuppression in C57BL/6 mice. The results do not establish a correlation between the development of generalized immunosuppression and susceptibility to infection. It could be seen that the early immunosuppression was observed in those situations where there was extensive macrophage activation as shown by the development of non-specific resistance to a listeria challenge. The late immunosuppression was observed when bacterial proliferation was extensive.

Animals↗

PubMed1989

[Silent ischemia in patients with previous myocardial infarct. Correlation of Holter and coronarography].

OBJECTIVE: Our objective was to determine the presence of silent myocardial ischemia and the degree of coronary obstructions. DESIGN: Successively patients with myocardial infarction. SETTING: Patients admitted to the coronary intensive care, later followed in a specialised out-patients consultation. PATIENTS: 62 patients with previous myocardial infarction. INTERVENTIONS: All the patients were submitted to Holter-monitoring and coronary angiography. RESULTS: Silent ischemia was present in 14 (22,6%) of the patients. Seven of these (50%) had 3 vessels disease, 2 (14,3%) had 2 vessels disease, and 5 (35,7%) had 1 vessel disease. Twelve of the patients (86%) had occlusive lesions (greater than 90%), localised in 11 (79%) in the third proximal segment of the artery. CONCLUSIONS: Our results showed that the presence of silent myocardial ischemia was predominantly associated with 3 vessels disease, and with lesions of more than 90% of occlusion, localised in the 1/3 proximal of the vessel. Patients with previous myocardial infarction and silent ischemia may belong to a subgroup with surgical indication. And so, Holter studies in these patients should be followed by angiographic studies for localization of the obstructive lesions.

Adult↗

PubMed1988

Venous skin flaps: an experimental study and report of two clinical distal island flaps.

An experimental study of saphenous flaps in 26 dogs is reported, which confirmed the work of Baek et al. (1985) that venous flaps can survive. In addition, it showed that venous island flaps could survive after division of the venous pedicle proximally or distally, or as free flaps, providing through flow was re-established by venous anastomoses. In this study no flaps survived on a single venous pedicle without through flow. Two successful clinical cases of venous flaps are also reported, in which through flow was re-established by a simple venous anastomosis. One of these flaps threatened to become necrotic until the thrombosed anastomosis was successfully redone.

Adolescent↗

PubMed1988

Correlation between specific immunosuppression and polyclonal B cell activation induced by a protein secreted by Streptococcus mutans.

The relationship between polyclonal B cell activation and immunosuppressor effects induced by F5'EP-Sm, a non-cytotoxic protein secreted by Streptococcus mutans, was studied in C57BL/6 mice. Mice treated with F5'EP-Sm exhibited a considerable increase in splenic nonspecific Ig plaque-forming cells (PFC) compared with untreated mice. The isotypic pattern of non-specific PFC responses favours IgG2a approximately equal to IgG2b greater than IgG3 greater than IgG1 approximately equal to IgM, when taken as a ratio between treated and untreated animals. When F5'EP-Sm was administered 2 days before immunization with sheep red blood cells (SRBC), the non-specific PFC production was accompanied by an ephemeral increase in specific PFC against SRBC 1 day after immunization, which was quickly replaced by a strong immunosuppression. In contrast, when F5'EP-Sm was injected after priming, there was little or no demonstrable suppression of specific PFC, and the increase of non-specific PFC was much less evident. The kinetic curves representing increase or decrease in relation to controls of specific and non-specific PFC are almost mirror images in each of the isotypes. The in vivo suppressor effect was abrogated in thymectomized mice, although the involvement of the T cell compartment is probably secondary to the B cell mitogen effect, since T-depleted spleen cells proliferate and synthesize non-specific Ig when stimulated in vitro with F5'EP-Sm.

Animals↗

PubMed1987

Semi-purification of an immunosuppressor substance secreted by Streptococcus mutans that plays a role in the protection of the bacteria in the host.

Crude extracellular products of Streptococcus mutans (CEP-Sm) suppress the proliferative response to phytohaemagglutinin of human peripheral blood mononuclear cells and the primary immune response of C57BL/6 mice to sheep erythrocytes. This immunosuppressive effect favours the survival of the microorganism, and the bacteria lose the ability to secrete immunosuppressor substance if previously subcultured several times. Cells incubated with CEP-Sm and subsequently washed recover the ability to proliferate. Traces of CEP-Sm or to short a time of contact between CEP-Sm and the target immune system induced higher proliferative ratios or higher in vivo immune responses than controls, respectively. The proliferative values of cultures supplemented with CEP-Sm were parallel to the control values up to a certain time, after which they dropped abruptly. This drop is followed by a proliferation, and the higher the amount of CEP-Sm added to the cultures, the shorter the time until the proliferation. CEP-Sm was fractionated by means of ion exchange chromatography followed by double preparative isoelectrofocusing, ending in a subfraction of isoelectric point between 3.9 and 4.2, containing a heat-unstable material stainable by Coomassie blue but unstainable by periodic acid Schiff or methylene blue, and having a maximum optical density of 280 nm.

Animals↗

PubMed1986

A new distally based fasciocutaneous flap of the leg.

A distally based flap on the medial side of the lower leg is described. In ten cadaver dissections two perforating arteries from the posterior tibial artery were a constant finding and a flap has been designed based on these. It has been used successfully in four patients.

Adult↗

PubMed1986