Effect of antibodies to intercellular adhesion molecule type 1 on the protection of distant organs during reperfusion syndrome in rats

We investigated kidney and lung alterations caused by intercellular adhesion molecule type 1 (ICAM-1) blockade after ischemia and reperfusion of hind limb skeletal muscles. Rats were submitted to ligature of the infrarenal aorta for 6 h. The animals were randomized into three groups of 6 rats each: group I, sacrificed after ischemia; group II, reperfusion for 24 h, and group III, reperfusion for 24 h after receiving monoclonal anti-ICAM-1 antibodies. At the end of the experiment, blood samples were collected for creatinine, lactate dehydrogenase, creatine phosphokinase, potassium, pH and leukocyte counts. Samples were taken from the muscles of the hind limbs and from the kidneys and lungs for histological analysis and measurement of the neutrophil infiltrate by myeloperoxidase staining. The groups did not differ significantly with regard to the laboratory tests. There were no major histological alterations in the kidneys. An intense neutrophil infiltrate in the lungs, similar in all groups, was detected. Myeloperoxidase determination showed that after reperfusion there was significantly less retention of polymorphonuclear neutrophils in the muscles (352 ± 70 vs 1451 ± 235 I 10² neutrophils/mg; P<0.01) and in the kidneys (526 ± 89 vs 852 ± 73 I 10² neutrophils/mg; P<0.01) of the animals that received anti-ICAM-1 before perfusion compared to the group that did not. The use of anti-ICAM-1 antibodies in this experimental model minimized neutrophil influx, thus reducing the inflammatory process, in the muscles and kidneys after ischemia and reperfusion of the hind limbs

Paradoxical sleep deprivation increases plasma endothelin levels

The endothelins (ET-1, 2 and 3) constitute a family of 21 amino acid peptides with potent biological activities. ET-1 is one of the most potent endogenous vasoconstrictors so far identified and its increased concentration in plasma appears to be closely related to the pathogenesis of arterial hypertension as well as to obstructive sleep apnea (OSA). OSA patients exhibit repetitive episodes of apnea and hypopnea that result in hypoxia and consecutive arousals. These patients are chronically sleep deprived, which may aggravate the hypertensive features, since literature data show that sleep deprivation results in hypertension both in humans and in animals. Based on the reported relationship between ET-1, hypertension and sleep deprivation consequences, the purpose of the present study was to determine plasma ET concentrations in paradoxical sleep-deprived animals. Male Wistar rats, 3 to 4 months old (N = 10 per group), were deprived of sleep for 24 and 96 h by the platform technique and plasma ET-1/2 was measured by radioimmunoassay. Analysis of plasma revealed that 96 h of sleep deprivation induced a significant increase in ET-1/2 release (6.58 fmol/ml) compared to control (5.07 fmol/ml). These data show that sleep deprivation altered plasma ET-1/2 concentrations, suggesting that such an increase may participate in the genesis of arterial hypertension and cardiorespiratory changes observed after sleep deprivation

Quantificaçäo da interferência do soro na fagocitose de imunocomplexos nas espondiloartropatias soronegativas, lúpus eritematoso sistêmico e doença reumatóide / Quantification of serum interference in the immune complexes phagocytosis in seronegative spondylarthropaties, systemic lupus erythematosus and rheumatoid disease

Cinqüenta e cinco soros de pacientes portadores de espondiloartropatias soronegativas, lúpus eritematoso sistêmico e artrite reumatóide foram selecionados para o estudo. Todos os soros mostravam fator reumatóide negativo pela prova de látex. A determinaçäo da interferência na fagocitose de gamaglobulina agregada por macrófagos de cobaia foi obtida por uma fórmula. A caracterizaçäo dos soros foi discriminada pela reaçäo daqueles que mostraram resultados mais expressivos na interferência sobre a fagocitose, facilitando ou inibindo-a. Os resultados, em valores absolutos e percentuais, mostraram a predominância do fenômeno da interferência na fagocitose, com valores significantes estatisticamente (p<0,05), quando comparado com soro normal. A análise comparativa entre as doenças estudadas na quantificaçäo da interferência do soro na fagocitose de imunocomplexo näo mostrou diferença significativa. A inibiçäo da fagocitose ocorreu com mais predominância no soro de pacientes com síndrome de Reiter e artrite psoriática; no soro de pacientes com síndrome de Reiter houve uma diferença estatisticamente significante na inibiçäo da fagocitose (p=0,0247). A caracterizaçäo da fraçäo sérica responsável pela interferência na fagocitose näo foi demonstrada. No estado atual dos conhecimentos, näo há uniformidade nas curvas de diluiçäo estudadas. É enfatizada a possibilidade de existência de mais de um elemento interferindo na fagocitose de imunocomplexos.

Wa idiotype in seropositive rheumatoid arthritis

Antibodies against cross-reactive idiotypes (CRIs) may prove useful as phenotypic tracers of immunoglobulin variable region genes (VH or VL). CRIs of human rheumatoid factors (RFs) seem to be useful in the elucidation of the incidence and structural characteristics of the latter. Anti-Wa CRI antibodies were produced and an enzyme immunoassay was developed to test polyclonal RFs isolated from sera of 20 rheumatoid arthritis (RA) patients, 7 males and 13 females, aged 17 to 74 years. Seventeen patients had clinically active disease and three were in remission. Disease duration ranged from 1 to 25 years and RF titers ranged from 1:160 to 1:640. The immunoassay could detect as little as 8 ng of a monoclonal purified WaRF and positive results were found in 30 per cent of patient sera. Therefore, we may conclude that at least part of the RFs seen in RA patients derives from germ line genes

A simple radial immunohemolysis assay for the measurement of functional complement C2 activity / O ensaio simples de imunohemolise radial para medir da atividade funcional do complemento 2

This study describes a simple radial immunohemolysis method for determining the hemolytic activity of the second component of complement (C2) in human serum. The assay is based on the recovery of hemolytic activity of normal serum which has been pretreated to anactivate endogenous C2 and thenmixed with test serum containing an unknown amount of C2. The pretreated serum, designated R2 reagent, is obtained by heating normal human sera under carefully standardized conditions of temperature, time, volume and type of test tube. R2 reagent is incorporated into agarose together with hemolysin-sensitized erythrocytes, and spread om a plate. The test serum is placed in wells cut in the agarose and, after appropriate incubation, the diameters of the hemolytic areas are measuremed.The area of hemolysis is directly proportional to the logarithm of the serum concentration.As a standard for C2 functional activity, dilutions of a pool of normal sera are tested on the same plate. The method is specific for C2 and can deted as little as 20% of the C2 in normal serum (abouth 6 *g C2 protein/ml). The error in reproducibility is about 3% of the mean.in normal serum, the lower confidence limit of the distribution of the C2 values (based on a sample of 80 individuals) corresponded to 70 % of undiluited serum. This method is sultable for use in clinical laboratories since it is simple, rapid quantitative ans inexpensive, and does not require special equipement

Protein-losing enteropathy in systemic lupus erythematosus

Enteropatia perdedora de proteina no lupus eritematoso sistemico. O caso de uma jovem de 23 anos com lupus eritematoso sistemico e enteropatia perdedora de proteina e descrito. A biopsia de delgado revelou linfangiectasia. O quadro regrediu com o uso de prednisona. A enteropatia perdedora de proteina deve ser suspeitada nos casos de lupus eritematoso sistemico com hipoalbuminemia e funcoes hepatica e renal preservadas. A revisao da literatura e apresentada salientando-se os aspectos fisiopatologicos envolvidos.

Critical study of the effect of temperature on total serum complement determination

Basic rules establish that the total serum complement determination (CH50) should be done after quick serum separation at 4 degrees Celsius. When there is a long period between blood sample collection and laboratory tests, the results may not be exact, with findings being below normal level due to thermolability and dysfunction of some of the components. Sera from 15 normal individuals and 15 patients with Systemic Erithematous Lupus (SEL) were studied. CH50 determinations were performed by the radial immunohemolysis technique according to the above basic rules and compared to determinations performed after 4, 8, 12 and 24 h in sera maintained at room temperature and after 24 h in those maintained at 4 degrees Celsius. Five samples (2 controls and 3 lupoid) were stored at -2O degrees Celsius and -7O degrees Celsius. CH50 determinations were performed weekly in sera kept at -2O degrees Celsius and after l month in those stored at -7O degrees Celsius. Analysis of the results suggest that, if blood samples are kept at room temperature and the determination is performed within about 8 h, the results are still reliable, that is, they will be within normal levels. The same will happen if the sera are stored at -2O degrees Celsius or -7O degrees Celsius for up to l month.