[Morphological and ultrastructural changes in the rat kidney after experimental sepsis]. / Morfologicheskie i ultrastrukturnye izmeneniia kletok v pochkakh krys posle éksperimental'nogo sepsisa.

UNLABELLED: Experimental sepsis was investigated in 42 male white Wistar rats. The animals were divided into 7 equal groups. Suspended E. coli cells (2 x 10(7) per 100 g body weight) were injected into the tail vein in groups I-VI, group VII served as a control group. The rats were sacrificed with cervical dislocation at different times after injection: in 45 min (group I), 2 h (group II), 6 h (group III), 24 h (group IV), 48 h (group V), and 120 h (group VI). Samples of kidneys were taken and embedded in paraffin and EPON-812 for histological and electron microscopical evaluation, respectively. RESULTS: histological examination demonstrated that changes in kindeys started in 2 h after infection to achieve the maximum level in 24 h, showing thereafter a tendency to decrease. A significant tissue damage was first seen in the loop and distal tubules of nephrons, and then expanded to the proximal tubules. Electron microscope examination demonstrated that changes in podocytes and cytopodia could be distinctly differentiated in 2 h after infection and obviously increased in the course of the experiment. The podocytes were enlarged, the processes were expanded and adhered to each other. For that reason the number of filtration pores in the glomerular basal membrane decreased. The count of mesangial cells in the glomerulus was increased.

Dissemination of bacteria in multiple organs associated with apoptosis and macrophage activity in different stages of experimental sepsis.

BACKGROUND: Gram negative sepsis is reported to induce massive translocation of bacteria into tissues, which associates with decreased macrophage function and increased macrophage apoptosis. AIMS: The objective of this study was to detect the translocation of bacteria into different organs and to evaluate macrophage activity and the apoptosis of macrophages in the liver during different stages of sepsis and to correlate these parameters. MATERIAL: Wistar rats (n = 43) were inoculated intraperitoneally with an E. coli and divided into 5 groups, which were killed at different times. METHODS: Counts of translocated bacteria in tissues were evaluated by using morphological and bacteriological methods. Macrophage activity and apoptotic cells in the liver were studied by applying immunohistochemical methods. RESULTS: The counts of E. coli were the highest in the organs and blood 6 h after the onset of sepsis, being in correlation with the highest counts of apoptotic cells in the liver and the falling counts of activated macrophages. The counts of microbes show a new wave of elevation in tissues by 120th h. CONCLUSIONS: The massive penetration of bacteria, the depressed macrophage response in early sepsis following the increased rate of apoptotic macrophages, the different rate of bacterial multiplication in tissues and blood and the second wave of the multiplication of bacteria in tissues in late sepsis all refer to the significance of developing immune dysfunction.

Bacterial dissemination and the value of blood cultures in patients who die of septic shock.

The aim of this study was to determine whether blood cultures reflect real bacterial dissemination into the tissues of patients who die of septic shock. A total of 20 patients were divided into two groups with surgical (nine) and nonsurgical (11) sepsis. Blood cultures were taken and the adequacy of antibacterial therapy was assessed. Postmortem tissue samples of different organs were studied using light microscopy for the presence of bacteria. A semiquantitative measure, the contamination index, was applied. Despite negative blood cultures from 14 patients, bacteria were found in almost all of the organs examined from all of the patients. There was no difference in contamination index between patients who received adequate antibacterial therapy and those who did not. We conclude that septic shock is the manifestation of bacterial dissemination into the organs, and that blood cultures are of limited value in the diagnosis of sepsis, especially when they are taken during adequate antibacterial therapy.

Translocation of indigenous microflora in an experimental model of sepsis.

Translocation of viable bacteria from gut to bloodstream and other sterile body sites during shock has been demonstrated in several experimental and clinical studies. The factors causing translocation and its incidence at different stages of shock are not known. The aim of the study was to evaluate the importance of several factors causing translocation of indigenous microflora in an experimental model of septic shock based on intraperitoneal Escherichia coli sepsis in rats. Counts of inoculated E. coli and translocated bacteria in different locations, gut morphology and haematological values were evaluated at different stages of sepsis. Sepsis developed in all animals and E. coli achieved the highest counts in blood 6 h after inoculation. Translocation was commonest at 6 and 12 h after inoculation. Frequently translocating bacteria were lactobacilli, bifidobacteria, bacteroides and peptostreptococci. In early sepsis, translocation was associated with high E. coli counts in blood, yet in late sepsis the opposite correlation was present. Low infiltration by neutrophils in the ileum and decreased mitotic activity in the colon were associated with a high translocation rate. In early sepsis, translocation was associated with low lymphocyte counts, but in late sepsis, with low neutrophil counts. Translocation of bacteria (including anaerobes) that colonise the gut in high counts takes place during sepsis. Putative influencing factors such as activity of the primary disease (bacterial counts in blood), gut morphology or haematological values seem to have different impacts on translocation, depending on the stage of the disease.

Septic shock with disseminated microfoci in multiple organs in humans.

OBJECTIVE: Histological assessment of tissue damage and localisation of bacteria in autopsy materials of patients who died of septic shock. DESIGN: Prospective observational study. SETTING: General and paediatric intensive care units, Tartu University Hospitals and Institute of Anatomy, Tartu University. PATIENTS: 2 patients, who died of septic shock; 1 patient, who died of trauma. MEASUREMENTS AND RESULTS: Tissue samples of different organs (lungs, heart, spleen, pancreas, liver, adrenals, kidneys and brain) were studied for the presence of bacteria and for the local inflammatory reaction with light microscopy. Bacteria (cocci) were found in the capillaries and tissues of both septic shock patients, but not in the control patient. Capillary dilation, oedema, stasis and cell death, but no polymorphonuclear infiltration, were seen around the foci of bacterial invasion. CONCLUSIONS: Massive penetration of bacteria into all tissues without significant polymorphonuclear infiltration may take place in severe septic shock.