Differences of pathophysiology in experimental meningitis caused by three strains of Streptococcus pneumoniae.

Differences in cytochemical and pathophysiologic abnormalities in experimental meningitis caused by pneumococcal strains A, B, and C were determined. Strain C produced the most severe abnormalities of cerebrospinal fluid (CSF) concentrations of lactate (P less than .01), protein (P less than .02), and glucose (P less than .01), CSF white blood cell count (P less than .04), cerebral blood flow (P less than .02), and clinical signs (P less than .05). Brain edema occurred only with strains A anc C, with no association with disease severity; intracranial hypertension was also independent of disease severity. Strain B, not C, achieved the highest bacterial titers in the CSF (P less than .005). The widely different abilities of strains of Streptococcus pneumoniae to induce intracranial abnormalities suggest that virulence determinants affect not only evasion of defense during colonization and invasion, as shown in other models, but also determine the course of disease once infection has been established. Differences of cell-wall metabolism among pneumococcal strains may play a role in this latter phase of the development of meningitis.

[Serum erythropoietin levels: a new diagnostic tool?]. / Serumerythropoietinwerte: ein neues diagnostisches Hilfsmittel?

The development of highly specific antibodies against recombinant human erythropoietin (EPO) has recently made the accurate radioimmunological measurement of serum levels of this hormone possible. In this study we determined the serum-EPO levels in 100 healthy volunteers, in 54 patients suffering from polycythemia vera and in 51 patients with secondary polyglobulia. The mean levels for the healthy group were found to be 11.3 +/- 3.4 mU/ml in females and 8.0 +/- 3.2 mU/ml in males. Patients with polycythemia vera had serum-EPO levels of 4.3 mU/ml, while those with secondary polyglobulia had significantly higher levels averaging 30.3 mU/ml (p less than 0.0001). However, an overlapping of serum-EPO values in the range between 10 and 20 mU/ml occasionally occurs. Our results show that measurement of the serum-EPO level can be useful in the differential diagnosis of polyglobulias. Additionally, sequential EPO level measurements after phlebotomy and after hemorrhage show a pronounced increase in serum-EPO in secondary polyglobulia, while in polycythemia vera the level only increases slightly.

Brain edema and increased intracranial pressure in the pathophysiology of bacterial meningitis.

A number of advances in our understanding of the pathophysiology of bacterial meningitis have been made in recent years. In vivo studies have shown that bacterial cell wall fragments and endotoxins are highly active components, independent of the presence of viable bacteria in the subarachnoid space. Their presence in the cerebrospinal fluid is associated with the induction of inflammation and with the development of brain edema and increased intracranial pressure. Antimicrobial therapy may cause an additional increase of harmful bacterial products in the cerebrospinal fluid and thereby potentiate these pathophysiological alterations. These changes may contribute to the development of brain damage during meningitis. Some promising experimental work has been directed toward counteracting the above phenomena with non-steroidal or steroidal anti-inflammatory agents as well as with monoclonal antibodies. Although considerable advances have been made, further research needs to be done in these areas to improve the prognosis of bacterial meningitis.