Several putative neurotransmitters and metabolites were monitored simultaneously in the extracellular space of neostriatum, substantia nigra, and cortex and in subcutaneous tissue of the rat by in vivo microdialysis. Glutamate (Glu) and aspartate (Asp) were at submicromolar and y-aminobutyric acid (GABA) was at nanomolar concentrations in all brain regions. The highest concentration of dopamine (DA) was in the neostriatum. Dynorphin B (Dyn B) was in the picomolar range in all brain regions. Although no GABA, DA, or Dyn B could be detected in subcutaneous tissue, Glu and Asp levels werẽ 5 and coO.4 fiM, respectively. Lactate and pyruvate concentrations were cru200 and rmlO 1iM in all regions. The following criteria were applied to ascertain the neuronal origin of substances quantified by microdialysis: sensitivity to (a) Kdepolarization, (b) Na~channel blockade, (c) removal of extracellular Ca 2~,and (d) depletion of presynaptic vesicles by local administration of c~-latrotoxin. DA, Dyn B, and GABA largely satisfied all these criteria. In contrast, Glu and Asp levels were not greatly affected by Kdepolarization and were increased by perfusing with tetrodotoxin or with Ca2~-free medium, arguing against a neuronal origin. However, Glu and Asp, as well as DA and GABA, levels were decreased under both basal and K~-depolarizingconditions by ce-latrotoxin. Because the effect of Kdepolarization on Glu and Asp could be masked by reuptake into nerve terminals and glial cells, the reuptake blocker dihydrokainic acid (DHKA) or L-trans-pyrrolidine-2,4-dicarboxylic acid (PDC) was included in the microdialysis perfusion medium. The effect of K~depolarization on Glu and Asp levels was increased by DHKA, but GABA levels were also affected. In contrast, PDC increased only Glu levels. It is concluded that there is a pool of releasable Glu and Asp in the rat brain. However, extracellular levels of amino acids monitored by in vivo microdialysis reflect the balance between neuronal release and reuptake into surrounding nerve terminals and glial elements.
A 7-month outbreak of 15 cases of postpartum sepsis with group A haemolytic Streptococci (GAS) was stopped when a carrier was identified. Comparing delivery dates with duty rotas revealed that the carrier had been present during delivery in 13 of the 15 cases. The epidemic GAS type, T3-13-B3264, was found in a carbuncle in her groin and in atopic dermatitis lesions behind her ears and on her eyelids. Thus, it was not the microbiological screening of staff that helped detect the carrier. The outbreak went unnoticed for 6 months, as no 2 cases were diagnosed by the same physician and 5 cases were diagnosed by different general practitioners. The main risk factors for infection were presence of the carrier relative risk (relative risk RR 47.8, 95% confidence interval (CI) 10.9-209.5) and suturing of episiotomy (RR 11.0; 95% CI 2.6-47.9). We recommend that a thorough epidemiological investigation should be carried out in every single case of GAS postpartum infection. Despite initial intravenous treatment with penicillin, 8 patients experienced > 15 recurring postpartum GAS infections, such as endometritis, wound infection, tonsillitis, erysipelas and Brodie's abscess. Eradication of GAS should be confirmed after completion of treatment.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.