Reactive microglia in the developing brain

Summary Reactive microglia in the developing brain after stab wound was studied by morphological, cytochemical, and autoradiographic methods. Morphologically, early reactive cells are of the M cell type (Matthews 1974). They show an activated nucleus, cytoplasm rich in ribosomes with wide Golgi complex and variable numbers of lipid inclusions. Big clear vacuoles are found in many of these cells. Microtubules not associated with centrioles and filaments may or may not be present. Junctional complexes of the zonula or puncta adherentia types are occasionally found. Strong NADPH dehydrogenase, weak NADH dehydrogenase, strong ATPase, and strong acid phosphatase, in addition to nonspecific esterase activites were demonstrated in many reactive cells. Intravenous infusion of labelled bone marrow cells from a donor showed labelled macrophages and labelled perivascular cells at the site of injury. Intracerebral injection of a small dose of tritiated thymidine at the time of injury resulted in the appearance of labelled macrophages in the following days. These data suggest that many of the reactive cells have an exogenous, more probably monocytic, origin; but a certain amount of endogenous cells also act as macrophages in brain injuries.     

Presynaptic muscarinic receptor subtypes involved in the inhibition of acetylcholine and noradrenaline release in bovine cerebral arteries

Summary Experiments were performed in bovine cerebral arteries preincubated with [³H]-choline or [³H]-noradrenaline to analyze the presynaptic muscarinic receptors involved in inhibition of acetylcholine and noradrenaline release induced by electrical stimulation (4 Hz, 200 mA, 0.3 ms, 1 min). For this purpose, the actions of several muscarinic receptor antagonists on the ³H overflow and on the carbacol-induced inhibition of this overflow were assessed. The evoked [³H]-acetylcholine release and [³H]-noradrenaline release were markedly reduced by the presence of tetrodotoxin, Ca²⁺-free medium, and the inhibitor of both choline transport and choline acetyltransferase, AF64A. Chemical sympathetic denervation with 6-hydroxydopamine (6-OHDA) decreased the uptake of[³H]-noradrenaline, and AF64A reduced mainly the uptake of [³H]-choline, but also of [³H]-noradrenaline. Carbachol reduced the evoked [³H]-noradrenaline and [³H]-acetylcholine release; the IC₅₀ values were 0.37 and 0.43 mol/l, respectively.Atropine and 4-DAMP, but not AF DX 116, methoctramine or pirenzepine, increased the evoked [³H]-acetylcholine release. However, these muscarinic antagonists failed to modify the evoked [³H]-noradrenaline release. Carbachol inhibited the release of both acetylcholine and noradrenaline. The inhibition was blocked by the antagonists. The rank orders of potency (based on plC₅₀ values) were, in the case of [³H]-acetylcholine release, atropine > 4-DAMP >AF-DX 116 >- pirenzepine >- methoctramine, and, in the case of [³H]-noradrenaline release, atropine > 4-DAMP > AF-DX 116 >- methoctramine >-pirenzepine. These results suggest (1) that the prosynaptic receptors that modulate endogenous acetylcholine release are likely of the M₃ subtype, whilst those involved on the effect of the exogenous agonist Carbachol are of M₂ subtype, and (2) that those which inhibit noradrenaline release are probably a mixture of M₂ and M₃ subtypes as well. The autoinhibition of the acetylcholine release was funtionally active under our experimental conditions, while noradrenaline release does not appear to be modulated by muscarinic receptors in physiological conditions.Send offprint requests to G. Balfagón at the above address     

Immediate endoscopic diagnosis of upper gastrointestinal bleeding. Its accuracy and value in relation to associated pathology.

Two hundred sixty-two patients with active upper gastrointestinal (GI) bleeding underwent panendoscopy between July 1970 and March 1973. There was 100% accuracy of endoscopic diagnosis as to the anatomical site of bleeding; the etiopathologic definition was 94.7% accurate. The series was divided into two groups, 116 with "liver disease" and 146 with "no liver disease." There were 107 patients with varices: 21 fell into no liver disease (small varices) and 86 into liver disease (39 small and 47 large varices). All had associated gastritis. Three endoscopic bleeding patterns were identified in the liver disease group. Only 27% of the patients in the liver disease group with varices (cirrhotics) had frank variceal hemorrhage, whereas 57% bled from hemorrhagic gastritis. The diagnostic unit provided early diagnosis, meaningful therapy, organized data gathering, and rough estimates of ultimate prognosis.     

Camino intracranial pressure monitor: prospective study of accuracy and complications

OBJECTIVES: The fibreoptic device is a type of intracranial pressure monitor which seems to offer certain advantages over conventional monitoring systems. This study was undertaken to analyse the accuracy, drift characteristics, and complications of the Camino fibreoptic device. METHODS: One hundred and eight Camino intracranial pressure (ICP) devices, in their three modalities, were implanted during 1997. The most frequent indication for monitoring was severe head injury due to road traffic accidents. RESULTS: Sixty eight probe tips were cultured; 13.2% of the cases had a positive culture without clinical signs of infection, and 2.9% had a positive culture with clinical signs of ventriculitis. The most common isolated pathogen was Staphylococcus epidermidis. All patients were under cephalosporin prophylaxis during monitoring. Haemorrhage rate in patients without coagulation disorders was 2.1% and 15.3% in patients with coagulation abnormalities. Drift characteristics were studied in 56 cases; there was no drifting from the values expected according to the manufacturer's specifications in 34 probes. There was no relation between direction of the drift and duration of placement, nor between drift and time. CONCLUSIONS: Although the complication and drift rates were similar to those reported elsewhere, there was no correlation between the direction of the drift and long term monitoring despite the fact that some published papers refer to overestimation of values with time with this type of device.     

Systemic inflammatory response syndrome score at admission independently predicts mortality and length of stay in trauma patients

BACKGROUND: Recent studies have documented that the systemic inflammatory response syndrome (SIRS) score is a useful predictor of outcome in critical surgical illness. The duration and severity of SIRS are associated with posttrauma multiple organ dysfunction and mortality. We sought to determine whether the severity of SIRS at admission is an accurate predictor of mortality and length of stay (LOS) in trauma patients. METHODS: Prospective data of 4,887 trauma admissions to a Level I trauma center over a 18-month period (January 1997 to July 1998) were analyzed. Patients were stratified by age and Injury Severity Score (ISS), and a SIRS severity score (1 to 4) was calculated at admission (1 point for each component present: fever or hypothermia, tachypnea, tachycardia, and leukocytosis). The SIRS score was evaluated as an independent predictor of mortality and LOS by chi2 and multivariate logistic regression. RESULTS: Trauma patients (n = 4,887, 83% blunt injuries, 72% male) had the following characteristics: 73.1% were age 18 to 45 years, 17.5% were age 46 to 65 years, and 9.4% were age > or =66 years; 77.7% had ISS less than 15, 18.8% had ISS 16 to 29, and 3.5% had ISS greater than 29. Analysis of variance adjusting for age and ISS determined that SIRS score of 2 was a significant predictor of LOS. Furthermore, the relative risk of death increased significantly with SIRS score of 2 when age and ISS were held constant. CONCLUSION: Logistic regression analysis confirmed that a SIRS score of 2 was a significant independent predictor of increased mortality and LOS in trauma patients. These data suggest that admission SIRS scoring in trauma patients is a simple tool that may be used as a predictor of outcome and resource utilization.     

Novedades en estimulación cardiaca

This article contains a review of the current status of remote monitoring and follow-up involving cardiac pacing devices and of the latest developments in cardiac resynchronization therapy. In addition, the most important articles published in the last year are discussed.