[Bacterial meningitis in emergency medicine. Factors associated with delay of antimicrobial therapy]

BACKGROUND

Bacterial meningitis is a severe infection. Outcome might be improved if diagnosis and therapy are achieved promptly. We studied the time elapsed until antimicrobial therapy and analyzed factors associated to delay.

METHODS

We performed a retrospective study of bacterial meningitis diagnosed in a hospital emergency medicine department in two consecutive years. Dependent variable was time since admission to antimicrobial therapy; delay was defined as time to administration longer than 2 h. The relationship between clinical variables and delay was studied with bivariate analysis. Significative variables were included in a multivariate analysis using multiple logistic regression.

RESULTS

We studied 40 cases of bacterial meningitis (67.5% female, mean age 25.2 years). The mean time to antibiotic therapy was 127 min; in 16 patients (40%; 95% confidence interval: 25-56%) delay was 2 h or more. In bivariate analysis differences were observed for age (15.5 +/- 24.2 vs 39.7 +/- 28.7 years; p < 0.01), temperature (38.7 +/- 1 vs 38 +/- 1.1 degrees C; p < 0.05), mean blood pressure (77 +/- 14 vs 91 +/- 20 mmHg; p < 0.05), headache (29% vs 75%; p < 0.01), meningeal signs (63% vs 19%; p < 0.01), skin lesions (60% vs 13%; p < 0.01), "sick" presentation (67% vs 19%; p < 0.01), performance of CT scan (8% vs 38%; p < 0.05) and appropriateness of management (96% vs 44%; p < 0.001). In multivariate analysis only absence of skin lesions and inappropriate management remained significative. Mortality was higher when there was a delay of more than 2 h in antimicrobial therapy (25% vs 0%; p < 0.05).

CONCLUSIONS

Factors associated with delay of antimicrobial therapy were the absence of skin lesions and inappropriate management.

Induction of macrophage VEGF in response to oxidized LDL and VEGF accumulation in human atherosclerotic lesions

The interaction between macrophages and oxidatively modified low density lipoprotein (Ox-LDL) appears to play a central role in the development of atherosclerosis, not only through foam cell formation but also via the induction of numerous cytokines and growth factors. The current study demonstrated that Ox-LDL upregulated vascular endothelial growth factor (VEGF) mRNA expression in RAW 264 cells, a monocytic cell line, in a time- and concentration-dependent manner and that Ox-LDL stimulated VEGF protein secretion from the cells. Lysophosphatidylcholine, a component of Ox-LDL, also enhanced VEGF mRNA expression in RAW 264 cells and VEGF secretion from RAW 264 cells, with a maximal effect at a concentration of 10 micromol/L lysophosphatidylcholine. Immunohistochemical studies showed that human early atherosclerotic lesions exhibited intense VEGF immunoreactivity in subendothelial macrophage-rich regions of the thickened intima. In atherosclerotic plaques, VEGF staining was also observed in foam cell-rich regions adjacent to the lipid core or the neovascularized basal regions of plaque consisting predominantly of smooth muscle cells. High-power-field observation revealed that VEGF was localized in the extracellular space as well as at the macrophage cell surface. These observations suggest the possible involvement of Ox-LDL in the development of human atherosclerosis through VEGF induction in macrophages.

Inhibition of angiogenesis on glycated collagen lattices

Advanced glycation endproduct (AGE) accumulation in extracellular matrix proteins has been demonstrated in diabetic patients with a significant correlation with the severity of diabetic complications. AGE accumulation induces matrix protein cross-link formation, resulting in an increased stiffness of matrix fibres and the reduction of the susceptibility of matrix proteins to proteolytic degradation. We examined whether glycation-induced collagen cross-linking may affect vascular endothelial cell behaviours such as invasion, proliferation and differentiation, using the in vitro angiogenesis model of capillary-like structure formation in three-dimensional matrices of collagen type I. Endothelial cells cultured on collagen gel with angiogenic factors (the combination of fibroblast growth factor-2 and vascular endothelial growth factor) invaded the underlying collagen matrix, and organized capillary-like cord structures in the gel. We found that endothelial cell invasion into glycated collagen gel was significantly attenuated without any effect on proteinase activity including cell-associated plasminogen activator and matrix metalloproteinase in the conditioned medium. In addition, subsequent capillary-like cord formation was also inhibited in glycated collagen gel. In contrast, endothelial cell proliferation was enhanced on glycated collagen gel with or without angiogenic factors compared with control collagen gel. These results suggest that the structural alterations of extracellular matrix proteins through the glycation-induced cross-link formation affect the interaction between endothelial cell and extracellular matrix, resulting in the impairment of an adequate neovascularization in diabetic patients.

Angiogenic stimuli are essential for survival of vascular endothelial cells in three-dimensional collagen lattice

Cultured vascular endothelial cells derived from bovine aorta (BAECs) can survive and proliferate in the condition of two-dimensional monolayer culture in the presence of serum without any specific growth factors. When BAECs were embedded in collagen lattice, they underwent apoptotic death within 2 days unless the cultures were repeatedly supplied with angiogenic growth factor such as fibroblast growth factor-2 (FGF-2). Supplementation with FGF-2 induced endothelial cell differentiation, resulting in capillary-like tube formation inside collagen lattice. Following tube formation, withdrawal of FGF-2 induced disruption of the tube structures associated with the characteristic apoptotic cell death. These effects of FGF-2 were regulated by tyrosine phosphorylation, but not mediated through protein kinase C pathway. This model of endothelial cell apoptosis inside collagen lattice may represent in vivo endothelial cell-matrix interaction during angiogenesis process, indicating that apoptotic death of endothelial cells may regulate angiogenesis and the regression of vessels.

Up-regulation of vascular endothelial growth factor in response to glucose deprivation

Vascular endothelial growth factor (VEGF), also known as a vascular permeability factor (VPF), is an endothelial specific mitogen and is a potent inducer of angiogenesis. Recently it has been reported that hypoxia induces VEGF mRNA expression in various cells. Since both oxygen and glucose are required for efficient production of energy, we examined the effect of glucose deprivation on VEGF mRNA expression and VEGF protein production in U-937 (a human monocytic cell line) cells. Both the mRNA expression and secretion of VEGF increased after exposure to low glucose. Addition of L-glucose, the L-stereoisomer of D-glucose, did not prevent the up-regulation of VEGF expression. The conditioned medium from glucose-deprived cells, followed by supplementation with glucose, did not up-regulate VEGF mRNA expression in U-937 cells. The low glucose-induced VEGF mRNA expression returned to the control level after supplementation with D-glucose. Furthermore, oligomycin, a mitochondrial ATP synthase inhibitor, increased VEGF protein production. The results suggest that the up-regulation of VEGF mRNA in U-937 cells in response to glucose deprivation is not mediated by autocrine factors from the cells nor is the osmotic change of the medium mediated by the deficiency of glucose metabolism in the cells. Our results also suggest that the intracellular ATP depletion due to glucose deprivation may be one of the causes for increased VEGF mRNA expression. We speculate that local hypoglycemia may act as an essential trigger for angiogenesis through the VEGF gene expression.

Entamoeba histolytica contains a gene encoding a homologue to the 54 kDa subunit of the signal recognition particle

We have determined the nucleotide sequence and predicted amino acid sequence of the 54 kDa subunit of the signal recognition particle (SRP54) from the amitochondrial protist Entamoeba histolytica. The SRP54 gene was isolated from a genomic library using a polymerase chain reaction (PCR) probe. Nucleotide sequence analysis of a 2.3 kb fragment, derived from a 7 kb genomic clone, revealed an open reading frame encoding a protein of 487 amino acids (MW 53.8 kDa). The identities of the predicted amino acid sequence with its homologues from other species were between 24 and 47%. Functional domains previously defined for the SRP54-type proteins were present in the entamoebal sequence, such as the amino-terminal GTP binding domain (G domain) and the carboxy-terminal methionine rich domain (M domain). SRP54 mRNA contains an extra G residue at the 5' end, suggesting that capping of poly-A(+) transcripts is present in E. histolytica. Evolutionary analysis of the SRP54 based on phylogenetic inference placed the E. histolytica sequence as an early divergence of the eukaryotic tree. Although the function of the entamoebal homologue remains to be elucidated, the identification of the SRP54 gene constitutes the first evidence for SRP related proteins in protozoans.

[Acute myocardial infarction with normal coronary arteries as initial manifestation of polyarteritis nodosa. A case report]

A thirty four-year-old-white man in good health developed an acute anterior wall myocardial infarction (AMI), Killip II with normal coronary arteries. No thrombolytic therapy was given. Selective angiography revealed multiple aneurysms in mesenteric and renal arteries. The diagnosis of polyarteritis nodosa (PAN) was performed. AMI in PAN is secondary to arteritis with thrombosis, or to atherosclerosis due to steroid therapy. This case, having multiorgan vascular aneurysms involvement without previous cardiac symptomatology nor steroid therapy, presented as his first cardiac complication an AMI with normal coronary arteries probably due to selective arteritis.

The role of menopause in the development of chronic mountain sickness

The objective of this study was to investigate the role of menopause in the appearance of the physiopathological sequence that leads to chronic mountain sickness (CMS) in a high-altitude female population. The females studied are 30-54 yr old (n = 152) and have permanent residence in Cerro de Pasco (Pasco, Peru; 4,300 m). The sample was divided into postmenopausal and premenopausal groups for comparison. Blood oxygen saturation (SaO2), excessive erythrocytosis [EE, measured by the level of hematocrit (Het)], peak expiratory flow rates (PEFR), and a score that represents the main signs and symptoms of CMS (CMSscore) were measured. Postmenopausal women had higher Het (50.2 +/- 4.04 vs. 47.4 +/- 4.13%, P < 0.001), lower SaO2 (81.9 +/- 4.12 vs. 84.7 +/- 3.14%, P < 0.001) and PEFR values (489 +/- 101 vs. 534 +/- 90 l/min, P < 0.02), and slightly higher CMSscore (19.1 +/- 3.37 vs. 17.9 +/- 3.48, P < 0.06) than premenopausal women. The prevalence of women with EE (EE = Hct > 56%) was found to be 8.8%. Forty-five percent of the postmenopausal subjects presented a high CMSscore (> 21), whereas only 22% of the premenopausal subjects presented this high value (P < 0.02). We can therefore conclude that menopause may represent a contributing factor for the development of CMS.

[Epidemiology of neurosensorial deafness in the Foral Community of Navarra]

Congenital deafness is a relatively frequent disorder that shows a heterogeneous aetiology. Knowledge and the control of some risk factors have decreased the incidence of acquired deafness and increased the relative importance of genetic cause. In an attempt to investigate the clinical relevance of congenital deafness and the mechanisms of prevention in our population, a clinical and genetic study of cases with neurosensorial deafness born in Navarra between 1975 and 1990 was carried out. A total of eighty-one cases were identified, giving an incidence of 0.8 per thousand. Thirty per cent of the cases showed deafness associated with defects. Cause of deafness was identified in seventy per cent of the cases with whom a detailed clinical and genetic study could be performed (n=50). Genetic factors were responsible for the disorder in more than half of these cases. The most frequent hereditary factor was of the autosomic recessive type. This was associated with a more severe form of hearing loss.

MRI of congenital pituitary insufficiency

We compared 1.5 T magnetic resonance (MR) image findings in 193 patients with congenital pituitary insufficiency. One hundred and thirty nine of the MR studies were obtained in patients who had isolated growth hormone deficiency (GHD). Other fifty-four patients had multiple pituitary hormone deficiency (MPHD). On MR images, normal anterior and posterior lobes of the pituitary gland can be clearly differentiated because the posterior lobe has a characteristic high intensity on T1-weighted images. In fifty-four patients, the high-intensity of the posterior lobe was not seen, but a similar high signal intensity was observed at the proximal stump in fifty-one patients. This high-intensity area is the newly formed ectopic posterior lobe, which also secrets anti-diuretic hormone just as the posterior lobe would. MR imaging can demonstrate the transection of the pituitary stalk and the formation of the ectopic lobe, revealing to be a usefull diagnostic tool in the definition of the type of alteration in growth defects of endocrine origin.

Prenatal diagnosis of Friedreich ataxia: improved accuracy by using new genetic flanking markers

Friedreich ataxia is a neurodegerative disorder with autosomal recessive inheritance. Since the gene causing mutation has not yet been identified, prenatal, predictive, and carrier diagnoses are based on indirect haplotype analysis with closely linked markers. Until recently, only distal markers were available and their physical distance to the Friedreich ataxia (FRDA) gene remained elusive. The identification of close flanking markers that mark out the boundaries of the FRDA locus and reduce the critical genomic region which contains the gene allows for the first time misdiagnosis due to undetectable recombination to be avoided and diagnosis accuracy to be greatly improved. In this sense, we have verified a prenatal diagnosis in which the fetus was diagnosed as an unaffected carrier last year with a confidence of 95 per cent. By using the new flanking markers, the diagnosis improved and confidence reached almost 100 per cent.

[Acute myocardial infarct in young adults. A report of 142 cases]

We present 142 cases of myocardial infarction in the young (MIY) which correspond to 5.6% of a total of 2525 patients with MI hospitalized in the past 5 years at the Hospital de Especialidades del Centro Médico La Raza, IMSS. Among them, 124 (87%) were males and 18 (13%) females. The age varied from 25-40 years, average 35 years for both sexes. Occupational labor: 56 (39.5%) were workers, 27 (19%) officemen, 22 (15.5%) professionals, 20 (14%) taxi drivers, 15 (10.5%) merchants and 2 (1.5%) students. Personal cardiac history: 42 (30%) had history of angor pectoris and 5 (3.5%) of MI. Coronary risk factors: 106 patients (75%) had emotional stress due to type "A" personality, 101 (71%) cigarette smoking, 59 (42%) systemic arterial hypertension, 35 (25%) diabetes mellitus, 35 (25%) hyperlipidemias and 28 (20%) obesity. Among them, 34 (24%) had no risk factors. MI localization: 48 (34%) anteroseptal, 37 (26%) anterolateral, 36 (25%) posteroinferior and 21 (15%) inferior. Only in 83 cases coronary angiogram was performed, among them: 34 (41%) had disease of the left coronary artery and 18 (22%) of the right; 33 (40%) had one vessel, 15 (18%) 2 vessel and 4 (5%) 3 vessel disease. In 31 (37%) the coronary angiogram was normal.(ABSTRACT TRUNCATED AT 250 WORDS)

[Conduction disorders at multiple levels during the acute phase of a myocardial infarct: an electrophysiological study]

Forty patients with a diagnosis of acute myocardial infarction (anterior 24, and inferior 16) were studied. Of these patients, 37.5% manifested second and third degree atrioventricular (AV) block as a complication; another 30% showed complete right bundle branch and left anterior hemiblock. Right bundle branch and left posterior hemiblock were evidenced in 12.5% of the subjects. There was 20% with complete left bundle branch block. Electrophysiologic studies were performed in all patients to assess the site of block. A direct relation was found between the surface ECG and the His bundle electrogram studies in patients with an inferior myocardial infarction and AV block, both procedures located the conduction disturbances at the AV node (suprahisian block), in contrast to patients with anteroseptal myocardial infarction whose surface ECG only showed bundle branch block or fascicular block. The His bundle electrogram registered multiple levels of AV block, 70% with troncular and infrahisian block that gave way to sudden AV block. The mechanism responsible for this block was considered to be a functional longitudinal dissociation of conduction system due to an acute ischemic injury of the His bundle, more than a sudden and simultaneous failure of all the bundle branch of His. We conclude that electrophysiologic studies are a useful procedure for identification of a group of patients with multiple AV conduction disturbances that have a less favorable prognosis than those with only suprahisian level of block.

[Postangioplasty renal artery thrombosis treated intraluminally with thrombolysis. A case report]

The authors present the clinical case of a 31 year female with systemic vascular hypertension secondary to a 65 percent unilateral fibromuscular renal artery stenosis. The centellographic study demonstrated hypoperfusion on the right kidney and serious functional damage; the patient was subject to intraluminal renal angioplasty resulting in right renal arterial thrombosis, which was treated successfully with intra-arterial and intravenous streptokinase infusion. Following the thrombotic therapy, recanalization of the thrombosed artery and normal renal excretion of the contrast substance was observed.

[Circadian rhythm in myocardial infarct]

In order to determine if the beginning of the Myocardial Infarction (MI) is at random along the day or if it follows a circadian rhythm, we analyzed the clinical charts of 819 patients admitted to the Coronary Care Unite. Among them, 645 were male and 174 female. It was established that the beginning of the MI follows a circadian rhythm with maximal frequency between 8 and 9 a.m. and minimal at 0 hours (p greater than 0.01). This rhythm is sex independent. In patients younger than 45 years as well as those who received beta-block agents in less than 24 hours previous the MI no circadian rhythm was observed.