Intraoperative microbiological monitoring in abdominal aortic aneurysms in elective surgery. A review of the literature and the authors' personal experience]

Thirty-one patients, ranging in age from 57 to 78 years (mean 66), with the exclusion of cases with doubtful possible results, underwent abdominal aortic aneurysmectomy for asymptomatic AAA and had cultures from the aneurysmal wall and endovascular thrombus to identify possible microbiological source of future graft infection; 5 (16%) of 31 cultures yielded bacterial growth and the most common organism isolated was staphylococcus epidermidis. During an average follow-up of 15.4 months no graft infection was noted in patients with positive or negative aortic cultured. A literature review stresses the same disparity between positive cultures obtained at the aneurysmectomy and subsequent low graft-infection rate. It is concluded that the aneurysm wall itself does not represent an important source of early or late graft infection and it's suggested that the bacterial presence both in the wall and thrombus could be explained by an exogenous contamination at the operation time.     

Substance P receptors: Localization by light microscopic autoradiography in rat brain using [H]SP as the radioligand

Substance P (SP) is a putative neurotransmitter in both the peripheral and central nervous systems. In the present report we have used a modification of the Young and Kuhar technique to investigate some of the SP receptors binding properties and the distribution of SP receptors in rat brain. Tritiated SP ([³H]SP) adsorbed extensively to glass but this adsorption was greatly reduced by preincubating the slide-mounted tissue sections in a solution containing the cationic polymer polyethylenimine. [³H]SP was found to bind to rat tissue in a saturable fashion with a B_max of 14.7 fmol/mg tissue wet weight and a K_d of 1.1 nM. The rank order of potencies for displacing [³H]SP binding from rat tissue sections was SP > SP sulphoxide > DiMeC₇ > Eledoisin >0. SP(5–11) > SP(COOH) > SP(1–9) amide.Using autoradiography coupled with LKB tritium-sensitive Ultrofilm or the dry emulsion-coated coverslip technique the distribution of [³H]SP binding sites was found to be very dense within the olfactory bulb, amygdalo-hippocampal area and the nucleus of the solitary tract. Heavy concentrations of receptors were observed in the septum, diagonal band of Broca, striatum, subiculum, hypothalamus, locus coeruleus, parabrachial nucleus and lobule 9 and 10 of the cerebellum. Moderate to low concentrations of receptors were observed in the cerebral cortex, globus pallidus, raphe nuclei and the trigeminal nucleus. Very low densities were observed in most aspects of the dorsal thalamus, substantia nigra and cerebellum (other than lobule 9 and 10).Comparisons of the present data with SP peptide levels indicate that in some areas of the brain there is a rough correlation between peptide and receptor levels. However, in other brain areas (olfactory bulb, globus pallidus and substantia nigra) there is little obvious correlation between the two.     

Striatal increase of neurotrophic factors as a mechanism of nicotine protection in experimental parkinsonism

Summary The repeated finding of an apparent protective effect of cigarette smoking on the risk of Parkinson's disease is one of the few consistent results in the epidemiology of this disorder. Among the innumerous substances that originate from tobacco smoke, nicotine is by far the most widely studied, and the most likely candidate for a protective effect against neuronal degeneration in Parkinson's disease. Nicotine is a natural alkaloid that has considerable stimulatory effects on the central nervous system (CNS). Its effects on the CNS are mediated by the activation of neuronal heteromeric acetylcholine-gated ion channel receptors (nAChR, also termed nicotinic acetylcholine receptors). In the present study, we describe the neuroprotective effects of (–)nicotine in two animal models of parkinsonism: the diethyldithiocarbamate (DDC)-induced enhancement of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) toxicity in mice, and the methamphetamine-induced neurotoxicity in rats and mice. In parallel experiments, we found that (–)nicotine induces the basic fibroblast growth factor (FGF-2) and the brain-derived neurotrophic factor (BDNF) in rat striatum. As FGF-2 and BDNF have been reported to be neuroprotective for dopaminergic cells, our data indicate that the increase in neurotrophic factors is a possible mechanism by which (–)nicotine protects from experimental parkinsonisms. Moreover, they suggest that nAChR agonists could be of potential benefit in the progression of Parkinson's disease.     

Increased incidence of apparently life-threatening events due to supine position

Gastro-oesophageal reflux (GOR) has a high prevalence in infancy. The supine position is among numerous aggravating factors. The exact relationship between GOR and apparently life-threatening events (ALTE) is not clear, although it has been repeatedly investigated. In 1992 the worldwide Back to Sleep campaign was implemented, which had a dramatic effect on the incidence of sudden infant death syndrome (SIDS) with a drop of 50%. Although the vast majority of children now sleep on their back, the effect of this position on ALTE has not been studied. In this retrospective study, we aim to define the potential association between GOR and ALTE. We hypothesise that the incidence of ALTE has increased since the 1992 recommendation. No bias in the population's selection was introduced, as our centre is the only one for paediatric emergencies in the county. A total of 107 children presenting with ALTE were identified during the study period (1987-99). A pH study was performed in the 75 patients presenting with ALTE in the last 6 years of the study (1994-99). Neither morbidity nor mortality was noted in a long-term 4-year follow-up. Our present results show that the frequency of ALTE increased sevenfold (P < 0.005) between 1992 and 1999. The ALTE episodes took place significantly more often in the post-prandial period. The prevalence of GOR was much higher in patients presenting with ALTE (nearly 75%) when compared with the general population. Furthermore, on medical treatment for GOR, very few patients presented with a second episode of ALTE. Consequently it is thought that GOR and ALTE are linked and that ALTE patients would benefit from GOR treatment. The worldwide marked decrease in SIDS since the implementation of the supine position possibly masks the negative effect of an increase in ALTE.     

Correlates of bone quality in older persons

PURPOSE OF THE STUDY: In a population-based sample of older persons, we studied the relationship between tibial bone density and geometry and factors potentially affecting osteoporosis. METHODS: Of the 1260 participants aged 65 years or older eligible for the InCHIANTI study, 1155 received an interview and 915 (79.2%) had complete data on tibial QCT scans and other variables used in the analysis presented here. The final study population included 807 persons (372 men and 435 women, age range 65-96 years) after exclusion of participants affected by bone diseases or treated with drugs that interfere with bone metabolism. RESULTS: In both sexes, calf cross-sectional muscle area (CSMA) was significantly and independently associated with total bone cross-sectional area (tCSA) and cortical bone cross-sectional area (cCSA) but not with trabecular or cortical volumetric bone mineral density (vBMD). Bioavailable testosterone (Bio-T) was independently associated with both trabecular and cortical vBMD in both sexes. In women, independently of confounders, 25(OH)-vitamin D was positively associated with tCSA and cortical vBMD, while PTH was negatively associated with cortical vBMD. IL-1 beta was negatively correlated with cortical vBMD in women, while TNF-alpha was associated with enhanced bone geometrical adaptation in men. CONCLUSIONS: Physiological parameters that are generically considered risk factors for osteoporosis were associated with specific bone parameters assessed by tibial QCT. Factors known to be associated with increased bone reabsorption, such as 25(OH)-vitamin D, PTH and Bio-T, affected mainly volumetric BMD, while factors associated with bone mechanical stimulation, such as CSMA, affected primarily bone geometry. Our results also suggested that pro-inflammatory cytokines might be considered as markers of bone resorption.     

Binucleate classical mycoplasmas pathogenic for goats

The growth of three pathogenic goat mycoplasmas, strains Y, KH1 and Mycoplasma mycoides var. capri (PG3), was studied. They formed classical colonies on agar containing 1/500 thallium acetate. They were inactivated during storage at 2 to 4 C and by freezing and thawing but not by shaking. Only KH1 was killed by sonic treatment. Ultraviolet inactivation curves showed that their colony-forming units were single binucleate cells. Details of their growth curves are given. Filtration through 0.45- or 0.3-mum membrane filters removed up to 97% of the cells. Less than 0.003% passed 0.22-mum membranes. In electron micrographs, the cells were seen replicating by budding and most were 0.6 to 0.9 mum in diameter; but cells between 0.1 and 0.2 mum reproduced. They usually multiplied by producing one bud, a form of binary fission. However, two buds were produced by some synchronized cells, indicating that both nuclei had divided simultaneously to form progeny, an alternate method of multiplication.