Central-line-associated bloodstream infections, multi-drug-resistant bacteraemias and infection control interventions: a 6-year time-series analysis in a tertiary care hospital in Greece.

BACKGROUND: Central-line-associated bloodstream infections (CLABSIs) are serious healthcare-associated infections with substantial morbidity and hospital costs. AIM: To investigate the association between the incidence of CLABSIs, the implementation of specific infection control measures, and the incidence of multi-drug-resistant (MDR) bacteraemias in a tertiary care hospital in Greece from 2013 to 2018. METHODS: Analysis was applied for the following indices, calculated monthly: CLABSI rate; use of hand hygiene disinfectants; isolation rate of patients with MDR bacteria; and incidence of bacteraemias [total Gram-negative carbapenem-resistant Acinetobacter baumanii, carbapenem-resistant Pseudomonas aeruginosa and carbapenem-resistant Klebsiella pneumoniae; and Gram-positive meticillin-resistant Staphylococcus aureus and vancomycin-resistant enterococci]. FINDINGS: The total number of bacteraemias from carbapenem-resistant Gram-negative pathogens was significantly correlated with an increased CLABSI rate for all (total) hospital departments [incidence rate ratio (IRR) 1.17, 95% confidence interval (CI) 1.05-1.31, P=0.006] and the adult intensive care unit (ICU) (IRR 1.37, 95% CI 1.07-1.75, P=0.013). In the adult ICU, every increase in the incidence of each resistant Gram-negative pathogen was significantly correlated with a decreased CLABSI rate (carbapenem-resistant A. baumanii: IRR 0.59, 95% CI 0.39-0.90, P=0.015; carbapenem-resistant K. pneumoniae: IRR 0.48, 95% CI 0.25-0.94, P=0.031; carbapenem-resistant P. aeruginosa: IRR 0.54, 95% CI 0.33-0.89, P=0.015). The use of hand disinfectants was correlated with a decreased CLABSI rate 1-3 months before the application of this intervention for all (total) hospital departments (IRR 0.80, 95% CI 0.69-0.93, P=0.005), and for scrub disinfectants in the current month for the adult ICU (IRR 0.34, 95% CI 0.11-1.03, P=0.057). Isolation of patients with MDR pathogens was not associated with the incidence of CLABSIs. CONCLUSION: Hand hygiene was associated with a significant reduction in the incidence of CLABSIs at the study hospital. Time-series analysis is an important tool to evaluate infection control interventions.

Effectiveness of fissure sealants on initial caries lesions (ICDAS 1-3) of permanent molars: A 4-year follow-up.

AIM: The aim of the present prospective study was to evaluate the retention and effectiveness of two types of sealants (clear vs. opaque) on early pit and fissure occlusal non-cavitated ICDAS II #1-3, caries lesions of permanent posterior teeth of children. MATERIALS AND METHODS: Study Design: 6986 pit and fissure occlusal surfaces were randomly sealed with clear or opaque sealants out of which, 5828 sealants were placed on sound and 1158 on questionable surfaces, while 3508 were clear and 3478 opaque sealants. The mean age of the sample at initial sealant placement was 9.5 (±2.9) years and the follow-up time was 12-48 months. The median (IQR, range) follow-up time was 17.9 (8.7-28.6) months. Study inclusion and exclusion criteria applied to the combined database in order to select the study sample. Teethmate™ F-1 natural and opaque sealants (Kuraray, Hattersheim am Main, Germany) were applied following the standard procedure of preparation with moisture control kept by cotton rolls handled Dri-Angles" and a 30 seconds acid-etch with 37% ortho-phosphoric acid gel was used followed by 10 sec air-water spraying washing and polymerization for 20x2 sec. Sealants were applied on sound tooth surfaces (ICDAS #0) with no visible defects or on surfaces with early caries lesions (ICDAS #1-3), randomly and interchangeably on the upper or lower Jaw. Total retention was considered when all pits and fissures were completely sealed, while partial or complete loss was scored as one code, although was registered separately. STATISTICS: Separate analyses were performed for each type of failure (loss of sealant or restoration). Cumulative probabilities of failure over time after sealant placement, overall or by specific characteristics, were calculated using the Kaplan-Meier method. Association between these characteristics and the hazard of failure were investigated using appropriate Cox proportional hazard models. RESULTS: Sealed surfaces with ICDAS II # 1-3, showed 100% higher probability of having a restoration and 60% higher probability of sealant loss, with both differences being statistically significant (aHR=2.03, p=0.046), adjusted for age, sex, type of sealant and location of surface. Opaque sealants presented statistically significant (p 0.009) higher re-application rate, while fissures had 70% statistically significant (p<0.001) higher probability for resealing with time compared to pits, with gender not affecting sealant retention while the earlier a sealant was placed on children's teeth, the more probable it was to need resealing or restoration (p <0.012). CONCLUSIONS: The therapeutic use of sealants on occlusal surfaces of posterior permanent molars with early carious lesions (ICDAS II 1-3) is inferior compared to sound surfaces, showing higher sealant failures and restorations.

What do the changing patterns of comorbidity burden in people living with HIV mean for long-term management? Perspectives from European HIV cohorts.

Undoubtedly, comorbidities complicate long-term HIV management and have significant cost implications for healthcare systems. A better understanding of these comorbidities and underlying causes would allow for a more considered and proactive approach to the long-term management of HIV. This review examines cross-sectional analyses of six European cohort studies (Athens Multicenter AIDS Cohort Study, Aquitaine Cohort, EuroSIDA Cohort study, French claims EGB, German InGef Cohort and the Italian Cohort of Individuals, Naïve for Antiretrovirals), which included individuals with HIV followed over a certain period of time. Based on these cohorts, we examined how comorbidities have changed over time; how they compromise HIV management; and how much of a financial burden they impart. These data also provided a framework to explore the major issues of ageing and HIV and the practical implications of managing such issues in real-life practice.

Reference curves for CD4 T-cell count response to combination antiretroviral therapy in HIV-1-infected treatment-naïve patients.

OBJECTIVES: The aim of this work was to provide a reference for the CD4 T-cell count response in the early months after the initiation of combination antiretroviral therapy (cART) in HIV-1-infected patients. METHODS: All patients in the Collaboration of Observational HIV Epidemiological Research Europe (COHERE) cohort who were aged ≥ 18 years and started cART for the first time between 1 January 2005 and 1 January 2010 and who had at least one available measurement of CD4 count and a viral load ≤ 50 HIV-1 RNA copies/mL at 6 months (± 3 months) after cART initiation were included in the study. Unadjusted and adjusted references curves and predictions were obtained using quantile regressions. RESULTS: A total of 28 992 patients were included in the study. The median CD4 T-cell count at treatment initiation was 249 [interquartile range (IQR) 150, 336] cells/µL. The median observed CD4 counts at 6, 9 and 12 months were 382 (IQR 256, 515), 402 (IQR 274, 543) and 420 (IQR 293, 565) cells/µL. The two main factors explaining the variation of CD4 count at 6 months were AIDS stage and CD4 count at cART initiation. A CD4 count increase of ≥ 100 cells/mL is generally required in order that patients stay 'on track' (i.e. with a CD4 count at the same percentile as when they started), with slightly higher gains required for those starting with CD4 counts in the higher percentiles. Individual predictions adjusted for factors influencing CD4 count were more precise. CONCLUSIONS: Reference curves aid the evaluation of the immune response early after antiretroviral therapy initiation that leads to viral control.

The permanent deformation of the self-adjusting files when used in canals of extracted teeth.

AIM: To examine the permanent deformation of self-adjusting files (SAF) when used by endodontists with no previous experience with this system. METHODOLOGY: The canals of extracted human molars were initially prepared with glide path up to size 20 K-file. The operators were first instructed on the use of the SAF in simulated canals in plastic blocks then applied the SAF in natural root canals of extracted teeth. Every 4 min, each file was withdrawn from the canal and inspected for integrity. If intact, it was used in another canal for an additional 4 min and checked again. This was repeated until all 19 SAF files were deformed. The files were collected for inspection at ×50 magnification. All teeth were then examined radiographically for the presence of any metal fragments in the root canals. Permanent deformation was categorized according to the type and location occured. Three types were defined as follows: (i) detachment of one component of the file at one end while the component is retained (ii) detachment of a component at both ends and the component missing and (iii) permanent twisting of the component. Recordings were made and statistically analysed using McNemar's test. RESULTS: Mechanical failures on the 5-arch-side of SAF (odd side) were significantly more frequent in comparison with the even side (P = 0.039). Similarly, mechanical failures in arches on the odd side were also significantly more frequent compared with the even ones (P = 0.012) Longitudinal beams fractured significantly less often compared with arcs or struts (P < 0.001). In no case did complete file fracture occur, nor were metal fragments retained in the root canal. CONCLUSIONS: Deformation of SAF files occurred mainly as detachment of one of the arches or struts at connection points on the odd side of the file. In no case did its mechanical failure result in metal fragment retention in the root canal.

Effects of first antiretroviral regimen on lipid levels in HIV (+) individuals.

OBJECTIVE: To evaluate the long-term effects of different boosted protease inhibitors (bPIs) or non-nucleoside reverse transcriptase inhibitors (NNRTIs)-based antiretroviral regimens on lipid levels in HIV seropositive individuals who have not received lipid-lowering agents. METHODS: Data consisted of 595 patients participating in the population-based Athens Multicenter Cohort Study who were consistently followed up during 1996-2008. RESULTS: In naïve patients, lipid parameters increased sharply during the first 3 months of antiretroviral therapy and reached a plateau level approximately 6-9 months after therapy initiation. The plateau levels remained almost stable for up to 3.5 years. In general, bPIs exerted a more pronounced effect compared to NNRTIs. CONCLUSIONS: The administration of PI- or NNRTI-based regimens especially in naïve but also in unboosted PI experienced patients provoked a sharp increase in lipid levels that remained stable in higher levels for more than 3 years.

The optimal home blood pressure monitoring schedule based on the Didima outcome study.

This study investigated the optimal schedule for home blood pressure (HBP) monitoring that has the greatest prognostic ability and provides the most reliable assessment of HBP. The Didima study assessed the value of HBP (duplicate morning and evening measurements, 3 days) in predicting cardiovascular events in the general population (662 adults, 8.2+/-0.2 years follow-up). Criteria for the optimal monitoring schedule were stabilization of mean HBP, its variability (standard deviation (s.d.)) and hazard ratios (HRs) of cardiovascular events per 1 mm Hg HBP increase. By averaging more readings (1-12), there was a progressive decline in average HBP and its s.d. and increase in HR, with most of these benefits achieved on the second day (8 readings) and little additional benefit obtained on the third day (12 readings). The first day gave higher and more unstable HBP values (higher s.d.) with less prognostic ability (lower HR). The first HBP readings per occasion gave higher values but with similar prognostic ability as the second readings taken 1 min later. There was little difference in average HBP between morning and evening readings with no prognostic superiority of morning readings. In conclusion, by averaging more readings the average HBP and its variability are reduced and the prognostic ability improved. Any aspect of HBP monitoring (first or second readings, morning or evening) has similar prognostic ability. The first day gives higher and unstable values with lower prognostic ability and should be better discarded. These data validate the HBP monitoring schedule proposed by the European Society of Hypertension.

Frequency and distribution of root filled teeth and apical periodontitis in a Greek population.

AIM: To investigate the prevalence of root filled teeth and apical periodontitis (AP) in a Greek population. METHODOLOGY: A random sample of 320 patients who required full mouth periapical radiographic examination as a part of diagnostic and planning procedures were included. The age of the patients ranged from 16 to 77 years. A total of 7664 teeth were assessed and the frequency of root filled teeth and periapical status was recorded. Two observers evaluated the radiographs under standardized conditions. AP was defined as distinct periapical radiolucency or widening of the periodontal ligament space exceeding two times the normal width. Statistical evaluation of differences in proportions between groups was performed using random effects logistic regression models. RESULTS: The periapical status of 286 (3.7%) teeth was impossible to evaluate because of radiographic faults; these teeth were excluded from further analysis. A total of 1040 (13.6%) teeth had radiographic signs of AP and 680 (9.2%) teeth had been root filled. Of the root filled teeth, 408 (60.0%) had AP. There was no difference in the number of root filled teeth between males and females; the prevalence of root filled teeth increased with age. Significantly more molars (13.1%) and premolars (11.9%) than anterior teeth (5.8%) had been root filled (P < 0.001). The prevalence of AP was significantly higher (P < 0.001) in molars (23.9%) and premolars (14.0%) than anterior teeth (9.4%). CONCLUSIONS: The prevalence of AP and the frequency of root filled teeth with AP in this Greek population were higher than those found in many other European countries. The frequency of root filled teeth was comparable with findings in other epidemiological studies.

Comparison of evidence of treatment effects in randomized and nonrandomized studies.

CONTEXT: There is substantial debate about whether the results of nonrandomized studies are consistent with the results of randomized controlled trials on the same topic. OBJECTIVES: To compare results of randomized and nonrandomized studies that evaluated medical interventions and to examine characteristics that may explain discrepancies between randomized and nonrandomized studies. DATA SOURCES: MEDLINE (1966-March 2000), the Cochrane Library (Issue 3, 2000), and major journals were searched. STUDY SELECTION: Forty-five diverse topics were identified for which both randomized trials (n = 240) and nonrandomized studies (n = 168) had been performed and had been considered in meta-analyses of binary outcomes. DATA EXTRACTION: Data on events per patient in each study arm and design and characteristics of each study considered in each meta-analysis were extracted and synthesized separately for randomized and nonrandomized studies. DATA SYNTHESIS: Very good correlation was observed between the summary odds ratios of randomized and nonrandomized studies (r = 0.75; P<.001); however, nonrandomized studies tended to show larger treatment effects (28 vs 11; P =.009). Between-study heterogeneity was frequent among randomized trials alone (23%) and very frequent among nonrandomized studies alone (41%). The summary results of the 2 types of designs differed beyond chance in 7 cases (16%). Discrepancies beyond chance were less common when only prospective studies were considered (8%). Occasional differences in sample size and timing of publication were also noted between discrepant randomized and nonrandomized studies. In 28 cases (62%), the natural logarithm of the odds ratio differed by at least 50%, and in 15 cases (33%), the odds ratio varied at least 2-fold between nonrandomized studies and randomized trials. CONCLUSIONS: Despite good correlation between randomized trials and nonrandomized studies-in particular, prospective studies-discrepancies beyond chance do occur and differences in estimated magnitude of treatment effect are very common.

Alcohol exposure during the brain growth spurt promotes hippocampal seizures, rapid kindling, and spreading depression.

BACKGROUND: Epilepsy is a prominent sign of brain dysfunction and a cause of substantial disability in some children with fetal alcohol syndrome. The hippocampal formation is vulnerable to alcohol-induced pathologic changes and is the source of seizure activity in a variety of epileptic conditions. This study tests the hypothesis that developmental alcohol exposure facilitates epileptic activity and promotes kindling within hippocampal circuitry. METHODS: Rat pups received either a moderate dose (2.0 g/kg) or a high dose (3.75 g/kg) of alcohol via intragastric intubation over postnatal days 4 to 10. Intubated control and suckle control groups were also included. Upon reaching adulthood (postnatal days 85-100), the rats underwent electrophysiologic testing. A double-barrel potassium-sensitive microelectrode was placed into the right dentate gyrus stratum granulosum for the recording of extracellular field potential and extracellular potassium concentration. Stimuli were delivered via an electrode positioned in the CA3 subregion of the left hippocampus. To assess whether alcohol promotes hippocampal seizures and rapid kindling, the parameters of maximal dentate activation (MDA) were measured before, during, and after a series of stimulation-induced seizures. RESULTS: Developmental exposure to the high dose of alcohol permanently altered several parameters of MDA. Time to onset of MDA and stimulus threshold for afterdischarge production were both decreased, whereas the duration of the afterdischarge was increased. Although the moderate alcohol dose reduced time to onset of MDA, it did not affect any other MDA parameters. Over the course of the repeated induced seizures, spreading depression occurred more often and with fewer stimuli in the high-dose alcohol group than in any other group. The series of repeated electrographic seizures induced rapid kindling in all of the treatment groups. However, the kindling effect was enhanced in a dose-response manner by the previous alcohol exposures. CONCLUSIONS: These findings demonstrate that exposure to alcohol during brain development can permanently alter the physiology of the hippocampal formation, thus promoting epileptic activity, enhancing kindling, and facilitating spreading depression. The relative roles of alcohol intoxication and withdrawal in these abnormal physiologic responses remain unknown.

Transfection of C6 glioma cells with glia maturation factor upregulates brain-derived neurotrophic factor and nerve growth factor: trophic effects and protection against ethanol toxicity in cerebellar granule cells.

Glial cells play active roles in neuronal survival, as well as neuroprotection against toxic insult. Recent studies suggest that the brain protein glia maturation factor (GMF) is involved in intracellular signaling in glia. This study investigated whether or not GMF plays a role in the survival-promoting and neuroprotective functions of glia. C6 glioma cells were transfected in vitro with GMF utilizing an adenovirus vector. The transfected cells overexpressed GMF intracellularly, but did not secrete the protein. The conditioned medium (CM) was obtained from the GMF-transfected cells (CM-GMF) and tested on primary neuronal cultures, consisting of cerebellar granule cells (CGC). The CGC cultures were utilized because these cultures have a background level of cell death, and the survival-promoting, i.e. neurotrophic effect, of the CM could be tested. In addition, since CGC cultures are ethanol-sensitive (ethanol enhances neuronal death), the neuroprotective effect of the CM against ethanol-induced cell death was tested also. We demonstrated that the CM-GMF had an enhanced neurotrophic effect as well as an increased neuroprotective effect against ethanol-induced cell death compared to control CM obtained from untransfected C6 cells (CM-Mock) or CM obtained from cells transfected with an unrelated gene (CM-LacZ). Because neurotrophins have trophic and protective effects, we investigated whether GMF-transfection upregulated the expression of neurotrophins in C6 cells. RT-PCR verified that GMF-transfected C6 cells had increased mRNA levels for BDNF and NGF. Immunoblotting corroborated the RT-PCR results and indicated that CM-GMF contained greater concentrations of BDNF and NGF protein compared to CM-Mock and CM-LacZ. A soluble TrkB-IgG fusion protein, which selectively binds BDNF and prevents its binding to the neuronal TrkB receptor, eliminated the neurotrophic effect of CM-GMF; whereas anti-NGF antibody was ineffective in preventing this effect, suggesting that the neurotrophic effect was due to BDNF. On the other hand, both the TrkB-IgG fusion protein and anti-NGF reduced neuroprotection, suggesting that BDNF and NGF both contribute to the neuroprotective effect of CM-GMF. In conclusion, GMF upregulates the expression of BDNF and NGF in C6 cells, and these factors exert neurotrophic and neuroprotective functions on primary neurons.

Ethanol induces cell death and cell cycle delay in cultures of pheochromocytoma PC12 cells.

Animal models have clearly established that ethanol exposure can deplete neurons in the developing nervous system. However, the mechanism by which ethanol reduces cell number is unclear. In our study, cultures of pheochromocytoma cells, a neuronal-like cell line, were maintained in media, which supported cell proliferation. Although cell numbers continued to increase in the presence of ethanol, this increase was partially inhibited by ethanol exposure. This inhibitory effect was concentration and duration dependent. Cell proliferation was still partially inhibited after removal of ethanol, but this inhibition was temporary and disappeared after a 24-hr recovery period in ethanol-free conditions. Further study indicated that ethanol partially inhibited the increase in cell numbers by two mechanisms: (1) studies with vital stains indicated that ethanol induced cell death; (2) experiments using synchronized pheochromocytoma cell cultures showed that ethanol can induce cell cycle delay, thereby lengthening the doubling time of the cells. Analysis by flow cytometry indicated that with ethanol exposure, the cells accumulated in the G1 phase of the cell cycle. Our results suggest that in the developing nervous system, ethanol may limit the numbers of proliferating, neuronal precursor cells by two simultaneous mechanisms, cell death and cell cycle delay.

The nitric oxide-cyclic GMP pathway plays an essential role in both promoting cell survival of cerebellar granule cells in culture and protecting the cells against ethanol neurotoxicity.

NMDA has two beneficial effects on primary neuronal cultures of cerebellar granule cells (CGCs) established from 10-day-old rat pups. First, NMDA is neurotrophic and will enhance survival of CGCs in culture in the absence of ethanol. Second, ethanol exposure will induce cell death in CGC cultures, and NMDA can lessen this ethanol-induced cell loss, i.e., NMDA is neuroprotective. Because NMDA can stimulate production of nitric oxide (NO), which can in turn enhance synthesis of cyclic GMP, this study tested the hypothesis that the NO-cyclic GMP pathway is essential for NMDA-mediated neurotrophism and neuroprotection. Inhibiting the synthesis of NO with N(G)-nitro-L-arginine methyl ester eliminated both the NMDA-mediated neurotrophic and neuroprotective effects. Similarly, inhibiting production of cyclic GMP with the agent LY83583 also abolished these effects. The NO generator 2,2'-(hydroxynitrosohydrazono) bisethanamine produced neurotrophic and neuroprotective effects that were similar to those induced by NMDA. Also, 8-bromo-cyclic GMP produced neurotrophic and neuroprotective effects that were quite similar to the effects produced by NMDA. In conclusion, NMDA enhances survival of cerebellar granule cells and protects the cells against ethanol-induced cell death by a mechanism(s) that involves the NO-cyclic GMP pathway.

Nerve growth factor and basic fibroblast growth factor protect rat cerebellar granule cells in culture against ethanol-induced cell death.

Neuronal cell loss is one of the most debilitating effects of fetal ethanol exposure. Cultures of cerebellar granule cells are a useful model to investigate ethanol neurotoxicity, because ethanol depletes cell numbers in these cultures, which also occurs in vivo. The primary goal of the present study was to identify and characterize agents that can ameliorate the ethanol-induced cell death that occurs in this culture system. Growth factors, such as nerve growth factor (NGF), basic fibroblast growth factor (bFGF), epidermal growth factor (EGF), and insulin-like growth factor-I (IGF-I) can prevent neuronal degeneration after toxic insult in various experimental paradigms. These growth factors were investigated in the current study to determine whether or not they can mitigate ethanol-induced death of cerebellar granule cells in culture. Results indicate that NGF and bFGF significantly reduced the ethanol-induced cell loss. Both the NGF- and bFGF-mediated neuroprotection required protein and RNA synthesis, because actinomycin D (RNA synthesis inhibitor) and cycloheximide (protein synthesis inhibitor) blocked their neuroprotective effects. In addition to its neuroprotective effect, bFGF also had a neurotrophic effect and could enhance cell survival in the absence of ethanol exposure. NGF did not have a neurotrophic effect. Neither EGF nor IGF-I was neuroprotective, although the latter did have a substantial neurotrophic effect. In conclusion, bFGF and NGF have long been recognized for their role in enhancing neuronal cell survival and differentiation. This study suggests that these growth factors can also provide neuroprotection against ethanol-induced cell death.

Ethanol reduces expression of the nerve growth factor receptor, but not nerve growth factor protein levels in the neonatal rat cerebellum.

The cerebellum is especially vulnerable to ethanol's neurotoxic effects during development, and ethanol exposure during the brain growth spurt will deplete cerebellar neurons. The mechanisms undertying this neuronal cell loss remain elusive. Nerve growth factor (NGF) is a neurotrophin that promotes cell survival in various brain areas, and there is evidence that NGF may play a role in the developing cerebellum. This study examined whether ethanol exposure of the neonatal rat cerebellum altered the levels of either NGF or the expression of p75 and trkA, which are two components of the NGF receptor. Ethanol exposure had no effect on NGF levels in the neonatal cerebellum, as determined by an NGF-specific ELISA. Immunohistochemical labeling techniques indicated that both the p75 and trkA NGF receptors were expressed on Purkinje cell dendrites in the developing cerebellum, with posterior lobules expressing higher levels of p75 and trkA NGF receptor, compared with anterior lobules. Ethanol exposure of neonatal rats reduced the expression of both p75 and trkA NGF receptors on the Purkinje cell dendrites. These results suggest that ethanol could interfere with neurotrophic support of Purkinje cells by reducing the levels of available NGF receptor.

Ethanol exposure reduces the density of the low-affinity nerve growth factor receptor (p75) on pheochromocytoma (PC12) cells.

Although ethanol is detrimental to the developing nervous system, the mechanism(s) by which ethanol produces neuronal damage is (are) not clear. One potential mechanism is ethanol-induced inhibition of neurotrophic support. This study utilized an in vitro model, pheochromocytoma PC12 cells, to examine the effect of ethanol on the nerve growth factor (NGF) receptor. NGF binding studies indicated that ethanol exposure (400 mg/dl for 4 days) reduced the density of the low-affinity (p75) NGF receptor on PC12 cells, but had no effect on the density of the high-affinity NGF receptor. The equilibrium dissociation constants (Kd) for both the low-affinity and high-affinity NGF receptors were unaffected by ethanol. Low-affinity NGF binding is mediated by the p75 component of the NGF receptor. Quantification of p75 by immunoprecipitation revealed that ethanol reduced the level of p75 in PC12 cells. However, Northern analysis indicated that the p75 mRNA was not reduced by ethanol exposure, raising the possibilities that ethanol inhibited translation of p75 or incorporation of the p75 protein into the plasma membrane. This work is consistent with the hypothesis that ethanol's detrimental effects may be produced in part by inhibition of neurotrophic support at the receptor level.

Nerve growth factor synthesis by intestinal epithelial cells.

Nerve growth factor (NGF) exists in the gut of adult rats. The cells responsible for NGF synthesis in the gut remain unknown. IEC-6 and Caco-2 cells, established cell culture models of intestinal epithelial cells, were studied to determine whether intestinal epithelial cells, were studied to determine whether they synthesize and release NGF. Conditioned media from both IEC-6 and Caco-2 cells stimulated neurite outgrowth in both rat pheochromocytoma (PC-12) cells and sensory neurons derived from embryonic chick dorsal root ganglia (DRG). The addition of anti-NGF antibody blocked neurite outgrowth in PC-12 cells and partially blocked outgrowth in DRG cells. An NGF-enzyme-linked immunosorbant assay readily detected immunoreactive NGF in conditioned media from both cell lines, whereas cellular extracts from IEC-6, Caco-2, and isolated rat intestinal epithelial cells had low levels of immunoreactivity. Caco-2 monolayers primarily secreted NGF from the basolateral compartment, and interleukin-1 enhanced its secretion. IEC-6, Caco-2, and isolated rat intestinal epithelial cells expressed NGF mRNA as determined by reverse transcription polymerase chain reaction. These observations suggest that intestinal epithelial cells are capable of NGF synthesis.

NMDA prevents alcohol-induced neuronal cell death of cerebellar granule cells in culture.

Neuronal cell loss is one of the most debilitating effects of alcohol exposure during development of the nervous system. In this study, primary cultures of neuronal cells (cerebellar granule cells) were used to examine mechanisms of alcohol-induced neuronal cell death. Previously, we established that (Pantazis et al., Alcohol Clin Exp Res 17:1014-1021, 1993): (1) alcohol exposure caused neuronal cell death in cultures of cerebellar granule cells and this cell loss was both time-dependent and dose-dependent; and (2) the vulnerability of cerebellar granule cells to alcohol-induced loss changed with the length of time the cells were in culture before initiating alcohol exposure-that is, younger cultures (1 day in vitro) were much more susceptible to alcohol-induced neuronal cell death than older cultures (4 or 7 days in vitro). The primary goal of the present study was to examine the potential role of the NMDA receptor in alcohol-induced death of cerebellar granule cells in culture. Experiments were performed to test the hypothesis that the alcohol-induced death of cerebellar granule cells can be prevented or reduced by NMDA treatment. Our results indicate that stimulation of the NMDA receptor has a neuroprotective effect and can significantly reduce the alcohol-induced neuronal cell death of newly established cerebellar granule cell cultures. This neuroprotective effect of NMDA is blocked by 2-amino-5-phosphonovalerate, a competitive inhibitor of the NMDA receptor, confirming that this neuroprotective effect is mediated via the NMDA receptor. This is the first report that alcohol's neurotoxic effect can be ameliorated by activation of the NMDA receptor.

Fetal alcohol syndrome: the vulnerability of the developing brain and possible mechanisms of damage.

Fetal alcohol exposure has multiple deleterious effects on brain development, and represents a leading known cause of mental retardation. This review of the effects of alcohol exposure on the developing brain evaluates results from human, animal and in vitro studies, but focuses on key research issues, including possible mechanisms of damage. Factors that affect the risk and severity of fetal alcohol damage also are considered.

Vulnerability of cerebellar granule cells to alcohol-induced cell death diminishes with time in culture.

This study examined the effects of alcohol exposure on the viability of cerebellar granule cells in culture. Continuous alcohol exposure, starting 1 day after the cultures were established, significantly reduced granule cell numbers, even with a single day of exposure to an alcohol concentration as low as 100 mg/dl. The depletion of cerebellar granule cells by alcohol was concentration-dependent (greater loss of cells at higher alcohol concentrations) and duration-dependent (greater loss of cells at longer exposure durations). The loss of granule cells also depended on the number of days the granule cells were in culture before alcohol exposure. Alcohol was significantly more effective in reducing the cell numbers of newly established granule cell cultures (1 day in vitro) compared with older cultures (4 or 7 days in vitro). Cell cycle analysis established that the cerebellar granule cells did not proliferate in culture, indicating that alcohol exposure did not reduce cell numbers by interfering with cell proliferation in this system. Instead, alcohol-induced killing of the granule cells was the most likely mechanism to account for the depletion of granule cells in vitro. Granule cell cultures are a useful in vitro model system to study the cellular and molecular aspects of neuronal cell depletion associated with fetal alcohol exposure. The potential role of the N-methyl-D-aspartate receptor in this alcohol-induced neuronal cell death is discussed.