Management of Gingival Recession by the Use of an Acellular Dermal Graft Material: A 12-Case Series

BACKGROUND

Different soft tissue defects can be treated by a variety of surgical procedures. Most of these techniques require the palatal area as a donor site. Recently, an acellular dermal graft has become available that can substitute for palatal donor tissue.

METHODS

This study describes the surgical technique for gingival augmentation and root coverage and the results of 12 clinical cases. A comparison between the three most popular mucogingival procedures for root coverage is also presented.

RESULTS

The results of the 12 patients and the 26 denuded surfaces have shown that we can obtain a mean root coverage of 74% with the acellular dermal graft. Thirteen out of the 26 denuded surfaces had complete root coverage. The average increase in keratinized tissue was 1.19 mm. It seems that the long-term results of the cases are stable.

CONCLUSION

The proposed technique of root coverage with an acellular dermal graft can be a good alternative to soft tissue grafts for root coverage, and it should be part of our periodontal plastic surgery armamentarium.

Long-term study of the frequency of Escherichia coli and Klebsiella pneumoniae isolates producing extended-spectrum β-lactamases

In total, 438 (1.7%) Escherichia coli and 125 (3.98%) Klebsiella pneumoniae isolates were found to be producers of extended-spectrum beta-lactamase (ESBL) during 1995-2003 in southern Spain. There was a significant increase in the frequency of ESBL-producing E. coli isolates, from < 0.36% before 1999 to 4.8% in 2003, while the frequency of ESBL-producing K. pneumoniae isolates decreased during the same period. The most common ESBLs detected in K. pneumoniae were SHV type, whereas both CTX-M and SHV types were detected in E. coli. In addition, E. coli isolates showed greater clonal diversity (84 distinct REP-PCR patterns, compared with five in K. pneumoniae), fewer enzymes per isolate, and a higher number of isolates recovered from outpatients. These differences may have implications for the control measures that should be used for these two microorganisms.

Nationwide study of Escherichia coli and Klebsiella pneumoniae producing extended-spectrum beta-lactamases in Spain

Clonal dissemination of extended-spectrum beta-lactamases (ESBL) in 170 Escherichia coli isolates and 70 Klebsiella pneumoniae isolates from a nationwide study of 40 Spanish centers in 2000 was not observed in most centers. The most prevalent ESBL were CTX-M-9 (27.3%), SHV-12 (23.9%), and CTX-M-14 (20.5%) for E. coli and TEM-3 (16.7%) and TEM-4 (25%) for K. pneumoniae. A new ESBL, TEM-133, with mutations L21F, E104K, and R164S, was identified.

Ethanolamine kinase controls neuroblast divisions in Drosophila mushroom bodies

The Drosophila mushroom bodies (MBs), paired brain structures composed of vertical and medial lobes, achieve their final organization at metamorphosis. The alpha lobe absent (ala) mutant randomly lacks either the vertical lobes or two of the median lobes. We characterize the ala axonal phenotype at the single-cell level, and show that the ala mutation affects Drosophila ethanolamine (Etn) kinase activity and induces Etn accumulation. Etn kinase is overexpressed in almost all cancer cells. We demonstrate that this enzymatic activity is required in MB neuroblasts to allow a rapid rate of cell division at metamorphosis, linking Etn kinase activity with mitotic progression. Tight control of the pace of neuroblast division is therefore crucial for completion of the developmental program in the adult brain.

Activity of cefepime and carbapenems in experimental pneumonia caused by porin-deficient Klebsiella pneumoniae producing FOX-5 beta-lactamase

The in-vivo activities of cefepime, imipenem and meropenem against the porin-deficient strain Klebsiella pneumoniae C2 and its derivative K. pneumoniae C2(pMG252) coding for the AmpC-type beta-lactamase FOX-5 were determined. Bactericidal activities were determined with the kill-curve method. A pneumonia model in guinea-pigs was developed, and Cmax, t(1/2) and DeltaT/MIC were calculated for the three agents tested. Animals were treated for 72 h with sterile saline (control group) or with cefepime, imipenem or meropenem (240 mg/kg/day, intramuscularly, three times daily). Bacterial counts in lungs (log10 CFU/g tissue) were determined by serial dilution. MICs (mg/L) of cefepime, imipenem and meropenem against K. pneumoniae C2/K. pneumoniae C2(pMG252), determined by macrodilution, were: 0.5/4, 0.5/0.5 and 0.25/0.5, respectively. Bacterial counts in the lungs of animals infected with K. pneumoniae C2 and treated with antimicrobial agents were always lower than in the control group (cefepime, 4.4 +/- 0.5; imipenem, 4.6 +/- 0.4; meropenem, 4.7 +/- 0.5; control group, 5.6 +/- 0.8; p <0.01). No significant differences were observed among the groups receiving therapy (p >0.05). Bacterial lung clearance was higher in treated animals than in control animals following infection with K. pneumoniae C2(pMG252) (cefepime, 4.5 +/- 0.4; imipenem, 4.0 +/- 0.3; meropenem, 4.6 +/- 0.4; control group, 6.1 +/- 0.6; p <0.01), with imipenem producing better clearance than either cefepime or meropenem (p <0.05). Thus, in the guinea-pig pneumonia model, cefepime, imipenem and meropenem were each effective against the porin-deficient K. pneumoniae strain C2 and its derivative expressing the plasmid-mediated AmpC type beta-lactamase FOX-5.

Conditional UAS-targeted repression in Drosophila

The Gal4–UAS enhancer trap system is useful for driving gene expression in various tissues. A new tool that extends Gal4 technology is described here. A fusion protein containing the Gal4 binding domain and the repression domain of the isolator suppressor of hairy wing was placed under the control of a heat shock-inducible promoter. The construct mediates the conditional repression of genes located downstream of a UAS sequence. The repressive effects of the chimeric protein on fasII gene expression were tested by western-blot analysis and in brain sections of adult Drosophila. Owing to the increasing number of Gal4 and UAS transgenic lines, this versatile system will facilitate the study of gene function.

Non-invasive interventions for improving well-being and quality of life in patients with lung cancer

BACKGROUND

Lung cancer is one of the leading causes of death globally. Despite advances in treatment, outlook for the majority of patients remains grim and most face a pessimistic outlook accompanied by sometimes devastating effects on emotional and psychological health. Although chemotherapy is accepted as an effective treatment for advanced lung cancer, the high prevalence of treatment-related side effects as well the symptoms of disease progression highlight the need for high quality palliative and supportive care to minimise symptom distress and to promote quality of life.

OBJECTIVES

To assess the effectiveness of non-invasive interventions delivered by healthcare professionals in improving symptoms, psychological functioning and quality of life in patients with lung cancer.

SEARCH STRATEGY

The Cochrane Central Register of Controlled Trials (The Cochrane Library Issue 4, 2003), MEDLINE (1966-March 2003), EMBASE (1974-March 2003), CINAHL (1982-September 2002), CancerLit (1975-October 2002), PsycINFO (1873-March 2003), reference lists of relevant articles and contact with authors.

SELECTION CRITERIA

Randomised or quasi-randomised clinical trials assessing the effects of non-invasive interventions in improving well-being and quality of life in patients diagnosed with lung cancer.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed relevant studies for inclusion. Data extraction and quality assessment of relevant studies was performed by one reviewer and checked by a second reviewer.

MAIN RESULTS

Nine trials were included and categorised into six groups. Two trials of a nursing intervention to manage breathlessness showed benefit on symptom experience, performance status and emotional functioning. Three trials assessed structured nursing programmes and found positive effects on delay in clinical deterioration, dependency and symptom distress, and improvements in emotional functioning and satisfaction with care. One trial assessing counselling showed benefit on some emotional components of the illness but findings were not conclusive. One trial assessing an exercise programme, found a beneficial effect on self-empowerment. One trial of nutritional interventions found positive effects for increasing energy intake, but no improvement in quality of life. One trial of reflexology showed some positive, but short-lasting effects on anxiety.

REVIEWERS' CONCLUSIONS

Nurse follow-up programmes and a nurse intervention to manage breathlessness may produce beneficial effects. Psychotherapeutic study indicates that counselling may help patients cope more effectively with emotional symptoms, but the evidence is not conclusive. Findings from the included studies reinforce the necessity for increased training and education of healthcare professionals giving in these interventions. More research, of higher methodological quality is needed in this area to explore possible underlying explanatory mechanisms.

Antimicrobial susceptibility and mechanisms of resistance to quinolones and beta-lactams in Acinetobacter genospecies 3

Antimicrobial susceptibility was determined in 15 epidemiologically unrelated clinical isolates of Acinetobacter genospecies 3. Moreover, the mechanisms of resistance to some beta-lactam antibiotics may be associated with the presence of a chromosomal cephalosporinase, AmpC, and the resistance to quinolones related to mutations in the gyrA and parC genes.

Exclusive consolidated memory phases in Drosophila

Two types of consolidated memory have been described in Drosophila, anesthesia-resistant memory (ARM), a shorter-lived form, and stabilized long-term memory (LTM). Until now, it has been thought that ARM and LTM coexist. On the contrary, we show that LTM formation leads to the extinction of ARM. Flies devoid of mushroom body vertical lobes cannot form LTM, but spaced conditioning can still erase their ARM, resulting in a remarkable situation: The more these flies are trained, the less they remember. We propose that ARM acts as a gating mechanism that ensures that LTM is formed only after repetitive and spaced training.

Neuroanatomy: brain asymmetry and long-term memory

The asymmetrical positioning of neural structures on the left or right side of the brain in vertebrates and in invertebrates may be correlated with brain laterality, which is associated with cognitive skills. But until now this has not been illustrated experimentally. Here we describe an asymmetrically positioned brain structure in the fruitfly Drosophila and find that the small proportion of wild-type flies that have symmetrical brains with two such structures lack a normal long-term memory, although their short-term memory is intact. Our results indicate that brain asymmetry may be required for generating or retrieving long-term memory.

Cerebral fluid edema: an unusual complication of ventriculoperitoneal shunts

INTRODUCTION

A case of accumulation of CSF into the brain parenchyma simulating a brain tumor, secondary to an obstructed ventriculoperitoneal shunt, is presented. Until now, only seven cases of this rare complication have been described.

CASE REPORT

Magnetic resonance showed an expansive, low-density intracranial lesion on the right frontal and parietal lobe. This mass was biopsied, but no tumor was found and the diagnosis was brain edema.

CONCLUSION

The mistake in the diagnosis was due to the clinical symptoms and to the MR images.

Infections by Neisseria meningitidis serogroup X in Spain

We describe an atypical presentation of bacteremia caused by N. meningitidis serogroup X. By multilocus sequence typing the isolate was characterized to the sequence type 2139, which is not related with the clonal complex recently isolated in Africa. Since 1984, only six cases of serogroup X N. meningitidis infections have been diagnosed in Spain. Nevertheless, after the application of the conjugated vaccine, attention should be paid to the emergence of infections caused by unusual serogroups of N. meningitidis.

Induction of tyrosine kinase receptor b by retinoic acid allows brain-derived neurotrophic factor-induced amyloid precursor protein gene expression in human SH-SY5Y neuroblastoma cells

Retinoic acid (RA) is a potent regulator of morphogenesis, growth and cell differentiation. Incubation with RA causes arrest of proliferation and neurite extension in SH-SY5Y cells, a neuroblastoma cell line of human origin. In these cells, RA regulates the expression of the beta-amyloid precursor protein. The retinoid increases the levels of intracellular and secreted forms of APP (amyloid precursor protein), APP-mRNA levels and the activity of the APP promoter in transient transfection studies. These responses require long periods of exposition to the ligand, thus suggesting a nondirect effect of the RA receptors on the APP gene. Also in these cells, RA induces the expression of TrkB, the tyrosine kinase receptor for brain-derived neurotrophic factor (BDNF), and 4 days of pretreatment with retinoic acid confers BDNF responsiveness to the APP promoter.

Detection of the plasmid-mediated quinolone resistance determinant qnr among clinical isolates of Klebsiella pneumoniae producing AmpC-type beta-lactamase

OBJECTIVES

Plasmid pMG252 contains the qnr locus, which is responsible for low-level resistance to quinolones by protecting the DNA gyrase. pMG252 also encodes the AmpC-type beta-lactamase (pACBL), FOX-5. The aim of this study was to determine the prevalence of qnr in strains from different geographical locations in America and Europe.

METHODS

Four hundred and twenty-five (159 Klebsiella pneumoniae and 266 Escherichia coli) clinical isolates were studied. The detection of qnr was by PCR using specific primers for an internal fragment of 543 bp.

RESULTS

qnr was detected in three cefoxitin-resistant K. pneumoniae strains, which also produced a pACBL. None of the E. coli isolates tested contained qnr. The three qnr-positive K. pneumoniae came from the USA, and all transferred a conjugative plasmid coding for cefoxitin resistance to E. coli J53. qnr was also transferred by the same plasmid in two out of the three strains. The sequences of amplified qnr fragments from the three strains were identical to the qnr sequence from pMG252.

CONCLUSIONS

The qnr determinant is uncommon among clinical isolates of K. pneumoniae and E. coli, but its identification in three pACBL+ K. pneumoniae from the USA indicates the emergence of this quinolone resistance mechanism.

Accumulation and activity of cethromycin (ABT-773) within human polymorphonuclear leucocytes

OBJECTIVES

To evaluate the penetration of ketolide cethromycin (ABT-773) into human polymorphonuclear leucocytes (PMNs) and its intracellular activity.

METHODS

The uptake of radiolabelled cethromycin by PMNs was determined by a velocity gradient centrifugation technique. The activity of cethromycin against intracellular Staphylococcus aureus ATCC 25923 in PMNs was also evaluated.

RESULTS

The cellular to extracellular concentration (C/E) ratio for cethromycin was >200 at an extracellular concentration of 2 mg/L. The uptake of cethromycin into PMNs was rapid and saturable. Cethromycin was slowly released from the loaded PMNs (cell associated drug>50% after 2 h of incubation). Intracellular penetration was significantly affected by the environmental temperature (C/E ratio at 4 degrees C and 37 degrees C: 13 +/- 6 and 226 +/- 31, respectively; P < 0.05), by cell viability (C/E ratio for dead and viable cells: 100 +/- 38 and 226 +/- 31, respectively; P < 0.05), by pH (C/E ratio was significantly increased at basic pH) and by the metabolic inhibitors 2,4-dinitrophenol and carbonyl cyanide m-chlorophenylhydrazone. The intracellular accumulation of cethromycin also decreased significantly when cells were activated with phorbol myristate acetate or opsonized zymosan. These data indicate that a potentially active mechanism could be involved in the uptake of cethromycin by PMNs. At high extracellular concentrations of 5 and 10 mg/L, cethromycin showed significant intracellular activity against S. aureus.

CONCLUSIONS

Cethromycin achieves high intracellular concentrations within human PMNs, remaining active intracellularly.

[In vitro activity of azithromycin against clinical isolates of Acinetobacter baumannii]

The activity of azithromycin against 225 clinical strains of Acinetobacter baumannii isolated consecutively from 26 Spanish hospitals in November 2000 was studied. The MICs of azithromycin were determined by microdilution, according to the NCCLS guidelines. The bactericidal activity of azithromycin against 15 clonally unrelated A. baumannii strains with different antimicrobial susceptibility patterns was tested using the subculture method. The killing-curves method was also performed against five strains with different susceptibility to azithromycin. The MIC(50) and MIC(90) of azithromycin were 32 and 64 mg/l, respectively. Moderate bactericidal activity was observed in 14 out of the 15 strains evaluated by the subculture method (MBCs from 1 to 4 dilution steps higher than the MICs) and by the killing-curve method. For three strains the number of CFU/ml was reduced 1 to 1.4 log by concentrations of azithromycin equivalent to 1 and 4 times their MICs. lt is concluded that azithromycin has moderate bactericidal activity against the strains of A. baumannii evaluated.

Evaluation of the WIDER I system for antimicrobial susceptibility testing of clinical isolates of Haemophilus influenzae and Streptococcus pneumoniae

The aim of this study was to evaluate the WIDER I system for susceptibility testing of Haemophilus influenzae and Streptococcus pneumoniae. MICs of 12 antimicrobials against 42 H. influenzae and 58 S. pneumoniae strains were determined using 1W MIC panels and compared with those obtained by microdilution. Overall essential agreements were >99%. Very major errors were not detected. Major errors occurred with ampicillin (1.7% H. influenzae). Minor errors were 2.3% (amoxicillin-clavulanate, cefuroxime, chloramphenicol), 7.1% (ampicillin) and 16.7% (clarithromycin) for H. influenzae, and 1.7% (chloramphenicol, erythromycin, meropenem), 3.4% (amoxicillin-clavulanate, cefuroxime, tetracycline) and 8.6% (levofloxacin) for S. pneumoniae. The WIDER I system is a reliable method for susceptibility testing of H. influenzae and S. pneumoniae.

Clinical efficacy and safety of a depigmented and glutaraldehyde polymerized therapeutic vaccine of Parietaria judaica

BACKGROUND

The inhalation of Parietaria judaica pollen is a common cause of allergic respiratory diseases in the Mediterranean area. The objective of this study was to investigate the safety and clinical efficacy of a chemically modified (depigmented and glutaraldehyde-polymerized) vaccine of Parietaria judaica.

METHODS AND RESULTS

Thirty patients with a well-documented clinical history of seasonal rhinitis and clinical sensitivity to Parietaria judaica pollen were included in a randomized trial during 12 months. The study was conducted following good clinical practices and appropriate consent forms were signed. Patients were divided into 2 groups of 15 individuals; group A received the modified extract and group C did not receive specific immunotherapy. Any adverse event was recorded to assess safety. Symptom scores, symptomatic medication use and the results of specific nasal challenges (before and after 12 months of treatment) were recorded to evaluate clinical efficacy. The treatment schedule consisted of an incremental phase of 5 injections and a maintenance dosage of 0.5 ml per month. Each patient received 14 injections during this period. All the patients completed the trial and no adverse reactions related to immunotherapy were recorded. A significant difference (p < 0.001) in symptom scores and overall use of symptomatic medication was observed between the two groups, being both scores lower in group A. No significant differences in nasal sensitivity existed before treatment among the 2 groups. However, after 12 months, a significant difference (p < 0.05) was observed only in group A patients, who showed a significant improvement in specific nasal challenges.

CONCLUSIONS

Immunotherapy with depigmented and glutaraldehyde-polymerized extract of Parietaria judaica pollen is safe and effective to treat patients with allergic rhinitis and clinical sensitivity to this pollen.

Evidence of Wallerian degeneration in normal appearing white matter in the early stages of relapsing-remitting multiple sclerosis: a HMRS study

OBJECTIVE

Wallerian degeneration in normal appearing white matter in early relapsing-remitting multiple sclerosis (RRMS), and its correlation with the number of relapses and disease duration. Background Recent pathological studies have demonstrated Wallerian degeneration in normal appearing white matter (NAWM) in multiple sclerosis (MS), in established RRMS, and in chronic MS. However, the presence of Wallerian degeneration early in the disease and its correlation with relapse and with disease duration has not been studied.

METHODS

We performed proton magnetic resonance spectroscopic imaging in 21 MS patients, and 4 healthy controls, age and gender matched, aged under 45 years, with a maximum of 4 years since first bout, and an EDSS score of less than 3.0. N-acetyl-aspartate (NAA) (an index of axonal integrity) was measured in the NAWM from the pons and the cerebellar peduncles.

RESULTS

We observed that the NAA levels were abnormally low in the NAWM in the early RRMS patients (p = 0.04, Student's t-test). The decrease in the NAA concentration correlated with disease duration in the two areas studied (p = 0.03 for pons and p = 0.04 for cerebellar peduncle); and with the number of previous relapses (Pearson's correlation = -0.582, p < 0.002).

CONCLUSION

Wallerian degeneration measured by the NAA concentration at pons and cerebellar peduncles is present early in the disease and correlates with the number of relapses and disease duration.

Pathogenesis of catheter-related infections: lessons for new designs

In the last decade, two main strategies have been employed in the prevention of catheter-related infections: the creation of anti-adhesive biomaterials using physicochemical methods, and the incorporation of antimicrobial or antiseptic agents into current polymer biomaterials. There has been limited success with the first approach. Intravascular catheters and cuffs with an antimicrobial coating have been developed in recent years. Nevertheless, preventive strategies should avoid the use of therapeutic antibiotics. Exposure to antimicrobial agents could favor the development of resistance or the expression of genes responsible for biofilm formation. The use of these catheters should be restricted to situations where the rate of infection is high despite adherence to other strategies that do not incorporate antimicrobial agents. Better knowledge of the pathogenesis of catheter-related infections will facilitate the design of new devices that avoid the use of antimicrobial agents and decrease the risk of associated bloodstream infections. This could include the use of 'biospecific polymers' coated with anti-adhesive molecules or the use of agents which might block the expression of genes controlling biofilm formation for the most prevalent pathogens.

High clinical inflammatory activity prior to the development of secondary progression: a prospective 5-year follow-up study

OBJECTIVE

To study if there are different patterns of clinical activity--measured by the annual exacerbation rate (AER)--among relapsing-remitting multiple sderosis (RRMS), "early" secondary multiple sclerosis (SPMS) and "late" SPMS.

METHODS

A prospective 5-year follow-up study in 80 MS patients has been carried out, calculating the AER and the mean expanded disability status scale (EDSS) change rate (MCR).

RESULTS

A significant difference on the AER, among RRMS, early SPMS and late SPMS, has been found.

CONCLUSIONS

The SPMS has a high clinical inflammatory activity before and during its transformation from a RRMS.

Differences between two new quinolones (gemifloxacin and trovafloxacin) and ciprofloxacin in their concentration-dependent killing of Streptococcus pneumoniae

BACKGROUND

Ciprofloxacin resistance influences the in vitro effect of new quinolones on Streptococcus pneumoniae.

METHODS

The early (over 3 h) in vitro bactericidal activity of gemifloxacin, trovafloxacin and ciprofloxacin was explored by time-kill tests against two ciprofloxacin-susceptible (MIC = 0.5 and 1 microg/ml) and two ciprofloxacin-resistant (MIC = 16 microg/ml) S. pneumoniae strains.

RESULTS

At subinhibitory concentrations (0.5 x MIC) and inhibitory concentrations (1 x MIC), only gemifloxacin exhibited significant bactericidal activity with, respectively, approximately 85 and approximately 95% decrease in the initial inoculum of the two ciprofloxacin-resistant strains. At concentrations similar to peak serum concentrations (1.5, 3 and 2.5 microg/ml for gemifloxacin, trovafloxacin and ciprofloxacin, respectively) after standard doses, only gemifloxacin exhibited an approximately 99.9% (3 log(10)) reduction in the initial inoculum for the four strains tested, regardless of their susceptibility to ciprofloxacin. No bactericidal activity was exhibited for the other two quinolones against the ciprofloxacin-resistant strains.

CONCLUSIONS

Gemifloxacin offers high early bactericidal activity at concentrations similar to peak and trough levels, theoretically preventing regrowth over the dosing interval, and thus dealing with the problem of ciprofloxacin resistance in S. pneumoniae.

Localization of long-term memory within the Drosophila mushroom body

The mushroom bodies, substructures of the Drosophila brain, are involved in olfactory learning and short-term memory, but their role in long-term memory is unknown. Here we show that the alpha-lobes-absent (ala) mutant lacks either the two vertical lobes of the mushroom body or two of the three median lobes which contain branches of vertical lobe neurons. This unique phenotype allows analysis of mushroom body function. Long-term memory required the presence of the vertical lobes but not the median lobes. Short-term memory was normal in flies without either vertical lobes or the two median lobes studied.

Brain-derived neurotrophic factor stimulates beta-amyloid gene promoter activity by a Ras-dependent/AP-1-independent mechanism in SH-SY5Y neuroblastoma cells

The beta-amyloid peptide, the major component of Alzheimer-associated plaques, derives from a larger beta-amyloid precursor protein (APP), that is expressed in both neural and non-neural cells. Overexpression of APP actively contributes to the development of senile plaques and is considered a risk factor for the disease. APP expression is regulated by a variety of cellular mediators, among them ligands of tyrosine kinase receptors. In this study, we present evidence that brain-derived neurotrophic factor (BDNF) modulates, in a dose- and time-dependent fashion, APP promoter activity in SH-SY5Y neuroblastoma cells transiently expressing the receptor TrkB. The APP promoter contains two potential AP-1 sites, and we examined whether or not protein kinase C (PKC) and the AP-1 sites of the promoter mediate the BDNF-induced stimulation of APP. Stimulation of APP promoter activity by BDNF was not affected by the PKC inhibitor bisindolylmaleimide, or by dominant negative mutants of the AP-1 components Fos and Jun, which, however, blocked the response to phorbol esters. These results suggest that activation of the APP promoter by BDNF is largely independent of PKC and AP-1. In contrast, activated Ras increased APP promoter activity in SH-SY5Y cells, and a dominant negative mutant of Ras abolished BDNF-mediated promoter stimulation. Taken together, our results suggest a mechanism that involves activation of the Ras/MAP kinase signaling pathway, and phosphorylation of as yet unidentified effectors which in turn can activate response elements within the APP promoter.

Glutamine potentiates TNF-alpha-induced tumor cytotoxicity

L-glutamine (Gln) sensitizes tumor cells to tumor necrosis factor (TNF)-alpha-induced cytotoxicity. The type and mechanism of cell death induced by TNF-alpha was studied in Ehrlich ascites tumor (EAT)-bearing mice fed a Gln-enriched diet (GED; where 30% of the total dietary nitrogen was from Gln). A high rate of Gln oxidation promotes a selective depletion of mitochondrial glutathione (mtGSH) content to approximately 58% of the level found in tumor mitochondria of mice fed a nutritionally complete elemental diet (standard diet, SD). The mechanism of mtGSH depletion involves a glutamate-induced inhibition of GSH transport from the cytosol into mitochondria. The increase in reactive oxygen intermediates (ROIs) production induced by TNF-alpha further depletes mtGSH to approximately 35% of control values, which associates with a decrease in the mitochondrial transmembrane potential (MMP), and elicits mitochondrial membrane permeabilization and release of cytochrome c. Mitochondrial membrane permeabilization was also found in intact tumor cells cultured with a Gln-enriched medium under conditions of buthionine sulfoximine (BSO)-induced selective GSH synthesis inhibition. Enforced expression of the bcl-2 gene in tumor cells could not avoid the glutamine- and TNF-alpha-induced cell death under conditions of mtGSH depletion. However, addition of GSH ester, which delivers free intracellular GSH and increases mtGSH levels, preserved cell viability. These findings show that glutamine oxidation and TNF-alpha, by causing a change in the glutathione redox status within tumor mitochondria, activates the molecular mechanism of apoptotic cell death.

Nuclear hormone receptors and gene expression

The nuclear hormone receptor superfamily includes receptors for thyroid and steroid hormones, retinoids and vitamin D, as well as different "orphan" receptors of unknown ligand. Ligands for some of these receptors have been recently identified, showing that products of lipid metabolism such as fatty acids, prostaglandins, or cholesterol derivatives can regulate gene expression by binding to nuclear receptors. Nuclear receptors act as ligand-inducible transcription factors by directly interacting as monomers, homodimers, or heterodimers with the retinoid X receptor with DNA response elements of target genes, as well as by "cross-talking" to other signaling pathways. The effects of nuclear receptors on transcription are mediated through recruitment of coregulators. A subset of receptors binds corepressor factors and actively represses target gene expression in the absence of ligand. Corepressors are found within multicomponent complexes that contain histone deacetylase activity. Deacetylation leads to chromatin compactation and transcriptional repression. Upon ligand binding, the receptors undergo a conformational change that allows the recruitment of multiple coactivator complexes. Some of these proteins are chromatin remodeling factors or possess histone acetylase activity, whereas others may interact directly with the basic transcriptional machinery. Recruitment of coactivator complexes to the target promoter causes chromatin decompactation and transcriptional activation. The characterization of corepressor and coactivator complexes, in concert with the identification of the specific interaction motifs in the receptors, has demonstrated the existence of a general molecular mechanism by which different receptors elicit their transcriptional responses in target genes.

Nerve growth factor modulates the expression and secretion of beta-amyloid precursor protein through different mechanisms in PC12 cells

The beta-amyloid protein, component of the senile plaques found in Alzheimer brains is proteolytically derived from the beta-amyloid precursor protein (APP), a larger membrane-associated protein that is expressed in both neural and non-neural cells. Overexpression of APP might be one of the mechanisms that more directly contributes to the development of Alzheimer's disease. The APP gene expression is regulated by a number of cellular mediators including nerve growth factor (NGF) and other ligands of tyrosine kinase receptors. We have previously described that NGF increases APP mRNA levels in PC12 cells. However, the molecular mechanisms and the precise signalling pathways that mediate its regulation are not yet well understood. In the present study we present evidence that NGF, and to a lesser extent fibroblast growth factor and epidermal growth factor, stimulate APP promoter activity in PC12 cells. This induction is mediated by DNA sequences located between the nucleotides - 307 and - 15, and involves activation of the Ras-MAP kinase signalling pathway. In contrast, we have also found that NGF-induced secretion of soluble fragments of APP into the culture medium is mediated by a Ras independent mechanism.

Unusual changing CT and MR appearance of an epithelial intracranial cyst

INTRODUCTION

Epithelial cysts are infrequent intracranial lesions and may content cilia and mucosecretant cells that may be responsible for the protein concentration within the contents and the variable radiological appearance on CT and MRI.

METHODS AND PATIENTS

We present a case of an extraaxial epithelial cyst with changing CT and MR characteristics.

RESULTS

The appearance of our cyst on CT or MRI changed with size and morphology. When CT studies showed an hypodense cyst, the lesion was large but when an hyperdense mass was present, the lesion was smaller. In the later situation MRI showed hyperintensity on T1-weighted images and hypointensity on T2-weighted images and the protein concentration of the cystic contents was high.

CONCLUSIONS

We believe that a relatively high protein concentration in our cyst was the major factor for the high attenuation on CT and the hyperintensity or hypointensity on T1- and T2-weighted images, respectively. We believe than these atypical imaging findings were caused by changes in the protein concentration within the cyst.

Synthesis and structure-activity relationships of benzophenone hydrazone derivatives with insecticidal activity

A broad range of benzophenone hydrazone derivatives was prepared and tested against selected chewing insect pests, allowing the analysis of structure-activity relationships. Good activity was found only when the aromatic rings were substituted at the 4-positions with an halogen atom and a triflate or perhaloalkoxy group. In contrast, a number of substituents on the hydrazone part led to active compounds, the best results being achieved with acyl-type substituents. The excellent laboratory and greenhouse activity of the best representatives was confirmed in semi-field trials against Spodoptera littoralis.

[False resistance to imipenem in gram negative bacilli with and automatized system]

BACKGROUND

The aim of this study was to evaluate the reliability of MIC values of imipenem against gramnegative rods obtained with the automated system WalkAway-98 (MicroScan, Dade, USA).

MATERIAL AND METHODS

One-hundred and seventy three consecutive clinical isolates of Gram-negative rods for which the MIC of imipenem were > or = 4 mg/l (Urine-Combo 6I panels, U6I) or > or = 8 mg/l (Neg-Combo 6I panels, N6I) were evaluated, including 104 non-fermenting gram-negative rods (NFGNR) and 69 enterobacteria. Panels were inoculated and read according to manufacturer's instructions. Microdilution, according to NCCLS guidelines, was used as the method of reference. MIC of imipenem determined by WalllAway-96 and microdilution differing > or = 2 dilution steps from those obtained with mirodilution were considered as discrepant results. Discrepancies in clinical categories were also evaluated by calculating three types of errors: very major (false susceptibility), major (false resistance) and minor (either susceptible or resistant by one method and intermediate by the other one).

RESULTS

The percentages of discrepancies in the MIC of imipenem determined with U6I panels were 74% and 84% for NFGNR and enterobacteria, respectively. No very major errors were detected. Major errors were observed for 6% and 12% of the strains with U6I panels in NFGNR and enterobacteria, respectively, and in 12% (NFGNR) and 50% (enterobacteria) with N61 panels. With U61 panels minor errors were observed in 11% and 25% of NFGNR and enterobacteria, respectively, while with N61 panels minor error were observed in 39% and 45% of both groups, respectively.

CONCLUSIONS

MIC of imipenem > or = 4 mg/l obtained with the WalkAway-96 system against gramnegative rods, particularly in the case of enterobacteria, should be confirmed with a reference susceptibility method.

Mitochondrial glutathione depletion by glutamine in growing tumor cells

The effect of L-glutamine (Gln) on mitochondrial glutathione (mtGSH) levels in tumor cells was studied in vivo in Ehrlich ascites tumor (EAT)-bearing mice. Tumor growth was similar in mice fed a Gln-enriched diet (GED; where 30% of the total dietary nitrogen was from Gln) or a nutritionally complete elemental diet (SD). As compared with non-tumor-bearing mice, tumor growth caused a decrease of blood Gln levels in mice fed an SD but not in those fed a GED. Tumor cells in mice fed a GED showed higher glutaminase and lower Gln synthetase activities than did cells isolated from mice fed an SD. Cytosolic glutamate concentration was 2-fold higher in tumor cells from mice fed a GED ( approximately 4 mM) than in those fed an SD. This increase in glutamate content inhibited GSH uptake by tumor mitochondria and led to a selective depletion of mitochondrial GSH (mtGSH) content (not found in mitochondria of normal cells such as lymphocytes or hepatocytes) to approximately 57% of the level found in tumor mitochondria of mice fed an SD. In tumor cells of mice fed a GED, 6-diazo-5-norleucine- or L-glutamate-gamma-hydrazine-induced inhibition of glutaminase activity decreased cytosolic glutamate content and restored GSH uptake by mitochondria to the rate found in EAT cells of mice fed an SD. The partial loss of mtGSH elicited by Gln did not affect generation of reactive oxygen intermediates (ROIs) or mitochondrial functions (e.g., intracellular peroxide levels, O(2)(-)(*) generation, mitochondrial membrane potential, mitochondrial size, adenosine triphosphate and adenosine diphosphate contents, and oxygen consumption were found similar in tumor cells isolated from mice fed an SD or a GED); however, mitochondrial production ROIs upon TNF-alpha stimulation was increased. Our results demonstrate that glutamate derived from glutamine promotes an inhibition of GSH transport into mitochondria, which may render tumor cells more susceptible to oxidative stress-induced mediators.

Intracellular penetration and activity of gemifloxacin in human polymorphonuclear leukocytes

The intracellular penetration and activity of gemifloxacin in human polymorphonuclear leukocytes (PMN) were evaluated. Gemifloxacin reached intracellular concentrations eight times higher than extracellular concentrations. The uptake was rapid, reversible, and nonsaturable and was affected by environmental temperature, cell viability, and membrane stimuli. At therapeutic extracellular concentrations, gemifloxacin showed intracellular activity against Staphylococcus aureus.

Absence of maternal-fetal transmission of human immunodeficiency virus type 1 to second-trimester fetuses

OBJECTIVE

The aim of this study was to evaluate the contribution of in utero infection to the vertical transmission of human immunodeficiency virus type 1 during the second trimester.

STUDY DESIGN

We examined fetal tissues from 21 second-trimester prostaglandin-induced abortions among human immunodeficiency virus type 1-infected women and compared the fetal vertical transmission rates with those among children born to human immunodeficiency virus-seropositive women. The presence of human immunodeficiency virus type 1 nucleic acid sequences was investigated with two different highly sensitive polymerase chain reaction techniques in tissue samples from the fetal thymus, lung, and brain.

RESULTS

No human immunodeficiency virus type 1 deoxyribonucleic acid was detected in any of the samples.

CONCLUSION

The absence of human immunodeficiency virus type 1 in all fetuses in our study is compatible with a low rate of maternal-fetal transmission during the second trimester of pregnancy.

Activities of imipenem and cephalosporins against clonally related strains of Escherichia coli hyperproducing chromosomal beta-lactamase and showing altered porin profiles

Forty clonally related clinical isolates of Escherichia coli from hospitalized patients were resistant to cefoxitin (MICs, >256 microg/ml) and ceftazidime (MICs, 32 to 256 microg/ml) and were intermediate or resistant to cefotaxime (MICs, 16 to 128 microg/ml) but susceptible to both cefepime (MICs, 0.5 to 2 microg/ml) and imipenem (MICs, 0.125 to 0.25 microg/ml). Resistance to beta-lactams was related to high-level production of AmpC beta-lactamase and loss of OmpF porin.

Uptake and intracellular activity of ofloxacin isomers in human phagocytic and non-phagocytic cells

The penetration and intracellular activity of ofloxacin and its isomers (levofloxacin and D-ofloxacin) into human polymorphonuclear leucocytes (PMN), human peritoneal macrophages (PMphi) and tissue cultured epithelial cells (McCoy) were evaluated. The cellular to extracellular concentration (C/E) values of the three fluoroquinolones were higher than 3.6 and 2.6 in PMN and PMphi, respectively. The C/E ratios in McCoy cells were lower than those in PMN, but still higher than 2.0. The uptake of ofloxacin and its isomers was rapid, non-saturable and reversible. All quinolones (extracellular concentrations: 2, 5 and 10 mg/l) produced a significant reduction of viable intraphagocytic Staphylococcus aureus in phagocytic cells. We concluded that ofloxacin and its isomers reach high intracellular concentrations in phagocytic and non phagocytic cells while remaining active in the former.

Relationship between outer membrane alterations and susceptibility to antimicrobial agents in isogenic strains of Klebsiella pneumoniae

The activities of beta-lactams, chloramphenicol, tetracycline, fluoroquinolones and aminoglycosides against Klebsiella pneumoniae C3 (O1:K66, producing porins OmpK35 and OmpK36) and a set of isogenic mutants derived from it lacking the O antigen of lipopolysaccharide (LPS), capsular K antigen, or one or both porins were determined. MICs remained within one dilution step in mutants deficient in antigen O, in capsule or in one of the two porins. No increases in the MICs of aminoglycosides, fluoroquinolones, tetracycline and chloramphenicol were observed for strains deficient in the two porins, but the MICs of ampicillin, cephalothin, cefoxitin, cefotaxime and ceftazidime for this type of mutant increased four- to >256-fold. The highest MICs of beta-lactams were obtained in a porin-deficient mutant expressing increased beta-lactamase activity. It is concluded that isolated outer membrane alterations in K. pneumoniae are not decisive factors in increasing resistance to antimicrobial agents, but porin loss co-operates with beta-actamase production to increase resistance to beta-lactams.

Mapping and fuzzy classification of macromolecular images using self-organizing neural networks

In this work the effectiveness of the fuzzy kohonen clustering network (FKCN) in the unsupervised classification of electron microscopic images of biological macromolecules is studied. The algorithm combines Kohonen's self-organizing feature maps (SOFM) and Fuzzy c-means (FCM) in order to obtain a powerful clustering technique with the best properties inherited from both. Exploratory data analysis using SOFM is also presented as a step previous to final clustering. Two different data sets obtained from the G40P helicase from B. Subtilis bacteriophage SPP1 have been used for testing the proposed method, one composed of 2458 rotational power spectra of individual images and the other composed by 338 images from the same macromolecule. Results of FKCN are compared with self-organizing feature maps (SOFM) and manual classification. Experimental results prove that this new technique is suitable for working with large, high-dimensional and noisy data sets and, thus, it is proposed to be used as a classification tool in electron microscopy.

In vitro adherence of Enterococcus faecalis and Enterococcus faecium to urinary catheters

The in vitro adherence of ten strains of Enterococcus faecalis and ten strains of Enterococcus faecium to siliconized latex urinary catheters and to silicone elastomer was evaluated. Bacterial suspensions (2.5x10(5) cfu/ml) in tryptic soy broth containing 0.5 cm segments from each type of catheter were incubated at 37 degrees C. At specified intervals, the segments were washed to remove nonadherent bacteria and sonicated for 1 min, and colony-forming units were quantified. Bacterial adherence occurred rapidly, reaching maximal peaks after 24 h of incubation. Enterococcus faecium adherence to both biomaterials was significantly lower than that of Enterococcus faecalis. No differences were observed between the two elastomers. Bacterial adherence was not related to bacterial surface hydrophobicity, hemolysin or gelatinase production.