Recent evidence shows that lipid raft membrane domains modulate both cell survival and death. Here, we have found that the phosphatidylinositol-3-kinase (PI3K)/Akt signaling pathway is present in the lipid rafts of mantle cell lymphoma (MCL) cells, and this location seems to be critical for full activation and MCL cell survival. The antitumor lipids (ATLs) edelfosine and perifosine target rafts, and we found that ATLs exerted in vitro and in vivo antitumor activity against MCL cells by displacing Akt as well as key regulatory kinases p-PDK1 (phosphatidylinositol-dependent protein kinase 1), PI3K and mTOR (mammalian TOR) from lipid rafts. This raft reorganization led to Akt dephosphorylation, while proapoptotic Fas/CD95 death receptor was recruited into rafts. Raft integrity was critical for Ser473 Akt phosphorylation. ATL-induced apoptosis appeared to correlate with the basal Akt phosphorylation status in MCL cell lines and primary cultures, and could be potentiated by the PI3K inhibitor wortmannin, or inhibited by the Akt activator pervanadate. Classical Akt inhibitors induced apoptosis in MCL cells. Microenvironmental stimuli, such as CD40 ligation or stromal cell contact, did not prevent ATL-induced apoptosis in MCL cell lines and patient-derived cells. These results highlight the role of raft-mediated PI3K/Akt signaling in MCL cell survival and chemotherapy, thus becoming a new target for MCL treatment.
mantle cell lymphoma; lipid rafts; PI3K/Akt signaling; Akt phosphorylation; apoptosis; synthetic antitumor lipids
Past studies reported more widespread structural brain abnormalities in patients with left compared to right temporal lobe epilepsy (TLE), but the profile of these differences remain unknown. This study investigated the relationship between cortical thinning, white matter compromise, epilepsy variables, and the side of seizure onset, in patients with TLE.
We performed diffusion tensor imaging tractography and cortical thickness analyses of 18 patients with left TLE (LTLE), 18 patients with right TLE (RTLE), and 36 controls. We investigated the relationship between brain structural abnormalities, side of seizure onset, age of seizure onset, and disease duration.
TLE groups displayed cortical thinning and white matter compromise, predominately on the side ipsilateral to the seizure onset. Relative to RTLE, patients with LTLE showed more widespread abnormalities, particularly in white matter fiber tracts. Greater compromise in white matter integrity was associated with earlier age of seizure onset, while cortical thinning was marginally associated with disease duration.
These data support previous findings of LTLE showing greater structural compromise than RTLE, and suggest that mechanisms may not be uniform for gray and white matter compromise in patients with LTLE and RTLE. These results may indicate that LTLE is different than RTLE, possibly due to greater vulnerability of the left hemisphere to early injury and the progressive effects of seizures.
epilepsy; MRI; diffusion tensor imaging; cortical thickness
Background. It has been widely suggested that analyses considering multilocus effects would be crucial to characterize the relationship between gene variability and essential hypertension (EH). Objective. To test for the presence of multilocus effects between/among seven polymorphisms (six genes) on blood pressure-related traits in African-derived semi-isolated Brazilian populations (quilombos). Methods. Analyses were carried out using a family-based design in a sample of 652 participants (97 families). Seven variants were investigated: ACE (rs1799752), AGT (rs669), ADD2 (rs3755351), NOS3 (rs1799983), GNB3 (rs5441 and rs5443), and GRK4 (rs1801058). Sensitivity analyses were further performed under a case-control design with unrelated participants only. Results. None of the investigated variants were associated individually with both systolic and diastolic BP levels (SBP and DBP, respectively) or EH (as a binary outcome). Multifactor dimensionality reduction-based techniques revealed a marginal association of the combined effect of both GNB3 variants on DBP levels in a family-based design (P = 0.040), whereas a putative NOS3-GRK4 interaction also in relation to DBP levels was observed in the case-control design only (P = 0.004). Conclusion. Our results provide limited support for the hypothesis of multilocus effects between/among the studied variants on blood pressure in quilombos. Further larger studies are needed to validate our findings.
Neural circuits mediating repetition effect for semantically congruous words on functional MRI were investigated in seventeen normal elderly (mean age = 70). Participants determined if written words were semantically congruent (50% probability) with spoken statements. Subsequent cued-recall revealed robust explicit memory only for congruous items (83% versus 8% for incongruous). Event-related BOLD responses to New > Old congruous words were found in the left > right cingulate and fusiform gyri, left parahippocampal cortex, middle and inferior frontal gyri (IFG). A group with above-median subsequent recall had markedly more widespread BOLD responses than a Low-Recall subgroup, with larger responses in the left medial temporal lobe (LMTL), IFG, and bilateral cingulate gyri. The magnitude of LMTL activation (New–Old) correlated with subsequent cued-recall, while the spatial extent of LMTL activation (New > Old) correlated with recall and recognition. Both magnitude and spatial extent of left fusiform activation correlated with subsequent recall/recognition. A neural circuit of left-hemisphere brain regions, many identified as P600 generators by invasive electrophysiological studies, was activated by New > Old congruous words, likely mediating successful verbal encoding.
Aging; Memory; Neuroimaging; Learning; Semantic; Language; Medial temporal lobe; Fusiform gyrus
It has been widely reported a vascular and neurologic damage of the lumbar muscles produced in the classic posterior approach for lumbar spinal fusions. The purpose of this study is to demonstrate a better clinical and functional outcome in the postoperative and short term in patients undergoing minimal invasive surgery (“mini-open”) for this lumbar spinal arthrodesis. We designed a prospective study with a 30 individuals cohort randomized in two groups, depending on the approach performed to get a instrumented lumbar circumferential arthrodesis: “classic posterior” (CL group) or “mini-open” approach (MO group). Several clinical and functional parameters were assessed, including blood loss, postoperative pain, analgesic requirements and daily life activities during hospital stay and at the 3-month follow-up. Patients of the “mini-open approach” group had a significant lower blood loss and hospital stay during admission. They also had significant lower analgesic requirements and faster recovery of daily life activities (specially moderate efforts) when compared to the patients of the “classic posterior approach” group. No significant differences were found between two groups in surgery timing, X-rays exposure or sciatic postoperative pain. This study, inline with previous investigations, reinforces the concept of minimizing the muscular lumbar damage with a mini-open approach for a faster and better recovery of patients’ disability in the short term. Further investigations are necessary to confirm these findings in the long term, and to verify the achievement of a stable lumbar spinal fusion.
Mini-invasive; Surgery; Lumbar fusion; Discopathy; Arthrodesis
Testosterone has been proposed to have a dual effect, enhancing sexual traits while depressing parasite resistance in males. Here, we test this hypothesis in red deer, examining males from captive populations during the whole annual cycle and males from natural populations during the breeding season. We first explored the effects of body size, age and sampling date on testosterone to avoid confounding effects. Our results show that in captive populations seasonal changes in testosterone levels were mirrored by changes in testes size, and that during the rut there was a strong correlation between both. In natural populations, males with higher testosterone levels had larger testes, improved sperm quality, smaller burr diameter, stronger antlers, higher haematocrit levels, and increased nematode parasite load. By contrast, no significant relationship was found between testosterone and spleen size or tick parasite load. We conclude that testosterone (i) improves males' reproductive investment and physical stamina, (ii) improves antler strength but reduces burr diameter, and (iii) imposes a cost in terms of depressed parasite resistance.
immunocompetence handicap hypothesis; testosterone; antler; haematocrit; testes; sperm quality
Angiosarcomas are malignant neoplasias of rapid growth that develop from endothelial cells. They represent 2% of all sarcomas and only 1–4% are located in the aerodigestive tract. Since 1977, only 16 cases have been reported.
We present a 33-year-old male with spontaneous epistaxis that was refractory to cauterization. During physical examination, a smooth purplish tumor of 1.5 cm × 1.5 cm was identified. A CT scan showed a nonenhanced tumor in the left nostril on the uncinate process. A biopsy revealed an intermediate-grade angiosarcoma. Surgical removal followed by radiation therapy was performed with good result. Aerodigestive angiosarcomas have a better prognosis than angiosarcomas of other locations due to better cell differentiation and the presence of early symptoms. Recurrence can occur because of tumor tissue left during resection. Our patient continues tumor free after three years.
We hypothesized that an ERP word repetition paradigm, which reliably elicits and modulates the P600 and N400 components, would be particularly sensitive to the memory deficits and altered synaptic plasticity in mild Alzheimer’s disease (AD). The P600 (a late positive component, or ‘LPC’), and the N400, are sensitive indices of memory encoding and semantic processing, respectively.
We studied 11 patients with mild AD (mean MMSE = 22.9) and 11 elderly (mean age = 77.1) normal controls (NC) on a paradigm in which semantically ‘congruous’ category statement/exemplar pairs (50%) and ‘incongruous’ category statement/non-exemplar pairs (50%) repeat at 10–140 s intervals. A minimum of 19 channels ERP data were recorded and submitted to split-plot ANOVAs.
Normal ERP data showed: (1) a significant word repetition effect for congruous words, with a wide-spread late positivity between ~300 and 800 ms post-stimulus (P600) that is larger for New than Old words; (2) a significant N400 repetition effect for incongruous words, with a right posterior negativity that is reduced for Old relative to New words. By contrast, neither of these word repetition effects was reliably present in the mild AD group. Good group discrimination was achieved by requiring that both these repetition effects were ≥ the 10th percentile, with 100% sensitivity and 82% specificity.
We found significant abnormalities of the N400 and P600 in mild AD, with both potentials showing markedly reduced sensitivity to word repetition.
The absence of normal N400 and LPC/P600 word repetition effects suggests impaired functioning of their neural generators, several of which are located in medial temporal lobe predilection sites (e.g. anterior fusiform, parahippocampal gyrus, hippocampus) for AD/tau pathology.
N400; LPC; P600; Memory; N100
Differences in clinical manifestations are due to virulence factors expressed by the organism.
We studied 455 consecutive episodes of Klebsiella pneumoniae bacteremia occurring in 7 countries. Community-acquired pneumonia and an invasive syndrome of liver abscess, meningitis, or endophthalmitis occurred only in Taiwan and South Africa. Infections by K1 and K2 capsular serotype, the mucoid phenotype, and aerobactin production were important determinants of virulence. The mucoid phenotype was seen in 94% of isolates in patients with community-acquired pneumonia and in 100% of isolates that caused the invasive syndrome in Taiwan and South Africa, compared with only 2% of isolates elsewhere. Mortality of mice injected with mucoid strains (69%) was strikingly higher than that occurring in mice injected with nonmucoid strains (3%, p<0.001). Differences in clinical features of bacteremic infection with K. pneumoniae are due to the virulence factors expressed by the organism.
Klebsiella pneumoniae; gram-negative bacteremia; virulence; epidemiology; research
A Klebsiella pneumoniae clinical isolate was resistant to cefoxitin, cefotaxime, ceftazidime, ceftazidime-clavulanate, piperacillin-tazobactam (MICs, >256 μg/ml in all cases), and meropenem (MIC, 16 μg/ml) and was intermediate to imipenem (MIC, 8 μg/ml). Decreased expression of the OmpK36 porin and expression of an SHV-2 β-lactamase contributed to the observed resistance to these β-lactam-containing agents.
We recently described the use of mini-Tn5 to generate complement-sensitive mutants derived from a complement-resistant Klebsiella pneumoniae clinical isolate deficient in the lipopolysaccharide O side chain. One mutant with a reduced capacity to survive in nonimmune human sera carried the transposon inserted in the htrA gene. We cloned and sequenced the gene and predicted from the deduced amino acid sequence that the putative HtrA homolog contains structural features similar to those of previously described HtrA proteins. To investigate the biological functions and the role of the htrA gene in the virulence of K. pneumoniae, we constructed an isogenic mutant by insertion-duplication mutagenesis. Characterization of the mutant showed that it had greater sensitivity to temperature (50°C) and oxidative stress (H2O2) than the parent strain. Furthermore, the htrA mutant produced less capsule, bound more molecules of complement component C3, and was more sensitive to complement and whole-blood killing than was the parent strain. Finally, disruption of the htrA gene in a virulent K. pneumoniae strain caused a reduction of its virulence in a mice model. Our results indicate that the htrA gene plays an important role in the virulence of K. pneumoniae.
The L-myc restriction fragment length polymorphism has been suggested to be of prognostic significance in some types of primary tumours. We examined the prognostic and susceptibility significance of the L-myc genotype in a group of 98 bladder cancer patients. The L-myc genotype did not correlate with any pathologic parameter and does not offer any clinical utility in patients with bladder cancer. © 1999 Cancer Research Campaign
proto-oncogenes; restriction fragment length polymorphism; bladder cancer; prognostic factors
We have previously demonstrated the existence of Klebsiella pneumoniae clinical isolates deficient in the lipopolysaccharide O side chain, the major factor for resistance to complement-mediated killing in this bacterial species. These isolates are complement resistant, and their mechanisms to resist complement were investigated by selecting transposon-generated complement-sensitive mutants. One mutant with a drastically reduced capacity to grow in nonimmune human serum carried the transposon inserted in an open reading frame of a gene cluster involved in capsule synthesis. This mutant produced less capsule, bound more molecules of the complement component C3, and was more sensitive to complement-mediated and opsonophagocytic killings than was the parent strain. Four additional clinical isolates representing four different K serotypes were studied, and results showed that capsular polysaccharide is a major complement resistance factor in these O side chain-deficient isolates.
Klebsiella pneumoniae porin genes were analyzed to detect mutations accounting for the porin deficiency observed in many β-lactam-resistant strains. PCR and Southern blot analysis revealed the existence of a third porin gene in addition to the OmpK36 and OmpK35 porin genes previously described. This new porin gene was designated ompK37 and is present in all of the clinical isolates tested. The OmpK37 porin gene was cloned, sequenced, and overexpressed in Escherichia coli. In contrast to that of the major porins, OmpK37 porin expression was only detectable by Western blot analysis in porin-deficient β-lactam-resistant strains, suggesting strong down regulation under standard laboratory conditions. Functional characterization suggested a narrower pore for the OmpK37 porin than for K. pneumoniae porins OmpK36 and OmpK35. This correlated with the susceptibility to certain β-lactam antibiotics, since a K. pneumoniae strain expressing porin OmpK37, but not porin OmpK36 or OmpK35, was less susceptible to β-lactam antibiotics than the same strain expressing either porin OmpK36 or OmpK35.
We have demonstrated by using an in vitro approach that interruption of the OmpK36 porin gene by insertion sequences (ISs) is a common type of mutation that causes loss of porin expression and increased resistance to cefoxitin in Klebsiella pneumoniae. This mechanism also operates in vivo: of 13 porin-deficient cefoxitin-resistant clinical isolates of K. pneumoniae, 4 presented ISs in their ompK36 gene.
We have previously described an inhibition enzyme-linked immunosorbent assay method for the O typing of O1 lipopolysaccharide from Klebsiella pneumoniae which overcomes the technical problems and limitations of the classical O-typing method. In this study, we have extended the method to all of the currently recognized O types. The method was validated by studying the prototype strains that have defined the O groups by the classical tube agglutinatination O-typing method. Based on these results, we confirmed the O types of 60 of 64 typeable strains, and we propose a revised O-antigenic scheme, with minor but necessary changes, consisting of serogroups or serotypes O1, O2, O2ac, O3, O4, O5, O7, O8, and O12. Application of this typing method to 638 K. pneumoniae clinical isolates from Denmark, Spain, and the United States from different sources (blood, urine, and others) showed that up to 80% of these isolates belong to serotypes or serogroups O1, O2, O3, and O5, independently of the source of isolation, and that a major group of nontypeable isolates, representing about 17% of the total, consists of half O+ and half O− strains. Differences were observed, however, in the prevalence of the lipopolysaccharide O types or groups, depending on the country and isolation source.
Fifteen isolates of Klebsiella pneumoniae producing extended-spectrum β-lactamases (ESBLs) isolated during a nosocomial outbreak were studied. The strains belonged to the same clonal type, as shown by pulsed-field gel electrophoretic analysis of chromosomal DNA. All the isolates were resistant to extended-spectrum cephalosporins, aztreonam, gentamicin, and fluoroquinolones and were susceptible to carbapenems, tobramycin, netilmicin, and amikacin. None of the isolates expressed the OmpK36 porin. Eight isolates, for which the MICs of cefoxitin were ≥64 μg/ml, showed a diminished level or no expression of a 35-kDa porin. The MICs of meropenem, cefotaxime, and cefpirome were three to eight times higher for porin-deficient isolates than for isolates expressing the 35-kDa porin, but the MICs of imipenem increased two times for porin-deficient isolates compared to those for isolates expressing the porin. This MIC increase reverted to a level similar to that for the parental strain when porin-deficient isolates were transformed with the gene coding for the K. pneumoniae porin OmpK36. It is concluded that the high level of resistance to cefoxitin and the increase in the MICs of meropenem, cefotaxime, and cefpirome for the ESBL-producing K. pneumoniae isolates studied are associated with porin deficiency.
STUDY OBJECTIVE--To describe temporal and geographical variations in mortality from acute reactions to opiates or cocaine and the demographic and toxicological characteristics of persons who died from these in major Spanish cities between 1983 and 1991. DESIGN--Descriptive study. Data were obtained retrospectively from pathologists' reports. SETTING--Cities of Madrid, Barcelona, Valencia, Seville, Zaragoza, and Bilbao. SUBJECTS--Deaths from acute reactions to opiates or cocaine were defined as those in which pathologists' reports did not indicate any other cause of death and in which evidence was found of recent consumption of these drugs. MAIN RESULTS--The mortality rate from acute reactions to opiate/cocaine per 100,000 population in the six cities as a whole rose from 1.2 in 1983 to 8.2 in 1991. Average annual rates for the whole period ranged from 1.7 in Seville to 4.9 in Barcelona. The male/female rates ratio was 5.9:1. The mean age of persons who died rose from 25.1 years in 1983 to 28 years in 1991. In more than 90% of the cases in whom toxicological tests were undertaken opiates were detected, and the proportion in which benzodiazepines or cocaine were detected increased during the period studied. CONCLUSIONS--Between 1983 and 1991 mortality from acute reactions to opiates/cocaine rose dramatically in major Spanish cities and significant differences in mortality between cities were found. Deaths were concentrated among men and young people. Acute drug reactions became one of the leading causes of death in persons 15-39 years of age, representing 11.1% of mortality from all causes in 1988 for this age group. Future studies should examine the relationship between the temporal and geographical variations in this type of mortality and various personal, environmental and social factors.