Just a phase? Causal probing reveals spurious phasic dependence of sustained attention.

For over a decade, electrophysiological studies have reported correlations between attention / perception and the phase of spontaneous brain oscillations. To date, these findings have been interpreted as evidence that the brain uses neural oscillations to sample and predict upcoming stimuli. Yet, evidence from simulations have shown that analysis artefacts could also lead to spurious pre-stimulus oscillations that appear to predict future brain responses. To address this discrepancy, we conducted an experiment in which visual stimuli were presented in time to specific phases of spontaneous alpha and theta oscillations. This allowed us to causally probe the role of ongoing neural activity in visual processing independent of the stimulus-evoked dynamics. Our findings did not support a causal link between spontaneous alpha / theta rhythms and behaviour. However, spurious correlations between theta phase and behaviour emerged offline using gold-standard time-frequency analyses. These findings are a reminder that care should be taken when inferring causal relationships between neural activity and behaviour using acausal analysis methods.

Measurement of muon antineutrino quasielastic scattering on a hydrocarbon target at Eν ~ 3.5 GeV.

We have isolated ν(µ) charged-current quasielastic (QE) interactions occurring in the segmented scintillator tracking region of the MINERvA detector running in the NuMI neutrino beam at Fermilab. We measure the flux-averaged differential cross section, dσ/dQ², and compare to several theoretical models of QE scattering. Good agreement is obtained with a model where the nucleon axial mass, M(A), is set to 0.99 GeV/c² but the nucleon vector form factors are modified to account for the observed enhancement, relative to the free nucleon case, of the cross section for the exchange of transversely polarized photons in electron-nucleus scattering. Our data at higher Q² favor this interpretation over an alternative in which the axial mass is increased.

Measurement of muon neutrino quasielastic scattering on a hydrocarbon target at Eν ~ 3.5 GeV.

We report a study of ν(µ) charged-current quasielastic events in the segmented scintillator inner tracker of the MINERvA experiment running in the NuMI neutrino beam at Fermilab. The events were selected by requiring a µ- and low calorimetric recoil energy separated from the interaction vertex. We measure the flux-averaged differential cross section, dσ/dQ², and study the low energy particle content of the final state. Deviations are found between the measured dσ/dQ² and the expectations of a model of independent nucleons in a relativistic Fermi gas. We also observe an excess of energy near the vertex consistent with multiple protons in the final state.

Improved therapy for children with acute lymphoblastic leukemia and unfavorable presenting features: a follow-up report of the Childrens Cancer Group Study CCG-106.

PURPOSE: On past Childrens Cancer Group (CCG) trials, children with acute lymphoblastic leukemia and unfavorable presenting features had obtained an event-free survival (EFS) rate of no better than 50%. Following promising pilot experience, this study was conducted to determine the benefit and morbidity of two intensive experimental regimens, Reg A, based on the Berlin-Frankfurt-Münster (BFM) 1976 regimen, and Reg B, the New York regimen. PATIENTS AND METHODS: Between February 1983 and November 1984, 217 eligible children with acute lymphoblastic leukemia and unfavorable presenting features were entered and randomly assigned to receive Reg A, Reg B, or Reg C, the control regimen. Assignment to Reg C was halted in November 1984 after interim analyses showed an inferior outcome. Subsequently, between November 1984 and March 1987, an additional 328 patients were randomly allocated to receive Reg A or Reg B. RESULTS: The 7-year EFS rate was 63% (+/- 6%, 1 SD) for Reg A, 61% (+/- 6%) for Reg B, and 40% (+/- 6%) for Reg C (P < .006). The difference between Reg A or Reg B and Reg C remained greater than 20 percentage points for EFS at 7 years and 15 percentage points for survival. Relative to Reg C, patients on Reg A accrued 16.3 additional days of hospitalization on average and, on Reg B, 20.2 days. EFS and survival were similar on Reg A and Reg B, but Reg B required more days of parenteral therapy and greater exposure to anthracyclines and alkylating agents. CONCLUSION: Both Reg A and Reg B provided a better outcome than Reg C for children with acute lymphoblastic leukemia and unfavorable presenting features. Outcomes on Reg A and Reg B were similar. Use of the more effective but more toxic regimens resulted in 78 additional hospital days per relapse prevented on Reg A and 101 days on Reg B. The current CCG trial for this population builds on Reg A.

Cytoreduction and prognosis in acute lymphoblastic leukemia--the importance of early marrow response: report from the Childrens Cancer Group.

PURPOSE: To quantify the residual marrow lymphoblast fraction that best defines patients at high risk for relapse, and the optimal time for assessment during remission induction. PATIENTS AND METHODS: The residual lymphoblast percentage was evaluated on day 7 (n = 220) and day 14 (n = 205) during a four- or five-drug induction in patients with poor prognostic factors. The rate of cytoreduction was related to event-free survival (EFS) and other factors. RESULTS: On the New York (NY) regimen, 68%, 14%, and 18%, and on the Berlin-Frankfurt-Munster (BFM) regimen, 56%, 15%, and 29% of patients had M1 (< 5% blasts), M2 (5-25%), or M3 (> 25%) responses on day 7 (P = .075). On day 14, the corresponding values were 87%, 6%, 7% on NY and 84%, 8%, 8% on BFM. For patients who achieved remission by day 28 and a day-7 marrow rating of M1, M2, or M3, the 6-year EFS rate was 78%, 61%, and 49% (P < .001). The day-14 ratings predicted for a 72%, 32%, or 40% EFS (P < .001). Patients with 5% to 10% blasts day 7 had three times as many events as those with less than 5% and had no better EFS than those with 11% to 25% blasts. Patients with a WBC count more than 200,000/microL at diagnosis and an M1 day 7 marrow had an EFS rate of 69%, while for those with M2 or M3, the EFS rate was 41%. Day-7 marrow had greater prognostic significance than the day-14 evaluation. For slow responders on day 7, the day-14 marrow provided additional information. EFS for patients who achieved M1 by day 14 was 65%. EFS decreased to 20% for those still M2 or M3 on day 14. Day-7 and -14 evaluations had significance for patients of all ages and WBC levels. CONCLUSION: Marrow aspiration on day 7 of therapy provided more useful information than that on day 14. However, day-14 marrow provided additional information for patients with a poor day-7 response. The rate of cytoreduction is a powerful, independent prognostic factor that can identify patients with a slow early response who are at risk for a short remission duration.

Can Fourier transform infrared spectroscopy at higher wavenumbers (mid IR) shed light on biomarkers for carcinogenesis in tissues?

Fourier transform infrared microspectroscopy (FTIR-MSP) has shown promise as a technique for detection of abnormal cell proliferation and premalignant conditions. In the present study, we investigate the absorbance in the sensitive wavenumber region between 2800 and 3000 cm(-1), which has been known to be due to the antisymmetric and symmetric stretching vibrations of CH2 and CH3 groups of proteins and lipids. We report common biomarkers from this region that distinguish between normal and malignant tissues and cell lines. Based on our findings, we propose that the wavenumber region around 2800 to 3000 cm(-1) in the FTIR spectra of cells and tissues could provide valuable scientific evidence at the onset of premalignancy and may be used for ex vivo and in vitro detection of carcinogenesis. To further examine the utility of these markers in cancer diagnosis and management, they are tested successfully in monitoring the changes occurring in leukemia patients during chemotherapy.

Salmonella O antigen-specific oligosaccharide-octyl conjugates activate complement via the alternative pathway at different rates depending on the structure of the O antigen.

Artificial Salmonella serogroup B, D or Cl-specific glycolipids were prepared by covalently linking oligosaccharides corresponding to two O-antigen repeating units, obtained by phage enzyme hydrolysis of native O-antigenic polysaccharides, to octyl residues. Sheep erythrocytes coated with the artificial glycolipids were studied for their ability to consume C3, when incubated in C4- deficient guinea pig serum. Salmonella C1 (0-6,7) glycolipid-coated erythrocytes consumed C3 40% more efficiently than Salmonella D (0-9,12) glycolipid-coated erythrocytes, and 10-times more efficiently than Salmonella B (0-4,12) glycolipid-coated erythrocytes. These results resemble C3 consumption by Salmonella C1, D, and B cells and by sheep erythrocytes coated with purified lipopolysaccharides of these O-specificities. The results prove directly that in a particulate system C3 activation via the alternative pathway depends on the structural properties of the O-antigenic side chain. Structures as small as octasaccharides, or as two O-antigenic repeating units, are sufficient for triggering C3 activation, but the magnitude of activation depends on the nature of the monosaccharides. Apparently, neither the core oligosaccharide nor Lipid A of lipopolysaccharide are required for C3 activation via the alternative pathway.

Smoking and movement disorders in psychiatric patients.

Previous studies have suggested that tardive dyskinesia may occur more frequently in patients who smoke. Further evidence of an interaction between smoking and movement disorders includes the low lifetime exposure to cigarettes found in Parkinson's disease patients. In this study 126 patients with chronic psychiatric illnesses were blindly evaluated for tardive dyskinesia, neuroleptic-induced parkinsonism, and akathisia. Patients who smoked received significantly higher doses of neuroleptics but did not have significantly more frequent or more severe tardive dyskinesia or parkinsonism. Female smokers did have significantly more akathisia. These results are discussed with regard to interactions between smoking, central dopaminergic tone, and the psychopathology of extrapyramidal syndromes. The effect of smoking on neuroleptic blood levels as well as clinical symptomatology is also discussed.

The role of radiation therapy in the treatment of acute lymphoblastic leukemia with lymphomatous presentation: a report from the Childrens Cancer Group.

PURPOSE: Childrens Cancer Group 123 was a trial of intensive multidrug chemotherapy as well as cranial irradiation and bulk disease irradiation in children with acute lymphoblastic leukemia with lymphomatous presentation (bulk disease and either T-cell phenotype, high white blood count, or absence of anemia), a poor prognostic group with an increased risk of central nervous system (CNS) and other extramedullary recurrence. METHODS AND MATERIALS: Three hundred eight patients without CNS disease were randomized among three regimens: A--BFM chemotherapy (designed for high risk ALL patients) with 1800 cGy cranial irradiation; B--LSA2L2 chemotherapy (designed for non-Hodgkins lymphoma patients) with 1800 cGy cranial irradiation and 1500 cGy to nonabdominal bulk disease; C--Reg B without cranial irradiation. All patients received intrathecal methotrexate throughout therapy. Radiation treatment records were reviewed. RESULTS: With a minimum 52-month follow-up, Regimen B and C patients had 5-year actuarial CNS relapses of 7% and 17% (p = 0.01) and event-free survivals of 53% and 39% (p = 0.04). Patients with white blood count < 50,000/mm3 did not benefit from cranial irradiation. Regimen A patients had the same CNS relapse rate as Regimen B patients but an improved event-free survival. Regimen B and C patients with large mediastinal masses who received their assigned chest radiation had a lower event rate than those who did not (p = 0.06). Patients whose cranial fields did or did not encompass the entire meningeal surface had equivalent CNS relapse rates. CONCLUSION: Patients treated with LSA2L2 chemotherapy, a less than optimal regimen, benefited from cranial and mediastinal irradiation. Compliance with radiation volume guidelines was not essential for patients to receive the benefit of cranial irradiation.

The effect of bryostatin on protein kinase C-regulated functions in human T lymphocytes and epidermal keratinocytes.

The bryostatin (Bryo) is a macrocyclic lactone that binds specifically to protein kinase C (PKC) thereby affecting cell growth and differentiation and inhibits phorbol ester-induced tumor promotion. We used human peripheral blood lymphocytes (PBL) and epidermal cells in order to analyze the action mechanism of Bryo and compare it with that of the phorbol ester PMA. Bryo and PMA activated PBL- or T cell-derived PKC in a similar dose-response and induced a similar time kinetic of cytosol-to-membrane translocation of enzymatically active and immunoreactive PKC. In addition, the 2 drugs induced similar patterns of protein phosphorylation and activated the c-fos and c-jun genes that their protein products regulate transcription of TRE-containing genes. In contrast, long-term (20 h) treatment of cells with Bryo resulted in a marked loss of both cytosolic- and membrane-bound PKC while PMA induced only a slight reduction in the amount of cellular PKC. Inhibition of PMA-induced human T-cell proliferation by Bryo correlated with a reduction in the amount of cellular PKC. An opposite effect was observed in human epidermal cells where Bryo augmented growth and proliferation while PMA induced terminal differentiation and cell death. We propose that at least some of the differences in the biological effects induced by Bryo and PMA are due to distinct regulations of PKC. Thus, although both agents can initially bind to and activate PKC at a later time (approximately 16 h), Bryo, but not PMA, induces rapid PKC degradation and inhibition of PKC-regulated biological responses that are dependent on the continuous presence and/or activation of the enzyme.

Xerostomia, xerogenic medications and food avoidances in selected geriatric groups.

OBJECTIVE: To study the relationship between complaints of xerostomia and salivary performance and food avoidances in four geriatric groups chosen to reflect a broad spectrum of individuals along the health-disease continuum. To determine whether xerogenic medications taken by these individuals could be associated with either complaints of xerostomia or with food avoidances. DESIGN: Cross-sectional survey. Clinical examinations and interview. SETTING: A VA dental clinic and a retirement home. PATIENTS AND OTHER PARTICIPANTS: Subjects were 529 individuals older than 56 years of age, living both in institutions and in the community (average age 70 years). Two hundred eight persons were recruited from a VA Dental Clinic, 114 from a residential retirement home, and 132 from a nursing/long-term-care facility; 75 were from an acute care ward and had a diagnosis of a cerebral vascular accident or other neurological condition. OUTCOME MEASURES: Prevalence of xerostomia, dental morbidity, salivary flow, and food avoidances. RESULTS: About 72% of the subjects experienced xerostomia sometime during the day. Stimulated salivary flow was found to be significantly lower in individuals who complained of xerostomia than in those who did not. Fifty-five percent of participants reported using one or more xerogenic medications, with an 86% prevalence in the nursing/long-term-care facility. Individuals with xerostomia had difficulty in chewing and in starting a swallow and were significantly more likely to avoid crunchy foods such as vegetables, dry foods such as bread, and sticky foods such as peanut butter in their diets. Specific medications such as the inhalants ipratropium and triamcinolone and the systemic agents oxybutynin and triazolam could be statistically associated with xerostomia and/or low salivary flow, and/or specific food avoidances. CONCLUSION: Xerostomia apparently affects the ability to chew and start a swallow. This leads to avoidance of certain foods, which raises the possibility that xerostomia could contribute to undernutrition in older persons. The topically applied ipratropium and triamcinolone and the systemic agents amitriptyline, oxybutynin and triazolam could be statistically associated with one or more complaints of xerostomia.

Microgranular acute promyelocytic leukemia--a case with multiple Auer rods demonstrable only after staining for chloroacetate esterase.

In the past several years there has been increasing recognition of the microgranular variant of acute promyelocytic leukemia (APL). This variant is easily mistaken for other types of acute non-lymphocytic leukemia. Its recognition is important because it carries the same high risk of disseminated intravascular coagulation as typical APL. An important clue to the correct diagnosis is the recognition of small numbers of characteristic cells containing multiple Auer rods. This report presents a case in which such Auer-body-containing cells were demonstrable in the marrow only after staining for chloroacetate esterase. They were not apparent with Wright's stain or Sudan black B. The case also highlights the occurrence of variant APL in children and adolescents.

Characteristic absorbance of nucleic acids in the Mid-IR region as possible common biomarkers for diagnosis of malignancy.

FTIR spectroscopy has been extensively used to understand the differences between normal and malignant cells and tissues. In the present study, FTIR microspectroscopy was performed on biopsies to evaluate parameters deduced from changes in nucleic acid absorbance monitored at various characteristic wavenumbers in the Mid-IR region. The data showed that there were differences in the spectra of normal and malignant tissues from several organs such as colon, cervix, skin and blood with respect to absorbance due to nucleic acids. Similar results were observed in the case of cell lines that were transformed to induce carcinogenesis. Of the several ratios examined for consistency in differentiating cancer and normal tissues, the I(996 cm(-1))/I(966 cm(-1)) showed promise as a distinguishing parameter and was comparable to the I(1121 cm(-1))/I(1020 cm(-1)) ratio reported in many earlier studies. The absorbance of nucleic acids is presented with an emphasis on the application of FTIR microspectroscopy for diagnosis of malignancy. Our results indicate that usage of nucleic acid absorbance yield statistically significant parameters, which could differentiate normal and cancerous tissues.

Light-induced apoptosis involves a defined sequence of cytoplasmic and nuclear calcium release in AlPcS4-photosensitized rat bladder RR 1022 epithelial cells.

Oxidative stress induced by light activation of photosensitizers is regarded to have a role in triggering cell death pathways during photodynamic therapy (PDT). Reactive oxygen species have been proposed to act as signal transduction molecules activating downstream reactions that lead to apoptosis. Mainly debated is the cooperating role of other signaling systems like calcium or pH. The present work contributes to this discussion by studying PDT effects in cell cultures of rat bladder epithelial cells for the hydrophilic tetrasulfonated aluminum phthalocyanine (AlPcS4). Cells were coincubated with the photosensitizer and the calcium-sensitive probe Fluo-3. The light-induced reactions were analyzed with a confocal laser scanning microscope. The dynamics of the process during light activation was observed with subcellular resolution. A transient calcium elevation during the irradiation process was detected, especially in the cell's nuclei, followed by a more sustained increase. The evaluation of the energy-dose-dependent phototoxicity after an incubation time with the photosensitizer of 1 and 24 h, showed enhanced phototoxicity when the drug was present for 24 h. Surprisingly, stimulation of cell proliferation was observed at very low light doses (at 0.2 J/cm2) when the drug was incubated for 24 h (cell viability 160%). Induction of apoptosis could be observed after irradiation with fluences between 1 and 3 J/cm2. Apoptotic cells were identified with fluorescein isothiocyanate-labeled Annexin V, which binds to phosphatidylserine after its translocation to the outer plasma membrane. In the presence of the antioxidant pyrrolidinedithiocarbamate the transient calcium elevation was totally inhibited, as was the subsequent translocation of PS. In contrast, N-acetyl-L-cysteine did not suppress the transient calcium increase. Our data might be consistent with calcium regulated processes during AlPcS4-PDT and the involvement of oxygen radicals.

Application of FTIR microscopy for the characterization of malignancy: H-ras transfected murine fibroblasts as an example.

Recently, microscopic FTIR is widely used in the field of biology and medicine. FTIR can detect biomolecular changes in the cells and tissues responsible for various disorders. In this report, we characterize the H-ras transfected fibroblasts and its normal control using microscopic FTIR. The intensity of the normal fibroblasts was higher than that of H-ras transfected fibroblasts. Our studies showed significant differences occur in the concentration of vital metabolites upon transformation. The DNA and carbohydrates level decreased in the transformed cells compared to the controls. A linear correlation could be found between the levels of carbohydrates and phosphate, while the RNA/DNA ratio varied inversely with glucose/phosphate levels.

Fluorescence spectroscopy for detection of malignancy: H-ras overexpressing fibroblasts as a model.

Autofluorescence from intracellular chromophores upon illumination of cells by monochromatic light has been studied towards the development of novel noninvasive and sensitive technology for the early detection of cancer. To investigate the relationship between biochemical and morphological changes underlying malignant disease and resulting fluorescence spectra, an in vitro model system of a paired normal and malignant murine fibroblasts cell lines, differing in cancer-associated H-ras expression was employed. A comparison of fluorescence excitation and emission spectra of proliferative cells revealed that fluorescence intensity of malignant cells was significantly less than that of normal cells upon excitation at 290 nm. Fluorescence of both cell lines decreased with decreasing cell concentration, but at each concentration, normal cells had higher fluorescence intensity than malignant cells. Similar differences between the cell lines were observed when brought to quiescence or at stationary phase. Results suggested that the chromophore contributing most significantly to these spectra is tryptophan and its moieties in proteins. This model system demonstrates the specific contribution of H-ras to subcellular chromophores, resulting in a significant difference in their autofluorescence intensity, and implies the potential use of the technique for cancer detection. This model system is potent for analysis of the contribution of other oncogenes and their combinations towards spectral detection of cancer.

Puberty gingivitis in insulin-dependent diabetic children. I. Cross-sectional observations.

This cross-sectional study examined the gingivitis occurring at puberty in a population of insulin-dependent juvenile diabetics. Seventy-seven children between the ages of 6 and 15 years were examined for gingivitis levels, stages of pubertal maturation and blood levels of glucose and glycosylated hemoglobin. Bacterial plaque was sampled from one or more approximal tooth surfaces of every subject and cultured under anaerobic and aerobic conditions on nonselective and selective media. The total cultivable flora and percentage of certain presumptive periodontopathic bacteria were determined. Before puberty, children with "high" levels of glycosylated hemoglobin also had higher gingivitis levels than children with "normal" metabolic control of diabetes. During puberty, the level of gingivitis increased independently from both fasting blood glucose levels and per cent glycosylated hemoglobin. The microbiota of marginal plaque was predominantly composed of facultatively anaerobic bacteria. The percentages of Capnocytophaga sp and Actinomyces naeslundii were statistically higher at the onset of puberty, suggesting that a specific bacterial shift in the microbial composition of marginal plaque occurs in response to host changes in juvenile diabetic children at this age period.

Initial steps in Streptococcus pneumoniae interaction with and pathogenicity to the host.

Streptococcus pneumoniae (Pnc) is one of the leading pathogens in the world. Attachment to respiratory mucosal and lung surfaces is presumed to be involved in carriage, in disease and in the interaction with macrophages initiating innate immune responses. We hypothesized that bacterial adhesins mediate Pnc adhesion and host cell invasiveness. Initial studies have focused on the purification of cell wall and membrane proteins using fetuin affinity chromatography, SDS PAGE and western blot analysis probed with pooled healthy human sera. Using a Pnc clinical isolate, and a gpt mutant we have detected 10-lectin proteins isolated from the cell wall and adherent to the affinity column and 15 lectins isolated from membrane extracts. The fetuin-captured lectins agglutinated rabbit erythrocytes. 15 proteins in the cell wall and 18 proteins in the membrane that failed to bind to the fetuin column did not agglutinate rabbit erythrocytes. Further purification of the cell wall and membrane fetuin-separated fractions was achieved via anion exchange FPLC, was verified by SDS PAGE. These proteins maintained their agglutinating activity, and were subsequently tested for their ability to interfere with Pnc adhesion and invasion of epithelial cells in culture. Additional biochemical, immunological and molecular techniques are being used in attempt to identify relevant proteins.

Minor salivary gland secretion in the elderly.

OBJECTIVE: Very little information exists on minor salivary gland output (MSGO) in health and disease. We investigated the minor salivary gland output of elderly subjects with different medical backgrounds and the relationship of that output with life practices, demographic variables, complaints of dry mouth, medication usage, functional status, medical treatments, and dental and medical variables. STUDY DESIGN: MSGO was measured with a special moisture-detecting paper on the lip, cheek, and palate, which comprised the total MSGO. A parsimonious linear regression model was developed to determine which of the many measured variables influenced the MSGO. RESULTS: There were significant differences in MSGO between the recruitment sites, with the non-Veteran Affairs (VA) Independent Living participants having significantly lower MSGO than the VA groups. A secretion rate for MSGO based on median values from all subjects of <4.6 microL/min was categorized as being low, whereas a secretion rate for MSGO >/=4.6 microL/min was categorized as high. A regression model was used to examine variables that could be associated with MSGO variability. The results show that being older, a woman, a current smoker, and having a complaint of dry mouth were associated with lower MSGO rates. CONCLUSIONS: An association between subjective complaints of dry mouth and a decrease in MSGO measured objectively was demonstrated in this elderly population. Furthermore, age and sex effects on MSGO were also demonstrated.