Analysis of human metaphase chromosomes using antibodies to double-stranded and single-stranded DNA: staining patterns are related to DNA conformation

Fresh and 6-day-old fixed chromosome spreads, both untreated and treated with various banding techniques and nucleases, were stained using monoclonal antibodies to double-stranded and single-stranded DNA. DNA in fixed chromosome preparations became progressively denatured with ageing. The staining pattern of untreated chromosomes with anti-double-stranded DNA antibodies (which resembles G-banding) was determined by the conformation of the chromosomal DNA.     

Analysis of electric and magnetic fields leaking from induction heaters

Results are presented of an investigation on electric and magnetic fields leaking from inductive (magnetic) heaters that are used for thermal processing of high-power electron tubes and lasers in an industrial plant. Measurements of electric and magnetic fields were done using both commercially available and laboratory-developed instrumentation. Isotropic H-field sensors were developed to allow quantitative evaluation of high-intensity magnetic fields. Ten induction heaters with nominal A.C. power ranging from 2.5 kW to 15 kW and operating at frequencies between 300 kHz and 790 kHz were surveyed. Electric field strengths up to 8 kV/m and magnetic field strengths up to 20 A/m were measured.     

Isocitrate lyase: artifacts and multiple enzyme forms

Multiple enzyme forms of isocitrate lyase from various sources have been frequently reported. Protease action after cell rupture was sporadically claimed to explain the observed multiple enzyme forms. In this communication studies which are consistent with a protease action in vitro on isocitrate lyase of Pinus pinea germinating seeds are reported. Moreover, changes in DEAE-Sephacel patterns, mainly related to the age of germination, were observed. Differences regarding the heat stability of the detected enzyme forms were also found. The results indicate that isocitrate lyase from P. pinea may be detected in at least three different forms, one of which is heat stable and may be obtained only at the early stages of germination.     

Specific antibodies in children excreting cytomegalovirus

Acute-and convalescent-phase sera from 22 children were examined by ELISA in comparison with a routine complement fixation (CF) test for detection of anti-CMV antibodies. All these subjects were excreting CMV from urine and/or saliva. The results showed that ELISA is more sensitive than CF test. Particularly ten children showed, by ELISA, anti-CMV antibody titers more agreeing with clinical-virological features. Generally, in other subjects the results of the two serological tests were similar. Three cases showed discordances both between the two methods and between serological data and clinical virological findings.     

Lipoprotein lipase mRNA in neonatal and adult mouse tissues: comparison of normal and combined lipase deficiency (cld) mice assessed by in situ hybridization

Combined lipase deficiency (cld) is a genetic abnormality in mice resulting in the production of enzymatically inactive lipoprotein lipase (LPL). After suckling, these mice have markedly elevated levels of circulating triglyceride. An alteration of LPL gene expression in cld mice may affect the amount and/or the distribution of LPL mRNA in different cell types. Therefore, we performed in situ hybridization for LPL mRNA in tissues from normal and cld pups and adult mice using an antisense 35S-labeled cRNA probe. LPL mRNA had the same pattern of distribution in both cld and normal newborn mice; the probe hybridized strongly to pyramidal neurons of the hippocampus, heart myocytes, and hepatocytes. Despite the lack of noticeable fat stores, LPL mRNA was found in the dermal layer of the skin of cld mice and normal littermates. In adult mice, the cRNA probe for LPL hybridized to the hippocampus, to the heart, and to localized areas of the kidney. We conclude that despite great variation in plasma triglyceride levels, LPL gene is similarly expressed in animals with or without LPL activity.     

Mast Cells Contain Large Quantities of Secretagogue-Sensitive N-Acetylaspartate

Abstract: Mast cells play a central role in both immediate allergic reactions and inflammation. A functional nerve-mast cell interaction has been proposed, given the morphological association between mast cells and neuropeptide-containing peripheral nerves. We now show that purified rat peritoneal mast cells contain large quantities of N -acetylaspartate (NAA; 747.50 nmol/mg of protein). Mast cell levels of NAA were rapidly reduced, by 64.0 and 86.4%, following treatment with compound 48/80 and mastoparan, respectively. These secretagogues strongly decreased mast cell histamine content over the same time period, suggesting also that NAA is stored in secretory granules. The data are the first to show that NAA is present in an immune effector cell type. Because NAA may be involved in myelin synthesis and glutamyl peptide metabolism, NAA released from mast cells following nervous or other stimuli could participate in neuroimmune interactions. Mast cells in multiple sclerosis plaques may contribute to the reported elevations in brain NAA in this disease.     

Distribution in a density gradient of human erythrocytes: sex-related differences

Differences in erythrocyte distribution on Ficoll-Sodium Metrizoate discontinuous density gradient were evaluated between adult males and females. Testosterone and androstenedione plasma levels were tested in males, oestradiol, progesterone and prolactin in both males and females. Female group showed a much higher proportion of lighter younger erythrocytes than males, while males showed higher proportion of denser older cells. Positive correlation was found between young cell percent and oestradiol level, both in males and females, but no correlation was found with androgen hormones.     

Ecological Modeling from Time-Series Inference: Insight into Dynamics and Stability of Intestinal Microbiota

The intestinal microbiota is a microbial ecosystem of crucial importance to human health. Understanding how the microbiota confers resistance against enteric pathogens and how antibiotics disrupt that resistance is key to the prevention and cure of intestinal infections. We present a novel method to infer microbial community ecology directly from time-resolved metagenomics. This method extends generalized Lotka–Volterra dynamics to account for external perturbations. Data from recent experiments on antibiotic-mediated Clostridium difficile infection is analyzed to quantify microbial interactions, commensal-pathogen interactions, and the effect of the antibiotic on the community. Stability analysis reveals that the microbiota is intrinsically stable, explaining how antibiotic perturbations and C. difficile inoculation can produce catastrophic shifts that persist even after removal of the perturbations. Importantly, the analysis suggests a subnetwork of bacterial groups implicated in protection against C. difficile. Due to its generality, our method can be applied to any high-resolution ecological time-series data to infer community structure and response to external stimuli.     

Visual Interactions Conform to Pattern Decorrelation in Multiple Cortical Areas

Neural responses to visual stimuli are strongest in the classical receptive field, but they are also modulated by stimuli in a much wider region. In the primary visual cortex, physiological data and models suggest that such contextual modulation is mediated by recurrent interactions between cortical areas. Outside the primary visual cortex, imaging data has shown qualitatively similar interactions. However, whether the mechanisms underlying these effects are similar in different areas has remained unclear. Here, we found that the blood oxygenation level dependent (BOLD) signal spreads over considerable cortical distances in the primary visual cortex, further than the classical receptive field. This indicates that the synaptic activity induced by a given stimulus occurs in a surprisingly extensive network. Correspondingly, we found suppressive and facilitative interactions far from the maximum retinotopic response. Next, we characterized the relationship between contextual modulation and correlation between two spatial activation patterns. Regardless of the functional area or retinotopic eccentricity, higher correlation between the center and surround response patterns was associated with stronger suppressive interaction. In individual voxels, suppressive interaction was predominant when the center and surround stimuli produced BOLD signals with the same sign. Facilitative interaction dominated in the voxels with opposite BOLD signal signs. Our data was in unison with recently published cortical decorrelation model, and was validated against alternative models, separately in different eccentricities and functional areas. Our study provides evidence that spatial interactions among neural populations involve decorrelation of macroscopic neural activation patterns, and suggests that the basic design of the cerebral cortex houses a robust decorrelation mechanism for afferent synaptic input.     

Chemical Profile and Antioxidant Properties of Extracts and Essential Oils from Citrus × limon (L.) Burm. cv. Femminello Comune

Citrus × limon cv. Femminello Comune (Rutaceae) from Rocca Imperiale (Italy), one of the six Protected Geographical Indication (PGI) Italian lemon crops, has been recently received renewed interest. In this work, fresh and dried peels and leaves were extracted by hydrodistillation, supercritical fluid extraction (SFE), and Soxhlet apparatus. Chemical profile was assessed by gas chromatography (GC) and gas chromatography/mass spectrometry (GC/MS). Except for leaves extracts obtained by Soxhlet apparatus, the monoterpene hydrocarbons fraction dominated. Limonene, γ‐terpinene, and β‐pinene were the main identified compounds. The antioxidant activity was investigated using different in vitro assays namely 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH), ABTS, ferric reducing ability power (FRAP), and β‐carotene bleaching test. In DPPH test, the essential oil obtained by hydrodistillation of fresh peel exhibited the highest activity (IC₅₀ of 1.17 mg/ml). Leaves extracted by SFE showed a good activity in both DPPH and β‐carotene bleaching test with IC₅₀ values of 2.20 and 6.66 mg/ml, respectively. Monoterpene hydrocarbons fraction exhibited a positive Pearson's correlation coefficient with all antioxidant assays. Leaves, often considered waste material, should be considered from a different point because they represent a matrix of indisputable interest.