Ocular motor disorders in children and adults with mTBI: a scoping review protocol.

INTRODUCTION: Ocular motor function is susceptible to neurological injury because it requires a large portion of brain circuitry including every lobe of the brain, brainstem, thalamus, basal ganglia, cerebellum, cranial nerves and visual tracts. While reports of a high frequency of ocular motor dysfunctions after mild traumatic brain injury (mTBI) span multidisciplinary journals, there is no scoping review of the signs, diagnostic assessments and criteria, and appropriate management of ocular motor disorders post-mTBI. Post-mTBI ocular motor dysfunction has been reported to respond to active treatment. The objective of this scoping review is to map the available evidence on the diagnostic assessment and treatment modalities currently used in the management of mTBI-related ocular motor disorders in children and adults. This scoping review also aims to identify gaps in the current literature and provide suggestions for future research. METHODS AND ANALYSIS: This review will include populations with reported concussion and/or mTBI without restrictions on age, race, sex or time since injury. The review will evaluate the reported symptoms related to ocular motor dysfunction, types of assessments and diagnostic criteria used, reported treatments, and the level of evidence supporting the reported treatments. This review will exclude literature on brain injury of non-traumatic aetiology and moderate/severe traumatic brain injury. Ocular motor dysfunction after mTBI appears in journals across multiple disciplines. Thus, multiple databases will be evaluated including Pubmed, Embase, PEDro, OVID, Clinical Key, Google Scholar and REHABDATA. Literature will be searched from inception to present day. Evidence sources will include experimental study designs including randomised controlled trials, non-randomised controlled trials and interrupted time-series. Additionally, analytical observational studies including prospective and retrospective cohort studies, case series, cross-sectional studies and clinical practice guidelines will be considered for inclusion. Data will be extracted on clinical presentation, frequency, assessment, diagnostic criteria management strategies and outcomes of concussion and mTBI-related ocular motor disorders. ETHICS AND DISSEMINATION: This scoping review will use data from existing publications and does not require ethical approval by an institutional review board. Results will be disseminated through publication in a peer-reviewed scientific journal and presented at relevant conferences and as part of future workshops with professionals involved with diagnosis and management of patients with mTBI.

The ability of cystamine to bind DNA.

The DNA-binding properties of cystamine compared with natural occurring polyamines have been studied in vitro by means of ethidium bromide displacement assays, studies of DNA thermal stability and analyses of DNA-B/DNA-A transition. While the first two methods did not put in evidence any peculiar property in the binding capability of cystamine, CD studies showed the interesting ability of cystamine to shift the equilibrium B/A-DNA towards the B-form. In the same experimental conditions spermine and spermidine induced the A form of DNA, instead putrescine and cadaverine did not show any particular activity. The ability of cystamine to bind DNA, as shown also by its DNA radioprotective capability, might be important in chromatin condensation and stabilization, and might be a cause of the antiviral activity observed by some authors.

Cystamine transport in spheroplasts of Saccharomyces cerevisiae.

This work is the first demonstration that cystamine is actively accumulated in spheroplasts of Saccharomyces cerevisiae. We have identified and quantitatively determined the transported cystamine in extracts of spheroplasts that have been incubated over different time periods and in the presence of different amounts of cystamine. The method used, already reported in literature for the identification of natural aliphatic polyamines in biological fluids, consists of a derivatization of spheroplast extracts with dabsyl-chloride and subsequent chromatographic analysis in HPLC. Our results show that cystamine accumulation is a function of time, it increases up to 2.5 min then decreases. Transport is inhibited by natural aliphatic polyamines, which, at the same concentration of cystamine (1 mM), cause a decrease in cystamine transport of about 90% for spermidine, 50% for spermine and only 15% for putrescine. Furthermore, transport is energy-dependent as demonstrated by a significant decrease observed in the presence of 2,4-dinitrophenol, ouabain and vanadate. In particular 0.2 mM ouabain causes a decrease of more than 60% in cystamine transport. Our data suggest that cystamine is transported in Saccharomyces cerevisiae spheroplasts via the same polyamine transport system(s) known to be operating in higher eukaryotic cells.

[Rehabilitation of deafness in the elderly: multidisciplinary intervention in experimental university center]. / La riabilitazione nella sordità dell'anziano: intervento multidisciplinare in un centro universitario sperimentale.

The loss of hearing abilities can be seen as a complex event because psychological discomfort and relational inhibitions interact and lead to behaviours and attitudes which are insidious and dangerous for the quality of life of the patient. The complexity of the psychological-organic inconvenience, such as impairement disability and handicap led to the testing of recovery patterns. In this specific context interventions coming from different fields sustained from a complex operative model where different professional competences and evaluation processes interact. Therapeutic interventions have been carried out by an audiologist, an audiometrist, a speech therapist, an audioprostethist and a psychologist, all sharing the obtaining of the same result. The role of the audiologist is simply clinical and concerns the knowledge of the entire process of rehabilitation through the use of a prosthesis. This process concerns the audiologist, who operates in close collaboration with the audiometrist and the audioprosthesist: it is therefore a therapeutic activity that is interested mainly in the prescription of the prosthesis and the restoring of the communicative function. The speech therapist and the psychologist carry their interventions through a relationship with the patient, which places the respect of the patient's personality before any other procedural and technical aspect. Therefore they pay attention more to ergonomic factors than to the hearing loss, through the obtaining of the patient's self-confidence and of a better general psychological situation. Therefore the main purpose of each intervention is to create a process of rehabilitation aimed at restoring the communicative functions and the individual motivation in trying to do so both in the domestic and in the social environment. The authors refer the experience and the informations put together during three years of research activity. The results of the therapeutic intervention have brought to the acceptance of the prosthesis help, the adaptation to amplification, the reduction of the subjective and relational uneasiness for the use of prosthesis, the use of the prosthesis, the reintroduction to the world of sounds, the restoring of levels of autonomy and of self-estime, the discover of eventual abilities, which had never been used or underestimated, the reactivation of more rewarding social relationships and the reduction of the conditions of dependency related to the hearing disability.

Inhibition of CpG methylation in linker DNA by H1 histone.

H1 exerts a specific in vitro inhibitory effect on enzymic DNA methylation. The experiments reported in this paper were undertaken in order to assess whether the lower methylation level found in internucleosomal DNA compared to core DNA is the in vivo consequence of the well-known localization of this histone in the linker region, as opposed to a possible deficiency of CpG dinucleotides in linker DNA. The methyl-accepting ability of H1-depleted oligonucleosomes from human placenta and of the corresponding core particles were assayed by addition of purified DNA methyltransferase, using S-adenosylmethionine as the methyl group donor. We have found that approx. 80% of newly-incorporated methyl groups are localized in linker DNA, which is indeed a good potential substrate for enzymic DNA methylation. Addition of quasi-physiological amounts of H1 to H1-depleted oligonucleosomes markedly reduced their methyl-accepting ability, while exerting a re-condensing effect on these particles, as revealed by the distortions of their circular dichroism spectra.

Histones and DNA methylation in mammalian chromatin. II. Presence of non-inhibitory tightly-bound histones.

After removal, by high-salt extraction, of the loosely-bound components present in human placenta chromatin, tightly-bound cationic proteins could be solubilized, by acid extraction, from the 'stripped' chromatin, as well as from the 'stripped' loops or from the 'digested matrix'. These acid-soluble tightly-bound proteins are, in terms of apparent molecular mass and immunoreactivity, quite similar to the 'typical', loosely-bound histones, and, similarly to their 'loosely-bound' counterparts, they can be subdivided in distinct H1-, H2A-, H2B-, H3- and H4-like components, the 'digested matrix' being however characterized by the absence of tightly-bound H1. These tightly-bound histones, at variance from the 'typical' ones, readily find a right-handed helical conformation upon renaturation by progressive dialyses. The H1 components strongly differ also in their effects on enzymic DNA methylation: while 'typical' H1 has a strong inhibitory effect, its tightly-bound counterpart exerts a slight but definite stimulation.

Histones and DNA methylation in mammalian chromatin. Differential inhibition by histone H1.

Histones (from calf thymus or from human placenta), if renatured in the presence of EDTA, caused a severe inhibition of in vitro methylation of double-stranded DNA (from Micrococcus luteus) by human placenta DNA methyltransferase. The absence of EDTA during the histone renaturation procedure abolished--at least in the 'physiological' range of the histones/DNA ratio--the inhibition. The H1 component was responsible for this inhibition, no effect being exerted by the other histones. H1 preparations were more effective if renatured in the presence of EDTA--90% inhibition being reached at a 0.3:1 (w/w) H1/DNA ratio. It seems likely that the requirement for the presence of EDTA during the renaturation process is correlated to its ability to induce a fairly stable ordered conformation of the histones, although this effect could also be shown with the 'inactive' H2a, H2b and H3 components, and was instead less evident with histone H1. The restriction to histone H1 of the ability to inhibit enzymic DNA methylation may account for the lower methylation levels present in the internucleosomal DNA of mammalian chromatin.

Isolated brain microvessels as in vitro equivalents of the blood-brain barrier: selective removal by collagenase of the A-system of neutral amino acid transport.

On treatment with collagenase, brain microvessels, together with several protein components, lose some enzymatic activities such as alkaline phosphatase and gamma-glutamyltranspeptidase, whereas no change occurs in the activities of 5'-nucleotidase and glutamine synthetase. The energy-requiring "A-system" of polar neutral amino acid transport is also severely inactivated, whereas the L-system for the facilitated exchange of branched chain and aromatic amino acids is preserved. In the collagenase-digested microvessels, this leads to loss of the transtimulation effect of glutamine on the transport of large neutral amino acids, because such transtimulation is due to a cooperation between the A- and L-systems. By contrast, NH4+ maintains (and even enhances) its ability to stimulate the L-system of amino acid transport, presumably through glutamine synthesis within the endothelial cells.

Affinity chromatographic purification of nucleosomes containing transcriptionally active DNA sequences.

The unfolding of nucleosome cores in transcriptionally active chromatin uncovers the sulfhydryl groups of histone H3, making them accessible to SH-reagents. This has suggested that nucleosomes from active genes could be retained selectively on organomercurial/agarose columns. When nucleosomes released from rat liver nuclei by limited digestion with micrococcal nuclease were passed through an Hg affinity column, a run-off fraction of compact, beaded nucleosomes was separated from a retained nucleosome fraction. Although both contained monomer-length DNA and a full complement of core histones, histones in the retained fraction were hyperacetylated. Dot blot hybridizations showed the Hg-bound nucleosome fraction to be enriched in DNA sequences transcribed by hepatocytes (serum albumin and transferrin genes), while a brain-specific gene (preproenkephalin) was not retained, but appeared in the nucleosomes of the run-off fraction. The results are discussed in light of other evidence linking hyperacetylation of histones H3 and H4 to conformational changes at the middle of the nucleosome core.

Risk of biliary surgery in patients with hyperbilirubinemia.

Previous studies have suggested a direct relationship between the serum bilirubin level and the risk of operation. However, patients with high bilirubin levels are usually older and have associated conditions unrelated to jaundice that may contribute to the development of postoperative complications. We studied the courses of 98 consecutive patients who were admitted with biliary obstruction and a serum bilirubin level of 10 mg/dl or greater and underwent operation. Sixty-one had neoplastic obstructions, 26 had benign biliary strictures, 8 had choledocholithiasis, and 3 had other obstructive lesions. Comorbid factors were evaluated and assigned a score to reflect their severity. Neither age nor advanced local cancer was considered to be a comorbid factor. Biliary obstruction was treated by resection of the bile duct, the pancreas, or both in 28 patients, by bilioenteric bypass in 55 patients, and by other operations in 15 patients. Postoperatively, complications developed in 30 patients and 8 died. There was no correlation between the admission serum bilirubin level, hematocrit value, or serum albumin level and the development of complications or death. There was a strong correlation between the presence of severe associated disease and the risk of postoperative complications or death. Nineteen of 81 patients with a comorbid score below 4 had a complication compared with 11 of 17 patients with scores of 4 or higher (p less than 0.01). Two of the 81 patients with scores below 4 died compared with 6 of 17 patients with a score of 4 or higher. These findings show that postoperative deaths and serious complications in patients with severe jaundice are principally the result of uncontrolled associated disease and that jaundice per se does not contribute substantially to an undesirable outcome.

Tightly bound non-histone proteins: distribution of tissue-specific components in the chromatin organization.

We have investigated the distribution of tissue-specific tightly bound non-histone proteins in the first and third levels of chromatin organization. The proteins of this class have been extracted from whole chromatin and chromatin fractions prepared from pig liver or kidney. The tissue-specific proteins have high molecular mass (ranging from 135 KDa to 70 KDa in liver, over 135 KDa in kidney) and in kidney a more basic isoelectric point. These proteins are mainly located outside the core particles, and are instead present only in the chromatin matrix, become more intense after extensive digestion of the matrix with DNAase I.

Distribution of tissue-specific tightly bound non-histone proteins in the first level of repeating chromatin structures.

Non-histone proteins, tightly bound to DNA, have been extracted from whole chromatin and core particles prepared from pig liver or kidney. We have investigated by bidimensional slab gel electrophoresis the distribution of this protein class in the first level of repeating structure of chromatin. Our results reveal that non-histone proteins tightly bound to DNA are a heterogeneous protein class. Some of them, particularly in the core particles, appear to be essentially the same in both tissues, though having differences in their isoelectric point, which may be attributed to postsynthetic modifications. We have calculated that this protein class is associated to only 10% of nucleosomes, these nucleosomes having, on the average, one protein molecule for each core DNA. The tissue-specific proteins have high molecular mass (ranging from 135 kDa to 70 kDa in liver, over 135 kDa in kidney) and, in kidney, a more basic isoelectric point. These proteins are mainly located outside the core particles; they could be situated in the spacer regions and/or be involved in determining higher levels of chromatin organization.

Distribution of tightly bound non-histone proteins in chromatin fractions obtained by DNAase II digestion.

Digestion of pig liver chromatin with DNAse II afforded three different fractions which were characterized in terms of their DNA, RNA and tightly bound non-histone protein content, their DNA fragment size and their template activity. Two of these fractions are soluble after digestion with DNAase II and have been separated on the basis of their different solubility in MgCl2. A third fraction is not solubilized even after extensive digestion, although the size of its DNA is comparable to that of the enzyme solubilized fractions. The three fractions show qualitatively and quantitatively different distribution of tightly bound non-histone proteins, with specific protein components in each fraction; furthermore the non-solubilized fraction is greatly enriched in proteins tightly bound to DNA. From all the data obtained it can be suggested that the tightly bound proteins of the insoluble fraction may play, directly or indirectly, a role in maintaining an organized chromatin structure.

Distribution of tissue-specific tightly bound non-histone proteins in chromatin fractions obtained by DNAase II digestion.

The tissue specificity of a particular class of non-histone chromatin proteins characterized by strong bonds to DNA, tightly bound non-histone chromatin proteins (t.b. NHCp), was investigated. In connection with its possible role in the cell differentiation, its distribution in chromatin fractions obtained by digestion with DNAase II and precipitation with MgCl2 was studied. It was shown by bidimensional gel electrophoresis that some proteins of this class are tissue specific for pig liver compared to kidney chromatin. For both tissues, most tissue specific proteins were found to be peculiar to the chromatin fraction that remains insoluble after prolonged digestion with DNAase II. The proteins found in this chromatin fraction are common to the nuclear matrix proteins and, considering the chromatin organization, may be involved in the attachment point for loops in the axial matrix structure. It is possible that proteins of this class, directly or indirectly, play an important role in the regulation of transcription and differentiation in eukaryotes, by modulating the supercoiled state of DNA.

The interaction of bisbenzimide with DNA.

The interaction of bisbenzimide (Hoechst 33258) with DNA has been studied by microcalorimetry, fluorimetry and fluorescence polarization measurements. The binding does not involve intercalation, takes place in at least two modes and occurs in the major groove at low dye/DNA molar ratio (first mode of binding), in agreement with previous proposals by other Authors. Furthermore it has been shown that i) at high dye/DNA molar ratio the binding (second mode) occurs in both grooves; ii) at pH 7.0 the protonation of a dye nitrogen accompanies the binding in both modes; iii) the quantum yield of the dye-DNA complex is sensitive to the DNA conformation change caused by an increase in ionic strength. Basically the same type of binding takes place on chromatin, as detected by calorimetry. However, at high dye/DNA molar ratio about 30% of DNA is not accessible to the dye. The decreased accessibility appears to be mainly related to the nucleosomal structure of chromatin.

Tightly bound non-histone proteins in nucleosomes from pig-liver chromatin.

Core particles prepared by micrococcal nuclease digestion of pig liver chromatin have been adsorbed on hydroxyapatite and dissociated by gradual increase in ionic strength and finally by urea and guanidine. By this method non-histone proteins have been found to be associated with the core particles. Proteins tightly bound to the core particle DNA (i.e. dissociated only by urea and guanidine) have also been found: these are proteins with a limited heterogeneity, with respect to their molecular weights, since only six components are present with molecular weights ranging from 71000 to 20000. They show, furthermore, a peculiar amino acid composition. Other tightly bound proteins have been shown to be present only in the spacer regions. The existence of two different classes of tightly bound proteins probably reflects different modes of binding to the DNA, which are compatible or incompatible, respectively, with the simultaneous binding of the histone octamer.

Fractionation of non-histone chromatin proteins from pig liver and kidney by means of immobilized histone H3.

The non-histone chromatin proteins (NHCp) from pig liver and kidney have been partially fractionated in non-denaturing conditions by the use of histone H3 immobilized on agarose and the fractions obtained have been analysed by SDS-polyacrylamide gel electrophoresis and amino acid analysis. At least six different fractions have been obtained by successive increases of the ionic strength of the medium. Few NHCp have been evidentiated with subunit molecular weights 55,000 and less than 30,000, which diaplay a remarkably high affinity for histone H3, and require 5 M urea to be displaced from the immobilized histone. The elution patterns of the NHCp from liver and kidney, although very similar, reveal some significant differences between the two tissues, which are undetectable by SDS-electrophoresis and which are most likely due to tissue specific proteins. This histone-affinity chromatography appears to be a promising approach for the analysis of specific histone-NHCp interactions, and as a first step for NHCp purification.