Changes in gait variability during different challenges to mobility in patients with traumatic brain injury.

Postural stability may be compromised in patients who have sustained a traumatic brain injury (TBI). The purpose of the present study was to examine dynamic stability during gait by measuring spatial and temporal variability of foot placement, and to determine the effect of increased difficulty of the walking task on gait variability in patients with TBI. It was hypothesized that patients with TBI will show increased variability in step time, step length, and step width in comparison to healthy controls and that such differences would be accentuated by increased task difficulty. Participants (patients: n=20, controls: n=20) were asked to walk across a pressure sensitive mat at their preferred pace (PW), as fast as possible (FW), and with their eyes closed (EC). In accordance with the hypotheses, patients had significantly greater variability in step time and step length in comparison to healthy controls, and when the complexity of the gait task increased (FW and EC tasks). Although step width variability showed no significant difference between the groups, both control and patient groups had increased step width variability in the EC task. It is proposed that such increases in variability reflect greater challenges to maintaining dynamic stability during gait among individuals with TBI and when performing more difficult tasks.

The Community Balance and Mobility Scale--a balance measure for individuals with traumatic brain injury.

OBJECTIVE: To provide evidence for the validity and reliability of a new outcome measure of balance, the Community Balance and Mobility Scale, developed for the ambulatory individual with traumatic brain injury. DESIGN: A validity and reliability study. SETTING: Acute care, in- and outpatient rehabilitation and day hospital settings. SUBJECTS: Two convenience samples (n=36, 32) of ambulatory patients with traumatic brain injury. MAIN MEASURES: The content and construct validity, test-retest, inter- and intra-rater reliability and internal consistency of the Community Balance and Mobility Scale. RESULTS: Content validity was demonstrated by the involvement of patients with traumatic brain injury (n=7) and clinicians (n=17) in the process of item generation and by physical therapists' ratings of item relevance. Further support is the correlation of the Community Balance and Mobility Scale scores with physical therapists' global balance ratings of the patient (r=0.62). Construct validity was supported by the ability of the measure to differentiate between patients along the continuum of care and also by comparisons with maximal walking velocity (r=0.64). Patients who scored greater than or less than 50 on the balance measure demonstrated significantly different Community Integration Questionnaire scores (P=0.004). The Community Balance and Mobility Scale demonstrated intraclass correlation coefficients (ICCs) of 0.977, 0.977, 0.975 and Cronbach's alpha of 0.96 for intra-, inter-, test-retest reliability and internal consistency, respectively. CONCLUSION: The Community Balance and Mobility Scale is a valid and reliable outcome measure for the ambulatory individual with traumatic brain injury.

Drill cutting accumulations in the Northern and Central North Sea: a review of environmental interactions and chemical fate.

The exploration and production of North Sea oil and gas reserves has resulted in the accumulation of large quantities of drill cuttings on the seabed surrounding drill sites. This complex mixture of man-made and natural substances contains higher concentrations of certain metals (Ba, Cr, Cu, Ni, Pb, and Zn) and hydrocarbons than are observed in background sediments. With decommissioning of older platforms underway, an evaluation of the environmental interactions and chemical fate of the drill cuttings accumulations is required. This review concentrates on contaminants within drill cutting accumulations in the Northern and Central North Sea (56 degrees N-62 degrees N). Present literature reviewed reveals that hydrocarbons within the cuttings piles remain relatively unchanged with time. A considerable proportion of the associated contaminants are likely to remain within the cuttings pile unless they are disturbed which will then increase exchanges of porewater and solids back to the seabed surface resulting in pathways of exposure for organisms.

Interferon alpha2b gene delivery using adenoviral vector causes inhibition of tumor growth in xenograft models from a variety of cancers.

A recombinant adenovirus expressing human interferon alpha2b driven by the cytomegalovirus promoter, IACB, was shown to produce and secrete biologically active protein in vitro and in vivo. Intravenous administration of IACB in Buffalo rats resulted in circulating levels of biologically active human interferon at 70,000 international units/mL for up to 15 days. Distribution of interferon protein after IACB administration was different from that seen with the subcutaneous delivery of interferon protein. Higher levels of interferon protein were observed in liver and spleen after IACB delivery compared to protein delivery. The antitumor efficacy of IACB, as measured by suppression of tumor growth, was tested in athymic nude mice bearing established human tumor xenografts from different types of human cancer. Subcutaneous tumors most responsive to the intratumoral administration of IACB ranked as U87MG (glioblastoma) and K562 (chronic myelogenous leukemia), followed by Hep 3B (hepatocellular carcinoma) and LN229 cells (glioblastoma). Intravenous administration of IACB in animals bearing U87MG or Hep 3B xenografts was also effective in suppressing tumor growth, although to a lesser extent than the intratumoral administration. IACB was also tested in a metastatic model in beige/SCID mice generated with H69 (small cell lung carcinoma) cells and was found to prolong survival in tumor-bearing animals. This suggested that interferon gene delivery can be effective in suppressing tumor growth in a wide variety of cells.

Re-engineering adenovirus regulatory pathways to enhance oncolytic specificity and efficacy.

Replicating adenoviruses may prove to be effective anticancer agents if they can be engineered to selectively destroy tumor cells. We have constructed a virus (01/PEME) containing a novel regulatory circuit in which p53-dependent expression of an antagonist of the E2F transcription factor inhibits viral replication in normal cells. In tumor cells, however, the combination of p53 pathway defects and deregulated E2F allows replication of 01/PEME at near wild-type levels. The re-engineered virus also showed significantly enhanced efficacy compared with extensively studied E1b-deleted viruses such as dl1520 in human xenograft tumor models.

Selective expression of nonsecreted interferon by an adenoviral vector confers antiproliferative and antiviral properties and causes reduction of tumor growth in nude mice.

Replication-deficient adenoviruses expressing human interferon-alpha2b (HuIFN-alpha2b) or the hybrid IFN-alpha2alpha1 or those with the secretory signal deleted, whose express is driven by the alpha-fetoprotein (AFP) promoter, were constructed and characterized. Synthesis of IFN protein and secretion or intracellular retention were tested by Western blotting and immunoassay. Expression of IFN by the recombinant adenoviruses was restricted to cells that constitutively express AFP. In these cells, expression of both secreted and nonsecreted recombinant IFN resulted in inhibition of cell proliferation, resistance to viral infection, induction of major histocompatibility complex (MHC) class I expression, increased apoptosis, and activation of an IFN-stimulated response element (ISRE)-containing promoter. Also, the induction of protein kinase R (PKR), increased phosphorylation of Stat1, and accumulation of hypophosphorylated pRb were observed for both the secreted and nonsecreted IFN, suggesting that the nonsecreted IFN may act through a similar pathway. Hep3B cells, an AFP-positive line derived from a patient with hepatocellular carcinoma (HCC), were injected subcutaneously (s.c.) into athymic nude mice to generate established tumors. Intratumoral injection of recombinant adenoviruses expressing secreted as well as the nonsecreted IFN caused suppression of tumor growth. As the AFP promoter is activated in many HCC cells but is silent in normal cells, these constructs may be useful in restricting IFN effects to the tumor cells while reducing toxicity to the neighboring tissues.

Evaluation of E1-mutant adenoviruses as conditionally replicating agents for cancer therapy.

The oncolytic effect of adenoviruses may provide an efficient means to destroy tumor tissue if viruses could be developed with sufficient selectivity and efficacy. In this report we have characterized several adenoviruses, each with different mutations in the E1 region, for selective cytopathic effect in tumor cells in vitro and for their ability to inhibit tumor growth in vivo. Of the E1 mutants tested, we have identified one, E1Adl01/07, which preferentially induces cytopathic effects in a range of tumor cells versus primary cells. In addition, E1Adl01/07 significantly inhibited tumor growth and increased survival of mice in several models of human cancer. These results suggest that E1Adl01/07 might serve as an effective cancer therapeutic, combining both selectivity and efficacy.

A developmental timer regulates degradation of cyclin E1 at the midblastula transition during Xenopus embryogenesis.

We have analyzed cyclin E1, a protein that is essential for the G1/S transition, during early development in Xenopus embryos. Cyclin E1 was found to be abundant in eggs, and after fertilization, until the midblastula transition (MBT) when levels of cyclin E1 protein, and associated kinase activity, were found to decline precipitously. Our results suggest that the reduced level of the cyclin E1 protein detected after the MBT does not occur indirectly as a result of degradation of the maternally encoded cyclin E1 mRNA. Instead, the stability of cyclin E1 protein appears to play a major role in reduction of cyclin E1 levels at this time. Cyclin E1 protein was found to be stable during the cleavage divisions but degraded with a much shorter half-life after the MBT. Activation of cyclin E1 protein turnover occurs independent of cell cycle progression, does not require ongoing protein synthesis, and is not triggered as a result of the ratio of nuclei to cytoplasm in embryonic cells that initiates the MBT. We therefore propose that a developmental timing mechanism measures an approximately 5-hr time period, from the time of fertilization, and then allows activation of a protein degradative pathway that regulates cyclin E1. Characterization of the timer suggests that it might be held inactive in eggs by a mitogen-activated protein kinase signal transduction pathway.

Identification of a developmental timer regulating the stability of embryonic cyclin A and a new somatic A-type cyclin at gastrulation.

We have identified a second Xenopus cyclin A, called cyclin A2. Cyclin A2 is a 46.6-kD protein that shows a greater homology to human cyclin A than to the previously identified Xenopus cyclin A1. It is present throughout embryonic development (up to stage 46 at least) and is found in adult tissues as well as in Xenopus tissue culture cell lines. In contrast, cyclin A1 is present in eggs and early embryos but cannot be detected in late embryos or in tissue culture cells. We have found that the maternally stored pools of mRNAs encoding both of these cyclin A proteins are stable until the onset of gastrulation and then are degraded abruptly. At this time, new transcription replaces cyclin A2 mRNA. Interestingly, we have also observed a dramatic change in the stability of the cyclin A proteins at this time. Prior to the onset of gastrulation, cyclin A1 protein is stable during interphase of the cell cycle. At gastrulation, however, both A1 and A2 proteins turn over rapidly during interphase of the cell cycle. Together, these results indicate that developmental programs controlling cyclin A protein and mRNA stability are activated at gastrulation. We have shown that this program is independent of new transcription beginning at the mid-blastula transition. Furthermore, treatment of early stage embryos with cycloheximide demonstrates that activation of this degradative program is independent of cell division and translation. Collectively, our observations suggest that a previously uncharacterized timing mechanism activates new degradative pathways at the onset of gastrulation, which could play an essential role in releasing cells from maternal programming.

Induction of the cell cycle in baby rat kidney cells by adenovirus type 5 E1A in the absence of E1B and a possible influence of p53.

From previous studies on the induction of DNA synthesis in quiescent primary baby rat kidney cells by adenovirus type 5 (Ad5) E1A deletion mutants, we concluded that induction is prevented only when cellular proteins p300 and pRb are both uncomplexed with E1A (J.A. Howe, J.S. Mymryk, C. Egan, P.E. Branton, and S.T. Bayley, Proc. Natl. Acad. Sci. USA 87:5883-5887, 1990). We have now examined induction by these same mutants in virus lacking the E1B region, so that cellular p53 was no longer complexed to the E1B 55-kDa protein. E1A mutants that fail to bind pRb induced DNA synthesis at a significantly lower level in Ad5 lacking E1B than in Ad5 containing E1B. Apparently, therefore, uncomplexed p53 can partially replace p300 in cooperating with pRb to suppress DNA synthesis in baby rat kidney cells.

Effects of Ad5 E1A mutant viruses on the cell cycle in relation to the binding of cellular proteins including the retinoblastoma protein and cyclin A.

We have examined the ability of Ad5 E1A 12S viruses with deletions in E1A exon 1 to induce quiescent baby rat kidney cells to progress through the cell cycle and to undergo mitosis. Measurements of mitotic index and analyses by fluorescence activated cell sorting were correlated with the abilities of the mutant E1A proteins to bind to cellular proteins. All the mutants induced cells to leave G0/G1 and enter S phase, but two groups were defective at inducing mitosis, and cells infected with them appeared to be blocked between the S and M phases. The first group of mutants, with deletions in the regions of residues 4-25 and 30-60, bound p300 poorly or not at all and gave reduced numbers of mitoses. The second group, with deletions between residues 111 and 138 in CR2, failed to bind pRb and were completely defective at inducing mitosis. In this group, mutants lacking residues between 124 and 138 bound p107 and cyclin A at much reduced levels and induced cells to overreplicate their DNA. The site in E1A required to bind cyclin A extends from residue 124 to at least 127. Cyclin A binds to a 107-kDa cellular protein, which by peptide analysis appears identical to p107.

Retinoblastoma growth suppressor and a 300-kDa protein appear to regulate cellular DNA synthesis.

Previous work has suggested that oncogenic transformation by the E1A gene products of adenovirus type 5 may be mediated through interactions with at least two cellular proteins, the 105-kDa product of the retinoblastoma growth suppressor gene (p105-Rb) and a 300-kDa protein (p300). By using viral mutants, we now show that the induction of cellular DNA synthesis in quiescent cells by E1A differs from transformation in that E1A products induce synthesis if they are able to bind to either p105-Rb or p300, and only mutant products that bind to neither are extremely defective. These results suggest that p105-Rb and p300 (or cellular proteins with similar E1A-binding properties) provide parallel means by which DNA synthesis can be regulated.

Sequences in E1A proteins of human adenovirus 5 required for cell transformation, repression of a transcriptional enhancer, and induction of proliferating cell nuclear antigen.

A range of deletion and other mutants in the coding region of the E1A gene of Ad5 has been assayed for transformation of baby rat kidney (BRK) cells in cooperation with ras, repression of the SV40 enhancer, and induction of proliferating cell nuclear antigen (PCNA). Transformation efficiency was drastically reduced by deletion of residues 4-25, 36-60, or 111-138 in exon 1 of the 289 residue (289R) and 243R E1A proteins. Deletion of other residues in exon 1 had little effect. With mutants in the region unique to the 289R protein, and in exon 2, the only effect on transformation seemed to be an increased tendency of mutant transformants, compared to wt, to migrate to form secondary foci. Repression assays, performed with E1A plasmids producing only the 243R protein, showed that deletion of residues 4-25 or 36-60 inhibited repression completely. Deletion of residues 128-138 reduced repression, but deletions elsewhere in exon 1 had little effect. Deletion of residues 188-204 in exon 2 reduced repression slightly, and deletion of all of exon 2 reduced it to about one-half. It is concluded that for transformation, there are two functional domains in E1A proteins, both in exon 1, both involved in binding different cellular proteins, and both probably concerned with different transforming functions. One of these domains, involving residues 4-25 and 36-60, also functions in repression, but the role of the second in repression is much less critical. All of the deletion mutants in exon 1 induced PCNA synthesis in BRK cells. This result, together with previously published work, suggests that the active site for PCNA induction either involves residues 61-69 or 82-85 in exon 1, which have not been deleted, or it does not depend on any single limited region of the E1A proteins.

Mapping of cellular protein-binding sites on the products of early-region 1A of human adenovirus type 5.

The binding sites for the 300-, 107-, and 105-kilodalton cellular proteins which associate with human adenovirus type 5 E1A products were studied with E1A deletion mutants. All appeared to bind to the amino-terminal half of E1A products in regions necessary for oncogenic transformation. These results suggest that these cellular species may be important for the biological activity of E1A products.

Use of deletion and point mutants spanning the coding region of the adenovirus 5 E1A gene to define a domain that is essential for transcriptional activation.

To help in identifying functional domains within Ad5 E1A proteins, we have constructed a series of mutants that create deletions throughout these products. We have also produced several mis-sense point mutations in the unique 13 S mRNA region. These mutated E1A regions have been tested in plasmid form for their ability to activate transcription of an E3-promoted CAT gene. From the results, a major domain for transactivation has been identified. This begins between residues 138 and 147, ends between residues 188 and 204, and encompasses the unique 13 S region. This domain is sensitive to mis-sense mutations. Transactivation was unaffected by small deletions in the N-terminal half of E1A proteins between residues 4 and 138, but was destroyed when this whole region was deleted. The C-terminal 71 residues may affect transactivation, but the results with the mutant in which this region was deleted were variable. The results obtained with these mutants are discussed in relation to the transactivation obtained by J. W. Lillie et al. [(1987). Cell 50, 1091-1100] with a synthetic peptide similar to the domain described here.

Community intervention with the elderly: a social network approach.

A technique is described for using the advantages of a social systems approach when working with elderly persons in psychiatric distress. The technique is based on the assumption that the solution to a variety of human predicaments lies within the collective instrumental and affective resources of the client's social network. The vehicle for accomplishing this objective is the "Network Session" during which a mental health professional meets with the elderly person and members of his/her social network to help resolve the difficulty. A case report demonstrating use of the technique is included.