REDD2-mediated inhibition of mTOR promotes dendrite retraction induced by axonal injury

Dendritic defects occur in neurodegenerative diseases accompanied by axonopathy, yet the mechanisms that regulate these pathologic changes are poorly understood. Using Thy1-YFPH mice subjected to optic nerve axotomy, we demonstrate early retraction of retinal ganglion cell (RGC) dendrites and selective loss of mammalian target of rapamycin (mTOR) activity, which precede soma loss. Axonal injury triggered rapid upregulation of the stress-induced protein REDD2 (regulated in development and DNA damage response 2), a potent inhibitor of mTOR. Short interfering RNA-mediated REDD2 knockdown restored mTOR activity and rescued dendritic length, area and branch complexity in a rapamycin-dependent manner. Whole-cell recordings demonstrated that REDD2 depletion leading to mTOR activation in RGCs restored their light response properties. Lastly, we show that REDD2-dependent mTOR activity extended RGC survival following axonal damage. These results indicate that injury-induced stress leads to REDD2 upregulation, mTOR inhibition and dendrite pathology causing neuronal dysfunction and subsequent cell death.

Expression profiles of acute lymphoblastic and myeloblastic leukemias with ALL-1 rearrangements

The ALL-1 gene is directly involved in 5-10% of acute lymphoblastic leukemias (ALLs) and acute myeloid leukemias (AMLs) by fusion to other genes or through internal rearrangements. DNA microarrays were used to determine expression profiles of ALLs and AMLs with ALL-1 rearrangements. These profiles distinguish those tumors from other ALLs and AMLs. The expression patterns of ALL-1-associated tumors, in particular ALLs, involve oncogenes, tumor suppressors, antiapoptotic genes, drug-resistance genes, etc., and correlate with the aggressive nature of the tumors. The genes whose expression differentiates between ALLs with and without ALL-1 rearrangement were further divided into several groups, enabling separation of ALL-1-associated ALLs into two subclasses. One of the groups included 43 genes that exhibited expression profiles closely linked to ALLs with ALL-1 rearrangements. Further, there were evident differences between the expression profiles of AMLs in which ALL-1 had undergone fusion to other genes and AMLs with partial duplication of ALL-1. The extensive analysis described here pinpointed genes that might have a direct role in pathogenesis.

Effectiveness of targeted intervention and maintenance pharmacotherapy in conjunction with family intervention in schizophrenia

A sample of 85 patients with schizophrenia, of whom 34 later dropped out, received randomised treatment. There were no significant differences between treatment-takers and drop-outs in the variables assessed. Patients received either standard-dose maintenance neuroleptic treatment or targeted maintenance pharmacotherapy and all patients received behavioural family therapy. Measures of psychopathology, social adjustment, side-effects, family burden, and expressed emotion were assessed at baseline and then periodically over an 18-month period. The study was designed to compare the two alternative pharmacological maintenance approaches, each of them supported by psychosocial intervention. Any evaluation of the impact of behavioural family treatment on relapse rates and other outcome criteria is exclusively descriptive. A significantly higher rate of relapse was observed at 18 months in patients randomised to targeted treatment compared to those randomised to standard-dose treatment (35% vs 4%). Although patients assigned to the targeted maintenance group received significantly lower mean doses of neuroleptics, there were no significant differences between the two groups with regard to side-effects, global measures of social function, and overall psychopathology. Family burden was higher in the targeted-treatment group at six months, but did not differ at the one-year and eighteen-month time points. However, both groups improved significantly from baseline to 12 or 18 months in almost all variables assessed. Thus, the behavioural family approach did not compensate for the problems associated with the targeted medication strategy.

Upregulation of Meis1 and HoxA9 in acute lymphocytic leukemias with the t(4 : 11) abnormality

Rearrangements of the human ALL-1 gene are frequently encountered in acute lymphocytic leukemias (ALL) and acute myeloid leukemias (AML). These rearrangements are mostly due to chromosome translocations and result in production of chimeric proteins composed of the N-terminal fragment of ALL-1 and the C-terminal segments of the partner proteins. The most common chromosome translocation involving ALL-1 is the t(4 : 11) associated with ALL. ALL-1 is the human homologue of Drosophila trithorax and directly activates transcription of multiple Hox genes. A preliminary DNA microarray screen indicated that the Meis1, HoxA9 and AC133 genes were overexpressed in ALLs with t(4 : 11), compared to ALLs with very similar phenotype but without the chromosomal abnormality. These genes, as well as additional five Hox genes, were subjected to comprehensive semi-quantitative or quantitative RT-PCR analysis in 57 primary ALL and AML tumors. Meis1 and HoxA9 were found expressed in 13/14 of ALLs with the t(4 : 11) and in 8/8 of AMLs with ALL-1 rearrangements. The two genes were not consistently transcribed in other types of ALL. AC133 was transcribed in 13/14 of ALLs with t(4 : 11), but in only 4/8 of AMLs with ALL-1 rearrangements. HoxA10 was expressed in most leukemias with ALL-1 alterations, but was also transcribed in PrePreB CD10(-) ALLs lacking the t(4 : 11). Expression of HoxA5, HoxA7, HoxC8 and HoxC10 did not correlate with ALL-1 rearrangements. Coexpression of Meis1 and HoxA9, overexpression of HoxA10, and overexpression or fusion of HoxA9 were previously implicated in certain acute myeloid leukemias in mice and humans. The present work suggests that upregulation of Meis1, HoxA9, and possibly HoxA10 might also play a role in pathogenesis of acute lymphocytic and acute myeloid leukemias associated with ALL-1 fusions.

Stress-induced secretion of growth inhibitors: a novel tumor suppressor function of p53

p53 tumor suppressor gene controls cell response to a variety of stresses inducing growth arrest or apoptosis in damaged cells. It largely determines the sensitivity of tumor and normal cells to radiation and chemotherapy, and, therefore, defines both the efficacy and limitations of anti-cancer treatment. To determine molecular mechanisms of p53-dependent stress response in normal tissues we identified and compared the spectra of radiation-responsive genes in cells of different origin and p53 status using a cDNA array hybridization technique. The majority of genes identified were p53-dependent and cell type specific. Several of the new p53 responders encode known secreted growth inhibitory factors. This suggests that p53, in addition to its intrinsic antiproliferation activity, can cause 'bystander effect' by inducing export of growth suppressive stimuli from damaged cells to neighboring cells. Consistently, a p53-dependent accumulation of factors, which causes growth inhibitory effects in a variety of cell lines, was found after gamma irradiation in the media from established and primary cell cultures and in the urine of irradiated mice. Moreover, p53-dependent factors released by normal human fibroblasts potentiated the cytotoxic effect of a chemotherapeutic drug on co-cultivated tumor cells. This suggests a previously unknown role for normal cells in chemo- and radiation therapy of cancer.

DAP-kinase loss of expression in various carcinoma and B-cell lymphoma cell lines: possible implications for role as tumor suppressor gene

DAP-kinase is a novel calmodulin dependent serine/threonine kinase that carries ankyrin repeats and the death domain. It was recently isolated, by a functional selection approach of gene cloning, as a positive mediator of programmed cell death. In this study the expression of DAP-kinase was examined in the cell lines derived from various human neoplasms. DAP-kinase mRNA and protein expression were below the limit of detection in eight out of ten neoplastic derived B-cell lines. In six out of 14 examined bladder carcinoma, in three out of five renal cell carcinoma, and in four out of ten tested breast carcinoma cell lines, the DAP-kinase protein levels were below detection limits or lower than 1% compared to the positive cell lines. Interestingly, DAP-kinase expression could be restored in some of the negative bladder carcinoma and B-cell lines by treatment of cells with 5'-azadeoxycytidine that causes DNA demethylation. The high frequency of loss of DAP-kinase expression in human tumor cell lines, and the occasional involvement of methylation in this process raise the possibility that this novel mediator of cell death may function as a tumor suppressor gene.

DAP-kinase is a Ca2+/calmodulin-dependent, cytoskeletal-associated protein kinase, with cell death-inducing functions that depend on its catalytic activity

DAP-kinase was initially identified as a gene whose anti-sense-mediated reduced expression protected HeLa cells from interferon-gamma-induced programmed cell death. It was cloned in our laboratory by a functional gene selection approach. According to its amino acid sequence, this 160 kDa protein was predicted to be a novel type of calmodulin-regulated serine/threonine kinase which carries ankyrin repeats and the death domain. In this work we have shown that the kinase was autophosphorylated and capable of phosphorylating an exogenous substrate in a Ca2+/calmodulin-dependent manner. We proved that calmodulin binds directly to the recombinant kinase, and generated a constitutively active kinase mutant by the deletion of the calmodulin-regulatory domain. By immunostaining and biochemical fractionations we demonstrated that the kinase is localized to the cytoskeleton, in association with the microfilament system, and mapped a region within the protein which is responsible for binding to the cytoskeleton. Several assays attributed a cell death function to the gene. Ectopic expression of wild-type DAP-kinase induced the death of target cells, and the killing property depended strictly on the status of the intrinsic kinase activity. Conversely, a catalytically inactive mutant that carried a lysine to alanine substitution within the kinase domain, displayed dominant-negative features and protected cells from interferon-gamma-induced cell death. DAP-kinase is therefore a novel cytoskeletal-associated cell death serine/threonine kinase whose activation by Ca2+/calmodulin may be linked to the biochemical mechanism underlying the cytoskeletal alterations that occur during cell death.

Identification of a novel serine/threonine kinase and a novel 15-kD protein as potential mediators of the gamma interferon-induced cell death

Programmed cell death is often triggered by the interaction of some cytokines with their cell surface receptors. Here, we report that gamma interferon (IFN-gamma) induced in HeLa cells a type of cell death that had cytological characteristics of programmed cell death. In this system we have identified two novel genes whose expression was indispensable for the execution of this type of cell death. The rescue was based on positive growth selection of cells after transfection with antisense cDNA expression libraries. The antisense RNA-mediated inactivation of the two novel genes protected the cells from the IFN-gamma-induced cell death but not from the cytostatic effects of the cytokine or from a necrotic type of cell death. One of those genes (DAP-1) is expressed as a single 2.4-kb mRNA that codes for a basic, proline-rich, 15-kD protein. The second is transcribed into a single 6.3-kb mRNA and codes for a unique 160-kD calmodulin-dependent serine/threonine kinase (DAP kinase) that carries eight ankyrin repeats. The expression levels of the two DAP proteins were selectively reduced by the corresponding antisense RNAs. Altogether, it is suggested that these two novel genes are candidates for positive mediators of programmed cell death that is induced by IFN-gamma.

[Detection of early warning signs in schizophrenic patients. Possible applications in prevention of recurrence]

In the treatment of schizophrenia, two new strategies have been developed with the aim of adequate relapse prevention accompanied by lowest possible risk of side-effects. One strategy is to have the patient continue to take medication at a highly reduced dosage (10-20% of the standard dose). The other is to gradually stop neuroleptic medication after remission and to reinstitute medication only in the case of prodromal symptoms (termed targeted or intermittent treatment). According to Herz and Melville [13] many schizophrenic patients show signs of relapse well before recurrence of overt psychotic features. Monitoring to detect prodromal symptoms is especially important in targeted treatment because, otherwise, neuroleptic medication often cannot be initiated in time. In the present study of 51 schizophrenic patients we were able to replicate the results of Herz & Melville in the German-speaking countries. Prior to acute exacerbation of psychosis, most patients experience alterations of feelings and behaviour. These alterations may also be recognized by family members. Such early warning signs of relapse mainly consist of non-specific, non-psychotic symptoms: tenseness and nervousness, eating less, trouble concentrating and sleeping, depressive mood and seeing friends less. Furthermore, the regular monitoring and use of early warning signs specific to each patient in the aftercare of schizophrenic patients seems to be practicable, especially in psychoeducative family therapy.

Deliverability of psychoeducational family management

As part of an open clinical trial currently underway at the Max Planck Institute of Psychiatry in Munich, the feasibility of behavioral family management (Falloon et al. 1984) for schizophrenia in combination with two different neuroleptic medication strategies was investigated. The treatment approaches were psychoeducational family management with a standard dose or with targeted medication. In this article the following questions were addressed: (1) What proportion of the total schizophrenia population admitted as inpatients might be eligible for psychoeducational family treatment (assessment based on n = 411 over a 33-month period)? (2) How representative of this population are the patients who were randomized to the experimental groups? (3) How many patients dropped out of treatment after entering the trial? The results show that about 60 percent (247) of the patients were eligible for a psychoeducational treatment approach. Of these, 34 percent (85) participated in the trial and were randomized to the treatments. Only 4 percent of the relatives but 20 percent of the patients refused to take part in the study. The 85 trial patients did not differ from the total eligible on the numerous socioeconomic and symptom variables assessed. The treatment dropout rate was 11 percent. Those patients who accepted treatment did not differ from those patients who dropped out on socioeconomic or illness variables. The results indicate that early identification of dropouts is not possible at least with the methods used in this study.

Dependence of nucleic acid degradation on in situ free-radical production by adriamycin

Adriamycin (Adr) is one of the most powerful antitumor drugs. Its therapeutic effect may be due to its cyclic reduction-oxidation and, thus, generation of oxygen radicals. Using the spin-trap 5,5'-dimethyl-1-pyrroline N-oxide (DMPO) and EPR we have demonstrated that in an enzymatic system consisting of NADPH, NADPH-cytochrome P-450 reductase, and Fe(EDTA)2 Adr stimulates formation of .OH radicals in the presence of DNA or RNA with equal efficiency. Incubation of nucleic acids in the Adr-dependent reaction generating .OH radicals resulted in extensive degradation of double- and single-stranded DNA, but did not effect RNA. In contrast, both DNA and RNA were effectively destroyed in a footprinting system, ascorbate-Fe(EDTA)2-H2O2, which generates .OH radicals in massive quantities. Fluorescence assays indicated that Adr forms stable complexes with ds- and ss-DNA but reacts only slightly with RNA. We conclude that the formation of Adr-nucleic acid complex is necessary for .OH radical-mediated cleavage of the latter, and thus, Adr may be regarded as a chemical nuclease acting in situ.

Expression of the normal p53 gene induces differentiation of K562 cells

The multistep nature of human cancers is well illustrated by chronic myelogenous leukemia (CML), a clonal hematologic malignancy with two distinct phases: chronic and acute. Transition between these phases is characterized by unregulated growth and loss of differentiation of myeloid cells and their progenitors. We recently reported that loss of normal p53 expression correlates with transition from the chronic to acute phase in at least 25% of cases of CML. However, the precise relationship between this loss and biologic features of acute-phase CML is uncertain. To study this question, we artificially expressed normal p53 in K562, an erythroid acute-phase CML cell line lacking normal p53 expression. Biological effects were assessed by determining several growth parameters and by measuring synthesis of hemoglobin, a feature of mature erythroid cells. K562 cells expressing normal p53 had an increased proportion of cells in G1 versus S + G2, a longer doubling time and a lower growth saturation density than control K562 cells or K562 cells with antisense p53. Cells with normal p53 also expressed up to 50-fold more hemoglobin than controls. These data are consistent with the notion that loss of p53 expression may be responsible for many of the features of acute-phase CML cells. The data also demonstrate direct involvement of p53 in differentiation processes.

Balloon expandable stents to treat central venous stenoses in hemodialysis patients

Vascular access failure in hemodialysis patients remains a significant problem. The use of thrombolytic agents and balloon angioplasty instead of or in conjunction with surgical revision, has been helpful in increasing the life span of vascular access in these patients. The application of newer endovascular therapies, such as vascular stents, may further improve the salvage rate of hemodialysis access sites. These stents may be particularly valuable in treating stenoses in large central veins. We present 2 cases in which a balloon-expandable Palmaz stent was used to treat a central venous stenosis causing signs of vascular access failure.

Cross-national reliability, concurrent validity, and stability of a brief method for assessing expressed emotion

The Five-Minute Speech Sample (FMSS; Magana et al., 1986) is a brief method designed to assess the "expressed emotion" (EE) status of a respondent. The FMSS-EE rating is derived from statements made by a patient's key relative during a 5-minute monologue, with codes similar to those used in the original EE rating system (e.g., criticism and emotional overinvolvement). Rating is done from the audiotape and takes about 15-30 minutes. The article reports on the results of a cross-national study carried out in Germany using the FMSS with a sample of 60 relatives of schizophrenic patients. Results indicated that (1) German investigators could readily learn the system and could achieve a high degree of interrater reliability; (2) the association with the original index of EE, the Camberwell Family Interview, was comparable to that found by Magana et al.; and (3) the method yields very stable data over a 4-5 week retest period.

p53 in chronic myelogenous leukemia in acute phase

All patients with chronic myelogenous leukemia (CML) undergo clinical transition from chronic to acute phase. This transition is often associated with deletion of the short arm of chromosome 17 in the form of the i(17q) aberration. Since the p53 gene is a suppressor gene and is located on 17p13, we examined the possibility that it is inactivated during progression of CML. Therefore, we studied the structure and expression of p53 in the leukemic cells of a large number of CML patients in acute phase. We found that although the gene is rarely rearranged, one p53 allele is completely deleted in patients with the i(17q) aberration as well as in some patients who do not show karyotypic changes. In all of these patients the remaining allele is inactivated through loss of expression, rearrangement, or point mutation. Detailed analysis of some patients who carry both p53 alleles indicated neither loss of expression nor structural alterations. It appears that p53 loss of function is associated with progression of around 25% of CML patients.

Process analysis in behavioral family therapy

Process research in behavioral family therapy (BFT) is a hitherto neglected area with the notable exception of the work of Alexander and Patterson with their colleagues. However, the development of instruments to assess therapist's behavior during the treatment session seems timely for the following reasons: (a) to investigate the relationship between therapist behavior and outcome, (b) to improve therapist training/supervision, (c) to establish treatment integrity in comparative outcome studies, and (d) to monitor treatment progress. For these purposes two sets of instruments were developed: (a) a category system to describe the content of a session, which is rated every 30 seconds and (b) several rating scales to evaluate therapist behavior, including relationship competency, ability to structure a session, didactic competence, ability to initiate behavioral probes, use of appropriate intervention strategies, use of reinforcement, and dealing with uncooperativeness. Scales are described, and data on their reliability and utility are presented.

Measuring the instructional validity of clinical simulation problems

Written clinical simulation problems in two formats--forced-choiced and essay--were used to test junior and senior medical students at the conclusion of their pediatric rotations. A comparison was made in the performance of students with varying levels of clinical experience. There seemed to be no consistent pattern of improvement with increased instructional time on the forced-choice management problems. Junior students did show improvement over time on the essay management problems, which also seemed to reflect the increased problem-solving and organizational skills of seniors in comparison to juniors. Correlations across problems and correlations between the clinical problem test and other measurement techniques were very weak, partly due to the low sampling reliability of clinical simulation problems. In this study, clinical simulation problems failed to demonstrate responsiveness to development and maturation in the problem-solving approach to patient care.

Impact of student ratings on basic science portion of the medical school curriculum

Student opinion questionnaires used by the Office of Research in Medical Education (ORME) at the University of Texas Medical Branch (UTMB) as one source of evaluating the curriculum established in 1970 revealed widespread dissatisfaction with many of the courses. Concern over student dissatisfaction and poor performance on both internal and external measures of achievement led to the inauguration of student ratings. With the aid of the ORME in developing questionnaires, interpreting sources of student difficulty, and providing consultation to course directors and faculty, most of the faculty eventually accepted the ratings. As a result, improvements in instruction and evaluation were brought about which increased student satisfaction with courses and improved scores on internal, statewide, and national examinations.