pHG165: a pBR322 copy number derivative of pUC8 for cloning and expression

During the construction of the Messing pUC plasmid series, the rop(rom) gene of pBR322 which mediates the activity of RNAI was deleted. This has resulted in an elevated copy number for the pUC plasmids which makes the expression of beta-galactosidase activity constitutive in a host containing the Iqtss lac repressor. We describe the construction of a new series of vectors which retain the pUC multiple cloning site (MCS) but in which copy number control has been recovered. In addition, the lac alpha/lac promoter expression region has been inserted into a HpaI cassette. This facilitates the movement of recombinant DNA clones within the MCS. It also increases the complementation activity of the lac alpha peptide by an order of magnitude, allowing selection of recombinants by their Lac- phenotype on MacConkey agar.

Visual representation of eye gaze is coded by a nonopponent multichannel system

To date, there is no functional account of the visual perception of gaze in humans. Previous work has demonstrated that left gaze and right gaze are represented by separate mechanisms. However, these data are consistent with either a multichannel system comprising separate channels for distinct gaze directions (e.g., left, direct, and right) or an opponent-coding system in which all gaze directions are coded by just 2 pools of cells, one coding left gaze and the other right, with direct gaze represented as a neutral point reflecting equal activation of both left and right pools. In 2 experiments, the authors used adaptation procedures to investigate which of these models provides the optimal account. Both experiments supported multichannel coding. Previous research has shown that facial identity is coded by an opponent-coding system; hence, these results also demonstrate that gaze is coded by a different representational system to facial identity.

Activated protein C resistance (factor V Leiden) associated with thrombosis in pregnancy

OBJECTIVE

Our purpose was to evaluate activated protein C resistance phenotype and genotype among patients with thrombosis during pregnancy and the puerperium.

STUDY DESIGN

This observational study was conducted prospectively during a 2-year period (July 1993 to June 1995) in a preselected population. All patients admitted to our high-risk pregnancy unit with a diagnosis of deep vein thrombosis, pulmonary emboli, transient ischemic attack, and cerebrovascular accident during pregnancy and the puerperium were included. Prothrombin time, partial thromboplastin time, fibrinogen levels, protein C, protein S, antithrombin III, functional test for activated protein C resistance, and factor V Leiden mutation by polymerase chain reaction were performed on each patient.

RESULTS

Fifteen patients were included. Seven (46.6%) patients were positive for activated protein C resistance (factor V Leiden). All other coagulation studies were negative for all patients. All patients with activated protein C resistance had a venous thrombotic event, deep vein thrombosis, or pulmonary emboli, and only one had a cerebrovascular accident on the basis of sagittal sinus thrombosis. Only two of the activated protein C resistance-negative patients had venous thrombosis (pulmonary emboli). The remaining six patients had transient ischemic attacks or cerebrovascular accidents. For the subgroup with venous thrombosis during pregnancy and the puerperium, the incidence of activated protein C resistance (factor V Leiden) was 78%.

CONCLUSION

This study demonstrates the incidence of factor V Leiden in a selected population in whom thrombotic events developed during pregnancy and the puerperium. This small-scale study provides justification for a large cohort study that will identify women with factor V Leiden and determine their risk for thrombosis during pregnancy and the puerperium. We believe that factor V Leiden should be evaluated in conjunction with thrombotic events in the pregnant woman.

Specific DNA sequences associated with the nuclear matrix in synchronized mouse 3T3 cells

Eukaryotic chromatin appears to be organized into arrays of supercoiled loops anchored to the scaffolding structure of the mitotic chromosome core or to the nuclear matrix of interphase nuclei. To reveal whether specific DNA sequences are involved in this level of chromatin organization, we isolated and cloned a population of DNA molecules [average length of 150 base pairs (bp)] closely associated with the nuclear matrix after exhaustive DNase digestion and subsequent extensive protease digestion. The nuclear matrix was obtained from murine BALB/c 3T3 cells synchronized at the G1/S border of the cell cycle. We report the structure of two sequences, designated G4 and G5, which are highly enriched in the matrix DNA. Sequence G4, of 152 bp, contains three 31-bp direct head-to-tail repeats. An 11-bp sequence at the end of each repeat is homologous to the first large tumor antigen recognition site of human papova virus. Sequence G5, of 135 bp, consists of two well-defined domains, in which the first domain is a fragment of the B1 repetitive sequence. The results suggest the possibility that the loops of histone-depleted chromatin are connected to the scaffold of the nuclear matrix, with specific DNA sequences at the anchorage sites.

Urinary cytokeratin 20 as a marker for transitional cell carcinoma

OBJECTIVES

To determine if detection of cytokeratin 20 (CK20) gene expression, by reverse transcriptase-polymerase chain reaction (RT-PCR) in urine from transitional cell carcinoma (TCC) patients, can provide a new noninvasive tool for the follow-up of patients with urothelial carcinoma of the bladder.

METHODS

Urine was collected from 95 patients previously diagnosed as TCC during their follow-up, and from 27 healthy volunteers. All patients had a transurethal resection of tumor or biopsies obtained from 'suspicious' areas in the bladder. RNA was extracted from cells collected from the urine and RT-PCR was performed with specific primers for the amplification of cytokeratin 8, a general marker for epithelial cells, and of CK 20, a marker for TCC urothelium.

RESULTS

CK20 expression was detected in 86.7% of TCC patients, and only in 3.3% of healthy volunteers (specificity 96.7%). Strong correlation was found between tumor grade and expression of CK20 in urine. All grade III and IV tumors demonstrated positive CK20 expression (100% sensitivity), whereas the sensitivity for lower grades was between 71 and 80%. Among 11 patients with a previous biopsy-proven diagnosis of TCC and a current negative biopsy, in 9 patients CK20 expression was detected. Further follow-up of these patients for a period of 6 months revealed recurrence of TCC in 4 patients.

CONCLUSION

CK20 detection in urine cells is a simple, noninvasive method with a high potential to become the marker of choice for monitoring and follow-up of TCC patients. More information is needed regarding CK20 expression in nonmalignant urological disease, to evaluate its use for routine screening purposes.

High frequency of vitamin B12 deficiency in asymptomatic individuals homozygous to MTHFR C677T mutation is associated with endothelial dysfunction and homocysteinemia

The aim of this study was to examine the association of homozygosity for the methylenetetrahydrofolate reductase (MTHFR) C677T mutation and vitamin B12 deficiency in 360 asymptomatic individuals and to investigate forearm endothelial function in C677T homozygotes. MTHFR C677T mutation and levels of vitamin B12, folic acid, and homocysteine were measured in study participants. Frequency of homozygosity for the C677T mutation was 67/360 (18.6%). Homocysteine levels were elevated in homozygous compared with heterozygous subjects or those without the mutation (20.6 +/- 18.8 vs. 9.4 +/- 3.2 mumol/l; P < 0.0001). The number of subjects with vitamin B12 deficiency (<150 pmol/l) was significantly higher among the homozygote than the heterozygote subjects or subjects without mutation [20/67 (29.8%) vs. 27/293 (9.2%); P < 0.0001]. Homozygote subjects had 4.2 times higher probability of having B12 deficiency (95% confidence interval = 2.1-8.3). Forearm endothelial function was assessed in 33 homozygote and 12 control subjects. Abnormal endothelial function was observed in homozygous subjects and was worse in homozygote subjects with vitamin B12 deficiency. Endothelial function was normalized after B12 and folic acid treatment. We found that homozygosity for the C677T mutation is strongly associated with B12 deficiency. Coexistence of homozygosity for the C677T mutation and B12 deficiency is associated with endothelial dysfunction and can be corrected with vitamin B12 and folic acid treatment.

Effect of adherent cells on the regulation of BFU-E in patients with myeloproliferative disease

The interaction between adherent cells and red cell progenitors from peripheral blood of patients with polycythemia vera (PV), essential thrombocytosis (ET), and healthy controls was studied. Various combinations of adherent and nonadherent cells were co-cultured in a semisolid system. Adherent cells from controls, when added at low concentrations, stimulated BFU-E proliferation, whereas high concentrations (40% of total cells in the culture) caused a significant decrease in the number of BFU-E colonies in 6/8 PV patients, 4/4 ET patients, and 8/12 controls. On the other hand, low and high concentrations of adherent cells from both patients with PV and ET caused a significant increase in BFU-E from either patients or controls. Moreover, adherent cells from these patients induced endogenous BFU-E proliferation (independent of erythropoietin) in nonadherent cells of 12/12 normal controls. The results show that BFU-E from patients with PV and ET are sensitive to suppression by normal adherent cells. On the other hand, adherent cells from these patients possess stimulatory activity on BFU-E from peripheral blood at all concentrations and are devoid of the inhibitory activity. This suggests a possible defect in the functioning of adherent cells in PV and ET patients which may contribute to the abnormal regulation of hematopoiesis in these disorders.

Erythropoietin-independent colonies of red blood cells and leukocytosis in a worker exposed to low levels of benzene

BACKGROUND

Exposure to high levels of benzene commonly results in the suppression of hemopoiesis, although cases of leukocytosis and leukocytosis with thrombocytosis have been reported. No hematologic abnormalities have generally been found with exposure to low levels of benzene.

METHODS

A pipe fitter exposed to low levels of benzene (time-weighted average 0.9 ppm) developed leukocytosis. His blood counts and growth of erythroid burst forming units (BFU-E) was followed with and without the addition of erythropoietin.

RESULTS

Erythropoietin-independent BFU-E colonies were increased to 40 per 4 x 10(4) cells (normal < 3 per 4 x 10(4) cells). Both the leukocyte count and the number of erythropoietin-independent BFU-E colonies decreased when exposure to benzene was terminated. On reexposure the white blood count again increased. After the work was terminated, the white blood count returned to normal, as did the number of erythropoietin-independent BFU-E colonies, over a period of 12 months.

CONCLUSIONS

Our findings suggest that even low levels of benzene can result in perturbations of the hemopoietic system. Further studies are warranted to determine whether these findings are idiosyncratic, coincidental, or a more general phenomenon.

Exploring neuropsychological underpinnings of poor communication after traumatic brain injury: The role of apathy, disinhibition and social cognition

BACKGROUND

Dysarthria, aphasia and executive processes have been examined for their role in producing impaired communicative competence post traumatic brain injury (TBI). Less understood is the role of emotional dysregulation, that is, apathy and disinhibition, and social cognition, that is, reading and interpreting social cues.

METHODS & PROCEDURES

In this study, we examined 49 adults with moderate to severe TBI and 18 neurologically healthy adults. We hypothesised that apathy and disinhibition would predict communication outcomes as would social cognition. We also predicted that apathy and disinhibition would influence social cognition. Communication outcomes were measured by the La Trobe Communication Questionnaire (LCQ) and the Social Skills Questionnaire-TBI (SSQ-TBI). Apathy and disinhibition were measured by the Frontal Systems Behavior Scale (FrSBe). We measured four aspects of social cognition: emotion perception and theory of mind using The Awareness of Social Inference Test (TASIT) and the Complex Audio-Visual Evaluation of Affect Test (CAVEAT), empathy using the Questionnaire of Cognitive and Affective Empathy (QCAE) and the Balanced Emotional Empathy Scale (BEES), and alexithymia using the Toronto Alexithymia Scale (TAS-20) and the Bermond-Vorst Alexithymia Questionnaire.

OUTCOMES & RESULTS

Consistent with predictions, the LCQ and SSQ-TBI were associated with disinhibition and the LCQ was also associated with apathy. The LCQ was associated with the full range of social cognition constructs although the SSQ-TBI was not. Finally, apathy and disinhibition predicted a number of social cognition measures.

CONCLUSIONS AND IMPLICATIONS

These results are discussed in relation to understanding the nature of communication disorders following TBI and how they are measured, as well as the interrelation between emotion dysregulation and social cognition.

WHAT THIS STUDY ADDS

What is already known on this subject The role of emotional dysregulation and social cognition in producing impaired communicative competence post traumatic brain injury (TBI) is not well understood. Although most adults with severe TBI have minimal or possibly no language impairment, they often struggle with functional communication in everyday situations. Many have been reported to be overtalkative, insensitive, childish and self-centred, displaying an inappropriate level of self-disclosure and making tangential and irrelevant comments. Conversely, some speakers with TBI have been noted to have impoverished communication, producing little language either spontaneously or in response to the speaker's questions and prompts. What this paper adds to existing knowledge We found that both apathy and disinhibition were strongly associated with the Latrobe Communication Questionnaire both empirically and conceptually, despite the LCQ being developed from a different, pragmatic orientation. Disinhibition was also associated with the Social Skills Questionnaire for TBI. We also found that poor social cognition scores predicted communication difficulties. Finally, we found that behavioural dysregulation itself, i.e., both apathy and disinhibition, predicted poor social cognition. What are the potential or actual clinical implications of this work? Our findings highlight the central role that apathy and disinhibition play in both communication and social cognition. These insights point to the importance of remediation to target behavioural and autonomic dysregulation as a means to improve everyday social function.

Evidence for the existence of circulating monoclonal B-lymphocytes in multiple myeloma patients

Multiple myeloma is characterized by the proliferation of a single clone of plasma cells producing a homogeneous immunoglobulin fraction. In this disease, plasma cells home essentially in the bone marrow. However, controversy exists whether peripheral blood B-lymphocytes in patients with multiple myeloma (MM) are part of the malignant clone. We investigated clonal immunoglobulin gene rearrangement (IgGR) in T-cell-depleted peripheral blood mononuclear cells as well as in bone marrow of these patients. Seven out of 17 MM patients demonstrated an identical IgGR in bone marrow and peripheral mononuclear cells, these patients were in an active stage of the disease. In nine patients in plateau phase, clonal IgGR could not be detected in peripheral blood. Peripheral mononuclear cells from ten patients with monoclonal gammopathies of undetermined significance (MGUS) were also examined and no IgGR was detected. The existence of monoclonal B-lymphocytes in the circulation of patients with MM suggests a mechanism whereby the malignant clone homes in the bone marrow through peripheral blood. These findings may also be used for the evaluation of patients with active myeloma and the determination of plateau phase.

Soluble factors from peripheral blood T-cells of patients with polycythemia vera stimulate normal BFU-E

T cells and monocytes from patients with polycythemia vera (PV) were isolated and grown in culture. The conditioned medium was tested for the presence of soluble factors that promote proliferation of erythroid colonies from the blood of healthy donors. We show that T cells from all 14 PV patients that were examined secrete factor/s that stimulate the proliferation of erythroid burst-forming units (BFU-E) in the absence of an external source of erythropoietin and BPA. Addition of cyclosporin A to the culture did not inhibit the production of this activity. The conditioned medium from monocytes of PV patients can also stimulate normal BFU-E but to a much lesser extent than T-cell conditioned medium. Such stimulation was not observed with control T cells or monocytes. We observed that the fraction of DR-positive T cells was significantly higher in PV patients comparing to normal. These results suggest that PV patients possess an abnormally high level of circulating activated T cells which may in turn be the source of the putative factor that facilitates uncontrolled erythroid differentiation.

Telomerase activity and cytokeratin 20 as markers for the detection and followup of transitional cell carcinoma: an unfulfilled promise

PURPOSE

Telomerase activity compensates for the erosion of chromosomes and it has been detected in a wide variety of human tumors. Cytokeratin 20, an intermediate filament of epithelial cells, is expressed particularly in the urinary tract. These 2 molecules are candidates to become markers for the detection and followup of bladder carcinoma. We evaluate whether each molecule may serve as a potential marker and whether the 2 combined would improve the detection or followup of bladder carcinoma in a noninvasive manner.

MATERIALS AND METHODS

We obtained 44 morning urine samples from patients with transitional cell carcinoma patients and 26 from age matched patients with a wide variety of clinical disorders but no malignancy of any kind. A telomerase polymerase chain reaction-enzyme-linked immunosorbent assay kit was used to determine telomerase activity and cytokeratin 20 expression was determined by nested reverse transcriptase-polymerase chain reaction.

RESULTS

All samples tested positive for cytokeratin 8 expression, which verified epithelial cells in the urine samples. Of the 44 transitional cell carcinoma cases of all stages and grades 37 (84.1%) were positive for telomerase activity, 36 (81.8%) were positive for cytokeratin 20 expression and 65.9% were double positive. Of the 29 controls with various clinical conditions other that malignancy 22 (75.9%) were positive for telomerase activity, 13 (44.83%) were positive for cytokeratin 20 expression and 34.6% were double positive.

CONCLUSIONS

Telomerase activity and cytokeratin 20 expression are not specific for malignancy and may be detected in many nonmalignant pathological conditions. Therefore, their use as potential markers of bladder carcinoma should be carefully reevaluated.

The complex audio visual emotion assessment task (CAVEAT): development of a shorter version for clinical use

PURPOSE

The Complex Audio Visual Emotion Assessment Task (CAVEAT) is a measure of emotion recognition using dynamic, naturalistic videos to assess recognition of 22 different emotional states (11 positive, 11 negative). It has established construct validity and demonstrated sensitivity to emotion perception impairments in those with moderate-severe traumatic brain injury (TBI). Despite this, its lengthy administration has limited its use in clinical practice and rehabilitation. The current paper aimed to develop shortened versions of the CAVEAT and examine their psychometric properties.

METHODS

The CAVEAT-S A and CAVEAT-S B (22 items each) and the CAVEAT-S AB (44 items) were developed using the original data. Comparability, reliability, construct and predictive validity were examined in the original sample (Study 1: 32 people with TBI and 32 demographically matched control participants) and a replication sample (Study 2: 18 adults with TBI and 21 demographically matched controls).

RESULTS

All short forms produced comparable accuracy ratings to the full measure, as well as discriminating between people with or without a TBI. Shortened forms all correlated with other measures of emotion perception and social cognition and also predicted psychosocial outcomes in terms of self-reported interpersonal relationships. Internal reliability of the short forms was low relative to the longer forms, especially for the two very short measures.

CONCLUSIONS

The new shortened forms of the CAVEAT are promising tools that are sensitive and valid for assessing emotion perception in people with TBI for clinical purposes. Their application in other clinical disorders is yet to be examined.Implications for rehabilitationEmotion perception deficits are present in many clinical populations and an important target for rehabilitation.CAVEAT Short provides ecologically valid emotional stimuli. Such stimuli are important for assessing real world function and to set rehabilitation targets.By having parallel versions of CAVEAT, there is the opportunity to test pre and post intervention while minimising practice effects.Alternatively, one version of CAVEAT-S can be used for assessment, while the other is used for training purposes during remediation.

SIFT IT: A feasibility and preliminary efficacy randomized controlled trial of a social cognition group treatment programme for people with acquired brain injury

Making sense of social situations requires social cognitive skills, which can be impaired after acquired brain injury (ABI), yet few evidence-based treatment options are available. This study aimed to evaluate the feasibility of a multi-faceted social cognition group treatment programme, SIFT IT, for people after ABI using an RCT design. Twenty-eight participants were recruited, and 23 were randomized into either Treatment or Waitlist. SIFT IT consisted of 14 weekly 90-minute small group sessions facilitated by a Clinical Psychologist. Topics included: emotion self-awareness, emotion perception, perspective taking, and choosing adaptive social responses. Preliminary efficacy outcomes were assessed at baseline, post-treatment, and three-month follow-up. Demand for treatment was evident with 61% recruitment and 91% post-treatment retention rates, with 63% attending at least 13/14 sessions. Large between-group treatment effects (with non-zero 95% confidence intervals) were observed for emotion perception, detecting hints, and informant ratings of social cognitive deficits. Implementation challenges recruiting to groups and maintaining group allocation fidelity, with a small sample size does, however, raise questions about the appropriateness of an RCT design in a future efficacy trial. Overall, this study showed there is demand for social cognitive interventions after ABI and the SIFT IT programme was practicable and acceptable to participants.Trial registration: Australian New Zealand Clinical Trials Registry identifier: ACTRN12617000405314.

Retroviral-mediated gene transfer into CD34-enriched human peripheral blood stem cells

Retroviral-mediated gene transfer has been shown to be a feasible method for the introduction of new genes into bone marrow hematopoietic stem cells. We have investigated the application of this technology to primitive CD34-enriched human peripheral blood cells as a potential alternative stem cell source. Bone marrow (BM) and peripheral blood (PB) CD34-enriched cells from normal volunteers and patients with multiple myeloma were exposed to retroviral vectors containing the neomycin-resistance gene and gene transfer efficiency into colony-forming unit colonies (CFU-C) and CD34+ cells was assessed by polymerase chain reaction (PCR). Peripheral blood was a target equally efficient to BM, and PB cells mobilized with chemotherapy and growth factors were also shown to take up retroviral vectors readily. Conditions favoring gene transfer were investigated, and exposure of cells to interleukin-3 (IL-3), interleukin-6 (IL-6), and stem cell factor (SCF) during a 72-hour transduction was found to be most effective. The use of PB stem cells as targets for gene transfer could allow repeated collections and transductions, with obvious advantages over a single BM collection.