[Magneto-encephalographic (MEG) brain recordings during traumatic memory recall in women with post-traumatic stress disorder: A pilot study]. / Enregistrement magnéto-encéphalographique (MEG) de réminiscences du trauma chez des femmes souffrant de stress post-traumatique : une étude pilote.

AIM OF THE STUDY: The experiment studied the effects of a short duration exposure to traumatic memories using magneto-encephalography (MEG). PATIENTS: Nine right-handed DSM-4 PTSD patients were recruited from a unit for anxiety disorders and an organisation supporting victims of violence. In order to have a homogeneous sample, we included only women who suffered from civilian PTSD. Exclusion criteria were co-morbid major medical illness, metallic dental prostheses that would interfere in the magnetic measurement, and current drug treatment. All participants were free from neurological disease and had normal hearing. They signed a written informed consent form. An ethics committee accepted the study. METHOD: A tape-recorded voice administered a script-driven imagery. The patients had to imagine, successively, a neutral image, a traumatic memory and rest, while MEG measured brain activities across delta, theta, alpha and beta bands. Each condition lasted three minutes. Heart rate (HR), anxiety and the vividness of mental images were recorded at the end of each phase. MEG power analysis was carried out with Statistical Parametric Mapping (SPM) 8. The signals were averaged for each of the three conditions of threeminutes duration. The dependent variable was a subtracted value: (trauma - rest) - (neutral - rest). The significance threshold was set at P<0.01. RESULTS: Anxiety and HR significantly increased during the trauma condition and returned to the neutral level during rest. The vividness of the mental imagery remained stable across the three conditions. The left-brain demonstrated a statistically significant power decrease in the secondary visual cortex (BA 18-19) in the delta band, the insula (BA13) in the beta band, the insula (BA13), premotor cortex (BA 6), Broca area (BA 44), and BA 43, in the alpha band. DISCUSSION: The symptom provocation protocol was successful in eliciting subjective anxiety and HR response in relation to traumatic memories. Our MEG results are in keeping with previous neuro-imagery studies showing decreased activities in the insula and Broca area during PTSD symptom provocation. However, we did not replicate the activation in the amygdala and the cingulate and prefrontal cortex found in some studies. Moreover, the within-group design, the small sample, and the inclusion of only female patients with milder dissociative symptoms limit our conclusions. The MEG protocol we used may also explain some partial discrepancies with previous MEG studies. However, our aim was to provoke a specific autobiographic recall of a traumatic event unfolding several sequential mental images along three minutes as in exposure therapy for PTSD. CONCLUSION: Despite its limitations, this pilot study is the first to provide MEG data during trauma recall. It suggests that recalling a specific traumatic event along three minutes results in hypo-activations of the brain regions regulating language and emotions. This paves the way to recording whole sessions of specific therapies for PTSD, with MEG using the millisecond resolution. MEG might be of interest to study the suppression of traumatic memories and their activation and habituation through prolonged graduated exposure in imagination across several sessions. MEG could also be used to study the effects of medication on PTSD symptoms. A controlled replication in a larger sample including male and female patients with various traumatic experiences is needed.

[Post-traumatic stress disorder in an anxiety disorder unit and in a victims support association]. / Etat de stress post-traumatique dans une unité de traitement de l'anxiété et dans une association d'aide aux victimes.

The post-traumatic stress disorder (PTSD) represents an original and frequent pathological entity concerning people confronted with one or more significant traumatic events. We present here a comparative study concerning subjects who present a post-traumatic stress disorder received in an anxiety disorder unit (ADU) or in a victims support association (VSA). One hundred and twenty seven people have been included in the study, according to DSMIV for PTSD, during three years. Fifty-seven came from a victim support association, 54 came from an anxiety disorder unit and 16 were common to both structures. The PCL-S (PTSD Checklist Scale) was used to rate the intensity of the PTSD. Age, sex, marital statute, type of traumatism, comorbidity and previous traumatisms were compared. PCLS scores were equivalent in the two settings. More women, younger subjects and more aggression were received in the victim support association. In the anxiety disorder unit more psychiatric comorbidity and more frequent antecedents of traumatism were seen. In the whole sample, two thirds of the people lived alone. Our results show that a victim support association receives people suffering from a definite post-traumatic stress disorder as intense on the PCL-S as in an anxiety disorder unit. More work has to be done on support association in the community, as they are confronted with significant PTSD problems.

[Evaluation of Post-traumatic Stress Disorder: validation of a measure, the PCLS]. / Evaluation des états de stress post-traumatique: validation d'une échelle, la PCLS.

Post-Traumatic Stress Disorder (PTSD) is a psychiatric disorder frequently found in psychiatric clinic and in the population of victims of traumatic events. PTSD, characterized by an intense fear, helplessness or horror, resulting from exposure to a traumatic event, is clinically manifested with three main syndromes: reexperiencing, avoidance behavior and numbing of emotion, and physiological hyperarousal. The Post-Traumatic Checklist Scale (PCLS) is a brief and self-report questionnaire for evaluating the severity of three main syndromes of PTSD. The scale can be divided into three sub-scores corresponding to the three main syndromes of the disorder: reexperiencing (items 1-5), avoidance (items 6-12) and hyperarousal (items 13-17). The validation studies in English version (Weathers et al., 1993, Blanchard et al., 1996) and French version (Ventureyra et al., 2001) showed that the PCLS possesses good psychometric properties. But the discriminating validation with another pathological group and the sensitivity of the scale to change of treatment have not yet been studied up to now. The aim of this study is the validation of the French version of the PCLS in Post-Traumatic Stress Disorder (PTSD) subjects compared with subjects suffering from other anxiety disorders and non-clinical subjects. The sensitivity of the PCLS after a cognitive behavioral therapy (CBT) for PTSD was studied for the first time. Fifty-seven outpatients suffering from PTSD according to DSM IV criteria, 23 patients suffering from other anxiety disorders and 28 non-clinical subjects were included in this study. All subjects were assessed with the PCLS. The Beck Depression Inventory--13 items (BDI-13) and the Fear Questionnaire (FQ) were used for the two groups of patients. Fifty-five PTSD patients were administered the PCLS twice over an interval of one to two weeks without any intervention in order to determine the test-retest reliability of the PCLS. And 24 PTSD patients were reassessed with the PCLS after 16 sessions of cognitive behavioral therapy (CBT) in order to study the sensitivity to treatment of the PCLS. The CBT technique for PTSD consisted of relaxation, exposition, recital, cognitive restructuration and stress management. The total score and the subscores on the PCLS were found to be significantly higher in PTSD patients than in two control groups: suffering from other anxiety disorders subjects (61.2/41.4, p<0.0001) and non-clinical subjects (61.2/28.8, p<0.0001). The correlation between the PCLS total score and the others measures showed that the PCLS correlated significantly with the depression measure, the BDI-13 (p<0.001), and the sub-scores of Fear Questionnaire (agoraphobia: p<0.001; anxiety-depression: p<0.001; distress: p<0.001), but not with the social phobia sub-score of the FQ. The PCLS showed a satisfactory test-retest reliability in 55 patients (the total score: r=0.75, p<0.0001; the sub-score of reexperiencing: r=0.844, p<0.0001; the sub-score of avoidance: r=0.702, p<0.0001; the sub-score of hyperarousal: r=0.712, p<0.0001). The t-test showed that the total score of the PCLS was significantly reduced in 24 patients after 16 sessions of CBT (the mean gain=13.1, t=5.63, p<0.0001). The results of our study confirm that the PCLS possesses good empirical and discriminating validity and a good sensitivity. The fact that the PTSD patients reported significantly higher total scores on the PCLS and its three subscores than other anxiety disorder subjects and non-clinical subjects indicates that the PCLS differentiates well the patients presenting PTSD from other anxiety disorder subjects and non-clinical subjects. The PCLS total score also correlates significantly with the other measures of psychopathology used in the study, such as measures of phobia (the Fear Questionnaire agoraphobia subscale), depression (the Beck Depression Inventory -13) and distress (the Fear Questionnaire distress subscale). This may be explained by the fact that some PTSD symptoms overlap with those of depression and of anxiety or phobia. The PCLS showed anxiety or phobia. The PCLS showed a satisfactory test-retest reliability. The PCLS is therefore a valid and effective measurement of PTSD. It may be a useful tool for screening and assessing PTSD in clinical practice and research in psychiatry.

[Inferiority in normal and anxious populations]. / Le sentiment d'infériorité entre population normale et anxieuse.

BACKGROUND: The construct of inferiority can be defined as an intimate, unrealistic and persistent conviction to be always low-ranking in merit, value, intellectual and/or physical capacities (Weiner et Mohl, 1996; Yao et al., 1996). This can be considered as an important cognitive factor in anxiety disorders. But, does a feeling of inferiority also exist in normal subjects? We hypothesized that the feeling of inferiority might be a normal phenomenon if it is a transient experience, in relation to external events, and represents an aspect of self esteem. The Inferiority Scale (Yao et al., 1998), aimed at measuring the feeling of inferiority in anxiety, is a self-report instrument including 17 items assessing self-appraisal of inferiority and 17 items assessing inferiority linked to others' judgements. It showed good psychometric properties of reliability and validity in previous studies. The aim of our study was to confirm the existence of inferiority feeling in non-clinical subjects, and its continuity between normal and anxious populations. Method - We included 264 non-clinical subjects in the study. The mean age of the sample was 30.38 years old (SD=10.25) and 36% (94 Ss) were men. The anxious population was composed with 57 subjects suffering from obsessive compulsive disorder (OCD) and 43 patients with social phobia according to DSM IV. The mean age of this population was 34.0 years old (SD=10.6) and 51% of them were men. The Inferiority Scale was used in our study for evaluating the feeling of inferiority. RESULTS: Most of non-clinical subjects reported low inferiority feelings and a part of the non-clinical subjects (15%) presented a moderate or strong feeling of inferiority, on the Inferiority Scale. The non-clinical subjects group was divided into two sub-groups (Low and High Inferiority) with the median of the Inferiority Scale total score. The total score and the sub-scores of the Inferiority Scale were all significantly higher in the two anxiety groups than in the two non-clinical sub-groups (p<0.0001) and higher in non-clinical subjects with high inferiority, compared to those with low inferiority (p<0.0001). Noting that the social phobic group presented higher scores of the Inferiority Scale than the OCD group (p=0.0058). There was a significant and negative correlation between age and the Inferiority Scale in non-clinical subjects, but there was no between-sex difference on the scale. CONCLUSION: Our results confirm the existence of inferiority feeling in non-clinical subjects and suggest the existence of continuity of inferiority feeling as a psychological trait between normal and pathological populations.

Personality dimensions in social phobics with or without depression.

OBJECTIVE: This study investigated the personality traits of social phobics using the Temperament and Character Inventory (TCI). METHOD: A sample of 178 social phobics was assessed with the TCI, and compared with controls. The patients were classified into two groups, according to the absence (SP group) or to the presence (SP+D group) of depression. RESULTS: We found significant elevated scores for harm avoidance (HA) in social phobics when compared with controls (16.2 +/- 2.7), in both the SP (26.2 +/- 3.5), and the SP+D (28.9 +/- 4.7), groups. Lower self-directedness scores were found in the SP and in the SP+D groups when compared with the controls. Patients with the generalized type of social phobia had higher HA scores as compared with other social phobics. CONCLUSION: The personality profile obtained in these social phobics, whatever their depressive symptomatology, reflects a dramatically anxious and avoidant temperament associated to an immature character.

A randomized controlled trial of cognitive therapy versus intensive behavior therapy in obsessive compulsive disorder.

BACKGROUND: The study was designed to compare cognitive therapy (CT) with intensive behavior therapy (BT) in obsessive-compulsive disorder (OCD) and to study their change process. METHODS: Sixty-five outpatients with DSM-4 OCD were randomized into 2 groups for 16 weeks of individual treatment in 3 centers. Group 1 received 20 sessions of CT. Group 2 received a BT program of 20 h in two phases: 4 weeks of intensive treatment (16 h), and 12 weeks of maintenance sessions (4 h). No medication was prescribed. RESULTS: Sixty-two patients were evaluated at week 4, 60 at week 16 (post-test), 53 at week 26 and 48 at week 52 (follow-up). The response rate was similar in the 2 groups. The Beck Depression Inventory (BDI) was significantly more improved by CT (p = 0.001) at week 16. The baseline BDI and Obsessive Thoughts Checklist scores predicted a therapeutic response in CT, while the baseline BDI score predicted a response in BT. At week 16, only the changes in Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) and a scale measuring the interpretation of intrusive thoughts correlated in CT, while the changes in Y-BOCS, BDI, and interpretation of intrusive thoughts correlated in BT. Improvement was retained at follow-up without a between-group difference. The intent-to-treat analysis (last observation carried forward) found no between-group differences on obsessions, rituals and depression. CONCLUSIONS: CT and BT were equally effective on OCD, but at post-test CT had specific effects on depression which were stronger than those of BT. Pathways to improvement may be different in CT and BT. The outcomes are discussed in the light of an effect size analysis.

Cognitive behavior therapy versus supportive therapy in social phobia: a randomized controlled trial.

BACKGROUND: The efficacy of cognitive behaviour therapy (CBT) in social phobia has been demonstrated in several controlled trials and meta-analyses, but no comparison of CBT with supportive therapy (ST) can be found in the literature. METHOD: The aim of the trial was to study the effectiveness of CBT versus ST carried out 'as usual'. Sixty-seven DSM-4 social phobic patients (89% generalized subtype, most with avoidant personality) were randomly allocated into two groups. Group 1 (CBT) received 8 1-hour sessions of individual cognitive therapy (CT) for 6 weeks, followed by 6 2-hour sessions of social skills training (SST) in group weekly. Group 2 received ST for 12 weeks (6 half-hour sessions), then the patients were switched to CBT. All patients agreed not to take any medication during the whole trial. In group 1, 29 patients reached week 6, 27 reached week 12, and 24 weeks 36 and 60 (endpoint). In group 2, 29 patients reached week 6, 28 reached weeks 12 and 18, 26 week 24, and 23 reached weeks 48 and 72 (endpoint). RESULTS: At week 6, after CT, group 1 was better than group 2 on the main social phobia measure. At week 12, after SST, group 1 was better than group 2 on most of the measures and demonstrated a significantly higher rate of responders. This finding was replicated after switching group 2 to CBT. Sustained improvement was observed in both groups at follow-up. Compliance with abstinence from medication increased over time. CONCLUSIONS: CBT was more effective than ST and demonstrated long-lasting effects. This may suggest that social phobia management requires more than a simple and inexpensive psychological intervention.

[Social anxiety in patients with social phobia: validation of the Liebowitz social anxiety scale: the French version]. / L'anxiété sociale chez les phobiques sociaux: validation de l'échelle d'anxiété sociale de Liebowitz (version française).

The Liebowitz's Social Anxiety Scale (LSAS) (Liebowitz, 1987) is a rating scale of fear and avoidance in social interaction (12 items) and performance-oriented situations (12 items). This paper present the study of empirical and concurrent validation of the LSAS. Ninety-six patients suffering from social phobia according to DSM IV were included and compared with 64 non-clinical control subjects. Both patients and controls were divided into two sub-groups: the LSAS passation by hetero-evaluation or auto-evaluation. Social phobics had much higher scores on anxiety and avoidance of the LSAS than control subjects, whatever the method. There were no differencies between hetero and auto-evaluation in both groups of patients and non-clinical subjects, either on anxiety or on avoidance. The LSAS correlated better with social anxiety and negative cognition in social situations than with anxiety-depression in social phobics. The French version of the LSAS showed a good empirical and concurrent validity and the scale presents a good sensitivity to change after cognitive behavioral therapy in social phobics.

[A controlled study of irrational interpretations of intrusive thoughts in obsessive-compulsive disorder]. / Une étude contrôlée sur les interprétations irrationnelles des pensées intrusives dans les troubles obsessionnels compulsifs.

UNLABELLED: Recent research suggested that the irrational interpretations of intrusive thoughts might be cognitive structures underlying obsessive compulsive disorder (OCD). We present a study on intrusive thoughts and their interpretations in 36 patients suffering from OCD (DSM IV criteria), compared with 36 sex and age matched non clinical subjects, with the Intrusive Thoughts and their Interpretations Questionnaire-revised version (ITIQ-r). This questionnaire measures intrusive thoughts intensity and three types of interpretation: responsibility, guilt and inferiority. The measures of OCD, of depression, of social phobia and of anxiety have been used. RESULT: OCD patients reported more frequent intrusive thoughts and higher irrational interpretations than controls. The higher the intrusive thoughts, the higher the irrational interpretations. The multiple regression showed that both intrusive thoughts and irrational interpretations were respectively predicted by obsessional compulsive pathology (the Obsessive Thoughts Checklist or the Y-BOCS). The Y-BOCS was the only predictor for inferiority interpretation, but there was no significant predictor for responsibility or for guilt interpretations. Responsibility correlated only with aggressive intrusive thoughts. Guilt was related to intrusions about fear of loss. Inferiority was highly correlated with intrusive thoughts about perfectionism and sexuality.

Validation of the French translation of the agoraphobic cognitions questionnaire.

BACKGROUND: The goal of the present study was to validate the French version of the Agoraphobic Cognitions Questionnaire (ACQ). METHODS: Subjects consisted of 115 patients with panic disorder and agoraphobia, 54 obsessive-compulsive patients and 72 normal controls. Patients were referred for outpatient treatment. They filled in the questionnaire before and after entering treatment. The control group consisted of people taken from the general population. It was matched with the clinical groups on age, sex and education. RESULTS: The ACQ appears to have a constant factor structure across US, Dutch and French samples. Results support the validity of the total score of the ACQ. Patients with panic disorder and agoraphobia scored significantly higher than obsessive-compulsive patients and control subjects. On the ACQ physical concerns subscale agoraphobic patients were significantly different from obsessive-compulsive patients and control subjects. On the social/behavioural subscale agoraphobic patients and obsessive-compulsive patients were significantly different from control subjects. The French translation of the ACQ was found to be stable over an interval of 15 days in the control group. The Cronbach coefficients of both subscales were also satisfactory. These results support the stability and the internal consistency of the questionnaire. In addition, the French translation of the ACQ was sensitive to changes with cognitive-behavioural therapy. CONCLUSIONS: These results support the findings of Chambless and Gracely [Cogn Ther Res 1989;13:9-20]. The ACQ physical concerns subscale is a specific feature for the anxiety status experienced by patients with panic disorder and agoraphobia. The ACQ social/behavioural subscale seems to be a more general feature of anxious patients.

Construction of human factor IX expression vectors in retroviral vector frames optimized for muscle cells.

Development of a highly refined human factor IX (hFIX) expression vector system is critical for establishing a durable hemophilia B gene therapy. Here we report construction of a series of retroviral vectors and identification of an optimal basic structure and components for expressing hFIX in skeletal muscle cells. These vectors, which are derived from Moloney murine leukemia virus (MoMLV) with its enhancer sequence in the 3' long terminal repeat (LTR) deleted, contained internal hFIX expression units inserted in forward configuration without or with a viral vector intron sequence (pdL or pdLIn vector frame, respectively) or in inverted configuration without a viral vector intron sequence (pdLi frame). Internal expression units contained a hFIX cDNA or hFIX minigene (hIXm1 or hIXm2) derived from the hFIX cDNA by insertion of a shortened first intron sequence of the hFIX gene. Regardless of the promoter and vector frame used, both hIXm1 and hIXm2 gave 10- to 14-fold higher hFIX expression compared to those with hFIX cDNA. Internal hFIX transcriptional control units of these vectors were composed of various promoters linked with or without the muscle creatine kinase enhancer (Me) sequence. Promoters tested included those of alpha-actin (alpha A775), beta-actin (beta A280), cytochrome oxidase (CO1250 and CO650), myogenin (Mg1031 and Mg353), and Rous sarcoma virus (RSV). beta A200, which was derived from beta A280 by eliminating potential polyadenylation sites, was also tested. As extensively examined with the myogenin promoter, presence of one or multiple copies of Me in the vectors elevated the expression activity in myotubes by 4.5- to 19-fold over those without Me, but not significantly in myoblasts. Similar enhancements in expression activity with Me were also observed with other promoters, except those of RSV and CO. The latter two showed only modest enhancements in the presence of Me. As assayed with myotubes in culture, the general order of hFIX expression activity of various promoters with four copies of Me in the three different vector frames was beta A280 approximately beta A200 > Mg353 > Mg1031 approximately RSV approximately CO650 approximately alpha A775 > CO1250. One exception was that CO650 showed significantly less activity in pdLi-type vectors than in the pdLIn vectors. Based on the systematic analyses of various structural components, a group of pdLi vectors consisting of beta A200, two to four copies of Me, and hIXm2 was identified to have the optimal basic vector structure to be used in retrovirus for hFIX expression in differentiated skeletal muscle cells. The present studies provide the critical first step for establishing a highly refined hemophilia B gene therapy based on skeletal muscle-targeted hFIX gene transfer.

Loss of expression of a retrovirus-transduced gene in human keratinocytes.

Retroviral-mediated transfer of new genetic information into keratinocytes is a key step in epidermal gene therapy. An obstacle to the use of retroviruses for gene therapy is that although high levels of expression of the transduced gene can be maintained in tissue culture, expression is often lost when the cells are transplanted to an animal host. To examine some of the factors involved in this instability of expression, we transduced keratinocytes with a retrovirus encoding the gene for human factor IX and monitored secretion of the transduced gene. We observed continued secretion of factor IX through five passages in culture. When, however, sheets of these cells were grafted to athymic mice, factor IX expression was reduced or lost within 6 wk. We show that the reduction of factor IX expression in grafted keratinocytes did not result from a loss of grafted cells, nor was there a block to systemic delivery of a secreted endogenous product.

Adenovirus-mediated transfer of human factor IX gene in immunodeficient and normal mice: evidence for prolonged stability and activity of the transgene in liver.

Recombinant adenovirus has recently become a promising gene delivery vehicle that may be used therapeutically for various medical disorders. However, in vivo expression of transgenes delivered by E1 region-deleted adenoviral vectors is transient in immunocompetent animals. It has been proposed that destruction of adenovirally transduced cells by the host immune mechanisms, particularly cytotoxic T-lymphocytes, may play a major role in limiting the duration of transgene expression in vivo. In the present study, Southern blot analysis of genomic DNA prepared from transduced liver tissues showed the persistent presence of the viral genome in both immunocompetent and immunodeficient animals, indicating the survival of the adenovirally transduced liver cells. Furthermore, active expression of the surviving factor IX transgenes was shown by the presence of recombinant human factor IX as well as specific human factor IX mRNA and protein in the transduced liver tissues. The transient appearance of human factor IX in the circulation of normal as well as partially immunodeficient mice is primarily due to the generation of mouse antihuman factor IX antibodies in these mice rather than host immune destruction of transduced cells. These results suggest that liver cells transduced with recombinant adenoviral vectors can escape from being destroyed by the host immune mechanism in normal animals. The present study thus provides a new rationale for further engineering of adenoviral vectors into a durable expression system for gene therapy of various diseases including congenital disorders such as hemophilia B.

Primary myoblast-mediated gene transfer: persistent expression of human factor IX in mice.

Primary myoblast-mediated gene transfer was tested for its ability to mediate a persistent expression of recombinant human factor IX in SCID mice. Mouse primary myoblasts were transduced with factor IX retroviral vectors, LIXSN, which uses the retroviral long-terminal repeats as the promoter, or dLMMBAIX, which uses muscle creatine kinase enhancer and beta-actin promoter to drive factor IX transcription. In vitro, myoblasts transduced with either LIXSN or dLMMBAIX expressed recombinant human factor IX with full biological activity. Upon implantation of transduced myoblasts into skeletal muscles of SCID mice, a sustained systemic expression of factor IX at a level of 10-30 ng/ml plasma was achieved. This was further supported by the presence of recombinant factor IX protein and mRNA in muscle tissues after 5 months of myoblast implantation. Intramuscular implantation of the transduced myoblasts resulted in a gene transfer which was confined locally to the region of injection, with no dissemination to other organs and tissues including testis. Additionally, basic fibroblast growth factor co-injected with primary myoblasts significantly improved the expression level of recombinant factor IX in vivo. These results demonstrate that primary myoblast-mediated gene therapy for hemophilia B is feasible and safe, and can be optimized by using cytokines or other conditions which augment myoblast survival and fusion with myofibers.

Biology of factor IX.

Within the past 20 years or so, factor IX has been at the centre of particularly intensive studies of its physiology, pathology and biochemistry as well as its molecular genetics and biology. With the complete nucleotide sequence of its human gene determined in 1985 and the molecular defects of over 600 abnormal human factor IX genes analysed to date, factor IX is among the few mammalian proteins which have been exhaustively studied in almost every aspect. The enormous amount of information we now have on this medium-sized plasma protein sheds light on how a gene and its protein evolve, how the protein carries out a highly regulated, specific and pivotal role in the delicately balanced blood coagulation reaction, and the correlation between clinical presentations and its highly diverse molecular mechanism of defects. This wealth of knowledge makes factor IX an excellent model for deeper study, such as truly quantitative analysis of its structure-function relationship and in vivo function and regulation. It will also provide a sound foundation which may lead to improved treatment of haemophilia B and perhaps to its cure. This paper attempts to review the recent progress in research on factor IX.

Implanted myoblasts not only fuse with myofibers but also survive as muscle precursor cells.

Intramuscular implanted myoblasts can fuse with existing myofibers. Here we report that implanted primary myoblasts marked with retroviral transgenes can also persist as muscle precursor cells. These cells can be recovered as viable myoblasts from muscles of recipient mice even months after myoblast implantation, and they can fully resume expression of the transgenes in culture. Upon re-implantation into muscles, they again not only fuse with existing myofibers, but also survive as muscle precursor cells in the tissue. These reserve myogenic cells should be able to contribute to host myofibers in muscle regeneration when the recombinant myofibers are damaged, providing an additional mechanism to maintain a persistent expression of transgenes delivered by myoblast-mediated gene transfer.