Association Between Psychotic and Dissociative Symptoms: Further Investigation Using Network Analysis

The association and overlap between psychotic and dissociative phenomena have been increasingly recognized. Previous studies found that psychotic symptoms are closely associated with post-traumatic and dissociative symptoms and that these trauma-related phenomena may mediate the relationship between trauma and psychotic symptoms. It remained less explored which specific post-traumatic and dissociative symptom clusters are particularly associated with psychotic symptoms. This cross-sectional study used a data-driven approach (network analysis) to explore the associations among different psychotic and post-traumatic/dissociative symptom clusters in an online convenience predominantly female sample (N = 468)(59.2% had ever seen a psychiatrist). Participants completed well-established multidimensional measures that assessed different symptom clusters of psychosis, dissociation, and PTSD. In addition, multiple mediation analysis was conducted to examine which post-traumatic/dissociative symptoms could mediate the relationship between childhood and adulthood trauma and different psychotic symptoms. Our results confirmed previous findings that PTSD and dissociative symptoms are closely associated with psychotic symptoms. More importantly, both data-driven and multiple mediation analysis results indicated that identity dissociation was particularly associated with perceptual anomalies and bizarre experiences, while emotional constriction was particularly associated with negative symptoms. It is important to screen for trauma and dissociation and provide trauma-and dissociation-informed care when working with people at risk of or experiencing psychosis. Further longitudinal studies using more representative samples are needed.

A Preliminary Longitudinal Analysis of Symptom Management, Post-traumatic Stress, and Depressive Symptoms in Chinese Adults with Dissociative Symptoms

People with dissociative symptoms are generally poly-symptomatic and require high levels of healthcare resources. Post-traumatic stress disorder (PTSD) and depressive symptoms are two major disabling comorbid symptoms in people with dissociative symptoms. While the sense of control over symptoms may be associated with PTSD and dissociative symptoms, the interplay among these factors over time remains unexplored. This study examined the predictors of PTSD and depressive symptoms in people with dissociative symptoms. Longitudinal data from 61 participants with dissociative symptoms were analyzed. Participants completed self-report measures of dissociative, depressive, and PTSD symptoms and the sense of control over symptoms two times (T1 & T2) with an interval of over one month. PTSD and depressive symptoms were not transient or time-specific, but they persisted over time in our sample. Hierarchical multiple regression analyses revealed that, after controlling for age, treatment usage and baseline symptom severity, T1 symptom management scores (β = -.264, p = .006) negatively predicted T2 PTSD symptoms, while T1 PTSD symptoms (β = .268, p = .017) positively predicted T2 depressive symptoms. T1 depressive symptoms (β = -.087, p = .339) did not predict T2 PTSD symptoms. The findings highlight the importance of improving symptom management skills and treating comorbid PTSD symptoms when working with people with dissociative symptoms.

Substance abuse among mothers in Taiwan: Investigating its prevalence and testing the trauma model

Substance abuse is a serious problem in our society. In particular, household or parental substance abuse could lead to adverse childhood experiences for the affected children. However, little is known about the prevalence of substance abuse among parents, especially in Asian societies. Moreover, although the trauma model of addiction has significant implications for the prevention and treatment of substance abuse, most evidence comes from Western samples. To address these knowledge gaps, we examined the prevalence of substance abuse in a sample of mothers in Taiwan and tested the trauma model of substance abuse. A total of 867 Taiwanese mothers completed standardized self-report assessments in 2023. The screening results indicated that the 12-month prevalence of drug abuse and alcohol abuse was 12.3% and 7.3%, respectively; 15.5% had either or both drug and alcohol abuse. Most types of trauma exposure were associated with drug abuse severity, while interpersonal stress and dissociative symptoms were associated with alcohol abuse severity, even after controlling for a variety of demographic and health variables as well as general psychopathology (i.e., depressive symptoms). The relatively high prevalence of substance abuse among Taiwanese mothers in our sample is concerning, particularly when compared to the rates reported in other Asian samples. We also provide preliminary cross-cultural evidence supporting the self-medication theory and the trauma model of substance abuse in the Asian context. We discuss the potential importance of addressing trauma and stress to prevent substance abuse and call for follow-up studies.

Is teacher violence a form of betrayal trauma? Relationship with mental health problems among young adults

BACKGROUND

Childhood trauma is one of the most preventable risk factors for mental health problems. Considering the substantial amount of time that young people spend in school during their early years, it is important to understand the potential impacts of teachers' behaviors on students' mental health.

OBJECTIVES

This study examined the relationship between exposure to teacher violence and mental health problems.

PARTICIPANTS AND SETTING

An international sample of young adults aged 18 to 24 (N = 283).

METHODS

Participants completed self-report measures of childhood trauma, exposure to teacher violence, depressive symptoms, post-traumatic stress, and alcohol misuse.

RESULTS

Exposure to teacher violence could be reliably and validly measured using the Teacher Violence Scale (TVS). Current mental health problems - including depressive symptoms, post-traumatic stress, and alcohol misuse - were associated with exposure to teacher violence during high school years, but not with childhood non-betrayal trauma.

CONCLUSIONS

Our findings expand the application of the betrayal trauma theory to school settings and point to the importance of preventing and managing teacher violence. It is important to provide more support and training to teachers and enhance monitoring measures in schools. More research on the prevalence and correlates of exposure to teacher violence is needed. We also provided first evidence supporting the reliability and validity of the English version of the TVS to facilitate future research.

Dissociative symptoms among community health service users in Hong Kong: a longitudinal study of clinical course and consequences

Background: Previous studies have demonstrated the high prevalence of dissociative symptoms and their association with considerable healthcare costs. However, there is a lack of studies that describe whether dissociative symptoms persist and lead to other clinical outcomes over time in the community.Objectives: This study investigated the persistence, predictors, and consequences of dissociative symptoms in the community.Methods: We analyzed longitudinal data in a sample of community health service users in Hong Kong (N = 173).Results: A relatively high proportion (63.6%) of participants with baseline dissociative symptoms continued to exhibit dissociative symptoms after approximately 9 months. Baseline non-betrayal trauma predicted subsequent dissociative symptoms (β = .141, p = .024). Participants with baseline dissociative symptoms were more likely to have received subsequent emergency mental health services (9.1% vs 0.7%, p = .005). Baseline dissociative symptoms significantly predicted subsequent post-traumatic symptoms (β = .165 to .191, p < .05) and difficulty in social and occupational participation (β = -.152 to -.182, p < .05) even after controlling for baseline scores, trauma exposure, and use of professional support. The predictive role of dissociative symptoms on subsequent disturbances in self-organization symptoms and social participation difficulty remained significant after applying the Bonferroni correction.Conclusions: This is one of the very few studies showing that dissociative symptoms are persistent to a certain degree and could predict other symptoms and subsequent impairments even in community settings. Factors that affect the trajectory of dissociative symptoms should be further investigated. Regular screening for dissociative symptoms is recommended. Considering its prevalence, persistence, and clinical and social consequences, dissociation should be given greater public health attention.

Persistence and clinical consequences of post-traumatic and dissociative symptoms in people with depressive symptoms: a one-year follow-up study

BACKGROUND

Recent studies found that post-traumatic and dissociative symptoms are common in people with depressive symptoms. Although a trauma-related subtype of depression has been proposed, little is known about the persistence and clinical consequences of these symptoms.

OBJECTIVE

This one-year follow-up study investigated the persistence and clinical consequences of post-traumatic and dissociative symptoms in people with depressive symptoms.

METHODS

We analyzed longitudinal data from an international sample of people self-reporting depressive emotions (N = 152) (mean Patient Health Questionnaire-9 score = 17.27; SD = 6.31).

RESULTS

More than half (58.4%) of participants with baseline post-traumatic stress disorder (PTSD) still met the criteria for PTSD after one year. Participants with dissociative symptoms at baseline were significantly more likely to report lifetime psychiatric hospitalization (31.2% vs 14.7%), past-year use of psychiatric hospitalization (10.4% vs 0%) and emergency services (16.9% vs 4%) than those without dissociative symptoms. All post-traumatic and dissociative symptom clusters were cross-sectionally (r = .286 to .528, p < .001) and longitudinally (r = .181 to .462, p < .001) correlated with depressive symptoms. A sense of current threat (β = .146, p < .05) and negative self-concept (β = .173, p < .05) at baseline significantly predicted depressive symptoms after one year.

CONCLUSIONS

These findings contribute to the increasing body of knowledge regarding the PTSD/dissociation-depression comorbidity. Given their persistence and clinical consequences, we recommend that post-traumatic and dissociative symptoms be regularly screened for in clinical settings. The existence of a possible trauma-related subtype of depression should receive more attention in both research and clinical practice.

Borderline personality disorder features and their relationship with trauma and dissociation in a sample of community health service users

BACKGROUND

Previous studies have indicated that borderline personality disorder (BPD) is closely associated with trauma and dissociation. Nevertheless, BPD is a heterogeneous condition, and not all people with BPD have severe dissociation. This study examined whether the relationship of BPD features with trauma and dissociation would remain significant after controlling for some general non-specific mental health distress. We also made the first attempt to explore which specific BPD features would be particularly associated with dissociation.

METHODS

We analyzed survey data from a sample of community health service users in Hong Kong (N = 376). Hierarchical multiple regression and data-driven network analysis were used.

RESULTS

The lifetime prevalence of DSM-5 BPD was 16.0% in our sample. Of participants who met criteria for BPD, 43.3% scored above cutoff on the dissociation measures, thus possibly having clinically significant dissociative symptoms. BPD features were associated with adulthood trauma and psychoform dissociation even after controlling for age, depression and self-esteem. Network analysis showed that some BPD features - including impulsivity, identity disturbance and suicidal/self-mutilation behaviors - were particularly associated with dissociation; other BPD features such as interpersonal-related problems had relatively weak to no connection with dissociation.

CONCLUSIONS

Our results suggested that some particular BPD features might be dissociative in nature, although further longitudinal research is required. We argue that a trauma-informed perspective should be employed when working with clients presenting with BPD features despite these features being commonly stigmatized. Further research on the intervention needs of the people with BPD who suffer from high levels of dissociation is required.

Community social work in Hong Kong during COVID-19: Intervention strategies to address social injustices

In Hong Kong, professional social workers made their presence felt when they delivered a variety of services at the height of the pandemic. Social workers who were working in community development projects or who had adopted community work approaches have become the major service providers when the availability and accessibility of other types of social services have been seriously impeded. This article reports on a qualitative research study conducted to examine (1) how community social workers have planned and implemented services, (2) their use of information and communication technologies (ICTs), and (3) ideas for addressing injustices in disaster management work.

Prevalence and sociocultural correlates of post-traumatic stress disorder and complex PTSD among Chinese community health service users in Hong Kong

OBJECTIVES

Complex post-traumatic stress disorder (CPTSD) is a newly recognized trauma disorder in ICD-11. Little is known about the prevalence and correlates of CPTSD in primary care settings. Its cultural aspects also remained minimally explored. This study investigated the prevalence and sociocultural correlates of PTSD and complex PTSD among Chinese community health service users in Hong Kong.

METHODS

This study investigated ICD-11 PTSD and CPTSD in a sample of adults (N = 376) who had recently received services from Registered Chinese Medicine Practitioners in Hong Kong. Traditional Chinese medicine service is part of primary care services in Chinese societies. Participants completed self-report measures of CPTSD, trauma exposure, perceived family support, perceived caregiver's Chinese traditionality/modernity, participation (social activities and occupational productivity), depression and pain.

RESULTS

The past-month prevalence of ICD-11 PTSD and CPTSD was 5.6% and 18.4%, respectively, in our sample. Chi-square tests and one-way ANOVAs revealed that participants with CPTSD were younger and reported more trauma, lower family support, lower levels of social participation and productivity, more depressive symptoms and pain, and more social welfare and mental health service usages than those without PTSD. We found that perceived caregiver's Chinese modernity (e.g. egalitarianism) was negatively correlated with CPTSD symptoms. Apart from age, non-betrayal trauma had the strongest association with classical PTSD symptoms, while betrayal trauma and perceived family support had the strongest association with disturbances in self-organization symptoms.

CONCLUSION

This study provides the first data regarding the prevalence and correlates of ICD-11 PTSD and CPTSD among community health service users in Hong Kong. PTSD and CPTSD are common but often unrecognized mental health problems which are associated with more impairments and more service needs.

Interpersonal stress mediates the relationship between childhood trauma and depressive symptoms: Findings from two culturally different samples

OBJECTIVE

Childhood trauma is associated with adulthood depressive symptoms, but very few studies explored potential social and interpersonal mediators behind this association. This study made the first attempt to test the potential mediating effects of interpersonal stress in the associations between childhood betrayal and non-betrayal trauma and depressive symptoms.

METHOD

We analyzed data in a sample of English-speaking adults from diverse backgrounds (from 19 different countries, mainly from Western countries) (N = 468). We then replicated and compared the results with those in another convenience sample of Chinese-speaking younger adults with different cultural backgrounds and mental health status (N = 205).

RESULTS

The results in both samples indicated that (1) childhood betrayal trauma had a stronger relationship with depressive symptoms than childhood non-betrayal trauma and that (2) interpersonal stress was a significant mediator in the relationship between childhood betrayal trauma and depressive symptoms, even when childhood non-betrayal trauma was included as a covariate. The indirect effect of childhood non-betrayal trauma on depressive symptoms through interpersonal stress was not consistent in two samples.

CONCLUSIONS

Our findings point to the importance of taking social and interpersonal contexts into account when investigating, preventing and managing depression in trauma-exposed populations. Early social interventions such as family interventions, interpersonal skills training and building social resources may have the potential to change the trajectory of the development of mental health problems in trauma survivors.

Access to safe and legal abortion for teenage women from deprived backgrounds in Hong Kong

This paper reports on a qualitative study in 2007-08 on the abortion experiences of teenage women from deprived backgrounds in Hong Kong. Twenty-nine young women aged 13-24 who had undergone one or more induced abortions in their teen years were interviewed and participated in group empowerment sessions. Ten were unemployed, four were students, the rest were employed on low pay in unskilled occupations. Abortion services are legal and available in public and private services, but they charge fees ranging from HK$310 to $10,000, and do abortions only up to 24 weeks of pregnancy. Many young women resort to poor quality illegal clinics and clinics in mainland China because the cost is lower, they do not wish to tell their parents, who would be asked for consent, and/or they want to protect their sex partners, who may be reported and prosecuted if the girl is under-age. There is a need to strengthen services for teenage women in Hong Kong, especially those who are pregnant and from deprived backgrounds. There is also a need for professionals who deliver adolescent health and social welfare services, and for society to rethink and re-examine its views and attitudes towards teenage pregnancy, sexuality and abortion.

Association between betel quid chewing, periodontal status and periodontal pathogens

The present investigation examined whether an association exists between betel quid chewing and signs of periodontal disease and determined the prevalence of Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis by polymerase chain reaction. The periodontal status of 34 betel quid chewers and 32 non-betel quid chewers were compared. A significantly higher prevalence of bleeding on probing was found in betel quid chewers than non-chewers among the subjects with higher plaque level, greater gingival inflammation, deeper probing depth or greater attachment loss. Also, the results suggested that betel quid chewers may harbor higher levels of infection with A. actinomycetemcomitans and P. gingivalis than non-betel quid chewers. The association persists after adjusting for severity of the clinical parameters. In conclusion, betel quid chewing was associated with a higher prevalence of bleeding on probing where higher clinical levels of disease existed, and with a likelihood of subgingival infection with A. actinomycetemcomitans and P. gingivalis.

Effects of areca nut extracts on the functions of human neutrophils in vitro

Aqueous extracts of ripe areca nut without husk (ripe ANE) and fresh and tender areca nut with husk (tender ANE) were examined for their effects on the defensive functions of human neutrophils. Exposure of peripheral blood neutrophils to ripe ANE and tender ANE inhibited their bactericidal activity against oral pathogens, including Actinobacillus actinomycetemcomitans and Streptococcus mutans, in a dose-dependent manner. At the concentrations tested, ripe and tender ANEs did not significantly affect the viability of neutrophils as verified by their ability to exclude trypan blue dye. However, both ANEs inhibited the production of bactericidal superoxide anion by neutrophils as measured by cytochrome c reduction. Moreover, the ripe ANE inhibited neutrophils more effectively than did tender ANE. Arecoline, a major alkaloid of areca nut, only exhibited an inhibitory effect on the functions of neutrophils when high concentrations were used. Therefore, arecoline could not be used to explain the inhibitory effects observed for ANEs. In conclusion, our results demonstrated that ripe and tender ANEs reduced the antibacterial activity and the superoxide anion production of neutrophils. This effect may contribute to a less efficient elimination of bacteria from the periodontal environment. Inhibition of the antimicrobial functions of neutrophils may alter the microbial ecology of the oral cavity, and this may be one possible mechanism by which areca nut compromises the oral health of users of areca nut products.

Recurrent lacrimal sac papilloma: case report

Tumors of the lacrimal sac are rare. Benign papillomas comprise approximately 40% of all neoplasms of the lacrimal drainage system. They often present insidiously with symptoms of dacryostenosis or dacryocystitis. Recurrent bouts of dacryocystitis and nasolacrimal duct obstruction were reported in a 35-year-old man over a period of 13 years. A medial canthal mass was noted in the 6th year after the onset of symptoms. A tumor was discovered incidentally during surgical intervention for presumed dacryostenosis. Surgical removal of the tumor and dacryocystorhinostomy were performed. The histopathologic report turned out to be benign papiloma. Local recurrences occurred during the follow-up period. In addition to surgical excision, we applied cryotherapy and CO2 laser to prevent further recurrence. This case we presented the characteristic recurrence of lacrimal sac papilloma and implied the possibility of tumor occurrence in a patient with recurrent dacryocystitis. We must bear in mind that a recurrent dacryocystitis may be a presentation of a lacrimal sac tumor, because early diagnosis and aggressive treatment can prevent recurrence and result in a cure.

Analysis of the steps involved in Dengue virus entry into host cells

The initial steps of dengue viral entry have been divided into adsorption and penetration using acid glycine treatment to inactivate extracellular virus after attachment to baby hamster kidney (BHK) cells but prior to penetration. First, we showed that virus infection was accomplished within 2 h after adsorption. Second, the assay was used to examine the properties of dengue envelope E protein-specific monoclonal antibodies (MAbs), lectins, and heparin. We found that three MAbs, 17-2, 46-9, and 51-3, may neutralize dengue 2 virus (DEN-2) through inhibition of not only viral attachment but also of penetration. However, one MAb, 56-3.1, interfered specifically with attachment. Therefore, the functional domains of E protein involved in attachment and penetration may be different. Moreover, studies with lectins indicated that carbohydrates, especially alpha-mannose residues, present on the virion glycoproteins may contribute to binding and penetration of the virus into BHK and mosquito C6/36 cells. Finally, virus infectivity was inhibited by heparin through its blocking effects at both virus attachment and penetration. This suggests that cell surface heparan sulfate functions in both viral attachment and penetration of DEN-2 virus. In conclusion, our results further elucidated some aspects of the dengue virus entry process.

Sequences regulating poly(A) site selection within the adenovirus major late transcription unit influence the interaction of constitutive processing factors with the pre-mRNA

The adenovirus major late transcription unit (MLTU) encodes five families of mRNAs, L1 to L5, each distinguished by a unique poly(A) site. Use of the promoter-proximal L1 poly(A) site predominates during early infection, whereas poly(A) site choice shifts to the promoter-distal sites during late infection. A mini-MLTU containing only the L1 and L3 poly(A) sites has been shown to reproduce this processing switch. In vivo analysis has revealed that sequences extending 5' and 3' of the L1 core poly(A) site are required for efficient processing as well as for regulated expression. By replacement of the L1 core poly(A) site with that of the ground squirrel hepatitis virus poly(A) site, we now demonstrate that the L1 flanking sequences can enhance the processing of a heterologous poly(A). Upon recombination of the chimeric L1-ground squirrel hepatitis virus poly(A) site onto the viral chromosome, the L1 flanking sequences were also found to be sufficient to reproduce the processing switch during the course of viral infection. Subsequent in vitro analysis has shown that the L1 flanking sequences function to enhance the stability of binding of cleavage and polyadenylation specificity factor to the core poly(A) site. The impact of L1 flanking sequences on the binding of cleavage and polyadenylation specificity factor suggests that the regulation of the MLTU poly(A) site selection is mediated by the interaction of constitutive processing factors.

The interaction of glycoprotein C of herpes simplex virus types 1 and 2 with the alternative complement pathway

Glycoprotein C (gC) of herpes simplex virus type 1 (HSV-1) or type 2 (HSV-2) binds the human complement fragment C3b, but the two proteins differ in their ability to bind C3b on infected cell surfaces. In addition, gC-1, but not gC-2, accelerates the decay of the alternative pathway C3 convertase, thereby affecting later steps of the complement cascade. Previously, we constructed linker insertion and deletion mutants of gC-1 and gC-2 and used transient transfection to express mutant proteins in uninfected cells. In spite of the differences between gC-1 and gC-2, C3b binding was localized to residues within the central portion of both proteins, encompassing the first four cysteines. For gC-1, deletion mutants lacking amino acids 33 to 123 or 367 to 469 or lacking both regions still bound C3b. We recombined these deleted forms of gC-1 into gC-39, an HSV-1 strain lacking the gC gene. The altered forms of gC-1 were incorporated into virions, expressed on the surface of infected cells, and bound C3b. We used these proteins to investigate the structural basis for the inhibitory action of gC-1 on the complement cascade. We found that gC-1 does not inhibit formation of the alternative pathway C3 convertase. This convertase is stabilized by the serum protein properdin. Purified gC-1, but not gC-2, inhibits the binding of properdin to C3b, suggesting that this destabilizes the convertase. The mutant lacking amino acids 367 to 449 was able to inhibit properdin binding to a limited extent when present at high concentrations, although it bound to C3b more weakly than wild-type gC. In contrast, the protein lacking amino acids 33 to 123 was unable to inhibit properdin binding to C3b. Thus, gC-1 contains two structural domains, one for C3b binding, residues 124 to 366, and another, residues 33 to 133, which interferes with properdin binding to C3b.

Limited joint mobility of the hand: prevalence and relation to chronic complications in non-insulin-dependent diabetes mellitus patients

A total of 170 non-insulin-dependent diabetes mellitus (NIDDM) patients admitted to Kaohsiung Chang Gung Memorial Hospital during the period from January 1988 to December 1989 were examined for the presence of cheiroarthropathy. Fifty-four percent (92 patients) had limited joint mobility (LJM) of the hand, a prevalence significantly higher than that of non-diabetic controls (7%). Duration of diabetes was positively related to the severity of LJM (p = 0.03, chi-square contingency table). Chronic diabetic complications such as cataracts (p = 0.04) and overt proteinuria (p = 0.03) were also associated with the presence of LJM, and diabetic retinopathy (p = 0.007); vision-threatening retinopathy was strongly associated with the presence of LJM (p = 0.0002). The sex ratio, HbA1c and creatinine clearance rates did not show significant differences between patients with and without LJM. In conclusion, the occurrence of LJM of the hand in NIDDM patients observed at this hospital is common and is often accompanied by other chronic diabetic complications. Its presence should alert physicians to other associated diabetic complications with increased morbidity and mortality.

Structural basis of C3b binding by glycoprotein C of herpes simplex virus

Glycoproteins C (gC) from herpes simplex virus type 1 (HSV-1) and HSV-2, gC-1 and gC-2, bind the human complement fragment C3b, although the two glycoproteins differ in their abilities to act as C3b receptors on infected cells and in their effects on the alternative complement pathway. Previously, we identified three regions of gC-2 (I, II, and III) which are important for C3b binding. In this study, our goal was to identify C3b-binding sites on gC-1 and to continue our analysis of gC-2. We constructed a large panel of mutants by using the cloned gC-1 and gC-2 genes. Most of the mutant proteins were transported to the surface of transiently transfected L cells and reacted with one or more monoclonal antibodies to discontinuous epitopes. By using 31 linker insertion mutants spread across the coding region of gC-1, we identified four regions in the ectodomain of gC-1 which are important for C3b binding, three of which are similar in position to C3b-binding regions I, II, and III of gC-2. Region III shares some similarities with the short consensus repeat found in CR1, the human complement receptor. These were, in part, the targets for construction of 20 single amino acid changes in region III of gC-1 and gC-2. These mutants identified similarities and differences in the C3b-binding properties of gC-1 and gC-2 and suggest that the amino half of region III is more important for C3b binding. However, our results do not support the concept of a structural relationship between the short consensus repeat of CR1 and gC, since mutations of some of the conserved residues, including three of four cysteines in region III, had no effect on C3b binding. Finally, we constructed four deletion mutants of gC-1, including one which lacked residues 33 to 123, as well as residues 367 to 449. This severely truncated molecule, lacking four cysteines and five potential N-linked glycosylation sites, was transported to the cell surface and retained its ability to bind monoclonal antibodies as well as C3b. Thus, the four distinct C3b-binding regions of gC-1 and several epitopes within two different antigenic sites are localized within residues 124 to 366.

The 9-kDa hydrophobic protein encoded at the 3' end of the porcine transmissible gastroenteritis coronavirus genome is membrane-associated

The open reading frame potentially encoding a 78 amino acid, 9101 Da hydrophobic protein (HP) and, mapping at the 3' end of the porcine transmissible gastroenteritis coronavirus (TGEV) genome, was shown to be expressed during virus replication. The cloned HP gene was placed in a plasmid under control of the T7 RNA polymerase promoter and in vitro translation of transcripts generated in vitro yielded a 9.1-kDa protein that was immunoprecipitable with porcine hyperimmune anti-TGEV serum. Antiserum raised in rabbits against a 31 amino acid synthetic polypeptide that represented the central hydrophilic region of HP specifically immunoprecipitated HP from TGEV-infected cells. HP was further shown to become associated with microsomal membranes during synthesis in vitro and was found to be closely associated with the endoplasmic reticulum and cell surface membranes in infected cells. The intracellular location of HP suggests that it may play a role in the membrane association of replication complexes or in virion assembly.

Coronavirus subgenomic minus-strand RNAs and the potential for mRNA replicons

The genome of the porcine transmissible gastroenteritis coronavirus is a plus-strand, polyadenylylated, infectious RNA molecule of approximately 20 kilobases. During virus replication, seven subgenomic mRNAs are generated by what is thought to be a leader-priming mechanism to form a 3'-coterminal nested set. By using radiolabeled, strand-specific, synthetic oligodeoxynucleotide probes in RNA blot hybridization analyses, we have found a minus-strand counterpart for the genome and for each subgenomic mRNA species in the cytoplasm of infected cells. Subgenomic minus strands were found to be components of double-stranded replicative forms and in numbers that surpass full-length antigenome. We propose that subgenomic mRNA replication, in addition to leader-primed transcription, is a significant mechanism of mRNA synthesis and that it functions to amplify mRNAs. It is a mechanism of amplification that has not been described for any other group of RNA viruses. Subgenomic replicons may also function in a manner similar to genomes of defective interfering viruses to lead to the establishment of persistent infections, a universal property of coronaviruses.