Posttraumatic stress disorder in older people after a fall

BACKGROUND

Posttraumatic Stress Disorder (PTSD) is a debilitating psychological condition, never studied in relation to falls in older people. This study determines the prevalence and correlates of PTSD in older people post-fall.

METHOD

A prospective survey study, with baseline data collected by interview in hospital post-fall and by postal self-completion at 12 and 24 weeks post-baseline. A convenience sample of 196 people (> or = 65 years) were serially recruited, 87.9% of those eligible. Information collected at baseline included falls-related data, activity problems, fear of falling, PTSD symptoms, anxiety and depression, and at follow-up PTSD symptoms, anxiety and depression, the receipt of rehabilitation and further falls.

RESULTS

In hospital, of 40 participants whose fall had occurred over 1 month previously 35% had full acute PTSD and 17.5% had partial acute PTSD. At follow-up full or partial chronic PTSD was found in 26.1% of participants at first follow-up, and in 27.4% of participants at second follow-up. Older age, pre-fall activity problems, fear of falling, and anxiety assessed at baseline were associated (p < 0.05) with follow-up PTSD diagnosis, as were anxiety and depression assessed concurrently.

CONCLUSION

PTSD occurs in a substantial minority of older people post-fall. No pattern emerged of factors predictive of PTSD, although the association between fear of falling and PTSD suggests some patients thought to have fear of falling may be manifesting PTSD, and require identification to enable therapeutic intervention.

Posttraumatic stress and co-morbidity following myocardial infarction among older patients: the role of coping

This study aimed to investigate co-morbidity and coping strategies among older patients who suffer from different levels of posttraumatic stress disorder (PTSD) following myocardial infarction. Ninety-six older myocardial infarction (MI) patients were recruited from two general practices and completed the Posttraumatic Stress Diagnostic Scale (PDS), the General Health Questionnaire-28 (GHQ-28) and the COPE Scale. Ninety-two older patients with no previous MI experience constituted the control. Using the PDS, 30, 42 and 28% had full, partial and no-PTSD respectively. There were significant differences between the patient groups and the control on all GHQ-28 sub-scales. Significant differences were also identified between the patient groups in the following coping strategies: seeking emotional social support, suppression of competing activities, restraint coping, focusing on and venting of emotion, mental and behavioural disengagement. Controlling for bypass surgery, previous mental health difficulties, angioplasty, heart failure and angina, MANCOVA results did not change the overall results of the GHQ-28 but changed the results of coping in that seeking emotional social support and behavioural disengagement stopped being significant. Coping was a partial mediator between different levels of post-MI PTSD and co-morbidity. Depending on the severity of PTSD symptoms, co-morbidity and coping strategies can vary among older patients. Older patients with full-PTSD tend to use both maladaptive coping strategies as well as problem-focused coping.

Comorbidity and personality traits in patients with different levels of posttraumatic stress disorder following myocardial infarction

More research is needed to further our understanding of posttraumatic stress responses and comorbidity following myocardial infarction (MI), and to help us identify more clearly the personality traits which indicate that a person is more prone to developing post-MI posttraumatic stress disorder (PTSD). This study aimed to 1) investigate the comorbidity of patients who suffered from different levels of posttraumatic stress disorder following myocardial infarction (i.e. post-MI PTSD), and 2) investigate to what extent patients with different levels of post-MI PTSD differed in their personality traits. One hundred and twenty MI patients from two general practices were recruited for the study. They were asked to complete the Posttraumatic Stress Diagnostic Scale (PDS), the General Health Questionnaire-28 (GHQ-28) and the NEO-Five Factor Inventory (NEO-FFI). They were divided into a no-PTSD group, a partial-PTSD group and a full-PTSD group, according to the scores of the PDS. One hundred and sixteen members of the general public were also recruited for comparison purposes. They were asked to complete the GHQ-28. The results showed that patients with full-PTSD reported significantly more somatic problems, anxiety, social dysfunction and depression than the other two patient groups and the control group. When age, bypass surgery, mental health problems before MI and angioplasty were controlled for, patients with full-PTSD also reported greater symptom severity of the four GHQ subscales than the other two patient groups. Patients with full-PTSD were significantly more neurotic than those with no-PTSD and partial-PTSD. Patients with full-PTSD were less agreeable than patients with no-PTSD. Regression analyses showed that personality did not moderate the relationship between PTSD and comorbidity. To conclude, following MI, those with full-PTSD tend to report more severe comorbidity than those who have not developed PTSD fully. The former can also be distinguished from the latter by virtue of their specific personality traits.

Locus of control among spinal cord injury patients with different levels of posttraumatic stress disorder

Two hypotheses were investigated in the present study: 1) Patients with full posttraumatic stress symptoms following spinal cord injury (SCI) would experience more general health problems than those with partial posttraumatic stress disorder (PTSD), with no-PTSD and the control group; 2) Patients with full PTSD would endorse the external locus of control more than those with partial PTSD, no-PTSD and the control group. Sixty-two patients were recruited from a specialized rehabilitation clinic for spinal cord injury. The control group comprised 60 participants without SCI. Patients with SCI were assessed using the Posttraumatic Stress Disorder Checklist, the General Health Questionnaire-28 (GHQ-28) and the Multidimensional Health Locus of Control (MHLC). The control group was assessed using the GHQ-28 and the MHLC. The full PTSD group experienced more somatic problems, anxiety, social dysfunction and depression than the partial PTSD, the no-PTSD and the control groups. The results also showed that the full PTSD group endorsed significantly more external health locus of control than the control group. However, no significant differences were found between the three patient groups in health locus of control. The three PTSD sub-scales were positively correlated with general health problems. Further analyses showed that partial PTSD patients with paraplegia and partial PTSD patients whose SCI had a medically related cause were more likely to report less internal locus of control than other patients. Patients who suffered from full PTSD experienced more general health problems than those with fewer PTSD symptoms and those without SCI. External locus of control was a distinctive strategy that SCI-PTSD patients used in coping with the effects of SCI-PTSD.

Rapid test for the evaluation of the activity of the prodrug hydroxymethylnitrofurazone in the processing of Trypanosoma cruzi messenger RNAs

No fully effective treatment has been developed since the discovery of Chagas' disease by Carlos Chagas in 1909. Since drug-resistant Trypanosoma cruzi strains are occurring and the current therapy is effectiveness in the acute phase but with various adverse side effects, more studies are needed to characterize the susceptibility of T. cruzi to new drugs. Many natural and/or synthetic substances showing trypanocidal activity have been used, even though they are not likely to be turned into clinically approved drugs. Originally, drug screening was performed using natural products, with only limited knowledge of the molecular mechanism involved in the development of diseases. Trans-splicing, which is unusual RNA processing reaction and occurs in nematodes and trypanosomes, implies the processing of polycistronic transcription units into individual mRNAs; a short transcript spliced leader (SL RNA) is trans-spliced to the acceptor pre-mRNA, giving origin to the mature mRNA. In the present study, permeable cells of T. cruzi epimastigote forms (Y, BOL and NCS strains) were treated to evaluate the interference of two drugs (hydroxymethylnitrofurazone - NFOH-121 and nitrofurazone) in the trans-splicing reaction using silver-stained PAGE analysis. Both drugs induced a significant reduction in RNA processing at concentrations from 5 to 12.5 microM. These data agreed with the biological findings, since the number of parasites decreased, especially with NFOH-121. This proposed methodology allows a rapid and cost-effective screening strategy for detecting drug interference in the trans-splicing mechanism of T. cruzi.

Posttraumatic stress disorder and general health problems following myocardial infarction (Post-MI PTSD) among older patients: the role of personality

OBJECTIVES

This study aimed to: (1) investigate the degree to which older MI patients experienced post-MI PTSD and general health problems, and to (2) identify the association between five personality traits, post-MI PTSD and general health problems among these older people.

METHODS

The sample comprised 96 older MI patients and were recruited from two general practices. They were interviewed using the Posttraumatic Stress Diagnostic Scale (PDS), the General Health Questionnaire-28 (GHQ-28) and the NEO-Five Factor Inventory (NEO-FFI). The control group comprised 92 older people who experienced no MI. They were assessed using the GHQ-28.

RESULTS

The older MI patients experienced hyperarousal the most, followed by avoidance and re-experiencing symptoms. PDS revealed that 30% had full PTSD. The older patients were conscientious and agreeable individuals. They were also somewhat extraverted and open to experience. They also showed traits of neuroticism. Controlling for bypass surgery, heart failure, previous mental health difficulties, angina and angioplasty, regression analyses showed that neuroticism predicted re-experiencing and avoidance symptoms and general health total. Neuroticism and less agreeableness predicted hyperarousal symptoms.

CONCLUSIONS

MI older patients could manifest PTSD symptoms and general health problems following their MI. Personality traits, particularly neuroticism and antagonism, played a role in the manifestation of these symptoms.

The relationship between posttraumatic stress disorder following spinal cord injury and locus of control

OBJECTIVE

This study examined whether locus of control was associated with spinal cord injury posttraumatic stress disorder (SCI-PTSD).

METHODS

Sixty-two SCI patients and 54 people without SCI participated in the study. The patients were assessed using the Posttraumatic Stress Disorder Checklist (PCL), the General Health Questionnaire-28 (GHQ-28) and the Multidimensional Health Locus of Control (MHLC). The control group was assessed using the GHQ-28 and the MHLC.

RESULTS

Forty-four percent of patients suffered from full-blown PTSD. SCI patients experienced significantly more general health problems than the control. Type of SCI and trauma recency were not significantly correlated with PTSD symptoms or general health problems but previous traumatic events were. Regression analyses showed that internal health locus of control (IHLC) and powerful other locus of control (POLC) predicted the re-experiencing symptom; IHLC predicted the avoidance symptom; POLC predicted GHQ-28 total.

CONCLUSION

SCI patients' perceptions of whether their health was or was not determined by their own behaviour (i.e. internal or external locus of control) were associated with SCI-PTSD.

Spinal cord injury, posttraumatic stress, and locus of control among the elderly: a comparison with young and middle-aged patients

This study aimed to investigate the extent to which spinal cord injury posttraumatic stress (SCI PTSD) responses and the use of the external or internal health locus of control might vary according to age. Sixty-two patients with SCI were recruited for the study and divided into young (n = 23), middle-aged (n = 25) and elderly (n = 14) groups. They were assessed using the Posttraumatic Stress Disorder Checklist (PCL), the General Health Questionnaire-28 (GHQ-28), and the Multidimensional Health Locus of Control (MHLC). The results showed no significant differences between the three age groups in terms of PTSD symptoms. The elderly patients were significantly more socially dysfunctional than the other patients. The young patients believed in chance locus of control (CHLC) significantly more than the middle-aged and elderly patients. Correlation results revealed no significant relationship between PTSD symptoms and type of locus of control for the middle-aged patients. Otherwise, for both the young and elderly patients, internal health locus of control (IHLC) was negatively correlated with the avoidance symptom. For the elderly patients, powerful other locus of control (POLC) was positively correlated with the avoidance symptom. Both young and middle-aged patients revealed significant positive correlations between POLC, CHLC, and general health problems. For the elderly patients, POLC was positively correlated with social dysfunction and depression. SCI-PTSD responses did not differ according to age; however, the use of health locus of control differed depending on whether patients were younger or older.

Psychosocial benefits of solitary reminiscence writing: an exploratory study

Claims have been made that reminiscence has benefits for older people's psychological well-being, and that writing memories may be a therapeutic process. This paper describes an exploratory study in which five nursing home residents engaged in a process of writing their memories by themselves, in a series of booklets containing memory prompts and photographs, over a period of four weeks. Each completed booklet was typed up by researchers and returned to participants the following week, with a bound copy provided to participants at the end of the study period. Analysis focuses on two sets of data: an in-depth case study of one participant, and a thematic analysis of field notes, researcher reflections, and the written material produced by the other study participants. The case study revealed three main themes: views on the past; sharing the past; and confidence in writing about the past. The field note analysis indicated the presence of four themes: proof and maintenance of skills; psychological or internal processes; social contact; and pleasure in reminiscence. The writing was seen as cathartic and provided a meaningful purpose, an opportunity to exercise writing skills and memory, and a focus for participants to share key stories with others. This exploratory study suggests that there is potential in using solitary writing within a reminiscence framework to improve psychological well-being in older people. However, caution should be exercised when encouraging older people to write their stories. Issues of confidentiality, audience, support, and appropriateness of the activity for the individual need consideration.

A multiple-indicator multiple-cause model for posttraumatic stress reactions: personality, coping, and maladjustment

OBJECTIVE

This study aimed to develop a multiple-indicator multiple-cause model (MIMIC) to describe the relationship among posttraumatic stress (PTSD) responses, general health problems, death anxiety, personality factors, and coping strategies among community residents exposed to the technological disasters of aircraft and train crashes.

MATERIALS AND METHODS

One hundred forty-eight community residents, after exposure to the aircraft or train crash, were assessed using the Impact of Event Scale, the General Health Questionnaire-28, the Death Anxiety Scale, the Eysenck Personality Questionnaire, and the Ways of Coping Checklist. The control group (n = 90) comprised members of the general public, who had not been exposed to the disasters, from another city.

RESULTS

The model showed significant associations between the impact of the disaster and general health problems, which varied depending on where community residents lived in relation to the disaster site, whether they were present when the disaster occurred, and the type of disaster. The model also suggested that death anxiety was associated with type of disaster and neuroticism. The model supported the interactive model in that personality factors interacted with coping strategies in maintaining or generating PTSD and general health problems.

CONCLUSIONS

After exposure to technological disasters, community residents could develop PTSD and general health problems; however, increased death anxiety was a separate psychological reaction. The interaction between certain personality traits and coping strategies was one reason for PTSD and general health problems.

Differentiating posttraumatic stress between elderly and younger residents

This study aimed to differentiate between the posttraumatic stress responses of elderly and younger community residents who had been exposed to two technological disasters (a train collision and an aircraft crash). One hundred and forty-eight community residents were assessed using the Impact of Event Scale (IES) and the General Health Questionnaire (GHQ-28). The results showed that age differences were not affected by impact of disaster (IES), suggesting that elderly and younger community residents responded to the disasters similarly. Instead, the community residents exposed to the aircraft crash experienced significantly more intrusion and avoidance than those exposed to the train collision. Also, the community residents who had experienced high exposure to the disasters had significantly more intrusive thoughts and exhibited significantly more avoidance behavior than the low/medium exposure group. The results also showed no main effects in general health between the elderly and younger community residents, suggesting that their health status was similar. Instead, the community residents exposed to the aircraft crash had significantly more general health problems than the train disaster residents and the control group. Also, the community residents in either the low/medium or the high exposure group experienced more general health problems than the control group. Correlation coefficients showed that intrusion, avoidance, and the total impact of the disasters were significantly correlated with all general health subscales for both elderly and younger groups.

Coping with post-traumatic stress: young, middle-aged and elderly comparisons

OBJECTIVES

Debate persists about whether people of different ages react similarly to traumatic events, and whether elderly people are more vulnerable to such events, or better able to cope with them. The first aim of this paper was to shed light on this debate by comparing the post-traumatic responses of young, middle-aged and elderly community residents who had been exposed to technological disasters. The second aim was to differentiate between these three age groups in terms of coping strategies.

METHODS

One hundred and forty-eight community residents, who were exposed to two technological disasters, participated in the study. They were assessed using the Impact of Event Scale (IES), the General Health Questionnaire (GHQ-28) and the Ways of Coping Checklists (WOC).

RESULTS

The results showed that in terms of IES, GHQ and WOC scores, no significant differences were found across the three age groups. However, main effects were found according to type of disaster and intensity of exposure to disaster. One significant interaction effect was that residents exposed to the aircraft crash used significantly more confrontive coping than those exposed to the train collision, in all three age groups. Correlation coefficients results showed that for all three age groups, on the whole, the more they experienced intrusive thoughts and avoidance behaviour, the more they experienced general health problems.

CONCLUSIONS

Following exposure to technological disasters, young, middle-aged and elderly community residents could display similar post-traumatic responses and employ similar coping strategies, which contradicts the vulnerability hypothesis and the inoculation hypothesis.

Psychological sequelae: post-traumatic stress reactions and personality factors among community residents as secondary victims

The aims of the present study were twofold: first, to ascertain the severity of post-traumatic stress among community residents as secondary victims exposed to a train disaster. Secondly, we aimed to identify the association between post-traumatic stress and personality variables. Seven months after the train disaster in Stafford, United Kingdom, in 1996, 66 community residents were recruited and interviewed for the study. In the interviews, residents were assessed using the Impact of Event Scale (IES), the General Health Questionnaire (GHQ) and the Eysenck Personality Questionnaire-R Short Scale (EPQ-R). Control group data were also collected, composed of 90 community residents who lived in another city and had not been exposed to the train disaster. They were assessed using the GHQ. The results showed that 51% of the residents scored at the high IES symptom level. No significant differences were found between the community residents who lived near and further away from the crash site in terms of the IES scores. Further analyses showed that the IES scores for the present two groups of community residents were significantly lower than those of Horowitz's standardized stress clinic samples, but higher than those of Danish rescue workers involved in a train rescue operation. The GHQ results showed that 35% could be considered to be psychiatric cases. The comparisons between the GHQ scores of the present community residents with those of the control group showed that there were significant differences in somatic problems, anxiety, depression and GHQ total. With regard to personality, the community residents who lived near to the crash site were significantly more introverted but less neurotic than Eysenck's standardized samples. The community residents who lived further away were significantly more introverted but less neurotic than the standardized samples. Regression analyses revealed that neuroticism predicted intrusion, avoidance and GHQ total. The conclusion was that there can be long-term, severe post-traumatic stress effects upon community residents, as secondary victims, after exposure to a train disaster. Residents with a neurotic personality tend to be associated with post-traumatic stress reactions and general health problems.

The development and evaluation of a community attachment scheme for first-year medical students

This paper describes the development over 14 years of a Community Attachment Scheme for First Year Medical Students in Sheffield, together with feedback from tutors and students. The scheme involves pairs of students visiting families expecting a baby or experiencing an illness. The families are identified by general practitioners who act as tutors together with a behavioural scientist for groups of eight to 10 students. The scheme provides first-year students with practical experience of sociology and psychology in terms of family dynamics and illness behaviour. Assessment is part of the degree examination, and involves a written assignment on the family, together with tutors' assessments. The development of the attachment scheme took place in three phases, which are described together with feedback from tutors and students, as well as changes in methods of assessment. The basis of the Community Attachment Scheme has been self-directed problem-based learning in small groups with continuous assessment, and these principles have now extended to the rest of the medical curriculum in Sheffield, of which the Community Attachment Scheme is an integral part.

Hepatocellular carcinoma: from bedside to proteomics

Hepatocellular carcinoma (HCC or hepatoma) is the most common primary cancer of the liver. It is responsible for approximately one million deaths each year, mainly in underdeveloped and developing countries. The aetiological factors identified in the development of HCC included persistent infection by hepatitis B and hepatitis C viruses, and exposure to aflatoxins. Although immunization can protect individuals from being infected by the hepatitis B virus, the early detection of HCC in those who have been infected by the virus remains a challenge. Thus most HCCs present late and are not suitable for curative treatment. Hence there is a tremendous interest and urgency to identify novel HCC diagnostic marker(s) for early detection, and tumour specific disease associated proteins as potential therapeutic targets in the treatment of HCC. Screening for these HCC proteins has been facilitated by proteomics, a key technology in the global analysis of protein expression and understanding gene function. Present and earlier proteome analyses of HCC have used predominantly experimental in vitro systems. The protein expression profiles of several hepatoma cell lines such as HepG2, Huh7, SK-Hep1, and Hep3B have been compared with normal liver, and nontransformed cell lines (Chang and WRL-68), while a comprehensive proteome analysis to create a protein database was carried out for the cell line HCC-M. In the future, proteome analyses utilizing tumour tissues, which reflect the pathological state of HCC more closely, will be undertaken. This work will complement the gene expression studies of HCC which are already underway. Efforts have also been directed at the proteome analysis of hepatic stellate cells, as these cells play an important role in liver fibrosis. Since liver fibrosis is reversible but not cirrhosis, it is of considerable importance to identify therapeutic targets that can slow its progression.

Hepatocellular carcinoma: from bedside to proteomics

Hepatocellular carcinoma (HCC or hepatoma) is the most common primary cancer of the liver. It is responsible for approximately one million deaths each year, mainly in underdeveloped and developing countries. The aetiological factors identified in the development of HCC included persistent infection by hepatitis B and hepatitis C viruses, and exposure to aflatoxins. Although immunization can protect individuals from being infected by the hepatitis B virus, the early detection of HCC in those who have been infected by the virus remains a challenge. Thus most HCCs present late and are not suitable for curative treatment. Hence there is a tremendous interest and urgency to identify novel HCC diagnostic marker(s) for early detection, and tumour specific disease associated proteins as potential therapeutic targets in the treatment of HCC. Screening for these HCC proteins has been facilitated by proteomics, a key technology in the global analysis of protein expression and understanding gene function. Present and earlier proteome analyses of HCC have used predominantly experimental in vitro systems. The protein expression profiles of several hepatoma cell lines such as HepG2, Huh7, SK-Hep1, and Hep3B have been compared with normal liver, and nontransformed cell lines (Chang and WRL-68), while a comprehensive proteome analysis to create a protein database was carried out for the cell line HCC-M. In the future, proteome analyses utilizing tumour tissues, which reflect the pathological state of HCC more closely, will be undertaken. This work will complement the gene expression studies of HCC which are already underway. Efforts have also been directed at the proteome analysis of hepatic stellate cells, as these cells play an important role in liver fibrosis. Since liver fibrosis is reversible but not cirrhosis, it is of considerable importance to identify therapeutic targets that can slow its progression.

Hepatocellular carcinoma: from bedside to proteomics

Hepatocellular carcinoma (HCC or hepatoma) is the most common primary cancer of the liver. It is responsible for approximately one million deaths each year, mainly in underdeveloped and developing countries. The aetiological factors identified in the development of HCC included persistent infection by hepatitis B and hepatitis C viruses, and exposure to aflatoxins. Although immunization can protect individuals from being infected by the hepatitis B virus, the early detection of HCC in those who have been infected by the virus remains a challenge. Thus most HCCs present late and are not suitable for curative treatment. Hence there is a tremendous interest and urgency to identify novel HCC diagnostic marker(s) for early detection, and tumour specific disease associated proteins as potential therapeutic targets in the treatment of HCC. Screening for these HCC proteins has been facilitated by proteomics, a key technology in the global analysis of protein expression and understanding gene function. Present and earlier proteome analyses of HCC have used predominantly experimental in vitro systems. The protein expression profiles of several hepatoma cell lines such as HepG2, Huh7, SK-Hep1, and Hep3B have been compared with normal liver, and nontransformed cell lines (Chang and WRL-68), while a comprehensive proteome analysis to create a protein database was carried out for the cell line HCC-M. In the future, proteome analyses utilizing tumour tissues, which reflect the pathological state of HCC more closely, will be undertaken. This work will complement the gene expression studies of HCC which are already underway. Efforts have also been directed at the proteome analysis of hepatic stellate cells, as these cells play an important role in liver fibrosis. Since liver fibrosis is reversible but not cirrhosis, it is of considerable importance to identify therapeutic targets that can slow its progression.

Cloning and characterization of a DEAD box RNA helicase from the viable seedlings of aged mung bean

Seeds stored under adverse conditions will reduce the viability of germination as a result of induced aging. We have established a procedure to induce accelerated aging for studying the process of aging in mung bean (Vigna radiata) seeds at the molecular level. A full-length cDNA was isolated from acceleratedly aged mung bean seedlings. The cDNA, VrRH1 (Vigna radiata RNA helicase 1), contains an open reading frame of 2139 bp encoding a protein of 713 amino acids. VrRHI has seven highly conserved motifs including the DEAD box as in the case of other plant RNA helicases. VrRHI was sub-cloned into an expression vector pET-28b (+), over-expressed in Escherichia coli BL 21 and purified by a Ni2+-agarose column. The expressed protein showed double-stranded RNA unwinding and ATPase activities. Either ATP or dATP is required for the unwinding activity, indicating that VrRHI is an ATP/dATP-dependent RNA helicase. Northern blot analysis showed the presence of mRNAs hybridized with a full-length cDNA fragment of VrRHI (VrRH transcripts) in mung bean seeds that were imbibed for 16 to 32 h after accelerated aging treatment. The amount of these mRNAs reached a maximum in 24 h imbibed seeds after the treatment. The accumulation of VrRH transcripts was shown to lead to the appearance of 25S and 18S rRNAs in the imbibed aging mung bean seeds. The results suggest that VrRHI may play a role in the viability of mung bean seeds.

A novel dimer of a C-type lectin-like heterodimer from the venom of Calloselasma rhodostoma (Malayan pit viper)

We have isolated a potent platelet aggregation inducer from the crude venom of Calloselasma rhodostoma (Malayan pit viper), termed rhodoaggretin, with a novel oligomeric structure consisting of a dimer of C-type lectin-like heterodimers. On the basis of its native molecular mass of 66 kDa, and a M(r) of 30 kDa for its disulfide-linked alphabeta-heterodimer, we propose that rhodoaggretin exists as a (alphabeta)2 complex in the native state. We postulate that the di-dimer is stabilized by non-covalent interactions as well as by an intersubunit disulfide bridge between the two alphabeta-heterodimers. This conclusion is based on the following observations: (a) sodium dodecylsulfate-polyacrylamide gel electrophoresis (SDS-PAGE) of the non-reduced rhodoaggretin gave a major 28 and a minor 52 kDa band. (b) Prior treatment of rhodoaggretin with a limited amount of 2-mercaptoethanol (2-ME; 0.1%) resulted in the complete abolishment of the 52 kDa band in SDS-PAGE. (c) Two-dimensional SDS-PAGE in the presence of 3% 2-ME showed that both the 28 and 52 kDa bands gave two bands each with M(r)s of 18 (alpha-subunit) and 15 (beta-subunit) kDa. (d) Mass spectrometric analyses showed that purified rhodoaggretin had a M(r) of 30155.39+/-3.25 Da while its s-pyridylethylated alpha- and beta-subunits had M(r)s of 16535.62+/-2.98 and 15209.89+/-1.61 Da respectively. These molecular weight data suggested the presence of 15 cysteinyl residues in rhodoaggretin as compared to the 14 that are reported for the heterodimeric C-type lectin-like proteins. This extra cysteinyl residue is a candidate for the formation of the intersubunit disulfide bond in the (alphabeta)2 complex. (e) Homology structural modeling studies showed that the extra cysteinyl residue can indeed form a disulfide bond that covalently links the two alphabeta-heterodimers as proposed above.

Proteomic investigation of metabolic shift in mammalian cell culture

Mammalian cells, under typical cultivation conditions, produce large quantities of lactate and ammonia that affect cell growth adversely and result in low cell concentration. Controlled nutrient feeding to maintain low concentrations of glucose and glutamine reduces metabolite production drastically, altering the metabolism of the cells. This metabolic shift results in higher cell concentration in continuous cultures and does not affect the specific productivity of the cells. We have taken a proteomics approach to investigate the differential protein expression with metabolic shift. Using two-dimensional gel electrophoresis (2-DE) and mass spectrometry (MS), we have found at least eight differentially expressed spots; two proteins were down-regulated, and the others were up-regulated with metabolic shift. These included metabolic enzymes, the brain form of phosphoglycerate mutase, which was down-regulated, and the precursor of the 23 kDa subunit of NADH-ubiquinone oxidoreductase, which was up-regulated. Another enzyme, the L1 isozyme of ubiquitin carboxyl-terminal hydrolase, which is involved in protein turnover and degradation, was also up-regulated in the metabolically altered cells. The remaining down-regulated spot had been identified as two isoforms of cytoplasmic actins, while three of the up-regulated spots were viral GAG polyproteins from various murine viruses. An unidentified protein was also up-regulated in the cells with altered metabolic state. This study shows the potential of using a proteomics approach in deciphering the intracellular changes in cells with physiological changes such as metabolism shift. The new insight into cell metabolism afforded by this analysis will greatly facilitate process optimization of continuous cell cultures.

Hepatocellular carcinoma: from bedside to proteomics

Hepatocellular carcinoma (HCC or hepatoma) is the most common primary cancer of the liver. It is responsible for approximately one million deaths each year, mainly in underdeveloped and developing countries. The aetiological factors identified in the development of HCC included persistent infection by hepatitis B and hepatitis C viruses, and exposure to aflatoxins. Although immunization can protect individuals from being infected by the hepatitis B virus, the early detection of HCC in those who have been infected by the virus remains a challenge. Thus most HCCs present late and are not suitable for curative treatment. Hence there is a tremendous interest and urgency to identify novel HCC diagnostic marker(s) for early detection, and tumour specific disease associated proteins as potential therapeutic targets in the treatment of HCC. Screening for these HCC proteins has been facilitated by proteomics, a key technology in the global analysis of protein expression and understanding gene function. Present and earlier proteome analyses of HCC have used predominantly experimental in vitro systems. The protein expression profiles of several hepatoma cell lines such as HepG2, Huh7, SK-Hep1, and Hep3B have been compared with normal liver, and nontransformed cell lines (Chang and WRL-68), while a comprehensive proteome analysis to create a protein database was carried out for the cell line HCC-M. In the future, proteome analyses utilizing tumour tissues, which reflect the pathological state of HCC more closely, will be undertaken. This work will complement the gene expression studies of HCC which are already underway. Efforts have also been directed at the proteome analysis of hepatic stellate cells, as these cells play an important role in liver fibrosis. Since liver fibrosis is reversible but not cirrhosis, it is of considerable importance to identify therapeutic targets that can slow its progression.

Environmental and developmental regulation of the wound-induced cell wall protein WI12 in the halophyte ice plant

A wounded gene WI12 was used as a marker to examine the interaction between biotic stress (wounding) and abiotic stress (high salt) in the facultative halophyte ice plant (Mesembryanthemum crystallinum). The deduced WI12 amino acid sequence has 68% similarity to WUN1, a known potato (Solanum tuberosum) wound-induced protein. Wounding, methyl jasmonate, and pathogen infection induced local WI12 expression. Upon wounding, the expression of WI12 reached a maximum level after 3 h in 4-week-old juvenile leaves, whereas the maximum expression was after 24 h in 8-week-old adult leaves. The temporal expression of WI12 in salt-stressed juvenile leaves was similar to that of adult leaves. The result suggests that a salt-induced switch from C3 to Crassulacean acid metabolism has a great influence on the ice plant's response to wounding. The expression of WI12 and the accumulation of WI12 protein were constitutively found in phloem and in wounded mesophyll cells. At the reproductive stage, WI12 was constitutively found in petals and styles, and developmentally regulated in the placenta and developing seeds. The histochemical analysis showed that the appearance of WI12 is controlled by both environmental and developmental factors. Immunogold labeling showed WI12 preferentially accumulates in the cell wall, suggesting its role in the reinforcement of cell wall composition after wounding and during plant development.

Identification of a serine protease inhibitor homologue in Bird's Nest by an integrated proteomics approach

For centuries, the edible nests of Collocalia spp. ("Bird's Nests") have been used as a Chinese delicacy that had been claimed to be an effective health-giving tonic. However, clinical studies indicated that in Singapore, Bird's Nest is the most common cause of food-induced anaphylaxis in children, which could lead to potentially life-threatening allergenic reactions. The purpose of this study was to characterize the major allergens in Bird's Nest by using the combined technologies of two-dimensional gel electrophoresis (2-DE), immunochemistry, N-terminal protein sequencing, and mass spectrometry. Results from the immunostaining of the Western blots of the Bird's Nest 2-DE separated proteins with the sera from allergic patients indicated the presence of a major allergen of 66 kDa. Initial searches of the matrix assisted laser desorption/ionization--time of flight--mass spectrometry (MALDI-TOF-MS) tryptic peptide masses of the allergen in the SWISS-PROT and NCBI nonredundant databases revealed that this protein was novel. Based on the partial protein sequence information obtained from N-terminal microsequencing and nanoelectrospray-tandem MS, the 66 kDa immunoreactive allergen was found to be homologous to ovoinhibitor, a Kazal-type serine protease inhibitor, which is one of the dominant allergens found in chicken egg white.

Proteome analysis of a human heptocellular carcinoma cell line, HCC-M: an update

Recently, we reported the proteome analysis of a human hepatocellular carcinoma cell line, HCC-M (Electrophoresis 2000, 21, 1787-1813), using two-dimensional gel electrophoresis (2-DE) and matrix assisted laser desorption/ionization-time of flight-mass spectrometry (MALDI-TOF-MS). From a total of 408 unique spots excised from the 2-DE gel, 301 spots yielded good MALDI spectra. Out of these, 272 spots had matches returned from the database search leading to the identification of these proteins. Here, we report the results on the identification of the remaining 29 spots using nanoelectrospray ionization-tandem mass spectrometry (nESI-MS/MS). First, "peptide tag sequencing" was performed to obtain partial amino acid sequences of the peptides to search the SWISS-PROTand NCBI nonredundant protein databases. Spots that were still not able to find any matches from the databases were subjected to de novo peptide sequencing. The tryptic peptide sequences were used to search for homologues in the protein and nucleotide databases with the NCBI Basic Local Alignment Search Tool (BLAST), which was essential for the characterization of novel or post-translationally modified proteins. Using this approach, all the 29 spots were unambiguously identified. Among them, phosphotyrosyl phosphatase activator (PTPA), RNA-binding protein regulatory subunit, replication protein A 32 kDa subunit (RP-A) and N-acetylneuraminic acid phosphate synthase were reported to be cancer-related proteins.