Japanese public health nurses classified based on empathy and secondary traumatic stress: variable-centered and person-centered approaches.

BACKGROUND: Healthcare providers frequently help traumatized people and are regularly exposed to indirect trauma from their work, resulting in negative psychological responses, such as secondary traumatic stress. Empathy has been associated with patient's quality of care and secondary traumatic stress among healthcare providers. However, the relationship between dispositional empathy and secondary traumatic stress has not been fully elucidated. This study used person- and variable-centered approaches to explore the nature of this relationship. METHODS: A total of 1,006 Japanese public health nurses working in the Tohoku region and Saitama prefecture completed questionnaires that included scales assessing dispositional empathy, secondary traumatic stress, and burnout. First, we examined predictors of secondary traumatic stress using multiple linear regression analysis. Then, we conducted a latent profile analysis to classify participants into unique groups based on four subscales of dispositional empathy (i.e., empathic concern, perspective taking, personal distress, fantasy) and secondary traumatic stress. Finally, we compared the mean values of the study variables across these groups. RESULTS: The multiple regression indicated that in those working in Saitama prefecture, lifetime traumatic experiences, work-related distress, and personal distress were positively related to secondary traumatic stress, but perceived support was negatively related to secondary traumatic stress. Latent profile analysis extracted four unique subgroups. Group 1 displayed the highest secondary traumatic stress levels. Group 2 was characterized by the highest level of empathic concern, personal distress, and fantasy and the lowest perspective taking. Group 3 had a moderate secondary traumatic stress level. Group 4 had the lowest secondary traumatic stress and personal distress scores. In these four groups, the burnout scale (exhaustion, cynicism, and professional efficacy) showed a pattern similar to the secondary traumatic stress scale. CONCLUSIONS: Our person-centered approach showed that this sample of public health nurses could be classified into four unique groups based on their empathy and secondary traumatic stress scores. Although this group of public health nurses was not large, one group displayed high personal distress levels and high secondary traumatic stress levels. Further research is needed to determine effective interventions for this group.

A rabbit model of fatal hypothyroidism mimicking "myxedema coma" established by microscopic total thyroidectomy.

Myxedema coma (MC) is a life-threatening endocrine crisis caused by severe hypothyroidism. However, validated diagnostic criteria and treatment guidelines for MC have not been established owing to its rarity. Therefore, a valid animal model is required to investigate the pathologic and therapeutic aspects of MC. The aim of the present study was to establish an animal model of MC induced by total thyroidectomy. We utilized 14 male New Zealand White rabbits anesthetized via intramuscular ketamine and xylazine administration. A total of 7 rabbits were completely thyroidectomized under a surgical microscope (thyroidectomized group) and the remainder underwent sham operations (control group). The animals in both groups were monitored without thyroid hormone replacement for 15 weeks. Pulse rate, blood pressure, body temperature, and electrocardiograms (ECG) were recorded and blood samples were taken from the jugular vein immediately prior to the thyroidectomy and 2 and 4 weeks after surgery. The thyroidectomized rabbits showed a marked reduction of serum thyroxine levels at 4 weeks after the surgical procedure vs. controls (0.50±0.10 vs. 3.32±0.68 µg/dL, p<0.001). Additionally, thyroidectomized rabbits exhibited several signs of hypothyroidism such as hypothermia, systolic hypotension, bradycardia, and low voltage on ECGs, compared with controls. Of the 7 rabbits with severe hypothyroidism, 6 died from 4 to 14 weeks after the thyroidectomy possibly owing to heart failure, because histopathologic examinations revealed a myxedema heart. In summary, we have established a rabbit model of fatal hypothyroidism mimicking MC, which may facilitate pathophysiological and molecular investigations of MC and evaluations of new therapeutic interventions.

A high concentration of triiodothyronine attenuates the stimulatory effect on hemin-induced erythroid differentiation of human erythroleukemia K562 cells.

Although thyroid hormone is a known stimulator of erythropoietic differentiation, severe anemia is sometimes observed in patients with hyperthyroidism and this mechanism is not fully understood. The aim of this study was to investigate the effect of triiodothyronine (T3) on hemin-induced erythropoiesis. Human erythroleukemia K562 cells were used as an erythroid differentiation model. Cell differentiation was induced by hemin and the effect of pre-incubation with T3 (0.1 to 100 nM) was analyzed by measuring the benzidine-positive rate, hemoglobin content, CD71 expression (transferrin receptor), and mRNA expression for transcription factors related to erythropoiesis and thyroid hormone receptors (TRs). Hemin, a promoter of erythroid differentiation, increased the levels of mRNAs for TRα, TRß, and retinoid X receptor α (RXRα), as well as those for nuclear factor-erythroid 2 (NFE2), GATA-binding protein 1 (GATA1) and GATA-binding protein 2 (GATA2). Lower concentrations of T3 had a stimulatory effect on hemin-induced hemoglobin production (1 and 10 nM), CD71 expression (0.1 nM), and α-globin mRNA expression (1 nM), while a higher concentration of T3 (100 nM) abrogated the stimulatory effect on these parameters. T3 at 100 nM did not affect cell viability and proliferation, suggesting that the abrogation of erythropoiesis enhancement was not due to toxicity. T3 at 100 nM also significantly inhibited expression of GATA2 and RXRα mRNA, compared to 1 nM T3. We conclude that a high concentration of T3 attenuates the classical stimulatory effect on erythropoiesis exerted by a low concentration of T3 in hemin-induced K562 cells.

Triiodothyronine suppresses activin-induced differentiation of erythroleukemia K562 cells under hypoxic conditions.

Thyroid hormone stimulates erythropoietic differentiation. However, severe anemia is sometimes seen in patients with hyperthyroidism, and the mechanisms have not been fully elucidated. Bone marrow is comprised about 2-8% oxygen, and the characteristics of hematopoietic stem cells have been shown to be influenced under hypoxia. Hypoxia-inducible factor-1 is a critical mediator of cellular responses to hypoxia and an important mediator in signal transduction of thyroid hormone [triiodothyronine (T3)]. The aim of this study was to investigate the effect of T3 on erythropoiesis under hypoxia mimicking physiological conditions in the bone marrow. We maintained human erythroleukemia K562 cells under hypoxic atmosphere (2% O2) and examined their cellular characteristics. Compared to that under normal atmospheric conditions, cells under hypoxia showed a reduction in the proliferation rate and increase in the hemoglobin content or benzidine-positive rate, indicating promotion of erythroid differentiation. T3 had no effect on hypoxia-induced erythroid differentiation, but significantly inhibited activin A/erythroid differentiation factor-induced erythroid differentiation. Moreover, GATA2 mRNA expression was suppressed in association with erythroid differentiation, while T3 significantly diminished that suppression. These results suggest that T3 has a direct suppressive effect on erythroid differentiation under hypoxic conditions.

Improved survival rate by temperature control at compression sites in rat model of crush syndrome.

BACKGROUND: Crush syndrome (CS) has been reported in disasters, terrorist incidents, and accidents, and the clinical and pathologic picture has gradually been clarified. Few lethal and reproducible animal models of CS with use of a quantitative load are available. A new model is needed to investigate pathologic and therapeutic aspects of this injury. MATERIALS AND METHODS: Using a device built from commercially available components, both hindlimbs of anesthetized rats were respectively compressed for 6 h using 3.6-kg blocks. The effects of trunk warming alone without compressed hindlimbs (Group A), non-warming at room temperature (Group B), whole-body warming including compressed hindlimbs (Group C), or warming of compressed hindlimbs alone (Group D) during compression were examined. Survival rates were compared and hematological and histologic analyses were performed at specific time points after compression release. RESULTS: Limb or whole-body warming significantly worsened the survival of rats. We found a much lower survival rate of 0%-10% in animals, in which the hindlimbs were warmed during compression (Groups C and D) at 12 h after compression release, compared with 90%-100% in animals without warming of the hindlimbs (Groups A and B). Groups C and D showed significantly enhanced hyperkalemia at ≥4 h after compression release and all blood samples from dead cases showed hyperkalemia (>10 mEq/L). CONCLUSIONS: We developed a new lethal and reproducible rat CS model with a quantitative load. This study found that warming of compressed limbs worsened the survival rate and significantly enhanced hyperkalemia, apparently leading to cardiac arrest.

The effect of hydrogen gas on a mouse bilateral common carotid artery occlusion.

In recent studies, molecular hydrogen selectively reduced the levels of hydroxyl radicals in vitro and exerted a therapeutic anti-oxidant activity in a rat middle cerebral artery occlusion model. The aim of this study was to investigate the effect of hydrogen gas on a mouse bilateral common carotid artery occlusion (BCCAO) model. Male C57BL/6J mice were subjected to transient BCCAO with a nontraumatic aneurysm clip. The mice were divided into three groups: sham, BCCAO, and BCCAO treated with 1.3 % hydrogen gas. Cerebral blood flow (CBF) in the cortex was measured sequentially for both hemispheres with a non--invasive and noncontact laser Doppler blood perfusion imager during the procedure. Vital signs were also recorded. Oxidative stress evaluated by measuring the level of 8-hydroxy-2'-deoxyguanosine (8-OHdG), neuronal injury in the hippocampal CA1 sector, and brain water content were assessed 24 h after ischemia. The hydrogen gas treatment had no significant effect on vital signs or CBF values. However, the reduction of the expression of 8-OHdG, the decrease in the neuronal injury in the hippocampal CA1 sector, and the attenuation in brain water content were observed in hydrogen-treated mice. In conclusion, hydrogen gas might be effective in a mouse BCCAO model.

An isolation and confinement facility for the selection of astronaut candidates.

BACKGROUND: In 2008, JAXA conducted its fifth astronaut candidate recruitment. The final stage involved 10 of 963 applicants undergoing the first and second examination stages based on physical checks, written tests, and interviews. The third (final) stage focused on evaluating the behavioral attitudes required for ISS crewmembers. Since it is difficult to assess these attitudes by paper testing or interview alone, JAXA has established an environment in which the assessors could observe the behavior of examinees on a continuous basis. METHODS: The 10 examinees stayed in the isolation and confinement facility for 1 wk. During their stay, several group and personal tasks were assigned along with predetermined daily schedules covering aspects of leadership, teamwork ability, productivity (performance), and so on. Subsequently, psychologists, psychiatrists, and JAXA officials/managers experienced in practical human space development evaluated them. RESULTS: During the confinement, no examinees showed any excessive character traits or psychopathologic behavior. Repeated observations led to a convergence of opinions among the experts. Three examinees ultimately passed this assessment and were assigned as new Japanese astronaut candidates. DISCUSSION: This unique assessment enabled the assessors to conduct longitudinal evaluations, evaluations based on observing detailed behavior, and easy control of test conditions and safety. Although "selection of the right stuff" may differ among each space agency, this method offers the unique advantage of allowing experts in various fields to evaluate the competencies of examinees both synthetically and longitudinally.

[Psychological trauma risks among disaster workers: perspectives on their mental health following the Great East Japan Earthquake].

Following the March 11, 2011 Great Japan East Earthquake and the Fukushima Daiichi Nuclear Power Plant accident, disaster workers have been working day and night for recovery efforts. A large part of disaster workers, i.e., Self-Defense Force, police, fire department, and coast guard personnel, were highly acknowledged by the Japanese public for searching nearly 19,000 dead or missing victims. This recognition will be beneficial for their psychological recovery. On the other hand, dentists and government employees also took a large role in these mortuary missions, but their work was hardly known to the people. Furthermore, local government employees became victims of public criticisms. Similar phenomenon has been seen among Fukushima nuclear plant workers. These workers have experienced a whole array of traumatic stress, including near-death work experiences, irradiation fear, loss of their properties and their loved ones. The electric company has been blamed by the public for their disaster responses, so the public portrays these employees as disaster perpetrators. However, this trend is leading to serious discriminations and harassments, and adversely affecting their mental health. We all hope the recovery efforts to complete as soon as possible. However, when people criticize these workers, their burden of psychological trauma will continue to grow, and their recovery process will be impeded. It is crucial for the society to recognize these hard-working people and to show appreciation and support for their dedications.

[Complexities of the stress experienced by employees of the Fukushima nuclear plants].

Fukushima Daiichi Nuclear Power Plants suffered serious damage by the Great East Japan Earthquake and Tsunami. The employees of the plant worked very hard to stabilize the nuclear reactor and to prevent any secondary accidents. They were in one of the most severe situations in this disaster, but they were the people who hesitated most to request help for themselves. We started visiting the Fukushima Daini Plant office that was used as the frontline base for Daiichi Plant workers since July, 2011. These visits were held once or twice a month and we offered mental health support to the employees. We have completed interview with the total number of 339 plant workers by April, 2012. We offered several ways of mental support including clinical treatment, continuous counseling, or one time advice, depending on mental condition of each interviewee. Complexity of huge disaster and individuality of suffering from it were discussed in this article. Like local residents, many plant workers also experienced death/missing of family, loss of housing, refuge life, and dispersion of family. Furthermore, they have been suffering from various kinds of criticism and slander against Tokyo Electric Power Company. Many workers, even though they were not in management positions, seemed to have guilty conscience and sense of responsibility that forced them to stay in the risky working site. We could find some struggling coexistence of sense of guilt (as a causer of disaster) and sense of victim in their mind. It was suggested that continuous effort to listen and pay attention to their talk is important in order to support their mission to stabilize the power plant and to prevent them from over-stress and burnout.

Validity and reliability of the Secondary Traumatic Stress Scale-Japanese version.

AIM: This study assessed the validity and reliability of the Secondary Traumatic Stress Scale-Japanese Version. METHODS: The original Secondary Traumatic Stress Scale was translated into Japanese, and Japanese items were back-translated to English to confirm the accuracy of the translation. A total of 870 public health nurses from the Tohoku region in Japan completed the Secondary Traumatic Stress Scale-Japanese Version. An exploratory factor analysis was conducted to identify the number of components. Moreover, 351 public health nurses from the Saitama prefecture in Japan also completed the scale. A confirmatory factor analysis was performed with the factor structure identified in the exploratory factor analysis. RESULTS: The exploratory factor analysis identified two components: one associated with client-related distress and the other with trauma-related distress. The confirmatory factor analysis confirmed the two-factor structure. The two-factor structure model was better than the three-factor model presented in the original validation study for the English version of the scale. The two-factor model had good internal consistency for the overall product and the subscales. Pearson correlations showed that this model had good convergent validity against the Maslach Burnout Inventory, a psychological measure similar to the Secondary Traumatic Stress Scale. Finally, the two-factor model had good discriminant validity against the Maslach Burnout Inventory. CONCLUSION: This study identified two components of the Secondary Traumatic Stress Scale-Japanese Version that differ from the three components found in the original English version. The differences in the factor structure might indicate that the factor structure was culturally influenced.

International Space Station medical standards and certification for space flight participants.

INTRODUCTION: The medical community of the International Space Station (ISS) has developed joint medical standards and evaluation requirements for Space Flight Participants ("space tourists") which are used by the ISS medical certification board to determine medical eligibility of individuals other than professional astronauts (cosmonauts) for short-duration space flight to the ISS. These individuals are generally fare-paying passengers without operational responsibilities. MATERIAL AND CONTEXT: By means of this publication, the medical standards and evaluation requirements for the ISS Space Flight Participants are offered to the aerospace medicine and commercial spaceflight communities for reference purposes. It is emphasized that the criteria applied to the ISS spaceflight participant candidates are substantially less stringent than those for professional astronauts and/or crewmembers of visiting and long-duration missions to the ISS. CONCLUSIONS: These medical standards are released by the government space agencies to facilitate the development of robust medical screening and medical risk assessment approaches in the context of the evolving commercial human spaceflight industry.

Protective effect of inhalation of hydrogen gas on radiation-induced dermatitis and skin injury in rats.

The effect of inhalation of hydrogen-containing gas (1.3% hydrogen + 20.8% oxygen + 77.9% nitrogen) (HCG) on radiation-induced dermatitis and on the healing of healing-impaired skin wounds in rats was examined using a rat model of radiation-induced skin injury. An X-ray dose of 20 Gy was irradiated onto the lower part of the back through two holes in a lead shield. Irradiation was performed before or after inhalation of HCG for 2 h. Inhalation of HCG significantly reduced the severity of radiodermatitis and accelerated healing-impaired wound repair. Staining with terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) and 8-hydroxy-2(')-deoxyguanosine (8-OHdG) showed that the proportion of apoptotic keratinocytes and the level of staining in the X-irradiated skin of rats that pre-inhaled HCG were significantly lower than that of rats which did not pre-inhale HCG. Cutaneous full-thickness wounds were then created in the X-irradiated area to examine the time-course of wound healing. X-irradiation significantly increased the time required for wound healing, but the inhalation of HCG prior to the irradiation significantly decreased the delay in wound healing compared with the control and post-inhalation of HCG groups. Therefore, radiation-induced skin injury can potentially be alleviated by the pre-inhalation of HCG.

Low oxygen tension enhances proliferation and maintains stemness of adipose tissue-derived stromal cells.

Recent evidence indicates that low oxygen tension or hypoxia alters the characteristics of stem cells. The actions of hypoxia are mediated through the hypoxia-inducible factor, a critical mediator of the cellular response to hypoxia. Adipose tissue-derived stromal cells (ASCs) are one of the most promising cell sources for tissue engineering applications. This study investigated the effect of hypoxia on ASCs in terms of the ability to proliferate and differentiate. ASCs were extracted from mice and maintained under hypoxic atmosphere (2% O2) for up to eight in vitro passages. The proliferation rate was examined as a growth curve, and the potency of differentiation was evaluated. To investigate the cell characteristics, we checked several stem-cell markers and growth factors. Compared with the normoxic state (20% O2), hypoxia enhances proliferation with an approximately six- to sevenfold higher ASC expansion over 6 weeks. The expression of Oct3/4 and Nanog (stem-cell marker) and the amount of secreted growth factors were increased under the hypoxic condition. These results suggest that low oxygen tension enhances proliferation and maintains stemness of ASCs. Thus, this study emphasizes the profitability of hypoxic culture for expansion of ASCs and maintenance of their undifferentiated state for further therapeutic use.

Therapeutic effect of exendin-4, a long-acting analogue of glucagon-like peptide-1 receptor agonist, on nerve regeneration after the crush nerve injury.

Glucagon-like peptide-1 (GLP-1) is glucose-dependent insulinotropic hormone secreted from enteroendocrine L cells. Its long-acting analogue, exendin-4, is equipotent to GLP-1 and is used to treat type 2 diabetes mellitus. In addition, exendin-4 has effects on the central and peripheral nervous system. In this study, we administered repeated intraperitoneal (i.p.) injections of exendin-4 to examine whether exendin-4 is able to facilitate the recovery after the crush nerve injury. Exendin-4 injection was started immediately after crush injury and was repeated every day for subsequent 14 days. Rats subjected to sciatic nerve crush exhibited marked functional loss, electrophysiological dysfunction, and atrophy of the tibialis anterior muscle (TA). All these changes, except for the atrophy of TA, were improved significantly by the administration of exendin-4. Functional, electrophysiological, and morphological parameters indicated significant enhancement of nerve regeneration 4 weeks after nerve crush. These results suggest that exendin-4 is feasible for clinical application to treat peripheral nerve injury.

Effects of platelet-rich plasma-containing fragmin/protamine microparticles in enhancing endothelial and smooth muscle cell growth and inducing collateral vessels in a rabbit model of hindlimb ischemia.

The purpose of the study was to evaluate the effects of isogenous platelet-rich plasma (PRP)-containing fragmin/protamine microparticles (F/P MPs) as a delivery system for proteins in PRP on growth of endothelial and smooth muscle cells (SMCs) in vitro and as an alternative treatment for peripheral arterial disease (PAD) and critical limb ischemia. Frozen and thawed PRP contains high concentrations of growth factors that are adsorbed by F/P MPs. Human aorta endothelial cells (AECs) and SMCs were grown in a medium with PRP. Addition of F/P MPs significantly enhanced the proliferative effects of PRP on AECs and SMCs at 37 °C for >10 days. Intramuscular administration of phosphate-buffered saline (PBS; 2 mL, control), F/P MPs (12 mg in 2 mL PBS), PRP (2 mL), or PRP (2 mL) containing F/P MPs (12 mg) was then performed in a rabbit model of hindlimb ischemia prepared by resection of the left femoral artery. Blood flow and pressure were measured on days 0, 14, and 28, and angiography to assess arteriogenesis was performed on day 28. PRP-containing F/P MPs strongly induced functional collateral vessels in the rabbit model of hindlimb ischemia, indicating possible use of these microparticles in therapy for PAD.

Effect of hydrogen gas on the survival rate of mice following global cerebral ischemia.

Global cerebral ischemia and reperfusion (I/R) often result in high mortality. Free radicals have been reported to play an important role in global cerebral I/R, and therefore, reduction of these might improve the outcome. Here, we investigated the effect of hydrogen gas (H2) (a strong free radical scavenger) on the survival rate of mice following global cerebral I/R. We further examined the histopathological outcome and also the brain water content (as a possible determinant of mortality). Male C57BL/6J mice were subjected to global cerebral I/R by means of 45-min bilateral common carotid artery occlusion (BCCAO). A total of 160 mice were divided into three groups: sham surgery (sham group), BCCAO without H2 (BCCAO group), and BCCAO treated with 1.3% H2 (BCCAO + H2 group). We observed that H2 treatment significantly (P = 0.0232) improved the 7-day survival rate of mice, from 8.3% (BCCAO group, n = 12) to 50% (BCCAO + H2 group, n = 10). Histopathological analysis revealed that H2 treatment significantly attenuated neuronal injury and autophagy in the hippocampal cornu ammonis 1 sector and also brain edema, after 24 h of reperfusion. The beneficial effects of H2 treatment on brain injury were associated with significantly lower levels of oxidative stress markers (8-hydroxy-2'-deoxyguanosine and malondialdehyde) in the brain tissue. Thus, we believe that H2 may be an effective treatment for global cerebral I/R.

Therapeutic effect of paroxetine on stress-induced gastric lesions in mice.

Compared to the well-known anti-ulcerogenic properties of tricyclic antidepressants, the impact of selective serotonin reuptake inhibitors (SSRIs) on gastric mucosa is less clear. Human clinical trials have shown that SSRIs and non-steroidal anti-inflammatory drugs (NSAIDs) act synergistically and promote stomach ulcer formation and upper gastrointestinal tract bleeding. Acute SSRI treatment confers an additional risk for the formation of NSAID-induced gastric ulcers through increase in gastric acid secretion. Stress, which is often experienced by depressed patients, also deteriorates the gastric environment. Thus the potential for exacerbating stress-induced gastric lesions must be considered before prescribing SSRIs. Therefore, we evaluated the effects of paroxetine by using a water-immersion stress-induced stomach ulcer model of mice, by examining single vs. repeated paroxetine treatments for 8 and 22 days before stress induction. Repeated administration of paroxetine significantly decreased the area of stress-induced stomach lesions. Although stress significantly increased the serum corticosterone concentrations, the levels were not affected by the 8-day paroxetine treatment. We confirmed the anxiolytic and antidepressive effects of 8-day paroxetine treatment at 1 and 5 days after stress induction by using the elevated plus-maze and tail-suspension tests. We concluded that repeated paroxetine treatment significantly attenuates the stress-induced ulcerogenic process in the stomach.