Social Frailty and Functional Status in Japanese Older Adults: The Mediating Role of Subjective Cognitive Function

OBJECTIVE

This study aimed to explore the direct and indirect effects of social frailty on functional state trajectories mediated by subjective cognitive function in older adults.

DESIGN

Longitudinal study.

SETTING AND PARTICIPANTS

Overall, 514 adults aged ≥65 years living in a suburban area of central Japan were included in this study.

METHODS

Five-item social frailty index (going out, visiting, feeling helpful, living alone, and talking to others), subjective cognitive function from the Kihon Checklist, and instrumental activities of daily living disability. Latent growth curve models were applied to examine the longitudinal relations among the variables.

RESULTS

During the 6-year follow-up in latent growth curve models, the initial level of social frailty in older adults was negatively associated with that of functional status (β = -0.53, P < .001), and the rate of change in social frailty was negatively associated with that in functional status (β = -0.78, P < .001). In the mediation model, the indirect effect from the social frailty level to functional status level through subjective cognitive function level was significant (β = -0.14, 95% CI -0.29, -0.09); the rates of change in subjective cognitive function mediated the relationship between those in social frailty and functional status (β = -0.35, 95% CI -0.46, -0.25).

CONCLUSIONS AND IMPLICATIONS

This study found that there is an association between social frailty and functional status in Japanese older adults. Subjective cognitive function mediated this relationship. Hence, additional research is required to investigate additional potential factors linking social frailty and functional status in order to gain a better understanding of the underlying mechanisms.

Longitudinal assessment of the relationship between frailty and social relationships among Japanese older adults: a random intercept cross-lagged panel model

OBJECTIVES

This study aimed to explore the bidirectional association between frailty and social relationships in older adults while distinguishing between interpersonal and intrapersonal effects.

METHODS

A prospective cohort study of community-dwelling older adults was conducted in Japan in three waves spanning six years with follow-ups in every three years. Random intercept cross-lagged panel model was used to explore temporal associations between frailty and social relationships.

RESULTS

Data for 520 participants (mean age 73.02 [SD 6.38] years, 56.7% women) were analyzed. Across individuals, frailty was associated with social relationships (β = -0.514, p < 0.001). At the interpersonal level, frailty was cross-sectionally associated with social relationships separately at T1(β = -0.389, p < 0.01), T2 (β = -0.343, p < 0.001) and T3 (β = -0.273, p < 0.05). Moreover, social relationships were associated with subsequent increases in symptoms of frailty in all measurement waves (β = -0.332, p < 0.001; β = -0.169, p < 0.01) and vice versa (β = -0.149, p < 0.05; β = -0.292, p < 0.001).

CONCLUSIONS

The results suggest that frailty was associated with lower levels of social relationships. Frailty improvement programs can be combined with interventions to enhance social relationships, which will be beneficial in preventing frailty. The results emphasize the importance of combining clinical treatments of frailty with interventions to improve social relationships.

Estimating rainfall interception loss of three dominant shrub species in an oasis-desert ecotone using in situ measurements and the revised Gash analytical model

Canopy interception loss affects the local water budget by removing a non-negligible proportion of rainfall from the terrestrial surface. Thus, quantifying interception loss is essential for thoroughly understanding the role of vegetation in the local hydrological cycle, especially in dryland ecosystems. However, sparse shrubs in dryland ecosystems have not been sufficiently studied, owing to time- and labor-intensive field experiments and challenging model parameterization. In this work, 4-year growing season field experiments on rainfall partitioning were conducted for three dominant shrub species (Haloxylon ammodendron, Nitraria sphaerocarpa, and Calligonum mongolicum) in an oasis-desert ecotone in northwestern China. The revised Gash analytical model was well parameterized, which reliably simulated the cumulative interception loss for sparse shrubs, and the validated model performed better for H. ammodendron, followed by C. mongolicum and N. sphaerocarpa, with relative errors of 8.4%, 15.4%, and 23.9%, respectively. The mean individual interception loss percentage for H. ammodendron (28.4%) was significantly higher than that for C. mongolicum (11.0%) and N. sphaerocarpa (10.9%) (p < 0.05), which could be ascribed to the higher canopy storage capacity and wet-canopy evaporation rate of H. ammodendron. For all shrub species, the majority proportion of interception loss occurred during canopy saturation and drying-out periods, accounting for approximately 79-85% of the cumulative interception loss. Overall, the mean local interception loss of three dominant shrub species in the ecotone removed nearly 17% of the corresponding cumulative rainfall during the growing season. These results not only provide methodological references for estimating the interception loss of sparse vegetation in dryland ecosystems, but also provide scientific insights for water resource management and ecosystem restoration in water-limited regions similar to the experimental site.

Latent Subtype of Cognitive Frailty among Multimorbidity Older Adults and Their Association with Social Relationships

This study aimed to explore all the relevant subtypes of cognitive frailty among Japanese community-dwelling older adults with multimorbidity. Moreover, it examined the associations between these potential subtypes of cognitive frailty and social relationships. This study targeted relevant cross-sectional data regarding community-based older adults with multimorbidity. It employed a person-centered method to perform a latent class analysis and explore the subtypes of cognitive frailty among older adults. Moreover, a multinominal logistic regression analysis was employed to examine the association between potential subtypes of cognitive frailty and social relationships. Data for 396 participants (mean age, 75.8 [SD, 7.3] years; 51.3% females) were analyzed. Three cognitive frailty subtypes were subsequently revealed: the robust group (42.0%), the group with partial cognitive frailty (38.6%), and the group with cognitive frailty (19.4%). People with high levels of social relationships were more likely to be in the robust and the partial cognitive frailty groups. This study identified different subtypes of cognitive frailty among multimorbid older adults and highlighted the significance of social relationships. These findings could serve as a reference for conceptualizing cognitive frailty through the person-centered method. Promoting a high level of social relationships could be useful to prevent the cognitive frailty among older adults with multimorbidity.

Experimental partitioning of rainfall into throughfall, stemflow and interception loss by Haloxylon ammodendron, a dominant sand-stabilizing shrub in northwestern China

Rainfall partitioning by the vegetation canopy represents a significant component of the local hydrological cycle by reshaping the amount and spatial distribution of rainfall. Measuring the components of rainfall partitioning, however, has been a challenging task due to laborious- and time-consuming field experiments. In this study, to probe the influences of long-term afforestation on dynamic patterns of rainfall partitioning, the dominant sand-stabilizing shrub Haloxylon ammodendron at three different ages was selected for field measurements during the 2020-2021 growing season. The throughfall percentage for young H. ammodendron (YH, 75.9 %) was significantly higher than that for middle-aged H. ammodendron (MAH, 63.4 %) and mature H. ammodendron (MH, 62.4 %) (p < 0.05 for all cases). However, the interception loss percentage of YH (22.3 %) was significantly lower than that for MAH (35.0 %) and MH (36.5 %) (p < 0.05 for all cases). No significant difference was found for stemflow percentage among YH (1.8 %), MAH (1.5 %) and MH (1.1 %). Smaller rainfall events contributed to a higher interception loss percentage and a lower net rainfall percentage for all ages. Both throughfall and stemflow percentage first showed increasing trends and then tended to be stable with increasing rainfall amount and duration, whereas interception loss percentage showed the opposite patterns. Rainfall partitioning was significantly correlated with the plant area index, stem basal area and canopy height (p < 0.05 for all cases), which may account for significant differences in rainfall partitioning patterns, as all shrubs experienced the same weather conditions. The average funneling ratio was 56.6, 26.7 and 17.9 for YH, MAH and MH, respectively. These results suggested that H. ammodendron afforestation can have a significant impact on rainfall partitioning by reducing net rainfall reaching the soil and may have some implications for local water budget and ecosystem management in oasis-desert ecotones.

Social Relationships and Onset of Functional Limitation among Older Adults with Chronic Conditions: Does gender matter?

Objectives

This study aimed to examine the longitudinal association between social relationships and physical functioning among community-dwelling older adults with chronic conditions.

Methods

Self-reported questionnaires were distributed and collected between 2014 and 2017 from participants ≥65 years old. The Index of Social Interaction was used to evaluate social relationships and the instrumental activities of daily living (IADL) subscale of the Tokyo Metropolitan Institute of Gerontology Index of Competence was used to examine functional status.

Results

A total of 422 participants (190 males and 232 females) were included in the final analysis. High social relationships demonstrated significant adverse effects (odds ratio [OR] = 0.77, 95% confidence interval [CI]: 0.64-0.93) on the decline of IADL in the overall sample, particularly for females (OR = 0.71, 95% CI: 0.55-0.93) but not as much for males (P = 0.131).

Conclusion

This finding suggests that functional limitation was influenced by social relationships among disabled older adults and the influence of social relationships on functional limitation differed based on gender.

Patterns of Movement Performance among Japanese Children and Effects of Parenting Practices: Latent class analysis

Objectives

This study aimed to examine the long-term effects of parenting practice during preschool years on children's movement performance in primary school.

Methods

This three-year longitudinal study included 225 children aged 3-6-years-old. Parents reported baseline parenting practice and evaluated children's movement performance three years later. Latent class analysis was used to explore latent classes of movement performance. A post hoc test was used to identify the characteristics of different patterns. Finally, adjusted multinomial logistic regression models were used to test the influence of parenting practice on identified patterns of movement performance.

Results

Children in this study were grouped into three movement performance patterns, labelled as 'least difficulties' (n = 131, 58.2%), 'low back pain' (n = 68, 30.2%) and 'most difficulties' (n = 26, 11.6%). After controlling for age, gender, having siblings or not, family structure, standardised body mass index, sleep condition and dietary habits, the researchers found that if parents played games with children frequently, the children would have a 0.287 times lower probability of being in the 'low back pain' class (95% confidence interval [CI]: 0.105-0.783). In addition, if parents take children to meet peers of a similar age frequently, children would have a 0.339 times lower probability of being in 'most difficulties' class (95% CI: 0.139-0.825).

Conclusion

Primary healthcare providers should pay careful attention to children with movement difficulties. The study provides longitudinal evidence to support the applicability of positive parenting practice in early childhood to prevent children's movement difficulties.

Role of Multifaceted Social Relationships on the Association of Loneliness with Depression Symptoms: A Moderated Mediation Analysis

Strong relationship exists between loneliness and depression in older adults. However, the effect of multifaceted social relationships on the relationship between loneliness and depression has not been explored. The purpose of the current study was to find out how multifaceted social relationships affect the aforementioned processes. We investigated and evaluated the loneliness status, depression symptoms, social relationships, and demographic information of 1116 older adults aged ≥65 years living in rural Japan. The final 555 participants were included in the analysis. Statistical evidence showed a direct effect between loneliness and depression symptoms. Additionally, the mediation model found that social curiosity and participation acted as mediators between loneliness and depression symptoms. Further, independence and participation, independence, and feeling safe played a conditional moderating role in the model of loneliness-social curiosity-depression symptoms and loneliness-participation-depression symptoms, respectively. Interaction can be an individual moderator in the link between loneliness and depression symptoms without any mediator. The moderated mediation model suggests that social curiosity and participation could mediate the association between loneliness and depression symptoms. In this process, independence, participation, and feeling safe may act as moderators.

Measurement invariance and country difference in children's social skills development: Evidence from Japanese and Chinese samples

The diversity of child social skills development is not well detected among Asian countries. Culturally validated assessments are needed for practitioners to evaluate child social skills. This study tested the measurement invariance of the Social Skill Scale (SSS) across Japanese and Chinese samples and explored country differences in child social skills development. The SSS utilizes a widely used factor structure (assertion, self-control, and cooperation subdomains) and has established Japanese and Chinese versions. We conducted investigations with an identical process and materials with different language versions, collecting data from 931 Japanese kindergarten children (Mage = 4.35, SDage = 1.07; 53.6% boys) and from 1130 Chinese kindergarten children (Mage = 4.47, SDage = 1.00; 52.3% boys). We used multiple confirmatory factor analysis to test measurement invariance of the SSS and established the validity, reliability, and scalar measurement invariance for the first-order factor structure of the SSS across the two country samples. We also examined country differences on the associations between demographics, parenting practice, and child social skills development. We found that, compared to the Chinese sample, cooperation skills significantly increased more with age among the Japanese sample. However, spanking was negatively related to self-control skills development in both countries. Our findings contribute to the demonstration of the diversity of child social skills development and have important implications for assessing and developing child social skills using culture-specific strategies.

Vibration modes of a transportable optical cavity

Many factors still need to be evaluated to fully understand the physical mechanisms determining optical cavity vibration, which are crucial for designing and constructing a transportable ultra-stable laser. Herein, a detailed dynamic analysis is used to characterize the vibration modes of a transportable optical cavity. The first five resonance modes are identified in the presence of a cavity support, and the guidelines to achieve a high first-order resonance frequency are proposed; thereby, high robustness is described using a 50 mm length optical cavity. The results demonstrate that the first-order resonance of up to 681 Hz with a gross weight of 2.51 kg can be achieved using an optimization strategy for given cavity support. The theoretical results are consistent with simulation and experiment. With the optimal group, a 1.34 Hz linewidth transportable ultra-stable laser at 1550 nm is established, and a linewidth of 1.5 Hz and frequency instability of 9.5×10^-15@1s are obtained after the test including 100 km actual road transportation and 34 min continuous vibration. The test condition is equivalent to ∼ 1000 km road transportation. Our method can be readily extended to other transportable optical cavities, providing a powerful tool for improving the robustness of vibration, particularly important for transportable environments.

Multimorbidity and functional limitation: the role of social relationships

OBJECTIVES

To examine the relationship between multimorbidity and functional limitation, and how social relationships alter that association.

METHODS

This cross-sectional study used data collected by self-reported questionnaires from adults aged 65 years and older living in a rural area in Japan in 2017. This analysis included complete data from 570 residents. Multimorbidity status was defined as having two chronic diseases exist simultaneously in one individual, and the function status was measured by their long-term care needs. Social relationships were assessed by the Index of Social Interaction and divided into high and low levels. Multiple logistic regression analysis was used to examine the association between social relationships and functional limitation and to assess the role of social relationships in this association.

RESULTS

The logistic regression model indicated that the risk of functional limitation was higher in multimorbidity participants than free-of-multimorbidity participants (OR = 2.55, 95% CI = 1.56-4.16). Compared with participants with no multimorbidity and a high level of social relationships, low level of social relationships increased the risk of functional limitation among participants both with and without multimorbidity, with the OR = 7.71, 95% CI = 3.03-19.69 and OR = 3.28, 95% CI = 1.30-8.27, respectively. However, no significant result was found in participants with multimorbidity and a high level of social relationships (P = 0.365).

CONCLUSIONS

Multimorbidity was associated with functional limitations. However, this association could be increased by a low level of social relationships and decreased by a high level of social relationships.

Nephroprotective effect of wogonin against cadmium-induced nephrotoxicity via inhibition of oxidative stress-induced MAPK and NF-kB pathway in Sprague Dawley rats

Oxidative stress (OS) is one of the responsible factors for causing renal diseases. For the treatment or prevention of the renal disease, antioxidants use could be a hopeful therapeutic mediation as they block the oxidative reaction along with inflammatory process. Wogonin (Wog) is a plant flavonoid, a pharmacologically active component of Scutellaria baicalensis Georgi (Huang Qui), which exhibits antioxidant activity. In this investigation, we explored the nephroprotective activity of Wog on cadmium (Cd)-induced nephron toxicity in rats. Administering (10 and 20 mg/kg) intraperitoneally diminished Cd-induced anomalies in kidney histology and creatinine and serum urea levels. Wog therapy reduced the Cd-influenced generation of inflammatory mediators, inclusive of tumor necrosis factor alpha, interleukin 6, and interleukin 1 beta. Western blot analysis demonstrated that Wog abolished proinflammatory nuclear factor-kappa B (NF-κB) p65 stimulation, phosphorylation of p38 mitogen-activated protein kinases (MAPKs). In all, Wog demonstrated antioxidative and anti-inflammatory effects in Cd- intoxicated rats by obstructing OS and activation of NF-κB via restricting the stimulation of upstream kinases inclusive of MAPKs.

Concentrated Growth Factors Can Inhibit Photoaging Damage Induced by Ultraviolet A (UVA) on the Human Dermal Fibroblasts In Vitro

BACKGROUND Photoaging is the main cause of extrinsic skin aging. Daily exposure to ultraviolet A (UVA) accelerates the process of photoaging. The present study aimed to understand the role of concentrated growth factors (CGF) on UVA irradiated human skin cells. MATERIAL AND METHODS We isolated and subcultured normal human dermal fibroblasts (NHDFs) from 6 different human dorsal skins and established photoaging models of NHDFs irradiated by UVA to detect the influence of CGF on fibroblasts in vitro. Three groups were examined: normal, cellular photoaging model (total dosages of 18J·cm--⁻²-), and cellular photoaging model plus CGF. In our study, we used the MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) assay method to measure the cell viability. We also used reactive oxygen species (ROS) assay and superoxide dismutase (SOD) assay to measure respectively the amount of oxygen free radicals and antioxidative enzymes. We compared the migration rates among the photoaging model groups, the control groups, and the CGF-treated culture medium groups that were irradiated. RESULTS Our study results indicated that 5% CGF can reduce UVA-induced human skin fibroblasts damage significantly, improve the viability of NHDFs significantly, and largely decrease the UVA irradiation effect (P<0.05). The migration rates of the normal group and the UVA-irradiated NHDFs in the 5% CGF group had significantly increased migration rates (P<0.05), compared to the control medium group. The migration rates of the UVA-irradiated NHDFs in 5% CGF exceed those of the normal group. These results showed that 5% CGF could greatly promote cellular proliferation, migration, and SOD at the same time that the amounts of ROS were markedly decreased. CONCLUSIONS These experimental findings offer some important insights into CGF's capacity for scavenging ROS, improving SOD, and increasing migration rates in NHDFs irradiated by UVA.

Anticancer effect of YWHAZ silencing via inducing apoptosis and autophagy in gastric cancer cells

YWHAZ (14-3-3ζ) has been reported to be a prognostic marker for various tumors and play a crucial role in many oncogenic processes, including proliferation, migration and invasion. However, the functional role and mechanism of YWHAZ in gastric cancer (GC) are not in detail and still remain to be studied. In the present study, the endogenous expression of YWHAZ in gastric cancer cell line BGC-823 was silenced by YWHAZ-specific short hairpin RNA (shRNA). Our data showed that YWHAZ silencing resulted in cell cycle arrest in BGC-823 cells. Further, YWHAZ-silenced BGC-823 cells acquired increased apoptosis rate, which was confirmed by increased levels of cleaved caspase-3, cleaved PARP, and Bax, and decreased level of Bcl-2. Suppression of YWHAZ also promoted autophagy, confirming by the upregulation of LC3II /LC3I ratio, and downregulation of p62 level. Moreover, YWHAZ suppression inhibited the activation of PI3K/AKT/mTOR signaling pathway in BGC-823 cells. LY294002 (PI3K/AKT inhibitor, 200 nM) further promoted YWHAZ silencing-induced apoptosis and autophagy in BGC-823 cells, while insulin-like growth factor-1 (IGF-1; PI3K/AKT agonist, 10 ng/ml) had the opposite role. Finally, suppression of YWHAZ inhibited the growth of the xenograft tumor in vivo. This study provides extended evidence that YWHAZ can be a potential therapeutic target for GC.

Remission of systemic lupus erythematosus disease activity with regulatory cytokine interleukin (IL)-35 in Murphy Roths Large (MRL)/lpr mice

The immunological mechanisms mediated by regulatory cytokine interleukin (IL)-35 are unclear in systemic lupus erythematosus (SLE). We investigated the frequency of CD4(+) CD25(+) forkhead box protein 3 (FoxP3)(+) regulatory T (Treg ) and IL-10(+) regulatory B (Breg ) cells and related immunoregulatory mechanisms in a female Murphy Roths Large (MRL)/lpr mouse model of spontaneous lupus-like disease, with or without IL-35 treatment. A remission of histopathology characteristics of lupus flare and nephritis was observed in the MRL/lpr mice upon IL-35 treatment. Accordingly, IL-35 and IL-35 receptor subunits (gp130 and IL-12Rβ2) and cytokines of MRL/lpr and BALB/c mice (normal controls) were measured. The increased anti-inflammatory cytokines and decreased proinflammatory cytokines were possibly associated with the restoration of Treg and Breg frequency in MRL/lpr mice with IL-35 treatment, compared to phosphate-buffered saline (PBS) treatment. mRNA expressions of Treg -related FoxP3, IL-35 subunit (p35 and EBI3) and soluble IL-35 receptor subunit (gp130 and IL12Rβ2) in splenic cells were up-regulated significantly in IL-35-treated mice. Compared with the PBS treatment group, IL-35-treated MRL/lpr mice showed an up-regulation of Treg -related genes and the activation of IL-35-related intracellular Janus kinase/signal transducer and activator of transcription signal pathways, thereby indicating the immunoregulatory role of IL-35 in SLE. These in vivo findings may provide a biochemical basis for further investigation of the regulatory mechanisms of IL-35 for the treatment of autoimmune-mediated inflammation.

Amelioration of allergic airway inflammation in mice by regulatory IL-35 through dampening inflammatory dendritic cells

BACKGROUND

IL-35, a new member of the IL-12 family, is an inhibitory cytokine produced by regulatory T and B lymphocytes that play a suppressive role in the inflammatory diseases. This study focuses on the cellular mechanism regulating the anti-inflammatory activity of IL-35 in asthmatic mice.

METHODS

Ovalbumin-induced asthmatic and humanized asthmatic mice were adopted to evaluate the in vivo anti-inflammatory activities of IL-35. For monitoring the airway, Penh value (% baseline) was measured using a whole-body plethysmograph.

RESULTS

In this study using ovalbumin-induced asthmatic mice, we observed that intraperitoneal injection of IL-35 during the allergen sensitization stage was more efficient than administration in the challenge stage for the amelioration of airway hyper-responsiveness. This was reflected by the significantly reduced concentration of asthma-related Th2 cytokines IL-5 and IL-13, as well as eosinophil counts in bronchoalveolar lavage fluid (all P < 0.05). IL-35 also significantly attenuated the accumulation of migratory CD11b+CD103(-) dendritic cells (DC) in the mediastinal lymph node (mLN) and lung of mice (all P < 0.05). IL-35 markedly inhibited the ovalbumin-induced conversion of recruited monocytes into inflammatory DC, which were then substantially reduced in mLN to cause less T-cell proliferation (all P < 0.05). Further study using the humanized asthmatic murine model also indicated human IL-35 exhibited a regulatory impact on allergic asthma.

CONCLUSION

Our findings suggest that IL-35 can act as a crucial regulatory cytokine to inhibit the development of allergic airway inflammation via suppressing the formation of inflammatory DC at the inflammatory site and their accumulation in the draining lymph nodes.

[A qualitative research on the psychological experience of hospitalized patients with acute myocardial infarction]

OBJECTIVE

To observe the psychological experience of patients with acute myocardial infarction (AMI) during hospitalization.

METHODS

From November 2012 to February 2013, semi-structured interviews were conducted in 10 patients with AMI in the Cardiovascular Department of First Affiliated Hospital of Henan University of Science and Technology. Grounded theory approach was performed to analyze the collected data.

RESULTS

The 6 themes and 3 secondary themes during their hospitalization were: helplessness and dependence when AMI was diagnosed fear of immediate death induced by AMI, confusion on various problems such as operation time, excretory after PCI and limited knowledge details, the feel of safety after PCI, the fear of AMI, and the worry about overtreatment.

CONCLUSIONS

Hospitalized AMI patients have complicated psychological responses. Medical staff should provide targeted strategies and timely communication with AMI patients to reduce their psychological burden.

Aberrant expression of regulatory cytokine IL-35 in patients with systemic lupus erythematosus

Objective

This study characterizes an IL-35-mediated regulatory role in patients with systemic lupus erythematosus (SLE).

Methods

Plasma of SLE patients and healthy controls (HCs) was analyzed for the concentrations of IL-35 and soluble gp130 by using ELISA. mRNA expression of IL-35 subunit (p35 and EBI3) and its receptor (gp130 and IL-12Rβ2) in peripheral blood mononuclear cells (PBMCs) was assessed by RT-qPCR. Flow cytometry was performed to evaluate the number of CD4+CD25highCD127−Treg cells and the expression of IL-35 receptor on the CD4+ helper (Th) cells and CD19+ B cells. Plasma collected from SLE patients and HCs was assayed for cytokine and chemokine expression by Luminex multiplex assay.

Results

Plasma IL-35 and soluble gp130 levels positively correlated with each other and were significantly higher in patients with severe SLE compared with HCs. Significantly higher levels of inflammatory cytokines/chemokines CCL2, CXCL8, IL-6, interferon (IFN)-γ, IL-10 and IL-17A were observed in plasma of SLE patients than HCs. mRNA levels of IL-35 and its receptor were significantly positively correlated in PBMCs from SLE patients and their levels were higher in SLE than HCs. The increase significantly correlated with changes in SLE Disease Activity Index (SLEDAI) (all p < 0.05). In addition, the number of Treg cells in severe and moderate SLE patients were both significantly lower than HCs, where the ratio of CD4+CD25−effector T cell %/CD4+CD25highCD127−Treg % was found to be significantly higher in severe SLE patients. Furthermore, the expression of gp130 on CD4+ Th cells and percentage of Tregs were positively correlated with each other, and both were negatively correlated with SLEDAI.

Conclusion

Our findings indicate that high level of plasma IL-35 in active SLE patients expressed with low level of IL-35 receptor (gp130) on CD4+ Th cells. These data raise the possibility that the level of IL-35 expression in SLE patients is not sufficient to induce the production of CD4+CD25highCD127−Tregs, and subsequently suppress the release of inflammatory cytokines and chemokines upon inflammation.

Structure and mechanical properties of naturally occurring lightweight foam-filled cylinder--the peacock's tail coverts shaft and its components

Feather shaft, which is primarily featured by a cylinder filled with foam, possesses a unique combination of mechanical robustness and flexibility with a low density through natural evolution and selection. Here the hierarchical structures of peacock's tail coverts shaft and its components are systematically characterized from millimeter to nanometer length scales. The variations in constituent and geometry along the length are examined. The mechanical properties under both dry and wet conditions are investigated. The deformation and failure behaviors and involved strengthening, stiffening and toughening mechanisms are analyzed qualitatively and quantitatively and correlated to the structures. It is revealed that the properties of feather shaft and its components have been optimized through various structural adaptations. Synergetic strengthening and stiffening effects can be achieved in overall rachis owing to increased failure resistance. This study is expected to aid in deeper understandings on the ingenious structure-property design strategies developed by nature, and accordingly, provide useful inspiration for the development of high-performance synthetic foams and foam-filled materials.

Characteristics of anaphylaxis-inducing IgG immune complexes triggering murine passive systemic anaphylaxis

BACKGROUND

With the broad and increasing application of therapeutic monoclonal antibodies (mAbs) in clinical settings, IgG-induced allergic reactions, including passive systemic anaphylaxis (PSA), have attracted significant attention. However, it is not clear which types of IgG mAb-antigen complexes or IgG aggregates formed by antigen binding can trigger PSA, as not all immune complexes (ICs) are capable of triggering PSA. Here, we characterise mAb-antigen complexes capable of inducing murine PSA to evaluate and predict which ICs are able to induce PSA.

METHODS

Thirty-six combinatory reactions with eight antigens and 27 corresponding mAbs were used to trigger PSA, which was defined by rectal temperature. Sandwich ELISA, passive cutaneous anaphylaxis (PCA) induction and flow cytometry analysis of CD16/32 (FcγRIII/II) expression were used to characterise the ICs. The dynamic concentrations of antigen in the peripheral blood were measured by ELISA.

RESULTS

Only 14 of the 36 ICs could trigger PSA and thus be termed anaphylaxis-inducing immune complexes (Ai-ICs). The Ai-ICs could be characterised by constructing sandwich ELISA, inducing PCA and down-regulating CD16/32 (FcγRIII/II) expression on blood neutrophils in vitro and in vivo. Additionally, the occurrence and severity of PSA was found to be associated with the instantaneous concentration of antigen in the peripheral blood in the presence of antibody.

CONCLUSIONS

Only Ai-ICs, not all ICs, could trigger IgG-mediated PSA, which could be characterised by the above simple methods. The occurrence and severity of PSA was associated with the instantaneous concentration of antigen in the peripheral blood in the presence of antibody.

[Effect of kintop on gastrointestinal movement and its significance]

OBJECTIVE

To study the effect of obesity-reducing drug Kintop on gastrointestinal movement in rats.

METHODS

Eighteen Wistar rats were divided into high dose (200 mg/100 g) Kintop group, low dose (125 mg/100 g) Kintop group, and control group. After anesthesia, stomach emptying time was directly observed using methylene blue as indicator. The frequency and amplitude of intestinal movement, and movement speed of intestinal content were detected. The serum tumor necrosis factora (TNF alpha) level was measured by ELISA.

RESULTS

After administration of Kintop, the stomach emptying time was prolonged markedly, movement speed of intestinal content accelerated, time of dejection increased, the intestinal movement frequency and amplitude increased. There was a negative correlation between intestinal movement frequency and serum TNF alpha level (r = -0.91, P < 0.05).

CONCLUSIONS

Kintop could significantly prolong the stomach emptying time, accelerate intestinal movement. These effects are correlated with not only the increased time of dejection but also the lowered serum TNF alpha level.

Fast frequency-sweep analysis of RF coils for MRI

A fast frequency-sweep technique is developed for the analysis of radio-frequency coils for magnetic resonance imaging. This technique applies the method of asymptotic waveform evaluation to the moment method solution of the integral equation for the original physical problem. Numerical examples show that the proposed technique can speed up the analysis by more than an order of magnitude.

Relation between antibodies to BP180 and gender in bullous pemphigoid

Bullous pemphigoid is associated with antibodies to 2 basement membrane zone antigens (BP230 and BP180). In some patients antibodies develop to one of these antigens, whereas in others antibodies develop to both. Although the factors behind this are unknown, our study indicates that male gender is one factor.

Vitiligo antibodies are not directed to tyrosinase

BACKGROUND

Patients with vitiligo have a markedly increased incidence of antibodies to melanocytes, referred to as vitiligo antibodies. Antibodies to tyrosinase have been reported in some patients with vitiligo, suggesting that vitiligo antibodies may be directed to this enzyme. However, there is considerable controversy as to the frequency with which these antibodies occur, and, hence, about their relevance to the pathogenesis of vitiligo. The frequency with which antityrosinase antibodies occur in vitiligo is critical to evaluate their potential role in the pathogenesis of this disease.

OBJECTIVE

To examine the prevalence of antibodies to tyrosinase in a large group of patients with vitiligo.

DESIGN

We examined the incidence of antibodies to enzymatically and immunologically active tyrosinase in patients with and without vitiligo.

SETTING

Outpatient clinic in referral center.

PATIENTS

The study was conducted on serum samples obtained from 54 patients with active (n = 40) and inactive (n = 14) uncomplicated vitiligo and from 52 age- and sex-matched individuals without vitiligo.

MAIN OUTCOME MEASURE

Presence in the serum of antibodies to enzymatically and/or immunologically active tyrosinase.

RESULTS

By immunoblotting, 20 patients (50%) with active vitiligo, 9 of those (64.3%) with inactive vitiligo, and 29 control individuals (55.8%) had antibodies to an antigen that comigrated with tyrosinase. However, by immunoprecipitation DOPA stain and by sandwich enzyme-linked immunosorbent assay, none of the vitiligo or control individuals had antibodies to tyrosinase, even though both assays easily detected control antityrosinase antibodies.

CONCLUSION

These results indicate that while antibodies to an antigen(s) that comigrates with tyrosinase are common in patients with or without vitiligo, vitiligo antibodies are not directed to tyrosinase.

Disposition and pharmacokinetics of phenethyl isothiocyanate and 6-phenylhexyl isothiocyanate in F344 rats

Naturally occurring phenethyl isothiocyanate (PEITC) and its synthetic homolog 6-phenylhexyl isothiocyanate (PHITC) are both effective inhibitors of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone-induced lung tumor development in A/J mice and F344 rats. To help explain why PHITC is considerably more efficacious than PEITC in chemopreventive potency, comparative disposition and pharmacokinetics data for male F344 rats were obtained after a single gavage dose of 50 micromol/kg (3.71 microCi/micromol) [14C]PEITC or 50 micromol/kg (6.59 microCi/micromol) [14C]PHITC in corn oil. After [14C]PEITC dosing, whole blood 14C peaked at 2.9 h, with an elimination half-life (T1/2e) of 21.7 h; blood 14C from [14C]PHITC-treated rats peaked at 8.9 h, with an T1/2e of 20.5 h. In lungs, the target organ, the T1/2e for [14C]PHITC and its labeled metabolites were more than twice that for [14C]PEITC and its labeled metabolites. The effective dose (area under the concentration-time curve) for 14C from PHITC was greater than 2.5 times the area under the concentration-time curve of 14C from PEITC in liver, lungs, and several other tissues. During 48 h, approximately 16.5% of the administered dose of [14C]PHITC was expired as [14C]CO2, more than 100 times the [14C]CO2 expired by rats treated with [14C]PEITC. In rats given [14C]PEITC, 88.7 +/- 2.2% and 9.9 +/- 1.9% of the dose appeared in the urine and feces, respectively, during 48 h; however, rats given [14C]PHITC excreted 7.2 +/- 0.8% of the dose of 14C in urine and 47.4 +/- 14.0% in the feces. Higher effective doses of PHITC in the lungs and other organs may be the basis, in part, for its greater potency as a chemopreventive agent.

Urinary total isothiocyanate (ITC) in a population-based sample of middle-aged and older Chinese in Singapore: relationship with dietary total ITC and glutathione S-transferase M1/T1/P1 genotypes

Isothiocyanates (ITCs), degradation products of glucosinolates (which occur naturally in a variety of cruciferous vegetables), have been shown to exhibit chemopreventive activity. These compounds are metabolized in vivo to form the corresponding dithiocarbamates, which are the major urinary metabolites of ITCs, by a pathway involving the glutathione S-transferase (GST) class of enzymes. Using a newly developed assay that measures total ITC (primarily ITC conjugates) in urine, we examined the relationships between cruciferous vegetable intake (obtained from a food frequency/portion size questionnaire administered in person); dietary total ITC level; GSTM1, GSTT1, and GSTP1 genotypes; and levels of total ITC in spot urine samples collected from 246 Singapore Chinese (111 men and 135 women), ages 45-74 years, who are participants of the Singapore Cohort Study on diet and cancer. Consumption level of cruciferous vegetables was high in study subjects (mean consumption = 345 times per year, mean daily intake = 40.6 g), which was >3 times the comparable level of intake in the United States. Mean daily intake of total ITC among study subjects was 9.1 micromol, and there was a 2.5-fold difference between the 25th and 75th percentile values. Seventy-three % of study subjects tested positive for ITC in urine, and there was a 4-fold difference between the 25th and 75th percentile values among the positive subjects. There was a highly significant positive association between dietary intake and urinary excretion levels of total ITC (two-sided P = 0.0003) that was stronger than the association between overall cruciferous vegetable intake and urinary ITC level, which also was statistically significant (P = 0.0004). There was no difference in urinary ITC levels between GSTM1-null and GSTM1-positive study subjects (P = 0.61) or between subjects with differing GSTP1 genotypes (P = 0.77), but urinary excretion of ITC was significantly higher among GSTT1-positive subjects, relative to GSTT1-null subjects (P = 0.006). The strength of the association between GSTT1 genotype and urinary total ITC level was highly dependent on the level of cruciferous vegetable consumption (or dietary ITC level) in study subjects. Among subjects in the lowest tertile of cruciferous vegetable intake, there was little evidence of an association between GSTT1 genotype and urinary total ITC level (P = 0.67). In contrast, there was a strong and statistically significant association between GSTT1 genotype and urinary total ITC among subjects in the highest tertile of cruciferous vegetable intake (P = 0.02), whereas those in the middle tertile of cruciferous vegetable consumption exhibited an association of intermediate strength (P = 0.04). These results suggest the presence of GSTT1 inducers in cruciferous vegetables.

Antibodies to desmoplakin in a patient with pemphigus foliaceous

BACKGROUND

Antibodies to desmoplakins have been associated with paraneoplastic pemphigus. Here, we report a case of non-neoplastic pemphigus foliaceous with antibodies to desmoplakins.

OBSERVATION

A 61-year-old woman with pemphigus foliaceous by clinical, histological and immunofluorescent criteria was found to have circulating antibodies to 250 and 215 kDa antigens identified as desmoplakin I and II by immunoblotting and immunoprecipitation. The patient had no evidence of cancer during a follow-up period of 3 years.

CONCLUSION

Although antibodies to desmoplakin I and II have previously been associated with paraneoplastic pemphigus, their occasional finding in erythema multiforme and bullous pemphigoid indicates that they can also occur in non-neoplastic pemphigus.

Chemopreventive potential of thiol conjugates of isothiocyanates for lung cancer and a urinary biomarker of dietary isothiocyanates

Natural and synthetic isothiocyanates (ITCs) are versatile chemopreventive agents in many animal systems. We have shown that phenethyl ITC (PEITC) and 6-phenylhexyl ITC (PHITC) are potent inhibitors against lung tumorigenesis induced by tobacco nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) in both mouse and rat. The mechanism by which these ITCs inhibited lung tumorigenesis is attributed to their ability to decrease cytochrome P450 (P450) enzyme activities involved in the activation of NNK. Recently, we have found that thiol conjugates of ITCs inhibit P450 enzymes and are effective inhibitors of lung tumorigenesis. This is significant because conjugation with cellular thiols is the major route of ITC metabolism via the mercapturic acid pathway in rodents and humans. The thiol conjugates are less pungent and potentially less toxic, and they are more soluble and chemically less reactive than ITCs. These properties raise the prospect of substituting thiol conjugates for ITCs as chemopreventive agents. Furthermore, although ample rodent studies have established that ITCs inhibit tumorigenesis, the protective role of dietary ITCs against human cancers has not yet been established. As a prerequisite for such human studies, we have developed an HPLC-based assay, based on the condensation reaction of ITCs or conjugates with 1,2-benzenedithiol, for measuring a cyclocondensation product in human urine as an uptake biomarker of total ITCs. This assay was validated using urine samples from subjects who had ingested a known amount of watercress or mustard in a controlled diet. The assay is convenient and rapid, showing promise for analyzing urine samples obtained from population-based studies. Results from two such studies are presented to illustrate the potential application of this biomarker in epidemiologic studies.

Chemopreventive potential of fumaric acid, N-acetylcysteine, N-(4-hydroxyphenyl) retinamide and beta-carotene for tobacco-nitrosamine-induced lung tumors in A/J mice

Four agents, fumaric acid (FA), N-acetylcysteine (NAC), N-(4-hydroxyphenyl) retinamide (4-HPR) and beta-carotene (beta-CT), were evaluated for potential chemopreventive activity using the tobacco-specific carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK)-induced lung tumor model in female A/J mice. The agents were evaluated in both 16-week and 52-week bioassays at two dose levels corresponding to 0.8 maximum tolerated dose (MTD) and 0.4 MTD administered throughout the bioassay either in the diet (FA, 160 and 80 mmol/kg diet; NAC, 160 and 80 mmol/kg diet; 4-HPR, 4 and 2 mmol/kg diet) or by subcutaneous injection twice a week (beta-CT, 32 and 16 mg/kg b.w.). Mice were treated with a single i.p. dose of 10 micromol NNK in saline 1 week after administration of test agent. Lung adenomas were evaluated in the 16-week bioassay, whereas both adenomas and adenocarcinomas of the lung were determined in the 52-week bioassay. Both bioassays showed that all four agents did not significantly inhibit the total tumor incidence and multiplicity of the lung. However, the incidence of adenocarcinomas was reduced (P < 0.01) at 52 weeks in NNK groups given either 0.8 MTD NAC or 0.8 MTD beta-CT compared with the NNK control group. The decreases in adenocarcinomas were accompanied by corresponding increases in adenomas in these treatment groups. Thus, this study showed that FA, NAC, 4-HPR and beta-CT did not inhibit the total tumor formation, however, at the higher doses both NAC and beta-CT significantly retarded the malignant progression in the lung of NNK-treated A/J mice.

A urinary biomarker for uptake of dietary isothiocyanates in humans

Isothiocyanates (ITCs) are a family of biologically active compounds that are distributed widely in cruciferous vegetables. Although studies in rodents have shown that these compounds are effective and versatile inhibitors of tumorigenesis, the role of dietary ITCs in the protection against human cancers remains to be established. A prerequisite of human studies is to develop an uptake biomarker for dietary ITCs. In this study, we describe a rapid high-performance liquid chromatography-based assay to measure the total ITC level in human urine. This assay is based on a previously described reaction of ITCs or their thiol conjugates with 1,2-benzenedithiol to yield a cyclocondensation product, 1,3-benzodithiole-2-thione, which then can be quantified by reverse phase high-performance liquid chromatography with UV detection. This new assay was validated by analyzing urine samples from 14 subjects who had consumed a known amount of watercress or brown mustard in a controlled experiment. The N-acetylcysteine conjugates of phenethyl ITC and allyl ITC from watercress and brown mustard, respectively, were quantified and compared with the results obtained from the current assay. Results of the two methods were highly correlated (r = 0.978), indicating the specificity of this new assay for dietary ITCs. The feasibility of this assay for population-based studies was examined using stored urine samples collected from nine participants of a prospective cohort study in Shanghai, China, who indicated that they were daily consumers of dark green vegetables. There was a 10-fold variation in urinary ITC contents among these samples, ranging from 0.7 to 7.0 micromol/g creatinine. These results show the potential use of this uptake biomarker in epidemiological studies to identify the role of dietary ITCs in modifying cancer risks in humans.

Chemopreventive activity of thiol conjugates of isothiocyanates for lung tumorigenesis

A series of L-cysteine (L-Cys), glutathione (GSH), and N-acetyl-L-cysteine (NAC) conjugates of phenethyl (PEITC), benzyl (BITC), and 6-phenylhexyl isothiocyanate (PHITC) were studied for their inhibitory activity toward metabolic activation of the tobacco-specific nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) in mouse lung microsomes. Selected compounds, PEITC, PEITC-GSH, PEITC-NAC and PHITC-NAC, were also assayed for the potential chemopreventive activity toward NNK-induced lung tumorigenesis in A/J mice. Results showed that PEITC and its conjugates inhibited NNK metabolism with decreasing potency: PEITC < PEITC-GSH > PEITC-Cys > PEITC-NAC. PHITC and its GSH and NAC conjugates exhibited nearly 10 times higher inhibitory activity toward NNK metabolism than the PEITC counterparts. In the tumor bioassay, as expected, the conjugates exhibited inhibitory activity against lung tumorigenesis induced by NNK. PEITC-GSH was not inhibitory at 4 micromol/mouse, but it inhibited approximately 32% of lung tumor multiplicity at 8 micromol/mouse. PEITC-NAC at 5 and 20 micromol/mouse both inhibited approximately 30% tumor multiplicity. Among all the conjugates examined, PHITC-NAC was the most potent. At a 5-micromol dose, it completely inhibited tumor multiplicity and incidence to the background level observed in the control group. These results revealed that the structure-activity relationships of the conjugates are similar to those found with their parent isothiocyanates (ITCs), i.e., the potency increased with the increasing alkyl chain length from two to six carbons in arylalkyl ITCs, suggesting that a common active species is involved. The inhibitory activity of ITC conjugates and the expected low toxicity make thiol conjugates of ITC a promising new series of chemopreventive agents.

Sensitivity of indirect immunofluorescence, substrate specificity, and immunoblotting in the diagnosis of pemphigus

BACKGROUND

Several assays are available to detect pemphigus antibodies. The most commonly used are indirect immunofluorescence (IIF) and immunoblotting (IB).

OBJECTIVE

Our purpose was to compare the sensitivity of these assays in detecting pemphigus antibodies.

METHODS

Fifty-two sera from 41 patients with pemphigus vulgaris (PV) and 22 sera from 18 patients with pemphigus foliaceus (PF) were tested concurrently for the presence of pemphigus antibodies. The IIF studies were conducted with two different substrates: monkey and guinea pig esophagus.

RESULTS

Pemphigus antibodies were detected with equal sensitivity by IIF in patients with PV and PF (i.e., positive in 87% and 86% of sera, respectively). By contrast, IB assay was much less sensitive in PF than in PV (i.e., positive in 45% vs 83% of sera, respectively). The antibodies in PV generally reacted more strongly against monkey esophagus, whereas those in PF reacted more strongly against guinea pig esophagus. All patients with intercellular antibodies that reacted more strongly against monkey than guinea pig esophagus had PV, whereas all those with intercellular antibodies that reacted more strongly against guinea pig than monkey esophagus had PF.

CONCLUSION

IIF is a more sensitive assay than IB for detecting antibodies associated with PF. The substrate specificity of the antibodies provides a simple means to distinguish between PV and PF.

Inhibition of rat liver cytochrome P450 isozymes by isothiocyanates and their conjugates: a structure-activity relationship study

A series of arylalkyl and alkyl isothiocyanates, and their glutathione, cysteine, and N-acetylcysteine conjugates were used to study their inhibitory activity toward the dealkylation of ethoxyresorufin (EROD), pentoxyresorufin (PROD), and methoxyresorufin (MROD) in liver microsomes obtained from the 3-methylcholanthrene or phenobarbital-treated rats. These reactions are predominantly mediated by cytochrome P450 (P450) isozymes 1A1 and 1A2, 2B1 and 1A2, respectively. All isothiocyanates inhibited PROD more readily than EROD. Increases in the alkyl chain length of arylalkyl isothiocyanates to C6 resulted in an increased inhibitory potency in these assays; at longer alkyl chain lengths (C8-C10) the inhibitory potency declined. The IC50s for phenethyl isothiocyanate (PEITC) were 47, 46 and 1.8 microM for EROD, MROD and PROD, respectively. Substitution of an additional phenyl group on PEITC also increased the inhibitory potency; the IC50s for 1,2-diphenylethyl isothiocyanate (1,2-DPEITC) and 2,2-diphenylethyl isothiocyanate (2,2-DPEITC) were 0.9 and 0.26 microM for EROD, and 0.045 and 0.13 microM for PROD, respectively. The relative inhibitory potency of PEITC and its conjugates was N-acetylcysteine-PEITC (PEITC-NAC) < glutathione-PEITC (PEITC-GSH) < cysteine-PEITC (PEITC-CYS) < PEITC. The observations that the parent isothiocyanates were more potent inhibitors than the conjugates suggest that dissociation of the conjugate is required for activity. Naturally occurring alkyl isothiocyanates, sulforaphane (SFO) and allyl isothiocyanate (AITC), were very weak inhibitors in the assays. These results suggest the potential of isothiocyanates as structural probes for studying P450 isozymes. In addition, the inhibitory activity of isothiocyanates for PROD correlated with the previously demonstrated tumor inhibitory potency in (4-methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) induced A/J mouse lung tumor bioassays, which supports earlier findings that P450 2B1 is one of the major isozymes involved in NNK activation and that inhibition of this isozyme is an important mechanism for the chemopreventive activity of isothiocyanates.

Inhibition of N-nitrosodimethylamine demethylase in rat and human liver microsomes by isothiocyanates and their glutathione, L-cysteine, and N-acetyl-L-cysteine conjugates

Natural and synthetic isothiocyanates and their conjugates were examined for their inhibitory effects toward rat and human liver microsomal N-dimethylnitrosoamine demethylase (NDMAd) activity using a radiometric NDMAd assay. Substrate concentrations of 30 and 60 microM were used to probe the activity of cytochrome P4502E1 isozyme through the alpha-hydroxylation of NDMA. It was found that alkyl isothiocyanates such as sulforaphane and allyl isothiocyanate displayed very weak inhibition, whereas the arylalkyl isothiocyanates such as benzyl and phenethyl isothiocyanate showed significant inhibition toward rat liver NDMAd activity with IC50 values of 9.0 and 8.3 microM, respectively. More interestingly, glutathione conjugates of benzyl, phenethyl, and 6-phenylhexyl isothiocyanates all inhibited NDMAd at the comparable concentrations. In the phenethyl isothiocyanate conjugates series, there exist marked differences in their inhibitory activity; i.e., its conjugates with L-cysteine (IC50 = 4.3 microM) and with glutathione (IC50 = 4.0 microM) are more potent than its conjugate of N-acetylcysteine (IC50 = 24.0 microM). The same trend was also observed for the human liver microsomal NDMAd activity. The half-lives of these conjugates were determined in the presence of other free thiols from L-cysteine or glutathione using an HPLC system. It was shown that isothiocyanates are released from their conjugates and react with the free thiols present in the solution. The longer half-life of N-acetylcysteine conjugate of phenethyl isothiocyanate as compared to the other conjugates is consistent with its lower inhibitory activity. The inhibition of NDMAd, and therefore cytochrome P4502E1, by isothiocyanate conjugates is most likely due to the action of the free isothiocyanates released from the conjugates. Since cytochrome P4502E1 and other isozymes play important roles in the activation of the tobacco-specific nitrosoamines, these results provide a basis for investigating the potential of isothiocyanate conjugates as chemopreventive agents.

The essential role of the functional group in alkyl isothiocyanates for inhibition of tobacco nitrosamine-induced lung tumorigenesis

The importance of the isothiocyanate group in alkyl isothiocyanate for inhibition of tobacco-specific nitrosamine 4-(methylnitrosamino)-1-(3- pyridyl)-1-butanone (NNK)-induce lung tumorigenesis was examined in A/J mice. Our previous structure-activity relationship study of isothiocyanates showed that 1-dodecyl isothiocyanate [CH3(CH2)11NCS], a simple alkyl isothiocyanate, is a potent inhibitor of NNK-induced lung tumorigenesis. It was chosen for this study due to its structural features and potency. A single dose of 1-dodecyl isothiocyanate given by gavage at 1 micromol/mouse 2 h prior to NNK administration completely inhibited lung tumorigenesis, while removal of the isothiocyanate group or replacing it with a hydroxyl group abolished the inhibitory activity. These results demonstrate that the isothiocyanate functional group is critical for the inhibitory activity of isothiocyanates in NNK-induced lung tumorigenesis. To gain more insights into the relationship of in vivo inhibition of tumorigenesis with the cytochrome P-450 enzyme inhibitory activity, the effects of these compounds on metabolism of NNK in mouse lung microsomes were studied. 1-Dodecyl isothiocyanate inhibited all three known oxidative pathways of NNK metabolism, with a stronger inhibitory activity toward NNK N-oxidation (IC50 430 nM) and keto alcohol formation (IC50 500 nM) than keto aldehyde formation (IC50 13,000 nM). 1-Dodecanol had a similar selectivity in inhibition of these metabolic pathways, but was less potent than 1-dodecyl isothiocyanate. Dodecane showed little or no inhibitory activity in the same concentration range. These results indicate that the isothiocyanate group of 1-dodecyl isothiocyanate is important for inhibition of NNK-induced lung tumorigenesis and also for effective inhibition of cytochrome P-450 enzymes involved in NNK oxidation.

Chemopreventive efficacy of arylalkyl isothiocyanates and N-acetylcysteine for lung tumorigenesis in Fischer rats

The purpose of this study is to evaluate the efficacy of three promising sulfur-containing compounds, 6-phenylhexyl isothiocyanate (PHITC), phenethyl isothiocyanate (PEITC), and N-acetylcysteine (NAC), as chemopreventive agents in a long-term bioassay for lung tumorigenesis in F344 rats. PEITC occurs as a constituent of certain cruciferous vegetables, PHITC is a synthetic homologue, and NAC is an endogenous substance. Male F344 rats were treated with the tobacco-specific nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) by s.c. injection at a dose of 1.5 mg/kg body weight three times weekly for 20 weeks. This dose regimen induced a 67% tumor incidence in the lung, a major target organ of NNK. PHITC or PEITC administered in the diet for 22 weeks, a period covering from 1 week before to 1 week after the NNK treatment, exhibited significant inhibition of lung tumorigenesis induced by NNK. The lung tumor incidences in the NNK-treated groups, fed a diet containing 4 mmol/kg (876 ppm) or 2 mmol/kg (438 ppm) PHITC, were 24 and 19% and were 9 and 17% in groups fed PEITC at concentrations of 8 mmol/kg (1304 ppm) or 4 mmol/kg (652 ppm), respectively. In contrast to isothiocyanates, NAC given in the diet at 80 mmol/kg (13056 ppm) or 40 mmol/kg (6528 ppm) exerted no inhibitory effects on the NNK-induced lung tumorigenesis. At the dose studied, NNK did not induce liver and pancreatic tumors in the treated animals, but a significant increase of nasal cavity tumor incidence was observed in the NNK-treated group. However, none of the test compounds showed any effect on the tumorigenesis in this tissue. This study demonstrated that PHITC and PEITC were potent chemopreventive agents for the NNK-induced lung tumorigenesis in F344 rats, whereas NAC was not active at all. These results support further evaluation of these compounds in chemoprevention studies.

Conformational analysis of beta-methyl-para-nitrophenylalanine stereoisomers of cyclo[D-Pen2, D-Pen5]enkephalin by NMR spectroscopy and conformational energy calculations

Solution conformations of beta-methyl-para-nitrophenylalanine4 analogues of the potent delta-opioid peptide cyclo[D-Pen2, D-Pen5]enkephalin (DPDPE) were studied by combined use of nmr and conformational energy calculations. Nuclear Overhauser effect connectivities and 3JHNC alpha H coupling constants measured for the (2S, 3S)-, (2S, 3R)-, and (2R, 3R)-stereoisomers of [beta-Me-p-NO2Phe4]DPDPE in DMSO were compared with low energy conformers obtained by energy minimization in the Empirical Conformational Energy Program for Peptides (ECEPP/2) force field. The conformers that satisfied all available nmr data were selected as probable solution conformations of these peptides. Side-chain rotamer populations, established using homonuclear (3JH alpha H beta) and heteronuclear (3JH alpha C gamma) coupling constants and 13C chemical shifts, show that the beta-methyl substituent eliminates one of the three staggered rotamers of the torsion angle chi 1 for each stereoisomer of the beta-Me-p-NO2Phe4. Similar solution conformations were suggested for the L-Phe4-containing (2S, 3S)- and (2S, 3R)-stereoisomers. Despite some local differences, solution conformations of L- and D-Phe4-containing analogues have a common shape of the peptide backbone and allow similar orientations of the main delta-opioid pharmacophores. This type of structure differs from several models of the solution conformations of DPDPE, and from the model of biologically active conformations of DPDPE suggested earlier. The latter model is allowed for the potent (2S, 3S)- and (2S, 3R)-stereoisomers of [beta-Me-p-NO2Phe4]DPDPE, but it is forbidden for the less active (2R, 3R)- and (2R, 3S)-stereoisomers. It was concluded that the biologically active stereoisomers of [beta-Me-p-NO2Phe4]DPDPE in the delta-receptor-bound state may assume a conformation different from their favorable conformations in DMSO.

Ipomeanol analogs as chemopreventive agents: effect on the in vitro metabolism of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK)

4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) is a tobacco-specific, powerful, organospecific lung carcinogen. 4-Ipomeanol (IPO) is an investigational chemotherapeutic drug with specific toxicity towards the lung. We hypothesized that non-toxic analogs of IPO could be competitive inhibitors of the metabolic activation of NNK. We had shown previously that 4-hydroxy-1-phenyl-1-pentanone (HPP) and 7-hydroxy-1-phenyl-1-octanone (4-HPO) are effectively inhibiting the lung tumor activity of NNK in A/J mice. In these extended studies we have synthesized 11 new analogs of HPP and tested them for their in vitro activities as inhibitors of the metabolism of NNK. The present study demonstrated that the lipophilicity in the molecule is playing an important role for the inhibition of NNK metabolism with pulmonary and hepatic microsomes of A/J mice.

Identification and quantification of the N-acetylcysteine conjugate of allyl isothiocyanate in human urine after ingestion of mustard

Allyl isothiocyanate (AITC) is a constituent of cruciferous vegetables. It occurs widely in the human diet as a natural ingredient or food additive. AITC possesses numerous biochemical and physiological activities. It is cytotoxic and tumorigenic at high doses and also is a modulator of enzymes involved in metabolism of xenobiotics, including carcinogens. It is plausible that the wide consumption of dietary AITC may have profound effects on human health. To facilitate investigations of the effects of dietary AITC in humans, a method of measuring its uptake is needed. In this study, a urinary marker was developed for quantifying AITC uptake in humans. Four adult volunteers were asked to eat a meal containing brown mustard as the source of AITC. The 48-h urine samples were collected from these individuals and analyzed by reverse phase high performance liquid chromatography. A major urinary metabolite was found, which was identified as N-acetyl-S-(N-allylthiocarbamoyl)-L-cysteine, the N-acetylcysteine conjugate of AITC, by comparing its retention time and UV, nuclear magnetic resonance, and mass spectra with those of the synthetic standard. After ingestion of mustard, the AITC conjugate was detected in urine collected from 0 to 12 h. No conjugate was found in urine samples collected after 12 h. The major portion of this metabolite was excreted within 8 h. The average total excretion of AITC conjugate was 5.4 +/- 1.7 (SD) mg after consumption of 10 g of mustard and 12.8 +/- 2.0 mg when 20 g of mustard was consumed. Thus, a dose-dependent excretion of this metabolite was demonstrated.(ABSTRACT TRUNCATED AT 250 WORDS)

Structure-activity relationships of isothiocyanates as mechanism-based inhibitors of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone-induced lung tumorigenesis in A/J mice

A structure-activity relationship study was carried out to identify structural features in arylalkyl and alkyl isothiocyanates that are associated with the inhibitory potency of these compounds against lung tumorigenesis induced in A/J mice by the tobacco-specific nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK). These features include the alkyl chain length, phenyl substitution, and secondary isothiocyanates. The naturally occurring allyl isothiocyanate, phenethyl isothiocyanate, and the synthetic analogues such as 6-phenylhexyl isothiocyanate, 8-phenyloctyl isothiocyanate, 10-phenyldecyl isothiocyanate, 1,2-diphenylethyl isothiocyanate, 2,2-diphenylethyl isothiocyanate, and alkyl isothiocyanates (with 1-hexyl, 2-hexyl, and 1-dodecyl as alkyl moieties) were assayed in mice for their tumor inhibitory potential. The isothiocyanates were given in corn oil by gavage at doses of either 0.04, 0.1, and 0.2 mumol or 1 and 5 mumol 2 h prior to a single i.p. injection of 10 mumol NNK. Mice were sacrificed 16 weeks later and lung adenomas were counted. At 0.2 mumol, 8-phenyloctyl isothiocyanate and 10-phenyldecyl isothiocyanate were stronger inhibitors than the previously tested 6-phenylhexyl isothiocyanate, but the difference in potency was not obvious at the lower doses. At both 1 and 5 mumol, allyl isothiocyanate was inactive, while the other five synthetic isothiocyanates were considerably more potent than phenethyl isothiocyanate. In the alkyl isothiocyanate series, 2-hexyl isothiocyanate was more potent than 1-hexyl isothiocyanate, while 1-dodecyl isothiocyanate was the most potent at 1 mumol, reducing tumor multiplicity in the group treated with NNK alone from 11.1 to the background level. Also, 1,2-diphenylethyl isothiocyanate appeared to be a stronger inhibitor than 2,2-diphenylethyl isothiocyanate. In this study we have shown that the phenyl moiety is not essential for the inhibitory activity since alkyl isothiocyanates exhibit strong inhibitory effects against lung tumorigenesis. We have also shown that secondary isothiocyanates possess a higher potency than their structural isomers bearing a primary isothiocyanate. From results of this study and of seven previously studied isothiocyanates, we conclude that the observed inhibitory potency of isothiocyanates in the A/J mouse lung tumor model is correlated with their partition coefficients (log P) and the pseudo first order rate constants for the reaction of isothiocyanates toward glutathione (kobs). These results reveal that both high lipophilicity and low reactivity of isothiocyanates are important for inhibitory activity toward NNK-induced lung tumorigenesis. These observations provide a structural basis for the discovery of more effective chemopreventive agents.