POS0845 ASSESSING FRAILTY IN SYSTEMIC SCLEROSIS: A CROSS-SECTIONAL STUDY COMPARING FRAIL AND EDMONTON FRAILTY SCALES WITH PHYSICAL FRAILTY PHENOTYPE

Background

Systemic sclerosis (SSc) is a chronic disease characterized by autoimmunity, vasculopathy and fibrosis. During the disease course, patients with SSc are prone to accumulate multiple organ damage, increasing their vulnerability to adverse outcomes in comparison with individuals of the same age: a phenomenon called frailty. One of the most used definitions of frailty is the physical frailty phenotype (PFP) by Fried, et al. The PFP consists of 5 components: unintentional weight loss, exhaustion, muscle weakness, slow walking speed, and low physical activity. There is scarce data about frailty in patients with SSc.

Objectives

To study the prevalence and clinical aspects of PFP in a sample of patients with SSc. Also, we aim to investigate the diagnostic accuracy of the Fatigue, Resistance, Ambulation, Illness and Loss of weight (FRAIL) scale and the Edmonton frailty scale (EFS) using the PFP as the reference standard.

Methods

Cross-sectional study, including patients with SSc according to the 2013 ACR-EULAR classification criteria or the criteria suggested by Le Roy and Medsger for early disease. PFP assessment was according to the original definition, except for physical activity domain, assessed with the International Physical Activity Questionnaire (IPAQ). Patients were classified according to Fried’s criteria in robust (0), pre-frail (1-2), and frail (≥3). FRAIL scale and EFS were also applied to the same individuals. The FRAIL score ranges from 0 to 5 and patients were classified as robust (0), pre-frail (1-2), or frail (≥3). The EFS score ranges from 0–17 and categorizes patients as not frail (0–4), vulnerable (5–6), mild frailty (7–8), moderate frailty (9–10), and severe frailty (≥11). For the diagnostic assessment of FRAIL scale and EFS, we estimated the area under the receiver operating characteristic curve (AUC), considering PFP as the reference standard and dichotomizing the results in frail vs. non-frail.

Results

Between March and December 2019, 82 SSc patients were consecutively included. The mean age and disease duration were 60.4 (±10.6) and 13.4 (±8.2) years, respectively; 91.5% were women, and 19.5% with diffuse cutaneous SSc. The PFP distribution was: 8 (9.8%) robust, 47 (57.3%) pre-frail and 27 (32.9%) frail patients. The PFP domains´ frequencies were: low physical activity in 57 (69.5%), muscle weakness in 41 (50%), exhaustion in 34 (41.5%), unintentional weight loss in 15 (18.3%) and slow walking speed in 8 (9.8%) patients. Using the FRAIL scale, 44 (53.7%) patients were considered pre-frail and 25 (30.5%) frail. According to the EFS, 26 patients (31.7%) were classified as vulnerable and 12 (14.6%) as frail: mild in 6 (7.3%), moderate in 4 (4.9%) and severe in 2 (2.4%). The AUC against PFP was: 0.871 (95% CI 0.789-0.954, p<0.001) for FRAIL scale and 0.870 (95% CI 0.791-0.948, p<0.001) for EFS (Figure 1).

Conclusion

Frailty is prevalent in patients with long-standing SSc, and most of them are considered pre-frail or vulnerable. Low physical activity, muscle weakness and exhaustion are among the most frequent clinical aspects of the frailty phenotype. Both FRAIL scale and EFS showed overlapping diagnostic accuracy against PFP as the reference standard, and FRAIL scale seems to be more feasible than EFS.

References

[1]Rockwood MR, MacDonald E, Sutton E, Rockwood K, Baron M. Frailty index to measure health status in people with systemic sclerosis. J Rheumatol. 2014;41(4):698-705.

[2]Morley JE, Vellas B, Abellan van Kan G, et al. Frailty consensus: a call to action. J Am Med Dir Association. 2014;14(6):392-7.

[3]Fried LP, Tangen CM, Walston J, et al. Frailty in older adults: evidence for a phenotype. J Gerontol A Biol Sci Med Sci. 2001;56(3):M146-56.

[4]van Kan GA, Rolland YM, Morley JE, Vellas B. Frailty: Toward a Clinical Definition. J Am Med Dir Assoc. 2008;9(2):71-2.

[5]Rolfson DB, Majumdar SR, Tsuyuki RT, Tahir A, Rockwood K. Validity and reliability of the Edmonton Frail Scale. Age Ageing. 2006;35(5):526-9.

Disclosure of Interests

None declared

Physical and mental health impact of COVID-19 on children, adolescents, and their families: The Collaborative Outcomes study on Health and Functioning during Infection Times - Children and Adolescents (COH-FIT-C&A)

BACKGROUND

The COVID-19 pandemic has altered daily routines and family functioning, led to closing schools, and dramatically limited social interactions worldwide. Measuring its impact on mental health of vulnerable children and adolescents is crucial.

METHODS

The Collaborative Outcomes study on Health and Functioning during Infection Times (COH-FIT - www.coh-fit.com) is an on-line anonymous survey, available in 30 languages, involving >230 investigators from 49 countries supported by national/international professional associations. COH-FIT has thee waves (until the pandemic is declared over by the WHO, and 6-18 months plus 24-36 months after its end). In addition to adults, COH-FIT also includes adolescents (age 14-17 years), and children (age 6-13 years), recruited via non-probability/snowball and representative sampling and assessed via self-rating and parental rating. Non-modifiable/modifiable risk factors/treatment targets to inform prevention/intervention programs to promote health and prevent mental and physical illness in children and adolescents will be generated by COH-FIT. Co-primary outcomes are changes in well-being (WHO-5) and a composite psychopathology P-Score. Multiple behavioral, family, coping strategy and service utilization factors are also assessed, including functioning and quality of life.

RESULTS

Up to June 2021, over 13,000 children and adolescents from 59 countries have participated in the COH-FIT project, with representative samples from eleven countries.

LIMITATIONS

Cross-sectional and anonymous design.

CONCLUSIONS

Evidence generated by COH-FIT will provide an international estimate of the COVID-19 effect on children's, adolescents' and families', mental and physical health, well-being, functioning and quality of life, informing the formulation of present and future evidence-based interventions and policies to minimize adverse effects of the present and future pandemics on youth.

The collaborative outcomes study on health and functioning during infection times in adults (COH-FIT-Adults): Design and methods of an international online survey targeting physical and mental health effects of the COVID-19 pandemic

BACKGROUND

. High-quality comprehensive data on short-/long-term physical/mental health effects of the COVID-19 pandemic are needed.

METHODS

. The Collaborative Outcomes study on Health and Functioning during Infection Times (COH-FIT) is an international, multi-language (n=30) project involving >230 investigators from 49 countries/territories/regions, endorsed by national/international professional associations. COH-FIT is a multi-wave, on-line anonymous, cross-sectional survey [wave 1: 04/2020 until the end of the pandemic, 12 months waves 2/3 starting 6/24 months threreafter] for adults, adolescents (14-17), and children (6-13), utilizing non-probability/snowball and representative sampling. COH-FIT aims to identify non-modifiable/modifiable risk factors/treatment targets to inform prevention/intervention programs to improve social/health outcomes in the general population/vulnerable subgrous during/after COVID-19. In adults, co-primary outcomes are change from pre-COVID-19 to intra-COVID-19 in well-being (WHO-5) and a composite psychopathology P-Score. Key secondary outcomes are a P-extended score, global mental and physical health. Secondary outcomes include health-service utilization/functioning, treatment adherence, functioning, symptoms/behaviors/emotions, substance use, violence, among others.

RESULTS

. Starting 04/26/2020, up to 14/07/2021 >151,000 people from 155 countries/territories/regions and six continents have participated. Representative samples of ≥1,000 adults have been collected in 15 countries. Overall, 43.0% had prior physical disorders, 16.3% had prior mental disorders, 26.5% were health care workers, 8.2% were aged ≥65 years, 19.3% were exposed to someone infected with COVID-19, 76.1% had been in quarantine, and 2.1% had been COVID 19-positive.

LIMITATIONS

. Cross-sectional survey, preponderance of non-representative participants.

CONCLUSIONS

. Results from COH-FIT will comprehensively quantify the impact of COVID-19, seeking to identify high-risk groups in need for acute and long-term intervention, and inform evidence-based health policies/strategies during this/future pandemics.

A prospective, single arm study of intraosseous basivertebral nerve ablation for the treatment of chronic low back pain: 12-month results

Background

The basivertebral nerve (BVN) has been a recently discovered target as a potential source for vertebrogenic chronic low back pain (CLBP). Prior randomized controlled trials have demonstrated safety and efficacy of BVN ablation for vertebrogenic CLBP, but minimal data exists regarding BVN ablation’s clinical effectiveness with broader application outside of strict trial inclusion criteria.

Methods

Prospective, single arm, open label effectiveness trial of 48 patients from community spine and pain practices treated with BVN ablation. Inclusion criteria required more than 6 months of CLBP and type 1 or 2 Modic changes on MRI to be enrolled. Patients were followed post procedure for 12 months using ODI, VAS, EQ-5D-5L and SF-36 patient reported outcome metrics.Results: 47 patients successfully received BVN ablation and 45 patients completed 12 months of follow up. Mean reduction in ODI at 12 months was 32.31 +/- 14.07 (p<0.001) with 88.89% (40/45) patients reporting a ≥15 point ODI decrease at 12 months. Mean VAS pain score decrease was 4.31+/-2.51 at 12 months (p<0.001) and more than 69% reported a 50% reduction in VAS pain scale. Similarly, SF-36 and EQ-5D-5L scores improved 26.27+/-17.19 and 0.22+/-0.15 (each p<0.001).

Conclusions

This data supports the clinical effectiveness of BVN ablation in the community practice setting, with similar 12 month improvements in patient reported outcomes as seen in previously published randomized control trials.

FRI0243 SARCOPENIA IS ASSOCIATED WITH MALNUTRITION IN PATIENTS WITH SYSTEMIC SCLEROSIS

Background:

Sarcopenia is one of the major health problems in older patients and is defined as a progressive decrease in muscle mass and function1. Sarcopenia has only rarely been studied in systemic sclerosis (SSc) and its impact in clinical characteristics of SSc is poorly investigated.

Objectives:

To evaluate the associations between sarcopenia and clinical features in SSc patients.

Methods:

Cross-sectional study, including 82 patients who met the ACR/EULAR 2013 classification criteria for SSc. Dual-energy X-ray absorptiometry, handgrip strength, and short physical performance battery were used to assess sarcopenia according the European Working Group on Sarcopenia in Older People’s (EWGSOP) diagnostic criteria updated in 20191. Malnutrition was evaluated according to the European Society of Clinical Nutrition and Metabolism (ESPEN)2, using the Malnutrition Universal Screening Tool (MUST) to screen risk for malnutrition.

Results:

The mean age was 60.4 years and 91.5% were women (table 1). Sarcopenia was identified in 15 (18.3%) SSc patients. Malnutrition was diagnosed in 12 (14.6%) and was more common in patients with sarcopenia (P=0.038). Also, there were significant differences between patients with and without sarcopenia regarding Body Mass Index (P=0.001), Fat Free Mass Index (P<0.001), knee extension strength (P=0.049), and Timed Up and Go test (P=0.041). There were no differences regarding age, disease duration, Rodnan skin score (mRSS), FVC and DLCO.

Table 1.

Clinical characteristics of SSc patients with and without sarcopenia. Data presented as number (%) of patients, except when indicated otherwise.

Patients featuresWhole(n=82)SSc patients without sarcopenia(n=67)SSc patients with sarcopenia(n=15)PvalueFemales75 (91.5)62 (92.5)13 (86.6)0.606Caucasian68 (82.9)53 (79.1)15 (100)0.258Age (years)b60.4 (10.6)60.2 (10.3)61.5 (12.3)0.678Diffuse skin involvement16 (19.5)16 (23.8)0 (0)0.082Disease duration (years)a12.8 (7.5, 19.2)12.7 (7.1,19.2)13.4 (8.9, 19.8)0.324Rodnan skin scorea4.0 (2.0, 10.0)5.0 (2.0, 10.0)2.0 (2.0,10.0)0.076Interstitial lung disease on HRCT32 (39.5)25 (37.3)7 (10.4)0.737FVC (% predicted)b88.4 (16.6)88.4 (16.9)88.3 (15.3)0.991DLCO (% predicted)b63.7 (11.9)63.6 (12.2)64.2 (11.2)0.855BMI (kg/m2)b25.6 (4.6)26.5 (4.4)21.8 (4.1)0.001FFMI (kg/m2)b15.6 (1.7)16.1 (1.6)13.8 (1.2)<0.001FMI (kg/m2)b9.5 (3.7)9.9 (3.6)7.5 (3.5)0.023Malnutrition12 (14.6)7 (10.4)5 (33.3)0.038MUST - Low risk58 (70.7)51 (76.1)7 (46.7)0.046Moderate and high risk24 (29.3)16 (23.9)8 (53.3)HAQb0.778 (0.591)0.797 (0.575)0.833 (0.576)0.825Timed Up and Go test (s)a8.41 (7.41, 10.59)8.39 (7.5, 9.4)10.23 (7, 14)0.041Knee extension strength (kgf)a21.40 (15.65, 27.52)21.70 (18.05, 28.35)14.82 (9.5, 24)0.049

aMedian (25, 75thpercentiles)

bMean (standard deviation)

Abbreviations: BMI: body mass Index; DLCO: diffusion capacity of carbon monoxide; FFMI: fat free mass index; FMI: fat mass index; FVC: forced vital capacity; HAQ: Health Assessment Questionnaire; HRCT: high-resolution computed tomography; MUST: Malnutrition Universal Screening Tool; SSc: systemic sclerosis.

Conclusion:

Sarcopenia is relatively common and is associated with malnutrition in patients with SSc. In our population, sarcopenia was not associated with other features related to a more severe disease. The role of sarcopenia in the prognosis of SSc needs to be better understood in longitudinal studies.

References:

[1]Cruz-Jentoft AJ, Bahat G, Bauer J, et al. Sarcopenia: Revised European consensus on definition and diagnosis. Age Ageing. 2019;48(1):16-31.

[2]Cederholm T, Bosaeus I, Barazzoni R, et al. Diagnostic criteria for malnutrition - An ESPEN Consensus Statement. Clin Nutr. 2015;34(3):335-40

Disclosure of Interests:

Vanessa Hax: None declared, Rafaela Cavalheiro do Espírito Santo: None declared, Emerson Pena: None declared, Luísa Rodrigues: None declared, Renata Ternus Pedo: None declared, Jordana Miranda de Souza Silva: None declared, Nicole Pamplona Bueno de Andrade: None declared, Andrese Aline Gasparin: None declared, Ricardo Xavier Consultant of: AbbVie, Pfizer, Novartis, Janssen, Eli Lilly, Roche, Rafael Mendonça da Silva Chakr: None declared

Lower Body Weight in Rats Under Hypobaric Hypoxia Exposure Would Lead to Reduced Right Ventricular Hypertrophy and Increased AMPK Activation

Background

Both chronic hypoxia (CH) and long-term chronic intermittent hypoxia (CIH) exposure lead to right ventricular hypertrophy (RVH). Weight loss is an effective intervention to improve cardiac function and energy metabolism in cardiac hypertrophy. Likewise, caloric restriction (CR) also plays an important role in this cardioprotection through AMPK activation. We aimed to determine the influence of body weight (BW) on RVH, AMPK and related variables by comparing rats exposed to both hypoxic conditions.

Methods

Sixty male adult rats were separated into two groups (n = 30 per group) according to their previous diet: a caloric restriction (CR) group and an ad libitum (AL) group. Rats in both groups were randomly assigned to 3 groups: a normoxic group (NX, n = 10), a CIH group (2 days hypoxia/2 days normoxia; n = 10) and a CH group (n = 10). The CR group was previously fed 10 g daily, and the other was fed ad libitum. Rats were exposed to simulated hypobaric hypoxia in a hypobaric chamber set to 428 Torr (the equivalent pressure to that at an altitude of 4,600 m above sea level) for 30 days. Measurements included body weight; hematocrit; serum insulin; glycemia; the degree of RVH (Fulton's index and histology); and AMPK, mTOR, and PP2C expression levels in the right ventricle determined by western blotting.

Results

A lower degree of RVH, higher AMPK activation, and no activation of mTOR were found in the CR groups exposed to hypobaric hypoxia compared to the AL groups (p < 0.05). Additionally, decreased glycemia and serum insulin levels were observed. Interestingly, PP2C expression showed an increase in the AL groups but not in the CR groups (p < 0.05).

Conclusion

Maintaining a low weight before and during exposure to high-altitude hypoxia, during either CH or CIH, could prevent a major degree of RVH. This cardioprotection would likely be due to the activation of AMPK. Thus, body weight is a factor that might contribute to RVH at high altitudes.

P6480Asymmetric dimethylarginine (ADMA) predicts altitude-associated hypoxic pulmonary arterial hypertension

Acknowledgement/Funding

CONICYT/FONDEF/FONIS Sa 09I20007; FIC Tarapaca BIP 30477541-0; BMBF grant 01DN17046 (DECIPHER); Georg & Jürgen Rickertsen Foundation, Hamburg

Effects of practice change on outcomes of extremely preterm infants with patent ductus arteriosus

AIM

To determine whether a decrease in patent ductus arteriosus (PDA) treatment or ligation in extremely preterm (EP) infants was associated with changes in rates of mortality and/or morbidities.

METHODS

Observational study on EP infants admitted from 2008 to 2015. The small baby guidelines do not mandate ligation, however, in late 2010 the guidelines were amended based on new literature suggested that ligation may increase rates of morbidities.

RESULTS

There were 717 EP infants admitted during the study period. There were no significant changes in gestational age, birthweight or annual admissions during the study period. The annual rate of PDA medical treatment declined significantly (R = 0.83, p = 0.01), while the annual rate of PDA ligation declined substantially (R = 0.88, p = 0.004). The annual mortality rate also declined significantly (R = 0.81, p = 0.014). The annual rates of bronchopulmonary dysplasia (BPD), necrotising enterocolitis and intraventricular haemorrhage did not change significantly.

CONCLUSION

In this cohort of EP patients, the rate of PDA ligation decreased substantially since 2010, with no apparent adverse effects on mortality or rates of BPD. These data are consistent with the concept that ligation does not improve outcomes in EP infants.

[Prevalence of overweight and obesity in 9 and 10 year-old children in the Principality of Asturias: evaluation bias by parents]

INTRODUCTION

Overweight and obesity in children is a very important issue in the field of health. The aim of this study was to determine the prevalence of overweight and obesity in pre-adolescent children aged 9 to 10 years old in the Principality of Asturias, and to assess the reliability of the measurements of weight and height reported by parents.

MATERIAL AND METHOD

A sample of 291 subjects, 142 girls and 149 boys were chosen at random from the network of schools in the Principality of Asturias. They were weighed and measured individually at the school. All participants brought the signed consent of their parents, which also contained the anthropometric measurements of they made of their children.

RESULTS

The results showed that 28.17% of children aged 9 and 10 years old in the Principality of Asturias were overweight and 15.80% obese. This means that 44% of the sample had some degree of overweight. Data reported by parents underestimated the weight of both the boys and girls by an average of 2.07kg.

CONCLUSIONS

The high percentage of excess weight observed is due to the categorisation system used (IOFT) and the age of the sample. The results call into question the research with data indirectly recorded data.

Nuclear organization and dynamics of transcription sites in rat sensory ganglia neurons detected by incorporation of 5'-fluorouridine into nascent RNA

In this study we have used the transcription assay with 5'-fluorouridine incorporation into nascent RNA to analyze the nuclear organization and dynamics of transcription sites in rat trigeminal ganglia neurons. The 5'-FU administrated by i.p. injection was successfully incorporated into nuclear domains containing actively transcribing genes of trigeminal neurons. 5'-Fluorouridine RNA-labeling was detected with immunocytochemistry at light and electron microscopy levels. The 5'-fluorouridine incorporation sites were detected in the nucleolus, particularly on the dense fibrillar component, and in numerous transcription foci spread throughout the euchromatin regions, without preferential positioning at the nuclear periphery or in the nuclear interior. Double labeling experiments to combine 5'-fluorouridine incorporation with molecular markers of nuclear compartments showed the absence of transcription sites in Cajal bodies and nuclear speckles of splicing factors. Similarly, no 5'-fluorouridine labeling was detected in well-characterized chromatin silencing domain, the telomeric heterochromatin. The specificity and sensitivity of the run-on transcription assay in trigeminal ganglia neurons was verified by the i.p. administration of the transcription inhibitor actinomycin D. The dramatic reduction in RNA synthesis upon actinomycin D treatment was associated with two important cellular events, heterochromatin silencing and formation of DNA damage/repair nuclear foci, demonstrated by the expression of tri-methylated histone H4 and phosphorylated H2AX, respectively. 5'-Fluorouridine incorporation in animal models provides a useful tool to investigate the organization of gene expression in mammalian neurons in both normal physiology and experimental pathology systems.

Neuronal body size correlates with the number of nucleoli and Cajal bodies, and with the organization of the splicing machinery in rat trigeminal ganglion neurons

Trigeminal ganglion neurons comprise three main cell body-size types. This cell size heterogeneity provides an excellent neuronal model to study the cell size-dependent organization and dynamics of the nucleoli, Cajal (coiled) bodies (CBs), and nuclear speckles of pre-mRNA splicing factors, nuclear structures that play a key role in the normal neuronal physiology. We have analyzed the number of nucleoli and CBs and the structural and molecular organization of CBs and nuclear speckles in the three neuronal types by using immunofluorescence with antibodies that recognize nucleoli (fibrillarin), CBs (coilin), and nuclear speckles (snRNPs), confocal microscopy, and electron microscopy. Whereas the mean number of nucleoli per neuron decreases as a function of cell size, the number of CBs per cell significantly increases in large neurons in comparison with the small ones. In addition, large neurons have a higher proportion of CBs associated with the nucleolus. In all neuronal types, CBs concentrate coilin, fibrillarin, snRNPs, and the survival motor neuron protein (SMN). Immunostaining for snRNPs shows small speckle domains and extensive areas of diffuse nucleoplasmic signal in large neurons, in contrast with the large nuclear speckles found in small neurons. Furthermore, flow cytometric analysis shows that all neurons are in the range of diploid cells. These findings indicate that the fusion behavior of nucleoli, the formation of CBs and their relationships with the nucleolus, as well as the compartmentalization of the pre-mRNA splicing machinery, is related to cell body size in the trigeminal ganglion neurons. Because transcriptional activity is a basic determinant mechanism of cell size in diploid cells, we suggest that our findings reflect a distinct transcription-dependent organization of the nucleolus and splicing machinery in the three cell types of trigeminal ganglion neurons.

Stress-induced activation of c-Jun N-terminal kinase in sensory ganglion neurons: accumulation in nuclear domains enriched in splicing factors and distribution in perichromatin fibrils

In response to cellular stress, the activation of the JNK cascade mediates phosphorylation of c-Jun that promotes its transactivation, which in turn activates the transcription of specific genes. In an experimental model of neuronal stress in vivo, by means of immunofluorescence and kinase assays we have found a reversible activation of JNK induced by the administration of the anti-cancer drug Adriamycin. In control neurons, a considerable basal level of the active, phosphorylated JNK was detected in neuronal nuclei, with a speckled distribution in addition to a diffuse nucleoplasmic signal. Adriamycin-induced neuronal stress was associated with a notable increase of this nuclear immunostaining, indicating activation of the JNK pathway which was confirmed by the increase of JNK enzymatic activity, while no changes in the total JNK were detected by Western blots. The JNK neuronal response to stress was also accompanied by an increase in the nuclear immunoreactivity for c-Jun and also by the de novo appearance of a strong nuclear phospho-c-Jun signal. These effects tend to revert to the control situation after 24 h of Adriamycin treatment. The nuclear compartmentalization of phospho-JNK and its substrate c-Jun was analyzed by confocal laser microscopy. Phospho-JNK strongly colocalizes with snRNPs in nuclear speckles, while the former was not concentrated in the coiled bodies. Upon stress induction, both c-Jun and phospho-c-Jun show a nucleoplasmic distribution in euchromatin domains, with the nucleoli free of immunolabeling. Furthermore, the nuclear speckles enriched in phospho-JNK exhibit a very low or undetectable signal with both c-Jun antibodies. Immunogold electron microscopy confirms the accumulation of phospho-JNK in interchromatin granule clusters (nuclear speckles), while in the nucleoplasm this kinase is mainly localized in perichromatin fibrils. Both c-Jun and phospho-c-Jun were also detected in perichromatin fibrils. Double labeling experiments show the colocalization of phospho-JNK and phospho-c-Jun in certain perichromatin fibrils. These results indicate that the neuronal response to the Adriamycin-induced stress is mediated by the activation of the JNK pathway. The accumulation of phospho-JNK in nuclear speckles raises the possibility that this kinase may be involved in the phosphorylation of an unknown splicing factor. Moreover, the colocalization of phospho-JNK and c-Jun in perichromatin fibrils, which are associated with sites of active transcription, suggests that these nuclear structures may be putative sites for the phosphorylation of JNK substrates.

Formation of intranuclear crystalloids and proliferation of the smooth endoplasmic reticulum in schwann cells induced by tellurium treatment: association with overexpression of HMG CoA reductase and HMG CoA synthase mRNA

Administration of tellurium (Te) in weaning rats causes a well-established demyelinating neuropathy induced by the inhibition in myelinating Schwann cells (SC) of the synthesis of cholesterol, a major component of the myelin sheath, at the level of squalene epoxidase. We have used this experimental model of Te neuropathy to study the biogenesis and reorganization of the endomembranes of the nuclear envelope and endoplasmic reticulum (ER) in response to Te treatment by ultrastructural analysis and in situ hybridization for the detection of HMG CoA reductase and synthase mRNA, which encode key enzymes in cholesterol synthesis. The adaptive response of myelinating SC to cholesterol depletion includes cell hypertrophy, the formation of tubular invaginations of proliferating nuclear membranes giving rise to peculiar nuclear inclusions termed crystalloids, and, at the cytoplasmic level, the formation of lamellar bodies of rough ER, proliferation of the smooth ER, and overexpression of HMG CoA reductase and synthase mRNAs. The changes revert after withdrawal of Te treatment. Our results show that the biogenesis and structural organization of both endomembrane systems change dynamically upon Te-induced cholesterol depletion, indicating that this constituent plays a critical role in the organization of nuclear envelope and ER compartments in SC. The results also suggest that the HMG CoA reductase, an integral membrane protein of ER, provides the signal for the extensive membrane assembly. While the physiological meaning of crystalloid remains to be clarified, the hypertrophy of the smooth ER may represent a cytoprotective mechanism involved in detoxification of the neurotoxic agent or its metabolic derivates.

Necrosis of schwann cells during tellurium-induced primary demyelination: DNA fragmentation, reorganization of splicing machinery, and formation of intranuclear rods of actin

We present a cytological, immunocytochemical, and biochemical study of the cell death of mature myelinating Schwann cells (SCs) in the primary demyelinating neuropathy induced by tellurium (Te). Weaned rats were fed a diet containing 1.1% elemental Te. The animals were killed daily within the first week of Te diet. After 4 to 6 days of Te treatment some SCs underwent degeneration and necrosis. By electron microscopy analysis, degenerating SCs showed chromatin condensation, detachment from the nuclear envelope of condensed chromatin clumps, aggregation of interchromatin granule clusters, formation of intranuclear bundles of microfilaments, and cytoplasmic vesiculation. By confocal laser fluorescence microscopy, chromatin regions were stained with the TUNEL method for in situ labeling of DNA fragmentation and exhibited a progressive reduction of histone signal. In addition, splicing small nuclear ribonucleoprotein (snRNP) factors were redistributed in a few large nuclear domains and bright foci of intranuclear actin were observed. DNA electrophoresis revealed a smear pattern of DNA fragmentation in sciatic nerve samples from Te-treated animals. Upon Te treatment, no degradation of the caspase substrates poly (ADP-ribose) polymerase and lamin B was detected by Western blots or immunocytochemistry, respectively. The peculiar structural rearrangement of the transcription and splicing machinery as well as the vesicular degeneration of the cytoplasm in degenerating SCs support an autophagic cell death of the necrotic type. Unlike the apoptosis of pre-remyelinating SCs (11), this caspase independent cell death of necrotic type involves mature pre-demyelinating SCs and eliminates SCs injured by the neurotoxic effect of Te.

[Antigenic diversity of Plasmodium falciparum and serodiagnosis of tropical malaria]

The importance of antigenic diversity in immunogenicity of population of P. falciparum was studied in regard of immunodiagnosis of tropical malaria. The sera from 42 adult non-immune persons with confirmed infection by P. falciparum and from 30 persons from Africa with confirmed infection by P. falciparum were examined with three antigens differing in geographic origin. Antigen A2 Gambia, M94 Thailand, FCQ2 Papua New Guinea were checked. The following results were obtained: 1) In the quantity of polyclonal antibodies detected higher frequency of higher titres and higher GMRT (statistically significant differences) were demonstrated with three antigens in the persons from the endemic areas of malaria. 2) Higher variation (antigenic diversity) in the quantity of polyclonal antibodies (difference up to 6 dilutions) in the non-immune population in contrast to semi-immune population where the differences were only at the level of two fold dilutions. 3) The correspondence of titres of polyclonal antibodies to all three geographically different antigens was statistically significantly (P less than 0.05) more frequent in the sera of semi-immune persons in contrast to non-immune individuals. 4) The results have shown that repeated infections in endemic areas of malaria with antigenically diverse strains induce the formation of polyclonal antibodies against all antigenic varieties and are better detectable by antigen of any antigenic variety.(ABSTRACT TRUNCATED AT 250 WORDS)