The data project: a shared approach between stakeholders of the healthcare system in definition of a therapeutic algorithm for inflammatory arthritis

Rheumatic musculoskeletal diseases or RMD [rheumatoid arthritis (RA) and spondyloarthritis (SpA)] are systemic inflammatory diseases for which there are no biomarkers capable of predicting treatments with a higher likelihood of response in naive patients. In addition, the expiration of the anti-TNF blocking drugs' patents has resulted in the availability of anti-TNF biosimilar drugs with the same efficacy and safety than originators but at significantly reduced prices. To guarantee a personalized therapeutic approach to RMD treatment, a board of rheumatologists and stakeholders from the Campania region, Italy, developed a clinically applicable arthritis therapeutic algorithm to guide rheumatologists (DATA project). The general methodology relied on a Delphi technique forecast to produce a set of statements that summarized the experts' consensus. Selected clinical scenarios were discussed in light of the available evidence, and there were two rounds of voting on the therapeutic approaches. Separate discussions were held regarding rheumatoid arthritis, psoriatic arthritis, and ankylosing spondylitis. The decision-making factors for each disease were clinical presentation, demographics, and comorbidities. In this paper, we describe a virtuous process between rheumatologists and healthcare system stakeholders that resulted in the development of a shared therapeutic algorithm for RMD patients naive to bDMARDs.

AB0936 Neuropathic pain in Psoriatic Arthritis: analysis of populations treated with anti TNF and anti IL17

Background

Psoriatic arthritis (PsA) is a disease characterized by chronic pain and it is often associated with the presence of fibromyalgia (FMS) with an estimated prevalence of 18%. Several studies demonstrated the central role of neuropathic pain in FMS. However, patients with inflammatory diseases such as PsA frequently complain of complex pain symptoms, with neuropathic characteristics. Therefore, in PsA we can recognize both an inflammatory pain and a neuropathic pain that can be exacerbated both by the concomitant fibromyalgia or depending only on the PsA itself. In fact, In the context of PsA, the presence of neuropathic pain features has been documented in 28% of patients. This could be a reason why the low remission rate in these patients. Finally, Studies on murin models revealed a possible role of IL17, key cytokine of PsA pathogenesis, in mechanism of neuropathic pain.

Objectives

To evaluate the role of anti-TNF and antiIL-17 in neuropathic pain in PsA patients treated with the first biological drug (bDMARDS).

Methods

A cross-sectional evaluation was conducted on 38 PsA patients classified by Classification criteria for Psoriatic Arthritis (CASPAR), referred to the PsA outpatient clinic of “University of Campania Luigi Vanvitelli”. Thirty patients were treated with anti-TNF (mean age 53 years, 17F, 13M), 8 were treated with anti-IL17 (mean age 50 years, 5F, 3M), for almost 6 months. For each patient, an assessment of disease activity using DAPSA and physical function was carried out. The presence of comorbid fibromyalgia syndrome (FMS) was evaluated according to ACR 2016 criteria. We investigated neuropathic pain features through the PainDETECT Questionnaire (PDQ).

Results

Nine patients treated with anti TNF were in DAPSA remission; 18 patients had low disease activity, 3 had High disease activity, FMS was detected in 11 of 30 patients, no one in DAPSA remission for PsA. Characteristics of neuropathic pain (PDQ ≥ 19) were found in 13 (43.3%) patients overall; unlikely neuropathic pain (PDQ < 12) in 16 (53.3%) patients. In the first group 7 patients had FMS, in the second group 3 had FMS. So, our analysis revealed the presence of neuropathic pain in 6 patients (54,5%) with PsA treated with antiTNF with no FMS; all of them were in low disease activity. The same analysis was conducted on anti IL17 treated population: 4 patients were in DAPSA remission, 2 patients in low disease activity, 2 patients in high, disease activity. FMS was diagnosed in 3 patients, 1 of them was in DAPSA remission for PsA. PDQ>19 was found only in 1 patient, who had FMS in comorbidity; the others had no neuropathic pain. So, we had no PsA patient treated with antiIL17, that manifested symptoms of neuropathic pain.

Conclusion

The contribute of IL-17 in developing of neuropathic pain suggests the possible role of anti IL17 as therapy; our results support this tesis suggesting a possible role of anti IL17 in treatment of neuropathic pain. A limit to our work is given by the low sample size for which further studies are necessary to confirm this data.

References

[1]Ramjeeawon A, Neuropathic-like pain in psoriatic arthritis: evidence of abnormal pain processing. Clin Rheumatol. 2019;

[2]Sun C, IL-17 contributed to the neuropathic pain following peripheral nerve injury by promoting astrocyte proliferation and secretion of proinflammatory cytokines. Mol Med Rep. 2017

[3]Martinez-Lavin M: Fibromyalgia is a neuropathic pain syndrome. J Rheumatol 2006;

Disclosure of Interests

None declared

AB1198 PREVALENCE AND PSYCHOPATHOLOGICAL CHARACTERISTICS OF ANXIETY AND DEPRESSIVE SYMPTOMS IN FIBROMYALGIA PATIENTS

Background

Several studies reported higher depression and anxiety rates in fibromyalgia (FM) patients compared to the general population. Furthermore, dysfunctional coping strategies

have been pointed to as intrinsic parts of the pathogenesis of FM.

Objectives

Our study aimed to verify the prevalence of anxiety and depressive symptoms and explore their correlation with physical symptoms as fatigue, sleep, and widespread pain in a cohort of patients diagnosed with FM. We also aimed to determine whether dysfunctional coping strategies might increase the depression and anxiety burden, besides worsening the core symptoms of FM.

Methods

We analyzed a cohort of 105 patients (median age of 53 years 6 M, 99 F) with a diagnosis of FM according to the ACR 2016 criteria. The participants were consecutively recruited from the Fibromyalgia clinic of the University of Campania “Luigi Vanvitelli”. All patients underwent a psychiatric evaluation. We assessed widespread pain by the Widespread Pain Index (WPI) and the presence of fatigue by the Symptom Severity score (SS). Sleep disorders were investigated through Pittsburgh Sleep Quality Index (PSQI). We analyzed mental alterations by Hamilton Depression and Anxiety Rating Scales (HAM-D, HAM-A), and coping strategies by Coping Orientation to Problems Experienced (COPE) Inventory.

The Statistical Package for Social Sciences (SPSS) 22.0 was used; the level of significance was set at p < 0.05.

Results

All patients showed fatigue and widespread pain (100%); sleep disturbances were found in 90.5% of patients and overlapped with all sleep phases. The prevalence of anxiety associated with depression was 75.2%. We found isolated anxiety in 14.3% and isolated depression in 4.8% of patients. We further evidenced a different degree of depression: mild (50.7%), moderate (24.3%), and severe (6.5%). All patients showed depressed mood only if questioned (low tendency to spontaneous verbalization). COPE analysis showed no significant differences in the use of the three coping strategies (Problem-focused, emotion-focused, avoidance-focused). Pearson’s correlation analysis highlighted a negative relationship between problem-focused strategies and the severity of anxiety (r = -0.31, p = .001) and depression (r = -0.32, p = .001). Our analysis also highlighted a positive correlation between fatigue, sleep disturbances, widespread pain, and both anxiety and depression. The analysis of the characteristics of anxiety and depressive symptoms showed a scarce tendency to spontaneous verbalization of depressed mood and ideas of guilt, mostly limited to family relationships, and a sense of ineffectiveness conditioned by the physical symptoms of the disease. Most patients showed psychomotor agitation, psychic and somatic anxiety, poor insight. The analysis of coping strategies adopted showed a negative correlation between problem-focused strategies and anxiety-depressive symptoms, suggesting that such strategies are less frequent in FM patients with comorbid anxiety and depressive symptoms.

Conclusion

Our study confirms the high prevalence of anxiety and depressive symptoms in FM patients. A positive correlation between the pivotal symptoms and anxiety and depressive symptoms may suggest, without implying a cause-and-effect relationship, that psychiatric intervention should be considered along with rheumatologic treatment, to improve both physical symptoms and quality of life. Potentiating problem-focused coping strategies may represent a target to improve anxiety and depressive symptoms.

References

[1]Wolfe et al Revisions to the 2010/2011 FM diagnostic criteria. Semin Arth. Rheum. 2016

Table 1.

Correlation analysis between coping strategies and HAM-D and HAM-A total scores

HAM-DHAM- AProblem-focused Coping- 0,32**- 0,31**Avoidant Coping0,800,92Emotion Coping0,140,13

**p<0.01

Disclosure of Interests

None declared

SAT0601 RELATIONSHIP BETWEEN BODY MASS INDEX AND NAILFOLD CAPILLAROSCOPY IN PRIMARY AND SECONDARY RAYNAUD’S PHENOMENON

Background:

Raynaud’s phenomenon (RP) is a diffuse clinical manifestation (3-5% of general population) RP is often secondary to autoimmune systemic diseases, while the condition is classified primary if no underlying disorders can be found. A lower body mass index (BMI) was associated with a greater risk of developing RP, perhaps due to greatest sensivity to cold temperatures

Objectives:

The objective of our study was to evaluate the association of BMI with clinical and capillaroscopic features in primary and secondary RP.

Methods:

Consecutive patients at the first access to a Rheumatology Outpatient Clinic over a 13 months period were screened to RP; nailfold videocapillaroscopy (NVC)was carried out and qualitative and quantitative assessment was performed. Diagnosis of RP was defined in patients who identified color pictures of witnessed attacks.Patients enrolled were screened for secondary causes of RP. RP was classified as primary when no abnormalities were found. Weight and height were collected in clinical records and patients were divided in 3 groups according to their BMI: underweight (BMI<18.5 kg/m2), normal weight (BMI 18.5–25 kg/m2), and overweight (BMI >25 kg/m2). Chi-square test to compare categorical variable and Parametric Student t-test to comparing mean values of normally distributed data were used. p<0.05 was considered to be statistically significant.

Results:

RP was diagnosticated in 100 of 1416 patients (7.06%). Of these, 73 (10 M, 63F) accepted to undergo NVC. An autoimmune disease was found in 35 patients (47.9%), of which 2 were underweight, 14 normal weight and 19 overweight. Of 38 patients with primary RP,3 were underweight, 23 normal weight and 12 overweight. BMI was significantly higher in secondary RP (p=0.03). Overweight patients with secondary RP were older (p=0.01), but with a disease duration not statistically significant longer (p=0.26). In secondary RP, avascular areas and neoangiogenesis were founded only in overweight patients. Moreover,in secondary RP overweight was correlated with decreased capillary density (p=0-04). There was not association between BMI and capillaroscopic abnormalities in primary RP.

Conclusion:

In our study BMI was correlated with microvascular changes only in patients with secondary RP. Our findings may suggests a role for obesity in the microcirculatory disfunction in the autoimmune diseases. Further studies are needed to generalize results and to find a causative role.

References:

[1]Lemmens HA. Vasa Suppl. 1987;18:10–4.

[2]Le RoyEC,MedsgerTA.ClinExpRheumatol 1992;10;485-8

[3]O Keeffe ST et al Journal Rheumat 1992:19:1415-7

[4]Fraenkel L. Curr Rheumatol Rep. 2002;4(2): 123–8.

[5]MaundrellA et al NY:Spinger New York 2015 p 21-35

[6]Giurgea G. etalArthritis Rheumatol Vol. 67, No. 1, January 2015, pp 238–242

[7]A.Eman et al. Ab / Atherosclerosis 287 (2019) e123-288

Disclosure of Interests:

Rosella Tirri: None declared, Marco Barba: None declared, Ranieri Formica: None declared, Rosaria Irace: None declared, francesco ciccia Grant/research support from: pfizer, novartis, roche, Consultant of: pfizer, novartis, lilly, abbvie, Speakers bureau: pfizer, novartis, lilly, abbvie

Incidental papillary thyroid cancer diagnosis in patient with adult-onset Still's disease-like manifestations

Adult onset Still's disease (AOSD) is a systemic inflammatory disease characterized primarily by a triad consisting of daily fever, arthritis and maculopapular exanthema. The pathogenesis and etiology of AOSD are unknown and the diagnosis, which can be very challenging, is often made by exclusion. Here, we report a case of a 61-year-old woman with a history of mild psoriatic arthritis, fever, arthritis and maculopapular exanthema. Her initial laboratory tests showed neutrophilic leukocytosis, hypertransaminasemia, and markedly elevated levels of the erythrocyte sedimentation rate and C-reactive protein. With a presumptive diagnosis of AOSD, based on Yamaguchi criteria, the patient started an extensive diagnostic work-up to exclude other potential differential diagnoses. With fluorodeoxyglucose (FDG) positron-emission tomography, a thyroid nodule with moderate FDG uptakes was detected. The fine needle aspiration biopsy led to diagnosis of papillary thyroid cancer. The history of psoriatic arthritis, the patient's age, and atypical features of the skin rash described as not concomitant with fever flares, suggested a diagnosis of paraneoplastic AOSD-like manifestations.

Safety of methotrexate in rheumatoid arthritis: a retrospective cohort study in clinical practice

OBJECTIVE

To evaluate the treatment duration with MTX monotherapy or in association with DMARDs or TNFalpha inhibitors and the incidence and typology of adverse events (AE) occurred in rheumatoid arthritis (RA) patients.

METHODS

A retrospective large cohort study of RA outpatients, consecutively seen from January 2000 to June 2005 was performed. Study group were RA patients classified according to the 1984 ACR criteria for the classification of rheumatoid arthritis. The patients were divided in 3 groups according to the treatment regimen: MTX monotherapy, MTX in combination with DMARD or with anti TNFalpha agents. We analyzed 348 therapeutic cycles, 177 of whom using MTX monotherapy.

RESULTS

The 224 RA patients accumulated 800 person-years of follow up. Follow up for each of the groups was: MTX monotherapy 479.4 person-years, MTX in combination with DMARDs 244.5, or with TNFalpha inhibitors, 75.7 person-years. From the Kaplan-Meier analysis, the probability of patients remaining on treatment 5 years was 58.5 after starting MTX. The incidence of any AE was 8.87 per 100 person-years. From all, 69 (97.2%) AE were no severe. Among those, more frequently were observed at gastrointestinal tract (31%), liver (19.7%), skin (15.5%). Incidence of severe AE (lung adenocarcinoma, 1 case; pancreatitis, 1 case) was 0.25 per 100 person-years, occurring in patients taking MTX monotherapy or MTX in combination with DMARDs, respectively.

CONCLUSIONS

These data confirm that methotrexate is well tolerated in clinical practice in the medium-long term. Nevertheless, the occurrence of severe AE require an accurate vigilance for methotrexate toxicity.

Leflunomide in psoriatic arthritis: a retrospective study of discontinuation rate in daily clinical practice compared with methotrexate

OBJECTIVE

To assess the safety profile of leflunomide (LEF) in a two-year retrospective analysis of psoriatic arthritis (PsA) patients (pts) treated in daily clinical practice compared with methotrexate (MTX).

PATIENTS

Fourty-two PsA patients with polyarticular involvement or asymmetrical oligoarticular arthritis, satisfying ESSG criteria for the spondyloarthropathies, treated with LEF monotherapy (10-20mg/die without loading dose) between September, 2004 and August, 2006 were reviewed. They were compared with MTX (7.5-15mg/week) users (44 cases). The adverse events (AEs) and the causes of withdrawal were evaluated.

RESULTS

At 24 months, cumulative survival rate of pts remaining on drugs was 54.9% in LEF users and 57.0% in MTX users (p > 0.05). The discontinuation rate (DR) for toxicity was higher in LEF group (29.2%) than in MTX group (10.8%) (p = 0.07). The occurrence of AEs was more frequently registered in the first year in both groups. LEF monotherapy showed a significant higher crude incidence for any AEs (38.7 events x100 person-years) compared to MTX (14.3 events x100 person-years) (p < 0.001). The cumulative DR for inefficacy was greater but not statistically significant in MTX group than LEF (28.6% vs. 12.6% respectively; p = 0.056). Finally, DR for other causes accounted for 8.7% vs. 11.0% respectively (p > 0.05).

CONCLUSIONS

Our data showed, in a setting of clinical practice, that the rate of PsA pts remaining on drug was comparable between LEF and MTX, and a manageable LEF safety profile during a 24 months of follow-up, even if a greater incidence of DR for AEs was registered than in MTX users.

The predictive value of attributes of pain to classify rheumatoid arthritis

Out of 2300 patients with rheumatic diseases 1627 were analysed to develop a classification of rheumatoid arthritis based on clinical attributes of pain. Of these, 641 patients had the disease and 986 were controls with other rheumatic conditions. For traditional format classification, six of eight variables were selected: pain at a fixed joint; symmetrical pain; continuous pain; pain mainly present at night or in the morning; pain following joint pressure; and pain decreased by load/movement. The occurrence of four or more of these features was associated with a 72.1% sensitivity and a 79.1% specificity. A classification tree constructed on four features that showed the greatest diagnostic power (symmetrical pain, pain mainly present at night or in the morning, pain at joint pressure, continuous pain), was associated with a 75.8% sensitivity and a 77.0% specificity.

Pott's disease of the lower cervical spine in a diabetic patient

Over the last few years, tuberculosis has steadily been returning to the worlds attention as a major health threat. The spinal localization of tuberculosis (Pott's Disease) represents around 1% of the case histories, in 3-5% of which there is cervical involvement. Diabetes mellitus increases the risk of infectious disease and predisposes to tuberculosis. Here, a rare case is presented of Pott's disease in the lower cervical spine, associated with retropharyngeal abscess in a diabetic patient. The aim of this study is to emphasize the importance of early diagnosis in such patients, so that adequate pharmacological and/or surgical treatment can be initiated to avoid serious complications.

Clinical pattern of pain in rheumatoid arthritis

OBJECTIVE

To evaluate whether rheumatoid arthritis (RA) is associated with a characteristic clinical pattern of pain which may be useful as a criterion to differentiate RA from other rheumatic diseases.

METHODS

2300 patients from the ReumaLink data bank project with definite rheumatic diseases were studied. Of these 907 patients (39.5%) fulfilled the ARA/ACR revised criteria for RA, while 1393 had rheumatic diseases other than RA. The following diagnostic attributes of pain were considered: localization, symmetry, continuity, modulation, relationship with time and with loads/movements, tenderness.

RESULTS

After a descriptive analysis, some pain characteristics were selected individually and others were combined. Only 8 variables were considered for a predictive analysis. Univariate analysis showed that symmetric pain is the most potent discriminating item, with 82.2% sensitivity, 69.2% specificity, a 61% positive predictive value and a 83.3% negative predictive value. A higher probability of RA was present in patients with symmetric pain than in those with asymmetric pain (odds ratio = 7.8). A multivariate analysis performed on 1627 patients showed that a specific clinical pattern of pain (symmetrical pain, pain following joint pressure, mainly present at night or in the morning, continuous) could predict RA patients with a 68.9% likelihood. The lack of these symptoms excluded RA with 92% probability.

CONCLUSION

The clinical pattern of pain defined by us can predict RA with a 70% probability. This value reaches 86% when the variables "pain in a fixed joint" and "pain decreased by load/movements" are added. These results indicate that determining the clinical pattern of pain is a useful screening tool for suspected RA, in particular early in the disease course.

[The nephrotic syndrome and pheochromocytoma. A report of a rare clinical case]

In clinical practice, the coincidence of nephrotic syndrome with pheochromocytoma is very rare. The case is described of a 23-year-old woman who in June 1988 presented with recurrent hypertensive crises, severe asthenia, abundant sweats, orthostatic hypertension and massive proteinuria. Diagnostic tests performed (abdominal ultrasound and CT, urinalysis, renal function tests, plasma levels of metanephrine and normetanephrine, as well as urinary VMA determination) revealed the presence of a pheochromocytoma of the left adrenal gland combined with nephrotic syndrome. Surgical removal of the left adrenal led to immediate normalization of blood pressure and absence of urinary abnormalities. The authors therefore suggest either an immunological pathogenesis or one due to glomerular hyperfiltration.

Cardiac involvement in rheumatoid arthritis: an echocardiographic study

Thirty-nine consecutive patients with rheumatoid arthritis (RA) and 40 control subjects were studied by echocardiography in order to assess the incidence of cardiac involvement in this disease. The occurrence of anatomic lesions in our series was lower than that observed in other studies. No differences in mean values of left and right ventricular diastolic function indexes obtained by Doppler echocardiography were found between patients and controls. However, in 26% of patients with RA, left ventricular abnormalities probably secondary to myocardial fibrosis were observed.

Antinuclear antibodies in first-degree relatives of patients with polymyositis-dermatomyositis: analysis of the relationship with HLA haplotypes

Antinuclear antibodies (ANA), as detected by indirect immunofluorescence on HEp-2 cells, have been investigated in five spouses and 41 first-degree relatives of nine probands with polymyositis-dermatomyositis (PM-DM) and in 41 sex- and age-matched controls. ANA were detected in 12 out of the 41 first-degree relatives and in two controls (chi 2 = 6.97; P less than 0.01). HLA typing was done in four out of the nine families; in two of them only, ANA segregated with a haplotype. ANA positivity was not correlated either to sex or to age or to household contact. Our results show that ANA occur in a significant percentage of first-degree relatives of patients with PM-DM. The finding seems to be genetically conditioned.

Evidence for peripheral impaired glucose handling in patients with connective tissue diseases

Sixteen patients suffering from rheumatoid arthritis (RA) (n = 8), systemic lupus erythematosus (SLE) (n = 5), and systemic sclerosis (SSc) (n = 3), and 10 healthy subjects matched for age, sex, and body mass index, were submitted to an intravenous (IV) glucose tolerance test (GTT) (0.33 g/kg of body weight in 3 minutes) and to a euglycemic hyperinsulinemic glucose clamp to study insulin response and action. In the euglycemic clamp, along with the two insulin infusion rates (0.5 mU/kg.min from 0 to 120 minutes and 1 mU/kg.min from 121 to 240 minutes), a primed (20 microCi) continuous (0.2 microCi/min) infusion of 3H-glucose allowed determination of glucose kinetics. Our data show that patients versus controls have (1) a significant increase in basal plasma insulin levels (87.2 +/- 14.8 v 41.3 +/- 6.0 pmol/L, P less than .05); (2) similar glucose-induced acute insulin response; and (3) a lower glucose disappearance rate (Rd), glucose metabolic clearance rate (gMCR), and glucose infusion rate (GIR) when the lowest insulin infusion rate was delivered. These differences disappeared when the insulin infusion rate was doubled. Furthermore, basal plasma insulin levels and glucose disappearance rate significantly correlated with the main inflammatory indices of each disease studied. We conclude that in our patients impaired glucose handling is mainly due to peripheral insulin resistance.

[Clinico-developmental aspects in 44 cases of polymyositis/dermatomyositis]

A retrospective study, paying particular attention to the clinical and evolutive aspects of the disease, was performed on 44 subjects affected by polymyositis/dermatomyositis (PM/DM) and hospitalized at the Institute of Medical Clinics of the 1st School of Medicine of Naples University. On the basis of the different clinical pictures, the cases were classified into the following groups: primary PM (4); primary DM (19); DM/PM associated with malignancy (6); childhood DM/PM (3); PM/DM associated with connective tissue disorders (12). Diagnosis was established in terms of the following criteria: a) symmetrical and mostly proximal bilateral muscle weakness (100%); b) elevation of serum enzymes (86.3%); c) electromyographic findings of myopathy sometimes with fibrillation potentials, increased insertional irritability and pseudo-myotonic discharges (93.1%); d) muscle biopsy changes compatible with a clinical form of polymyositis (83.3% out of 30 cases); e) dermatological manifestations including particularly pink or lilac edema-erythema over the periorbital areas, wine-red maculae, Gottron's sign, "poikiloderma vasculare atrophicans", telangiectasias and skin vasculitis (86.3%). An involvement of the extraneural apparatus and organs was present in 40 patients; the most damaged was the osteoarticular apparatus, followed by esophagus, lung, heart and kidney; such pathology was rarely present in the childhood form. A follow-up of the disease has been performed in 36 cases and the therapy consisted fundamentally of high dose corticosteroids (mostly prednisone), associated, in a minority of cases, with methotrexate. A clinical improvement was observed in most cases and a remission of the disease in part of the latter. However, a worsening of the illness was noticed only in the patients suffering from PM/DM associated with malignancy, and mortality rate was 11.1% in all.

Isolation and characterization of single myocardial cells from the quail, Coturnix coturnix japonica

1. The enzymatic cell isolation technique was applied to the bird heart resulting in myocytes of which 10-50% maintained their spindle-shaped morphology, excluded the vital dye, Evans blue and tolerated physiological concentration of Ca2+ ions. 2. The length of spindle-shaped myocytes was on average 289 +/- 7 microns, and the maximum width was 10.2 +/- 0.3 microns. The mean length of the sarcomeres was 2.18 +/- 0.03 microns. 3. In electron micrographs the fine structure of the spindle-shaped myocytes looked normal--regular sarcomeric organization with clear A and I bands, mitochondria with tightly located cristae and well-developed sarcoplasmic reticulum (SR). 4. Most (80%) of the spindle-shaped myocytes were quiescent in physiological calcium concentration and practically all of them could be induced to twitch by electric field stimulation. Some beat spontaneously showing mostly slowly-propagating (135 +/- 6 microns/sec at 20 degrees C) contraction waves, so-called phasic contractions. Sometimes spontaneous twitch-type contractions could also be seen.

Isolation and characterization of single myocardial cells from the perch, Perca fluviatilis

In applying the enzymatic cell isolation technique to the fish heart about 40% of the dispersed myocytes maintained their spindle-shaped morphology, and about half of them tolerated physiological concentration of Ca2+ and excluded the vital dye, Evans blue. The length of spindle-shaped myocytes was on average 133 +/- 3 micron and the maximum width was 4.2 +/- 0.1 micron. The mean length of the sarcomeres was 2.1 +/- 0.1 micron. The sizes of the myocytes did not vary significantly with the weights of the fish. Electron microscopic examinations showed typical fish myocardial cell structure; absence of transverse tubule system, a sparse network of sarcoplasmic reticulum and from a few up to eight or more myofibrils. The cells were mononuclear. Most of the Ca2+-tolerant myocytes were quiescent, but the contraction in them could be induced by electric field stimulation. Both the spontaneous and electrically triggered contractions were of twitch type. The slowly propagating contraction waves, so-called phasic contractions common in isolated mammalian cardiac myocytes, could not be seen at all.

Alpha and beta adrenergic control of contraction force of perch heart (Perca fluviatilis) in vitro

Noradrenaline showed a negative inotropic effect on the isolated electrically triggered atrium of the perch. The effect was stronger at lower temperature and was antagonized by an alpha adrenergic blocker, phentolamine. The inotropic effect of adrenaline was dependent on incubation temperature. The effect was negative at 15 C but biphasic at 24 C, where with increasing adrenaline concentration a positive inotropic effect was followed by negative inotropy. Phentolamine not only antagonized the negative inotropic effect of adrenaline at 15 degrees C but changed it to positive. This positive inotropic effect was antagonized by a beta adrenergic blocker, propranolol. On the triggered ventricular strip adrenaline had no effect at 6 or 15 C, but increased contraction force at 24 C. It can be suggested that in the perch heart atrium there is an activity balance of alpha and beta receptors, which mediate the negative and positive inotropic control, respectively. As in higher vertebrates, alpha adrenergic activation decreases and beta activation increases by agonists in the following order: noradrenaline, adrenaline and isoprenaline. The balance changes towards increased beta activity when temperature rises.

Effects of acetylcholine, isoprenaline, phenylephrine and dibutyryl-cAMP on the contractility of isolated myocytes of the rat heart ventricles

Single ventricular myocytes were isolated by enzymatic dissociation from the rat heart. The myocytes showed two types of spontaneous contractions: action potential dependent 'electric' contractions which occurred as short bursts, and slowly propagating contraction waves, i.e. phasic contractions. Electric contractions were normally found only in some of the myocytes, but in about 85% of the cells these could be induced by isoprenaline (ISO), phenylephrine (PHE), dibutyryl-cAMP (DB-cAMP) or acetylcholine (ACh). The inducing potency of the drugs was ACh greater than PHE greater than ISO greater than DB-cAMP. When electric contractions were blocked with verapamil, the frequency of phasic contractions was increased by ISO and DB-cAMP, whereas PHE and ACh had not this effect. In 45 min, ISO increased the frequency tenfold. High concentrations (10(-4) and 10(-5) M) of ISO lead to steady contracture of the myocytes in about 40% of the cells. The effect of DB-cAMP was weaker being only about 20% of that of ISO and it never caused steady contractures. The results suggest that alpha receptor activation by PHE does not affect the intracellular calcium movements but that ISO through beta receptor activation and DB-cAMP directly may increase the rate of calcium accumulation by sarcoplasmic reticulum (SR).

Membrane potential oscillations in enzymatically isolated rat myocardial cells

Enzymatical isolation was used for preparation of single myocardial cells, contractions of which were mainly of slow phasic type but normal fast contractions also occurred. Membrane potential (MP) changes of these cells were measured by conventional microelectrode techniques. Initial MP level of these cells varied between -60 to -90 mV (74.4 +/- 1.9). In the majority of the cells the MP rapidly dropped to -20 to -40 mV and continued to decline while oscillating. In some cells MP recovered from -20 to -40 back to a more negative potential, and the MP oscillation was strongest (up to 20 mV) between -30 to -50 mV. In about 3% of the impalements the MPs did not degenerate at all, but stayed at initial values for several minutes. The MP oscillations were dependent on the MP level and connected to the slow phasic contractions. In connection to the normal fast contractions, two types of action potentials (AP) could be registered. Near -50 mV the cells often generated slow APs of duration 200-400 ms and dV/dt less than 3 V/s but at higher MP level normal fast APs up to 120 mV (100-300 ms and dV/dt greater than 40 V/s) were generated. The slow phasic contractions were never connected to either type of AP.

Characterization of contractions in mechanically and enzymatically isolated myocardial cells from the rat heart ventricles

Single spontaneously beating myocardial cells were prepared by mechanical or enzymatical isolation. Using a TV camera and videotape recorder, beating parameters were characterized in different buffer solutions in regard to temperature and integrity of sarcolemma, which was tested by ability of cells to exclude a vital stain, Evans blue. The mechanically disaggregated cells were totally permeable to this stain, but about 60% of the enzymatically isolated myocytes were able to exclude the stain. The myocytes prepared in the presence of calcium were most tolerant to physiological concentration of calcium. Contractions were mainly of phasic type where the velocity of contraction wave was very slow (50-330 microns/s). The velocity was not correlated to the beat rate. Temperature dependence of the velocity was positively correlated with the integrity of sarcolemma. Beat rate was inversely related to the integrity of sarcolemma being slowest in calcium tolerant enzymatically isolated cells. Beat rate of calcium sensitive myocytes was higher but unstable and the temperature dependence of the rate was steeply reduced and even reversed during the incubation. Some calcium tolerant myocytes generated occasionally an electric type of contraction which came in bursts and was characterized by synchronous sarcomere shortening without any contraction wave.

Inhibitory adrenergic control of heart rate of perch (Perca fluviatilis) in vitro

1. Adrenaline and noradrenaline, but not isoprenaline or phenylephrine, showed a negative chronotropic effect on the isolated perch heart. 2. This adrenergic effect was blocked by an alpha-adrenergic antagonist, phentolamine, but not by a beta-blocker, propranolol, suggesting the role of alpha receptors in this action. 3. When a ligature between the atrium and the ventricle was used, adrenaline inhibited the beating of the atrium but not of the ventricle. This suggests that the negative chronotropic effect occurred in the whole heart through an atrial pacemaker (sinus node). 4. The sensitivity of the heart to the adrenergic effect was temperature-dependent and greater at low test temperature. At 15 degrees C pD2 for noradrenaline was 6.45 +/- 0.20 and for adrenaline 6.33 +/- 0.20. At 24 degrees C the values were 5.44 +/- 0.12 and 5.67 +/- 0.15, respectively.

Cholinergic responses in different sections of rat airways

Effect of cholinergic agonists on rat airway smooth muscle were studied, 4 different preparations were used: the trachea and the bronchus representing the extrapulmonary airways, the bronchiole and the parenchymal strip representing the intrapulmonary airways. The dose-dependent isometric contractile responses of these 4 preparations to acetylcholine (ACh) and carbacholine (CCh) were determined. A significant difference in sensitivity to both ACh and CCh was observed between the extrapulmonary and intrapulmonary airways. When pD2-values of these preparations were compared, the trachea and the bronchus showed to be 10--100 times more sensitive to these drugs than the bronchiole and the parenchymal strip. A significant difference between the trachea and the bronchus was also found in the pD2-values to ACh, the bronchus being more sensitive than the trachea. This difference in sensitivity was probably due to a greater activity of cholinesterase (ChE) in the tracheal tissue, for the difference was not seen in response to ACh with physostigmine or to CCh. It is suggested that there are more cholinergic receptors in the tracheal and bronchial smooth muscles than in the muscles of the bronchioles and the parenchymal tissue.

Characterization of contractions in mechanically disaggregated myocardial cells from the rat

Myocardial cell groups, mechanically disaggregated from the rat heart, beat spontaneously in a medium which resembles intracellular fluid. The cells, initially functioning in an uncoordinated way, i.e. each cell in its own rhythm, gradually become coordinated as a function of time. After 90 min of incubation at 15 degrees C all the cell groups were functioning in a coordinated way. The initiation of coordination was temperature-dependent. Lowering the temperature from 15 degrees C to 10 degrees C significantly delays the coordination, only 75% of the cell groups being coordinated after 90 min. The contraction wave in coordinated cell groups was very slow; 90 +/- 7 micrometers/s at 20 degrees C, 100 +/- 6 micrometers/s at 30 degrees C and 100 +/- 7 micrometers/s at 35 degrees C. The velocity of contraction waves was not significantly temperature-dependent, suggesting a neonenzymatical type of propagation. It also seems too slow to be an electrical event. Apparently the contraction waves are propagated by diffusion of Ca2+. The addition of caffeine to the medium hastened the coordination of contractions, but Na-azide strongly inhibited it. The results indicate that the sarcoplasmic reticulum functions in the coordination of contractions, probably by releasing Ca2+ for the activation of the myofilaments.

Alpha-receptor subsensitivity of isolated atria from rats following physical training or repeated ACTH-injections

Decreased chronotropic and inotropic sensitivity of isolated atria to phenylephrine but not to isoprenaline was found in rats following repeated physical training by swimming or repeated ACTH-injections. These changes were induced within a week of subjection of animals to these treatments. It is concluded, that these effects are mediated by increased adrenergic activity which results in this subsensitivity of alpha-receptors.

The effect of cyclophosphamide on the experimental inflammation induced by the toxic mushroom Cortinarius speciosissimus in the rat kidney

A single intraperitoneal dose of cyclophosphamide (150 mg/kg) given at the same time as an oral dose of Cortinarius speciosissimus prevented the renal inflammation induced by this toxic mushroom in the male rat. Furthermore, a scar formation around dilated collecting ducts was clearly reduced by cyclophosphamide treatment. In general the only lesions observed in the cyclophosphamide treated animals were dilated collecting ducts in the outer medullary zone, the epithelia of which were either in regenerative mitosis or were atrophic. Apparently the primary sites of action of Cortinarius toxins in male rats are the collecting ducts of the outer medullary zone. When inflammation and the subsequent scar formation is prevented by cyclophosphamide, the damaged tubules can regenerate by mitotic activity and perhaps restore normal function.

Nephrotoxicity of Cortinarius speciosissimus: a histological and enzyme histochemical study

The nephrotoxicity of the mushroom species Cortinarius speciosissimus was studied in the rat. Dried, homogenized mushroom was given orally via gastric tubing. The development of the kidney damage was followed by both histological and enzyme histochemical methods. The first signs of kidney damage were interstitial infiltrates occurring mainly in the outer medullary zone, observed two days after the administration of the mushroom. Focuses of inflammation, which gradually scarred, appeared after four days. Chiefly necrotic changes occurred in the tubuli of the cortical zone. Valine residue cleaving aminopeptidase disappeared from the necrotic tubuli at a noticeably greater rate than arginine residue cleaving aminopeptidase. A high activity of arginine residue cleaving aminopeptidase was observed in the inflammatory focuses located in the outer medullary zone, showing the important role of this enzyme in kidney inflammation.