Large SSc Research Articles

Arthroscopic Repair of Large Subscapularis Tear Over the First Facet

Background: Long-term studies on arthroscopic repair of large subscapularis (SSC) tears over the first facet with or without supraspinatus (SSP) tear are limited. Purpose: To assess the structural and clinical outcomes of arthroscopic repair of large SSC tears using magnetic resonance imaging (MRI) and identify the factors related to SSC retear and poor outcomes. Study Design: Case series; Level of evidence, 4. Methods: This study involved 109 patients (84.0 ± 36.2 months of follow-up) who underwent arthroscopic repair of large SSC tears (Yoo and Rhee classification type III [n = 81] or IV [n = 28]) between 2011 and 2019. All patients underwent MRI at 6.1 ± 0.4 months after surgery, and 79 of 109 patients (72.5%) were followed up over 7 years. Clinical outcomes (active range of motion, functional scores, and belly press strength) and final poor clinical outcomes (reoperation, osteoarthritic change, and poor clinical outcome) were recorded. SSP tear size, rotator cuff atrophy and fatty infiltration (Goutallier classification), SSC tendon integrity (intact, intermediate, definite tear), and SSP tendon integrity (Sugaya classification) were evaluated by MRI. Results: The overall SSC retear rate was 8.3% (9/109) (type III, 2/81 [2.5%]; type IV, 7/28 [25.0%]; P < .001). SSC Goutallier grade 4 showed a higher retear rate than grade 3 (7/33 [21.2%] vs 2/33 [6.1%]; P = .149). A large SSP tear (in millimeters) (odds ratio [OR], 1.5; P = .003), SSC Goutallier grade 4 (OR, 10.8; P = .047), and SSP Goutallier grade 3 or 4 (OR, 0.02; P = .013) were independent factors for SSC retear. Clinical outcomes, except for external rotation, were poorer in patients with SSC retear than in those without retear. Final poor clinical outcomes were observed in 27 of 79 patients (34.2%); female sex (OR, 7.7; P = .007), SSC retear (OR, 8.2; P = .025), and SSP retear (OR, 4.7; P = .031) were independent factors. Conclusion: Arthroscopic repair of large SSC tears has shown promising structural outcomes for type III tears but not type IV tears. SSC retear was affected by SSC atrophy, as well as SSP tear size and atrophy. Approximately one-third of the final poor clinical outcomes could be predicted, and SSC retear, SSP retear, and female sex were associated with long-term poor clinical outcomes, underscoring the importance of carefully selecting patients for arthroscopic repair of large SSC tears.

Differences in symptom experience among patients with systemic sclerosis: a cluster analytic approach to identifying subgroups.

Symptoms of people who have SSc are heterogeneous and difficult to address clinically. Because diverse symptoms often co-occur and may share common underlying mechanisms, identifying symptoms that cluster together may better target treatment approaches. We sought to identify and characterize patient subgroups based on symptom experience. An exploratory hierarchical agglomerative cluster analysis was conducted to identify subgroups from a large SSc cohort from a single US academic medical centre. Patient-reported symptoms of pain interference, fatigue, sleep disturbance, dyspnoea, depression and anxiety were used for clustering. A multivariate analysis of variance (MANOVA) was used to examine the relative contribution of each variable across subgroups. Analyses of variance were performed to determine participant characteristics based on subgroup assignment. Presence of symptom clusters were tallied within subgroup. Participants (n = 587; 84% female, 41% diffuse cutaneous subtype, 59% early disease) divided into three subgroups via cluster analysis based on symptom severity: (i) no/minimal, (ii) mild, and (iii) moderate. Participants in mild and moderate symptoms subgroups had similar disease severity, but different symptom presentation. In the mild symptoms subgroup, pain, fatigue and sleep disturbance was the main symptom cluster. Participants in the moderate symptoms subgroup were characterized by co-occurring pain, fatigue, sleep disturbance, depression and anxiety. Identification of distinct symptom clusters, particularly among SSc patients who experience mild and moderate symptoms, suggests potential differences in treatment approach and in mechanisms underlying symptom experience that require further study.

Mental Health Care Use and Associated Factors in Systemic Sclerosis: A Scleroderma Patient-Centered Intervention Network Cohort Study.

ObjectiveSystemic sclerosis (SSc) has significant psychosocial implications. We aimed to evaluate the proportion of participants in a large international SSc cohort who used mental health services in a 3‐month period and to evaluate demographic, psychological, and disease‐specific factors associated with use.MethodsBaseline data of participants enrolled in the Scleroderma Patient‐Centered Intervention Network Cohort were analyzed. We determined the proportion that used mental health services and the source of services in the 3 months prior to enrollment. Multivariable logistic regression was used to identify variables associated with service use.ResultsOf the 2319 participants included in the analysis, 417 (18%) used mental health services in the 3 months prior to enrollment. General practitioners were the most common mental health service providers (59%), followed by psychologists (25%) and psychiatrists (19%). In multivariable analysis, mental health service use was independently associated with higher education (odds ratio [OR] 1.07, 95% confidence interval [CI] 1.03‐1.11), smoking (OR 1.06, 95% CI 1.02‐1.11), being retired (OR 0.60, 95% CI 0.38‐0.93), having limited SSc (OR 1.39, 95% CI 1.02‐1.89), and having higher anxiety symptom scores (OR 1.04, 95% CI 1.03‐1.06) and lower self‐efficacy scores (OR 0.90, 95% CI 0.83‐0.97). Variables not significantly associated included age, race, disease manifestations, depression symptom scores, and body image distress.ConclusionAbout 18% of participants in a large international cohort received mental health services in a 3‐month period, of whom the majority received these services from a general practitioner.

Erosive arthritis autoantibodies in systemic sclerosis

ObjectiveWe aimed to evaluate in two large SSc French cohorts the prevalence and associated factors with the autoantibodies linked to erosive arthritis. Methods448 SSc patients were recruited from May 2015 to January 2019. Standardized clinical and laboratory variables were collected in accordance with the EUSTAR database. ELISAs for IgM rheumatoid factor (RF), IgG anti-citrullinated proteins (ACPA) and IgG anti‐carbamylated proteins antibodies (anti-CarP) were all determined in a central laboratory. The prevalence and clinical associations of the different antibodies were investigated. ResultsRF positivity was observed in 113 patients (25%) compared to 39 (9%) for ACPA and 63 (14%) for anti-CarP antibodies. Through multivariate regression analysis, both RF and ACPA positivity resulted to be associated with RA overlap disease (OR 5.7, 95% CI 2.3–13.8 and OR 44.1, 95% CI 15.4–126.3, respectively). Additionally, ACPA was found to be significantly related to synovitis/ tenosynovitis (OR 1.7, 95% CI 1.0–2.6). RF positivity was associated to a "vascular subset" (i.e. any major vascular complication) (OR 2.1, 95% CI 1.3–3.4). Moreover, anti-CarP antibodies were associated with a fibrotic subset and with digital ulcers (OR 2.0, 95% CI 1.1–3.6 and OR 1.9, 95% CI 1.1–3.4). ConclusionWe corroborated that ACPA could be useful in identifying patients with a more prominent joint disease and RA overlap disease. Of the most interest we found that anti-CarP antibodies could be a relevant biomarker related to fibrotic skin and lung disease.

L’échec de la réparation de la coiffe augmente le risque de développer une arthrose gléno-humérale secondaire : suivi à long terme après réparation ouverte des lésions sévères du tendon du sous-scapulaire

BackgroundThe subscapularis musculotendinous unit provides a stabilizing effect on the glenohumeral joint and thus, enables normal active range of motion. As pathologies of the subscapularis tendon (SSC) are diagnosed with increased regularity, treatment strategies and their long-term consequences are of relevant interest. Therefore, the primary objective of this retrospective case series was to evaluate clinical and radiological long-term results after open repair of large SSC tears. HypothesisRepair failure negatively influences clinical outcomes and the progression of secondary glenohumeral osteoarthritis (OA). MethodsBetween 1998 and 2007, 24 patients with traumatic large (Lafosse III and IV) SSC tears were treated with an open transosseous repair technique. Of those, 20 patients (83%) with a mean age of 55±8 years (range, from 31 to 68 years) at the time of surgery were subjected to a long-term follow-up after a mean of 14±3 years (range, from 10 to 18 years). The Subjective Shoulder Value (SSV), the Constant Score (CS), the University of California at Los Angeles (UCLA) Shoulder Score, and the American Society for Shoulder and Elbow Surgeons (ASES) Score were obtained. Magnetic resonance imaging (MRI) was performed to evaluate tendon integrity. The progression of secondary glenohumeral OA from pre- to postoperative was analyzed using the collective instability arthropathy (CIA) score. ResultsOne patient (5%) had to undergo revision surgery due to a symptomatic re-tear of the SSC tendon. Besides that, the mean SSV of the affected shoulder was 83%±12, the CS 78±10, the UCLA 32±2, and the ASES 89±14 points, respectively. MRI revealed a re-tear of the SSC tendon in 4 patients (29%). On the affected shoulder, glenohumeral OA progressed significantly from pre- (CIA, 0.3±0.5) to postoperative (CIA, 1.7±0.9; p=0.003) and was significantly associated with repair failure (p=0.040). ConclusionOpen repair of large SSC tears yielded good clinical long-term results. Nevertheless, repair failure was common and, in the further course, negatively affected clinical outcomes and the progression of secondary glenohumeral OA. Level of evidenceIV; retrospective case series.

The biomechanics of subscapularis repair in reverse shoulder arthroplasty: The effect of lateralization and insertion site.

Functional outcomes of subscapularis (SSc) repair following reverse shoulder arthroplasty (RSA) remains controversial. SSc repair in combination with glenosphere lateralization was reported to yield worse clinical outcomes compared with the non-lateralized glenosphere. The aim of this biomechanical study was to investigate how glenosphere lateralization and different re-insertion sites can affect the biomechanics of the SSc after RSA. Nine patient-specific RSA shoulder models were created from patients' computed tomography scans. Moment arms and SSc length were calculated for abduction, forward flexion, and internal rotation in 20° and 90° abduction for three configurations of glenosphere lateralization (standard/+0, +5, and +10 mm) and three SSc repair sites (native, superior, and inferior) and compared with the native shoulder. When compared with the native shoulder, RSA resulted in large adducting SSc moment arms that were antagonistic to the deltoid. Glenosphere lateralization had no effect on SSc moment arms in any motion. However, lateralization increased SSc tension beyond its anatomic length for +5 and +10 mm of lateralization when attached to its native insertion. A superior SSc repair site created the least adductive moment arm as well as the least amount of SSc lengthening. Increased glenosphere lateralization showed a significant increase in the SSc length, which in combination with its adductive moment arm can be antagonistic to deltoid function. However, a superior SSc repair site may help reduce the adductive SSc moment arm and allow for reduced tension on the repair as its length in that location is less than that of the native SSc. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:888-894, 2020.

Repair failure increases the risk of developing secondary glenohumeral osteoarthritis: A long-term follow-up after open repair of large subscapularis tendon tears

BackgroundThe subscapularis musculotendinous unit provides a stabilizing effect on the glenohumeral joint and thus, enables normal active range of motion. As pathologies of the subscapularis tendon (SSC) are diagnosed with increased regularity, treatment strategies and their long-term consequences are of relevant interest. Therefore, the primary objective of this retrospective case series was to evaluate clinical and radiological long-term results after open repair of large SSC tears. HypothesisRepair failure negatively influences clinical outcomes and the progression of secondary glenohumeral osteoarthritis (OA). MethodsBetween 1998 and 2007, 24 patients with traumatic large (Lafosse III and IV) SSC tears were treated with an open transosseous repair technique. Of those, 20 patients (83%) with a mean age of 55±8 years (range, from 31 to 68 years) at the time of surgery were subjected to a long-term follow-up after a mean of 14±3 years (range, from 10 to 18 years). The Subjective Shoulder Value (SSV), the Constant Score (CS), the University of California at Los Angeles (UCLA) Shoulder Score, and the American Society for Shoulder and Elbow Surgeons (ASES) Score were obtained. Magnetic resonance imaging (MRI) was performed to evaluate tendon integrity. The progression of secondary glenohumeral OA from pre- to postoperative was analyzed using the collective instability arthropathy (CIA) score. ResultsOne patient (5%) had to undergo revision surgery due to a symptomatic re-tear of the SSC tendon. Besides that, the mean SSV of the affected shoulder was 83%±12, the CS 78±10, the UCLA 32±2, and the ASES 89±14 points, respectively. MRI revealed a re-tear of the SSC tendon in 4 patients (29%). On the affected shoulder, glenohumeral OA progressed significantly from pre- (CIA, 0.3±0.5) to postoperative (CIA, 1.7±0.9; p=0.003) and was significantly associated with repair failure (p=0.040). ConclusionOpen repair of large SSC tears yielded good clinical long-term results. Nevertheless, repair failure was common and, in the further course, negatively affected clinical outcomes and the progression of secondary glenohumeral OA. Level of EvidenceIV; retrospective case series.

Severe gastrointestinal disease in very early systemic sclerosis is associated with early mortality.

To examine the incidence, predictors and outcomes associated with severe gastrointestinal (GI) disease in a large inception SSc cohort. SSc subjects with <2 years of disease duration were identified from two multicentre cohorts. Severe GI disease was defined as: malabsorption, hyperalimentation, pseudo-obstruction and/or ⩾10% weight loss in association with the use of antibiotics for bacterial overgrowth or oesophageal stricture. Kaplan-Meier, multivariate logistic regression and Cox proportional hazard analyses were performed to determine the cumulative incidence rate, independent clinical correlates and mortality rate associated with severe GI disease. A longitudinal mixed model was used to assess the impact of severe GI disease on the Short Form Health Survey. In this inception SSc cohort, the probability of developing severe GI disease was estimated at 9.1% at 2 years and 16.0% at 4 years. In multivariate analysis, severe GI disease was associated with inflammatory myositis (odds ratio 4.68, 95% CI 1.65, 13.24), telangiectasias (odds ratio 2.45, 95% CI 1.19, 5.04) and modified Rodnan skin score (odds ratio 1.03, 95% CI 1.01, 1.07). Severe GI disease was associated with a >2-fold increase in the risk of death (hazard ratio 2.27, 95% CI 1.27, 4.09) and worse health-related quality of life [Short Form Health Survey physical (β = -2.37, P = 0.02) and mental (β = -2.86, P = 0.01) component summary scores]. Severe GI disease is common in early SSc and is associated with significant morbidity and increased mortality. More research is needed to understand, prevent and mitigate severe GI disease in SSc.

Presence of anti-eukaryotic initiation factor-2B, anti-RuvBL1/2 and anti-synthetase antibodies in patients with anti-nuclear antibody negative systemic sclerosis.

Autoantibodies targeting ubiquitously expressed nuclear antigens can be identified in most patients with SSc. Cytoplasmic autoantibodies (in otherwise ANA-negative sera) targeting eukaryotic initiation factor-2B (anti-eIF2B) have recently been identified in SSc with clinical associations to dcSSc disease and interstitial lung disease (ILD), although the majority of samples originated from a tertiary SSc-ILD centre. We investigated the prevalence and clinical associations of recently described SSc-specific (including anti-eIF2B) and other cytoplasmic autoantibodies in ANA-negative sera obtained from a large representative SSc cohort. ANA-negative sera from the Scleroderma Family Registry and DNA Repository underwent indirect immunofluorescence, radiolabelled protein immunoprecipitation (± immunodepletion) to identify anti-eIF2B and other CTD-related autoantibodies. The clinical phenotype of positive samples was evaluated. Immunoprecipitation was performed on 128 ANA-negative samples (obtained from 3249 SSc patients). Anti-eIF2B antibodies were present in nine patients (7%), the majority of whom had dcSSc (8/9). SSc-ILD was present in all anti-eIF2B patients for whom chest imaging was available (7/9). Anti-synthetase autoantibodies (targeting PL12, PL7, OJ and Zo) were identified in seven patients (5.5%), all of whom fulfilled the 2013 ACR/EULAR classification criteria for SSc and had evidence of SSc-ILD where relevant outcomes were available for evaluation. Anti-RuvBL1/2 antibodies were identified in two patients with SSc-overlap syndromes. Anti-eIF2B antibodies are cytoplasmic SSc-specific autoantibodies with strong clinical associations with dcSSc and SSc-ILD found in ANA-negative sera. Anti-synthetase autoantibodies, and other recently discovered SSc-specific antibodies such as anti-RuvBL1/2, can also be identified in ANA-negative SSc.

Systemic sclerosis and silica exposure: a rare association in a large Brazilian cohort.

The objective of this study is to describe the characteristics of patients with Erasmus syndrome (ES) in a large SSc Brazilian cohort. Nine hundred and forty-seven SSc patients attended at the Scleroderma Outpatient Clinic at two academic medical centers in Brazil and classified as SSc according to the ACR/EULAR criteria were retrospectively studied. Information on demographics, clinical, and laboratory features was obtained by chart review. ES patients had their HLA class II characterized by PCR-SSO method as available. Among the 947 SSc patients studied, nine (0.9 %) had ES. These ES patients were predominantly male (78 %) and smokers (68 %) and presented diffuse SSc (67 %). Mean time of occupational exposure to silica was 13.7 years, with mean age at onset of 47 years. Previous history of tuberculosis was referred by 33 % of the ES patients. All the ES patients presented Raynaud's phenomenon, esophageal involvement, and interstitial lung disease (ILD). Antinuclear antibodies were present in all the ES patients, while anti-topoisomerase I was positive in 44 % and no patient had anticentromere antibody. Three different HLA-DQB alleles (0506, 0305, and 0303) were observed. Compared to non-ES cases, patients with ES were associated with male gender (p < 0.001), diffuse SSc (p < 0.05), ILD (p < 0.05), positive anti-topoisomerase I antibodies (p < 0.05), and death (p < 0.05). Multivariate analysis did not confirm that silicosis is an independent risk factor for SSc. To conclude, ES was rare in this large SSc cohort, although associated with a bad prognosis.

AB0637 Systemic Sclerosis-Related Auto-Antibodies Are Markers of New Clinical Associations in A Cohort of 328 Brazilian Patients

BackgroundSystemic Sclerosis (SSc) shows a heterogeneous clinical presentation, characterized by marked skin and internal organ fibrosis and vascular dysfunction, associated with immunological abnormalities. A varied panel of SSc-related auto-antibodies has...

AB0631 Anti-Rna Polymerase III and anti Pm/Scl Antibodies: Prevalence and Clinical Associations in A Large Cohort of Spanish Patients with Systemic Sclerosis

BackgroundSome authors postulate that systemic sclerosis's (SSc) heterogenic expression is mostly conditioned by the positivity to any of its specific auto-antibodies.ObjectivesTo assess the prevalence of anti-RNA-polymerase III (RNA-pol III) and...

Radiological thymus alterations in systemic sclerosis: our experience and a review of the literature

Thymus alterations have been related to several autoimmune disorders. In particular, previous studies identified a significant frequency of gland abnormalities by chest high-resolution CT (HRCT) in SSc patients. In this study we aimed to investigate the prevalence of radiological thymic alterations and their correlation with clinical and serological features in a large SSc series. We retrospectively evaluated thymic shape on CT scans of 200 consecutive, unselected SSc patients aged over 30 years The presence of radiological abnormalities, i.e. enlarged gland >13 mm or nodular lesions >7 mm, was correlated with SSc clinico-serological features. Moreover, the patients were also classified using a second thickness cut-off of 7 mm in order to identify incomplete thymic involution. Twenty-four of 200 (12%) SSc patients presented an abnormal thymus at HRCT, including hyperplasic (19/24) and nodular (5/24) glands. Otherwise, using the cut-off of 7 mm for gland thickness and excluding subjects with nodular thymus, 50/195 (25.6%) patients presented an incomplete thymic involution. Thymic radiological alterations are significantly correlated with younger age and diffuse cutaneous SSc. Moreover, an abnormally enlarged thymus tended to be more common in patients with shorter disease duration. The present report on a large series of SSc patients further reinforces previous data present in the literature that includes other cohort studies and a number of anecdotal observations. Even though the actual role of thymus radiological abnormalities remains unclear, possible involvement of the gland in the early phase of immune-mediated SSc pathogenesis might be supposed.

Does C‐Reactive Protein Predict the Long‐Term Progression of Interstitial Lung Disease and Survival in Patients With Early Systemic Sclerosis?

There are no identified clinical markers that reliably predict long-term progression of interstitial lung disease (ILD) in systemic sclerosis (SSc; scleroderma). Elevated C-reactive protein (CRP) levels have been reported in SSc patients. We examined the predictive significance of CRP level for long-term ILD progression in a large early SSc cohort. First, the CRP levels were compared between baseline samples of 266 SSc patients enrolled in the Genetics Versus Environment in Scleroderma Outcome Study cohort and 97 unaffected matched controls. Subsequently, the correlation between CRP levels and concomitantly obtained markers of disease severity was assessed. Serially obtained % predicted forced vital capacity (FVC) was used to examine the long-term ILD progression. The predictive significance of CRP level was investigated by a joint analysis of longitudinal measurements (serial FVCs up to 13 years) and survival data. This approach allowed inclusion of all 1,016 FVC measurements and accounted for survival dependency. We confirmed that baseline CRP levels were higher in SSc patients than controls. CRP levels were associated with absence of anticentromere antibodies and correlated with the concomitant severity of lung, skin, and joint involvement. More importantly, higher baseline CRP levels were associated with shorter survival (P < 0.001) and predicted the long-term decline in FVC independent of potential confounders (age at baseline, sex, ethnicity, disease type, current smoking, body mass index, topoisomerase status, and treatment with immunosuppressive agents) in the multivariable model (P = 0.006). Baseline CRP levels are predictive of long-term ILD progression. CRP level might aid clinicians in identifying patients that require more intensive monitoring and treatment.

Disturbed angiogenesis in systemic sclerosis: high levels of soluble endoglin

SSc is a CTD characterized by early generalized microangiopathy with disturbed angiogenesis. Soluble endoglin (sENG), a serum anti-angiogenic protein, has recently been described as a major actor in pre-eclampsia, another severe vascular disease with abnormal angiogenesis. The aim of this study was to investigate, in a cross-sectional study, sENG levels together with other serum vascular markers. Serum levels of sENG were assessed by ELISA in consecutive SSc patients and controls matched for age and sex. We also measured by ELISA serum levels of VEGF and asymmetric dimethylarginine (ADMA), as respective markers of angiogenesis and endothelial dysfunction. We included 235 unrelated subjects: 187 SSc patients and 48 controls. Higher concentrations of sENG (P = 0.002) and sVEGF (P < 0.0001) were found in SSc patients compared with controls whereas there was no difference for ADMA. In multivariate analysis, sENG levels were significantly increased in SSc patients with cutaneous ulcerations (P = 0.0003), positive for ACAs (P = 0.009) and with abnormal diffusing capacity for carbon monoxide divided by alveolar volume (P = 0.03). Soluble ENG levels negatively correlated with ADMA, but no relationship was found between sENG and sVEGF. This study shows increased values of sENG in a large SSc cohort and a relevant association with a vascular phenotype. The predictive value of the biomarker sENG and its potential role on cellular endothelial disturbances remain to be determined.

Storm sudden commencement events and the associated geomagnetically induced current risks to ground‐based systems at low‐latitude and midlatitude locations

Large impulsive geomagnetic field disturbances from auroral current systems have always been well understood as a concern for power grids in close proximity to these disturbance regions, predominantly at high‐latitude locations. Magnetospheric shocks (SSCs) due to large‐scale interplanetary pressure pulses are familiar from a geomagnetic disturbance perspective but have not been understood in the context as a potential driver for large geomagnetically induced currents (GICs). Observational evidence and analysis contained in this paper illustrate such events are capable of producing large geoelectric fields and associated GIC risks at any latitude, even equatorial locations. A large SSC disturbance on 24 March 1991 produced some of the largest GICs ever measured in the United States at midlatitude locations. The analysis methods and understanding of electromagnetic coupling processes at that time were unable to fully explain these observations. Electrojet‐driven disturbances common at high‐latitude locations during geomagnetic substorms cause large amplitude variations in locally observed B field, while SSC events are characterized as low‐amplitude B field disturbance events. Disturbance amplitude only accounts for part of the electromagnetic coupling process. The attribute of spectral content of the disturbance is equally important and heretofore had not been well understood and was not well measured unless high‐cadence observations were conducted. The deep‐earth ground conductivity also provides an important enabling role at higher frequencies. Deep‐earth ground response to geomagnetic field disturbances is highly frequency‐dependent. Therefore for nearly all ground conditions the higher the spectral content of the incident magnetic field disturbance, the higher the relative geoelectric field response.

Temperature effects on radiation damage to silicon detectors

Motivated by the large particle fluences anticipated for the SSC and LHC, we are performing a systematic study of radiation damage to silicon microstrip detectors. Here we report radiation effects on detectors cooled to 0°C (the proposed operating point for a large SSC silicon tracker) including leakage currents and change in depletion voltage. We also present results on the annealing behavior of the radiation damage. Finally, we report results of charge collection measurements of the damaged detectors made with an 241Am α source.

Φ-shaped magnet for a big detector on large accelerators

We have studied several magnet configurations for large SSC and LHC detectors. Taking into consideration the size restrictions of existing and planned experimental halls, we conclude that Φ-shaped magnets maximize the usable field volume for realistic configurations at minimum costs.

Pinealocyte subsurface cisterns I: Cytologieal aspects including three‐dimensional structure

Subsurface cisterns (ssc) in the pineal gland of Meriones unguiculatus have been characterized with transmission electron microscopy, freeze-fracture, morphometry, and three-dimensional reconstruction. Subsurface cisterns (which are observed only in pinealocytes and never in gliocytes) are cisterns of the endoplasmic reticulum (ER) approaching the plasmalemma at a distance of 15-20 nm. Freeze-fracture preparations show that except for some ribosomes at the cytoplasmic face, the cistern membranes as well as the related portions of the plasmalemma are free of special or specifically arranged particles or pores. All ssc have a lumen of 15-20 nm width and underlie 5.6% of the plasmalemma in a single layer; neither collapsed types nor stacks of ssc could be observed. As seen from reconstructions, large ssc are fenestrated and are situated preferentially in regions where the neighboring pinealocyte also bears large ssc. As a consequence, double-sided ssc, which can be observed in sections of (mostly large) ssc, are not a random phenomenon. In regions of the large ssc, adhering junctions are also concentrated. Tubules of 20-nm diameter link ssc with deeper parts of the ER, particularly with the perinuclear cistern and with the tubulo-cisternal network at the trans-side of the Golgi apparatus. Besides ssc proper, a lot of small endplates of ER-tubules are seen close to the plasmalemma. It is suggested that ssc form by the widening and fusing of such ER-tubules and decrease by retraction of ER-tubules from the cell surface.

On the Occurrence of Large SSC Amplitudes in the Horizontal Intensity of the Geomagnetic Field in Middle Latitudes Around Local Midnight

A study is made of the SSC amplitudes in H in relation to their local time of occurrence in the middle latitudes using data of 10 geomagnetic stations for the period 1953-60. It is found that (1) the greatest SSC amplitudes in H are recorded (in the summer months) around the local midnight (1 to 3 hours before or 1 to 3 hours afterthe local midnight), and (2) the minimum in SSC amplitudes in H occurs (in the winter months) during 18h-21h L. T. at the African stations and during 4h-10h L. T. (generally around 7h L. T.) at the other stations.The midnight maximum amplitude and the morning minimum amplitude are explained in terms of the ionospheric screening effect and precipitation of electrons into the auroral zone ionosphere on the night side of the earth from the outer Van Allen Belt at the time of the SSC.