Clinical risk factors in patients with interstitial lung disease associated with anti-MDA5 autoantibodies

INTRODUCTION

The anti-MDA5-associated autoimmune disease represents a poorly understood entity. The study's objectives were to describe a cohort of interstitial lung disease (ILD) patients who were positive for anti-MDA5 autoantibody and identify clinical risk factors associated with survival.

METHODS

This single-center cohort study included ILD patients positive for anti-MDA5 autoantibody. Baseline clinical features were registered, and survival analysis was performed to identify risk factors associated with worse survival.

RESULTS

Fifty-three ILD-MDA5 positive patients were included; twelve died during follow-up due to rapidly progressive interstitial lung disease (RP-ILD). Dermatological signs of anti-MDA5 (Gottron papules, Gottron sign, palmar papules, V-neck sign, facial dermatomyositis rashes, and skin ulcers) were strongly associated with death secondary to RP-ILD (HR: 3.7, 95% CI: 1.02-13.35). Patients with dermatological signs were younger, had higher anti-MDA5 autoantibodies titers, more frequent inflammatory patterns in HRCT evaluation, and less fibrosis extent in HRCT.

CONCLUSION

Dermatological manifestation in ILD patients to anti-MDA5 autoantibodies are associated with RP-ILD and short-term fatal outcomes. Dermatological signs may identify a subgroup of ILD-positive to anti-MDA5 patients with a high risk of RP-ILD.

Enhanced Activity of NLRP3 Inflammasome in the Lung of Patients with Anti-Synthetase Syndrome

Anti-synthetase syndrome (ASSD) is an autoimmune disorder characterized by inflammatory interstitial lung disease (ILD). The main objective of this work was to quantify the concentrations of cytokines and molecules associated with inflammasome activation in bronchoalveolar lavage (BAL) of patients with ASSD and a comparison group of systemic sclerosis (SSc) patients. Cytokines and lactate dehydrogenase (LDH) were determined using the concentrated BAL protein. The activity of caspase-1 and concentration of NLRP3 with the protein purified from the cell pellet in each group of patients. We found higher caspase-1 levels in ASSD vs. SSc, 1.25 RFU vs. 0.75 RFU p = 0.003, and LDH levels at 0.15 OD vs. 0.09 OD p < 0.001. A significant difference was observed in molecules associated with inflammasome activation, IL-18: 1.42 pg/mL vs. 0.87 pg/mL p = 0.02 and IFN-γ: 0.9 pg/mL vs. 0.86 pg/mL, p = 0.01. A positive correlation was found between caspase-1 and LDH in the patients with ASSD Rho 0.58 (p = 0.008) but not in the SSc group. In patients with ASSD, greater caspase-1 and higher LDH activity were observed in BAL, suggesting cell death due to pyroptosis and activation of the inflammasome pathway.

Clinical spectrum time course in non-Asian patients positive for anti-MDA5 antibodies

OBJECTIVES

To define the clinical spectrum time-course and prognosis of non-Asian patients positive for anti-MDA5 antibodies.

METHODS

We conducted a multicentre, international, retrospective cohort study.

RESULTS

149 anti-MDA5 positive patients (median onset age 53 years, median disease duration 18 months), mainly females (100, 67%), were included. Dermatomyositis (64, 43%) and amyopathic dermatomyositis (47, 31%), were the main diagnosis; 15 patients (10%) were classified as interstitial pneumonia with autoimmune features (IPAF) and 7 (5%) as rheumatoid arthritis. The main clinical findings observed were myositis (84, 56%), interstitial lung disease (ILD) (108, 78%), skin lesions (111, 74%), and arthritis (76, 51%). The onset of these manifestations was not concomitant in 74 cases (50%). Of note, 32 (21.5%) patients were admitted to the intensive care unit for rapidly progressive-ILD, which occurred in median 2 months from lung involvement detection, in the majority of cases (28, 19%) despite previous immunosuppressive treatment. One-third of patients (47, 32% each) was ANA and anti-ENA antibodies negative and a similar percentage was anti-Ro52 kDa antibodies positive. Non-specific interstitial pneumonia (65, 60%), organising pneumonia (23, 21%), and usual interstitial pneumonia-like pattern (14, 13%) were the main ILD patterns observed. Twenty-six patients died (17%), 19 (13%) had a rapidly progressive-ILD.

CONCLUSIONS

The clinical spectrum of the anti-MDA5 antibodies-related disease is heterogeneous. Rapidly-progressive ILD deeply impacts the prognosis also in non-Asian patients, occurring early during the disease course. Anti-MDA5 antibody positivity should be considered even when baseline autoimmune screening is negative, anti-Ro52 kDa antibodies are positive, and radiology findings show a NSIP pattern.

MUC5B promoter variant rs35705950 and rheumatoid arthritis associated interstitial lung disease survival and progression

BACKGROUND

The major risk factor for idiopathic pulmonary fibrosis (IPF), MUC5B rs35705950, was found to be associated with rheumatoid arthritis-associated interstitial lung disease (RA-ILD). Whilst the MUC5B rs35705950 T risk allele has been associated with better survival in IPF, its impact on RA-ILD prognosis remains to be determined. Our objective was to explore the influence of MUC5B rs35705950 on survival and progression in RA-ILD.

METHODS

Through an international retrospective observational study, patients with RA-ILD were genotyped for the MUC5B rs35705950 variant and consecutive pulmonary function tests (PFTs) findings were collected. Longitudinal data up to a 10-year follow-up were considered and analyzed using mixed regression models. Proportional hazards and joint proportional hazards models were used to analyze the association of baseline and longitudinal variables with lung transplant-free survival. Significant progression of RA-ILD was defined as at least an absolute or relative 10% decline of forced vital capacity at 2 years from baseline.

RESULTS

Out of 321 registered patients, 261 were included in the study: 139 women (53.3%), median age at RA-ILD diagnosis 65 years (interquartile range [IQR] 57 to 71), 151 ever smokers (59.2%). Median follow-up was 3.5 years (IQR 1.3 to 6.6). Mortality rate was 32% (95%CI 19 to 42) at 10 years. The MUC5B rs35705950 variant did not impact lung transplant-free survival (HR for the T risk allele carriers=1.26; 95%CI 0.61 to 2.62; P=0.53). Decline in pulmonary function at 2 years was not influenced by MUC5B rs35705950 (OR=0.95; 95%CI 0.44 to 2.05; P=0.89), irrespective of the HRCT pattern.

CONCLUSION

In this study, the MUC5B rs35705950 promoter variant did not influence transplant- free survival or decline in pulmonary function in patients with RA-ILD.

Methotrexate and rheumatoid arthritis associated interstitial lung disease

QUESTION ADDRESSED BY THE STUDY

Methotrexate (MTX) is a key anchor drug for rheumatoid arthritis (RA) management. Fibrotic interstitial lung disease (ILD) is a common complication of RA. Whether MTX exposure increases the risk of ILD in patients with RA is disputed. We aimed to evaluate the association of prior MTX use with development of RA-ILD.

METHODS

Through a case-control study design with discovery and international replication samples, we examined the association of MTX exposure with ILD in 410 patients with chronic fibrotic ILD associated with RA (RA-ILD) and 673 patients with RA without ILD. Estimates were pooled over the different samples using meta-analysis techniques.

RESULTS

Analysis of the discovery sample revealed an inverse relationship between MTX exposure and RA-ILD (adjusted OR 0.46, 95% CI 0.24-0.90; p=0.022), which was confirmed in the replication samples (pooled adjusted OR 0.39, 95% CI 0.19-0.79; p=0.009). The combined estimate using both the derivation and validation samples revealed an adjusted OR of 0.43 (95% CI 0.26-0.69; p=0.0006). MTX ever-users were less frequent among patients with RA-ILD compared to those without ILD, irrespective of chest high-resolution computed tomography pattern. In patients with RA-ILD, ILD detection was significantly delayed in MTX ever-users compared to never-users (11.4±10.4 years and 4.0±7.4 years, respectively; p<0.001).

ANSWER TO THE QUESTION

Our results suggest that MTX use is not associated with an increased risk of RA-ILD in patients with RA, and that ILD was detected later in MTX-treated patients.

The shearing stress of baseball-spontaneous coronary artery dissection in a male athlete

The following is a case report of an atypical presentation of spontaneous coronary artery disease. In this case, a male with risk factors, precipitated by an emotional stress, presented to the emergency room with atypical chest pain. Cardiac catheterization revealed tapering of the mid-left anterior descending artery, consistent with non-atherosclerotic spontaneous coronary artery disease. However due to repeat chest pain, a repeat cardiac catheterization was performed, revealing 100% occlusion of the mid-LAD. This case represents an atypical presentation of a pathology that is frequently missed, and underreported. This is important to discuss in order to increase awareness, as the management and follow up are actually conservative.

Determination of the phenotypic age in residents of Mexico City: effect of accelerated ageing on lung function and structure

INTRODUCTION

Phenotypic age better represents age-related biological dysregulation than chronological age. Recently, a multisystem-based ageing measure, which integrates chronological age and nine biomarkers, was proposed.

METHODS

Phenotypic age was determined in 774 residents of Mexico City over 60 years old and without respiratory problems. We arbitrarily classified as "accelerated" ageing, those showing >4 years compared with their chronological age, and "slowed" ageing, those with <4 years compared with chronological age. Demographic risk factors were analysed with structured questionnaires. Lung structure was evaluated by high-resolution computed tomography and functional competence was analysed by forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1), diffusion capacity of carbon monoxide (D LCO), and the 6-minute walk test (6MWT).

RESULTS

Overall, 13% of this cohort showed accelerated ageing, which was corroborated with four independent biomarkers of ageing, 42% had normal ageing and 46% had slowed ageing. Risk factors associated with accelerated ageing were male sex (OR 4.4, 95% CI 2.4-7.9; p<0.01), diabetes mellitus (OR 9.7, 95% CI 5.5-17.2; p<0.01), and long-term sleep duration (OR 2.9 95% CI 1.34-6.35, p<0.01). Among smokers, there was a slight but significant association with the number of pack-years. Subjects with accelerated ageing showed decreased FVC (p<0.0001), FEV1 (p<0.0001), D LCO (p<0.02) and walking distance in the 6MWT (p=0.0001). Slowed-ageing subjects presented less frequently with emphysematous lesions compared with those with accelerated ageing.

CONCLUSIONS

A small but significant proportion of residents of Mexico City age rapidly, which is associated with male sex, diabetes, and long-term sleep duration. They exhibit lower levels of lung function and develop emphysema more frequently.

Risk factors associated with the detection of pulmonary emphysema in older asymptomatic respiratory subjects

Background

Several lung structural and functional abnormalities may occur associated with aging, including emphysema. In this study, we evaluated the frequency and risk factors associated with emphysema in respiratory asymptomatic individuals enrolled in our Lung Aging Program. From a cohort of 687 subjects, we found by high-resolution computed tomography (HRCT) 29 individuals (4%) with emphysematous changes that were compared with 87 controls (3:1) randomly selected from the same cohort.

Methods

This was a transversal, observational, case-control study where we examined demographics and functional characteristics, as well as telomere length and serum Klotho concentration, two conditions that have been associated with aging and some aging-associated diseases including emphysema.

Results

Individuals with subclinical pulmonary emphysema were older (72 ± 9 versus 67 ± 6 years), and primarily smoker males with low body mass index. Despite that they were asymptomatic, two of them exhibited a decrease of forced expiratory volume in 1 s (FEV₁), with a lower FEV₁/FVC suggesting airway obstruction. Cigarette smoking (OR = 5.43, CI95% 1.8–16.7), family history of lung disease (OR = 4.32, CI95% 1.0–19.0) and lower body mass index (OR 7.22, CI95% 1.2–3.5) were risk factors for the development of lung emphysematous changes. No association was found with telomere length and Klotho serum concentration.

Conclusion

Our findings reveal that a small but important percentage of older people without respiratory symptoms, present pulmonary emphysema and indicate that smoking exposure and genetic background may contribute to etiological factors.

Anti-Aminoacyl Transfer-RNA-Synthetases (Anti-tRNA) Autoantibodies Associated with Interstitial Lung Disease: Pulmonary Disease Progression has a Persistent Elevation of the Th17 Cytokine Profile

Anti-tRNA autoantibodies are associated with interstitial lung disease (ILD), in at least two clinical scenarios: the anti-synthetase syndrome (ASSD) and interstitial pneumonia with autoimmune features (IPAF). Under pathological conditions, cytokines indicate the participating elements and the course of inflammatory phenomena. We aimed to quantify serum concentrations of different inflammatory cytokines profiles in patients with anti-tRNA associated ILD (anti-tRNA-ILD) and estimate the association between these and ILD improvement and progression. Serum levels of 18 cytokines from baseline and after six months of treatment of ILD patients’ positives to anti-tRNA were included in the current study. At six months, patients were classified as with or without ILD progression. A total of 39 patients were included (10 anti-Jo1, eight anti-PL7, 11 anti-PL12, and 10 anti-Ej). Three patients (7.6%) had ILD progression (progressors patients, PP) and showed statistically higher levels in IL-4, IL-10, IL-17A, IL-22, GM-CSF, IL-1β, IL-6, IL-12, IL-18, and TNF-α, compared to patients without disease progression (no progressors patients, NPP). IL-17A, IL-1β, and IL-6 (T-helper-lymphocyte (Th)17 inflammatory cytokine profile) were elevated and had a high discriminatory capacity in distinguishing ILD PP of those NPP at follow-up. Overall, there is an association between the cytokines of the Th17 inflammatory profile and the ASSD progression.

Influence of Antisynthetase Antibodies Specificities on Antisynthetase Syndrome Clinical Spectrum Time Course

Antisynthetase syndrome (ASSD) is a rare clinical condition that is characterized by the occurrence of a classic clinical triad, encompassing myositis, arthritis, and interstitial lung disease (ILD), along with specific autoantibodies that are addressed to different aminoacyl tRNA synthetases (ARS). Until now, it has been unknown whether the presence of a different ARS might affect the clinical presentation, evolution, and outcome of ASSD. In this study, we retrospectively recorded the time of onset, characteristics, clustering of triad findings, and survival of 828 ASSD patients (593 anti-Jo1, 95 anti-PL7, 84 anti-PL12, 38 anti-EJ, and 18 anti-OJ), referring to AENEAS (American and European NEtwork of Antisynthetase Syndrome) collaborative group’s cohort. Comparisons were performed first between all ARS cases and then, in the case of significance, while using anti-Jo1 positive patients as the reference group. The characteristics of triad findings were similar and the onset mainly began with a single triad finding in all groups despite some differences in overall prevalence. The “ex-novo” occurrence of triad findings was only reduced in the anti-PL12-positive cohort, however, it occurred in a clinically relevant percentage of patients (30%). Moreover, survival was not influenced by the underlying anti-aminoacyl tRNA synthetase antibodies’ positivity, which confirmed that antisynthetase syndrome is a heterogeneous condition and that antibody specificity only partially influences the clinical presentation and evolution of this condition.

Quantitative assessment of interstitial lung disease in Sjögren's syndrome

BACKGROUND

Interstitial lung disease (ILD) is a frequent manifestation of Sjögren's syndrome (SS), an autoimmune disease of salivary and lacrimal glands, and affects approximately 20% of patients. No clinical or serological features appear to be useful to predict its presence, severity or progression, and chest high-resolution computed tomography (CT) remains the gold standard for diagnosis. Semiquantitative CT (SQCT) based on visual assessment (Goh and Taouli scoring) can estimate ILD extent, although it is burdened by relevant intra- and interobserver variability. Quantitative chest CT (QCT) is a promising alternative modality to assess ILD severity.

AIM

To determine whether QCT assessment can identify extensive or limited lung disease in patients with SS and ILD.

METHODS

This multi-center, cross-sectional and retrospective study enrolled patients with SS and a chest CT scan. SQCT assessment was carried out in a blinded and centralized manner to calculate both Goh and Taouli scores. An operator-independent analysis of all CT scans with the open-source software platform Horos was used to evaluate the QCT indices. Patients were classified according to the extent of ILD and differences in QCT index distribution were investigated with non-parametric tests.

RESULTS

From a total of 102 consecutive patients with SS, the prevalence of ILD was 35.3% (36/102). There was a statistically significant difference in QCT index distribution between the SS with ILD and SS without ILD groups (p<0.001). Moreover, SS-ILD patients with ILD >20% (by Goh score) had a QCT index statistically different from those with limited ILD extent (p<0.001). Finally, QCT indices showed a moderate-to-good correlation with the Goh and Taouli scores (from 0.44 to 0.65; p<0.001).

CONCLUSIONS

QCT indices can identify patients with SS and ILD and discriminate those with lesser or greater lung disease.

Free will perceptions and psychiatric symptoms in patients diagnosed with schizophrenia

WHAT IS KNOWN ON THE SUBJECT?: Some research suggests that holding a free will perspective may offer mental health and physical health benefits. WHAT THIS PAPER ADDS TO EXISTING KNOWLEDGE?: This study is the first to examine links between free will perceptions and psychiatric symptoms in patients diagnosed with schizophrenia. WHAT ARE THE IMPLICATIONS FOR PRACTICE?: Study results suggest that helping people with a diagnosis of schizophrenia to recognize situations where they do have some freedom of choice over their actions and emotional reactions (free will) may assist them in improving their experiences and better managing their symptoms.

ABSTRACT

Introduction Some research indicates that having a strong sense that one possesses free will may be associated with better psychological and physical health. This study is the first to examine the relationship between free will perceptions and psychiatric symptoms in patients with a diagnosis of schizophrenia. Method Thirty-two participants were interviewed using the Brief Psychiatric Rating Scale to assess symptom severity and the Free Will Subscale of the Free Will and Determinism Scale to assess free will perceptions. Results As hypothesized, a negative association was found between free will perceptions and total symptom severity, though it appears that this was mainly accounted for by positive symptoms. A content analysis was also conducted to qualitatively examine how patients conceptualize the construct of free will and its role in coping with their own mental illness. Discussion Study results suggest that holding a free will perspective may mitigate psychiatric symptoms in patients with a diagnosis of schizophrenia. Thus, psychiatric nurses and other mental health clinicians may improve current treatments for schizophrenia by helping patients recognize situations where they do have some freedom of choice over their actions and emotional reactions (free will) to stressful life events.

Accelerated variant of idiopathic pulmonary fibrosis: clinical behavior and gene expression pattern

Background

Idiopathic pulmonary fibrosis (IPF) is characterized by the insidious onset of dyspnea or cough. However, a subset of patients has a short duration of symptoms with rapid progression to end-stage disease. In this study, we evaluated clinical and molecular features of “rapid” and “slow” progressors with IPF.

Methods and Findings

26 patients with <6 months of symptoms before first presentation [rapid progressors] and 88 patients with >24 months of symptoms [slow progressors] were studied. Survival was analyzed by the Kaplan-Meyer method and proportional hazard's model. Lung microarrays and tissue proteins were measured in a subset of patients. No differences were found in age, physiologic impairment and bronchoalveolar lavage (BAL) cellular profile. There were more males (OR = 6.5; CI:1.4-29.5; p = 0.006) and smokers (OR = 3.04; CI:1.1-8.3; p = 0.04) in the rapid progressors group. Survival from the beginning of symptoms was significantly reduced in rapid progressors (HR = 9.0; CI:4.48-18.3; p<0.0001) and there was a tendency for decreased survival from the time of diagnosis (HR = 1.5; CI:0.81-2.87; p = 0.18). We identified 437 differentially expressed genes. Lungs of rapid progressors overexpressed genes involved in morphogenesis, oxidative stress, migration/proliferation, and genes from fibroblasts/smooth muscle cells. Upregulation of two of these genes, adenosine-2B receptor and prominin-1/CD133, was validated by immunohistochemistry and were expressed by alveolar epithelial cells. BAL from rapid progressors showed a >2-fold increase of active matrix metalloproteinase-9, and induced a higher fibroblast migration compared with slow progressors and controls [238±98% versus 123±29% (p<0.05) and 30±17% (p<0.01)].

Conclusions/Significance

A subgroup of IPF patients, predominantly smoking males, display an accelerated clinical course and have a gene expression pattern that is different from those with slower progression and longer survival. These findings highlight the variability in the progression of IPF, and may explain, in part, the difficulty in obtaining significant and reproducible results in studies of therapeutic interventions in patients with IPF.

Airway-centered interstitial fibrosis: a distinct form of aggressive diffuse lung disease

We describe 12 patients with a form of interstitial lung disease characterized pathologically by small airway-centered interstitial fibrosis and metaplastic bronchiolar epithelium extending around and often linking fibrotic and sometimes heavily muscularized bronchioles. Clinically, patients presented with chronic cough and progressive dyspnea. One was a current light smoker and two were ex-smokers. In 8 patients, a history of possible inhalational exposures, including wood smoke, birds, cotton, pasture, chalk dust, agrochemical compounds, and cocaine use, was elicited. Pulmonary function tests showed moderate to severe physiologic abnormalities, in most instances indicating a restrictive lung disease with decreased peripheral flow rates. Chest radiographs revealed predominantly diffuse reticulonodular infiltrates in the central lung fields, with thickening of the bronchial walls and decreased lung volumes. Chest computed tomography demonstrated peribronchovascular fibrosis and interstitial thickening. Bronchoalveolar lavage showed a mild increase in lymphocytes in 4 subjects. Patients were treated with corticosteroids and bronchodilators. Follow-up data were available in 10 patients. In 5 patients, the disease progressed and 4 of them died. Two patients remained stable and 3 improved or healed. We propose that these findings represent a distinct airway-centered disease that mostly behaves as an interstitial lung disease and may exhibit a poor outcome.

Increased Surfactant Protein-A Levels in Patients With Newly Diagnosed Idiopathic Pulmonary Fibrosis

STUDY OBJECTIVES

To measure surfactant protein-A (SP-A) in the BAL of patients with idiopathic pulmonary fibrosis (IPF).

DESIGN

We examined SP-A in BAL and lung tissue of patients with IPF who met the stricter recommended criteria for IPF at the time of diagnosis and prior to the beginning of treatment.

PATIENTS

Twenty-six patients with IPF confirmed at biopsy and 22 patients with hypersensitivity pneumonitis (HP) were compared with 9 normal volunteers.

INTERVENTIONS

All patients were subjected to pulmonary function testing, BAL, and lung biopsy prior to the beginning of treatment.

MEASUREMENTS AND RESULTS

We measured SP-A in BAL fluids and performed SP-A immunohistochemistry on lung specimens. Lung tissues of patients with IPF showed extensive type II cell hyperplasia, usually containing greatly increased levels of immunoreactive SP-A. By enzyme-linked immunosorbent assay, we found a twofold increase over normal values in BAL SP-A without changes in total phospholipids. These data were in agreement with semiquantitative assessments of SP-A by protein immunoblotting and by Western blotting of sodium dodecyl sulfate gels. Patients with HP exhibited a threefold increase of BAL SP-A.

CONCLUSIONS

The reasons for the difference between our results and previously published reports describing decreased SP-A levels in IPF is not clear. It may relate to the stricter criteria for diagnosis, the absence of treatment prior to BAL, differences in the patient population, or to other methodologic differences.

Severe ethylene glycol ingestion treated without hemodialysis

Fomepizole (4-methylpyrazole, Antizol) is being increasingly used in the treatment of ethylene glycol toxicity in adults. Little experience exists with this drug, however, in the pediatric population. We present a case of ethylene glycol poisoning in a child where use of fomepizole averted intravenous ethanol infusion and hemodialysis, limited the duration of intensive care monitoring, and decreased the overall cost of treatment.

Localization of choline acetyltransferase in the developing and adult turtle retinas

Acetylcholine has important epigenetic roles in the developing retina. In this study, cells that expressed choline acetyltransferase (ChAT), the enzyme that synthesizes acetylcholine, were investigated in embryonic, postnatal, and adult turtle retinas by using immunofluorescence histochemistry. ChAT was present at stage 15 (S15) in cells near the vitreal surface. With the formation of the inner plexiform layer (IPL) at S18, ChAT-immunoreactive (-IR) cells were located in the inner nuclear layer (INL) and the ganglion cell layer (GCL). In the INL, presumed starburst amacrine cells were homogenous in appearance and formed a single row next to the IPL: This pattern was conserved until adulthood. In the GCL, however, there were multiple rows of ChAT-IR cells early in development, and this high density of labeled cells continued during the embryonic stages, until around birth. The high density of ChAT-IR cells in the GCL was due in part to a population of cells that expressed ChAT transiently. In postnatal stages and adult retinas, the presumed starburst amacrine ChAT-IR cells formed two mirror-like rows of homogenous cells on both borders of the IPL. Two cholinergic dendritic strata that were continuous with these cells were observed as early as S18, and their depths in the IPL were relatively stable throughout development. A third population of ChAT-IR cells was observed toward the middle of the INL around S25 and persisted into adulthood. Finally, cells in the outer nuclear layer (ONL) were ChAT-IR during the embryonic stages, were less immunoreactive during the postnatal stages, and were not immunoreactive in the adult retinas.

Noninvasive quantification of rCBF using positron emission tomography

This study proposes a new method for the pixel-by-pixel quantification of regional CBF (rCBF) with positron emission tomography and H(15)(2)O by using a reference tissue region. No arterial blood is required. Simulation studies revealed that the calculation of rCBF was fairly stable provided that the frame time was relatively short compared with total scan time. In practice, calculated CBF images correlated significantly with those obtained with the dynamic/integral method. Because the method accurately detects changes in CBF, it is particularly suitable for brain activation studies.

Validation of noninvasive quantification of rCBF compared with dynamic/integral method by using positron emission tomography and oxygen-15 labeled water

This study proposes a new solution for the quantification of rCBF pixel-by-pixel using PET and 15O-H2O. The method represents an application of weighted integration that used PET image only, requiring no input function of arterial blood. It generates the rCBF image quickly and automatically. Simulation studies revealed that the calculation of rCBF was fairly stable as long as a relatively shorter scan frame time and longer scan time were selected. Calculated images of actual PET study by this method correlated significantly with those identified by the dynamic/integral method. Because this procedure could detect whole brain CBF change between different studies as accurately as by the dynamic/integral method, this procedure may be the most suitable for brain activation studies.

Slope of serial glomerular filtration rate and the progression of diabetic glomerular disease

Glomerular function was evaluated longitudinally over a 24- to 48-month period in 18 patients with diabetic glomerular disease (DGD) manifested by proteinuria. GFR was determined by iothalamate clearance at 4-month intervals. The patients were divided into two groups: Group 1 (N = 9) had subnephrotic proteinuria and an initially normal GFR of 91 +/- 8 mL/min. Group 2 (N = 9) had nephrotic-range proteinuria, and initial GFR was reduced to 53 +/- 5 mL/min. Serial GFR fluctuated over time in Group 1, but no trend towards hypofiltration was evident. In contrast, GFR declined linearly in Group 2 at 1.1 +/- 0.3 mL/min per month. The transglomerular sieving of uncharged dextrans of graded size was analyzed and initially revealed a uniform reduction in glomerular pore density and an enhancement of shuntlike pores. Pore density was initially reduced by 80% and declined further after 24 months in nephrotic Group 2; corresponding pore density in subnephrotic Group 1 was reduced by half but remained constant. Renal biopsy of four members of Group 1 revealed a 22% prevalence of global glomerulosclerosis. Remaining open glomeruli exhibited hypertrophy, excessive extracellular matrix, and deformation of epithelial podocytes. The latter abnormality appeared to be the predominant determinant of lowered ultrafiltration capacity. It was inferred that trials of therapy to attenuate the progression of DGD should be initiated at a functional level similar to that in subnephrotic Group 1. Because GFR is unlikely to decline over a 2- to 4-yr period, it is suggested that such trials be extended for longer periods. Alternatively, morphometric analysis of serial renal biopsies may shorten the time needed to demonstrate effective renoprotection in DGD.