SIRT3 Overexpression Ameliorates Asbestos-Induced Pulmonary Fibrosis, mt-DNA Damage, and Lung Fibrogenic Monocyte Recruitment

Alveolar epithelial cell (AEC) mitochondrial (mt) DNA damage and fibrotic monocyte-derived alveolar macrophages (Mo-AMs) are implicated in the pathobiology of pulmonary fibrosis. We showed that sirtuin 3 (SIRT3), a mitochondrial protein regulating cell fate and aging, is deficient in the AECs of idiopathic pulmonary fibrosis (IPF) patients and that asbestos- and bleomycin-induced lung fibrosis is augmented in Sirt3 knockout (Sirt3-/-) mice associated with AEC mtDNA damage and intrinsic apoptosis. We determined whether whole body transgenic SIRT3 overexpression (Sirt3Tg) protects mice from asbestos-induced pulmonary fibrosis by mitigating lung mtDNA damage and Mo-AM recruitment. Crocidolite asbestos (100 µg/50 µL) or control was instilled intratracheally in C57Bl6 (Wild-Type) mice or Sirt3Tg mice, and at 21 d lung fibrosis (histology, fibrosis score, Sircol assay) and lung Mo-AMs (flow cytometry) were assessed. Compared to controls, Sirt3Tg mice were protected from asbestos-induced pulmonary fibrosis and had diminished lung mtDNA damage and Mo-AM recruitment. Further, pharmacologic SIRT3 inducers (i.e., resveratrol, viniferin, and honokiol) each diminish oxidant-induced AEC mtDNA damage in vitro and, in the case of honokiol, protection occurs in a SIRT3-dependent manner. We reason that SIRT3 preservation of AEC mtDNA is a novel therapeutic focus for managing patients with IPF and other types of pulmonary fibrosis.

The lung microenvironment shapes a dysfunctional response of alveolar macrophages in aging

Alveolar macrophages orchestrate the response to viral infections. Age-related changes in these cells may underlie the differential severity of pneumonia in older patients. We performed an integrated analysis of single-cell RNA-Seq data that revealed homogenous age-related changes in the alveolar macrophage transcriptome in humans and mice. Using genetic lineage tracing with sequential injury, heterochronic adoptive transfer, and parabiosis, we found that the lung microenvironment drove an age-related resistance of alveolar macrophages to proliferation that persisted during influenza A viral infection. Ligand-receptor pair analysis localized these changes to the extracellular matrix, where hyaluronan was increased in aged animals and altered the proliferative response of bone marrow-derived macrophages to granulocyte macrophage colony-stimulating factor (GM-CSF). Our findings suggest that strategies targeting the aging lung microenvironment will be necessary to restore alveolar macrophage function in aging.

Single-Cell Transcriptomic Analysis of Human Lung Provides Insights into the Pathobiology of Pulmonary Fibrosis

Rationale: The contributions of diverse cell populations in the human lung to pulmonary fibrosis pathogenesis are poorly understood. Single-cell RNA sequencing can reveal changes within individual cell populations during pulmonary fibrosis that are important for disease pathogenesis. Objectives: To determine whether single-cell RNA sequencing can reveal disease-related heterogeneity within alveolar macrophages, epithelial cells, or other cell types in lung tissue from subjects with pulmonary fibrosis compared with control subjects. Methods: We performed single-cell RNA sequencing on lung tissue obtained from eight transplant donors and eight recipients with pulmonary fibrosis and on one bronchoscopic cryobiospy sample from a patient with idiopathic pulmonary fibrosis. We validated these data using in situ RNA hybridization, immunohistochemistry, and bulk RNA-sequencing on flow-sorted cells from 22 additional subjects. Measurements and Main Results: We identified a distinct, novel population of profibrotic alveolar macrophages exclusively in patients with fibrosis. Within epithelial cells, the expression of genes involved in Wnt secretion and response was restricted to nonoverlapping cells. We identified rare cell populations including airway stem cells and senescent cells emerging during pulmonary fibrosis. We developed a web-based tool to explore these data. Conclusions: We generated a single-cell atlas of pulmonary fibrosis. Using this atlas, we demonstrated heterogeneity within alveolar macrophages and epithelial cells from subjects with pulmonary fibrosis. These results support the feasibility of discovery-based approaches using next-generation sequencing technologies to identify signaling pathways for targeting in the development of personalized therapies for patients with pulmonary fibrosis.

Multidimensional Assessment of the Host Response in Mechanically Ventilated Patients with Suspected Pneumonia

Rationale: The identification of informative elements of the host response to infection may improve the diagnosis and management of bacterial pneumonia. Objectives: To determine whether the absence of alveolar neutrophilia can exclude bacterial pneumonia in critically ill patients with suspected infection and to test whether signatures of bacterial pneumonia can be identified in the alveolar macrophage transcriptome. Methods: We determined the test characteristics of alveolar neutrophilia for the diagnosis of bacterial pneumonia in three cohorts of mechanically ventilated patients. In one cohort, we also isolated macrophages from alveolar lavage fluid and used the transcriptome to identify signatures of bacterial pneumonia. Finally, we developed a humanized mouse model of Pseudomonas aeruginosa pneumonia to determine if pathogen-specific signatures can be identified in human alveolar macrophages. Measurements and Main Results: An alveolar neutrophil percentage less than 50% had a negative predictive value of greater than 90% for bacterial pneumonia in both the retrospective (n = 851) and validation cohorts (n = 76 and n = 79). A transcriptional signature of bacterial pneumonia was present in both resident and recruited macrophages. Gene signatures from both cell types identified patients with bacterial pneumonia with test characteristics similar to alveolar neutrophilia. Conclusions: The absence of alveolar neutrophilia has a high negative predictive value for bacterial pneumonia in critically ill patients with suspected infection. Macrophages can be isolated from alveolar lavage fluid obtained during routine care and used for RNA-Seq analysis. This novel approach may facilitate a longitudinal and multidimensional assessment of the host response to bacterial pneumonia.

Osteoprotegerin mediate RANK/RANKL signaling inhibition eases asthma inflammatory reaction by affecting the survival and function of dendritic cells

INTRODUCTION

Asthma is a chronic inflammatory, heterogeneous airway disease affecting millions of people around the world. Dendritic cells (DCs) are considered the most important antigen-presenting cell in asthma airway inflammatory reaction. But whether osteoprotegerin (OPG) mediate RANK/RANKL signaling inhibition influences asthma development by affecting the survival and function of DCs remains unclear. In this study, we assessed the effects of OPG on DCs and asthma.

MATERIAL AND METHODS

BALB/c mice immunized with ovalbumin (OVA) were challenged thrice with an aerosol of OVA every second day for eight days. Dexamethasone (1.0mg/kg) or OPG (50μg/kg) was administered intraperitoneally to OVA-immunized BALB/c mice on day 24 once a day for nine days. Mice were analyzed for effects of OPG on asthma, inflammatory cell infiltration and cytokine levels in lung tissue. The expression of RANK and β-actin was detected by Western Blot. DCs were isolated from mouse bone morrow. Cell survival was assessed by cell counting. The content of IL-12 was detected by ELISA.

RESULTS

Results showed that OVA increased the number of inflammatory factors in BALF, elevated lung inflammation scores in mice. OPG reversed the alterations induced by OVA in the asthmatic mice. OPG inhibited the survival and function of DC via inhibition of RANK/RANKL signaling.

CONCLUSIONS

This research proved inhibition of RANK/RANKL signaling by OPG could ease the inflammatory reaction in asthma, providing new evidence for the application of OPG on asthma.

Metformin Targets Mitochondrial Electron Transport to Reduce Air-Pollution-Induced Thrombosis

Urban particulate matter air pollution induces the release of pro-inflammatory cytokines including interleukin-6 (IL-6) from alveolar macrophages, resulting in an increase in thrombosis. Here, we report that metformin provides protection in this murine model. Treatment of mice with metformin or exposure of murine or human alveolar macrophages to metformin prevented the particulate matter-induced generation of complex III mitochondrial reactive oxygen species, which were necessary for the opening of calcium release-activated channels (CRAC) and release of IL-6. Targeted genetic deletion of electron transport or CRAC channels in alveolar macrophages in mice prevented particulate matter-induced acceleration of arterial thrombosis. These findings suggest metformin as a potential therapy to prevent some of the premature deaths attributable to air pollution exposure worldwide.

Influenza A Virus Infection Induces Muscle Wasting via IL-6 Regulation of the E3 Ubiquitin Ligase Atrogin-1

Muscle dysfunction is common in patients with adult respiratory distress syndrome and is associated with morbidity that can persist for years after discharge. In a mouse model of severe influenza A pneumonia, we found the proinflammatory cytokine IL-6 was necessary for the development of muscle dysfunction. Treatment with a Food and Drug Administration-approved Ab antagonist to the IL-6R (tocilizumab) attenuated the severity of influenza A-induced muscle dysfunction. In cultured myotubes, IL-6 promoted muscle degradation via JAK/STAT, FOXO3a, and atrogin-1 upregulation. Consistent with these findings, atrogin-1^+/- and atrogin-1^-/- mice had attenuated muscle dysfunction following influenza infection. Our data suggest that inflammatory endocrine signals originating from the injured lung activate signaling pathways in the muscle that induce dysfunction. Inhibiting these pathways may limit morbidity in patients with influenza A pneumonia and adult respiratory distress syndrome.

Monocyte-derived alveolar macrophages drive lung fibrosis and persist in the lung over the life span

Misharin et al. elucidate the fate and function of monocyte-derived alveolar macrophages during the course of pulmonary fibrosis. These cells persisted throughout the life span, were enriched for the expression of profibrotic genes, and their genetic ablation ameliorated development of pulmonary fibrosis.

Little is known about the relative importance of monocyte and tissue-resident macrophages in the development of lung fibrosis. We show that specific genetic deletion of monocyte-derived alveolar macrophages after their recruitment to the lung ameliorated lung fibrosis, whereas tissue-resident alveolar macrophages did not contribute to fibrosis. Using transcriptomic profiling of flow-sorted cells, we found that monocyte to alveolar macrophage differentiation unfolds continuously over the course of fibrosis and its resolution. During the fibrotic phase, monocyte-derived alveolar macrophages differ significantly from tissue-resident alveolar macrophages in their expression of profibrotic genes. A population of monocyte-derived alveolar macrophages persisted in the lung for one year after the resolution of fibrosis, where they became increasingly similar to tissue-resident alveolar macrophages. Human homologues of profibrotic genes expressed by mouse monocyte-derived alveolar macrophages during fibrosis were up-regulated in human alveolar macrophages from fibrotic compared with normal lungs. Our findings suggest that selectively targeting alveolar macrophage differentiation within the lung may ameliorate fibrosis without the adverse consequences associated with global monocyte or tissue-resident alveolar macrophage depletion.

'Orbital volume restoration rate after orbital fracture'; a CT-based orbital volume measurement for evaluation of orbital wall reconstructive effect

PurposeTo evaluate the effect of orbital reconstruction and factors related to the effect of orbital reconstruction by assessing of orbital volume using orbital computed tomography (CT) in cases of orbital wall fracture.MethodsIn this retrospective study, 68 patients with isolated blowout fractures were evaluated. The volumes of orbits and herniated orbital tissues were determined by CT scans using a three-dimensional reconstruction technique (the Eclipse Treatment Planning System). Orbital CT was performed preoperatively, immediately after surgery, and at final follow ups (minimum of 6 months). We evaluated the reconstructive effect of surgery making a new formula, 'orbital volume reconstruction rate' from orbital volume differences between fractured and contralateral orbits before surgery, immediately after surgery, and at final follow up.ResultsMean volume of fractured orbits before surgery was 23.01±2.60 cm³ and that of contralateral orbits was 21.31±2.50 cm³ (P=0.005). Mean volume of the fractured orbits immediately after surgery was 21.29±2.42 cm³, and that of the contralateral orbits was 21.33±2.52 cm³ (P=0.921). Mean volume of fractured orbits at final follow up was 21.50±2.44 cm³, and that of contralateral orbits was 21.32±2.50 cm³ (P=0.668). The mean orbital volume reconstruction rate was 100.47% immediately after surgery and 99.17% at final follow up. No significant difference in orbital volume reconstruction rate was observed with respect to fracture site or orbital implant type. Patients that underwent operation within 14 days of trauma had a better reconstruction rate at final follow up than patients who underwent operation over 14 days after trauma (P=0.039).ConclusionComputer-based measurements of orbital fracture volume can be used to evaluate the reconstructive effect of orbital implants and provide useful quantitative information. Significant reduction of orbital volume is observed immediately after orbital wall reconstruction surgery and the reconstruction effect is maintained for more than minimum 6 months. Patients that undergo surgery within 14 days of trauma has better reconstruction rates at final follow up, which supports the need for early surgery.

Mitochondrial catalase overexpressed transgenic mice are protected against lung fibrosis in part via preventing alveolar epithelial cell mitochondrial DNA damage

RATIONALE

Alveolar epithelial cell (AEC) injury and mitochondrial dysfunction are important in the development of lung fibrosis. Our group has shown that in the asbestos exposed lung, the generation of mitochondrial reactive oxygen species (ROS) in AEC mediate mitochondrial DNA (mtDNA) damage and apoptosis which are necessary for lung fibrosis. These data suggest that mitochondrial-targeted antioxidants should ameliorate asbestos-induced lung.

OBJECTIVE

To determine whether transgenic mice that express mitochondrial-targeted catalase (MCAT) have reduced lung fibrosis following exposure to asbestos or bleomycin and, if so, whether this occurs in association with reduced AEC mtDNA damage and apoptosis.

METHODS

Crocidolite asbestos (100µg/50µL), TiO₂ (negative control), bleomycin (0.025 units/50µL), or PBS was instilled intratracheally in 8-10 week-old wild-type (WT - C57Bl/6J) or MCAT mice. The lungs were harvested at 21d. Lung fibrosis was quantified by collagen levels (Sircol) and lung fibrosis scores. AEC apoptosis was assessed by cleaved caspase-3 (CC-3)/Surfactant protein C (SFTPC) immunohistochemistry (IHC) and semi-quantitative analysis. AEC (primary AT2 cells from WT and MCAT mice and MLE-12 cells) mtDNA damage was assessed by a quantitative PCR-based assay, apoptosis was assessed by DNA fragmentation, and ROS production was assessed by a Mito-Sox assay.

RESULTS

Compared to WT, crocidolite-exposed MCAT mice exhibit reduced pulmonary fibrosis as measured by lung collagen levels and lung fibrosis score. The protective effects in MCAT mice were accompanied by reduced AEC mtDNA damage and apoptosis. Similar findings were noted following bleomycin exposure. Euk-134, a mitochondrial SOD/catalase mimetic, attenuated MLE-12 cell DNA damage and apoptosis. Finally, compared to WT, asbestos-induced MCAT AT2 cell ROS production was reduced.

CONCLUSIONS

Our finding that MCAT mice have reduced pulmonary fibrosis, AEC mtDNA damage and apoptosis following exposure to asbestos or bleomycin suggests an important role for AEC mitochondrial H₂O₂-induced mtDNA damage in promoting lung fibrosis. We reason that strategies aimed at limiting AEC mtDNA damage arising from excess mitochondrial H₂O₂ production may be a novel therapeutic target for mitigating pulmonary fibrosis.

Modified tarsotomy for the treatment of severe cicatricial entropion

PurposeTo analyze the efficacy of modified tarsotomy for the management of severe cicatricial entropion.MethodsTwenty-seven eyelids of 18 patients who underwent modified tarsotomy between March 2011 and July 2013 were retrospectively assessed. The data collected included patient demographics, etiology of cicatricial entropion, and surgical history. Outcome measures included surgical success rate, preoperative and postoperative eyelid position, and surgery-related complications.ResultsMean follow-up time was 13.2 months (range, 6-25.4 months), and the success rate was 81.8% (22 of 27 eyelids). Complications included eyelid margin notching (n=1) and blepharoptosis secondary to avascular necrosis of the distal marginal fragment (n=1), both were corrected by minor surgical intervention.ConclusionsThe study findings suggest modified tarsotomy is effective for the correction of severe cicatricial entropion.

Lung-specific loss of α3 laminin worsens bleomycin-induced pulmonary fibrosis

Laminins are heterotrimeric proteins that are secreted by the alveolar epithelium into the basement membrane, and their expression is altered in extracellular matrices from patients with pulmonary fibrosis. In a small number of patients with pulmonary fibrosis, we found that the normal basement membrane distribution of the α3 laminin subunit was lost in fibrotic regions of the lung. To determine if these changes play a causal role in the development of fibrosis, we generated mice lacking the α3 laminin subunit specifically in the lung epithelium by crossing mice expressing Cre recombinase driven by the surfactant protein C promoter (SPC-Cre) with mice expressing floxed alleles encoding the α3 laminin gene (Lama3(fl/fl)). These mice exhibited no developmental abnormalities in the lungs up to 6 months of age, but, compared with control mice, had worsened mortality, increased inflammation, and increased fibrosis after the intratracheal administration of bleomycin. Similarly, the severity of fibrosis induced by an adenovirus encoding an active form of transforming growth factor-β was worse in mice deficient in α3 laminin in the lung. Taken together, our results suggest that the loss of α3 laminin in the lung epithelium does not affect lung development, but plays a causal role in the development of fibrosis in response to bleomycin or adenovirally delivered transforming growth factor-β. Thus, we speculate that the loss of the normal basement membrane organization of α3 laminin that we observe in fibrotic regions from the lungs of patients with pulmonary fibrosis contributes to their disease progression.

Morphological characteristics and clinical manifestations of orbital emphysema caused by isolated medial orbital wall fractures

PURPOSE

To investigate the morphological characteristics and clinical manifestations of orbital emphysema in patients with isolated medial orbital wall fractures.

METHODS

This was a retrospective observational case series of 348 orbits of 348 patients with isolated medial orbital wall fractures. Medical charts were reviewed, and computed tomographic (CT) images were examined to determine the morphological characteristics of orbital emphysema.

RESULTS

Orbital emphysema was detected in 70 orbits (20.1%). Large and communited type fracture was related with the presence of orbital emphysema (P<0.05). Orbital air pockets were detected in medial or superior extraconal orbital segment in all cases with orbital emphysema. Swollen eyelid with crepitus (90.0%) and supraduction limitation (31.4%) were developed with orbital emphysema. All cases with supraduction limitation accompanied with superior extraconal orbital emphysema and superior rectus muscle deviation, and these eyes were fully recovered with conservative management without surgery.

CONCLUSIONS

Orbital emphysema can be a cause of ocular motility restriction following orbital wall fracture. If supraduction limitation is noted with isolated medial wall fracture and superior orbital emphysema with superior rectus muscle deviation is detected by CT scan, conservative management can be a good choice for spontaneous recovery delaying the surgery.

Modeling human influenza infection in the laboratory

Influenza is the leading cause of death from an infectious cause. Because of its clinical importance, many investigators use animal models to understand the biologic mechanisms of influenza A virus replication, the immune response to the virus, and the efficacy of novel therapies. This review will focus on the biosafety, biosecurity, and ethical concerns that must be considered in pursuing influenza research, in addition to focusing on the two animal models - mice and ferrets - most frequently used by researchers as models of human influenza infection.

Mcl-1 is a key regulator of the ovarian reserve

A majority of ovarian follicles are lost to natural death, but the disruption of factors involved in maintenance of the oocyte pool results in a further untimely follicular depletion known as premature ovarian failure. The anti-apoptotic B-cell lymphoma 2 (Bcl-2) family member myeloid cell leukemia-1 (MCL-1) has a pro-survival role in various cell types; however, its contribution to oocyte survival is unconfirmed. We present a phenotypic characterization of oocytes deficient in Mcl-1, and establish its role in maintenance of the primordial follicle (PMF) pool, growing oocyte survival and oocyte quality. Mcl-1 depletion resulted in the premature exhaustion of the ovarian reserve, characterized by early PMF loss because of activation of apoptosis. The increasingly diminished surviving cohort of growing oocytes displayed elevated markers of autophagy and mitochondrial dysfunction. Mcl-1-deficient ovulated oocytes demonstrated an increased susceptibility to cellular fragmentation with activation of the apoptotic cascade. Concomitant deletion of the pro-apoptotic Bcl-2 member Bcl-2-associated X protein (Bax) rescued the PMF phenotype and ovulated oocyte death, but did not prevent the mitochondrial dysfunction associated with Mcl-1 deficiency and could not rescue long-term breeding performance. We thus recognize MCL-1 as the essential survival factor required for conservation of the postnatal PMF pool, growing follicle survival and effective oocyte mitochondrial function.

Adipocytes contribute to resistance of human melanoma cells to chemotherapy and targeted therapy

Epidemiological evidence has linked the development and progression of several cancers including melanoma with obesity. However, whether obesity impinges on responses of cancer cells to treatment remains less understood. Here we report that human adipocytes contribute to resistance of melanoma cells to various therapeutic agents. Exposure to media from adipocyte cultures (adipocyte media) increased cell proliferation and reduced sensitivity of melanoma cells to apoptosis induced by diverse chemotherapeutic drugs, including the DNA-damaging drug cisplatin, the microtubuletargeting agent docetaxel, and the histone deacetylase inhibitor SAHA. This was associated with increased activation of PI3K/Akt and MEK/ERK signaling, and was attenuated by a PI3K or MEK inhibitor. The effect of adipocyte media on melanoma cells was, at least in part, due to the interaction between the adipokine leptin and its long form receptor OB-Rb, in that immunodepletion of leptin in adipocyte media or siRNA knockdown of OB-Rb in melanoma cells reversed the increase in Akt and ERK activation, enhancement in cell proliferation, and importantly, protection of melanoma cells against the drugs. In support, recombinant leptin partially recapitulated the effect of adipocyte media on melanoma cells. Of note, OB-Rb was increased on the surface of melanoma cells compared to melanocytes, whereas leptin short form receptors appeared to be suppressed post-transcriptionally, suggesting that OB-Rb was selectively upregulated in melanoma cells. Collectively, these results indicate that adipocytes contribute to the resistance of melanoma cells to chemotherapeutic drugs and agents targeting the PI3K/Akt and MEK/ERK pathways, and suggest that inhibition of the leptin/ OB-Rb system may be useful to improve the efficacy of multiple therapeutic approaches in the treatment of melanoma.

Phase transitions, phase coexistence, and piezoelectric switching behavior in highly strained BiFeO(3) films

Highly strained BiFeO3 films transition into a true tetragonal state at 430 °C but remain polar to much higher temperatures (∼800 °C). Piezoelectric switching is only possible up to 300 °C, i.e., at temperatures for which strain stabilizes the stripe-like coexistence of multiple polymorphs.

Older Asian Americans and Pacific Islanders with Activities of Daily Living (ADL) limitations: immigration and other factors associated with institutionalization

This study determined the national prevalence and profile of Asian Americans with Activities of Daily Living (ADL) limitations and identified factors associated with institutionalization. Data were obtained from 2006 American Community Survey, which replaced the long-form of the US Census. The data are nationally representative of both institutionalized and community-dwelling older adults. Respondents were Vietnamese (n = 203), Korean (n = 131), Japanese (n = 193), Filipino (n = 309), Asian Indian (n = 169), Chinese (n = 404), Hawaiian/Pacific Islander (n = 54), and non-Hispanic whites (n = 55,040) aged 55 and over who all had ADL limitations. The prevalence of institutionalized among those with ADL limitations varies substantially from 4.7% of Asian Indians to 18.8% of Korean Americans with ADL limitations. Every AAPI group had a lower prevalence of institutionalization than disabled Non-Hispanic whites older adults (23.8%) (p < 0.001). After adjustment for socio-demographic characteristics, Asian Indians, Vietnamese, Japanese, Filipino, and Chinese had significantly lower odds of institutionalization than non-Hispanic whites (OR = 0.29, 0.31, 0.58, 0.51, 0.70, respectively). When the sample was restricted to AAPIs, the odds of institutionalization were higher among those who were older, unmarried, cognitively impaired and those who spoke English at home. This variation suggests that aggregating data across the AAPI groups obscures meaningful differences among these subpopulations and substantial inter-group differences may have important implications in the long-term care setting.

Activation of the calcineurin/NFAT signalling cascade starts early in human hypertrophic myocardium

Cardiac hypertrophy is an independent risk factor for heart failure. Recent studies on gene regulation of proteins have involved intracellular Ca2+ homeostasis. The Ca2+-sensitive phosphatase, calcineurin, is one potential regulator of the hypertrophic response, so we aimed to investigate the calcineurin-dependent signal pathway at different stages of hypertrophy in human myocardium. We found the calcineurin pathway to be significantly activated in hypertrophic compared with non-hypertrophic myocardium as demonstrated by increased calcineurin activity and expression of calcineurin A-beta and B, and GATA-4, and a shift of phosphorylated cytoplasmic NFAT-3 into the nucleus as dephosphorylated nuclear NFAT-3. There was a tendency for these changes to be more pronounced in the decompensated compared with the compensated hypertrophic myocardium. The present study provides evidence for significant activation of the Ca2+-triggered calcineurin pathway in hypertrophic humans. Already present in compensated hypertrophy it showed a tendency to a further increase following transition to decompensated hypertrophy.

Interactions of insulin-like growth factors and estradiol in rat pituitary gonadotrophs

Insulin-like growth factors are involved in the regulation of gonadotropin secretion. Insulin-like growth factor I (IGF-I) has an augmenting effect on gonodotropin-releasing hormone (GnRH)-induced luteinizing hormone (LH) release from female rat gonadotrophs that is facilitated by estradiol. To identify the underlying mechanisms, we investigated whether IGF-I influences total LH pool and the production of intracellular inositol phosphate. In another series of experiments we tested whether IGF-II and estradiol affect LH release of gonadotrophs. Pituitary cells were incubated with 100 pM IGF-I and/or 100 pM estradiol for 24 h. They were stimulated, partially in the presence of Wortmannin, an inhibitor of phosphoinositide 3-kinase, with 330 pM GnRH for 3 h. Subsequently, total LH pool (released and remaining hormone content in lysed cells) in cultures was measured. Intracellular inositol trisphosphate of alphaT3-1 cells, a gonadotrope cell line, treated with estradiol and IGF-I as described before and stimulated with 100 nM GnRH for 15 min was analyzed by ion exchange chromatography. To determine the interaction of IGF-II and estradiol on GnRH-stimulated LH secretion, cells were treated with increasing concentrations of IGF-II (0.05 pM-10 nM) and 100 pM estradiol. IGF-I significantly increased the accumulation of inositol trisphosphate in basal and GnRH-stimulated cells. IGF-I, estradiol, or their combinations did not change total LH pool, although they enhanced LH secretion. Wortmannin abolished the positive effects of IGF-I and estradiol on LH secretion. IGF-II alone increased basal, but not GnRH-induced LH secretion at low concentrations (0.05 pM). Additional estradiol treatment further increased basal, but not GnRH-induced LH secretion. In conclusion, our results suggest that increased LH secretion from female anterior pituitary cells after IGF treatment is due to the amplification of early signal transduction steps rather than changes in LH pool. The inositol trisphosphate signaling pathway is involved in the regulation of LH secretion from gonadotrophs treated with IGF-I. It is not likely that IGF-II plays an important role in the regulation of gonadotropin secretion.

Observer error in grading performance status in cancer patients

To assess the Karnofsky Performance Status (KPS) scale and the Eastern Cooperative Oncology Group (ECOG) scale with respect to interobserver reliability and interobserver difference between the two scales, 100 consecutive patients in a medical oncology unit were assessed using both scales, which were then given to three independent raters and also to the patients themselves. There was a high level of agreement between most paired assessors. There were three exceptions, which were the RMO/patient and nurse/patient pairs on the KPS scale and the RMO/patient pair on the ECOG scale. The level of agreement was better on the ECOG scale. For individual raters there is no statistical difference between the ECOG and Karnofsky scales. There was good agreement between all raters for both scales. Interobserver variability was less using the ECOG scale. We conclude that either scale could be used with good interobserver reliability. The ECOG scale minimises differences between observers.

Action of organophosphate anticholinesterases on the three conformational states of nicotinic receptor

Organophosphate and other ligands were examined for binding on the membrane-bond nicotinic receptor at three conformational states. Soman (pinacolyl methylphosphonofluoridate), sarin (isopropyl methylphosphonofluoridate, tabun (ethyl N-dimethylphosphoramidocyanidate) and phencyclidine did not show any effect on the binding of [25I]alpha-cobrotoxin to the nicotinic receptor. However, VX, O-ethyl-S-(2-diisopropylaminoethyl) methylphosphonothiolate, at concentrations higher than 10 umol/L exhibited profound inhibition on the equilibrium binding rates in a concentration-dependent manner. Agonist nicotine and antagonist d-tubocurarine also showed significant inhibitions.

Increased calcium levels alter cellular and molecular events in wound healing

Surgical morbidity is dictated directly by wound healing. We have studied the effects of elevated calcium levels using cultured keratinocytes in vitro on two of the rate-limiting steps of wound healing, chemotaxis (directed migration) and adhesion. We found that the increased calcium (10 mmol/L) significantly inhibited both keratinocyte chemotaxis and adhesion (p less than 0.05). The calcium effect on adhesion could be partially reversed by pretreatment with the calcium channel blocker verapamil. Based on these data, an animal model was formulated in which topical calcium (5 mmol/L/day) was added to linear incision wounds. This resulted in significantly (p less than 0.05) delayed wound contraction characteristic of a chronic or impaired wound. Wound contraction depends on the presence of fibroblasts that synthesize collagen. The chronic wound was characterized by increased collagenase activity (p less than 0.05) but little alteration in collagen I synthesis. The addition of verapamil to these chronic wounds resulted in improved wound closure. These studies define the molecular and cellular events occurring as a result of the addition of elevated levels of calcium both in vitro and in vivo. Calcium may play a key role in the pathogenesis of chronic wounds.

Recognition and receptor-mediated uptake of phosphorylated high mannose-type oligosaccharides by cultured human fibroblasts

The intracellular transport of newly synthesized lysosomal hydrolases to lysosomes requires the presence of one or more phosphorylated high mannose-type oligosaccharides per enzyme. A receptor that mediates mannose-6-PO4-specific uptake of lysosomal enzymes is expressed on the surface of fibroblasts and presumably accounts for the intracellular transport of newly synthesized enzymes to the lysosome. In this study, we examined the internalization of lysosomal enzyme-derived phosphorylated oligosaccharides by cultured human fibroblasts. Oligosaccharides of known specific activity bearing a single phosphate in monoester linkage were internalized with Kuptake of 3.2 X 10(-7) M, whereas oligosaccharides bearing two phosphates in monoester linkage were internalized with a Kuptake of 3.9 X 10(-8) M. Thus, phosphorylated high mannose-type oligosaccharides appear to be the minimal structure required for recognition and uptake by the fibroblast receptor. The finding that the Kuptake for monophosphorylated oligosaccharides is 100-fold less than the reported Ki for mannose-6-phosphate indicates that the fibroblast phosphomannosyl receptor contains a binding site that recognizes features of the oligosaccharide in addition to mannose-6-phosphate.