Ca2+ transients in astrocyte fine processes occur via Ca2+ influx in the adult mouse hippocampus

Astrocytes display complex morphologies with an array of fine extensions extending from the soma and the primary thick processes. Until the use of genetically encoded calcium indicators (GECIs) selectively expressed in astrocytes, Ca²⁺ signaling was only examined in soma and thick primary processes of astrocytes where Ca²⁺‐sensitive fluorescent dyes could be imaged. GECI imaging in astrocytes revealed a previously unsuspected pattern of spontaneous Ca²⁺ transients in fine processes that has not been observed without chronic expression of GECIs, raising potential concerns about the effects of GECI expression. Here, we perform two‐photon imaging of Ca²⁺ transients in adult CA1 hippocampal astrocytes using a new single‐cell patch‐loading strategy to image Ca²⁺‐sensitive fluorescent dyes in the cytoplasm of fine processes. We observed that astrocyte fine processes exhibited a high frequency of spontaneous Ca²⁺ transients whereas astrocyte soma rarely showed spontaneous Ca²⁺ oscillations similar to previous reports using GECIs. We exploited this new approach to show these signals were independent of neuronal spiking, metabotropic glutamate receptor (mGluR) activity, TRPA1 channels, and L‐ or T‐type voltage‐gated calcium channels. Removal of extracellular Ca²⁺ almost completely and reversibly abolished the spontaneous signals while IP₃R2 KO mice also exhibited spontaneous and compartmentalized signals, suggesting they rely on influx of extracellular Ca²⁺. The Ca²⁺ influx dependency of the spontaneous signals in patch‐loaded astrocytes was also observed in astrocytes expressing GCaMP3, further highlighting the presence of Ca²⁺ influx pathways in astrocytes. The mechanisms underlying these localized Ca²⁺ signals are critical for understanding how astrocytes regulate important functions in the adult brain. GLIA 2016;64:2093–2103     

Cancellous bone formation response to simulated resistance training during disuse is blunted by concurrent alendronate treatment

The purpose of this study was to assess the effectiveness of simulated resistance training (SRT) exercise combined with alendronate (ALEN) in mitigating or preventing disuse‐associated losses in cancellous bone microarchitecture and formation. Sixty male Sprague‐Dawley rats (6 months old) were randomly assigned to either cage control (CC), hind limb unloading (HU), HU plus either ALEN (HU + ALEN), SRT (HU + SRT), or a combination of ALEN and SRT (HU + SRT/ALEN) for 28 days. HU + SRT and HU + SRT/ALEN rats were anesthetized and subjected to muscle contractions once every 3 days during HU (four sets of five repetitions, 1000 ms isometric + 1000 ms eccentric). Additionally, HU + ALEN and HU + SRT/ALEN rats received 10 µg/kg of body weight of ALEN three times per week. HU reduced cancellous bone‐formation rate (BFR) by 80%, with no effect of ALEN treatment (?85% versus CC). SRT during HU significantly increased cancellous BFR by 123% versus CC, whereas HU + SRT/ALEN inhibited the anabolic effect of SRT (?70% versus HU + SRT). SRT increased bone volume and trabecular thickness by 19% and 9%, respectively, compared with CC. Additionally, osteoid surface (OS/BS) was significantly greater in HU + SRT rats versus CC (+32%). Adding ALEN to SRT during HU reduced Oc.S/BS (?75%), Ob.S/BS (?72%), OS/BS (?61%), and serum TRACP5b (?36%) versus CC. SRT and ALEN each independently suppressed a nearly twofold increase in adipocyte number evidenced with HU and inhibited increases in osteocyte apoptosis. These results demonstrate the anabolic effect of a low volume of high‐intensity muscle contractions during disuse and suggest that both bone resorption and bone formation are suppressed when SRT is combined with bisphosphonate treatment. © 2011 American Society for Bone and Mineral Research     

Treatment of recurrent ovarian cancer: a retrospective analysis of women treated with single-agent carboplatin originally treated with carboplatin and paclitaxel. The Memorial Sloan-Kettering Cancer Center experience

OBJECTIVE: There is no standard treatment for recurrent epithelial ovarian cancer (EOC). As there are no curative options, many oncologists choose to treat women who recur with carboplatin, particularly if they are deemed to have platinum-sensitive disease. However, particularly in the era of platinum-taxane treatment as primary therapy, the utility of this treatment has not been established, nor is it clear whether the results of single-agent treatment are equivalent to that of combination therapy. We sought to determine the outcomes for patients with platinum-sensitive EOC who were treated with carboplatin-taxane therapy and received single-agent carboplatin (C) as second chemotherapy. In addition, we sought to compare these results to the outcomes in women who received carboplatin and paclitaxel (C + T) at first relapse. PATIENTS AND METHODS: We identified 24 patients using our electronic institutional database with a histologically confirmed diagnosis of ovarian cancer that had a complete response to platinum-paclitaxel chemotherapy, relapsed greater than 6 months after treatment, and received single-agent carboplatin as second-line chemotherapy. We performed a subsequent comparison between a subgroup of this cohort and one that met the same inclusion criteria but received C + T at relapse between January 1998 and December 2000. RESULTS: Eighteen patients were evaluable for response, and all were available for analysis of survival end points. For evaluable patients, the overall response rate was 39% (complete, 11%; partial, 28%). Twenty-two percent had stable disease. Six (25%) patients experienced a hypersensitivity reaction, including 1 who required hospitalization. The median overall survival was 22 months. The 2-year overall survival rate was 49%. Stratification by treatment-free interval (TFI) showed a 25% for a TFI between 6 and 12 months and 43% for a TFI > 12 months. When a subgroup of these women (18/24) was compared to a cohort that received C + T (29), the combination was associated with a higher complete and overall response rate, 7 and 36% for C versus 45 and 71% for C + T (P = 0.02). The overall survival in women who received C was 26 months versus 42 months in the women who received C + T (P < 0.02). CONCLUSION: Carboplatin as a single agent is effective therapy for recurrent ovarian cancer in women who recur following treatment with carboplatin and paclitaxel, and the treatment-free interval predicts response to single-agent carboplatin. However, our secondary analysis suggests that carboplatin and paclitaxel may produce a higher response rate and a survival benefit compared to C alone. This supports the conclusions of ICON4, which recently reported both overall and progression-free survival benefits with C + T over C in women with platinum-sensitive recurrent disease.     

Ease of use of two autoinjectors in patients with multiple sclerosis treated with interferon beta-1a subcutaneously three times weekly: results of the randomized,crossover REDEFINE study

Background: For interferon beta-1a subcutaneously three times weekly (IFN β-1a SC tiw), administration options include manually injected prefilled syringes; a preassembled, single-use autoinjector; and a reusable autoinjector. This study evaluated patient-perceived ease of use of two injection devices.

Research design and methods: REDEFINE, a Phase IV, multicenter crossover study, randomized patients with multiple sclerosis and ≥5 weeks’ IFN β-1a 44 μg SC tiw use to 4 weeks using a single-use autoinjector, then 4 weeks using a reusable autoinjector, or vice versa. The primary endpoint was the proportion rating each ‘easy’ or ‘very easy’, with/without regard to previous device experience.

Results: Of 97 randomized patients, 29 had most recent experience with manual injection; 23 with single-use autoinjector; and 45 with reusable autoinjector. 68.4% found using the single-use autoinjector very easy or easy, versus 77.9% for the reusable device (difference ?9.5%; p = 0.200). 40.0% versus 29.5% found the respective devices very easy (difference 10.5%; p = 0.203).

Conclusions: Most patients found both autoinjectors easy or very easy to use. Having two viable options may help accommodate patient preferences. Ease of administration and patient satisfaction relates to adherence; satisfied patients may more likely be adherent.

Trial registration: The trial is registered at ClinicalTrials.gov (CT.gov identifier: NCT02019550).     

The Incidence of Oropharyngeal Dysphagia in Infants With GERD‐Like Symptoms

Background: Symptoms of infantile gastroesophageal reflux disease (GERD) may overlap with oropharyngeal dysphagia, but the evaluation and treatment of these conditions vary greatly. In this investigation, the incidence of oropharyngeal dysphagia in infants with GERD‐like symptoms is determined. Materials and Methods: A retrospective chart review was performed on infants referred to a pediatric gastroenterology clinic for GERD‐like symptoms. A feeding screen was performed in all infants. Standardized bedside swallow evaluation and modified barium swallow (MBS) studies were then performed when clinically indicated. A similarly aged cohort of normal participants also underwent a standard bedside swallow evaluation for group comparison. Results: Study population included 67 infants. A swallow evaluation was recommended in 39 of 67 infants with abnormalities noted in all. Swallowing abnormalities were more frequent and clustered in infants with GERD‐like symptoms vs controls. MBS was abnormal in 16 of 17 qualifying infants. Characteristics of at‐risk infants included extreme prematurity, developmental delay, or symptoms refractory to antireflux medications. Conclusion: Oropharyngeal dysphagia is prominent in infants with GERD‐like symptoms.