Deletion of calcineurin from GFAP-expressing astrocytes impairs excitability of cerebellar and hippocampal neurons through astroglial Na+/K+ ATPase

Astrocytes perform important housekeeping functions in the nervous system including maintenance of adequate neuronal excitability, although the regulatory mechanisms are currently poorly understood. The astrocytic Ca²⁺/calmodulin-activated phosphatase calcineurin (CaN) is implicated in the development of reactive gliosis and neuroinflammation, but its roles, including the control of neuronal excitability, in healthy brain is unknown. We have generated a mouse line with conditional knockout (KO) of CaN B1 (CaNB1) in glial fibrillary acidic protein-expressing astrocytes (a stroglial c alcin eurin KO [ACN-KO]). Here, we report that postnatal and astrocyte-specific ablation of CaNB1 did not alter normal growth and development as well as adult neurogenesis. Yet, we found that specific deletion of astrocytic CaN selectively impairs intrinsic neuronal excitability in hippocampal CA1 pyramidal neurons and cerebellar granule cells (CGCs). This impairment was associated with a decrease in after hyperpolarization in CGC, while passive properties were unchanged, suggesting impairment of K⁺ homeostasis. Indeed, blockade of Na⁺/K⁺-ATPase (NKA) with ouabain phenocopied the electrophysiological alterations observed in ACN-KO CGCs. In addition, NKA activity was significantly lower in cerebellar and hippocampal lysates and in pure astrocytic cultures from ACN-KO mice. While no changes were found in protein levels, NKA activity was inhibited by the specific CaN inhibitor FK506 in both cerebellar lysates and primary astroglia from control mice, suggesting that CaN directly modulates NKA activity and in this manner controls neuronal excitability. In summary, our data provide formal evidence for the notion that astroglia is fundamental for controlling basic neuronal functions and place CaN center-stage as an astrocytic Ca²⁺-sensitive switch.     

Genomic instability in the epidermis induced by atomic bomb (A‐bomb) radiation

BACKGROUND:

Radiation etiology is suggested in the occurrence of basal cell carcinoma (BCC) of the skin among atomic bomb (A‐bomb) survivors. Any genotoxicity, including ionizing radiation, can induce a DNA damage response (DDR), leading to genomic instability (GIN), which allows the accumulation of mutations during tumorigenesis. In this study, the authors evaluated the presence of GIN in the epidermis of survivors as a late effect of A‐bomb radiation.

METHODS:

In total, 146 BCCs, including 23 cases arising from nonexposed skin, were identified in survivors from 1968 to 1999. The incidence rate (IR) of BCC was calculated with stratification by distance in kilometers from the hypocenter (≤1.5 km, 1.6‐2.9 km, and ≥3 km). Nineteen epidermal samples surrounding BCC at the nonexposed sites were collected and tested for p53 binding protein 1 (53BP1) expression with immunofluorescence. 53BP1 rapidly forms nuclear foci at the sites of DNA double strand breaks (DSBs). Because 1 manifestation of GIN is the induction of endogenous DSBs, the level of 53BP1‐focus formation (DDR type) can be considered as a marker for GIN.

RESULTS:

The incidence rate of BCC increased significantly as exposure distance approached the hypocenter. Of the 7 epidermal samples from the proximal group (≤1.5 km), 5 samples predominantly expressed DDR and an abnormal type of 53BP1 expression. In contrast, 4 of 5 samples from the distal group (≥3 km) and all samples from the control group predominantly expressed the stable type of 53BP1 expression in the epidermis.

CONCLUSIONS:

The current results demonstrated the endogenous activation of DDR in the epidermis surrounding BCC in the proximal group, suggesting the presence of a GIN in the survivors as a late effect of A‐bomb radiation, which may indicate a predisposition to cancer. Cancer 2009. © 2009 American Cancer Society.     

Pyogenic Vertebral Osteomyelitis after Acute Bacterial Prostatitis: A Case Report

A case of pyogenic vertebral osteomyelitis after acute bacterial prostatitis in a 78-year-old man is reported. The rarity and subtle clinical presentation of this condition, and the delayed appearance of radiologic signs of progression to destructive osteomyelitis, contributed to a significant delay in diagnosis. An arterial blood culture positive for bacterial growth during the episode of acute prostatitis suggested that bacteremia might result from hematogenous spread of the infection to the vertebral column via the venous system. Since intensive antimicrobial therapy proved ineffective, debridement of the first and second lumbar vertebral bodies, and anterior spinal fusion from the twelfth thoracic to the third lumbar vertebrae were performed. The patient's high fever and severe lumbago subsided immediately after the surgery. The possibility of development to pyogenic vertebral osteomyelitis should be kept in mind when treating a serious genitourinary tract infection.     

Successful treatment of idiopathic pure red cell aplasia with antithymocyte globulin]

An 18-year-old woman was admitted to our hospital because of severe anemia on October 16, 1999. Laboratory data included hemoglobin 3.5 g/dl, reticulocytes 2,200/microliter, WBC 3,500/microliter, and Plt 38.5 x 10(4)/microliter. Bone marrow aspiration showed a normocellular marrow with severe erythroid hypoplasia, suggesting a diagnosis of pure red cell aplasia. Methylprednisolone pulse therapy was started on October 20, but there was no response. Administration of cyclosporine A (CyA; 400-450 mg) was begun on November 1, but again there was no response. Antithymocyte globulin (ATG; 800 mg/day for 5 days, 15 mg/kg) was started from December 1 in addition to prednisolone (60 mg/day) and CyA (450 mg/day). On day 7 of ATG therapy, the reticulocyte count began to increase, and reached a peak of 32.6 x 10(4)/microliter on day 20. The patient's hemoglobin level started to increase on day 13, and reached 8.5 g/dl on day 27. A complete response has been maintained up to the time of writing, and the hemoglobin level was 11.9 g/dl on December 14, 2000. This is the first detailed Japanese case report of successful treatment of pure red cell aplasia using ATG.     

Stereoisomers of glutathione: preparation and enzymatic reactivities.

We synthesized a series of stereoisomers of glutathione (GSH) and glutathione disulfide (GSSG) by the solid-phase method. These peptides were used to examine their reactivities with enzymes acting on glutathione. The glutathione reductase of yeast acted only on LL-GSSG. Glutathione S-transferase catalyzed the conjugation of 1-chloro-2,4-dinitrobenzene with LL-GSH and DL-GSH (Km (mM): for LL-GSH, 0.035; and for DL-GSH, 0.62), but the DD- and LD-diastereomers were inert. gamma-Glutamyl transpeptidase catalyzed the transfer of gamma-glutamyl moiety of LL-GSH and DL-GSH to taurine forming gamma-glutamyl taurine and cysteinyl taurine (Km (mM): for LL-GSH, 0.336; and for DL-GSH, 0.628), but the other diastereomers were not the substrates. The occurrence of L-cysteinyl residue in the tripeptides is required for the glutathione analogue to be a substrate of the enzymes.     

Clinical study of bronchial inhalation challenge in summer-type hypersensitivity pneumonitis induced by Trichosporon cutaneum]

To evaluate the methods and criteria of judgement for the bronchial antigen inhalation challenge test, the test was performed with culture filtrate antigen of serotype I and II of Trichosporon cutaneum in 18 patients with summer-type hypersensitivity pneumonitis from 15 families. The quantity of 15 mg of culture filtrate antigen was adequate, and had no side effects. In the tests, 17 of 18 patients showed a positive reaction to both or either, serotype of antigen. In 36 performances of inhalation, there were 21 positive reactions and 15 negative reactions. According to the criteria of judgment for inhalation challenge test, the positive response rates of observation items were 75% for symptoms and signs, and 51% for laboratory data. Items with a high positive rate were cough, crepitant rales, and decrease of PaO2. On the other hand, low positive rates were observed for decrease of DLco, VC and positive CRP. Items with both high sensitivity and high specificity were cough, crepitant rales and decrease of PaO2. The low positive rate of decreased DLco was due to insufficient improvement before inhalation challenge. It was concluded that our methods and criteria of judgment for bronchial inhalation challenge test are useful.     

High-dose granulocyte-colony stimulating factor promotes neointimal hyperplasia in the early phase and inhibits neointimal hyperplasia in the late phase after vascular injury

BACKGROUND: Granulocyte-colony stimulating factor (G-CSF) affects injured arteries through early endothelialization. Some reports, however, have cautioned that the restenosis rate may increase after G-CSF injection. In the present study, high-dose G-CSF was administered to mice with vascular injury to clarify its effect. METHODS AND RESULTS: Mice were received daily subcutaneous injections of saline or a high dose (300 microg/kg) of G-CSF for 5 days after vascular injury. In the FACS analysis, CD34-/Sca-1-positive progenitor cells were more abundant in the G-CSF group (p<0.05). Neointimal hyperplasia was more evident in the G-CSF group at 1 week (p<0.05), whereas at 4 weeks it was more evident in the control group (p<0.01). TUNEL-positive cells in the arterial wall were more numerous in the G-CSF group at day 1 (p<0.01). CD34-positive cells were observed in the G-CSF group at 1 week. Re-endothelialization appeared earlier in the G-CSF group (at 4 weeks; p<0.01). An increased number of 1A4-positive smooth muscle cells were found in bone marrow cell culture treated with G-CSF. CONCLUSION: High-dose G-CSF induced neointimal proliferation through excessive inflammation and bone marrow cell mobilization in the early phase. In the late phase, however, it induced early re-endothelialization and thereby inhibited neointimal hyperplasia.     

Effects of pulmonary rehabilitation in patients with pulmonary tuberculosis sequelae]

Pulmonary rehabilitation was evaluated for a mean period of 3.9 weeks in 37 inpatients with pulmonary tuberculosis sequelae. The rehabilitation program consisted of relaxation, breathing retraining, exercise training, respiratory muscle training and instruction. Significant improvement was shown in VC (n = 37) on average from 1.48 l to 1.59 l, in FEV1.0 (n = 37) from 0.93 l to 1.02 l, in PaO2 (n = 35) from 67.1 Torr to 72.4 Torr, in 6-minute walking distance (n = 29) from 303 m to 339 m, in Pimax (n = 17) from 38.5 cmH2O to 47.5 cmH2O, in activity (n = 23) from 19.6 points to 22.5 points, in dyspnea (n = 22) from 18.4 points to 22.5 points and in QOL (n = 25) from 39.0 points to 44.2 points. The effects of pulmonary rehabilitation did not depend on past thoracic surgery for tuberculosis, pattern of ventilatory impairment, findings of chest radiography, or degree of insufficiency. These data suggest that pulmonary rehabilitation is of benefit for improving pulmonary function, exercise tolerance, symptoms and QOL in patients with pulmonary tuberculosis sequelae.     

The effect of valsartan on regression of left ventricular hypertrophy in type 2 diabetic patients

AIM: The aim of the present study was to examine the effects of an angiotensin II receptor antagonist, valsartan, on echocardiographically proven left ventricular hypertrophy (LVH) in patients with type 2 diabetes. METHODS: Outpatients with type 2 diabetes mellitus were recruited at Niigata University Hospital. The left ventricular mass index (LVMI) was calculated by echocardiography. LVH was considered to be present if the LVMI was > 131 g/m(2) in males and > 100 g/m(2) in females. Patients with LVH received a low dose (40 mg/day) of valsartan for 12 months. This low dose had no clinical effect on blood pressure. RESULTS: Of the 38 patients who entered the study, 14 (36.8%) had LVH. After only 6 months of valsartan therapy, the mean LVMI decreased significantly, from 126.5 +/- 27.8 to 119.0 +/- 23.5 g/m(2) (p < 0.01 vs. baseline). Also, a significant decrease was observed after 12 months (116.5 +/- 30.9 g/m(2), p < 0.05 vs. baseline). Compared to baseline, there were no significant differences after treatment in body mass index, glycosylated haemoglobin (HbA(1c)), systolic blood pressure and diastolic blood pressure. CONCLUSIONS: In type 2 diabetic patients with LVH, treatment with a low dose of valsartan, an angiotensin II receptor antagonist, for 12 months, reduced LVMI, with no reduction in systemic blood pressure. This drug may be safely administered to type 2 diabetic patients with LVH. The long-term risk-reduction effects will have to be evaluated in further trials.