Defective glycosylation of calsequestrin in heart failure

OBJECTIVE: Levels of Ca2+ regulatory proteins have been extensively analyzed in cardiomyopathies as possible indices of change in sarcoplasmic reticulum (SR) structure and function. Measures of calsequestrin (CSQ), however, a critical protein component of the Ca2+ release complex in junctional sarcoplasmic reticulum, have provided little or no evidence of underlying dysfunction. We previously reported that calsequestrin isolated from heart tissue exists in a variety of glycoforms and phosphoforms reflecting mannose trimming of N-linked glycans and phosphorylation and dephosphorylation on protein kinase CK2-sensitive sites. METHODS: Here, we tested whether the distribution of molecular forms changes in heart failure (HF) reflecting possible remodeling of diseased tissue. Canine hearts were paced (220 beats/min) for 6-8 weeks to induce heart failure. Calsequestrin was purified from heart failure and sham-operated (control) treated canine ventricles and analyzed by electrospray mass spectrometry. RESULTS: The results showed striking changes in the mass distribution of calsequestrin molecules present in tissue from heart failure (five animals) compared with control (five animals). In heart failure, calsequestrin contained glycan structures that were uncharacteristic of normal junctional sarcoplasmic reticulum, consistent with altered metabolism or altered trafficking through secretory compartments. Glycoforms containing Man8,9, expected for a phenotype less muscle-like, were more than doubled in heart failure hearts, and molecules were also phosphorylated to a higher level. CONCLUSIONS: These data reveal in tachycardia-induced heart failure a new and potentially important change in the mannose content of calsequestrin glycans, perhaps indicative of defective junctional SR trafficking and Ca2+ release complex assembly.     

The Effect and Safety of the Antithrombotic Therapies in Patients with Atrial Fibrillation and CHADS2 Score 1

Anticoagulation in CHADS₂ Score 1 . Background: The revised ACC/AHA/ESC 2006 guideline recommends either aspirin or warfarin for the prevention of ischemic stroke in patients with atrial fibrillation (AF) in CHADS₂ score 1. We hypothesized that warfarin is superior to aspirin therapy for the prevention of stroke without increasing bleeding complication in AF patients with CHADS₂ score 1. Methods and Results: Among 1,502 patients (mean 62.4 ± 13.8 years old, male 65.4%) who were treated for nonvalvular AF without previous stroke, the number of patients with CHADS₂ score 1 was 422 (62.9 ± 10.7 years old, male 290 [68.7%]) and their antithrombotic therapies were as follows: warfarin (n = 143), aspirin (n = 124), other antiplatelet (n = 45), and no antithrombosis (none: n = 110). We reviewed the incidences of ischemic stroke, mortality, and bleeding complications during the follow‐up period. Results were: (1) during 22.3 ± 17.8 months of follow‐up, the incidence of ischemic stroke was significantly lower in warfarin (6 patients, 4.2%, mean international normalized ratio [INR] 2.0 ± 0.5 IU) than in aspirin (16 patients, 12.9%, P = 0.008) than none (23 patients, 20.9%, P < 0.001) without differences in all‐cause mortality. (2) The incidence of major bleeding (decrease in hemoglobin ≥2 g/dL, requiring hospitalization or red blood cell transfusion ≥2 pints) was not different between warfarin (2.1%) and aspirin (0.8%, P = NS), but minor bleeding was more common in warfarin (10.5%) than in aspirin (2.4%, P = 0.007). Conclusion: In AF patients with CHADS₂ score 1, warfarin was better to prevent ischemic stroke than aspirin without increasing the incidence of major bleeding complications. However, the incidence of minor bleeding was higher in the warfarin group than the aspirin group. (J Cardiovasc Electrophysiol, Vol. 21, pp. 501‐507, May 2010)     

Endocrine mediators of seasonal growth in gilthead sea bream (Sparus aurata): the growth hormone and somatolactin paradigm

Regulation of somatolactin (SL) and the somatotropic axis was examined year-around at three different stocking times (spring, summer, and autumn) in a Mediterranean fish, the gilthead sea bream (Sparus aurata). The overall timing of plasma growth hormone (GH) increase was similar among trials (late spring-early summer), but the range of variation year-around was different and followed changes in food intake. Total plasma insulin-like growth factor-I primarily followed changes on growth rates, and a close positive correlation between IGF-I and thermal-unit growth coefficient (TGC) was found irrespective of fish stocking time. Thus, the activation of the somatotropic axis preceded always warm growth spurts, whereas the rise of SL in concurrence with low plasma cortisol levels was found at late autumn. This up-regulation of circulating SL titres preceded the winter inhibition of feeding, and it was more severe in big fish (spring and summer stocking times) than in small fish (autumn stocking time), growing with a relative high efficiency during the cold season despite of a severe hypertriglyceridemia and a high hepatosomatic index. These new insights provide good evidence for a different timing of GH and SL increases, and it is likely that the dominant role of SL in energy homeostasis is to be a mediator of the adaptation to fasting after replenishment of body fat stores, whereas GH and IGF-I are perceived as growth-promoting signals in times of food intake and increasing temperature and day-length.     

Disruption of Sur2-containing K(ATP) channels enhances insulin-stimulated glucose uptake in skeletal muscle

ATP-sensitive potassium channels (K(ATP)) are involved in a diverse array of physiologic functions including protection of tissue against ischemic insult, regulation of vascular tone, and modulation of insulin secretion. To improve our understanding of the role of K(ATP) in these processes, we used a gene-targeting strategy to generate mice with a disruption in the muscle-specific K(ATP) regulatory subunit, SUR2. Insertional mutagenesis of the Sur2 locus generated homozygous null (Sur2(-/-)) mice and heterozygote (Sur2(+/-)) mice that are viable and phenotypically similar to their wild-type littermates to 6 weeks of age despite, respectively, half or no SUR2 mRNA expression or channel activity in skeletal muscle or heart. Sur2(-/-) animals had lower fasting and fed serum glucose, exhibited improved glucose tolerance during a glucose tolerance test, and demonstrated a more rapid and severe hypoglycemia after administration of insulin. Enhanced glucose use was also observed during in vivo hyperinsulinemic euglycemic clamp studies during which Sur2(-/-) mice required a greater glucose infusion rate to maintain a target blood glucose level. Enhanced insulin action was intrinsic to the skeletal muscle, as in vitro insulin-stimulated glucose transport was 1.5-fold greater in Sur2(-/-) muscle than in wild type. Thus, membrane excitability and K(ATP) activity, to our knowledge, seem to be new components of the insulin-stimulated glucose uptake mechanism, suggesting possible future therapeutic approaches for individuals suffering from diabetes mellitus.     

Helicobacter pylori acquistion of metronidazole resistance by natural transformation in vitro

AIM: To study whether Helicobacter pylori is naturally transformable.METHODS: Transformation was performed in BHI broth supplemented with horse serum and yeast extract. Genomic DNA extracted from a metronidazole resistant H.pylori strain was added to H. pylori broth culture. The mixture was incubated at microaerophilic atmosphere. The DNA-treated cells were plated on blood agar containing 8 mg/L metronidazole to select for transformants. Sterile distilled water was used as a negative DNA control. The DNA profiles of transformants were compared with that of their parent strains by randomly amplified polymorphic DNA (RAPD) fingerprinting.RESULTS: Transformation of H. pylori with DNA from a metronidazole resistant strain as a marker was demonstrated. Out of the 12 strains of H. pylori tested, 9 (75%) strains were found to be transformable. The transformation frequencies ranged from 3.4 × 10^-6 to 2.4 × 10^-4. By RAPD, DNA fingerprints of the transformants and their parent strains showed no change in DNA profiles though transformants were all resistant to metronidazole as compared with their metronidazole-sensitive parent strains.CONCLUSION: Helicobacter pylori is naturally transformable which might be one of the ways that H. pylori develops resistance to metronidazole.     

胰岛素瘤相关蛋白-2高表达对胰岛细胞增殖的影响

目的:探讨1型糖尿病自身抗原胰岛素瘤相关蛋白-2(IA鄄2)高表达对胰岛细胞系RIN5F细胞增殖、生长周期和细胞凋亡的影响。方法:利用分子克隆技术构建IA鄄2真核表达载体,转染RIN5F细胞后筛选稳定高表达IA鄄2的细胞系,采用3鄄(4,5鄄二甲基)鄄5鄄(3鄄羧甲基苯环)鄄2鄄(4鄄硫基苯)鄄2H鄄四唑盐复合物(MTS)检测法确定细胞增殖速率,运用流式细胞术检测细胞生长周期和细胞凋亡水平。结果:IA鄄2高表达细胞增殖速率显著低于载体对照组细胞(P<0.05)。IA鄄2高表达细胞的细胞凋亡数显著高于载体对照组细胞(P<0.01)。IA鄄2高表达细胞中位于S期的细胞比率显著增加,而G2/M期的细胞比率减少(P<0.05)。结论:IA鄄2在胰岛细胞内高表达可抑制胰岛细胞的增殖,促进细胞凋亡,在G2鄄M期细胞生长阻滞。     

Twelve-year follow up of a randomized prospective trial comparing bacillus Calmette-Guerin and epirubicin as adjuvant therapy in superficial bladder cancer

AIM: To compare bacillus Calmette-Guerin (BCG) with epirubicin in adjuvant therapy of superficial bladder transitional cell carcinoma, with respect to recurrence, progression and survival. Prognostic factors are also evaluated. METHODS: Between October 1991 and September 1999, all patients harboring superficial bladder cancers (Ta or T1) with any of the relevant criteria (stage>a, grade>1, size>1 cm, multiple or recurrent tumors), after complete transurethral resection were randomized to receive either 81 mg Connaught strain BCG or 50 mg epirubicin. Patients with recurrences were eligible to crossover, even repeatedly, until progression. Recurrence, progression and survival were analyzed in relation to initial treatment, patient characteristics and tumor characteristics. RESULTS: There were 209 patients included in the study, 149 men and 60 women. The mean age was 69.9 years (range, 24-92). The BCG group consisted of 102 patients and the epirubicin group contained 107 patients. Final analysis was made at a median follow up of 23, 47 and 61 months for recurrence, progression and survival, respectively. The 10-year Kaplan-Meier estimates for recurrence-free, progression-free and disease-specific survival were 61%, 78% and 80%, respectively, for the BCG group. The corresponding figures were 32%, 74% and 92%, respectively, for the epirubicin group. Time to recurrence differed significantly between two treatment groups (P=0.0004). Multiplicity increased the risk of recurrence, while grading influenced recurrence, progression and disease specific survival. CONCLUSIONS: Bacillus Calmette-Guerin prolonged time to recurrence when compared with epirubicin. Grading was shown to be a universal prognostic factor for recurrence, progression and disease specific survival.     

Mesenteric cyst. A review

The mesenteric cyst is a tumor of multiple origins, that undoubtedly presents with greater frequency than that referred in published series. Nevertheless, it continues to be a rare entity. Due to absence of characteristic signs and symptoms, diagnosis is only made once these lesions have reached a size, sufficiently large to be palpable or when they cause compression on organs or neighboring structures. The cyst can present with chronic manifestations such as diffuse abdominal pain imprecisely located but associated with palpable mass, or due to complications of the cyst or due to compression of adjacent structures. Diagnosis is confirmed by imaging studies, such as the different ultrasound modalities, computed tomography (CT) scan, and magnetic resonance imaging (MRI). A differential diagnosis must be made to exclude other intra-abdominal or retro-peritoneal tumors. Optimum treatment is extirpation of the cyst. On occasion it is also necessary to remove the adjacent organ due to the impossibility of enucleating cyst. marsupialization of the cyst or drainage into peritoneal cavity, have high incidence of recurrence. Surgical treatment can be carried out by minimal invasion techniques.