Dysphagia as the Sole Manifestation of Bilateral Strokes

Dysphagia can be caused by a host of factors, most of which are structural or functional. However, despite extensive evaluations, a certain number of patients have unexplained dysphagia. We present an extremely unusual case whereby a patient with an acute left hemispheric cerebral vascular accident presents with dysphagia as his sole complaint and after extensive neurological, gastroenterological, and radiographic examinations is found to have cricopharyngeal dysfunction. The etiology of this defect was not at all clinically apparent and, ultimately, magnetic resonance imaging (MRI) was performed which revealed a chronic infarction of the right frontal lobe and a smaller acute infarction in the same location of the left. This case demonstrates that swallowing disorders may be the sole presentation of stroke and that, if extensive evaluations of such patients fail to yield an etiology, one must strongly consider MRI as a tool for diagnosis, even if a CT scan is negative.     

Accuracy of dual-energy radiographic absorptiometry of the lumbar spine: cadaver study

Dual-energy radiographic absorptiometry (DRA) was used to measure the bone mineral content and area density of lumbar vertebrae (L2-L3) in 11 cadavers. These data were subsequently compared with measured ash content and density. Excellent correlation was obtained between bone mineral content measured with DRA and ash weight (r = .963, P less than .0001). The accuracy error in determining mineral content in lumbar vertebrae with DRA was about 9%. In addition, strong correlation was observed between bone mineral density measured with DRA and ash density (r = .881, P less than .0001).     

Annexin V for flow cytometric detection of phosphatidylserine expression on B cells undergoing apoptosis

Apoptosis, or programmed cell death, is a general mechanism for removal of unwanted cells from the immune system. It is characterized by chromatin condensation, a reduction in cell volume, and endonuclease cleavage of DNA into oligonucleosomal length fragments. Apoptosis is also accompanied by a loss of membrane phospholipid asymmetry, resulting in the exposure of phosphatidylserine at the surface of the cell. Expression of phosphatidylserine at the cell surface plays an important role in the recognition and removal of apoptotic cells by macrophages. Here we describe a new method for the detection of apoptotic cells by flow cytometry, using the binding of fluorescein isothiocyanate-labeled annexin V to phosphatidylserine. When Burkitt lymphoma cell lines and freshly isolated germinal center B cells are cultured under apoptosis inducing conditions, all cells showing chromatin condensation strongly stain with annexin V, whereas normal cells are annexin V negative. Moreover, DNA fragmentation is only found in the annexin V-positive cells. The nonvital dye ethidium bromide was found to stain a subpopulation of the annexin V-positive apoptotic cells, increasing with time. Our results indicate that the phase in apoptosis that is characterized by chromatin condensation coincides with phosphatidylserine exposure. Importantly, it precedes membrane damage that might lead to release from the cells of enzymes that are harmful to the surrounding tissues. Annexin V may prove important in further unravelling the regulation of apoptosis.     

骨髓干细胞移植对心肌梗死大鼠血流动力学指标和心脏功能的影响

目的:心肌梗死所致的细胞缺失和瘢痕形成是心力衰竭乃至死亡的病理基础,目前药物治疗、介入治疗和外科手术均不能替代坏死心肌和彻底改善心脏功能。观察骨髓干细胞移植对心肌梗死大鼠血流动力学指标和心功能的影响。方法:实验于2005-03/2006-10在哈尔滨医科大学附属第一医院细胞移植中心完成。①实验动物:SD雄性大鼠60只作为细胞移植的受体,随机数字表法分成假手术组、心肌梗死组、细胞移植组,20只/组。另取SD雄性幼鼠10只作为骨髓干细胞的供体。实验过程中对动物的处置符合动物伦理学标准。②实验方法:取幼鼠股骨骨髓,Percoll分离后收取细胞层,加入含体积分数为0.1的胎牛血清、100IU/mL青霉素、100g/mL链霉素的DMEM营养液,差速贴壁法分离骨髓干细胞,达80%～90%融合时采用胰酶 乙二胺四乙酸消化传代。向含有第3代骨髓干细胞的培养液中加入5-氮杂胞嘧啶核苷进行诱导,3周后行BrdU标记,离心后配制成1×1012L-1的细胞悬液用于移植。心肌梗死组、细胞移植组大鼠建立心肌梗死模型,假手术组未结扎冠状动脉。细胞移植组吸取0.2mL骨髓干细胞悬液注射到瘢痕组织中,心肌梗死组注入等量干细胞培养液基质,假手术组不予任何移植处理。③实验评估:术后4周,利用导管和心动超声技术检测各组大鼠左室舒张末期内压、左室收缩末期内压、左室压力最大变化值、左室压力最小变化值、等容时间常数和心率。结果:术后4周,与假手术组比较,心肌梗死组左室收缩末期内压、左室压力最大变化值、左室压力最小变化值均明显降低(P<0.01),左室舒张末期内压、等容时间常数均明显增高(P<0.01);与心肌梗死组比较,细胞移植组以上各项指标均明显好转(P<0.01)。结论:骨髓干细胞移植到瘢痕心肌组织中,能改善心肌梗死后大鼠的血流动力学参数和心脏功能。     

Biosynthesis and expression of VE-cadherin is regulated by the PI3K/mTOR signaling pathway

Vascular endothelial (VE)-cadherin is an essential protein of adherens junctions of endothelial cells and plays a pivotal role in vascular homeostasis. Mammalian target of rapamycin complex 2 (mTORC2) deficient mice display defects in fetal vascular development. Blocking mTOR or the upstream kinase phosphoinositide 3-kinase (PI3K) led to a dose-dependently decrease of the VE-cadherin mRNA and protein expression. Immunofluorescent staining showed a strongly decreased expression of VE-cadherin at the interface of human umbilical endothelial cells (HUVECs) followed by intercellular gap formation. Herewith, we demonstrated that the expression of VE-cadherin is dependent on mTOR and PI3K signaling.     

Clinical features of chromosome 22q11.2 microdeletion syndrome in 208 Chilean patients

Patients with chromosome 22q11 deletion syndrome exhibit significant phenotypic variability. Epidemiologic data suggest a higher incidence in Hispanics, but limited clinical information is available from Latin-American patients. We describe the clinical features of Chilean patients with 22q11 deletion syndrome and compare their findings with those reported in large European, Japanese and US series. Data were obtained from 208 patients from five medical centers. Mean age at diagnosis was 5.2 years, with a median of 2.3 years. Congenital heart defects were present in 59.6%, lower than other large series that averaged 75.8%. Palate abnormalities were present in 79%, higher than previous reports averaging 56%. Patients with congenital heart disease were diagnosed earlier (median 0.3 years of age) than those without heart defects (median 5.6 years) and had greater mortality attributable to the syndrome (9.8% vs 2.4%, respectively). The differences in frequencies of major anomalies may be due to growing awareness of more subtle manifestations of the syndrome, differences in clinical ascertainment or the presence of modifier factors. These observations provide additional data useful for patient counseling and for the proposal of health care guidelines.     

Therapeutic action and underlying mechanisms of a combination of two pentacyclic triterpenes, α- and β-amyrin,in a mouse model of colitis

Background and purpose:

α- and β-amyrin are pentacyclic triterpenes found in plants and are known to exhibit pronounced anti-inflammatory effects. Here, we evaluated the effects of a 1:1 mixture of α- and β-amyrin (α,β-amyrin) on an experimental model of colitis in mice.

Experimental approach:

Colitis was induced in Swiss male mice by trinitrobenzene sulphonic acid (TNBS) and followed up to 72 h; animals were treated systemically with α,β-amyrin, dexamethasone or vehicle. Macro- and microscopic damage, myeloperoxidase activity and cytokine levels were assessed in colons. Histological sections were immunostained for cyclooxygenase-2 (COX-2), vascular endothelial growth factor, phospho-p65 nuclear factor-κB (NF-κB) and phospho-cyclic AMP response element-binding protein (CREB)

Key results:

TNBS-induced colitis was associated with tissue damage, neutrophil infiltration and time-dependent increase of inflammatory mediators. Treatment with α,β-amyrin (3 mg·kg⁻¹, i.p.) or dexamethasone (1 mg·kg⁻¹, s.c.) consistently improved tissue damage scores and abolished polymorphonuclear cell infiltration. α,β-Amyrin, like dexamethasone, significantly diminished interleukin (IL)-1β levels and partially restored IL-10 levels in colon tissues 72 h after colitis induction, but only α,β-amyrin reduced vascular endothelial growth factor expression by immunohistochemistry. The colonic expression of COX-2 at 24 h and that of phospho-NF-κB and phospho-CREB (peaking at 6 h) after colitis induction were consistently inhibited by both α,β-amyrin and dexamethasone.

Conclusions and implications:

Systemic administration of α,β-amyrin exerted a marked and rapid inhibition of TNBS-induced colitis, related to the local suppression of inflammatory cytokines and COX-2 levels, possibly via inhibition of NF-κB and CREB-signalling pathways. Taken together, our data suggest a potential use of α,β-amyrin to control inflammatory responses in bowel disease.