Lysosomal abnormalities in degenerating neurons link neuronal compromise to senile plaque development in Alzheimer disease

Antibodies to the lysosomal hydrolases, cathepsins B and D and β-hexosaminidase A, revealed alterations of the endosomal-lysosomal system in neurons of the Alzheimer disease brain, which preceded evident degenerative changes and became marked as atrophy, neurofibrillary pathology, or chromatolysis developed. At the earliest stages of cell atrophy, hydrolase-positive lysosomas accumulated at the basal pole and then massively throughout the perikarya and proximal dendrites of affected pyramidal neurons in Alzheimer prefrontal cortex and hippocampus, far exceeding the changes of normal aging. Secondary lysosomes as well as tertiary residual bodies (lysosomes/lipofuscin) increased implying stimulated, autophagocytosis and lysosomal system activation. Less affected brain regions, such as the thalamus, displayed similar though less extensive alterations. Certain thalamic neurons exhibited a distinctive lysosome-related abnormality characterized by the presence of cell surface blebs of varying size and number filled with intense hydrolase immunoreactivity. At more advanced stages of degeneration in still intact neurons, hydrolase-positive lipofuscin, particularly in the form of abnormal large aggregates, nearly filled the cytoplasm. Similar lipofuscin aggregates were oberved in abundance in the extracellular space following cell lysis and were usually associated with deposits of the β-amyloid protein. Degenerating neurons and their processes were the major source of these aggregates within senile plaques which contained high concentrations of acid hydrolases. We have shown in previous studies that these lysosomal hydrolases in plaques are enzymatically-active. The persistence of lysosomal structures in the brain parenchyma after neurons hyve degenerated is a striking and potentially diagnostic feature of Alzheimer disease which has not been observed, to our knowledge, in other degenerative diseases. The lysosomal response in degerating Alzheimer neurons represents a probable link between an early activation of the lysosomal system in at-risk, normal-appearing neurons and the end-stage contribution of lysosomes to senile plaque formation of emphasizes a slowly progressive disturbance of the lysosomal system throughout the development of Alzheimer disease.     

卒中高危人群糖化血红蛋白与颈动脉粥样硬化斑块的关系研究

目的 分析卒中高危人群糖化血红蛋白与颈动脉粥样硬化斑块的关系。
方法 2018年5-6月由孝感市中心医院按整群随机抽样方法，随机抽取孝感市城乡各1个社区居民
进行筛查，通过问卷调查、体格检查、实验室检查、颈部血管超声检查筛选卒中高危人群纳入研究。
根据颈动脉超声检测结果将卒中高危人群分为非斑块组和斑块组（颈动脉）。分别采用单因素和多
因素Logistic回归，分析糖化血红蛋白与颈动脉斑块的关系，并根据年龄（60岁）、BM（I 24 kg/m2）、是
否有高血压对研究人群进行分层分析，研究不同特征的卒中高危人群中糖化血红蛋白与颈动脉斑块
的关系。
结果 最终纳入卒中高危人群629例，男性338例（53.74%），平均54.85±8.97岁，糖化血红蛋白平
均浓度为4.70%±1.02%。其中斑块组患者215例（34.18%），非斑块组患者414例（65.82%）。与非斑
块组患者相比，斑块组患者男性、卒中、TIA、高血压、超重患者比例更高，年龄更大，BMI、血压、空
腹血糖、糖化血红蛋白、TC水平更高（均P＜0.01）。校正其他危险因素后，糖化血红蛋白是颈动脉
粥样硬化斑块发生的独立影响因素（每升高1%，OR 1.16，95%CI 1.01～1.31，P =0.018）。分层分析显
示，年龄≥60岁（OR 1.48，95%CI 1.09～2.01，P =0.016）、BMI≥24 kg/m2（OR 1.97，95%CI 1.07～3.64，
P =0.030）、高血压人群（OR 1.31，95%CI 1.06～1.62，P =0.013）中糖化血红蛋白均是颈动脉斑块发生
的独立危险因素。
结论 卒中高危人群糖化血红蛋白与颈动脉斑块的发生密切相关，特别是在年龄≥6 0岁、
BMI≥24 kg/m2和高血压人群中。     

对急性冠状动脉综合征的新认识和治疗对策

近几年来，由于基础实验研究的迅速发展，对急性冠状动脉综合征(ACS)的认识和治疗取得了重大进展。作者就ACS分子生物学和细胞学基础、不稳定斑块的治疗对策、ACS的危险分层及治疗方法作一综述。     

Ultrasound for the assessment of the embolic risk of carotid plaques

In a prospective study we compared duplex-ultrasound characteristics of symptomatic internal carotid artery (ICA) stenoses with cranial computerized tomographic (CCT) findings in 82 patients suffering from completed or transient middle cerebral artery symptoms. The aim was to assess the pathogenic role of ICA plaque morphology and the potential embolic risk of ICA plaques. The degree of carotid stenosis was estimated by spectral analysis of the pulsed Doppler signal. The CCT findings were classified as being either normal, lacunar lesions, hemodynamically induced low-perfusion infarctions, or territorial embolic infarctions. According to their ultrasonic features we characterized the ICA plaque surface as smooth or irregular and their structure as homogeneous or heterogeneous. Plaques with an irregular surface and heterogeneous echogenicity dominated significantly in CCT-territorial infarctions (p < 0.01), whereas hemodynamically induced low-perfusion infarctions showed no relationship with any plaque characteristic. High degree ICA stenoses (> 50>%) dominated in both territorial infarctions and low-perfusion infarctions, as compared to ipsilateral normal CCT or lacunes (p < 0.05). Normal CCT and lacunar infarctions were associated with homogeneous and smooth plaques (both p < 0.05). We conclude that > 50% ICA stenoses can cause both hemodynamically induced low-perfusion infarctions as well as thromboembolic territorial infarctions, whereas ulcerated and heterogeneous plaques constitute a high risk factor for arterio-arterial embolic stroke. Furthermore, carotid ultrasound may help to estimate the clinical significance of carotid lesions.     

龈下优势菌在冠、桥修复材料表面定植量的测定

为考察冠、桥修复材料对微生物定植的影响。探讨微观评价冠、桥修复材料的标准，本研究选用SDA-Ⅱ型中熔合金、烤瓷熔附金属材料=湿热固化冠用塑料、plat铸造陶瓷4种材料和血链球菌、粘性放线菌、具核梭杆菌、黄褐二氧化碳噬纤维菌4种龈下优势菌，通过3，7，14d连续厌氧培养，测定试件PBS洗涤液中微生物OD值，考察定植在材料表面的微生物量，本研究表明，不同细菌对不同材料定植量不同，与材料表面的结构、成分、抗腐蚀性以及抗溶解性有关。     

A clinical comparison of 2 electric toothbrush designs

Abstract A single blind 30 day study compared the reduction of plaque and gingivitis for the Hapika® Powerbrush to the Interplak® ultra 10 tuft. A longitudinal parallel group design was utilized and screening evaluation was performed to determine patient eligibility prior to study enrollment. 66 subjects were entered into the study and assigned to 1 of 2 groups, each using one of the toothbrushes. At baseline, subjects received an oral soft tissue exam, a dental hard tissue exam, and were scored by the Lobene modification of the Löe and Silness gingival index (GI). Plaque was then disclosed and scored both pre and post brushing using the modified Turesky plaque/debris examination and an interproximal bleeding examination was performed post-brushing. On days 15 and 30, after an oral soft tissue and GI examination, plaque was graded by the Modified Turesky plaque/debris exam. Subjects then brushed and were graded by the Modified Turesky plaque/debris examination and an interproximal bleeding index examination. The results showed that both brushes provided a similar change in clinical indices. All produced a statistically significant reduction from baseline to day 30 for the gingival index (26.5-29.1%), the bleeding index (13.8-24.1%), and the plaque index (16.9-19.4%), A comparison of pre and post brushing scores for the plaque index at 30 showed that both brushes reduced plaque similarly with a statistically significant reduction (P<0.05) from their pre-brushing plaque index scores at all time periods.     

Immunohistochemical localization of tissue factor pathway inhibitor-1 (TFPI-1), a Kunitz proteinase inhibitor, in Alzheimer''s disease

Senile plaques in Alzheimer's disease (AD) are composed principally of Aβ, a 4 kDa fragment of the amyloid precursor protein (APP). Longer forms of APP which contain a Kunitz proteinase inhibitor (KPI) domain are elevated in aged and in AD brains. Tissue factor pathway inhibitor-1 (TFPI) contains three tandem KPI domains and has been well characterized for its role as a natural anticoagulant in the extrinsic coagulation pathway. Functionally, the first two KPI domains of TFPI bind and inhibit the activity of factor Xa and VIIa respectively. In addition, TFPI and APP-KPI share a common clearance mechanism through the low density lipoprotein receptor-related protein (LRP). As part of an ongoing study of the role of KPI-containing proteins in AD, the current study examines TFPI localization in the brain. We report here that TFPI is immunohistochemically localized to microglia in both AD and non-AD individuals and is localized to some senile plaques in AD. Western blot analyses indicate that the amount of TFPI is elevated in frontal cortex samples from AD brains. We propose that TFPI may play a cell specific role in proteinase regulation in the brain.     

Comparison of silver stainings and immunohistology for the detection of neurofibrillary tangles and extracellular cerebral amyloid in paraffin sections

Summary The sensitivities of six silver-staining methods and immunohistology for beta and tau protein were compared for their ability to demonstrate neurofibrillary tangles (NFT) and senile plaques (SP) in paraffin sections. Serial sections of the hippocampal area of 35 brains showing these neuropathological findings were cut and stained by the methods of Cross, Campbell, Bielschowsky, Gallyas, Yamaguchi, our variant (method of Reusche) and immunohistology. In the detection of NFT, the techniques of Gallyas, Bielschowsky, our method and tau protein immunostaining were the most sensitive methods. The procedure of Campbell and again our method were proven to be superior to the other stainings in demonstrating SP as well as diffuse and subpial amyloid. Moreover, our method reliably stained vascular and perivascular amyloid which can be identified in brains with congophilic angiopathy. Due to a lack of control in certain steps of the procedures most of the silver-staining methods are complicated and to not present reliable results. Our variant is easy to perform and, thus, may be used as a sensitive, simple and reliable alternative for the impregnation of the main lesions (NFT and SP) occurring in senile dementia of Alzheimer type and brains with normal aging for screening, retrospective and quantitative studies and for routine purposes.Parts of this paper were presented at the IV. European Meeting of Neuropathology, Berlin Germany, 1992     

Transmission electron microscopy of early microbial colonization of human enamel and root surfaces in vivo

Abstract – This study describes the early microbial colomization of teeth by the use of light-and transmission electron microscopy. Six dental students carried a total of 60 test pieces of unerupted enamel and root surface in intraoral acrylic appliances for 4, 8, 12, 24 and 48 h, during which periods oral hygiene was abandoned. Pronounced variations were recorded in structure and thickness of the pellicle across the individual surfaces of both dental tissues. Bacterial single-cell colonization increased the electron density of the adjoining pellicle. Micro-colonies of bacteria were observed in relation to enamel surface irregularities such as perikymata, while the distribution on root surfaces appeared incidental. Root surfaces were generally colonized by thicker deposits than homologous enamel surfaces although the structural composition of the microbiota was similar. Gram-positive bacteria with thick cell walls appeared in coccoid or rod-shaped configurations depending on the age of the bacterial deposit. These bacteria were further characterized by selective invasion between collagen fibers. After 48 h the complexity of the microbiota was increased by the establishment of new bacterial species in the superficial layer. It is concluded that the pattern and composition of the early microbiota on teeth is more complex and variable than hitherto assumed.     

"Reverse" DMA hybridization method for the rapid identification of subgingival microorganisms

A "reverse" hybridization method is described, in which whole chromosomal DNA was extracted from 10-20 colonies of "unknown" strains in pure culture and labelled with digoxigenin by a random primer technique. DNA probes were prepared from a total of 23 strains and hybridized with targets containing 100 ng purified, denatured DNA from 38 reference strains fixed to nitrocellulose. 21/23 digoxigenin-labelled DNA probes successfully detected all members of the homologous species present on filters. Probes to Fusobacterium nucleatum strains 364 and MG detected 3/4 and 1/4 members of this species, respectively; 13/23 probes were 100% specific, but cross reactions between 10 probes and DNA targets from closely related, heterologous species occurred in 15/834 possible instances. False-positive reactions that occurred between closely related species were, however, easily distinguished and did not prevent the accurate identification of probe strains. Digoxigenin-labelled probes were capable of detecting 100 pg of homologous DNA. The reverse hybridization procedure allows identification or grouping of a large number of isolates within 3 days and provides a more economical means of characterizing subgingival isolates than predominant cultivable techniques and conventional phenotypic testing. This method could be adapted for the direct identification of microorganisms in subgingival plaque samples.