Scanning microscopy. Supplement最新文献_第5页

Electron probe X-ray microanalysis of epithelial cells: aspects of cryofixation. 上皮细胞的电子探针x射线显微分析:冷冻固定的方面。

Scanning microscopy. Supplement Pub Date : 1994-01-01

K Zierold, H Hentschel, F Wehner, A Wessing

{"title":"Electron probe X-ray microanalysis of epithelial cells: aspects of cryofixation.","authors":"K Zierold, H Hentschel, F Wehner, A Wessing","doi":"","DOIUrl":"","url":null,"abstract":"Content and distribution of diffusible ions in epithelial cells were studied by scanning transmission electron microscopy and energy dispersive electron probe X-ray microanalysis of freeze-dried cryosections from trout kidney, rat liver and Malpighian tubules of Drosophila larvae. Cryofixation of small excised kidney and liver samples by rapid immersion into liquid propane resulted in intracellular K/Na-ratios < 1. In contrast, K/Na-ratios > 7 were obtained after in situ cryofixation by means of a cryopunching device which allows tissue pieces to be frozen during excision from the intact organ. Isolated hepatocytes cryofixed in a small droplet of culture medium had a K/Na-ratio of 3.7. After culturing the hepatocytes, the K/Na-ratio increased to 24. Effects of extracellular media of different composition on the intracellular element content were studied. Malpighian tubules of Drosophila larvae were cryofixed by rapid immersion into liquid propane, and the distribution of K across the cells forming the tubules from the basal to the apical cell membrane was measured. An increasing K gradient was found from the intermediate to the apical cytoplasm. The intracellular K distribution was dependent on ions and transport inhibitors present in the fluid surrounding the Malpighian tubules within the larvae. Content and distribution of ions in epithelial cells sensitively depend on the physiological state immediately before cryofixation. Thus, electron probe X-ray microanalysis of cells and cell functions requires careful selection and control of the cell system to be studied.","PeriodicalId":77379,"journal":{"name":"Scanning microscopy. Supplement","volume":"8 ","pages":"117-26; discussion 126-7"},"PeriodicalIF":0.0,"publicationDate":"1994-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18644783","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

The preparation of cultured cells for X-ray microanalysis. 用于x射线微量分析的培养细胞的制备。

Scanning microscopy. Supplement Pub Date : 1994-01-01

A Warley

引用次数: 0

Biological electron energy loss spectroscopy in the field-emission scanning transmission electron microscope. 场发射扫描透射电子显微镜中的生物电子能量损失谱。

Scanning microscopy. Supplement Pub Date : 1994-01-01

R D Leapman, S Q Sun, J A Hunt, S B Andrews

{"title":"Biological electron energy loss spectroscopy in the field-emission scanning transmission electron microscope.","authors":"R D Leapman, S Q Sun, J A Hunt, S B Andrews","doi":"","DOIUrl":"","url":null,"abstract":"The dedicated scanning transmission electron microscope (STEM) combined with parallel electron energy loss spectroscopy (EELS) provides a very sensitive means of detecting specific elements in small structures. EELS is more sensitive than optimized energy-dispersive X-ray spectroscopy by a factor of about three for calcium. Measurement of such low concentrations requires special processing methods such as difference-acquisition techniques and multiple least squares procedures for fitting reference spectra. By analyzing data recorded at each pixel in a spectrum-image it is possible to map quantitatively the elemental distributions in a specimen. It is possible to prepare cryosections that are sufficiently thin to avoid excessive plural inelastic scattering so analysis can be performed at 100 keV beam energy. Under optimal conditions, a resolution of 10 nm and detection limits of a few atoms are achievable for elements such as calcium, phosphorus and iron. In the field emission STEM certain types of chemical information can be extracted from biological specimens. Valence EELS has been exploited to measure water distributions in frozen hydrated cryosections.","PeriodicalId":77379,"journal":{"name":"Scanning microscopy. Supplement","volume":"8 ","pages":"245-58; discussion 258-9"},"PeriodicalIF":0.0,"publicationDate":"1994-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18643287","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

X-ray microanalysis of endocrine, exocrine and intestinal cells and organs in culture: technical and physiological aspects. 培养中内分泌、外分泌和肠细胞和器官的x射线显微分析:技术和生理方面。

Scanning microscopy. Supplement Pub Date : 1994-01-01

R Wróblewski, J Wroblewski

{"title":"X-ray microanalysis of endocrine, exocrine and intestinal cells and organs in culture: technical and physiological aspects.","authors":"R Wróblewski, J Wroblewski","doi":"","DOIUrl":"","url":null,"abstract":"In the present study methods for preparation of cultured cells and organ cultures for analytical electron microscopy are investigated. These methods allow qualitative and quantitative analysis of mobile ions in combination with biochemical or morphological studies. Cultured cells can be easily prepared for analytical microscopy and therefore use of in vitro systems for X-ray microanalysis has increased over the last few years. Two major, anhydrous preparation techniques, by which loss or redistribution of ions is minimized, were used: (1) Cells were cryosectioned and analysis carried out on freeze-dried sections obtained from frozen cell monolayers, pelleted cells or organ cultures. (2)Cells cultured on supports compatible with elemental analysis were frozen after removal of experimental media by rinsing, freeze-dried and analyzed. The first technique was applied to the studies of the elemental content of isolated Langerhans islets and thyroid follicles cultured in collagen gel. The second was used in studies of the ionic changes in enterocytes. Data obtained from organotypic cell cultures and cultures of single cells were compared with analytical data obtained from sections of corresponding tissues, where isolation, culturing and steps in processing such as removal of culture or experimental medium were omitted. It was shown that often culture systems fully acceptable to physiologists have an elemental composition different from that of tissue in situ and can not be regarded as fully normal tissue.","PeriodicalId":77379,"journal":{"name":"Scanning microscopy. Supplement","volume":"8 ","pages":"149-60; discussion 160-1"},"PeriodicalIF":0.0,"publicationDate":"1994-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18642700","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Ion microscopy in biology. 生物学中的离子显微镜。

Scanning microscopy. Supplement Pub Date : 1994-01-01

G H Morrison, I Gay, S Chandra

{"title":"Ion microscopy in biology.","authors":"G H Morrison, I Gay, S Chandra","doi":"","DOIUrl":"","url":null,"abstract":"Ion microscopy, a mass spectrometry based isotopic imaging technique, is uniquely suited for ion transport related problems in biological systems. Due to its high sensitivity, it can image the transport and distribution of both major and minor elements (isotopes) at subcellular resolutions. The images of major elements such as K, Na, CI, etc., can be viewed directly and recorded in real-time from the microchannel plate-fluorescent screen detector of the instrument. The low concentration physiologically important elements, such as Ca, need about one minute of integration for good quality imaging. The isotopic imaging capability of ion microscopy provides a unique approach for the use of stable isotopes as tracers. In this way, one can image both the endogenous and the transported isotopes independently. Strict cryogenic sample preparations are essential for ion transport studies. Correlative imaging of the same cell with laser scanning confocal microscopy and ion microscopy can positively identify smaller cytoplasmic compartments such as the Golgi apparatus in calcium images. We have identified the Golgi apparatus as a calcium storing organelle. Another unique application of ion microscopy is the imaging of boron from boronated drugs used in Boron Neutron Capture Therapy (BNCT) of cancer. Ion microscopy is capable of rapid screening of potential drugs for BNCT. This critical information is essential for the fundamental understanding of BNCT. Ion microscopy is now at the stage where it can provide previously unattainable answers to important biomedical questions.","PeriodicalId":77379,"journal":{"name":"Scanning microscopy. Supplement","volume":"8 ","pages":"359-70"},"PeriodicalIF":0.0,"publicationDate":"1994-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18643234","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A new versatile system for freeze-substitution, freeze-drying and low temperature embedding of biological specimens. 一种用于生物标本冷冻替代、冷冻干燥和低温包埋的新型多功能系统。

Scanning microscopy. Supplement Pub Date : 1994-01-01

H Sitte, L Edelmann, H Hässig, H Kleber, A Lang

{"title":"A new versatile system for freeze-substitution, freeze-drying and low temperature embedding of biological specimens.","authors":"H Sitte, L Edelmann, H Hässig, H Kleber, A Lang","doi":"","DOIUrl":"","url":null,"abstract":"A universal system for freeze-substitution (FS), freeze-drying (FD) and low temperature embedding (LTE) has been developed, suited to perform standardized procedures of cryoprocessing biological and medical specimens as well as systematic studies of dehydration and embedding at various low and high temperatures. In a 35 1 Dewar vessel with 110 mm neck diameter an aluminum tube is mounted to the bottom of the liquid nitrogen (LN2x) reservoir and extends to the lower part of the cylindrical neck. At its top an aluminum plate serves as a contact surface for either the FS chamber or the FD chamber. Fs and subsequent LTE are carried out in an environment of dry cold nitrogen gas provided by evaporating nitrogen from the dewar. Different capsules and moulds may be used for cryodehydration and LTE. FD of bulk specimens or cryosections takes place in an absolutely clean vacuum provided by a cryosorption pump integrated in the FD apparatus. Most of the H2O molecules from the frozen specimen are trapped by large cold surfaces inside the drying chamber. Due to the low LN2 consumption during FS or FD (3-4 1 LN2/day) both procedures may be carried out for 8-10 days without refilling the dewar. A few representative results show that well frozen biological material is stabilized by prolonged FS or FD at temperatures of about -80 degrees C without user of chemical fixatives like OsO4 in the substitution medium during FS or by OsO4 vapor fixation after FD.","PeriodicalId":77379,"journal":{"name":"Scanning microscopy. Supplement","volume":"8 ","pages":"47-64; discussion 64-6"},"PeriodicalIF":0.0,"publicationDate":"1994-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18643237","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Changes of ion and water content of mouse intestinal cells after pilocarpine and isoproterenol stimulation. 匹罗卡品和异丙肾上腺素刺激后小鼠肠细胞离子和水分含量的变化。

Scanning microscopy. Supplement Pub Date : 1994-01-01

T von Zglinicki, G M Roomans

{"title":"Changes of ion and water content of mouse intestinal cells after pilocarpine and isoproterenol stimulation.","authors":"T von Zglinicki, G M Roomans","doi":"","DOIUrl":"","url":null,"abstract":"Cytoplasmic monovalent ion and water contents in morphologically defined mice jejunal cells were measured by X-ray microanalysis in order to gain insight into the cell-type specificity of intestinal electrolyte transport mechanisms. Ion and water contents were measured independently. It was found that in some cases net fluxes of ions and water do not correspond to the assumption of constant osmotic activity of cytoplasmic Na and K ions. Stimulation of secretion with the cholinergic secretagogue pilocarpine resulted in efflux of Cl- from an influx of K+ into crypt enterocytes containing small secretion granula (crypt A cells). No significant changes in ion concentrations were found in crypt enterocytes without secretion granula (crypt B cells). Crypt A cells were more likely to be stimulated by pilocarpine than crypt B cells, and the basolateral K+ efflux pathway in crypt A cells appeared to be rate-limiting. In villus enterocytes, pilocarpine stimulated Cl- efflux. Isoproterenol caused marked changes in the cytoplasmic Cl content of all epithelial cells. These changes were reversed by inhibition of adenylate cyclase by alloxan, with the sole exception of Cl increase in villus absorptive cells. The results are consistent with an cAMP-mediated stimulated secretion in crypt epithelial cells and a predominantly cAMP-independent stimulation of absorption in villus cells. The results obtained suggest a transcellular route of Cl absorption in the mouse jejunum.","PeriodicalId":77379,"journal":{"name":"Scanning microscopy. Supplement","volume":"8 ","pages":"25-34; discussion 34-5"},"PeriodicalIF":0.0,"publicationDate":"1994-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18643288","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

New applications of the nuclear microprobe for biological samples. 核微探针在生物样品中的新应用。

Scanning microscopy. Supplement Pub Date : 1994-01-01

J Pallon, K Malmqvist

引用次数: 0

Electron microprobe analysis of electrolytes in whole cultured epithelial cells. 全培养上皮细胞电解质的电子探针分析。

Scanning microscopy. Supplement Pub Date : 1994-01-01

S Borgmann, M Granitzer, J Crabbé, F X Beck, W Nagel, A Dörge

{"title":"Electron microprobe analysis of electrolytes in whole cultured epithelial cells.","authors":"S Borgmann, M Granitzer, J Crabbé, F X Beck, W Nagel, A Dörge","doi":"","DOIUrl":"","url":null,"abstract":"Microprobe analysis was used to determine electrolyte contents in whole epithelial sheets of A6 cells and to investigate the most critical points of this method. Analysis of dextran standard sections of different thickness revealed that low accelerating voltages of about 10 kV are best suited for whole freeze-dried cells on thick supports, since 5 microM thick sections are not penetrated by 10 kV electrons. Washing of A6 cells for 10 sec with distilled water led to cell swelling of about 40%, but the molar concentration ratios and the concentrations per dry weight (dw) were not altered. Washing for 60 sec with distilled water caused a further increase in cell volume (120%) and loss of cellular K and Cl (90 mmol/kg dw). Washing with isotonic NH4- acetate led to a loss of cell Cl already after 10 sec. To characterize the Na transport compartment, A6 cells cultured on permeable supports were washed for 5 sec with distilled water, freeze-dried, and analyzed. Inhibition of transepithelial Na transport by ouabain increased Na/P from 0.15 +/- 0.07 to 0.75 +/- 0.03 and Cl/P from 0.21 +/- 0.001 to 0.38 +/- 0.003 while K/P decreased from 0.83 +/- 0.08 to 0.32 +/- 0.03. The changes in cell Na and K contents can be explained by K/Na exchange; the increase in Cl content indicates some cell swelling. Since the ouabain-induced changes could be prevented by apical amiloride, the apical membrane provides the most important pathway for Na entry in A6 cells.","PeriodicalId":77379,"journal":{"name":"Scanning microscopy. Supplement","volume":"8 ","pages":"139-47; discussion 148"},"PeriodicalIF":0.0,"publicationDate":"1994-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18642699","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Standards for X-ray microanalysis of calcified structures. 钙化结构的x射线显微分析标准。

Scanning microscopy. Supplement Pub Date : 1994-01-01

J A Lopez-Escamez, A Campos

{"title":"Standards for X-ray microanalysis of calcified structures.","authors":"J A Lopez-Escamez, A Campos","doi":"","DOIUrl":"","url":null,"abstract":"The ability of electron probe X-ray microanalysis (EPMA) to solve biological problems often depends on the use of a quantitative approach. EPMA allows the quantitative determination of chemical elements of biological materials by using reference standards which resemble the specimen in the mode of interaction with the electron beam. Although there is a large experience in the quantification of elements in biological thin specimens, experience with standards for X-ray microanalysis of bulk specimens is limited, especially for calcified structures where the density of the specimen is difficult to estimate. The quality of the results in EPMA depends on obtaining accurate calibration curves which allow the establishment of the relationship between the signal measured and the concentration of the element of interest. The different methods for specimen preparation and the thickness of the specimen will also determine the precise nature of the standardization technique to be adopted. The physics of the electron beam-specimen interactions impose limitations upon the accuracy of calibration, and the choice of an unstable standard can result in large errors in the quantification of elements. We have reviewed the different types of compounds that have been used as standards for biological EPMA of thin and bulk specimens and discuss their potential use for quantitative analysis of mineralized tissues, with special reference to otoconia, the calcified structures of the vestibular system.","PeriodicalId":77379,"journal":{"name":"Scanning microscopy. Supplement","volume":"8 ","pages":"171-85"},"PeriodicalIF":0.0,"publicationDate":"1994-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18642702","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0