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At least 451 records · Page 25Linked to original sources
PubMed1983

Co-ordinated electron microscopy and X-ray studies of glycerinated insect flight muscle. I. X-ray diffraction monitoring during preparation for electron microscopy of muscle fibres fixed in rigor, in ATP and in AMPPNP.

Synchrotron radiation was used for low-angle X-ray diffraction to monitor structural changes produced in insect flight muscle during fixation, dehydration and embedding for electron microscopy of thin sections. Fibre bundles were fixed by cold glutaraldehyde in one of three states, namely rigor, ATP or AMPPNP, followed by additional cross-linking treatment. No heavy metals were used before embedding. During fixation-embedding, all specimens lost the continuous actin layer lines of spacing 11-5 nm, shrank 18-21% in lattice spacing, shrank 0.5-2.5% in axial spacings and showed equatorial intensity changes which were similar for all three states, while the well-sampled inner layer lines (39-13 nm) were preserved with different fidelity in each state, highest for rigor and lowest for ATP. In different AMPPNP bundles, these layer lines indicated different degrees of unexplained shift (from slight to total) towards the structure of muscle fixed in ATP. Fixation in ATP caused obvious gain of intensity on 39, 19 and 13 nm layer lines, which can be interpreted as trapping of myosin crossbridge attachments to actin; this artifact was unchanged by seven variations in fixation conditions. Fixation in rigor gave no indication of crossbridge detachment nor of the presence or alteration of any significant population of non-bridging myosin heads. X-ray monitoring allowed selection of best-preserved samples for subsequent electron microscopy. The rapid pattern-recording possible with synchrotron X-ray intensity allowed us to complete and compare experiments with many fibre bundles from a single glycerinated Lethocerus muscle.

Adenosine Triphosphate↗
PubMedDate not supplied

Monte Carlo analysis of the detection of clay occlusion of respirable quartz particles using multiple voltage scanning electron microscopy.

The electron incident-energy dependence of the relative intensities of Al and Si x-rays produced in a respirable-sized quartz particle by scanning electron microscopy is sensitive to the inhomogeneity of the distribution of Al and Si in the particle. Realistic Monte Carlo calculations of this energy dependence validate the proposal to use this effect for the detection of particles in which an aluminosilicate coating occludes the surface of a silica core.

Journal Article↗
PubMed1999

[The standardized techniques for preparing samples used in pathologic diagnostic transmission electron microscopy].

Transmission electron microscopy (TEM) has been used widespreadly in the field of diagnostic pathology. Based on the practical domestic condition and aimed at fully satisfying the needs of the pathologic diagnostic TEM, a set of standardized techniques were established for preparing different kinds of samples. The techniques included the preparation and storage of fixatives and embedding media, the requirement of sampling, the 5 h and 24 h embedding procedures for fresh specimens, the embedding procedure for suspension specimens and specimens collected from fine needle aspiration biopsy, as well as the procedures for preparing samples taken from paraffin embedded blocks or paraffin sections. In practical use, we found that the advantage of these techniques was that the ultrastructures of the tissues and cells were well preserved and they perfectly met the needs for diagnosis of tumors, kidney diseases, et al. The main points of the standardized techniques have been discussed in detail in this paper.

Breast Neoplasms↗
PubMed1991

[Effect of promoting biliation mixture on E. coli lipopolysaccharide under electron microscopy].

With electron microscopy this article observed the effect of promoting biliation mixture (PBM) and polymyxin B on E. coli lipopolysaccharide (LPS). The result showed that PBM could breakdown the typical structure of E. coli LPS with only short sections or partially disaggregate it. The morphology changes were similar to the effect of polymyxin B. It would appear that the loss of endotoxicity caused by PBM may be due to the loss of structural integrity of the E. coli LPS. The result may also give some evidence for the clinical effects of PBM theoretically.

Cholagogues and Choleretics↗
PubMed1987

Fixation of neural tissue for electron microscopy with an electronically controlled perfusion pump.

Many attempts to improve the perfusion of mammalian tissues aim at changes of the osmotic pressure. We describe a method for fixation of nervous tissues controlling both the hydrostatic pressure and the flow rate of a perfusion solution. The constancy of these parameters is guaranteed by an electronically controlled perfusion pump. Thus, a more uniform and complete preservation can be achieved. Further advantages of this method include provision for a rapid succession of rinsing and fixation solution and a continuous control of the hydrostatic pressure during perfusion.

Animals↗
PubMed1981

Scanning electron microscopy of cyclophosphamide-induced hyperplasia of the rat urinary bladder.

Urinary bladder damage caused by cyclophosphamide in male F344 rats was studied by light microscopy, scanning electron microscopy, and autoradiography. Cyclophosphamide was injected intraperitoneally at doses of 50, 75, 100, 150, and 200 mg. per kg. of body weight, and rats were killed at several intervals following treatment. Extensive necrosis of the bladder was followed by regenerative hyperplasia of the epithelium. A dose response was evident in the number and size of lesions induced and the time of regeneration and repair. Scanning electron microscopy disclosed pleomorphic microvilli on the luminal surface of cells during the early phases of hyperplasia. The greatest number of cells with pleomorphic microvilli occurred 2, 5 and 7 to 8 days following injection of 75, 100, and 200 mg. per kg. of cyclophosphamide, respectively. The hyperplastic lesions also had cells with short, uniform microvilli and ropy or leafy microridges on their surfaces. Autoradiographs of the urinary bladders showed marked labeling of epithelial cells in the early phase of hyperplasia. Of the few rats surviving beyond 1 year after a single injection, none had bladder lesions at any of the dose levels. The changes in the epithelium observed by scanning electron microscopy following cyclophosphamide injection were compared to those observed during bladder carcinogenesis.

Animals↗
PubMed1984

Pseudoreplica electron microscopy for the detection of rotavirus: comparison with high-speed centrifugation electron microscopy and ELISA.

Three-hundred and sixty-three stool specimens from patients with diarrhoea were examined for rotaviruses to compare the sensitivity of the pseudoreplica technique (PSD-EM) to that of high-speed centrifugation EM (HSC-EM) in relation to a commercially available (Rotazyme, Abbott) enzyme-linked immunosorbent assay (ELISA). In ELISA-positive cases, both methods were of equal sensitivity. However, in borderline (+/-) and ELISA-negative specimens, PSD-EM detected 31 of 48 (64.6%) and 18 of 229 (8%) positive specimens respectively, compared to only 22 of 48 (45.8%) and one of 229 (0.4%) positives detected by HSC-EM. PSD-EM detected a significantly higher number of positives compared to HSC-EM (p less than 0.05). In view of its simplicity, sensitivity and the fact that a relatively large number of specimens could be processed compared to HSC-EM, we consider that PSD-EM is a much better procedure for routine screening and diagnosis of viral gastroenteritis than HSC-EM.

Centrifugation↗
PubMed1993

Intestinal lesions in experimental phocine distemper: light microscopy, immunohistochemistry and electron microscopy.

The involvement of the intestinal mucosa and of the gut-associated lymphoid tissue in phocine distemper was studied in six severely diseased harbour seals 11 to 16 days after experimental infection. Five seals exhibited a mild or moderate enteritis in the small or large intestine. In all the seals, a moderate to severe depletion of submucosal lymphoid follicles was found. Likewise, antigen of phocine distemper virus (PDV) was demonstrated immunohistochemically in the intestinal wall of all the seals. Most antigen was found in the submucosal lymphoid follicles, followed by the crypt epithelium and follicle-associated epithelium (FAE). Ultrastructurally, intracytoplasmic tubular structures were detected in the FAE and interpreted as morbilliviral nucleocapsids. The results indicate a direct cytopathogenic effect of PDV on intestinal lymphoid and epithelial cells and suggest an important role of the intestinal tract in phocine distemper and, by analogy, in other morbillivirus infections as a regular site of virus replication, virus shedding and immunosuppression.

Animals↗
PubMed1990

Acne keloidalis. Transverse microscopy, immunohistochemistry, and electron microscopy.

The earliest stages of acne keloidalis are not well characterized. In the present study, transverse sections of the early lesions revealed follicular units in several stages of inflammation. These follicles surrounded the central follicular units that gave rise to the clinically evident papule. Despite a spectrum of inflammatory changes, the most marked inflammation consistently occurred in the deep infundibular and isthmian levels of the hair follicles. Two follicles, presumably in the earliest stage, exhibited primarily an acute folliculitis and perifolliculitis, with destruction of the follicular wall and the release of hair. Central follicles showed predominantly acute neutrophilic or chronic lymphocytic inflammation at the upper isthmian levels and granulomatous inflammation at the deeper isthmian levels. Other follicles showed scar at the isthmian levels trapping hair fragments in the inferior portion of the follicle, with granulomatous inflammation and scarring. Sebaceous glands were absent in all stages of folliculitis in seven of eight follicular units.

Acne Keloid↗
PubMed1976

Light microscopy and scanning electron microscopy of Bathmostomum sangeri Cobbold, 1879, of elephants.

Bathmostomum sangeri is an intestinal parasite of the elephant. Males measured 12.15-14.25 mm in length; females measured 14.98-17.68 mm in length. Buccal capsule is well-developed and funnel-shaped. There is a raised and transverse fissure ridge around the oral margin. The internal wall of the buccal capsule is raised into a series of circular ridges or lamellae. Teeth or cutting plates could not be seen. Spicules are stout, wing-like structures. The telamon is pear-shaped, but a gibernaculum is not present. There are two pairs of papillae on the either side of the cloacal opening. The female tail is gradually tepering.

Ancylostomatoidea↗