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At least 487 records · Page 27Linked to original sources
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↗
PubMed2000

A metal-chelating microscopy tip as a new toolbox for single-molecule experiments by atomic force microscopy.

In recent years, the atomic force microscope (AFM) has contributed much to our understanding of the molecular forces involved in various high-affinity receptor-ligand systems. However, a universal anchor system for such measurements is still required. This would open up new possibilities for the study of biological recognition processes and for the establishment of high-throughput screening applications. One such candidate is the N-nitrilo-triacetic acid (NTA)/His-tag system, which is widely used in molecular biology to isolate and purify histidine-tagged fusion proteins. Here the histidine tag acts as a high-affinity recognition site for the NTA chelator. Accordingly, we have investigated the possibility of using this approach in single-molecule force measurements. Using a histidine-peptide as a model system, we have determined the binding force for various metal ions. At a loading rate of 0.5 microm/s, the determined forces varied from 22 +/- 4 to 58 +/- 5 pN. Most importantly, no interaction was detected for Ca(2+) and Mg(2+) up to concentrations of 10 mM. Furthermore, EDTA and a metal ion reloading step demonstrated the reversibility of the approach. Here the molecular interactions were turned off (EDTA) and on (metal reloading) in a switch-like fashion. Our results show that the NTA/His-tag system will expand the "molecular toolboxes" with which receptor-ligand systems can be investigated at the single-molecule level.

Chelating Agents↗
PubMed2006

[Confocal microscopy in corneal dystrophies: a comparison between confocal slit scanning (ConfoScan P2) and laser scanning microscopy (Rostock Cornea Modul-HRT II)].

BACKGROUND: The object of this work was a comparison of confocal images of corneal dystrophies made by a slit scanning microscope versus a laser scanning microscope. MATERIAL AND METHODS: Using the Rostock Cornea Modul-HRT II as a confocal laser scanning microscope the images of five patients with some epithelial, stromal and endothelial corneal dystrophies were acquired. The pictures were compared qualitatively with those taken by the slit scanning microscope "ConfoScan P2" from corresponding pathologies. Also, the images of normal corneas of ten healthy persons were acquired for a qualitative comparison. RESULTS: Confocal images from both devices were able to provide significant helpful diagnostic findings about the corneal microstructure. Essential qualitative differences between the images of both devices used were not observed. Due to the additional hardware components and the software module for image acquisition, analysis and archiving, the RCM-HRT II is favoured over the "ConfoScan P2". Nevertheless, the evaluation in favour of the RCM-HRT II has to be confined because an optimised, user-friendly enhancement, the "ConfoScan 4" is currently available. CONCLUSION: Evaluating corneal dystrophies in vivo, an equivalent utility of both technical approaches has been observed.

Adult↗
PubMed1960

A correlative study by electron and light microscopy of the development of type 5 adenovirus. II. Light microscopy.

The evolution of the intranuclear lesion produced by type 5 adenovirus in HEp-2 and HeLa cells is described as seen in the light microscope and the bodies formed in the course of the infection characterized histochemically. Some 12 hours after infection acidophilic protein bodies, without appreciable nucleic acid, first appear in the nucleus and coalesce into a network. Within or in association with this material, DNA-containing masses (viral aggregates) are formed which rapidly increase in amount and then coalesce. At the same time, a protein is produced, histochemically different from that of the acidophilic or basophilic structures mentioned, within the infected nucleus, which constitutes a matrix within which regular cytstals of a protein, (presumably non-viral) materialize. These structural and histochemical features are correlated with details which have been observed in parallel studies with the electron microscope.

Adenoviridae↗
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↗
PubMed2006

DNA fragmentation assessment by flow cytometry and Sperm-Bos-Halomax (bright-field microscopy and fluorescence microscopy) in bull sperm.

The aim of this study was to find the relationship between fertility (as 90-day non-return rates) and DNA fragmentation assessed by two techniques [sperm chromatin structure assay (SCSA) and Sperm-Bos-Halomax (SBH)]. Furthermore, other quality parameters were achieved (motility, morphological abnormalities, cytoplasmic droplets, viability, capacitation and acrosomal and mitochondrial status) and their correlations with fertility were analysed. Bulls were divided into three fertility groups: high [non-return rate (NRR) >or= 80], medium (80 < NRR >or= 70) and low (70 < NRR > 40). The results of this study indicate that there is a good correlation between fertility and different parameters of sperm quality (SBH and SCSA parameters, % of spermatozoa with head, neck and total abnormalities, and % of spermatozoa with proximal cytoplasmic droplets) and differences between fertility groups were observed in some of them (SBH and SCSA parameters and % of spermatozoa with head, neck and total abnormalities). In this sense, SBH parameters rendered good correlations with fertility (r = -0.42 using bright light microscope and r = -0.47 with fluorescence). Also, standard deviation of DNA fragmentation index (SD-DFI) and DFIh (cells with High DNA fragmentation index) showed good correlations with fertility (r = -0.41 and r = -0.29). No correlations were observed between SCSA and SBH parameters. A multiple regression shows that four parameters (% of proximal cytoplasmic droplets, % of intact acrosomes in total population, SD-DFI and percentage of fragmented DNA detected by bright light microscope) present a good predictive value of the fertility of sperm samples (r(2) = 0.34, p < 0.001).

Acrosome↗
PubMedDate not supplied

Choroidal vasculature changes in spontaneously hypertensive rats - transmission electron microscopy and scanning electron microscopy with casts.

PURPOSE: The purpose of the present study was to elucidate the specific morphological changes of the choroidal vasculature in long-term hypertension. METHODS: The choroidal vessels of spontaneously hypertensive (SHR) rats were examined with corrosion casts/scanning electron microscope (SEM) and the transmission electron microscope (TEM). RESULTS: In 18-month-old SHRs, corrosion casts and SEM showed tortuosity, caliber irregularity and generalized narrowing of the choroidal arteries. The draining venules were prominently decreased in number. The ampullae of the vortex veins were narrow, but arteriovenous anastomoses, crossing defects and obstruction were not seen. The choriocapillaris was elongated and engorged. TEM of the choroidal vessels showed hypertrophy of smooth muscle cells and irregular thickening of the basement membrane and narrow lumen of the choriocapillaris. The RPE and Bruch's membrane were intact. CONCLUSION: The choroidal vascular bed showed extensive morphological changes. This study revealed that hypertensive choroidopathy has specific features such as tortuosity, caliber irregularity, generalized narrowing of arteries, decreased number of draining venules and elongated and engorged choriocapillaris. These findings indicate that hypertensive choroidopathy is as important as retinopathy.

Animals↗