Scanning electron microscopy of the floor of the fourth ventricle in rats subjected to graded impact injury to the sensorimotor cortex

1999 ◽  
Vol 90 (4) ◽  
pp. 734-742 ◽  
Author(s):  
Theodore G. Sarphie ◽  
Michael E. Carey ◽  
June F. Davidson ◽  
Joseph S. Soblosky
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Head Injury ◽  
Sensorimotor Cortex ◽  
Fourth Ventricle ◽  
Structural Integrity ◽  
Area Postrema ◽  
Content Type ◽  
Fine Print ◽  
Scanning Electron

Object. Respiratory dysfunction including apnea frequently follows head injury in humans. The purpose of this study was to identify any structural alterations in the region of brainstem respiratory nuclei that might account for immediate postinjury respiratory abnormalities in anesthetized experimental animals.Methods. Using scanning electron microscopy, the authors examined the floor of the fourth ventricle in injured rats after a piston strike to the sensorimotor cortex that depressed the dura 1, 2, or 4 mm. The rats were killed within minutes of injury. Cortical impact depths measuring either 1 or 2 mm (eight rats) produced no respiratory abnormalities, and the structural integrity of the ependymal lining of the ventricular floor in these animals was not compromised. Thirteen rats were subjected to impact to a 4-mm depth and 10 of these exhibited immediate temporary or permanent apnea. The medullae of nine of these rats were studied using scanning electron microscopy, and the fourth ventricular floors of all nine rats showed tears. Four rats that exhibited immediate, permanent apnea had tears in the caudal fourth ventricle floor near the obex, whereas five rats with no or only transient apnea had tears located more anteriorly, near the aqueduct or laterally. Changes in cerebrospinal fluid flow or pressure dynamics may have caused these tears. Light microscopy, focused near the area postrema, revealed a shearing defect through the ependyma of the fourth ventricular floor into the subjacent neuropil with a disruption of axonal pathways.Conclusions. Respiratory neuronal network components lying within 2 mm of the area postrema may well have been disrupted by the caudal tears producing permanent apnea. A similar phenomenon could account for the transient or permanent postinjury apnea seen in humans with severe head injury.

Ovine pericardium as a new material for duraplasty

1996 ◽  
Vol 84 (3) ◽  
pp. 508-513 ◽  
Author(s):  
Jan Pařízek ◽  
Zdeněk Husěk ◽  
Pavel Měřička ◽  
Josef Téra ◽  
Stanislav Němeček ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Host Tissue ◽  
Γ Irradiation ◽  
Content Type ◽  
Dural Substitute ◽  
Freeze Dried ◽  
New Material ◽  
Fine Print ◽  
Scanning Electron

✓ The authors report on their 2 1/2-year clinical experience using a dural substitute, ovine pericardium, stabilized with 0.3% glutaraldehyde, flat freeze-dried, and sterilized with γ-irradiation. Packaging of the ovine pericardium in double-plastic transparent bags allows simple storage in operating rooms and the opportunity for the surgeon to choose an ideal graft according to its shape, size, and plasticity. The ovine pericardia were examined histologically and by transmission and scanning electron microscopy in their native, freeze-dried, and irradiated forms. The final product is composed solely of pericardium fibrosum interwoven with artificially formed extracellular microcavities that serve as natural pores for the ingrowth of host tissue. The surfaces of the grafts appear smooth on the inner and rough on the outer sides. Sixteen grafts were examined macroscopically at autopsy and four of these were also examined histologically to illustrate their successful healing with no adhesion to the underlying brain. As a new dural substitute, ovine pericardium proved to be superior to bovine and allogeneic pericardia because of its workability, flexibility, and reduced thickness. In a study of 120 grafts, all but one healed without complications.

Scanning electron micrographic study of vascular lesions caused by microvascular needles and suture

1980 ◽  
Vol 53 (1) ◽  
pp. 32-36 ◽  
Author(s):  
David M. Pagnanelli ◽  
T. Glenn Pait ◽  
Hugo V. Rizzoli ◽  
Arthur I. Kobrine
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Blood Vessels ◽  
Vascular Trauma ◽  
Vascular Lesions ◽  
Content Type ◽  
Fine Print ◽  
Scanning Electron

✓ The authors studied the damage to blood vessels 1 to 2 mm in diameter caused by the most commonly used types of microvascular needle. Excluding variables introduced by anastomosis, the study focused specifically on lesions attributable only to the needle and suture. Scanning electron microscopy revealed four distinct types of lesion. A theory is proposed to explain the mechanisms whereby these lesions were produced, and a needle design is recommended that may aid in minimizing vascular trauma.

An investigation of structural degradation of cerebrospinal fluid shunt valves performed using scanning electron microscopy and energy-dispersive x-ray microanalysis

2004 ◽  
Vol 100 (3) ◽  
pp. 534-540 ◽  
Author(s):  
Spyros Sgouros ◽  
Susan J. Dipple
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Cerebrospinal Fluid ◽  
Energy Dispersive ◽  
Ventricular Catheter ◽  
Content Type ◽  
X Ray ◽  
Programmable Valve ◽  
Fine Print ◽  
Scanning Electron

Object. Surveys of cerebrospinal fluid (CSF) shunts that have been removed from patients have shown that even when the ventricular catheter is the cause of the obstruction, the valve may be obstructed or underperforming. The aim of this pilot study was to investigate the degradation of shunt valve structure over time due to the deposition of debris. The findings were compared with findings in unused valves. Methods. Scanning electron microscopy was used to visualize the structures of the valves. The items that were examined included two unused and nine explanted cylindrical medium pressure valves, one unused and six explanted Delta 1.5 valves (PS Medical, Goleta, CA), and one explanted Medos Programmable valve (Codman Johnson & Johnson, LeLocle, Switzerland). The valves were cut open, disassembled, and coated in gold. The areas that were analyzed included the main valve chamber, the diaphragm unit, and the antisiphon device. For areas with abnormal deposits, energy-dispersive x-ray microanalysis was performed to establish the chemical composition of the deposits. The reference unused valves had smooth surfaces with no deposits in any areas. All explanted valves had extensive deposits in all surveyed areas. The deposits varied from small clusters of crystals to large areas that displayed a cobblestone appearance. In diaphragm valves the deposits extensively affected the surface of the diaphragm and the gap between the diaphragm and the surrounding case, where normally CSF flows; in the Medos valve the deposits affected in the spring and “staircase” unit. Deposits were present as early as 2 weeks after implantation. On some valves there was a complete film covering the entire outlet of the valve, which formed a cast inside the valve stretching from wall to wall. The deposits consisted mostly of sodium and chloride, but occasionally contained calcium. In all infected and some noninfected valves there was a significant peak of carbon, indicating the presence of protein deposits. Conclusions. It appears that the continuous flow of CSF through shunt valves causes surface deposits of sodium chloride and other crystals on all aspects of the valve, including the outlet pathways. The formation of deposits may be encouraged by the adhesive properties of the materials that constitute the valve parts.

The terminal vascular bed in the superficial cortex of the rat

1986 ◽  
Vol 65 (6) ◽  
pp. 834-846 ◽  
Author(s):  
Enrico D. F. Motti ◽  
Hans-Georg Imhof ◽  
M. Gazi Yaşargil
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Corrosion Casts ◽  
Content Type ◽  
Vascular Bed ◽  
Arteriovenous Shunts ◽  
Network Pattern ◽  
Fine Print ◽  
Scanning Electron ◽  
Terminal Vascular Bed

✓ The capillaries in the vascular bed of the rat brain have been investigated by means of scanning electron microscopy of corrosion casts. A technique is described that allowed the finer ramifications to be observed. A series of representative sites from the arteriovenous terminal pathway are described in detail. Contrary to previous reports, the dichotomic pattern of vessel distribution is shown to prevail over the network pattern. Arteriovenous shunts of discrete size were not seen.“Thoroughfare channels” could be recognized. The findings are considered in light of current physiological knowledge, and their significance for microcerebrovascular flow is indicated.

Ultrastructural changes in feline arterial endothelium following subarachnoid hemorrhage

1978 ◽  
Vol 48 (1) ◽  
pp. 49-57 ◽  
Author(s):  
Marc R. Mayberg ◽  
O. Wayne Houser ◽  
Thoralf M. Sundt
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Subarachnoid Hemorrhage ◽  
Ultrastructural Changes ◽  
Content Type ◽  
Physiological Pressure ◽  
Arterial Endothelium ◽  
Elastic Lamina ◽  
Fine Print ◽  
Scanning Electron

✓ Scanning electron microscopy of feline basilar arterial endothelium 4 hours and 1, 3, 5, and 7 days after subarachnoid hemorrhage (SAH) showed longitudinal furrows that correlated with angiographically demonstrated vasospasm. These ridges persisted after fixation at physiological pressure, and probably reflected medial contraction with undulation of the underlying elastic lamina. No change in endothelial cell morphology or thrombogenesis was observed as long as 7 days after SAH. There is no evidence from this study to suggest that ischemia from vasospasm is a product of thromboembolism from damaged endothelial surfaces.

Long-term reendothelialization of excimer laser—assisted nonocclusive anastomoses compared with conventionally sutured anastomoses in pigs

2005 ◽  
Vol 103 (2) ◽  
pp. 328-336 ◽  
Author(s):  
Henk Johan N. Streefkerk ◽  
Sanne Kleinveld ◽  
Ester L. G. E. Koedam ◽  
Marcel M. M. Bulder ◽  
Hans D. Meeldijk ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Excimer Laser ◽  
Flow Characteristics ◽  
Electron Microscopic ◽  
Content Type ◽  
Microscopic Evaluation ◽  
Fine Print ◽  
Scanning Electron

Object. In contrast to conventional anastomosis methods, the excimer laser—assisted nonocclusive anastomosis (ELANA) technique involves a platinum ring and intima—adventitia apposition with a rim of medial and adventitial layers exposed to the bloodstream. The authors assessed the reendothelialization of porcine carotid arteries through ELANA compared with conventional anastomosis by using scanning electron microscopy. Methods. In 28 pigs a bypass with one ELANA and one conventional anastomosis was made on the left common carotid artery. All patent anastomoses were evaluated intraoperatively with the aid of an ultrasonographic flowmeter and postoperatively by using scanning electron microscopy at 2 weeks, 2 months, 3 months, and 6 months thereafter. Twenty-four of 28 bypasses (48 of 56 end-to-side anastomoses) were fully patent at the time of evaluation. On scanning electron microscopic evaluation of the bypasses, all 48 patent anastomoses showed complete reendothelialization, including all 24 ELANAs in which the endothelium covered the rim and the laser-ablated edge completely. No endothelial difference was observed between conventional anastomoses and ELANAs, aside from the obvious anatomical differences like the platinum ring, which had been completely covered with endothelium. At 6 months postsurgery, remodeling of the ELANA was observed, leaving the ring covered with a layer of endothelium as the most narrow part of the anastomosis. Conclusions. In long-term experiments, ELANA allows reendothelialization comparable to that achieved with conventional anastomosis. Considering its nonocclusive and high-flow characteristics, the ELANA technique is preferable in cerebral revascularization procedures.

scholarly journals Indirect Immunodetection of Fungal Fragments by Field Emission Scanning Electron Microscopy

2015 ◽  
Vol 81 (17) ◽  
pp. 5794-5803 ◽  
Author(s):  
Komlavi Anani Afanou ◽  
Anne Straumfors ◽  
Asbjørn Skogstad ◽  
Ajay P. Nayak ◽  
Ida Skaar ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Field Emission ◽  
Polyclonal Antibodies ◽  
Detection Methods ◽  
Indoor Environments ◽  
Content Type ◽  
Freeze Dried ◽  
Scanning Electron

ABSTRACTSubmicronic fungal fragments have been observed inin vitroaerosolization experiments. The occurrence of these particles has therefore been suggested to contribute to respiratory health problems observed in mold-contaminated indoor environments. However, the role of submicronic fragments in exacerbating adverse health effects has remained unclear due to limitations associated with detection methods. In the present study, we report the development of an indirect immunodetection assay that utilizes chicken polyclonal antibodies developed against spores fromAspergillus versicolorand high-resolution field emission scanning electron microscopy (FESEM). Immunolabeling was performed withA. versicolorfragments immobilized and fixed onto poly-l-lysine-coated polycarbonate filters. Ninety percent of submicronic fragments and 1- to 2-μm fragments, compared to 100% of >2-μm fragments generated from pure freeze-dried mycelial fragments ofA. versicolor, were positively labeled. In proof-of-concept experiments, air samples collected from moldy indoor environments were evaluated using the immunolabeling technique. Our results indicated that 13% of the total collected particles were derived from fungi. This fraction comprises 79% of the fragments that were detected by immunolabeling and 21% of the spore particles that were morphologically identified. The methods reported in this study enable the enumeration of fungal particles, including submicronic fragments, in a complex heterogeneous environmental sample.

scholarly journals Increased Water Activity Reduces the Thermal Resistance of Salmonella enterica in Peanut Butter

2013 ◽  
Vol 79 (15) ◽  
pp. 4763-4767 ◽  
Author(s):  
Yingshu He ◽  
Ye Li ◽  
Joelle K. Salazar ◽  
Jingyun Yang ◽  
Mary Lou Tortorello ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Thermal Resistance ◽  
Water Activity ◽  
Salmonella Enterica ◽  
Morphological Changes ◽  
Peanut Butter ◽  
Content Type ◽  
The Difference ◽  
Scanning Electron

ABSTRACTIncreased water activity in peanut butter significantly (P< 0.05) reduced the heat resistance of desiccation-stressedSalmonella entericaserotypes treated at 90°C. The difference in thermal resistance was less notable when strains were treated at 126°C. Using scanning electron microscopy, we observed minor morphological changes ofS. entericacells resulting from desiccation and rehydration processes in peanut oil.

Morphological studies of human arteriovenous malformations

1985 ◽  
Vol 63 (3) ◽  
pp. 421-425 ◽  
Author(s):  
Peter M. Klara ◽  
Eugene D. George ◽  
Dennis E. McDonnell ◽  
Paul H. Pevsner
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Arteriovenous Malformations ◽  
Lattice Structure ◽  
Balloon Catheter ◽  
Surgical Removal ◽  
Content Type ◽  
Morphological Studies ◽  
Micro Channels ◽  
Scanning Electron

✓ Ten patients with symptomatic arteriovenous malformations (AVM's) underwent embolization with isobutyl 2-cyanoacrylate (Bucrylate) delivered via a mini-balloon catheter according to the protocol of George and Pevsner. These patients underwent surgical removal of their embolized AVM, and surgical specimens were evaluated by light and scanning electron microscopy. Ten other patients with AVM's underwent surgical resection without prior embolization, and these surgical specimens were evaluated in a similar manner. Results from this study indicate that Bucrylate incites an inflammatory response characterized by foreign-body giant cells. This reaction was present as early as 3 weeks after embolization and persisted in specimens resected almost 1 year after the last embolization. No such reaction was observed in unembolized AVM's. Both light and scanning electron microscopy demonstrated a lattice structure of the Bucrylate embolus within the AVM vessels. These studies also demonstrated micro-channels within the Bucrylate embolus and the presence of what appears to be normal red blood cells within the latticework of the embolus. Vascular endothelium not in direct contact with the Bucrylate embolus retains a normal morphology as revealed by scanning electron microscopy.

Synthesis, characterisation and tribological evaluation of surface-capped molybdenum sulphide nanoparticles as efficient antiwear bio-based lubricant additives

2017 ◽  
Vol 69 (3) ◽  
pp. 378-386 ◽  
Author(s):  
Sharul Hafiq Roslan ◽  
Sharifah Bee Abd Hamid ◽  
Nurin Wahidah Mohd Zulkifli
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Wear Scar ◽  
Gravimetric Analysis ◽  
Content Type ◽  
X Ray ◽  
Lubricant Oil ◽  
Wear Reduction ◽  
Molybdenum Sulphide ◽  
Scanning Electron

Purpose The purpose of this study is to synthesise and characterise surface-capped molybdenum sulphide (SCMS) nanoparticles using the solvothermal method and to investigate their tribological behaviour towards friction improver and wear reduction for bio-based lubricant oil additives. Design/methodology/approach The design of the experiment was to use freshly prepared molybdenum (II) acetate, thioacetamide, fatty acid and hexane as the solvent inside an autoclave vessel which is heated at high temperature and pressure. Various types of fatty acids were used as the capping agent, such as caproic, lauric, stearic and oleic acid. The SCMS nanoparticles formed were characterized by Fourier transform infrared spectroscopy, Raman spectroscopy, X-ray diffractometry, field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy and thermal gravimetric analysis. These nanoadditives were then blended into pentaerythrityl tetracaprylate/caprate ester at 0.05 Wt.% concentration. The formulated bio-based lubricant oil samples were tested for viscosity, viscosity index (VI) and density based on standard method ASTM D445 and ASTM D2270. A four-ball test was carried out for determination of coefficient of friction and wear scar diameter. The wear scar formed on the surface of the ball bearing was analysed using scanning electron microscopy. Findings The characterisation results showed that SCMS nanoparticles were successfully formed with amorphous ball-like structure, and the presence of the capping layer surrounding the nanoparticles was confirmed. Then, the formulated bio-based lubricant oil with addition of nanoadditives displays improved tribological properties in term of VI, antifriction and wear reduction. Originality/value This research provides a synthesis method of producing SCMS nanoparticles using the organomolybdenum complex as the chemical precursor through the solvothermal reaction approach. Besides that, it also gives an alternative antifriction and antiwear nanoadditive for formulation of the bio-based lubricant oil.

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