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PubMed1997

Perivascular spaces in the basal ganglia of the human brain: their relationship to lacunes.

There is evidence for lymphatic drainage of interstitial fluid from the brain along perivascular spaces in a number of mammalian species. Ultrastructural studies suggest that there are similar drainage pathways in the human cerebral cortex. Perivascular spaces in the basal ganglia, however, differ from those in the cortex in that they dilate to form lacunes and rarely accumulate beta-amyloid (amyloid angiopathy) in Alzheimer's disease; in the cortex, lacunes are rare but amyloid angiopathy is common. The aim of the present study is to compare the structure of perivascular spaces in the basal ganglia and at the anterior perforated substance with perivascular spaces in the cerebral cortex. Eight postmortem brains from patients aged 23-80 years (mean 68 y) were examined by light microscopy, by scanning and transmission electron microscopy and by direct visualisation of etched paraffin blocks. The results show that arteries in the basal ganglia are surrounded by 2 distinct coats of leptomeninges separated by a perivascular space which is continuous with the perivascular space around arteries in the subarachnoid space. The inner layer of leptomeninges closely invests the adventitia of the vessel wall and the outer layer is continuous with the pia mater on the surface of the brain at the anterior perforated substance. Veins in the basal ganglia have no outer layer of leptomeninges and thus the perivascular space is continuous with the subpial space. The anatomy of the periarterial spaces in the basal ganglia differs significantly from that in the cerebral cortex where there is only a single periarterial layer of leptomeninges. Differences in structure of perivascular spaces around arteries may reflect relative efficiencies in the drainage of interstitial fluid from different sites in the brain. Furthermore, the structure of the perivascular spaces may contribute to the relatively high frequency of lacunes in the basal ganglia, and the low frequency of amyloid angiopathy at this site in Alzheimer's disease.

Adult↗
PubMed2006

A new equal area method to calculate and represent physiologic, anatomical, and alveolar dead spaces.

BACKGROUND: Physiologic dead space is usually estimated by the Bohr-Enghoff equation or the Fletcher method. Alveolar dead space is calculated as the difference between anatomical dead space estimated by the Fowler equal area method and physiologic dead space. This study introduces a graphical method that uses similar principles for measuring and displaying anatomical, physiologic, and alveolar dead spaces. METHODS: A new graphical equal area method for estimating physiologic dead space is derived. Physiologic dead spaces of 1,200 carbon dioxide expirograms obtained from 10 ventilated patients were calculated by the Bohr-Enghoff equation, the Fletcher area method, and the new graphical equal area method and were compared by Bland-Altman analysis. Dead space was varied by varying tidal volume, end-expiratory pressure, inspiratory-to-expiratory ratio, and inspiratory hold in each patient. RESULTS: The new graphical equal area method for calculating physiologic dead space is shown analytically to be identical to the Bohr-Enghoff calculation. The mean difference (limits of agreement) between the physiologic dead spaces calculated by the new equal area method and Bohr-Enghoff equation was -0.07 ml (-1.27 to 1.13 ml). The mean difference between new equal area method and the Fletcher area method was -0.09 ml (-1.52 to 1.34 ml). CONCLUSIONS: The authors' equal area method for calculating, displaying, and visualizing physiologic dead space is easy to understand and yields the same results as the classic Bohr-Enghoff equation and Fletcher area method. All three dead spaces--physiologic, anatomical, and alveolar--together with their relations to expired volume, can be displayed conveniently on the x-axis of a carbon dioxide expirogram.

Adult↗
PubMed2002

Studies about space radiation promote new fields in radiation biology.

Astronauts are constantly exposed to space radiation of various types of energy with a low dose-rate during long-term stays in space. Therefore, it is important to determine correctly the biological effects of space radiation on human health. Studies about biological the effects at a low dose and a low dose-rate include various aspects of microbeams, bystander effects, radioadaptive responses and hormesis which are important fields in radiation biology. In addition, space radiations contain high linear energy transfer (LET) particles. In particular, neutrons may cause reverse effectiveness at a low dose-rate in comparison to ionizing radiation. We are also interested in p53-centered signal transduction pathways involved in the cell cycle, DNA repair and apoptosis induced by space radiations. We must also study whether the relative biological effectiveness (RBE) of space radiation is affected by microgravity which is another typical component in space. To confirm this, we must prepare centrifuge systems in an International Space Station (ISS). In addition, we must prepare many types of equipment for space experiments in an ISS, because we cannot use conventional equipment from our laboratories. Furthermore, the research for space radiation might give us valuable information about the birth and evolution of life on the Earth. We can also realize the importance of preventing the ozone layer from depletion by the use of exposure equipment to sunlight in an ISS. For these reasons, we desire to educate space researchers of the next generation based on the consideration of the preservation of the Earth from research about space radiation.

Cosmic Radiation↗
PubMedDate not supplied

Success of reinforced fiber material space maintainers.

PURPOSE: Various space maintainers are used in pediatric dentistry. However, their construction requires time-consuming laboratory procedures. Recently, fiber-reinforced composites (FRC) have been introduced and used in different branches of dentistry. The objective of this study was to assess long-term results for a newly developed space maintainer as an alternative procedure for practitioners. METHODS: This study used Splint-it (Jeneric/Pentron, Wallingford, Conn), a FRC, to prepare a newly developed space maintainer chairside in 1 appointment. A total of 40 space maintainers were applied to 29 children (14 girls, 15 boys) between 7 to 14 years old (mean +/- SD = 10 years, 1 month +/- 1 year, 11 months) to protect the space of their early extracted first and second primary molar teeth. For 4 children, space maintainers were prepared with artificial teeth to restore the anterior teeth loss, which occurred due to trauma. To protect the space until the fixed partial dentures were constructed, 5 space maintainers were applied to 3 children who had 2 permanent first molar teeth extracted. Appliances were observed for up to 2 years. RESULTS: Twenty-nine (73%) space maintainers were dislodged at the end of the sixth month. The space maintainers placed on primary teeth (1 or both abutments) showed the highest failure rate (94%). CONCLUSIONS: This study suggested that Splint-it space maintainers can be accepted as successful appliances only for short periods. Prolonged use of this material for space maintenance in children must be further evaluated.

Adolescent↗
PubMed2004

Public evaluation of open space in Illinois: citizen support for natural area acquisition.

Numerous studies have indicated a broad-based support for open space preservation and protection. Research also has characterized the public values and rationale that underlie the widespread support for open space. In recognition of the widespread public support for open space, various levels of government have implemented programs to provide public access to open space. There are many different types of open space, ranging from golf courses, ball parks, wildlife areas, and prairies, to name a few. This paper addresses questions related to the types of open space that should be prioritized by planners and natural resource managers. The results of this study are based on a stratified random sample of 5000 households in Illinois that were sent a questionnaire related to their support for various types of open space. Through a comparatively simple action grid analysis, the open space types that should be prioritized for public access include forest areas, stream corridors, wildlife habitat, and lakes/ponds. These were the open space types rated of the highest importance, yet were also the open space types rated the lowest in respondent satisfaction. This kind of analysis does not require the technical expertise of other options for land-use prioritizations (e.g., conjoint analysis, contingent valuation), yet provides important policy directives for planners. Although open space funds often allow for purchase of developed sites such as golf courses, ball parks, and community parks, this study indicates that undeveloped (or nature-based) open space lands are most needed in Illinois.

Adult↗
PubMed2006

Microbiology and antibiotic sensitivities of head and neck space infections of odontogenic origin.

PURPOSE: The purpose of this study is to assess the anatomical spaces and causative micro-organisms responsible for deep fascial space head and neck infections and evaluate the resistance of antibiotics used in the treatment of these infections. PATIENTS AND METHODS: A 6-year retrospective study evaluated hospital records of 103 patients. All patients in this study underwent surgical incision and drainage, received IV antibiotics, and had culture and sensitivity performed. Patient demographics reviewed were gender, age, involved fascial space(s), micro-organisms identified and antibiotic resistance from culture and sensitivity testing. RESULTS: There were 56 male (54%) and 47 (46%) female patients. The submandibular space was the most frequent location for a single space abscess (30%), followed by the buccal space (27.5%) and the lateral pharyngeal space (12.5%). Sixty-three patients presented with multiple space involvement, totaling 142 spaces involved. A total of 269 bacterial strains were isolated from 103 patients. The bacteria were found to be 63.5% gram-positive. Gram-positive cocci were isolated 57.7% of specimens and gram-negative rods were isolated in 33% of cultures. There were 178 aerobes (65.7%) and 91 anaerobes (34.3%) isolated. The most common bacteria isolated were Viridans streptococci, Provetella, Staphylococci, and Peptostreptococcus. Culture and sensitivities were reviewed on 101 patients. CONCLUSION: Patients who underwent surgical incision and drainage in the operating room had a tendency for involvement of multiple space abscesses with the submandibular space, submental, and lateral pharyngeal spaces effected most frequently. Cultures and sensitivities commonly showed greater growth in aerobes (65.7%) than in anaerobes. Gram positive cocci and gram negative rods had the greatest growth percentage in cultures.

Abscess↗
PubMed1999

Radiographic joint space in rheumatoid acromioclavicular joints: a 15 year prospective follow-up study in 74 patients.

OBJECTIVE: To evaluate radiographically the acromioclavicular joint space in patients with long-term rheumatoid arthritis (RA). METHODS: A cohort of 74 patients with RA was followed prospectively for 15 yr. At the end point, 148 shoulders were radiographed with a standard method. The acromioclavicular (AC) joint space was examined from the radiographs with a method developed previously for population studies; the joint space was measured at its superior and inferior border, and the average of the two measurements, the integral space, calculated. RESULTS: Mean AC joint space in RA patients was 4.9 (S.D. 3.7), range 0-20.5 mm; 6.2 mm (S.D. 5.1) in men and 4.5 mm (S.D. 3. 0) in women. An AC joint space wider than 7 mm in men was found in 11 (31%) out of 36 joints and wider than 6 mm in women in 17 (15%) out of 112 joints. Joint space widening was associated (r=0.87, 95% CI 0.82-0.90) with increasing destruction (Larsen grading) of the joint and it seems to be an inevitable consequence of AC joint affection in RA. Joint space widening is more progressive on the caudal side because of the nature of the erosive destruction. Degeneration with joint space narrowing was observed in 8 (11%) patients (11 joints, 7%; three bilateral). CONCLUSIONS: The largest value of the joint space may be used when evaluating rheumatoid AC joint space. In RA patients, a joint space of >7 mm in men and >5 mm in women is a sign of destructive AC joint affection.

Acromioclavicular Joint↗
PubMed1999

Effects of electrode location and spacing on phoneme recognition with the Nucleus-22 cochlear implant.

OBJECTIVE: The objective of this paper was to determine how phoneme identification was affected by the cochlear location and spacing of the electrodes in cochlear implant listeners. DESIGN: Subjects were initially programmed with the full complement of 20 active electrodes, in which each electrode was assigned to represent the output of one filter in the normal SPEAK processor. In the present study several four-electrode processors were constructed by assigning the output of more than one filter to a single electrode. In all conditions speech sounds were still analyzed into 20 frequency bands and processed according to the usual SPEAK processing strategy, but the location and spacing of the four stimulated electrode pairs were varied systematically. In Experiment I, the spacing between stimulated electrodes was fixed at 3.75 mm and the cochlear location of the four electrode pairs was shifted from the most-apical position up to 3.0 mm toward the base in 0.75 mm steps. In Experiment II, the spatial separation between the four electrode pairs (each bipolar-plus-one) was systematically changed from 1.5 mm to 4.5 mm while holding the most apical active electrode fixed. In Experiment III, the spacing of active electrodes was varied to represent equal tonotopic spacing to equal linear frequency intervals between pairs. Recognition of medial vowels and consonants was measured in three subjects with these custom four-electrode speech processors. RESULTS: In Experiment I, results showed that both vowel and consonant recognition were best when the electrodes were in the most apical locations. In Experiment II, best speech recognition occurred when electrode pairs were separated by 3 to 3.75 mm. In Experiment III, both vowel and consonant recognition scores decreased when the spacing of electrode pairs was changed from equal tonotopic spacing to equal linear frequency intervals. Overall, vowel and consonant recognition were best at the most apical electrode locations and when the spacing of electrodes matched the frequency intervals of the analysis filters. Consonant recognition was relatively robust to alterations in electrode location and spacing. The best vowel scores with four-electrode speech processors were about 10 percentage lower than scores obtained with the full 20-electrode speech processors. However, the best consonant scores with four-electrode speech processors were similar to those obtained with the full 20-electrode speech processors. Information transmission analysis revealed that temporal envelope cues (voicing and manner) were not strongly affected by changes in electrode location and spacing, whereas spectral cues, as represented by vowel recognition and consonantal place of articulation, were strongly affected. Both spectral and temporal phoneme cues were strongly affected by the degree of tonotopic warping, created by altering both the location and spacing of the activated electrodes. CONCLUSION: The cochlear location and spacing of the activated electrodes had a clear effect on phoneme recognition. Temporal cues were less affected by tonotopic shifts or linear tonotopic stretching or shrinking, but were susceptible to nonlinear tonotopic warping. Spectral cues were sensitive to all tonotopic manipulations: shifting, linear stretching, and nonlinear warping. However, the present experiments could not differentiate whether the optimal mapping between analysis frequency bands and stimulation electrodes was determined by the normal acoustic tonotopic pattern or by the pattern learned from experience with the 20-electrode implant.

Adult↗
PubMed1985

Radon entry into houses having a crawl space.

The transport of 222Rn from soil, through a vented crawl space, and into the living space of single-family residences was studied. Two houses were monitored in detail for periods of 5 and 7 weeks. With crawl space vents open, the average indoor 222Rn concentrations were 1.2 and 0.6 pCi 1.-1 (44 and 22 Bq m-3); with the vents sealed the averages rose to 2.2 and 1.0 pCi 1.-1 (81 and 37 Bq m-3). The data suggest that, of the Rn released into the crawl space from the soil beneath the house, a significant fraction, perhaps 50% or more, enters the living space. The effect of 3 meteorological parameters--wind speed, indoor-outdoor temperature difference, and rate of barometric pressure change--on Rn concentration and entry rate were examined. In 1 of the houses a higher temperature difference corresponded to a higher indoor concentration, suggesting that the increased infiltration rate is more than compensated by an increase in the Rn entry rate. On the other hand, a high wind speed tended to reduce the indoor concentration, presumably by increasing both cross-ventilation of the crawl space and the infiltration rate of the living space. Results suggest that Rn transport into the crawl space of at least 1 of the houses occurred by pressure-driven flow, rather than solely by molecular diffusion. The diffusion coefficient of 222Rn through polyethylene sheeting, such as was present on the ground beneath this house, was measured in the laboratory and found to range from 0.65 X 10(-7) cm2 s-1 at 11 degrees C to 1.6 X 10(-7) cm2 s-1 at 25 degrees C, implying that the maximum diffusive flux through the sheet was many times smaller than that necessary to account for the rate of Rn entry into the house. A third house was studied using a tracer gas injected into the crawl space at a controlled rate. The fraction of air leaving the crawl space that entered the living space ranged from 0.3 to 0.65, in good agreement with results for Rn transmission in the other 2 houses, assuming that the 222Rn flux into the crawl space was comparable to that which would have resulted from molecular diffusion from soil having a 222Rn diffusion length of 1.0 m. By sealing leaks in the floor of this house, the average infiltration rate was reduced by 25%, but the indoor concentration of the tracer gas remained constant.

Air Pollutants↗
PubMed2006

How the increase of the cervical disc space height affects the facet joint: an anatomy study.

STUDY DESIGN: In vitro study on the effect of increasing the height of the cervical disc space on the facet joint. OBJECTIVES: To demonstrate how facet joint articulation is affected by increasing the cervical disc space height. SUMMARY OF BACKGROUND DATA: A surgeon attempts to increase the disc space and inserts a larger artificial disc than normal in order to keep the intervertebral foramen open and the prosthesis stable. However, it is hypothesized by the current authors that this procedure could have an adverse effect on the facet joints. METHODS: Computerized tomography images passing through the disc space and the center of the C4-C7 facet joints (sagittal plane) were obtained from 15 cadaveric cervical spine specimens. A 1-mm incremental increase to a total 5 mm in disc space height was performed to simulate the changes seen in disc replacement. The change in the facet joint articulation overlap and space in the sagittal plane at normal and each displacement was measured. RESULTS: Each 1-mm incremental increase in disc space at C4-C5 translated to a decrease in the facet joint articulation overlap in the sagittal plane by approximately 8%. The mean facet joint space increased approximately 0.8 mm. At the C5-C6 and the C6-C7 levels, the articulation overlap decreased by approximately 7% and the facet joint space increased approximately 0.8 mm. CONCLUSIONS: There is a significant decrease of the facet joint articulation overlap in the sagittal plane and an increase in the facet joint space following an increase in the cervical disc space. The inappropriate increase of the disc space height may result in facet joint subluxation and could lead to the accelerated failure of the artificial disc.

Cadaver↗
PubMed2006

Does hard insertion and space improve shock absorption ability of mouthguard?

Mouthguards are expected to reduce sports-related orofacial injuries. Numerous studies have been conduced to improve the shock absorption ability of mouthguards using air cells, sorbothane, metal wire, or hard material insertion. Most of these were shown to be effective; however, the result of each study has not been applied to clinical use. The aim of this study was to develop mouthguards that have sufficient prevention ability and ease of clinical application with focus on a hard insertion and space. Ethylene vinyl acetate (EVA) mouthguard blank used was Drufosoft and the acrylic resin was Biolon (Dreve-Dentamid GMBH, Unna, Germany). Three types of mouthguard samples tested were constructed by means of a Dreve Drufomat (Type SO, Dreve-Dentamid) air pressure machine: the first was a conventional laminated type of EVA mouthguard material; the second was a three layer type with acrylic resin inner layer (hard-insertion); the third was the same as the second but with space that does not come into contact with tooth surfaces (hard + space). As a control, without any mouthguard condition (NOMG) was measured. A pendulum type impact testing machine with interchangeable impact object (steel ball and baseball) and dental study model (D17FE-NC.7PS, Nissin, Tokyo, Japan) with the strain gages (KFG-1-120-D171-11N30C2: Kyowa, Tokyo, Japan) applied to teeth and the accelerometer to the dentition (AS-A YG-2768 100G, Kyowa) were used to measure transmitted forces. Statistical analysis (anova, P < 0.01) showed significant differences among four conditions of NOMG and three different mouthguards in both objects and sensor. About acceleration: in a steel ball which was a harder impact object, shock absorption ability of about 40% was shown with conventional EVA and hard-insertion and about 50% with hard + space. In a baseball that was softer compared with steel ball, a decrease rate is smaller, reduction (EVA = approximately 4%, hard-insertion = approximately 12%, hard + space = approximately 25%) was admitted in the similar order. A significant difference was found with all the combinations except for between EVA and hard-insertion with steel ball (Tukey test). About distortion: both buccal and lingual, distortions had become small in order of EVA, hard-insertion, and hard + space, too. The decrease rate is larger than acceleration, EVA = approximately 47%, hard-insertion = 80% or more, and hard +space = approximately 98%, in steel ball. EVA = approximately 30%, hard-insertion = approximately 75%, and hard + space = approximately 98% in baseball. And a significant difference was found with all the combinations (Tukey test). Especially, hard + space has decreased the distortion of teeth up to several percentages. Acceleration of the maxilla and distortions of the tooth became significantly smaller when wearing any type of mouthguard, in both impact objects. But the effect of mouthguard was clearer in the distortion of the tooth and with steel ball. Considering the differences of mouthguards, the hard-insertion and the hard + space had significantly greater buffer capacity than conventional EVA. Furthermore, hard + space shows quite high shock absorption ability in the tooth distortion. Namely, hard + space has decreased the distortion of teeth up to several percentages in both impact objects.

Acceleration↗
PubMed2003

Impact of early postweaning growth rate as affected by diet complexity and space allocation on subsequent growth performance of pigs in a wean-to-finish production system.

The objective was to evaluate the effect of restricted early postweaning growth rate due to diet complexity, pen space, or both on subsequent growth to market in a wean-to-finish system. Pigs (n = 1,728) were used in a randomized block design with a 2 x 2 factorial arrangement of treatments: 1) diet complexity (Complex vs Simple) and 2) space allocation (Unrestricted vs Restricted). Treatments were imposed for the first 8 wk after weaning (period 1) and growth was measured from weaning (5.0 +/- 0.01 kg body weight; 15 d of age) to the end of wk 23 postweaning. The Simple diet was based on corn-soybean meal with minimal inclusion of milk products, processed cereals, and animal protein-based ingredients compared to the Complex diet. Floor and feeder-trough spaces were 0.63 m2 and 4 cm and 0.21 m2 and 2 cm per pig for Unrestricted and Restricted space treatments, respectively. From the end of wk 8 to end of wk 23 (period 2), pigs on all treatments had the same floor and feeder spaces and were fed common diets. There was no interaction (P > 0.05) between diet and space treatments. In period 1, Simple diets resulted in similar average daily feed intake (ADFI; 639 vs 650 +/- 5.4 g; P > 0.05), but lower average daily gain (ADG; 408 vs 424 +/- 3.8 g; P < 0.01) and gain:feed ratio (0.64 vs 0.65 +/- 0.002; P < 0.001), and lighter body weight (2.8%; P < 0.01) compared to the Complex diets. In period 2, growth was not affected (P > 0.05) by previous diet complexity, and pig body weight was similar (114.4 vs 114.4 +/- 0.37 kg, P > 0.05) at the end of wk 23. In period 1, pigs with Restricted space had lower ADG (398 vs 434 +/- 3.8 g; P < 0.001), ADFI (621 vs 668 +/- 5.4 g; P < 0.001), and gain:feed ratio (0.64 vs 0.65 +/- 0.002; P < 0.01), and were lighter at the end of wk 8 (6.5%; P < 0.001) than those with Unrestricted space. However, in period 2, pigs with Restricted space had higher (P < 0.01) ADG (3%), ADFI (2%), and gain:feed ratio (3%) than those with Unrestricted space, and body weight was similar (114.5 vs 114.3 +/- 0.37 kg; P > 0.05) at end of wk 23. Carcass backfat and loin-eye depth at market body weight were influenced by neither diet nor space treatment. Using a simple diet program and restricted space allowance immediately postweaning resulted in a lower early growth rate, but had no impact on pig body weight or carcass measures at market.

Animal Feed↗
PubMedDate not supplied

Morphometric comparison of endolymphatic and perilymphatic spaces in human temporal bones.

To measure the endolymphatic and perilymphatic spaces, we used human temporal bones (horizontal serial sections) under two selection criteria: absence of otological pathology, and absence of artifact in the membranous labyrinth (boundary between endolymphatic and perilymphatic spaces) maintaining an intact structural integrity. Under magnified projection, the area of scala tympani, scala vestibuli, scala media, vestibular endolymphatic space, and vestibular perilymphatic space were measured separately, using a microcomputer digitizing tablet. Three repeated measurements were obtained and averaged. The mean total labyrinthine fluid space was 204.5 mm3; the mean total endolymphatic space was 38.1 mm3 and mean total perilymphatic space 166.4 mm3. The mean total vestibular fluid space was 120.9 mm3 and mean total cochlear fluid space 83.6 mm3. In the vestibule, the perilymphatic space occupied 74.8%, and the endolymphatic space, 25.2%, whereas 90.8% of the cochlear fluid space was occupied by perilymph.

Adult↗
PubMed2002

The effect of letter spacing on reading speed in central and peripheral vision.

PURPOSE: Crowding, the adverse spatial interaction due to proximity of adjacent letters, has been suggested as an explanation for slow reading in peripheral vision. The purpose of this study was to examine whether reading speed can be improved in normal peripheral vision by increasing the letter spacing. Also tested was whether letter spacing imposes a different limit on reading speed of small versus large print. METHODS: Six normal observers read aloud single, short sentences presented on a computer monitor, one word at a time, by rapid serial visual presentation (RSVP). Reading speeds were calculated based on the RSVP exposure durations yielding 80% correctly read words. Letters were rendered in Courier, a fixed-width font. Testing was conducted at the fovea, 5 degrees and 10 degrees in the inferior visual field. The critical print size (CPS) was first determined for each observer by measuring reading speeds for four print sizes, using the standard letter spacing (center-to-center separation of adjacent letters; standard Courier spacing: 1.16 times the width of the lowercase x). Text was then presented at 0.8 x or 1.5x CPS, and reading speed was measured for five letter spacings, ranging from 0.5 times to 2 times the standard spacing. RESULTS: As expected, reading speed was highest at the fovea, decreased with eccentricity, and was faster for the larger print size. At all eccentricities and for both print sizes, reading speed increased with letter spacing, up to a critical letter spacing, and then either remained constant at the same reading speed or decreased slightly for larger letter spacings. The value of the critical letter spacing was very close to the standard letter spacing and did not depend on eccentricity or print size. CONCLUSIONS: Increased letter spacing beyond the standard size, which presumably decreases the adverse effect of crowding, does not lead to an increase in reading speed in central or peripheral vision.

Adult↗
PubMed2002

[Influence of the height of the joint space on the three-dimensional kinetics of total knee prostheses and behavior of the lateral ligaments: an in vitro study].

PURPOSE OF THE STUDY: The level of the joint space can be modified after implantation of a total knee prosthesis. Likewise, ligament balance is a cardinal point of the surgical technique. The purpose of this in vitro work was to study the influence of the position of the distal tibiofemoral joint space after implantation of a total knee prosthesis on the three-dimensional kinetics of the knee joint and on the behavior of the lateral ligaments. MATERIAL AND METHOD: Total knee arthroplasty (TKA) with a posterior stabilized prosthesis was performed on seven fresh-frozen cadaver specimens. A specially-designed experimental device was used to achieve continuous knee motion simulating hip flexion from a vertical position. The Vicon optoelectronic system was used to record the femorotibial and femoropatellar kinematics in three dimensions. Two electronic goniometers were positioned on the insertions of the lateral ligaments to measure ligament displacements during knee movements. Five configurations were recorded on each knee: healthy knee, same knee after TKA, and 2-mm and 4-mm upward displacement of the prosthetic distal tibiofemoral joint space. Ligament balance at extension was preserved in all configurations. The kinematic curves obtained were compared with the coefficient of multiple correlation. RESULTS: Changing the position of the joint space had a significant effect on the kinematics of the patella (rotation and abduction-rotation) but did not have a significant effect on the femorotibial kinematics. Variations in the length of the lateral ligaments were of small amplitude. Lowering the joint space led to laxity at flexion. Raising the joint space tightened the ligaments at flexion. DISCUSSION: These results confirm our clinical impression when the level of the distal femur cut is set to achieve tension on the ligaments at knee extension. If the joint space is lowered, i.e. with a more sparing distal femur cut, the prosthesis takes up less space during flexion, leading to laxity at flexion. If the joint space is raised, i.e. with an excessive distal femur cut, the prosthesis takes up more space during flexion, tightening the lateral ligaments. CONCLUSION: The position of the joint space must be rigorously reproduced during TKA not only to maintain correct femorotibial kinematics, but most importantly to preserve patellar kinematics and proper behavior of the lateral ligaments. Ideally, the height of the joint space should be restored first, followed by control of the ligament balance. An over- or undercut of the femur can lead to defective femoropatellar kinematics and ligament tension at flexion despite good ligament balance at extension. In addition, ligament balance should not be achieved by displacing the tibial cut or by modifying the thickness of the tibial component, which would have an effect not only at extension but also at flexion.

Anthropometry↗
PubMed1989

[Fine morphology of the lymphatics and tissue spaces in the liver parenchyma in man and its significance in hepatobiliary surgery].

The authors investigated the intrahepatic lymphatic vessels of the human liver under a light and electron microscope. The histological material was obtained from 10 patients operated on account of simple cholecystolithiasis. The beginnings of the lymphatic capillaries are in the periphery of the perilobular connective tissue of the portobiliary space in the vicinity of openings of Mall's space. Communication between lymphatic capillaries and Mall's space was not proved. The fine structure of the openings in Mall's space with numerous microvilli of hepatocytes pointing towards the perilobular connective tissue were described. Mall's space communicates and is interconnected in a multiple way with intercellular spaces between neighbouring hepatocytes. Here also the plasmalemma of hepatocytes forms a system of microvilli which form the borderline of the interhepatocytic space. The ultrastructure of both systems of spaces corresponds to the pattern on the hepatocyte surface in Disse's perisinusoid space. The cell population of hepatocytes holds a special position because it lacks the lamina basalis as a selective barrier against the connective tissue interstitium. This structural specificity indicates the extensive and rapid transport of lymph via the perisinusoid Disse spaces into the blood stream of the hepatic sinusoids, also lacking lamina basalis. Mall's space and the system of interhepatocytic spaces form a continuous system which is in close but not direct contact with the incipient intrahepatic lymphatic capillaries.

Adult↗
PubMed1997

[The nasopharynx and deep spaces of the face: anatomy and applications to pathology].

Deep facial spaces are anatomically delineated by the layers of deep cervical fascia. They are located between the skull base and the hyoid bone. Each space contains specific anatomic structures, which can be responsible for specific pathologic processes. Deep facial spaces can be divided in two medial odd spaces (pharyngeal mucosal and retropharyngeal spaces), and in three lateral even spaces (retrostylian, prestylian, and masticator spaces). The dividing of these core tissues are useful for the analysis of the lesions found in this area. CT scan and MRI (with axial and coronal views) provide precise analysis. The main lesions are: -medially, adenoidal hyperplasias and squamous cell carcinomas (pharyngeal mucosal space), adenopathies and abscess (retropharyngeal space). -laterally, salivary tumors (prestylian space), adenopathies, schwannomas and paragangliomas (retrostylian space). Masticator space (and especially pterygopalatine fossa) is an important way of communication and is often involved by the extension of locoregional pathologic processes.

Adenoids↗
PubMed1998

[Evaluation of the usefulness of ultrasonic examination of the pre-epiglottic space in patients with laryngeal carcinoma].

The subject of the paper was to assess the usefulness of ultrasound examination of preepiglottic space (Fig. 1) in laryngeal carcinoma. Importance of oncological state of HTE space for the choice of treatment was presented. On the basis of 73 patients having laryngeal cancers with different location and progression (Tab. 1) USG, CT imaging and postoperative histopathological investigation were compared. USG investigation of HTE space was performed with ultrasonograph SSA-250 A (Toshiba) at the frequency of transducer 7.5 MHz. In this paper, the method of USG investigation of preepiglottic space was presented. CT examination of HTE space was performed with GE CT Max-640. On the basis of examinations in a group of 16 healthy persons, characteristics of USG image of normal HTE space was established (Fig. 2). That provided a point of reference involving the assessment of USG image of HTE space in patients with laryngeal cancer (Fig. 3). Results of USG, CT (Fig. 4, Fig. 5) and postoperative histopathological examinations were compared. In 86% of cases agreement between USG and histopathological examinations was noted as was between USG and CT. Results of assessment of USG investigation were: sensitivity 90%, specificity 78%, efficiency 86%. Attention was focused on emphatic predisposition of cancer localized on subhyoid part of epiglottis to penetrate into HTE space. Among the cases with this localization of cancer, in 80% neoplastic infiltration was observed in histopathological investigation of HTE space. In this paper causes of false results were analysed. In USG 6 cases were false positive and 3 false negative. In CT 7 cases were false positive and 2 false negative. Reasons of difficulties in interpretation were: advanced laryngeal carcinoma, short and thick neck, changes in neck spine. Established results have shown that USG investigation of preepiglottic space is valuable method and very useful in preoperative diagnosis in laryngeal cancer. It properly helps to assess oncological state of HTE space. This method makes it possible to find even minor changes in HTE space (0.5 cm). It should be here added that the method is easily applicable, reproducible, and in comparison with CT much cheaper and safe with regard to health.

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