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At least 901 records · Page 50Linked to original sources
PubMed1987

Morphology of the meniscotemporal part of the temporomandibular joint and its biomechanical implications.

The temporomandibular joint is a diarthrosis. It has classically been referred to as being a condylar, and functionally as a double condylar joint. We have used the moiré topographical technique to study the morphology of the pars suprameniscalis or meniscotemporalis of the joint. The findings show that this pars suprameniscalis could be classified as a saddle joint. The biomechanical implications are also discussed.

Humans↗
PubMed1993

Morphometric and stereological study of the glandular epithelium of the seminal vesicle of castrated guinea pigs treated with 17 beta-oestradiol benzoate.

Morphometric and stereological data are presented showing that the average thickness of the glandular epithelium (including secretory and basal cells together with intercellular spaces) of the seminal vesicle of the guinea pig increased significantly after oestradiol administration when compared with castrated controls. The increase in thickness was accompanied by a significant increase in the volume density of intercellular spaces. There were significant decreases in volume, surface and numerical densities of the secretory cell nuclei with respect to the glandular epithelium. The increase in the volume and surface densities of the secretory cell nuclei with respect to the average secretory cell was due to the significant increase in the average volume of the secretory cell. The increase in the mean volume of secretory cells was the result of a significant increase in the average cytoplasmic volume. In comparison with castrated controls, the structural data of cytoplasmic organelles also showed significant increases in total volume and surface area of granular endoplasmic reticulum per average secretory cell following oestradiol administration. This was accompanied by a significant increase in the total volume of Golgi cisternae per cell. The increase in the cytoplasmic volume of secretory cells after oestradiol treatment may be the result of an increase in number of organelles responsible for protein synthesis. The present study has provided quantitative evidence that the secretory function of the seminal vesicle of castrated guinea pigs may have been stimulated after oestradiol administration, which cannot be easily detected in a qualitative manner.

Animals↗
PubMed1993

Morphology and stereology of the female canine urethra correlated with the urethral pressure profile.

Perfusion-fixed urethrae of five sexually intact nulliparous female beagles in anestrus, between 2 and 3 years of age, were morphologically and morphometrically investigated. Absolute and relative volumes of different tissue components were stereologically estimated per urethral quarter. A discrete smooth muscle sphincter could neither be identified in the bladder neck nor in the urethra. However, the circularly arranged smooth muscle fibers in the proximal half of the urethra were regarded as being capable of sphincteric function. The connective tissue, composed of collagenous and longitudinally orientated numerous elastic fibers, accounted for the most predominant constituent. It comprised 77.3 to 78.2% of the total volume in the proximal three urethral quarters. The vascular plexus was most prominently developed in the proximal two urethral quarters, and its relative and absolute volumes significantly exceeded those of the third quarter. The discovered direct connections between small arteries and the sinusoids of the vascular plexus emphasize its importance as a major contributory component to urinary continence. The striated musculus urethralis was essentially confined to the distal half of the urethra and most strongly developed in the fourth quarter, where it surrounded the urethra transversely at its ventral and lateral aspects. The caudal muscle fibers continued dorsally to the vagina. A transitional epithelium bounded the urethral lumen. Its superficial cell layer progressively flattened towards the external urethral orifice, changing into a stratified squamous lining as also seen in the vestibulum. Recorded pressures, or pressure changes, could neither be correlated with volumes nor with morphology of particular tissue elements in the different urethral quarters.

Animals↗
PubMed1997

The potentially best stereographic presentation of the plastinated anatomical specimen.

Volumegraph, which is an improved version of the parallax panoramagram, has been studied as a method of stereophotography of a plastinated human body specimen. The volumegraph provides a steric view of the specimen in a natural color appearance. The potential advantages in using the volumegraph for the presentation of anatomical specimens are discussed taking account of its technical details.

Anatomy↗
PubMed1989

Effect of systemic fluoride on rat molar morphology. Stereophotogrammetric analysis.

Female Sprague-Dawley rats were divided into three groups. All three groups were given the same solid diet (with 1.6 ppm F). Group I was given deionized water, group II drank water with 5 ppm fluoride added, and group III had 50 ppm fluoride added. All females were mated with the same male. The pups were sacrificed at 28 days, and the mandibles were removed and cleaned. Three-dimensional representations of the occlusal surfaces of the 1st and 2nd mandibular molars were reproduced via computer-digitized images using stereophotogrammetry. Fissure depths and widths were measured, and 'volumes' of the fissures were computed. The fissure widths, depths, and volumes were compared statistically using unpaired t tests between groups (p less than 0.05). There were significant differences in fissure depth between groups I and II and between groups I and III. For fissure volumes, significant differences were found between groups I and III. The width of the fissure and the overall tooth size were not significantly different between fluoride-treated groups. Standardization showed a reproducibility to within +/- 40 mm with the stereophotogrammetric method.

Animals↗
PubMed1995

Relationship between external and histologic features of progressive stages of caries in the occlusal fossa.

The material comprised 140 extracted maxillary third molars. The central fossa area was examined with a stereomicroscope (SM) (x16) and macroscopically (M) under standardized conditions after cleaning and air-drying. Signs of caries were classified using a detailed scoring system involving 12 (SM) and 8 (M) classification criteria, ranging from 'sound' to 'cavitation with dentine involvement'. Six radiographic scores were used in the classification. Sections 250 microns in thickness were cut in buccolingual direction through the central fossa, and the fossa section with the most extensive stereomicroscopic changes was selected for histologic examination (x16). The histologic enamel and dentine changes were classified independently using 9 and 7 scores, respectively. The correlation between SM and the histologic enamel changes (HE scores) in terms of progressive demineralization and destruction were highly correlated (rs = 0.90). Dentinal changes were also highly correlated with enamel changes (rs = 0.85). The histologic classifications in conjunction with the macroscopical observations made it possible to demonstrate a clear relationship between the external degree of caries progression and the internal enamel and dentine reactions. The data did not support routine usage of radiographic examination for occlusal caries diagnosis.

Adolescent↗
PubMed1976

Cardiac imaging using a phased array ultrasound system. II. Clinical technique and application.

A new two-dimensional ultrasound imaging system capable of producing high resolution tomographic images of the heart in real time has been developed. This system relies on phased array principles to rapidly steer the ultrasound beam through the structures under investigation. A hand-held linear array of 16 ultrasound transducers with overall dimensions of 14 mm at the site of contanct may be readily manipulated to image various cardiac structures. The resulting images are displayed in a circular sector format, 60 degrees in azimuth and typically 15 cm in range. At his maximum range, image frames consisting of 256 lines are generated at the rate of 20 frames/second. High azimuthal resolution throughout the field of view is assured by a focused transmit beam and by sweeping the focus of the receiver is synchrony with the range of returning echoes. Azimuthal resolution varies from 2 to 5 mm throughout the field of view while range resolution is 1.5 mm. This imaging system has proven particularly useful for the delineation of left ventricular spatial geometry by the identification of endocardium, myocardium, papillary muscles and interventricular septum. High quality images of anterior and posterior mitral leaflets, aortic root and aortic leaflets as well as left atrium and other cardiac structures have been obtained.

Echocardiography↗
PubMed2006

The infection algorithm: an artificial epidemic approach for dense stereo correspondence.

We present a new bio-inspired approach applied to a problem of stereo image matching. This approach is based on an artificial epidemic process, which we call the infection algorithm. The problem at hand is a basic one in computer vision for 3D scene reconstruction. It has many complex aspects and is known as an extremely difficult one. The aim is to match the contents of two images in order to obtain 3D information that allows the generation of simulated projections from a viewpoint that is different from the ones of the initial photographs. This process is known as view synthesis. The algorithm we propose exploits the image contents in order to produce only the necessary 3D depth information, while saving computational time. It is based on a set of distributed rules, which propagate like an artificial epidemic over the images. Experiments on a pair of real images are presented, and realistic reprojected images have been generated.

Algorithms↗
PubMed1990

Glottographic analysis of phonation in the excised canine larynx.

An excised canine larynx model of phonation was developed to assess the effect of vocal fold length and tension on glottographic waveforms. The canine larynx in an experimentally produced phonatory model vibrated in a two-mass system comparable to human voice production. The recorded glottographic waveforms for the excised canine larynx were similar to signals recorded in humans in the chest register. Vocal fold length, longitudinal vocal fold tension, glottic width, and airflow rate were varied while simultaneous measurements were made of the subglottic pressure, electroglottographic signal, photoglottographic signal, and acoustic signal. The model used is illustrated and discussed, with emphasis on the method of simulating the actions of all of the intrinsic laryngeal muscles, including the thyroarytenoid muscles. The open quotient and speed quotient, calculated from the glottographic signals, were dependent on vocal fold length and tension and glottic width. These results suggest that glottographic analysis, particularly speed quotient and open quotient, provide valuable information on vocal fold vibration during phonation, and may be important in assessing laryngoplasty procedures.

Animals↗
PubMed1988

Measurement of gingival swelling from dental casts by generation of a moiré pattern with laser light.

The aim of the study was to develop a sensitive measuring method enabling direct evaluation of gingival swelling to be made as registered on dental casts. On two separate occasions, when different degrees of severity of gingival inflammation were present in the same subject, reversible hydrocolloid impressions were taken of the mandible. The casts obtained were located successively in identical three-dimensional relationships in a field of interference fringes generated by two intersecting beams of collimated helium-neon laser light, and were photographed. The evaluation of the moiré pattern obtained directly by superimposition of the two images of the surface studied indicated that a decrease in gingival height of 0.38 mm in the direction of the camera had occurred between the two occasions. The use of a computer-based image-processing system considerably improved the visibility of the pattern. The reproducibility of the impression technique, as well as the relocation and superimposing techniques, proved satisfactory at the moiré resolution used (0.19 mm). The method has potential application in clinical experimental research, and therefore warrants further evaluation.

Adult↗
PubMed1989

Estimation of chronological age from different body segments in boys and girls aged 4-19 years, using anthropometric and photogrammetric techniques.

Data obtained from measuring different body segments (stature, sitting height, upper limb, upper arm, forearm, leg, hand and foot length), were used to construct equations for estimating the chronological age of children with unknown date of birth. About 18,510 sets of measurements were taken on boys and 11,568 sets on girls. All were healthy British children aged 4-19 years and participating in three longitudinal studies at the Department of Growth and Development, Institute of Child Health, University of London. Both anthropometric and photogrammetric techniques of measurement were used to construct 35 anthropometric and 49 photogrammetric equations using the multiple linear regression model. These equations give the most likely estimated value for age together with its error. The accuracy of the equations and its applicability both on live children and on postmortem material is discussed.

Adolescent↗
PubMed1987

Measurement and prediction of progress in delayed wound healing.

Thirty chronic leg ulcers have been studied under controlled conditions until complete healing occurred. Measurement was performed weekly using a computer-linked stereocamera which is capable of measuring skin defects noninvasively with errors of less than 2%. There was a significant difference in healing rate for the first two weeks between clean ulcers entering the trial directly and ulcers admitted first for cleansing before joining the trial. The difference suggests that the weekly healing rate of an ulcer may take up to 2 weeks to respond to a new form of treatment. Absolute ulcer size, change in ulcer size and rate of epithelial migration did not correlate well with time to complete healing, but percentage change in area in the third week was found to be the parameter which gave the earliest close correlation with time to complete healing. Using this parameter, on the data available it was found that time to complete healing could be predicted to within one week for 50% of the ulcers, making this a simple and useful early predictor of treatment efficiency.

Humans↗
PubMedDate not supplied

Moire topography in facial plastic surgery.

Moire topography, a form of biostereometrics, is a technique that provides one-step contour maps. Facial measurements so obtained may be useful in reconstructive surgery.

Face↗