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PubMed2006

Competency in cardiac examination skills in medical students, trainees, physicians, and faculty: a multicenter study.

BACKGROUND: Cardiac examination is an essential aspect of the physical examination. Previous studies have shown poor diagnostic accuracy, but most used audio recordings, precluding correlation with visible observations. The training spectrum from medical students (MSs) to faculty has not been tested, to our knowledge. METHODS: A validated 50-question, computer-based test was used to assess 4 aspects of cardiac examination competency: (1) cardiac physiology knowledge, (2) auditory skills, (3) visual skills, and (4) integration of auditory and visual skills using computer graphic animations and virtual patient examinations (actual patients filmed at the bedside). We tested 860 participants: 318 MSs, 289 residents (225 internal medicine and 64 family medicine), 85 cardiology fellows, 131 physicians (50 full-time faculty, 12 volunteer clinical faculty, and 69 private practitioners), and 37 others. RESULTS: Mean scores improved from MS1-2 to MS3-4 (P = .003) but did not improve or differ significantly among MS3, MS4, internal medicine residents, family medicine residents, full-time faculty, volunteer clinical faculty, and private practitioners. Only cardiology fellows tested significantly better (P<.001), and they were the best in all 4 subcategories of competency, whereas MS1-2 were the worst in the auditory and visual subcategories. Participants demonstrated low specificity for systolic murmurs (0.35) and low sensitivity for diastolic murmurs (0.49). CONCLUSIONS: Cardiac examination skills do not improve after MS3 and may decline after years in practice, which has important implications for medical decision making, patient safety, cost-effective care, and continuing medical education. Improvement in cardiac examination competency will require training in simultaneous audio and visual examination in faculty and trainees.

Cardiology↗

PubMed1979

Three-dimensional structure of the central mitotic spindle of Diatoma vulgare.

Central mitotic spindles in Diatoma vulgare have been investigated using serial sections and electron microscopy. Spindles at both early stages (before metaphase) and later stages of mitosis (metaphase to telophase) have been analyzed. We have used computer graphics technology to facilitate the analysis and to produce stereo images of the central spindle reconstructed in three dimensions. We find that at prometaphase, when the nuclear envelope is dissassembling, the spindle is constructed from two sets of polar microtubules (MTs) that interdigitate to form a zone of overlap. As the chromosomes become organized into the metaphase configuration, the polar MTs, the spindle, and the zone of overlap all elongate, while the number of MTs in the central spindle decreases from greater than 700 to approximately 250. Most of the tubules lost are short ones that reside near the spindle poles. The previously described decrease in the length of the zone of overlap during anaphase central spindle elongation is clearly demonstrated in stereo images. In addition, we have used our three-dimensional data to determine the lengths of the spindle MTs at various times during mitotis. The distribution of lengths is bimodal during prometaphase, but the short tubules disappear and the long tubules elongate as mitosis proceeds. The distributions of MT lengths are compared to the length distributions of MTs polymerized in vitro, and a model is presented to account for our findings about both MT length changes and microtubule movements.

Anaphase↗

PubMed1997

Three-dimensional visualization and quantification of the benzodiazepine receptor population within a living human brain using PET and MRI.

Positron emission tomography (PET) in combination with receptor-selective high-affinity radioligands allows the characterization of neuroreceptor distributions in the living human brain. Thus far, the visualization and quantification of receptors with PET have been limited to series of two-dimensional (2D) image planes of the anatomic receptor distribution. The development of high-resolution PET has increased the number of planes to approximately 50, supplying an excessive amount of image information from a single experiment. The inherent limitations of 2D techniques make them insufficient to apprehend and efficiently analyze this cumbersome amount of data. In the present communication we describe procedures to visualize and quantify in three dimensions (3D) the total image information from the compound set of 47 2D planes of a PET experiment using commercially available software. Three-dimensional computer graphic and volume rendering techniques were used to analyze and display the results. For the experimental application the benzodiazepine (BZ) antagonist [11C]flumazenil was used as radioligand to visualize the BZ receptor (BZR) population in the brain of a healthy human subject. Three-dimensional images of the radioligand binding receptor population were displayed with regard to volume and form in relation to the corresponding anatomic structures in the brain reconstructed from MR images. The volume-rendering technique allowed the inspection of PET signals representing BZR populations in the interior of the hemisphere as viewed from the medial projection. Thresholding and seeding techniques were used to define volumes and quantities. Using the PET data and volume rendering, the total amount of cerebral BZRs (NCerebrum) and the apparent volume they take into account (V(BZR, Cerebrum)app) could he calculated for the first time using an automated procedure. The cerebrum of the healthy subject contained 17.6 nmol of BZRs in a volume of approximately 1.25 L. The principles and application of the technical development described offer new dimensions to clinical neuroscience and should be practically useful for automated quantitative determination of neuroreceptor number in brain regions of patients with neuropsychiatric disorders and in relation to drug treatment.

Adult↗

PubMed2000

Simulation of the surgical manipulation involved in clipping a basilar artery aneurysm: concepts of virtual clipping. Technical note.

Despite recent advances in three-dimensional imaging based on a voxel-rendering method, these techniques do not simulate the morphological changes that occur during surgery. The authors' goal was to develop a computer-graphics model to simulate the manipulation that occurs during surgery when clipping a cerebral aneurysm. The authors developed an application program to interpolate the contours of models of an artery and an aneurysm clip. The center of displacement was determined inside the arterial model. The directions of displacement were changed to simulate saccular and broad-neck aneurysms, and the intensity of displacement was calculated by using a cosine-based formula. The morphological changes in a saccular aneurysm that may occur during clipping were calculated in x, y, and z coordinates by using sine- and cosine-based formulas. Clip movement was integrated with the aneurysm model, thus simulating the manipulation used during clipping of a cerebral aneurysm. Surgery performed to clip a basilar artery (BA) aneurysm via the transsylvian approach was simulated, in which displacement of the internal carotid artery and clipping of the BA aneurysm were necessary. The movements of an aneurysm clip and clip applicator were designed to represent those occurring when a surgeon actually manipulates a BA aneurysm. The authors have named this methodological tool "virtual clipping." Use of this tool would assist the preoperative choice of clipping style and selection of the best clip.

Basilar Artery↗

PubMed1989

Computer modeling from solution data of spinach chloroplast and of Xenopus laevis somatic and oocyte 5 S rRNAs.

Detailed atomic models of a eubacterial 5 S rRNA (spinach chloroplast 5 S rRNA) and of a eukaryotic 5 S rRNA (somatic and oocyte 5 S rRNA from Xenopus laevis) were built using computer graphic. Both models integrate stereochemical constraints and experimental data on the accessibility of bases and phosphates towards several structure-specific probes. The base sequence was first inserted on to three-dimensional structural fragments picked up in a specially devised databank. The fragments were modified and assembled interactively on an Evans & Sutherland PS330. Modeling was finalized by stereochemical and energy refinement. In spite of some uncertainty in the relative spatial orientation of the substructures, the broad features of the models can be generalized and several conclusions can be reached: (1) both models adopt a distorted Y-shape structure, with helices B and D not far from colinearity; (2) no tertiary interactions exist between loop c and region d or loop e; (3) the internal loops, in particular region d, contain several non-canonical base-pairs of A.A, U.U and A.G types; (4) invariant residues appear to be more important for protein or RNA binding than for maintaining the tertiary structure. The models are corroborated by footprinting experiments with ribosomal proteins and by the analysis of various mutants. Such models help to clarify the structure-function relationship of 5 S rRNA and are useful for designing site-directed mutagenesis experiments.

Animals↗

PubMed2004

Preserving and sharing examples of anatomical variation and developmental anomalies via photorealistic virtual reality.

Computer graphics technology has made it possible to create photographic-quality virtual specimens from real anatomical material. One technique for doing this, QuickTime Virtual Reality (QTVR), results in virtual specimens that are easily shared on the Internet and displayed as standalone entities or incorporated into complex programs or Web sites. A compelling use of this technology is the sharing of rare specimens such as unusual variations, developmental anomalies or gross pathology. These types of specimens have traditionally been confined to anatomical museums, but could serve a much more useful existence as freely shared virtual specimens. An example presented here is a relatively rare developmental defect in the embryonic aortic arches that results in a right-sided aortic arch coursing posterior to the trachea and esophagus. In a time of ever increasing restraints on the practical side of anatomy education, an Internet-based library of human variation and other rare specimens would be a useful supplement to students' limited exposure to the human body. Since the discovery and preparation of specimens would be the rate-limiting step in producing such a collection, we propose the establishment of a center for virtual specimen creation and preservation through a cooperative effort by gross anatomists and pathologists in contributing the source material. This collection, a work in progress, is available at www.anatomy.wright.edu/qtvr.

Anatomy↗

PubMed1998

Peripheral and central colour contrast sensitivity in diabetes.

PURPOSE: To study the influence of diabetes, with or without early retinopathy, on peripheral and central colour contrast sensitivity. METHODS: The study included 32 patients with diabetes mellitus type II and 47 age-matched normals. The patients were divided into three sub-groups. 1. Diabetics with no retinopathy (on photographs or biomicroscopy). 2. Diabetics with microaneurysms only. 3. Diabetics with microaneurysms and hard exudates. Colour contrast sensitivity was measured with a computer graphics system along the protan, deutan and tritan axes. RESULTS: The peripheral colour contrast thresholds were significantly elevated for all axes when comparing the group with microaneurysms and exudates to normals. There were also significant differences between the group with microaneurysms and hard exudates and the two other diabetic groups, respectively, but only for the tritan axis. Diabetics with no retinopathy or with microaneurysms only did not differ significantly from normals. The central colour contrast thresholds showed significant differences between normals and the group with microaneurysms, but only for the protan and deutan axes. There were significant differences for all three axes between normals and the group with microaneurysms and hard exudates. There were also significant differences between the group with microaneurysms and hard exudates and the two other diabetic groups, but only for the tritan axis. Diabetics with no retinopathy did not differ significantly from normals. CONCLUSION: Peripheral colour contrast sensitivity was affected by low-grade diabetes type II retinopathy. This finding has to be considered if the method is to be used in screening for glaucoma. The central colour contrast sensitivity test seems to correlate to the degree of retinopathy and thereby perhaps provides a new screening method for diabetes retinopathy. Further studies are required in order to evaluate such a possibility.

Aged↗

PubMed2002

Three-dimensional distribution patterns of PRL, GH and ACTH cells in the house musk shrew ( Suncus murinus).

Despite a multitude of reports on the classification and distribution of anterior pituitary cells, no previous study has attempted to obtain the three-dimensional (3D) and computer-graphic distribution pattern of each cell type in the whole pituitary. Therefore, we mapped the anterior pituitary cells of the house musk shrew ( Suncus murinus) and found a distinct cellular distribution pattern. Serial horizontal sections of whole shrew pituitaries were stained immunohistochemically for prolactin (PRL), growth hormone (GH), and adrenocorticotropic hormone (ACTH) cells. The contours of positive cells and the anterior, intermediate, and posterior lobes in each section were digitized for 3D visualization by a volume rendering method. The reconstructed images and virtual frontal and sagittal slices were examined in detail. On the 3D reconstructed images, the PRL and GH cells had similar distribution patterns, although the former were concentrated in the dorsolateral and ventrocentral portions, and the latter in the dorsocentral portions of the anterior lobe. On both sides of the pituitary stalk, there lay portions that were conspicuous by scarcity of PRL and GH cells. ACTH cells were widely scattered throughout the whole anterior lobe, but they were very few in the above portions and the dorsocentral portions where GH cells were concentrated. No sex difference in the distribution patterns of each cell type was observed. However, PRL cells in females were more numerous than in males, whereas the opposite was true for GH and ACTH cells. We discuss the relationship between the formation of the spatial distribution patterns and anterior pituitary ontogeny.

Adrenocorticotropic Hormone↗

PubMed1997

Analysis of interactions between the codon-anticodon duplexes within the ribosome: their role in translation.

Computer graphics simulation of interactions between the codon-anticodon duplexes formed by normal elongator tRNAs at the ribosomal A, P and E-sites (the AP and PE interduplex interactions) was made. This demonstrated that only the correct duplexes at the A-site are compatible with the AP interduplex interaction. The selection of synonymous codons and anticodon wobble bases, together with the AP interduplex interaction, prevents frameshifting. In the absence of this interaction the efficiency of the selection falls off sharply. This suggests that the AP interduplex interaction should be retained during translocation and in the post-translocation state, i.e. the PE interduplex interaction that is identical with that of AP should exist to avoid frameshifting. In such a model the P-site duplex provides an indirect linkage between the A and E-site duplexes. The indirect linkage prohibits the simultaneous existence of the A and E-site duplexes. The wobble pairs of the P and E-site duplexes can affect the rate of the A-site occupation via the AP interduplex interaction and the AE interduplex indirect linkage. It is demonstrated that frameshifting can occur from the AP or PE codon-anticodon complex destabilization caused, for example, by small mobility of the wobble pairs, misreading of the codon, unmodified adenine and guanine at tRNA positions 34 (wobble) and 37, respectively. The results obtained can be subjected to direct experimental tests.

Anticodon↗

PubMed2004

Modeling the anatomical distribution of sunlights.

One of the major technical challenges in calculating solar irradiance on the human form has been the complexity of the surface geometry (i.e. the surface-normal vis-a-vis the incident radiation). Over 80% of skin cancers occur on the face, head, neck and back of the hands. The quantification, as well as the mapping of the anatomical distribution of solar radiation on the human form, is essential if we are to study the etiology of skin cancers or cataracts or immune system suppression. Using advances in computer graphics, including high-resolution three-dimensional mathematical representations of the human form, the calculation of irradiance has been attained to subcentimeter precision. Lighting detail included partitioning of direct beam and diffuse skylight, shadowing effects and gradations of model surface illumination depending on model surface geometry and incident light angle. With the incorporation of ray-tracing and irradiance algorithms, the results are not only realistic renderings but also accurate representations of the distribution of light on the subject model. The calculation of light illumination at various receptor points across the anatomy provides information about differential radiant exposure as a function of subject posture, orientation relative to the sun and sun elevation. The integration of a geodesic sun-tracking model into the lighting module enabled simulation of specific sun exposure scenarios, with instantaneous irradiance, as well as the cumulative radiant exposure, calculated for a given latitude, date, time of day and duration. Illustration of instantaneous irradiance or cumulative radiant exposure is achieved using a false-color rendering--mapping light intensity to color--creating irradiance or exposure isopleths. This approach may find application in the determination of the reduction in exposure that one achieves by wearing a hat, shirt or sunglasses. More fundamentally, such an analysis tool could provide improved estimates of scenario-specific dose (i.e. absorbed radiant exposure) needed to develop dose-response functions for sunlight-induced disease.

Adult↗

PubMed1992

Synthesis and use of 3-amino-4-phenyl-2-piperidones and 4-amino-2-benzazepin-3-ones as conformationally restricted phenylalanine isosteres in renin inhibitors.

The design of P2-P3 conformational restrictions in renin inhibitors by the use of a renin computer graphic model led to the synthesis of inhibitors containing N-Boc, N-acetyl, and N-phthalyl derivatives of 3(S)-amino-4(R,S)-2-piperidones and 4(S)-amino-2-benzazepinones in place of phenylalanine in the control compound N-acetyl-L-phenylalanyl-N-[4(S)-[(butylamino)carbonyl]-1(S)- (cyclohexylmethyl)-2(S)-hydroxy-5-methylhexyl]-L-norleuci namide (32). The piperidone inhibitors were prepared by utilization of the Evans chiral auxilliary to introduce the amino group with enantioselectivity and also to act as a leaving group in an intramolecular cyclization to the piperidone. The most potent inhibitor, 3(S)-(acetylamino)-alpha(S)-butyl-N-[4(S)- [(butylamino)carbonyl]-1(S)-(cyclohexylmethyl)-2(S)-hydroxy-5- methylhexyl]-2-oxo-4(R)-phenyl-1-piperidineacetamide (18, IC50 = 21 nM), was 25-fold less potent than the acyclic control 32. Considerable dependence of potency with the size of the P4 derivative was observed as had been expected based on the presynthetic modeling studies. Attempts to rationalize the observed potencies on the basis of further molecular modeling studies suggested that the loss in inhibitor potency was due to the conformational restrictions distorting the 3S center from the geometry present in the putative extended conformation present when the inhibitor is bound within the renin active site.

Benzazepines↗

PubMed1997

Landmark methods for forms without landmarks: morphometrics of group differences in outline shape.

Morphometrics, a new branch of statistics, combines tools from geometry, computer graphics and biometrics in techniques for the multivariate analysis of biological shape variation. Although medical image analysts typically prefer to represent scenes by way of curving outlines or surfaces, the most recent developments in this associated statistical methodology have emphasized the domain of landmark data: size and shape of configurations of discrete, named points in two or three dimensions. This paper introduces a combination of Procrustes analysis and thin-plate splines, the two most powerful tools of landmark-based morphometrics, for multivariate analysis of curving outlines in samples of biomedical images. The thin-plate spline is used to assign point-to-point correspondences, called semi-landmarks, between curves of similar but variable shape, while the standard algorithm for Procrustes shape averages and shape coordinates is altered to accord with the ways in which semi-landmarks formally differ from more traditional landmark loci. Subsequent multivariate statistics and visualization proceed mainly as in the landmark-based methods. The combination provides a range of complementary filters, from high pass to low pass, for effects on outline shape in grouped studies. The low-pass version is based on the spectrum of the spline, the high pass, on a familiar special case of Procrustes analysis. This hybrid method is demonstrated in a comparison of the shape of the corpus callosum from mid-sagittal sections of MRI of 25 human brains, 12 normal and 13 with schizophrenia.

Algorithms↗

PubMedDate not supplied

Effects of an eyeglass-free 3-D display on the human visual system.

PURPOSE: To investigate the effect on the human visual system of viewing 3-dimensional (3-D) computer graphics (CG) images with an eyeglass-free rear-cross-lenticular-type 3-D display. METHODS: Positive accommodation velocity (GRAD) during the accommodative step response was measured in ten healthy young adults before and after they viewed CG images. Although the distance between the viewer and the 3-D display was 600 mm, the apparent distance between the viewer and the virtual object was varied (515, 600, and 722 mm) by changing the visual disparity. RESULTS: A significant slowdown of average GRAD was observed by 60 min after a 30-min 3-D viewing of 3-D CG images [P<0.05, analysis of variance (ANOVA)] but not after a 30-min viewing of the CG images on a 2-D display or after a 15-min 3-D viewing. When the virtual object was at 722 mm, a significant slowdown of average GRAD was observed only at 30 min after the 30-min 3-D viewing (P<0.05, ANOVA). When the virtual object was at 515 mm, a significant slowdown of average GRAD was observed at 30 and 60 min after the 3-D viewing (P<0.05, ANOVA). CONCLUSIONS: The effect on the human visual system of 3-D viewing of 3-D CG images depends on both the duration of the viewing and the apparent distance between the viewer and the virtual objects.

Accommodation, Ocular↗

PubMed1990

Insights into the function of the zinc hydroxide-Thr199-Glu106 hydrogen bonding network in carbonic anhydrases.

The exact functional role of the zinc hydroxide (water)-Thr199-Glu106 hydrogen bond network in the carbonic anhydrases is unknown. However, from the results of molecular dynamics simulations (MD) we are able to better define its function. From computer graphics analysis and MD simulations on the zinc hydroxide form of human carbonic anhydrase II we find that this interaction forces the hydroxide hydrogen atom to be in a "down" position relative to the deep water-binding pocket. From previous work we have found that this pocket is a high-affinity binding site for CO2. We also note that during the timescale of our simulation (126 ps) the hydrogen bonds between the hydroxide hydrogen atom and Thr199 and the one between Thr199 and Glu106 are not fluxional. We propose that the role of the zinc hydroxide (water)-Thr199-Glu106 hydrogen bond network is to lock the hydrogen atom in the down position in order to expose the CO2 molecule bound in the deep water pocket to a lone pair of the hydroxide oxygen atom. This would allow for the rapid reaction of the CO2 molecule around the zinc ion. Furthermore, if the hydroxide hydrogen atom were not locked in the down position the binding of CO2 to the deep water pocket could be interfered with by the unrestrained hydroxide hydrogen atom (e.g. the N-Zn-O-H torsion could undergo rotational transitions that would partially block the deep water pocket). In summary, the roles we ascribe to this hydrogen bonding network are (1) to allow for facile access of CO2 to the deep water pocket and (2) to allow for maximal exposure of a hydroxide oxygen lone pair to the CO2 carbon atom.

Binding Sites↗

PubMed1986

Structure-function relationships of thrombin based on the computer-generated three-dimensional model of the B chain of bovine thrombin.

The advent of sophisticated computer graphics systems that permit the representation of macromolecular structure has made it possible to examine protein structure in detail. We have used one aspect of this technology to develop a model of thrombin. The model is based on structural and functional similarities this enzyme exhibits with respect to proteins found in the family of serine proteinases. This review has covered interpretations of the structure of the model based on analyses of data that had been collected before and after the model was developed. On one hand, the conceptualization of primary and secondary features in the model of the active site of thrombin has for the most part been preceded by data from experiments on the interaction of thrombin with naturally occurring substrates and inhibitors. The features of the model explain these data adequately. On the other hand, the model has been more recently used in an interactive way to derive information about the bioregulatory aspects of thrombin. The realization that the amino-terminus portion of the cyanogen-bromide fragment was probably not part of the chemotactic activity, because it was probably internalized in the native protein, has suggested that synthetic analogs should focus more on the carboxyterminus of the peptide. It is hoped that in the future the model will continue to serve more in this function and that it can be used to explore further other aspects about the structural and functional relationships of this enzyme.

Amino Acid Sequence↗

PubMed1999

Quantitative assessment of osseous, ocular, and periocular changes after hypertelorism surgery.

The purpose of this study was to develop a methodology to quantify osseous, ocular, and periocular fat changes caused by correction of orbital hypertelorism to test the hypothesis that there is a quantitatively predictable relationship between the movement of the osseous orbit and that of the ocular globe. A retrospective review was performed of 10 patients who were status post unilateral or bilateral transcranial medial orbital translocation, for whom there were archival digital data for preoperative and postoperative (mean interval = 30 months) three-dimensional computed tomographic (CT) scans. In addition to standard demographic and surgical data, the clinical preoperative and postoperative interpupillary and intermedial canthal distances were recorded. By using a computer graphics workstation, the CT digital data were registered to four surgically unaltered anatomic fiducial points to allow longitudinal quantitative comparisons. The following three-dimensional measurements were made for each patient preoperatively and postoperatively: interdacryon and interocular centroid distances, and on a standard series of three horizontal and two vertical planes, the position of the medial and lateral orbital walls, and the thickness of the medial and lateral periorbital fat (20 orbits). CT digital distances were compared with similar clinical distances when possible. The age at operation ranged from 4.0 to 12.5 years (mean, 6.6 years). The reduction in interdacryon distance exceeded the reduction in intercentroid distance (mean interdacryon change = -5.3 mm versus mean intercentroid change = -2.7 mm). Although there was a strong correlation between the amount of reduction of the lateral orbital wall and intercentroid distances, there was only a moderate correlation between the reduction in the intercentroid distance and that of the medial orbital wall. Similarly, there was a moderate correlation between the decrease in thickness of the lateral periorbital fat and the reduction of intercentroid distance but not of the medial orbital fat. In conclusion, medial translocation of the orbit does not produce equivalent movement of the ocular globe; neither the intermedial canthal nor the interdacryon distance is a useful predictor of ocular centroid position; and if the goal of hypertelorism operation is reduction of interocular distance, then CT measurement of globe intercentroid distance is essential for outcome assessment.

Adipose Tissue↗

PubMed1993

Three-dimensional structure of dog Sertoli cells: a computer-aided reconstruction from serial semi-thin sections.

The three-dimensional structure of the Sertoli cell in the Korean Jindo dog was investigated by scanning and transmission electron microscopy. Additionally, type-A and type-B Sertoli cells were simulated by three-dimensional computer graphic imaging to clarify the anatomical relationship between Sertoli cell and germ cells. Descriptions in the present study are based on examination of the reconstructed type-A cells at stages IV, V and VI of the spermiogenetic cycle and stages VII, VIII and IX of the reconstructed type-B Sertoli cells. Morphologically, three types of Sertoli cell processes were evident: 1) flat club-like, elliptical processes bifurcating and trifurcating randomly; 2) slender cord-like, tubular processes; and 3) sheet-like processes. The sheet-like processes rested upon more than half the surface of each round spermatid located in the proximity of the Sertoli cell. Curiously, just before spermiation, the apical club-like processes shifted from their initial position at the spermatid head and subsequently covered the disengaged residual body, after which the residual body was no longer evident in the tubule. Though the mechanism for this elimination is not known, the process suggests a reciprocity between the Sertoli and germ cells. An anatomical dissimilarity between type-A and type-B Sertoli cells appeared in the apical region, with the apical club-like processes of the type-B Sertoli cell given off by sheet-like processes as well as by the Sertoli column. At the base of all Sertoli cells, sophisticated sheet-like processes paralleled the basal lamina, tenaciously adhering end-to-end to the sheet-like processes of adjacent Sertoli cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1997

Examination of the ability of people to identify early changes of melanoma in computer-altered pigmented skin lesions.

OBJECTIVES: To examine whether older people were less able to distinguish changes of melanoma than younger people, and to test whether an educational brochure illustrating changes of melanoma would increase their ability to detect the changes. DESIGN: Photographic images of pigmented skin lesions were altered using computer graphics software. Images of typical changes of melanoma were shown to groups of volunteers younger than 30 years (n = 52) and older than 45 years (n = 41). Short intervals (seconds) between viewing of the original and changed lesions were used to test ability to distinguish the changes, and longer intervals (29 and 60 days) were used to test their ability over more realistic intervals. All participants were randomized to receive an educational brochure (designed using the same technology) to evaluate whether this would assist in identifying early changes of melanoma. SETTING: A cross section of volunteers employed in a large semigovernment utility. INTERVENTION: An educational brochure that illustrated typical changes of melanoma. MAIN OUTCOME MEASURE: Score of correct or incorrect detection of changed or unchanged skin lesions. RESULTS: Tests at short intervals showed that both age groups were able to detect early changes of melanoma but had poor ability to detect changes of melanoma at longer intervals. Repeated viewing of the original lesions enabled the participants to once more recognize the changes. Both groups had low ability to detect the appearance of new pigmented lesions. The educational brochure improved the ability of participants to detect change. CONCLUSIONS: The main difficulty people have in self-detection of melanoma is limited ability to recall the appearance of their skin. This ability did not differ between the age groups. Educational material that focused on change was effective in increasing the ability to detect changes over short intervals. Photographic records may be the most effective aid for detection of changes at longer intervals.

Adult↗