Development and validation of an exercise performance support system for people with lower extremity impairment.

OBJECTIVE: To identify innovative strategies to support appropriate, self-directed exercise that increase physical activity levels of people with arthritis. This article reports on one interactive, multimedia exercise performance support system (PSS) for people with lower extremity impairments in strength or flexibility. METHODS: An interdisciplinary team developed the PSS using self-report of lower extremity musculoskeletal impairments (flexibility and strength) to produce an individualized exercise program with video and print educational materials. Initial evaluation has investigated the validity and reliability of program assessments and recommendations. RESULTS: PSS self-report and professional assessments were similar, with more impairments indicated by self-report. PSS exercise recommendations were similar to those made by 3 expert physical therapists using the same exercise data base. Results of PSS impairment assessments were stable over a 1-week period. CONCLUSION: PSS exercise recommendations appear to be reliable and a valid reflection of current exercise knowledge in rheumatology. Furthermore, users were able to complete the computer-based program with minimal assistance and reported it to be enjoyable and informative.

AI/Learn/Rheumatology. A computer-assisted educational system for teaching about rheumatic diseases.

Education of health professionals about the rheumatic diseases is in need of improvement. The computer is an instrument that can be used efficiently to educate large numbers of users. With specific educational principles in mind, we developed AI/Learn/Rheumatology, a computer-assisted interactive videodisc system for teaching the rheumatic diseases. While interacting with the user, it conveys knowledge using visual and problem-solving techniques. The system is efficient, enjoyable to use, and useful for small groups and independent study. It is applicable for teaching medical and allied health professional students, postgraduate trainees, and primary care physicians.

Effectiveness of computer-assisted interactive videodisc instruction in teaching rheumatology to physical and occupational therapy students.

A computer-assisted interactive videodisc instructional program, HP-RHEUM was designed to teach clinical findings in arthritis to occupational and physical therapy students. Using the Rheumatology Image Library videodisc produced by the National Library of Medicine, HP-RHEUM consists of instructional modules which employ advance organizers, examples/nonexamples, summaries, and immediate feedback. To see if HP-RHEUM would be as effective as traditional classroom instruction, control data were collected in 1991 from 52 OT and PT students. Treatment data were collected from 61 students in 1992 when HP-RHEUM entirely replaced lectures. Identical pre- and post-tests consisted of 70 multiple choice questions, with 24 matched to slides. On the slide questions the HP-RHEUM group had significantly higher scores. Otherwise, there was no significant difference in performance between groups. HP-RHEUM provided an independent learning method and enhanced visual comprehension of rheumatologic disease concepts.

Scanning electron microscopic observations on the eruption of primary teeth in the opossum.

Just prior to the emergence of the tooth into the oral cavity, a small circular crater forms in the gingival epithelium immediately above the crown. The craters appear to expand in diameter during eruption to accommodate the emerging crown of the tooth. The observations support the concept that the crown of the tooth does not actively push through and rupture the gingival epithelium, but rather that the epithelium degenerates and then the tip of the crown emerges into the formed defect.

Postnatal development of the spleen in Didelphis virginiana.

The postnatal development of the spleen has been examined in 85 opossums ranging in age from newborn to adult. At birth the spleen consists of a well vascularized mass of mesenchymal tissue and lacks lymphatic tissue or any evidence of haemopoietic activity. Haemopoiesis is evident at seven days, increases to a maximum at about two to three weeks and thereafter gradually declines. Although production of granulocytes has disappeared by 60 days postnatum, a small degree of erythropoiesis and megakaryocyte formation continues throughout life. Lymphatic tissue appears by the third week, but germinal centres do not appear until after weaning. A feature of the spleen during the first three to four days is the presence of a population of primitive 'blast' cells.

Leukocytes in the peripheral blood of the developing opossum.

Changes in the blood leukocytes have been studied in 112 opossums ranging in age from newborn to adult. Very few circulating leukocytes are present at birth, and these consist mainly of neutrophil granulocytes, with many immature forms. Leukocytes increase rapidly in number during the first 2 weeks of postnatal life, due to an accumulation of granulocytes. While all three types of granulocyte share in this early increase, initially it is the neutrophils which predominate. However, eosinophil granulocytes increase rapidly and their number soon equals or exceeds that of the neutrophils. Eosinophils remain a prominent, but lesser, component of the blood leukocytes throughout all subsequent periods of development. Lymphocytes are present only in small numbers during the first 8--10 days of postnatal life, and during this time small lymphocytes are absent from the peripheral blood. Apart from increased lobation of the granular leukocytes, the white blood cells show no remarkable cytological changes during the postnatal period.

Transitory cell attachments in the differentiating glomerular epithelium of the opossum metanephros.

Numerous transitory intercellular attachments are observed between the central, lateral surfaces of adjacent glomerular epithelial cells in the differentiating renal corpuscle. The junctions are characterized by an increased electron density of the adjacent cell membranes and cytoplasm. The intervening intercellular space may contain an amorphous material of moderate electron density. The distribution and position of such temporary cell attachments, together with their modification and subsequent loss during the differentiation of podocytes, suggest that they play an important role in the histogenesis of the glomerular epithelium.

Pairing of spermatozoa in the epididymis of the opossum (Didelphis virginiana): a scanning electron microscopic study.

Spermatozoa of the opossum, Didelphis virginiana, were taken from three different regions of the epididymis and examined by scanning electron microscopy, phase-contrast and dark-field microscopy. It has been demonstrated that marked morphological changes occur in spermatozoa during their passage through the epididymis. In the first segment or head of the epididymis, spermatozoa are non-motile and the long axis of their nuclei is perpendicular to that of the tail. The nucleus is V-shaped with a thick and a thin arm. At the junction of the two arms. At the junction of the two arms, where the arms join, the articular fossa receives the capitulum of the connecting piece which attaches the head of the spermatozoon to the tail. Spermatozoa from the central region of the epididymis show a re-orientation of the nuclei which now lie parallel to the long axis of the tail. Both paired and unpaired spermatozoa are found and show an increase in motility. In the caudal region of the epididymis all spermatozoa are paired. Pairing occurs as a result of the close apposition of adjacent cell membranes covering the acrosomes of the larger arms.

Scanning electron microscopic observations on developing opossum embryos: days 9 through 12.

During the first 9 d of development in Didelphis, the 3 germ layers are established and the initial formation of their derivatives occurs. During this time the embryos float within uterine secretions, each separated from the uterine mucosa by a shell membrane. Organogenesis begins during the last 3 1/2 d of the 12 1/2 d gestation period and corresponds to the time when the yolk sac placenta is associated with the uterine epithelium. During this period development proceeds at an explosive rate, culminating in a fetus-like creature capable of surviving in the pouch. Early in d 10, the forelimbs are present as limb buds. Late in the 10th d the embryo descends into and becomes enveloped by its own yolk sac. Mandibular and hyoid arches, and prominent digital ridges on the forefeet are characteristic external features. By d 11, the hindlimb is represented by a bud the eyes and external auditory meatus are established and an open mouth with protruding tongue is characteristic of this stage. Digits are present on the forefeet but lack claws. During the 12th d the oral shield develops, curved claws are prominent features of the forefeet and digital ridges are seen on the hindfeet. Prior to birth the periderm covers the eyes, ear pinnae and sides of the mouth.

Scanning electron microscopic observations on the opossum yolk sac chorion immediately prior to uterine attachment.

The 10 day opossum embryo is enclosed by a yolk sac chorion in which distinct vascular and non-vascular regions are established before attachment to the uterine epithelium. The embryo is closely associated with the vascular region which becomes adherent to the uterine lining. Cells of the external layer bear abundant, closely packed, long microvilli, which may serve to absorb nutrients from the uterine secretions. Cells of the inner surface show only scattered microvilli and microplicae on their apical surfaces.

Morphological observations on the parathyroid of the opossum (Didelphis virginiana).

Parathyroid III of the opossum, Didelphis virginiana, lies on the medial surface of the internal carotid artery at its origin just above the bifurcation of the common carotid artery. It is limited externally by a capsule and is subdivided into lobule-like structures by connective tissue septae. The parenchyma consists solely of chief (principal) cells, arranged in irregular cords and clumps supported by a delicate vascular connective tissue. Ultrastructurally, the chief cells are polyhedral in shape and have centrally placed nuclei. The cytoplasm contains small, randomly distributed, rod-shaped mitochondria, scattered profiles of granular endoplasmic reticulum, free ribosomes, and small perinuclear Golgi complexes. Secretory granules are small, electron-dense, and appear to be limited by a delicate membrane. The granules are related both to the Golgi complex and the basal cell membrane. Capillaries that lie immediately adjacent to the chief cells show an extensively fenestrated endothelium.

Ultrastructural observations on the shell membrane of the North American opossum (Didelphis virginiana).

Each developing opossum embryo is surrounded by a shell membrane which completely separates embryonic and maternal tissues. During the eighth and ninth prenatal days, the embryos together with their limiting shell membranes float freely within the uterine lumen, surrounded only by the secretions of the uterus. The shell membrane is transparent, nonelastic, tough, and capable of extreme deformation. It consists of a mat of interwoven fibers which vary in external diameter, are electron dense, and show no apparent substructure. The morphology and arrangement of component fibers are similar throughout the width of the shell membrane.

Structure of the paws in Didelphis virginiana.

The paws of Didelphis virginiana show several unusual features. They possess dermatoglyphs on the foot pads, have opposable first digits and the pads show a peculiar vascular arrangement. The hallux lacks a claw. The degree of innervation and the number and size of Pacinian corpuscles indicates that the paws of the opossum are finely sensitive to pressure and vibration.