Biomedical subjects

L S Fujikawa

Publications and source records attributed to L S Fujikawa.

26 records · Page 2Linked to original sources

PubMed1984

Basement membrane components in healing rabbit corneal epithelial wounds: immunofluorescence and ultrastructural studies.

The nature of the substrate that supports epithelial migration in vivo is of interest, particularly with respect to mechanisms of wound healing. Immunofluorescence and electron microscopy were used to search for common substrate components in prototype rabbit corneal wounds: epithelial scrape wounds, in which the corneal or conjunctival epithelium migrated over the denuded lamina densa of the corneal basement membrane (CBM), and superficial keratectomy, in which the corneal epithelium migrated over a bare stroma without CBM. The corneal epithelium moved rapidly over the CBM or stroma to cover the defect within 2-3 d, whereas the conjunctival epithelium required 1-2 wk. In all wounds, fibronectin and fibrin/fibrinogen were deposited onto the bare surface within 8 h after wounding and persisted under the migrating epithelium until migration was complete. Bullous pemphigoid antigen (BPA), a normal component of the CBM, was removed with the epithelium upon scrape wounding and reappeared in the CBM after migration was completed. In contrast, the conjunctival epithelium had a continuous subepithelial band of BPA out to the migrating tip. Laminin, also a normal component of the CBM, was not removed in the scrape wounds, indicating that the region of least resistance to shear stress was between the BPA and laminin layers. Laminin was removed by superficial keratectomy and was not detectable under the leading edge of the migrating cells. Laminin and BPA were restored in the CBM by 2-4 wk. Type IV collagen could not be detected in normal CBM, but was conspicuously present in conjunctival basement membrane and in blood vessels. Focal bands of type IV collagen did appear in the newly synthesized CBM 2-4 wk after keratectomy. These results argue that BPA, laminin, and type IV collagen are not essential for the migration of corneal epithelium during wound healing and support the hypothesis that fibronectin and fibrin/fibrinogen are the common, perhaps the essential, components of the provisional matrix that serves as a substrate until the permanent attachment components are regenerated.

Animals↗

PubMed1984

Fibronectin in developing rabbit cornea.

Fibronectin is believed to be important in tissue morphogenesis. We examined the distribution of fibronectin in developing rabbit cornea by immunohistofluorescence. Cryostat sections of cornea from 13, 15, and 20-day-old fetuses, 3-day neonates, and adults were incubated with affinity-purified fluoresceinated guinea pig anti-rabbit fibronectin antiserum (aFN). aFN bound to components within the presumptive stromal region and along the basal surfaces of corneal and lens epithelia during early stages of mesenchymal invasion. At 15 days of gestation, fluorescence was associated with the stromal extracellular matrix of the cornea, the subepithelial zone, and the lens capsule. In the 20-day fetus an intense aFN fluorescence was present along the inner corneal stromal border coincident with the formation of Descemet's membrane. Fluorescence within the corneal stroma appeared as fine lines, restricted to the collagen lamellae, remaining through birth and disappearing in the adult. Although stromal fluorescence disappeared in the adult, Descemet's membrane continued to fluoresce, albeit to a lesser extent. The results of our studies indicate the presence of fibronectin in developing rabbit cornea. Because fibronectin is important to cell adhesion in vitro, and because intercellular and cell-extracellular matrix interactions, including adhesion, are necessary for tissue morphogenesis, our observation suggests that fibronectin plays an important role in corneal morphogenesis.

Animals↗

PubMed1983

Hyperosmolar hyperglycemic nonketotic coma. A complication of short-term systemic corticosteroid use.

Hyperosmolar hyperglycemic nonketotic coma is a serious and often lethal clinical biochemical syndrome. We report three cases of ophthalmic problems that were treated with a short course of oral corticosteroids and which resulted in the development of hyperosmolar hyperglycemic nonketotic coma. Two of these cases concerned relatively young, previously healthy patients and had fatal outcomes. The third patient, who was elderly, survived because of early detection and initiation of therapy. All three cases demonstrate that hyperosmolar hyperglycemic nonketotic coma is a serious potential complication of systemic steroidal therapy, even in a short course of treatment such as is often used in ophthalmology.

Administration, Oral↗

PubMed1982

T-cell subsets and Langerhans cells in normal and diseased conjunctiva.

To identify the infiltrating mononuclear cells in conjunctival lesions, we stained frozen tissue sections of conjunctiva with a series of monoclonal antibodies against T cells and T-cell subsets with an immunoperoxidase method. In vernal conjunctivitis and ocular pemphigoid, most lymphocytes reacted with the anti-T4 antibodies that define helper/inducer T cells (T4+); a minority reacted with the anti-T8 antibody that defines suppressor/cytotoxic T cells (T8+). However, T8+ cells predominated in a conjunctival specimen from a patient with chronic graft-vs-host disease. A few T8+ cells and rare T4+ cells were also found in normal conjunctiva. In some diseased conjunctivas, there was an increase in cells stained with anti-T6 antibody, which stains Langerhans cells in normal conjunctiva and skin. T lymphocyte subsets and Langerhans cells probably play an important role in the pathogenesis of inflammatory conjunctival lesions.

Antibodies, Monoclonal↗

PubMed1981

Fibronectin in healing rabbit corneal wounds.

Fibronectin, a glycoprotein present in plasma and extracellular matrix, is believed to be involved in cell-cell and cell-matrix interactions. Using immunofluorescence techniques, we studied the time course of appearance and distribution of fibronectin in healing rabbit corneal epithelial wounds and compared fibronectin to other selected proteins in the cornea. In the normal cornea, fibronectin was detected only in Descemet's membrane and not in the epithelial basement membrane. Shortly after wounding, fibronectin deposited on the denuded corneal surface and was a continuous prominent layer by 8 hours. The epithelium had begun to migrate over the deposited fibronectin by 22 hours and by 52 hours had completely covered the denuded surface. Fibrinogen/fibrin was also detected on the initial bare wound surface. Once the wound was reepithelialized, the subepithelial fibronectin and fibrin layer then progressively disappeared, so that by 2 weeks only a small amount was detected. Fibronectin also appeared in the deep stroma of corneas after wounding in elongated patches, a pattern suggestive of keratocyte association. Fibronectin had an inverse relationship to bullous pemphigoid antigen which was used as a marker for the lamina lucida of the epithelial basement membrane. The bullous pemphigoid antigen, which was found in the normal corneal epithelial basement membrane, was removed with the epithelium and reappeared during the wound healing when fibronectin was diminishing. IgG and albumin did not localize on the wound surface, and the diffuse staining seen in the stroma did not change during healing. These findings are compatible with the hypothesis that fibronectin and fibrin play a role in epithelial migration and temporary adhesion to the surface during corneal wound healing, at a time when the normal anchoring mechanism is lost.

Albumins↗

PubMed1980

Wound healing in cultured corneal endothelial cells.

Following the application of needle, intraocular lens, freeze, and laser wounds to the center of discrete 1 cm2 areas, density-limited monolayers of cultured rabbit corneal endothelium demonstrate wound healing responses similar to those seen in in vivo corneas. The wounded monolayer reforms in a time period consistent with that seen in both in vivo and in vitro organ culture models, thus suggesting that cell motility characteristics are not dependent upon an underlying Descemet's membrane. Density-limited, cultured monolayers of corneal endothelial cells present a good model for studying the response of the endothelium to a variety of stimuli.

Animals↗

PubMed1979

Family care in a family practice group.

A fundamental claim of family medicine is that the family physician treats the "whole" family--an ideological principle that guides undergraduate and residency education. Using archival data obtained from a random sample of 500 patients in one group of family physicians, this study analyzed the extent to which this principle is carried out in practice. Physicians trained in family practice residency programs were compared with their colleagues. Family types and marital stability were also examined. Results indicate that in only 28 percent of families (excluding single person households) were all family members seen by the same family physician. This occurred despite the high preponderance and stability of traditional nuclear families in the practice. There was no significant difference in this rate between graduates and nongraduates of approved family practice residency programs.

Adolescent↗

PubMed1975

Sera and the in vitro induction of immune responses. II. Inhibitory effects of newborn calf sera on primary humoral responses.

The effect of newborn calf (NBC) sera on the in vitro generation of immune responses were studied. NBC sera inhibited the generation of primary humoral responses to SRBC. The inhibitory activity was dose-dependent and diluted out rapidly. Adding inhibitory doses of NBC serum to test cultures at zero or 24 hr resulted in approximately the same amount of inhibition. Pulsing experiments showed that the test cultures were most sensitive to the inhibitory effects of NBC serum during the 24- to 48-hr period. In contrast to its inhibitory effects on primary humoral responses, NBC sera supported the in vitro generation of secondary humoral responses and significantly increased the responses of some of these over control levels. We found that sera obtained from newborn calves before nursing were not inhibitory for primary responses but sera obtained from the same calves 7 days later did inhibit these responses. We postulate that the inhibitory effects of NBC sera may represent a physiologic control mechanism which becomes active when immunologic maturity develops and that it possibly involves the inactivation of cell mediators.

Animals↗