Search PubMed⌕ Search

Biomedical subjects

M R Allansmith

Publications and source records attributed to M R Allansmith.

At least 73 records · Page 4Linked to original sources
PubMed1985

Identification of proteins in contact lens surface deposits by immunofluorescence microscopy.

Worn soft contact lenses from five asymptomatic subjects were examined by immunofluorescence microscopy for type of protein on the lens surface. Lysozyme was the predominant protein component identified by this technique. IgA was also identified in deposits on all five lenses, but the staining was less intense than that for lysozyme. Lactoferrin was identified on the surface of four lenses, one of which stained intensely for this protein and three less intensely. IgG was identified on two contact lenses; the staining was less intense than that for lysozyme. New, never-worn soft contact lenses did not stain for any of the proteins examined in this study. We conclude that several normal tear proteins are capable of contributing to surface deposits on soft contact lenses, and all worn soft contact lenses have protein adherent to their surface as a result of normal wear.

Adult↗
PubMed1985

The ocular secretory immune system of the rat.

Ocular tissues and tears of adult male rats were examined for the presence of immunoglobulins (Ig) and secretory component (SC). By immunofluorescent analysis, we found the highest density of Ig-containing cells in the exorbital (lacrimal) gland. In contrast, few if any Ig-containing cells were observed in the conjunctiva or Harder's gland. IgA was the most frequent cell-associated isotype identified in the exorbital gland, and the number of IgA-containing cells was much greater than that of IgM- or IgG-containing cells. With respect to IgG, cell counts were fairly evenly distributed among the various subclasses. No IgE-containing cells were detected in ocular tissues. SC was identified exclusively within the acinar cells of the exorbital gland. In tears, IgA was the predominant isotype and occurred almost entirely in the polymeric form. Of the IgG subclasses, IgG 2a was present in the greatest concentration. Only trace amounts of IgG 2b were found, and IgG 1, IgG 2c and IgM could not be detected. The level of free SC in tears was relatively high, compared to the concentration of free SC reported in other mucosal secretions. These results suggest that the exorbital gland is the primary tissue associated with the ocular secretory immune system of the rat. Furthermore, our findings indicate that rat tears contain components that may provide immune defense for the ocular surface.

Animals↗
PubMed1985

Anaphylaxis of ocular adnexa induced by infection of anti-IgE antibody.

To examine the role in ocular tissue injury of anaphylaxis alone (as distinct from other mechanisms possibly present in a model involving immunization), a model of anaphylaxis was produced by injection of rabbit anti-rat IgE antibody into ocular adnexal tissues of rats. Adnexal swelling, seen within 15 min, disappeared by 6 hr. Vascular permeability and weight of adnexal tissues were increased at 0.5 hr and had returned to near normal levels by 6 hr. Histologic study revealed extensive degranulation of mast cells at 0.5 hr after injection and a return to normal by 24 hr. Neutrophils reached a level of 7400/mm3 at 6 hr and returned to normal by 24 hr. Macrophages accumulated by 24 hr in all tissues, including control eyes injected with normal serum. The similarity of results from this 'pure' model of anaphylaxis to results from a model produced by injecting antigen into ocular adnexal tissues of immunized rats suggests that anaphylactic mechanisms are responsible for the changes seen in the antigen-injected model.

Anaphylaxis↗
PubMed1985

Effect of anaphylaxis on conjunctival goblet cells.

Rats undergoing ocular anaphylaxis induced by systemic or local injection of antigen, topical application of antigen, or topical application of compound 48/80 were evaluated conjunctival goblet cell changes that might be related to anaphylaxis. The number of goblet cells in 1 micron, alkaline Giemsa-stained sections averaged 500/mm2 of epithelium in normal rats; this number was not significantly changed in any of the experimental groups. Goblet cells in control rats occasionally demonstrated evacuation of their contents (less than 1%) or upward displacement of the intracellular bolus of mucus (about 1%); these percentages were not increased in anaphylaxis. Topical application of 2.0 micrograms of histamine induced an intracellular displacement of mucus in both control animals and animals undergoing anaphylaxis. These findings suggest that in ocular anaphylaxis the amount of histamine released may be insufficient to produce such intracellular changes. Our results indicate that in ocular anaphylaxis in the rat, there is no light microscopic evidence of increased mucus discharge from conjunctival goblet cells. Increased mucus in secretions of patients with ocular allergic syndromes may not be attributable to anaphylactic mechanisms alone.

Administration, Topical↗
PubMed1985

Molecular forms of tear IgA and distribution of IgA subclasses in human lacrimal glands.

Tears and sera from 14 subjects were analyzed for IgA levels by radioimmunoassay by use of secretory IgA standards for tear samples and monomeric IgA standards for serum samples. [corrected] Tears from subjects without conjunctival inflammation contained 93% polymeric IgA (pIgA) and 7% monomeric IgA; tears from subjects with conjunctival inflammation had less pIgA (79%). Biopsy specimens of 11 lacrimal glands and one accessory lacrimal gland were obtained from 12 additional subjects. Tissues were stained with polyclonal antisera for immunoglobulins, J chain, and secretory component. In addition, tissues were stained for IgA subclasses with monoclonal reagents specific for IgA1 and IgA2. IgA plasma cells predominated over other types of plasma cells, and most were J chain positive. Secretory component, although absent from the interstitium of the gland, was found in most acinar and ductal cells. The average proportion of IgA1 to IgA2 cells was 56% to 44%. We concluded that the lacrimal system of the human resembles other exocrine systems in the production of predominantly pIgA and the nearly equal occurrence of IgA1 and IgA2 plasma cells.

Adolescent↗
PubMed1985

Histochemical analysis of secretory vesicles in nongoblet conjunctival epithelial cells.

An Alcian-blue/Periodic acid Schiff reagent (AB/PAS) pH dependent staining method was used to identify the mucus content of secretory vesicles of non-goblet epithelial cells of the human conjunctiva. Twenty subjects were selected for biopsy of the midcentral upper tarsal conjunctiva: 10 subjects had no contact lens wearing experience, and 10 subjects wore contact lenses. Human respiratory epithelium was used as a control for the staining procedure. Four-micron paraffin sections of conjunctival and control tissues were stained with Alcian blue at pH 2.5 and 1.0 and counterstained with PAS. Non-goblet epithelial cell secretory vesicles contained neutral mucin, sialmucin, and sulphomucin. This study provides evidence for a 'second' mucus system of the conjunctiva, that this system is in the non-goblet epithelial cells, and that the mucus of this system has sulphomucins, sialomucins and neutral mucins.

Conjunctiva↗
PubMed1985

Hormonal influence on the secretory immune system of the eye: androgen modulation of IgA levels in tears of rats.

The objective of the present studies was to determine whether hormones influence the level of IgA in tears of rats. Our results demonstrated that IgA concentrations in tears of male rats were significantly higher than those of females. This difference appeared to be due to an effect of androgens. Castration of male rats led to a significant decline in the content of tear IgA. Administration of testosterone offset this response and stimulated a time-dependent accumulation of IgA in tears of orchiectomized rats. This hormone action was only elicited by androgens, and not by other classes of steroid hormones. The testosterone-induced increase in tear IgA levels may have involved enhanced local production of IgA, and was found to occur in parallel with an elevation in tear secretory component concentrations. These findings indicate that androgens may regulate the ocular secretory immune system of the rat.

Animals↗
PubMed1985

Gender-related differences in the morphology of the lacrimal gland.

Previous research has demonstrated that distinct, gender-related differences exist in the morphology of the rat lacrimal gland. The purpose of the present study was to determine whether this sexual dimorphism is unique to the rat, or extends as well to other species. Lacrimal glands were collected from adult male and female rats, mice, guinea pigs, rabbits and humans (biopsies). Tissues were processed for light microscopy and examined with a Zeiss Videoplan II image analysis system. For morphometric determinations, we measured the area of approximately 50 glandular acini per animal for a total count of greater than 244 acini per gender per species. Our results demonstrated that significant gender-related differences exist in lacrimal glands of rats, mice, guinea pigs, rabbits, and humans. In all species analyzed, acinar area in lacrimal glands of males was larger than that of females. These findings suggest that gender differences in lacrimal gland morphology may be a general phenomenon in a variety of species.

Animals↗
PubMed1984

Surface deposits on worn hard contact lenses.

Giant papillary conjunctivitis (GPC) is associated with deposits on contact lenses. We used scanning electron microscopy to study the anterior surface of 30 hard contact lenses, both cleaned and not cleaned, worn by patients with GPC and with keratoconus and by asymptomatic subjects. Uncleaned lenses worn by asymptomatic subjects for one day had deposits on about 5% of the surface. In most cases, the deposits were removed completely by one cleaning. Uncleaned lenses worn by patients with GPC or keratoconus had deposits on about 90% of the surface. Most of these deposits were removed by one cleaning. However, residual deposits after cleaning were greater on lenses from patients with keratoconus than on those from patients with GPC. Lenses from asymptomatic subjects rarely had residual deposits after cleaning. We found that the types of deposits on worn soft and hard contact lenses are similar, that there are fewer deposits on hard lenses than on soft lenses, and that deposits on hard lenses, unlike those on soft lenses, generally can be removed by one cleaning.

Conjunctivitis↗
PubMed1984

Mononuclear and IgA-containing cells in the lacrimal gland of germ-free and conventional rats.

Mononuclear cells in the lacrimal (exorbital) glands of five germ-free, five ex-germ-free, and five age-matched conventional rats were counted by light microscopy. Tissues from these rats were also examined by electron microscopy. IgA-containing plasma cells were counted by immunofluorescence microscopy in the lacrimal glands of five germ-free and five conventional rats. The median number (and range) of mononuclear cells per ten high-power fields was 25 (14-28) in germ-free rats, 33 (32-43) in ex-germ-free rats, and 41 (36-50) in conventional rats. The median number (and range) of IgA-containing plasma cells per ten high-power fields was two (0-5) in germ-free and 44 (29-72) in conventional rats. The differences in the numbers of mononuclear cells in the lacrimal glands of germ-free as compared with ex-germ-free and with conventional rats were statistically significant (P less than 0.004). The difference between the numbers of IgA-containing plasma cells in germ-free as compared with conventional rats was also statistically significant (P less than 0.004). Electron microscopy revealed that the mononuclear cells in all groups of rats consisted of macrophages and lymphocytes. These observations suggest that the number of mononuclear cells, and particularly IgA-containing plasma cells, in the rat lacrimal gland can be increased by systemic and/or local immunologic stimulation.

Animals↗
PubMed1984

Late-phase reactions in ocular anaphylaxis in the rat.

We assessed whether anaphylactic stimulation of rat ocular tissue produces a late-phase reaction at the histologic level. Clinical changes of swelling and redness started within minutes, peaked at about 20 min, and then subsided. Neutrophils increased at 1/2 hr after stimulation, peaked at 6 hr, and subsided to normal at 24 hr. Eosinophils reached a significant increase at 6 hr. Compaction of vessel contents was present at 1/2 hr; vessels were normal thereafter. Extravasated red blood cells and debris in the tissue were prominent at 6 hr. Macrophages had accumulated significantly at 6 hr and maintained that level at 24 hr. Any effect of anaphylaxis on macrophage accumulation was masked because control-injected ocular tissue also showed an accumulation of macrophages at 24 hr. Our results demonstrate that in ocular tissue, as in skin, the early acute phase of immediate hypersensitivity is but one stage of a multiphasic reaction.

Anaphylaxis↗
PubMed1984

Source of IgA in tears of rats.

The purpose of the present study was to determine whether IgA in rat tears originates from serum and/or local synthesis. To examine the first possibility, we compared the IgA levels in serum and tears of rats with a portacaval anastomosis. This operation induced a chronic and progressive elevation of polymeric IgA concentrations in serum. By 8 weeks after surgery, serum IgA levels in 'portacaval' rats were 20-fold higher than those of sham-operated or intact controls. In contrast, IgA levels in tears of 'portacaval' rats did not increase after surgery, despite the availability of free secretory component (SC) in tears. The lack of correlation between tear and serum IgA concentrations resulted in a significant decrease in the tear IgA/serum IgA ratio after anastomosis surgery. To assess whether tear IgA might be derived from local synthesis, we cultured various ocular tissues from male rats in the presence or absence of cycloheximide, an inhibitor of protein synthesis. Incubation of exorbital (lacrimal) glands resulted in the accumulation of substantial quantities of IgA in the culture medium. This accumulation was significantly reduced by the presence of cycloheximide. In contrast, cycloheximide had no effect on the amounts of IgA in cultures of 'lids', Harder's glands and globes. These results indicate that IgA in rat tears originates from local synthesis and not from serum transfer. Furthermore, our findings suggest that the rat exorbital gland is responsible for the synthesis and secretion of tear IgA.

Animals↗
PubMed1984

Hormonal influence on the secretory immune system of the eye: androgen regulation of secretory component levels in rat tears.

The present study examined the influence of gender and steroid hormones on the level of free secretory component (SC) in tears of rats. The SC concentration in tears of male rats was approximately five-fold greater than that found in tears of females. This difference could not be accounted for by variations in tear volume or a suppression of tear SC content in female rats during certain stages of the estrous cycle. Rather, the elevated level of SC in tears of males appeared to be due to the effect of androgens. Castration of male, but not female, rats resulted in a time-dependent decrease in the SC content of tears. Administration of testosterone to orchiectomized rats reversed this decline and induced a time- and dose-dependent increase in the tear SC concentration. This response appeared specific for androgens, because treatment of orchiectomized rats with progesterone, estradiol, or cortisol had no effect on total tear SC. Consistent with this hypothesis was our finding that injection of castrated male rats with 5 alpha-dihydrotestosterone also raised the tear SC concentration. Of interest, the androgen-induced increase of the SC level in tears was not accompanied by similar changes in total tear protein. These results suggest that androgens may influence the production and/or secretion of SC by ocular tissues. Furthermore, our findings indicate that androgens play a role in the ocular secretory immune system of the rat.

Androgens↗
PubMed1984

Hormonal influence on the secretory immune system of the eye: androgen control of secretory component production by the rat exorbital gland.

Androgens are known to regulate the level of secretory component (SC) in tears of male rats. The purpose of the present study was to explore the underlying mechanism of this hormone action by (i) identifying the ocular tissue(s) involved in SC production; and (ii) determining whether androgens increase SC production by this tissue. We also examined whether androgen administration influenced the concentration of SC in tears of female rats. Ocular tissues from adult Sprague-Dawley rats were cultured in the presence or absence of cycloheximide in the incubation medium. Secretory component in the culture media was measured by an RIA which detects primarily free SC. Analysis of media obtained after incubation of exorbital (lacrimal) glands, 'lid' tissues, globes, and Harderian glands revealed that only exorbital glands released substantial amounts of SC. This exorbital gland production of SC, which was significantly greater in tissues from male rats, as compared to those of female rats, was reduced by approximately 50% when cycloheximide was present in the culture medium. To determine whether SC production by exorbital glands was influenced by androgens, orchiectomized glands was influenced by androgens, orchiectomized rats were administered either saline or testosterone (2.0 mg/day for 4 days), and exorbital glands were cultured 24 hr after the last injection. Testosterone treatment in vivo induced a significant, cycloheximide-sensitive increase in SC production in vitro, compared to the glandular SC output of saline-injected controls. It is interesting that similar androgen treatment of ovariectomized females also resulted in elevated tear SC concentrations and enhanced output of SC by their exorbital glands in vitro. These findings indicate that the exorbital gland is primarily responsible for SC production in the rat eye and that androgens may modulate the synthesis of SC in this gland.

Animals↗
PubMed1983

Treatment of contact lenses with papain. Increase in wearing time in keratoconic patients with papillary conjunctivitis.

In 15 Keratoconic patients with papillary conjunctivitis associated with wearing rigid polymethylmethacrylate contact lenses, the cleaning of the lenses with enzymatic contact lens cleaner (papain) increased lens wearing time in nine and diminished the symptoms of mucus and itching in 12. In 13 control, lens-wearing keratoconic subjects with papillary conjunctivitis, three had a decrease, four had an increase, and six had no change in lens wearing time and one had a diminution of symptoms. Use of the enzymatic contact lens cleaner did not, however, influence the biomicroscopic appearance of the papillary conjunctivitis. The inclusion of the enzymatic contact lens cleaner in the cleaning regimen offered an adequate improvement in wearing time and tolerance for three of four patients that previously suffered a reduction in wearing time that compromised or precluded their vocational responsibilities.

Adult↗
PubMed1983

Ultrastructure of mast cells in rat ocular tissue undergoing anaphylaxis.

In a study of ocular tissues undergoing anaphylaxis, in uninjected rats most mast cells contained electron-dense granules with no discernible internal structure. A few cells showed varying degrees of swelling of the matrix granules. In rats injected with normal rabbit serum, more mast cells showed swelling of the granule matrix and a few showed extensive swelling of nearly all granules. Mast cells from rats undergoing anaphylaxis by either anti-IgE or antigen injection showed membrane and granule alterations: extensive dendritic processes, fusion of granule membranes, fusion between granule and plasma membranes, and disruption of plasma membranes. Communication was established between the exterior of the cell and contents of individual granules of cisternae formed by several fused granules. The matrix of nearly all granules was extensively swollen.

Anaphylaxis↗
PubMed1983

Macrophages in ocular tissues of rats. Determination of their number after local anaphylaxis and other procedures.

The number of macrophages in rat ocular tissues was determined, with the tip of the eyelid containing about 3,000 macrophages per cubic millimeter, which is similar to the number of mast cells at this site. Fewer macrophages were present in orbital tissues and conjunctiva. Macrophages accumulated in ocular tissues of immunized rats injected locally with antigen, but the number did not exceed that observed in antigen-injected controls. Injection of various fluids into ocular tissues, but not the trauma of needle punctures alone, stimulated a marked accumulation of macrophages. Thus, the response to nonspecific stimuli masked the macrophage response to antigen-induced, ocular anaphylaxis.

Anaphylaxis↗