Biomedical subjects

F Hoffmann

Publications and source records attributed to F Hoffmann.

At least 55 records · Page 3Linked to original sources

PubMed1996

The influence of penetrating keratoplasty and cyclosporin A therapy on MHC class II (Ia)-positive cells in the rat iris and choroid.

BACKGROUND: The presence of Ia-positive cells (MHC class II equivalent) has been previously reported in the iris and choroid of various species. They have been reported to have both round and dendritic morphologies; the latter may represent classic dendritic cells, potent antigen-presenting cells (APCs). It is possible that the dendritic-like cells play a important role in (auto)immune processes of uveal and other ocular tissues. Using the flat or whole mount technique, the distribution of Ia-positive cells in the rat iris and choroid was investigated following penetrating keratoplasty (PKP) and following treatment with cyclosporin A (CsA). METHODS: Lewis (LW) rats received corneal buttons from Lewis-Brown Norway (LW-BN) donors and were randomly assigned to the following groups: (i) operated, untreated (n = 24); (ii) operated, CsA-treated (10 mg/kg i.m.; n = 22). Controls were groups (iii) normal LW rats (n = 13); (iv) unoperated, CsA-treated (16 days' treatment; n = 8); (v) anterior perforation of the anterior chamber (n = 3); (vi) eight corneal sutures only (n = 4); (vii) syngeneic operated (LW to LW; n = 4). Animals of groups (i) and (ii) were killed on the 5th, 9th and 13th postoperative days and on appearance of the corneal rejection (group i, day 13; group ii, day 16). Both eyes were enucleated, immediately fixed, and iris-choroid flat mounts were examined for Ia-positive cells using APAAP immunohistochemistry. RESULTS: In the normal Lewis rat iris, scattered Ia-positive cells of both nondendritic and dendritic morphology were observed. CsA treatment in the unoperated rat did not result in a significant decrease in the percentage of dendritic cells in the iris or choroid. Anterior chamber perforation, the placement of sutures in the cornea and syngeneic PKP resulted in a moderate increase in iris Ia-positive cells. Allogeneic transplantation resulted in a large increase in both types of Ia-positive cells, particularly on day 13 with corneal rejection. In group ii, an initial decrease in Ia-positive cells until day 13 was observed; upon rejection (day 16), the histological picture was similar to that of untreated animals. Alterations in the operated choroid were also apparent following CsA treatment. CONCLUSION: Corneal transplantation in the Lewis rat results in an increase in Ia-positive cells in the iris; CsA therapy can delay but not prevent this reaction. Changes in choroidal Ia-positive cells following PKP were not apparent, their numbers being affected only by CsA treatment following grafting.

Animals↗

PubMed1996

The behaviour of ED1- and ED2-positive cells in the rat iris and choroid following penetrating keratoplasty and cyclosporin A therapy.

BACKGROUND: The presence, morphology and distribution of ED1 and ED2+ cells have been recently reported in detail in the uveal tissues of the rat. These cells, particularly those of dendritic morphology, are possibly capable of antigen presentation and, therefore, may play an important role in immune processes of uveal and other ocular tissues. Using the whole-mount technique, the distribution of ED1+ and ED2- cells in the rat iris and choroid was investigated following penetrating keratoplasty (PKP) and following treatment with cyclosporin A (CsA). METHODS: Lewis (LW) rats received corneal buttons from Lewis-Brown Norway (LW-BN) donors and were randomly assigned to one of two groups: (I) operated, untreated (n = 24); (II) operated, CsA treated (10 mg/kg i.m.: n = 22). Four groups served as controls: normal LW rats (n = 13); (IV) unoperated, CsA treated (16 days' treatment; n = 8); (V) eight corneal sutures only, representing a simulated or "sham" operation (n = 4); (VI) syngeneic operated (LW to LW: n = 4). Animals of groups I and II were killed on the 5th, 9th and 13th postoperative days and on appearance of the corneal rejection (group I, day 13; Group II, day 16). Both eyes were enucleated, immediately fixed, and iris-choroid flat mounts were examined for ED1+ and ED2+ cells using APAAP immunohistochemistry. RESULTS: In the normal LW rat iris, ED1+ and ED2+ cells of both non-dendritic and dendritic morphology were observed. The placement of sutures in the cornea and PKP with or without treatment resulted in a reasonably regular response in both the iris and the choroid in the operated and partner eye. These included: (a) an increase in round iridal ED1+ and ED2+ cells in the operated eye and in round ED1+ cells in the partner eye; (b) a decrease in dendritiform ED2+ cells in the iris of the operated eyes as well as in the partner eye; and (c) a decrease in the dendritiform ED2+ cells in the choroid of the operated and partner eye. CsA treatment alone in unoperated animals resulted in significant decreases in the number of dendritiform ED1+ cells in the iris and in the dendritiform ED2+ cells in the choroid. CONCLUSION: Corneal transplantation in the Lewis rat results in responses in ED1+ and ED2+ cells in uveal tissues in both the operated eye as well as in the partner eye. The differences in cell behaviour supports the idea that distinct immune-competent cell populations are present within uveal tissues and that they may have differing roles in the pathological eye.

Animals↗

PubMed1996

In vitro inhibition of human cytomegalovirus replication by calcium trinatrium diethylenetriaminepentaacetic acid.

Desferrioxamine (DFO) has been shown to inhibit human cytomegalovirus (CMV) replication in vitro. In the present study, we compared antiviral effects of DFO in human foreskin fibroblast (HFF) cells against several CMV strains with those of other chelators that interact with iron and other ions from different pools. DFO, a hydrophilic chelator, that may chelate both intracellular and extracellular ions inhibited production of CMV late antigen at 50% effective concentrations (EC50S) ranging from 6.2 to 8.9 microM. EC50S for calcium trinatrium diethylenetriaminepentaacetic acid (CaDTPA) ranged from 6.1 to 9.9 microM. EC50S for 2,2'-bipyridine (BPD), a hydrophobic chelator, which diffuses into cell membranes ranged from 65 to 72 microM. Concentrations which inhibited BrdU incorporation into cellular DNA by 50% (IC50S) ranged from 8.2 to 12.0 microM (DFO), from 65 to 89 microM (BPD), and from 139 to 249 microM (CaDTPA). CaDTPA was the only chelator which completely inhibited production of infectious virus in HFF and vascular endothelial cells at concentrations which had no significant effects on cellular DNA synthesis and growth. Addition of stoichiometric amounts of Fe3+ in the culture medium of HFF cells completely eliminated antiviral effects of DFO while antiviral effects of CaDTPA and BPD were only moderately affected. Fe2+ and Cu2+ were stronger inhibitors of CaDTPA than Fe3+; however, Mn2+ and Zn2+ completely suppressed antiviral effects of CaDTPA. The results show that CaDTPA is a novel nontoxic inhibitor of CMV replication. The antiviral activity of CaDTPA is suppressed by metal ions with a decreasing potency order of Mn2+/Zn2+ > Fe2+ > Cu2+ > Fe3+.

2,2'-Dipyridyl↗

PubMed1996

Flow-cytometric analysis of peripheral lymphocytes in the rat following penetrating keratoplasty and immunosuppressive treatment.

Flow cytometry has been found to be a useful tool in the clinical monitoring of patients following solid organ transplantation. Despite the easier assessibility of corneal graft acceptance or rejection, flow-cytometric evaluation of peripheral lymphocytes following systemic immunosuppression is important in the evaluation of therapeutic efficacy. The systemic effect of penetrating keratoplasty (PKP) and of immunosuppression with cyclosporin A (CsA), leflunomide (LF), and the nondepleting anti-CD4 antibody, RIB 5/2, on peripheral lymphocytes was investigated in the rat model. Corneal buttons were grafted from Lewis/Brown Norway rats to Lewis recipients. Animals were randomly assigned to the following treatment groups: (1) untreated; (2) CsA, 10 mg/kg; (3) LF, 10 mg/kg; (4) LF, 5 mg/kg; (5) LF, 2.5 mg/kg; (6) LF, 10 mg/kg; combined with CsA, 10 mg/kg; and (7) RIB 5/2, 4 mg/kg, combined with CsA, 1.5 mg/kg. Controls included the following groups: (8) unoperated, CsA-treated at 10 mg/kg; (9) unoperated, LF-treated at 10 mg/kg; (10) unoperated, LF-treated at 10 mg/kg and CsA-treated at 10 mg/kg; (11) unoperated, RIB 5/2-treated at 4 mg/kg and CsA-treated at 1.5 mg/kg; (12) syngeneic grafts; and (13) normal Lewis rats. Cells from blood and spleen samples were enriched using Ficoll density centrifugation, and lymphocytic surface markers CD 3, CD 4, CD 8, and RT 1b (Ia) were analyzed by direct immunofluorescence using flow cytometry. In the untreated allogeneic PKP, a decrease in the percentage of serum CD 3+, CD 4+, CD 8+, and CD 4+ RT 1b+ lymphocytes was apparent from the 5th to the 9th postoperative day. At corneal graft rejection, a normalization of serum CD 3+ and CD 4+ levels occurred, whereas the percentage of serum CD 8+ lymphocytes remained slightly raised. Significantly enhanced decreases in levels of CD 4+ lymphocytes were observed following treatment with CsA, LF, and, particularly, therapy with RIB 5/2 and a subtherapeutic dose of CsA. Concomitant decreases were also apparent following treatment with CsA or LF. In contrast, the combination of RIB 5/2 and CsA (1.5 mg/kg) resulted in a reactive increase in levels of CD 8+ lymphocytes as well as an increased expression of RT 1b by the remaining CD 4+ lymphocytes. The latter alterations corresponded to indefinite acceptance of the corneal grafts, which was observed only in the animals treated with RIB 5/2 and CsA. PKP in the rat model is accompanied by alterations in peripheral lymphocytes. Additional influences are exerted by immunosuppressive therapy, with the most specific and predictable alterations being achieved with anti-CD4 monoclonal antibody therapy.

Animals↗

PubMed1996

Keratokyphosis in rabbits: a functional and morphologic study.

Keratokyphosis, a "nonfreeze keratomileusis" procedure, was applied in rabbits. The refractive changes were -6.5 +/- 0.7 (SD), -9.5 +/- 2.6, and -13.0 +/- 3.2 D for convex applanation surfaces with a vertex of +100 microns, +125 microns, and +150 microns in the microkeratome and +1.5 +/- 2.0 and +2.5 +/- 2.6 D for concave applanation surfaces with a vertex of -100 microns and -125 microns. The pachymetric corneal changes were +43 +/- 24 microns, +39 +/- 32 microns, and +71 +/- 24 microns for the convex applanation surfaces and -21 +/- 40 microns and -17 +/- 24 microns for the concave. Wound healing was uncomplicated. The scar at the interface was 0-5 microns wide. The mean central density of nerve endings was 1,255 +/- 532/mm2. The endothelial cell size was 25.1% (p < 0.01) greater as measured by specular microscopy than by vital preparation technique; this difference was greater with higher (33.4%) than with lower (18.02%) corneal refraction (p = 0.02). In addition, there was a method-independent correlation (correlation coefficient, -0.63) between endothelial cell count and corneal thickness. This may indicate an increased demand on corneal endothelium in thickened corneas.

Animals↗

PubMed1995

Arthroscopic shoulder stabilization using Mitek anchors.

The purpose of this paper is to report our experience with an arthroscopic stabilization technique using bone anchors in the treatment of chronic unidirectional anterior-inferior shoulder instability. 30 of 32 patients (average age, 26 years) were followed for an average of 24 months (range 12 to 36). There were 28 patients with dislocations and four with subluxations. In the group of the dislocators five patients had more than 10 dislocations and 15 patients between one and seven (average three). In 68% a sport injury was the reason for the first dislocation. Due to the length of the labroligamentous detachment two to four anchors were used for stabilization. According to the criteria of Rowe, in the group of the subluxators (4) two had an excellent and two a good result. In the group of the dislocators (26) two patients dislocated their shoulder again after reconstruction without a new accident, one had a recurrent dislocation from significant trauma. Two of them had an open stabilization afterwards. Overall there were 53.9% excellent, 34.6% good and 11.5% poor results. In 50% there was no restriction of shoulder motion, 21% had a loss of external rotation of 5 degrees and 29% of 10 degrees. Arthroscopic shoulder stabilization with help of Mitek anchors seems to be a good method for treatment of chronic unidirectional anterior-inferior instabilities with less than 10 dislocations preoperatively. All patients, who suffered a spontaneous recurrent dislocation, had more than 10 dislocations before. In these cases this arthroscopic procedure is not suited to restore stability, even if a Bankart-lesion is present.

Adolescent↗

PubMed1995

Accuracy of corneal lenticules produced for lamellar refractive corneal surgery.

The layer thickness of the corneal lenticules separated with the Berlin microkeratome and shaped by keratomileusis, keratophakia, keratokyphosis, and intrastromal excimer-laserkeratomileusis was measured with the Universal Measuring Microscope. The vertices of most corneal lenticules showed an undercorrection of the measured values compared with the calculated ones. In keratomileusis, the vertex of the central part of the optical zone of 3.6 mm attained 79 +/- 19 microns instead of 80 microns (99%); in keratophakia, 74 +/- 19 microns instead of 80 microns (93%); in myopic keratokyphosis, 77 +/- 11 microns instead of 105 microns (74%); in hyperopic keratokyphosis, 72 +/- 28 microns instead of 105 microns (69%); and in excimer-laserkeratomileusis, 52 +/- 12 microns instead of 39 microns (120%). The undercorrection of myopic and hyperopic keratokyphosis indicate that this type of nonfreeze keratomileusis is not capable to cut a tissue lens of predicted refraction from compressed corneal tissue. Near symmetrical profiles were achieved in all types of refractive corneal surgery but excimer-laserkeratomileusis had the smallest standard deviation. It was significantly smaller than in hyperopic keratokyphosis (p < 0.05). Intrastromal excimer-laserkeratomileusis of tightly fixed corneal lenticule in the Berlin microkeratome might be the most predictable method of lamellar refractive corneal surgery.

Animals↗

PubMed1995

Indications, results, and complications of refractive corneal surgery with mechanical methods.

Radial keratotomy (RK) incisions permanently weaken the cornea. This structural weakening can cause several complications and side effects, including diurnal fluctuation, progressive hyperopic shift, and the potential for traumatic rupture of the keratotomy scars. Minimally invasive-RK may be a useful alternative to reduce the invasiveness of RK while retaining its efficacy. Mild myopia can be treated by either RK or photorefractive keratectomy. Patients treated by RK in the first eye and photorefractive keratectomy in the second eye preferred the speed of recovery and the clarity of vision with RK. Combining the microkeratome and the excimer laser appears to be an ideal technique to correct high myopia. Laser ablation of the corneal lenticule while securely fixed by the suction ring in the Berlin microkeratome offers the advantage of perfect centration and fixation. Hexagonal keratotomy, used to treat hyperopia, appears to be an unpredictable, unsafe surgical procedure.

Cornea↗

PubMed1995

Disturbances in renal microcirculation induced by myoglobin and hemorrhagic hypotension in anesthetized rat.

The question was studied of whether myoglobin (Mb), when released into the general circulation during hemorrhagic hypotension (HH), causes disturbances of renal blood flow. In anesthetized rats 250 mg/kg Mb was intravenously infused within 1 h; HH at 50 mmHg with subsequent retransfusion was induced for 30 min. By allowing two dyes to circulate for 1 and 3 min, respectively, and detecting their localization histologically after rapid freezing of the organ, intrarenal distribution of capillary blood flow was studied. In contrast to the results obtained with Mb or HH alone, when Mb was infused during HH, the development of large areas within cortex and medulla lacking any capillary perfusion was observed. In > 70% of the tissue, a distance > 60 microns to the next dye-labeled capillary was found (in controls 0%). At this time total renal flow had decreased from 5.3 to 0.20 ml/min (HH without Mb: 5.1 to 1.1 ml/min). It is concluded that the observed changes in renal blood flow contribute to the known direct nephrotoxic potential of Mb.

Animals↗

PubMed1995

Delay in corneal allograft rejection due to anti-CD4 antibody given alone and in combination with cyclosporin A and leflunomide.

Anti-CD4 monoclonal antibodies (mAbs) have been shown to inhibit in vitro T-cell activation and proliferation to both antigens and mitogens. Animals studies have demonstrated the immunosuppressive potency of anti-CD4 mAbs given in vivo for therapy of autoimmune disease and following allografting. Similarly, leflunomide (LF), a new potent immunosuppressive, has been shown to be effective in preventing autoimmune disorders and reactions leading to organ transplant rejection. LF is thought to antagonize cytokine activity, thereby interfering with T-helper-cell-dependent B- and T-lymphocyte proliferation. A new anti-CD4 antibody (RIB 5/2) was investigated alone and in combination with cyclosporin A (CsA) and LF for the treatment of corneal allograft rejection in the rat. Corneal buttons were grafted from Lewis/Brown Norway rats to Lewis recipients. Animals were randomly assigned to the following treatment groups: (1) untreated; (2) CsA at 1.5 mg/kg; (3) RIB 5/2 at 2.5 mg/kg; (4) RIB 5/2 at 2.5 mg/kg and CsA at 1.5 mg/kg; (5) RIB 5/2 at 2.5 mg/kg, CsA at 1.5 mg/kg and LF at 10 mg/kg; (6) RIB 5/2 at 4 mg/kg; (7) RIB 5/2 at 4 mg/kg and CsA at 1.5 mg/kg; and (8) RIB 5/2 at 4 mg/kg, CsA at 1.5 mg/kg, and LF at 10 mg/kg. RIB 5/2 was given intraperitoneally at 24 h before surgery, on the day of grafting, and on postoperative day 1 and was continued every 2nd day until the rat had received ten doses in all (postoperative day 15).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1994

Hydrolase participation in allograft rejection in rat penetrating keratoplasty.

BACKGROUND: A rat model of orthotopic corneal graft rejection was used to investigate the alterations in hydrolase activity within the corneal graft or within cellular infiltrates during acute rejection. METHODS: The distribution of the lysosomal enzymes [acid phosphatase (AP), N-acetyl-beta-D-glucosaminidase (NAG), beta-glucuronidase (beta-Gluc), beta-galactosidase (beta-Gal), dipeptidylpeptidase II (DPPII)] and of the membrane-bound proteases [aminopeptidase M (APM), aminopeptidase A (APA), gamma-glutamyltransferase (GGT), alkaline phosphatase (ALP), dipeptidylpeptidase IV (DP-PIV)] were investigated by histochemical methods in the grafts at 3, 5, 8, 10 and 12 days following allogeneic transplantation. Serial sections of the grafts were also examined for RT1b, CD4, CD4+, CD8, CD11b/c and CD45, in order to determine hydrolase activity within infiltrating cells. RESULTS: Allogeneic grafts were invaded by macrophages, CD4- and CD8-positive lymphocytes. In contrast, syngeneic grafts, performed as a control, contained occasional lymphocytes and focal aggregations of macrophages around suture sites. The allogeneic cellular infiltrate stained intensely for AP and ALP; moderately for beta-Gluc, NAG and beta-Gal; and mildly for GGT, DPPII and APM in grafts at all postoperative times. Serial sectioning indicated that the majority of the lysosomal hydrolases were located in macrophages; AP, APM and GGT were, however, observed in lymphocytes. Vessel ingrowth could be observed with enzyme staining for AP, beta-Gluc, NAG, ALP, APA and APM. Hydrolase activity in the corneal endothelium served as an indicator of endothelial function during the rejection process. CONCLUSION: Changes in normal hydrolase activities in corneal grafts in the rat model indicate decreasing corneal function during the rejection process. Hydrolases released from infiltrating cells contribute to the morphological disruption and, possibly, to graft rejection.

Animals↗

PubMed1994

Leflunomide therapy following penetrating keratoplasty in the rat.

BACKGROUND: The isoxal derivative, leflunomide (LF), is a new potent immunosuppressive which has been shown to be effective in preventing autoimmune disorders and reactions leading to organ transplantation rejection. LF is thought to antagonise cytokine activity and thereby to interfere with T-helper-cell-dependent B- and T-lymphocyte proliferation. METHODS: We used LF to treat corneal allograft rejection in the rat, comparing its effect with that of cyclosporin A (CSA). Corneal buttons were grafted from Lewis/Brown Norway rats to Lewis recipients. Animals were randomly assigned to the following treatment groups: I, untreated; II, CSA (10 mg/kg i.m.); III, LF (2.5 mg/kg p.o.); IV, LF (5 mg/kg p.o.); V, LF (10 mg/kg p.o.); VI, combined therapy (LF 10 mg/kg p.o. and CSA 10 mg/kg i.m). Treatment began on the first postoperative day and was continued until rejection occurred. RESULTS: The mean graft rejection time in the untreated allogeneic group was 12 days. A significant delay in graft rejection was observed in all treatment groups compared with group I (P < 0.001). Further, the delay in graft rejection resulting from combined therapy (group VI) was statistically significant compared with all other groups (P < 0.001). CONCLUSION: These results suggest that (a) LF when used alone is as effective as CSA in treating corneal allograft rejection in the rat, and (b) when LF and CSA are combined they are more effective than either drug alone in the prolongation of allograft survival.

Administration, Oral↗

PubMed1994

[Ginkgo extract EGb 761 (tenobin)/HAES versus naftidrofuryl (Dusodril)/HAES. A randomized study of therapy of sudden deafness].

80 patients with idiopathic sudden hearing loss existing no longer than 10 days were included in a randomised reference-controlled study. The therapeutic value of Ginkgo EGb 761 (Tebonin) + HAES was compared to that of Naftidrofuryl (Dusodril)+HAES. The main mechanisms of action of EGb 761 are a vasoregulating activity (increased blood flow), the platelet activating factor antagonism and a prevention of membrane damage caused by free radicals. Naftidrofuryl has antiserotonergic and therefore vasodilatory properties. The statistical analysis of the audiometric data was performed in measuring the relative hearing gain as described by Eibach 1979. After one week of observation, 40% of the patients in each group showed a complete remission of hearing loss. This was also observed by other authors who had compared other drugs. Therefore, in these cases, it is most likely that spontaneous recovery is the most important factor. After two and three weeks of observation, measuring the relative hearing gain, there was a significant borderline benefit of EGb 761 (p = 0.06) without any side effects. Some patients of the reference group developed side effects such as orthostatic dysregulation or headache or sleep disturbances. Minimising side effects should be one of the most important goals in therapy of sudden hearing loss until the efficiency of infusion therapy is proved.

Adult↗

PubMed1994

Interleukin-2 receptor--targeted therapy by monoclonal antibodies in the rat corneal graft.

A possible selective therapeutic approach to corneal graft rejection will aim at IL-2 receptor-bearing antigen-activated T-lymphocytes with monoclonal anti IL-2R antibodies. In a rat penetrating keratoplasty model (Lewis x Lewis-BN) comparing to controls (median, 8 days), a significant delay of the allograft reaction was achieved by applying a therapeutic dose (15 mg/kg bw) of cyclosporin A (median, 18 days; p < 0.01), an intraperitoneal (1.0 mg/kg bw) (median, 13.5 days; p < 0.05) or a subconjunctival injection of IL-2R mab (0.5 mg/kg bw ART-18) (median, 16 days; p < 0.01) with low-dose Cyclosporin A (1.5 mg/kg bw). In pharmacokinetic experiments, the corneal radioactivity 24 h after intraperitoneal injection of 125I-labeled ART-18 was < 1% (p < 0.01) of the values obtained by subconjunctival injection, whereas the serum radioactivity values (p > 0.05) were in the same range. The above results suggest that the onset of an allograft reaction in perforating keratoplasty seems to depend on the locally achievable antibody concentration and can be delayed with a high level of IL-2 R mab present in the immediate surrounding of the foreign antigen-expressing cells.

Animals↗

PubMed1994

Immunohistochemistry study of the glaucomatous and normal human trabecular meshwork.

Although class II-expressing cells have been reported previously in the human trabecular meshwork (HTM), the exact identity of these cells and their possible role in the normal and the pathological state remains unclear. Preliminary results suggest increased human leucocyte antigen (HLA)-DR expression in the glaucomatous TM. To investigate this possibility, 20 trabeculectomy specimens obtained from patients with primary open-angle glaucoma (POAG) were examined immunohistochemically for HLA-DR, leucocyte common antigen (LCA; CD45) and a macrophage marker (CD68). The patients varied in age from 42 to 86 years (average, 69 years). The degree of antibody staining in the TM was compared with that of 20 human control eyes obtained from an eye bank less than 24 h after death. The donors varied in age from 47 to 91 years (average, 69 years); there was no known history of eye disease amongst the control group. Evaluation of specimen was performed by two observers using a grading system ranging from negative (0) to strongly positive (3) and by computer-aided optic densitometry. HLA-DR-positive cells were present in both the normal and the glaucomatous TM. Occasional cells stained for LCA and CD68 in the TM of both groups. Subpopulations of the HLA-DR-staining cells were apparent on serial sectioning. An age effect on antigen staining was not observed; postmortem delay of greater than 48 h resulted in decreased specimen antigenicity. Both evaluation techniques failed to reveal a significant difference in HLA-DR, LCA or CD68 staining between the glaucomatous and the normal TM.

Adult↗

PubMed1994

HLA-B and -DR match reduces the allograft reaction after keratoplasty.

Since 1983, corneal grafts have been routinely obtained from multiorgan donors and allocated to the patient with the greatest HLA compatibility. At follow-ups in 248 primarily clear corneal grafts, grouping according to the HLA mismatch rate revealed that the incidence of allograft reactions did not differ significantly for HLA-A but certainly did for HLA-B (P < 0.01) and, in patients with a poor prognosis, for HLA-DR as well (P < 0.05). Grouping the patients according to the mismatch rate of the total of four HLA-B and -DR antigens disclosed the incidence of allograft reactions to be markedly increased by a mismatch of more than two antigens (P < 0.05). The relative risk of an allograft reaction is increased by factors of 5.1 in patients with a good prognosis and 5.5 in those with a poor prognosis. The adverse influence of a postoperative inflammation on the occurrence of an allograft reaction as seen in nonmatched donor material is no longer present in matched donor material if the prognosis is good and no longer significant if it is poor (P < 0.09). The inflammation-promoted expression of HLA antigens is of less importance for graft survival if the difference in the HLA antigens is reduced by the match.

Cornea↗

PubMed1993

[Spontaneous dislocation of a silicone disk lens 4 months postoperative into the vitreous body].

We report on a patient who experienced an acute deterioration in visual acuity at night four months after implantation of a silicon-disc lens into the capsular bag. On examination, the artificial lens was localized preretinally. The capsular equator was fibrous, but had retained its circular shape. The posterior capsule was ruptured. The rupture may be explained by tension in the posterior capsule, which is only 1-4 microns thick, within the shrunken capsular bag, and by an acute increase of intraocular pressure caused by rubbing of the eyes during sleep.

Aged↗

PubMed1993

Mechanical methods in refractive corneal surgery.

Keratorefractive surgery has developed rapidly over the past decade. For patients with aphakia, however, posterior chamber lenses are safer and more predictable than refractive corneal surgery; myopia is the greatest challenge to this type of surgery. No technique as yet has an accuracy that is adequate for the general treatment of myopia. Keratotomy is the most common procedure currently performed for the correction of mild myopia and astigmatism. Results are less accurate and less stable with myopic than with aphakic epikeratoplasty. Although it is technically more difficult, keratomileusis seems to be more predictable than epikeratophakia. Nonfreeze lamellar corneal surgery accelerates wound healing. Synthetic lenses and ring-shaped implants are also being developed to modify corneal refraction. Current research is directed toward laser stromal keratomileusis on discs that are removed from the cornea using a microkeratome.

Corneal Stroma↗