Biomedical subjects

F Hoffmann

Publications and source records attributed to F Hoffmann.

At least 55 records · Page 3Linked to original sources

PubMed1998

Prolongation of corneal allograft survival by an interleukin-2-immunoglobulin fusion protein in mice.

BACKGROUND: Interleukin 2 (IL2) production by activated T-helper cells leads to activation and proliferation of cytotoxic T cells. Recently, an IL2-IgG fusion protein was found to suppress cell-mediated and humoral immune responses in mice. METHODS: We used the genetically engineered murine IL2-IgG2b fusion protein in a fully MHC-mismatched mouse keratoplasty model. The DTH reaction against sheep red blood cells was investigated as a measure of IL2-IgG2b-mediated immunosuppression. The animals were divided into three control groups (n > or = 6) [no treatment, subconjunctival (SQ) treatment with saline or mouse serum], two IL2 SQ-treated groups (14 micrograms or 140 micrograms), and four IL2-IgG2b-treated groups (14 micrograms, 140 micrograms or 280 micrograms SQ or 280 micrograms i.p.). RESULTS: Administration of 20 micrograms of IL2-IgG2b twice daily from the time of immunization until the time of challenge resulted in almost complete prevention of footpad swelling. The 140 micrograms SQ application of IL2 (allograft reaction on day 20.5 +/- 4.04) and the 280 micrograms SQ (day 19.2 +/- 2.48) or i.p. (day 19.7 +/- 1.5) application of IL2-IgG2b fusion protein significantly prolonged the corneal graft survival in comparison to the untreated group (day 13.4 +/- 1.35) (P < 0.01) or saline control group (P < 0.01) and the mouse-serum-treated group (day 14.7 +/- 3.5) (P < 0.05). CONCLUSION: Our results indicate that, at a total dose of 280 micrograms, the fusion protein IL2-IgG2b causes no detectable side effects and very effectively suppresses the immune response of the corneal allograft in mice. This fusion protein could prove useful in the treatment of allograft rejections and autoimmune diseases.

Animals↗

PubMed1998

Comparison of two antiretroviral triple combinations including the protease inhibitor indinavir in children infected with human immunodeficiency virus.

OBJECTIVE: The effects of two antiretroviral triple combinations including the protease inhibitor indinavir on the surrogate markers, viral load and CD4 cells were evaluated. METHODS: Fifteen patients with high viral load or disease progression under their prior antiretroviral therapy were switched to zidovudine/lamivudine/indinavir (Group A, n = 10) or stavudine/lamivudine/indinavir (Group B, n = 5). Serial determinations of viral load and CD4 cells were performed. RESULTS: The median reduction of the viral load was 0.6 log after 3 months and 0.8 log after 6 months in Group A and 2.5 and 2.4 log after 3 and 6 months in Group B, respectively. After 3 and 6 months 3 of 10 patients in Group A and 3 of 5 patients in Group B had viral load reductions below the detection limit of the assay. Patients with an additional switch of nucleoside analogues at start of indinavir therapy (regardless of the specific reverse transcriptase inhibitor used) had significantly better reductions of the viral load than patients without such a switch (median 2.3 log vs. 0.2 log after 6 months, P < 0.05). In Group A the median of the relative increase of CD4 cells was 37% after 3 months and 57% after 6 months (P = 0.002); in Group B the medians of the relative increase of CD4 cells were 145 and 163% (not significant), respectively. Two patients from Group A and 1 from Group B developed renal calculi, which resolved after adequate hydration. One patient was withdrawn because of intractable vomiting attributed to indinavir. CONCLUSION: In a small cohort of HIV-infected pediatric patients with extensive prior antiretroviral treatment, triple therapy including indinavir had a sustained effect on the decrease of the viral load and the increase of CD4 cells similar to results obtained in antiretrovirally experienced adults. This effect was significantly better in patients with an additional switch of a nucleoside analogue at start of triple therapy with indinavir than in patients without such a change.

Adolescent↗

PubMed1998

[The semitendinosus tendon as replacement for the anterior cruciate ligament].

This article describes the history, advantages, biomechanical properties, operative technique, and results of replacement of the anterior cruciate ligament using the semitendinosus tendon. After arthroscopic ACL replacement using the doubled semitendinosus tendon in combination with an extraarticular lateral repair in 65 consecutive patients (20 acute, 45 chronic instabilities) we found after 2 years in 51 patients (78%) an excellent or good result with less than 3 mm difference in the Lachman test measured with the KT-1000 arthrometer (MMD). After 6 years 40 out of the 45 patients with chronic instabilities could be examined again. Only 28 patients (70%) showed a difference in anterior translation of less than 3 mm. A positive pivot shift sign could be seen in 11% of the patients after 2 years and in 20% after 6 years. The Tegner score increased from 6.0 after 2 years to 6.2 after 6 years, the Lysholm score decreased from 93 to 91 in the same interval. 89% of the patients had a free range of knee motion after 2 years and 92.5% after 6 years. There were 10% normal, 50% nearly normal, 25% abnormal, and 15% severely abnormal knees in the IKDC evaluation after 6 years. In the last 4 years we are using the quadrupled semitendinosus tendon in an arthroscopic single incision technique for ACL replacement with femoral Endobutton fixation, because the doubled semitendinosus tendon seems to elongate over time. After 23 months on average (12-36 months) the preoperative anterior translation of 7.5 mm could be decreased to 1.9 mm in 35 patients.

Anterior Cruciate Ligament↗

PubMed1997

Preparation, characterization and cytotoxicity of methylmethacrylate copolymer nanoparticles with a permanent positive surface charge.

Methylmethacrylate copolymer nanoparticles containing different cationic comonomers such as N-trimethylammoniumethylmethacrylate (TMAEMC), N-dimethylammoniumethylmethacrylate (DMAEMC), N-trimethylammoniumpropylmethylacrylamide (MAPTAC) or the anionic comonomer sulfopropylmethacrylate (SPM), respectively, were prepared by free radical polymerization. Particle size was determined by photon correlation spectroscopy (PCS), transmission and scanning electron microscopy (TEM, SEM), and surface charge by microelectrophoresis. Pure poly(methylmethacrylate) nanoparticles served as control. Depending on the method, mean diameters of permanently positively-charged nanoparticles MMA-TMAEMC and MMA-MAPTAC were 243 or 207 nm (PCS), 161 or 201 nm (TEM), and 158 or 197 nm (SEM), respectively. Zeta potential examined in demineralized water or NaCl solution was +63.4 or +32.1 mV for MMA-TMAEMC nanoparticles and +49.2 or +32.0 mV for MMA-MAPTAC nanoparticles, respectively. Cytotoxicity of nanoparticles was determined by MTT assay in three different cell cultures including human foreskin fibroblasts (HFF) and two monkey kidney cell lines MA-104 and Vero. Cell viability profiles of TMAEMC and MAPTAC containing nanoparticles were different, showing IC(50) values for MMA-TMAEMC nanoparticles of 189.6+/-11.4 µg/ml (MA-104), 110.9+/-3.1 µg/ml (Vero) and 27.2+/-4.0 µg/ml (HFF). Cell viability at maximum concentration of 500 µg/ml MMA-MAPTAC nanoparticles was 98.3% (Vero), 85.7% (MA-104), or 94.0% (HFF), respectively.

Journal Article↗

PubMed1997

Ultrastructural changes in the trabecular meshwork of human eyes treated with corticosteroids.

OBJECTIVES: To study the ultrastructure of the trabecular meshwork in human eyes with corticosteroid-induced glaucoma and to determine whether the changes noted also occur in the eyes of patients with primary open-angle glaucoma (POAG) who have been treated with corticosteroids. METHODS: The trabecular meshwork from 5 patients in whom corticosteroid-induced glaucoma was diagnosed and from 6 patients with POAG who had been treated with systemic or topical corticosteroids for months to years was investigated with light and electron microscopy. None of the eyes with POAG were considered to have corticosteroid-induced elevation of the intraocular pressure. RESULTS: Eyes with corticosteroid-induced glaucoma had the accumulation of extracellular material distinct from the sheath-derived plaques typical of POAG. A finger-printlike arranged material resembling basement membranes (FBM material), considered characteristic of corticosteroid-induced glaucoma, was found in all eyes with corticosteroid-induced glaucoma. In addition, an abnormal accumulation of densely packed, fine fibrils immediately beneath the inner wall endothelium of Schlemm's canal was present. The findings were similar among patients receiving topical or systemic treatment and among patients of different ages. In the eyes from donors with POAG who had been treated with corticosteroids, the fine fibrillar material and FBM material were present in small amounts in 3 of 6 donors and were not found in the other 3 donors. CONCLUSIONS: The extracellular material that accumulates in eyes with corticosteroid-induced glaucoma differs from that seen in eyes with POAG. Eyes with POAG exposed to long-term corticosteroid treatment did not all respond with the formation of the abnormal extracellular materials characteristic of those found in eyes with corticosteroid-induced glaucoma.

Adolescent↗

PubMed1997

Inhibition of corneal allograft reaction by CTLA4-Ig.

BACKGROUND: Activation of T cells requires both the interaction of T-cell receptor with major histocompatibility complex on the antigen-presenting cell and costimulatory signals, for instance the B7 antigens expressed on antigen-presenting cells and the CD28 molecule expressed on T cells. A recombinant fusion protein, CTLA4-Ig, has been produced that contains the extracellular domain of human CTLA4 fused to IgG1 constant region and that binds the B7 molecule with high affinity. Blocking the CD28/B7 interaction with CTLA4-Ig inhibits T cell activation in vitro and in vivo. METHODS: We used CTLA4-Ig in a fully MHC-mismatched mouse keratoplasty model. The animals were divided into four groups: (1) no treatment, (2) intraperitoneal treatment with 130 micrograms CTLA4-Ig, (3) intraperitoneal treatment with 300 micrograms CTLA4-Ig, (4) subconjunctival treatment with 290 micrograms CTLA4-Ig. RESULTS: The allograft reaction occurred in untreated animals between days 12 and 16 (mean 13.5). While topical application of CTLA4-Ig seemed to shorten the graft survival (mean 11.6 days) and systemic application of 130 micrograms had no influence (mean 14.0), only intraperitoneal injection of 300 micrograms of CTLA4-Ig prolonged the survival of allografts (mean > 20 days) (P < 0.01). CONCLUSION: CTLA4-Ig prolonged significantly the survival of corneal allografts in a fully MHC-mismatched mouse keratoplasty model, but the small antigen load of the corneal transplant and the anterior chamber-associated immune deviation (ACAID) may have a disadvantage to induce tolerance in this model of CTLA4-Ig therapy.

Abatacept↗

PubMed1997

Calcifying liver metastases in a case of primary lung cancer.

A 50-year-old man presented with primary lung cancer with bone lesions and calcifying liver nodi. Two months after stopping chemotherapy, he died. Autopsy revealed multiple organ metastases. Histologically, the calcified nodi in the liver proved to be affected by tumor metastasis.

Adenocarcinoma↗

PubMed1996

A Sendai virus vector leading to the efficient expression of mutant M proteins interfering with virus particle budding.

A Sendai virus expression vector in the form of a transcribing copy-back defective interfering RNA was constructed and shown to efficiently express a tagged matrix protein in the only context of a Sendai virus infection. In an attempt to identify relevant M protein domains involved in viral assembly and budding, a series of deletion mutants were tested for their ability to bind to cellular membrane fractions. The deletion of a region spanning amino acids 105-137 significantly decreased this binding when the protein was expressed in a system driven by the T7 RNA polymerase away from any other viral proteins. Plus or minus charges were introduced in the hydrophobic portion of a predicted amphiphilic helix in this region, and M proteins with altered membrane binding properties were produced. The genes encoding these mutant M proteins were then inserted in the Sendai virus vector and shown to be expressed at levels similar to that of the endogenous wild-type M protein. The presence of a negative charge in the hydrophobic region of the putative amphiphilic helix prevented the incorporation of the mutant protein into virus particles and appeared to decrease the efficiency of virus particle budding. In contrast, the introduction of a positive charge appeared to increase the M mutant uptake into virions. The use a Sendai virus vector has therefore been shown instrumental in the identification of mutant M proteins interfering with the viral assembly-budding process.

Animals↗

PubMed1996

Orthotopic corneal transplantation in the mouse--a new surgical technique with minimal endothelial cell loss.

BACKGROUND: The murine model of orthotopic perforating keratoplasty is important for studying the allograft reaction, but the small dimensions cause technical difficulties. METHODS: The anterior chamber of the eye of the BALB/c mouse was measured with the confocal microscope and with histological methods. Ten C3H mouse donor corneas each were separated by the conventional technique and by the newly developed "underwater" technique, where the opened donor eye did not lose its shape under water. The corneal endothelium was stained with trypan blue and alizarin red S. Ten BALB/ c (H-2d) mice received a corneal graft taken from a C3H (H-2k) mouse by the underwater technique. RESULTS: The 3.7-mm eye of the BALB/c mouse has a corneal diameter of 3.5 mm. The cornea has a central thickness of 170 microns, the epithelium comprising 30% and the stroma 70%. While none of the corneas separated by the new "underwater" technique evidenced endothelial damage, a 28 +/- 17.0% defect of the endothelial surface was found with the conventional technique. All transplanted corneas were clear when the lids were opened on the 2 postoperative day and clouded between the 7th and 30th days (mean 16.5 days) due to an allograft reaction. CONCLUSION: The newly developed "underwater" technique is superior to the conventional technique, since floating of the very thin donor cornea during the separation procedure prevents endothelial defects by guarding against folds. By enabling reliable keratoplasty in the mouse, this technique facilitates studies on the experimental allograft reaction.

Animals↗

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↗