A commercially available laboratory test for predicting the chemosensitivity of tumor cells is plagued by technical problems and appears to work effectively with only a few types of cancer, according to reports delivered at the 13th International Cancer Conference in Seattle. The Human Tumor Clonogenic Assay (HTCA)— also known as the human tumor stem cell assay—is an in vitro test designed to show whether a specific tumor is sensitive or resistant to a battery of anticancer drugs. In a manner analogous to bacterial sensitivity tests used for assigning antibiotics, HTCA results are now being used by some oncologists to tailor chemotherapy to the needs of individual patients. But a number of tumor types don't grow well—and leukemias and lymphomas don't grow at all—under the culture conditions used in the test. In addition, a National Cancer Institute (NCI) study has shown that HTCA is not sensitive to the effects of six
In case of keratoconus, rigid gas-permeable contact lenses as the correction method of first choice allow for a good visual acuity for quite some time. In a severe stage of the disease with major cone-shaped protrusion of the cornea, even specially designed keratoconus contact lenses are no more tolerated. In case of existing contraindications for intrastromal ring segments, corneal transplantation typically has a very good prognosis.In case of advanced keratoconus - especially after corneal hydrops due to rupture of Descemet's membrane - penetrating keratoplasty (PKP) still is the surgical method of first choice. Noncontact excimer laser trephination seems to be especially beneficial for eyes with iatrogenic keratectasia after LASIK and those with repeat grafts in case of "keratoconus recurrences" due to small grafts with thin host cornea. For donor trephination from the epithelial side, an artificial chamber is used. Wound closure is achieved with a double running cross-stitch suture according to Hoffmann. Graft size is adapted individually depending on corneal size ("as large as possible - as small as necessary"). Limbal centration will be preferred intraoperatively due to optical displacement of the pupil. During the last 10 years femtosecond laser trephination has been introduced from the USA as a potentially advantageous approach.Prospective clinical studies have shown that the technique of non-contact excimer laser PKP improves donor and recipient centration, reduces "vertical tilt" and "horizontal torsion" of the graft in the recipient bed, thus resulting in significantly less "all-sutures-out" keratometric astigmatism (2.8 vs. 5.7 D), higher regularity of the topography (SRI 0.80 vs. 0.98) and better visual acuity (0.80 vs. 0.63) in contrast to the motor trephine. The stage of the disease does not influence functional outcome after excimer laser PKP. Refractive outcomes of femtosecond laser keratoplasty, however, resemble that of the motor trephine.In contrast to the undisputed clinical advantages of excimer laser keratoplasty with orientation teeth/notches in keratoconus, the major disadvantage of femtosecond laser application is still the necessity of suction and applanation of the cone during trephination with intraoperative pitfalls and high postoperative astigmatism.
Background: Histological analysis of two Acanthamoeba keratitis eyes with anterior and posterior segment in ammation and blindness.Methods: Two eyes of 2 patients (age 45 and 51 years) with acanthamoeba keratitis (PCR of epithelial abrasion positive) were analysed.Patients underwent tripletopical therapy (polyhexamethilen-biguanide, propamidin-isethionat and neomycin) with failed recovery, subsequent crosslinking, corneal cryotherapy, repeat penetrating keratoplasties, amniotic membrane transplantations and phacoemulsi cation with posterior chamber lens implantation.The patients developed ocular hypotony with central vein/artery occlusion, retinal/choroidal detachment and had no light perception, therefore, the in amed eyes were enucleated.Histological analysis was performed using haematoxilin-eosin, periodic acid-Schiff and Gömöri-methenamine silver staining.Results: We could not observe acanthamoeba trophozoites or cysts neither in the cornea nor in other ocular tissues.Anterior synechiae was detected in the chamber angle of both globes and lymphocytic in ltration was observed around central retinal artery and vein, associated with brous metaplasia of the retinal pigment epithelium.We found perivascular in ammatory cell in ltration (mainly lymphocytes) in the episclera and around ciliary nerves, when analysing the rst globe.This was associated with non-granulomatous uveitis, cilioschisis and tractional retinal detachment.Cross sections of the optic nerve revealed gliosis and optic nerve atrophy.Histopathologic studies of the second globe revealed a multifocal, nongranulomatous choroiditis with lymphocytic in ltration.Conclusions: In long-standing, recalcitrant acanthamoeba keratitis, uveititis, retinal vasculitis and scleritis may occur and result in blindness, even without further persistence of acanthamoeba trophozoites or cysts.In this stage of acanthamoeba keratitis, systemic immune suppression may be necessary for a longer time period.
