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Biomedical subjects

G Grabner

Publications and source records attributed to G Grabner.

At least 37 records · Page 2Linked to original sources

[Acanthamoeba keratitis--a too seldom diagnosed disease?].

Acanthamoeba keratitis has become a difficult diagnostic and management problem in contact lens patients over the last few years. A young female contact lens wearer presented with a long history of painful central corneal ulcer. The suspected diagnosis of Acanthamoeba keratitis could only be confirmed by histology and electron microscopy following penetrating keratoplasty. Special stains of scrapings and culture of material on special media failed to establish the diagnosis. This rare (or underdiagnosed?) infection must be considered in the differential diagnosis of keratitis following contact lens wear.

Acanthamoeba

[Hydrogel posterior chamber lenses--an improvement?].

Although the design of PMMA intraocular lenses has reached a stage of sophistication at which further modifications are unlikely to result in any major improvements in implant surgery, new materials with possibly improved mechanical and biologic properties should be evaluated carefully. The hydrogel lens (containing 38% poly-HEMA) is a soft, flexible, hydrophilic "single-piece" posterior chamber lens which could help to minimize intraoperative and postoperative IOL trauma. Fifty hydrogel intraocular lenses were implanted during a ten-month period using a standard extracapsular cataract extraction technique. Implantation was considered easy in most cases. As regards biocompatibility, stability of lens position, and visual acuity, the postoperative results are promising. In the follow-up period reported on, no central opacification of the posterior lens capsule was observed.

Aged

Local texture analysis: an approach to differentiating liver tissue objectively.

The usefulness of local textural analysis in identifying diseases of the liver has been evaluated. In comparing two areas texturally, a random distribution of one or several textural parameters indicates identical tissue, whereas a distinct clustering can be used to discriminate between different tissues. Using this procedure, various diseases of the liver were differentiated accurately whereas different images of the same state of the liver were classified as similar with high accuracy. The consistent results with different patients, sections, sample locations and scanner parameter settings demonstrate that these factors have no impact on the characteristics of the resulting pattern used for discrimination and therefore for the final diagnosis. The overall diagnostic accuracy of this method seems better than conventional sonographic evaluation of parenchymal liver disease and at least competitive with other computerized methods described. The most important result clinically seems to be the high accuracy in differentiating between hepatitis and normal liver, which cannot be achieved by conventional ultrasonography.

Adult

[New methods of refractive corneal surgery. Experimental studies].

In an experimental study the surface characteristics of two fundamentally different lamellar corneal dissection techniques were compared. Using porcine corneae, 9.5 mm lenticles were cut from the whole globe and evaluated by SEM. With an oscillating blade, a smooth cut surface was found in most cases with occasional irregularities. The rotating lamellar keratome had uniform cutting characteristics with a somewhat wavy surface structure, which has not so far been observed in human tissue. By increasing the speed of rotation and decreasing the rate of advance of the blade the surface structure was improved. The two cutting principles and their possible clinical applications are discussed.

Animals

[Why HLA-typing in keratoplasty? A review].

Due to the absence of vessels and lymph drainage, human cornea is the tissue grafted with the greatest success. From an immunological point of view, this advantage is lost when the recipient cornea has pronounced vascularization and is sensitized. In such cases, which have a poor prognosis, the postoperative success rate drops to below 50% due to graft rejection. The origin and point of attack of the immune reaction to the graft are the MHC antigens of the donor cornea, which occur on almost all nucleated cells. Since they are capable of triggering a T cell activation in the recipient they set immunological effector mechanisms in motion which lead to elimination of the cells carrying the alloantigen. Corresponding to the MHC antigen expression (both Class I as well as Class II) on all cells in all layers of the cornea, rejection reactions of all the various cell types (epithelial, stromal, endothelial) are also seen. By using histocompatible donor corneas it is possible to influence the afferent arm of the immune response preoperatively and thus to diminish its effect on the postoperative course.

Corneal Transplantation

[Differential effect of incompatibilities of the HLA-A and HLA-B locus on the success of corneal transplants].

The positive influence of HLA-compatible donor material on successful transplantation was proven especially for prognostically unfavourable cases. Nevertheless it is not clear whether varying importance should be attached to the antigen incompatibilities at the HLA-A and HLA-B locus. 62 keratoplasty patients, 37 of whom had primarily poor prognoses and 25 patients with low risk of transplant rejection were prospectively given transplants in which more than two certain incompatibilities at the HLA-A and HLA-B locus had been ruled out. The number of Ag incompatibilities (separately according to locus) was related retrospectively to postoperative progress. An irreversible transplant failure had occurred in 6 patients (16%) four months after surgery in the high-risk group, whereas 31 transplants (84%) remained clear. The course of healing was without complications within the first four months in all patients with favourable starting position. The influence of the HLA disparities on transplantation success was examined by means of the chi-square test. Taking the Ag incompatibilities of both loci in combination into account showed an only marginally significant (p = 0.1) influence on the survival rate of the transplant. Here HLA-A incompatibilities appear to have only secondary significance, whereas incompatibilities at the HLA-B locus correlated inversely (p = 0.02) with the success of transplantation.

Chromosome Mapping

[Keratomycosis caused by Candida albicans].

A 78-year-old female patient developed mycotic keratitis in her right eye three months after penetrating keratoplasty. Multiple myeloma is presumed to have been the predisposing factor. Candida albicans was isolated from the aqueous humor at the time of surgery. Treatment consisted of systemic ketoconazole (p.o.) and miconazole (i.v.); miconazole eye drops were applied topically and amphotericin B was instilled into the anterior chamber. Resolution of the corneal infection was ultimately achieved with this therapy.

Aged

[Chemotherapy of advanced pancreatic cancer with 5-fluorouracil, doxorubicin and high-dose methotrexate].

The aim of the present phase II clinical trial was to investigate the therapeutic efficacy and tolerance of a combination chemotherapeutic protocol consisting of 4-weekly intervals of 5-fluorouracil, doxorubicin and high-dose methotrexate (FAMeth-regimen) in patients with advanced measurable pancreatic cancer. After a median treatment duration of 4 (2-12) months, one complete and one partial response were achieved in the 13 evaluable patients. Two additional patients had evidence of objective tumour regression, although response was less than 50% of pretreatment tumor measurements. Stable disease was noted in 3 patients, and the tumour progressed in 6. The median survival of all evaluable patients from start of therapy is 7 (2-17) months. Side-effects associated with FAMeth-chemotherapy were generally mild and reversible and primarily included gastrointestinal symptoms (38%) and leukopenia (62%). There was 1 treatment related death due to pancytopenia and sepsis. Our preliminary data suggest some antitumour activity of the regimen against pancreatic cancer, although final assessment of therapeutic results must await accrural of additional patients.

Adult

Search for improved culture conditions for clonogenic growth of human colorectal cancer cells in vitro.

In order to analyze and define potentially better growth conditions for colonic stem cell proliferation, we chose four established human colorectal cancer cell lines that differed in biologic cell properties. We studied variables of standard cloning conditions including culture medium, serum supplement, solidifying agent, addition of specific growth factors and use of capillaries as an alternative culture vessel. While modulation of serum concentration as well as use of various standard formulations of culture base media did not result in a reproducible increase of plating efficiencies (PEs), a significant increase in colony formation (when compared to the conventional assay procedure) was achieved; by use of 0.3% agarose or boiled agar as semisolid matrix and by culturing of cells in enriched 'GMF medium'. Specific growth factors, such as EGF or glucagon resulted in "occasionally better" in vitro growth. This suggests a retention of the ability of cells in culture to respond to physiologic regulators of growth. To verify and extend these initial results obtained with continuous cell lines, growth enhancing modifications of the original cloning technique were subsequently applied to in vitro growth of 15 human colorectal cancer specimens obtained directly from patients. Specimens that grew 30 or more colonies under standard plating conditions displayed a more than two-fold increase in PEs which was reproducible for the two specific variables mentioned above, but the overall success rate of the assay could not be improved. In addition to the possibility that several deficient basic requirements for achieving optimal environmental conditions for colonic stem cell growth have not been defined, we believe a major reason for failing to improve the number of drug-assayable specimens is related to an inherent interneoplastic diversity in terms of growth requirements of human colorectal malignancies.

Cell Line

Survival and quality of life in 23 patients with severe aplastic anemia treated with bone marrow transplantation (BMT).

Survival and quality of life are reported in 23 pretransfused patients with severe aplastic anemia (SAA) who underwent bone marrow transplantation (BMT). The projected survival is 76% with 18 of 23 patients being alive 332 to 1677 days post graft (median: 842). 5 patients died between day 4 and 416. 12 of 17 patients at risk developed chronic graft versus host disease (GVH-D). 4 of these patients have a diminished quality of life due GVH-D related disabling manifestations. Autologous haemopoietic recovery was excluded in all patients by the demonstration of haemopoietic chimerism. We recommand age-adapted rejection prophylaxis; such strategy may help to diminish disabling graft versus host disease in otherwise haematologically reconstituted survivors.

Adolescent

[New central, epithelial iron deposit following epikeratophakia in high-grade myopia].

Following epikeratophakia for the correction of myopia an epithelial iron dot was observed in the center of the lenticule as early as five months following surgery. Biomicroscopic examination of 55 cases revealed indistinct borders, a yellow to dark brown coloration and a localization in the deep epithelial layers. It was apparent in 100% of the patients one year after surgery, with no tendency to regression over a follow-up period of up to 23 months, and did not appreciably affect postoperative visual acuity. The occurrence of this iron dot is attributed to a localized pooling of tear fluid in the centrally flatter optical zone of the lenticule, since it was not seen in patients who underwent surgery for aphakia or keratoconus.

Adult

[Candida retinitis following gastrectomy].

The authors report on a 68-year-old patient who developed disseminated retinochoroiditis and vitritis following extensive gastrectomy for a cardial carcinoma. The clinical diagnosis of an endogenous Candida infection was confirmed by positive identification of Blastomyces from the subclavian catheter tip and the antibody titer. Resolution was achieved with orally administered ketoconazole and intravenously administered miconazole therapy.

Aged

[Toxic contact dermatitis in hairdresser trainees: study of therapy with steroid-free, pH-stabilized emollients].

In a pilot study on 869 trainee hairdressers eczematous changes of the hands, presenting as chronic toxic contact eczema, were found in 42-55% of the investigated persons. In a subsequent therapeutic study involving 144 trainee hairdressers who had marked chronic toxic contact eczema, it was shown that regular use of pH-stabilized creams and ointments and use of non-alkaline soaps are effective and the use of cortisone ointments should not be necessary. It was demonstrated that 70% of the probands showed clear improvement in eczematous changes as controlled by colour changes in the nitrazine yellow test. However, 30% of those investigated were not thought to be able to continue as hairdressers. These results enable early detection of persons in whom a change of occupation seems indicated. Furthermore, treatment of young persons permits maximal curative changes and represents a model of preventive medicine in dermatology.

Acid-Base Equilibrium

Effect of timolol on aqueous humor protein concentration in the human eye.

We performed a double-masked, controlled study investigating the increase in the protein concentration in aqueous humor after topical timolol maleate administration. Forty patients scheduled to undergo intracapsular cataract surgery were included in the study. Either timolol ophthalmic solution or the vehicle of timolol alone (control) were applied topically in a randomized fashion, and aqueous humor was collected during surgery. Protein concentrations were determined by gel-filtration chromatography. The total protein concentration as well as the concentration of high and medium molecular weight proteins were significantly elevated in the timolol-treated group. The relation of the levels of the three different molecular weight classes did not differ significantly between the two groups, indicating that undisturbed protein filtration in the face of reduced aqueous humor production--and not a change in the permeability of the blood-aqueous barrier--is responsible for the increase in concentration.

Aqueous Humor