[Intraocular involvement of Chagas disease (American trypanosomiasis). Studies in Paraguay/South America]. / Beteiligung der Chagas-Krankheit (Amerikanische Trypanosomiasis) am inneren Auge. Untersuchungen in Paraguay/Südamerika.

BACKGROUND: In Central and South America, Chagas' disease is of great epidemiologic importance. The epidemiologic agent is represented by Trypanosoma cruzi, a monocellular parasite, instrumental in human infection is the presence of vectors, which are various species of hematophagous bugs. The eye is one of the most important entrance sites of the parasite, and relatively little information about the relationship between Chagas' disease and eye complications is available. PATIENTS AND METHODS: We examined 79 chagasic patients in order to detect changes in the retina. As a control group, we examined 48 patients with negative serology within the same age range and from the same regions. For every patient we completed a routine ophthalmologic examination, with inspection of the retina using direct and indirect ophthalmoscopy. RESULTS: In most of the chagasic patients, the ocular fundus was unobtrusive; in only 6 out of 79 cases (7.6%) we did observe small parafoveolar retinal pigment epithelium defects and in 1 case (1.3%) distinct pigment epithelium atrophy of the posterior pole. No comparable findings were observed in the control group. CONCLUSION: Compared with the examination results of the control group, in the patients with intermediate and chronic Chagas' disease we observed an accumulation of retinal pigment epithelium defects, which, however, did not cause a significant loss of vision.

[Risk factors for surgical failures in rhegmatogenous retinal detachment]. / Risikofaktoren für operative Misserfolge bei rhegmatogener Netzhautablösung.

BACKGROUND: The evaluation of further risc factors predesposing failure in retinal detachment surgery than those already known to be associated with PVR was the goal of this retrospective study. PATIENTS AND METHODS: The data from 130 cases with unilateral rhegmatogenous retinal detachment treated initially with buckling procedures, were retrospectively reviewed to investigate pre-, intra- and postoperative factors which may predispose anatomical failure in retinal detachment surgery. None of the selected consecutively operated eyes had risk factors, which have already been associated with an unfavourable outcome, such as the presence of preoperative macular holes, PVR or assumed PVR-inducing factors, such as ocular trauma, giant retinal tears, vitreous hemorrhage, previous vitrectomy, cryopexy and laser photocoagulation. RESULTS: The anatomic success rate after scleral buckling procedures was 78.5% and the overall success rate after multiple surgery including vitrectomy increased to 94.6%. 102 (78.5%) cases, treated with a maximum of two scleral buclking operations were statistically compared to the 28 cases which needed further vitreoretinal surgery. The statistical analysis revealed as preoperative risk factors for failure in rhegmatogenous retinal detachment surgery 1) retinal detachment exceeding two retinal quadrants (p < 0.05) and 2) size of the retinal tear larger than 60 degrees (p < 0.05), whereas postoperative risk factors were 1) presence of subretinal hemorrhage (p < 0.01) and 2) persistent subretinal fluid at least two days after surgery (p < 0.01). Eyes with preoperative visual acuity less than 0.1, pseudophacic eyes with posterior chamber intraocular lenses and eyes with severe intraoperative hypotony also showed a tendency to unfavourable outcome, but without a statistically significant level. CONCLUSIONS: Possible ways of interfering in the retinal reattachment process and the clinical importance of these evaluated factors are discussed. They should be taken in consideration for the prognosis of the postoperative anatomical result and treatment modalities if further surgery is required.

Distribution of tissue polypeptide antigen (TPA) in normal human tissues: Immunohistochemical study on unfixed, methanol-, ethanol-, and formalin-fixed tissues.

The distribution of tissue polypeptide antigen (TPA) was studied in unfixed, methanol-, 95% ethanol-1% acetic acid (EA)-, and formalin-fixed paraffin-embedded sections of all adult human tissues using an indirect immunoperoxidase method. The specific staining patterns were virtually identical in unfixed and alcohol-fixed tissues, but in formalin-fixed tissues this similarity was found only after fixation for up to 24 hr and pretreatment with protease for 15 min. Although prolongation of formalin fixation beyond 48 hr increasingly diminished the TPA reactivity, TPA could still be demonstrated in tissues fixed in formalin for up to 6 months. TPA was found to be a cytoplasmic constituent of almost all adult human duct and cavity lining, simple, and stratified epithelia. TPA was not demonstrated in epidermis, renal proximal convoluted and testicular tubules, basket-like myoepithelial cells, nor in most glandular acini, including hepatocytes and pancreatic acinar cells. The TPA staining was also negative in all non-epithelial tissues, including lymph nodes and bone marrow. The well-defined epithelial distribution and the comparable demonstrability in differently preserved tissues make TPA a useful tool for the identification of cells of epithelial character.