Low-dose-rate ionizing irradiation for inhibition of secondary cataract formation.

INTRODUCTION: Secondary cataract formation limits visual function after cataract surgery. Various experimental methods utilizing the pharmacologic inhibition of lens epithelial cell proliferation have been proposed. However, diffusion into the anterior chamber may lead to damage of corneal endothelial cells. This study evaluated the inhibition of lens epithelial cell proliferation with a capsular bag ring, labeled with a beta-emitting radioisotope. METHODS AND MATERIALS: In vitro studies using rabbit lens epithelial cells were performed to investigate the dose-dependent effect of irradiation. Based on these results, P-32-labeled PMMA rings were implanted into the capsular bag of NZW rabbits in vivo after phacoemulsification. Animals were examined for development of posterior capsule opacification over a period of 12 weeks following surgery. Radiation damage to the surrounding ocular tissue was subsequently analyzed in histologic sections using TUNEL assay and proliferation marker. RESULTS: Irradiation of lens epithelial cells in vitro with >5 Gy resulted in a dose-dependent decrease in the number of cells. BrdU testing demonstrated a near complete inhibition of cell proliferation. In vivo, implantation of P-32-labeled PMMA rings led to inhibition of epithelial cell proliferation and secondary cataract formation but was not able to fully inhibit aberrant differentiation of some remaining cells. Histologic examination showed no evidence of radiation damage of the ciliary body or the corneal endothelium. CONCLUSIONS: Low-dose beta irradiation exhibits the potential for inhibition of lens epithelial cell proliferation both in vitro and in vivo. Further investigation of various nuclides and their radiation profiles is needed to optimize the prevention of posterior capsule opacification due to epithelial cell proliferation.

Lens bisector for silicone intraocular lens removal.

The lens bisector, designed to cut silicone intraocular lenses (IOLs) in the middle so they can be extracted through a 3.0 mm incision, consists of a disposable wire sling that can be pulled into a metal tube. After the IOL is moved into the anterior chamber, the sling is placed over its center and pulled completely into the tube, bisecting the lens atraumatically. The IOL halves are then extracted. A new IOL can be inserted through the same incision.

Polishing methods for the lens capsule: histology and scanning electron microscopy.

Capsule opacification occurs when lens epithelial cells remains on the capsule after extracapsular cataract surgery. The cells divide and form fibers. The best way to prevent opacification is to remove all epithelial cells from the capsule. Our study compared the efficacy of different mechanical polishing methods in eyes in which cataracts were removed by endocapsular phacoemulsification through a miniature capsulorhexis. The capsular bag was polished using one of five techniques: metallic scrapers, silicone scrapers, Rentsch capsule curettes, irrigation/aspiration tip, or ultrasound irrigation/aspiration tip. Then a circular central portion of the anterior capsule was removed and processed for histology and scanning electron microscopy. A control group comprised unpolished central anterior capsules obtained by capsulorhexis before or after endophacoemulsification. The cleanest capsules were obtained by polishing with the ultrasound irrigation/aspiration tip.

[The massive migration out of the Soviet Occupied Zone and the German Democratic Republic]. / Die Massen-Migration aus der SBZ und der DDR

PIP: This article is a review of research on mass migration from the Soviet Occupied Zone and the German Democratic Republic to the Federal Republic of Germany during the 1950s. The various official sources of migration statistics are first described, and the extent of politically motivated migration is assessed. The sociological consequences of this migration are then examined, and individual migration motives are briefly considered.^ieng

Evidence for an excited hyperon state in pp --> pK+Y0*.

Indications for the production of a neutral excited hyperon in the reaction pp --> pK+Y0* are observed in an experiment performed with the ANKE spectrometer at COSY-Jülich at p(beam) = 3.65 GeV/c. Two final states were investigated simultaneously, viz. Y0* --> pi+X- and pi-X+, and consistent results were obtained in spite of the quite different experimental conditions. The parameters of the hyperon state are M(Y0*) = (1480 +/-15) MeV/c2 and gamma(Y0*) = (60 +/- 15) MeV/c2. The production cross section for Y0* decaying through these channels is of the order of few hundred nanobarns. Since the isospin of the Y0* has not been determined here, it could either be an observation of the sigma(1480), a one-star resonance of the Particle Data Group tables, or, alternatively, a lambda hyperon. Relativistic quark models for the baryon spectrum do not predict any excited hyperon in this mass range and so the Y0* may be of exotic nature.

Near-threshold production of phi mesons in pp collisions.

The pp-->ppphi reaction has been studied at the Cooler Synchrotron COSY-Jülich, using the internal beam and ANKE facility. Total cross sections have been determined at three excess energies epsilon near the production threshold. The differential cross section closest to threshold at epsilon=18.5 MeV exhibits a clear S wave dominance as well as a noticeable effect due to the proton-proton final-state interaction. Taken together with data for ppomega production, a significant enhancement of the phi/omega ratio of a factor 8 is found compared to predictions based on the Okubo-Zweig-Iizuka rule.

Precision measurement of the quasifree pn-->dvarphi reaction close to threshold.

The quasifree pn-->dvarphi reaction has been studied at the Cooler Synchrotron COSY-Jülich, using the internal proton beam incident on a deuterium cluster-jet target and detecting a fast deuteron in coincidence with the K+K- decay of the varphi meson. The energy dependence of the total and differential cross sections are extracted for excess energies up to 80 MeV by determining the Fermi momentum of the target neutron on an event-by-event basis. Though these cross sections are consistent with s-wave production, the kaon angular distributions show the presence of p waves at quite a low energy. Production on the neutron is found to be stronger than on the proton but not by as much as for the eta meson.

[Flight and exit from the German Democratic Republic: a comment on a familiar topic]. / Flucht und Ausreise aus der DDR: ein Beitrag zum "Wohlbekannten".

PIP: The author discusses population movement out of the German Democratic Republic since 1945 and critically evaluates the sources of migration statistics. These include the official population statistics of the German Democratic Republic, official migration statistics from the Federal Republic of Germany, West German data acquired through the processing of refugees, and migration data from the West German population censuses of 1961 and 1970. Reasons for migrating, political motivation and implications, and the socioeconomic aspects of East-West migration are discussed.^ieng

[Photochemotherapy and cataract formation]. / Photochemotherapie und Kataraktbildung.

According to the literature combined treatment with 8-MOP and UVA has induced ocular damage in animals. Similar changes in humans on photochemotherapy have not yet been reported and therapeutic doses are considerably lower than the doses that proved toxic for the animal eye. The present paper reviews pertinent literature on the subject and discusses the conditions under which photochemotherapy for psoriasis seems acceptable in view of present day knowledge.

[Long-term investigations of the influence of corticosteroids on lens transparency in rats (author's transl)]. / Langzeituntersuchungen über den Einfluss von Kortikosteroiden auf die Linsentransparenz bei Ratten

Both a systemic cortisol treatment (10 mg/kg, daily, s.c.) for 275 days and a local administration of prednisolone eye drops (1%, 4 times daily) for 150 days failed to induce morphologic lens changes in wistar rats. Possible reasons for the different reactions to steroid treatment of human and animal lenses are discussed.

[Effects of acetazolamide (Diamox, Glaupax) on tear production]. / Auswirkungen von Acetazolamid (Diamox, Glaupax) auf die Tränenproduktion.

In view of personal clinical observations, it appeared possible that a therapy with the carboanhydrase inhibitor acetazolamide leads to a reduction of tear production and induces a dry eye syndrome. Tear secretion was therefore measured by Schirmer tests in a control group of 66 patients after cataract surgery and in a test group of 20 patients who were treated with acetazolamide (Diamox, Glaupax) on the day after the cataract operation. The results were subjected to a statistical analysis with 3-factor anova. The cataract operation induced a significant increase of tear flow. Independent of this effect, administration of the carboanhydrase inhibitor caused a significant decrease of tear production, both in the operated eyes and the untouched fellow eyes.

[Further development of a streak retinoscope with calibrated collimator]. / Weiterentwicklung eines Strichskiaskops mit kalibriertem Kollimator.

Development and rationale of a new streak retinoscope have been discussed in an earlier paper. In contrast to classical retinoscopy this retinoscope determines the refraction by forming the narrowest streak in the test person's pupil with a calibrated collimator. In addition to the first prototype the extension of the lamp according to variation of the refraction is measured electronically and the data are transposed into a computer. This allows to freely choose a working distance in a range from about 30 to 120 cm and therefore it is possible to examine restless patients. Accuracy of the measurement was less than or equal to 0.25 D for Ametropia from -0.5 to 5.0 D in a working distance of 30 cm or from -4.0 to -1.5 D in 100 cm. In most persons it is not necessary to use additional glasses during refraction by choosing the adequate distance. Therefore this method can help to refract kids and other persons which could not be refracted by use of glasses. In addition this method excludes the accommodation of the patient as apposed to regular refractometers.

[PUVA treatment and the problem of ocular damage (author's transl)]. / Die Photochemotherapie: Zur Frage ihrer Nebenwirkungen am Auge.

Recently, psoriasis has been shown to respond favorably to PUVA treatment, i.e., local or systemic therapy with a photosensitizer (e.g., 8-methoxypsoralen) and subsequent long UV irradiation. The possibility of this treatment damaging the eye is discussed in the light of various experimental results. As toxic changes only occur when photosensitizer and UVA act jointly, the eyes of PUVA-treated patients must be shielded from any ultraviolet exposure by UV-absorbing protective glasses with side shields. Such glasses should have no significant absorption in the visible range. The new Spectra Shield process enables lenses to be coated in such a way that virtually no UV or IR radiation is transmitted.

[Lens induced myopia in steroid cataracts (author's transl)]. / Linsenmyopie bei der Steroidkatarakt.

Longterm investigations of patients on immun-suppressive corticosteroid therapy showed that the development of advanced corticosteroid cataracts is accompanied by a marked increase of lens myopia up to 7.5 dpt. It can be assumed that this phenomenon is due to the optical effect of the discoid posterior subcapsular opacities.

[Fistulating operations with Walser's punch Modifications without scleral flap and with fixed or loose scleral flap (author's transl)]. / Fistulierende Operationen mit Walser-Stanze Modifikationen ohne Skleradeckel, mit fixiertem und mit nicht fixiertem Skleradeckel.

Long term results of fistulating operations with Walser's punch are reported. A comparison between two methods without and with fixed scleral flap shows that the first method was more often associated with hypotonia, while the latter is more often followed by unsatisfactory pressure regulation necessitating additional drug therapy. That is why a third method of operation was developed. Here the scleral flap is shortened by scissors and not resutured to the sclera. The first clinical results indicate that the method makes use of the advantages of a scleral flap with less risk of an insufficient pressure regulation.

[Cataract during intermittent hemodialysis. The influence of hypocalcemia on the development of opacities (author's transl)]. / Katarakt bei intermittierender Hämodialyse. Uber die Bedeutung einer Hypokalzämie für die Trübungsentwicklung

Twenty uremic patients on intermittent hemodialysis were followed up for lens changes over 4-53 months. Only one patient of 22 years with megaureters and megacystis developed bilateral anterior and posterior subcapsular cataracts during dialysis treatment. The morphology of these cataracts was similar to that of fresh hypocalcemic opacities. The patient had actually been hypocalcemic before the onset of the opacification. Possible reasons for the development of hypocalcemic cataracts during intermittent dialysis might be: 1. a reduced calcium-phosphate ratio due to phosphate accumulation, 2. a decrease of ionized calcium due to removed metabolic acidosis, and 3. a permissive effect of longer latencies.

Rat lens epithelial cells in vitro. I. Observations on aging, differentiation and culture alterations.

Lens epithelial cells from rats aged 5 days were grown in long-term cultures. These cells age, differentiate and transform spontaneously. Morphological observations indicate five different stages (A-E). The epithelial character is lost after the first two passages. Elongated cells appearing afterwards are considered as cells that have started differentiation to fiberlike cells. Big flattened cells are considered as senescent cells that have lost theie proliferative capacity. Data from population kinetics also reflect these five stages. Chromosome analysis shows that three of the five stages are no longer diploid. Two alternative modes of spontaneous transformation are possible. The proliferative capacity of rat lens epithelial cells is higher than that of rat embryonic fibroblast systems.