Persistent organic pollutants in agricultural soils of central Germany.

Concentrations of persistent organic pollutants (HCHs, DDX, PCBs and HCB) were measured in topsoils from 11 agricultural fields in the lee of large disused industrial plants in the Leipzig-Halle region at varying distances from emitters. The investigations clearly indicate the deposition of anthropogenic pollutant inputs, not only in the past, but also today. The pollution potential was assessed on the basis of current guide values and limits, as well as in relation to values found in agricultural soils elsewhere in Germany, in Europe and in the USA. The reference values were mainly exceeded for DDX and gamma-HCH (lindane). The PCB pattern was determined and the degradation ratios between the parent substances and their metabolites (DDX and HCH isomers) were calculated in order to distinguish between the previous and current pollutant input of pesticides by means of principal component analysis.

Correlation of aerobic biodegradability of sulfonated azo dyes with the chemical structure.

The reported data of biodegradability of variously substituted 25 sulfonated azo dyes were divided into two classes: 8 dyes designated "rapidly biodegradable" and 17 dyes "not rapidly biodegradable", by applying principal components analysis (PCA). The biodegradability of the dyes was modeled with the discriminant technique of two-value regression analysis based on structural descriptors. A statistically significant and biologically meaningful regression model that gives perfect classification was obtained, and the results were compared with the previous qualitative interpretation of the substituent effects on biodegradation. The coefficients of the regression model revealed a significant interaction between ring substituents for biodegradability. The results facilitate understanding of the mechanism of degradation.

[Single step implantable plate-haptic silicone lenses using the Passport system--initial experiences and results]. / Mittels Passportsystem einhändig implantierbare Plattenhaptik-Silikonlinsen--Erste Erfahrungen und Ergebnisse.

BACKGROUND: A new IOL implantation technique introduced in Germany since December 1995 is presented--the one-piece-plate-haptic silicone lens implantable with the Passport system. METHOD: From January to September 1996 in 291 patients after 3.2 mm clear cornea incision, capsulorhexis, phacoemulsification and implantation of an one-piece silicone posterior chamber lens with an implantation system was performed. The early post-operative results like visual outcome, astigmatism and complication rate are presented and compared to a group of 100 patients with implanted foldable three-piece silicone posterior chamber lenses. RESULTS AND DISCUSSION: The first post-operative day no statistically significant differences in visual outcome (mean: one-piece 0.71; three-piece 0.69), in absolute astigmatism (mean diopter 0.82 one-piece; 0.91 three-piece), in axial position and in complication rate were detectable. Differences of this new implantation technique compared to the conventional technique are discussed. CONCLUSION: The implantation of one-piece silicone lenses with the Passport system is a reliable and high quality alternative to conventional systems.

"IR-Spectroscopy" - computer-program for the interpretation of infrared spectra.

A computer-program "IR-Spectroscopy" for the interpretation of infrared spectra of organic compounds is described. It contains the following basic items for preprocessing and execution of the computer based interpretation process: handling of the rule-base CorTab, routines for automatic rule generation and interpretation modules on the basis of the programming languages PROLOG and C.

Measurements of retinal microcirculation in retinal vessel occlusion before and after treatment.

Blood flow, arterial velocity, and vascular diameter were measured in patients with retinal vessel occlusion before and after treatment, especially after light coagulation. The mean values in the patient group showed significantly reduced blood flow and velocity compared to the normal group. The mean group difference before and after therapy revealed that while there is an increase in blood flow after treatment, the normal value is not reached. Individual patient values indicated both increased and decreased blood flow and velocity after treatment as compared with the values before therapy. There are various stages in microcirculatory disease and the microcirculation also behaves differently after treatment, which could be observed by measurement in vivo of the physiological flow parameters.

[Clinical interpretation of retinal circulatory measurements. IV. Photocoagulation in diabetic retinopathy and venous occlusive diseases]. / Klinische Interpretation retinaler Durchblutungsmessungen. IV. Fotokoagulation bei diabetischer Retinopathie und venösen Verschlusserkrankungen.

Based on the pathomechanism of diabetic retinopathy, the effect of photocoagulation on retinal microcirculation as assessed by measurements of retinal microcirculation magnitudes is discussed. The clinico-experimental results support the opinion that an essential effect of photocoagulation is due to an improvement in the flow conditions of the noncoagulated central retinal area with regard to metabolic exchange and stasis situation by the coagulation-induced occlusion of peripheral capillary areas. Further clinico-experimental measurements of retinal microcirculation magnitudes for the assessment of the behavior of microcirculation after photocoagulation in venous occlusive diseases of the retina are presented. It is shown that retinal microcirculation immediately after photocoagulation reacts by transitory instationary flow conditions; in this period it is quite possible that an additional blood flow reduction over several days will occur. In particular, the effect of photocoagulation in venous occlusive diseases with narrow arterial vessels is discussed. It is emphasized that with regard to the therapeutic effect of photocoagulation as well as to the discussion of pathomechanisms, apart from blood flow, the differentiated behavior of single retinal vascular areas, such as arteries, arterioles, capillaries, venules and veins, requires more attention. Particularly with this in mind, substantial improvements in differential diagnosis and treatment of retinal circulatory disturbances may be expected from measurements of retinal circulation magnitudes.

Measurement of flow-physiologic parameters of retinal blood circulation in type 1 and 2 diabetics before and after photocoagulation.

In seven diabetics of type 1 and seven of type 2, the flow physiologic magnitudes were measured in a retinal quadrant before and after photocoagulation. The segmental blood flow, the arterial flow velocity, and the diameters of artery and vein are smaller after photocoagulation than before. Investigations into the time course of the flow-physiologic parameters following photocoagulation show that the flow-physiologic values are stationary about 2 weeks after photocoagulation.

[Kidney changes in patients with proliferative diabetic retinopathy]. / Nierenveränderungen bei Patienten mit proliferativer diabetischer Retinopathie.

On 42 patients (25 males, 17 females) at the age of 46.1 +/- 13.4 years with a proliferative diabetic retinopathy clinical and laboratory examinations were performed for the proof of a renal lesion. This disease was found in 59.5% of the cases. In the foreground of the pathological findings were a proteinuria, a restriction of the creatinine clearance and of the concentration power of the kidneys as well as the hypertension. The diabetic nephropathy had its peak of frequency between the 50th and 60th year of age and showed significant relations to the duration of diabetes as well as to be early age of manifestation. Close ophthalmological and nephrological examinations, particularly of the juvenile diabetics, should render possible an early recognition and treatment of the diabetic microangiopathy.

[High-dosage combination antibiotic treatment in severe therapy-resistant uveitis and necrotizing (chorio)retinitis]. / Hochdosierte antibiotische Kombinationsbehandlung bei schweren therapierefraktären Uveitiden und nekrotisierenden (Chorio-) Retinitiden.

Twelve patients with extremely severe uveitis and two patients with necrotizing (chorio-)retinitis were treated with a combination of antibiotics consisting of penicillin G, gentamicin and metronidazole. The antibiotics were administered in 5 cases (all uveitis patients) after unsuccessful long-term treatment with other drugs, in nine cases after short-term treatment with other drugs or immediately. The treatment was effective in 10 of the uveitis patients, including all 5 cases in which the previous treatment had been unsuccessful. In 2 cases it was ineffective. It was effective, however, in both of the cases of necrotizing (chorio-)retinitis. The duration of the required treatment with antibiotics was not significantly prolonged in cases which had previously undergone long-term treatment with other drugs. However, the clinically detectable onset of improvement of vision and of the findings was significantly delayed. Despite some cogent connections between the antibiotics therapy and the improvement in the clinical picture, no well-founded conclusions as to etiology can be derived for the uveitis or necrotizing (chorio-)retinitis patients in question. The successful treatment of problematic cases identifies therapy with antibiotics as a therapeutic alternative.

[Androgen regulation in patients with diabetic retinopathy]. / Zur Androgenregulation bei Patienten mit diabetischer Retinopathie.

In 21 male diabetics (juvenile onset diabetes) with diabetic retinopathy and 13 patients without this condition, the HCG and the LH-RH stimulation tests were performed and the results compared to those of 20 persons with normal metabolism and full vision. The findings can be interpreted as hypothalamic hypophysogonadal dysregulation in case of lowered basal testosterone, significantly inverse correlation to the relative responsiveness of Leydig's cells, lacking correlation between LH and testosterone as well as normal LH-RH test. Differences between patients with and without retinopathy were not detectable.

[Cryotherapy in vernal conjunctivitis]. / Kryotherapie bei Conjunctivitis vernalis.

Twenty five patients (mostly boys between the ages of nine and 14) suffering from vernal conjunctivitis were treated by cryotherapy. Three cryocycles, each of one to two minutes' duration, consisting in contact freezing at -160 degrees C, were performed under local anesthetic. There was very rapid regression of the acute inflammatory symptoms within a few days. At the same time, the eosinophil count in the smear preparation decreased considerably. The "cobblestones" only flattened out in the course of several weeks, following repeated sessions.

[How effective is photocoagulation? (author's transl)]. / Was vermag die Fotokoagulation und was bewirkt sie?

Six hypotheses relating to the mode of action of photocoagulation, based on comprehensive data gathered from the literature, are put forward and discussed. Particular emphasis is given to the question of achieving a lasting break through of the barrier represented by Bruch's membrane and the pigment epithelium and thus to the altered diffusion conditions between the choriocapillaries and the retina. In addition a peculiar marginal fluorescence in fluorescein serial angiograms of old light coagulation foci is described and compared with data from the literature. The authors put forward a new hypothesis concerning the mode of action of light coagulation; they believe that particularly in the marginal areas affected by photocoagulation, completely new conditions are created for the metabolic exchange between choroid and retina, including the formation of anastomoses and shunts.

[Microcirculation disturbances at the onset of diabetic retinopathy. New therapeutic procedures? (author's transl)]. / Mikrozirkulationsstörungen bei beginnender diabetischer Retinopathie. Neue Wege in der Therapie?

The generalized capillary dilatation demonstrable at the early stage of diabetic retinopathy can now, on the basis of recent results in biochemistry, be assessed as an attempt at autoregulation in relative hypoxia of tissue. In patients with diabetic retinopathy, an elevated HbA1c concentration in the blood can be observed. The DPG level, however, is reduced. Both facts cause reduced oxygen transmission from blood to tissue. Rheologic changes such as augmented aggregation of erythrocytes, decreased deformability of erythrocytes and increased viscosity of blood and plasma finally lead to disturbances of microcirculation in the terminal vascular system. From these latest findings concerning the development of microcirculation disorders in diabetic retinopathy possible consequences for new therapeutic procedures can be derived.

[Experiences with the 32P test in tumor diagnosis]. / Erfahrungen mit dem 32P-Test bei der Tumordiagnostik.

A report on results of 186 32P tests is given. Radiation increases of more than 30%, compared with tumor-free areas, were considered as positive. 95 eyes were histologically examined. The 32P test gave 90 correct positive answers and 1 correct negative answer. Faulty positive results were found in 2 cases; faulty negative results were also found in 2 cases. This means that the diagnosis was correct in 95%. The literature is discussed concerning reliability and methods. The dangers of the use of 32P are stressed, and the development of noninvasive nuclear-medical diagnostic methods is suggested.

[Device for measurements of blood flow in the great retinal vessels of man (author's transl)]. / Messungen zur Ermittlung des Blutvolumendurchflusses in grossen retinalen Gefässen des Menschen.

A combined measuring unit for the Retinophot is described which can be used to determine the blood flow through the great retinal vessels. This method is possible by combination of the two-point photometry with length measurements by means of rocking-plate micrometry. The first measuring results are presented.