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Biomedical subjects

B Riss

Publications and source records attributed to B Riss.

At least 19 recordsLinked to original sources
PubMed1999

Quantification of re-evaporated mass from loaded fibre-mist eliminators.

Airborne lubricant emissions are a serious health hazard for employees in the metal working industry. The basic components of lubricants are oils and additives for adapting the properties to achieve the process demands. The oils used in lubricants are either mineral, synthetic or of biological origin. The lubricants are used as water-emulsions and also as straight oils. Extreme process conditions cause considerable amounts of aerosol and vapour emissions of lubricants into the working environment. Fibre filters are used in industrial demisters for pollution control and also for sampling purposes. Re-evaporation of separated lubricants from loaded fibre filters causes increased vapour emissions. Quantification of lubricant vapour emission was the subject of this research. An apparatus and an appropriate procedure for measuring the dynamic behaviour of evaporative losses from fibre filters were developed. The test piece of a loaded fibre filter was fixed in a sampling probe according to VDI 2066. The vapour concentration of organic compounds in downstream air was measured in real-time by using a photo-ionisation detector (PID). The PID was checked by sampling the vapour on an oleophilic adsorbent resin, solvent extraction and quantitative IR analysis and also gravimetrically. The two basic processes of filtering volatile aerosols are, on the one hand, collecting droplets on the fibres and, on the other hand, the evaporation of collected liquid. These two processes had to be separated in order to measure the increase of the vapour concentration caused by the tested fibre filter. The experiments were carried out using pure dodecane and hexadecane in order to avoid difficulties due to the unknown chemical composition of lubricant vapour. The variation of the air flow and the initial liquid mass on the filter covered the relevant range for industrial fibre demisters and for sampling methods based on collecting aerosols on fibre filters. It was found that the downstream air was saturated with lubricant vapour for a wide range of filter loads and filtration velocities. From the results obtained it can be concluded that loaded industrial filter systems emit air with saturation vapour concentration throughout their operation. Hence, vapour emissions can be estimated easily if the saturation vapour pressure and the mean relative molecular mass are known. Moreover, results obtained from measurements of filters with low loads confirm that the phase transition from liquid to vapour is influenced by the identified process parameters. This is relevant for measurement methods using fibre filters for sampling volatile aerosols. A semi-empirical model to estimate the evaporative losses for low loadings is proposed. However, further research is necessary to determine the full range of parameters that are relevant for evaporative losses from filters loaded with low masses of aerosols.

Air Pollution, Indoor↗
PubMed1984

[Advantages of sliced silicone sponge in retinal detachment surgery].

A retrospective study was undertaken in order to compare full-thickness sponge with sliced sponge in retinal reattachment operations. In 41 patients (42 eyes) in whom a sliced plug was used, retinal reattachment was achieved in all cases; there were no infections, but lesions of the conjunctiva could not be prevented. In the control group with conventional full-thickness sponge, retinal reattachment was not achieved in 2 out of 28 cases, and in 2 eyes infection occurred, resulting in rejection of the plug. The authors conclude that the results of retinal reattachment surgery are the same with sliced sponge plugs as with full-thickness plugs. The advantages offered by the elastic effect of sliced sponge are reduced danger of rejection, less irritation of the eye and improved patient comfort. Scleral buckles after plugging with sliced sponge are smoother and broader and episcleral support of the retinal defect is adequate.

Adolescent↗
PubMed1984

Inhibition of experimental intraocular proliferation with intravitreous 5-fluouracil. A transmission electron-microscopic study in rabbits.

5-Fluouracil, administered at concentrations of 1 and 5 mg to inhibit experimental intraocular proliferation produced by intravitreously implanted fibroblasts in rabbits, produced tissue alterations revealed by TEM. The degranulation and migration of pigment epithelial cells, the incipient degradation of axons and myelin sheets, the migration of glial cells and the prominent edema of the inner layers indicated a non-negligible damage to the retina, suggesting to abstain from its use in human eyes and to search for less neurotoxic drugs, possessing the same inhibitory effect on intraocular proliferation.

Animals↗
PubMed1983

[Severe changes in the fundus oculi in pregnancy toxemia. 3 cases].

Three cases of severe retinal changes in conjunction with EPH gestosis are presented. 2 patients showed 4th degree hypertensive fundus changes (Keith-Wagener classification) and one suffered from bilateral exudative retinal detachment after an eclamptic fit in the 32nd week of pregnancy. The possible causes of retinal changes and visual disturbances in EPH gestosis are reviewed.

Adult↗
PubMed1983

Inhibition of experimental intraocular proliferation with intravitreal 5-fluouracil.

5-Fluorouracil was used to inhibit experimental intraocular proliferation in rabbit eyes, produced by homologe fibroblast implantation. Two different concentrations were used, 1 and 5 mg in a single intravitreal injection. The eyes were followed up over 4 weeks. Proliferation and resulting traction detachment was reduced from 75% to 30% in the 1-mg 5-fluouracil group. In addition, we observed retinal and vascular changes in a considerable number of eyes treated with 1 mg and much more pronounced alterations in most of the eyes treated with 5 mg fluouracil.

Animals↗
PubMed1983

[Incidence and significance of fundus changes in EPH gestosis].

The authors examined 100 unselected pregnant women with EPH gestosis of different severity using the Keith-Wagener classification. In 52 women no fundus changes were observed; first-degree changes were seen in 32 women and second-degree changes in 10. Six gravidae presented with third or fourth-degree fundus changes. The average gestosis index was almost identical in the group without fundus changes and in the groups with first and second-degree hypertensive retinal changes, but significantly higher in the group with severe fundus changes (third or fourth degree). There was a clear correlation between the hypertensive fundus changes and blood pressure at the time of examination, in particular with regard to systolic blood pressure. An apparently normal fundus did not exclude the presence of a severe EPH gestosis; on the other hand severe retinal changes were sometimes seen in women with only mild EPH gestosis. Examination of the fundus in patients with EPH gestosis permits an objective assessment of vascular changes and provides a basis for further obstetric management.

Adult↗
PubMed1983

Advances in intraocular techniques in the treatment of retinal detachments arising from holes of the posterior pole.

Two groups of retinal detachments arising from macular holes were compared. The first group consisted of 27 consecutive cases operated upon during the years 1972-7 by various techniques (encircling and hemi-encircling procedures, scleral resection, scleral pocket, and silver clip). The second group consisted of 18 consecutive cases operated upon in the years 1978-81 by pars plana vitrectomy to release vitreous traction or make intraocular manoeuvres possible. In all cases of the second group an intraocular gas bubble was used to tamponade the macular hole, and the hole was coagulated only if necessary. There was not only a significantly better anatomical result in the second group, but the functional results were more favourable. Two-thirds of the eyes of the second group reached a visual acuity between 6/12 and 6/48, while in the first group none of the eyes gained a better vision than 6/60. The reading vision in 2/3 of the first group was negligible, while nearly half of the cases in the second group reached useful acuity between Jaeger 3 and 10.

Female↗
PubMed1982

[Value of echography for diagnosis and follow-up of perforating eye injuries].

The introduction of vitreous surgery with its multiple capabilities of intraocular manipulations makes it possible to operate on cases which had been considered as hopeless up to now. With these techniques the importance of ultrasonic examination increased especially in cases with severe perforating injuries and their follow-up, to detect the onset of intravitreal fibrosis and early traction detachment, when no fundus view is possible. An other indication for ultrasonic examination is the exact localization of foreign bodies. Out of 484 perforating injuries which were examined and treated in our clinic during the last 10 years, ultrasonographic diagnosis was helpful in 18% and had further therapeutic consequences: In 24% a detachment operation or vitreous surgery was necessary, in 30% ultrasonography showed severe damage and surgery was considered to be ineffective. 42% were follow-up examinations of the posterior segment.

Equipment Design↗
PubMed1982

[Corneal sensitivity in diabetes mellitus].

We measured corneal sensitivity in 30 eyes of juvenile and 70 eyes of maturity onset diabetics by means of the esthesiometer developed by Draeger. We found a significant decrease in corneal sensitivity in both juvenile and maturity-onset diabetics with a positive correlation between the decrease of corneal sensitivity and duration of symptoms in juvenile diabetics. In addition, the decrease in corneal sensitivity was more marked in diabetics with insufficient blood sugar control. Only 43% of diabetics with fundal changes had a concomitant decrease in corneal sensitivity. Diabetic retinopathy therefore seems to precede a polyneuropathy demonstrable by measurements of corneal sensitivity.

Adult↗
PubMed1982

[Preliminary results with the Lincoff-Kreissig balloon buckle].

The authors used the unsecured balloon buckle of Lincoff and Kreissig in 15 cases during a six-month period (September 1981 to March 1982) at the Ist Eye Clinic in Vienna and the Eye Department in Salzburg. Cases were selected in which one large tear and a circumscribed detachment existed, as well as detachments with only one tear or a group of holes which did not exceed one hour in extent. After an observation period of between three and nine months the detachment was cured with the balloon buckle in 12 eyes, while in three eyes it failed; in two of them a cure was achieved by permanent buckle operation. In one eye the find result was MPP. This method seems particularly suited to cases where cryocoagulation or photocoagulation alone is too dangerous, but on the other hand a permanent buckle operation might cause muscle disturbances and irritating diplopia in eyes with usually good visual acuity before and after surgery. Further experience with the unsecured balloon buckle will show how far the indications for this method can be extended.

Female↗
PubMed1982

Corneal sensitivity during the menstrual cycle.

Corneal sensitivity was determined in 5 women with regular menstrual cycles by means of a new aesthesiometer developed by Dräger. Throughout one menstrual cycle we measured corneal touch thresholds (CTT) daily and did serial determinations of urinary luteinising hormone and pregnanediol levels. CTT rose in 4 women with proved ovulation in the days before or on the day of ovulation, while corneal sensitivity remained unchanged in one anovulatory subject. We observed no changes in CTT prior to menstruation. The decrease in corneal sensitivity might be related to the preovulatory oestrogen peak.

Adult↗
PubMed1981

[Corneal sensitivity after photocoagulation for diabetic retinopathy].

Corneal sensitivity was determined with the Draeger aesthesiometer in 39 patients with proliferative diabetic retinopathy who underwent treatment with a xenon photocoagulator or argon laser. In 29 patients measurements were performed before and after photocoagulation; in 10 patients the unaffected eye was used for comparison. Statistical evaluation showed a significant difference between the mean values for corneal touch threshold before and after argon laser coagulation. After xenon photocoagulation, corneal sensitivity was reduced in all patients (n = 7). It was shown that corneal sensitivity was significant lower after xenon photo coagulation than with argon laser coagulation.

Adult↗
PubMed1981

[Corneal sensitivity after retinal reattachment operation].

The corneal touch threshold (CTT) was determined in 35 eyes before and after retinal reattachment operations. In some cases the CTT of the unaffected eye was taken for comparison. The new aesthesiometer developed by Draeger in 1977 was used and measured CTT in the center of the cornea and in the 12, 3, 6, and 9 o'clock position 1 mm from the limbus. Thirty eyes (86%) showed a rise in CTT after retinal reattachment operations, irrespective of the method of anaesthesia used, and the decrease in corneal sensitivity was observed for up to a period of 5 years postoperatively. Loss of corneal sensitivity was more marked in operations with diathermy and scleral pocketing than in cases with cryopexy and plombage operations. Extremely high CTT values were observed in eyes that underwent encircling procedures, cryopexy, vitrectomy, and gas injection. There was a significantly higher decrease in corneal sensitivity after encircling procedures than after plombage operations.

Adolescent↗
PubMed1981

[Prophylactic treatment of retinal detachment].

The indications for and results of prophylactic treatment of retinal detachment during a period of five years are reported and compared with the results in the literature. Half of the cases (3 out of 6 eyes) which developed a retinal detachment had been horse-shoe tears combined with a vitreous hemorrhage. For this reason a small buckle operation is recommended in these cases, to prevent further traction. Lattice degeneration should rather be observed than treated, except in special cases: This includes eyes where the fellow eye had a detachment from a lattice degeneration, cases in which one eye is blind from an uncured detachment or has no useful visual acuity, and eyes whose fellow eye has giant tears. In aphakic eyes treatment of lattice degeneration is recommended, because the incidence of detachment from these areas is high, especially in young aphakic cases. In one aphakic eye which had been photocoagulated several times the formation of a preretinal membrane was observed.

Female↗
PubMed1981

[Corneal sensitivity in chronic open-angle glaucoma (author's transl)].

Corneal sensitivity was measured in 91 eyes suffering from chronic open-angle glaucoma using the electronic-optical hand esthesiometer after Draeger. It was found that the threshold value in eyes with glaucomatous cupping or atrophy of the optic nerve was significantly increased, in contrast to eyes with normal optic disks, but that there was no direct relationship between IOP at the time of measurement and the duration of the open-angle glaucoma. The reduced sensitivity was due to damage of the long ciliary nerves between the choroid and sclera. The authors' findings thus support the view that glaucomatous atrophy of the optic nerve is caused by primary pressure atrophy of the retina.

Adult↗
PubMed1981

Acute ocular hypotony. A rare complication of temporal arteritis.

Acute ocular hypotony is a serious, but rare complication of temporal arteritis. It occurs equally often in men and women, and appears mostly in patients older than 70 years. This complication may occur in one or in both eyes. In the literature 7 cases of temporal arteritis accompanied by ocular hypotony have been reported. Hypotony probably results from a restricted production of aqueous humor caused by involvement of the arteries supplying the ciliary body. A high-dose corticoid therapy may normalize completely the intraocular pressure, and a timely treatment may preserve a satisfactory vision, since an insufficient perfusion of the optic disc does not necessarily occur. Scalp necrosis and diplopia may appear at the same time, and are a sign of multiple involvement of the arterial vessels.

Aged↗