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Biomedical subjects

R Rask

Publications and source records attributed to R Rask.

8 recordsLinked to original sources
PubMed1996

Epithelial healing in the second eye after corneal abrasion.

Corneal epithelial healing velocity was determined in patients admitted to excimer laser photo refractive keratectomy, by daily video planimetry of the denuded area until complete healing. The epithelial healing process was followed in fellow eyes with regard to intervals between surgery of the two eyes of 1 to 10 weeks. In cases where the fellow eye was treated at one week after the first eye, the lesions healed significantly faster in the second eye as compared to patients with longer delay between the two operations.

Adult↗
PubMed1995

Precision of ultrasonic estimates of choroidal melanoma regression.

BACKGROUND: Important prognostic information may be gained from knowledge of the volume and, over time, the change in volume of intraocular tumors such as choroidal melanomas. METHODS: The precision and time consumption of three different ultrasonographic methods were evaluated. Seven choroidal melanomas were analysed after placement of a ruthenium plaque and again after tumor regression had occurred. Perpendicular ultrasound B-scans were printed and analysed by overlay grid counting or outline tracing of tumor structures to calculate the volume. These two methods, using only two perpendicular scans, were compared with a micro-computer-controlled ultrasonographic three-dimensional rotation scanning system, where each tumor was manually outlined in 20 revolving scan planes RESULTS: The three-dimensional volume scanning method was the most precise, but also the most demanding in hardware and time consumption. CONCLUSION: Increased precision and less observer-dependent estimation of shrinkage rate after radiotherapy is available at the cost of sophisticated equipment.

Adult↗
PubMed1995

Video controlled M-mode biometry.

To increase the accuracy of intraocular lens power calculation, an interface between an ultrasonic A-scanning device and a personal computer was created, allowing for an on-line interpretation of the ultrasonogram in an M-mode fashion. On the same computer display, a video recording of the movements of the transducer probe relative to the eye was inserted to obtain simultaneous information on the external alignment of the transducer probe. The precision of the experimental set-up in the measurement of intraocular distances was compared with conventional A-scanning procedures run in automatic mode. The video controlled M-mode biometry was found easy to operate and to result in reproducible axial length determination: The median value of the standard deviation was found to be below 0.04 mm as compared to a value of about 0.10 mm with conventional equipment. We concluded that video controlled M-mode biometry has great potential in the endeavour to increase the accuracy of intraocular lens calculation.

Anterior Chamber↗
PubMed1995

Healing velocity of corneal epithelium evaluated by computer. The effect of topical steroid.

To objective determine the area of corneal abrasion, a video camera was connected to a slit-lamp. The videosignal was digitized and analyzed by a computer program. The maximal horizontal and vertical diameters were measured as well as the total abraded area. The algorithms of calculating healing velocity of corneal epithelium are discussed, and this system was tested on patients treated for myopia with a 193 nm ArF excimer laser. It was shown that topical steroid application did not impair corneal epithelial healing velocity.

Administration, Topical↗
PubMed1989

Enhanced binding of immune complexes processed by erythrocyte CR1 (CD 35) receptors to purified CR2 (CD 21) receptors from tonsillar mononuclear cells.

The binding of immune complexes (IC) opsonized by serum complement (C) and IC processed by CR1 (CD 35) receptors on human erythrocytes (E) to purified CR2 (CD 21) receptors was compared. Soluble CR2 was prepared from tonsillar mononuclear cells and purified by antibody affinity chromatography. Solid phase CR2 as well as CR2 subjected to PAGE and blotted onto nitro-cellulose membranes bound 125I-labelled BSA anti-BSA IC which had been opsonized by C and processed by CR1 up to ten times more efficiently than IC reacted with serum only. Radiolabelled monomeric C3d also bound to solid phase CR2. The binding of IC to purified and solid phase bound CR2 could be inhibited by anti-CR2 antibodies or by preincubation of the IC with polyclonal antibodies reacting with C3d or C3b/iC3b. Thus, both C3dg and iC3b appeared to mediate binding of IC to CR2. Preincubation of solid phase CR2 with purified monomeric C3d did not inhibit the subsequent binding of E-CR1 processed IC. The data indicate that E-CR1 have an important role in generating IC which bind effectively to CR2 receptors on B lymphocytes.

Animals↗
PubMed1988

Quantification of C3dg/Epstein-Barr virus receptors on human B cells and B cell lines.

The expression of C3dg/Epstein-Barr virus receptors (CR2) on human peripheral blood and tonsillar B lymphocytes and Raji cells was quantified by measuring binding of unlabeled monoclonal anti-CR2 antibody (OKB7 and HB-5) in an indirect immunoenzymatic assay. Scatchard analysis of saturation binding curves revealed that Raji cells on the average express about 22,000 and 17,000 binding sites, with mean affinity constants of 9.9 X 10(10) and 8.7 X 10(10) M-1 for OKB7 and HB-5, respectively. Tonsillar mononuclear cells (TMC) expressed 16,700 and 17,600 binding sites for OKB7 and HB-5, respectively, with a significantly lower affinity constant for HB-5 (3.2 X 10(10) M-1) than for OKB7 (9.0 X 10(10) M-1). On the average 34% of E- peripheral blood mononuclear cells (PBMC) from healthy donors and 49% of TMC expressed the CR2 antigen. When correcting for the fraction of CR2-positive cells, the mean CR2 density was 12,600 on E- PBMC (n = 10) and 34,000 on TMC (n = 4).

Animals↗
PubMed1988

Complement C3d,g/Epstein-Barr virus receptor density on human B-lymphocytes estimated by immunoenzymatic assay and immunocytochemistry.

The density of the C3d,g/Epstein-Barr virus receptor (CR2) on human mononuclear cells (MNC) isolated from CPD stabilized blood, was determined by comparing the concentration of CR2 antigen in extracts from Raji cells, with a known receptor density, with extracts of MNC. The concentration of CR2 was determined by a sandwich ELISA using two mutually non-inhibiting monoclonal anti CR2 antibodies (HB5 and OKB7). The percentage of CR2+ MNC was determined by an immunocytochemical staining method. Analysis of MNC from 20 healthy donors, revealed that the density of CR2 molecules varied from 3,600-7,700 on CR2+ cells, and that the percentage of CR2+ MNC had a mean of 13%.

B-Lymphocytes↗