Role of Alkali Cations in DNA-Thioflavin T Interaction.

This study investigates the role of alkali cations in modulating the interaction between deoxyribonucleic acid (DNA) and Thioflavin T (ThT) in dilute and condensed phases. The emission characteristics of ThT were analyzed in the presence of double-stranded DNA and G-quadruplex structures with a focus on the effects of four cations: sodium, potassium, calcium, and magnesium. The ThT emission in double-stranded DNA was influenced by direct DNA binding and steric hindrance within the hydration shell of DNA, which was modulated by the presence of alkali cations. Lasing spectroscopy experiments further highlighted ThT sensitivity to the spatial arrangement of water molecules in the DNA hydration shell. Lasing was exclusively observed in the presence of Mg2+ in the G-quadruplex structure, suggesting that the parallel propeller configuration of G4 provides an optimal environment for ThT light amplification. This study highlights the critical role of cations in DNA-dye interactions and reaffirms the significance of ThT in biophysical studies.

Cavity Lasing Characteristics of Thioflavin T and Thioflavin X in Different Solvents and Their Interaction with DNA for the Controlled Reduction of a Light Amplification Threshold in Solid-State Biofilms.

The lasing characteristics of Thioflavin T (ThT) and Thioflavin X (ThX) dyes were investigated in solvents with increasing viscosity: water, ethanol, butanol, ethylene glycol, and glycerol and three forms of DNA (double-helix natural, fragmented, and aggregated). The results identified that lasing thresholds and photostability depend on three critical factors: the solvation shell surrounding dye molecules, the organization of their dipole moments, which is driven by the DNA structure, and the molecules diffusion coefficient in the excitation focal spot. The research highlights that dye doped to DNA accumulated in binding sites fosters long-range dye orientation, facilitating a marked reduction of lasing thresholds in the liquid phase as well as amplified spontaneous emission (ASE) thresholds in the solid state. Leveraging insights from lasing characteristics obtained in liquid, ASE in the solid state was optimized in a controlled way by changing the parameters influencing the DNA structure, i.e., magnesium salt addition, heating, and sonication. The modifications led to a large decrease in the ASE thresholds in the dye-doped DNA films. It was shown that the examination of lasing in cavities can be useful for preparing optical materials with improved architectures and functionalities for solid-state lasers.

Identification of Thioflavin T Binding Modes to DNA: A Structure-Specific Molecular Probe for Lasing Applications.

The binding mechanism of thioflavin T (ThT) to DNA was studied using polarized light spectroscopy and fluorescence-based techniques in solutions and in solid films. Linear dichroism measurements showed that ThT binds to DNA duplex by intercalation. Time-resolved fluorescence studies revealed a second binding mode which is the external binding to the DNA phosphate groups. Both binding modes represent the nonspecific type of interactions. The studies were complemented with the analysis of short oligonucleotides having DNA cavities. The results indicate that the interplay between three binding modes-intercalation, external binding, and binding inside DNA cavities-determines the effective fluorescence quantum yield of the dye in the DNA structures. External binding was found to be responsible for fluorescence quenching because of energy transfer between intercalated and externally bound molecules. Finally, amplified spontaneous emission (ASE) was successfully generated in the ThT-stained films and used for detecting different DNA structures. ASE measurements show that ThT-stained DNA structures can be used for designing bioderived microlasers.

[Use of soft contact lenses in the Riley-Day syndrome in a small child]. / Zastosowanie miekkich soczewek kontaktowych w zespole Riley-Day u malego dziecka.

We present the observation of a boy treated in our Ophthalmological Department in Wroclaw from the age of 6 months up to 6 years for the serious keratitis with ulceration. We diagnosed Riley-Day syndrome with regard to many associated pathological features. The efficacy of the local treatment improved after application of soft contact lenses.

[Refractive surgery in myopia. I. Radial keratotomy]. / Zabiegi refrakcyjne w krótkowzrocznosci. I. Keratotomia radialna.

It is stressed that in myopia one performs 2 kinds of operation: therapeutical and for a change in refraction. Not only surgical methods but also the aim of operation are basically different. The author present the foundation, the development of the method, the up-to-date results of operation and complications connected with the radial keratotomy which is not therapeutical but refractive operation. Especially precisely are presented the qualification criteria for the surgery which are basing mainly on a--conceived on a large scale--American PERK study.

[Macular pucker after surgery for retinal detachment]. / Pomarszczenie plamki po operacjach odwarstwienia siatkówki.

Twenty four patients with a preoperative macular detachment were subjected to a 6 months observation. The evaluation of the macular function was carried out on the basis of following examinations: the visual acuity, central visual field, dazzling test, Amsler's test and Heidinger phenomenon. The morphology of the changes was evaluated ophthalmoscopically and biomicroscopically by means of Goldmann's lens and the slit-lamp. The macular pucker appeared in 25 p.c. of examined patients, in 16.7 p.c. of cases with non-translucent and in 8.7 p.c. with translucent membranes. In all cases of macular pucker after retinal detachment surgery the macular function remained severely handicapped.

[Detachment of the choroid after cataract extraction]. / Odlqczenie naczyniówki po operacji zacmy.

Injections of air into the anterior chamber were applied by the authors in choroidal detachment and flat anterior chamber after 22 cataract extractions and 4 fistulizing operations in glaucoma (together 26 cases) after an ineffective conservative treatment. The deepening of the anterior chamber and reapposition of the choroid was achieved in all the cases. Special attention in applying this method was called to the deepening of the anterior chamber and to supply a considerable amount of air into the eye, so as to raise the intraocular pressure up to the normal values or even more. The air remained in the eye even for 7 days. In 12 cases there was a need to inject the air a second time because of an insufficient reapposition of the choroid after the resorption of the air finished or because of the recurrence of the detachment.

[Postoperative complications with the use of implants for treatment of retinal detachment]. / Powiklania operacji z uzyciem wszczepów w leczeniu odwarstwien siatkówki.

Complications of the retinal detachment surgery with the use of episcleral and intrascleral implants are presented. The authors are using biological materials (fascia lata, dura mater) as well as alloplastic materials (Lincoff's sponge). Among the postoperative complications following were seen: protracted reactions from the side of the ocular adnexa, intraocular haemorrhages, intravitreal exudates. The most severe from the observed complications was the atrophy of the sclera at the spot of implantation of the silicon sponge.

[Circulating immune complexes in children with uveitis]. / Krazace kompleksy immunologiczne u dzieci z zapaleniem blony naczyniowej.

The occurrence of circulating immunological complexes was investigated in 25 children with uveitis (11 with an anterior and 14 with posterior uveitis). The presence of complexes was found in 15 children, among them in 6 with anterior and 9 with posterior uveitis. Besides the diseased children showed a significant lowering of the percentage of the T lymphocytes by simultaneous increased percentage of B lymphocytes and also a raised concentration of the serum immunoglobulins of M, A and G class.

[Selected immunologic parameters in uveitis]. / Wybrane parametry immunologiczne w zapaleniu blony naczyniowej.

The behaviour of selected immunological parameters was checked in 38 patients with uveitis. The presence of immunological complexes was found in 23 patients and in 9 a positive Waaler-Rose's reaction. All patients showed a considerable fall in the percentage of the T lymphocytes with an increase of the B lymphocytes without markers as well as an increased concentration of the serum immunoglobulins of the M, A and G class.

[Studies of the effect of environmental factors on the visual system (based on the examination of workers at a precision instrument factory)]. / Wplyw czynników srodowiskowykh na stan ukLadu wzrokowego (na podstawie badan przeprowadzonych u pracowników zakladów wytwórczych aparatury precyzyjnej.

The studies involved 254 workers of a Precise Devices Plant. The impact of working conditions (chemical pollutants and lighting) on the sight organ was examined. In the test group a considerable percentage (29.5%) of chronic conjunctivitis was found. The disease results from a long-lasting exposure to dusts of various origin, as well as from improper lighting. The posttraumatic and post-inflammatory impairments of the sight organ, diagnosed by ophthalmological examinations, were not of occupational origin.

Selected immunological parameters in patients suffering from uveitis subjected to different treatment.

Selected immunological parameters were studied in 70 subjects suffering from uveitis. The patients were treated with steroids, non steroid antiinflammatory drugs, and typhoid vaccine. After termination of treatment the following observations were noted: partial disappearance of immune complexes from circulation, increase of T lymphocytes and decrease of B lymphocytes percentage, decrease of IgG, IgM and IgA serum concentration, normalization of acute inflammation parameters (reduction of: ESR, leukocyte count, total protein and seromucoid concentrations; increase of albumin concentration).

Circulating immune complexes in uveitis.

The occurrence of circulating immune complexes was studied in 28 patients suffering from uveitis. The presence of complexes was found in 18 patients including 6 out of 10 patients with iridocyclitis and in 12 out of 18 patients with chronic total uveitis.