Monocyte activation drives preservation of membrane thiols by promoting release of oxidised membrane moieties via extracellular vesicles

The redox state of cellular exofacial molecules is reflected by the amount of available thiols. Furthermore, surface thiols can be considered as indicators of immune cell activation. One group of thiol containing proteins, peroxiredoxins, in particular, have been associated with inflammation. In this study, we assessed surface thiols of the U937 and Thp1 monocyte cell lines and primary monocytes in vitro upon inflammatory stimulation by irreversibly labelling the cells with a fluorescent derivative of maleimide. We also investigated exofacial thiols on circulating blood mononuclear cells in patients with rheumatoid arthritis and healthy controls. When analysing extracellular vesicles, we combined thiol labelling with the use of antibodies to specific CD markers to exclude extracellular vesicle mimicking signals from thiol containing protein aggregates. Furthermore, differential detergent lysis was applied to confirm the vesicular nature of the detected extracellular events in blood plasma. We found an increase in exofacial thiols on monocytes upon in vitro stimulation by LPS or TNF, both in primary monocytes and monocytic cell lines (p<0.0005). At the same time, newly released extracellular vesicles showed a decrease in their exofacial thiols compared with those from unstimulated cells (p<0.05). We also found a significant elevation of surface thiols on circulating monocytes in rheumatoid arthritis patients (p<0.05) and newly released extracellular vesicles of isolated CD14⁺ cells from rheumatoid arthritis patients had decreased thiol levels compared with healthy subjects (p<0.01). Exofacial peroxiredoxin 1 was demonstrated on the surface of primary and cultured monocytes, and the number of peroxiredoxin 1 positive extracellular vesicles was increased in rheumatoid arthritis blood plasma (p<0.05). Furthermore, an overoxidised form of peroxiredoxin was detected in extracellular vesicle-enriched preparations from blood plasma. Our data show that cell surface thiols play a protective role and reflect oxidative stress resistance state in activated immune cells. Furthermore, they support a role of extracellular vesicles in the redox regulation of human monocytes, possibly representing an antioxidant mechanism.

[Experience with partial removable dentures anchored by the Vigano attachment]

In 1993 the Vigano attachment appeared in Hungarian commercial turnover. On the basis of 20 cases observed during one year it can be stated, that the use is simple for dental technicians, the fitting effect is good, requires small place, insertion and removal is easy for elderly and handicapped patients; it is aesthetically satisfying and the design ensures minimum likelihood of repairs.

[Anchoring of partial dentures using OT-CAP precision attachments]

The authors have examined a precision attachment recently invented in Hungary. They are reporting about the experience gained during clinical examination of dentures made in different classes on the basis of the Fábián and Fejérdy classification of partial edentulousness.

[Postoperative lymph node scintigraphy in patients with malignant melanoma]

Completeness of regional lymph node dissection was controlled in 23 patients with melanoma malignum. For that purpose 3--6 weeks after block-dissection lymph node scintigraphy was performed, by administration of intercostal and interdigital radiopharmacutical. Blockdissection was considered as complete, when neither after intercostal, nor after interdigital administration, any lymph nodes were delineated. On the basis of investigations until now, postoperative lymph node scintigraphy proves to be suitable, held to be a non-invasive method for controlling completeness of blockdissection.

Bone-scintigraphic examinations in patients treated with retinoids: a prospective study

Possible early side-effects of retinoid treatment on bones were studied with the aid of bone-scintigraphy. Isotretinoin treatment (1.0 mg/kg daily for 4 months) was given to 18 patients with acne. Fifteen patients with psoriasis received etretinate treatment (0.7-1.0 mg/kg/day) for 4 months. In the group treated with isotretinoin, pathological uptake of radiolabel was found in three cases, while in the group treated with etretinate, no bone changes attributable to treatment were found. During isotretinoin treatment, a decrease in growth-plate activity was observed. Bone-scintigraphy is considered to be a suitable method for early screening for bone changes occurring in retinoid treatment.

[Scintigraphic studies of the lymph nodes in patients with melanoma following lymph node excision]

We report on 20 patients suffering from malignant melanoma, who had undergone regional lymph node dissection. In order to make certain that all the lymph nodes had been completely removed, we performed lymphoscintigraphy 3 to 6 weeks after block dissection with the help of a radiopharmacon intercostally or interdigitally applied. We judged the removal to be complete, if neither intercostal nor interdigital application led to any evidence of regional lymph nodes. On the basis of our experiences so far, we consider postoperative lymphoscintigraphy a suitable non-invasive method to check the completeness of block dissection.

Spermatological investigations in patients treated with etretinate and isotretinoin

Possible side effects of the retinoids etretinate and isotretinoin on the germinal epithelium were examined. 15 men received etretinate and 13 isotretinoin. After 16 weeks of treatment at therapeutic doses, no changes were observed in fundamental spermatological parameters. On the basis of examinations and data in the literature, we hold the opinion that retinoid treatment is to be considered safe from the andrological viewpoint.