Search PubMed⌕ Search

Biomedical subjects

N Simon

Publications and source records attributed to N Simon.

At least 109 records · Page 6Linked to original sources
PubMed1983

[Long-term effects of plasma exchange in myasthenia. Results of a randomized study].

A randomized study was carried out in 14 myasthenia patients to compare the long-term effects of two therapeutic regimens. Group I patients received prednisone 1 mg/kg/24 h for one month, then in decreasing dosage; in case of failure at the end of the first month, cyclophosphamide 2 mg/kg/24 h was added to the prednisone treatment. Group II patients received the same treatment associated with 3 plasma exchanges over a 10-day period; these were continued, if required, at the rate of once a week. The minimum follow up was one year. The results (greater improvement in muscular strength and vital capacity) were better after one month in group I and thereafter similar in both groups. However, the mean daily dose of prednisone was higher in Group I. The number of exacerbations of myasthenia was greater in group II (11 versus 2 in group I over a 24-months period). The mean fall in anti-R Ach ab was about the same in both groups. This study confirms the rapid effectiveness of plasma exchanges and their value in severe myasthenia. The higher incidence of exacerbations in Group II was probably due to a rebound phenomenon and points to the need for combined immuno-suppressive treatment.

Adult↗
PubMed1983

The stressful impact of news of risk for premature heart disease.

Efforts at prevention of disease include case-finding of individuals at high risk and offering to these identified people an intervention to reduce their risk. Although the intention of intervention is to reduce risk, the impact of discovering that one is at high risk may also lead to intrusive ideas and feelings that characterize psychological stress response syndromes. The present study examined these issues with a sample of 1,447 men who were advised of their risk for coronary heart disease in the collaborative Multiple Risk Factor Intervention Trial. Comparisons over three yearly data collections between a usual care and special intervention group showed that the special intervention group reported a far greater level of coping and mastery efforts regarding their risk status. This was accompanied by a much smaller tendency to be bothered by intrusive thoughts, but amount of reported upset did not differ. Finally, a small group of men in both groups indicated continuing high levels of upset across the three years. Clinicians are advised to be watchful for these persons for whom mastery of the news appears to be difficult.

Adaptation, Psychological↗
PubMed1983

Involvement of sensory nerve endings in cold and heat urticaria.

The involvement of sensory nerve endings in acquired cold and heat urticaria was studied in 8 patients. After repeated topical application of capsaicin, the skin was tested for whealing with cold and heat stimuli. Capsaicin pretreatment prevented the urticarial responses for 4-7 days. Since capsaicin is known to induce selective impairment of the chemosensitive nerve endings, the results suggest that these nerve fibers may play an important role in acquired cold and heat urticaria. The possible mechanisms are discussed.

Adult↗
PubMed1983

Transfusion therapy for erythropoietic protoporphyria.

Five patients with erythropoietic protoporphyria, in whom beta-carotene treatment had proved unsuccessful, were treated on 5 or 6 occasions with washed, packed red blood cell transfusions. Following the transfusions, the photosensitivity and the protoporphyrin levels in the red blood cells decreased considerably. This treatment may be useful in reducing the high protoporphyrin level in patients with a rapidly deteriorating hepatic function.

Blood Transfusion↗
PubMed1983

A comparative study of the inhibitory effect of trypan blue on mouse erythrocyte and C3 binding receptors of peripheral blood mononuclear cells from healthy donors and patients suffering from chronic lymphocytic leukaemia.

Trypan blue has previously been shown to interact with the C3 receptor, but not with the Fc receptor. In the present work the effects of Trypan blue on mouse erythrocyte (ME) and C3 binding receptors of the peripheral blood mononuclear cells have been studied in healthy individuals and in patients with chronic lymphocytic leukemia (CLL). The resulting dose-response curves have been compared with each another. The results of statistical analysis indicate that there is no significant difference between the effects of trypan blue on the two receptors in healthy individuals. In contrast ME and C3 binding receptors differ significantly in trypan blue sensitivity in CLL patients. These data suggest that the two receptors are similar, or are situated on the cell membrane in such a way that the trypan blue bound to one of them inhibits the functioning of the other one too, but they are not the same. In the course of leukemic transformation, the trypan blue sensitivity of the ME binding receptor does not vary, whereas that of the C3 receptor is enhanced significantly.

Animals↗
PubMed1983

Relationship of mouse erythrocyte binding receptor on peripheral blood mononuclear cells to receptors for IgG Fc and C3.

When peripheral blood mononuclear cells separated at 4 degrees C were incubated at 37 degrees C, they shed their surface receptors. Total absorption of the released mouse erythrocyte binding receptors from the supernatant of the cell suspension with mouse erythrocytes did not lead to a change in the IgG Fc and C3 receptor content of the supernatant. On removal of the C3 or IgG Fc receptors, the quantity of mouse erythrocyte binding receptor remained unchanged. These observations indicate that the three receptors are mutually independent structures, or undergo dissociation in the course of the shedding.

Animals↗
PubMed1982

[Comparative immunologic studies in PUVA and SUP (selected ultraviolet phototherapy) treatments].

10 PUVA and 13 SUP-treated psoriatic patients were examined immunologically. The proportion of sheep and mouse erythrocyte rosette forming lymphocytes, the leucocyte migration inhibitory assay, the lymphocyte transformation test were carried out and the suppressor function of peripheral blood mononuclear cells was measured before and 48 hours after the clearing of lesions. The results observed before and after the treatment were compared to each other and to the values of healthy volunteers. No significant difference was observed between the results obtained before and after the treatment, meaning that the immune alterations, which have been observed by several authors immediately after PUVA therapy or UV light irradiation, were not detectable if the tests wer made 48 hours later than the last treatment. The significantly decreased suppressor function of peripheral blood mononuclear cells was not changed during the therapy either.

Cell Migration Inhibition↗
PubMed1982

Regulation of lymphokine production in peripheral blood mononuclear cell cultures.

An increase in the production of macrophage migration inhibitory factor, chemotactic factor for neutrophils, and skin reactive factor, was observed in lymphocyte cultures if the cells were allowed to age in culture for 24 h. The increased lymphokine production was reduced by adding concanavalin A-stimulated and mitomycin C-treated suppressor cells. It is suggested that the lymphokine production could be regulated by suppressive mononuclear cells.

Cells, Cultured↗
PubMed1982

The role of possible membrane damage in porphyria cutanea tarda: a spin label study of rat liver cell membranes.

Two groups of rats were made porphyric by treatment for a shorter or a longer time with hexachlorobenzene (HCB); a third group was subjected to chronic treatment with ethanol; the fourth group comprised untreated, control animals. Suspensions were prepared of hepatocytes isolated from the livers of the animals in the individual groups, and in these systems the cell membranes were studied by spin labeling. In all three chronically treated groups, the order parameter calculated from the ESR spectra was significantly lower than that of the control group. The order parameters ofr the first three treated groups, however, did not differ significantly from one another. If either HCB or ethanol was incorporated into the isolated hepatocytes of the healthy control animals, the fluidity of the hepatocyte membranes increased. The order parameter decrease (compared to the control) for the hepatocyte membranes of the animals treated chronically with HCB or ethanol can be ascribed to the direct membrane-fluidizing effect of HCB or ethanol, and also to the altered lipid metabolism. With regard to the difference in the mechanisms of action of HCB and ethanol, on the basis of the experimentally proved membrane-damaging effect of the porphyrinogenic HCB it is probable that, besides other factors, the membrane damage may play an important role in the pathogenesis of porphyria cutanea tarda.

Animals↗
PubMed1981

[Testing a cellulose diacetate membrane for plasma exchange (author's transl)].

A cellulose diacetate membrane was tested in 60 plasma exchanges (PE) carried out in 16 patients. Access to the vascular compartment was obtained through one single puncture by inserting a catheter into the femoral vein, the blood circuit being provided with an alternating clamp. The exchange of 2 plasma volumes (72.3 +/- 16 ml/kg) reduced IgG, IgA and IgM concentrations to 30.9 +/- 12.1%, 31.6 +/- 14.5% and 28.3 %/- 15.0% respectively of pre-PE concentrations. Similarly, the C3 and C4 complement fractions and factor B were reduced to 32 +/- 12%, 33 +/- 15% and 36 +/- 16% respectively of pre-PE values. The membrane was used several times in 7 patients; its performance remained the same after 3 consecutive uses. In view of its effectiveness and ease of application, the cellulose diacetate membrane appears to be particularly suitable for plasma exchanges in intensive care units.

Cellulose↗
PubMed1981

Study of DNA repair on a xeroderma pigmentosum patient and his heterozygotic parents.

Unscheduled DNA synthesis, photoreplication repair capacity, and photoreactivating enzyme levels were examined in cells of individuals of a family with one case of XP and otherwise clinically normal parents. The patient's parents were first cousins. The activity of three paths of DNA repair was depressed in the XP cells. The clinically normal parents showed normal levels of unscheduled DNA synthesis as well as postreplication repair, however their photoreactivating enzyme level was as low as 30% of normal levels.

DNA Repair↗