PubMed Health⌕ Search

Biomedical subjects

R Elias

Publications and source records attributed to R Elias.

At least 19 recordsLinked to original sources
PubMed1994

Effects of alpha-hederin, a saponin extracted from Hedera helix, on cells cultured in vitro.

In this work, we have analysed the effects of alpha-hederin, a monodesmosidic triterpenoid saponin isolated from Hedera helix, on mouse B16 melanoma cells and non-cancer mouse 3T3 fibroblasts cultured in vitro. Our results indicate that, in a serum-free medium, alpha-hederin is cytotoxic and inhibits proliferation in both cell lines at rather low concentrations (< 5 micrograms/ml) after only 8 hours of treatment. Its cytotoxicity decreases in the presence of serum in which BSA seems to be able to bind the saponin. alpha-Hederin also induces vacuolization of the cytoplasm and membrane alterations leading to cell death.

3T3 Cells↗
PubMed1994

In vitro antifungal activity of triterpenoid saponins.

The antifungal activity of triterpenoid saponins, with hederagenin or oleanolic acid as aglycone, was investigated in vitro by the agar dilution method. Monodesmosidic hederagenin derivatives were shown to exhibit a broad spectrum of activity against yeast as well as dermatophyte species. alpha-Hederin was the most active compound, and Candida glabrata was the most susceptible strain. The structure-activity relationships are discussed.

Antifungal Agents↗
PubMed1991

A 27-year experience with splenectomy for Gaucher's disease.

Gaucher's disease is an inherited metabolic disorder caused by the defective activity of acid beta-glucosidase and the resultant accumulation of glucosyl ceramide-laden macrophages in the liver, bone, and spleen. Splenectomy is the preferred treatment for patients with Gaucher's disease who develop massive splenomegaly with accompanying hypersplenism and/or mechanical pressure symptoms. The charts of 48 patients with Gaucher's disease undergoing splenectomy at our institution between January 1963 and December 1989 were analyzed to determine the short- and long-term results of this procedure. Thirty-five (73%) patients had total splenectomy, whereas 13 (27%) patients had partial splenectomy. There was one postoperative death (after total splenectomy), and 13 patients (27%) had postoperative complications. Eleven patients (23%) presented with accelerated bone disease after total splenectomy (mean follow-up: 96 months). No patients having partial splenectomy (mean follow-up: 25 months) developed progressive bone disease. Eight patients have died since surgery. All four deaths due to malignant disease occurred in patients after total splenectomy. The results of this largest-ever reported series of splenectomy for Gaucher's disease confirm that while either total or partial splenectomy can be performed with minimal morbidity and mortality, total splenectomy is accompanied by more aggressive bone disease and a predisposition to malignancy. Prospective, randomized trials are needed to substantiate whether partial splenectomy is indeed the treatment of choice for splenomegaly associated with Gaucher's disease.

Adult↗
PubMed1991

Saponins of the ivy plant, Hedera helix, and their leishmanicidic activity.

Antileishmanial activity is reported for the first time for saponins of ivy, Hedera helix L., in vitro on promastigote and amastigote forms of Leishmania infantum and Leishmania tropica. The compounds tested were an extract containing 60% of saponic complex (CS 60), the bidesmosides hederasaponin B, C, and D (saponin K10), their corresponding monodesmosides alpha-, beta-, and delta-hederin, and hederagenin. CS 60 and bidesmosides have shown no effect. Monodesmosides were found to be as effective on promastigote forms as the reference compound (pentamidine). Against amastigote forms only hederagenin exhibited a significant activity which was equivalent to that of the reference compound (N-methylglucamine antimonate).

Animals↗
PubMed1990

Acute inhibition of DNA synthesis in hamster buccal pouch epithelium exposed to indirect acting carcinogens.

Inhibition of DNA synthesis was observed and quantitated in hamster buccal pouch epithelium exposed in vivo and in vitro to indirect acting carcinogens. Topical application of a 0.5% solution of the potent hamster buccal pouch carcinogen 7,12-dimethylbenz[a]-anthracene (DMBA) acutely inhibited epithelial DNA synthesis by 40-65%, as indicated by a decrease in [3H]thymidine incorporation over a period of 24 h. When applied twice at a concentration of 2%, N-methyl-N-benzylnitrosamine (MBN), another potent buccal pouch carcinogen, inhibited epithelial DNA synthesis by 76% within a period of 4 h. A similar acute inhibitory effect on DNA synthesis was observed when explants of buccal pouch mucosa, exhibiting continuous cell replication, were exposed in vitro in the presence of MBN or DMBA for periods up to 12 and 24 h, respectively. The inhibitory effect of DMBA was greater than that of other polycyclic aromatic hydrocarbons of lesser carcinogenic potency in this tissue. This study demonstrates that the metabolic activation of indirect acting carcinogens leading to acute cytotoxicity and inhibition of DNA synthesis occurs rapidly in hamster buccal pouch mucosa exposed to these agents in vitro as well as in vivo. The experimental imposition of an acute inhibitory pressure, applied as demonstrated in this report, may enable the detection of precancerous cells which have acquired the property of resistance to this cytotoxic effect in the course of carcinogenesis. In principle, the in vitro approach, coupled with autoradiography, may be useful in identifying microscopic foci of resistant preneoplastic cells in samples of human oral mucosa. 24R01 34160

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1990

Antimutagenic activity of some saponins isolated from Calendula officinalis L., C. arvensis L. and Hedera helix L.

Thirteen saponins were isolated and identified from Calendula officinalis, C. arvensis and Hedera helix. Mutagenic and antimutagenic activities of these products were investigated using a modified liquid incubation technique of the Salmonella/microsomal assay. The Salmonella tester strain TA98 +/- S9 mix was used. Screening of the antimutagenic activity was performed with a known promutagen: benzo-[a]pyrene (BaP) and a mutagenic urine concentrate from a smoker (SU). Antimutagenic activities were also compared with the activity of chlorophyllin. All the saponins were found to be non-toxic and non-mutagenic for doses of 400 micrograms. Chlorophyllin inhibited the mutagenic activities of BaP (1 microgram) and SU (5 microliters) in a dose-dependent manner. The four saponins from C. arvensis and the three saponins from H. helix showed antimutagenic activity against BaP (1 microgram) and SU (5 microliters) with a dose-response relationship. The possible mechanism of the antimutagenic activity of saponins is discussed.

Animals↗
PubMed1987

The regulation of lymphatic pumping.

An important functional property of lymphatic vessels is their ability to pump fluid. To quantitate this activity in vivo, sheep mesenteric lymphatic segments were isolated from all lymph input and provided with lymph plasma or saline from a reservoir. Lymphatic pumping was controlled by transmural pressure with increases in pressure resulting in elevated fluid pumping followed by reductions in flow at high intraluminal pressures. With lymph input to the vessels denied, but with blood and nerve supply left intact, the pumping activity could be altered with systemic physiological perturbations including a major blood loss and the intravenous infusion of endotoxin. In each case, it was clear that the modulation of lymphatic pumping resulted from the direct effects of the test procedure on the 'lymph pump' and not from effects on vascular parameters or lymph formation.

Animals↗
PubMed1986

Quantitative approaches to the study of lymphatic contractile activity in vitro and in vivo: potential role of this dynamic 'lymph pump' in the re-expansion of the vascular space following hemorrhage.

Few investigators have considered a dynamic role for the lymphatic vessel in regulating the movement of fluid and protein from the interstitium back to the bloodstream. This view is based on the assumption that lymphatics are passive conduits and that hydrostatic pressure gradients and external compression forces acting on the vessels are primarily responsible for the movement of lymph. However, it is becoming increasingly evident that the intrinsic contractile capabilities of lymphatic vessels provide a major part of the propulsive force. Lymphatics have noradrenergic innervation and respond to a variety of humoral factors and inflammatory mediators suggesting that the pumping activity is centrally regulated and in addition, may respond to local factors. In this article, we will discuss what is known of the regulation of this 'lymph pump'. Techniques that permit analysis of contractile activity and fluid pumping in vitro and in vivo will be reviewed. Of particular interest is a sheep model that allows the quantitation of pumping activity in vivo without the complication of variable lymph inputs. While there is little information available at this time concerning the potential role of the 'lymph pump' in pathophysiological states, some preliminary experiments from our own laboratory suggest that an independently regulated 'lymph pump' may play an important role in hemorrhagic shock.

Animals↗
PubMed1980

[Job tasks and occupational diseases in data processing].

The industrial organisational model of repetitive work, a consequence of Taylor type rationalization, is encountered in datra computerized processing sectors, especially for data input tasks, with the same effects: pressure of time, monotony, insatisfying work. a group of data collecting female operators was investigated and compared to a group of female operations whose activities included computer dialoguing, a more complex task. Recordings of eye movements for the analysis of perceptive and cognitive aspects of the task, as well as questionnaire concerning the effect of factors such as stress in their lives, and the possible presence of psychosmatic and nervous symptoms, were used. The resulting data showed the task content impact upon the life at work and its more harmful effect on the mental and bodily comfort of data input operators.

Adult↗