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Biomedical subjects

M Pinkas

Publications and source records attributed to M Pinkas.

At least 19 recordsLinked to original sources
PubMed1998

Antimicrobial activity of aerial parts of Drosera peltata Smith on oral bacteria.

The antimicrobial activity of extracts of aerial parts of Drosera peltata Smith against oral bacteria was investigated using agar diffusion and dilution micromethods. The chloroformic extract, active against all the bacteria tested, showed the most significant antimicrobial properties. Plumbagin, isolated from the extract, is the active principle. Results obtained suggest that Drosera peltata extract could be used in the treatment of oral infectious diseases like dental caries and periodontitis.

Anti-Bacterial Agents↗
PubMed1997

Antioxidant activities of polyphenolic extracts from flowers, in vitro callus and cell suspension cultures of Crataegus monogyna.

Numerous plants synthesize among their secondary metabolites phenolic compounds which possess antioxidant effects. The aim of the present work was to assay the antioxidant activities of phenolics from Crataegus monogyna Jacq. flowers and in vitro tissue culture (calli and cell suspensions) extracts. In the case of tissue culture extracts, the phenolic production is studied at three different stages of one subculture period (initial growth period, increasing and maximal phenolic synthesis phases). Attention was paid to the main categories: flavonoids and proanthocyanidins, and to the principal individual components. Total phenolic amounts decrease in the order: fresh flowers > cell suspension cultures > callus cultures. The antioxidant activities of these different extracts against H2O2 and HOCl, have been determined in vitro. All the extracts are efficient and the scavenging capacity is clearly related to the total phenol content. The scavenging effects of the cell suspension extracts are similar to those of the flowers. Among individual compounds, the flavanol-type derivatives, specially the proanthocyanidin B2, are more efficient. Thus, in vitro plant tissues could be an interesting source of bioactive molecules.

Anthocyanins↗
PubMed1996

Oxygen species scavenging activity of phenolic extracts from hawthorn fresh plant organs and pharmaceutical preparations.

Different extracts of fresh vegetative and reproductive organs from Crataegus monogyna harvested during a whole season and from some pharmaceutical hawthorn preparations exhibit in vitro antioxidant activities using three different models of oxygen reactive species generation (superoxide anion, hydrogen peroxide and hypochlorous acid). All the tested samples show low IC50 values, the most efficient being fresh young leaves, fresh floral buds and pharmaceutical dried flowers. The activities seem to be especially bound to the total phenolic proanthocyanidin and flavonoid contents.

Anthocyanins↗
PubMed1994

Activity of thymol, carvacrol, cinnamaldehyde and eugenol on oral bacteria.

The antimicrobial activity of thymol, carvacrol, cinnamaldehyde and eugenol alone or combined was tested by micromethods on eight oral bacteria. The compounds showed an inhibitory activity on seven microorganisms and a synergistic effect was observed with certain combinations. The four compounds can be used alone or combined, as eugenol and thymol, eugenol and carvacrol, thymol and carvacrol, during the treatment of oral infectious diseases.

Acrolein↗
PubMed1994

Antioxidant activities of Crataegus monogyna extracts.

Interesting antioxidant activities of extracts from different vegetative and reproductive organs of Crataegus monogyna harvested at different stages of growth have been determined by the malondialdehyde-thiobarbituric acid (MDA) test on hepatic microsomal preparations and compared to the contents in total phenolics, proanthocyanidins, catechins, flavonoids, and phenolic acids. The best correlations were established with total phenols while activities in leaves seem to be influenced by flavonoids and in flowers and fruits by proanthocyanidins and catechins.

Animals↗
PubMed1994

Activity of anthraquinonic and naphthoquinonic compounds on oral bacteria.

The activity of anthraquinonic compounds and naphthoquinones was tested by micromethods against oral bacteria. The more significant results were obtained with naphthoquinones. Plumbagin, juglone and lawsone possess a wide spectrum of activity. The lowest MIC values were observed with plumbagin and the combination of juglone and lawsone results in a synergism against cariogenic bacteria. Among the eight anthraquinonic compounds investigated only rhein showed significant antimicrobial properties. Results obtained could suggest the use of rhein and plumbagin alone or juglone and lawsone combined for treatment of oral infectious diseases.

Anthraquinones↗
PubMed1993

[Antibacterial activity of thymol, carvacrol and cinnamaldehyde alone or in combination].

The antimicrobial activity of thymol, carvacrol and cinnamaldehyde was tested by several methods on bacteria involved in upper respiratory tract infections. Their combinations were investigated too. The broad spectrum of activity and the synergistic effect observed with some combinations (specially thymol and carvacrol) could allowed the use of the three compounds alone or, like thymol an carvacrol, combined during the treatment of respiratory infections.

Acrolein↗
PubMed1992

Procyanidin Production by Fagopyrum esculentum Callus Culture.

FAGOPYRUM ESCULENTUM CALLUS cultures grown on B5 medium synthesize procyanidins B2 (0.6-1.8 mg/g dry wt) and B2-3'- O-gallate (3.5-6.0 mg/g dry wt). Sucrose is a better source than other carbohydrates and moderate concentrations (3-4%) stimulate both growth and procyanidin synthesis. While darkness was not a limiting factor, light induced faster growth and increased procyanidin contents. Treatment with gallic acid strongly stimulated the procyanidin B2-3'- O-gallate production, but drastically inhibited growth, leading to a two-step-culture experiment combining convenient growth and increased galloylated dimer synthesis (up to 45 mg/g dry wt).

Journal Article↗
PubMed1992

Antimicrobial activity of naphtoquinones and Allium extracts combined with antibiotics.

Combinations of antibiotics and known antimicrobial natural products, naphtoquinones and Allium extracts, were investigated. The chessboard broth method was applied to assess the activity of these combinations against aerobic and anaerobic bacteria. If no antagonism was observed, the combinations studied lead from partial to total synergism, mainly against aerobic bacteria.

Allium↗
PubMed1991

[Serum thyroglobulin and whole-body scanning as markers in the follow-up of differentiated thyroid carcinomas].

We have compared two "markers" in the follow up of post treatment (surgery and therapeutical use of I-131) differentiated thyroid carcinoma. In 153 patients, thyroglobulin (Tg) serum levels were measured after withdrawal of I-thyroxine therapy, before performing a whole-body scan (WBS) with iodine-131; in 55 of these patients, Tg was measured again after at least 45 days of I-thyroxine treatment. The patients were followed between 3 and 10 years, and there were 2713 matched studies. Our results indicate for both parameters, false positive and negative values; sensitivity (SE) for WBS was 89% and specificity (SP) 83%; Tg presents a SE of 86% and SP of 83%. Matching both parameters, SE was 95% and SP 98%. The causes of false results are discussed. Tg determinations under I-thyroxine treatment do not permit the establishment of absence of illness; 37.7% of patients with demonstrated metastases or relapse showed negative Tg values that reached pathological values after suspension of I-thyroxine treatment; another 41.4% with elevated Tg values under therapy reached these values after suspension of I-thyroxine. Both markers, when utilized at the same time, offer the best possibilities in the follow-up of differentiated thyroid carcinoma, when determinations are carried out after suspension of hormonal treatment.

Adenocarcinoma↗
PubMed1990

New procedure for direct bioautographic TLC assay as applied to a tincture of Ranunculus bulbosus.

A new procedure for TLC bioautographic assay using a flooding method to inoculate the developed plates is described. Details about several microbiological parameters allow good reproducibility for this method which appears rapid, easy to perform and requiring no specialized equipment. Significantly results obtained with a commercial tincture of Ranunculus bulbosus illustrate this method which can be extended to complex mixtures of natural products in order to isolate active fractions.

Biological Assay↗
PubMed1989

A seven year survey of antibiotic susceptibility and its relationship with usage.

Bacterial susceptibilities to 14 antibiotics of 7385 clinical isolates, belonging to six species of Gram-negative bacilli, were analysed during seven years (1980-86). The recovery of Serratia marcescens, Acinetobacter calcoaceticus and Pseudomonas aeruginosa increased while their sensitivity to antibiotics decreased significantly, especially to aminoglycosides and tetracycline. There were significant correlations between increase in antibiotic use and decrease in susceptibility. There was a striking relationship between third-generation cephalosporin use and increasing number of isolates of the species mentioned above.

Anti-Bacterial Agents↗
PubMed1987

[Antibacterial activity of species of the genus Allium].

Garlic, onion and shallot were tested for antimicrobial activity against pathogenic aerobic and anaerobic bacteria. The MIC of aqueous and petroleum ether extracts were determined. Garlic showed the greater activity; the combination garlic-antibiotic is synergistic against Acinetobacter calcoaceticus and leads to indifference against anaerobic bacteria. The active constituent is not probably allicin alone.

Allium↗
PubMed1985

Intraocular pressure in uremic patients on chronic hemodialysis.

Intraocular pressure (IOP) was measured before and after hemodialysis in 30 uremic patients receiving regular treatment. Osmolality, blood pressure and weight before and after dialysis were also determined. Low IOP of 11.4 +/- 2.7 and 11.5 +/- 3.1 mm Hg was found in the left and right eye, respectively. Following hemodialysis osmolality, blood pressure and body weight decreased significantly but IOP did not rise significantly. This study suggests that there is only a remote possibility for severe IOP increase following hemodialysis in uremic patients on chronic treatment.

Adolescent↗