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Biomedical subjects

R Brun

Publications and source records attributed to R Brun.

At least 37 records · Page 2Linked to original sources
PubMed1979

Nickel in food: the role of stainless-steel utensils.

Nickel may be found in prepared foods (tinned foods) at markedly higher concentrations than the safe threshold laid down for hypersensitive patients. Some foodstuffs cooked in stainless-steel utensils attack the metal and thus contain much more nickel than when enamel or aluminum saucepans are used. Among the natural organic acids which may be responsible for dissolving stainless-steel, oxalic acid is the most active at equivalent concentrations.

Cooking↗
PubMed1979

[Guinea pig nipple as a model for the investigation of melasma (author's transl)].

The nipples of male tan guinea pigs were used to test the effects on the skin of oral contraceptive pills and drugs. The daily topically applied doses were 1/2,000 of a pill. After 3 weeks, the nipples treated with solutions of ethinyloestradiol-containing pills had grown (200-300%), the epidermis showed acanthosis (150-250%) and strong hyperpigmentation. Mestranol-containing pills as well as pure progestogen substances did not produce these effects.

Animals↗
PubMed1979

[Alimentary nickel and contact eczema (author's transl)].

By atomic absorption spectrometry, nickel was analysed in many foodstuffs. The results of these determinations are given in detail. Nickel present in vegetables comes primarily from the soil but secondarily from stainless-steel cooking utensils.

Dermatitis, Contact↗
PubMed1978

[Hyperthyroidism in older patients].

This study comprises 81 thyrotoxic patients with onset after the age of 60. In elderly persons, toxic multinodular goiter is the most common cause (68%) of hyperthyroidism, followed by solitary thyroid nodules (16%) and Graves' disease (16%). Cardiovascular disorders (cardiac failure, arrythmias etc.) constitute the first and often the only symptom in 62% of the cases. The other forms of appearance are both various and deceptive: depression, slight fever, asthenia or nausea. Separate analysis of the three forms of hyperthyroidism did not reveal clinical, biological or therapeutic differences between them, except an inferior rate of captation for the toxic nodules. Isolated measurement of T3 or T4 is often insufficient to confirm the diagnosis because either of these hormones may appear at a normal rate. In three cases only the free thyroxin index was pathological on first determination. The authors have established that the autonomous nodules are larger and more active after, rather than before, 60 years of age, and have attempted to define their morphological identity. The results of the treatment are analyzed and preference is expressed for radioactive iodine in every form of hyperthyroidism.

Aged↗
PubMed1978

Effect of ethidium bromide on growth and morphology of Leishmania tarentolae promastigotes in vitro.

Incubation of Leishmania tarentolae promastigotes in 0.01 microgram/ml ethidium bromide in Neo Ye medium for 96 h resulted in 60% inhibition of cell growth and 91% dyskinetoplasty. After 48 h incubation in ethidium bromide over 50% of the cells were scored dyskinetoplastic by light microscopy although the electron microscopical examination revealed that most promastigotes contained at least a small amount of kDNA. A few of the treated cells undergoing division contained two kinetoplasts--one devoid of kDNA and the other with a reduced amount of kDNA as seen in the electron micrographs.

Ethidium↗
PubMed1977

Effect of berenil on growth, mitochondrial DNA and respiration of Leishmania tarentolae promastigotes.

Incubation of Leishmania tarentolae promastigotes in 1.0 microgram/ml Berenil for 96 hr resulted in approximately 33% inhibition of cell growth and approximately 42.5% dyskinetoplasty in the cell population. The buoyant density of kinetoplast DNA (kDNA), p = 1.703 g/ml, remained unchanged after 96-hr exposure to the drug. Endogenous respiration as well as proline- and glucose-induced respiration dropped markedly after 36-hr exposure to Berenil. This drop occurred approximately 12 hr before the onset of dyskinetoplasty, a result which suggests that this drug adversely affects mitochondrial respiratory activity of the promastigotes.

Amidines↗
PubMed1977

A new semi-defined medium for Trypanosoma brucei sspp.

A new, easy to prepare semi-defined medium for the cultivation of trypanosomes of the T. brucei complex is introduced. Containing the two commercially available media MEM (Minimum Essential Medium) and Medium 199 TC45 as well as 10% inactivated foetal calf serum (fcs), the medium supports optimum growth and direct adaptation of bloodstream forms. Growth characteristics, glucose uptake, amino acid utilization and the ultrastructure of trypanosomes grown in this medium are described briefly.

Amino Acids↗
PubMed1976

Quantitative ultrastructural investigations of mitochondrial development in Leishmania donovani during transformation.

The ultrastructure of the mitochondrion during transformation of Leishmania donovani from amastigote to promastigote stages was studied by morphometric analysis. There was a slight but significant decrease in relative mitochondrial volume (Vvmi) during transformation. This decrease was linear with time for at least 27 hr. No change in relative lipid inclusion volume (Vvli) was observed during transformation. The ratio of inner to outer mitochondrial surface membrane densities (Svmii:Svmio) also remained unchanged. Although the relative number of cristae remains unchanged after transformation, there is an increase in cristae number in the portion of the kinetoplast opposite the flagellum.

Animals↗
PubMed1976

A simple monophasic medium for axenic culture of hemoflagellates.

An inexpensive, easily prepared monophasic medium which supports continuous culture of Leishmania donovanì (approximately 4 X 10(7) cells/ml/day 5) and L. tarentolae (approximately 3.5 X 10(7) cells/ml/day 5) promastigotes has been developed. This medium, designated HO-MEM, is a modified Eagle's minimal essential medium with Spinner's salts and 10% fetal calf serum. Epimastigotes of Trypanosoma cruzi, Costa Rica strain, also grew well in HO-MEM (approximately 2 X 10(7) cells/ml/day 5) but cells of the Corpus Christi strain grew poorly in the medium. The initial inoculum for all of the above culture systems was 3 X 10(5) cells which means that there was approximately 100-fold increase in cell number within 5 days of culture. Average doubling time for L. donovani in HO-MEM during log growth phase was 10 to 12 hr; this shortened to 9.25 hr at mid-log growth (day 2). The optimal pH range for L. donovani was 7.2 to 7.4 and optimal culture temperatures were 25 to 26 C. A change was seen in the average size distribution of L. donovani promastigotes during the growth cycle with smaller cells predominating each succeding day of culture. HO-MEM is a good medium for transformation of L. donovani amastigotes to promastigotes (60 to 80% in 48 hr).

Animals↗
PubMed1976

[Photosensitization of the skin and fluorescence spectra (author's transl)].

We have carried out spectrofluorometric determinations of numerous substances such as drugs, chemicals and plants in order to find out whether there is a correlation between fluorescence data and photosensitization of the skin. A hypothesis on the mechanism of photosensitization is discussed and the data on the fluorescent properties of some 50 products is given.

Humans↗