Biomedical subjects

E Bárány

Publications and source records attributed to E Bárány.

At least 19 recordsLinked to original sources

PubMed2005

Iron status influences trace element levels in human blood and serum.

Food is the main source of trace elements for the general population. The gastrointestinal absorption of certain trace elements, e.g., cadmium, is strongly influenced by iron (Fe) status. This factor may also be relevant for the bioavailability of other trace elements. Therefore, we investigated relationships between Fe status indicators and trace element concentrations in blood and serum of 234 boys and girls at ages 15 and 17 years. Fe status was measured using serum ferritin (S-Ft), soluble transferrin receptor in serum (sTfR), and the ratio sTfR/S-Ft. The trace elements we investigated were, in blood, cadmium, cobalt, copper, zinc, selenium, rubidium, mercury, and lead, and, in serum, cobalt, copper, zinc, selenium, rubidium, tungsten, mercury, and lead. We found inverse correlations between Fe status and blood cadmium, blood or serum cobalt, or blood copper. There were positive correlations between Fe status and mercury concentrations. Selenium was positively correlated with sTfR. The relationships between Fe status and lead were equivocal. There were fewer correlations for serum than for blood, but the inverse relationships between Fe status and cobalt were equally strong in serum and blood. We found only occasional, and perhaps spurious, correlations with zinc, rubidium, and tungsten. In conclusion, previous indications that cadmium, cobalt, and copper are absorbed by transport mechanisms similar to that of Fe are supported by this study. Strong positive correlations between Fe status and mercury concentrations remain to be explained.

Adolescent↗

PubMed2000

Unexpected skin barrier influence from nonionic emulsifiers.

Skin disorders are often treated with creams containing various active substances. The creams also contain emulsifiers, which are surface-active ingredients used to stabilize the emulsion. Emulsifiers are potential irritants and in the present study the influence of stearic acid, glyceryl stearate, PEG-2, -9, -40, and -100 stearate, steareth-2, -10 and -21 on normal as well as on irritated skin have been evaluated with non-invasive measurements. Test emulsions were created by incorporating 5% emulsifiers in a water/mineral oil mixture (50:50). The emulsions and their vehicle were then applied to normal skin for 48 h and to sodium lauryl sulfate (SLS) damaged skin for 17 h in aluminum chambers. Twenty-four hours after removal of the chambers the test sites were evaluated for degree of irritation. In normal skin, the emulsifiers induced significant differences in TEWL but not in skin blood flow. Five of the emulsifiers increased TEWL. In SLS-damaged skin an aggravation of the irritation was expected. However, no differences regarding skin blood flow was noted from the emulsifiers. Furthermore, three emulsifiers unexpectedly decreased TEWL. These results highlight the possibility of absorption of these emulsifiers into the lipid bilayer, which increase TEWL in normal skin and decrease TEWL in damaged skin.

Administration, Topical↗

PubMed2000

Content of fragrance mix ingredients and customer complaints of cosmetic products.

BACKGROUND: In relation to the wide use of cosmetics, serious adverse effects are rare. Occasionally, unwanted effects such as contact dermatitis are reported. Allergic reactions to cosmetics are often caused by fragrances. OBJECTIVE: The aim was to investigate the content of fragrance mix (FM) ingredients in cosmetic products of the brand ACO HUD (Stockholm, Sweden) and the frequency of customer skin complaints about fragranced and unfragranced products over 4.5 years. METHOD: Content of FM ingredients in the fragrances used was both analyzed and requested from the suppliers. Customer complaints were those reported to the company. RESULTS: Between 1 and 7 of FM ingredients were present in levels of less than 0.1 to 770 ppm. The ingredients, in order of frequency, were geraniol, eugenol, hydroxycitronellal, alpha-amyl cinnamic aldehyde, isoeugenol, cinnamic alcohol, and oak moss. Cinnamic aldehyde was not found. No significant difference was found either between the frequency of complaints about products with and without fragrance (P = .21) or in a paired comparison of 17 formulas marketed with and without fragrance (P = .24). CONCLUSION: The study suggests that the investigated fragranced products had a low content of FM ingredients, which might explain the absence of a higher frequency of adversities. Furthermore, it appears that under such circumstances fragrances may be used without introducing an increased rate of spontaneous complaints of skin reactions.

Allergens↗

PubMed1999

Biophysical characterization of skin damage and recovery after exposure to different surfactants.

The majority of adverse skin reactions to personal-care products are presumed to be caused by irritant substances, like surfactants. In this study, different aspects of the irritant reaction after a single exposure to 8 surfactants were characterized during 2 weeks. Solutions of 2% sodium lauryl sulfate, 5% sodium C12-15 pareth sulfate, 5% sodium cocoyl isethionate, 10% disodium laureth sulfosuccinate, 10% sodium cocoamphoacetate, 10% cocamide DEA, 10% cocamidopropyl betaine and 10% lauryl glucoside, respectively, were applied to the forearm of 12 volunteers. Clinical assessment, an evaporimeter, a laser Doppler flowmeter and a corneometer were used for evaluation. The surfactants induced different degrees of irritation. Erythema, transepidermal water loss and skin blood flow exhibited a similar time course, which seemed to be inversely related to the delayed scaling and reduced skin capacitance. The mechanism of the damaging effect of the surfactants seems to be similar, although some minor differences were noted.

Adult↗

PubMed1990

[Structural differences in the structure of the ciliary muscles in eyes of primates. A histochemical and morphological study].

The ciliary muscle of the primate eye was stained histochemically with enzymes used to differentiate fiber types in the skeletal muscle. Differences between the outer meridional section and the rest of the muscle were found with all enzymes. Staining for myosin-ATPase with acid and alkaline preincubation, as well as for lactate dehydrogenase (LDH), resulted in a stronger reaction in the meridional section, while the reticular and circular portions showed minor activities. In contrast, succinate dehydrogenase (SDH) revealed a stronger activity in the reticular and circular muscle cells. Ultrastructurally, the meridional muscle cells contained fewer mitochondria, but more myofibrils in the cytoplasm, while circular and reticular muscle cells showed just the opposite. Therefore, the cells of the meridional ciliary muscle section resemble in some respects the rapid type-II skeletal muscle fibers, and the circular und reticular muscle cells are comparable to the slow type-I fibers of the skeletal muscle.

Animals↗

PubMed1987

Negative feedback regulation of intracellular Ca2+ and the slope of the dose-response curve.

Cytosolic calcium ions are known to act as an intracellular messenger. The response of the cell may be governed by a power of the internal Ca2+ concentration. This causes a very steep relationship between concentration and response. Dose-response curves of tissues acted on by external agonists are less steep. A possible explanation for this discrepancy is offered. During steady stimulation, which increases Ca2+ inflow and its cytosolic concentration, mechanisms which counteract the increased level by removing Ca2+ are likely to be activated. If these were stimulated by cytosolic Ca2+, they would constitute a negative feedback. If the removal mechanisms were governed by a power of the cytosolic Ca2+ concentration, the negative feedback would have positive co-operativity. A mathematical model is developed where entry of extracellular Ca2+ results from stimulation while a co-operative extrusion pump provides negative feedback. It is shown that, in the steady state, positive co-operativity in the extrusion pump is able to reduce the steepness of the dose-response curve.

Animals↗

PubMed1986

Carbonic anhydrase isoenzymes in the rat kidney. Effects of chronic acetazolamide treatment.

Biochemical, immunocytochemical and histochemical methods were used to study the effect of chronic acetazolamide treatment on carbonic anhydrase (CA) isoenzymes in the rat kidney. Male inbred rats (Lew/Mol) were treated with 15 mg kg-1 day-1 acetazolamide s.c. by Alzet minipump during 2-9 weeks; some animals had a drug-free period of 1-4 weeks before being killed. The renal content of CA II was higher in the acetazolamide-treated rats than in the controls, 178 +/- 10 vs 144 +/- 4.8 micrograms enzyme protein g-1 tissue (mean +/- SE). The distribution of CA isoenzymes did not change during or after chronic acetazolamide treatment. Thus, only CA II was detected in the kidney tubules by immunofluorescence using specific antisera against CA I, CA II and CA III. All animals showed a similar staining pattern, with intense cytoplasmic CA II staining in intercalated cells of collecting ducts, moderate staining in descending thin limbs of Henle, and weak cytoplasmic staining in proximal tubules and chief cells of collecting ducts. All animals also showed histochemical staining of cell membranes in proximal and distal tubules and thick limbs of Henle, suggesting the presence of a membrane-bound isoenzyme (CA IV). The only difference noted by histochemistry and immunocytochemistry was that the intercalated cells appeared bulkier and protruded more markedly into the tubular lumen in treated than in untreated animals. The functional importance of this finding is unclear. The observed changes in CA cannot alone explain why the effect of acetazolamide, in causing loss of bicarbonate and sodium, is self-limited on continued administration.

Acetazolamide↗

PubMed1984

Organic acid transport to the blood from the corpus striatum, the thalamus and the cerebellum of the rat.

Conscious rats were given intracerebral injections by preplaced microsyringes. The injectates were 0.3-0.5 microliters of 125I- and 131I-o-iodohippurate. One hour after injection the isotopes present in the unopened cranial cavity were measured by gamma spectrometry. Some animals received 200 mg/kg probenecid intraperitoneally and this reduced the rate of absorption from injectates into the corpus striatum to 65.7 +/- 12.6% of control; from injectates into the cerebellum to 57.1 +/- 9.8% of control. Dye injections showed that injections into the cerebellum did not remain in the parenchyma, in contrast to injections into the corpus striatum or thalamus. Probenecid was also given as 2.9% solution, pH 7, mixed with the iodohippurate in the microsyringe. It had no effect on injections into the cerebellum, reduced the rate of absorption from the corpus striatum to 80.9 +/- 3.2% of controls and that from the thalamus to 88.3 +/- 2.2%. The results indicate parenchymal probenecid-sensitive transport of iodohippurate from the corpus striatum and thalamus but failed to settle the matter for the cerebellum.

Absorption↗

PubMed1984

[Elimination of organic cations from the eye].

Substances injected into the vitreous cavity leave the eye partly by diffusion into the flowing aqueous, but sometimes also by other mechanisms. To look for such other mechanisms removing organic cations from the rabbit eye, 5 labeled quaternary ammonium compounds were injected intravitreally, mixed with labeled sucrose. The latter leaves essentially by way of the aqueous only. After predetermined times had elapsed the rabbits were killed, and the radioactivity remaining in each eye was measured after combustion of the dried eye bulb. The anticholinergic drug Emepronium disappeared faster than sucrose but only after a delay of many hours. The main experiments were therefore concerned with the time interval 24-48 h after injection. The N- hexylhomologue of Emepronium ' Cetihex ' and the non-sedative antihistamine Aprobit were not eliminated faster than sucrose during this time interval. Since the molecular weights of these quaternaries are similar to that of sucrose and their free diffusion rate should be similar, the present experiments over a limited time interval have proved the existence of an elimination mechanism (besides aqueous flow) only for Emepronium. Tetramethylammonium and tetraethylammonium disappeared markedly faster than sucrose. Since there is no satisfactory way to take their much lower molecular weight into account, the question of a special system for these cations remains open.

Animals↗

PubMed1983

Iris delay, a neglected factor in aqueous humour dynamics. A study in the cynomolgus monkey (Macaca fascicularis).

A method is described, intended for measuring the rate--over a short period of time--of aqueous humour outflow in non-anaesthetized primates. [125I] and [131I]-o-iodohippurates were infused s.c. at an interval into the conscious Cynomolgus monkey so as to give two time-displaced plasma curves. The isotope concentrations were measured in plasma by frequent sampling over the first 1-2 hr and in aqueous humour at the end of the experiment under brief anaesthesia. The coefficient of diffusion (kdiff) between plasma and aqueous, and the coefficient of loss (kout) out of the anterior chamber were calculated by making the usual assumptions about aqueous dynamics. Topical treatment of one eye with timolol consistently reduced kout, as expected, but many control values for kout were lower than expected or (impossibly) negative. Examination of the data reveals a likely source of error emanating from the commonly made assumption that diffusion of marker substance (in our case iodohippurate) from plasma to aqueous humour is proportional to the instantaneous concentration difference between plasma and aqueous. In fact, there may be a delay of several minutes during which the substance negotiates the stroma and anterior boundary layer of the iris. Evidence is presented that variation between and within individual monkeys may stem from the highly variable anatomy of the iris and from changes in sympathetic tone operating on the blood vessels and perhaps the anterior boundary layer.

Animals↗

PubMed1983

The liver-like anion transport system in the rabbit uvea does not eliminate iodipamide from the eye.

Iodipamide is known to be actively taken up in vitro by the rabbit iris-ciliary process preparation. This uptake is partly resistant to high concentrations of hippurate and the resistant part has been called the 'liver-like' system. In vivo iodipamide is eliminated from the rabbit eye after injection into the vitreous by a saturable process. This process is hippurate-sensitive and no role for any hippurate-resistant system was found. Two explanations for the discrepancy between the results in vitro and in vivo are offered: (1) Iodipamide may be a less than perfect model substance for physiological compounds that normally are transported by a liver-like system from the vitreous cavity and the posterior aqueous humour to the blood. (2) Iodipamide is a model for compounds that are taken up by the non-pigmented epithelium of the ciliary processes by a liver-like system and transported to the pigmented epithelium for metabolic modification.

Animals↗

PubMed1982

The binding properties of the muscarinic receptors of the cynomolgus monkey ciliary body and the response to the induction of agonist subsensitivity.

1 The binding properties of the muscarinic receptors in the ciliary muscle of cynomolgus monkeys have been evaluated. 2 The concentration of receptor binding sites is the highest yet reported. As found in many species and tissues, there are subclasses of agonist binding sites. Agonist binding is not affected by the non-hydrolysable guanosine triphosphate (GTP) analogue, GppNHp, suggesting that these receptors are not linked to adenylate cyclase. 3 Ciliary muscles made subsensitive by treatment with muscarinic agonists have a decreased receptor concentration but no other changes in the binding properties of the receptors could be detected.

Animals↗

PubMed1979

Early lens changes in Macaca fascicularis monkeys under topical treatment with echothiophate or carbachol studied by slit-image photography.

Cynomolgus monkeys were given topical treatment with echothiophate or carbachol, and the lens changes were followed by slit-image photography. Both drugs caused an early retrodisplacement of the anterior zone of disjunction due to swelling of the most superficial lens cortex. Deeper layers of the cortex did not swell. The exact cause of the swelling is not known, but there must be a true cholinergic link. Accommodation as such is not the cause, since (1) the effect was seen also in a monkey eye which had its ciliary muscle disinserted from the scleral spur and therefore had little accommodation left and (2) acute accommodation produced by systemic pilocarpine did not cause the effect. Anterior subcapsular opacities were quantified and appeared very early in the echothiophate-treated eyes but were not seen with the doses of carbachol used.

Accommodation, Ocular↗

PubMed1978

Time course of light induced changes in pilocarpine sensitivity of rat iris.

Pigmented rats were kept under different light regimens for 1--20 days. Supramaximal light was used. The response of the iris sphincter in enucleated eyes with their cornea intact was tested in vitro. Pilocarpine at 6 X 10(-5) M was used as a standard stimulus. In agreement with previous authors there was a marked difference between constant light treated (subsensitive) eyes and dark treated (supersensitive) ones. Animals pretreated to reach maximal sub- and supersensitivity and then shifted to the opposite regimen, showed that reversal was a gradual process starting within a few hours. Full reversal had not been reached at 72 h. The two curves of sensitivity vs time intersected around 24 h. The time constants of the two curves were approximately equal. Light regimens using intermittent light shifting every 1, 3, 6 or 12 h gave intermediate results.

Animals↗

PubMed1970