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Biomedical subjects

A Lukacs

Publications and source records attributed to A Lukacs.

At least 19 recordsLinked to original sources
PubMed2001

Relative variation to received dose of some erythrocytic and leukocytic indices of human blood as a result of low-level laser radiation: an in vitro study.

OBJECTIVE: This study investigated the in vitro effects of low-level laser radiation (LLLR) on selected rheologic constants of the human blood. The variations of CBC parameters to the received dose were determined, as well as of blood viscosity (an erythrocyte aggregation index), as a research method for some structural alteration of blood proteins. This was also confirmed by the electrophoretic study of plasma proteins from the irradiated blood. METHODS: Fresh blood samples (whole blood) from 16 adult regular blood donors were irradiated with a He-Ne laser (lambda = 632.8 nm; power output = 6 mW; mean irradiance on blood samples approximately 180 mW.cm-2; beam spot diameter approximately 2 mm), operating in continuous wave. Doses ranged between 0 (control sample) and 9.346 J.cm-3.EDTA (for CBC and viscosity measurements) or citrate (for electrophoresis) anticoagulant was used. Measurements were performed before (control samples) and after irradiation. In most of the cases, the measurements were made immediately after irradiation. In some cases, the measurements were made after 24 or 48 h after irradiation, respectively, to conclude whether the modifications caused from irradiation occur in time, or immediately after irradiation. RESULTS: Following irradiation, marked variations of some erythrocyte and leukocyte indices and changes of the erythrocyte aggregation (viscosity), as a function of received dose, were observed. Significant differences between control and irradiated blood samples were found for the following rheologic factors: RBC (in 22.2% of cases); HGB (26.8%); HCT (82.4%); MONO and GRAN (36.7%); viscosity (82.5%). From the plasma proteins: albumin (22.2%); alpha 1 globulin and gamma globulin (18.5%); fibrinogen (70.4%). In most of the cases, remarkable effects (maxima) were noticed around 1.2 J.cm-3 dose value. We consider this dose value as optimal, one that can lead to beneficial effects. The cell membrane integrity was not affected from irradiation, for doses between 0 and 9.346 J.cm-3, and will probably not even be affected at higher doses (see MCV and MCHC behavior). CONCLUSIONS: The effect of LLLR on red blood cells confirms the nonresonant mechanism of this biostimulating effect, by the changes occurring in the cell membrane (in our case, blood cells), by revitalizing of red blood cell functional capacities and by several biochemical effects at the membrane's level. These are to be studied thoroughly in future studies. The physical-biochemical and biological effects caused by LLLR on blood can influence the physical-chemical parameters needed for the long-term storage of blood products. These effects can also lead to a quicker revitalization of the erythrocyte membrane (which was subjected to the action of some physical and biochemical factors during the preservation process), to perform its oxyphoric function in transfusion procedures.

Adult↗
PubMed2000

Effect of low-level laser radiation on some rheological factors in human blood: an in vitro study.

OBJECTIVE: The purpose of this study was to investigate the in vitro effects of low-level laser radiation (LLLR) on some rheological factors of the human blood, such as complete blood count (CBC) parameters and blood sedimentation rate (BSR). We were mainly concerned with the alterations caused by LLLR action on blood cells (erythrocytes and leukocytes) of fresh blood obtained from apparently healthy adult patients. We used low doses ranging between 0.80 J x cm(-3) and 4.40 J x cm(-3), at the very low-power densities of the laser radiation, so as not to damage the cell structure and not to alter in an undesired manner their functions. METHODS: Blood samples were taken from 22 volunteers. Where health problems existed, they were indicated for each case. The parameters mentioned above were measured before (control samples) and after irradiation. A He-Ne laser, operating in continuous wave, as a radiation source (632.8 nm, 1 mW, intensity of 8 x 10(-2) W x sr(-1), mean power density incident on blood samples around 30 mW x cm(-2), beam spot diameter 2 mm) was used. The measurements were performed immediately after irradiation. Only the erythrocyte complex was irradiated. EDTA anticoagulant was used. RESULTS: The measurements using a computerized hemoanalyzer type SERONO showed significant differences between control and irradiated blood samples concerning the following parameters: RBC (in 22% of cases), HGB (47.3%), HCT (84.2%), RDW (11%), PLT (5.26%), MPV (33.3%), WBC (5.26%), MONO (26.3%), and GRAN (63.15%). In the case of BSR (44%), the significant differences were noticed especially in the cases of patients suffering from some acute or chronic diseases. Nonsignificant differences were noticed in the cases of MCV, MCH, MCHC, RDW, and LYMPH. CONCLUSIONS: This study has shown that LLLR, even though used at low doses and low power densities, produced some changes of the rheological factors of the blood, as follows: a revitalizing and regenerating effect on mitosis stimulation and a nondamaging and biostimulating effect on the cell membrane (by keeping unmodified MCV, MCH, and MCHC). In 3 cases out of 22, hemolysis (complete or partially) occurred, but we are not yet sure whether this was caused by laser exposure or by certain environmental physical factors.

Adult↗
PubMed1998

[Topical administration of metronidazole gel as an effective therapy alternative in chronic Demodex blepharitis--a case report].

BACKGROUND: Blepharoconjunctivitis is the commonest manifestation of ocular rosacea. Cilia epilation proves Demodex folliculorum, considered an etiologic factor in rosacea. Complications and differential diagnosis include dry eyes, seborrheic, bacterial and allergic blepharoconjunctivitis. Treatment involves lid scrubs and mercury ointment, its duration is limited to 6 weeks under frequent control due to corneal toxicity of mercury. HISTORY AND SIGNS: 30-year-old female with complaint of red, irritated eyes for 21 years, resistant to antibiotics and antiallergics. General medical history unremarkable, mercury allergy. Acuity: R/L 20/20. Biomicroscopy: red, thickened eyelid margins, crusty debris on rarefied, partially broken lashes, conjunctival telangiectasia, low tear meniscus, further ophthalmologic examination unremarkable. DIAGNOSIS: chronic Demodex blepharoconjunctivitis. THERAPY AND OUTCOME: Conventional treatment was contraindicated due to mercury allergy. Alternative oral minocycline 100 mg daily brought no subjective nor objective relief. Combination of lid scrubs and 2% Metronidazole gel relieved symptoms and halved number of mites after 1 month, lashes grew again after 2 months. Treatment was discontinued after 6 months as Demodex folliculorum proof remained negative. No relapse occurred during 1 year. CONCLUSIONS: Topical Metronidazole 2% proved to be an effective treatment of chronic Demodex blepharoconjunctivitis in our case and thus may offer a new and save alternative to existing therapies. Neither ocular nor systemic side effects occurred. Controversial theories on the aetiology of blepharitis are discussed.

Administration, Topical↗
PubMed1997

[Lisch nodules. Markers of neurofibromatosis 1 and immunohistochemical references for neuroectodermal differentiation].

Iris nodules in neurofibromatosis I have become an important tool in the differential diagnosis of phakomatoses. The clinical appearance and importance of these nodules first recognized by Karl Lisch in Munich in 1937. The diagnosis and differential diagnosis of Lisch nodules are illustrated. The importance of iris nodules in genetic counselling of patients and their relatives is discussed, with emphasis on monosymptomatic cases. Histologically Lisch nodules are formed by aggregations of oval to round cells that form dome-shaped papules on the anterior layer of the iris. Immunohistochemically these cells are characterized by positive staining with antibodies against vimentin and S-100 protein. This proves their ectodermal differentiation. Thus Lisch nodules can be seen as a direct manifestation of neuroectodermal disturbances in neurofibromatosis I.

Diagnosis, Differential↗
PubMed1995

[Intraoperative anaphylaxis due to natural latex in a 3-year-old boy].

A nearly three-year-old boy with a genitourinary malformation, which had already been operated on several times, developed generalized urticaria, facial swelling and bronchospasm within 15 minutes of the induction of anaesthesia. The signs quickly responded to the administration of methylprednisolone (32 mg), clemastine (10 mg) and ranitidine (25 mg). There was a twofold positive immediate reaction in the prick test to natural rubber latex (white and brown), and specific IgE was demonstrated against the latex (2.58 kU/l). On the other hand, prick tests with perioperatively administered drugs and an oral provocation test with an antibiotic administered in the perioperative period were negative. The history of itching caused by an indwelling bladder catheter, vesicles on the lips after sucking on a rubber dummy and the described findings on examination both point to the natural rubber latex as the responsible allergen. No complications occurred three months later during a surgical intervention under administration of steroids and H1- and H2-receptor antagonists, as well as avoidance of materials made of natural rubber latex.

Anaphylaxis↗
PubMed1995

The influence of the pH-value on the growth of Brevibacterium epidermidis in continuous culture.

Brevibacterium epidermidis is a major component of the bacterial flora of certain skin surface biotopes, characterized by a comparatively high pH-value. The presence of Brevibacterium epidermidis seems to be linked to the production of malodour. Skin surface pH has been found to be a major factor of bacterial growth on the skin. In order to find out if this might also apply to Brevibacterium epidermidis, this microorganism was grown in vitro in continuous culture using a chemostat. Specific growth rate and density of colony forming units were well correlated. While the organism grew readily from pH 5.5 to 8.5, this was not the case with a pH of 5.0. Thus pH-shifts induced by cosmetic procedures can only prevent unpleasant body odour due to abundant growth of bacteria if the pH-value is decreased to 5.0 or less.

Brevibacterium↗
PubMed1992

Influence of the pH-value on the growth of Staphylococcus epidermidis, Staphylococcus aureus and Propionibacterium acnes in continuous culture.

A cutaneous isolate of Staphylococcus epidermidis, Staphylococcus aureus and Propionibacterium acnes was grown in continuous culture at varying pH-values ranging from 5.0 to 8.5. In terms of the specific growth rate as well as the bacterial density during the plateau phase there were remarkable differences. In particular, Propionibacterium acnes grew much better in the pH 6.0 to 7.0 range than in a more acidic or alkaline milieu. Staphylococcus epidermidis resembled Staphylococcus aureus showing no major difference at pH 5.5 and 7.0. These findings substantiate the hypothesis that minor changes of the pH in the pH 5.5 to pH 6.0 range as to be induced by chemically neutral or alkaline skin cleansers on the human skin surface can increase the number of propionibacteria but not staphylococci remarkably due to the relative alkalinity by itself.

Culture Media↗
PubMed1991

Dermatophytosis in children and adolescents: epidemiological, clinical, and microbiological aspects changing with age.

During a four year period, a total of 84 cases of dermatophytosis were seen in patients from 0 to 17 years of age attending our out-patient department. The sex distribution was about equal in preadolescents. Males predominated among adolescents. A peak incidence at early school age was due to cases of tinea capitis, mainly caused by Microsporum canis. A peak among adolescents was due to cases of tinea pedis, mainly caused by Trichophyton rubrum. In general, patients with Trichophyton rubrum infections were older than those with other types of dermatophytosis (p less than 0.05). Dermatophytosis due to Microsporum canis was most frequently seen in January and in September (p less than 0.01). Although onychomycosis due to dermatophytes was a comparatively rare disease, it did occur within all age subgroups. Entities which were very frequent in former times and which have become rare during the last decades, such as tinea capitis due to Trichophyton schönleinii, still contribute to the spectrum of dermatophytosis in childhood.

Adolescent↗
PubMed1991

Influence of albumin on itraconazole and ketoconazole antifungal activity: results of a dynamic in vitro study.

The relevance of intense protein binding to the antifungal activity of azole compounds is still a matter of debate. The influence of albumin on the antimicrobial activity of ketoconazole and itraconazole, which exhibit very strong plasma protein binding (99 and 99.8%), was evaluated in vitro. Candida albicans was exposed to continuously changing azole concentrations corresponding to drug levels in serum following an oral dose of 200 mg. Total as well as free drug levels in serum were simulated. The incubation medium was free of proteins or contained 4% human serum albumin. Itraconazole levels reflecting free drug concentrations in humans did not reduce the growth rate of C. albicans, as compared with controls (difference in the log CFU per milliliter at 12 h, 0.03 +/- 0.09), whereas total drug levels were as active in the presence of 4% albumin (mean difference, -0.61) as in its absence (-0.75). The same was true for ketoconazole, except that free drug levels were also active (-1.21 versus -1.39 for total drug levels). This result was due to the higher ketoconazole levels in humans. Thus, in terms of routine susceptibility testing, in vitro total drug levels can be considered relevant.

Antifungal Agents↗
PubMed1991

Do cutaneous coryneform bacteria produce short-chain fatty acids in vitro?

According to an opinion shared by many, human axillary and inguinal odour is related to short-chain fatty acids produced by gram-positive bacteria. Especially coryneform bacteria are said to produce these odiferous substances. After sampling 22 different strains of coryneform bacteria we cultured them for 48 h in a rich medium. Short-chain fatty acids were extracted afterwards by shaking the liquid medium with ether. Gas chromatography was used for detection. Only one of the tested bacteria produced propionic acid. Acetic acid, (iso)butyric acid or (iso)valeric acid could never be detected. The production of substances of the short-chain fatty acid type might, however, be a consequence of the particular substrate found under physiologic conditions by these organisms in human apocrine sweat. The theory that the metabolism of these skin bacteria necessarily produces short-chain fatty acids could not be supported. Another explanation might be that unspecific secreted enzymes of the bacteria are responsible for the production of short-chain fatty acids by a cleavage of skin surface lipids.

Actinomycetales↗
PubMed1990

Skin tissue fluid levels of cefotiam in healthy man following oral cefotiam hexetil.

Cefotiam hexetil is a pro-drug of cefotiam available for oral administration. To evaluate cefotiam concentrations at the active site in skin and soft-tissue infections, drug levels in skin suction blister fluid (SBF), cantharides blister fluid (CBF) and serum were determined. Six healthy subjects received oral cefotiam 400 mg as cefotiam hexetil. On an other day 200 mg was injected intravenously. Following the oral dose, the bioavailability of cefotiam was 45.5%, and the maximum concentration in serum of 2.6 mg.l-1 was obtained at 2.1 h. Peak concentrations in both types of blister fluid (0.9 mg.l-1) were significantly lower than after the iv dose (SBF 1.4 mg.l-1, CBF 1.5 mg.l-1), and the peak levels occurred later (3.3 versus 1.5 h in CBF). Despite the delay, the extent of penetration was about 100% following either mode of administration (SBF, iv dose 112%, oral dose 117%). The cefotiam level in skin blister fluids declined significantly more slowly than the serum level. Following the oral dose, the mean terminal half life was serum 0.8 h, SBF 2.6 h and CBF 4.6 h. Cefotiam concentrations in the blister fluids were close to the MIC90 of Staphylococcus aureus, S. epidermis and H. influenzae and exceeded the MIC90 of Streptococci, E. coli and Proteus mirabilis. Thus, the oral administration of cefotiam 400 mg t.i.d. should be curative in the majority of bacterial infections of the skin and soft-tissues.

Administration, Oral↗
PubMed1990

Levels of itraconazole in skin blister fluid after a single oral dose and during repetitive administration.

Oral itraconazole is effective in the treatment of mycoses. To measure its concentrations in the tissue, levels of total and non-protein-bound itraconazole were determined in serum, suction-induced blister fluid, and cantharides-induced blister fluid. Six healthy subjects received 200 mg as a single dose, followed by 100 mg/day for 10 days. Itraconazole binding in suction-induced blister fluid (99.54%) and cantharides-induced blister fluid (99.77%) was calculated from plasma protein binding (99.8%). The single-dose study showed the drug levels in blister fluid to increase more slowly than those in serum. The terminal half-life of itraconazole in serum was 22.5 +/- 3.2 hours. Suction- and cantharides-induced blister fluid levels declined in parallel. After the final dose, itraconazole penetration into cantharides-induced blister fluid was only 70%. Moreover, trough levels of unbound itraconazole in suction- and cantharides-induced blister fluid were 0.239 +/- 0.115 and 0.334 +/- 0.101 ng/ml and thus were significantly lower than free itraconazole levels in serum (0.422 +/- 0.125 ng/ml). Thus a distribution equilibrium between serum and blister fluids was not obtained. Free drug concentrations in suction- and cantharides-induced blister fluid were far lower than the minimal inhibitory concentration values for Candida ssp. and dermatophytes.

Administration, Oral↗
PubMed1989

[Multi-step increase in resistance of Neisseria gonorrhoeae isolates after repeated in-vitro subinhibitory concentrations of second-generation quinolones].

Five recent gonococcal isolates were exposed to subinhibitory concentrations of several antibiotics in vitro 25 times. In the presence of rifampicin all strains quickly became resistant. In the presence of penicillin, enoxacin and ciprofloxacin, antimicrobial susceptibility also decreased. Here development of resistance, however, corresponded to the multi- and not to the one-step type. It seems remarkable that even at the end of the experiments no strain grew at concentrations of ciprofloxacin exceeding 0.064 mg/l. In conclusion, quick development of resistance need not be expected after the introduction of newer quinolones into the therapy of gonorrhoea on a large scale.

Anti-Infective Agents↗
PubMed1989

Skin blister fluid levels of ketoconazole during repetitive administration in healthy man.

Ketoconazole administered orally is used in the treatment of superficial and deep mycoses. To evaluate its active concentrations in skin tissue, serum, suction blister fluid (SBF), and cantharides blister fluid (CBF) levels of total and non-protein bound ketoconazole were determined. In general, only the free drug is considered to be the active one. Six healthy subjects received 200 mg once daily for 5 days. Total ketoconazole concentrations were determined by HPLC. The unbound fractions of ketoconazole in SBF (2.3%) and CBF (1.2%) were calculated from plasma protein binding (99.0%). Before the ultimate dose, levels of unbound ketoconazole in SBF and CBF were 0.64 +/- 0.16 and 0.70 +/- 0.25 ng/ml and were thus in accordance with free ketoconazole serum levels (0.52 +/- 0.24 ng/ml; p greater than 0.05). Furthermore, following the ultimate dose, the areas under the blister fluid level-time curves of unbound ketoconazole did not differ from the respective areas under the serum level time curves, thus distribution equilibrium between serum and skin blister fluid was obtained. Peak concentrations of free ketoconazole were (SBF) 8.6 +/- 2.9 ng/ml and (CBF) 8.9 +/- 2.3 ng/ml. Free concentrations in SBF and CBF were far below the MIC values for dermatophytes and Candida ssp. reported in the literature, leaving the concentration-effect relationship of ketoconazole still open for discussion.

Adult↗
PubMed1989

Bactericidal effect of cefodizime against beta-lactamase-producing Neisseria gonorrhoeae in vitro. A comparison of level profiles in serum and tissue after intramuscular and intravenous administration in man.

Serum and skin suction blister fluid (SBF) level profiles as well as the profile in the hypothetical peripheral compartment in man after the single intravenous application of 1 g of cefodizime and the corresponding serum level profile after intramuscular application were simulated in the presence of beta-lactamase-producing gonococci. A rapid reduction of bacterial density was observed under each of these conditions indicating clinical efficacy of both treatment protocols in uncomplicated gonorrhoea. Considering the different level profiles in more detail both serum level profiles after intravenous and intramuscular injection turned out similarly effective: while the time needed for a 99% reduction of gonococcal density (t99%) was slightly shorter with the intravenous profile (1.45 vs. 1.68 h), the maximum relative reduction was somewhat smaller, expressed by a higher kn value (0.00024 vs. 0.00010%). The drug level profile in the hypothetical peripheral compartment proved on the whole equally effective as the serum level profiles. The suction blister fluid level profile, however, showed an inferior antigonococcal activity (kn = 0.00076%, t99% = 2.08 h). This demonstrates the value of the determination of SBF levels and their inclusion in in-vitro simulation experiments.

Cefotaxime↗
PubMed1988

[Microbial flora and odor of the healthy human skin].

The microflora resident on human skin shows great interindividual and intraindividual differences. It is essentially composed of micrococci, staphylococci, aerobic and anaerobic coryneforms as well as pityrosporum species which, in accordance with the different environment in the different regions of the body, are in a steady state. With increasing age, human skin microflora undergoes qualitative changes: the streptococci, which are found in infants, disappear and coryneform bacteria occur, which are mainly responsible for odor production. Anaerobic propionibacteria are more numerous in juveniles and young adults, a fact that may be explained by increased sebum production. Only the coryneform bacteria are able to produce the typical axillary odor by decomposition of apocrine sweat. Cocci, however, obviously do not have this capacity. It remains to be established which substances participate in odor production. With sensitive chromatographic methods amino acids, steroids and free fatty acids were detected, which could be related to body odor. There are possibly only a few commonly occurring odorous substances. The necessity of analyzing these substances is stressed.

Amino Acids↗
PubMed1988

[Efficacy of ofloxacin against Neisseria gonorrhoeae].

Two beta-lactamase producing Neisseria gonorrhoeae strains with differing susceptibility to ofloxacin according to the minimum inhibitory concentration were exposed to the serum level time course of this chemotherapeutic agent in vitro. Within one hour, the bacterial density was markedly reduced, after another hour gonococci could not be subcultured anymore. In a comparative experimental setting the new cephalosporins have not led to total gonococcal eradication although they are also most efficient in gonorrhea. Therefore, quinolones such as ofloxacin should be also considered when it comes to gonorrhea treatment.

Anti-Bacterial Agents↗