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Biomedical subjects

K Becker

Publications and source records attributed to K Becker.

At least 541 records · Page 30Linked to original sources
PubMedDate not supplied

Effect of cytokines and lipopolysaccharides on HIV infection of human macrophages.

Human blood-borne monocytes (MO) differentiating into mature macrophages (MAC) were cultured on hydrophobic Teflon membranes. The cells were infected with two different monocytotropic HIV isolates: HIV1D117III obtained from a perinatally infected child, and HIV2D194 obtained from an AIDS patient who suffered exclusively from neurological symptoms. Virus production monitored by reverse transcriptase activity and HIV-antigen ELISA in cell-free supernatant was of a high level and continued for several weeks. To investigate possible modulatory pathways interfering with HIV infection in MAC we tested various recombinant cytokines as well as bacterial lipopolysaccharides (LPS) in our culture system. Whereas interleukin-1 (IL1) accelerated and increased HIV replication in MO/MAC, the interferons (IFN) alpha, beta and gamma effectively suppressed or delayed infection depending on the concentration used. Suppression was seen at concentrations as low as 0.3 U/ml and was most effective when the IFN were given prior to infection. No effect was observed with IL6 up to 2,000 U/ml. LPS affected virus infection in a complex manner: at 1-100 ng/ml virus replication was inhibited, but it was enhanced at subnanogram concentrations (25-100 pg/ml).

Cytokines↗
PubMedDate not supplied

The German Environmental Survey 1990/1992 (GerES II): a representative population study.

The German Environmental Survey (GerES) is a large-scale population study which has repeatedly been carried out in Germany. GerES I was conducted in 1985/1986 followed by GerES IIa in 1990/1991 (West Germany) and GerES IIb in 1991/1992 (East Germany). GerES III is currently run in both parts of Germany. The main goal of the surveys is to analyse and document the extent, distribution and determinants of the exposure to environmental pollutants of the German general population. Field work is conducted using a combination of several tools, including questionnaires, interviews, human biomonitoring, and indoor and outdoor environmental samplings. This paper describes the design of GerES II, and gives a general outline of the field work and the analytical procedures used. In GerES II, about 4000 adults were representatively selected from the German population with regard to age, gender and community size. Approximately 700 children were also included. Arsenic, cadmium, copper, chromium, lead, and mercury were determined in blood, morning urine and/or scalp hair. In addition, samples were taken and analysed to characterise exposure in the domestic environment (indoor air, house dust, drinking water). The contribution to exposure of food was also studied. Exposure to volatile organic compounds (VOCs) was determined by personal sampling.

Adolescent↗
PubMedDate not supplied

The German Environmental Survey 1990/1992 (GerES II): cadmium in blood, urine and hair of adults and children.

As a follow-up of an earlier population study carried out in West Germany in 1985/1986 (GerES I), a nationwide Environmental Survey was conducted in Germany in 1990-1992 (GerES II). It was the aim of these studies to obtain representative data on the population's body burden and the quality of their indoor environment and immediate surroundings. The present paper reports on cadmium levels in blood, urine and hair of 4021 adults aged 25-69 and 736 children aged 6-14. The statistical analysis included both descriptive and inferential methods. The data were classified according to social factors, lifestyle characteristics, and environmental exposures. Moreover, regression analysis was used to determine the predictors of cadmium concentrations in the types of sample studied. Active cigarette smoking was found to be dominant in affecting blood and urine cadmium levels in adults, but less important for cadmium levels in hair. Age and creatinine level in urine were additional important factors influencing the cadmium concentration in urine, especially in women. Environmental and occupational exposures to cadmium played only a minor role in the exposure models for German adults. The cadmium concentration in blood and urine was generally lower in children than in adults, while no significant difference for cadmium in hair could be detected. The cadmium concentrations in all three samples were significantly higher in East German children than in West German children.

Adolescent↗
PubMedDate not supplied

The German Environmental Survey 1990/1992 (GerES II): reference concentrations of selected environmental pollutants in blood, urine, hair, house dust, drinking water and indoor air.

The German Environmental Survey (GerES) is a large-scale, representative population study that has been carried out three times up to now with a time interval of about 7 years. GerES I was performed in 1985/1986, GerES IIa in 1990/1991 in West Germany, and GerES IIb in 1991/1992 in East Germany, the former German Democratic Republic (GDR). In GerES II, blood, urine, and scalp hair samples of 4021 adults aged 25-69 years and of 736 children aged 6-14 years were analysed as well as environmental samples (house dust, drinking water, indoor and personal air, diet). Characteristics of the frequency distributions of the substances analysed in the different media were calculated. The geometric mean (GM) for lead, cadmium, and mercury in the blood of adults amounted to 45.3, 0.36, and 0.51 microg/l, respectively. The corresponding values of arsenic, cadmium, and mercury in urine were 6.3, 0.29, and 0.54 microg/l, respectively. The concentrations of lead in blood, cadmium in blood and urine, and mercury in blood are lower in children than in adults. The GM ofpentachlorophenol (PCP) in urine of adults was 2.67 microg/l and in urine of children, 4.15 microg/l. These results of GerES II were compared with the so-called HBM values which represent health-based exposure guidelines and have been defined by the Human Biomonitoring Commission (HBC) of the Federal Environmental Agency, interalia for lead in blood, cadmium in urine, mercury in blood and urine, and PCP in urine. They also provided asound basis for the setting of reference values to describe the status of the German population. A total of 1.8% and 0.6% of the German females in child-bearing age had a level of lead in blood higher than HBM-I (100 microg/l) and HBM-II ( 150 microg/l), respectively. One percent of the children had a blood lead level above HBM-I. House dust and drinking water were analysed to characterise exposure in the domestic environment. Arsenic, cadmium, and lead deposition in homes amounted to 5.4 ng/(m2 day), 11.7 ng/(m2 day), and 0.29 microg/(m2 day), respectively. In the content of vacuum cleaner bags, concentrations were 2.1,0.9, and 5.9 microg/g. PCP, lindane and permethrin could be detected in the house dust of most German households. The pollutant load of the drinking water is significantly influenced by the corrosion of pipe materials and fittings. The new EC limit value of 10 microg/l for lead was exceeded in 7.7% of the first draw samples. The relatively high percentage (14%) of samples from East Germany that exceeded the current German guideline value for formaldehyde of 0.1 ppm in indoor air may be explained by the widespread use of contaminated particleboard in the former GDR.

Adolescent↗
PubMedDate not supplied

Keratin 9 mutations in the coil 1A region in epidermolytic palmoplantar keratoderma.

The palmoplantar keratodermas (PPK) are a heterogeneous group of conditions, most frequently inherited in autosomal dominant fashion. A few are well-documented autosomal recessive disorders; other are acquired in association with certain metabolic disorders and malignancies. Recently different point mutations of the keratin 9 (K9) gene have been identified in unrelated families with epidermolytic palmoplantar keratoderma (EPPK). We investigated two unrelated Hungarian families with EPPK. In one, a mutation consisting of a G-->A transversion at nucleotide position 551, which changes codon arginine to glutamine at codon 162 (R162Q), was found. In the other, we observed a novel mutation at nucleotide position 571, which changes codon 169 lysine (AAG) into the amber stop codon (TAG) (K169X). Each found mutation is present in the highly conserved coil 1A region of the rod domain. In the case of a stop codon type of mutation, it is questionable whether it really results in a clinical phenotype, but segregation analysis revealed cosegregation of the PPK phenotype with the mutant allele.

Adult↗
PubMedDate not supplied

[Methylphenidate double-blind trial: indication and performing].

Hyperkinetic disorders or attention-deficit/hyperactivity disorders (ADHD) are among the psychiatric diagnoses most often encountered in children and adolescents. Symptoms include inattention, hyperactivity and impulsivity. Within the multi-modal treatment system, the therapy with psychostimulants (e. g. methylphenidate) proved to be an effective in patients with ADHD. A double-blind trial is indicated in cases of unclear efficacy of methylphenidate at initial application or if psychostimulants have regularly been applied for more than one year with an leave-out trial delivering unequivocal results. Further it is helpful in verifying potential undesirable side effects and improving patients' compliance.

Adolescent↗
PubMedDate not supplied

Susceptibility of enamel surfaces to demineralization after application of fluoridated carbamide peroxide gels.

The aim of the present study was to evaluate the effect of experimental, fluoridated carbamide peroxide gels on formation of erosively induced demineralization of enamel. Seventy-five bovine enamel specimens were polished for microhardness determination and evenly distributed among 5 groups (A-E). The specimens were treated with 10% carbamide peroxide gel (8 h) and subjected twice to remineralization for 2 h in artificial saliva and demineralisation for 90 s in 1% citric acid, pH 2.2. The cycles of treatment with carbamide peroxide and twofold re- and demineralization were repeated three times. The carbamide peroxide gels were different in pH and fluoride content. Gel A (pH 7.0) and gel B (pH 5.7) were fluoridated (0.5% F), gel C (pH 7.0) and gel D (pH 5.7) were not fluoridated. In control group E the samples were not treated with a gel, but stored in 100% humidity for 8 h instead. Knoop microhardness of the specimens was assessed directly after polishing, and after each carbamide peroxide treatment and demineralization. All specimens showed a loss of microhardness at the end of the experiment. After 3 days, the controls revealed a significantly lower hardness loss compared to the specimens treated with the carbamide peroxide gels. Surface softening was significantly lower for the specimens of group A compared to the remaining groups (B-D), which were not significantly different among each other. It is concluded that treatment with either fluoridated or unfluoridated carbamide peroxide gels, at either neutral and acidic pH, renders enamel more susceptible to demineralization. Use of a fluoridated neutral gel decreases the degree of surface softening compared to the other gels investigated.

Analysis of Variance↗
PubMedDate not supplied

Brushing abrasion of softened and remineralised dentin: an in situ study.

The aim of the present in situ study was to evaluate the effect of different periods of intra-oral remineralisation on the susceptibility of softened dentin to toothbrushing abrasion. Groups of 6 human dentin specimens (A-F) were recessed in the buccal aspects of intra-oral appliances which were worn for 21 days by 11 volunteers. The samples were demineralised twice a day extra-orally in the acidic beverage Sprite Light (pH 2.9) for 90 s. Subsequently, the dentin specimens were brushed at different times. Specimen A was brushed immediately after demineralisation. Specimens B-E were brushed after the intra-oral appliances had been worn for various periods in the mouth: specimen B for 10 min, C for 20 min, D for 30 min and E for 60 min. Specimen F was not brushed (control). After 21 days, dentin wear was measured with a profilometer. The following values (means +/- standard deviation) were recorded (microm): A, 23.6 +/- 16.7; B, 37.9 +/- 29.7; C, 31.8 +/- 26.5; D, 18.5 +/- 10.5; E, 15.3 +/- 11.6; F, 12.6 +/- 6.7. There was a statistically significantly increased dentin loss for groups A, B and C as compared to the controls (U test: p < 0.05). However, after intra-oral periods of 30 and 60 min, wear was not significantly higher than in unbrushed controls. It is concluded that for protection of dentin surfaces at least 30 min should elapse before toothbrushing after an erosive attack.

Carbonated Beverages↗
PubMedDate not supplied

Method to detect minimal amounts of calcium dissolved in acidic solutions.

The study describes the application of the Arsenazo III method for detection of minimal amounts of calcium 12.4-49.4 micromol/l in different acidic solutions (hydrochloric acid, oxalic acid, maleic acid, phosphoric acid, tartaric acid, citric acid, lactic acid and acetic acid) adjusted to pH 2.0, 2.3 and 3.0. A mixture of the respective calcium concentrations with distilled water served as control. The experiments were run with ten repeats in series. Assessment of intra- and interassay coefficient of variation, and lower limit of quantification revealed that depending on the acid used, the Arsenazo III method is a reliable tool to quantify minimal calcium contents in acidic solutions.

Arsenazo III↗
PubMedDate not supplied

Plasma neurotensin: lack of a differentiation and tumor marker in children with neuroblastoma.

Neurotensin is a tridecapeptide with changing receptor expression in central and peripheral neural cells during ontogeny suggesting its potential use as a differentiation and tumor marker in neuroectodermal malignancies. We investigated the neurotensin levels in plasma samples of 58 patients with neuroblastoma using a sensitive radioimmunoassay. Elevated levels were found only in one stage III and in one stage IVs patient, while the neurotensin concentrations of 56 patients were in the range of control children. We conclude that plasma neurotensin reflects neither the differentiation nor the tumor status in children with neuroblastoma.

Biomarkers, Tumor↗
PubMedDate not supplied

Ovarian remnant syndrome: revascularization of free-floating ovarian tissue in the feline abdominal cavity.

Nine, healthy, intact female domestic shorthair cats were ovariohysterectomized. At the time of surgery and following removal, the major portion of one ovary was loosely sutured to the mesentery and replaced in the abdominal cavity. Six months later, an abdominal laparotomy was performed in order to retrieve the ovarian remnants. Histopathological examination of the remnants showed viable tissue and evidence of ovarian follicles or corpora lutea in eight of nine (88.9%) cats. The ninth ovarian remnant was atrophied and fibrotic. Measurement of serum estradiol and progesterone, vaginal cytology, and stimulation of estrus and ovulation with a protocol using pregnant mare serum gonadotropin (PMSG) followed by human chorionic gonadotropin (hCG) were unreliable indicators of ovarian activity in this study. Revitalization of an ovarian remnant was shown to occur in the absence of surgical implantation.

Animals↗
PubMedDate not supplied

Falsification of tetrazolium dye (MTT) based cytotoxicity assay results due to mycoplasma contamination of cell cultures.

Mycoplasma contamination of cell cultures is a frequently observed problem. Due to the inconspicuous growth in cell cultures, periodical screening procedures represent the only protection. Many influences of mycoplasma on cell culture parameters have been described. We addressed the question of whether mycoplasma contamination affects the most frequently used cytotoxicity assay, the tetrazolium based MTT assay. We contaminated C6 glioma cells with mycoplasma and performed MTT assays with doxorubicin, vincristine, etoposide and cisplatinum under various conditions. Contaminated cells demonstrated significant different results when tested with the MTT assay than mycoplasma free controls. Differences were not detectable when cells were counted as toxicity assay. Due to an additional reduction of tetrazolium by mycoplasmas, contaminated cells appeared up to 15 fold resistant to doxorubicin, vincristine and etoposide, but not to cisplatinum. Differences decreased with decreasing drug doses and decreasing plated cell count. Our findings confirm the compelling need for periodical mycoplasma screening, especially when tetrazolium based cytotoxicity assay (MTT) are used.

Animals↗
PubMedDate not supplied

Individual fecal alpha 1-antitrypsin excretion reflects clinical activity in Crohn's disease but not in ulcerative colitis.

BACKGROUND/AIMS: The natural course of fecal alpha 1-antitrypsin (AAT) excretion was assessed in patients with inflammatory bowel disease (IBD) to evaluate its role in monitoring their clinical disease activity. METHODOLOGY: A prospective cohort pilot study was performed in 9 patients with Crohn's disease (CD) and 3 individuals with ulcerative colitis (UC). Subjects were investigated at regular monthly intervals for about one year for (a) parallel AAT stool and serum concentrations by standard immunonephelometry, and (b) for clinical disease activity by Crohn's Disease Activity Index (CDAI) in CD patients, and by Clinical Activity Index (CAI) in UC subjects. Absolute results during follow-up were each referred to individual findings at study entry as relative results. RESULTS: While absolute fecal AAT concentration did not correlate with disease activity indices (p > 0.26), relative fecal AAT concentration significantly correlated to concurrent relative CDAI score in CD patients (p < 0.001, r = 0.67), but not to relative CAI score in UC subjects (p = 0.92). Monthly intraindividual variation of fecal AAT excretion did not predict development of either disease activity index (p > 0.14). CONCLUSIONS: Individual fecal AAT excretion closely reflects clinical course in CD subjects, but not in UC patients. It does not predict symptomatic deterioration in these individuals, at least on a short-term basis.

Adult↗
PubMedDate not supplied

Costello syndrome with decreased glucose tolerance.

We report a case of Costello syndrome, which is an uncommon multisystemic condition with cutaneous manifestations on the palms and soles. In the literature there are 29 cases described, all the studies are published in the genetic literature with a few exceptions. We add a further case associated with impaired glucose tolerance. The diagnostic clinical signs are impressive, and highly characteristic. Cutaneous manifestations are: loose skin of the hands and feet "washer woman's hand", hyperkeratosis palmoplantaris, curly or sparse hair, acanthosis nigricans, papillomata nasi. Coarse, progeroid facial features with a bulbous nose, feeding difficulties in infancy, cardiac involvement with cardiomyopathy or conduction defect, and in our case impaired glucose tolerance also presented. Postnatal growth retardation, mental retardation, and a distinctive friendly personality is characteristic. Hyperextensible fingers with broad distal phalanges and joint contractures were observed, and peroneal hypertonicity required treatment by Achilles tendon lengthening. The decreased glucose tolerance is interesting in the view of the acanthosis nigricans. No storage disease and no chromosomal abnormality were observed. Only in one case is a balanced translocation described in the literature.

Abnormalities, Multiple↗