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Biomedical subjects

E Richter

Publications and source records attributed to E Richter.

At least 145 records · Page 8Linked to original sources
PubMed1994

Biomonitoring of hemoglobin adducts: aromatic amines and tobacco-specific nitrosamines.

A new analytical procedure has been developed for the simultaneous determination of human hemoglobin adducts from aromatic amines and tobacco-specific nitrosamines. These tobacco-related hemoglobin adducts were determined in nonsmokers, smokers, and users of nasal snuff. Adducts from aminobiphenyl compounds are good biomarkers of exposure to tobacco smoke; they are not elevated in users of nasal snuff. However, a significant contribution of environmental exposure to aromatic amines and/or the corresponding nitroaromatics makes it difficult to evaluate passive exposure to tobacco smoke. The best biomarkers for exposure to tobacco smoke should in theory be adducts arising from tobacco-specific nitrosamines. The common adduct from N'-nitrosonornicotine and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone releases 4-hydroxy-1-(3-pyridyl)-1-butanone from hemoglobin upon mild alkaline hydrolysis and only marginal differences are found in the adduct level in smokers and nonsmokers. The reason for this observation is not yet understood and is currently under investigation. However, the adduct formed by tobacco-specific nitrosamines is well suited for the detection of oral and nasal tobacco use. Only by simultaneous determination of both adducts formed by aromatic amines and tobacco-specific nitrosamines is it possible to differentiate between nonsmokers, smokers, and nasal snuff users.

Aminobiphenyl Compounds↗
PubMed1994

Metabolism of a glucuronide conjugate of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone in rats.

Besides 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), [4-(methylnitrosamino)-1-(3-pyridyl)butl-yl]-beta-O-d-glucosidu ronic acid (NNAL-Glu) is another important metabolite of the tobacco-specific nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) which has been detected in the urine of tobacco users and non-smokers heavily exposed to sidestream cigarette smoke. In order to evaluate the toxicological significance of NNAL-Glu formation and excretion, the metabolism of [5-3H]-NNAL-Glu was studied in rats. Five male F344 rats were administered 3.7 mg/kg [5-3H]-NNAL-Glu by i.v. injection and the metabolites in urine analysed by HPLC. More than 90% of the radioactivity was excreted in urine within the first 24 h. Unchanged NNAL-Glu accounted for 81.2 +/- 3.1% of the total radioactivity; the remaining part of the dose appears to be deconjugated resulting in the urinary excretion of NNAL (3.6 +/- 1.7%) and its alpha-hydroxylation (11.5 +/- 2.2%) and N-oxidation (3.6 +/- 1.6%) products. The presence of alpha-hydroxylation products of NNAL-Glu in urine suggests that this NNK metabolite may be activated in vivo to carcinogenic intermediates.

Animals↗
PubMed1994

Detection of Mycobacterium leprae by three-primer PCR.

Recently, polymerase chain reaction has been introduced for the species-specific assessment of Mycobacterium leprae (1). To avoid Southern blotting techniques using radioactively labelled oligonucleotide probes, the aim of this study was to establish a three primer-based single-step PCR technique. Using primers designed for this purpose we amplified a part of the gene encoding for the 16S ribosomal RNA of slowly growing mycobacteria. Due to the species-specific antisense primer a second, smaller fragment specific for M. leprae was amplified. Our results show that the employment of a second antisense primer in the PCR may be a substitution for Southern blot hybridization.

Base Sequence↗
PubMed1994

Mycobacterium leprae DNA content, cellular and cytokine patterns in skin lesions of leprosy patients undergoing multidrug therapy (MDT).

Skin biopsies from untreated and MDT-treated patients were examined for infiltrating cells and cells producing the cytokines TNF-alpha, IFN-gamma, and IL-1 beta using immunohistochemistry. Biopsy specimens from untreated tuberculoid leprosy patients were characterized by the presence of cells producing TNF-alpha, IFN-gamma, and IL-1 beta and of subepidermal Langerhans cells. These cells were rarely found or completely absent in biopsies of untreated lepromatous leprosy patients, but tended to increase under MDT. In a short-term therapy trial for three months with brodimoprim, dapsone, and rifampicin, 12 patients were monitored by follow-up biopsies. Semiquantitative PCR for mycobacterial DNA revealed two groups of patients: one group in which mycobacterial DNA in follow-up biopsies remained constant and a second group in which a decrease of mycobacterial DNA during therapy was noted. Immunophenotyping in these follow-up biopsies revealed that in the latter group IFN-gamma-positive cells and Langerhans cells were present and gamma delta T cell receptor-positive cells tended to decrease during therapy. In contrast, in patients whose mycobacterial DNA did not change during therapy, these phenotypical manifestations were not observed. We therefore, conclude that assessment of mycobacterial DNA in combination with phenotyping of infiltrating cells and determination of cytokine patterns may be useful tools in establishing criteria for the effectiveness and duration of MDT in patients with leprosy.

Anti-Bacterial Agents↗
PubMed1994

[Long-term results of stapes surgery with the Schuknecht wire-teflon prosthesis].

Early and late postoperative findings in 78 cases of stapedial surgery with 0.6 mm Schuknecht Teflon Wire Pistons only, performed from 1983 to 1987, were analysed to evaluate the supposition of an inverse relationship of the size of the footplate fenestration and functional long-term results. In respect of the size of fenestration our surgical strategy resulted in 3 different situations: stapedotomy (26)--partial platinectomy (34)--stapedectomy (19). Mean air conduction thresholds for frequencies 0.5-4 kHz were evaluated preoperatively, one month and > 5 years postoperatively. The results were postoperatively significantly better in all 3 groups without significant intergroup differences. > 5 years postoperatively the best results were seen in the partial platinectomy group better than after stapedotomy and significantly better than in the stapedectomy group. With regard to overclosure, closure of the air bone gap and deterioration of bone conduction thresholds at 4 kHz for the same groups, no significant differences were noticed. In conclusion, the best long-term results were obtained after partial platinectomy, i.e. there was no inverse relation of the size of the footplate perforation and the best results. The perforation should be large enough to prevent tilting of the piston at the edge. Removal of larger parts should be omitted. In case of early mobilisation and stapedectomy good long-term results can still be expected.

Auditory Threshold↗
PubMed1994

Nicotine inhibits the metabolic activation of the tobacco-specific nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone in rats.

The effect of nicotine on the metabolism of the tobacco-specific nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) was studied in rats. [1-14C]NNK was s.c. injected at a dose of 0.08 mumol/kg. Co-administration of a 500-fold higher dose of nicotine (40 mumol/kg) did not reduce the overall urinary excretion of radioactivity. However, the metabolic pattern in 24 h urine was significantly changed. Metabolites resulting from NNK activation by alpha-hydroxylation were significantly (P < 0.001) reduced to 72% of the control. Detoxification to N-oxides and the glucuronide of 4-(methyl-nitrosamino)-1-(3-pyridyl)-1-butanol increased to 155% (P < 0.01) and 188% (P < 0.01) of the control respectively. These results suggest that nicotine, which occurs in concentrations up to 30,000-fold higher than NNK in mainstream smoke of cigarettes may have a protective effect against metabolic activation of NNK.

Animals↗
PubMed1994

Visualization of neonatal anatomy and pathology with a new computerized three-dimensional model as a basis for teaching, diagnosis and therapy.

A new computerized three-dimensional (3D) volume model derived from a post-mortem MRI series of the chest and abdomen of a human newborn allows interactive dissection by removing, adding organs or cutting in unlimited directions. The advanced technique of real volume visualization instead of using contours allows one to study the normal and pathological anatomy of the neonate. Anatomical details of the pleural, pericardial and peritoneal cavities and of abdominal veins are demonstrated. Compared to conventional methods, the advantages of this model for teaching and as a basis for diagnostic imaging and therapeutic procedures are evident.

Abdomen↗
PubMed1994

Asthma in Gaza refugee camp children and its relationship with house dust mites.

Three hundred asthmatic children aged 3 to 15 years, and 100 age-sex-neighborhood matched controls, were studied for environmental risk factors for asthma during 1986 to 1987. In 98% of the asthmatic patients, exposure to house dust aggravated the symptoms. In 97% of the cases, the symptoms were more severe at home; in more than 50%, the symptoms persisted throughout the year. Significantly more cigarettes were smoked in the homes of the allergic children than in the control homes. House dust samples from homes of 20 asthmatic and 20 nonasthmatic children were examined for the presence of house dust mites. Twelve species of mites were identified, of which Dermatophagoides pteronyssinus, the most prevalent (97%), was found in all samples examined. The average number of mites per gram dust was 447 in homes of children with asthma, and 399 in homes of controls. Although dust and mites seem to be the most important factors causing allergies in Gaza and most of the children are exposed to large numbers of mites in their homes, it appears that those who are genetically predisposed and who are exposed to environmental tobacco smoke are at greater risk for allergic symptoms.

Adolescent↗
PubMed1994

[In-line-filtration of erythrocyte concentrates using the Sepacell Integra System].

Using the Sepacell Integra System for in-line filtration of red cell concentrates in additive solution the leukocyte depletion was efficient enough to keep leukocyte contamination below the critical immunogenic load for leukocytes (CILL). The data indicate improved storage conditions, made evident by significantly lower cell damage.

Cytapheresis↗
PubMed1994

[4-Log leukocyte depletion of erythrocyte concentrates--a comparison with 3 other filters].

Whole blood (WB) and SAGM-resuspended red cell concentrates (RCC) were leucocyte-depleted 1 h after donation by filtration using BF 4 (PALL), Sepacell RS 200 (Asahi Med.) and Bio R01 Plus (Biotrans). We compared the handling of the filter system, focusing routine blood bank practice, filtration efficiency [residual white cell count; flow cytometry (Ortho Cytoron) and Nageotte chamber] and the loss of red cells. Spontaneous filling was found to be an advantage of the Bio R01 Plus system, whereas the BPF 4 and the RS 200 have to be filled by pressure. The filtrations were of similar duration, even those of WB and resuspended RCC. Red cell loss was found to be 10-15% on RCC higher than on WB (7-10%) and varied between the filters used: BPF 4 < Bio R01 Plus < RS 200. The residual white cell count on WB was 1.2-5.8 x 10(6) (RS 200 < Bio R01 Plus < BPF 4) and on RCC was 0.5-3.0 x 10(5) (RS 200 < BPF 4 < Bio R01 Plus). The filters used are highly effective (4-log depletion on RCC) even on fresh WB and are therefore potential in-line filters.

Blood Donors↗
PubMed1994

[In-line-filtration of erythrocyte concentrates using the Leukotrap-RC system].

'In-line filtration' was performed on whole blood (WB) of 12 healthy donors. The WB was drawn into the triple-bag Leukotrap-RC system. Six red cell concentrates (RCC) were filtrated 1 h after donation either with or without buffy-coat and stored 35 days in AS-3. We measured the loss of red cells, the residual white cell count (Nageotte chamber), platelet count in fresh frozen plasma (FFP); 2,3-DPG, K+, Hbe, pH, O2Hb and pO50. The system was easy to handle but needed circular centrifugation holders because the filter is placed and fixed just at the top of the bags during centrifugation. RCC without buffy coat led to a faster filtration (15 vs, 38 min) and to an improved FFP quality (platelet count 23 vs, 54 Gpt/l). The leucocyte removal rate of the integrated PALL-RC-350 was similar, residual white cell count less than 3 x 10(6), in both preparations. All storage parameters were found within the normal range except a significant increase of O2Hb in filtrated red cells compared with the unfiltered control.

Blood Donors↗
PubMed1994

[Metabolic and rheologic changes in long-term hypothermia of erythrocyte concentrates over 15 weeks].

With a multiple washing procedure in a chloride ion-free citrate-phosphate-glucose-adenine additive solution or with storage of red blood cells in a large volume of this solution, erythrocytes can be stored for 15 weeks at 4 degrees C. After 12 weeks' storage in this chloride-free solution the red blood cell parameters (2,3-DPG, glucose, lactose) measured are as good as stored erythrocytes resuspended in SAG-Mannitol after 21 days. Rheological parameters (morphology, filterability) show a maintenance of deformability of such preserved cells up to 84 days of storage. The preservation of erythrocytes by this method has the advantage that beside the hypothermic long-term storage (potential second aHIV screening of blood donors) the blood is of better quality in the first weeks of storage.

2,3-Diphosphoglycerate↗
PubMed1994

[Large volume lymphocytapheresis for the collection of peripheral stem cells].

We performed 29 large-volume leukaphereses of 20 patients for collection of peripheral blood stem cells. All patients have been pretreated with cytokines after chemotherapy. In 9 patients with precounts of > or = 3 x 10(9) mononuclear cells/l we achieved a sufficient transplantation doses with one LVL. If the MNC precount was < or = 3 x 10(9)/l we had to perform more than one LVL. On 16 patients we compared a standard apheresis procedure with the LVL procedure. It seems that especially patients with a lower MNC precount can profit from LVL. From patients with higher MNC precounts we harvested the double amount of MNCs, from patients with lower MNC precounts the triple amount.

Female↗