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Biomedical subjects

T Fischer

Publications and source records attributed to T Fischer.

At least 199 records · Page 11Linked to original sources
PubMed1994

Lead exposure in starter battery production: investigation of the correlation between air lead and blood lead levels.

The threshold limit value (TLV) for lead (in Germany, the MAK value) is based on a certain blood lead concentration (in Germany BAT value = biological tolerance value for working materials) that is not to be exceeded; thereby a statistically significant association between air lead (PbA) and blood lead (PbB) is assumed. On the basis of a 10-year period of (1982-1991) biological and ambient monitoring of 134 battery factory staff and their workplaces, a PbA/PbB correlation with the regression equation PbB = 62.183 + 21.242 x Log 10 (PbA) (n = 1089, r = 0.274, P < 0.001) was calculated. These results are in line with those of several other investigations. The shape of the regression curve and the wide scattering of values led to the assumption that PbA values above the MAK value (0.1 mg/m3) do not necessarily result in increased PbB values. Similarly, PbA values lower than the MAK value do not guarantee PbB levels below the BAT value in every case. These observations are influenced by numerous confounders and intervening variables. It is concluded that lowering MAK values as a consequence of lowering BAT values is not mandatory.

Air↗
PubMed1994

Plasma concentration of elastase-alpha 1-proteinase inhibitor complex in surfactant-treated preterm neonates with respiratory distress syndrome.

Although exogenous surfactant replacement improves respiratory distress syndrome (RDS) of immature neonates, it may not prevent subsequent lung damage and development of bronchopulmonary dysplasia associated with polymorphonuclear neutrophil (PMN)-activation. We therefore wanted to assess whether surfactant administration would be associated with activation of circulating PMNs. Since elastase-alpha 1-proteinase inhibitor (E-alpha 1-PI) has proved to be a sensitive indicator of intravascular PMN activation, we studied E-alpha 1-PI plasma concentration in preterm neonates during the treatment of RDS with a bovine surfactant preparation (group I: n = 23). Results were compared with those from a retrospective control group treated by ventilation alone (group II: n = 13), and with a reference group of 92 newborns (group III). Following surfactant administration, median E-alpha 1-PI concentration increased significantly (day 1 80.5 vs Day 2,234 micrograms.l-1), and exceeded the upper limit of the reference range of 274 micrograms.l-1 in seven patients, with a maximal value of 1,881 micrograms.l-1 after multiple surfactant administrations. In contrast, 12 infants from Group II showed no increase in median E-alpha 1-PI levels (Day 1,107 vs Day 2,107 micrograms.l-1), and remained within the reference range (Day 1,125 micrograms.l-1; Day 2,107 micrograms.l-1) of the 92 newborns without respiratory impairment, infection, birth-trauma or asphyxia. From these results, it is concluded that surfactant may trigger a transient, mainly local, inflammatory response, reflected by increased levels of E-alpha 1-PI, and may exert a dose-related pathogenic influence on the course and prognosis of RDS.(ABSTRACT TRUNCATED AT 250 WORDS)

Bronchopulmonary Dysplasia↗
PubMed1994

[Breech presentation--information, anxiety and expectations of established obstetricians and pregnant patients. 1: Results of a survey of established obstetricians].

In a anonymous questionnaire we studied the advise of gynecologists to breech presented pregnant women in the area around Nürnberg-Fürth-Erlangen in Germany. 61.5% of gynecologists participated the study, 71.2% of them (n = 57) prefer primary caesarean section in primapara. 13.8% (n = 11) of the questioned doctors favour a vaginally delivery procedure. Advise to multiparas for primarous caesarean section was given in 8.8% (n = 7) and for vaginally delivery mode in 80.0% (n = 64). Reasons for caesarean section was a decreased fetal delivery risk (90%, n = 72) and the possibility of prospective delivery planing (26.3%, n = 21). Other reasons were various obstetrical risk factors and forensic aspects. Benefits of vaginally delivery mode in multiparas was a low fetal delivery risk (72.5%, n = 58) and a low maternal morbidity (66.3%, n = 53). Results of actual studies are suggesting, that there is a controlled fetal risk of vaginally delivery mode in breech presented labour. According to these studies a change of labour procedure is essential.

Attitude of Health Personnel↗
PubMed1993

The mechanism of inhibition of alkylamines on the mast-cell peptidergic pathway.

GTP-binding proteins are known to play an important role in controlling mast-cell exocytosis and are described as the primary targets of peptidic mast-cell histamine releasers. The mechanism of inhibition of the mast-cell peptidergic pathway by alkylamines, which are selective inhibitors of this pathway, was investigated using intact or permeabilized rat peritoneal mast cells. Histamine release induced by GTP gamma S and by mastoparan (a venom peptide activating G proteins) was inhibited by pretreating mast cells with 0.1 to 3 micrograms/ml of a mixture of benzalkonium chloride containing in majority a twelve-carbon-atom aliphatic chain (BAC(C approximately 12)). Pure benzalkonium chloride, with a fourteen-carbon-atom aliphatic chain (BAC (C14)), at 5 to 10 microM also inhibited histamine release induced by GTP gamma S and mastoparan. The dose-response curve of mastoparan-induced histamine release from intact mast cells was shifted to the right by various concentrations of BAC (C14). Similar results were obtained with another alkylamine differing from BAC (C14) by the absence of the benzene ring, tetradecyltrimethylammonium bromide, TAB (C14). This illustrates that the presence of the phenyl radical is not required for the inhibitory effect of benzalkonium chloride. BAC (C approximately 12) and BAC (C14) inhibited the generation of inositol polyphosphates induced by GTP gamma S. BAC (C approximately 12) and TAB (C14) inhibited the mastoparan-stimulated GTPase activity from mast-cell Gi-like proteins. These results suggest that alkylamines exert selectively their inhibitory effect via an interaction with mast-cell Gi-like proteins coupled to phospholipase C, i.e., at an early stage in the stimulus-secretion coupling process.

Benzalkonium Compounds↗
PubMed1993

Absence of specific IgE antibodies in allergic contact sensitivity to formaldehyde.

Immunologic reactions are customarily divided into two broad categories, cell-mediated and antibody-mediated. An interplay between these two pathogenetic principles is indicated by reactions such as cutaneous basophil hypersensitivity, late-phase reaction, and cutaneous lesions indistinguishable from regular allergic contact dermatitis lesions after sensitization with IgE antibodies against certain haptens. In the present study, 23 patients with a history of a positive epicutaneous test to formaldehyde participated. On retest, 15 showed a positive reaction. Eight patients were Phadiatop positive, indicating an atopic diathesis, and eight had a history of or ongoing atopic dermatitis. On RAST test, only two, nonatopic patients had specific IgE antibodies to formaldehyde. In the cellular infiltrates of biopsies from epicutaneous test sites, cells reactive with monoclonal antibodies against IgE were found in positive and negative formalin tests, both in atopics and nonatopics, as well as in control biopsies from nonlesional skin. Double immunofluorescence staining experiments showed that IgE occurred on Langerhans' cells. The proportion of IgE-positive cells correlated to the level of serum IgE, but not to atopy. These cells were also found both in the epidermis and in the dermis in nonatopic patients. ICAM-1 occurred on keratinocytes in all patient groups. This study does not support the hypothesis that specific IgE antibodies are active in the pathogenesis of contact sensitivity to formaldehyde either in atopic or in nonatopic patients.

Biopsy↗
PubMed1993

[Methodological-didactic concepts in the occupational rehabilitation of adults in Phase II facilities?].

While specific methods from disabled and special education didactics are available for young people, pertinent didactical concepts and experience are lacking in case of adults, in particular for rehabilitees with chronic mental illness and brain damage. Further education schemes have hence been started in 1989 within the Federal working group of medical-vocational (phase II) facilities, focussing on appropriate learning strategies and on rooting them in the minds of educators and teachers. Oriented along the "Berlin didactical model", Stadler's approach is considered fundamental in developing a didactical concept for adults with disabilities. Practical suggestions and hints at existing, proven methodical strategies are used to help illustrate concrete possibilities for systematically gearing time-tested methodical strategies to disability-generated learning problems. An almost synchronous development, similar learning strategies are to be found in industrial and occupational didactics as well, under a "holistic education" and "enhancement of key qualifications" heading. Participant orientation as the fundamental principle of a "disability-specific" methodology, holistic didactic concepts, a fitting learning organization, application of project-, activity- and experience-based methods, fitting problem-solving techniques, as well as a reconsideration of current teaching principles, are in the foreground of the present contribution.

Adult↗
PubMed1993

[Induction of the atrial and ventricular ANF synthesis in experimental heart failure after aortocaval shunt].

Using the aortocaval shunt as a model of chronic volume overload in the rat, changes of the ANF system were analyzed. A constant shunt volume of 57% increased the heart weight after 14 days by 28% (from 917 +/- 16 to 1177 +/- 28 mg, p < 0.001). The ANF plasma concentration increased from 30.4 +/- 15.1 to 108.2 +/- 30.6 pg/ml (p < 0.05), which corresponds to levels which are reached in early stages of heart failure. ANF tissue concentrations, however, were decreased in both atria while no significant change could be observed in the ventricles. The analysis of the ANF-mRNA expression as an indicator for the ANF-synthesis showed significant increase in the ANF-mRNA/Actin-mRNA ratio in the right atrium by 56% and in the left atrium by 63%. In ventricular tissue the relative ANF-mRNA increased by 58% (right) and 83% (left ventricle). Increased ANF plasma levels during chronic volume overload are due to increased atrial and ventricular ANF-synthesis. The induced ventricular mRNA indicates the participation of the ventricles in the humoral response to volume overload.

Animals↗
PubMed1992

The use of FK506 and RS61443 for reversal of small-bowel rejection.

Successful clinical small-bowel transplantation is still difficult to achieve. Two features render the small intestine unique among vascularised solid organ grafts. First, the bowel contains a large amount of lymphoid tissue within the Peyer's patches, mesenteric lymph nodes, and intraepithelial lymphocytes, which are thought to mediate graft-versus-host disease and provide a major stimulus for the recipient's immune system. Unfortunately, mere surgical reduction of these tissues, by using segmental allografts, does not furnish any immunological advantage. Second, the small bowel lacks specific serum markers such as blood urea nitrogen (BUN) in the kidney or bilirubin in liver transplantation. Clinical signs such as fever, pain, or tenderness of the abdomen may indicate an already advanced destruction of the graft. Therefore, very potent immunosuppressive regimens are necessary to avoid small-bowel allograft rejection or even to reverse an ongoing rejection process. Cyclosporin was shown in small and large animal models to control rejection reactions sufficiently. However, there are two even more promising immunosuppressive agents currently under investigation. FK506, a macrolide lactone isolated from Streptomyces tsukubaensis, leads to long-term survival of small-bowel allografts in a rodent model and has already been used in a few clinical small-bowel transplantations. RS61443, a mycophenolic acid morpholinoethylester, selectively inhibits T- and B-cell proliferation. We have investigated the use of FK506 and RS61443 for the reversal of small-bowel allograft rejection in a small animal model.

Animals↗
PubMed1992

Spontaneous echo contrast imaging in infective endocarditis: a predictor of complications?

Infective endocarditis is associated with significant morbidity and mortality. Valvular destruction and congestive heart failure are more common in patients with echocardiographically detectable vegetations. In addition, spontaneous platelet aggregation is increased when vegetations are present on cardiac valves. The aim of the study was to assess the prognostic value of spontaneous echo contrast (SEC) imaging, as SEC is supposed to reflect red blood cell aggregates stimulated by platelet activity. We studied 293 patients with clinical signs of infective endocarditis. Vegetations, attached to the aortic or mitral valve, were found in 130 patients (44.4%) who were followed for a mean period of 12 months. In 34 of these 130 patients (26.2%) SEC was imaged during the initial transesophageal echocardiographic examination. In these patients SEC indicated a prolonged healing of infective endocarditis with a specificity of 91.2%, a sensitivity of 77.3%, a positive accuracy of 77.3%, a negative accuracy of 74.3%. Multivariate analysis revealed that SEC is a risk factor for valve replacement (p less than 0.001) and for embolic events (p less than 0.001), less for mortality (p less than 0.01), and lowest for abscess formation (p less than 0.05). The dose of ADP to induce half-maximal platelet aggregation was significantly lower in patients with SEC (0.71 +/- 0.15 microliters) than without SEC (1.05 +/- 0.12 microliters; p less than 0.05), implying an increased spontaneous platelet aggregation in the presence of SEC. Our data provide evidence that systemically activated coagulation plays an important role in infective endocarditis. SEC, the echocardiographic implication of an increased platelet aggregation, predicts complications such as thromboembolic events and the need for surgery and is closely related to the prolonged healing period of infective endocarditis. In addition to demonstrating vegetations, transesophageal echocardiography provides information helpful in assigning patients to a high-risk subgroup. Transesophageal echocardiography may play an important role in assessing the clinical outcome of these patients.

Adult↗
PubMed1992

Endocrine function in multiple sclerosis.

In 31 patients with multiple sclerosis (MS) the endocrine functions of the hypothalamus, the pituitary and several peripheral endocrine glands were assessed with a combined pituitary test; 3/31 patients had an endocrine disease: one primary hypothyroidism, one primary amenorrhea and one primary male hypogonadism. We found no patient with endocrine disease of the hypothalamus, the pituitary or the adrenals. However, the poststimulatory secretion of cortisol, growth hormone or thyroid-stimulating hormone was impaired in 7/31 patients, suggesting a possible preclinical endocrine insufficiency in these patients.

Adult↗
PubMed1992

The 93-kilodalton protein of Borrelia burgdorferi: an immunodominant protoplasmic cylinder antigen.

Using immunoblots, we identified proteins of Borrelia burgdorferi recognized by sera from 62 patients with either acute or chronic Lyme disease. In all groups studied, the 41-kDa flagellar protein and a relatively minor 93-kDa protein (p93) were the most commonly recognized antigens in patients with acute and chronic disease due to B. burgdorferi. A murine monoclonal antibody (MAb 181.1) was developed against p93, and the antigen was detected by immunoblot analysis in four European and American strains of B. burgdorferi. On two-dimensional gel electrophoresis, p93 had an apparent pI of 6.8. Immunoelectronmicroscopy with MAb 181.1 demonstrated that p93 is located within the protoplasmic cylinder compartment of the organism. The gene encoding p93 was retrieved from a phage expression library. The derived amino acid sequence of p93 confirmed chemical characterization of the antigen, including its amino-terminal peptide sequence. The derived amino acid sequence predicted it to be predominantly alpha helical. A prominent antigenic domain located at the carboxy portion of the protein was recognized by human and rabbit polyclonal antisera and human (MAb D4) and mouse (MAb 181.1) MAbs.

Amino Acid Sequence↗
PubMed1992

PUVA: how to use it for maintenance.

The selection of optimal maintenance therapy for psoriasis needs great dermatologic skill. The choice between topical therapy, photochemotherapy (PUVA), UVB, and immunomodulating regimens alone or in combinations is a balance between cost and benefit. The effectiveness of healing and the tendency to relapse stands against convenience and access of therapy, the patients' motivation, and not least, the risks of side effects. The effective PUVA-maintenance must be reserved for patients who do not experience clearing of their disease on mild topical and UVB regimens.

Combined Modality Therapy↗
PubMed1991

[Malignant lymphoma associated with HIV infection].

The course of disease in 119 HIV-infected patients (117 men, 2 women; median age 38.5 years) with malignant tumours other than Kaposi's sarcoma was analyzed in a multi-centre retrospective study. This was conducted to obtain initial information concerning the incidence, clinical features and results of therapy in HIV-associated neoplasms, especially malignant lymphomas. The most frequent tumour was malignant non-Hodgkin's lymphoma (98 patients, 82.5%), seven patients had Hodgkin's disease, five had solid tumours, four a polyclonal lymphoproliferative syndrome, three an acute lymphocytic leukaemia, and two had other lymphoproliferative diseases. 58% of the non-Hodgkin's lymphomas occurred in patients with marked immunodeficiency, 85% were high grade malignancies and 47% had primary extranodal disease. 56% of primary nodal lymphomas also had visceral spread (Stage IV). Lymphoblastic non-Hodgkin's lymphoma was more common in patients with favourable immunological status, presented less frequently with primary extranodal disease, was diagnosed earlier than other non-Hodgkin's lymphomas, and appeared to carry a better prognosis. 78 out of the 98 patients with non-Hodgkin's lymphoma had been treated, 66 with cytotoxics. The median survival time was 6 months. Longer remission periods, of at least 12 months, were seen in ten of the 78 patients (13%). Despite the overall poor prognosis and the pre-existing immune defect, palliative (chemo-)therapeutic measures are both justified and promising, and may also result in life-prolonging remissions.

Adult↗
PubMed1991

Modulation of coronary circulation and the cardiac matrix by the renin-angiotensin system.

There are short-term and long-term modulations of cardiac function and cardiac composition by the endocrine and paracrine renin-angiotensin system. First, there is an enhancement of coronary vasoconstrictor tone in severe congestive heart failure due to stimulation of this system. Therapeutic interventions that block the RA-system are able to reduce the increased resistance to coronary flow. Second, there is a relationship between the occurrence of arrhythmias and the degree of sympathetic stimulation in congestive heart failure. The renin-angiotensin system may be involved in arrhythmogenesis because of presynaptic modulation of sympathetic neurotransmitter release. However, in the isolated perfused rat heart no class-specific antiarrhythmic properties could be found for ACE inhibitors during progressive myocardial ischaemia. Third, proliferation of the neointima following injury of a coronary artery is at least in part mediated by angiotensin II. Although ACE inhibition was an effective tool in animal experiments to prevent excessive proliferation of the neointima following ballooning, it was less effective in preventing restenosis in man following a repeat coronary angioplasty. Fourth, preferential proliferation of the cardiac interstitium in experimental hypertension has been associated with activation of the renin-angiotensin system. In patients with essential hypertension ACE inhibitors were not only capable of controlling blood pressure but also of normalizing the previously pathological pattern of diastolic left ventricular filling. In summary, by therapeutic intervention that cause a blockade of this system, cardioprotective and cardioreparative processes can be supported.

Angiotensin II↗