PubMed Health⌕ Search

Biomedical subjects

H Schroten

Publications and source records attributed to H Schroten.

At least 19 recordsLinked to original sources
PubMed2005

[The vaccination coverage among children aged 24 - 30 months in pediatric offices November 1999 - May 2001. The influence of socio-demographic characteristics].

BACKGROUND: The goal of this study was to investigate the influence of socio-demographic factors on vaccination coverage of 24-30 month old children in paediatric practices. METHODS: Vaccination coverage (VC) was documented for 15,682 children in 196 paediatric practices mainly in the region of Nordrhein. Data on socio-demographic factors were collected for 8,457 children and their influence on the vaccination status (VS) was investigated by means of logistic regression analysis. RESULTS: Complete age-appropriate VC for all vaccines recommended by the Standing Committee for Vaccination (STIKO) was 49.9 %. Complete VC for Diphtheria/Tetanus (DT) was 74.6 % and for first dose measles/mumps/rubella (MMR), 82.1 %. The following factors were associated with complete VS for DT and MMR: completion of last recommended well-child visit, parents living together, low number of siblings, short time to reach practice, parents stating they felt adequately informed about vaccinations. Complete vaccination for DT was inversely associated with being health insured through social security and for MMR with the mother having graduated from high school. CONCLUSIONS: A high proportion of 24-30 month old children did not have an age appropriate VS. Targeted parental education and timely vaccination strategies that take into account socio-demographic risk factors for low vaccination uptake are required.

Child, Preschool↗
PubMed2005

Toxic epidermal necrolysis in a premature infant of 27 weeks' gestational age.

Toxic epidermal necrolysis (TEN) is very rare in the newborn period. So far, three cases of TEN in newborns have been reported worldwide. We report a premature infant of 27 weeks' gestational age with TEN at 4 weeks of age. Sepsis treated by an antibiotic combination regimen preceding the TEN was a common feature of all four cases. In our patient, coagulase-negative staphylococci could be identified by blood culture, whereas the previously reported patients suffered from Klebsiella pneumoniae sepsis or Escherichia coli sepsis. Possibly, the uniform association with septic infection in the cases of TEN in the neonatal period might hint at a causal association, thus differentiating it from TEN in older children or adults.

Anti-Bacterial Agents↗
PubMed2005

Acute hemorrhagic pericarditis in a child with pneumonia due to Chlamydophila pneumoniae.

Chlamydophila pneumoniae is mainly responsible for respiratory tract infections but has also been associated with endocarditis and myocarditis. We report a case of pneumonia in a child with hemorrhagic pericardial effusion with a positive result by a new C. pneumoniae TaqMan PCR, suggesting a pericardial inflammation directly induced by C. pneumoniae. C. pneumoniae should be suspected in patients with community-acquired pneumonia and concurrent pericarditis. Empirical treatment with azithromycin seems feasible.

Acute Disease↗
PubMed2004

Blood culture sampling rates at a German pediatric university hospital and incidence of invasive pneumococcal disease.

BACKGROUND: Recent pediatric surveillance studies suggest the incidence of pneumococcal bacteremia, but not meningitis, is lower in Germany than in most developed countries. Suboptimal case assessment in routine clinical practice has been suspected of contributing to this apparent discrepancy. METHODS: We aimed to assess the blood culture sampling rate at a German pediatric university hospital and the disease burden associated with pneumococcal bacteremia in children under 5 years of age. The study design was retrospective, based on data-linkage and chart review. RESULTS: Blood cultures were frequently obtained in sepsis (96%; CI 78-99%) and meningitis (95%; CI 77-99%), but less commonly in pneumonia (49%; CI 43-54%) and fever without focus (48%; CI 38-59%). Pneumococci were the most common source of clinically significant bacteremia in previously healthy children. CONCLUSION: These blood culture sampling rates may be insufficient for the sensitive detection of pneumococcal bacteremia. Epidemiological surveillance based on poorly standardized diagnostic practices is prone to under-assessment.

Age Distribution↗
PubMed2003

A human flora-associated rat model of the breast-fed infant gut.

OBJECTIVES: Bacterial colonization of the infant gut may have important influences on the development of gastrointestinal, respiratory, and allergic disease. Early diet is a major determinant of the gut microflora. It is very difficult to carry out studies in human infants that can investigate the interaction of diet, flora, and mucosa. In this study we have developed an infant human flora-associated (IHFA) rat model to allow such investigation. METHODS: Germ-free infant rats were infected with fecal bacteria from exclusively breast-fed infants and were maintained on a modified infant formula for 8 weeks. The fecal and cecal contents were collected and compared with feces of breast-fed infants for bacterial populations, bacterial metabolites, and enzymes and for the ability to inhibit adhesion of pathogenic bacteria to human mucosal cells. RESULTS: The IHFA cecum and feces were dominated by lactic acid bacteria, Bifidobacterium, and lactobacilli, which were representative of the infant feces. The fecal short-chain fatty acid profile was dominated by acetic and lactic acid in a similar manner to human infant feces. Other bacterial metabolites were similar to those of the human infant. Rat intestinal samples were able to inhibit the adhesion of pathogens to mucosal cells, but to a lesser extent than the human samples. CONCLUSIONS: This IHFA infant model of the intestinal flora of the breast-fed infant is considered valid for studying the effect of diet on bacterial colonization and metabolism.

Animals↗
PubMed2002

Systemic activation of the immune system during ganciclovir treatment following intratumoral herpes simplex virus type 1 thymidine kinase gene transfer in an adolescent ependymoma patient.

During ganciclovir treatment of an adolescent ependymoma patient two weeks after intracranial implantation of HSVtk retroviral vector producer cells, increasing numbers of peripheral T- and B-cells were found as well as enhanced T-cell activation and elevated serum levels of interleukin 12 and soluble Fas ligand. These findings suggest the systemic activation of the immune system during ganciclovir treatment in our patient. The induction of an immune response by HSVtk/ganciclovir supports the concept of an anti-tumor vaccination effect by prodrug activating gene therapy systems and may open new promising perspectives for enhancing therapeutic efficiency by combined prodrug activating and immunological gene therapy strategies.

Adolescent↗
PubMed2001

Anti-infectious properties of the human milk fat globule membrane.

Secretory immunoglobulin A (sIgA), the predominant antibody fraction of human milk, represents a major protective factor against neonatal infection. Until now, sIgA had been identified only in the humoral fraction of human milk. For bovine milk an association between sIgA and the milk fat globule (MFG) membranes has been demonstrated. The aim of our study was to assess whether sIgA is associated with the MFG membranes in human milk. Using anti-sIgA-agglutinated human MFG and immune fluorescence microscopy, we demonstrated that sIgA is, in fact, associated with human MFG. Subsequently, by electrophoretic separation of human MFG membranes and Western blotting, we demonstrated specific sIgA bands, suggesting that sIgA is truly an integral part of the human MFG membrane. This may be of physiological relevance, as undigested and functional human MFG are found in the stools of the newborn.

Anti-Infective Agents↗
PubMed2001

Influence of glutamine and glycyl-glutamine on in vitro lymphocyte proliferation in children with solid tumors.

It is reported that the proliferative response of lymphocytes is lowered in patients with solid tumors. Glutamine is a major nutrient for rapidly proliferating cells. Unlike glutamine itself, the dipeptide glycyl-glutamine as a source for glutamine is stable in aqueous solutions ex vivo. In order to evaluate the possible therapeutic role of glutamine in lymphocyte proliferation, we investigated its influence on lymphocytes of children with solid tumors before and after chemotherapy. Lymphocytes were collected from 21 children and adolescents suffering from solid tumors (before and after chemotherapy) and from healthy controls. Glutamine and glycyl-glutamine, respectively, were added to cell cultures at concentrations between zero and 1.0 mmol/l. ConA or SAC served as T- or B-cell mitogens, respectively. The lymphocyte proliferation in the healthy control group was similar in degree to lymphocyte proliferation seen in the patients with solid tumors, regardless of the mitogen used. No difference in the degree of lymphocyte proliferation before or after chemotherapy was seen with either source of glutamine. Specific subgroups of malignancies showed trends that differed from the overall findings, but these differences were not found to be statistically significant. Routine supplementation with glutamine in children with solid tumors to enhance lymphocyte function is not supported by the data gained from in vitro proliferation tests.

Adolescent↗
PubMed2001

Potential role of human brain microvascular endothelial cells in the pathogenesis of brain abscess: inhibition of Staphylococcus aureus by activation of indoleamine 2,3-dioxygenase.

Cerebral abscess is a rare complication of staphylococcal septicemia in infants associated with high mortality and morbidity. In the pathogenesis of abscess formation, S. aureus, one major causative agent, interacts with endothelial cells of the brain vessels before reaching the central nervous system. This study examined the growth of S. aureus in human brain microvascular endothelial cells (HBMEC) cultures stimulated with cytokines. IFN-gamma inhibited S. aureus replication by the induction of indoleamine 2,3-dioxygenase (IDO) in HBMEC. This activation of IDO in HBMEC could be shown by RT-PCR and by detection of kynurenine in culture supernatants of activated cells. Resupplementation of L-tryptophan abrogated the inhibitory effect of IFN-gamma on the growth of staphylococci, hence confirming the activation of indoleamine 2,3-dioxygenase as being responsible for the induced bacteriostasis. Addition of TNF-alpha enhanced the IFN-gamma mediated antibacterial effects, whereas TNF-alpha alone had no influence on staphylococcal growth. Stimulation of HBMEC with IFN-gamma failed to activate inducible nitric oxide synthase (iNOS) and subsequent production of nitric oxide (NO). Thus, intra- and extracellular depletion of L-tryptophan seems to be an important process in the defense against staphylococcal brain abscesses by means of creating an unfavorable microenvironment.

Brain Abscess↗
PubMed2001

Restriction of Toxoplasma gondii growth in human brain microvascular endothelial cells by activation of indoleamine 2,3-dioxygenase.

One of the first steps in the development of cerebral toxoplasmosis is the penetration of the blood-brain barrier, which is comprised of microvascular endothelial cells. We examined the capacity of human brain microvascular endothelial cells (HBMEC) to interact with Toxoplasma gondii. We found that stimulation of HBMEC with gamma interferon (IFN-gamma) resulted in the induction of toxoplasmostasis. The capacity of HBMEC to restrict Toxoplasma growth after IFN-gamma stimulation was enhanced in the presence of tumor necrosis factor alpha (TNF-alpha). In addition, we found that IFN-gamma induced a strong induction of indoleamine 2,3-dioxygenase (IDO) activity in HBMEC, and this enzyme activity was enhanced by costimulation with TNF-alpha. The addition of excess amounts of tryptophan to the HBMEC cultures resulted in a complete abrogation of the IFN-gamma-TNF-alpha-mediated toxoplasmostasis. We therefore conclude that IDO induction contributed to the antiparasitic effector mechanism inducible in HBMEC by IFN-gamma and TNF-alpha.

Adult↗
PubMed2001

Superoxide anion generation in human milk macrophages: opsonin-dependent versus opsonin-independent stimulation compared with blood monocytes.

Macrophages are believed to play an important role within the immunoprotective effects of human breast milk. It was the purpose of this study to evaluate the capability of human milk macrophages (MMPhi) to generate superoxide anions (O2(-)) in comparison with peripheral blood monocytes (BMo) after stimulation with opsonized and unopsonized zymosan. Potential inhibitors of attachment and phagocytosis such as mannose and cytochalasin B were used. Expression of the mannose receptor on MMPhi was demonstrated by staining with MAb. BMo generated more O2(-) than MMPhi (417 +/- 79 versus 216 +/- 15 nmol O2(-)/mg protein, p < 0.05) after stimulation with opsonized zymosan. When unopsonized zymosan was used as a serum-independent stimulus, BMo generated slightly less O2(-) in comparison with MMPhi (150 +/- 34 versus 176 +/- 18 nmol O2(-)/mg protein, p < 0.05). These findings imply a higher proportion of opsonin-independent phagocytosis in MMPhi than in BMo (82 versus 36 %). Preincubation with mannose resulted in a significantly higher reduction of O2(-) generation in MMPhi compared with BMo stimulated with opsonized zymosan, whereas no difference was found when unopsonized zymosan was used. After addition of cytochalasin B, equal inhibition of O2(-) generation was observed regardless of the cell type or stimulus used. Thus, MMPhi are stimulated to a greater extent by serum-independent mechanisms than BMo. As opsonins like complement or IgG are rare in the colostrum and the neonatal intestinal environment, such a differentiation toward serum-independent phagocytic abilities could play an important role for protective functions of human MMPhi. Possible involvement of the mannose receptor and the beta-glucan receptor in this specialization are discussed.

Cells, Cultured↗
PubMed2000

Glycyl-glutamine improves in vitro lymphocyte proliferation in AIDS patients.

BACKGROUND: Glutamine (Gln) is a major nutrient for rapidly proliferating cells. Unlike glutamine itself, the dipeptide glycyl-glutamine as a source for Gln is stable in aqueous solutions ex vivo. In order to evaluate the possible therapeutic role of glycyl-glutamine on lymphocyte proliferation we investigated its influence on lymphocytes of AIDS patients and healthy controls under stimulation with different mitogens. MATERIAL AND METHODS: Lymphocytes were collected from 11 adult patients suffering from AIDS according to the CDC definition and from 7 adult healthy donors. Glutamine (Gln) and glycyl-glutamine (GlyGln), respectively, were added to cell cultures at concentrations between 0 and 1.0 mmol/l. ConA or SAC served as T or B cell mitogens, respectively. Plasma amino acid levels were determined. RESULTS: Proliferation upon ConA-stimulation with GlyGln-supplementation was similar to Gln-supplementation and peaked dose dependently at 1.0 mmol/l. When SAC was used Gln seemed slightly superior to GlyGln with a peak at 0. 4 mmol/l but the results did not reach the level of statistical significance. An identical response pattern was demonstrated in HIV-patients, however at lower absolute proliferation rates. Normal values could not be restored. Overall, the use of either source of glutamine in equimolar concentrations did not result in major differences of proliferation. Glutamine and glycin plasma levels did not differ between HIV patients and controls. CONCLUSION: GlyGln can be used as a substitute for Gln with regard to lymphocyte proliferation. Lymphocytes from AIDS patients show, as controls do, an enhanced proliferation under supplementation either glutamine source. Supplementation of GlyGln might enhance lymphocyte proliferation and thus improve immunity.

Acquired Immunodeficiency Syndrome↗
PubMed2000

Opsonophagocytosis versus lectinophagocytosis in human milk macrophages.

Some important immunoprotective effects of human breast milk have been attributed to the presence of macrophages. We investigated the generation of superoxide anion (O2-) by monocytes and human milk macrophages after stimulation with opsonized and unopsonized zymosan in the absence and presence of mannose as an inhibitor to investigate lectinophagocytic and opsonophagocytic properties. Peripheral blood monocytes generated more O2- than human milk macrophages (417,4 + 79,1 nmol O2-/mg protein vs. 216,1 +/-15,1 nmol O2-/mg protein, p<0,05) after stimulation with opsonized zymosan. When unopsonized zymosan was used as a serum-independent stimulus monocytes generated slightly less O2- in comparison to human milk macrophages (150,8 +/- 34,5 nmol/mg protein vs. 176,1 +/- 18 nmol O2-/mg protein, p<0,05). These findings demonstrate that the proportion of opsonin-independent phagocytosis in human milk macrophages is higher than in monocytes (82% vs. 36%). When mannose was used as an inhibitor a significantly higher reduction of O2- generation occurred in human milk macrophages compared to monocytes stimulated with opsonized zymosan, whereas no difference was found when unopsonized zymosan was used. These results indicate that human milk macrophages are stimulated to a greater extent by opsonin-independent mechanisms than blood borne monocytes. As the colostrum and the intestinal environment of the neonate offers only a little amount of opsonins like complement and immunoglobulin G, such a differentiation to lectinophagocytic properties could bear a great advantage for protective functions of human milk macrophages.

Adjuvants, Immunologic↗
PubMed2000

Relapsing polychondritis in childhood--case report and short review.

Relapsing polychondritis (RP) is a disease of unknown etiology and it is characterized by inflammation of the cartilage. While the clinical picture of RP in adults is well described, RP in childhood is poorly documented. We describe a young girl presenting with acute dyspnea, stridor and polyarthritis. The diagnosis of RP was made 2 years after first presentation, when auricular chondritis occurred. Based on a MEDLINE search, reports on RP in childhood were reviewed. The frequency of chondritis and systemic manifestations of RP in children was compared to data in adults and found to be very similar. RP in childhood can be a life-threatening and debilitating disease.

Adult↗
PubMed2000

Lymphocyte proliferation is possible with low concentrations of glycyl-glutamine.

The positive effect of glutamine on lymphocyte proliferation has previously been described. Its dipeptide glycyl-glutamine (GlyGln) is more stable than pure glutamine in aqueous solutions. The aim of our study was to investigate the relationship between lymphocyte proliferation and varying concentrations of glycyl-glutamine in vitro. Isolated human lymphocytes were stimulated with the mitogens phytohaemagglutinin (PHA), Concanavalin A (ConA), pokeweed mitogen (PWM), and Staphylococcus aureus (SAC). Glycyl-glutamine was added to yield final concentrations of 0-2 mmol/l. Overall, minimal concentrations of 0.01 mmol/l glycyl-glutamine were sufficient to enhance lymphocyte proliferation over baseline (glutamine-free) levels. No difference was found between concentrations in the "physiological" range of 0.4 mmol/l and very low concentrations (0.04-0.1 mmol/l) with SAC, ConA and PWM. Increasing the concentration beyond 0.4 mmol/l (up to 2.0 mmol/l) offered further gain with PHA-stimulation only. Lymphocyte proliferation under in vitro polyclonal stimulation is maintained even at very low concentrations of glycyl-glutamine. Raising the concentration above the equivalent of physiological levels does not seem to provide further benefit.

Adult↗