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Biomedical subjects

I Richter

Publications and source records attributed to I Richter.

At least 19 recordsLinked to original sources
PubMed2004

[Communal health promotion in child and adolescent health services -- report on the experience with a organisational model for setting up an interdisciplinary network in a socially important area].

This report focusses on health promotion for children adolescents und families and on the aspects of organisation and resources. In 1991 the Public Youth Health Care (KJGD), a community health service for children und adolescents, set up a multi-professional "district committee" of distributors in leading positions in a socially important area (social workers, school teachers, kindergarten teachers, councillors, medical personnel, architects and town planners etc.). Medical examinations of all school beginners and children with special educational needs formed the basis of the social paediatric observations and data. Until 2003 the author was responsible for the management and coordination of this local interdisciplinary district committee of leading representatives from local social and educational organisations as well as town councillors who created a local multi-professional network. The district health reports of the discussions in the district committee including the different professional aspects of health promotion were passed on to the local politician actively involved in the discussions with specialists and invested in social and health promotion projects. Social paediatric issues and preventative strategies became part of the work in social and educational organisations in the area und the city. A healthy environment for children und families was promoted. For the KJGD the conceptual work with distributors in leading positions led to initiatives for communal health promotion making time-saving use of existing resources.

Adolescent↗
PubMed1999

Variable phenotype associated with Ser505Asn-activating thyrotropin-receptor germline mutation.

Constitutively activating thyrotropin-receptor (TSHR) germline mutations have been identified as a molecular cause of hereditary nonautoimmune hyperthyroidism. To date, seven cases of familial and six cases of sporadic nonautoimmune hyperthyroidism have been described associated with 13 different TSHR germline mutations, with a variable clinical course. We report the case of a 12.3-year-old girl with a history of thyrotoxicosis since the age of 11 months who developed diffuse thyroid hyperplasia at the age of 4.5 years. The patient has required continuous moderate-dose antithyroid medication, to maintain euthyroidism. There were no clinical signs of autoimmune thyroid disease and autoantibodies were negative. An activating germline mutation in the TSHR gene was suspected and was found in TSHR exon 10 (Ser505Asn) but was absent in the girl's mother. This same mutation, was first reported in a patient with severe intrauterine hyperthyroidism with early and progressive goiter development. Our patient had a significantly less severe clinical course with later onset compared to the original patient with the same TSHR germline mutation.

Child↗
PubMed1997

Evaluation of oro-coecal transit time: a comparison of the lactose-[13C, 15N]ureide 13CO2- and the lactulose H2-breath test in humans.

OBJECTIVE: The lactulose H2-breath test is the most widely used non-invasive approach for evaluation of orocoecal transit time (OCTT). In the present study, doubly-labelled lactose-[13C, 15N]ureide (DLLU) was synthesized to investigate the OCTT in comparison to the conventional lactulose H2-breath test. Additionally the bacterial breakdown rate (BBR) and rate of elimination and the metabolic pathways of the cleavage products of DLLU (13CO2, [15N]urea, and 15NH3) were investigated. DESIGN AND SUBJECTS: In a first study, DLLU was administered as a single oral-pulse-labelling (dosage: one gram) either without and after pretreatment of five grams of unlabelled lactoseureide (LU) on the day prior to the study to twelve healthy adult volunteers after breakfast. Breath and urine were collected in one and two hour-intervals, respectively, over a one-day period. 13C-enrichment in breath as well as 15N-enrichment in urine fractions were measured by continuous flow-isotope ratio mass spectrometry (CF-IRMS). In a second study, lactulose was administered to the same subjects (dosage: ten grams). Breath was collected in quarter, half and one hour-intervals over a ten hour-period. Hydrogen concentration in breath was analysed using an electrochemical detector. RESULTS: The comparison of the lactose-[13C]ureide 13CO2-breath test and the lactulose H2-breath test showed that the mean increase of the 13C-enrichment in CO2 occurred 1.18 h later than the mean increase of H2 in breath. The resulting OCTTs derived from the two methods were 3.02 +/- 1.4 and 1.84 +/- 0.5 h (P < 0.05) and the corresponding BRs were 9.63 +/- 3.4 and 6.07 +/- 1.7 h (P < 0.01), respectively. The 15N-enrichment of urinary urea and ammonia without and after pretreatment with LU started between two and three hours after DLLU-administration. The cumulative percentage urinary excretion of the 15N- and 13C-tracer was 29.9% and 13.6% respectively, and was slightly increased after LU-pretreatment to 32.1% and 14.6% of the dose administered. A total of 35.2% of the 13C was found to be exhaled and remained approximately constant after LU-pretreatment (36.2%). CONCLUSIONS: The use of the lactulose H2-breath test for evaluation of the OCTT showed a statistically significant shortening of 1.18 h in comparison to the lactose-[13C]ureide 13CO2-breath test in healthy adults. The most important limitations of the lactulose H2-breath test are its low specificity and sensitivity due to dose-dependent accelerations of OCTT, interfering H2-rise from malabsorbed dietary fibre and H2-non-producers. In contrast, our lactose-[13C]ureide 13CO2-breath test was confirmed to avoid these disadvantages and to yield reliable results. This test is recommended especially if higher sensitivity and specificity is required, if IRMS-technique is available and if lactulose H2-tests lead to insufficient results.

Breath Tests↗
PubMed1997

Heterogeneity and clonality among isolates of Mycobacterium kansasii: implications for epidemiological and pathogenicity studies.

The reservoir and transmission route of Mycobacterium kansasii are largely unknown. In addition, culturing of M. kansasii from human sources is not proof of disease because it may represent colonization rather than infection. Unfortunately, investigation of the epidemiology and pathogenicity of M. kansasii is complicated by evidence of heterogeneity within the species. A comprehensive study by detailed genotypic analysis of a large collection of M. kansasii isolates (n = 276) from various geographical sources within Europe was conducted. Five defined subtypes of M. kansasii were identified; of these subtypes, type I represents the most common isolate from humans. Although phylogenetic analysis confirmed its relationship to the other M. kansasii types, significant sequence divergence was found at the 16S-23S intergenic spacer. Analysis of the chromosomal polymorphism of type I demonstrated a marked clonal structure for this particular organism. Because M. kansasii is becoming a significant pathogen among immunodeficient hosts, future epidemiological and pathogenicity studies should take into consideration both the heterogeneity within the species and the apparent clonality of the most prevalent M. kansasii isolates infecting humans.

Bacterial Proteins↗
PubMed1995

Mycobacterium conspicuum sp. nov., a new species isolated from patients with disseminated infections.

A new type of slowly growing, nonphotochromogenic mycobacterium was recovered from two patients with disseminated disease. The growth characteristics, acid fastness, acids were consistent with those for Mycobacterium species. The results of biochemical investigations, lipid analyses, and comparative 16S rRNA sequencing showed that these isolates represent a new slowly growing Mycobacterium species which is named Mycobacterium conspicuum.

Adult↗
PubMed1992

Stimulation of nitrogen and whole-body protein metabolism in growth hormone-deficient children by recombinant human growth hormone: relationship to growth.

The effect of a mammalian-cell-derived recombinant human growth hormone (rhGH) on nitrogen and whole-body protein metabolism was assessed in 12 children with complete growth hormone (GH) deficiency. All the patients received single oral doses of 15N-glycine (95 atom % 15N), 20 mg/kg body weight, prior to and following 7 days of treatment with rhGH, 1.7 IU/m2 body surface area (BSA) per day, administered subcutaneously. Prior to rhGH, mean urinary 15N-nitrogen excretion was 42.8 +/- 8% of the administered dose, which fell significantly to 22.8 +/- 7% during rhGH administration (p < 0.0001). Stimulation of protein metabolism by rhGH resulted in a protein net gain rate of 1.1 +/- 0.4 g/kg/day, which was significantly higher than the 0.6 +/- 0.5 g/kg/day rate seen prior to rhGH (p < 0.001). In patients subsequently placed on daily subcutaneous injections of rhGH 1.7 IU/m2 BSA, mean height velocity standard deviation score (HV SDS) for chronological age significantly increased from -3.8 +/- 2.6 to +8.5 +/- 3.1 and +3.3 +/- 2.2, during the 1st and 2nd years of treatment, respectively. However, there was no correlation between the long-term response to rhGH treatment and the short-term changes in nitrogen or protein metabolism in GH-deficient children.

Adolescent↗
PubMed1991

Replacement of lysine 269 by arginine in Escherichia coli tryptophan indole-lyase affects the formation and breakdown of quinonoid complexes.

Lysine 269 in Escherichia coli tryptophan indole-lyase (tryptophanase) has been changed to arginine by site-directed mutagenesis. The resultant K269R mutant enzyme exhibits kcat values about 10% those of the wild-type enzyme with S-(o-nitrophenyl)-L-cysteine, L-tryptophan, and S-benzyl-L-cysteine, while kcat/Km values are reduced to 2% or less. The pH profile of kcat/Km for S-benzyl-L-cysteine for the mutant enzyme exhibits two pK alpha values which are too close to separate, with an average value of 7.6, while the wild-type enzyme exhibits pK alpha values of 6.0 and 7.8. The pK alpha for the interconversion of the 335 and 412 nm forms of the K269R enzyme is 8.3, while the wild-type enzyme exhibits a pK alpha of 7.4. Steady-state kinetic isotope effects on the reaction of [alpha-2H]S-benzyl-L-cysteine with the K269R mutant enzyme (Dkcat = 2.0; D(kcat/Km) = 3.9) are larger than those of the wild-type enzyme (Dkcat = 1.4; D(kcat/Km) = 2.9). Rapid scanning stopped-flow kinetic studies demonstrate that the K269R mutant enzyme does not accumulate quinonoid intermediates with L-alanine, L-tryptophan, or S-methyl-L-cysteine, but does form quinonoid absorption peaks in complexes with S-benzyl-L-cysteine and oxidolyl-L-alanine, whereas wild-type enzyme forms prominent quinonoid bands with all these amino acids. Single wavelength stopped-flow kinetic studies demonstrate that the alpha-deprotonation of S-benzyl-L-cysteine is 6-fold slower in the K269R mutant enzyme, while the intrinsic deuterium kinetic isotope effect is less for the K269R enzyme (Dk = 4.2) than for the wild-type (Dk = 7.9). The decay of the K269R quinonoid intermediate in the presence of benzimidazole is 7.1-fold slower than that of the wild-type enzyme. These results demonstrate that Lys-269 plays a significant role in the conformational changes or electrostatic effects obligatory to the formation and decomposition of the quinonoid intermediate, although it is not an essential basic residue.

Arginine↗
PubMed1989

[Herpes simplex virus infection in the first weeks of life].

Most neonatal Herpes-simplex-virus infections are the result of virus acquisition during passage through the birth canal. Transplacental transmission of HSV is seldom. The infection is mostly localized at the skin, eyes and central nervous system. The disseminated HSV-infection represents as the most severe clinical picture. It is reported about meningoencephalitis caused by HSV in 3 infants in the first weeks of life. The therapeutic success of antiviral chemotherapeutics depends very much on their application at an early stage of the disease, which can be recognized by cerebral sonography and detection of IgM-antibodies against HSV.

Acyclovir↗
PubMed1989

[Results of ultrasound brain studies in clinically normal newborn infants].

Ultrasound investigations demonstrating intracranial hemorrhages (periventricular intraventricular hemorrhage-PVH/IHV) were performed in 401 term newborns. Without consideration the mode of delivery incidence of intracranial hemorrhage was 4.7%. There were only subependymal hemorrhages grade 1 and 2. In case of vaginal-operative delivered children frequency of hemorrhage in forceps delivered babies was really lower than in vacuum extracted newborns.

Birth Weight↗
PubMed1989

[Ullrich-Turner syndrome and anorexia nervosa--an association?].

It is reported about the clinical progress of a 15 years old girl suffering from anorexia nervosa with Ulrich-Turner's syndrome. Etiological aspects are discussed. It is derived from calculations that there is a suspicious fact of an association of both disorders.

Adolescent↗
PubMed1988

Astrocytes synthesize and secrete alpha 2-macroglobulin: differences between the regulation of alpha 2-macroglobulin synthesis in rat liver and brain.

alpha 2-Macroglobulin (alpha 2M) is an important proteinase inhibitor both in the blood and in the interstitial space of many mammalian species. Recently, occurrence of alpha 2M in human and fetal rat brain has been reported. However, its cellular origin remained obscure. Here it will be shown that astroglial cells cultured from newborn rats synthesize and secrete alpha 2M. In addition to astrocyte primary cultures a rat astrocytoma cell line, C6-cells, also synthesize and secrete alpha 2M. In contrast to hepatocytes of the adult rat, where alpha 2M is expressed as an acute-phase protein and where glucocorticoids and monocyte-derived factors are required for its synthesis, alpha 2M synthesis in astrocytes of newborn rats is independent from both. It is therefore concluded that expression of alpha 2M is differently regulated in the liver of the adult rat and fetal or neonatal brain.

Animals↗
PubMed1988

[Sonography as an aid in the early diagnosis of herpes simplex encephalitis].

In 3 infants with meningoencephalitis caused by Herpes simplex viruses the findings of cerebral sonography corresponded with those of computerized tomography and electroencephalography. The therapeutic success of antiviral chemotherapeutics depends very much on their application at an early stage of the disease, which can be recognized by cerebral sonography.

Antibodies, Viral↗
PubMed1987

Evidence for colonic absorption of protein nitrogen in infants.

The absorption of protein nitrogen by the colon was assessed in 6 infants with colostomy by giving 15N yeast protein in a dosage of 5-20 mg 15N/kg (92.4 atom-% 15N). The absorption of 15N ranged between 87.1 and 98.1% of the administered dose, and the retention in the protein pool ranged between 79.0 and 94.2%. The incorporation of 15N in the plasma proteins was demonstrated by 15N excess values between 0.02 and 0.10 atom-%. The results suggest that the colon can assimilate proteins when insufficient absorption of protein nitrogen in the small intestine occurs. The breakdown of protein is thought to result from the action of colonic flora.

Colon↗
PubMed1987

15N tracer techniques for the differential diagnosis of dwarfism and prediction of growth hormone action in children.

[15N]Glycine in a single oral dose was used to study nitrogen turnover in 18 short children, aged 3-14 yr. On the basis of their serum GH responses to insulin-induced hypoglycemia, the patients were divided into 3 groups: complete GH deficiency (GHD; n = 5); partial GH deficiency (pGHD; n = 6), and children with constitutional growth delay and familial short stature (CGD/FSS; n = 7). The mean 48-h renal excretion of 15N by patients with GHD was 66.09 +/- 14.12% (+/- SD) of the tracer dose. This decreased to 27.64 +/- 5.33% after two injections of 10 IU/m2 GH (P less than 0.001). 15N excretion by patients with pGHD was 47.19 +/- 13.42%, and it decreased after GH injection to 22.69 +/- 4.58% (P less than 0.005). Patients with CGD/FSS had 15N excretion of 37.27 +/- 5.68%, and it did not change in response to GH. The mean protein synthesis rate in GHD patients was extremely low, and it increased after GH injection from 0.99 +/- 0.46 to 3.53 +/- 0.43 g/kg X day. In pGHD patients the protein synthesis rate increased from 2.62 +/- 0.84 to 4.50 +/- 1.09 g/kg X day. The CGD/FSS patients had no change in protein synthesis rate after GH. Our results suggest that studies of the metabolism of [15N]glycine might be of value in predicting responsiveness to GH therapy.

Adolescent↗