Biomedical subjects

M Bartsch

Publications and source records attributed to M Bartsch.

At least 19 recordsLinked to original sources

PubMed2000

Primary amides. A general nitrogen source for catalytic asymmetric aminohydroxylation of olefins.

N-Bromo,N-lithio salts of primary carboxamides have been shown to be efficient nitrogen sources for catalytic asymmetric aminohydroxylation of olefins, behaving much like the parent N-bromoacetamide in these reactions. alpha-Chloro-N-bromoacetamide is a particularly interesting nitrogen source, as it is functionalized for further reaction, including easy deprotection by treatment with thiourea.

Acetamides↗

PubMed2000

Serum androgen levels in adolescents with type 1 diabetes: relationship to pubertal stage and metabolic control.

Delayed sexual maturation is still frequently seen in adolescents with type 1 diabetes. A close relationship between insulin and androgen metabolism has been found in a number of studies. Our study was designed to investigate whether or not abnormalities in androgen secretion could play a role in the onset of sexual maturation in adolescents with type 1 diabetes. We have asked whether or not there was a correlation between daily insulin dosage, duration of diabetes, metabolic control, age, pubertal stage, and body mass index (BMI) versus serum androgen concentrations. Basal total and free testosterone, dehydroepiandrosterone-sulfate (DHEA-S), dihydrotestosterone (DHT), sex hormone binding globulin (SHBG) and 3alpha-androstanediol glucuronide (3alpha diol-G) plasma concentrations were measured in 36 pubertal boys and 31 pubertal girls with type 1 diabetes and in 59 sex- and pubertal stage-matched control subjects without diabetes. Significantly higher serum total testosterone (p<0.01) and free testosterone (p<0.05) levels were found in females and males with type 1 diabetes than in controls at pubertal stage 5. DHEA-S, SHBG, DHT and 3alpha diol G concentrations in patients with diabetes were not significantly different from those in controls. There was no correlation between daily insulin requirements and serum androgen levels. These data suggest that adolescents with diabetes have similar serum levels of DHEA-S, SHBG, DHT and 3alpha diol G as healthy subjects at all stages of puberty. However, there are significant differences in serum testosterone and free testosterone levels in adolescents with diabetes when compared to healthy, sex- and pubertal stage-matched controls in late puberty. We hypothesize that the increased testosterone levels in patients with diabetes could relate to reduced fertility in females, disorders of sexual maturation and an increased risk for cardiovascular complications later in life.

Adolescent↗

PubMed2000

[Hearing screening of high risk newborn infants].

OBJECTIVE: This prospective study reports on the prevalence of hearing impairment in an at-risk neonatal intensive care unit (NICU) population. DESIGN: From 1990 to 1998, 1062 neonates were screened with the use of transitory evoked otoacoustic emissions (TEOAE) and brainstem evoked response audiometry (BERA). RESULTS: 934 infants passed the primary screen for both ears, 75 for one ear, adding up to 95%. 17 infants (1.6%) were lost to follow-up. In fourteen infants (1.3%), bilateral hearing impairment above 30 dB was confirmed. While all children with hearing impairment belonged to the group of 862 children receiving aminoglycosides, only one of them presented no other risk factors. In twelve of the hearing impaired children other anamnestic factors, i.e. dysmorphism, prenatal rubella or cytomegaly, family history of hearing loss or severe peri- and postnatal complications seem to be more probable causes of the identified hearing loss. In one of these children, delayed onset or progression of hearing loss is suspected. CONCLUSIONS: From our data, aminoglycosides are not an important risk factor for hearing impairment, when serum levels are continuously monitored, as in our cohort. After adjustment for other risk factors, birth weight between 1000 gr and 1500 gr and a gestational age between 29 and 31 weeks were no predictive markers for hearing impairment. It might be speculated that the improved medical treatment in a NICU reduces the probability of hearing impairment for those two groups. Conductive hearing loss as a possible additional cause for hearing impairment was not studied in detail, but the high percentage of malformations detected (four out of fourteen hearing impaired infants) demands further monitoring, close follow-up, adequate treatment and counselling.

Audiometry, Pure-Tone↗

PubMed2000

Expression of apoptosis and cell cycle related genes in proliferating and colcemid arrested cells of divergent lineage.

Progression through the cell cycle and redirection of cells towards programmed cell death (apoptosis) are tightly inter-related processes. However the requirement for tissue and cell type specificity suggests that a wide variety of mechanisms are used to achieve the same purpose. To examine this issue, we investigated cell cycle (c-myc, p53, p21/WAF) and apoptosis related (bcl-2, bcl-X(L), bax-alpha) gene expression in two cell lines of very different origin under proliferating and apoptosis-inducing conditions. Transformed human osteosarcoma cells (MG63) and non-transformed human kidney embryonal fibroblasts (293-0) were kept in culture in medium containing 10% FCS and growth arrest was induced by the addition of 50 ng/ml colcemid. Colcemid treatment caused growth arrest and elevated expression of cyclin B1 protein in both cell lines. Apoptosis was significantly elevated in both cell lines after colcemid exposure for at least one cell cycle. However the pattern of expression of cell cycle and apoptosis related genes, determined by RT-PCR, was quite different between the two cell lines during exponential growth and cell cycle arrest. Colcemid treatment did not markedly influence c-myc, p53 and p21/WAF expression in MG63 cells but did suppress c-myc and increase p21/WAF in 293-0 cells. Furthermore colcemid treated MG63 cells exhibited elevated bcl-2 and bax-alpha expression while similar treatment of 293-0 cells resulted in decreased bcl-X(L) and slightly increased bax-alpha expression. While growth arrest and apoptosis were induced in both MG63 and 293 cells following colcemid treatment, the differences in gene expression suggest that the mechanism by which these cells determine cell fate is quite different and may determine the sensitivity of different cell populations to anti-neoplastic drug therapy. The distinct patterns of gene expression should be carefully defined before mechanisms of apoptotic cell death are studied.

Apoptosis↗

PubMed1998

Hearing screening in at-risk neonate cohort.

OBJECTIVE: This prospective study reports on the prevalence of hearing impairment in an at-risk neonatal intensive care unit (NICU) population. DESIGN: From 1990 to 1997, 942 neonates were screened with transient evoked otoacoustic emissions (TEOAE) and brainstem evoked response audiometry (BERA). RESULTS: 835 Infants passed the primary screen for both ears, 57 for one ear, adding up to 94.7%. Seventeen infants (1.9%) were lost to follow-up. In thirteen infants (1.4%), bilateral hearing impairment above 30 dB was confirmed. While all children with hearing impairment belonged to the group of 820 children receiving aminoglycosides, only one presented no other risk factors. In 11 of the hearing impaired children other anamnestic factors, i.e. dysmorphism, prenatal rubella or cytomegaly, family history of hearing loss or severe peri- and postnatal complications seem to be more probable causes of the identified hearing loss. CONCLUSIONS: From our data, aminoglycosides seem not to be an important risk factor for communication related hearing impairment, when serum levels are continuously monitored, as occurred in our cohort. After adjustment for other risk factors, birth weight between 1000 and 1500 g and a gestational age between 29 and 31 weeks were no predictive markers for hearing impairment. It might be speculated that the improved medical treatment in a Neonatal Intensive Care Unit (NICU) reduces the probability of hearing impairment for those two groups. Conductive hearing loss as a possible additional cause for hearing impairment was not studied in detail, but the high percentage of malformations detected (four out of 13 hearing impaired infants) demands further monitoring, close follow-up, counselling and adequate treatment.

Acoustic Stimulation↗

PubMed1998

High-Temperature In Situ Straining Experiments in the High-Voltage Electron Microscope.

: Design rules are described here for high-temperature straining stages for transmission electron microscopy. Temperatures above 1000 degreesC can be attained by electron bombardment of the specimen grips. Thermal equilibrium can be reached in a short time by carrying off the heat by water cooling. Some applications of this stage are described. Ferroelastic deformation was observed at 1150 degreesC in t' and partially stabilized zirconia, which changes the microstructure for successive dislocation plasticity. In the oxide-dispersion-strengthened alloy INCOLOY MA 956, dislocations are impeded by oxide particles and move smoothly between the particles. At high temperatures, both the resting and traveling times control the average dislocation velocity. In MoSi2 single crystals of a soft orientation, dislocations with 1/2<111> Burgers vectors are created in localized sources and move on {110} planes in a viscous manner. The dislocations in Al-Pd-Mn single quasicrystals are oriented in preferred crystallographic directions and move in a viscous way as well. On the basis of in situ observations, conclusions are drawn for interpreting macroscopic deformation behavior at high temperatures.

Journal Article↗

PubMed1996

Retinopathy of prematurity in infants of birth weight > 2000 g after haemorrhagic shock at birth.

BACKGROUND: The risk of retinopathy of prematurity (ROP) is associated with low birth weight and low gestational age. For ROP screening examination is recommended in infants weighing < or = 1500 g or of less than 32 weeks' gestational age. METHODS: From 1991 ROP screening was performed in 452 premature infants with either a birth weight < or = 1500 g (n = 303) or a birth weight > 1500 g (n = 149) and who required additional oxygen supplementation or underwent surgery with general anaesthesia before estimated term. RESULTS: Unexpectedly, three infants with birth weights between 2080 and 2325 g and a gestational age of 32 or 33 weeks developed stage 2 or 3 ROP. One of these underwent cryocoagulation. In three infants, preterm birth was induced by sudden placental abruption with severe prenatal blood loss followed by haemorrhagic shock. The umbilical cord packed cell volume was reduced to 0.14-0.19 (normal 0.43-0.63). All three infants underwent surgery with general anaesthesia within the first weeks of life. Of the remaining 449 infants none with a birth weight > 1650 g developed any stage of ROP. CONCLUSION: Severe prenatal blood loss requiring blood transfusions and surgery with general anaesthesia may induce higher stages of ROP even in infants with birth weights exceeding the usual screening criteria.

Abruptio Placentae↗

PubMed1992

[Measuring microcirculation after replantation and revascularization].

Eighty-four patients were evaluated following replantation or revascularization. Extremity function in daily and professional life was altogether satisfactory. Microcirculation investigations in eight patients included thermography, laser-doppler-flowmetry and photoplethysmography. The rewarming period and postocclusive hyperemia after standardized cooling of the upper extremity were determined. In areas of hypesthesia, the rewarming period was clearly delayed. In addition, reactive hyperemia after occlusion of circulation was significantly reduced.

Amputation, Traumatic↗

PubMed1992

[Digital luminescence radiography of premature and term infants. Possibilities and limitations].

Postmortem images of seven premature and term newborns, acquired with various conventional screen-film combinations and by a digital technique with appropriate radiation exposures, were compared. Images without and with simulated pathology were used in this study. With electronic manipulation of the computed radiographs we obtained well-balanced images with good contrast, and in many cases the artifacts were better visualized than with the conventional screen film. However, in our study no significant dose reduction for this young age group was possible with the digital technique compared with conventional screen film.

Humans↗

PubMed1992

[Plaster filling in surgical treatment of enchondroma--a justified therapeutic procedure?].

Enchondroma are the most frequent tumors of the hand. These benign tumours are characterized by slow growth, the lack of clinical symptoms and by accidental discovery. The surgical treatment of enchondroma includes resection of the tumor tissue from the bone matrix, and subsequent filling of the defect with autologous or homologous spongiosa or with sterile plaster of Paris. We showed in a period from 1982 to 1989 that there is no difference with respect to the clinical outcome between our patients receiving autologous spongiosa (n = 25) or plaster filling (n = 35). Owing to its simplicity and lack of additional surgery at the iliac crest, we prefer the method of plaster filling. Animal studies performed by our group have demonstrated that implanted plaster is transformed to spongiosa within four to ten weeks without adverse effects.

Animals↗

PubMed1990

[A pragmatic assessment of sense of smell].

A new clinical odour test was developed and validated in a clinical trial including 50 healthy volunteers as well as 35 patients suffering from smell disorders. The aromas were incorporated in an inert gas under disclosure from oxygen, avoiding impairment caused by oxidative transformation. Conventional smell test by Elsberg bottles was used as standard. The spray test proved to be equally effective in discriminating subjects suffering from smell disorders as the standard procedure. Moreover the spray test is feasible and long term constance of the substances is guaranteed.

Aerosols↗

PubMed1989

[Surgical treatment of distal humerus fractures in children].

From 1955 to 1987 414 children with supracondylar fractures of the humerus were treated at the surgical department of the University of Erlangen. Most important for the choice of treatment in supracondylar fractures was the classification of Baumann. 33 children concerning stage I were treated with cuff and collar or cast. Out of 381 patients with stage II and III Baumann's extension was used in 352 children; 29 had to be operated. The operation was indicated in a further 56 children. 20 of these had a lesion of the condylus radialis, 18 of the epicondylus ulnaris, 8 children showed diacondylar, 3 transcondylar lesions, 3 children had injuries of the condylus ulnaris and 4 more children showed splintered fractures. In 234 patients a follow-up was carried out according to the scheme of Morger. In 91% there was an ideal or good late result, in only 2% of the patients the result was unsatisfactory. The majority of distal fractures of the humerus can be treated conservatively with good results; operative treatment does not improve the functional and cosmetic results. It is indicated in complicated forms of fracture, in which satisfying results are not to be expected by conservative treatment.

Child↗

PubMed1987

[Primary and secondary chest wall tumors--diagnosis, therapy and results].

In a retrospective study 51 patients who underwent chest wall resection for malignant chest wall tumors were reviewed. There were 28 male and 23 female patients with ages ranging from 6 to 76 years (average 50). 34 patients had primary malignant neoplasms (including breast and lung) 17 had metastatic tumors. The tumor was located in the ribs in 45 patients and in the sternum in 6. Reconstruction was with prosthetic material in 16 patients and further plastic reconstruction in 10. Aggressive resection for malignant chest wall tumors and reliable reconstruction can be performed safely, and early wide resection proved to be a potentially curative treatment for primary neoplasms.

Adolescent↗

PubMed1985

Correlation of chloroplast and bacterial ribosomal proteins by cross-reactions of antibodies specific to purified Escherichia coli ribosomal proteins.

Immunological homology between chloroplast ribosomal proteins (r-proteins) from a higher plant (Spinacia) and bacterial r-proteins was examined using antibodies prepared against 35 purified Escherichia coli r-proteins. Cross-reactions were determined on cellulose acetate gels and on nitrocellulose paper, after electrophoretic transfer of r-proteins from one- and two dimensional polyacrylamide gels, using peroxidase and fluorescein-conjugated second antibodies for detection (immunoblotting). The specificity of positive cross-reactions was confirmed by absorption experiments using purified E. coli r-proteins. Antisera against five proteins of the small subunit and six proteins of the large subunit of E. coli ribosome (i.e. anti-S7, -S9, -S11, -S12, and -S19; anti-L1, -L2, -L3, -L6, -L13, and -L17) gave cross-reactions. As an inference from this work, and a recent study on the synthesis of certain chloroplast r-proteins in isolated chloroplasts (Eneas-Filho, J., Hartley, M. R., and Mache, R. (1981) Mol. Gen. Genet. 184, 484-488), we suggest that chloroplast r-proteins S7 and L2 are encoded in the organelle DNA.

Antibodies↗

PubMed1984

Evolution of obesity in young people in Busselton, Western Australia.

The height and weight measurement of 928 young people of Busselton were collected over a period of up to 11 years. The prevalence of obesity was low in early childhood and increased progressively through adolescence and adulthood, so that 9% of male subjects and 16% of female subjects aged 21 years or over, were obese. The prevalence and degree of obesity were both greater in female subjects than in male subjects. Although most obese young adults were not obese in childhood, 50% of those who were obese between the ages of 9 and 14 years were still obese when examined in young adult life, and were at greater risk of becoming obese adults than were their non-obese peers. Most subjects who subsequently became obese young adults were significantly heavier than their non-obese peers at all ages from the age of 6 years.

Adolescent↗

PubMed1984

Reconstitution of 50 S ribosomal subunits from Bacillus stearothermophilus with 5 S RNA from spinach chloroplasts and low-Mr RNA from mitochondria of Locusta migratoria and bovine liver.

Reconstitution experiments with 50 S ribosomal subunits from Bacillus stearothermophilus demonstrate that spinach chloroplast 5 S rRNA can be incorporated into the bacterial ribosome and yield biologically active particles, thereby establishing the eubacterial nature of chloroplast 5 S rRNA. In contrast, mitochondria from Locusta migratoria or bovine liver do not appear to contain discrete, low-Mr RNAs, which can replace 5 S rRNA in the functional reconstitution of B. stearothermophilus ribosomes.

Animals↗

PubMed1983

Chemical accessibility of the 4.5S RNA in spinach chloroplast ribosomes.

We have examined the accessibility to diethylpyrocarbonate of spinach chloroplast 4.5S ribosomal RNA when free and when it is part of the ribosomal structure. The modifications in free 4.5S RNA were found mostly in single-stranded regions of the secondary structure model proposed in our previous paper (Kumagai, I. et al. (1982) J.B.C. 257, 12924-28): adenines at positions 17, 19, 33, 36, 54, 55, 60, 64, 68, 72, 77, 86 and 87 were identified as the reactive residues. On the other hand, in 4.5S RNA in 70S ribosomes or 50S subunits, adenine 33 was exclusively modified, and its reactivity was much higher than in free 4.5S RNA. This highly accessible A33 of spinach 4.5S RNA is located within a characteristic seven nucleotide sequence, which is found in the 4.5S rRNAs from spinach, tobacco and a fern but deleted in 4.5S RNAs from maize and wheat.

Base Sequence↗

PubMed1983

Comparative structural analysis of cytoplasmic and chloroplastic 5S rRNA from spinach.

5S rRNAs from Spinacea oleracea cytoplasmic and chloroplastic ribosomes have been subjected to digestion with the single strand specific nuclease S1 and to chemical modification of cytidines by sodium bisulphite in order to probe the RNA structure. According to these data, cytoplasmic 5S rRNA can be folded as proposed in the general eukaryotic 5S rRNA structure (1) and 5S rRNA from chloroplastides is shown to be more related to the general eubacterial structure (2).

Base Sequence↗