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Biomedical subjects

R Hartmann

Publications and source records attributed to R Hartmann.

At least 163 records · Page 9Linked to original sources

Can retinopathy be prevented?

Clinical retinopathy eventually develops in the majority of insulin dependent diabetics during several decades of metabolic abnormality. Early structural lesions short of clinical significance may occasionally be detected in children much more frequently, however, after puberty. Major factors modulating the development of retinopathy are duration of diabetes, glycemic control and blood pressure.

Adolescent↗

[Long-term study of anthracycline-induced cardiomyopathy in children and adolescents].

In order to detect changes in cardiac function, electrocardiographic, echocardiographic and radiologic studies were performed in 71 patients (age 1-26 yrs) who had been treated at the University Children's Hospital Berlin because of malignant diseases according to protocols of the DAL/GPO and had received anthracyclines (doxorubicin or daunorubicin) at cumulative doses up to 480 mg/m2 (median 280 mg/m2). Clinically overt cardiomyopathy was observed in one girl and required transient administration of digoxin. In 2 patients echocardiographic changes led to a reduction of the scheduled anthracycline doses. No patient died from congestive heart failure. During treatment, an increase in the cardiothoracic index was observed in 14 children, and in 16 the ECG showed pathological findings. A decrease in contractility to 25% or less as detected by ultrasound was seen in 15 patients. More than 50% of patients developed echocardiographical signs indicating an impairment of myocardial function. However, persistent changes were only found in 1 patient after discontinuation of treatment. Long-term echocardiographic follow-up studies for 4-48 months (median 14 months) after completion of anthracycline therapy were performed in 18 patients and the findings compared to matched-pair controls. The observed M-mode parameters were completely normal, and the ejection fractions calculated from the two-dimensional ultrasound investigations were in the normal range but slightly diminished compared to controls. Cardiac ultrasound is a non-invasive, reproducible and tolerable procedure for early detection of an anthracycline cardiomyopathy. In our patients, time of occurrence and the extent of pathological changes were not associated with the cumulative applied anthracycline doses.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

[Effect of 7S immunoglobulin substitution on the incidence and course of infection in cytostatic drug treated patients].

This retrospective analysis evaluates the effect of intravenously administered immunoglobulin against infections occurring during bone marrow depression after cancer chemotherapy in 85 children with leukemia and lymphoma. There was no statistical difference between patients with and without immunoglobulin administration neither when immunoglobulins were used prophylactically nor therapeutically in addition to antibodies during episodes of infection. Duration of fever, duration of antibiotic therapy, maximum of temperature, white blood cell counts, and kind of infections were comparable in 84 fever episodes in patients who had received immunoglobulin therapeutically and 69 fever episodes in patients who had not. This study supports the aspect that immunoglobulin administration does not have preventive or therapeutic efficacy on infections during cancer chemotherapy in children.

Adolescent↗

[Ototoxicity of cisplatin in children with malignant diseases].

Ten out of 20 children with malignant diseases who received cisplatin in combination with other drugs developed hearing impairment primarily at the higher and rarely also at the lower frequencies. The CDDP-ototoxicity was found to be dose-related and irreversible. Audiometric abnormalities were symmetrical and bilateral. Two patients had symptomatic hearing impairment. Ototoxicity was more severe with higher individual and higher cumulative doses. CNS-irradiation increases the ototoxic effect of CDDP. Audiometric testing at the beginning of chemotherapy and during chemotherapy is important to find out preexisting disturbances of hearing function and to recognize early developing hearing loss.

Adolescent↗

[Late sequelae of CNS recurrence of acute lymphoblastic leukemia in childhood].

Study objective was to evaluate retrospectively central nervous system (CNS) morbidity of children with acute lymphoblastic leukemia treated with intensive chemotherapy and cranial radiotherapy for a first isolated or combined CNS relapse. Neurological (Touwen), neuropsychological (CFT 20, Wechsler scales, d2 attention test) and neuromorphological (CT, MRI) assessments were performed in 17 children (9 girls, 8 boys) aged between 7 and 14 years. Patients were off therapy for median 4 years; cranial radiotherapy for CNS relapse (12-24 Gy) was given to all patients 2 to 9 years ago (median 5.5 years). Ten patients had received preventive cranial radiotherapy during front-line treatment, previously. In this group, the cumulative radiation dose ranged between 30 and 39 Gy. Patients received 12 to 30 intrathecal methotrexate doses (median 22). Compared with normative levels for age (100 points) performance IQ (89.9) and full scale IQ (92.0), Culture Fair IQ (88.3) and attention and concentration (90.9) were significantly impaired. Verbal IQ (95.5) was not significantly different from normal expectations. Neurological investigations of 16 patients showed mild signs in 7 (44%) of them, mostly of fine-motor skills and coordination, but no major motor disability. In MRI and CT, white matter changes or ventricular enlargement were noted in 10 of 16 patients (63%). Parent-completed questionnaires indicated problem behaviors in 5 children. Cumulative doses of methotrexate correlated significantly with neuropsychological test results. Children irradiated twice as well as girls had poorer cognitive functions, not being statistically significant. Despite pathological test results, all children attended a normal school and did not exhibit obvious impairment in daily life. In conclusion, CNS relapse and attendant therapy, mostly consisting of a second course of cranial radiotherapy, caused measurable intellectual deficits and CNS morbidity, which did not result in severely impaired performance. Periodic psychological und clinical examinations are recommended for recognition of delayed morbiditiy and early intervention.

Adolescent↗

Electric-acoustic stimulation of the auditory system. New technology for severe hearing loss.

Various devices have been developed to overcome the widespread phenomenon of different degrees of hearing deficits between mild and profound hearing loss. Basically, we differentiate between acoustic stimulation (hearing aids), restricted to cases with a partially functioning cochlear receptor, and electrical stimulation (cochlear implants), stimulating the auditory nerve directly in cases with profound or total hearing loss. For the first time, animal data have been collected that indicate the possibility of nearly interference-free use of both stimulation types simultaneously. In addition, we have gathered the first clinical patient experience, which confirms the encouraging results. Future implications for patients with severe high-frequency hearing loss are discussed.

Acoustic Stimulation↗

Plastic changes in the auditory cortex of congenitally deaf cats following cochlear implantation.

Congenitally deaf cats were used as a model for human inborn deafness and auditory deprivation. The deaf cats were supplied with a cochlear implant, chronically exposed to an acoustic environment and conditioned to acoustic stimuli. In case of early implantation the cats learned to make use of the newly gained auditory channel behaviourally. Neurophysiological and fMRI data showed that the central auditory system was recruited, if implantation took place within a sensitive period of <6 months.

Animals↗

Delayed maturation and sensitive periods in the auditory cortex.

Behavioral data indicate the existence of sensitive periods in the development of audition and language. Neurophysiological data demonstrate deficits in the cerebral cortex of auditory-deprived animals, mainly in reduced cochleotopy and deficits in corticocortical and corticothalamic loops. In addition to current spread in the cochlea, reduced cochleotopy leads to channel interactions after cochlear implantation. Deficits in corticocortical and corticothalamic loops interfere with normal processing of auditory activity in cortical areas. Thus, the deprived auditory cortex cannot mature normally in congenital deafness. This maturation can be achieved using auditory experience through cochlear implants. However, implantation is necessary within the sensitive period of the auditory system. The functional role of long-term potentiation and long-term depression, inhibition, cholinergic modulation and neurotrophins in auditory development and sensitive periods are discussed.

Age Factors↗

Structure elucidation of azotobactin 87, isolated from Azotobacter vinelandii ATCC 12837.

Chromopeptide siderophores (azotobactin 87-I and -II) were isolated from an iron deficient culture medium of Azotobacter vinelandii ATCC 12837 (= DSM 87). Their structures were elucidated by chemical degradation studies and spectroscopic methods, especially 2D-NMR-techniques. Total assignments of 1H-, 13C-, and 15N-resonances based on 2D-HOHAHA-, 1H/13C-HMQC-, 1H/13C-HMBC-, 1H/15N-HMQC/TOCSY-, and 1H/15N-HMBC-experiments are given as well as sequential information derived from 1H/1H-NOESY-, 1H/13C-HMBC- and 1H/15N-HMBC-experiments. Both Az 87-I and Az 87-II consist of a tetracyclic chromophore-- (1S)8,9-dihydroxy-4-oxo-2,3,4,5-tetrahydro-1H,10cH-3a,5,10b- triazaacephenantrylene-1-carboxylic acid--and a decapeptide chain linked with the N-terminus to the carboxy group of the chromophore containing also modified, non-proteinogenic amino acids. The sequence L-Ser-D-Ser-L-Hse-Gly-D-threo-OHAsp-Hse-Hse-Hse-D-N5OH-N5-R- Hbu-Orn-L-Hse was determined for Az 87-I, while Az 87-II contains a C-terminal L-Hse-lactone instead. Iron is chelated by the catecholic group of the chromophore, the beta-hydroxy aspartic acid, and the hydroxamate function formed by N5-hydroxyornithine and R-beta-hydroxybutyric acid.

Amino Acid Sequence↗