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Biomedical subjects

H M Weinmann

Publications and source records attributed to H M Weinmann.

At least 19 recordsLinked to original sources
PubMed1994

MRI assessment of myelination: an age standardization.

777 cerebral MRI examinations of children aged 3 days to 14 years were staged for myelination to establish an age standardization. Staging was performed using a system proposed in a previous paper, separately ranking 10 different regions of the brain. Interpretation of the results led to the identification of four clinical diagnoses that are frequently associated with delays in myelination: West syndrome, cerebral palsy, developmental retardation, and congenital anomalies. In addition, it was found that assessment of myelination in children with head injuries was not practical as alterations in MRI signal can simulate earlier stages of myelination. Age limits were therefore calculated from the case material after excluding all children with these conditions. When simplifications of the definition of the stages are applied, these age limits for the various stages of myelination of each of the 10 regions of the brain make the staging system applicable for routine assessment of myelination.

Adolescent↗
PubMed1994

Delayed myelination in children with West syndrome: an MRI-study.

Eighteen children with West syndrome underwent MRI-examination of the brain. Five children were examined twice. Myelination of ten regions of the brain was retrospectively assessed on the MRI-examinations. The children could be divided in three groups of main diagnosis (cryptogenic West syndrome, tuberous sclerosis, pre-/perinatally acquired brain lesions). Delays in myelination were found in 17 out of a total of 23 examinations. In children with cryptogenic West syndrome and with tuberous sclerosis myelination was normal or only mildly delayed in the first month after onset of the spasms, but delays seemed to increase in the course of the West syndrome in these groups. In children with pre- or perinatally acquired brain lesions severe delays of myelination could be found already in the first weeks after the onset of the West syndrome. The assessment of myelination can therefore contribute to the diagnosis and understanding of the underlying disease in children with West syndrome.

Age of Onset↗
PubMed1992

Comparative coherence studies in healthy volunteers and Down's syndrome patients from childhood to adult age.

Within the scope of the Munich Pediatric Longitudinal Study, EEG coherence was studied in 212 Down's syndrome patients and 342 healthy controls aged from 6 months up to 30 years. The digitalized EEG records were subjected to spectral analysis. Frequency band-related coherences were calculated to reveal age-specific differences in the functional relationship between two brain areas in Down's syndrome patients and controls. The results show that in the "eyes-open" state the intra-hemispheric coherence in the alpha band was significantly lower (P less than 0.05) in the Down's syndrome patients than in the controls whereas that in the delta bands it was generally higher. The intra-hemispheric coherence in the "eyes-closed" state was generally higher in the Down's syndrome groups than in the controls; however, significant differences could be detected only in some age groups. The age-specific development of coherence in the inter-hemispheric parieto-occipital region was almost identical in Down's syndrome children as in controls, both with open and closed eyes. The most distinct differences were found in the fronto-central inter-hemispheric coherence (P less than 0.01), while the coherence deficiencies in the Down's syndrome group became more prominent with increasing age from school age onwards. These electrophysiological results are compared with the results of neuropathological and neurophysiological studies of other authors. It can be suggested that there are correlations with a significantly small number of dendritic spines in Down's syndrome patients, which was determined in neuropathological examinations. A neuronal model of interpretation is presented which explains the increasing developmental deficit with age in Down's syndrome children.

Adolescent↗
PubMed1989

[CO2-stunning of swine for slaughter from the anesthesiological viewpoint].

For investigations of CO2-stunning of feeder- and slaughter-pigs parameters of behaviour, blood-gas-analyses and electroencephalograms were chosen. The following results were obtained: 1. Blood-gas-analyses proved that the CO2-stunning does not produce unconsciousness due to a lack of oxygen. 2. The criterias of general anaesthesia: unconsciousness, muscle-relaxation and analgesia with total reversibility could be confirmed. 3. The violent convulsive symptoms were evaluated as reactions identical with the stage II of GUEDEL's scheme of anaesthesia. 4. Muscular agitation, which sometimes appeared a few seconds before the stage of excitation, was judged to belong either to the start of the excitation phase or to the end of Guedel's stage of analgesia, during which the sensitivity is decreased. Neither study of behavior nor objective measurements showed, during the first 10 to 20 seconds of exposure to the CO2, any sign of pain or suffering related to the Act for Prevention of Cruelty to Animals, and accordingly such suffering should not be ascribed to the CO2 stunning method.

Abattoirs↗
PubMed1988

[Herpes encephalitis in infancy].

Since antiviral chemotherapy is available herpes encephalitis has become of great importance among viral affections of the central nervous system. Five young infants are presented with special problems of this disease and its diagnostic possibilities especially serological and imaging methods (CT scan, nuclear magnetic resonance tomography, ultrasonography of the brain) as well as electroencephalography. Clinical symptoms are very important since all those methods are not sufficient for early diagnosis and prompt onset of antiviral chemotherapy. Herpes encephalitis should be considered after apparent febrile seizures with focal symptoms as well as increasing disturbance of consciousness as manifestation of acute encephalopathy.

Acyclovir↗
PubMed1985

Fibromatosis hyalinica multiplex (juvenile hyalin fibromatosis). Light microscopic, electron microscopic, immunohistochemical, and biochemical findings.

Fibromatosis hyalinica multiplex juvenilis (juvenile hyalin fibromatosis) is a very rare mesenchymal dysplasia, probably inherited as an autosomal-recessive trait. Two nonrelated cases are reported. Among the clinical features, the most impressive lesions are multiple slowly growing subcutaneous nodules, hypertrophic gingiva, flexural contractures with joint stiffness and radiolucent bone destructions. Light microscopic examination of the nodules reveals tumor-like deposits of an amorphous hyaline ground substance with delicate staining properties situated partly between cellular and vascular areas. Ultrastructural characteristics are cystic, dilated rough endoplasmatic reticulum and cystic Golgi vesicles which contain a fine fibrillar material that is also found in the ground substance. Immunohistochemical examination shows collagen type I and type III in the hyaline material, but not type II and type IV. Quantitative biochemical investigation reveals a normal ratio of collagen types I and III.

Adolescent↗
PubMed1985

Z-transformed EEG power spectra of children with Down syndrome vs a control group.

Standardized EEG records of eighty-eight children with Down syndrome aged between six months and five years were analysed. The EEGs were digitalized, evaluated by spectral analysis, and subjected to z-transformation, a method which allows a direct comparison of the Down syndrome children with a normal control group (Munich Developmental Longitudinal Study). The results show a significant increase in absolute power, especially theta power; the absolute alpha power is less markedly increased or even decreased. The most significant differences, however, are observed when calculating the relative alpha power. Children with Down syndrome show a reduced relative alpha power already at the age of six months, and this reduction becomes even more prominent with growing age.

Child↗
PubMed1984

Prevalence of partial deficiency of red cell triosephosphate isomerase in Germany--a study of 3000 people.

During a heterozygote screening of nearly 3000 persons, triosephosphate isomerase (TPI) deficiencies in erythrocytes were discovered in 11 unrelated persons, showing a residual activity between 39 and 76% of normal activity. Extensive genealogic studies were performed to confirm that these persons with TPI deficiency were heterozygous carriers. The total heterozygote frequency of triosephosphate isomerase deficiencies was 3.7/1000. The persons with heterozygous deficiency could be divided into two categories. Subjects of category I had a mean residual activity of 49% of the expected normal activity and were represented by a frequency of 1.3/1000. Subjects of category II had a mean residual activity of 67% of the expected normal activity and were represented by a frequency of 2.4/1000. None of the heterozygous persons showed an electrophoretic variant. The immunologic specific activity was normal with one exception. Therefore, we assume that in many cases of our heterozygous TPI-deficiencies a TPI protein with a normal specific activity is synthesized to a diminished degree.

Carbohydrate Epimerases↗
PubMed1983

[Development of the electroencephalogram in children--comparison of visual and automatic evaluation].

EEGs were recorded of 399 normal children, age 6 months to 5 years, in the Munich Pediatric Longitudinal Study. In all age groups bipolar EEG derivations were recorded with eyes open; in 259 children (age 3, 4 and 5 years) also with closed eyes. The visual evaluation--using a computer adapted evaluation sheet--showed a dominant activity of 5.5 Hz in 6 months old children, of 9 Hz in 5 years old children (eyes open). The mean amplitudes of the dominant activity decreased by 10 microV during this time. With eyes closed the dominant activity in the parieto-occipital area showed an increase from 7.7 to 8.5 Hz. The amplitude of 40-50 microV in the parieto-occipital areas was higher than in the frontal and temporal areas (25-30 microV). Examination with spectral analysis showed a reduction of the relative power in the delta range from 77 to 69% with a simultaneous increase in the alpha range from 3 to 10%. The peak frequencies showed an age dependent development corresponding to the visual analysis. Under the condition eyes open, the mean values of peak frequencies showed an increase from 8.6 to 9.5 Hz in the fronto-central areas and from 8.5 to 9.4 Hz in the occipital areas. With eyes closed the increase of peak frequencies reached up to 0.6 Hz for the age of 4 to 5 years. Age classification is more exact with spectral parameters. Compared to visual parameters, up to 29% more children were classified in the correct age-groups by spectral parameters. As expected the recognition rates decreased in older children.

Cerebral Cortex↗
PubMed1980

[Automatic recognition of age - specific development of the EEG in infancy and early childhood - a five year follow-up study (author's transl)].

This study was initiated with a view to early detection of dysfunctions of the central nervous system (CNS) and to observe the physiological development of the CNS by means of EEG obtained in the age-groups: new-born, half, 1, 2, 3, 4 and 5 years. This was supported by standardized clinical examinations for neurological and somatic findings and by standardized tests of psychomotoric and intellectual development. In this investigation the data as used for automatic processing consisted of 110 EEGs in the age-groups: half, 1, 2, 3 and 4 years. Bipolar EEGs were recorded using "ten-twenty" method with the following leads: F4--C4, P4--O2, F3--C3 and P3--O1. For feature extraction three methods of data reduction were applied, i.e. interval-amplitude, spectral analysis and the autoregressive model. From the features thus obtained, age-specific frequency parameters were selected by statistical methods; further evaluation was performed by cluster and discriminant analysis. The former showed an unequivocal case grouping for each age-group. Using unmatched samples of only clinically healthy children from the three age-groups 1/2, 1 and 2 years, linear discriminant analysis were applied to the parameters of the three methods of data reduction. This procedure yields in mean recognition rates of 95%, 98% resp. 98% in hold-one-out classification. Similar results are obtained with samples from four or five age groups (1/2 to 4 years). The results of this type of automatic EEG analysis show that discriminant analysis can be used to allocate EEGs to specific age-groups; hence, it may readily be ascertained whether differences between chronological age and development age as evidenced by the EEG exist.

Age Factors↗
PubMed1980

[The biphasic response in ERA (author's transl)].

Investigations (1975) of dyslectic children showed a biphasic evoked response summation curve. Four groups with distinct latencies of the biphasic curves were found. All children were expertly trained during the following years. Check-ups showed a consistent improvement in dichotic test results. Children having a biphasic curve in the first showed this again in the second investigation. Dyslectic qualities can be overcome by expert teaching and logopaedic exercises. Similar investigations were carried out with children showing various kinds of speech handicaps and with old age patients (without pathological ear problems). It is still questionable if the biphasic appearance shows "competition" of right and left hemisphere or whether it is a true organic failure of the brain to transmit acustic information from each ear to the central hearing regions (i.e., dichotic tests).

Aged↗