Buchbesprechungen

Ohne Zusammenfassung     

Comparison of three methods to measure absolute cerebral hemoglobin concentration in neonates by near-infrared spectrophotometry

Three methods by which to determine absolute total cerebral hemoglobin concentration (tHb in micromol/L) by near-infrared spectrophotometry (NIRS) have evolved: (1) tHbo, requiring oxygenation changes and arterial oxygen saturation measurements as a reference using a relative NIRS algorithm, (2) tHbg, using a geometrical multidistance principle and (3) tHbgo, a combination of both. The aim of this study was to compare the three methods quantitatively. Sixteen clinically stable preterm infants with a mean gestational age of 29.6 (range of 25.1-36.4) weeks, birthweight of 1386 (680-2820) g and a postnatal age of 2.5 (0.5-6) days, who needed supplemental oxygen, were enrolled. The mean+/-standard deviation tHbg was 150.2+/-41.8 micromol/L (range of 61.6-228.9 micromol/L), the tHbo was 62.1+/-27.2 micromol/L (26.0-110.8 micromol/L) and the tHbgo was 89.3+/-45.6 micromol/L (26.5-195.9 micromol/L). The correlation coefficient among the three methods were tHbg and tHbgo r=0.736; tHbo and tHbgo r=0.938; tHbg and tHbo r=0.598. A multiple regression with variable selection by Mellow's C(p) showed, that tHbg was correlated to the birthweight, the postnatal age, the heart rate and the pCO2 (r(2)=0.588), tHbo and tHbgo were associated with the hemoglobin concentration in the blood, the mean arterial blood pressure and the pCO2 (r(2)=0.493 and 0.406, respectively). The three methods (tHbg, tHbo, and tHbgo) give systematically different tHb readings and large intersubject variability.     

Ein Vergleich der Glucose-, Ketonkörper- und Glycerinspiegel im Nabelschnurblut und im Placentarblut

Zusammenfassung 1. Die Bestimmung von Ketonkörpern, Glucose und Glycerin getrennt in Nabelartcrie, Nabelvene, Placentararterie und Placentarvene ergab für Glycerin und Ketonkörper im Placentarblut meist etwas höhere Werte als im Nabelschnurblut.2. Es folgt daraus, daß es nicht zulässig ist, aus experimentellen Gründen Placentarblut an Stelle von Nabelschnurblut zu verwenden.3. Durch die Analyse der möglichen Ursachen kamen wir zu dem Schluß, daß es sich bei diesen Veränderungen wahrscheinlich um eine Widerspiegelung des placentaren Stoffwechsels handelt. Hämodynamische Einflüsse jedoch sind nicht auszuschließen.4. Es ist möglich, daß der Vergleich von Placentarblut und Nabelschnurblut unter normalen und pathologischen Bedingungen zum Studium des Stoffwechsels der Placenta in situ einen Beitrag liefern kann.

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Summary 1. The separate determination of ketone bodies, glucose and glycerol in umbilical cord artery and vein, placental artery and vein resulted in elevated levels of glycerol and ketone bodies in placental blood compared to cord blood.2. It is concluded that for experimental purposes cord blood is not to be replaced by placental blood.3. In analysing the possible facts we drew the conclusion that these results indicate a representation of the placental metabolism. Hemodynamic factors were not to be excluded, however.4. The comparison of placental with cord blood under normal and pathological conditions will possibly add to the study of placental metabolism in situ.

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Herrn Prof. Dr.G. Joppich zum 65. Geburtstag gewidmet.

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Die Arbeit wurde von der Deutschen Forschungsgemeinschaft unterstützt (Wo 69/7).

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Stipendiat der Alexander von Humboldt-Stiftung, 1967/68.     

Imaging mitochondrial redox environment and oxidative stress using a redox-sensitive fluorescent protein.

Redox-sensitive green fluorescent protein (roGFP) is a fluorescent protein in which two cysteines are placed adjacently in the barrel structure. Disulfide formation (oxidation) increases the absorption at short wavelengths (410 nm) at the expense of absorption at longer wavelengths (490 nm). The fluorescence ratio indicates reduction/oxidation, i.e., the redox potential at specific cellular locations.     

Divergent regulation of vascular endothelial growth factor and of erythropoietin gene expression in vivo

There is accumulating evidence from in vitro experiments that the gene expression of the vascular endothelial growth factor (VEGF) is, like that of the erythropoietin (EPO) gene, regulated by the oxygen tension and by divalent cations such as cobalt. Since the information about the regulation of VEGF gene expression in vivo is rather scarce, this study aimed to examine the influence of hypoxia and of cobalt on VEGF gene expression in different rat organs and to compare it with that on EPO gene expression. To this end male Sprague-Dawley rats were exposed to carbon monoxide (0.1% CO), hypoxia (8% O₂ ) or to cobalt chloride (12 and 60 mg/kg s.c.) for 6 h. mRNA levels for VEGF- 188, -164, and -120 amino acid isoforms in lungs, hearts, kidneys and livers were semiquantitated by RNase protection. For these organs we found a rank order of VEGF mRNA abundance of lung >> heart > kidney = liver. EPO mRNA levels were semiquantitated in kidneys and livers. Hypoxia, CO and cobalt increased EPO mRNA levels 60-fold, 140-fold and 5-fold, respectively, in the kidneys, and 11-fold, 11-fold and 3-fold, respectively, in the livers. None of these manoeuvres caused significant changes of VEGF mRNA in lung, heart or kidneys. Only in the livers did hypoxia lead to a significant (50%) increase of VEGF mRNA. These findings suggest that, in contrast to the in vitro situation, the expression of the VEGF gene in normal rat tissues is rather insensitive to hypoxia. In consequence, the in vivo regulation of the VEGF and the EPO genes appear to differ substantially, suggesting that the regulation of the VEGF and EPO genes may not follow the same essential mechanisms in vivo. Received: 31 July 1995/Received after revision: 20 November 1995/Accepted: 27 November 1995     

Computer-assisted image analysis of nucleolar organizer regions (NORs): a pilot study of astrocytomas and glioblastomas.

Computer-assisted image analysis was used to measure nucleolar organizer regions (NORs) of 22 astrocytomas and glioblastomas. Image analysis provides reproducible information about number and size of NORs together with further karyometric data, which can be compared and processed with other patient-related data. Our study exhibits a statistical relationship between number and size of NORs and malignancy of the measured gliomas.     

Multiple congenital anomalies/mental retardation (MCA/MR) syndrome due to interstitial deletion 1q

A severely retarded male infant was found to have a previously undescribed multiple congenital anomalies/mental retardation (MCA/MR) syndrome including microdolichocephaly, prominence of metopic suture, coarse scalp hair, epicanthus, anteverted nostrils, micrognathia, posteriorly angulated malformed auricles, preaxial hexadactyly, clinodactyly, camptodactyly, hypospadias, cryptorchidism, inguinal hernias, agenesis of left kidney, and pyloric stenosis. This syndrome was due to an interstitial del(1)(q25.2q31.2) associated with a paracentric inv(1)(q31.2q44).     

Changes in glutamate-related enzyme activities in the striatum of the rat following lesion of corticostriatal fibres

Summary The behaviour of enzymes putatively involved in glutamate/aspartate transmitter metabolism (glutamate dehydrogenase, aspartate aminotransferase, alanine aminotransferase,-glutamyltranspeptidase) was studied in the striatum 3, 7, 14 days and 7 weeks after mechanical destruction of corticostriatal fibres. For a period of up to seven days after unilateral lesion, enzyme activities were significantly diminished (by up to 13% based on protein) in the ipsilateral striatum as compared to the striatum of the intact side. Later, the enzyme activities in the ipsilateral striatum recovered. After seven weeks, an increase was observed for glutamate dehydrogenase activity, whereas the activity of alanine aminotransferase showed a transient rise at the end of the second week. The decrease in enzyme levels is interpreted as being attributable to the destruction of nerve endings which are considered to be glutamatergic, interfering with various compensating processes (e.g. glial cell proliferation) which occur with advancing times after lesion.     

The ''M2'' electromyographic response to random perturbations of arm movements is missing in long-trained monkeys

Post-trial injections of norepinephrine, but not dopamine, into the amygdala produce a long-term retention deficit (amnesia) for a 1-trial footshock experience in rats. In contrast, post-trial injections of dopamine, but not norepinephrine, into the caudate produce long-term facilitation. The data provide evidence for brain region-neurotransmitter specificity which supports a multiple component hypothesis.