Esterification of cholesterol and cholestanol in the whole body,tissues, and frass of Heliothis zea

The quantity of free and esterified sterols in the whole body, intestine, hemolymph, fat body, and frass of 6th-instar larvae of H. zea, fed cholesterol or cholestanol, was measured in order to determine if there was a difference in the utilization of these two molecules. The principal sterol in the tissues of the larvae was cholestanol or cholesterol, when they were fed diet containing these two molecules, respectively; there was little, if any, metabolism of dietary cholestanol to cholesterol. There was little or no difference in the amount of total sterol in the whole body, tissues, or frass of larvae fed the two different diets, indicating that the absence of a Δ⁵-bond in cholestanol does not prevent the uptake or distribution of this sterol to various tissues. However, the relative percentage of steryl ester was significantly higher in prepupae reared on a diet containing cholestanol instead of cholesterol (6–7-, 4-, 13-, 4-, and 2-fold increase, for the whole body, intestine, hemolymph, fat body, and frass, respectively). The average percentage of total sterol that was esterified in the tissues was greater in the fat body (10.8 ± 15.4 and 44.2 ± 12.3%, respectively, for larvae fed cholesterol and cholestanol) than in the hemolymph (0.5 ± 0.1 and 6.3 ± 0.8%) and intestine (1.2 ± 0.1 and 4.7 ± 1.1%). The percentage of sterol that was esterified in the frass of larvae was large (26.9 ± 3.7 and 48.2 ± 0.5%, respectively, for larvae fed cholesterol and cholestanol). Therefore, the fact that larvae of H. zea fed cholestanol, instead of cholesterol, contain this saturated molecule as their principal tissue sterol and preferentially esterify it may explain, at least in part, why their rate of growth on cholestanol is slower than on cholesterol.     

Cytochrome c/H2O2-mediated one electron oxidation of carcinogenic N-fluorenylacetohydroxamic acids to nitroxyl free radicals

The oxidation of carcinogenic hydroxamic acids, N-hydroxy-N-2-fluorenylacetamide (N-OH-2-FAA) and N-hydroxy-N-3-fluorenylacetamide (N-OH-3-FAA) catalyzed by horseradish peroxidase (HRP) or cytochrome c in the presence of H2O2 was investigated. HRP/H2O2 was a more efficient system in oxidation of both hydroxamic acids and the standard substrate, guaiacol, then cytochrome c/H2O2. Peroxidative activity of cytochrome c was shown after incubation with Triton X-100 and H2O2 for 20 min at room temperature in 0.05 M phosphate buffer (pH 7.5) or in 0.1 M sodium acetate (pH 6.0) without Triton X-100. Both hydroxamic acids were oxidized to nitroxyl free radicals as shown by electron spin resonance (ESR) spectroscopy. These radicals dismutated to equimolar amounts of 2- or 3-nitrosofluorene and acetate esters of the corresponding hydroxamic acids as shown by thin layer chromatography and spectrophotometric analysis of the products. In addition, large amounts of the N-fluorenylamides were generated in the reactions with cytochrome c/H2O2 system. Of the products, only 2- or 3-nitrosofluorene per se or when generated from the oxidation of the hydroxamic acids, interacted with lecithin (1 mg/ml) to yield ESR signals of the immobilized nitroxyl free radicals. In contrast to HRP/H2O2 system, in which the initial velocity of the radical formation was too fast to measure and the maximal concentrations of the nitroxyl free radicals of both hydroxamic acids were similar, in the cytochrome c/H2O2 system the nitroxyl free radical of N-OH-2-FAA formed at a 6-fold faster rate and accumulated at a 2-fold higher concentration than the radical of N-OH-3-FAA. In both enzyme systems, the persistence of the signal and the length of time before it had decreased to one half its maximum were several-fold longer for the nitroxyl free radical of N-OH-3-FAA than for that of N-OH-2-FAA. These data showed that these nitroxyl free radicals differed in their kinetic properties. One electron oxidation of N-OH-3-FAA by HRP/H2O2 system and of both isomeric hydroxamic acids by cytochrome c/H2O2 system are reported for the first time in this work and may be considered an activation reaction in carcinogenesis by these compounds.     

46,XX/46,XY chimerism in a phenotypically normal man

Summary Some twenty cases of dispermic chimeras with the karyotype 46,XX/46,XY, discovered because of gonadal dysplasias or a true hermaphroditism, have been reported. This is a report of a phenotypically normal man with 46,XX/46,XY chimerism in whom a prepubertal finding of positive X-chromatin was interpreted as Klinefelter syndrome. The diagnosis was revised 11 years later when the family doctor, who doubted the earlier diagnosis because of the patient's normal-sized testes, sent him to an outpatient clinic. The young man was 23 years old, athletic (74kg, 180cm), with normal body proportions, normal sexual hair distribution, normal libido and potency, normal endocrine parameters, and a normal spermiogram. The karyotype revealed an XX/XY mosaic in a proportion of 1:2. An identical set of maternal markers (Q- and C-banding) was present in male and female cells. Differences were found with respect to two paternal markers. Furthermore, blood, serum, and red cell enzyme groups in five systems showed two phenotypes, again with duality of paternal origin. It is concluded that a positive X-chromatin in prepuperty, especially in the absence of supporting clinical features, must be followed by a karyotype study.     

Development of lung tumors in Syrian hamsters with a mixed Mycoplasma pneumoniae and influenza virus infection

The authors studied morphological alterations in the lungs of Syrian hamsters infected intranasally with Mycoplasma pneumoniae and influenza virus. The animals were first infected with M. pneumoniae and after 7 days with influenza A/PR8 virus. On days 1-3 after infection with influenza virus (days 8-11 following infection with M. pneumoniae) the animals showed the appearance of multiple foci of bronchiolar epithelium proliferation. At the later stages of experiment the size of the foci of proliferation increased. On days 14-21 after infection with influenza virus (days 21-28 of experiment) the animals developed lung tumors.     

Zur formalen Genetik der Phosphoglucomutasen (EC: 2.7.5.1); Untersuchung von 366 Familien

Summary The polymorphism of PGM₁ has been investigated in a series of 366 families from Southwestern Germany with 676 children. The segregation of the children's phenotypes is in agreement with the formal genetic model.

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Mit Unterstützung durch die Deutsche Forschungsgemeinschaft.