PubMed Health⌕ Search

Biomedical subjects

L Henke

Publications and source records attributed to L Henke.

31 records · Page 2Linked to original sources
PubMed1995

Recent observations in human DNA-minisatellite mutations.

We report maternal and paternal mutation rates at loci D1S7 (MS1), D7S21 (MS31), D12S11 (MS43A), and D7S22 (G3). The respective mutation rates were as follows: [table: see text] At loci D7S21, D12S11, and D7S22 statistically significant differences in mutation rates exist between the sexes. No such difference was observed at locus D1S7. However inspection of the latter data reveals that by mutation at spermiogenesis approximately two-thirds of the fragments showed an addition of repetitive units, while a 50: 50 ratio was encountered in the series of maternal mutations. We also report the observation of naturally occurring 3-fragment patterns.

Adult↗
PubMed1993

DNA-minisatellite mutations: recent investigations concerning distribution and impact on parentage testing.

At least 815 meioses were studied in the HinfI polymorphisms of DNA minisatellite loci D1S7, D2S44, D7S21, D7S22, and D12S11 in order to collect data on respective mutation rates. At locus D7S21 (probe MS31) a striking difference between the paternal and maternal mutation rate was observed (1.5% versus 0.2%). This study also describes, how to deal biostatistically with paternal mutations in parentage testing. Possible implications of mutations are illustrated by the description of 2 cases. Case 1 reports an "exclusion" of mother and father with probe MS1. Case 2 describes 2 paternal "exclusions" with probes MS31 and G3. The statistical likelihood for a paternal "exclusion" with 2 of the 5 probes is 0.13%. By omitting probe MS1, this frequency can be reduced to 0.02%. Nevertheless, the second case clearly shows, that informative blood group markers cannot be replaced by DNA polymorphisms.

Alleles↗
PubMed1992

Biostatistical basis of individualization and segregation analysis using the multilocus DNA probe MZ 1.3: results of a collaborative study.

A collaborative study using the multilocus minisatellite DNA probe MZ 1.3 was carried out to investigate segregation information, mutation rate, DNA fragment frequencies as well as band sharing characteristics. The fingerprint patterns of 393 children as well as 694 unrelated individuals were analysed after digestion of DNA with the restriction enzyme HinfI. A mutation rate of 1% per meiosis or 0.04% per band was found with a mean number of 26 bands/individual. It was shown that maternal and paternal fragments are inherited in equal proportions. Population frequencies of restriction fragments demonstrated a distribution with increasing frequencies in the small fragment size range below 10 kb as well as the absence of very common or very rare fragments. Our data can be used to calculate simple exclusion probabilities based on the number of non-maternal bands in the child.

Biometry↗
PubMed1992

Pathologic explanation for hypoechoic halo seen on sonograms of malignant liver tumors: an in vitro correlative study.

OBJECTIVE: The purpose of this study was to evaluate the morphologic substrate of the hypoechoic halo seen on sonograms of malignant liver tumors. MATERIALS AND METHODS: We used sonograms and pathologic examinations to evaluate 17 cadaveric livers with macroscopic tumors (three primary liver tumors, 14 metastases). During sonography (3.5 and 5.0 MHz), a representative section plane was marked, and the same section was examined histologically. Emphasis was placed on the architecture of the tumor and the morphology of the periphery of the tumor that could account for the hypoechoic halo seen on sonograms. RESULTS: In 13 of 17 hepatic tumors, a hypoechoic halo was detected on sonograms. Histopathologic examination showed an intratumoral rim consisting of proliferating tumor cells in 12 cases and an extratumoral rim of compressed liver parenchyma in all 13 cases. A detailed comparison of sonographic and histopathologic findings showed that the hypoechoic halo corresponded to a greater concentration of tumor cells and areas of less marked fibrosis and necrosis in the periphery of the tumors. This occurred in 11 cases. In one case, histologic studies showed that the hypoechoic rim was caused by compressed liver parenchyma. In another case, the hypoechoic halo was caused by intratumoral (cellular peripheral zone of tumor) and extratumoral (compressed liver parenchyma) components. All four tumors without a halo at sonography were uniform histologically. CONCLUSION: The sonographic halo seen on sonograms of malignant liver tumors seems to be caused predominantly by a zone of proliferating tumor in the periphery of the lesion.

Adenocarcinoma↗
PubMed1991

Population genetic data determined for five different single locus minisatellite probes.

We report on the population genetic data (frequencies of restriction fragments, heterozygosity rates, and mutation rates) obtained by analysis of approximately 1100 Hinfl-digested DNAs from West Germans. Probe G3 detects a common 1.7 kb DNA fragment showing a population frequency of about 13%. All the other fragments detected with probes MS1, MS31, MS43, G3 and YNH24 show frequencies of less than 8%. These data suggest that single locus DNA probes can provide valuable information for parentage evaluation and individualization.

DNA Probes↗
PubMed1990

BamHI polymorphism of locus D2S44 in a West German population as revealed by VNTR probe YNH24.

BamHI polymorphism at the VNTR locus D2S44 was investigated, concentrating on band frequencies, mutation rate and confirmation of Mendelian inheritance. In this series 39 restriction fragments showing frequencies less than 10% could clearly be distinguished. No mutations could be observed and the Mendelian character of inheritance is beyond reasonable doubt.

Blood Group Antigens↗
PubMed1990

[Use of DNA polymorphism in forensic paternity evaluation].

Problematical paternity cases were additionally subjected to DNA-polymorphism analysis. 5 cases are reported, focusing on problems due to, 'silent' allele transmittance, relatively low probability for paternity, obvious occurrence of the extremely rare Rh gene complex CWc, involvement of brothers as putative fathers, non-paternity of a man although his W-value was 99.975%. The aim of this paper is to demonstrate the need for DNA-polymorphism analysis, if conventional blood group tests do not lead to a clear-cut decision. Extended typing of conventional blood group polymorphisms (except HLA) cannot compete with highly polymorphic DNA loci.

Adult↗
PubMed1988

Comparison of different X-ray films for 32P-autoradiography using various intensifying screens at -20 degrees C and -70 degrees C.

The amplifier effect of different intensifying screens on commercially available X-ray films was tested in autoradiography with 32P at -20 degrees C and -70 degrees C. For the films X-Omat AR, RX and HR-G in combination with the screens G 12 and Lgy-S 600, there was no significant enhancement of blackening at -70 degrees C compared with -20 degrees C. Therefore exposure at -20 degrees C is generally feasible, if an appropriate film-screen combination is used.

Adenosine Triphosphate↗
PubMed1980

Photodestruction of acetylcholinesterase.

Ultraviolet irradiation of 11S acetylcholinesterase (acetylcholine acetylhydrolase, EC 3.1.1.7) produces a loss of tryptophan fluorescence which is best described as the sum of two separable first-order processes, one much more rapid than the other. In addition, the enzyme undergoes an all-or-none inactivation that is monotonically first order. Simultaneous with activity loss, photoscission takes place and results in a molecular weight drop of 1 x 10(5); this decrease is first order with a rate constant identical to that for enzymatic inactivation. These processes are accompanied by apparent conformational changes, as shown by circular dichroic and difference absorption spectra. The relative photochemical inactivation efficiency of incident light is unity when corrected for the wavelength dependence of fluorescence excitation, which is consistent with an efficient Förster resonance transfer of energy among the aromatic chromophores. The extreme sensitivity of acetylcholinesterase to photodestruction upon photon absorption and the several events that follow it not only suggest that these findings might be a basis for a useful molecular probe of the structure of this enzyme, but also indicate that additional care should be taken when conducting spectroscopic studies in the UV region.

Acetylcholinesterase↗
PubMedDate not supplied

Size calculation of restriction enzyme HaeIII-generated fragments detected by probe YNH24 by comparison of data from two laboratories: the generation of fragment-size frequencies.

Restriction fragment-length polymorphism of locus D2S44 detected by the highly polymorphic probe YNH24 and restriction endonuclease HaeIII can be used to improve parentage testing when representative fragment-size frequencies can be obtained. By joining the results of different laboratories, it is possible to set up a meaningful databank. Therefore, the same randomly chosen samples were tested for the HaeIII RFLP detected by probe YNH24 in Düsseldorf (DUS) and Amsterdam (AMS). The results of the different fragment-size calculations obtained by using internal markers and a computerized system (DUS-cad and AMS-cad), and by using external markers and manual calculations (DUS-man), were analyzed. Comparing these results, no statistically significant differences were seen. The results obtained with probe YNH24 and enzyme HaeIII in Düsseldorf and Amsterdam can be used to attain a sufficient number of samples to generate relevant fragment-size frequencies.

DNA↗
PubMedDate not supplied

[Significance and testimonial value of hemo-genetic legal identification with special reference to DNA analysis].

175 hemogenetic expertises on the identity of ostensibly jumbled blood samples were analysed. In 4.5% of the cases a genetically qualified non-identity was found, although an erronous mixing-up of samples could be excluded. A major problem may arise when the expert witness has to find out whether a non-identity is due to either genetic or to artificial reasons. A battery of conventional blood group systems as well as highly informative DNA polymorphisms is a powerful tool in discriminating between both reasons and enables the expert to reach a decision.

Alcoholic Intoxication↗