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391.
Allele frequencies of 14 different restriction fragment length polymorphisms from 12 DNA markers within the Huntington disease (HD) region were evaluated in the German population. No significant differences from published data of allele frequencies from chromosomes of Caucasian ancestry were found. The analysis of eight DNA polymorphisms in 87 HD families of German origin revealed significant non-random association with the HD locus and the D4S95 locus (p674/AccI/MboI), a result that is consistent with all other published studies. These results are confirmed by the fact that the HD gene maps to this region. 相似文献
392.
Automatic classification of chromosomes as part of a routine system for clinical analysis 总被引:2,自引:0,他引:2
A procedure for automatic classification of G-banded human chromosomes has been implemented on a semiautomated system for routine clinical analysis. Chromosomes represented by their density profiles are described by so-called weighted density distributions (WDDs) by application of a number of weighting functions and classified by a parametric discriminant analysis. During 16 mo of routine use of the system, 2,794 metaphases (127,925 chromosomes) from amniotic fluid have been karyotyped by the system with an error rate of 8-9%. This corresponds to 4-5 errors per metaphase. These errors can immediately be corrected by the operator on a displayed karyogram with a light pen. 相似文献
393.
Sprague-Dawley rats were exposed to ethyl alcohol in utero. The effect of chronic prenatal exposure was examined by giving mature females alcohol in isocaloric liquid diets which served as the sole source of liquid and caloric intake before mating and throughout gestation. Controls consisted of females maintained on laboratory chow or an isocaloric liquid diet minus alcohol before and during gestation. The offspring were sacrificed at 21 days of age (weanlings) and the hearts dissociated enzymatically to give purified cardiac myocytes. The effects of daily acute prenatal alcohol exposure were studied by gastric intubation of alcohol to chow-fed females for the duration of pregnancy. The doses used approximated 4 and 5 shots of 80 proof liquor per day by a person weighing 150 lb. These offspring were sacrificed at 2, 6, and 21 days postnatal and cardiac myocytes prepared as above. Heart weights were determined and cardiac myocytes were analyzed for cell length, volume, cross-sectional area, and percent binucleation. Additionally, nuclear DNA content was measured in all of the 21 day offspring. Statistical analysis of the data showed no significant differences between hearts exposed to prenatal alcohol and nonexposed controls with either regimen with the exception of percent binucleation which was significantly but only slightly higher in the 6-day-old hearts. These findings are discussed in relation to anatomical heart defects found in patients with full fetal alcohol syndrome. 相似文献
394.
Summary Since the advent of green-fluorescent protein (GFP) technology there has been an explosion of interest in applying this molecule
to cell biology. This review summarizes new insights in secretory membrane traffic obtained by the use of GFP fusion proteins.
Transport steps between the endoplasmic reticulum and the Golgi apparatus, intra-Golgi traffic, and transport from the Golgi
to the plasma membrane are discussed. In addition, insights into the dynamics of the Golgi compartment in plant cells and
in mitotic mammalian cells have been included. We conclude that membrane traffic in the secretory pathway appears to be much
more dynamic and diverse than previously thought and that GFP promises to be a powerful means to unravel these complex processes. 相似文献
395.
Ib Christian Klausen Lars Ulrik Gerdes Erik Berg Schmidt Jørn Dyerberg Ole Faergeman 《Human genetics》1992,89(4):384-388
Summary Previous studies in Greenland suggest that death rates from ischemic heart disease [IHD] are lower in Eskimos than in Danes and other Caucasian populations. This has been explained by a high intake of n-3 polyunsaturated fatty acids with beneficial effects on blood lipids and hemostasis. In other populations, lipoprotein(a) [Lp(a)] is associated with IHD, plasma concentrations of Lp(a) being genetically determined to a major extent. We have compared Lp(a) concentrations and apo(a) phenotypes in 120 Greenlandic Eskimos with those in 466 Danish men. The median Lp(a) concentration in Eskimos (8.7mg/dl;[95% CI 6.5–10.7]) was not significantly different from that in Danes (6.3mg/dl; [95% CI 5.2–7.0]), whereas the 90th percentile was significantly higher among Danes: 46.36mg/dl; [95% Cl 43.0–54.3] vs. 27.6mg/dl [95% CI 20.7–36.9]. In 20% of the Danes, but in only 8% of the Eskimos (P = 0.009), the concentration of Lp(a) exceeded 30mg/dl. The difference is probably explained by a low frequency of the low molecular weight apo(a) phenotypes among Eskimos, since the apo(a) isoforms F and B were absent, and the S1 and S2 types were present in only 3.3% of Eskimos. In contrast, these apo(a) isoforms were present in 26.6% of the Danes in either single-band or double-band phenotypes. The pattern of apo(a) polymorphism found in this study could provide part of a genetic explanation for the putative low rates of IHD in Eskimo populations. 相似文献
396.
397.
A. K. Nielsen P. Thorsted T. Thisted E. G. H. Wagner K. Gerdes 《Molecular microbiology》1991,5(8):1961-1973
The gene systems srnB of plasmid F and pnd of plasmid R483 were discovered because of their induction by rifampicin. Induction caused membrane damage, RNase I influx, degradation of stable RNA and, consequently, cell killing. We show here that the srnB and pnd systems mediate efficient stabilization of a mini-R1 test-plasmid. We also show that the killer genes srnB' and pndA are regulated by antisense RNAs, and that the srnC- and pndB-encoded antisense RNAs, denoted SrnC- and PndB-RNAs, are unstable molecules of approximately 60 nucleotides. The srnB and pndA mRNAs were found to be very stable. The differential decay rates of the inhibitory antisense RNAs and the killer-gene-encoding mRNAs explain the induction of these gene systems by rifampicin. Furthermore, the observed plasmid-stabilization phenotype associated with the srnB and pnd systems is a consequence of this differential RNA decay: the newborn plasmid-free cells inherit the stable mRNAs, which, after decay of the unstable antisense RNAs, are translated into killer proteins, thus leading to selective killing of the plasmid-free segregants. Thus our observations lead us to conclude that the F srnB and R483 pnd systems are phenotypically indistinguishable from the R1 hok/sok system, despite a 50% dissimilarity at the level of DNA sequence. 相似文献