Search

A total of 941 mouse blastocysts obtained from two types of crosses in which one of parents carried Cattanach’s X/autosome translocation was studied cytogenetically by quinacrine mustard fluorescence. The rearranged X (Xt) and the normal X (Xn) were distinguished by size. Karyotype analysis was successful in 721 embryos, of which 205 were heterozygous for Cattanach’s translocation. A single heterochromatic and brightly fluorescent X chromosome was identified in 154 metaphase spreads from 89 blastocysts consisting of 32–96 cells. The paternally derived X chromosome (Xp) was heterochromatic in 87 % and 88 % of the informative cells from the crosses XtXn × XtY and XtXn × χnγ; respectively. This preferential choice of Xp at the blastocyst stage might have an important bearing upon the preponderance of cells with an inactive Xp in the chorion and yolk-sac splanchnopleure.

In the previous report, we discussed in vivo dynamics and renal impairment resulting from the difference in cisplatin CDDP administration. In the present study, we investigated in vivo dynamics and renal impairment under 1 h of continuous drip infusion of CDDP. The free-type Pt concentration ratio, which is considered to indicate antitumor activity in the overall plasma Pt concentration at the end of the administration, was noted to be approximately 64%. This was significantly higher than other administration methods, making this an effective administration procedure. However, NAG, which is considered to be an index of renal impairment along with the amount of beta 2-microglobulin urine excretion, showed higher values than those by other administration methods. Thus, using the 1-hr continuous CDDP drip infusion, we attempted to alleviate the renal impairment, combining bismuth subnitrate with ginseng and Tang-koui ten. As a result, the amount of beta 2-microglobulin excretion in the urine was diminished as well as NAG, and a reduction of the renal impairment was noted. These alleviational effects of the renal impairment were attributed to the method of consistent oral administration by which alleviation could take place with little load on the patient.

Four patients with various phenotypic stigmata of gonadal dysgenesis are presented. Cytogenetic investigation revealed each to be mosaic for 45 XO and 46 XO+ minute element stemlines. In two patients the additional element proved to be a small ring, and in the remaining two the supernumerary chromosome was a minute centric fragment. Autoradiographic studies indicated that the ring chromosomes were late replicating, while the metacentric fragments were not. The correlation of the autoradiographic behavior of these abnormal chromosomes with their possible origin is discussed, and a new hypothesis concerning the evolution of the XO karyotype is proposed.

A new type of stripe-geometry double heterojunction laser is proposed. The laser has internally striped planar (ISP) structure. The lateral current confinement is realized by using the difference of V-I characteristics between n-p-p-p and n-p-n-p structures. The ISP structure is made with both succesive solution growth techniques and selective diffusion techniques. Both near- and far-field patterns show single transverse-mode oscillation in the laser with 3-µm stripe width. The smallest active area of 2.5 µm (horizontal) × 0.6 µm (vertical) has been obtained. The transverse beam spreadbetween 50% peak intensity points is 30°. The polarization of laser emission is TE mode. The lowest threshold current obtained is 135 mA for the sample with 3-µm stripe width and 150-µm cavity length.

Some ultrasonic imaging systems with lens system for underwater use have been studied1,2,3. An ultrasonic imaging system utilizing a piezo-electric transducer array converter has been developed4.

Summary A sex-chromatin-positive female with secondary amenorrhea and minimal stigmata of gonadal dysgenesis is described. This diagnosis was confirmed by the observation of ‘streak gonads’ at laparotomy and histologic interpretation of rudimentary ovarian development. Cells cultured from peripheral blood, skin and gonadal tissues for cytogenetic evaluation exhibited an abnormal karyotype. The modal number was 46; however, only five normal chromosomes were found in group D (13–15). An abnormal submetacentric chromosome was also present. Morphologic, measurement and autoradiographic data suggest that the ‘marker’ chromosome represents a pericentric inversion of the sixth D-group member.

X-ray magnetic circular dichroism (X-MCD), i.e. the dependence of the absorption coefficient of circularly polarized X-rays on the projection of the magnetization in a ferromagnetic system onto the photon propagation direction, yields e. g. at L2,3 edges in transition metals large values up to 50%. In combination with a soft x-ray microscope where Fresnel zone plates as optical elements provide a lateral resolution down at 25nm, X-MCD can be used to image magnetic microstructures. This photon based technique allows for recording images in varying external magnetic fields, it exhibits inherent chemical specificity, a high sensitivity due to the large contrast and allows to distinguish between in-plane and out-of plane contributions. In this report the basic features of this novel technique will be outlined and results obtained with the XM-1 microscope at the ALS (Berkeley/CA) with thermomagnetically written bits in magneto-optical storage systems demonstrate the applicability of this new experimental technique to technological relevant issues.

Background: The aryl hydrocarbon receptor (AhR or dioxin receptor) is a ligand-activated transcription factor that is considered to mediate pleiotropic biological responses such as teratogenesis, tumour promotion, epithelial hyperplasia and the induction of drug-metabolizing enzymes to environmental contaminants usually represented by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). In contrast to the role of AhR in the regulatory mechanism of xenobiotic-metabolizing enzymes, there is no direct proof that the AhR is involved in the teratogenic effects of TCDD. Results: To gain insight into the physiological and teratogenic role of the AhR, we have used gene targeting in mice to disrupt the murine Ahr gene by homologous recombination. Ahr-null mice were viable and fertile and were apparently normal at birth, but displayed a slightly slower growth rate than wild-type mice for the first few weeks of life. When pregnant dams were administered with TCDD by gavage, at a dose of 40 μg/kg body weight at gestation day 12.5, none of the Ahr-null mutant foetuses were sensitive to the teratogenic effects of TCDD, although almost all wild-type foetuses suffered from cleft palate and hydronephrosis. In heterozygous Ahr+/− genotypes, nearly all foetuses suffered from hydronephrosis in response to TCDD treatment, while haplo-insufficiency was observed in the incidence of cleft palate. Conclusion: These results clearly show that the AhR is involved in the malformation of the palate and kidney in mouse embryos caused by TCDD and suggests that the mechanism of its involvement differs between the cleft palate and hydronephrosis.

Combining X-ray magnetic circular dichroism (X-MCD) with a transmission X-ray microscope (TXM) allows to image element-specifically magnetic domain structures with 25 nm lateral resolution. Both in-plane and out-of-plane systems can be studied in applied magnetic fields. Thus field-dependent parameters, as individual nucleation fields in magnetic nanostructures can be deduced and related to morphology. Images of thermomagnetically written bits in magneto-optical TbFeCo media proof the reliability of the writing process and the importance of an exact thermal design of the systems. Domains observed at corresponding Co L edges proof the chemical sensitivity of M-TXM and its potential to image few monolayer systems.

A new type of stripe-geometry laser is proposed. A very small lateral current spreading and a transverse single-mode oscillation are realized in this structure with a near-field pattern as narrow as 3 µm.

A magneto‐optical switch using a yttrium‐iron‐garnet crystal plate with phase matching films requiring a drive voltage of only 5V is demonstrated at 1.3 μm wavelength. Using a semihard magnetic material, we developed a bistable magneto‐optical switch which drives with a switching speed of 20 μs. An extinction ratio of 24 dB was obtained.