Seminal vesicle formation and specific male protein secretion by female cells in allophenic mice.

The relation of cellular sex genotype to phenotype was examined in seminal vesicles of adult allophenic mice with cellular sex chromosome mosaicism. Each animal originated from conjoined blastomeres of an embryo of female (XX) and one of male (XY) constitution, from different inbred strains. Cells of both sexes were detected in bone marrow and certain other somatic tissues; cellular sex of seminal vesicles was deduced from strain-associated electrophoretic variants of proteins coded for at autosomal loci. Seminal vesicles composed partly or entirely of female cells were found in male and pseudohermaphrodite individuals. In a pseudohermaphrodite, both allelic variants of the tissue-specific normal male seminal vesicle protein (Svp-locus) were present, signifying that female as well as male cells were synthesizing the protein. Male-determining factors on the Y chromosome are thus not required in cells that differentiate into functional seminal vesicles.

A method for determination of fractal dimensions of sialographic images.

A method for measuring the fractal dimension of radiographic images was devised by the modified pixel dilation (PD) method, and its accuracy was examined by two types of image analyzers: one controlled by a minicomputer and based on the hexagonal array of the pixels, and the other controlled by a personal computer and based on the square array of the pixels. It was shown that the fractal dimensions measured by using the image analyzers for three curves (straight line, Koch curve, and Sierpinski gasket) were deviated by less than 2.1% from the theoretical dimension. The time required for the measurements fell within 10 seconds by the minicomputer-controlled image analyzer, and within 12 minutes by the personal computer-controlled image analyzer, which contrasts to the 30 minutes or more required for measuring fractal dimensions by other available methods. Analysis of the ductal patterns in sialograms by this method indicated that the fractal dimensions were significantly different between normal parotids and parotids with Sjögren syndrome. The modified PD method can be used for measuring the fractal dimension of ductal patterns in sialograms. The measurements may serve as numerical gradings of the progression of disease.

Fractal dimensions of ductal patterns in the parotid glands of normal subjects and patients with Sjögren syndrome.

RATIONALE AND OBJECTIVES: The sialographic ductal patterns of the parotid glands in patients with Sjögren syndrome were compared with those of normal patients by measuring the fractal dimensions. METHODS: Fractal dimensions were estimated using the modified pixel dilation method. RESULTS: The mean fractal dimension was 1.64 +/- 0.06 for the normal glands and 1.39 +/- 0.10 for the glands with Sjögren syndrome (P < .005). No correlation between the age or sex and fractal dimension was observed for both groups. In Sjögren syndrome, a significant difference in the fractal dimension was observed between the subgroup having punctuate fillings with a diameter less than 1 mm and the subgroup from 1 to 2 mm (P < .001). CONCLUSION: The fractal dimension is useful as a numeric grading of the complexity of the ductal pattern and the progression of parotid disease.

Sialographic images of pathological changes in the mouse parotid gland.

In order to correlate pathological changes of mouse parotid glands with their sialographic images, we conducted studies on mice with known pathological changes: mice with Stensen's duct ligated, NZB mice with a systemic auto-immune disease, and aged mice. The sialographic images were found to be specific for the pathological changes: The glands after ligation of Stensen's duct were characterized by dilated, large excretory ducts with a reduced system of peripheral ducts; the glands of NZB mice showed lobular leakage of the contrast medium from small excretory ducts; and the glands of aged mice showed a great reduction in the ductal system. It is concluded that sialography yields useful information on the pathological changes of the ductal systems in the mouse parotid gland.

Chromosome activities in cleaving mouse embryos to construct prenucleolar bodies orienting an intranuclear chromosome-chromosome configuration.

Most chromosomes of cleaving mouse embryos formed spherical structures called as prenucleolar bodies. Embryos stained with fluorescing dyes selective for AT-rich regions of DNA indicated that chromosome centromeres were organized by prenucleolar bodies and that chromosomes at pre-prophase of the cleavage division started to condense with their centromere regions aligned towards the peripheries of spheres. Embryo chromosomes as well as prenucleolar bodies were shown to bind a monoclonal antibody to spliceosomal snRNAs, which are contrasted to the nucleoli or chromosomes of somatic cells. More than 10 prenucleolar bodies were found in the pronuclei at the earliest stage after fertilization and 40 of them at most, diploid number of chromosomes of the mouse, in the nuclei of the 2-cell embryos. The number was decreased later in the cell cycles and at the 4-cell stage. Hence, every chromosome of cleaving mouse embryos is highly active in constructing prenucleolar bodies and behaves during the interphase until mitosis as a unit of the body; either as a single unit or as a member of the units fused. In other words, the prenucleolar bodies function as centers orienting chromosome-chromosome configuration in the fertilized eggs.

Radiosensitivity variation during the cell cycle in pronuclear mouse embryos in vitro.

The radiosensitivity of pronuclear mouse (B6D2 F2 X ICR) embyros has been measured in vitro as a function of time during the cell cycle. This was done by measuring the dose of X-rays (LD50) required to prevent development of 50% of the pronuclear embryos to the blastocyst stage in 5 days of culture. The LD50 was found to vary from 1 to 2 Gy during the period from G1 to the first cleavage. The cell cycle in the pronuclear embryo was analysed by [3H]thymidine autoradiography. Compared with earlier studies on two-cell mouse embryo radiosensitivity, the pronuclear embryos appear to be more sensitive to radiation than the two-cell embryos. If, however, one considers the radiation sensitivity on a blastomere basis, the pronuclear embryos are not different in their radiation sensitivity from the two-cell embryos. Thus, during the early cleavage stages of mice, radiosensitivity is mainly governed by the content of cells of various cell cycle ages in the embryo.

Factors involved in the high radiographic sensitivity of E-speed films.

A microscopic and densitometric analysis of the high speed and fog density of E-speed film was conducted. The grain sizes of silver bromide (AgBr) and developed silver metals were measured, and the optical densities of the film were compared by means of various development procedures. Silver bromide grains were found to be large and accounted for the high speed of the film. Development caused chains of silver metal clusters to form, which contributed to the larger fog density as well as the higher speed.

Postnatal development of the duct system in the mouse parotid gland.

The morphology of the parotid gland in adult mice is mouse strain-specific. C57BL/6 and C3H/He strains of mouse are representatives of two types of the morphology identified previously. The postnatal development of such morphologic differences was investigated by sialography of excised glands of these strains of mouse. It was observed that the mouse strain-dependent morphological characteristics were already present at birth, except for the branching pattern of the peripheral duct system, which became differentiated at 3 weeks of age. These results indicate that the C3H/He mouse-specific branching pattern of the peripheral ducts reflects the profile of matured secretory units and ducts, and that the C57BL/6 mouse-specific pattern resembles that of an immature C3H/He mouse.

Modulation in protein phosphorylation during G2 phase of the cell cycle in two-cell mouse embryos.

The protein phosphorylation activities in extracts were assayed for 2-cell mouse embryos at three stages of the G2 phase of the cell cycle. The 2-cell embryos were unique in having a prolonged G2 phase and so easily staged at early G2 (EG2), middle G2 (MG2) and late G2 (LG2) by timing the embryo isolation from pregnant mice. The embryo extracts were used both as sources of protein kinases and their substrates. The phosphoproteins of the extracts were labelled with [gamma-32P]ATP and separated by electrophoresis on SDS-polyacrylamide gels. The present study revealed that protein phosphorylation increased 3-6-fold during the progression of 2-cell embryos from EG2 to LG2 and the level of protein phosphorylation at any stages was greatly decreased by the presence of cAMP. Thus, the protein phosphorylation system of 2-cell mouse embryos seems to differ from those reported systems in mammals in its negative dependence on cAMP.

Induction of proliferating cell nuclear antigen (PCNA) complex formation in quiescent fibroblasts from a xeroderma pigmentosum patient.

Accumulated evidence indicates that proliferating cell nuclear antigen (PCNA) is an auxiliary protein of DNA polymerase delta and forms tight association with DNA replication sites during DNA replication or DNA repair synthesis. In this study, such PCNA complex formation was investigated by the indirect immunofluorescence method, using both normal human fibroblasts and those derived from a xeroderma pigmentosum group A (XP-A) patient. XP-A fibroblasts in both proliferating and quiescent states did not show any differences from normal fibroblasts in the properties of PCNA-staining in the untreated conditions. The PCNA complex formation was induced in quiescent normal fibroblasts by both ultraviolet light (UV)- and X-irradiation, whereas in XP-A fibroblasts it was induced by X-irradiation, but not by UV-irradiation. However, PCNA complex was induced in quiescent XP-A fibroblasts by UV-irradiation when the cells had previously incorporated 5-bromodeoxyuridine (BrdU). These observations indicate a close correlation of PCNA complex formation and unscheduled DNA synthesis (UDS). Thus, it was concluded that PCNA complex formation was commonly induced in at least three conditions to produce UDS in spite of different types of DNA damages and DNA repair mechanisms.