摘要:

AbstractData were collected from a colony of 49 male and 55 female two‐year‐old Mongolian gerbils,Meriones unguiculatus(Milne‐Edwards, 1867). This report gives tables which present data regarding linear measurements of body and organs and absolute and relative organ‐weight data. The means, standard deviations, ranges, and coefficients of variation were summarized in the tables. Grossly observed pathological organs were omitted from the study. The tables give information about this species which could be helpful in future laboratory investigations where the body‐and organ‐weight ranges, variability and linear measurements of this species may be of prac

ISSN:0003-276X    

DOI:10.1002/ar.1091500402

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1964

数据来源: WILEY

摘要:

AbstractThe organized cartilaginous fibrous system which appears during growth of the fracture callus in traumatized femora was investigated in mice of five, 52 and 78 weeks of age. Histological preparations were stained with toluidine blue O and observed under polarized light using a first order red retardation plate.Development and organization of the cartilaginous fibrous system was similar in animals of all age groups studied, however, its time of appearance was dependent upon the time of appearance of cartilage cells and in association with these cells. Alignment of cartilage cells followed very closely after appearance of the fibrous system. Initial orientation of the fibrous system was almost perpendicular to the bone surface. As the system became more extensive the slope of fiber direction became less acute, pointing towards the fractured end of the shaft. Orientation of the fibrous system is believed to be a consequence of the forces set up during growth of the fracture callus, e. g., the force of the growing cell mass due to postfracture, active cell proliferation of the osteogenic layer of the periosteum and hypertrophy of cartilage cells and the tension placed on the fibrous layer of the periosteum in response to the events taking place below this tissue layer. The importance of the cartilaginous fibrous system is believed to lie in the early temporary support of the fracture fragments and the proper alignment of the cellular elements of the fracture, necessary for proper architectural reconstruction. Formation of the cartilaginous fibrous system was independent of the existing periosteal fibrous system.

ISSN:0003-276X    

DOI:10.1002/ar.1091500403

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1964

数据来源: WILEY

摘要:

AbstractAn anomaly of the termination of the aorta is described which is apparently unique. The aorta divided directly into two internal iliac arteries and two external iliac arteries.

ISSN:0003-276X    

DOI:10.1002/ar.1091500404

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1964

数据来源: WILEY

摘要:

AbstractMarginal bands from erythrocytes of several non‐mammalian vertebrates were studied by light and electron microscopy. Cells were observed in thin sections after various fixing procedures and in wholemount preparations. Isolated marginal bands were prepared by air drying and freeze drying. The marginal bands are composed of tubular elements which vary in diameter from 200 Å to 500 Å, depending on the preparation method. It is suggested that these tubules are part of a general class of microtubules, and that the real diameters of microtubules are approximately twice those observed in fixed and sectioned mater

ISSN:0003-276X    

DOI:10.1002/ar.1091500405

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1964

数据来源: WILEY

摘要:

AbstractA simple method leading to growth and mitosis in over 95% of shortterm cultures of lymphocytes from the blood, lymph or thymus of the rat is described. The method which is modified from Moorhead's original technique (′60) employs standard tissue culture medium (Eagles MEM or TC no. 199), 20% fresh rat serum, washed lymphocytes, penicillin, and phytohemagglutinin‐P (0.01 cm3/cm3of culture of a 1:5 dilution of stock solution). Details of culture technique and factors contributing to growth failures are discussed.The chromosomes of male and female Lewis rats were studied in metaphase spreads of cultured cells. The karyotypes of these rats are presented and found to be in agreement with those recently reported by Hungerford and Nowell (

ISSN:0003-276X    

DOI:10.1002/ar.1091500406

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1964

数据来源: WILEY

摘要:

AbstractStudies of the ultrastructure of the seminiferous tubule of the Swiss mouse have shown the external limiting membrane to consist of internal and external lamellae enclosing a single layer of flattened cells. Both lamellae contain fibers, probably collagenous, running parallel to the long axis of the tubule. Superficially, a layer of connective tissue cells covers the external lamella. The nucleus of the Sertoli cell is typified by irregularity of size and shape, electron density of the nuclear membrane, and characteristic nucleolus. The cytoplasm contains mitochondria with vesicular cristae, and irregular dense bodies of possible secretory origin. Cytoplasmic processes extend between the germinal cells and in certain areas their surfaces are marked by periodic accumulations of fine granules which present a picture suggestive of desmosomes.Two types of spermatogonia have been noted. One possesses a large spherical nucleus containing finely granular nucleoplasm and scanty cytoplasm. The second is characterized by an ovoidal nucleus containing numerous chromatin clumps and scattered nucleolar fragments. Primary spermatocytes exhibit the intercellular bridges and synaptinemal complexes characteristic of these cells. The spherical nuclei contain densely packed fine granules. The nuclei of secondary spermatocytes often exhibit centrally located clumps of chromatin material. Mitochondria appear vacuolated at low magnifications but high magnification micrographs show them to contain finely membranous cristae.

ISSN:0003-276X    

DOI:10.1002/ar.1091500407

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1964

数据来源: WILEY

摘要:

AbstractThe first statistically significant decline in the mean number of young born to female golden hamsters occurred in the fourth litters. The decreased size of fifth litters was highly significant and few females bore six litters.Hamsters unilaterally ovariectomized at 30 days of age had a significantly lower number of litters containing live young during their lifetime. Despite increased unilateral ovulaton, they bore less than half as many total young per female as intact controls and fetal resorptions and stillbirths occurred at an earlier age.The results of matings during the period of reproductive decline were observed in females from the age of ten months until death or sacrifice at an advanced age. Final litters contained few young, some born dead. One or two subsequent pregnancies were of term length but all conceptuses were resorbed. Few females beyond 15 months of age had implantation sites and most of these resorbed. Regular four day estrous cycles continued until a terminal illness and matings resulted in pseudopregnancy. Blastocysts were found at four and one‐half days of gestation in some old females but not at 6 to 8 days. Failure of implantation appeared to be due to an inadequate uterine decidual reaction in the old animals.It appeared from the above observations that decreasing uterine adaptability limited reproductive capacity in aging hamster

ISSN:0003-276X    

DOI:10.1002/ar.1091500408

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1964

数据来源: WILEY

摘要:

AbstractOva were removed from donors 63‐68 hours after ovulation and placed in the uteri of pseudopregnant recipients of the same pregnancy age. In transfers of ova from young (2 1/2‐6 month) to old (14–18 month) golden hamsters, only 8.3% developed into term fetuses. From old donors to young recipients, 4.5% of ova developed to term fetuses. In transfers of ova from young donors to young recipients, 49.2% of ova developed into term fetuses. There was no significant difference in percentage of fetal development between the two groups containing old females. The difference between these and the control (young to young) group was highly significant.There was a significantly lower number of ova recovered from old donors. At time of transfer, over one‐sixth of the ova from old donors consisted of only one to four cells. At seven and one‐half days, embryos developing from ova of old donors in uteri of young recipients were retarded and malformed.It is concluded that while the uterine environment in old hamsters appears inadequate to foster normal fetal development, there are also fewer ova ovulated in old females and these ova more frequently develop a

ISSN:0003-276X    

DOI:10.1002/ar.1091500409

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1964

数据来源: WILEY

摘要:

AbstractRudimentary cilia were found on fibroblasts of a human brain tumor examined in the electron microscope. These cilia apparently have their origin in the centrioles of the fibroblasts; both centrioles appear to be involved in formation of cilia in most instances observed. Because of their atypical appearance and confinement by adjacent cell processes, it is unlikely that these cilia can perform any useful motor function for the cell. The cilia may serve as an expression of the morphogenetic potential of centrioles.

ISSN:0003-276X    

DOI:10.1002/ar.1091500410

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1964

数据来源: WILEY

摘要:

AbstractCastrated and castrated and hypophysectomized female mice (BALB/c) were injected subcutaneously with estradiol‐17β (0.5 μg or 1.0 μg/day) and progesterone (1.0 mg or 3 mg/day) in addition to prolactin (1.0 mg), oxytocin (1.0 IU) or growth hormone (1.0 mg), alone and in combination for 10 or 15 days. Twenty‐four hours after the last hormonal treatment, tritiated thymidine (0.7 μc/gram body weight) was injected intravenously, and the mice sacrificed six hours later. Tissue from the inguinal mammary glands was removed and processed for radioautographic, histological and whole mount study.Radioautographs of hematoxylin stained sections of mammary tissue from each animal were selected. Under oil immersion, 2,000 epithelial cells were consecutively counted and the number of labeled cells noted. Results are expressed as the per cent of labeled epithelial cells.All hormonal treatment, except oxytocin alone, caused a significant increase in per cent of labeled cells as compared to castrated, untreated animals. The per cent of labeled cells depended, in general, on the dosage and duration of treatment. Combinations of growth hormone with estradiol‐17β and progesterone did not augment epithelial proliferation. The addition of oxytocin or prolactin to the estradiol‐17β (0.5 μg) — progesterone (1.0 mg) combination significantly increased the per cent of labeled cells.Prolactin, but not oxytocin, augmented epithelial proliferation in similarly treated castrated and hypophysectomized mice. Combinations of estradiol‐17β (1.0 μg) and progesterone (3.0 mg) with oxytocin or prolactin did not significantly augment epithelial proliferation as compared to ovarian ste

ISSN:0003-276X    

DOI:10.1002/ar.1091500411

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1964

数据来源: WILEY