bluuebunny/crossref_metadata_2025_split huggingface dataset:
The formation and mineralization of dentin
Authors: Bevelander Gerrit , Nakahara Hiroshi 
Published: February 2005

AbstractObservations were conducted at the light and electron microscope level of the formation and mineralization of dentin. At the light level it was shown that predentin is made up of the odontoblast process, collagen fibers and a ground substance. As mineralization occurs, the fibers tend to condense and thicken in areas adjacent to the odontoblast process. Fibers continue to invade the developing matrix and, as in early dentinogenesis, they appear at all times to be derived from the pulp.At the E.M. level the significant observations made in reference to dentin formation consist of the identification of granular masses appearing in the interfibrillar spaces initially in the region of the dentino enamel junction. Histochemical tests at the E.M. level demonstrated that the odontoblasts elaborate an acid mucopolysaccharide which concentrates in granules at the base of the odontoblast process. Subsequently these granules are extruded into the matrix where the polysaccharide becomes concentrated in the interfibrillar spaces and to come extent on the collagen fibers. The onset of mineralization occurs in the patches of mucopolysaccharide, later also on the fibers. It appears that the presence of an acid mucopolysaccharide is a prerequisit for mineralization in the dental matrix.
A variation in the plasma membrane of intestinal epithelial cells
Authors: Hampton J. C. , Rosario B. 
Published: February 2005

AbstractA modification of the plasma membrane of intestinal epithelial cells consisting of an apparent thickening of the inner lamella of the unit membrane is described. The evidence indicates that the thickening can be attributed to a piling‐up of stainable, granular material along the inner surface of the plasmalemma. Similar granules could be found in the cytoplasm, mostly in the region of the terminal web, and in mitochondria. Cells showing these changes were usually devoid of ribosomes and contained many smooth surfaced cytoplasmic vesicles.
The heart weight and ventricular weights of normal adult albino rats
Authors: Krames Barbara B. , Van Liere Edward J. 
Published: February 2005

AbstractThe heart weight as well as the heart weight‐body weight ratios of 264 adult albino rats, 155 males and 109 females were analyzed. The large rats have significantly heavier hearts than small rats, but small adults have on the average significantly higher heart weight‐body weight ratios than large adults.The heart was partitioned and the ventricle weight‐body weight ratio was also determined. As would be expected boty the right and the left ventricles are heavier in large rats than in small rats. However, the small rats have on the average a significantly higher ventricle weight‐body weight ratio than large animals.Since there are highly significant differences between the weight of the heart of large and small animals, if heart weights are used in experimental work, rather than heart weight‐body weight ratios, the animals should have a narrow body weight range.It is thought that these data may be helpful to those who work on the heart of the rat.
Penile spines of the domestic cat: Their endocrine‐behavior relations
Authors: Aronson Lester R. , Cooper Madeline L. 
Published: February 2005

AbstractThe post‐natal development of penile spines, their appearance in adult males, and the changes that occur in them after castration, after treatment of castrated males with testosterone propionate, and after cessation of hormone treatment were studied using both pre and postpuberal castrates. Most of the observations were made on live animals and the conditions of the spines were correlated with levels of sexual activity using data from mating tests with estrous females. In all the conditions of testing, the spines increased in size as the androgen level increased, and decreased in size as the androgen level fell. These changes correlated positively with the rise and depression of mating activity as the androgen levels increased or decreased. The relationship, however, was not always consistent in that sexual behavior declined rapidly in some castrated males before the spines started to decrease in size, and in other castrated males, sexual behavior persisted long after the spines had disappeared. While our data are not inconsistent with the hypothesis that loss of spines leads to reduced stimulation of the penis during intromission and hence to a decline in sexual arousal, it emphasizes that the great variability in sexual behavior after castration must be due to other causes.
Specificity of testosterone and estradiol in the differentiating neonatal rat
Authors: Feder Harvey H. 
Published: February 2005

AbstractThose components of sexual behavior characteristic of the adult intact male such as intromission and ejaculation, were inhibited in males receiving estradiol dipropionate within the first week of life. Neonatal treatment with testosterone propionate at corresponding ages did not disrupt the capacity for homotypic behavior when the males became adult. The expression of female behavior during adulthood was suppressed in female rats treated during a critical period of early postnatal life with testosterone propionate or estradiol dipropionate.Spermatogenesis was suppressed in males receiving the estrogen but not the androgen in early postnatal life, whereas ovulation was suppressed in females receiving the estrogen or androgen at corresponding periods.It was concluded that testosterone is compatible with the normal development of male sexual characteristics but that estradiol is not compatible with development of female sexual characteristics when administered during a critical period of differentiation. The specificity for androgen in adult males is postulated to be partly due to the presence of androgens during the critical period. The specificity for estrogen shown by females in adulthood is thought to be dependent upon the absence of estrogen and androgen during a corresponding developmental stage.
A double replication of a “small‐sample” study of the sexual behavior of DBA/2J male mice
Authors: McGill Thomas E. 
Published: February 2005

AbstractThe sexual behavior scores of three different groups of DBA/2J male mice, run at different times of the year, in two different places, and by different observers, were compared. Of 46 comparisons, two revealed statistically significant differences. It was hypothesized that one measure (% Move) was subject to much environmentally determined variation, while for the other measure (III), the significant difference may have been due to sampling error.Furthermore, substitution of the data resulting from either replication for the data of the DBA/2J males of the original study did not result in any changes as regards significant differences in sexual behavior among DBA/2J, C57BL, and BALB/c male mice. The results, in general, supported the hypothesis that intensive study of a small sample from an inbred strain would yield replicable results.
Sexual behavior patterns in the prepubertally castrate rat
Authors: Lisk R. D. , Suydam A. J. 
Published: February 2005

AbstractPrepubertally castrate female rats are capable of showing the lordosis response when given replacement therapy with female sex steroids, regardeless of age at which the ovaries are removed post birth, or when replacement therapy is commenced after adulthood. Estrogen alone is reraly a sufficient stimulus for behavioral estrus. Therefore the natural physiological trigger for estrous behavior in the rat is likely estrogen plus progesterone. Prepubertally castrate male or female rats never showed any male or female behavior following androgen implant in the brain. All rats castrated on day three or ealier, and given implants of estrogen plus progesterone in the preoptic hypothalamic area displayed the lordosis response. Thus the female sex response pattern is present in both sexes in the absence of gonadal hormones from birth. Brain development in the male castrate at birth does not appear to be identical to brain development in the female castrate at birth because a number of males showed the complete male sexual response pattern plus the female response pattern following neural implant of estrogen plus progesteron. The genotypic male thus appears to possess the information necessary to produce the neural connections for male and female sexual response patterns. Androgen acting at birth disrupts the development of the feminine response pattern so that the adult male ordinarily displays only the copulatory pattern.
Relationships of leydig cell characteristics and intratesticular testosterone levels to sexual activity in the African elephant
Authors: Buss Irven O. , Johnson Oscar W. 
Published: February 2005

AbstractHistological characteristics of testis tissues from 25 African elephants (Loxodonta africana) collected in Uganda, showed no consistent relationships among the following variables: Leydig cell size, cytoplasmic characteristics, and abundance; testicular testosterone content; and age. From these findings, plus field observations of sexual behavior, emerges the hypothesis that individual cyclicity in Leydig cell function was inherent in the elephant population studied. Testosterone content of testes from 32 elephants (including the 25 studied histologically) suggested that lone bulls were not of a senile nature since they contained relatively large quantities of testosterone and were relatively young (from about 12 to 25 years of age). Also, lone bulls were observed searching out estrous females. Among bulls collected from family units and herds, testosterone levels and behavior differed conspicuously. Behavior appeared to be directly related to testosterone content in several instances. Nonaggressive behavior among members of bull herds, plus the high proportion of such aggressive behavior among members of bull herds, plus the high proportion of such individuals with low testosterone content, suggest that some of these animals were in a depressed phase of sexual activity whereas others were undergoing pubertal development.
Variability in body and organ weights in the newborn dog and cat compared with that in the adult
Authors: Latimer Homer B. 
Published: February 2005

AbstractBody and organ weights of 24 newborn dogs and 35 newborn cats were studied. All of the measurements, except weights of hypophysis, spinal cord and testes are larger in the dogs. As percentages of body weight, the organs are more equally divided, with seven organs relatively heavier in the dogs and eight in the cats. All except two of the measurements of the newborn dogs are more variable than in the newborn cats.All of the organs are significantly correlated with body weight in the dogs and all except one, in the cats. All 15 of the organs are significantly correlated with body length in the dogs and 13, in the cats. The intercorrelations of the organ weights are somewhat higher in the dogs.The coefficients of variation of the newborn are compared with similar coefficients in adult dogs and cats. Body weight, body length and the kidneys are more variable in the adult dogs and the other organs, so far as data are available, are more variable in the newborn dogs of both sexes. Seven organs are more variable in adult male cats and three in females. The newborn dog is more variable in body and organ weights than the newborn cat, but weights of body and organs are better correlated in the newborn dog than in the newborn cat.
Perilymphatic fibrocytes in the vestibule of the inner ear
Authors: Hamilton David W. 
Published: February 2005

AbstractA description is given of the fine structure of perilymphatic fibrocytes and their associated fibers in the vestibule of the inner ear in rats. The identification of the extracellular fibers as keratin is discussed in relationship to their fine structure and to biochemical and biophysical data of other workers. The numerous junctional complexes between fibrocytes are described and it is shown that these do not form zonula occludens as has been reported by other workers.
Daily rhythmic variations in blood coagulation times in rats
Authors: Scheving Lawrence E. , Pauly John E. 
Published: February 2005

AbstractWith all other environmental factors rigidly standardized, normal Sprague‐Dawley rats were maintained under the following schedules: (1) 12 hours of artificial light 0600 to 1800 alternating with 12 hours of darkness‐LD; (2) reversal of the first‐DL; (3) constant darkness‐DD, and (4) constant illumination‐LL.After the animals had been under a specific lighting regimen for at least three weeks, blood coagulation times were determined on separate groups of 8 to 16 animals at bi‐hourly intervals during a 24‐hour period. Significant daily fluctuations or rhythms in coagulation times under all lighting conditions were found by plotting each of the bi‐hourly mean values as a function of time. The temporal phasing of all rhythms in LD, DL, LL and DD were similar. The major changes found in the different lighting schedules involved overall magnitude, e.g., the overall 24‐hour mean coagulation time for rats maintained in LL was 21% greater than for rats maintained in DD. Although total adrenalectomy or adrenal medullectomy did not abolish the characteristic LD rhythm, there was about a 100% decrease in the mean 24‐hour coagulation time of LD adrenalectomized animals when compared to normal LD animals. No significant decrease was seen in adrenal demedullectomized animals when similarly compared with normal LD animals.
Induction of partial limb regeneration in Rana pipiens by galvanic stimulation
Authors: Smith Stephen D. 
Published: February 2005

AbstractForelimbs of small adult frogs (Rana pipiens) were amputated and the stumps implanted with silver‐platinum bimetallic rods insulated except at the tips. The silver end was at the wound surface in some cases. In others, the platinum end was distally placed. Other animals received separate implants of short pieces of bare silver and platinum wire, with the silver piece placed near the wound surface. Controls consisted of animals with either no implant or implants of partially insulated silver or platinum wire.Only one of the control animals (one with a silver implant) initiated regeneration. Regeneration was minimal with the separate implants (25%), more frequent with the platinum end of a bimetallic couple at the wound surface (70%), and most frequent (83.4%) with the silver end of a bimetallic couple at the wound surface. In three cases in the last named series, lobulated cartilages reminiscent of wrist and hand elements differentiated. The results are ascribed to direct stimulation of the cells, electrophoretic transfer of information‐bearing molecules, or stimulation of nerves.
Some new cytological observations of the normal rat ependymal cell
Authors: Hirano A. , Zimmerman H. M. 
Published: February 2005

AbstractThe ependyma of the lateral ventricle of normal adult rats fixed by intravascular perfusion with either glutaraldehyde or formaldehyde was examined with the electron microscope. Three main observations of the normal ependymal cells were made which, to our knowledge, have not yet been reported.
Ependymal cells were occasionally found directly abutting on blood vessels in the immediate vicinity. In this respect, they were very much like the well‐known perivascular astrocytes and tanycytes. This similarity was strengthened by the morphological details of the junctional areas.
Bundles of the fine fibrils (app. 60 Å) were seen in the nuclei. They were devoid of any membranous boundary and were apparently identical to the fibrils often seen in the perinuclear cytoplasm.
Microtubules, occasionally containing approximately 50 Å central densities, were consistently seen in the apical cytoplasm. They were apparently identical to the familiar microtubules constituting the cillary fine structure which also contained occasional central densities.
Pituitary basophils of the Syrian Hamster: An electron microscopic investigation
Authors: Dekker Andrew 
Published: February 2005

AbstractHistochemical studies have not clearly defined the types or distribution of bascphils in the hamster's adenohypophysis. Electron microscopy is used in these experiments as a more accurate method for identifying types of basophils. Electron microscopic fields from regional areas of the gland were systematically photographed, and cell types counted. Hypertrophy of the appropriate basophils was observed in response to gonadectomy and thyroidectomy. FSH cells are oval, are adjacent to vascular spaces, have vesiculated endoplasmic reticulum and contain secretory granules measuring 200 mμ maximally. ICSH cells have filigreed cytoplasm, irregular cell borders, and secretory granules measuring 200 mμ maximally. TSH cells are polyhedral, have sparse endoplasmic reticulum, and secretory granules measuring 100 mμ maximally. The three basophilic cell types are randomly distributed throughout the gland.
The tensile properties of single osteons
Authors: Ascenzi Antonio , Bonucci Ermanno 
Published: February 2005

AbstractThe ultimate tensile strength and modulus of elasticity of individual osteons from human and ox compact bone were determined with a specially designed microwave extensimeter. The results were related to the degree of calcification and the orientation of collagen fiber‐bundles in successive lamellae of the osteons. The following conclusions were made: (1) When osteon specimens are dried, their tensile strength and modulus of elasticity increase, while their percent elongation under tension falls. (2) In the osteon samples tested wet, the degree of calcification induces an increase in the modulus of elasticity with additional amounts of calcium salts. (3) The modulus of elasticity in tension of the organic matrix corresponds to that of collagen. (4) In the osteons having a marked longitudinal arrangement of bundles of fibers in successive lamellae, the ultimate tensile strength and modulus of elasticity seem greater and the percentage elongation under tension seems lower than in osteons whose bundles in successive lamellae change through an angle of about 90°. (5) The tensile properties of osteons seem independent of the age of the subject. (6) Human and ox osteons reveal the same tensile behavior. (7) The tensile stress‐strain curves show that, even at the level of single osteons, bone behaves like a complex material, which, according to Sedlin, can be represented by a Hooke body linked in series to a Kelvin body.
The ontogeny and growth of the human tentorium cerebelli
Authors: Klintworth Gordon K. 
Published: February 2005

AbstractThe ontogenetic pattern of the human tentorium cerebelli was reconstructed by analyzing the series of stages through which the tentorium passes in the attainment of maturity. The absolute and relative growth rates were calculated for the maximum cranial breadth, maximum cranial length, and various tentorial dimensions. The relationship between the growth of different parameters was established and expressed mathematically according to Huxley's formula (y = bxk). The growth ratios (k) and constants (b) for different combinations of tentorial and cranial parameters were elicited from logarithmic graphs.
An autoradiographic study of chondrocyte transformation into chondroclasts and osteocytes during bone formation In vitro
Authors: Crelin E. S. , Koch W. E. 
Published: February 2005

AbstractExcised mouse pubic bone rudiments were exposed to H3‐thymidine. Rudiments preserved immediately after exposure consisted of mesenchyme with a large number of cells showing intense radioactivity. Rudiments incubated on a filter membrane after exposure went through the developmental stages of complete chondrification of the pubic rami followed by periosteal and then endochondral bone formation. Only chondrocytes showed radioactivity in rami consisting of cartilage and periosteal bone that were preserved prior to endochondral ossification. Cell types showing radioactivity in rami preserved during endochondral ossification were chondrocytes, chondroclasts, and osteoblasts and osteocytes of endochondral bone. The results of the study demonstrated that hypertrophic chondrocytes of the calcified cartilage of a developing mammalian long bone not only survive dissolution of their matrix, but transform into chondroclasts and osteoprogenitor cells that give rise to osteoblasts and osteocytes which form endochondral bone in the absence of blood vessels.
Studies of the luteotropic and mammotropic factor found in trophoblast and maternal peripheral blood of the rat at mid‐pregnancy
Authors: Matthies Donald L. 
Published: February 2005

AbstractBioassay data demonstrate that trophoblastic elements of the midpregnancy rat placenta contain a substance or substances possessing luteotropic and mammotropic properties. This material is also present in high potency in maternal serum but only at midpregnancy. The standard bioassay animal preparation utilized in demonstrating these properties was the immature, PMSG‐stimulated, hypophysectomized female Long‐Evans rat. The end point for detection of luteotropic activity was the deciduoma reaction and that for detection of mammogenic activity was proliferation of locally treated mammary parenchyma. The local injection of one day 12 placental equivalent daily for seven days consistently induced deciduoma formation and mammary parenchymal proliferation. Similar responses were observed in animals injected with 0.1 ml serum from peripheral blood of the day 12 pregnant rat.These biological extracts also possessed lactogenic activity, which was demonstrated by mammary secretory response to trophoblastic extracts and midpregnancy serum containing prednisolone acetate in suspension. Assay animals used in detecting this activity had been hypophysectomized, ovariectomized, and adrenalectomized.The pigeon crop sac responded weakly and tibial epiphyseal cartilage failed to respond to large doses of the biological extracts. No target organs other than the corpus luteum and mammary gland were found. It is proposed that an appropriate designation for this hormone would be Rat Chorionic Mammotropin (RCM).
The vascular architecture of the small intestinal mucosa of the monkey (Macaca mulatta)
Authors: Reynolds David G. , Brim Jack , Sheehy Thomas W. 
Published: February 2005

AbstractSilicone rubber microvascular injection compounds have been used to describe the mucosal vascular architecture of the monkey's small intestine. The mucosal vascular patterns of this animal differ from the classical description. Instead of the villus blood supply being delivered via a central villus arteriole, the arterioles ramify to the undersurface of the mucosa where they terminate in the capillary plexus surrounding the crypts of Lieberkuhn. The villus capillary net is derived directly from the cryptic capillary plexus and is drained by a single, central villus vein. There is a secondary venous return system that directly drains the cryptic plexus. These secondary venous channels might represent a mechanism that regulates the proportional distribution of blood in the cryptic and villus capillary beds.This report is intended to describe the vascular patterns only as they occur in the monkey. Observations of rat and rabbit mucosa prepared by the same technique reveal arterial and venous channels extending the length of the villi. These animals, therefore, more closely resemble the classical description.