bluuebunny/crossref_metadata_2025_split huggingface dataset:
Observations on the early events of cadmium necrosis of the testis
Authors: Chiquoine A. Duncan 
Published: February 2005

AbstractA light and electron microscopic study of the early changes which occur in cadmium necrosis of the testis of the mouse was made in an effort to identify the site of action of cadmium. Mice were given a single, intraperitoneal injection of 1% CdCl2 at a dosage of 0.1 ml/10 g body weight and then the testes were fixed for light and electron microscopy at various hourly intervals. The earliest changes which were appreciated by light microscopy consisted of an edema of the intertubular spaces, congestion of blood vessels, and an increased amount of granular precipitate in the connective tissue spaces. By electron microscopy the earlies changes were observed in the endothelium of the testicular vascular bed and consisted of a striking and rapid increase in the prevalence of pinocytotic vesticles suggesting an increased interchanges of fluid between the blood and extravascular spaces. All of these changes preceded any appreciable alteration in the cells of the seminal epithelium. The fact that the earliest alterations are observed in blood vessels suggests that the site of action of cadmium in the production of testicular necrosis is upon the endothelium of the vascular bed.A comparative series of animals (frog, pigeon, rooster, armadillo, opossum) was also investigated as to their susceptibility to the toxic effects of cadmium. the results from these species, and other species reported by previous investigators, suggest the generality that cadmium necrosis is a phenomenon common to species possessing scrotal testes and absent from those possessing abdominal testes. The opossum is an exception to this generality. These findings are discussed in relation to the blood supply of the testis.
Cadmium‐induced injury of the rat testis
Authors: Mason Karl E. , Brown James A. , Young James O. , Nesbit Robert R. 
Published: February 2005

AbstractIt is well known that cadmium chloride administered as single, subcutaneous, sub‐toxic doses selectively damages the rat testis, producing irreversible injury of the germinal epithelium and temporary damage to the interstitial tissue.Studies reported here demonstrate that: (1) this injury represents an ischemic necrosis secondary to rapid production of intertubular edema (4 to 6 hours), increased intratesticular pressure, with or without associated hemorrhage, and ultimate interference with testicular blood supply and drainage – not unlike injury following testicular artery ligation; (2) as dosage is progressively reduced to approximately one‐sixth that employed by most investigators, interstitial tissue is unaffected and ischemic necrosis is supplanted by a non‐necrotic degeneration of the germinal epithelium closely resembling, in its histopathology and irreparability, that occurring after vitamin E deficiency; (3) oral administration of vitamin E has no protective effect, and testes of rats critically depleted of E show no increased susceptiblity to cadmium.Observations on the nature and distribution of tubular injury, and on the vasculature of the testis and epididymis, suggest that the unusual sensitivity of the testis to cadmium is related to unique features of its vasculature; namely, the pulseless, semistagnant flow of blood in the intratesticular course of the testicular artery, which permits cadmium to alter capillary endothelium permeability, causing edema and pressure effects leading to acute anoxia at higher levels of dosage, and diminishing degrees of anoxia with decreasing dosage levels. Comparable morphological features of the proximal segment of the caput epididymis make it likewise susceptible to cadmium injury.
The influence of temperature on skeletal maturation of hypothyroid rats
Authors: Hamburgh Max , Lynn Edward 
Published: February 2005

AbstractThe rate of skeletal maturation as indicated by ossification of bony elements of the central and appendicular skeleton was compared in two groups of hypothyroid young rats, raised at 20°C and 30°C constant environment respectively.Hypothyroidism was induced by feeding 0.2% propylthiouracil mixed with the food in powdered form to pregnant rats starting on the fifteenth day of gestation and continuing this treatment to the suckling mother until their litters had reached weaning age.The appearance of epiphyseal centers, of carpal and tarsal centers, middle phalanges and femoral and tibial processes and caudal vertebrae 7–27 is delayed in hypothyroid newborn rats over that of normal controls. Hypothyroid rats raised at 20°C lag more severely behind the controls with respect to skeletal maturation, than do hypothyroid rats raised at 30°C. The latter are intermediate or in some instances their rate of skeletal maturation resembles that of the control group.The possible significance of the demonstration of diminished requirements for thyroid hormone by the developing rat for studies attempting to identify mechanisms of hormone action in development is briefly discussed.
Cholinesterase distributions in the rat epididymis and vas deferens after castration and sex hormone treatments
Authors: Risley Paul L. , Skrepetos Chris N. 
Published: February 2005

AbstractCholinesterase (ChE) distributions in the epithelial and smooth muscle cells and in the peripheral nervous plexus of the reproductive ducts of the male rat are dependent on male sex hormones. Castration results in establishment of a low maintenance level of apical enzyme activity in the epithelial cells; smooth muscles and the nerve plexus of the vas deferens and cauda epididymidis also show reduced enzyme reactions. Testosterone treatment restores the normal enzyme relations in the epithelium and smooth muscles. Estradiol is partially effective, but reaction intensities do not attain normal distrbutions and proportions. Reductions in relative numbers of ChE positive nerve plexus fibers and their enzyme reactivity, and recession to outer muscle layers occur in castrates, but better recoveries follow after testosterone than after estradiol treatments. The results are interpreted to be in agreement with other data relating to smooth muscle behavior and its neural and hormonal regulation. Epithelial cell differentiation is complete in testosterone treated castrates, but is incomplete in estradiol treated cases, although ChE synthesis and duct growth occurs in the latter.
Histochemical studies on developing mast cells
Authors: Burton Alexis L. 
Published: February 2005

AbstractBy means of a new staining procedure (using a mixture of Astra blue and safranin O), studies on the polysaccharides of the mast cell granules were made in adult and embryonic connective tissues of the rat. According to their staining reactivity toward these dyes, it was found that, in the adult tissues, mast cells can be classified into three groups: (1) Astra blue positive mast cells, or “blue” cells; (2) safranin positive mast cells, or “red” cells, which are the most numerous cells; (3) intermediate forms, which exhibit affinity for both dyes, or “mixed” cells. In the embryo, mast cells appear first on the fifteenth‐sixteenth day of development as small round cells, the cytoplasm of which contains flakes of Astra blue positive material; rapidly, this material becomes granular, and on the twenty‐first day (just before birth), a large mast cell population exists in the subcutaneous connective tissue of the embryo, containing only cells of the “blue” type. Eight to 15 days after birth, “red” and “mixed” cells are visible. Progressively, the mast cell population becomes of the adult type. It is thought that these variations in the staining reactivity correspond to the evolution of the cell: the “blue” forms are the younger cells and the “red” forms are the adult mast cells. This is probably related to a progressive increase of the number of strong acidic groups which are present in the polysaccharidic molecule.
Weight responses of tissue slices and albumin‐gelatin gels during formaldehyde fixation with observations upon the effects of pH
Authors: Bernard George R. , Wynn Gail G. 
Published: February 2005

AbstractThin slices of rat liver, kidney, and M. rectus femoris and thin, flat pieces of albumin‐gelatin gels (which approximated the tissue slices in mass, dimensions and protein content) were immersed in formalin solutions at various concentrations, in some cases with variable amounts of NaCl (0.11‐0.25M) added, and in some cases buffered at pH values ranging from 3.5–7.0. The slices were weighed at frequent intervals for the first 20 hours of immersion. Weight changes occurred rapidly. With the exception of the neutral buffered formalin curves, three families of response curves were obtained for the three tissues. With both formalin and formalinsaline solutions weight gain was inversely proportional to the solute concentration, but the formaldehyde particles apparently are not involved osmotically. The total osmotic concentration of formalin solutions, therefore, is not a factor in the swelling or shrinking of tissue slices. The presence of contaminants could be responsible for the effective osmotic concentration observed with these solutions. The weight response of slices is influenced by the pH of the formalin. Although the response of the gel system to any particular solution was quantitatively greater, it was qualitatively the same as the tissue slice response.
Histochemical contribution to the study of lysosomes in the rat spinal cord
Authors: Sharma Dharmvir R. , Matzke Howard A. 
Published: February 2005

AbstractVarious histochemical tests were performed to study the nonenzymatic components of lysosomes in the neurons of rat spinal cord. The lysosomal granules are periodic acid Schiff positive and this reaction can be blocked by acetylation, but not by bromination. They are performic and peracetic acid Schiff positive also. Both these reactions can be blocked by bromination. It is concluded that 1:2 glycol as well as ethylene groups are present. Lysosomes stain metachromatically after sulfation and are sudanophilic. They are chemical complexes containing protein, neutral polysaccharide, phospholipids and possibly glycolipids and are present in dendrites as well as axons. A topographical relationshiop exists between lysosomes and Golgi apparatus which was stained with nucleoside diphosphatase method. Lysosomes share Schmorl reaction with lipofuscin pigment. In some preparations there is a tendency for them to be localized along the cell membrane.
Neurosecretion in the hibernating bat. The morphology of the hypothalamo‐hypophyseal system
Authors: Troyer J. Robert 
Published: February 2005

AbstractThe morphology of the hypothalamo‐hypophyseal tract of 35 hibernating bats (Myotis lucifugus lucifugus) was studied in chrome‐alum‐hematoxylin‐phloxine‐stained serial coronal and sagittal sections. Vinyl acetate and wax‐plate reconstructions also aided in describing the two neurosecretory hypothalamic nuclei of this system. The most prominently defined nucleus, the supraoptic, consisted of a smaller portion rostral to the optic tract that was tenuously connected to a larger caudal portion. The probability that some of the posteriorly located cells of the caudal portion represent other hypothalamic nuclei is discussed. The shape and location of the paraventricular nucleus was more difficult to determine. Although the neurosecretory cells of this nucleus were similar in their irregular or eliptical shape to those of the supraoptic nucleus, the majority of the paraventricular cells were smaller and had less of an affinity for the chrome‐alum‐hematoxylin stain.The majority of CHP‐positive axons originating in the supraoptic nucleus converged toward the median eminence and terminated in the pars nervosa. Most of the axons from the paraventricular nucleus coursed laterally toward the supraoptic nucleus where they followed the pathway described from this nucleus. The localization of CHP‐positive material in the neurohypophysis is presented. Comparisons were made between the morphology of this system in the hibernating bat and that of other species of mammals reported in the literature.
Histopathology of dystrophic and normal mice after timed periods of parabiosis
Authors: Pope Richard S. , Murphy Edwin D. , West William T. 
Published: February 2005

AbstractTwo‐hundred and eight mice were paired as parabionts, or as single controls, with normal mice on the day of weaning. Pairs were sacrificed at 4, 8, 12 and 16 weeks after pairing. Autopsies were performed, organs were weighed and microscopic examination of tissues was performed. The results show a decreased liver weight in parabiosed dystrophics with a concomitant increased liver weight in parabiosed normals. The severity of muscle lesions of parabiosed dystrophics was less than that of counterpart single dystrophics. There was no observed clinical improvement.
The silver staining of reticular fibers by electrophoresis
Authors: Monroe Clyde W. , Harris R. G. 
Published: February 2005

AbstractIn this technique reticulin is stained black with silver by the electrophoretic method. Use Zenker or formalin (10%) fixed tissue, but mordant the latter in Zenker stock for one hour or longer‥ Carry paraffin sections to water; mordant, if necessary; wash well in tap water; transfer to distilled water; place slide in tray containing the ammoniacal silver solution; turn voltage regulator to a potential of 70 v; manipulate the electrodes by passing the negative one back and forth over the section and about 5 mm above it, one minute or less; both electrodes are of 20 gauge copper wire; dip in distilled water; reduce in 5% formalin, three minutes or more; rinse in tap water; to AuCl3, 1–5 minute rinse in tap water; into 5% Na2S2O3. 5 H2O, two minutes; dehydrate, clear, and mount in synthetic resin. This method was used on tissues obtained from human autopsies (liver, lung, scrotum, ovary, esophagus and suprarenal).
Fibrillar elements forming dentin and mineral seeding or crystal nucleation
Authors: Kiguel Enrique 
Published: February 2005

AbstractThere are two different types of fibrils contributing to the formation of the dentinal matrix; (1) a coarse type, (Korff's fibers), are the chief component of the first dentin formed next to the dentino‐enamel junction (mantle dentin), and (2) finer fibrils, which are the main component of subsequent layers of dentin next to the pulp tissue (circumpulpal dentin). It is known that Korff's fibers in developing teeth present both the morphological characteristics of collagen, that is, the 640 Aº banding, and argyrophilic staining properties which are typical of reticular fibers. Upon their transformation into fibers that exhibit both the morphological and staining properties of collagen, mineralization of dentin takes place. Since the Korff's fibers exhibit the 640 Aº banding from the very beginning of their formation and, therefore, prior to mineralization, it is notable that the 640 Aº banding is not critical for initial mineral seeding or crystal nucleation. The factors actually initiating mineralization seem to be chemical changes in predentin just prior to mineralization. The fibers lose their argyrophilic properties, alkaline phosphatase decreases, and a change occurs in the mucopolysaccharides associated with dental fibers.
Etiology of antenatal hydrocephalus induced by folic acid deficiency in the albino rat
Authors: Stempak Jerome G. 
Published: February 2005

AbstractWistar strain albino rats were fed a folic acid free diet with added folic acid antagonists (x‐methyl folic acid and 9‐methyl pteroylglutamic acid) for a 48‐hour period beginning on day 8 and ending on day 10 of gestation. The period of deficiency was terminated by an injection of 500 μg of folic acid in water. If the injection was not made, most animals resorbed their litters. Fetuses were excised from days 16 through 20, processed routinely, decalcified, if necessary, embedded in paraffin, serially sectioned, and stained. Newborns were treated similarly. Hydrocephalus was the only defect observed in the treated animals. The serial sections demonstrated an occluded or extremely stenotic aqueduct of Sylvius in every hydrocephalic animal examined. The stenosis was seen to be present as early as the sixteenth day of gestation, and occlusion was observed in 17‐day‐old animals. It is concluded that the defect predisposing to hydrocephalus induced by folic acid deficiency in this strain of rats is extreme stenosis or complete occlusion of the aqueduct of Sylvius.
Studies on the effect of trypan blue in the pregnant armadillo, dasypus novemcinctus
Authors: Ferm Vergil H. , Beaudoin Allan R. 
Published: February 2005

AbstractEvidence is presented that the hemochorial placenta of the ninebanded armadillo, Dasypus novemcinctus, is permeable to trypan blue when this dye is injected subcutaneously into the mother during the postimplantation period. This permeability appears to be related to a time‐dependent active process or is associated with the maturation of the fetal reticulo‐endothelial system. Spectrophotometric analysis of serum proteins revealed alterations in the dye‐injected mothers as well as in thalidomide‐treated animals as compared to untreated controls. While it is difficult at present to estimate the stage of pregnancy under teratogenic study, it is felt that this unusual experimental animal warrants further study with other teratogenic agents.
The effects of grafting during various stages of the hair growth cycle
Authors: Sanford Barbara H. , Chase Herman B. , Carroll Sarah B. , Arsenault Claudette T. 
Published: February 2005

AbstractGross and microscopic observations of graft and surrounding area were made after grafting during various stages of the hair growth cycle.All grafts were successful although temporary disturbance was observed when grafting was done during late anagen.Biopsies showed epidermal breakdown, even in telogen grafts, with repair being accomplished primarily by diversion of hair follicles to epidermal production. The later in anagen a graft was done, the less likely the follicles were to return to hair production later.Permanent loss of pigment was seen in some grafts, particularly those done in late anagen. Loss of pigment cells or their attachments from scraping the graft undersurface is a possible explanation, as is loss or damage to melanocytes while the follicles are producing epidermis.Delays and irregularities in hair growth cycles were also observed in host skin surrounding grafts. An explanation involving loss of inhibitor during grafting is proposed.The authors feel that hair growth activity in either donor or host is not an adequate explanation for graft rejection. It is also emphasized that hair growth is a poor criterion for graft survival.
Postnatal development of beta cells and ILA secretion in the pancreatic islets of the golden hamster
Authors: Sak Matthew F. , Macchi I. A. , Beaser Samuel B. 
Published: February 2005

AbstractFetal and neonatal endocrine pancreas of the golden hamster (Mesocricetus auratus) was evaluated cytochemically with regard to maturation of beta cell granulation (aldehyde fuchsin technique) and the structural findings were related to the release of insulin‐like activity (ILA) in vitro (rat epididymal fat pad bioassay).In the fetal pancreas 12 hours before birth, beta cells could not be distinguished histochemically although considerable ILA was released. In the absence of distinct islands of Langerhans at birth, a few cells showed AF+ granulation which was accompanied by a slight increase in the ILA. Maximal release of ILA occurred approximately on the second postnatal day when the AF+ granulation was denser and more abundant than at earlier periods. Beyond the second day, the rate of in vitro ILA secretion decreased although islets and beta cells showed progressive structural maturation. There was also a relative increase in the amount of exocrine tissue in the portions of pancreas used for bioassay. Advancing proteolytic inactivation may have accounted for the decrease in effective ILA when the latter was expressed per unit weight of tissue.The data indicate that in the golden hamster, beta cells are biochemically competent before they demonstrate cytochemical maturity.
The skin of primates XIX. The relationship between melanocytes and alkaline phosphatase‐positive cells in the potto (Perodicticus potto)
Authors: Kechijian Paul 
Published: February 2005

AbstractThe epidermis of the potto, which normally contains no DOPA‐reactive melanotic melanocytes, supports a population of large dendritic cells which are specifically reactive for alkaline phosphatase. After irradiation of the skin with ultraviolet light, these same dendritic cells become DOPA positive and produce visible melanin. These results give further evidence that the alkaline phosphatase‐reactive dendritic cells are part of a unique system of epidermal melanocytes.
Innervation and regeneration in orbitally transplanted limbs of Amblystoma larvae
Authors: Pietsch Paul , Webber Richard H. 
Published: February 2005

AbstractThere is a widespread belief that innervation is an indispensible requirement for regeneration in salamander limbs. Several independent investigations have indicated that this view is too rigid. In this laboratory it was observed that regeneration proceeds in orbitally transplanted limbs, but the signs of innervation are few when the tissues are stained with ordinary histological procedures. The present study was conducted to find out if orbitally transplanted limbs do, in fact, possess nerve fibers and if their presence is, indeed, required for regeneration to proceed.Forelimbs of Amblystoma larvae were transplanted to the orbit. In one series, transplants were amputated two weeks after transplantation. Amputated segments were stained with protargol and revealed very few signs of innervation. Nevertheless, regeneration proceeded and reached a typical outcome within the usual time required for completion of the process normally. Full‐term transplant regenerates exhibited innervation at levels of about one‐third of normal values.In another series of experiments, limbs were subjected to distal amputation either before or shortly after transplantation. Regeneration proceeded normally in these experiments providing that the transplant was rapidly vascularized. When vascularization was delayed or failed, regeneration was retarded or did not occur at all.These findings, taken in light of those of other works, suggest that the function of nerves under ordinary conditions may be assumed by other tissues under circumstances produced by transplantation. This in turn suggests that nerves influence regeneration in a generalized manner and that the specificity ordinarily associated with them may be quantitative rather than qualitative in nature.
A study of the inguinal region of the abdominal wall in female mice
Authors: Leppi T. John 
Published: February 2005

AbstractBilateral inguinal sacs or outpouchings of the abdominal wall normally occur in Brown‐belt stock female mice. The length of each sac was determined to be from the caudal border of the pubic symphysis or interpubic ligament to the caudalmost extension of the sac. Sacs of control animals usually exceeded 1.0 mm in length and were longer in intact and ovariectomized mice treated with implanted testosterone pellets. There were no viscera observed in any of the inguinal sacs of the mice in this study. The bilateral inguinal sacs appear to be homologues of the scrota of males. The alterations in sac length produced by testosterone treatment are believed to be the result of changes in the connective tissue components of the sac.