bluuebunny/crossref_metadata_2025_split huggingface dataset:
Tissue interactions between epithelium and mesenchyme of urogenital and integumental origin
Authors: Cunha Gerald R. 
Published: February 2005

AbstractTrypsin‐separated epithelia and mesenchyme were prepared from the following urogenital and integumental tissues of embryonic mice: seminal vesicle, urogenital sinus, preputial gland, and back, snout, and plantar surface foot plate skin. These components were rejoined in control (homotypic) and experimental (heterotypic) recombinants and were subsequently grown for one to three weeks as intraocular grafts to adult male hosts. Grafts of intact rudiments provided additional control data.In heterotypic recombinants composed of urogenital epithelia (urogenital sinus or seminal vesicle) and integumental mesenchyme (back, snout, or plantar), the epithelium responded as if androgens were absent, i.e., urogenital sinus epithelium formed a keratinized structure, while seminal vesicle epithelium developed into a small tubule of columnar epithelium. On the other hand, plastic integumental epithelia (snout or plantar) was transformed by urogenital mesenchyme of the urogenital sinus or seminal vesicle into a glandular epithelium characteristic of the mesenchymal source. Similarly, the normally glandular preputial gland epithelium could be induced to form keratinized, hair‐bearing skin by back and snout skin dermis, and although preputial gland mesenchyme did not manifest inductive properties when associated with integumental mesenchyme, it was able to participate in typical skin differentiation.These data demonstrate (1) the importance of the mesenchyme in mediating epithelial response to androgens, (2) the stability of urogenital epithelia, (3) the plasticity of integumental epithelia, and (4) the inductive properties of urogenital and integumental mesenchyme.
On the presence of mononuclear leucocytes in dorsal root ganglia following transection of the sciatic nerve
Authors: Smith Marshall L. , Adrian Erle K. 
Published: February 2005

AbstractTo label circulating blood mononuclear cells, adult male mice were given multiple injections of tritiated thymidine on the day prior to transection of the right sciatic nerve. These animals and uninjured controls that received a similar sequence of tritiated thymidine injections were sacrificed at intervals up to 64 days following the injury. In the dorsal root ganglia associated with the injured sciatic nerves there were more satellite cells per neuron at all time intervals after the first day than were in the ganglia from the uninjured nerves. The percentage of satellite cells that were labeled was also higher in the ganglia from the injured nerves at all times after injury except the first day. Because no tritiated thymidine should have been available at the time of injury or afterward to label cells proliferating in response to the injury, most of the labeled cells in these ganglia must have been cells labeled before the injury or must be derived from such cells through division. The only large population of labeled cells available to the ganglion was that of the labeled blood mononuclear leucocytes, and the increase in number of labeled cells in the injured ganglia is attributed to infiltration of these cells.
Light and electron microscopic studies on the gastrointestinal tract of the suckling echidna (Tachyglossus aculeatus)
Authors: Krause William J. 
Published: February 2005

AbstractThe stomach of the suckling echidna is lined by a tall columnar epithelium that is bounded basally by a delicate basement membrane. Adjacent cells are held in close apposition by tight junctions near the apex and by extensive implications of the remaining lateral surfaces. The basal cell surface is smooth and without apparent specialization. The lining epithelium is characterized by an abundance of mitochondria and a relative paucity of other organelles. Scattered argentaffin cells extend between the bases of the gastric lining cells and rest upon the luminal side of the basement membrane.Absorptive cells lining the small intestine of the suckling echidna exhibit in‐vaginations of the apical plasma membrane which branch and anastomose, forming a dense network of tubules in the apical cytoplasm. Adjacent to this network is a series of small vacuoles of varying diameters which come into direct relation with a single, large, supranuclear vacuole. The vacuolar system contains both a fine granular substance and clusters of a flocculent amorphous material thought to be of a proteinaceous nature. The surrounding cytoplasm contains numerous profiles of smooth endoplasmic reticulum, several Golgi systems, and a relative abundance of mitochondria. Clusters of homogeneous droplets are found in the cytoplasm and in the intercellular space.
The nuclear envelope in guinea pig spermiogenesis
Authors: Gordon Mildred 
Published: February 2005

AbstractIn early stages of flagellar development the nuclear envelope on either side of the implantation fossa develops numerous pores. With condensation of the nucleus the envelope becomes excessive and these annulated portions of the envelope are reflected off the surface of the nucleus into the cytoplasm of the neck. The evaginated nuclear membranes enclose a residual mass of nucleoplasm which remains after the rest of the nucleus has polymerized, indicating either a storage of previously synthesized substances or a reserve of metabolically active nucleoplasm which may serve for the continued development of flagellar structures. A portion of the evaginated envelope is differentiated from the rest in lacking annuli and having a consistent 150 Å–200ÅA cisternal space. This unannulated section differentiates in association with the adjunct of the proximal centriole and eventually surrounds the terminal end of the adjunct.
Glycogen in the liver during starvation: A histochemical and biochemical investigation
Authors: Otter W. Den , De Minjer A. 
Published: February 2005

AbstractDuring a carbohydrate‐rich diet the liver contains a large amount of evenly distributed glycogen. During a fat‐rich diet glycogen is located mainly in zone 1 of the liver acinus. These results suggest that different acinar enzyme patterns can be induced by different diets. The acinar glycogen patterns remain unchanged during prolonged starvation.The curve of glycogen percentage vs. starvation time has the same general shape as the curve representing the changes in resistance during the general‐adaptation‐syndrome.
Variation in the silver staining of the Golgi complex along the epithelium of the intestinal villi in the adult rat
Authors: Josephson R. L. , Altmann G. G. 
Published: February 2005

AbstractA light microscopic study was carried out on the Golgi complex of the absorptive epithelial cells of the small intestine of adult male rats. Silver impregnation methods (Da Fano's, Aoyama's, and Elftman's) were used. Deposits of silver in the Golgi complex were heaviest in the lower half of the villi. Thereafter, a progressive diminution in the reaction occurred. In the uppermost quarter of the villus no reaction was visible. Villi of the duodenum, midgut, and terminal ileum all exhibited this phenomenon regardless of variations in fixation method, concentration and pH of the silver solutions, exposure time to the silver solutions, and various dietary regimens (high fat, no fat, and starvation). The change observed in the silver reaction of the Golgi complex probably reflects a structural or functional change of this organelle as the absorptive epithelial cells migrate along the villi toward the extrusion zones.
The morphology of enamel rods in thin sections
Authors: Quigley Mervyn B. 
Published: February 2005

AbstractVarious methods of ENcalcification, processing and staining have been investigated to study thin sections of human enamel. EDTA‐Na2 in a phosphate buffer was found to be the ENcalcifier of choice, and a stain utilizing SnF2 and H2S solutions was found to stain the sections a rich dark brown. The sections produced showed a keyhole outline of enamel rods in cross section with no eviENnce of interrod material.
Daily variation in 5‐hydroxytryptamine in rat spleen and the effect of stimuli on the rhythm
Authors: Scheving Lawrence E. , Dunn Jon C. , Pauly John E. , Harrison William H. 
Published: February 2005

AbstractFluorometric measurements were made of 5‐hydroxytryptamine levels in spleens obtained from separate subgroups of adult male rats killed at two‐hourly intervals over four separate 24‐hour time spans. For three weeks prior to obtaining tissue, all rats were standardized carefully and were subjected to 12 hours of light (0600–1800) followed by 12 hours of darkness. Analyses showed in each study very significant fluctuation over the 24‐hour time scale; the range of change over this period was as great as 131%. The phasing of the rhythms, in spite of the rigid environmental synchronization, was not similar in any of the four studies. Possible explanations for this unexpected desynchronization are discussed. Spleen weights also fluctuated with a significant 24‐hour circadian frequency.In addition, the rhythm characterizing this amine was described in female rats as well as the effect of different stimuli on the same rhythm. These stimuli were ether, immobilization and a ‘novelty’ situation; and all three significantly increased the levels of 5‐HT in spleen when the overall 24‐hour mean values of each experimental group were compared with controls. However, in all cases there were discrete time points when significant differences in 5‐HT levels could not be obtained with any of the stimuli. This study demonstrates that the effect of the stimuli used depends on the phase of the rat's circadian system during which it was applied. The necessity of considering the natural rhythmic fluctuation in any investigation evaluating this biogenic amine in spleen is demonstrated.
A reexamination of motility patterns of rat epididymal spermatozoa
Authors: Fray C. S. , Hoffer A. P. , Fawcett D. W. 
Published: February 2005

AbstractThe swimming motion of rat epididymal spermatozoa was reexamined using high speed cinematography. Sperm were filmed at 100 frames per second and viewed at a reduced speed for detailed study. The flagella of spermatozoa from the caput epididymidis exhibit a rigid curved middle piece proximal to the cytoplasmic droplet and a flexible portion distal to the droplet. Bending waves begin at the caudal end of the immobile middle piece and propagate distally. The large majority of sperm from this region of the epididymis swim in a circular fashion, clockwise or counterclockwise, depending on the orientation of the curved midpiece. A few spermatozoa, however, manage to achieve a form of forward progression by alternation of the direction of curvature of their inflexible anterior segment. Spermatozoa from the cauda epididymidis swim progressively forward and rotate frequently about their axis of progression. Propagated waves of bending arise in the neck region and involve the midpiece as well as the more distal segments of the tail. The changing pattern of motility of sperm as they mature in the epididymis is consistent with the hypothesis, suggested by others, that the components of motility may develop independently and sequentially and further suggests that the site of initiation of bending waves is not limited to the centriole.
Penetration of ruthenium red into peripheral nerve fibers
Authors: Singer Marcus , Krishnan N. , Fyae Derek A. 
Published: February 2005

AbstractLiving peripheral nerves immersed in ruthenium red‐Ringer solution in vivo or in vitro and subsequently fixed for electron microscopy reveal dye in the axon and myelin‐Schwann sheath. There is rapid penetration into the agranular reticulum of the axon first at the node of Ranvier and later in the internodal region. Dye is also sequestered in the Schwann cell body, Schmidt‐Lanterman cleft and adaxonal and paranodal Schwann cytoplasm. Moreover, dye is deposited in the major electron dense line of the myelin wrapping.
Cell division in normal and neoplastic mammary gland tissue in the rat
Authors: Grahame R. E. , Bertalanffy F. D. 
Published: February 2005

AbstractMitotic rates of epithelial cells in Sprague‐Dawley rat mammary glands were investigated in the virgin rat, and during pregnancy, lactation and involution. In addition, rates of cell division were determined in mammary gland neoplasms induced by dimethylbenz(a)anthracene (DMBA). The mammary gland epithelium of the virgin rat exhibited a slight but continuous mitotic activity through all phases of the estrous cycle, indicating a low rate of cell renewal. During pregnancy the rate increased markedly, attaining a peak on the twelfth day. The rates of mitosis declined during lactation and involution. The majority of DMBA induced mammary gland neoplasms exhibited mitotic rates lower than the normal mammary gland during pregnancy.
Fertilization of guinea pig eggs in vitro
Authors: Yanagimachi R. 
Published: February 2005

AbstractGuinea pig eggs can be fertilized in vitro in a chemically defined medium originally developed by Biggers, Whitten and Whittingham for the cultivation of fertilized mouse eggs. When unfertilized eggs were inseminated in this medium (abbr. BWW) with fresh epididymal spermatozoa, sperm penetration occurred not earlier than two hours after insemination. Quick and efficient sperm penetration occurred when the eggs were inseminated with spermatozoa pre‐incubated in BWW for 11‐18 hours. Spermatozoa started to pass through the zona pellucida as early as 10‐15 minutes following insemination and all the eggs were penetrated by spermatozoa within one hour. The time needed for functional capacitation of guinea pig spermatozoa is estimated to be no less than two hours under the experimental conditions used, the optimal time possibly being 8‐12 hours or even longer. The possibility of in vitro sperm capacitation and fertilization of eggs in media much simpler than BWW (e.g., Earle's solution with or without albumin) is suggested.
The organization of dense projections in synapses of the brain of a marsupial, Setonix brachyurus
Authors: Jones D. G. , Brearley R. F. , Doran G. A. 
Published: February 2005

AbstractSynaptic junctions from the lateral geniculate nucleus of the quokka brain have been examined by electron microscopy after glutaraldehyde fixation and PTA staining. Junctions can be divided into two groups: discontinuous‐continuous and continuous‐continuous, depending on the continuity or lack of it of the presynaptic membrane. The postsynaptic membrane always has a continuous appearance.The dense projections have the following characteristics: 1. an irregular outline due to the presence of spikes; 2. in some cases, an external electron‐opaque “skin” and an internal, relatively electron‐translucent core; 3. adjacent projections may have one or more stands of the presynaptic network between them and extending to the internal coat of the presynaptic membrane; 4. the gap between the bases of dense projections varies from 5 to 69 nm, with a mean value of 23 nm. Seventy‐six percent of these measurements fall within the range 5‐25 nm, while many of the larger gaps separating dense projections are subdivided into smaller components by the presence of one or more strands of the presynap‐tic network.Features 2 and 3 have not been previously described in exactly the form seen here. It is not known whether they are confined to marsupial synapses or whether they highlight important general features of synaptic organization.
Electron microscopic studies on von Korff fibers in the human developing tooth
Authors: Whittaker D. K. , Adams D. 
Published: February 2005

AbstractDeciduous tooth germs were removed from the anterior region of human fetuses between 13‐16 weeks of age and fixed in glutaraldehyde. Some were post fixed in osmium tetroxide whilst others were block stained with silver nitrate and prepared for electron microscopy. Thick Araldite embedded sections were cut at 1 μm and stained in various ways for examination by light microscopy. Thin sections of bulk silver stained material were examined with the electron microscope before and after staining with heavy metals.Fibers lying between the developing odontoblasts were demonstrable under the light microscope and their appearance was consistent with the classical description of von Korff fibers. With the electron microscope bundles of collagen fibers up to 1 μm in diameter were present between newly differentiated odontoblasts. Heavy metal staining of sections from bulk silver impregnated material revealed that silver deposition was associated mainly with collagen fibrils. It is concluded that in the crown of human developing teeth, bundles of collagen fibrils are present between the newly differentiated odontoblasts and that these bundles represent those usually described as von Korff fibers.Similar results were found using material from developing molar teeth of mice.
Effect of testosterone, dexamethasone and hypophysectomy on membranous whorls in the adrenal gland of the Mongolian gerbil
Authors: Nickerson Peter A. 
Published: February 2005

AbstractThe effect of stress‐induced release of ACTH or suppression of ACTH release on concentric whorls of rough endoplasmic reticulum has been studied in the adrenal gland of the Mongolian gerbil. The border zone between the zona fasciculata and reticularis appears to be a zone of transition, and stress may transform these cells into typical zona fasciculata cells. Absence (hypophysectomy) or reduction (testosterone, dexamethasone) of ACTH however causes neither atrophy nor hypertrophy of whorls. The stress of saline injections for five days caused disappearance of whorls and a rise in blood cortisol to 1.5 times that in controls. Whorls were replaced by a focal accumulation of smooth endoplasmic reticulum. Testosterone or dexamethasone as well as transaural hypophysectomy prevented the disappearance of whorls in spite of the stress of injection. Testosterone caused a 50% reduction in blood cortisol levels whereas both dexamethasone and hypophysectomy reduced blood cortisol to 25% of that in controls.
Structural changes in the proximal tubule of kidneys from hypophysectomized rats
Authors: Evan Andrew P. , Simone P. George , Solomon Sidney , Loker Edward F. 
Published: February 2005

AbstractThe present study was undertaken to determine what structural changes hypophysectomy would cause in the rat kidney. Proximal convoluted tubule cells from hypophysectomized rats were smaller and their length was decreased when compared to kidneys from control animals of approximately the same weight as the hypophysectomized animals. Electron microscopic observation of the kidneys from the hypophysectomized rats revealed that the cells of the proximal convoluted tubules had (1) an increase in size and number of dense bodies (type II cytosome); (2) a decrease in smooth endoplasmic reticulum (SER); (3) a decrease in basilar infoldings; (4) an increase in the frequency of mitochondria cristae aligned in their longitudinal axis and (5) a change in the character of the profiles of smooth endoplasmic reticulum (SER) related to microbodies (type I cytosome) from a vesicular to tubular arrangement. The changes noted in the cells of the proximal convoluted tubules of hypophysectomized rats were similar to previously described changes observed in tubular atrophy.
Twenty‐four‐hour rhythmicity in carbonic anhydrase activities of choroid plexuses and pineal gland
Authors: Quay W. B. 
Published: February 2005

AbstractCarbonic anhydrase (CA, carbonate hydro‐lyase, EC 4.2.1.1) activity of choroid plexuses (ventricles I + II and IV) and pineal glands of adult male rats was determined by microtitration. Autopsies at precise times in relation to a daily photoperiod 14 hours long allowed in replicate series evaluation of 24‐hour rhythmicity. A slightly lower choroid CA activity during the light phase was variable and marginal in significance. A highly significant and reproducible daily fall in pineal CA activity near the onset of light was paralleled by, and probably originated from, a fall in pineal content of erythrocytes. Low pineal CA activity is consistent with its endocrine nature. Its morning changes in hemodynamics are likely to be due to local changes in content and release of norepinephrine and other vasoactive agents.
The nuclear envelope: Its breakdown and fate in mammalian oogonia and oocytes
Authors: Szollosi Daniel , Calarco Patricia G. , Donahue Roger P. 
Published: February 2005

AbstractThe dissolution of the nuclear envelope (NE) has been studied ultrastructurally in mouse oocytes maturing in vitro. NE breakdown begins with the undulation of the nuclear envelope followed by the disappearance of nuclear pores. Subsequently, extensive NE convolutions, possibly caused by impinging microtubules, result in the apposition of adjacent NE segments, the appearance of breaks and the formation of NE doublets. Doublets may also be formed by the apposition of intranuclear cisternae to the inner leaflet of the NE. Nuclear envelope breakdown in mouse oocytes takes approximately three and one‐half hours in vitro.The fate of the resulting nuclear envelope fragments has been followed in both mouse oocytes and human oogonia. In the mouse, NE doublets separate into individual cisternae, indistinguishable from endoplasmic reticulum, by the time of the first meiotic metaphase. A different fate for NE doublets is suggested in human oogonia which retain NE doublets throughout the division cycle. The nuclear envelope of the daughter cells reforms, at least in part, from NE doublets by separation of the apposed cisternae into single units and the re‐establishment of chromosomal contact. Thus, at least some of the NE appears to be conserved in actively dividing human oogonia.
A morphological and histochemical evaluation of sexual dimorphism in androgen‐insensitive pseudohermaphroditic mice
Authors: Andrews Edwin J. , Bullock Leslie P. 
Published: February 2005

AbstractExamination of the morphology in the submandibular salivary gland, adrenal gland and renal cortex of androgen‐insensitive, tfm/ Y mutant mice has revealed predominantly female characteristics. A sexual dimorphism in alkaline‐phosphatase (AP) activity was seen in the submandibular salivary gland of this strain of mice; the AP activity in the mutants was similar to females. There was no dimorphism in renal AP activity.
Correlation of vascularity with mineralization in human fetal teeth
Authors: Tobin Charles E. 
Published: February 2005

AbstractThe qualitative relationship of dental vascularity to mineralization of dentin and enamel was studied in 50 normal human fetuses 11.5 to 18 weeks of age, obtained unembalmed within 12‐24 hours after abortion. A 50‐50 suspension of India ink and 10% neutral formalin was injected manually into the umbilical vein (intact fetuses) or internal carotid arteries (autopsied fetuses), using sufficient pressure on the syringe to fill but not rupture nor overdistend the blood vessels. After immersion of the injected fetuses in 10% neutral formalin for three to five days, the maxillae and mandibles were removed and stained with alizarin red S for identification of calcium salts. Under magnification the dental sacs were exposed, removed intact and opened to observe: (1) the dental papilla, (2) its size and vascularity, and (3) the extent of mineralization of the crowns and cusps. Macroscopic preparations and microscopic sections were made of selected tissues from these specimens. The degree of mineralization appeared to be correlated more closely with the vascularity of the dental papilla than with the total size of the dental sacs, or that of the cusps or crowns. Blood vessels were present at the peripheral edge of both the developing enamel and dentin but no blood vessels were found to traverse the stellate reticulum nor were any blood cells found within it normally; whereas if abnormal pressure had been applied to the fetus or if the specimens were undergoing maceration, blood cells were observed within the stellate reticulum.